Mass selective axial ejection of ions and mass analysis with a stability island with linear quadrupoles with added octopole fields are described. With mass selective axial ejection, quadrupoles with 2.0% and 2.6% added octopole fields have been tested and compared to a conventional quadrupole. The effects of trapping ions at different q values, excitation voltage, scan direction, balanced and unbalanced rf voltages on the rods, and dc applied between the rods have been investigated. The highest scan speeds and highest resolution are obtained with resonant excitation and ejection at high q (q = 0.8). With axial ejection, the quadrupole with a 2.0% added octopole field provides mass resolution and ejection efficiencies similar to a conventional rod set. Quadrupole, dipole and simultaneous dipole-dipole excitation between the x and y rod pairs were compared and no advantage was found with quadrupole or dipole-dipole excitation. The effects of scan speed were investigated and a resolution at half height of about 1600 is possible at scan speeds up to 5000 Th/s. Mass analysis using islands of stability was investigated with a quadrupole with 2.0% added octopole field. The island of stability is formed with auxiliary excitation. The experiments confirm the predictions of the simulations. With the resolving dc applied to the quadrupole so that the Mathieu parameter a>0, conventional mass analysis with applied rf and dc and no auxiliary excitation is possible. In this case use of an island of stability yields similar peak shape and resolution. However with the polarity of the resolving dc reversed so that a<0, only very low resolution can be obtained; the added octopole prevents conventional mass analysis. By using a stability island when a<0, the resolution is substantially improved.

The development of a petroleum reservoir would inevitably induce a rearrangement of the in-situ stress field. The rearrangement of the stress field would then bring about a deformation of the reservoir rock and a change of the permeability. This experimental study was carried out to investigate rock deformation and its impact on axial permeability. Triaxial compression tests were conducted on Berea sandstone, Indiana limestone, Westerly granite and tuff specimens. Axial permeability was continuously measured for Berea sandstone and Indiana limestone during triaxial compression tests. The axial permeability of fractured Westerly granite specimens was also measured during hydrostatic compression tests. Acoustic emission (AE) monitoring was performed to help improve the understanding of rock deformation. Results showed that Berea sandstone and Westerly granite were relatively brittle, while Indiana limestone and tuff were relatively ductile. Rock deformation altered pore structures and the change of pore structures considerably impacted fluid flow through rock. For porous Berea sandstone and Indiana limestone, the destruction of the pore structure by rock deformation led to a decrease in axial permeability. For tight Westerly granite, fractures created by rock deformation significantly improved the ease of fluid flow. Acoustic emission response was found to be strongly dependent on rock type. Brittle Berea sandstone and Westerly granite produced high AE rates during compression tests, while ductile Indiana limestone and tuff generated very low AE rates.

The University of Sheffield has a non-linear finite element analysis program called VULCAN which has been developed in-house over a number of years and has been thoroughly validated. A parametric study has been conducted using this software, which assesses the influence of such factors as load, geometric imperfection, material properties, temperature profile and axial and rotational restraint on the behaviour, of isolated steel columns in fire. This study is then extended to investigate the behaviour of steel columns as part of a larger multi-storey frame, in which axial restraint to thermal expansion of the heated column is provided by the floors above. A method of modelling these effects in VULCAN using a linear spring element to provide axial restraint has been developed and validated. An experimental partner project has been carried out at the University of Ulster, in which steel columns were furnace-tested with various levels of load, slenderness and axial restraint. These tests have been paralleled with analyses using VULCAN and a good correlation with test results has been shown. The VULCAN program was then used to examine the effects of parameters outside the range of the physical constraints imposed by the test facility. A numerical model, capable of assessing the level of axial restraint imparted on a column by a general multi-storey framed structure has been developed, which has a number of levels of complexity, each giving a higher degree of accuracy. Once the level of restraint for a structure has been assessed, the parametric studies and test data can be applied, and conclusions drawn about the behaviour of the frame. The applicability of different mathematical solution procedures to the analysis of these columns, which exhibit snap-through and snap-back behaviour, has been conducted. The arc-length method has been identified as applicable in such cases and a skeleton version of the procedure introduced into the VULCAN program. The program structure of VULCAN has been improved and the format for data input and output has been developed to allow flexibility. A graphical file-viewer program has also been created. Details of these changes are shown in appendices.

No description available.

Mass selective axial ejection of ions and mass analysis with a stability island with linear quadrupoles with added octopole fields are described. With mass selective axial ejection, quadrupoles with 2.0% and 2.6% added octopole fields have been tested and compared to a conventional quadrupole. The effects of trapping ions at different q values, excitation voltage, scan direction, balanced and unbalanced rf voltages on the rods, and dc applied between the rods have been investigated. The highest scan speeds and highest resolution are obtained with resonant excitation and ejection at high q (q = 0.8). With axial ejection, the quadrupole with a 2.0% added octopole field provides mass resolution and ejection efficiencies similar to a conventional rod set. Quadrupole, dipole and simultaneous dipole-dipole excitation between the x and y rod pairs were compared and no advantage was found with quadrupole or dipole-dipole excitation. The effects of scan speed were investigated and a resolution at half height of about 1600 is possible at scan speeds up to 5000 Th/s. Mass analysis using islands of stability was investigated with a quadrupole with 2.0% added octopole field. The island of stability is formed with auxiliary excitation. The experiments confirm the predictions of the simulations. With the resolving dc applied to the quadrupole so that the Mathieu parameter a>0, conventional mass analysis with applied rf and dc and no auxiliary excitation is possible. In this case use of an island of stability yields similar peak shape and resolution. However with the polarity of the resolving dc reversed so that a<0, only very low resolution can be obtained; the added octopole prevents conventional mass analysis. By using a stability island when a<0, the resolution is substantially improved.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 62-64). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 102-103). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 119-121). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 108-109). Also available via the Internet.

Thesis (M. Eng.)--Carleton University, 1988. / Also available in electronic format on the Internet.