Abstract This study investigates the waves and current field interaction with a perforated floating breakwater which is fastened by tension lags. As the predecessor done, the porous media governing equation is adopted inside the perforated floating breakwater, but a control volume concept has been applied in the breakwater in order to find the external forces on the system. A new dispersion equation has been introduced with the fact of the uniform current influence on the reflection waves (moving upstream direction) and the transmission waves (moving downstream direction). Since the whole system belongs to a domain problem and also assumes it can be linearlized, a boundary element method (BEM) is developed to solved the problem. To confirm this new BEM is correct and accuracy, a zero current has been set and compared its results with analytical solutions that was published by the predecessor. The comparison between the new BEM and analytical solutions has good agreements. It means the BEM developed by this paper has its own accuracy. Based on the same numerical model, a floating breakwater and waves/current interaction problems are investigated. The results have shown that the uniform current will degrade the reflection coefficients but increase the transmission coefficients. In general, the perforated floating breakwater, which is deeper under the water and longer in width, has smaller transmission coefficients. But practically when designing a perforated floating breakwater, we still suggest to increase the width rather than to deepen the depth. It is because the effects of dissipating wave energy are more obvious when increasing the width.

Magnetic resonance imaging (MRI) has revolutionized the field of cognitive neuroscience as it allows researchers to noninvasively map brain function in response to stimulus or task demands. However, the acquisition of MR images generates substantial acoustic noise, so that imaging studies of speech, language and hearing are problematic. One proven solution for reducing acoustic noise in MRI scanners is the use of micro-perforated panels placed in the bore of the scanner. They can be applied to existing scanners with minimal cost and are suitable for sterile environments. Although these panels result in quantifiably lower noise levels, measured with microphones in an empty MRI, the improvement has not been quantified with a patient in the scanner bore, which dramatically affects the acoustic noise field. This thesis tested the reduction of noise inside the MRI environment using a previously designed micro-perforated acoustic absorber panel. These panels resulted in quantifiably lower noise levels with a volunteer in the scanner bore, however the reduction was not sufficient for significant differences in volunteer perceptions. Volunteers were generally unable to perceive a difference in noise between scans with and without absorbers and no reduction of fatigue was observed. Also no significant change in cortical activity was found between scans done with and without absorbers during an auditory function MRI study. Further testing could include designing a micro-perforated acoustic absorber for a specific scan sequence for maximum attenuation. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-09-25 16:54:41.118

Submitted by Gabriel Leonardo Nogueira (gabrielnogueira5@hotmail.com) on 2016-11-02T14:46:19Z No. of bitstreams: 1 Dissertação Gabriel FINAL corrigida.pdf: 3857264 bytes, checksum: 37885bf252f0c527d86237d787b4fe47 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-11-10T12:25:58Z (GMT) No. of bitstreams: 1 nogueira_gl_me_prud.pdf: 3857264 bytes, checksum: 37885bf252f0c527d86237d787b4fe47 (MD5) / Made available in DSpace on 2016-11-10T12:25:58Z (GMT). No. of bitstreams: 1 nogueira_gl_me_prud.pdf: 3857264 bytes, checksum: 37885bf252f0c527d86237d787b4fe47 (MD5) Previous issue date: 2016-08-26 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O transistor orgânico de efeito de campo com arquitetura vertical (VOFET) possibilita contornar as principais limitações de um transistor orgânico de efeito de campo (OFET) convencional. Nesta estrutura, as camadas são empilhadas verticalmente, de modo que os eletrodos de fonte e dreno são separados pela camada semicondutora e o comprimento do canal definido pela espessura do filme semicondutor. Para o VOFET proposto, utilizou-se Al e Al2O3 (obtido por anodização) como eletrodo e dielétrico de gate, respectivamente. O filme semicondutor foi obtido pela deposição por spincoating de P3HT dissolvido em clorofórmio. Os eletrodos de fonte e dreno foram obtidos por evaporação térmica a vácuo. Ao utilizar Al e Au como fonte e dreno, respectivamente, foi possível estudar os dispositivos de dois terminais que compõe o VOFET. Com base nesses dispositivos, importantes parâmetros da estrutura vertical foram determinados, como capacitância do dielétrico (~265 nF/cm2), densidade de portadores e mobilidade do P3HT (NA = 9,2 x 1016 cm-3 e μ = 1,5x10-4 cm2V-1s-1). Para utilizar Sn como eletrodo de fonte, o filme foi avaliado por meio de medidas de resistência e capacitância, aliadas à analise morfológica por AFM. Observa-se que a adição de uma camada de PMMA sobre o Al2O3 melhora o desempenho do VOFET. Para o VOFET formado por Al2O3/PMMA (20 nm/14 nm), com Sn e Al como fonte e dreno, foram calculados os valores de densidade de corrente (Jeff = 7x10-3 mA/cm2), voltagem e campo limiar (VTH = -8V e ELIMIAR = 330 MV/m). Com isso, foi obtido um VOFET utilizando filme de Sn evaporado como eletrodo de fonte perfurado. / A way of circumvent the limitations of conventional organic field-effect transistor (OFET), is by using the vertical organic field-effect transistor (VOFET). In this structure, with layers stacked vertically, the semiconductor is sandwiched between source and drain electrodes, where the channel length is determined by the thickness of the semiconductor film. In this study, we report a VOFET with Al and Al2O3 (obtained by anodization) as electrode and dielectric of gate, respectively. The semiconductor film was obtained by spin-coating of the P3HT in chloroform. We obtained the source and drain electrodes by vacuum thermal evaporation. The use of Al and Au as source and drain, respectively, enabled the investigation of the two devices contained in the VOFET (MIM capacitor, Schottky diode and MIS capacitor). Important parameters were determinate, as dielectric capacitance (~265 nF/cm2), charrier density and mobility of P3HT (NA = 9,2 x 1016 cm-3 e μ = 1,5x10-4 cm2V-1s-1), etc. To use Sn as source electrode, the film (by evaporation) was investigated by measurements of resistance and capacitance, combined with morphological analysis by AFM. We observed that the addiction of PMMA layer on Al2O3 improves the performance of VOFET. For VOFET obtained by using Al2O3/PMMA (20 nm/14 nm) as dielectric layer, with Sn and Al as source and drain, respectively, were calculate the values of current density (Jeff = 7x10-3 mA/cm2), threshold voltage and electric field (VTH = -8V e ETH = 330 MV/m). Thereat, we obtained a VOFET by evaporation of a thin film of Sn as perforated source electrode. / FAPESP: 2013/26973-5

Perforated tubes are widely used in industry for various applications. A special application arises when there is fluid injection into the perforated tube. Such cases arise when perforated tubes are used for horizontal oil well drilling and French drains. The behaviour of the flow under these conditions has led to the development of correlations, which consider the effects of the perforations and injection process. However, there are few friction factor correlations in literature, which consider the increased kinetic energy at the perforated tube outlet caused by fluid injection and acceleration. The current study reports experimental correlations for determining the friction factor of perforated tubes when the additional kinetic energy from the injection process is considered. The friction factor measurements were conducted in copper tubes with an internal diameter of 20.8 mm and a wall thickness of 1 mm at three nondimensional pitches of 0.375, 0.75 and 1.5. A perforated length-to-diameter ratio of 40:1 was used for the perforated tubes. A perforation row contained seven small perforation holes with a diameter of 1.5 mm spaced evenly around the perimeter of the tube. These perforation rows were staggered row to row, resulting in triangular perforation patterns. Water was used as a test medium with Reynolds numbers at the tube outlet ranging from 20 000 to 60 000. The injection ratio was varied from 0 to 5% to obtain a total of 135 unique combinations of perforated tube friction factor data at different injection ratios, Reynolds numbers and nondimensional perforation pitches. The experiments were condensed into friction factor correlations, which allow perforated tube parameters to be optimisation for minimising pressure losses encountered in draining operations. Copyright / Dissertation (MEng)--University of Pretoria, 2011. / Mechanical and Aeronautical Engineering / unrestricted

No / A comprehensive study of the internal flow field for the prilling application in a perforated rotating bucket has been carried out. Computational Fluid Dynamics (CFD) is used to investigate the flow field of urea melt inside the perforated rotating bucket. The bucket is mounted at the top of the prilling tower. In prilling process, urea melt is sprayed by the perforated rotating bucket to produce the urea droplets, which falls down due to gravity. These drops fall down through a cooling medium and solidify into prills. The velocity field in the bucket is very important to study, as it has great effect on the heat and mass transfer performance in prilling process. ANSYS 14.0 CFD package is used to simulate and Design Modeler and Catia V5 are used for geometrical model of the perforated prilling bucket. Velocity distribution on different planes are obtained and discussed.

Operating within a dense urban context, a public building recognizes the activities that are contained within its boundaries... further tying the place to a larger urban spatial sequence. / Master of Architecture

Motivação: A introdução do medicamento antagonista H2, e a descoberta do papel do Helicobacter pylori, na patogênese da úlcera péptica, diminuiu a indicação cirúrgica da doença ulcerosa. Todavia, a incidência de perfuração na doença ulcerosa tem se mantido constante, e o tratamento cirúrgico é a conduta mais indicada. A mortalidade nesta circunstância continua expressiva. Objetivo: Este trabalho teve como objetivo analisar possíveis fatores de risco de mortalidade no tratamento da úlcera gastroduodenal perfurada tratada com cirurgia. Casuística e métodos: Foram estudados 311 pacientes (268 do sexo masculino e 43 do sexo feminino), sendo 242 portadores de úlcera duodenal e 69 de úlcera gástrica, no período de janeiro de 1997 a dezembro de 2000. Ocorreram 35 óbitos (11,25%). Analisaram-se os seguintes fatores: idade, sexo, tabagismo, etilismo, doença ulcerosa prévia, uso de antiinflamatório, pneumoperitônio, doenças concomitantes, choque na admissão, tempo de perfuração, peritonite, tipo de cirurgia e local de perfuração. Os fatores de risco de mortalidade nos dois tipos de úlcera foram comparados descritivamente utilizando-se o odds ratio, os percentuais de mortalidade, o teste de Zelen e análise de regressão logística univariada e multivariada. Destaca-se que a maioria do pacientes foi submetida ao tratamento cirúrgico não definitivo, sendo o critério utilizado para definir o tipo de cirurgia determinado por escolha aleatória da equipe cirúrgica. Resultados: Os fatores de risco associados à mortalidade na úlcera gastroduodenal perfurada identificados na análise univariada foram: idade (UG), pneumoperitônio, doenças concomitantes, local de perfuração, choque na admissão e tempo de perfuração. A presença do pneumoperitônio é um sinal radiológico importante no diagnóstico da úlcera gastroduodenal perfurada. Na sua ausência, ocorreu aumento de incidência de mortalidade. A incidência de mortalidade na úlcera gástrica perfurada foi maior no idoso. Na úlcera gástrica a incidência de mortalidade foi maior do que na úlcera duodenal. Entretanto, a análise multivariada mostrou que os fatores de risco independentes preditivos de mortalidade foram na úlcera duodenal: tempo de perfuração maior que 24 horas, doenças concomitantes e choque na admissão e na úlcera gástrica: idade, tempo de perfuração maior que 24 horas e choque na admissão. Conclusões: O risco aumentado de mortalidade na úlcera gastroduodenal perfurada pode ser previsto quando os pacientes apresentam idade avançada (UG), doenças concomitantes (UD), tempo de perfuração maior que 24 horas, e choque na admissão hospitalar / Motivation: The introduction of the H2 antagonist drug and the discovery that the Helicobacter pylori played a role in the pathogenesis of the peptic ulcer caused a decrease in the indication of surgical treatment for ulcer disease. However, the incidence of perforation in ulcer disease has remained constant, and surgical treatment is the most indicated treatment modality. In these cases, the rate of mortality is still significant. Objective: This paper aimed at analyzing the risk factors for mortality in the surgically treated perforated gastroduodenal ulcer. Cases and methods: 311 patients were studied (268 males and 43 females), seeing that 242 were duodenal ulcer carriers and 69 gastric ulcer, in the period from January 1997 to December 2000. Thirty-five patients died (11,25%). The following factors were analyzed: age, sex, smoking, chronic alcohol consumption, previous ulcer disease, use of anti-inflammatory medication, pneumoperitoneum, concomitant diseases, shock upon admittance, time lapsed since perforation, peritonitis, type of surgery and perforation site. The risk factors for mortality in the two types of ulcer were compared descriptively, using the odds ratio, percentage of mortality, the Zelen test and the univariate and multivariate logistic regression analysis. It is worth pointing out that most of the patients had undergone nondefinitive surgical treatment and the criterion used to decide the type of surgery was random selection by the surgical team. Results: The risk factors associated to mortality in the perforated gastroduodenal ulcer identified by the univariate analisys were: age (GU), pneumoperitoneum, concomitant diseases, perforation site, shock upon admittance, time lapsed since perforation, peritonitis and type of surgery. The presence of pneumoperitoneum is an important radiological sign for the diagnosis of the perforated peptic ulcer. When this diagnostic tool was not used, an increase in the incidence of mortality was observed. The incidence of mortality for perforated gastric ulcers was higher in elderly patients. The incidence of mortality was higher for gastric ulcers relative to duodenal ulcers. However, the multivariate analysis showed that independent predictive risk factors for mortality were the following, for the duodenal ulcer: time lapse of more than 24 hours since perforation, severe coexisting diseases and shock at the time of admittance; for gastric ulcer: age, time lapse of more than 24 hours, from moment perforation and shock at the time of admittance. Conclusion: The increased risk of mortality for perforated duodenal ulcer can be predicted when the patients are elderly (GU), when there are concomitant diseases (DU), the time lapsed from the moment of perforation exceeds 24 hours, and when the patients are in shock at the time of admittance

Motivação: A introdução do medicamento antagonista H2, e a descoberta do papel do Helicobacter pylori, na patogênese da úlcera péptica, diminuiu a indicação cirúrgica da doença ulcerosa. Todavia, a incidência de perfuração na doença ulcerosa tem se mantido constante, e o tratamento cirúrgico é a conduta mais indicada. A mortalidade nesta circunstância continua expressiva. Objetivo: Este trabalho teve como objetivo analisar possíveis fatores de risco de mortalidade no tratamento da úlcera gastroduodenal perfurada tratada com cirurgia. Casuística e métodos: Foram estudados 311 pacientes (268 do sexo masculino e 43 do sexo feminino), sendo 242 portadores de úlcera duodenal e 69 de úlcera gástrica, no período de janeiro de 1997 a dezembro de 2000. Ocorreram 35 óbitos (11,25%). Analisaram-se os seguintes fatores: idade, sexo, tabagismo, etilismo, doença ulcerosa prévia, uso de antiinflamatório, pneumoperitônio, doenças concomitantes, choque na admissão, tempo de perfuração, peritonite, tipo de cirurgia e local de perfuração. Os fatores de risco de mortalidade nos dois tipos de úlcera foram comparados descritivamente utilizando-se o odds ratio, os percentuais de mortalidade, o teste de Zelen e análise de regressão logística univariada e multivariada. Destaca-se que a maioria do pacientes foi submetida ao tratamento cirúrgico não definitivo, sendo o critério utilizado para definir o tipo de cirurgia determinado por escolha aleatória da equipe cirúrgica. Resultados: Os fatores de risco associados à mortalidade na úlcera gastroduodenal perfurada identificados na análise univariada foram: idade (UG), pneumoperitônio, doenças concomitantes, local de perfuração, choque na admissão e tempo de perfuração. A presença do pneumoperitônio é um sinal radiológico importante no diagnóstico da úlcera gastroduodenal perfurada. Na sua ausência, ocorreu aumento de incidência de mortalidade. A incidência de mortalidade na úlcera gástrica perfurada foi maior no idoso. Na úlcera gástrica a incidência de mortalidade foi maior do que na úlcera duodenal. Entretanto, a análise multivariada mostrou que os fatores de risco independentes preditivos de mortalidade foram na úlcera duodenal: tempo de perfuração maior que 24 horas, doenças concomitantes e choque na admissão e na úlcera gástrica: idade, tempo de perfuração maior que 24 horas e choque na admissão. Conclusões: O risco aumentado de mortalidade na úlcera gastroduodenal perfurada pode ser previsto quando os pacientes apresentam idade avançada (UG), doenças concomitantes (UD), tempo de perfuração maior que 24 horas, e choque na admissão hospitalar / Motivation: The introduction of the H2 antagonist drug and the discovery that the Helicobacter pylori played a role in the pathogenesis of the peptic ulcer caused a decrease in the indication of surgical treatment for ulcer disease. However, the incidence of perforation in ulcer disease has remained constant, and surgical treatment is the most indicated treatment modality. In these cases, the rate of mortality is still significant. Objective: This paper aimed at analyzing the risk factors for mortality in the surgically treated perforated gastroduodenal ulcer. Cases and methods: 311 patients were studied (268 males and 43 females), seeing that 242 were duodenal ulcer carriers and 69 gastric ulcer, in the period from January 1997 to December 2000. Thirty-five patients died (11,25%). The following factors were analyzed: age, sex, smoking, chronic alcohol consumption, previous ulcer disease, use of anti-inflammatory medication, pneumoperitoneum, concomitant diseases, shock upon admittance, time lapsed since perforation, peritonitis, type of surgery and perforation site. The risk factors for mortality in the two types of ulcer were compared descriptively, using the odds ratio, percentage of mortality, the Zelen test and the univariate and multivariate logistic regression analysis. It is worth pointing out that most of the patients had undergone nondefinitive surgical treatment and the criterion used to decide the type of surgery was random selection by the surgical team. Results: The risk factors associated to mortality in the perforated gastroduodenal ulcer identified by the univariate analisys were: age (GU), pneumoperitoneum, concomitant diseases, perforation site, shock upon admittance, time lapsed since perforation, peritonitis and type of surgery. The presence of pneumoperitoneum is an important radiological sign for the diagnosis of the perforated peptic ulcer. When this diagnostic tool was not used, an increase in the incidence of mortality was observed. The incidence of mortality for perforated gastric ulcers was higher in elderly patients. The incidence of mortality was higher for gastric ulcers relative to duodenal ulcers. However, the multivariate analysis showed that independent predictive risk factors for mortality were the following, for the duodenal ulcer: time lapse of more than 24 hours since perforation, severe coexisting diseases and shock at the time of admittance; for gastric ulcer: age, time lapse of more than 24 hours, from moment perforation and shock at the time of admittance. Conclusion: The increased risk of mortality for perforated duodenal ulcer can be predicted when the patients are elderly (GU), when there are concomitant diseases (DU), the time lapsed from the moment of perforation exceeds 24 hours, and when the patients are in shock at the time of admittance

This thesis presents experimental work and numerical analysis that has been undertaken to assess the bearing capacity of perforated offshore foundations. Perforated foundations may be used to support subsea infrastructure, including as mudmats into which a number of perforations have been made, or as grillages which consist of a series of structurally connected strip footings. Larger gravity base foundations, such as for offshore wind turbines or oil and gas platforms, may adopt a single central perforation. The advantages of using perforated foundations can include reduced material requirements and easier offshore handling as a result of smaller weight and lower hydrodynamic forces during deployment. Limited guidance currently exists for assessing the bearing capacity of these foundation types. Bearing capacity of perforated foundations has been examined in this thesis under conditions of combined vertical, horizontal and moment loading which is typical in offshore settings. Undrained soil conditions have been considered, except for the case of grillages in which drained conditions are often most relevant. Experimental work has included centrifuge testing of ring and square annular foundations on clay, and 1g testing of grillage foundations on sand. Finite element modelling has also been undertaken to assess perforated foundation capacity. A Tresca material subroutine (UMAT) and an adaptive meshing scheme have been developed to improve the accuracy of the finite element analysis carried out. The results showed that perforated foundations can be an efficient foundation solution for accommodating combined loading. As a ratio of their vertical load capacity, perforated foundations may be able to withstand higher moment and horizontal loads compared with unperforated foundations. The experimental and numerical results have been used to develop design expressions that could be employed by practitioners to estimate the vertical and combined load bearing capacity of these foundation types.

Thesis (MEng)--Stellenbosch University. / ENGLISH ABSTRACT: see item for full text / AFRIKAANSE OPSOMMING: sien item vir volteks.