Development and evaluation of a dual-purpose machine for chopping and crushing forage crops.

Reducing reliance on fossil fuels with clean and sustainable alternatives is essential for mitigating climate change and global warming-related environmental concerns. Previous researchers have studied the performance of choppers and crushers as separate units powered by diesel or gasoline engines. Nowadays, an increasing interest in producing Eco-friendly machines that stand out for being dual purposes, cost-effectiveness, and with lengths suitable for feeding ruminants are imperative to achieving economic and sustainable goals. Therefore, this study aims to solve these issues and gaps by developing and evaluating a dual-purpose forage machine for chopping and crushing operations to achieve both operations more efficiently and at a lower cost. The developed forage machine's performance was evaluated for chopping operation using maize stalks with four different rotational speeds of 1200, 1400, 1600, and 1800 rpm and four different moisture contents of 22.7, 43.3, 59.8, and 74.6% (w.b.). Also, the crushing operation was evaluated using maize ears with four different crusher speeds of 1200, 1400, 1600, and 1800 rpm and three different sieves with holes' diameters of 6, 8, and 10 mm. The results concluded that the highest efficiencies with values of 94.17 and 92.85% were obtained at 1800 rpm chopper rotational speed and 22.7% moisture content for the chopper and 1200 rpm crusher rotational speed and 10 mm sieve hole diameter for the crusher, respectively. At these proper operational parameters, the machine productivity of 2.44 and 0.31 ton.hr-1, the specific energy requirements of 3.22 and 4.50 kW h.ton-1, and the estimated production costs of 23.56 and 121.24 EGP.ton-1 (1.25 and 6.38 USD.ton-1) were obtained for chopper and crusher, respectively.

Mathematical model for predicting oxygen concentration in tilapia fish farms.

The main aim of this research is to develop a mathematical model to predict the dissolved oxygen in recirculating aquaculture system. The oxygen consumption of the model through the fish respiration and nitrification and the oxygen addition of the model through oxygen generator and water pumping. The effect of different water temperatures (24, 26, 28, 30 and 32 °C) on the dissolved oxygen consumption through fish respiration, biofilter and nitrification and fish growth were studied. An experiment to measure oxygen consumed by fish respiration and biofilteration and fish growth with the growth period and to validate the model results was carried out. The oxygen consumption predicted by the model was in a good agreement with those measured by the system. The oxygen consumption by fish respiration ranged 12.04 to 47.53 g O2 m-3 h-1 experimentally, while it was from 12.01 to 46.06 g O2 m-3 h-1 theoretically. The predicted and measured oxygen consumption through biofilteration values ranged from 0.43 to 21.91 and 0.45 to 23.09 g O2 m-3 h-1, respectively. The individual fish weight from the system ranged from 3.00 to 209.52 g experimentally while it was from 3.00 to 226.25 g theoretically during the whole period.

Production of basil (Ocimum basilicum L.) under different soilless cultures.

The main aim of this paper was to investigate the possibility of growing basil under three soilless systems (aeroponic, hydroponic and peatmoss slab systems). A model was developed to predict the nutrients consumption by basil plants. Shoot and root height, fresh and dry mass of whole plant, nutrients uptake, and oil content were studied during the growth period (after 4 and 7 weeks from transplanting). The results indicated that the shoot lengths of basil plants were 71.67 ± 2.89, 65.67 ± 1.15 and 62.33 ± 2.31 cm at the end of growth period for aeroponic, hydroponic and peatmoss slabs, respectively. The highest value of root height of basil plants was 37.67 ± 6.66 cm for aeroponic system. The dry mass of shoot of basil plants ranged from 28.48 ± 0.91 to 44.77 ± 0.97 and 72.98 ± 0.83 to 117.93 ± 1.40 g plant-1 after 4 and 7 weeks from transplanting, respectively. The highest values of the N, P, K, Ca and Mg uptakes were 753.99 ± 5.65, 224.88 ± 3.05, 449.75 ± 4.59, 529.12 ± 6.63 and 112.44 ± 1.67 mg plant-1 at the end of experimental period, respectively. The basil oil content ranged from 1.129 (1.11%) to 2.520 (1.80%) and 2.664 (1.42%) to 6.318 (1.44%) g plant-1 after 4 and 7 weeks from transplanting, respectively at the same pervious order. The production costs of basil plant were 2.93, 5.27 and 6.24 EGP kg-1 of plant. The model results were in a reasonable agreement with the experimental ones.