Sharif Digital Repository

In this paper, the interaction between various window specifications and different climate conditions is investigated. For this purpose, simultaneous effects of several aspects including glazing system, glass type, filling gas, glass thickness, window frame fraction, and interior shading are considered under three different climatic conditions. To evaluate the energy performance of various considered alternatives, the energy simulation of a base case building is evaluated in a computer environment. Using the validated model, the energy analysis is quantitatively performed, and cost-benefit analyses from the viewpoints of both residents and government are carried out based on the domestic and... 

In this research, a site selection method for wind-compressed air energy storage (wind-CAES) power plants was developed and Iran was selected as a case study for modeling. The parameters delineated criteria for potential wind development localities for wind-CAES power plant sites. One important consequence of this research was the identification of the wind energy potential for wind-CAES sites. The theoretical wind energy potential of Iran of greater than 50 W/m2 was identified from a wind atlas of Iran. The model produced factor maps by considering the boundary conditions of the input data and created geo-databases from the outputs maps. The main factor maps were electrical grids and... 

The aim of this study is to investigate the effect of the rock brittleness indexes on the specific ampere draw of the circular diamond saws. In this study, twelve rock types belonging to granite and carbonate rock were cut with two different types of circular diamond saws on a fully instrumented laboratory-sawing rig at different feed rate and depths of cut. Rock samples were collected from factories from Iran for laboratory tests and uniaxial compressive strength and tensile strength were determined. The brittleness of B 1 (the ratio of compressive strength to tensile strength), B 2 (the ratio of compressive strength minus tensile strength to compressive strength plus tensile strength), and... 

The main purpose of this study is to compare the many different rock properties in the rock sawability. The comparison was realized with the combination of the analytic hierarchy process (AHP) and Fuzzy Delphi method and also TOPSIS method. The analysis is one of the multi-criteria techniques providing useful support in selecting among several alternatives with different objectives and criteria. FDAHP method was used in determining the weights of the criteria by decision makers and then ranking the sawability of the rocks was determined by TOPSIS method. The study was supported by the results obtained from a questionnaire carried out to know the opinions of the experts in this subject.... 

The current paper deals with the energy generation system utilizing three kinds of renewable energy solar, ocean thermal, and wind energy with climatic circumstances near regions with higher potential for the ocean thermal energy conversion system with suitable conditions based on solar radiation and wind speed as a source of energy. The suggested system is evaluated using a beach welfare complex based on the total daily electricity. The system’s main components included a Rankine organic cycle, turbine, pump, thermoelectric, a flat plate solar collector, heat exchanger, and wind turbine. EES software was utilized to simulate the system and acquire thermodynamic results. For areas with good... 

A 37 dBm power amplifier (PA) is designed on a 0.25 μm optical T-gate pseudomorphic high electron mobility transistor (pHEMT) technology. The design of this two-stage PA along with a step-by-step design procedure is presented in this paper. This methodology can be used for design of PA in different technologies and frequencies. The PA delivers 5 W output power over the frequency band of 13-19 GHz. It shows average power-added efficiency of 37% and large signal gain of 15 dB in measurements which is consistent with simulation results. The output power and efficiency of the realised amplifier reach maximums of 37.6 dBm and 45%, respectively. Considering output power, bandwidth, chip area and... 

Quartz is usually detected as an impurity of kaolinite clays. The present work attempts to evaluate the role and behaviour of quartz particles in geopolymerisation and its probable effects on mechanical behaviour of geopolymeric products. Two kaolinite clays with different free quartz contents were used as raw materials to produce geopolymers. Results showed that using high content quartz kaolin causes higher compressive strength. Scanning electron microscopy studies confirmed that quartz does not participate in geopolymerisation and completely remains in the structure as fine particles. High hardness quartz particles by retarding crack growth in the geopolymer matrix enhance mechanical... 

MapReduce and its open source implementation, Hadoop, have gained widespread adoption for parallel processing of big data jobs. Since the number of such big data jobs is also rapidly rising, reducing their energy consumption is increasingly more important to reduce environmental impact as well as operational costs. Prior work by Mashayekhy et al. (IEEE Trans. Parallel Distributed Syst. 26, 2720–2733, 2016), has tackled the problem of energy-aware scheduling of a single MapReduce job but we provide a far more efficient heuristic in this paper. We first model the problem as an Integer Linear Program to find the optimal solution using ILP solvers. Then we present a task-based greedy scheduling... 

This paper provides empirical evidence on a novel complementarity between VAT and trade taxes. Downstream domestic firms require VAT receipts from importers to claim VAT on purchases, increasing incentives for honest reporting of imports. Trade gap, the difference between mirror and domestic trade reports in Iran at 6-digit HS disaggregation, is used to measure this complementarity. Iran introduced VAT in 2008 and, since then, has increased its rate from 3 to 9 percent. Difference-in-differences estimates show that a 1 percentage point increase in the VAT rate reduces the trade gap by about 2 percent. Consistent with the compliance mechanisms for VAT, a smaller effect for consumer products... 

Water supply challenges are caused by population growth, industrialization, as well as the scarcity of freshwater resources. Low-grade waste heat-driven seawater desalination technologies may improve the water-energy nexus issues of desalination systems by different configurations. The data envelopment analysis is used to determine the best final decision to achieve a better comparison of different parameters. The optimal configuration of low-grade waste heat driven seawater desalination is studied using flue gas waste heat in heat recovery boilers of an industrial oil refinery. Nine different types of multistage flash and multi-effect distillation (MED) desalination plants have been... 

A very efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, allylic, benzylic, secondary, hindered secondary, tertiary, and phenols with hexamethyldisilazane on the surface of silica gel dispersed with LiClO4 in room temperature at few minutes in excellent yields under neutral conditions is reported. This procedure also allows the excellent selectivity under LP-SiO2 system for silylation of alcohols in the presence of amine and phenolic hydroxy groups  

Enzymatic decolorization of the monoazo dye, acid orange 7 (AO7) by the fungal peroxidase from Coprinus cinereus NBRC 30628 is a complex system, which is greatly affected by temperature, pH, enzyme activity and the concentrations of H2O2 and dye concentration. The study of these factors and investigating the combined interactions between them by applying one-factor-at-a-time (OFAT) method and two other statistical methods including 2-factorial method and response surface methodology (RSM) were aimed in this work. Through OFAT analysis the optimized conditions were a temperature of 25 °C, pH 9.0 with H2O2 concentration of about 3.9 mM and AO7 concentration of 40 mg/l. A complete...