Records |
Author |
Vos, L.; Van Grieken, R. |
Title |
Preparation of conducting electrodes from biological samples for multi-element trace analysis by spark-source mass spectrometry or emission spectrometry |
Type |
A1 Journal article |
Year |
1984 |
Publication |
Analytica chimica acta |
Abbreviated Journal |
|
Volume |
164 |
Issue |
|
Pages |
83-90 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Four decomposition procedures frequently used for biological material (dry ashing, open wet digestion, wet digestion in a teflon bomb and low-temperature ashing) are optimized for the conversion of biological samples to conducting electrodes suitable for multi-element trace determinations by spark-source mass spectrometry or emission spectrometry. The optimized procedures are evaluated with respect to contamination, retention and preconcentration of the trace elements, homogeneity of the electrodes and precision of the final results. Both dry-ashing methods are prone to losses by volatilization; simple dry ashing suffers from contamination problems during electrode preparation. Wet digestion gives better precision; digestion with nitric/sulfuric acids in an open flask is the method of choice for most elements being simpler and giving lower blanks than the bomb method. |
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Wos |
A1984ABC2700007 |
Publication Date |
2002-07-25 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2670; 1873-4324 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:116443 |
Serial |
8411 |
Permanent link to this record |
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Author |
Cabal, A.; Schalm, O.; Eyskens, P.; Willems, P.; Harth, A.; van Espen, P. |
Title |
Comparison of x-ray absorption and emission techniques for the investigation of paintings |
Type |
A1 Journal article |
Year |
2015 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
|
Volume |
44 |
Issue |
3 |
Pages |
141-148 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Four x-ray techniques: computed radiography, emission radiography, energy-resolved radiography and imaging x-ray fluorescence were compared using four mock-up panel paintings. The paintings have different stratigraphy and pigments and are representative for different historical periods. One of the paintings has a hidden underlying painting. The type of pigments used mainly influences the information obtained by both the emission and absorption measurements; high-Z white pigment and high-Z color pigments giving the best contrast. Each of the techniques revealed interesting aspects of the paintings, but none of them could reveal the hidden painting to a satisfactory level. Due to the statistical quality of the spectral data, x-ray fluorescence gives elemental images with high contrast. The radiographic images are better to reveal the internal structure. Imaging x-ray fluorescence and energy-resolved radiography measurements can be done simultaneously, and the combination has the highest potential for the study of complex multilayer paintings. Copyright (c) 2015 John Wiley & Sons, Ltd. |
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Wos |
000353644500010 |
Publication Date |
2015-02-05 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:126016 |
Serial |
7698 |
Permanent link to this record |
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Author |
Lenaerts, S.; Honoré, M.; Huyberechts, G.; Roggen, J.; Maes, G. |
Title |
In situ infrared and electrical characterization of tin dioxide gas sensors in nitrogen/oxygen mixtures at temperatures up to 720 K |
Type |
A1 Journal article |
Year |
1994 |
Publication |
Sensors and actuators : B : chemical |
Abbreviated Journal |
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Volume |
19 |
Issue |
|
Pages |
478-482 |
Keywords |
A1 Journal article |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
FT-IR spectroscopy and impedance measurements of tin dioxide sensor materials at working temperatures up to 450 °C in atmospheres with varying O2/N2 ratio are used as an in situ probe to study the interactions at the surface of the semiconducting oxide. Every diminution in the oxygen content above the sample induces a broad IR absorption band (X-band) between 2300700 cm−1 with a few small peaks in the 1400850 cm−1 region of the spectrum superimposed on it. The X-band results from the enchanced electron concentration in the bulk of the tin dioxide domain. The fine structure is due to the absorption of several kinds of surface oxygen species associated vibration modes. The porous tin dioxide consists of domains were the outward shell is depleted of electrons by the formation of adsorbed O− species on oxygen surface sites, SO(O− species. In our proposed model for the impedance data this gives rise to a parallel RpCp circuit for the domain boundary characteristics and to an Rs parameter for the intradomain resistance. The evolution of these IR and impedance spectroscopic effects with temperature and oxygen content is used to set up, to confirm and refine a physicochemical operation model of tin dioxide gas sensor. This model consists of a sensitizing reaction sequence in the presence of oxygen and a gas-detection reaction sequence when a reducing gas is present. Based on this model, the principal disadvantages of this type of gas sensor become clear. Every factor that influences the concentration of SO(O−) species, causes a conductance modification. If we can control and direct the nature, the number and the arrangement of the tin dioxide domains, a directed development and improvement of the sensor characteristics is possible. |
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Wos |
A1994NN90000040 |
Publication Date |
2002-07-25 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0925-4005 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:82014 |
Serial |
5962 |
Permanent link to this record |
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Author |
Potgieter-Vermaak, S.S.; Mmari, A.; Van Grieken, R.; McCrindle, R.I.; Potgieter, J.H. |
Title |
Degradation of galvanised iron roofing material in Tanzania by atmospheric corrosion |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Corrosion engineering science and technology |
Abbreviated Journal |
|
Volume |
46 |
Issue |
5 |
Pages |
642-650 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Galvanised iron is popular in many applications, particular as a roofing material. However, just like other materials, especially metallic ones, it is prone to degradation by corrosion. In this particular study, the degradation of galvanised roof sheets was investigated at a coastal, urban and rural site in Tanzania, Africa. Samples were exposed to various outdoor environments over a period of 3 years. In addition, some accelerated laboratory investigations were conducted in different simulated air pollution environments in an artificial corrosion chamber constructed for this purpose to supplement the outdoor exposure tests. It was found that the combination of the tropical climate and increasing air pollution due to industrial development in the capital Dar-es-Salaam resulted in substantial atmospheric corrosion of the roof sheets, which eventually leads to failure and the necessity for replacement. The rural site had the lowest degree of atmospheric corrosion as expected. A combination of different corrosion products was identified as a result of the atmospheric corrosion by Raman and EDX analyses. The information gained from this investigation could be utilised to construct more durable structures requiring less frequent replacement and maintenance in future. |
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Place of Publication |
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Wos |
000294421100008 |
Publication Date |
2010-04-12 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1478-422x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:92094 |
Serial |
7758 |
Permanent link to this record |
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Author |
Gielis, J.; Tavkhelidze, I. |
Title |
A note on Generalized Möbius-Listing Bodies |
Type |
P1 Proceeding |
Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
31-39
T2 - Proceedings of the 1st International Sy |
Keywords |
P1 Proceeding; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Generalized Möbius-Listing surfaces and bodies generalize Möbius bands, and this research was motivated originally by solutions of boundary value problems. Analogous to cutting of the original Möbius band, for this class of surfaces and bodies, results have been obtained when cutting such bodies or surfaces. In general, cutting leads to interlinked and intertwined different surfaces or bodies, resulting in very complex systems. However, under certain conditions, the result of cutting can be a single surface or body, which reduces complexity considerably. These conditions are based on congruence and rotational symmetry of the resulting cross sections after cutting, and on the knife cutting the origin |
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Place of Publication |
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Wos |
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Publication Date |
2023-11-29 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
978-90-833839-0-3 |
ISBN |
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Additional Links |
UA library record |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:201047 |
Serial |
9063 |
Permanent link to this record |
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Author |
Gielis, J.; Tavkhelidze, I.; Ricci, P.E. |
Title |
Generalized Möbius-Listing bodies and the heart |
Type |
A3 Journal article |
Year |
2023 |
Publication |
Sn – 2247-689x |
Abbreviated Journal |
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Volume |
13 |
Issue |
2 |
Pages |
58-70 |
Keywords |
A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Generalized Möbius-Listing surfaces and bodies generalize Möbius bands, and this research was motivated originally by solutions of boundary value problems. Analogous to cutting of the original Möbius band, for this class of surfaces and bodies, results have been obtained when cutting such bodies or surfaces. The results can be applied in a wide range of fields in the natural science, and here we propose how they can serve as a model for the heart and the circulatory system. |
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Wos |
http://rjm-cs.ro/2023v13i2_7.pdf#page=1 |
Publication Date |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record; http://rjm-cs.ro/2023v13i2_7.pdf#page=1 |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:200773 |
Serial |
9043 |
Permanent link to this record |
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Author |
Fougerolle, Y.D.; Truchetet, F.; Demonceaux, C.; Gielis, J. |
Title |
A robust evolutionary algorithm for the recovery of rational Gielis curves |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Pattern recognition |
Abbreviated Journal |
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Volume |
46 |
Issue |
8 |
Pages |
2078-2091 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Gielis curves (GC) can represent a wide range of shapes and patterns ranging from star shapes to symmetric and asymmetric polygons, and even self intersecting curves. Such patterns appear in natural objects or phenomena, such as flowers, crystals, pollen structures, animals, or even wave propagation. Gielis curves and surfaces are an extension of Lamé curves and surfaces (superquadrics) which have benefited in the last two decades of extensive researches to retrieve their parameters from various data types, such as range images, 2D and 3D point clouds, etc. Unfortunately, the most efficient techniques for superquadrics recovery, based on deterministic methods, cannot directly be adapted to Gielis curves. Indeed, the different nature of their parameters forbids the use of a unified gradient descent approach, which requires initial pre-processings, such as the symmetry detection, and a reliable pose and scale estimation. Furthermore, even the most recent algorithms in the literature remain extremely sensitive to initialization and often fall into local minima in the presence of large missing data. We present a simple evolutionary algorithm which overcomes most of these issues and unifies all of the required operations into a single though efficient approach. The key ideas in this paper are the replacement of the potential fields used for the cost function (closed form) by the shortest Euclidean distance (SED, iterative approach), the construction of cost functions which minimize the shortest distance as well as the curve length using R-functions, and slight modifications of the evolutionary operators. We show that the proposed cost function based on SED and R-function offers the best compromise in terms of accuracy, robustness to noise, and missing data. |
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Wos |
000317944800002 |
Publication Date |
2013-01-29 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-3203 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:107181 |
Serial |
8485 |
Permanent link to this record |
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Author |
Gielis, J.; Caratelli, D.; Fougerolle, Y.; Ricci, P.E.; Tavkelidze, I.; Gerats, T. |
Title |
Universal natural shapes : from unifying shape description to simple methods for shape analysis and boundary value problems |
Type |
A1 Journal article |
Year |
2012 |
Publication |
PLoS ONE |
Abbreviated Journal |
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Volume |
7 |
Issue |
9 |
Pages |
e29324-11 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Gielis curves and surfaces can describe a wide range of natural shapes and they have been used in various studies in biology and physics as descriptive tool. This has stimulated the generalization of widely used computational methods. Here we show that proper normalization of the Levenberg-Marquardt algorithm allows for efficient and robust reconstruction of Gielis curves, including self-intersecting and asymmetric curves, without increasing the overall complexity of the algorithm. Then, we show how complex curves of k-type can be constructed and how solutions to the Dirichlet problem for the Laplace equation on these complex domains can be derived using a semi-Fourier method. In all three methods, descriptive and computational power and efficiency is obtained in a surprisingly simple way. |
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Place of Publication |
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Wos |
000309517500001 |
Publication Date |
2012-09-30 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-6203 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:102202 |
Serial |
8711 |
Permanent link to this record |
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Author |
Gielis, J.; Grigolia, R. |
Title |
Lamé curves and Rvachev's R-functions |
Type |
A3 Journal article |
Year |
2022 |
Publication |
Sn – 1512-0066 |
Abbreviated Journal |
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Volume |
37 |
Issue |
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Pages |
1-4 |
Keywords |
A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Gielis transformations are a generalization of Lame curves. To combine domains, we can make use of the natural alliance between Lame's work and Rvachev's R-functions. A logical next step is the extension to n-valued logic dening dierent partitions. |
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Wos |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:189316 |
Serial |
7178 |
Permanent link to this record |
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Author |
Gielis, J.; Caratelli, D.; de Jong van Coevorden, M.; Ricci, P.E. |
Title |
The common descent of biological shape description and special functions |
Type |
H1 Book chapter |
Year |
2018 |
Publication |
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Abbreviated Journal |
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Volume |
230 |
Issue |
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Pages |
119-131
T2 - Differential and difference equations |
Keywords |
H1 Book chapter; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Gielis transformations, with their origin in botany, are used to define square waves and trigonometric functions of higher order. They are rewritten in terms of Chebyshev polynomials. The origin of both, a uniform descriptor and the origin of orthogonal polynomials, can be traced back to a letter of Guido Grandi to Leibniz in 1713 on the mathematical description of the shape of flowers. In this way geometrical description and analytical tools are seamlessly combined. |
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Wos |
000451375900010 |
Publication Date |
2018-05-08 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
978-3-319-75646-2; 2194-1009; 978-3-319-75647-9; 978-3-319-75646-2 |
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:150949 |
Serial |
7685 |
Permanent link to this record |
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Author |
Hoeks, C.; Azadi, H.; Khachak, P.R.; Troyo-Dieguez, E.; Van Passel, S.; Witlox, F. |
Title |
Reforming land-tenure systems in South Africa : routes to socio-economic and agricultural sustainability |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Development policy review |
Abbreviated Journal |
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Volume |
32 |
Issue |
6 |
Pages |
647-674 |
Keywords |
A1 Journal article; Economics; Law |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Given the historical development of land tenure in South Africa, the aim of this article is to examine the best routes to alleviate poverty and retain sustainable agriculture in the country. First, a theoretical framework is presented that relates land tenure to sustainability, and three historical periods (pre-colonial, colonial, and apartheid) are then considered to explain the changes in land tenure and their consequences. The progress and main limitations of post-apartheid land reform to approach agricultural sustainability and alleviate poverty are discussed. Based on the analysis, different possibilities for future land reform are elaborated, followed by some recommendations for future land-reform policies in South Africa. |
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Wos |
000342755600001 |
Publication Date |
2014-09-29 |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
3 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:122509 |
Serial |
6241 |
Permanent link to this record |
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Author |
Tang, T.; Strokal, M.; van Vliet, M.T.H.; Seuntjens, P.; Burek, P.; Kroeze, C.; Langan, S.; Wada, Y. |
Title |
Bridging global, basin and local-scale water quality modeling towards enhancing water quality management worldwide |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Current Opinion in Environmental Sustainability |
Abbreviated Journal |
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Volume |
36 |
Issue |
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Pages |
39-48 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Global water quality (WQ) modeling is an emerging field. In this article, we identify the missing linkages between global and basin/local-scale WQ models, and discuss the possibilities to fill these gaps. We argue that WQ models need stronger linkages across spatial scales. This would help to identify effective scale-specific WQ management options and contribute to future development of global WQ models. Two directions are proposed to improve the linkages: nested multiscale WQ modeling towards enhanced water management, and development of next-generation global WQ models based-on basin/local-scale mechanistic understanding. We highlight the need for better collaboration among WQ modelers and policy-makers in order to deliver responsive water policies and management strategies across scales. |
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Wos |
000460234600006 |
Publication Date |
2018-11-07 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1877-3435 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:158643 |
Serial |
7568 |
Permanent link to this record |
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Author |
Admasu, W.F. |
Title |
Socioeconomic and environmental impact of expropriation of agricultural land for urbanisation in Ethiopia |
Type |
Doctoral thesis |
Year |
2021 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
162 p. |
Keywords |
Doctoral thesis; Engineering Management (ENM) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Globally, incorporation of agricultural lands into the urban boundary has been a common phenomenon. Governments use various alternatives to access the required land, including land expropriation procedures, which refers to the compulsorily taking of land from the landholders without their consent by paying compensation. In Ethiopia, the urban population is growing rapidly which resulted into an increase in the demand for urban land for housing construction, public services provision, and infrastructure developments. As the Ethiopian constitution prohibits sale of landholders, governments, at various levels, have been expropriating land from the surrounding farmers to meet the demand for urban land. The general objective of this thesis is to improve the understanding of the impacts of local land deals for urbanization on socioeconomics of farmers and the environment. The findings of this thesis revealed that there are gaps in the current practices of land expropriation for urban expansion that should be improved. The results showed that the compensation paid to the affected farmers is found to be economically inappropriate, i.e., not enough to restore the affected farmers’ livelihoods, in contrast with the land laws that allows a compensation amount that would put previous land users in a better or the same wellbeing as before the land expropriation. In addition, it is indicated that the land expropriation process does not take into account the value of ecosystem services, which are benefits obtain from the land, and important for the wellbeing of the society. We conclude that while land expropriation is an important tool to obtain land from the landholders when it is needed for public purposes, the practices in the study area show it is adversely affecting the socioeconomics of farmers and the environment. |
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ISBN |
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Additional Links |
UA library record |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:177909 |
Serial |
6944 |
Permanent link to this record |
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Author |
Finizola e Silva, M.; Van Schoubroeck, S.; Cools, J.; Aboge, D.O.; Ouma, M.; Olweny, C.; Van Passel, S. |
Title |
Local actors' perspectives on sustainable food value chains : evidence from a Q-methodology study in Kenya |
Type |
Administrative Services |
Year |
2024 |
Publication |
Journal of Environmental Studies and Sciences |
Abbreviated Journal |
|
Volume |
14 |
Issue |
1 |
Pages |
36-51 |
Keywords |
Administrative Services; A1 Journal article; Engineering sciences. Technology; Engineering Management (ENM) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Governments and international organizations are increasingly determined to create more sustainable food value chains (SFVCs). However, only little empirical evidence is available on how SFVCs are understood. Enquiring African food value chain actors allows gathering valuable insights into their perception of sustainability, which characteristics of sustainable food value chains they prioritize, and which obstacles to a sustainable transformation they identify. By means of a Q-methodology involving interviews with 33 Kenyan respondents, four perspectives were distinguished. The first perspective, “economic productivity and growth,” prioritizes economic growth and has only limited attention to the social dimension of sustainability. The second perspective, “food security and food availability,” believes that ensuring food security should be the key goal of SFVCs. The third perspective, “environment first,” is dedicated to the environmental dimension of sustainability; the perspective implies that protecting natural resources is the primary way to sustain this level of production. The fourth perspective, “transformative knowledge,” entails that by innovating and sharing knowledge, food value chains can become more sustainable in different areas. Overall, this study provides reliable insights into how Kenyan food value chain actors perceive sustainability in their sector and which elements they believe should be prioritized when rethinking food systems. The study results are valuable for policy-making to further define an SFVC in Kenya and to pave the way for a sustainable transformation of the food sector in developing countries. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001063371200001 |
Publication Date |
2023-09-11 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
2190-6483 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
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Times cited |
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Open Access |
|
Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:199200 |
Serial |
9210 |
Permanent link to this record |
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|
|
Author |
Zhang, K. |
Title |
Revealing the correlation between titania support properties and propylphosphonic acid modification by in-depth characterization |
Type |
Doctoral thesis |
Year |
2023 |
Publication |
|
Abbreviated Journal |
|
Volume |
|
Issue |
|
Pages |
XVI, 262 p. |
Keywords |
Doctoral thesis; Laboratory of adsorption and catalysis (LADCA) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Grafting organophosphonic acids modification (PAs) on metal oxides has shown to be a flexible technology to tune the surface properties of metal oxides for various applications. Nevertheless, there are still puzzles that need to be addressed, such as the correlations between metal oxides properties (types of surface reactive sites) and the modification (modification degree), the correlations between metal oxides properties and the properties of modified surfaces. Moreover, the currently used liquid-phase method for the grafting has associated impeding effects of solvent on tailoring the modification degrees, and also causes the formation of metal phosphonate side products. The solid-phase method can induce the unwanted changes in crystal phase of supports. Based on these questions, the three titania supports with divergent surface properties were selected as the metal oxides supports investigated, propylphosphonic acid (3PA) modification was carried out under the same synthesis conditions: four different concentrations, two solvents (water or toluene), and one reaction time (4 h) and temperature (90 ). MeOH chemisorption was introduced to probe the surface (un)reactive sites for 3PA modification. On the other hand, MeOH chemisorption and inverse gas chromatography (IGC) were combined to characterize the changes in surface polarity and acidic properties induced by the modification. Next, a solid-phase method, manual grinding, was proposed to graft 3PA on titania, avoiding the impeding effects of solvent on improving modification degree and the formation of the titania phosphonate side products, as well as preserving the crystal phase. The results indicate that methanol chemisorption can qualitatively analyze the surface active sites that are consumed by 3PA modification, its chemisorption capacity shows the consistent trend with the maximum modification degree, hereby revealing the kinds of interactions that are important in controlling surface coverage. Titania supports is found to play an important role in changes in surface polarity and acidic properties by charactering the three modified titania samples at a similar modification degree using the methanol chemisorption coupled with in-situ infrared and thermogravimetric-mass spectrometer, and the IGC. Moreover, IGC provides additional information about the changes in binding modes. Furthermore, grafting 3PA modification on titania was achieved by manual grinding. Compared to the liquid-phase method, the maximum modification degree obtained by the manual grinding is 25 % higher while using 83.3 % or 75.0% lower amounts of expensive 3PA and limiting the formation of titania phosphonate side products. Compared to the reactive milling method, the proposed manual grinding method preserves the crystal phase(s) of titania. |
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Wos |
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Publication Date |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
|
ISBN |
|
Additional Links |
UA library record |
Impact Factor |
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Times cited |
|
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:198726 |
Serial |
8924 |
Permanent link to this record |
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|
|
Author |
Cataldo,.; Evangelista, H.; Simões, J.C.; Godoi, R.H.M.; Simmonds, I.; Hollanda, M.H.; Wainer, I.; Aquino, F.E.; Van Grieken, R. |
Title |
Mineral dust variability in central West Antarctica associated with ozone depletion |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Atmospheric chemistry and physics discussions |
Abbreviated Journal |
|
Volume |
12 |
Issue |
5 |
Pages |
12685-12714 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Here we show that mineral dust retrieved from an ice core in the central West Antarctic sector, spanning the last five decades, provides evidence that northerly air mass incursions into Antarctica, tracked by dust microparticles, have slightly declined. This result contrasts with dust in ice core records reported in West/coastal Antarctica, which show significant increases to the present day. We attribute that difference, in part, to changes in the regional climate regime triggered by the ozone depletion and its consequences for the polar vortex intensity. The vortex maintains the Antarctic central region relatively isolated from mid-latitude air mass incursions with implications to the intensification of the Westerlies and to a persistent positive phase of the Southern Annular Mode. We also show that variability of the diameter of insoluble microparticles in central West Antarctica can be modeled by linear/quadratic functions of both cyclone depth (energy) and wind intensity around Antarctica. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
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Publication Date |
2012-05-21 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1680-7367 |
ISBN |
|
Additional Links |
UA library record |
Impact Factor |
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Times cited |
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Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ admin @ c:irua:102568 |
Serial |
8251 |
Permanent link to this record |
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|
|
Author |
Anaf, W.; Schalm, O. |
Title |
Climatic quality evaluation by peak analysis and segregation of low-, mid-, and high-frequency fluctuations, applied on a historic chapel |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Building and environment |
Abbreviated Journal |
|
Volume |
148 |
Issue |
|
Pages |
286-293 |
Keywords |
A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Heritage-related guidelines and standards recommend stable climatic conditions, since these contribute to the extension of heritage collections life. As a result, numerous museums and other heritage institutions implement (expensive) mitigation measures to achieve stable conditions. Nevertheless, temperature and relative humidity fluctuations are often still observed. This contribution demonstrates that the analysis of temperature and humidity peaks and drops helps to identify hazards which cause fluctuations in different frequency ranges. This hazard identification provides information on the type of mitigation actions that are required in the near future and in which order they need to be implemented. The approach is illustrated with a case study. A 22 month monitoring campaign was performed in a chapel in the center of Antwerp (Belgium) where the climatic conditions are controlled with a heating, ventilation and air conditioning (HVAC) system. Low-, mid- and high-frequency fluctuations were separated and discussed for their hazards. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000457116500024 |
Publication Date |
2018-11-15 |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
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Series Issue |
|
Edition |
|
ISSN |
0360-1323 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ admin @ c:irua:157569 |
Serial |
7672 |
Permanent link to this record |
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|
|
Author |
Blommaerts, N. |
Title |
Plasmonic core shell nanoparticles : from synthesis to photocatalytic applications |
Type |
Doctoral thesis |
Year |
2019 |
Publication |
|
Abbreviated Journal |
|
Volume |
|
Issue |
|
Pages |
153 p. |
Keywords |
Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Het gebruik van plasmon-actieve nanodeeltjes heeft de laatste 10 jaar zeer veel interesse gewekt bij onderzoekers in verschillende toepassingsdomeinen zoals fotokatalyse of oppervlakte versterkte Raman spectroscopie. Er is echter een grote limiterende factor bij het gebruik van edelmetaal nanodeeltjes zoals goud en zilver en dat is de stabiliteit. Deze oxideren en aggregeren snel, zeker in oxidatieve omgeving zoals in lucht. Een interessante aanpak om plasmon-actieve nanodeeltjes te stabiliseren, is om ze te omgeven in een schil, met andere woorden om een kern-schil nanodeeltje te vormen. Er zijn een heel aantal verschillende manieren waarop kern-schil nanodeeltjes gesynthetiseerd kunnen worden. In eerste instantie werden metaal nanodeeltjes omgeven door een (dunne) TiO2 laag. Afhankelijk van de hoeveelheid TiO2 precursor kon de dikte van de laag gecontroleerd worden tot enkele nanometers dik. De stalen werden getest voor de fotokatalytische afbraak van een vaste laag stearinezuur waarbij toevoeging van 2 wt% metaal@TiO2 op P25 leidde tot een significante verbetering in afbraakefficiëntie in vergelijking met zuiver P25. Een andere manier voor het stabiliseren van metaal nanodeeltjes is door ze te omgeven met een polymeerschil. Op deze manier kon de laagdikte gecontroleerd worden met sub-nanometer controle wat een zeer belangrijke factor is voor de hoeveelheid near-field versterking dat buiten de polymeer schil kan gaan. Een XTT test werd uitgevoerd om te bepalen wat de zuurstofactivatie snelheid was van goud en zilver (en goud-zilver bimetallische) nanodeeltjes, al dan niet omgeven door een (niet-)geleidende polymeer laag. Wanneer de stalen gecoat werden met vier niet-geleidende polymeerlagen zakte de zuurstofactivatie nagenoeg tot nul. Aan de andere kant, als goud nanodeeltjes werden omgeven door een geleidende schil was er nog steeds zuurstofactivatie, hoewel lager dan in het geval van goud zonder laag. Het laatste deel van deze thesis focuste meer op mogelijke toepassingen in luchtzuivering. In dit werk werd een glazen buis, gecoat aan de binnenkant met (Ag@polymer gemodificeerd) TiO2, als een spiraal rond een UVA lamp gewikkeld. De geoptimaliseerde spiraalreactor werd dan vergeleken met een conventionele cilindervormige fotoreactor, met dezelfde dimensies en totale katalysatorbelading, over een grote range aan experimentele condities. Uit de resultaten bleek dat de spiraalreactor significant betere afbraakefficiënties vertoonde in vergelijking met de conventionele cilindervormige reactor over een grote range aan debieten. Een adsorptiestap in combinatie met de geoptimaliseerde spiraalreactor zou kunnen leiden tot een zeer krachtige luchtzuiveringstechnologie. |
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Corporate Author |
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Additional Links |
UA library record |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:164835 |
Serial |
8389 |
Permanent link to this record |
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Author |
Verreck, D.; Verhulst, A.S.; Van de Put, M.L.; Sorée, B.; Magnus, W.; Collaert, N.; Mocuta, A.; Groeseneken, G. |
Title |
Self-consistent 30-band simulation approach for (non-)uniformly strained confined heterostructure tunnel field-effect transistors |
Type |
P1 Proceeding |
Year |
2017 |
Publication |
Simulation of Semiconductor Processes and, Devices (SISPAD)AND DEVICES (SISPAD 2017) |
Abbreviated Journal |
|
Volume |
|
Issue |
|
Pages |
29-32 |
Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Heterostructures of III-V materials under a mechanical strain are being actively researched to enhance the performance of the tunnel field-effect transistor (TFET). In scaled III-V device structures, however, the interplay between the effects of strain and quantum confinement on the semiconductor band structure and hence the performance is highly non-trivial. We have therefore developed a computationally efficient quantum mechanical simulator Pharos, which enables self-consistent full-zone k.p-based simulations of III-V TFETs under a general non-uniform strain. We present the self-consistent procedure and demonstrate it on confined staggered bandgap GaAs0.5Sb0.5/In0.53Ga0.47As TFETs. We find a large performance degradation due to size-induced quantum confinement compared to non-confined devices. We show that some performance can be regained either by applying a uniform biaxial tensile strain or through the non-uniform strain profile at a lattice-mismatched heterostructure. |
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Corporate Author |
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Thesis |
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Publisher |
Ieee |
Place of Publication |
New york |
Editor |
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Wos |
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Publication Date |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
978-4-86348-610-2 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:149949 |
Serial |
4978 |
Permanent link to this record |
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|
Author |
Alfeld, M.; Broekaert, J.A.C. |
Title |
Mobile depth profiling and sub-surface imaging techniques for historical paintings : a review |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Spectrochimica acta: part B : atomic spectroscopy |
Abbreviated Journal |
|
Volume |
88 |
Issue |
|
Pages |
211-230 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Hidden, sub-surface paint layers and features contain valuable information for the art-historical investigation of a painting's past and for its conservation for coming generations. The number of techniques available for the study of these features has been considerably extended in the last decades and established techniques have been refined. This review focuses on mobile non-destructive subsurface imaging and depth profiling techniques, which allow for the in-situ investigation of easel paintings, i.e. paintings on a portable support. Among the techniques discussed are: X-ray radiography and infrared reflectography, which are long established methods and are in use for several decades. Their capabilities of element/species specific imaging have been extended by the introduction of energy/wavelength resolved measurements. Scanning macro-X-ray fluorescence analysis made it for the first time possible to acquire elemental distribution images in-situ and optical coherence tomography allows for the non-destructive study the surface paint layers in virtual cross-sections. These techniques and their variants are presented next to other techniques, such as Terahertz imaging, Nuclear Magnetic Resonance depth profiling and established techniques for non destructive testing (thermography, ultrasonic imaging and laser based interference methods) applied in the conservation of historical paintings. Next to selected case studies the capabilities and limitations of the techniques are discussed. (C) 2013 Elsevier B.V. All rights reserved. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000325838900028 |
Publication Date |
2013-07-19 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0584-8547; 1873-3565 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:112232 |
Serial |
8256 |
Permanent link to this record |
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Author |
Balemans, S.; Vlaeminck, S.E.; Torfs, E.; Hartog, L.; Zaharova, L.; Rehman, U.; Nopens, I. |
Title |
The impact of local hydrodynamics on high-rate activated sludge flocculation in laboratory and full-scale reactors |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Processes |
Abbreviated Journal |
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Volume |
8 |
Issue |
2 |
Pages |
131-18 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High rate activated sludge (HRAS) processes have a high potential for carbon and energy recovery from sewage, yet they suffer frequently from poor settleability due to flocculation issues. The process of flocculation is generally optimized using jar tests. However, detailed jar hydrodynamics are often unknown, and average quantities are used, which can significantly differ from the local conditions. The presented work combined experimental and numerical data to investigate the impact of local hydrodynamics on HRAS flocculation for two different jar test configurations (i.e., radial vs. axial impellers at different impeller velocities) and compared the hydrodynamics in these jar tests to those in a representative section of a full scale reactor using computational fluid dynamics (CFD). The analysis showed that the flocculation performance was highly influenced by the impeller type and its speed. The axial impeller appeared to be more appropriate for floc formation over a range of impeller speeds as it produced a more homogeneous distribution of local velocity gradients compared to the radial impeller. In contrast, the radial impeller generated larger volumes (%) of high velocity gradients in which floc breakage may occur. Comparison to local velocity gradients in a full scale system showed that also here, high velocity gradients occurred in the region around the impeller, which might significantly hamper the HRAS flocculation process. As such, this study showed that a model based approach was necessary to translate lab scale results to full scale. These new insights can help improve future experimental setups and reactor design for improved HRAS flocculation. |
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Wos |
000521167900088 |
Publication Date |
2020-01-24 |
Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2227-9717 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
; This research was funded by Research Foundation Flanders (FWO SB Grant 1.S.705.18N). ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:165420 |
Serial |
6543 |
Permanent link to this record |
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Author |
Lezaack, M.B.; Hannard, F.; Zhao, L.; Orekhov, A.; Adrien, J.; Miettinen, A.; Idrissi, H.; Simar, A. |
Title |
Towards ductilization of high strength 7XXX aluminium alloys via microstructural modifications obtained by friction stir processing and heat treatments |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Materialia |
Abbreviated Journal |
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Volume |
20 |
Issue |
|
Pages |
101248 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High strength 7XXX aluminium series reach exceptional strength, higher than all other industrial aluminium alloys. However, they suffer from a lack of ductility compared to softer series. This work presents a procedure to improve the ductility of 7475 Al alloy in high strength condition, reaching a true fracture strain of 70% at full 500 MPa T6 yield strength. Using friction stir processing (FSP) and post-FSP heat treatments, 100% of industrial rolled material T6 yield stress is maintained but a 180% increase in fracture strain is measured for the processed material. This ductility improvement is studied by in-situ synchrotron X-ray tomography and is explained by the reduction of intermetallic particles size and the homogenization of their spatial distribution. Furthermore, the microstructure after FSP shows equiaxed refined grains which favour crack deviation as opposed to large cracks parallel to the elongated coarse grains in rolled plate. These results are paving the way to better formability and crashworthiness of 7XXX alloys. |
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Wos |
000718127100006 |
Publication Date |
2021-10-19 |
Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2589-1529 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
Not_Open_Access |
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:184145 |
Serial |
6894 |
Permanent link to this record |
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Author |
Yu, R.; Zeng, W.; Zhou, L.; Van Tendeloo, G.; Mai, L.; Yao, Z.; Wu, J. |
Title |
Layer-by-layer delithiation during lattice collapse as the origin of planar gliding and microcracking in Ni-rich cathodes |
Type |
A1 Journal article |
Year |
2023 |
Publication |
Cell reports physical science |
Abbreviated Journal |
|
Volume |
4 |
Issue |
7 |
Pages |
101480-14 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High-energy-density nickel (Ni)-rich cathode materials are used in commercial lithium (Li)-ion batteries for electric vehicles, but they suffer from severe structural degradation upon cycling. Planar gliding and microcracking are seeds for fatal mechanical fracture, but their origin remains unclear. Herein, we show that “layer-by -layer delithiation”is activated at high voltages during the charge process when the “lattice collapse”(a characteristic high-voltage lattice evolution in Ni-rich cathodes) occurs. Layer-by-layer deli-thiation is evidenced by direct observation of the consecutive lattice collapse using in situ scanning transmission electron micro-scopy (STEM). The collapsing of the lattice initiates in the expanded planes and consecutively extends to the whole crystal. Localized strain will be induced at lattice-collapsing interface where planar gliding and intragranular microcracks are generated to release this strain. Our study reveals that layer-by-layer delithia-tion during lattice collapse is the fundamental origin of the mechanical instability in single-crystalline Ni-rich cathodes. |
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Place of Publication |
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Language |
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Wos |
001048074500001 |
Publication Date |
2023-06-30 |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:198299 |
Serial |
8893 |
Permanent link to this record |
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Author |
Mao, D.; van de Weghe, H.; Lookman, R.; Vanermen, G.; de Brucker, N.; Diels, L. |
Title |
Resolving the unresolved complex mixture in motor oils using high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography |
Type |
A1 Journal article |
Year |
2009 |
Publication |
Fuel |
Abbreviated Journal |
|
Volume |
88 |
Issue |
2 |
Pages |
312-318 |
Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GC×GC) was used for detailed group-type characterization of hydrocarbons present in motor oils. With conventional GC, motor oil is not well separated due to its complexity, resulting in a hump in the chromatogram: the unresolved complex mixture (UCM). With HPLC-GC×GC, motor oil hydrocarbons can be quantitatively separated into four major groups: alkanes, cycloalkanes, alkenes and aromatics. Each group can be further separated and divided by ring number or carbon number. Three selected motor oil samples were characterized by HPLC-GC×GC including two conventional motor oils and a synthetic motor oil. Using a proprietary silver-modified HPLC column, the aromatic components in motor oils were baseline separated from the aliphatic UCM and were then further separated by GC×GC based on their aromatic ring numbers. Accordingly, the aliphatic components were separated by GC×GC based on their saturated ring numbers. This paper illustrates the capabilities of HPLC-GC×GC for reliable and detailed quantitative group-type characterization of hydrocarbons present in motor oils. |
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Wos |
000262129000011 |
Publication Date |
2008-09-27 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0016-2361 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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no |
Call Number |
UA @ admin @ c:irua:75748 |
Serial |
8474 |
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Author |
Van Winckel, T.; Liu, X.; Vlaeminck, S.E.; Takács, I.; Al-Omari, A.; Sturm, B.; Kjellerup, B.V.; Murthy, S.N.; De Clippeleir, H. |
Title |
Overcoming floc formation limitations in high-rate activated sludge systems |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Chemosphere |
Abbreviated Journal |
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Volume |
215 |
Issue |
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Pages |
342-352 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High-rate activated sludge (HRAS) is an essential cornerstone of the pursuit towards energy positive sewage treatment through maximizing capture of organics. The capture efficiency heavily relies on the degree of solid separation achieved in the clarifiers. Limitations in the floc formation process commonly emerge in HRAS systems, with detrimental consequences for the capture of organics. This study pinpointed and overcame floc formation limitations present in full-scale HRAS reactors. Orthokinetic flocculation tests were performed with varying shear, sludge concentration, and coagulant or flocculant addition. These were analyzed with traditional and novel settling parameters and extracellular polymeric substances (EPS) measurements. HRAS was limited by insufficient collision efficiency and occurred because the solids retention time (SRT) was short and colloid loading was high. The limitation was predominantly caused by impaired flocculation rather than coagulation. In addition, the collision efficiency limitation was driven by EPS composition (low protein over polysaccharide ratio) instead of total EPS amount. Collision efficiency limitation was successfully overcome by bio-augmenting sludge from a biological nutrient removal reactor operating at long SRT which did not show any floc formation limitations. However, this action brought up a floc strength limitation. The latter was not correlated with EPS composition, but rather EPS amount and hindered settling parameters, which determined floc morphology. With this, an analysis toolkit was proposed that will enable design engineers and operators to tackle activated solid separation challenges found in HRAS systems and maximize the recovery potential of the process. (C) 2018 Elsevier Ltd. All rights reserved. |
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Wos |
000450383400038 |
Publication Date |
2018-10-01 |
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Edition |
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ISSN |
0045-6535; 1879-1298 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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no |
Call Number |
UA @ admin @ c:irua:153978 |
Serial |
8350 |
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Author |
Cagnetta, C.; Saerens, B.; Meerburg, F.A.; Decru, S.O.; Broeders, E.; Menkveld, W.; Vandekerckhove, T.G.L.; De Vrieze, J.; Vlaeminck, S.E.; Verliefde, A.R.D.; De Gusseme, B.; Weemaes, M.; Rabaey, K. |
Title |
High-rate activated sludge systems combined with dissolved air flotation enable effective organics removal and recovery |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Bioresource technology |
Abbreviated Journal |
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Volume |
291 |
Issue |
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Pages |
121833 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High-rate activated sludge (HRAS) systems typically generate diluted sludge which requires further thickening prior to anaerobic digestion (AD), besides the need to add considerable coagulant and flocculant for the solids separation. As an alternative to conventional gravitational settling, a dissolved air flotation (DAF) unit was coupled to a HRAS system or a high-rate contact stabilization (HiCS) system. The HRAS-DAF system allowed up to 78% removal of the influent solids, and the HiCS-DAF 67%. Both were within the range of values typically obtained for HRAS-settler systems, albeit at a lower chemical requirement. The separated sludge had a high concentration of up to 47 g COD L−1, suppressing the need of further thickening before AD. Methanation tests showed a biogas yield of up to 68% on a COD basis. The use of a DAF separation system can thus enable direct organics removal at high sludge concentration and with low chemical needs. |
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Wos |
000480326200048 |
Publication Date |
2019-07-17 |
Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0960-8524 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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no |
Call Number |
UA @ admin @ c:irua:161098 |
Serial |
8036 |
Permanent link to this record |
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Author |
Meerburg, F.A.; Vlaeminck, S.E.; Roume, H.; Seuntjens, D.; Pieper, D.H.; Jauregui, R.; Vilchez-Vargas, R.; Boon, N. |
Title |
High-rate activated sludge communities have a distinctly different structure compared to low-rate sludge communities, and are less sensitive towards environmental and operational variables |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Water research |
Abbreviated Journal |
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Volume |
100 |
Issue |
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Pages |
137-145 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
High-rate activated sludge processes allow for the recovery of organics and energy from wastewaters. These systems are operated at a short sludge retention time and high sludge-specific loading rates, which results in a higher sludge yield and better digestibility than conventional, low-rate activated sludge. Little is known about the microbial ecology of high-rate systems. In this work, we address the need for a fundamental understanding of how high-rate microbial communities differ from low-rate communities. We investigated the high-rate and low-rate communities in a sewage treatment plant in relation to environmental and operational variables over a period of ten months. We demonstrated that (1) high-rate and low-rate communities are distinctly different in terms of richness, evenness and composition, (2) high-rate community dynamics are more variable and less shaped by deterministic factors compared to low-rate communities, (3) sub-communities of continuously core and transitional members are more shaped by deterministic factors than the continuously rare members, both in high-rate and low-rate communities, and (4) high-rate community members showed a co-occurrence pattern similar to that of low-rate community members, but were less likely to be correlated to environmental and operational variables. These findings provide a basis for further optimization of high-rate systems, in order to facilitate resource recovery from wastewater. |
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Wos |
000378448800014 |
Publication Date |
2016-05-08 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0043-1354; 1879-2448 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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no |
Call Number |
UA @ admin @ c:irua:139914 |
Serial |
8035 |
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Author |
Worobiec, A.; Samek, J.; Krata, A.; van Meel, K.; Krupińska, B.; Stefaniak, E.A.; Karaszkiewicz, P.; Van Grieken, R. |
Title |
Transport and deposition of airborne pollutants in exhibition areas located in historical buildings: study in Wawel Castle Museum in Cracow, Poland |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Journal of cultural heritage |
Abbreviated Journal |
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Volume |
11 |
Issue |
3 |
Pages |
354-359 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Historical buildings and castles that have been turned nowadays into museums, as an exhibition area for precious cultural heritage (CH) items, need more attention since they are CH objects by themselves. Moreover, the preservation techniques require often, significant interventions; however such changes are not always possible or are very limited. The aim of the present study was to investigate the influence of outdoor air pollution on the composition of particulate matter and gases inside the museum of Wawel Castle in Cracow, Poland. During this study a combination of micro and trace analysis techniques were applied, including energy dispersive X-ray fluorescence (EDXRF) and electron probe microanalysis (EPMA). An intensive transport of air pollutants coupled with accumulation of the particles inside the museum was noticed (considerably higher in winter than summer). A high content of carbon and organic matter agglomerated with inorganic particles was determined. Those particles are of special concern because of their adhesive properties and reactivity. It was also noted that the conditions inside the museum favour the reaction of the particles with gaseous pollutants. It was especially the case for nitrate particles. |
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000279867800017 |
Publication Date |
2010-03-25 |
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Edition |
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ISSN |
1296-2074 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Approved |
no |
Call Number |
UA @ admin @ c:irua:83277 |
Serial |
8698 |
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Author |
Nuyts, G.; Cagno, S.; Hellemans, K.; Veronesi, G.; Cotte, M.; Janssens, K. |
Title |
Study of the early stages of Mn intrusion in corroded glass by means of combined SR FTIR/\muXRF imaging and XANES spectroscopy |
Type |
P1 Proceeding |
Year |
2013 |
Publication |
Procedia Chemistry
T2 – Youth in Conservation of Cultural Heritage Conference (YOCOCU), June 18-20, 2012, University of Antwerp, Antwerp, Belgium |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
239-247 |
Keywords |
P1 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Historical glass, especially medieval glass, can undergo weathering under the influence of time and environmental conditions. The aim of this investigation was to better understand the processes involved in this natural degradation process by studying artificially altered glass samples prepared for the use of evaluation of conservation methods. Non-durable glass sensors produced by the Fraunhofer Institute (type M1.0) were used as a starting material for artificial alteration. These were immersed in acidic (pH = 0, 2, 4) and neutral solutions (1 h – 8 h). In a second stage the glass samples were immersed in a 0.5 M MnCl2 solution (24 h, 48 h and 72 h), allowing intrusion of Mn from the solution into the gel layer. The samples were characterized at different stages with reflectance FTIR spectroscopy, mu XRF mapping and mu XANES. All measurements were carried out at ESRF, beamline ID21. Reflectance FTIR spectroscopy measurements were performed in the 800 4000 cm(-1) range. Cluster analysis of the resulting maps evidenced the rapid growth of the gel layer in strong acidic conditions. The average spectra for each cluster feature show for the original glass a strong Si-O- stretching band between 900 and 1000 cm(-1), whereas the gel layer could be identified by the increasing Si-O-Si bands around 1100 and 1250 cm(-1). mu XRF maps were recorded at different stages of the experiment at energies around the Mn-K edge (6.539 keV) and with a step size of 2 by 2 m. These confirm the leaching of K+ and Ca+2 from the glass and the intrusion of Mn from the solution. Mn was found throughout the entire gel layer, but with a concentration gradient peaking at the surface. XANES point measurements were recorded at various points where Mn was present. No spatial variation was found, but linear combination fitting of the spectra with various Mn reference compounds indicated that Mn2+Mn23+O4 is the main Mn compound in the gel layer, as was hypothesised by Watkinson et al. The standard corroded glass samples studied here can be used for the evaluation of conservation treatments in follow-up experiments. (C) 2013 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility of the IA-CS (Italian Association of Conservation Scientists) and University of Antwerp |
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Wos |
000321673900030 |
Publication Date |
2013-04-17 |
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Abbreviated Series Title |
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Series Volume |
8 |
Series Issue |
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Edition |
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ISSN |
1876-6196 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
4 |
Open Access |
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Notes |
; This research was supported by the Interuniversity Attraction Poles Programme – Belgian Science Policy (IUAP VI/16). The text also presents results of GOA XANES “meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. We gratefully acknowledge ESRF for granting beamtime (experiment EC873). ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:109871 |
Serial |
5851 |
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Author |
Nuyts, G.; Cagno, S.; Jaroszewicz, J.; Wouters, H.; De Vis, K.; Caen, J.; Janssens, K. |
Title |
High-resolution desktop microcomputed tomography for the evaluation of reducing treatments on historical glass suffering from manganese browning |
Type |
H2 Book chapter |
Year |
2013 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
201-209 |
Keywords |
H2 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
Abstract ![sorted by Abstract field, ascending order (up)](img/sort_asc.gif) |
Historical glass, especially non-durable mediaeval glass, can undergo corrosion. This sometimes results in the formation of dark-coloured manganese-rich inclusions or stains that reduce the transparency of the glass. A conservation treatment with reducing or chelating agents may be considered with the aim of improving the transparency. In this paper, high-resolution desktop microcomputed tomography (µCT) is used in combination with element-specific twodimensional imaging methods for in situ monitoring of manganese removal by hydroxylamine hydrochloride from an archaeological stained-glass sample suffering from manganese browning and from artificially corroded model glass samples. µCT also proved itself useful for the study of the (re-)penetration of manganese into the gel layer during artificial corrosion of a model glass. |
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ISBN |
978-90-8932-113-8 |
Additional Links |
UA library record |
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Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:114604 |
Serial |
5641 |
Permanent link to this record |