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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 past and future climate changes on the distribution of three Southeast Asian murine rodents
Latinne, Alice ULg; Meynard, Christine; Herbreteau, Vincent et al

in Journal of Biogeography (2015), 42(9), 1714-1726

Aim: We tested the influence of Pleistocene climatic fluctuations and the potential effect of future climate change on Southeast Asian small mammal distributions using two forest-dwelling (Leopoldamys ... [more ▼]

Aim: We tested the influence of Pleistocene climatic fluctuations and the potential effect of future climate change on Southeast Asian small mammal distributions using two forest-dwelling (Leopoldamys herberti and Leopoldamys sabanus) and one karst (Leopoldamys neilli) endemic rodent species as models. Location: Southeast Asia. Methods: We used presence–absence data of genetically identified individuals, bioclimatic variables and species distribution modelling techniques to predict potential distributions of the three studied species under current, past [Last Interglacial (LIG) and Last Glacial Maximum (LGM)] and future conditions. We applied a variety of modelling techniques and then used consensus techniques to draw up robust maps of potential distribution ranges at all stages. Results: According to our models, these three Leopoldamys species did not experience significant range contraction during the LGM. Our models revealed substantial range contraction during the LIG for L. herberti in northern Indochina, while its distribution expanded in southern Indochina. Evidence of a southward range expansion during that period was also obtained for L. neilli, whereas L. sabanus remained widely distributed in insular Southeast Asia but experienced a range contraction on the Thai-Malay Peninsula. The two future climate change scenarios used predicted that large climatically suitable areas would still be available in the future for the three species. Main conclusions: Our model predictions contradict the well-established hypothesis that Southeast Asian forest-dwelling species were confined to small refugia during the LGM. Moreover, our results suggest that some Southeast Asian taxa may have been distributed in their refugial state during the LIG rather than the LGM. This could be because of vegetation changes that may have occurred at that time as a result of the increased seasonality observed during the LIG. These Pleistocene refugia may have been localized in northern Indochina but our study also revealed that southern Indochina could provide major potential refugia. [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 plant roots on electrical resistivity measurements of cultivated soil columns
Maloteau, Sophie ULg; Blanchy, Guillaume ULg; Javaux, Mathieu et al

Poster (2016, April)

The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil ... [more ▼]

The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil column. For this research, it is assumed that roots system affect the electrical properties of the rhizosphere. Indeed the root activity (by transporting ions, releasing exudates, changing the soil structure,…) will modify the rhizosphere electrical conductivity (Lobet G. et al, 2013). This experiment is included in a bigger research project about the influence of roots system on geophysics measurements. Measurements are made on cylinders of 45 cm high and a diameter of 20 cm, filled with saturated loam on which seeds of Brachypodium distachyon (L.) Beauv. are sowed. Columns are equipped with electrodes, TDR probes and temperature sensors. Experiments are conducted at Gembloux Agro-Bio Tech, in a growing chamber with controlled conditions: temperature of the air is fixed to 20°C, photoperiod is equal to 14 hours, photosynthetically active radiation is equal to 200 µmol m-2s-1, and air relative humidity is fixed to 80 %. Columns are fully saturated the first day of the measurements duration then no more irrigation is done till the end of the experiment. [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

Detailed reference viewed: 48 (7 ULg)