“Elemental and ionic components of atmospheric aerosols and associated gaseous pollutants in and near Dar es Salaam, Tanzania”. Mmari AG, Potgieter-Vermaak SS, Bencs L, McCrindle RI, Van Grieken R, Atmospheric environment : an international journal 77, 51 (2013). http://doi.org/10.1016/J.ATMOSENV.2013.04.061
Abstract: Elemental and water-soluble ionic compounds (WSICs) of atmospheric aerosols (total suspended particulate TSP) and some gaseous pollutants (SO2, NO2 and O3) from a coastal, semi-urban and rural site in and near Dar es Salaam, Tanzania were investigated during dry and wet seasons of January 2005November 2007. Na+, Ca2+, SO42−, NO3− and Cl− made up the dominant fraction of WSICs during the dry season with average concentrations ranging from non-detectable (n.d.)5.4, 0.262.6, 0.7414.7, 0.41.5 and 1.13.4 μg m−3, respectively, while in the wet season, from n.d. up to 1.7, 1.2, 4.4, 2.1 and 3.0 μg m−3, respectively. The total air concentrations of the detected elements (Al, Si, S, Cl, K, Ca, Fe and Zn) showed seasonal and site-specific variation in the range of 7.526.6 with an average of 14.5 μg m−3. Most of the air concentrations of pollutants were observed to decrease with increasing distance from the coastal site, which is under urban and industrial pollutant emissions. Sulphur and nitrogen oxidation ratios during the dry season ranged from 0.08 to 0.91 and 0.013 to 0.049, respectively, while they were between 0.090.65 and 0.0020.095, respectively, in the wet season. These values indicate the photochemical oxidation of SO2 and a high extent of NO3−formation in the atmosphere. Neutralization ratios revealed the presence of acidic SO42− and NO3− aerosols. Principal component analysis identified sea spray, local combustion, vehicular traffic, biomass burning and re-suspended road dust as dominant sources of aerosols at the studied coastal and semi-urban sites. However, at the rural site, besides sea spray, crustal sources, soil dust re-suspension and long-range transport are the possible origins of suspended particulates.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.ATMOSENV.2013.04.061
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“Benchmark study on algae harvesting with backwashable submerged flat panel membranes”. de Baerdemaeker T, Lemmens B, Dotremont C, Fret J, Roef L, Goiris K, Diels L, Bioresource technology 129, 582 (2013). http://doi.org/10.1016/J.BIORTECH.2012.10.153
Abstract: The feasibility of algae harvesting with submerged flat panel membranes was investigated as pre-concentration step prior to centrifugation. Polishing of the supernatant coming from the centrifuge was evaluated as well. The effect of membrane polymer (polyvinyl chloride [PVC], polyethersulfone polyvinyl-pyrollidone [PES-PVP], poly vinylidene fluoride [PVDF]), pore size (microfiltration [MF], ultrafiltration [UF]), algae cell concentrations and species were investigated at lab-scale. In addition, backwashing as fouling control was compared to standard relaxation. PVDF was the superior polymer, and UF showed better fouling resistance. Backwashing outperformed relaxation in fouling control. The backwashable membranes allowed up to 300% higher fluxes compared to commercial flat panel benchmark (PVC) membranes. Estimations on energy consumption for membrane filtration followed by centrifugation revealed relatively low values of 0.169 kW h/kg of dry weight of algae compared to 0.5 kW h/kg for algae harvesting via classical centrifuge alone. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2012.10.153
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“Measurements of air pollution emission factors for marine transportation in SECA”. Alföldy B, Lööv JB, Lagler F, Bencs L, Horemans B, Van Grieken R, et al, Atmospheric measurement techniques 6, 1777 (2013). http://doi.org/10.5194/AMT-6-1777-2013
Abstract: The chemical composition of the plumes of seagoing ships was measured during a two week long measurement campaign in the port of Rotterdam, Hoek van Holland The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg−1 fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOx and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was determined. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 vs. 30 g kg−1 fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factors. The intercept of the regression line, 4.8 × 1015 (kg fuel)−1, gives the average number of particles formed during the burning of 1 kg zero sulphur content fuel, while the slope, 2 × 1018, provides the average number of particles formed with 1 kg sulphur burnt with the fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that ~144 g of particulate sulphate was emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was ~42 nm.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/AMT-6-1777-2013
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“Atmospheric turbulence triggers pronounced diel pattern in karst carbonate geochemistry”. Roland M, Serrano-Ortiz P, Kowalski AS, Van Grieken R, Janssens IA, et al, Biogeosciences 10, 5009 (2013). http://doi.org/10.5194/BG-10-5009-2013
Abstract: CO2 exchange between terrestrial ecosystems and the atmosphere is key to understanding the feedbacks between climate change and the land surface. In regions with carbonaceous parent material, CO2 exchange patterns occur that cannot be explained by biological processes, such as disproportionate outgassing during the daytime or night-time CO2 uptake during periods when all vegetation is senescent. Neither of these phenomena can be attributed to carbonate weathering reactions, since their CO2 exchange rates are too small. Soil ventilation induced by high atmospheric turbulence is found to explain atypical CO2 exchange between carbonaceous systems and the atmosphere. However, by strongly altering subsurface CO2 concentrations, ventilation can be expected to influence carbonate weathering rates. By imposing ventilation-driven CO2 outgassing in a carbonate weathering model, we show here that carbonate geochemistry is accelerated and does play a surprisingly large role in the observed CO2 exchange pattern of a semi-arid ecosystem. We found that by rapidly depleting soil CO2 during the daytime, ventilation disturbs soil carbonate equilibria and therefore strongly magnifies daytime carbonate precipitation and associated CO2 production. At night, ventilation ceases and the depleted CO2 concentrations increase steadily. Dissolution of carbonate is now enhanced, which consumes CO2 and largely compensates for the enhanced daytime carbonate precipitation. This is why only a relatively small effect on global carbonate weathering rates is to be expected. On the short term, however, ventilation has a drastic effect on synoptic carbonate weathering rates, resulting in a pronounced diel pattern that exacerbates the non-biological behavior of soil-atmosphere CO2 exchanges in dry regions with carbonate soils.
Keywords: A1 Journal article; Plant and Ecosystems (PLECO) – Ecology in a time of change; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/BG-10-5009-2013
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“Study of the early stages of Mn intrusion in corroded glass by means of combined SR FTIR/\muXRF imaging and XANES spectroscopy”. Nuyts G, Cagno S, Hellemans K, Veronesi G, Cotte M, Janssens K, Procedia Chemistry
T2 –, Youth in Conservation of Cultural Heritage Conference (YOCOCU), June 18-20, 2012, University of Antwerp, Antwerp, Belgium , 239 (2013). http://doi.org/10.1016/J.PROCHE.2013.03.030
Abstract: Historical glass, especially medieval glass, can undergo weathering under the influence of time and environmental conditions. The aim of this investigation was to better understand the processes involved in this natural degradation process by studying artificially altered glass samples prepared for the use of evaluation of conservation methods. Non-durable glass sensors produced by the Fraunhofer Institute (type M1.0) were used as a starting material for artificial alteration. These were immersed in acidic (pH = 0, 2, 4) and neutral solutions (1 h – 8 h). In a second stage the glass samples were immersed in a 0.5 M MnCl2 solution (24 h, 48 h and 72 h), allowing intrusion of Mn from the solution into the gel layer. The samples were characterized at different stages with reflectance FTIR spectroscopy, mu XRF mapping and mu XANES. All measurements were carried out at ESRF, beamline ID21. Reflectance FTIR spectroscopy measurements were performed in the 800 4000 cm(-1) range. Cluster analysis of the resulting maps evidenced the rapid growth of the gel layer in strong acidic conditions. The average spectra for each cluster feature show for the original glass a strong Si-O- stretching band between 900 and 1000 cm(-1), whereas the gel layer could be identified by the increasing Si-O-Si bands around 1100 and 1250 cm(-1). mu XRF maps were recorded at different stages of the experiment at energies around the Mn-K edge (6.539 keV) and with a step size of 2 by 2 m. These confirm the leaching of K+ and Ca+2 from the glass and the intrusion of Mn from the solution. Mn was found throughout the entire gel layer, but with a concentration gradient peaking at the surface. XANES point measurements were recorded at various points where Mn was present. No spatial variation was found, but linear combination fitting of the spectra with various Mn reference compounds indicated that Mn2+Mn23+O4 is the main Mn compound in the gel layer, as was hypothesised by Watkinson et al. The standard corroded glass samples studied here can be used for the evaluation of conservation treatments in follow-up experiments. (C) 2013 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility of the IA-CS (Italian Association of Conservation Scientists) and University of Antwerp
Keywords: P1 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 4
DOI: 10.1016/J.PROCHE.2013.03.030
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“Infiltration or indoor sources as determinants of the elemental composition of particulate matter inside a school in Wroclaw, Poland?”.Zwozdziak A, Sowka I, Krupińska B, Zwozdziak J, Nych A, Building and environment 66, 173 (2013). http://doi.org/10.1016/J.BUILDENV.2013.04.023
Abstract: Children's exposure to air pollution requires a focus on air quality in places where they spend most time, e.g. in schools. Therefore, understanding how indoor elemental concentrations relate the outdoor ones is necessary to create healthy indoor school environment. The aims of this study were to examine the elemental composition of particulate matter (PM1, PM2.5, PM10) in the school and also to investigate to what degree indoor elemental concentrations are affected by outdoor air or generated inside the school. The measurements were performed inside and outside the public school building in the centre of the city. It was observed that concentrations of most elements were higher at school than outside. The dominant elements in PM1 both indoors and outdoors were S, Cl, K, and Zn. PM2.5 and PM10 fractions inside the school were clearly enriched in elements of mineral origin, additionally S, Zn, K and Cl were also present in high concentrations both indoors and outdoors. Results suggested that a significant contribution to indoor Zn, Pb and S concentrations in the PM2.5 fraction was from penetration of outdoor air. 88%, 80% and 90% of the observed total variations in indoor concentrations of Zn, Pb, and S were explained by the linear relationship between indoor and outdoor concentrations. The lack of correlation between indoor and outdoor concentrations obtained for Si, Ca, Ti, Sr indicated that these metals were more likely to originate from indoor sources. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.BUILDENV.2013.04.023
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“Field demonstration and evaluation of the passive flux meter on a CAH groundwater plume”. Verreydt G, Annable MD, Kaskassian S, van Keer I, Bronders J, Diels L, Vanderauwera P, Environmental Science and Pollution Research 20, 4621 (2013). http://doi.org/10.1007/S11356-012-1417-8
Abstract: This study comprises the first application of the Passive Flux Meter (PFM) for the measurement of chlorinated aliphatic hydrocarbon (CAH) mass fluxes and Darcy water fluxes in groundwater at a European field site. The PFM was originally developed and applied to measurements near source zones. The focus of the PFM is extended from near source to plume zones. For this purpose, 48 PFMs of 1.4 m length were constructed and installed in eight different monitoring wells in the source and plume zone of a CAH-contaminated field site located in France. The PFMs were retrieved, sampled, and analyzed after 3 to 11 weeks of exposure time, depending on the expected contaminant flux. PFM evaluation criteria include analytical, technical, and practical aspects as well as conditions and applicability. PFM flux data were compared with so-called traditional soil and groundwater concentration data obtained using active sampling methods. The PFMs deliver reasonable results for source as well as plume zones. The limiting factor in the PFM applicability is the exposure time together with the groundwater flux. Measured groundwater velocities at the field site range from 2 to 41 cm/day. Measured contaminant flux data raise up to 13 g/m(2)/day for perchloroethylene in the plume zone. Calculated PFM flux averaged concentration data and traditional concentration data were of similar magnitude for most wells. However, both datasets need to be compared with reservation because of the different sampling nature and time. Two important issues are the PFM tracer loss during installation/extraction and the deviation of the groundwater flow field when passing the monitoring well and PFM. The demonstration of the PFM at a CAH-contaminated field site in Europe confirmed the efficiency of the flux measurement technique for source as well as plume zones. The PFM can be applied without concerns in monitoring wells with European standards. The acquired flux data are of great value for the purpose of site characterization and mass discharge modeling, and can be used in combination with traditional soil and groundwater sampling methods.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE)
DOI: 10.1007/S11356-012-1417-8
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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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“Seasonal trends of atmospheric nitrogen dioxide and sulfur dioxide over North Santa Clara, Cuba”. Alejo D, Morales MC, de la Torre JB, Grau R, Bencs L, Van Grieken R, van Espen P, Sosa D, Nuñez V, Environmental monitoring and assessment 185, 6023 (2013). http://doi.org/10.1007/S10661-012-3003-4
Abstract: Atmospheric nitrogen dioxide (NO2) and sulfur dioxide (SO2) levels were monitored simultaneously by means of Radiello passive samplers at six sites of Santa Clara city, Cuba, in the cold and the warm seasons in 2010. The dissolved ionic forms of NO2 and SO2 as nitrate and sulfite plus sulfate, respectively, were determined by means of ion chromatography. Analysis of NO2 as nitrite was also performed by UVVis spectrophotometry. For NO2, significant t tests show good agreement between the results of IC and UVVis methods. The NO2 and SO2 concentrations peaked in the cold season, while their minimum levels were experienced in the warm season. The pollutant levels do not exceed the maximum allowable limit of the Cuban Standard 39:1999, i.e., 40 μg/m3 and 50 μg/m3 for NO2 and SO2, respectively. The lowest pollutant concentrations obtained in the warm season can be attributed to an increase in their removal via precipitation (scavenging) while to the decreased traffic density and industrial emission during the summer holidays (e.g., July and August).
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S10661-012-3003-4
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“New insight into UO2F2 particulate structure by micro-Raman spectroscopy”. Stefaniak EA, Darchuk L, Sapundjiev D, Kips R, Aregbe Y, Van Grieken R, Journal of molecular structure 1040, 206 (2013). http://doi.org/10.1016/J.MOLSTRUC.2013.02.012
Abstract: Uranyl fluoride particles produced via hydrolysis of uranium hexafluoride have been deposited on different substrates: polished graphite disks, silver foil, stainless steel and gold-coated silicon wafer, and measured with micro-Raman spectroscopy (MRS). All three metallic substrates enhanced the Raman signal delivered by UO2F2 in comparison to graphite. The fundamental stretching of the UO band appeared at 867 cm−1 in case of the graphite substrate, while in case of the others it was shifted to lower frequencies (down to 839 cm−1). All applied metallic substrates showed the expected effect of Raman signal enhancement; however the gold layer appeared to be most effective. Application of new substrates provides more information on the molecular structure of uranyl fluoride precipitation, which is interesting for nuclear safeguards and nuclear environmental analysis.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MOLSTRUC.2013.02.012
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“Indoor air quality of a museum in a subtropical climate : the Oscar Niemeyer museum in Curitiba, Brazil”. Godoi RHM, Carneiro BHB, Paralovo SL, Campos VP, Tavares TM, Evangelista H, Van Grieken R, Godoi AFL, The science of the total environment 452, 314 (2013). http://doi.org/10.1016/J.SCITOTENV.2013.02.070
Abstract: The assessment of damage to indoor cultural heritage, in particular by pollutants, is nowadays a major and growing concern for curators and conservators. Nevertheless, although many museums have been widely investigated in Europe, the effects of particulate matter and gaseous pollutants in museums under tropical and subtropical climates and with different economic realities are still unclear. An important portion of the world's cultural heritage is currently in tropical countries where both human and financial resources for preserving museum collections are limited. Hence, our aim is to assess the damage that can be caused to the artwork by pollution in hot and humid environments, where air quality and microclimatic condition differences can cause deterioration. As a case study, particulate matter as well as gases were collected at the Oscar Niemeyer Museum (MON) in Curitiba, Brazil, where large modern and contemporary works of art are displayed. NO2, SO2, O3, Acetic Acid, Formic Acids and BTEX, in the ambient air, were sampled by means of passive diffusive sampling and their concentrations were determined by IC or GCMS. The particulate matter was collected in bulk form and analyzed with the use of energy dispersive X-ray fluorescence and aethalometer. The chemical compositions of individual particles were quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis. The gaseous and particulate matter levels were then compared with the concentrations obtained for the same pollutants in other museums, located in places with different climates, and with some reference values provided by international cultural heritage conservation centers. Results are interpreted separately and as a whole with the specific aim of identifying compounds that could contribute to the chemical reactions taking place on the surfaces of artifacts and which could potentially cause irreversible damage to the artworks.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.SCITOTENV.2013.02.070
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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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“About “bulky&rdquo, links, generated by generalized Möbius Listing's bodies GML3n”. Tavkhelidze I, Cassisa C, Gielis J, Ricci PE, Matematica e applicazioni : atti della Accademia nazionale dei Lincei 24, 11 (2013). http://doi.org/10.4171/RLM/643
Abstract: In the present paper we consider the “bulky knots'' and ”bulky links'', which appear after cutting a Generalized Möbius Listing's GMLn3 body (whose radial cross section is a plane 3-symmetric figure with three vertices) along different Generalized Möbius Listing's surfaces GMLn2 situated in it. This article is aimed to investigate the number and geometric structure of the independent objects appearing after such a cutting process of GMLn3 bodies. In most cases we are able to count the indices of the resulting mathematical objects according to the known tabulation for Knots and Links of small complexity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.4171/RLM/643
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“Microchemical investigation of bone derived from mice treated with strontium in different chemical forms using scanning electron microscopy and micro-Raman spectroscopy”. Jabłoński MB, Stefaniak EA, Darchuk L, Turzańska K, Gorzelak M, Kuduk R, Dorriné, W, Van Grieken R, Microchemical journal 108, 168 (2013). http://doi.org/10.1016/J.MICROC.2012.10.015
Abstract: We used SEM/EDX and micro-Raman spectroscopy to investigate the chemical changes (both on the level of elementary and molecular composition) of mice bones when strontium is incorporated in their microstructure after being administered in the form of two salts: chloride and ranelate. Strontium accumulated mainly in vicinity of bone edges, both cortical and close to bone marrow. The distribution of other elements comprising bone samples (Ca, P, Mg, K etc.) was also determined by energy-dispersive X-ray analysis (EDX). The area adjacent to a cortical bone edge with accumulated strontium has presented modified Raman spectral profiles. Besides most of the Raman bands typical for both mineral (hydroxyapatite with carbonate substitution type B) and organic phases of a bone, we observed a Raman band at 811 cm− 1. It was detected regularly in the sample with high strontium concentration.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MICROC.2012.10.015
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“Mineral dust variability in central West Antarctica associated with ozone depletion”. Cataldo M, Evangelista H, Simões JC, Godoi RHM, Simmonds I, Hollanda MH, Wainer I, Aquino F, Van Grieken R, Atmospheric chemistry and physics 13, 2165 (2013). http://doi.org/10.5194/ACP-13-2165-2013
Abstract: We present here data of mineral dust variability retrieved from an ice core of the central West Antarctic, spanning the last five decades. Main evidence provided by the geochemical analysis is that northerly air mass incursions to the coring site, tracked by insoluble dust microparticles, have declined over the past 50 yr. This result contrasts with dust records from ice cores reported to the coastal West Antarctic that show increases since mid-20th century. We attribute this difference to regional climatic changes due to the ozone depletion and its implications to westerly winds. We found that the diameters of insoluble microparticles in the central West Antarctica ice core are significantly correlated with cyclone depth (energy) and wind intensity around Antarctica.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/ACP-13-2165-2013
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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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“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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“Identification of heavy metal origins related to chemical and morphological soil properties using several non-destructive X-ray analytical methods”. Akbulut S, Van Grieken R, Kilic MA, Čevik U, Rotondo GG, Environmental monitoring and assessment 185, 2377 (2013). http://doi.org/10.1007/S10661-012-2718-6
Abstract: Soils are complex mixtures of organic, inorganic materials, and metal compounds from anthropogenic sources. In order to identify the pollution sources, their magnitude and development, several X-ray analytical methods were applied in this study. The concentrations of 16 elements were determined in all the soil samples using energy dispersive X-ray fluorescence spectrometry. Soils of unknown origin were observed by scanning electron microscopy equipped with a Si(Li) X-ray detector using Monte Carlo simulation approach. The mineralogical analyses were carried out using X-ray diffraction spectrometry. Due to the correlations between heavy metals and oxide compounds, the samples were analyzed also by electron probe microanalyzer (EPMA) in order to have information about their oxide contents. On the other hand, soil pH and salinity levels were identified owing to their influence between heavy metal and soil-surface chemistry. Moreover, the geoaccumulation index (I geo) enables the assessment of contamination by comparing current and pre-industrial concentrations.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S10661-012-2718-6
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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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“Gross alpha and beta activities of airborne particulate samples from Wawel Royal Castle Museum in Cracow, Poland”. Akbulut S, Krupinska B, Worobiec A, Čevik U, Taskin H, Van Grieken R, Samek L, Wiłkojć, E, Journal of radioanalytical and nuclear chemistry 295, 1567 (2013). http://doi.org/10.1007/S10967-012-1983-8
Abstract: Soils are complex mixtures of organic, inorganic materials, and metal compounds from anthropogenic sources. In order to identify the pollution sources, their magnitude and development, several X-ray analytical methods were applied in this study. The concentrations of 16 elements were determined in all the soil samples using energy dispersive X-ray fluorescence spectrometry. Soils of unknown origin were observed by scanning electron microscopy equipped with a Si(Li) X-ray detector using Monte Carlo simulation approach. The mineralogical analyses were carried out using X-ray diffraction spectrometry. Due to the correlations between heavy metals and oxide compounds, the samples were analyzed also by electron probe microanalyzer (EPMA) in order to have information about their oxide contents. On the other hand, soil pH and salinity levels were identified owing to their influence between heavy metal and soil-surface chemistry. Moreover, the geoaccumulation index (I geo) enables the assessment of contamination by comparing current and pre-industrial concentrations.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
DOI: 10.1007/S10967-012-1983-8
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“Predicting longevity of iron permeable reactive barriers using multiple iron deactivation models”. Carniato L, Schoups G, Seuntjens P, Van Nooten T, Simons Q, Bastiaens L, Journal of contaminant hydrology 142, 93 (2012). http://doi.org/10.1016/J.JCONHYD.2012.08.012
Abstract: In this study we investigate the model uncertainties involved in predicting long-term permeable reactive barrier (PRB) remediation efficiency based on a lab-scale column experiment under accelerated flow conditions. A PRB consisting of 20% iron and 80% sand was simulated in a laboratory-scale column and contaminated groundwater was pumped into the column for approximately 1 year at an average groundwater velocity of 3.7E – 1 m d(-1). Dissolved contaminants (PCE. TCE, cis-DCE, trans-DCE and VC) and inorganic (Ca2+, Fe2+, TIC and pH) concentrations were measured in groundwater sampled at different times and at eight different distances along the column. These measurements were used to calibrate a multi-component reactive transport model, which subsequently provided predictions of long-term PRB efficiency under reduced flow conditions (i.e., groundwater velocity of 1.4E -3 m d(-1)), representative of a field site of interest in this study. Iron reactive surface reduction due to mineral precipitation and iron dissolution was simulated using four different models. All models were able to reasonably well reproduce the column experiment measurements, whereas the extrapolated long-term efficiency under different flow rates was significantly different between the different models. These results highlight significant model uncertainties associated with extrapolating long-term PRB performance based on lab-scale column experiments. These uncertainties should be accounted for at the PRB design phase, and may be reduced by independent experiments and field observations aimed at a better understanding of reactive surface deactivation mechanisms in iron PRBs. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.JCONHYD.2012.08.012
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“Composition and state of alteration of 18th century glass from the Cistercian nunnery of Clairefontaine (Belgium)”. Herremans D, Cagno S, Vincke A, de Clercq W, Janssens K, Proceedings of the Society of Photo-optical Instrumentation Engineers
T2 –, Conference on Integrated Approaches to the Study of Historical Glass, (IASHG), APR 16-17, 2012, Brussels, BELGIUM , 842206 (2012). http://doi.org/10.1117/12.975247
Abstract: An extended set of 18th century glass vessels was analyzed by means of SEM-EDX (major and minor element composition) The fragmented archaeological objects were recovered from a latrine belonging to the early 18th century building phase of the nunnery of Clairefontaine, near Arlon (B). On the basis of typology and decoration, the major part of the vessels could be dated around the middle of the 18th century. Variety in color and weathering of the glass suggest differences in glassmaking recipes and in the composition and origin of raw materials. The results of the analysis show how two main compositional groups constitute about 90% of the analyzed glass set, and these are constituted by potash glass (transparent beakers) and high lime low alkali glass (green bottles). Next to these, a few potash-lime and soda glasses are also found. The type of alteration has also a clear relation with the original glass composition.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1117/12.975247
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“Composition of Facon de Venise glass from early 17th century London in comparison with luxury glass of the same age”. Cagno S, de Raedt I, Jeffries T, Janssens K, Proceedings of the Society of Photo-optical Instrumentation Engineers
T2 –, Conference on Integrated Approaches to the Study of Historical Glass, (IASHG), APR 16-17, 2012, Brussels, BELGIUM , 842205 (2012). http://doi.org/10.1117/12.975212
Abstract: SEM-EDX and LA-ICP-MS analyses were performed on a set of early 17th century London glass fragments. The samples originate from two archaeological sites (Aldgate and Old Broad Street) where glass workshops were active in this period. The great majority of the samples are made of soda glass. Two distinct compositional groups are observed, each typical of one site of provenance. The samples originating from the Old Broad Street excavation feature a silica-soda-lime composition, with a moderate amount of potash. The samples from Aldgate are richer in potassium and feature higher amounts of trace elements such as Rb, Zr and Cu. The distinction between the two groups stems from different flux and silica sources used for glassmaking. A comparison with different European glass compositions of that time reveals no resemblance with genuine Venetian production, yet the composition of the Old Broad Street glass shows a close similarity to that of fragments produced 'a la facon de Venise' in Antwerp at the end of the 16th century. This coincides with historical sources attesting the arrival of glassworkers from the Low Countries in England and suggests that a transfer of technology took place near the turn of the century.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 1
DOI: 10.1117/12.975212
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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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“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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“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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“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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“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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“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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