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See detailDevelopment of lead-210 measurement in peat using polonium extraction. A procedural comparison
De Vleeschouwer, François; Sikorski, Jarek; Fagel, Nathalie ULg

in Geochronometria (2010)

Two chemical treatments for lead-210 measurement were compared on the sub-surface samples of a core from an ombrotrophic bog from East Belgium. The classical procedure involves a concentrated acid ... [more ▼]

Two chemical treatments for lead-210 measurement were compared on the sub-surface samples of a core from an ombrotrophic bog from East Belgium. The classical procedure involves a concentrated acid extraction of polonium. However, this treatment represents substantial health risks together with unknowns regarding both the degree of cleanliness and the Po extraction rate, and most importantly, is rather time consuming. We developed here an improved procedure involving an ashing step prior to acid extraction. This allows substantial improvements such as: 1/ the use of a relatively small amount of acid compared to the classical procedure and 2/ the substantial reduction of a total sample digestion time. Measurements of 210Pb concentrations were conducted by alpha spectrometry. Results show a good agreement of unsupported 210Pb activity obtained for both procedures, although some unknowns remain concerning the adsorption of 210Po on the plastic test tube, the volatilization of a small amount of ash, or the absorption of alpha particle at the alpha source surface. This however should not affect the 210Pb measurement as all the samples are spiked prior to ashing (i.e. the recoveries are fully monitored). Through this study, we are suggesting researchers to follow this new procedure in order to increase safety, cleanliness, better recovery and substantial time gain. [less ▲]

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See detailDevelopment of Liquid-Flooded Scroll Compressor and Expander Models
Bell, Ian; Lemort, Vincent ULg; Braun, Jim et al

(2008, July)

The Liquid Flooded Ericsson Cooler (LFEC) is a gas refrigeration cycle that uses liquid flooding of both the compressor and the expander to achieve nearly isothermal compression and expansion processes as ... [more ▼]

The Liquid Flooded Ericsson Cooler (LFEC) is a gas refrigeration cycle that uses liquid flooding of both the compressor and the expander to achieve nearly isothermal compression and expansion processes as developed by Hugenroth et al. (2007). Efficiency of the LFEC strongly depends on the efficiencies of the compressor and the expander. It is hoped that the LFEC can be a commercially competitive cooling technology, but for these hopes to be realized, high efficiencies for the compressor and expander must be achieved. In order to optimize the design of the compressor and the expander, comprehensive models of both machines have been developed. Validation of the models and analysis of these machines are presented in two separate papers (Bell et al. 2008, Lemort et al. 2008). The models are mechanistic and allow investigation of the influence of design changes and operating conditions on performance. [less ▲]

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See detailDevelopment of membranar effects in frame beams: experimental and analytical investigations
Demonceau, Jean-François ULg; Luu, Nguyen Nam Hai; Jaspart, Jean-Pierre ULg

in EUROSTEEL 2008, 5th European Conference on Steel and Composite Structures (2008, September)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. According to Eurocodes and some ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. According to Eurocodes and some different other national design codes, the structural integrity of civil engineering structures should be ensured through appropriate measures but, in most of the cases, no precise practical guidelines on how to achieve this goal are provided. A European RFCS project called “Robust structures by joint ductility” has been set up in 2004, for three years, with the aim to provide requirements and practical guidelines allowing to ensure the structural integrity of steel and composite structures under exceptional event through an appropriate robustness. The investigations performed at Liège University, as part of this European project, are mainly dedicated to the exceptional event “Loss of a column in a steel or steel-concrete composite building frame”; the main objective is to develop a simplified analytical procedure to predict the frame response further to a column loss. The development of this simplified procedure is detailed in two complementary PhD theses: the thesis of J.-F. Demonceau and the thesis of H.N.N. Luu. The present paper describes experimental and analytical studies carried out within the first PhD thesis. In particular, a simplified analytical method allowing the prediction of the frame response with account of the membranar effects is described. [less ▲]

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See detailDevelopment of microsatellite markers for the characterisation of Phaeoisariopsis griseola (bean angular leaf spot agent) populations in Central America.
Busogoro, Jean-Pierre; Duterme, Olivier; Lepoivre, Philippe ULg

in Plant Protection Science (2002), 38(Special 1),

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See detailDevelopment of mini scale-down platform based on the response of GFP microbial biosensors
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Poster (2012, May 18)

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor ... [more ▼]

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In our previous works, green fluorescent protein reporters have been used as biosensors of the heterogeneities generated in a two compartment scale-down reactor. As there is a huge variety of available whole cell biosensor to characterize the impact of such heterogeneities at the biological level, there is a need for high-throughput cultivation tools in order to investigate the usefulness of a given microbial biosensor among a library comprising several thousands of clones. This work is based on this statement and aims to investigate the potentialities of a mini scale-down platform. Four green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli: rpoS::gfp, uspA::gfp, csiE::gfp and yciG::gfp. The promoters rpoS and uspA are induced in response to a variety of stresses whereas the two other promoters, csiE and yciG, are supposed to be more specific in front of a glucose limitation. First, the response of these biosensors has been assessed in chemostat reactors. These kinds of experiments allow easier interpretation of responses of stress gene related to a glucose limitation since the extracellular conditions are constants and cells are renewed. Biosensors carrying the csiE and yciG promoters have exhibited an induction in function of the glucose limitation. Secondly, a scale-down platform has been tested with the same biosensors and two kinds of glucose addition mode. This scale-down platform involves high-throughput cultivation tools, i.e. in our case shake flask, equipped with non-invasive optical sensors for the monitoring of the dissolved oxygen profile in front of the glucose addition mode. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. The intermittent addition of glucose induces a slow down at the level of the GFP synthesis, suggesting that temporal accumulation of glucose inhibits the activity of the yciG and csiE promoters. In conclusion, the scale-down platform is able to reproduce the same kind of glucose fluctuations that encounters the cells in large-scale processes but not allows studying the impact of high-cell density culture on gene expression. [less ▲]

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See detailThe development of mirative no wonder-constructions
Brems, Lieselotte ULg; Davidse, Kristin; Matthijs, Lennart

Conference (2012, July)

Detailed reference viewed: 89 (8 ULg)
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See detailThe development of mobility controls
Crutzen, Nathalie ULg; Qian, Wei

Conference (2015, March 26)

Detailed reference viewed: 31 (8 ULg)
See detailDevelopment of molecular tests for simultaneous detection of Erwinias spp infecting potato tubers in Belgium
Moh, Ahoussi Augustin ULg; Roussel, S.; Van mellaert, S. et al

Poster (2005)

Detailed reference viewed: 20 (3 ULg)
See detailDevelopment of molecular tests for the detection of Ilar and latent viruses and Banana Mild Mosaic Virus
Marbot, S.; Reichel, H.; Kummert, J. et al

Conference (2004)

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See detailDevelopment of molecular tests for the detection of ILAR and latent viruses in fruit trees.
Roussel, S.; Kummert, J.; Dutrecq, O. et al

in Communications in Agricultural and Applied Biological Sciences (2004), 69(4), 427-432

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See detailDevelopment of monoclonal antibodies recognizing 7-(2-hydroxyethyl)guanine and imidazole ring-opened 7-(2-hydroxyethyl)guanine.
Young, T. L.; Habraken, Yvette ULg; Ludlum, D. et al

in Carcinogenesis (1990), 11

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See detailDevelopment of Multiaxial Constitutive Relationships for Concrete
Gernay, Thomas ULg

Scientific conference (2011, March 18)

Recent research in structural fire engineering has shown that concrete or composite building structures can develop unexpected modes of strength when subjected to fire. Under certain conditions, a ... [more ▼]

Recent research in structural fire engineering has shown that concrete or composite building structures can develop unexpected modes of strength when subjected to fire. Under certain conditions, a structure will present a robust behavior that can dramatically increase its fire resistance compared to the fire resistance calculated by a predictive approach. An example of such robust behavior is the membrane action that can be developed by a structural slab in fire. However, the numerical simulation of such behaviors requires the development of reliable and accurate multiaxial constitutive relationships for modelling the behavior of concrete. This presentation is based on the work performed by the author during a six month research stay at CEA Saclay, in the team of Alain Millard. The aim of the research stay was to develop a concrete multiaxial model that can be used for the numerical analysis by the finite elements method of concrete structures in fire. To be able to accurately simulate the structural behavior during every phases of a natural fire, the concrete model includes plasticity and damage phenomena. The main features and parameters of the model are presented and its implementation in the softwares SAFIR and CAST3M is briefly discussed. Then, a few applications are given and the presentation ends with a comment on the remaining issues and perspectives. [less ▲]

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See detailDevelopment of multilayered chitosan-based nanofibers
Croisier, Florence ULg; Aqil, Abdelhafid ULg; Detrembleur, Christophe ULg et al

Poster (2009, June 14)

By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method ... [more ▼]

By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method for surface coating, based on electrostatic interactions. It enables the controllable deposition of a variety of polyelectrolytes including synthetic and natural materials, with designable layer structure, defined layer thickness and size. Electrospinning (ESP) allows the fabrication of polymer fibers ranging from nanometers to a few microns in diameter, depending on the polymer characteristics (a.o. molecular weight, solution viscosity and conductivity) and processing conditions (electric potential, distance between syringe-capillary and collection plate, concentration, flow rate). Mats of nanofibers produced by ESP display a very large surface area-to-volume ratio and high porosity with very small pore size. The nanometric scale of electrospun fibers also proves a positive effect on cellular growth, as fiber mats mimic extracellular matrix structure. The association of these two techniques with the use of biocompatible and biodegradable polymers such as chitosan, gives outstanding prospects in the field of biomedical applications, especially for the preparation of wound dressings, artificial skin or tissue engineering scaffolds. In the present study, a charged copolymer, poly(methylmethacrylate-block-methacrylic acid), was added to a poly(ε-caprolactone) or poly(D,L-lactide) solution before electrospinning in order to prepare surface charged nanofibers. Oppositely charged polyelectrolytes – chitosan and poly(styrene sulfonate) or hyaluronic acid – were then alternately deposited on these aliphatic polyester fiber “cores” using LBL method. The aliphatic polyester core was also removed selectively to confirm the growth of a multilayered shell, obtaining hollow fibers. [less ▲]

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See detailDevelopment of multilayered chitosan-based nanofibers for tissue engineering
Croisier, Florence ULg; Aqil, Abdelhafid ULg; Detrembleur, Christophe ULg et al

Conference (2009, June 13)

By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method ... [more ▼]

By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method for surface coating, based on electrostatic interactions. It enables the controllable deposition of a variety of polyelectrolytes including synthetic and natural materials, with designable layer structure, defined layer thickness and size. Electrospinning (ESP) allows the fabrication of polymer fibers ranging from nanometers to a few microns in diameter, depending on the polymer characteristics (a.o. molecular weight, solution viscosity and conductivity) and processing conditions (electric potential, distance between syringe-capillary and collection plate, concentration, flow rate). Mats of nanofibers produced by ESP display a very large surface area-to-volume ratio and high porosity with very small pore size. The nanometric scale of electrospun fibers also proves a positive effect on cellular growth, as fiber mats mimic extracellular matrix structure. The association of these two techniques with the use of biocompatible and biodegradable polymers such as chitosan, gives outstanding prospects in the field of biomedical applications, especially for the preparation of wound dressings, artificial skin or tissue engineering scaffolds. In the present study, a charged copolymer, poly(methylmethacrylate-block-methacrylic acid), was added to a poly(ε-caprolactone) or poly(D,L-lactide) solution before electrospinning in order to prepare surface charged nanofibers. Oppositely charged polyelectrolytes – chitosan and poly(styrene sulfonate) or hyaluronic acid – were then alternately deposited on these aliphatic polyester fiber “cores” using LBL method. The aliphatic polyester core was also removed selectively to confirm the growth of a multilayered shell, obtaining hollow fibers. [less ▲]

Detailed reference viewed: 170 (22 ULg)