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“Assessing the stability of arsenic sulfide pigments and influence of the binding media on their degradation by means of spectroscopic and electrochemical techniques”. Vermeulen M, Janssens K, Sanyova J, Rahemi V, McGlinchey C, De Wael K, Microchemical journal 138, 82 (2018). http://doi.org/10.1016/J.MICROC.2018.01.004
Abstract: In this paper, we used the semiconducting and lightfastness properties of synthetic and mineral arsenic sulfide pigments to study their stability by means of electrochemical and microfadometric techniques. A combination of these techniques shows that in the early stage of the degradation process, amorphous arsenic sulfides are more stable than both crystalline forms, while upon longer exposure time, amorphous pigments will fade more than both mineral pigments, making it less suitable. While the stability study was carried out on unbound pigments, the influence of the organic binder on the relative degradation of the arsenic sulfide pigments was investigated through a multi-analytical approach on pigment/binder mock-up paint samples. For this purpose, the formation of arsenic trioxide was assessed by micro Fourier transform infrared (μ-FTIR) spectroscopy while the influence of the binder on the formation of sulfates was studied by means of synchrotron radiation X-ray near edge structure (μ-XANES). Both techniques elucidate a higher stability of all pigments in gum arabic while the use of egg yolk as binder leads to the most degradation, most likely due to its sulfur-rich composition. In the context of the degradation of arsenic sulfide pigments, other binders such as animal glue, egg white or linseed oil show an intermediate impact.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.034
Times cited: 4
DOI: 10.1016/J.MICROC.2018.01.004
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“Applications of synchrotron X-ray nano-probes in the field of cultural heritage”. Cotte M, Genty-Vincent A, Janssens K, Susini J, Comptes rendus : physique 19, 575 (2018). http://doi.org/10.1016/J.CRHY.2018.07.002
Abstract: Synchrotron-based techniques are increasingly used in the field of cultural heritage, and this review focuses notably on the application of nano-beams to access high-spatial-resolution information on fragments sampled in historical or model artworks. Depending on the targeted information, various nano-analytical techniques can be applied, providing both identification and localization of the various components. More precisely, nano-X-ray fluorescence probes elements, nano-X-ray diffraction identify crystalline phases, and nano X-ray absorption spectroscopy is sensitive to speciation. Furthermore, computed tomography-based techniques can provide useful information about the morphology and in particular the porosity of materials. (C) 2018 Academie des sciences. Published by Elsevier Masson SAS.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.048
Times cited: 3
DOI: 10.1016/J.CRHY.2018.07.002
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“Application of Gielis transformation to the design of metamaterial structures”. de Jong van Coevorden CM, Gielis J, Caratelli D, Journal of physics : conference series 963, Unsp 012008 (2018). http://doi.org/10.1088/1742-6596/963/1/012008
Abstract: In this communication, the use of Gielis transformation to design more compact metamaterial unit cells is explored. For this purpose, transformed complementary split ring resonators and spiral resonators are coupled to micro-strip lines and theirbehaviour is investigated. The obtained results confirm that the useof the considered class of supershaped geometries enables the synthesis of very compact scalable microwave components.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1088/1742-6596/963/1/012008
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“Anomalous behavior of the electronic structure of (Bi1-xInx)2Se3across the quantum phase transition from topological to trivial insulator”. Sanchez-Barriga J, Aguilera I, Yashina L V, Tsukanova DY, Freyse F, Chaika AN, Callaert C, Abakumov AM, Hadermann J, Varykhalov A, Rienks EDL, Bihlmayer G, Blugel S, Rader O, Physical review B 98, 235110 (2018). http://doi.org/10.1103/PHYSREVB.98.235110
Abstract: Using spin- and angle-resolved photoemission spectroscopy and relativistic many-body calculations, we investigate the evolution of the electronic structure of (Bi1-xInx)(2)Se-3)(2)Se-3 bulk single crystals around the critical point of the trivial to topological insulator quantum-phase transition. By increasing x, we observe how a surface gap opens at the Dirac point of the initially gapless topological surface state of Bi2Se3, leading to the existence of massive fermions. The surface gap monotonically increases for a wide range of x values across the topological and trivial sides of the quantum-phase transition. By means of photon-energy-dependent measurements, we demonstrate that the gapped surface state survives the inversion of the bulk bands which occurs at a critical point near x = 0.055. The surface state exhibits a nonzero in-plane spin polarization which decays exponentially with increasing x, and which persists in both the topological and trivial insulator phases. Our calculations reveal qualitative agreement with the experimental results all across the quantum-phase transition upon the systematic variation of the spin-orbit coupling strength. A non-time-reversal symmetry-breaking mechanism of bulk-mediated scattering processes that increase with decreasing spin-orbit coupling strength is proposed as explanation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1103/PHYSREVB.98.235110
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“Anisotropic charge density wave in electron-hole double monolayers : applied to phosphorene”. Saberi-Pouya S, Zarenia M, Vazifehshenas T, Peeters FM, Physical review B 98, 245115 (2018). http://doi.org/10.1103/PHYSREVB.98.245115
Abstract: The possibility of an inhomogeneous charge density wave phase is investigated in a system of two coupled electron and hole monolayers separated by a hexagonal boron nitride insulating layer. The charge-density-wave state is induced through the assumption of negative compressibility of electron/hole gases in a Coulomb drag configuration between the electron and hole sheets. Under equilibrium conditions, we derive analytical expressions for the density oscillation along the zigzag and armchair directions. We find that the density modulation not only depends on the sign of the compressibility but also on the anisotropy of the low-energy bands. Our results are applicable to any two-dimensional system with anisotropic parabolic bands, characterized by different effective masses. For equal effective masses, i.e., isotropic energy bands, our results agree with Hroblak et al. [Phys. Rev. B 96, 075422 (2017)]. Our numerical results are applied to phosphorene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
DOI: 10.1103/PHYSREVB.98.245115
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“Anisotropic bulk and planar Heisenberg ferromagnets in uniform, arbitrarily oriented magnetic fields”. Vanherck J, Sorée B, Magnus W, Journal of physics : condensed matter 30, 275801 (2018). http://doi.org/10.1088/1361-648X/AAC65F
Abstract: Today, further downscaling of mobile electronic devices poses serious problems, such as energy consumption and local heat dissipation. In this context, spin wave majority gates made of very thin ferromagnetic films may offer a viable alternative. However, similar downscaling of magnetic thin films eventually enforces the latter to operate as quasi-2D magnets, the magnetic properties of which are not yet fully understood, especially those related to anisotropies and external magnetic fields in arbitrary directions. To this end, we have investigated the behaviour of an easy-plane and easy-axis anisotropic ferromagnet-both in two and three dimensions-subjected to a uniform magnetic field, applied along an arbitrary direction. In this paper, a spin-1/2 Heisenberg Hamiltonian with anisotropic exchange interactions is solved using double-time temperature-dependent Green's functions and the Tyablikov decoupling approximation. We determine various magnetic properties such as the Curie temperature and the magnetization as a function of temperature and the applied magnetic field, discussing the impact of the system's dimensionality and the type of anisotropy. The magnetic reorientation transition taking place in anisotropic Heisenberg ferromagnets is studied in detail. Importantly, spontaneous magnetization is found to be absent for easy-plane 2D spin systems with short range interactions.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
DOI: 10.1088/1361-648X/AAC65F
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“Analysis of Short-Lived Reactive Species in Plasma–Air–Water Systems: The Dos and the Do Nots”. Gorbanev Y, Privat-Maldonado A, Bogaerts A, Analytical Chemistry 90, 13151 (2018). http://doi.org/10.1021/acs.analchem.8b03336
Abstract: This Feature addresses the analysis of the reactive species generated by nonthermal atmospheric
pressure plasmas, which are widely employed in industrial and biomedical research, as well as first
clinical applications. We summarize the progress in detection of plasma-generated short-lived
reactive oxygen and nitrogen species in aqueous solutions, discuss the potential and limitations of
various analytical methods in plasma−liquid systems, and provide an outlook on the possible future
research goals in development of short-lived reactive species analysis methods for a general
nonspecialist audience.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 6.32
Times cited: 17
DOI: 10.1021/acs.analchem.8b03336
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“Ammonia Synthesis by Radio Frequency Plasma Catalysis: Revealing the Underlying Mechanisms”. Shah J, Wang W, Bogaerts A, Carreon ML, ACS applied energy materials 1, 4824 (2018). http://doi.org/10.1021/acsaem.8b00898
Abstract: Nonthermal plasma is a promising alternative for ammonia synthesis at gentle conditions. Metal meshes of Fe, Cu, Pd, Ag, and Au were employed as catalysts in radio frequency plasma for ammonia synthesis. The energy yield for all these transition metal catalysts ranged between 0.12 and 0.19 g-NH3/kWh at 300 W and, thus, needs further improvement. In addition, a semimetal, pure gallium, was used for the first time as catalyst for ammonia synthesis, with energy yield of 0.22 g-NH3/kWh and with a maximum yield of ∼10% at 150 W. The emission spectra, as well as computer simulations, revealed hydrogen recombination as a primary governing parameter, which depends on the concentration or flux of H atoms in the plasma and on the catalyst surface. The simulations helped to elucidate the underlying mechanism, implicating the dominance of surface reactions and surface adsorbed species. The rate limiting step appears to be NH2 formation on the surface of the reactor wall and on the catalyst surface, which is different from classical catalysis.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1021/acsaem.8b00898
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“Alternative Metals: from ab initio Screening to Calibrated Narrow Line Models”. Adelmann C, Sankaran K, Dutta S, Gupta A, Kundu S, Jamieson G, Moors K, Pinna N, Ciofi I, Van Elshocht S, Bommels J, Boccardi G, Wilson CJ, Pourtois G, Tokei Z, Proceedings of the IEEE ... International Interconnect Technology Conference
T2 –, IEEE International Interconnect Technology Conference (IITC), JUN 04-07, 2018, Santa Clara, CA , 154 (2018). http://doi.org/10.1109/IITC.2018.8456484
Abstract: We discuss the selection and assessment of alternative metals by a combination of ab initio computation of electronic properties, experimental resistivity assessments, and calibrated line resistance models. Pt-group metals as well as Nb are identified as the most promising elements, with Ru showing the best combination of material properties and process maturity. An experimental assessment of the resistivity of Ru, Ir, and Co lines down to similar to 30 nm(2) is then used to devise compact models for line and via resistance that can be compared to Cu predictions. The main advantage of alternative metals originates from the possibility for barrierless metallization.
Keywords: P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1109/IITC.2018.8456484
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“Agricultural land conversion : reviewing drought impacts and coping strategies”. Azadi H, Keramati P, Taheri F, Rafiaani P, Teklemariam D, Gebrehiwot K, Hosseininia G, Van Passel S, Lebailly P, Witlox F, International Journal Of Disaster Risk Reduction 31, 184 (2018). http://doi.org/10.1016/J.IJDRR.2018.05.003
Abstract: This paper aims to review the impacts of drought on agricultural land conversion (ALC) on the one hand and the impacts of ALC on intensifying drought on the other. The paper further investigates coping strategies at three levels; i.e., micro (local), meso (national), and macro (international), in order to mitigate drought impacts that are classified as economic, social, and environmental. This paper shows that ALC, drought and coping strategies are in a reciprocal relationship and can have either a positive or negative influence on each other. The paper concludes that the complex and multidimensional nature of drought requires the development of an integrated approach that focuses on the governments collaboration with different stakeholders. Such an integrated approach can improve drought risk management implementations, decrease vulnerability and construct resilience and coping capacity at all levels in order to deal with droughts.
Keywords: A1 Journal article; Economics; Engineering Management (ENM); Government and Law
Impact Factor: 1.603
Times cited: 7
DOI: 10.1016/J.IJDRR.2018.05.003
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“Advanced first-principles theory of superconductivity including both lattice vibrations and spin fluctuations : the case of FeB4”. Bekaert J, Aperis A, Partoens B, Oppeneer PM, Milošević, MV, Physical review B 97, 014503 (2018). http://doi.org/10.1103/PHYSREVB.97.014503
Abstract: <script type='text/javascript'>document.write(unpmarked('We present an advanced method to study spin fluctuations in superconductors quantitatively and entirely from first principles. This method can be generally applied to materials where electron-phonon coupling and spin fluctuations coexist. We employ it here to examine the recently synthesized superconductor iron tetraboride (FeB4) with experimental T-c similar to 2.4 K [H. Gou et al., Phys. Rev. Lett, 111, 157002 (2013)]. We prove that FeB4 is particularly prone to ferromagnetic spin fluctuations due to the presence of iron, resulting in a large Stoner interaction strength, I = 1.5 eV, as calculated from first principles. The other important factor is its Fermi surface that consists of three separate sheets, among which two are nested ellipsoids. The resulting susceptibility has a ferromagnetic peak around q = 0, from which we calculated the repulsive interaction between Cooper pair electrons using the random phase approximation. Subsequently, we combined the electron-phonon interaction calculated from first principles with the spin fluctuation interaction in fully anisotropic Eliashberg theory calculations. We show that the resulting superconducting gap spectrum is conventional, yet very strongly depleted due to coupling to the spin fluctuations. The critical temperature decreases from T-c = 41 K, if they are not taken into account, to T-c = 1.7 K, in good agreement with the experimental value.'));
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 23
DOI: 10.1103/PHYSREVB.97.014503
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Winckelmans N (2018) Advanced electron tomography to investigate the growth of homogeneous and heterogeneous nanoparticles. Antwerpen
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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“Access to preferential loans for poverty reduction and rural development : evidence from Vietnam”. Lan Thanh Nguyen, Anh Pham Hoai Nguyen, Van Passel S, Azadi H, Lebailly P, Journal Of Economic Issues 52, 246 (2018). http://doi.org/10.1080/00213624.2018.1430953
Abstract: Preferential loans play an important role in the process of reducing poverty in developing countries. Considering the data set from the 2010 Vietnam Household Living Standards Survey, we aim to examine the influential factors in probability of households getting access to preferential loans. Additionally, we analyze the determinants of household income in association with the loans by applying a quantile regression model. Our results show that ethnicity-related factors have the largest marginal effect on the access to preferential loans. The results from the quantile regression model demonstrate that the debt factor has a deeper impact on the borrowing group at the lower quantiles of household income.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
Impact Factor: 0.581
Times cited: 3
DOI: 10.1080/00213624.2018.1430953
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Bekaert J (2018) Ab initio description of multicomponent superconductivity in bulk to atomically thin materials. Antwerpen
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Bekaert J (2018) Ab initio description of multicomponent superconductivity in bulk to atomically thin materials. 290 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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“Ab initio and semiempirical modeling of excitons and trions in monolayer TiS3”. Torun E, Sahin H, Chaves A, Wirtz L, Peeters FM, Physical review B 98, 075419 (2018). http://doi.org/10.1103/PHYSREVB.98.075419
Abstract: We explore the electronic and the optical properties of monolayer TiS3, which shows in-plane anisotropy and is composed of a chain-like structure along one of the lattice directions. Together with its robust direct band gap, which changes very slightly with stacking order and with the thickness of the sample, the anisotropic physical properties of TiS3 make the material very attractive for various device applications. In this study, we present a detailed investigation on the effect of the crystal anisotropy on the excitons and the trions of the TiS3 monolayer. We use many-body perturbation theory to calculate the absorption spectrum of anisotropic TiS3 monolayer by solving the Bethe-Salpeter equation. In parallel, we implement and use a Wannier-Mott model for the excitons that takes into account the anisotropic effective masses and Coulomb screening, which are obtained from ab initio calculations. This model is then extended for the investigation of trion states of monolayer TiS3. Our calculations indicate that the absorption spectrum of monolayer TiS3 drastically depends on the polarization of the incoming light, which excites different excitons with distinct binding energies. In addition, the binding energies of positively and the negatively charged trions are observed to be distinct and they exhibit an anisotropic probability density distribution.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PHYSREVB.98.075419
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Asapu R (2018) A study of plasmonic systems using Layer-by-Layer synthesized core-shell nanoparticles. 142 p
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
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“A stochastic techno-economic assessment of seabed mining of polymetallic nodules in the Clarion Clipperton Fracture Zone”. Van Nijen K, Van Passel S, Squires D, Marine Policy 95, 133 (2018). http://doi.org/10.1016/J.MARPOL.2018.02.027
Abstract: Polymetallic nodules found in the Clarion Clipperton Fracture Zone in the NE Pacific contain more nickel, manganese and cobalt than all terrestrial reserves combined. Following the 1982 Law of the Sea Convention and its 1994 Implementing Agreement, the resources of the international seabed beyond the limits of national jurisdiction will be developed for the benefit of mankind by attracting investment and technology, whilst demanding that necessary measures be taken to ensure effective protection of the marine environment. To date, no single commercial seabed mining activity has taken place in international waters, and the development of balanced and stimulating exploitation regulation is needed, based on accurate economic analysis. This paper presents the first detailed, vertically integrated, stochastic techno-economic assessment from a contractor's perspective, and contributes to the development of the world's first exploitation regulations. The economic performance measured by the internal rate of return was compared using deterministic and probabilistic commodity price forecasting models. Different levels of a financial payment regime, comprising of a royalty payment and a payment to internalize environmental costs, were considered. When real growth was included, the internal rate of return remains above the hurdle rate when a transitional, total-cost, financial payment regime is below 2 per cent during the initial period and below 4 per cent for the remaining tenure period. Following a 10-year moving average of commodity prices, including real growth, a 77.51 per cent probability was calculated of achieving a hurdle rate of 18 per cent.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
Impact Factor: 2.235
Times cited: 3
DOI: 10.1016/J.MARPOL.2018.02.027
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“A simplified protocol for usage of new immuno-SERS probes for detection of casein, collagens and ovalbumin in cross-sections of artworks”. Hrdlickova Kuckova S, Hamidi-Asl E, Sofer Z, Marvan P, De Wael K, Sanyova J, Janssens K, Analytical methods 10, 1054 (2018). http://doi.org/10.1039/C7AY01864A
Abstract: Although it is now relatively straightforward to identify protein binders in works of art, their proper localization within the corresponding layer still represents a significant analytical challenge. Until now, the identification of proteins has mainly been performed by peptide mass fingerprinting using mass spectrometric methods and their localization in polished paint cross-sections have been realized by optical microscopy via the use of fluorescent stain Sypro Ruby (SR). In this work we propose a simplified protocol for immuno-surface enhanced Raman scattering (immuno-SERS) using gold nanoparticles attached to biphenyl-4,4-dithiol (BPDT) as the SERS-nanotag. These nanoparticles are easily obtainable in the lab and have been used to label multilayered mock up samples prepared as cross-sections to estimate the detection limits of the suggested method. The layers contain egg, casein, and different animal glues binders (prepared in various ratios with linseed oil or a carbohydrate component) mixed with the pigments azurite, vermilion and chalk. The sensitivity of staining agent SR is compared to that of the immuno-SERS protocol for the first time.
Keywords: A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.9
Times cited: 3
DOI: 10.1039/C7AY01864A
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“A Roman Egyptian Painting Workshop : technical investigation of the portraits from Tebtunis, Egypt”. Salvant J, Williams J, Ganio M, Casadio F, Daher C, Sutherland K, Monico L, Vanmeert F, De Meyer S, Janssens K, Cartwright C, Walton M, Archaeometry 60, 815 (2018). http://doi.org/10.1111/ARCM.12351
Abstract: Roman-period mummy portraits are considered to be ancient antecedents of modern portraiture. However, the techniques and materials used in their manufacture are not thoroughly understood. Analytical study of the pigments as well as the binding materials helps to address questions on what aspects of the painting practices originate from Pharaonic and/or Graeco-Roman traditions, and can aid in determining the provenance of the raw materials from potential locations across the ancient Mediterranean and European worlds. Here, one of the largest assemblages of mummy portraits to remain intact since their excavation from the site of Tebtunis in Egypt was examined using multiple analytical techniques to address how they were made. The archaeological evidence suggests that these portraits were products of a single workshop and, correspondingly, they are found to be made using similar techniques and materials: wax-based and lead white-rich paint combined with a variety of iron-based pigments (including hematite, goethite and jarosite), as well as Egyptian blue, minium, indigo and madder lake to create subtle variations and tones.
Keywords: A1 Journal article; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.47
Times cited: 6
DOI: 10.1111/ARCM.12351
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“A review of sustainability indicators for biobased chemicals”. Van Schoubroeck S, Van Dael M, Van Passel S, Malina R, Renewable &, Sustainable Energy Reviews 94, 115 (2018). http://doi.org/10.1016/J.RSER.2018.06.007
Abstract: Companies dealing with chemical products have to cope with large amounts of waste and environmental risk due to the use and production of toxic substances. Against this background, increasing attention is being paid to green chemistry and the translation of this concept into biobased chemicals. Given the multitude of economic, environmental and societal impacts that the production and use of biobased chemicals have on sustainability, assessment approaches need to be developed that allow for measurement and comparison of these impacts. To evaluate sustainability in the context of policy and decision-making, indicators are generally accepted means. However, sustainability indicators currently predominantly exist for low-value applications in the bioeconomy, like bioenergy and biofuels. In this paper, a review of the state-of-the-art sustainability indicators for biobased chemicals is conducted and a gap analysis is performed to identify indicator development needs. Based on the analysis, a clear hierarchy within the concept of sustainability is found where the environmental aspect dominates over economic and social indicators. All one-dimensional indicator-sets account for environmental impacts (50%), whereas two-dimensional sets complement the environmental issues with economic indicators (34%). Moreover, even the sets encompassing all three sustainability dimensions (16%) do not account for the dynamics and interlinkages between the environment, economy and society. Using results from the literature review, an indicator list is presented that captures all indicators currently used within sustainability assessment of biobased chemicals. Finally, a framework is proposed for future indicator selection using a stakeholder survey to obtain a prioritized list of sustainability indicators for biobased chemicals.
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 8.05
Times cited: 17
DOI: 10.1016/J.RSER.2018.06.007
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“A packed-bed DBD micro plasma reactor for CO 2 dissociation: Does size matter?”.Uytdenhouwen Y, Van Alphen S, Michielsen I, Meynen V, Cool P, Bogaerts A, Chemical engineering journal 348, 557 (2018). http://doi.org/10.1016/j.cej.2018.04.210
Abstract: DBD plasma reactors are of great interest for environmental and energy applications, such as CO2 conversion, but they suffer from limited conversion and especially energy efficiency. The introduction of packing materials has been a popular subject of investigation in order to increase the reactor performance. Reducing the discharge gap of the reactor below one millimetre can enhance the plasma performance as well. In this work, we combine both effects and use a packed-bed DBD micro plasma reactor to investigate the influence of gap size reduction, in combination with a packing material, on the conversion and efficiency of CO2 dissociation. Packing materials used in this work were SiO2, ZrO2, and Al2O3 spheres as well as glass wool. The results are compared to a regular size reactor as a benchmark. Reducing the discharge gap can greatly increase the CO2 conversion, although at a lower energy efficiency. Adding a packing material further increases the conversion when keeping a constant residence time, but is greatly dependent on the material composition, gap and sphere size used. Maximum conversions of 50–55% are obtained for very long residence times (30 s and higher) in an empty reactor or with certain packing material combinations, suggesting a balance in CO2 dissociation and recombination reactions. The maximum energy efficiency achieved is 4.3%, but this is for the regular sized reactor at a short residence time (7.5 s). Electrical characterization is performed to reveal some trends in the electrical behaviour of the plasma upon reduction of the discharge gap and addition of a packing material.
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.216
Times cited: 22
DOI: 10.1016/j.cej.2018.04.210
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“A new opportunity for biomagnetic monitoring of particulate pollution in an urban environment using tree branches”. Wuyts K, Hofman J, van Wittenberghe S, Nuyts G, De Wael K, Samson R, Atmospheric environment : an international journal 190, 177 (2018). http://doi.org/10.1016/J.ATMOSENV.2018.07.014
Abstract: Environmental magnetism, and the magnetic leaf signal in particular, is amply investigated and applied as proxy for atmospheric particulate matter pollution. In this study, we investigated the magnetic signal of annual segments of tree branches, and the composition of particles deposited hereon. Branches are, contrary to leaves of deciduous trees, available during leaf-off seasons and exposed to air pollution year-round. We examined the intra- and inter-tree variation in saturation isothermal remanent magnetization (SIRM) of branch internodes of London plane (Platanus x aeerifolia Willd.) trees in an urban environment. The branch SIRM, normalized by surface area, ranged from 18 to 650 x 10(-6) angstrom; the median amounted to 106 x 10(-6) angstrom. Most of the branch magnetic signal was attributed to the epidermis or bark, and the presence of metal-containing particles on the branch surfaces was confirmed by SEM-EDX. The location of the trees and the height, the depth in the crown and the age of the branches significantly influenced the branch SIRM. The median branch SIRM was up to 135% higher near a busy ring road than in quiet environments (city park and quiet street canyon), and was linked to the presence of Fe-rich particles with co-occurrence of trace metals such as Cr, Cu, Zn and Mn on the branch surface. Within the tree crowns, the branch SIRM generally decreased with increasing height, and was 22% higher in the interior than at the periphery of the crowns. Within the branches, the SIRM increased with each year of exposure, but did not relate to year-to-year variation in particle concentrations due to branch surface changes (epidermis shedding). Our results provide indications that branches can be a valuable alternative for biomagnetic monitoring of particulate pollution, but intra-tree variability in branch SIRM can be substantial due to the branch's location in the tree and branch age.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.629
Times cited: 3
DOI: 10.1016/J.ATMOSENV.2018.07.014
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“A Hotelling model for the circular economy including recycling, substitution and waste accumulation”. Hoogmartens R, Eyckmans J, Van Passel S, Resources Conservation And Recycling 128, 98 (2018). http://doi.org/10.1016/J.RESCONREC.2017.09.015
Abstract: Non-renewable resources include a large variety of deposits that have been formed by geological processes over millions of years. Although extraction of such resources provides benefits as employment and economic revenues, it also contributes to negative environmental externalities and it increases resource scarcity. An important policy question is how to optimally extract non-renewable resource stocks over time while taking possible substitutes and recycling into account. The present paper adds to the literature by developing a generic numerical optimisation model that can be used to simulate non-renewable resource management regimes and the effects of different policy instruments deployed at different stages of the resource's life cycle. By including recycling and substitution, the model extends the seminal cake-eating Hotelling model that dominates the non-renewable resource economics literature. In addition to being generically designed, the model can accommodate for non-competitive market settings, interacting policy instruments and environmental externalities at different stages of the material's life cycle. The model's possibilities are illustrated by means of a numerical simulation example for the extraction of sand.
Keywords: A1 Journal article; Engineering Management (ENM)
Impact Factor: 3.313
Times cited: 5
DOI: 10.1016/J.RESCONREC.2017.09.015
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“A general leaf area geometric formula exists for plants evidence from the simplified Gielis equation”. Shi P, Ratkowsky DA, Li Y, Zhang L, Lin S, Gielis J, Forests (19994907) 9, 714 (2018). http://doi.org/10.3390/F9110714
Abstract: Plant leaves exhibit diverse shapes that enable them to utilize a light resource maximally. If there were a general parametric model that could be used to calculate leaf area for different leaf shapes, it would help to elucidate the adaptive evolutional link among plants with the same or similar leaf shapes. We propose a simplified version of the original Gielis equation (SGE), which was developed to describe a variety of object shapes ranging from a droplet to an arbitrary polygon. We used this equation to fit the leaf profiles of 53 species (among which, 48 bamboo plants, 5 woody plants, and 10 geographical populations of a woody plant), totaling 3310 leaves. A third parameter (namely, the floating ratio c in leaf length) was introduced to account for the case when the theoretical leaf length deviates from the observed leaf length. For most datasets, the estimates of c were greater than zero but less than 10%, indicating that the leaf length predicted by the SGE was usually smaller than the actual length. However, the predicted leaf areas approximated their actual values after considering the floating ratios in leaf length. For most datasets, the mean percent errors of leaf areas were lower than 6%, except for a pooled dataset with 42 bamboo species. For the elliptical, lanceolate, linear, obovate, and ovate shapes, although the SGE did not fit the leaf edge perfectly, after adjusting the parameter c, there were small deviations of the predicted leaf areas from the actual values. This illustrates that leaves with different shapes might have similar functional features for photosynthesis, since the leaf areas can be described by the same equation. The anisotropy expressed as a difference in leaf shape for some plants might be an adaptive response to enable them to adapt to different habitats.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.3390/F9110714
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“A distinct correlation between the vibrational and thermal transport properties of group VA monolayer crystals”. Kocabas T, Cakir D, Gulseren O, Ay F, Perkgoz NK, Sevik C, Nanoscale 10, 7803 (2018). http://doi.org/10.1039/C7NR09349G
Abstract: The investigation of thermal transport properties of novel two-dimensional materials is crucially important in order to assess their potential to be used in future technological applications, such as thermoelectric power generation. In this respect, the lattice thermal transport properties of the monolayer structures of group VA elements (P, As, Sb, Bi, PAs, PSb, PBi, AsSb, AsBi, SbBi, P3As1, P3Sb1, P1As3, and As3Sb1) with a black phosphorus like puckered structure were systematically investigated by first-principles calculations and an iterative solution of the phonon Boltzmann transport equation. Phosphorene was found to have the highest lattice thermal conductivity, , due to its low average atomic mass and strong interatomic bonding character. As a matter of course, anisotropic was obtained for all the considered materials, owing to anisotropy in frequency values and phonon group velocities calculated for these structures. However, the determined linear correlation between the anisotropy in the values of P, As, and Sb is significant. The results corresponding to the studied compound structures clearly point out that thermal (electronic) conductivity of pristine monolayers might be suppressed (improved) by alloying them with the same group elements. For instance, the room temperature of PBi along the armchair direction was predicted to be as low as 1.5 W m(-1) K-1, whereas that of P was predicted to be 21 W m(-1) K-1. In spite of the apparent differences in structural and vibrational properties, we peculiarly revealed an intriguing correlation between the values of all the considered materials as = c(1) + c(2)/m(2), in particular along the zigzag direction. Furthermore, our calculations on compound structures clearly showed that the thermoelectric potential of these materials can be improved by suppressing their thermal properties. The presence of ultra-low values and high electrical conductivity (especially along the armchair direction) makes this class of monolayers promising candidates for thermoelectric applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1039/C7NR09349G
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“A comparison of floating-electrode DBD and kINPen jet : plasma parameters to achieve similar growth reduction in colon cancer cells under standardized conditions”. Bekeschus S, Lin A, Fridman A, Wende K, Weltmann K-D, Miller V, Plasma chemistry and plasma processing 38, 1 (2018). http://doi.org/10.1007/S11090-017-9845-3
Abstract: A comparative study of two plasma sources (floating-electrode dielectric barrier discharge, DBD, Drexel University; atmospheric pressure argon plasma jet, kINPen, INP Greifswald) on cancer cell toxicity was performed. Cell culture protocols, cytotoxicity assays, and procedures for assessment of hydrogen peroxide (H2O2) were standardized between both labs. The inhibitory concentration 50 (IC50) and its corresponding H2O2 deposition was determined for both devices. For the DBD, IC50 and H2O2 generation were largely dependent on the total energy input but not pulsing frequency, treatment time, or total number of cells. DBD cytotoxicity could not be replicated by addition of H2O2 alone and was inhibited by larger amounts of liquid present during the treatment. Jet plasma toxicity depended on peroxide generation as well as total cell number and amount of liquid. Thus, the amount of liquid present during plasma treatment in vitro is key in attenuating short-lived species or other physical effects from plasmas. These in vitro results suggest a role of liquids in or on tissues during plasma treatment in a clinical setting. Additionally, we provide a platform for correlation between different plasma sources for a predefined cellular response.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.355
Times cited: 12
DOI: 10.1007/S11090-017-9845-3
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“A comparative DFT study on CO oxidation reaction over Si-doped BC2N nanosheet and nanotube”. Nematollahi P, Neyts EC, Applied surface science 439, 934 (2018). http://doi.org/10.1016/J.APSUSC.2017.12.254
Abstract: In this study, we performed density functional theory (DFT) calculations to investigate different reaction mechanisms of CO oxidation catalyzed by the Si atom embedded defective BC2N nanostructures as well as the analysis of the structural and electronic properties. The structures of all the complexes are optimized and characterized by frequency calculations at the M062X/6-31G* computational level. Also, The electronic structures and thermodynamic parameters of adsorbed CO and O-2 molecules over Si-doped BC2N nanostructures are examined in detail. Moreover, to investigate the curvature effect on the CO oxidation reaction, all the adsorption and CO oxidation reactions on a finite-sized armchair (6,6) Si-BC2NNT are also studied. Our results indicate that there can be two possible pathways for the CO oxidation with O-2 molecule: O-2(g) + CO(g) -> O-2(ads) + CO(ads) -> CO2(g) + O-(ads) and O-(ads) + CO(g) -> CO2(g). The first reaction proceeds via the Langmuir-Hinshelwood (LH) mechanism while the second goes through the Eley-Rideal (ER) mechanism. On the other hand, by increasing the tube diameter, the energy barrier increases due to the strong adsorption energy of the O-2 molecule which is related to its dissociation over the tube surface. Our calculations indicate that the two step energy barrier of the oxidation reaction over Si-BC2NNS is less than that over the Si-BC2NNT. Hence, Si-BC2NNS may serve as an efficient and highly activated substrate to CO oxidation rather than (4,4) Si-BC2NNT. (C) 2018 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.387
Times cited: 8
DOI: 10.1016/J.APSUSC.2017.12.254
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“A Chemical Approach to Raise Cell Voltage and Suppress Phase Transition in O3 Sodium Layered Oxide Electrodes”. Sathiya M, Jacquet Q, Doublet ML, Karakulina OM, Hadermann J, Tarascon J-M, Advanced energy materials (2018). http://doi.org/10.1002/aenm.201702599
Abstract: Sodium ion batteries (NIBs) are one of the versatile technologies for lowcost rechargeable batteries. O3-type layered sodium transition metal oxides (NaMO2, M = transition metal ions) are one of the most promising positive electrode materials considering their capacity. However, the use of O3 phases is limited due to their low redox voltage and associated multiple phase transitions which are detrimental for long cycling. Herein, a simple strategy is proposed to successfully combat these issues. It consists of the introduction of a larger, nontransition metal ion Sn4+ in NaMO2 to prepare a series of NaNi0.5Mn0.5−y SnyO2 (y = 0–0.5) compositions with attractive electrochemical performances, namely for y = 0.5, which shows a single-phase transition from O3 ⇔ P3 at the very end of the oxidation process. Na-ion NaNi0.5Sn0.5O2/C coin cells are shown to deliver an average cell voltage of 3.1 V with an excellent capacity retention as compared to an average stepwise voltage of ≈2.8 V and limited capacity retention for the pure NaNi0.5Mn0.5O2 phase. This study potentially shows the way to manipulate the O3 NaMO2 for facilitating their practical use in NIBs.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 21.875
Times cited: 28
DOI: 10.1002/aenm.201702599
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“3D characterization of heat-induced morphological changes of Au nanostars by fast in situ electron tomography”. Vanrompay H, Bladt E, Albrecht W, Béché, A, Zakhozheva M, Sánchez-Iglesias A, Liz-Marzán LM, Bals S, Nanoscale 10, 22792 (2018). http://doi.org/10.1039/C8NR08376B
Abstract: A thorough understanding of the thermal stability and potential reshaping of anisotropic gold nanostars is required for various potential applications. Combination of a tomographic heating holder with fast tilt series acquisition has been used to monitor temperature-induced morphological changes of Au nanostars. The outcome of our 3D investigations can be used as an input for boundary element method simulations, enabling us to investigate the influence of reshaping on the nanostars’ plasmonic properties. Our work leads to a better understanding of the mechanism behind thermal reshaping. In addition, the approach presented here is generic and can hence be applied to a wide variety of nanoparticles made of different materials and with arbitrary morphology.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 55
DOI: 10.1039/C8NR08376B
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