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See detailContribution to Entanglement Theory, Applications in Atomic Systems and Cavity QED
Gillet, Jérémie ULg

Doctoral thesis (2011)

We introduce in this thesis two entanglement detection criteria, the Schrödinger-Robertson partial transpose inequality, which can be implemented experimentally in a variety of systems and generalized N ... [more ▼]

We introduce in this thesis two entanglement detection criteria, the Schrödinger-Robertson partial transpose inequality, which can be implemented experimentally in a variety of systems and generalized N-qubit concurrences, which can be used to evaluate multipartite entanglement in N-qubit mixed states. Then, we investigate ways to experimentally produce entanglement by giving a theoretical model which successfully describes the dipole blockade effect. We study its possible applications in systems of two and three two-level atoms as well as its relations with the EITeffect in systems of two three-level atoms. Finally, we show the possibility of two-photon processes in a system of two two-level atoms embedded in a cavity by using perturbation theory and a full master equation approach. We unveil interesting features of blockade and transparency in such cavity QED systems. [less ▲]

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See detailContribution to experimental tests on the seismic behaviour of masonry structural elements
Mordant, Christophe ULg

Master's dissertation (2012)

The objective of this master’s thesis is to contribute to two main aspects of experimental tests on the behaviour of load-bearing masonry subjected to earthquake action carried out within the European ... [more ▼]

The objective of this master’s thesis is to contribute to two main aspects of experimental tests on the behaviour of load-bearing masonry subjected to earthquake action carried out within the European research project SERIES. The first part explains the general context and presents the exploitation of results of the first phase of SERIES project TA5. This first phase investigates the response of four simple unreinforced clay masonry walls, two of them including acoustic insulation devices (SonicStrip). This phase has a double objective. On one hand, the tests aim at a better understanding of the seismic behaviour of single wall in dynamic conditions. On the other hand, the comparison between walls having a same global geometry, but with and without acoustic insulation devices allows the assessment of the consequences of the presence of that type of device on the seismic behaviour. The second part describes the design of specimens and the preliminary assessment of the structural behaviour of the second phase of the SERIES project TA5. The design is focusing on the investigation of the behaviour of T- and L-shaped walls, and in particular on the role of the parts of the structural elements perpendicular to the earthquake direction, and on the characterization of the frame behaviour in such masonry structures. The structural assessment is carried out according to Eurocodes 6 and 8 and considers different loading situations that can be found in daily practice. Some preliminary information on the experimental results of the second phase of the SERIES project TA5 are finally given." [less ▲]

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See detailContribution to fight against counterfeit medecines applying several analytical tools
Marini Djang'Eing'A, Roland ULg; Mbinze Kindenge, Jérémie; Montes, M. L. A. et al

Poster (2010, September)

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See detailContribution to line design by accurate predetermination of severe but occasional stresses.
Lilien, Jean-Louis ULg; Dal Maso, Filipo

in Proceedings of the CIGRE session 1990 (1990, August 27)

Evaluation by simulation of different dynamic loadings are detailed. Including short-circuit, galloping and conductor breakage.

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See detailContribution to pomegranate seeds conservation (Punica granatum L.) by osmotic dehydration
Bchir, Brahim ULg

Doctoral thesis (2011)

The aim of this work was to create a complete conservation process of pomegranate seeds (Punica granatum L.). This process is essentially based on osmotic dehydration (OD), which was associated to ... [more ▼]

The aim of this work was to create a complete conservation process of pomegranate seeds (Punica granatum L.). This process is essentially based on osmotic dehydration (OD), which was associated to freezing and air-drying process. Several parameters were studied to optimize the process such as osmotic solution (sucrose, glucose, and sucrose/glucose and date juice with sucrose added), temperature (30, 40, and 50°C) and state of the fruit (fresh and frozen). All these conditions were linked to seed proprieties (texture, structure, and colour). The study of osmotic dehydration parameters (water loss (WL), solids gain (SG) and weight reduction (WR)) showed that most significant changes of mass transfer took place during the first 20 min of dewatering using frozen seeds, independently of temperature and sugar type. During this period, seeds water loss was estimated at 46% in sucrose, 41% in sucrose/glucose mix, 39% in date juice, and 37% in glucose. Mass transfer was slower starting from fresh fruit but led to a higher rate of WL at the end of the process. This fact can be explained by scanning electron microscopy, which showed damage of seed cell structure after freezing. This has practical consequences in terms of the modification of seeds texture. The same process also revealed a modification of seed texture and cell structure after osmotic dehydration. Using a sucrose solution and a temperature of 50°C favoured the best mass transfer. The determination of different water fractions of seed by differential scanning calorimetry (DSC) showed that the % of frozen water decreased 3.5 times contrary the % of unfreezable water that increased 2.5 times. This favours a better seeds conservation. During osmotic dehydration, there was a non negligible leaching of natural solutes from seeds into the solution, which might have an important impact on the sensorial and nutritional value of seeds. Using only osmotic dehydration could not maintain the stability of seeds during conservation. In fact, after the osmotic process, water activity of seeds was found to be higher than 0.9, allowing to the development of microorganisms and some undesirable reactions. As a consequence, a drying of the pomegranate seeds (during four hours) was investigated at three different temperatures (40, 50, and 60 °C) with air flow rate of 2 ms-1. Prior to the drying process, seeds were osmodehydrated in a sucrose solution (55°Brix) during 20 min at 50°C. The drying kinetics and the effects of OD and air-drying temperature on antioxidant capacity, total phenolic, colour, and texture were determined. This work is a contribution to the study of physico-chemical properties of pomegranate seeds (Punica granatum L.) during freezing, osmotic dehydration and drying. After the global process, the pomegranate seed characteristics lead to new industrial developments. [less ▲]

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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

Detailed reference viewed: 21 (8 ULg)