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Author 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, C.J.; Pourtois, G.; Tokei, Z.
Title Alternative Metals: from ab initio Screening to Calibrated Narrow Line Models Type P1 Proceeding
Year 2018 Publication Proceedings of the IEEE ... International Interconnect Technology Conference T2 – IEEE International Interconnect Technology Conference (IITC), JUN 04-07, 2018, Santa Clara, CA Abbreviated Journal
Volume Issue Pages 154-156
Keywords P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000468672900051 Publication Date 2018-09-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-5386-4337-2; 978-1-5386-4337-2 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:160473 Serial 7436
Permanent link to this record
 

 
Author Van Turnhout, J.; Aceto, D.; Travert, A.; Bazin, P.; Thibault-Starzyk, F.; Bogaerts, A.; Azzolina-Jury, F.
Title Observation of surface species in plasma-catalytic dry reforming of methane in a novel atmospheric pressure dielectric barrier discharge in situ IR cell Type A1 Journal article
Year 2022 Publication Catalysis Science & Technology Abbreviated Journal Catal Sci Technol
Volume 12 Issue 22 Pages 6676-6686
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) We developed a novel in situ (i.e. inside plasma and during operation) IR dielectric barrier discharge cell allowing investigation of plasma catalysis in transmission mode, atmospheric pressure, flow conditions (WHSV similar to 0-50 000 mL g(-1) h(-1)), at relevant discharge voltages (similar to 0-50 kV) and frequencies (similar to 0-5 kHz). We applied it to study the IR-active surface species formed on a SiO2 support and on a 3 wt% Ru/SiO2 catalyst, which can help to reveal the important surface reaction mechanisms during the plasma-catalytic dry reforming of methane (DRM). Moreover, we present a technique for the challenging task of estimating the temperature of a catalyst sample in a plasma-catalytic system in situ and during plasma operation. We found that during the reaction, water is immediately formed at the SiO2 surface, and physisorbed formic acid is formed with a delay. As Ru/SiO2 is subject to greater plasma-induced heating than SiO2 (with a surface temperature increase in the range of 70-120 degrees C, with peaks up to 150 degrees C), we observe lower amounts of physisorbed water on Ru/SiO2, and less physisorbed formic acid formation. Importantly, the formation of surface species on the catalyst sample in our plasma-catalytic setup, as well as the observed conversions and selectivities in plasma conditions, can not be explained by plasma-induced heating of the catalyst surface, but must be attributed to other plasma effects, such as the adsorption of plasma-generated radicals and molecules, or the occurrence of Eley-Rideal reactions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000865542600001 Publication Date 2022-10-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2044-4753; 2044-4761 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 5
Call Number UA @ admin @ c:irua:191389 Serial 7185
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Author Bekaert, J.; Bringmans, L.; Milošević, M.V.
Title Ginzburg-Landau surface energy of multiband superconductors : derivation and application to selected systems Type A1 Journal article
Year 2023 Publication Journal of physics : condensed matter Abbreviated Journal
Volume 35 Issue 32 Pages 325602-325610
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) We determine the energy of an interface between a multiband superconducting and a normal half-space, in presence of an applied magnetic field, based on a multiband Ginzburg-Landau (GL) approach. We obtain that the multiband surface energy is fully determined by the critical temperature, electronic densities of states, and superconducting gap functions associated with the different band condensates. This furthermore yields an expression for the thermodynamic critical magnetic field, in presence of an arbitrary number of contributing bands. Subsequently, we investigate the sign of the surface energy as a function of material parameters, through numerical solution of the GL equations. Here, we consider two distinct cases: (i) standard multiband superconductors with attractive interactions, and (ii) a three-band superconductor with a chiral ground state with phase frustration, arising from repulsive interband interactions. Furthermore, we apply this approach to several prime examples of multiband superconductors, such as metallic hydrogen and MgB2, based on microscopic parameters obtained from first-principles calculations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000986281900001 Publication Date 2023-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984 ISBN Additional Links UA library record; WoS full record
Impact Factor 2.7 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 2.7; 2023 IF: 2.649
Call Number UA @ admin @ c:irua:196664 Serial 8875
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Author Sevik, C.; Bekaert, J.; Milošević, M.V.
Title Superconductivity in functionalized niobium-carbide MXenes Type A1 Journal article
Year 2023 Publication Nanoscale Abbreviated Journal
Volume 15 Issue 19 Pages 8792-8799
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) We detail the effects of Cl and S functionalization on the superconducting properties of layered (bulk) and monolayer niobium carbide (Nb2C) MXene crystals, based on first-principles calculations combined with Eliashberg theory. For bulk layered Nb2CCl2, the calculated superconducting transition temperature (T-c) is in very good agreement with the recently measured value of 6 K. We show that T-c is enhanced to 10 K for monolayer Nb2CCl2, due to an increase in the density of states at the Fermi level, and the corresponding electron-phonon coupling. We further demonstrate feasible gate- and strain-induced enhancements of T-c for both bulk-layered and monolayer Nb2CCl2 crystals, resulting in T-c values of around 38 K. In the S-functionalized Nb2CCl2 crystals, our calculations reveal the importance of phonon softening in understanding their superconducting properties. Finally, we predict that Nb3C2S2 in bulk-layered and monolayer forms is also superconducting, with a T-c of around 28 K. Considering that Nb2C is not superconducting in pristine form, our findings promote functionalization as a pathway towards robust superconductivity in MXenes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000976973900001 Publication Date 2023-04-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364; 2040-3372 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.7 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 6.7; 2023 IF: 7.367
Call Number UA @ admin @ c:irua:196711 Serial 8938
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Author Vanderveken, F.; Tyberkevych, V.; Talmelli, G.; Sorée, B.; Ciubotaru, F.; Adelmann, C.
Title Lumped circuit model for inductive antenna spin-wave transducers Type A1 Journal article
Year 2022 Publication Scientific reports Abbreviated Journal Sci Rep-Uk
Volume 12 Issue 1 Pages 3796-13
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) We derive a lumped circuit model for inductive antenna spin-wave transducers in the vicinity of a ferromagnetic medium. The model considers the antenna's Ohmic resistance, its inductance, as well as the additional inductance due to the excitation of ferromagnetic resonance or spin waves in the ferromagnetic medium. As an example, the additional inductance is discussed for a wire antenna on top of a ferromagnetic waveguide, a structure that is characteristic for many magnonic devices and experiments. The model is used to assess the scaling properties and the energy efficiency of inductive antennas. Issues related to scaling antenna transducers to the nanoscale and possible solutions are also addressed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000826474600050 Publication Date 2022-03-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.6 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 4.6
Call Number UA @ admin @ c:irua:190001 Serial 7180
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Author Borkowski, R.; Straub, M.; Ou, Y.; Lefevre, Y.; Jelić, Ž.L.; Lanneer, W.; Kaneda, N.; Mahadevan, A.; Hueckstaedt, V.; van Veen, D.; Houtsma, V.; Coomans, W.; Bonk, R.; Maes, J.
Title FLCS-PON : a 100 Gbit/s flexible passive optical network: concepts and field trial Type A1 Journal article
Year 2021 Publication Journal Of Lightwave Technology Abbreviated Journal J Lightwave Technol
Volume 39 Issue 16 Pages 5314-5324
Keywords A1 Journal article; Mass communications; Condensed Matter Theory (CMT)
Abstract (down) We demonstrate concepts and results of a field trial for a flexible-rate passive optical network (FLCS-PON), which delivers bitrates up to 100 Gbit/s and allows for adaptations in the transmission method to match the users' channel conditions and optimize throughput. FLCS-PON builds on top of the hardware ecosystem that will be developed for ITU-T 50 Gbit/s PON and employs three new ingredients: optical network unit (ONU) grouping, flexible modulation format, and flexible forward error correction (FEC) code rate. Together, these techniques take advantage of the optical distribution network (ODN) statistics to realize a system capable of more than twofold throughput increase compared to the upcoming 50 Gbit/s PON, but still able to support a full array of deployed fiber edge cases, which are problematic for legacy PONs. In this paper we explain the concepts behind enabling techniques of FLCS-PON. We then report on a field trial over a deployed fiber infrastructure, using a system consisting of one FLCS-PON OLT and two ONUs. We report both pre- and post-forward-error-correction (post-FEC) performance of our system, demonstrating achievable net bitrate over an operator's fiber infrastructure. We realize a downlink transmission at double the speed of ITU-T 50 Gbit/s PON for ONUs exhibiting lower optical path loss (OPL), while simultaneously continue to support ONUs at high OPLs. We additionally realize a record-high 31.5 dB loss budget for 100 Gbit/s transmission using a direct-detection ONU with an optical preamplifier.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000692209800017 Publication Date 2021-08-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0733-8724 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.671 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 3.671
Call Number UA @ admin @ c:irua:181586 Serial 6995
Permanent link to this record
 

 
Author Ryabova, A.S.; Istomin, S.Y.; Dosaev, K.A.; Bonnefont, A.; Hadermann, J.; Arkharova, N.A.; Orekhov, A.S.; Sena, R.P.; Saveleva, V.A.; Kerangueven, G.; Antipov, E., V.; Savinova, E.R.; Tsirlina, G.A.
Title Mn₂O₃ oxide with bixbyite structure for the electrochemical oxygen reduction reaction in alkaline media : highly active if properly manipulated Type A1 Journal article
Year 2021 Publication Electrochimica Acta Abbreviated Journal Electrochim Acta
Volume 367 Issue Pages 137378
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) We consider compositional and structural factors which can affect the activity of bixbyite alpha-Mn2O3 towards the oxygen reduction reaction (ORR) and the stability of this oxide in alkaline solution. We compare electrochemistry of undoped, Fe and Al-doped alpha-Mn2O3 with bixbyite structure and braunite Mn7SiO12 having bixbyite-related crystal structure, using the rotating disk electrode (RDE), the rotating ring-disk electrode (RRDE), and cyclic voltammetry (CV) techniques. All manganese oxides under study are stable in the potential range between the ORR onset and ca. 0.7 V vs. Reversible Hydrogen Electrode (RHE). It is found that any changes introduced in the bixbyite structure and/or composition of alpha-Mn2O3 lead to an activity drop in both the oxygen reduction and hydrogen peroxide reactions in this potential interval. For the hydrogen peroxide reduction reaction these modifications also result in a change in the nature of the rate-determining step. The obtained results confirm that due to its unique crystalline structure undoped alpha-Mn2O3 is the most ORR active (among currently available) Mn oxide catalyst and favor the assumption of the key role of the (111) surface of alpha-Mn2O3 in the very high activity of this material towards the ORR. (C) 2020 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000607621500013 Publication Date 2020-10-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-4686 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.798 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 4.798
Call Number UA @ admin @ c:irua:176080 Serial 6731
Permanent link to this record
 

 
Author Tiwari, S.; Vanherck, J.; Van de Put, M.L.; Vandenberghe, W.G.; Sorée, B.
Title Computing Curie temperature of two-dimensional ferromagnets in the presence of exchange anisotropy Type A1 Journal article
Year 2021 Publication Physical review research Abbreviated Journal
Volume 3 Issue 4 Pages 043024
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) We compare three first-principles methods of calculating the Curie temperature in two-dimensional (2D) ferromagnetic materials (FM), modeled using the Heisenberg model, and propose a simple formula for estimating the Curie temperature with high accuracy that works for all common 2D lattice types. First, we study the effect of exchange anisotropy on the Curie temperature calculated using the Monte Carlo (MC), the Green's function, and the renormalized spin-wave (RNSW) methods. We find that the Green's function method overestimates the Curie temperature in high-anisotropy regimes compared to the MC method, whereas the RNSW method underestimates the Curie temperature compared to the MC and the Green's function methods. Next, we propose a closed-form formula for calculating the Curie temperature of 2D FMs, which provides an estimate of the Curie temperature that is greatly improved over the mean-field expression for magnetic material screening. We apply the closed-form formula to predict the Curie temperature 2D magnets screened from the C2DB database and discover several high Curie temperature FMs, with Fe2F2 and MoI2 emerging as the most promising 2D ferromagnets. Finally, by comparing to experimental results for CrI3, CrCl3, and CrBr3, we conclude that for small effective anisotropies, the Green's-function-based equations are preferable, while for larger anisotropies, MC-based results are more predictive.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000707506500001 Publication Date 2021-10-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access OpenAccess
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:182522 Serial 6975
Permanent link to this record
 

 
Author Deylgat, E.; Chen, E.; Fischetti, M.V.; Sorée, B.; Vandenberghe, W.G.
Title Image-force barrier lowering in top- and side-contacted two-dimensional materials Type A1 Journal article
Year 2022 Publication Solid state electronics Abbreviated Journal Solid State Electron
Volume 198 Issue Pages 108458-4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) We compare the image-force barrier lowering (IFBL) and calculate the resulting contact resistance for four different metal-dielectric-two-dimensional (2D) material configurations. We analyze edge contacts in three different geometries (a homogeneous dielectric throughout, including the 2D layer; a homogeneous dielectric surrounding the 2D layer, both ungated and back gated) and also a top-contact assuming a homogeneous dielectric. The image potential energy of each configuration is determined and added to the Schottky energy barrier which is calculated assuming a textbook Schottky potential. For each configuration, the contact resistivity is calculated using the WKB approximation and the effective mass approximation using either SiO2 or HfO2 as the surrounding dielectric. We obtain the lowest contact resistance of 1 k Omega mu m by n-type doping an edge contacted transition metal-dichalcogenide (TMD) monolayer, sandwiched between SiO2 dielectric, with similar to 1012 cm-2 donor atoms. When this optimal configuration is used, the contact resistance is lowered by a factor of 50 compared to the situation when the IFBL is not considered.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000876289800003 Publication Date 2022-09-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1101 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.7 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 1.7
Call Number UA @ admin @ c:irua:191556 Serial 7312
Permanent link to this record
 

 
Author Deylgat, E.; Chen, E.; Sorée, B.; Vandenberghe, W.G.
Title Quantum transport study of contact resistance of edge- and top-contacted two-dimensional materials Type P1 Proceeding
Year 2023 Publication International Conference on Simulation of Semiconductor Processes and Devices : [proceedings] T2 – International Conference on Simulation of Semiconductor Processes and, Devices (SISPAD), SEP 27-29, 2023, Kobe, Japan Abbreviated Journal
Volume Issue Pages 45-48
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract (down) We calculate the contact resistance for an edge- and top-contacted 2D semiconductor. The contact region consists of a metal contacting a monolayer of MoS2 which is otherwise surrounded by SiO2. We use the quantum transmitting boundary method to compute the contact resistance as a function of the 2D semiconductor doping concentration. An effective mass Hamiltonian is used to describe the properties of the various materials. The electrostatic potentials are obtained by solving the Poisson equation numerically. We incorporate the effects of the image-force barrier lowering on the Schottky barrier and examine the impact on the contact resistance. At low doping concentrations, the contact resistance of the top contact is lower compared to edge contact, while at high doping concentrations, the edge contact exhibits lower resistance.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001117703800012 Publication Date 2023-11-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-4-86348-803-8 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:202839 Serial 9079
Permanent link to this record
 

 
Author Bal, K.M.; Neyts, E.C.
Title Extending and validating bubble nucleation rate predictions in a Lennard-Jones fluid with enhanced sampling methods and transition state theory Type A1 Journal article
Year 2022 Publication Journal Of Chemical Physics Abbreviated Journal J Chem Phys
Volume 157 Issue 18 Pages 184113-10
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) We calculate bubble nucleation rates in a Lennard-Jones fluid through explicit molecular dynamics simulations. Our approach-based on a recent free energy method (dubbed reweighted Jarzynski sampling), transition state theory, and a simple recrossing correction-allows us to probe a fairly wide range of rates in several superheated and cavitation regimes in a consistent manner. Rate predictions from this approach bridge disparate independent literature studies on the same model system. As such, we find that rate predictions based on classical nucleation theory, direct brute force molecular dynamics simulations, and seeding are consistent with our approach and one another. Published rates derived from forward flux sampling simulations are, however, found to be outliers. This study serves two purposes: First, we validate the reliability of common modeling techniques and extrapolation approaches on a paradigmatic problem in materials science and chemical physics. Second, we further test our highly generic recipe for rate calculations, and establish its applicability to nucleation processes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000885260600002 Publication Date 2022-11-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.4 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 4.4
Call Number UA @ admin @ c:irua:192076 Serial 7266
Permanent link to this record
 

 
Author Clavel, J.; Lembrechts, J.; Lenoir, J.; Haider, S.; McDougall, K.; Nunez, M.A.; Alexander, J.; Barros, A.; Milbau, A.; Seipel, T.; Pauchard, A.; Fuentes-Lillo, E.; Backes, A.R.; Dar, P.; Reshi, Z.A.; Aleksanyan, A.; Zong, S.; Sierra, J.R.A.; Aschero, V.; Verbruggen, E.; Nijs, I.
Title Roadside disturbance promotes plant communities with arbuscular mycorrhizal associations in mountain regions worldwide Type A1 Journal article
Year 2024 Publication Ecography Abbreviated Journal
Volume Issue Pages e07051-14
Keywords A1 Journal article; Plant and Ecosystems (PLECO) – Ecology in a time of change
Abstract (down) We assessed the impact of road disturbances on the dominant mycorrhizal types in ecosystems at the global level and how this mechanism can potentially lead to lasting plant community changes. We used a database of coordinated plant community surveys following mountain roads from 894 plots in 11 mountain regions across the globe in combination with an existing database of mycorrhizal-plant associations in order to approximate the relative abundance of mycorrhizal types in natural and disturbed environments. Our findings show that roadside disturbance promotes the cover of plants associated with arbuscular mycorrhizal (AM) fungi. This effect is especially strong in colder mountain environments and in mountain regions where plant communities are dominated by ectomycorrhizal (EcM) or ericoid-mycorrhizal (ErM) associations. Furthermore, non-native plant species, which we confirmed to be mostly AM plants, are more successful in environments dominated by AM associations. These biogeographical patterns suggest that changes in mycorrhizal types could be a crucial factor in the worldwide impact of anthropogenic disturbances on mountain ecosystems. Indeed, roadsides foster AM-dominated systems, where AM-fungi might aid AM-associated plant species while potentially reducing the biotic resistance against invasive non-native species, often also associated with AM networks. Restoration efforts in mountain ecosystems will have to contend with changes in the fundamental make-up of EcM- and ErM plant communities induced by roadside disturbance.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001198654900001 Publication Date 2024-04-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0906-7590 ISBN Additional Links UA library record; WoS full record
Impact Factor 5.9 Times cited Open Access
Notes Approved Most recent IF: 5.9; 2024 IF: 4.902
Call Number UA @ admin @ c:irua:205605 Serial 9224
Permanent link to this record
 

 
Author Margui, E.; Hidalgo, M.; Queralt, I.; van Meel, K.; Fontas, C.
Title Analytical capabilities of laboratory, benchtop and handheld X-ray fluorescence systems for detection of metals in aqueous samples pre-concentrated with solid-phase extraction disks Type A1 Journal article
Year 2012 Publication Spectrochimica acta: part B : atomic spectroscopy Abbreviated Journal
Volume 67 Issue Pages 17-23
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) We aimed to achieve improved instrumental sensitivity and detection limits for the analysis of several elements (Cu, Ni, Zn, Pb and Cd) in aqueous samples with energy dispersive X-ray fluorescence spectrometry (EDXRF). The metals were pre-concentrated from aqueous solutions using commercially available organic-based solid-phase extraction (SPE) disks functionalized with iminodiacetate groups. These thin-layer organic materials provide an ideal support for XRF analysis. The elements were collected on the SPE extraction disks using a simple filtration procedure (starting with 1 L of aqueous sample) that allows direct XRF measurements to be performed in the field (in situ). We evaluated the analytical possibilities and drawbacks of using this pre-concentration procedure in combination with the following XRF configurations: a handheld unit, a benchtop EDXRF system and a high-energy polarized-beam EDXRF instrument (HE-P-EDXRF). Using the HE-P-EDXRF system, the detection limits for all metals were more than one order of magnitude lower than those attained using handheld and benchtop EDXRF instrumentation. For the detection of metal concentrations higher than similar to 20 mu g/L, however, handheld or benchtop systems remain a very good option due to their extreme simplicity of operation and low-cost, compact design. We demonstrate the application of these methodologies, using the three equipment systems, to the analysis of trace concentrations of metals in different types of aqueous samples, including tap water and waste water. (C) 2011 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000302757200003 Publication Date 2011-12-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0584-8547; 1873-3565 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:98338 Serial 7454
Permanent link to this record
 

 
Author Van Winckel, T.; Cools, J.; Vlaeminck, S.E.; Joos, P.; Van Meenen, E.; Borregán-Ochando, E.; Van Den Steen, K.; Geerts, R.; Vandermoere, F.; Blust, R.
Title Towards harmonization of water quality management : a comparison of chemical drinking water and surface water quality standards around the globe Type A1 Journal article
Year 2021 Publication Journal Of Environmental Management Abbreviated Journal J Environ Manage
Volume 298 Issue Pages 113447-12
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Centre for Research on Environmental and Social Change
Abstract (down) Water quality standards (WQS) set the legal definition for safe and desirable water. WQS impose regulatory concentration limits to act as a jurisdiction-specific legislative risk-management tool. Despite its importance in shaping a universal definition of safe, clean water, little information exists with respect to (dis)similarity of chemical WQS worldwide. Therefore, this paper compares chemical WQS for drinking and surface water matrices in eight jurisdictions representing a global geographic distribution: Australia, Brazil, Canada, China, the European Union, the region of Flanders in Belgium, the United States of America, and South Africa. The World Health Organization's list is used as a reference for drinking water standards. Sørensen–Dice indices (SDI) showed little qualitative similarity in the compounds that are regulated in drinking water (median SDI = 40%) and surface water (median SDI = 33%), indicating that the heterogeneity within a matrix is substantial at the level of the standard. Quantitative similarity for matching standards was higher than the qualitative per Kendall correlation (median = 0.73 and 0.58 for drinking water and surface water respectively), yet variance observed within standards remained inexplicably high for organic compounds. Variations in WQS were more pronounced for organic compounds. Most differences cannot be easily explained from a toxicological or risk-based point-of-view. Historical development, ease of measurement, and (toxicological) knowledge gaps on the risk of a vast number of organic compounds are theorized to be the drivers. Therefore, this study argues for a more tailored, risk-based approach in which standards incorporated into water safety plans are dynamically set for compounds that are persistent and could pose a risk for human health and/or aquatic ecosystems. Global variations in WQS should therefore not necessarily be avoided but rather globally harmonized with enough flexibility to ensure a global, up-to-date definition of safe and desirable water everywhere.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000700577400005 Publication Date 2021-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0301-4797 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.01 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 4.01
Call Number UA @ admin @ c:irua:180765 Serial 8681
Permanent link to this record
 

 
Author Meerburg, F.A.; Boon, N.; Van Winckel, T.; Pauwels, K.T.G.; Vlaeminck, S.E.
Title Live Fast, Die Young: Optimizing Retention Times in High-Rate Contact Stabilization for Maximal Recovery of Organics from Wastewater Type A1 Journal article
Year 2016 Publication Environmental science and technology Abbreviated Journal
Volume 50 Issue 17 Pages 9781-9790
Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) Wastewater is typically treated by the conventional activated sludge process, which suffers from an inefficient overall energy balance. The high-rate contact stabilization (HiCS) has been proposed as a promising primary treatment technology with which to maximize redirection of organics to sludge for subsequent energy recovery. It utilizes a feast famine cycle to select for bioflocculation, intracellular storage, or both. We optimized the HiCS process for organics recovery and characterized different biological pathways of organics removal and recovery. A total of eight HiCS reactors were operated at 15 degrees C at short solids retention times (SRT; 0.24-2.8 days), hydraulic contact times (t(c); 8 and 15 min), and stabilization times (t(s); 15 and 40 min). At an optimal SRT between 0.5 and 1.3 days and t(c) of 15 min and t(s) of 40 min, the HiCS system oxidized only 10% of influent chemical oxygen demand (COD) and recovered up to 55% of incoming organic matter into sludge. Storage played a minor role in the overall COD removal, which was likely dominated by aerobic biomass growth, bioflocculation onto extracellular polymeric substances, and settling. The HiCS process recovers enough organics to potentially produce 28 kWh of electricity per population equivalent per year by anaerobic digestion and electricity generation. This inspires new possibilities for energy-neutral wastewater treatment.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000382805800097 Publication Date 2016-08-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-936x; 1520-5851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:138270 Serial 8176
Permanent link to this record
 

 
Author Alemam, E.
Title Cleaning of wall paintings by Polyvinyl alcohol–Borax/Agarose (PVA–B/AG) double network hydrogels : characterization, assessment, and applications Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages 184 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Abstract (down) Wall paintings make up an important section of cultural heritage. They resemble time portals that can be used to travel back into the past and witness the life of our ancestors. In these paintings, the ancient artists depicted the different aspects of their life, such as cooking, baking, farming, manufacturing, as well as thoughts and beliefs. Unfortunately, wall paintings are susceptible to degradation over time in the form of the accumulations of dirt and deposits on the painted surfaces and loss of adhesion of the paint layers at the surface. Therefore, the removal of these deposits is one of the primary duties of conservator-restorers. Such operations are intended to restore the painted surface to a condition close enough to its original state. Since cleaning artworks may cause undesirable physicochemical alterations and is nonreversible, the proper cleaning procedure should be adopted. In this regard, numerous gels have been developed and exploited for the cleaning of various artwork surfaces. Lately, polyvinyl alcohol-borax (PVA-B) and agarose (AG) hydrogels have been widely employed as cleaning materials by conservator-restorers. However, both hydrogels have shown limitations in specific cleaning practices. In this work, we investigated a new double network hydrogel based on blending PVA-B and agarose to avoid the limitations posed by the constituting hydrogels. For this reason, a detailed characterization of the PVA–B/AG double network hydrogel was performed, including chemical structure, liquid phase retention, mechanical strength, rheological behavior, and self-healing behavior of various PVA-B/AG hydrogels. These new hydrogels revealed better properties than PVA-B and agarose hydrogels and obviated their limitations. A laboratory experiment on the removal of deteriorated Paraloid® B72 proved that the PVA-B/AG hydrogel loaded 10%/10% MEK/1-PeOH was able to remove these layers efficiently. Therefore, the hydrogel was tested on a wall painting from the Temple of Seti I in Abydos – Egypt. It removed the glossy/darkened consolidant from the wall painting and restored the original matt appearance of the painted surface. In another application on the painted ceiling of the same temple, the hydrogel was tested for removing thick soot layers. The hydrogel formulation (loaded with 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA) removed these layers with no noticeable damage to the paint layers. In a wide-scale application of the hydrogel (loaded with 10% propylene carbonate), it removed a highly deteriorated varnish layer from a 19-c wall painting. All the traditional cleaning methods employed caused damage to the paint layers, proving that gel cleaning can be a safer cleaning alternative in some cases.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:183381 Serial 7671
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Author Kulkarni, S.; Gonzalez-Quiroga, A.; Nuñez, M.; Schuerewegen, C.; Perreault, P.; Goel, C.; Heynderickx, G.J.; Van Geem, K.M.; Marin, G.B.
Title An experimental and numerical study of the suppression of jets, counterflow, and backflow in vortex units Type A1 Journal article
Year 2019 Publication AIChE journal Abbreviated Journal
Volume 65 Issue 8 Pages e16614-13
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) Vortex units are commonly considered for various single and multiphase applications due to their process intensification capabilities. The transition from gas‐only flow to gas–solid flow remains largely unexplored nonetheless. During this transition, primary flow phenomenon, jets, and secondary flow phenomena, counterflow and backflow, are substantially reduced, before a rotating solids bed is established. This transitional flow regime is referred to as the vortex suppression regime. In the present work, this flow transition is identified and validated through experimental and computational studies in two vortex units with a scale differing by a factor of 2, using spherical aluminum and alumina particles. This experimental data supports the proposed theoretical particle monolayer solids loading that allows estimation of vortex suppression regime solids capacity for any vortex unit. It is shown that the vortex suppression regime is established at a solids loading theoretically corresponding to a monolayer being formed in the unit for 1g‐Geldart D‐ and 1g‐Geldart B‐type particles. The model closely agrees with experimental vortex suppression range for both aluminum and alumina particles. The model, as well as the experimental data, shows that the flow suppression regime depends on unit dimensions, particle diameter, and particle density but is independent of gas flow rate. This combined study, based on experimental and computational data and on a theoretical model, reveals the vortex suppression to be one of the basic operational parameters to study flow in a vortex unit and that a simple monolayer model allows to estimate the needed solids loading for any vortex device to induce this flow transition.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000474620800026 Publication Date 2019-04-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-1541 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:162121 Serial 7945
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Author Gonzalez-Quiroga, A.; Shtern, V.; Perreault, P.; Vandewalle, L.; Marin, G.B.; Van Geem, K.M.
Title Intensifying mass and heat transfer using a high-g stator-rotor vortex chamber Type A1 Journal article
Year 2021 Publication Chemical Engineering And Processing Abbreviated Journal Chem Eng Process
Volume 169 Issue Pages 108638-11
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) Vortex reactors take advantage of the synergy between enhanced heat and mass transfer rates and multifunctional phenomena at different temporal and spatial scales. Proof-of-concept experiments with our novel and innovative STAtor-Rotor VOrtex Chamber (STARVOC) confirm its advantageous features for the sustainable production of chemicals and fuels. STARVOC is a high-g contactor that uses carrier flow (gas or liquid) tangential injection to drive a rotor attached to low-friction bearings. The vortex chamber inside the rotor contains a secondary phase or phases, such as a solids bed, a liquid layer, or a suspension. Carrier fluid passes through the perforated rotor wall and contacts a densely and uniformly distributed secondary phase with enhanced slip velocities. Experiments focused on pressure profiles, rotor angular velocity, and solids azimuthal velocity. With air as the carrier fluid and different solid particle beds as the secondary phase, STARVOC reached bed azimuthal velocities up to four-fold compared to those reached in Gas-Solid Vortex Units with fully static geometry. These results show its potential to improve interfacial heat and mass transfer rates and take advantage of flow energy and angular momentum. Due to its process intensification capabilities, STARVOC is a promising alternative for the state-of-the-art chemical industry.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000704946900008 Publication Date 2021-09-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0255-2701 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.234 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 2.234
Call Number UA @ admin @ c:irua:181062 Serial 8111
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Author Shi, W.; Pandey, T.; Lindsay, L.; Woods, L.M.
Title Vibrational properties and thermal transport in quaternary chalcogenides : the case of Te-based compositions Type A1 Journal article
Year 2021 Publication Physical review materials Abbreviated Journal
Volume 5 Issue 4 Pages 045401
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Vibrational thermal properties of CuZn2InTe4, AgZn2InTe4, and Cu2CdSnTe4, derived from binary II-VI zinc-blendes, are reported based on first-principles calculations. While the chalcogenide atoms in these materials have the same lattice positions, the cation atom arrangements vary, resulting in different crystal symmetries and subsequent properties. The compositional differences have important effects on the vibrational thermal characteristics of the studied materials, which demonstrate that low-frequency optical phonons hybridize with acoustic phonons and lead to enhanced phonon-phonon scattering and low lattice thermal conductivities. The phonon density of states, mode Gruneisen parameters, and phonon scattering rates are also calculated, enabling deeper insight into the microscopic thermal conduction processes in these materials. Compositional variations drive differences among the three materials considered here; nonetheless, their structural similarities and generally low thermal conductivities (0.5-4 W/mK at room temperature) suggest that other similar II-VI zinc-blende derived materials will also exhibit similarly low values, as also corroborated by experimental data. This, combined with the versatility in designing a variety of motifs on the overall structure, makes quaternary chalcogenides interesting for thermal management and energy conversion applications that require low thermal conductivity.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000655931400005 Publication Date 2021-04-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:179140 Serial 7045
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Author Bafekry, A.; Shahrokhi, M.; Shafique, A.; Jappor, H.R.; Fadlallah, M.M.; Stampfl, C.; Ghergherehchi, M.; Mushtaq, M.; Feghhi, S.A.H.; Gogova, D.
Title Semiconducting chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula with outstanding properties : a first-principles calculation study Type A1 Journal article
Year 2021 Publication ACS Omega Abbreviated Journal
Volume 6 Issue 14 Pages 9433-9441
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Very recently, a new class of the multicationic and -anionic entropy-stabilized chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula has been successfully fabricated and characterized experimentally [Zihao Deng et al., Chem. Mater. 32, 6070 (2020)]. Motivated by the recent experiment, herein, we perform density functional theory-based first-principles calculations in order to investigate the structural, mechanical, electronic, optical, and thermoelectric properties. The calculations of the cohesive energy and elasticity parameters indicate that the alloy is stable. Also, the mechanical study shows that the alloy has a brittle nature. The GeSnPbSSeTe alloy is a semiconductor with a direct band gap of 0.4 eV (0.3 eV using spin-orbit coupling effect). The optical analysis illustrates that the first peak of Im(epsilon) for the GeSnPbSSeTe alloy along all polarization directions is located in the visible range of the spectrum which renders it a promising material for applications in optical and electronic devices. Interestingly, we find an optically anisotropic character of this system which is highly desirable for the design of polarization-sensitive photodetectors. We have accurately predicted the thermoelectric coefficients and have calculated a large power factor value of 3.7 x 10(11) W m(-1) K-2 s(-1) for p-type. The high p-type power factor is originated from the multiple valleys near the valence band maxima. The anisotropic results of the optical and transport properties are related to the specific tetragonal alloy unit cell.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000640649500012 Publication Date 2021-03-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-1343 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access OpenAccess
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:178395 Serial 7017
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Author Biely, K.; Von Muenchhausen, S.; Van Passel, S.
Title Vertical integration as a strategy to increase value absorption by primary producers : the Belgian sugar beet and the German rapeseed case Type A1 Journal article
Year 2022 Publication AIMS Agriculture and Food Abbreviated Journal
Volume 7 Issue 3 Pages 659-682
Keywords A1 Journal article; Pharmacology. Therapy; Engineering Management (ENM)
Abstract (down) Vertical integration is a means of increasing market power. For some agricultural products, it is easier for farmers to exert control over their product beyond the farm gate, but for others it is more difficult. Cases in the latter category have two main characteristics. First, the farmer cannot sell the respective product to final consumers without processing. Second, processing is capital-intensive. Consequently, farmers have limited sales channels, and vertical integration of the supply chain is complex and challenging. It implies cooperation among farmers to process the raw material at a profitable scale and to finance the installation of processing facilities. Thus, for these product categories, farmers are prone to market power issues, since they depend on private businesses that have the financial means to install processing facilities and the logistical capacities to organize the collection of large amounts of raw material. This paper aims to identify and analyze the role of supply chain integration for farmers who are already cooperating horizontally. Two case studies serve as the basis for the analysis: sugar beet in Flanders, Belgium, and oilseed rape in Hessen, Germany. The analysis is based on a qualitative research approach combining interviews, focus groups, and workshops with farmers and processors. While for sugar beet, the effects of market power are emerging only now with the termination of the quota system, farmers growing oilseed rape have been experiencing these problems since the 1990s. Our analysis concludes that most strategies to maintain or improve farm income have been exhausted. Even various forms of vertical integration supported by European policies do not necessarily work as a successful strategy.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000860666800001 Publication Date 2022-08-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2471-2086 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.8 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 1.8
Call Number UA @ admin @ c:irua:191514 Serial 7374
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Author Grunert, O.; Reheul, D.; Van Labeke, M.-C.; Perneel, M.; Hernandez-Sanabria, E.; Vlaeminck, S.E.; Boon, N.
Title Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture Type A1 Journal article
Year 2016 Publication Microbial Biotechnology Abbreviated Journal
Volume 9 Issue 3 Pages 389-399
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) Vegetables and fruits are an important part of a healthy food diet, however, the eco-sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated Euro15.5 billion per year on inorganic fertilizers and the production of N-fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000374662600009 Publication Date 2016-03-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1751-7907 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:133617 Serial 8013
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Author Gebrehiwot, N.T.; Azadi, H.; Taheri, F.; Van Passel, S.
Title How participation in vegetables market affects livelihoods : empirical evidence from Northern Ethiopia Type A1 Journal article
Year 2018 Publication Journal of international food and agribusiness marketing Abbreviated Journal
Volume 30 Issue 2 Pages 107-131
Keywords A1 Journal article; Economics; Engineering Management (ENM)
Abstract (down) Vegetable farmers face a number of challenges in marketing. Having first-hand information about vegetable marketing is essential to devise appropriate strategies aimed at enhancing the value of the vegetable chain. It was in line with this view that the study was conducted to characterize vegetable markets in Northern Ethiopia. In an effort to identify the factors influencing vegetable marketing among farmers, data were collected from 283 farm households who were selected using stratified random sampling. Furthermore, the data were triangulated through focus group discussion (FGD) and key informant interviews. Descriptive statistics and the binary logistic regression model were used to identify the variables and test the probability of their influence in regard to farmers decisions in vegetable marketing. From the 13 explanatory variables included in the binary logistic regression model, six predictors were found to be statistically significant in determining the effects of participation decision on vegetable market. These variables are as follows: household family size, total land holding of the household, amount of vegetable produced and marketed, use of irrigation technologies, contact with extension agents, and access to market information. Relying on a survey result and observations, the findings of the study indicated that vegetable marketing is significantly improving the livelihood of smallholder producers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2017-12-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4438 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:154141 Serial 6210
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Author Kandemir, A.; Ozden, A.; Cagin, T.; Sevik, C.
Title Thermal conductivity engineering of bulk and one-dimensional Si-Ge nanoarchitectures Type A1 Journal article
Year 2017 Publication Science and technology of advanced materials Abbreviated Journal
Volume 18 Issue 1 Pages 187-196
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (down) Various theoretical and experimental methods are utilized to investigate the thermal conductivity of nanostructured materials; this is a critical parameter to increase performance of thermoelectric devices. Among these methods, equilibrium molecular dynamics (EMD) is an accurate technique to predict lattice thermal conductivity. In this study, by means of systematic EMD simulations, thermal conductivity of bulk Si-Ge structures (pristine, alloy and superlattice) and their nanostructured one dimensional forms with square and circular cross-section geometries (asymmetric and symmetric) are calculated for different crystallographic directions. A comprehensive temperature analysis is evaluated for selected structures as well. The results show that one-dimensional structures are superior candidates in terms of their low lattice thermal conductivity and thermal conductivity tunability by nanostructuring, such as by diameter modulation, interface roughness, periodicity and number of interfaces. We find that thermal conductivity decreases with smaller diameters or cross section areas. Furthermore, interface roughness decreases thermal conductivity with a profound impact. Moreover, we predicted that there is a specific periodicity that gives minimum thermal conductivity in symmetric superlattice structures. The decreasing thermal conductivity is due to the reducing phonon movement in the system due to the effect of the number of interfaces that determine regimes of ballistic and wave transport phenomena. In some nanostructures, such as nanowire superlattices, thermal conductivity of the Si/Ge system can be reduced to nearly twice that of an amorphous silicon thermal conductivity. Additionally, it is found that one crystal orientation, <100>, is better than the <111> crystal orientation in one-dimensional and bulk SiGe systems. Our results clearly point out the importance of lattice thermal conductivity engineering in bulk and nanostructures to produce high-performance thermoelectric materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000405949800001 Publication Date 2017-03-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1468-6996; 1878-5514 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:193772 Serial 8662
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Author Peeters, H.; Lenaerts, S.; Verbruggen, S.W.
Title Benchmarking the photocatalytic self-cleaning activity of industrial and experimental materials with ISO 27448:2009 Type A1 Journal article
Year 2023 Publication Materials Abbreviated Journal Materials
Volume 16 Issue 3 Pages 1119-13
Keywords A1 Journal article; Engineering sciences. Technology
Abstract (down) Various industrial surface materials are tested for their photocatalytic self-cleaning activity by performing the ISO 27448:2009 method. The samples are pre-activated by UV irradiation, fouled with oleic acid and irradiated by UV light. The degradation of oleic acid over time is monitored by taking water contact angle measurements using a contact angle goniometer. The foulant, oleic acid, is an organic acid that makes the surface more hydrophobic. The water contact angle will thus decrease over time as the photocatalytic material degrades the oleic acid. In this study, we argue that the use of this method is strongly limited to specific types of surface materials, i.e., only those that are hydrophilic and smooth in nature. For more hydrophobic materials, the difference in the water contact angles of a clean surface and a fouled surface is not measurable. Therefore, the photocatalytic self-cleaning activity cannot be established experimentally. Another type of material that cannot be tested by this standard are rough surfaces. For rough surfaces, the water contact angle cannot be measured accurately using a contact angle goniometer as prescribed by the standard. Because of these limitations, many potentially interesting industrial substrates cannot be evaluated. Smooth samples that were treated with an in-house developed hydrophilic titania thin film (PCT/EP2018/079983) showed a great photocatalytic self-cleaning performance according to the ISO standard. Apart from discussing the pros and cons of the current ISO standard, we also stress how to carefully interpret the results and suggest alternative testing solutions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000930734100001 Publication Date 2023-01-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1996-1944 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.4 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.4; 2023 IF: 2.654
Call Number UA @ admin @ c:irua:193337 Serial 7284
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Author Leysen, L.; Roekens, E.; Komy, Z.; Van Grieken, R.
Title A study of the weathering of an historic building Type A1 Journal article
Year 1987 Publication Analytica chimica acta Abbreviated Journal
Volume 195 Issue Pages 247-255
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) Various bulk and surface analytical techniques were used to study the chemical deterioration of the 13th-to-15th century limestone cathedral in Mechelen, Belgium. The weathering crust on the walls was found to be rich in sulfate, regardless of the geographic orientation. Nitrate and chloride were only detected in minor amounts in the crust and run-off samples. Attack by gaseous sulfur compounds seems to play a dominant role in the stone deterioration mechanism. Electron microprobe analysis showed predominantly bar-shaped gypsum crystals in the crust, and laser microprobe mass spectrometry showed that carbon seems to be responsible for the blackness of most crust samples. Automated electron microprobe analysis also indicated significant differences in the analytical composition of suspensions in run-off water and in rain-water.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos A1987K019500022 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2670; 1873-4324 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:116446 Serial 8608
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Author Zhang, G.; Huang, S.; Chaves, A.; Yan, H.
Title Black phosphorus as tunable Van der Waals quantum wells with high optical quality Type A1 Journal article
Year 2023 Publication ACS nano Abbreviated Journal
Volume 17 Issue 6 Pages 6073-6080
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) Van der Waals quantum wells, naturally formed in two-dimensional layered materials with nanoscale thickness, possess many inherent advantages over conventional molecular beam epitaxy grown counterparts, and could bring up intriguing physics and applications. However, optical transitions originated from the series of quantized states in these emerging quantum wells are still elusive. Here, we show that multilayer black phosphorus appears to be an excellent candidate for van der Waals quantum wells with well-defined subbands and high optical quality. Using infrared absorption spectroscopy, we probe subband structures of multilayer black phosphorus with tens of atomic layers, revealing clear signatures for optical transitions with subband index as high as 10, far from what was attainable previously. Surprisingly, in addition to allowed transitions, an unexpected series of “forbidden” transitions is also evidently observed, which enables us to determine energy spacings separately for conduction and valence subbands. Furthermore, the linear tunability of subband spacings by temperature and strain is demonstrated. Our results are expected to facilitate potential applications for infrared optoelectronics based on tunable van der Waals quantum wells.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000953463300001 Publication Date 2023-03-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 17.1 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 17.1; 2023 IF: 13.942
Call Number UA @ admin @ c:irua:196100 Serial 7565
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Author Vermeulen, B.B.; Raymenants, E.; Pham, V.T.; Pizzini, S.; Sorée, B.; Wostyn, K.; Couet, S.; Nguyen, V.D.; Temst, K.
Title Towards fully electrically controlled domain-wall logic Type A1 Journal article
Year 2024 Publication AIP advances Abbreviated Journal
Volume 14 Issue 2 Pages 025030-25035
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001163573400005 Publication Date 2024-02-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2158-3226 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:203823 Serial 9109
Permanent link to this record
 

 
Author Hasnat Rubel, A.
Title Theoretical characterization and optimization of nano-engineered superconducting scanning probe tip Type Doctoral thesis
Year 2023 Publication Abbreviated Journal
Volume Issue Pages viii, 145 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) Using state-of-the-art simulation methods, we optimized the performance of nanoscale superconducting scanning probe tips for advanced spatial imaging of magnetic fields. The systematic studies of the tips’ static properties as a function of the tilted magnetic field, geometric parameters, and material parameters were carried out. The sensitivity of different superconducting quantum interference devices (SQUIDs) to the magnetic field emanating from the magnetic nanoparticle, where the location of a magnetic nanoparticle is considered below the primary loop's center, was examined as a function of the primary and secondary loop dimensions. The main objective of the research was to characterize and optimize the performance of a nano-sized SQUID-on-tip (SOT) device. Optimal SOT sensitivity was sought, for different loop sizes, arm linewidth, and lead dimensions. Moreover, we revealed that a constriction in the loop arms of the SOT can substantially improve the sensitivity of the device. Finally, the properties of the theta-SOT device were examined in the presence of in-plane and out-of-plane magnetic field components, enabling nanoscale imaging of 3D distributions of the magnetic field. Altogether, the obtained results deliver an engineering solution for the optimum performance of the SOT device in desired conditions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:199494 Serial 8942
Permanent link to this record
 

 
Author Sanchez-Barriga, J.; Aguilera, I.; Yashina, L., V; Tsukanova, D.Y.; Freyse, F.; Chaika, A.N.; Callaert, C.; Abakumov, A.M.; Hadermann, J.; Varykhalov, A.; Rienks, E.D.L.; Bihlmayer, G.; Blugel, S.; Rader, O.
Title Anomalous behavior of the electronic structure of (Bi1-xInx)2Se3across the quantum phase transition from topological to trivial insulator Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal
Volume 98 Issue 23 Pages 235110
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000452322800003 Publication Date 2018-12-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:156240 Serial 7462
Permanent link to this record