La lombalgie est une douleur de la région lombaire du rachis. Un des moyens communément utilisés pour soulager cette douleur est le port d’orthèses lombaires. Bien que l’efficacité de ces orthèses soit démontrée, leur mode d’action reste mal connu. L’objectif de ce projet est d’analyser ce mode d’action dans le cas de ceintures de soutien lombaire.En lien avec des médecins et un industriel, trois approches ont été mises en œuvre. Premièrement, une approche expérimentale a permis de déterminer les propriétés mécaniques des ceintures de soutien lombaire et d’évaluer la pression appliquée suivant ces propriétés. Secondairement, la pression appliquée par les ceintures a été mesurée par une approche clinique. Cette pression a été liée à la diminution de la douleur engendrée par les ceintures, au bien-être ressenti, à la modification de la posture et à la déformation de la ceinture. Troisièmement, une approche numérique a servi à montrer les paramètres influents sur le soulagement de la douleur.Un des modes d’action des ceintures de soutien lombaire, mis en évidence dans ce projet, est la pression appliquée sur le tronc qui engendre une variation des pressions abdominale et intradiscale, ainsi qu’une modification de la posture. La pression appliquée dépend, entre autres, des caractéristiques mécaniques des ceintures. Les résultats mettent en évidence l’importance de maitriser cette pression appliquée ainsi que la spécificité du patient sur les effets mécaniques des ceintures.Les différentes approches sont complémentaires ; elles sont des moyens de caractérisation des orthèses qui pourraient être utilisés pour d’autres orthèses et également aider au développement de produits. / Low back pain is a pain felt in the lumbar region of the spine. Lumbar orthotics might be used to relieve this pain. Efficacy of lumbar orthotics was proved, but mechanical effects remain unclear. Aim of this project if to analyze these mechanical effects for lumbar belts, a specific lumbar orthotic.In relation with clinicians and manufacturer, three different approaches were developed. First, experimental approach permits to determine mechanical properties of lumbar belts and to evaluate applied pressure related to these mechanical properties. Second, applied pressure by lumbar belts was measured using a clinical approach. This pressure has been related to the decrease in pain, to the wellbeing felt, to the modification of posture and to the lumbar belts strain. Third, numerical approach was used to demonstrate the influential parameters on pain relief.One of mechanical effects of lumbar belts, highlighted in this project, is the pressure applied on the trunk which causes change in abdominal and intradiscal pressure and posture. The applied pressure depends on the mechanical properties of the belts. Results demonstrate the importance of mastering the applied pressure and the specificity of the patient on the mechanical effects of belts. The different approaches are complementary; they are orthotics characterization tools that could be used for others orthotics and also helps in the development of new products.

The Kalahari Goldridge mine is located within the Archaean Kraaipan Greenstone Belt about 60 km SW of Mafikeng in the Northwestern Province, South Africa. Several gold deposits are located within approximately north - south-striking banded iron-formation (BIF). Current opencast mining operations are focused on the largest of these (D Zone). The orebody is stratabound and hosted primarily in the BIF, which consists of alternating chert and magnetite-chloritestilpnomelane-sulphide-carbonate bands ranging from mm to cm scale. The ore body varies in thickness from 15 to 45 m along a strike length of about 1.5 km. The BlF is sandwiched between a sericite-carbonate-chlorite schist at the immediate footwall and carbonaceous meta-pelites in the hanging-wall. Further west in the footwall, the schists are underlain by mafic meta-volcanic amphibolite. Overlying the hanging-wall carbonaceous metapeiites are schist units and meta-greywackes that become increasingly conglomeratic up the stratigraphy. Stilpnomelane-, chlorite- and minnesotaite-bearing assemblages in the BlFs indicate metamorphic temperatures of 300 - 450°C and pressures of less than 5 kbars. The BIF generally strikes approximately 3400 and dips from 60 to 75°E. Brittle-ductile deformation is evidenced by small-scale isoclinal folds, brecciation, extension fractures and boudinaging of cherty BIF units. Fold axial planes are sub-parallel to the foliation orientation with sub-vertical plunges parallel to prominent rodding and mineral lineation in the footwall. Gold mineralization at the Kalahari Goldridge deposit is associated with two generations of subhorizontal quartz-carbonate veins dips approximately 20 to 40°W. The first generation consists of ladder vein sets (Group lIA) preferentially developed in Fe-rich meso bands, whilst the second generation consists of large quartz-carbonate veins (Group lIB), which crosscut the entire ore body extending into the footwall and hanging-wall in places. Major structures that control the ore body are related to meso-scale isoclinal folds with fold axes subparallel to mineral elongation lineations, which plunge approximately 067°E. These linear structures form orthogonal orientation with the plane of the mineralized shallowdipping veins indicating stretching and development of fluid - focusing conduits. A second-order controlling feature corresponds to the intersection of the mineralized veins and foliation planes of host rock, plunging approximately 008°N and trending 341°. G0ld is closely associated with sulphides, mainly pyrite and pyrrhotite and to a lesser extent with bismuth tellurides, and carbonate gangue. The ore fluid responsible for the gold deposition is in the C-O-H system with increased CH₄ contents attributed to localized hydrolysis reaction between interbedded carbonaceous sediment and ore fluid. The fluid is characterized by significant C0₂ contents and low salinities below 7.0 wt % NaCl equivalent (averages of 3.5 and 3.0 wt % NaCl equivalent for the first and second episodes of the mineralization respectively) . Calculated values of f0₂. ranging from 10⁻²⁹·⁹⁸ to 10⁻³²·⁹⁶ bars, bracket the C0₂-CH₄ and pyrite-pyrrhotite-magnetite buffer boundaries and reveal the reducing nature of the ore fluid at deposition. Calculated total sulphur content in the ore fluid (mΣs), ranges from 0.011 to 0.018M and is consistent with the range (10⁻³·⁵ to 10⁻¹M) reported for subamphibolite facies ore fluids. The close association of sulphides with the Au and nature of the fluid also give credence that the Au was carried in solution by the Au(HS)₂ - complex. Extensive epigenetic replacement of magnetite and chlorite in BIF and other meta-pelitic sediments in the deposit by sulphides and carbonates, both on meso scopic and microscopic scales gives evidence of an interaction by a CO₂- and H₂S-bearing fluid with the Fe-rich host rocks in the deposit. This facilitated Au precipitation due to changes in the physico-chemical conditions of the ore fluid such as a decrease in the mΣs and pH leading to the destabilization of the reduced sulphur complexes. Local gradients in f0₂ may account for gold precipitation in places within carbonaceous sediments. The fineness of the gold grams (1000*Au/(Au + Ag) ranges from 823 to 921. This compares favourably with the fineness reported for some Archaean BIFhosced deposits (851 - 970). Mass balance transfer calculations indicate that major chemical changes associated with the hydrothermal alteration of BIF include enrichment of Au, Ag, Bi, Te, volatiles (S and CO₂), MgO, Ba, K and Rb but significant depletion of SiO₂ and minor losses of Fe₂O₃. In addition, anomalous enrichment of Sc (average, 1247%) suggests its possible use as an exploration tool in the ferruginous sediments in the Kraaipan greenstone terrane. Evidence from light stable isotopes and fluid inclusions suggests that the mineralized veins crystallized from a single homogeneous fluid source during the two episodes of mineralization under the similar physicochemical conditions. Deposition occurred at temperatures rangmg from 350 to 400°C and fluid pressures ranging from 0.7 to 2.0kbars. Stable isotope constraints indicate the following range for the hydrothermal fluid; θ¹⁸H₂O = 6.65 to 10.48%0, 8¹³CΣc = -6.0 to -8.0 %0 and 8³⁴SΣs = + 1.69 to + 4.0%0 . These data do not offer conclusive evidence for the source of fluid associated with the mineralization at the Kalahari Goldridge deposit as they overlap the range prescribed for fluid derived from devolatization of deep-seated volcano-sedimentary piles near the brittle-ductile transition in greenstone belts during prograde metamorphism, and magmatic hydrothermal fluids. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

The emergence of small and affordable satellites has led to rapid growth in the number of launched satellites over the past two decades. To save costs, small satellites often use mass-produced electronic components not explicitly designed for the radiation environment of space, which reduces reliability and makes them unsuitable for higher orbits. Improved radiation protection would enable small satellites to operate in high radiation environments and increase their reliability. This work investigates how small satellite electronics can be protected against the high radiation environment of geostationary transfer orbit on the example of the Foresail-2mission. Foresail-2 is a planned 6U CubeSat mission to the Earth radiation belts and is intended to use consumer-grade electronics components. In this harsh environment, most semiconductor devices require radiation shielding. The Space EnvironmentInformation System of the European Space Agency was used to analyse expected particle spectra along the planned orbit through the radiation belts. These particle spectra were then used in Monte-Carlo simulations based on the Geant4 particle transport toolkit to simulate the performance of different shielding configurations. Several thousand multilayer shielding configurations were simulated to optimise the material composition and layer structure of multilayer shielding. The best multilayer configurations against the combined proton and electron spectra of the Earth’s radiation belts use materials with low proton numbers on top of materials with high proton numbers and can significantly outperform conventional aluminium shielding. However, the usage of alternative materials might introduce significant overhead in the design and manufacturing of the satellite structure. Additionally, the influence of satellite structure geometry and openings in the shield was analysed. Even a 1 cm2 opening in the shield can increase the total ionising dose received by electronic components over a mission lifetime by more than an order of magnitude. In conclusion, the work recommends an aluminium body of 6 mm or equivalent multilayer shielding for the Foresail-2 mission to reduce the radiation level to a tolerable level for consumer-grade electronics, while openings in the satellite body should be avoided or covered up with additional shielding. / FORESAIL

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents a comprehensive study of the effects of material, geometric and operational parameters on flat belt-drives steady-state belt stresses, belt slip, and belt-drive efficiency. The belt stresses include: belt rubber shear, normal, axial and lateral stresses; reinforcements tension force; and tangential and normal belt-pulley contact stresses. Belt slip is measured using the driven over driver pulleys’ angular velocity ratio. Each parameter was varied over a range to understand its impact on the steady-state belt-drive response. The material parameters studied are belt axial stiffness and damping, belt bending stiffness and damping, and belt-pulley friction coefficient. The geometric parameters studied are pulley center distance, pulleys diameter ratio, and belt thickness. The operational parameters studied are the driver pulley angular velocity and the driven pulley opposing torque (load). A high-fidelity flexible multibody dynamics parametric model of a two-pulley belt-drive system was created using a commercial multibody dynamics code. In the model the belt’s rubber matrix is represented using three-dimensional brick elements and the belt’s reinforcements are represented using one dimensional beam elements at the top surface of the belt. An asperity-based Coulomb friction model is used for the friction forces between the pulley and belt. The pulleys are modeled as rigid bodies with a cylindrical contact surface. The equations of motion are integrated using an explicit solution procedure. Unlike prior models which use one-dimensional truss or beam elements for the belt, the present model uses a three-dimensional belt model which introduces the effect of the thickness of the belt rubber matrix (modeled using brick elements). This enables a more accurate prediction of the belt stresses and slip than prior models. This thesis resolves in more details the complex stick-slip friction behavior of an axially flexible belt coupled with the shear effects of a flexible rubber cushion and at the same time shows the effect of the main system parameters on this stick-slip behavior. Some of the important conclusions of the thesis include: (1) the driver pulley has two distinct contact zones - a negative traction zone and a positive traction zone - while only one traction zone is present over the driven pulley; (2) the width of the negative traction zone on the driver pulley increases with the belt-pulley coefficient of friction and decreases with the belt axial stiffness; (3) the maximum belt tension and normal contact stress occur on the driver pulley and increase with the belt thickness, belt axial stiffness, and coefficient of friction; (4) belt-drive energy efficiency increases with the belt axial stiffness, and decreases with belt thickness, belt bending damping, belt operating speed, and operating torque load. The belt-drive modeling methodology presented in this thesis which enables accurate prediction of the belt stresses and slip can in turn be used to more accurately predict the fatigue life, wear life, and energy efficiency of belt-drives.

Die moderne Lebensmittel- und Verpackungsindustrie stellt hohe Anforderungen an den Umgang mit den Produkten und die Prozesshygiene. Transportbänder sind gängige Werkzeuge in der Produktion und unterliegen je nach Einsatzart den verschiedensten Anforderungen. Atmosphärische Plasmen stellen eine innovative Technologie zur gezielten Modifizierung von Oberflächen dar. Die Behandlung von Transportbändern mit atmosphärischen Plasmen verspricht eine Optimierung der Reinigungszyklen in der Lebensmittelindustrie und eine Verbesserung der Hygiene beim Transport von Lebensmitteln auf Transportbändern allgemein. [Zusammenfassung]

The aim of this study is concentrated on the experimental investigation of wear resistance of rubber powder modified rubber blends. Styrene-Butadiene-Rubber (SBR) blends applied for conveying belt top covers have been modified by ground rubber (rubber powder) based on SBR. We theoretically described the rubber wear mechanism due to loading conditions occurring at conveyor belts in the field, to simulate wear behavior of top cover rubber materials. An own developed testing equipment based on gravimetric determination of mass loss of rubber test specimen was used investigating dynamic wear with respect to fracture properties of top cover materials. Furthermore we investigated fatigue crack growth (FCG) data over a broad range of tearing energy by Tear Analyzer to characterize crack propagation behavior of rubber powder modified rubber blends. Thus, we demonstrate the influence of rubber powder on resistance against occurrence of fracture as well as dynamic wear as a function of the rubber powder content in rubber blends applied for conveying belt top covers.

No description available.

The type and duration of observation and monitoring of mother and fetus after abdominal trauma are dependent on gestational age and severity of trauma. Fetal monitoring is usually not required when the fetus is not viable; the primary consideration is the safety of the mother. When the fetus is viable, 24-hour inpatient fetal monitoring is indicated in cases of major trauma, even when no symptoms of injury are obvious.

Les applications entrainées par des moteurs asynchrones consomment à elles seules la majorité de l’énergie électrique utilisée dans le secteur industriel. Des défauts, majoritairement d’origine mécanique, sont susceptibles de se développer au cours du fonctionnement de ces systèmes et rendent nécessaires la mise en place d’une maintenance souvent onéreuse. Afin de réduire ces coûts et d’optimiser la disponibilité des matériels, des méthodes de diagnostic peuvent être développées afin de détecter au plus tôt l’apparition d’un défaut. Cependant, la fiabilité de ces algorithmes et l’automatisation du diagnostic sont complexifiées par la diversité des systèmes alimentés par les variateurs de vitesse industriels ainsi que par le changement de leur point de fonctionnement. Afin de répondre à ces problématiques, un protocole de diagnostic permettant de réaliser une détection sensible et robuste des défaillances mécaniques est développé dans ce travail. Cette méthode consiste à segmenter le plan couple-vitesse du moteur surveillé et à réaliser des références statistiques caractérisant son fonctionnement sain sur chacune des zones de fonctionnement. Des indicateurs de défaut peuvent ensuite être définis statistiquement afin de quantifier l’écart du système vis-à-vis de son comportement sain. Ces indicateurs sont ainsi indépendants du système surveillé et de son point de fonctionnement. Les principales applications ciblées par ce protocole sont les systèmes de compression, de pompage et de ventilation qui représentent une part importante de l’énergie électrique consommée dans le secteur industriel. Le protocole de diagnostic développé dans cette étude est validé expérimentalement dans le cadre de la détection de différentes niveaux de déséquilibre mécanique mais également pour la surveillance d’un système de transmission de type poulies-courroies. De plus, les campagnes expérimentales sont effectuées sur plusieurs systèmes électromécaniques dont les propriétés sont foncièrement différentes afin de valider les performances de normalisation de ce protocole. / Systems driven by induction motors consume most of the industrial electric supply. Mechanical faults may develop over time and disrupt their proper functioning, resulting in high maintenance expenditure. In order to reduce these costs and to improve machines availability, diagnosis methods can be developped to perform the early detection of incipient faults. However, the variety of industrial applications driven by induction motors complicates the automation of fault detection. To resolve these issues, a sensitive and robust diagnosis protocol has been developed in two stages. First, the torque-speed plane of the monitored motor is segmented in different functioning areas. Then, a statistical reference is achieved on each operating zone in order to characterize the healthy working of the system. Statistic-based indicators may then quantify the system deviation from its healthy behaviour. These indicators are therefore independent of the monitored system and of its functioning point. The applications targeted by this study are fans, pumps and compressors which are widely used in industrial processes. This diagnosis protocol is experimentally validated on the detection of several levels of mechanical unbalance and for the monitoring of V-belts drive health state. Moreover, test campaigns are achieved on varied electromechanical systems in order to validate the normalization performances of the developed protocol.

Cette thèse porte sur les interactions entre les déformations halocinétiques locales au sein des mini-bassins salifères et les déformations régionales compressives. L’étude s’appuie sur une analyse structurale multi-échelle détaillée d’une province à mini-bassins se développant dans le bassin d’avant pays de Sivas (Turquie). Une analyse de terrain approfondie, associée à une étude de données de subsurface, permet de proposer une révision des cartes géologiques ainsi qu’une évolution tectonosédimentaire identifiant les déformations liées à la tectonique salifère et celles liées à la propagation de la ceinture de plis et de chevauchements dans l’avant-pays. A partir de l’Eocène supérieur, le fluage del’évaporite autochtone, initié et entretenu par le chargement sédimentaire différentiel ainsi que par la déformation compressive, permet la formation d’une première génération de mini-bassins. Ces minibassins, constitués par une formation continentale Oligocène, vont être recouverts par une nappe d’évaporite allochtone accueillant une seconde génération de mini-bassins constitués de formations continentales et marines Oligo-Miocène. L’initiation du domaine de mini-bassins secondaires est caractérisée par une distribution polygonale du réseau de diapirs et de murs d’évaporites. Ces mini-bassins enregistrent localement les effets de la tectonique salifère par le développement d’une grande variété de structures halocinétiques à différentes échelles telles que les séquences halocinétiques unitaires (crochet et éventail), séquences composites (tabulaire ou fuseau) et megaflaps. Une série de modélisation analogique préliminaire amontré que ces structures peuvent se développer avec ou sans l’application d’une compression aux limites. De plus, les analogies géométriques entre les mini-bassins de Sivas et les provinces salifères connues suggèrent que la dynamique de formation de ces mini-bassins est au premier ordre contrôlée par le chargement sédimentaire différentiel, découplé partiellement de la compression régionale. Néanmoins, l’analyse du réseau de fractures et de l’endommagement matriciel souligne l’enregistrement précoce de la déformation compressive régionale lors de l’initiation des mini-bassins.L’influence du raccourcissement sur la structuration de la province à mini-bassins s’exprime de manière croissante par l’écrasement des corps salifères permettant : (i) le développement de dépocentres linéaires préférentiellement perpendiculaire à la direction de raccourcissement, (ii) l’émergence de corps allochtones d’évaporites en surface, ainsi que (iii) la rotation et translation des mini-bassins. Cette province à mini-bassins génère une discontinuité dans la propagation et l’accommodation de la déformation compressive : la déformation compressive est accommodée auniveau du réseau polygonal de murs d’évaporites formant des structures multidirectionnelles. De plus, cette concentration de la déformation par écrasement des structures salifères entraine la remobilisation des évaporites vers l’avant-pays générant alors un nouveau système salifère. / This doctoral work studies the interaction between withdrawal of minibasins and regional shortening during evolution of a foreland fold-and-thrust belt. This is achieved by a multiscale structural analysis of the Sivas Basin (Turkey). Extensive field work and regional seismic lines interpretations helped to build a new and detailed geologic map of the central Sivas Basin and to provide a new tectonosedimentary framework highlighting the influence of salt tectonics and the regional shortening, starting in the Late Eocene by the autochthonous evaporite deposition. This level is remobilized by the northward migrating sedimentary load, shortening and tilting of the basin southern margin during propagation of the foreland fold-and-thrust belt. Evaporite flow is recorded by the withdrawal of a primary generation of continental Oligocene minibasins which are then covered by an evaporite canopy. The canopy extending northward allows the development of second generation of continental to shallow marine mini-basins from Oligocene to Middle Miocene. Secondary minibasins initiation in the central part of the Basin, is characterized by sub-circular minibasins surrounded by polygonal diapirs and walls. Flanking these minibasins, a large variety of halokinetic structures is described: halokinetic sequences (hooks and wedges), composite halokinetic sequences and megaflaps. Preliminary sand-box modeling study suggests the development of thesehalokinetic structures both with and without shortening. Furthermore, minibasins geometries are closely similar to those imaged or mapped in other salt provinces suggesting that mini-basin withdrew is first control by sedimentary load, probably due to decoupling by the salt. However, the fractures and anisotropy of magnetic susceptibility analyses suggests the record of shortening since the minibasins initiation. The increase influence of regional shortening on the minibasins domain is expressed by salt walls and diapirs squeezing inducing: (i) the development of linear mini-basins perpendicular to the shortening direction, (ii) salt sheet emplacement and (iii) the translation/rotation of minibasins. The minibasins province produces a discontinuity for the fold-and-thrust belt propagation. Indeed, the minibasins province accommodates the shortening deformation along the polygonal network of salt walls and diapirs forming multidirectional structures. Furthermore, the regional shortening accommodation by salt structures squeezing produce an evaporitic remobilization and migration of a salt canopy toward the foreland basin. / Bu doktora tezi/çalışması, bir önülke kıvrım ve bindirme kuşağının evrimi sırasında minihavzaların çekilmesi ve bölgesel kısalma arasındaki etkileşimi konu edinir. Çoklu ölçekteki bu yapısal analiz Sivas Havzası (Türkiye) ölçeğinde gerçekleştirilmiştir. Kapsamlı saha çalışması ve bölgesel olarak sismik kesitlerden ortaya çıkarılan yorumlamalar, Sivas Havzası’nın orta kesiminde detaylı bir jeolojik haritalama yapımına yardımcı olmuş ve otokton evaporit depolanmasının başladığı Geç Eosen’den başlayarak havza için tuz tektoniği ve bölgesel kısalmanın etkisindeki yeni bir tektono-sedimanter çatının ortaya çıkarılmasına neden olmuştur. Söz konusu seviye, önülke kıvrım ve bindirme kuşağının ilerlemesisüresince kuzeye doğru sedimanter dolgunun göçüyle birlikte havzanın güney kenarında kısalıma uğrayarak ve eğim kazanarak remobilize olmuştur. Evaporit akışı, kıtasal Oligosen minihavzalarının ilksel olarak oluşumundan sonra çekilmesine bağlı olarak gözlenmiş ve sonrasında evaporit yaygılarıyla örtülmüştür. Kuzeye kadar uzanan bu yaygı, Oligosen-Orta Miyosen arasında kıtasaldan sonra sığ denizel tipteki ikincil minihavzaların gelişimine de neden olmuştur.Havzanın orta kesimindeki ikincil minihavza başlangıcı, poligonal diyapir ve duvarlar tarafından çevrelenen dairesel minihavzalarla karakterize olur. Bu minihavzaların kanatlarında halokinetik yapılar tanımlanmıştır. Kanca (hook) ve kama (wedge) tiplerde olmak üzere halokinetik seriler, kompozit halokinetik seriler ve megaflaplar bu yapılar arasında sayılabilir. Çalışmanın başlangıcında yapılan kum kutusu model deneyi, bu halokinetik yapıların kısalmayla veya kısalma olmaksızın geliştiğini göstermiştir. Buna ek olarak minihavzaların geometrisi, muhtemelen tuzun ayrışmasından dolayı tortul yükün ilkkontrolünden dolayı çekilen diğer tuz bölgelerinde önerilen haritalanmış minihavzalara benzerdir. Bununla birlikte kırık ve manyetik suseptibilite analizleri, minihavzaların başlangıcından itibaren kısalmanın kayıt edilebilmesi hakkında fikir vermektedir. Minihavza bölgelerindeki bölgesel kısalımın artışı, tuz duvarları ve diyapirlerin sıkışmasıyla birlikte(i) kısalma yönüne dik durumdaki çizgisel minihavzaların gelişimi, (ii) tuz örtülerinin yerleşimi ve (iii) minihavzaların yer değiştirmesi veya dönmesiyle açıklanır. Minihavzalar bölgesi, kıvrım ve bindirme kuşağının gelişimi için bir süreksizlik üretir. Aslında, minihavzalar birçok yönde yapılar oluşturarak tuz duvarları ve diyapirlerin polygonal şekildeki yerleşimi boyunca kısalma deformasyonuna eşlik eder. Üstelik, tuz yapılarının eşlik ettiği bölgesel kısalma önülke havzalarına doğru evaporitik bir göçe de neden olmaktadır.