• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 3
  • 1
  • 1
  • Tagged with
  • 11
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

The effect of the standard density gin press on marketing Arizona cotton

Johnson, Dehard B. (Dehard Bruce), 1923- January 1949 (has links)
No description available.
2

Modeling and validation of the baling process in the compression chamber of a large square baler

Afzalinia, Sadegh 30 May 2005
<p>The pressure-density relationship and the pressure distribution inside the compression chamber of a newly designed New Holland BB960 large square baler were studied for the baling of alfalfa, whole green barley, barley straw, and wheat straw. An analytical model was developed for the pressure distribution inside the compression chamber of the large square baler in the x-, y-, and z-directions by assuming isotropic linear elastic properties for forage materials. In order to validate this model, a tri-axial sensor was designed and used to measure the forces inside the compression chamber when whole green barley, barley straw, and wheat straw were baled. The experimental results proved that the developed analytical model for each of the tested forage materials had a good correlation with the experimental data with a reasonable coefficient of determination (0.95) and standard error (20.0 kPa). Test data were also used to develop an empirical model for the pressure distribution inside the compression chamber of the baler for each of the tested forage materials using least square method in regression analysis. These empirical models were simple equations which were only functions of the distance from the full extension point of the plunger along the compression chamber length.</p><p>Analytical and empirical models were also developed for the pressure-density relationship of the baler for baling alfalfa and barley straw. Results showed that bale density initially decreased with distance from the plunger, and then remained almost constant up to the end of the compression chamber. The developed empirical model for both alfalfa and barley straw was a combination of a quadratic and an exponential equation. In order to validate the developed models, field tests were performed by baling alfalfa and barley straw of different moisture contents, flake sizes, and load settings. The forces on the plunger arms were recorded by a data acquisition system. The actual bale bulk density was calculated by measuring the bale dimensions and weight. Results showed that both load setting and flake size had a significant effect on the plunger force. The plunger force increased with increased load setting and flake size. Comparing analytical and empirical models for bale density as a function of the pressure on the plunger showed that the trend of variation of density with pressure in both models was similar, but the rate of change was different. The variation rate of density with pressure in the analytical model was higher than that of the empirical model. The analytical model underestimated the bale density at low plunger pressures but showed more accurate prediction at higher pressures, while the empirical model accurately predicted the bale density at both low and high pressures. Some crop properties such as coefficient of friction and modulus of elasticity were determined for the development of the pressure distribution model. Results showed that static coefficient of friction of alfalfa on a polished steel surface was a quadratic function of material moisture content, while the relationship between the coefficient of friction of barley straw on a polished steel surface and material moisture content was best expressed by a linear equation. Results of this study also proved that modulus of elasticity of alfalfa and barley straw was constant for the density range encountered in the large square baler.</p>
3

Modeling and validation of the baling process in the compression chamber of a large square baler

Afzalinia, Sadegh 30 May 2005 (has links)
<p>The pressure-density relationship and the pressure distribution inside the compression chamber of a newly designed New Holland BB960 large square baler were studied for the baling of alfalfa, whole green barley, barley straw, and wheat straw. An analytical model was developed for the pressure distribution inside the compression chamber of the large square baler in the x-, y-, and z-directions by assuming isotropic linear elastic properties for forage materials. In order to validate this model, a tri-axial sensor was designed and used to measure the forces inside the compression chamber when whole green barley, barley straw, and wheat straw were baled. The experimental results proved that the developed analytical model for each of the tested forage materials had a good correlation with the experimental data with a reasonable coefficient of determination (0.95) and standard error (20.0 kPa). Test data were also used to develop an empirical model for the pressure distribution inside the compression chamber of the baler for each of the tested forage materials using least square method in regression analysis. These empirical models were simple equations which were only functions of the distance from the full extension point of the plunger along the compression chamber length.</p><p>Analytical and empirical models were also developed for the pressure-density relationship of the baler for baling alfalfa and barley straw. Results showed that bale density initially decreased with distance from the plunger, and then remained almost constant up to the end of the compression chamber. The developed empirical model for both alfalfa and barley straw was a combination of a quadratic and an exponential equation. In order to validate the developed models, field tests were performed by baling alfalfa and barley straw of different moisture contents, flake sizes, and load settings. The forces on the plunger arms were recorded by a data acquisition system. The actual bale bulk density was calculated by measuring the bale dimensions and weight. Results showed that both load setting and flake size had a significant effect on the plunger force. The plunger force increased with increased load setting and flake size. Comparing analytical and empirical models for bale density as a function of the pressure on the plunger showed that the trend of variation of density with pressure in both models was similar, but the rate of change was different. The variation rate of density with pressure in the analytical model was higher than that of the empirical model. The analytical model underestimated the bale density at low plunger pressures but showed more accurate prediction at higher pressures, while the empirical model accurately predicted the bale density at both low and high pressures. Some crop properties such as coefficient of friction and modulus of elasticity were determined for the development of the pressure distribution model. Results showed that static coefficient of friction of alfalfa on a polished steel surface was a quadratic function of material moisture content, while the relationship between the coefficient of friction of barley straw on a polished steel surface and material moisture content was best expressed by a linear equation. Results of this study also proved that modulus of elasticity of alfalfa and barley straw was constant for the density range encountered in the large square baler.</p>
4

Mechanical and physical characterization of tire bales

Freilich, Brian Jeremy 05 November 2012 (has links)
Tire bales are a suitable construction material for conditions which require a lightweight material with high permeability and strength. Although several tire bale case histories have been reported in the literature, only limited material properties of the bales are available. Determining the mechanical and physical properties of the tire bales is necessary for the proper design and construction of future tire bale structures. The development and results from a series of large scale laboratory and field test procedures, used to determine the mechanical and physical characteristics of a tire bale structure, are provided in this dissertation. A tire bale structure, as compared to the individual tire bale, is defined as two or more tire bales stacked upon each other resulting in an interface contact between layers of the tire bales. Results from the test programs indicate that the interface between the tire bales controls the strength and compressibility of the bale structure. The strength of the interface was characterized utilizing a large scale direct shear test, which was modified to include the effects of moisture, soil infill and stress orientation on the interface strength. Interface shear stresses were used to define shear strength parameters for the different tire bale interfaces. The compressibility of the tire bale structure was characterized utilizing a large scale vertical compression test. The influence of the individual tire bale geometry on strength and compressibility was determined by conducting the large scale tests on two bale types, the standard block bale and the standard cylinder bale. A tire ridge interface model was developed to represent the physical characteristics of the tire bales that control the strength and deformations along the interface. Tensions within the baling wires were measured during the direct shear and compression tests using strain gauges attached to the baling wires. A tension meter was also developed so that the baling wire tensions could be determined without damaging the tire bale and baling wires. A destructive expansion pressure test was used at the conclusion of the research program to determine the pressures the tire bale exerts on the surrounding structure after wire breakage. / text
5

LABORATORY SCALE CONCEPT VALIDATION AND EVALUATION OF COMPROMISING PLANT NODAL INTEGRITY AS A MEANS TO INCREASE BALE DENSITY

Turner, Aaron P 01 January 2014 (has links)
Transportation costs represent a significant role in the economics of packaged hay and biomass crops. The material’s low bulk density limits transportation efficiency. Density is currently limited by the ability of the baling twine to withstand the expansion forces generated by the baled material shortly after it is ejected from the bale chamber. It was hypothesized that compromising the structure of the plant, particularly the plant nodes could reduce the amount of energy stored in the material as it is compressed and thereby reduce the material’s elastic response to compression. Literature pertinent to the biomass material’s behavior in compression was reviewed. Bulk samples of switchgrass and miscanthus were subject to uniaxial compression, and the required pressure needed to obtain a target density of 256 kg/m3 was compared on a wet and dry density basis. Both switchgrass and miscanthus showed a statistically significant decrease in the required compression pressure, and the interaction between the moisture level and required pressure was also significant. Existing models for the pressure density relationship of compressed bulk material were evaluated for suitability. Individual nodes and internode sections were subject to radial compression and the apparent modulus of elasticity and maximum contact stress were determined.
6

Wrapped forages for horses /

Müller, Cecilia, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.
7

Analise de sensibilidade de seis sistemas de recolhimento do palhiço da cana-de-açucar (Saccharum spp.) / Analysis of six recovery systems for sugarcane trash

Michelazzo, Marcio Beraldo 18 May 2005 (has links)
Orientador: Oscar Antonio Braunbeck / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-05T08:03:35Z (GMT). No. of bitstreams: 1 Michelazzo_MarcioBeraldo_M.pdf: 766633 bytes, checksum: c822032d0a6d200120086d977866cf38 (MD5) Previous issue date: 2005 / Resumo: A biomassa é uma fonte de energia renovável, disponível e alternativa. Quando a colheita é feita sem realização de queimada, a biomassa da cana-de-açúcar, na forma de palhiço, é uma das fontes de energia renovável com enorme potencial no Brasil. Todavia, o aproveitamento desses resíduos em larga escala é dificultado pelo alto custo de seu recolhimento, principalmente no que diz respeito ao recolhimento, adensamento e transporte. Este trabalho analisou tecnicamente algumas características envolvidas no recolhimento do palhiço, tais como massa específica final do palhiço e complexidade das máquinas envolvidas, juntamente com uma análise econômica, por meio de um modelo de cálculo de custo, por meio de simulação de eficiências e capacidades operacionais que compõem cada sistema de recolhimento do palhiço. De acordo com os resultados, o sistema colheita integral apresentou o menor custo de recolhimento do palhiço, tanto para distância pequenas como para grandes distâncias. Seguido pelos sistemas picado a granel, fardo cilíndrico, fardo algodoeiro, peletização e briquetagem / Abstract: Sugarcane is one of the energy sources most readily available in Brazil, mainly due to residues such as trash (tops, dry and green leaves). However, large scale use of these residues still faces high recovery costs related to gathering, baling, transportation, chopping and technology for residue utilization. An analysis was done of the mechanical principles involved in the packing processes. A model was defined to estimate the cost of trash recovery simulating the field capacity, oil consumption, depreciation, repair and maintenance and labor required for the field and transport operations. Six recovery systems were studied both from the technical and economical points of view. The results showed that handling billets and trash together, described as ¿Integral harvest¿, has the lowest cost for trash recovery, both for short and long distances, followed by bulk handling of chopped trash, the round bale, the giant bale and finally the pellet and briquette systems / Mestrado / Maquinas Agricolas / Mestre em Engenharia Agrícola
8

Nová koncepce hydraulického pohonu CPB / New conception of hydraulic drive CPB

Bártek, Petr January 2013 (has links)
The main objective of this master's thesis is to design the new conception of hydraulic drive of the baling press CPB 100 with application of modern tendencies in the field of hydraulic engineering. This thesis contains design and calculations of new hydraulic drive, hydraulic circuit diagram and the list of hydraulic elements that are used. Moreover this thesis includes the design of an electrical control and the design of hydraulic block and manifold.
9

Utilização de um algoritmo de caminho mínimo no processo de recolhimento do palhiço da cana-de-açúcar

Silva, Inara Soldera Romano da [UNESP] 16 December 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-16Bitstream added on 2014-06-13T19:52:21Z : No. of bitstreams: 1 silva_isr_me_botfca.pdf: 1100428 bytes, checksum: 826dc0fb9625c7e450be2699f43ec0bd (MD5) / A atual preocupação com o meio ambiente tem feito com que empresas produtoras de cana-de-açúcar invistam na mudança do sistema de colheita. Essa mudança consiste na redução da queima do canavial na pré-colheita e na utilização do corte mecanizado com cana crua. Porém, a colheita com corte mecanizado torna disponível a biomassa residual e sem as queimadas e com o maior acúmulo do palhiço sobre o solo, criamse condições favoráveis para o aparecimento de parasitas e atraso da brota da cana, comprometendo a próxima safra. Vários autores mostram a viabilidade do uso do palhiço na produção de energia. Pois, além do potencial energético desta biomassa, têm-se como vantagens as questões ambientais, a manutenção de empregos e a substituição dos recursos energéticos de fontes naturais. Mas, as grandes dificuldades ainda encontradas para aproveitamento desse resíduo para geração de energia são o grande número de maquinário envolvido no sistema de coleta deste resíduo e o alto custo que este processo demanda, principalmente o custo com transporte. O presente trabalho tem como objetivo propor aplicações de técnicas matemáticas de otimização para auxiliar o planejamento do recolhimento do palhiço da cana-de-açúcar para aproveitamento na geração de energia, estudando a melhor forma de carregamento dos fardos de palhiço, facilitando o transporte, diminuindo custos e desgastes de maquinários. Para isto, é sugerido o uso de técnicas de agricultura de precisão para mapear o palhiço enfardado, desta forma pode-se definir uma rota para recolher os fardos no campo e transportá-los para o centro de processamento. Para determinação da rota, propõe-se o uso do algoritmo de menor caminho da teoria de grafos, utilizando uma variação do algoritmo de Dijkstra. / The current concern with the environment has made sugar cane growers invest in changing their harvesting system. This change consists of the reduced burning of cane fields before harvesting and the use of mechanized cutting for raw canes. However, mechanized harvesting makes residual biomass available and, without the burning, the major accumulation of crop residue on the ground, creating favorable conditions for the emergence of parasites and delay of new shoots, affecting the next crop. Several authors show the feasibility of using crop residue for energy production. Besides the energy potential of the biomass, there are advantages for the environmental issues, preservation of jobs and the replacement of energy resources from natural sources. But the great difficulties still found in using this residue for power generation are the large number of machinery involved in the collection system of the waste and the high costs of this process, mainly transport costs. This paper aims to propose applications of mathematical optimization techniques to help plan the collection of sugar cane crop residue to be used for power generation, by studying the best way of loading bales of crop residue, making it easy to transport them, therefore reducing costs and wear on machinery. For this, we suggested the use of techniques of Precision Agriculture to map the baled crop residue, which allows you to define a route to pick up the bales in the field and transport them to the processing center. To determine the route, it is proposed to use the shortest path algorithm from graph theory, using a variation of Dijkstra's algorithm.
10

Utilização de um algoritmo de caminho mínimo no processo de recolhimento do palhiço da cana-de-açúcar /

Silva, Inara Soldera Romano da, 1982- January 2009 (has links)
Orientador: Helenice de Oliveira Florentino Silva / Banca: Adriana Cristina Cherri Nicola / Banca: Odivaldo José Seraphim / Resumo: A atual preocupação com o meio ambiente tem feito com que empresas produtoras de cana-de-açúcar invistam na mudança do sistema de colheita. Essa mudança consiste na redução da queima do canavial na pré-colheita e na utilização do corte mecanizado com cana crua. Porém, a colheita com corte mecanizado torna disponível a biomassa residual e sem as queimadas e com o maior acúmulo do palhiço sobre o solo, criamse condições favoráveis para o aparecimento de parasitas e atraso da brota da cana, comprometendo a próxima safra. Vários autores mostram a viabilidade do uso do palhiço na produção de energia. Pois, além do potencial energético desta biomassa, têm-se como vantagens as questões ambientais, a manutenção de empregos e a substituição dos recursos energéticos de fontes naturais. Mas, as grandes dificuldades ainda encontradas para aproveitamento desse resíduo para geração de energia são o grande número de maquinário envolvido no sistema de coleta deste resíduo e o alto custo que este processo demanda, principalmente o custo com transporte. O presente trabalho tem como objetivo propor aplicações de técnicas matemáticas de otimização para auxiliar o planejamento do recolhimento do palhiço da cana-de-açúcar para aproveitamento na geração de energia, estudando a melhor forma de carregamento dos fardos de palhiço, facilitando o transporte, diminuindo custos e desgastes de maquinários. Para isto, é sugerido o uso de técnicas de agricultura de precisão para mapear o palhiço enfardado, desta forma pode-se definir uma rota para recolher os fardos no campo e transportá-los para o centro de processamento. Para determinação da rota, propõe-se o uso do algoritmo de menor caminho da teoria de grafos, utilizando uma variação do algoritmo de Dijkstra. / Abstract: The current concern with the environment has made sugar cane growers invest in changing their harvesting system. This change consists of the reduced burning of cane fields before harvesting and the use of mechanized cutting for raw canes. However, mechanized harvesting makes residual biomass available and, without the burning, the major accumulation of crop residue on the ground, creating favorable conditions for the emergence of parasites and delay of new shoots, affecting the next crop. Several authors show the feasibility of using crop residue for energy production. Besides the energy potential of the biomass, there are advantages for the environmental issues, preservation of jobs and the replacement of energy resources from natural sources. But the great difficulties still found in using this residue for power generation are the large number of machinery involved in the collection system of the waste and the high costs of this process, mainly transport costs. This paper aims to propose applications of mathematical optimization techniques to help plan the collection of sugar cane crop residue to be used for power generation, by studying the best way of loading bales of crop residue, making it easy to transport them, therefore reducing costs and wear on machinery. For this, we suggested the use of techniques of Precision Agriculture to map the baled crop residue, which allows you to define a route to pick up the bales in the field and transport them to the processing center. To determine the route, it is proposed to use the shortest path algorithm from graph theory, using a variation of Dijkstra's algorithm. / Mestre

Page generated in 0.0641 seconds