Sharif Digital Repository

Nanolaunchers are launch vehicles capable of carring light payloads (under 50 kg) to Low Earth orbit and received much attention in the few past years. Launching the nanosatellites grown about 30 times from 2008 to 2017. Since this category of launch vehicles has fewer developing costs and lower thechnology level, they fit developing space technology in our country. Conversely, the demand of high propellant mass fraction and specific impulse may be a serious difficulty to attain this technology.The only operating nanolauncher in the world is SS-520-5 which belongs to Japan and is a three-stage solid propellant launcher. The goal of this project is also the conceptual design and feasiblity... 

This research focuses on the topic of international portfolio diversification and its core attention is entitled to Middle East stock exchanges, as emergent markets. These markets are not analyzed yet as investment destinations for developed countries investors. Although all methodologies in this research are applied on ME markets data, but can be augmented and generalized for other markets. In this quest, we tried to investigate portfolio diversification opportunity for European (generally Frankfurt & Paris stock exchanges) or American investors with ME stock exchanges including Tehran, Istanbul, Saudi Arabia Tadawul, Abu Dhabi & Cairo stock exchanges, in order to reduce risk and increase... 

Despite a rather long history of bureaucratic public administration, Iranian public sector has failed to catch up with the ever developing knowledge of fighting corruption in “public procurement”, a critical field of governmental management which accounts for at least 15 percent of GDP around the world. While international organizations like TI and OECD have been broadly active in globalizing the standards of integrity and calling for improvements in the national frameworks of procurement, a reductionist agenda might take the safest path of change by following whatever prescribed by those international bodies. However, there have also been some deeper reflections on the complexities of... 

In this research, uranium is leached from pHospHate ore of Sheikh Habil region by leaching operation using leaching agent (sulfuric acid) along with production of pHospHoric acid. In the following, the production of yellow cake from the produced liqueur solution (pHospHoric acid) by solvent extraction process is also mentioned. PHospHate ore contains a large amount of calcite and dolomite, which removal of these annoying elements by wet, dry and acid washing methods is the key to success in the production of pHospHoric acid. For this purpose, in the wet method of a flotation system, the dry method of heat furnace and in the acid washing method, various organic and inorganic acids were used... 

In this research, trade and transportation trends of Asia-Europe-Africa, in the both intercontinental and intracontinental levels have been analyzed. With analyses which are done in this research, determinant factors for modeling and investigating international bilateral trade in these three continents have been recognized. The relevant time-series data were extracted from centralized and international databases. The examined database consists of 11 variables grouped in four categories: bilateral trade data, transportation, geographical and socio-economic characteristics. Transportation data is based on three different networks. The first network consisted of highway, rail and marine modes... 

The present work was aimed to account a green and eco-friendly synthesis of copper oxide nanoparticles using Salvia hispanica extracts for the first time.The synthesized copper oxide nanoparticles were fully characterized using FT-IR, XRD, FESEM, EDX, TEM and UV-Vis spectroscopy techniques. The average particle size of copper oxide nanoparticles is around 35 nm and shape of nanoparticles are spherical. Biological activity of the synthesized nanoparticles were evaluated in terms of antibacterial assessments against Staphylococcus aureus and Escherichia coli. In the following, the potential antibacterial activity against gram positive (S.aureus) and gram negative (E.coli) bacteria’s were... 

Many aroma compounds of fruit juice recovered by thermal processes like evaporation and distillation can lead to undesirable chemical changes and even their loss. Pervaporation is a promising process for the recovery of volatile organic compounds from their aqueous solutions. In the present work, pervaporation recovery of Butyl acetate as a model solution ofgrape juice aroma compoundwas evaluated with polyethersulfone (PES) and ethylvinylacetate (EVA) membranes. PES membrane generally showed better selectivity so that the separation factor at the concentration of 500 ppmand the temperature of 30°C for PES and EVA membranes, respectively, was 230.78 and 156.9. The effect of two operating... 

Investigation of reservoir performance and long-term production prediction are main goal of numerical simulation. Numerical simulation mainly consists of solving sets of non-linear equations developed by combination of continuity equation, equation of state and Darcy equation. Classical methods such as finite difference method (FDM), finite volume method (FVM) and finite element method (FEM) are widely used for solving sets of fluid flow equations that mentioned above. Researchers have used other methods like boundary element method recently. Each of these methods has their own restrictions. But the main source of error in these methods is due to numerical estimation of spatial derivatives...