O desgaste de órgãos ativos de máquinas e implementos agrícolas de preparo do solo tem sido alvo de vários estudos pela comunidade científica que relaciona tal ocorrência com o desempenho operacional, vida útil, material e técnica de fabricação. Este desgaste ocorre independentemente do tipo de manejo do solo, porém, determinadas práticas podem potencializá-lo a ponto de comprometer as condições desejadas de implantação de uma cultura em virtude da modificação geométrica da sua extremidade de corte. Órgão ativo comprometido aumenta a força de tração e por conseqüência acarreta aumento no consumo de combustível. Diversas variáveis podem influenciar o desgaste entre as quais se destacam a velocidade de trabalho, teor de água do solo, material de fabricação e tratamento térmico. Diante disso, o objetivo deste trabalho foi de descrever os principais tipos de ensaios de materiais, bem como construir uma avaliação crítica, com base na literatura encontrada, sobre desgaste de órgãos ativos analisando as metodologias e os resultados. Considera-se tal análise de grande relevância para agricultores, para indústria e para pesquisadores de modo geral. / The wear of tillage tools by agricultural implements has been aim of some studies of scientific community that such occurrence with operational performance relates useful, material and technique manufacture. This wear occurs independently of the type handling of the soil, however, determined practical can to increase it point to compromise the desired conditions of implantation culture in virtue of the geometric modification of the cutting edge. Compromised tillage tool increases the draft force and for consequence it causes increase the fuel consumption. Some variable can influence the wear, among which if they detach the work speed, moisture, manufacture material and heat treatment. Ahead of this, the aim of this work was to describe the main types of tests about subject, as well to make a critical evaluation of joined literature. Such analysis of great relevance for farmers, industry and researchers in general way is considered.

Com o avanço da agricultura de precisão, em que a variabilidade da produtividade entre os diversos pontos de uma determinada área é levada em consideração, é necessário aprimorar, cada vez mais, o sistema de coleta de dados, para que os resultados possam ser confiáveis. Dentre outros, faz-se necessário conhecer o desempenho dos sensores localizados nas colhedoras, para que se saiba o nível de acurácia dos dados de campo para a geração dos mapas de produtividade. O objetivo do presente trabalho foi caracterizar o desempenho, sob condições controladas, de um equipamento comercial, especialmente o sensor de fluxo de volume e suas interações com os sensores de inclinação, de velocidade de deslocamento da máquina e de grau de umidade dos grãos, destinados à mensuração da produtividade de culturas de grãos em geral. Foi montada uma bancada de ensaio constituída de um tanque alimentador com comporta de abertura variável, que escoa grãos a um condutor helicoidal, que são transportados para um elevador de taliscas de uma colhedora comercial. Os grãos transportados pelo elevador passam através dossensores de fluxo de volume e grau de umidade e, em seguida, são descarregados num tanque superior suspenso por uma célula de carga com capacidade de 2.000kg (desprezando a variação da gravidade com relação ao nível do mar) para que os dados de massa sejam comparados com os registrados pelo sensor de fluxo de volume. O monitor de produtividade foi ensaiado na bancada para simulações de fluxos constantes e variados em três diferentes posições transversais do elevador. Os resultados mostraram que a bancada de ensaio mostrou-se eficiente para os tipos de ensaios propostos. Sua estrutura é resistente e a variação da angulação do elevador é de fácil manejo. A geometria da construção do tanque de alimentação mostrou-se eficiente para fornecer vazões uniformes com o tempo, obtendo-se taxas de fluxo constantes dentro dos limites de 2,0 a 8,0kg.s-1. O sensor de velocidade apresentou erro médio relativo de 0,31% e o de grau de umidade, erro médio em módulo de 5,01% para as condições estudadas. Quanto mais afastado do fluxo médio de calibração, pior é a estimativa do fluxo pelo monitor de produtividade. O erro médio geral dos ensaios com taxas de fluxo constantes foi de -5,31%, com desvio padrão de 4,14. O monitor propiciou, em 70% dos ensaios, erros pontuais menores que 6% para ensaios com fluxo constante. Suas leituras superestimaram valores menores do que o ponto da taxa de fluxo média de calibração e subestimaram valores para taxas de fluxo maiores que este ponto. As leituras do monitor responderam imediatamente as variações impostas ao fluxo processado pelo elevador de grãos. O clinômetro ou o algoritmo que considera a inclinação é eficiente para compensar as inclinações transversais da máquina, mesmo em condições de taxas de fluxo variadas. O erro médio geral dos ensaios com taxas de fluxo variadas, calculado a partir do erro médio em módulo de cada ensaio foi, 4,84%. O erro médio global encontrado do monitor de produtividade para as leituras com taxas de fluxo constantes e variadas, foi 5,12%. / With the progress of the precision agriculture where spatial yield variability is taken into account, it is necessary to improve data collection so the results can be more reliable. It is necessary to understand how yield sensor used on combines works in order to know the accuracy of the field data for generation of the yield maps. This work aims to characterize the performance, under controlled conditions, of a commercial equipment, its yield sensor and interactions with the hillside sensor, forward speed sensor and grain moisture sensor. A test bench with a tank feeder was built with a variable opening floodgate, which drains grains to the foot of the paddle elevator of a commercial combine. The grain flow transported by the elevator pass through the yield and moisture sensor and is unloaded in a superior tank hold by a load cell with capacity of 2.000kg (desconsidering the variation of the gravity) so that the mass data is compared with that registered by the monitor. The monitor was tested on simulations of constant and variable flow rates in three different transverse positions of the elevator. The results showed that the test bench was shown efficient for the types of proposed tests. Its structure is resistant and the variation of the angle of the elevator is of easy handling. The geometry of the feeding tank was shown efficient to supply uniform flow rates, between 2,0 and 8,0kg.s-1. The speed sensor showed relative mean error of 0,31% and the moisture sensor presented a module mean error of 5,01%. Flow estimation got worst increasing or decreasing the flow rate apart from calibration region. Main mean error of the test with constant flow rates was of -5,31%, with standard deviation of 4,14. On 70% of the test monitor, readings resulted in erros less than 6,00% with constant flow. Its readings overestimated flow values under the mean flow rate of calibration and underestimated flow above it. The readings of the yield monitor responded to the variations imposed to the flow through by the elevator immediately. The hillside sensor and the algorithm that considers the inclination are efficient for compensating the transverse inclinations of the machine, even in conditions of varied flow rates. The general mean error test with varied flow rates, was 4,84%. The global mean error shown by the yield monitor for the readings with varied and constant flow rates was 5,12%.

Orientador: Carlos Eduardo Angeli Furlani / Banca: Rouverson Pereira da Silva / Banca: Jorge Wilson Cortez / Banca: Afonso Lopes / Banca: Wilson José Oliveira de Souza / Resumo: O sistema plantio direto como prática conservacionista associado a técnicas como a integração lavoura-pecuária, tem como foco principal otimizar o uso das áreas agrícolas. Nessa condição, a opção do consórcio de milho com forrageiras constitui uma alternativa para suprir o aporte anual de palha e tornar o sistema sustentável. O presente trabalho teve como objetivo, em dois anos agrícolas, avaliar, no primeiro, três forrageiras (Brachiaria brizantha, B. decumbens e B. ruzizienses) em consórcio com duas populações de plantas de milho e, no segundo, verificar o efeito da palhada dos tratamentos do ano anterior na semeadura do milho em duas velocidades do conjunto trator-semeadora. O experimento foi conduzido na área da Fazenda de Ensino, Pesquisa e Produção da UNESP/Jaboticabal, SP, o solo da área experimental é classificado como LATOSSOLO VERMELHO Eutroférrico típico, A moderado, textura argilosa. Foi utilizado o delineamento em blocos ao acaso, no esquema fatorial (2x3), com quatro repetições. No ano agrícola 2008/2009, os tratamentos foram constituídos por duas populações de plantas de milho (55 e 75 mil plantas ha-1) consorciado com três forrageiras semeadas na entrelinha 30 dias após a semeadura do milho, totalizando 24 parcelas. Para o ano agrícola 2009/2010, a semeadura do milho foi realizada nas mesmas parcelas do ano anterior, com palhada proporcionada pelo consórcio das três forrageiras com milho e duas velocidades de deslocamento do conjunto trator-semeadora (6,0 e 7,7 km h-1). A população de 75 mil plantas ha-1 em consórcio com B. brizantha e B. ruzizienses, promoveu maiores valores de produtividade de grãos e as forrageiras promoveram maior quantidade de massa seca residual, com maior porcentagem de cobertura do solo para brizantha (2008/2009). Para o segundo ano agrícola, a variação da... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: No tillage system as a conservation practice associated with techniques such as crop-livestock integration focuses primarily to optimize the use of agricultural areas. Given this condition, the option of corn intercropped with forage constitutes an alternative to supply the annual intake of straw and make the system sustainable. The study aimed, in two growing seasons, to evaluate in the first year three forages (Brachiaria brizantha, B. decumbens and B. ruzizienses) intercropped with two populations of corn plants, and in the second year to determine the effect of the straw treatment from previous year in two speeds of the tractor-seed drill. The experiment was conducted in the experimental area of the Laboratory of Agricultural Machinery and Mechanization of UNESP / Jaboticabal County, São Paulo State, Brazil. The soil is classified as typiceutroferric Red Latossol, clayey. Randomized blocks design was used for the experimental layout forming a factorial arrangement of 2x3 with 4 replications. In the crop year of 2008/2009, treatments consisted of two corn plants populations (55 and 75 000 plants ha-1) sown intercropped with three forages 30 days after sowing of corn, totaling 24 plots. For crop year of 2009/2010 corn sowing was performed on the same plots as in the previous year but with two forward speeds of the tractor-seeder (6.0 and 7.7 km h-1), over the straw provided by the consortium of the corn and three forages. The population of 75,000 plants ha-1 in association with B. brizantha and B. ruziziensis promoted the highest values for grain productivity, and the forages promoted greater amount of residual dry matter, being B brizantha (2008/2009) with the highest percentage of soil cover. For the second crop season, speed variation of seeding affected the operational performance of the... (Complete abstract click electronic access below) / Doutor

The thesis presented consists of two essays that analyze input substitution and decision making in crop and livestock production systems. The first essay consists of a whole-farm analysis that sought to optimize feed mixes and enterprise combinations for an organic dairy operation in the Southeastern United States. This was accomplished through mathematical programming where whole-farm net returns were maximized, and total feed costs were minimized simultaneously for four milk production level cases. Additionally, the sensitivity of the system and break-even milk price were explored. Results suggest substitutability in ration components where an increase in supplemental feeds is justified by additional milk output and sales. The second essay utilizes econometric methods and hedonic modeling to explore factors that drive the price of row crop planters on the used machinery market. Factors relating to make, age, condition, planter specifications, sale type, spatial aspects, seasonality, and year of the sale were analyzed. Results suggest non-linear relationships for row number and age relative to price and interactions between variables make and age that imply varying depreciation depending on the manufacturer. An additional break-even analysis relating to pasture yields and planter purchase price was conducted to explore these primary concepts in further detail.

Growing energy demand in the world force people to investigate alternative energy sources. Unlike coal or other fossil fuels, renewable energy sources are promising for the future. Especially, seed oils are effectively used as energy sources such as fuel for diesel engines. The scope of this study is to develop an oil extraction machine specific to canola seed. In this study, seed oil extraction methods have been investigated and various alternatives for the extraction machine have been considered. For continuous operation, oil extraction with a screw press is evaluated as the most appropriate solution. Four different prototypes have been designed and manufactured. According to the results of testing of prototypes, they have been modified and gradually improved to increase oil extraction efficiency. The working principle of the selected screw press based on the rotation of a tapered screw shaft mounted inside a grooved vessel. The screw shaft is a single square-threaded power screw having an increasing root diameter from inlet to exit while the outside diameter of the screw shaft is 66 mm. Seeds are taken into the system at the point where the depth of the screw thread is maximum. Then they are pushed forward by the threads on the rotating screw shaft and pass through inside the vessel. So, the fed seeds are compressed as they move to the other side of the vessel. Recovered oil escapes from high pressure zone and drains back. The oil is drained out from the oil drainage holes that are machined on high pressure zone of the vessel. Besides, the cake is extruded at the end of the vessel and the screw shaft. The cake thickness is adjustable by the axial movement of the screw shaft. By adjusting the cake thickness, different pressures can be obtained. During the experiments, it is observed that four main features affect the oil recovery rate. These are the geometry of the grooves inside the vessel, the taper angle of the screw shaft, the operating temperature and the rotational speed. With the final prototype, an oil recovery efficiency of 62.5% has been achieved at 40 rpm with 15 kg/h seed capacity. Since the oil content of the seed is taken as 40%, oil recovery rate of the developed oil extraction machine is 3.75 kg/h. This efficiency is determined for a 0.8 mm cake thickness at 1.1 kW motor ower.

This thesis is aimed at identifying the noise sources of a wheeled tractor to reduce the noise levels below the legislative limits by controlling noise sources through proper methodologies. The study focuses firstly on identifying the noise sources of a wheeled tractor by using proper noise source identification techniques. These techniques can be summarized as sound intensity measurements, sound power level determination studies and spectral analysis of the noise data acquired in the tests. Simple sound intensity mapping techniques are used and the intensity contour maps are generated to identify the noise sources. Most important and effective noise sources are identified and the critical noise sources are focused to apply appropriate noise control strategies not only at the prototype production stages but also at the early design stages. Consequently, upon consideration of both structure-borne and flow-induced noise, the pass-by noise level and the operator&rsquo / s ear noise levels of the tractor are reduced by nearly 3 dB (A) through application of proper noise control strategies.

Mechanical properties of polymers are reviewed and the phenomenon of the abrasive wear is analyzed in the literary part. The researches of other authors on the abrasive wear and their results are surveyed. Laboratory equipment for carrying out the abrasive wear researches is introduced. Optimal mount of laboratory simulation for modeling polymeric material wear in the abrasive environment is chosen. The testing materials‘ properties are characterized. The results of researches on polymeric materials, used in enginery, on the wear in the abrasive environment are presented. The carried out research showed that wear results of the same materials under different testing conditions (“polymer-abrasive”, “polymer-steel disc” ASTM G176-03) the dependence of wear on hardness end on the coefficient of friction differs. That is influenced by the choice of polymeric materials. The scope of the work is 62 pages: 57 pictures, 1 table, 7 appendixes are included, 25 sources of literature were referred to in this work.

There is evidence that soil compaction, through the use of mechanised equipment, causes detrimental effects to soil quality and reduces long-term productivity of soils. For economic reasons, farmers need to purchase larger, heavier machinery in order to cultivate larger areas under crops, resulting in larger forces on the soil. The severity of soil compaction is governed by various soil and vehicle properties and normally causes an increase in the soil's bulk density and a decrease in the air filled porosity. These changes in soil properties have negative effects on crop production and environmental sustainability. The aim of this study was to investigate and develop a model based decision support system for soil compaction management and research. Soil compaction occurs during the transfer of stresses from the tyre interface into the soil. Numerically, it has been modelled using both mechanistic and empirical models, which attempt to simulate the stress propagation and also sometimes the consequent damage to the soil. The SOCOMO soil compaction model is described and this model computes the stress at a point in the soil for any given horizontal and vertical stress distribution at the soil / tyre interface. It has been successfully used in the Netherlands and in Sweden to map the impact on the soil. The SOCOMO model was tested and verified at a forestry site in Richmond, KwaZulu- Natal. Relationships to determine bulk density were also tested and verified. The SOCOMO model performs satisfactory (RMSE = 47.9 kPa), although it tends to overestimate the pressures within the soil. This could be as a result of the high organic carbon content in the particular soil. Models predicting bulk density also performed satisfactory (RMSE = 69.9 kg.m" ), but resultant densities in the soil are generally underestimated. Future research is needed to find better relationships to estimate changes in dry bulk density and to test the model on a wider range of soils. If the model performs satisfactory it could provide a useful tool to determine the impact of soil compaction on crop yield. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2006.

Sugarcane hauliers in South Africa have high variations in vehicle payloads, which influence both transport economics and the legitimacy of their operations. Increasing economic pressure due to declining sugar prices and ever increasing fuel prices has invoked interest to improve vehicle utilisation and reduce costs, while complying with the local traffic legislation. On-board weighing technologies, such as on-board load cells, could assist operators to control their payloads more accurately and hence reduce the frequency of both over and under loaded consignments. In this study, an investigation is conducted to evaluate the feasibility of on-board weighing systems in the South African sugarcane transport industry. An overview of on-board weighing systems is presented. The overview gives insight into the technical composition of an on-board weighing system as well as presenting various benefits and drawbacks that are associated with an on-board weighing system. Earlier studies conducted on the use of on-board weighing systems are scrutinised and evaluated and it is concluded from these that vehicle utilisation could be improved, while concurrently reducing the overloading of vehicles. Field research was conducted to evaluate the accuracy and consistency of on-board weighing systems currently being utilised in the sugarcane transport industry as well as to determine the critical factors that influence the effectiveness of the system while assessing if overloading of vehicles was reduced when on-board weighing systems were employed. It was concluded that the systems evaluated were reasonably accurate with mean error being 0.4 tons. The consistency of the systems was good with 75% of all measurement being within 0.5 tons of each other. The critical factors determining the effectiveness of the on-board weighing systems were established as being management of the system as well as cane variety and quality. Overloading was reduced by 9% in one field evaluation and 5% in another. Further reduction can be realised through tighter management of the on-board weighing systems. An economic evaluation of an on-board weighing system was performed using the capital budget method. This method was used to determine the pay off period required to realise the investment into an on-board weighing system for scenarios where the payload is increased by 2, 3 and 4 tons and transport lead distance is 20, 40, 60, 80, and 100 km. The shortest pay off period occurred when the lead distance was 60 km and the time was 1, 2 and 3 years for payload increases of 2, 3 and 4 tons respectively. For lead distances of 40, 60 and 80 km the investment is worthwhile and considerable returns in investment can be realised, however, for the other lead distances the pay off period could be deemed to be too long. From the observation made during the field evaluation together with the literature studied, guidelines for the use of on-board weighing systems under various transport scenarios were formulated and are presented in chapter six. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2009.

Swine industry in Brazil, due to its growth in recent years, has generated a great quantity of waste, especially in the liquid form, which can be used, by means of agricultural equipment employment, in soil treatment and correction. The majority of small and medium businesses in the Brazilian industrial field of agricultural machinery adopts the trial and error system, not making use of any procedure that systematically assist the process of product design, which can cause problems in the conception generation and/or failure in the operating machinery. The present thesis questions whether the realization of field tests is sufficient to reduce fault problems in the final conception of agricultural machines. Thus, we proposed as main objective a comparative study of failure analysis of a liquid swine waste distributing and incorporating equipment (DLS), realized under two different approaches, by means of prototypes I and II. The first one involves an analysis of equipment testing and experimenting reports (dynamic approach) concerning prototypes I, and II, realized during the usage phase. The second one involves the employment of a systematics of equipment failure analysis - prototype II under the perspective of product design, by applying the FMEA - Failure Modes and Effects Analysis (static approach). In both approaches, the ways results were obtained were specifically analyzed, suggesting improving actions according to certain failure modes. The dynamic approach has aimed the verification of operational activities of the equipment in field, in real work conditions, allowing the identification of faults and problems by means of observation. a partial analysis of equipment failure with a reduced number of considerations if compared to Case II, presenting results that contemplate non-conformities, difficulties, and problems in some subsystems and equipment components during the equipment utilization. The static approach, departing from the equipment functional and structural analysis, allowed evidence in the systems, subsystems, and components on the modes, causes and effects of possible faults, totaling 108 possible modes of failure, whose 11 were considered as potentials. The use of FMEA technique justifies the importance of incorporating a way for preventing faults during every phase and stage concerning the product designing. Therefore, this study verifies that both approaches allow the establishment of a interaction of results, recommendations and suggestions which permit eliminating or minimizing failure in the final conception of agricultural machinery. However, the FMEA technique application within a systematization of fault analysis since the beginning of the equipment design allows for the suggestion of improvement actions in the prototype before it is submitted to tests and experiments. / A suinocultura no Brasil, devido ao seu crescimento nos últimos anos, tem gerado uma grande quantidade de dejetos, especialmente sob a forma líquida que pode ser aproveitada, por meio do emprego de equipamentos agrícolas, no tratamento e correção do solo. A maioria das empresas de pequeno e médio porte do setor industrial brasileiro de máquinas agrícolas adota o sistema de tentativa e erro , não fazendo uso de algum procedimento que auxilie sistematicamente no processo de desenvolvimento do produto, o que pode causar problemas na geração de concepção e/ou de falhas nas máquinas em operação. Esta tese em seu trabalho de pesquisa questiona se as realizações de testes em campo são suficientes ou não para atenuar os problemas de falhas na concepção final das máquinas agrícolas. Assim, foi proposto como objetivo geral um estudo comparativo da análise de falhas de um equipamento distribuidor e incorporador de dejetos líquidos suínos (DLS) realizado sob duas abordagens distintas, a partir dos protótipos I e II. A primeira, abrange uma análise de relatórios de testes e experimentos do equipamento (abordagem dinâmica) referente aos protótipos I e II, realizados durante a fase de uso. A segunda, compreende o emprego de uma sistemática de análise de falhas do equipamento - protótipo II sob a ótica de projeto do produto, pela aplicação da técnica FMEA - Análise dos Modos de Falhas e seus Efeitos (abordagem estática). Em ambas as abordagens foi analisada, de maneira específica, a forma de obtenção dos resultados, sendo sugeridas ações de melhoria em determinados modos de falhas. A abordagem dinâmica objetivou a verificação de atividades operacionais do equipamento em campo, em condições reais de trabalho permitindo identificar falhas e problemas por meio de observação. Já a abordagem estática, partindo da análise funcional e estrutural do equipamento, permitiu evidenciar, no sistema, subsistemas e componentes os modos, causas e efeitos das possíveis falhas, totalizando 108 possíveis modos de falhas, sendo 11 considerados como potenciais. A utilização da técnica FMEA justifica a importância de incorporar um modo de prevenção de falhas que abrange todas as fases e etapas referente a concepção do produto. Assim, constata-se que ambas as abordagens possibilitam estabelecer uma interação de resultados, recomendações e sugestões que permitem eliminar ou atenuar falhas na concepção final de máquinas agrícolas. Contudo, a aplicação da técnica FMEA dentro de uma sistematização de análise de falhas a partir do início do projeto do equipamento possibilita que sejam sugeridas ações de melhorias ao protótipo, antes de ser submetido a testes e experimentos.