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Author |
van Loon, A.; Noble, P.; de Man, D.; Alfeld, M.; Callewaert, T.; van der Snickt, G.; Janssens, K.; Dik, J. |
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Title |
The role of smalt in complex pigment mixtures in Rembrandt'sHomer1663: combining MA-XRF imaging, microanalysis, paint reconstructions and OCT |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Heritage science |
Abbreviated Journal |
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Volume |
8 |
Issue |
1 |
Pages |
90-19 |
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Keywords  |
A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
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Abstract |
As part of the NWO Science4ArtsREVISRembrandtproject (2012-2018), novel chemical imaging techniques were developed and applied to the study of Rembrandt's late experimental painting technique (1651-1669). One of the unique features in his late paintings is his abundant use of smalt: a blue cobalt glass pigment that he often combined with organic lake pigments, earth pigments and blacks. Since most of these smalt-containing paints have discolored over time, we wanted to find out more about how these paintings may have originally looked, and what the role of smalt was in his paint. This paper reports on the use of smalt in complex pigment mixtures in Rembrandt'sHomer(1663), Mauritshuis, The Hague. Macroscopic X-ray fluorescence imaging (MA-XRF) assisted by computational analysis, in combination with SEM-EDX analysis of paint cross-sections, provides new information about the distribution and composition of the smalt paints in the painting. Paint reconstructions were carried out to investigate the effect of different percentages of smalt on the overall color, the drying properties, translucency and texture of the paint. Results show that the influence of (the originally blue) smalt on the intended color of the paint of theHomeris minimal. However, in mixtures with high percentages of smalt, or when combined with more transparent pigments, it was concluded that the smalt did produce a cooler and darker paint. It was also found that the admixture of opaque pigments reduced the translucent character of the smalt. The drying tests show that the paints with (cobalt-containing) smalt dried five times faster compared to those with glass (without cobalt). Most significantly, the texture of the paint was strongly influenced by adding smalt, creating a more irregular surface topography with clearly pronounced brushstrokes. Optical coherence tomography (OCT) was used as an additional tool to reveal differences in translucency and texture between the different paint reconstructions. In conclusion, this study confirmed earlier assumptions that Rembrandt used substantial amounts of smalt in his late paintings, not for its blue color, but to give volume and texture to his paints, to deepen their colors and to make them dry faster. |
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Wos |
000565893700001 |
Publication Date |
2020-09-04 |
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ISSN |
2050-7445 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.5 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 2.5; 2020 IF: NA |
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Call Number |
UA @ admin @ c:irua:171995 |
Serial |
8659 |
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Author |
Simonsen, K.P.; Poulsen, J.N.; Vanmeert, F.; Ryhl-Svendsen, M.; Bendix, J.; Sanyova, J.; Janssens, K.; Mederos-Henry, F. |
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Title |
Formation of zinc oxalate from zinc white in various oil binding media: the influence of atmospheric carbon dioxide by reaction with 13CO2 |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Heritage science |
Abbreviated Journal |
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Volume |
8 |
Issue |
1 |
Pages |
126 |
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Keywords |
A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The formation of metal oxalates in paintings has recently gained a great deal of interest within the field of heritage science as several types of oxalate compounds have been identified in oil paintings. The present work investigates the formation of metal oxalates in linseed oil in the presence of the artists' pigments zinc white, calcite, lead white, zinc yellow, chrome yellow, cadmium yellow, cobalt violet, and verdigris. The oil paint films were artificially photo-aged by exposure to UVA light at low and high relative humidity, and afterwards analysed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that, compared to the other pigments investigated, zinc white is especially prone to metal oxalate formation and that high humidity is a crucial factor in this process. Consequently, the reactivity and photo-aging of ZnO in various oil binding media was investigated further under simulated solar radiation and at high relative humidity levels. ATR-FTIR showed that zinc oxalate is formed in all oil binding media while X-ray powder diffraction (PXRD) revealed it was mainly present in an amorphous state. To examine whether atmospheric CO2(g) has any influence on the formation of zinc oxalate, experiments with isotopically enriched (CO2(g))-C-13 were performed. Based on ATR-FTIR measurements, neither (ZnC2O4)-C-13 nor (ZnCO3)-C-13 were formed which suggests that the carbon source for the oxalate formation is most likely the paint itself (and its oil component) and not the surrounding atmosphere. |
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Wos |
000596527000001 |
Publication Date |
2020-12-07 |
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ISSN |
2050-7445 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.5 |
Times cited |
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Open Access |
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Approved |
Most recent IF: 2.5; 2020 IF: NA |
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Call Number |
UA @ admin @ c:irua:174381 |
Serial |
7979 |
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Author |
Finizola e Silva, M.; Van Passel, S. |
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Title |
Climate-Smart Agriculture in the Northeast of Brazil: An Integrated Assessment of the Aquaponics Technology |
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A1 Journal Article |
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Year |
2020 |
Publication |
Sustainability |
Abbreviated Journal |
Sustainability-Basel |
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Volume |
12 |
Issue |
9 |
Pages |
3734 |
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Keywords |
A1 Journal Article; aquaponics; Aquaponova; Brazil; semi-arid region; food insecurity; cost–benefit analysis; socio-economic approach; climate-smart agriculture; Engineering Management (ENM) ; |
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Abstract |
The purpose of this study is to determine if aquaponic systems can reduce food insecurity in the semi-arid regions of Brazil and generate income for the beneficiaries. Aquaponics is a potentially sustainable way to produce food based on gardening, hydroponics and aquaculture. A case study, based on a project called Aquaponova, was developed. The aquaponic systems currently used in the project are non-commercial and designed for households with limited resources. The data based on six existing systems within this project were used to compare the costs and the benefits. The cost–benefit analysis covers four scenarios and three financing options. The results show that aquaponic systems have a large potential and can reduce food insecurity in semi-arid regions while generating income for the beneficiaries. Even if the system only produces 40% of the total estimated production, the system will still be feasible. However, the low opportunity cost of labour is an essential factor for obtaining these positive results. Moreover, the social benefits, such as a community spirit and the health benefits of the system, should not be underestimated. |
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Wos |
000537476200232 |
Publication Date |
2020-05-05 |
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ISSN |
2071-1050 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.9 |
Times cited |
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Notes |
We would like to express our gratitude to Francisco Fechine Borges who introduced Maíra Finizola e Silva the basics of aquaponics and gave her the opportunity to base her research on the data from the Aquaponova project. We would also like to thank the participants of the 2nd LA SDEWES conference in Buenos Aires (9–12 February 2020) for the useful comments and suggestions. |
Approved |
Most recent IF: 3.9; 2020 IF: 1.789 |
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Call Number |
ENM @ enm @c:irua:170074 |
Serial |
6382 |
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Author |
Fitawok, M.B.; Derudder, B.; Minale, A.S.; Van Passel, S.; Adgo, E.; Nyssen, J. |
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Title |
Modeling the Impact of Urbanization on Land-Use Change in Bahir Dar City, Ethiopia: An Integrated Cellular Automata–Markov Chain Approach |
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A1 Journal Article |
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Year |
2020 |
Publication |
Land |
Abbreviated Journal |
Land |
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Volume |
9 |
Issue |
4 |
Pages |
115 |
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Keywords |
A1 Journal Article; analytical hierarchy process; cellular automata; land-use change; Markov chain; urbanization; Engineering Management (ENM) ; |
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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. |
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Wos |
000533901100026 |
Publication Date |
2020-04-09 |
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ISSN |
2073-445X |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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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. |
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Most recent IF: NA |
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Call Number |
ENM @ enm @c:irua:169600 |
Serial |
6381 |
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Sebhatu, K.T.; Gezahegn, T.W.; Berhanu, T.; Maertens, M.; Van Passel, S.; D’Haese, M. |
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Conflict, fraud, and distrust in Ethiopian agricultural cooperatives |
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A1 Journal Article |
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Year |
2020 |
Publication |
Journal of Co-operative Organization and Management |
Abbreviated Journal |
Journal of Co-operative Organization and Management |
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Volume |
8 |
Issue |
1 |
Pages |
100106 |
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Keywords |
A1 Journal Article; Agricultural cooperatives; Cooperative size; Conflict; Fraud; Distrust; Ethiopia; Engineering Management (ENM) ; |
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Abstract |
Agricultural cooperatives are seen as an efficient way for smallholder farmers to create bargaining power in order to achieve poverty reduction and food security. However, the success of these cooperatives depends on their ability to maintain their social capital, which is at the core of collective action. A few studies have addressed issues of member participation, commitment, and trust, yet less is known about rural cooperatives in developing countries as a social organization. It is also unclear whether a relationship exists between cooperative size and the incidence of conflict, fraud, and distrust. Using unique data collected from 511 agricultural cooperatives in 12 districts of Tigray region in northern Ethiopia, this paper examines the effects of cooperative size on conflict, fraud, and distrust. We used instrumental variables (IV) probit estimation techniques, accounting for endogeneity of membership size, to confirm that cooperative size does affect the occurrence of conflict, fraud, and trust. The results also indicate that other influencing factors include: cooperative age, number of employees, payment of dividends based on transaction volume, and heterogeneity of member goals. |
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Wos |
000536594400001 |
Publication Date |
2020-04-28 |
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ISSN |
2213297X |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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The authors would like to thank the office of the twelve districts, facilitators and Cooperative Promotion Agency staff for their collaboration in facilitating the field survey, most of all the chair- and vice-chairpersons of the study Agricultural Cooperatives who had to respond to all our questions with seriousness and patience. |
Approved |
Most recent IF: NA |
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Call Number |
ENM @ enm @c:irua:170073 |
Serial |
6379 |
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Author |
Jamshidi, O.; Asadi, A.; Kalantari, K.; Movahhed Moghaddam, S.; Dadrass Javan, F.; Azadi, H.; Van Passel, S.; Witlox, F. |
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Title |
Adaptive capacity of smallholder farmers toward climate change: evidence from Hamadan province in Iran |
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A1 Journal Article |
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Year |
2020 |
Publication |
Climate And Development |
Abbreviated Journal |
Clim Dev |
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Pages |
1-11 |
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Keywords |
A1 Journal Article; Adaptive capacity; cross sectional survey; socio-economic variables; adaptation strategies; Hamadan province; Engineering Management (ENM) ; |
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The global climate is changing, and farmers must increase their adaptive capacity to avoid negative impacts. This study aimed to examine the adaptive capacity of farmers’ household to tolerate climate changes and identify factors affecting the climate in Hamadan province, Iran. The adaptive capacity was evaluated quantitatively by using 23 indicators and was categorized into high, moderate, low, and very low adaptive capacity. The study was based on a cross sectional survey and was conducted with a random sample of 280 household farmers distributed in five counties of Hamadan province in the west of the country whose climatic data revealed signs of climate change. The result showed that farmers’ negative perception toward climate change generally increases during dry seasons and decreases when the precipitation and water resources are more available. Regarding the available information, only 15% of farmers had a high level of adaptive capacity, while 10% of them were highly adapted, and 27.5% showed a very low level of adaptive capacity. Adaptive capacity in the current study was influenced by some socio-economic variables including total farm size, irrigated farm size, number of agricultural land plots, and perception and knowledge of climate change. |
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Wos |
000509193400001 |
Publication Date |
2020-01-25 |
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Edition |
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ISSN |
1756-5529 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.051 |
Times cited |
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Open Access |
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Notes |
The authors appreciate the comments of the anonymous reviewers and would like to thank them for their constructive feedback. Frank Witlox acknowledges funding received from the Estonian Research Council (PUT PRG306). |
Approved |
Most recent IF: NA |
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Call Number |
ENM @ enm @c:irua:166572 |
Serial |
6378 |
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