Sharif Digital Repository

Using two different capacitive cell probes; and monitoring capacitance and resistance values of the air and water liquids, the cell length and conductance effects of the water liquids are studied. Variations of the dielectric air capacitance and reactance capacitance parameter of liquids with cylinder length are investigated. In another study the probe length affects on the capacitance and resistance measurements for the liquid filling process are investigated. Different theories are also developed to calculate the capacitance values for the constructed probes. Capacitance per unit length from the Coulomb theory is different from the Gauss law that is a constant value. Measured air... 

The purpose of the research is to define and analyze the dominant organizational culture in Kish and to conduct a pilot research in Iran. Designed as a survey, the research employs the five cultural dimensions of Hofstede in organizations, and by different methodology, defines the ranking of each dimension. The sample consists of 254 employees working in two public and five private organizations on Kish-Island. In addition to define the ranking for each of the five dimensions, for the first time in Iran, the survey measures the ranking of long-term orientation, and shows differences between dominant culture in Iran and the Arab countries (opposed to Hofstede's recommendation). The... 

Cooling system is essential for high power fuel cells to maintain cells temperature in an acceptable limit. In this paper a suitable cooling system for the PEM fuel cell has been designed and optimized. The design includes the number of the cooling plates, the proper circuit of the cooling channels in the plates, the channel dimensions, the flow rate of the cooling fluid and its temperature. The optimization technique is minimization of the entropy generation through the cooling plates. The design of the cooling channels and plates is such that the plate temperature doesn't exceed from a desired temperature and the temperature variation in the plate becomes minimized. In this design, the... 

In traditional game theory, the players play with policy of maximizing their payoffs. In real world, there are many situations where payoffs have uncertainty and are fuzzy in nature. In this paper, a new method for finding pure strategy Nash equilibriums, to realistically analyze the games with fuzzy payoffs is investigated. Using ranking fuzzy numbers, a fuzzy preference relation is constructed over payoffs. The priorities of payoffs are considered as the degree of being Nash equilibriums  

This study aims to investigate, optimize, and simulate the dispersed phase holdup at flooding conditions for the standard physical systems in a pulsed extraction column with the disc-doughnut configuration. The interaction impacts for operational parameters (pulse intensity and organic and aqueous phase velocities) and interfacial tension (systems type) were examined using the response surface approach. A novel correlation for the dependent parameter, namely holdup at flooding based on the quadratic model, was developed with the central composition design methodology. A desirable agreement between actual data and calculated data from the proposed model was observed because of the high... 

Single nucleotide polymorphism (SNP) in human genomes is considered to be highly associated with complex genetic diseases. As a consequence, obtaining all SNPs from human populations is one of the primary goals of recent studies on human genomics. The two sequences of SNPs in diploid human organisms are called haplotypes. In this paper, the problem of haplotype reconstruction from SNP fragments with and without genotype information is studied. Minimum error correction (MEC) is an important model for this problem but only effective when the error rate of the fragments is low. MEC/GI, as an extension to MEC model, employs the related genotype information besides the SNP fragments and,... 

Cell temperature in fuel cells is an important parameter which highly affects fuel cell stack efficiency. A suitable cooling system should satisfy an acceptable temperature range. In this research a relevant cooling system for a specified PEM fuel cell stack has been proposed complying with the criteria and cooling requirements of the fuel cell. The effect of various parameters on the entropy generation and temperature distribution in the cooling plates are surveyed. The number of cooling plates, the number of channels in each cooling plate and the channel width is determined. Two flow regimes namely laminar and turbulent flows of the cooling fluid in channels are analyzed and a design... 

Earlier, we engineered a wireless power transfer (WPT) system whose key element is a self-activating and self-decoupling transmitting (Tx) antenna called the high-impedance coil (HIC) that grants a high efficiency for a receiving (Rx) antenna with a free position in front of the Tx array. When the Rx antenna is located in front of the Tx one, the input impedance of the last one drastically decreases, which results in efficient power transfer. This impedance is initially so high that the Tx antenna in the absence of the Rx one does not accept power, which implies negligible open-circuit losses. This feature grants the automatic activation/deactivation of the WT system. In the present work, we...