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羅文惠 and Man-wai Law. "Strain energy capacity of reinforced concrete beams." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31207704.
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Law, Man-wai. "Strain energy capacity of reinforced concrete beams /." [Hong Kong : University of Hong Kong], 1987. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12228175.
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唐嘉鴻 and Ka-hung William Tang. "Strain energy capacity of reinforced and prestressed concrete beams." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B30425190.
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Tang, Ka-hung William. "Strain energy capacity of reinforced and prestressed concrete beams /." [Hong Kong] : University of Hong Kong, 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12925524.
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Al-Aghbari, Mohammed Yousuf Saif. "Bearing capacity of shallow strip foundations with structural skirts resting on dense sand." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367023.
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Hammer, Tor Arne. "Deformations, strain capacity and cracking of concrete in plastic and early hardening phases." Doctoral thesis, Norwegian University of Science and Technology, Department of Structural Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1789.
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Field observation reveals that cracking of free concrete surfaces in the period before and during setting, may appear at two basically different ages: Minutes after surface finishing, here called “plastic phase” and at some hours after surface finishing, here called “early hardening phase”. This has been verified by tests in the present work by investigating the deformations and strain capacities in both phases, as well as the crack initiation and propagation.
In the plastic phase, the rate of water evaporation relative to the permeability of the concrete (i.e. the ability to transport water to the surface) is the dominating factor. It follows that the “critical” evaporation rate decreases with decreasing permeability, e.g.concretes with relatively low permeability, i.e. with relatively low water-to-powder ratios (like HSC and SCC) have low critical rates.
When the evaporation rate is high relative to the permeability, an important point is the very early formation of capillary tension of pore water (meniscus system) at the surface, which appears as a skin formation. It results in shrinkage of the skin (“plastic shrinkage”), but probably more important, in very low strain capacity of the skin. The latter suggests that deformations caused by differential settlement (as results of reinforcement bars or cross section shifts) and even relatively small external deformations (e.g. formwork movement) may then result in cracking. Furthermore, the skin formation, and thus high cracking risk, may in practise appear before any curing aid is applied.
It is suggested that cracks initiate by emptying of surface cavities (or coarse surface pores): Such cavities will empty (if not already empty) before the pores between the cement grains. Then, there is no meniscus left to restrain the cavities, and they will open as the shrinkage continues.
The fact that both deformation and strain capacity are result of capillary tension of the pore water, suggests that pore water pressure (e.g. as measured in the present work) can be used as a single measure to assess the cracking risk in the plastic phase.
Cracking in the early hardening phase, may be assessed as for hardened concrete, e.g. from the stress-tensile strength ratio, where the stress is result of the restrained drying shrinkage and thermal dilation (autogenous shrinkage may contribute in very low w/b systems).
A promising methodology has been developed to measure deformation, tensile strain capacity, stress generation and tensile strength evolution in the early hardening phase, and the results confirm that the period is critical for cracking. It is shown that the deformation of surfaces in this period caused by moderate drying (here exposed to 20 ºC and 50 % RH) combined with a moderate cooling (here approximately 5 °C), generate restraining stress that may exceed the tensile strength, and thus, generate failure.
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Li, You-Sheng. "Heat capacity measurements of Sr₂RuO₄ under uniaxial stress." Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/16591.
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The most-discussed pairing symmetry in Sr₂RuO₄ is chiral p-wave, pₓ ± p[sub]y, whose degeneracy is protected by the lattice symmetry. When the lattice symmetry is lowered by the application of a symmetry-breaking field, the degeneracy can be lifted, potentially leading to a splitting of the superconducting transition. To lift the degeneracy, the symmetry breaking field used in this study is uniaxial stress. Uniaxial stress generated by a piezo-electric actuator can continuously tune the electronic structure and in situ lower the tetragonal symmetry in Sr₂RuO₄. Previous studies of magnetic susceptibility and resistivity under uniaxial stress have revealed that there is a strong peak in T[sub]c when the stress is applied along the a-axis of Sr₂RuO₄. In addition, it has been proposed that the peak in T[sub]c coincides with a van Hove singularity in the band structure, and measurements of Hc₂ at the maximum T[sub]c indicate the possibility of an even parity condensate for Sr₂RuO₄ at the peak in Tc. In this thesis, the heat capacity approach is used to study the thermodynamic behavior of Sr₂RuO₄ under uniaxial stress applied along the crystallographic a-axis of Sr₂RuO₄. The first thermodynamic evidence for the peak in T[sub]c is obtained, proving that is a bulk property. However, the experimental data show no clear evidence for splitting of the superconducting transition; only one phase transition can be identified within the experimental resolution. The results impose strong constraints on the existence of a second phase transition, i.e. the size of the second heat capacity jump would be small or the second T[sub]c would have to be very close to the first transition. In addition to these results, I will present heat capacity data from the normal state of Sr₂RuO₄. The experimental results indicate that there is an enhancement of specific heat at the peak in T[sub]c, consistent with the existence of the van Hove singularity. The possibility of even parity superconductivity at the maximum T[sub]c has also been investigated. However, the heat capacity measurements are shown to be relatively insensitive to such a change, so it has not been possible to obtain strong and unambiguous evidence for whether it takes place or not.
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Dürrheim, Erna Theresia. "Some physiological effects of deep underground mining and the relationship with physical work capacity and functional work capacity assessment outcomes." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9019.
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Motivation: The South-African deep level gold mining industry has adapted in many ways, as the pursuit for gold has led deep into the earth core, where rock face temperatures measure around 60°C. Ventilation adapted through engineering developments like refrigeration systems, creating cooler work environments to an extent. Despite these developments the risks of high ambient temperatures coupled with strenuous work and dehydration remains, leading to alternative methods of control that have to indicate whether employees have the necessary functional capacity to perform daily work tasks.
Objectives: The objectives of this study were: to measure and compare the physiological effects of the tasks performed by workers in an underground mining environment; To measure the soundness of heart rate as a gauge of work stress in real-life work conditions, taking into account the stressors that influence it; to determine the efficacy of functional and physical work capacity assessments as a method of determining work readiness.
Methods: A study group (n = 16) was chosen to represent the “most exposed” work population, all of whom have previously passed the functional work capacity and physical work capacity assessments. The assessments were repeated and the maximal oxygen uptake assessment was done. The participants were divided into two groups (n = 8) according to their work areas. Measurements were taken over a period of eight consecutive shifts. Each group was later divided into three groups as per the work they performed. Dehydration was determined through urine analysis and body weight changes. Heart rate was observed continuously through a heart rate monitor and oral temperature was measured on an hourly basis.
Results: The shift durations seen during this study were much longer than the customary 8-hour work day. The mean HR results of group I, which was suspected of having the most strenuous work, were very similar to the results for group II and III. This group did, however, have the highest % heart rate ≥ 120 beats per minute and mean cumulative heart beats, group III having the lowest. All of the groups were found to be mildly dehydrated at the end of their shifts, the urine specific gravity indicating that the participants were generally already considerably dehydrated at the onset of the shifts. Group I was the only group whose mean heart rate had a statistically significant correlation (r ≥ 0.5) with % weight loss. There was a statistically significant (p ≤ 0.05) correlation between heart rate and mean oral temperature for all of the groups. The participants that passed the functional work capacity and physical work capacity assessments were found to have performed comparatively better during the real-time shifts than those that failed.
Conclusions: Although there were several employees that had a high mean maximum heart rate, none of the mean heart rates were higher than the self-pacing rate of 110 beats per minute. This ability of self- pacing was seen in the way the participants were able to manage energy expenditure by alternating between heavy and lighter tasks. A great concern is the fact that all of the participants had a % weight loss (0.9 – 2.8% weight loss) indicative of mild dehydration after the shifts, on top of morning urine specific gravity samples (1.020 – 1.025) showing signs of considerable dehydration. Several correlations were found between the functional work capacity and physical work capacity assessments and maximum temperature, maximum heart rate and maximal oxygen uptake, suggesting a significant relationship between the real life situation and the homogenous laboratory setting. comparing the employees that passed the functional work capacity and physical work capacity assessment to those that failed, a marked difference was seen in their respective performances. The groups that passed had a lower mean heart rate and maximum heart rate and higher maximal oxygen uptake. It may, therefore, be concluded that the functional work capacity and physical work capacity assessments provide a valid evaluation of an individual’s work capacity and potential to cope with the varying demands of underground work.Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.
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Peng, Jun, and 彭軍. "Effects of strain gradient on maximun concrete stress and flexural capacity of normal-strength RC members." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43085787.
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Peng, Jun. "Effects of strain gradient on maximun concrete stress and flexural capacity of normal-strength RC members." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43085787.
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Zhou, Chong. "Investigation of micro- and macro-phenomena in densely packed granular media using the discrete element method." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/4899.
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Granular materials are in abundance in nature and are estimated to constitute over 75% of all raw materials passing through the industry. Granular or particulate solids are thus of considerable interest to many industrial sectors and research communities, where many unsolved challenges still remain. This thesis investigates the micro- and macro-phenomena in densely packed particulate systems by means of the Discrete Element Method (DEM), which is a numerical tool for analysing the internal complexities of granular material as the mechanical interactions are considered at the grain scale. It presents an alternative approach to phenomenological continuum approaches when studying localisation problems and finite deformation problems in granular materials. In order to develop a comprehensive theoretical understanding of particulate matter and to form a sound base to improve industrial processes, it is desirable to study the mechanical behaviour of granular solids subject to a variety of loading conditions. In this thesis, three loading actions were explored in detail, which are biaxial compression, rigid object penetration and progressive formation of granular piles. The roles of particle shape and contact friction in each of these loading scenarios were investigated. The resulting packing structures were compared and studied to provide a micromechanical insight into the development of contact force network which governs the collective response. The interparticle contact forces and displacements were then used to evaluate the equivalent continuum stress and strain components thus providing the link between micro- and macroscopic descriptions. The information collected from the evolution of strong contact network illustrates the underlying mechanism of force transmission and propagation. DEM simulations presented in this thesis demonstrate strong capability in predicting the bulk behaviour as well as capturing local phenomenon occurring in the system. The research first simulates a testing environment of biaxial compression in DEM, in which the phenomenon of strain localisation was investigated, with special attention given to the interpretation of underlying failure mechanism. Several key micromechanical quantities of interest were extracted to understand the bifurcation instability, such as force chains, contact orientation, particle rotation and void ratio. In the simulation of progressive formation of granular piles, a counterintuitive pressure profile with a significant pressure dip under the apex was predicted for three models under certain conditions. Both particle shape and preparation history were shown to be important in the resulting pressure distribution. During the rigid body penetration into a granular sample, the contact forces were used to evaluate the equivalent continuum stress components. Significant stress concentration was developed around the punch base which further led to successive collapse and reformation of force chains. Taking the advantage of micromechanical analysis at particle scale, two distinct bearing failure mechanisms were identified as the penetration proceeded. To further quantify the nature of strain mobilisation leading to failure, Particle Image Velocimetry (PIV) was employed to measure the deformation over small strain interval in association with shear band propagation in the biaxial test and deformation pattern in the footing test. The captured images from DEM simulation and laboratory experiments were evaluated through PIV correlation. This optical measuring technique is able to yield a significant improvement in the accuracy and spatial resolution of the displacement field over highly strained and localised regions. Finally, a series of equivalent DEM simulations were also conducted and compared with the physical footing experiments, with the objective of evaluating the capability of DEM in producing satisfactory predictions.
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Garner, Michael Paul. "Loading Rate Effects on Axial Pile Capacity in Clays." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2016.pdf.
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Hakobyan, Anna [Verfasser], and Werner [Akademischer Betreuer] Liesack. "Linking Metabolic Capacity and Molecular Biology of Methylocystis sp. Strain SC2 by a Newly Developed Proteomics Workflow / Anna Hakobyan ; Betreuer: Werner Liesack." Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/1223130215/34.
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Clark, James Michio Hjalmar. "Evaluation of the Protective Capacity of Ice Hockey Goaltender Masks for Three Accident Events using Dynamic Response and Brain Stress and Strain." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32576.
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Since the introduction of helmets the incidence of traumatic brain injuries (TBI) in ice hockey has greatly decreased, but the incidence of concussions has essentially remained unchanged. Despite goaltenders in ice hockey being the only players on the ice for the entire game, few have assessed the performance of ice hockey goaltender masks. In ice hockey, goaltenders are exposed to impacts from collisions, falls and projectiles. The objective of this study was to assess the protective capacity of ice hockey goaltender masks for three accident events associated with concussion. A helmeted and unhelmeted medium NOCSAE headform were tested under conditions representing three common accident events in ice hockey. Falls were reconstructed using a monorail drop. A pneumatic linear impactor was used to reconstruct collisions and projectile impacts were reconstructed using a pneumatic puck launcher. Three impact locations and three velocities were selected for each accident event based on video analysis of real world concussive events. Peak resultant linear acceleration, peak resultant rotational acceleration and rotational velocity of the headform were measured. The University College Dublin Brain Trauma Model (UCDBTM) was used to calculate maximum principal strain (MPS) and von Mises stress in the cerebrum. The results demonstrated the importance of assessing the protective capacity of ice hockey goaltenders masks for each accident, as each event created a unique response. A comparison of unhelmeted and helmeted impacts revealed ice hockey goaltender masks are effective at reducing the risk of both concussion and TBI for falls and projectiles, but less so for collisions. Further, the risk of more serious injuries was found to increase for falls and collisions as impact velocity increased. The results highlight the importance of impacting multiple locations when assessing the protective capacity of ice hockey goaltenders masks, as different impact locations result in unique responses. Overall this study demonstrated ice hockey goaltenders masks capacity to reduce the risk of concussion across three accident events.
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Uslu, Kadir. "Evaluation Of Pile Driving Lead Section." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000212.
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Macků, Martin. "Studium plastických vlastností formovacích směsí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229192.
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The subject of this thesis was to develop a comprehensive methodology for evaluating the plasticity of molding sand. This study was focused on four types of mixtures that are used in the foundry industry. For the evaluation of plasticity was important to provide an indicator of the deformation ability, calculation of deformation and logarithmic transformation for compression. Plasticity methodology was applied in this work only on the pressure effect. Studies of this issue can have a great influence on the production of correct forms due to the ability to withstand tension without breaking form.
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Espinosa, Diego Francisco. "Resilience of Bridges Following Aftershocks." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5199.
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The ability to predict the reduction in capacity of a structure after an earthquake is vital in the process of assessing a structure after a main-shock or an after-shock. Main-shocks are normally followed by a few aftershocks in a short period of time. Researchers in the past have focused for the most part on the effects of main-shocks on buildings. Very little research has been performed on the ability to predict the reduction in capacity of bridges in aftershocks. This thesis focuses on providing a way of assessing the reduction in capacity for main-shocks as compared to aftershocks and the effects and importance of both in a bridge. The reduction in capacity was defined using three different ratios: ultimate force, stiffness, and strain energy ratio. The ratios were computed relative to an undamaged state following both the main-shock scenario and the main-shock combined with aftershock scenario. The force, stiffness, and strain energy quantities were obtained from lateral pushover analyses along the two lateral bridge axes. Probabilistic demand models describing the loss in capacity were formulated by pairing intensity measures, based on real ground motions obtained from previous earthquakes, for the main-shock and aftershock with the capacity ratios, obtained from nonlinear dynamic time history analysis. Additionally, the reduction in capacity was conditioned on residual displacement and intensity measure in an attempt to discover the reduction in capacity ratio due to the contribution of residual displacement and therefore separate contributions from geometrical and material nonlinearities. This thesis demonstrates that the usage of strain energy ratio provides a definition of capacity that ultimately provides the best correlation between capacity and intensity measure.ID: 031001512; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Kevin R. Mackie.; Title from PDF title page (viewed August 8, 2013).; Thesis (M.S.)--University of Central Florida, 2012.; Includes bibliographical references (p. 81-83).
M.S.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Civil Engineering; Structural and Geotechnical Engineering
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Norrmén, Gunilla. "To be or not to be Sick Certified with Special Reference to Physician and Patient Related Factors." Doctoral thesis, Uppsala universitet, Allmänmedicin och klinisk epidemiologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-120559.
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Objectives The aim of this thesis was to assess the importance of general practitioners (GP) and patient related factors for the GPs’ decision to sick certify or not to sick certify the patients. Study population and methods The data were obtained from a cross-sectional questionnaire study of GP-patient consultations. 65 GPs responded to one questionnaire about themselves and one questionnaire about each of the altogether 642 consultations. The patients responded to a questionnaire about themselves and the consultation, altogether 521 consultations. Various combinations of the three questionnaires were used in the four papers on which this thesis is based. Results Among GPs, long experience of family medicine and working part-time were significant determinants for issuing more sick leave certificates. Complaints perceived as clearly somatic by the physician decreased the chance of sick certifications, and complaints resulting in severe limitation of occupational work capacity, as assessed by the patient as well as the physician, increased the chance of sick certification, as did appointments for loco-motor complaints. Among work related factors, high ‘authority over decisions’ and high ‘social support’ were associated with reduced sickness certification probability. Worrying about illness or injury risks from work increased sickness certification. GPs and their patients took a fairly similar view to statements on health related and insurance system related matters. GPs’ opinions seem to have a greater impact than patients’ on the GPs’ decision to sickness certify a patient or not. Conclusions A number of patient and GP related factors were associated with the probability of getting sick certified. The patient’s own judgement of impaired work ability was important for sickness certification, but a shared judgement and decision between the GP and the patient appears probable in most cases.Försäkringsmedicin
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Leo, Riccardo. "The axial response of offshore piles in sand from large scale tests." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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This thesis focuses on deep foundations used in offshore environment, in particular for offshore wind turbines. Piles are necessary when the bearing capacity of the shallow soil layers is not enough to ensure stability. Piles can work on both axial and lateral response. In the thesis only axially loaded piles will be considered. The analysis of the axial behavior of piles should be considered in terms of ultimate capacity as well as the load transfer mechanism between the pile and the soil.
The technical aim of this thesis concerns the understanding of the load transfer curves, their extrapolation and the exploration of load distribution along the pile during a given load. To achieve this, a thorough study of literature on current design methods is carried out and two instrumented piles will be analysed in order to understand how the load is distributed along the pile shaft and how experimental load transfer curves can be extrapolated.
The more general aim of this work is to optimize design procedures and try to reduce the cost related piles and their installation in offshore environment, since it is quite known to be higher than onshore fields, as it will be explained in the first chapter of this thesis.
A geotechnical software IGtH Pile developed by the Institute of geotechnical Engineering (IGtH), Leibniz Universität Hannover will be used in the evaluation of the ultimate capacity and the results will be compared with a Matlab code developed at the IWES research institute.
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Valverde, Rafael Marin. "Envoltória máxima de resistência lateral em estacas através do ensaio de carregamento dinâmico com energia crescente." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-28022018-135052/.
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A capacidade de carga de estacas pode ser determinada experimentalmente através de provas de cargas estáticas ou de ensaios de carregamentos dinâmicos, conforme as prescrições da NBR 6122:2010. Na sua forma tradicional, o ensaio de carregamento dinâmico, fundamentado na teoria da equação da onda unidimensional, consiste em aplicar uma sequência de golpes de energia aproximadamente constante no conjunto de amortecedores colocado sobre a estaca e medir, no seu topo, valores de deformação específica e aceleração em função do tempo. Esse ensaio evoluiu ao longo dos anos com o avanço da tecnologia e com o desenvolvimento de modelos numéricos, que permitem simular a prova de carga estática na estaca ensaiada dinamicamente. Outra evolução, uma verdadeira \"revolução\", foi a introdução do método de energia crescente proposto por Aoki (1989). O presente estudo é uma iniciativa de aprofundamento do método de energia crescente com foco na definição da envoltória máxima de resistência lateral, permitindo recuperar as mobilizações dos atritos no fuste da estaca, perdidas em golpes anteriores ao de máxima energia aplicada, principalmente em camadas próximas ao topo da estaca. Este procedimento foi denominado Método da Envoltória Máxima de Resistência Lateral. É apresentada uma revisão bibliográfica envolvendo provas de cargas estáticas e ensaios de carregamentos dinâmicos para determinar a capacidade de carga em estacas, junto com os métodos analíticos, empíricos e semiempíricos, disponíveis na literatura técnica. São apresentados três estudos de casos de obras no Estado de São Paulo, nos quais foram realizados ensaios estáticos e dinâmicos nas mesmas estacas, sendo 2 pré-moldadas e uma escavada. A aplicação do Método da Envoltória Máxima de Resistência Lateral conduziu a uma definição de maiores capacidades de carga através do CAPWAP, com curvas carga-recalque simuladas aderentes às das provas de cargas estáticas. Além disso, permitiu estimativas mais precisas do efeito de \"setup\" a longo prazo e forneceu maiores detalhes a respeito do comportamento do sistema estaca-solo.The load capacity of piles can be experimentally determined through static load tests or high strain dynamic load tests, as stated with the requirements of NBR 6122:2010. In its traditional form, the dynamic load test, based on the theory of the one-dimensional wave equation, consists of applying a sequence of constant energy blows upon the pile, and by these blows are measured values of deformation and acceleration as a function of time. The traditional method has evolved through technological advances along the years, with the development of numerical models that simulate the static load test of a pile dynamically tested. Another evolution, a true called \"revolution\", was the introduction of a method of increasing energy test created and proposed by Aoki (1989). The traditional method has evolved through technological advances along the years. The present study is an initiative to deepen the increasing energy method focusing on the definition of the maximum lateral resistance envelope, allowing recovering the mobilized resistance along the shaft, lost in blows prior to the maximum applied energy, especially in layers close to the top of the pile. This procedure was called the Maximum Envelope of Shear Strength. A review is presented involving static load tests and dynamic load tests to determine the load capacity on piles, together with the analytical, empirical and semi empirical methods available in the literature. Three case studies from the State of São Paulo are presented, where static and dynamic tests were performed on the same piles, two driven and one cast-in-place piles. The application of the Maximum Envelope of Shear Strength led to a definition of higher load capacities through the CAPWAP, with simulated load-displacement curves with good correlations in comparison with the static load tests. In addition, it allowed for more accurate estimates of the long-term \"set-up\" effect and provided more detail about the behavior of the pile-soil system.
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Ho, Anh cuong. "Optimisation de la composition et caractérisation d'un béton incorporant des granulats issus du broyage de pneus usagés. : application aux éléments de grande surface." Thesis, Toulouse, INSA, 2010. http://www.theses.fr/2010ISAT0024/document.
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Les matériaux de construction par excellence que sont les matériaux à base cimentaire offrent une faible résistance à la traction ainsi qu’une faible capacité de déformation. Ils sont fragiles et particulièrement sensible à la fissuration, notamment la fissuration due au retrait dans le cas d’éléments à grande surface. Des joints de retrait judicieusement espacés permettent de localiser la fissuration et d’éviter le désordre apparent. Malheureusement, ils constituent aussi le point de départ de futurs désordres (pénétration d’agents agressifs, tuilage, etc.). Cette thèse est une contribution au développement d’un nouveau composite cimentaire présentant une capacité de déformation améliorée. Dans cet objectif, des granulats en caoutchouc (G.C.) issus du broyage de pneus usagés ont été utilisés en remplacement partiel du sable. Les résultats obtenus montrent que la présence de ces granulats est préjudiciable vis-à-vis de la rhéologie du matériau à l’état frais mais que l’utilisation d’un superplastifiant et d’un agent de viscosité permet de réaliser les corrections nécessaires. A l’état durci, une chute de la résistance mécanique et du module d’élasticité est observée, en contrepartie la capacité de déformation au stade de la localisation de la macrofissuration est significativement augmentée. Des essais dédiés permettent de démontrer que cette incorporation de G.C. permet de réduire la sensibilité à la fissuration de retrait avec un intérêt évident pour les applications à grande surface comme les chaussées et dallages sur terre-plein. L’influence de la présence de ces G.C. sur la cinétique de la fissuration a été analysée et confirmée par le biais d’une variable d’endommagement et par l’activité (émission) acoustique accompagnant le processus de fissuration.Le potentiel du composite dans les applications à grande surface comme les chaussées en béton a aussi été abordé par le biais de l’indice de qualité élastique qui a confirmé les promesses attendues. Compte tenu du rôle joué par le module d’élasticité du composite sur ces nouvelles propriétés et les applications potentielles, les outils prédictifs de ce module en fonction du dosage en G.C. présentent un intérêt pratique évident. Dans ce sens, cette thèse a permis de tester la pertinence de quelques modèles analytiques. Dans ce cadre, la borne inférieure de Hashin-Shtrikman qui reste perfectible s’est avérée la mieux indiquée.A côté de l’intérêt en termes d’application matériau Génie Civil, l’incorporation de G.C. constitue une voie de valorisation de pneus usagés non réutilisables et une contribution à la protection de l’environnementCement-based materials exhibit low tensile strength and poor strain capacity. They are brittle and are very sensitive to cracking particularly to shrinkage cracking in large area applications. Sawn joints allow shrinkage cracking to be localised a way to avoid unsightly cracking. Unfortunately they are also the starting point of future distress (ingress of aggressive agent, curling, etc.).This work is a contribution to the design of a cement-based material exhibiting an enhanced strain capacity. For a such objective rubber aggregates (RAs) obtained from grinding end of life tyres partly replacing natural sand have been used.Results showed that RAs are detrimental to the properties of the fresh materials (workability and segregation). However the use of optimized content of a superplasticiser and of a viscosity agent allows the required behaviour to be achieved.With regard to harden state, RAs reduce the strength and the modulus of elasticity of the composite but the strain capacity corresponding to the macrocracking formation is significantly improved. Specific tests showed that RAs reduced the propensity of the material for shrinkage cracking, offering an interest for large surface area such as pavements.Analysis by a scalar damage variable and by acoustic emission is in a good agreement with expected effect of RAs on the cracking kinetics and on the mechanical behaviour of the composite.The interest of the rubberized concrete in large area application such as concrete pavements has been studied and confirmed through the Elastic Quality Index. Given the major role of the modulus of elasticity of the composite on the new properties and expected applications, tools aimed to predict this modulus of elasticity as a function of RAs content are of practical benefit. With this purpose, the work allowed the relevance of some analytical models to be tested. In this context, the lower Hashin-Shtrikman bound which remains perfectible proved to be the most appropriate.Finally, apart from application of civil engineering material, the use of RAs from grinding end of life tyres is a solution of recovery of an industrial by-product and a contribution to a clean environment
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Cortas, Rachid. "Nouvelle approche expérimentale pour la maîtrise de la fissuration du béton jeune : influence de la nature et de la saturation des granulats." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209672.
Full textAbstract:
La fissuration d’éléments minces en béton dès le jeune âge correspond à une réalité observée sur des ouvrages en construction. Cette fissuration concerne des bétons courants de bâtiments, pour lesquels les matériaux de qualité optimale ne sont pas toujours disponibles, en particulier au niveau des granulats. Le but de cette thèse est de définir une approche expérimentale d’étude de ces phénomènes et de proposer des interprétations pour les sensibilités relatives à la fissuration en fonction de la nature des granulats et de leurs taux de saturation initiaux. La sensibilité des moyens de mesures existants conçus pour des bétons spéciaux (BAP et BHP) a d’abord dû êtrevérifiée. Un nouveau dispositif expérimental a été développé dans le but de mieux décrire l’évolution de la résistance et de la capacité de
déformation en traction du béton jeune. Les indicateurs globaux (macroscopiques) apparaissent plus sensibles que les indicateurs de la microstructure pour rendre compte des différences de comportement observées. L’évolution du module élastique, du retrait plastique et endogène corrélées à l’évolution de la capacité de déformation et de la résistance en traction permettent de mieux caractériser le risque
potentiel de fissuration par retrait empêché. La fin de prise correspond à une phase critique. L’influence de la saturation des granulats est
indirecte, et résulte des variations du rapport Eau d’ajout/Ciment, à rapport Eau efficace/Ciment constant. La nature des granulats intervient au niveau des évolutions relatives de la résistance en traction et du module élastique. La méthodologie peut être appliquée à l’étude d’autres types de bétons et d’autres paramètres de formulation.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Khan, Inamullah. "Etude expérimentale de la corrosion en béton armé." Thesis, Toulouse, INSA, 2012. http://www.theses.fr/2012ISAT0043/document.
Full textAbstract:
Les objectifs de la thèse sont d’étudier l’influence de la pré-fissuration sur le développement de la corrosion des armatures du béton armé, les corrélations entre les pertes de section d’armatures dues à la corrosion et la fissuration du béton d’enrobage en résultant et l'effet de la corrosion sur les propriétés mécaniques des structures en béton armé soumis à un environnement salin. Les essais ont été réalisées pour étudier les différentes propriétés mécaniques comme la résistance à la flexion, la résistance au cisaillement, etc. Le travail expérimental est constitué de deux parties: dans la première partie des petits échantillons annulaires en mortier ont été testés afin d'observer l'effet des fissures sur la corrosion. Les résultats montrent que quelque soit l’ouverture des fissures, la corrosion démarre en fond de fissure et se propage le long de l’interface acier-béton endommagée en fond de fissure par la création de la fissure. Dans la deuxième partie, une étude approfondie a été réalisée sur une poutre en béton armé qui a été corrodée dans un environnement salin pendant 26 ans et une poutre non corrodée de même âge pour mieux comprendre l'effet de la corrosion sur les propriétés mécaniques (flexion, cisaillement , propriétés mécaniques de l’acier corrodé) d’éléments en béton armé. Un nouveau modèle a été proposé pour la relation entre la largeur des fissures de corrosion et la perte de section d'acierThe thesis aims to study the effect of corrosion on the mechanical properties of reinforced concrete reinforced concrete structures in chloride environment. Experiments were carried out in order to investigate the different mechanical properties such as bending strength, shear strength etc. The experimental work consists of two parts; in the first part small annular cement sand mortar samples were tested in order to observe the effect of cracks on corrosion. Results show that cracks whatever their width allows the corrosion onset at bottom of cracks and along the steel-concrete interface damaged zone caused by the creation of cracks. In the second part an extensive study was carried out on a 26-year-old corroded reinforced concrete beam and a non-corroded of same age in order to better understand the effect of corrosion on reinforced concrete members in flexion and shear. Impact of corrosion on the mechanical properties of steel in reinforced concrete was studied. A new model was proposed for the relationship between corrosion cracks width and loss of steel cross-section
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Bayerová, Anežka. "Expertní kapacity českých politických stran: případová studie obranné politiky." Master's thesis, Vysoká škola ekonomická v Praze, 2016. http://www.nusl.cz/ntk/nusl-261809.
Full textAbstract:
The thesis deals with marginally explored area of expert capacities of the Czech political parties with respect to the different organizational types of selected political parties and movements. The work aims to find out what expert capacities work for these types of political parties, how these experts are recruited in their position, whether it corresponds to their educational background and professional experiences with function, which are they holding in the expert authority. Work is elaborated in the form of case study, which focuses on the activities of defense policy expert commissions. The text is divided into two theoretical and one empirical chapters. The first chapter deals with the process of policy-making, its actors and activities associated with this process. The second chapter defines the various types of political parties first from the mainstream perspective (cadre, mass, catch-all parties), which complements the modern concept of business party and finally there is a typology of S. Wolinetz (office-seeking, vote-seeking, policy-seeking parties). The last empirical chapter presents the case study focused on four Czech political parties (TOP 09, KSČM, ČSSD and political movement ANO 2011) and their access to party expertise. The result of this work is to compare the level of analytical capacity across selected political parties/movements and testing of hypotheses formulated in the introduction of the thesis.
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Sherry, Samuel Thomas. "Carbon Fiber Reinforced Polymer Retrofits to Increase the Flexural Capacity of Deteriorated Steel Members." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104986.
Full textAbstract:
The load-carrying capacity of aging bridge members may at times be found insufficient due to deterioration and a historical trend towards increased truck axle loads beyond their design capacity. Structurally deficient bridges are problematic for bridge owners and users because they restrict traffic usage and require bridges to be posted (operate at less than their ideal capacity). Structural deficiency is the primary motivation for bridge owners to retrofit bridges to meet a specified operating demand. It may be required to replace or retrofit a portion or all of a deficient bridge. The replacement of an entire bridge or even a part of the bridge is generally less desirable than a retrofit solution because retrofits are generally a cheaper alternative to the entire replacement of a structure and usually do not require the bridge's closure. Standard strengthening solutions for corroded members include bolting or welding steel cover plates, replacing sections of the girder, or adding external prestressed tendons. However, these methods also have several challenges, including required lane closures, high installation costs, increased dead weight, and continuing corrosion issues.
One alternative to conventional retrofits is the use of carbon fiber-reinforced polymer (CFRP) laminates, which can be adhered to increase both strength and stiffness. CFRPs are a highly tailorable material with an extremely high strength-to-weight ratio, ease of installation and can potentially mitigate further corrosion concerns. Fiber Reinforced Polymers (FRPs) have already been widely accepted as a means of retrofitting reinforced concrete structures (AASHTO 2012, 2018a; ACI 2002, 2017; National Academies of Sciences, Engineering 2010, 2019) but have not yet been widely adopted in the steel industry due to the retrofit's material limitations (lower elastic modulus [less than 29,000 ksi], unanswered questions related to debonding, and no unified design or installation guides). However, newly developed materials and manufacturing processes have allowed for the economic development of stiffer CFRP materials suitable for steel structures, such as the high modulus (HM) CFRP strand sheet.
This research analytically and experimentally investigates how newly developed HM strand sheets perform in small scale tensile testing and large scale flexural testing (laboratory and in situ testing). During the laboratory testing, these HM strand sheets were compared against normal modulus (NM) CFRP plates to draw conclusions on these different retrofitting materials (strength, stiffness, bond behavior, and applicability of the retrofit). Another central point in examing these different retrofit materials is how CFRPs perform when attached to structural steel with significant corrosion damage. Corrosion damage typically results in a variable surface profile, which may affect a CFRP retrofit's bond behavior. While limited laboratory testing has been conducted on CFRP attached to steel structures with simulated deterioration, the surface profile does not represent realistic conditions. The effects of a variable surface profile on the NM plate material and HM strand sheet were investigated using small scale tensile testing and large scale flexural testing. All the variable surface profiles tested for bond strength were fabricated based on "representative" simulated corrosion samples or on specimens with significant corrosion.
Once all the variables pertaining to the new materials and the effect of a variable surface profile on CFRP retrofits had been examined in a laboratory setting, these retrofitting techniques were implemented on deteriorated in-service steel bridge structures. This research was the first to retrofit deteriorated in-service bridge structures with HM CFRP strand sheets in the United States. This in situ testing was used to compare the laboratory test data of an individually retrofitted girder to the behavior of a single girder that had been retrofitted in a bridge structure. This information was used to verify results on the behaviors of strengthening, stiffening, effects on live load distributions, and modeling assumptions of retrofitted bridge structures.
The results from the laboratory testing and in situ testing of CFRP retrofits on corroded steel structures were synthesized to provide information on performance and design guidance for future retrofits. This dissertation provides additional information on CFRP retrofits applied to variable surface profiles and provides data on new CFRP materials (HM strand sheets). With this information, Departments of Transportation (DOT) can be confident as to where and when different types of CFRPs are a suitable retrofit material for corroded or uncorroded steel structures.Doctor of Philosophy
The capacity of aging bridges may at times be found insufficient due to deterioration and a trend towards increased loading. Structurally deficient bridges are problematic for bridge owners and users because they restrict traffic usage and require bridges to operate at less than their intended capacity. Inadequate capacity are the primary motivation for bridge owners to repair (retrofit) bridges to meet specified traffic demands. Repairs usually do not require the bridge's closure to traffic. Standard repairs for corroded steel members include bolting or welding steel cover plates, replacing sections of the girder, or adding external prestressed tendons. However, these methods also have several challenges, including required bridge closures, high installation costs, increased weight, and continuing corrosion issues. One alternative to conventional repairs is the use of carbon fiber-reinforced polymer (CFRP) laminates, which can be adhered to the deteriorated members to increase strength and stiffness. CFRPs are an extremely versatile material with high strength, high stiffness, ease of installation and can potentially mitigate concerns about further corrosion. Fiber Reinforced Polymers (FRPs) have already been widely accepted as a means of retrofitting reinforced concrete structures(AASHTO 2012, 2018a; ACI 2002, 2017; National Academies of Sciences, Engineering 2010, 2019) but have not yet been widely adopted in the steel industry due to the lack of literature and economical implementation of the CFRPs on steel. However, over the past 20 years, research has been completed on the application of CFRPs on steel, and newly developed materials were created for the economic implementation of CFRP materials suitable for steel structures. In particular, this material is a high modulus (HM) CFRP strand sheet, which has a higher stiffness than a conventional CFRP. This research investigated how newly developed HM strand sheets perform in small-scale laboratory testing and large-scale laboratory testing. Where material strengths, bondability, and the efficacy of different repairs were examined against conventional means on steel structures with and without corrosion deterioration. Once all the variables pertaining to the new materials and the effects corrosion had on CFRP retrofits had been examined in a laboratory setting, these retrofitting techniques were implemented on a deteriorated in-service steel bridge structure (field study) that required repair. This research was the first to repair deteriorated in-use bridge structures with HM CFRP strand sheets in the United States. This information was used to verify results on the material's behavior. The laboratory testing and field testing of CFRP retrofits on corroded steel structures were summarized to provide information on performance and design guidance for future retrofits. This dissertation provides additional information on CFRP repairs applied to corroded steel and provides data on new CFRP materials (HM strand sheets). With this information, Departments of Transportation (DOT) can be confident as to where and when different types of CFRPs are a suitable retrofit material for corroded or uncorroded steel structures.
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Strale, Pierre-Olivier. "Effet de l'inhibition de l'expression de la Cx43 sur les capacités prolifératives et invasives des cellules U251 de glioblastome." Poitiers, 2010. http://theses.univ-poitiers.fr/21982/2010-Strale-Pierre-Olivier-These.pdf.
Full textAbstract:
Pour tenter d'élucider quelles sont les caractéristiques phénotypiques des cellules de glioblastome que contrôle la Cx43, nous avons inhibé son expression dans les cellules U251. Cette approche nous a permis de confirmer que la Cx43 est impliquée dans divers processus associés au développement des gliomes. En effet, si son absence favorise la croissance cellulaire, elle favorise l'angiogénèse tout en diminuant l'adhérence aux protéines matricielles, l'invasion en chambre de Boyden et l'invasion tissulaire ex vivo. Les capacités invasives des cellules de glioblastome étant responsables de la récurrence de ces tumeurs, nous avons tenté d'appréhender l'implication de la Cx43 dans ce phénomène. Tout d'abord, une analyse protéomique par spectrométrie de masse du sécrétome de cellules C6 de gliome de rat suggère que l'effet pro-migratoire induit par l'expression de la Cx43 est contrôlé, au moins en partie, par une composition différente du pool de protéines secrétées [les cytokines (MCP-1, TGF-β binding protein 1, galectine-1), les enzymes protéolytiques (MMP3, cathepsines B et L1), les composants de la matrice extracellulaire (fibronectine, SPARC et collagène α-1) qont notamment sursecrétés par les cellules C6 de gliome de rat exprimant la Cx43]. Par ailleurs, notre étude démontre l'importance des radeaux liquides dans le phénomène d'invasion cellulaire contrôlé par la Cx43. En effet, la désorganisation chimique de ces microdomaines conduit à une diminution drastique des capacités invasives associée à une inhibition des capacités de communication entre les cellules U251 et entre les cellules U251 et les astrocytes en culture primaire. En conclusion, nos résultats suggèrent que la Cx43 joue un rôle complexe voire contradictoire dans le contrôle du phénotype des cellules de glioblastome. En effet, alors que la Cx43 inhibe la prolifération, elle favorise l'invasion, phénomène nécessitant une correcte organisation des radeaux lipidiquesIn order to elucidate what are the phenotypic characteristics controlled by Cx43 in glioblastoma cells, we inhibited its expression, by using the shRNA strategy, in human glioblastoma U251 cells. This approach confirmed that Cx43 is involved in various processes associated to glioma development. Indeed, if its sbsence favors cell proliferation under some conditions (growth in soft agar), it increase angiogenesis while decreasing the adhesion to extracellular matrix proteins, the invasion capacity in Boyden chamber and ex vivo tissue invasion. Moreover, since the invasive capacities of glioblastoma cells are responsible for the tumor recurrence, we were interested to see how Cx43 regulates such capacities. First, a proteomic analysis by mass spectrometry of the secretome of rat glioma cells permitted to consider that such a capacity which is induced by the expression of Cx43 is at least partly mediated by a different pool of secreted proteins [citokines (MCP-1, TGF-β binding protein 1, galectin-1), proteases (MMP3, cathepsins B and L1) and extracellular matrix compounds (fibronectin, SPARC, collagen- α-1) are notably oversecreted by rat C6 glioma cells expressing Cx43]. Second, our study demonstrates that lipid rafts are involved in the invasion process controlled by Cx43. Indeed, the chemically-induced disorganization of these membrane microdomains leads to a drastic decrease of the invasive capacities of U251 cells associated with the inhibition of communication capacities between themselves (homocellular communication) or between them and the astrocytes in primary cultures (heterocellular communication). In conclusion, our results suggest that Cx43 play a complex and even contradictory role in the control of the phenotype of glioblastoma cells. Indeed, while Cx43 inhibits the proliferation of U251 cells, it favors their invasive capacities in association with the presence of lipid rafts
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Abbas, Amina Aicha. "Effet de l’absence d’oxygène sur la capacité de sporulation et les propriétés des spores de Bacillus cereus." Thesis, Avignon, 2014. http://www.theses.fr/2014AVIG0330/document.
Full textAbstract:
L’effet de la température et de la composition du milieu en nutriments sur les propriétés des spores (résistance et germination) de B. cereus a été largement étudié contrairement à l'effet de l'anaérobiose. Or, les cellules végétatives de B. cereus peuvent se retrouver dans une grande variété de milieux naturels avec un faible niveau d'oxygène (intestin, sol, lignes de traitement des aliments…) où la sporulation peut avoir lieu. Les spores produites dans ces conditions anaérobies pourraient donc avoir des propriétés particulières. Dans ce travail, un panel de 18 souches de B. cereus appartenant aux groupes phylogénétiques de II à VII a été étudié pour sa capacité à sporuler en anaérobiose dans un milieu de sporulation approprié que nous avons développé (MODS). En anaérobiose, la capacité de sporulation a été plus faible et plus hétérogène qu’en aérobiose. La souche AH187 a produit le niveau de spores le plus important en anaérobiose, elle a donc été choisie pour étudier les propriétés de ces spores. Les spores produites en anaérobiose étaient plus résistantes à la chaleur humide entre 90°C et 100°C, à 1M de NaOH, 1M d'acide nitreux et à la lumière pulsée. Aucune différence dans la résistance à 5 % de peroxyde d'hydrogène ou à 0.25 mM de formaldéhyde, ni aux UV-C, n'a été observée entre les deux conditions. En présence de L- alanine, les spores produites en anaérobiose germaient plus efficacement que celles produites en aérobiose tandis qu’aucune différence dans la germination n’a été observée en présence d'inosine. Aucune différence dans la taille des spores produites dans les deux conditions n’a été observée par microscopie électronique à transmission. Toutefois, les spores obtenues dans des conditions anaérobies avaient un exosporium endommagé ou dans certains cas un exosporium complètement détaché, contrairement aux spores produites dans des conditions aérobies. Afin de comprendre les différences dans la capacité de sporulation de B.cereus entre les 2 conditions, des PCR en temps réel (RT-PCR) ont été utilisées pour étudier l'expression des gènes de l'initiation de la sporulation spo0A, spo0B, spo0F, KinA et kinB. Les cinétiques d'expressions des gènes spo0A, spo0B, spo0F et KinA avaient la même tendance. Ils étaient caractérisés par une expression plus élevée en anaérobiose par rapport à l’aérobiose au début et à la fin de la phase exponentielle de croissance. En outre, l'expression du gène kinB était caractérisée par une augmentation en anaérobiose par rapport à l’aérobiose pour atteindre un pic entre 4 h (milieu de phase exponentielle) et 6 h (début de phase stationnaire) de croissance. Les gènes spo0A, spo0B, spo0F, KinA et kinB sont exprimés de manière différentielle entre l’aérobiose et l’anaérobiose. Ces données pourraient aider à comprendre la différence de capacité de sporulation de B. cereus entre la condition aérobie et anaérobieThe effect of temperature and nutrient composition of the medium on B. cereus spore properties (resistance and germination) has been extensively studied unlike to the effect of anaerobiosis. Nevertheless, B. cereus vegetative cells can be found in a large variety of natural environments with low oxygen level (intestine, soil, food processing line) where sporulation take place. Spores produced in these anaerobic environments could have particular properties. In this work, a panel of B. cereus strains belonging to phylogenetic groups II to VII was studied for their capacity to sporulate in anaerobiosis in an appropriate sporulation medium we developed (MODS). In anaerobiosis, sporulation ability was lower and more heterogeneous than in aerobiosis. The B. cereus AH187 strain produced the highest level of spores in anaerobiosis, it was therefore chosen to study spore properties. Spores produced in anaerobiosis were more resistant to wet heat from 90°C to 100 °C, 1M NaOH, 1M nitrous acid and pulsed light. No difference in resistance to 5 % hydrogen peroxide or 0.25 mM formaldehyde or UV-C was observed between these two conditions. In the presence of L-alanine, spores produced in anaerobiosis germinated more efficiently than spore produced in aerobiosis. No difference in germination was observed with inosine. No difference in the spores size produced in the two conditions was observed by transmission electron microscopy. However, spores obtained under anaerobic conditions had a damaged exosporium, or in some cases a completely detached exosporium, unlike spores produced under aerobic conditions. To understand differences in sporulation ability between both conditions, Real-time reverse transcription-PCR was used to study the expression the expression of sporulation initiation genes spo0A, spo0B, spo0F, kinA and kinB. The kinetics of gene expression spo0A, spo0B, spo0F and kinA had the same trend. They were characterized by a higher expression in anaerobiosis compared to aerobiosis at the beginning and the end of exponential growth phase. Furthermore, kinB gene expression was characterized by an increase in anaerobiosis compared to aerobiosis to achieve a peak between 4 (middle exponential phase) and 6 (early stationary phase) hours of growth. The spo0A, spo0B, spo0F, kinA and kinB genes are differentially expressed between aerobiosis and anaerobiosis. These data may help to understand the difference in B. cereus sporulation capacity between aerobic and anaerobic condition
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Fornasier, Santos Charly. "Entrainement, préparation physique et physiologique cardio-respiratoire appliquée au rugby à XV." Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0716/document.
Full textAbstract:
Le rugby à XV est un sport collectif qui se caractérise en match par des courses et des collisions de hauteintensité très variables selon les positions. La première partie des travaux, qui s’est centrée sur l’analyse del’activité par centrale d’analyse cinématique, a mis en évidence une activité de haute intensité plus importante enCoupe d’Europe qu’en TOP14 qui varie selon les cinq postes de jeu en termes de répétitions d’efforts et dedistances parcourues à haute intensité notamment chez les avants. De plus, ces activités de haute intensitédiminuent en première et deuxième mi-temps et sont différentes selon les positions. En effet, une diminution plusprécoce est observée chez les avants et les trois-quarts ailes, qui est majorée au niveau des accélérations entre lesdeux dernières périodes d’un match pour les avants démontrant un impact de la fatigue. A l’inverse, les arrièresarrivent globalement à maintenir une intensité élevée. Ainsi, au regard des résultats de la première partie, ladeuxième partie des travaux a consisté en la mise en place d’un entraînement par répétition de sprints en hypoxieinduite par hypoventilation à bas volume pulmonaire. Celui-ci a permis une amélioration significative de lacapacité à répéter des sprints après sept séances d’entraînement par hypoventilation chez les joueurs très entraînés,alors qu’aucun changement n’a été observé dans le groupe normoxie. L’entraînement en rugby à XV se caractérisepar la répétition d’efforts de haute intensité à dominante dynamique (courses) et statique (musculation, phases decombat) qui vont impacter le remodelage du ventricule gauche de manière spécifique. La troisième partie a montré,à partir d’échocardiographies de repos en mode 2D-strain, une hypertrophie physiologique majorée chez les avantscomparativement aux arrières. Cette hypertrophie s’accompagne d’une augmentation des pressions de remplissageet une diminution de la relaxation lors de la diastole, notamment chez les avants. Enfin, malgré une torsionventriculaire inchangée, les rotations et les vitesses de rotation sont plus grandes au niveau basal et plus faibles auniveau apical chez les joueurs de rugby à XV. Ainsi, cette thèse CIFRE apporte de nouvelles données au niveaude l’analyse de l’activité, des méthodes d’entraînement facilement applicables pour l’entraîneur, ainsi que desdonnées plus spécifiques à l’évaluation cardiaque de repos pour le clinicienRugby union is a team sport characterized by high-intensity collisions and running efforts during gameswhich are position-dependent. Accounting for the five different positional groups, the first part of this thesisdemonstrated greater high-intensity activity in European cup when compared to the TOP14 rugby unioncompetition; with position-dependent variations in the frequency of repeated high-intensity efforts and the relativedistance of high-speed movements in forwards. A decrease in high-intensity movement parameters was observedduring the first and second halves of a competitive rugby union match. Indeed, the decrease in high-intensitymovements was earlier in forwards and outside backs who peaked in high-intensity accelerations between the lasttwo periods of the game, while backs were able to maintain their high-intensity activity throughout the match.Collectively, the capacity for a player to repeat high-intensity efforts during a rugby union game varied by thelevel of competition and was influenced by the onset of fatigue. In this context, the second part of this thesis was to conduct a repeated-sprint training in hypoxia. Hypoxia was induced by voluntary hypoventilation at low lungvolume. This training protocol has largely improved the repeated-sprint ability performance in highly-trainedrugby union players after seven training sessions of hypoventilation, whereas it was unaltered in the controlnormoxic group. Such training demands in rugby union (characterised by repeated high-intensity efforts indynamic (running) and static (weightlifting, fighting)) have a specific impact on left ventricular remodelling. Thelast part of this thesis, using 2D-speckle-tracking resting echocardiography, demonstrated that LV hypertrophywas greater in forwards when compared to backs and to control group. Systolic function remained unchanged, butdiastolic function was altered, mainly in forwards, with an increase in filling pressures and a decrease in leftventricular relaxation. Finally, left ventricular twisting was similar while rugby union players exhibited lowerapical and higher basal rotations velocities compared to controls. Collectively, this CIFRE research programprovided new data in activity analysis and training methods that are widely applicable to a range of rugby unionprograms and data on left ventricular morphology, function and mechanics for the clinician
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Finkenbinder, David Edward. "An Experimental Investigation of Structural Composite Lumber Loaded by a Dowel in Perpendicular to Grain Orientation at Yield and Capacity." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35055.
Full textAbstract:
The research summarized by this thesis was comprised of an experimental analysis of beams loaded perpendicular to grain at midspan by a bolted double-shear laterally-loaded connection. Connection specimens were loaded monotonically until capacity was reached. Variables of consideration included the loaded edge distance of the connection main member, the span:depth ratio of the main member, and the main member material. Southern pine machine-stress-rated (MSR) lumber, laminated veneer lumber (LVL), and parallel strand lumber (PSL) were the three material types included in the program.
Experimental results were compared with theoretical predictions from three models: the yield theory-based general dowel equations, which are currently the standard for laterally-loaded connection design in the U.S., and two models based upon fracture mechanics. All material property inputs required by the three models, were measured in the experimental program of this research and used to produce theoretical predictions. Comparisons were also made with respect to design values in the form of calculated factors of safety, over-strengths, and design factors of safety.
Test results and observed trends are provided for all connection and material property tests. Notable trends included failure by splitting for all connections at low loaded edge distances, and variable span:depth ratios generally having a negligible effect on both connection and model performance. In most cases, the general dowel equations were more accurate than the two fracture models, however it should be noted that all three models over-predicted connection capacity at low loaded edge distances.Master of Science
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Ways, Justin Andrew. "An Inbred Rat Model of Exercise Capacity: The Path to Identifying Alleles Regulating Variation in Treadmill Running Performance and Associated Phenotypes." Connect to full text in OhioLINK ETD Center, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=mco1201562803.
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Dissertation (Ph.D.)--University of Toledo, 2007."In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biomedical Sciences." Title from title page of PDF document. Bibliography: p. 142-183.
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Momeni, Amir Farid. "Effect of concrete properties and prestressing steel indentation types on the development length and flexural capacity of pretensioned concrete members." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32682.
Full textAbstract:
Doctor of PhilosophyCivil Engineering
Robert J. Peterman
A study was conducted to determine the effect of different concrete properties and prestressing steel indentation types on development length and flexural capacity of pretensioned members. Wires and strands commonly used in the manufacturing of prestressed concrete railroad ties worldwide were selected for the study. Thirteen different 5.32-mm-diameter prestressing wire types and six different strands (four, seven-wire strands and two, three-wire strands) were used to cast prisms with a square cross section. The ratio of concrete to prestressed steel in the test prism’s cross section was representable of typical concrete railroad ties. Thus, geometrical and mechanical properties of test prisms were representative of actual ties in the railroad industry. To understand the effect of concrete-release strengths and slumps on development length, all parameters were kept constant in the prisms except concrete-release strength and slump. To manufacture prisms with different release strengths, all four wires/strands were pulled and detensioned gradually when the concrete compressive strength reached 3500 (24.13 MPa), 4500 (31.03 MPa), and 6000 (41.37 MPa) psi. To determine the effect of different slumps on development length, prisms with different slumps of 3 in. (7.6 cm), 6 in. (15.2 cm), and 9 in. (22.9 cm) were manufactured and all other parameters were kept constant in prisms. All prisms were tested in three-point bending at different spans to obtain estimations of development length based on type of reinforcement, concrete-release strength, and concrete slump. Lastly, a design equation was developed based on experimental data for prediction of development length. In the last phase of load tests, cyclic-loading tests were conducted on the prisms manufactured with wires to evaluate the bond performance of wires with different indentation types under cyclic loading. A total of 210 load tests, including 14 cyclic tests, were conducted. The monotonic-load tests revealed a large difference in the development length of pretensioned concrete members manufactured with different wire/strand types and different concrete-release strengths. Also, the cyclic-load tests revealed a significant difference in bond performance of different wire types under cyclic loading compared to monotonic loading.
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Roger, Céline. "Le parti populaire tchécoslovaque : fonctions et capacités d'adaptations sous différents régimes politiques." Nice, 2000. http://www.theses.fr/2000NICE0065.
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Le parti populaire tchécoslovaque, apparu en 1919, s'inscrit dans le mouvement démocrate chrétien européen. A travers l'histoire de ce parti , c'est également celle de la Tchécoslovaquie que nous pouvons suivre tout en nous interrogeant sur la continuité de cette formation et les éléments qui la composent. Le Parti populaire joua un rôle important pour ce pays en particulier durant l'exil du gou vernement tchécoslovaque à Londres pendant la deuxième guerre mondiale. Après 1948, ce parti sera membre du Front national, entre instrumentalisation et marge de manoeuvre, il sera alors caractérisé par un éloignement des dirigeants par rapport aux membres fidèles à la tradition que représente pour eux cette organisation politique. Le nombre de membres sera contrôlé entre 1948 et 1989, ce ne sera qu'après 1989 qu'il augmentera considérablement, atteignant actuellement 60000. . . .
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Silva, Ilda de Oliveira. "Desenvolvimento de um sensor capacitivo para o monitoramento de umidade do solo." reponame:Repositório Institucional da UFC, 2006. http://www.repositorio.ufc.br/handle/riufc/18606.
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SILVA, Ilda de Oliveira. Desenvolvimento de um sensor capacitivo para o monitoramento de umidade do solo. 2006. 85 f. Dissertação (Mestrado em engenharia agrícola)- Universidade Federal do Ceará, Fortaleza-CE, 2006.Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-23T18:32:39Z No. of bitstreams: 1 2005_dis_iosilva.pdf: 1712264 bytes, checksum: e1beff224eef02111c7e1edfc0ea96fa (MD5)
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The development of a capacitive sensor based on dielectric characteristics of soil was carried through this work. The sensor was designed as a probe. A fiberglass circuit board was chosen to simulate a parallel plate capacitor. To simulate a capacitor with characteristics similar to the ones commercially sold, within electrical isolation, the plates were isolated by varnish of the type used for isolation of car engines. A value of 106 W of the insulation was measured by a multimeter. The sensor was part of an oscillator RC provided by an integrated circuit to perform the oscillator, the 74LS122 a multivibrating oscillator which gave better responses. The RC circuit output was the input of a frequency divider. The IC TC4040 and HEF4040 both similar counters were used in order to verify the output wave forms. The second one provided a uniform and square waveform, although the first one provided an output waveform tending to triangular. The circuit was printed on the plate of the sensor in order to minimize the influence inherent wire capacitance. The data acquisition, monitoring and the probe calibration had been acquired daily, four times a day and with three readings for sixty three days. The temperature also was monitored this way for both systems. The first one installed in a 2" PVC pipe filled with air dry soil, the water drainage was monitored by weighting. In another system had been installed three sensors in a box full filled by humid soil. The calibration of the sensor was supplied by the strain gage. The time response was obtained using the PVC system, whose water was drained, the soil submitted to saturation again and data were acquired by a microprocessor-based system of data acquisition supplying an output of seconds. The factors that had influenced the sensor output had been evaluated, concluding that the temperature influences however not in so significant way as moistures. The moisture significance levels had been of up to 0,01 % contrasting with the ones of the temperature 7 %. This was valid for all the sensors and also strain gage. The statistical models that more fitted the sensors output were the multiple regression followed by the polynomial regression.
O objetivo do trabalho foi o desenvolvimento de um sensor capacitivo de umidade e a calibração do mesmo utilizando o método gravimétrico e a célula de carga. Para simular um capacitor com características próximas às dos comercialmente vendidos, isolaram-se as placas com verniz bi-componente, do tipo utilizado para isolamento de motores de carro. A isolação alcançada, medida pelo multímetro, foi da ordem de 106 W. O sensor fez parte de um oscilador RC implementado utilizando-se o circuito integrado (CI) 74LS122 como “multivibrador”. A saída do circuito RC foi inserida em um divisor de freqüência. Foi feito uso do contador de pulsos TC4040 e de um similar HEF4040, a fim de verificar as respectivas formas de onda de saída. O segundo apresentou uma resposta mais uniforme e a forma de onda quadrada, já o primeiro apresentou uma forma de onda de saída um pouco discrepante, tendendo para uma onda triangular, mas não uniformemente. O circuito foi instalado na placa do sensor com o intuito de minimizar a influência da capacitância inerente aos cabos. O monitoramento dos dados e a calibração do sensor foram efetuados durante sessenta e três dias, sendo verificados quatro vezes ao dia e com três leituras. A temperatura foi também monitorada dessa forma. Para tal, foram empregados dois sistemas. O primeiro foi instalado em um tubo de PVC de 2", contendo solo seco ao ar posteriormente saturado, e monitorou-se a drenagem de água por meio da pesagem em uma balança de precisão. No segundo sistema, foram instalados três sensores em uma caixa contendo solo úmido e a calibração do sensor foi obtida por intermédio da célula de carga. O tempo de resposta foi conseguido usando o sistema de PVC, cuja água foi drenada; efetuou-se novamente a saturação do sistema com água, e verificou-se com um sistema de aquisição de dados a resposta do sensor, que foi da ordem de segundos. Os fatores que influenciaram a resposta do sensor foram avaliados, concluindo-se que a temperatura influencia, porém não de maneira tão significativa quanto a umidade do solo. Os níveis de significância para a umidade foram de até 0,01 % contrastando com os da temperatura de somente 7 %. Válido para todos os sensores, inclusive a célula de carga. O modelo estatístico que mais se adequou à resposta dos sensores foi a regressão múltipla polinomial.
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Binti, Mat Jali Norazrina. "Crack arrest capability of shock resistant PMMA under dynamic loading." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0032.
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Bien que le PMMA possède des bonnes propriétés mécanique et optique, sa fragilité devient un des problèmes à prendre en compte quand on l’utilise. Une méthode consistant à mélanger des nanoparticules de caoutchouc au PMMA a été montrée comme améliorant la résistance àla rupture et aux impacts du matériau composite obtenu. Ce mélange est nommé RT-PPMA(pour rubber toughened PMMA). Lors de cette étude, une classe de RT-PMMA commercial,appelée PMMA Resist est considérée. De manière plus spécifique, la réponse de trois nuances de RT-PMMA différant par leur concentration en particules de caoutchouc est étudiée.La caractérisation thermomécanique consistant en des tests de traction, compression et du cisaillement -compression a été menée sur les trois nuances de RT-PMMA à différentes vitesses de déformation et températures. Les vitesses de déformation s’étalaient entre 10-5s-1et 1200s-1, et les températures étaient comprises entre -50°C et 70°C. Comme attendu,la réponse des nuances de RT-PMMA montre la forte dépendance à la vitesse de déformation,la température et la concentration en particule de caoutchouc. En outre, la sensibilité au blanchiment sous contrainte (stress-whitening) induit par micro-craquelure (crazing) vs.décohésion particule/matrice dépend également des trois paramètres cités précédemment. De plus, une structure complexe de bande de cisaillement est observée sur les nuances de RTPMMA lors de la compression dynamique et du chargement en cisaillement-compression.La capacité d’arrêt de fissures de la classe de RT-PMMA à l’étude a été menée en réalisant des essais d'impact de type Kalthoff and Winkler (KW)-. La vitesse de projectile est comprise entre 50 m/s et 100 m/s. Des plaques avec deux entailles qui servent comme pré-fissures ont été utilisés lors des essais de choc. L’interaction du projectile avec l’échantillon a été enregistré avec une caméra ultra rapide de 105 à 106 images par seconde. L'examen postmortem de la microstructure a été observé en utilisant la microscopie électronique à balayage(SEM). La résistance aux chocs de RT-PMMA dépend fortement de la concentration de particules de caoutchouc. En particulier, une concentration plus élevée de particules en caoutchouc aide à ralentir la fissure et ainsi augmenter la capacité d’arrêt de fissures du matériau structural. Les particules de caoutchouc gênent la propagation de fissures et le blanchiment sous contrainte apparaît le long du chemin de propagation de fissures.Une première tentative de modélisation constitutive pour les trois nuances de RT-PMMA a été réalisée en se basant sur le travail fait par Arruda et Boyce (1995). Les modèles dépendant de la vitesse et de la température ont été calibres en considérant les résultats expérimentaux et la dépendance de quelques paramètres a la concentration de particules en caoutchouc et au trajet de chargement est mise en évidence. Les modèles doivent encore être unifiesWhile PMMA possesses good mechanical and optical properties, its brittleness is one of the issues to be accounted for when using it. An approach consisting in blending small rubber nanoparticles in PMMA has been shown to improve the resistance and impact toughness of the resulting composite material. This mixture is called rubber toughened PMMA or shortly RT-PMMA. In the present study, a class of commercial RT-PMMA, namely PMMA Resist,is considered. More specifically, the response of three grades of RT-PMMA differing by their rubber particle concentration is investigated. A thermomechanical characterization consisting of tension, compression and shearcompression tests has been first carried out on the three grades of RT-PMMA at various strain rates and temperatures. The strain rate range was 10-5s-1 to 1200s-1, and the temperature range was from -50°C to 70°C. As expected, the RT-PMMA grades response exhibits a strong dependence on strain rate, temperature and rubber particle concentration. Moreover,the sensitivity of RT-PMMA to crazing vs particle-matrix debonding induced stress whitening under tension loading also depends on the three above mentioned parameters. Additionally, a complex pattern of shear bands is observed on the RT-PMMA grades under dynamic compression and shear-compression loading. Next, the crack arrest capability of the class of RT-PMMA under consideration has been investigated by carrying out Kalthoff and Winkler (KW)-like impact test. The projectile impact velocity range was 50 m/s to 100 m/s. Double-notched plates representing the precracked structures were used for the impact tests. The interaction between the projectile and the plate was recorded by using a high-speed camera at 105 to 106 frames per second. Post mortem microstructure was observed using scanning electron microscope (SEM). Impact resistance of RT-PMMA is seen to strongly depend on the rubber particle concentration. In particular, a higher rubber particle concentration aids to slow down the crack tip velocity and thus to increase the crack arrest capability of the structural material. Crack propagation is hindered by the rubber particles and particle-matrix debonding induced stress whitening appears at the crack propagation path. A first attempt of constitutive modelling for the three grades of RT-PMMA has been donebased on the work by Arruda and Boyce (1995). The rate and temperature dependent models are calibrated by considering experimental results and the dependence of some parameters on the rubber particle concentration and loading path is evidenced. The models have still to be unified
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Sathiraju, Venkata Sai Surya Praneeth. "Lateral Stability Analysis of Precast Prestressed Bridge Girders During All Phases of Construction." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553252005286553.
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Ferencz, Balázs. "Nosná železobetonová konstrukce objektu administrativní budovy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226920.
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The Master’s thesis is focused on the analysis and design of selected members of load-bearing structure of an administration building according to the ultimate limit states (ULS) and seviceability limit states (SLS). The calculation and the analysis was supported by design software SCIA ENGINEER 2012. Structural analysis deals with the design of the reinforced concrete (RC) flat slab above the 4rd strorey which is particularly supported by RC columns and particularly lies on RC walls. Furthermore, the Master’s thesis contains analysis of some selected columns of last three storeys, column of lowest storey, construction of stairway between 4rd and 5th storeys. The work beside this deals with the calculation and design of foundation of the object. The rest parts of the load-bearing structure are not solved in the Master’s thesis.
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Matušíková, Anna. "Navrhování konstrukcí s FRP výztuží." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225478.
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This diploma thesis presents available FRP software for calculating load bearing capacity of the structures reinforced with FRP and compares them between each other. Furthermore theory and algorithm of my own software is presented here. Load bearing capacity of structures which are reinforced with non-metallic reinforcement and loaded by combination of normal force and bending moment can be solved by my programme. Effects of high temperatures on the concrete structures can be included in the calculation. In the second part of the thesis is calculated load-bearing capacity and deflection of the real beam reinforced with FRP reinforcement and load-bearing capacity of member with FRP reinforcement with effect of elevated temperature. This has been done using my software. Comparison of results from hand calculation and laboratory load-bearing testing is done at the end. This laboratory testing was accomplished by Institute of Concrete and Mansory Structures at our faculty.
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Kneblík, Adam. "Zesilovač pro tenzometry." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217706.
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The thesis deals about method of gain signals from strain gauge bridges. There are mentioned some signal conditioning methods for bridges amplifiers and charactered their properties. In the next part of this thesis are calculated the amplifier errors for various temperature. There are projected individual variants of strain gage amplifiers (instrumentation amplifier AD524, isolation amplifier, switched capacitor based instrumentation amplifier), their properties are compared with strain gage amplifier Vishay P-3500.
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Tunková, Martina. "Městské lázně." Master's thesis, Vysoké učení technické v Brně. Fakulta architektury, 2010. http://www.nusl.cz/ntk/nusl-215713.
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Seay, Cristina Diane. "Analytical verification of the ACI approach of estimating tensile strain capacity of mass concrete." 2005. http://etd.utk.edu/2005/SeayCristina.pdf.
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Thesis (M.S.) -- University of Tennessee, Knoxville, 2005.Title from title page screen (viewed on September 1, 2005). Thesis advisor: Edwin Burdette . Document formatted into pages (vi, 103 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 100-102).
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Lin, Szu-Chi, and 林斯頎. "Effect of Seismic Capacity Evaluation of Reinforced Concrete Structures Considering Different Stress-Strain Models for Confined Concrete." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/48474266673020994003.
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碩士國立臺灣大學
土木工程學研究所
95
Recent researches found stirrup is very crucial to the ductility of whole structure because it offers the confined stress increasing the strength and the ability of deformation of concrete itself, and also improves the bending strength and ductility capacity of structure members. The main idea of this research is to analyse differences caused by different stress-strain models for confined concrete when evaluating seismic capacity, and find the simulation method more approach to actual situation for analysis of reinforced concrete structures. Models of Mander and Kawashima along with others used to modify these two models are considered in this research of total five models. After acquiring relation of moment and curvature of desired cross sections by moment-curvature analysis, the plastic rotation capacity of each structure member can be available to set the hinge properties. Finally, by using pushover analysis with capacity spectrum method, the seismic capacity of structures can be calculated. After these analyses, it is found that the major factor affecting seismic capacity is the ultimate strain of stress-strain curve of confined concrete. The difference between expectations from tops of models’ curves is not big enough to affect seismic capacity significantly. Results from models of 0.9Mander, Kawashima, and K_0.018 are more reasonable, but there are still many other details needed to be further analyzed.
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Vianthi, Agie, and 曹梅花. "Analytical Study of Shear Capacity and Behavior of Highly Flowable Strain Hardening Steel Fiber Reinforced Concrete Panel." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/98580677485341850233.
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碩士國立臺灣大學
土木工程學研究所
103
In recent years, it is well known that adding steel fiber to concrete significantly increases the ultimate shear strength and ductility of concrete. The test for concrete panels subjected to pure in-plane shear loading is deemed necessary to better understand the shear behavior of fiber reinforced concrete (FRC) members. This research aims to investigate and analyze the shear behavior of FRC panels and propose modified MCFT theory for FRC. Six panel specimens with two levels of concrete compressive strengths (normal strength and high strength) are analyzed in this study. It is found that conventional MCFT procedure is not giving a good prediction to FRC. By adjusting the tensile response of crack FRC members, shear behaviors of FRC panel can be well described.
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Wei-TeYeh and 葉偉德. "A Study on Strain Capacity and Skill of Duty Stuff forDisaster Prevention Center – Case of Tainan High - RiseBuildings." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8uh2rm.
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Ashour, Ashraf F., S. A. El-Refaie, and S. W. Garrity. "Sagging and hogging strengthening of continuous reinforced concrete beams using Carbon Fiber-Reinforced Polymer Sheets." 2009. http://hdl.handle.net/10454/2457.
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Chih-Hung, Tseng. "Germanium Channel MOSFETs and Strain-Induced effects on Silicon MOS Capacitor." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1207200622025800.
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Tseng, Chih-Hung, and 曾志宏. "Germanium Channel MOSFETs and Strain-Induced effects on Silicon MOS Capacitor." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/64483652666467292058.
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碩士國立臺灣大學
電子工程學研究所
94
In this thesis, three important topics for discussion for advancement of metal-oxide-semiconductor field-effect transistors (MOSFETs) technology were studied, which are germanium channel Schottky-barrier MOSFETs, high-k dielectrics, and strain-induced effects. Germanium channel was implemented by using Si-cap/epi-Ge/Si substrate and Platinum (Pt) was deposited as metal Schottky-barrier source/drain of p-type MOSFETs. The devices were fabricated by one mask process and there were some elementary results in experiment. Some useful concepts and adjustments were also provided to improve the performance of the process. Hafnium oxide (HfO2) and hafnium-silicate (HfxSi1-xO2) were the materials for research about the electrical properties of high-k dielectrics. They fill the request about lower leakage current at the same equivalent oxide thickness (EOT) as compared with SiO2. The dielectric constant increases with the increase of Hf concentration. The C-V curve of growing HfO2 on the Si-cap/epi-Ge/Si substrate shows a shoulder to prove holes confinement in epi-Ge quantum well. We brought up a mechanical setup to apply external tensile strain. By measuring flat-band voltage shift of MOS capacitor under strain, the reduction of conduction band edge and the upward shift of valence band edge were obtained.
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Fu, Yen-Chun. "Si/Ge optical phonons and Strain-induced effect on MOS capacitor." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2407200800333600.
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Fu, Yen-Chun, and 傅彥鈞. "Si/Ge optical phonons and Strain-induced effect on MOS capacitor." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/99404811350555640063.
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碩士國立臺灣大學
電子工程學研究所
96
In the thesis, we investigate the change of the physical and electrical properties based on Stained-Si. The thesis classifies two major sections：The first section is that we consider the variation of vibration phonon frequency between atoms in Strained-Si observed from micro-Raman spectroscopy. The other is that the flat-band voltage variation of MOS capacitors in Strained-Si. We consider the research purpose that the current property changed obviously with the stress directions on different channel under the strain technology. Because it is not effective and rapid to measure the stress degree of the Strained-Si under slight scale, we observe the change of vibration phonon frequency to predict the stress degree and then we also apply uniaxial and biaxial strain to MOS capacitors in different orientation Strained-Si to observe the shrinking of Silicon conduction band and valence band. The methods are potential to inspect stress degree quickly. The first, we focus on the change of vibration phonon frequency in Silicon observed from micro-Raman spectroscopy and employ the current model, Keating model, to explain the phonon vibration frequency peak at different Brillouin zone(Γ、X、L points).We also rely on the model to obtain the related parameters (Grunesien parameters) of the observed peak and infer the vibration constant from the parameters for Strained-Si. In order to calculate the effect of the vibration phonon frequency of the strained-Si, we start to observe the Raman shift in the experiment and we solve the eignvalue of the vibration equation to verify the biaxial and uniaxial strain. There are different constant ratio coefficient b between Raman-Shift and strain. We can received the stress degree from the constant ratio for different orientation substrate. The stress-strain transforms and the vibration constant is calculated by general tensor analysis and coordinate transform for different orientation substrate. At the same time, we assume the stress-free boundary condition for uniaxial strain. At last, we use ANSYS to simulate the stress degree and compare the error with the coefficient b. The second, we focus on the flat-band voltage variation of MOS capacitors in Strained-Si. We observe the change of the flat-band voltage to infer the different shrinking of the conduction band and valence band under strain. In the experiments, we exploit the strain mechanism to exert uniaxial or biaxial tensile strain. Under the deformation, we measure MOS capacitors in Strained-Si fabricated on the three directions (Silicon (110)). We also observe the the shrinking of the conduction band and valence band with different strain on different substrate. For the change of the flat-band voltage, we adjust the uniaxial and biaxial strain and focus on the shrinking to discuss with the physical phenomenon and confirm the deformation potential theory.
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Chiou, Tz-Rung, and 邱子容. "Semiconductor Assembly Capacity Expansion Multi-Criteria Decision Analysis with Migration across the Strait." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/94147591334771189815.
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碩士國立高雄第一科技大學
運籌管理所
96
The research focus on how Taiwan Semi-conductor industry deal with the transit of investment and make the right strategy of capacity expansion in Mainland China . With the fact that the normal strategic analysis may not cover intact and overall analysis items, to provide the systematic and intact analysis and practical method , this research constructs the tool based on the concent of Multi-criteria Decision Making ,MCDM. Our results can help semi-con management team efficiently make the right strategic decision and raise its capability of high gross margin.
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Chen, Wei-Nam, and 陳韋男. "Entrepreneurship in Cross-strait: A Cross-age Variation Comparison of Environment, Opportunity, Capacity and Activities." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89692173772147968839.
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碩士嶺東科技大學
企業管理系碩士在職專班
103
This study focused on the cross-strait variation in entrepreneurial environment, opportunity, capacity, activity and position in GEM 21 participating countries. Object of study for Global Entrepreneurship Monitor (GEM) 21 countries in 2002 and 2010 years are participating. Data taken from the GEM adult survey database and national experts survey database in 2002 and 2010 years. It was found that, in 2002 and 2010 two-thirds of entrepreneurial conditions in Taiwan, entrepreneurial opportunities and capacity are all negative growth, its trends like innovation-driven economies. Turning to China except government tax policies and the extent of barriers to market opening, the rest are all positive growing conditions. Its trends like efficiency-driven economies. Taiwan holds an early stage entrepreneurial activity rates are growing, its magnitude higher than the three economies, China is also an early stage entrepreneurial activity is growing but lower margin, it is worth the attention of Chinese opportunity early stages of entrepreneurial activity is higher than Taiwan and three economic body.