Sharif Digital Repository

The paper aims to investigate the importance of firms’ financial constraints for pricing equity in Iran. We study the impact of financial constraints of non-financial firms on their stock returns using a sample of 241 manufacturing firms listed in Tehran Stock Exchange (TSE) for the period of 2007 to 2014. We use a similar index as in Kaplan and Zingales (1997), KZ, to measure financial constraint. We examine whether financial constraint influences stock returns and can improve the explanatory power of the Fama and French three-factor asset pricing model. Our findings indicate that financial constraints can be considered as an important factor affecting asset returns. Cross-sectional... 

Human as an important part of the natural environment and can exert their positive or negative effects in the form of long-term and short-term on a natural environment. Human impacts on the natural system are very complex and consist of various components. The most considerable among them from past to now are maybe land use and land cover change, although, the impact of dam construction, water pollution, air pollution and etc, can not be neglected. To quantify the impact of these changes, many researchers have studied meteorological and climatic parameters using statistical relationships, but one major problem always existed, the low spatial accuracy of meteorological data. In recent years,... 

The competition between producers and the contracts issues between the producers and consumers of electrical energy in restructured power systems might cause on unwanted increase in power interchange beyond transmission lines capacity. If the power interchange is not well-managed, it would often cause overloads in specific path. This phenomenon is termed as lines congestion. The major goal of congestion management is to create a set of rules that ensure sufficient control over producers and consumers to maintain an acceptable level of power system security and reliability in the time of limitation of transmission network with maximizing economic market efficiency. As FACTS devices provide... 

In this study, effect of chelate ligands containing carboxylic, phenolic, and amine functional groups on the synthesis of related-perovskite Ca2Fe2O5 versus perovskite CaFeO3 structures have been investigated. Herein, the application of chelating-agent method, e.g. EDTA, Citric Acid, NTA, malonic acid, maleic acid, catechol, acetylaceton, p-tert-butycatechol, aminophenolic derivative ligand, and 2-hydroxyiminodiacetic acid, in comparison to co-precipitation method was also undertaken. The crystalline structure of the obtained perovskites were compared with those of co-participation method in solid state. Experimentally, it was found that the related XRD bands for CaFeO3 were appeared in the... 

Electrochemical treatment of tumors introduces cancer therapy method that uses direct current which passes through cancer tissue. The manipulated variable (direct current density) is applied to the surface of the electrode. As a result of applying direct current on the anode's surface, two competition reactions start to happen on the electrode's surface, Chlorine and Oxygen evolutions. The productions of these two reactions for instance Cl_2 , Cl^- and H^+ caused different reactions in the domain of the electrolyte which is the body tissue. According to the buffer characteristic of blood and organic features of tissue, various types of acids like HClO form in the electrolyte. If the pH in... 

In the past decades, hydrogels have been used as an adsorbent with high potential to remove pollutants in water. Hydrogels are three-dimensional polymer networks that have the ability to absorb and store water and water-soluble compounds due to the presence of hydrophilic functional groups in their structure. Different particles with unique characteristics can be used to increase the efficiency of hydrogel absorption. Based on the type of pollutant, hydrogels are divided into three different forms, including particles, films and nanocomposites. In this research, the absorption effect of metal cations as well as the absorption kinetics of polyvinyl pyrrolidine-based hydrogels, sodium... 

Since the classical continuum theory fails to deal with the problems associated with defects, stress concentrators, and relevant deformation phenomena in solids, alternative approaches that can detect the atomistic nature of materials' fracture are required. The deficiency of the capture the size effect which yields delusively high values for some components of the stress field right on the edge of the stress concentrators, and its weakness in describing the complex interaction between small inhomogeneities, cracks and the like when they are only a few nanometers apart, are among some of the disadvantages of the classical approach. In recent years, however, atomistic methods are emerging to... 

Aluminum Bronzes have many applications in marine environments. These alloys suffer from both hot cracking and cold cracking. In order to overcome the hot cracking and cold cracking, Semisolid Stir Joining method and a proper thermal cycle was used respectively. Effects of temperature, stirring rate, and tool type were investigated in Semisolid Stir joining method. In this method, butt joint design was used in order to place specimens, and the specimens were heated up to specific temperatures (920, 925, 930°C). A stirrer (Cylindrical and Grooved tool) with three rotational speeds (800, 1200, 1600 RPM) was introduced into the stir weld seam. Welded specimens were cooled to the 900°C... 

The low female labor force participation rate in the Iranian labor market relative to the global average and even to countries that do not differ significantly from the socio-economic characteristics of our country is one of the important questions of the Iranian labor market. In this study, we seek to answer the question of whether the economic participation rate of married women will increase if the gender gaps in wages, job findings and job losses among women and men are eliminated in the Iranian labor market. To answer this question using household expenditure and income data and labor force data, we show that between the two categories of occupations, in terms of the share of women's... 

Shot peening is a cold-working process commonly used in industry to improve the fatigue performance, stress corrosion resistance and surface nano-crystallization of metallic parts. This process extends fatigue life via two mechanisms: Preventing the crack growth due to compressive residual stresses and, preventing the crack initiation because of increased material hardness. These mechanisms are the results of the bombardment of the component's surface with small spherical particles. In this research, an analytical model is developed for estimating the residual stress distribution induced by shot peening process. The modifications of the developed analytical model are related to... 

Solid-State Drives (SSDs) provide high performance, low power consumption, and hence are widely used in the I/O cache of enterprise storage systems and high performance servers. Although employing high performance SSDs in the I/O cache of storage systems significantly improves system performance, it comes with significant reliability threats for write operations upon power failures. In order to provide high level of reliability, storage architectures employ SSDs in I/O cache with RAID-1 configuration, however, such configuration only partially mitigates the reliability issues of the SSDs. In this thesis, we analyze the reliability of SSD-based I/O caches against power outage and high...