Optimal work-rest schedules under prolonged vibration.
This research was conducted for the purpose of studying the performance and recovery characteristics of men when subjected to low-level, whole-body vertical sinusoidal vibration for durations of one to two hours. Several male subjects performed a vertical compensatory tracking task using a CKT display according to three work-rest schedules under both normal and vibratory environments. The vibratory environment was that of vertical sinusoidal vibration with a frequency of.5 cps and an amplitude- of 0-08 inches resulting in an acceleration intensity of approximately 0.20 g. The working period was divided into equal intervals during which performance was continuously monitored. Decrement of performance was measured using absolute error score. Results and conclusions are presented regarding performance decrement and recovery under varying work-rest schedules. Optimum work-rest schedules and implications of control tasks under a vibratory environment are discussed.
Performance and recovery under prolonged vibration
Abstract : The research was conducted for the purpose of studying the performance and recovery characteristics of men when subjected to relatively long periods of whole-body, vertical vibration. The effect of environment, and of a work/rest schedule, upon performance and recovery were investigated. Analysis of the performance in terms of duration of exposure to vibration was also undertaken. (Author)
Effects of different loads on the surface of silver metal oxide contacts for general-purpose relays
Silver metal oxides have become very popular as contact materials in electromechanical switching devices due to their high resistance to erosion and contact welding. Initially, these materials were developed for contactors and circuit breakers. Investigations on silver metal oxide contacts for general-purpose relays were conducted in order to gain an insight into the effects and failure mechanism of such contacts under specific loads, such as resistive and inrush current loads. It will be shown that contact failures may be influenced by very thin silver layers on the surface of silver metal oxide materials and the behavior of these layers at thermal stress. The silver layers are a result of the mechanical treatment in the production of rivets and the following riveting process. The results support the development of new silver metal oxide materials for general-purpose relay applications.