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Author | Girma, H.; Huge, J.; Gebrehiwot, M.; Van Passel, S. | ||||
Title | Farmers' willingness to contribute to the restoration of an Ethiopian Rift Valley lake : a contingent valuation study | Type | A1 Journal article | ||
Year | 2021 | Publication | Environment, development and sustainability | Abbreviated Journal | |
Volume | 23 | Issue | 7 | Pages | 10646-10665 |
Keywords | A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM) | ||||
Abstract | Lakes provide considerable social, economic, and ecological benefits. However, lakes are shrinking and the water quality is declining, due to human pressures such as water withdrawal and land use change, particularly in the developing world. Despite this, information regarding the economic impact of lake level reduction and local willingness to support restoration programs is lacking. This study employed a contingent valuation method to estimate willingness to pay and to contribute labor to Lake Ziway restoration program, Ethiopia. Face-to-face interviews were administered to 259 randomly selected respondents. Our findings revealed that about one-third of the respondents are willing to pay and about two-third are willing to contribute labor to restore the lake. From the interval regression models, the annual mean willingness to pay was estimated about 21.0 USD for the status quo scenario (the program works to keep water levels constant at current levels) and 31.1 USD for the improvement scenario (the program works to increase the water levels permanently). The annual mean willingness to contribute labor was estimated about 27.7 man-days for the status quo and 39.3 man-days for the improvement scenarios. 'Farm income' positively influenced the willingness to pay together with 'farm plot area.' Similarly, labor contribution was positively influenced by 'farm plot area' and 'education' and negatively by 'farm plot distance.' The economic values derived from this study reflect societal preferences and can form a significant input for policymakers, in support of informed and evidence-based decision-making regarding lake management and restoration in developing countries like Ethiopia. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000590038300001 | Publication Date | 2020-11-16 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1387-585x | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | Times cited | Open Access | Not_Open_Access | ||
Notes | Approved | Most recent IF: NA | |||
Call Number | UA @ admin @ c:irua:174271 | Serial | 6926 | ||
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Author | Sebhatu, K.T.; Taheri, F.; Berhanu, T.; Maertens, M.; Van Passel, S.; D'Haese, M. | ||||
Title | Beyond focus : exploring variability of service provision of agricultural cooperatives | Type | A1 Journal article | ||
Year | 2021 | Publication | Annals of public and cooperative economics | Abbreviated Journal | |
Volume | 92 | Issue | 2 | Pages | 207-231 |
Keywords | A1 Journal article; Economics; Engineering Management (ENM) | ||||
Abstract | The wide array of services provided by agricultural cooperatives for their members is often not considered in academic studies. Addressing this gap in the literature, our paper explores the wide array of services provided by agricultural cooperatives and how these extend beyond those they were initially intended to provide. We study the extent and characteristics of service portfolios from 511 agricultural cooperatives in the Tigray region of Ethiopia. Results from two-limit Tobit models confirm that government and NGO-initiated cooperatives have a wide service portfolio compared to member-initiated cooperatives. In many of the studied cooperatives, the services they provide and their portfolios are more diverse than expected. Cooperatives seem to go beyond their focal areas of intervention. Also, those cooperatives that are more outward-oriented and where the chair has contact with other cooperatives or businesses, have a wider service portfolio. These results may help to explain the mixed findings on the impact of cooperative membership. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000583855500001 | Publication Date | 2020-10-27 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1370-4788; 1467-8292 | 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:173574 | Serial | 6916 | ||
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Author | Lavor, I.R.; Cavalcante, L.S.R.; Chaves, A.; Peeters, F.M.; Van Duppen, B. | ||||
Title | Probing the structure and composition of van der Waals heterostructures using the nonlocality of Dirac plasmons in the terahertz regime | Type | A1 Journal article | ||
Year | 2021 | Publication | 2d Materials | Abbreviated Journal | 2D Mater |
Volume | 8 | Issue | 1 | Pages | 015014 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | Dirac plasmons in graphene are very sensitive to the dielectric properties of the environment. We show that this can be used to probe the structure and composition of van der Waals heterostructures (vdWh) put underneath a single graphene layer. In order to do so, we assess vdWh composed of hexagonal boron nitride and different types of transition metal dichalcogenides (TMDs). By performing realistic simulations that account for the contribution of each layer of the vdWh separately and including the importance of the substrate phonons, we show that one can achieve single-layer resolution by investigating the nonlocal nature of the Dirac plasmon-polaritons. The composition of the vdWh stack can be inferred from the plasmon-phonon coupling once it is composed by more than two TMD layers. Furthermore, we show that the bulk character of TMD stacks for plasmonic screening properties in the terahertz regime is reached only beyond 100 layers. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000582820500001 | Publication Date | 2020-10-06 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2053-1583 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 6.937 | Times cited | 4 | Open Access | OpenAccess |
Notes | ; This work was financially supported by the Brazilian Council for Research (CNPq), Brazilian National Council for the Improvement of Higher Education (CAPES) and by the Research Foundation Flanders (FWO) through a postdoctoral fellowship to B.V.D. ; | Approved | Most recent IF: 6.937 | ||
Call Number | UA @ admin @ c:irua:173507 | Serial | 6696 | ||
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Author | Foumani, A.A.; Forster, D.J.; Ghorbanfekr, H.; Weber, R.; Graf, T.; Niknam, A.R. | ||||
Title | Atomistic simulation of ultra-short pulsed laser ablation of metals with single and double pulses : an investigation of the re-deposition phenomenon | Type | A1 Journal article | ||
Year | 2021 | Publication | Applied Surface Science | Abbreviated Journal | Appl Surf Sci |
Volume | 537 | Issue | Pages | 147775 | |
Keywords | A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | The demand for higher throughput in the processing of materials with ultra-short pulsed lasers has motivated studies on the use of double pulses (DP). It has been observed in such studies that at relatively high time delays between the two pulses, the ablated volume is lower than that for a single pulse (SP). This has been attributed to the shielding of the second pulse and the re-deposition of the material removed by the first pulse. The investigation of re-deposition in copper with the aid of atomistic simulations is the main objective of this study. Nevertheless, a computational investigation of SP-ablation and experimental measurement of the SP-ablation depths and threshold fluence are also covered. The applied computational apparatus comprises a combination of molecular dynamics with the two-temperature model and the Helmholtz wave equation. The analysis of the simulation results shows that the derived quantities like the SP-ablation threshold fluence and the ratio of DP ablation depth to SP-ablation depth are in agreement with the experimental values. An important finding of this study is that the characteristics of the re-deposition process are highly dependent on the fluence. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000582798700006 | Publication Date | 2020-09-13 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0169-4332 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.387 | Times cited | 2 | Open Access | Not_Open_Access |
Notes | ; The authors thank the Center for High-Performance Computing at Shahid Beheshti University of Iran (SARMAD) for making available the computational resources required for this work. ; | Approved | Most recent IF: 3.387 | ||
Call Number | UA @ admin @ c:irua:174299 | Serial | 6683 | ||
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Author | Alloul, A.; Wille, M.; Lucenti, P.; Bossier, P.; Van Stappen, G.; Vlaeminck, S.E. | ||||
Title | Purple bacteria as added-value protein ingredient in shrimp feed : Penaeus vannamei growth performance, and tolerance against Vibrio and ammonia stress | Type | A1 Journal article | ||
Year | 2021 | Publication | Aquaculture | Abbreviated Journal | Aquaculture |
Volume | 530 | Issue | Pages | 735788 | |
Keywords | A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) | ||||
Abstract | Aquafeeds contain protein ingredients such as fishmeal and soybean meal, yet their production puts pressure on the environment. Finding novel protein sources such as dried microbial biomass produced on recovered or renewable resources, so-called single-cell protein or microbial protein, can contribute to a more sustainable aquaculture industry. New microbial protein sources are emerging with photoheterotrophic grown purple non‑sulfur bacteria (PNSB) showing high potential, yet research of PNSB as added-value protein ingredient is limited. This research studied their use as a protein source for the white leg shrimp (Penaeus vannamei) and investigated the shrimp's tolerance against Vibrio and ammonia stress. A 28-day shrimp feeding trial was performed with a commercial formulation without PNSB as experimental control (diet i), two pure PNSB species, namely Rhodopseudomonas palustris (diets ii-iii), Rhodobacter capsulatus (diets iv-v) at two protein inclusion levels of 5 and 11 g PNSBprotein 100 g−1 feedprotein and a PNSB enriched culture at a protein inclusion level of 11 g PNSBprotein 100 g−1 feedprotein (diet vi). For the shrimp fed with Rb. capsulatus, 5–25% higher individual weights (p < .05) and better feed conversion ratios were observed relative to the commercial diet (1.3–1.4 vs. control 1.7 g feed g−1 biomass; p < .05). The diet containing Rps. palustris at 5 g PNSBprotein 100 g−1 feedprotein inclusion also showed higher individual weights (26%, p < .05) and a better feed conversion ratio compared to the commercial feed (1.3 vs. control 1.7 g feed g−1 biomass; p < .05). The challenge test subsequent to the feeding trial showed a higher tolerance against ammonia (3 mg N L−1) for shrimp fed with Rps. palustris (survival 63–75% vs. 8% commercial diet; p < .05). For a post-feeding challenge test with Vibrio parahaemolyticus TW01, mortality rates were equal among all treatments. Yet, in vitro tests in 96-Well plates and agar spot assays showed that the PNSB species (i) Rps. palustris, (ii) Rb. capsulatus, (iii) Rb. sphaeroides, (iv) Rhodospirillum rubrum and (v) Afifella marina suppressed the pathogens V. parahaemolyticus TW01 and V. campbellii LMG 21363. Overall, this study demonstrated the potential of PNSB as an added-value protein ingredient in shrimp nursery feed. This can contribute to a circular economy, as PNSB can be cultivated on recovered or renewable resources (e.g. wastewater). | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000582169700073 | Publication Date | 2020-08-08 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0044-8486 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 2.57 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 2.57 | |||
Call Number | UA @ admin @ c:irua:170549 | Serial | 8429 | ||
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Author | Ding, L.; Zhao, L.; Weng, Y.; Schryvers, D.; Liu, Q.; Idrissi, H. | ||||
Title | Atomic-scale investigation of the heterogeneous precipitation in the E (Al₁₈Mg₃Cr₂) dispersoid of 7075 aluminum alloy | Type | A1 Journal article | ||
Year | 2021 | Publication | Journal Of Alloys And Compounds | Abbreviated Journal | J Alloy Compd |
Volume | 851 | Issue | Pages | 156890 | |
Keywords | A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | The heterogeneous precipitation of the eta (MgZn2) phase on the E (Al18Mg3Cr2) dispersoids of the 7075 aluminum alloy was systematically investigated by atomic resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and energy dispersive X-ray spectrometry (EDX). It is found that coarse B particles are heterogeneously precipitated at the E particle interface after water quenching and isothermal aging at 120 degrees C. The incoherent E/Al interface is responsible for the high tendency of heterogeneous precipitation of the B phase. Two different orientation relationships (ORs) between the eta, E and Al matrix are identified: OR1 [2 (11) over bar0](eta)[011](E)//[(1) over bar 12](Al), (01 (1) over bar0)(eta)//(13 (3) over bar)(E)//(201)(Al), OR2 [(1) over bar 12](E)//[0001](eta)//[011](Al), (01 (1) over bar0 )(eta)//(220)(E)//(34 (4) over bar)(Al). The eta phase is preferential to nucleate along the {111}(E) or the {220}(E) planes, depending on its OR. The heterogeneous nucleation of B phase on the E particle could stabilize the E/Al interface by introducing a coherent E/eta interface, which increases the drive force of heterogeneous precipitation. The reorientation of eta phase and mutual diffusion of solute atoms could assist the coherency of the E/eta interface. The present results suggest that increasing the coherency of the E/Al interface is a promising method to suppress the heterogeneous precipitation of the eta phase. (C) 2020 Elsevier B.V. All rights reserved. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000579868900103 | Publication Date | 2020-08-25 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0925-8388 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor | 3.133 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 3.133 | |||
Call Number | UA @ admin @ c:irua:173503 | Serial | 6717 | ||
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Author | Bulut, P.; Beceren, B.; Yildirim, S.; Sevik, C.; Gurel, T. | ||||
Title | Promising room temperature thermoelectric conversion efficiency of zinc-blende AgI from first principles | Type | A1 Journal article | ||
Year | 2021 | Publication | Journal Of Physics-Condensed Matter | Abbreviated Journal | J Phys-Condens Mat |
Volume | 33 | Issue | 1 | Pages | 015501 |
Keywords | A1 Journal article; Condensed Matter Theory (CMT) | ||||
Abstract | The theoretical investigation on structural, vibrational, and electronic properties of zinc-blende (ZB) AgI were carried out employing first principles density functional theory calculations. Thermoelectric properties then were predicted through semi-classical Boltzmann transport equations within the constant relaxation time approximation. Equilibrium lattice parameter, bulk modulus, elastic constants, and vibrational properties were calculated by using generalized gradient approximation. Calculated properties are in good agreement with available experimental values. Electronic and thermoelectric properties were investigated both with and without considering spin-orbit coupling (SOC) effect which is found to have a strong influence on p-type Seebeck coefficient as well as the power factor of the ZB-AgI. By inclusion of SOC, a reduction of the band-gap and p-type Seebeck coefficients as well as the power factor was found which is the indication of that spin-orbit interaction cannot be ignored for p-type thermoelectric properties of the ZB-AgI. By using deformation potential theory for electronic relaxation time and experimentally predicted lattice thermal conductivity, we obtained aZTvalue 1.69 (0.89) at 400 K for n-type (p-type) carrier concentration of 1.5 x 10(18)(4.6 x10(19)) cm(-3)that makes ZB-AgI as a promising room temperature thermoelectric material. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000577217600001 | Publication Date | 2020-09-14 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0953-8984 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor | 2.649 | Times cited | Open Access | Not_Open_Access | |
Notes | Approved | Most recent IF: 2.649 | |||
Call Number | UA @ admin @ c:irua:193762 | Serial | 8425 | ||
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Author | Kleinhans, K.; Hallemans, M.; Huysveld, S.; Thomassen, G.; Ragaert, K.; Van Geem, K.M.; Roosen, M.; Mys, N.; Dewulf, J.; De Meester, S. | ||||
Title | Development and application of a predictive modelling approach for household packaging waste flows in sorting facilities | Type | A1 Journal Article | ||
Year | 2021 | Publication | Waste Management | Abbreviated Journal | Waste Management |
Volume | 120 | Issue | Pages | 290-302 | |
Keywords | A1 Journal Article; Engineering Management (ENM) ; | ||||
Abstract | Household packaging waste sorting facilities consist of complex networks of processes to separate diverse waste streams. These facilities are a key first step to re-enter materials into the recycling chain. However, so far there are no general methods to predict the performance of such sorting facilities, i.e. how efficiently the heterogeneous packaging waste is sorted into fractions with value for further recycling. In this paper, a model of the material flow in a sorting facility is presented, which allows changing the incoming waste composition, split factors on the sorting units as well as the setup of the sorting facility. The performance of the sorting facility is judged based on the purity of the output material (grade) and the recovery of the input material. A validation of the model was performed via a case study on Belgian post-consumer packaging waste with a selection of typical waste items that can be found in this stream. Moreover, the model was used to predict the possible sorting qualities of future Belgian postconsumer packaging waste after an extension of the allowed waste packaging items in the waste stream. Finally, a sensitivity analysis was performed on the split factors, which are a key data source in the model. Overall, the developed model is flexible and able to predict the performance of packaging waste sorting facilities as well as support waste management and design for recycling decisions, including future design of packaging, to ensure proper sorting and separation. |
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2020-12-16 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0956053X | ISBN | Additional Links | ||
Impact Factor | Times cited | Open Access | Not_Open_Access | ||
Notes | We would like to thank Indaver (https://www.indaver.com/been/home/), especially Erik Huybrechts, Eric Goddaert, Eline Meyvis and Erik Moerman, for their great support on this research. Furthermore, we would like to acknowledge the help of Colruyt (https://www.colruyt.be/) and CEFLEX (https://ceflex.eu/) for the pre-studies for this research. Moreover, we would like to show our appreciation for the financial support by the Catalisti-ICON project (HBC.2018.0262) MATTER (Mechanical and Thermochemical Recycling of mixed plastic waste) funded by Flanders Innovation & Entrepreneurship (VLAIO). We also thank the Interreg 2 Seas program PlastiCity that is co-funded by the European Regional Development Fund under subsidy contract No. 2S05-021 and the province of East-Flanders for funding this research. | Approved | Most recent IF: NA | ||
Call Number | ENM @ enm @ | Serial | 6667 | ||
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Author | Buchmayr, A.; Verhofstadt, E.; Van Ootegem, L.; Sanjuan Delmás, D.; Thomassen, G.; Dewulf, J. | ||||
Title | The path to sustainable energy supply systems: Proposal of an integrative sustainability assessment framework | Type | A1 Journal Article | ||
Year | 2021 | Publication | Renewable & Sustainable Energy Reviews | Abbreviated Journal | Renew Sust Energ Rev |
Volume | 138 | Issue | Pages | 110666 | |
Keywords | A1 Journal Article; Engineering Management (ENM) ; | ||||
Abstract | Energy supply is essential for the functioning and well-being of a society. Decision-makers are faced with the challenge to balance burdens and benefits of energy supply practices with the aim to achieve environmental, economic, and social sustainability. Literature exhibits a broad variety of sustainability assessment frameworks for energy supply technologies. However, there is no consensus on which aspects need to be covered for a comprehensive assessment of sustainability. While some aspects, such as environmental emission damage, receive predominant attention, there is a lack of coverage and adequate quantification for others. This led in the past to an unbalanced basis for decision-making. Based on an analysis of literature, 12 impact categories were identified for the assessment of energy technologies. The analysis included the judgement of quantification approaches regarding their significance for describing the impact categories and their maturity resulting in the proposal of 12 concrete indicators. A framework is proposed to manage and integrate the assessment of single impact categories. The framework produces normalized and weighted output indicators to use in the form of a dashboard or alternatively a single sustainability index for informed decision-making. Finally, the proposed sustainability assessment framework relies on life cycle, local impact, and supply chain risks assessment. It consists of both well-established assessment methods as well as suggestions for new indicators in order to allow a full assessment of all impact categories. It thereby goes beyond the isolated assessment of impacts and offers the basis for comparison of complete energy supply mixes. |
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2020-12-24 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1364-0321 | ISBN | Additional Links | ||
Impact Factor | 8.05 | Times cited | Open Access | Not_Open_Access | |
Notes | The authors acknowledge the financial support received from the Special Research Fund (Bijzonder Onderzoeksfonds – BOF) of Ghent University under grant agreement number BOF.24Y.2018.003. | Approved | Most recent IF: 8.05 | ||
Call Number | ENM @ enm @ | Serial | 6680 | ||
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Author | Thomassen, G.; Huysveld, S.; Boone, L.; Vilain, C.; Geysen, D.; Huysman, K.; Cools, B.; Dewulf, J. | ||||
Title | The environmental impact of household's water use: A case study in Flanders assessing various water sources, production methods and consumption patterns | Type | A1 Journal Article | ||
Year | 2021 | Publication | Science Of The Total Environment | Abbreviated Journal | Sci Total Environ |
Volume | 770 | Issue | Pages | 145398 | |
Keywords | A1 Journal Article; Engineering Management (ENM) ; | ||||
Abstract | Responsible water use and sustainable consumption and production are high on the agenda of multiple stakeholders. Different water supply sources are available, including tap water, bottled water, domestically harvested rainwater and domestically abstracted groundwater. The extent to which each of these water supply sources is used, differs over consumption patterns in various housing types, being detached houses, semi-detached houses, terraced houses and apartments. To identify the environmental impact of a household's water use and potential environmental impact reduction strategies, a holistic assessment is required. In this paper, the environmental impact of a household's water use in Flanders (Belgium) was assessed including four different water supply sources and four different consumption patterns by means of a life cycle assessment. The outcomes of this study reveal a large difference between the environmental impact of bottled water use, having a global warming impact of 259 kg CO2-eq.·m−3, compared to the other three supply sources. Tap water supply had the lowest global warming impact (0.17 kg CO2-eq.·m−3) and resource footprint (6.51 MJex·m−3) of all water supply sources. The most efficient strategy to reduce the environmental impact of household's water use is to shift the water consumption from bottled to tap water consumption. This would induce a reduction in global warming impact of the water use of an inhabitant in Flanders by on average 80%, saving 0.1 kg CO2-eq.·day−1 in case of groundwater-based tap water. These results provide insights into sustainable water use for multiple consumption patterns and can be used to better frame the environmental benefits of tap water use. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2021-01-27 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0048-9697 | ISBN | Additional Links | ||
Impact Factor | 4.9 | Times cited | Open Access | Not_Open_Access | |
Notes | This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. | Approved | Most recent IF: 4.9 | ||
Call Number | ENM @ enm @ | Serial | 6681 | ||
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Author | Pramanik, G.; Kvakova, K.; Thottappali, M.A.; Rais, D.; Pfleger, J.; Greben, M.; El-Zoka, A.; Bals, S.; Dracinsky, M.; Valenta, J.; Cigler, P. | ||||
Title | Inverse heavy-atom effect in near infrared photoluminescent gold nanoclusters | Type | A1 Journal Article | ||
Year | 2021 | Publication | Nanoscale | Abbreviated Journal | Nanoscale |
Volume | 13 | Issue | 23 | Pages | 10462-10467 |
Keywords | A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; | ||||
Abstract | Fluorophores functionalized with heavy elements show enhanced intersystem crossing due to increased spin–orbit coupling, which in turn shortens the fluorescence decay lifetime (<italic>τ</italic><sup>PL</sup>). This phenomenon is known as the heavy-atom effect (HAE). Here, we report the observation of increased<italic>τ</italic><sup>PL</sup>upon functionalisation of near-infrared photoluminescent gold nanoclusters with iodine. The heavy atom-mediated increase in<italic>τ</italic><sup>PL</sup>is in striking contrast with the HAE and referred to as inverse HAE. Femtosecond and nanosecond transient absorption spectroscopy revealed overcompensation of a slight decrease in lifetime of the transition associated with the Au core (ps) by a large increase in the long-lived triplet state lifetime associated with the Au shell, which contributed to the observed inverse HAE. This unique observation of inverse HAE in gold nanoclusters provides the means to enhance the triplet excited state lifetime. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2021-05-24 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2040-3364 | ISBN | Additional Links | ||
Impact Factor | 7.367 | Times cited | 7 | Open Access | OpenAccess |
Notes | The authors acknowledge support from GACR project Nr.18- 12533S. G. P. acknowledges support from EUSMI project No. E180200060; J.P. from the Ministry of Education, Youth and Sports of the Czech Republic – Program INTER-EXCELLENCE (LTAUSA19066). | Approved | Most recent IF: 7.367 | ||
Call Number | EMAT @ emat @ | Serial | 6950 | ||
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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 | 137 p. | ||
Keywords | Doctoral thesis; Condensed Matter Theory (CMT) | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | |||
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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 | Fatermans, J.; de Backer, A.; den Dekker, A.J.; Van Aert, S. | ||||
Title | Atom column detection | 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 | 177-214 | ||
Keywords | H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | By combining statistical parameter estimation and model-order selection using a Bayesian framework, the maximum a posteriori (MAP) probability rule is proposed in this chapter as an objective and quantitative method to detect atom columns from high-resolution scanning transmission electron microscopy (HRSTEM) images. The validity and usefulness of this approach is demonstrated to both simulated and experimental annular dark-field (ADF) STEM images, but also to simultaneously acquired annular bright-field (ABF) and ADF STEM image data. | ||||
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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:177531 | Serial | 6775 | ||
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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 | 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 | ||
Permanent link to this record | |||||
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 | 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 | ||
Permanent link to this record | |||||
Author | de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S. | ||||
Title | General conclusions and future perspectives | 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 | 243-253 | ||
Keywords | H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | This chapter provides an overview of statistical and quantitative methodologies that have pushed (scanning) transmission electron microscopy ((S)TEM) toward accurate and precise measurements of unknown structure parameters for understanding the relation between the structure of a material and its properties. Hereby, statistical parameter estimation theory has extensively been used which enabled not only measuring atomic column positions, but also quantifying the number of atoms, and detecting atomic columns as accurately and precisely as possible from experimental images. As a general conclusion, it can be stated that advanced statistical techniques are ideal tools to perform quantitative electron microscopy at the atomic scale. In the future, statistical methods will continue to be developed and novel quantification procedures will open up new possibilities for studying material structures at the atomic scale. | ||||
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:177533 | Serial | 6781 | ||
Permanent link to this record | |||||
Author | Fatermans, J.; de Backer, A.; den Dekker, A.J.; Van Aert, S. | ||||
Title | Image-quality evaluation and model selection with maximum a posteriori probability | 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 | 215-242 | ||
Keywords | H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | The maximum a posteriori (MAP) probability rule for atom column detection can also be used as a tool to evaluate the relation between scanning transmission electron microscopy (STEM) image quality and atom detectability. In this chapter, a new image-quality measure is proposed that correlates well with atom detectability, namely the integrated contrast-to-noise ratio (ICNR). Furthermore, the working principle of the MAP probability rule is described in detail showing a close relation to the principles of model-selection methods. | ||||
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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:177532 | Serial | 6782 | ||
Permanent link to this record | |||||
Author | de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S. | ||||
Title | Introduction | 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 | 1-28 | ||
Keywords | H2 Book chapter; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
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:177525 | Serial | 6784 | ||
Permanent link to this record | |||||
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 | 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 | ||
Permanent link to this record | |||||
Author | de Backer, A.; Fatermans, J.; den Dekker, A.J.; Van Aert, S. | ||||
Title | Statistical parameter estimation theory : principles and simulation studies | 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 | 29-72 | ||
Keywords | H2 Book chapter; Electron microscopy for materials research (EMAT); Vision lab | ||||
Abstract | In this chapter, the principles of statistical parameter estimation theory for a quantitative analysis of atomic-resolution electron microscopy images are introduced. Within this framework, electron microscopy images are described by a parametric statistical model. Here, parametric models are introduced for different types of electron microscopy images: reconstructed exit waves, annular dark-field (ADF) scanning transmission electron microscopy (STEM) images, and simultaneously acquired ADF and annular bright-field (ABF) STEM images. Furthermore, the Cramér-Rao lower bound (CRLB) is introduced, i.e. a theoretical lower bound on the variance of any unbiased estimator. This CRLB is used to quantify the precision of the structure parameters of interest, such as the atomic column positions and the integrated atomic column intensities. | ||||
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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:177527 | Serial | 6788 | ||
Permanent link to this record | |||||
Author | Skorikov, A. | ||||
Title | Fast approaches for investigating 3D elemental distribution in nanomaterials | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | 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 | ||
Permanent link to this record | |||||
Author | Esteban, D.A.; Vanrompay, H.; Skorikov, A.; Béché, A.; Verbeeck, J.; Freitag, B.; Bals, S. | ||||
Title | Fast electron low dose tomography for beam sensitive materials | Type | A1 Journal article | ||
Year | 2021 | Publication | Microscopy And Microanalysis | Abbreviated Journal | Microsc Microanal |
Volume | 27 | Issue | S1 | Pages | 2116-2118 |
Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2021-07-30 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1431-9276 | ISBN | Additional Links | UA library record | |
Impact Factor | 1.891 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 1.891 | |||
Call Number | EMAT @ emat @c:irua:183278 | Serial | 6813 | ||
Permanent link to this record | |||||
Author | Bruggeman, P.J.; Bogaerts, A.; Pouvesle, J.M.; Robert, E.; Szili, E.J. | ||||
Title | Plasma–liquid interactions | Type | A1 Journal Article | ||
Year | 2021 | Publication | Journal Of Applied Physics | Abbreviated Journal | J Appl Phys |
Volume | 130 | Issue | 20 | Pages | 200401 |
Keywords | A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; | ||||
Abstract | |||||
Address | |||||
Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | 2021-11-28 | ||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0021-8979 | ISBN | Additional Links | UA library record | |
Impact Factor | 2.068 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 2.068 | |||
Call Number | PLASMANT @ plasmant @c:irua:184245 | Serial | 6830 | ||
Permanent link to this record | |||||
Author | Pedrazo Tardajos, A. | ||||
Title | Advanced graphene supports for 3D in situ transmission electron microscopy | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | 247 p. | ||
Keywords | Doctoral thesis; Electron microscopy for materials research (EMAT) | ||||
Abstract | Transmission electron microscopy (TEM) is an ideal tool to investigate nanomaterials. The information from TEM experiments allows us to link the structure and composition of nanomaterials to their intrinsic physical properties. However, despite the significant evolution of the TEM field during the last two decades, major progress is still possible through the development of optimal TEM techniques and supports. The results presented in this thesis focus on the optimization of sample supports and their application. Among the different options, graphene has previously been reported as useful sample support for electron microscopy due to its unparalleled properties, for example, it is the thinnest known support and provides a protective effect to the sample under investigation. Unfortunately, commercial graphene grids show poor quality, in terms of intactness and cleanness, inhibiting their wide application within the field. Therefore, this thesis focuses on the application of optimized graphene TEM grids, obtained by transferring high quality graphene using an advanced procedure. This improvement on the transfer has enabled the visualization of materials with low contrast and high sensitivity towards the electron beam, such as surface ligands capping gold nanoparticles or metal halide perovskites. Furthermore, the implemented protocol is not only of interest for conventional TEM grids but also a major benefit for in situ TEM studies, where the sample is investigated in real time under certain stimuli. Hence, the same graphene transfer technology can be also applied to advanced in situ MEMS holders dedicated for both heating and gas experiments, where the thickness and insulating nature of the silicon nitride (Si3N4) support may hamper some applications. By engineering periodic arrays of holes in their Si3N4 membrane by focused ion beam, onto which the graphene is transferred, it has been possible to get proof-of-concept 3D in situ investigations of heat-induced morphological and compositional transformations of complex nanosystems. As an example, it has enabled the investigation of the possible phase-transition of metal halide perovskites upon heating using 2D and 3D structural characterization. Moreover, it has allowed the study of in situ three-dimensional nanoparticle dynamics during gas phase catalysis as well as the first steps that would lead towards the design and creation of the first Graphene Gas Cell. Consequently, implementation of the advanced graphene transfer technology described in this thesis is envisaged to impact a broad range of future experiments. | ||||
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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:181143 | Serial | 6836 | ||
Permanent link to this record | |||||
Author | Skorikov, A.; Heyvaert, W.; Albrecht, W.; Pelt, D.M.; Bals, S. | ||||
Title | EMAT Simulated 3D Nanoparticle Structures Dataset | Type | Dataset | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | |||
Keywords | Dataset; Electron microscopy for materials research (EMAT) | ||||
Abstract | This dataset contains 1000 simulated nanoparticle-like 3D structures and noisy EDX-like elemental maps based on them. These data are intended to be used for quantitative analysis of data processing methods in (EDX) tomography of nanoparticles and training the data-driven approaches for these tasks. The dataset is structured as follows: voxel_data/clean 3D voxel grid representation of the simulated nanoparticles. Voxel intensities are adjusted so that the total intensity equals 103. All 3D structures have unique identifiers in 0..999 range. The data derived from a 3D structure preserves this unique identifier. sinograms/clean Tilt series of projection images obtained from the corresponding 3D structures over an angular range of -75..75 degrees with a tilt step of 10 degrees to simulate a typical tilt series used in EDX tomography. Total intensity in each projection image equals 103. sinograms/noisy Tilt series of projection images corrupted with Poisson noise and an additional spatially uniform background noise. projections/clean Projection images extracted from the clean tilt series at 0 degrees tilt angle. projections/noisy Projection images extracted from the noisy tilt series at 0 degrees tilt angle. images/clean Visualizations of the clean projections as PNG images with the intensity range adjusted to 0..255 images/noisy Visualizations of the noisy projections as PNG images with the intensity range adjusted to 0..255 | ||||
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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 | Not_Open_Access | ||
Notes | Approved | Most recent IF: NA | |||
Call Number | UA @ admin @ c:irua:180615 | Serial | 6838 | ||
Permanent link to this record | |||||
Author | Du, K. | ||||
Title | In situ TEM study on the manipulation of ferroelectrics | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | 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 | ||
Permanent link to this record | |||||
Author | Prabhakara, V. | ||||
Title | Strain measurement for semiconductor applications with Raman spectroscopy and Transmission electron microscopy | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | 149 p. | ||
Keywords | Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) | ||||
Abstract | Scaling down the size of transistors has been a trend for several decades which has led to improved transistor performance, increased transistor density and hence the overall computation power of IC chips. The trend slowed in recent years due to reliability and power consumption issues at the nanoscale. Hence strain is introduced into transistor channels that has beneficial effects on improving the mobility of charge carriers, providing an alternative pathway for enhancing transistor performance. Therefore, monitoring strain is vital for the semiconductor industry. With the recent trend of decreasing device dimensions (FinFETS ~ 10-20nm) and strain modulation being used throughout, industry needs a reliable and fast method as quality control or defect characterisation. Such a universal strain measurement method does not exist, and one relies on a combination of quantitative in-line methods and complex off-line approaches. In this thesis, I investigated TEM and Raman spectroscopy-based methodologies for strain measurement. In terms of TEM methodologies, advancements are made for the STEM moiré imaging, targeting strain spatial resolution enhancement. I introduce advanced quadrature demodulation and phase stepping interferometry applied to STEM moiré that greatly enhances the spatial resolution while providing enhanced field of view and sensitivity for strain measurement. We introduce ways to reduce scan distortions in strain maps using an alternative scan strategy called “Block scanning” and the non-linear regression applied for strain extraction. Prospects for 3D strain analysis using high-resolution tomography is also investigated which gives direct access for the full second order strain tensors calculation. Finally, we compare strain measurements from TEM techniques with inline techniques like Raman spectroscopy. Raman stress measurement involves sensitive identification of the TO and LO phonon peaks. Raman spectrum of strained Ge transistor channel consists of strongly overlapping peaks within the spectral resolution of the spectrometer. Hence, the process of deconvolution of the two peaks is rather challenging. Hence, we explore new polarisation geometries like radially polarised incoming light which was shown to ease the deconvolution problem resulting in improved precision for Raman stress–strain measurements. | ||||
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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:182261 | Serial | 6847 | ||
Permanent link to this record | |||||
Author | Velazco Torrejón, A. | ||||
Title | Alternative scan strategies for high resolution STEM imaging | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | 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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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 | ||
Permanent link to this record | |||||
Author | Roegiers, J. | ||||
Title | Development of combined photocatalytic and active carbon fiber technology for indoor air purification based on Multiphysics models | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | XXX, 197 p. | ||
Keywords | Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL) | ||||
Abstract | Exposure to volatile organic compounds (VOCs) remains a major public health concern. Indoor VOC concentrations typically far exceed outdoor levels due to a variety of emission sources and the stringent insulation measures that are imposed today. Many attempts have been made to use photocatalysis for indoor air purification. In an ideal situation, photocatalysis is capable of complete mineralization of VOCs to H2O and CO2, without any byproduct formation. Moreover, the process can take place at standard atmospheric conditions, i.e. ambient temperature and atmospheric pressure. However, successful exploitation is still impeded due to low conversion efficiency, significant pressure loss (and hence a high energy consumption) and byproduct formation. In the first part of this thesis an attempt was made to tackles these problems by designing a novel type of photocatalytic (PCO) reactor. The PCO device consists of a cylindrical vessel filled with TiO2-coated glass tubes and equipped with UV fluorescence lamps. It was investigated in terms of fluid dynamics, coating properties, UV-light distribution and photocatalytic activity. Experimental data was later used to develop and calibrate a Multiphysics model. The model proved to be a useful tool for designing and upscaling the PCO reactor. Consequently, an optimized prototype reactor was constructed and tested according the CEN-EN-16846-1 standard for VOC removal. Although the prototype showed promising results for lab-scale conditions, it struggled with byproduct formation when purifying ppb-level VOCs. In the second part of this thesis, activated carbon adsorption was investigated in order to combine it with photocatalysis. Activated carbon fiber was opted for its fast kinetics, high adsorption capacity and thermo-electrical regeneration. The filter was studied in detail regarding the adsorption of polar and apolar VOCs at indoor air concentration levels and regeneration capabilities. Experimental data was used to develop a Multiphysics model for activated carbon adsorption as well. Consequently, a novel type of ACF filter was developed using the Multiphysics model, which was equipped with electrodes in the tips of the pleats for effective thermal regeneration. In the last part, the combination of both ACF and PCO was studied using a realistic case study. Based on the Multiphysics model, the feasibility of a so-called hybrid air purification device could be investigated. The Multiphysics model shows promising results for this hybrid PCO-ACF system and hence, a demo setup was constructed for future research. | ||||
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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:181137 | Serial | 6860 | ||
Permanent link to this record | |||||
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 | 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. | ||||
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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:179514 | Serial | 6870 | ||
Permanent link to this record |