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“Polar and magnetic layered A-site and rock salt B-site-ordered NaLnFeWO6 (Ln = La, Nd) perovskites”. Retuerto M, Li MR, Ignatov A, Croft M, Ramanujachary KV, Chi S, Hodges JP, Dachraoui W, Hadermann J, Tran TT, Halasyamani PS, Grams CP, Hemberger J, Greenblatt M;, Inorganic chemistry 52, 12482 (2013). http://doi.org/10.1021/ic401491y
Abstract: We have expanded the double perovskite family of materials with the unusual combination of layered order in the A sublattice and rock salt order over the B sublattice to compounds NaLaFeWO6 and NaNdFeWO6. The materials have been synthesized and studied by powder X-ray diffraction, neutron diffraction, electron diffraction, magnetic measurements, X-ray absorption spectroscopy, dielectric measurements, and second harmonic generation. At room temperature, the crystal structures of both compounds can be defined in the noncentrosymmetric monoclinic P2(1) space group resulting from the combination of ordering both in the A and B sublattices, the distortion of the cell due to tilting of the octahedra, and the displacement of certain cations. The magnetic studies show that both compounds are ordered antiferromagnetically below T-N approximate to 25 K for NaLaFeWO6 and at similar to 21 K for NaNdFeWO6. The magnetic structure of NaNdFeWO6 has been solved with a propagation vector k = (1/2 0 1/2) as an antiferromagnetic arrangement of Fe and Nd moments. Although the samples are potential multiferroics, the dielectric measurements do not show a ferroelectric response.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 17
DOI: 10.1021/ic401491y
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“Polar and magnetic Mn2FeMO6 (M=Nb, Ta) with LiNbO3-type structure : high-pressure synthesis”. Li MR, Walker D, Retuerto M, Sarkar T, Hadermann J, Stephens PW, Croft M, Ignatov A, Grams CP, Hemberger J, Nowik I, Halasyamani PS, Tran TT, Mukherjee S, Dasgupta TS, Greenblatt M;, Angewandte Chemie: international edition in English 52, 8406 (2013). http://doi.org/10.1002/anie.201302775
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 11.994
Times cited: 53
DOI: 10.1002/anie.201302775
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“Structural and magnetic phase transitions in the AnBnO3n-2 anion-deficient perovskites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16”. Abakumov AM, Batuk M, Tsirlin AA, Tyablikov OA, Sheptyakov DV, Filimonov DS, Pokholok KV, Zhidal VS, Rozova MG, Antipov EV, Hadermann J, Van Tendeloo G;, Inorganic chemistry 52, 7834 (2013). http://doi.org/10.1021/ic3026667
Abstract: Novel anion-deficient perovskite-based ferrites Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 were synthesized by solid-state reaction in air. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 belong to the perovskite-based AnBnO3n2 homologous series with n = 5 and 6, respectively, with a unit cell related to the perovskite subcell ap as ap√2 × ap × nap√2. Their structures are derived from the perovskite one by slicing it with 1/2[110]p(1̅01)p crystallographic shear (CS) planes. The CS operation results in (1̅01)p-shaped perovskite blocks with a thickness of (n 2) FeO6 octahedra connected to each other through double chains of edge-sharing FeO5 distorted tetragonal pyramids which can adopt two distinct mirror-related configurations. Ordering of chains with a different configuration provides an extra level of structure complexity. Above T ≈ 750 K for Pb2Ba2BiFe5O13 and T ≈ 400 K for Pb1.5Ba2.5Bi2Fe6O16 the chains have a disordered arrangement. On cooling, a second-order structural phase transition to the ordered state occurs in both compounds. Symmetry changes upon phase transition are analyzed using a combination of superspace crystallography and group theory approach. Correlations between the chain ordering pattern and octahedral tilting in the perovskite blocks are discussed. Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16 undergo a transition into an antiferromagnetically (AFM) ordered state, which is characterized by a G-type AFM ordering of the Fe magnetic moments within the perovskite blocks. The AFM perovskite blocks are stacked along the CS planes producing alternating FM and AFM-aligned FeFe pairs. In spite of the apparent frustration of the magnetic coupling between the perovskite blocks, all n = 4, 5, 6 AnFenO3n2 (A = Pb, Bi, Ba) feature robust antiferromagnetism with similar Néel temperatures of 623632 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 10
DOI: 10.1021/ic3026667
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“Synthesis, structure, and transport properties of type-I derived clathrate Ge46-xPxSe8-y (x=15.4(1), y=0-2.65) with diverse host-guest bonding”. Kirsanova MA, Mori T, Maruyama S, Matveeva, Batuk D, Abakumov AM, Gerasimenko AV, Olenev AV, Grin Y, Shevelkov AV, Inorganic chemistry 52, 577 (2013). http://doi.org/10.1021/ic3011025
Abstract: A first clathrate compound with selenium guest atoms, [Ge46-xPx]Se8-y square(y) (x = 15.4(1); y = 0-2.65; square denotes a vacancy), was synthesized as a single-phase and structurally characterized. It crystallizes in the space group Fm (3) over bar with the unit cell parameter a varying from 20.310(2) to 20.406(2) angstrom and corresponding to a 2 x 2 x 2 supercell of a usual clathrate-I structure. The superstructure is formed due to the symmetrical arrangement of the three-bonded framework atoms appearing as a result of the framework transformation of the parent clathrate-I structure. Selenium guest atoms occupy two types of polyhedral cages inside the positively charged framework; all selenium atoms in the larger cages form a single covalent bond with the framework atoms, relating the title compounds to a scanty family of semiclathrates. According to the measurements of electrical resistivity and Seebeck coefficient, [Ge46-xPx]Se8-y square(y) is an n-type semiconductor with E-g = 0.41 eV for x = 15.4(1) and y = 0; it demonstrates the maximal thermoelectric power factor of 2.3 x 10(-5) W K-2 m(-1) at 660 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 14
DOI: 10.1021/ic3011025
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“Cs7Nd11(SeO3)12Cl16 : first noncentrosymmetric structure among alkaline-metal lanthanide selenite halides”. Berdonosov PS, Akselrud L, Prots Y, Abakumov AM, Smet PF, Poelman D, Van Tendeloo G, Dolgikh VA, Inorganic chemistry 52, 3611 (2013). http://doi.org/10.1021/ic301442f
Abstract: Cs7Nd11(SeO3)(12)Cl-16, the complex selenite chloride of cesium and neodymium, was synthesized in the NdOCl-SeO2-CsCl system. The compound has been characterized using single-crystal X-ray diffraction, electron diffraction, transmission electron microscopy, luminescence spectroscopy, and second-harmonic-generation techniques. Cs7Nd11(SeO3)(12)Cl-16 crystallizes in an orthorhombic unit cell with a = 15.911(1) angstrom, b = 15.951(1) angstrom, and c = 25.860(1) angstrom and a noncentrosymmetric space group Pna2(1) (No. 33). The crystal structure of Cs7Nd11(SeO3)(12)Cl-16 can be represented as a stacking of Cs7Nd11(SeO3)(12) lamellas and CsCl-like layers. Because of the layered nature of the Cs7Nd11(SeO3)(12)Cl-16 structure, it features numerous planar defects originating from occasionally missing the CsCl-like layer and violating the perfect stacking of the Cs7Nd11(SeO3)(12)Cl-16 lamellas. Cs7Nd11(SeO3)(12)Cl-16 represents the first example of a noncentrosymmetric structure among alkaline-metal lanthanide selenite halides. Cs7Nd11(SeO3)(12)Cl-16 demonstrates luminescence emission in the near-IR region with reduced efficiency due to a high concentration of Nd3+ ions causing nonradiative cross-relaxation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 10
DOI: 10.1021/ic301442f
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“Wafer-level electrical evaluation of vertical carbon nanotube bundles as a function of growth temperature”. Vereecke B, van der Veen MH, Sugiura M, Kashiwagi Y, Ke X, Cott DJ, Hantschel T, Huyghebaert C, Tökei Z, Japanese journal of applied physics 52, 04cn02 (2013). http://doi.org/10.7567/JJAP.52.04CN02
Abstract: We have evaluated the resistance of carbon nanotubes (CNTs) grown at a CMOS-compatible temperature using a realistic integration scheme. The structural analysis of the CNTs by transmission electron microscopy (TEM) showed that the degree of graphitization decreased significantly when the growth temperature was decreased from 540 to 400 °C. The CNTs were integrated to form 150-nm-diameter vertical interconnects between a TiN layer and Cu metal trenches on 200 mm full wafers. Wafers with CNTs grown at low temperature were found to have a lower single-contact resistance than those produced at high temperatures. Thickness measurements showed that the low contact resistance is a result of small contact height. This height dependence is masking the impact of CNT graphitization quality on resistance. When benchmarking our results with data from the literature, a relationship between resistivity and growth temperature cannot be found for CNT-based vertical interconnects.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.384
Times cited: 5
DOI: 10.7567/JJAP.52.04CN02
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“Formation of metallic mercury during photodegradation/photodarkening of \alpha-HgS : electrochemical evidence”. Anaf W, Janssens K, De Wael K, Angewandte Chemie: international edition in English 52, 12568 (2013). http://doi.org/10.1002/ANIE.201303977
Abstract: Das rote Pigment α-HgS neigt in Gegenwart von Licht und Chloridionen zur Schwärzung. Als Grund für die Zersetzung und Entfärbung werden die Bildung von (schwarzem) β-HgS oder Quecksilbermetall vermutet, doch diese Substanzen wurden noch nicht auf natürlich oder künstlich zersetzter HgS-Farbe nachgewiesen. Elektrochemische Experimente belegen nun die Bildung von Quecksilbermetall in Gegenwart von Licht und Chloridionen.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 11.994
Times cited: 19
DOI: 10.1002/ANIE.201303977
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“Lewis base mediated efficient synthesis and solvation-like host-guest chemistry of covalent organic framework-1”. Kalidindi SB, Wiktor C, Ramakrishnan A, Weßing J, Schneemann A, Van Tendeloo G, Fischer RA, Chemical communications 49, 463 (2013). http://doi.org/10.1039/c2cc37183a
Abstract: N-Lewis base mediated room temperature synthesis of covalent organic frameworks (COFs) starting from a solution of building blocks instead of partially soluble building blocks was developed. This protocol shifts COF synthetic chemistry from sealed tubes to open beakers. Non-conventional inclusion compounds of COF-1 were obtained by vapor phase infiltration of ferrocene and azobenzene, and solvation like effects were established.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 17
DOI: 10.1039/c2cc37183a
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“Crystal structure and magnetic properties of the Cr-doped spiral antiferromagnet BiMnFe2O6”. Batuk D, de Dobbelaere C, Tsirlin AA, Abakumov AM, Hardy A, van Bael MK, Greenblatt M, Hadermann J, Materials research bulletin 48, 2993 (2013). http://doi.org/10.1016/j.materresbull.2013.04.038
Abstract: We report the Cr3+ for Mn3+ substitution in the BiMnFe2O6 structure. The BiCrxMn1-xFe2O6 solid solution is obtained by the solution-gel synthesis technique for the x values up to 0.3. The crystal structure investigation using a combination of X-ray powder diffraction and transmission electron microscopy demonstrates that the compounds retain the parent BiMnFe2O6 structure (for x = 0.3, a = 5.02010(6)angstrom, b = 7.06594(7)angstrom, c = 12.6174(1)angstrom, S.G. Pbcm, R-1 = 0.036, R-p = 0.011) with only a slight decrease in the cell parameters associated with the Cr3+ for Mn3+ substitution. Magnetic susceptibility measurements suggest strong similarities in the magnetic behavior of BiCrxMn1-xFe2O6 (x = 0.2; 0.3) and parent BiMnFe2O6. Only T-N slightly decreases upon Cr doping that indicates a very subtle influence of Cr3+ cations on the magnetic properties at the available substitution rates. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 3
DOI: 10.1016/j.materresbull.2013.04.038
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“Fluorine intercalation in the n=1 and n=2 layered manganites Sr2MnO3.5+x and Sr3Mn2O6”. Sullivan E, Gillie LJ, Hadermann J, Greaves C, Materials research bulletin 48, 1598 (2013). http://doi.org/10.1016/j.materresbull.2012.12.073
Abstract: Fluorine insertion into the oxygen defect superstructure manganite Sr2MnO3.5+x has been shown by transmission electron microscopy (TEM) to result in two levels of fluorination. In the higher fluorine content sections, the fluorine anions displace oxygen anions from their apical positions into the equatorial vacancies, thus destroying the superstructure and reverting to a K2NiF4-type structure (a = 3.8210(1) angstrom and c = 12.686(1) angstrom). Conversely, lower fluorine content sections retain the Sr2MnO3.5+x defect superstructure, crystallising in the P2(1)/c space group. Fluorine intercalation into the reduced double-layer manganite Sr3Mn2O6 occurs in a step-wise fashion according to the general formula Sr3Mn2O6Fy with y = 1, 2, and 3. It is proposed that the y = 1 phase (a = 3.815(1)angstrom, c = 20.29(2) angstrom) is produced by the filling of all the equatorial oxygen vacancies by fluorine atoms whilst the y = 2 phase (a = 3.8222(2) angstrom, c = 21.2435(3)angstrom) has a random distribution of fluorine anions throughout both interstitial rocksalt and equatorial sites. Neutron powder diffraction data suggest that the fully fluorinated y = 3 phase (a = 3.8157(6) angstrom, c = 23.666(4) angstrom) corresponds to the complete occupation of all the equatorial oxygen vacancies and the interstitial sites by intercalated fluorine. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 4
DOI: 10.1016/j.materresbull.2012.12.073
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“Structure and magnetic properties of a new anion-deficient perovskite Pb2Ba2BiFe4ScO13 with crystallographic shear structure”. Batuk M, Tyablikov OA, Tsirlin AA, Kazakov SM, Rozova MG, Pokholok KV, Filimonov DS, Antipov EV, Abakumov AM, Hadermann J, Materials research bulletin 48, 3459 (2013). http://doi.org/10.1016/j.materresbull.2013.05.028
Abstract: Pb2Ba2BiFe4ScO13, a new n = 5 member of the oxygen-deficient perovskite-based A(n)B(n)O(3n-2) homologous series, was synthesized using a solid-state method. The crystal structure of Pb2Ba2BiFe4ScO13 was investigated by a combination of synchrotron X-ray powder diffraction, electron diffraction, high-angle annular dark-field scanning transmission electron microscopy and Mossbauer spectroscopy. At 900 K, it crystallizes in the Ammm space group with the unit cell parameters a = 5.8459(1) angstrom, b = 4.0426(1) angstrom, and c=27.3435(1) angstrom. In the Pb2Ba2BiFe4ScO13 structure, quasi-two-dimensional perovskite blocks are periodically interleaved with 1/2[1 1 0] ((1) over bar 0 1)(p) crystallographic shear (CS) planes. At the CS planes, the corner-sharing FeO6 octahedra are transformed into chains of edge-sharing FeO5 distorted tetragonal pyramids. B-positions of the perovskite blocks between the CS planes are jointly occupied by Fe3+ and Sc3+. The chains of the FeO5 pyramids and (Fe,Sc)O-6 octahedra delimit six-sided tunnels that are occupied by double columns of cations with a lone electron pair (Pb2+). The remaining A-cations (Bi3+, Ba2+) occupy positions in the perovskite block. According to the magnetic susceptibility measurements, Pb2Ba2BiFe4ScO13 is antiferromagnetically ordered below T-N approximate to 350 K. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.446
Times cited: 2
DOI: 10.1016/j.materresbull.2013.05.028
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“Gas purification by nonthermal plasma : a case study of ethylene”. Aerts R, Tu X, Van Gaens W, Whitehead JC, Bogaerts A, Environmental science and technology 47, 6478 (2013). http://doi.org/10.1021/es400405c
Abstract: The destruction of ethylene in a dielectric barrier discharge plasma is investigated by the combination of kinetic modeling and experiments, as a case study for plasma-based gas purification. The influence of the specific energy deposition on the removal efficiency and the selectivity toward CO and CO2 is studied for different concentrations of ethylene. The model allows the identication of the destruction pathway in dry and humid air. The latter is found to be mainly initiated by metastable N2 molecules, but the further destruction steps are dominated by O atoms and OH radicals. Upon increasing air humidity, the removal efficiency drops by ±15% (from 85% to 70%), but the selectivity toward CO and CO2 stays more or less constant at 60% and 22%, respectively. Beside CO and CO2, we also identified acetylene, formaldehyde, and water as byproducts of the destruction process, with concentrations of 1606 ppm, 15033 ppm, and 185 ppm in humid air (with 20% RH), respectively. Finally, we investigated the byproducts generated by the humid air discharge itself, which are the greenhouse gases O3, N2O, and the toxic gas NO2.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.198
Times cited: 56
DOI: 10.1021/es400405c
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“Interaction of O and OH radicals with a simple model system for lipids in the skin barrier : a reactive molecular dynamics investigation for plasma medicine”. Van der Paal J, Aernouts S, van Duin ACT, Neyts EC, Bogaerts A, Journal of physics: D: applied physics 46, 395201 (2013). http://doi.org/10.1088/0022-3727/46/39/395201
Abstract: Plasma medicine has been claimed to provide a novel route to heal wounds and regenerate skin, although very little is currently known about the elementary processes taking place. We carried out a series of ReaxFF-based reactive molecular dynamics simulations to investigate the interaction of O and OH radicals with lipids, more specifically with α-linolenic acid as a model for the free fatty acids present in the upper skin layer. Our calculations predict that the O and OH radicals most typically abstract a H atom from the fatty acids, which can lead to the formation of a conjugated double bond, but also to the incorporation of alcohol or aldehyde groups, thereby increasing the hydrophilic character of the fatty acids and changing the general lipid composition of the skin. Within the limitations of the investigated model, no formation of possibly toxic products was observed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 36
DOI: 10.1088/0022-3727/46/39/395201
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“Kinetic modelling for an atmospheric pressure argon plasma jet in humid air”. Van Gaens W, Bogaerts A, Journal of physics: D: applied physics 46, 275201 (2013). http://doi.org/10.1088/0022-3727/46/27/275201
Abstract: A zero-dimensional, semi-empirical model is used to describe the plasma chemistry in an argon plasma jet flowing into humid air, mimicking the experimental conditions of a setup from the Eindhoven University of Technology. The model provides species density profiles as a function of the position in the plasma jet device and effluent. A reaction chemistry set for an argon/humid air mixture is developed, which considers 84 different species and 1880 reactions. Additionally, we present a reduced chemistry set, useful for higher level computational models. Calculated species density profiles along the plasma jet are shown and the chemical pathways are explained in detail. It is demonstrated that chemically reactive H, N, O and OH radicals are formed in large quantities after the nozzle exit and H2, O2(1Δg), O3, H2O2, NO2, N2O, HNO2 and HNO3 are predominantly formed as 'long living' species. The simulations show that water clustering of positive ions is very important under these conditions. The influence of vibrational excitation on the calculated electron temperature is studied. Finally, the effect of varying gas temperature, flow speed, power density and air humidity on the chemistry is investigated.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 115
DOI: 10.1088/0022-3727/46/27/275201
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“Small-angle X-ray scattering and light scattering study of hybrid nanoparticles composed of thermoresponsive triblock copolymer F127 and thermoresponsive statistical polyoxazolines with hydrophobic moieties”. Bogomolova A, Hruby M, Panek J, Rabyk M, Turner S, Bals S, Steinhart M, Zhigunov A, Sedlacek O, Stepanek P, Filippov SK;, Journal of applied crystallography 46, 1690 (2013). http://doi.org/10.1107/S0021889813027064
Abstract: A combination of new thermoresponsive statistical polyoxazolines, poly[(2-butyl-2-oxazoline)-stat-(2-isopropyl-2-oxazoline)] [pBuOx-co-piPrOx], with different hydrophobic moieties and F127 surfactant as a template system for the creation of thermosensitive nanoparticles for radionuclide delivery has recently been tested [Pánek, Filippov, Hrubý, Rabyk, Bogomolova, Kučka Stěpánek (2012). Macromol. Rapid Commun.33, 16831689]. It was shown that the presence of the thermosensitive F127 triblock copolymer in solution reduces nanoparticle size and polydispersity. This article focuses on a determination of the internal structure and solution properties of the nanoparticles in the temperature range from 288 to 312 K. Here, it is demonstrated that below the cloud point temperature (CPT) the polyoxazolines and F127 form complexes that co-exist in solution with single F127 molecules and large aggregates. When the temperature is raised above the CPT, nanoparticles composed of polyoxazolines and F127 are predominant in solution. These nanoparticles could be described by a spherical shell model. It was found that the molar weight and hydrophobicity of the polymer do not influence the size of the outer radius and only slightly change the inner radius of the nanoparticles. At the same time, molar weight and hydrophobicity did affect the process of nanoparticle formation. In conclusion, poly(2-oxazoline) molecules are fully incorporated inside of F127 micelles, and this result is very promising for the successful application of such systems in radionuclide delivery.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 18
DOI: 10.1107/S0021889813027064
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“Spatially resolved ozone densities and gas temperatures in a time modulated RF driven atmospheric pressure plasma jet : an analysis of the production and destruction mechanisms”. Zhang S, Van Gaens W, van Gessel B, Hofmann S, van Veldhuizen E, Bogaerts A, Bruggeman P, Journal of physics: D: applied physics 46, 205202 (2013). http://doi.org/10.1088/0022-3727/46/20/205202
Abstract: In this work, a time modulated RF driven DBD-like atmospheric pressure plasma jet in Ar + 2%O2, operating at a time averaged power of 6.5 W is investigated. Spatially resolved ozone densities and gas temperatures are obtained by UV absorption and Rayleigh scattering, respectively. Significant gas heating in the core of the plasma up to 700 K is found and at the position of this increased gas temperature a depletion of the ozone density is found. The production and destruction reactions of O3 in the jet effluent as a function of the distance from the nozzle are obtained from a zero-dimensional chemical kinetics model in plug flow mode which considers relevant air chemistry due to air entrainment in the jet fluent. A comparison of the measurements and the models show that the depletion of O3 in the core of the plasma is mainly caused by an enhanced destruction of O3 due to a large atomic oxygen density.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 74
DOI: 10.1088/0022-3727/46/20/205202
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“An analysis of the physiologic parameters of intraoral wear: a review”. Lawson NC, Janyavula S, Çakir D, Burgess JO, Journal Of Physics D-Applied Physics 46, Unsp 404007 (2013). http://doi.org/10.1088/0022-3727/46/40/404007
Abstract: This paper reviews the conditions of in vivo mastication and describes a novel method of measuring in vitro wear. Methods: parameters of intraoral wear are reviewed in this analysis, including chewing force, tooth sliding distance, food abrasivity, saliva lubrication, and antagonist properties. Results: clinical measurement of mastication forces indicates a range of normal forces between 20 and 140 N for a single molar. During the sliding phase of mastication, horizontal movement has been measured between 0.9 and 2.86 mm. In vivo wear occurs by three-body abrasion when food particles are interposed between teeth and by two-body abrasion after food clearance. Analysis of food particles used in wear testing reveals that food particles are softer than enamel and large enough to separate enamel and restoration surfaces and act as a solid lubricant. In two-body wear, saliva acts as a boundary lubricant with a viscosity of 3 cP. Enamel is the most relevant antagonist material for wear testing. The shape of a palatal cusp has been estimated as a 0.6 mm diameter ball and the hardest region of a tooth is its enamel surface. pH values and temperatures have been shown to range between 2-7 and 5-55 degrees C in intraoral fluids, respectively. These intraoral parameters have been used to modify the Alabama wear testing method.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.588
DOI: 10.1088/0022-3727/46/40/404007
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“Polarized-beam high-energy EDXRF in geological samples”. Čevik U, Akbulut S, Makarovska Y, Van Grieken R, Spectroscopy letters 46, 36 (2013). http://doi.org/10.1080/00387010.2012.661015
Abstract: Certified reference materials (NIST 1645, BCR 143, IAEA 7, BCR 141, NIESCRM02, and IAEA 375) were used for determining the performance of a secondary target energy-dispersive X-ray fluorescence (EDXRF) spectrometer, Epsilon 5 (PANalytical, Almelo, the Netherlands). For the evaluation of the EDXRF spectra with polarized-beam high-energy excitation, the WinAxil software package has been applied. The results showed that Epsilon 5, EDXRF spectrometry is favorable for the determination of elemental concentrations in geological samples, but the sample preparation has the largest influence on the precision. However, they presented good agreement with certified values for most of the elements.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1080/00387010.2012.661015
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“A robust evolutionary algorithm for the recovery of rational Gielis curves”. Fougerolle YD, Truchetet F, Demonceaux C, Gielis J, Pattern recognition 46, 2078 (2013). http://doi.org/10.1016/J.PATCOG.2013.01.024
Abstract: 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.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.PATCOG.2013.01.024
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“K2CaV2O7 : a pyrovanadate with a new layered type of structure in the A2BV2O7 family”. Tyutyunnik AP, Slobodin BV, Samigullina RF, Verberck B, Tarakina NV, Journal of the Chemical Society : Dalton transactions 42, 1057 (2013). http://doi.org/10.1039/c2dt31246h
Abstract: The crystal structure of K2CaV2O7 prepared by a conventional solid-state reaction has been solved by a direct method and refined using Rietveld full profile fitting based on X-ray powder diffraction data. This compound crystallises in the triclinic space group (P (1) over bar, Z = 2) with unit cell constants a = 7.1577(1) angstrom, b = 10.5104(2) angstrom, c = 5.8187(1) angstrom, alpha = 106.3368(9)degrees, beta = 106.235(1)degrees, gamma = 71.1375(9)degrees. The structure can be described as infinite undulating CaV2O72- layers parallel to the ac plane, which consist of pairs of edge-sharing CaO6 octahedra connected to each other through V2O7 pyrogroups. The potassium atoms are positioned in two sites between the layers, with a distorted IX-fold coordination of oxygen atoms. The chemical composition obtained from the structural solution was confirmed by energy-dispersive X-ray analysis. The stability of compounds in the family of alkali metal calcium pyrovanadates is discussed based on an analysis of the correlation between anion and cation sizes and theoretical first-principles calculations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.029
Times cited: 3
DOI: 10.1039/c2dt31246h
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“Semi-quantitative analysis of the formation of a calcium oxalate protective layer for monumental limestone using combined micro-XRF and micro-XRPD”. Vanmeert F, Mudronja D, Fazinic S, Janssens K, Tibljas D, X-ray spectrometry 42, 256 (2013). http://doi.org/10.1002/XRS.2486
Abstract: A current method for the protection of cretaceous limestone present in various monuments consists of performing a passivating treatment with ammonium oxalate (AmOx). A calcium oxalate protective layer is formed on the surface and enhances the acid resistance of the stone. The in-depth formation of the calcium oxalate layer was investigated on cross sections by using combined micro X-ray fluorescence and micro X-ray powder diffraction (mu XRF/mu XRPD). XRPD showed the presence of both whewellite and weddellite in the calcite stone matrix. A correction was made for sample misalignment, which was visible in both the fluorescence and the diffraction line measurements. A semi-quantitative analysis was performed on the basis of Klug's equation for a two-phase mixture (the presence of weddellite was neglected) without the need for a known reference sample. By assuming two extreme compositions for a reference weight fraction (1 and 99wt%), it was possible to obtain whewellite concentration profiles, which can be used for comparing the effectiveness of different methods for the application of AmOx to the stone surface and the effect of treatment time and AmOx concentration used. It is shown that for the relative amounts of whewellite formed, the differences due to the assumed weight fractions are smaller than the errors due to sample heterogeneity and preferred orientation. Copyright (c) 2013 John Wiley & Sons, Ltd.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.298
Times cited: 5
DOI: 10.1002/XRS.2486
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“Editorial : award for best X-Ray Spectrometry referee during 2011-2012”. Van Grieken R, X-ray spectrometry 42, 3 (2013). http://doi.org/10.1002/XRS.2428
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2428
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“Editorial : introducing Dr Markowicz as X-Ray Spectrometry's new associate editor for Europe”. Van Grieken R, X-ray spectrometry 42, 175 (2013). http://doi.org/10.1002/XRS.2447
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2447
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“New members of the editorial board of X-ray Spectrometry”. Van Grieken R, X-ray spectrometry 42, 1 (2013). http://doi.org/10.1002/XRS.2431
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/XRS.2431
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“Electron diffraction measurement of the binding rigidity of free-standing graphene”. Kirilenko DA, Technical physics letters 39, 325 (2013). http://doi.org/10.1134/S1063785013040081
Abstract: A method for measuring the binding rigidity of free-standing graphene from the dependence of the short-wavelength spectral range of transverse structural fluctuations of a crystal is proposed. The fluctuation spectrum is measured according to the variation in electron-diffraction patterns derived in a transmission electron microscope while tilting the sample.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.771
Times cited: 3
DOI: 10.1134/S1063785013040081
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“Modeling of the performance of BSCF capillary membranes in four-end and three-end integration mode”. Buysse C, Michielsen B, Middelkoop V, Snijkers F, Buekenhondt A, Kretzschmar J, Lenaerts S, Ceramics international 39, 4113 (2013). http://doi.org/10.1016/J.CERAMINT.2012.10.266
Abstract: Owing to their high surface-to-volume ratio, there has been an increasing research interest in mixed ionic electronic conducting (MIEC) capillary membranes for large-scale high temperature oxygen separation applications. They offer an energy-efficient solution for high temperature combustion processes in oxy-fuel and pre-combustion CO2 capture technologies used in fossil fuel power plants. In order to assess the effectiveness of these membranes in power plant applications, the impact of the geometry of Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) capillaries on their performance in the three-end and four-end integration modes has been investigated and thoroughly discussed. The model's parameters were derived from four-end mode lab-scale experiments using gas-tight, macrovoid free and sulfur-free BSCF capillary membranes that were prepared by a phase-inversion spinning technique. The results of this modeling study revealed that in the four-end mode higher average oxygen fluxes and smaller total membrane areas can be obtained than in the three-end mode. This is due to the higher pO(2) gradient across the membrane wall. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.986
Times cited: 4
DOI: 10.1016/J.CERAMINT.2012.10.266
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“Characterisation of hydrous ferric oxides derived from iron-rich groundwaters and their contribution to the suspended sediment of streams”. Baken S, Sjostedt C, Gustafsson JP, Seuntjens P, Desmet N, De Schutter J, Smolders E, Applied geochemistry 39, 59 (2013). http://doi.org/10.1016/J.APGEOCHEM.2013.09.013
Abstract: When Fe(II) bearing groundwaters surface in streams, particulate authigenic Fe-rich material is produced by oxidation. Such freshly precipitated Fe minerals may be transported as suspended sediment and have a profound impact on the fate of trace metals and nutrients in rivers. The objective of this study was to monitor changes in mineralogy and composition of authigenic material from its source to streams of increasing order. Groundwaters, surface waters, and suspended sediment in streams of different order were sampled in the Kleine Nete catchment (Belgium), a lowland with Fe-rich groundwaters (3.5-53.8 mg Fe/L; pH 6.3-6.9). Fresh authigenic material (>0.45 mu m) was produced by oxidising filtered (<0.45 mu m) groundwater and surface water. This material contained, on average, 44% Fe, and smaller concentrations of C, P, and Ca. Iron EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy showed that the Fe was present as poorly crystalline hydrous ferric oxides with a structure similar to that of ferrihydrite. The Fe concentration in the suspended sediment samples decreased to 36-40% (stream order 2), and further to 18-26% (stream order 4 and 5). Conversely, the concentrations of organic C, Ca, Si, and trace metals increased with increasing stream order, suggesting mixing of authigenic material with suspended sediment from a different source. The Fe speciation in the suspended sediment was similar to that in fresh authigenic material, but more Fe-Fe interactions were observed, i.e. it was increasingly hydrolysed, suggesting ageing reactions. The suspended sediment in the streams of order 4 and 5 is estimated to contain between 31% and 59% of authigenic material, but more data are needed to refine this estimate. The authigenic material is an important sink for P in these streams which may alleviate the eutrophication risk in this catchment. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.APGEOCHEM.2013.09.013
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“Influence of N2 concentration in a CH4/N2 dielectric barrier discharge used for CH4 conversion into H2”. Snoeckx R, Setareh M, Aerts R, Simon P, Maghari A, Bogaerts A, International journal of hydrogen energy 38, 16098 (2013). http://doi.org/10.1016/j.ijhydene.2013.09.136
Abstract: We present a combined study of experimental and computational work for a dielectric barrier discharge (DBD) used for CH4 conversion into H2. More specifically, we investigated the influence of N2 as an impurity (150,000 ppm) and as additive gas (199%) on the CH4 conversion and H2 yield. For this purpose, a zero-dimensional chemical kinetics model is applied to study the plasma chemistry. The calculated conversions and yields for various gas mixing ratios are compared to the obtained experimental values, and good agreement is achieved. The study reveals the significance of the View the MathML source and View the MathML source metastable states for the CH4 conversion into H2, based on a kinetic analysis of the reaction chemistry.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.582
Times cited: 40
DOI: 10.1016/j.ijhydene.2013.09.136
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“Determination of ultimate leakage through rutile TiO2 and tetragonal ZrO2 from ab initio complex band calculations”. Clima S, Kaczer B, Govoreanu B, Popovici M, Swerts J, Verhulst AS, Jurczak M, De Gendt S, Pourtois G, IEEE electron device letters 34, 402 (2013). http://doi.org/10.1109/LED.2013.2238885
Abstract: First-principle complex band structures have been computed for rutile TiO2 and tetragonal ZrO2 insulating materials that are of current technological relevance to dynamic random accessmemorymetal-insulator-metal (MIM) capacitors. From the magnitude of the complex wave vectors in different orientations, the most penetrating orientations have been identified. Tunneling effective masses m(tunnel) have been extracted, are shown to be a crucial parameter for the intrinsic leakage, and are identified to be an important parameter in further scaling of MIM capacitors.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.048
Times cited: 3
DOI: 10.1109/LED.2013.2238885
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“The value of groundwater modeling to support a pump and treat design”. Compernolle T, Van Passel S, Lebbe L, Groundwater monitoring &, remediation 33, 111 (2013). http://doi.org/10.1111/GWMR.12018
Abstract: A wide range of rules, algorithms, and models are available to design an effective pump and treat remediation system. Often, one refers to the effectiveness of the developed pump and treat system to demonstrate how valuable the use of a groundwater model can be. An economic valuation of the groundwater model is usually missing. This study provides a framework that puts the discussion concerning the use of groundwater models in an economic perspective. It is not only demonstrated that a more effective pump and treat system can be designed using a groundwater model, but also the economic implications of using a groundwater model are calculated. A set of economic decision rules is applied to determine the economic value of a groundwater model. It is shown that investing in a groundwater model can be economically worthwhile. The remediation time is reduced, remediation costs are saved and the property can be sold more early. These benefits outweigh the costs of developing a groundwater model, and hence a positive net benefit (NB) is determined.
Keywords: A1 Journal article; Economics
DOI: 10.1111/GWMR.12018
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