Sharif Digital Repository

The competitiveness of a port convinced shipping lines and shippers with a significant basis in selecting a port. Port authorities and port operators can make use of the competitive advantage as a parameter for counter measures by grasping the advantages and disadvantages of the ports and be a prime factor of opportunities and threats of the ports. Ports have a significant role in today’s networked business environment. They are being regarded as hubs that are part of various logistic systems. The very essence of a seaport is to link maritime networks and land network. These networks for the port are means of analyzing its competitiveness. A port overall competitiveness is determined by it’s... 

High advantages of hydrometallurgy have led to its recent development in metal extraction. Many investigations are being carried out on applying hydrometallurgy processes on copper extraction. In this study, the chloride leaching of chalcopyrite in a concentrated sodium chloride solution (4M) –which is a novel process–, using CuCl2 as leachant is investigated. Main effects and interactions of temperature (50–90°C), time (2–6 hr), CuCl2 concentration (0.1–0.5M), pulp density and HCl concentration (0.1–1M) at constant stirring rate (600 rpm) on leaching is studied using 2k factorial design and applying Design–Expert 7.0.0 software. While the effect of pulp density is almost negligible,... 

The development of new wrought magnesium alloys for automotive industry has increased in recent years due to their high potential as structuralmaterials for low density and high strength/weight ratio demands. However, the poor mechanical properties of the magnesium alloys have led tosearch a new kind of magnesium alloys for better strength and ductility.In this research,a new type of magnesium alloy based on Mg-Zn-Si-Ca system has been developed using the permanent gravity casting process. For comparison, an alloy without Siby the same method was also produced. The effects of trace Si addition on the microstructure and mechanical properties in magnesium alloy with composition of... 

Pre-reduction of some manganese sources (low-grade Venrach and Godar-Sabz ores, high-grade Comilog ore, pellet, pure oxide) by methane gas has been investigated in this research. HSC-Chemistry and FactSage software were used for thermodynamic study of the process. Thermodynamic results indicated that methane may progress to manganese carbide formation, and the reduction process can run autonomously involving less carbon dioxide emission comparing to common ferromanganese process. Several techniques including XRF, XRD, in-situ XRD, SEM-EDS, and thermogravimetry were used in sample characterization and experiments. In addition to the thermal decomposition reactions which were affected by... 

Estimating electricity demand elasticity in different sectors has been an essential research topic. Considering the fact that pricing electricity in various countries does not follow the same rules, many econometrics methods have been developed to estimate this crucial parameter. Electricity demand elasticity is defined as the percent change in electricity consumption in response to one percentage change in electricity price. Having a correct estimate of this parameter would help policymakers to price electricity properly in order to reach desirable goals in electricity consumption optimization and many other aspects of electricity consumption. In Iran, Tavanir Co. which is a subsidiary of... 

Quantum memory which stores the coherent information of logical qubits, is an essential ingredient of quantum information processings. Each logical basis should be encoded on macroscopically distinct physical states since otherwise the indistinguishability of logical bases is easily destroyed by local errors.On the other hand, the memory must be able to have superposition of macroscopically distinct states of physical qubits. To maintain such superposition is very difficult. First, if the size of the memory is infinite, such macroscopic superposition is impossible since superposition of different phases is just a classical mixture of them in an infinite system. Second, even in finite... 

Nowadays, the development of different polymer blend nanocomposites is of great importance for achieving electrical and antistatic properties for various applications such as auto parts and the packaging industry. Immiscible polymer blends with conductive nanoparticles such as carbon nanotube, graphene, etc. can reach the conductivity threshold with low amounts of nanoparticles and produce desired electrical properties. In the present study, we have attempted to develop a polystyrene(PS)/ethylene-octene copolymer(EOC)/carbon nanotube(CNT) blend nanocomposite with suitable electrical conductivity. The compounding was performed by melt mixing at two weight percent of 80/20 and 50/50 (PS/EOC)...