Tytgat T (2012) Research and development of self-supporting TiO2 foams for removal of VOCs from ambient air. 164 p
Keywords: Doctoral thesis; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
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“X-ray optics for synchrotron-radiation-induced X-ray micro fluorescence at the european synchrotron-radiation facility, Grenoble”. Vincze L, Janssens K, Adams F, Institute of physics conference series , 613 (1993)
Abstract: Different optical designs for generating synchrotron x-ray micro beams suitable for use in an X-ray fluorescence microscope using an ESRF bending magnet X-ray source are compared. Attention is devoted to the spatial and energy distribution of the photons in the micro beam and to the minimum detection limits that are achievable with each alternative optical system.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Quantitative mu-XRF analysis of heterogeneous samples”. Vincze L, Janssens K, Adams F, Jones K, Microbeam Analysis 1995: Proceedings Of The 29th Annual Conference Of The Microbeam Analysis Society , 175 (1995)
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Parameters influencing focussing capabilities of capillary optics”. Vincze L, Janssens K, Adams F, Larsson S, Rindby A, Engstrom P, Microbeam Analysis 1995: Proceedings Of The 29th Annual Conference Of The Microbeam Analysis Society , 161 (1995)
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“A laboratory mu-XRF spectrometer employing capillary optics”. Janssens K, Vekemans B, Rindby A, Vincze L, Adams F, , 159 (1995)
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Nucleation and growth of the Ni5Al3 phase in Ni-Al austenite and martensite”. Schryvers D, Toth L, Ma Y, Tanner L, Journal de physique: 4
T2 –, IIIrd European Symposium on Martensitic Transformations (ESOMAT 94), SEP 14-16, 1994, BARCELONA, SPAIN 5, 299 (1995). http://doi.org/10.1051/jp4:1995246
Abstract: The nucleation and growth mechanisms of Ni5Al3 precipitates and microtwinned plates in B2 austenite and 2M (3R) martensite phases are described on the basis of conventional and high resolution electron microscopy. In the Ni62.5Al37.5 B2 austenite matrix short annealings at 550 degrees C introduce three-pointed star shaped precipitates consisting of twin related parts of different variants of the Ni5Al3 structure. Longer annealings result in plates growing separately from these wings and developing microtwinning in order to accommodate stress built-up at the interfaces with the surrounding matrix. Annealing of Ni65Al35 2M martensite plates induces simple reordering into the Ni5Al3 phase, increasing the fct c/a ratio by about 1%. As a result stracking faults are introduced in the smallest twin variants.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 3
DOI: 10.1051/jp4:1995246
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“Martensitic and related transformations in Ni-Al alloys”. Schryvers D, Journal de physique: 4
T2 –, IIIrd European Symposium on Martensitic Transformations (ESOMAT 94), SEP 14-16, 1994, BARCELONA, SPAIN 5, 225 (1995). http://doi.org/10.1051/jp4:1995235
Abstract: The present paper gives a review of results of recent studies investigating the fundamentals of the martensitic and related phase transformations in Ni-Al. For the former case, the emphasis will be on the microstructure of martensite plates. The latter include the metastable Ni2Al omega-like and stable Ni5Al3 bainitic phases. These phases will be discussed in view of their atomic structure, nucleation, growth and effect on the martensitic transformation. A separate chapter will deal with precursor effects.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 21
DOI: 10.1051/jp4:1995235
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“Synchrotron radiation induced X-ray microfluorescence analysis”. Janssens K, Vincze L, Vekemans B, Aerts A, Adams F, Jones KW, Knöchel A, Microchimica acta
T2 –, 4th Workshop of the European-Microanalysis-Society on Modern, Developments and Applications in Microbeam Analysis, MAY, 1995, ST MALO, FRANCE , 87 (1996)
Abstract: mu-XRF is the microscopic equivalent of the well-established multielement analytical technique. In this paper, after comparing the interaction of X-ray photons, electrons and protons with matter and an introduction to synchrotron rings and microfocussing of X-rays, the instrumentation for mu-XRF is discussed, both for laboratory source and synchrotron based setups and the analytical characteristics of mu-XRF are contrasted to that of other microanalytical techniques, Also, this issue of quantification of mu-XRF data is addressed; the applicability of the method in archeological and geological analysis is illustrated.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The preparation and preliminary characterisation of eight geological MPI-DING reference glasses for in-site microanalysis”. Jochum KP, Dingwell DB, Rocholl A, Janssens K, Vincze L, et al, Geostandards newsletter 24, 87 (2000). http://doi.org/10.1111/J.1751-908X.2000.TB00590.X
Abstract: Eight silicate glasses were prepared by directly fusing and stirring 50-100 g each of basalt, andesite, komatiite, peridotite, rhyolite, and quartz-diorite. These are referred to as MPI-DING glasses and were made for the purpose of providing reference materials for geochemical, in-situ microanalytical work. Results from various analytical techniques indicate that individual glass fragments are well homogenised with respect to major and trace elements at the mu m to mm scale. Heterogeneities due to quench crystallisation of olivine have been observed in small and limited areas of the two komatiitic glasses. In order to obtain concentration values for as many elements as possible, the glasses were analysed by a variety of bulk and microanalytical methods in a number of laboratories. From the analytical data, preliminary reference values for more than sixty elements were calculated. The analytical uncertainties of most elements are estimated to be between 1% and 10%.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1111/J.1751-908X.2000.TB00590.X
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“Composition of aerosols in the marine boundary layer over the seas of the western Russian Arctic”. Shevchenko VP, Lisitzin AP, Kuptzov VM, Van Malderen H, Martin JM, Van Grieken R, Huang WW, Omnia therapeutica. supplemento 39, 142 (1999)
Abstract: During the SPASIBA expedition (Scientific Program on Arctic and Siberian Aquatorium) on board RV “Yakov Smirnitzky” to the Laptev Sea 10 samples of aerosols in the marine boundary layer have been collected by nylon meshes in August-September 1991. The composition of the samples was studied by a combined approach of different analytical techniques (single-particle analysis, instrumental neutron activation analysis, and atomic absorption spectrometry). The mass concentration of coarse (>1 mu m) insoluble fraction of aerosols was from 0.08 to 0.46 mu g/m(3). In all samples remains of land vegetation were found as the main component. The organic carbon content of the aerosols ranged from 23 to 49%. The inorganic part of the samples is represented mainly by alumosilicates and quartz, In all samples anthropogenic fly ash particles were detected, Temporal variations of the element concentrations are caused by various air masses transported to the study area.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Simulation of poly-capillary lenses for coherent and partially coherent x-rays”. Vincze L, Kukhlevsky SV, Janssens K, Proceedings of the Society of Photo-optical Instrumentation Engineers
T2 –, Conference on Advances in Computational Methods for X-Ray and Neutron, Optics, AUG 03-05, 2004, Denver, CO , 81 (2004). http://doi.org/10.1117/12.560740
Abstract: The intensity distributions of the coherent and partially coherent x-rays passed through a poly-capillary lens have been computed at the focal plane. The computations showed that at the appropriate experimental conditions the interference phenomenon does affect the intensity distribution. In the case of the coherent input radiation with the photon energy of 0.1 keV, the interference fringes were observed, while the non-coherent x-ray radiation produced no interference-like intensity distributions.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 6
DOI: 10.1117/12.560740
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“Confocal mu-XRF, mu-XAFS, and mu-XRD studies of sediment from a nuclear waste disposal natural analogue site and fractured granite following a radiotracer migration experiment”. Denecke MA, Janssens K, Brendebach B, de Nolf W, Falkenberg G, Rothe J, Simon R, Somogyi A, Vekemans B, Noseck U, AIP conference proceedings 882, 187 (2007)
Abstract: Combined mu-XRF, mu-XAFS, and mu-XRD investigations of a uranium-rich tertiary sediment, from a nuclear repository natural analogue site, and a fractured granite bore core section after a column tracer experiment using a Np(V) containing cocktail have been performed. Most mu-XRF/mu-XAFS measurements are recorded in a confocal geometry to provide added depth information. The U-rich sediment results show uranium to be present as a tetravalent phosphate and that U(IV) is associated with As(V). Arsenic present is either As(V) or As(0). The As(0) form thin coatings on the surface of pyrite nodules. A hypothesis for the mechanism of uranium immobilization is proposed, where arsenopyrite acted as reductant of ground water dissolved U(VI) leading to precipitation of less soluble U(IV) and thereby forming As(V). Results for the granite sample show the immobilized Np to be tetravalent and associated with facture material.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The non-destructive determination of REE in fossilized bone using synchrotron radiation induced K-line X-ray microfluorescence analysis”. Janssens K, Vincze L, Vekemans B, Williams CT, Radtke M, Haller M, Knöchel A, Fresenius' journal of analytical chemistry 363, 413 (1999). http://doi.org/10.1007/S002160051212
Abstract: The sensitivity and applicability of the synchrotron radiation induced X-ray microfluorescence (mu-SRXRF) spectrometer at the Hamburg synchrotron laboratory Hasylab for the determination of the distribution of trace concentrations of rare-earth elements (REE) in fossilized bone are discussed and critically compared to those of other trace analytical methods such as instrumental neutron activation analysis (INAA) and LAMP-ICPMS (laser ablation microprobe inductively-coupled plasma mass spectrometry). Measurements were carried out on two bone samples from contrasting terrestrial depositional environments at Olduvai Gorge (Tanzania). Results indicate that the microdistribution of the REE in these biological materials is not homogeneous and that the relative abundance of these elements can provide information on the palaeoenvironment during the fossilization process. The heterogeneous distribution of the REE can be determined in a quantitative and completely non-destructive manner provided the concentrations of individual REE are above 10 mu g/g.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S002160051212
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“Characteristics of atomic absorption calibration curves with the transversely heated graphite furnace”. Bencs L, Szakács O, Szoboszlai N, Ajtony Z, Bozsai G, Journal of analytical atomic spectrometry 18, 105 (2003). http://doi.org/10.1039/B208198A
Abstract: Calibration curves with two quasi-linear sections ("double sloping'') were observed for the medium volatile elements, Cr and Cu, with the use of a SIMAA 6000 graphite furnace atomic absorption spectrometer under interrupted internal gas flow conditions. If a standard transversally heated graphite atomizer (THGA) tube was shortened by 0.5 mm at both of its ends, (i.e. the gaps were enlarged between graphite furnace housing and tube ends), a stronger declination of the calibration curves resulted. Elements with fairly high diffusion coefficients (>5.8 cm(2) s(-1)) and with short appearance time of their transients (<0.6 s), such as Cr and Cu, have shown the most characteristic sensitivity drop towards higher concentrations. This anomalous feature could be eliminated in three different ways; (1) by applying end-capped THGA tubes, (2) using mini-flow (50 cm(3) min(-1)) conditions during the atomization stage, and (3) by adding Pd-Mg chemical modifier. For the low volatile Mo and V, the calibration curves had no irregular shape. For Ag, Co, Cr, Cu, Mn and Ni, the mini-flow settings improved the linearity of the calibration curves and extended the upper limit of the linear calibration range by a factor of 1.5-2.0. The irregular characteristic of the analytical curves was interpreted as an increased vapour loss at higher analyte concentrations through the opened ends of the standard THGA tubes. This vapour loss was associated with the significantly diverse expulsion velocities of atoms, caused by the difference in temperature and concentration gradients, when evaporating amounts of analytes with more than one order of magnitude difference.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/B208198A
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“Calculation of the spectral line profile broadening parameter in graphite furnace atomic absorption spectrometry”. Bencs L, Canadian Journal Of Analytical Sciences And Spectroscopy 53, 52 (2008)
Abstract: A polynomial approach is applied for a number of data from the Posener-tables to calculate the values of the intensity distribution function of atomic absorption lines – H(a, 0.726a) – at the tabulated damping-parameter values with an error not worse than 0.044 %. For the resultant H(a, 0.726a) data, the ninth and sixth order polynomials can be fitted according to the damping parameter range of 0-2, and 2-10, respectively, which results in a minimal error of approximation. The derived functions are simply applicable to the calculation of any H(a, 0.726a) value belonging to a damping-parameter of any arbitrarily selected spectral line, implying the influence of Doppler- and Lorentz-broadening. The overall error of the described method is lower than 0.4 %.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Removal of natural organic matter from water by using ion-exchange resins”. Kabsch-Korbutowicz M, Krupinska B, Przemysl chemiczny
T2 –, Scientific and Technical Conference on Water and Wastewater Basis for, Environmental Protection (School of Quality Water 2008), MAY 28-30, 2008, Kolobrzeg, POLAND 87, 473 (2008)
Abstract: Four aq. solns. contg. natural peat components and the water from Odra river were treated with 3 anion-exchange resins (2.5 to 15 cm(3) of resin per 1 dm(3) of the sample) for 5-60 min to remove the org. matter. The process efficiency was detd. by UV absorbance (254 nm) and colour intensity measurements. The treatment resulted in discoloration of the solns. A resin with weak alky, was the most efficient. The degree of removal increased with increasing the resin dose and contact time. The presence of inorg. anions in the soins. contributed to a decrease of process effectivity.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Degradation potential of airborne particulate matter at the Alhambra monument : a Raman spectroscopic and electron probe X-ray microanalysis study”. Potgieter-Vermaak S, Horemans B, Anaf W, Cardell C, Van Grieken R, Journal of Raman spectroscopy 43, 1570 (2012). http://doi.org/10.1002/JRS.4052
Abstract: It is well known that airborne particulate matter (APM) has an impact on our cultural heritage. A limited number of articles have been published on the sequential application of elemental and molecular techniques to estimate the degradation potential of APM in environments of cultural heritage importance, and most of these were concerned with indoor environments. The Alhambra monument (Granada, Spain) represents one of the grandest and finest examples of Islamic art and architecture from the Middle Ages. As part of an air quality investigation, two sets of APM were collected at the Hall of the Ambassadors and characterised to determine its potential degradation profile. These were analysed by means of micro-Raman spectroscopy (MRS) and electron probe microanalysis with X-ray detection (EPXMA). The Raman data indicated the presence of various mixed salts of acidic and/or hygroscopic nature, such as sodium and ammonium nitrates and sulfates, especially in the finer fraction. Automated EPXMA estimated this fraction to be as high as 50%. Apart from the potential chemical attack, the soiling due to carbonaceous matter deposition is a real concern. Soot was identified by MRS and EPXMA in all size fractions, reaching values of up to 55%, and was often intertwined with soluble inorganic salts. Ongoing degradation of the pigments is implicated by the presence of brightly coloured particles. MRS and molar abundance ternary diagrams elicited the chemical structure of individual APM so that the degradation potential could be established.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/JRS.4052
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“Acute changes in pulse pressure in relation to constituents of particulate air pollution in elderly persons”. Jacobs L, Buczyńska A, Walgraeve C, Potgieter-Vermaak S, Van Grieken R, et al, Environmental research 117, 60 (2012). http://doi.org/10.1016/J.ENVRES.2012.05.003
Abstract: An increased pulse pressure (difference between systolic and diastolic blood pressure) suggests aortic stiffening. The objective of this study was to examine the acute effects of both particulate matter (PM) mass and composition on blood pressure, among elderly persons. We carried out a panel study in persons living in elderly homes in Antwerp, Belgium. We recruited 88 non-smoking persons, 70% women with a mean age of 83 years (standard deviation: 5.2). Blood pressure was measured and a blood sample was collected on two time points, which were chosen so that there was an exposure contrast in ambient PM exposure. The elemental content of the collected indoor and outdoor PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) mass concentration was measured. Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) on outdoor PM10 (particulate matter with an aerodynamic diameter <10 μm) were measured. Each interquartile range increase of 20.8 μg/m³ in 24-h mean outdoor PM2.5 was associated with an increase in pulse pressure of 4.0 mmHg (95% confidence interval: 1.86.2), in persons taking antihypertensive medication (n=57), but not in persons not using antihypertensive medication (n=31) (p for interaction: 0.02). Vanadium, iron and nickel contents of PM2.5 were significantly associated with systolic blood pressure and pulse pressure, among persons on antihypertensive medication. Similar results were found for indoor concentrations. Of the oxy-PAHs, chrysene-5,6-dione and benzo[a]pyrene-3,6-dione were significantly associated with increases in systolic blood pressure and pulse pressure. In elderly, pulse pressure was positively associated with acute increases in outdoor and indoor air pollution, among persons taking antihypertensive medication. These results might form a mechanistic pathway linking air pollution as a trigger of cardiovascular events.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.ENVRES.2012.05.003
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“Mineral dust variability in central West Antarctica associated with ozone depletion”. Cataldo, Evangelista H, Simões JC, Godoi RHM, Simmonds I, Hollanda MH, Wainer I, Aquino FE, Van Grieken R, Atmospheric chemistry and physics discussions 12, 12685 (2012). http://doi.org/10.5194/ACPD-12-12685-2012
Abstract: 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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/ACPD-12-12685-2012
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“Micro-Raman and SEM analysis of minerals from the Darhib mine, Egypt”. Gatto Rotondo G, Darchuk L, Swaenen M, Van Grieken R, Journal of analytical sciences, methods and instrumentation 2, 42 (2012). http://doi.org/10.4236/JASMI.2012.21009
Abstract: The Darhib mine is one of the several talc deposits in the Hamata area of southeastern Egypt. Several specimens of minerals coming from this mine were subjected to complementary investigation by micro-Raman spectrometry and scanning electron microscopy. The difficulty in their identification is the appearance of most of them: they are all very small and only visible under the mineral binocular microscope(×10 – ×40). They appear as small crystals in fissures and holes and a visual determination on colour and crystal gives only a guess of what kind of mineral it could be. Therefore, only after analyzing them by micro-Raman and scanning electron microscopy it was possible to identify their structure and they can be divided in three main groups: one is quite generic and several minerals of different species were identified, such as quartz, talc, mottramite and chrysocolla, very common in the talc mine (these ones are Si-based minerals); the other one is constituted by four samples which are Zn and/or Cu rich, which means minerals of the rosasite or aurichalcite groups; the last group is constituted by two samples containing mainly Pb..
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.4236/JASMI.2012.21009
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“Die risikoprofiel van Pb en Cr in stedelike padstof”. Potgieter-Vermaak S, Van Grieken R, Potgieter H, Litnet akademies : 'n joernaal vir die geesteswetenskappe 9, 1 (2012)
Abstract: The risk profile of Cr and Pb in urban road deposited sediment Exponential urbanisation and industrial growth occur on a global scale and result in an ecological burden, of which one important part is pollution. It is well known that the extent of air pollution has escalated over the past two decades in several parts of the world, despite mitigating measures and legislation. Current research points to the fact that air pollution in urban and industrial areas is substantially different from that found in rural areas. Road dust (RD) contributes up to 35% of airborne particulate matter due to resuspension thereof, and poses a health concern due to carcinogenic and toxic components potentially present in the micron-sized fractions. Although literature does report on the concentrations of trace, toxic metals and metalloids present in RD (Hooker and Nathanail 2006), the molecular make-up of particulates generated due to the resuspension of the RD is not well documented. In vitro and animal toxicological studies have confirmed that the chemical composition of inhaled particles plays a major role in its toxic, genotoxic and carcinogenic mechanisms, but the component-specific toxic effects are still not understood. Transition metals binding to air particle matter can result in reactive oxygen species in the human body (particularly in the lungs), and this is a significant risk, especially for vulnerable population groups like elderly people, children and terminally ill patients. The characterisation of the molecular composition of the fine fraction is evidently of importance for public health. During an earlier study, road dust from an inner-city environment in the UK was collected and partially characterised (Barrett e.a. 2010). These same-size fractions were analysed for their elemental concentrations, using X-ray Fluorescence Spectrometry (XRFS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In addition, single-particle analysis was performed on the different fractions by means of Computer Controlled Electron Probe X-ray Micro Analysis (CC-EPXMA) and their molecular structure probed by studying elemental associations. These findings were correlated with Micro Raman Spectroscopy (MRS) results. It was found that the fine fraction (<38 μm) had the highest Pb (238 ppm) and Cr (171 ppm) concentrations. The CC-EPXMA data showed >50% association of Cr-rich particles with Pb and the MRS data showed that the Cr was mostly present as lead chromate and therefore in the Cr(VI) oxidation state. Concentrations of both Pb and Cr decreased substantially (279 (<38 mm) 13 ppm (<1mm); 171 (<38 mm) 91 ppm (<1mm) respectively) in the larger fractions. Apart from rather alarmingly high concentrations of oxidative stressors (Cu, Fe, Mn), the carcinogenic and toxic potential of the inhalable fraction is evident. Preliminary bioaccessibility data indicated that both Cr and Pb are readily
Keywords: A2 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Universal natural shapes : from unifying shape description to simple methods for shape analysis and boundary value problems”. Gielis J, Caratelli D, Fougerolle Y, Ricci PE, Tavkelidze I, Gerats T, PLoS ONE 7, e29324 (2012). http://doi.org/10.1371/JOURNAL.PONE.0029324
Abstract: 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.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1371/JOURNAL.PONE.0029324
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“Self-inhibition can limit biologically enhanced TCE dissolution from a TCE DNAPL”. Haest PJ, Springael D, Seuntjens P, Smolders E, Chemosphere 89, 1369 (2012). http://doi.org/10.1016/J.CHEMOSPHERE.2012.05.097
Abstract: Biodegradation of trichloroethene (TCE) near a Dense Non Aqueous Phase Liquid (DNAPL) can enhance the dissolution rate of the DNAPL by increasing the concentration gradient at the DNAPL-water interface. Two-dimensional flow-through sand boxes containing a ICE DNAPL and inoculated with a TCE dechlorinating consortium were set up to measure this bio-enhanced dissolution under anaerobic conditions. The total mass of TCE and daughter products in the effluent of the biotic boxes was 3-6 fold larger than in the effluent of the abiotic box. However, the mass of daughter products only accounted for 19-55% of the total mass of chlorinated compounds in the effluent, suggesting that bio-enhanced dissolution factors were maximally 1.3-2.2. The enhanced dissolution most likely primarily resulted from variable DNAPL distribution rather than biodegradation. Specific dechlorination rates previously determined in a stirred liquid medium were used in a reactive transport model to identify the rate limiting factors. The model adequately simulated the overall TCE degradation when predicted resident microbial numbers approached observed values and indicated an enhancement factor for TCE dissolution of 1.01. The model shows that dechlorination of TCE in the 20 box was limited due to the short residence time and the self-inhibition of the TCE degradation. A parameter sensitivity analysis predicts that the bio-enhanced dissolution factor for this TCE source zone can only exceed a value of 2 if the TCE self-inhibition is drastically reduced (when a TCE tolerant dehalogenating community is present) or if the DNAPL is located in a low-permeable layer with a small Darcy velocity. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHEMOSPHERE.2012.05.097
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“Component-specific toxic concerns of the inhalable fraction of urban road dust”. Potgieter-Vermaak S, Rotondo G, Novacovic V, Rollins S, Van Grieken R, Environmental geochemistry and health 34, 689 (2012). http://doi.org/10.1007/S10653-012-9488-5
Abstract: Continuous global urbanisation causes an ever-growing ecological footprint of pollution. Road dust (RD), one of these pollutants, poses a health concern due to carcinogenic and toxic components potentially present in the micron-sized fractions. The literature reports on the concentrations of trace, toxic metals and metalloids present in RD (Hooker and Nathanail in Chem Geol 226:340-351, 2006), but the literature on its molecular composition is limited. Recent reports on the bioaccessibility of platinum group metals are also reported (Colombo et al. in Chem Geol 226:340-351, 2008). In vitro and animal toxicological studies confirmed that the chemical composition of inhaled particles plays a major role in its toxic, genotoxic and carcinogenic mechanisms, but the component-specific toxic effects are still not understood. Particle-bound airborne transition metals can also lead to the production of reactive oxygen species in lung tissue; a special concern amongst particularly susceptible cohorts (children and elderly). The characterisation of the molecular composition of the fine fraction is evidently of importance for public health. During a pilot study, partially characterised size-fractioned RD samples (Barrett et al. in Eviron Sci Technol 44:2940-2946, 2010) were analysed for their elemental concentration using X-ray fluorescence spectrometry and inductively coupled plasma mass spectrometry. In addition, separately dispersed particles (200 particles per size fraction) were analysed individually by means of computer-controlled electron probe X-ray micro-analysis (CC-EPXMA) and their molecular structure probed by studying elemental associations. These were correlated with micro-Raman spectroscopy (MRS) results. It was found that the fine fraction (< 38 mu m) had the highest Pb (238 ppm) and Cr (171 ppm) concentrations. The CC-EPXMA data showed > 50 % association of Cr-rich particles with Pb, and the MRS data showed that the Cr was mostly present as lead chromate and therefore in the Cr(VI) oxidation state. Concentrations of both Pb and Cr decreased substantially (279 (< 38 mu m)-13 ppm (< 1 mm); 171 (< 38 mu m)-91 ppm (< 1 mm), respectively) in the larger fractions. Apart from rather alarmingly high concentrations of oxidative stressors (Cu, Fe, Mn), the carcinogenic and toxic potential of the inhalable fraction is evident. Preliminary bioaccessibility data indicated that both Cr and Pb are readily mobilised in artificial lysosomal liquid and up to 19 % of Cr and 47 % of Pb were released.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S10653-012-9488-5
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“A high-order model for accurately simulating the size distribution of ultrafine particles in a traffic tunnel”. Vos PEJ, Nikolova I, Janssen S, Atmospheric environment : an international journal 59, 415 (2012). http://doi.org/10.1016/J.ATMOSENV.2012.05.011
Abstract: We present a computational model for simulating the dispersion of traffic emitted particulate matter inside a road tunnel, with an emphasis on the number concentration of ultrafine particles (UFP). The model primarily calculates the size distribution of the particle number concentration at each location inside the tunnel. The proposed model differs from existing models in the sense that it uses a continuous representation of the size distribution based upon the high-order finite element method and that it solves the governing equations using the state-of-the-art discontinuous Galerkin method. Next to the traditional transport processes, the model also implements the most important aerosol transformation processes such as coagulation, condensation and dry deposition. It is shown that based upon parametrisations found in literature, the process of condensation in a traffic tunnel cannot properly be modelled. Therefore, we present a correction factor that allows for a better parametrisation. The adequate performance of the model is demonstrated by both a verification study and a validation study. For the verification we show that the discretisation error converges consistently while for the validation we compare the modelled results with a suitable set of data from a UFP measurement campaign in a Taiwanese traffic tunnel. The model is shown to correctly simulate the observed behaviour and by applying a statistical model evaluation we demonstrate that the proposed model meets widely accepted air quality model acceptance criteria. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.ATMOSENV.2012.05.011
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“Elaborating the membrane life concept in a full scale hollow-fibers MBR”. Fenu A, De Wilde W, Gaertner M, Weemaes M, de Gueldre G, van de Steene B, Journal of membrane science 421, 349 (2012). http://doi.org/10.1016/J.MEMSCI.2012.08.001
Abstract: The membrane life-time has a strong impact on competitivity and viability of MBRs. This study critically analyzes the membrane life-time concept, approaching it through different assessment methods. A full scale MBR's membrane life-time was assessed on the following: (i) maintaining the permeate flow throughput to the MBR; (ii) the permeability decline; (iii) oxidative aging; (iv) the increase in energy costs; and (v) mechanical aging. The method based on permeability decline provides a membrane life-time estimate up to a theoretical end. It was further elaborated inherently to operations with no long-term flux decline. The increase in operating pressure remains the main end-of-life trigger for deciding when to replace membrane modules. On the contrary, mechanical and permeate flow throughput analysis of the data are not able to provide a clear estimate of the membrane life-time. As for the membrane life-time estimation based on chlorine contact, it was found to be too optimistic. Complete irreversible fouling occurs before maximum contact time with chlorine is reached. At end-of-life operating conditions, the energy consumption raised of 170% due to the reduced flow rate. The cost raise appears high but still affordable. Earlier membrane replacement thus can never be counterbalanced by energy costs saving. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.MEMSCI.2012.08.001
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“Wintertime spatio-temporal variation of ultrafine particles in a Belgian city”. Mishra VK, Kumar P, Van Poppel M, Bleux N, Frijns E, Reggente M, Berghmans P, Int Panis L, Samson R, The science of the total environment 431, 307 (2012). http://doi.org/10.1016/J.SCITOTENV.2012.05.054
Abstract: Simultaneous measurements of ultrafine particles (UFPs) were carried out at four sampling locations situated within a 1 km(2) grid area in a Belgian city, Borgerhout (Antwerp). All sampling sites had different orientation and height of buildings and dissimilar levels of anthropogenic activities (mainly traffic volume). The aims were to investigate: (i) the spatio-temporal variation of UFP within the area, (ii) the effect of wind direction with respect to the volume of traffic on UFP levels, and (iii) the spatial representativeness of the official monitoring station situated in the study area. All sampling sites followed similar diurnal patterns of UFP variation, but effects of local traffic emissions were evident. Wind direction also had a profound influence on UFP concentrations at certain sites. The results indicated a clear influence of local weather conditions and the more dominant effect of traffic volumes. Our analysis indicated that the regional air quality monitoring station represented the other sampling sites in the study area reasonably well; temporal patterns were found to be comparable though the absolute average concentrations showed differences of up to 35%. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.SCITOTENV.2012.05.054
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van der Snickt G (2012) James Ensor's pigments studied by means of portable and synchrotron radiation-based X-ray techniques : evolution, context and degradation. 501 p
Keywords: Doctoral thesis; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Atomic imaging of cage like structures of silicon”. Nistor L, Van Tendeloo G, Amelinckx S, Cros C, Physica status solidi: A: applied research 146, 119 (1994). http://doi.org/10.1002/pssa.2211460111
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 12
DOI: 10.1002/pssa.2211460111
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“Copper oxycarbonates and mercury-based cuprates: promising high Tc superconductors”. Raveau B, Michel C, Hervieu M, Van Tendeloo G, Martin C, Maignan A, Journal of superconductivity 7, 9 (1994). http://doi.org/10.1007/BF00730359
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 6
DOI: 10.1007/BF00730359
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