Orientador: José Ricardo de Arruda Miranda / Banca: Oswaldo Baffa Filho / Banca: José Carlos Rossi / Banca: Carlos Antônio Caramori / Banca: Roberto Morato Fernandez / Resumo: Não disponível. / Abstract: Not available. / Doutor

abstract: ABSTRACT A vortex tube is a device of a simple structure with no moving parts that can be used to separate a compressed gas into a hot stream and a cold stream. Many studies have been carried out to find the mechanisms of the energy separation in the vortex tube. Recent rapid development in computational fluid dynamics is providing a powerful tool to investigate the complex flow in the vortex tube. However various issues in these numerical simulations remain, such as choosing the most suitable turbulent model, as well as the lack of systematic comparative analysis. LES model for the vortex tube simulation is hardly used in the present literatures, and the influence of parameters on the performance of the vortex tube has scarcely been studied. This study is aimed to find the influence of various parameters on the performance of the vortex tube, the best geometric value of vortex tube and the realizable method to reach the required cold out flow rate 40 kg/s . First of all, setting up an original 3-D simulation vortex tube model. By comparing experiment results reported in the literature and our simulation results, a most suitable model for the simulation of the vortex tube is obtained. Secondly, we perform simulations to optimize parameters that can deliver a set of desired output, such as cold stream pressure, temperature and flow-rate. We also discuss the use of the cold air flow for petroleum engineering applications. / Dissertation/Thesis / M.S. Mechanical Engineering 2013

abstract: Teacher attrition and the migration between schools and districts can have a negative impact on quality of education and teacher performance. Novice teachers leave the profession because they are overwhelmed by the workload and responsibilities of the job. In a previous action research cycle, I found that novice teachers' perceptions of isolation and lack of opportunities to share experiences had a negative effect on teacher perceptions of efficacy. This action research project examines the effect of leveraging social media and professional learning communities to provide opportunities for a group of novice teachers to share experiences and seek advice. By addressing the challenges that novice teachers face and providing solutions for common problems, it is the hope of this researcher that highly effective teachers will remain in the classroom. The results of the study indicate that the combined use of Twitter and YouTube in collaboration with professional learning communities will improve teacher perceptions of efficacy. Teachers who participated in the social media based professional learning communities are also more likely to remain in the classroom. / Dissertation/Thesis / Ed.D. Educational Leadership and Policy Studies 2013

O propósito deste trabalho é a modelagem experimental e estudo do controle do processo de hidroconformação de tubos. Assim, o trabalho visa o projeto e a construção de um dispositivo servo-controlado de hidroconformação de tubos com um sistema de controle digital. O trabalho compreende o projeto e a construção de um dispositivo a ser acoplado em uma prensa hidráulica, a instrumentação dos equipamentos usados e a implantação do sistema de controle automático do processo através de um computador PC e de placas de interface A/D e D/A. Os aplicativos de controle foram desenvolvidos em linguagem de alto nível no sistema operacional Windows. No projeto do aplicativo, inicialmente foram realizadas rotinas para testes do sistema em malha aberta. As demais rotinas são aquelas associadas às funções matemáticas do modelo fenomenológico do sistema de hidroconformação, aquelas destinadas ao controlador de malha fechada. O tipo de estratégia de controle a ser utilizada foi definida no decorrer do projeto e foi baseada em um modelo de processo não linear, linearizado em torno de cada ponto de operação. Para fins de obtenção do modelo nominal para o controlador, os atuadores e sensores tiveram suas dinâmicas desprezadas face a dinâmica do processo e suas curvas de processo foram levantadas experimentalmente. / This works aims is the experimental modeling of a tube hydroforming (THF) “T” branch, and de THF process automatic control study. Thus, the design and the construction of a servo-controlled hydraulic device for THF, with a automatic digital control system, is embedded in our objectives. Design and construction of device to append on a hydraulic press, implantation of the measurement equipment and implementation of the control system algorithms through a PC with I/O interface boards is necessary. Control algorithms were developed in Hi-level language for windows operating system. The application design was based on experimental initial tests performed with no feed-backing controlling mode. Routes related to phenomenological mathematical model of the THF process were validate against the literature database, and were devoted to the feed-backing controller mode. Control strategy to employ in final application was defined during the process calibration, based on the non-linear characteristics of the “T” branch THF. To obtain the final load path model sensors and cylinders had their dynamics neglected because the THF dynamic is very much higher, and had their behavior curves experimentally raised.

Class of 2017 Abstract / Objectives: The specific aims of this project were to evaluate the incidence of carboplatin HSR in patients with the BRCA1 or BRCA2 mutations compared to those without these mutations. Secondary objectives were to identify carboplatin cycles where reactions occurred, grade of reaction, and treatment outcomes. Methods: This retrospective chart review included 167 ovarian, fallopian tube, and primary peritoneal cancer patients at the University of Arizona Cancer Center who underwent a regimen with carboplatin from 2013-2015. Results: 126 out of 167 patients were analyzed. HSR occurred in 4 patients with BRCA mutations, and in 9 patients without mutations, though incidence was not significant with respect to the groups (3.1% versus 17.4%, P=0.5291). Overall, there were 11 grade 1 reactions, 14 grade 2 reactions, and 16 grade 3 reactions to carboplatin. Conclusions: Presence of a BRCA1/2 mutation was not associated with a higher incidence of HSR in carboplatin. More studies are needed to clarify the impact of BRCA mutations on developing carboplatin HSR.

The conceptual design and basic layout of a modular refrigerant test system capable of flow condensation and evaporation were performed. The purpose of this study was the investigation of flow patterns during refrigerant condensation in intermittent flow in order to improve the prediction models. An objective flow pattern descriptor was developed to identify and describe transitions in flow regimes. The methods developed and utilised in this study were used to develop a time-fractional map of the intermittent flow regime. The time-fractions are statistical averages of gravity dominated and shear dominated flows occurring in intermittent flow. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2008. / Mechanical and Aeronautical Engineering / MEng / Unrestricted

This thesis provides an assessment of various computational strategies for modelling the turbulent flow and heat transfer around in-line tube banks. The research has direct application to the heat exchanger of an Advanced Gas-cooled Reactor (AGR). The suitability and accuracy of different Computational Fluid Dynamic (CFD) techniques were investigated first on generic square in-line tube banks where experimental data are available. The assumption of flow periodicity in all three Cartesian directions is initially investigated whereby the domain size was varied. Wall-resolved Large Eddy Simulations (LES) predict an increasing flow asymmetry with decreasing tube spacing. Two dimensional (2D) and three dimensional (3D) Unsteady Reynolds Averaged Navier-Stokes (URANS) models were simulated at the tube spacing known to be close to the flow pattern transition from symmetric to asymmetric. Marked differences were observed between the flow pattern predicted by turbulence models resolving the boundary layer and those that rely on wall functions. Ultimately, an improved understanding of the flow physics and heat transfer mechanisms encountered within in-line tube banks was gained. The assumption of flow periodicity was then removed and the effects of confining walls were investigated by reproducing experimental conditions. The correct pressure forces and heat transfer around the central tubes could only be accurately predicted when the walls in the crossflow direction were modelled. The inclusion of walls in the spanwise direction gave rise to small flow asymmetries which have been reported on similarly-spaced in-line tube banks. The latter half of the thesis focuses on the reasons for the enhanced thermal mixing and 3D secondary flow patterns observed in the in-line section of the AGR heat exchanger. A wall-resolved periodic LES was conducted at the lower Reynolds number of 11,000 along with URANS calculations of the full experimental conditions at both Reynolds numbers 11,000 and 66,000. These calculations required the use of High Performance Computing (HPC) facilities. Large 3D secondary flow structures were predicted that produced the same level of crossflow temperature drifting as that reported experimentally. Multiple upward and downward flow paths were observed which qualitatively explained why the experimental temperature profiles reported at different spanwise locations indicated multiple spirals (or secondary vortices). Quantification of the levels of thermal diffusion were investigated using both decaying temperature spikes and blanked tube platens. Thus the CFD provided recommendations about the thermal diffusivity assumptions used by the AGR heat exchanger code.

A 30.5 cm diameter, detonation driven shock tube facility has been designed, constructed and tested. The design goals of the shock tube were to reproduce free field blast wave profiles on a laboratory scale using atmospheric gaseous detonation as the energy source. Numerical simulations were utilized to explore the gas dynamic evolution inside detonation driven shock tubes and to select the optimal design parameters for the shock tube.The Friedlander profile was used to evaluate the generated pressure profiles as an approximation of free field blast waves. It has been found that the detonation driver length should be kept below 20% of the total length of the tube in order to produce Friedlander waves. Additionally, it has been found that an annular vent can be added to the shock tube to enhance the negative phase of the blast profile, more accurately reproducing real free field blast waves. The shock tube has been constructed in a modular fashion from 2.54 cm thick steel tubing. An adjustable bag type diaphragm has been employed to allow for a variable driver size and a high voltage ignition system is used to initiate detonation in the driver section. Due to the available location for the shock tube, tests using the vented configuration could not be accomplished for safety reasons. Conducted experiments produced results that agree well with corresponding numerical simulations. Overall, the shock tube design was successful in creating Friedlander blast waves. At the time of writing, a manufacturer error in correctly reporting the specifications of the clamps used on the shock tube resulted in a lower maximum pressure of operation.

Recent attacks and accidental explosions have demonstrated the necessity of ensuring the blast resistance of critical buildings and infrastructure in Canada such as federal and provincial offices, military buildings and embassies. Of particular importance is the blast resistance of ground-story columns in buildings which must be properly detailed to provide the necessary strength and ductility to prevent progressive collapse. There exists a need to explore the use of innovative materials that can simultaneously improve the performance of such columns, while also allowing for a relaxation of required detailing to ease construction. Advancements in concrete material science have led to the development of ultra-high performance fiber reinforced concretes (UHPFRC) which show superior mechanical properties when compared to conventional concrete, such as increased compressive strength, tensile resistance and toughness. These enhanced properties make UHPFRC an attractive material for use in the blast design of reinforced concrete columns. This thesis presents the results of a research program examining the performance of UHPFRC columns under simulated blast loads. As part of the experimental program twelve half-scale UHPFRC specimens, six built with regular grade steel reinforcement and six built with steel high-strength steel reinforcement, are tested under blast loading using the University of Ottawa shock tube. The specimens were designed according to CSA A23.3 standard requirements for both seismic and non-seismic regions, using various fibre types, fibre amounts and longitudinal reinforcement ratios, allowing for an investigation of various design parameters on blast behaviour. The results demonstrate that the use of UHPFRC improves the blast performance of columns by reducing displacements, increasing resistance and enhancing damage tolerance. The results also indicate that fiber content, fiber properties, seismic detailing, longitudinal reinforcement ratio and longitudinal reinforcement strength are factors which can affect the behaviour and failure mode of UHPFRC columns. As part of the analytical study the response of the UHPFRC columns is predicted using dynamic inelastic analysis. The dynamic responses of the columns are predicted by generating dynamic load-deformation resistance functions for UHPFRC and conducting single-degree-of-freedom (SDOF) analysis using software RC-Blast.

Despite the on-going intensity of research in the field of protective structural design, one topic that has been largely ignored in the literature is the effect of high strain rates on the bond between reinforcing steel and the surrounding concrete. Therefore, a comprehensive research program was undertaken to establish the effect of high strain rates on reinforced concrete bond. The experimental research consisted of the construction and testing of fourteen flexural beam-end bond specimens and twenty-five lap-spliced reinforced concrete beams. The physical and material properties of the specimens were selected based on a range of design parameters known to significantly influence bond strength. In order to establish a baseline for comparison, approximately half of the total number of specimens were subjected to static testing, while the remainder were subjected to dynamic loading generated using a shock tube. The strain rates generated using the shock tube were consistent with those obtained for mid- and far-field explosive detonation. Results of the beam-end and lap splice beam tests showed that the flexural behaviour of reinforced concrete was significantly stronger and stiffer when subjected to dynamic loading. Furthermore, the high strain rate bond strength was always greater than the corresponding low strain rate values, yielding an average dynamic increase factor (DIF) applied to ultimate bond strength of 1.28. Analysis of the low and high strain rate test results led to the development of empirical expressions describing the observed strain rate sensitivity of reinforced concrete bond for spliced and developed bars with and without transverse reinforcement. The predictive accuracy of the proposed DIF expressions was assessed against the experimental results and data from the literature. It was found that the dynamic bond strength of reinforced concrete can be predicted with reasonably good accuracy and that the proposed DIF expressions can be used for analysis and design of protective structures. An analytical method was also developed to predict the flexural load-deformation behaviour of reinforced concrete members containing tension lap splices. The analysis incorporated the effect of reinforcement slip through the use of pseudo-material stress-strain relationships, in addition to giving consideration to the effect of high strain rates on bond-slip characteristics and on the material properties of concrete and steel. A comparison of the analytical predictions with experimental data demonstrated that the proposed analysis technique can reasonably predict the flexural response of beams with tension lap splices. The results also demonstrated that the model is equally applicable for use at low- and high-strain rates, such as those generated during blast and impact.