ORCID Profile
0000-0002-9606-023X
Current Organisations
Zhejiang Gongshang University
,
Macquarie University
,
University of South Australia
,
Natural History Museum
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Publisher: Oxford University Press (OUP)
Date: 14-02-2019
Publisher: Springer Science and Business Media LLC
Date: 14-06-2018
DOI: 10.1007/S10661-018-6744-X
Abstract: Trace metals occur at various concentrations in all wetlands. Their proliferation, chemical speciation, mobility and bioavailability are dependent on the redox potential (Eh), pH and the presence of organic and inorganic adsorption surfaces and co-precipitating metals. Consequently, changes in these key parameters have the potential to alter the fate of the dominant trace metal species in the sediment. An imposition of preload surcharge is a technique use in geotechnical engineering to improve in the strength and load carrying capacity of waterlogged sediments. The soil strength improvement is effected through the expulsion of porewater from the sediment. The imposition of surcharge over wetland sediments has the potential to create oxygen-deficient condition within the sediment, and cause pH, temperature, redox, EC and salinity changes in the sediment, which would impact on the mobilisation, chemical speciation, mobility and bioavailability of dominant toxic trace metals and their toxicity in the sediment. In the present work, a case study of the impact of preload surcharge on the proliferation, chemical speciation, mobilisation, mobility and bioavailability of arsenic, chromium, cobalt, copper and zinc in a naturally occurring pyrite-rich sediment is presented. The imposition of preload surcharge over the pyrite-rich sediment was accompanied by changes in the redox dynamics of the sediment, with multi-facet impact on the concentration, mobilisation and bioavailability of toxic trace metals, their redox transformation between oxidation states and on the toxicity within and outside the sediment environment.
Publisher: Elsevier BV
Date: 08-2009
Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-03-2020
Abstract: Lambert et al . question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in hibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and h ers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 hibian species.
Publisher: Wiley
Date: 2005
DOI: 10.1002/SIA.2067
Publisher: Elsevier BV
Date: 02-2006
Publisher: Elsevier BV
Date: 04-2022
Publisher: Elsevier BV
Date: 12-2004
Publisher: American Chemical Society (ACS)
Date: 07-11-2008
DOI: 10.1021/ES801767B
Abstract: Despite the existence of many single ion sorption studies on iron and aluminum oxides, fewer studies have been reported that describe cosorption reactions. In this work, we present an in situ ATR FTIR study of synergistic adsorption of sulfate (SO4) and copper (Cu) on goethite, which is representative of the minerals and ions present in mine wastes, acid sulfate soils, and other industrial and agricultural settings. Sulfate adsorption was studied as a function of varying pH, and as a function of increasing concentration in the absence and presence of Cu. The presence of Cu ions in solution had a complex effect on the ability of SO4 ions to be retained on the goethite surface with increasing pH, with complete desorption occurring near pH 7 and 9 in the absence and presence of Cu, respectively. In addition, Cu ions altered the balance of inner vs outer sphere adsorbed SO4. The solid phase partitioning of SO4 at pH 3 and pH 5 was elevated by the presence of Cu in both cases Cu increased the affinity of SO4 for the goethite surface. Complementary ex situ sorption edge studies of Cu on goethite in the absence and presence of SO4 revealed that the Cu adsorption edge shifted to lower pH (6.3 --> 5.6) in the presence of SO4, consistent with a decrease of the electrostatic repulsion between the goethite surface and adsorbing Cu. Based on the ATR FTIR and bulk sorption data we surmise that the cosorption products of SO4 and Cu at the goethite-water interface were not in the nature of ternary complexes under the conditions studied here. This information is critical for the evaluation of the onset of surface precipitates of copper-hydroxy sulfates as a function of pH and solution concentration.
Publisher: Elsevier BV
Date: 03-2003
Publisher: Elsevier BV
Date: 11-2023
Publisher: Elsevier BV
Date: 03-2013
Publisher: Informa UK Limited
Date: 23-11-2007
DOI: 10.1080/10937400701389917
Abstract: This article reviews evidence that suggests Cu and Zn concentrations are not altered significantly by exogenous processes and may be useful in applications of hair analysis. The review attempts to identify what Cu and Zn concentrations may actually indicate biogenically and investigates the mechanisms by which they are incorporated into hair. Associations with specific hair components are proposed and avenues for development as a bioindicator are identified. Areas of research that offer promise in application or confirming the use of Cu and Zn are also indicated. Correlations and relationships with other health disorders are reviewed. Endogenous blood concentrations may also explain alterations in hair structure relating to breast cancer.
Publisher: Elsevier BV
Date: 10-2009
Publisher: Elsevier BV
Date: 10-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 22-07-2014
DOI: 10.1039/C4CC04470C
Abstract: In the quest for solutions to meeting future energy demands, solar fuels play an important role. A particularly promising ex le is photocatalysis since even incremental improvements in performance in this process are bound to translate into significant cost benefits. Here, we report that semiconducting and high surface area 3D silicon replicas prepared from abundantly available diatom fossils sustain photocurrents and enable solar energy conversion.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 06-2019
Publisher: American Physical Society (APS)
Date: 09-11-2005
Publisher: Informa UK Limited
Date: 23-05-2022
Publisher: Elsevier BV
Date: 06-2022
Publisher: MDPI AG
Date: 11-04-2023
Abstract: The harsh and hostile internal environment of semi-autogenous (SAG) mills renders real-time monitoring of some critical variables practically unmeasured. Typically, feed size fractions are known to cause mill fluctuations and impede the consistent processing behaviour of ores. There is, therefore, the need for continuous monitoring of mill parameters for optimal operation. In this paper, an acoustic-based sensing method is employed to estimate, in real time, a snapshot of the different feed size fractions presented to a laboratory-scale SAG mill. Employing the MATLAB 2020b programme, the mill acoustic signal is processed using various transform techniques such as power spectral density estimate (PSDE) by Welch’s method, discrete wavelet transform (DWT), wavelet packet transform (WPT), empirical mode decomposition (EMD), and variational mode decomposition (VMD). Different fractional bandpowers are obtained from the PSDE spectrum, while the statistical root mean square values are further extracted from DWT, WPT, EMD, and VMD as feature vectors. The features are used as input features in different machine-learning classification algorithms for different mill feed size fractions predictions. The various transform techniques and feed size fraction predictions are evaluated using the various performance indicators obtained from the confusion matrix such as accuracy, precision, sensitivity and F1 score. The study showed that the acoustic signal feature extraction techniques used in conjunction with the Support Vector Machine (SVM), linear discriminant analysis (LDA), and ensemble with subclass discriminant machine learning algorithms demonstrated improved performance for predicting feed size variations.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 08-2018
Publisher: Springer Science and Business Media LLC
Date: 16-07-2009
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 08-2000
Publisher: Mineralogical Society of America
Date: 11-2011
DOI: 10.2138/AM.2011.3691
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 08-2021
Publisher: AIP Publishing
Date: 08-1993
DOI: 10.1063/1.354819
Abstract: The effects of 2 MeV H+, B+, O++, and Au++ ion irradiation on the adhesion energy of thin Cu films deposited on sapphire has been investigated. Adhesion energy was measured by the observation of the resultant laterally segregated Cu particle shape after vacuum annealing. Film/substrate adhesion is shown to increase with increasing ion dose and exhibits saturation behavior at high fluences. The adhesion energy is shown to be a linear function of the electronic stopping over the entire ion mass range—suggesting a purely electronic mechanism for the adhesion enhancement in this ion energy regime.
Publisher: The Chemical Society of Japan
Date: 05-10-2012
DOI: 10.1246/CL.2012.1247
Publisher: Springer Science and Business Media LLC
Date: 28-11-2009
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 03-1985
Publisher: Elsevier
Date: 2005
Publisher: Elsevier BV
Date: 11-2000
Publisher: Elsevier BV
Date: 03-2005
DOI: 10.1016/J.CHEMOSPHERE.2004.09.087
Abstract: Synchrotron X-ray fluorescence has been used to study the distribution of lead in a hair s le collected from a lead smelter worker. A mathematical model was used to imitate the transverse scan signal based on the analysis volume and concentration profiles. The results suggest that the Pb originates both from ingestion and environmental exposure, however direct deposition from the environment is the more important source of hair lead. The model could apply equally to any other analysis involving a thin cylindrical s le.
Publisher: Informa UK Limited
Date: 09-10-2020
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.SCITOTENV.2018.01.312
Abstract: Ammonia (NH
Publisher: Elsevier BV
Date: 12-2000
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 15-08-2005
Publisher: Elsevier BV
Date: 09-2000
Publisher: Informa UK Limited
Date: 2013
Publisher: Informa UK Limited
Date: 10-2013
Publisher: Oxford University Press (OUP)
Date: 17-01-2020
Publisher: MDPI AG
Date: 03-04-2014
DOI: 10.3390/NANO4020256
Publisher: Canadian Science Publishing
Date: 10-2007
DOI: 10.1139/V07-078
Abstract: Synchrotron XPS and Cu L 2,3 -edge NEXAFS spectroscopic data for a natural tetrahedrite surface prepared by fracture under UHV were in accord with the composition of the mineral and its expected semiconductivity. The 2p binding energy for the 6-coordinate S atoms was found to be not detectably greater than that for the 4-coordinate S atoms, and surface species were not clearly discernible in either surface-optimized S 2p or Cu 2p spectra. The Cu 2p and Cu L 2,3 -edge spectra indicated that all Cu in the mineral was indisputably Cu(I). The Cu L 2,3 -edge spectra of relatively pure natural sphalerite treated with mildly acidic aqueous cupric solution revealed the presence of Cu(II) in the outermost layer of the fracture surfaces, but it was concluded that most of the Cu near the surface of the mineral was in formal oxidation state Cu(I), albeit with higher than normal d 9 character. The Cu(I) absorption peak was at an energy much lower than for the tetrahedrite absorption edge, but still consistent with Cu(I) in 4-fold coordination by S. The Cu(II) was consistent with Cu bonded both to S atoms in the outermost layer of the sphalerite and to O atoms in chemisorbed water. S 2p spectra determined at different photon energies revealed high binding energy components arising from oligosulfide-like environments in the outermost layers, but not necessarily in a completely restructured lattice and not in a Cu oligosulfide only. The data indicated some loss of Zn in addition to the Zn that had been replaced by Cu in the outermost layers of the sulfide lattice. The presence of these oligosulfide-like environments precluded the detection of S with formal oxidation state greater than (-II) that might have arisen only from Cu(I) in the S lattice. No evidence was obtained for the presence of Cu(II) in a sulfide lattice, but it was not possible to exclude the possibility of a very low concentration because of the presence of the Cu(II) bonded to both S and O at the surface of the treated sphalerite.Key words: tetrahedrite, sphalerite, copper uptake, XPS, NEXAFS.
Publisher: Elsevier BV
Date: 08-2017
Publisher: Wiley
Date: 10-2007
Publisher: Elsevier BV
Date: 08-2009
Publisher: Elsevier BV
Date: 2012
Publisher: MDPI AG
Date: 03-02-2021
Abstract: Currently there are no available methods for in-line measurement of gas-liquid interfacial tension during the flotation process. Microfluidic devices have the potential to be deployed in such settings to allow for a rapid in-line determination of the interfacial tension, and hence provide information on frother concentration. This paper presents the development of a simple method for interfacial tension determination based on a microfluidic device with a flow-focusing geometry. The bubble generation frequency in such a microfluidic device is correlated with the concentration of two flotation frothers (characterized by very different adsorption kinetic behavior). The results are compared with the equilibrium interfacial tension values determined using classical profile analysis tensiometry.
Publisher: Elsevier BV
Date: 2011
Publisher: American Physical Society (APS)
Date: 29-12-2005
Publisher: The Electrochemical Society
Date: 16-04-2010
DOI: 10.1149/1.3367904
Abstract: Angle resolved X-ray photoelectron spectroscopy (ARXPS) and synchrotron XPS (SXPS) have been used to study the (110) surface of two Fe containing sphalerites cleaved in vacuo. The ARXPS S 2p and Zn 2p spectra collected from a low Fe (0.02 wt.%) sphalerite revealed a low binding energy peak when collected at low take off angles (20°). These peaks have been assigned as surface core-level shifts of ~ -0.46 eV and ~ +0.34 eV, respectively. The ARXPS and SXPS S 2p spectra collected from a high Fe (14.79 wt.%) sphalerite indicated the presence of a low binding energy peak resulting from a core level shift ~ -0.42 eV below the bulk S 2p line. A higher binding energy contribution, attributed to a second surface species, was found +0.47 eV above the bulk S 2p doublet. Comparison of the S 2p spectra collected from the two sphalerites, suggested that high Fe concentrations might induce surface reconstruction in the form of surface S dimers. The surface S dimers are likely to be concentrated at high energy step edges and defects.
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.ACA.2015.10.040
Abstract: Zero-valent iron nanoparticles (nZVI) have been widely tested as they are showing significant promise for environmental remediation. However, many recent studies have demonstrated that their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Both the mobility and reactivity of nZVI mainly depends on properties such as particle size, surface chemistry and bulk composition. In order to ensure efficient remediation, it is crucial to accurately assess and understand the implications of these properties before deploying these materials into contaminated environments. Many analytical techniques are now available to determine these parameters and this paper provides a critical review of their usefulness and limitations for nZVI characterisation. These analytical techniques include microscopy and light scattering techniques for the determination of particle size, size distribution and aggregation state, and X-ray techniques for the characterisation of surface chemistry and bulk composition. Ex le characterisation data derived from commercial nZVI materials is used to further illustrate method strengths and limitations. Finally, some important challenges with respect to the characterisation of nZVI in groundwater s les are discussed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2GC02214A
Abstract: Critical minerals have an irreplaceable role in the ongoing revolution in technology and using microfluidic continuous-flow technology for processing these minerals has potential solutions and benefits towards the ESG mining issues.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 12-2018
Publisher: Springer Science and Business Media LLC
Date: 21-08-2007
Publisher: Elsevier BV
Date: 07-2006
Publisher: American Chemical Society (ACS)
Date: 05-07-2011
DOI: 10.1021/NN2022974
Abstract: We discuss the use of quantum dots (QDs) in electro-optic devices. The focus of the article is on key problems in this area: the electronic and optical properties of QDs, dispersing QDs in polymers and the requirements for both, and QDs and polymer composites in devices such as solar cells, light-emitting devices, and detectors. The accompanying article by Geyer et al. in this issue of ACS Nano demonstrates an excellent ex le of a detector device, which also points to future directions for research in this field.
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 02-2006
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 03-2013
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 08-2013
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1016/J.FORSCIINT.2007.05.017
Abstract: The characterisation and comparison of pencil markings on paper is an area of questioned document analysis that has previously not received much attention. Despite this, there would be value in an examiner being able to analyse two pencil markings and coming to a conclusion about whether they were from a similar or different source. Previous studies have analysed raw materials and bulk pencil cores for purposes of characterisation and differentiation, but to date, no studies have successfully analysed pencil markings non-destructively off a paper substrate. In this work, pencils from a number of manufacturers were analysed by inductively coupled plasma mass spectrometry (ICP-MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Analysis of data using multivariate techniques (principal component analysis), showed that ToF-SIMS can successfully be used to analyse such pencil markings to deduce whether two markings can be differentiated, in terms of inorganic elemental composition. It was possible to discriminate between pencil markings from different manufacturers, and it was also indicated that pencils from the same manufacturer, but discrete batches, can be significantly different.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.CHEMOSPHERE.2009.03.010
Abstract: The consumption of arsenic (As) contaminated rice is an important exposure route for humans in countries where rice cultivation employs As contaminated irrigation water. Arsenic toxicity and mobility are a function of its chemical-speciation. The distribution and identification of As in the rice plant are hence necessary to determine the uptake, transformation and potential risk posed by As contaminated rice. In this study we report on the distribution and chemical-speciation of As in rice (Oryza sativa Quest) by X-ray fluorescence (XRF) and X-ray absorption near edge structure (XANES) measurements of rice plants grown in As contaminated paddy water. Investigations of muXRF images from rice tissues found that As was present in all rice tissues, and its presence correlated with the presence of iron at the root surface and copper in the rice leaf. X-ray absorption near edge structure analysis of rice tissues identified that inorganic As was the predominant form of As in all rice tissues studied, and that arsenite became increasingly dominant in the aerial portion of the rice plant.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2013
Publisher: Cold Spring Harbor Laboratory
Date: 23-05-2020
DOI: 10.1101/2020.05.22.110833
Abstract: High-quality and complete reference genome assemblies are fundamental for the application of genomics to biology, disease, and bio ersity conservation. However, such assemblies are only available for a few non-microbial species 1–4 . To address this issue, the international Genome 10K (G10K) consortium 5,6 has worked over a five-year period to evaluate and develop cost-effective methods for assembling the most accurate and complete reference genomes to date. Here we summarize these developments, introduce a set of quality standards, and present lessons learned from sequencing and assembling 16 species representing major vertebrate lineages (mammals, birds, reptiles, hibians, teleost fishes and cartilaginous fishes). We confirm that long-read sequencing technologies are essential for maximizing genome quality and that unresolved complex repeats and haplotype heterozygosity are major sources of error in assemblies. Our new assemblies identify and correct substantial errors in some of the best historical reference genomes. Adopting these lessons, we have embarked on the Vertebrate Genomes Project (VGP), an effort to generate high-quality, complete reference genomes for all ~70,000 extant vertebrate species and help enable a new era of discovery across the life sciences.
Publisher: American Chemical Society (ACS)
Date: 03-05-2012
DOI: 10.1021/LA300352F
Abstract: Methylated quartz surfaces are extensively used in colloid science for wettability studies and the control and impact of hydrophobicity in key physicochemical processes. In this study, time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used to correlate the surface chemistry of trimethylchlorosilane-methylated quartz surfaces with the contact angle. Models have been developed for the calculation of both advancing and receding contact angles based on measurements of the ToF-SIMS signals for SiC(3)H(9)(+) (TMCS) and Si(+) (quartz). These models enable the contact angle across surfaces and, more importantly, that of in idual particles to be determined on a micrometer scale. Distributions of contact angles in large ensembles of particles, therefore, can now be determined. In addition, from the ToF-SIMS analysis, the surface coverage of the methylated species can be quantitatively determined, in line with the Cassie equation. Moreover, advancing and receding contact angle maps can be calculated from ToF-SIMS images, and hence the variation in microscopic hydrophobicity (e.g., at the particle level) can be extracted directly from the images.
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 07-2015
Publisher: Wiley
Date: 06-1987
Publisher: American Chemical Society (ACS)
Date: 27-03-2012
DOI: 10.1021/JP300533M
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CE01325A
Abstract: A rapid microwave-assisted synthesis for nearly monodisperse CuInS 2 /ZnS nanocrystals (NCs) has been developed.
Publisher: Elsevier BV
Date: 12-2003
DOI: 10.1016/J.BBAGEN.2003.09.003
Abstract: Calcium distributions on internal and external surfaces of longitudinally sectioned hairs were analysed with Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Externally, calcium deposits were observed at the cuticle scale edges. Internal sections showed that the bulk of calcium exists within or just inside the cuticle layer. The medulla may or may not be enriched and other localised concentrations exist in one of two forms either associated with granular structures or the hair proteins. Calcium appears to show an affinity for proteins with low sulfur content.
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 07-2003
Publisher: American Chemical Society (ACS)
Date: 14-09-2011
DOI: 10.1021/IE101548F
Publisher: Elsevier BV
Date: 06-2001
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 06-2014
Publisher: Elsevier BV
Date: 03-2012
Publisher: MDPI AG
Date: 10-01-2019
Abstract: Conjugated polymers with stabilizing coordination units for single-site catalytic centers are excellent candidates to minimize the use of expensive noble metal electrode materials. In this study, conjugated metallopolymer, POS[Cu], was synthesized and fully characterized by means of spectroscopical, electrochemical, and photophysical methods. The copper metallopolymer was found to be highly active for the electrocatalytic hydrogen generation (HER) in an aqueous solution at pH 7.4 and overpotentials at 300 mV vs. reversible hydrogen electrode (RHE). Compared to the platinum electrode, the obtained overpotential is only 100 mV higher. The photoelectrochemical tests revealed that the complexation of the conjugated polymer POS turned its intrinsically electron-accepting (p-type) properties into an electron-donor (n-type) with photocurrent responses ten times higher than the organic photoelectrode.
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 09-2006
Publisher: American Chemical Society (ACS)
Date: 24-02-2010
DOI: 10.1021/LA904443S
Abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used as a technique to correlate the surface chemistry of chalcopyrite particles with their contact angle. Three particle sizes (20-38, 75-105, and 150-210 microm) were used, covering a range of contact angles between 20 and 90 degrees. Multivariate statistical techniques were applied to the ToF-SIMS data in order to identify structure in the data and the surface species contributing the most to surface chemistry and hence the hydrophobicity variation. A method to calculate the contact angle of chalcopyrite by ToF-SIMS surface analysis has been developed using only information from three secondary ions: oxygen, sulfur, and a thiol collector fragment. This approach is capable of determining the surface chemistry contribution to the contact angle of in idual mineral particles and the distribution of contact angles within a large ensemble of particles. Further measurements verified that the methodology can also be applied to flat surfaces, enabling rapid surface chemistry-hydrophobicity correlations to be made on a wide range of mineral and material systems.
Publisher: Springer Science and Business Media LLC
Date: 29-03-2015
DOI: 10.1007/S11356-013-1653-6
Abstract: In this study, two carbon materials [chicken manure biochar (CMB) and black carbon (BC)] were investigated for their effects on the reduction of hexavalent chromium [Cr(VI)] in two spiked [600 mg Cr(VI) kg(-1)] and one tannery waste contaminated [454 mg Cr(VI) kg(-1)] soils. In spiked soils, both the rate and the maximum extent of reduction of Cr(VI) to trivalent Cr [Cr(III)] were higher in the sandy loam than clay soil, which is attributed to the difference in the extent of Cr(VI) adsorption between the soils. The highest rate of Cr(VI) reduction was observed in BC-amended sandy loam soil, where it reduced 452 mg kg(-1) of Cr(VI), followed by clay soil (427 mg kg(-1)) and tannery soil (345 mg kg(-1)). X-ray photoelectron microscopy confirmed the presence of both Cr(VI) and Cr(III) species in BC within 24 h of addition of Cr(VI), which proved its high reduction capacity. The resultant Cr(III) species either adsorbs or precipitates in BC and CMB. The addition of carbon materials to the tannery soil was also effective in decreasing the phytotoxicity of Cr(VI) in mustard (Brassica juncea L.) plants. Therefore, it is concluded that the addition of carbon materials enhanced the reduction of Cr(VI) and the subsequent immobilization of Cr(III) in soils.
Publisher: Elsevier BV
Date: 2015
Publisher: Wiley
Date: 16-02-2008
Publisher: MDPI AG
Date: 27-08-2020
DOI: 10.3390/MIN10090759
Abstract: In our previous studies, we investigated the performance of a novel pneumatic planar magnetic separator (PMS) for the dry beneficiation of a selected magnetite ore. In the present study, we have extended the studies on the PMS with the focus on investigating how various PMS processing flowsheet configurations influence its performance. The outcomes were subsequently compared with those of a Davis tube recovery (DTR) tester. The study demonstrated that the use of PMS in the dry beneficiation of magnetite ores is feasible, and operating the PMS in different flowsheet configurations positively influences the magnetite concentrate grade and purity. Finally, the study showed that the PMS performance compares well with that of DTR and can potentially replace DTR in operations that are carried out in arid regions.
Publisher: Elsevier BV
Date: 11-2010
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 12-2015
Publisher: MDPI AG
Date: 27-06-2023
DOI: 10.3390/MIN13070868
Abstract: In a large-scale operation, feed ores are introduced into the AG/SAG mill in a continuous mode at a given flow rate to replace the discharging slurry. Nonetheless, the variations in the feed characteristics, typically hardness and size distribution, could cause sudden disruption to the mill operation. This would be challenging to detect in practice, owing to the hostile environment of the mill. In this work, an acoustic sensing-based monitoring technique was utilized in a laboratory-scale AG/SAG mill locked-cycle study to keep track of fluctuations caused by feed ore heterogeneity. Analysis of the recorded mill acoustic response using statistical root mean square (RMS) and mill discharge sizes showed that the introduction of fresh feed with varying hardness and size distribution considerably altered the mill product undersize of −150 μm and acoustic emission. Overall, the acoustic sensing technique demonstrated that the AG/SAG mill stability as well as disturbances caused by different feed size fractions and hardness can be monitored using the mill acoustic response, an indication of real-time monitoring and optimisation.
Publisher: Springer Science and Business Media LLC
Date: 02-02-2006
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 07-2013
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13595
Abstract: Cube-shaped magnetic iron oxide nanoparticles were synthesised and studied with the aim to achieve superior magnetic properties. This study describes a straightforward and simple synthesis method for preparing monodisperse 11–14-nm superparamagnetic iron oxide nanocubes via an ‘effective monomer’ growth mechanism. The as-synthesised nanoparticles are insoluble in water. However, substitution of the non-polar ligands of the particles using a new method that involved an ionic compound generated colloidally stable and water dispersible cube-shaped particles with a very small hydrodynamic diameter. The cubes displayed superior magnetic properties over spherical particles.
Publisher: American Vacuum Society
Date: 20-11-2020
DOI: 10.1116/6.0000685
Abstract: This study was undertaken to understand the extent and nature of problems in x-ray photoelectron spectroscopy (XPS) data reported in the literature. It first presents an assessment of the XPS data in three high-quality journals over a six-month period. This analysis of 409 publications showing XPS spectra provides insight into how XPS is being used, identifies the common mistakes or errors in XPS analysis, and reveals which elements are most commonly analyzed. More than 65% of the 409 papers showed fitting of XP spectra. An ad hoc group (herein identified as “the committee”) of experienced XPS analysts reviewed these spectra and found that peak fitting was a common source of significant errors. The papers were ranked based on the perceived seriousness of the errors, which ranged from minor to major. Major errors, which, in the opinion of the ad hoc committee, can render the interpretation of the data meaningless, occurred when fitting protocols ignored underlying physics and chemistry or contained major errors in the analysis. Consistent with other materials analysis data, ca. 30% of the XPS data or analysis was identified as having major errors. Out of the publications with fitted spectra, ca. 40% had major errors. The most common elements analyzed by XPS in the papers s led and researched at an online database, include carbon, oxygen, nitrogen, sulfur, and titanium. A scrutiny of the papers showing carbon and oxygen XPS spectra revealed the classes of materials being studied and the extent of problems in these analyses. As might be expected, C 1s and O 1s analyses are most often performed on sp2-type materials and inorganic oxides, respectively. These findings have helped focus a series of XPS guides and tutorials that deal with common analysis issues. The extent of problematic data is larger than the authors had expected. Quantification of the problem, examination of some of the common problem areas, and the development of targeted guides and tutorials may provide both the motivation and resources that enable the community to improve the overall quality and reliability of XPS analysis reported in the literature.
Publisher: Elsevier BV
Date: 15-10-2009
Publisher: Elsevier BV
Date: 02-2004
DOI: 10.1016/J.CHEMOSPHERE.2003.07.010
Abstract: Time of flight secondary ion mass spectroscopy has been used to study the metal distribution at the soil/root interface of tree roots extracted from smelter-impacted soils. The results, augmented by scanning electron microscopy, show that the technique is capable of resolving metal distributions at the cellular level. In addition, the distribution of metals between the root plaque and the root interior may be useful in interpreting local metal transport mechanisms.
Publisher: Elsevier BV
Date: 05-2004
Publisher: Elsevier BV
Date: 05-1998
Publisher: Elsevier BV
Date: 09-1999
Publisher: Elsevier BV
Date: 02-2005
DOI: 10.1016/J.SCITOTENV.2004.07.017
Abstract: Elemental distributions on whole and longitudinal sections of hairs plucked from the scalp were studied with the surface sensitive technique time-of-flight secondary ion mass spectrometry (ToF-SIMS). Endogenous and environmental influences on the distributions of elemental species were identified. The cuticle scales appear to play the major role in the accumulation of exogenous products. The functionality of the outer surfaces and scale edges each preferentially bind different elemental species. The majority of elements considered accumulated longitudinally on the outer surface of the hair above the scalp level. Internally, most elemental signals (especially Al) decreased longitudinally once exposed to the environment with the exception of Si, which showed an increase. Images of elemental distributions within the medulla suggest that regions of different reactivity exist and show a variable ability to accumulate elemental species. The greatest signal intensities were observed in the cuticle and medulla regions rather than the cortex. The cuticle is continually exposed to environmental contamination and the medulla may, or may not, exist in a hair. Therefore, the components of a hair that potentially contribute the most to the elemental concentrations (i.e. the cuticle and medulla) are also the most variable, and as such greatly complicate the interpretation of elemental concentrations in hair. Results also suggest that bleaching hair can enhance the accumulation of contaminants.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 06-2012
Publisher: Springer Science and Business Media LLC
Date: 14-07-2022
DOI: 10.1038/S41598-022-15663-Z
Abstract: Metal–organic frameworks (MOFs) with ratiometric sensing properties are desirable for many applications due to their intrinsic self-calibration. We report the re-assessment of the sensing properties of a MOF, originally reported as containing europium(III) and 2-hydroxyterephtalic acid, and having fluorescent ratiometric iron(III) sensing properties. Synchrotron single-crystal X-ray diffraction and proton nuclear magnetic resonance ( 1 H NMR) spectroscopy revealed that the MOF is composed of 2-methoxyterephthalate, not 2-hydroxyterephthalate as originally reported. We found that the MOF exhibits a sensor turn-off response towards Fe 3+ ion concentrations in the range 0.5–3.7 ppm (band 425 nm), and a turn-on response towards a decrease of pH from 5.4 to 3.0 (band 375 nm), both resulting from the addition of acidic Fe 3+ salt solution to a MOF suspension. Thus, the ratiometric sensing properties and the originally proposed mechanism no longer apply our work reveals a dynamic quenching mechanism for the fluorescence turn-off response due to the presence of Fe 3+ ions, and a ligand protonation mechanism for the turn-on response to a decrease in pH. Our work highlights the importance of a thorough investigation of the structure of any newly synthesized MOF, and, in the case of potential sensors, their selectivity and any environmental effects on their sensing behavior.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CP02797A
Abstract: Surface force measurements reveal that a small increase in surface charge enhance the long range hydrophobic attraction.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TA01821H
Abstract: Nickel oxide (NiO) is the most universally studied photocathode to date. We demonstrate that non-toxic CuInS 2 /ZnS NCs can be used to sensitise NiO photocathodes to achieve an (almost) all-inorganic system.
Publisher: Springer Science and Business Media LLC
Date: 13-03-2019
DOI: 10.1007/S10661-019-7289-3
Abstract: Pyrite undergoes oxidation when exposed to aqueous oxygen to produce acidic leachate with high concentrations of H
Publisher: Wiley
Date: 2003
DOI: 10.1002/XRS.668
Publisher: Elsevier BV
Date: 05-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 29-03-2019
Abstract: Rapid spread of disease is a hazard in our interconnected world. The chytrid fungus Batrachochytrium dendrobatidis was identified in hibian populations about 20 years ago and has caused death and species extinction at a global scale. Scheele et al. found that the fungus has caused declines in hibian populations everywhere except at its origin in Asia (see the Perspective by Greenberg and Palen). A majority of species and populations are still experiencing decline, but there is evidence of limited recovery in some species. The analysis also suggests some conditions that predict resilience. Science , this issue p. 1459 see also p. 1386
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 08-2009
Publisher: MDPI AG
Date: 08-09-2022
DOI: 10.3390/MIN12091138
Abstract: This study presented the first in a series of investigations currently underway to develop efficacious, cost-effective, and benign processing opportunities to produce rare earth elements (REE)–rich concentrate from an Australian complex low–grade saprolite ore [1.14% total rare earth oxides (TREO) grade], which is primarily exploited for its gold and copper values. This work specifically presented a preliminary flotation investigation carried out on the ore using sodium oleate as a collector. The relative effects of pulp pH, desliming, and depressants were investigated to ascertain any chance of recovering and upgrading REE minerals in saprolite ore using three different processing configurations. Based on the experimental results, flotation processes carried out on raw feed allowed the recovery of the majority of REE minerals ( %), but the process was unselective, where clay and silicate gangue minerals reported into the flotation concentrate along with the REE minerals. However, desliming before flotation in the presence of depressants (starch and sodium silicate) improved REE minerals flotation selectivity, which produced concentrates assaying 5.87% and 4.22% TREO grades, with corresponding recoveries of 45% and 50% at pulp pH 9 and 10.5, respectively. Mineralogical analysis conducted on selected flotation concentrate indicated that silicate and clay gauge minerals were recovered via the synergistic act of surface activation and entrainment due to their fine to ultrafine nature. A comparison of all the test results revealed a haphazard grade–recovery relationship suggesting that there is an opportunity to further maximize both REE recovery and grade through further flotation studies where other process parameters may be investigated and optimized. The prospect of using magnetic separation has also been suggested.
Publisher: Wiley
Date: 05-05-2010
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.JCIS.2008.01.042
Abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been examined as a possible predictive tool for surface wettability. Heterogeneous surfaces were prepared with hydrophilic and hydrophobic regions of known surface coverage using self-assembled monolayers. The surface coverage of each component was then correlated with ToF-SIMS fragmentation of the hydrophobic and hydrophilic surface groups and static contact angle measurements. From these measurements, a clear relationship between the surface wettability and relative intensity of characteristic secondary ions was identified. Moreover, our results for planar surfaces can be extrapolated to predict the wettability of particulate s les for which direct contact angle measurements are not straightforward. The ability to infer particle wettability by ToF-SIMS is well suited to mineral characterization and in particular, the prediction of mineral flotation efficiencies.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 10-2005
Publisher: Elsevier BV
Date: 12-2012
Publisher: Elsevier BV
Date: 12-2007
Publisher: Informa UK Limited
Date: 21-01-2019
Publisher: Informa UK Limited
Date: 25-03-2009
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 10-2010
Publisher: Informa UK Limited
Date: 06-06-2021
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 02-2015
Publisher: Academy of Science of South Africa
Date: 31-01-2022
DOI: 10.17159/2411-9717/1654/2022
Abstract: Recently, coal fly ash has become a potential candidate as a secondary resource of rare earth elements (REE). In this investigation, we studied the recovery of REE from fly ash from a commercial power plant. The specific aim was to assess the technical feasibility of recovering REE from the coal fly ash using conventional preconcentration methods, including gravity separation, magnetic separation, and froth flotation. The experimental results revealed that flotation achieved major gains in REE recovery and upgrading. However, during gravity and wet magnetic separation tests, the bulk of REE reported to the tailings. The results showed significant variations in the performance of the various beneficiation methods investigated. This study has confirmed that existing physical separation methods could be used to recover REE from coal fly ash prior to hydrometallurgical and pyrometallurgical processing, although some challenges persist.
Publisher: Elsevier BV
Date: 08-2023
Publisher: Elsevier BV
Date: 2010
Publisher: Informa UK Limited
Date: 24-06-2021
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier BV
Date: 03-2016
Publisher: Elsevier BV
Date: 12-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CE00545G
Abstract: Chalcopyrite copper indium disulfide (CIS) QDs have been of recent interest due to their non-toxicity. This article shows a straightforward aqueous cation exchange method to synthesise CIS particles with zinc sulfide coating.
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 11-2006
Publisher: Elsevier BV
Date: 03-2001
Publisher: Elsevier BV
Date: 08-2012
Publisher: Elsevier BV
Date: 06-2019
Publisher: Springer Science and Business Media LLC
Date: 07-11-2020
DOI: 10.1007/S00181-019-01788-0
Abstract: We consider the problem of macroeconomic forecasting for China. Our objective is to determine whether well-established forecasting models that are commonly used to compute forecasts for Western macroeconomies are also useful for China. Our study includes 19 different forecasting models, ranging from simple approaches such as the naive forecast to more sophisticated techniques such as ARMA, Bayesian VAR, and factor models. We use these models to forecast two different measures of price inflation and two different measures of real activity, with forecast horizons ranging from 1 to 12 months, over a period that stretches from March 2005 to December 2018. We test null hypotheses of equal mean squared forecasting error between each candidate model and a simple benchmark. We find evidence that AR, ARMA, VAR, and Bayesian VAR models provide superior 1-month-ahead forecasts of the producer price index when compared to simple benchmarks, but find no evidence of superiority over simple benchmarks at longer horizons, or for any of our other variables.
Publisher: Elsevier BV
Date: 04-2005
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 05-2004
Publisher: Mineralogical Association of Canada
Date: 08-2005
Publisher: Elsevier BV
Date: 03-2015
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.JCIS.2008.02.044
Abstract: The co-sorption reaction products of arsenate (As(V)) and copper (Cu(II)) on goethite (alpha-FeOOH) and natro-jarosite (Na(3)Fe(3)(SO(4))(2)(OH)(6)) were investigated with extended X-ray absorption fine structure (EXAFS) spectroscopy to determine if Cu(II) and As(V) would form precipitates or compete with each other for surface sites. The reaction products were prepared by mixing 250 microM Cu(SO(4)) with 10, 25, or 50 microM Na(2)HAsO(4) at pH 5.65 and allowing the mixture to react in 10 m(2) L(-1) goethite or jarosite suspensions for 12 days. In addition, EXAFS data of Cu(SO(4)) and As(V) sorbed on goethite and jarosite were collected as control species. All reaction conditions were under-saturated with respect to common copper bearing minerals: tenorite (CuO), brochantite (Cu(4)(OH)(6)SO(4)), and hydrated clinoclase (Cu(3)(AsO(4))(2)2H(2)O). The extents of the As(V) and Cu(II) surface adsorption reactions showed a strong competitive effect from Cu(II) on As(V) adsorption for a nominal Cu:As mole-ratio of 25:1. With increasing nominal As(V) concentration, As(V) sorption on goethite and jarosite increased without diminishing the amount of Cu(II) sorption. In the absence of either co-sorbate, As(V) and Cu(II) formed the expected surface adsorption species, i.e., bidentate binuclear and edge-sharing surface complexes, consistent with previously published results. In each other's presence, the local bonding environments of As(V) and Cu(II) showed that the co-sorbates form a precipitate on the goethite and jarosite surface at nominal concentrations of 10:1 and 5:1. At nominal Cu:As mole-ratios of 25:1, Cu(II) did not form significantly different surface complexes on goethite or jarosite from those in the absence of As(V), however, As K-edge EXAFS results distinctly showed Cu(II) atoms in As(V)'s local bonding environment on the goethite surface. The structures of the two precipitates were different and depended on the anion-layer structure and possibly the presence of structural oxyanions in the case of jarosite. On goethite, the copper-arsenate precipitate was similar to hydrated clinoclase, while on jarosite, a euchroite-like precipitate (Cu(2)[AsO(4)](OH)3H(2)O, P 2(1)2(1)2(1)) had formed. Despite under-saturated solution conditions, the formation of these precipitates may have occurred due to a seed-formation effect from densely surface adsorbed Cu(II) and As(V) for which the "new" saturation index was significantly lower than homogeneous values would otherwise suggest. Synergistic reactions between two co-sorbates of fundamentally different surface adsorption behaviour can thus be achieved if the number of available sites for surface adsorption is limited.
Publisher: Elsevier BV
Date: 02-2014
Publisher: Wiley
Date: 04-03-2020
DOI: 10.1002/SIA.6753
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 2001
Publisher: Mineralogical Society of America
Date: 05-2023
DOI: 10.2138/AM-2022-8415
Abstract: Arsenian pyrite is known to have a strong association with gold in most auriferous refractory deposits, and thus understanding the chemical speciation of arsenic in localized environments in arsenian pyrite provides an important basis for determining its reactivity and mobility. However, arsenic is fast-oxidizing among elements in the Fe-As-S system and hence it may exist in various chemical states, which renders it difficult to establish arsenic nature under pristine conditions, particularly in arsenian pyrite. Herein, arsenian pyrite s les were analyzed on a synchrotron soft X-ray spectroscopy beamline under ultrahigh vacuum conditions, and As-3d as well as S-2p spectra were collected. A comparison between the spectrum of bulk As-3d in the s les with its bulk counterpart in arsenopyrite revealed a 0.6 eV shift toward lower binding energies. This observation was similar to loellingite (FeAs2), where the binding energy shift was attributed to high electron density on As of the As-As dimer. Formation of As clusters resulting in comparable binding energy shifts was also proposed from the spectroscopic studies. The experiments were complemented by a series of first-principles calculations simulating four experimentally observed pyrite surfaces where surficial S atoms were randomly substituted by As. As such, six arsenian pyrite crystal surfaces were modeled, two of which constituted surficial As clusters replacing both S and Fe atoms. The surfaces were geometrically optimized, and surface energies were calculated along with the corresponding electronic structure providing a detailed distribution of partial charges for surficial atoms obtained from Löwdin population analysis. The calculated partial charges of atoms located at the surface arsenian pyrite indicated that while the electron density on the As atom of As-S dimers in arsenian pyrite is less negative than the As in bulk arsenopyrite, it is more negative for the As atom of As-As dimers, which were only seen in the surficial As clusters. This validated the description of As presence in arsenian pyrite as local clusters inducing localized lattice strain due to increased bond distances. Our findings offer a good background for future studies into the reactive sites in arsenian pyrite and how that compares with associated minerals, arsenopyrite, and pyrite.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA04041E
Abstract: Synthesis and excellent photocatalytic H 2 evolution performance of diaminotetrazine based highly ordered 3D mesoporous carbon nitrides (MCN-9) with C 3 N 6 stoichiometry prepared by employing KIT-6 silica template has been demonstrated.
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 04-2006
Publisher: Springer Science and Business Media LLC
Date: 04-11-2016
DOI: 10.1007/S11356-015-5654-5
Abstract: Pristine chitosan beads were modified with sulfur (S)-containing functional groups to produce thiolated chitosan beads (ETB), thereby increasing S donor ligands and crosslinks. The effect of temperature, heating time, carbon disulfide (CS2)/chitosan ratio, and pH on total S content of ETB was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The total S content of ETB increased with increasing CS2/chitosan ratio and decreased with decreasing pH and increasing temperature (>60 °C) and heating time (at 60 °C). Spectroscopic analyses revealed the presence of thiol (-SH)/thione, disulfide (-S-S-), and sulfonate groups in ETB. The thiolation mechanism involves decomposition of dithiocarbamate groups, thereby forming thiourea crosslinks and trithiocarbonate, resulting in -SH oxidation to produce -S-S- crosslinks. The partially formed ETB crosslinks contribute to its acid stability and are thermodynamically feasible in adsorbing Cd and Cu. The S-containing functional groups added to chitinous wastes act as sorbents for metal remediation from acidic environments.
Publisher: American Chemical Society (ACS)
Date: 18-04-2006
DOI: 10.1021/ES052158V
Abstract: A variety of techniques (secondary electron microscopy with energy dispersive X-ray analysis, time-of-flight--secondary ion mass spectrometry, and synchrotron X-ray fluorescence) were utilized to distinguish metal contamination occurring in hair arising from endogenous uptake from an in idual exposed to a polluted environment, in this case a lead smelter. Evidence was sought for elements less affected by contamination and potentially indicative of biogenic activity. The unique combination of surface sensitivity, spatial resolution, and detection limits used here has provided new insight regarding hair analysis. Metals such as Ca, Fe, and Pb appeared to have little representative value of endogenous uptake and were mainly due to contamination. Cu and Zn, however, demonstrate behaviors worthy of further investigation into relating hair concentrations to endogenous function.
Publisher: Elsevier BV
Date: 10-2010
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C12B_3
Abstract: We propose a method to significantly reduce speckle originating from the intrinsic coherence of a supercontinuum laser used for reflectance spectroscopy. Rotating the s les and spectral averaging reveals the characteristic spectra of two minerals.
Publisher: Elsevier BV
Date: 06-2015
Publisher: Oxford University Press (OUP)
Date: 02-2007
Abstract: Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) is a highly surface sensitive analytical method for surface chemical identification and surface chemical distribution analysis (mapping). Here we have explored the application of ToF-SIMS for the characterization of solid-state pharmaceuticals and highlight specific case studies concerning the distribution and stability of pharmaceutical actives within solid matrices (pellets and polymeric carriers) and the face-specific properties of pharmaceutical crystals.
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 12-2017
Publisher: International Union of Crystallography (IUCr)
Date: 09-05-2009
Publisher: Elsevier BV
Date: 02-2009
Publisher: SAGE Publications
Date: 12-2003
DOI: 10.1255/EJMS.584
Abstract: Hair from four in iduals excavated from burial sites in Pacatnamu, Peru from the Moche (450–800 AD) and Lambayeque (900–1100 AD) periods was sectioned longitudinally and analysed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). An attempt was made to distinguish biogenic and diagenetic contributions to the elemental concentrations in the hair s les. Significant contamination was observed to have penetrated the hair s les from the burial environment. Results from the analyses indicate that the burial environment plays an important role in the postmortem variation in elemental content of hair s les. Various elements demonstrated an ability to permeate through the hair matrix over time. In addition, NaCl and what are believed to be aluminosilicates and mineral sulphates, were observed to have accumulated on the surface of the s les. Degradation of the s les was also suspected due to the presence of molecular fragments, possibly resulting from oxidation of the keratin proteins. The results should assist in the identification of reliable elemental signals in the analysis of ancient hair s les and promote caution when considering elements that are abundant in the burial environment.
Publisher: Springer Science and Business Media LLC
Date: 10-06-2009
Publisher: MDPI AG
Date: 10-04-2019
DOI: 10.3390/JCS3020041
Abstract: This research extensively investigates how to enhance the mechanical performance of Rubcrete, aiming to move this type of concrete from the laboratory research level to a more practical use by the concrete industry. The effects of many different mixing procedures, chemical pre-treatments on the rubber particles, and the use of fibre additives, have been investigated for their impact upon Rubcrete workability, compressive strength, tensile strength, and flexural strength. The mixing procedure variables included mixing time and mixing order. The rubber pre-treatments utilized chemicals such as Sodium Hydroxide (NaOH), Hydrogen Peroxide (H2O2), Sulphuric acid (H2SO4), Calcium Chloride (CaCl2), Potassium Permanganate (KMnO4), Sodium Bisulphite (NaHsO3), and Silane Coupling Agent. Soaking rubber particles in tap water, or running them through water before mixing, were also tried as a pre-treatment of rubber particles. In addition, the effects of fibre additives such as steel fibres, polypropylene fibres, and rubber fibres, were assessed. X-ray photoelectron spectroscopy (XPS) analysis was utilised to examine some of the pre-treated rubber particles. The results showed that doubling the net mixing time of all mix constituents together enhanced the Rubcrete slump by an average of 22%, and the compressive strength by up to 8%. Mixing rubber with dry cement before adding to the mix increased the compressive strength by up to 3%. Pre-treatment using water was more effective than other chemicals in enhancing the Rubcrete workability. Regardless of the treatment material type, the longer the time of the treatment, the more cleaning of rubber occurred. Significant Rubcrete flexural strength increase occurred when using 1.5% fibre content of both steel fibre and polypropylene fibre.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Springer Science and Business Media LLC
Date: 10-03-2020
Publisher: Elsevier BV
Date: 09-2021
Publisher: MDPI AG
Date: 26-10-2020
DOI: 10.3390/MIN10110955
Abstract: In our previous studies, we demonstrated the performance of novel superfine crusher and pneumatic planar magnetic separator as energy-efficient technologies for dry processing of magnetite ores. The present study investigates the economic and socio-environmental benefits of applying these technologies in conceptual dry magnetite ore processing flowsheet. The outcome of the study is compared with that of a conceptual wet processing flowsheet for the same ore. The cost estimations used are based on the Brook Hunt C1 methodology whilst revenue estimations are based on the Platts Iron Ore Index specification. The demonstrated economic and socio-environmental benefits show that dry processing flowsheet offers significant energy and cost savings and improved revenue generation compared with the wet process flowsheet. These findings are vital to the magnetite industry, particularly in water- and energy-scarce regions as a benchmark for future studies aimed at deepening and expanding the knowledge base of dry beneficiation of magnetite ores.
Publisher: Springer Science and Business Media LLC
Date: 27-05-2012
DOI: 10.1007/S12011-012-9456-Z
Abstract: A major difficulty in hair elemental (mineral) analysis for biomonitoring is adequate understanding of the effectiveness of washing procedures. A review of washing protocols used in hair analysis publications showed little consensus with regard to solvents and surfactants used, washing times, and number of washing stages. Two washing approaches were subsequently used to compare their influence on internal and external surface elemental signals determined with time-of-flight secondary ion mass spectrometry. Na, K, Ca, Mg, and Fe were assessed with regard to their relative signal compared to carbon. Both washing methods had similar effect. All elements except for Fe appear to be removed from the surface of the hair as well as from inside the hair. Only the internal Fe content changed with washing and could indicate that external surface bound Fe may not be removed with most washing procedures. It is shown that washing procedures can have a significant effect on reducing the internal elemental signal levels in hair.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TC03833B
Abstract: Increasing the light harvesting efficiency of photocathodes is an integral part of optimising the future efficiencies of solar technologies.
Publisher: International Union of Crystallography (IUCr)
Date: 03-09-2010
Publisher: Informa UK Limited
Date: 2015
DOI: 10.15834/CIMJ.2015.3
Publisher: Elsevier BV
Date: 12-1995
Publisher: Elsevier BV
Date: 08-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA08029K
Abstract: Nano-thin coatings of glutaraldehyde cross-linked polyethyleneimine effectively and selectively accumulated copper from natural seawater.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for William Skinner.