Research Article
Agricultural waste management
M. Khoshdel; S. J. Hashemi; S. M. Zabihzadeh; R. Esmaeilzadeh Kenari
Abstract
IntroductionThe use of agricultural waste to produce biodegradable containers is an appropriate option to solve the problem of biomass accumulation resulting from the cultivation of crops such as rice. The highest amount of agricultural waste compared to the area under cultivation is related to wheat ...
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IntroductionThe use of agricultural waste to produce biodegradable containers is an appropriate option to solve the problem of biomass accumulation resulting from the cultivation of crops such as rice. The highest amount of agricultural waste compared to the area under cultivation is related to wheat straw and rice straw, respectively. After wheat, rice is the most important agricultural product in human nutrition. According to the World Food Organization, the area under rice cultivation in the world is about 150 million hectares. The use of rice straw as a raw material for disposable cellulosic dishes can prevent straw residues in paddy fields, improve the deficiency of cellulosic raw materials, and reduce the use of plastic containers and the dangers thereof. Rice straw is a significant source for making cellulosic containers, but after making containers, hydrophobicity and microbial hazards can be among the problems of making these types of containers. The coating technique is one of the best solutions for resolving hydrophobicity and microbial problems. Coverage is very important and necessary to increase the shelf life of agricultural products and maintain their quality. Waxes are the best preventative methods against moisture and water vapor loss, and beeswax is one of the best edible waxes with these properties. The antibacterial properties of coatings with natural antioxidants will help solve the cellulose containers' problem. The main objectives of this study were to evaluate the endurance, hydrophobicity and antimicrobial activity of rice straw degradable cellulosic dishes.Materials and MethodsIn order to obtain the raw material for the manufacture of cellulosic dishes, the straw was digested with 10% and 20% sodium hydroxide, and then to weigh the hydrophobicity tests, tensile strength index and brightness, 120 Gr paper was made. Concentrations of 1, 2, 5 and 10% of the wax solution in ethanol solution were prepared and used as the first coating to improve the hydrophobicity. The nettle extract encapsulated with royal seed gum as the second coating to improve the antibacterial activity. Hydrophobicity and antimicrobial properties of the samples were measured and compared. The cup mold specimen was made of 2-piece steel and made using appropriate rice straw paste and coating with the appropriate concentration of the sample in disposable cellulose.Results and DiscussionThe results showed that increasing the amount of sodium hydroxide in baking conditions increased the tensile strength and the degree of clarity, but it had no effect on hydrophobicity. As the concentration of baking soda (sodium hydroxide) increases, so does the brightness. Increasing the concentration of sodium hydroxide increases the tensile strength, and the increase in tensile strength due to the increase in the percentage of sodium hydroxide can be due to the increase in the ability to form bonds between fibers due to the release of lignin. Honey wax with a 5% concentration was the most optimal coating for hydrophobic cellulose containers. With increasing wax concentrations in ethanol solvents from 1 to 10 percent, water absorption by the paper made from rice straw has decreased by approximately 93 percent. Adding royal seed gum and nettle extract has a positive effect on the diameter of the halo and has antimicrobial properties. Honey wax with 5% and 10% concentration with nano-encapsulated nettle extract with royal seed gum was selected as the most suitable coating to improve antibacterial activity.ConclusionDue to the characteristics of rice straw and the experiments shown, rice straw can be considered as a suitable alternative to oil resources in the production and usage of disposable tableware. Rice straw has the potential to be used as a cellulose source for the production of disposable containers, and honey wax with a 5% concentration and nano-encapsulated nettle extract can improve the hydrophobic and antimicrobial properties as the airtight coating of the dishes.
Research Article
N. Monjezi; M. Soleymani
Abstract
Introduction Sugarcane cultivation in Khuzestan province is in the form of planting in-furrow. Due to the fact that in a machine harvesting, the reaper is not able to fully harvest the straw in the furrow, in the planting in-furrow method, it is necessary to transfer the rows of straw to the stack. So ...
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Introduction Sugarcane cultivation in Khuzestan province is in the form of planting in-furrow. Due to the fact that in a machine harvesting, the reaper is not able to fully harvest the straw in the furrow, in the planting in-furrow method, it is necessary to transfer the rows of straw to the stack. So one of the measures at the time was hilling up operations or stacking reeds planted in the furrow. Therefore, due to the salinity of irrigation water and high groundwater levels, which have increased the salinity of sugarcane fields in Khuzestan province, planting this product in summer to protect the seedlings against salinity is mandatory in the furrow. On one hand, due to the difficulty of harvesting operations in the furrow during the harvest season, and on the other hand, because of the reduction of waste during harvesting, the plant needs to be located on the ridge. Therefore, in sugarcane fields, when the seedlings are established and grown, the furrow and ridges are replaced, and to perform this operation special machines are required. According to the study, so far there has been no scientific and reasoned report on the study and evaluation of different types of hilling up devices and different speeds in sugarcane cultivation, and the use of machines in sugarcane cultivation and industry is based solely on objective observations. Therefore, in this study, three different types of devices have been evaluated in two soil textures and three different forward speeds as a step towards choosing the best type of machine and optimal speed of hilling up operations in sugarcane cultivation.Materials and Methods The purpose of this study was to evaluate three different methods of sugarcane hilling up in two soil textures and three different forward speeds. Research treatments include: soil texture (clay loam and silty clay loam), hilling up methods (6-shanks subsoil + 10-shanks subsoil, 8-shanks subsoil + hilling up device No. 1 and 8-shanks subsoil + hilling up device No. 2), and forward speeds (5, 6, and 7 kilometers per hour). Design of a factorial experiment based on randomized complete block design with three replications in Amirkabir field 208 (ALC 200 field 8) with clay loam texture and cultivar CP69-1062 and farm ARC14-22 with silty clay loam texture and cultivar CP69-1062, 15% moisture, and first-year cultivation was performed. The test plot includes 108 furrows. The area of each plot was two furrows. The length of each furrow was 250 meters (equal to the length of the sugarcane rows). To avoid affecting the interactions of the treatments, a distance was given between the treatments. The farms being tested were newly cultivated farms. The surface of the farm was furrowed and ridged. Care was taken in selecting the farm so that the humidity was similar in its different sections. After setting the right time for the hilling up and before starting the operation, soil sampling is required to determine the soil cone index and soil moisture. The physical properties of this study include Mean Weight Diameter (MWD), bulk density, soil surface uniformity, soil water permeability, and furrow depth (stack height). Analysis of variance and Duncan test were used to compare the treatments using SAS 9.4 software.Results and Discussion The results showed that there was a significant difference between soil Mean Weight Diameter, bulk density, soil surface uniformity, and soil water permeability in soil texture treatments, type of hilling up machine, and forward speed. Furrow depth index (stack height) was significantly different in treatments of type of machine and forward speed but not in soil texture treatments. The comparison of means showed that the whole loam texture treatment had 6-shanks + 10-shanks at a speed of 7 km h-1 with the smallest mean weight diameter (16.06 mm). The use of 6-shanks subsoil + 10-shanks subsoil in hilling up in whole texture and speed of 5 km h-1 significantly reduced soil bulk density. The lowest coefficient of variation of soil surface uniformity was obtained with 8-shanks subsoil + hilling up device No. 1 in clay loam texture and 7 km h-1 forward speed. The highest rate of water permeability in the soil was obtained after the hilling up operation with 6-shanks subsoil + 10-shanks subsoil in a total texture of 2.32 cm h-1. Furrow depth index (stack height) was also within the acceptable range (10-15 cm) in all treatments. But in addition to height, the appearance of the ridges is also important. In the treatment of 6-shanks + 10-shanks in plant stacking and embankment operations, sometimes in fields, there are parts where this operation is not done well and the machine is not capable enough and is in the middle of the created ridges. Harvesting operations do not cause proper reed flooring. Therefore, to solve this problem, it is necessary to perform the hilling up operation at the appropriate speed and humidity so that the soil is well placed on the rows of reeds and the proper appearance of the ridge is maintained.Conclusion In this study, three different types of devices have been evaluated in two soil textures and three different forward speeds as a step towards choosing the best type of machine and optimal speed of hilling up operations in sugarcane cultivation. The physical properties of the soil, including the soil Mean Weight Diameter, bulk density, soil surface uniformity, soil water permeability, and the size of the furrow depth (ridge height) were measured, and the best treatments were identified. Considering the importance of hilling up operations in sugarcane cultivation and to complete the results of this experiment, the following items that could not be studied in this study are suggested. The effect of using different methods on hilling up should be investigated on the yield of sugarcane. The effect of using different devices on hilling up in terms of tensile strength, work efficiency, and time required to do the work, fuel consumption, cost of timely work, and maintenance costs in operations on sugarcane hilling up should be investigated.
Research Article
B. Rahmati nejad; M. Abbasgholipour; B. Mohammadi Alasti
Abstract
IntroductionMore than 30% of the heat energy generated by the engine is transferred by the cooling system. If this heat transfer is not accomplished properly, then the engine heat will increase and it will wear the parts by removing oil film between the pieces. A cooling system is used to remove this ...
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IntroductionMore than 30% of the heat energy generated by the engine is transferred by the cooling system. If this heat transfer is not accomplished properly, then the engine heat will increase and it will wear the parts by removing oil film between the pieces. A cooling system is used to remove this heat. The radiator is an important component of this system. Increasing heat transfer in the car engine by the cooling system is possible by using two methods of changing the radiator geometry and optimizing it and using fluids with high thermal properties. In this research, we investigated the improvement of radiator thermal performance using nanofluids using a laboratory model. The effect of nanoparticle volume fraction and cooling flow rate on heat transfer rate, and heat transfer coefficient was investigated.Materials and MethodsIn this research, a laboratory model was designed and manufactured to evaluate the thermal performance of the MF 285 tractor radiator using nanofluid. In this laboratory model, water was combined and used as a base fluid with nanoparticles AL2O3. 20 nm nanoparticles with volume percentages of 1 to 4% were used. An electric stirrer and magnetic stirrer were used to prepare the nanofluid. For the produced fluid to be usable, add SDBS surfactant to it. The temperature of the inlet fluid to the radiator was 85 °C and the cooling fluid flow rate was 3.18 to 15.08 (lit. min-1 )) and the airflow rate was 3.2 to 6.4 (m s-1). Two T-type thermocouples are installed to measure the inlet and outlet temperature of the radiator and two other front and rear fans to measure the inlet and outlet air temperature and four more are installed on the radiator to measure the radiator body temperature.Results and DiscussionThe results show that in nanofluid with a 4% volume fraction compared to a 1% volume fraction, it can be seen an increase of 8.7% in density, 7.7% in viscosity, and 9.1% in thermal conductivity, and also a decrease of 8.8% in specific heat. The maximum temperature difference between the inlet and outlet sensors of the radiator when the thermostat is open and the cooling fluid flows through the radiator is 12 to 15 °C. By increasing the speed of the electromotor from 40 Hz to 50 Hz, the temperature of the water cooling fluid at the outlet part becomes 4.7 °C cooler and the air temperature at the outlet part becomes 7.3 °C warmer. As the speed of the electromotor increases, the rate of heat transfer increases. At the maximum value of airflow and cooling fluid, by adding 4% by volume of nanoparticles to the base fluid, the rate of heat transfer can be increased about 37% compared to the base fluid. Compared to water, nanofluid containing 4% by volume of AL2O3 at maximum speed has a 28% increase in heat transfer coefficient. Also, by increasing the electric motor speed from 20 Hz to 40 Hz, the heat transfer coefficient of pure water shows about 26% increase and the nanofluid shows an average of 29% increase.ConclusionIncreasing the volume fraction of nanoparticles suspended AL2O3 in the base fluid increases the density, viscosity, and thermal conductivity, which increases the heat transfer rate and reduces the outlet temperature of the radiator. The presence of nanofluid in the engine cooling system increases the heat transfer from the radiator, and despite this feature, the size and weight of the radiator can be reduced without affecting its heat transfer performance. It can also improve heat transfer performance by increasing the cooling flow rate and the airflow rate.
Research Article
Modeling
M. Dana; P. Ahmadi Moghaddam
Abstract
IntroductionToday, the development of the livestock industry and feed supply is a vital issue due to the growing world population, the importance of animal protein supply, and the growing requirement for livestock products.A porous medium refers to a solid-void (pore) space that is occupied by a fluid ...
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IntroductionToday, the development of the livestock industry and feed supply is a vital issue due to the growing world population, the importance of animal protein supply, and the growing requirement for livestock products.A porous medium refers to a solid-void (pore) space that is occupied by a fluid (gas or liquid). Generally, many of these pores are interconnected which makes the transportation of mass and heat possible through the pores and this contributes to a faster transportation process through the solid matrix. Porosity is the fraction of void space to total volume.While the pores are large enough, water vapor and air in the porous media can be transported by molecular diffusion. Molecular diffusion of a gas species (e.g., vapor) in a gas mixture (e.g., vapor and air) is described by Fick’s law.Materials and MethodsIn this study, the samples were classified into four categories, including control, 3-impacts (low conditioning), 8-impacts (average conditioning), and 13-impacts (high conditioning). Each category included six samples (50-grams) that were used to measure different characteristics at different stages. All samples were weighed every two hours using a digital scale (0.001 gr precision). The leaf-stem separation force then was extracted using a texture analyzer. All experiments were repeated three times, and finally, the mean of these three repetitions was reported as the final value for the intended parameter.The geometry of the alfalfa stem was drawn in Gambit software and after meshing and applying boundary conditions; it was transferred to ANSYS Fluent software. Then, while the solver was selected, adjusted under relaxation factors were applied. In the following, mesh independency was checked and the results were reported.Results and DiscussionTo ensure numerical accuracy, the experimental data should be validated with the simulation results. For this purpose, experimental moisture losses were compared to the software results and showed a good agreement. Then, the moisture ratio curves (kinetics of drying) and force-time chart were presented.The impact of the moisture content of the tissue was evaluated on the value of force per time. Therefore, three samples of alfalfa with different relative humidity in terms of leaf-stem separation force were reported.The results of the numerical simulations were presented as two main contours: the velocity magnitude and moisture (water vapor) mass fraction. The simulation results were provided for all different modes and compared to the experimental data. Finally, errors between both results were presented in a table.ConclusionRegarding the quality and losses of the final product and comparisons between four different modes (control, 3 impacts, 8 impacts, and 13 impacts), the mode with 8 impacts was selected as the best mode.The Force-time chart illustrated two peaks due to the special multi-layer texture of the alfalfa. Regarding reducing the moisture ratio of the alfalfa as compared to the optimal, the force required to separate the leaves from the alfalfa stem was significantly decreased. Also, a significant increase in the losses was observed for impacts modes higher than 8.
Research Article
Bioenergy
M. Eshaghi Pireh; M. Gholami Par-Shokohi; D. Mohammad Zamani
Abstract
IntroductionBiodiesel is an eco-friendly renewable alternate fuel and is made from transesterification of vegetable oils and animal fat. The use of biodiesel fuel as a strategy to conserve energy and reduce emissions is becoming increasingly important in engines. Biodiesel fuels increase NOx emissions ...
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IntroductionBiodiesel is an eco-friendly renewable alternate fuel and is made from transesterification of vegetable oils and animal fat. The use of biodiesel fuel as a strategy to conserve energy and reduce emissions is becoming increasingly important in engines. Biodiesel fuels increase NOx emissions in the engines. Compensate for the negative effect, the use of particles additive can be a reliable solution. In this study, the state of heat balance in a single-cylinder, four-stroke diesel engine with different fuel combinations with DXBYGZ formula (X % diesel fuel, Y % biodiesel mass, and Z ppm graphene oxide nanoparticles), has been studied experimentally.Materials and MethodsGraphene nanoparticles in three levels of 30, 60, and 90 ppm were mixed with biodiesel produced from cooking waste oil by transesterification method with volume percentages of 5 and 20% and pure diesel was used. The test engine was a diesel engine, single-cylinder, four-stroke, compression ignition, and water cooling, in the laboratory of renewable energies of agricultural faculty, Moghadas Ardabili University. The engine is connected to a dynamometer and data were obtained after reaching steady state conditions. In thermal balance study, the combustion process merely as a process intended to free up energy fuel, and the first law of thermodynamics is used. The energy contained in the fuel is converted to useful and losses energies by combustion. Useful energy measured by dynamometer as brake power and losses energy including exhaust emission and cooling system losses. Variance analysis of all engine energy balance was done by split-plot design based on a completely randomized design and the means were compared with each other using the Duncan test at 5% probability.Results and DiscussionThe results showed that by adding 60 ppm of graphene oxide and 20% biodiesel to diesel fuel, the useful output power is reduced to a minimum and is reduced by about 5.52%. The results of the model evaluation of useful power, exhaust emissions, and thermal losses in the cooling system showed that the exponential model had a better fit. By adding biodiesel and graphene oxide nanoparticles to diesel fuel, the useful power was reduced. In order to achieve the maximum useful output power and with the priority of adding biodiesel to a high amount, the fuel composition of D80B20G90 had relatively better conditions. By adding 30 ppm of graphene to pure diesel fuel, the equivalent power of exhaust fumes was reduced to a minimum of about 18.5%. In general, heat loss through the cooling system in pure diesel fuel (D100) was lower than other fuel compounds. Pure diesel fuel was recognized as the best fuel mixture due to having the highest useful power, and lowest energy losses in the form of exhaust fumes and through cooling.ConclusionBy adding graphene oxide to pure diesel fuel, the useful output power was reduced to a minimum. With the increase of biodiesel to diesel fuel, the amount of power of the cooling system also increased. By adding graphene oxide to pure diesel fuel, the equivalent power of the exhaust fumes was reduced. Heat loss through the cooling system increased with the increase of nano-graphene and biodiesel.
Research Article
Modeling
E. Aghaei Badelbou; V. Rostampour; A. Rezvanivand fanaei; A. M. Nikbakht
Abstract
IntroductionCyclone separators use the centrifugal force generated by the gas flow stream to separate the particles from their carrier gas. Simple design, low capital, and easy maintenance make them ideal for use as a valuable pre-refining or sedimentation device. The cause of the particles moving towards ...
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IntroductionCyclone separators use the centrifugal force generated by the gas flow stream to separate the particles from their carrier gas. Simple design, low capital, and easy maintenance make them ideal for use as a valuable pre-refining or sedimentation device. The cause of the particles moving towards the wall and separating from the fluid phase is the centrifugal force created by the rotational flow in a cyclone.Computational fluid dynamics (CFD) is one of the most well-known and widely used advanced modeling methods used for a variety of applications, including separation processes, thermal processes such as dryers, as well as a wide range of engineering and agricultural applications. The numerical solution of Navier-Stokes equations is the basis of all CFD techniques, which is the result of the rapid progress of computers and a deep understanding of the numerical solution of turbulence phenomena.Materials and MethodsThe measurement system of experimental data includes a cyclone separator, feeder, piping, and fan. Measurements of velocity and pressure were carried out using a hot wire air flow rate, (Model 8465-TSI with a resolution of 0.07 m.s-1 and a working range of 0.125 to 150 m.s-1), as well as a differential pressure gauge (CPE310s- KIMO, with an accuracy of 0.1 Pa), respectively. To investigate the effect of the output flow regulator plate on the cyclone performance, five different positions in addition to the base position (zero degree angle or fully open) including angles of 15, 30, 45, 60, and 75 degrees were evaluated.The conservation laws governing the various flows and geometries in the CFD include the conservation law of mass, conservation law of momentum, and conservation law of energy.According to the Mach number value, the pressure base solver was selected. Also, the Reynolds stress model (RSM) was applied to model the flow turbulence. In the discrete phase model (DPM), the fluid phase is solved continuously by solving averaged time equations, while the dispersed phase is calculated by tracing a large number of particles through the flow field.The boundary conditions used in this study include the inlet velocity boundary condition at the inlet of the cyclone, the outlet pressure boundary condition in the upper and lower outlet sections, and the non-slip wall boundary condition for other surfaces. The particle collision to the wall was also defined as reflective. In the mesh section of the cyclone simulation, five mesh levels were used to check the mesh independence test. The numbers of mesh cells in the five levels were 196810, 283120, 427890, 634940, and 1045290. The selected mesh was 427890 level regarding time consideration.Results and DiscussionIn the first section, the validation of simulation results with experimental results is discussed. The value of the velocity magnitude decreased with increasing the angle of the plate, which is probably due to the reduction of the inlet level as well as the reduction of the exhaust airflow in the cyclone air outlet.The maximum value of velocity magnitude occurred according to the direction of the air inlet in the cyclone inlet, which is gradually reduced due to the rotational motion inside the cyclone.The collection efficiency in the cyclone at different levels of regulating plate has values of 85.1% to 95.3%, with maximum collection efficiency at 30° which was 95.3%. The turbulent intensity contours show that turbulence intensity decreases to an angle of 30°, and then reaches an almost constant value for the 30, 45, and 60° angles.ConclusionAs the angle of the output current regulator plate increased, the magnitude of velocity decreased significantly.The separation efficiency showed an increasing-decreasing trend for different values of the regulator plate such that up to a 30° angle of the plate had a positive effect on the separation efficiency.In general, considering the compromise between separation efficiency and pressure drop as two key parameters affecting the performance of the cyclone, an angle of 30 degrees was selected as the best angle among the studied angles for application.
Research Article
B. Sabahi; H. Bahrami; M. J. Sheikhdavoodi; S. M. Safieddin Ardebili; E. Houshyar
Abstract
IntroductionToday, diesel engines provide the main power source for the world equipment e.g., common propulsion generators in industry and agriculture. These engines are widely used due to their high combustion efficiency, reliability, compatibility, and cost-effectiveness. However, diesel engines are ...
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IntroductionToday, diesel engines provide the main power source for the world equipment e.g., common propulsion generators in industry and agriculture. These engines are widely used due to their high combustion efficiency, reliability, compatibility, and cost-effectiveness. However, diesel engines are one of the most critical consumers of fuel which in turn causes some environmental pollution. One of the convenient and low-cost ways to reduce the pollution of these engines is dual-fuel mode and the use of gaseous fuels as an alternative fuel. This study investigated the effect of blending CNG and LPG with neat diesel in dual-fuel mode. Besides, the variation in engine coolant temperature on engine performance characteristics was experimentally studied.Materials and MethodsThe experimental apparatus consisted of a stationary, four-stroke, naturally aspirated, water-cooled, single-cylinder compression ignition engine. To control the engine load, an electrical dynamometer was made using a 7.5 kW three-phase generator and coupled to the engine as a cradle. A load cell was used to determine the force applied to the generator. The engine speed was monitored continuously by a tachometer. Fuel consumption was measured by using a weight method. A thermostat with variable temperature was used to control the temperature of the engine coolant. To measure the mass flow of air entering the cylinder, an airbox with a sharp edge orifice was used. For this study, factorial experiments in the form of a randomized complete block design with three replications were utilized to analyze the data statistically. The studied parameters were three levels of fuel ratio (100% diesel, 20% diesel and 80%± 2% CNG, 20% diesel and 80%±2% LPG), 11 engine speeds (1500 to 1600 rpm with 10 rpm intervals), and three engine coolant temperatures (50, 60, and 70 °C). All experiments were conducted in the governor control mode.Results and DiscussionThe results showed that the torque, brake power and brake mean effective pressure (BMEP) in the diesel-CNG mode at all engine speeds and in the diesel-LPG mode at low engine speeds significantly increased compared to pure diesel. The increases in these parameters in the diesel-CNG mode were 18.67%, 19.56% and 19.85%, and in the diesel-LPG mode were 14.02%, 13.86% and 14.2%, compared to those related to the pure diesel, respectively. This increase could be due to the high calorific value of gas fuels and improvement of combustion inside the cylinder due to the formation of homogeneous charge. At low engine speeds, the reductions in the brake specific fuel consumption (BSFC) and brake specific energy consumption (BSEC) for coolant temperature 60 °C were 11.21% and 10.77%, compared to coolant temperature 50 °C, respectively. Also, the BSFC and BSEC for diesel-CNG dual-fuel mode decreased by 8.12% and 10.81%, respectively. These values for the diesel-LPG dual-fuel mode were 5.4% and 2.4%, respectively. The brake thermal efficiency (BTE) also showed a significant increase at high speeds and when using the dual-fuel operational mode. However, raising the coolant temperature due to reducing the heat losses of the engine increased the BTE. The increases in BTE for coolant temperatures 60 and 70 °C were 7.19% and 4.37%, compared to the coolant temperature of 50 °C, respectively. When using the engine in dual-fuel mode, the volumetric efficiency due to reducing the air ratio showed a significant reduction. These diesel-CNG and diesel-LPG dual-fuel mode values were 20.31% and 24%, respectively. Furthermore, raising the coolant temperature diminished the volumetric efficiency. The reduction in volumetric efficiency for the coolant temperatures of 60 °C and 70 °C were 6.84% and 19.91% compared to the coolant temperature of 50 °C, respectively.ConclusionThe following conclusions can be deduced based on this study:The use of gaseous fuels as the main fuel and with a small amount of diesel in compression ignition engines is possible and improves the engine's performance characteristics.In the diesel-CNG mode, torque, brake power and BMEP at all engine speeds and in the diesel-LPG mode at low engine speeds significantly increased compared to pure diesel because of improved combustion inside the cylinder.At low engine speeds, increasing the coolant temperature reduced the BSFC and BSEC. Also, in the dual-fuel mode compared to the engine with baseline diesel fuel, the BSFC and BSEC were significantly lower due to the higher calorific value of gaseous fuels and higher power generation.The BTE at high engine speeds and when the engine was in dual-fuel mode showed a significant increase. Also, increasing the coolant temperature due to reducing the heat losses of the engine increased the BTE.When using the engine in the dual-fuel mode, due to the volume of air replaced by the gas, the volumetric efficiency showed a significant reduction. Also, raising the coolant temperature diminished the volumetric efficiency.Overall, it can be stated that the use of a diesel-CNG dual-fuel mode with a coolant temperature of 60 °C at entire engine speeds has the best outputs on the performance and combustion characteristics of the engine.
Research Article
The relationship between machine and soil
S. M. Seyedan; A. Heidari
Abstract
IntroductionSoil protection against water and wind erosion is of great importance. Since most soils of arid and semi-arid regions of Iran are poor in organic matter and continuous use of conventional tillage (moldboard plow) has increased the severity of soil organic matter depletion and degradation ...
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IntroductionSoil protection against water and wind erosion is of great importance. Since most soils of arid and semi-arid regions of Iran are poor in organic matter and continuous use of conventional tillage (moldboard plow) has increased the severity of soil organic matter depletion and degradation of soil structure. Therefore replacing conventional tillage with conservation tillage (reduced tillage and no tillage) is needed to improve soil structure and increase soil organic matter. Due to the increasing population growth and the limitation of arable land, it is necessary to remove the fallow year in dryland. Legumes are crops that can be in rotation with wheat. Materials and MethodsThis study was conducted to evaluate the effect of crop rotation and different tillage systems on rain-fed wheat farming in Kaboudarahang Township during 2012-2014. The experiment was conducted as split-plot in a randomized complete block design with three replications. In this study, different crop rotations including fallow-wheat rotation, and chickpea-wheat rotation as main plots and different tillage systems including conventional tillage (moldboard plow + power harrow), conservation tillage (chisel plow equipped with roller), conservation tillage (sweep plow equipped with roller) and direct drilling were investigated as subplots.In the economic evaluation of this project, the economic impacts of the treatments were analyzed using the partial budgeting method and the cost-benefit ratio. For this purpose, the difference between treatments income and cost compared with control treatment has been calculated and compared. The differences in the benefits of the treatments are due to the different yields of wheat. Results and DiscussionResults showed:1- The highest wheat yield in the first and second years of the study was 605.3 and 2135.1 kg ha-1, respectively in rotation of fallow wheat.2- In the first year, the highest wheat yield (690.7 kg ha-1) was related to direct planting (no tillage), but in the second year, the highest yield (2268.6 kg ha-1) was related to conservation tillage (sweep blades + roller).3- In the first and second year, the highest value of treatment was related to direct planting and conservation tillage (sweep tiller + roller), respectively.4- In the chickpea-wheat rotation, the highest net income in the first and second year was related to direct planting and conservation tillage (sweep + roller), respectively. Thebenefit-cost ratio in the conservation tillage (sweep + roller) (second year) and direct drilling (first year) methods shows that for each rial of expenses, 5.7 and 2.8 rials can be earned respectively. Therefore, economically, these tillage treatments are superior to the control treatment (conventional cultivation).5- In the wheat rotation, the highest net income in the first and second year was related to direct planting and conservation tillage (sweep + roller), respectively. The benefit-cost ratio in the conservation tillage (sweep + roller) (second year) and direct drilling (first year) methods shows that for each rial of expenses, 4.2 and 1.3 rials can be earned respectively. Therefore, it is economically justified and these tillage treatments are superior to the control treatment (conventional tillage).ConclusionThe results of this study showed that in the first and second years, economically the direct method and the conservation tillage treatment (sweep blades + roller) were superior to the conventional method, respectively. Therefore, conservation tillage methods can be replaced by the conventional method (plowing with moldboard plow) in dryland farming. Also, in dry years, direct cultivation (no tillage) is a good and economical method.
Research Article
Modeling
A. Rezvanivand fanaei; A. Hasanpour; A. M. Nikbakht
Abstract
IntroductionThermo-compressors or ejectors are used to enhance the vapor enthalpy in the process industry. The low costs of construction and maintenance, and simple structure, have increased by using this equipment in relevant fields of industry and agriculture. The thermo-compressor's inlet parameters, ...
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IntroductionThermo-compressors or ejectors are used to enhance the vapor enthalpy in the process industry. The low costs of construction and maintenance, and simple structure, have increased by using this equipment in relevant fields of industry and agriculture. The thermo-compressor's inlet parameters, including the thermodynamic properties of the motive steam and suction vapor, are the foremost affecting factor of a thermo-compressor.The steam used in processing factories loses its capability after passing through evaporators due to the reduction of pressure and temperature, gets cooled again, and returns to the boiler despite having a moderate energy level. Therefore, the use of vapor-recovery equipment can increase the efficiency of energy systems. That will lead to a significant reduction in greenhouse gas emissions and harmful environmental effects, which increase the lifetime of energy resources.Materials and MethodsThe realizable k-ε turbulence model is used to simulate turbulence within the flow. The thermo-compressor geometry has meshed in 2D and 3D modes to apply the conservation laws. For this purpose, quadratic (quad) and hexahedral (hex) types are used for two and three-dimensional meshing, respectively. Structured meshes have a high ability to obtain numerical results due to creation of structural meshes in the flow direction.The axisymmetric structure of the thermo-compressor leads to a half simulation of geometry. The thermodynamic properties of the input flows and their variations in the output, such as pressure, velocity, Mach number, and mass ratios for different motive steam pressure are extracted and discussed.Results and DiscussionDifferent levels of meshes are examined to investigate the mesh-independence test. In axisymmetric two-dimensional analysis, these levels include 33460, 51340, 78620, and 103590 cells, respectively. The relatively insignificant difference in motive flow for the third and fourth mesh levels (which proves less than 5%) clearly shows the independence of the results from the mesh size. Regarding the time considerations, the grid with 78,620 meshes was used in the simulations.The experimental data from the article by Sriveerakul et al. (2007) are used to validate the numerical results of the present work. Validation shows that the results obtained from the simulations are in good agreement with the experimental data. Since the final results of the two-dimensional analysis are very close to the three-dimensional one, the first one is selected due to the time considerations and higher computational costs of the three-dimensional mesh analysis.Considering the problem conditions, pressures of 10 and 15 bars are appropriate for practical application. Since the 15 bar motive stem creates a longer development length in the diffuser section, it is a better choice. At this level (15 bar), the temperature field within the thermo-compressor is well distributed in the presence of ideal temperature conditions. The ideal velocity distribution within the thermo-compressor and the uniformity of the motive and suction flows indicate the high performance of the thermo-compressor in these operating conditions. Applying the motive steam of 15 bars, the values of 0.59 and 0.41 for the motive and suction mass ratios of the diffuser output were achieved, respectively.ConclusionGeometrically, the study was examined in asymmetrical two-dimension and three-dimension. It was observed that there is a slight difference between the two analysis modes by comparing the velocities along the longitudinal line of the thermo-compressor. Therefore, to save computational and time costs, results are presented for the axisymmetric two-dimensional mode.The effect of 4 levels of motive steam pressure on the thermodynamic properties within the computational domain, including pressure, temperature, velocity, Mach number, mass ratios of both motive steam, and suction vapor are evaluated. Finally, the values of the performance curve for steam with motive pressures of 3.7, 5, 10, and 15 bars are presented.
Research Article
Post-harvest technologies
A. Ramezani Boukat; H. Navid; M. J. Musevi Niya; S. Ranjbar
Abstract
Introduction Transportation of fresh fruit and vegetables is complicated because it can be affected by various factors. Truck vibration is one of the most prevalent causes of mechanical damage to fresh fruit during transportation. Poor driving performance, road features, package features, truck features, ...
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Introduction Transportation of fresh fruit and vegetables is complicated because it can be affected by various factors. Truck vibration is one of the most prevalent causes of mechanical damage to fresh fruit during transportation. Poor driving performance, road features, package features, truck features, package location, and fruit features are the main factors that affect truck vibration. After the harvest, the crop's quality can be maintained and cannot be improved. Thus, the globalization of fresh produce trade needs better long-distance transportation systems to deliver high-quality products to the consumer. Fruit packaging is an essential factor in reducing the mechanical damages caused by transportation. A wide-ranging of distribution environments could affect designing packages. Accurate information about the traffic and transportation status of any region helps packaging designers to produce a more precise simulation of the existing conditions. Thus, this research was conducted to analyze the vibration levels for truck transport on highway roads using multi-sensor-based computing on packaged fruit in Iran.Materials and Methods Towards this goal, a wireless sensor network (WSN) made of three sensor nodes with tri-axial accelerometers was designed to measure the vibration levels of a truck equipped with leaf-spring suspension on highway roads. This WSN solution enabled the sensors to be easily mounted at different locations and provided real-time data monitoring. A GPS receiver and a laptop were used to determine the location of the truck, and data analysis, receptively. To analyze the vibration data a, power spectral density function (PSD) levels were applied. A PSD function shows the strength of the variations (energy) as a function of frequency. Broadly, it shows at which frequencies variations are strong and weak. The vibration levels measurement was carried out on three trucks with leaf-spring suspension. The three selected routes represent different roads type in Iran. The reason for sampling the data acquired in the long route was to obtain information from different geographical locations on the country's roads.Results and Discussion The acquired data can be used in laboratory vibration tests if it is independent of the fruit type. Because the acceleration of the truck bed, unlike the one in top rows, does not depend on the fruit type and the acceleration at the end of the truck is higher than at the front, the current study focused on the vibration at the end of the truck bed. Compared to the ASTM 4728 standard, the PSD levels of the truck on highway roads were higher from 1 to 35 Hz and lower from 35 to 200 Hz. The average RMSG values calculated for lateral, longitudinal and vertical directions of heavy trucks were 0.406, 0.236, and 0.654 G, respectively. For trucks with spring suspension, the highest PSD values occurred at frequencies below 6 Hz, and the frequency range of 3-4 Hz was determined as the dominant frequency. Comparing the average RMSG (0.654 G) found with the ones mentioned in previous studies showed that the vertical vibration levels of the truck in Iran are higher than in most countries. Apart from driving quality, these results can be explained by the type of suspension system, amount of load, and road quality.Conclusion In sum, the results can be used to simulate the truck transport conditions by programmable vibration simulators to reproduce the vibration conditions for package testing on Iran roads. The findings are highly interested in improving packaging design, reducing fruit damage, maintaining shelf life, smart transportation, and related industries. Thus, potential future works are lab simulations, optimizations of packages, and the development of a real-time vibration monitoring system.
Research Article
Bioenergy
M. Kamali; R. Abdi; A. Rohani; Sh. Abdollahpour; S. Ebrahimi
Abstract
IntroductionSince 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 ...
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IntroductionSince 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 MethodsIn 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 DiscussionThe 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.ConclusionIn 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.
Review Article
Agricultural systems engineering (greenhouse, fish farming, mushroom production)
M. Zangeneh; N. Banaeian
Abstract
IntroductionSo 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 ...
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IntroductionSo 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 MethodsIn 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 DiscussionThe 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.ConclusionTo 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.
