Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 291-304).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 191-196).

The purpose of this study is to analyze reinforced concrete frames subjected to abnormal loads. Structures are rarely subjected to abnormal loads, however, when they are subjected to them, it can lead to a progressive collapse. The World Trade Centers in New York City and the Alfred P. Murrah building in Oklahoma City are examples of structures being deliberately subjected to abnormal loads. Structures can also experience unintentional abnormal loading. Examples include the Ronan Point apartment building in Canning Town, England and Husky Stadium at the University of Washington. Consequently, many analysis and design standards now explicitly account for abnormal loads and try to mitigate their effects. This study presents the development of a nonlinear computer analysis program for reinforced concrete frames. The method of analysis involves discretizing a two dimensional reinforced concrete frame into a series of beam-column elements. The element is linear-elastic, however, its end-sections model nonlinear behaviour of a total member by a series of springs. The springs represent the post-elastic stiffness of the end-sections. The post-elastic stiffness of a member-section is obtained from a post-elastic force-deformation response, which is first obtained by performing sectional analysis on a reinforced concrete section using a public domain computer program. The post-elastic force-deformation responses are modeled as either bilinear or trilinear. So-called stiffness degradation factors, which are defined as the ratio of elastic to elastic plus post-elastic deformation of a member-section, are used in modifying the elastic stiffness coefficients in the element stiffness matrix to account for the nonlinear behaviour. Once a reinforced concrete frame enters the post-elastic range of response the analysis procedure becomes incremental. The stiffness degradation factors are calculated at each load increment and the degree of post-elastic stiffness degradation is progressively tracked throughout the load history. The program also has the capability of performing a progressive collapse analysis whereby debris loads caused by falling members are calculated and applied to the structure. A series of example problems are presented to demonstrate the computer analysis program.

The automotive industry is in a state of flux at the moment. Traditional combustion engine technologies are becoming challenged by newer, more efficient and environmentally friendly propulsion methods. These include bio-fuel, hybrid, and hydrogen fuel-cell technologies. Propulsion alone, however, is not the only area where improvements can be made in vehicle efficiency. Current vehicle research and development focuses heavily on propulsion systems with relatively few resources dedicated to auxiliary systems. These auxiliary systems, however, can have a significant impact on overall vehicle efficiency and fuel economy. The objective of this work is to improve the efficiency of a Fuel Cell Electric Vehicle (FCEV) through intelligent auxiliary system control. The analysis contained herein is applicable to all types of vehicles and may find applications in many vehicle architectures. A survey is made of the various types of alternative fuels and vehicle architectures from conventional gasoline vehicles to hybrids and fuel cells. Trends in auxiliary power systems and previous papers on control of these systems are discussed. The FCEV developed by the University of Waterloo Alternative Fuels Team (UWAFT) is outlined and the design process presented. Its powertrain control strategy is analyzed with a proposal for modifications as well as the addition of an auxiliary control module to meet the aforementioned objectives. Simulations are performed to predict the efficiency and fuel economy gains that can potentially be realized using these proposed techniques. These gains prove to be significant, with an almost 2% improvement realized through intelligent control of the air conditioning compressor, and further gains possible through other auxiliary power reduction techniques.

Aim: The aim of this study was to investigate the effects of performing an isometric conditioning contraction (CC) consisting of two sets of five seconds maximal voluntary contraction in physically active individuals prior to three sets of Loaded Squat Jumps (LSJ). Method: 5 males and 4 females (mean ± SD: age 25 ± 2 years, height 175 ± 10 cm, body mass 70 ± 15 kg) were assessed on their power output, force production, jump height and velocity on three sets of LSJ on two separate sessions. Each participant attended two sessions in randomized order: a control session (CON) and an experimental session (EXP) separated by at least two hours. The EXP session consisted of a 10 min warm-up followed by 2 x 5 seconds isometric CC, this was proceeded by another two minutes of rest before three sets of LSJ were performed, each set separated by a two-minute rest. During the CON session a two-minute rest, followed by three sets of LSJ, replaced the isometric CC sequence. Results: No significant improvement was found on any of the physical parameters assessed, comparing the CON and EXP session (p > 0.05). The results showed a variance on individual response were some subjects performed better after the CC and others did not . Conclusion: In conclusion, this study evaluated the effect of performing an isometric CC prior three sets of LSJ. The results indicate that an isometric CC consisting of two sets of five seconds maximal voluntary contraction is insufficient to enhance the performance in an LSJ.

This is a M. Eng. degree project at Uppsala University carried out at the Forsmark nuclear power plant in Sweden. The purpose of it is to compare the two codes RELAP5 and TRACE during transient changes in mass flow against experiment. The change in mass flow will create a pressure wave and generate pipe loads. RELAP5 is a transient analysis code used to model thermal hydraulic systems. TRACE is an effort to combine the previous codes TRAC-B, TRAC-P, RAMONA and RELAP5. Both RELAP5 and TRACE has been compared to experiments. These comprise two abrupt valve closures, the closure of an inertial swing check valve (a flapper disc which closes when the flow is reversed) and a pump start and stop. Both RELAP5 and TRACE conforms well to the experiments with the abrupt valve closures. The check valve closes faster in the calculations compared to the experiment, both for RELAP5 as with TRACE. The amplitude of the pressure wave from the closure of the inertial swing check valve is lower compared to the experiment in both RELAP5 and TRACE. Numerical disturbances become visual as very high amplitudes in the time history diagram of the force in TRACE. The check valve oscillates between its open and closed position in RELAP5, but not in TRACE. Both RELAP5 and TRACE conforms well to the pump start. The mass flow decreases faster in both RELAP5 and TRACE compared to the pump stop.

The purpose of this study is to analyze reinforced concrete frames subjected to abnormal loads. Structures are rarely subjected to abnormal loads, however, when they are subjected to them, it can lead to a progressive collapse. The World Trade Centers in New York City and the Alfred P. Murrah building in Oklahoma City are examples of structures being deliberately subjected to abnormal loads. Structures can also experience unintentional abnormal loading. Examples include the Ronan Point apartment building in Canning Town, England and Husky Stadium at the University of Washington. Consequently, many analysis and design standards now explicitly account for abnormal loads and try to mitigate their effects. This study presents the development of a nonlinear computer analysis program for reinforced concrete frames. The method of analysis involves discretizing a two dimensional reinforced concrete frame into a series of beam-column elements. The element is linear-elastic, however, its end-sections model nonlinear behaviour of a total member by a series of springs. The springs represent the post-elastic stiffness of the end-sections. The post-elastic stiffness of a member-section is obtained from a post-elastic force-deformation response, which is first obtained by performing sectional analysis on a reinforced concrete section using a public domain computer program. The post-elastic force-deformation responses are modeled as either bilinear or trilinear. So-called stiffness degradation factors, which are defined as the ratio of elastic to elastic plus post-elastic deformation of a member-section, are used in modifying the elastic stiffness coefficients in the element stiffness matrix to account for the nonlinear behaviour. Once a reinforced concrete frame enters the post-elastic range of response the analysis procedure becomes incremental. The stiffness degradation factors are calculated at each load increment and the degree of post-elastic stiffness degradation is progressively tracked throughout the load history. The program also has the capability of performing a progressive collapse analysis whereby debris loads caused by falling members are calculated and applied to the structure. A series of example problems are presented to demonstrate the computer analysis program.

The automotive industry is in a state of flux at the moment. Traditional combustion engine technologies are becoming challenged by newer, more efficient and environmentally friendly propulsion methods. These include bio-fuel, hybrid, and hydrogen fuel-cell technologies. Propulsion alone, however, is not the only area where improvements can be made in vehicle efficiency. Current vehicle research and development focuses heavily on propulsion systems with relatively few resources dedicated to auxiliary systems. These auxiliary systems, however, can have a significant impact on overall vehicle efficiency and fuel economy. The objective of this work is to improve the efficiency of a Fuel Cell Electric Vehicle (FCEV) through intelligent auxiliary system control. The analysis contained herein is applicable to all types of vehicles and may find applications in many vehicle architectures. A survey is made of the various types of alternative fuels and vehicle architectures from conventional gasoline vehicles to hybrids and fuel cells. Trends in auxiliary power systems and previous papers on control of these systems are discussed. The FCEV developed by the University of Waterloo Alternative Fuels Team (UWAFT) is outlined and the design process presented. Its powertrain control strategy is analyzed with a proposal for modifications as well as the addition of an auxiliary control module to meet the aforementioned objectives. Simulations are performed to predict the efficiency and fuel economy gains that can potentially be realized using these proposed techniques. These gains prove to be significant, with an almost 2% improvement realized through intelligent control of the air conditioning compressor, and further gains possible through other auxiliary power reduction techniques.

<p>Impulse propagation in cardiac muscle is determined not only by the excitable properties of the myocyte membrane, but also by the gross and fine structure of cardiac muscle. Ionic diffusion pathways are defined by the muscle's interconnected myocytes and interweaving interstitial spaces. Resistive variations arising from spatial changes in tissue structure, including geometry, composition and electrical properties have a significant impact on the success or failure of impulse propagation. Although much as been learned about the impact of discrete resistive architecture of the intracellular space, the role of the interstitial space in the spread of electrical activity is less well understood or appreciated at the microscopic scale. </p><p>The interstitial space, or interstitium, occupies from 20-25% of the total heart volume. </p><p>The structural and material composition of the interstitial space is both complex and </p><p>heterogeneous, encompassing non-myocyte cell structures and a conglomeration of </p><p>extracellular matrix proteins. The spatial distribution of the interstitium can vary from confined spaces between abutting myocytes and tightly packed cardiac fibers to large gaps between cardiac bundles and sheets</p><p>This work presents a discrete multidomain formulation that describes the three-dimensional ionic diffusion pathways between connected myocytes within a variable interstitial physiology and morphology. Unlike classically used continuous and discontinuous models of impulse propagation, the intracellular and extracellular spaces are represented as spatially distinct volumes with dynamic and static boundary conditions that electrically couple neighboring spaces to form the electrically cooperative tissue model. The discrete multidomain model provides a flexible platform to simulate impulse propagation at the microscopic scale within a three-dimensional context. The three-dimensional description of the interstitial space that </p><p>encompasses a single cell improves the capability of the model to realistically investigate the impact of the discontinuous and electrotonic inhomogeneities of the myocardium's interstitium.</p><p>Under the discrete multidomain representation, a non-uniformly described interstitium </p><p>capturing the passive properties of the intravascular space or variable distribution and </p><p>composition of the extracellular space that encompasses a cardiac fiber creates an </p><p>electrotonic load perpendicular to the direction of the propagating wavefront. During </p><p>longitudinal propagation along a cardiac fiber, results demonstrate waveshape </p><p>alterations due to variations in loads experienced radially that would have been otherwise masked in traditional model descriptions. Findings present a mechanism for eliminating myocyte membrane participation in impulse propagation, as the result of decreased loading experienced radially from a non-uniformly resistive extracellular space. Ultimately, conduction velocity increases by decreasing the "effective" surface-to-volume ratio, as theoretically hypothesized to occur in the conducting Purkinje tissue.</p> / Dissertation

A finite element model based on the layer-wise theory and the von Kármán type nonlinear strains is used to analyze damage in laminated composite beams. In the formulation, the Heaviside step function is employed to express the discontinuous interlaminar displacement field at the delaminated interfaces. Two types of the most common damage modes in composite laminates are investigated for cross-ply laminated beams using a numerical approach. First, a multi-scale analysis approach to determine the influence of transverse cracks on a laminate is proposed. In the meso-scale model, the finite element model based on the classical laminate theory provides the material stiffness reduction in terms of the crack density by computing homogenized material properties of the cracked ply. The multiplication of transverse cracks is predicted in a macro-scale beam model under bending loads. In particular, a damage analysis based on nonlinear strain fields in contrast to the linear case is carried out for a moderately large deformation. Secondly, the effect of delamination in a cross-ply laminated beam under bending loads is studied for various boundary conditions with various cross-ply laminate lay-ups. The crack growth of delamination is predicted through investigating the strain energy release rate. Finally, the interactions of a transverse crack and delamination are considered for beams of different configurations. The relationships between the two different damage modes are described through the density of intralaminar cracks and the length of the interlaminar crack. It is found that geometric nonlinearity plays an important role in progression of interlaminar cracks whereas growth of intralaminar cracks is not significantly influenced. This study also shows that the mixture of fracture mode I and II should be considered for analysis of delamination under bending loads and the fracture mode leading delamination changes as the damage develops. The growth of delamination originated from the tip of the transverse crack is found to strongly depend on the thickness of 90- degree layers as well as the transverse crack density. Further, the effect of interfacial crack growth on the transverse cracking can be quatitatively determined by the delamination length, the thickness of 90-degree layers and the transverse crack density.