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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Caracterização de payloads via telemetria

Teixeira, Lucas Augusto Costa January 2016 (has links)
O preço atual do minério de ferro obrigou as empresas a reduzirem os custos operacionais na fase mina. O carregamento e transporte de materiais com utilização de escavadeiras e caminhões grande porte representam grande parcela do custo total, particularmente com pneus, diesel, manutenção e mão de obra. Metas de movimentação anual são divididas durante os meses e as condições climáticas podem influenciar na produtividade e desempenho dos equipamentos. O banco de dados da movimentação mensal está condicionado com a capacidade de cada caminhão. Cada frota possui o payload característico e este representa a capacidade de transporte, sendo o valor da massa transportada o único parâmetro extraído em cada ciclo, sem considerar o posicionamento do material sobre a caçamba dos equipamentos. Forças de cisalhamento e torção são aplicadas constantemente no chassi e pneus dos caminhões e, quando as cargas estão descentralizadas, potencializam estes eventos. O transporte de cargas descentralizadas agride os pneus diminuindo a vida útil causando danos como deslocamento da banda de rodagem e separação do flanco. Este trabalho teve como objetivo diminuir as ocorrências de cargas descentralizadas e os custos operacionais. Para incrementar o posicionamento do material sobre as caçambas, a telemetria foi a ferramenta utilizada. Análises de pressões de suspensões indicam o posicionamento das cargas e através desses valores foi criado um banco de dados. Este banco de dados pode indicar qual operador de carga precisa de reciclagem, contribuindo para a redução de cargas descentralizadas e custos, uma vez que cargas deste perfil sucateiam precocemente pneus e suspensões. O estudo foi realizado em Itabira, em uma mina de minério de ferro a céu aberto. A metodologia comprovou ser capaz diminuir as ocorrências de cargas descentralizadas assim como aumentar a vida útil de pneus. Uma possível economia foi apresentada para ano de 2014, período em que a média das horas trabalhadas de pneus ficou abaixo da meta aumentando os custos fase mina. / The actual iron ore price forces the companies to reduce costs in all production steps of the mining operation. Loading and hauling materials using shovel-truck system represents the highest mining costs, particularly tires, diesel, maintenance and workforce. Annual goals of materials movement are split by months were weather conditions can affect productivity and performance of the fleet. The data file of the monthly material movement is based on the scale of each truck. Every fleet has a payload and it represents the capacity of hauling, being the value of loading a unique input extracted in each duty cycle, without taking into account the position of the material over the truck’s dump. Shear forces and torsion are applied all time at the frames trucks and, when the truckloads are unbalanced, increases the forces over the frame and tires. Transport unbalanced truckloads into long distances attack the tires and decrease its end of life, causing damages like displacement of tread and flank separation. The objective of this study is to propose a methodology to decrease unbalanced truck loads reducing the mining costs. In this mission of incorporating a material position on the truck´s dump, the telemetry was taking into consideration. The analysis of the suspension pressures data values shows the truckloads positions and with this data was created a databank. This databank indicates that the operators need truck load training to reduce unbalanced loads and truck costs in the mining operation, since unbalanced loads leads to early tires and suspensions scrap. The case study was carried out at Itabira Iron Ore Mine Complex, Brazil. This methodology was able to reduce the number of unbalanced truck loads as well as the tires life was increased. An economic saving estimate is presented based on 2014 scrapped tires data bank, in this year the tires life cycle was underneath, burdening operational costs.
292

An investigation into the factors affecting the behaviour of Highway Filter Drains, with a particular emphasis on the Scottish Trunk Road Network

Mitchell, Ged January 2017 (has links)
Approximately 1500 km (43%) of the strategic Scottish trunk road network drainage asset takes the form of Highway Filter Drains (HFDs). However, despite their popularity, they are prone to clogging, therefore they have an estimated operational life-cycle of ten-years. This research was undertaken to investigate the complex inter-relationship between catchment characteristics, road dynamics and the physical characteristics of the road to establish the key factors that govern the generation and spatial variability of Road-Deposited-Sediment (RDS). The aim being to establish the impact RDS Particle Size Distribution (PSD) has on clogging and the operational life-cycle of HFDs. The research adopted an integrated approach, incorporating: (i) a Field Study to investigate RDS PSD grading envelopes across the Scottish trunk road network, (ii) a HFD Field Survey (HFD-FS) to investigate the current condition of HFDs across a range of catchments, (iii) a HFD Field Study to establish whether, or not, graded stone PSD envelopes comply with specification requirements when first placed in the trench, (iv) 3 HFD Field Studies to assess the level of risk of system failure through evaluating the causes and quantifying the individual, cumulative and influencing factors which contribute to the evolution of clogging in HFDs, and (v) a Field Study utilising Ground Penetrating Radar data to explore why stratified (clogged) layers evolve within some HFDs. Based on the results of this research, design and maintenance procedures were then identified to improve the performance of HFDs. Results established that Scottish trunk roads operate under variable catchment characteristics and road dynamics, with the condition and specification of the road surface, volume of traffic, road geometry, number of running lanes and adjacent land use governing the generation and spatial variability of RDS. Five of the nine trunk road RDS PSD profiles shared a peak particle diameter of 425 μm, two had a peak of 600 μm, one had a peak of 1180 μm and one resulted in a peak of 2120 μm. Particles >1000 μm were mostly mineral or asphalt and it was shown that there is a direct link between the factors that govern the generation and spatial variability of RDS and those that govern the evolution of clogging and actual operational life-cycle of HFDs. The HFD-FS revealed that 69% were assigned Filter Drain Condition Index ratings of 3 or below, which identifies these as having exceeded the ten-year estimated operational life-cycle. 94% of those deemed to have reached the end of their operational life-cycle were over-the-edge (OTE) HFDs, which supports the assertion that pre-treatment would increase their operational life-cycle. Results also established that introducing a kerb-line and gully-pots or grass-strip between the road and the HFD significantly reduced the indices of particle size composition d50 and d90 and percentage of RDS retained at depths spanning 0 - 400 mm, compared to OTE HFDs with comparable catchment characteristics and road dynamics. Based on these results, the operational life-cycle of HFDs with a kerb-line and gully-pots and OTE HFDs with a grass-strip can be expected to exceed twenty-years, if catchment characteristics and road dynamics are representative of those in this study. This research also identified that compacting Type B graded stone with ‘heavy vibrating machinery’ during construction could potentially contribute to clogging. It was also established that HFD harrowing may exacerbate clogging because the process of disintegrating the cake-layer mobilises an otherwise rigid and compacted RDS mass and this is more likely to penetrate deeper into the HFD and inundate the HFD during a storm event. These findings indicate that current HFD construction and maintenance practice could have a detrimental impact on the effective operational life-cycle of HFDs. Overall, this research study has demonstrated that there are considerable uncertainties related to PSD grading envelopes and percentage of RDS migrating from roads to HFDs. It is clear therefore that one of the most notable findings of this research is that given the scale of strategic trunk road networks, assuming a single HFD operational life-cycle profile, for a trunk road or trunk road network, is highly unlikely to be representative of a HFD at the local level. It follows then that the widely accepted estimated ten-year operational life-cycle for HFDs, does not reflect the actual operational life-cycle of HFDs.
293

Influência de medidas de segurança de trânsito no comportamento dos motoristas

Bottesini, Giovani January 2010 (has links)
Os acidentes de trânsito são uma das principais causas de morte e invalidez no mundo inteiro, e projeções indicam que sua participação entre essas causas tende a aumentar no futuro. Estima-se que o fator humano contribua para a ocorrência de mais de 90% dos acidentes, e grande parte desta contribuição advém do comportamento. Nesta dissertação de mestrado, buscou-se identificar e caracterizar medidas de segurança de trânsito conforme sua influência em inibir o cometimento de infrações à legislação de trânsito por parte dos motoristas. Para tanto, foram conduzidas uma pesquisa qualitativa e uma pesquisa quantitativa. A pesquisa qualitativa, realizada através da técnica de Grupos Focados, foi utilizada para identificar as principais infrações de trânsito que contribuem para a ocorrência de acidentes, além de coletar subsídios para a elaboração da pesquisa quantitativa. Esta, por sua vez, consistiu na aplicação de um questionário auto-relatado a motoristas de automóvel da cidade de Porto Alegre. Como resultado, a pesquisa qualitativa indicou que as infrações que mais contribuem para os acidentes são a embriaguez, o excesso de velocidade e o avanço de sinal vermelho de semáforo. A pesquisa quantitativa permitiu concluir que as medidas de segurança de trânsito que mais influenciam os motoristas a não cometerem infrações de trânsito são aquelas relacionadas à restrição de direitos, como apreensão do veículo ou suspensão da habilitação, e à possibilidade de ser flagrado pelas autoridades. Por outro lado, as campanhas de conscientização na mídia demonstraram ser o tipo de medida com menor potencial para influenciar o comportamento dos motoristas. / Road traffic crashes are one of the main causes of death and disability worldwide, and it is believed that their share among these causes will grow in the future. The human factor contributes to over 90% of traffic crashes, and a great part of this contribution originates from human behaviour. This master’s thesis aimed to identify and characterize road safety measures according to their influence on driver behaviour, regarding the commitment of traffic offences. In order to do that, a qualitative and a quantitative survey were carried on. The qualitative survey was made with the Focus Group technique and was used to identify the traffic offences that contribute the most to road crashes, as well as to collect information to help preparing the quantitative survey. The last consisted in applying a self-reported questionnaire to automobile drivers from Porto Alegre, Brazil. As a result, the qualitative survey indicated that speeding, drunk driving and red light crossing are the traffic offences that contribute the most to road crashes. The quantitative survey allowed to conclude that the road safety measures with more influence on drivers, so they do not commit traffic offences, are those related to their rights restriction, like vehicle seizure or driver’s licence suspension, and to the possibility of being caught by authorities. On the other hand, road safety campaings on the media seemed to be the kind of measure with the smallest potential to influence driver behaviour.
294

Análisis y propuesta de mejora de la seguridad vial en la carretera Panamericana Norte, tramo variante de Pasamayo del km 55 al km 70 aplicando la metodología del manual de seguridad vial

Guevara Delgado, Percy Jose Manuel, Norabuena Ita, Jherson Daniel 27 September 2019 (has links)
Entre los años 2015 y 2017 se aprecia el incremento de accidentes de tránsito en la red vial no urbana (carreteras), debido probablemente debido al aumento del flujo vehicular, el deficiente diseño geométrico, el deterioro y falta de mantenimiento de la vía. El tramo Variante de Pasamayo de la carretera PE-1N correspondiente a la Red Vial N° 5, no está excluida de este cambio, observándose como los accidentes de tránsito se han incrementado en esta vía. Debido a esta problemática es necesario determinar que herramientas de seguridad vial son necesarias implementar en la carretera Variante de Pasamayo para reducir la frecuencia de accidentes de tránsito. Esta investigación está enfocada en el análisis y propuestas de mejora de la Seguridad Vial en la Variante de Pasamayo aplicando la metodología de Inspección de Seguridad Vial (ISV) y el Método Predictivo del Highway Safety Manual (HSM) de acuerdo al nuevo Manual de Seguridad Vial (2017). La aplicación de la metodología de la Inspección de Seguridad Vial dio como resultado la identificación de tramos de concentración de accidentes los cuales son: Tramo I (Km 67+500 al Km 68+500) y el Tramo II (Km 68+500 al Km 69+500). Una vez identificados los tramos de concentración de accidentes, se procedió a utilizar el método predictivo del HSM para predecir la frecuencia de accidentes primero en las condiciones reales y luego analizando el tramo con las mejoras planteadas. Las propuestas de mejora para el Tramo I analizado son la ampliación de la berma a 3 metros, la implementación de bandas sonoras transversales y la implementación de barreras de contención. Mediante el análisis de efectividad de las mejoras de seguridad vial propuestas con el método predictivo del HSM se obtuvo una reducción del 56% de la frecuencia de accidentes. Se recomienda para futuras investigaciones que la información estadística de los accidentes registrados por la Policía Nacional sea más específica y detallada para poder utilizar correctamente el método predictivo del HSM. / This research is focused on the analysis and improvement proposals in the Pasamayo Variant (Lima), applying the Road Safety Inspection (ISV) methodology and the Highway Safety Manual (HSM) Predictive Method according to the new Safety Manual Road (2017). Where the application of road safety inspection includes the identification of the various areas where road safety is potentially poor due to various conditions and characteristics, according to a format that the manual itself, we provide and then statistical processes to determine the precise stretches of accident. Also the Manual of safety of the predictive method of the road (HSM), which involves the collection and processing of accidents originated and subscribed in the studied section in a period of approximately three years, the content, classification of vehicular traffic is also analyzed ( IMDA) and the lifting of geometric characteristics; with the objective of finding, in the first place: The prediction of the average frequency of expected accidents (Nesperado) with the current conditions of the site; Finally, the HSM is used to carry out a second prediction in which the road conditions have been changed with improvement proposals with the aim of reducing the percentage of expected accidents. The Road Safety Inspection Application and the Road Safety Manual, as it is called the identification of those areas where road safety has deficiencies and intervention is necessary in order to preserve the safety status of people. Finally, it should be mentioned that this research is a methodology that is not known in Peru, which should be implemented before, during and after the process of construction of a road in order to reduce the victims of traffic accidents. / Tesis
295

Prehospital Staffing and Road Traffic Accidents: Physician Versus Trained Nonphysician Responders

Grant, Timothy A. 01 January 2015 (has links)
Road traffic deaths, which affect people in their productive years, are projected to be the third leading cause of death by the year 2030. While most studies have focused on road infrastructure and vehicle safety, this study examined something new: the impact of prehospital response to road traffic accidents on the rate of death. Some countries send physicians to the scene of an accident; some send paramedics or registered nurses. The question this research sought to answer was whether the use of physician responders resulted in a lower rate of death compared to the use of nonphysician responders. The literature makes it clear that rate of road traffic death is related to country income and governance indicators, so first those variables needed to be equalized. My conceptual framework for this cross-sectional correlation study was the Haddon matrix, which organizes injuries by temporal (pre-event, event, and postevent) and epidemiological (host, agent, and environment) factors. Using World Health Organization data on road traffic injury and country income, World Bank data on governance indicators, and a literature search of 67 countries' prehospital response profiles, significant negative correlations (p > 0.001) were found for road traffic deaths and income, r (65) = -0.68, and governance indicators, r (65) = -0.646. No significant difference in the rate of road traffic death was found between physician and nonphysician prehospital staffing. Because increasing countries' income and improving governance are long-term, ambitious goals for developing countries, training nonphysician prehospital responders appears to be the most effective social change to decrease the burden of road traffic deaths.
296

THE GRANDEST IMPROVEMENT IN THE COUNTRY: AN HISTORICAL AND ARCHAEOLOGICAL STUDY OF THE GREAT NORTH ROAD, N.S.W., 1825-1836

KARSKENS, Grace January 1985 (has links)
The line of road originally intended to link Sydney with the booming settlements of the Hunter Valley underwent a ten year survey and construction period, beginning in 1825 with Heneage Finch's hastily selected, winding line, and ending in 1836 with two small road gangs caught in a continuous cycle of construction and decay. In the interim period, however, the road had aroused the enthusiasm of the best surveyors and engineers available in the colony. These men envisioned a fine, all-encompassing, permanent thoroughfare - a most appropriate goal in view of the contemporary optimism with regard to the colony's future. The structures and formations were impressive and etensive and built as far as possible according to the latest principles emerging from the road building revolution in Britain. The methods were, of necessity, simplified in response to the colonial conditions of rugged terrain, vast distances and the large but unskilled and, for the main part, unwilling convict labour force. The results were highly successful, as is stille vident today, and never failed to impress early travellers and reassure them that they were, after all, in a 'civilised' country. The road never actually fulfilled its builders' plans. A steamboat service established between Sydney and the Hunter Valley robbed it of its role as a vital link, and other more hospitable or more direct routes were discovered and used by what traffic did proceed on land. After the few remaining gangs were finally withdrawn, seciton after section quickly fell into disuse and abandonment. Both the grand and modest structures and formations were left neglected, and thus preserved, to the present day.
297

Forecasting Pavement Surface Temperature Using Time Series and Artificial Neural Networks

Hashemloo, Behzad 09 June 2008 (has links)
Transportation networks play a significant role in the economy of Canadians during winter seasons; thus, maintaining a safe and economic flow of traffic on Canadian roads is crucial. Winter contaminants such as freezing rain, snow, and ice cause reduced friction between vehicle tires and pavement and thus increased accident-risk and decreased road capacity. The formation of ice and frost caused by snowfall and wind chill makes driving a very difficult task. Pavement surface temperature is an important indicator for road authorities when they are deciding the optimal time to apply anti-icer/deicer chemicals and when estimating their effect and the optimal amounts to apply. By forecasting pavement temperature, maintenance crews can figure out road surface conditions ahead of time and start their operations in a timely manner, thereby reducing salt use and increasing the safety and security of road users by eliminating accidents caused by slipperiness. This research investigates the feasibility of applying simple statistical models for forecasting road surface temperatures at locations where RWIS data are available. Two commonly used modeling techniques were considered: time-series analysis and artificial neural networks (ANN). A data set from an RWIS station is used for model calibration and validation. The analysis indicates that multi-variable SARIMA is the most competitive technique and has the lowest number of forecasting errors.
298

Forecasting Pavement Surface Temperature Using Time Series and Artificial Neural Networks

Hashemloo, Behzad 09 June 2008 (has links)
Transportation networks play a significant role in the economy of Canadians during winter seasons; thus, maintaining a safe and economic flow of traffic on Canadian roads is crucial. Winter contaminants such as freezing rain, snow, and ice cause reduced friction between vehicle tires and pavement and thus increased accident-risk and decreased road capacity. The formation of ice and frost caused by snowfall and wind chill makes driving a very difficult task. Pavement surface temperature is an important indicator for road authorities when they are deciding the optimal time to apply anti-icer/deicer chemicals and when estimating their effect and the optimal amounts to apply. By forecasting pavement temperature, maintenance crews can figure out road surface conditions ahead of time and start their operations in a timely manner, thereby reducing salt use and increasing the safety and security of road users by eliminating accidents caused by slipperiness. This research investigates the feasibility of applying simple statistical models for forecasting road surface temperatures at locations where RWIS data are available. Two commonly used modeling techniques were considered: time-series analysis and artificial neural networks (ANN). A data set from an RWIS station is used for model calibration and validation. The analysis indicates that multi-variable SARIMA is the most competitive technique and has the lowest number of forecasting errors.
299

Traffic Sign Recognition For Unmanned Vehicle Control

Havur, Mehmet Bulent 01 November 2006 (has links) (PDF)
In this thesis, video frames acquired by a camera in a moving car are processed for detection of candidates of triangular, rectangular and circular traffic/road signs based on mainly shape information by performing contour analysis. Color information is utilized as an auxiliary method to improve detection. Then recognition based on template matching is realized on detected traffic/road sign candidates. Detection and recognition results of traffic/road signs in video frames taken in different time intervals of day for these methods are compared. After implementation, results show that the video scene taken in a sunny day in the afternoon gives better results than others. Binary threshold plays a great role in detection with respect to Canny edge detector especially for triangular and rectangular traffic signs. Higher number of binary threshold levels improves detection in general. In addition, the recognition rate for triangular and rectangular traffic/road signs is higher than that of circular sings in general by the methods used in this study.
300

Local Reactions To A National Road Project: The Case Of Black Sea Coastal Road Project, Turkey

Karatas, Sibel Esra 01 December 2006 (has links) (PDF)
The main purpose of this study is to understand the mobilization dynamics and impacts of the environmental opposition movement against the Black Sea Coastal Road Project in Turkey. The study is original in the sense that for the first time an opposition movement against a national road project was realized in Turkey. The Black Sea Coastal Road Project is one of the main infrastructure investments in Turkey. It covers a large geographical area, Eastern Black Sea Region, and some districts/provinces in the region formed an opposition movement against the project which objected to sea-filling method and destruction of coasts. The fieldwork of the study was conducted in seven districts/provinces of Eastern Black Sea Region. They were investigated in terms of their mobilization dynamics, tactics and the outcomes of the opposition movement. The main analysis is based on an evaluative approach and qualitative research. The fieldwork of the study was conducted in the periods of March 16, 2002 to March 24, 2002 and April 13, 2006 to April 20, 2006. In-depth-interviews and focus groups with local activists are used as data collection techniques. The seven cases-regions displayed some differences in their opposition movement in terms of the mobilization, tactics and the outcome. In the districts, most crucial for mobilization were the political party affiliation and the economic opportunity structures. The project being a part of governmental policy and the perception by the public, living in the region that the road is needed strongly affected dynamics, tactics and outcomes of the movement.

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