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The quality of stable environments is crucial for maintaining the health of horses, minimizing air pollution, and potentially utilizing waste for fuel production. This study investigates the physical, chemical, and biological characteristics of dry horse bedding across twenty-four horse-riding clubs in Tehran. The objectives are to gather information on current stable practices and assess the suitability of used bedding for reuse or energy generation. Results revealed that the moisture content of the bedding ranged from 39.63% to 76.92%, leading to high drying costs. Ash content varied between 7.73% and 17.20%, while nitrogen content ranged from 0.78% to 1.77%. Hydrogen content was measured between 7.06% and 9.04%, with carbon content ranging from 14.74% to 24.46%. The particle size distribution showed that 70% to 94% of particles were smaller than 3.15 mm, with 0.5% to 1.5% below 0.075 mm, indicating potential health concerns. The average gross calorific value was 19.0372 MJ/kg. While the pellet samples did not meet specifications for non-industrial use, used horse bedding pellets exhibited greater suitability for industrial applications.
 

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Reducing consumption of fossil fuel, is a key effort to promote sustainable development. Transportation sector is one of the most important parts of fuel consumers. Urban form is one of the most important and effective factors in fuel consumption in transportation sector. Urban form includes some criterions such as density, mix land use and internal development of city. In order to reduce fuel consumption in transportation sector, urban form should be changed. This issue is more necessary due to increasing urban population and urban sprawl. Resident’s use of private car increases with distance from city center and lack of proper public transport system. This not only causes increasing of the fuel consumption, but also it increases emission of greenhouse gases, noise pollution and traffic congestion.  The present study has followed explanation of relationship between urban form and energy consumption in transportation sector. For this purpose, the theory of urban form, including compact city, transit-oriented development and Neo-traditional development and studies in other countries are surveyed and analyzed. Research findings indicate that socio-economic characteristics and physical variables and urban form are affected the usage of private car and fuel consumption in transportation sector. This study which is based on the findings of survey and analysis, seeks to develop a general conceptual framework for understanding the effective factors in Households Fuel Consumption in Transportation Sector.

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The use of genetic engineering tools to produce industrial strains, especially from non-model microorganisms such as cyanobacteria, is always subject to limitations. In this research, a system-oriented method was used to design a culture medium instead of strain designing and its ability to increase ethanol production by Synechocystis sp. PCC 6803 was experimentally evaluated. In this method, compounds are added to the medium to regulate the activity of target enzymes not for the purpose of being consumed by the cells, and thus, the designed culture medium eliminates the intracellular constraints on the production. A metabolic model was used to determine the minimum level of ethanol production and to identify genes that increase or decrease of their expression increase this minimum level. Then, regulators of the enzyme expressed by the target genes were extracted from the Brenda database and their effect on the production was evaluated experimentally and design of experiment was performed to optimize the concentration of the selected compounds. Among the compounds identified, two inhibitors (salicylic acid and mercuric chloride) and one activator (pyruvate) were selected to be added to the medium and their concentration was optimized using the central composite design method. The proposed regulatory medium increased the production of ethanol from 352 to 1116 mg/l, indicating the effectiveness of the added regulatory compounds on the cyanobacteria metabolism. The proposed system-oriented method can be used to design medium culture for other important bio-products such as recombinant proteins.

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In this paper, for control Voltage of two chamber Microbial fuel cell, two-type PI controller and MPC controller are used. For this purpose, two compartments of the model presented by Esfandyari  et al. [1, 2] have been used to model the microbial fuel cell. Then, based on this model, a classic PI controller based on the internal model and a MPC controller was designed and implemented. Based on the designed controllers, it was adjusted by adjusting the flow rate of the substrate to changes usually introduced in turbulence, such as the concentration of input to the substrate, or the effect of the uncertainty in the parameters of the process model, such as r_max and K_s. The results show that the MPC controller has a better performance compared to the classic PI controller.
 

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The production of bioethanol from lignocellulosic biomass could be considered as an appropriate and economic option to remove environmental disasters and improve energy security. In fact, lignocellulosic material is mainly composed of cellulose, hemicellulose and lignin. Lignin works as the adhering prevents the bioconversion of cellulose into sugars and ultimately to ethanol. To address the problem, various chemical, physical, physicochemical and biological methods have been suggested. Enjoying convenient operating conditions, production of non-hazardous wastes, and having no harmful side effects, make the biological methods a potentially proper option. Unfortunately, the biological methods are slower and less efficient in comparison with the other processes. In the present study, an attempt is made to resolve this problem in an enzymatic degradation of lignin of a rice straw sample. Several peroxidase enzymes were produced by a white rot fungus, and their effects on lignin removal from the biomass samples were investigated in shaking flasks. Lignin concentration and enzymes' activity were measured by the acetyl bromide-soluble lignin spectrophotometric method and optical density method using special reagents, respectively. The results revealed that the enzymatic treatment could remove at least 30% of the lignin content of the lignocellulosic biomass. To achieve the maximum activity of the enzymes, The chemical composition of the culturing medium was optimized for the concentration of important metal ions including Cu2+, Mn2+ and Zn2+ through Box Behnken response surface methodology. The enzymes' activity at the obtained optimal conditions increased four times for Manganese peroxidase, and lignin peroxidase.

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Laccase (benzenediol: oxygen oxidoreductase), is a multicopper polyphenol oxidase enzyme which has glycoprotein structure. The Researches are indicated that laccase enzyme can play role in detoxification of aromatic pollutants (as petroleum derivatives) and conversion them to less toxic compounds. On the other hand, because of its extensive, fibrous root system; Festuca arundinacea, creates an appropriate environment that causes increased catalysis of petroleum contaminants. Considering the fact that increasing in catalysis of pollutants can be provided by presence and changes in activity of various plant enzymes, in this research; the changes in laccase activity of Festuca's vegetative organs under soil pollution with different concentration of diesel fuel has been investigated. For this purpose, at first, the seeds of Festuca were cultivated in pots containing diesel fuel polluted soils and also control pots in greenhouse conditions. Then in specified time treatments, plants were harvested and plant extract containing laccase were extracted from aerial parts and roots of the plant, separately. After doing centrifuge, changes in enzyme activity were calculated by spectrophotometer. The results show that creation of soil pollution treatments compared with control samples, leads to increase in laccase activity in many cases. In other words, by increasing in laccase activity, the plant will increase its potency of decomposition and assimilation of pollutant hydrocarbons.

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Research subject: Iran is a country with high potentials for access to renewable energy sources such as solar, hydropower, wind, and biomass. Biodiesel is one of the renewable fuels that has always been proposed as a suitable and stable alternative (non-toxic, safe, and degradable) to fossil fuels.
Research approach: The experiences of different countries in the use of edible sources for biodiesel production shows that the use of edible sources has caused problems such as lack of food resources for human communities, lack of feed for livestock, and upsetting the balance in the food industry, and it can lead to a significant increase in the price of these resources. Therefore, many researchers have proposed the use of non-edible sources to address these problems. So far, very large non-edible sources for biodiesel production have been identified. In this paper, non-edible sources of biodiesel that are produced or have the potential to be produced in Iran are introduced and studied and a potential assessment study is presented for them.
Main results: In this work, the non-edible sources for biodiesel production are classified into four categories: agricultural waste, waste cooking oils, microalgae, and non-edible seeds. These sources are compared based on various parameters such as oil percentage, oil content per hectare, biodiesel production efficiency, viscosity, saponification number, and cultivation period, which according to the results, non-edible seeds, especially Nowruzak seeds, Castor, and safflower have been identified as the most rational and sustainable sources of biodiesel production in Iran. The present work also deals with the policies and incentives that the responsible institutions can apply for the prosperity of the biodiesel industry.

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In Iran, oil products are the most valuable export, 30% of which (Crude Oil) is used domestically every year. Countries like Iran depend heavily on oil revenues. One of the main sectors for consumption of crude oil in Iran is the transportation Industry. This paper aims to measure and estimate fuel productivity in land transportation in Iran using available data from 1973-2003. The function of fuel productivity is estimated using time series analysis, and the co-integration with stationary variables have been accounted and analyzed. At this stage, initially the co-integration variables of the model are known, and then, the structure of the model and the number of optimal orders are identified. The next step however, determines the number of co-integration vectors of the model which eventually with some restrictions estimate the fuel productivity function within the land transportation sectors e.g. rail and road.

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Ethanol as a renewable biofule is an appropriate and viable alternative to the challenging fossil fuels. Bacillus subtilis, a gram positive bacterium, seems to be a promising choice since it has many useful features. For example B.subtilis ferments broad range of sugars derived from lignocellulosic hydrolysis. Transformation of this cellulytic bacterium to an ethanologenic one was accomplished via metabolic engineering techniques and Ethanol production operon of Z.mobilis was introduced to the B.subtilis. SR1 and SR21 strains expressed plasmid-borne ethanologenic genes of Z.mobilis but the genes had been integrated into the SR22 genomic DNA. Also lactate dehydrogenase gene had been knocked-out in SR21 and SR22 strains. Defect of cell growth in SR21 and SR22, suggests that NAD+ oxidation by lactate dehydrogenase is important for anaerobic growth. Considering the impact of Fe2+ ion on alcohol dehydrogenase II activity, in further experiments Fe2+ was added to the culture media and improvement in growth rates was seen. Final yield of ethanol production of SR1, SR21, and SR22 strains were 53.8%, 86.7%, and 83.9% respectively.

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In this research, biodiesel was initially produced from waste vegetable oil by transesterification reaction. The main properties of this fuel were compared with the ASTM D-6751 standard.then, performance of MF-399 tractor engine was tested and evaluated by using 5 to 25 percent biodiesel and diesel blends. Test results showed that, the power and torque of MF-399 tractor engine were increased, using biodiesel and diesel blends. This is because of good combustion of biodiesel due to high oxygen content of this fuel. There was also a slight increase in the fuel consumption and specific fuel consumption of biodiesel and diesel blends due to low calorific value of biodiesel. Results show that the B5D95 blend has the best performance and the lowest increase in specific fuel consumption among the other blends. The fuel consumption and specific fuel consumption of B25D75 was lower than the B20D80 blend. Therefore, if the goal is using high amount of biodiesel, B25D75 blend is recommended for use in MF-399 tractor engine.

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Biofuels are the main substitute to fossil fuels. These fuels are less polluting in compari-son to fossil fuels and can be produced from agricultural material residues for use in die-sel engines. In this research work bioethanol was produced from potato waste. It was de-hydrated in a vapor phase using 3A zeolite and was used in combination with sunflower methyl ester oil and diesel fuel blending which was evaluated thereafter. The sunflower methyl ester was also produced using a transesterification method. Considering the labo-ratory conditions and fuel stability limits to be used, the suitable blending proportion of bioethanol and diesel fuel was determined to be 12 to 88 and then, for maintaining fuel stability at temperatures lower than 15oC, the sunflower methyl ester was added to the mixture. The pour point of the fuel and different fuel blends, the viscosity, cetane number, flash point, amount of fuel ash, sulfur content and copper corrosion were determined in the laboratory. Experiments show that ethanol plays an important role on the flash point of the blends. With the addition of 3% bioethanol to diesel and sunflower methyl ester, the flash point was reduced to 16oC. The viscosity of the blends was reduced with the in-crease in the amount of ethanol. The sulfur content of bioethanol and sunflower methyl ester is very low compared with that of diesel fuel. The sulfur content of diesel is 500 ppm whereas that for ethanol and sunflower methyl ester is 0 and 15 ppm, respectively. The lower amount of sulfur content facilitates the use of fuel blends in diesel engines. For the ethanol and sunflower methyl ester combination, this amount is less than 20 ppm.

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In this research work, a comprehensive combustion analysis has been conducted to evaluate the performance of a low speed diesel engine (M8/1 Lister) using biodiesel fuel. Waste vegetable cooking oil as an alternative fuel. Biodiesel obtained from waste vegetable cooking oil (WCO) as an alternative fuel. The properties of biodiesel produced from WCO was measured based on ASTM standards. In order to compare brake power, torques , brake specific fuel consumption (BSFC) and concentration of the UHC and CO emissions of the engine, it has been tested under same load of Dynamometer(5 levels) and biodiesel fuel blends (levels)) at constant engine speed(750 rpm). The results were found to be very comparable. An artificial neural network (ANN) was developed based on the collected data of this work. Multi layer perceptron network (MLP) was used for nonlinear mapping between the input and the output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted values. The results showed that the training algorithm of Back Propagation was sufficient in predicting the engine torque, brake power, specific fuel consumption and exhaust gas components for different engine loads and different fuel blends ratios.

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There is a full connection between the electrochemical quantities of a fuel cell and the curves of the temperature and primary materials at the catalyst region. These quantities are strongly linked to the mass and heat transfer phenomena in the other regions. In the present paper, the lattice-Bolzmann method, as a microscale model with good computational capabilities in the problems such as the fuel cell, has been utilized to simulate the fluids flow and heat transfer in a two-dimensional cross section of a proton exchange membrane fuel cell including the channel, bipolar plate, gas diffusion layer and catalyst of the cathode and the electrochemical characteristics in the catalyst layer have been analyzed. By representing a method for estimation of the changes in the concentration along the channel, the serpentine arrangement has been modeled. The results reveal the essential role of the bipolar plate on the quantities at the catalyst layer.

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     One of the main inputs in manufacturing sector of Iran is fossil fuels with prices much lower than prices elsewhere in the world which are offered to producers and consumers. This accounts for a large share of subsidy payments allocated to different sectors of economy. The effect of subsidies on energy costs and prices of goods and services incur complex changes on the economy through allocation of resources. In this paper, using the computational general equilibrium model, effects of removal of fuel subsidies on production changes, cost and price in the Khorasan Razavi province has been studied. The results show that the elimination of subsidy on fossil fuels increased production, cost and price Indices. The highest growth rate of production and cost indices is in the gas sector and the highest growth rate of price index is in the oil sector.  

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Thermal power plants consume near to 50 billion cubic meters of natural gas each year. So, optimization of power plants in terms of fuel consumption has become an important issue because of economic values and environmental effects. More than 50 percent of electricity is produced by CCGT and SCGT. In addition, CCGT efficiency is much higher than that of SCGT. So, in this paper these technologies are compared. The outcomes show benefits over costs ratio is affected by fuel price and utilization time. In subsidy prices (before energy price reform), B/C ratio of this substitution is less than one. If fuel price increases more than 500 Rials per cubic meter, using CCGT is more economical than SCGT for mid load power plants. If fuel prices are more than 1300 Rials per cubic meter, B/C ratio will be greater than one in any utilization time.  But this ratio is not greater than one for all cases. If all SCCTs are substituted with CCGTs, yearly natural gas consumption will reduce near to 3.5 billion cubic meters. These are 7% and 2.5% of yearly fuel consumption in power plants and total yearly natural gas consumption respectively. 

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In this study, the geometrical changes at cathode electrode in proton exchange membrane (PEM) fuel cell has been considered by inserting baffle plates across the channel. The effects of the blockage with various gap ratios, shape, thickness and numbers of the baffle plates, and the porosity of the diffusion layer on the oxygen transport and the pressure drop across the channel length are explored. It is revealed that partially blocked oxygen channel with rectangular baffle has the most velocity and oxygen concentration in the gas diffusion layer/catalyst layer interface than that of the other shape of plates; however results in a penalty of high pressure-loss. Increasing the porosity of gas diffusion layer (GDL), baffle plate thickness and baffle number and/or reducing the gap size in order to enhance the reactant gas transport result in pressure loss. Here, among the parameters considered, the porosity of GDL, gap ratio and plate number have the most remarkable impact on the oxygen transport to GDL and variation in pressure drop.

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In this paper, an algorithm is presented based on using bspline function for optimizing tank cross section. This process minimizes fluid c.g. height and overturning moment and improve rollover threshold of tank vehicles. This algorithm receives tank capacity specifications as inputs and offers fourth order bspline function with 10 control points that has more roll stability, and then optimizes it for different filling conditions. This algorithm is based on the third order bspline function with 8 control points, initially. Therefore, with averaging and optimizing, range of control points is modified and the numbers of control points and degree of bspline function are increased. The results show that, the mutation rate is better to be between 4 and 6%, and the number of individuals in each generation should be at least 40. The algorithm presented in this paper, is a fast and accurate method for optimization of tank cross section in different filling conditions. The Algorithm based on GA maintains simplicity applicable for industries and specially has a rollover threshold of 10% higher than conventional tanks.

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Fuel control unit (FCU) is one of the most essential parts in a gas turbine engine; therefore it is necessary to be studied as an important part of the fuel control system. This paper report the use of Nonlinear Auto Regressive with eXogenous input (NARX) neural network model for modeling of the jet engine FCU. Therefore, To measure and recording data from the FCU inputs and output, the test bench including hydraulic system, data acquisition system and induction motor control system are designed and constructed. This setup is a mechatronic collection which includes mechanical design, discharge and pressure sensors, tachometer, control unit and piping systems. The process of modeling is carried out in MATLAB software. The identified model is evaluated with validation data and its response is compared with the real system response. Results demonstrate the effectiveness of the NARX neural network model and show that the real system is estimated by the NARX neural network model accurately.

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In this study, convergent nozzle ejector in the PEM fuel cell system is analyzed. This method can reduce the parasitic power of the fuel cell, recycle the unconsumed hydrogen to the fuel cell to increase the fuel usage efficiency, utilize the pressure potential energy of hydrogen and regulate the anode humidity with the recycle gas. For this purpose, continuity, momentum, energy and state equations are solved by numerical methods and effects of pressure drop (through the channel towards the anode), operating pressure and temperature of the fuel cell and also nozzle diameter on the ejector performance was analyzed. With decreasing of pressure drop, even in primary lower pressure, increasing of performance pressure the performance of ejector will improved. The temperature increase has no effect on the performance of the ejector itself, but has enormous effect on the fuel cell. Increasing the diameter ratio of the constant diameter zone to the nozzle diameter leads to increasing of recirculation anode line of the fuel in higher pressure.