Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

OBJECTIF DU TRAVAIL


Le but de ce travail est d’améliorer la connaissance du comportement biomécanique du membre pelvien du chien, en étudiant le rôle de la fibula dans la résistance en torsion de celui-ci. L’os, de par sa structure tubulaire, se révèle en effet particulièrement susceptible aux contraintes de cisaillement. De plus, le rôle de la fibula dans le support de contraintes en torsion et dans la guérison de fractures du tibia à fibula intacte a déjà été démontré lors d’expérimentations semblables chez l’homme et le rat. Un abord expérimental a été choisi et est intéressant de par l’opportunité d’objectiver et de calculer les contraintes maximales supportées. Cette connaissance est fondamentale notamment en orthopédie, en permettant au chirurgien orthopédiste vétérinaire de mieux comprendre la répartition des forces dans la jambe du chien, la résistance de chaque os et ainsi d’affiner ses choix thérapeutiques lorsqu’il est confronté à des fractures. En accédant à un répertoire de données théoriques plus complet, il pourra en effet choisir de manière optimale non seulement quelle approche, conservatrice ou chirurgicale, sera la plus indiquée, mais également d’estimer les dimensions du matériel d’ostéosynthèse les plus favorables à une récupération et de préciser le pronostic de celle-ci. 


RÉSUMÉ

Ce travail abordera tout d’abord les aspects théoriques généraux les plus importants en biomécanique et présentera brièvement la physiopathologie et les principes de réparation de fractures tibiales. Il présentera également une étude réalisée chez le rat qui prouve le rôle de la fibula dans la rigidité en torsion du membre pelvien de cette espèce et son rôle dans la guérison des fractures du tibia à fibula intacte. Enfin, la seconde partie de ce travail sera consacrée à l’approche expérimentale. En 2006, Tambyah et Pereira ont démontré que la présence d’une fibula intacte augmentait la rigidité en torsion de la jambe humaine. Cette expérience en a inspiré une deuxième, en médecine vétérinaire. Ainsi, les membres pelviens de 13 chiens ont été récupérés et disséqués pour ne conserver que le tibia, la fibula et les tissus mous qui les entourent. 6 de ces 13 chiens ont ensuite subi une ostéotomie fibulaire proximale. Tous les membres ont ensuite été testés en rotation externe. La déformation unitaire, la contrainte maximale imposée en torsion, la déformation angulaire maximale et la résistance en torsion ne présentaient aucune différence significative entre les 2 groupes. Ainsi, les méthodes utilisées et les résultats obtenus seront discutés. Un point important de ce travail sera l’étude des limites et des perspectives apportées par cette étude, notamment afin d’affiner les expériences futures. L’absence de prise en compte des propriétés de visco-élasticité et des contraintes exercées par les muscles, in vivo, représentent les principales limites de cette expérience.

fracture --- fibula --- torsion --- raideur --- Sciences du vivant > Médecine vétérinaire & santé animale

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

"Manifolds with fibered cusps are a class of complete non-compact Riemannian manifolds including many examples of locally symmetric spaces of rank one. We study the spectrum of the Hodge Laplacian with coefficients in a flat bundle on a closed manifold undergoing degeneration to a manifold with fibered cusps. We obtain precise asymptotics for the resolvent, the heat kernel, and the determinant of the Laplacian. Using these asymptotics we obtain a topological description of the analytic torsion on a manifold with fibered cusps in terms of the R-torsion of the underlying manifold with boundary"--

Riemannian manifolds. --- Symmetric spaces. --- Torsion theory (Algebra) --- Resolvents (Mathematics) --- Heat equation. --- Kernel functions. --- Surfaces, Algebraic --- Surgery (Topology) --- Global analysis, analysis on manifolds -- Partial differential equations on manifolds; differential operators -- Elliptic equations on manifolds, general theory. --- Global analysis, analysis on manifolds-- Partial differential equations on manifolds; differential operators -- Heat and other parabolic equation methods for PDEs on manifolds. --- Global analysis, analysis on manifolds -- Partial differential equations on manifolds; differential operators -- Spectral problems; spectral geometry; scattering theory on manifolds. --- Global analysis, analysis on manifolds -- Partial differential equations on manifolds; differential operators -- Determinants and determinant bundles, analytic torsion. --- Algebraic topology -- Homology and cohomology theories -- Homology with local coefficients, equivariant cohomology. --- Algebraic topology -- Homology and cohomology theories -- Intersection homology and cohomology in algebraic topology. --- Degenerations.

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

Severe plastic deformation (SPD) is a very attractive research field for metallic materials because it provides new possibilities for manufacturing nanostructured materials in large quantities and allows microstructural design on different hierarchical levels. The papers included in this issue address the following topics: novel SPD processes as well as recent advancements in established processing methods, microstructure evolution and grain refinement in single- and multi-phase alloys as well as composites, strategies to enhance the microstructure stability at elevated temperatures, mechanically driven phase transformations, surface nanostructuring, gradient and multilayered materials, and mechanical and physical properties of SPD-processed materials.

History of engineering & technology --- Mg-3.7Al-1.8Ca-0.4Mn alloy --- Al2Ca phase --- equal channel angular pressing --- refinement --- mechanical properties --- aluminium copper-clad rod --- hardness --- effective electrical conductivity --- severe plastic deformation --- Mg-9Li duplex alloy --- ECAP --- rolling --- high strength --- microstructure --- high pressure torsion extrusion --- gradient structure --- hardness distribution --- tensile properties --- copper --- high pressure torsion --- microstructural characterization --- magnetic properties --- hysteresis --- magneto-resistance --- β titanium alloys --- α phase precipitation --- phase composition --- high energy synchrotron X-ray diffraction --- metastable β-Ti alloys --- powder metallurgy --- cryogenic milling --- spark plasma sintering --- surface mechanical attrition treatment (SMAT) --- ultrasonic shot peening (USP) --- functionally graded materials (FGM) --- titanium niobium alloys --- titanium molybdenum alloys --- human mesenchymal stem cells culture --- cell adhesion --- cell proliferation --- magnesium --- equal-channel angular pressing --- deformation tests --- texture --- schmid factor --- cryogenic temperature --- 304L austenitic stainless steel --- rotating–bending fatigue --- tension–compression fatigue --- TiNi alloy --- thermal cycling --- ultrafine-grained structure --- microstructural and mechanical stability --- Ti–Fe --- high-pressure torsion --- high-temperature XRD --- differential scanning calorimetry --- phase diagram --- CalPhaD --- Mg alloy --- severe plastic deformation (SPD) --- intermetallic precipitates --- vacancy agglomerates --- corrosion --- n/a --- rotating-bending fatigue --- tension-compression fatigue --- Ti-Fe

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

Severe plastic deformation (SPD) is a very attractive research field for metallic materials because it provides new possibilities for manufacturing nanostructured materials in large quantities and allows microstructural design on different hierarchical levels. The papers included in this issue address the following topics: novel SPD processes as well as recent advancements in established processing methods, microstructure evolution and grain refinement in single- and multi-phase alloys as well as composites, strategies to enhance the microstructure stability at elevated temperatures, mechanically driven phase transformations, surface nanostructuring, gradient and multilayered materials, and mechanical and physical properties of SPD-processed materials.

History of engineering & technology --- Mg-3.7Al-1.8Ca-0.4Mn alloy --- Al2Ca phase --- equal channel angular pressing --- refinement --- mechanical properties --- aluminium copper-clad rod --- hardness --- effective electrical conductivity --- severe plastic deformation --- Mg-9Li duplex alloy --- ECAP --- rolling --- high strength --- microstructure --- high pressure torsion extrusion --- gradient structure --- hardness distribution --- tensile properties --- copper --- high pressure torsion --- microstructural characterization --- magnetic properties --- hysteresis --- magneto-resistance --- β titanium alloys --- α phase precipitation --- phase composition --- high energy synchrotron X-ray diffraction --- metastable β-Ti alloys --- powder metallurgy --- cryogenic milling --- spark plasma sintering --- surface mechanical attrition treatment (SMAT) --- ultrasonic shot peening (USP) --- functionally graded materials (FGM) --- titanium niobium alloys --- titanium molybdenum alloys --- human mesenchymal stem cells culture --- cell adhesion --- cell proliferation --- magnesium --- equal-channel angular pressing --- deformation tests --- texture --- schmid factor --- cryogenic temperature --- 304L austenitic stainless steel --- rotating-bending fatigue --- tension-compression fatigue --- TiNi alloy --- thermal cycling --- ultrafine-grained structure --- microstructural and mechanical stability --- Ti-Fe --- high-pressure torsion --- high-temperature XRD --- differential scanning calorimetry --- phase diagram --- CalPhaD --- Mg alloy --- severe plastic deformation (SPD) --- intermetallic precipitates --- vacancy agglomerates --- corrosion

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

The Special Issue “Recent Advancements in Metallic Glasses” presents ten original papers, considering both scientific and application issues related to metallic glasses. The papers are devoted to general consideration of the formation and defects of the glassy structure, defect evolution due to heat treatment, deformation behavior upon compression and high-pressure torsion, amorphous-crystalline transformation, hydrogenation behavior, and biomedical applications.

metallic glasses --- defects --- structural relaxation --- heat effects --- shear elasticity --- interstitialcy theory --- mechanical spectroscopy --- mixing enthalpy --- Kohlrausch–Williams–Watts equation --- structural heterogeneity --- metallic glass --- twin roll casting --- GFA --- MicroCT --- hydrogen --- indentation --- pop-in --- plasticity --- nanoglasses --- structure evolution --- properties --- bulk metallic glass --- shear band --- dislocation theory --- scanning white light interferometry --- high-pressure torsion --- severe plastic deformation --- transmitting electron microscopy --- X-ray diffraction --- differential scanning calorimetry --- free volume --- shear modulus --- composite --- amorphous alloy --- nanolaminate --- hardness --- crack resistance --- nanostructure --- HPT deformation --- metastable phases --- n/a --- Kohlrausch-Williams-Watts equation