nonlinear hunting speeds of railway vehicles running on a tangent track are analytically obtained using hopf bifurcation theory in this paper. the railway vehicle model consists of nonlinear primary yaw dampers, nonlinear flange contact stiffness as well as the clearance between the wheel flange and rail tread. linear and nonlinear critical speeds are obtained using bogoliubov method. a compreh...

generally icu patients are in critical status and need long stay in icu. pulmonary rehabilitation program (prp) is considered as an important tool to improve outcome and shorten the length of stay in icu. the aim of this study was to investigate whether prp can affect outcome and duration of hospitalization in icu patients. this study was performed in medical icu of labafi nejad hospital, tehra...

background posttraumatic stress disorder (ptsd) is a severe anxiety disorder occurred due to past adverse experiences. several researches have demonstrated that ptsd is quite common among patients discharged from critical care unit. conclusions prevalence of ptsd is high among patients discharged from icus and some medical individual factors such as elderly, unemployed, being single, using mech...

I n the United States and most other countries, primary air quality standards are designed to protect human health and are based on concentrations of pollutants in the air. However, from the perspective of ecosystem health, a more appropriate metric for the impacts of nitrogen (N) and sulfur (S) pollutants is the total atmospheric deposition (or “load,” in kg·ha·y) of N and S, because ecosystem...

Critical path method is a network based method planned for development and organization of complex project in real world application. In this paper, a new methodology has been made to find the critical path in a directed acyclic graph, whose activity time uncertain. The vague parameters in the network are represented by intuitionistic triangular fuzzy numbers, instead of crisp numbers. A new pr...

the above equation, we can see that we will get the best performance if we choose a blocking factor that is a multiple of 3. In general, the theorem implies that there are only blocking factors to consider; this characterizes the critical path for all unfoldings greater than. In this paper, we have developed a formulation for the problem of finding optimal blocking factors for blocked, non-over...

In a fuzzy project network, the higher risk path is called possible critical path. Secondary critical path is one of the possible critical path in fuzzy project network and it plays an important role in the project scheduling, risk analysis and time-cost trade-off problems in fuzzy environment. In this paper, triangular fuzzy numbers are used to express the operation times for all activities in...

We describe a new algebraic technique for enumerating self-avoiding walks on the rectangular lattice. The computational complexity of enumerating walks of N steps is of order 3 N/4 times a polynomial in N , and so the approach is greatly superior to direct counting techniques. We have enumerated walks of up to 39 steps. As a consequence, we are able to accurately estimate the critical point, cr...

the chechen republic (commonly referred to as chechnya) is a part of vast territory of russian federation that has been a source of contention since collapse of the soviet :union:. identity elements and tattered cultural bonds have strained ties between two nations of chechnya and russia. various aspects of crisis in chechnya have been addressed by many theoretical approaches of international r...