Дисертації: "Horizontal field"

1

Leighton, Feifei Zhang. "Numerical modelling of shallow flows with horizontal density variation." Thesis, University of Oxford, 2005. http://ora.ox.ac.uk/objects/uuid:2ea7400f-9b2c-4052-961e-84446f501822.

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A numerical model is presented of vertically homogeneous shallow flows with variable horizontal density. The governing equations represent mass and momentum conservation of a liquid-species mixture, and mass conservation of the species within a control volume. Here, the term species refers to material transported with the liquid flow. For example, when the species is taken to be suspended sediment, the model provides an idealised simulation of hyper-concentrated sediment-laden flows. The volumetric species concentration acts as an active scalar, allowing the species dynamics to influence the flow structure. The model can simulate flows driven by depth and density differences in the horizontal. The governing equations are written in a deviatoric, hyperbolic form to facilitate their solution by means of a Godunov-type finite volume scheme appropriate for flows containing sharp fronts. The deviatoric governing equations ensure that flux gradient and source terms are balanced (and there is no need for further numerical balancing). The numerical model is first verified for constant density cases, for which the governing equations reduce to the conventional coupled shallow water and species transport equations. Close agreement between numerical predictions and benchmark test solutions illustrate the model's ability to capture rapidly-varying flow features over uniform and non-uniform bathymetries. For variable-density cases, analytical steady-state solutions are derived for two simple cases, one with uniform bathymetry and the other with sinusoidal bathymetry. Detailed parameter studies are then undertaken to examine the effects of varying the initial density and depth in different regions. The shock-capturing scheme resolves all sharp features in the flow such as bore, shear waves, shock diamond like features, contact discontinuities and locally intense vortices. These interesting and novel nonlinear features are unique to variable density flows. The validated numerical model is applied to an idealised case of a hyperconcentrated sediment-laden debris-type flow along a tributary entering a river. The predicted evolution of the free surface flow field is qualitatively similar to observations of an actual debris flows into a river connected to the Upper Yangtze.

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2

Veenhuis, Robert S. "Matched field processing in shallow water using a small aperture horizontal line array." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA293673.

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Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, December 1994.
"December 1994." Thesis advisor(s): James H. Wilson. Includes bibliographical references. Also available on microform AND online.

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3

Budihardjo, Arifin 1968. "Near-zone electric field computation of a horizontal semi-infinite wire above earth." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278358.

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Asymptotic expressions are obtained for the electric field due to a current propagating on a horizontal semi-infinite wire above the earth. First, exact integral representations are derived for the electric field due to a current on a semi-infinite wire in a general multi-layered medium. The resulting integral expressions are then specialized for the problem of a semi-infinite wire above the earth. The resulting expressions involve a semi-infinite integration over an integrand containing the incomplete Lipschitz-Hankel integrals. The steepest descent technique is applied to the direct and reflected terms separately, thereby providing a far-zone approximation for the field (E α r⁻¹). A recurrence relationship is then developed which allows the r⁻² term in the asymptotic expansion to be computed from the previously computed r⁻¹ term. A numerical comparison between the following three methods is carried out: numerical integration, one-term (1/r) approximation, and two-term (1/r²) approximation. It is shown that two-term solution yields more accurate results than that of the one-term solution, especially when the problem of a finite length wire above the earth is considered. The two-term expansion provides accurate results for the fields when 0.1 λ < r < ∞ and it consumes much less computation time than the numerical integration solution.

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4

JUNIOR, ROBERTO DA FONSECA. "INSTANTANEOUS LIQUID VELOCITY FIELD MEASUREMENTS IN TWO-PHASE INTERMITTENT FLOW THROUGH HORIZONTAL AND INCLINED PIPES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15406@1.

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No presente trabalho foi realizado um estudo experimental sobre escoamento bifásico em regime intermitente através de tubos horizontais e de pequena inclinação, com o objetivo de determinação dos campos de velocidade instantâneos nas regiões a montante do nariz, a jusante da cauda das bolhas de gás, assim como na região do filme de líquido sob as bolhas. Foi implementada uma combinação de três técnicas ópticas não invasivas. Velocimetria por Imagem de Partículas bi-dimensional (Particle Image Velocimetry – PIV) foi utilizada para determinar os campos de velocidade instantâneos nas regiões de interesse, enquanto luz de fundo pulsada e sincronizada proveniente de uma matriz de LED’s vermelhos iluminava os contornos das bolhas aumentando o contraste das interfaces líquido-gás (Pulsed Shadow Technique – PST). Uma técnica baseada na fluorescência induzida por laser foi utilizada (Laser Induced Fluorescence - LIF) para separar a luz verde intensa proveniente do laser associado à técnica PIV. Os testes foram conduzidos em seção transparente tendo água e ar como fluidos de trabalho. Os resultados obtidos revelaram informações detalhadas sobre o escoamento de líquido no escoamento intermitente. Foram produzidos também resultados estatísticos de algumas variáveis globais do escoamento como, a velocidade e os comprimentos das bolhas e pistões de líquido, além da frequência de passagem desta estruturas do escoamento.
instantaneous liquid velocity fields at the film, nose and tail regions of slugs in horizontal and inclined two phase flow. To this end, a combination of three nonintrusive optical techniques was employed. Two-dimensional particle image velocimetry (PIV) was used to measure the instantaneous liquid velocity field at a meridional plane of the horizontal pipe test section, while a synchronized pulsed back lighting, provided by a matrix of red LED s, illuminated the bubble contours thereby enhancing contrast of the interfaces (Pulsed Shadow Technique - PST). A laser-induced fluorescence technique (LIF) was employed to separate the strong reflections coming from the gas-liquid interfaces produced by the green PIV laser, The tests were conducted on a specially built transparent pipe test section, using air and water as the working fluids. The velocity fields were obtained for flow regimes where the slugs were lightly aerated. The velocity field results in the nose, tail and film regions revealed valuable detailed information that helped to better understand the physics of the flow, besides contributing to the formation of a data bank for supporting the development of two-phase, horizontal slug flow simulations. The work conducted also provided statistical information on the main global variables that characterize the flow, such as, speed and length of gas bubbles and liquid slugs, and the frequency of passage of these structures.

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5

Rodrigues, Lázaro Luiz Fratoni. "Transmissão vertical e horizontal de parasitas usando autômatos celulares probabilísticos." Universidade Federal da Paraíba, 2011. http://tede.biblioteca.ufpb.br:8080/handle/tede/5782.

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Made available in DSpace on 2015-05-14T12:14:21Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2227394 bytes, checksum: 05a68822cdf04f42c1f50d5c368cac63 (MD5) Previous issue date: 2011-02-28
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
wide range of pathogens are transmitted by a combination of horizontal and vertical transmission; among these are microsporodians, helminths, bacteria and viruses of plants and animals, including important human pathogens such as HIV, HTLV-1, cytomegalovirus, several hepatitis viruses and herpes simplex [Proc. R. Soc. Lond. B 260: 321-327]. In this work, the vertical parasite spreading from parent to offspring and horizontal transmission through infection in a population of moving individuals are discussed using a probabilistic cellular automata implemented on a square lattice. In our model, we generalize the automata proposed in [J. Phys. A : Math. Gen. 27: 1585-1597] to include the vertical transmission. The local rule consists of two subrules: the first one, applied synchronously, models infection, birth and death processes; the second, applied sequentially, describes the motion of individuals. In this model, endemic states may occur (susceptible and infected individuals coexisting) or a disease-free state (without infected). It is worth mentionins that a state in which the entire population becomes infective is possible in the case of perfect vertical transmission, i.e. infected parents give birth only to infected offspring. Moreover, the stability of these states may be analised using a mean-field approximation or grafically verified from the numerical simulations.
Uma ampla faixa de patógenos são propagados por uma combinação de transmissão horizontal e vertical, dentre os quais podemos destacar: microesporídeos, helmintos, bactérias, fungos e vírus de plantas e animais, incluindo importantes microorganismos parasitas de humanos como o HIV, HTLV-1, cytomegalovírus, vários tipos de hepatite e herpes simples [Proc. R. Soc. Lond. B 260: 321-327 (1995)]. Neste trabalho, a transmissão vertical (infecção do genitor para os filhos) e a transmissão horizontal (infecção por contágio) numa população de indivíduos em movimento são discutidos usando um autômato celular probabilístico implementado numa rede quadrada. Em tal modelo, generalizamos o autômato proposto em [J. Phys. A : Math. Gen. 27: 1585-1597 (1994)] para incluir a transmissão vertical. A regra local consiste de duas subregras: a primeira modela de maneira sincronizada os nascimentos, as mortes e as infecções; já a segunda, aplicada sequencialmente, descreve o movimento dos indivíduos. Neste modelo é possível um estado endêmico (suscetíveis coexistindo com infectados) ou um estado livre de doenças (sem infectados). Salienta-se que um estado em que toda a população torna-se infectada é possível no caso de transmissão vertical perfeita, i.e. pais infectados possuem apenas descendentes infectados. Inclusive, a estabilidade destes estados pode ser analizada na aproximação de campo médio para este modelo, ou verificada através dos gráficos dos resultados das simulações numéricas.

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6

Dong, Danan. "The horizontal velocity field in southern California from a combination of terrestrial and space-geodetic data." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/52979.

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7

Achinivu, Ochi I. "Field application of an interpretation method of downhole temperature and pressure data for detecting water entry in horizontal/highly inclined gas wells." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2355.

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8

Carrera, Sandra Garcés. "Virulence of Mayetiola destructor (Say) field populations in the Great Plains and levanase/inulase-like genes in the Hessian fly genome." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/16873.

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Doctor of Philosophy
Department of Entomology
Ming-Shun Chen
C. Michael Smith
The Hessian fly, Mayetiola destructor (Say), is a major pest of wheat, and is controlled mainly through deploying fly-resistant wheat cultivars. This study investigated five M. destructor populations collected from Texas, Louisiana, and Oklahoma, where infestation by Hessian fly has been high in recent years. Eight resistance genes including H12, H13, H17, H18, H22, H25, H26, and Hdic, were found to be highly effective against all tested M. destructor populations in this region, conferring resistance to 80% or more of plants containing one of these resistant genes. The frequency of biotypes virulent to resistant genes ranged from 0 to 45%. A logistic regression model was established to predict biotype frequencies based on the correlation between the percentages of susceptible plants obtained in a virulence test. In addition to the virulence test, the log-odds of virulent biotype frequencies were determined by a traditional approach to predict the logistic regression model. Characterization of a bacterial artificial chromosome (BAC) clone identified a gene encoding a protein with sequence similarity to bacterial levanases. Blast searching with the levanase-like protein identified 14 levanase/inulase-like genes or gene fragments. In this study, we determined the expression levels of these genes in different developmental stages and different tissues of 3-d old larvae of M. destructor. Sequence analysis revealed that six genes encode full length proteins, three were truncated at the 5’ end, and five truncated at the 3’ end. Sequences of putative proteins showed approximately 42% similarities to bacterial levanases or inulases, and 36% similarity to fungal levanases or inulases. No sequence similarities were found with any known animal or plant proteins. Comparative analysis of sequences among 14 levanase/inulase-like genes revealed that positions for intron/exon boundaries are conserved among different genes even though the length of each intron and exon varied among different genes. The expression patterns of the levanase/inulase-like genes were different among developmental stages and larval tissues of M. destructor. Interestingly, three genes presented alternative splicing bands in different developmental stages, and two genes exhibited splicing bands in different tissues of 3 d old M. destructor. This study would be useful for future studies of the characterization and function of levanase/inulase-like genes of these enzymes in plant-insect interactions.

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9

Rivero, Diaz Jose Antonio. "Experimental studies of steam and steam-propane injection using a novel smart horizontal producer to enhance oil production in the San Ardo field." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5753.

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A 16ÃÂ16ÃÂ5.6 in. scaled, three-dimensional, physical model of a quarter of a 9-spot pattern was constructed to study the application of two processes designed to improve the efficiency of steam injection. The first process to be tested is the use of propane as a steam additive with the purpose of increasing recovery and accelerating oil production. The second process involves the use of a novel production configuration that makes use of a vertical injector and a smart horizontal producer in an attempt to mitigate the effects of steam override. The experimental model was scaled using the conditions in the San Ardo field in California and crude oil from the same field was used for the tests. Superheated steam at 190 Ã¢ÂÂ 200ÃÂºC was injected at 48 cm3/min (cold water equivalent) while maintaining the flowing pressures in the production wells at 50 psig. Liquid samples from each producer in the model were collected and treated to break emulsion and analyzed to determine water and oil volumes. Two different production configurations were tested: (1) a vertical well system with a vertical injector and three vertical producers and (2) a vertical injector-smart horizontal well system that consisted of a vertical injector and a smart horizontal producer divided into three sections. Runs were conducted using pure steam injection and steam-propane injection in the two well configurations. Experimental results indicated the following. First, for the vertical configuration, the addition of propane accelerated oil production by 53% and increased ultimate recovery by an additional 7% of the original oil in place when compared to pure steam injection. Second, the implementation of the smart horizontal system increased ultimate oil recovery when compared to the recovery obtained by employing the conventional vertical well system (49% versus 42% of the OOIP).

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10

McPhillips, Kenneth J. "Far field shallow water horizontal wave number estimation given a linear towed array using fast maximum likelihood, matrix pencil, and subspace fitting techniques /." View online ; access limited to URI, 2007. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3276997.

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11

Hard, Louise. "How is leadership understood and enacted within the field of early childhood education and care." Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16213/1/Louise_Hard_Thesis.pdf.

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The field of Early Childhood Education and Care (ECEC) traditionally encompasses care and education for children aged from birth to eight years. In this study, the focus is specifically on the field that provides services for children in prior to school settings, that being the birth to five sector. This sector is highly feminised and has emerged over the last century from philanthropic roots. Despite considerable work into leadership in other areas, until recent times, attention to aspects of leadership has been limited within the ECEC field and much of the research undertaken has focused heavily on centre-based leadership. This study investigated how personnel, from a range of services, understand and enact leadership. In terms of data analysis it draws heavily on symbolic interactionism as a methodological tool and engages standpoint feminist theory to inform the analytical process. Data were gathered from semi-structured interviews with twenty-six participants who also identified artefacts, which they considered influenced and supported their understandings of leadership. In addition, two focus groups were conducted to explore themes emerging from early analysis of the data. Findings indicate two categories, which emerge as relevant to how leadership is understood and enacted by participants. The first of these is the concept of interpreted professional identity, which reflects participants' interpretations of who they are as early childhood professionals informed by their own views and the views of others. How individuals interpret their sense of self (manifest in their professional identity) is influential in the secondary category, which is interpreted leadership capacity. This category reflects participants' leadership activity or inactivity. The analysis reflects a complex interplay between how participants interpret their professional sense of self (interpreted professional identity) and their capacity and willingness to enact leadership (interpreted leadership capacity). Individuals in the formation of their professional identity interpret factors, both internal to the ECEC field and external (through social expectations). The culture of the ECEC field (internal factors) includes competing elements such as a discourse of niceness juxtaposed against examples of horizontal violence. Factors external to the field suggest there are lingering social associations between heroic male images and leadership, which make women as leaders problematic. Within a highly feminised field such as ECEC, this study brings new perspectives to understandings of leadership and its enactment.

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12

Hard, Louise. "How is leadership understood and enacted within the field of early childhood education and care." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16213/.

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The field of Early Childhood Education and Care (ECEC) traditionally encompasses care and education for children aged from birth to eight years. In this study, the focus is specifically on the field that provides services for children in prior to school settings, that being the birth to five sector. This sector is highly feminised and has emerged over the last century from philanthropic roots. Despite considerable work into leadership in other areas, until recent times, attention to aspects of leadership has been limited within the ECEC field and much of the research undertaken has focused heavily on centre-based leadership. This study investigated how personnel, from a range of services, understand and enact leadership. In terms of data analysis it draws heavily on symbolic interactionism as a methodological tool and engages standpoint feminist theory to inform the analytical process. Data were gathered from semi-structured interviews with twenty-six participants who also identified artefacts, which they considered influenced and supported their understandings of leadership. In addition, two focus groups were conducted to explore themes emerging from early analysis of the data. Findings indicate two categories, which emerge as relevant to how leadership is understood and enacted by participants. The first of these is the concept of interpreted professional identity, which reflects participants' interpretations of who they are as early childhood professionals informed by their own views and the views of others. How individuals interpret their sense of self (manifest in their professional identity) is influential in the secondary category, which is interpreted leadership capacity. This category reflects participants' leadership activity or inactivity. The analysis reflects a complex interplay between how participants interpret their professional sense of self (interpreted professional identity) and their capacity and willingness to enact leadership (interpreted leadership capacity). Individuals in the formation of their professional identity interpret factors, both internal to the ECEC field and external (through social expectations). The culture of the ECEC field (internal factors) includes competing elements such as a discourse of niceness juxtaposed against examples of horizontal violence. Factors external to the field suggest there are lingering social associations between heroic male images and leadership, which make women as leaders problematic. Within a highly feminised field such as ECEC, this study brings new perspectives to understandings of leadership and its enactment.

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13

Park, YoongSoo. "The development and field testing of an instrument for measuring citizens' attitudes toward public school funding in terms of equity, adequacy, and accountability." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1268147159.

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14

Faro, Vitor Pereira. "Carregamento lateral em fundações profundas associadas a solos tratados : concepção, provas de carga e diretrizes de projeto." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/100167.

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As obras de engenharia atuais envolvem unidades estruturais de grande porte cujo projeto e execução devem ser cuidadosamente observados. Devido à complexidade das cargas e solicitações estruturais, as metodologias de projeto devem atender a necessidades específicas. A variabilidade geotécnica associada à diversidade de carregamentos, impõe a necessidade de desenvolvimento de metodologias aplicadas especificamente a projetos de fundações que serão sujeitas a carregamentos laterais, tais como pontes, obras portuárias, torres de linhas de transmissão, aerogeradores (onshore e offshore) e plataformas (offshore e nearshore) de exploração de petróleo e gás natural. Existem alguns métodos relatados na literatura geotécnica para projeto de fundações submetidas a esforços horizontais. Nenhum destes métodos considera uma solução baseada no simples reforço, através de técnicas de cimentação, dos solos na sua camada superficial, radial à estaca. Dessa forma, procura-se na presente pesquisa estudar o comportamento de fundações profundas com reforço do solo na sua camada superficial, sujeitas a carregamentos horizontais. São apresentadas diretrizes de projeto, estabelecendo-se ainda um modelo de previsão da capacidade de carga de fundações profundas submetidas a este tipo de carregamentos. Ensaios em campo experimental e simulações numéricas tridimensionais, usando o Método dos Elementos Finitos foram realizados, por forma a se obter uma melhor compreensão do comportamento de estacas carregadas lateralmente. Considerando o diâmetro da estaca (D) e a sua profundidade (L), no campo experimental, foram definidas razões L/D representando o comportamento de estacas rígidas e flexíveis. Diversos ensaios de carregamento horizontal foram realizados para estas relações L/D, em solo natural e com solo melhorado radial às estacas. As análises numéricas consistiram numa análise paramétrica onde foram variados parâmetros geométricos (da estaca e do solo tratado) e geotécnicos, necessários à caracterização dos materiais no modelo utilizado, o de Mohr-Coulomb. O modelo de previsão proposto foi obtido com base na análise dos resultados de simulações numéricas usando o software ABAQUS®, validados com provas de cargas no campo experimental. É também de salientar que nesta pesquisa apenas será considerada a ruptura geotécnica, pelo que é assumido que as estacas têm comportamento elástico. Do estudo realizado pode-se concluir que o uso de uma camada superficial de solo tratado radial à estaca melhora significativamente o desempenho do sistema, aumentando a sua capacidade de carga e diminuindo a sua deformação, mostrando ser uma ótima e promissora alternativa para fundações profundas sujeitas a carregamentos horizontais.
Current engineering works typically envolve large structural units whose design and implementation should be closely observed. Due to the complexity of the loads and structural needs, the design methodologies should comply specific requirements. The geotechnical variability combined with the loads diversity imposes the need to develop methodologies applied specifically to projects whose foundations will be laterally loaded, like bridges, harbors, transmission line towers, onshore and offshore wind turbines, among others. There are several methods reported in geotechnical literature to design piles that will be subjected to horizontal loads. However, none of these methods consider a solution based on a simple soil reinforcement using cementation techniques, in a superficial layer, radial to pile. The main goal of this research is to study the behavior of deep foundations with a reinforced soil system, subjected to lateral loads. Design guidelines are presented, leading to a model that predicts the ultimate load capacity of deep foundations subjected to these types of efforts. Field tests and tridimensional numerical simulations using the Finite Element Method were performed in order to achieve a better understanding of the behaviour of laterally loaded piles. Considering the pile diameter (D) and its depth (L), different L/D ratio were defined, corresponding to rigid and flexible piles. Using these L/D ratios, in both natural and reinforced soils, numerical and field tests were performed to provide experimental evidences of its behaviour. Numerical tests consisted in a parametric analysis where different geometric (pile and treated soil) and geotechnical parameters, necessaries to the Mohr-Coulomb model, have been modified. The proposed prediction model is based on the analysis of the numerical simulations results, using ABAQUS® software, validated with the field tests. It is important to point that in this study only geotechnical rupture is considered. Therefore it is assumed that piles have elastic behaviour. Has been concluded that the use of a superficial treated layer, radial to pile, considerably improves the system performance, increasing the lateral load capacity and decreasing their deformation, showing that this technique could be a promising solution to deep foundations subjected to horizontal loads.

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15

Ozkan, Erdal. "Performance of horizontal wells /." Access abstract and link to full text, 1988. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8825498.

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16

Kracík, Petr. "Hodnocení přestupu tepla na skrápěném trubkovém svazku." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-240776.

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Sprinkled tube bundles with a thin liquid film flowing over them are used in various technology processes where it is necessary to separate the vapour and liquid phases quickly and efficiently. The process occurs predominantly at low temperatures with a corresponding decrease of pressure around the tube bundle. Such a technology is represented for instance by an evaporator at absorption units or an evaporator for sea water desalination. In ideal conditions water boils at the whole surface of an exchanger, but in practice it must be considered that in original spots of contact between water and the exchanger wall the water will not boil at the tubes' surface but the cooling liquid will merely be heated-up. The presented dissertation thesis focuses on this issue. The objective of the thesis was to determine the heat transfer coefficient at the surface of sprinkled tube bundles of various geometries at atmospheric pressure as well as low pressure. For this purpose experiments have been carried out at tube bundles consisting of copper tubes of 12,0 mm diameter placed horizontally one above another that were heated by water. Three types of tubes (smooth, sandblasted and grooved) of four various pitches (15,0 to 30,0 mm by 5,0 mm increments) have been tested. Simultaneously individual bundles' geometries consisted of 4, 6, 8 and 10 tubes with identical surface finish. Based on the conducted experiments the mathematical model of heat transfer that involves mainly analogy criteria has been made more accurate. A temperature field at the sprinkled tube bundle surface has been scanned by a thermographic camera during the performed experiments. Influence of geometry and tube surface finish on flow mode and consequently also on heat transfer has been assessed in accordance with the compiled methodology.

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17

Davenport, Christopher M. "Neural circuitry of retinal receptive fields in primate /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10652.

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18

Kim, Yoon Duk. "Transverse Stiffener Requirements in Straight and Horizontally Curved Steel I-Girders." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4802.

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Recent research studies have confirmed that curved I-girders are capable of developing substantial shear postbuckling resistance due to tension field action and have demonstrated that the AASHTO LRFD equations for the tension field resistance in straight I-girders may be applied to curved I-girders within specific limits. However, the corresponding demands on intermediate transverse stiffeners in curved I-girders are still largely unknown. Furthermore, a number of prior research studies have demonstrated that transverse stiffeners in straight I-girders are loaded predominantly by bending induced by their restraint of web lateral deflections at the shear strength limit state, not by in-plane tension field forces. This is at odds with present Specification approaches for the design of transverse stiffeners, which are based on (1) providing sufficient stiffener bending rigidity only to develop the shear buckling strength of the web and (2) providing sufficient stiffener area to resist the in-plane tension field forces. In this research, the behavior of one- and two-sided intermediate transverse stiffeners in straight and horizontally curved steel I-girders is investigated by refined full nonlinear finite element analysis. Variations in stiffener rigidity, panel aspect ratio, panel slenderness, and stiffener type are considered. New recommendations for design of transverse stiffeners in straight and curved I-girder bridges are developed by combining the solutions from the above FEA studies with the results from prior research.

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19

Orr, Andrew McLean White. "Computational techniques for evaluating extremely low frequency electromagnetic fields produced by a horizontal electric dipole in seawater." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326222.

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20

Plucinski, Matthew Paul Mathematics &amp Statistics Australian Defence Force Academy UNSW. "The investigation of factors governing ignition and development of fires in heathland vegetation." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Mathematics and Statistics, 2003. http://handle.unsw.edu.au/1959.4/38702.

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Heathlands typically experience regimes consisting of frequent and intense fires. These fire regimes play important roles in the lifecycles and population dynamics of all species in these communities. Prescribed fire is commonly applied to heathlands to minimise the risk of wildfires as well as to promote biodiversity. Ignitions in heathlands tend to either be unsustainable, or quickly develop into rapidly spreading intense fires. This presents a major problem for the application of prescribed fire and is the primary focus of this thesis. Heathland ignition has been investigated in three sections; litter ignition; vertical development of fire into the shrub layer; and horizontal spread through the shrub layer. These were studied in laboratory experiments using miniature versions of field fuels. Ignition success in litter layers was related to the dead fuel moisture content. Litter type, ignition source, and presence of wind were found to affect the range of ignitable fuel moisture contents of a litter bed. The effect of litter type was best explained by density. Dense litter beds required drier conditions for ignition than low density litter beds. The vertical development of fire into shrubs was mostly dependent on live fuel moisture content, but crown base height, presence of wind, ignition source, shrub height and the percentage of dead elevated fuel were also important. Horizontal spread of fires through shrub layers was most affected by the presence of a litter layer, with nearly all ignitions successful when there was an underlying litter fire. Fire spread would only occur in shrubs without a litter layer when the shrub layer was dense and dry, or had a substantial dead fuel component. Spread was more likely to be sustained when there was wind. Models predicting the moisture content of dead fuels were tested in heathlands, and as would be expected those that can be calibrated for different fuel types were found to have the best performance. Fuel moisture content and fuel load models were reviewed for heathlands, and a number of recommendations for future research were made.

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21

Davoust, Laurent. "Convection naturelle MHD dans une cavité horizontale élancée." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0139.

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Lors de la croissance des monocristaux semi-conducteurs a partir d'un bain fondu, la convection naturelle gouverne de maniere determinante les transferts de masse et de chaleur. Comme la micro-gravite, l'imposition d'un champ magnetique permanent sur le bain - electro-conducteur - est un moyen de stabiliser, de reorganiser l'ecoulement de convection naturelle et, finalement, de le freiner afin de s'approcher au mieux des conditions ideales d'un transport diffusif des especes chimiques. Dans un premier temps, une synthese des connaissances acquises sur les ecoulements thermogravitaires, magnetohydrodynamiques (mhd) ou non, est presentee. Puis, sur la base du dispositif experimental mascot (magnetic stabilisation of convection and turbulence), les phenomenes qui gouvernent l'ecoulement thermogravitaire mhd du mercure dans une cavite cylindrique horizontale elancee, soumise a la fois a un champ magnetique uniforme et a un gradient de temperature horizontal, sont mis en evidence puis interpretes a l'aide de la mhd. Dans cette configuration particuliere, les couches de hartmann demeurent electriquement inactives. L'inertie n'influence l'ecoulement que localement (aux extremites de la cavite), et surtout dans le cas ou la convection est intense (a grand nombre de grashoff). Ailleurs, le couplage entre courants electriques induits et distribution de temperature est illustre par l'equilibre entre le rotationnel de la force de laplace et le rotationnel de la force de flottabilite. Cet equilibre pilote l'ecoulement pour un nombre de rayleigh modifie, dit effectif, suffisamment faible. Une simulation numerique 3-d aux elements finis de cet ecoulement (laminaire) apporte une confirmation satisfaisante de ces resultats experimentaux. Ce memoire est l'etude de la transition de cet ecoulement vers la turbulence, a l'aide de l'experience mascot. Trois ondes oscillantes progressives ou stationnaires sont clairement identifiees pendant la transition. Si la convention est intense, ces ondes interagissent avec des instabilites stationnaires evoluant faiblement dans le temps. Le couplage non-lineaire associe au terme de convection dans l'equation de l'energie engendre une bifurcation sous-critique. Puis, si le regime d'ecoulement est faiblement convectif, le chaos survient a la suite d'une bifurcation supercritique de hopf. Ces resultats ouvrent des perspectives de developpement technologique pour le procede bridgman de croissance cristalline. Et plus generalement, ce progres dans la comprehension de la convection naturelle mhd pourrait s'appliquer dans d'autres situations: en genie metallurgique ou dans les couvertures tritigenes du futur reacteur de fusion thermonucleaire

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22

Гедзик, Н. М. "Удосконалення технології підвищення газовилучення з родовищ із низькопроникними теригенними колекторами". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2016. http://elar.nung.edu.ua/handle/123456789/4779.

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Дисертація присвячена удосконаленню технології підвищення газовилучення та поточних відборів з родовищ із низькопроникними теригенними колекторами. У роботі експериментально встановлено вплив температури, тиску і проникності піщаних колекторів на величину питомого об’єму адсорбованого газу та отримано відповідну емпіричну залежність. Експериментально визначено відносну адсорбційну здатність метану, азоту та діоксиду вуглецю на поверхні ущільнених пісковиків та обгрунтовано напрямки підвищення коефіцієнта газовилучення за рахунок інтенсифікації видобутку адсорбованого газу шляхом запомповування невуглеводневих заміщувальних агентів. Досліджено вплив тиску та методу запомповування невуглеводневих заміщувальних агентів на коефіцієнт кінцевого газовилучення. За результатами комп’ютерного гідродинамічного моделювання у програмному середовищі Eclipse 300 оцінено оптимальні параметри профілів свердловин і тріщин гідравлічного розриву пласта за технологічними та економічними критеріями. Експериментально встановлено вплив адсорбційно-десорбційних процесів на характер кривої зведеного пластового тиску від накопиченого видобутку газу. Уточнено рівняння матеріального балансу при газовому режимі розробки шляхом урахування адсорбційно-десорбційних процесів. На основі отриманих рівнянь уточнено відповідні методики прогнозування технологічних показників розробки газових родовищ з низькопроникними колекторами вертикальними та горизонтальними свердловинами. Узагальнено отримані результати та наведено рекомендації щодо практичного використання та подальшого промислового впровадження розроблених техніко-технологічних рішень.
Диссертация посвящена совершенствованию технологии увеличения газоотдачи и текущих отборов из месторождений природных газов с низкопроницаемыми терригенными коллекторами. По результатам работы впервые экспериментально установлено влияние температуры, давления и проницаемости песчаных пород-коллекторов на способность адсорбировать метан. Получена аналитическая зависимость, которая позволяет оценить количество адсорбированного газа в зависимости от проницаемости коллектора, давления и температуры. Экспериментально определено относительную адсорбционную способность метана, азота и диоксида углерода на поверхности уплотненных песчаников и обоснованы направления повышения коэффициента газоотдачи за счет интенсификации добычи адсорбированного газа путем нагнетания неуглеводородных заместительной агентов. Исследовано влияние давления и метода нагнетания неуглеводородных заместительных агентов на коэффициент конечной газоотдачи месторождений природных газов с низкопористых низкопроницаемых коллекторами и обоснованно физический смысл процессов, которые при этом проходят. По результатам компьютерного гидродинамического моделирования проведена оценка оптимальных параметров стволов скважин и трещин гидравлического разрыва пласта исходя из их технико-технологической и экономической оптимизации с использованием генетических алгоритмов. Оценено значение чистого дисконтированного денежного дохода в зависимости от параметров скважины, трещин гидравлического разрыва пласта и проницаемости коллектора. Обоснованы рекомендации по бурению горизонтальных скважин в низкопроницаемых коллекторах и проведения в них гидравлического разрыва пласта. После анализа промышленных данных и результатов собственных лабораторных исследований обоснована целесообразность учета адсорбционно-десорбцийних процессов при разработке месторождений природных газов с низкопористыми низкопроницаемыми коллекторами. Экспериментально установлено влияние адсорбционно-десорбцийних процессов на характер кривой сводного пластового давления от накопленной добычи газа. Уточнено уравнение материального баланса для газового месторождения при газовом режиме разработки путем учета адсорбционно-десорбцийних процессов при разработке вертикальными и горизонтальными скважинами на истощение и при нагнетании неуглеводородных заместительной агентов по обоснованным технологиям. На основе полученных уравнений уточнены соответствующие методики прогнозирования технологических показателей разработки. Разработаны уравнения и методики апробированы для условий гипотетического газового месторождения. Проведено сравнение полученных результатов с мировым опытом и сделаны соответствующие выводы. Приведены обобщения и рекомендации по практическому использования и промышленному внедрению предлагаемых технико-технологических решений.
The thesis is devoted to improving the enhanced gas recovery technology and current gas production from the fields with low-permeable terrigenous reservoirs. The paper experimentally established the effect of temperature, pressure and permeability of sand reservoirs on the value of specific volume of adsorbed gas and appropriate empirical relationship was obtained. The relative adsorption of methane, nitrogen and carbon dioxide on the surface of sand packed model was experimentally determined and the directions for enhanced gas recovery factor by gas desorption intensification using non-hydrocarbon displacement agents injection were grounded. The influence of pressure and method of non-hydrocarbon displacement agents injection on ultimate gas recovery factor was determined. As a result of hydrodynamic computer simulation using Eclipse 300 software the optimal parameters of wells profiles and hydraulic fractures were evaluated based on technological and economic criteria. The impact of adsorption-desorption processes on the dynamics of the curve of reduced reservoir pressure from cumulative gas production was experimentally established. The material balance equation under gas drive was specified by taking into account adsorption-desorption processes. On the basis of these equations the calculation methods were specified for predicting the technological parameters of the natural gas fields with low-permeable reservoirs development by vertical and horizontal wells. Obtained results were summarized and recommendations for practical implementation and commercialization of elaborated technical and technological solutions were suggested.

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23

Predrag, Pecev. "Развој алгоритма и система за дедуктивну предикцију и анализу кретања кошаркашких судија". Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=104240&source=NDLTD&language=en.

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Докторска дисертација припада области информационих система, са јасним акцентом на употребу неуронских мрежа за решавање проблема вишеструких зависних временских серија који је у овом докторату дефинисан.Основни циљ дисертације је креирање система у форми едукативног софтвера путем којег ће се обучавати младе кошаркашке судијеЈедан од кључих елемената овог доктората јесте симулација хоризонталног видног поља на основу којег се утврђује да ли је резоновано кретање кошаркашких судија било адекватно или није. Стога развијени софтвер поседује споменуту едукативну примену.Како би се реализовао споменути софтвер спроведено је истраживање које је обухватило обучавање великог броја традиционалних вишеслојних перцептрона као и формирање посебне LTR – MDTS структуре неуронске мреже за коју се сматра да је погодна за решавање постојећег проблема. За реализацију симулације хоризонталног видног поља разматрано је више алгоритама из области рачунарске графике а Sweep and Prune алгоритам је парцијално пружио основу за развијени и тренутно имплементирани алгоритам.
Doktorska disertacija pripada oblasti informacionih sistema, sa jasnim akcentom na upotrebu neuronskih mreža za rešavanje problema višestrukih zavisnih vremenskih serija koji je u ovom doktoratu definisan.Osnovni cilj disertacije je kreiranje sistema u formi edukativnog softvera putem kojeg će se obučavati mlade košarkaške sudijeJedan od ključih elemenata ovog doktorata jeste simulacija horizontalnog vidnog polja na osnovu kojeg se utvrđuje da li je rezonovano kretanje košarkaških sudija bilo adekvatno ili nije. Stoga razvijeni softver poseduje spomenutu edukativnu primenu.Kako bi se realizovao spomenuti softver sprovedeno je istraživanje koje je obuhvatilo obučavanje velikog broja tradicionalnih višeslojnih perceptrona kao i formiranje posebne LTR – MDTS strukture neuronske mreže za koju se smatra da je pogodna za rešavanje postojećeg problema. Za realizaciju simulacije horizontalnog vidnog polja razmatrano je više algoritama iz oblasti računarske grafike a Sweep and Prune algoritam je parcijalno pružio osnovu za razvijeni i trenutno implementirani algoritam.
Doctoral dissertation belongs to the field of information systems, with a clear emphasis on the use of neural networks for solving the problem of multiple dependent time series, which is defined in this doctorate. The main objective of the thesis is to create a system in the form of educational software that will be used druring the training of young basketball referees.One of the key elements of this doctorate is a simulation of a horizontal field of vision on the basis of which it is determined whether the movement of reasoned basketball referees was adequate or not. Therefore developed software has aforementioned educational use. In order to realize the aforementioned software, a research was conducted that included training of a large number of traditional multilayer perceptron neural networks and the formation of special LTR - MDTS neural network structure which is considered to be suitable for solving the presented problem. For the realization of the simulation of the horizontal field of vision a large number of algorithms in the field of computer graphis was considered and Sweep and Prune algorithm partially provided the basis for the developed and currently implemented algorithm.

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Almeida, Luciane Infantini da Rosa. "Razões, sentimentos e projetos profissionais: experiência dos vestibulandosas (Vitória, ES, 2009 - 2010)." Universidade do Estado do Rio de Janeiro, 2010. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2755.

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Dar nitidez aos sentimentos e razões que emergem das experiências dos vestibulandos de Vitória-ES, entre 2009-2010, e que os movem em direção a seus projetos profissionais é objetivo deste trabalho. A noção de projeto aqui utilizada (VELHO, 1999) afasta-se da clássica compreensão liberal do ser humano, autônomo, livre e único, responsável por seus sucessos e fracassos, subjacente a estudos sobre escolha profissional. A ideia proposta é que campo de experiências dos sujeitos marca seus projetos profissionais, mas que suas condutas deliberadas, não necessariamente racionais, expõem certas expectativas de vida, quaisquer que sejam as posições sociais desses sujeitos. Para o exame dessas expectativas, esses sujeitos foram vistos em suas relações sociais - nas interseções de classes, gênero, de cor da pele, de gerações, etc. Reconheceu-se, ainda, que razões e sentimentos (WILLIAMS, 1969), também forjam projetos profissionais de sujeitos sob diversas condições sociais e apesar delas. Por considerar que esses projetos portam manifestações humanas, nem sempre perceptíveis e tantas vezes encobertas, a metáfora do rizoma (DELEUZE; GUATTARI, 2004), foi de utilidade metodológica. Alguns indícios (GINZBURG, 2007), sugeriram caminhos de pesquisa e alguns dos significados aos sujeitos para que esses projetos pudessem ser detectados. A perspectiva da longa duração histórica e dos tempos múltiplos presidiu o exame de trajetórias selecionadas de um conjunto de sujeitos pesquisados entre os anos 2009-2010, o que favoreceu a percepção de continuidades históricas, mas também a ocorrência de mudanças de certas tendências sociais. Dois cursos de pré-vestibular, um público e um privado, em Vitória, ES, nessa conjuntura, mostraram um pouco da pluralidade de expectativas de diferentes jovens - pobres, de classes média e alta, homens e mulheres, brancos, negros e pardos, mais novos e mais velhos em relação ao ensino superior presente em seus projetos profissionais. Razões e sentimentos que os movem e que se movem, nem sempre examinados em estudos sobre a matéria, foram expostos. Contribuições de Elias (1990), de R. Williams (1969), de Bourdieu (2003, 2009), de E. P. Thompson (2002), de Löwy (1990), entre outros, apoiaram evidências de que as relações indivíduo e sociedade, sempre plurais e complexas, expressam apenas partes de seus sentidos civilizadores. Para reduzir incertezas, recorreu-se a dados macrossociais e microssociais (REVEL, 1998). Entrevistas com tais jovens e coordenadores de seus cursos, observações advindas de dinâmica de grupo e, também, exame de publicações oficiais, de periódicos de divulgação de matéria sobre vestibular, entre 2009-2010, situaram um trato de escalas analíticas de difícil exercício. Para além das relações de classes, gênero, cor da pele, geração etc., pode-se concluir que esses sujeitos, por razões e sentimentos variados, com seus projetos profissionais, tanto se deslocam de suas posições sociais de origem como as mantêm, mas todos, em suas novas experiências e de diferentes modos, também se preparam para atuar sobre os sentidos civilizadores de seu tempo.
Provide clarity to the feelings and reasons that emerge from the experiences of the students in Vitória-ES, between 2009-2010, and what move them toward their professional projects is the goal of this work. The notion of design used here (Velho, 1999) differs from the classical liberal understanding of human being, autonomous, free and unique, responsible for their successes and failures, underlie to studies on "career choice". The proposed idea is that the field experiences of the subjects mark their professional projects, but their deliberate conduct, not necessarily rational, expose certain life expectations, whatever is the social position of these individuals. To test these expectations, these subjects were seen in their social relations on the intersections of class, gender, ethnicity, generations, etc. It was recognized also that the reasons and feelings (WILLIAMS, 1969) also forge professional projects of subjects under different social conditions and in spite of them. Considering that these projects carry human manifestations not always visible, often covered, the metaphor of "rhizome" (DELEUZE; GUATTARI, 2004) was useful as methodology. Evidences (GINZBURG, 2007) suggested research paths and some of the meanings attributed by those subject to these projects could be detected. The prospect of long-term historical and multiple times chaired the examination of trajectories of a selected group of subjects studied between the years 2009-2010, which favored the perception of historical continuities, but also the occurrence of certain changes in social trends. Two pre-university courses, one public and one private, in Vitória, ES, at this juncture, showed a bit of a plurality of different expectations of young people - poor, middle and upper classes, men and women, whites, blacks and browns, younger and older in relation to high school - present in their professional projects. Reasons and feelings that move them and that move is not always considered in studies on the subject, were exposed. Contributions of Elias (1990), Williams (1969), Bourdieu (2003, 2009), E. P. Thompson (2002), Löwy (1990), among others, supported evidences that the relation between individual and society, always plural and complex, express only parts of their civilizing senses. To reduce uncertainties, it was used macro and micro data (Revel, 1998). Interviews with these teenagers and advisers, observations from group dynamics and also examination of official publications, periodicals to disseminate material on vestibular, between 2009-2010, were located a tract of analytical scales difficult to exercise. Apart from relations of class, gender, skin color, generation, etc., is possible to conclude that these subjects, for reasons and various feelings, with their professional projects, move are not from their social origin, but all of them, in their new experiences and different ways, also prepare themselves to act on the senses civilizing of his time.

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25

Capri, Marcio André Lopes. "Aspectos não perturbativos das teorias de Yang-Mills no calibre abeliano maximal." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=1373.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Neste tese, estudamos os efeitos não perturbativos associados à presença do horizonte de Gribov e à condensação de operadores locais de dimensão dois, numa teoria de Yang-Mills euclidiana em SU(2), quantizada no calibre abeliano maximal. Estes efeitos são introduzidos de modo a preservar as propriedades de renormalizabilidade e localidade da teoria, e refletem-se diretamente no comportamento dos propagadores. A comparação com os dados da rede indicam um bom acordo qualitativo.
In this, we study the nonperturbative effects associated to the presence of the horizon and to the condensation of local dimension two operators in an Eucledean SU(2)Yang-Mills theory quantized in the maximal Abelian gauge. Such effects are introduced in a way to preserve the properties of renormalizability and locality of the theory. The comparison with the lattice data indicates a good qualitative agreement.

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26

Kaulicke, Peter. "Nota editorial." Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/113449.

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27

WANG, YU-FAN, and 王昱凡. "Accuracy Analysis and Application of Taiwan Horizontal Velocity Field." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/f7rm6e.

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碩士
國立臺北大學
不動產與城鄉環境學系
106
If the surveying results and coordinate information provided by the National Geodetic Datum can maintain long-term stability and accuracy, it will be able to effectively provide reference coordinates with certain accuracy for surveying points in various regions. However, the 1997 National Geodetic Datum which currently used in Taiwan (TWD97@2010) is still a static geodetic datum because its point coordinates does not have velocity values. Therefore, under the influence of complex surface structure and active plate movement, the accuracy of Taiwan geodetic datum will be more difficult to maintain. Since the concept of the semi-dynamic datum was put forward, Taiwan has used the GPS satellite observation continuous station and mobile station data over the years to successively calculate the speed field model required for semi-dynamic datum in Taiwan (currently completed horizontally). Therefore, this study will first verify the accuracy of the horizontal speed field in Taiwan region, and analyze the differences between measured coordinate values of Taiwan basic control points in the years 2013, 2016, and 2017 years and coordinate values based on the horizontal speed field to evaluate the feasibility of the horizontal speed field applying in Taiwan. Secondly, it proposes suggestions for the basic survey and measurement of surveying and mapping in various regions of Taiwan to serve as a reference for information maintenance, renewal, and application of basic control points in all regions.

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HUNG, CHIEN-CHIA, and 洪健嘉. "Study on the Renewed Timing of Horizontal Velocity Field in Taiwan." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/6949xc.

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Анотація:

碩士
國立臺北大學
不動產與城鄉環境學系
107
Taiwan is located at the boundary of plates, and the relative movement of plates causes the changes of surface points with time. In the past, the geodetic datum adopted the method of static datum, and comprehensive inspection of control points was adopted in the update and maintenance, which not only consumed a lot of time and labor costs, but also caused the inconvenience in cadastral survey by different datum. At present, Japan, the United States and New Zealand adopt the semi-dynamic datum of the static datum and the surface deformation model (including velocity model and coseismic model), and apply the model to modify the coordinates to the reference time to consider the surface deformation and improve the accuracy of the geodetic datum. Most of the past studies on the semi-dynamic datum in Taiwan only used one horizontal velocity field, and did not consider that the velocity field might change with the occurrence of seismic events or the passage of time. So how to find the timing and frequency of velocity field updating is an important task to improve the accuracy of deformation model. This study through the time series of GPS continuous station fitting, with major earthquake event time points as the reference, piecewise fitting for velocity, found that the time of velocity change point in the time of the major seismic event, and consistent with seismic event, mobile station fitting in the same way, getting the 12 periods of velocity field in Taiwan. Based on the velocity results of the coordinate time series fitting, it is not suitable to select the test stations to be included in the model establishment. It can be known that too short accumulation of the data of the test stations will lead to a large standard deviation of the velocity fitting. Therefore, the stability of the velocity fitting is tested in different data periods in this study. In the future establishment of velocity field model, the overall accumulation of long-term stable station coordinate data should be more than 3 years, and the station coordinate data less than 1 year should pay attention to the instability of velocity value estimation. Then, using the horizontal velocity field of 376 continuous stations and 782 mobile stations for 12 periods, the horizontal velocity grid model was established by using the Kriging method, and the difference between the actual observation and model estimation values was compared by using 19 checking stations. Taking 20 mm as the threshold value of velocity field updating, which is the most rigorous in the practical application of Taiwan’s current geodetic datum. The average service life of the horizontal velocity grid model established in Taiwan is 27 years, 18 years in the southwest, 5 years in the east, and 2 years in the past static datum. Therefore, in the future, the grid of horizontal velocity can be updated according to different frequencies and regions, and the time point of velocity change is consistent with the occurrence period of major earthquake events, so the updating of horizontal velocity field can be tracked back to the time of major earthquake.

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29

Yeh, Chi-Shian, and 葉祈賢. "Density current impact on a horizontal cylinder:Experimental flow field and force analysis." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/11445762334251555249.

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碩士
國立臺灣大學
土木工程學研究所
100
The aim of this thesis is to analysis the flow field and the force as the density current passing a horizontal cylinder. Where submarine cables and pipelines across submarine canyons, there is a danger that they will be damaged or destroyed by turbidity currents. To model this risk, the present thesis reports simplified experiments in which density currents impact a horizontal cylinder. The aim of the experiments is to simultaneously measure the force and flow field, and to relate one to the other. Laser-illuminated imaging is used to measure the unsteady velocity and density fields. On the other hand, a strain gauge is used to measure the associated force exerted on the cylinder. Inverse modeling is preformed to evaluate the pressure field and force from the velocity and density measurements, using the pressure Poisson equation. The modeled force was then compared to data retrieved from the strain gauge to evaluate the accuracy.

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30

Barlee, R. Matthew S. (Richard Matthew Scott). "Matched field and matched beam source localization using a bottom moored horizontal array." 2003. http://hdl.handle.net/1828/460.

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Presented is an analysis of the performance of a matched field and matched beam processor in localization of a shallow water source using a 63-element bottom-moored planar array. Two scenarios are considered: in the first, a stationary, submerged CW source is localized in a high SNR environment; in the second, the source is being towed in the presence of multiple ship-generated directional noise sources. Array element localization is carried out using regularized linear inversion on transients from light bulb implosions around the array. The method provides the simplest array shape solution while still fitting the data and initial hydrophone position estimates to a statistically appropriate level. Estimation of geoacoustic parameters is accomplished using a hybrid inversion algorithm producing a robust geoacoustic model which is subsequently used to produce replica acoustic fields for the full field localization methods. Localization proved highly successful for the first scenario, while increased noise and geometrical limitations led to moderate performance in the second scenario.

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31

Lee, Chien-Shing, and 李建興. "Investigation of Laminar Film Condensation Heat Transfer on Horizontal Plates and Disks under Magnetic Field Effect." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/bvn96m.

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碩士
國立成功大學
機械工程學系碩博士班
90
An analysis is conducted to study the two dimensional laminar film condensation heat transfer with the effects of applied magnetic field or downward flowing vapors onto a horizontal wavy plate or disk. In the presence of magnetic field, the electrically conducting film will be governed by the elemental force-Lorentz force. The classical condensation model of Nusselt-Rohsenow’s analysis combined with the set of magnetohydrodynamic equations is utilized to treat the liquid film layer. Another case for the free and forced convection film condensation with pure saturated vapor, the Shekriladze and Gomelauri’s shear stress model is adopted appropriately for the liquid-vapor interfacial condition. Both cases are investigated with some general assumptions like liquid inertia and energy convection terms neglected. An essential part of the present analysis is that the boundary condition at the plate edge is established by the application of Minimum mechanical energy principle from the open channel flow theory. To obtain the critical condensate layer thickness, the mass and energy equations must satisfy the conservation balance at the interface. An adequate implicit cubic spline scheme is employed for the numerical solution of the governing equations.To sum up the physical phenomena, results of the complete model were discussed in dimensionless form, including several presented parameters like Hartmann number, Rayleigh number, Jacob number and Reynolds number. According to the numerical results, the flow momentum will be retarded, but the stability and the heat transfer distribution will be increased and normalized due to the externally applied magnetic field. For film condensation of downward flowing vapor, it is found that as the vapor velocity is increasing, the mean heat transfer coefficient is changing from the free convection region into the forced convection region through a transition zone. As for the influence of wavy surface effect on the mean heat transfer coefficient, the results shows that if the total waviness number is odd, the heat transfer characteristics will be proportional to the waviness amplitude.

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32

Chang, Pei-Chen, and 張珮真. "Study on the characteristics of flow field around bubble in a fully developed horizontal pipe flow." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/69684926469201064213.

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Анотація:

碩士
國立中興大學
土木工程學系所
100
The presence of bubbles in pipeline is thought to be one of the reasons to cause hydraulic electrical and mechanical facility systems to lose their efficiency. From previous researches, the bubble reduces the effective pipe cross section, which results in a reduction in pipe capacity. The efficiency and service life of pumps and turbines were reduced and shortened consequently. It may even create the interruption of the flow field within blowout phenomenon. As a result, the presence of a bubble in the pipeline is anticipated to create potential hazards. This thesis mainly studied the characteristics of flow field around the bubble in a fully-developed horizontal pipe flow. Experiments for different bubble volumes with a single diameter in the horizontal fully-developed turbulent pipe flow were conducted. Flow visualization techniques and high time-resolved PIV system were used to carry out investigations and measurements. The observation windows of the flow field include the areas surrounding the bubble. Velocity and vorticity fields were both analyzed. The results show that the shape and volume of a bubble highly affect the flow field surrounding. Since the bubble surface is slippery, velocity vector exists on the surface of a bubble. As a result, the reverse flow in the end of a long-flat bubble wouldn’t affect the velocity on the bubble surface. The flow field around a bubble is not merely affected by the bubble surface velocity; it also shows a dynamic and irregular nature.

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33

Jafar, Farial A. "Flow fields and heat transfer of liquid falling film on horizontal cylinders." Thesis, 2011. https://vuir.vu.edu.au/19367/.

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A liquid film flowing over horizontal cylinders is of great importance as a high rate of heat transfer exists between the falling liquid film and the horizontal cylinders. The objective of this research is to use numerical predictions, following experimental verification, to study the flow field and heat transfer to better understand the heat transfer processes that occur in beds of irrigated horticultural produce. Also to refine the traditional methods of analysing heat transfer in threephase porous media by modelling the transport process in much finer detail. This objective relevant, to hydrocooler where warm produce is cooled directly by spraying it with chilled water, the process is known as hydrocooling. Other similar systems, is achieved by formulating the equations that govern heat transfer on the scale of the pieces of horticultural produce, and the spaces between them.

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34

Hsu, Chun-Yu, and 許鈞毓. "Investigation on Particle Transport Phenomena in Indium-Tin-Oxide Doped LC Cells Biased by Horizontal Electric Field." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/523qvu.

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35

Zhu, Tai Jie, and 朱泰階. "Effects of uniform cross-flow field on the convection in between differentially heated infinite horizontal parallel plates." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/21456293006539405378.

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36

Schmidtmann, G., Andrew J. Logan, Graeme J. Kennedy, G. E. Gordon, and G. Loffler. "Distinct lower visual field preference for object shape." 2015. http://hdl.handle.net/10454/9896.

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Yes
Humans manipulate objects chiefly within their lower visual field, a consequence of upright posture and the anatomical position of hands and arms.This study tested the hypothesis of enhanced sensitivity to a range of stimuli within the lower visual field. Following current models of hierarchical processing within the ventral steam, discrimination sensitivity was measured for orientation, curvature, shape (radial frequency patterns), and faces at various para-central locations (horizontal, vertical, and main diagonal meridians) and eccentricities (5° and 10°). Peripheral sensitivity was isotropic for orientation and curvature. By contrast, observers were significantly better at discriminating shapes throughout the lower visual field compared to elsewhere. For faces, however, peak sensitivity was found in the left visual field, corresponding to the right hemispheric localization of human face processing. Presenting head outlines without any internal features (e.g., eyes, mouth) recovered the lower visual field advantage found for simple shapes. A lower visual field preference for the shape of an object, which is absent for more localized information (orientation and curvature) but also for more complex objects (faces), is inconsistent with a strictly feed-forward model and poses a challenge for multistage models of object perception. The distinct lower visual field preference for contour shapes is, however, consistent with an asymmetry at intermediate stages of visual processing, which may play a key role in representing object characteristics that are particularly relevant to visually guided actions.

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37

Chang, Chun-Min, and 張中明. "A Numerical Study of the Turbulent Flow Field from Confined Five Jets Impinge on a Horizontal Moving Plate." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/05054719421039204963.

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Анотація:

碩士
逢甲大學
機械工程研究所
86
The purpose of this paper is to simulate the two dimensional five jets impinging in a confined channels by numerical study. Multiple turbulent jets flow problem is found in many practical applications, e.g., annealing of metal and glass, drying of paper and textiles or other thin films, turbine blade cooling, as well as in the secondary cooling in continuous coating of steels. The properties, such as pressure, velocity, turbulent kinetic energy, dissipation rate of the turbulent energy, and temperature distributions on the flowfield will be calculated by the PHOENICS software. The k-e two-equation turbulence model and the control-volume integration formula for finite difference and SIMPLEST algorithm are employed to simulate the two dimensional, incompressible, rectangular five- impinging-jet on a horizontal moving flat plate. The effect of the high between nozzles and ground plate, the nozzles pitch, the horizontal velocity of the impinging plate, the inlet velocity of the nozzles on the flowfield structure will be studied one by one.From the calculated results, the aspect ratio affects the flowfield strongly. For a small aspect ration the recirculation zones shrunk, and enhances the static pressure and the Nusselt number over the entireimpingement surface. The center jet behaves like a single jet, and the walljet decreases the length of the potential core and deflects the other jets. As expected, increase of the jet Renolds number also enhances theNusselt number, the turbulent kinetic energy, and the dissipation rate of theturbulent energy. The case of jets impingement on a moving surface is different from that of jet impingement on a stationary surface. The flowfield structure near the ground surface is strongly affected when the impingement surface is moving. For a slow moving impingement plate, the jets characteristics become similar to those of jets impinging on a stationary surface.

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38

Miller, Nathan. "Increasing Well Productivity in Gas Condensate Wells in Qatar's North Field." Thesis, 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-12-7356.

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Condensate blockage negatively impacts large natural gas condensate reservoirs all over the world; examples include Arun Field in Indonesia, Karachaganak Field in Kazakhstan, Cupiagua Field in Colombia,Shtokmanovskoye Field in Russian Barents Sea, and North Field in Qatar. The main focus of this thesis is to evaluate condensate blockage problems in the North Field, Qatar, and then propose solutions to increase well productivity in these gas condensate wells. The first step of the study involved gathering North Field reservoir data from previously published papers. A commercial simulator was then used to carry out numerical reservoir simulation of fluid flow in the North Field. Once an accurate model was obtained, the following three solutions to increasing productivity in the North Field are presented; namely wettability alteration, horizontal wells, and reduced Non Darcy flow. Results of this study show that wettability alteration can increase well productivity in the North Field by adding significant value to a single well. Horizontal wells can successfully increase well productivity in the North Field because they have a smaller pressure drawdown (compared to vertical wells). Horizontal wells delay condensate formation, and increase the well productivity index by reducing condensate blockage in the near wellbore region. Non Darcy flow effects were found to be negligible in multilateral wells due to a decrease in fluid velocity. Therefore, drilling multilateral wells decreases gas velocity around the wellbore, decreases Non Darcy flow effects to a negligible level, and increases well productivity in the North Field.

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39

Hwang, Jongsoo. "Gas injection techniques for condensate recovery and remediation of liquid banking in gas-condensate reservoirs." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-3558.

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In gas-condensate reservoirs, gas productivity declines due to the increasing accumulation of liquids in the near wellbore region as the bottom-hole pressure declines below the dew point pressure. This phenomenon occurs even in reservoirs containing lean gas-condensate fluid. Various methods were addressed to remediate the productivity decline, for example, fracturing, gas injection, solvent injection and chemical treatment. Among them, gas injection techniques have been used as options to prevent retrograde condensation by vaporizing condensate and/or by enhancing condensate recovery in gas-condensate reservoirs. It is of utmost importance that the behavior of liquid accumulation near the wellbore should be described properly as that provides a better understanding of the productivity decline due to the originated from impaired relative mobility of gas. In this research, several gas injection techniques were assessed by using compositional simulators. The feasibility of different methods such as periodic hot gas injection and gas reinjection using horizontal wells were assessed using different reservoir fluid and injection conditions. It is shown that both the temperature and composition of the injection fluids play a key role in the remediation of productivity and condensate recovery. The combined effect of these parameters were investigated and the resulting impact on gas and condensate production was calculated by numerical simulations in this study. Design parameters pertaining to field development and operations including well configuration and injection/production scheme were also investigated in this study along with the above parameters. Based on the results, guidelines on design issues relating gas injection parameters were suggested. The various simulation cases with different parameters helped with gaining insight into the strategy of gas injection techniques to remediate the gas productivity and condensate recovery.
text

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40

Jeans, Rhiannon. "Form perception and neural feedback: insights from V1 and V2." Thesis, 2014. http://hdl.handle.net/1885/12731.

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In the brain, every cortical inter-area feedforward projection shares a reciprocal feedback connection. Despite its pervasive nature in the brain, our understanding of the functional role of neural feedback in form perception remains incomplete, particularly in behaving animals. This problem is addressed in humans with a novel form completion paradigm. Seven subjects (5 female) had their EEG waveforms analysed using three linear models showing non-significant differences between stimulus conditions designed to produce differences by manipulating neural feedback to V1. Two of these subjects (one female), in addition to EEG waveforms, had combined magnetic resonance imaging (MRI) and functional MRI (fMRI) cortical maps that allowed anatomically close areas such as V1 and V2 to have their signals decomposed and neural feedback inferred. Differences between stimulus conditions arose once signals had been divided into V1 and V2. Significant differences (p < .05) for one subject in V1 and V2 suggests cortical interactions at 100ms and 350ms. This suggests the form completion paradigm has utility at investigating the influence of the V2 far receptive field surround on V1, given future given signal to noise issues are resolved.

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41

Swytink-Binnema, Nigel. "Digital Tuft Flow Visualisation of Wind Turbine Blade Stall." Thesis, 2014. http://hdl.handle.net/10012/8459.

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Wind turbines installed in the open atmosphere experience much more complex and highly-varying flow than their counterparts in wind tunnels or numerical simulations. In particular, aerodynamic stall—which occurs often on stall-regulated wind turbines in such variable flow conditions—can affect both wind turbine blade lifespan and noise generation. A field test site was therefore installed at the outer limits of the city of Waterloo, Ontario to study a small-scale 30 kW stall-regulated wind turbine. Experimental equipment was installed to monitor parameters such as wind speed and direction, electrical power output, blade pitch angle, rotor rotational speed, and wind turbine yaw orientation. Extensive hardware and software was developed and installed to wirelessly collect data from all instrumentation. Tufts and a remote-operated camera were also installed on one of the two blades of the 10 m diameter horizontal-axis turbine. In a variation on the tuft ﬂow visualisation technique, video ﬁles were analysed using a novel digital image processing code. The code was developed in MATLAB to calculate the fraction of the blade which was stalled by determining the position and angle of each tuft in every video frame. The algorithm was able to locate on average 85% of the visible tufts and correctly tagged those which were stalled with a bias of only −5% compared to the typical manual method. When the algorithm was applied to 7 h of tuft video at the outboard 40% of the blade, the total average fraction of stalled tufts varied from 5% at 5 m/s to 40% at 21 m/s. This trend was expected for the stall-regulated design since, as the wind speed is increased, the stall progresses from inboard to outboard regions and from trailing edge to leading edge. The 7 h time period represents at least a two order-of-magnitude increase compared with time periods analysed using previous manual methods. This work has demonstrated a digital implementation of tuft ﬂow visualisation which lends statistical validity (through long-time-period averaging) to a common tool for researching wind turbine stall. The speed and ease with which the tuft method can be implemented, combined with the high cost per energy of small-scale wind turbines, suggest that this digital algorithm is a highly beneficial tool for future studies.

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42

Su, Yuan-Te, and 蘇芫德. "Horizontal two-dimensional bed-load grain and water surface velocity fields in dam breach experiment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/49359604400294478518.

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碩士
國立臺灣大學
土木工程學研究所
103
Dam breaching consists of water flow and sediment transport. The connections between water and bed-load velocity and dam breach topography changes in downstream are the purpose in this study. Previous researches are devoted to observe dam breach phenomenon from side view. From top view, the flow field changed by terrain and the surface flow can be observed. A simplified laboratory experiment is conducted to obtain horizontal two dimensional velocity fields. In order to compare water surface and bed-load velocity, we use two different color and density particles to record water and bed-load motion synchronized. The particle tracking velocimetry (PTV) method is used to analyze velocity fields. The topography is acquired as Digital Elevation Model (DEM) using the software Photoscan, Agisoft. According to the DEM, the changing of topography can be discussed. The flow field can be projected to topography as 3 dimensional flow field. Using this approach, we successfully obtain both water surface velocities and bed-load velocities. We found that water surface velocity will affect the bed-load velocity. Besides, the topography have similar pattern to real dam breach events. Finally, the mass conservation can be used to estimate topography changing rate of bed-load if particles velocities are given.

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43

Yeh, Bea-Chun, and 葉碧純. "Three-Dimensional Global Simulation of Thermal and Flow Fields in Horizontal Zone Melting Crystal Growth System." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/01603419275286172676.

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Анотація:

碩士
國立臺灣大學
化學工程學研究所
92
The hot zone design is the most important task to decide the growth interface, the quality of the crystal and the growth rate. A computational model has been developed to simulate the three-dimensional global thermal and flow fields in horizontal zone melting crystal growth system. The method is so called “ two-level model”, which includes global model and local model. The global model includes the whole crystal growth system. We use the commercial Computational Fluid Dynamics software to combined convection/conduction/surface-to-surface radiation calculations. The melt convection and growth interface calculations in the local model are then made by the an efficient Finite volume method using multigrid acceleration within ampoule, feed, crystal, and melt, with the boundary conditions supplied by the global model simulations. The growth interface shape can be modified in the next global model simulation. The backwards and forwards calculations can be carried out until the thermal fields convergence. We also discuss the effects of gas flow on the global thermal fields and interface shape. Finally, we discuss some influences on the interface shape. To combine the two-level model can be efficient to analyze the global thermal fields and interface shape and it is helpful to design the hot zone in crystal growth system.

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44

Huang, Ping-Ray, та 黃品叡. "The μeq Fitting for Mixed Current Model of MOSFETs Considering the Effect of Horizontal and Vertical Electric Fields". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/s57bu9.

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Анотація:

碩士
國立臺北科技大學
機械工程系機電整合碩士班
106
With the progress of science and technology, the size of MOSFETs continued to shrink in order to allow MOSFETs to have better benefits, and the problems and challenges encountered have come one after another. In particular, drive current has become increasingly difficult to predict. The current of the transistor is considered to drift current. When the drain voltage reaches the saturation voltage, the reverse charge near the drain side in the channel becomes zero. The transistor enters the saturation region, causing the current no longer to increase as the drain voltage increases. But we consider that the diffusion current consists of surface charge density gradient cannot be ignored, and it even dominates the channel current. In this paper, we present a mixed current consisting of drift current and diffusion current. The inversion charge density, the effect of electric field and mobility are different at the different position in the surface channel. To make this model easier, we use the fixed mobility μeq at each position in the channel. The current at each position in the channel is equal in the same situation. We can find the μeq by using the boundary conditions, near the drain and source side. The parameters affecting μeq are the vertical electric field, horizontal electric field and channel length. We can modulate the gate voltage to change the vertical electric field and modulate drain voltage and channel length to change the electric field. This paper explores the current behavior in the linear and saturation regions, including various channel length, vertical and horizontal electric fields. The results are as expected, the reverse charge density gradient at the pinch-off point produce a diffusion current. So that there will still be diffusion current generation even if it almost no reverse charge at the pinch-off point. The reverse charge density gradient increase by the increasing drain voltage and the proportion of the total current also increase, until the drift current is completely replaced. We find how the regular changes influence μeq by modulating the horizontal, vertical electric field and channel length, it can help us to infer the current behavior that has not been measured in the limited data. The parameters that can be modulated in this paper are the channel length, gate voltage and the drain voltage. The current can be accurately simulated by using these three parameters. In the future, more parameters such as the width and the related measurement data can be taken into account, the application range of the current mode can be increased to make the model more complete. By then, IC designers can use our model to get I-V characteristics according to different situations quickly and design circuits more efficiently.

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45

Shives, Michael Robert. "Numerical models for tidal turbine farms." Thesis, 2017. http://hdl.handle.net/1828/8293.

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Анотація:

Anthropogenic climate change is approaching predicted tipping points and there is an urgent need to de-carbonize energy systems on a global scale. Generation technologies that do not emit greenhouse gas need to be rapidly deployed, and energy grids need to be updated to accommodate an intermittent fluctuating supply. Rapidly advancing battery technology, cost reduction of solar and wind power and other emerging generation technologies are making the needed changes technically and economically feasible. Extracting energy from fast-flowing tidal currents using turbines akin to those used in wind farms, offers a reliable and predictable source of GHG free energy. The tidal power industry has established the technical feasibility of tidal turbines, and is presently up-scaling deployments from single isolated units to large tidal farms containing many turbines. However there remains significant economic uncertainty in financing such projects, partially due to uncertainty in predicting the long-term energy yield. Since energy yield is used in calculating the project revenue, it is of critical importance. Predicting yield for a prospective farm has not received sufficient attention in the tidal power literature. this task has been the primary motivation for this thesis work, which focuses on establishing and validating simulation-based procedures to predict flows through large tidal farms with many turbines, including the back effects of the turbines. This is a challenging problem because large tidal farms may alter tidal flows on large scales, and the slow-moving wake downstream of each rotor influences the inflow to other rotors, influencing their performance and loading. Additionally, tidal flow variation on diurnal and monthly timescales requires long-duration analysis to obtain meaningful statistics that can be used for forecasting. This thesis presents a hybrid simulation method that uses 2D coastal flow simulations to predict tidal flows over long durations, including the influence of turbines, combined with higher-resolution 3D simulations to predict how wakes and local bathymetry influence the power of each turbine in a tidal farm. The two simulation types are coupled using a method of bins to reduce the computational cost within reasonable limits. The method can be used to compute detailed 3D flow fields, power and loading on each turbine in the farm, energy yield and the impact of the farm on tidal amplitude and phase. The method is demonstrated to be computationally tractable with modest high-performance computing resources and therefore are of immediate value for informing turbine placement, comparing turbine farm-layout cases and forecasting yield, and may be implemented in future automated layout optimization algorithms.
Graduate

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46

Hejda, Filip. "Částice a pole v křivých prostoročasech (vybrané problémy)." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-327859.

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In 2009 Bañados, Silk and West described the possibility of principally unbounded collision energies in the centre-of-mass frame for the particle collisions in the vicinity of black holes. Their work attracted a big response. This thesis aims to summarise the results of a number of the articles about the topic and puts these results into a new, broader context. It also presents some generalisations of the existing results, especially for models of magnetised black holes. The main subject of interest is the question, whether the unbounded collision energies can be achieved in a single-scattering or multiple-scattering process which was first formulated by Grib, Pavlov and Zaslavskii. Variety of methods is summarised. A considerable attention is paid to the limiting near-horizon description, which is further developed in order to derive new links and relations among known results, particularly between the purely theoretical work dealing with the geometry of degenerate horizons and their vicinity and more astrophysical articles about magnetic fluxes. Powered by TCPDF (www.tcpdf.org)

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