فهرست مطالب امید رضا روستاپور ∗

Iran has a high potential of solar radiation and lots of sunny days (more than 300 days) in a year.  In this study the feasibility of establishment the photovoltaic powerhouse in several agricultural research stations of Markazi, Esfahan and Kerman Provinces was investigated. In this regard, after determining and analyzing the required meteorological information using Meteonorm software and system simulation by PVsys software, economic analysis of each station were performed by determining the breakeven point and the average cost of energy production for different discount rates. The study also examined the reduction of pollution due to the reduction of Cox, Nox and Sox emissions as a result of employing photovoltaic power plants. According to the results, the most solar electricity generation was occurred in Rudasht station of Esfahan province equaled to 303 kWh/m2 per a year. Photovoltaic powerhouse establishment in the research stations could eliminate pollution production up to 748 tons in a year which exhausted from fuel combustion in the power generation turbines. Results also illustrates considering electricity purchase tariff (6370 IRR/kWh), the construction of photovoltaic power plants with the usual interest rate (more than 8%) is not economically viable for investors. Therefore, the implementation of such projects cusses to produce clean energy and to bring environmental protection, a special banking facilities with interest rates below 8% is recommend to motivate private sector for investment.

Providing new solutions to control wet waste is one of the most important issues in maintaining public health. A good solution in order to manage of food waste for benefits of environmental, economic and agriculture is drying. Drying will reduce waste and increase preservation by reducing moisture. In this regard, two types of methods for drying food waste with conventional tray pattern, and tray with Central and lateral airflow pattern in cabinet dryer were studied. The effect of three temperatures of 50, 60 and 70 ° C and three velocities 1, 1.5 and 2 m / s with thickness of 3 cm on the energy consumption were investigated. In addition, drying kinetics and drying intensity diagrams were extracted. The results showed that the in the central and lateral airflow pattern, temperature is an important factor that affects in the drying of food waste. The energy consumption in the tray with central and lateral airflow pattern is more than the conventional tray pattern.

Rosa damascena is one of the significant Rosa flower in all over the world and one of the famous plant in horticulture history. Rosa flowers will harvest from the first of Ordibehesht to the end of Khordad before rising sun and in the cool air of morning. In the current research, a portable machine for flower harvesting designed and developed. This machine contains a cutter, suction pipe, fuel motor, frame, backpack and a cyclone separator. All components of the machine including the motor and the cyclone separator are assembled on frame and transported by workers. Flower cut exactly under the receptacle by a reciprocating cutter and sucked to the flexible pipe by the fuel motor and after that transferred to a cyclone separator. Finally, flower is collected in a canvas bag installed at the end of cyclone. Evaluation of the machine was done using completely randomized design with three treatments and three replications in the flower plain of Lizangan from Darab. The treatments were the revolution of motor shaft in three levels of 900, 1200 and 1500 rpm. The parameters including fuel consumption and harvesting period time in every treatment were measured. The control treatment was considered traditional flower harvesting by hand. Based on the evaluation results, increasing the rpm of motor was caused to increase fuel consumption and decrease the net harvesting period time. Also, harvesting time at maximum revolution of motor was decreased in comparison with hand harvesting.

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.

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.

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.

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.

There are many losses in crop production each year, due to various reasons. The use of shadow nets in orchards is one of the protection solutions. In order to select the appropriate net, it is necessary to determine the main factors in plant growth to utilize from net benefits and prevent its adverse effects.. In general, light, temperature and humidity are three main effective factors in plant growth and development. In this research, a monitoring system was designed and built to monitor the changes in radiation, temperature and relative humidity inside and outside of the selected covered pistachio and apricot gardens. Wind velocity and direction outside the gardens were also measured. The measured data by the system related to these factors inside and outside the gardens was collected in a central server. Investigation of monthly graphs of changes in temperature, relative humidity and light received from apricot gardens in Shahroud and Pistachio gardens in Rafsanjan showed that the temperature inside the shading nets was lower than outside but there was no significant difference between the months records. For relative humidity and light factors, respectively the inside records were higher and lower than outside records. But no significant differences were observed between the months. In general, the study of changes in the mean values of the three factors of temperature, humidity and radiation in the whole period showed that the greatest effect of shading net in orchards was the reducing of the intensity of light received. When the wind velocity was high, the temperature inside and outside the shading net was closer to each other.

Drying process is not uniform in the common rice dryers (batch type dryers). In order to decrease this problem, two types of passing hot air dryer consisted of the lateral and central patterns has been defined and method of air distribution in the rice porous media modeled by Fluent software in transient condition. In the lateral pattern, air enters through the side walls of the dryer chamber and in the central pattern, air enters through the central channel of the dryer chamber. The air temperature is 40 oc and air flow rate is 550 m3/h in all models. The results of simulation illustrate, the air flows more rapidly in the central pattern and penetrates into all parts of the dryer chamber. There is not any central passing air channel in the lateral pattern so, it caused to produce an irregular temperature field with high distortion. Models were verified in steady state condition. Results show the final temperature of model was near the measured data with 2% deviation.

Long drying time and high energy consumption are the big problems in paddy drying using conventional batch type dryer. Besides, non-uniformity occurs in paddy rice dried and low milling quality. Paddy is over dried in lower layers and broken kernel chance increased in milling process. Using of a new pattern for warm air causes to better air passing through the paddy bulk and uniformity of drying. Computational fluid dynamics (CFD) is a good method for modeling of air passing in dryers in order to find better air condition in paddy drying process. The aim of this research was investigation on common and porch patterns applied for air entrance to paddy bulk in a dryer in order to optimize air channel conditions in a conventional paddy dryer. In this study, optimization of air flow was investigated in a batch type paddy dryer using computational fluid dynamics (CFD). Two patterns as conventional and porch (reverse V type) patterns were applied for air entrance to paddy bulk in the dryer as conventional and porch (reverse V type) patterns. Experimental examination were done using a laboratory batch type dryer with chargeable air flow pattern in 50 °C for drying paddy (Tarom-Hashmei Var.). Numerical simulation of air velocity and pressure drop in porous media of paddy in the dryer was achieved by employing computational fluid dynamics method and Fluent software. Air velocity pattern and temperature changes in bulk of paddy were investigated in different time of solution including 20, 100, 1000, 1800, 3600 and 7200 seconds for both patterns. Considering air flow and temperature as constant, the results showed the porch type pattern has better performance than the conventional pattern for air passing in the dryer. The velocity vortex was higher in all parts of the channel in the porch scheme. Air velocity uniformed decreased from beginning to end area in the conventional pattern, but in the porch type pattern, air velocity was more in the end of the duct than beginning area. Pressure drop was about 10 percent in the conventional pattern than porch pattern. At the end of the air channel, this variation inversed due to contact of the air with the end wall and pressure drop in this part of the chamber of porch scheme was higher than the conventional one. Improvement of air flow in paddy occurred in low and middle layers in the porch type pattern and there was no difference between two air passing patterns in top layers. Validation of modeling showed that temperature disturbance of the porch model was more uniform than the conventional model and difference between temperatures of model and experiments was about 2 to 3 °C. The research concluded that using of the porch type pattern had better performance than the conventional pattern for air passing in the dryer but it is needs to more supplementary research to find the best height and angle in the paddy dryer. Porch type pattern causes to more speed and uniformity of air among of paddy than the conventional pattern. This improvement observed in low and middle layers of the paddy bulk. Validation of temperature data showed that the difference between experimental and modeled data was 4 to 6 percent and this difference was higher in the conventional pattern than the porch pattern. According to the results of this research, Porch pattern can be recommended to use in the conventional batch type dryer.

The main problems of dried figs are the decrease of its quality due to activity of the harmful microorganism, the production aflatoxin B1 and pest by some insects, such as Plodia, so proper processing operations on this product are necessary. In this research, the ability to produce fig concentrate powder using spray dryer was investigated. The experiment was carried out in two steps. In the first stage, the effect of different levels of maltodextrin (three levels of 30, 40 and 50%) and silicon dioxide (two levels of 3 and 5%) on performance of dryer in powder production and optimal levels of additives was determined. In the second step, the effect of factors, temperature (two levels of 150 and 170 oC), inlet feed flow rate (two levels of 3 and 5 liters per hour) and nozzle pressure (two levels of 3 and 5 bar) in a completely randomized deign (CRD) on production performance and physical properties of fig concentrate powder were studied. The results showed that levels of 40% maltodextrin and 5% silicon dioxide had the highest effect on optimum powder production and lack of stickiness and lump (P≥0.50). In addition, it was found that the machine's performance increases with increasing inlet air temperature, increasing nozzle pressure and reducing feed flow rate. Decrease of flow rate of feed inlet and increase of the inlet air temperature and the nozzle pressure resulted in the production of a powder with lower moisture content and smaller diameter particle size (P≥0.50). It was also found that temperature, flow rate and nozzle pressure had a significant effect on powder solubility (P≥0.01). During 4 weeks of shelf life of selected powder sample (40% maltodextrin and 5% silicon dioxide, air temperature 170 °C, flow rate 3 liters per hour and pressure 5 bar) the values of color factors L*, a* and b* decreased 18, 9.1 and 9.41%, respectively.

Pistachio plays an important role as exportation of Iran. The method of drying process has a remarkable influence on the quality of dried products. There are various methods for drying pistachio; however, choosing a suitable method of drying depends on reliability, healthiness and rapids. In current research, the effect of temperature in three levels of 40, 50 and 60°C and rotational speed of the dryer agitator in three levels of 5, 10 and 15rpm on reduction rate of drying period and drying kinetics of a common Iranian pistachio (Kalleh Ghoochi v.), in a new intelligent- vacuum rotary dryer, was investigated. This dryer was consisted of a cylindrical chamber and a twin electrical heater which dried products in a vacuum medium. The experimental data was analyzed in a statistical software "SPSS 10 " In accordance with the results, temperature and rotational speed of the agitator had a significant effect on drying period. When temperature and speed were 60°C and 15rpm respectively, drying period was short and equaled 185 min, but in temperature of 40°C and speed of 5rpm, drying period was long and equaled 325 min. Increasing the temperature also increased the rate of drying significantly. Results indicated that increasing temperature from 40°C to 50°C caused 25% decrease in the drying period and increasing temperature from 40°C to 60°C caused 39% decrease in drying period.

A mixed solar dryer with a specific mechanism to vary the tilted angle of collector، is utilized to fulfill all tests. The efficiency of the dryers is low because of various reasons such as heat loss of air in an open flow circuit. Getting air back toward the air inlet of dryer can increase the efficiency of dryer and decrease drying process period. A new mechanism considered for dryer which controls the percentage of air recirculation. It contains two dampers which embedded in return air channel of dryer. In order to investigate the effect of air recirculation on energy consumption of drying and dryer efficiency، thin layer of tomato slices are dried in three levels of air flow rate (0. 018، 0. 036 and 0. 054 m3/s) and four levels of air recirculation percentage (0، 50، 75 and 87. 5%). Total experiments were achieved in the beginning of autumn season to reach the moisture content of 12% (w. b) of the samples. The results illustrated the minimum of energy consumption and the maximum of efficiency was provided when 75% of air flow was got back to the inlet of dryer.

Potato (Solanum tuberosum) is one of the most important agriculture products which damage soon because of inappropriate storage and processing conditions. Drying process causes to increase the shelf life of potato. In current research, potato slices dried in a parallel flow dryer and its kinetics of drying and shrinkage was studied. The experiments were accomplished in three levels of slices thickness; 3, 6 and 9 mm and three levels of temperature; 50, 60 and 70 c. Air flow was considered as 0.012 m3/s in all tests. Drying rate, moisture reduction, variation of area and roundness of samples were investigated during drying period. Results showed the maximum drying rate has been occurred when temperature was 70 c and thickness was 3 mm. Area and roundness variation was increased while temperature increased and thickness decreased.

Concentration decreases the amount of water in liquid food and increases shelf life. Several types of evaporators are used for concentration, thus, it is necessary to simulate the process before design to control efficiency. The flow of pomegranate juice was simulated in a forward-feed flat plate evaporator at concentrations of 18 to 50 Brix in a two-phase mixture model using computational fluid dynamics. The results show that a vacuum developed in the evaporator column causing a slight drop in pressure at the inlet. Temperature increased at high intensities at the flow entrance zone. The magnitude of the velocity of the vapor increased as the flow increased from the inlet toward the outlet of the evaporator. Radial velocity was at a maximum in the middle of the flow medium and decreased gradually toward the boundary layer. The volume fraction of the pomegranate juice decreased and the volume fraction of the steam increased gradually from the inlet toward the outlet of the evaporator. This model can be applied for other liquids, but it is first necessary to define the thermo-physical properties of the liquid at different concentrations.

Determination of thermo-physical properties of pomegranate juice is necessary to control processes such as drying and concentration. These properties have been affected by soluble solid content and temperature. Therefore the properties including; density، specific heat and thermal conductivity were determined at three levels of soluble solid content، 12o، 40o and 65o Brix and temperature range from 25 to 70 oC. Thermal conductivity by co-axial cylinder apparatus، specific heat by differential scanning calorimeter and density by a volumetric pycnometer were measured. Regression analysis indicated that both soluble solid content and temperature affected on these properties but the soluble solid content has more influence. Increase of soluble solid content from 12 to 65 caused a decrease in thermal conductivity from 0. 233 to 0. 193 W/m. oC، specific heat from 5. 19 to 3. 34 kJ/kg. oC and an increase in density from 1027 to 1323 kg/m3 respectively. With increase in temperature from 30 to 70 oC، density decrease from 1173 to 1150 kg/m3 but thermal conductivity increase from 0. 188 to 0. 229 W/m. oC during temperature increasing from 28 to 42 oC and specific heat increase from 3. 9 to 4. 4 kJ/kg during temperature increasing from 40 to 60 oC. With regression analysis، the suitable empirical models of thermophysical properties of pomegranate juice with operating variables were obtained.