Sharif Digital Repository

In the past 10 years Iran has been emerging as a major car producer in the world. However, due to delays in economic reforms, Iranian car exports have not increased as much as production. This paper presents a first estimation of the Iranian export potential in the car industry. Based on new theoretical developments of the gravity equation, an empirical bilateral trade model is proposed. It includes sectoral variables (car production, import tariffs), as well as other original variables, such as expectations and hysteresis. We then develop a dataset which includes the 40 major car-exporting countries in the world, 34 importing countries, a 10-year time period as well as four car production... 

New treatment technologies are currently being investigated for the treatment of contaminated drilling waste mud with oil. Supercritical fluid extraction is a promising technology that could be effectively used to extract this contaminated drilling waste mud. In this work, one step extraction efficiency of supercritical carbon dioxide to drilling waste mud of South Pars gas field has been investigated at a range of temperatures (55 to 79.5 °C), and over a pressure range of 160 to 220 bar. Extraction efficiencies were calculated based on cuttings weight loss. Results show that approximately 28.45% of cuttings weight loss in one step extraction at a pressure of 200 bar and temperature of 60 °C... 

Implementation of green management in sports complexes can ensure the continuous arrangement and assessment of activities from an environmental perspective and will end up with the control and prevention of contaminants. Enghelab Sports Complex in Iran was selected for this study due to its size and long-term activities. The establishment of Enghelab Sports Complex is among important national projects whose framework was founded in the late 1950s. Due to the comprehensive plan of the aforesaid sports complex, numerous centers and departments were established in this site in order to materialize its envisioned sports, recreational and cultural objectives. Green management pursues greater... 

In this work we introduce new model for energy-delay product and the performance of 80-nm SOI-CMOS circuits for the range of Vdd=0.1-1.5V and Vth=0-0.8V, are analyzed to find optimal Vdd and Vth BSIMSOI3.3 model (level 57) is used to verify the answers. We show that Energy-Delay Product (EDP) isn't appropriate metric for gate sizing problem. And a new design metric is introduced as a generalization of EDP. This metric is used to determine the transistor sizing for complex circuits based on the specified delay and energy constrains. In this case, unlike the conventional energy delay product metric, delay and energy can be considered with different emphasis. The complete design flowcharts and... 

in this paper detection and the accuracy of measurement of range, velocity and DOA in PCL radar for optimized parameters is considered. It is shown that, in order to measure the bistatic characteristics of a target, we can process the monostatic ambiguity function and extract the bistatic factors by proposed Algorithm. ©2006 IEEE  

According to one survey on energy consumption in Iran, commercial and building sector consume more energy than any other economic sectors. For example, about 38% of total energy that consumed in year 2001 has been used for space heating. Insulation in external walls of buildings has an important role to reduce the environmental effects on indoor space condition. Therefore, always using insulation is an alternative to avoid from the energy loss. In this paper, the effects of the using of a proper insulation on the energy saving in Iranian buildings are studied. For this purpose, an integrative modelling is used for simulation of the energy consumption in buildings. It is shown that energy... 

Caspian Sea is currently a subject of one of the world's most intractable disputes, involving five coastal states of Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan. The conflict over the legal status of this multinational water body emerged after the collapse of the Soviet Union. Since then the parties have been negotiating without reaching an agreement on the ownerships of waters, and the oil and natural gas beneath them. Although different division methods have been suggested so far for sharing the Caspian Sea, the gains of the countries from sea area and valuable resources remain unclear as the proposed methods are either focused on the areal shares or on the oil and gas shares.... 

This paper describes an attempt to shed some light on road safety in Asia Pacific region by characterizing and assessing its road accidents. The relevant national road accident data were extracted from centralized data sources of international agencies. Due to data incompleteness and missing values, 21 Asia Pacific countries, presenting more than half of the world's population, were selected for detailed analysis. The study database consisted of 7 variables, covering years 1980 and 1995. The univariate and multivariate statistical analyses for the selected countries showed interesting results and relations for the selected variables. Accident rates, reflecting road accident risk and... 

Integrated seismic attributes, coherency, acoustic impedance (AI), lambda-rho (λρ) and mu-rho (μρ), were used to delineate and to characterize a complex regional channel deposition system in a carbonate reservoir interval in the upper part of the Sarvak Formation. The study area incorporates three adjacent oil fields in SW Iran (Khuzestan Province) covered by three individual 3D seismic surveys having a total area of about 2800 km 2. We generated a regional horizon-based coherency cube using these three seismic surveys. This revealed a carbonate clastic deposition channelling system over the entire study area. We characterized this channel deposition system in agreement with regional... 

Using an in-house developed software the signal level, the best server cells, and the amount of interference using standard propagation models are determined in a cellular environment. The program is also able to assign the frequency channels automatically to the TRXs taking into account the carrier to interference and the traffic distribution using a genetic algorithm. In this paper, the cost function is based on the total Carrier to Interference ratio (C/I) and the traffic density of the serving area. The software by means of a genetic algorithm approaches a frequency assignment which increases the overall quality of service throughout the cellular network. The package has been used in a... 

Two new designs of wind towers were tested side by side with a conventional wind tower in the city of Yazd, Iran. All the towers were of identical dimensions. The two new designs were one with wetted column, consisting of wetted curtains hung in the tower column, and the other one with wetted surfaces, consisting of wetted evaporative cooling pads mounted at its entrance. The air temperature leaving the wind towers with evaporative cooling provisions were much lower than the air temperature leaving the conventional design, and its relative humidity much higher. The air-flow rate was reduced slightly in these new towers. It was found that the wind tower with wetted column performs better with... 

Owing to the devastating M7.6 earthquake of 20 June 1990 that occurred in the northern province of Iran, Sefid-rud concrete buttress dam located near the epicenter was severely shaken. The crack penetrated throughout the dam thickness near slope discontinuity, causing severe leakage, but with no general failure. In this study, nonlinear seismic response of the highest monolith with empty reservoir is investigated experimentally through model testing. A geometric-scaled model of 1:30 was tested on a shaking table with high-frequency capability to study dynamic cracking of the model and serve as data for nonlinear computer model calibration. Three construction joints are set up in the model to... 

Rock samples from the Asmary outcrop formation of the Ahwaz oil rich zone with a porosity of 16% and permeability of 1 md and MIS crude oil with an API value of 42.5 and moderate asphaltene content of 3%, were used to study the effect of the incubation time and flow rate of the displacing fluid in MEOR operations. Five species of rod shaped, gram positive, thermophile and facultative bacteria were isolated and purified from the crude. Due to the high sweep efficiency prevailing in the core flooding system, the effect of the displacing brine flow rate on the oil recovery efficiency was found not to be significant. On the other hand, a 100% increase in incubation time from 7 to 14 days... 

A mesophilic iron oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated (33°C) from a typical chalcopyrite copper concentrate of the Sarcheshmeh Copper Mine in the region of Kerman located in the south of Iran. In addition, a thermophilic iron oxidizing bacterium, Sulfobacillus spp., has been isolated (60°C) from the Kooshk Lead and Zinc Mine near the city of Yazd in the mid-west region of Iran. The variation of pH, ferrous and ferric concentration and cell growth on the time and effects of some factors, such as temperature and initial ferrous concentration, on the bioleaching of chalcopyrite concentrate obtained from Sarcheshmeh Copper Mine, were investigated. Bioleaching... 

This paper describes an attempt to develop congestion indices for a developing country with a limited sampling. Speed and flow rate information was collected from urban highway traffic flow videotaping in Iran. Video display provided information for traffic modeling when, similar to most of the developing nations, Iran does not have locally developed highway capacity manuals. Processing of the extracted data and traffic modeling provided free and capacity flow information for the selected freeway and principal arterial sections for the capital city of Tehran. The congestion indices were associated, in simple and logical models, with five traffic descriptive variables of travel speed, travel... 

Sarabs (spring-fed pools) are an important natural freshwater resource in Iran where they are used for potable, agricultural and recreational purposes. A survey of 17 Sarabs was undertaken in the Province of Kermanshah to obtain data on their water quality and biology which would help inform future management of these multifunctional resources. These Sarabs differed greatly in size (50-30000m2 surface area) and were situated at altitudes of between 622 and 1697 m above sea level. The average dissolved oxygen content and pH of the water was between 4.5 and 10mg O2/1, and 6.95 and 7.6 respectively. The Sarabs differed particularly in their dissolved solids content from 100μS/cm (detectable... 

Implementation of green management in sport complexes can ensure the continuous arrangement and assessment of activities from the environmental perspective and will end up in control and prevention of contaminants. Enghelab sport complex (ESC) in Iran is selected for this study due to its size and long-term activities. Due to the comprehensive plan of the aforesaid sports complex, numerous centers and departments were established in this site in order to materialize its envisioned sports, recreational and cultural objectives. The results of the questionnaires distributed amongst the members and the personnel of the complex revealed that approximately 50 % occupants were not acquainted with... 

Truck accidents are an issue of concern due to their severity. Logit modeling and Neural Network modeling are performed to investigate factors such as vehicle, roadway, environment and driver characteristics that can potentially contribute to the severity of truck accidents. The objective of this study is to present models that can predict the severity of truck accidents and to identify the important factors causing these accidents. Comparison between neural networks and logit modeling are made using vehicle crash data on two-lane rural highways in Iran. A variety of variables related to roadways, vehicles, environment and drivers, such as, driver fatigue, head-on collision and lack of... 

In this paper a general method for system level prediction of INL in pipeline analog to digital converters is presented. For each stage of the ADC, a new error model consisting of an input referred gain error and a nonlinear term is introduced. An analytic method to calculate INL from all error sources is presented. INL model for a switched-capacitor implementation is also presented. ©2006 IEEE  

This paper presents a new class AB circuit for current-mode signal processing. These current mirrors are especially designed for advanced CMOS technologies and low-voltage high-speed applications. As an example two current amplifiers with a gain of 2, settling time of less than 6ns and current consumption of 500μA are designed and simulated. ©2006 IEEE