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See detailL'élément d'extranéité au sein des faits générateurs de la demande et la règle de conflit comme règle de droit
Boularbah, Hakim ULg

in J. Linsmeau et M. Storme : Le rôle respectif du juge et des parties dans le procès civil (1999)

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See detailElément de coque à géométrie de révolution
Debongnie, Jean-François ULg

Report (1974)

The first par of this report is focused on the formulation of the conical shell element in SAMCEF. In chapter 2, benchmark applications of this element in statics are discussed. Chapter 3 is devoted to ... [more ▼]

The first par of this report is focused on the formulation of the conical shell element in SAMCEF. In chapter 2, benchmark applications of this element in statics are discussed. Chapter 3 is devoted to numerical tests in modal analysis. [less ▲]

Detailed reference viewed: 51 (2 ULg)
See detailElement Diffusion in the Solar Interior
Thoul, Anne ULg; Bahcall, J.N.; Loeb, A.

Poster (1992, December)

We study the diffusion of helium and other heavy elements in the solar interior, using the flow equations developed by Burgers (1969) for a multi-component fluid. The set of equations is solved exactly ... [more ▼]

We study the diffusion of helium and other heavy elements in the solar interior, using the flow equations developed by Burgers (1969) for a multi-component fluid. The set of equations is solved exactly, including the residual heat flow terms. No approximation is made about the relative concentrations and no restriction is placed on the number of elements considered. For helium diffusion, we compare our results with those obtained by Bahcall and Loeb (1990) using a simplified treatment with heat flows neglected. We find that the inclusion of the residual heat flow terms leads to a significant increase in the helium diffusion velocity. However, we also find that the temperature and charge-dependence of the Coulomb logarithm has the opposite effect, leading to a decrease in the helium diffusion velocity. By coincidence, the two effects partially cancel each other out throughout most of the solar interior. Our complete treatment of element diffusion could be directly incorporated in a standard stellar evolution code, but, for convenience, we also give simple analytical fits of our numerical results. Burgers, J.M. 1969, Flow equations for composite gases(Academic Press, New York). Bahcall, J.N., and Loeb, A. 1990, Ap.J.,360, 267. [less ▲]

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See detailELEMENT DIFFUSION IN THE SOLAR INTERIOR
Thoul, Anne ULg; BAHCALL, J. N.; LOEB, A.

in Astrophysical Journal (1994), 421(2), 828-842

We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multicomponent fluid, including the residual heat ... [more ▼]

We study the diffusion of helium and other heavy elements in the solar interior by solving exactly the set of flow equations developed by Burgers for a multicomponent fluid, including the residual heat-flow terms. No approximation is made concerning the relative concentrations, and no restriction is placed on the number of elements considered. We give improved diffusion velocities for hydrogen, helium, oxygen, and iron, in the analytic form derived previously by Bahcall & Loeb. These expressions for the diffusion velocities are simple to program in stellar evolution codes and are expected to be accurate to similar to 15%. We find that the inclusion of the residual heat flow terms leads to an increase in the hydrogen diffusion velocity. We compare our numerical results-with those obtained analytically by Bahcall & Loeb using a simplified treatment, as well as with those derived numerically by Michaud & Proffitt. We find that for conditions characteristic of the Sun, the results of Bahcall & Loeb for the hydrogen diffusion velocity are smaller than our more accurate numerical results by similar to 30%, except very near the center where the error becomes larger. The Michaud & Proffitt results differ from the numerical results derived here by less than or similar to 15%. Our complete treatment of element diffusion can be directly incorporated in a standard stellar evolution code by means of an exportable subroutine, but, for convenience, we also give simple analytical fits to our numerical results. [less ▲]

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See detailUn élément Epontilles pour LBR5-Report R&D5
Rigo, Philippe ULg

Report (2003)

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See detailElement fluxes, forest floor characteristics and microbial activities under deciduous tree species after conversion of a Norway spruce (Picea abies (L.) Karst.) stand
Bazgir, Masoud ULg; Guillaume, Patricia ULg; Carnol, Monique ULg

Poster (2011, March)

Forest management is currently confronted with major questions, such as how to adapt plantation forests to a changing world. This questioning is not only essential with regard to forest health and ... [more ▼]

Forest management is currently confronted with major questions, such as how to adapt plantation forests to a changing world. This questioning is not only essential with regard to forest health and productivity, but also within the frame of climate mitigation. As Norway spruce monocultures (Picea abies) have been planted in Europe beyond their assumed natural range, are subjected to forest decline and have negative impacts on ecological conditions, conversion into mixed stands has been suggested. Tree species can influence nutrient inputs, soil microbial activity, soil chemistry and nutrient cycling in forest ecosystems. These tree species effects on biogeochemical cycles may vary according to soil type, site characteristics and land use history. The objective of the present study was to quantify element fluxes in throughfall and seepage water, forest floor exchangeable element pools and nitrogen transformations, 12 years after conversion from Picea abies monocultures to a mixed forest stand. Measurements were performed under young and mature Picea abies, Alnus glutinosa (L.) Gaertn., Quercus robur L. and Sorbus aucuparia L. Thus trees have grown on the same site, sharing identical initial soil conditions and site history, so that potential effects on microbial processes and soil properties can be imputed to tree species. Results showed that conversion had a short term impact on nutrient budgets and nutrient cycling in the upper soil layer; in particular on input fluxes of acidifying cations, soil base saturation, net N mineralization and nitrification. [less ▲]

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See detailElement removal in harvested tree biomass: scenarios for critical loads in Wallonia, south Belgium
Bosman, Bernard ULg; Remacle, Jean; Carnol, Monique ULg

in Water, Air & Soil Pollution : Focus (2001), 1

The critical load concept is now widely used as a tool for developing emission control policies in Europe. As a signatory country of the Convention of Long-Range Transboundary Air Pollution, critical ... [more ▼]

The critical load concept is now widely used as a tool for developing emission control policies in Europe. As a signatory country of the Convention of Long-Range Transboundary Air Pollution, critical loads for acidity, nutrient nitrogen, nitrogen and sulphur have been calculated for the Flemish and Walloon regions in Belgium. This paper describes the methodology used for estimating critical loads for forest soils in the Walloon region according to the Steady-State Mass Balance equations. As an example the methodology was applied to the catchment `Waroneu', situated in a sensitive area of the Haute Ardenne. Main input parameters to the equations were derived from precipitation and runoff data of the catchment study. Improved estimates of nitrogen uptake (Nu) and base cation uptake (BCu) were obtained by intensive sampling of Picea abies and Quercus robur trees. Nutrient contents (Ca, Mg, K, N) and nutrient to nitrogen ratios of Picea abies reflected the poor soil quality at a site with high N deposition. Quercus robur nutrient contents increased from stem to higher order branches with a high proportion of nutrients located in the bark. However the simulation of stem only harvesting had a minor effect on critical loads. Measured wood densities were lower than reported literature values with a main effect on Nu and BCu estimates. The use of recommended default values and/or data derived from the experimental site resulted in a wide range of critical loads, some of which were largely overestimated. Results demonstrated the importance of site specific data for critical load calculations. [less ▲]

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See detailElement-Free Galerkin Method for Crack Propagation
Ponthot, Jean-Philippe ULg; BELYTSCHKO, T.

Conference (1999)

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See detailElemental 2D imaging of paintings with a mobile EDXRF system
Hocquet, François-Philippe ULg; Calvo Del Castillo, Helena ULg; Cervera Xicotencatl, Ariadna ULg et al

in Analytical and Bioanalytical Chemistry (2011), 399(9), 3109-3116

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied ... [more ▼]

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied. X-ray radiography and infrared reflectography as well as UV photography are some of the most applied techniques. The study of works of art usually requires these techniques to be non-invasive. Furthermore, they are frequently required to perform in situ analysis. A few years ago, our laboratory developed a mobile energy-dispersive X-ray fluorescence and UV-vis-NIR coupled spectrometer, especially designed for fieldwork studies, where all three techniques can be applied strictly at the same site of analysis. Recent developments on a new positioning system have now allowed us to perform 2D elemental mappings with our equipment, which is especially well adapted to painting analysis. The system control is carried out entirely through a laptop computer running a dedicated homemade software. The positioning is achieved by means of a CCD camera embedded in the system and controlled via a Wi-Fi connection through the computer. The data acquisition system, which is made through a homemade multichannel pulse height analyzer, being also managed via the software mentioned above, goes through an Ethernet connection. We will present here the new developments of the system and an example of in situ 2D elemental mapping applied on an anonymous oil painting on wood panel. The discovery of a hidden painting under this oil painting makes it a good choice for a first example of 2D large scan with a mobile instrument. © Springer-Verlag 2010. [less ▲]

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See detailElemental and Isotopic Abundances in Metal-Poor Stars
Magain, Pierre ULg

in Walsh, J. R.; Danziger, I. J. (Eds.) Science with the VLT, Proceedings of the ESO Workshop held at Garching, Germany, 28 June - 1 July 1994 (1995)

Not Available

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See detailThe elementary reactions of energy selected 1,1-Difluoroethene ions.
Güthe, F.; Weitzel, K.-M.; Baumgärtel, H. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1996)

The dissociative photoionization dynamics of 1,1-difluoroethene has been investigated by TPEPICO using synchrotron radiation. The breakdown diagram has been build. The attention has been focussed on C2HF ... [more ▼]

The dissociative photoionization dynamics of 1,1-difluoroethene has been investigated by TPEPICO using synchrotron radiation. The breakdown diagram has been build. The attention has been focussed on C2HF+ (HF-loss) channel. [less ▲]

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See detailAn elementary shortest path problem with variable service start time
Kucukaydin, Hande ULg; Arda, Yasemin ULg; Crama, Yves ULg

Conference (2013, May 02)

We consider an elementary shortest path problem with resource constraints (ESPPRC), where a capacitated single vehicle serves a set of delivery and backhaul customers with a revenue and a time window. On ... [more ▼]

We consider an elementary shortest path problem with resource constraints (ESPPRC), where a capacitated single vehicle serves a set of delivery and backhaul customers with a revenue and a time window. On a given route, the vehicle can visit a backhaul customer only after all its delivery customers are visited, where a customer is either a delivery or a backhaul customer, but not both. Split deliveries and pick-ups are not allowed. In this problem, multiple trips are allowed so that the vehicle can be assigned to several routes. In addition, the vehicle can begin servicing the customers at any desired time and can be used for at most a fixed amount of time that depends on the shift duration of the assigned driver. Distance and time based variable costs are incurred by serving the customers. In other words, the total cost depends on the total distance traveled and the total amount of time that the vehicle spends by performing the assigned multiple trips. On the other hand, serving a customer yields also a revenue. Therefore, the aim is to determine the optimal service start time of the vehicle from the depot along with the trips to be performed in order to minimize the routing costs minus the collected revenues. Such a problem can be faced as the pricing subproblem in branch-and-price algorithms for vehicle routing problems with additional constraints, where the revenues are equivalent to the dual prizes of the visited vertices. In general, ESPPRC can be solved to optimality by using a dynamic programming algorithm. However, since the vehicle can start the service at any point in time and is paid based on the total time during which it has been used, our ESPPRC has to take an infinite number of Pareto-optimal states into account. Therefore, we adapt the well-known dynamic programming algorithm according to this feature and develop piecewise linear time functions that represent total traveling and waiting time depending on a variable start time at the depot. Consequently, we propose appropriate dominance rules to discard feasible paths that cannot lead to the optimal solution. Finally, we present computational results. [less ▲]

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See detailElementi di docimologia : valutazione continua e esami
de Landsheere, Gilbert ULg

Book published by La Nuova Italia Editrice (1973)

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See detailElementi di docimologia : valutazione continua ed esami
de Landsheere, Gilbert ULg

Book published by La Nuova Italia (1974)

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See detailÉlements affectant la précision du GPS RTK
Wautelet, Gilles ULg

Conference given outside the academic context (2013)

Detailed reference viewed: 57 (4 ULg)
See detailEléments d’actualité fiscale
Bourgeois, Marc ULg

Conference given outside the academic context (2013)

Detailed reference viewed: 3 (0 ULg)