Sharif Digital Repository

Passenger Vehicle Type Choice (PVTC) has an undeniable impact on crash severity and costs. To estimate that, one must carefully consider subjective factors as well as objective ones. Ignoring the role of subjective variables can cause bias in the estimation of the effective variables' coefficients. The present paper investigates the impact of safety attitude, transportation attitude, and lifestyle on PVTC in a bi-level structure. To do so, we used the data from 633 face-to-face interviews conducted in Iran. The passenger vehicles investigated in this study are divided into five categories according to their weight and safety performance: mini, compact, medium, large, and sport utility... 

Airlift Systems (ALS) are widely used in various industrial applications. As the main part of the flow through ALS's upriser pipe, is formed by gas-liquid flow, the analysis of such systems will be accompanied by problems of two-phase flow modelling. Several effective variables are involved in ALS; thereupon comprehensive method is needed to consider these parameters. Exergy analysis can be considered as a simple solution for the realisation of the preferred domain of ALS's operation. Here, this method has been proposed to examine the performance of ALS. Based on thermodynamic principles, an analytical model has been implemented in each phase and the respective experimental data have been... 

In this study a new linear variable reluctance (LVR) resolver is proposed for linear motion control systems. The proposed resolver works based on the sinusoidal variation of air-gap length. Both signal and excitation windings are wound on primary teeth while the secondary has no winding. Two different configurations are examined for the sensor: long, stationary primary with short, moving secondary and long, stationary secondary with short, moving primary. The effect of secondary's number/shape of saliencies and primary's winding configuration on the accuracy of detected position is discussed. 2-D and 3-D time stepping finite element method (FEM) are used for analysis. By comparing the... 

Prediction of accident frequency based on traffic and roadway characteristics has been a very significant tool in the field of traffic management. The accident frequencies on 185 roadway segments of the city of Mashhad, Iran, for the year 2007, were used to develop accident prediction models. Negative Binomial Regression, Zero Inated Negative Binomial Regression, Support Vector Machine and Back-Propagation Neural Network models were used to fit the accident data. Both fitting and predicting abilities of the models were evaluated through computing error values. Results show that the NBR model is the most effective model for predicting the number of accidents because of its low prediction and...