فهرست مطالب d. mohammad zamani

Biodiesel 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.

Graphene 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.

The 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.

By 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.

Controlling the humidity and temperature inside the greenhouse is an effective way of plant growth that could be done in different ways. The humidity and temperature of the greenhouse environment could be controlled by the fogging system. A uniform humidity in the greenhouse could be achieved by investigating the effect of various factors on the fluid flow behavior when leaves the spray nozzle. In this study, the effect of three types of BD power fuel injector nozzles (made in Taiwan) in various numbers of 0.03, 0.04, and 0.05 in three pressure levels of 20, 40, and 60 bar on the pattern of fog spray in the environment, spray angle, and spray uniformity was examined. Both methods of experimental and computational fluid dynamics modeling used in this study. For experimental examinations, the greenhouse of Yasuj Airport was used. For evaluation of experimental examinations, a factorial experiment in randomized complete block design with 3 replications was used and to compare the means of treatments Duncan's test was used. To solve the governing equations of flow such as continuity and momentum in the modeling method, FLUENT software is used. The results from experimental study showed that there is a significant association between pressure and nozzle type on the spray angle (P<0.01). The highest fluid spraying was observed in the outlet center of the nozzle, and by moving away from the center of the nozzle the amount of fluid settling was reduced. In this type of sprayer, the best spraying quality was obtained at a pressure of 40 bar. The results from simulation of particle velocity showed that at the pressure of 20 bar, the trend of velocity changes is V-shaped. In the center of the nozzles the velocity of the particles was maximum and then decreased as the particles move towards the sides. Any increments in pressure led to spraying non-uniformity and phenomenon of elongation. However, both simulation and experimental results were matched appropriately.

Despite the dangers of agricultural pesticides for human, animals, and the environment, spraying is the main way to control weeds, pests, and plant diseases. The size of particle and uniformity of toxin distribution during spraying time are two of the most influencing factors in the spraying quality. To achieve this, it is necessary to study the effect of various factors on the behavior and movement pattern of toxin particles from the time of spraying until the moment of settling on the plant. Using experimental method, is the most common method for assessing the quality of spraying. In this research, using ANSYS R17.1 software computational fluid dynamics (CFD) method was used to simulate the fluid behavior as an alternative to the experimental method. Therefore, the effect of three types of Tee Jet nozzles of 0-21, 0-110, and 110-04 with various pressure levels of 2, 3, and 4 bar were evaluated. A factorial experiment with 3 replications in a completely randomized design and Duncan's test were applied to compare the means of treatments. The data from simulation and experimental results demonstrated that the best nozzle in terms of uniform volume distribution of particles was sprayer nozzle 110/03 which has the best spraying uniformity in the three pressure levels studied compared to other nozzles. Comparing the spray angle results revealed that the maximum difference between the experimental method and the simulation was only 8%. Finally, it was concluded that computational fluid dynamics modeling is an appropriate method for predicting the behavior of toxin particles during the spray from the nozzle.

The agricultural sector is in need of a rapid transition from traditional and livelihoods to the stage of advanced production and commercialization, in order to provide food security for the community and to play an effective role in strengthening national independence. Mechanization is an approach that allows the agricultural sector to achieve the stage of commercial production. Without mechanization, there is no clear vision of a dynamic and sustainable agriculture that can rectify the food needs sensibly. The development of mechanization in agricultural societies, especially in the rural areas, has been accompanied by problems that the identification of the factors affecting it can help plan to eliminate them. Therefore, in the present study, the effect of the fragmentation of land on the development of agricultural mechanization in the rural districts has been investigated. The research type is applied and descriptive-analytic, survey method has been used and information has been collected through a questionnaire from 420 users in Jiroft city. The data were analyzed using a hierarchical analytical process technique using Expert Choice11 software. The research findings show that the family-social factor in the city of Jiroft was the main deterrent to the lack of development of mechanization and the cultural-communication, educational-technical, lawful-legal, and economic-financial factors were placed in the next priorities. It is proposed to implement the development of mechanization, the modernization of modern technology, education and promotion, building trust, credit and financial facilities for the modernization of agricultural implements.