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Author Balashova, I.O.; Tolbin, A.Y.; Tarakanov, P.A.; Krot, A.R.; Fedorova, K., V; Sergeeva, I.A.; Trashin, S.A.; De Wael, K.; Pushkarev, V.E.; Koifman, M.O.; Ponomarev, G., V.
Title A covalently linked dyad based on zinc phthalocyanine and methylpheophorbide α : synthetic and physicochemical study Type A1 Journal article
Year 2021 Publication Macroheterocycles Abbreviated Journal
Volume 14 Issue 1 Pages (up) 40-50
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The first covalently linked conjugate of metal phthalocyaninate and chlorin e(6) derivative has been obtained by transesterification of alpha-ketomethyl ester in methylpheophorbide a with zinc(II) 2-(2-hydroxymethylbenzyloxy)-9(10),16(17),23(24)-tri-tert-butylphthalocyaninate under mild conditions. The dyad exhibits a panchromatic nature revealing both the phthalocyanine and pheophorbide derived bands in the UV-Vis absorption spectrum. The H-1 NMR spectroscopy data combined with theoretical calculations indicate the presence of spatial intramolecular interactions between the phthalocyanine, pheophorbide and spacer fragments of the dyad allowing to forecast its enhanced nonlinear optical properties, as well as the characteristic energy transfer from the excited pheophorbide subunit to the phthalocyanine core. Indeed, when excited in the UV-Vis range, the conjugate shows red fluorescence with the spectral maximum at 686 nm, which is close to the one of the initial zinc phthalocyaninate. Furthermore, the dyad effectively generates singlet oxygen and, in the presence of polyvinylpyrrolidone (PVP) as biocompatible solubilizer, forms stable micellar saline solutions with the particles ranged in size between 40 and 100 nm. These nanoparticles represent promising third-generation photosensitizing systems for application in theranostics.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000659682000003 Publication Date 2021-06-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access OpenAccess
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:179196 Serial 7386
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Author Conti, S.; Saberi-Pouya, S.; Perali, A.; Virgilio, M.; Peeters, F.M.; Hamilton, A.R.; Scappucci, G.; Neilson, D.
Title Electron-hole superfluidity in strained Si/Ge type II heterojunctions Type A1 Journal article
Year 2021 Publication npj Quantum Materials Abbreviated Journal
Volume 6 Issue 1 Pages (up) 41
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Excitons are promising candidates for generating superfluidity and Bose-Einstein condensation (BEC) in solid-state devices, but an enabling material platform with in-built band structure advantages and scaling compatibility with industrial semiconductor technology is lacking. Here we predict that spatially indirect excitons in a lattice-matched strained Si/Ge bilayer embedded into a germanium-rich SiGe crystal would lead to observable mass-imbalanced electron-hole superfluidity and BEC. Holes would be confined in a compressively strained Ge quantum well and electrons in a lattice-matched tensile strained Si quantum well. We envision a device architecture that does not require an insulating barrier at the Si/Ge interface, since this interface offers a type II band alignment. Thus the electrons and holes can be kept very close but strictly separate, strengthening the electron-hole pairing attraction while preventing fast electron-hole recombination. The band alignment also allows a one-step procedure for making independent contacts to the electron and hole layers, overcoming a significant obstacle to device fabrication. We predict superfluidity at experimentally accessible temperatures of a few Kelvin and carrier densities up to similar to 6 x 10(10) cm(-2), while the large imbalance of the electron and hole effective masses can lead to exotic superfluid phases.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000642904200001 Publication Date 2021-04-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2397-4648 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 9 Open Access OpenAccess
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:178226 Serial 6984
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Author Shi, P.; Yu, K.; Niinemets, Ü.; Gielis, J.
Title Can leaf shape be represented by the ratio of leaf width to length? Evidence from nine species of Magnolia and Michelia (Magnoliaceae) Type A1 Journal article
Year 2021 Publication Forests Abbreviated Journal Forests
Volume 12 Issue 1 Pages (up) 41
Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Abstract Leaf shape is closely related to economics of leaf support and leaf functions, including light interception, water use, and CO2 uptake, so correct quantification of leaf shape is helpful for studies of leaf structure/function relationships. There are some extant indices for quantifying leaf shape, including the leaf width/length ratio (W/L), leaf shape fractal dimension (FD), leaf dissection index, leaf roundness index, standardized bilateral symmetrical index, etc. W/L ratio is the simplest to calculate, and recent studies have shown the importance of the W/L ratio in explaining the scaling exponent of leaf dry mass vs. leaf surface area and that of leaf surface area vs. leaf length. Nevertheless, whether the W/L ratio could reflect sufficient geometrical information of leaf shape has been not tested. The FD might be the most accurate measure for the complexity of leaf shape because it can characterize the extent of the self-similarity and other planar geometrical features of leaf shape. However, it is unknown how strongly different indices of leaf shape complexity correlate with each other, especially whether W/L ratio and FD are highly correlated. In this study, the leaves of nine Magnoliaceae species (>140 leaves for each species) were chosen for the study. We calculated the FD value for each leaf using the box-counting approach, and measured leaf fresh mass, surface area, perimeter, length, and width. We found that FD is significantly correlated to the W/L ratio and leaf length. However, the correlation between FD and the W/L ratio was far stronger than that between FD and leaf length for each of the nine species. There were no strong correlations between FD and other leaf characteristics, including leaf area, ratio of leaf perimeter to area, fresh mass, ratio of leaf fresh mass to area, and leaf roundness index. Given the strong correlation between FD and W/L, we suggest that the simpler index, W/L ratio, can provide sufficient information of leaf shape for similarly-shaped leaves. Future studies are needed to characterize the relationships among FD and W/L in leaves with strongly varying shape, e.g., in highly dissected leaves.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000611074700001 Publication Date 2020-12-31
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 1.951 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 1.951
Call Number UA @ admin @ c:irua:174473 Serial 7572
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Author Tessema, G.A.; van der Borg, J.; Minale, A.S.; Van Rompaey, A.; Adgo, E.; Nyssen, J.; Asrese, K.; Van Passel, S.; Poesen, J.
Title Inventory and assessment of geosites for geotourism development in the eastern and southeastern Lake Tana Region, Ethiopia Type A1 Journal article
Year 2021 Publication Geoheritage Abbreviated Journal Geoheritage
Volume 13 Issue 2 Pages (up) 43
Keywords A1 Journal article; Engineering Management (ENM)
Abstract Geotourism is a niche form of sustainable tourism that focuses on the geological and geomorphological features of an area, and the associated culture and biodiversity. Geosites are important resources for geotourism development. The eastern and southeastern Lake Tana region in Ethiopia has several geosites with a potential for geotourism development. Despite the diversity of potential geosites and the strategic location of the area in the Northern Tourist Circuit of Ethiopia, only a few attractions such as Lake Tana and the Blue Nile Falls are currently being visited. The objective of this paper is twofold: to inventory geosites in the eastern and southeastern Lake Tana region and assess their potential for geotourism development; and to propose a geosite inventory and assessment methodology for geotourism purposes with adaptations from previous studies. Several studies were reviewed and finally nine of them used as the main references to prepare the criteria, indicators, and sub-indicators for this study. The indicators used for assessing the potential of geosites relate to scientific, educational, scenic, recreational, protection, functional, and ecological values. This research presents the first inventory of geosites in the Lake Tana basin. A first list of 120 geosites has been inventoried. Further screening and clustering resulted in 61 geosites, of which 17 are viewpoints. Among the major geosites are waterfalls, a lake with islands and island monasteries, a flood plain, caves and cave churches, lava tubes, a mountain (shield volcano), volcanic plugs, volcanic cones, rock-hewn churches, and viewpoints. Quantitative assessment of the geotouristic potential of these geosites revealed that clustered (complex area) geosites received higher scientific, scenic, and recreational value scores.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000646574000002 Publication Date 2021-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1867-2477 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.472 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 1.472
Call Number UA @ admin @ c:irua:178962 Serial 6933
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Author McLachlan, G.; Majdak, P.; Reijniers, J.; Peremans, H.
Title Towards modelling active sound localisation based on Bayesian inference in a static environment Type A1 Journal article
Year 2021 Publication Acta Acustica Abbreviated Journal
Volume 5 Issue Pages (up) 45
Keywords A1 Journal article; Engineering Management (ENM); Condensed Matter Theory (CMT)
Abstract Over the decades, Bayesian statistical inference has become a staple technique for modelling human multisensory perception. Many studies have successfully shown how sensory and prior information can be combined to optimally interpret our environment. Because of the multiple sound localisation cues available in the binaural signal, sound localisation models based on Bayesian inference are a promising way of explaining behavioural human data. An interesting aspect is the consideration of dynamic localisation cues obtained through self-motion. Here we provide a review of the recent developments in modelling dynamic sound localisation with a particular focus on Bayesian inference. Further, we describe a theoretical Bayesian framework capable to model dynamic and active listening situations in humans in a static auditory environment. In order to demonstrate its potential in future implementations, we provide results from two examples of simplified versions of that framework.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000709050000001 Publication Date 2021-10-21
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:182453 Serial 7035
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Author Tiwari, S.; Van de Put, M.L.; Sorée, B.; Vandenberghe, W.G.
Title Magnetic order and critical temperature of substitutionally doped transition metal dichalcogenide monolayers Type A1 Journal article
Year 2021 Publication npj 2D Materials and Applications Abbreviated Journal
Volume 5 Issue 1 Pages (up) 54
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract Using first-principles calculations, we investigate the magnetic order in two-dimensional (2D) transition-metal-dichalcogenide (TMD) monolayers: MoS2, MoSe2, MoTe2, WSe2, and WS2 substitutionally doped with period four transition-metals (Ti, V, Cr, Mn, Fe, Co, Ni). We uncover five distinct magnetically ordered states among the 35 distinct TMD-dopant pairs: the non-magnetic (NM), the ferromagnetic with out-of-plane spin polarization (Z FM), the out-of-plane polarized clustered FMs (clustered Z FM), the in-plane polarized FMs (X-Y FM), and the anti-ferromagnetic (AFM) state. Ni and Ti dopants result in an NM state for all considered TMDs, while Cr dopants result in an anti-ferromagnetically ordered state for all the TMDs. Most remarkably, we find that Fe, Mn, Co, and V result in an FM ordered state for all the TMDs, except for MoTe2. Finally, we show that V-doped MoSe2 and WSe2, and Mn-doped MoS2, are the most suitable candidates for realizing a room-temperature FM at a 16-18% atomic substitution.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000650635200004 Publication Date 2021-05-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2397-7132 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:179063 Serial 7001
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Author Zheng, Y.-R.; Vernieres, J.; Wang, Z.; Zhang, K.; Hochfilzer, D.; Krempl, K.; Liao, T.-W.; Presel, F.; Altantzis, T.; Fatermans, J.; Scott, S.B.; Secher, N.M.; Moon, C.; Liu, P.; Bals, S.; Van Aert, S.; Cao, A.; Anand, M.; Nørskov, J.K.; Kibsgaard, J.; Chorkendorff, I.
Title Monitoring oxygen production on mass-selected iridium–tantalum oxide electrocatalysts Type A1 Journal article
Year 2021 Publication Nature Energy Abbreviated Journal Nat Energy
Volume Issue Pages (up)
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Abstract Development of low-cost and high-performance oxygen evolution reaction catalysts is key to implementing polymer electrolyte membrane water electrolyzers for hydrogen production. Iridium-based oxides are the state-of-the-art acidic oxygen evolution reactio catalysts but still suffer from inadequate activity and stability, and iridium's scarcity motivates the discovery of catalysts with lower iridium loadings. Here we report a mass-selected iridium-tantalum oxide catalyst prepared by a magnetron-based cluster source with considerably reduced noble-metal loadings beyond a commercial IrO2 catalyst. A sensitive electrochemistry/mass-spectrometry instrument coupled with isotope labelling was employed to investigate the oxygen production rate under dynamic operating conditions to account for the occurrence of side reactions and quantify the number of surface active sites. Iridium-tantalum oxide nanoparticles smaller than 2 nm exhibit a mass activity of 1.2 ± 0.5 kA “g” _“Ir” ^“-1” and a turnover frequency of 2.3 ± 0.9 s-1 at 320 mV overpotential, which are two and four times higher than those of mass-selected IrO2, respectively. Density functional theory calculations reveal that special iridium coordinations and the lowered aqueous decomposition free energy might be responsible for the enhanced performance.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000728458000001 Publication Date 2021-12-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2058-7546 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 95 Open Access OpenAccess
Notes Y.-R.Z. and Z.W acknowledge funding from the Toyota Research Institute. This project has received funding from VILLUM FONDEN (grant no. 9455) and the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grants no. 741860-CLUNATRA, no. 815128−REALNANO and no. 770887−PICOMETRICS). S.B. and S.V.A. acknowledge funding from the Research Foundation Flanders (FWO, G026718N and G050218N). T.A. acknowledges the University of Antwerp Research Fund (BOF). STEM measurements were supported by the European Union's Horizon 2020 Research Infrastructure-Integrating Activities for Advanced Communities under grant agreement No 823717 – ESTEEM3.; sygmaSB Approved Most recent IF: NA
Call Number EMAT @ emat @c:irua:184794 Serial 6903
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Author Gupta, A.; Baron, G.V.; Perreault, P.; Lenaerts, S.; Ciocarlan, R.-G.; Cool, P.; Mileo, P.G.M.; Rogge, S.; Van Speybroeck, V.; Watson, G.; Van Der Voort, P.; Houlleberghs, M.; Breynaert, E.; Martens, J.; Denayer, J.F.M.
Title Hydrogen clathrates : next generation hydrogen storage materials Type A1 Journal article
Year 2021 Publication Energy Storage Materials Abbreviated Journal
Volume 41 Issue Pages (up) 69-107
Keywords A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA); Sustainable Energy, Air and Water Technology (DuEL)
Abstract Extensive research has been carried on the molecular adsorption in high surface area materials such as carbonaceous materials and MOFs as well as atomic bonded hydrogen in metals and alloys. Clathrates stand among the ones to be recently suggested for hydrogen storage. Although, the simulations predict lower capacity than the expected by the DOE norms, the additional benefits of clathrates such as low production and operational cost, fully reversible reaction, environmentally benign nature, low risk of flammability make them one of the most promising materials to be explored in the next decade. The inherent ability to tailor the properties of clathrates using techniques such as addition of promoter molecules, use of porous supports and formation of novel reverse micelles morphology provide immense scope customisation and growth. As rapidly evolving materials, clathrates promise to get as close as possible in the search of “holy grail” of hydrogen storage. This review aims to provide the audience with the background of the current developments in the solid-state hydrogen storage materials, with a special focus on the hydrogen clathrates. The in-depth analysis of the hydrogen clathrates will be provided beginning from their discovery, various additives utilised to enhance their thermodynamic and kinetic properties, challenges in the characterisation of hydrogen in clathrates, theoretical developments to justify the experimental findings and the upscaling opportunities presented by this system. The review will present state of the art in the field and also provide a global picture for the path forward.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000685118300009 Publication Date 2021-06-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2405-8297 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:178744 Serial 8045
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Author Khalilov, U.; Neyts, E.C.
Title Mechanisms of selective nanocarbon synthesis inside carbon nanotubes Type A1 Journal article
Year 2021 Publication Carbon Abbreviated Journal Carbon
Volume 171 Issue Pages (up) 72-78
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The possibility of confinement effects inside a carbon nanotube provides new application opportunities, e.g., growth of novel carbon nanostructures. However, the understanding the precise role of catalystfeedstock in the nanostructure synthesis is still elusive. In our simulation-based study, we investigate the Ni-catalyzed growth mechanism of encapsulated carbon nanostructures, viz. double-wall carbon nanotube and graphene nanoribbon, from carbon and hydrocarbon growth precursors, respectively. Specifically, we find that the tube and ribbon growth is determined by a catalyst-vs-feedstock competition effect. We compare our results, i.e., growth mechanism and structure morphology with all available theoretical and experimental data. Our calculations show that all encapsulated nanostructures contain metal (catalyst) atoms and such structures are less stable than their pure counterparts. Therefore, we study the purification mechanism of these structures. In general, this study opens a possible route to the controllable synthesis of tubular and planar carbon nanostructures for today’s nanotechnology.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000598371500009 Publication Date 2020-09-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0008-6223 ISBN Additional Links UA library record; WoS full record
Impact Factor 6.337 Times cited Open Access OpenAccess
Notes Fund of Scientific Research Flanders, 12M1318N ; Universiteit Antwerpen; Flemish Supercomputer Centre; Hercules Foundation; Flemish Government; The authors gratefully acknowledge the financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant number 12M1318N. The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Centre (VSC), funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA, Belgium. Approved Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:172459 Serial 6414
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Author de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
Title Efficient fitting algorithm Type H2 Book chapter
Year 2021 Publication Advances in imaging and electron physics T2 – Advances in imaging and electron physics Abbreviated Journal
Volume Issue Pages (up) 73-90
Keywords H2 Book chapter; Electron microscopy for materials research (EMAT)
Abstract An efficient model-based estimation algorithm is introduced to quantify the atomic column positions and intensities from atomic-resolution (scanning) transmission electron microscopy ((S)TEM) images. This algorithm uses the least squares estimator on image segments containing individual columns fully accounting for overlap between neighboring columns, enabling the analysis of a large field of view. To provide end-users with this well-established quantification method, a user friendly program, StatSTEM, is developed which is freely available under a GNU public license. In this chapter, this efficient algorithm is applied to three different nanostructures for which the analysis of a large field of view is required.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2021-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume 217 Series Issue Edition
ISSN ISBN 978-0-12-824607-8; 1076-5670 Additional Links UA library record
Impact Factor Times cited Open Access Not_Open_Access
Notes ERC Consolidator project funded by the European Union grant #770887 Picometrics Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:177528 Serial 6778
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Author Psilodimitrakopoulos, S.; Orekhov, A.; Mouchliadis, L.; Jannis, D.; Maragkakis, G.M.; Kourmoulakis, G.; Gauquelin, N.; Kioseoglou, G.; Verbeeck, J.; Stratakis, E.
Title Optical versus electron diffraction imaging of Twist-angle in 2D transition metal dichalcogenide bilayers Type A1 Journal article
Year 2021 Publication npj 2D Materials and Applications Abbreviated Journal
Volume 5 Issue 1 Pages (up) 77
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Atomically thin two-dimensional (2D) materials can be vertically stacked with van der Waals bonds, which enable interlayer coupling. In the particular case of transition metal dichalcogenide (TMD) bilayers, the relative direction between the two monolayers, coined as twist-angle, modifies the crystal symmetry and creates a superlattice with exciting properties. Here, we demonstrate an all-optical method for pixel-by-pixel mapping of the twist-angle with a resolution of 0.55(degrees), via polarization-resolved second harmonic generation (P-SHG) microscopy and we compare it with four-dimensional scanning transmission electron microscopy (4D STEM). It is found that the twist-angle imaging of WS2 bilayers, using the P-SHG technique is in excellent agreement with that obtained using electron diffraction. The main advantages of the optical approach are that the characterization is performed on the same substrate that the device is created on and that it is three orders of magnitude faster than the 4D STEM. We envisage that the optical P-SHG imaging could become the gold standard for the quality examination of TMD superlattice-based devices.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000694849200001 Publication Date 2021-09-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2397-7132 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 4 Open Access OpenAccess
Notes This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call European R & T Cooperation-Grant Act of Hellenic Institutions that have successfully participated in Joint Calls for Proposals of European Networks ERA NETS (National project code: GRAPH-EYE T8 Epsilon Rho Alpha 2-00009 and European code: 26632, FLAGERA). L.M., G.Ko. and G.Ki. acknowledge funding by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project No: HFRI-FM17-3034). GKi, S.P. and G.M.M. acknowledge funding from a research co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning 2014-2020” in the context of the project “Crystal quality control of two-dimensional materials and their heterostructures via imaging of their non-linear optical properties” (MIS 5050340)“. J.V acknowledges funding from FWO G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund, EU. J.V. and N.G. acknowledge funding from the European Union under the Horizon 2020 programme within a contract for Integrating Activities for Advanced Communities No 823717-ESTEEM3. J.V. N.G. and A.O. acknowledge funding through a GOA project ”Solarpaint" of the University of Antwerp. Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:181610 Serial 6877
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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 (up) 82-86
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract 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 Bizindavyi, J.; Verhulst, A.S.; Sorée, B.; Vandenberghe, W.G.
Title Thermodynamic equilibrium theory revealing increased hysteresis in ferroelectric field-effect transistors with free charge accumulation Type A1 Journal article
Year 2021 Publication Communications Physics Abbreviated Journal
Volume 4 Issue 1 Pages (up) 86
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract At the core of the theoretical framework of the ferroelectric field-effect transistor (FeFET) is the thermodynamic principle that one can determine the equilibrium behavior of ferroelectric (FERRO) systems using the appropriate thermodynamic potential. In literature, it is often implicitly assumed, without formal justification, that the Gibbs free energy is the appropriate potential and that the impact of free charge accumulation can be neglected. In this Article, we first formally demonstrate that the Grand Potential is the appropriate thermodynamic potential to analyze the equilibrium behavior of perfectly coherent and uniform FERRO-systems. We demonstrate that the Grand Potential only reduces to the Gibbs free energy for perfectly non-conductive FERRO-systems. Consequently, the Grand Potential is always required for free charge-conducting FERRO-systems. We demonstrate that free charge accumulation at the FERRO interface increases the hysteretic device characteristics. Lastly, a theoretical best-case upper limit for the interface defect density D-FI is identified. The ferroelectric field-effect transistor, which has attracted much attention for application as both a highly energy-efficient logic device and a non-volatile memory device, has often been studied within the framework of equilibrium thermodynamics. Here, the authors theoretically demonstrate the importance of utilizing the correct thermodynamic potential and investigate the impact of free charge accumulation on the equilibrium performance of ferroelectric-based systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000645913400001 Publication Date 2021-04-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2399-3650 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:179005 Serial 7031
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Author de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
Title Atom counting Type H2 Book chapter
Year 2021 Publication Advances in imaging and electron physics T2 – Advances in imaging and electron physics Abbreviated Journal
Volume Issue Pages (up) 91-144
Keywords H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
Abstract In this chapter, a statistical model-based method to count the number of atoms of monotype crystalline nanostructures from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images is discussed in detail together with a thorough study on the possibilities and inherent limitations. We show that this method can be applied to nanocrystals of arbitrary shape, size, and atom type. The validity of the atom-counting results is confirmed by means of detailed image simulations and it is shown that the high sensitivity of our method enables us to count atoms with single atom sensitivity.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2021-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume 217 Series Issue Edition
ISSN ISBN 978-0-12-824607-8; 1076-5670 Additional Links UA library record
Impact Factor Times cited Open Access Not_Open_Access
Notes ERC Consolidator project funded by the European Union grant #770887 Picometrics Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:177529 Serial 6776
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Author Du, K.
Title In situ TEM study on the manipulation of ferroelectrics Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) 91 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The strong correlated oxide systems attract a lot of attentions of scientists recently, the coexistence and interplay between various degrees of freedom, such as charge, spin and orbital, has been demonstrated to induce some fancy physical properties and phenomenon, including metal-insulator transition, high temperature superconductivity, colossal magnetoresistance. As a part of the strong correlated oxide systems, the ferroelectrics is abundant in both physical properties and application. First, if the electric dipole continuously rotating around a stable core then a topological structure is produced. If people could manipulate the topological structure and simultaneously observe the structure evolution, with external field applied on the topological structure, then it is very likely for such kind of ferroelectrics to be the next generation of storage, for it is reported to need low power input and produce high density of storage. In the other hand, in solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, such as ferroelectricity and ferromagnetism, antiferroelectricity and antiferromagnetism, but ferrielectricity and ferrimagnetism kept telling a disparate story in microscopic level. The claimed “ferrielectrics” in existing research is equivalent to ferroelectric ones, thus the findings of such a real irreducible solids would complete the last piece of the ferroelectrics family. While solving the above two questions remain challengeable: the size of topological structure is small (typically below 10 nm), general characterization methods are insufficient for such high demand on space resolution, not to mention manipulating and observing its dynamic behavior at an atomic level. Here, employing the spherical aberration corrected electron microscope, we applied external field (heating and bias) on ferroelectrics. Combined with high-end characterization methods including the high-angle annular dark field (HAADF-STEM) image, Electron Energy Loss Spectroscopy (EELS) and integrated differential phase contrast (iDPC), the dynamic evolution of ferroelectrics are observed and analyzed. The main findings of this paper could be concluded as listed here: (1) PbTiO3(001)// SrTiO3(001) is grown on DyScO3 and SrRuO3 by pusled laser deposition, the atomical EDS mapping results reveal that the interface between PTO and STO is atomically sharp. Increasing the thickness of PTO from 1 uc to 21 uc, the topological structure wihtin PTO layer would transform from a/c domain to wave, vortex and finally flux closure domain. The geometric phase analysis results (GPA) reveal that above topological structures are corresponding to various strain. (2) Combined with in-situ biasing holder, the electric bias was applied on polar vortex, and it evolved from vortex (0 V) to polar wave (2 V) and finally polar down (5 V). EELS analysis was performed and we find that negative charge is gathered at vortex core, which turns the Ti4+ to Ti3+ there. The oxygen vacancy at negative polarization surface and the negative charge at the positive polarization surface realized the polarization screening of polar down domain. (3) Through the atomic inspection and analysis on lattice structure of BaFe2Se3, the near ladders within single unit are found to be different in degree of tetramerization, thus leading to a residual polarization along the a-axis. The further in-situ heating and biasing experiment was conducted on BaFe2Se3, and the strong and weak ladders are proved to be independent for their behavior under external field. This findings distinguishes ferrielectrics from ferroelectrics in solids.
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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:179310 Serial 6842
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Author Esguerra, J.L.
Title Developing strategies for improved economic performance and reduced climate impact of landfill mining in Europe Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) xiv, 99 p.
Keywords Doctoral thesis; Economics; Engineering Management (ENM)
Abstract Landfill mining refers to the re-circulation of resources from the previously deposited wastes–integrating resource recovery with traditional site remediation. Several resources that can be recovered include scrap metals, combustibles, and inert materials. In addition, land can be recovered or landfill void space can be liberated for future wastes. At present, landfill mining is still an emerging concept with few project implementations. Consequently, the assessments of its economic and climate implications are case study-specific, limiting the understanding of its potential in a wider geographical scope. This thesis aims to assess the economic performance and climate impact of landfill mining in Europe towards the development of sound strategies for implementation. Different project setups are assessed in relation to varying factors at the site level such as waste composition and landfill settings, and at the system level such as policy and market conditions and background material and energy. In doing so, a factor-based method is developed and applied to generate multiple scenarios (531, 441 scenarios per project setup) and determine the underlying important factors and their interrelations that drive the results. Such understanding is used to develop and discuss strategies for improvement by addressing relevant questions for specific stakeholders, including project investors (i.e., which landfill sites to prioritize?), landfill mining practitioners (i.e., how to set up such projects?), and policymakers (i.e., which policy instruments can effectively support such projects?). Results show that landfill mining is preferable in terms of climate than economy. Possible improvements are shown by internalizing thermal treatment of combustibles and extending fines residue utilization as construction aggregates. In relation to the choice of project setups, preferable site and system-level conditions are identified in general but it is also discussed that the plausibility of finding such conditions may be difficult at present. This steers the development of more tailored strategies on what can be done now by the landfill practitioners in terms of setting up projects under current policy and market conditions in specific regions, or what can be done by the policymakers in terms of implementing various policy instruments that can drive such changes at the system level. Through this thesis, the future of landfill mining research is guided towards addressing key challenges and potential solutions for improvement. Furthermore, this thesis highlights the role of assessment as a tool for learning and guiding the development of emerging concepts such as landfill mining.
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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 978-91-7929-056-6 Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:183155 Serial 6920
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Author Xia, C.; Pedrazo-Tardajos, A.; Wang, D.; Meeldijk, J.D.; Gerritsen, H.C.; Bals, S.; de Donega, C.M.
Title Seeded growth combined with cation exchange for the synthesis of anisotropic Cu2-xS/ZnS, Cu2-xS, and CuInS2 nanorods Type A1 Journal article
Year 2021 Publication Chemistry of materials Abbreviated Journal
Volume 33 Issue 1 Pages (up) 102-116
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Colloidal copper(I) sulfide (Cu2-xS) nanocrystals (NCs) have attracted much attention for a wide range of applications because of their unique optoelectronic properties, driving scientists to explore the potential of using Cu2-xS NCs as seeds in the synthesis of heteronanocrystals to achieve new multifunctional materials. Herein, we developed a multistep synthesis strategy toward Cu2-xS/ZnS heteronanorods. The Janus-type Cu2-xS/ZnS heteronanorods are obtained by the injection of hexagonal high-chalcocite Cu2-xS seed NCs in a hot zinc oleate solution in the presence of suitable surfactants, 20 s after the injection of sulfur precursors. The Cu2-xS seed NCs undergo rapid aggregation and coalescence in the first few seconds after the injection, forming larger NCs that act as the effective seeds for heteronucleation and growth of ZnS. The ZnS heteronucleation occurs on a single (100) facet of the Cu2-xS seed NCs and is followed by fast anisotropic growth along a direction that is perpendicular to the c-axis, thus leading to Cu2-xS/ZnS Janus-type heteronanorods with a sharp heterointerface. Interestingly, the high-chalcocite crystal structure of the injected Cu2-xS seed NCs is preserved in the Cu2-xS segments of the heteronanorods because of the highthermodynamic stability of this Cu2-xS phase. The Cu2-xS/ZnS heteronanorods are subsequently converted into single-component Cu2-xS and CuInS2 nanorods by postsynthetic topotactic cation exchange. This work expands the possibilities for the rational synthesis of colloidal multicomponent heteronanorods by allowing the design principles of postsynthetic heteroepitaxial seeded growth and nanoscale cation exchange to be combined, yielding access to a plethora of multicomponent heteronanorods with diameters in the quantum confinement regime.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000610984700009 Publication Date 2020-12-28
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 10 Open Access OpenAccess
Notes C.X. acknowledges China Scholarship Council (CSC) for the financial support (grant number 201406330055). C.d.M.D. acknowledges funding from the European Commission for access to the EMAT facilities (grant number EUSMI E180900184). D.W. acknowledges an Individual Fellowship funded by the Marie Sklodowska-Curie Actions (MSCA) in Horizon 2020 program (grant 894254 SuprAtom). S.B. acknowledges support by means of the ERC Consolidator grant no. 815128 REALNANO. The authors thank Donglong Fu for XRD measurements.; sygma Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:176587 Serial 6732
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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 (up) 115-122
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract 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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Author Peeters, M.
Title The added value of Smart Product-Service Systems to real estate developments Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) 117 p.
Keywords Doctoral thesis; Economics; Engineering Management (ENM); Internet Data Lab (IDLab)
Abstract Socially responsible investments can be defined as an investment process that integrates ethical values and environmental protection, improving social conditions, and good governance into a traditional investment decision. This integration is mainly a consequence of the growing importance that investors give to environmental, social, and governance (ESG) criteria, resulting in more sustainable development. Also, in the real estate sector, increased attention is being paid to the contributions made to integrate economic, environmental, and social factors into decisions. The ESG framework looks closely at how companies are managed, and the impact related to their market value. The factors for investors’ focus are summarized as environmental, social, and governance. The term ESG was coined in a 2004 United Nations (UN) report titled “Who Cares Wins,” aimed at raising awareness regarding the importance of environmental, social, and corporate governance issues in financial markets. The ESG criteria’s specific purpose is to guide investors in recognizing sustainable investments without evaluating how sustainable the asset is or the investment value represented by sustainability. It is essential to underline that ESG does not take specific economic interests into account. The rationale behind this apparent gap is that investors investigate the economic aspects before investing. However, by not explicitly linking ESG and economic criteria, attractive investments are often misjudged and not implemented. For example, investments that only show their value in the longer term or indirectly influence value by achieving a higher retention rate among incumbent tenants, reducing or eliminating friction costs. A product–service system (PSS) refers to a market proposition (business model) that builds on a product’s traditional functionality by incorporating additional services. Although services are already offered, the PSS function is to link the service to a product. The service thereby supports the operation of the product and generates additional benefits. It encompasses the integrated solutions of products and services to satisfy customers' needs and generate maximum value. According to Sutanto et al., a PSS is designed to focus on sustainability characterized in three dimensions. 1. The economic dimension 2. The environmental dimension 3. The social dimension When discussing sustainability in this thesis, we use the criteria listed above related to socially responsible investments. The link between PSS and ESG is that a PSS focuses on creating a sustainable system, and ESG makes sustainability more visible to investors. Therefore, when PSS are recognized and implemented in buildings, they must be evaluated using ESG analysis methods. Product-Service Systems (PSS) try to find a way to offer services on top of a product. The product is essentially secondary to the result that is delivered from the services. For example, the modem (product) that a cable company provides will be of secondary importance to the connectivity (service). Alternatively, it will be less critical how heat is made (product) than the intended set point is achieved in the building. PSSs transform the supply of products into services. In doing so, the responsibility shifts from delivering a product (once only) to continuous service delivery. Therefore, it is in the best interest of the service provider to deliver the outcome of the service as efficiently (read: lowest cost) as possible. A direct consequence of this is that the service provider will want to use the product as efficiently as possible and as long as possible to reduce his costs. Therefore, the supplier will also want to recover and maximize the reuse of his product based on the same rationale. A positive impact on the environment and the used raw materials is thus to be expected. The whole process of servitization (transforming products into services) in real estate will positively impact the Economic, Environmental and Social factors. Therefore, demonstrating this proposition is the main objective of this thesis. Smart PSS is the same idea as Product-Service systems but in which the digitization of the services plays a key role. It will be shown that by digitizing services, a broader range can be offered. It will be demonstrated that products that provide services at the building level can, through their interconnectedness, also provide services to external systems (e.g. electricity grid, urban planning, mobility, ...). At the same time, digitizing the products and services will also underpin trust in the systems and allow for proper remuneration. In this PhD, different standard systems in a building, such as the reservation system, the water heater, or the fire detection system, are equipped with additional services. A PSS is often specifically designed to focus on economic, social, and environmental dimensions. These dimensions correspond to the investor’s examination as part of the ESG analysis before investing. As the PSS is often specifically designed to integrate sustainability, there is a close link between the sustainability performance of the PSS and the ESG criteria evaluated by the investor. Throughout the work, the owner is considered to be the user of the building. It is not the case that only an owner-user can generate cash flow. In essence, if they have sufficient rights to the underlying product, any building user can activate services that generate cash flow. In today's market, it is logical that this is viewed in the owner-user context as they will usually choose the products to be installed in larger technical installations. They may have previously used a PSS or choose to move to one. However, a building’s tenant could choose to lease out their meeting rooms if they are not contractually prohibited from doing so since, in practice, contracts have begun to prohibit certain services. For example, rental contracts that actively prohibit renting out a property through platforms such as Airbnb. Thus, the user’s function could potentially impact how the PSS is designed. This work does not explicitly explore the impact of this aspect. The owner-user is assumed throughout this manuscript. The second chapter describes the state of affairs concerning PSSs in a broad framework evolving towards focusing on the real estate sector. After which, in the second chapter, ESG and the link to real estate and how smart real estate (smart buildings) is missing from this evaluation are discussed in more detail. Chapter 3 shows from a fire alarm system, which was extended with an evacuation support system, the usefulness, and the risk of data. Further work was done to demonstrate the added value in terms of Economic, Environmental and Social factors of standard installations in buildings. In Chapter 4, a simple sanitary hot water boiler is extended with a service that allows controlling this boiler according to the status of the electricity grid (surplus or shortage of energy). The supply and demand of energy on the power grid must be equal at all times. By equipping a classic water heater (product) with additional intelligence (service), it becomes possible to adjust the energy use to the grid's needs. The grid operators are prepared to pay for this. This payment can be linked to different energy markets (long term market, spot market, ...). This study looked at the fee that would have to be paid when the adjustment of the energy use can be made instantaneously so that the fee must be settled according to the prices on the imbalance market. In chapter 5, we look at the impact of the service to rent out free spaces as co-working places on a broad market (external to the building), compared to a regular reservation system. By renting out unused workplaces on a broad market, the utilization of the existing patrimony will be higher. The demand for new square meters with the same function will decrease as the supply-demand curve changes, and so will the price. This makes it less interesting to build new buildings. Less construction of new buildings will result in fewer resources being used, which will positively affect the environment. In addition, fewer new buildings with an office function will leave more space for buildings with another function. Also, the city's infrastructure will be less burdened (roads, sewerage, electricity grid,...). In The Hague, the decreasing need for new square meters of office buildings can lead to more space for affordable housing, for which the city has a great need. Chapter 6 will frame the valuation of service as a real options method that gives an impetus to a general valuation methodology to value the flexibility that Smart PSS inherently has. Finally, this thesis demonstrates that (smart) PSSs impact real estate profitability, while positively influencing environmental and social factors. Further research and the limitations of the studies conducted are documented. This PhD concludes that Product-Service systems should break the silos between different stakeholders, resulting in a lower total cost of ownership of buildings in the longer term. This can only be achieved if the valuation of Product-Service systems is done correctly and is recognized by every stakeholder in the real estate process.
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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:183415 Serial 6912
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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 (up) XIX, 126 p.
Keywords Doctoral thesis; Philosophy; Educational sciences; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract 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.
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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
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Author Velazco Torrejón, A.
Title Alternative scan strategies for high resolution STEM imaging Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) 131 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract Currently, a large variety of materials are studied by transmission electron microscopy (TEM) as it offers the possibility to perform structural and elemental analysis at a local scale. Relatively recent advances in aberration correctors and electron sources allow the instrument to achieve atomic resolution. Along with these advances, a state-of-the-art technology has been reached in TEM. However, the instrument is far from being perfect and imperfections or external sources can make the interpretation of information troublesome. Environmental factors such as acoustic and mechanical vibrations, temperature fluctuations, etc., can induce sample drift and create image distortions. These distortions are enhanced in scanning operation because of the serial acquisition of the information, which are more apparent at atomic resolution as small field of views are imaged. In addition, scanning distortions are induced due to the finite time response of the scan coils. These types of distortions would reduce precision in atomic-scale strain analysis, for instance, in semiconductors. Most of the efforts to correct these distortions are focused on data processing techniques post-acquisition. Another limitation in TEM is beam damage effects. Beam damage arises because of the energy transferred to the sample in electron-sample interactions. In scanning TEM, at atomic resolution, the increased electron charge density (electron dose) carried on a sub-Å size electron probe may aggravate beam damage effects. Soft materials such as zeolites, organic, biological materials, etc., can be destroyed under irradiation limiting the amount of information that can be acquired. Current efforts to circumvent beam damage are mostly based on low electron dose acquisitions and data processing methods to maximize the signal at low dose conditions. In this thesis, a different approach is given to address drift and scanning distortions, as well as beam damage effects. Novel scan strategies are proposed for that purpose, which are shown to substantially overcome these issues compared to the standard scan method in TEM.
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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:180973 Serial 6852
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Author Zhao, H.; Li, C.-F.; Hu, Z.-Y.; Liu, J.; Li, Y.; Hu, J.; Van Tendeloo, G.; Chen, L.-H.; Su, B.-L.
Title Size effect of bifunctional gold in hierarchical titanium oxide-gold-cadmium sulfide with slow photon effect for unprecedented visible-light hydrogen production Type A1 Journal article
Year 2021 Publication Journal Of Colloid And Interface Science Abbreviated Journal J Colloid Interf Sci
Volume 604 Issue Pages (up) 131-139
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Gold nanoparticles (Au NPs) with surface plasmonic resonance (SPR) effect and excellent internal electron transfer ability have widely been combined with semiconductors for photocatalysis. However, the in-depth effects of Au NPs in multicomponent photocatalysts have not been completely understood. Herein, ternary titanium oxide-gold-cadmium sulfide (TiO2-Au-CdS, TAC) photocatalysts, based on hierarchical TiO2 inverse opal photonic crystal structure with different Au NPs sizes have been designed to reveal the SPR effect and internal electron transfer of Au NPs in the presence of slow photon effect. It appears that the SPR effect and internal electron transfer ability of Au NPs, depending on their sizes, play a synergistic effect on the photocatalytic enhancement. The ternary TAC-10 photocatalyst with – 10 nm Au NPs demonstrates an unprecedented hydrogen evolution rate of 47.6 mmolh-1g 1 under visible-light, demonstrating- 48% enhancement comparing to the sample without slow photon effect. In particular, a 9.83% apparent quantum yield under 450 nm monochromatic light is achieved for TAC-10. A model is proposed and finite-difference time-domain (FDTD) simulations reveal the size influence of Au NPs in ternary TAC photocatalysts. This work suggests that the rational design of bifunctional Au NPs coupling with slow photon effect could largely promote hydrogen production from visible-light driven water splitting. (c) 2021 Elsevier Inc. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000704428600004 Publication Date 2021-07-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9797 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.233 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 4.233
Call Number UA @ admin @ c:irua:182531 Serial 6886
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Author Rivera Julio, J.
Title Cálculos ab initio de sistemas 2D y de baja dimensionalidad Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) 137 p.
Keywords Doctoral thesis; Condensed Matter Theory (CMT)
Abstract
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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:176996 Serial 6718
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Author Blidar, A.-M.
Title The development of sensitive and selective electrochemical methods for the detection of antibiotics Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) 139 p.
Keywords Doctoral thesis; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Abstract The discovery of antibiotics represented one of the greatest breakthroughs in medicine. Their success combined with an increasing intensive use is apparently bound to be also their undoing. This is due to the development of acquired antibiotic resistance, leading to inefficient antibiotherapy and even to the impossibility of treatment and death. The development and spread of antibiotic resistance are fueled by the widespread presence of trace levels of antibiotics residue, in various media, from environment to aliments. One of the solutions is the rigorous monitoring of the levels of antibiotics, which in term requires an almost constant development of new, more accessible analytical methods, especially screening methods, capable of decentralized analysis. In this direction, the electrochemical detection of antibiotics represents a very viable alternative. In this context, the aim of this thesis was to develop new electrochemical methods for the detection of antibiotics by employing and expanding on several strategies, like biomimetic sensors and electrochemical fingerprinting. Five studies were described in this thesis, that can be roughly divided in three categories, based on the analytical strategy employed. The first group is represented by direct electrochemical methods. The second group focuses on the use of biomimetic elements, molecularly imprinted polymers and aptamers. The hyphenation of electrochemical methods with other analytical methods was explored in the last group. In the last study, included in this group, the singlet oxygen-based photoelectrochemical approach was used for the detection of a phenolic antibiotic, rifampicin. The originality of the thesis consists in the testing and development of new approaches to various strategies used in electrochemical detection, revealing new insights in the field of electrochemical detection of antibiotics. The complex electrochemical fingerprint and the mechanism of the electrochemical oxidation were created and investigated, respectively, for the antibiotic vancomycin. New sensitive nanoplatforms were prepared by employing and combining new protocols. Additionally, important contributions were brought through the study involving the singlet oxygen-based detection of rifampicin. We demonstrated how a photocatalyst can exhibit analyte selectivity by strongly interacting with a complex phenolic compound, rifampicin. Summing up, the studies presented in this thesis will have an important impact in the field of electrochemical detection of antibiotics.
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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:182955 Serial 7804
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Author Gielis, J.
Title Double helix of phyllotaxis : analysis of the geometric model of plant morphogenesis, by Boris Rozin Type Review
Year 2021 Publication Quarterly Review Of Biology Abbreviated Journal Q Rev Biol
Volume 96 Issue 2 Pages (up) 139-140
Keywords Review; Sustainable Energy, Air and Water Technology (DuEL)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2021-05-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0033-5770; 1539-7718 ISBN Additional Links UA library record
Impact Factor 4.25 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 4.25
Call Number UA @ admin @ c:irua:178829 Serial 7824
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Author Tiwari, S.; Van de Put, M.L.; Sorée, B.; Vandenberghe, W.G.
Title Ab initio modeling of few-layer dilute magnetic semiconductors Type P1 Proceeding
Year 2021 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, 2021, Dallas, TX Abbreviated Journal
Volume Issue Pages (up) 141-145
Keywords P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract We present a computational model to model the magnetic structure of two-dimensional (2D) dilute-magnetic-semiconductors (DMS) both the monolayers and multilayers using first-principles density functional theory (DFT), as well as their magnetic phase transition as a function of temperature using Monte-Carlo simulations. Using our method, we model the magnetic structure of bulk, bilayer, and monolayer MoS2 substitutionally doped with Fe atoms. We find that the out-of-plane interaction in bilayer MoS2 is weakly ferromagnetic, whereas in bulk MoS2 it is strongly anti-ferromagnetic. Finally, we show that the magnetic order is more robust in bilayer Fe-doped MoS2 compared to the monolayer and results in a room-temperature FM at an atomic substitution of 14-16%.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000766985400034 Publication Date 2021-11-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-6654-0685-7 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:187291 Serial 7401
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Author Skorikov, A.
Title Fast approaches for investigating 3D elemental distribution in nanomaterials Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) 143 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract
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:178855 Serial 6795
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Author de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S.
Title Optimal experiment design for nanoparticle atom counting from ADF STEM images Type H2 Book chapter
Year 2021 Publication Advances in imaging and electron physics T2 – Advances in imaging and electron physics Abbreviated Journal
Volume Issue Pages (up) 145-175
Keywords H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab
Abstract In this chapter, the principles of detection theory are used to quantify the probability of error for atom counting from high-resolution scanning transmission electron microscopy (HRSTEM) images. Binary and multiple hypothesis testing have been investigated in order to determine the limits to the precision with which the number of atoms in a projected atomic column can be estimated. The probability of error has been calculated when using STEM images, scattering cross-sections or peak intensities as a criterion to count atoms. Based on this analysis, we conclude that scattering cross-sections perform almost equally well as images and perform better than peak intensities. Furthermore, the optimal STEM detector design can be derived for atom counting using the expression of the probability of error. We show that for very thin objects the low-angle annular dark-field (LAADF) regime is optimal and that for thicker objects the optimal inner detector angle increases.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2021-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume 217 Series Issue Edition
ISSN ISBN 978-0-12-824607-8; 1076-5670 Additional Links UA library record
Impact Factor Times cited Open Access Not_Open_Access
Notes ERC Consolidator project funded by the European Union grant #770887 Picometrics Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:177530 Serial 6785
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Author De wael, A.
Title Model-based quantitative scanning transmission electron microscopy for measuring dynamic structural changes at the atomic scale Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) xiv, 146 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract Nanomaterialen kunnen uiterst interessante eigenschappen vertonen voor een verscheidenheid aan veelbelovende toepassingen, gaande van zonnecrème tot batterijen voor elektrische auto’s. Een nanometer is een miljard keer kleiner dan een meter. Op deze schaal kunnen de materiaaleigenschappen volledig verschillen van bulkmaterialen op grotere schaal. Bovendien hangen de eigenschappen van nanomaterialen sterk af van hun exacte grootte en vorm. Kleine verschillen in de posities van de atomen, in de grootte-orde van een picometer (nog eens duizend maal kleiner dan een nanometer), kunnen de fysische eigenschappen al drastisch beïnvloeden. Daarom is een betrouwbare kwantificering van de atomaire structuur van kritisch belang om de evolutie naar materiaalontwerp mogelijk te maken en inzicht te verwerven in de relatie tussen de fysische eigenschappen en de structuur van nanomaterialen. Daarnaast kan de atomaire structuur van nanomaterialen ook veranderen in de loop van de tijd ten gevolge van verschillende fysische processen. Het onderzoek dat in deze thesis gepresenteerd wordt, maakt het mogelijk om de dynamische structuurveranderingen van nanomaterialen betrouwbaar te kwantificeren op atomaire schaal door gebruik te maken van raster transmissie elektronenmicroscopie (STEM). Ik heb dit gerealiseerd door methodes te ontwikkelen waarmee ik het aantal atomen “achter elkaar” kan tellen in elke atoomkolom van een nanomateriaal, en dit op basis van beelden opgenomen met een elektronenmicroscoop. Een belangrijk verschil met telmethodes voor de analyse van een enkel beeld is het schatten van de kans dat een atoomkolom atomen zal verliezen of bijkrijgen van het ene naar het andere beeld in de tijdreeks. Deze kwantitatieve methode kan het ontrafelen van de tijdsafhankelijke structuur-eigenschappen relatie van een nanomateriaal mogelijk maken, wat uiteindelijk kan leiden tot efficiënter design en productie van nanomaterialen voor innovatieve toepassingen.
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:179514 Serial 6870
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Author Zhang, L.
Title Characteristic diagnosis of atmospheric discharge plasma and kinetics study of reactive species Type Doctoral thesis
Year 2021 Publication Abbreviated Journal
Volume Issue Pages (up) XVIII, 148 p.
Keywords Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Low-temperature plasma has received extensive attention due to its promising application prospects in the field of air pollutants degradation and energy conversion. To fulfill the need for particular applications, constructing stable plasma sources and investigating the interaction mechanisms between plasma and substances have been hot research topics. This thesis reports the diagnosis and improvement of plasma sources, diagnosis of the active species in plasma and a modeling study of chemical kinetics processes. The main research contents are as follows: In Chapter 3, a diffuse sine AC dielectric barrier discharge (DBD) is successfully obtained by optimizing the electrode structure. It is found that using double-layer dielectric plates can limit the discharge current intensity and significantly improve the discharge uniformity. The electrical characteristics and gas temperature with different operating time show that the discharge stability is also improved by using double-layer dielectric plates. In Chapter 4, nanosecond pulses are employed to generate diffuse DBD plasmas. Three main discharge stages are distinguished by ICCD images, i.e., the streamer breakdown from the needle tip to the plate electrode, the regime transition from streamer to diffuse plasma, and the propagation of surface discharge on the plate electrode surface. The chapter reveales that in nanosecond pulsed discharges the vibrational temperature of N2 increases with the discharge duration, while the rotational temperature mainly stays constant, which means electron energy is transferred into the vibrational levels, but gas heating is not obvious during the discharge pulse. In Chapter 5, both sine AC DBD and nanosecond pulsed DBD, studied in Chapter 2 and 3, are used for formaldehyde degradation. It is found that nanosecond pulsed DBD has more homogenous characteristics, better stability, and lower plasma gas temperature. Moreover, the energy consumption of nanosecond pulsed DBD is much lower than that of AC DBD. In Chapter 6, a 0D chemical kinetics model is developed to investigate the underlying plasma chemistry of methane dry reforming in a nanosecond pulsed discharge. An overview of the dominant reaction pathways of CO2 and CH4 conversion into the major products is given. Furthermore, most of the CO2 molecules are populated into vibrational states during the pulse. Hence, the vibrational states of CO2 play an important role in its dissociation process. In general, this PhD thesis contributes to a better insight in the mechanisms of sinusoidal AC DBD and nanosecond pulsed DBD plasmas and their applications, i.e., decomposition of formaldehyde and dry reforming of methane.
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:183166 Serial 7605
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