Typescript (photocopy). / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1984 B58 / Master of Science

Call number: LD2668 .T4 1986 F86 / Master of Science / Mechanical and Nuclear Engineering

Resumo: Esse trabalho foi realizado com o objetivo de comparar o desempenho de um trator equipado com pneus diagonais novos e pneus diagonais desgastados, em três condições de superfície: pista com solo mobilizado, pista com cobertura vegetal e pista com solo firme. Foi utilizado o delineamento experimental em faixas, sendo que em cada faixa (pista) foram dispostos os tratamentos em blocos ao acaso, com um arranjo fatorial de 2x4, definidos pelos dois conjuntos de pneus diagonais (novos e desgastados) e quatro condições de deslocamento, distinguidas pela mudança de marcha do trator, totalizando oito tratamentos, com três repetições cada, perfazendo 72 unidades experimentais. Foram coletados os dados para o cálculo da velocidade de deslocamento, patinagem das rodas traseiras e dianteiras do trator e consumo horário de combustível. Também foram coletados os dados de força de tração, sendo calculada a potência disponível na barra de tração em função da velocidade de deslocamento. Foi utilizado como carro dinamométrico a Unidade Móvel de Ensaio na Barra de Tração - UMEB, pertencente ao Núcleo de Ensaios de Máquinas e Pneus Agroflorestais - NEMPA, do Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas - FCA da UNESP, Campus de Botucatu - SP. Os resultados mostraram que tanto as condições dos pneus quanto as condições do solo interferiram na capacidade do trator em desenvolver força de tração, sendo o 2 pior desempenho obtido na pista com solo mobilizado. O melhor desempenho do trator foi na pista com solo firme; porém, na pista com cobertura vegetal ocorreram as melhores condições de força de tração do trator em relação ao solo mobilizado, mostrando que a presença da cobertura vegetal entre o rodado e o solo interferiu diretamente na relação rodado/solo. Na pista com solo mobilizado os resultados mostraram que a velocidade foi a menor... (Resumo completo, clicar acesso eletrôncio abaixo) / Abstract: The objective of this work was to compare the performance of a tractor equipped with used and new bias-ply tires, operating in three surface conditions: tillage soil, vegetal covered soil and firm soil. The experimental design were tracks and, in each track, treatments were disposed in blocks to the chance in a 2x4 factorial arrangement, defined by the two groups of tires (used and new bias-ply) and four speed conditions, distinguished by tractor’s gear change, totaling eight treatments, with three repetitions each, completing 72 experimental units. There were collected data to calculate: speed, front and rear tires slippage and fuel consumption. There were also collected data of traction strength to calculate available power at traction bar versus speed. The dynamometric car used was the Mobile Drawbar Test Unit - UMEB, owned by the Facility of Agricultural and Forestry Tires and Machines Assays (NEMPA) of Rural Engineering Department in the Agronomics Science College - FCA, UNESP, Botucatu campus. Results showed that both, tires and soil conditions, changed tractor capacity on developing traction strength. The worst performance was observed on the tillage soil. On the track with soil covered with vegetal residues, occurred better tractor traction strength conditions than on track with tillage soil, showing the presence of vegetal cover between tire and soil interfered directly on the tires/soil relation ship. 4 On the track with tillage soil, results showed that the forward speed was the lowest among the three soil conditions due to the front and rear tires slippage which is higher than vegetal covered and firm soil tracks. Fuel consumption results showed higher values on tilled tracks when comparing with firm and vegetal covered tracks. Data of available power at the drawbar were statistically equal on tilled and vegetal-covered soil tracks... (Complete abstract click electronic access below) / Orientador: Kléber Pereira Lanças / Coorientador: Antonio Gabriel Filho / Banca: Ulisses Rocha Antuniassi / Banca: Alberto Kazushi Nagaoka / Mestre

Made available in DSpace on 2014-06-11T19:24:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-28Bitstream added on 2014-06-13T19:11:21Z : No. of bitstreams: 1 jesuino_pr_me_botfca.pdf: 476686 bytes, checksum: b6b3eacddcfc45310d76d3ad06ae705f (MD5) / Esse trabalho foi realizado com o objetivo de comparar o desempenho de um trator equipado com pneus diagonais novos e pneus diagonais desgastados, em três condições de superfície: pista com solo mobilizado, pista com cobertura vegetal e pista com solo firme. Foi utilizado o delineamento experimental em faixas, sendo que em cada faixa (pista) foram dispostos os tratamentos em blocos ao acaso, com um arranjo fatorial de 2x4, definidos pelos dois conjuntos de pneus diagonais (novos e desgastados) e quatro condições de deslocamento, distinguidas pela mudança de marcha do trator, totalizando oito tratamentos, com três repetições cada, perfazendo 72 unidades experimentais. Foram coletados os dados para o cálculo da velocidade de deslocamento, patinagem das rodas traseiras e dianteiras do trator e consumo horário de combustível. Também foram coletados os dados de força de tração, sendo calculada a potência disponível na barra de tração em função da velocidade de deslocamento. Foi utilizado como carro dinamométrico a Unidade Móvel de Ensaio na Barra de Tração - UMEB, pertencente ao Núcleo de Ensaios de Máquinas e Pneus Agroflorestais - NEMPA, do Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas - FCA da UNESP, Campus de Botucatu - SP. Os resultados mostraram que tanto as condições dos pneus quanto as condições do solo interferiram na capacidade do trator em desenvolver força de tração, sendo o 2 pior desempenho obtido na pista com solo mobilizado. O melhor desempenho do trator foi na pista com solo firme; porém, na pista com cobertura vegetal ocorreram as melhores condições de força de tração do trator em relação ao solo mobilizado, mostrando que a presença da cobertura vegetal entre o rodado e o solo interferiu diretamente na relação rodado/solo. Na pista com solo mobilizado os resultados mostraram que a velocidade foi a menor... / The objective of this work was to compare the performance of a tractor equipped with used and new bias-ply tires, operating in three surface conditions: tillage soil, vegetal covered soil and firm soil. The experimental design were tracks and, in each track, treatments were disposed in blocks to the chance in a 2x4 factorial arrangement, defined by the two groups of tires (used and new bias-ply) and four speed conditions, distinguished by tractor s gear change, totaling eight treatments, with three repetitions each, completing 72 experimental units. There were collected data to calculate: speed, front and rear tires slippage and fuel consumption. There were also collected data of traction strength to calculate available power at traction bar versus speed. The dynamometric car used was the Mobile Drawbar Test Unit - UMEB, owned by the Facility of Agricultural and Forestry Tires and Machines Assays (NEMPA) of Rural Engineering Department in the Agronomics Science College - FCA, UNESP, Botucatu campus. Results showed that both, tires and soil conditions, changed tractor capacity on developing traction strength. The worst performance was observed on the tillage soil. On the track with soil covered with vegetal residues, occurred better tractor traction strength conditions than on track with tillage soil, showing the presence of vegetal cover between tire and soil interfered directly on the tires/soil relation ship. 4 On the track with tillage soil, results showed that the forward speed was the lowest among the three soil conditions due to the front and rear tires slippage which is higher than vegetal covered and firm soil tracks. Fuel consumption results showed higher values on tilled tracks when comparing with firm and vegetal covered tracks. Data of available power at the drawbar were statistically equal on tilled and vegetal-covered soil tracks... (Complete abstract click electronic access below)

Thesis (M. Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2021 / Small-scale farmers are the drivers of many countries in Africa and play an important role in livelihood creation among the poor in rural areas (DAFF, 2012). The efficient use of scarce resources in promoting agricultural production has encouraged a considerable amount of research in determining efficiency differentials of small-scale farmers (Chiona, 2011); especially those engaged in maize as a staple commodity in many parts of the world. The study examined the effect of access to tractor service on technical efficiency of small-scale maize farmers following the implementation of the Masibuyele Emasimini programme in the Mpumalanga province. The objectives of the study were to: (i) Compare and identify the socio-economic characteristics of small-scale maize farmers in the three selected districts of the study, (ii) analyse the socio-economic factors influencing small-scale maize farmers’ access to tractor service, and to (iii) measure technical efficiency of farmers who have access to tractor service. The data collection was carried out in three districts of the Mpumalanga province, that is, Ehlanzeni, Nkangala and Gert Sibande. Farmers producing maize were purposively selected for the study because maize is the most staple food produced in the province, especially on a small-scale level. To effectively cover the study area, a simple random technique was used for sampling with a semi-structured questionnaire administered to 101 farmers. The three districts are heterogeneous in technical aspects, and were therefore treated separately in terms of data collection, analysis and report of findings. The data were further analysed using descriptive statistics, the logistic regression and Cobb-Douglas production function model to address objective one, two and three mentioned above, respectively. The results of the logistic regression model indicated that out of the 9 (Nine) socio-economic variables included in the analysis, 6 (Six) of them (Farmer’s association, irrigation, farmer’s level of education, gender, ownership of land and household size) were found to be significant and influencing access to v tractor service by small-scale maize farmers. Technical efficiency levels revealed that farmers with access to tractor service were more technically efficient than those without access in all districts of the Mpumalanga province. For example, the average technical efficiency for small-scale farmers with access to tractor service in the Ehlanzeni district was 0.68; about 41% higher than those without access with an average technical efficiency of about 0.27. The Cobb-Douglas results on the other hand, revealed that farmers in the Mpumalanga province are experiencing technical inefficiency in maize production due to decreasing returns to scale. Access to tractor service was also negatively insignificant towards maize production in both the Ehlanzeni and Nkangala district, and was found to have a positive but insignificant effect in Gert Sibande. Policy implications are that to improve the efficiency of tractor service (rendered by the Masibuyele Emasimini programme) towards maize production; government should focus on significant factors influencing the access of the following by small-scale maize farmers and the factors are machinery, irrigation, gender, and ownership of land, farmer’s level of education, farmer’s association, and household and land size per district. / National Research Foundation (NRF)

Call number: LD2668 .T4 1986 R43 / Master of Science / Biological and Agricultural Engineering

Made available in DSpace on 2014-06-11T19:31:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-03-30Bitstream added on 2014-06-13T18:42:34Z : No. of bitstreams: 1 rossi_ma_dr_botfca.pdf: 1978510 bytes, checksum: 3ccb830eb4adf611b4323655ceeb3092 (MD5) / The introduction of new technologies in plantation fields, such as the use of tractors machines for agricultural activities, brought some problems to operators. The purpose of this research is to analyze the tractors and harvesters agricultural operator s working place in order to avoid security and health problems that the use of new technologies may bring to them. For this research, eight tractors and two harvesters agricultural with average power of 66kw were used. All ten agricultural machines belong to the Universidade Estadual Paulista, city of Botucatu, State of São Paulo, Brazil. The existing literature regarding to the diversity in ergonomics and agricultural tractors and harvesters was analyzed and discussed. Together with the ergonometry technical parameters and agricultural tractors and harvesters machines themselves, other researches were required such as those related to anthropometry, interface systems - information and action, human tiredness, noise, comfort - seats and conformities, biomechanics - control and handling, working environment and technology. At first, a demand analysis methodology was used by applying individual questionnaires to the operators of the agricultural machines in order to collect information, such as muscular and mental tiredness. The result of the demand analysis revealed the problem, and therefore, the need to apply an Ergonomic Analysis of the Work (AET) by using four approaches of this methodology. The approaches were: anthropometry, biomechanics, comfort and noise. In anthropometry, the method was applied by comparing the anthropometric measures to the measures of eight of the agricultural tractors machine 4 operators and two harvesters. In biomechanics the measures of control and handling location regarding two tractors and one harvester agricultural were taken, in that case, it was necessary a scientific method based on the existing... (Complete abstract click electronic access below)

Orientador: João Eduardo Guarnetti dos Santos / Banca: Luiz Gonzaga Campos Porto / Banca: Marizilda dos Santos Menezes / Banca: Antonio Gabriel Filho / Banca: Jair Rosas da Silva / Abstract: The introduction of new technologies in plantation fields, such as the use of tractors machines for agricultural activities, brought some problems to operators. The purpose of this research is to analyze the tractors and harvesters agricultural operator’s working place in order to avoid security and health problems that the use of new technologies may bring to them. For this research, eight tractors and two harvesters agricultural with average power of 66kw were used. All ten agricultural machines belong to the Universidade Estadual Paulista, city of Botucatu, State of São Paulo, Brazil. The existing literature regarding to the diversity in ergonomics and agricultural tractors and harvesters was analyzed and discussed. Together with the ergonometry technical parameters and agricultural tractors and harvesters machines themselves, other researches were required such as those related to anthropometry, interface systems - information and action, human tiredness, noise, comfort - seats and conformities, biomechanics - control and handling, working environment and technology. At first, a demand analysis methodology was used by applying individual questionnaires to the operators of the agricultural machines in order to collect information, such as muscular and mental tiredness. The result of the demand analysis revealed the problem, and therefore, the need to apply an Ergonomic Analysis of the Work (AET) by using four approaches of this methodology. The approaches were: anthropometry, biomechanics, comfort and noise. In anthropometry, the method was applied by comparing the anthropometric measures to the measures of eight of the agricultural tractors machine 4 operators and two harvesters. In biomechanics the measures of control and handling location regarding two tractors and one harvester agricultural were taken, in that case, it was necessary a scientific method based on the existing... (Complete abstract click electronic access below) / Doutor

CNPq / As transformações que as indústrias vêm passando são uma representação de um novo período industrial também conhecido como Indústria 4.0. Neste cenário de inovações, os conceitos relacionados à Manufatura Inteligente fazem com que haja uma busca constante pela captura do conhecimento visando aprimorar a eficiência de produtos e processos. Portanto, alterações no projeto de produtos voltadas para a melhoria da confiabilidade devem ser realizadas nas etapas inicias do Processo de Desenvolvimento de Produtos (PDP) para que os impactos técnicos e econômicos sejam reduzidos. É neste contexto que a abordagem Design for Reliability (DfR) surge como o conjunto de atividades que tem como intuito garantir a confiabilidade de um produto durante todas as etapas do seu ciclo de vida. Analisando as pesquisas mais recentes acerca do assunto e informações fornecidas por uma empresa de maquinários agrícolas, observou-se que em nenhum caso houve uma implementação do DfR nas etapas iniciais do PDP para determinação do plano de testes a partir do perfil de uso de algum produto. Dessa forma, estabeleceu-se o objetivo desta pesquisa de acordo com a elaboração de um método, baseado em um modelo ontológico, que permita a determinação do plano de testes eficaz e adequado às características de uso dos produtos. Para que esse método fosse desenvolvido, a abordagem metodológica Design Science Research (DSR) foi adotada. Dessa maneira, seis etapas tiveram de ser percorridas: 1) identificação do problema e motivação; 2) definição dos objetivos e solução; 3) projeto e desenvolvimento; 4) demonstração; 5) avaliação e 6) comunicação dos resultados. A solução reproduzida atende as necessidades dos usuários por ser um método eficiente e de simples execução, bem como aprimora a confiabilidade dos produtos ao longo do ciclo de vida. Este trabalho pode ser aplicado no processo de criação de diversos produtos trazendo vantagens significativas para empresas. / The transformations that the industries are currently facing represent a new industrial period also known as Industry 4.0. In this scenario of innovations, concepts related to Smart Manufacturing make a constant search for knowledge capture to improve the efficiency of products and processes. Therefore, changes in product design aiming the improvement of reliability should be undertaken from the early stages of the New Product Development process (NPD) to reduce technical and economical impacts. It is in this context that the Design for Reliability (DfR) approach emerges as the set of activities that aims to ensure the reliability of a product during all stages of its life cycle. Analyzing the most recent research on the subject and some information provided by an agricultural machinery company, it was not observed any case of implementation of DfR in the initial stages of the NPD to determine the test plan taking into consideration the product usage profile. Thence, the main goal of this research was established according to the elaboration of a method, based on an ontological model, which allows the determination of the more appropriate test plan considering the usage characteristics of products. In order to develop this method, the methodological approach Design Science Research (DSR) was adopted. In this way, six stages had to be covered: 1) problem identification and motivation; 2) definition of objectives and solution; 3) design and development; 4) demonstration; 5) evaluation and 6) communication of results. The final solution meets users' needs by being an efficient and easy-to-run method, as well as by enhancing products’ reliability throughout their lifecycle. This work can be applied in the process of creating several products bringing significant advantages to companies.