601 |
Reducing the electric field sensitivity of a Rydberg state transition by the application of a non-resonant microwave fieldJones, Lucas Alexander 21 August 2012 (has links)
The 87Rb 49s->48s Rydberg state transition was rendered insensitive to electric field fluctuations about a 1V/cm dc electric field. This was accomplished by applying a non-resonant 38.445GHz microwave field to modify the electric dipole moment difference between the two states involved. This effect can be used to preserve the coherence of Rydberg state qubits in the presence of varying electric fields.
|
602 |
Quantification of exhumation in the Cooper-Eromanga Basins, Australia / Angelos Mavromatidis.Mavromatidis, Angelos January 1997 (has links)
Bibliography: leaves 299-320. / xv, 320 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this thesis is to determine the amount of exhumation in the Cooper-Eromanga Basins. The compaction method is applied in order to achieve this aim. The study expands the traditional use of the sonic log as the main 'tool' in compaction-based analysis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1997?
|
603 |
The Kinetics of Electrosterically Stabilized Emulsion Polymerization SystemsThickett, Stuart Craig Vincent January 2008 (has links)
Doctor of Philosophy / The kinetics of electrosterically stabilized emulsion systems was studied. The aim of this was to understand the impact that steric and electrosteric stabilizers have on the kinetics of particle growth and particle formation in the area of emulsion polymerization. The well-established mechanisms that govern these processes for emulsions stabilized by conventional low molecular weight surfactants were used as a reference point for comparative purposes. Model latexes were synthesized that comprised of a poly(styrene) core stabilized by a corona of poly(acrylic acid). The advent of successful controlled radical polymerization techniques in heterogeneous media (via RAFT polymerization) allowed for latexes to be synthesized under molecular weight control. For the first time, the degree of polymerization of the stabilizing block on the particle surface was able to be controlled and verified experimentally using mass spectrometry techniques. Three latexes were made with different average degrees of polymerization of the stabilizing block; five, ten and twenty monomer units respectively. A methodology was developed to remove the RAFT functionality from the polymer chains present in the emulsion while retaining the desired particle morphology. Oxidation with tertbutylhydroperoxide (TBHP) was proven to be successful at eliminating the living character provided by the thiocarbonyl end-group. Extensive dialysis and cleaning of the latex was performed to ensure no residual TBHP or reaction by-products remained. Latexes with poly(styrene) cores were chosen for this work as poly(n-butyl acrylate) latexes were shown to be influenced by chain transfer to polymer, providing an additional kinetic complication. The three electrosterically stabilized emulsions were used as seed latexes in carefully designed kinetic experiments to measure the rate of polymerization as a function of time. Two independent techniques (chemically initiated dilatometry and γ-relaxation dilatometry) were used to measure the rate coefficients of radical entry (ρ) and exit (k) in these systems – the two parameters that essentially govern the rate of particle growth. The latexes were chosen such that they satisfied ‘zero-one’ conditions (i.e. that any given latex particle contains at most one growing radical at any given time) in order to simplify data analysis. Three different chemical initiators were used, each yielding a radical with a different electric charge. Results from γ-relaxation experiments demonstrated that the three electrosterically stabilized latexes gave very long relaxation times when removed from the radiation source, ultimately yielding very small k values. These values were up to a factor of 10 smaller than that predicted by the ‘transfer-diffusion’ model for exit for particles of that size. This reduction was attributed to a ‘restricted diffusion’ effect, where the exiting monomeric radical has to diffuse through a dense layer of polymer on the particle surface, where its mobility will be restricted. Modification of the Smoluchowski equation for diffusion-controlled adsorption/desorption to account for this postulate led to the development of a model that gave excellent semi-quantitative agreement with experiment. Chemically initiated dilatometric experiments (using three different types of initiator) gave the unusual result of very low reaction rates and low steady-state values of 'nbar', the average number of radicals per particle. Using the standard kinetic equations for styrene-based systems (where it is assumed that an exited monomeric radical undergoes re-entry), this led to the calculation of impossibly small values of the entry rate coefficient ρ (far below any background or ‘thermal’polymerization rate). However upon removing the assumption of re-entry and assuming that exited radicals undergo termination, the obtained values of ρ were in almost perfect agreement with the values predicted from the ‘control by aqueous phase growth’ entry mechanism. This unexpected result was attributed to chemical reaction with the poly(acrylic acid) stabilizers through chain transfer to polymer (via hydrogen-atom abstraction). This postulate was verified by separate experiments that demonstrated that poly(acrylic acid) could act as a reasonably efficient chain transfer agent for styrene polymerization. The addition of poly(acrylic acid) to the aqueous phase of a conventionally stabilized emulsion also led to the rate reduction seen previously. NMR experiments demonstrated the existence of poly(acrylic acid-graft-styrene), which could only be formed through termination of a poly(styrene) chain with a poly(acrylic acid) chain bearing a mid-chain radical (as the product of a chain transfer reaction). These additional terms of transfer and termination were included in the governing kinetic equations of emulsion systems (the Smith-Ewart equations) to develop a model to account for the behaviour of electrosterically stabilized latexes. The ultimate fate of an exiting radical was now shown to be a competition between fates; successful desorption into the aqueous phase, or chemical reaction (through transfer or termination) within the hairy layer. These additional terms were shown to significantly reduce the theoretical value of nbar, and were in excellent agreement with experiment. For small electrosterically stabilized particles with a densely packed ‘hairy layer,’ it was seen that transfer/termination is the dominant loss mechanism as opposed to desorption. The developed model showed that as the particle size was increased, the dominant loss mechanism once again became successful desorption into the aqueous phase. The model was shown to give excellent agreement with experimental data from ‘uncontrolled’ emulsion systems. To explain the highly unusual secondary nucleation behaviour seen in systems such as these, it was postulated that beta-scission of a poly(acrylic acid) chain bearing a mid-chain radical is an important mechanistic step in the nucleation mechanisms of these systems. Modelling (both steady-state and time-dependent) gave good agreement with experiment with a minimal number of adjustable parameters. Theory (and supporting experimental evidence) demonstrated that this nucleation mechanism is only significant at high particle numbers; under other conditions the well-known ‘homogeneous nucleation’ mechanism is once again dominant.
|
604 |
Deformation and degradation aspects of ballast and constitutive modelling under cyclic loadingSalim, Md Wadud. January 2004 (has links)
Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 238-250.
|
605 |
Modelling of influence of matric suction induced by native vegetation on sub-soil improvementFatahi, Behzad. January 2007 (has links)
Thesis (Ph.D.)--University of Wollongong, 2007. / Typescript. Includes bibliographical references: leaf 224-236.
|
606 |
Experimental study for asphalt emulsion treated baseMoss, Steven Phillip, January 2008 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
|
607 |
Karayolu taşıtlarının temel zeminlerinde oluşturduğu dinamik etkilerin azaltılmasında yeni bir yaklaşım /Ceditoğlu, Deniz. Keskin, Sıddıka Nilay. January 2008 (has links) (PDF)
Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Anabilim Dalı, 2008. / Bibliyografya var.
|
608 |
Effect of soil compaction and organic residues on spring-summer soil moisture and temperature regimes in the Sierra National Forest, California /Troncoso, Guillermo E. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references (leaves 46-48). Also available on the World Wide Web.
|
609 |
Characteristic behaviour of slow moving slidesMansour, Mohamed Farouk Mohamed Ibrahim. January 2009 (has links)
Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on June 29, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geotechnical Engineering, Civil and Environmental Engineering Department, University of Alberta." Includes bibliographical references.
|
610 |
New political economy of exchange rate policies and the enlargement of the EurozoneFahrholz, Christian H. January 1900 (has links)
Thesis (doctoral)--Freie Universität, Berlin, 2004. / Title from e-book title screen (viewed Oct. 15, 2007). Description based on print version record. Includes bibliographical references (p. [143]-155).
|
Page generated in 0.0185 seconds