Thesis (Ph. D.)--University of Adelaide, 1988. / Typescript. Copies of three papers (2 published), co-authored by the author, in back. Includes bibliographical references (leaves 179-186).

Thesis (Ph.D.) -- University of Adelaide, Dept. of Physics, 1974.

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 259-265). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR51493

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This research investigates the interaction between heavy precast cladding units attached to steel framed buildings. Cladding systems are designed as non-structural components and are not expected to contribute to the energy absorption of the primary structure. However, research has indicated that the cladding system may be designed to reduce the response of the primary structure under seismic excitations. The use of flexible connections between the cladding and primary structural frames may be able to provide beneficial effects to the entire structural response. In this study, a series of earthquake engineering simulations were conducted in OPENSEES to analyze the effects of the flexible connections of the cladding on both a 3 story and 9 story prototype structures. The research focus is on the 3 story structure. The results from 3 story and 9 story structures indicate that the flexible cladding connections have the ability to transfer hysteretic energy from the primary structure to the flexible cladding connections.

<p> A research project is presented to assess the capabilities of Square Hollow Structural Sections for seismic design. This assessment is based mainly on the energy dissipation and ductility measures. An attempt is made to establish a preliminary guideline of the maximum slenderness ratio that qualify the aforementioned sections for conservative seismic design. </p> <p> An experimental programme on seven different sections was performed to evaluate the loss in flexural capacity due to inelastic cyclic loads, and to construct the load-deflection and moment-curvature hysteresis loops. </p> <p> A comparison is made between the flange slenderness requirements of both HSS and wide flange rot led sections capable of resisting the same level of inelastic strain reversals for the same number of cycles. </p> / Thesis / Master of Engineering (MEngr)

<p>This thesis is focused on modeling of progressive failure in brick masonry structures. Two distinct strategies are examined, namely meso-modeling and macromodeling approach.</p> <p>In the first part, an advanced constitutive model capable of addressing both pre and post-localization behavior is developed and implemented in a commercial finite element package. A mesoscopic modeling approach is then adopted, in which the structural behavior is examined at the level of constituents, i.e. brick and mortar. The performance of the model is verified by simulating a series of experimental tests reported in the literature. Those include the tests conducted by van der Pluijm (1993), Atkinson et al. (1989), and Page (1983).</p> <p>Later, an alternative approach is developed, based on theory of homogenization, in which a lower bound assessment is employed to predict the directional strength characteristics of the brick masonry. The performance of the model is verified using numerical homogenization which involves a finite element analysis of a periodic unit cell. For both these approaches, the failure envelopes for brick masonry at different orientations of the bed joints are obtained.</p> <p>Finally, a methodology is proposed for a systematic identification of material parameters of a macroscopic failure criterion describing the anisotropic strength characteristics of the brick masonry. This criterion is formulated in the framework of Critical Plane Approach (CPA) and its performance is verified against the experimental data of Page (1981 and 1983).</p> / Doctor of Philosophy (PhD)

New fundamental observables are becoming accessible with the Leading Proton Spectrometers (LPS) of ZEUS and H1. This enables us to test more thoroughly the pQCD mechanism of diffractive Deep Inelastic Scattering (DIS). Calculations of the diffractive cross-section in the small Bjorken x limit have been performed. We have used the microscopic QCD formalism of diffractive DIS to find higher twist corrections to the transverse structure functions and predict the diffractive slope and azimuthal asymmetries. We establish duality correspondence between diffraction into low-mass continuum and vector meson production, and calculate the diffractive contribution to the spin structure functions. / Ph. D.

An experimental investigation was conducted to study the inelastic rotation capability of flush end-plate moment connections. Seven specimens representing two-bolt and four-bolt flush end-plate configurations were tested under cyclic loading. "Quasi-static" or "slow-cyclic" loading histories suggested by SAC and the Applied Technology Council were used to load the specimens. Experimental results for maximum moment resisted by the connections were compared with analytical predictions. Moment strengths of the connections were calculated using yield-line theory to predict end-plate yielding and maximum bolt force calculations including prying action. Experimental results were also compared to previous research with regards to strength and stiffness. The inelastic rotation of connections was calculated and conclusions were drawn on the compliance of these connections with current AISC specifications. / Master of Science

Der inelastische Streuquerschnitt von Neutronen mit 7Li weist keine scharfen Resonanzen und eine relativ niedrige Schwelle von 546 keV auf. Bis zur Aufbruchschwelle von 5291 keV findet die inelastische Streuung ausschließlich durch Emission eines 𝛾 -Quants mit 𝐸𝛾 = 477,6 keV statt. Er ist daher als Referenzquerschnitt geeignet. Lithium ist als 3H-Produzent von technischer Bedeutung für die Entwicklung zukünftiger Fusionsreaktoren oder Salzschmelzenreaktoren. Neuere Messungen des inelastischen Streuquerschnitts weichen signifikant von den bisher evaluierten Daten ab. Daher wurden an der Neutronenflugzeitanlage nELBE am HZDR in einem 170 Stunden dauernden Experiment mittels Flugzeit-Methode an einer 4 mm dicken LiF-Scheibe der Streuquerschnitt von 7Li(n,n’𝛾)7Li bestimmt. Die Flugstrecke der Neutronen beträgt 8,3 m. Es wurden 2 Zoll und 3 Zoll-LaBr3-Szintillatoren sowie HPGe- Miniball-Detektoren zum Nachweis der Gammastrahlung in zwei verschiedenen Datenacquisitionen verwendet. Es wird die Abregung von 7Li★ (477,6 keV) gemessen. Das Experiment profitiert von einem hohen Neutronenfluss (ca. 80 n/s/keV @ 1 MeV) sowie einer genauen Spaltkammer der PTB (H19) zur Neutronenflussbestimmung. Die Energie der Neutronen wird mittels Flugzeit-Methode bestimmt. Eine Geant4-Simulation dient der Korrektur der Transmission der Neutronen zum Target, sowie der Mehrfachstreuung und Selbstabsorption. Die bestimmten Wechselwirkungsquerschnitte der LaBr3- und HPGe-Detektoren sind untereinander konsistent, können die Ergebnisse aus [NBI+16] aber nicht bestätigen, die Abweichungen betragen bis zu 20 %. Die Halbwertszeit der gleichzeitig durch Bremsstrahlung in Luft erzeugten Positroniums wurde auf 116(7) ns bestimmt.:1. Einleitung und Motivation 1 2. Theoretische Vorbetrachtungen 3 2.1. Inelastische Neutronenstreuung 3 2.2. Wechselwirkungsquerschnitt 4 2.3. Bisherige Messungen 5 3. Aufbau und Beschreibung des Experimentes 9 3.1. Photoneutronenquelle 10 3.2. Detektoren und Target 11 3.3. Parallelplattenionisationskammer H19 13 3.4. Datenaufnahme 14 3.5. Triggermechanismen 15 4. Auswertung 19 4.1. Kalibrierung 19 4.1.1. Energiekalibrierung 21 4.1.2. Summing-Korrekturen 21 4.1.3. Effizienz-Kalibrierung 22 4.1.4. Effizienzsimulation 27 4.2. Stabilität der Impulshöhen 33 4.3. Totzeitkorrektur 34 4.4. Neutronenflussbestimmung 35 4.4.1. Spaltereignisbestimmung 35 4.4.2. Transmissionskorrektur 38 4.4.3. Mehrfachstreuung 41 4.5. Energieauflösungskorrektur 43 4.6. Bestimmung der Anzahl der 478 keV γ-Quanten 45 4.7. Gammaproduktionswirkungsquerschnitt 7Li (𝑛,𝑛′𝛾) 49 4.8. Anisotropie der Gamma-Emission 53 4.9. Systematische Unsicherheiten 54 5. Ergebnisse und Ausblick 57 A. Anhang 59 A.1. Dopplereffekt 59 A.2. CFD vs. LED Effizienz 63 A.3. Elektronik 64 A.4. Mehrfachstreuung im LiF 66 A.5. Wechselwirkungsquerschnitte für 7Li(n,n’𝛾) 66 A.6. Addendum zur Bestimmung der 478 keV 𝛾-Quanten 68 Literaturverzeichnis 71 / The inelastic neutron cross section of 7Li has no sharp resonances and a fairly low threshold of 546keV.Below the breakup threshold at 5291keV only one 𝛾-ray is emitted at 𝐸𝛾 =477, 6keV. It is therefore suited as a reference cross section. Lithium has technical usage as a 3H-producer in future fusion reactors as well as in molten salt reactors. But there are recent measurements [NBI+16] disagreeing with already evaluated data. To resolve this dissonance, an 170 h Experiment was carried out at the nELBE facility of the HZDR. A 4 mm thick LiF-disk was used as a target, the neutron flux was determined with a 235U parallel plate fission chamber. The flight path for the 7Li(n,n’𝛾)7Li reaction was 8,3 m. As detectors four two-inch LaBr3-detectors as well as three three-inch LaBr3-detectors and two miniball-type HPGe detectors with three 60 % crystals each were used. The measurement of the cross section is solely a measurement of the de-excitation of the first exited 7Li-State at 477,6 keV. The second exited state at 4,63 MeV already decays via particle emission and thus does not contribute any 𝛾-radiation. The experiment benefits from the high neutron flux at nELBE (80 n/s/keV @ 1 MeV) as well as from the precise fission chamber of the PTB (H19) for the neutron flux calibration. A Geant4- Simulation is used to determine correction factors as the transmission from the H19 to the target as well as the multiple scattering correction and the self absorption of the 477,6 keV 𝛾-Rays. The deduced cross section from both detector types are consistent, but they can’t reproduce the data from Nyman et al. PRC93 (2016). The deviations are up to 20 %. The half life of the by means of bremsstrahlung in air produced positroniums in the experiment is 116(7) ns.:1. Einleitung und Motivation 1 2. Theoretische Vorbetrachtungen 3 2.1. Inelastische Neutronenstreuung 3 2.2. Wechselwirkungsquerschnitt 4 2.3. Bisherige Messungen 5 3. Aufbau und Beschreibung des Experimentes 9 3.1. Photoneutronenquelle 10 3.2. Detektoren und Target 11 3.3. Parallelplattenionisationskammer H19 13 3.4. Datenaufnahme 14 3.5. Triggermechanismen 15 4. Auswertung 19 4.1. Kalibrierung 19 4.1.1. Energiekalibrierung 21 4.1.2. Summing-Korrekturen 21 4.1.3. Effizienz-Kalibrierung 22 4.1.4. Effizienzsimulation 27 4.2. Stabilität der Impulshöhen 33 4.3. Totzeitkorrektur 34 4.4. Neutronenflussbestimmung 35 4.4.1. Spaltereignisbestimmung 35 4.4.2. Transmissionskorrektur 38 4.4.3. Mehrfachstreuung 41 4.5. Energieauflösungskorrektur 43 4.6. Bestimmung der Anzahl der 478 keV γ-Quanten 45 4.7. Gammaproduktionswirkungsquerschnitt 7Li (𝑛,𝑛′𝛾) 49 4.8. Anisotropie der Gamma-Emission 53 4.9. Systematische Unsicherheiten 54 5. Ergebnisse und Ausblick 57 A. Anhang 59 A.1. Dopplereffekt 59 A.2. CFD vs. LED Effizienz 63 A.3. Elektronik 64 A.4. Mehrfachstreuung im LiF 66 A.5. Wechselwirkungsquerschnitte für 7Li(n,n’𝛾) 66 A.6. Addendum zur Bestimmung der 478 keV 𝛾-Quanten 68 Literaturverzeichnis 71