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See detailInfluence of Particle Packing on Fracture Properties of Concrete
He, Huan ULg; Stroeven, Piet; Stroeven, Martijn et al

in Computers and Concrete (2011), 8(6), 677-692

Particle packing on meso-level has a significant influence on workability of fresh concrete and also on the mechanical and durability properties of the matured material. It was demonstrated earlier that ... [more ▼]

Particle packing on meso-level has a significant influence on workability of fresh concrete and also on the mechanical and durability properties of the matured material. It was demonstrated earlier that shape exerts but a marginal influence on the elastic properties of concrete provided being packed to the same density, which is not necessarily the case with different types of aggregate. Hence, elastic properties of concrete can be treated as approximately structure-insensitive parameters. However, fracture behaviour can be expected structure-sensitive. This is supported by the present study based on discrete element method (DEM) simulated three-phase concrete, namely aggregate, matrix and interfacial transition zones (ITZs). Fracture properties are assessed with the aid of a finite element method (FEM) based on the damage materials model. Effects on tensile strength due to grain shape and packing density are investigated. Shape differences are shown to have only modest influence. Significant effects are exerted by packing density and physical-mechanical properties of the phases, whereby the ITZ takes up a major position. [less ▲]

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See detailInfluence of particle shape on size distribution measurements by 3D and 2D image analyses and laser diffraction
Califice, Arnaud ULg; Michel, Frédéric ULg; Dislaire, Godefroid ULg et al

in Powder Technology (2013), 237

This paper highlights the fact that particle size distribution (PSD) is not unique for the same product, and is dependent on the chosen measurement technique, especially for asymmetric shapes. Laser ... [more ▼]

This paper highlights the fact that particle size distribution (PSD) is not unique for the same product, and is dependent on the chosen measurement technique, especially for asymmetric shapes. Laser diffraction and 2D image analysis are commonly used PSD measurement techniques. However, the resultsmay not be representative of the true physical dimensions of the particles. The influence of particle shape on PSD results obtained from 2D/3D image analysis and laser diffraction was investigated. Two metallic powders presenting extreme shape properties (round and elongated particles) were analyzed, as well as a blend of the two pure products. 2D image analysis and laser diffraction results were compared to 3D image analysis (measuring the true particle size). This paper compares the PSD results obtained from the three methods. Some commonly used size parameters in image analysis software did not give meaningful results in regard of the true physical dimensions of the particles. The existence of the two populations (products with extremely different shape and size characteristics) could not be identified with such size parameters, and laser diffraction also performed poorly. The PSD obtained from more precise size parameters (image analysis) better corresponded to the true dimensions of the particles. This study highlights the strengths and weaknesses of particle size analysis techniques when studying products presenting diverse particle shapes, and points out that caution is required in the choice of the size parameters, and in the interpretation of PSD results. [less ▲]

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See detailThe influence of particle size distribution on sunflower tahini rheology and structure
Mureşan, Vlad; Danthine, Sabine ULg; Racolţa, Emil et al

in Journal of Food Process Engineering (2014)

Different particle size sunflower tahini prototypes were obtained by controlling the milling process of roasted sunflower kernels. Not only the physicochemical properties of these samples but also of an ... [more ▼]

Different particle size sunflower tahini prototypes were obtained by controlling the milling process of roasted sunflower kernels. Not only the physicochemical properties of these samples but also of an industrial reference were compared and discussed in order to understand tahini behavior and structure. Granulometry was determined by a laser-scattering analyzer and revealed for all studied samples, trimodal particle size distributions. Histogram modes, as well as cumulative volume percentages (CVPs) of smal l- and middle-class populations, increased with the number of passes through colloidal mill, while for large particle size population, both the modes and CVPs decreased. Pseudoplastic behavior was observed for all sunflower tahini prototypes and reference, irrespective of studied temperature and particle size. However, the value of consistency coefficient ranged from 3,049 to 6.6 Pa·s n being strong dependent on particle size and temperature while flow behavior indexes between 0.53 and 0.87. Time-dependent rheological analysis revealed higher thixotropic degree of coarser sunflower tahini samples. Studied samples had rheological properties characteristic for a viscoelastic mate- rial, the response in the dynamic frequency sweep being typical for weak gels. The finest sunflower tahini prototype showed the lowest Krieger–Dougherty estimated volume fraction (0.48), while the coarsest sample the highest (0.69), sunflower tahini reference being placed in a median position with a volume fraction of 0.56. By combining all those data, a schematic structure of sunflower tahini was pro- posed for the first time [less ▲]

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See detailInfluence of permanent use of feeding stalls as living area on ammonia and greenhouse gas emissions for group-housed gestating sows kept on straw deep-litter
Philippe, François-Xavier ULg; Laitat, Martine ULg; Wavreille, José et al

in Livestock Science (2013), 155

In pig production, the interest for litter systems in relation with animal welfare and the ban by 2013 in the EU of individual accommodations for gestating sows could promote the group-housing of ... [more ▼]

In pig production, the interest for litter systems in relation with animal welfare and the ban by 2013 in the EU of individual accommodations for gestating sows could promote the group-housing of gestating sows on deep-litter. However, compared to slatted-floor systems, few data are available on the gaseous emissions associated with the different modalities of rearing sows on deep-litter. In this study, two modalities were compared: group housing on a 3 m2/sow deep-litter or on a 1.8 m2/sow deep-litter plus 1.2 m2/sow concrete floor. In both cases, sows were fed in individual feeding stalls (1.2 m2/stall) but the access was limited at feeding time in the first case and permanent in the second one. Three successive batches of 10 gestating sows were used. Each batch was divided into 2 homogeneous groups randomly allocated to one of two treatments: fully (3 m2/sow) or partly (1.8 m2/sow) straw-based deep-bedded floor. The groups were kept separately in two identical rooms with same volume and same surface, equipped with five individual feeding stalls in contact with a pen of either 9 or 15 m2 deep-litter. The feeding stalls were equipped with front feeding troughs and rear gates allowing or not permanent access to the stalls outside of feeding times. Between each batch, the pens were cleaned. In both rooms, ventilation was automatically adapted to maintain a constant ambient temperature. The gas emissions (nitrous oxide, methane, carbon dioxide, ammonia and water vapour) were measured 3 times (weeks 2, 5 and 8 of stay) during 6 consecutive days by infrared photoacoustic detection. Sow performance was not significantly affected by floor type. With sows kept on partly bedded floor, gaseous emissions were significantly greater for methane (12.76 vs. 9.90 g/d.sow; P<0.001), carbon dioxide (3.12 vs. 2.90 kg/d.sow; P<0.01) and water vapour (4.70 vs. 4.03 kg/d.sow; P<0.001), and significantly lower for nitrous oxide (3.14 vs. 6.12 g/d.sow; P<0.001) and CO2 equivalents (1.24 vs. 2.10 kg/d.sow; P<0.001) compared to sows housed on fully bedded floor. There was no significant difference for ammonia emissions (8.36 vs. 7.45 g/d.sow; P>0.05). From the present trial in experimental rooms, it can be concluded that keeping group-housed gestating sows on partly straw bedded floor with permanent access to the concrete feeding stalls compared to fully straw bedded floor did not significantly influence animal performance and NH3-emissions, and decreased CO2eq-emissions (-40%). This decrease was observed owing to an important decrease of N2O-emissions (-49%). [less ▲]

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See detailThe Influence of Phylogenic Origin on the Occurrence of Brachycephalic Airway Obstruction Syndrome in a Large Retrospective Study
Njikam Nsangou, Ibrahim ULg; Huault, Maxime; Pirson, Vincent et al

in International journal of applied research in veterinary medicine (2009), 7(3), 138-143

Strategies to identify genetic polymorphisms responsible for inherited disorders in purebred dog population are often based on experimental studies whereas hospitals case reports provide widely and easily ... [more ▼]

Strategies to identify genetic polymorphisms responsible for inherited disorders in purebred dog population are often based on experimental studies whereas hospitals case reports provide widely and easily affordable information of clinical significance. When this clinical information is enriched with knowledge on the phylogenetic origins, breed histories of the dog and adjusted for known biases, they may lead the way to more in depth genetic research. We illustrated here with a very complex disease, the brachycephalic airway obstruction syndrome (BAOS). No cases were reported in the boxer breed while almost half of the dogs from the other brachycephalic breeds of the same phylogenetic cluster were BAOS, making these breeds good candidates for further genetic studies. Critical issues to improve utility of clinical data for genetic studies are discussed along with methods to handle biases inherent to such type of studies. [less ▲]

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See detailInfluence of physico-chemical characteristics of limestone fillers on fresch and hardened mortar performances
Michel, Frédéric ULg; Piérard, Julie; Courard, Luc ULg et al

in De Schutter, G.; Boel, V. (Eds.) Self-Compacting Concrete SCC 2007 (2007, September)

In order to meet the specific requirements for fresh Self-Compacting Concrete (SCC), i.e. a high workability together with a good resistance to segregation, the amount of coarse aggregates has to be ... [more ▼]

In order to meet the specific requirements for fresh Self-Compacting Concrete (SCC), i.e. a high workability together with a good resistance to segregation, the amount of coarse aggregates has to be reduced and replaced by fine material. Since cement is quite expensive and can develop a high heat of hydration with possible problems for thermal cracks in massive concrete, mineral fillers are usually used. In Belgium, local available materials are limestone fillers; they are very well-adapted for the optimisation of particle packing and flow behaviour of cementitious paste in SCC mixes. These by-products are issued from different sectors, such as the aggregate and lime production industry (quarrying operations) and the ornamental stones industry (sawing operations). The suitability of these fillers for use in SCC or conventional concrete production was investigated. This paper reports the effect of the nature and the substitution rate of the fillers on the properties of mortars. Some relationship between the physico-chemical properties of the fillers and the properties of mortars were brought forward. [less ▲]

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See detailInfluence of Plasminogen Activator Inhibitor Type 1 on Choroidal Neovascularization
Lambert, Vincent ULg; Munaut, Carine ULg; Frankenne, F. et al

in FASEB Journal (2001), 15(6), 1021-7

High levels of the plasminogen activators, but also their inhibitor, plasminogen activator inhibitor 1 (PAI-1), have been documented in neovascularization of severe ocular pathologies such as diabetic ... [more ▼]

High levels of the plasminogen activators, but also their inhibitor, plasminogen activator inhibitor 1 (PAI-1), have been documented in neovascularization of severe ocular pathologies such as diabetic retinopathy or age-related macular degeneration (AMD). AMD is the primary cause of irreversible photoreceptors loss, and current therapies are limited. PAI-1 has recently been shown to be essential for tumoral angiogenesis. We report here that deficient PAI-1 expression in mice prevented the development of subretinal choroidal angiogenesis induced by laser photocoagulation. When systemic and local PAI-1 expression was achieved by intravenous injection of a replication-defective adenoviral vector expressing human PAI-1 cDNA, the wild-type pattern of choroidal angiogenesis was restored. These observations demonstrate the proangiogenic activity of PAI-1 not only in tumoral models, but also in choroidal experimental neovascularization sharing similarities with human AMD. They identify therefore PAI-1 as a potential target for therapeutic ocular anti-angiogenic strategies. [less ▲]

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See detailInfluence of players' level on racket speed and ball accuracy in the tennis serve
Tubez, François ULg; Croisier, Jean-Louis ULg; Cordonnier, Caroline ULg et al

Conference (2014, July 06)

INTRODUCTION Serve in modern tennis game is an important offensive weapon for players (1-2). In kinematic analysis, serve is the most studied stroke of this game. The aim of our study was to compare the ... [more ▼]

INTRODUCTION Serve in modern tennis game is an important offensive weapon for players (1-2). In kinematic analysis, serve is the most studied stroke of this game. The aim of our study was to compare the performance of two specific populations: international players versus national players. In particular, racket speed at impact and accuracy of ball were assessed. METHODS A tennis court was reconstructed in a motion analysis laboratory. The position of the racket was evaluated in 3D at a frequency rate of 200 Hz. Tests were performed on 6 professional players (international level) and 9 non-professional players (national level). Each of them served 25 trials in direction of the “T” area of deuce diagonal. Two squares of 1m² and 2 m² respectively were delimited on the corner of the serve square. The instruction for both groups was to serve in the “T” area with the highest ball speed and minimal ball rotation (flat serve). RESULTS Although the forward speed of the racket at impact was identical between the two groups of players (International 36.35 ± 2.37 m/s and national 36.37 ± 2.90 m/s, p-value 0,991), the accuracy and consistency of serves on the target area is better for international players group (1m² area: International 33% ± 7% and national 14% ± 12%, p-value 0.0053; 2m² area (including 1m² area): International 71% ± 8% and national 54% ± 12%, p-value 0.0096; Out of zone: International 29% ± 8% and national 46% ± 12%, p-value 0.014). DISCUSSION High-velocity ball seems to be a key factor for serve performance (3). It is known that there is a relationship between racket speed and ball velocity (4). Both groups have high racket speed. However, international players serve with better accuracy and consistency than national players. We hypothesize that these differences are due to capacity of international players to adapt to a particular environment. Moreover, international players could give priority to consistency over velocity. We conclude that high-velocity serve is not a sufficient criterion to perform at international level; consistency and accuracy are two important factors to reach this level. [less ▲]

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See detailInfluence of practice characteristics on injury risk in young athletes
Frisch, Anne ULg; Urhausen, Axel; Seil, Romain et al

in British Journal of Sports Medicine (2011), 45

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See detailInfluence of practice characteristics on injury risk in young athletes
Frisch, Anne; Urhausen, A.; Seil, R. et al

in British Journal of Sports Medicine (2011, April), 45

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See detailInfluence of processing parameters on physicochemical properties of low-trans and trans-free puff pastry margarines
Lefebure, Emilie ULg; Ronkart, Sébastien; Brostaux, Yves ULg et al

in LWT - Food Science and Technology (2013), 51(1), 225-232

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See detailInfluence of progesterone concentrations on secretory functions of trophoblast and pituitary during the first trimester of pregnancy in dairy cattle
Ayad, A.; Melo de Sousa, Noelita ULg; Sulon, Joseph ULg et al

in Theriogenology (2007), 67(9), 1503-1511

The essential role played by progesterone in the maintenance of pregnancy is unequivocal; however, the effects of progesterone on the secretory patterns of placental and pituitary molecules during the ... [more ▼]

The essential role played by progesterone in the maintenance of pregnancy is unequivocal; however, the effects of progesterone on the secretory patterns of placental and pituitary molecules during the gestation period are not well defined. The objective of this study was to describe pregnancy-associated glycoprotein (PAG) concentrations (measured by RIA-497 and RIA-Pool) in pregnant females with progesterone concentrations lower (low-P4 group, n = 20) or higher (high-P4 group, n = 17) than the mean of 8.74 ng/mL on Day 21 (AI = Day 0). Luteinizing hormone (LH) and prolactin concentrations were also measured in both groups. Throughout the study period, blood samples were collected on Days 0, 21, 45, 60, and 80 from 37 females that were confirmed to be pregnant. PAG concentrations measured by both RIA-497 and RIA-Pool tended to be higher in high-P4 group than in low-P4 group from Day 30 until Day 80. On Day 80, plasma PAG concentrations that were measured using RIA-497 were observed to be higher (P < 0.05) in the high-P4 group than in the low-P4 group (10.2 +/- 8.7 ng/mL versus 6.9 +/- 13.8 ng/mL). Concentrations of LH on Day 60 and prolactin on Day 80 were observed to be significantly lower (P < 0.05) in the high-P4 group. There was a tendency for the concentrations of LH (Days 45 and 80) and prolactin (Days 30, 45, and 60) to be lower in cows in the high-P4 group than in the low-P4 group. Our results suggest the existence of a relationship among the concentration levels of progesterone, PAG, LH, and prolactin during early pregnancy. (C) 2007 Elsevier Inc. All rights reserved. [less ▲]

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