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
See detailImprovements of an iterative and staggered Approach for a Model of Mixed Lubrication in Cold Rolling
STEPHANY; Ponthot, Jean-Philippe ULg

in Proceedings of NUMIFORM 2004, The 8th International Conference on Numerical Methods in Industrial Forming Processes: Materials processing and design. Modeling, Simulation and Applications (2004)

Detailed reference viewed: 9 (1 ULg)
Full Text
Peer Reviewed
See detailImprovements of image processing for wheat ear counting
Cointault, Frédéric; Journaux, Ludovic; Miteran, Joel et al

in Agricultural and biosystems engineering for a sustainable world (2008)

One of the most important activity of agricultural research insititutes concerns the agronomical experiments done under different conditions needing many land observations and valuations to quantify ... [more ▼]

One of the most important activity of agricultural research insititutes concerns the agronomical experiments done under different conditions needing many land observations and valuations to quantify several variables. These observations, although generally accurate, are visually done by the agriculturist technicians and present numerous drawbacks: penibility, weak productivity, numerous labor force, limited sampling … Two feasibility studies lead in our laboratory recently have shown that some of the previous observations, and particularly the counting of the number of wheat ear per m², can be done by color and/or texture image processing for images taken directly in the field with a specific acquisition system. This paper describes the improvements of the previous studies concerning the image acquisition system, and especially the illumination control, and the justification of different hypothesis on the number of classes to detect in an image. The use of a cluster validity index has allowed to prove that 3 classes to determine all the objects in a wheat ear image are not sufficient. A correlation with a study based on the size of the analysis window is currently under investigation to improve the ear detection, which is now of 6%, compared to manual counting done by agriculturist technicians. [less ▲]

Detailed reference viewed: 46 (4 ULg)
Full Text
See detailImprovements of some analysis methods for flight flutter test data using unsteady aerodynamic considerations
Dimitriadis, Grigorios ULg

in Proceedings of the 2003 International Forum on Aeroelasticity and Structural Dynamics (2003, June)

To date the analysis of data from ight utter tests is routinely carried out under the assumption of steady or, at best, quasi-steady aerodynamics. This approach is favored mainly because of its simplicity ... [more ▼]

To date the analysis of data from ight utter tests is routinely carried out under the assumption of steady or, at best, quasi-steady aerodynamics. This approach is favored mainly because of its simplicity. In this paper it is shown that, even for some very simple simulated aeroelastic systems, utter predictions that ignore the unsteadiness of aerodynamic loads can be signi cantly inaccurate. Then, two simple system identi cation techniques are proposed that can model both the steady and unsteady aerodynamic loads acting on an aeroelastic system in incompressible ow. These methods can be used in order to obtain a complete description of an aeroelastic system subject to unsteady aerodynamic forces, including its dependence on ight conditions. Finally, the new methods are applied to a simple simulated unsteady aeroelastic model. The resulting utter predictions are compared to those obtained from two standard ight utter test data analysis approaches and are shown to be signi cantly more accurate. [less ▲]

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailImproving 3D measurements accuracy with camera information redundancy
Schwartz, Cédric ULg; Fringuellini, Anthony ULg; Bruls, Olivier ULg et al

Conference (2011, July)

The accuracy of the Codamotion system for 3D measurement depends mainly on the signal level of the sensors and the resolution of the system at the marker localization. When using several units to cover a ... [more ▼]

The accuracy of the Codamotion system for 3D measurement depends mainly on the signal level of the sensors and the resolution of the system at the marker localization. When using several units to cover a large field of view, the estimated position of the different units might differ. We propose a method taking both resolution and signal level in to account, instead of only the signal level as in the built-in weighting process. This new method offers improved accuracy. [less ▲]

Detailed reference viewed: 90 (28 ULg)
Full Text
Peer Reviewed
See detailImproving bioethanol production by increasing sugar beet crop yield
Belboom, Sandra ULg; Léonard, Angélique ULg

in CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources (2011), 6(24), 1-10

This review presents a summary of published papers about the improvement of sugar beet yield and its transformation into bioethanol. After situating the current political and economic context of the sugar ... [more ▼]

This review presents a summary of published papers about the improvement of sugar beet yield and its transformation into bioethanol. After situating the current political and economic context of the sugar beet crop, influence of factors during the crop growth is studied. Main factor influencing the crop yield and, consequently the bioethanol yield is the weather variability. Others parameters as climate change, fertilizer and crop management are evocated and explained in further paragraphs. Irrigation takes also place in semi-arid countries and plays a role in the different results. After the overview of the crop growth conditions, the sugar beet transformation into bioethanol has been pointed out with the most energetic steps, the different available raw materials from sugar beet and the optimal parameters to get the highest possible yield in terms of bioethanol. To provide economics on bioenergy production, the goal is to obtain the highest yield available in terms of sugar beet, sugar and then bioethanol. Some savings can be made with energy reduction during the fermentation or distillation steps. A sole guideline to reach this goal is not available because of the variability of the parameters depending on the location and on the weather forecasts. [less ▲]

Detailed reference viewed: 95 (15 ULg)
See detailImproving control of storage diseases on apple by combining biological and physical postharvest methods
Creemers, P.; Van Laer, S.; Vorstermans, B. et al

Poster (2006)

Detailed reference viewed: 9 (0 ULg)
See detailImproving education for disadvantaged children: some Belgian studies
Osterrieth, Paul A.; De Coster, W.; Burion, J. et al

Book published by Pergamon Press/Van Leer (1977)

Detailed reference viewed: 12 (2 ULg)
Full Text
Peer Reviewed
See detailImproving effect of metal and oxide nanoparticles encapsulated in porous silica on fermentative biohydrogen production by Clostridium butyricum.
Beckers, Laurent; Hiligsmann, Serge ULg; Lambert, Stéphanie ULg et al

in Bioresource Technology (2013), 133C

This paper investigated the enhancement effect of nanometre-sized metallic (Pd, Ag and Cu) or metallic oxide (Fe(x)O(y)) nanoparticles on fermentative hydrogen production from glucose by a Clostridium ... [more ▼]

This paper investigated the enhancement effect of nanometre-sized metallic (Pd, Ag and Cu) or metallic oxide (Fe(x)O(y)) nanoparticles on fermentative hydrogen production from glucose by a Clostridium butyricum strain. These nanoparticles (NP) of about 2-3nm were encapsulated in porous silica (SiO(2)) and were added at very low concentration (10(-6)molL(-1)) in batch hydrogen production test. The cultures containing iron oxide NP produced 38% more hydrogen with a higher maximum H(2) production rate (HPR) of 58% than those without NP or with silica particles only. The iron oxide NP were used in a 2.5L sequencing-batch reactor and showed no significant effect on the yields (established at 2.2mol(hydrogen)mol(glucose)(-1)) but an improvement of the HPR (+113%, reaching a maximum HPR of 86mL(hydrogen)L(-1)h(-1)). These results suggest an improvement of the electron transfers trough some combinations between enzymatic activity and inorganic materials. [less ▲]

Detailed reference viewed: 98 (25 ULg)
Full Text
Peer Reviewed
See detailImproving energy efficiency of existing suburban areas through district energy planning
Marique, Anne-Françoise ULg; Reiter, Sigrid ULg

in Proceedings of ISHVAC 2011 (2011, November)

Urban sprawl represents a significant contribution to the overall energy consumption of a territory for energy needs in buildings and for transport. It is a huge concern in Belgium where public ... [more ▼]

Urban sprawl represents a significant contribution to the overall energy consumption of a territory for energy needs in buildings and for transport. It is a huge concern in Belgium where public authorities face the following question: “what to do with existing low-density districts that require a lot of resources?” while households still continue to favour this kind of dwellings. In this context, the paper draws up a typological classification of reference Walloon suburban blocks. Then, energy savings relating to several types of renewal strategy are evaluated. These strategies deal with the measures to reduce heat demand in buildings, to increase the built density and to reduce energy consumption in the transport sector. Results from this analysis show that a strong potential exists to improve energy efficiency in existing suburban districts. Building insulation and travel distances are critically important factors. Solar gains on the roofs are huge even if the built density is increased. [less ▲]

Detailed reference viewed: 64 (11 ULg)
Full Text
Peer Reviewed
See detailImproving functional performance and muscle power 4-to-6 months after anterior cruciate ligament reconstruction
Souissi, Sabrine; Wong, Del P.; Dellal, Alexandre et al

in Journal of Sports Science & Medicine (2011), 10

Detailed reference viewed: 30 (4 ULg)
Peer Reviewed
See detailImproving Generalization for 3D Object Categorization with Global Structure Histograms
Madry, Marianna; Ek, Carl Henrik; Detry, Renaud ULg et al

in IEEE/RSJ International Conference on Intelligent Robots and Systems (2012)

Detailed reference viewed: 18 (0 ULg)
Peer Reviewed
See detailIMPROVING GENOMIC PREDICTION BY EUROGENOMICS COLLABORATION
Lund, M. S.; de Roos, A. P. W.; de Vries, A. G. et al

in Proceedings of the 9th World Congress on Genetics Applied to Livestock Production (2010)

Detailed reference viewed: 72 (0 ULg)
Peer Reviewed
See detailImproving groundwater flow model conceptualisation and calibration with electrical resistivity tomography and self-potential methods
Robert, Tanguy ULg; Therrien, René; Lemieux, Jean-Michel et al

Conference (2011, September 19)

Developing a conceptual model for groundwater flow requires knowledge on the distribution of geological materials, which generally comes from geological observations on outcrops and boreholes, from the ... [more ▼]

Developing a conceptual model for groundwater flow requires knowledge on the distribution of geological materials, which generally comes from geological observations on outcrops and boreholes, from the interpretation of hydraulic tests or from geophysical surveys. The identification of spatial structures in the subsurface, such as preferential flow paths created by fractured zones, is also critical in developing a reliable conceptual model but it is difficult to achieve. Geophysical methods have been widely used to map the subsurface distribution of geological materials. Recent developments in geophysics, such as the increased use of joint inversion of geophysical and hydrogeological data, have further allowed to quantify the hydraulic conductivity of geological materials. The objective of our work is to demonstrate that the electrical resistivity tomography (ERT) and the self-potential (SP) methods can improve both the conceptual model developed for groundwater flow systems and the calibration of the corresponding groundwater flow model. The use of the two geophysical methods, combined with a groundwater flow model, is presented for a fractured limestone aquifer. The self-potential method relies on passive measurements of the ambient electrical potential at ground surface or in boreholes. One of the mechanisms responsible for the measured signal measured is the transport of dissolved ions with groundwater flow. When this electrokinetic effect is the dominant contribution, the resulting signal is called the streaming potential and it contains information about groundwater fluxes that can be useful to calibrate groundwater flow models. The solution to the SP forward problem was added to the HydroGeoSphere model, which simulates 3D groundwater flow and solute transport in porous media, including fractured geological formations. With this addition, the model can calculate the self-potential signal associated with groundwater flow, given the distribution of Darcy fluxes resulting from the forward flow solution and the electrical resistivity that is, for example, outputted by ERT data inversion. Darcy fluxes are transformed into sources of electrical current by using the streaming potential coupling coefficient. This parameter can be measured either in the laboratory or in-situ from the self-potential signal between two locations where the depth of the water table is known, such as observation wells. We used here both ERT and SP to develop a conceptual model for groundwater flow in a typical carboniferous limestone syncline in South Belgium. The rolling topography in the investigated area results from a succession of calcareous valleys (synclines) and sandstone crests (anticlines). The calcareous synclines form aquifers that are very complex since they are highly fractured and even karstified. A typical calcareous syncline has a width of about 800 m and, using ERT, we could subdivide the syncline into zones of different hydraulic conductivity, based on the degree of fracturation. The zones are oriented along the axis of the syncline and their width ranges between 10 and 40 m. The ERT profiles showed that there is a highly conductive zone, in terms of electrical conductivity, near the syncline fold axis. That zone is interpreted as being highly fractured. Other conductive zones are located symmetrically along both flanks of the calcareous syncline, with respect to the syncline fold axis. The main flow direction is along the axis of the syncline, towards a nearby river. The SP raw signals also showed that, locally, there is a second flow component perpendicular to the axis of the syncline, with groundwater flowing from the flanks of the syncline towards the axis. The conceptual groundwater flow model developed here includes the zones identified with ERT, which were then incorporated into the numerical model. The SP signals were inverted with PEST to calibrate the hydraulic conductivity value of the different zones. HydroGeoSphere was therefore used to simulate first groundwater flow and then the associated self-potential signals in an iterative process. At the start of an iteration, HydroGeoSphere solves the groundwater flow equation given one particular set of hydraulic conductivities and calculates the resulting Darcy fluxes. These fluxes are transformed into sources of electrical current assuming that the electrokinetic effect is the dominant contribution of the SP signals. HydroGeoSphere then calculates the distribution of self-potential given the sources of electrical current and the distribution of electrical resistivity. The hydraulic conductivity values of the zones are then modified and the iteration continues until the model reproduces the measured self-potential signal. [less ▲]

Detailed reference viewed: 86 (9 ULg)
Full Text
Peer Reviewed
See detailImproving Groundwater Flow Model Conceptualisation and Calibration with ERT and Self-potential Methods
Robert, Tanguy ULg; Therrien, René; Lemieux, Jean-Michel et al

in EarthDoc - Near Surface 2011 – 17th European Meeting of Environmental and Engineering Geophysics (2011, September 14)

The self-potential (SP) method relies on passive measurements of the ambient electrical potential at the ground surface or in boreholes. When the electrokinetic effect is the dominant contribution, the ... [more ▼]

The self-potential (SP) method relies on passive measurements of the ambient electrical potential at the ground surface or in boreholes. When the electrokinetic effect is the dominant contribution, the resulting signal is called the streaming potential and contains information about groundwater fluxes that can be useful for calibration of groundwater flow models. The streaming potential forward equation was implemented in the HydroGeoSphere model, which simulates 3D groundwater flow and solute transport in porous media, including fractured geological formations. HydroGeoSphere is able to calculate the streaming potential given a distribution of Darcy velocity and electrical resistivity. Since groundwater flow modelling relies on a conceptual model, prior information on the distribution of the geological units and hydraulic conductivity at the site is mandatory. However, this information is often scarce or missing. In this work, we use the electrical resistivity tomography (ERT) and the SP methods as an additional source of information for building the groundwater flow model. ERT is used to identify the location of fractured zones in a fractured and karstified calcareous aquifer of South Belgium. The SP signal is used with PEST in order to calibrate the groundwater flow model and better constrain the hydraulic conductivity of the fractured zones. [less ▲]

Detailed reference viewed: 49 (9 ULg)
Full Text
Peer Reviewed
See detailImproving halva quality with dietary fibres of sesame seed coats and date pulp, enriched with emulsifier
Elleuch, Mohamed; Bedigian, Dorothea; Maazoun, Bouthaina et al

in Food Chemistry (2014), 145

Supplementation of halva with waste products of manufacturing, for example defatted sesame seed coats (testae) and date fibre concentrate, can improve its nutritional and organoleptic qualities. These ... [more ▼]

Supplementation of halva with waste products of manufacturing, for example defatted sesame seed coats (testae) and date fibre concentrate, can improve its nutritional and organoleptic qualities. These constituents provide high fibre content and technological potential for retaining water and fat. Standard halva supplemented with date fibre concentrate, defatted sesame testae and emulsifier was evaluated for oil separation, texture and colour changes, sensory qualities and acceptability to a aste panel. Addition of both fibres with an emulsifier, improved emulsion stability and increased the hardness of halva significantly. The functional properties of sesame testae and date fibres promote nutrition and health, supplying polyphenol antioxidants and laxative benefits. [less ▲]

Detailed reference viewed: 24 (0 ULg)
Full Text
Peer Reviewed
See detailImproving in-row weed detection in multispectral stereoscopic images
Piron, Alexis ULg; Leemans, Vincent ULg; Lebeau, Frédéric ULg et al

in Computers & Electronics in Agriculture (2009), 69

Previous research has shown that plant height and spectral reflectance are relevant features to classify crop and weeds in organic carrots: classification based on height gave a classification accuracy ... [more ▼]

Previous research has shown that plant height and spectral reflectance are relevant features to classify crop and weeds in organic carrots: classification based on height gave a classification accuracy (CA) of up to 83% while classification based on a combination of three multispectral bands gave a CA of 72%. The first goal of this study was to examine the simultaneous use of both height and multispectral parameters. It was found that classification rate was only slightly improved when using a feature set comprising both height and multispectral data (2%). The second goal of this study was to improve the detection method based on plant height by setting an automatic threshold between crop and weeds heights, in their early growth stage. This threshold was based on crop row determination and peak detection in plant height probability density function, corresponding to the homogeneous crop population. Using this method, the CA was 82% while the CA obtained with optimal plant height limits is only slightly higher at 86%. [less ▲]

Detailed reference viewed: 88 (21 ULg)