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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

The development and implementation of a beam position monitoring system for use in the FONT Feedback System at ATF2

Apsimon, Robert J. January 2011 (has links)
Feedback On Nanosecond Timescales (FONT) is a feedback system being developed to correct the beam position jitter in the extraction line and final focus system at the Accelerator Test Facility (ATF2), Tsukuba, Japan. FONT5 is currently being tested and is used to correct the intra-train jitter for a 3-bunch train; the bunch spacing is 154ns. This system measures the position of an electron bunch, using beam position monitors (BPMs). From this measurement, digital feedback electronics calculate the required correction, and sends a pulse to a feedback kicker. The feedback kicker then deflects the next bunch in the train in order to correct its position. Stripline BPMs are used at ATF2, and analogue processors manipulate the BPM signals before they are interpreted by the feedback electronics. The BPM system has been modelled and tested so that it can be parameterised and optimised. The BPMs are calibrated regularly, and the resolution of the system measured. Both of these properties have been analysed and modelled. This has allowed the resolution to be minimised. The resolution is an important factor which limits the achievable feedback correction. Several other factors have also been investigated; these include the feedback gain and the bunch-bunch correlation. To allow the feedback electronics to be controlled remotely, several data acquisition systems (DAQs) have been developed to allow data flow both to and from the digital board. The DAQs have been designed specically for the firmware on the FONT digital board.
112

Analysis of Stochastic Methods for Predicting Particle Dispersion in Turbulent Flows

Sala, Kyle 19 September 2013 (has links)
The current research seeks to develop a computational model that accurately describes particle dispersion in turbulent ow. Current particle dispersion models do not accurately predict the small-scale clumping of particles in turbulent ow that occurs due to interaction with turbulent eddies. A new stochastic vortex structure (SVS) model was developed and compared with current stochastic Lagrangian models (SLM) for turbulent ows. To examine what characteristics of the uid ow eld that lead to dispersion of particles, a number of non trivial measures were used. A discrete-element model is used to transport particle locations for cases with and without adhesive forces. Direct numerical simulations (DNS) are used as a baseline for comparison between the two models. Initial results show that the SVS model matches the spatial structure of the ow eld of DNS reasonably well, while the SLMs do not. Investigation of particle collision rate suggest that while SVS matches the large length scales of ow, it omits the smaller scales of the ow.
113

Possible observational effects of extra forces in extra dimensional models. / 額外次元模型內由額外力所導致的可測結果 / Possible observational effects of extra forces in extra dimensional models. / E wai ci yuan mo xing nei you e wai li suo dao zhi de ke ce jie guo

January 2006 (has links)
Li King Fai = 額外次元模型內由額外力所導致的可測結果 / 李敬輝. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 101-105). / Text in English; abstracts in English and Chinese. / Li King Fai = E wai ci yuan mo xing nei you e wai li suo dao zhi de ke ce jie guo / Li Jinghui. / Chapter 1 --- Prologue --- p.1 / Chapter 1.1 --- Research Background --- p.1 / Chapter 1.2 --- Statement of the Problem --- p.4 / Chapter 1.3 --- Organization of the Thesis --- p.5 / Chapter 2 --- Review of Various Extra Dimensional Models --- p.6 / Chapter 2.1 --- General Relativity --- p.6 / Chapter 2.2 --- Kaluza-Klein Theory --- p.9 / Chapter 2.3 --- Space-Time-Matter Theory --- p.13 / Chapter 2.4 --- Arkani-Hamed-Dimopoulos-Dvali Scenario --- p.16 / Chapter 2.5 --- Randall-Sundrum Scenario --- p.19 / Chapter 3 --- Review of Extra Forces --- p.27 / Chapter 3.1 --- Definition of Force in 4D --- p.27 / Chapter 3.2 --- Extra Forces in STM Theory --- p.28 / Chapter 3.3 --- Variation of4D Mass --- p.31 / Chapter 3.4 --- Position-Momentum Uncertainty Relation --- p.32 / Chapter 3.5 --- Extra Forces in Brane Theories --- p.34 / Chapter 4 --- Extra Forces in the 5D Friedmann Universe --- p.37 / Chapter 4.1 --- Generalized Robertson-Walker Metric --- p.38 / Chapter 4.2 --- Unobserved Motions in Extra Dimensions --- p.43 / Chapter 4.3 --- Equations of Motion with Three Extra Spatial Dimensions --- p.51 / Chapter 4.4 --- Summary --- p.53 / Chapter 5 --- Extra Forces in the Randall-Sundrum Model --- p.55 / Chapter 5.1 --- Model Development - Evolving Extra Dimension --- p.56 / Chapter 5.2 --- Classical Particle Trajectories --- p.59 / Chapter 5.3 --- Unobserved Motions in Extra Dimensions --- p.66 / Chapter 5.4 --- Modification of RSI model --- p.72 / Chapter 5.5 --- Summary --- p.77 / Chapter 6 --- Comments on Extra Forces as the Source of Quantum Fluctuations --- p.78 / Chapter 7 --- Particle-Antiparticle Pairs as an Observable Effect of Extra Force --- p.80 / Chapter 7.1 --- Reasons for Antiparticles --- p.81 / Chapter 7.2 --- Attempts in Classical Physics --- p.85 / Chapter 7.3 --- 5D Kaluza-Klein Scenario --- p.86 / Chapter 7.4 --- Generalizations to Brane Theories --- p.89 / Chapter 7.5 --- Summary --- p.97 / Chapter 8 --- A Summary of this Thesis --- p.99 / Bibliography --- p.101
114

Equações de movimento para excitações nucleares partícula-partícula. / Equations of motion for particle-particle nuclear excitations.

Galeao, Alfredo Pio Noronha Rodrigues 30 June 1980 (has links)
Desenvolvemos uma nova técnica de equações de movimento para excitações nucleares partícula-partícula. Para isso, foi estendido o formalismo de duplos-comutadores de Rowe, relaxando-se a condição de aniquilação do estado-pai, violada no presente caso. As equações foram testadas para estados com senioridade nula de 2, 4 e 6 partículas sujeitas a uma força de emparelhamento, estando os resultados em excelente concordância com a solução exata. Foram também calculados, usando-se as novas equações e uma hamiltoniana realística, os estados de baixa energia com J = 0+, 2+, 4+, 6+ e 8+ para o 210,212,214Pb e 0+, 2+, 4+ e 6+ para o 206,204,202Pb. Tanto as energias de excitação como as taxas de transição (t,p) ou (p ,t) para esses estados concordam bem com as obtidas por um cálculo convencional de modelo de camadas de McGrory e Kuo e com os dados experimentais. O formalismo deverá ser útil para a análise de reações de transferência de dois núcleons. / A new equations-of-motion technique for particle-particle excitations in nuclei is developed. To this end Rowe\'s double-commutator formalism was extended, relaxing the condition of annihilation of the parent state, which is violated in the present case. The new equations were tested for seniority-zero states of 2, 4 and 6 particles interacting with a pairing force, and the results are in excellent agreement with the existing exact solution. Also computed, using the new equations and a realistic Hamiltonian, were the low energy states with J = 0+, 2+, 4+, 6+ and 8+ the case of 210,212,214 Pb and 0+, 2+, 4+ and 6+ in the case of 206, 204,202Pb. Both the excitation energies and the transition rates for the (t,p) or (p,t) \"reaction leading to those states are in as good an agreement with the experimental data as those obtained in a conventional shell-model calculation performed by McGrory and Kuo for some the above isotopes. The present formalism should be of interest for the analysis of two-nucleon transfer reactions.
115

Spin scattering of a particle in random media.

January 2001 (has links)
Chu Lam Long. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaf 81). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- One-dimensional Open-ended Lattice --- p.3 / Chapter 2.1 --- Propagation rules --- p.3 / Chapter 2.2 --- Propagation velocity --- p.6 / Chapter 2.3 --- Propagation direction --- p.7 / Chapter 2.4 --- Number of visits --- p.11 / Chapter 2.5 --- Lattice pattern --- p.13 / Chapter 3 --- Statistical Behaviour of One-dimensional Open-ended Lattice --- p.15 / Chapter 3.1 --- Probability function of first visit --- p.15 / Chapter 3.2 --- Long-time large-distance behaviour of first visit probability func- tion --- p.22 / Chapter 3.3 --- Total probability function --- p.24 / Chapter 4 --- Simulation Results of One-dimensional Open-ended Lattice --- p.26 / Chapter 4.1 --- Number of visits --- p.26 / Chapter 4.2 --- Average propagation velocity --- p.29 / Chapter 4.3 --- Probability function of first visit --- p.32 / Chapter 4.4 --- Total probability function --- p.35 / Chapter 5 --- One-dimensional Periodic Lattice --- p.40 / Chapter 5.1 --- Periodic Boundary Condition --- p.41 / Chapter 5.2 --- Propagation direction --- p.42 / Chapter 5.3 --- Cycle of the particle --- p.42 / Chapter 5.4 --- Lattice pattern --- p.44 / Chapter 5.4.1 --- One cycle --- p.44 / Chapter 5.4.2 --- Two cycles --- p.51 / Chapter 5.5 --- Period of the system --- p.51 / Chapter 5.5.1 --- General case --- p.51 / Chapter 5.5.2 --- Lattices of alternating spin up and spin down --- p.52 / Chapter 5.6 --- Period of the particle --- p.53 / Chapter 5.7 --- Propagation velocity --- p.56 / Chapter 6 --- Statistical Behaviour of One-dimensional Periodic Lattice --- p.57 / Chapter 6.1 --- Average propagation velocity --- p.57 / Chapter 6.2 --- Probability function --- p.58 / Chapter 7 --- Simulation Results of One-dimensional Periodic Lattice --- p.63 / Chapter 7.1 --- Trajectory of the particle --- p.63 / Chapter 7.1.1 --- General case --- p.63 / Chapter 7.1.2 --- Lattices of alternating spin up and spin down --- p.64 / Chapter 7.2 --- Average propagation velocity --- p.67 / Chapter 7.3 --- Probability function of circular lattice --- p.69 / Chapter 7.4 --- Probability function of corresponding one-dimensional lattice --- p.71 / Chapter 8 --- Conclusion --- p.75 / Chapter A --- Generating function --- p.77 / Chapter B --- Discrete and integral transform --- p.78 / Chapter C --- Normal Distribution --- p.80 / Bibliography --- p.81
116

Aspectos da estrutura das partículas elementares / Aspects Structure Elementary Particles

Humberto de Menezes Franca 21 June 1979 (has links)
Mostra-se que a atribuição de uma estrutura não puntiforme para uma partícula segue da exigência de uma formulação consistente do movimento da mesma quando se leva em conta a reação da radiação. Apresenta-se um esquema que permite a determinação da estrutura das partículas elementares (ou qualquer outro sistema quântico), em termos de densidades de carga e magnetização, a partir do conhecimento dos seus fatores de forma eletromagnéticos. As novas conexões entre estas grandezas levam a uma descrição correta dos raios médios de carga. A densidade de matéria hadrônica é obtida, adotando o modelo de Chou-Yang, a partir dos dados experimentais de colisões próton-próton a altas energias. Verificamos que, se a parte imaginária de amplitude elástica for positiva, a densidade de matéria hadrônica é muito semelhante à densidade de magnetização no interior do prótin, o mesmo valendo para o nêutron. / It is shown how the attribution of a structure to a particle follows from the requirement of a consistent formulation of the motion of such a system when one takes into account the radiation reaction. A scheme is presented which allows us to determine the structure of an elementary particle (or any other quantum system) in terms of charge and magnetization densities, out of its electromagnetic Form Factors. The new connection between these quantities leads us to a correct description of the mean charge-radius. The hadronic matter density is obtained, by assuming the Chou-Yang model, out of the experimental data on pp collisions at high energies. It is shown that, under the hypothesis that the imaginary part of scattering amplitude be always positive, the hadronic matter density is very similar to the magnetization density within the proton. The same is true for the neutron.
117

Aspectos da estrutura das partículas elementares / Aspects Structure Elementary Particles

Franca, Humberto de Menezes 21 June 1979 (has links)
Mostra-se que a atribuição de uma estrutura não puntiforme para uma partícula segue da exigência de uma formulação consistente do movimento da mesma quando se leva em conta a reação da radiação. Apresenta-se um esquema que permite a determinação da estrutura das partículas elementares (ou qualquer outro sistema quântico), em termos de densidades de carga e magnetização, a partir do conhecimento dos seus fatores de forma eletromagnéticos. As novas conexões entre estas grandezas levam a uma descrição correta dos raios médios de carga. A densidade de matéria hadrônica é obtida, adotando o modelo de Chou-Yang, a partir dos dados experimentais de colisões próton-próton a altas energias. Verificamos que, se a parte imaginária de amplitude elástica for positiva, a densidade de matéria hadrônica é muito semelhante à densidade de magnetização no interior do prótin, o mesmo valendo para o nêutron. / It is shown how the attribution of a structure to a particle follows from the requirement of a consistent formulation of the motion of such a system when one takes into account the radiation reaction. A scheme is presented which allows us to determine the structure of an elementary particle (or any other quantum system) in terms of charge and magnetization densities, out of its electromagnetic Form Factors. The new connection between these quantities leads us to a correct description of the mean charge-radius. The hadronic matter density is obtained, by assuming the Chou-Yang model, out of the experimental data on pp collisions at high energies. It is shown that, under the hypothesis that the imaginary part of scattering amplitude be always positive, the hadronic matter density is very similar to the magnetization density within the proton. The same is true for the neutron.
118

Synergistically Engineered Hollow Particle And Molecular Amphiphile Systems For Oil Spill Remediation

January 2016 (has links)
Oil spill accidents represent an inherent occupational, environmental, economic, and community health disaster associated with the transformation of petroleum resources into products that help meet our world’s energy need. Dispersants are applied to break the oil spill into sufficiently small droplets and mitigate oil spill impacts by reducing the possibility of shoreline impact, lessening the impact on marine life and significantly increasing the oil-water interfacial area available for remediation processes. Existing dispersants are liquid solutions of surfactant in hydrocarbon solvents. There are several concerns with the existing dispersant systems including the large volume of hydrocarbon solvents introduced into the ecosystem. / Olasehinde Gbenro Owoseni
119

Dynamic pressure drop reduced by cones and spheres settling in a cylindrical conduit.

Langins, J. January 1969 (has links)
No description available.
120

Fine particle classification using dilute fluidized beds

Annapoorneswari, Rajasekharan Pillai, January 2007 (has links) (PDF)
Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 11, 2007) Includes bibliographical references (p. 50-51).

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