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Author Broers, F.T.H.; Verslype, I.; Bossers, K.W.; Vanmeert, F.; Gonzalez, V.; Garrevoet, J.; van Loon, A.; va Duijn, E.; Krekeler, A.; De Keyser, N.; Steeman, I.; Noble, P.; Janssens, K.; Meirer, F.; Keune, K.
Title Correlated x-ray fluorescence and ptychographic nano-tomography on Rembrandt's The Night Watch reveals unknown lead “layer” Type A1 Journal article
Year 2023 Publication Science Advances Abbreviated Journal
Volume 9 Issue 50 Pages eadj9394-13
Keywords A1 Journal article; Engineering sciences. Technology; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Abstract (down) The Night Watch, one of the most famous masterpieces by Rembrandt, is the subject of a large research and conservation project. For the conservation treatment, it is of great importance to understand its current condition. Correlated nano-tomography using x-ray fluorescence and ptychography revealed a-so far unknown-lead-containing “layer”, which likely acts as a protective impregnation layer applied on the canvas before the quartz-clay ground was applied. This layer might explain the presence of lead soap protrusions in areas where no other lead components are present. In addition to the three-dimensional elemental mapping, ptychography visualizes and quantifies components not detectable by hard x-ray fluorescence such as the organic fraction and quartz. The first-time use of this combination of synchrotron-based techniques on a historic paint micro-sample shows it to be an important tool to better interpret the results of noninvasive imaging techniques operating on the macroscale.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001142514700010 Publication Date 2023-12-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2375-2548 ISBN Additional Links UA library record; WoS full record
Impact Factor 13.6 Times cited Open Access
Notes Approved Most recent IF: 13.6; 2023 IF: NA
Call Number UA @ admin @ c:irua:203849 Serial 9016
Permanent link to this record
 

 
Author Sarikurt, S.; Çakir, D.; Keceli, M.; Sevik, C.
Title The influence of surface functionalization on thermal transport and thermoelectric properties of MXene monolayers Type A1 Journal article
Year 2018 Publication Nanoscale Abbreviated Journal
Volume 10 Issue 18 Pages 8859-8868
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) The newest members of a two-dimensional material family, involving transition metal carbides and nitrides (called MXenes), have garnered increasing attention due to their tunable electronic and thermal properties depending on the chemical composition and functionalization. This flexibility can be exploited to fabricate efficient electrochemical energy storage (batteries) and energy conversion (thermoelectric) devices. In this study, we calculated the Seebeck coefficients and lattice thermal conductivity values of oxygen terminated M2CO2 (where M = Ti, Zr, Hf, Sc) monolayer MXene crystals in two different functionalization configurations (model-II (MD-II) and model-III (MD-III)), using density functional theory and Boltzmann transport theory. We estimated the thermoelectric figure-of-merit, zT, of these materials by two different approaches, as well. First of all, we found that the structural model (i.e. adsorption site of oxygen atom on the surface of MXene) has a paramount impact on the electronic and thermoelectric properties of MXene crystals, which can be exploited to engineer the thermoelectric properties of these materials. The lattice thermal conductivity kappa(l), Seebeck coefficient and zT values may vary by 40% depending on the structural model. The MD-III configuration always has the larger band gap, Seebeck coefficient and zT, and smaller kappa(l) as compared to the MD-II structure due to a larger band gap, highly flat valence band and reduced crystal symmetry in the former. The MD-III configuration of Ti2CO2 and Zr2CO2 has the lowest kappa(l) as compared to the same configuration of Hf2CO2 and Sc2CO2. Among all the considered structures, the MD-II configuration of Hf2CO2 has the highest kappa(l), and Ti2CO2 and Zr2CO2 in the MD-III configuration have the lowest kappa(l). For instance, while the band gap of the MD-II configuration of Ti2CO2 is 0.26 eV, it becomes 0.69 eV in MD-III. The zT(max) value may reach up to 1.1 depending on the structural model of MXene.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000432096400055 Publication Date 2018-04-06
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 Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:193788 Serial 8654
Permanent link to this record
 

 
Author Ravindra, K.; Stranger, M.; Van Grieken, R.
Title Chemical characterization and multivariate analysis of atmospheric PM2.5 particles Type A1 Journal article
Year 2008 Publication Journal of atmospheric chemistry Abbreviated Journal
Volume 59 Issue 3 Pages 199-218
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The new European Council Directive (PE-CONS 3696/07) frames the inhalable (PM10) and fine particles (PM2.5) on priority to chemically characterize these fractions in order to understand their possible relation with health effects. Considering this, PM2.5 was collected during four different seasons to evaluate the relative abundance of bulk elements (Cl, S, Si, Al, Br, Cu, Fe, Ti, Ca, K, Pb, Zn, Ni, Mn, Cr and V) and water soluble ions (F−, Cl−, NO2 −, NO3 −, SO4 2−, Na+, NH4 +, Ca2+ and Mg2+) over Menen, a Belgian city near the French border. The air quality over Menen is influenced by industrialized regions on both sides of the border. The most abundant ionic species were NO3 −, SO4 2− and NH4 +, and they showed distinct seasonal variation. The elevated levels of NO3 − during spring and summer were found to be related to the larger availability of the NOx precursor. The various elemental species analyzed were distinguished into crustal and anthropogenic source categories. The dominating elements were S and Cl in the PM2.5 particles. The anthropogenic fraction (e.g. Zn, Pb, and Cu) shows a more scattered abundance. Furthermore, the ions and elemental data were also processed using principal component analysis and cluster analysis to identify their sources and chemistry. These approach identifies anthropogenic (traffic and industrial) emissions as a major source for fine particles. The variations in the natural/anthropogenic fractions of PM2.5 were also found to be a function of meteorological conditions as well as of long-range transport of air masses from the industrialized regions of the continent.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000258087700004 Publication Date 2008-07-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0167-7764 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:70640 Serial 7643
Permanent link to this record
 

 
Author Van Grieken, R.; Speecke, A.; Hoste, J.
Title Spatial neutron flux distributions around A 14 MeV neutron generator Type A3 Journal article
Year 1972 Publication Journal of radioanalytical chemistry Abbreviated Journal
Volume 10 Issue 1 Pages 95-104
Keywords A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The neutron flux distribution in the vicinity of 30, 20 and 10 mm diameter targets is measured by irradiating concentric ring-type iron monitors at different distances from the target and counting the induced56Mn activity. Considering the many uncertainties, satisfactory agreement was found between theory and experiment.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2006-11-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0134-0719; 2064-2857 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:116452 Serial 8567
Permanent link to this record
 

 
Author Borah, R.; Kumar, A.; Samantaray, M.; Desai, A.; Tseng, F.-G.
Title Photothermal heating of Au nanorods and nanospheres : temperature characteristics and strength of convective forces Type A1 Journal article
Year 2023 Publication Plasmonics Abbreviated Journal
Volume 18 Issue 4 Pages 1449-1465
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The nanoscale photothermal effect and the optofluidic convection around plasmonic nanoparticles drive the application of such nanoparticles in micro-environment. In this work, heat transfer and fluid flow around Au nanospheres and nanorods in water medium under continuous and pulsed wave laser irradiance was investigated using an FEM based numerical framework. Au nanospheres of a wide range of diameter: 40 nm = Diameter (D) = 180 nm and relatively large nanorods (diameter: 50 nm) with varying aspect ratio (1 = Aspect ratio (A) = 5) and orientation (0 degrees = ? = 90 degrees, ? = 0 degrees, 90 degrees) with respect to the incident EM radiation were investigated for continuous wave (CW) and pulsed wave laser. It was found that although nanorods can attain much higher temperature than nanospheres, orientation of a nanorod is an important factor to be carefully considered in applications. In micro-scale spherical and hemispherical confinements (diameter < 14.4 p.m), the convective velocity fields around nanoparticles is in the order of 10-9 m/s, with only a weak effect of the slip or no-slip boundary condition on the confining walls. Importantly, the size of the confinement has a strong effect leading to an order of magnitude stronger convection for 14.4 p.m (diameter) spherical confinement as compared to 3.6 p.m confinement. Additionally close proximity of the nanoparticles to the confining walls strongly reduces (by an order of magnitude) the convective currents. The results reported herein provides important insights for the use of photothermal nanoparticles in microscale confined space (e.g. cellular environment) for applications such as optical tweezers, photoporation, etc.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000985445100001 Publication Date 2023-05-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1557-1955; 1557-1963 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 3; 2023 IF: 2.139
Call Number UA @ admin @ c:irua:197380 Serial 8914
Permanent link to this record
 

 
Author Van de Voorde, L.; Vandevijvere, M.; Vekemans, B.; Van Pevenage, J.; Caen, J.; Vandenabeele, P.; van Espen, P.; Vincze, L.
Title Study of a unique 16th century Antwerp majolica floor in the Rameyenhof castle's chapel by means of X-ray fluorescence and portable Raman analytical instrumentation Type A1 Journal article
Year 2014 Publication Spectrochimica acta: part B : atomic spectroscopy Abbreviated Journal
Volume 102 Issue Pages 28-35
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Abstract (down) The most unique and only known 16th century Antwerp majolica tile floor in Belgium is situated in a tower of the Rameyenhof castle (Gestel, Belgium). This exceptional work of art has recently been investigated in situ by using X-ray fluorescence (XRF) and Raman spectroscopy in order to study the material characteristics. This study reports on the result of the analyses based on the novel combination of non-destructive and portable instrumentation, including a handheld XRF spectrometer for obtaining elemental information and a mobile Raman spectrometer for retrieving structural and molecular information on the floor tiles in the Rameyenhof castle and on a second, similar medallion, which is stored in the Rubens House museum in Antwerp (Belgium). The investigated material, majolica, is a type of ceramic, which fascinated many people and potters throughout history by its beauty and colourful appearance. In this study the characteristic major/minor and trace element signature of 16th century Antwerp majolica is determined and the pigments used for the colourful paintings present on the floor are identified. Furthermore, based on the elemental fingerprint of the white glaze, and in particular on the presence of zinc in the tiles – an element that was not used for making 16th century majolica – valuable information about the originality of the chapel floor and the two central medallions is acquired. (C) 2014 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000347604100005 Publication Date 2014-10-25
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:123850 Serial 8592
Permanent link to this record
 

 
Author Shi, R.; Choudhuri, D.; Kashiwar, A.; Dasari, S.; Wang, Y.; Banerjee, R.; Banerjee, D.
Title α phase growth and branching in titanium alloys Type A1 Journal article
Year 2021 Publication Philosophical magazine Abbreviated Journal Philos Mag
Volume Issue Pages
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) The morphology and spatial distribution of alpha (α) precipitates have been mapped as a function of Mo content in Ti-Mo binary alloys employing a combinatorial approach. Heat-treatments were carried out on compositionally graded Ti-xMo samples processed using a rapid throughput laser engineered net shape (LENS) process. The composition space spans 1.5 at% to 6 at% Mo with ageing at 750°C, 650°C and 600°C following a β solution treatment. Three distinct regimes of α morphology and distribution were observed. These are colony-dominated microstructures originating from grain boundary α allotriomorphs, bundles of intragranular α laths, and homogeneously distributed individual fine-scale α laths. Branching of the α precipitates was observed in all these domains in a manner reminiscent of solid-state dendritic growth. The phenomenon is particularly apparent at low volume fractions of α. Similar features are present in a wide variety of alloy compositions. 3-dimensional features of such branched structures have been analysed. Simulation of the branching process by phase field methods incorporating anisotropy in the α/β interface energy and elasticity suggests that it can be initiated at growth ledges present at broad faces of the α laths, driven by the enhancement of the diffusion flux at these steps. The dependence of branching on various parameters such as supersaturation and diffusivity, and microstructural features like ledge height and distribution and the presence of adjacent α variants has been evaluated.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000722082700001 Publication Date 2021-11-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1478-6435 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.505 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 1.505
Call Number UA @ admin @ c:irua:183616 Serial 6849
Permanent link to this record
 

 
Author Piñera, I.; Cruz, C.M.; van Espen, P.; Abreu, Y.; Leyva, A.
Title Study of dpa distributions in electron irradiated YBCO slabs through MCCM algorithm Type A1 Journal article
Year 2012 Publication Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms Abbreviated Journal
Volume 274 Issue Pages 191-194
Keywords A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The Monte Carlo assisted Classical Method (MCCM) consists on a calculation procedure for determining the displacements per atom (dpa) distribution in solid materials. This algorithm allows studying the gamma and electron irradiation damage in different materials. It is based on the electrons elastic scattering classic theories and the use of Monte Carlo simulation for the physical processes involved. The present study deals with the Monte Carlo simulation of electron irradiation effects on YBa2Cu3O7-x (YBCO) slabs using the MCNPX code system. Displacements per atom distributions are obtained through the MCCM for electron irradiation up to 10 MeV. In-depth dpa profiles for electrons and positrons are obtained and analysed. Also, dpa contributions from each atomic specie in the material are calculated. It was found that the dpa distribution is more homogeneous in the material volume when increasing energy of incident electrons. Also, the dpa produced by positrons has no relevance when irradiating with electrons, in contrast with previous similar gamma irradiation studies. All the results are presented and discussed in this contribution. (C) 2011 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000301611900031 Publication Date 2011-12-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-583x 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:97819 Serial 8595
Permanent link to this record
 

 
Author Gielis, J.; Caratelli, D.; Fougerolle, Y.; Ricci, P.E.; Gerats, T.
Title A biogeometrical model for corolla fusion in Asclepiad flowers Type H1 Book chapter
Year 2017 Publication Abbreviated Journal
Volume 2 Issue Pages 83-105 T2 - Modeling in mathematics : proceedings
Keywords H1 Book chapter; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The molecular genetics of flower development have been studied extensively for more than two decades. Fusion of organs and the tendency to oligomery, important characteristics of flower evolution, so far have remained fairly elusive. We present a geometric model for shape and fusion in the corolla of Asclepiads. Examples demonstrate how fusion of petals creates stable centers, a prerequisite for the formation of complex pollination structures via congenital and postgenital fusion events, with the formation of de novo organs, specific to Asclepiads. The development of the corolla reduces to simple inequalities from the MATHS-BOX. The formation of stable centers and of bell and tubular shapes in flowers are immediate and logical consequences of the shape. Our model shows that any study on flowers, especially in evo-devo perspective should be performed within the wider framework of polymery and oligomery and of fusion and synorganization.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000442076400007 Publication Date 2017-04-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-94-6239-260-1; 978-94-6239-261-8; 2543-0300; 978-94-6239-260-1 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:144551 Serial 7561
Permanent link to this record
 

 
Author Worobiec, A.; Potgieter-Vermaak, S.; Brooker, A.; Darchuk, L.; Stefaniak, E.; Van Grieken, R.
Title Interfaced SEM/EDX and micro-Raman spectrometry for characterisation of heterogeneous environmental particles: fundamental and practical challenges Type A1 Journal article
Year 2010 Publication Microchemical journal Abbreviated Journal
Volume 94 Issue 1 Pages 65-72
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
Abstract (down) The molecular character of atmospheric particulate matter is of prime importance when interpreting air pollution trends and its subsequent influence on environmental monitoring and preventative conservation. The known methods of estimating the molecular composition normally involve elemental analysis of particles (both as bulk and computer controlled analyses of single particles) with subsequent multivariate analyses to clusterise the elements in groups of elements that are closely related to each other. With this approach one can at best suggest associations. Evidently the application of molecular spectroscopy in addition to elemental concentration profiles would provide intimate information regarding the nature of the particles and consequently their fate. This paper gives an overview of research performed in our laboratory and describes the optimisation of experimental parameters to use scanning electron microscopy with energy-dispersive X-ray detection (SEM/EDX) or electron probe X-ray microanalysis (EPXMA) in parallel with micro-Raman Spectrometry (MRS) to investigate single environmental particles. The challenges associated with the two stand-alone techniques are revealed and consequently those posed with an interfaced approach are discussed. Preliminary results, of an initial investigation of the SEM/EDX interfaced with MRS to ultra-fine heterogeneous environmental particles, are given.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000273238800011 Publication Date 2009-09-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0026-265x; 0026-265x 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:79801 Serial 8114
Permanent link to this record
 

 
Author Peng, L.; Liu, Y.; Sun, J.; Wang, D.; Dai, X.; Ni, B.-J.
Title Enhancing immobilization of arsenic in groundwater: A model-based evaluation Type A1 Journal article
Year 2017 Publication Journal of cleaner production Abbreviated Journal
Volume 166 Issue Pages 449-457
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The mobilization of arsenic (As) in aquatic environment (groundwater) can cause severe environmental and healthy issues. To develop remediation strategies, we proposed a comprehensive mathematical model to describe the As removal in a arsenite (As (III)) oxidizing and ferrous iron (Fe (II)) oxidizing denitrifying granular biofilm system. In the model framework, the growth-linked microbial oxidation of As (III) and Fe (II) was coupled to chemolithotrophic denitrification of one-step reduction of nitrate to nitrogen gas. Meanwhile, the precipitation of ferric iron (Fe (III)) and adsorption of arsenate (As (V)) onto the biogenic Fe (III) (hydr)oxides were also considered. The model was calibrated by comparing the model predictions against experimental data from batch experiments. The validity of the model was further demonstrated through testing against long-term experimental results from five independent bioreactors with different reactor configurations and operational conditions. Modeling results revealed that the granule size would exert a limited impact on arsenic and iron removal. Nevertheless, their removal efficiencies increased rapidly with the increase of hydraulic retention time (HRT) from 1 h to 12 h, but became independent of HRT as it further increased. The established model framework enables interpretation of a range of experimental observations on As and Fe removal and helps to identify the optimal conditions for enhanced arsenic remediation. (C) 2017 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000412607100046 Publication Date 2017-08-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-6526 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:146635 Serial 7919
Permanent link to this record
 

 
Author Vizarim, N.P.
Title Dynamic behavior of Skyrmions under the influence of periodic pinning in chiral magnetic infinite thin films Type Doctoral thesis
Year 2023 Publication Abbreviated Journal
Volume Issue Pages 212 p.
Keywords Doctoral thesis; Condensed Matter Theory (CMT)
Abstract (down) The miniaturization of transistors for application in new processors and logic devices poses a significant challenge in the field of materials. Spintronics, which relies on controlled movement of magnetic nanostructures, offers a promising solution. Among the candidates, magnetic skyrmions are considered one of the most promising. These chiral spin structures, characterized by topological protection and enhanced stability compared to vortices or magnetic bubbles, have been extensively studied. To advance in the control of skyrmion motion, essential for practical applications, we investigated their dynamic behavior in a two-dimensional chiral magnet at zero temperature. Our study focused on the influence of periodic arrays of pinning centers. The simulations considered skyrmions as point-like particles considering the following interactions: skyrmion-skyrmion interactions, interactions with pinning center arrays, a current of polarized spins, and the Magnus force. We conducted calculations for scenarios involving a single skyrmion as well as different skyrmion density values in the material. The aim was to explore possibilities for controlled skyrmion motion, investigate different dynamic regimes, and examine collective effects. The results demonstrate that by adjusting the size, strength, and density of the pinning centers, we can effectively control the motion of individual skyrmions and manage the flow of multiple skyrmions. Furthermore, we discovered that periodic arrays of pinning centers can facilitate topological selection when different species of skyrmions with distinct Magnus components are present. Employing alternating currents, we observed the significant role of the ratchet effect in the skyrmion dynamics. By fine-tuning the amplitudes of the alternating currents, we achieved direct and controlled motion of skyrmions in specific directions. These findings hold potential for advancing our understanding of skyrmion dynamics and can inspire future technological applications involving these quasi-particles. Overall, we anticipate that our results will be valuable to the scientific community, contributing to a deeper comprehension of skyrmion dynamics and paving the way for future technological applications.
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:198101 Serial 8852
Permanent link to this record
 

 
Author Skaggs, C.M.; Kang, C.-J.; Perez, C.J.; Hadermann, J.; Emge, T.J.; Frank, C.E.; Pak, C.; Lapidus, S.H.; Walker, D.; Kotliar, G.; Kauzlarich, S.M.; Tan, X.; Greenblatt, M.
Title Ambient and high pressure CuNiSb₂ : metal-ordered and metal-disordered NiAs-type derivative pnictides Type A1 Journal article
Year 2020 Publication Inorganic Chemistry Abbreviated Journal Inorg Chem
Volume 59 Issue 19 Pages 14058-14069
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (down) The mineral Zlatogorite, CuNiSb2, was synthesized in the laboratory for the first time by annealing elements at ambient pressure (CuNiSb2-AP). Rietveld refinement of synchrotron powder X-ray diffraction data indicates that CuNiSb2-AP crystallizes in the NiAs-derived structure (P (3) over bar m1, #164) with Cu and Ni ordering. The structure consists of alternate NiSb6 and CuSb6 octahedral layers via face-sharing. The formation of such structure instead of metal disordered NiAs-type structure (P6(3)/mmc, #194) is validated by the lower energy of the ordered phase by first-principle calculations. Interatomic crystal orbital Hamilton population, electron localization function, and charge density analysis reveal strong Ni-Sb, Cu-Sb, and Cu-Ni bonding and long weak Sb-Sb interactions in CuNiSb2-AP. The magnetic measurement indicates that CuNiSb2-AP is Pauli paramagnetic. First-principle calculations and experimental electrical resistivity measurements reveal that CuNiSb2-AP is a metal. The low Seebeck coefficient and large thermal conductivity suggest that CuNiSb2 is not a potential thermoelectric material. Single crystals were grown by chemical vapor transport. The high pressure sample (CuNiSb2-8 GPa) was prepared by pressing CuNiSb2-AP at 700 degrees C and 8 GPa. However, the structures of single crystal and CuNiSb2-8 GPa are best fit with a disordered metal structure in the P (3) over bar m1 space group, corroborated by transmission electron microscopy.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000580381700028 Publication Date 2020-09-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669 ISBN Additional Links UA library record; WoS full record
Impact Factor 4.6 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 4.6; 2020 IF: 4.857
Call Number UA @ admin @ c:irua:174331 Serial 6714
Permanent link to this record
 

 
Author Penders, A.G.; Konstantinovic, M.J.; Yang, T.; Bosch, R.-w.; Schryvers, D.; Somville, F.
Title Microstructural investigation of IASCC crack tips extracted from thimble tube O-ring specimens Type A1 Journal article
Year 2022 Publication Journal of nuclear materials Abbreviated Journal J Nucl Mater
Volume 565 Issue Pages 153727-16
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) The microstructural features of intergranular irradiation-assisted stress corrosion crack tips from a redeemed neutron-irradiated flux thimble tube (60 dpa) have been investigated using focused-ion beam analysis and (scanning) transmission electron microscopy. The current work presents a close examination of the deformation field and oxide assembly associated with intergranular cracking, in addition to the analysis of radiation-induced segregation at leading grain boundaries. Evidence of stress induced martensitic transformation extending from the crack tips is presented. Intergranular crack arrest is demonstrated on the account of the external tensile stress orientation, and as a consequence of MnS inclusion particles segregating close to the fractured grain boundary. Exclusive observations of grain boundary oxidation prior to the cracking are presented, which is in full-agreement with the internal oxidation model.(c) 2022 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000799256300004 Publication Date 2022-04-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3115 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.1 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.1
Call Number UA @ admin @ c:irua:188609 Serial 7086
Permanent link to this record
 

 
Author Sui, Y.; Muys, M.; Vermeir, P.; D'Adamo, S.; Vlaeminck, S.E.
Title Light regime and growth phase affect the microalgal production of protein quantity and quality with Dunaliella salina Type A1 Journal article
Year 2019 Publication Bioresource technology Abbreviated Journal
Volume 275 Issue Pages 145-152
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The microalga Dunaliella salina has been widely studied for carotenogenesis, yet its protein production for human nutrition has rarely been reported. This study unveils the effects of growth phase and light regime on protein and essential amino acid (EAA) levels in D. salina. Cultivation under 24-h continuous light was compared to 12-h/12-h light/dark cycle. The essential amino acid index (EAAI) of D. salina showed accumulating trends up to 1.53 in the stationary phase, surpassing FAO/WHO standard for human nutrition. Light/dark conditions inferred a higher light-usage efficiency, yielding 597% higher protein and 1828% higher EAA mass on light energy throughout the growth, accompanied by 138% faster growth during the light phase of the light/dark cycle, compared to continuous light. The findings revealed D. salina to be especially suitable for high-quality protein production, particularly grown under light/dark conditions, with nitrogen limitation as possible trigger, and harvested in the stationary phase.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000456405000018 Publication Date 2018-12-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-8524 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:155981 Serial 8173
Permanent link to this record
 

 
Author Bernardi, A.; Becherini, F.; Verità, M.; Godoi, R.H.M.; Kontozova-Deutsch, V.; Van Grieken, R.; et al.
Title Conservation of stained glass windows with protective glazing : main results from the European VIDRIO research programme Type A1 Journal article
Year 2013 Publication Journal of cultural heritage Abbreviated Journal
Volume 14 Issue 6 Pages 527-536
Keywords A1 Journal article; Art; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000326937800009 Publication Date 2013-01-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1296-2074 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:111817 Serial 7726
Permanent link to this record
 

 
Author Török, S.; Van Dyck, P.; Van Grieken, R.
Title Heterogeneity effects in direct X-ray fluorescence analysis of hair Type A1 Journal article
Year 1984 Publication X-ray spectrometry Abbreviated Journal
Volume 13 Issue 1 Pages 27-32
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos A1984SB70200004 Publication Date 2005-05-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0049-8246 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:116485 Serial 8029
Permanent link to this record
 

 
Author Fenu, A.; De Wilde, W.; Gaertner, M.; Weemaes, M.; de Gueldre, G.; van de Steene, B.
Title Elaborating the membrane life concept in a full scale hollow-fibers MBR Type A1 Journal article
Year 2012 Publication Journal of membrane science Abbreviated Journal
Volume 421 Issue Pages 349-354
Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The membrane life-time has a strong impact on competitivity and viability of MBRs. This study critically analyzes the membrane life-time concept, approaching it through different assessment methods. A full scale MBR's membrane life-time was assessed on the following: (i) maintaining the permeate flow throughput to the MBR; (ii) the permeability decline; (iii) oxidative aging; (iv) the increase in energy costs; and (v) mechanical aging. The method based on permeability decline provides a membrane life-time estimate up to a theoretical end. It was further elaborated inherently to operations with no long-term flux decline. The increase in operating pressure remains the main end-of-life trigger for deciding when to replace membrane modules. On the contrary, mechanical and permeate flow throughput analysis of the data are not able to provide a clear estimate of the membrane life-time. As for the membrane life-time estimation based on chlorine contact, it was found to be too optimistic. Complete irreversible fouling occurs before maximum contact time with chlorine is reached. At end-of-life operating conditions, the energy consumption raised of 170% due to the reduced flow rate. The cost raise appears high but still affordable. Earlier membrane replacement thus can never be counterbalanced by energy costs saving. (C) 2012 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000308741100039 Publication Date 2012-08-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0376-7388 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:101790 Serial 7856
Permanent link to this record
 

 
Author Samae, V.; Cordier, P.; Demouchy, S.; Bollinger, C.; Gasc, J.; Koizumi, S.; Mussi, A.; Schryvers, D.; Idrissi, H.
Title Stress-induced amorphization triggers deformation in the lithospheric mantle Type A1 Journal article
Year 2021 Publication Nature Abbreviated Journal Nature
Volume 591 Issue 7848 Pages 82-86
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) The mechanical properties of olivine-rich rocks are key to determining the mechanical coupling between Earth's lithosphere and asthenosphere. In crystalline materials, the motion of crystal defects is fundamental to plastic flow(1-4.) However, because the main constituent of olivine-rich rocks does not have enough slip systems, additional deformation mechanisms are needed to satisfy strain conditions. Experimental studies have suggested a non-Newtonian, grain-size-sensitive mechanism in olivine involving grain-boundary sliding(5,6). However, very few microstructural investigations have been conducted on grain-boundary sliding, and there is no consensus on whether a single or multiple physical mechanisms are at play. Most importantly, there are no theoretical frameworks for incorporating the mechanics of grain boundaries in polycrystalline plasticity models. Here we identify a mechanism for deformation at grain boundaries in olivine-rich rocks. We show that, in forsterite, amorphization takes place at grain boundaries under stress and that the onset of ductility of olivine-rich rocks is due to the activation of grain-boundary mobility in these amorphous layers. This mechanism could trigger plastic processes in the deep Earth, where high-stress conditions are encountered (for example, at the brittle-plastic transition). Our proposed mechanism is especially relevant at the lithosphere-asthenosphere boundary, where olivine reaches the glass transition temperature, triggering a decrease in its viscosity and thus promoting grain-boundary sliding.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000626921700014 Publication Date 2021-03-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 40.137 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 40.137
Call Number UA @ admin @ c:irua:176656 Serial 6738
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Author Raymenants, E.; Bultynck, O.; Wan, D.; Devolder, T.; Garello, K.; Souriau, L.; Thiam, A.; Tsvetanova, D.; Canvel, Y.; Nikonov, D.E.; Young, I.A.; Heyns, M.; Sorée, B.; Asselberghs, I.; Radu, I.; Couet, S.; Nguyen, V.D.
Title Nanoscale domain wall devices with magnetic tunnel junction read and write Type A1 Journal article
Year 2021 Publication Nature Electronics Abbreviated Journal
Volume 4 Issue 6 Pages 392-398
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract (down) The manipulation of fast domain wall motion in magnetic nanostructures could form the basis of novel magnetic memory and logic devices. However, current approaches for reading and writing domain walls require external magnetic fields, or are based on conventional magnetic tunnel junctions (MTJs) that are not compatible with high-speed domain wall motion. Here we report domain wall devices based on perpendicular MTJs that offer electrical read and write, and fast domain wall motion via spin-orbit torque. The devices have a hybrid free layer design that consists of platinum/cobalt (Pt/Co) or a synthetic antiferromagnet (Pt/Co/Ru/Co) into the free layer of conventional MTJs. We show that our devices can achieve good tunnelling magnetoresistance readout and efficient spin-transfer torque writing that is comparable to current magnetic random-access memory technology, as well as domain wall depinning efficiency that is similar to stand-alone materials. We also show that a domain wall conduit based on a synthetic antiferromagnet offers the potential for reliable domain wall motion and faster write speed compared with a device based on Pt/Co. Domain wall devices based on perpendicular magnetic tunnel junctions with a hybrid free layer design can offer electrical read and write, and fast domain wall motion driven via spin-orbit torque.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000665011500005 Publication Date 2021-06-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2520-1131 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:179673 Serial 7003
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Author Godoi, R.H.M.; Potgieter-Vermaak, S.; Godoi, A.F.L.; Stranger, M.; Van Grieken, R.
Title Assessment of aerosol particles within the Rubens' House Museum in Antwerp, Belgium Type A1 Journal article
Year 2008 Publication X-ray spectrometry Abbreviated Journal
Volume 37 Issue 4 Pages 298-303
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The majority of researchers, conservators and curators recognise that atmospheric pollution is one of the major threats to works of art. In principle, all atmospheric particles, when deposited onto art objects can be considered harmful because of their potential in causing deterioration. Moreover, under certain conditions, particulate matter can induce and intensify surface damage, particularly because of its potential to serve as centre for moisture condensation and adsorbent of gaseous pollutants. To investigate the potential harm that these particles can cause, comprehensive characterisation of the particulate matter is necessary. Particulate matter was collected at the Rubens' House Museum in Antwerp, Belgium, where a unique exhibit of the paintings and living quarters of Peter Paul Rubens (1577-1640) are seen. Size segregated aerosol samples were collected for analyses of bulk and single particle elemental and molecular compositions. They were analysed by electron probe micro-analysis, utilising facilities for low-Z element determination, and by energy-dispersive x-ray fluorescence, to investigate the elemental composition of individual particles and bulk samples, and by micro Raman spectrometry, to elucidate the molecular composition. Results are interpreted separately and as a whole with the specific aim of identifying compounds that could contribute to the chemical reactions taking place on the surfaces of artefacts and which could potentially cause degradation of the objects.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000258670600004 Publication Date 2008-03-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0049-8246 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:69494 Serial 7499
Permanent link to this record
 

 
Author Buczyńska, A.J.; Krata, A.; Stranger, M.; Godoi, A.F.L.; Kontozova-Deutsch, V.; Bencs, L.; Naveau, I.; Roekens, E.; Van Grieken, R.
Title Atmospheric BTEX-concentrations in an area with intensive street traffic Type A1 Journal article
Year 2009 Publication Atmospheric environment : an international journal Abbreviated Journal
Volume 43 Issue 2 Pages 311-318
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The major threat to clean air in developed and industrializing countries is now posed by traffic emissions. The effects of traffic road modifications on the air quality are, however, rarely reported in the literature. The aim of this study was to determine the influence of the modernization and renovation of a traffic artery in the region of Mortsel (Antwerp, Belgium) on the concentration of volatile organic compounds such as: benzene, toluene, ethylbenzene and m-, p-, o-xylenes (BTEX). The original goal of the reconstruction works was to reduce the traffic lanes of one of the busiest streets in Antwerp, in order to discourage the road traffic and in consequence also to improve the air quality in this region. The average concentrations of BTEX before these works in 2003 were: 1.6, 7.0, 0.9, 2.3, and 0.9 ìg/m3, for benzene, toluene, ethylbenzene, m + p xylenes, and o-xylene, respectively. However, after the completion of the works, in 2005, they were slightly higher: 2.5, 9.5, 1.6, 3.4, and 1.3 ìg/m3, respectively. The scatter plots of benzene against toluene, ethylbenzene and xylenes in 2003 and 2005 showed very good correlations. This fact indicated that all of the measured compounds originated from the same source, namely the road traffic. Moreover, the data obtained from an air-monitoring station at less than 6 km distance from the sampling site (operated by the Flemish Environment Agency, and located in Borgerhout, Antwerp), confirmed the lack of influence of background concentrations of BTEX. The obtained results led to the conclusion that the reduction of the number of traffic lanes had apparently increased the traffic jams and also increased the emission from cars. Therefore, these modernization works had even a negative impact on the local concentration of traffic-related pollutants as BTEX.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000262956500011 Publication Date 2008-10-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1352-2310 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:72925 Serial 7518
Permanent link to this record
 

 
Author Čevik, U.; Damla, N.; Van Grieken, R.; Vefa Akpinar, M.
Title Chemical composition of building materials used in Turkey Type A1 Journal article
Year 2011 Publication Construction and building materials Abbreviated Journal
Volume 25 Issue 4 Pages 1546-1552
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The main goal of this work was to determine the chemical composition of building materials used in Turkey by utilizing energy dispersive X-ray fluorescence (EDXRF) spectrometry. Gas concrete, cement, sand, bricks, roofing tiles, marble, lime and gypsum materials were selected as building materials for this research. The chemical contents and their trace concentrations of the selected samples were determined. The most abundant oxides measured were generally SiO2, Al2O3, CaO, MgO, Fe2O3, K2O and SO3 for all samples. While the main chemical component of gas concrete, cement, sand and marble samples were SiO2 and CaO, brick and roofing tile mainly consisted of SiO2 and Al2O3. CaO and SO3 were major component of lime and gypsum samples, respectively. For U and Th concentrations in the samples, activities of 226Ra and 232Th were measured by utilizing gamma spectrometry. ANOVA and Pearson correlation analyses were performed on the studied data for statistical analysis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000287379300007 Publication Date 2010-09-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0950-0618 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:86448 Serial 7653
Permanent link to this record
 

 
Author Saiz-Jimenez, C.; Garcia-Rowe, J.; Garcia Del Cura, M.A.; Ortega-Camvo, J.J.; Roekens, E.; Van Grieken, R.
Title Endolithic cyanobacteria in Maastricht limestone Type A1 Journal article
Year 1990 Publication The science of the total environment Abbreviated Journal
Volume 94 Issue 3 Pages 209-220
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract (down) The Maastricht limestone used for the construction of the 14th century O.L. Basilica in Tongeren, Belgium, is a light yellowish, porous, soft rock of the Late Cretaceous age. The limestone has a high carbonate content (> 95%); quartz and glauconite occur rarely. On the north side of the building, there is extensive growth of epilithic algae. On the south side, an assemblage of organisms was observed beneath the abiotic surface. This community, developed as a green layer 1 mm below the surface, is dominated by cyanobacteria. A moss was also present. The organisms were studied by transmitted light, phase contrast and scanning electron microscopy, and isolated in cultures. The cyanobacteria belong to the genera Synechococcus and Chroococcidiopsis, and the moss was identified as Tortula muralis Hedw. The organic matter present in the green layer was characterized in terms of molecular components using analytical pyrolysis. Pyrolysis products from polysaccharides and proteins, and evaporation/pyrolysis products from lipids, comprise the vast majority of identified compounds. The identification of specific biomarkers such as 7-methylheptadecane is further evidence of the presence of cyanobacteria. Phytenes and phytadienes are indicative of phototrophic organisms, as they are pyrolysis products from chlorophylls.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos A1990DF51800004 Publication Date 2003-09-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0048-9697; 1879-1026 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:116654 Serial 7902
Permanent link to this record
 

 
Author Cong, S.
Title Numerical study on low-pressure hollow cathode argon arc plasma Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages XIX, 126 p.
Keywords Doctoral thesis; Philosophy; Educational sciences; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract (down) The low-pressure hollow cathode discharge made of a hollow circular tube and an anode is a type of simple structure discharge system. In particular, under the arc discharge mode, hollow cathodes have high plasma density and energy density with a wide range of adaptability of pressure and current. Low-pressure hollow cathode arc (HCA) discharges have been widely used as plasma sources in various fields such as manufacturing, vacuum welding, and aerospace since the 1960s. Despite the early experimental and applied researches on low-pressure HCA discharges, the basic theoretical study was relatively lagged much behind, resulting in many unanswered questions, such as the optimal discharge operating parameters, the power deposition inside the cathode, the causes of plasma instability, and how to effectively reduce cathode erosion and so on. Due to the special discharge structure of the hollow cathode, it is difficult to make an accurate experimental diagnosis, so a reasonable numerical simulation is an effective study method. However, up to now, there is still a lack of complete and effective numerical models which can evaluate various physical fields in the low-pressure hollow cathode discharges. To address the above problems and difficulties, a comprehensive and self-consistent 2D multi-physical coupling numerical model based on a commercial program of finite element method, the COMSOL Multiphysics, was provided in this paper. The model involves plasma transport, arc flow and heat transfer, and cathode thermal equilibrium, and can consider the effect of an applied magnetic field. The processes of secondary electron emission, thermal-field electron emission, ions and backflow high-energy electrons bombardment, and thermal radiation from the cathode surface are considered in the cathode thermal equilibrium process. Based on the above background, this paper works from the following aspects: In Chapter 1, the basic concepts of low-pressure HCA discharge including the hollow cathode effect, the basic characteristics, and operation modes were introduced firstly; Secondly, the application fields, development history, and overseas and domestic research status of hollow cathode discharge were reviewed; finally, the problems were presented and the research background was explained, and the research purpose of this paper was clarified. In Chapter 2, a complete and self-consistent numerical model of low-pressure hollow cathode discharge was proposed based on the fundamental theory and assumptions, and the set of control equations and boundary conditions in the model were elaborated. In addition, the electron energy distribution function, the collision processes, the solving tools of this model, and calculation schemes were introduced in detail. Finally, a validation example was given to test the rationality and applicability of the numerical model. In Chapter 3, the fundamental plasma properties of low-pressure hollow cathode arcs were investigated. Firstly, the ion Joule heating effect was studied. The results showed that the temperature distributions of the arc and cathode are only able to approach the experimental measurements after considering the ion Joule heating, which shows that the Joule heating of ions is crucial for the heating of the arc plasma. Secondly, by comparing the radial distribution of electron and ion density inside the cathode, the structure of the cathode sheath could be simulated well using this model. Finally, it was shown that the thermal radiation from the cathode surface is an important cooling mechanism of the cathode and only under higher surface emissivity can balance the larger heat flow given by the plasma to the cathode, and the temperature distribution of the cathode shows a non-monotonic increasing trend and is consistent with the profile of experimental measurement so that the so-called active zone is formed. In Chapter 4, the power deposition in the low-pressure HCA was studied in simulation. Two main aspects were considered: the power deposition into particles (both electrons and heavy particles) and the power deposition onto the cathode. It was found that the deposited power into particles increases with the rise of discharge current, but there is no effect on the total power deposition onto the cathode. In high-density plasmas, Coulomb collisions between electrons and ions also become very important, especially since a portion of the deposition energy on heavy particles comes mainly from the energy transfer from electrons to ions. It was also found that regardless of external parameters, half of the power deposition onto the cathode always comes from the particle contribution, while the other half is the net contribution of heat transfer and cathode radiation. The HCA model also allows the simulation of multiple discharge modes for low-pressure HCA discharges over a wide range of gas flow rates. It was also shown that the discharge operating conditions and the external magnetic field can change the distribution of the particle flow on the cathode wall. In Chapter 5, the ion sputtering erosion process on the cathode was simulated by coupling the HCA numerical model with the moving grid technique. The results showed that the ion sputtering erosion on the cathode depends on the ion flux and the plasma potential near the cathode wall and that their distribution and magnitude jointly determine the erosion morphology of the cathode. It was also found that the location of the most severe erosion on the cathode is located in the region of the densest ion flux on the cathode wall, rather than in the longitudinal correspondence with the central region of the internal positive column (IPC). The external magnetic fields can mitigate the cathode erosion and reduce the erosion depth, but stronger magnetic fields lead to a concentration of current density at the cathode tip, which can enhance erosion slightly at the cathode outlet end. Finally, the conclusions and innovation highlights were summarized, and prospects for future work were discussed.
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:178725 Serial 8323
Permanent link to this record
 

 
Author Shi, P.; Liu, M.; Yu, X.; Gielis, J.; Ratkowsky, D.A.
Title Proportional relationship between leaf area and the product of leaf length and width of four types of special leaf shapes Type A1 Journal article
Year 2019 Publication Forests (19994907) Abbreviated Journal
Volume 10 Issue 2 Pages 178
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The leaf area, as an important leaf functional trait, is thought to be related to leaf length and width. Our recent study showed that the Montgomery equation, which assumes that leaf area is proportional to the product of leaf length and width, applied to different leaf shapes, and the coefficient of proportionality (namely the Montgomery parameter) range from 1/2 to π/4. However, no relevant geometrical evidence has previously been provided to support the above findings. Here, four types of representative leaf shapes (the elliptical, sectorial, linear, and triangular shapes) were studied. We derived the range of the estimate of the Montgomery parameter for every type. For the elliptical and triangular leaf shapes, the estimates are π/4 and 1/2, respectively; for the linear leaf shape, especially for the plants of Poaceae that can be described by the simplified Gielis equation, the estimate ranges from 0.6795 to π/4; for the sectorial leaf shape, the estimate ranges from 1/2 to π/4. The estimates based on the observations of actual leaves support the above theoretical results. The results obtained here show that the coefficient of proportionality of leaf area versus the product of leaf length and width only varies in a small range, maintaining the allometric relationship for leaf area and thereby suggesting that the proportional relationship between leaf area and the product of leaf length and width broadly remains stable during leaf evolution.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000460744000102 Publication Date 2019-02-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1999-4907 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:157200 Serial 8427
Permanent link to this record
 

 
Author De Bock, A.; Belmans, B.; Vanlanduit, S.; Blom, J.; Alvarado Alvarado, A.A.; Audenaert, A.
Title A review on the leaf area index (LAI) in vertical greening systems Type A1 Journal article
Year 2023 Publication Building and environment Abbreviated Journal
Volume 229 Issue Pages 109926-14
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Sustainable Pavements and Asphalt Research (SuPAR); Energy and Materials in Infrastructure and Buildings
Abstract (down) The leaf area index (LAI) is a key dynamic parameter in Vertical Greening Systems (VGS). It quantifies the total amount of leaf area in the canopy and largely determines the extent of co-benefits of VGS. Whereas many studies on VGS discuss the importance of the LAI, only few elaborate on the parameter itself, how it is determined and what the current limitations are in VGS. Moreover, although there is scientific consensus on the importance of LAI in VGS, specific non-destructive monitoring techniques for continuous LAI monitoring appear to be absent, which results in limited overall data on the LAI of VGS under different spatial and temporal conditions and problems in quantifying the benefits of VGS in practice. To fill these gaps, this paper specifically focuses on the LAI of VGS and its monitoring techniques. An overview of existing LAI monitoring techniques in the field of VGS is presented. To arrive at dedicated techniques, this is complemented by a thorough analysis of LAI monitoring techniques used in other research fields, e.g. agriculture and forestry. It is established that two indirect techniques for LAI monitoring are currently available in the VGS sector, but a proper standardized sampling methodology currently lacks. Monitoring techniques used in other sectors offer opportunities for developing dedicated monitoring methods for VGS, but require further research due to the specific features of VGS systems. Furthermore, guidelines are proposed for a more standardized LAI determination of reporting of LAI values in VGS.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000950866100001 Publication Date 2022-12-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0360-1323 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.4 Times cited Open Access
Notes Approved Most recent IF: 7.4; 2023 IF: 4.053
Call Number UA @ admin @ c:irua:194575 Serial 9085
Permanent link to this record
 

 
Author Beames, A.; Broekx, S.; Heijungs, R.; Lookman, R.; Boonen, K.; Van Geert, Y.; Dendoncker, K.; Seuntjens, P.
Title Accounting for land-use efficiency and temporal variations between brownfield remediation alternatives in life-cycle assessment Type A1 Journal article
Year 2015 Publication Journal of cleaner production Abbreviated Journal
Volume 101 Issue Pages 109-117
Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The latest life-cycle assessment methods account for land use, due to the production, use and disposal of products and services, in terms of ecosystem damage. The process of brownfield remediation converts otherwise idle urban space into productive space. The value to ecosystems in this context is of course limited since the brownfield site remains urban. When evaluating brownfield remediation technologies, the availability of space on-site is dependent on the duration of time required by the remediation technology to reach the remediation target. Remediation technology alternatives tend to vary largely in terms of duration. Comparative life-cycle assessments of remediation technologies, to date, present the large variations between alternatives in terms of remediation duration but do not translate this into an impact or parameter. The restored subsurface zone is often defined as a functional unit, when in fact the surface area is the resource restored by the remediation service. The economic benefits of making land resources available are particularly important considerations in the context of brownfield remediation. The research proposes an innovative impact assessment approach that allows land to be considered as a finite resource. The method is applied in a comparative life-cycle assessment of two potential remediation scenarios for an idle brownfield in the Brussels region of Belgium. The results show that there is a trade-off between greenhouse gas emissions and land availability and that both are largely dependent on the efficiency of the contaminant extraction mechanism. The results also raise the question as to whether the economic valuation of land, like precious metals and fossil fuels, provides an accurate reflection of the true value of the resource. Considering land as a resource at the midpoint level is also relevant in other urban contexts where competition exists between different land-uses, where urban sprawl is detrimental to undeveloped areas and where urban intensification is a policy objective. (C) 2015 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000356988200010 Publication Date 2015-04-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-6526 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:127010 Serial 7412
Permanent link to this record
 

 
Author Wang, L.; Ratkowsky, D.A.; Gielis, J.; Ricci, P.E.; Shi, P.
Title Effects of the numerical values of the parameters in the Gielis equation on its geometries Type A1 Journal article
Year 2022 Publication Symmetry Abbreviated Journal Symmetry-Basel
Volume 14 Issue 12 Pages 2475-12
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract (down) The Lamé curve is an extension of an ellipse, the latter being a special case. Dr. Johan Gielis further extended the Lamé curve in the polar coordinate system by introducing additional parameters (n1, n2, n3; m): rφ=1Acosm4φn2+1Bsinm4φn3−1/n1, which can be applied to model natural geometries. Here, r is the polar radius corresponding to the polar angle φ; A, B, n1, n2 and n3 are parameters to be estimated; m is the positive real number that determines the number of angles of the Gielis curve. Most prior studies on the Gielis equation focused mainly on its applications. However, the Gielis equation can also generate a large number of shapes that are rotationally symmetric and axisymmetric when A = B and n2 = n3, interrelated with the parameter m, with the parameters n1 and n2 determining the shapes of the curves. In this paper, we prove the relationship between m and the rotational symmetry and axial symmetry of the Gielis curve from a theoretical point of view with the condition A = B, n2 = n3. We also set n1 and n2 to take negative real numbers rather than only taking positive real numbers, then classify the curves based on extremal properties of r(φ) at φ = 0, π/m when n1 and n2 are in different intervals, and analyze how n1, n2 precisely affect the shapes of Gielis curves.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000904525700001 Publication Date 2022-11-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2073-8994 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
Call Number UA @ admin @ c:irua:191860 Serial 7301
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Author Li, C.-F.; Zhao, K.; Liao, X.; Hu, Z.-Y.; Zhang, L.; Zhao, Y.; Mu, S.; Li, Y.; Li, Y.; Van Tendeloo, G.; Sun, C.
Title Interface cation migration kinetics induced oxygen release heterogeneity in layered lithium cathodes Type A1 Journal article
Year 2021 Publication Energy Storage Materials Abbreviated Journal
Volume 36 Issue Pages 115-122
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (down) The irreversible release of the lattice oxygen in layered cathodes is one of the major degradation mechanisms of lithium ion batteries, which accounts for a number of battery failures including the voltage/capacity fade, loss of cation ions and detachment of the primary particles, etc. Oxygen release is generally attributed to the stepwise thermodynamic controlled phase transitions from the layered to spinel and rock salt phases. Here, we report a strong kinetic effect from the mobility of cation ions, whose migration barrier can be significantly modulated by the phase epitaxy at the degrading interface. It ends up with a clear oxygen release heterogeneity and completely different reaction pathways between the thin and thick areas, as well as the interparticle valence boundaries, both of which widely exist in the mainstream cathode design with the secondary agglomerates. This work unveils the origin of the heterogenous oxygen release in the layered cathodes. It also sheds light on the rational design of cathode materials with enhanced oxygen stability by suppressing the cation migration.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000620584300009 Publication Date 2020-12-24
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:176654 Serial 6730
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