This research develops transfer matrix model for the longitudinal vibratory component of a rotary-vibratory drilling (RVD) system driven with an electrohydraulic inertial mass exciter. The RVD system is a hybrid drilling system consisting of a conventional rotary drilling system assisted by forced harmonic vibrations. The model includes a drill string with continuously distributed inertia, stiffness, internal material, and external fluid damping. These properties were introduced through a new continuum transfer matrix for a damped pipe element. The model allows for the inclusion of realistic geometrical representations for the drill string, and the inclusion of masses, springs, dashpots, and other axial structural elements. The force exerted on the drill string by the drilling fluid was included using the theory of a flat plate oscillating in a newtonian fluid. The force had an inertia and a viscous damping component. These were incorporated into the inertia and external fluid damping terms in the new continuum transfer matrix. The exciter had force and power limits. The rock-rock bit boundary was represented as a structurally damped spring. / Ph. D.

This study was an experimental design, using twenty-two variables, twelve covariates, and six criterion measures. The purpose of the study was the effect of the use of selected transcription drills in beginning shorthand on the ability of students to produce both typewritten copy and mailable letters from shorthand notes. The bases for comparison were five minute timed transcription tests, three-minute dictation tests, and thirty-minute mailable letter production tests, of both previewed and unpreviewed material.

In the aerospace industry, burr removal is a very important part of the manufacturing process. Stacks of material on sections of an aircraft are assembled and drilled by hand. Due to extensive burr formation the sheets must be destacked so that burrs can be removed and then the stacks are reassembled and fastened together. If burrs are minimized in the drilling process, this would reduce the necessity for the sheets to be destacked and deburred. One approach to minimizing burrs is to lower the thrust force in drilling through suitable modification of the drill geometry such as the use of a step drill. Although prior researchers have analyzed different drill geometries such as step drills and their effect on hole exit burr formation in the drilling process through experimentation, no work has been reported on modeling and analysis of step drilling forces and their relationship to burr formation as a function of the step drill geometry parameters. Consequently, this thesis focuses on the modeling of the thrust force and torque for step drills and analyzes their relationship with burr size as a function of the step drill geometry parameters. In the first step, a mechanistic model for thrust and torque in drilling is implemented for a standard twist drill. This mechanistic model is then adapted to predict the thrust and torque for a step drill. Subsequently, experiments are performed to validate the mechanistic model and to evaluate burr formation with standard and step drills. The influence of thrust and torque on hole exit burr formation is analyzed for different step drill geometries and experimental feeds and speeds. The results show that the predicted thrust and torque values for both drill geometries are in good agreement with measured values, although the torque model consistently underpredicts. For standard drill geometry in the calibration tests, the average error in the thrust prediction is 7.09% and the average error in the torque prediction is -18.05%. In validation tests, the average error for predicted thrust is 2.29% and the average error for predicted torque is -18.46%. For the step drill model the average error in thrust is 0.72% while the average error in torque is -8.72%. In addition, a reduction in the predicted thrust force for a step drill relative to the standard twist drill is found to correlate well with a reduction in the measured burr size. However, further reduction in the thrust force by varying the step angle and diameter ratio do not correlate well with the measured burr size. Likely reasons for these results are presented in this thesis.

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Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1921. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed May 13, 2009)

Thesis (doctoral)--Helsinki University of Technology, 2005. / Includes bibliographical references. Also available on the World Wide Web. Myös verkkojulkaisuna.

Made available in DSpace on 2014-06-11T19:24:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-07-29Bitstream added on 2014-06-13T19:31:43Z : No. of bitstreams: 1 correia_tps_me_botfca.pdf: 505653 bytes, checksum: 7f4cab535edd45af40fd0c7c4750339f (MD5) / Uma opção para a semeadura correta da cultura do sorgo é com o uso de semeadoras-adubadoras de fluxo contínuo. Com estas máquinas é possível realizar a regulagem da deposição e distribuição de sementes, e o conhecimento do seu desempenho nas mais diversas condições de trabalho. Existem condições com declives plano e ondulado, desta maneira a deposição das sementes por semeadoras-adubadoras de fluxo-contínuo podem ser prejudicadas. Sendo assim, o objetivo deste trabalho foi avaliar em simulador o comportamento da deposição de sementes por um mecanismo dosador de fluxo contínuo em condições distintas de relevo do terreno, velocidade de semeadura e quantidade de sementes no reservatório, assim como avaliar a qualidade das sementes depositadas. O trabalho foi realizado em duas etapas, na Fundação Agrária de Pesquisa Agropecuária – (FAPA) e na Faculdade de Ciências Agronômicas da UNESP de Botucatu – SP. A primeira etapa foi a coleta de sementes no simulador utilizando um mecanismo dosador do tipo rotor acanalado helicoidal de fluxo contínuo operando transversalmente ao declive, e a segunda foi a realização das análises de qualidade das sementes coletadas na primeira etapa. O delineamento experimental do ensaio foi avaliado em esquema fatorial simples trabalhando-se com três fatores (três relevos x três velocidade; três relevos x três nível do reservatório de sementes; e três velocidade x três nível do reservatório de sementes). As análises estatísticas foram realizadas utilizando o programa SAS, sendo os dados submetidos ao teste de Tukey e as médias comparadas pelo teste F ao nível de 5 % de significância. Os resultados obtidos mostraram que a elevação da velocidade de trabalho reduz a deposição de sementes no relevo com 3%. Os relevos com 8% e 16% propiciam redução... / One option for sowing and correct plantability of sorghum is using seeder streaming. With these machines it is possible to perform precise adjustment of the deposition and distribution of seeds and knowledge of its performance in various conditions. In various national regions producing sorghum, there are conditions with steep slopes, thus the plantability seed by seeder-continuous flow may be impaired. Thus, the aim of this study was to evaluate the behavior of the simulator seed deposition by a continuous flow metering system in different conditions of slope, seeding speed and level of the reservoir, as well as assess the quality of seeds deposited. The study was conducted in two stages, the Agrarian Foundation for Agricultural Research - (FAPA) and the Faculty of Agricultural Sciences, UNESP, Botucatu– SP. The first step was the simulation of a seeder streaming operating across the slope, and the second was the analyzes of quality seeds collected in the first stage. The experimental test was being evaluated in randomized factorial design simple by working with three parts (three x three-speed slope, three x three slope reservoir level seed and three x three slope reservoir level seed).Statistical analyzes were performed using SAS software, the data being tested for Tukey and means were compared by F test at 5% level of significance. The results showed that the increase in operating speed reduces the deposition of seeds in the flat slope. The gentle slopes and undulating wavy provide reduction of seed deposition. The deposition rate was achieved more precisely seeds with a slope up and the working speed of 4 km h-1, and the lowest... (Complete abstract click electronic access below)

Orientador: Carlos Antonio Gamero / Coorientador: Paulo Roberto Arbex Silva / Banca: Kléber Pereira Lanças / Banca: Carlos Eduardo Angeli Furlani / Resumo: Uma opção para a semeadura correta da cultura do sorgo é com o uso de semeadoras-adubadoras de fluxo contínuo. Com estas máquinas é possível realizar a regulagem da deposição e distribuição de sementes, e o conhecimento do seu desempenho nas mais diversas condições de trabalho. Existem condições com declives plano e ondulado, desta maneira a deposição das sementes por semeadoras-adubadoras de fluxo-contínuo podem ser prejudicadas. Sendo assim, o objetivo deste trabalho foi avaliar em simulador o comportamento da deposição de sementes por um mecanismo dosador de fluxo contínuo em condições distintas de relevo do terreno, velocidade de semeadura e quantidade de sementes no reservatório, assim como avaliar a qualidade das sementes depositadas. O trabalho foi realizado em duas etapas, na Fundação Agrária de Pesquisa Agropecuária - (FAPA) e na Faculdade de Ciências Agronômicas da UNESP de Botucatu - SP. A primeira etapa foi a coleta de sementes no simulador utilizando um mecanismo dosador do tipo rotor acanalado helicoidal de fluxo contínuo operando transversalmente ao declive, e a segunda foi a realização das análises de qualidade das sementes coletadas na primeira etapa. O delineamento experimental do ensaio foi avaliado em esquema fatorial simples trabalhando-se com três fatores (três relevos x três velocidade; três relevos x três nível do reservatório de sementes; e três velocidade x três nível do reservatório de sementes). As análises estatísticas foram realizadas utilizando o programa SAS, sendo os dados submetidos ao teste de Tukey e as médias comparadas pelo teste F ao nível de 5 % de significância. Os resultados obtidos mostraram que a elevação da velocidade de trabalho reduz a deposição de sementes no relevo com 3%. Os relevos com 8% e 16% propiciam redução... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: One option for sowing and correct plantability of sorghum is using seeder streaming. With these machines it is possible to perform precise adjustment of the deposition and distribution of seeds and knowledge of its performance in various conditions. In various national regions producing sorghum, there are conditions with steep slopes, thus the plantability seed by seeder-continuous flow may be impaired. Thus, the aim of this study was to evaluate the behavior of the simulator seed deposition by a continuous flow metering system in different conditions of slope, seeding speed and level of the reservoir, as well as assess the quality of seeds deposited. The study was conducted in two stages, the Agrarian Foundation for Agricultural Research - (FAPA) and the Faculty of Agricultural Sciences, UNESP, Botucatu- SP. The first step was the simulation of a seeder streaming operating across the slope, and the second was the analyzes of quality seeds collected in the first stage. The experimental test was being evaluated in randomized factorial design simple by working with three parts (three x three-speed slope, three x three slope reservoir level seed and three x three slope reservoir level seed).Statistical analyzes were performed using SAS software, the data being tested for Tukey and means were compared by F test at 5% level of significance. The results showed that the increase in operating speed reduces the deposition of seeds in the flat slope. The gentle slopes and undulating wavy provide reduction of seed deposition. The deposition rate was achieved more precisely seeds with a slope up and the working speed of 4 km h-1, and the lowest... (Complete abstract click electronic access below) / Mestre

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