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See detailHeat transfer characterization in a shallow aquifer using heat and dye tracer tests
Wildemeersch, Samuel ULg; Orban, Philippe ULg; Hermans, Thomas ULg et al

Conference (2013, July 22)

Very low enthalpy geothermal systems (open or closed) are increasingly considered for heating or cooling houses and offices using groundwater energy combined with heat pumps. However, the design and the ... [more ▼]

Very low enthalpy geothermal systems (open or closed) are increasingly considered for heating or cooling houses and offices using groundwater energy combined with heat pumps. However, the design and the impact of current shallow geothermal systems are often set up and assessed in a semi-empirical way. In our country, this situation seems accepted by most of the private partners but not by the authorities and responsible administrations evaluating the impact on groundwater with a mid- to long-term perspective. A rigorous methodology is needed based on a physically based estimation of heat transfer parameters. In this study, the simultaneous use of heat and dye tracers allows estimating simultaneously heat transfer and solute transport parameters in an alluvial aquifer. The experimental field site, located near Liege (Belgium), is equipped with 21 piezometers drilled in the alluvial deposits of the Meuse River. These alluvial deposits are composed of a loam layer (3 m) overlying a sand and gravel layer which constitutes the alluvial aquifer (7 m). The tracing experiment consisted in injecting simultaneously heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in a series of control panels set perpendicularly to the main groundwater flow. Results showed drastic differences between heat transfer and solute transport due to the main influence of thermal capacity of the saturated porous medium. The tracing experiment was then simulated using a numerical model and the best estimation of heat transfer and solute transport parameters is obtained by calibrating this numerical model using inversion tools. The developed concepts and tests may lead to real projects of various extents that can be now optimized by the use of a rigorous and efficient methodology at the field scale. [less ▲]

Detailed reference viewed: 22 (7 ULg)
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See detailHeat transfer characterization using heat and solute tracer tests in a shallow alluvial aquifer
Dassargues, Alain ULg; Wildemeersch, Samuel ULg; Jamin, Pierre ULg et al

Poster (2013, December 09)

Very low enthalpy geothermal systems are increasingly considered for heating or cooling using groundwater energy combined with heat pumps. The design and the impact of shallow geothermal systems are often ... [more ▼]

Very low enthalpy geothermal systems are increasingly considered for heating or cooling using groundwater energy combined with heat pumps. The design and the impact of shallow geothermal systems are often assessed in a semi-empirical way. It is accepted by most of the private partners but not by environmental authorities deploring a lack of rigorous evaluation of the mid- to long-term impact on groundwater. In view of a more rigorous methodology, heat and dye tracers are used for estimating simultaneously heat transfer and solute transport parameters in an alluvial aquifer. The experimental field site, is equipped with 21 piezometers drilled in alluvial deposits composed of a loam layer overlying a sand and gravel layer constituting the alluvial aquifer. The tracing experiment consisted in injecting simultaneously heated water and a dye tracer in a piezometer and monitoring evolution of groundwater temperature and tracer concentration in 3 control panels set perpendicularly to the main groundwater flow. Results showed drastic differences between heat transfer and solute transport due to the main influence of thermal capacity of the saturated porous medium. The tracing experiment was then simulated using a numerical model and the best estimation of heat transfer and solute transport parameters is obtained by calibrating this numerical model using inversion tools. The developed concepts and tests may lead to real projects of various extents that can be now optimized by the use of a rigorous and efficient methodology at the field scale. [less ▲]

Detailed reference viewed: 34 (4 ULg)
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See detailHeat transfer in soils
Hermansson, Ake; Charlier, Robert ULg; Collin, Frédéric ULg et al

in Dawson, Andrew (Ed.) Water in road structures - Movement, Drainage and effects (2009)

Temperature highly affects pavement performance. High and low temperatures not only affects the viscosity of asphalt concrete but also has an impact on the moisture flow within the pavements. At ... [more ▼]

Temperature highly affects pavement performance. High and low temperatures not only affects the viscosity of asphalt concrete but also has an impact on the moisture flow within the pavements. At temperatures below 0°C the freezing of pavements dramatically changes the permeability and frost action might occur forcing water to flow upwards to the freezing front resulting in the frost heave and other pavement distress. [less ▲]

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See detailHeat transfer phenomena in trickle-bed reactors
Crine, Michel ULg

in Chemical Engineering Communications (1982), 19

Detailed reference viewed: 10 (2 ULg)
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See detailHeat transport in dielectric crystals at low temperature: A variational formulation based on extended irreversible thermodynamics
Lebon, Georgy ULg; Dauby, Pierre ULg

in Physical Review (1990), 42

We propose a variational principle applicable to the heat-transport equations derived some years ago by Guyer and Krumhansl [Phys. Rev. 133, 1411 (1964); 148, 766 (1966); 148, 778 (1966)] to describe heat ... [more ▼]

We propose a variational principle applicable to the heat-transport equations derived some years ago by Guyer and Krumhansl [Phys. Rev. 133, 1411 (1964); 148, 766 (1966); 148, 778 (1966)] to describe heat-wave propagation in dielectric crystals at low temperature. The variational principle appears as a generalization of Prigogine's minimum-entropy production criterion. The analysis is based on extended irreversible thermodynamics, which is used to derive the Guyer-Krumhansl equations from macroscopic arguments. [less ▲]

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See detailHeat treatment of pigmented materials from es-Skhul (ca. 100 000 B.P., Israël)
Salomon, Hélène ULg; Vignaud, Colette; Coquinot, Yvan et al

Poster (2010)

Detailed reference viewed: 21 (0 ULg)
Peer Reviewed
See detailHeat-shock treatment modifies gene expression following brain injury
Plumier, Jean-Christophe ULg; David, Jean-claude; Robertson, Harold A. et al

in Supplement ... to the European Journal of Neuroscience (1995), Suppl 8

Detailed reference viewed: 2 (0 ULg)
Peer Reviewed
See detailHeat-stable enterotoxin from a pathogenic canine strain of Escherichia coli
Gerday, C.; Pennetreau-Césa, D.; Gérardin-Otthiers, N. et al

in Biochem (1987), 6

Detailed reference viewed: 8 (5 ULg)
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See detailHeat-triggered drug release systems based on mesoporous silica nanoparticles filled with a maghemite core and phase-change molecules as gatekeepers
Liu, Ji ULg; Detrembleur, Christophe ULg; De Pauw-Gillet, Marie-Claire ULg et al

in Journal of Materials Chemistry B (2014), 2(1), 59-70

Core–shell nanoparticlesmade of a maghemite core and a mesoporous silica shell were developed as drug delivery systems (DDS). Doxorubicin® (DOX, DNA intercalating drug) was loaded within the mesoporous ... [more ▼]

Core–shell nanoparticlesmade of a maghemite core and a mesoporous silica shell were developed as drug delivery systems (DDS). Doxorubicin® (DOX, DNA intercalating drug) was loaded within the mesoporous cavities, while phase-change molecules (PCMs), e.g. 1-tetradecanol (TD) with a melting temperature (Tm) of 39 °C, were introduced as gatekeepers to regulate the release behaviours. An overall loading amount of ca. 20 wt% (TD/DOX ca. 50/50 wt/wt) was confirmed. Heat-triggered release of DOX evidenced a “zero premature release” (<3% of the entire payload in 96 h release) under physiological conditions (37°C), and however, a sustainable release (ca. 40% of the entire payload in 96 h) above Tm of TD (40 °C). It also demonstrated the possibility to deliver drug payloads in small portions (pulsatile release mode) via multiple heating on/off cycles, due to the reversible phase change of the PCMs. In vitro heattriggered release of DOX within cell culture of the MEL-5 melanoma cell line was also tested. It was found that DOX molecules were trapped efficiently within the mesopores even after internalization within the cytoplasm of MEL-5 cells at 37 °C, with the potential toxicity of DOX strongly quenched (>95% viability after 72 h incubation). However, continuous cell apoptosis was detected at cell culture temperature above Tm of TD, due to the heat-triggered release of DOX (<50% viability after 72 h incubation at 40 °C). Moreover, due to the presence of a maghemite core within the DDS, T2-weighted magnetic resonance imaging performance was also confirmed. These as-designed core–shell nanoparticles are envisaged to become promising DDS for “on-demand” heat-triggered release. [less ▲]

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See detailHeating effects on some quality caracteristics of date seed oil.
Besbes, Souhail; Blecker, Christophe ULg; Danthine, Sabine ULg et al

Poster (2004, September)

Detailed reference viewed: 16 (4 ULg)
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See detailHeating effects on some quality characteristics of date seed oil
Besbes, S.; Blecker, Christophe ULg; Deroanne, Claude ULg et al

in Food Chemistry (2005), 91(3), 469-476

Effects of heating on some quality characteristics of date seed oil from two cultivars (Deglet Nour and Allig) has been investigated using an accelerated test in a Rancimat system. Fatty acid, viscosity ... [more ▼]

Effects of heating on some quality characteristics of date seed oil from two cultivars (Deglet Nour and Allig) has been investigated using an accelerated test in a Rancimat system. Fatty acid, viscosity, absorptivity at 232 and 270 nm, colour and total melting enthalpy of Deglet Nour seed oil were less changed compared to that of Allig seed oil, because the former contained a higher amount of total phenolic compounds (526 mug/g against 215 mug/g) and a lower content of unsaturated fatty acids. Viscosity and absorptivity at 232 nm and at 270 nm increased rapidly after reaching the oxidation induction time. Differential scanning calorimetry melting profiles of date seed oils were also changed after heating in the Rancimat. Melting enthalpies seemed to be constant during the initial stages of Rancimat treatment and then reduced after the induction time was reached. The obtained data shows that date seed oils were resistant to thermal treatment during a long period (similar to30-40 h). This may indicate that they could bear thermal treatments that could be applied in refining procedures or in culinary treatments such as frying and cooking conditions. We could also expect that they may have a good shelf life. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailHeating Effects On Some Quality Characteristics Of Date Seed Oil
Besbes, Souhail; Blecker, Christophe ULg; Deroanne, Claude et al

in Food Chemistry (2005), 91(3), 469-476

Effects of heating on some quality characteristics of date seed oil from two cultivars (Deglet Nour and Allig) has been investigated using an accelerated test in a Rancimat system. Fatty acid, viscosity ... [more ▼]

Effects of heating on some quality characteristics of date seed oil from two cultivars (Deglet Nour and Allig) has been investigated using an accelerated test in a Rancimat system. Fatty acid, viscosity, absorptivity at 232 and 270 nm, colour and total melting enthalpy of Deglet Nour seed oil were less changed compared to that of Allig seed oil, because the former contained a higher amount of total phenolic compounds (526 lg/g against 215 lg/g) and a lower content of unsaturated fatty acids. Viscosity and absorptivity at 232 nm and at 270 nm increased rapidly after reaching the oxidation induction time. Differential scanning calorimetry melting profiles of date seed oils were also changed after heating in the Rancimat. Melting enthalpies seemed to be constant during the initial stages of Rancimat treatment and then reduced after the induction time was reached. The obtained data shows that date seed oils were resistant to thermal treatment during a long period ( 30–40 h). This may indicate that they could bear thermal treatments that could be applied in refining procedures or in culinary treatments such as frying and cooking conditions. We could also expect that they may have a good shelf life. [less ▲]

Detailed reference viewed: 66 (9 ULg)
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See detailHeating optimal control applied to a passive solar commercial building
Kummert, M.; Andre, Philippe ULg; Nicolas, Jacques ULg

in Proceedings of EuroSun'98 (1998, September)

Passive solar features can lead to significant energy savings for building heating. However the intrinsic delay between solar gains and heating demand requires an intelligent control of auxiliary HVAC ... [more ▼]

Passive solar features can lead to significant energy savings for building heating. However the intrinsic delay between solar gains and heating demand requires an intelligent control of auxiliary HVAC system to minimise the energy consumption while preventing overheating periods. This paper describes the application of discrete-time optimal control to auxiliary heating of a passive solar commercial building. Simulation-based results using complex reference models are presented and discussed. The optimal controller is compared to classical "heatingcurve + Thermostatic valve" control. It is shown that optimal control can lead to substantial improvement of thermal comfort and energy consumption. [less ▲]

Detailed reference viewed: 15 (1 ULg)
See detailHeavy elements abundances in metal-poor stars
Magain, Pierre ULg; Jehin, Emmanuel ULg; Neuforge, Corinne et al

in American Institute of Physics Conference Series (1998, February 01)

A sample of 21 metal-poor stars have been analysed on the basis of high resolution and high signal-to-noise spectra. Correlations between relative abundances of 16 elements have been studied, with a ... [more ▼]

A sample of 21 metal-poor stars have been analysed on the basis of high resolution and high signal-to-noise spectra. Correlations between relative abundances of 16 elements have been studied, with a special emphasis on the neutron-capture ones. This analysis reveals the existence of two sub-populations of field halo stars, namely Pop IIa and Pop IIb. They differ by the behaviour of the s-process elements versus the alpha and r-process elements. We suggest a scenario of formation of these stars, which closely relates the field halo stars to the evolution of globular clusters. The two sub-populations would have evaporated the clusters during two different stages of their chemical evolution. [less ▲]

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See detailHeavy elements in halo stars: the r/s-process controversy.
Magain, Pierre ULg

in Astronomy and Astrophysics (1995), 297

It has been suggested by Truran (1981) that rapid neutron captures (the r-process) dominate the production of heavy elements in very metal-poor stars. Several spectroscopic works analyzing that hypothesis ... [more ▼]

It has been suggested by Truran (1981) that rapid neutron captures (the r-process) dominate the production of heavy elements in very metal-poor stars. Several spectroscopic works analyzing that hypothesis are reviewed and rediscussed and it is shown that there is, in fact, no secure observational evidence in support of Truran's suggestion. A method to determine the odd-to-even isotopic ratio of barium, and thus to estimate the relative contributions of the r and s-processes, is presented. It takes advantage of the hyperfine structure affecting the spectral lines of the odd isotopes to distinguish them from the even isotopes. This method, applied to the classical metal-poor subgiant HD 140283, shows that the barium isotopic ratio in that star is in agreement with a pure s-process production, and excludes any significant enhancement of the r-process contribution, in disagreement with previous works based on elemental abundances. [less ▲]

Detailed reference viewed: 9 (1 ULg)
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See detailHeavy fermion behavior of U2T2X compounds
Havela, Ladislav; Sechovsky, Vladimir; Svoboda, P. et al

in Journal of Applied Physics (1994), 76(10), 6214-6215

Magnetic and specific-heat studies of U2T2X compounds show a frequent occurrence of the gamma enhancement in conjunction with the onset of antiferromagnetic ordering. The largest value of 830 mJ/mol K**2 ... [more ▼]

Magnetic and specific-heat studies of U2T2X compounds show a frequent occurrence of the gamma enhancement in conjunction with the onset of antiferromagnetic ordering. The largest value of 830 mJ/mol K**2 was observed in U2Pt2In, which is nonmagnetic down to 1.2 K. Variations of electronic structure are documented by optimized relativistic LCAO calculation. [less ▲]

Detailed reference viewed: 11 (1 ULg)
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See detailHeavy fermion behavior of U2T2X compounds
Havela, Ladislav; Sechovsky, Vladimir; Svoboda, P. et al

Poster (1994, August)

Detailed reference viewed: 15 (3 ULg)
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See detailHeavy fermion behavior of U2T2X compounds
Havela, Ladislav; Sechovsky, Vladimir; Svoboda, P. et al

Poster (1994, June)

Detailed reference viewed: 14 (4 ULg)
See detailHeavy meatal dynamics in the Calvi Bay seagrass bed.
Nélissen, Jean-Pierre; Gobert, Sylvie ULg; Bouquegneau, Jean-Marie ULg et al

Conference (1994, January)

Detailed reference viewed: 6 (0 ULg)