Narrow-Track Agricultural Tractors: A Survey on the Load of the Hand-Operated Foldable Rollbar.
To protect the driver in case of a tractor overturn, narrow-track tractors (used in vineyards and orchards) can be equipped with a rollover protective structure (ROPS) consisting of a two-pillar front-mounted foldable rollbar. The transition from the horizontal (rest) to the vertical (protection) position of this ROPS is performed manually by the driver. In addition to the time spent performing this task many times each day, a moderate physical load is required, given that these rollbars often have a mass of some tens of kilograms. In practice, neglect and poor attention to safety lead to the foldable rollbar remaining continuously in the rest position rather than being moved to the vertical (protection) position. Several rollover accidents have been fatal for the driver because the tractor, although equipped with a two-pillar front-mounted ROPS, had the rollbar in the horizontal position at the time of the event, thus assuring no protection to the driver. This issue is quite serious. To remove at least one of the problems for the proper management of this type of ROPS, the OECD has recently updated its Code 6 by introducing an optional test addressing the manual handling of front-mounted rollbars, providing a maximum load of 100 N. Several tests were conducted on new rollbars to ascertain the accuracy of this limit. The 100 N value was generally exceeded, which is cause for criticism. Indeed, a more appropriate reference for manual handling in this case would be the higher loads (up to 250 N) already provided by other standards for non-continuous tasks.
ROPS designs to protect operators during agricultural tractor rollovers.
Although it is well known that properly used Rollover Protective Structures (ROPS) can virtually prevent agricultural tractor rollover fatalities, the U.S. still has hundreds of these fatalities per year. An estimated 1.6 million tractors are not equipped with ROPS. Many of these tractors do not have ROPS commercially available although they were originally designed to support a ROPS. Some tractors have foldable ROPS that are not used properly. Other ROPS, although meet appropriate performance standards, are not effective at eliminating continuous rolls. To meet this need, a Computer-based ROPS Design Program (CRDP) was developed to quickly generate ROPS designs based on agricultural tractor weights and dimensions. The ROPS designed with the CRDP for the Allis Chalmers 5040 tractor successfully passed the SAE J2194 static longitudinal, transverse, and vertical tests. A simple foldable ROPS lift assist was designed and tested to ease in the raising and lowering of ROPS; decreasing the raising torque from 90 Nm to less than 50 Nm, while also lowering the resisting torque to lower the ROPS. A model to determine the critical ROPS height CRH based on off-road vehicle dimensions and center of gravity (CG) height was developed and evaluated.
Study on the gaseous emissions from a landfill
Abstract Emissions from landfills contain a variety of compounds, organic and inorganic, which can create problems with human health. Here we examine the pollutants methane, hydrogen sulphite, mercaptans, sulphur dioxide, nitrogen dioxide and certain volatile organic compounds (VOCs) that are expected to be found in landfill emissions, in order to assess the environmental impact on the surrounding area. Results indicate that the concentrations in the landfill itself are quite high and in most cases above the ambient air quality limits, while for the surrounding area they are low. The problem is created by H 2 S and the mercaptans which, although in low content, have a distinct odour and cause problems to the neighbouring dwellings.