Sharif Digital Repository

In this thesis we are going to improve an ultrasonic flowmeter accuracy by considering the influence of different parameters like temperature, pressure, etc. Firstl of all different cases of flow condition in which ultrasonic flowmeter may work are specified, then velocity and temperature profile of pipe flow are determined using Fluent software. In thr next step ultrasonic pulses transmitted are simulated by the use of code written in Matlab to find wave travel time in the flow. Evetually an accurate relation of calibration for flowmeter is determined by the use of travel time and all other flow properties to evaluate the accuracy of flowmeter in diffent cases. Relation extracted can be... 

Exchange-rate has always been one of the critical macroeconomic factors influencing Iran’s economy. As a representative of the whole economy, the stock market is also affected by exchange rate fluctuations. However, the direction and the delay of this impact is not similar for all firms. This study aims to find the time and direction of the reactions to dollar fluctuations in the two most recent jumps, during 1390 and 1397, for all firms listed on Tehran Securities Exchange. It also seeks to determine why among stocks with a positive reaction, some react sooner, and some react later, based on their specific characteristics. Using a distributed lag model, we found that about one-half of the...