Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 31, 2008) Vita. Includes bibliographical references.

Este trabalho apresenta um estudo sobre o uso do processo de estampagem incremental empregando chapas de titânio comercialmente puro. O modelo do componente empregado como foco do trabalho foi um implante craniano a base de titânio. Este tipo de implante é usado, por exemplo, em casos de acidentes em que a camada óssea do crânio foi perdida. Com auxílio de um sistema computacional CAD (Computer Aided Design), foi desenvolvido um modelo 3D, a partir de imagens de tomografia computadorizada. Foram determinadas as características mecânicas e biomédicas das chapas de titânio F67 - grau 2 e, através de software CAM, foi possível gerar as trajetórias de ferramenta, utilizadas na usinagem do molde e na estampagem da chapa. Os testes práticos demostraram que a estampagem incremental proporcionou maiores deformações do que a estampagem convencional e qual a estratégia de usinagem que proporcionou a maior homogeneidade na distribuição de espessura e conformidade dimensional das chapas estampadas. / This work present a research about the incremental sheet forming process, using commercially pure titanium sheets. The model of component used like focus on work was a titanium cranial implant. This kind of implant is used, e.g., in cases of accidents where skull bone was lost. With aided of a CAD computacional system (Computer Aided Design), was development a 3D model, with images of computadorized tomography. It was determined the mechanical and biomedical properties of the F67 grade 2 titanium sheet and, through CAM software, it was possible development the tool path, used in the milling mold and sheet forming. The pratical tests showed the incremental forming provided greater than convencional forming and which the tool movement strategy that provided better homogeneity in the thickness distribution and dimensional conformity of the forming sheets.

Este trabalho apresenta um estudo sobre o uso do processo de estampagem incremental empregando chapas de titânio comercialmente puro. O modelo do componente empregado como foco do trabalho foi um implante craniano a base de titânio. Este tipo de implante é usado, por exemplo, em casos de acidentes em que a camada óssea do crânio foi perdida. Com auxílio de um sistema computacional CAD (Computer Aided Design), foi desenvolvido um modelo 3D, a partir de imagens de tomografia computadorizada. Foram determinadas as características mecânicas e biomédicas das chapas de titânio F67 - grau 2 e, através de software CAM, foi possível gerar as trajetórias de ferramenta, utilizadas na usinagem do molde e na estampagem da chapa. Os testes práticos demostraram que a estampagem incremental proporcionou maiores deformações do que a estampagem convencional e qual a estratégia de usinagem que proporcionou a maior homogeneidade na distribuição de espessura e conformidade dimensional das chapas estampadas. / This work present a research about the incremental sheet forming process, using commercially pure titanium sheets. The model of component used like focus on work was a titanium cranial implant. This kind of implant is used, e.g., in cases of accidents where skull bone was lost. With aided of a CAD computacional system (Computer Aided Design), was development a 3D model, with images of computadorized tomography. It was determined the mechanical and biomedical properties of the F67 grade 2 titanium sheet and, through CAM software, it was possible development the tool path, used in the milling mold and sheet forming. The pratical tests showed the incremental forming provided greater than convencional forming and which the tool movement strategy that provided better homogeneity in the thickness distribution and dimensional conformity of the forming sheets.

Este trabalho apresenta um estudo sobre o uso do processo de estampagem incremental empregando chapas de titânio comercialmente puro. O modelo do componente empregado como foco do trabalho foi um implante craniano a base de titânio. Este tipo de implante é usado, por exemplo, em casos de acidentes em que a camada óssea do crânio foi perdida. Com auxílio de um sistema computacional CAD (Computer Aided Design), foi desenvolvido um modelo 3D, a partir de imagens de tomografia computadorizada. Foram determinadas as características mecânicas e biomédicas das chapas de titânio F67 - grau 2 e, através de software CAM, foi possível gerar as trajetórias de ferramenta, utilizadas na usinagem do molde e na estampagem da chapa. Os testes práticos demostraram que a estampagem incremental proporcionou maiores deformações do que a estampagem convencional e qual a estratégia de usinagem que proporcionou a maior homogeneidade na distribuição de espessura e conformidade dimensional das chapas estampadas. / This work present a research about the incremental sheet forming process, using commercially pure titanium sheets. The model of component used like focus on work was a titanium cranial implant. This kind of implant is used, e.g., in cases of accidents where skull bone was lost. With aided of a CAD computacional system (Computer Aided Design), was development a 3D model, with images of computadorized tomography. It was determined the mechanical and biomedical properties of the F67 grade 2 titanium sheet and, through CAM software, it was possible development the tool path, used in the milling mold and sheet forming. The pratical tests showed the incremental forming provided greater than convencional forming and which the tool movement strategy that provided better homogeneity in the thickness distribution and dimensional conformity of the forming sheets.

The aim of this master´s thesis is the design, proposal and production of a functional jig for technological testing of metal sheet by bending in the pre-production stage to the limit bend radius of the steel sheet up to a thickness of 2 mm, or in case of non-ferrous metal to a thickness of 3 mm. The required bending angle is in the range from zero to ninety degrees. The functionality of the jig will be verified by a practical testing of springing. The proposal will be supported by technological and economic calculations and technical - economic evaluation.

Microchimerism arises from the exchange of cells between genetically distinct individuals. The coexistence of genetically distinct cell populations within a single organism has possible effects on health and functioning of individuals immune systems, but the exact mechanisms of action are often not yet known. With the development of microscopic technologies and software for data analysis, the possibilities of detection and phenotyping of these rare cell populations are expanding. My intention in this work is to find maternal microchimerism in embryonic tissues (E13) and intestines of breastfed pups using MHCII/EGFP knock-in mouse model. Several different technologies potentially suitable for the detection of maternal microchimeric cells in offspring tissues (light sheet fluorescent microscopy - LSFM, virtual slide microscopy and flow cytometry) were selected. Advanced analysis of the obtained samples from the light sheet microscopy using the creation of a neural network was used here. The presence of maternal microchimerism was not demonstrated by flow cytometry. Using LSFM, image data were obtained from intestinal samples of suckling pups, which were processed by the neural network method. Data analysis of embryos (E13) obtained by the same method did not allow data analysis due to high...

Urban construction sites require strict control of their environmental impact, which, for vibratory sheet pile driving, can include damage to nearby structures due to ground vibrations. However, the lack of knowledge concerning the generation of soil vibrations makes the prediction of ground vibration levels difficult. This MSc. thesis in particular, focuses on a crucial link in the vibration transfer chain: the sheet pile – soil interface, which is also one of the least documented. The aim of this thesis is first, to carry out a full-scale field test consisting in the monitoring of sheet pile and ground vibrations during sheet pile vibratory driving. And second, to analyze a selected portion of the collected data with focus on the sheet pile – soil vibration transfer. Both aspects of the thesis work aim, more generally, to contribute to the understanding of ground vibration generation under vibratory sheet pile driving. The full-scale field study was performed in Solna in May 2013. It consisted in the vibratory driving of seven sheet piles, out of which three were fitted with accelerometers. During the driving, ground vibrations were measured by accelerometers, the closest ones placed only 0.5 m from the sheet pile line. The design and installation of the soil instrumentation was innovative in as much as accelerometers were not only set on the ground surface but also at three different depths (~ 3 m, 5 m and 6 m). The analysis presented in this thesis is primarily a comparison between sheet pile vibrations and ground vibrations measured 0.5 m from the sheet pile line. The principal aspects considered in the comparison are: the influence of penetration through different soil layers, the sheet pile – soil vibration transfer efficiency, the frequency content of sheet pile and soil vibrations, and differences between toe- and shaft-generated vibrations. The main conclusions from this study are:  Most of the vibration loss occurs in the near field: 90-99% of the sheet pile vibration magnitude was dispersed within 0.5 m from the driven sheet pile. Moreover, the sheet pile – soil vibration transfer efficiency was reduced for higher sheet pile acceleration levels and higher frequencies.  The soil characteristics strongly influence the sheet pile vibration levels. A clear distinction could be made between "smooth" and "hard" driving, the latter being associated with an impact situation at the sheet pile toe.  The focus of ground vibration studies should not only be the vertical vibrations. Indeed, the ground vibrations’ horizontal component was found to be of the same or even higher magnitude than the vertical component.

No description available.

A finite element program is developed to depict the behavior of a sheet pile interlock connection in an axial pull test. Two types of sheet piles, PS32 and PSX32, are considered. The thumb and finger in the interlock of a sheet pile will provide three contact points for connection with another sheet pile. The problem is highly nonlinear in nature which involves large deflections and rotations, elastic-plastic material response, and a nonlinear boundary effect due to multi-contact surfaces. The Updated Lagrangian formulation is adopted in this study. When the response is in elastic range the Updated Lagrangian with Transformation is used while the Updated Lagrangian with Jaumann stress rate is employed when the element starts to yield. An elastic-plastic with isotropic strain hardening material model is used. The yielding of an element is detected by the Von Mises yield criterion. The finite element formulation also includes a moving contact algorithm to incorporate with both geometric and material nonlinearities. Incremental potential of contact forces for a discretized system is constructed such that geometric compatibilities are maintained between contacting bodies. A method to calculate contact tractions from residual load of internal element stresses is employed. The incremental equilibrium equation is solved by a Newton-Raphson technique. Convergence criteria based on incremental displacement, incremental internal energy of the system, and the changes in contact forces can be chosen to advance or terminate the iteration process. / Ph. D.

The Darwin-Hatherton glacial system (DHGS) drains from the East Antarctic Ice Sheet (EAIS) and through the Transantarctic Mountains (TAM) before entering the Ross Embayment. Large ice-free areas covered in glacial sediments surround the DHGS, and at least five glacial drift sheets mark the limits of previous ice extent. The glacier belongs to a group of slow-moving EAIS outlet glaciers which are poorly understood. Despite this, an extrapolation of a glacial drift sheet boundary has been used to determine the thickness of the EAIS and the advanced West Antarctic Ice Sheet (WAIS) during the Last Glacial Maximum (LGM). In order to accurately determine the past and present contributions of the Antarctic ice sheets to sea level changes, these uncertainties should be reduced. This study aims to examine the present and LGM ice dynamics of the DHGS by combining newly acquired field measurements with a 3-D numerical ice sheet-shelf model. The fieldwork included a ground penetrating radar survey of ice thickness and surface velocity measurements by GPS. In addition, an extensive dataset of airborne radar measurements and meteorological recordings from automatic weather stations were made available. The model setup involved nesting a high-resolution (1 km) model of the DHGS within a lower resolution (20 km) all-Antarctic simulation. The nested 3-D modelling procedure enables an examination of the impact of changes of the EAIS and WAIS on the DHGS behaviour, and accounts for a complex glacier morphology and surface mass balance within the glacial system. The findings of this study illustrate the difference in ice dynamics between the Darwin and Hatherton Glaciers. The Darwin Glacier is up to 1500 m thick, partially warm-based, has high driving stresses (~150 kPa), and measured ice velocities increase from 20-30 m yr⁻¹ in the upper parts to ~180 m yr⁻¹ in the lowermost steepest regions, where modelled flow velocities peak at 330 m yr⁻¹. In comparison, the Hatherton Glacier is relatively thin (<900 m), completely cold-based, has low driving stresses (~85 kPa), and is likely to flow with velocities <10 m yr⁻¹ in most regions. It is inferred that the slow velocities with which the DHGS flows are a result of high subglacial mountains restricting ice flow from the EAIS, large regions of frozen basal conditions, low SMB and undulating bedrock topography. The model simulation of LGM ice conditions within the DHGS implies that the ice thickness of the WAIS has been significantly overestimated in previous reconstructions. Results show that the surface of the WAIS and EAIS away from the TAM would have been elevated 600-750 and 0-80 m above present-day levels, respectively, for the DHGS to reach what was inferred to represent the LGM drift sheet limit. Ultimately, this research contributes towards a better understanding of the dynamic behaviour of slow moving TAM outlet glaciers, and provides new insight into past changes of the EAIS and WAIS. This will facilitate more accurate quantifications of contributions of the WAIS and EAIS to changes in global sea level.