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“The “oblique&rdquo, zone imaging of the superlattice in complex crystal structure”. Milat O, Krekels T, Van Tendeloo G, Amelinckx S, Icem 13, 859 (1994)
Keywords: A3 Journal article; Electron microscopy for materials research (EMAT)
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“Structural considerations on LanTin-\deltaO3n”. Weill F, Fompeyrine J, Darriet B, Darriet J, Bontchev R, Amelinckx S, Van Tendeloo G, Icem 13, 903 (1994)
Keywords: A3 Journal article; Electron microscopy for materials research (EMAT)
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“Study of quasi-fractal many-particle-systems and percolation networks by zero-loss spectroscopic imaging, electron energy-loss spectroscopy and digital image analysis”. Oleshko V, Kindratenko V, Gijbels R, van Espen P, Jacob W, Mikrochimica acta: supplementum 13, 443 (1996)
Abstract: Submicron colloidal Ag particles and nano-sized filaments forming a statistical percolation network during ''in situ'' development of double structure tabular microcrystals of AgRr(I) emulsions have been studied by electron energy-loss spectroscopy and zero-loss electron spectroscopic imaging (EELS/ZLESI). Image analysis has shown that random quasi-fractal clusters were formed in the colloid. ZLESI has been applied to characterise the morphology and defect structure of aggregated particles and filaments. Their energy-loss spectra revealed plasmon excitations and interband 4d electron transitions between 4-32 eV energy-loss. To study the cluster structure and its relation to the physical properties, fractal analysis including estimations of cluster fractal dimensions and of density autocorrelation functions has been performed. Mechanisms of fractal aggregation based on known models of diffusion limited aggregation, cluster-cluster aggregation and percolation are discussed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Chemometrics (Mitac 3)
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“Stabilization of the perovskite phase in the Y-Bi-O system by using a BaBiO₃, buffer layer”. Bouwmeester RL, de Hond K, Gauquelin N, Verbeeck J, Koster G, Brinkman A, Physica status solidi: rapid research letters 13, 1800679 (2019). http://doi.org/10.1002/PSSR.201800679
Abstract: A topological insulating phase has theoretically been predicted for the thermodynamically unstable perovskite phase of YBiO3. Here, it is shown that the crystal structure of the Y-Bi-O system can be controlled by using a BaBiO3 buffer layer. The BaBiO3 film overcomes the large lattice mismatch of 12% with the SrTiO3 substrate by forming a rocksalt structure in between the two perovskite structures. Depositing an YBiO3 film directly on a SrTiO3 substrate gives a fluorite structure. However, when the Y-Bi-O system is deposited on top of the buffer layer with the correct crystal phase and comparable lattice constant, a single oriented perovskite structure with the expected lattice constants is observed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 11
DOI: 10.1002/PSSR.201800679
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“How do western European farms behave and respond to climate change? A simultaneous irrigation-crop decision model”. Vanschoenwinkel J, Vancauteren M, Van Passel S, Climate change economics 13, 2250009 (2022). http://doi.org/10.1142/S2010007822500099
Abstract: Most farm adaptations are reactive actions that run the risk of locking farm systems into suboptimal long-term trajectories. This is especially the case with regard to water management as water scarcity will be aggravated by climate change. This paper looks into farm irrigation choices in combination with crop choices because a proper crop choice has the potential to reduce water requirements. It proposes an extended Ricardian model to capture multiple adaptation decisions explicitly. The new simultaneous irrigation-crop farm decision model uses spatially detailed farm-level data of over 18,000 European farms on irrigation and seven different crop choices. The analysis shows that larger farmers and farmers in less water-scarce regions that use irrigation are more sensitive to temperature increases than rain-fed agriculture. This might be explained by the fact that these farmers do not experience the real cost of water scarcity because of which they take less efficient decisions.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
DOI: 10.1142/S2010007822500099
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“Enzyme immobilization on/in polymeric membranes : status, challenges and perspectives in biocatalytic membrane reactors (BMRs)”. Jochems P, Satyawali Y, Diels L, Dejonghe W, Green chemistry : cutting-edge research for a greener sustainable future 13, 1609 (2011). http://doi.org/10.1039/C1GC15178A
Abstract: Immobilization of enzymes is beneficial in terms of improving the process economics by enabling enzyme re-use and enhancing overall productivity and robustness. Increasingly, membranes are thought to be good supports for enzyme immobilization. These resulting biocatalytic membranes are integrated in reactors known as biocatalytic membrane reactors (BMRs) which enable the integration of biocatalysis and separation. Often the available commercial membranes require modifications to make them suitable for enzyme immobilization. Different immobilization techniques can be used on such suitable membranes, but no general rules exist for making a choice between them. Despite the advantages of BMR application, there are some issues which need to be addressed in order to achieve up-scaling of such systems. In this review, the different aspects of enzyme immobilization on membranes are discussed to show the complexity of this interdisciplinary technology. In addition, the existing issues which require further investigation are highlighted.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1039/C1GC15178A
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“Geometry errors in 14 MeV neutron activation analysis”. Van Grieken R, Speecke A, Hoste J, Journal of radioanalytical chemistry 13, 225 (1973). http://doi.org/10.1007/BF02514126
Abstract: The effects of inaccurate sample sizes and sample positioning on 14 MeV neutron activation analysis results are estimated for 30, 20 and 10 mm diameter targets. It appears that axial positioning is the most critical parameter and that using a larger tritium target will yield an overall improvement of the reproducibility.
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/BF02514126
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“Heterogeneity effects in direct X-ray fluorescence analysis of hair”. Török S, Van Dyck P, Van Grieken R, X-ray spectrometry 13, 27 (1984). http://doi.org/10.1002/XRS.1300130106
Abstract: The methodology of direct hair analysis by energy-dispersive x-ray fluorescence was studied. The effect on the XRF result of having a non-homogeneous radial distribution of the analyte in a single hair strand and the macroscopic effects in a bundle of hairs were calculated to evaluate possible systematic errors. The detection limits were mapped as a function of the target thickness and surface fraction. It appeared that a 10 mg cm−2 sample thickness, i. e. a target with about four layers of hair strands, is recommended. The standard deviation of this simple direct analytical method is 619% for some important elements. Discrepancies with neutron activation analysis had a mean value of around 15%. About twelve elements can be determined simultaneously on a routine basis.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300130106
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“Kinetics of iron(II) oxidation in seawater of various pH”. Roekens EJ, Van Grieken RE, Marine chemistry 13, 195 (1983). http://doi.org/10.1016/0304-4203(83)90014-2
Abstract: The rate of iron(II) oxidation in North Sea water of pH 5.510 in the range 1025°C has been studied. The oxygenation rate depends linearly on the iron(II) and dissolved oxygen concentrations. The second-order dependence on [OH−], found by several investigators for synthetic solutions, was confirmed in seawater, but only for pOH > 6.9. For pOH < 5.9 the rate appeared to be independent of the pOH. In the intermediate range, pOH 5.96.9, corresponding to the natural pH of seawater, a first-order dependence on the pOH is obeyed. The important discrepancy in the literature between the second-order rate constant for NaCHO3 solutions and for seawater can be attributed predominantly to the incorrect assumption of a second-order pOH dependence in natural seawater. The results can be useful, for example, in predicting the effect of dumping acidic iron waste from the titanium-dioxide industry into the ocean.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0304-4203(83)90014-2
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“Long-Term Stability Control of CVD-Grown Monolayer MoS2”. Sar H, Ozden A, Demiroglu I, Sevik C, Perkgoz NK, Ay F, Physica status solidi: rapid research letters 13, 1800687 (2019). http://doi.org/10.1002/PSSR.201800687
Abstract: The structural stability of 2D transition metal dichalcogenide (TMD) formations is of particular importance for their reliable device performance in nano-electronics and opto-electronics. Recent observations show that the CVD-grown TMD monolayers are likely to encounter stability problems such as cracking or fracturing when they are kept under ambient conditions. Here, two different growth configurations are investigated and a favorable growth geometry is proposed, which also sheds light onto the growth mechanism and provides a solution for the stability and fracture formation issues for TMDs specifically for MoS2 monolayers. It is shown that 18 months naturally and thermally aged MoS2 monolayer flakes grown using specifically developed conditions, retain their stability. To understand the mechanism of the structural deterioration, two possible effective mechanisms, S vacancy defects and growth-induced tensile stress, are assessed by the first principle calculations where the role of S vacancy defects in obtaining oxidation resistant MoS2 monolayer flakes is revealed to be rather more critical. Hence, these simulations, time-dependent observations and thermal aging experiments show that durability and stability of 2D MoS2 flakes can be controlled by CVD growth configuration.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1002/PSSR.201800687
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“Mineral dust variability in central West Antarctica associated with ozone depletion”. Cataldo M, Evangelista H, Simões JC, Godoi RHM, Simmonds I, Hollanda MH, Wainer I, Aquino F, Van Grieken R, Atmospheric chemistry and physics 13, 2165 (2013). http://doi.org/10.5194/ACP-13-2165-2013
Abstract: We present here data of mineral dust variability retrieved from an ice core of the central West Antarctic, spanning the last five decades. Main evidence provided by the geochemical analysis is that northerly air mass incursions to the coring site, tracked by insoluble dust microparticles, have declined over the past 50 yr. This result contrasts with dust records from ice cores reported to the coastal West Antarctic that show increases since mid-20th century. We attribute this difference to regional climatic changes due to the ozone depletion and its implications to westerly winds. We found that the diameters of insoluble microparticles in the central West Antarctica ice core are significantly correlated with cyclone depth (energy) and wind intensity around Antarctica.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/ACP-13-2165-2013
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“Use of laser microprobe mass analysis (LAMMA) for localizing multiple elements in soft and hard tissues”. Verbueken AH, van de Vijver FL, Visser WJ, Roels F, Van Grieken R, de Broe ME, Biological trace element research 13, 397 (1987). http://doi.org/10.1007/BF02796651
Abstract: The potential of laser microprobe mass analysis (LAMMA) as a sensitive microanalytical technique was explored in applications relevant to nephrology. Aluminum and associated elements, such as iron, were localized in fresh tissue biopsies obtained from uremic patients treatment by chronic hemodialysis. The LAMMA was applied to serum, liver, bone, and parathyroid glands of such patients. In addition, we used LAMMA to evaluate the specificity and sensitivity of routine histochemistry, in particular on human bone sections stained by the aluminon method. The high, multielemental sensitivity and molecular microprobe potential of LAMMA established important advantages over other microchemical methods forin situ analysis at the micron level in histological sections.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
DOI: 10.1007/BF02796651
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“Atomistic model of the anisotropic response of ortho-Mo₂C to indentation”. Espinosa IMP, Karaaslan Y, Sevik C, Martini A, AIP advances 13, 065125 (2023). http://doi.org/10.1063/5.0150030
Abstract: Molybdenum carbide has various applications for which studying the material using classical molecular dynamics simulations would be valuable. Here, we develop an empirical potential within the Tersoff formalism using particle swarm optimization for the orthorhombic phase of Mo2C. The developed potential is shown to predict lattice constants, elastic properties, and equation of state results that are consistent with current and previously reported results from experiments and first principles calculations. We demonstrate the potential with simulations of indentation using multiple indenter sizes that load and unload in three different directions relative to the crystallographic lattice of orthorhombic Mo2C. Direction-dependent force-displacement trends are analyzed and explained in terms of the spatial distributions of stress and strain within the material during indentation. This study reveals the anisotropic elasticity of orthorhombic Mo2C and, more generally, provides researchers with a new empirical potential that can be used to explore the properties and behavior of the material going forward.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1063/5.0150030
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“Generalized Möbius-Listing bodies and the heart”. Gielis J, Tavkhelidze I, Ricci PE, Sn –, 2247-689x 13, 58 (2023)
Abstract: Generalized Möbius-Listing surfaces and bodies generalize Möbius bands, and this research was motivated originally by solutions of boundary value problems. Analogous to cutting of the original Möbius band, for this class of surfaces and bodies, results have been obtained when cutting such bodies or surfaces. The results can be applied in a wide range of fields in the natural science, and here we propose how they can serve as a model for the heart and the circulatory system.
Keywords: A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
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“Does contract length matter? The impact of various contract-farming regimes on land-improvement investment and the efficiency of contract farmers in Pakistan”. Mazhar R, Azadi H, Van Passel S, Varnik R, Pietrzykowski M, Skominas R, Wei Z, Xuehao B, Agriculture (Basel) 13, 1651 (2023). http://doi.org/10.3390/AGRICULTURE13091651
Abstract: Land-tenure security is integral to local communities' socioeconomic development. It has been a center of debate in academia and for legislators and advocates to implement reforms to enhance efficient and sustainable development in land management. Yet, knowledge gaps remain in how various contract-farming regimes contribute to land-improvement investment and technical efficiency. This study used a data set of 650 farm households collected through a two-stage stratified sampling to investigate the influence of three contract-farming regimes: long-term, medium-term, and short-term contracts, on the land-improvement investment, productivity, and technical efficiency of contract farmers in Punjab, Pakistan. The study used multivariate probit and ordinary least square regression models to examine the posit relationships. The findings highlight that farmers with long-term land contracts have higher per hectare yield, income and profit than those with medium-term and short-term contracts. The results confirm that farmers with medium- and long-term contracts tend to invest more in land-improvement measures, i.e., organic and green manure. Further, the study findings demonstrate that long-term land tenures are more effective when farmers make decisions regarding the on-farm infrastructure, like tube-well installation, tractor ownership, and holding farm logistics. Last, the study results confirm that long-term contracts are more robust regarding technical efficiency. Moreover, the findings support the Marshallian inefficiency hypothesis and extend the literature on contract farming, land-improvement investment, and land use policy, and offer coherent policy actions for stakeholders to improve farmers' productivity, technical efficiency, and income.
Keywords: A1 Journal article; Engineering Management (ENM)
DOI: 10.3390/AGRICULTURE13091651
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“Oppervlakte en in-diepte analyse via SIMS, SNMS en GDMS”. Gijbels R, Physicalia magazine 14, 49 (1992)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Analyses of petrified wood by electron, X-ray and optical microprobes”. Kuczumov A, Vekemans B, Schalm O, Dorriné, W, Chevallier P, Dillmann P, Ro C-U, Janssens K, Van Grieken R, Journal of analytical atomic spectroscopy 14, 435 (1999). http://doi.org/10.1039/A806748A
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/A806748A
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“Characterization of 18th century Portuguese glass from Real Fábrica de Vidros de Coina”. Lopes F, Lima A, Pires de Matos A, Custódio J, Cagno S, Schalm O, Janssens K, Journal of Archaeological Science: Reports 14, 137 (2017). http://doi.org/10.1016/J.JASREP.2017.05.020
Abstract: This work reports the first systematic chemical characterization of Portuguese 18th century glassware. 28 selected glass fragments, recovered from an archaeological excavation carried out in the site where King D. João V of Portugal established an important glass manufacture, Real Fábrica de Vidros de Coina (Coina Royal Glass Factory), were studied. This factory operated from 1719 until 1747, the year in which the factory was transferred to Marinha Grande. The fragments were analysed by micro-energy dispersive X-ray fluorescence (micro-EDXRF), using a portable spectrometer ArtTAX, and scanning electron microscopy (SEM-EDX). The analytical data showed that a large variety of glass types was manufactured in that factory, namely soda-lime glass, mixed-alkali glass, high lime-low alkali glass, potash glass and lead glass. In general, the composition of the glass varies according to the function of the objects. It was demonstrated that micro-EDXRF can be an important tool to characterize museum glass objects when only in situ non-invasive analytical methods are allowed.
Keywords: A1 Journal article; Engineering sciences. Technology; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Times cited: 3
DOI: 10.1016/J.JASREP.2017.05.020
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“Compositional distinctions between 16th century “Façon-de-Venise&rdquo, and Venetian glass vessels, excavated in Antwerp, Belgium”. Deraedt I, Janssens K, Veeckman J, Journal of analytical atomic spectroscopy 14, 483 (1999). http://doi.org/10.1039/A808385A
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/A808385A
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“Special issue on Microscopic and ultratrace x-ray fluorescence analysis: 2”. Janssens K, Journal of trace and microprobe techniques 14, 461 (1996)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Special issue: Proceedings of the 15th International Congress on X-ray Optics and Microanalysis”. Janssens K, Journal of analytical atomic spectroscopy 14, 357 (1999)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“A covalently linked dyad based on zinc phthalocyanine and methylpheophorbide &alpha, : synthetic and physicochemical study”. Balashova IO, Tolbin AY, Tarakanov PA, Krot AR, Fedorova K V, Sergeeva IA, Trashin SA, De Wael K, Pushkarev VE, Koifman MO, Ponomarev G V, Macroheterocycles 14, 40 (2021). http://doi.org/10.6060/MHC210338P
Abstract: The first covalently linked conjugate of metal phthalocyaninate and chlorin e(6) derivative has been obtained by transesterification of alpha-ketomethyl ester in methylpheophorbide a with zinc(II) 2-(2-hydroxymethylbenzyloxy)-9(10),16(17),23(24)-tri-tert-butylphthalocyaninate under mild conditions. The dyad exhibits a panchromatic nature revealing both the phthalocyanine and pheophorbide derived bands in the UV-Vis absorption spectrum. The H-1 NMR spectroscopy data combined with theoretical calculations indicate the presence of spatial intramolecular interactions between the phthalocyanine, pheophorbide and spacer fragments of the dyad allowing to forecast its enhanced nonlinear optical properties, as well as the characteristic energy transfer from the excited pheophorbide subunit to the phthalocyanine core. Indeed, when excited in the UV-Vis range, the conjugate shows red fluorescence with the spectral maximum at 686 nm, which is close to the one of the initial zinc phthalocyaninate. Furthermore, the dyad effectively generates singlet oxygen and, in the presence of polyvinylpyrrolidone (PVP) as biocompatible solubilizer, forms stable micellar saline solutions with the particles ranged in size between 40 and 100 nm. These nanoparticles represent promising third-generation photosensitizing systems for application in theranostics.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.6060/MHC210338P
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“Conservation of stained glass windows with protective glazing : main results from the European VIDRIO research programme”. Bernardi A, Becherini F, Verità, M, Godoi RHM, Kontozova-Deutsch V, Van Grieken R, et al, Journal of cultural heritage 14, 527 (2013). http://doi.org/10.1016/J.CULHER.2012.11.009
Abstract: The methodology of protecting the European stained glass windows against environmental risk (e.g. meteorological factors, air pollution, microorganisms) by means of an external glazing is not new. In spite of many scientific studies carried out in the last 20 years, some questions were still up for discussion. The European VIDRIO (20022005) project gave an answer to these questions. The research carried out by the different project partners established a new multidisciplinary approach aimed at evaluating the efficiency of the protective glazing systems and their effects on stained glass windows conservation, and finally at assessing the most appropriate strategy to preserve stained glass windows. Scientific results showed that the so-called isothermal glazing (i.e. ventilation by the air coming from the inside of the building) protected efficiently the ancient stained glass window from environmental attack (i.e. rain, pollutants, condensation, thermal shocks) with very limited secondary effects. The scientific research highlighted that its efficiency was strongly related to the technical design of the protective system. In particular, the ventilation and the size of the interspace had to be carefully considered. The research developed within the VIDRIO project was turned into general recommendations to the owners and practitioners on the best practice for the stained glass windows future conservation.
Keywords: A1 Journal article; Art; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.CULHER.2012.11.009
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“Elemental x-ray images obtained by grazing-exit electron probe microanalysis (GE-EPMA)”. Tsuji K, Nullens R, Wagatsuma K, Van Grieken RE, Journal of analytical atomic spectrometry 14, 1711 (1999). http://doi.org/10.1039/A905301H
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/A905301H
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“Extension of the river water quality model no. 1 with the fate of pesticides”. De Schepper VCJ, Holvoet KMA, Benedetti L, Seuntjens P, Vanrolleghem PA, Journal of hydroinformatics 14, 48 (2012). http://doi.org/10.2166/HYDRO.2011.028
Abstract: The existing River Water Quality Model No. 1 (RWQM1) was extended with processes determining the fate of non-volatile pesticides in the water phase and sediments. The exchange of pesticides between the water column and the sediment is described by three transport processes: diffusion, sedimentation and resuspension. Burial of sediments is also included. The modified model was used to simulate the concentrations of diuron and chloridazon in the river Nil. A good agreement was found between the simulated pesticide concentrations and measured values resulting from a four-month intensive monitoring campaign. The simulation results indicate that pesticide concentrations in the bulk water are not sensitive to the selected biochemical model parameters. it seems that these concentrations are mainly determined by the imposed upstream concentrations, run-off and direct losses. The high concentrations in the bulk water were not observed in the sediment pore water due to a limited exchange between the water column and the sediment. According to a sensitivity analysis, the observed pesticide concentrations are highly sensitive to the diffusion and sorption coefficients. Therefore, model users should determine these parameters with accuracy in order to reduce the degree of uncertainty in their results.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.2166/HYDRO.2011.028
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“Influence of sample thickness, excitation energy and geometry on particle size effects in XRF”. Van Dyck P, Markowicz A, Van Grieken R, X-ray spectrometry 14, 183 (1985). http://doi.org/10.1002/XRS.1300140409
Abstract: Expressions are presented for calculating the matrix effect and the pure particle size effect in the XRF analysis of particulate samples with a discrete particle size. The equations are based on the absorption-weighted radiometric diameter concept. Two excitationdetection geometries are considered, with the angles between the sample plane and both the incident and emerging radiation being either 90° (π geometry) or 45° (π/2 geometry). Calculations were made for different sample loadings and exciting radiation energies. The influence of these parameters on the matrix and pure particle size effects is shown. From the results, it is possible to predict the performances of alternative experimental correction procedures for the particle size effect, involving dual measurements at different excitation energies or in different excitationdetection geometries.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.1300140409
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“The Möbius phenomenon in Generalized Möbius-Listing surfaces and bodies, and Arnold's Cat phenomenon”. Gielis J, Ricci PE, Tavkhelidze I, Advanced Studies : Euro-Tbilisi Mathematical Journal 14, 17 (2021). http://doi.org/10.3251/ASETMJ/1932200812
Abstract: Möbius bands have been studied extensively, mainly in topology. Generalized Möbius-Listing surfaces and bodies providing a full geometrical generalization, is a quite new field, motivated originally by solutions of boundary value problems. Analogous to cutting of the original Möbius band, for this class of surfaces and bodies, results have been obtained when cutting such bodies or surfaces. In general, cutting leads to interlinked and intertwined different surfaces or bodies, resulting in very complex systems. However, under certain conditions, the result of cutting can be a single surface or body, which reduces complexity considerably. Our research is motivated by this reduction of complexity. In the study of cutting Generalized Möbius-Listing bodies with polygons as cross section, the conditions under which a single body results, displaying the Möbius phenomenon of a one-sided body, have been determined for even and odd polygons. These conditions are based on congruence and rotational symmetry of the resulting cross sections after cutting, and on the knife cutting the origin. The Möbius phenomenon is important, since the process of cutting (or separation of zones in a GML body in general) then results in a single body, not in different, intertwined domains. In all previous works it was assumed that the cross section of the GML bodies is constant, but the main result of this paper is that it is sufficient that only one cross section on the whole GML structure meets the conditions for the Möbius phenomenon to occur. Several examples are given to illustrate this.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.3251/ASETMJ/1932200812
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“Real-time electrochemical screening of cocaine in lab and field settings with automatic result generation”. de Jong M, Van Echelpoel R, Langley AR, Eliaerts J, van den Berg J, De Wilde M, Somers N, Samyn N, De Wael K, Drug testing and analysis 14, 1471 (2022). http://doi.org/10.1002/DTA.3276
Abstract: This work presents the results of a novel application for the fast on-site screening of cocaine and its main cutting agents in suspicious and confiscated samples. The methodology behind the novel application consists of portable electrochemical detection coupled with a peak-recognition algorithm for automated result output generation, validated both in laboratory and field settings. Currently used field tests, predominantly colorimetric tests, are lacking accuracy, often giving false positive or negative results. This presses the need for alternative approaches to field testing. By combining portable electrochemical approaches with peak-recognition algorithms, an accuracy of 98.4% concerning the detection of cocaine was achieved on a set of 374 powder samples. In addition, the approach was tested on multiple 'smuggled', colored cocaine powders and cocaine mixtures in solid and liquid states, typically in matrices such as charcoal, syrup and clothing. Despite these attempts to hide cocaine, our approach succeeded in detecting cocaine during on-site screening scenarios. This feature presents an advantage over colorimetric and optical detection techniques, which can fail with colored sample matrices. This enhanced accuracy on smuggled samples will lead to increased efficiency in confiscation procedures in the field, thus significantly reducing societal economic and safety concerns and highlighting the potential for electrochemical approaches in on-the-spot identification of drugs of abuse.
Keywords: A1 Journal article; Pharmacology. Therapy; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
DOI: 10.1002/DTA.3276
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“Towards fully electrically controlled domain-wall logic”. Vermeulen BB, Raymenants E, Pham VT, Pizzini S, Sorée B, Wostyn K, Couet S, Nguyen VD, Temst K, AIP advances 14, 025030 (2024). http://doi.org/10.1063/9.0000811
Abstract: Utilizing magnetic tunnel junctions (MTJs) for write/read and fast spin-orbit-torque (SOT)-driven domain-wall (DW) motion for propagation, enables non-volatile logic and majority operations, representing a breakthrough in the implementation of nanoscale DW logic devices. Recently, current-driven DW logic gates have been demonstrated via magnetic imaging, where the Dzyaloshinskii-Moriya interaction (DMI) induces chiral coupling between perpendicular magnetic anisotropy (PMA) regions via an in-plane (IP) oriented region. However, full electrical operation of nanoscale DW logic requires electrical write/read operations and a method to pattern PMA and IP regions compatible with the fabrication of PMA MTJs. Here, we study the use of a Hybrid Free Layer (HFL) concept to combine an MTJ stack with DW motion materials, and He+ ion irradiation to convert the stack from PMA to IP. First, we investigate the free layer thickness dependence of 100-nm diameter HFL-MTJ devices and find an optimal CoFeB thickness, from 7 to 10 angstrom, providing high tunneling magnetoresistance (TMR) readout and efficient spin-transfer torque (STT) writing. We then show that high DMI materials, like Pt/Co, can be integrated into an MTJ stack via interlayer exchange coupling with the CoFeB free layer. In this design, DMI values suitable for SOT-driven DW motion are measured by asymmetric bubble expansion. Finally, we demonstrate that He+ irradiation reliably converts the coupled free layers from PMA to IP. These findings offer a path toward the integration of fully electrically controlled DW logic circuits.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1063/9.0000811
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Finizola e Silva M, Van Schoubroeck S, Cools J, Aboge DO, Ouma M, Olweny C, Van Passel S (2024) Local actors' perspectives on sustainable food value chains : evidence from a Q-methodology study in Kenya. 36–51
Abstract: Governments and international organizations are increasingly determined to create more sustainable food value chains (SFVCs). However, only little empirical evidence is available on how SFVCs are understood. Enquiring African food value chain actors allows gathering valuable insights into their perception of sustainability, which characteristics of sustainable food value chains they prioritize, and which obstacles to a sustainable transformation they identify. By means of a Q-methodology involving interviews with 33 Kenyan respondents, four perspectives were distinguished. The first perspective, “economic productivity and growth,” prioritizes economic growth and has only limited attention to the social dimension of sustainability. The second perspective, “food security and food availability,” believes that ensuring food security should be the key goal of SFVCs. The third perspective, “environment first,” is dedicated to the environmental dimension of sustainability; the perspective implies that protecting natural resources is the primary way to sustain this level of production. The fourth perspective, “transformative knowledge,” entails that by innovating and sharing knowledge, food value chains can become more sustainable in different areas. Overall, this study provides reliable insights into how Kenyan food value chain actors perceive sustainability in their sector and which elements they believe should be prioritized when rethinking food systems. The study results are valuable for policy-making to further define an SFVC in Kenya and to pave the way for a sustainable transformation of the food sector in developing countries.
Keywords: Administrative Services; A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM)
DOI: 10.1007/S13412-023-00854-5
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