José Fernando Schlosser

Caracterização dos acidentes com tratores agrícolas

Despite its importance, few researches have been carried out characterizing work accidents involving agricultural tractors. The objective of this work was to characterize the accidents with agricultural tractors, to determine more efficient ways to prevent them. A questionnaire was applied to an ample of agricultural tractor operators from the Central Region of Rio Grande do Sul State. Results showed that 39% of the agricultural tractor operators analyzed had already suffered some kind of accident. The most frequent type of serious accidents was tractor overturning which occurred in 51.71% of the cases. Slips were the most important slight accident. The most important causes of accidents were lack of knowledge about safety procedures on tractor operation (32.77%), lack of attention (32.22%) to the task carried out and inadequate equipment (22.22%). There were great differences between the causes of serious and slight accidents. Operators without adequate training, no observation of some important safety procedures and very long working day were reported in this research, collaborating to increase the occurrence of accidents. Finally, it is necessary to incorporate confort and security devices, as well as training the agricultural tractor operators, to prevent future accidents.

Características ergonômicas dos tratores agrícolas utilizados na região central do Rio Grande do Sul

It is possible to reduce the probability of work accidents, diseases occurrence and increase the work efficiency using agricultural tractors with good ergonomic conditions. The objective of this research was to verify the presence of ergonomic items in used agricultural tractors and also to evaluate the influence of tractor age in these characteristics. 175 agricultural tractors belonging to 3 regions of Rio Grande do Sul State (Santa Maria, Restinga Seca and Cachoeira do Sul, Brazil), present in 114 farms randomly sampled, were evaluated. The results showed that only 3% of sampled specimens were equipped with a cab, and most part of the tractors did not have protection against the heat produced by tractor transmission and engine. With regard to ergonomics of commands, more than 70% of the tractors had gear levers positioned in its longitudinal central line, and only 8% were equipped with adjustable steering wheel. In the same way, more than 20% of sampled specimens did not have upholstered seat. Besides, the presence of the evaluated items were smaller for older tractors.

Desempenho de motor de injeção direta sob misturas de biodiesel metílico de soja

The aim of this study was to evaluate the use of soybeans methyl biodiesel blends and diesel in an ignition compression engine with fuel direct injection. The tests were performed in a dynamometer bench, using the blends B10, B20 and B100 compared to the commercial diesel (B5). The engine performance was analyzed by tractor power take off (PTO) for each fuel. The best results obtained for the power and the specific fuel consumption, respectively, were: B5 (44.62kW; 234.87g kW-1 h-1); B10 (44.73kW; 233.78g kW-1 h-1); B20 (44.40kW; 236.20g kW-1 h-1) and B100 (43.40kW; 263.63g kW-1 h-1). It was concluded that the best results happened on the use of B10 fuel (more power in only 0.2% than fuel B5 and lower specific consumption in only 0.5% than B5). The B100 fuel showed significant differences compared to the other fuels (power lower 2.8% than B5 and more specific consumption in 10.9% than B5).

Influência do avanço cinemático das rodas dianteiras sobre a eficiência em tração de tratores com quatro rodas motrizes não isodiamétricas

The objective of this experiment was to study the effect of cinematic relationship between trator axles on traction efficiency of four-wheel tractor drive system. Results indicated that a higher traction efficiency was observed when cinematic relationship was close to one (using the same peripheral wheel speed). Considering a hard soil surface the trator absorbed vibrations due to interference between axles. However, on a soft soil surface the trator traction was smooth with a higher front wheel slippage index.

Sistema computacional de gerenciamento para acompanhamento de desempenho de máquinas agrícolas instrumentadas com sensores

The G-SADA is a computer system that assists the management of the farm manager and the operator of agricultural machinery in decision making, reporting values of non- standard operations. The system is characterized by allowing a) monitoring the performance of the machine while it is operating in the field, with features in real time, b) mobility of the user because it can be accessed from any computer, including mobile devices such as smartphones, c) and features with access to the database static. One of the results of this research is the modeling data and functions of an application that uses data stored dynamically with the machine in operation in the field, provided by sensors deployed in agricultural machinery, showing real time information.

Análise comparativa do peso específico dos tratores agrícolas fabricados no Brasil e seus efeitos sobre a seleção e uso

The aptitude and performance of the agricultural tractors on field conditions have been influenced by the tractor weight. This parameter has varied mainly according to the manufacturers, generating a demand of comparative information. The objective of this research was to analyze the weight of Brazilian agricultural tractors, aiding in the selection and in its appropriate use. The present research included 103 models of commercial tractors of the brands Massey Ferguson, Agrale, New Holland, John Deere, Ursus and Valtra. Tractor weight and weight/power relationship, separately in different brands, traction type and power groups, were analyzed. The data were analyzed through the t test (Student). Significant differences were observed for the brands and power groups when the weight/power relationship was considered. The parameter weight has differed also for the traction type. Besides, the weight/power relationship without ballast weight has decreased with the increase of power. Therefore, Brazilian agricultural wheeled tractors are heterogeneous regarding weight and weight/power, what influences their economic performance. These parameters must be considered during the use and choice of a tractor.

Acidentes de trabalho envolvendo conjuntos tratorizados em propriedades rurais do Rio Grande do Sul, Brasil

The objective of this work was to determine generic and specific causes of work accidents involving tractor-implement systems, to help taking more effective prevetion measures. The research was carried out in twenty-one municipal districts belonging to three regions of Rio Grande do Sul State, Brazil: Santa Maria, Restinga Seca e Cachoeira do Sul. 114 farms were randomly sampled in these regions, in which 141 operators were evaluated. The accidents analyzed were both te ones that occurred with the owner or employees of the same farm and the ones that occured with operators not belonging that farm - but whose cases were known by the interwiees - 82% of the work accidents involving tractor-implement systems were caused by unsafe actions and 18% by unsafe conditions. The most important specific causes of accidents occurred in the sampled farms were tractor operation on bent grounds, giving to somebody a lift and excessive consumption of alcohol. Therefore, it is possible to conclude that measures taken to prevent work accidents with tractor-implement systems must priorize the especific causes detected in this research.

Aplicação de fertilizantes a taxa variável em agricultura de precisão variando a velocidade de deslocamento

The main purpose of this work was to evaluate the performance of a set formed by an agricultural tractor equipped for precision farming and a broadcaster spreader not adapted for applications of fertilizers at variable rates. The variations of the rates of fertilizer application were controlled by varying the travel speed. The width, uniformity of traverse and longitudinal distribution and the variation of the applied rate of NPK fertilizer were determined. The study was accomplished in a commercial farming of soybeans in the city of Santa Rosa, RS. For better reliability of the tests, a soil condition and farming relief that would represent a real situation of use of the mechanized set were looked for. The results showed that, in the study situation and with the used fertilizer, it is possible to use the set for widths between 20.5 and 22.5 m in the continuous application circuit and back-and-forth, with variation coefficient below 15%. In the analysis of the longitudinal profile of distribution, the values of variation coefficients between 8.78 and 12.48% were obtained. The mechanized set allows composing several application rates varying the travel speed in the system of precision farming.

Desempenho de misturas pré-aquecidas de óleo de soja cru e diesel como combustível para motores agrícolas

O oleo de soja e um dos oleos vegetais que tem potencial de uso como combustivel para motores diesel, pois e renovavel, seguro e de facil utilizacao. Em temperatura ambiente, o oleo cru apresenta uma viscosidade cerca de dez vezes maior que a do oleo diesel. Para reduzir a viscosidade do oleo de soja a niveis aceitaveis, e necessaria uma temperatura de aquecimento em torno de aproximadamente 60°C ou mistura-lo com oleo diesel. O objetivo deste estudo foi avaliar o desempenho do oleo de soja cru e suas misturas com oleo diesel, pre-aquecidas antes da bomba injetora entre 57°C e 68°C, como combustivel para motores diesel. O desempenho das misturas combustiveis foi avaliado num motor monocilindrico de injecao indireta e comparado com o obtido pelo oleo diesel. Os ensaios de curta duracao foram conduzidos entre 1.800 e 2.800rpm, sob condicao de plena carga em dinamometro hidraulico. Ensaios realizados a 68°C apresentaram sempre os melhores valores para torque, potencia e consumo especifico de combustivel do que a 57°C. Uma mistura composta por 70% de oleo de soja e 30% de oleo diesel, aquecida a 68°C, apresentou os melhores resultados.

Eficiência operacional na colheita mecanizada em lavouras de arroz irrigado

The objective of this research was to evaluate the time efficiency and the field efficiency of the harvesting operation in rice fields, located in the region of Depressao Central of Rio Grande do Sul, Brazil. In the summer of 2008/2009, 19 operations were evaluated, being fifteen fields of them with land level and four without land level. The operation data were collected through the use of stopwatch, a clip board to record observations and with a signal receiver of GPS (Global Positioning System). There was no significant difference in the 5% level of probability of error between operations with land level and operations without land level. The field efficiency was calculated through the methodology used by GRISSO et al. (2002), and have been found the average of 65.2%, the time efficiency was determinate based on the concept of Hunt (2001), which have determined an average of 75.7%. Unload making combining with operation increase the field efficiency.