The parametric analysis of the centrifugal insurance mechanism in MEMS safety and arming device
In this paper, a MEMS S&A device has been proposed. The size of the device is φ 12×0.3mm. The role of the centrifugal insurance mechanism is to ensure the safety in handling transportation and storage, and reliable firing with the launch overload. Through establishing the three-dimensional model of the centrifugal insurance mechanism, establishing the force and the parameters of the centrifugal insurance mechanism, deriving the mathematical model according to the rigid dynamic mechanics theory and establishing the finite element model by using ANSYS/LS-DYNA, appropriate centrifugal insurance mechanism is designed to meet two items, one item is deformation of elastic beam can reliably release slider when the speed is more than 30000r/min and the centrifugal insurance mechanism can restrict the slider again when the speed is reduced; the other item is the centrifugal insurance mechanism can effectively restrict the slider to ensure the safety of the device when primary insurance accident arming in handling transportation.
The Analysis of the Characteristics and Trend of the Foreign Fuze Technology and the Necessary of the Rapid Developing of Our Fuze Technology
The characteristics and tides of recently foreign fuze technologies are analysed in this paper.Rapid developing our fuze technologies is necessary.The key of realizing our fuze technologies from tradition to intelligence is developing information fuze technologies.
Using Fuzzy-Delphi technique to determine the concession period in BOT projects
BOT projects are affected by several risks and uncertainties. One of the most important issues in this type of contract is to determine the length of concession period considering these uncertainties. The previous studies have developed several models to determine the concession period. However, the uncertainties are not taking into account in most of the previous works. Moreover, none of the previous researches has the capability to aggregate the opinions of different experts being involved in a project regarding the values of the uncertain input parameters. In this research, a Fuzzy-Delphi technique is implemented to determine the length of concession period considering uncertainties. Using the proposed Fuzzy-Delphi technique, the values of different uncertain factors affecting a BOT project is determined considering opinions of a group of experts. The NPV value is calculated considering the resulted aggregated values of uncertain input parameters. Finally, the concession period is determined using fuzzy approach. A case study is conducted to evaluate the performance of the proposed methodology. It is shown that the concession period is determined more effectively using the proposed approach.