Razzokov J (2019) Molecular level simulations for plasma medicine applications. 173 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Michielsen I (2019) Plasma catalysis : study of packing materials on CO2 reforming in a DBD reactor. 215 p
Keywords: Doctoral thesis; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Ramakers M (2019) Using a gliding arc plasmatron for CO2 conversion : the future in industry? 235 p
Keywords: Doctoral thesis; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“A spatial approach to identify priority areas for pesticide pollution mitigation”. Quaglia G, Joris I, Broekx S, Desmet N, Koopmans K, Vandaele K, Seuntjens P, Journal of environmental management 246, 583 (2019). http://doi.org/10.1016/J.JENVMAN.2019.04.120
Abstract: Identifying priority areas is an essential step in developing management strategies to reduce pesticide loads in surface water. A spatially explicit model-based approach was developed to detect priority areas for diffuse pesticide pollution at catchment scale. The method uses available datasets and considers different pesticide pathways in the environment post-application. The approach was applied in a catchment area in SE Flanders (Belgium) as a case study. Calculated risk areas were obtained using detailed landscape data and combining pesticide emissions and hydrological connectivity. The risk areas obtained were further compared with an alternative observation-based method, developed specifically for this study site that includes long-term field observations and local expert knowledge. Both methods equally classified 50% of the areas. The impact of crop rotation on the calculated risk was analysed. High-risk areas were identified and added to a cumulative map over all five years to evaluate temporal variations. The model-based approach was used for the initial identification of risk areas at the study site. The tool helps to prioritise zones and detect particular fields to target landscape mitigation measures to reduce diffuse pesticide pollution reaching surface water bodies.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.JENVMAN.2019.04.120
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“Chronic interstitial nephritis in agricultural communities is a toxin induced proximal tubular nephropathy”. Vervaet BA, Nast CC, Jayasumana C, Schreurs G, Roels F, Herath C, Kojc N, Samaee V, Rodrigo S, Gowrishankar S, Mousson C, Dassanayake R, Orantes CM, Vuiblet V, Rigothier C, d' Haese PC, de Broe ME, Kidney international 97, 350 (2019). http://doi.org/10.1016/J.KINT.2019.11.009
Abstract: Almost 30 years after the detection of chronic interstitial nephritis in agricultural communities (CINAC) its etiology remains unknown. To help define this we examined 34 renal biopsies from Sri Lanka, El Salvador, India and France of patients with chronic kidney disease 2-3 and diagnosed with CINAC by light and electron microscopy. In addition to known histopathology, we identified a unique constellation of proximal tubular cell findings including large dysmorphic lysosomes with a light-medium electron-dense matrix containing dispersed dark electron-dense non-membrane bound “aggregates”. These aggregates associated with varying degrees of cellular/tubular atrophy, apparent cell fragment shedding and no-weak proximal tubular cell proliferative capacity. Identical lysosomal lesions, identifiable by electron microscopy, were observed in 9% of renal transplant implantation biopsies, but were more prevalent in six month (50%) and 12 month (67%) protocol biopsies and in indication biopsies (76%) of calcineurin inhibitor treated transplant patients. The phenotype was also found associated with nephrotoxic drugs (lomustine, clomiphene, lithium, cocaine) and in some patients with light chain tubulopathy, all conditions that can be directly or indirectly linked to calcineurin pathway inhibition or modulation. One hundred biopsies of normal kidneys, drug/toxin induced nephropathies, and overt proteinuric patients of different etiologies to some extent could demonstrate the light microscopic proximal tubular cell changes, but rarely the electron microscopic lysosomal features. Rats treated with the calcineurin inhibitor cyclosporine for four weeks developed similar proximal tubular cell lysosomal alterations, which were absent in a dehydration group. Overall, the finding of an identical proximal tubular cell (lysosomal) lesion in CINAC and calcineurin inhibitor nephrotoxicity in different geographic regions suggests a common paradigm where CINAC patients undergo a tubulotoxic mechanism similar to calcineurin inhibitor nephrotoxicity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory Experimental Medicine and Pediatrics (LEMP); Pathophysiology
Impact Factor: 8.395
DOI: 10.1016/J.KINT.2019.11.009
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Cautaerts N (2019) Nanoscale study of ageing and irradiation induced precipitates in the DIN 1.4970 alloy. 306 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Fatermans J (2019) Quantitative atom detection from atomic-resolution transmission electron microscopy images. 155 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Van der Donck M (2019) Excitonic complexes in transition metal dichalcogenides and related materials. 224 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Vieira De Castro L (2019) Properties of quasi particles on two dimensional materials and related structures. 79 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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“Impact of urban street canyon architecture on local atmospheric pollutant levels and magneto-chemical PM10 composition : an experimental study in Antwerp, Belgium”. Hofman J, Castanheiro A, Nuyts G, Joosen S, Spassov S, Blust R, De Wael K, Lenaerts S, Samson R, The science of the total environment 712, 135534 (2019). http://doi.org/10.1016/J.SCITOTENV.2019.135534
Abstract: As real-life experimental data on natural ventilation of atmospheric pollution levels in urban street canyons is still scarce and has proven to be complex, this study, experimentally evaluated the impact of an urban street canyon opening on local atmospheric pollution levels, during a 2-week field campaign in a typical urban street canyon in Antwerp, Belgium. Besides following up on atmospheric particulate matter (PM), ultrafine particles (UFPs) and black carbon (BC) levels, the magneto-chemical PM10 composition was quantified to identify contributions of specific elements in enclosed versus open street canyon sections. Results indicated no higher overall PM, UFP and BC concentrations at the enclosed site compared to the open site, but significant day-to-day variability between both monitoring locations, depending on the experienced wind conditions. On days with oblique wind regimes (4 out of 14), natural ventilation was observed at the open location while higher element contributions of Ca, Fe, Co, Ni, Cu, Zn and Sr were exhibited at the enclosed location. Magnetic properties correlated with the PM10 filter loading, and elemental content of Fe, Cr, Mn and Ti. Magnetic bivariate ratios identified finel-grained magnetite carriers with grain sizes below 0.1 μm, indicating similar magnetic source contributions at both monitoring locations. Our holistic approach, combining atmospheric monitoring with magneto-chemical PM characterization has shown the complex impact of real-life wind flow regimes, different source contributions and local traffic dynamics on the resulting pollutant concentrations and contribute to a better understanding on the urban ventilation processes of atmospheric pollution.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.9
DOI: 10.1016/J.SCITOTENV.2019.135534
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“Coupled plasmon modes in 2D gold nanoparticle clusters and their effect on local temperature control”. Borah R, Verbruggen SW, The journal of physical chemistry: C : nanomaterials and interfaces 123, 30594 (2019). http://doi.org/10.1021/ACS.JPCC.9B09048
Abstract: Assemblies of closely separated gold nanoparticles exhibit a strong collective plasmonic response due to coupling of the plasmon modes of the individual nanostructures. In the context of self-assembly of nanoparticles, close-packed two-dimensional (2D) clusters of spherical nanoparticles present an important composite system that promises numerous applications. The present study probes the collective plasmonic characteristics and resulting photothermal behavior of close-packed 2D Au nanoparticle clusters to delineate the effects of the cluster size, interparticle distance, and particle size. Smaller nanoparticles (20 and 40 nm in diameter) that exhibit low individual scattering and high absorption were considered for their relevance to photothermal applications. In contrast to typical literature studies, the present study compares the optical response of clusters of different sizes ranging from a single nanoparticle up to large assemblies of 61 nanoparticles. Increasing the cluster size induces significant changes to the spectral position and optophysical characteristics. Based on the model outcome, an optimal cluster size for maximum absorption per nanoparticle is also determined for enhanced photothermal effects. The effect of the particle size and interparticle distance is investigated to elucidate the nature of interaction in terms of near-field and far-field coupling. The photothermal effect resulting from absorption is compared for different cluster sizes and interparticle distances considering a homogeneous water medium. A strong dependence of the steady-state temperature of the nanoparticles on the cluster size, particle position in the cluster, incident light polarization, and interparticle distance provides new physical insight into the local temperature control of plasmonic nanostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.536
DOI: 10.1021/ACS.JPCC.9B09048
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“Economic performance of using batteries in European residential microgrids under the net-metering scheme”. Saviuc I, Peremans H, Van Passel S, Milis K, Energies 12, 165 (2019). http://doi.org/10.3390/EN12010165
Abstract: Decentralized energy production offers an increased share of renewable energy and autonomy compared to the conventional, grid-only solution. However, under the net-metering scheme, the energy losses in batteries translate into financial losses to an investor seeking to move away from grid-only electricity and set up a residential PV+Battery microgrid. Our paper examines a hypothetical support scheme for such a project, designed to balance the economic disadvantage through partially supporting the acquisition of batteries, and thus ensure that the microgrid solution is more attractive than no investment. For this we develop four case studies based on experiments carried out in Greece, Italy, Denmark and Finland. Using the minimization of the Net Present Cost for each project, we compare the PV+Battery solution to the grid-only scenario over 25 years, for a range of electricity prices. The results illustrate first how the success of this project depends on the price of electricity. Second, we find that under current conditions in the respective countries the need for battery support varies between zero in Denmark and 86% in Italy, which reflects how the disadvantages of net metering can only be counterbalanced by either very high electricity price or very high solar resource. Our paper contributes thus to the discussion about the favourable environment for batteries in residential microgrids.
Keywords: A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 2.262
DOI: 10.3390/EN12010165
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“Conserving African biosphere reserves : a workshop on the valuation of ecosystem services in Man and the Biosphere Reserves”. Janssens de Bisthoven L, Rochette A-J, Verheyen E, Akpona TJ-D, Verbist B, Vanderhaegen K, Naturinda Z, Van Passel S, Berihun D, Munishi L, Hugé, J, Oryx 53, 609 (2019). http://doi.org/10.1017/S003060531900070X
Keywords: A1 Journal article; Engineering Management (ENM); Evolutionary ecology group (EVECO)
Impact Factor: 2.191
DOI: 10.1017/S003060531900070X
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Yao X (2019) An advanced TEM study on quantification of Ni4Ti3 precipitates in low temperature aged Ni-Ti shape memory alloy. 149 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Trenchev G (2019) Computational modelling of atmospheric DC discharges for CO2 conversion. 206 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Van der Paal J (2019) Generation, transport and molecular interactions of reactive species in plasma medicine. 237 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Lumbeeck G (2019) Mechanisms of nano-plasticity in as-deposited and hydrided nanocrystalline Pd and Ni thin films. 130 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Anđ,elković, M (2019) O(N) numerical methods for investigating graphene heterostructures and moiré patterns. 207 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Chuon S (2019) Simulation numérique multi-échelles du procédé de dépôt par pulvérisation cathodique magnétron. 137 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Guzzinati G, Ghielens W, Mahr C, Bé,ché, A, Rosenauer A, Calders T, Verbeeck J (2019) Electron Bessel beam diffraction patterns, line scan of Si/SiGe multilayer
Keywords: Dataset; ADReM Data Lab (ADReM); Electron microscopy for materials research (EMAT)
DOI: 10.5281/ZENODO.2566137
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“On the nucleation mechanism of {112} <, 111 >, mechanical twins in as-quenched beta metastable Ti-12 wt.% Mo alloy”. Marteleur M, Idrissi H, Amin-Ahmadi B, Prima F, Schryvers D, Jacques PJ, Materialia 7, Unsp 100418 (2019). http://doi.org/10.1016/J.MTLA.2019.100418
Abstract: Recently developed beta-metastable Ti grades take advantage of the simultaneous activation of TRIP and TWIP effects for enhancing their work hardening rate. However, the role of each plasticity mechanism on the macroscopic mechanical response is still unclear. In this work, the nucleation mechanism of the first activated plasticity mechanism, namely {112} < 111 > twinning, was investigated. Firstly, post-mortem TEM analysis showed that twins nucleate on pre-existing microstructural defects such as thermal jogs with the zonal dislocation mechanism. The precipitation of the omega phase on twin boundaries has been observed, as well as the emission of numerous dislocations from super-jogs present in these twin boundaries. It is also shown that {112} < 111 > twins act as effective dislocation sources for the subsequent plasticity mechanisms such as beta -> alpha '' martensitic transformation and {332} < 111 > twinning. Secondly, in situ TEM tensile testing of the investigated Ti grade highlighted the primary role of the initial defect configuration present in the microstructure. It is shown that twins cannot nucleate without the presence of specific defects allowing the triggering of the dislocation decomposition needed for the twinning mechanism highlighted in investigated bulk samples.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1016/J.MTLA.2019.100418
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Guzzinati G, Bé,ché, A, McGrouther D, Verbeeck J (2019) Rotation of electron beams in the presence of localised, longitudinal magnetic fields
Abstract: Electron Bessel beams have been generated by inserting an annular aperture in the illumination system of a TEM. These beams have passed through a localised magnetic field. As a result a low amount of image rotation (which is expected to be proportional to the longitudinal component of the magnetic field) is observed in the far field. A measure of this rotation should give access to the magneti field. The two datasets have been acquired in a FEI Titan3 microscope, operated at 300kV. The file focalseries.tif contains a series of images acquired varying the magnetic field through the objective lens. The file lineprofile.ser contains a series of images acquired by scanning the beam over a sample with several magnetised nanopillars. For reference, check the associated publication.
Keywords: Dataset; Electron microscopy for materials research (EMAT)
DOI: 10.5281/ZENODO.3232898
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Jannis D, Mü,ller-Caspary K, Bé,ché, A, Oelsner A, Verbeeck J (2019) Spectrocopic coincidence experiment in transmission electron microscopy
Abstract: This dataset contains individual EEL and EDX events where for every event (electron or X-ray), their energy and time of arrival is stored. The experiment was performed in a transmission electron microscope (Tecnai Osiris) at 200 keV. The material investigated is an Al-Mg-Si-Cu alloy. The 'full_dataset.mat' contains the full dataset and the 'subset.mat' has the first five frames of the full dataset. The attached 'EELS-EDX.ipynb' is a jupyter notebook file. This file describes the data processing in order to observe the temporal correlation between the electrons and X-rays.
Keywords: Dataset; Electron microscopy for materials research (EMAT)
DOI: 10.5281/ZENODO.2563880
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Idrissi H, Samaee V, Lumbeeck G, van der Werf T, Pardoen T, Schryvers D, Cordier P (2019) Supporting data for “In situ Quantitative Tensile Tests on Antigorite in a Transmission Electron Microscope”
Abstract: The determination of the mechanical properties of serpentinites is essential towards the understanding of the mechanics of faulting and subduction. Here, we present the first in situ tensile tests on antigorite in a transmission electron microscope. A push-to-pull deformation device is used to perform quantitative tensile tests, during which force and displacement are measured, while the microstructure is imaged with the microscope. The experiments have been performed at room temperature on beams prepared by focused ion beam. The specimens are not single crystals despite their small sizes. Orientation mapping indicated that some grains were well-oriented for plastic slip. However, no dislocation activity has been observed even though engineering tensile stress went up to 700 MPa. We show also that antigorite does not exhibit an pure elastic-brittle behaviour since, despite the presence of defects, the specimens underwent plastic deformation and did not fail within the elastic regime. Instead, we observe that strain localizes at grain boundaries. All observations concur to show that under our experimental conditions, grain boundary sliding is the dominant deformation mechanism. This study sheds a new light on the mechanical properties of antigorite and calls for further studies on the structure and properties of grain boundaries in antigorite and more generally in phyllosilicates.
Keywords: Dataset; Electron microscopy for materials research (EMAT)
DOI: 10.5281/ZENODO.3583135
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“3D Eulerian-Eulerian modeling of a screw reactor for biomass thermochemical conversion. Part 1: solids flow dynamics and back-mixing”. Shi X, Ronsse F, Roegiers J, Pieters JG, Renewable energy 143, 1465 (2019). http://doi.org/10.1016/J.RENENE.2019.05.098
Abstract: Three-dimensional (3D) computational fluid dynamics (CFD) simulations were performed to study solids flow dynamics and solids back-mixing behavior in a screw reactor (designed for thermal conversion of dry biomass particles) based on the Eulerian-Eulerian method. Simulation results were compared against experimental data with respect to filling degree and mean residence time of particles. The mean deviations for filling degree and for mean residence time between simulation and experiment were about 0.01 and 11.4 s, respectively, which shows that the model is reasonably accurate in predicting solids flow behavior in the screw reactor. The solids flow dynamics inside the reactor were discussed. The solids residence time distribution (RTD) was calculated and the degree of solids back-mixing in the forward transportation direction of the reactor was analyzed. It was found that solids being flung over the shaft and solids back-leakage, resulting from the low solids forward transportation velocity at the clearance between the flight and the bottom shell of the screw reactor, were responsible for solids back-mixing. The degree of solids back-mixing can be reduced at higher screw rotating speeds when keeping inlet mass flow rate of solids constant. (C) 2019 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.RENENE.2019.05.098
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“Achieving Fast Kinetics and Enhanced Li Storage Capacity for Ti3C2O2 by Intercalation of Quinone Molecules”. Siriwardane EMD, Demiroglu I, Sevik C, Cakir D, ACS applied energy materials 2, 1251 (2019). http://doi.org/10.1021/ACSAEM.8B01801
Abstract: Using first-principles calculations, we demonstrated that high lithium storage capacity and fast kinetics are achieved for Ti3C2O2 by preintercalating organic molecules. As a proof-of-concept, two different quinone molecules, namely 1,4-benzoquinone (C6H4O2) and tetrafluoro-1,4-benzoquinone (C6F4O2) were selected as the molecular linkers to demonstrate the feasibility of this interlayer engineering strategy for energy storage. As compared to Ti3C2O2 bilayer without linker molecules, our pillared structures facilitate a much faster ion transport, promising a higher charge/discharge rate for Li. For example, while the diffusion barrier of a single Li ion within pristine Ti3C2O2 bilayer is at least 1.0 eV, it becomes 0.3 eV in pillared structures, which is comparable and even lower than that of commercial materials. At high Li concentrations, the calculated diffusion barriers are as low as 0.4 eV. Out-of-plane migration of Li ions is hindered due to large barrier energy with a value of around 1-1.35 eV. Concerning storage capacity, we can only intercalate one monolayer of Li within pristine Ti3C2O2 bilayer. In contrast, pillared structures offer significantly higher storage capacity. Our calculations showed that at least two layers of Li can be intercalated between Ti3C2O2 layers without forming bulk Li and losing the pillared structure upon Li loading/unloading. A small change in the in-plane lattice parameters (<0.5%) and volume (<1.0%) and ab initio molecular dynamics simulations prove the stability of the pillared structures against Li intercalation and thermal effects. Intercalated molecules avoid the large contraction/expansion of the whole structure, which is one of the key problems in electrochemical energy storage. Pillared structures allow us to realize electrodes with high capacity and fast kinetics. Our results open new research paths for improving the performance of not only MXenes but also other layered materials for supercapacitor and battery applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1021/ACSAEM.8B01801
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“Aerodynamic characterisation of green wall vegetation based on plant morphology : an experimental and computational fluid dynamics approach”. Koch K, Samson R, Denys S, Biosystems engineering 178, 34 (2019). http://doi.org/10.1016/J.BIOSYSTEMSENG.2018.10.019
Abstract: The installation of urban green infrastructure, particularly green walls, has proven to be an effective strategy for the mitigation of particulate matter (PM) pollution and the urban heat island effect. For the interaction between vegetation, PM and the local microclimate, wind flow is the main driving force. In order to investigate these interactions in detail, it is important to know how air flows through vegetation. This study proposes a method based on the DarcyForchheimer equation, where vegetation is considered as a porous medium and several plant species and the effects of plant morphological characteristics are examined both experimentally and using computer simulations. Results showed that the DarcyForchheimer model is a simple and robust way to describe air flow through vegetation regardless of its morphology. This research provides a new vision on studying aerodynamic properties of vegetation in relation to their morphology and provides opportunities for model the interaction between vegetation and its environment.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIOSYSTEMSENG.2018.10.019
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“Azimuthal and radial flow patterns of 1g-Geldart B-type particles in a gas-solid vortex reactor”. Gonzalez-Quiroga A, Kulkarni SR, Vandewalle L, Perreault P, Goel C, Heynderickx GJ, van Geem KM, Marin GB, Powder technology 354, 410 (2019). http://doi.org/10.1016/J.POWTEC.2019.06.015
Abstract: Processes requiring intensive interfacial momentum, mass and heat exchange between gases and particulate solids can be greatly enhanced by operating in a centrifugal field. This is realized in the Gas-Solid Vortex Reactor (GSVR) with centrifugal accelerations up to two orders of magnitude higher than the Earth's gravitational acceleration. Here, the flow patterns of two 1g-Geldart B-type particles are experimentally assessed, over the gas inlet velocity range 82–126 m s−1, in an 80 mm diameter and 15 mm height GSVR. The particles are monosized aluminum spheres of 0.5 mm diameter, and walnut shell in the sieve fraction 0.50–0.56 mm and aspect ratio 1.3 ± 0.2. Two dimensional Particle Image Velocimetry combined with Digital Image Analysis and pressure measurements revealed that periodic fluctuations in solids azimuthal and radial velocity between gas inlet slots are strongly related to the average solids azimuthal velocity and bed uniformity. Aluminum particles feature steeper changes in azimuthal velocity and more attenuated changes in radial velocity than walnut shell particles. Within the assessed gas inlet velocity range the solids bed of aluminum exhibits average azimuthal velocities and bed voidages 40–50% and ≈10% lower than those of walnut shell. The aerodynamic response time of the particles, i.e. ρsdp2/18μg, emerged as an important parameter to assess the influence of the carrier gas jet on the radial deflection of the particles and the interaction solids bed-outer wall. Too low aerodynamic response time relates to nonuniformity in bed voidage due to solids radial velocity fluctuations. Excessive aerodynamic response time indicates low solids azimuthal velocities due to solids bed-outer wall friction.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.POWTEC.2019.06.015
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“Ballistic thermoelectric properties of monolayer semiconducting transition metal dichalcogenides and oxides”. Ozbal G, Senger RT, Sevik C, Sevincli H, Physical review B 100, 085415 (2019). http://doi.org/10.1103/PHYSREVB.100.085415
Abstract: Combining first-principles calculations with Landauer-Mittiker formalism, ballistic thermoelectric transport properties of semiconducting two-dimensional transition metal dichalcogenides (TMDs) and oxides (TMOs) (namely MX2 with M = Cr, Mo, W, Ti, Zr, Hf; X = O, S, Se, Te) are investigated in their 2H and 1T phases. Having computed structural, as well as ballistic electronic and phononic transport properties for all structures, we report the thermoelectric properties of the semiconducting ones. We find that 2H phases of four of the studied structures have very promising thermoelectric properties, unlike their 1T phases. The maximum room temperature p-type thermoelectric figure of merit (ZT) of 1.57 is obtained for 2H-HfSe2, which can be as high as 3.30 at T = 800 K. Additionally, 2H-ZrSe2, 2H-ZrTe2, and 2H-HfS2 have considerable ZT values (both nand p-type), that are above 1 at room temperature. The 1T phases of Zr and Hf-based oxides possess relatively high power factors, however their high lattice thermal conductance values limit their ZT values to below 1 at room temperature.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1103/PHYSREVB.100.085415
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“Beauty is skin deep : the skin tones of Vermeer's Girl with a Pearl Earring”. van Loon A, Vandivere A, Delaney JK, Dooley KA, De Meyer S, Vanmeert F, Gonzalez V, Janssens K, Leonhardt E, Haswell R, de Groot S, D'Imporzano P, Davies GR, Heritage science 7, 102 (2019). http://doi.org/10.1186/S40494-019-0344-0
Abstract: The soft modelling of the skin tones in Vermeer's Girl with a Pearl Earring (Mauritshuis) has been remarked upon by art historians, and is their main argument to date this painting to c. 1665. This paper describes the materials and techniques Vermeer used to accomplish the smooth flesh tones and facial features of the Girl, which were investigated as part of the 2018 Girl in the Spotlight research project. It combines macroscopic X-ray fluorescence imaging (MA-XRF), reflectance imaging spectroscopy (RIS), and 3D digital microscopy. Vermeer built up the face, beginning with distinct areas of light and dark. He then smoothly blended the final layers to create almost seamless transitions. The combination of advanced imaging techniques highlighted that Vermeer built the soft contour around her face by leaving a 'gap' between the background and the skin. It also revealed details that were otherwise not visible with the naked eye, such as the eyelashes. Macroscopic imaging was complemented by the study of paint cross-sections using: light microscopy, SEM-EDX, FIB-STEM, synchrotron radiation mu-XRPD and FTIR-ATR. Vermeer intentionally used different qualities or grades of lead white in the flesh paints, showing different hydrocerussite/cerussite ratios and particle sizes. Lead isotope analysis showed that the geographic source of lead, from which the different types of lead white were manufactured, was the same: the region of Peak District of Derbyshire, UK. Finally, cross-section analysis identified the formation of new lead species in the paints: lead soaps and palmierite (K2Pb(SO4)(2)), associated with the red lake.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1186/S40494-019-0344-0
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