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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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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 |
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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Notes |
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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 |
Huang, W.; Li, Y.; Niklas, K.J.; Gielis, J.; Ding, Y.; Cao, L.; Shi, P. |
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Title |
A superellipse with deformation and its application in describing the cross-sectional shapes of a square bamboo |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Symmetry-Basel |
Abbreviated Journal |
Symmetry-Basel |
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Volume |
12 |
Issue |
12 |
Pages |
2073 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Many cross-sectional shapes of plants have been found to approximate a superellipse rather than an ellipse. Square bamboos, belonging to the genus Chimonobambusa (Poaceae), are a group of plants with round-edged square-like culm cross sections. The initial application of superellipses to model these culm cross sections has focused on Chimonobambusa quadrangularis (Franceschi) Makino. However, there is a need for large scale empirical data to confirm this hypothesis. In this study, approximately 750 cross sections from 30 culms of C. utilis were scanned to obtain cross-sectional boundary coordinates. A superellipse exhibits a centrosymmetry, but in nature the cross sections of culms usually deviate from a standard circle, ellipse, or superellipse because of the influences of the environment and terrain, resulting in different bending and torsion forces during growth. Thus, more natural cross-sectional shapes appear to have the form of a deformed superellipse. The superellipse equation with a deformation parameter (SEDP) was used to fit boundary data. We find that the cross-sectional shapes (including outer and inner rings) of C. utilis can be well described by SEDP. The adjusted root-mean-square error of SEDP is smaller than that of the superellipse equation without a deformation parameter. A major finding is that the cross-sectional shapes can be divided into two types of superellipse curves: hyperellipses and hypoellipses, even for cross sections from the same culm. There are two proportional relationships between ring area and the product of ring length and width for both the outer and inner rings. The proportionality coefficients are significantly different, as a consequence of the two different superellipse types (i.e., hyperellipses and hypoellipses). The difference in the proportionality coefficients between hyperellipses and hypoellipses for outer rings is greater than that for inner rings. This work informs our understanding and quantifying of the longitudinal deformation of plant stems for future studies to assess the influences of the environment on stem development. This work is also informative for understanding the deviation of natural shapes from a strict rotational symmetry. |
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Wos |
000602546300001 |
Publication Date |
2020-12-15 |
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ISSN |
2073-8994 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.7 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 2.7; 2020 IF: 1.457 |
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Call Number |
UA @ admin @ c:irua:174472 |
Serial |
8622 |
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Author |
Milovanović, S.P.; Andelkovic, M.; Covaci, L.; Peeters, F.M. |
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Title |
Band flattening in buckled monolayer graphene |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
102 |
Issue |
24 |
Pages |
245427 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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Abstract |
The strain fields of periodically buckled graphene induce a periodic pseudomagnetic field (PMF) that modifies the electronic band structure. From the geometry, amplitude, and period of the periodic pseudomagnetic field, we determine the necessary conditions to access the regime of correlated phases by examining the band flattening. As compared to twisted bilayer graphene the proposed system has the advantages that (1) only a single layer of graphene is needed, (2) one is not limited to hexagonal superlattices, and (3) narrower flat bandwidth and larger separation between flat bands can be induced. We, therefore, propose that periodically strained graphene single layers can become a platform for the exploration of exotic many-body phases. |
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Wos |
000602844600007 |
Publication Date |
2020-12-28 |
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Series Editor |
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Series Volume |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
27 |
Open Access |
OpenAccess |
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Notes |
; S.P.M. is supported by the Flemish Science Foundation (FWO). We thank E. Y. Andrei, Y. Jiang, and J. Mao for fruitful discussions. ; |
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:175021 |
Serial |
6684 |
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Author |
Guo, J.; Clima, S.; Pourtois, G.; Van Houdt, J. |
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Title |
Identifying alternative ferroelectric materials beyond Hf(Zr)O-₂ |
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A1 Journal article |
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Year |
2020 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl Phys Lett |
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Volume |
117 |
Issue |
26 |
Pages |
262903 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A database-driven approach combined with ab initio density functional theory (DFT) simulations is used to identify and simulate alternative ferroelectric materials beyond Hf(Zr)O-2. The database-driven screening method identifies a class of wurtzite ferroelectric materials. DFT simulations of wurtzite magnesium chalcogenides, including MgS, MgSe, and MgTe, show their potential to achieve improved ferroelectric (FE) stability, simple atomistic unit cell structure, and large FE polarization. Strain engineering can effectively modulate the FE switching barrier height for facilitating FE switching. The effect of the piezoelectric property on the FE switching barrier heights is also examined. |
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Wos |
000608049700003 |
Publication Date |
2020-12-28 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0003-6951; 1077-3118 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 4; 2020 IF: 3.411 |
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Call Number |
UA @ admin @ c:irua:176053 |
Serial |
6766 |
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Author |
Clima, S.; O'Sullivan, B.J.; Ronchi, N.; Bardon, M.G.; Banerjee, K.; Van den Bosch, G.; Pourtois, G.; van Houdt, J. |
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Title |
Ferroelectric switching in FEFET : physics of the atomic mechanism and switching dynamics in HfZrOx, HfO2 with oxygen vacancies and Si dopants |
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P1 Proceeding |
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Year |
2020 |
Publication |
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Keywords |
P1 Proceeding; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The fine balance between dipole-field energy and anion drift force defines the switching mechanism during polarization reversal: for the first time we show that only Pbcm mechanism obeys the ferroelectric switching physics, whereas P4(2)/nmc (or any other) mechanism does not. However, with lower energy barrier, it represents an important antiferroelectric mechanism. Constraints relaxation can lead to 90 degrees polarization rotation (domain deactivation). Intrinsically, the Si/VO-doping can switch faster than undoped HfO2 or HfZrOx. Theoretical Arrhenius model / intrinsic material switching (DFT) overestimates the switching speed extracted from experiments. |
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Wos |
000717011600218 |
Publication Date |
2021-03-11 |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
978-1-7281-8888-1 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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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 |
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Call Number |
UA @ admin @ c:irua:184730 |
Serial |
7963 |
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Author |
Cerruti, M.; Stevens, B.; Ebrahimi, S.; Alloul, A.; Vlaeminck, S.E.; Weissbrodt, D.G. |
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Title |
Enrichment and aggregation of purple non-sulfur bacteria in a mixed-culture sequencing-batch photobioreactor for biological nutrient removal from wastewater |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Frontiers in Bioengineering and Biotechnology |
Abbreviated Journal |
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Volume |
8 |
Issue |
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Pages |
557234 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Mixed-culture biotechnologies are widely used to capture nutrients from wastewater. Purple non-sulfur bacteria (PNSB), a guild of anoxygenic photomixotrophic organisms, rise interest for their ability to directly assimilate nutrients in the biomass. One challenge targets the aggregation and accumulation of PNSB biomass to separate it from the treated water. Our aim was to enrich and produce a concentrated, fast-settling PNSB biomass with high nutrient removal capacity in a 1.5-L, stirred-tank, anaerobic sequencing-batch photobioreactor (SBR). PNSB were rapidly enriched after inoculation with activated sludge at 0.1 gVSS L–1 in a first batch of 24 h under continuous irradiance of infrared (IR) light (>700 nm) at 375 W m–2, with Rhodobacter reaching 54% of amplicon sequencing read counts. SBR operations with decreasing hydraulic retention times (48 to 16 h, i.e., 1–3 cycles d–1) and increasing volumetric organic loading rates (0.2–1.3 kg COD d–1 m–3) stimulated biomass aggregation, settling, and accumulation in the system, reaching as high as 3.8 g VSS L–1. The sludge retention time (SRT) increased freely from 2.5 to 11 days. Acetate, ammonium, and orthophosphate were removed up to 96% at a rate of 1.1 kg COD d–1 m–3, 77% at 113 g N d–1 m–3, and 73% at 15 g P d–1 m–3, respectively, with COD:N:P assimilation ratio of 100:6.7:0.9 m/m/m. SBR regime shifts sequentially selected for Rhodobacter (90%) under shorter SRT and non-limiting concentration of acetate during reaction phases, for Rhodopseudomonas (70%) under longer SRT and acetate limitation during reaction, and Blastochloris (10%) under higher biomass concentrations, underlying competition for substrate and photons in the PNSB guild. With SBR operations we produced a fast-settling biomass, highly (>90%) enriched in PNSB. A high nutrient removal was achieved by biomass assimilation, reaching the European nutrient discharge limits. We opened further insights on the microbial ecology of PNSB-based processes for water resource recovery. |
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Wos |
000603626100001 |
Publication Date |
2021-06-02 |
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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 |
2296-4185 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
5.7 |
Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: 5.7; 2020 IF: NA |
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Call Number |
UA @ admin @ c:irua:174085 |
Serial |
7921 |
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