The aim of this study is to enhance the fermentation temperature inside the digester by supplying the required thermal energy to be within the desired optimum range (mesophilic range) for biogas production during winter “cold days”. Two 50 L digesters were used in the experiment that was conducted at Solar Energy Laboratory, Department of Agricultural Engineering, Faculty of Agriculture, Ain Shams University, Cairo. One is a treatment digester and the other is a control digester. The treatment digester is thermally enhanced by a parabolic trough collector, while the control digester operated at the ambient temperature. The experiment was conducted through December 2018 and January 2019. The results show that the average temperature in the control digester through the experiment was 21.5°C, while in the treatment digester it was 27.08°C. This means that the parabolic trough collector enhanced the fermentation temperature in the treatment digester by 20.6%. The total biogas yield of the control digester and the treatment digester was 9684.7 mL/kg. T.S. and 24649.69 mL/kg. T.S. respectively. By comparing both productivities, it was found that the productivity of the treatment digester was 2.5 times more than the productivity of the control digester.

The study was conducted on a knapsacksprayer powered by a DC motor through a 12 V lead acid battery charged from a solar panel (photovoltaic) directed to sun rays. The system was installed and tested in the western desert on a small-scale farm at Frafra Oasis (New val-ley). This study aimed to evaluate and develop a knapsack sprayer powered by a solar energy for overcoming operator fatigue and shortage of traditional energy in Egypt’s western desert. The experiments were conducted during the period which starts in August 2019 till Febru-ary 2020. The main parts of the system consist of photovoltaic (PV) or solar cells, charger controller, rechargeable battery, and DC motor speed control with dimmer and pump which was attached with a tank 20 liters capacity for sucking and pressurizing the liquid to the boom of the sprayer through a flexible hose. The main results of experiments were as fol-lows: The time for recharging the battery com-pletely was found 330 minutes (5.5 hours) to charge completely from 10.55 V – 13.85 V, with current intensity 1.67 Ampere. The bat-tery discharge time was varied due to drop the battery voltage from 13.85 – 10.55 Volts. De-pending on the motor speed, which is the time for discharging the battery was found 4 – 9 hours, when motor pulled 0.85 - 1.85 Amps at 2000 - 3400 rpm and this time at deferent speed is enough to spray area 3 - 6.82 fed/day "day work = 6 hours" with application rate 67 - 104.7 l/fed. The number of droplets and the area coverage percentage ranges from 30 – 146.33 drops and 13.96 – 27.97% for one cm2 of simulator targets at a speed ranging from 2000 – 3400 rpm, respectively.

Experiments were performed at a private garden in Al-Qaddbah, Al-Gharbia Governorate, Egypt. The latitude and longitude of the experiment site are 30°56'37''N and 30°47'01'' E, respectively, and the altitude equals 30 m, at the 2019 season, the total landscape area (13.5m x 9m) was divided into 6 treatments each of an area (20.25 m2), three plots were operated using solar system while the other three plots were operated using electric system. The irrigation systems were similar, 4 multi-stream sprayers, (90◦) and the distance between the sprayers was (4.5*4.5 m), different operating times were applied on each plot, under local climatic and working conditions. All the plots were planted with turfgrass (Passpalm10). The obtained results show, at solar energy powered system, uniformity coefficient increased from (65% - 75%) at operating time (10 –30 min), then it decreased during operating time (40 - 60 min), while at electric energy powered system the averages of the uniformity coefficient were (76% - 80%), at operating time (10 –40 min), while at operating time (45 - 60 min) the uniformity coefficient decreased to (75%), due to the silt clogging in the sprayers' filters. The energy saving reached (63%) with solar energy operation rather than electric energy operation in the summer season. The least total cost was (351 L.E/m2/year) at the landscape area (A3 60.75m2), which was irrigated on 3 cycles per day to give the highest uniformity coefficient (75%). When operating the solar batteries at full charge 3 - 4 times for a plot area of (20.25 m2). The hydraulic power obtained was (17.86 –26.74 W), the sprayer radius was (5.3 –5.8 m), at an average pressure of (1.9 -2.5 bar) which gave the best uniformity coefficient. The turf quality index was higher using electric motor rather than solar motor.

The main objective of this investigation was carried out to study the ability of utilizing greenhouse solar dryers for drying of corn in order to obtain the best quality of dried grains for using it as seeds with the least drying time, and comparing with the natural sun drying method. Thus, contributing to increase the productivity. Corn cv. (Giza 168) was used for the experimental work at initial moisture content of 31.73% on dry basis (d.b). Two different drying methods of corn were tested for drying of ear and shelled corn. The two methods were natural sun drying and solar drying using greenhouse type solar dryers at different air velocities (0.5, 1.0 and 1.5 m/s). The experiments were carried out in rice mechanization center at Meet El- Dyba, Kafr El-Sheikh Governorate, Egypt during September 2016.   Experiment included the flowing variables   Two different drying methods (Solar drying method using greenhouse type solar dryer and natural sun drying method). Two different conditions of corn (complete ear-shelled corn). Three different air velocity (0.5, 1.0 and 1.5 m/s). High moisture ear and shelled corn was dried by using solar energy for heating air inside a greenhouse and compared with natural sun drying method. The results of quality tests that included standard germination test, vigor test and tetrazolium test for both drying methods for ear and shelled corn recorded high percentages for all treatments except solar drying of ear corn at air velocities 0.5 and 1.0 m/s. The average air temperature inside the solar dryer at air velocities 0.5 and 1.0 m/s reached to 43.9 and 42.4 ˚C respectively. High temperatures killed the germ of corn so the quality tests were reduced. Germination percentage of natural sun dried ear corn was 97 % and for solar dried samples at air velocities 0.5, 1.0 and 1.5 m/s was 79, 81, and 89%, respectively. The corresponding values for shelled corn were 93, 97 and 98 %.and 95 % for natural sun dried ones. The vigor test of dried ear corn recorded 90 for natural sun drying method and 34, 45, and 66% for solar drying at air velocities of 0.5, 1.0 and 1.5 m/s, respectively. The corresponding values for shelled corn were 86, 96 and 97% respectively, and 82 for natural sun dried samples. The recorded drying times were 26, 24 and 28 hours to reduce the moisture content from an initial level of 31.73 to final level of 14.07% (d.b.) for ear corn and for shelled corn were 20, 16 and 24 hours to reduce the moisture content from an initial level of an initial level of 31.73 to final level of 14.07% (d.b.) for ear corn and for shelled corn were 20, 16 and 24 hours to reduce the moisture content from an initial level of 27.23% to 14.12% compared with 46 and 38 hours for ear and shelled corn dried by natural sun drying method. Hourly costs of ear corn drying were 0.95, 0.88, 1.00 and 1.03 L.E/ kg for solar drying at air velocities 0.5, 1.0 , 1.5m/s and natural sun drying respectively. The corresponding values for shelled corn were 0.74, 0.58, 0.89 and 0.96 L.E/ kg.