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Document Server@UHasselt (58.026 recursos)

Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.

Dept. Chemistry-Biology-Geology (SBG) - Applied Chemistry

Mostrando recursos 1 - 20 de 423

  1. Biodesulphurized low rank coal: Maritza east lignite and its "humus-like" byproduct

    Gonsalvesh, L.; Marinov, S. P.; Stefanova, M.; Carleer, R.; Yperman, J.
    Bulgarian coal sample from "Maritza East'' lignite deposit, with a significant impact in the total energy supply for the country, is biodesulphurized on laboratory scale. In order to improve the desulphurization effect, sample under study is preliminary chemically treated, i.e. demineralized, depyritized and oxidized. For microbial treatment the microorganism Pseudomonas putida is applied. Maximum total (71.0%), pyritic (90.6%) and organic (49.4%) sulphur desulphurization effects are achieved as a result of combined action of chemical and microbial attacks. The protocol of Maritsa East lignite biotreatment by P. putida bacterial strain persisted on copious washing of the coal. During it, a high...

  2. Selective Desulfurization of Model Diesel Fuel by Carbon Nanoparticles as Adsorbent

    NAVIRI FALLAH, Rahimeh; Azizian, Saeid; REGGERS, Guy; SCHREURS, Sonja; CARLEER, Robert; YPERMAN, Jan
    This work examines the effect of aromatic compounds (naphthalene and 1-methylnaphthalene) on the adsorption of sulfur thiophenic compounds (including benzothiophene, dibenzothiophene, and dimethyldibenzothiophene) from simulated diesel fuel by dispersed carbon nanoparticles (CNPs) in aqueous solution. To evaluate the equilibrium and kinetics of adsorptive desulfurization by synthesized CNPs, two model diesel fuels with 300 ppmw total concentration of sulfur compounds were used in a batch reactor at ambient conditions. The solid CNPs were characterized using FTIR, thermal analysis, elemental analysis, TEM, and surface pH. The equilibrium experimental data were fitted to Langmuir, Freundlich, and Langmuir-Freundlich models to estimate the adsorption parameters....

  3. Charge transfer in the weak driving force limit in blends of MDMO-PPV and dithienylthiazolo[5,4-d]thiazoles towards organic photovoltaics with high V-OC

    Nevil, Nissy; Ling, Yun; Van Mierloo, Sarah; Kesters, Jurgen; Piersimoni, Fortunato; Adriaensens, Peter; Lutsen, Laurence; Vanderzande, Dirk; Manca, Jean; Maes, Wouter; Van Doorslaer, Sabine; Goovaerts, Etienne
    A series of three 5'-aryl-2,5-dithienylthiazolo[5,4-d]thiazole (DTTzTz) semiconducting molecules with different aryl substituents has been investigated as alternative acceptor materials in combination with the donor polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) in order to evaluate the photoinduced charge transfer (CT) efficiency in the resulting blends, designed towards possible application in organic photovoltaics. Photoluminescence quenching together with polaron detection by electron paramagnetic resonance and photoinduced absorption (PIA) demonstrate an increasing charge transfer efficiency when the DTTzTz substituents are varied from thien-2-yl to 4-trifluoromethylphenyl and 4-cyanophenyl groups, correlating well with the increasing acceptor strength in this series of molecules. In line with this observation, there...

  4. Activated carbon by co-pyrolysis and steam activation from particle board and melamine formaldehyde resin

    Vanreppelen, Kenny; Schreurs, Sonja; Carleer, Robert; Yperman, Jan

  5. Characterization of Modification of 193-nm Photoresist by HBr Plasma

    Vereecke, G.; CLAES, Monica; Le, Q. T.; KESTERS, Els; Struyf, H.; CARLEER, Robert; ADRIAENSENS, Peter
    HBr plasma treatments are used to decrease surface line edge roughness (LER) of patterned photoresist (PR). In this work the modification of two 193-nm photoresists by an HBr plasma treatment was characterized by Fourier Transform Infrared (FTIR) spectroscopy, H-1-NMR (Nuclear Magnetic Resonance) and gel permeation chromatography (GPC). PR modification was shown to follow similar schemes as the degradation of poly(methyl methacrylate) (PMMA) by UV light. Beside the cleavage of ester side-groups, this study showed extensive scission of PR chains, which will contribute to LER reduction by increasing PR chains mobility. However chain scission was accompanied by cross-linking, which may put...

  6. Solid State Solubility of Miconazole in Poly[(ethylene glycol)-g-vinyl alcohol] Using Hot-Melt Extrusion

    Litvinov, V. M.; Guns, S.; ADRIAENSENS, Peter; Scholtens, B. J. R.; Quaedflieg, M. P.; CARLEER, Robert; Van den Mooter, G.
    The use of hot-melt extrusion for preparing homogeneous API-excipient mixtures is studied for miconazole-PEG-g-PVA [poly(ethylene glycol) - poly(vinyl alcohol) graft copolymer] solid dispersions with a 5 cm(3) table-top, twin-screw corotating microcompounder (DSM Xplore). Phase behavior of PEG-g-PVA, miscibility of miconazole in PEG-g-PVA and the partitioning of miconazole between PEG and PVA amorphous phases are characterized using a combination of modulated DSC, XRPD, and solid-state H-1 and C-13 NMR methods. The H-1 NMR transverse magnetization relaxation (T-2 relaxation) method is used to analyze the phase composition and molecular mobility of the copolymer. The T-2 relaxation decay of pure PEG-g-PVA can be...

  7. Exposure of Arabidopsis thaliana to excess Zn reveals a Zn-specific oxidative stress signature

    REMANS, Tony; OPDENAKKER, Kelly; Guisez, Yves; CARLEER, Robert; Schat, Henk; VANGRONSVELD, Jaco; CUYPERS, Ann
    Zinc (Zn) is an essential micronutrient for plants, but accumulation of excess Zn causes oxidative stress, even though the element is not redox-active. An oxidative stress signature, consisting of multiple oxidative stress related parameters, is indicative of disturbance of redox homeostasis and signaling, but has not been determined after exposure to excess Zn. To reveal general and Zn-specific effects, changes in oxidative stress related gene expression, enzyme activities and metabolites were determined after 24 h exposure of Arabidopsis thaliana plants to a concentration range of 0, 100,250 or 500 mu M excess ZnSO4, and the oxidative stress signature compared to...

  8. In-line NIR spectroscopy for the understanding of polymer-drug interaction during pharmaceutical hot-melt extrusion

    Saerens, Lien; Dierickx, Lien; Quinten, Thomas; Adriaensens, Peter; Carleer, Robert; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas
    The aim was to evaluate near-infrared spectroscopy for the in-line determination of the drug concentration, the polymer-drug solid-state behaviour and molecular interactions during hot-melt extrusion. Kollidon (R) SR was extruded with varying metoprolol tartrate (MPT) concentrations (20%, 30% and 40%) and monitored using NIR spectroscopy. A PLS model allowed drug concentration determination. The correlation between predicted and real MPT concentrations was good (R-2 = 0.97). The predictive performance of the model was evaluated by the root mean square error of prediction, which was 1.54%. Kollidon (R) SR with 40% MPT was extruded at 105 degrees C and 135 degrees C...

  9. Organic sulphur alterations in biodesulphurized low rank coals

    Gonsalvesh, L.; Marinov, S. P.; Stefanova, M.; Carleer, R.; Yperman, J.
    Two Bulgarian high sulphur coals, i.e. subbutiminious (Pirin) and lignite (Maritza East), and one Turkish lignite (Cayirhan-Beypazari) are biodesulphurized on laboratory scale. Prior to biotreatments coal samples are chemically treated to be demineralized and depyritized. Due to chemical treatments total sulphur desulphurization in the range of 25.3-54.2% is achieved. Inorganic sulphur (pyritic and sulphatic) is mainly attacked. Pyritic sulphur desulphurization varies in the range of 59.6-77.4%. The white rot fungi ""Phanerochaeta chrysosporium" - ME446 and the thermophilic and acidophilic archae "Sulfolobus solfataricus" - ATCC 35091 are the microorganisms applied in the biodesulphurization processes. Better biodesulphurization is attained for coal samples...

  10. Study of the pyrolisis of municipal solid waste for the production of renewable fuels and chemicals

    Velghe, Inge; Carleer, Robert; Yperman, Jan; Schreurs, Sonja
    Pyrolysis experiments of municipal solid waste (MSW) are carried out in a semi-batch reactor under inert nitrogen atmosphere. Slow pyrolysis – characterized by long residence time (2 hours), heating rate of 4°C/min with sand acted as heat transfer medium- is performed at 550°C. Fast pyrolysis - characterized by short residence time (few minutes), high heating rate with sand acted as heat transfer medium- is performed at 450, 480, 510 and 550°C and different input transfer rates (12 or 24g material/min). The pyrolysis products are studied on composition and yield/distribution and investigated for their use as fuel or raw chemical feedstock....

  11. Articular surfaces of the proximal interphalangeal (PIP) joint of the finger, and its proper collateral ligament (PCL) fiber bundles, presented as a crossed four-bar linkage system

    Van Zwieten, Koos Jaap; Schmidt, Klaus P.; Geusens, Piet P.M.M.; De Munter, Stephanie; Kosten, Lauren; Hotterbeekx, An; Lambrichts, Ivo; Lippens, Peter L.; Adriaensens, Peter
    Superficial and deep fiber bundles within the proper collateral ligament (PCL) of the finger's Proximal Inter Phalangeal (P.I.P.) joint(van Zwieten et al., 2011)are clearly visible in High Resolution MRI frontal and sagittal slices. Because these bundles are fully tautened during PIP flexion, and in view of their intercrossing, we could conceive the PIP joint as a crossed 4-bar linkage system. Introducing into this 4-bar linkage model numerical values, obtained after measurements in sagittal HR-MRI slices, allowed us to construct the curvatures of the only two articulating surfaces which can perform PIP flexion by rolling relative to each other without any...

  12. The Effect of Low Concentration of Oxygen on the Removal of Stable Sulfur in Coal

    Bai, Zong-qing; Li, B.; Li, W.; Liu, F.; Yperman, J.
    In this work, several typical organic sulfur model compounds, including thiophenic and dibenzothiophenic sulfur: and one Chinese coal, Wujiaping, with more organic sulfur were pyrolyzed under 1.0% O-2/Helium (He) and the sulfur forms released were detected by on-line mass spectroscopy in order to investigate the effect and the mechanism of low concentration of oxygen on the removal of the stable organic sulfurs in coal in view of model compounds. The results show that the specific peak temperature of sulfur release is decreased during pyrolysis of the stable thiophenic sulfur model compounds under low concentration of oxygen compared to that under...

  13. Economic risk analysis of fast pyrolysis for the valorization of phytoextracting crops

    Kuppens, Tom; Vanreppelen, Kenny; Wami, Welcome; Yperman, Jan; Carleer, Robert; Schreurs, Sonja; Thewys, Theo
    The value of phytoextracting crops (i.e. plants cultivated for soil remediation) depends on the profitability of the sequential investment in a conversion technique aimed at the economic valorization of the plants. However, the net present value (NPV) of an investment in such an innovative technology is risky due to technical and economic uncertainties. Therefore, decision makers want to dispose of information about the probability of a positive NPV, the largest possible loss, and the crucial economic and technical parameters influencing the NPV. This paper maps the variability in the NPV of an investment in fast pyrolysis for the production of...

  14. Economic trade-off between char for active coal and oil for energy from fast pyrolysis of willow cultivated for phytoremediation

    Kuppens, Tom; Vanreppelen, Kenny; Yperman, Jan; Carleer, Robert; Thewys, Theo
    Economic trade-offs exist between the production of biochar and bio-oil from pyrolysis of biomass. The yield of the typical fast pyrolysis products is dependent on the process temperature: maximum oil yields are obtained at temperatures between 500 and 520 °C, while the char yield decreases with temperature. Several valorization opportunities exist for these pyrolysis products: the char can be applied as a source of energy, a soil amendment or a resource for active coal production, whereas pyrolysis oil can be used for the production of heat and/or electricity and chemicals. These valorization routes influence the potential sales prices of the...

  15. Transport of NORM in the port of Antwerp: from megaports to a special purpose measurement methodology

    Pellens, Veerle; Clerckx, Tim; Hulshagen, Leen; Schroeyers, Wouter; Fias, Pascal; Peeters, Tanja; Biermans, Filip; Schreurs, Sonja
    When nuclear inspections are conducted in the port of Antwerp, many alarms are triggered by NORM. This paper presents an overview and preliminary results of a study taking place in the port of Antwerp and at NORM handling companies. The study aims to get an overview of NORM transport in the port of Antwerp, including quantity, destination, dose rates and activity concentrations. Furthermore, a methodology is being developed to obtain an in situ estimation of the activity concentration of material in containment systems typically used in industry (shipping containers and bulk bags). The preliminary results of the assessment of this...

  16. Description of a portable devices developed at SCK center dot CEN for OSL and TL dosimetry

    Genicot, J. L.; Moyaerts, M.; SCHROEYERS, Wouter
    The Expert Group of Radiation Dosimetry and Calibration of the Belgian Nuclear Research Centre (SCK center dot CEN) uses thermoluminescence (TL) dosimetry for more than thirty years for routine measurements and for R&D purposes. In 2002, an experimental device based on the optically stimulated luminescence (OSL) was developed for research. It works with AL(2)O(3):C detectors (TLD-500 & Luxel (TM)) stimulated with a green line generated by a 150 mW Ar+ laser. Since 2008, modular OSL devices have been developed using light emitting diodes (LED) and working with reflection or transmission mode. This paper describes these modules. The characteristics of the...

  17. Interferon-gamma-induced Ca2+-influx in T lymphocytes of Multiple Sclerosis and Rheumatoid Arthritis patients: A complementary mechanism for T cell activation?

    Buntinx, M.; Ameloot, M.; Steels, P.; Janssen, P.; Medaer, R.; Geusens, P.; Raus, J.; Stinissen, P.
    Autoreactive T lymphocytes are considered to play a crucial role in orchestrating an immunopathological cascade that culminates in damage to the myelin sheath, oligodendrocytes and axons in the central nervous system (CNS) of multiple sclerosis (MS) patients. Autoreactive T cells may also initiate a chronic inflammation in the joints of rheumatoid arthritis (RA) patients. However, autoreactive T cells appear to be only a small component of this immune infiltrate. It has been suggested that the majority of T cells are nonspecifically recruited into the CNS of MS patients and into the inflamed joint of RA patients. The mechanisms underlying the...

  18. Promotieonderzoek “Studie van calciumfluxen onder invloed van interferon-gamma in T-lymfocyten van MS-patiënten en controle-personen

    Buntinx, M.; Ameloot, M.; Steels, P.; Medaer, R.; Geusens, P.; Raus, J.; Stinissen, P.
    Uit deze vergelijkende studie blijkt dat de toename van de calciumconcentratie onder invloed van interferon-gamma in T-cellen van MS- en reumapatiënten significant hoger is dan de toename van calcium in de controle-T-cellen. In bijkomende experimenten hebben we het effect van IFN-gamma onderzocht op de groei van MS en RA T-cellen. We stelden vast dat de calciumtoename onder invloed van interferon-gamma alleen, blijkbaar niet groot genoeg is om de T-cellen in een geactiveerde toestand te brengen waarin ze gaan groeien en vermenigvuldigen. We zagen echter wel dat deze IFN-gamma-geactiveerde calciuminflux kan optreden als een bijkomend mechanisme voor de T-cel-activatie in combinatie...

  19. Interferon-gamma-induced Ca2+-influx in T lymphocytes of Multiple Sclerosis and Rheumatoid Arthritis patients: A complementary mechanism for T cell activation?

    Buntinx, Mieke; Ameloot, Marcel; Steels, Paul; Medaer, Robert; Geusens, Piet; Raus, Jef; Stinissen, Piet
    Autoreactive T-lymphocytes are considered to play a crucial role in orchestrating a chronic inflammation in the central nervous system CNS Ž . of multiple sclerosis MS patients and in the joints of rheumatoid Ž . arthritis RA patients. However, it has been suggested that the majority Ž . of T-cells in the immune infiltrate are nonspecifically recruited into the CNS and into the inflamed joint, respectively. Furthermore, several lines of evidence suggest an important role for interferon-g Ž . IFN-g in the pathogenesis of MS and RA. Here, we have studied whether peripheral blood T-cells from patients with autoimmune diseases are more susceptible to activation in the presence...

  20. Study of Ca2+-fluxes in IFN-gamma-exposed T cells of patients with MS and control subjects

    Buntinx, M.; Ameloot, M.; Steels, P.; Medaer, R.; Geusens, P.; Raus, J.; Stinissen, P.
    Multiple Sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system. T-lymphocytes are important mediators in the pathogenesis of MS. Their activity is modulated by a complex network of cytokines, in which interferon-gamma (IFN-gamma) is considered essential. We investigated the presence of an IFN-gamma-activated Ca2+-influx in T-cells of MS patients and control subjects. The study group (n=63) consisted of patients with stable and active RR-MS and CP-MS. Stable and active rheumatoid arthritis (RA) patients, flu patients and normal subjects (NS) were studied as controls. T-cells were isolated from PBMC by removing B cells and monocytes using anti-CD19 and...

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