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
Peer Reviewed
See detailDevelopment of a combined mechanical and enzymatic method for the isolation of intact preantral follicles from fetal, calf and adult bovine ovaries
Figueiredo, José Ricardo; Hulshof, S. C. J.; Van den Hurk, R. et al

in Theriogenology (1993), 40(4), 789-799

The isolation of preantral follicles from the ovaries of bovine fetuses, calves and adult cows was performed using a simple, rapid mechanical and enzyme method. The ovaries were cut into small pieces with ... [more ▼]

The isolation of preantral follicles from the ovaries of bovine fetuses, calves and adult cows was performed using a simple, rapid mechanical and enzyme method. The ovaries were cut into small pieces with a tissue chopper. Then, the suspension was filtered successively through 500 and 100 μm nylon mesh filters. This simple mechanical procedure resulted in large numbers of isolated preantral follicles: 2,142 ± 254; 512 ± 92 and 298 ± 54 from the ovaries of bovine fetuses, calves and cows, respectively. In addition, the ovarian fragments between 100 and 500 μm were suspended in 10 ml of M199 Hepes medium plus 5% FCS and divided into 2 equal parts: one portion was used for collagenase treatment (200 U/ml) for 20 minutes, while the other served as a control. Collagenase treatment resulted in 841 ± 161; 216 ± 51 and 52 ± 17 preantral follicles from fetuses, calves and cows, respectively, compared with 312 ± 86; 52 ± 15 and 10 ± 2 in the control group. The use of collagenase with ovarian fragments selected by filtration as a method for increasing the rate of recovery of preantral follicles is described here. [less ▲]

Detailed reference viewed: 76 (11 ULiège)
Full Text
Peer Reviewed
See detailDevelopment of a compact single room ventilation unit with heat recovery dedicated to tertiary buildings
Gendebien, Samuel ULiege; Martens, Jonathan; Prieels, Luc et al

Conference (2015)

In the frame of the European project called Bricker, a new prototype of single room ventilation with heat recovery has been developed. This new unit is supposed to be installed in class rooms of an ... [more ▼]

In the frame of the European project called Bricker, a new prototype of single room ventilation with heat recovery has been developed. This new unit is supposed to be installed in class rooms of an educational institution. This paper deals with the development of the first prototype of this unit. An empirical model of such device is also proposed in order to be coupled with a building model. This aims at determining the seasonal performance of the device and thus the potential energy saving (compared to other technologies) resulting from its use. The first part of the paper presents the specifications and the final characteristics of the developed device. In this context, a by-pass for free cooling in summer conditions as well as the strategies under frosting conditions are described. Secondly, the coefficient of performance (COP) of such device is recalled. In the early stage of the development process, the COP is determined based on the manufacturer data of the heat recovery exchanger and the fans. The coupling between fan curve and the predicted hydraulic performance of the unit allows for determining a first approximation of the fans electrical consumption for several delivered flow rates. The third part of the paper focuses on the experimental investigations carried out in order to determine the flow rate really delivered by the unit. Electrical consumptions of several flow rates are also measured in order to characterize the COP of the unit in those conditions. Finally, a comparison between the measured and the predicted performance based on manufacturer data has been realized in terms of COP. A performance map based on experimental results is proposed in order to be coupled with a building model. [less ▲]

Detailed reference viewed: 83 (29 ULiège)
Full Text
Peer Reviewed
See detailDevelopment of a compartment model based on CFD simulations for mixing description in bioreactors
Delafosse, Angélique ULiege; Delvigne, Frank ULiege; Collignon, Marie-Laure ULiege et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(2), 517-522

Understanding and modelling the complex interactions between biological reaction and hydrodynamics is a key problem when dealing with bioprocesses. It is fundamental to be able to accurately predict the ... [more ▼]

Understanding and modelling the complex interactions between biological reaction and hydrodynamics is a key problem when dealing with bioprocesses. It is fundamental to be able to accurately predict the hydrodynamics behaviour of bioreactors of different size and its interaction with the biological reaction. CFD can provide detailed modelling about hydrodynamics and mixing. However, it is computationally intensive, especially when reactions are taken into account. Another way to predict hydrodynamics is the use of "Compartment" or "Multi-zone" model which are much less demanding in computation time than CFD. However, compartments and fluxes between them are often defined by considering global quantities not representative of the flow. To overcome the limitations of these two methods, a solution is to combine compartment modelling and CFD simulations. Therefore, the aim of this study is to develop a methodology in order to propose a compartment model based on CFD simulations of a bioreactor. The flow rate between two compartments can be easily computed from the velocity fields obtained by CFD. The difficulty lies in the definition of the zones in such a way they can be considered as perfectly mixed. The creation of the model compartments from CFD cells can be achieved manually or automatically. The manual zoning consists in aggregating CFD cells according to the user's wish. The automatic zoning defines compartments as regions within which the value of one or several properties are uniform with respect to a given tolerance. Both manual and automatic zoning methods have been developed and compared by simulating the mixing of an inert scalar. For the automatic zoning, several algorithms and different flow properties have been tested as criteria for the compartment creation. [less ▲]

Detailed reference viewed: 111 (33 ULiège)
Full Text
Peer Reviewed
See detailDevelopment of a contact model adapted to incremental forming
Henrard, Christophe ULiege; Bouffioux, Chantal ULiege; Godinas, A. et al

in Banabic, D. (Ed.) Proceedings of the 8th ESAFORM Conference on Material Forming (2005)

The objective of this article is to present the development of a new method for taking into account the contact between the tool and the blank during incremental forming. First, the need for such a model ... [more ▼]

The objective of this article is to present the development of a new method for taking into account the contact between the tool and the blank during incremental forming. First, the need for such a model is justified. Then, the basic features of the adapted dynamic explicit scheme are presented, followed by the new algorithms proposed and their programming. Finally, some conclusions and perspectives are drawn. [less ▲]

Detailed reference viewed: 103 (8 ULiège)
Peer Reviewed
See detailDevelopment of a cost calculation module for the inland and sea-river waterway transport
Marchal, Jean ULiege; Kicheva, D.

in Proceedings of the PIANC Conference on Inland and Maritime navigation and Coastal Problems of East European Countries (1996, September)

Detailed reference viewed: 17 (0 ULiège)
Full Text
Peer Reviewed
See detailDevelopment of a Cough Induction Test in Pigs: Effects of Sr 48968 and Enalapril
Moreaux, B.; Beerens, Dominique ULiege; Gustin, Pascal ULiege

in Journal of Veterinary Pharmacology & Therapeutics (1999), 22(6), 387-389

Detailed reference viewed: 55 (0 ULiège)
Full Text
See detailDevelopment of a coupled flow and transport 3D model for simulating seawater intrusions in coastal aquifers
Carabin, Guy; Dassargues, Alain ULiege

in Natuurwetenschappelijk Tijdschrift (1999), 79

Detailed reference viewed: 27 (5 ULiège)
Full Text
See detailDevelopment of a database linked to a GIS for coupling with groundwater modelling tools
Ruthy, Ingrid ULiege; Orban, Philippe ULiege; Gogu, Radu Constantin et al

in Iu (Ed.) Computational Methods in Engineering and Science (2003)

Groundwater analysis strongly depends on the availability of large volumes of high-quality data. Putting all data in a coherent and logical structure supported by a computing environment helps ensure ... [more ▼]

Groundwater analysis strongly depends on the availability of large volumes of high-quality data. Putting all data in a coherent and logical structure supported by a computing environment helps ensure validity and availability and provides a powerful tool for hydrogeological studies. A hydrogeological Geographical Information System (GIS) database that offers facilities for hydrogeological modeling has been designed in Belgium for the Walloon Region. Interest is growing in the potential for integrating GIS technology and groundwater simulation models. A “loose-coupling” tool was created between the spatial database scheme and the groundwater numerical model interface GMS© (Groundwater Modeling System). Following time and spatial queries, the hydrogeological data stored in the database can be easily used within different groundwater numerical models. [less ▲]

Detailed reference viewed: 62 (12 ULiège)
Full Text
Peer Reviewed
See detailDevelopment of a Database System for the Management of Borehole Data : Experience and lessons
Halleux, Isabelle ULiege

in Mathematical Geology (1994), 26(7), 833-841

CBS-LOG is a multilingual database system for the management of coal exploratory borehole data. It is a dBase application running on PC's with minimum configurations. Developing a suitably accurate ... [more ▼]

CBS-LOG is a multilingual database system for the management of coal exploratory borehole data. It is a dBase application running on PC's with minimum configurations. Developing a suitably accurate database requires some stratégic choices and lots of discussions and compromises between experts. The experience shows that it is absolutely necessary to follow strictly the development flow-sheet and that the difficulties rely mainly on communication and human aspects of mathematical geology. A step by step approach is reviewed in terms of experience and lessons. [less ▲]

Detailed reference viewed: 10 (0 ULiège)
Full Text
Peer Reviewed
See detailDevelopment of a decision support system for setting up a wind energy policy across the Walloon Region (southern Belgium)
Lejeune, Philippe ULiege; Feltz, Claude ULiege

in Renewable Energy : An International Journal (2008), 33

Wallonia (the region covering southern Belgium) is committed to making a significant increase in its wind-powered electricity production capacity by 2010. Therefore, a decision support system designed to ... [more ▼]

Wallonia (the region covering southern Belgium) is committed to making a significant increase in its wind-powered electricity production capacity by 2010. Therefore, a decision support system designed to evaluate and map environmental and landscape constraints fundamental to the building of wind farms was developed for the whole Walloon Region (17,000 km2). This system is a geodatabase using 40 criteria (landscape or environmental) corresponding to three constraint levels (exclusion, highly sensitive and sensitive). This geodatabase also has analysis functions developed in the ArcGIS 9 software environment that are used to update the overall constraints map, to analyse sensitivity with respect to constraint criteria-defining parameters as well as to perform full diagnostic studies on wind farm projects. [less ▲]

Detailed reference viewed: 116 (21 ULiège)
Full Text
See detailDevelopment of a decision-making tool to manage forest storm damage in the Walloon Region (Belgium)
Riguelle, Simon ULiege; Jourez, Benoît ULiege; Hebert, Jacques ULiege

Poster (2008, June 03)

When an unexpected windthrow event occurs, the extent of damage may rapidly increase to reach a crisis level. Therefore, it requires a suitable and fast reaction by the public authorities and the ... [more ▼]

When an unexpected windthrow event occurs, the extent of damage may rapidly increase to reach a crisis level. Therefore, it requires a suitable and fast reaction by the public authorities and the concerned owners as well as by the whole sector of wood transformation. The aim of this research, which is a regional priority, relates to the realization of a decision-making tool thought not under the constraint of the urgency, when trees are lying down on the ground, but established on the basis of real dramatic cases already experienced in the past. The tool is dedicated to political and administrative services but, to be effective, calls upon a broad collaboration with all the partners of the wood sector. [less ▲]

Detailed reference viewed: 20 (9 ULiège)
Full Text
See detailDevelopment of a didactic SPH model
Goffin, Louis ULiege

Master's dissertation (2013)

The SPH method (smoothed particle hydrodynamics) is a numerical meshless, particle and Lagrangian method. It is used in a lot of fields of engineering, such as solids mechanics, hydraulics and ... [more ▼]

The SPH method (smoothed particle hydrodynamics) is a numerical meshless, particle and Lagrangian method. It is used in a lot of fields of engineering, such as solids mechanics, hydraulics and astrophysics. The medium is represented thanks to a set of particles that have an influence on each other. First of all, the positioning of the method is discussed. The SPH method is compared to some existing numerical methods. Its advantages and drawbacks are introduced. Its particle, meshless and Lagrangian characteristics are compared to other existing methods. The basics of the method are explained through the integral representation of a function and the particle approximation. Moreover, some smoothing functions are analysed. The SPH method being Lagrangian, the Navier-Stokes equations must be written in the Lagrangian formalism. After this, the SPH method can be applied to the equations of continuity and of conservation of momentum. Some practical issues linked to the SPH method such as the neighbours search, the equations of state or the boundary conditions are discussed. Then, the practical implementation of the method and of the chosen options is explained in details. An object-oriented programming was chosen for its advantages in comparison to a classical sequential implementation. Finally, the implemented program is tested and commented. Its advantages are highlighted and its drawbacks are discussed and explained. There are a lot of test cases presented. They include some validation tests (dam breaks, particles fall, etc.), some test cases used to compare the options of the program and other tests present the possibilities of the code. [less ▲]

Detailed reference viewed: 434 (74 ULiège)
See detailDevelopment of a Diesel Substitute Fuel
Reiter, A M; Mair-Zelenka, P; Wallek, T et al

in 9th International Colloquium Fuels - Conventional and Future Energy for Automobiles (2013)

Detailed reference viewed: 13 (0 ULiège)
Peer Reviewed
See detailDevelopment of a digital accelerometer for low-frequency structural vibration measurement
Kraft, Michaël ULiege; Lewis, Christopher P.; Hesketh, Thomas G.

in The 1996 Sensor and Transducer Conference Proceedings (1996)

Detailed reference viewed: 9 (1 ULiège)
Peer Reviewed
See detailThe development of a digital accelerometer
Lewis, Christopher P.; Kraft, Michaël ULiege; Hesketh, Thomas G.

in Proceedings 27th ISATA - International Symposium on Automotive Technology and Automation (1994)

Detailed reference viewed: 14 (0 ULiège)
Full Text
See detailDEVELOPMENT OF A DISCRETE EVENT SIMULATION BASED TOOL FOR OFFSHORE LOGISTICS IN WIND FARM INSTALLATION
Muhabie, Yohannes Tekle ULiege

Doctoral thesis (2016)

The o shore wind energy development has shown a progress in the last ten years. Distance from the coast and the depth of the water are increasing continuously. The transport and installation of o -shore ... [more ▼]

The o shore wind energy development has shown a progress in the last ten years. Distance from the coast and the depth of the water are increasing continuously. The transport and installation of o -shore wind turbines is highly dependent on weather condition at sea. Delaying an activity in the logistics chain could have a signi cant impact on overall project completion. Hence there is a need to have a well-organized and thoroughly analyzed planning of the overall processes starting from the producers sites until the o shore site where the turbines will be installed. The weather conditions and the installation strategies are the major limit factors in uencing the o shore wind farm installations. In this thesis a Discrete Event Simulation (DES) based tool has been developed for o shore logistics in wind farm installation. It takes into account the weather restriction limits (wind speed and wave height), distance matrix, vessel characteristics and installation strategies. The logistics model maps out the activities of the o shore wind farm installations. Both historical and probabilistic weather data approaches have been implemented, analyzed and compared. The results indicated that the probabilistic approach is highly a ected by the random seed numbers used to set up the stochastic behavior of the input variable. Application of the developed tools to real O shore Wind Farm (OWF) con guration illustrated that there is a good agreement between the results obtained from the two approaches. However, it has been identi ed that the probabilistic approach may slightly underestimate the project lead time compared to the results obtained using historical data. Furthermore, weather downtime and sensitivity analysis have been carried out for di erent weather scenarios in order to identify the parameters that a ect the logistic chain signi cantly during the o shore wind farm installation. In this context, it is indicated that the lifting operation (limited by wind speed) causes the highest down time compared to other activities and improving the lifting operations could result in a signi cant reduction (10-15 %) in the overall project completion time. In conclusion, overall analysis indicated that the application of a DES tool improves the decision support system including the planning and control of the logistics processes of the o shore wind farm installation, reducing the associated risks. [less ▲]

Detailed reference viewed: 31 (5 ULiège)
Peer Reviewed
See detailDevelopment of a Dynamic 3-D Nonlinear Computer Program
Fonder, Ghislain ULiege; Charlier, Robert ULiege; Habraken, Anne ULiege et al

in Convention Européenne de la Construction métallique (1986)

Detailed reference viewed: 45 (5 ULiège)
Peer Reviewed
See detailDevelopment of a dynamic guidance model for car drivers in the city center of Liège, Belgium.
Marchal, Jean ULiege; Ndiaye, Alassane-Ballé ULiege

in Proceedings of the INFORMS Montreal Spring meeting 1998 (1998)

Detailed reference viewed: 14 (1 ULiège)