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See detailContribution to spectral line formation in moving stellar envelopes - Radiation field and statistical equilibrium equations
Surdej, Jean ULg

in Astronomy and Astrophysics (1977), 60

The escape probability method introduced by Sobolev (1947) is used to derive the mean intensity of the radiation field at any point of an envelope which expands spherically with a positive or negative ... [more ▼]

The escape probability method introduced by Sobolev (1947) is used to derive the mean intensity of the radiation field at any point of an envelope which expands spherically with a positive or negative radial-velocity gradient. When considering outward-decelerating envelopes, an additional contribution to the mean intensity of the radiation field must be taken into account when compared with the results obtained by Castor (1970) in the case of outward-accelerating envelopes. A general discussion of the net radiative rates which populate the levels of an atom relates the problem of spectral-line formation in a moving medium to the one in a transparent atmosphere at rest. Namely, it is shown that dilution effects are expected to play an important role in envelopes where very large velocity gradients occur. [less ▲]

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See detailContribution to the applied territorial intelligence: reasoned catalog of territorial information available on internet and sources in Europe
Devillet, Guénaël ULg; Breuer, Christophe ULg

in International Conference of Territorial Information. Papers on Tools and Methods of Territorial Intelligence. (2009)

This article gives a report on the territorial collection of information for the local actors in the whole of Europe (EU 27). It deals with various sources available in Europe in a centralized and ... [more ▼]

This article gives a report on the territorial collection of information for the local actors in the whole of Europe (EU 27). It deals with various sources available in Europe in a centralized and decentralized way. An inventory was carried out for indicators selected within the framework of the method CATALYSE of confrontation of the populations needs with the services available to answer it. Various examples of information sources for the territories (“observatories”) are also putted forward. The reasoned catalog treats methods of cartographic representation for the various indicators. It also highlights the variability of the indicators definitions according to the European suppliers, and the difficulties of harmonization and use. [less ▲]

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See detailA contribution to the audit of an air-conditinioning system: modelling, simulation and benchmarking
Andre, Philippe ULg; Hannay, Cleide; Hannay, Jules et al

in Building Services Engineering Research & Technology (2008), 29(1), 85-98

This paper intends to show how benchmarks can help in the audit of a HVAC system and how these benchmarks can be generated. The work presented is part of the European ‘AUDITAC’ project. How can an auditor ... [more ▼]

This paper intends to show how benchmarks can help in the audit of a HVAC system and how these benchmarks can be generated. The work presented is part of the European ‘AUDITAC’ project. How can an auditor declare that a given HVAC is ‘consuming too much’? He can’t make any judgment, if not having some reference, i.e. some ‘benchmarks’ available. Focus is given here to cooling regime, but even then, heating cannot be forgotten (for example, the remaining heating demand can be satisfied thanks some recovery on the condensers of the chillers). The dramatic question is: what should be the consumption(s) for such a building, in such a climate, with such occupancy, such internal loads and such actual indoor environment? Better than to look for a (very hypothetical) global weather index, similar to heating degree-days, it seems more rational to run a simulation model on a few thousands of hours, corresponding to one (or to several) cooling season(s). Current performances of simulation tools make this approach very expedient. The climate can then be considered as it is, without any simplification. The main simplification is still welcome on the system (buildingþHVAC) side, in order to get calculation robustness, easy understanding and easy parameter identification. In this perspective, the building has to be subdivided in a very limited number of zones and only a few components of the HVAC system have to be included in the simulation model, with as simple as possible control strategies. [less ▲]

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See detailA contribution to the audit of an air-conditioning system: modeling, simulation and benchmarking
Adam, Christophe; Andre, Philippe ULg; Hannay, Cleide et al

(2006, December)

This paper intends to show how benchmarks can help in the audit of a HVAC system and how these benchmarks can be generated. The work presented is part of the European “AUDITAC” project. How can an auditor ... [more ▼]

This paper intends to show how benchmarks can help in the audit of a HVAC system and how these benchmarks can be generated. The work presented is part of the European “AUDITAC” project. How can an auditor declare that a given HVAC is “consuming too much”? He can’t make any judgment, if not having some reference, i.e. some “benchmarks” available. Focus is given here to cooling regime, but even then, heating cannot be forgotten (for example, the remaining heating demand can be satisfied thanks some recovery on the condensers of the chillers). The dramatic question is: what should be the consumption(s) for such a building, in such a climate, with such occupancy, such internal loads and such actual indoor environment? Better than to look for a (very hypothetical) global weather index, similar to heating degree-days, it seems more rational to run a simulation model on a few thousands of hours, corresponding to one (or to several) cooling season(s). Current performances of simulation tools make this approach very expedient. The climate can then be considered as it is, without any simplification. The main simplification is still welcome on the system (building + HVAC) side, in order to get calculation robustness, easy understanding and easy parameter identification. In this perspective, the building has to be subdivided in a very limited number of zones and only a few components of the HVAC system have to be included in the simulation model, with as simple as possible control strategies. [less ▲]

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See detailContribution to the care of patients suffering from terminal liver failure
Detry, Olivier ULg

Post doctoral thesis (2007)

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See detailContribution to the Characterization of Scroll Machines in Compressor and Expander Modes
Lemort, Vincent ULg

Doctoral thesis (2008)

This thesis contributes to the knowledge and the characterization of scroll machines and their systems. It is based on experimental and modeling works carried out on: a) A hermetic scroll compressor used ... [more ▼]

This thesis contributes to the knowledge and the characterization of scroll machines and their systems. It is based on experimental and modeling works carried out on: a) A hermetic scroll compressor used inside an air-cooled water chiller. b) An oil-free open-drive scroll expander integrated into an Organic Rankine Cycle (ORC) power system. c) Open-drive scroll compressor and expander used in a Liquid Flooded Ericsson Cycle Cooler (LFEC). Such a system uses the liquid flooding of the compressor and of the expander to approach isothermal compression and expansion processes. New semi-empirical models of the scroll compressor and expander were proposed and existing models improved. A deterministic model of the scroll expander was established. The model associates a geometrical description of the machine with a thermodynamic description of the expansion process. This model was validated for the two expanders investigated experimentally. The model validation revealed that the performance of the expanders is mainly affected by the supply pressure drop and by the internal leakages. Using the validated model, parametric studies were carried out to investigate the variation of the performance of both expanders with modification of their design and with the operating parameters. The thesis also investigated the scroll machines from the point of view of their integration into thermal systems. A first experimental investigation was carried out on an air-cooled chiller. The scroll compressor semi-empirical model, with its parameters identified on the basis of published manufacturer data, was used as a refrigerant flow meter. The analysis of the experimental data allowed a better understanding of the chiller operation and a better identification of its model parameters (such as the fan and the hot gas bypass control models). A second experimental investigation was carried out on an ORC power system, working with R123. In order to select the most appropriate fluid, the performances achieved with four different fluids were compared by simulation. The experimental study confirmed that the scroll expander is a good candidate for an ORC system: the tested prototype presented a good performance (the maximum global isentropic effectiveness achieved was 68%). Using an ORC simulation model, parametric studies were carried out to investigate the effects of the expander characteristics and operating conditions on the cycle performance. The latter is mainly affected by the expander internal leakage and by the liquid subcooling at the condenser exhaust. A third experimental investigation was performed on a LFEC working with nitrogen as refrigerant and alkyl-benzene oil as flooding liquid. Experimental data was used to identify the parameters of the scroll compressor and expander semi-empirical models. Parametric studies were performed to identify the different factors affecting their performance. One of the undesirable features of the machines is the increase of the supply and exhaust pressure drops with the increase of oil quantity. [less ▲]

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See detailContribution to the derivation of robustness requirements for steel and composite structures
Jaspart, Jean-Pierre ULg; Demonceau, Jean-François ULg

in Proceedings of Advances in steel structures Conference (2007, December)

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See detailContribution to the description of the nitrogen cycle in Lake Kivu
Roland, Fleur ULg; Borges, Alberto ULg; Crowe, Sean et al

Poster (2013, November 12)

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See detailContribution to the design of braced frames with semi-rigid connections
Maquoi, René ULg; Jaspart, Jean-Pierre ULg

in Proceedings of the Fourth International colloquium on stability of metal structures, North America session (1989)

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See detailContribution to the design of sway composite frames
Maquoi, René ULg; Jaspart, Jean-Pierre ULg; Demonceau, Jean-François ULg

in Leon, Roberto; Lange, Jörg (Eds.) Composite Construction in Steel and Concrete V (2004, July 18)

This paper presents numerical and analytical studies carried out at Liège University, as part of a European research project, with the objective to investigate the in-plane behaviour of composite sway ... [more ▼]

This paper presents numerical and analytical studies carried out at Liège University, as part of a European research project, with the objective to investigate the in-plane behaviour of composite sway frames under static loading. [less ▲]

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See detailContribution to the development of a biological control method against crown rot banana disease
Lassois, Ludivine ULg; de Lapeyre de Bellaire, Luc; Jijakli, Haissam ULg et al

Poster (2004)

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See detailContribution to the development of an erosivity index adapted to the prediction of erosion in Belgium
Sinzot, Anne; Bolline, Arthur; Laurant, Adrien et al

in Earth Surface Processes & Landforms (1989), 14

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See detailContribution to the epidemiology of bovine brucellosis in Ivory Coast
Sanogo, Moussa ULg

Doctoral thesis (2014)

Bovine brucellosis is an endemic infectious disease which can negatively impact on cattle productivity and welfare as well as on human health. In many developing countries such as Ivory Coast, there is a ... [more ▼]

Bovine brucellosis is an endemic infectious disease which can negatively impact on cattle productivity and welfare as well as on human health. In many developing countries such as Ivory Coast, there is a need for knowledge on the distribution and the frequency of the disease (or evidence of its presence) within the animal population and the possible factors associated with the disease. Information is also needed on species and biovars of Brucella at national and regional scales, on the performance of commonly used diagnostic tests for accurate estimation of the true disease prevalence, and on determination of risk factors associated with the disease. These informations are of key importance to set up and implement appropriate and efficient prevention and control measures against brucellosis. For these reasons, the research presented in this thesis aimed to contribute to a better understanding of the epidemiology of bovine brucellosis in Ivory Coast. The thesis is structured into three main parts. The introduction part includes three chapters. The first chapter presents an overview of the literature on the pathogen causing brucellosis, their characteristics and distribution. The impact and the existing strategies for preventing and controlling brucellosis are discussed with a particular reference to the situation of bovine brucellosis in Ivory Coast. The presence and the importance of the disease were confirmed in the country but the disease is still uncontrolled. In the second chapter (Chapter 2), an insight on statistical, epidemiological principles and concepts applied to achieve the different objectives (Chapter 3) is given, including a discussion on available approaches to estimate diagnostic test characteristics and the true prevalence of a disease. The second part of the thesis includes research on different aspects of the epidemiology of bovine brucellosis in Ivory Coast and West Africa (Chapter 4, 5, 6 and 7). Chapter 4 specifically provides a state-of–the-art knowledge on species and biovars of Brucella reported in cattle from Ivory Coast and all other countries of West Africa, through a review of available literature. From the synthesized literature, Brucella abortus was demonstrated to be the most prevalent species in cattle in West Africa, in line with the known host preference for Brucellae. So far, biovars 3 appeared to be commonly the most isolated in West Africa and was also recently identified in Ivory Coast. However, the presence of B. melitensis and/or B. suis was not reported yet in cattle in this part of Africa. Results on prevailing strains of Brucella in cattle were related with commonly used serological diagnostic tools. Thus, chapter 5 was dedicated to verify their appropriateness and to assess the performance of two serological tests, Rose Bengal Test (RBT) and indirect Enzyme-linked Immunosorbent assay (iELISA). Using a Bayesian approach, the correlation-adjusted sensitivity of iELISA was estimated at 96.1 % (Credibility Interval (CrI): 92.7-99.8) whereas that of RBT was 54.9 % (CrI: 23.5-95.1). High correlation-adjusted specificities were found for both tests, 95.0 % (CrI: 91.1-99.6) for iELISA and 97.7 % (CrI: 95.3-99.4) for RBT, respectively. The true prevalence of brucellosis was also estimated using the 1228 tested serum samples to be 4.6 with a 95% credibility interval ranging from 0.6 to 9.5% (Chapter 5 and 6). These results also revealed a good performance for the iELISA, which might consequently be a valuable screening assay under the epidemiological conditions prevailing in Ivory Coast. In Chapter 7, risk factors associated with bovine brucellosis seropositivity were investigated using serological results obtained from 907 serum samples collected from unvaccinated cattle of at least 6 months of age in the savannah-forest region of Ivory Coast. Serum samples were tested using the Rose Bengal test (RBT) and indirect enzyme linked immunosorbent assay (iELISA). The logistic regression analysis indicated that brucellosis seropositivity was associated with age and herd size. Cattle above 5 years of age were found to be more likely seropositive (Odd Ratio (OR) =2.8; 95% Confidence Interval (CI): 1.3, 6.4) compared to cattle under 3 years of age. Similarly, the odds of brucellosis seropositivity for herds with more than 100 cattle was 3.3 (95% CI: 1.2, 8.9) times higher compared to those with less than 50 cattle. The third part presents a general discussion on the overall contribution of the current research (Chapter 8), by highlighting the main results and pointing out their significance. The need for more investigations on the epidemiology of brucellosis, in Ivory Coast and at West African scale, is highlighted. It is neccessary to provide additional knowledge on prevailing field strains of Brucella, on the distribution of the disease and on associated risk factors to implement preventive and control measures. Finally, for more cost-effectiveness and efficiency, the need to strengthen the capabilities of the veterinary services and national laboratories and to consider the control of brucellosis and other zoonotic diseases through a regional, integrated and collaborative perspective is also highlighted. [less ▲]

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See detailContribution to the epidemiology of bovine tuberculosis in northern Ecuador
Proaño Perez, Freddy ULg

Doctoral thesis (2011)

See attached document, page vii

Detailed reference viewed: 49 (3 ULg)
See detailContribution to the evaluation of soil quality around the Naivasha lake (Kenya).
Borgers, nathalie; Colinet, Gilles ULg; Gouder de Beauregard, Anne-Christine et al

Poster (2005, September)

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See detailA contribution to the history of the embryonic development of the Teleosteans
Van Beneden, Édouard ULg

in Quarterly Journal of Microscopical Science (The) (1878), 2(18), 41-57

Detailed reference viewed: 9 (1 ULg)