A project report sUbmitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Sandtoh, 1995. / Amplitude modulation, is the oldest modulation technique used for voice communication.It is the simplest and cheapest way to modulate and demodulate voice, and as a result, it did not lose much popularity in spits of the development of other, more efficient modulation technique. This project offers a new approach for AM demodulation. The two sidebands are separated and divided into many su-bands. The signals with the lowest noise level are solected and thier levels are individually adjusted according to signal conditions. The result is reduction of over 35 dB in continuous interference and about 15 dB in whit noise level. The new detector and about out-performs the conventional detectors in all aspects and can be used in applications where top performance is required and where mone is no object.

No description available.

Fractures in carbonate strata are often associated with dissolution features such as karst cavities along the fracture plane. Integration of full resolution 3D GPR data and outcrop observation allows the visualization and quantification of fractures and karst cavites in three dimensions. Three 3D GPR cubes were acquired in the Solvay quarry, Provence region, SE France. The quarry exposes an intensly fractured and karstified shallow-water Barremian carbonates with matrix porosity less than 1.8%. The quarry walls provide the 2D information of the fractures (location, type, orientation, dip, length, aperture, spacing and stratigraphic position) and the karst (location, size, shape, stratigraphic position and relationship with fractures), that were documented using 1D scan line measurement. Several deformation features are observed in the quarry, dominated by meter-scale joints and tension gashes, and also minor faults, burial and tectonic-related stylolites. Three major fracture orientations (E-W, NW-SE and N-S) were found in the quarry with a non-uniform distribution influenced by structural position relative to major structural features (eg: large fractures (>10m) and faults). Interpretation of 3D GPR data reveals one major fracture orientation (NE-SW) that was not observed in the outcrop because it is oriented parallel with the quarry wall. Besides fractures, karst were also documented in outcrop as well as in 3D GPR data. Combination between 3D GPR and outcrop observation show that in the Solvay quarry karst occur along fracture plane and preferentially at fracture intersections. The karst are decimeter to meter-size karst which are below the resolution of 3D seismic reflection. Quantification of karst in the quarry show that karst size-frequency distribution follows power-law distribution, where small karst is more common and large karst is less common. The volume of karst in the quarry is up to 3.8% of the total rock volume. The power-law scaling relationship and the quantification of the sub-seismic karst volume will help predicting karst arrays in wide range of sizes in subsurface reservoirs, where visualization of karst is restricted to the resolution of 3D seismic data.

L’amplitude articulaire maximale (AAM) ou flexibilité, est un paramètre fonctionnel fréquemment utilisé dans la pratique clinique, sportive et au sein des protocoles de recherche pour estimer la longueur maximale de l'unité muscle-tendon (UMT). Il a longtemps été considéré que l’AAM est limitée par la tension développée par les UMTs étirées pendant le mouvement articulaire (mechanical theory). Cependant, un nombre important de recherches expérimentales suggèrent que l’étirement peut induire une augmentation de l’AAM en absence d'adaptations mécaniques significatives dans l’UTM (sensory-based theory). Récemment, les structures non-musculaires telles que les nerfs périphériques ont été suggérées comme facteurs limitant l'amplitude d'étirement. Cette thèse vise à mieux comprendre le rôle mécanique des tissus musculaires et nonmusculaires qui peuvent influencer la limitation de l’AAM in-vivo. En utilisant la technique d’élastographie permettant d’évaluer la raideur passive des muscles et des nerfs individuellement, quatre études ont été réalisées pour : déterminer si l’étirement des structures musculaires et non musculaires limite l’AAM et si les propriétés mécaniques des tissus étirés s'adaptent à l’étirement aigu ou chronique. Les résultats ont montré que l’AAM peut être limitée par des structures musculaires ou non-musculaires. Le positionnement des articulations du membre inferieur est décisif pour étirer de manière spécifique le tissu ciblé et induire des changements au niveau des propriétés mécaniques des muscles et des nerfs après l’application des protocoles d’étirement aigus et chroniques. De plus l’amélioration de l’AAM était spécifique selon les tissus étirés. / Maximal joint range of motion (ROM) of a joint, or joint flexibility, is an important functional outcome used in clinical practice, sports and research designs to estimate the maximal length of passive muscle-tendon unit (MTU). Maximal ROM was thought to be mainly restricted by the tension developed by MTUs being stretched during articular motion (mechanical-based theory). However, there is a growing body of experimental research suggesting that stretch training induces increases in maximal ROM in the absence of significant mechanical adaptations in MTU (sensorybased theory). More recently, non-muscular structures such as peripheral nerves have been pointed to limit the stretching amplitude. This doctoral research aimed to extend the knowledge about the mechanical role of muscular and non-muscular tissues underpinning the limitation of maximal ROM in-vivo. Taking advantage of ultrasound shear wave elastography to assess the passive stiffness of individual muscles and nerve, four studies were conducted to: examine whether mechanical loading of muscular and non-muscular structures limit the maximal ROM, and if their mechanical properties adapt to either acute or chronic stretch training. The results show that maximal ROM can be limited by either muscular or non-muscular structures, depending on the posture of the entire lower limb which is decisive to stretch preferentially the target tissue. Acute and chronic stretching targeting separately each structure induces changes in mechanical properties of muscles and nerves. In addition, improvements in maximal ROM were specific to the tissues that were more loaded and correlated with the changes in their mechanical properties.

No description available.

Este trabalho tem como objetivo a comparação dos resultados de ensaios de durabilidade em um suporte do eixo traseiro de um veículo leve de passeio, submetido a dois tipos distintos de testes: durabilidade em rodagem real e em simuladores de estradas. Após o término dos ensaios, o componente apresentou resultados diferentes: as trincas podem ser observadas na peça submetida à rodagem real, e os danos não ocorrem no eixo que foi testado em simulador. As discrepâncias citadas podem estar ligadas a possíveis erros, ocorridos durante a transferência dos dados pertinentes ao teste real para o simulador. / The aim of this research is comparing results from durability tests performed at a rear axle bracket of a small passenger car. The part was tested using two different kinds of tests: real (proving ground) durability and simulated (road simulator) durability. After that, the part showed different final results: several cracks can be observed at the part that was tested at the proving ground and no real damage was inflicted at the part that was test at the road simulator. These differences can be related to transferability problems that occurred during data analysis and transfer from real test to a simulated one.

Este trabalho tem como objetivo a comparação dos resultados de ensaios de durabilidade em um suporte do eixo traseiro de um veículo leve de passeio, submetido a dois tipos distintos de testes: durabilidade em rodagem real e em simuladores de estradas. Após o término dos ensaios, o componente apresentou resultados diferentes: as trincas podem ser observadas na peça submetida à rodagem real, e os danos não ocorrem no eixo que foi testado em simulador. As discrepâncias citadas podem estar ligadas a possíveis erros, ocorridos durante a transferência dos dados pertinentes ao teste real para o simulador. / The aim of this research is comparing results from durability tests performed at a rear axle bracket of a small passenger car. The part was tested using two different kinds of tests: real (proving ground) durability and simulated (road simulator) durability. After that, the part showed different final results: several cracks can be observed at the part that was tested at the proving ground and no real damage was inflicted at the part that was test at the road simulator. These differences can be related to transferability problems that occurred during data analysis and transfer from real test to a simulated one.

No description available.

No description available.

Thesis (M.S.)--Brigham Young University. Dept. of Audiology and Speech-Language Pathology, 2006. / Includes bibliographical references (p. 79-84).