Evaluation of tractive performance of four agricultural tractors in laterally inclined terrain

The present work aimed to evaluate the tractive performance of four agricultural tractors with auxiliary front traction in function of six lateral inclinations in a lateral track of trials, which belongs to the Agronomic Sciences Faculty from the São Paulo State University, Campus of Botucatu. The lateral inclinations were 0; 5; 10; 15; 20 and 25 degrees. In all of these situations, the tractors operated with predetermined load of an imposed traction to the pulled tractor of 40 kN in the inclination of 0 degrees. Hence a delineation in random blocks was used, considering six inclinations and four tractors, and with three repetitions for each treatment. The analyzed variables were slippage, tractive force, hourly fuel consumption, and speed. It was concluded that the pneumatic tire configurations influenced in the tractive performance of the tractors, as they increased the lateral inclinations of the terrain.

A multicriteria model to assess tractors used in family agriculture

In recent years, public policy has been offering subsidized credit for machine purchase to family farmers. However, there is no methodological procedure to select a suitable tractor for these farmers' situation. In this way, we aimed to develop a selection model for smallholder farmers from Pelotas city region in the state of Rio Grande do Sul. Building a multicriteria model to aid decisions is divided into three main stages: structuring stage (identifying stakeholders, decisional context and model creation), evaluation stage (stakeholder preference quantification) and recommendation stage (choice selection). The Multicriteria method is able to identify and value the criteria used in tractor selection by regional family farmers. Six main evaluation areas were identified: operational cost (weight 0.20), purchase cost (weight 0.22), maintainability (weight 0.10), tractor capacity (weight 0.26), ergonomics (weight 0.14) and safety (weight 0.08). The best-rated tractor model (14.7 kW rated power) also was the one purchased by 53.3% of local families.

Evaluation of tractive performance of four agricultural tractors in laterally inclined terrain

O presente trabalho teve como objetivo avaliar o desempenho operacional de quatro tratores agrícolas com tração dianteira auxiliar, em função de seis inclinações laterais, em uma pista lateral de ensaios, pertencente à Faculdade de Ciências Agronômicas da Universidade Estadual Paulista, Câmpus de Botucatu. As inclinações laterais foram 0; 5; 10; 15; 20 e 25 graus. em todas estas situações, os tratores operaram com carga predeterminada de tração imposta ao trator tracionado de 40 kN na inclinação de 0 grau. Portanto, foi utilizado um delineamento em blocos casualizados (DBC), sendo seis inclinações e quatro tratores, e com três repetições para cada tratamento. As variáveis analisadas foram patinhagem, força de tração, consumo horário de combustível e velocidade de deslocamento. Concluiu-se que a configuração dos rodados pneumáticos influenciaram no desempenho operacional dos tratores, conforme aumentaram as inclinações laterais do terreno.

Operational safety: Development of electronic system for dynamic balance evaluation of farm tractors

The present study aimed at the development and evaluation of a low cost electronic device in order to provide safety for farm tractor users. The major accident occurrence in agricultural surroundings is from farm tractor side bending. Therefore, this sensor was designed to detect and alert about it. The results were satisfying. © 2013 Taylor & Francis Group.

Complex higher spins, Weyl invariance and tractors

In this thesis work I analyze higher spin field theories from a first quantized perspective, finding in particular new equations describing complex higher spin fields on Kaehler manifolds. They are studied by means of worldline path integrals and canonical quantization, in the framework of supersymmetric spinning particle theories, in order to investigate their quantum properties both in flat and curved backgrounds. For instance, by quantizing a spinning particle with one complex extended supersymmetry, I describe quantum massless (p,0)-forms and find a worldline representation for their effective action on a Kaehler background, as well as exact duality relations. Interesting results are found also in the definition of the functional integral for the so called O(N) spinning particles, that will allow to study real higher spins on curved spaces. In the second part, I study Weyl invariant field theories by using a particular mathematical framework known as tractor calculus, that enable to maintain at each step manifest Weyl covariance.