ORCID Profile
0000-0003-0256-8233
Current Organisation
The University of Newcastle
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Mechanical Engineering | Materials Engineering | Numerical Modelling and Mechanical Characterisation | Biomaterials | Biomedical Engineering | Reaction Kinetics And Dynamics | Heat And Mass Transfer Operations | Physical Metallurgy | Composite Materials | Computational Heat Transfer | Energy Generation, Conversion and Storage Engineering | Condensed Matter Modelling and Density Functional Theory | Condensed Matter Characterisation Technique Development | Numerical Analysis
Expanding Knowledge in Engineering | Solar-thermal | Energy storage | Skeletal System and Disorders (incl. Arthritis) | Metals (composites, coatings, bonding, etc.) | Other non-ferrous metals (e.g. copper,zinc) | Solar-Thermal Energy | Energy Storage (excl. Hydrogen) | Cardiovascular System and Diseases | Machined Metal Products | Metal Castings | Child Health |
Publisher: SAGE Publications
Date: 28-07-2017
Abstract: The main purpose of this paper is to present the basic fatigue properties of metal matrix syntactic foams. The investigated syntactic foams consisting of expanded perlite and A356 aluminum matrix were produced using an inert gas pressure infiltration technique. The obtained foams were subjected to cyclic compressive loading in order to investigate their fatigue properties. The standard procedure for cyclic fatigue testing was slightly modified to account for the variation of porosity and strength which is typical for metallic foam s les. This approach allows the direct comparison of the fatigue test results between all investigated s les. Depending on the applied load level, two different failure mechanisms were identified that resulted in characteristic deformation – loading cycle curves. The failure mechanisms were further investigated on the microstructural scale: traces of fatigue beachmarks and extensive plastic deformation were found. Furthermore, Wöhler-like deformation – lifetime diagrams were created in order to predict the expected lifetime of the properties of metal matrix syntactic foams .
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 12-2010
Publisher: MDPI AG
Date: 21-05-2016
DOI: 10.3390/MA9050398
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 06-2016
Publisher: Wiley
Date: 02-2008
Publisher: SAGE Publications
Date: 27-08-2018
Abstract: Perlite–metal syntactic foam is a novel lightweight material with good specific strength and excellent energy absorption capabilities. To analyse its suitability in marine applications, perlite–metal syntactic foam has been immersed for 2 years in natural flowing seawater. The change of mass and mechanical properties has been studied as a function of exposure time. Results indicate a slow degradation of mechanical properties that can be attributed to a change of the macroscopic deformation mechanism. Interestingly, no evidence of significant corrosion was observed. Instead, the change in mechanical properties is triggered by the sedimentation of oxides and sulphates within the expanded perlite particles. Implications towards the long-term viability of such perlite–metal syntactic foam in marine applications are discussed.
Publisher: Elsevier BV
Date: 06-2018
Publisher: SAGE Publications
Date: 20-10-2009
Abstract: This article is on the numerical determination of the mechanical properties of adhesively bonded hollow sphere structures (HSS). Two types of morphologies, namely syntactic and partial HSS, are considered. In the case of syntactic HSS, the hollow steel spheres are completely embedded in adhesive matrix, whereas for partial HSS the adhesive is concentrated at the contact points of neighbouring spheres. In addition to the elastic properties of the structure, the initial tensile and compressive yield strengths and the 1% offset yield strengths are calculated and compared for both configurations. Here, the anisotropic behavior of the adhesive in the tensile and compressive regime is incorporated. It could be shown that both configurations reveal quite different behavior on the macro-scale and therefore can be chosen according to specific requirements. Furthermore, the applicability of the adhesive as design parameter for the mechanical properties of HSS is shown.
Publisher: MDPI AG
Date: 10-11-2020
DOI: 10.3390/MA13225065
Abstract: The number of shark attacks resulting in fatalities and severe injuries has increased steadily over recent years. This is mainly attributed to a growing population participating in ocean sports such as swimming, ing, and surfing. To mitigate the severity of shark attacks, the current study presents a novel fibre-reinforced composite for bite protection. This material is intended for integration into neoprene wetsuits, e.g., in the form of protective pads. A suitable material must be able to withstand significant bite forces, which are concentrated within a small contact area at the tips of the shark teeth. At the same time, the material should not hinder the complex motion sequences of aquatic sports. To this end, a novel fibre-reinforced composite was created by integrating Kevlar fibres into an elastic matrix. Uni-axial testing using shark teeth replicas was conducted on a specially designed test rig to quantify the effectiveness of the novel protective material.
Publisher: Elsevier BV
Date: 2020
Publisher: MDPI AG
Date: 28-02-2020
DOI: 10.3390/MET10030314
Abstract: This paper introduces a novel functionally graded metallic syntactic foam. The investigated foams are manufactured while using infiltration casting where molten A356 aluminum flows into the interstitial voids of packed expanded perlite (EP) particle beds. The partial pre-compaction of particle beds enables the creation of distinct and reproducible density gradients within the syntactic foam. In this study, the s les are produced using four gradually increasing compaction forces and are compared to non-compacted s les. X-ray imaging is used to detect the resulting spatial variation of foam density. In addition, quasi-static compression tests are performed to determine the mechanical foam properties. The results suggest that particle pre-compaction is an efficient tool for tailoring the density and mechanical properties of these novel functionally graded materials.
Publisher: American Chemical Society (ACS)
Date: 03-09-2009
DOI: 10.1021/JA904901D
Abstract: Nanocomposition of molecular crystal ammonia borane (AB) by embedding it in mesoporous silica leads to a remarkable enhancement of the hydrogen storage properties. To investigate the nature of a nanophase AB, we used atomic pair distribution function (PDF) analysis of synchrotron X-ray powder diffraction data to follow the structural evolution of AB embedded within MCM-41 at temperatures ranging from 80 to 300 K. We found that the nanophase AB residing within the mesoporous scaffold does not undergo the structural phase transition at 225 K that was observed in the neat molecular crystal. Rather, it stays in the tetragonal phase over a wide temperature range of 110 to 240 K and starts to lose structural correlation above 240 K. This finding strongly suggests that nanoconfinement of AB within mesoporous scaffolds stabilizes the high-temperature disordered tetragonal phase at a much lower temperature. PDF analyses of composite materials composed of excess AB (i.e., AB:MCM-41 > 1:1) indicates that the excess AB forms aggregates outside the mesoporous scaffold and that these aggregates have structural properties similar to neat AB, that is, the orthorhombic-to-tetragonal structural phase transition is observed at 225 K upon warming. These results may provide important insight into the mechanism behind the enhanced hydrogen storage properties of this system.
Publisher: Elsevier BV
Date: 10-2014
Publisher: MDPI AG
Date: 13-09-2017
DOI: 10.3390/MA10091073
Abstract: Metal matrix syntactic foams have been fabricated via counter-gravity infiltration of a packed bed of recycled expanded glass particles (EG) with A356 aluminum alloy. Particle shrinkage was studied and has been utilized to increase the particles’ strength and tailor the mechanical properties of the expanded glass/metal syntactic foam (EG-MSF). The crushing strength of particles could be doubled by shrinking them for 20 min at 700 °C. Owing to the low density of EG (0.20–0.26 g/cm3), the resulting foam exhibits a low density (1.03–1.19 g/cm3) that increases slightly due to particle shrinkage. Chemical and physical analyses of EG particles and the resulting foams were conducted. Furthermore, metal syntactic foam s les were tested in uni-axial compression tests. The stress-strain curves obtained exhibit three distinct regions: elastic deformation followed by a stress plateau and densification commencing at 70–80% macroscopic strain. Particle shrinkage increased the mechanical strength of the foam s les and their average plateau stress increased from 15.5 MPa to 26.7 MPa.
Publisher: Springer Science and Business Media LLC
Date: 04-01-2016
Publisher: MDPI AG
Date: 20-11-2020
DOI: 10.3390/MET10111545
Abstract: Cellular solids and porous metals have become some of the most promising lightweight multifunctional materials due to their superior combination of advanced properties mainly derived from their base material and cellular structure [...]
Publisher: Elsevier BV
Date: 12-2014
Publisher: Wiley
Date: 10-2009
Publisher: Elsevier BV
Date: 04-2009
Publisher: Wiley
Date: 03-2008
Publisher: Wiley
Date: 09-2006
Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 04-2015
Publisher: Informa UK Limited
Date: 11-05-2012
Publisher: Elsevier BV
Date: 06-2013
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 09-2013
Publisher: Wiley
Date: 23-01-2008
Publisher: Elsevier BV
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 05-2005
Publisher: Trans Tech Publications, Ltd.
Date: 03-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.283-286.13
Abstract: In this paper, we review the recent developed method based around lattice-based random walks and the Monte Carlo method. This method, which is now called the Lattice Monte Carlo method, permits complex phenomenological problems in diffusion, thermal conductivity and elasticity to be addressed. It is shown how the effective mass diffusivity, thermal diffusivity/thermal conductivity and the bulk modulus in composites can be calculated and also how concentration profiles and temperature profiles can be determined in situations where the diffusivity depends on position and concentration and the thermal conductivity depends on position and temperature respectively.
Publisher: MDPI AG
Date: 30-05-2012
DOI: 10.3390/MET2020113
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 05-2010
Publisher: Elsevier BV
Date: 08-2012
Publisher: WIT Press
Date: 16-12-2014
DOI: 10.2495/ESUS140411
Publisher: IOP Publishing
Date: 18-10-2018
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.1476
Abstract: The Lattice Monte Carlo (LMC) method recently developed by the authors is an unusually powerful and flexible method in which a given phenomenological thermal or mass transport problem is mapped onto a fine-grained lattice which is then analyzed with discrete random walk methods. We provide an overview of the LMC method. For mass diffusion we highlight the addressing of diffusion with reversible reaction. For thermal transport we highlight a calculation of the effective thermal conductivity of sintered hollow sphere structures making use of CT scans of actual material as well as the determination of temperature profiles in phase-change composites.
Publisher: Elsevier BV
Date: 02-2013
Publisher: Trans Tech Publications, Ltd.
Date: 04-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.297-301.154
Abstract: Heat sinks enable the storage of energy that would otherwise be lost, thus ensuring significant energy-savings and fewer greenhouse gas emissions. Heat sinks also play the major role in the efficient temperature control of devices such as batteries. In principle, any material can act as a heat sink – traditionally, copper is used for many applications. However, copper is relatively expensive, has a high density and only a limited energy storage capacity. In contrast, a phase-change material (PCM) allows in effect an additional storage of energy through its phase change thus greatly increasing the achievable energy density. The aim of this work is the numerical analysis of the transient heat transfer in composite heat sinks containing phase-change materials. For the first time, a recently formulated Lattice Monte Carlo Method is applied to determine temperature distributions and the amount of energy transferred versus time in phase change materials.
Publisher: MDPI AG
Date: 08-08-2017
DOI: 10.3390/MA10080922
Publisher: Informa UK Limited
Date: 24-03-2009
Publisher: Elsevier BV
Date: 04-2012
Publisher: Wiley
Date: 04-2008
Publisher: MDPI AG
Date: 07-03-2019
DOI: 10.3390/MA12050792
Abstract: Zinc alloy (ZA27) syntactic foams (SF) were manufactured using expanded perlite (EP) particles and counter-gravity infiltration casting. Due to a variation of the metallic matrix content, the density of the produced foam s les varied from 1.78 to 2.03 g·cm−3. As-cast and solution heat-treated s les were tested to investigate the compressive properties of the ZA27 syntactic foam. To this end, quasi-static compression tests were conducted. In addition, microstructural analysis of the as-cast and heat-treated syntactic foams was carried out using scanning electron microscopy. The results indicate that the heat treatment alters the microstructure of the ZA27 alloy matrix from a multiphase dendrite to a spheroidized microstructure with improved ductility. Moreover, the heat treatment considerably enhances the energy absorption and plateau stress ( σ pl ) of the syntactic foam. Optical analysis of the syntactic foams under compression shows that the dominant deformation mechanism of the as-cast foams is brittle fracture. In comparison, the heat-treated s les undergo a more ductile deformation.
Publisher: Wiley
Date: 03-2009
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 11-2015
Publisher: SAGE Publications
Date: 10-07-2019
Abstract: Perlite–metal syntactic foam is a low-cost cellular metal intended for use in automotive impact protection. To test the viability of the material a 2.5 ton drop test was conducted. Impact mass and energy were selected to replicate the conditions of a frontal impact between a large passenger vehicle and a crash cushion. A hollow syntactic foam cylinder was manufactured to decelerate the drop weight in a controlled manner. Accelerometers and high-speed imaging were utilized to evaluate the performance of the energy absorbing element.
Publisher: MDPI AG
Date: 11-08-2023
DOI: 10.3390/MET13081440
Abstract: The aim of this study was to investigate the potential application of metal foams in shell-tube recuperators. A356 aluminium foam was cast around the internal and external surfaces of a thin-walled copper tube to enhance heat transfer between separated water streams at different temperatures. The results demonstrated that the aluminium foam drastically increased heat transfer efficiency due to its large volumetric surface area and high thermal conductivity. In the shell-tube foam recuperators, a maximum heat transfer efficiency of 48.1% was observed, compared to only 12.2% for a single copper tube without metal foam. The pressure drop across the external foam increased with the flow rate, from an average value of 1.19 kPa at 1.0 L/min to 7.36 kPa at 3.0 L/min. These findings suggest that metal foams have great potential for use in shell-tube recuperators, which could significantly improve the efficiency of heat transfer in various industrial and engineering applications.
Publisher: Begell House
Date: 2012
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 04-2008
Publisher: Trans Tech Publications, Ltd.
Date: 07-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.597.121
Abstract: This manuscript investigates the compressive properties of Corevo ® foam. Corevo ® foam is a cellular metal manufactured by the infiltration casting of salt dough with aluminium. Corevo ® foam s les with different porosities are tested by using quasi-static compression loading. Their mechanical properties (i.e.: effective Young’s modulus, Poisson’s ratio, initial yield stress and material yield stress) are then compared to reveal the importance of the density difference. In addition, three-dimensional finite element analysis is performed on models generated from micro-computed tomography (μCT). The results of two different pore sizes are obtained and compared in the scope of this work. These numerical results are verified by comparison with the experimental analysis. A sound agreement is found. Numerical analysis in this work also includes the investigation of the mechanical material anisotropy and plastic deformation.
Publisher: Wiley
Date: 12-2010
Publisher: Elsevier BV
Date: 06-2014
Publisher: Wiley
Date: 18-10-2011
Publisher: Springer Science and Business Media LLC
Date: 09-2015
DOI: 10.1007/S10856-015-5560-X
Abstract: This paper addresses the mechanical behavior of robocast PCL-Bioglass(®) scaffolds. These structures can be used as 3rd generation implants in tissue engineering to support the regrowth of damaged tissue, in particular bone. After successful tissue regeneration the scaffolds slowly dissolve leaving no foreign material permanently inside the body. However, to avoid mechanical separation from surrounding tissue they must exhibit similar mechanical properties. The present study introduces a detailed numerical study focusing on the determination of effective mechanical material properties, their anisotropy, and mechanical degradation due to scaffold resorption. In order to accurately capture the complex scaffold geometry, micro-computed tomography scans of actual s les are conducted. The resulting three-dimensional data are directly converted into finite element calculation models. Numerical compressive tests of these unmodified models are repeated for three perpendicular directions to investigate mechanical anisotropy, after which the effect of scaffold degradation due to exposure to body fluid is simulated. To this end, two different resorption models, namely surface erosion and bulk degradation, are applied to the micro-computed tomography data. The modified geometry data are then converted into calculation models and numerical compression tests then allow the prediction of the mechanical properties of partially resorbed scaffolds.
Publisher: Wiley
Date: 27-10-2010
Publisher: Trans Tech Publications Ltd.
Date: 25-08-2008
Publisher: Elsevier BV
Date: 07-2011
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.1500
Abstract: This work addresses the numerical analysis of anisotropic composite structures for thermal energy storage and temperature stabilization. The basic idea of heat sink composites is the combination of metallic matrices for fast energy transfer with phase change materials for thermal energy storage. Anisotropic matrices, such as lotus-type structures, allow for increased control of the thermal energy flow, without the necessity of additional thermal insulation. As an ex le, thermal energy can be directed towards a surface cooled by convection and excess energy is stored in the phase-change material. Computed tomography data of copper lotus-type material is used for the generation of the numerical calculation models. Due to its particular meso-structure, this material is characterised by strongly anisotropic properties. The void space of this cellular metal is filled with the phase-change material paraffin in order to enhance the energy storage capacity. A recently extended Lattice Monte Carlo method is used to evaluate the anisotropic thermal properties of these promising materials.
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.EXGER.2019.01.003
Abstract: To evaluate the effects of 12-weeks of strength training on endothelial function and inflammatory markers in elderly in iduals with T2DM. Forty-four elderly patients with T2DM were screened for participation. After completion of the baseline assessment, participants were randomly assigned to either the resistance training group (RT) or an active control group (AC). Inflammatory (TNF-α, IL-6, IL-1β, IL-10 and CRP) and blood lipid profiles, glycated hemoglobin, basal artery diameter and flow mediated dilation were evaluated before and after the intervention. Comparisons between groups were obtained from the generalized estimation equation and all tests were two-tailed and the alpha level for significance set at 0.05. TNF-α and IL-1β were decreased in both groups, while no interactions were found for flow mediated dilation and basal artery diameter. No significant differences were found for blood lipid profile and glycated hemoglobin for both groups after the intervention period. No significant changes were found between the RT and AC groups, regarding inflammatory profile and endothelial function, which does not prove the superiority of this intervention model in the studied period.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Wiley
Date: 08-06-2010
Publisher: Trans Tech Publications Ltd.
Date: 15-08-2007
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 05-2009
Publisher: SAGE Publications
Date: 22-09-2017
Abstract: The micro-structure and mechanical properties of lightweight porous foams synthesized by dispersing expanded perlite particles (expanded siliceous volcanic glass) in a matrix of epoxy resin were examined. Foams were fabricated with three distinct particle size ranges and, within each size, s les covered a density range of 0.15–0.45 g/cm 3 . The effects of particle size variation on compressive strength, effective elastic modulus, and modulus of toughness were investigated. An upper and a lower bound were estimated for the elastic modulus of particles in EP/epoxy foams. EP/epoxy foams showed Reuss-like behaviour similar to metals but atypical of non-plastic materials. In addition, results illustrated the significant contribution of the expanded perlite particles in the effective elastic modulus of the foams. Micro-structure of expanded perlite particles was examined and related to their macroscopic properties via two geometrical relationships. Post-test microscopic observations coupled with macroscopic observations taken during the test were used to understand the effect of particle size on the behaviour of the foams under compressive load. Observations revealed the presence of three different failure modes for all foams regardless of their particle size and density however, the strain to activate each mode was different for each foam type.
Publisher: MDPI AG
Date: 30-05-2020
DOI: 10.3390/MET10060726
Abstract: The paper presents a brief review of the main experimental and numerical techniques and standards to investigate and quantify the structural, mechanical, thermal, and acoustic properties of cellular metals. The potential of non-destructive techniques, such as X-ray computed tomography and infrared thermography are also presented.
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 2010
Publisher: Wiley
Date: 10-2005
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 06-2019
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 06-2014
Publisher: Trans Tech Publications Ltd.
Date: 15-08-2007
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 02-2012
Publisher: Springer Berlin Heidelberg
Date: 2011
DOI: 10.1007/8611_2010_6
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 09-2019
Publisher: Trans Tech Publications, Ltd.
Date: 04-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.297-301.1226
Abstract: Recently, the transition point between the Harrison Type-A and Type-B kinetics regimes as well as the emerging intermediate AB transition regime have been analysed in detail by making use of Lattice Monte Carlo (LMC) simulations of tracer depth concentration profiles as a function of diffusion time and distance between grain boundaries e.g. [1-3]. In the present study, we analyse Harrison Type-B to Type-C kinetics regimes in the transient grain boundary diffusion problem using the parallel slabs model and LMC numerical simulation. The transition point where the Harrison Type-B kinetics regime last occurs (transition point between the Harrison Type-B kinetics and the Type-BC kinetics) is estimated at (= 0.5δ(Dlt)-1/2) = 0.1. The Harrison Type-C grain boundary diffusion kinetics regime is also analysed using LMC simulated concentration depth profiles. The transition point where the Harrison Type-C kinetics regime first occurs (transition point between the Type-BC kinetics and the Harrison Type-C kinetics) is estimated at = 5.0. Therefore an intermediate Type-BC regime can be expected to occur between 0.1 5.0. Preliminary results for the cubic grain model show that the interval for the intermediate Type-BC regime is somewhat narrower for this model and occurs at 0.5 5.0.
Publisher: Walter de Gruyter GmbH
Date: 20-01-2017
DOI: 10.1515/POLYENG-2016-0263
Abstract: The anisotropic mechanical properties of parts that are fabricated using acrylonitrile butadiene styrene (ABS) polymer relative to part-built orientation employing the fused deposition modelling process are reported in this work. ABS plus -P430 polymer was used to investigate the effects of infill orientation on the parts’ mechanical properties under tensile and compression loading. Results revealed that infill orientation strongly affected the tensile properties of fabricated ABS s les. Specifically, the values for Young’s modulus ranged from ~1.5 to ~2.1 GPa, ultimate tensile strength from ~12.0 to ~22.0 MPa, yield strength from ~1.0 to ~21.0 MPa, and elongation-at-break from ~0.2 to ~4.8% for different infill orientations. S les with infill orientation aligned to the vertical (i.e. Z -) axis displayed the highest values relative to all other infill orientations investigated. Mechanical properties anisotropy was lower for parts under compressive loading, such that the Young’s modulus, ultimate compressive and yield strength were weakly correlated with infill orientation apart from s les whose built orientation was aligned at 45° to the vertical Z -axis. The latter s les displayed inferior mechanical properties under all compressive tests. The effects of s le gauge thickness on tensile properties and ABS s le micro- and bulk- hardness with respect to infill orientation are also discussed.
Publisher: Wiley
Date: 05-2011
Publisher: Elsevier BV
Date: 04-2012
Publisher: MDPI AG
Date: 20-12-2018
DOI: 10.3390/MA12010003
Abstract: In this study, activated carbon (AC) particles were combined with AZ91 alloy to manufacture a magnesium syntactic foam. This novel lightweight foam has a very low density, in the range of 1.12–1.18 gcm−3. The results show that no chemical reaction occurred between the AZ91 matrix and the activated carbon particles. The mechanical properties of the foam were evaluated under quasi-static compression loading conditions, and showed a consistent trend for the energy absorption of the fabricated AZ91–AC syntactic foams. The deformation mechanism of s les was a brittle fracture mode with the formation of shear bands during the fracture of all s les.
Publisher: Trans Tech Publications Ltd.
Date: 15-08-2007
Publisher: Elsevier BV
Date: 09-2011
Publisher: Trans Tech Publications, Ltd.
Date: 03-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.309-310.9
Abstract: The location of the transition points for the three main Harrison’s kinetics regimes (Type-A, B and C) for the measurement of grain boundary diffusivities from tracer concentration depth profiles (self-diffusion) has been extensively studied in (Divinski et al. Zeit. Metallk, 2002, Belova and Murch, Phil. Mag, 2001, 2009 Defect and Diffusion Forum, 2006, 2008, 2009) by making use of the phenomenological Lattice Monte Carlo numerical method. Those locations are mainly dependent on the dimensionality of the problem. For the case of impurity grain boundary diffusion, the segregation effect is very important. In the present study, the influence of segregation on the transition points is investigated for the parallel slab model (2-dimensional) of the grain boundary diffusion problem by making use of the tracer-type solution to the equivalent diffusion problem. It is shown that the Type-B regime is most likely not realized for the cases of fine-grain material with a strong segregation effect present.
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.MSEC.2015.07.063
Abstract: This paper addresses the mechanical characterization of polycaprolactone (PCL)-bioglass (FastOs®BG) composites and scaffolds intended for use in tissue engineering. Tissue engineering scaffolds support the self-healing mechanism of the human body and promote the regrowth of damaged tissue. These implants can dissolve after successful tissue regeneration minimising the immune reaction and the need for revision surgery. However, their mechanical properties should match surrounding tissue in order to avoid strain concentration and possible separation at the interface. Therefore, an extensive experimental testing programme of this advanced material using uni-axial compressive testing was conducted. Tests were performed at low strain rates corresponding to quasi-static loading conditions. The initial elastic gradient, plateau stress and densification strain were obtained. Tested specimens varied according to their average density and material composition. In total, four groups of solid and robocast porous PCL s les containing 0, 20, 30, and 35% bioglass, respectively were tested. The addition of bioglass was found to slightly decrease the initial elastic gradient and the plateau stress of the biomaterial scaffolds.
Publisher: Elsevier BV
Date: 05-2011
Publisher: SAGE Publications
Date: 13-08-2009
Abstract: Porous composite materials constitute an innovative group of lightweight materials which combine high specific stiffness, good d ing properties, and thermal insulation with the ability to absorb large amounts of energy at a low constant stress level. In the scope of this study, adhesively bonded metallic hollow sphere structures (MHSS) fully embedded within the adhesive matrix are considered with aim to determine their macroscopic behavior under uniaxial impact loading conditions by means of parametric computational simulations. The base material properties have been determined by quasi-static and dynamic experiments. Three topologies of syntactic hollow sphere structures of various dimensions are considered, namely the cubic primitive, the body centered cubic and the face centered cubic topology. Results of computational simulations show significant influence of topology and strain rate sensitivity on the composite structure behavior, while the influence of metallic hollow sphere wall thickness is less pronounced. Computational simulations show that it is possible to combine the MHSS topology, metallic hollow sphere wall thickness and strain rate sensitivity to achieve any desired dynamic response of MHSS adapted to a given engineering problem.
Publisher: SAGE Publications
Date: 06-06-2017
Abstract: A novel type of economical lightweight foam with density from 0.15 to 0.45 g/cm 3 was made from a high volume fraction of expanded volcanic glass (perlite) in an epoxy matrix. The compressive strength, effective elastic modulus, and modulus of toughness of the foams all increased with the foam density. The strength increased linearly, peaking at 1.7 MPa whereas the effective elastic modulus and modulus of toughness increased at parabolically increasing and decreasing rates, respectively. The specific compressive stress of the newly developed foam in the density range of 0.3–0.44 g/cm 3 is comparable with foams made from alumina, aluminium–silicon carbide, closed cell phenolic resin, and closed cell polypropylene. Post-test SEM observations coupled with photogrammetry during the tests revealed three different failure modes: longitudinal splitting, shear failure, and compression failure were present over the whole density range. The material was found to be a good candidate for the stiffening cores within sandwich panels.
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 04-2022
Publisher: Elsevier BV
Date: 05-2019
Publisher: MDPI AG
Date: 12-08-2021
DOI: 10.3390/MET11081277
Abstract: This study investigates the heat transfer performance of a novel ZA27 metal foam heat exchanger. An open-celled metal foam is combined with a thin-walled copper tube in a single-step casting process. The heat transfer between two separated water streams flowing through the copper tube and foam, respectively, is measured and compared to an equivalent shell tube heat exchanger arrangement. Heat transfer enhancement of up to 71% and a heat transfer rate exceeding 30 kW are observed and attributed to the increased surface area of the metallic foam. However, overall performance was limited by the inefficient heat transfer between the internal mass stream and the copper tube.
Publisher: ACM
Date: 12-11-2011
Publisher: Springer Science and Business Media LLC
Date: 11-2006
Publisher: Elsevier BV
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 14-07-2014
DOI: 10.1007/S10856-014-5264-7
Abstract: Tissue engineering scaffolds are designed to support tissue self-healing within physiological environments by promoting the attachment, growth and differentiation of relevant cells. Newly formed tissue must be supplied with sufficient levels of oxygen to prevent necrosis. Oxygen diffusion is the major transport mechanism before vascularization is completed and oxygen is predominantly supplied via blood vessels. The present study compares different designs for scaffolds in the context of their oxygen diffusion ability. In all cases, oxygen diffusion is confined to the scaffold pores that are assumed to be completely occupied by newly formed tissue. The solid phase of the scaffolds acts as diffusion barrier that locally inhibits oxygen diffusion, i.e. no oxygen passes through the scaffold material. As a result, the oxygen diffusivity is determined by the scaffold porosity and pore architecture. Lattice Monte Carlo simulations are performed to compare the normalized oxygen diffusivities in scaffolds obtained by the foam replication (FR) method, robocasting and sol-gel foaming. Scaffolds made by the FR method were found to have the highest oxygen diffusivity due to their high porosity and interconnected pores. These structures enable the best oxygen supply for newly formed tissue among the scaffold types considered according to the present numerical predictions.
Publisher: Elsevier BV
Date: 02-2014
Publisher: Elsevier BV
Date: 02-2016
Publisher: Trans Tech Publications Ltd.
Date: 15-08-2007
Publisher: IEEE
Date: 06-2010
Publisher: Springer Science and Business Media LLC
Date: 06-2015
DOI: 10.1007/S10856-015-5531-2
Abstract: This paper addresses the computation of the effective diffusivity in new bioactive glass (BG) based tissue engineering scaffolds. High diffusivities facilitate the supply of oxygen and nutrients to grown tissue as well as the rapid disposal of toxic waste products. The present study addresses required novel types of bone tissue engineering BG scaffolds that are derived from natural marine sponges. Using the foam replication method, the scaffold geometry is defined by the porous structure of Spongia Agaricina and Spongia Lamella. These sponges present the advantage of attaining scaffolds with higher mechanical properties (2-4 MPa) due to a decrease in porosity (68-76%). The effective diffusivities of these structures are compared with that of conventional scaffolds based on polyurethane (PU) foam templates, characterised by high porosity (>90%) and lower mechanical properties (>0.05 MPa). Both the spatial and directional variations of diffusivity are investigated. Furthermore, the effect of scaffold decomposition due to immersion in simulated body fluid (SBF) on the diffusivity is addressed. Scaffolds based on natural marine sponges are characterised by lower oxygen diffusivity due to their lower porosity compared with the PU replica foams, which should enable the best oxygen supply to newly formed bone according the numerical results. The oxygen diffusivity of these new BG scaffolds increases over time as a consequence of the degradation in SBF.
Publisher: Elsevier BV
Date: 03-2008
Start Date: 06-2013
End Date: 11-2016
Amount: $305,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2010
End Date: 02-2014
Amount: $330,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2017
End Date: 03-2021
Amount: $309,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2015
End Date: 06-2018
Amount: $335,500.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2010
End Date: 06-2013
Amount: $340,000.00
Funder: Australian Research Council
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