The mission objective of the Phobos Sample Return is to collect and return 100 g of Phobos’ surface material to Earth inside a tight enclosure composed of a Vault, a Sample Container and sealing elements. One important aspect of the project was the development of a closing mechanism capable of ensuring a pushing force high enough compared to the available force of the robotic arm (40 N). The need for a higher pushing force derived from the design tests which were carried out to experimentally determine the necessary force to overcome the resistance of the sealing element when the vault is closed. Two types of sealing elements, custom made for this project, along with two SC with different geometrical shapes in the sealing area were tested. For better accuracy, the tests considered the imposed operational temperature domain for the vault, ECSS standards and the test rig set-up being performed at environmental temperature (+20 °C), −20 °C, −60 °C and +70 °C. The results of the tests highlighted that the negative temperature has a significant influence over the closing force, as this force is increasing once the operational temperature is decreasing. Based on the work performed, the most suitable type of sealing element was identified, in particular the piston geometry which allows a smaller force to close the vault.
Commonly, millions of employees are exposed to occupational health issues, including noise exposure during working hours. Noise is most encountered in industry sector but can also be found in a wide range of other workplaces (airports, concert halls, offices, etc). In this article, we review the noise levels inside a machine shop, for a single working place, with the scope to assess the occupational safety, discuss research approach in identifying the noise issues, control and reduce it. Generally, noise exposure is an expensive issue, with many particularities to be solved and the exact cost is difficult to calculate. This study offers the perspective of what can be done for similar working places and how to perform this in order to protect the employees to be noise exposed above the legal noise limits and relevant conclusions are offered in this direction.
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