Journal of Agricultural Machinery

Abstract This research aims to optimize the mixing process in gas-lift anaerobic digesters of municipal sewage sludge since mixing and maintaining uniform contact between methanogenic bacteria and nutrients is essential. Wastewater municipal sludge sampling was performed at the Ahvaz West treatment plant (Chonibeh, Iran) during the summer of 2022. A Computational Fluid Dynamics (CFD) model was implemented to simulate, optimize, and confirm the simulation process using ANSYS Fluent software 19.0. The velocity of the inlet-gas into the digester was determined and a draft tube and a conical hanging baffle were added to the digester design. Different inlet-gas velocities were investigated to optimize the mixing in the digester. Furthermore, turbulence kinetic energy and other evaluation indexes related to the sludge particles such as their velocity, velocity gradient, and eddy viscosity were studied. The optimal inlet-gas velocity was determined to be 0.3 ms^-1. The simulation results were validated using the Particle Image Velocimetry (PIV) method and the correlation between CFD and PIV contours was statistically sufficient (98.8% at the bottom corner of the digester’s wall). The results showed that the model used for simulating, optimizing, and verifying the simulation process is valid. It can be recommended for gas-lift anaerobic digesters with the following specifications: cylindrical tank with a height-to-diameter ratio of 1.5, draft tube-to-digester diameter ratio of 0.2, draft tube-to-fluid height ratio of 0.75, the conical hanging baffle distance from the fluid level equal to 0.125 of the fluid height, and its outer diameter-to-digester diameter of 2/3.

Abstract Introduction
The world’s growing population has led to an inevitable increase in energy demand, and this, in addition to the depletion of non-renewable energy sources, can lead to several environmental issues. Wind power has proven to be a reliable and sustainable source of electricity, particularly in light of the pressing need to mitigate environmental impact and promote the use of renewable energy. The purpose of this research is to investigate and compare the environmental effects of electricity production from two wind power plants, Aqkand and Kahak, using wind turbines with a capacity of 2.5 megawatts for a period of three different lifetimes (20, 25, and 30 years).
Materials and Methods
The present study investigates the environmental effects of electricity generation during the life cycle of wind farms (Kahak and Aqkand) during the construction and operation of these power plants and the cumulative exergy demand index. The specifications of the wind turbines used in the current research are: turbine capacity of 2.5 MW, rotor diameter of 103 meters, rotor weight of 56 tonnes, three blades, each blade is 50.3 meters long and weighs 34.8 tonnes. The turbines are manufactured by Mapna and used in dry conditions. A functional unit of one kilowatt of electricity was selected and the data were analyzed in SIMAPRO software using IMPACT2002+ method with 15 midpoint indicators and four final indicators.
Results and Discussion
The results showed that the stage of raw materials and production has the highest impact on the creation of midpoint indicators, which is due to extraction, manufacturing, and production of parts such as steel casting using non-renewable energy and activities such as high-temperature welding. The total environmental index of Aqkand and Kahak wind power plants for 1 kWh of generated electricity was 5.84 and 4.45 μPt respectively, more than half of which belongs to the damage to human health category. The investigation of the ionizing radiation index showed that the use of diesel fuel in the installation phase resulted in the highest amount of emissions in both of the power plants, so the share of pollutant emissions in the raw materials and production phase is more than 40%, and in the installation phase due to diesel fuel consumption was more than 48%. The investigation of the eutrophication index showed that the raw materials and production stage accounted for more than 95% of the damage to the ecosystem quality category, and in the meantime, copper and electrical components had the highest amount of contribution to the raw materials and production stage. Additionally, diesel fuel accounted for the largest part of the result in the installation stage, and the transportation and maintenance stage included less than 1% of this result. The investigation of the renewable energy consumption index showed that the stage of raw materials and turbine production in the Aqkand power plant with a share of 68% and the Kahak power plant with a share of 70% had the greatest effect on the category of resource damage. Also, the installation and commissioning phase was the second most effective factor in the category of resource damage due to the use of diesel fuel. The study of the cumulative exergy demand index showed that non-renewable-fossil resources had the largest share in exergy demand (0.15 MJ) to produce one kilowatt of electricity generated from power plants.
Conclusion
In this study, the results showed that in both plants, about 70% of various respiratory effects, 60% of human health issues, and 25% of acidification and global warming are caused in the raw materials and manufacturing phase. Furthermore, the installation phase is responsible for 17% and 16% of climate change in the Aqkand and Kahak power plants respectively, and between 14% and 26% of other environmental factors.

Abstract Introduction
Anaerobic bacteria break down organic materials like animal manure, household trash, plant wastes, and sewage sludge during the anaerobic digestion process of biological materials and produce biogas. One of the main issues in using biogas is hydrogen sulfide (H₂S), which can corrode pipelines and engines in concentrations between 50 and 10,000 ppm. One method for removing H₂S from biogas with minimal investment and operation costs is biofiltration. Whether organic or inorganic, the biofilter's bed filling materials must adhere to certain standards including high contact surface area, high permeability, and high absorption. In this study, biochar and compost were used as bed particles in the biofilter to study the removal of H₂S from the biogas flow in the lab. Afterward, kinetic modeling was used to describe the removal process numerically.
Material and Methods
To remove H₂S from the biogas, a lab-sized biofilter was constructed. Biochar and compost were employed separately as the material for the biofilter bed. Because of its high absorption capacity and porosity, biochar is a good choice for substrate and packed beds in biofilters. The biochar pieces used were broken into 10 mm long cylindrical pieces with a diameter of 5 mm. Compost was used as substrate particles because it contains nutrients for microorganisms. Compost granules with an average length of 7.5 mm and 3 mm in diameter were used in this study. For the biofilter reactor, each of these substrates was put inside a cylinder with a diameter of 6 cm and a height of 60 cm. The biofilter's bottom is where the biogas enters, and its top is where it exits. During the experiment, biogas flowed at a rate of 72 liters per hour. Mathematical modeling was used to conduct kinetic studies of the process to better comprehend and generalize the results. This method involves feeding the biofilter column with biogas that contains H₂S while the biofilm is present on the surface of the biofilter bed particles. The bacteria in the biofilm change the gaseous H₂S into the harmless substance sulfur and store it in their cells. The assumptions that form the foundation of the mathematical models are: the H₂S concentration is uniform throughout the gas flow, the gas flow is constant, and the column's temperature is constant at a specific height.
Results and Discussion
In the beginning, biochar was used as a substrate in the biofilter to test its effectiveness, and the results obtained for removing H₂S from the biogas were acceptable. H₂S concentration in biogas was significantly reduced using biochar beds. It dropped from 300 ppm and 200 ppm to 50 ppm where the greatest H₂S concentration reduction was achieved. The level of Methane in the biogas was not significantly impacted by the biofilter. This is regarded as a significant outcome when taking into account the goal which is producing biogas with a high concentration of methane. The H₂S elimination effectiveness was 94% with the biochar bed and biogas input with 185 ppm H₂S concentration. The removal efficiency reached 76% with the compost bed and input concentration of 70 ppm. Using mathematical models, the simulation was carried out by modifying the model's parameters until the predicted results closely matched the experimental data. It may be concluded that the suggested mathematical model is sufficient for the quantitative description of H₂S removal from biogas utilizing biofilm in light of how closely the calculation results matched the experimental data. The only model parameter that was changed to make the model results almost identical to the experimental data was the value of the maximum specific growth rate (μ_max) which has the greatest influence on the model results. The value of μ_max for the biochar bed was calculated as 0.0000650 s^-1 and for the compost bed at 70 ppm and 35 ppm concentrations as 0.0000071 s^-1 and 0.0000035 s^-1, respectively.
Conclusion
The primary objective of this study is to examine the removal of H₂S from biogas using readily available and natural substrates. According to the findings, at a height of 60 cm, H₂S concentration in biochar and compost beds decreased from 185 ppm to 11 ppm (removal efficiency: 94%) and from 70 ppm to 17 ppm (removal efficiency: 76%), respectively. The mathematical models that were created can quantify the H₂S elimination process, and the μ_max values in biochar and compost were calculated as 0.0000650 s^-1 and 0.0000052 s^-1, respectively.
Acknowledgment
The authors would also like to thank UNESCO for providing some of the instruments used in this study under grant number No. 18-419 RG, funded by the World Academy of Sciences (TWAS).

Abstract This study presents the effects of compressed natural gas fuel on a four-cylinder compression ignition engine. Compressed natural gas as the main fuel and diesel fuel as the igniter were used to investigate performance and emissions from the dual fuel engine. According to the engine speed and load, the amount of diesel fuel as igniter was adjusted using mechanical changes in the governor, while no ignition system was used. The engine experimental tests were performed at engine speeds of 1200, 1400, 1600, 1800 and 2000 rpm, using diesel fuel and dual fuel. These data were collected in the Engine Research Center of Tabriz Motorsazan Company and experimental runs were repeated three times. The maximum torque of the engine in diesel mode was 360 N m at 1400 rpm. Compared to the diesel mode, the dual fuel mode showed the maximum torque by 334 N m at 1600 rpm, which is about 26 N m less than that gained from the diesel mode. Considering emissions analysis at 2000 rpm, it is seen that the amount of NOX, HC, CO₂ and CO emissions in the dual fuel mode was 20, 53, 16 and 86% more than diesel mode, respectively. However, O₂ and soot showed the highest reduction at 2000 rpm for dual fuel mode by 51% and 69% respectively. This study indicated that there was a considerable enhancement in exhausted emissions when the injection of the diesel fuel as igniter was done mechanically. In this regard, control the amount and time of the igniter injection could likely be helped for better control of emissions. Therefore, further research on the modification of the diesel injection system as igniter or CNG injection system is needed towards reducing emissions.

Abstract Introduction
Providing new solutions to control wet waste is one of the most important issues in maintaining public health. Drying will reduce the harmful effects on the environment by reducing moisture and the smell of wastes as well as easy transportation and disposal costs. The purpose of the design and development of the household dryer is to dry food waste in order to reduce its volume and prevent the spread of its pollution in the air, water, and soil. To study the drying behavior of food waste, an experimental cabinet dryer was designed, fabricated, and evaluated for drying food waste.
Materials and Methods
The dryer consisted mainly of the drying chamber, electric heater, fan, air inlet channel, mesh tray, air distribution plates, temperature sensor, and control panel. Different parts of the dryer were made of a stainless galvanized sheet. The dryer was modeled using Catia 2019 software and its various parts were designed. The heating power was calculated as 2.7 kW. A centrifugal fan with an air volume of 310 m³h^-1, 2800 rpm, and 110 Pa was used to supply airflow in the dryer. In the drying process, a tray with medium and lateral air passage was fabricated and applied. Food waste was obtained from fruit and vegetable waste, homemade food, and fruit shops. And nonfood items such as glass, paper, plastics, and metals were separated from the waste and crushed with a shredder, and reduced to sizes less than 20 mm. First, the product was placed in the environment for one hour and then pressed with a mechanical press with the same pressure to eliminate part of the water. An anemometer UT363 model made in China was used to measure the air velocity. The temperature was measured and controlled by a temperature thermostat of G-sense model made in Iran. The effect of three temperatures of 50, 60, and 70 ^°C and three inlet velocities of 1, 1.5, and 2 m s^-1 on the kinetics and intensity of drying of food waste and energy consumption of food waste with a thickness of 3 cm was investigated. Moisture ratio and drying intensity diagrams were extracted. Diffusion, activation energy, and energy consumption were determined.
Results and Discussion
Drying kinetics diagrams showed that temperature had a significant effect on moisture variation of food waste during drying. Drying period decreased with increasing temperature. The slope of the drying intensity diagrams increased with the increase of the dryer temperature. Drying rate was decreased at the temperature of 70 °c and it had a steeper slope that indicates the more intensity of the drying process in this condition. The drying process of all three samples occurred in the falling rate stage. The air duct on the side and in the middle of the tray caused hot air conducted above the tray and increased energy consumption. Effective moisture diffusivity of food waste during the drying process was in the range of 3.65×10^-9-4.56×10^-9 (m² s^-1). The effective moisture diffusivity at temperatures of 50 ^°C and 60 ^°C was less than 70 ^°C. Because at the temperature of 70 ^°C, the membrane resistance of the cell destroyed by high heat and increased the diffusion coefficient in the material.
Conclusion
Increasing temperature caused the drying period decreased and the drying occurred in the falling rate stage. Temperature and the interaction of velocity and temperature had a significant effect on the drying process. The highest drying intensity and the lowest drying time were observed at the temperature of 70 ^°C and a velocity of
2 m s^-1. Energy consumption had the maximum value at the temperature of 70 ^°C and a velocity of 2 m s^-1 and a minimum value at the temperature of 50 ^°C and a velocity of 1 ms^-1. The amount of activation energy for the food waste mass at three velocities was equal to 10417.44 J mol^-1.

Abstract Introduction
Increasing industrialization, growing energy demand, limited reserves of fossil fuels, and increasing environmental pollution have jointly necessitated for exploration of a substitute for conventional liquid fuels. Vegetable oils can be used as alternatives to petroleum fuels for engine operation. These oils are mixtures of free-fatty acid molecules to contain carbon, hydrogen, and oxygen atoms. The ability to simulate the process of converting chemical energy to heat, energy users of computational fluid dynamics software in the design, analysis, and optimization of high-tech tools. Also, simulation saves time and reduces costs, workforce, and the space required.
Materials and Methods
In this research, a one-dimensional computational fluid dynamics solution with GT-Power software was used to simulate a four-cylinder, four-stroke, direct injection diesel engine to study the performance and exhaust emissions characteristics with different speeds and blends at full load. The engine speeds were chosen to be 1100 to 1400 rpm at an interval of 100 rpm. Also, fuel blends such as diesel (as a base), B5, and B10 biodiesel were selected for engine testing. To model a engine, we should have the dimensions of the engine, input air collection, output gases collection, the amount of sprinkled fuel, valves properties, combustion, and some of the estimates corresponding to the cylinder’s thermodynamic parameters when opening the output and input gate and to exchange the heat inside the cylinder as the input data. The model mainly consisted of an air cleaner, intake valve, exhaust valve, intake and exhaust port, injection nozzle, engine cylinder, and engine. Engine cylinder’s intake and exhaust ports are modeled geometrically with pipes. Before this investigation was carried out, a validation model for evaluation was done by experimental and simulation data. The validation results showed that the software model error is acceptable.
Results and Discussion
The engine performance and emissions were evaluated in terms of engine torque, specific fuel consumption, NOx, and CO emission at different engine speeds and fuels at full load. The results showed that with increasing the engine speeds, torque increased. On the other hand, the maximum engine torque for the diesel engine is slightly lower than the biodiesel-blended that increased by 4.4% because of the higher density and viscosity of biodiesel than diesel. Specific Fuel Consumption (SFC) is a measure of the fuel efficiency of any prime mover that burns fuel and produces rotation, or shaft, power. The results indicated that by increasing engine speeds, the SFC increased. A fuel with a lower heating value should be injected with more mass into the engine. This will increase the SFC. So, the maximum engine SFC for the diesel engine is more than the biodiesel-blended that decreased by 4.45% because of better fuel combustion and more power generation of biodiesel than diesel. The only nitrogen oxide that can be formed in an engine combustion temperature is nitrogen monoxide (NO). This pollutant factor can be converted to nitrogen dioxide (NO2) over the time of exhaust gas. The results showed that with increasing the engine speeds, the NOX emissions decrease steadily and then increases, which is due to the high temperature in the cylinder. The viscosity and density of fuels have an effect on NOX emission, and because of the larger droplets of the fuel, it released NOX. The highest NOx emissions belong B10 biodiesel in 1400 rpm, due to the high oxygen content of this fuel and the lowest NOx emissions belong B10 biodiesel in 1300 rpm, due to the low density of the fuel compared to diesel. CO is a colorless and odorless gas, whose even very low concentrations are dangerous for humans and animals. The results showed that with increasing the engine speeds, the CO emission decreased and the minimum CO emission for diesel engine is more than the biodiesel-blended that decreased by 37.61% because of excess oxygen availability and complete combustion in biodiesel than diesel.
Conclusion
The results of this study showed that the B10 blend in high engine speeds, generally had the best performance and emissions characteristics among the three fuels used in this study. Also, this investigation will assist in the development of WCO biodiesel as a viable sustainable fuel source through the use of a CFD model, optimized engine configuration, and technical report.

Abstract Introduction
Wheat, is the most important crop in the world. In Iran, wheat is the most important and strategic agricultural crop, due to its vital role in providing food and feeding livestock. Because wheat harvesting operation has a significant share of total grain losses, it is considered as the most important and sensitive stage of production. Recently, in Iran, the need for straw to feed livestock has increased sharply, and since wheat is the main source of straw production, changes have been made in the configuration of the grain combine harvester so that in addition to collecting grain, it can crush and collect straw. These combine harvesters are known as straw collecting combine harvesters. The growing need for straw, along with the high cost and difficulty of straw collecting, has made straw collecting combine harvesters more popular, especially in areas where animal husbandry is common alongside agriculture. Despite facilitating and increasing the possibility of straw collection by this type of combine harvesters, in many cases grain losses have increased. Therefore, it is necessary to investigate the amount of grain losses in this type of combine harvester and determine the factors affecting its losses.
Materials and Methods
This study was conducted to investigate the effect of ground speed and wheat yield on grain loss in a straw collecting combine harvester. The use of this type of harvester was also analyzed economically. Two models of JD-1055 and JD-1165 combine harvesters were considered for evaluation. The experiments were performed in a split factorial design in the form of a randomized complete block design. Grain yield (at three yield levels: less than 2 Ton ha^-1, 2 to 5 Ton ha^-1, and more than 5 Ton ha^-1) was the main factor and the other two treatments, the model of combine harvester and the ground speed (with three levels: 1, 1.5 and 3 km h^-1) were factorially placed in subplots. Loss components including head loss, combine harvester body loss, end loss, threshing unit loss, cleaning unit loss, and quality losses were measured and compared with that of a conventional grain combine harvester. Field capacity and harvesting cost were also measured for both types of combine harvesters. Finally, based on cost-benefit analysis, the straw collecting combine harvester was compared with the conventional combine harvester economically.
Results and Discussion
The results showed that in addition to the main effects, the two-way and three-way interactions were also significant for the studied factors on head loss, body loss, end loss, threshing unit loss, cleaning unit loss, and quality losses of straw collecting combine harvester. The losses of the straw collecting combine harvester are strongly affected by the ground speed and the grain yield. The percentage of grain loss in low yields (less than 2 Ton ha^-1) was significantly higher than that of medium (2 to 5 Ton ha^-1) and high yields (more than 5 Ton ha^-1). The average loss of JD-1055 was less than JD-1165, mainly because of more loss in threshing and cleaning units. The highest total losses, with a rate of 10.54%, were related to JD-1165 in low yields, while the lowest percentage of total losses, at a rate of 2.54%, was related to JD-1055 in medium grain yield and low speed
(1 km h^-1). The total grain losses of conventional combine harvesters obtained about 3.22% while the total grain losses of straw collecting combine harvesters were approximately 5.44%. In general, the losses of straw collecting combine harvester were about 2.22% more than that of the conventional combine harvester. The economic evaluation showed that in the region where animal farming is common along with agriculture, the use of straw collecting combine harvester is more economical than a conventional combine harvester.
Conclusion
Combine harvester model, grain yield, as well as ground speed of the combine harvester affects the grain losses in different units of a straw collecting combine harvester as well as total losses. As the grain yield and the feed rate increase, the total losses of this combine decrease at first but increase again in high yields. Adjusting the feed rate helps reduce the end losses and total losses of straw collecting combine harvester. In the study area, using a straw collecting combine harvester is more economical than a conventional combine harvester.

Abstract Introduction
Since anaerobic digestion leads to the recovery of energy and nutrients from waste, it is considered the most sustainable method for treating the organic fraction of municipal solid wastes.
However, due to the long solid retention time in the anaerobic digestion process, the low performance of the process in biogas production as well as the uncertainty related to the safety of digested materials for utilizing in agriculture, applying different pretreatments is recommended.
Thermal pretreatment is one of the most common pretreatment methods and has been used successfully on an industrial scale. Very little research, nevertheless, has been done on the effects of different temperatures and durations of thermal pretreatment on the enhancement of anaerobic digestion of the organic fraction of municipal solid wastes (OFMSW). 
The main effect of thermal pretreatment is the rapturing cell membrane and dissolving organic components. Thermal pretreatment at temperatures above 170 ^°C may result in the formation of chemical bonds that lead to particle agglomeration and can cause the loss of volatile organic components and thus reduce the potential for methane production from highly biodegradable organic waste. Therefore, since thermal pretreatment at temperatures above 100 ^°C and high pressure requires more energy and more sophisticated equipment, thermal pretreatment of organic materials at low temperatures has recently attracted more attention. According to the researchers, thermal pretreatment at temperatures below 100 ^°C did not lead to the decomposition of complex molecules but the destruction of large molecule clots.
The main purpose of this study was to find the optimal levels of pretreatment temperature and time and the most appropriate concentration of digestible materials to achieve maximum biogas production using a combination of the Box Behnken Response Surface Method to find the objective function followed by optimizing these variables by Genetic Algorithm.
Materials and Methods
In this study, the synthetic organic fraction of municipal solid waste was prepared similar to the organic waste composition of Karaj compost plant. The digestate from the anaerobic digester available in the Material and Energy Research Institute was used as an inoculum for the digestion process. Some characteristics of the raw materials that are effective in anaerobic digestion including the moisture content, total solids, volatile solids of organic waste, and the inoculum were measured. Experimental digesters were set up according to the model used by MC Leod. After size reduction and homogenization, the synthetic organic wastes were subjected to thermal pretreatment (70, 90, 110 ^°C) at specific times (30, 90, 150 min).
The Response Surface methodology has been used in the design of experiments and process optimization. In this study, three operational parameters including pretreatment temperature, pretreatment time, and concentration of organic material (8, 12, and 16%) were analyzed. After extracting the model for biogas efficiency based on the relevant variables, the levels of these variables that maximize biogas production were determined using a Genetic Algorithm.
Results and Discussion
The Reduced Quadratic model, was used to predict the amount of biogas production. The value of the correlation coefficient between the two sets of real and predicted data was more than 0.95. The results suggested that pretreatment time followed by the pretreatment temperature had the greatest contribution (50.86% and 44.81%, respectively) to biogas production. Changes in the organic matter concentration, on the other hand, did not have a significant effect (p ˂ 0.01) on digestion enhancement (1.63%) but were statistically significant at p ˂ 0.10.
The response surface diagram showed that the increase in pretreatment time first led to a rise and then a fall in biogas production. The decline in biogas production seemed set to continue with pretreatment time. Meanwhile, the increase in pretreatment temperature from 70 ^°C to 110 ^°C first contributed to higher biogas production and then the decrease in gas production occurred.  
The reason for this fall was probably the browning and Maillard reaction.
The regression model was applied as the objective function for variables optimization using the Genetic Algorithm method. Based on the results of this algorithm, the optimal thermal pretreatment for biogas production was determined at 95 ^°C for 104 minutes and at the concentration of 12%. The expected amount of biogas production by applying the optimal pretreatment conditions was 445 mL-g^-1 VS.
Conclusion
In this study, the variables including thermal treatment temperature and time as well as the concentration of organic waste to be anaerobically digested were optimized to achieve the highest biogas production from anaerobic digestion.
Statistical analysis of the results revealed that the application of thermal pretreatment increased biogas production considerably. According to the regression model, the contribution of pretreatment time and temperature to biogas production was significant (50.86% and 44.81% respectively). In stark contrast, varying substrate concentrations in the range of 8 to 16% had a smaller effect (1.63%) on biogas production. The results of this study also showed that the best pretreatment temperature and time were 95 ^°C and 104 minutes, respectively, at a concentration of 12% by generating 445 mL-g^-1 VS biogas which is 31.17% higher than the biogas yield from anaerobic digestion of untreated organic wastes at this concentration.

Abstract Introduction
So far, many studies have been conducted to evaluate the impact of input consumption patterns on energy, economic, and environmental indicators on horticultural and greenhouse crops in Iran. A review of these studies shows that the causes of the current situation in the systems have not been investigated. These studies are mostly reporting the current situation and the interventions and their effect on improving the input consumption pattern in the sustainability of the system have not been considered by researchers. Also, studies showed that the study location and products do not fit well with the volume of production in the horticultural and greenhouse sector of Iran. Therefore, in order to increase the effectiveness and future direction of studies in this field, this review study was conducted. In this article, Iranian horticultural and greenhouse production systems were reviewed and analyzed by reviewing the published articles between 2008 and 2018, using the PRISMA method. The PRISMA method is a well-known method for conducting systematic review studies. The PRISMA method includes the following sections: background; objectives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions, and implications of key findings. In this article, 16 types of garden products and 6 types of greenhouse products were studied.
Material and Methods
In this study, the methods used to determine the status of energy consumption, economic and environmental patterns for horticultural and greenhouse crops were analyzed. For this purpose, the indicators of total energy consumption (TEI), energy efficiency (EUE), net energy (NE), and energy efficiency (EP) were examined in the section of energy. The issue of sensitivity analysis of energy inputs was also examined and the highest values of t-statistic and MPP were reported for products. In some articles, the data envelopment analysis method was used in systems performance analysis. The indicators used included technical efficiency (TE), pure technical efficiency (PTE), scale efficiency (SE), and energy-saving target ratio (ESTR). The results of them were summarized and reported. In some studies, the method of artificial neural networks and the Adaptive Neuro-Fuzzy Inference System were used. In general, in the present article, the challenges and risks in the methods used in previous studies were considered. The issue of sampling in the analysis of agricultural systems was discussed in detail and a new sampling procedure was proposed. To draw a general picture of energy and environmental indicators of orchard and greenhouse systems in Iran, the results published in the articles were reviewed. Not all researchers use the same equivalents in calculating the indices, and this makes the results of the studies slightly different from each other. The existence of such differences causes some deviations in comparing the results of similar articles in the same products. However, to adjust for these differences, averaging was used in the index report.
Results and Discussion
The study of the share of inputs in the total energy consumption shows that for horticultural products, the share of fertilizer and electricity inputs is very significant. In the case of greenhouse products, fuel input, which is mainly diesel, has the largest share of energy consumption. Walnuts have the lowest energy consumption and strawberries have the highest energy consumption among orchard products. Grapes, apples, and walnuts also have positive net energy, so they have the highest energy efficiency compared to other products. The most important inputs that have the greatest potential for energy savings in most products are diesel fuel and electricity. Among greenhouse crops in cucumber production, diesel fuel has great potential for energy savings that need to be reduced in future research. In the case of strawberry and rose products, electricity input has the greatest potential for energy savings. Knowing the potential of inputs that can be saved can be effective in changing the behavior of producers.
Conclusion
To increase the effectiveness of research in this area, such studies should be done dynamically and for at least two or more years. In the first year, the input consumption pattern should be extracted and after performing the consumption pattern modifying interventions, the effect of these actions should be evaluated in the following years. Data envelopment analysis methods and multi-objective genetic algorithm can be well used to develop solutions to improve input consumption patterns. The review of articles showed that the study of the effect of social factors on the behavior of various production systems has been neglected. Since the pattern of energy consumption in the agricultural sector is significantly dependent on the behavior of users and the characteristics of systems and methods of production, it seems necessary to pay attention to this factor to prepare and design any process improvement strategy in the system. In this study, a new procedure including three stages of analysis, redesign, and evaluation was proposed to complete the studies related to the analysis of agricultural systems.

Abstract Introduction
Steam generation system is a crucial and essential part of food industries which generates and distributes steam for consumption in domestic production units. Energy analysis based on the first law of thermodynamics was employed as the basic approach to assess energy systems. However, the energy approach does not provide information on the degradation of the energy quality occurring within energy systems and is, therefore, insufficient for sustainable design or optimization goals. Nevertheless, exergy analysis based on both the first and second laws of thermodynamics can overcome shortcomings of energy analysis. In the present study, the performance of equipment of the steam generation system in Pakdis’s juice production Company located in Urmia is investigated. Owing to the energy and exergy analyses, the sites with the highest loss of exergy are identified as the critical points of the process.
Materials and Methods
In this study, the steam generation unit of a juice production company located in Urmia, West Azarbaijan province in Iran was exergetically analyzed. Using mass, energy, and exergy balances for each component of the unit, the thermodynamic objective functions including the exergy efficiency, exergy destruction rate, exergy loss rate, and the potential improvement rate were assessed. After data acquisition, energy and exergy analysis of this unit was achieved by solving the related equations with the help of thermodynamic properties along with programming in EES software package.
Results and Discussion
The results showed that the highest exergy efficiency of 98.44% was assigned to the steam distributor (O) of the unit with a potential improvement rate of 1.51 kW and an exergy loss rate of 68.80 kW, as well as the pump (M) before the fourth boiler with an exergy efficiency of 19.69%, had the lowest value of exergy efficiency. The values of 12.55 and 11.93 kW were obtained for the exergy destruction rate and its potential improvement rate, respectively. The highest exergy destruction rate of the unit was for the first boiler with a value of 12391.80 kW, with an efficiency of 19.55% and a potential improvement rate of 10295.26 kW.
Conclusion
With regard to the energy and exergy analyses of the steam production system, more than 98% of the exergy destruction rate of the entire steam generation system was assigned to boilers, which had a major contribution to the exergetic efficiency of the system. The highest percentage of potential improvement was related to the first boiler and also the third boiler had the highest exergy loss rate, although the lowest exergy loss rate was the expansion tank of the system. In general, this study demonstrated the importance of exergy analysis for detecting the system components with the highest exergy destruction, which can be a breakthrough to identify these components and provides suitable solutions to improve the overall exergy efficiency of the steam-generating system.

Abstract Introduction: Almost 18 percent of emitted greenhouse gasses in Iran come from livestock industries, especially from manure decomposition. With the anaerobic digestion of animal wastes, in addition to eliminating its disadvantages, biogas as a clean and renewable energy carrier is produced. In addition, the resulting sludge is a more healthy and nutritious fertilizer for use in agriculture. One of the challenges of the bio-gas industry is to increase gas production efficiency. Various approaches are proposed to enhance manure digestion efficiency and increase biogas production, which can be mentioned below: Changing operating parameters such as temperature, hydraulic retention time (HRT), and particle size of the substrate; adding some effective additives; returning the resulting sludge into the digestion process and using bio-filters. Therefore in this study, in order to increase biogas production from poultry manure, two methods (co-digestion with rumen contents, and chicken intestine and its contents, and returning the slurry into the reactor) were tested. The alkaline composition of chicken manure and its high content of ammonia makes it difficult to digest alone, and co-digestion with high-carbon organic matter improves its digestibility.
Materials and Methods: Polyethylene bottles were used as batch reactor units. In order to the possibility of gas exit, as well as taking samples of the digester, two valves were placed on the bottle cap. All digesters were placed in a hot water bath and a 700 watts electric heater and a thermostat were used respectively to supply heat and to keep the temperature constant. A U-shaped tube, connected to the reactor output pipe was used to measure the amount of produced gas. The volume of water removed from the tube was an indicator of produced gas. The experiment was carried out in two stages. In the first stage 21 reactors were used according to the design of the experiment which was a completely randomized design with 7 treatments (adding rumen fluid in three levels (10, 20, and 30 percent of chicken manure (weight basis), respectively), adding chicken intestines and its content in three levels (10, 20, and 30 percent of chicken manure (weight basis), respectively), and control treatment), and three replicates of each treatment. During the whole experiment period, the pH and temperature were kept constant, respectively between 7.2-8.2 and 40-35 °C (mesophilic range). In the second stage of the experiment, after all the treatments reached the end of their hydraulic retention time, the resulting sludge was filtered and the liquid part was returned to the cycle. Three treatments were also provided here (supplying 50% of the water required by sludge liquid, supplying 100% of the water required by sludge liquid, and control treatment (no liquefied sludge).
Results and Discussion: Based on the results, although the type of organic supplementation had a significant effect on the amount of biogas production, the quantity of them had not. Treatments of chicken manure + 20%, 30%, and 10% of chicken intestines resulted in the highest amount of biogas production, respectively. But these three treatments were not significantly different. Also, the co-digestion of chicken manure with chicken intestines was more effective than the co-digestion of chicken manure with rumen fluid. The return of sludge, resulted from anaerobic digestion of chicken manure, again into the cycle, in addition to enhancing the amount of produced gas, can reduce the waiting time to start gas production by at least six days (in the treatment of providing 100% of required water from returned sludge). This can lead to continuous gas production and availability of sufficient gas in commercial gas-producing units. The effect of treatments on the time of reaching the cumulative gas production index to 100 mm was significant (α= 5%) and treatment of S₁₀₀ reduced this duration by approximately 17 days (65%) and S₅₀, for approximately 16 days (74%).
 
Conclusion: According to the results of this study, co-digestion of chicken manure with cow rumen fluid did not have a significant effect on the increase of biogas production, but co-digestion of chicken manure with chicken intestine and its contents (at least by 20% of chicken manure (weight basis)) can have a significant effect on the increase in the production of biogas and can increase the amount of gas at least twice. The highest amount of gas volume was about 305 Ml.gr^-1  VS_added and came from the treatment of co-digestion of chicken manure with 20% (weight base) chicken intestine and its contents. The return of the resulting sludge of anaerobic digestion of chicken manure, back into the cycle, in addition to increasing the amount of gas, can minimize the time it takes to start to produce gas and help to produce gas continuously. Moreover, the water used for digestion will also be significantly reduced (at least 50%).

Abstract Introduction: Bagasse is the dry pulpy fibrous residue that remains after sugarcane stalks are crushed for juice extraction. Bagasse is widely used in conversional and by-product industries. Bagasse is commonly used as a substitute for wood in many tropical and subtropical countries for the production of pulp, paper, and board. One of the most important conversional industries in the sugarcane agro-industry is chipboard production. In recent years, two chipboard factories from bagasse were exploited in Khuzestan province. In the production of chipboard from bagasse, a lot of waste is produced, most of which include pith. The waste is transferred to the outside of the factory at a great cost and energy level. Also, annually, a large amount of surplus bagasse of conversional Industries is obtained in Khuzestan agro-industries. These wastes cause many environmental and health problems, while these wastes can be used to generate energy. On the other hand, chipboard industries consume a lot of energy which is mostly fossil energy. Nowadays, in many sugarcane agro-industries in different countries, wastes are used to generate energy for sugar plants and conversional industries. Bagasse is often used as a primary fuel source for sugar mills.
Materials and Methods: Current research is focused on the direct energy consumed in chipboard production from sugarcane bagasse and whether it can be provided by using residues and wastes of Debal Khozaie Agro-Industry Company. Data were collected from agro-industry companies as well as by sampling and measuring waste, input and energy consumption at the chipboard factory of Debal Khozaie. Direct energy consumed in the chipboard production from bagasse includes diesel fuel, electricity, natural gas, and labor. Input and output values of materials (bagasse, pith, etc.), and energy consumption (electricity, diesel, natural gas, etc.) were collected using both laboratory tests and data available in agro-industry. Potential of energy generation from bagasse, pith, wood chips, and straw in Debal Khozaie agro-industry, were considered by the direct burning method. Also, the potential of biogas production from vinasse in agro-industry for energy production was calculated. The moisture of bagasse (fresh bagasse, 24 hours, five days, 30 days, and 45 days after gathering), outdoor dried pith, outdoor dried straw and wood chip were measured based on the ASTM D2974 standard method in the laboratory. Ash percentage of bagasse, peat, straw, and Wood chips were measured using a furnace, desiccator and a scale. Also, the lower heating value of bagasse, straw, pith, and wood chips were measured using a calorimeter bomb.
Results and Discussion: The direct energy consumption in the chipboard factory was determined to be 5.829 GJ m^-3 of produced chipboard. Natural gas and electricity were the major sources of direct energy with 78.52% and 18.87% share, respectively. To replace these sources, pith and woodchips form chipboard factory, sugarcane leaves, remainder sugarcane bagasse, and vinasse from molasses-based Razi alcohol factory were considered. Properties of the substituted resources were determined including ash, moisture content, heating value (using bomb calorimeter), and amount of woodchips along with the biogas potential from anaerobic fermentation of vinasse. Results showed that woody residues from chipboard factory and Debal Khozaie Agro-Industry Company had the potential to provide 4.33 fold the energy provided by gas in the chipboard factory, considering the efficiency equal to 60%. Using the residues of the chipboard factory individually, it is possible to replace all the consumed natural gas and electricity energy needed in the chipboard factory as well. According to the volume of available vinasse, the potential biogas production from this resource estimated to be 8.82 Gm³.
Conclusion: Electricity, natural gas, and diesel fuel constitute the direct energy consumed in the production of chipboard, and natural gas with 78.52% has the highest share. Electricity accounts for 18.87% of direct energy consumption. The specific energy of chipboard production at the chipboard factory was 5.829 GJ m^-3. Only using the pith of chipboard factory can produce 2.85 times the total energy of natural gas consumed in chipboard factory. Investigation of the potential of biogas production from vinasse in Debal Khozaie agro-industry showed that it is possible to generate energy equivalent to 8824.3 thousand cubic meters of natural gas. Overall, the study showed that using the wastes of chipboard factory and sugarcane agro-industry has the potential to replace the entire natural gas and electricity consumption in chipboard factory.

Abstract Introduction
The need to develop alternative energy sources especially renewable energy has become increasingly apparent with the incident of fuel shortages and escalating energy prices in recent years. With the advent of renewable energy, various studies have been conducted to investigate the potential of biogas production from agricultural waste. Considering the importance of retention time and methane production potential for designing industrial digesters, many studies on potential analysis and modeling of the digestion process of different products have been carried out by various researchers. These studies are valuable for the design and implementation of anaerobic digesters. Apple is one of the most popular fruits in many parts of the world and is widely cultivated in many temperate regions of the world. Considering the large volume of apple waste in Iran, this study was designed based on potential evaluation and modeling of biogas production from apple pulp.
Materials and Methods
In order to measure the potential of biogas production from apple pomace, a number of lab-scale digesters with a capacity of 600 ml and a working capacity of 400-500 ml were made. pH and C/N ratio were modified by adding NaOH and urea solution, respectively. Three different temperature treatments including psychrophilic (ambient temperature), mesophilic (37ºC), and thermophilic (47ºC) were applied to the substrate. Used pomace samples were collected from the output of an apple juice factory in southern Isfahan province, Iran. Anaerobic Biodegradability (ABD) was obtained by dividing the experimental methane production potential (BMP) obtained from the experimental results on the theoretical methane production potential. Three most common kinetic models of Gompertz, Logistic, and Richards were used to predict and stimulate the cumulative methane production of treatments.
Results and Discussion
Under ambient temperature, the digestive process took a longer time, and the time of maximum dilly biogas production was considerably more than the other two treatments. Statistically, production time and peak time of this treatment was higher than the other two treatments at 1% significance level. Maximum daily biogas production in the ambient treatment was observed on day 37th with a volume of 6.99 g-VS-1 ml, while maximum daily biogas production in the treatments of 37 °C and 47 °C were observed on days 22th (20.16 ml g-VS-1) and 20th (25.57 ml g-VS-1), respectively. In all three treatments, daily biogas production increased sharply in the first incubation days and after that reduced and then production increased again. In mesophilic and thermophilic treatments, the production of biogas modestly stopped after 35 days, but under the ambient temperature, the process of production continued after 55 days. The methane concentration of biogas in the psychrophilic treatment was significantly lower than the other two treatments at 1% level. Two treatments of 37°C and 45°C have a significant difference in methane yield at 1% level. Nevertheless, the production of biogas in two treatments was not statistically different. In all three treatments, the lowest pH was recorded after 7 days of production and the highest pH was recorded on days 34-40. All three kinetic equations were able to simulate the methane production process with high precision, although the results of the Logistic model provided higher accuracy. In the treatment 47 °C, the efficiency of the studied equations was higher than other treatments and models were able to predict the production process with higher accuracy. Results of the experiment show the high biochemical methane production potential of apple pomace (473.17 ml g-VS-1), which under laboratory condition of this study up to 63.9% of this potential (302.70 ml g-VS-1) was obtained. 
Conclusion
This study results are valuable for the design and implementation of industrial digesters. The results indicate the apple pomace has a high potential for the production of methane and its biodegradability is high. Apart from pH that is acidic, other apple pulp factors are appropriate for the activity of methanogenic bacteria. In terms of nutrients, apple pomace is also a good environment for the growth of anaerobic bacteria.

Abstract Introduction
Knowledge of mechanical and viscoelastic properties of agricultural material will be helpful in the transportation and processing of these materials. Giant reed grass, also known as wild cane, is a tall, perennial, bamboo-like, grass that grows in wet areas.  The giant reed grass can flourish in a wide variety of soils, including coarse sands, gravelly soil, heavy clay, and river sediment.  This grass attains heights of 7 m and once established the stems can reach a thickness close to 3 cm.  The stems of giant reed grass are used for different purposes. Traditionally the stems are used in the villages for fencing, roofing, and producing handcrafts. The modern uses of the giant reed stems include plywood, composites panels and paper production. The giant reed stems are not uniform and are made from many nodes. The number of nodes and the distance between nodes can affect the mechanical properties of the stems. In order to attain a suitable use of the stems in various industries, the physical and mechanical properties of the stems must be determined. Knowledge of mechanical and viscoelastic properties of agricultural material will be helpful in transportation and processing of these materials. The purpose of this research was to determine some relevant mechanical properties of the stems of giant reed grass with different nodes and moisture contents.
Materials and Methods
In this research, different mechanical and viscoelastic tests were performed on the stems of cane at various levels of moisture and number of nodes. The Burger-Voigt model with different number of elements was also used to model the creep behaviors of the stems. The cane stems were cut and divided to three groups of two, four, and six-node stems. The moisture contents of the stems were adjusted to three levels of 30, 40 and 50% (w.b.). After preparing the stems the mechanical tests were performed using an Instron testing machine with a three-point support. The creep tests were done by hanging a 10 kg weight at the middle of each stem. The experiments were done using factorial tests based on completely randomized design. The Young module, toughness, and the yield points of the stems were measured by the three-point method. These parameters were obtained from the stress-strain curves of the three-point compression bending tests. The results showed that the Young module was affected by both moisture and the number of nodes, but there were no interaction effects. The creeps of the stems under 10 kg loading were modeled using 3 to 5 elements Burger-Voigt models. In these models a combination of springs and dashpots are used to represent the stems. The curve fitting was performed using the MATLAB software and the goodness of fitness was verified using the fitted curves and calculating the coefficient of determinations.
Results and Discussion
The results by investigating the graphs and the ANOVA tests showed that the Young module was significantly affected by both moisture and the number of nodes. The obtained Young module for cane stem ranged from 572-1268 MPa. Both yield point and toughness were affected by both moisture and the number of nodes and their values were 65-250 N and 0.016-0.132 J.m^-3, respectively. The creep test results indicated that the maximum deformation and maximum time for of the interaction of the two factors was insignificant. The maximum deformations ranged from 2.1-42.5 mm, and the maximum time for reaching the final deformation was 12.5-75 minutes for various moistures and the number of nodes combinations and showed that the 5-element Burger was best for explaining the viscoelastic behavior of cane stems (R²>0.97).
Conclusion
In this research, some mechanical properties of the giant reed grass stems were measured and the creep behavior of the stem was modeled using 3-5 elements Burger-Voigt models. The results indicated a decrease in the Young module of the stems with increase with moisture content and increase in the Young module with increase in the number of nodes. On the other hand, the elongation of the stems increased with both number of the nodes and the level of moisture. The 5-element Burger-Voigt model was best fitted to the creep data.

Abstract Introduction
Cantaloupe is a one-year-old herb of gourds and edible fruit with very good properties. Cantaloupe is one of the best sources of vitamin A and is rich in beta carotene, which is converted into vitamin A in the body. In addition, it contains other useful nutrients such as potassium, steel, fiber, magnesium, iodine and vitamins B5, B3, B6 and B1. Life cycle assessment in recent years has become an appropriate tool for assessing environmental impacts in agricultural and food industries. The purpose of this study was to evaluate the life cycle assessment of this horticultural crop in terms of energy consumption and the environmental impacts in the city of Iwan West, Ilam province.
Materials and Methods
The data were collected from dryland cantaloupe producers in the city of Iwan West, Ilam province using questionnaires and interviews were collected from farmers. In this study, four important energy indices were energy use efficiency (EUE), energy productivity (EP), specific energy (SE), and net energy gain (NEG). Environmental impacts on dryland cantaloupe production were evaluated using a life cycle assessment approach and the obtained indexes were calculated using the CML 2 baseline 2000 model. Ecoinvent databases were used to access needed information and data analysis was done with Simapro software. In a life cycle assessment project, all production processes of a product from the stage of extraction of materials to disposal of the remaining waste from the product are reviewed and the results of the reduction of environmental degradation are applied. Each life cycle assessment project has four essential steps including, goal and scope definition, life cycle inventory, environmental impact assessment, and interpretation.
Results and Discussion
Input and output energy analysis in dryland cantaloupe production
The total input and output energies for dryland cantaloupe were calculated to be 39021.59 and 39190.43 MJ ha^-1, respectively. Diesel fuel, agricultural machinery and nitrogen fertilizers were the most widely used energy inputs with 51%, 24%, and 14%, respectively. Energy use efficiency for dryland cantaloupe production was calculated at 1.004.
Analysis of environmental impacts in dryland cantaloupe production
In this study, the global warming potential per produced product in dryland cantaloupe production was estimated to be equal to 202.45 kgCO₂ eq. from among inputs, diesel fuel had the most impact on the effects of abiotic depletion and ozone layer depletion, and in all parts of the effects of agricultural machinery and nitrogen fertilizers, the largest share of pollutants was allocated. The results of normalization showed that the effect of marine aquatic ecotoxicity and freshwater aquatic has the highest environmental burden on dryland cantaloupe production.
Conclusion
The results of energy analysis showed that the total energy inputs were equal to 39021.59 MJ ha^-1. Among inputs of diesel fuel, agricultural machinery, and nitrogen fertilizer were the most consumed energy inputs. The energy use efficiency index and the net energy in this study were 1.004 and 168.84 MJ ha^-1, respectively. The results of environmental impacts had shown that diesel fuel, nitrogen fertilizer, and agricultural machinery had been most affected. It is recommended that proper management of agricultural machinery, equipping fields with new and suitable machines and avoiding the use of tractors and worn-out tools should be put in order to minimize the energy consumption and environmental pollutants generated by the production. Less use of chemical fertilizers (especially nitrogen) and its replacement with organic fertilizers can also be affected.

Abstract Introduction 
Agriculture is an energy conversion process. In this process, solar energy, fossil fuel, and electricity are converted mainly into food and fiber. In the agricultural section, the trend of energy consumption increases rapidly every year. Constraints on agricultural land, population growth, changes in infrastructure, and a trend towards high living standards have contributed to increase energy use in the agricultural sector. Fuel, electricity, machinery, seeds, chemical fertilizers, and chemical pesticides have a significant share in supplying energy sources. Effective use of energy in agriculture reduces environmental problems and prevents the destruction of natural resources and develops sustainable agriculture as an economic production system. Wheat is the most strategic crop in Iran that more than 50.39% of arable land belongs to wheat.  
Materials and Methods
The current study has been done with the objects of evaluation of inputs and crop yield, input and output energy, and energy indices for irrigated wheat for seven provinces such as Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan. For this purpose, the required information gathered via study of publications, face to face interview with experts and leading farmers, and questionnaire completion by the irrigated wheat farmers in different cities of each understudy province. Then, with the help of equivalent energy equations, input and output energy and energy indices were calculated. In this research, simple random sampling method was used.
Results and Discussion
According to the results, total input energies of Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan provinces were calculated with 45458.84, 92714.8, 38755.34, 104701, 50971.2, 26198, and 49362. 64 MJ ha^-1 respectively, while the output energy for those provinces were 162169.28, 131958.8, 77381.39, 122297, 141901.2, 134106, and 125511.69 MJ ha^-1, respectively. The maximum share of energy input for Alborz, Ardebil, Khuzestan, Golestan, and Hamadan provinces were regarding to chemical fertilizers with amounts of 43.06, 43.16, 58.33, 38.05, and 47.57 percent, respectively, while irrigation energy requirement had maximum share in Isfahan and Khorasan-e Razavi with 62.36 and 57.17 percent, respectively. The minimum share of energy input for Alborz, Isfahan, Ardebil, Khorasan-e Razavi, and Golestan provinces was calculated for labor energy requirement with 0.39, 0.29, 0.79, 0.18, and 0.26 percent, respectively, while in Khuzestan and Hamadan, chemicals consumed the lowest energy with 0.55 and 0.89 percent, respectively. Share of direct energies for all understudy provinces were 44.61, 72.13, 41.22, 67.48, 30.75, 39.44, and 39.91 percent, share of indirect energies were 55.39, 27.87, 58.78, 32.52, 69.25, 60.56, and 60.09 percent, share of renewable energies were 27.99, 65.91, 32.35, 60.57, 19.26, 34.92, and 35.16 percent, and share of nonrenewable energies were 72.01, 34.09, 67.65, 39.43, 80.74, 65.08, and 64.84 percent, respectively. Energy ratio for Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan provinces were 3.57, 1.42, 3.48, 1.17, 2.78, 5.12, and 2.54, respectively, and energy productivities were 0.26, 0.11, 0.26, 0.08, 0.21, 0.38, and 0.18 kg MJ^-1, respectively. Average input energy, output energy, energy ratio, energy productivity, and net energy gain for all provinces were 58308.83 MJ ha-1, 136092.15 MJ ha^-1, 2.87, 0.212 kg MJ^-1 and 77783. 31 MJ ha^-1, respectively. Total input energy cost for irrigated wheat production was 57.966 ×106 Rial ha^-1. The Energy intensiveness, Energy intensiveness value, Energy intensity cost, and Energy ratio cost were found as 1.299 MJ (103 Rial)^-1, 0.641 MJ (103 Rial)^-1, 10853.05 Rial kg^-1, and 1.21, respectively.
Conclusion
In order to reduce the share of indirect energy and non-renewable energy, organic fertilizers should be replaced by chemical fertilizers and plant residues in the field. Minimum tillage should also be used in land preparation operations to reduce fuel consumption, maintain organic matter and soil moisture and reduce soil erosion. To compensate for some of the elements taken from the soil by the plant and the increase of organic matter and fertility of the soil, it is recommended to return part of the plant residues to the soil. The use of combined machines that can perform several simultaneous operations and minimizing and protecting soil tillage to reduce fossil fuel consumption through minimum use of machinery should be investigated as a national necessity.

Abstract The aim of this study was to investigate the energy consumption and production costs of sweet-cherry and sour-cherry in Northeastern Iran. Required data were collected from 75 sweet-cherry and 42 sour-cherry producers. The total energy inputs in sweet-cherry and sour-cherry production were estimated as 37.76 and 31.03 GJha^-1, respectively. The energy efficiency of sweet-cherry production was greater than sour-cherry production. Chemical fertilizers and diesel fuel were the most highly consumed energies in both crops. The higher share of non-renewable energies consumed to produce sweet-cherry than sour-cherry revealed that sweet-cherry production was more dependent on non-renewable sources compared with the sour-cherry production. The economic analysis revealed that production costs for sweet-cherry were higher than sour-cherry but sweet-cherry was more profitable than sour-cherry because of premium prices for sweet-cherry. The modeling results showed that the human labor input had the most impact on costs of both crops. As a consequence, the main practical solutions could be saving in diesel fuel and fertilizer management, which could more properly overcome economic and energy problems in the two crops.

Abstract Contamination due to hydraulic fluids exerts deleterious effects after a long time, however this factor is often ignored or its consecutive breakdowns and system failures are considered due to other factors. Therefore, in order to prevent the likelihood of occurring such problems, the following two strategies are presented: using oil change method to replace all of the hydraulic fluids from the discharge system with the new oil and using offline hydraulic oil filtration system for the removal of contaminated oil particles. In this regard, the present study aimed to investigate the economic status of cane sugar harvesting machines with an emphasis on hydraulic oil filtration process in seven units of sugarcane developmental company and affiliated industries in Khuzestan province, Iran. To perform this study, all statistics and data of the sugarcane and affiliated industries in seven companies during the crop year 2011-2016 were collected and classified. The results indicated that the application of the hydraulic filtration method led to the oil consumption saving (per liter) and in price (Iranian Rial) during the three crop-years of 2014-2016, as following: Imam Khomeini: 25500 L and 2882154363 Rials, Amir Kabir: 49000 L and 5847389466 Rials, Hakim Farabi: 82000 L and 9534396744 Rials, Dabal Khazaee: 73400 L and 6808230362 Rials, Dehkhoda: 31680 L and 3421979639 Rials, Salman Farsi: 73500 L and 7606675370 Rials and Mirza Koochak Khan: 75934 L and 8083068395 Rials.

Abstract Introduction
Large industrial factories often discharge significant quantities of low-pressure steam (dead steam) into the atmosphere, which causes energy losses. Retaining low-pressure steam content reduces boiler load, resulting in energy savings and lower costs for the fuel consumption (for example, gas consumption bill in a factory). The boosted-pressure steam is used in processes such as distillation, hot water production, space heating or vacuum generation. If the vapor pressure for the intended application is low, a thermo-compressor is able to increase the pressure and temperature to the required level. Thermo-compressors are a special type of gas compressor that uses an actuator to compress secondary fluid and does not have any blades or moving parts. The accurate prediction of the thermo-compressor performance improves the reliability of this process and increases its efficiency.
Materials and Methods
Two important characteristics for the current thermo-compressors are entrainment ratio (ER) and compression ratio (CR). The first is the dimensionless mass flow rate, and the second is the dimensionless pressure. The wet steam theory as a classic theory is used by Wolmer-Frankel-Zeldovich to calculate the amount of liquid particles. In order to select the best geometry for the thermo-compressor among all possible geometries, the performance of each model must be compared with other models. In following, the case that includes characteristic parameters associated with the target values has been selected.
The commercial Ansys Fluent Versions 15, based on the finite volume method (FVM) was used to simulate and monitoring the flow behavior inside the thermo-compressor. The governing partial differential equations (PDE) were solved implicitly using a density-based solution. The convective heat transfer terms were discriminated based on the second-order upwind scheme. The non-linear governing equations were solved using the implicit coupling solver and the standard wall function was used near the wall. Given the three-dimensional flow for steam, the equations of mass conservation, momentum, and energy were written. The Realizable  model was used to simulate turbulences in the flow.
Results and Discussion
A summary of the results is presented in terms of the results of pressure, velocity magnitude, Mach number and temperature. A general understanding of this characteristic for a thermo-compressor is extremely important for recognizing the fluid flow inside it, and it is very useful for practical use. Pressure is the most important factor in the recharge section of a thermo-compressor. Increasing the recharge vapor pressure in a thermos-compressor revival the dead steam and increases the steam efficiency. The revival steam can be used in other parts because of their high thermal content. Another important factor in the study of flow behavior inside the thermocouple is velocity magnitude. This quantity, which is closely related to the concept of momentum inside the thermocouple, had high influences from high pressure inputs as well as the thermo-compressor geometry. The highest amount of velocity occurs after the initial nozzle and had a very high magnitude (1000 ms^-1), which was also remarkably high in Monnet's terms. Another important characteristic of a flow is the temperature of the stream. The high input temperature associated with motive vapor at the outlet of the primary nozzle was sharply reduced, even in some section reached to 110 °Kelvin. Due to the very high flow momentum in this section, the fluid phase remained gas and it can be justified from the point of view of the fluid dynamics.
Conclusion
Considering the importance of thermodynamic properties of steam in conversion and industries, it would be extremely beneficial to fully understand the interactions inside the thermocouple compressor. The importance of the discussed characteristics is more specific when there is a close relationship between each of these factors and energy consumption in a factory or in any industrial production unit. It was observed that the designed thermos-compressor was able to increase the velocity and temperature in a desirable range for the conversion of non-consumable vapor to the pressure and temperature. It was concluded that the Realizable  model due to the prediction of the jet characteristics appearing in the flow regimes for axial symmetry had a high ability to simulate fluid flows inside the thermos-compressor.

Abstract Introduction
Soil compaction reduces soil porosity and thus, increases the resistance and bulk density of the soil. These changes limit water and air movement and root penetration in the soil and ultimately, they may reduce the seed germination and the crop yield. For planting sugar beets, tractors and equipment need to move several times on the ground, which is a factor in soil re-compaction and the loss of the effects of previous tillage. Therefore, if, after planting, inter-row tillage was done, it can have a positive effect on reducing the bulk density of the soil and it may even increase yield.
 
Materials and Methods
An experiment was conducted to determine the effect of inter-row tillage on the sugar beet yield and its quality and water use efficiency during two years cropping period (2016-2017) in Ekbatan Research Station, Hamadan with loam texture soil. A strip plot experiment with eight treatments and three replications was used. Irrigation regimes consist of 100% of sugar beet water requirement (I1) and 75% of sugar beet water requirement (I2) were considered as main plots. Inter-row tillage operations consist of  combined cultivator equipped with chisel and crescent blades to 20-25 cm soil depth (T1), a simple cultivator equipped with crescent blades (T2), crescent cultivator + inter-row subsoiling to 30-35 cm soil depth (T3), combined cultivator equipped with rotary and sweep blades to 20-25 cm soil depth were considered (T4 ) as sub-plots. During the experiment, some physical properties of soil including bulk density and soil cone index were measured. At the end of the growth season, the root yield and yield of white sugar were measured and analyzed statistically.
Results and Discussion
The results showed that the effect of inter-row tillage methods on the soil bulk density and soil cone index was significant. The T3 treatment (crescent cultivator + inter-row subsoiling to 30-35 cm soil depth) had the highest effect on reducing the cone index and bulk density of soil, but the lowest root yield was obtained.  Due to the low spacing of rows (50 cm) in the sugar beet cultivation, as well as the structure of the subsoiler and its depth, it is possible that the subsoiling caused the moving of the roots and minor damage to it. The effects of irrigation and inter-row tillage and their interactions on quantitative and qualitative yield of sugar beet were not significant. The results of analysis of variance of treatment effect on the water use efficiency showed that the effect of inter-row tillage on the water use efficiency was not significant. The effect of water requirement on the water use efficiency on the basis of sugar and white sugar performance was significant at 5% probability level. The treatment of 75% of water requirement increased the efficiency of water use based on the root yield, sugar yield and white sugar yield by 4%, 14% and 7%, respectively. Therefore, with the goal of reducing water consumption and not significantly reducing the yield, after plant establishment, it can reduce water use by about 25%.
Conclusion
The effect of inter-row tillage on the cone index and bulk density of soil was significant and subsoiling treatment caused a further reduction of these two indices compared to the other inter-row tillage methods. The effect of inter-row tillage and water requirement on root and sugar yields was not significant. According to the results, after planting completely establishment, the water use can be reduced by about 25% (this decrease in the total length of sugar beet growing was about 15%).

Abstract Introduction
Considering the high consumption of diesel fuel in the agricultural sector, it is necessary to find solutions to reduce its consumption, and it will be feasible to have a convenient mathematical model more easily and transparently.Fuel and lubrication costs range from at least 16% to more than 45% of total machine costs, depending on the type of fuel and the amount of time that the tractor or the machine carries out for agricultural operations. Therefore, the fuel consumption index has a significant role in the selection and management of tractors and agricultural equipment. Most budgeting models also use a simple method to estimate the consumption of diesel fuel, but it is needed a model that describes the real conditions of agronomic operations used to compare agricultural machinery management policies.
Materials and Methods
This case study was conducted in Parsabad city of Moghan, the northernmost province of Ardabil province. The main agricultural products in Pars-Abad Moghan include wheat, maize, maize, canola and sugar beet. The product of this study was irrigated wheat with a crop area of 18042 hectares.In this study, in order to create homogeneous conditions in the study of diesel fuel consumption and the ineffectiveness of the type and model of tractor in it, only diesel fuel consumption was considered by the tractor MF-399. Selection of sample farmers was also carried out among owners of this type of tractor. Selection of owners of tractor MF-399 in Pars-Abad Moghan city was done by random sampling method. For this purpose, Cochran formula was used. Two-way flexible and non-flexible models have been used to predict the diesel fuel consumption. The model used includes the Cobb-Douglas function and transcendental function. Statistical calculations in this study were performed using Excel software and SPSS16 software.
Results and Discussion
For comparing the best form of the fuel function, the test formulas for the comparison of the form of functions such as bounded least squared F, LR test, White test, Breusch-Godfrey test and Rigorous test were used. Diagnostic statisticians (well-fitting coefficient), the normal distribution of distorted sentences, and the heterogeneity of variance showed that both forms were acceptable. Based on the LR statistic, zero statistics did not rule out the discrepancy between the two coherent models (Cobb-Douglas) and non-dominant (transcendent), but the coherent model was preferable to be the transcendental model because of its simplicity and power of explanation.
According to the estimated model, the duration of soil tillage operations had a positive stretch in diesel fuel consumption and, among other variables, had the highest elongation. It should be noted that the average time required for tillage operations was 387.6 min ha^-1, which will save 0.31 L ha^-1, if one percent of this time (3.9 minutes) is reduced. Thus, the value of the amount of gasoline saved will be about 990 Rials per hectare and equal to 7.7 percent of the value of one kilogram of wheat. Therefore, if the operating time is reduced at the macro level of the country, a significant amount of cost will be saved. Therefore, it is imperative that farm managers take time management in serious soil tillage operations and try to reduce this time.
So that, in exchange for an increase of 1% over the duration of the tillage, a fuel consumption of 0.6% would be increased. It is also clear that an increase of 0.6% in fuel consumption for tillage operations is significant, indicating the fact that farm managers have made the need for time management, especially in the tillage operations, to reduce this time. According to the estimated model, the duration of the planting operation also had a positive stretch in the consumption of diesel fuel. So that, in exchange for an increase of 1% over the duration of the planting operation, a fuel consumption of 0.04% would be increased.
Conclusion
Use of the Cobb-Douglas model with five sentences and four independent variables including cropping area, soil tillage operation time, planting time and weeding operation time in order to predict the amount of diesel fuel used to produce wheat, had acceptable results and as a predictive model with low complexity but with high precision, can be easily used in annual budgeting for the production of wheat.

Abstract  Introduction
The researchers have been currently focused on replacing fossil fuels by biofuels to reduce dependence on fossil fuels.  Biofuels provide low greenhouse emissions with the reduction of oil import. The biofuels can play an important role economically becomes more clear when their relatively developed agricultural sector is taken into account. Bioethanol, biodiesel and to a lesser extent pure vegetable oils are recently considered as most promising biofuels. Since 19 century, ethanol has been used as a fuel for the diesel engines. The cost of bio-diesel for IC engine is slightly greater than that of diesel oil. The specific fuel consumption, a function of the engine speed, is higher in bio-diesel than in diesel oil. The results previously of Bench-test indicated that the average value of SFC for bio-diesel was 17% greater than that of diesel oil. As for the properties of biodiesel, the lower heating value, higher density and higher viscosity play a primary role in engine fuel consumption for biodiesel. Most of the authors, who agreed that fuel consumption increased for biodiesel compared to diesel, contributed to the loss in the heating value of biodiesel. Of course, some authors only explained the increased fuel consumption as the result of the higher density of biodiesel, which causes a higher mass injection for the same volume at the same injection pressure.
Materials and Methods
The equipment and instruments used in the present research were a diesel engine (OM 314), a dynamometer, a dynamometer control panel and a fuel tank. A four-cylinder direct injection diesel engine, model OM 314, made by Idem Company, Tabriz, Iran, was used to conduct the experiments. The fuel used in the present research was from waste oil. Ethanol was also used to feed the engine. The blends of diesel–ethanol–biodiesel were prepared on a volumetric basis. The experiments were conducted based on the response surface methodology and using Central Composite Rotatable Designs (CCRD). The response surface methodology, as one of the best methods to optimize processes and determine the effect of different variables on the responses, has special popularity among researchers. Applied research design in this study was CCRD that has the most application among other designs of the method. Independent variables were different ratios of ethanol, biodiesel, and diesel, engine load, and engine rotational speed and responses were included engine brake specific fuel consumption.
Results and Discussion
The P-values for both total and prediction models of specific fuel costs were less than 0.01. This result showed that the models statistically have high abilities to predict the impacts of independent variables on specific fuel costs at 1% probability level. The linear, quadratic and interaction of the overall model had a P-value less than 0.05 that indicated their statistical validity. The specific fuel costs decreased for all blends by increasing the engine load. The reduction of specific fuel costs was more aggressively observed in low loads. With increasing engine rotational speed, the specific fuel costs were increased at low loads and at middle and high loads it was decreased and then increased. The increasing of volume ratio of biodiesel in the blended fuels, specific fuel costs were increased. By increasing the volumetric ratio of ethanol and biodiesel, specific fuel costs were increased due to lower calorific value and the direct relationship of this variable with brake power compared to that of diesel fuel in all test conditions and all fuel blends. By increasing of biodiesel ratio in the blended fuels, the specific fuel costs were increased at the low percentage of ethanol ratio. But by the increase of ethanol ratio the specific fuel consumption firstly was increased and then slightly decreased at high levels of biodiesel.
Conclusion
The minimum of the specific fuel costs (580 R kW^-1h^-1) occurred at full load and engine rotational speed of 2139 rpm for pure diesel (B0E0D100). Also, the maximum of specific fuel consumption was obtained by 9951 R kW^-1h^-1 at 20% engine load and rotational speed of 2800 rpm and for a fuel blend containing 0.8 l biodiesel, 0.4 l ethanol and 1l diesel (B45.2E36.6D18.2).
 
 

Abstract Introduction
In recent years, the exergy analysis method has been widely used in the design, simulation and performance assessment of various thermal systems. In this regard, this method may be applied to various types of engines for identifying losses and efficiencies. This analysis is based on the second law of thermodynamic. Exergy is a potential or quality of energy. It is possible to make sustainable quality assessment of energy.  In this study, the second law of thermodynamics is employed to analyze the quantity and quality of exergy in a fourstroke, four-cylinder, diesel engine using diesel fuel and biodiesel fuel.
Materials and Methods
Four experiment variables in the present study including the operating parameters, load and speed, and the added volume of biodiesel of diesel fuel were considered as effective factors on the Break  exergy efficiency. Designs that can fit model must have at least three different levels in each variable. This is satisfied by Central Composite Rotatable Designs (CCRD). Similar to the case of the energy analysis, the same assumptions were valid for exergy analysis; the whole engine was considered to be a steady-state open system. For exergy analyses, the entire engine was considered to be a control volume and a steady-state open system. Fuel and air enter, and mechanical work, heat loss and exhaust gases leave the control volume at a constant rate. The exergy balance for the control volume can be stated as.
                                                              
where  is the exergy transfer rate associated with the heat loss from the control volume to the environment, assumed to be through cooling water;  is the exergy work rate, which is equal to the energetic work rate;  is the mass flow rate;  is specific flow exergy; and  is the exergy destruction (irreversibility) rate.
 
Results and Discussion
exergy efficiency increased with increasing engine load. This relationship could be attributed to the reason that brake power increased with increasing engine load, and the other side, there was a positive direct relationship between brake power and exergy efficiency, resulting in an increase of exergy efficiency. Although fuel consumption increased along with increasing engine load, increase in the brake power was much greater than increase in the fuel consumption. On the other hand, an increase in the engine load enhanced combustor temperature which was provided an appropriate condition for combustion and caused an increase in cylinder pressure. At all engine operating conditions, with increasing engine speed, the thermal efficiency at first increased, at moderate speed reached to a maximum amount and finally with more increase in engine speed, the thermal efficiency decreased. The initial increase in thermal efficiency could be attributed to the increase in air to fuel ratio and engine torque which caused an increase in the brake power. Decreasing thermal efficiency in high levels of engine speed could be caused by a decrease in volumetric efficiency of the combustion chamber, because of the time limit on filling cylinder. With increasing biodiesel concentration in the fuel blend, exergy efficiency decreased. The reason could be due to the lower calorific value and the higher viscosity of biodiesel compared to diesel fuel.
Conclusion
At all engine operating conditions, the exergy efficiency of the engine increased with increasing engine load also with increasing percentages of biodiesel into synthetic fuel, exergy efficiency increased. 43.09% of the fuel exergy was completely destructed and was not convertible to work. The results of optimization indicated that the most exergy efficiency (37.72%) was occurred for the pure diesel at 2036 rpm and 95% load.

Abstract Introduction
Today, grapes are cultivated in a vast zone worldwide. Grapes are among the major horticultural produced in Iran and the country is ranked 10th in the world for the grape production. Therefore, efficient use of energy from this crop is very important. Energy is one of the principal requirements for the economic growth and development of agriculture. Scientific forecasts and analysis of energy consumption will be of great importance for planning the energy strategies and policies. The enhancement of the energy efficiency not only helps in improving competitiveness through cost reduction but also results in minimized greenhouse gas (GHG) emissions and environmental impacts. In other hand, energy analysis in the crop production systems enables to identify the effective farming system in different farm size with respect to energy parameters. Based on mentioned points, the objective of this study was to evaluate the energy flow of grape production in three sizes (small, medium and large) of land and then, the life cycle of the production in Hazavah Region of Arak city, Iran.
Materials and Methods
In this study, data were obtained from 58 growers using face-to-face questionnaires in Arak county of Iran. Orchards were selected using stratified random sampling. Investigation of the energy flow in a production system necessitate calculating input–output energies. In order to deal with this part, energy coefficients were taken into account to convert all agricultural inputs to their energy equivalent. In other words, each input was converted to its energy equivalent by multiplying the application rate of agricultural inputs used within the system by its energy coefficient. In order to evaluate how efficient, the system under study is, some well-known indicators have been introduced and widely applied when a production system is appraised. In this study, a life cycle approach was used for assessment of environment impacts of the grapes production. Life Cycle Assessment (LCA) refers to the process of compiling and evaluating the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle. Goal and scope definition, inventory analysis, life cycle impact assessment and life cycle interpretation are four mandatory steps, which should be followed in a full LCA study. The characterization factors used in this study were adapted from Simapro software which is linked to EcoInvent database.
Results and Discussion
On average, the values of consumed and produced energies were 1854 MJ ton⁻¹ and 11800 MJ ton⁻¹, respectively. Among all input energies, chemical fertilizers held the first rank with an amount of about 704 MJ ton⁻¹. It accounted for 38% of the total energy used in the production season.  Energy use efficiency, which is a ratio between output and input energy, was calculated as 5.75. Also, the energy productivity was estimated as 0.48, meaning that 0.48 kg grapes is produced when one MJ energy is consumed. The total Global Warming (GW) was calculated as 508.63 kg CO₂ eq. ton⁻¹. The farm size had an influential effect on the GW and other impact categories. An increase in the farm size led to reduction in the environment impacts. It means that the value of GW for large farms fell at 498.68 kg CO₂ eq. ton⁻¹ and the value of GW for small farms fell at 698.69 kg CO₂ eq. ton⁻¹. The upshot was that GW and other impact categories for large farms were significantly less than its counterpart in small farms due to the high value of grapes produced in large farm groups. Impacts of manure played a more important role on GW. Also, direct emissions of chemical fertilizers made high contribution to acidification and eutrophication. Management of using chemical fertilizers can be an appropriate way to reduce the acidification, eutrophication and other environmental impacts on the grape production.
 
Conclusion
Chemical fertilizers (38%), demonstrated their pivotal roles in total energy consumption. The direct emissions in the grape production resulted from high application of chemical fertilizers contributed considerably to some environmental impacts. It suggested establishing a sustainable and environmental friendly grape production system in the region with application of efficient fertilizers by integrated nutrient management.

Abstract Introduction
More than 40 percent of the world population is now dependent on biomass as their main source of energy for cooking. In Iran, the lack of access roads and inefficient transportation structure have made some societies to adopt biomass as the main energy source for cooking. In such societies, inefficient traditional three-wall cook stoves (TCS) are the sole method of cooking with biomass, which corresponds to the large fuel consumption and smoke emission. Biomass gasifier cook stoves have been on the focus of many studies as a solution for such regions. In these stoves, biomass is pyrolized with the supply of primary air. The pyrolysis vapors are then mixed with secondary air in a combustion chamber where a clean flame forms. In this study, a biomass cook stove was manufactured and its performance was evaluated feeding with three kind of biomass wastes (e.g. almond shell, wood chips, and corn cob).
Materials and Methods
A natural draft semi-gasifier stove was manufactured based on the stove proposed by (Anderson et al., 2007). It had two concentric metal cylinders with two sets of primary and secondary air inlet holes. It had 305 mm height and 200 mm diameter. The stove was fed by wood chips, almond shell, and corn cob. Thermal performance of the stove was evaluated based on the standard for water boiling test. It consisted of three phases of cold start, hot start, and simmering. Time to boil, burning rate, and fire power was measured in minute. A “K” type thermocouple was used to measure the water temperature. Emission of carbon monoxide from the stove was measured in three situations (e.g. open area, kitchen without hood, and kitchen under hood) using CO meter (CO110, Thaiwan).  
Results and Discussion
Neither particulate matter nor smoke was visually observed during the stove operation except at the final seconds when the stove was going to run out of fuel. The flame color was yellow and partly blue. The average time to boil was 15 min; not significantly longer than that of the LPG stove (13 min). Time to boil in hot phase was almost the same for all fuels which is not in line with the studies reported by (Kshirsagar and Kalamkar, 2014; Ochieng et al., 2013; Parmigiani et al., 2014). This is probably due to the stove body material. In fact, the hot phase test, aims to show the effect of the stove body temperature on the performance. In contrast with the most of the stoves, the one was used in the present study was made of a thin (0.3 mm) iron sheet which has a high heat transfer and low heat capacity. This results in a rapid increase in the stove body temperature up to its highest possible. The longest flaming duration (51 min) was observed by 350 g almond shell. Thermal efficiency on the other hand, was different in using different biomass fuels. The average thermal efficiency of 40.8 was achieved by the stove which is almost three times of open fire. The results from emission test showed that the average of carbon monoxide surrounding the operator in the case of open area, kitchen without hood, kitchen under hood, and traditional open fire were 4.7, 7.5, 5.2, and 430 ppm, respectively.
Conclusion
The amount of carbon monoxide emitted to the room is in accordance with the US National ambient air quality standards (NAAQS) hence, compared with traditional methods of cooking in deprived regions, the stove burns cleaner with higher efficiency. In order to prohibit respiratory decreases in housekeeping women, this stove could be disseminated in some deprived regions of Iran.