ORCID Profile
0000-0001-8676-7461
Current Organisations
Royal Melbourne Institute of Technology
,
University of Wollongong
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Publisher: Wiley
Date: 04-04-2012
DOI: 10.1111/J.1742-6723.2012.01550.X
Abstract: Access block (AB) and hospital overcrowding adversely affect ED functionality. ED throughput measures have been described in the literature with positive impacts on key performance indicators (KPIs)--time to first seen, did-not-wait rates, off-stretcher times for ambulances and ED length of stay figures. In this study, we aimed to assess the impact of a new model of care, the Senior Streaming Assessment Further Evaluation after Triage (SAFE-T) zone concept on ED performance indicators and statistical outcomes. We implemented a model of care at our tertiary hospital ED amalgamating multiple ED throughput interventions. These interventions included dynamic transition waiting room concept, early senior ED physician assessment and decision-making, early streaming, acute-care bed quarantining and ED short stay and observation units. The principal intervention was the SAFE-T zone. End-point data were compared for similar periods (77 days) of 2010 and 2011 with and without the new model of care. In total, 11 408 and 11 845 patients were included in the study periods pre- and post-intervention, respectively. Time to physician KPI improved from 72.5% to 84.1%. Did-not-wait rates dropped from 10.7% to 9.6% (P= 0.02) and off-stretcher times for ambulances KPI improved from 74.5% to 79.5% (P < 0.001). ED length of stay dropped most significantly for Australasian Triage Scale categories 3 and 4 (14.3% and 11.8%, P-values <0.001). These results were achieved despite worsened AB and hospital bed-occupancy rates during the intervention period (+3.9% and +6.7%). The SAFE-T zone model of care involving multiple ED throughput measures achieved improvements in ED performance despite AB and hospital overcrowding.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2019
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.794.232
Abstract: High-strength steel is a type of alloy steel that provides better mechanical properties or greater resistance to corrosion than carbon steel. Strip shape is an important factor affecting the strip quality significantly for the rolled products. Because of the complex influence factors of plate shape and profile, shape detection and control technology have not been solved, especially for high strength steel rolling. In this paper, a novel three dimensional finite element simulation of the strip shape and flatness of high strength steel has been proposed. The material constitutive model has been built up based on experimental results through the Gleeble 3800 Thermal Simulator under different temperatures and stain rates. The modelling of roll elastic deformation system, roll gap profile and edge drop has been set up systematically considering the influence of the work roll transverse shifting and roll bending. Results have shown that both higher bending force and more roll shifting will significantly reduce the strip crown, and obtain improved edge drop distribution as well. The proposed numerical model has been validated through hot rolling experiments in 4-high rolling mills.
Publisher: Wiley
Date: 16-04-2017
Abstract: The ED discharge stream short stay units (EDSSUs) aim to facilitate patient flows through EDs. We investigate the relationship between EDSSU census and hospital bed occupancy rates (BORs) on National Emergency Access Target (NEAT) performance and did-not-wait (DNW) rates at a tertiary metropolitan adult ED in Sydney, Australia. We collated data for all ED presentations between 1 January 2012 and 31 December 2014. Daily ED, EDSSU census and ED-accessible hospital BORs were tabulated with daily ED NEAT performance and DNW rates. Non-parametric regression analyses was conducted on cohorts of appropriate, inappropriate, successful and failed EDSSU admissions based on local admission policies and BOR for NEAT and DNW outcomes. Among all presentations (n = 192 506) during the study period, 43.8% of patients were admitted in hospital including 10.4% for EDSSU (n = 20 081). Analyses reveal modest positive correlation of EDSSU admissions with NEAT performance (τ = 0.35, P < 0.001) and weak negative correlation with DNW rates (τ = -0.29, P 100% (τ = 0.39 and τ = -0.36, P 100% were associated with reduced EDSSU admits, NEAT performance and increased DNW rates (P < 0.001). Appropriate EDSSU admissions had shorter EDSSU length of stay than inappropriate EDSSU admissions (350 vs 557 min, median difference -158 min, P < 0.001). Appropriate use of EDSSU provides effective conduit for ongoing patients' management beyond mandated timelines. Health systems should focus on reducing hospital BORs to mitigate exclusive ED pressure to deliver NEAT performance targets.
Publisher: Trans Tech Publications, Ltd.
Date: 07-05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.922.183
Abstract: A high carbon steel (HCS) and low carbon steel (LCS) bimetal was fabricated by centrifugal composite casting. Two different thermomechanical treatments (TMT1 and TMT2) were employed to improve the mechanical properties of the bimetal. TMT1 process includes 60% of overall reduction by hot compression with temperatures of 1100 and 800 o C, respectively. While TMT2 process involves 60% of overall reduction using the two-step deformation method, which is a combination of non-isothermal compression cooling from 1100 to 800 o C and isothermal compression at 800 o C. The flow stress behavior, microstructural evolution and microhardness variation were analysed. Experimental results show that both TMT processes contributed to the improvement in mechanical properties resulting from a refinement of the grain size and an increase of density of pearlitic lamella in HCS layer. However, TMT2 process gave a better efficiency and a more significance in improvement of properties with the evidence of the same overall reduction leading to a higher microhardness.
Publisher: MDPI AG
Date: 17-02-2021
DOI: 10.3390/MA14040944
Abstract: The effects of the wet milling rotating speed on the number of graphene layers and graphene quality, and the conversion efficiency of graphite exfoliate to graphene, were investigated by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results show that the number of few-layer graphene nanometer sheets (GNSs) (≤10 layers) gradually increases with the increase of rotational speed in the range of 160–240 rpm. The proportion of GNSs with 0–10 layers reaches more than 80% as the rotational speed is increased to 280 rpm. GNS defect types in the composite materials are marginal defects with minimal influence and almost no oxidation. In the range of 160–280 rpm, the intensity of graphite peak decreases and the conversion efficiency of graphene increases with the increase of rotational speed. This is the same as the experimental result obtained by HRTEM.
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/424131
Abstract: In flexible microrolling, springback in thickness direction is a critical indicator to determine the forming quality. Accurate prediction of springback is one of the significant aspects in the finite element analysis of flexible microrolling. Meshing is a step of great importance in finite element analysis of manufacturing process as it directly determines the accuracy of the FEA results as well as the requested computational time. This paper presents a numerical study on revealing the mesh effects on the accuracy of springback estimation utilising ABAQUS/Standard for modelling and analyses. Two types of meshes with six mesh sizes for each mesh type are considered in this study and the optimal mesh type and mesh size have been found to obtain accurate value of springback while saving as much computational time as possible.
Publisher: Wiley
Date: 26-11-2017
Abstract: The Sepsis-3 task force recommends the use of the quick Sequential Organ Failure Assessment (qSOFA) score to identify risk for adverse outcomes in patients presenting with suspected infection. Lactate has been shown to predict adverse outcomes in patients with suspected infection. The aim of the study is to investigate the utility of a post hoc lactate threshold (≥2 mmol/L) added qSOFA score (LqSOFA Retrospective cohort study was conducted on a merged dataset of suspected or proven sepsis patients presenting to ED across multiple sites in Australia and The Netherlands. Patients are identified as candidates for quality improvement initiatives or research studies at respective sites based on local screening procedures. Data-sharing was performed across sites of demographics, qSOFA, SOFA, lactate thresholds and outcome data for included patients. LqSOFA In a merged dataset of 12 555 patients where a full qSOFA score and outcome data were available, LqSOFA The lactate ≥2 mmol/L threshold-based LqSOFA
Publisher: IOP Publishing
Date: 27-04-2020
Abstract: Novel water-based nanolubricants using TiO 2 nanoparticles (NPs) were synthesised by adding sodium dodecyl benzene sulfonate (SDBS) and glycerol, which exhibited excellent dispersion stability and wettability. The tribological performance of the synthesised nanolubricants was investigated using an Rtec ball-on-disk tribometer, and their application in hot steel rolling was evaluated on a 2-high Hille 100 experimental rolling mill, in comparison to those without SDBS. The water-based nanolubricant containing 4 wt% TiO 2 and 0.4 wt% SDBS demonstrated superior tribological performance by decreasing coefficient of friction and ball wear up to 70.5% and 84.3%, respectively, compared to those of pure water. In addition to the lubrication effect, the suspensions also had significant effect on polishing of the work roll surface. The resultant surface improvement thus enabled the decrease in rolling force up to 8.3% under a workpiece reduction of 30% at a rolling temperature of 850 °C. The lubrication mechanisms were primarily ascribed to the formation of lubricating film and ball-bearing effect of the TiO 2 NPs.
Publisher: Elsevier BV
Date: 02-2021
Publisher: IOP Publishing
Date: 13-05-2019
Publisher: MDPI AG
Date: 20-08-2021
DOI: 10.3390/MET11081317
Abstract: In this paper, electrochemical corrosion tests and full immersion corrosion experiments were conducted in seawater at room temperature to investigate the electrochemical corrosion behavior and the corrosion mechanism of high-strength EH47. The polarization curve, EIS (electrochemical impedance spectroscopy), SEM (scanning electron microscope), and EDS analyses were employed to analyze the results of the electrochemical corrosion process. The electrochemical corrosion experiments showed that the open circuit potential of EH47 decreases and then increases with an increase in total immersion time, with the minimum value obtained at 28 days. With an increase in immersion time, the corrosion current density (Icorr) of EH47 steel first decreases and then increases, with the minimum at about 28 days. This 28-day s le also showed the maximum capacitance arc radius, the maximum impedance and the minimum corrosion rate. In the seawater immersion test in the laboratory, the corrosion mechanism of EH47 steel in the initial stage of corrosion is mainly pitting corrosion, accompanied by a small amount of crevice corrosion with increased corrosion time. The corrosion products of EH47 steel after immersion in seawater for 30 days are mainly composed of FeOOH, Fe3O4 and Fe2O3.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Publisher: Chinese Journal of Mechanical Engineering
Date: 2006
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 11-2013
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1017.435
Abstract: The composition and phase transformation of oxide scale in cooling process (after hot rolling) of rolled microalloyed steels affect tribological features of rolled strip and downstream process, and the produced steel surface quality. In this study, physical simulation of surface roughness transfer during cooling process with consideration of ultra fast cooling (UFC) was carried out in Hille 100 experimental rolling mill, the obtained oxide scale was examined with SEM to show its surface and phase features. The results indicate that the surface roughness of the oxide scale increases as the final cooling (coiling) temperature increases, and the flow rate of the introduced air decreases. The cracking of the surface oxide scale can be improved when the cooling rate is 20 °C/s, the strip reduction is less than 12 %, and the thickness of oxide scale is less than 15 μm, independent of the surface roughness. A cooling rate of more than 70 °C/s can increase the formation of retained wustite and primary magnetite precipitates other than the precipitation of α-iron. This study is helpful in optimising the cooling process after hot rolling of microalloyed steels to obtain quality surface products.
Publisher: Trans Tech Publications Ltd.
Date: 09-02-2008
Publisher: Trans Tech Publications Ltd.
Date: 09-02-2008
Publisher: Informa UK Limited
Date: 24-06-2019
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 2013
Publisher: Japan Institute of Metals
Date: 02-2020
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.1606
Abstract: The friction is a key factor that influences the surface quality in metal forming. To figure out the relationship between the friction and the surface roughening, a finite element model is employed in the commercial finite element software ABAQUS to simulate the surface roughness of top side of Al plate during uniaxial planar compression. With the change of friction conditions, the surface roughening varies. The average surface roughness (Ra) shows a relationship with the friction coefficient. During the surface roughening process, the grain slip takes place in the “soft orientation”, and the “hard orientations” become the barrier of the slip.
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.622-623.330
Abstract: The high carbon steel (HCS)/low carbon steel (LCS) laminated composite made by centrifugal casting technology was subjected to hot compression tests on Gleeble 3500 thermomechanical simulator in a range of temperatures (800-1100 o C) and strain rates (0.02-10 s -1 ). The hot-working behavior of the laminate was characterised by analysing the flow stress-strain curves and constructing the processing map based on dynamic materials model via superimposing efficiency of power dissipation and flow instability maps. The safe and unsafe processing conditions were identified in the processing map which was validated by microstructural examinations. Banded microstructure and micro-shear cracks occurred in the unsafe domains were responsible for the flow instability, while dynamic recrystallisation in stable domains with high efficiency of power dissipation imparted a good workability to the laminate. The optimum hot-working parameters were determined to be: (i) 800-1050 o C and 0.02-0.04 s -1 , (ii) 800-1045 o C and 2.5-10 s -1 and (iii) 1050-1100 o C and 0.02-2.5 s -1 .
Publisher: Elsevier BV
Date: 10-2006
Publisher: Trans Tech Publications, Ltd.
Date: 02-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.476-478.508
Abstract: Grain size, shape and orientation play an important role on the deformability of micro workpiece as the geometrical dimensions approach to a characteristic scale in micro-forming process. This paper addresses the three-dimensional (3D) finite element (FE) model with weighed centroidal voronoi diagram (WCVD). Steady-state grains are generated when the voronoi generating points approach the grain centroid utilising a simplex integration algorithm. As a result of the centroidal process, the topological features of grains advance the uniform and steady state gradually, which may cause a decrease of interfacial energy. The grain size distribution is compared between the 3D domain and random cross-sectional plan. The effects of centroidal process on the distributions of grain size and number of grain corners, facet and edge are analysed.
Publisher: Springer Science and Business Media LLC
Date: 03-01-2021
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.1602
Abstract: In twin-roll thin strip casting, the temperature of casting roll affects the roll thermal stress, and influences the thermal deformation, the generation of roll surface cracks, the strip shape and the service life of casting roll. In this paper, the features of the casting roll materials have been analysed, the effects of the clad materials and thickness on temperature field of the casting roll have been simulated and discussed. The developed temperature model of casting roll is helpful in optimising processing parameters and the design of casting roll during twin-roll thin strip casting.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.894.212
Abstract: Strip profile control during rolling is required to assure the dimensional quality of rolled thin strip is acceptable for customers. Throughout rolling, the strip profile is controlled by using the advanced shape control rolling mill, such as the combination of work roll crossing and shifting during asymmetrical rolling, the one of the valuable methods to control the strip profile quality in rolling process. In this paper, the influences of cold rolling parameters such as the crossing angle and axial shifting value of work rolls on the strip profile are analysed. The strip shape control is discussed under both symmetrical and asymmetrical rolling conditions. The obtained results are appropriate to control the rolled thin strip profile in practice.
Publisher: Hindawi Limited
Date: 15-11-2018
DOI: 10.1155/2018/5287945
Abstract: This paper presents a constitutive modelling of the polycrystalline thin metal strip under a state of combined loading in microflexible rolling. The concept of grained inhomogeneity is incorporated into the classic Chaboche hardening model that accounts for the Bauschinger effect, in order to provide more precise description and analysis of the springback mechanism in the particular forming operation. The model is first implemented in the finite element program ABAQUS to numerically predict the stress-strain relationship of 304 stainless steel specimens over a range of average grain sizes. After validation of the developed model by comparison of predicted curves and actual stress-strain data points, it is further applied to predict the thickness directional springback in microflexible rolling of 304 stainless steel strips with initial thickness of 250 µ m and reduction changing from 5 to 10%. The model predictions show a reasonable agreement with the experimental measurements and have proven to be more accurate than those obtained from the conventional multilinear isotropic hardening model in combination with the Voronoi tessellation technique. In addition, the variation of thickness directional springback along with the scatter effect is compared and analysed in regard to the average grain size utilising both qualitative and quantitative approaches in respect of distinct types of data at different reductions.
Publisher: Elsevier BV
Date: 2014
Publisher: ASME International
Date: 25-04-2005
DOI: 10.1115/1.1794159
Abstract: Friction at the interfaces between two rolls and a strip being plastically deformed by the rolls is an important consideration in both theory and practice of metal forming. In this paper, a 3D rigid viscoplastic finite element method (FEM) was used to model the rolling deformation of ribbed strip, taking into account friction variation in the roll bite. The calculated results such as the rolling forces, torque, and the rib height of the rolled product while considering friction variation in the roll bite are compared with the measured results obtained from the experiments. The simulation shows that when the friction variation is taken into account, the results are in good agreement with the experimental ones.
Publisher: Trans Tech Publications Ltd.
Date: 09-02-2008
Publisher: Trans Tech Publications, Ltd.
Date: 02-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.194-196.144
Abstract: The as-rolled and enamel fired microstructure and mechanical properties of two low carbon steels with different compositions were analysed in the paper. The results show that the grains do not coarsen in lab firing process, and could be refined after industrial enamel firing process. The strength can keep stable in the firing process and the impact energy could be enhanced greatly under the industrial enamel firing process. The surface decarburized layer was occurred as a result of chemical reaction among the carbon in steel and water, oxides in the enamel frit.
Publisher: Computers, Materials and Continua (Tech Science Press)
Date: 26-10-2018
Publisher: Trans Tech Publications, Ltd.
Date: 03-2007
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 12-2002
Publisher: Japan Society of Mechanical Engineers
Date: 2003
DOI: 10.1299/JSMEA.46.218
Publisher: ASME International
Date: 16-10-2018
DOI: 10.1115/1.4041365
Abstract: In this paper, a calculation method based on matlab partial differential equations (PDE) tool is proposed to investigate the static characteristics of aerostatic spherical bearings. The Reynolds equation of aerostatic spherical bearings is transformed into a standard elliptic equation. The effects of geometric parameters and operational conditions on the film pressure, bearing film force, and stiffness are studied. The axial and radial eccentricities result in different film pressure distributions the bearing film force and stiffness are significantly influenced by geometric parameters and operational conditions. The relative optimal parameters are confirmed based on the calculation results. A comparison between the numerical and experimental results is also presented. The highest relative error between the numerical results and the experimental data is 11.3% the calculation results show good agreements with the experimental data, thus verifying the accuracy of the calculation method used in this paper.
Publisher: Elsevier BV
Date: 08-2014
Publisher: Springer Science and Business Media LLC
Date: 26-06-2019
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 09-2020
Publisher: Trans Tech Publications, Ltd.
Date: 08-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.126-128.987
Abstract: In this paper, the effects of the surface asperity wavelength, reduction and lubrication (friction) on the surface roughness transformation of the oxide scale have been studied. The simulation results show that the oxide scale surface roughness decreases with an increase of the average asperity wavelength and reduction. The initial surface roughness affects the decrease rate of surface roughness when the reduction increases. The surface roughness of the oxide scale and steel is quite close when the rolling with lubrication and both of them are reduced with reduction, and the surface roughness of the oxide scale is reduced less comparing with that of without lubrication case. The calculated roughness is close to the measured data.
Publisher: Trans Tech Publications, Ltd.
Date: 03-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.97-101.2955
Abstract: Asymmetrical rolling is usually used on some special rolling produce. It offers lower rolling pressure, more reduction and better crystallographic textures. In recent years asymmetrical rolling has become more important due to realization of improved properties of the strip. In this paper, a elasto-plastic finite element method code has been developed to simulate the asymmetrical rolling of strip, considering unequal roll radii, unequal speed ratio between the upper roll and lower roll, different exit thickness and different reduction. Meanwhile, The profile, crown and edge drop of strip, as well distribution of front tensile stress were discussed in different rolling process. It makes better preset values for the online control system and good results was obtained.
Publisher: Wiley
Date: 02-11-2017
Abstract: Sepsis has recently been redefined as acute organ dysfunction due to infection. The ED plays a critical role in identifying patients with sepsis. This is challenging due to the heterogeneity of the syndrome, and the lack of an objective standard diagnostic test. While overall mortality rates from sepsis appear to be falling, there is an increasing burden of morbidity among survivors. This largely reflects the growing proportion of older patients with comorbid illnesses among those treated for sepsis.
Publisher: Inderscience Publishers
Date: 2008
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 08-2013
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 05-2018
Publisher: Springer Science and Business Media LLC
Date: 09-04-2016
Publisher: Trans Tech Publications, Ltd.
Date: 11-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.409.736
Abstract: The bubble structures, fishscaling resistance, adhesion and its mechanism of vitreous enamel to low carbon steels were evaluated by microscopic methods. The results show that the microalloying elements deteriorates the adhesion but suppress the fishscaling tendency, the enamel-steel interface adhesion could be explained as mainly the mechanical interlocking and chemical bonding during the firing process the lower carbon substrate causes higher proportion of bigger bubbles in the enamel layer and subsequently causes the lower fishscaling susceptibility.
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.652-654.988
Abstract: Uniformity of microstructure and mechanical properties is required for the heavy section steel. In the present work, a heavy section wind tower flange was manufactured by controlled ring-rolling. Post-rolling heat treatment was employed to optimize the microstructure and mechanical properties. The chemical composition, microstructure and mechanical properties in different zones of the flange were investigated. The results showed that the chemical composition and microstructure were uniformly distributed in the flange. The tensile strength showed similar values in different s ling locations. The strain and impact energies of specimens prepared along the longitudinal direction were higher than that prepared along both the radius and thickness directions. Notch direction did not have noticeable effect on the impact energy. It is demonstrated that the designed process is effective for producing heavy section steel with improved quality.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.189-193.2980
Abstract: In this paper, finite element models of the strip shape during cold rolling of thin strip in both symmetrical and asymmetrical rolling cases have been successfully developed, and the effects of rolling parameters on strip shape such as the thickness distribution along the strip width have been obtained. The strip edge drop and shape are discussed under both symmetrical and asymmetrical rolling conditions. Simulation results show that the asymmetrical rolling can reduce the strip edge drop dramatically, which is useful in improving the strip shape and reducing the energy cost during cold rolling of thin strip. The developed finite element model has been verified with the experimental value. The obtained results are applicable to control the rolled thin strip shape in practice.
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 02-2001
Publisher: Wiley
Date: 12-04-2016
Abstract: Systemic inflammatory response syndrome (SIRS)-based severe sepsis screening algorithms have been utilised in stratification and initiation of early broad spectrum antibiotics for patients presenting to EDs with suspected sepsis. We aimed to investigate the performance of some of these algorithms on a cohort of suspected sepsis patients. We conducted a retrospective analysis on an ED-based prospective sepsis registry at a tertiary Sydney hospital, Australia. Definitions for sepsis were based on the 2012 Surviving Sepsis C aign guidelines. Numerical values for SIRS criteria and ED investigation results were recorded at the trigger of sepsis pathway on the registry. Performance of specific SIRS-based screening algorithms at sites from USA, Canada, UK, Australia and Ireland health institutions were investigated. Severe sepsis screening algorithms' performance was measured on 747 patients presenting with suspected sepsis (401 with severe sepsis, prevalence 53.7%). Sensitivity and specificity of algorithms to flag severe sepsis ranged from 20.2% (95% CI 16.4-24.5%) to 82.3% (95% CI 78.2-85.9%) and 57.8% (95% CI 52.4-63.1%) to 94.8% (95% CI 91.9-96.9%), respectively. Variations in SIRS values between uncomplicated and severe sepsis cohorts were only minor, except a higher mean lactate (>1.6 mmol/L, P 2 mmol/L rather than >4 mmol/L performed better. ED sepsis registry-based characterisation of patients may help further refine sepsis definitions of the future.
Publisher: Trans Tech Publications, Ltd.
Date: 09-2019
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.971.3
Abstract: Pure titanium TA1 foil with a thickness of 0.05mm under different grain sizes were carried out by the DT-C539 micro-st ing machine in the laboratory. The size effect of the pure titanium TA1 foil with grain sizes of 3, 7, 9 and 23 microns respectively on surface morphology of the microst ing s le were studied. It is found that the st ing s les with good surface quality can be obtained on the condition that the grain size is 23 microns and the st ing speed is 1mm/s. VORONOI model was established by using ABAQUS, NEPER and MATLAB software. Heterogeneous finite element simulation was carried out for the micro-st ing process under the same conditions. The results showed that the simulation results were more consistent with the experimental results.
Publisher: Elsevier BV
Date: 03-2017
Publisher: Springer Science and Business Media LLC
Date: 17-03-2016
Publisher: Springer Science and Business Media LLC
Date: 03-2018
Publisher: Informa UK Limited
Date: 07-07-2020
Publisher: Wiley
Date: 21-12-2018
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 09-2014
Publisher: MDPI AG
Date: 22-03-2020
DOI: 10.3390/MET10030405
Abstract: A comprehensive research on the flat rolling deformation characterization of microwire has been conducted systematically through finite element simulation and testified by the results from the experimental analysis. The obtained results are compared in terms of lateral spread, geometrical characteristic, contact area width and surface roughness considering the effects of pass reduction and initial wire diameter. The size effect has been identified and surface layer modeling has been set up based on surface grain share and grain size distribution. The numerical method combined with varied flow stress has been verified by experimental value with a maximum difference of 3.7% for the 1.5 mm wire. With the increase of the height reduction, the curvature radius is decreased while the lateral spread and contact area width are increased. Surface roughness evolution in the range of 0.52–0.85 µm for the rolled wire has also been investigated.
Publisher: Springer Science and Business Media LLC
Date: 29-03-2022
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 2017
Publisher: American Scientific Publishers
Date: 08-2012
Publisher: Trans Tech Publications, Ltd.
Date: 10-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.572.249
Abstract: Precipitation behavior of magnetite particles in the thermal grown oxide scale during isothermal cooling of microalloyed low carbon steel was studied using scanning electron microscopy (SEM) and thin film X-ray. The oxide scale was generated from Gleeble 3500 Thermal Mechanical Simulator connected with a humid air generator, to simulate 550 and 450C isothermal treatments. Several types of magnetite precipitates were observed during different cooling processes with respect to the possible mechanisms of precipitation have been discussed. It is found that magnetite particles is as a result of pro-eutectoid precipitation from oxygen-rich wustite, and also as a product of the partial decomposition of wustite during the cooling process due to change of oxygen concentration and migration of iron ions. Furthermore, microalloyed elements in steel reduce the stability of wustite thereby facilitate the precipitation process, whose products of multi-phase oxide finally determine the adhesive strength of oxide scale and steel substrate.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2022
Publisher: Elsevier BV
Date: 12-2008
Publisher: BMJ
Date: 2018
Publisher: Elsevier BV
Date: 02-2014
Publisher: Elsevier BV
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 17-05-2018
Publisher: Elsevier BV
Date: 09-2009
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 11-2006
Publisher: Springer Science and Business Media LLC
Date: 26-02-2012
Publisher: Springer Science and Business Media LLC
Date: 11-02-2015
Publisher: Elsevier BV
Date: 02-2019
Publisher: Springer Science and Business Media LLC
Date: 05-01-2014
Publisher: SAGE Publications
Date: 27-10-2011
Abstract: The aim of this study is to develop a seawater hydraulic piston pump for the power pack of an underwater tool system. A pump with check valves and oil–water-separated structure was selected for the purpose of improving its tolerance to particles when applied in open-circuit system. A novel ‘anti-loosening’ structure was introduced for the piston/shoe assembly. To improve the anti-wear and anti-corrosion performances of the piston and sleeve pairs under seawater lubrication, carbon fibre-reinforced polyetheretherketone was injected as an inner of the sleeve, and synthesized WC was formed on the piston with improved surface hardness. The unbalance problem of the shaft assembly was solved based on Solidworks software by adjusting the centre of mass of the shaft to its rotation axis and making all the products of inertia close to zero for an arbitrary-given coordinate system in which one of its axes is at the rotation axis. Basic performances and reliability experiments for the pump were carried out on a test rig. The shaft assembly was verified by experiment to reach very desirable balance effect. The pump has relative high efficiency at 10 MPa rated pressure and 14 MPa maximum pressure. After 300 h durability test, neither excessive wear could be found for the piston/sleeve pairs as well as other parts in the pump, nor obvious performance degradation happened to the pump. The dynamic balancing method presented in this article provides an easy and effective way to solve the unbalance problem for a shaft with special structure and can be widely used in other rotating machines. New design on the seawater hydraulic pump was initially confirmed to be feasible, although further research needs to be conducted. The pump has been successfully applied in an underwater seawater hydraulic tool system.
Publisher: American Scientific Publishers
Date: 07-2012
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.222
Abstract: Cracks in metal product significantly decrease quality and productivity of the rolled thin strip. In this paper the stress intensity factor (SIF) solution of edge crack defect of thin strip during cold rolling was investigated, and a globe analysis was applied to the problem of free edge of thin strip. The effective stress intensity factor range is important because it represents the major physical cause of crack growth. The present study provides insights of the mechanics of edge crack growth that has been frequently observed during thin strip rolling. The efficiency and reliability of the SIF analytical modelling has been demonstrated. The proposed method for predicting edge crack is useful for producing defect-free products in rolling, and provides insights of the mechanism of edge crack growth.
Publisher: Elsevier BV
Date: 06-2009
Publisher: Elsevier BV
Date: 03-2013
Publisher: Elsevier BV
Date: 02-2008
Publisher: Walter de Gruyter GmbH
Date: 26-01-2018
Abstract: The effect of a dissipative ladle shroud (DLS) on mixing in tundish was investigated, compared with that of a conventional ladle shroud (CLS) using mathematical and physical modelling. The tracer profiles of mathematical results, achieved using large eddy simulation, were validated by physical observations employing high-speed cinephotography. The design of a DLS dramatically changed the flow patterns and contributed the intermixing of fluid elements inside the ladle shroud. The vortex flow encouraged the turbulent mixing and was verified by tracking of physical tracer dispersion inside the DLS. Residence Time Distribution (RTD) curves were obtained in two different sized tundishes to examine the mixing behaviours. The findings indicated that the DLS benefited the tundish mixing in terms of increasing active volume. The effect seemed to be more remarkable in the smaller tundish. The DLS gave rise to a more plug-like flow pattern inside the tundish, showing potential to shorten the transition length during grade change.
Publisher: Elsevier BV
Date: 12-2002
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 07-2020
Publisher: Springer Science and Business Media LLC
Date: 09-02-2017
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.443.146
Abstract: Using finite element method (FEM), the results of bending conditions of the intermediate plate at the bending rolls of a coilbox between the roughing and finishing stands in a hot strip mill were obtained. The intermediate plate was coiled in a coilbox, which effectively overcame the problem of temperature drop by reducing surface area exposed to radiant heat loss during the waiting period. Different states of the plate in the coilbox were simulated by FEM, and the mathematical model of the bending rolls was established, which was in accord with the simulation results that the plate was coiled. As the bending shape of the front end of the intermediate plate is crucial to coiling process, the curvatures of the plate were predicted through FEM. In addition, the roll diameter and arrangement affect the optimum curvature, thus the parameters for bending rolls were determined without many adjustments. The developed bending model has been applied to actual coilbox in plant.
Publisher: EDP Sciences
Date: 2016
Publisher: Elsevier BV
Date: 02-2013
Publisher: Wiley
Date: 30-09-2015
Publisher: Elsevier BV
Date: 05-2021
Publisher: SAGE Publications
Date: 03-10-2018
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 2015
Publisher: Trans Tech Publications Ltd.
Date: 09-02-2008
Publisher: Wiley
Date: 19-11-2014
Abstract: Discharge-stream emergency short-stay units (ESSU) improve ED and hospital efficiency. Age of patients and time of hospital presentations have been shown to correlate with increasing complexity of care. We aim to determine whether an age and time cut-off could be derived to subsequently improve short-stay unit success rates. We conducted a retrospective audit on 6703 (5522 inclusions) patients admitted to our discharge-stream short-stay unit. Patients were classified as appropriate or inappropriate admissions, and deemed successful if discharged out of the unit within 24 h and failures if they needed inpatient admission into the hospital. We calculated short-stay unit length of stay for patients in each of these groups. A 15% failure rate was deemed as acceptable key performance indicator (KPI) for our unit. There were 197 out of 4621 (4.3%, 95% CI 3.7-4.9%) patients up to the age of 70 who failed admission to ESSU compared with 67 out of 901 (7.4%, 95% CI 5.9-9.3%, P 70 years of age have higher rates of failure after admission to discharge-stream ESSU. Although in appropriately selected discharge-stream patients, no age group or time-band of presentation was associated with increased failure rate beyond the stipulated KPI.
Publisher: Elsevier BV
Date: 02-2004
Publisher: Springer Science and Business Media LLC
Date: 11-01-2020
Publisher: Elsevier BV
Date: 06-2020
Publisher: SAGE Publications
Date: 18-04-2018
Abstract: This paper provides a computational model for calculating three-directional ball spinning force in accordance with the theory of space analytic geometry. The contact boundary equation of the ball and tube is obtained. By projection, the two-dimensional curve in each coordinate plane is acquired. The projected area of the contact zone in the coordinate plane is calculated through the curve integral. It is assumed that the average pressure of the forming region is nearly equal to that when the steel ball is pressed into the tube. Hence, the unit pressure of the deformation zone is obtained. Then, the spinning component force and total spinning force are calculated. Using a Tu1 thin-walled tube of oxygen-free copper as experimental object, a ball spinning experiment is conducted, the axial spinning components force are tested and the ball spinning force calculation model is verified. Based on deformation rate, backward sliding accumulation and extension and frictional heating, the factors influencing calculation error are analysed at the end of this paper.
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 06-2016
Publisher: Wiley
Date: 16-03-2016
Abstract: Perceived incivility during ED medical phone consultations is poorly researched. We aimed to determine frequency and factors influencing perceived incivility during ED phone consultations. We conducted a prospective self-reported survey of 40 consecutive phone consultations for 21 ED volunteer doctors. Consultations were classified based on the aim of consultation and deemed as 'positive', 'neutral' or 'negative' based on the perceptions of the consulting doctor. Training levels, time bands and specialty data were collected for both consulting and consulted parties. Fifty-seven of 714 included consultations (7.98%, 95% CI 6.2-10.2%) were reported as negative by ED medical staff. Factors associated with significant incidence of negative grading of consultation involved requests for investigations (19.3% vs 5.3%, P 4 (9.1% vs 3.8%, P < 0.01) and those involving radiology specialty (18% vs 5.32%, P < 0.01). The risk was lower when the consulted professional was a specialist medical practitioner as compared to specialist trainee (4.1% vs 9.4%, P = 0.02). Multiple logistical modelling suggests that female (adjusted OR 2.4, 95% CI 1.1-5.2) medical staff are more likely to report perceived incivility during ED phone consultations. Perceived incivility occurs infrequently during ED phone consultations. ED female medical staff are at an increased risk of perceived incivility during phone consultations with non-ED medical professionals. Health organisations should actively pursue programmes to investigate the occurrence of incivility during healthcare consultations and implement programmes to mitigate the risk of developing a negative workplace culture.
Publisher: Springer Science and Business Media LLC
Date: 05-05-2015
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.655-657.1450
Abstract: In cold strip or foil rolling, flatness control is an integral part of modern mill. This paper introduces two typical flatness control systems, pattern recognisation flatness control system and multivariable flatness control. It is found that the latter is effective and has wider application fields. The FEM models of its core parameters, flatness actuator efficiency, are constructed. Influencing factors, such as the rolling force, bending force as well as the tilting force are discussed. Control strategies are proposed for foil rolling. The results demonstrate that the control strategies can reduce flatness error and improve flatness quality.
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.206
Abstract: The demand of thin gauge strip with good quality such as the strip shape and surface finish is significantly increasing. In this study, finite element model of the strip shape during cold rolling of thin strip in asymmetrical rolling was developed, and the finite element simulation of the thin strip shape has been carried out in LS-DYNA. The effects of reduction and speed ratio on the strip shape and profile and the strip edge drop have been obtained. The developed finite element model has been verified with the experimental data. The obtained results are applicable to the control of the rolled thin strip shape in rolling practice.
Publisher: Trans Tech Publications, Ltd.
Date: 04-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.500.403
Abstract: A well-defined boundary condition is important for generating an accurate model for simulating metal forming process. It is important to characterize the features of the oxide scale in hot rolling of stainless steel strip. Short time oxidation tests in humid air with water vapor content of 7.0 vol. % were carried out using Gleeble 3500 thermo-mechanical simulator. The deformation, surface morphology of oxide scale, and the friction in hot rolling were studied by conducting hot rolling tests. The results show that the surface roughness decreases with an increase of reduction. The effect of oxide scale on friction and surface roughness transfer in hot rolling depends on oxide scale generated during reheating. When reheating time is increased, the average thickness of oxide scale increases and a relatively rough surface was obtained after hot rolling. Thick oxide scale of 301 steel shows the high lubricative effect.
Publisher: Trans Tech Publications, Ltd.
Date: 12-11-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.217-219.1928
Abstract: The process of twin-roll casting including pouring, solidifying, rolling and cooling can be accomplished in a very short time. Consequently, some important process parameters in the twin-roll casting that are difficult to be obtained in experiment can be acquired using numerical simulation. In this paper, a numerical simulation based on a 2D finite element model of vertical twin-roll strip casting of magnesium alloy has been conducted, and the thermal stress fields are significantly discussed. The influences of key process parameters consisting of submerged nozzle depth and nozzle spray angle have been studied. The thermal cracks on the surface of the strip are analysed according to the thermal stress distribution.
Publisher: Trans Tech Publications, Ltd.
Date: 09-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.565.650
Abstract: A cast iron/low carbon steel sandwich-structured bimetal fabricated through composite casting, followed by hot rolling and hot compression (40% reduction) in a vacuum, and water quenched using Gleeble 3500 thermomechanical simulator. The microstructure of a predominantly martensitic structure is transferred to a matrix with an amount of austenite. The measured results show that the macro-hardness is significantly lower due to the evolution of matrix. A considerable amount of secondary carbides were precipitated from the matrix. This study also shows that a significant difference in the value of coefficient of friction (COF) at the end when hot rolling (HR) was tested under three sets of sliding wear conditions, while those for hot rolling and heat treatment (HT) tends to be merged. An increased wear resistance of interfacial zone is expectable.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Informa UK Limited
Date: 05-03-2017
Publisher: Elsevier BV
Date: 02-2020
Publisher: Springer Science and Business Media LLC
Date: 20-03-2013
Publisher: Bentham Science Publishers Ltd.
Date: 05-2013
DOI: 10.2174/1871520611313050007
Abstract: Mushrooms have been consumed for their health benefits for thousands of years in China, and the main active component was recently identified as beta-glucan. The immune-stimulating effect of beta-glucans has been well studied, and several beta-glucan receptors have been identified on the surface of immune cells. In addition, mushroom extracts with high levels of beta-glucans have also been shown to have direct cytotoxic effects on cancer cells, and beta-glucans are used for the treatment of cancer. This review summarizes the use of beta-glucans in colon cancer. Evidence has supported the idea that beta-glucans can decrease the size of xenografted colon cancer tumors via the stimulation of the immune system and direct cytotoxicity. Beta-glucans can also have synergistic effects with chemotherapeutic agents and other immune stimulators, and an innovative strategy is to use beta-glucans to deliver nanoparticles containing chemotherapeutic agents to the site of the colon cancer and, thus, improve the therapeutic efficacy.
Publisher: Inderscience Publishers
Date: 2007
Publisher: Elsevier BV
Date: 04-2000
Publisher: Trans Tech Publications, Ltd.
Date: 12-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.415-417.853
Abstract: The influence of the coiling temperature, ranging from 550 to 570°C, on the morphology and the phase composition of the oxide scale formed on the microalloyed low carbon steel for automobiles after hot strip rolling was investigated. Physicochemical characteristics of the oxide scales were examined and their formation mechanism was discussed. Thickness of the oxide scale is in the range of 8-11µm and decreases with a decrease of coiling temperature. The microstructure and phase composition, XRD analysis shows a large amount of magnetite (Fe 3 O 4 ) and some sparse hematite (Fe 2 O 3 ) exist on the surface of hot rolled strip when the coiling temperature reduces from 570 to 550°C. The coiling temperature substantially affects the internal microstructure and magnetite phase.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.JCIS.2017.08.033
Abstract: Tissue and biomedical engineering fields are in constant mutation and in searching for innovative processing techniques capable to tailor the material properties. In this work, poly(l-lactic acid) (PLLA) and elastomeric poly(glycerol sebacate) (PGS) were dissolved in the same solvents and electrospun together, in a single needle system. A core-shell structure where the hydrophilic PGS was placed onto the surface of the hydrophobic PLLA fibre was obtained for elastomeric concentrations up to 25wt%. It was found that the PLLA:PGS blends are immiscible and the blends present the melting temperatures of the in idual polymers. Moreover, their surface properties were deeply influenced by the presence of the PGS, and a superhydrophilic membrane was obtained, after PGS curing at 120°C for 48h. When the concentration of PGS is up to 25wt%, the blend's Young modulus decreases from ∼35.9±7.1 to 7.5±1.4MPa and a twofold improvement in the s le stretchability was observed, compared with the pristine PLLA electrospun s les. Finally, in vitro hypothalamus A59 nerve cell culture shows that the core-shell electrospun s les enhanced cell adhesion and proliferation, suggesting that these developed materials have great potentials for nerve regeneration and biomedical engineering applications.
Publisher: EDP Sciences
Date: 2018
DOI: 10.1051/MATECCONF/201819011001
Abstract: Thin strips with varying thicknesses (TSVTs) produced by micro flexible rolling have wide applications in erse micro manufacturing areas such as micro electromechanical systems (MEMS) and micro system technologies (MST). TSVTs consist of three regions based on different thicknesses, i.e. the thicker, the transition and the thinner zones. Among them, the transition zone plays a key role in evaluating the quality of TSVTs. In the current work, thin 1060 aluminium alloy strips were flexibly rolled under various thickness ratios followed by annealing treatment. The influences of annealing temperature on the microstructural evolution and hardness variation of the transition zone of TSVTs were investigated. The results reveal that the recrystallisation has happened after annealing at 400 °C for 30 min, which induces fine and homogeneously-distributed grains in both of the thinner and transition zones. Only moderate increase in hardness is found from the thicker to the thinner zones after annealing treatment.
Publisher: Iron and Steel Institute of Japan
Date: 15-07-2019
Publisher: Wiley
Date: 12-2010
DOI: 10.1111/J.1742-6723.2010.01349.X
Abstract: To determine whether CO₂ GAP [(a-ET) PCO₂] value differs consistently in patients presenting with shortness of breath to the ED requiring ventilatory support. To determine a cut-off value of CO₂ GAP, which is consistently associated with measured outcome and to compare its performance against other derived variables. This prospective observational study was conducted in ED on a convenience s le of 412 from 759 patients who underwent concurrent arterial blood gas and ETCO₂ (end-tidal CO₂) measurement. They were randomized to test s le of 312 patients and validation set of 100 patients. The primary outcome of interest was the need for ventilatory support and secondary outcomes were admission to high dependency unit or death during stay in ED. The randomly selected training set was used to select cut-points for the possible predictors that is, CO₂ GAP, CO₂ gradient, physiologic dead space and A-a gradient. The sensitivity, specificity and predictive values of these predictors were validated in the test set of 100 patients. Analysis of the receiver operating characteristic curves revealed the CO₂ GAP performed significantly better than the arterial-alveolar gradient in patients requiring ventilator support (area under the curve 0.950 vs 0.726). A CO₂ GAP ≥10 was associated with assisted ventilation outcomes when applied to the validation test set (100% sensitivity 70% specificity). The CO₂ GAP [(a-ET) PCO₂] differs significantly in patients requiring assisted ventilation when presenting with shortness of breath to EDs and further research addressing the prognostic value of CO₂ GAP in this specific aspect is required.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.622-623.964
Abstract: A novel microforming process - Micro Cross Wedge Rolling (MCWR) has been developed, which is promising for fabricating micro stepped components used in micro electro-mechanical systems. Numerical simulations have been established and the effect of geometrical and process parameters such as forming angle α , stretching angle β and reduction ΔA have been studied. Micro stepped components have been fabricated successfully on a MCWR testing rig by adopting flat wedge tools. The effects of initial surface roughness of tool, grain size and cross section area reduction on surface morphology have been assessed quantitatively.
Publisher: MDPI AG
Date: 27-10-2020
DOI: 10.3390/LUBRICANTS8110096
Abstract: Eco-friendly and low-cost water-based nanolubricants containing rutile TiO2 nanoparticles (NPs) were developed for accelerating their applications in industrial-scale hot steel rolling. The lubrication performance of developed nanolubricants was evaluated in a 2-high Hille 100 experimental rolling mill at a rolling temperature of 850 °C in comparison to that of pure water. The results indicate that the use of nanolubricant enables one to decrease the rolling force, reduce the surface roughness and the oxide scale thickness, and enhance the surface hardness. In particular, the nanolubricant consisting of 4 wt % TiO2, 10 wt % glycerol, 0.2 wt % sodium dodecyl benzene sulfonate (SDBS) and 1 wt % Snailcool exhibits the best lubrication performance by lowering the rolling force, surface roughness and oxide scale thickness by up to 8.1%, 53.7% and 50%, respectively. The surface hardness is increased by 4.4%. The corresponding lubrication mechanisms are attributed to its superior wettability and thermal conductivity associated with the synergistic effect of rolling, mending and laminae forming that are contributed by TiO2 NPs.
Publisher: Elsevier BV
Date: 10-2020
Publisher: Trans Tech Publications, Ltd.
Date: 11-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.773-774.70
Abstract: Controlling cold strip profile is a difficult and significant problem has been found in industry during thin strip rolling. At present choosing the new type of strip rolling mill is the one of main methods to control the strip shape quality in cold rolling. The influences of rolling process parameters such as the work roll cross angle and work roll shifting on the strip shape and profile of thin strip are recognised throughout this study. The results show that the roll crossing and shifting is efficient way to control the strip shape. The increase of the work roll crossing angle would lead to improve the strip profile significantly by decreasing the exit strip crown and edge drop. The strip profile would be enhanced if the axial roll shifting was increased. Moreover, the total rolling force was analysed in detail by changing the roll cross angle and axial shifting roll.
Publisher: Springer Science and Business Media LLC
Date: 22-08-2019
Publisher: Elsevier BV
Date: 02-2021
Publisher: Iron and Steel Institute of Japan
Date: 2000
Publisher: Elsevier BV
Date: 10-2018
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.652-654.2465
Abstract: Quantitative investigation is made on the elemental segregation in different zones of a heavy microalloyed cast steel by energy dispersive X-ray spectroscopy. It is demonstrated that C shows serious segregation tendency than that of Mn and Si, and the degree of C segregation in the surface zone is higher than that in the central zone. C enrichment is generally observed at both dendrite arm and grain boundaries, and more C segregation at dendrite arm boundary in contrast to that at grain boundary is found in this steel. The distribution of C concentration shows a decreased trend from root to tip along the dendrite arm boundary. The C concentration at trigeminal boundary intersection shows higher level than that at other position of the grain boundaries.
Publisher: American Society of Mechanical Engineers
Date: 15-11-2013
Abstract: A novel forming method “micro hydromechanical deep drawing (MHDD)” is focused to improve the tribological property and forming limit. In this study, a theoretical model for MHDD is developed to investigate the size effect on deformation behavior in micro hydromechanical deep drawing. The effects of fluid pressure, the difference of friction coefficients at inner pockets and outer pockets are considered in the investigation on the size effect of tribological property. The friction force decreases as the scale factor decreases in MHDD process. It is also found that the tribological property in micro scale can be improved by applying the fluid pressure. The forming limit decreases as the relative punch diameter increases. However, it is clarified that the forming limit can be improved by decreasing the friction force in MHDD.
Publisher: Springer Science and Business Media LLC
Date: 13-10-2017
Publisher: Elsevier BV
Date: 08-2984
Publisher: Springer Science and Business Media LLC
Date: 21-06-2019
Publisher: Wiley
Date: 25-09-2020
Publisher: Springer Science and Business Media LLC
Date: 06-2011
Publisher: MDPI AG
Date: 29-10-2019
DOI: 10.3390/MA12213536
Abstract: Almost all copper in scrap steel is recovered, so research on copper-bearing steel has profound practical significance. The surface enrichment of copper occurs in all copper-bearing steels studied in this paper after being heated at high temperature. In-situ oxidation-induced copper coatings were discovered on the descaled copper-bearing steels after heating at around 1150 °C for 2 h in air. Scattered copper precipitates in or under rust after heating at a lower temperature. A new concept was created using in-situ composites prepared by direct oxidation of matrix, and there was no bonding problem found between the coating and the matrix. The enrichment form of copper in steel is related to the oxidation rate, oxidation time, heating temperature and copper content.
Publisher: Trans Tech Publications, Ltd.
Date: 02-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.887-888.1133
Abstract: Micro hydroforming has an ability to manufacture complex 3D micro parts at a high production rate and has drawn increasing attentions. Brief understanding of macro hydroforming, for instance, deep drawing, is necessary to understand the principle of micro hydroforming. Then, special phenomena, such as size effects, occurred at micro scale are discussed and the related theories explaining these phenomena are introduced. Based on the similarities and differences between micro and macro hydroforming, experiments and simulation which consider the size effects are reviewed.
Publisher: Wiley
Date: 09-09-2013
Abstract: The study aims to determine the interpretation accuracy of computed tomography of the kidneys, ureters and bladder (CT-KUB) by emergency physicians (EPs) compared with the formal radiology report, as the reference standard, in patients with suspected acute urinary tract calculous disease. A s le of 20 consecutive CT-KUB scans for suspected acute calculous disease was compiled from the medical imaging department of an adult tertiary teaching hospital. Ten EPs with a minimum of 2 years' experience post-Fellowship interpreted each scan using a template form. The total s le of 200 reports by EPs was compared with the formal radiology report for agreement in detecting renal tract stones, signs of obstruction and other clinical findings. Interrater agreement and the kappa statistic were used for comparative data analysis. There was a high level of agreement (%, kappa value) between EPs and radiologists for the detection of large (≥5 mm) calculi (94.5%, κ 0.89), signs of obstruction (93%, κ 0.86) and clinically significant findings (90%, κ 0.78). The level of agreement was low for the detection of small (<5 mm) calculi (79%, κ 0.48) and clinically non-significant findings (67.5%, κ 0.33). EPs can accurately detect clinically significant acute calculous disease and signs of obstruction on CT-KUB, allowing for ongoing acute management and early disposition of the patient. However, their findings should be verified against the formal radiology report when available.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: National Library of Serbia
Date: 2021
Abstract: As heavy industry develops, large amounts of tilting-pad journal bearings are widely used in advanced technology and key equipment. So, it has become a hot research direction to ensure the stable operation of tilting-pad journal bearings by using multiphase lubricating oil. The aim of the present research was to clarify whether using the multiphase lubricating oil has a positive effect on the performance of the bearings. The approach is based on computational multiphase fluid dynamics and finite-element method. Reynolds averaged equations of multi-phase flow was applied to computation for improving the accuracy. The change of loading capacity of oil film was studied with CFD simulation under particles added to the lubricating oil. The results indicate that the bearing capacity of bearing increases when the particle content, diameter, and density increase. The performance of bearing becomes better when the multiphase lubricating oil is applied in the oil film of bearing. The implications of these results are that the development of multiphase lubricating oil has important practical significances.
Publisher: Elsevier BV
Date: 02-2014
Publisher: Springer Science and Business Media LLC
Date: 13-10-2020
Publisher: Elsevier BV
Date: 06-2016
Publisher: Trans Tech Publications, Ltd.
Date: 04-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.680.113
Abstract: A new type of gradient boron alloyed composite material, containing boron alloyed core layers and stainless steel coatings around the core, were designed and prepared by composite casting and hot rolling. The evolution of microstructures, phases and precipitations, as well as their influence on hot rolling process and performance are investigated. A mixture of austenitic matrix and uniformly distributed borides are obtained in the hot rolled stainless steel with 2-2.5 % boron, while massive borides are in the length of 80-120 μm together with micro gaps at the interface between the borides, and the matrix is remained after hot rolling for the core layers with higher boron contents. Hot deformation would be hindered since more precipitations of these orthorhombic or tetragonal phases occur with an increase of the boron concentration in the core layers.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Springer Science and Business Media LLC
Date: 22-03-2019
Publisher: Elsevier BV
Date: 10-2021
Publisher: Springer Science and Business Media LLC
Date: 28-12-2014
Publisher: IOP Publishing
Date: 10-07-2019
Publisher: IOP Publishing
Date: 12-2017
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.622-623.943
Abstract: A novel microforming process - Micro Cross Wedge Rolling (MCWR) has been developed. It is a very promising technology in the field of microforming due to its advantages such as high product rate and minimised material consumption. How to control geometrical accuracy of the produced micro parts is one of the major challenges in the development of microforming technology. Geometrical accuracy was still concentrated in term of springback. When the wedge tools loads are removed after forming step, a portion of the deformation recovers, which causes a change in the shape of micro parts. In other word, springback happens, which should be determined and controlled especially in microforming technology. A series of MCWR experiments of pure copper and aluminium have been carried out using the machine designed by authors in this study. Cylindrical workpieces were deformed into stepped shafts with cross-sectional area reductions of 35, 52.73 and 75%. Corresponding finite element simulation has also been conducted in consideration of the size effect on the material flow. The springback was proposed to account for the geometrical error of micro products. The effect of grained heterogeneity on the height of surface asperity after rolling was assessed quantitatively. Keywords: Micro cross wedge rolling, Size effect, Dimensional accuracy, Springback
Publisher: BMJ
Date: 16-05-2014
Publisher: Elsevier BV
Date: 06-2017
Publisher: Trans Tech Publications, Ltd.
Date: 10-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.145.482
Abstract: In tension leveling, elongation is determined by a combination of tension and deformation curvature, so how to set up optimization of the processing parameters has been emphasized by researchers. In this paper, the deformation work in tension leveling was introduced. According to the calculation used in a tension leveler, the tension and deformation curvature which results in less deformation work under a certain elongation is presented. The method can determine the leveling processes parameters for different strip with various properties and sizes.
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 03-2012
Publisher: Springer Science and Business Media LLC
Date: 04-2017
Publisher: Trans Tech Publications, Ltd.
Date: 07-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.861.201
Abstract: To obtain a low cost, environmentally friendly and effective lubricant, a novel nanoTiO 2 additive oil-in-water (O/W) lubricant for hot steel rolling has been developed. Based on the contact angle, tribological and hot rolling tests, the performance of the nanoTiO 2 additive O/W lubricants was evaluated and discussed. The results show that the strongest adhesion force between the nanoTiO 2 additive O/W lubricant and the work roll is obtained after addition of 4% nanoTiO 2 additive in the 1% O/W lubricant. The nanoTiO 2 nanoparticles can reduce coefficient of friction (COF) and rolling force, and enhance the surface quality of the hot-rolled product. The lubrication mechanism of nanoTiO 2 additive O/W-based lubricant has been proposed.
Publisher: IEEE
Date: 12-2009
Publisher: Trans Tech Publications, Ltd.
Date: 15-11-2017
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.879.2274
Abstract: Micro hydro deep drawing is a promising technology to fabricate micro metal products with complex 3D shapes. However, the size effects in the micro hydro deep drawing become considerable and significantly influence shape accuracy of drawn cups. In this study, a Voronoi micro scale simulation model was developed to consider the size effects of SUS304 foils. A surface layer model was additionally applied in the simulation to further explain the size effects. The micro hydro deep drawing experiments were conducted with annealed SUS304 foils and the drawn cups were examined. The wrinkling phenomenon was generally aggravated with the hydraulic pressure. Simulation results also show that the high hydraulic pressure does not improve the shape accuracy of the drawn cups as that in the normal scale hydro deep dawning process does. The simulation results are in accordance with the experimental results.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Trans Tech Publications, Ltd.
Date: 05-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.239-242.3377
Abstract: Online roller punching is required for many cold forming sectional steel products, and the productive efficiency of punching is significantly affected by uncoordinated speed between the traditional punching and the cold roll forming. Based on the analysis of the mechanical structure and the mould structure of the equipment, a new roller punching equipment has been developed for continuous high-speed punching process of steel strips with thickness of less than 1mm.
Publisher: Research Square Platform LLC
Date: 30-08-2021
DOI: 10.21203/RS.3.RS-838166/V1
Abstract: Micro deep drawing is a promising manufacturing method to produce the hollow, thin walled, cup or box like products at micro scale. Forming velocity can affect the products’ quality significantly due to the size effect, and this effect can be various with different thickness material. In this study, 30, 40, and 50 µm thickness stainless steels were annealed at 950 °C for 2 min under protection of argon gas ambient respectively. These different thickness steels were utilized in the micro deep drawing with different forming velocities. The experimental results show that, the profile accuracy and surface quality of the micro product are affected by changing the forming velocity with different thickness blanks. The micro cup has a less indentation area at the bottom and becomes rounder and more symmetrical with a thicker blank. Besides, the wrinkling phenomenon turns distinct with a thinner blank, and the earing becomes more significantly when increasing the drawing velocity or decreasing the blank thickness. When the drawing velocity or blank thickness increases, the surface of the micro cup becomes smooth and even. The experimental results are in good agreement with the simulation results, which confirms the developed finite element simulation model is applicable.
Publisher: Wiley
Date: 26-12-2022
DOI: 10.5694/MJA2.51828
Publisher: Elsevier BV
Date: 06-2022
Publisher: Springer Science and Business Media LLC
Date: 11-07-2018
Publisher: Elsevier BV
Date: 02-2019
Publisher: Trans Tech Publications, Ltd.
Date: 09-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.395-396.273
Abstract: Oxidation characteristics of a microalloyed low carbon steel were investigated by a hot rolling mill combined with acceleration cooling system over the cooling rate range from 20 to 70°C/s. The effects of cooling rate after hot rolling on microstructure and phase composition of oxide scale were examined. The results showed that the increase of the cooling rate has a significant influence on the decrease of the grain size and surface roughness of oxide scale. A higher cooling rate promotes the formation of retain wustite and primary magnetite precipitation while suppression of eutectoid α-iron precipitates. This provides the possibility to enhance potential contribution of magnetite precipitates with preferable ductility, and hence fabricates a desired oxide-scale structure under continuous post cooling conditions considering a suitable cooling rate.
Publisher: Elsevier BV
Date: 06-2015
Publisher: Springer Science and Business Media LLC
Date: 28-06-2011
Publisher: Trans Tech Publications Ltd.
Date: 09-02-2008
Publisher: MDPI AG
Date: 11-05-2021
DOI: 10.3390/MA14102478
Abstract: The hot deformation behavior of a newly designed Fe–5Mn–3Al–0.1C (wt.%) medium manganese steel was investigated using hot compression tests in the temperature range of 900 to 1150 °C, at constant strain rates of 0.1, 1, 2.5, 5, 10, and 20 s−1. A detailed analysis of the hot deformation parameters, focusing on the flow behavior, hot processing map, dynamic recrystallization (DRX) critical stress, and nucleation mechanism, was undertaken to understand the hot rolling process of the newly designed steel. The flow behavior is sensitive to deformation parameters, and the Zener–Hollomon parameter was coupled with the temperature and strain rate. Three-dimensional processing maps were developed considering the effect of strain and were used to determine safe and unsafe deformation conditions in association with the microstructural evolution. In the deformation condition, the microstructure of the steel consisted of δ-ferrite and austenite in addition, there was a formation of DRX grains within the δ-ferrite grains and austenite grains during the hot compression test. The microstructure evolution and two types of DRX nucleation mechanisms were identified it was observed that discontinuous dynamic recrystallization (DDRX) is the primary nucleation mechanism of austenite, while continuous dynamic recrystallization (CDRX) is the primary nucleation mechanism of δ-ferrite. The steel possesses unfavorable toughness at the deformation temperature of 900 °C, which is mainly due to the presence of coarse κ-carbides along grain boundaries, as well as the lower strengthening effect of grain boundaries. This study identified a relatively ideal hot processing region for the steel. Further exploration of hot roll tests will follow in the future.
Publisher: MDPI AG
Date: 03-11-2020
DOI: 10.3390/MA13214933
Abstract: Static corrosion experiments were carried out to investigate the corrosion of each kind of component in the rolling oil on the rolled copper foil. The surface morphology and chemical composition of corrosion products were detected by a digital camera, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that the maximum corrosion rate of rolled copper foil in the base stock and friction modifiers (butyl stearate and dodecanol) was close to zero, while that of rolled copper foil in the N-containing borate, phosphate and the fully formulated rolling oil were 0.17, 1.12 and 0.78 mm/a, respectively. The color of rolled copper foil changing from pink into purple-black when corroded in the N-containing borate. The composition of it was mainly CuO and Cu2O with some N-containing borate adsorbed on it. However, the color and composition of the corroded copper foil in the phosphate were similar to that of the original copper foil. It was complicated for the corroded copper foil in the fully formulated rolling oil, which showed characteristics both in the N-containing borate and in the phosphate according to different positions. It indicated that there might be little corrosion for the base stock and friction modifiers on the rolled copper foil. It might mainly be extreme pressure additives (N-containing borate and phosphate) that caused the corrosion of rolled copper foil. There might be competition between N-containing borate and phosphate for the corrosion of rolled copper foil in the fully formulated rolling oil, resulting in a lower corrosion rate compared with that in the phosphate.
Publisher: Trans Tech Publications, Ltd.
Date: 10-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.145.111
Abstract: Flatness imperfections are observed during uncoiling of the hot rolled strip after forced cooling of coils to ambient temperature. This problem is significant in thin strip as free defect was considered in the process. A mathematical model for heat transfer and thermal deformation analysis during cooling of hot rolled coils is developed to explain the phenomenon of post-rolling flatness deterioration, and predict the occurrence and magnitude of the defects. The numerical simulation results obtained in this work were experimentally validated. It is shown, at a low coiling temperature allowing the phase transformation to reach completion, that the axial distribution of the temperature mainly causes the variation of the local thermal stress, and will promote the flatness deterioration.
Publisher: Springer Science and Business Media LLC
Date: 04-11-2017
Publisher: Wiley
Date: 17-11-2021
Abstract: The microstructure of Cr–Mn–Ni–N stainless steel is regulated by a combination of cold deformation and subsequent martensite reversed annealing. The yield strength and tensile strength of the tested steel are greatly improved to 1220 and 1357 MPa, respectively, by conventional heavy cold rolling (66% thickness reduction) and a subsequent annealing process (750 °C for 5 min) relative to those before cold rolling (austenized state) at the same time, the total elongation keeps an appropriate value. The results show that the grain refinement strengthening acts as the primary factor for the strengthening of the tested steels while the precipitation behavior from the M 23 C 6 ‐type carbides is not quite effective. Additionally, different yield phenomena and microstructural evolution for tested steels with 66% thickness reduction annealed at 750 °C with different holding times are systematically analyzed and discussed. Lüders‐like deformation features noticeably appear but become weakening with the longer annealing time. The change in initial free mobile dislocation density is the core cause of the preyield plateau phenomenon.
Publisher: Springer Science and Business Media LLC
Date: 04-2014
Publisher: Wiley
Date: 17-09-2014
Publisher: Wiley
Date: 24-07-2017
Publisher: Trans Tech Publications, Ltd.
Date: 2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.706-709.2517
Abstract: Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during the metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.
Publisher: Elsevier BV
Date: 06-2004
Publisher: Elsevier BV
Date: 11-2014
Publisher: Springer Science and Business Media LLC
Date: 03-01-2017
Publisher: Trans Tech Publications, Ltd.
Date: 2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.706-709.1421
Abstract: In this paper, finite element models of the strip shape during cold rolling of ultra thin strip in both symmetrical and asymmetrical rolling cases have been successfully developed, and the strip shape such as the thickness distribution along the strip width has been obtained. The strip shape and edge drop are discussed under both symmetrical and asymmetrical rolling conditions. Simulation results show that the asymmetrical rolling can reduce strip edge drop dramatically. The work roll edge curve also affects strip shape significantly. The developed finite element model has been verified with the experimental values.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.20964/2019.12.65
Publisher: MDPI AG
Date: 29-09-2019
DOI: 10.3390/MET9101062
Abstract: This study delineates a novel finite element model to consider a pattern of process parameters affecting the forward slip in micro flexible rolling, which focuses on the thickness transition area of the rolled strip with thickness in the micrometre range. According to the strip marking method, the forward slip is obtained by comparison between the distance of the bumped ridges on the roll and that of the markings indented by the ridges, which not only simplifies the calculation process, but also maintains the accuracy as compared with theoretical estimates. The simulation results identify the qualitative and quantitative variations of forward slip with regard to the variations in the reduction, rolling speed, estimated friction coefficient and the ratio of strip thickness to grain size, respectively, which also locate the cases wherein the relative sliding happens between the strip and the roll. The developed grain-based finite element model featuring 3D Voronoi tessellations allows for the investigation of the scatter effect of forward slip, which gets strengthened by the enhanced effect of every single grain attributed to the dispersion of fewer grains in a thinner strip with respect to constant grain size. The multilinear regression analysis is performed to establish a statistical model based upon the simulation results, which has been proven to be accurate in quantitatively describing the relationship between the forward slip and the aforementioned process parameters by considering both correlation and error analyses. The magnitudes of each process parameter affecting forward slip are also determined by variance analysis.
Publisher: Elsevier BV
Date: 11-2004
Publisher: Elsevier BV
Date: 2014
Publisher: Institution of Engineering and Technology (IET)
Date: 11-04-2020
Publisher: Elsevier BV
Date: 05-2018
Publisher: Springer Science and Business Media LLC
Date: 13-11-2018
Publisher: Springer Science and Business Media LLC
Date: 2018
Publisher: Elsevier BV
Date: 12-2001
Publisher: Elsevier BV
Date: 08-2011
Publisher: Springer Science and Business Media LLC
Date: 12-03-2015
Publisher: Elsevier BV
Date: 11-2004
Publisher: Elsevier BV
Date: 11-2004
Publisher: Elsevier BV
Date: 09-2004
Publisher: Elsevier BV
Date: 10-2017
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.JEMERMED.2015.03.005
Abstract: The incidence of cervical spine injuries (CSI) in people over 65 years of age from low-energy mechanisms is far greater than in younger populations. Algorithms and decision rules exist for selection of trauma patients requiring cervical spine imaging. To determine the validity of the NEXUS criteria in the elderly population with low-mechanism injuries. We prospectively conducted computed tomography (CT) imaging in patients > 65 years of age presenting with fall from standing height or less to rule out predefined clinically significant CSI. Eligible patients were prospectively categorized into NEXUS positive or negative. There were 169 patients included in the final analyses. One hundred twenty (71%) patients in the cohort were classified as "NEXUS positive." Eleven patients (6.5% of the cohort) had CSI detected on CT imaging of the cervical spine. Nine patients had clinically significant CSI. The NEXUS decision instrument demonstrated 88.9% sensitivity (50.7-99.4%) and 98% negative predictive value (NPV) (87.8-99.9%) in detecting clinically significant CSI. The NEXUS decision instrument demonstrated 81.8% sensitivity (47.8-96.8%) and 95.9% NPV (84.9-99.3%) in detecting any CSI. In our study, the NEXUS decision instrument was not a valid tool to rule out imaging for patients > 65 years of age presenting after a fall from standing height or less. We advocate the liberal use of CT imaging of the cervical spine in this cohort of patients to rule out cervical spine injury.
Publisher: Springer Science and Business Media LLC
Date: 19-04-2021
DOI: 10.1186/S10033-021-00556-5
Abstract: In the present work, austenitic stainless steel (ASS) 304 foils with a thickness of 50 µm were first annealed at temperatures ranging from 700 to 1100 ℃ for 1 h to obtain different microstructural characteristics. Then the effects of microstructural characteristics on the formability of ASS 304 foils and the quality of drawn cups using micro deep drawing (MDD) were studied, and the mechanism involved was discussed. The results show that the as-received ASS 304 foil has a poor formability and cannot be used to form a cup using MDD. Serious wrinkling problem occurs on the drawn cup, and the height profile distribution on the mouth and the symmetry of the drawn cup is quite non-uniform when the annealing temperature is 700 ℃. At annealing temperatures of 900 and 950 ℃, the drawn cups are both characterized with very few wrinkles, and the distribution of height profile, symmetry and mouth thickness are uniform on the mouths of the drawn cups. The wrinkling becomes increasingly significant with a further increase of annealing temperature from 950 to 1100 ℃. The optimal annealing temperatures obtained in this study are 900 and 950 ℃ for reducing the generation of wrinkling, and therefore improving the quality of drawn cups. With non-optimized microstructure, the distribution of the compressive stress in the circumferential direction of the drawn foils becomes inhomogeneous, which is thought to be the cause of the occurrence of localized deformation till wrinkling during MDD.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 02-2021
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1017.147
Abstract: The dry sliding wear behaviour of the full pearlite in a novel bimetal consisting of low carbon steel and hypoeutectoid steel has been studied by means of pin-on-disc type wear tests at room temperature. Thermomechanical treatments were performed on the bimetallic s les to obtain different interlamellar spacings. It was found that interlamellar spacing decreased with an increase in plastic strain to a great extent initially and followed by a lower extent of decrease. This decrease not only increases the hardness and strain hardening capacity of the fully pearlitic microstructure, but also is in favor of stabilizing the friction coefficient during sliding process. The observations of wear tracks show that delamination dominated the wear process when interlamellar spacing is higher than 200 nm, while pronounced oxidational wear occurred with interlamellar spacing below 200 nm.
Publisher: Trans Tech Publications, Ltd.
Date: 06-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.941-944.2414
Abstract: In the present work, detailed studies were made on the transformation characteristics, microstructure and mechanical properties of heavy shell ring (HSR) in the spray cooling process. The spray cooling device of HSR was designed. The 2.25Cr1Mo0.25V steel used in production of HSR for hydrogenation reactor was selected as the testing material. The simulation of spray cooling of HSR was carried out on ABAQUS. The constitutive model and continuous cooling transformation (CCT) diagram of 2.25Cr1Mo0.25V were determined. CCT diagram, metallograph and SEM results show that the bainite forms throughout the cooling rate range from 0.5 to 10 ℃/s, and martensite begins to be produced by increasing the cooling rate higher than 60℃/s when the cooling rate is 10 ℃/s, with the increase of the deformation degrees, the ferrite grain size becomes small, the yield strength and tensile strength increase, the elongation decrease, So it is good for refining the grain to increase the deformation. The yield strength, tensile strength and elongation were obtained under different cooling technology.
Publisher: Springer Science and Business Media LLC
Date: 11-2020
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 09-2003
Publisher: Informa UK Limited
Date: 04-2015
Publisher: Springer Science and Business Media LLC
Date: 08-02-2021
Publisher: Chinese Journal of Mechanical Engineering
Date: 2020
Publisher: Trans Tech Publications, Ltd.
Date: 10-2020
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.311.12
Abstract: In order to make micro composite drills (Fig. 1), cemented tungsten carbide (WC-10Co) and high strength (AISI 4340) steel were successfully bonded by hot compaction diffusion bonding at a low temperature. The effects of holding time, pressure and temperature on microstructure and mechanical properties of the sintered carbides and bonding strengths of the bimetallic composites were examined, and a transitional layer was found at the interface as a result of elemental inter-diffusion. The optimal bonding parameters were determined to achieve the maximum bonding strength of 226 MPa of the WC-10Co/AISI 4340 steel joints, which is helpful in producing micro composite drills. Microforming is introduced to produce lighter and more energy effective products. In this study, Magnesium-Lithium (Mg-Li) alloy, new material in microscale, was chosen to superior formed micro-cup due to its ultralight weight with outstanding ductility. The dry and oil lubrication conditions were chosen as benchmarks to investigate effects of a novel oil-based nanoparticle lubricant in micro deep drawing (MDD) process of Mg-Li alloy. Finite Element (FE) modelling was conducted and the simulation results of the drawing force were in a good agreement with the experimental results. The formed cup quality with consideration on the surface roughness has been extensively evaluated and the results illustrated the quality improvement was substantial.
Publisher: Iron and Steel Institute of Japan
Date: 15-10-2018
Publisher: Springer Science and Business Media LLC
Date: 14-10-2020
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 04-2013
Publisher: Springer Science and Business Media LLC
Date: 26-07-2019
Publisher: Springer Science and Business Media LLC
Date: 26-10-2015
Publisher: Trans Tech Publications, Ltd.
Date: 12-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.418-420.897
Abstract: Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.
Publisher: MDPI AG
Date: 15-09-2021
DOI: 10.3390/MET11091462
Abstract: Using a period immersion wet/dry cyclic corrosion test, in-situ copper-coated steels prepared by corroding copper-bearing steels were investigated in this study. The steel with a higher copper content ( %) has a higher initial corrosion rate due to its obvious two-phase microstructure. The corrosion rates of all copper bearing steels tend to be stable after a certain time of corrosion. A copper-rich layer is formed between the matrix and the rust layer, which is due to the diffusion of copper from the rust layer to the metal surface. The copper’s stability under this corrosion condition led to the formation of a thin copper-rich film, which was uncovered after removing the rust by choosing appropriate descaling reagents. The copper coating was generated from the matrix itself during the corrosion process at 25 °C, which provided a new approach for producing in-situ composite materials without any bonding defect. It is found that the corrosion rate, corrosion time, and copper content in steel all affect the formation of copper-rich layer. In addition to the noble copper surface, the electrochemical corrosion test results show that the corrosion resistance of copper-coated steel has been significantly improved.
Publisher: Inderscience Publishers
Date: 2017
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 09-2003
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.443.9
Abstract: Strip shape is an important factor affecting the strip quality significantly during cold rolling of thin strip. In the paper, finite element simulation models of the strip shape in cold rolling for both symmetrical and asymmetrical rolling cases were successfully developed. The strip edge drop and the effect of the rolling force on the strip shape (the thickness distribution along the strip width) have been obtained. The developed finite element model has been verified with the experimental value, which shows they are in good agreement. The obtained results are applicable to control the rolled thin strip shape during cold rolling practice.
Publisher: Elsevier BV
Date: 07-2011
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 11-2001
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4806948
Publisher: Elsevier BV
Date: 09-2003
Publisher: Elsevier BV
Date: 05-2005
Publisher: Springer Science and Business Media LLC
Date: 05-2015
Publisher: CRC Press
Date: 12-07-2017
Publisher: Elsevier BV
Date: 05-2005
Publisher: Elsevier BV
Date: 11-2020
Publisher: Inderscience Publishers
Date: 2011
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 2016
Publisher: Inderscience Publishers
Date: 2009
Publisher: Inderscience Publishers
Date: 2009
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 04-2022
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 2018
Publisher: Trans Tech Publications, Ltd.
Date: 03-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.97-101.71
Abstract: In this paper, a new method considering the combination of tension and deformation curvature which results in less deformation energy under a certain elongation is presented at the first time. The calculation results show that when the elongation is less than 1 %, the tension which is about 1/6 yield stress will consume less energy. If the tension decreases from 1/4 to 1/8 yield stress, the deformation energy of strip with yield stress of greater than 450 MPa decreases significantly. This study can help determine the processes parameters of strip tension levelling effectively.
Publisher: AIP Publishing LLC
Date: 2014
DOI: 10.1063/1.4897740
Publisher: Elsevier BV
Date: 12-2015
Publisher: IEEE
Date: 05-2007
Publisher: IEEE
Date: 05-2007
Publisher: MDPI AG
Date: 10-09-2021
DOI: 10.3390/LUBRICANTS9090089
Abstract: Applying nanomaterials and nanotechnology in lubrication has become increasingly popular and important to further reduce the friction and wear in engineering applications. To achieve green manufacturing and its sustainable development, water-based nanolubricants are emerging as promising alternatives to the traditional oil-containing lubricants that inevitably pose environmental issues when burnt and discharged. This review presents an overview of recent advances in water-based nanolubricants, starting from the preparation of the lubricants using different types of nanoadditives, followed by the techniques to evaluate and enhance their dispersion stability, and the commonly used tribo-testing methods. The lubrication mechanisms and models are discussed with special attention given to the roles of the nanoadditives. Finally, the applications of water-based nanolubricants in metal rolling are summarised, and the outlook for future research directions is proposed.
Publisher: Elsevier BV
Date: 09-2003
Publisher: Springer Science and Business Media LLC
Date: 05-2009
Publisher: MDPI AG
Date: 11-09-2020
DOI: 10.3390/MA13184046
Abstract: Product miniaturization is a trend for facilitating product usage, enabling product functions to be implemented in microscale geometries, and aimed at reducing product weight, volume, cost and pollution. Driven by ongoing miniaturization in erse areas including medical devices, precision equipment, communication devices, micro-electromechanical systems (MEMS) and microsystems technology (MST), the demands for micro metallic products have increased tremendously. Such a trend requires development of advanced micromanufacturing technology of metallic materials for producing high-quality micro metallic products that possess excellent dimensional tolerances, required mechanical properties and improved surface quality. Micromanufacturing differs from conventional manufacturing technology in terms of materials, processes, tools, and machines and equipment, due to the miniaturization nature of the whole micromanufacturing system, which challenges the rapid development of micromanufacturing technology. Against such a background, the Special Issue “Micromanufacturing of Metallic Materials” was proposed to present the recent developments of micromanufacturing technologies of metallic materials. The papers collected in the Special Issue include research articles, literature review and technical notes, which have been highlighted in this editorial.
Publisher: Springer Science and Business Media LLC
Date: 10-2010
Publisher: Inderscience Publishers
Date: 2009
Publisher: Elsevier BV
Date: 12-2002
Publisher: Trans Tech Publications, Ltd.
Date: 12-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.418-420.1698
Abstract: The straightening of curved slab results in a greater straightening strain. During the process of multi-point straightening, the peak value of the straightening strain rate will appear at each straightening point. If the strain rate is too large, the straightening cracks will appear. Solidification and heat transfer of a slab is analyzed and the generation of the solidified shell and the three-dimension temperature field of the slab are calculated by using three-dimensional finite element method (FEM). Based on the finite element analysis of five-point straightening of the curved slab, the strain and strain rate of each straightening point were obtained, which is a base of the analysis of straightening cracks.
Publisher: Elsevier BV
Date: 11-2015
Publisher: Trans Tech Publications, Ltd.
Date: 08-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.325.731
Abstract: In the paper, a crystal plasticity finite element method (CPFEM) model was developed based on ABAQUS to analyse the surface roughness transfer during metal manufacturing. The simulation result shows a good agreement with the experimental result in the flattening of surface asperity, and the surface roughness decreases significantly with an increase of reduction with considering friction effect. Lubrication can delay surface asperity flattening. The effect of surface roughness on produced metal defect (crack) was also studied, and the surface roughness affects the crack initiation significantly in cold strip rolling. In addition, the surface roughness variation along the metal plate width contributes to stress distribution and then inhibition of crack nucleation.
Publisher: Elsevier BV
Date: 10-2020
Publisher: Springer Science and Business Media LLC
Date: 03-01-2022
Publisher: Elsevier BV
Date: 07-2006
Publisher: Trans Tech Publications, Ltd.
Date: 10-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.716.843
Abstract: In hot rolling, metal oxides formed on steel surface can generally be classified as primary, secondary and tertiary oxide scales, corresponding to the reheating stages, the roughing stages and the finishing passes of continuous mills, respectively. The tertiary oxide scale grows into the final products on the hot-rolled steel strip during the finishing rolling and the subsequent cooling down to ambient temperature. We provide here a systematic overview of the oxidation mechanism, microstructure and microtexture development of the tertiary oxide scale. Mechanism of oxidation and Fe 3 O 4 precipitation in tertiary oxide has been given as the fundamental theory. Three main sections has been ided in this review. The first section includes experimental investigations on microstructure evolution from the formation of oxide scale during hot rolling, then through continuous cooling, to Fe 3 O 4 precipitation behaviour in storage cooling of hot-coiled strip. By using electron backscatter diffraction (EBSD) to characterise both the steel substrate and the oxide scale concurrently, the second section has further dealed with the texture-based analysis of oxide scale: phase identification, orientation analysis and coincident site lattice (CSL) boundaries. The third section has provided the general type of crystallographic texture and its evolutions in deformed Fe 3 O 4 and steel substrate. Finally, the upcoming challenges have been addressed in this intriguing and promising research field.
Publisher: Wiley
Date: 29-12-0029
Publisher: Elsevier BV
Date: 10-2012
Publisher: Springer Science and Business Media LLC
Date: 23-07-2015
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 07-2011
Publisher: Elsevier BV
Date: 07-2011
Publisher: Springer Science and Business Media LLC
Date: 13-07-2019
Publisher: Elsevier BV
Date: 06-2008
Publisher: Wiley
Date: 20-05-2013
Abstract: Blood pressure (BP) cuffs are potential vectors for transmission of multi-resistant organisms (MROs). The present study aims to determine MRO colonisation rates in BP cuffs from areas of high patient flow as an assessment of the quality of disinfection and infection control practices. BP cuffs in the ED, high dependency unit (HDU) and operating theatres (OT) were prospectively examined after routine disinfection procedures. Swabs collected from the inner and outer surfaces of BP cuffs during inter-patient intervals were plated onto replicate organism detection and counting, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) chromogenic agar plates to detect rates of bacterial, MRSA and VRE colonisation, respectively. High bacterial colonisation rates were detected in BP cuffs from all three areas. BP cuffs from OT were significantly less colonised compared with cuffs from HDU and ED 76% versus 96% and 100% (P < 0.0001) for inner surfaces and 86% versus 98% and 100% (P < 0.0001) for outer surfaces, respectively. Equivalent or higher bacterial growth was observed on the inner surface compared with outer surface in 54%, 84% and 86% of BP cuffs from OT, HDU and ED, respectively. MRSA was detected in 3 of 150 (2%) swabs collected, but no VRE was detected. Although MRSA and VRE were infrequently isolated, current disinfection and infection control protocols need to be improved given the greater recovery of organisms from the inner compared with outer surfaces of BP cuffs.
Publisher: MDPI AG
Date: 02-07-2018
Publisher: Wiley
Date: 20-08-2018
Abstract: To compare patient satisfaction levels, staff perspectives and the time required using Structured Interdisciplinary Bedside Rounds (SIBR Emory University, Atlanta, GA, USA) versus traditional medical ward rounds (TR) in the ED. We conducted an observational cross-sectional study. Ward rounds were categorised into a modified SIBR and TR at a tertiary ED in Australia according to predefined criteria. We compared the duration of ward rounds, invited patients and staff to complete anonymous questionnaires to compare patient satisfaction and staff perspectives. During the study period, SIBR group took significantly longer time than TR per patient (122 vs 88 s, P < 0.001). Patient questionnaires were completed for 320 encounters (101 SIBR, 219 TR). Patient satisfaction scores across all measured domains were significantly higher in SIBR than in the TR group. Patients often pointed out a lack of communication with medical staff during TR. Based on 131 completed staff questionnaires, nurses reported SIBR to be more useful than TR (nurses 78% vs doctors 44%, P = 0.001). The SIBR group had increased instances of staff introductions to patients (91% vs 66%, P < 0.001) and patients' involvement in discussion of management plans (98% vs 53%, P < 0.01). SIBR only weakly correlated with the overall positive experience in the ED (r = 0.19, P = 0.001). Organisational implementation issues raised through qualitative methods are reported in the paper. Our study highlights the benefits that could be gained through SIBR technique over the TR method. Better workforce and resource planning is needed to support the sustainable implementation of SIBR in ED.
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 09-2007
Publisher: Trans Tech Publications, Ltd.
Date: 03-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.97-101.412
Abstract: Contact friction is of crucial importance for the accurate modelling, optimum design and control of industrial rolling processes. Hot rolling tests were carried out to investigate the deformation of oxide scale and friction during hot rolling of stainless steel 304L. The morphology of oxide scale layer and the surface roughness transfer under the conditions of hot rolling were obtained. The friction condition at the roll-strip interface was determined.
Publisher: Springer Science and Business Media LLC
Date: 20-06-2023
DOI: 10.1186/S43058-023-00452-0
Abstract: Emergency department (ED) overcrowding is a global problem and a threat to the quality and safety of emergency care. Providing timely and safe emergency care therein is challenging. To address this in New South Wales (NSW), Australia, the Emergency nurse Protocol Initiating Care—Sydney Triage to Admission Risk Tool (EPIC-START) was developed. EPIC-START is a model of care incorporating EPIC protocols, the START patient admission prediction tool, and a clinical deterioration tool to support ED flow, timely care, and patient safety. The aim of this study is to evaluate the impact of EPIC-START implementation across 30 EDs on patient, implementation, and health service outcomes. This study protocol adopts an effectiveness-implementation hybrid design (Med Care 50: 217-226, 2012) and uses a stepped–wedge cluster randomised control trial of EPIC-START, including uptake and sustainability, within 30 EDs across four NSW local health districts spanning rural, regional, and metropolitan settings. Each cluster will be randomised independently of the research team to 1 of 4 dates until all EDs have been exposed to the intervention. Quantitative and qualitative evaluations will be conducted on data from medical records and routinely collected data, and patient, nursing, and medical staff pre- and post-surveys. Ethical approval for the research was received from the Sydney Local Health District Research Ethics Committee (Reference Number 2022/ETH01940) on 14 December 2022. Australian and New Zealand Clinical trial, ACTRN12622001480774p. Registered on 27 October 2022.
Publisher: Informa UK Limited
Date: 02-2011
Publisher: Trans Tech Publications, Ltd.
Date: 10-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.148-149.253
Abstract: This paper investigates the effects of normal hot rolling and high rate cooling (NHR+HRC) on microstructure and mechanical properties of the rolled EH 36 hull plate. Double-hit tests were carried out to study the effect of process parameters such as the deformation temperature and soaking time on microstructures of the tested steel, and explore optimal processing parameters. Single-hit compression with various parameters was developed and the microstructures of the tested steel are analyzed to determine the cooling rate and the final cooling temperature of the normal hot rolling and high rate cooling. This study will provide experimental and theoretical base on high-temperature rolling control system. Industrial trial was performed to produce regular products. The results show that the NHR+HRC is an effective and promising method to improve the product quality of high-strength hull plate.
Publisher: American Chemical Society (ACS)
Date: 30-10-2018
Publisher: Elsevier BV
Date: 09-2017
Publisher: Trans Tech Publications, Ltd.
Date: 02-2020
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.830.43
Abstract: High-strength steel is widely applied due to its excellent mechanical properties. However, its high strength in turn brings great difficulties to production and processing such as hot strip rolling owing to the high rolling force, which results in large elastic deformation of roll stack and poses a huge challenge to the control of strip crown and flatness. In this paper, A three-dimensional (3D) elastic-plastic coupled thermo-mechanical finite element (FE) model for hot strip rolling of high-strength steel is developed and then verified experimentally. This model not only calculates the elastic deformation of rolls and plastic deformation of strip simultaneously, but also considers the effect of temperature variation during hot strip rolling. Based on this valid model, the effects of bending force and shifting value of work roll (WR), back-up roll (BR) size, entrance strip crown and rolling force on strip crown have been investigated quantitatively. The results obtained provide valuable guidelines for industrial strip production.
Publisher: MDPI AG
Date: 15-10-2020
DOI: 10.3390/MET10101375
Abstract: A new hot forming process of a hot-rolled 2205 duplex stainless/AH36 low-carbon steel bimetal composite (2205/AH36 BC) was proposed in this study, using the Gleeble 3500 thermal-mechanical simulator and hot bending tools. The deformation characteristics of 2205/AH36 BC were studied by hot tensile tests at temperatures from 950 to 1250 °C and strain rates ranging from 0.01 to 1 s−1. The tensile temperature has a great influence on the peak flow stress of the bimetal composite. The main microstructure evolution mechanisms, including dynamic recovery (DRV) and dynamic recrystallization (DRX), changed with the deformation temperatures. The different strain rates and the change of strain rates during the deformation process have an influence on the flow behavior of the bimetal composite. During the hot bending process, qualified parts could be formed successfully without obvious cracks in the interfacial zone. Phase and grain orientation spread (GOS) maps of specimens after hot tensile and forming tests were obtained by the electron backscatter diffraction (EBSD) technique to study the microstructure evolution, respectively. It is found that the effect of the working temperature on microstructure evolution is larger than that of the stacking sequence for 2205/AH36 BC. The considerable geometrically necessary dislocation (GND) accumulation occurs around the interface of 2205/AH36 BC under all imposed working conditions after the hot bending process, due to the interfacial micro-defects and complex stress states.
Publisher: Trans Tech Publications, Ltd.
Date: 06-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.76-78.554
Abstract: There are many defects on the surface of continuous casting slab, such as corner cracks, longitudinal cracks etc. To analyze the cracks and determine their locations, two-dimensional heat transfer mathematical model and thermal elasto-plastic stress model of slab casting were established in this paper. The process of solidification, temperature field, and thermal stress distribution on slab surface were analyzed using finite element method. The effect of thermal stress on the cracks on the slab surface was discussed. The location of the cracks caused by thermal stress can be predicted. This is useful for finding approaches to overcome these defects.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Wiley
Date: 28-06-2020
Publisher: Elsevier BV
Date: 03-2020
Publisher: Wiley
Date: 12-12-2023
Abstract: To investigate the association between the timing and adequacy of antibiotics administered to patients presenting with culture‐positive sepsis and septic shock to the ED and in‐hospital mortality and/or intensive care unit (ICU) admission. Multicentre retrospective cohort study of ED presentations at four metropolitan hospitals in Sydney, Australia between January 2017 and November 2019. Encounters for patients aged ≥16 years meeting specified criteria for sepsis or septic shock with antibiotic administration within the first 6 h of presentation were included. Of 7611 encounters included in the study, 2328 (31%) were culture positive, and 2228 (29%) met the criteria for septic shock. In culture‐positive sepsis encounters, partial or inadequate antibiotic coverage was associated with higher risk of death or ICU admission (adjusted odds ratio [AOR] 1.50, 95% confidence interval [CI] 1.04–2.06 and 1.95, 95% CI 1.28–2.99, respectively). This effect was not significant in septic shock encounters (AOR 1.10, 95% CI 0.64–1.88) with partial coverage and (AOR 1.63, 95% CI 0.81–3.3) inadequate coverage. Time to antibiotics was not significantly associated with the risk of mortality/ICU admission. This inference remained the same when analysis was restricted to cases with adequate antibiotic coverage. In a large multicentre s le of patients with culture‐positive sepsis, inadequacy of antibiotics was associated with higher risk of in‐hospital mortality or ICU admission.
Publisher: AIP
Date: 2010
DOI: 10.1063/1.3457536
Publisher: Trans Tech Publications, Ltd.
Date: 03-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.97-101.81
Abstract: Strip shape control during cold rolling of thin strip is a challenge in rolling practice. In the paper, finite element model of strip shape during cold rolling of thin strip in asymmetrical rolling case was successfully developed, and the strip shape such as the thickness distribution along the strip width have been obtained. The developed finite element model has been verified with the experimental value, which shows they are in good agreement. The obtained results are applicable to control the rolled thin strip shape in practice.
Publisher: Wiley
Date: 07-09-2020
DOI: 10.1002/OCA.2670
Publisher: Springer Science and Business Media LLC
Date: 05-2019
Publisher: Elsevier BV
Date: 09-2010
Publisher: Wiley
Date: 03-05-2021
Abstract: To obtain a compatible material with good wear resistance (WR) and toughness, a composite material with high‐chromium cast iron (HCCI) dispersed in low‐carbon steel (LCS) is prepared through multilayer hot rolling. The microstructure and mechanical properties of the composite are investigated. The macrostructure of the composite material reveals that the HCCI layers are necked, fractured, and dispersed in LCS after hot rolling. The two materials combine well without unconnected areas and macrovoids on the interface however, broken oxides are observed at the interface. Decarburization occurs at the LCS side near the interface and a 15−20 μm‐wide ferrite zone is formed at the LCS side. Fe, Cr, Mn, and C elements diffuse at the interface. A pearlite band is formed at the interface, and the thickness of the diffusion is about 2−4 μm. Due to the addition of ductile LCS, the impact toughness of the composite material is about 2.5 times higher than that of the as‐cast HCCI, whereas the WR of the composite material is lower than that of HCCI (about 16%). The dispersed HCCI in the composite produces a shadow effect during the sliding wear, which provides protection and support for LCS.
Publisher: Springer Science and Business Media LLC
Date: 29-04-2014
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2022
Publisher: Trans Tech Publications, Ltd.
Date: 02-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.887-888.1115
Abstract: Titanium and its alloys have excellent properties and are promising biomaterial in medical engineering field. A bioactive surface on a Ti substrate is a prerequisite for great performance and long service life of implants. Based on the mechanism for inducing cell/tissue responses, three kinds of methods, namely morphological, physicochemical and biochemical methods, are reviewed in this paper. Hybrid methods that integrate in idual methods or have additional functions are also discussed.
Publisher: Bentham Science Publishers Ltd.
Date: 29-04-2011
Publisher: Elsevier BV
Date: 07-2018
DOI: 10.1016/J.JCIS.2018.03.015
Abstract: Processing conditions deeply affect the mechanical, chemical and biological properties of elastomeric based nanocomposites. In this work, multi-walled carbon nanotubes (MWCNTs) were dispersed in poly(glycerol sebacate) (PGS) prepolymer, followed by curing under vacuum at 120 °C. It was observed an increase of the water contact angle with the amount of MWCNTs added, as well as the tensile strength and Young modulus, without compromising the elastomeric behaviour of the pristine PGS matrix. The cross-linking degree was determined by the Flory-Rehner swelling method and through the mechanical rubber elasticity model, and an increase of more than six-fold was observed, which demonstrates the chemical conjugation between the MWCNTs and the PGS polymer chains, resulting in stiff and elastomeric nanocomposites. Finally, in vitro cell culture of adult mouse hypothalamus neurons A59 cells showed good support for cell viability and stimulation for axons and dendrites growth. The unique features of these nanocomposites make them promise for biomedical applications, as soft tissue substrates with tailored mechanical properties.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Inderscience Publishers
Date: 2012
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4806864
Publisher: American Scientific Publishers
Date: 30-06-2012
Publisher: Wiley
Date: 04-09-2013
DOI: 10.1111/FFE.12102
Publisher: Elsevier BV
Date: 09-2009
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 03-2020
Publisher: Trans Tech Publications, Ltd.
Date: 06-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.941-944.1876
Abstract: In the last few decades, there is a global interest in micro products, and micro forming of metals is a promising micro manufacturing method. However, a comprehensive understanding of this process is absent. Therefore, this study aims to investigate micro deep drawing process via experimental and analysis work. Simulation results are in good agreement with the experimental data. The comparison between the finite element method (FEM) simulation and experimental results shows the feasibility of FEM simulation for micro deep drawing process. This research also lays a fundament of investigating micro forming process, especially micro deep drawing.
Publisher: SAGE Publications
Date: 03-09-2020
Abstract: This paper puts forward a simplified FEM based on MATLAB PDE tool to investigate the static performance of aerostatic journal bearings. The pressure distribution equation is transformed into a standard elliptic equation, the boundary conditions and coefficients of the transformed equation are also confirmed by contrasting it with the standard elliptic equation. Then the effects of bearings structural parameters and external supply pressure on the film pressure distribution, load capacity and static stiffness are studied. The film pressure distribution changes significantly with the eccentricity ratio, and an eccentricity range corresponding to the optimal stiffness is also confirmed. Finally, an experimental platform with reversal structure is applied to reduce the measurement error, the maximum relative error between the results of simulation and experimental result is 11.54%.
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.443.39
Abstract: A set of new mathematical models have been developed to calculate the temper rolling force of 2050 strip temper rolling mill. Based on the fact of small plastic deformation and elastic deformation occurring on the entry and exit of the deformation zone, new stress boundary conditions are described. The inhomogeneous distribution of internal stress in thickness direction is taken into account in the models, instead of uniform internal stress and assumption of plane strain traditionally. The new mathematical models have been applied into the temper rolling of 2050 hot rolling mills with good results. Comparison of calculated values and testing values for nine typical products has been given. The result shows that the calculated value of rolling force of temper mill is accurate.
Publisher: Springer Science and Business Media LLC
Date: 26-10-2020
Publisher: Springer Science and Business Media LLC
Date: 19-03-2015
Publisher: Elsevier BV
Date: 12-2018
Publisher: Inderscience Publishers
Date: 2012
Publisher: SAGE Publications
Date: 03-2008
Abstract: In this paper, the flattening of the model asperities under large bulk strain has been experimentally and theoretically investigated. The specimens with two types of model asperities (pyramid-shaped asperity and ridge-shaped asperity) on the top surface are compressed by a flat punch. The measured contact ratios are used to validate the theoretical model. The rigid-plastic finite-element method model is developed to analyse the asperity flattening processes under bulk straining. The results show that the contact ratio increases with bulk strain and the contact pressure for both types of asperities. The ridge-shaped asperity exhibits a higher contact ratio than the pyramid-shaped asperity. The contact ratio also increases with the asperity angles in the presence of large bulk deformation.
Publisher: SAGE Publications
Date: 03-06-2018
Abstract: This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive litude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive litude effect can be ignored at the condition of litude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and d ing coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.
Publisher: Iron and Steel Institute of Japan
Date: 2015
Publisher: Elsevier BV
Date: 05-2005
Publisher: Springer Science and Business Media LLC
Date: 11-2019
Publisher: American Scientific Publishers
Date: 08-2011
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Scientific Publishers
Date: 04-2011
Publisher: Springer Science and Business Media LLC
Date: 04-06-2015
Publisher: American Scientific Publishers
Date: 07-2011
Publisher: Springer Science and Business Media LLC
Date: 09-08-2019
Publisher: Elsevier BV
Date: 05-2019
Publisher: Trans Tech Publications, Ltd.
Date: 12-2017
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.725.689
Abstract: Tooling feature size to minimum thickness becomes small in micro scale products and its ratio affects the deformation behavior in micro sheet forming significantly. In this study, the effect of this relative tooling feature size on drawing characteristics and effects to improve the drawability, such as friction holding effect, hydrodynamic lubrication effect and compression effect by blank edge radial pressure, in micro hydromechanical deep drawing (MHDD) are investigated using plasticity theory and numerical simulation. The results show that the micro drawing characteristics in MHDD can be improved by applying counter pressure. However, the required fluid pressures for friction holding and hydrodynamic lubrication effects increase as the relative punch diameter and/or die shoulder radius to thickness decrease, although the compression effect by radial pressure on the blank edge is independent of the relative tooling feature size.
Publisher: Wiley
Date: 27-01-2023
Publisher: MDPI AG
Date: 04-2022
DOI: 10.3390/MA15072600
Abstract: Water-based lubricants with different fractions of TiO2 nanoparticles ranging from 1.0 to 9.0 wt.% were utilized to study the lubrication mechanisms during micro rolling tests and the tribological behaviour of nanolubricants during the micro rolling of copper foils. The results indicate that the application of TiO2 nanolubricants remarkably improves the surface quality of rolled copper foils during rolling processes. For lubricants with inadequate TiO2 nanoparticles, it is found that few TiO2 nanoparticles enter the contact regions between the rolls and foils, causing insufficient lubrication during rolling processes. Instead, for lubricants with excessive TiO2 nanoparticles, obvious agglomeration occurs at the contact regions and promotes the generation of voids on the surface of the rolled foils, thereby deteriorating the surface quality of the rolled copper foils. In addition, it is found that the surface quality of rolled foils is improved by utilizing a large reduction ratio. Overall, the fraction of 3.0 wt.% TiO2 nanolubricants is optimal to improve the lubrication conditions at the contact regions, thereby improving the surface quality of the rolled copper foils.
Publisher: Springer Science and Business Media LLC
Date: 09-07-2014
Publisher: Elsevier BV
Date: 05-2009
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1155/2018/1735046
Abstract: The effects of thickness reduction, feed ratio, and ball diameter, and their coupling effects, on the average relative stress triaxiality during spinning are discussed via simulation results. The relationships among the parameters and the average value of relative stress triaxiality (AVRST) are fitted with multiple nonlinear functions to calculate the optimal process parameters. According to the trend of stress triaxiality, the corresponding process parameters are calculated for the minimum average value of relative stress triaxiality (AVRST). Room temperature experiments performed on an AZ31 magnesium alloy thin-walled tube with the optimal parameters reveal an improvement of cracking of the tube surface. The study reveals changes in the minimum AVRST and aids in selecting the process parameters to improve plastic performance.
Publisher: Elsevier BV
Date: 07-2006
Publisher: Elsevier BV
Date: 07-2006
Publisher: Trans Tech Publications, Ltd.
Date: 02-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.189-193.3001
Abstract: In recent years, the number of automobiles has been steadily increasing, which has significantly impacted on the society and human life, and led to many social problems such as fuel crisis, environment pollution. Therefore, lightweight designing becomes a focused issue. Lightweight materials application, optimized structure design and advanced manufacturing process are the main ways to achieve the lightweight. However, low plasticity and ductility of high strength steel constrain the application of high strength steel. In this paper, the basic principle of roll forming for automotive parts is investigated, and it is innovatively applied in the hot roll forming process of the ultra high strength steel.
Publisher: Elsevier BV
Date: 09-2004
Publisher: Trans Tech Publications, Ltd.
Date: 10-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.145.287
Abstract: In twin-roll thin strip casting, the temperature distribution of casting roll affects the roll thermal stress, and influences the thermal deformation, the generation of roll surface cracks, the strip shape, and the service life of casting roll. In this paper, the temperature distributions of casting roll have been analysed, the effects of the roll sleeve thickness on the temperature field and thermal stress of casting roll have been simulated and discussed. The developed temperature model of casting roll is helpful in optimising the processing parameters and the design of casting roll during twin-roll thin strip casting.
Publisher: Trans Tech Publications, Ltd.
Date: 10-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.146-147.1642
Abstract: Based on the cooling parameters of the mold copper plate for slab continuous casting in a steelmaking plant, the three-dimensional calculating model of the copper plate was established, and three-dimensional distributions of temperature, thermal stress and strain were simulated numerically by using finite element method (FEM). The maximum deformation of the mold copper plate, the highest temperature and thermal stress were obtained. This research is useful for the structure design of the mold.
Publisher: Elsevier BV
Date: 09-2004
Publisher: Elsevier BV
Date: 05-2013
Publisher: Springer Science and Business Media LLC
Date: 03-07-2018
Publisher: Springer Science and Business Media LLC
Date: 09-2012
Publisher: Wiley
Date: 23-09-2021
Abstract: In the tandem cold rolling (TCR) process, the work hardening effect has a direct influence on the rolling force, which affects the strip shape, including the strip crown and flatness, significantly. However, previous studies focus on the single finite element (FE) model, ignoring the work hardening effect. To investigate the effect of the rolling force on strip shape, herein, a novel elastic–plastic multistand FE model for the TCR process with consideration of the work hardening effect is proposed for the first time using a segmentation modeling strategy, data transfer technologies, and element remesh technology. The proposed FE model is verified by comparing with industrial experimental results. The effects of rolling force on the strip crown and flatness at each stand are investigated quantitatively using the developed FE model. The results illustrate that the strip crown at 40 mm from the edge ( C 40 ) is in a decreasing trend when the rolling force decreases from stand 1 (S1) to stand 4 (S4). By contrast, interestingly, two opposite trends of C 40 are found at stand 5 (S5). This work provides a fresh perspective on the TCR simulation and contributes to further understanding the effect of the rolling force on the strip shape.
Publisher: EDP Sciences
Date: 2018
DOI: 10.1051/MATECCONF/201818500012
Abstract: Bimetal composites have wide applications due to their excellent overall performance and relatively low comprehensive cost. The aim of this study is to investigate the forming behaviour of stainless/carbon steel bimetal composite during st ing by finite element method (FEM). In this work, the bonding interface of bimetal composite sheet was assumed to be perfect without delamination during the plastic forming process for simplicity. Uniaxial tensile tests on base metal (carbon steel) and compositing metal (stainless steel) were first carried out, respectively, in order to obtain the tensile properties of each of the component materials required in the forming simulation. Processing variables, including the layer stacking sequence, relative thickness ratios of two layers and friction were considered, and their effects on the distributions of circumferential stress and thickness strain were analysed. The bimetal composite sheet was set as the eight-node solid elements in the developed FEM model, which is effective for evaluating the distributions of circumferential stress and thickness strain, and predicting the high-risk region of necking during the st ing of bimetal composites. The simulation results can be used as an evaluation indicator of the capability of forming machine to ensure the bimetal composite can be safely formed.
Publisher: Springer Science and Business Media LLC
Date: 29-08-2016
Publisher: Trans Tech Publications, Ltd.
Date: 05-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.923.8
Abstract: Graphene has been proved to be an excellent enhancer in metal matrix composites. Core-shell structured SiC nanoparticles and graphene nanosheets (GNSs) were fabricated and incorporated into aluminum matrix using ball milling in the current study. Graphite powder was exfoliated into thin GNSs, which are flexible to wrap SiC nanoparticles. The ductile aluminum particles were firstly flattened and then repeatedly welded and fractured into equalized particles during the ball milling of Al alloy-SiC-GNSs composite powder, which were observed using scanning electron microscopy and X-Ray diffraction. SiC-GNSs were embedded and dispersed into the aluminum matrix during the milling process.
Publisher: Trans Tech Publications, Ltd.
Date: 12-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.418-420.1158
Abstract: The mathematic model of CVC-Plus work roll curve is built. The ratio of the initial shifting value to the target crown is determined, and the mathematical model considering the relationship between the coefficients A 2 , A 3 , A 4 , A 5 and is established. According to the theoretical analysis, the distance between the maximum or minimum point of the high order equivalent crown for work roll with CVC-plus roll curve and the rolling central point is the times of the roll barrel length. In general, the initial shifting value of the CVC-plus roll curve is not equal to the initial shifting value of the 3-order CVC roll curve . The coefficient A1 can also be obtained by optimizing the target function with minimizing the axial force.
Publisher: Springer Science and Business Media LLC
Date: 09-11-2015
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4806832
Publisher: Wiley
Date: 13-05-2018
Abstract: The arterial to end-tidal carbon dioxide tension difference (CO Patients presenting to tertiary Australian ED with suspected sepsis (n = 215) underwent near-simultaneous end-tidal carbon dioxide and partial pressure of carbon dioxide measurements. We investigated the correlation of CO Among patients included in the analysis (n = 165), the CO In this pilot study of patients with suspected sepsis from non-respiratory causes, an increased CO
Publisher: Elsevier BV
Date: 11-2015
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.633-634.63
Abstract: Cu-14Fe and Cu-17Fe alloys were produced by casting and processed into in situ composites by hot and cold deformation, and intermediate heat treatment. The microstructures were investigated by using a scanning electron microscope and an optical microscope. The electrical conductivity was evaluated by using a digital micro-ohmmeter. The tensile strength was measured by using an electronic tensile-testing machine. The results show that there are similar cast and deformation microstructures in Cu-14Fe and Cu-17Fe. The tensile strength of deformation-processed Cu-17Fe in situ composite is much higher than that of Cu-14Fe, while the conductivity of deformation-processed Cu-17Fe in situ composite is slightly lower than that of Cu-14Fe at the same cold deformation strain. The Cu-17Fe in situ composite produced by using proper thermo-mechanical processing possesses a good combination of tensile strength and electrical conductivity.
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 07-2022
Publisher: Elsevier BV
Date: 05-2018
Publisher: Springer Science and Business Media LLC
Date: 20-01-2022
Publisher: Elsevier BV
Date: 04-2019
Publisher: Springer Science and Business Media LLC
Date: 25-08-2015
Publisher: IGI Global
Date: 2011
DOI: 10.4018/IJMMME.2011010103
Abstract: The oxidation of stainless steels 304 and 304L during hot rolling is studied in this paper. Results show the oxide scale thickness decreases significantly with an increase of reduction, and the oxide scales of both 304 and 304L stainless steels were found more deformable than the steel substrate. Surface roughness shows a complicated transfer during the hot rolling process due to the complexity of oxide scale characteristics. Also, surface roughness decreases with an increase of reduction. The friction coefficient increases with reduction in all cases, and the increase is more significant in the case of the 304 stainless steel than that of 304L stainless steel.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Springer Science and Business Media LLC
Date: 13-02-2018
Publisher: SAGE Publications
Date: 10-2019
Abstract: Wrinkling is one of the main failure modes in sheet metal forming process and may lead to assembly problems of the parts. Control of wrinkling is difficult due to the complex deformation behavior of the sheet metal. A finite element model for side blankholder method to control wrinkling was established and used for the simulation. Trials and simulations were conducted to analyze the parameters of wrinkling characteristics. Results show that with the increase in the angle of the side blankholder, the resistance force of the side blankholder decreases. The blank length on the side blankholder should be small enough. The fillet radius of the side blankholder should be large enough to reduce the deformation. The bottom gap between the die and the side blankholder cannot be too large because the support of the blank will decrease in the forming process. In order to verify the simulation results, three blank lengths (20, 15, and 5 mm) over the side blankholder were used in the experiment. The results of the comparison tests testify the reliability of the simulation. The optimal parameter of the blank length is 5 mm. A new cl method was designed for wrinkling control to overcome the shortcomings of the side blankholder method. The precision of the part met the requirement using soft rubber and two layers of rubber plates.
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.66
Abstract: Microforming technology has attracted more and more attention because of its high utilization in almost every field. However, due to size effect, the conventional scale mechanical processing theories could not be applicable. Further, the characteristic of each single grain involved in the deformed area activates to play a significant role in the manufacturing process. In order to reflect and investigate the relationship among these grains better, this paper represents a pre-process modeling method with Voronoi tessellation to reveal the grained heterogeneity of workpiece numerically in order to obtain high accuracy and prediction result in finite element (FE) modelling of microforming process. Corresponding micro V-bending experiments have been carried out, and the experimental results are in good agreement with simulation results in terms of final angles after micro bending with consideration of springback.
Publisher: Wiley
Date: 23-03-2018
Abstract: Pain management and patient satisfaction are key markers for health systems performance. There is a lack of consensus on the role of analgesia, its adequacy, and its links to patient satisfaction in the ED. The present study aimed to assess the relationship between adequacy of analgesia and patient satisfaction in the ED setting. Consenting adult patients (n = 115) presenting to the ED with pain were enrolled, and their pain tracked throughout admission with 11 point numerical pain scores. Eleven point numerical scores were also utilised to measure satisfaction and compassion at the end of each ED stay. The primary outcome was patient satisfaction score ≥7. Of 115 enrolled patients, 94 (81.7%) were eligible for analysis. Median time to physician evaluation was 54.0 min (inter-quartile range [IQR] 35.0-98.0) and median ED length of stay was 205 min (IQR 129.0-280.0). Fifty-four patients (57.5%) received analgesia during their stay, of whom 36 (38.3%) had a significant response to analgesia (≥2 change in pain score). Median time to analgesia was 87.5 min (IQR 66.1-108.9). Patient satisfaction was inversely associated with male sex, and positively correlated (Spearman's rank correlation P < 0.05) with increasing age, significant change in pain score (±2) and compassion scores. In the present study of patients presenting to the ED with pain, oligoanalgesia remains a significant issue. Male sex was inversely associated with satisfaction, whereas compassion, and significant change in pain score were associated with improved patient satisfaction. Of the factors analysed, staff compassion demonstrated the strongest correlation with satisfaction.
Publisher: Springer Science and Business Media LLC
Date: 15-05-2020
Publisher: Elsevier BV
Date: 10-2016
Publisher: Trans Tech Publications, Ltd.
Date: 10-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.874.381
Abstract: Oxide scale formed on the steel surface during hot rolling affects the tribological property of nanoTiO 2 additive oil-in-water (O/W) lubricant, resulting in changes of roll forces, torques and power consumption, as well as the wear and the surface quality of the work roll and workpiece in hot rolling. The nanoparticle additive O/W emulsion is a novel lubricant and has a great potential to be used in hot rolling process. However, little research has focused on the nanoparticle additive O/W emulsion. In this study, oxidation, tribological and hot rolling tests were conducted to investigate the tribological behaviour of nanoTiO 2 additive O/W lubricant. The results indicate that the surface morphology of the oxide scale plays an important role in tribological behaviour of nanoTiO 2 additive O/W lubricants. The coefficient of friction (COF) and rolling force are reduced with the addition of nanoTiO 2 particles into the 1.0% (mass %, oil concentration) O/W lubricant. This study is helpful in applying the nanoTiO 2 additive O/W lubricant during hot rolling to realise reduction of rolling force and power consumption.
Publisher: IOP Publishing
Date: 24-02-2021
Abstract: The brittle–ductile transition (BDT) widely exists in the manufacturing with extremely small deformation scale, thermally assisted machining, and high-speed machining. This paper reviews the BDT in extreme manufacturing. The factors affecting the BDT in extreme manufacturing are analyzed, including the deformation scale and deformation temperature induced brittle-to-ductile transition, and the reverse transition induced by grain size and strain rate. A discussion is arranged to explore the mechanisms of BDT and how to improve the machinability based on the BDT. It is proposed that the mutual transition between brittleness and ductility results from the competition between the occurrence of plastic deformation and the propagation of cracks. The brittleness or ductility of machined material should benefit a specific manufacturing process, which can be regulated by the deformation scale, deformation temperature and machining speed.
Publisher: Springer Science and Business Media LLC
Date: 29-12-2015
Publisher: Elsevier BV
Date: 07-2019
Publisher: EDP Sciences
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 25-11-2009
Publisher: Elsevier BV
Date: 05-2000
Publisher: MDPI AG
Date: 18-02-2021
DOI: 10.3390/MET11020341
Abstract: In this study, WC-Ni/high-speed steel composite materials for application as micro-drills were prepared by cold pressing and high-temperature vacuum sintering using a self-designed mold in the laboratory. The effect of Ni on the microstructure and diffusion behavior at the interface of the WC/high-speed steel composite was investigated. The results show that the addition of Ni promoted the diffusion of elements, and reduced defects such as micropores and microcracks at the WC/high-speed steel composite interface. It also improved the bonding strength of the WC/high-speed steel composite interface, and significantly decreased the WC hardness.
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.71
Abstract: The compressive strain hardening behaviour of a novel bimetal with pearlitic steel and low carbon steel was investigated by computational analysis based on the isothermal compression tests in a wide range of deformation temperature and strain rate. The Hollomon’s equation was employed to calculate the strain hardening exponent (SHE) with the assistance of mathematical manipulation. The result shows that the logarithmic relationship between the flow stress and plastic strain of the bimetal is highly non-linear, which results in the variation of the SHE of the bimetal. This variation reflects the dynamic competition between the strain hardening and softening mechanism by the varying value of the SHE in the range of 0.4 to-0.4. Furthermore, the influences of deformation temperature and strain rate on the SHE are significant. With decreasing temperature and increasing strain rate, the strain hardening of the bimetal was enhanced, while the dynamic recrystallisation was activated under the opposite conditions with the evidence of negative SHE value.
Publisher: Wiley
Date: 2000
DOI: 10.1002/1099-0887(200009)16:9<601::AID-CNM358>3.0.CO;2-6
Publisher: Trans Tech Publications, Ltd.
Date: 2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.275-277.2214
Abstract: The behaviour of the surface defects on the continuous casting slab during hot rolling is investigated using the commercial FE-code LS-DYNA. The thermo-elastic-plastic material model is chosen in the simulation models, and the material implemented in the simulation is the austenitic stainless steel 304. The numerical results show the significant morphological changes of the surface defects during hot rolling and afford valuable indications for a deeper understanding of the underlying process. An accelerated crack growth and propagation are observed for the edge cracks, and the closure behaviour is found in the transverse and longitudinal cracks. The effect of temperature is significant on both the roll and the strip in hot rolling process. The developed models consider different types of mesh and element, thermal conditions, and rolling schedules. The predicted relationship between rolling conditions, the temperature distribution of crack, and the full history of temperature variation are discussed in this study.
Publisher: Elsevier BV
Date: 06-2007
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 09-2003
Publisher: Trans Tech Publications, Ltd.
Date: 09-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.797.725
Abstract: This investigation attempts to improve the wear resistance of low chromium white cast iron (LCCI) by thermomechanical treatment. The thermomechanical treatment of the brittle LCCI with crack-free was successfully carried out by bonding it with a ductile low carbon steel firstly. Afterwards the dry sliding wear behavior of as-cast (LCCI-A) and thermomechanically processed (LCCI-B) s les was studied using a pin-on-disc apparatus under different test conditions. The microstructural examination shows that the refined supercooled austenite and plenty of secondary carbides in LCCI-B replaced the original microstructure of martensite and retained austenite with network carbide in LCCI-A. This significant evolution is beneficial to form and stabilise the oxide layer on the substrate, which makes the oxidational wear rather than abrasive wear or delamination dominating the wear process so that the improvement of the wear resistance of LCCI was achieved by hot working.
Publisher: Elsevier BV
Date: 09-2015
Publisher: SAGE Publications
Date: 25-03-2018
Abstract: In this paper, the pressure distribution of aerostatic thrust bearings with vacuum pre-loading was investigated by solving the full Navier–Stokes equations based on the computational fluid dynamics method. The influences of the supply pressure, vacuum pressure, orifice diameter, and gas film thickness on the absolute pressure ratio were investigated. The finite difference method was used to study the effects of the vacuum chamber area, orifice diameter, orifice number, supply pressure, and vacuum pressure on the bearing stiffness. It is confirmed that the orifice diameter and film thickness had a great influence on the absolute pressure ratio, which increased with the reduction in the gas film thickness and the rise in the orifice diameter. The bearing stiffness can be improved by increasing the supply pressure, orifice number or vacuum chamber area or decreasing the orifice diameter or vacuum pressure, which provides useful guidance for the optimization design of aerostatic thrust bearings with vacuum preloading.
Publisher: Springer Science and Business Media LLC
Date: 22-03-2022
Publisher: Annals of Laboratory Medicine
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 29-11-2012
Publisher: Elsevier BV
Date: 04-2013
Publisher: Chinese Journal of Mechanical Engineering
Date: 2012
Publisher: Trans Tech Publications, Ltd.
Date: 08-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.626.397
Abstract: A micro hydromechanical deep drawing is carried out using the pure titanium and the effect of fluid pressure on formability of pure titanium is investigated. The experiments are performed using the two kinds of pure titanium foils (TR270C-H and TR270C-O) and stainless steel foil (SUS304-H) with 50 thickness and the cylindrical and conical punches. As a result, it is found that the peeling off the oxide film of pure titanium can be reduced by applying the fluid pressure because the friction force and contact pressure between the blank and die decreases. However, the formability is lower for pure titanium than that for stainless steel because the tensile strength is low and the friction force is easy to increase as the friction force increases. In contrast, due to the low young modulus of pure titanium, the restriction of wrinkling, decrease of friction force and friction holding effect can be obtained at low fluid pressure.
Publisher: Elsevier BV
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 17-09-2016
Publisher: Trans Tech Publications, Ltd.
Date: 09-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.797.713
Abstract: As limited results were reported in terms of the evolution of sliding friction with growth of oxide layer in thickness during running-in, a pin-on-disc wear test was carried out in this study. 4.8Ni-1.5Cr cast iron as core layer and low carbon steel as outer layers, were thermo-mechanically processed via three different routes. For s les with lower hardness due to their predominantly austenitic or martensite retarded matrices, we found that initially rapid increase of thickness of oxide layer continually lowers the sliding friction. However, after the oxide layer was beyond a certain thickness, the sliding friction began to increase consecutively. After a fluctuation of friction caused by the break-down of oxide, a mild equilibrium wear with roughly constant friction followed.
Publisher: Wiley
Date: 16-01-2018
Abstract: Sepsis is characterised by organ dysfunction resulting from infection, with no reliable single objective test and current diagnosis based on clinical features and results of investigations. In the ED, investigations may be conducted to diagnose infection as the cause of the presenting illness, identify the source, distinguish sepsis from uncomplicated infection (i.e. without organ dysfunction) and/ or risk stratification. Appropriate s le collection for microbiological testing remains key for subsequent confirmation of diagnosis and rationalisation of antimicrobials. Routine laboratory investigations such as creatinine, bilirubin, platelet count and lactate are now critical elements in the diagnosis of sepsis and septic shock. With no biomarker sufficiently validated to rule out bacterial infection in the ED, there remains substantial interest in biomarkers representing various pathogenic pathways. New technologies for screening multiple genes and proteins are identifying unique network 'signatures' of clinical interest. Other future directions include rapid detection of bacterial DNA in blood, genes for antibiotic resistance and EMR-based computational biomarkers that collate multiple information sources. Reliable, cost-effective tests, validated in the ED to promptly and accurately identify sepsis, and to guide initial antibiotic choices, are important goals of current research efforts.
Publisher: American Society of Civil Engineers (ASCE)
Date: 04-2020
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 12-2000
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 11-2018
Publisher: Trans Tech Publications, Ltd.
Date: 09-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.787.454
Abstract: A three-dimensional dynamic simulation model of the molten iron flow field was presented in the paper with Fluent simulation software. Different operating parameters combinations, including different oxygen lance locations, oxygen pressures and oxygen flows, different arrangements of bottom blowing holes, hole sizes, nitrogen pressures and nitrogen flows were studied. It is shown that the relative optimum value of the distance from top-blow gun to the molten iron surface is 1500 mm, and bottom blowing hole diameter is 20mm, there is no significant difference of the blowing effects found when comparing single ring arrangement with double rings arrangement of 8 bottom blowing holes with only bottom-blow, and the bottom-blow of inner ring is disturbed by top-blow when top and bottom combined blow. Optimized design results have been applied to the design and manufacture of the actual converter, the converter has been successfully used in plant. The actual production results indicate that the desiliconization precision can reach 0.05%, the content of Cr 2 O 3 in the slag after reduction can be less than 2%, better than the technical requirements of 3%, and improve the recovery rate of the chromium. Compared with traditional desiliconization method by iron gutter and iron ladle, desiliconization by converter does not use compression residue agents and reduce the amount of desiliconization agents and slag, and improve the desiliconization efficiency and productivity.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 05-2008
Publisher: Hindawi Limited
Date: 09-01-2017
DOI: 10.1155/2017/6489769
Abstract: The optimization of rolling parameters in order to achieve better strip shape and to reduce rolling force is a challenge in rolling practice. In this paper, thin strip asymmetrical rolling of aluminum at various speed ratios under lubricated condition has been investigated at various combinations of work rolls cross (WRC) angles and work rolls shifting (WRS) values. The effects of strip width, reduction, and rolling speed on strip shape taking WRC and WRS into consideration are discussed. Results show that strip profile improves significantly when the WRC angle is increased from 0° to 1°, with an associated reduction in rolling force. Increasing WRS value from 0 to 8 mm improves the strip profile as well but not as significantly as when WRC angle is increased. No significant improvement was found in strip shape when the strip width was increased. At higher reduction, the strip shape was improved a decrease in the rolling force was also observed. A higher speed ratio was found to be effective only at a higher WRC angle. The effect of lubrication on the strip profile was significant. Results indicate that an optimum combination of WRC, WRS, reduction, width, and speed ratio under lubricated conditions can ensure an improved exit strip profile, reduce rolling force, and obtain a better quality strip.
Publisher: MDPI AG
Date: 09-02-2020
DOI: 10.3390/MA13030791
Abstract: With the introduction of O2 during oil and gas production, the erosion-corrosion rate of tubing steels increases the objective of this report is to explore the reason for this. Erosion–corrosion experiments were performed in environments of CO2 and CO2–O2, respectively. Macrographs, microstructures, and the compositions of erosion-corrosion scales were investigated using a digital camera, scanning electron microscope (SEM), Kevex-SuperDry energy spectrometer (EDS) and X-ray diffraction (XRD). The results show that the erosion-corrosion products are composed of large FeCO3 particles and some amorphous product in the CO2 environment, while they are made up of FeCO3, Fe2O3, Fe3O4, and bits of amorphous product in the CO2–O2 environment. The interface between erosion-corrosion scales and the substrate of 3Cr steel is smooth, and Cr enrichment obviously exists in the erosion-corrosion products in the CO2 condition. However, the erosion-corrosion scale is loose and porous with little Cr enrichment in the CO2–O2 environment, which makes the protectiveness of the erosion–corrosion scale weak, and pitting corrosion occurs. The addition of O2 may destroy the protective FeCO3 scale and Cr enrichment in the erosion-corrosion scale, which may be the main reason for the decline in the level of protectiveness of the erosion-corrosion scale, making it weak in terms of preventing the corrosive medium from diffusing to the substrate.
Publisher: Springer Science and Business Media LLC
Date: 16-11-2015
Publisher: Trans Tech Publications, Ltd.
Date: 06-0660
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.76-78.713
Abstract: A new coupling numerical algorithm has been developed to integrate Finite Difference Method (FDM) with Boundary Element Method (BEM) to analyze shear performance of oil film by iteratively solving a series of equations such as the film flow velocity and shear stress equations for contact bodies in bearing system. With consideration of the variations of viscosity and density with pressure and temperature, the effects of shear stress of oil film layers on lubrication performance of contact surfaces under different loadcases were discussed. Moreover, Germany-made Anton Paar MRD (Magnetic Rheologic Device) was used to determine the relationship between the viscosity and shear stress of lubricating oil. The conclusions were verified to be beneficial to the further study on lubricating performance of heavy contact components and to prolong their service lives.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 06-2007
Publisher: Informa UK Limited
Date: 10-08-2016
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 05-2015
Publisher: EDP Sciences
Date: 2016
Publisher: Elsevier BV
Date: 12-2014
Publisher: Springer Science and Business Media LLC
Date: 05-2018
Publisher: Elsevier BV
Date: 12-2017
Publisher: Wiley
Date: 06-01-2004
Publisher: Trans Tech Publications, Ltd.
Date: 06-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.76-78.544
Abstract: Surface roughness plays an important role in determining the tribological behaviour of mechanical components (e.g. gears and roller bearings etc.) under full-film and mixed (or partial) elastohydrodynamic lubrication conditions. This paper describes a detailed mechanics analysis of the surface roughness transformation of thin strip which has been cold rolled on an experimental mill. Low carbon steel strips were rolled at various speeds and reductions, and the effects of rolling parameters on surface roughness are studied. The results of surface roughness can provide important information to optimise the rolling schedule and to improve the rolled strip quality.
Publisher: EDP Sciences
Date: 2016
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 02-2017
Publisher: Trans Tech Publications, Ltd.
Date: 06-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.76-78.548
Abstract: During the cold rolling of thin strip on the 1220mm five-stand tandem cold mills, scratch marks occur on the surfaces of strip and work roll. The surface quality of strip is degraded and the roll wear increases, which resulting in significant economic loss. In this paper, the mechanics of strip scratch marks was studied by carrying out both field experiments and theoretical analysis. Slippage Factor (SF) and Scratch Mark Factor (SMF) were presented to indicate the conditions of strip scratch marks. Meanwhile, mathematical models and simulation code were developed to optimise the rolling schedules and to improve the scratch marks. The practical application of the developed models to the 1220 mm five-stand tandem cold mills verifies the effectiveness of the developed models. The mathematical models can be applied to other similar tandem cold mills.
Publisher: Springer Science and Business Media LLC
Date: 2016
Publisher: World Scientific Pub Co Pte Lt
Date: 23-04-2015
DOI: 10.1142/S0217979215400329
Abstract: In order to analyze the effects of cold rolling parameters such as the crossing angle and axial shifting value of work rolls on the strip profile, extensive tests were carried out on a 4-high rolling mill equipped with a work roll crossing and shifting system. The results show that the strip profile is nearly flat under asymmetrical rolling. The rolling force was also analyzed in detail by changing the crossing angle and axial shifting value of work rolls.
Publisher: Elsevier BV
Date: 07-2006
Publisher: Elsevier BV
Date: 07-2006
Publisher: Chinese Journal of Mechanical Engineering
Date: 2018
Publisher: Elsevier BV
Date: 07-2020
Publisher: EDP Sciences
Date: 2015
Publisher: Elsevier BV
Date: 08-2018
Publisher: Trans Tech Publications, Ltd.
Date: 07-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.988.257
Abstract: A 3D elastic-plastic finite element method (FEM) model of cold strip rolling for 6-high continuous variable crown (CVC) rolling mill was developed. The rolling force distributions were obtained by the internal iteration processes. The calculated error has been significantly reduced by the developed model. the absolute error between the simulated results and the actual values is obtained to be less than 10μm, and relative error is less than 1%. The developed model is significant in investigating the profile control capability of the CVC cold rolling mill in terms of work roll bending, intermediate roll bending and intermediate roll shifting.
Publisher: Springer Science and Business Media LLC
Date: 08-02-2018
Publisher: Elsevier BV
Date: 04-2019
Publisher: Trans Tech Publications, Ltd.
Date: 15-11-2017
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.879.849
Abstract: Optimisation of the physical and mechanical properties of cold rolled thin strips is achieved by controlling the rolling parameters. In this paper, the factors affecting the low carbon steel thin strip profile of asymmetrical cold rolling have been studied at a speed ratio of 1.3 without lubricant applied. The effect of rolling parameters on the resulting microstructure was also investigated. It was found that under dry condition, work roll shifting and work roll cross angle can improve the strip profile, and the improvement is more significant with an increase of work roll cross angle rather than that of work roll shifting. A slight change in microstructure was evident with increasing work roll shifting values. In addition, effects of rolling parameters on the strip profile and microstructure have also been discussed.
Publisher: Trans Tech Publications, Ltd.
Date: 06-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.76-78.538
Abstract: With the technology advancement, crystal plasticity finite element modeling becomes more and more popular in the simulation of metal forming process. In order to obtain a better understanding of the difference between the Taylor model and finite element model during the simulation of metal forming process, an implicit time-integration procedure with the two polycrystal models is applied in the commercial finite element code ABAQUS to simulate the plane strain compression separately. FCC metal is used in this study. The simulation shows that the two polycrystal models both can predict the compression process approximately. The two modelling results of surface roughness show an agreement with that of the experimental results. However, the side profile calculated by the Taylor polycrystal model is much steeper and straighter than that of finite element polycrystal model. The experimental surface roughness curve shows a high frequency fluctuation. It is much steeper than those of the two models. The simulation results also show that the von Mises stress from the Taylor model is much higher than that of the finite element model.
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 07-1998
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 08-2010
Publisher: Wiley
Date: 10-09-2015
Publisher: Springer Science and Business Media LLC
Date: 2020
Publisher: Springer Science and Business Media LLC
Date: 07-03-2022
DOI: 10.1007/S00170-022-08997-5
Abstract: The strip shape inheritance model is widely applied to improve the strip shape quality in tandem cold rolling (TCR). However, the inheritance mechanism is still currently unclear. To bridge this gap, this paper presents a new numerical method for calculating the strip crown inheritance factor. In addition, the effects of the entry strip crown on exit strip crown and flatness were quantitatively analysed at each stand in the TCR using a novel three-dimensional (3D) multi-stand elastic–plastic finite element (FE) model. The results show that the strip crown inheritance factor increases slowly from S1 (stand 1) to S3 (stand 3), while rising sharply from S3 to S5 (stand 5), reaching a peak value of 0.495 μm/μm at S5. This trend coincides with that of strip plastic rigidity, which verifies that the strip crown inheritance factor is dependent on the strip plastic rigidity. Furthermore, the variation of strip crown and flatness under different entry strip crowns from S1 to S5 is jointly influenced by the pass reduction and strip plastic rigidity. Moreover, the strip crown inheritance factor increases with the deformation resistance of the strip at both S1 and S5. These findings not only offer a fresh perspective to understand the mechanism of strip crown inheritance, but also provide an important basis for optimising the strip shape control in the TCR process.
Publisher: Elsevier BV
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 18-10-2019
Publisher: Elsevier BV
Date: 2016
Publisher: Informa UK Limited
Date: 08-09-2021
Publisher: Elsevier BV
Date: 11-2014
Publisher: Springer Science and Business Media LLC
Date: 15-07-2014
Publisher: Trans Tech Publications, Ltd.
Date: 12-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.422.268
Abstract: The design of a Fuzzy-PID controller involves setting the fuzzy rules, membership functions and its associated scaling factors. How to obtain a better control result and how these scaling factors affect the controller’s performance are still a challenge. In this paper, the automatic position control system of a Hille 100 experimental rolling mill was used as a research testbed. Based on the mathematical control model of the rolling mill, a Fuzzy-PID controller was developed, and the process of implementing global optimization considering all these factors simultaneously by using genetic algorithm is introduced in detail. Through simulation, the performance of the control system with multifactor optimized Fuzzy-PID controller is given, and compared with that with only the fuzzy rules optimized in the controller. By simulation tests, it is found that these factors will influence the control performance of the controller, and that they are highly coupled with each other. The more factors for a Fuzzy-PID controller are optimized, the better the solution will be. It can also be inferred from the study that asymmetrical membership functions have more potential in improving a fuzzy controller’s performance than symmetrical ones. The multifactor optimization method presented in this paper can in principle also be used to solve other complicated optimization issues.
Publisher: Elsevier BV
Date: 07-2006
Publisher: Elsevier BV
Date: 05-2001
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 12-2002
Publisher: Wiley
Date: 02-08-2017
Abstract: Age-related policies allow adolescents to access paediatric and adult EDs. Anecdotally, paediatric and adult EDs report challenges when caring for older and younger adolescents, respectively. Our aim was to describe the characteristics of an adolescent population attending an adult ED, co-located with a tertiary paediatric ED. The Westmead Hospital ED database was accessed for 14.5-17.9 years old presentations between January 2010 and December 2012. Patient diagnosis coding (SNOMED) was converted to ICD-10. De-identified data were transferred into Microsoft Excel with analysis performed using spss V22. There were 5718 presentations made to the Westmead Hospital, Sydney, Australia ED by 4450 patients, representing 3.3% (95% CI 3.2-3.4) of total visits from all patients 14.5 years and above. The mean age of the s le was 16.6 years (male 51.8%). Presentations triaged as level 4 or 5 represented 61.0% (95% CI 58.7-61.3) of visits. The proportion of patients who did not wait to receive care was 13.8% (95% CI 12.9-14.7), which was significantly higher than adult rates (P < 0.01). There were 279 unscheduled return visits (visits made <72 h of discharge) representing 4.9% (95% CI 4.4-5.8) of all presentations. Injury was the most common diagnosis (30.2%, 95% CI 28.8-31.6). Chronic physical illness and alcohol-related visits comprised 2.1% (95% CI 1.7-2.5) and 0.8% (95% CI 0.6-1.0) of adolescent presentations, respectively. Contrary to reported staff perceptions, adolescent chronic physical illness presentations were not a major burden. Alcohol was likely under-recorded as a contributing factor to presentations.
Publisher: Elsevier BV
Date: 04-2016
Publisher: Springer Science and Business Media LLC
Date: 04-2020
Publisher: Elsevier BV
Date: 09-2003
Publisher: Elsevier BV
Date: 08-2008
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 02-2004
Publisher: IOP Publishing
Date: 13-04-2016
No related grants have been discovered for Zhengyi Jiang.