Home << 1 2 >>
List View
 | 
Citations
 | 
Details
   web
Records
Author Somsen, C.; Wassermann, E.F.; Kästner, J.; Schryvers, D.
Title Precursor phenomena in a quenched and aged Ni52Ti48 shape memory alloy Type A1 Journal article
Year 2003 Publication Journal de physique: 4 T2 – 10th International Conference on Martensitic Transformations, JUN 10-14, 2002, ESPOO, FINLAND Abbreviated Journal J Phys Iv
Volume 112 Issue Part 2 Pages 777-780
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We measured the electrical resistivity R(T) and specific heat C-p(T) between room temperature (RT) and 4.2 K as well as the microstructure by transmission electron microscopy (TEM) of a Ni-52 Ti-48 SMA quenched from 1000degreesC (B2-Phase range) to RT and then annealed for 1h at T=380degreesC, 550degreesC and 650degreesC. In the “as quenched” and the “650degreesC annealed” state no martensitic transformations (MT's) occur. The diffraction patterns show faint reflections originating from coherent Ni4Ti3 precipitates in an early state of formation. Additional reflections of the type 1/2 <110>, 1/2 <111> and 1/3 <110> result from various lattice displacement waves, which are precursors of the MT's to the B19' and R-phase, respectively. Indeed, high resolution TEM micrographs of the [001] zone of the “as quenched” sample reveal transverse 1/2 <110> <110> lattice displacement waves, precursors of the B19' martensite. The coherent Ni4Ti3 precipitates, homogeneously distributed on a small length scale, binder the MT's in the “as quenched” and the “650degreesC annealed” state, and thus only the precursors appear. When annealed at T=380degreesC, however, coherent Ni4Ti3 precipitates with a length of 10nm are clearly visible in TEM. These precipitates trigger the NIT from the B2 to the R-phase on cooling, as evidenced also by anomalies in R(T) and C-p(T). Annealing at T-550degreesC leads to the well known two step MT's from the B2 to the R-phase and then into the B19'-phase. These martensitic transitions are clearly seen as additional peaks in the specific heat and anomalies in the resistance, while the “as quenched” and 650degreesC annealed samples show weak features in R(T) and C-p(T).
Address
Corporate Author Thesis
Publisher Place of Publication Les Ulis Editor
Language Wos 000186503400036 Publication Date 2008-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1155-4339; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 2 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:102791 Serial 2694
Permanent link to this record
 
 
Author Ball, J.M.; Schryvers, D.
Title The analysis of macrotwins in NiAl martensite Type A1 Journal article
Year 2003 Publication Journal de physique: 4 T2 – 10th International Conference on Martensitic Transformations, JUN 10-14, 2002, ESPOO, FINLAND Abbreviated Journal J Phys Iv
Volume 112 Issue Part 1 Pages 159-162
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We present a theoretical study of macrotwins arising in cubic to tetragonal martensitic transformations. The results help to explain some features of such macrotwins observed in Ni65Al35.
Address
Corporate Author Thesis
Publisher Place of Publication Les Ulis Editor
Language Wos 000186503200024 Publication Date 2008-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1155-4339; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 11 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:103275 Serial 3569
Permanent link to this record
 
 
Author Nord, M.; Verbeeck, J.
Title Towards Reproducible and Transparent Science of (Big) Electron Microscopy Data Using Version Control Type P1 Proceeding
Year 2019 Publication Microscopy and microanalysis T2 – Microscopy & Microanalysis 2019, 4-8 August, 2019, Portland, Oregon Abbreviated Journal Microsc Microanal
Volume 25 Issue S2 Pages 232-233
Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2019-08-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1431-9276 ISBN Additional Links UA library record
Impact Factor 1.891 Times cited Open Access
Notes Approved Most recent IF: 1.891
Call Number EMAT @ emat @c:irua:164058 Serial 5377
Permanent link to this record
 
 
Author Nguyen, N.T.T.; Peeters, F.M.
Title Phase-diagram for the magnetic states of the Mn-ion subsystem in a magnetic quantum dot Type P1 Proceeding
Year 2010 Publication Journal of physics : conference series T2 – Conference on Quantum Dots 2010 (QD2010), APR 26-30, 2010, Nottingham, ENGLAND Abbreviated Journal
Volume Issue Pages 012032-12034
Keywords P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract The interplay between two types of spin-spin exchange interaction (namely of the electron with the Mn-ions and the Mn-ions with each other) that are governed by the positions of the Mn-ions and the magnetic field is studied in the case of a Mn-ion doped CdTe quantum dot. We investigate the formation of different magnetic phases and the existence of frustrated magnetic states due to the dominant contribution of the Mn-Mn energy.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000294907400032 Publication Date 2010-09-21
Series Editor Series Title Abbreviated Series Title
Series Volume 245 Series Issue Edition
ISSN (up) 1742-6596; ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes ; ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:113081 Serial 2582
Permanent link to this record
 
 
Author Nguyen, N.T.T.; Peeters, F.M.
Title The breakdown of Kohn's theorem in few-electron parabolic quantum dots doped with a single magnetic impurity Mn2+ Type P1 Proceeding
Year 2010 Publication Journal of physics : conference series T2 – Conference on Quantum Dots 2010 (QD2010), APR 26-30, 2010, Nottingham, ENGLAND Abbreviated Journal
Volume Issue Pages 012031-12034
Keywords P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract The cyclotron resonance (CR) absorption spectrum is calculated for a II-VI parabolic quantum dot (QD) containing few electrons and a single magnetic dopant (Mn(2+)). We find that Kohn's theorem no longer holds for this system and that the CR spectrum depends on the number of electrons inside the QD. The electron-Mn-ion interaction strength can be tuned for example by the magnetic field and by moving the Mn-ion to different positions inside the QD. We demonstrate that due to the presence of the Mn-ion the relative motion of the electrons couple with their center-of-mass motion through the electron-Mn-ion spin-spin exchange term resulting in an electron-electron interaction dependence of the magneto-optical absorption spectrum. At the ferromagnetic-antiferromagnetic transition we observe significant discontinuities in the CR lines.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000294907400031 Publication Date 2010-09-21
Series Editor Series Title Abbreviated Series Title
Series Volume 245 Series Issue Edition
ISSN (up) 1742-6596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 1 Open Access
Notes ; ; Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:113080 Serial 3572
Permanent link to this record
 
 
Author Fitawok, M.B.; Derudder, B.; Minale, A.S.; Van Passel, S.; Adgo, E.; Nyssen, J.
Title Stakeholder perspectives on farmers' resistance towards urban land-use changes in Bahir Dar, Ethiopia Type A1 Journal article
Year 2023 Publication Journal of land use science Abbreviated Journal
Volume 18 Issue 1 Pages 25-38
Keywords A1 Journal article; Engineering Management (ENM)
Abstract Owing to growing uncontrolled land-use change and urban expansion, farmers in urban fringes are struggling to sustain their livelihood. Farmers have been expressing their dissatisfaction at different times. This study analyzes the stakeholders' perspectives on the causes and outcomes of farmers' resistance to land-use change and urban expansion processes by zooming in on Bahir Dar, Ethiopia. The paper is based on focus group discussions with farmers in the neighboring villages, local agricultural extension experts, and, subsequently, key informant interviews of local government officials. Juxtaposing farmers' and local experts' positions reveals that inadequate compensations during land expropriation, lack of good governance in the urban expansion process, and inaccessibility of infrastructures are primary reasons for the farmers' struggle against urban expansion in the urban fringes. This study provides insights into the consequences of unplanned urban development challenges and may inform research and policymaking on sustainable urban development in the area and beyond.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000936397600001 Publication Date 2023-02-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1747-423x; 1747-4248 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.2 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 3.2; 2023 IF: NA
Call Number UA @ admin @ c:irua:195109 Serial 7368
Permanent link to this record
 
 
Author Fitawok, M.B.; Derudder, B.; Minale, A.S.; Van Passel, S.; Adgo, E.; Nyssen, J.
Title Modeling the Impact of Urbanization on Land-Use Change in Bahir Dar City, Ethiopia: An Integrated Cellular Automata–Markov Chain Approach Type A1 Journal Article
Year 2020 Publication Land Abbreviated Journal Land
Volume 9 Issue 4 Pages 115
Keywords A1 Journal Article; analytical hierarchy process; cellular automata; land-use change; Markov chain; urbanization; Engineering Management (ENM) ;
Abstract The fast-paced urbanization of recent decades entails that many regions are facing seemingly uncontrolled land-use changes (LUCs) that go hand in hand with a range of environmental and socio-economic challenges. In this paper, we use an integrated cellular automata–Markov chain (CA–MC) model to analyze and predict the urban expansion of and its impact on LUC in the city of Bahir Dar, Ethiopia. To this end, the research marshals high-resolution Landsat images of 1991, 2002, 2011, and 2018. An analytical hierarchy process (AHP) method is then used to identify the biophysical and socioeconomic factors underlying the expansion in the research area. It is shown that, during the period of study, built-up areas are rapidly expanding in the face of an overall decline of the farmland and vegetation cover. Drawing on a model calibration for 2018, the research predicts the possible geographies of LUC in the Bahir Dar area for 2025, 2034, and 2045. It is predicted that the conversions of other land-use types into built-up areas will persist in the southern, southwestern, and northeastern areas of the sprawling city, which can mainly be traced back to the uneven geographies of road accessibility, proximity to the city center, and slope variables. We reflect on how our findings can be used to facilitate sustainable urban development and land-use policies in the Bahir Dar area.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000533901100026 Publication Date 2020-04-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 2073-445X ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes The authors would like to thank the VLIR-UOS project for funding this research through Bahir Dar University—Institutional University Cooperation (BDU-IUC) program. Approved Most recent IF: NA
Call Number ENM @ enm @c:irua:169600 Serial 6381
Permanent link to this record
 
 
Author Chekol Zewdie, M.; Moretti, M.; Tenessa, D.B.; Ayele, Z.A.; Nyssen, J.; Tsegaye, E.A.; Minale, A.S.; Van Passel, S.
Title Agricultural technical efficiency of smallholder farmers in Ethiopia : a stochastic frontier approach Type A1 Journal article
Year 2021 Publication Land Abbreviated Journal
Volume 10 Issue 3 Pages 246
Keywords A1 Journal article; Engineering Management (ENM)
Abstract In the past decade, to improve crop production and productivity, Ethiopia has embarked on an ambitious irrigation farming expansion program and has introduced new large- and small-scale irrigation initiatives. However, in Ethiopia, poverty remains a challenge, and crop productivity per unit area of land is very low. Literature on the technical efficiency (TE) of large-scale and small-scale irrigation user farmers as compared to the non-user farmers in Ethiopia is also limited. Investigating smallholder farmers' TE level and its principal determinants is very important to increase crop production and productivity and to improve smallholder farmers' livelihood and food security. Using 1026 household-level cross-section data, this study adopts a technology flexible stochastic frontier approach to examine agricultural TE of large-scale irrigation users, small-scale irrigation users and non-user farmers in Ethiopia. The results indicate that, due to poor extension services and old-style agronomic practices, the mean TE of farmers is very low (44.33%), implying that there is a wider room for increasing crop production in the study areas through increasing the TE of smallholder farmers without additional investment in novel agricultural technologies. Results also show that large-scale irrigation user farmers (21.05%) are less technically efficient than small-scale irrigation user farmers (60.29%). However, improving irrigation infrastructure shifts the frontier up and has a positive impact on smallholder farmers' output.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000633846200001 Publication Date 2021-03-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 2073-445x 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:177647 Serial 6913
Permanent link to this record
 
 
Author Verreck, D.; Verhulst, A.S.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
Title Non-uniform strain in lattice-mismatched heterostructure tunnel field-effect transistors Type P1 Proceeding
Year 2016 Publication Solid-State Device Research (ESSDERC), European Conference T2 – 46th European Solid-State Device Research Conference (ESSDERC) / 42nd, European Solid-State Circuits Conference (ESSCIRC), SEP 12-15, 2016, Lausanne, SWITZERLAND Abbreviated Journal
Volume Issue Pages 412-415
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract Because of its localized impact on the band structure, non-uniform strain at the heterojunction between lattice-mismatched materials has the potential to significantly enlarge the design space for tunnel-field effect transistors (TFET). However, the impact of a complex strain profile on TFET performance is difficult to predict. We have therefore developed a 2D quantum mechanical transport formalism capable of simulating the effects of a general non-uniform strain. We demonstrate the formalism for the GaAsxSb(1-x)/InyGa(1-y) As system and show that a performance improvement over a lattice-matched reference is indeed possible, allowing for relaxed requirements on the source doping. We also point out that the added design parameter of mismatch is not free, but limited by the desired effective bandgap at the tunnel junction.
Address
Corporate Author Thesis
Publisher Ieee Place of Publication New york Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 978-1-5090-2969-3 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:138233 Serial 4358
Permanent link to this record