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See detailThe mechanical effects of short-circuit currents in substations with flexible conductors. Numerical Methods - Computer Approach.
Lehmann, Werner; Lilien, Jean-Louis ULg; Orkisz, J.

in Proceedings of CIGRE 1982 (1982, September 01)

A review of the application of advanced computer methods to the evaluation of the mecanical effects caused by the electromagnétic forces associated with short-circuit currents.

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See detailMechanical effects of short-circuit currents in substations with strain bus systems. Medium complexity calculation methods.
Gauffin, Louis; Lilien, Jean-Louis ULg

in Proceedings of the CIGRE Symposium 06-85 (1985)

This paper details various methods (medium complexity) for calculation of conductor tensions and displacements of substation under short-circuit loading.

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See detailMechanical effects of short-circuit currents in substations with strain bus systems. Parameter Analysis and simple method of calculation.
Lilien, Jean-Louis ULg; Brokamp, Luc

in Proceedings of the CIGRE Symposium 06-85 (1985, June)

SImple methods to evaluate short-circuit mechanical effects in substation.

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See detailMechanical evaluation of a thermoplastic casting material.
Claeys, Stéphanie ULg; Meuron, M.; Boeraeve, P. et al

in Veterinary Record : Journal of the British Veterinary Association (2007), 161(7), 238-40

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See detailMechanical Flow Obstruction after Heart Transplantation Diagnosed by Tee
CANIVET, Jean-Luc ULg; DEFRAIGNE, Jean ULg; Demoulin, Jean-Claude et al

in Annals of Thoracic Surgery (1994), 58(3), 890-1

We report a case of mechanical flow obstruction after heart transplantation caused by a prominent left atrium suture with a "pursestring" effect. The diagnosis was achieved by transesophageal ... [more ▼]

We report a case of mechanical flow obstruction after heart transplantation caused by a prominent left atrium suture with a "pursestring" effect. The diagnosis was achieved by transesophageal echocardiography. The mean transstenotic gradient was measured at 13 mm Hg. Because of the profound hemodynamic and multisystemic failure, no surgical correction was attempted. The postmortem examination confirmed the stenosis at the level of the left atrium. [less ▲]

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See detailMechanical loading affects angiogenesis and osteogenesis in an in vivo bone chamber: a modeling study.
Geris, Liesbet ULg; Vandamme, Katleen; Naert, Ignace et al

in Tissue Engineering. Part A (2010), 16(11), 3353-3361

Despite a myriad of studies confirming the interaction between biology and mechanics, the exact nature of the main mechanical stimuli and their influence on the bone regeneration processes are still ... [more ▼]

Despite a myriad of studies confirming the interaction between biology and mechanics, the exact nature of the main mechanical stimuli and their influence on the bone regeneration processes are still unclear. The hypothesis of this study was that the outcome of peri-implant healing under different implant loading regimens can be explained by the influence of fluid flow on the combination of angiogenesis and osteogenesis through its influence on cell proliferation and differentiation. To investigate this hypothesis a mathematical model of bone regeneration was applied to simulate the peri-implant healing in an in vivo repeated sampling bone chamber for different axial micromechanical implant loading regimes. When mechanical loading was modeled to influence both osteogenic and angiogenic processes, a good agreement was observed between simulations and experiments concerning the amount of bone in the bone chamber, its radial and longitudinal distribution, and the bone-implant contact for different implant displacement magnitudes. [less ▲]

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See detailMechanical loading highly increases IL-6 production and decreases OPG expression by osteoblasts.
Sanchez, Christelle ULg; Gabay, Odile; Salvat, Colette et al

in Osteoarthritis and Cartilage (2009), 17(4), 473-81

OBJECTIVES: In osteoarthritis (OA), mechanical factors play a key role, not only in cartilage degradation, but also in subchondral bone sclerosis. The aim of this study was to develop on original ... [more ▼]

OBJECTIVES: In osteoarthritis (OA), mechanical factors play a key role, not only in cartilage degradation, but also in subchondral bone sclerosis. The aim of this study was to develop on original compression model for studying the effect of mechanical stress on osteoblasts. MATERIALS AND METHODS: We investigate the effects of compression on primary calvaria osteoblasts isolated from newborn mice and cultured for 28 days in monolayer. At the end of this period, osteoblasts were embedded in a newly synthesized extracellular matrix which formed a three-dimensional membrane. This membrane was then submitted to compression in Biopress Flexercell plates (1-1.7 MPa compressions at 1 Hz frequency) during 1-8h. The expression of 20 genes was investigated by real time reverse transcriptase polymerase chain reaction. Interleukin (IL)-6, matrix metalloproteinase (MMP)-3 and prostaglandin (PG)E(2) were assayed in the culture medium by specific immunoassays. RESULTS: The compression highly increased IL-6 and cyclooxygenase (COX)-2 mRNA levels in osteoblasts. In parallel, increased amount of IL-6 and PGE(2) was found in the supernatant of loaded osteoblasts. This stimulation reached a maximum after 4h of 10% compression. MMP-2, MMP-3, and MMP-13 mRNA levels were also increased by compressive stress, while 15-hydroxyprostaglandin-dehydrogenase and osteoprotegerin (OPG) start to decrease at hour 4. COX-1, microsomial PG E synthase-1 (mPGES1), mPGES2 and cytosolic PGES and receptor activator of nuclear factor ligand (RANKL) were unmodified. Finally, we observed that alpha 5 beta 1 integrin, intracellular Ca(++), nuclear factor-kappaB and extracellular signal-regulated kinase 1/2 pathways were involved in the compression-induced IL-6 and PGE(2) production. IL-6 neutralizing antibodies and piroxicam inhibited the decrease OPG expression, but did not modify RANKL mRNA level, indicating that IL-6 and PGE(2) induce a decrease of the OPG/RANKL ratio. CONCLUSION: This work demonstrates that IL-6 is mechano-sensitive cytokine and probably a key factor in the biomechanical control of bone remodeling in OA. [less ▲]

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See detailMechanical loads on overhead lines bundle conductors
Lamchich, Moulay; El Adnani, Mustapha; Lilien, Jean-Louis ULg

in Proceedings of the 6th ESCC (1994, September)

Power lines subject to short-circuit mechanical loading may include budle collapse and pinch effect.A numerical investigation is performed and test comparisons are detailed.

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See detailMechanical loads on substation apparatuses
Lilien, Jean-Louis ULg; Schon, Ulrich

in Proceedings of the 6th ESCC (1994, September)

Short-circuit mechanical effects in substations are of particular concern. Their dynamic behaviour may sensibly influence the response of the structure to these dynamic loadings.

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See detailMECHANICAL PRETREATMENT EFFECT ON CELLULOSE ENZYMATICAL HYDROLYSIS
Jacquet, Nicolas ULg; Paquot, Michel ULg

Poster (2008)

Lignocellulosic materials are very interesting for the production of bioethanol after chemical or enzymatical hydrolysis of cellulose. To optimise production rate and increase the output of these ... [more ▼]

Lignocellulosic materials are very interesting for the production of bioethanol after chemical or enzymatical hydrolysis of cellulose. To optimise production rate and increase the output of these processes, different kinds of pre-treatments (grinding, steam explosion…) are often needed for opening the fibrous structure of the cellulose and increase the specific surface of the materials. The present study is focused on two models of “pure” cellulose (cellulose C200 microtechnik, cellulose FD100 FMC biopolymer) in order to analyse the effects of mechanical pretreatments on the kinetics and yields of hydrolysis. The cristallinity index differentiates the two celluloses. Hydrolysis is realized by a cellulase mix (cellulase Trichoderma reesei C2730, Novozyme; cellobiase Aspergillus niger C6105). Results present the influence of homogenisation pretreatment and analyse differents parameters of this technology. [less ▲]

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See detailMechanical Processes of a Single Synthetic Molecular Machine Studied by AFM-based Force Spectroscopy
Lussis, Perrine ULg

Doctoral thesis (2012)

Some biomolecules are able to generate directional forces by rectifying random thermal motions. This allows these molecular machines to perform mechanical tasks such as intracellular cargo transport or ... [more ▼]

Some biomolecules are able to generate directional forces by rectifying random thermal motions. This allows these molecular machines to perform mechanical tasks such as intracellular cargo transport or muscle contraction in plants and animals. Although some artificial molecular machines have been synthesized and used collectively to perform mechanical tasks, so far there have been no direct measurements of mechanical processes at the single-molecule level. Here we report measurements of the mechanical work performed by a synthetic molecule less than 5 nm long. We show that biased Brownian motion of the submolecular components in a hydrogen-bonded [2]rotaxane -a molecular ring threaded onto a molecular axle- can be harnessed to generate significant directional forces. We used the cantilever of an atomic force microscope to apply a mechanical load to the ring during single-molecule pulling-relaxing cycles. The ring was pulled along the axle, away from the thermodynamically favoured binding site, and was then found to travel back to this site against an external load of 30 pN. Using fluctuation theorems, we were able to relate the measurements of the work done at the level of individual molecules to the free energy change measured previously by ensemble measurements. Finally, we used dynamic single-molecule force spectroscopy to probe kinetic information of the interaction between the molecular ring and the preferred binding site. The results also demonstrate that AFM-based single-molecule force spectroscopy, which has been widely used to investigate the mechanochemical behaviour of (bio)macromolecules, can be applied to a molecule that is less than 5 nm in its extended form. [less ▲]

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See detailMechanical properties and recrystallisation behaviour of Fe base ODS alloys
Lecomte-Beckers, Jacqueline ULg; Coutsouradis, D.; Lecomte-Mertens, Ch. et al

in Proceedings of PM'94, Congrès mondial de Métallurgie des Poudres (1994)

Developments in higher temperature exchangers and other applications require high strength as well as oxidation resistance at very high temperature. In order to meet such requirements, Dour Metal has ... [more ▼]

Developments in higher temperature exchangers and other applications require high strength as well as oxidation resistance at very high temperature. In order to meet such requirements, Dour Metal has developed ODM new range of oxide dispersion strengthened (ODS) iron base alloys realised by powder mechanical alloying. Compositional and thermomechanical manipulations can be used to develop the structure enabling the service temperature to be increased up to about 1200°C. An optimization of the structure is required to obtain the best high temperature creep resistance. This consist in minimizing the grain densities and the misorientation between adjoining grains. The paper will discuss some results on evolution of the texture during different thermomechanical treatments on ODS Fe base tubes. Typical rupture strength will be presented for temperature ranging from 900 to 1100°C. The emphasis will be given to alloy ODM 751 which most recent work has been performed. [less ▲]

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See detailMechanical properties of Al/Al2O3 nanolaminated films: correlation to microstructure
Ben Daia, M.; Aubert, P.; Labdi, S. et al

in Surface & Coatings Technology (2000), 125(1-3), 196-200

Wear resistance and the hardness of Al/Al2O3 nanolaminated films were investigated in this study. Monolithic films and multilayers were deposited on a silicon substrate with two different substrate ... [more ▼]

Wear resistance and the hardness of Al/Al2O3 nanolaminated films were investigated in this study. Monolithic films and multilayers were deposited on a silicon substrate with two different substrate temperatures: T-s= 25 degrees C and T-s= -90 degrees C. The period thickness of multilayers was lowering from 40 to 2 nm. From nanoindentation measurements, it appears that the hardness of multilayers has an intermediate value between those of metal (Al) and ceramic (Al2O3). The tribological test was conducted by the pin-on-disc method. The T-s=25 degrees C deposited multilayers, as well as single films, demonstrated poor wear resistance. The best wear resistance was obtained for multilayers deposited at the lowest substrate temperature (T-s= -90 degrees C). The results are ill good agreement with structural characterization. X-ray reflectometry demonstrated that the multilayer character of Al/Al2O3 is more pronounced for T-s= -90 degrees C. (C) 2000 Elsevier Science S.A. All rights reserved. [less ▲]

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See detailMechanical properties of alloy Ti-6Al-4V and of stainless steel 316L processed by Selective Laser Melting: Influence of out-of-equilibrium microstructures
Mertens, Anne ULg; Reginster, Sylvie ULg; Paydas, Hakan ULg et al

in Powder Metallurgy (2014), 57(3), 184-189

Ti-6Al-4V and stainless steel 316L have been processed by selective laser melting under similar conditions, and their microstructures and mechanical behaviours have been compared in details. Under the ... [more ▼]

Ti-6Al-4V and stainless steel 316L have been processed by selective laser melting under similar conditions, and their microstructures and mechanical behaviours have been compared in details. Under the investigated conditions, Ti-6Al-4V exhibits a more complex behaviour than stainless steel 316L with respect to the occurrence of microstructural and mechanical anisotropy. Moreover, Ti-6Al-4V appears more sensitive to the build-up of internal stresses when compared with stainless steel 316L, whereas stainless steel 316L appears more prone to the formation of “lack of melting” defects. This correlates nicely with the difference in thermal conductivity between the two materials. Thermal conductivity was shown to increase strongly with increasing temperature and the thermophysical properties appeared to be influenced by variations in the initial metallurgical state. [less ▲]

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See detailMechanical properties of excised calf lungs
Gustin, Pascal ULg; Lekeux, Pierre ULg; Lomba, F. et al

in Research in Veterinary Science (1987), 42(3), 272-276

Five isolated calf lungs were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure (Ptp). The static pressure-volume ... [more ▼]

Five isolated calf lungs were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure (Ptp). The static pressure-volume curve characteristics of the lungs were measured. Static compliance (Cstat) was 1.9 +/- 0.37 litres kPa-1 or 25 +/- 5 per cent of total lung capacity kPa-1. At a Ptp of 0.7 kPa, dynamic compliance (Cdyn) and lung resistance (RL) were 1.1 +/- 0.1 litres kPa-1 and 0.126 +/- 0.02 kPa litres sec-1, respectively. Both an increase and a decrease of this level of Ptp induced an increase of RL and a decrease of Cdyn. The ratio Cdyn/Cstat averaged 57 +/- 0.8 per cent. It was concluded that in excised lungs, Cdyn is lower in the calf than in a number of other species and that pulmonary function values measured in vitro are optimum at values of Ptp close to values recorded in vivo in healthy cattle [less ▲]

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See detailMechanical properties of excised calf lungs: effects of airway obstruction with beads
Gustin, Pascal ULg; Lekeux, Pierre ULg; Lomba, F. et al

in Research in Veterinary Science (1987), 42(3), 277-279

Isolated lungs of five calves were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure. Dynamic compliance (Cdyn) and ... [more ▼]

Isolated lungs of five calves were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure. Dynamic compliance (Cdyn) and total pulmonary resistance (RL) were measured. These pulmonary function values were also measured during central and peripheral airway obstructions. It was demonstrated that both central and peripheral obstructions induced significant variations of Cdyn and RL. However, decrease of Cdyn was greater and increase of RL was smaller during a peripheral obstruction than during a central one [less ▲]

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See detailMechanical properties of highly porous PDLLA/Bioglass (R) composite foams as scaffolds for bone tissue engineering
Blaker, Jonny J.; Maquet, Véronique; Jérôme, Robert ULg et al

in Acta Biomaterialia (2005), 1(6), 643-652

This study developed highly porous degradable composites as potential scaffolds for bone tissue engineering. These scaffolds consisted of poly-d,l-lactic acid filled with 2 and 15 vol.% of 45S5 Bioglass® ... [more ▼]

This study developed highly porous degradable composites as potential scaffolds for bone tissue engineering. These scaffolds consisted of poly-d,l-lactic acid filled with 2 and 15 vol.% of 45S5 Bioglass® particles and were produced via thermally induced solid–liquid phase separation and subsequent solvent sublimation. The scaffolds had a bimodal and anisotropic pore structure, with tubular macro-pores of 100 μm in diameter, and with interconnected micro-pores of 10–50 μm in diameter. Quasi-static and thermal dynamic mechanical analysis carried out in compression along with thermogravimetric analysis was used to investigate the effect of Bioglass® on the properties of the foams. Quasi-static compression testing demonstrated mechanical anisotropy concomitant with the direction of the macro-pores. An analytical modelling approach was applied, which demonstrated that the presence of Bioglass® did not significantly alter the porous architecture of these foams and reflected the mechanical anisotropy which was congruent with the scanning electron microscopy investigation. This study found that the Ishai–Cohen and Gibson–Ashby models can be combined to predict the compressive modulus of the composite foams. The modulus and density of these complex foams are related by a power-law function with an exponent between 2 and 3. [less ▲]

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See detailMechanical properties of spread films from Acacia gums.
Blecker, Christophe ULg

Poster (2000, June)

Detailed reference viewed: 6 (3 ULg)