In this paper two system safety models are built based on some practical situations. The system state can be distinguished into three states: working, fail-safe and fail-dangerous.The probabilities that the system are in working state, fail-safe state and fail-dangerous state, respectively, are derived. Also the mean times for the system working, fail-safe and fail-dangerous, are given. Finally...

Rock burst is the most attractive and hot research area in geomechanics, mining, and civil engineering due to the increasing depth of mines and construction of deep underground structures. It has also been a severe problem in ground control measures in the last few decades. Many studies have been done by different researchers in order to minimize the hazards of rock burst and to provide a safe ...

When organizing the educational process in higher education institutions, safe conditions must be created that meet all general current requirements of labor protection. The most common physical factor adverse effects on students classrooms are man-made electromagnetic fields around each technical means and different configurations relative location equipment. Based fundamental relations dipole...

evaluating the application of safe suction criteria by nurses working in intensive care unit in urmia     amirzade n [1] *, baghaei r [2] , feizi a [3] , khorsandi f [4]     received: 19 jan , 2013 accepted: 12 mar , 2013   abstract   background & aims : suction is considered as an essential process to keep the trache tube open for patients under mecanical ventilation.howevereit has detrimental...