Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailA heat and dye tracer test for characterizing and modelling heat transfer in an alluvial aquifer
Klepikova, Maria ULg; Wildemeersch, Samuel; Jamin, Pierre ULg et al

Poster (2014, September 22)

Using heat as an active tracer is a topic of increasing interest with regards to characterizing shallow aquifers for ATES (Aquifer Thermal Energy Storage) systems. In this study, we investigate the ... [more ▼]

Using heat as an active tracer is a topic of increasing interest with regards to characterizing shallow aquifers for ATES (Aquifer Thermal Energy Storage) systems. In this study, we investigate the potential interest of coupling simultaneous heat and dye tracer injection tests for characterization of an alluvial aquifer. The study site is located near Liege in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in nine monitoring wells located according to three transects with regards to the main groundwater flow direction. The breakthrough curves measured in the recovery well showed that heat transfer in the alluvial aquifer is slower and more dispersive than solute transport. Recovery is very low for heat while in the same time it is measured as relatively high for the solute tracer. This shows how heat diffusion is larger than molecular diffusion, implying that exchange between groundwater and the porous medium matrix is far more significant for heat than for solute tracers. In a first step, temperature and concentrations in the recovery well are used for estimating the specific heat capacity with an energy balance calculation and the estimated value is found to be consistent with those found in the literature. Then, the measured temperature breakthrough curves in the piezometers are used for constraining the heat transport model. They are highly contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. A preliminary interpretation of these temperature breakthrough curves is provided with first results from the model. Then it will allow for estimating the entire set of heat transfer parameters and their spatial distribution by inverse modelling. 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: 29 (5 ULg)
Peer Reviewed
See detailHeat and mass balances on an anaerobic digester treating agricultural wastes
Piemme, Olivier; Lebon, F.; Crine, Michel ULg

in Biomass for Energy, Environment, Agriculture and Industrie (1995)

Detailed reference viewed: 38 (3 ULg)
Full Text
See detailHeat and mass transfer coefficient analysis during rock convective drying
Prime, Noémie ULg; Housni, Zakarya; Fraikin, Laurent ULg et al

Conference (2013, August)

This paper presents some experimental investigations about convective drying of rocks. Cylindrical samples made of limestone are dried from one their bases submitted to an air flow, while the other ... [more ▼]

This paper presents some experimental investigations about convective drying of rocks. Cylindrical samples made of limestone are dried from one their bases submitted to an air flow, while the other surfaces are hermetically covered. All other factors being equal, the influence of two parameters is looked after: the cylinder height, equivalent to the volume/surface ratio of the samples, and the direction of the air flow. The tests are interpreted both from the drying curves and from the values of water and heat transfer coefficients. Results first highlight that air flow incidence on the dried surface changes the kinetics and the transfer coefficient values. It can thus be supposed that the air flow direction would modify the thickness of the transfer limit layer at the surface and/or would make invalid the hypothesis of such a limit layer model for some flow configurations. Besides, the volume/surface ratio is shown to be correlated to the evaporation flux on the constant drying phase, and thus to the transfer coefficients. Nonetheless, this link tends to disappear from sufficiently high values of the volume/surface ratio since, in this case, the transfer coefficients reach constant values. This effect, in addition to other observations made on the drying curves, well fits with the hypothesis of a hydraulically connected layer below the drying surface, which would maintain during the constant drying rate phase. In the present case, this layer would have a thickness of around 20 to 30 mm. [less ▲]

Detailed reference viewed: 89 (17 ULg)
Full Text
Peer Reviewed
See detailHeat can erase epigenetic marks of vernalization in Arabidopsis
Bouché, Frédéric ULg; Detry, Nathalie ULg; Périlleux, Claire ULg

in Plant Signaling & Behavior (2015), 10(3), 990799

Vernalization establishes a memory of winter that must be maintained for weeks or months in order to promote flowering the following spring. The stability of the vernalized state varies among plant ... [more ▼]

Vernalization establishes a memory of winter that must be maintained for weeks or months in order to promote flowering the following spring. The stability of the vernalized state varies among plant species and depends on the duration of cold exposure. In Arabidopsis thaliana, winter leads to epigenetic silencing of the floral repressor gene FLOWERING LOCUS C (FLC) and the duration of cold is measured through the dynamics of chromatin modifications during and after cold. The growing conditions encountered post-vernalization are thus critical for the maintenance of the vernalized state. We reported that high temperature leads to devernalization and, consistently, to FLC reactivation in Arabidopsis seedlings. Here we show that the repressive epigenetic mark H3K27me3 decreases at the FLC locus when vernalized seedlings are grown at 30°C, unless they were first exposed to a stabilizing period at 20°C. Ambient temperature thus controls the epigenetic memory of winter. [less ▲]

Detailed reference viewed: 100 (22 ULg)
Full Text
Peer Reviewed
See detailHeat conduction at micro and nanoscales: A review through the prism of Extended Irreversible Thermodynamics
Lebon, Georgy ULg

in Journal of Non-Equilibrium Thermodynamics (2014), 39(1), 35-59

Detailed reference viewed: 8 (0 ULg)
See detailHeat generation and transfer due to friction and plastic dissipation - a coupled thermomechanical approach
Adam, L.; Ponthot, Jean-Philippe ULg

in Proceedings of HEFAT 2003, 2nd International conference on Heat Transfer, Fluid Mechanics and Thermodynamics (2003)

Detailed reference viewed: 40 (1 ULg)
See detailHeat generation due to friction and plastic dissipation – a coupled thermomechanical approach for impact and metal forming simulation
Adam, L.; Ponthot, Jean-Philippe ULg

in Proceedings of Int. Conf. on Computational Methods for Coupled Problems in Science and Engineering – COUPLED PROBLEMS 2005 (2005)

Detailed reference viewed: 71 (1 ULg)
Full Text
Peer Reviewed
See detailA heat injection and pumping experiment in a gravel aquifer monitored with crosshole electrical resistivity tomography
Hermans, Thomas ULg; Wildemeersch, Samuel ULg; Jamin, Pierre ULg et al

in EarthDoc - Near Surface Geosciences 2013 - 19th European Meeting of Environmental and Engineering Geophysics (2013, September)

Thermal tracing experiments are becoming common in hydrogeology to estimate parameters governing heat transport processes and to study geothermal reservoirs. Electrical resistivity tomography (ERT) has ... [more ▼]

Thermal tracing experiments are becoming common in hydrogeology to estimate parameters governing heat transport processes and to study geothermal reservoirs. Electrical resistivity tomography (ERT) has proven its ability to monitor salt tracer tests, but few studies have investigated its performances in thermal tracing experiments. In this study, we monitor the injection and pumping of heated water using crosshole ERT in a panel crossing the main flow direction. Difference inversion time-lapse images clearly show the heterogeneous pattern of resistivity changes, and thus temperature changes, highlighting the existence of preferential flow paths in the aquifer. Comparison of temperature estimates from ERT and direct measurements in boreholes show the ability of ERT to quantify the temperatures in the aquifer and to draw the breakthrough curves of the thermal tracer with a relative accuracy. Such resistivity data may provide important information to improve hydrogeological models. Our study proves that ERT, especially crosshole ERT, is a reliable tool to follow thermal tracing experiments. It also confirms that ERT should be included to in situ techniques to characterize heat transfer in the subsurface and to monitor geothermal resources exploitation. [less ▲]

Detailed reference viewed: 48 (22 ULg)
Full Text
Peer Reviewed
See detailA heat piloted residential 5 kW fuel cell
Lilien, Jean-Louis ULg; Maréchal, François; Lerson, Sébastien et al

(2004, August)

based on residential house demand (electrical, heating, domestic hot water), the optimisation of the use of a SOFC fuel cell of about 5 kWe is detailed to reduce CO2 emission at their minimum.

Detailed reference viewed: 47 (2 ULg)
Full Text
Peer Reviewed
See detailHeat Pumping and Reversible Air Conditioning - First Case Study Results
Aparecida Silva, Cleide; Bertagnolio, Stéphane ULg; Hannay, Jules et al

Conference (2007, April)

Detailed reference viewed: 72 (4 ULg)
Full Text
Peer Reviewed
See detailHeat pumping and reversible air conditioning : how to make the best use of HVAC equipment ?
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg et al

Conference (2008)

Substituting a heat pump to a boiler may save more than 50% of primary energy, if electricity is produced by a modern combined cycle power plant (and even more if a part of that electricity is produced ... [more ▼]

Substituting a heat pump to a boiler may save more than 50% of primary energy, if electricity is produced by a modern combined cycle power plant (and even more if a part of that electricity is produced using renewable sources). Two of the most attractive heat pumps applications consist in recovering the heat rejected by the condenser of an existing chiller and in using this chiller in reversible mode. This is the topic of the IEA-ECBCS Annex 48 project (“Heat pumping and reversible air conditioning”). An overview of the project is presented and the work of the different participants is briefly explained. Case studies are also briefly presented and more details are given on one of them. [less ▲]

Detailed reference viewed: 58 (3 ULg)
Full Text
Peer Reviewed
See detailHeat Pumping and Reversible Air Conditioning: How to make the best use of HVAC equipment ?
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg et al

in Proceedings of the 9th International IEA Heat Pump Conference, Zurich, Switzerland (2008, May)

Detailed reference viewed: 72 (13 ULg)
Full Text
Peer Reviewed
See detailHeat Pumping and Reversible Air Conditioning: Retrofit opportunities in a laboratory building
Aparecida Silva, Cleide; Bertagnolio, Stéphane ULg; Hannay, Jules et al

Conference (2007, September)

Detailed reference viewed: 117 (10 ULg)
Full Text
Peer Reviewed
See detailHeat pumping and reversible air-conditioning : a new project of the international energy agency.
Afjei, Th.; Andre, Philippe ULg; Halozan, H. et al

in Bertoldi, Paolo; Atanasiu, Bogdan (Eds.) Proceeding of the international conference IEECB'06 (2006)

Detailed reference viewed: 23 (3 ULg)
Full Text
See detailHeat recovery and reversible heat pumping potentials in non-residential buildings
Bertagnolio, Stéphane ULg; Lebrun, Jean; Andre, Philippe ULg et al

Conference (2008, September)

Detailed reference viewed: 30 (6 ULg)
Full Text
Peer Reviewed
See detailHEAT RECOVERY SYSTEMS FOR PASSENGERS VEHICLES
Glavatskaya, Yulia ULg; Olivier, Gérard; Shonda, Osoko et al

in Scientific Bulletin, Automotive series = Buletin Ştiinţific, Seria Autovehicule Rutiere (2011, November 02)

is wasted through the cooling liquid and the exhaust gases. Thus, it would be possible to convert this wasted heat in order to improve the engine overall efficiency and reduce the fuel consumption of the ... [more ▼]

is wasted through the cooling liquid and the exhaust gases. Thus, it would be possible to convert this wasted heat in order to improve the engine overall efficiency and reduce the fuel consumption of the vehicle. This shows the big interest in energy recovery systems. This paper presents the various systems enabling the recovery of this energy. A Rankine cycle, widely used in the industry, is of particular interest. The efficiency of energy conversion varies from 5 to 20 % depending of its conception (working fluid, architecture, coupling…). Moreover, the layout of the Rankine cycle integrated within a vehicle depends on the choice of the working fluid as well as the technologies of the components i.e. the expander, the evaporator, the condenser and the pump. Within this context, the issue regarding the mass and the size of the system has to be considered. Finally, we present several solutions of Rankine systems for passenger car application and show each advantage and limits. [less ▲]

Detailed reference viewed: 75 (4 ULg)
Peer Reviewed
See detailHeat shock increases the activity of endothelial nitric oxide synthase via HSP90-independent mechanisms
Plumier, Jean-Christophe ULg; Salomone, Salvatore; Qiu, Janhua et al

Poster (2002)

Detailed reference viewed: 1 (0 ULg)
Peer Reviewed
See detailHeat Shock Proteins ans antioxidative enzymes in myocardial protection
Currie, R.W.; Plumier, Jean-Christophe ULg

in Knowlton, A.A. (Ed.) Heat Shock Proteins and the Cardiovascular System (1996)

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailHeat shock proteins. I : Classification and roles in pathological processes
Wirth, Delphine; Gustin, Pascal ULg; Drion, Pierre ULg et al

in Annales de Médecine Vétérinaire (2002), 146(4), 201-216

All living systems have evolved mechanisms to maintain homeostasis in the face of rapid environmental changes. When exposed to elevated temperatures, most of the cells activate the synthesis of a specific ... [more ▼]

All living systems have evolved mechanisms to maintain homeostasis in the face of rapid environmental changes. When exposed to elevated temperatures, most of the cells activate the synthesis of a specific group of proteins called Heat Shock Proteins (Hsps). This heat shock response, under control of specific transcription factors, the Heat Shock factors (HSF), is an evolutionarily conserved mechanism, from bacteria to humans. Heat Shock Proteins are classified into families according to their molecular weight (Hsp 25, 40, 70, 90, 105). They play the role of molecular chaperones by binding and protecting other molecules (proteins, RNAs). The function of Hsp is to prevent accumulation of non-native proteins either by assisting proper folding of polypeptides or by driving them to proteosome pathway for degradation. Hsps are involved in various pathological processes that are accompanied by protein alterations such as chronic or degenerative diseases. This review describes structural and functional characteristics of the six main Hsps classes. It also focuses on their respective role in highly studied pathologies. The diversity of Hsps implications in these diseases explains that they became recently a strategic target in development of new therapeutic strategies. [less ▲]

Detailed reference viewed: 109 (5 ULg)
Peer Reviewed
See detailThe Heat Shock Response and Tissue Protection
Currie, R.W.; Plumier, Jean-Christophe ULg

in Baxter, B.F.; Yellon, D.M. (Eds.) Delayed Preconditioning and Adaptative Cardioprotection (1998)

Detailed reference viewed: 14 (1 ULg)