Background: Estimation of the size of hidden and hard-to-reach sub-populations, such as drug-abusers, is a very important but difficult task. Network scale up (NSU) is one of the indirect size estimation techniques, which relies on the frequency of people belonging to a sub-population of interest among the social network of a random sample of the general population. In this study, we estimated ...

the static pull-in instability of beam-type micro-electromechanical systems is theoretically investigated. two engineering cases including cantilever and double cantilever micro-beam are considered. considering the mid-plane stretching as the source of the nonlinearity in the beam behavior, a nonlinear size-dependent euler-bernoulli beam model is used based on a modified couple stress theory, c...

in the present study, through the application of self-determination theory the impact of work climate and social network size on the volunteers motivation were investigated. research type of this study is applied and research method type is descriptive. in this study active volunteers of tehran red crescent society were selected as statistical population .concerning the population of studied ce...