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See detailDevelopment of an analytical method to determine the composition of cryolitic baths used in the Hall-Heroult process, by Raman spectroscopy, at 1000°C
Malherbe, Cédric ULg

Doctoral thesis (2013)

Worldwide metallic aluminium production involves the Hall-Héroult process where the metal is electro-deposited from aluminium oxide solubilised in a molten NaF-AlF3-CaF2 mixture at around 950°C. The ... [more ▼]

Worldwide metallic aluminium production involves the Hall-Héroult process where the metal is electro-deposited from aluminium oxide solubilised in a molten NaF-AlF3-CaF2 mixture at around 950°C. The cryolitic melt is conveniently characterised by both the molar NaF/AlF3 ratio and the Al2O3 content. Nowadays the Hall-Héroult process remains the more economically efficient process even if it still suffers from a high consumption of energy. In particular the overvoltage required by the electrolysis is strongly dependent on the melt composition, especially regarding the Al2O3 content. Controlling the industrial baths composition during the process is therefore critical to reduce the energy loss. Unfortunately there is, up to now, no in situ direct analytical method to do so. Considering our experience in the study of such highly corrosive media by Raman spectroscopy, that technique has been applied to directly determine the melt composition. Three sets of reference spectra are considered in this study, each of them recorded with a different setup. The employed setups were developed to reach progressively, at the laboratory scale, a design that is suitable for a plant application. Eventually, a high quality spectrum can be recorded by the top of the melt, in less than 20 seconds. The employed apparatus is found to influence significantly the shape and quality of the spectra, and consequently their involvement in the quantification. A complex digital treatment of the spectral data acquired is necessary because all Raman bands of interest strongly overlap and some are situated close to the Rayleigh decay. Two main quantitative procedures for the melt composition determination are studied. The first one, the AutoAnalysis procedure, developed in the past and adapted here to the new data, gives reliable predictive results for both the NaF/AlF3 molar ratio and the alumina content. They can be determined with an absolute deviation of 0.06 molar ratio unit and 0.5 wt% respectively. However, the intensity normalisation, required for comparing the intensities of different spectra, relies on the Rayleigh decay that is likely to change with the experimental conditions in the plants. In our second quantitative procedure, the NormaAnalysis procedure, the intensity normalisation is based on the equilibria taking place in the melt. Since those equilibria do no differ with the experimental setup, the NormaAnalysis procedure can be imported to the industrial field. The predicted composition is also evaluated with a good precision: the NaF/AlF3 molar ratio and the alumina content can be determined with an absolute deviation of 0.08 cryolitic ratio unit and 0.3 wt% respectively. It is concluded that the composition of the melt can now be determined with our NormaAnalysis procedure, from a single Raman spectrum, recorded with a Raman apparatus exportable for an in situ measurement on the industrial cells. [less ▲]

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See detailDevelopment of an analytical method to determine the cryolitic bath composition by Raman spectroscopy
Malherbe, Cédric ULg; Gilbert, Bernard ULg

Poster (2010, April 23)

Since the end of the nineteenth century, metallic aluminium is produced by electro-deposition from a solution of aluminium oxide in cryolitic melts around 1000°C (Hall-Héroult process). The industrial ... [more ▼]

Since the end of the nineteenth century, metallic aluminium is produced by electro-deposition from a solution of aluminium oxide in cryolitic melts around 1000°C (Hall-Héroult process). The industrial melt is composed mostly of cryolite (Na3AlF6) and AlF3 and is characterized by the molar NaF/AlF3 ratio, named cryolitic ratio (CR). It turns out that the bath composition is critical: for instance, it has been shown that a small change in the Al2O3 content leads to a great change in the overvoltage required for the electrolysis. Therefore controlling the melt composition is very important in order to reduce the energy lost. Unfortunately no in situ analytical method allows studying the composition of the melt yet. Considering our experience in the study of such highly corrosive media by Raman spectroscopy and since the bath spectrum is function of both the CR and the Al2O3 content, we have proposed in the past to apply that technique to the direct determination of the melt composition. Despite the CR could be well evaluated in the lab, experimental problems however made the practical application difficult. The purpose of this presentation will be to show the new results obtained on an updated instrument: - Spectra are recorded in 20 s or less with a higher quality than before. - The previously developed home-made software was adapted to the updated instrument and various spectra analysis procedures are under study. - A procedure to prepare reference samples was also developed taking into account the homogeneity problems that have been met. - The slopes of the alumina calibration curves are depending on the bath CR, in confirmation of our previous results. - The new results are compared with the previous ones. It will be concluded that Raman spectroscopy is indeed becoming a suitable technique for developing an analytical method to determine the composition of industrial cryolitic melts. [less ▲]

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See detailDevelopment of an analytical strategy to measure major selenium-containing species in juvenile turtles (Trachemys scripta scripta) by SAX-HPLC-ICP MS
Far, Johann ULg; Dyc, Christelle; Das, Krishna ULg et al

Poster (2013, July)

Sea turtles are exposed to many environmental elements such as selenium (Se). Sea turtles are listed under the Red List of threatened species by the International Union for Conservation of Nature. It is ... [more ▼]

Sea turtles are exposed to many environmental elements such as selenium (Se). Sea turtles are listed under the Red List of threatened species by the International Union for Conservation of Nature. It is thus mandatory to use low-invasive tissue collection (skin, carapace, blood ) for estimating Se exposure in these highly protected turtles. For this purpose, a biological modal Trachemys scripta scripta (or slider turtle) was selected. For two months, juvenile turtles were dietary exposed to Se by spiking the food with Selenomethionine (SeMet) or Methionine as control groups. Individuals were sacrificed after different time of exposure and tissues (skin, liver, muscle, carapace and blood) collected to perform Se speciation and determine some biological endpoints. An analytical strategy was developed to cope with the very low amount of available sample. It is briefly consisting by reduction, alkylation and proteolysis of the entire freeze-dried tissues followed by sample clean-up using ultra-filtration membrane. Then anion exchange HPLC using salt and pH gradient was developed to prevent the introduction of organic solvents, which cause severe fooling of ICP MS and avoid ultra-trace analyses of sea water in routine analysis. This method successfully achieved the detection and quantification at ppm level of expected species (i.e SeMet, selenocysteine, inorganic Se) and also unknown species but their relative amounts were time and tissues dependent. [less ▲]

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See detailDevelopment of an animal experimental model to study the effects of levonorgestrel on the human endometrium.
Alvarez Gonzalez, Maria-Luz ULg; Galant, C.; Frankenne, F. et al

in Human Reproduction (2009), 24(3), 697-704

BACKGROUND: This study was designed to develop an animal model to test the response of endometrium to local progestin delivery. METHODS: Proliferative human endometrium was subcutaneously grafted in two ... [more ▼]

BACKGROUND: This study was designed to develop an animal model to test the response of endometrium to local progestin delivery. METHODS: Proliferative human endometrium was subcutaneously grafted in two groups of SCID mice that received, 2 days before, a subcutaneous estradiol (E2) pellet and, for half of them, an additional implant of levonorgestrel (LNG). Mice were sacrificed 1, 2, 3 or 4 weeks after endometrial implantation and grafts were histologically analysed. Proliferation, steroid hormone receptors, blood vessels and stromal decidualization in both groups (E2 and LNG) were immunohistologically evaluated and compared with proliferative endometrium and endometrium from women with an LNG intrauterine device. RESULTS: Grafts presented normal morphological endometrial characteristics. The expression of progesterone receptors was significantly decreased in glands and stroma of the LNG group as compared with the E2 group at all times. A significant decrease was also observed in the stromal expression of estrogen receptor- in the LNG group. At 4 weeks, the mean cross-sectional area of vessels was significantly higher after LNG treatment. CONCLUSIONS: These morphological and immunohistochemical characteristics are similar to those observed in women treated with local LNG. This mouse model might facilitate further investigations needed to understand the mechanisms responsible for the breakthrough bleeding frequently observed in progestin users. [less ▲]

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See detailDevelopment of an antidepressant compliance questionnaire
Demyttenaere, K.; Bruffaerts, R.; Albert, Adelin ULg et al

in Acta Psychiatrica Scandinavica (2004), 110(3), 201-207

Objective: The development of the Antidepressant Compliance Questionnaire (ADCQ), assessing patients' attitudes and beliefs on depression and antidepressants. Method: A 51-item questionnaire was applied ... [more ▼]

Objective: The development of the Antidepressant Compliance Questionnaire (ADCQ), assessing patients' attitudes and beliefs on depression and antidepressants. Method: A 51-item questionnaire was applied to 85 psychiatric out-patients with a DSM-IV diagnosis of major depressive disorder (MDD). This data set was used to assess psychometric properties of the ADCQ. The questionnaire was also applied to 272 primary care out-patients with MDD. Results: A principal component analysis revealed four dimensions with good internal consistency and acceptable test-retest reliability: 'perceived doctor-patient relationship', 'preserved autonomy', 'positive beliefs on antidepressants' and 'partner agreement', resulting in a final questionnaire comprising 33-items. Responses were independent from depression severity and patient age. The response patterns of both psychiatric and primary care patients are provided and illustrate the many erroneous beliefs on antidepressants. Conclusion: The ADCQ has good psychometric properties; further investigation should investigate whether this questionnaire is predictive of patient compliance. [less ▲]

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See detailDevelopment of an easy aqueous sol-gel synthesis for large-scale film deposition methods for the manufacture of coated steel with self-cleaning properties
Mahy, Julien ULg; Léonard, Géraldine ULg; Pirard, Sophie ULg et al

Conference (2016, May 20)

In this work, a global process has been developed to produce at a large scale pure TiO2 films deposited on steel in order to get an easy-to-clean surface. This large scale process implies an easy aqueous ... [more ▼]

In this work, a global process has been developed to produce at a large scale pure TiO2 films deposited on steel in order to get an easy-to-clean surface. This large scale process implies an easy aqueous sol-gel process for the synthesis of the TiO2 sol. This synthesis [1] has been simplified to make easier the extrapolation towards an industrial scale. Results of TEM, photocatalytic properties, film hydrophilicity, and texture obtained with the simplified aqueous sol-gel synthesis (IsoP-TiO2 synthesis) show similar properties than those obtained with the standard aqueous sol-gel synthesis of TiO2 developed previously (HAc-TiO2 synthesis [2]). Only XRD patterns were slightly different with the presence of anatase-brookite phases in IsoP-TiO2 synthesis while anatase phase only was observed in HAc-TiO2 synthesis. Both the aqueous sol-gel synthesis of pure TiO2 and the film deposition on steel by roll-coating have been successfully extrapolated to a larger scale. Indeed, the deposition was done on a pilot line, the steel substrate is 25 cm width, and the band length is 800 m. The coating was deposited at line speed ranging from 30 to 120 m.min-1.The photocatalytic activity and the hydrophilicity of the film were found to be unchanged compared to the films produced at a laboratory scale, thus validating the production of an efficient easy-to-clean material. Even if some problems have still to be solved, this study is a hopeful first step in the development of a large scale process for self-cleaning steel production. [1] S. Mahshid, M. Askari, M.S. Ghamsari, J. Mater. Process. Technol. 189 (2007) 296–300 [2] C.M. Malengreaux, S. Douven, D. Poelman, B. Heinrichs, J.R. Bartlett, J. Sol-Gel Sci. Technol. 71 (2014) 557–570 [less ▲]

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See detailDevelopment of an Environmental Information System for Odour using Citizen and Technology Innovative Sensors and Advanced Modelling
Uhrner, Ulrich; Grosso, gioavanna; Romain, Anne-Claude ULg et al

in CEUR Workshop Proceedings (2014), 1322

The challenge of OMNISCIENTIS is to develop a community based odour monitoring and information system to mitigate odour annoyance and to foster citizens’ participation in environmental governance. The ... [more ▼]

The challenge of OMNISCIENTIS is to develop a community based odour monitoring and information system to mitigate odour annoyance and to foster citizens’ participation in environmental governance. The core is an information system collecting various data of odour emissions obtained by electronic noses and other sensors, meteorological conditions and observations by citizens acting as human sensors. A specific odour dispersion model is developed to use all this information and provide immediate feedback to all stakeholders. This work presents the architecture of the environmental information system, some first results from odour monitoring and model development and validation. [less ▲]

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See detailDevelopment Of An Enzymatic Assay For The Determination Of Cellulose Bioavailability In Municipal Solid Waste
Rodriguez, Christian; Hiligsmann, Serge ULg; Ongena, Marc ULg et al

in Biodegradation (2005), 16(5), 415-422

As there is a constant need to assess the biodegradation potential of refuse disposed of in landfills, we have developed a method to evaluate the biodegradability of cellulosic compounds (cellulose and ... [more ▼]

As there is a constant need to assess the biodegradation potential of refuse disposed of in landfills, we have developed a method to evaluate the biodegradability of cellulosic compounds (cellulose and hemicellulose) in municipal solid waste. This test is based on the quantification of monosaccharids released after the hydrolysis of solid waste samples with an optimised enzyme preparation containing commercially available cellulases and hemicellulases. We show that the amounts of monosaccharids could be related to the biodegradability of the cellulosic material contained in the samples. This enzymatic cellulose degradation test was assayed on 26 samples originating from two Belgian landfills and collected at different depths. As results correlated well with those obtained with a classical biochemical methane potential assay, this new and rapid test is sufficiently reliable to evaluate cellulose bioavailability in waste samples. [less ▲]

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See detailDevelopment of an enzyme-linked immunosorbent assay for equine neutrophil elastase measurement in blood: Preliminary application to colic cases.
de la Rebière de Pouyade, Geoffroy ULg; Franck, Thierry ULg; Salciccia, Alexandra ULg et al

in Veterinary immunology and immunopathology (2010)

Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we ... [more ▼]

Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we purified elastase from equine neutrophils by a double step chromatography and obtained a pure protein of 27kDa, 4kDa smaller than the NE 2A previously purified (Scudamore et al., 1993; Dagleish et al., 1999), which was likely to be NE 2B. We developed an ELISA by using two specific polyclonal antibodies obtained from rabbit and guinea pig. The sandwich complex was detected using a secondary antibody conjugated to alkaline phosphatase. The ELISA showed good precision and accuracy, with intra- and inter-assay coefficients of variation below 10% for equine NE concentrations ranging from 1.875 to 60ng/ml. A stable plasma NE value, unaffected by the delay of centrifugation (over 4h), was obtained with plasma from EDTA anticoagulated blood. The mean value (+/-SEM) measured in 37 healthy horses was 32.53+/-4.6ng/ml. NE level in plasma of horses with colic at the time of admission was significantly higher than in healthy horses. Our results indicate that the ELISA technique we developed to measure plasmatic NE is a powerful tool for studying the role of elastase in equine inflammatory disease. In future, the application will be extended to other equine biological fluids. [less ▲]

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See detailDevelopment of an Enzyme-Linked Immunosorbent Assay for Serodiagnosis of Ringworm Infection in Cattle
Bagut, ET; Cambier, Ludivine ULg; Heinen, Marie-Pierre ULg et al

in Clinical and Vaccine Immunology (2013), 20(8), 1150-1154

Detailed reference viewed: 26 (6 ULg)
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See detailDevelopment of an enzyme-linked immunosorbent assay for specific equine neutrophil myeloperoxidase measurement in blood
Franck, Thierry ULg; Grulke, Sigrid ULg; Deby-Dupont, Ginette et al

in Journal of Veterinary Diagnostic Investigation (2005), 17(5), 412-419

Equine inflammatory disease is accompanied by a neutrophil activation resulting in the release of granulocytic enzyme myeloperoxidase (MPO). To measure MPO in horse plasma as marker of neutrophil ... [more ▼]

Equine inflammatory disease is accompanied by a neutrophil activation resulting in the release of granulocytic enzyme myeloperoxidase (MPO). To measure MPO in horse plasma as marker of neutrophil activation, the authors purified equine neutrophil MPO and developed a specific enzyme immunoassay using 2 specific polyclonal antibodies obtained from rabbit (primary antibody) and guinea pig (secondary antibody). The sandwich complex "primary antibody-MPO-secondary antibody" was detected using a goat anti-guinea pig immunoglobulin antibody conjugated to alkaline phosphatase. The enzyme-linked immunosorbent assay (ELISA) showed good precision and accuracy, with intra- and interassay coefficients of variation below 10% for MPO concentrations ranging from 0.78 to 50 ng/ml. A stable plasma MPO value, unaffected by time elapsed between blood collection and centrifugation, was obtained with plasma from EDTA anticoagulated blood. The mean MPO value measured in 38 healthy horses was 181.80 +/- 64.74 ng/ml. In 20 horses suffering from obstruction of the large or small intestine, MPO concentrations measured at the time of arrival at the intensive care unit were significantly higher than mean normal value, ranging from 477.88 to 2,748.13 ng/ml. Work is in progress to apply this MPO ELISA technique to other biological fluids and other equine diseases. [less ▲]

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See detailDevelopment of an Evidence-Based Calibration Methodology Dedicated to Energy Audit of Office Buildings. Part 1: Methodology and Modeling.
Bertagnolio, Stéphane ULg; Andre, Philippe ULg

in Proceedings of the 10th REHVA World Congress - Clima 2010 (2010, May)

1 Introduction To promote improvements in the HVAC installations of existing buildings, the article 9 of the EPBD directive establishes mandatory audits and inspections of air-conditioning systems. The ... [more ▼]

1 Introduction To promote improvements in the HVAC installations of existing buildings, the article 9 of the EPBD directive establishes mandatory audits and inspections of air-conditioning systems. The development of auditing tools and procedures and the training of future auditors are the main objectives of the HARMONAC project launched in 2007. Four audit stages are generally distinguished: benchmarking, inspection, detailed audit and investment grade audit. Answering the questions encountered along the audit process requires some diagnosis, which has to be established on the basis of the very scarce information currently available: technical data contained in as-built files actually available and, generally, very global recordings of energy consumptions. A dynamic hourly building energy simulation (BES) model is being developed in the frame of the HARMONAC project to help the auditor in establishing his diagnosis despite of the lack of data. Two simulation tools dedicated to assist the auditor are developed on the basis of this equation-based BES model: - The first tool is dedicated to a preliminary benchmarking of the installation. - The second tool is used from inspection stage to evaluation of selected energy conservation measures (ECMs). 2 Simulation-based audit methodology The first step of the audit methodology consists in gathering the as-built and utility data, applying a first treatment and analysis method to this data and using the BES model to perform benchmarking. For this benchmarking targeted work, the actual building is coupled to a typical HVAC system whose performances are defined according to EPBD standards. If the benchmarking indicates that potential energy savings should be studied in the building, the calibration-based audit procedure is launched. In the second step, the BES model is integrated in an iterative evidence-based calibration method adapted to audit purposes. The calibration starts directly at the beginning of the inspection, before realizing any additional measurement. This calibration process includes sensitivity and measurement issues, in order to help the auditor identifying critical points and understanding the building operation. Graphical and statistical methods are used in order to quantify and evaluate if the calibrated baseline model satisfies the predefined tolerances. Finally, the calibrated baseline model can be used to evaluate ECMs and savings uncertainty. The development and the implementation of the BES model are presented in this paper. The mains issues of the proposed calibration-based audit methodology are discussed. An example of application of the whole methodology (from benchmarking to evaluation of ECMs) is presented in a companion paper. [less ▲]

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See detailDevelopment of an Evidence-Based Calibration Methodology Dedicated to Energy Audit of Office Buildings. Part 2: Application to a typical office building in Belgium
Andre, Philippe ULg; Fabry, Bertrand ULg; Bertagnolio, Stéphane ULg et al

in Proceedings of the 10th REHVA World Congress - Clima 2010 (2010, May)

The development of specific tools for the audit of air-conditioning systems is described in a companion paper. These developments are carried out in the frame of the HarmonAC project launched in 2007 in ... [more ▼]

The development of specific tools for the audit of air-conditioning systems is described in a companion paper. These developments are carried out in the frame of the HarmonAC project launched in 2007 in order to assist the implementation of the EPBD, article 9. The development of these tools was continously supported by the application to case studies. This paper reports on the application of the tools within an audit procedure applied to a typical office building in Belgium, which is in operation for more than 20 years. The first step of the work consisted in analyzing the current performance of the building which proved to point out a number of problems in the operation of the building. As it is not rarely the case for running office buildings, these problems were due to a lack of commissioning and a progressive decrease of the performances due to a poor management. Application of the first stage “Benchmark” tool to this building led to a very high discrepancy between the measured consumptions and the calculated ones. This appeared mainly for the electricity consumption but also for the gas consumption. Calibration of the simulation tool, mainly by representing more exactly the management of the building and the real internal gains improved the accuracy of the calculations to a large extent. After calibration of the building and HVAC model, the application of a second tool (SimAudit) allowed to evaluate the savings obtained by the implementation of a number of Energy Conservation Opportunities (ECOs). In this case, the dominant ECOs were in relation with the operation of the building: change of schedules, modification of setpoints; implementation of free-cooling strategies; provision of heat recovery and move to reversibility of the chillers. Reasonable estimates of the savings can be obtained following the calibration/simulation process. The paper will highlight some of the most relevant ECOs and provide an order of magnitude for the savings in this kind of building and in a mild climate. [less ▲]

Detailed reference viewed: 101 (17 ULg)