Orientador: Yukio Kobayashi / Banca: Paulo César Rioli Duarte de Souza / Banca: Gilberto de Magalhães Bento Gonçalves / Resumo: No presente trabalho buscou-se determinar o comportamento das características geométricas do cordão da solda e o desempenho da soldagem, através do processo de soldagem com arame tubular autoprotegido e corrente pulsada. As características geométricas estudadas foram largura do cordão, penetração da solda e altura do reforço. Para definir o desempenho da soldagem analisou-se o rendimento de deposição e a taxa de deposição. Como metal de base utilizou-se o aço ABNT 1010 de espessura 6,35mm. O arame utilizado foi o AWS E71T-11 com diâmetro 1,1mm. A soldas foram realizadas por simples deposição, utilizando-se uma fonte de solda microprocessada, mantendo-se a velocidade de soldagem e a distancia tocha/peça constante. Durante o processo de soldagem os parâmetros de pulso analisados foram a corrente de pico (Ap), corrente de base (Ab), freqüência de pulso (F) e tempo de pico (Tp). Para coleta dos dados foi utilizada uma placa de aquisição de dados com interface a um microcomputador. De posse dos dados, foi aplicada a técnica de ANOVA, com o objetivo de identificar, quantificar e localizar a significância das dispersões. Verificou-se que a tensão média tem grande influência nas características geométricas do cordão de solda e de desempenho da soldagem. Para cada incremento de F provocou uma redução da largura do cordão de solda e aumento da penetração, altura do reforço, taxa de deposição e rendimento de deposição. O incremento Tp acarretou a formação de cordões mais largos, como também a redução na altura do reforço, penetração, taxa de deposição e rendimento de deposição. A variação de Ap não teve influência sobre largura do cordão, a altura do reforço, taxa de deposição e rendimento de deposição. / Abstract: In the present work one searched to determine the behavior of the geometric characteristics of the bead weld and the performance of the welding, through the process self-shielded flux cored arc welding and pulsed current. The studied geometric characteristics had been width of bead, penetration of the weld, height of the reinforcement. To define the performance of the welding one analyzed the deposition efficiency and the deposition rate. As metal base was used steel ABNT 1010 with thickness 6, 35 mm. The used wire was the AWS E71T-11 with diameter 1,1 mm. The welds had been carried through by simple deposition, using themselves a microprocessed weld power source, remaining constant it welding speed and the stick-out. During the welding process the analyzed parameters of pulse had been the peak current (Ap), base current (Ab), pulse frequency (F) and peak duration (Tp). For collection of the data a plate of acquisition of data with interface to a microcomputer was used. Of ownership of the data, the ANOVA technique was applied, with the objective to identify, to quantify and to locate the significance of the dispersions. It was verified that the mean voltage has great influence in the geometric characteristics of the bead weld and the performance of the welding. For each increment of F it provoked a reduction of the width of the bead weld and increase of the penetration, height of the reinforcement, deposition rate and deposition efficiency. The Tp increment caused the wider bead weld formation, as also the reduction in the height of the reinforcement, penetration, deposition rate and deposition efficiency. The variation of Ap did not have influence on width of the bead weld, the height of the reinforcement, deposition rate and deposition efficiency. / Mestre

This thesis concerns the development of alternate bars under steady state flows. The movable bed is flat at the beginning of the experiment; the bars reach their equilibrium or developed state at the time Td. The thesis has two objectives. The first is to introduce new equations for the geometric characteristics, namely height and length, of alternate bars at the fully developed stage, and to evaluate them against the existing equations. The second objective is to present the results of two series of experiments carried out to characterize the process of development of alternate bars and obtain estimates of their time of development. The data resulting from these experiments are intended as a foundation for future work towards the establishment of a predictive equation for the development time of alternate bars. The new equations for bar height and length rest on dimensional considerations and all the available data. Bars produced under rough turbulent and transitional flows are treated separately. The proposed equations are found to consistently give more accurate estimates of alternate bar dimensions than existing equations. The experiments to quantify the time of development of alternate bars are carried out in the 21 m long, 0.76 m wide sediment transport flume of the Queen’s Coastal Engineering Laboratory. In addition to providing estimates of the time of development of alternate bars, these experiments reveal aspects of the process of development of alternate bars that had not been reported previously. In particular, they show that, all other conditions being the same (including the sediment transport capacity of the initial flow), the more pronounced alternate bars formed under shallower flows develop faster than less pronounced bars formed under deeper flows. The findings of this study highlight the fact that the previously unexplained wide variation in alternate bar dimensions is related to the plotting position of the data point in the alternate bar existence region of Ahmari and da Silva (2011). This study also sheds light on the evolution and development of alternate bars, which establishes a strong foundation for future studies on the topic. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2014-03-30 16:27:07.025

Made available in DSpace on 2014-06-11T19:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-01-20Bitstream added on 2014-06-13T20:17:59Z : No. of bitstreams: 1 correa_frt_me_bauru.pdf: 1326371 bytes, checksum: a4dd5287d93dc0ae01a81f1278a10ffd (MD5) / No presente trabalho buscou-se determinar o comportamento das características geométricas do cordão da solda e o desempenho da soldagem, através do processo de soldagem com arame tubular autoprotegido e corrente pulsada. As características geométricas estudadas foram largura do cordão, penetração da solda e altura do reforço. Para definir o desempenho da soldagem analisou-se o rendimento de deposição e a taxa de deposição. Como metal de base utilizou-se o aço ABNT 1010 de espessura 6,35mm. O arame utilizado foi o AWS E71T-11 com diâmetro 1,1mm. A soldas foram realizadas por simples deposição, utilizando-se uma fonte de solda microprocessada, mantendo-se a velocidade de soldagem e a distancia tocha/peça constante. Durante o processo de soldagem os parâmetros de pulso analisados foram a corrente de pico (Ap), corrente de base (Ab), freqüência de pulso (F) e tempo de pico (Tp). Para coleta dos dados foi utilizada uma placa de aquisição de dados com interface a um microcomputador. De posse dos dados, foi aplicada a técnica de ANOVA, com o objetivo de identificar, quantificar e localizar a significância das dispersões. Verificou-se que a tensão média tem grande influência nas características geométricas do cordão de solda e de desempenho da soldagem. Para cada incremento de F provocou uma redução da largura do cordão de solda e aumento da penetração, altura do reforço, taxa de deposição e rendimento de deposição. O incremento Tp acarretou a formação de cordões mais largos, como também a redução na altura do reforço, penetração, taxa de deposição e rendimento de deposição. A variação de Ap não teve influência sobre largura do cordão, a altura do reforço, taxa de deposição e rendimento de deposição. / In the present work one searched to determine the behavior of the geometric characteristics of the bead weld and the performance of the welding, through the process self-shielded flux cored arc welding and pulsed current. The studied geometric characteristics had been width of bead, penetration of the weld, height of the reinforcement. To define the performance of the welding one analyzed the deposition efficiency and the deposition rate. As metal base was used steel ABNT 1010 with thickness 6, 35 mm. The used wire was the AWS E71T-11 with diameter 1,1 mm. The welds had been carried through by simple deposition, using themselves a microprocessed weld power source, remaining constant it welding speed and the stick-out. During the welding process the analyzed parameters of pulse had been the peak current (Ap), base current (Ab), pulse frequency (F) and peak duration (Tp). For collection of the data a plate of acquisition of data with interface to a microcomputer was used. Of ownership of the data, the ANOVA technique was applied, with the objective to identify, to quantify and to locate the significance of the dispersions. It was verified that the mean voltage has great influence in the geometric characteristics of the bead weld and the performance of the welding. For each increment of F it provoked a reduction of the width of the bead weld and increase of the penetration, height of the reinforcement, deposition rate and deposition efficiency. The Tp increment caused the wider bead weld formation, as also the reduction in the height of the reinforcement, penetration, deposition rate and deposition efficiency. The variation of Ap did not have influence on width of the bead weld, the height of the reinforcement, deposition rate and deposition efficiency.

O arame tubular AWS E71T-1 tem sido utilizado, na grande maioria das aplicaÃÃes, com CO2 e argÃnio. No entanto, para esta mistura de gÃs, as informaÃÃes nÃo foram levantadas, de forma suficiente, com relaÃÃo ao desempenho operacional do arame. Sabe-se que o tipo de gÃs afeta tambÃm a transferÃncia metÃlica, o comportamento do arco, a geometria do cordÃo de solda, a taxa de deposiÃÃo e a eficiÃncia de fusÃo do arame, dentre outras caracterÃsticas do processo de soldagem. O objetivo do trabalho consiste em realizar um levantamento das caracterÃsticas operacionais do arame tubular AWS E71T-1 empregando CO2 puro e uma mistura de CO2 + argÃnio na soldagem convencional em tensÃo constante e na soldagem com corrente pulsada. Neste sentido, foram realizadas soldas, com arame tubular AWS E71T-1 de 1,2 mm de diÃmetro, em simples deposiÃÃo, na posiÃÃo plana, em corpos de prova de aÃo ABNT 1020 com dimensÃes de 150x50x8 mm. Empregou-se uma fonte eletrÃnica de soldagem e um sistema automÃtico de posicionamento da pistola. A tensÃo de soldagem foi mantida em 23 V. A relaÃÃo entre a velocidade de alimentaÃÃo do arame e a velocidade de soldagem foi mantida entre 20 e 23, para garantir uma Ãrea adicionada aproximadamente constante de 18 mm2. analisaram-se os efeitos do tipo de gÃs de proteÃÃo (CO2 e Ar + CO2 ), da distÃncia bico de contato peÃa (20 e 25 mm), dos nÃveis de corrente (160, 180 e 200 A) e sua natureza (convencional e pulsada) sobre o comportamento do arco, sobre a geometria da solda e sobre as caracterÃsticas econÃmicas do arame (taxa de fusÃo, taxa de deposiÃÃo e eficiÃncia de deposiÃÃo). Os resultados indicam que o tipo de gÃs de proteÃÃo afeta mais significativamente a transferÃncia metÃlica e a geometria da solda, exercendo pequena influÃncia sobre as caracterÃsticas econÃmicas do arame. Constatou-se tambÃm que o efeito da intensidade de corrente sobre a operacionalidade do arame tubular AWS E71T-1 depende sensivelmente do tipo de corrente (convencional ou pulsada). / The flux cored wire AWS E71T-1 has been used in the vast majority of its applications with pure CO2 as a shielding gas. A recent study demonstrated that it is possible to improve the metallurgical characteristics of the weld metal of the flux cored wire by the application of a mixture of CO2 and argon. However, information for this gas mixture hasnât been raised sufficiently concerning the operational performance of the wire using this gas mixture. It is known that the gas type also affects the metal transfer, the behavior of arc welding, the weld bead geometry, the deposition rate and the deposition efficiency of the wire within other characteristics of the welding process. The aim of the study consists in the realization of a survey of the AWS E71T-1 flux cored wire operational characteristics (economic characteristics of the welding consumable, geometric weld characteristics, arc stability and metal transfer). Due to this, bead on plate welding was performed using the flux cored wire AWS E71T-1 with a diameter of 1,2 mm, in flat position on samples of ABNT 1020 steel with a size of 150x50x8 mm. An electronic welding source and a positioning system were used. It was sustained a welding tension of 23 V. The relationship between the wire feed speed and the travel speed was kept constant between 20 and 23 to guarantee a deposit area of approximately 18 mm2. The influence of shielding gas (CO2 and Ar and CO2 ), the contact tube-to-work (TTW) (20 and 25 mm), the welding current (160, 180 and 200 A) and its nature (conventional and pulsed) were analyzed regarding the behavior of arc welding, the weld geometry and the economic characteristics of cored wire (fusion rate, deposition rate and deposition efficiency). The results showed that the shielding gas type has more influence on metal transfer and welding geometry and little influence on economic characteristics of the cored wire. It was also shown that the effect of the current intensity on the operationally of the flux cored wire AWS E71T-1 depends perceptibly on the current type (conventional or pulsed).

Analysis of intersection crashes is a significant area in traffic safety research. This study contributes to the area by identifying traffic-geometric characteristics and driver demographics that affect different types of crashes at signalized intersections. A simple methodology to estimate crash frequency at intersections based on the size of the intersection is also developed herein. First phase of this thesis used the crash frequency data from 1,335 signalized intersections obtained from six jurisdictions in Florida, namely, Brevard, Seminole, Dade, Orange, and Hillsborough Counties and the City of Orlando. Using these data a simple methodology has been developed to identify the expected number of crashes by type and severity at signalized intersections. Intersection size, based on the total number of lanes, was used as a factor that was simple to identify and a representative of many geometric and traffic characteristics of an intersection. The results from the analysis showed that crash frequency generally increased with the increased size of intersections but the rates of increase differed for different intersection types (i.e., Four-legged intersection with both streets two-way, Four-legged intersection with at least one street one-way, and T-intersections). The results also showed that the dominant type of crashes differed at these intersection types and severity of crashes was higher at the intersections with more conflict points and larger differential in speed limits between major and minor roads. The analysis may potentially be useful for traffic engineers for evaluating safety at signalized intersections in a simple and efficient manner. The findings in this analysis provide strong evidence that the patterns of crashes by type and severity vary with the size and type of intersections. Thus, in future analysis of crashes at intersections, the size and type of intersections should be considered to account for the effects of intersection characteristics on crash frequency. In the second phase, data (crash and intersection characteristics) obtained from individual jurisdictions are linked to the Department of Highway Safety and Motor Vehicles (DHSMV) database to include characteristics of the at-fault drivers involved in crashes. These crashes are analyzed using contingency tables and binary logistic regression models. This study categorizes crashes into three major types based on relative initial movement direction of the involved vehicles. These crash types are, 1) Initial movement in same direction (IMSD) crashes. This crash type includes rear end and sideswipe crashes because the involved vehicles for these crashes would be traveling in the same direction prior to the crash. 2) Initial movement in opposite direction (IMOD) crashes comprising left-turn and head on crashes. 3) Initial movement in perpendicular direction (IMPD) crashes, which include angle and right-turn crashes. Vehicles involved in these crashes would be traveling on different roadways that constitute the intersection. Using the crash, intersection, and at-fault driver characteristics for all crashes as inputs, three logistic regression models are developed. In the logistic regression analyses total number of through lanes at an intersection is used as a surrogate measure to AADT per lane and also intersection type is introduced as a 'predictor' of crash type. The binary logistic regression analyses indicated, among other results, that at intersections with one-way roads, adverse weather conditions, older drivers and/or female drivers increase the likelihood of being at-fault at IMOD crashes. Similar factors associated with other groups of crashes (i.e., IMSD and IMPD) are also identified. These findings from the study may be used to develop specialized training programs by zooming in onto problematic intersections/maneuvers.

This thesis presents a model for the procedures of manufacturing Fused Fila ment Fabrication (FFF) components by calculating required process parameters using empirical equations. Such an empirical model has been required within the FFF field of research for a considerable amount of time and will allow for an ex pansion in understanding of the fundamental mathematics of FFF. Data acquired through experimentation has allowed for a data set of geometric characteristics to be built up and used to validate the model presented. The research presented draws on previous literature in the fields of additive manufacturing, machine engi neering, tool-path programming, polymer science and rheology. Combining these research fields has allowed for an understanding of the FFF process which has been presented in its simplest form allowing FFF users of all levels to incorporate the empirical model into their work whilst still allowing for the complexity of the process. Initial literature research showed that Polylactic Acid (PLA) is now in common use within the field of FFF and therefore was selected as the main working mate rial for this project. The FFF technique, which combines extrusion and Computer Aided Manufacturing (CAM) techniques, has a relatively recent history with lit tle understood about the fundamental mathematics governing the process. This project aims to rectify the apparent gap in understanding and create a basis upon which to build research for understanding complex FFF techniques and/or pro cesses involving extruding polymer onto surfaces.

L’émergence des matériaux composites dans le domaine aéronautique a permis d’alléger considérablement les structures. Cependant l’adaptation du processus d’assemblage aux contraintes imposées par la présence de ces matériaux n’est pas encore complète. De nombreuses opérations considérées comme non-productives sont nécessaires pour garantir le respect des nouvelles exigences. Dans le cadre du projet européen LOCOMACHS, l’utilisation d’un outil de simulation d’assemblage est envisagée afin de limiter le recours à ces opérations. Ces travaux s’inscrivent dans le cadre de la validation, par la mesure, des modèles utilisés pour la simulation d’assemblage flexible. Une méthode d’évaluation de la géométrie d’un composant souple est mise en œuvre afin de compenser par simulation numérique les effets de l’environnement sur le composant lors de sa mesure. Une analyse de sensibilité de la méthode aux variations des différents paramètres de mesure et de simulation est réalisée afin de définir un cadre pour la mise en œuvre. Une analyse modale des écarts à une géométrie de référence contribue à la correction de certains paramètres du modèle utilisé pour réaliser la compensation par simulation. Cette géométrie de référence est obtenue par une méthode de retournement appliquée dans un contexte flexible, afin d'annuler certains effets de l'environnement sur la géométrie mesurée du composant. Le jeu entre les composants assemblés est la caractéristique géométrique prépondérante dans un assemblage de structure aéronautique composite. La simulation d’assemblage, à partir des mesures réalisées sur les composants souples, permet d’évaluer le jeu entre les composants avant leur assemblage. Des méthodes de mesure de jeu dans un assemblage de composants souples sont proposées, et leur mise en œuvre expérimentale est réalisée. La confrontation des jeux mesurés et simulés permet de souligner d’une part les performances de l’outil de simulation, et d’autre part les difficultés liées à la modélisation des environnements de mesure et d’assemblage réels. / The emergence of composite materials in aeronautics leads to lighter structures. However, these new materials induce new constraints to the assembly process. The adaptation is not yet complete. Indeed many operations are necessary to respect the new requirements, but are considered as non-productive. In the context of the European project LOCOMACHS, an assembly simulation tool is developed to limit the use of these operations. This thesis relates to the validation, from the measure, of the models used for flexible assembly simulation. A method to evaluate the geometry of a flexible component is implemented. The method compensates, by simulation, the effects of the environment on the component during its measurement. A sensitivity analysis of the method against changes in various measurement parameters and simulation parameters is performed in order to define a framework for implementation. Parameters of the model used to perform the compensation by simulation are not representative of the actual behavior. A modal analysis of deviations to a chosen reference geometry contributes to the adjustment of these parameters. This reference geometry is obtained by a reversal method applied in a flexible context to cancel some of the effects of the environment on the measured geometry of the component. The gap between the assembled components is the geometric key characteristic in an assembly of aeronautical composite structure. The assembly simulation, from measuring data of flexible components, enables to evaluate the gap between the components prior to assembly. Gap measurement methods in an assembly of flexible components are proposed, and they have been experimentally performed. The comparison of measured and simulated gaps highlights the performance of the simulation tool, and the difficulties in modeling actual measurement environment and actual assembly environment.

The main role of roadway lighting is to produce quick, accurate and comfortable visibility during nighttime conditions. It is commonly known that good lighting levels enable motorists, pedestrians and bicyclists to obtain necessary visual information in an effective and efficient manner. Many previous studies also proved that roadway lighting minimizes the likelihood of crashes by providing better visibility for roadway users. Appropriate and adequate roadway lighting illuminance levels for each roadway classification and pedestrian areas are essential to provide safe and comfortable usage. These levels are usually provided by national, or local standards and guidelines. The Florida Department of Transportation (FDOT) Plan Preparation Manual recommends a roadway lighting illuminance level average standard of 1.0 horizontal foot candle (fc) for all the roadway segments used in this research. The FDOT Plan Preparation Manual also states that this value should be considered standard, but should be increased if necessary to maintain an acceptable uniformity illuminance ratio. This study aimed to find the relationship between nighttime crash injury severity and roadway lighting illuminance. To accomplish this, the research team analyzed crash data and roadway lighting illuminance measured in roadway segments within the West Central Florida Region. An Ordered Probit Model was developed to understand the relationship between roadway lighting illuminance levels and crash injury severity. Additionally, a Negative Binomial Model was used to determine which roadway lighting illuminance levels can be more beneficial in reducing the counts of crashes resulting in injuries. A comprehensive literature review was conducted using longitudinal studies with and without roadway lighting. Results showed that on the same roadways there was a significant decrease in the number of nighttime crashes with the presence of roadway lighting. In this research, roadway lighting illuminance was measured every 40 feet using an Advanced Lighting Measurement System (ALMS) on a total of 245 centerline miles of roadway segments within the West Central Florida Region. The data were mapped and then analyzed using the existing mile post. During the process of crash data analysis, it was observed that rear-end collisions were the most common first harmful event observed in all crashes, regardless of the lighting conditions. Meanwhile, the average injury severity for all crashes, was found to be possible injury regardless of the lighting conditions (day, dark, dusk, and dawn). Finally, this research presented an Ordered Probit Model, developed to understand the existing relationship between roadway lighting illuminance levels and injury severity within the West Central Florida Region. It was observed that having a roadway lighting average moving illuminance range between 0.4 to 0.6 foot candles (fc) was more likely to have a positive effect in reducing the probability of injury severity during a nighttime crash. A Negative Binomial Model was conducted to determine if the roadway lighting average moving illuminance level, found on the Ordered Probit Model was beneficial in reducing crash injury severity during nighttime, would also be beneficial in reducing the counts of crashes resulting in injuries. It was observed that a roadway lighting average moving illuminance, range between 0.4 to 0.6 fc, was more likely to reduce the count of crashes resulting in injuries during nighttime conditions, thus increasing roadway safety. It was also observed that other factors such as pavement condition, site location (intersection or no intersection), number of lanes, and traffic volume can affect the severity and counts of nighttime crashes. The results of this study suggest that simply adding more roadway lighting does not make the roadway safer. The fact is that a reduction in the amount of roadway lighting illuminance can produce savings in energy consumption and help the environment by reducing light pollution. Moreover, these results show that designing roadway lighting systems go beyond the initial design process, it also requires continuous maintenance. Furthermore, regulations for new developments and the introduction of additional lighting sources near roadway facilities (that are not created with the intent of being used for roadway users) need to be created.