Sharif Digital Repository

Anaerobic digestion processes and the conductive electron transfer approach were used to describe the bioenergy production processes in a microbial fuel cell (MFC), respectively. The present model is a far more completed form of conduction-based modeling which is able to predict performance of an MFC fed with complex substrates and inoculated with multi-population culture. One-dimensional spatial distributions of the different microorganisms, as biocatalysts of processes and intermediates produced in the different steps of the anaerobic digestion processes in the biofilm, as well as the dynamic behavior of the anolyte including syntropic interactions among different groups of microorganisms... 

In this study, a new model of microbial fuel cell (MFC) was obtained for the first time. The modeled MFC was made using a combination of two approaches; the conduction-based method and two-step anaerobic digestion. Performance of the MFC was based on calculations for current evolution and polarization curves with different subsequent variables of the biofilm and anolyte. The model was able to make predictions for performance of the MFC for a simple substrate to more complex ones. The model was successfully validated with a variety of substrates (acetate, glucose and dairy wastewater) and the results were compared with previously published measurements. The model polarization results showed... 

The objective of this study was to construct a novel model to be applied in a general manner to simulate microbial electrochemical cells (MXCs); for both microbial fuel cell (MFC) and microbial electrolysis cell (MEC). The liquid bulk was modeled based on the organic matters degradation to acetate via the anaerobic digestion process. Biofilm simulation was established based upon one-dimensional distribution and the dynamical electron transfer was completed by means of the conduction-based mechanism. We, for the first time, introduced biofilm local potential modeling for MEC simulation with general and simplified linear boundary conditions. The MFC-related part of the model was evaluated... 

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... 

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... 

Water-soluble peptidocalix[4]arenes were synthesized by the introduction of arginine-rich narrow groove-binding residues at lower rims through solid-phase synthesis. The study of binding of these water-soluble bidentate ligands to well-matched and mismatched DNA duplexes by fluorescent titrations, ethidium bromide (EB) displacement assays, DNA-melting experiments, and circular dichroism (CD) analysis revealed a sequence-dependent groove-binding mechanism  

In this paper, the effect of different parameters of power plants, such as height above sea level, performance, ambient temperature, fuel type on emissions in Iran's power plants is investigated. Based on that, a general strategy for selecting the type of power plant, fuel that fit with the geographical situation in the Middle East is presented. Results taken from this scientific study shows that using natural gas to generate power in the region should be a priority. As well as expected, the value of various emission factors decrease by increasing power produce. Also the emission factors of combined cycle power plants are the lowest as compared to other types of power plants  

The effect of organosolv pretreatment on the structure of rice straw was analyzed under different treatment severities and solvent concentrations. At higher severities, on account of a greater fragmentation of less crystalline parts, including amorphous cellulose, hemicellulose, and lignin, the severer the pretreatment was, the higher the crystallinity index became; however, changes in the index was less tangible with a severity factor lower than 3.3. At the low to mild pretreatment temperatures (120 °C and 150 °C), higher ethanol concentrations led to the lower crystallinity index. Despite an increasing trend of crystallinity index at harsh conditions, SEM images indicated the formation of... 

The design procedure and measured results of a novel 4 × 4 Butler matrix are presented in this paper. This asymmetrical structure provides fairly flexible phase outputs; therefore, the array radiation pattern can be rotated around the array normal axis. The structure of this modified Butler matrix is discussed in detail, and the explicit design formulas are derived to achieve the arbitrary main beams direction. Using the proposed design procedure, the Butler matrix can provide even broadside and endfire beams. In addition, this structure is employed to design two Butler matrices, which generate similar patterns as a conventional 8 × 8 Butler matrix, using only single layer circuits with... 

This study aims to construct a quantitative framework to assess biological production of hydrogen from agricultural residues in a country or region. The presented model is able to determine proper crops for biohydrogen production, its possible applications and use as well as environmental aspects. A multiplicative decomposition method was designed to forecast future production and Monte Carlo simulation was employed in the model to evaluate the risk of estimations. From 2013 to 2050, the hydrogen production capacity could increase from 53.59 to 164.41 kilotonnes (kt) in Iran. The highest contribution to biohydrogen production (52.1% in 2013 and 73.3% in 2050) belongs to cereal crops... 

In this study, scaling effects on fiber metal laminates under tensile and three-point bending tests were investigated numerically and experimentally. The fiber metal laminate specimens were made of aluminum 1050 and unidirectional glass-epoxy. Two scaled sizes of specimens were prepared based on A1n, 0n=90n s. Some specified mechanical properties of these samples were investigated and results showed that fiber metal laminates obey scaling law under quasi-static loading. Explicit finite element code LS-DYNA was utilized for numerical simulation. After validating numerical simulation with experiments, scaling law was studied numerically for four different... 

This paper presents a decentralized adaptive control design for a class of large-scale nonlinear systems with unknown subsystems. When the subsystems are modeled by affine equations, a direct adaptive controller is devised based on the Lyapunov theory, so that the stability of the closed-loop system is guaranteed by introducing a suitably driven adaptive rule. A neuro-based structure is proposed when the subsystems are nonaffine, and the stability analysis is also performed based on the Lyapunov theory. Moreover, the unknown interactions among the subsystems are considered as having a nonlinear function against the simple form considered for the affine case. The proposed controllers are... 

Hybrid composites of MIL-101(Cr) and Nanoporous Graphene with ratios in the range of 10–50% were prepared via hydrothermal synthesis method. This study deals with an experimental investigation on selective oxidation of H2S into elemental sulfur in the range of 200–270 °C, the catalyst activity and selectivity toward sulfur was studied. High-temperature reactor tests indicated that the MIL-101(Cr)–NPG50–Mo could be a promising candidate with conversion and selectivity of 100% and 99.5% at 200 °C. The MIL-101(Cr)–NPG50–Mo stability showed there were not any significant changes in physical properties, the activity was evaluated after 20 h which was completely stable without any changes