this paper studies an m/g/1 repairable queueing system with multiple vacations and n-policy, in which the service station is subject to occasional random breakdowns. when the service station breaks down, it is repaired by a repair facility. moreover, the repair facility may fail during the repair period of the service station. the failed repair facility resumes repair after completion of its re...

conclusions in general, time indices including length of patient stay in the ed and space capacity, emphasizing the need to address these shortcomings. materials and methods this analytical cross-sectional study was conducted via the faculty members of the ed and residents of shahid beheshti university of medical sciences in tehran, iran. data were collected using a predefined questionnaire. de...

the colorado beetle, leptinotarsa decemlineata (say), is the major defoliating and exotic insect pest of potato plants and has caused serious problems in the east azerbaijan and ardabil regions of iran since emerging in the absence of natural native enemies. in the development of a suitable control strategy based on integrated pest management, it is important to recognize control methods that d...

Improving the constructability of a facility design is a key concern for owners, designers, and builders of facilities. Prior research has shown that a product model based on a 3D CAD model of a facility can support constructability reasoning to assist a project team in identifying constructability issues. This paper shows how a 4D facility model (3D plus time) improves constructability reasoni...

Regulatory entities require that for any radiation facility the surrounding areas must be restricted unless the dose equivalent is less than 0.02 mSv in any one hour. Two Monte Carlo radiation transport simulation codes, MCNP5 and Mercurad, were used to design a facility to shield a 3.48 x 10(5) MBq 137Cs irradiator that meets these requirements. Simulations showed that the dose equivalent rate...