Sharif Digital Repository

A process of ethanol production from wheat straw in Iran was simulated using SuperPro Designer. Wheat is the main cereal crop in Iran. Khuzestan Province was selected as a potential location for the construction of plant. A method was developed to estimate the plant capacity. The base plant size in Khuzestan was estimated to be 316 t day−1. The effect of plant size, logistics of residue collection, wheat yield, and agreements with local farmers on the profitability was calculated, and the minimum selling price was determined for different scenarios. In addition, the sensitivity analysis and economic risk assessment were conducted. The operating cost was mainly sensitive to the wheat straw... 

Here, the design of a wideband absorber operating at terahertz frequencies is presented. The design is based on an analytical circuit model of graphene arrays of rectangular patches obtained from the presented circuit model of graphene arrays of disks. A recently proposed method is generalised for the design of wideband absorbers at higher frequencies The bandwidth is increased by correct tuning of the input impedance for a structure composed of two layers of graphene arrays and a metal-backed dielectric layer. Using two-layer graphene arrays, the authors decrease the slope of the imaginary part of the input impedance to increase the bandwidth. The designed absorber works at a frequency of... 

This research proposes a large deformation, time-dependent viscoplastic constitutive relationship to enhance the prediction of the compaction degree of asphalt concrete materials under laboratory and field conditions. A large-deformation thermodynamic-based framework is presented. The Helmholtz free energy and rate of energy dissipation functions were assumed to derive rate-dependent constitutive relationships to relate multi-axial state of stresses to the recoverable and non-recoverable deformation response of asphalt concrete during compaction. A straightforward method that allows the calibration of the proposed model against laboratory compaction data (e.g., data from Superpave Gyratory... 

In the present study, an attempt was made to investigate the potential of some of the major world’s crops, including wheat, corn, rice, barley, sugarcane, sugar beet, potatoes, and oats, to produce biohydrogen. The collectable amount of agricultural residues that could especially be used to produce hydrogen was estimated in Africa, Asia, Central America, Europe, Northern America, Oceania, and South America, and the potential amount of ammonia as the main nitrogen fertilizer was estimated. Double exponential smoothing method was employed to forecast the future crop production and area harvested. It was calculated that about 10.56 (in 2013) and 15.5 (in 2030) Mt of biohydrogen and 59.84 (in... 

In the present study, an attempt was made to investigate the potential of some of the major world’s crops, including wheat, corn, rice, barley, sugarcane, sugar beet, potatoes, and oats, to produce biohydrogen. The collectable amount of agricultural residues that could especially be used to produce hydrogen was estimated in Africa, Asia, Central America, Europe, Northern America, Oceania, and South America, and the potential amount of ammonia as the main nitrogen fertilizer was estimated. Double exponential smoothing method was employed to forecast the future crop production and area harvested. It was calculated that about 10.56 (in 2013) and 15.5 (in 2030) Mt of biohydrogen and 59.84 (in... 

A process of ethanol production from wheat straw in Iran was simulated using SuperPro Designer. Wheat is the main cereal crop in Iran. Khuzestan Province was selected as a potential location for the construction of plant. A method was developed to estimate the plant capacity. The base plant size in Khuzestan was estimated to be 316 t day−1. The effect of plant size, logistics of residue collection, wheat yield, and agreements with local farmers on the profitability was calculated, and the minimum selling price was determined for different scenarios. In addition, the sensitivity analysis and economic risk assessment were conducted. The operating cost was mainly sensitive to the wheat straw... 

In the present study, an attempt was made to investigate the potential of some of the major world’s crops, including wheat, corn, rice, barley, sugarcane, sugar beet, potatoes, and oats, to produce biohydrogen. The collectable amount of agricultural residues that could especially be used to produce hydrogen was estimated in Africa, Asia, Central America, Europe, Northern America, Oceania, and South America, and the potential amount of ammonia as the main nitrogen fertilizer was estimated. Double exponential smoothing method was employed to forecast the future crop production and area harvested. It was calculated that about 10.56 (in 2013) and 15.5 (in 2030) Mt of biohydrogen and 59.84 (in... 

Abstract- Benefits of PSS application for electromechanical oscillations damping is clarified. A major difficulty of PSS application is its tuning such that its damping characteristics do not fall into overcompensation facing continuously changing power systems. This paper presents an approach for wide area monitoring and control based PSS tuning. The presented approach originated from adaptive tuning based on real time power system state estimation. © 2008 IEEE  

Operation of transmission lines are usually limited by stability limits rather than thermal capacity limits. Thermal limit of transmission lines is a physical limitation of their components and not related with the overall power system characteristics, but stability limits are strictly related with power system characteristics. This paper presents an approach for increasing stability limits using PSS. © 2008 IEEE  

Montmorillonite K10-supported manganese(II) chloride was found to be an efficient and convenient catalyst for the oxidative cleavage of oximes, phenylhydrazones and semicarbazones to the corresponding carbonyl compounds with molecular oxygen. © 2006 Bentham Science Publishers Ltd  

In this article, an attempt is made to utilize the exhaust gases of a small gas turbine to augment power output through the employment of a thermoacoustic system. A simple gas turbine cycle is selected as the base cycle and it is assumed that the thermoacoustic system is powered only by the waste heat of the base gas turbine. A comprehensive cycle analysis of the integrated gas turbine thermoacoustic engine (IGTTE) is carried out from an energy and exergy point of view. Exergy efficiency and internal exergy efficiency are calculated for the different components of the base gas turbine engine as well as the IGTTE. Value and exergy flow diagrams are used to investigate the possible... 

In the present work, we report a chemically modified polyacrylamide/silica nanoporous composite adsorbent for the removal of reactive black 5 (RB5) azo dye from aqueous solutions. The composite adsorbent was synthesized in a packed bed and modified by ethylenediamine (EDA). The adsorbent was characterized by Fourier transformation infrared (FT-IR), thermogravimetric analysis (TGA), thermoporometry, Brunauer, Emmett and Teller (BET) method and scanning electron microscopy (SEM). Mechanical stability of the adsorbent was examined in a packed bed by following the back-pressure of the column. Pore diameter of the composite adsorbent in dry and wet states was estimated to be about 18.71 nm and... 

Oxy-fuel firing is more energy efficient and environmental friendly than conventional air-fuel firing and its application to reheating furnaces has hegun since 1990s. A computational method was presented to predict the steady heat transfer to the billets and temperature distribution in a continuous pusher type reheating furnace in which combustion air was enhanced by oxygen. Radiation heat flux calculated from the radiation heat exchange within the furnace was modeled using the FVM considering the effects of furnace walls and billets. Energy consumption per ton of steel, production rate and thermal efficiency of furnace, and trend of NOx emission in various levels of oxygen enrichment were... 

Fracture tests on Sn93Pb37 solder joints in a double cantilever beam (DCB) configuration were performed at two different strain rates of 10−5 and 0.03 s−1 under mode I loading conditions. In each case, the critical strain energy release rate for crack initiation, Jci, was obtained. Effects of storing specimens at a constant temperature of 75 °C and cyclic temperature varying between 32 and 75 °C were examined at these strain rates. In the strain rate of 0.03 s−1, storing samples in a constant or cyclic temperature caused the fracture energy to decrease significantly with respect to the specimens maintained in ambient temperature. The significant reduction in fracture energy by placing the... 

Double cantilever beam (DCB) specimens were prepared according to standard surface mount technology (SMT). The samples were stored inside an environmental chamber at two different relative humidity values (i.e. 40 or 100%) for either 2 or 4 h. Then they were aged at 25 °C, 75 °C or 125℃ for the same time. Finally, after being cooled to room temperature, fracture tests were performed under mode-I loading conditions at a strain rate of 0.03 s−1 at room temperature. Storage time did not have a significant effect on the fracture behavior. The fracture load and energy of the solder joints decreased significantly when the temperature was increased from 25 to 75℃. By further increase in the... 

This paper presents mathematical modelling of joint lot sizing and scheduling problem in job shop environment under a set of working conditions. The main feature of the problem is to deal with flexible machines able to change their working speeds, known as process compressibility. Furthermore, produced items should be assembled together to make final products. In other words, the products have a multilevel structure, shown with bill of materials. As the problem is proved to be strongly NP-hard, it is solved by a memetic algorithm here. Computational experiences on the data of Mega Motor company are reported. Also, further experiences on random test data confirm the performance of the... 

Background While several studies have investigated the traditional linear measures in patients with knee osteoarthritis, no study has yet reported the non-linear structure of postural sway in these patients. Methods We used two non-linear methods, recurrence quantification analysis (percent of determinism-%DET) and central tendency measure, to respectively investigate differences in the complexity and variability of sway dynamics between two groups of knee osteoarthritis patients (n = 27) and healthy controls (n = 27) under different conditions of postural and cognitive tasks. The experimental conditions included standing on (1) rigid surface with open eyes; (2) rigid surface with closed... 

Diffusivity equation which can provide us with the pressure distribution, is a Partial Differential Equation (PDE) describing fluid flow in porous media. The quadratic pressure gradient term in the diffusivity equation is nearly neglected in hydrology and petroleum engineering problems such as well test analysis. When a compressible liquid is injected into a well at high pressure gradient or when the reservoir possess a small permeability value, the effect of ignoring this term increases. In such cases, neglecting this parameter can result in high errors. Previous models basically focused on numerical and semi-analytical methods for semi-infinite domain. To the best of our knowledge, no... 

Increasing grid integration of intermittent renewable energy sources (RESs) and plug-in electric vehicles (PEVs) with uncertain behaviours have necessitated enhancing the flexibility requirements of distribution networks. Thus, in the state-of-The-Art distribution network expansion planning (DNEP) models, both flexibility requirements and high penetration of RESs and PEVs should be taken into consideration. In this respect, a novel collaborative planning model for power distribution network (PDN) and plug-in Electric Vehicle Parking Lots (EVPLs) is proposed in this paper, which leverages sizing, siting, and operation of EVPLs to enhance the distribution network flexibility. Also, to model...