نشریه مکانیزاسیون کشاورزی
سال ششم شماره 3 (پاییز 1400)

Bread is one of the main categories of food in Iran that supply daily calorie, protein. Lavash flatbread consisted about 34% of total flatbreads produced in Iran. Large quantities of bread are wasted every year because bread production technology and baking methods. The main objective of this study was to evaluate the flatbread quality produced by the developed bread baking machine with an indirect heating system and the existing conventional machines with a direct heating system. Bread baking experiments were conducted and the instrumental, sensory, and staling characteristics of the produced flatbreads was evaluated. The effect of baking methods and storage time on the quality of bread was significant and the bread produced with the indirect heating system had higher rating compared to the bread produced from the conventional industrial machines with direct heating and its shelf life was longer. In the indirect heating machine, there was acceptable uniformity on the baking bed as view point of heat distribution and baking uniformity. The variation of puncher force of 10 mm probe in the 5 layers of bread indicated that the surface firmness of bread increased after 48 h of storage. In addition, in the first days of storage, no differences was observed in the puncher force of bread produced by two machines but during the storage, the firmness of breads produced by indirect heating machine was lower as compared with direct heating machine. Also, bread prepared using the new machine was free of any contaminants such as PAHs.

Soil compaction increase is one of the main threats to agricultural soil structure, which may even lead to soil decomposition. In order to prevent the phenomenon of soil compaction, knowing the mechanical properties of soil is important in the determination of the allowable stress limits. Pre-compaction stress, as the maximum stress that soil can withstand without increasing its compaction, is one of the most important mechanical properties of soil. The plate sinkage test is a suitable method for determining the soil pre-compaction stress. In this research, the experimental test of plate deposition on a sample of arable soil (loamy sandy loam) at the moisture content of 15% d.b. with density of 1500 kg.m3 was performed and the soil mechanical properties were determined. Then, the plate sitting test was performed in twodimensional and symmetrical methods by finite element method and Drucker Prager model in Abaqus software and precompression stress was predicted by this method. Stress distribution and displacement in the soil depth layers were also analyzed. The results showed that the Drucker-Prager model with a 99% explanation coefficient was in good agreement with the data obtained from the experiments. Examination of compressive stress and displacement in different layers in the soil depth showed that the amount of stress and displacement in the layers close to the load surface was higher than that for the lower layers.

Multiphase flow systems are important parts of industrial processes, including the food, pharmaceutical, oil and petrochemical industries and also agriculture. In order to monitor and control these systems, it is necessary to determine its characteristics such as mass flow of materials, mass concentration, volumetric concentration, density, velocity and homogeneity distribution of fluid. Magnetic induction tomography is one of the new methods of monitoring fluid in pipelines. Its main advantage is that MIT sensors have no contact with the fluid flow. In this research, design and performance simulation of applied current magnetic induction tomography (AC-MIT) system was studied. The system included two annular electrodes as a transmitter sensor and 196 coils as a receiver sensor. In order to performance simulation of the system, three positions (R=0, R=0.35, R=0.65) were considered for the target object and the image reconstructed using Landweber iterative algorithm with Tikhonov regularization method. To evaluate the quality of the reconstructed image, size error (SE) and root mean square error (RMSE) were calculated in different regularization coefficients. The results showed that RMSE increases with increasing regularization coefficient and decreases when the target object approaches the cross-sectional wall. SE parameter decreases as the target object approaches the cross-sectional wall. The minimum and maximum values of the calculated SE were related to R=0.65 and middle position, equal to 0.13 % and 5.72%, respectively.

The growth of livestock production and the development of livestock farms increases the production of by-products, including livestock waste, which leads to destructive environmental effects. Paying attention to waste management methods has a beneficial effect in reducing the amount of environmental effects. The present study was performed by practical data collection from 4 farms with different methods of waste disposal. The tables and recommendations of the Intergovernmental Panel on Climate Change (IPCC) were used to estimate emissions levels. The obtained data were processed with Simapro software to calculate the environmental indicators of disposal methods. Based on the results, in the management method of waste collection in lagoon, the final environmental index was the lowest as 0.706 per ton of waste. In the depot method for dry mass and using part of it as animal bed, the obtained index was the highest with 1.379. Among the environmental effects and indicators, the effect of the global warming group in all farms was greater than the effect of other groups. Despite the high production of methane in the storage method in the lagoon, due to the production of nitrous oxide gas in the drying method and especially the use of dry waste in the animal bed, these methods had a greater effect of global warming. By managing waste through anaerobic digestion and methane collection, environmental effects can be reduced and energy benefits can be used.

In this study, the effects of freeze and hot air dryings on aroma, vitamin C content and color change of orange slices were studied. The freeze dryer was drying at -50 °C and the hot air dryer at 60 °C. The results showed that the freeze dryer maintained the color quality and aroma of the dried slices similar to the fresh orange slices (fresh oranges L*=48.79, a*=-3.17 and b*=44.25 and freeze dried L*=82.26, a*=-2.71 and b*=50.68) but in the case of hot air dryer, the color quality decreased and browning was occurred (L*=58.09, a*=10.78 and b*=45.51). The highest response of olfactory sensors in fresh orange, freeze dried and hot air dried slices were MQ9, MQ7, and MQ3, respectively, and the lowest response of olfactory sensors in all three slices was MQ6. The biggest difference between the sensors' response was the change in the product's aroma during drying process. The amount of vitamin C in two methods of freezer drying (902.4 mg / 100g) and hot air drying (956.6 mg / 100g) decreased compared to fresh orange slices (1001.3mg / 100g). According to the measured Vitamin C contents, in hot air dried slices the concentration of Vitamin C was higher than that for freeze dried slices.

In this study, the application of a solar system for heating a greenhouse of twin type with arched structure and single layer polyethylene coating was investigated. For this purpose, initially, the heating needs of the greenhouse were determined. Then, according to the obtained results, a flat-panel solar water heater with a collector of 6 square meters and a tank volume of 500 liters was selected and installed next to the greenhouse cucumber production unit to heat the air inside the greenhouse with 4 unit of 10-blade aluminum radiators. Then, using paired t-test, the results obtained in this greenhouse were compared with the conventional type in the area that had a diesel heater. The results showed that in terms of carbon dioxide, average temperature and relative humidity, there was no significant difference between the two greenhouses, but in terms of chlorophyll index and crop yield, there was a significant difference between the two greenhouses, at a probability level of 1 and 5 percent, respectively. Diesel had a higher average in these factors. Also, managing the four factors of minimum temperature, average temperature, chlorophyll content and maximum relative humidity in the greenhouse equipped with solar water heater and controlling the two factors of minimum temperature and chlorophyll content in the greenhouse equipped with diesel heater can improve photosynthesis and increase yield.

Approximately three-quarters of harvested tomatoes are freshly used. Good quality is an important factor in distributing of fresh tomato. Chlorophyll is the green chemicals to provide required food of plants and ensure plant growth and productivity. The main function of chlorophyll is to absorb blue and red lights and perform photosynthesis. In recent years, the tendency to use of prediction methods such as soft computing and artificial intelligence for growth of plans has increased. The main aim of this study was to investigate the relationship between height and chlorophyll content in the leaves of tomato plants using modeling and predicting techniques and compare the accuracy of these methods. In this study, some cultivated plants of tomato were randomly selected for height and SPAD measurements. The results showed the relationship between Chlorophyll content and height of plants was very low (R2 = 0.276). However using the modelling of ANN and ANFIS improved the prediction power up to (R2=0.982 and 0.913), respectively.

The study presents the statistical analysis of wind data in Broujerd, Iran during a period of 10 years (2012-2021). The wind data have been registered by three-hour intervals at the height of 10 m and it has been taken up a study entitled statistical wind data analysis. In this paper, weibull distribution function has been obtained from the wind data. Two important parameters such as waybill's shape factor and scale factor have also been determined by two methods including the maximum likelihood and least square methods. Judgment criterion for Goodness of fit was performed by chi-square test. The wind speed distribution is represented by the typical two-parameter weibull distribution function for all the months except the 9th month of the year (September). Thus, four-parameter weibull distribution function has been developed to analyze the wind speed frequency distribution for September. The diurnal wind speed curves and wind frequency rose have been drawn and analyzed. Also, mean wind speed and density were calculated. The American schedule classification of wind speed was used to determine the wind speed class. It is found that wind speed has the cycle variation. Peak of wind speed occurs 3 times a day with 8-hour intervals. These peaks are around 5, 12 and 21 GMT. Also the prevailing winds in the region are the winds that blow from the southeast to northwest with some deviation around it and the mean wind speed in winters is greater than for other seasons.