Frictional requirements necessary to reduce skidding accident frequencies. Final report.

Federal Highway Administration, Washington, D.C.

The skidding of vehicles - a dynamic analysis. Progress report for the period September 1967-September 1968.

National Highway Safety Bureau, Washington, D.C.

Effects of Pavement Surface Texture on Noise and Frictional Characteristics HR-281, February 1987

An experimental modification of the transverse groove surface texture of a section of an urban interstate highway was performed by the Iowa Department of Transportation. Transverse groove texturing i s a design feature required by the Federal Highway Administration t o reduce skidding under wet pavement conditions. Adjacent residents claimed the texturing was the cause of especially annoying tonal characteristics within the traffic noise. A research proposal to modify the existing texture pattern by surface grinding and to study the noise and friction effects was approved for funding by the Iowa Highway Research Board. Results i n the form of a comparison between traffic noise before modification and traffic noise immediately after and 15 months after modification indicate that the change in surface texture has lowered overall traffic noise levels by reducing a high frequency component of the traffic noise spectrum. Fraffic testing data show reduced capacity of the roadway to inhibit wet pavement skidding as a result of the surface modification.

Tire traces: discrimination and classification of pyrolysis-GC/MS profiles

Tire traces can be observed on several crime scenes as vehicles are often used by criminals. The tread abrasion on the road, while braking or skidding, leads to the production of small rubber particles which can be collected for comparison purposes. This research focused on the statistical comparison of Py-GC/MS profiles of tire traces and tire treads. The optimisation of the analytical method was carried out using experimental designs. The aim was to determine the best pyrolysis parameters regarding the repeatability of the results. Thus, the pyrolysis factor effect could also be calculated. The pyrolysis temperature was found to be five time more important than time. Finally, a pyrolysis at 650 °C during 15 s was selected. Ten tires of different manufacturers and models were used for this study. Several samples were collected on each tire, and several replicates were carried out to study the variability within each tire (intravariability). More than eighty compounds were integrated for each analysis and the variability study showed that more than 75% presented a relative standard deviation (RSD) below 5% for the ten tires, thus supporting a low intravariability. The variability between the ten tires (intervariability) presented higher values and the ten most variant compounds had a RSD value above 13%, supporting their high potential of discrimination between the tires tested. Principal Component Analysis (PCA) was able to fully discriminate the ten tires with the help of the first three principal components. The ten tires were finally used to perform braking tests on a racetrack with a vehicle equipped with an anti-lock braking system. The resulting tire traces were adequately collected using sheets of white gelatine. As for tires, the intravariability for the traces was found to be lower than the intervariability. Clustering methods were carried out and the Ward's method based on the squared Euclidean distance was able to correctly group all of the tire traces replicates in the same cluster than the replicates of their corresponding tire. Blind tests on traces were performed and were correctly assigned to their tire source. These results support the hypothesis that the tested tires, of different manufacturers and models, can be discriminated by a statistical comparison of their chemical profiles. The traces were found to be not differentiable from their source but differentiable from all the other tires present in the subset. The results are promising and will be extended on a larger sample set.

Evaluation of the surface erosion from different timber yarding methods in Honduras

Surface runoff and sediment production from different timber yarding practices, some using Best Management Practices (BMPs) recommended for Honduras, were monitored in experimental plots during the rainy seasons of two consecutive years in pine forest highlands of central Honduras. Different timber yarding systems were applied to pseudo-replicated plots during the rainy seasons of 1999 and 2000. In 1999, two treatments were studied: tractor yarding and skyline cable (a recommended BMP). In 2000, four treatments were evaluated: tractor skidding, skyline cable, animal skidding (another recommended BMP), and undisturbed forest (reference). During the rainy seasons of these years, surface runoff volumes and sediment yield were measured at five 1.5m x 10m erosion plots in each treated area. The results showed significant differences between traditional tractor yarding and the recommended skyline cable and animal skidding methods. Tractor yarding produced six to ten times more erosion during the rainy seasons than cable and animal yarding. The improved soil retention of cable and animal yarding was especially important during September when the highest rainfall occurred in this climate.

Semeadora-adubadora: exigências em função do preparo do solo, da pressão de inflação do pneu e da velocidade

As semeadoras-adubadoras, responsáveis pela correta adição de semente e adubo ao solo, possuem mecanismos dosadores acionados por suas rodas motrizes, que giram em função do contato com a superfície do solo. Esse contato é influenciado, entre outros fatores, pela pressão de inflação dos pneus. O objetivo do presente trabalho foi estudar o desempenho de uma semeadora-adubadora de precisão em função do preparo do solo (preparo convencional e plantio direto), das velocidades de deslocamento e da pressão de inflação do seu pneu. O trabalho foi realizado na UNESP de Jaboticabal (SP) no ano de 2006. Foram avaliadas as seguintes variáveis: força de tração e potência na barra, consumo de combustível (horário, ponderal, operacional e específico), capacidade de campo operacional, patinagem dos rodados do trator e da semeadora-adubadora, estande inicial e distribuição longitudinal de sementes. O sistema plantio direto demandou maior força (35 %), potência e consumo horário de combustível; o mesmo aconteceu na maior velocidade. A pressão de inflação das rodas da semeadora proporcionou menor patinagem e maior estande inicial de plântulas.

Otimização da distância de extração de madeira com forwarder

The activities and management operations of wood harvesting do not have good computational tools available to help the forest technicians with the task of cost reduction. In many cases, machines of high investment are used in wood harvesting without adequate operation planning; consequently, the cost per hour of these machines, which is high, could be reduced. Using technological resources such as the Geographic Information Systems (GIS) integrated with the Global Positioning System (GPS), which are the basis of precision harvesting. In this research, a technological tool capable of calculating and optimizing the average skidding distance of the forwarder was developed. It was used in stands of different sizes and formats through mathematical techniques and available functionalities in the Geographic Information System GRASS. The developed tool, called optimized model, divides the stand in small parts in relation to shorter skidding distances. The main variable considered was the alignment of plantation. The model was tested in eucalypt stands located in the State of São Paulo. Sixteen stands were randomly selected: eight with a rectangular polygon form, and eight with irregular polygon form. The main variables were collected in these stands. Results showed that the optimized model developed, is efficient and flexible. It was possible to divide the stands in small parts resulting in smaller skidding medium distances. The stands with irregular form had shorter skidding medium distances than the rectangular stands.

Otimização da distância de extração de madeira com forwarder

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Estudo de diferentes sistemas de colheita de Eucalyptus Spp em área montanhosa

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Sistema de control de tracción y salida para un monoplaza de la Fórmula SAE

En este proyecto de final de carrera se detalla el proceso de diseño, fabricación, montaje y ajuste de un dispositivo electrónico que sirva como sistema de control de tracción de un vehículo y que acoplaremos sobre un monoplaza de carreras que participa en la competición Formula SAE. La Formula SAE (Society of Automotive Engineers - Sociedad de Ingenieros de Automoción), es una competición de coches de carreras monoplaza a nivel universitario que promueve el desarrollo de la ingeniera aplicada a la automoción. Se pretende que este libro sirva de guía para el correcto manejo y desempeño del sistema fabricado. Además se ha pretendido que su lectura resulte fácil y comprensible para que la persona que lea este libro sea capaz de entender el sistema realizado para así poderlo mejorar. Gracias a la colaboración entre la Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación (ETSIST) de la Universidad Politécnica de Madrid (UPM), la Escuela de Ingenieros Industriales de esta misma Universidad (ETSII) y el Instituto Universitario de Investigación del Automóvil (INSIA), se sientan las bases de una plataforma docente en la cual se posibilita la formación y desarrollo de un vehículo tipo formula que participa en la ya mencionada competición Formula SAE. Para ello, se formo en el 2003 el equipo UPMRacing, primer representante español en el evento. El equipo se compone de más de 50 alumnos de la UPM y del Máster de Ingeniería en Automoción del INSIA. Es por tanto, en el vehículo fabricado por el equipo UPMRacing, en el que se pretende instalar este sistema de control de tracción. El control de tracción es un sistema de seguridad del automóvil diseñado para prevenir la perdida de adherencia cuando alguna rueda presenta deslizamiento, bien porque el conductor se excede en la aceleración o bien porque el firme este resbaladizo. La unidad de procesamiento del sistema de control de tracción fabricado lee la velocidad de cada rueda del vehículo mediante unos sensores y determina si existe deslizamiento, en tal caso, manda una señal a la centralita para disminuir la potencia hasta que el deslizamiento disminuya a unos valores controlados. El sistema cuenta con un control remoto que sirve como interfaz para que el piloto pueda manejarlo. Por ultimo, el dispositivo es capaz de conectarse a un bus de comunicaciones CAN para configurar ciertos parámetros. El objetivo del sistema es, básicamente, hacer que el coche no derrape en aceleraciones fuertes; concretamente en las salidas desde parado y al tomar una curva, aumentando así la velocidad en circuito y la seguridad del piloto. ABSTRACT. The purpose of this project is to describe the design, manufacture, assembly and adjustment processes of an electronic device acting as the traction control system (TCS) of a vehicle, that we will attach to a single-seater competition formula SAE car. The Formula SAE (Society of Automotive Engineers) is a graduate-level singleseater racing car competition promoting the development of automotive applied engineering. We also intend this work to serve as a technical user guide of the manufactured system. It is drafted clearly and concisely so that it will be easy for all those to whom it is addressed to understand and subject to further improvements. The close partnership among the Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación (ETSIST), Escuela de Ingenieros Industriales (ETSII) of Universidad Politécnica de Madrid (UPM), and the Instituto Universitario de Investigación del Automóvil (INSIA), lays the foundation of a teaching platform enabling the training and development of a single-seater racing car taking part in the already mentioned Formula SAE competition. In this respect, UPMRacing team was created back in 2003, first spanish representative in this event. The team consists of more than 50 students of the UPM and of INSIA Master in Automotive Engineering. It is precisely the vehicle manufactured by UPMRacing team where we intend to install our TCS. TCS is an automotive safety system designed to prevent loss of traction when one wheel has slip, either because the driver exceeds the acceleration or because the firm is slippery. The device’s central processing unit is able to detect the speed of each wheel of the vehicle via special sensors and to determine wheel slip. If this is the case, the system sends a signal to the ECU of the vehicle to reduce the power until the slip is also diminished to controlled values. The device has a remote control that serves as an interface for the pilot to handle it. Lastly, the device is able to connect to a communication bus system CAN to set up certain parameters. The system objective is to prevent skidding under strong acceleration conditions: standing-start from the starting grid or driving into a curve, increasing the speed in circuit and pilot’s safety.

Pavement friction measurements on nontangent sections of roadways. Volume III. Appendices. Final report.

Federal Highway Administration, Structures and Applied Mechanics Division, Washington, D.C.

Pavement friction measurements on nontangent sections of roadways. Volume II: comprehensive report. Final report.

Federal Highway Administration, Structures and Applied Mechanics Division, Washington, D.C.

Validation of standard surface reproducibility. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Development of a wet weather safety index. Final report.

Texas State Department of Highways and Public Transportation, Austin

Tentative pavement and geometric design criteria for minimizing hydroplaning. Phase I. Final report.

Federal Highway Administration, Office of Research and Development, Washington, D.C.