The influence of greenhouse evaporative cooling systems (based on misting, and fan pads cooling systems) on the microclimatic conditions of greenhouse cucumber was studied and investigated in two fiberglass greenhouses combined with roof shading black net screen situated on the roof of the Agricultural Engineering Department, University of Mansoura. Measurements were executed during several days (122 days) in the hot summer of 2009; (G1) with a mist system operating 15 sec every 15 min., (G2) with a pad-fan system. In order to compare between the cooling systems, air temperatures and relative humidity inside and outside the greenhouses were measured and recorded. Experimental data revealed that the pad-fan cooling system was able to keep the air temperature within the greenhouse at rather low levels. The internal air temperature stayed 8.0°C below outside, even during hot afternoons (Tao > 35°C). Whereas, the evaporative cooling using mist system kept the greenhouse air temperature above the set point temperature by an average of 4.9°C. Therefore, the internal air temperature stayed 4.2°C below outside. Due to the short length of the greenhouse (8 m), small temperature gradients (2.9°C) were observed from wet pads to extracting fan. The cooling system using fan-pad system inside the greenhouse (G2) was on the average more efficient than the misting system inside the greenhouse (G1) by 22.5% due to the cooling operation period for the greenhouse (2) was longer than that for the greenhouse (1), accordingly, the water temperature of cooling system (2) was lower than that in misting system (G1). The total fresh yield of cucumber crop per square meter for greenhouse (G1) and greenhouse (G2) was 3.805 and 5.491 kg/m 2 , respectively. Therefore, the greenhouse (G2) produced 1.686 kg /m 2 (44.31%) more than the greenhouse (G1).

No abstract

The aim of this study was to evaluate the feasibility of composting fallen leaves and cattle dung and the effect of turning frequency on final compost quality. A bioreactor vessel was designed, manufactured, and situated on the roof of the Agricultural Engineering Department, Faculty of Agriculture, Mansoura University for rapid composting of admixture leaves and cattle dung from November 2008 until June 2010. This bioreactor vessel is conical in shape (right frustum of cone) and made of double layer of stainless steel sheet 1 mm thick with a net volume of 0.1094 m 3 . A series of experiments were executed to investigate some engineering factors affecting performance of composting process such as; size of fallen leaves and stirring or turning frequency. Laboratory tests were also carried out to assess and evaluate some physical and chemical properties of raw composting materials, fresh compost, and final compost after curing process. Two different particle sizes of fallen leaves (shredded leaves of 2.0-5.5 mm and complete leaves) and one aeration rate (0.007 m 3 /min) were functioned. Two different levels of manual stirring (without and with stirring once every six days) were used. The obtained results revealed that, to maximize the microbial activity and speed up the composting process of admixture materials, they would be aerated by a rate of 0.007 m 3 /min, stirred once every six days, and shredded fallen leaves to a smaller particles size. The obtained results also showed that, the final compost contented Nitrogen (N), Phosphorus (P), and potassium (K) of 3.181%, 0.318%, and 3.790%, respectively. They also revealed that, there were no weed seeds found in all treatment samples of fresh and final composts. Rising up the temperature of admixture materials and persisting from the first day until the end of fifth day during the thermophilic phase caused in destructed of pathogens and other organisms.

No abstract

The experimental work was carried out in the wastes treatment laboratory of the Agricultural Engineering Department, Mansoura University to assess the optimal aeration rate and mechanical stirring to produce compost. C/N ratio of the examined raw materials was calculated to find out the mixing ratios of the correct ingredients. The composting of digested buffalo dung and maize stover has been investigated in a forced-aeration composting system at three different aeration rates (0.0003, 0.0005 and 0.0007 m 3 /s) and two different levels of mechanical stirring (Once and twice a week) to specify the optimal aeration rate and mechanical stirring system and used them with fresh buffalo dung and maize stover at moisture content of 65% w.b. Two control (traditional system) experiments were performed, the first (control1) was digested buffalo dung and the second (control2) was fresh buffalo dung. Temperatures of ambient air, bioreactor vessel, control1 and control2 were measured and recorded. Chemical analysis for the raw materials and the final compost was also carried out. The obtained results indicated that, the buffalo dung (digested or fresh) can be mixed with shredded maize stover together at a ratio of 2 part of buffalo dung to 1 part of maize stover (by weight) to produce compost. It is recommended to use aeration rate of 0.0005 m 3 /s at once a week mechanical stirring to produce compost with good properties inside the bio-reactor. According to the biological analysis, the produced compost from the digested buffalo dung is better than that from the fresh buffalo dung.