In Spain, there are more than 250,000 tractors built before 1980, when it became mandatory for all new tractors to be equipped with a rollover protective structure (ROPS). A similar situation is found in the European Union, but the situation is worse in the U.S. and in developing countries. Directive 2003/37/EEC establishes that tractors over 800 kg weight can be homologated by using the OECD s...

in iran, onion plants are currently broadcast over the majority of onion fields and weeding and harvesting are done manually by seasonal workers. at harvest time, 40 worker-days are required to onion dig just one hectare. this cost could be saved if the operation could be carried out by machine. rear-mounted diggers can only be implemented if 40 cm spacing between rows is allowed for each tract...

The aim of this paper and its prequel is to introduce and classify the irreducible holonomy algebras of the projective Tractor connection. This is achieved through the construction of a ‘projective cone’, a Ricci-flat manifold one dimension higher whose affine holonomy is equal to the Tractor holonomy of the underlying manifold. This paper uses the result to enable the construction of manifolds...

This paper aims to classify the holonomy of the conformal Tractor connection, and relate these holonomies to the geometry of the underlying manifold. The conformally Einstein case is dealt with through the construction of metric cones, whose Riemannian holonomy is the same as the Tractor holonomy of the underlying manifold. Direct calculations in the Ricci-flat case and an important decompositi...

In a tractor hydraulic/transmission oil contamination is a serious problem as it works in such environment, these contamination may be in different forms dust particles, water, oxidation & corrosion products ,wear metal particles. Metal wear particles plays a significant role in failure of hydraulic system such as jamming of control valve, worn out of sealing element etc. Removal of these metal...

The rollover accidents in the tractor semi-trailer are often fatal and many factors could cause the tractor semitrailer rollover. In this paper, a rollover prevention control method was proposed based on real-time calculation of rollover index. The vehicle Center of Gravity CG height from the ground is an important parameter in the rollover index and it is estimated through lateral acceleration...

Bates et al. extended the "tax-adjusted reSelf-employment taxes, "effective" marginal placement model" by incorporating the interactax rates, and discounting schemes which allow ton between taxes and inflation in their study. for alternative purchase and disposal dates of They found that inflation increased the magnimachinery are incorporated into the traditional tude of costs and generally ext...

Parabolic geometries may be considered as curved analogues of the homogeneous spaces G/P where G is a semisimple Lie group and P ⊂ G a parabolic subgroup. Conformal geometries and CR geometries are examples of such structures. We present a uniform description of a calculus, called tractor calculus, based on natural bundles with canonical linear connections for all parabolic geometries. It is sh...

Since the mid 1990’s, advances in global positioning systems (GPS), microprocessors, actuators, controllers, plant/soil sensors and geographical information systems (GIS) have spawned the development of new, site-specific, variablerate techniques for chemical applications. At the same time, agricultural production has embraced other new technologies that increase the productivity of mechanized ...