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See detailEnergy Analysis on Small to Medium Sized H-Bonded Complexes
Dive, Georges ULg; Dehareng, Dominique ULg; Ghuysen, Jean-Marie ULg

in Theoretica Chimica Acta (1993), 85(6), 409-421

Dimers (water-methanol, guanine-cytosine) as well as trimers (methanol-water-imidazole, formamide-methylformate-formamide), are studied as H-bonded complexes of increasing complexity. All the investigated ... [more ▼]

Dimers (water-methanol, guanine-cytosine) as well as trimers (methanol-water-imidazole, formamide-methylformate-formamide), are studied as H-bonded complexes of increasing complexity. All the investigated conformations have been fully optimized. In particular, it is the first time that all the intra- and intermolecular parameters of the guanine-cytosine complex are left variable. In minimal basis sets, the planar conformation has been found to be a first-order critical point. The minimal basis set MINI-1 has been adapted to provide nearly planar amides. The stability of the complexes is accounted for by four energy components of the same order: the first-order term (electrostatic + exchange), the polarization, the charge transfer and the correlation terms. In the case of the studied trimers, the energy components, apart from the electrostatic one, have been found to be nearly additive. [less ▲]

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See detailEnergy and comfort performance analysis of monitored thermally activated building systems combined with geothermal heat pumps
Gantiez, Clément ULg; Lemort, Vincent ULg; Hoogmartens, Jan et al

in International High Performance Buildings Conference at Purdue, July 16-19, 2012 (2012, July)

The combination of geothermal heat pumps (GEO HPs) and thermally activated building systems (TABS), that allow both low temperature heating and high temperature cooling, could yield primary energy savings ... [more ▼]

The combination of geothermal heat pumps (GEO HPs) and thermally activated building systems (TABS), that allow both low temperature heating and high temperature cooling, could yield primary energy savings of around 20- 71% in comparison with conventional heating/cooling systems. However, the potential energy savings are rarely reached in practice due to bad integration of the different subsystems and inefficient control. The present paper presents the analysis of two monitoring campaigns by stressing the influence of relevant parameters such as the performance of components (heat pump, ground heat exchangers, TABS, etc.), building characteristics and the implemented control strategies. The buildings have been monitored and analyzed in the frame of the WKSP-project realized by Institute of Building Services and Energy Design (IGS) at Technical University of Braunschweig. The results show good performance of ground coupled heat pump with seasonal COP up to around 5. Moreover, the use of ground heat exchangers to perform free chilling allows seasonal EER up to 20. Furthermore, the control strategies implemented in the different buildings are quite different. It is also shown that this system can lead to a running cost reduction up to 50% compared to conventional systems and that CO2 emissions can be reduced by 40%. [less ▲]

Detailed reference viewed: 42 (12 ULg)
See detailEnergy and protein levels in dehydrated maize based rations for growing-fattening young bulls
Lambot, O.; Nicks, Baudouin ULg; Denayer, J. et al

in Improvement of quality traits of maize for grain and silage use (1980)

Detailed reference viewed: 13 (4 ULg)
See detailEnergy and protein levels in maize silage rations for growing-fattening young bulls
Denayer, J.; Nicks, Baudouin ULg; Bienfait, Jean-Marie ULg et al

in Improvement of quality traits of maize for grain and silage use (1980)

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See detailEnergy and transmission allocation in overlapping electricity markets : incorporating N-1 security and accounting for losses
Marinakis, Adamantios ULg; Van Cutsem, Thierry ULg

in Proceedings of the 7th international conference on the European Electricity Market (2010, June)

The possibility for market participants to place their bids in markets where they are not geographically located is investigated in this paper. An iterative procedure enabling the simultaneous clearing of ... [more ▼]

The possibility for market participants to place their bids in markets where they are not geographically located is investigated in this paper. An iterative procedure enabling the simultaneous clearing of those overlapping markets by transaction schedulers while managing the resulting pre and post-contingency congestion is proposed. Transmission losses are calculated during the iterations and are accounted for by allocating them to the various transaction schedulers. The procedure is illustrated and commented on a test system. [less ▲]

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See detailEnergy and Transmission Allocation in the presence of Overlapping Electricity Markets
Marinakis, Adamantios ULg; Bakirtzis, Anastasios; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2010), 25(3), 1402-1414

The possibility for market participants to simultaneously place their bids in different markets across an interconnection is investigated in this paper. Transaction schedulers settle multilateral ... [more ▼]

The possibility for market participants to simultaneously place their bids in different markets across an interconnection is investigated in this paper. Transaction schedulers settle multilateral transactions among participants, while a central entity coordinates the overall operation through interactions with the transaction schedulers. Two issues are dealt with in this context. First, the market participants are allowed to place their bids simultaneously in more than one transactions scheduler’s market, and, second, the available transmission capacity is fairly shared among the transaction schedulers. Economically interesting transactions are favored, while confidentiality of market data and independence of transaction schedulers’ clearing mechanisms are preserved. The corresponding iterative algorithm is illustrated in detail on a 15-bus as well as the IEEE-RTS system. [less ▲]

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See detailEnergy audit of air conditioning systems
Andre, Philippe ULg; Hannay, Cl.; Hannay, J. et al

Conference (2007, June)

The work presented here consists in developing an audit methodology, with appropriate simulation tools and benchmarks. Several case studies are used to support, to test and to illustrate these ... [more ▼]

The work presented here consists in developing an audit methodology, with appropriate simulation tools and benchmarks. Several case studies are used to support, to test and to illustrate these developments. Each case study is described according to a standard format, in order to make the data easy to re-use in the future. The audit of the HVAC system consists in analyzing the information available about actual energy performances and in identifying the most attractive retrofit opportunities. Focus is given here to cooling energy consumption, but it could never be completely dissociated from heating requirements. An example of case study is presented in the paper to give a first idea of what could be the (difficult) task of the energy auditor. One of the main difficulties comes from the too many information lacks. Filling these lacks would require, in most case, more detailed energy records on site. Simulation models may help a lot, for a better interpretation of on site records and also for a safe identification of the most promising retrofit opportunities. Such models and examples of simulations are presented in the paper. [less ▲]

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See detailEnergy Balance Closure At Fluxnet Sites
Wilson, K.; Goldstein, A.; Falge, E. et al

in Agricultural and Forest Meteorology (2002), 113(1-4),

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See detailEnergy conservation and CO emissions of fuel oil boilers used in domestic heating
Cuevas, Cristian; Ngendakumana, Philippe ULg

Conference (2006, May)

According to the European standard, the CO emissions of new fuel oil boilers, whose output power is lower than 400 kW, are limited in steady-state regime to 110 mg/kWh of energy consumption. In order to ... [more ▼]

According to the European standard, the CO emissions of new fuel oil boilers, whose output power is lower than 400 kW, are limited in steady-state regime to 110 mg/kWh of energy consumption. In order to assess the performance of actual fuel oil boilers, an experimental work has been performed on a boiler available in the laboratory and whose output nominal power is about 370 kW. The two main parameters investigated are the nozzle capacity and the corresponding fuel injection pressure to keep the same burner consumption. Four nozzles whose capacity ranges from 30 to 45 kg/h at 20 bar were fitted on the burner equipping the fuel oil boiler. All the nozzles used are spill return and 45° type. To assess the CO emissions of the fuel oil boiler, tests have been performed in transient and steady-state regimes. The tests were performed so that the output power was kept constant in steady-state regime (same water flow rate and inlet and outlet temperatures). That is why for each nozzle tested, the fuel injection pressure has been adjusted in order to maintain the fuel mass flow rate at around 37.7 kg/h. On the other hand, the oxygen content of the flue gas in the chimney was kept constant (around 3%) by adjusting only the position of the burner air damper (the position of the flame holder was kept constant) and thus the air combustion mass flow rate. Classical gas analysers were used to measure the CO2, O2, CO and NOx concentrations in the flue gas. The tests performed showed that in steady-state regime, the CO emissions are very low compared to the European standard. On the other hand, in the transient regime (start-up regime for a cycling boiler), the CO emissions are not negligible and increase significantly if a high capacity nozzle is fitted on the fuel oil burner. In short, the paper demonstrates that in order to increase the boiler thermal efficiency and thus to reduce CO2 emissions (for the same output power), one has to avoid the CO emissions in the transient regime. When performing a replacement of the burner nozzle, a low capacity nozzle associated with an adjustment of a high fuel injection pressure is recommended, since a reduction of CO emissions in the starting-up regime is achieved and, on the other hand, the thermal efficiency and the pollutants emissions of the fuel oil boiler in steady state regime are not affected. [less ▲]

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See detailEnergy conservation and dissipation in mitochondria isolated from developing tomato fruit of ethylene-defective mutants failing normal ripening: the effect of ethephon, a chemical precursor of ethylene.
Navet, R.; Jarmuszkiewicz, W.; Almeida, A. et al

in Journal of Bioenergetics & Biomembranes (2003), 35(2), 157-168

Alternative oxidase (AOX) and uncoupling protein (UCP) are present simultaneously in tomato fruit mitochondria. In a previous work, it has been shown that protein expression and activity of these two ... [more ▼]

Alternative oxidase (AOX) and uncoupling protein (UCP) are present simultaneously in tomato fruit mitochondria. In a previous work, it has been shown that protein expression and activity of these two energy-dissipating systems exhibit large variations during tomato fruit development and ripening on the vine. It has been suggested that AOX and UCP could be responsible for the respiration increase at the end of ripening and that the cytochrome pathway could be implicated in the climacteric respiratory burst before the onset of ripening. In this study, the use of tomato mutants that fail normal ripening because of deficiencies in ethylene perception or production as well as the treatment of one selected mutant with a chemical precursor of ethylene have revealed that the bioenergetics of tomato fruit development and ripening is under the control of this plant hormone. Indeed, the evolution pattern of bioenergetic features changes with the type of mutation and with the introduction of ethylene into an ethylene-synthesis-deficient tomato fruit mutant during its induced ripening. [less ▲]

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See detailEnergy conserving balance of explicit time steps to combine implicit and explicit algorithms in structural dynamics
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Computer Methods in Applied Mechanics & Engineering (2006), 195(19-22), 21692192

Recent developments have proved the advantage of combining both time implicit and time explicit integration algorithms in structural dynamics. A major problem is to define the initial conditions for the ... [more ▼]

Recent developments have proved the advantage of combining both time implicit and time explicit integration algorithms in structural dynamics. A major problem is to define the initial conditions for the implicit simulation on the basis of a solution obtained from an unbalanced explicit resolution. The unbalanced nature of the explicit algorithm leads to oscillations in the fields of interest. Therefore, the values obtained after an explicit computation cannot be used directly as initial conditions for an implicit simulation. In this paper, we develop such initial values that lead to a stable (no numerical creation of energy) and energy-conserving transition. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailEnergy consistency in homogenisation-based upscaling scheme for localisation in masonry shells
Mercatoris, Benoît ULg; Massart, T. J.

in International Journal of Fracture (2012), 178(1-2), 259-279

This paper presents an enhanced multi-scale framework for the failure of quasi-brittle thin shells as an improvement of the one proposed in Mercatoris and Massart (Int J Numer Methods Eng 85:1177-1206 ... [more ▼]

This paper presents an enhanced multi-scale framework for the failure of quasi-brittle thin shells as an improvement of the one proposed in Mercatoris and Massart (Int J Numer Methods Eng 85:1177-1206, 2011). The computational homogenisation-based multi-scale methodology is an attractive solution for heterogeneous materials when their characterisation becomes difficult because of complex evolving behaviour such as damage-induced anisotropy and localisation of degradation. An enhanced upscaling scheme for damage localisation in shell structures is proposed using a periodic computational homogenisation procedure and an energy equivalence between mesostructural material instabilities and aggregate macroscopic cracks. The structural cracking is treated by using embedded strong discontinuities incorporated in the shell formulation, the behaviour of which is deduced by an energetically consistent upscaling scheme. The effects of this energy equivalence are discussed based on results of multi-scale simulations of out-of-plane loaded masonry walls including flexural stair-case failure and compared to the results of direct numerical simulations. A good agreement is observed in terms of the load-bearing capacity and of associated energy dissipation. Based on the homogenisation procedure, the orientation of the structural-scale cracking is detected by means of an acoustic tensor-based failure detection adapted to shell kinematics. A multi-scale bifurcation analysis on a simple loading case is performed in order to discuss the selection of the cracking orientation based on energetic considerations. © 2012 Springer Science+Business Media B.V. [less ▲]

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See detailEnergy Consumption : Impacts of Human Activity, Current and Future Challenges, Environmental and Socio-economic Effects
Reiter, Sigrid ULg

Book published by Nova Science Publishers (2013)

Energy is central to sustainable development : it has huge environmental, social, and economic impacts amongst which is its influence on climate change, poverty reduction efforts, industrial and ... [more ▼]

Energy is central to sustainable development : it has huge environmental, social, and economic impacts amongst which is its influence on climate change, poverty reduction efforts, industrial and agricultural productivity and environmental and human health. Developping strategies towards a sustainable energy transition is one of the most important world’s challenges of the twenty-first century. The choices that we will make in the coming years about energy will determine what world future generations will inherit. The book Energy Consumption : Impacts of Human Activity, Current and Future Challenges, Environmental and Socio-economic Effects, gives an overview of the key issues, strategies, operational guidelines and policy implications of current research on transition to more sustainable energy consumption. It investigates the important issue of the relations between human activities, energy systems and energy use. It addresses the environmental, social and economic impacts of energy consumption and their interrelationships. Written by academic and research experts in the field of energy, this book develops strategies for an energy sustainable development of the main energy-intensive sectors: energy production, transportation, buildings, agriculture and domestic appliances. It shows the best opportunities and solutions for energy demand reduction, energy efficiency improvement, increase in the share of renewable energy sources, technological progress and behavioural change in the field of energy. Its aim is to guide the reader to more efficient policies and to actions that really will improve the future. The book addresses also the different issues faced by developing and developed countries as well as their relative respective solutions. It sets out various alternative pathways that are open to our societies. Methods of energy consumption assessment and modeling approaches are also discussed. All those who are interested in the energy challenges will find in this book practical knowledge and operational solutions, providing a solid foundation to help make well-informed choices, as individuals and as societies. [less ▲]

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See detailEnergy Consumption: Preface
Reiter, Sigrid ULg

in Reiter, Sigrid (Ed.) Energy Consumption : Impacts of Human Activity, Current and Future Challenges, Environmental and Socio-economic Effects (2013)

Energy is central to sustainable development : it has huge environmental, social, and economic impacts amongst which is its influence on climate change, poverty reduction efforts, industrial and ... [more ▼]

Energy is central to sustainable development : it has huge environmental, social, and economic impacts amongst which is its influence on climate change, poverty reduction efforts, industrial and agricultural productivity and environmental and human health. Developping strategies towards a sustainable energy transition is one of the most important world’s challenges of the twenty-first century. The choices that we will make in the coming years about energy will determine what world future generations will inherit. The book Energy Consumption : Impacts of Human Activity, Current and Future Challenges, Environmental and Socio-economic Effects, gives an overview of the key issues, strategies, operational guidelines and policy implications of current research on transition to more sustainable energy consumption. It investigates the important issue of the relations between human activities, energy systems and energy use. It addresses the environmental, social and economic impacts of energy consumption and their interrelationships. Written by academic and research experts in the field of energy, this book develops strategies for an energy sustainable development of the main energy-intensive sectors: energy production, transportation, buildings, agriculture and domestic appliances. It shows the best opportunities and solutions for energy demand reduction, energy efficiency improvement, increase in the share of renewable energy sources, technological progress and behavioural change in the field of energy. Its aim is to guide the reader to more efficient policies and to actions that really will improve the future. The book addresses also the different issues faced by developing and developed countries as well as their relative respective solutions. It sets out various alternative pathways that are open to our societies. Methods of energy consumption assessment and modeling approaches are also discussed. All those who are interested in the energy challenges will find in this book practical knowledge and operational solutions, providing a solid foundation to help make well-informed choices, as individuals and as societies. [less ▲]

Detailed reference viewed: 36 (3 ULg)
See detailEnergy dependence of the Jovian ion abundance ratios - Ion accelerarion by Alfven waves
Radioti, Aikaterini ULg; Krupp, N.; Woch, J. et al

Conference (2005)

Detailed reference viewed: 1 (0 ULg)
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See detailEnergy dissipation on a stepped spillway downstream of a Piano Key Weir - Experimental study
Erpicum, Sébastien ULg; Daux, Christophe; Machiels, Olivier ULg et al

in Erpicum, Sébastien; Laugier, Frederic; Boillat, Jean Louis (Eds.) et al Labyrinth and Piano Key Weirs - PKW 2011 (2011)

Piano Key Weir (PKW) is a new type of weir showing appealing hydraulic capacities. Its specific geometric features create different interacting flows and jets downstream of the structure. This suggests ... [more ▼]

Piano Key Weir (PKW) is a new type of weir showing appealing hydraulic capacities. Its specific geometric features create different interacting flows and jets downstream of the structure. This suggests that the use of a PKW to control the flow upstream of a stepped spillway may help in enhancing energy dissipation on the downstream channel. The first results of an experimental study carried out at the Laboratory of Engineering Hydraulics – HACH in the scope of a Coyne & Bellier – Tractebel Engineering project are presented in the paper. The goal of the study was to compare the energy dissipation on a stepped spillway downstream of a PKW with the one which takes place on the same spillway equipped with a standard ogee-crested weir. Despite similar global energy dissipation rates whatever the weir type due to the relative important height of the spillway, significant differences in the aeration of the flow along the spillway have been shown. This paves the way to further investigations. [less ▲]

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See detailEnergy efficiency of sludge drying processes
Léonard, Angélique ULg; Crine, Michel ULg; Arlabosse, Patricia

Conference (2011, November 17)

Detailed reference viewed: 48 (15 ULg)