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See detailCharacterisation of sand transport in gravel-bed rivers using iron slag dated by historical studies
Houbrechts, Geoffrey ULg; Levecq, Yannick; Petit, François ULg

Poster (2012, April 25)

Considerable quantities of iron-smelting slag are present in the bed of the Ardennian rivers. These waste products come from hundreds of ironworks (mainly blast furnaces and finery forges) built close to ... [more ▼]

Considerable quantities of iron-smelting slag are present in the bed of the Ardennian rivers. These waste products come from hundreds of ironworks (mainly blast furnaces and finery forges) built close to different-sized rivers between the 14th and the 19th centuries. In general, slag was crushed by hammers, sorted and piled up in heaps around the furnaces, generally onto the floodplains. Furthermore, some archives mention that they were sometimes thrown out directly into the rivers. This means that for centuries, slag elements have been swept away by floods, mixed with the sediment and spread out along river courses. Due to their distinctive appearance, slag particles are easily recognizable among the natural elements. Thanks to many historical studies conducted on the early iron industry, we are able to date quite precisely the inception and the periods of activity of the different sites established in the catchments. These data are indispensable in order to use slag as a tracer to quantify the particles’ velocity in rivers. Downstream of ironworks, samples of sand have been collected in the surface layer of many gravel-bed rivers. Then, the slag concentration of each sample has been measured in the coarse sand fraction. The representation of the longitudinal evolution of slag concentration in these rivers permits the dispersion of slag to be analysed, the relative bed-material discharges at confluences to be quantified and the velocity of coarse sand to be determined. A survey of the bedload discharge in the Ardennian rivers established that more than 90 % of the bedload transport consists of coarse sand grains that are transported on the bottom of the bed. However, in the literature, this grain-size fraction is generally not considered in bedload discharge estimations because the sandy particles are very difficult to tag and to recover. Consequently, the huge amounts of slag injected in rivers several centuries ago can be considered as a very useful opportunity to characterise the sand transport in gravel-bed rivers. [less ▲]

Detailed reference viewed: 21 (0 ULg)
See detailCharacterisation of silica low-density xerogels in presence of additives by image analysis and nitrogen adsorption-desorption
Blacher, Silvia ULg; Alié, Christelle ULg; Gommes, Cédric ULg et al

in Characterization of Porous Solids VI (2002)

Micro- and mesopore structure modifications in silica low-density xerogels induced by additives in TEOS-based alcogels precursors are discussed on the basis of image analysis of transmission electron ... [more ▼]

Micro- and mesopore structure modifications in silica low-density xerogels induced by additives in TEOS-based alcogels precursors are discussed on the basis of image analysis of transmission electron microscopy (TEM) micrographs and nitrogen adsorption-desorption experiments. To perform image analysis, novel image processing has been developed on the basis of classical signal treatment and mathematical morphology theory. The obtained results have been correlated with classical and fractal interpretation of nitrogen adsorption-desorption measurements. [less ▲]

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See detailCharacterisation of stability behaviour of ultra fine alumina powder in view its colloidal processing by gel-casting
Gaydardzhiev, Stoyan ULg; Ay, P.

in Onal G. et al. (Ed.) Proceedings of XXIII International Mineral Processing Congress, 3-8 September 2006, Istanbul (2006, September)

The paper reports on results study aimed at assessing of the influence of dispersant type on the electrochemical properties of highly concentrated alumina suspension. The relationship between the type of ... [more ▼]

The paper reports on results study aimed at assessing of the influence of dispersant type on the electrochemical properties of highly concentrated alumina suspension. The relationship between the type of dispersant and the stabilization ability towards ultrafine alumina powder CT3000 has been studied. The effectiveness was determined mainly by the zeta potential value, specific surface charge, the shift in the pH(iep) and by visual controlling the fluidity of the slurry at constant solid loading. A good agreement between the zeta potential and the specific surface charge as a way to determine the optimal dose of dispersant has been documented. Gel-casting experiments showed that the Dolapix CE64, an ammonium polyacrylate dispersant was the best dispersant for the studied powder. [less ▲]

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See detailCharacterisation of structural determinants and molecular mechanisms involved in Stromelysin-3 activation by 4-aminophenylmercuric acetate and furin-type convertases.
Santavicca, M.; Noël, Agnès ULg; Stoll, I. et al

in Biochemical Journal (1996), 315

Stromelysin-3 (ST3) is a matrix metalloproteinase (MMP) which has been implicated in cancer progression and in a number of conditions involving tissue remodelling. In contrast to other MMPs which are ... [more ▼]

Stromelysin-3 (ST3) is a matrix metalloproteinase (MMP) which has been implicated in cancer progression and in a number of conditions involving tissue remodelling. In contrast to other MMPs which are secreted as zymogens requiring extracellular activation, ST3 is found in the extracellular space as a potentially active mature form, suggesting that the activation of the ST3 proform differs from that of other MMPs. We show in the present study that the ST3 proform is not autocatalytically processed in the presence of 4-aminophenylmercuric acetate (APMA). By using ST3/ST2 chimeras, we demonstrate that resistance to APMA is due to properties associated with both the ST3 pro- and catalytic domains. In agreement with the observation made by Pei and Weiss [Pei and Weiss (1995) Nature (London) 375, 244-247], we find that the requirement for activation of the ST3 proform by the furin convertase is entirely contained within a stretch of 10 amino acids located at the junction between the ST3 pro- and catalytic domains. Furin cleaves human and mouse ST3 equally well. However, PACE-4, a furin-like convertase, is much more efficient on the mouse enzyme, suggesting that ST3 protein determinants other than the conserved Ala-Arg-Asn-Arg-Gln-Lys-Arg sequence preceding the furin cleavage site are implicated in PACE-4 action. Finally, we show that processing of the ST3 proform is inhibited by a furin inhibitor in human MCF7 breast cancer cells stably transfected to constitutively express a full-length human ST3 cDNA. Using brefeldin A, we demonstrate that, in these MCF7 cells, the 56 kDa precursor form of ST3 is post-translationally modified in the cis- or media-Golgi into a 62 kDa proform. Thereafter, its processing into the 47 kDa mature form occurs in the trans-Golgi network and is followed by secretion into the extracellular space. [less ▲]

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See detailCharacterisation of the acute and reversible airway inflammation induced by cadmium chloride inhalation in healthy dogs and evaluation of the effects of salbutamol and prednisolone.
Bolognin, M.; Kirschvink, N.; Leemans, Jérôme ULg et al

in Veterinary Journal (2009), 179(3), 443-450

The aims of this study were firstly to characterise a model of subclinical and reversible bronchial inflammation induced by cadmium chloride inhalation in healthy dogs and then to examine the effect of ... [more ▼]

The aims of this study were firstly to characterise a model of subclinical and reversible bronchial inflammation induced by cadmium chloride inhalation in healthy dogs and then to examine the effect of prednisolone or salbutamol treatment on the resulting bronchitis. The model characterisation and the effects of treatment were studied using clinical symptoms, haematology, thoracic radiography, bronchoscopy and bronchoalveolar lavage, barometric whole-body plethysmography and histamine broncho-provocation tests. In addition, the activity of matrix metalloproteinases (MMP)-2 and -9 were determined in serum and bronchoalveolar lavage fluid (BALF). Cadmium inhalation induced: (1) a transient bronchial inflammation, dominated by neutrophils; (2) a neutrophilia of the blood that persisted for up to 4weeks; (3) a transient increased bronchial reactivity, and (4) a significant increase in MMP-9 activity in the BALF. Prednisolone treatment reduced the influx of inflammatory cells into the BALF, but not significantly, had no effect on pulmonary function, and did not reduce of airway hypersensitivity. Salbutamol had almost no effect on any of the parameters investigated. [less ▲]

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See detailCharacterisation of the joint properties by means of the component method
Jaspart, Jean-Pierre ULg; Steenhuis, M.; Anderson, D.

in Proceedings of the COST C1 International Conference (1998)

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See detailCharacterisation of the magnetic shielding properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates
Denis, Samuel; Grenci, G.; Dusoulier, Laurent et al

in Journal of Physics: Conference Series (2006), 43

This communication reports experimental results on the superconducting properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates. The magnetic shielding properties of ... [more ▼]

This communication reports experimental results on the superconducting properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates. The magnetic shielding properties of the coatings were characterised by various methods. First, the electrical resistance and the transport critical current density, Jc, were determined. Our coatings exhibit a superconducting transition at a temperature of 90 K. Next, shielding characterisations were carried out at 77 K for samples having either a slab or a cylindrical geometry. In both cases, the frequency of the applied magnetic field was 103 Hz; the field behind the shielding wall was measured by a pick-up coil connected to a lock-in amplifier. In the case of cylindrical samples and for an applied induction lower than 1 G, the field inside the shielding enclosure is reduced by a factor greater than 106 (i.e. 120 dB) with respect to the applied field. [less ▲]

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See detailCharacterisation of the noise emitted by the passage of a passenger cruise liner in the Venice lagoon: concern about possible effects on the local fish community
Picciulin, Marta; Bolgan, Marta ULg; Codarin, Antonio et al

in Annales. Series Historia Naturalis (2013), 23(2),

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See detailCharacterisation of thermophysical properties of semi-solid steels for thixoforming
Lecomte-Beckers, Jacqueline ULg; Rassili, Ahmed ULg; Carton, Marc ULg et al

in Proceedings of the 8th International Conference on Semi-Solid Processing of Alloys and Composites (S2P) (2004)

Major challenge for semi-solid processing includes broadening the range of alloys that can be successfully thixoformed and developing alloys specifically for thixoforming. One important parameter is ... [more ▼]

Major challenge for semi-solid processing includes broadening the range of alloys that can be successfully thixoformed and developing alloys specifically for thixoforming. One important parameter is appropriate solidus-liquidus interval. The wider the solidification interval, the wider the processing window. This study is related to the experimental determination of this critical parameter on eight different steel compositions. This parameter was obtained using Differential Scanning Calorimetry. This technique allows to obtain the solid fraction versus temperature. The paper also presents the results of thermophysical properties determination such as thermal diffusivity, heat capacity and thermal conductivity. These properties were measured from room temperature to semi-solid state in one particular steel. The thermal diffusivity was measured using the Laser Flash method and the heat capacity using a DSC calorimeter. The thermal conductivity was obtained by calculation knowing the thermal dilatation measured with a dilatometer. All these measurements were performed for temperatures up to the liquidus. These parameters are difficult to measure but they are important to determine for the conductive heating phase of a semi-solid forming (SSM) process. [less ▲]

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See detailCharacterisation of TLR7/8 in equine pulmonary alveolar macrophages
Tosi, Irène ULg; Frellstedt, Linda; Pirottin, Dimitri ULg et al

Poster (2015, October 08)

Purpose of the study: In both human and equine athletes, viral infections are common causes of respiratory diseases and of a sudden deterioration of expected performances. In both species, the underlying ... [more ▼]

Purpose of the study: In both human and equine athletes, viral infections are common causes of respiratory diseases and of a sudden deterioration of expected performances. In both species, the underlying mechanisms are still unclear, and an involvement of Toll-Like Receptors (TLRs), a fundamental link between innate and adaptive immunity, has been advocated. Our objectives were to verify the presence of TLR7 and TLR8, responsible for the early anti-viral response in mammals, in equine pulmonary alveolar macrophages (PAMs) and to assess their function through specific stimulation. Methods used: Equine PAMs were collected by broncho-alveolar lavage (BAL), isolated by adherence and stimulated with specific TLR7/8 ligands (an imidazoquinoline compound and single-stranded RNA), mimicking a viral attack. The expression of TLR7/8 was evaluated by rt-PCR and the ligand-induced production of cytokines (type I-IFNs and TNF-α) was assessed via ELISA. Summary of results: Our study demonstrated the expression of TLR7/8 in equine PAMs. QPCR analyses showed a high relative expression of genes coding for TLR7 and TLR8 on equine PAM. Stimulation with specific TLR7/8 ligands resulted in significantly up-regulated production of IFN-β and TNF-α, thereby confirming that TLR7/8 are functional in equine PAMs and that they play a role in the early pulmonary antiviral response. Conclusions: This study shows that TLR7 and TLR8 are present and functional in equine PAM and that they could play a role in the early pulmonary antiviral response. In terms of future perspectives, it is interesting to suggest that the extensively demonstrated efficacy of TLR7 and TLR8 synthetic ligands in the treatment of viral diseases in human medicine could motivate the pursuit of clinical trials in the equine patient for the therapeutic management or prevention of viral respiratory infections. [less ▲]

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See detailCharacterisation of TRIP-assisted steel by atomic force microscopy and OIM
Ros-Yanez, Tanya; Houbaert, Yvan; Petrov, Roumen et al

in De Cooman, Bruno C. (Ed.) Proceedings of the International Conference on TRIP-Aided High-Strength Ferrous Alloys (2002, June)

TRIP-assisted steel has a complicated microstructure, obtained through well designed heat treatments and consisting of different phases, mainly ferrite, retained austenite, bainite and martensite. The ... [more ▼]

TRIP-assisted steel has a complicated microstructure, obtained through well designed heat treatments and consisting of different phases, mainly ferrite, retained austenite, bainite and martensite. The drastic influence of microstructure on physical and mechanical properties makes metallographic examination a necessity for property understanding and enhancement. A fairly simple tint etching procedure (LePera method) using light microscopy and SEM observation ensures the distinction of ferrite, bainite and retained austenite/martensite grains. Nevertheless, the etching is not selective enough to allow a distinction between retained austenite and martensite. Atomic force microscopy was used for the phase identification and characterisation of this kind of steel. A series of tests was performed using AFM-contact mode and magnetic force microscopy in C-Mn-Si and C-Mn-Al TRIP-assisted steel after intercritical annealing followed by ageing, After ageing, some samples were tempered in order to make metallographic observation easier. It has been possible to identify the different phases and their topographic characteristics and to study their morphology using AFM. Orientation imaging microscopy was used to calibrate the observations done with AFM, distinguishing between bcc- and fcc-zones and quantify the retained austenite. [less ▲]

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See detailCharacterising and Exploiting Workloads of Highly Interactive Video-on-Demand
Brampton, Andrew; MacQuire, Andrew; Fry, Michael et al

in Multimedia Systems (2009)

This paper presents a detailed character- isation of user behaviour for a series of interactive video experiments over a 12 month period, in which we served popular sporting and musical content. In ad ... [more ▼]

This paper presents a detailed character- isation of user behaviour for a series of interactive video experiments over a 12 month period, in which we served popular sporting and musical content. In ad- dition to generic VCR-like features, our custom-built Video-on-Demand application provides advanced inter- activity features such as bookmarking. The dramatic impact of such functionality on how users consume con- tent is studied and analysed. We discuss in detail how this user behaviour can be exploited by content dis- tributors to improve user experience. Speci cally, we study how simple dynamic bookmark placement and interactivity-aware content pre-fetching and replication can reduce the impact of highly interactive media on CDN performance. [less ▲]

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See detailCharacterising the spectra of spray droplets on three artificial targets using image analysis.
Degre, Aurore ULg; Mostade, Olivier; Huyghebaert, Bruno et al

in Mededelingen van de Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen (Rijksuniversiteit te Gent) (2000), 65(2b),

Detailed reference viewed: 24 (6 ULg)
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See detailCharacterising urban morphology with spectral unmixing and spatial metrics: a case study on Dublin
Canters, Frank; Van de Voorde, Tim; Binard, Marc ULg et al

in Proceedings of the 24th International Cartographic Conference (ICC 2009), (2009)

In today’s urbanising world, effective urban management and planning strategies are needed to temper the impact of urban change processes on the natural and human environment. To develop and monitor such ... [more ▼]

In today’s urbanising world, effective urban management and planning strategies are needed to temper the impact of urban change processes on the natural and human environment. To develop and monitor such strategies, and to assess their spatial impact, analysing changes in urban structure is essential. Data from earth observation satellites provide regular information on urban development and, as such, may contribute to the mapping and monitoring of cities and the modelling of urban dynamics. Especially images of medium resolution (Landsat, SPOT, …), which are cheap, widely available and often part of extensive historic archives, offer a wealth of information that may be useful for urban monitoring purposes. The lower resolution of this type of imagery, however, hampers the study of urban morphology and change processes at a more detailed, intra-urban level. Spectral unmixing approaches, which allow characterising land-cover distribution at sub-pixel level, may partly compensate for this lack of spatial detail, and may render medium-resolution imagery more useful for urban studies. The main research question addressed in this paper is how medium-resolution imagery could be used to describe urban morphology, by combining spectral unmixing approaches with spatial metrics. Spatial metrics derived from satellite imagery may be useful to quantify structural characteristics of expanding cities, and may provide indications of functional land use. In this study, we develop a set of urban metrics for use on continuous sealed surface data produced by sub-pixel classification of Landsat ETM+ imagery. Two sub-pixel classification approaches are examined for that purpose. In a first approach, we use a linear spectral mixture model with a vegetation and a non-vegetation endmember to deconvolve each pixel’s spectrum into fractional abundances of the two end member spectra, which are determined by visualising mixture space with principal component analysis. In a second approach, we use a linear regression model to estimate the proportion of vegetation cover within each Landsat pixel. In both approaches, an urban mask is used to indicate pixels belonging to urban land cover. Only pixels within the urban mask are subjected to sub-pixel classification. We hereby assume that the urban area does not contain bare soil and that the area of a pixel not covered by vegetation fully consists of sealed surface cover. The resulting sealed surface proportion map is then used to characterise urban morphology and land use by means of the shape of the cumulative frequency distribution of the estimated sealed surface fractions within a building block. A transformed logistic function is fitted to this distribution with a least-squares approach to obtain function parameters that are used as variables in a supervised classification approach, together with spatially explicit metrics (spatial variance and Moran’s I). Our study demonstrates that images from medium resolution sensors can be used to characterise intra-urban morphology, and that the structure of a building block as described by the proposed metrics gives an indication of its membership to certain morphological/functional urban classes. In future research we will incorporate socio-economic data in the metric analysis to further improve the distinction of urban land-use categories. The spatial metrics approach developed in this study will be used in experiments to improve the calibration of the MOLAND urban growth model, which is currently calibrated with historical land-use maps available for approximately 10-year intervals. [less ▲]

Detailed reference viewed: 113 (8 ULg)