The experiments of this study were carried out to optimize some pelletization parameters and thei... more The experiments of this study were carried out to optimize some pelletization parameters and their effects on the quality of feed processing. The pelletizer was evaluated under different parameters including feeding rate and feed pellets. Pelletization process was evaluated by studying the specific energy consumption and quality of feed pellets at different operation conditions. The pelletization energy consumption ranged from 179.14-204.60 kJ/kg for rabbits, 163.60-184.87 kJ/kg for poultry and 41.06-59.67 kJ/kg for large animal feed pellets. The compression and shear forces of pellets ranged from 277. 16-309.11 and 30.12-38.02 N, respectively for rabbits feed pellet, 99.22-106.08 and 25.60-29.60 N, respectively for poultry feed pellets and 135.63-242.08 and 59.92-104.66 N, respectively for large animals feed pellets.
This work presents a useful information about different fish feed pellets, which will be database... more This work presents a useful information about different fish feed pellets, which will be database for the people work in the intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface area of pellets fish feed value ranged from 10.57 to 71.13 mm 2 . The volume of pellets fish feed 4.04 to 79.09 mm 3 . The weight of 100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m -3 . The durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51 to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing load of pellets fish feed value ranged from 6.13 to 33.28 N.
The objective of this work was to investigate the efficiency of both double drain and screen filt... more The objective of this work was to investigate the efficiency of both double drain and screen filter on solids removal in recirculating aquaculture system to improve the water quality and increase the fish growth rate. A model was developed to determine the solids removal in recirculating aquaculture system. By fitting the predictions of the model to measured settleable and suspended solids, settleabe solids removal was determined that about 0.0304 to 0.0556 kg m-3 (30.40 to 55.60 mg l-1) while it was 0.039 kg m-3 (39 mg l-1) for the theoretical approach and suspended solids removal was determined that about 0.0123 to 0.0806 kg m-3 (12.30 to 80.60 mg l-1) while it was from 0.0124 to 0.1425 kg m-3 for the theoretical approach. It was calculated that the hydrocyclone and drum filter efficiency to remove the solids from the system ranged from 27.4 to 57.79 % and15.46 to 57.71 % respectively. It was calculated that the hydrocyclone and drum filter efficiency to remove the solids from the system ranged from 27.4 to 57.79 % and15.46 to 57.71 % respectively. The daily average of settleable and suspended solids removed by hydrocyclone and drum filter ranged from 0.33 to 6.26 kg/day and 0.11 to 11.43 kg/day, respectively. The model results were in a reasonable agreement with the experimental ones.
This work presents a useful information about different fish feed pellets, which will be database... more This work presents a useful information about different fish feed pellets, which will be database for the people work in the intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface area of pellets fish feed value ranged from 10.57 to 71.13 mm2. The volume of pellets fish feed 4.04 to 79.09 mm3. The weight of 100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m-3. The durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51 to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing load of pellets fish feed value ranged from 6.13 to 33.28 N.
A mathematical model of heat balance was developed to predict the compost temperature during the ... more A mathematical model of heat balance was developed to predict the compost temperature during the maturation stage. The components of the energy balance of the compost pile which include: heat gained (heat generation and solar radiation) and heat lost (radiation, evaporation, convection, and conduction) at different ambient temperatures. The model was able to predict the pile temperature at different ambient temperatures (15, 20, 25, 30 and 35°C) and different airflow rates (0.7, 1.1 and 1.5 mg air s-1 kg-1 dry matter). The results showed that the pile temperature increases with increasing ambient temperature and it decreases with increasing airflow rates, where, as the ambient temperature increased from 15 to 35°C, the pile temperature increased from 33.40 to 37.41°C, and when the airflow rates increased from 0.7 to 1.5 mg air s-1 kg-1 dry matter, the pile temperature decreased from 34.40 to 32.39°C. The pile temperature increased slightly and reached a maximum value at day 14. It indicates that the net energy gained to the pile increases with increasing ambient temperature, meanwhile, the heat lost decreases with increasing ambient temperature. The model results indicated that the predicted daily temperature was in a reasonable agreement with those measured ones and other data in literature (Barrena et al. and Ahn et al.) at different ambient temperatures and airflow rates, where, it ranged from 30.30 to 73.40°C, while it was from 18.0 to 71.0°C experimentally during the whole period of compost maturation.
Linear programming is used to select systems based on minimization of total annual cost using aer... more Linear programming is used to select systems based on minimization of total annual cost using aeration devices for pond to give optimum oxygen. By linear programming model results, one aerator of the type air-injector (0.75 kW) was found suitable for a pond of sizes 0.1, 0.2, and 0.4 ha by least-cost. Splash aerator (0.75 kW) was found suitable for single use for pond of sizes 0.8 ha by least-cost, and suitable in addition to diesel paddlewheel (9 kW) for large pond size (3.2 ha). Diesel paddlewheel aerators (6 kW and 9 kW) were found suitable for large pond sizes (1.6, 3.2, 4.0, and 4.8 ha). Diesel paddlewheel aerators are suitable for large ponds under Egyptian conditions.
The influence of environmental parameters on growth rate, fresh yield, and irrigation performance... more The influence of environmental parameters on growth rate, fresh yield, and irrigation performance of color sweet pepper (Capsicum annuum var annuum cv.) were studied in three different types of greenhouse forms. The three different systems are; gable-even-span form, flat roof net-house, and modified Quonset greenhouse during 2002/2003 seasons. Diurnal external and internal, air temperature, air relative humidity, vapour pressure deficit (VPD), and light intensity were measured to analysis their correlation with sweet pepper crop yield response. The plants were periodically collected throughout their growth cycles to measure vegetative, flowering and yields. For irrigation performance test three indicators were determined; annual relative irrigation supply (ARIS), irrigation water use efficiency (IWUE), and annual water productivity (AWP). The obtained results showed that, the gable-even-span greenhouse (fully controlled) gave the best growth rate between vegetative and generative parts of the plant as compared with other systems. The greatest plant height (7.7 cm/week) achieved during autumn season for the three different greenhouse forms. While, the plant height rates during winter season for the three different greenhouse forms, respectively, were 5.8, 1.8 and 4.0 cm/week. The obtained data also revealed that the leaf area index (LAI) for the three different forms was 6.16, 2.23, and 2.44, respectively. Therefore, the greatest fresh yield and quality of sweet pepper were achieved by gable-even-span form (fully controlled greenhouse) as compared with other forms of greenhouse. Mean annual irrigation supply (ARIS) values were slightly up to 1 for the three different forms. Mean irrigation water use efficiency (IWUE) values for the three different forms ranged from 3.98 to 9.75 kg/m3, while (AWP) in the fully controlled greenhouse was higher than 3.18 and 4.08 times from flat roof net-house and modified Quonset, respectively due to increase the irrigation water use efficiency (IWUE) and high value of yield grown off-season.
n onion peeling machine was designed, manufactured, developed and evaluated to suit the small and... more n onion peeling machine was designed, manufactured, developed and evaluated to suit the small and medium processing units. The onion peeling machine consists of seven parts, main frame, peeling drum, inlet and outlet openings, collection basin, water and air supplying systems, and power transmission. The machine was evaluated using different onion bulb sizes (small, medium & large). A mixed sample of different sizes was also tested. The evaluation process was conducted under three different drum rotational speeds (30, 40 and 50 rpm), three different peeling residence times (1, 2 and 3mins) and three different batch loads (18, 24 and 30kg). The optimum peeling efficiency of 74.9, 65.24, 80.08 and 85.45% were obtained at 24kg batch load (0.36 ton/h.), 2min peeling residence time and 40 rpm for small, medium, mixed and large sizes respectively. Water pump and air compressor were added to the peeler to improve the peeling efficiency, and it was tested under the previous conditions. The corresponding values of peeling efficiency for the machine with pump water at water pressure of 400kPa were 76.73, 83.06, 99.20 and 87.49 %, respectively. While they were 76.33, 72.87, 87.530 and 88.37%, respectively for air pumping at pressure of 500kPa. The estimated costs of onions peeling machine were 28.47, 29.56 and33.75 L.E/ton for the machine only, machine with water pump and machine with air compressor respectively. These values of estimated costs using the developed machine are very competitive with the cost of manual peeling process which approached about 75 L.E/ton.
The experiments of this study were carried out to optimize some pelletization parameters and thei... more The experiments of this study were carried out to optimize some pelletization parameters and their effects on the quality of feed processing. The pelletizer was evaluated under different parameters including feeding rate and feed pellets. Pelletization process was evaluated by studying the specific energy consumption and quality of feed pellets at different operation conditions. The pelletization energy consumption ranged from 179.14- 204.60 kJ/kg for rabbits, 163.60- 184.87 kJ/kg for poultry and 41.06- 59.67 kJ/kg for large animal feed pellets. The compression and shear forces of pellets ranged from 277.16- 309.11 and 30.12- 38.02 N, respectively for rabbits feed pellet, 99.22- 106.08 and 25.60- 29.60 N, respectively for poultry feed pellets and 135.63- 242.08 and 59.92- 104.66 N, respectively for large animals feed pellets.
The experiments of this study were carried out to optimize some grinding parameters and their eff... more The experiments of this study were carried out to optimize some grinding parameters and their effects on the quality of corn for feed processing. The hammer mill was evaluated under different parameters including grain moisture content and sieve hole diameter. Grinding process was evaluated by studying the performance, energy consumption, grinding index, grinding ability index, ground quality at different operation conditions. The results revealed that the mill performance, specific energy, energy density, grinding index and grinding ability index ranged from 0.70- 6.83 Mg/h, 3.38- 32.72 kJ/kg, 1.99- 18.82 MJ/m3, 12.35- 91.28 kJ.mm0.5/kg and 0.81- 6.00 kJ/m2, respectively. Mean weight diameter, size reduction, bulk density and grinding effectiveness ranged from 1.47- 2.89 mm, 2.60- 5.10 times, 524.58- 621.34 kg/m3 and 8.88- 14.40, respectively at different sieve hole diameter and grain moisture content.
The main objective of this research is to study the effect of source of nutrients, water flow rat... more The main objective of this research is to study the effect of source of nutrients, water flow rate and length of gully to know the possibility of producing lettuce plants depending on the nutrients existing in effluent fish farm as compared with the lettuce production using standard nutrient solutions. To achieve that was studied the effect of source of nutrients (effluent fish water and nutrient solution), flow rate (1.0, 1.5 and 2.0 L min-1) and length of gully (2, 3 and 4 m) on the following parameters: nutrient uptake, dry weight and NO3-N content in plant. The obtained results indicated that the fresh and dry weight of shoots increased in nutrient solution over those of effluent fish farm. The fresh and dry weight of shoots decreased with increasing the flow rate and the length of gully. The dry weight of roots increased in nutrient solution over those of effluent fish farm. The dry weight of roots decreased with increasing the flow rate and the length of gully. The NO3-N content significantly increased in nutrient solution over those of effluent fish farm. The NO3-N content decreased with increasing the flow rate and length of gully. The NO3/protein ratio increased in nutrient solution over those of effluent fish farm.
The prediction of dissolved oxygen in aquaculture ponds throughout the year is essential to the d... more The prediction of dissolved oxygen in aquaculture ponds throughout the year is essential to the design and evaluates the potential aquaculture sites. A computer model has been developed to simulate dissolved oxygen in a fish pond. A short-term Dissolved Oxygen (DO) fluctuation of a fishpond was developed by using various simple equations and continuous measurement of DO, temperature and solar intensity. Numerical computation has been performed for a typical winter (17th of January) and summer (17th of July) days. Results from model verification runs showed that the model performance was satisfactory with respect to aquaculture pond dissolved oxygen. The relative percentage of error (RPE) for the 24 hours of simulation was 0.2818% and the correlation coefficient between predicted and measured dissolved oxygen was 0.97. The predicted dissolved oxygen was fluctuated between -0.101 to 0.113gO2m-3lower and higher than the measured dissolved oxygen for most of the 24 hour simulation. The predicted results indicate that DO is affected by weather variables, especially solar radiation. The dissolved oxygen (DO) values ranged from 4.4 to 8.7 g m-3, where it reached the highest value (8.7) at 17:00 h, while it reached the lowest value (4.4) at 6:00 h. The fish growth model results indicated that the total cycle time between the stocking and the harvesting is about 180-190 days during the summer months; compared with the total cycle time in natural setting is about 210-240 days
This study presents a model development to determine the optimum orientation of a greenhouse for ... more This study presents a model development to determine the optimum orientation of a greenhouse for year round applications under different climatic conditions. The most commonly structural form used in the study is gable-even-span single type greenhouse with different orientations. Total solar radiation flux incident on each wall, included vertical surfaces and inclined roofs, was computed for solar greenhouse orientations and compared for January and July months of the year at the northern hemisphere. Model validation was executed for the measured global solar radiation data on a horizontal surface at the Faculty of Agriculture, Toukh, Qalubia, Egypt (30.36°N, 31.22°E and altitude 15m,. The obtained results showed that, the predicted and measured values are in close agreement. Results also revealed that, the orientation of east-west (E) and south-north (S) of gable even-span solar greenhouse, respectively, was the best suited during January and July months
Micro-screen rotating drum filters are an alternative to sand filtration especially when excessiv... more Micro-screen rotating drum filters are an alternative to sand filtration especially when excessive waste water is a concern. The filtering process of drum screen filters is very simple, yet very efficient and reliable due to their overall design and operation. Drum filters are designed with few moving parts to ensure a long life with low operating/ maintenance costs. Micro-screening essentially captures particles on a screen fabric while letting the water pass. This paper describes a design of two an industrial-scale drum screen filters driven by undershot wheel and its performance installed in recirculating aquaculture system culturing tilapia at El-Nenaeia fish farm. These filters are consisted of a woven metal mesh of 100 µm. The design criteria for solids loading rate in the influent water is 10 kg m-2min-1. The results indicate that the design parameters of the filter such as surface are and rotation speed were affected by the water flow rate, where the surface area and drum speed ranged from 1.58-27.87 m2, and 1.05-8.40, respectively. The results also indicated that the efficiency of filter decreased during the first two months compared to the last two months of fish growth period, with an average 34.22 ±8.85% during the first 60 days and an average 52.41 ±16.77 % during the last period. Using water wheels for driving the screen filter is very important in saving energy, where the filter with such dimensions needs 1.0 hp for driving it, which represents 18.0 kW daily
The prediction of aquaculture pond temperatures throughout the year is essential to the design an... more The prediction of aquaculture pond temperatures throughout the year is essential to the design and evaluation of potential aquaculture sites. An energy balance was developed for earthen aquaculture ponds to 1) determine the relative importance of energy transfer mechanisms affecting pond temperature; 2) predict pond temperatures, and 3) estimate the energy required to control pond temperatures. A computer program was developed to solve the energy balance using weather and pond temperature data. Initial simulations for aquaculture pond validated the model’s ability to predict pond temperature changes. The dominant energy transfer mechanisms for ponds were solar radiation, pond radiation and longwave sky radiation. Finally, management and design questions about the warm water aquaculture ponds, such as the pond temperature throughout an average weather year, the amount of energy needed to maintain the pond temperature constant and the amount of energy required to warm a pond from 10 to 28°C, were answered by additional simulations.
The performance of a model developed by Ali (2006) to simulate aquaculture pond temperature was e... more The performance of a model developed by Ali (2006) to simulate aquaculture pond temperature was evaluated using sensitivity analysis and the model verified with data from aquaculture pond. The sensitivity analysis showed that output varied linearly with changes in average air temperature and solar radiation. Results from model verification runs showed that the model performance was satisfactory with respect to aquaculture pond temperature. In the future, the model will be used to investigate the effects of aquaculture pond temperature on daily growth rate to obtain the weight of individual fish throughout the year
This paper aims to study the performance of using the airlift pump as a pumping and aeration syst... more This paper aims to study the performance of using the airlift pump as a pumping and aeration system in the aquacultural systems. Water flow rates, dissolved oxygen and temperature were measured, and standard aeration efficiencies (SAE) were determined in airlift pumps 5.0, 7.5 and 10.0cm in diameter, 0.5, 1.0 and 1.5m in length and submergence of airlifts were 70, 80 and 90% from pipe length to develop performance data that might be useful to aquaculturists. Air was injected through leaky pipes ( 13mm). The results indicated that, the water flow rate and standard aeration efficiency (SAE) increased with increasing of both length and diameter of airlift pumps and submergence ratio. The water flow rate increased with air injection until it reaches to the peak then it decreased. The standard aeration efficiency (SAE) increased in narrow range with increasing the air flow rate, after this range it decreased with increasing the air flow rate.
This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in t... more This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in the aquacultural systems. Air pressure in the pipe, standard oxygen transfer rate (SOTR), and standard aeration efficiency (SAE) were determined to evaluate the performance of these pipes under different air flow rates (14.1-106.0 m3/h) and water hydrostatic pressures (0.5-2.0 m H2O) for five and ten pipes on the line. The results indicated that the air pressure increased with increasing of both hydrostatic pressure and airflow rate. The effect of the hydrostatic pressure on the air pressure was higher than that of the air flow rate. The standard oxygen transfer rate (SOTR) increased with increasing the hydrostatic pressure in the aeration tank. Using ten leaky pipes on the air pipe caused an increase in the standard oxygen transfer rate (SOTR) compared to the use of five pipes treatment. The standard aeration efficiency (SAE) decreased with increasing the air flow rate. It could be concluded also that, the effect of air flow rate on the SAE is greater than that of the hydrostatic pressure. The results revealed also that the SAE increased with increasing the number of leaky pipes.
This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in t... more This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in the aquacultural systems. Air pressure in the pipe, standard oxygen transfer rate (SOTR), and standard aeration efficiency (SAE) were determined to evaluate the performance of these pipes under different air flow rates (14.1-106.0 m3/h) and water hydrostatic pressures (0.5-2.0 m H2O) for five and ten pipes on the line. The results indicated that the air pressure increased with increasing of both hydrostatic pressure and airflow rate. The effect of the hydrostatic pressure on the air pressure was higher than that of the air flow rate. The standard oxygen transfer rate (SOTR) increased with increasing the hydrostatic pressure in the aeration tank. Using ten leaky pipes on the air pipe caused an increase in the standard oxygen transfer rate (SOTR) compared to the use of five pipes treatment. The standard aeration efficiency (SAE) decreased with increasing the air flow rate. It could be concluded also that, the effect of air flow rate on the SAE is greater than that of the hydrostatic pressure. The results revealed also that the SAE increased with increasing the number of leaky pipes.
El-Nenaeia Company has developed a commercial fish production demonstration utilizing water recyc... more El-Nenaeia Company has developed a commercial fish production demonstration utilizing water recycle technology developed at Banha University, Faculty of Agriculture, Agricultural Engineering Department. The fish production system is designed in a 32.0 m long by 12.0 m wide. Fish production activities began in the spring of 1998. The facility is designed to produce 30 tons of fish annually, with the first crop being tilapia. The project is being operated as a public demonstration of this technology, with biological, engineering and economic data being collected by research personnel at El-Nenaeia Company. This paper outlines the design of the recirculating system technology used to recycle water through the main fish production tanks.
The experiments of this study were carried out to optimize some pelletization parameters and thei... more The experiments of this study were carried out to optimize some pelletization parameters and their effects on the quality of feed processing. The pelletizer was evaluated under different parameters including feeding rate and feed pellets. Pelletization process was evaluated by studying the specific energy consumption and quality of feed pellets at different operation conditions. The pelletization energy consumption ranged from 179.14-204.60 kJ/kg for rabbits, 163.60-184.87 kJ/kg for poultry and 41.06-59.67 kJ/kg for large animal feed pellets. The compression and shear forces of pellets ranged from 277. 16-309.11 and 30.12-38.02 N, respectively for rabbits feed pellet, 99.22-106.08 and 25.60-29.60 N, respectively for poultry feed pellets and 135.63-242.08 and 59.92-104.66 N, respectively for large animals feed pellets.
This work presents a useful information about different fish feed pellets, which will be database... more This work presents a useful information about different fish feed pellets, which will be database for the people work in the intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface area of pellets fish feed value ranged from 10.57 to 71.13 mm 2 . The volume of pellets fish feed 4.04 to 79.09 mm 3 . The weight of 100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m -3 . The durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51 to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing load of pellets fish feed value ranged from 6.13 to 33.28 N.
The objective of this work was to investigate the efficiency of both double drain and screen filt... more The objective of this work was to investigate the efficiency of both double drain and screen filter on solids removal in recirculating aquaculture system to improve the water quality and increase the fish growth rate. A model was developed to determine the solids removal in recirculating aquaculture system. By fitting the predictions of the model to measured settleable and suspended solids, settleabe solids removal was determined that about 0.0304 to 0.0556 kg m-3 (30.40 to 55.60 mg l-1) while it was 0.039 kg m-3 (39 mg l-1) for the theoretical approach and suspended solids removal was determined that about 0.0123 to 0.0806 kg m-3 (12.30 to 80.60 mg l-1) while it was from 0.0124 to 0.1425 kg m-3 for the theoretical approach. It was calculated that the hydrocyclone and drum filter efficiency to remove the solids from the system ranged from 27.4 to 57.79 % and15.46 to 57.71 % respectively. It was calculated that the hydrocyclone and drum filter efficiency to remove the solids from the system ranged from 27.4 to 57.79 % and15.46 to 57.71 % respectively. The daily average of settleable and suspended solids removed by hydrocyclone and drum filter ranged from 0.33 to 6.26 kg/day and 0.11 to 11.43 kg/day, respectively. The model results were in a reasonable agreement with the experimental ones.
This work presents a useful information about different fish feed pellets, which will be database... more This work presents a useful information about different fish feed pellets, which will be database for the people work in the intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface area of pellets fish feed value ranged from 10.57 to 71.13 mm2. The volume of pellets fish feed 4.04 to 79.09 mm3. The weight of 100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m-3. The durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51 to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing load of pellets fish feed value ranged from 6.13 to 33.28 N.
A mathematical model of heat balance was developed to predict the compost temperature during the ... more A mathematical model of heat balance was developed to predict the compost temperature during the maturation stage. The components of the energy balance of the compost pile which include: heat gained (heat generation and solar radiation) and heat lost (radiation, evaporation, convection, and conduction) at different ambient temperatures. The model was able to predict the pile temperature at different ambient temperatures (15, 20, 25, 30 and 35°C) and different airflow rates (0.7, 1.1 and 1.5 mg air s-1 kg-1 dry matter). The results showed that the pile temperature increases with increasing ambient temperature and it decreases with increasing airflow rates, where, as the ambient temperature increased from 15 to 35°C, the pile temperature increased from 33.40 to 37.41°C, and when the airflow rates increased from 0.7 to 1.5 mg air s-1 kg-1 dry matter, the pile temperature decreased from 34.40 to 32.39°C. The pile temperature increased slightly and reached a maximum value at day 14. It indicates that the net energy gained to the pile increases with increasing ambient temperature, meanwhile, the heat lost decreases with increasing ambient temperature. The model results indicated that the predicted daily temperature was in a reasonable agreement with those measured ones and other data in literature (Barrena et al. and Ahn et al.) at different ambient temperatures and airflow rates, where, it ranged from 30.30 to 73.40°C, while it was from 18.0 to 71.0°C experimentally during the whole period of compost maturation.
Linear programming is used to select systems based on minimization of total annual cost using aer... more Linear programming is used to select systems based on minimization of total annual cost using aeration devices for pond to give optimum oxygen. By linear programming model results, one aerator of the type air-injector (0.75 kW) was found suitable for a pond of sizes 0.1, 0.2, and 0.4 ha by least-cost. Splash aerator (0.75 kW) was found suitable for single use for pond of sizes 0.8 ha by least-cost, and suitable in addition to diesel paddlewheel (9 kW) for large pond size (3.2 ha). Diesel paddlewheel aerators (6 kW and 9 kW) were found suitable for large pond sizes (1.6, 3.2, 4.0, and 4.8 ha). Diesel paddlewheel aerators are suitable for large ponds under Egyptian conditions.
The influence of environmental parameters on growth rate, fresh yield, and irrigation performance... more The influence of environmental parameters on growth rate, fresh yield, and irrigation performance of color sweet pepper (Capsicum annuum var annuum cv.) were studied in three different types of greenhouse forms. The three different systems are; gable-even-span form, flat roof net-house, and modified Quonset greenhouse during 2002/2003 seasons. Diurnal external and internal, air temperature, air relative humidity, vapour pressure deficit (VPD), and light intensity were measured to analysis their correlation with sweet pepper crop yield response. The plants were periodically collected throughout their growth cycles to measure vegetative, flowering and yields. For irrigation performance test three indicators were determined; annual relative irrigation supply (ARIS), irrigation water use efficiency (IWUE), and annual water productivity (AWP). The obtained results showed that, the gable-even-span greenhouse (fully controlled) gave the best growth rate between vegetative and generative parts of the plant as compared with other systems. The greatest plant height (7.7 cm/week) achieved during autumn season for the three different greenhouse forms. While, the plant height rates during winter season for the three different greenhouse forms, respectively, were 5.8, 1.8 and 4.0 cm/week. The obtained data also revealed that the leaf area index (LAI) for the three different forms was 6.16, 2.23, and 2.44, respectively. Therefore, the greatest fresh yield and quality of sweet pepper were achieved by gable-even-span form (fully controlled greenhouse) as compared with other forms of greenhouse. Mean annual irrigation supply (ARIS) values were slightly up to 1 for the three different forms. Mean irrigation water use efficiency (IWUE) values for the three different forms ranged from 3.98 to 9.75 kg/m3, while (AWP) in the fully controlled greenhouse was higher than 3.18 and 4.08 times from flat roof net-house and modified Quonset, respectively due to increase the irrigation water use efficiency (IWUE) and high value of yield grown off-season.
n onion peeling machine was designed, manufactured, developed and evaluated to suit the small and... more n onion peeling machine was designed, manufactured, developed and evaluated to suit the small and medium processing units. The onion peeling machine consists of seven parts, main frame, peeling drum, inlet and outlet openings, collection basin, water and air supplying systems, and power transmission. The machine was evaluated using different onion bulb sizes (small, medium & large). A mixed sample of different sizes was also tested. The evaluation process was conducted under three different drum rotational speeds (30, 40 and 50 rpm), three different peeling residence times (1, 2 and 3mins) and three different batch loads (18, 24 and 30kg). The optimum peeling efficiency of 74.9, 65.24, 80.08 and 85.45% were obtained at 24kg batch load (0.36 ton/h.), 2min peeling residence time and 40 rpm for small, medium, mixed and large sizes respectively. Water pump and air compressor were added to the peeler to improve the peeling efficiency, and it was tested under the previous conditions. The corresponding values of peeling efficiency for the machine with pump water at water pressure of 400kPa were 76.73, 83.06, 99.20 and 87.49 %, respectively. While they were 76.33, 72.87, 87.530 and 88.37%, respectively for air pumping at pressure of 500kPa. The estimated costs of onions peeling machine were 28.47, 29.56 and33.75 L.E/ton for the machine only, machine with water pump and machine with air compressor respectively. These values of estimated costs using the developed machine are very competitive with the cost of manual peeling process which approached about 75 L.E/ton.
The experiments of this study were carried out to optimize some pelletization parameters and thei... more The experiments of this study were carried out to optimize some pelletization parameters and their effects on the quality of feed processing. The pelletizer was evaluated under different parameters including feeding rate and feed pellets. Pelletization process was evaluated by studying the specific energy consumption and quality of feed pellets at different operation conditions. The pelletization energy consumption ranged from 179.14- 204.60 kJ/kg for rabbits, 163.60- 184.87 kJ/kg for poultry and 41.06- 59.67 kJ/kg for large animal feed pellets. The compression and shear forces of pellets ranged from 277.16- 309.11 and 30.12- 38.02 N, respectively for rabbits feed pellet, 99.22- 106.08 and 25.60- 29.60 N, respectively for poultry feed pellets and 135.63- 242.08 and 59.92- 104.66 N, respectively for large animals feed pellets.
The experiments of this study were carried out to optimize some grinding parameters and their eff... more The experiments of this study were carried out to optimize some grinding parameters and their effects on the quality of corn for feed processing. The hammer mill was evaluated under different parameters including grain moisture content and sieve hole diameter. Grinding process was evaluated by studying the performance, energy consumption, grinding index, grinding ability index, ground quality at different operation conditions. The results revealed that the mill performance, specific energy, energy density, grinding index and grinding ability index ranged from 0.70- 6.83 Mg/h, 3.38- 32.72 kJ/kg, 1.99- 18.82 MJ/m3, 12.35- 91.28 kJ.mm0.5/kg and 0.81- 6.00 kJ/m2, respectively. Mean weight diameter, size reduction, bulk density and grinding effectiveness ranged from 1.47- 2.89 mm, 2.60- 5.10 times, 524.58- 621.34 kg/m3 and 8.88- 14.40, respectively at different sieve hole diameter and grain moisture content.
The main objective of this research is to study the effect of source of nutrients, water flow rat... more The main objective of this research is to study the effect of source of nutrients, water flow rate and length of gully to know the possibility of producing lettuce plants depending on the nutrients existing in effluent fish farm as compared with the lettuce production using standard nutrient solutions. To achieve that was studied the effect of source of nutrients (effluent fish water and nutrient solution), flow rate (1.0, 1.5 and 2.0 L min-1) and length of gully (2, 3 and 4 m) on the following parameters: nutrient uptake, dry weight and NO3-N content in plant. The obtained results indicated that the fresh and dry weight of shoots increased in nutrient solution over those of effluent fish farm. The fresh and dry weight of shoots decreased with increasing the flow rate and the length of gully. The dry weight of roots increased in nutrient solution over those of effluent fish farm. The dry weight of roots decreased with increasing the flow rate and the length of gully. The NO3-N content significantly increased in nutrient solution over those of effluent fish farm. The NO3-N content decreased with increasing the flow rate and length of gully. The NO3/protein ratio increased in nutrient solution over those of effluent fish farm.
The prediction of dissolved oxygen in aquaculture ponds throughout the year is essential to the d... more The prediction of dissolved oxygen in aquaculture ponds throughout the year is essential to the design and evaluates the potential aquaculture sites. A computer model has been developed to simulate dissolved oxygen in a fish pond. A short-term Dissolved Oxygen (DO) fluctuation of a fishpond was developed by using various simple equations and continuous measurement of DO, temperature and solar intensity. Numerical computation has been performed for a typical winter (17th of January) and summer (17th of July) days. Results from model verification runs showed that the model performance was satisfactory with respect to aquaculture pond dissolved oxygen. The relative percentage of error (RPE) for the 24 hours of simulation was 0.2818% and the correlation coefficient between predicted and measured dissolved oxygen was 0.97. The predicted dissolved oxygen was fluctuated between -0.101 to 0.113gO2m-3lower and higher than the measured dissolved oxygen for most of the 24 hour simulation. The predicted results indicate that DO is affected by weather variables, especially solar radiation. The dissolved oxygen (DO) values ranged from 4.4 to 8.7 g m-3, where it reached the highest value (8.7) at 17:00 h, while it reached the lowest value (4.4) at 6:00 h. The fish growth model results indicated that the total cycle time between the stocking and the harvesting is about 180-190 days during the summer months; compared with the total cycle time in natural setting is about 210-240 days
This study presents a model development to determine the optimum orientation of a greenhouse for ... more This study presents a model development to determine the optimum orientation of a greenhouse for year round applications under different climatic conditions. The most commonly structural form used in the study is gable-even-span single type greenhouse with different orientations. Total solar radiation flux incident on each wall, included vertical surfaces and inclined roofs, was computed for solar greenhouse orientations and compared for January and July months of the year at the northern hemisphere. Model validation was executed for the measured global solar radiation data on a horizontal surface at the Faculty of Agriculture, Toukh, Qalubia, Egypt (30.36°N, 31.22°E and altitude 15m,. The obtained results showed that, the predicted and measured values are in close agreement. Results also revealed that, the orientation of east-west (E) and south-north (S) of gable even-span solar greenhouse, respectively, was the best suited during January and July months
Micro-screen rotating drum filters are an alternative to sand filtration especially when excessiv... more Micro-screen rotating drum filters are an alternative to sand filtration especially when excessive waste water is a concern. The filtering process of drum screen filters is very simple, yet very efficient and reliable due to their overall design and operation. Drum filters are designed with few moving parts to ensure a long life with low operating/ maintenance costs. Micro-screening essentially captures particles on a screen fabric while letting the water pass. This paper describes a design of two an industrial-scale drum screen filters driven by undershot wheel and its performance installed in recirculating aquaculture system culturing tilapia at El-Nenaeia fish farm. These filters are consisted of a woven metal mesh of 100 µm. The design criteria for solids loading rate in the influent water is 10 kg m-2min-1. The results indicate that the design parameters of the filter such as surface are and rotation speed were affected by the water flow rate, where the surface area and drum speed ranged from 1.58-27.87 m2, and 1.05-8.40, respectively. The results also indicated that the efficiency of filter decreased during the first two months compared to the last two months of fish growth period, with an average 34.22 ±8.85% during the first 60 days and an average 52.41 ±16.77 % during the last period. Using water wheels for driving the screen filter is very important in saving energy, where the filter with such dimensions needs 1.0 hp for driving it, which represents 18.0 kW daily
The prediction of aquaculture pond temperatures throughout the year is essential to the design an... more The prediction of aquaculture pond temperatures throughout the year is essential to the design and evaluation of potential aquaculture sites. An energy balance was developed for earthen aquaculture ponds to 1) determine the relative importance of energy transfer mechanisms affecting pond temperature; 2) predict pond temperatures, and 3) estimate the energy required to control pond temperatures. A computer program was developed to solve the energy balance using weather and pond temperature data. Initial simulations for aquaculture pond validated the model’s ability to predict pond temperature changes. The dominant energy transfer mechanisms for ponds were solar radiation, pond radiation and longwave sky radiation. Finally, management and design questions about the warm water aquaculture ponds, such as the pond temperature throughout an average weather year, the amount of energy needed to maintain the pond temperature constant and the amount of energy required to warm a pond from 10 to 28°C, were answered by additional simulations.
The performance of a model developed by Ali (2006) to simulate aquaculture pond temperature was e... more The performance of a model developed by Ali (2006) to simulate aquaculture pond temperature was evaluated using sensitivity analysis and the model verified with data from aquaculture pond. The sensitivity analysis showed that output varied linearly with changes in average air temperature and solar radiation. Results from model verification runs showed that the model performance was satisfactory with respect to aquaculture pond temperature. In the future, the model will be used to investigate the effects of aquaculture pond temperature on daily growth rate to obtain the weight of individual fish throughout the year
This paper aims to study the performance of using the airlift pump as a pumping and aeration syst... more This paper aims to study the performance of using the airlift pump as a pumping and aeration system in the aquacultural systems. Water flow rates, dissolved oxygen and temperature were measured, and standard aeration efficiencies (SAE) were determined in airlift pumps 5.0, 7.5 and 10.0cm in diameter, 0.5, 1.0 and 1.5m in length and submergence of airlifts were 70, 80 and 90% from pipe length to develop performance data that might be useful to aquaculturists. Air was injected through leaky pipes ( 13mm). The results indicated that, the water flow rate and standard aeration efficiency (SAE) increased with increasing of both length and diameter of airlift pumps and submergence ratio. The water flow rate increased with air injection until it reaches to the peak then it decreased. The standard aeration efficiency (SAE) increased in narrow range with increasing the air flow rate, after this range it decreased with increasing the air flow rate.
This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in t... more This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in the aquacultural systems. Air pressure in the pipe, standard oxygen transfer rate (SOTR), and standard aeration efficiency (SAE) were determined to evaluate the performance of these pipes under different air flow rates (14.1-106.0 m3/h) and water hydrostatic pressures (0.5-2.0 m H2O) for five and ten pipes on the line. The results indicated that the air pressure increased with increasing of both hydrostatic pressure and airflow rate. The effect of the hydrostatic pressure on the air pressure was higher than that of the air flow rate. The standard oxygen transfer rate (SOTR) increased with increasing the hydrostatic pressure in the aeration tank. Using ten leaky pipes on the air pipe caused an increase in the standard oxygen transfer rate (SOTR) compared to the use of five pipes treatment. The standard aeration efficiency (SAE) decreased with increasing the air flow rate. It could be concluded also that, the effect of air flow rate on the SAE is greater than that of the hydrostatic pressure. The results revealed also that the SAE increased with increasing the number of leaky pipes.
This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in t... more This paper aims to study the possibility of using the leaky pipes as a diffused-air aeration in the aquacultural systems. Air pressure in the pipe, standard oxygen transfer rate (SOTR), and standard aeration efficiency (SAE) were determined to evaluate the performance of these pipes under different air flow rates (14.1-106.0 m3/h) and water hydrostatic pressures (0.5-2.0 m H2O) for five and ten pipes on the line. The results indicated that the air pressure increased with increasing of both hydrostatic pressure and airflow rate. The effect of the hydrostatic pressure on the air pressure was higher than that of the air flow rate. The standard oxygen transfer rate (SOTR) increased with increasing the hydrostatic pressure in the aeration tank. Using ten leaky pipes on the air pipe caused an increase in the standard oxygen transfer rate (SOTR) compared to the use of five pipes treatment. The standard aeration efficiency (SAE) decreased with increasing the air flow rate. It could be concluded also that, the effect of air flow rate on the SAE is greater than that of the hydrostatic pressure. The results revealed also that the SAE increased with increasing the number of leaky pipes.
El-Nenaeia Company has developed a commercial fish production demonstration utilizing water recyc... more El-Nenaeia Company has developed a commercial fish production demonstration utilizing water recycle technology developed at Banha University, Faculty of Agriculture, Agricultural Engineering Department. The fish production system is designed in a 32.0 m long by 12.0 m wide. Fish production activities began in the spring of 1998. The facility is designed to produce 30 tons of fish annually, with the first crop being tilapia. The project is being operated as a public demonstration of this technology, with biological, engineering and economic data being collected by research personnel at El-Nenaeia Company. This paper outlines the design of the recirculating system technology used to recycle water through the main fish production tanks.
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Papers by Samir A Ali
intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and
storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different
protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk
density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish
feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface
area of pellets fish feed value ranged from 10.57 to 71.13 mm2. The volume of pellets fish feed 4.04 to 79.09 mm3. The weight of
100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m-3. The
durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51
to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish
feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing
load of pellets fish feed value ranged from 6.13 to 33.28 N.
stage. The components of the energy balance of the compost pile which include: heat gained (heat generation and
solar radiation) and heat lost (radiation, evaporation, convection, and conduction) at different ambient temperatures.
The model was able to predict the pile temperature at different ambient temperatures (15, 20, 25, 30 and 35°C) and
different airflow rates (0.7, 1.1 and 1.5 mg air s-1 kg-1 dry matter). The results showed that the pile temperature increases
with increasing ambient temperature and it decreases with increasing airflow rates, where, as the ambient temperature
increased from 15 to 35°C, the pile temperature increased from 33.40 to 37.41°C, and when the airflow rates increased
from 0.7 to 1.5 mg air s-1 kg-1 dry matter, the pile temperature decreased from 34.40 to 32.39°C. The pile temperature
increased slightly and reached a maximum value at day 14. It indicates that the net energy gained to the pile increases
with increasing ambient temperature, meanwhile, the heat lost decreases with increasing ambient temperature. The
model results indicated that the predicted daily temperature was in a reasonable agreement with those measured ones
and other data in literature (Barrena et al. and Ahn et al.) at different ambient temperatures and airflow rates, where,
it ranged from 30.30 to 73.40°C, while it was from 18.0 to 71.0°C experimentally during the whole period of compost
maturation.
gully to know the possibility of producing lettuce plants depending on the nutrients existing in effluent fish farm as
compared with the lettuce production using standard nutrient solutions. To achieve that was studied the effect of
source of nutrients (effluent fish water and nutrient solution), flow rate (1.0, 1.5 and 2.0 L min-1) and length of gully (2,
3 and 4 m) on the following parameters: nutrient uptake, dry weight and NO3-N content in plant. The obtained results
indicated that the fresh and dry weight of shoots increased in nutrient solution over those of effluent fish farm. The
fresh and dry weight of shoots decreased with increasing the flow rate and the length of gully. The dry weight of roots
increased in nutrient solution over those of effluent fish farm. The dry weight of roots decreased with increasing the
flow rate and the length of gully. The NO3-N content significantly increased in nutrient solution over those of effluent
fish farm. The NO3-N content decreased with increasing the flow rate and length of gully. The NO3/protein ratio
increased in nutrient solution over those of effluent fish farm.
Results from model verification runs showed that the model performance was satisfactory with respect to aquaculture pond dissolved oxygen. The relative percentage of error (RPE) for the 24 hours of simulation was 0.2818% and the correlation coefficient between predicted and measured dissolved oxygen was 0.97. The predicted dissolved oxygen was fluctuated between -0.101 to 0.113gO2m-3lower and higher than the measured dissolved oxygen for most of the 24 hour simulation.
The predicted results indicate that DO is affected by weather variables, especially solar radiation. The dissolved oxygen (DO) values ranged from 4.4 to 8.7 g m-3, where it reached the highest value (8.7) at 17:00 h, while it reached the lowest value (4.4) at 6:00 h.
The fish growth model results indicated that the total cycle time between the stocking and the harvesting is about 180-190 days during the summer months; compared with the total cycle time in natural setting is about 210-240 days
Micro-screening essentially captures particles on a screen fabric while letting the water pass. This paper describes a design of two an industrial-scale drum screen filters driven by undershot wheel and its performance installed in recirculating aquaculture system culturing tilapia at El-Nenaeia fish farm. These filters are consisted of a woven metal mesh of 100 µm. The design criteria for solids loading rate in the influent water is 10 kg m-2min-1.
The results indicate that the design parameters of the filter such as surface are and rotation speed were affected by the water flow rate, where the surface area and drum speed ranged from 1.58-27.87 m2, and 1.05-8.40, respectively. The results also indicated that the efficiency of filter decreased during the first two months compared to the last two months of fish growth period, with an average 34.22 ±8.85% during the first 60 days and an average 52.41 ±16.77 % during the last period. Using water wheels for driving the screen filter is very important in saving energy, where the filter with such dimensions needs 1.0 hp for driving it, which represents 18.0 kW daily
Initial simulations for aquaculture pond validated the model’s ability to predict pond temperature changes.
The dominant energy transfer mechanisms for ponds were solar radiation, pond radiation and longwave sky radiation.
Finally, management and design questions about the warm water aquaculture ponds, such as the pond temperature throughout an average weather year, the amount of energy needed to maintain the pond temperature constant and the amount of energy required to warm a pond from 10 to 28°C, were answered by additional simulations.
The results indicated that, the water flow rate and standard aeration efficiency (SAE) increased with increasing of both length and diameter of airlift pumps and submergence ratio. The water flow rate increased with air injection until it reaches to the peak then it decreased. The standard aeration efficiency (SAE) increased in narrow range with increasing the air flow rate, after this range it decreased with increasing the air flow rate.
intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and
storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different
protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk
density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish
feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface
area of pellets fish feed value ranged from 10.57 to 71.13 mm2. The volume of pellets fish feed 4.04 to 79.09 mm3. The weight of
100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m-3. The
durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51
to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish
feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing
load of pellets fish feed value ranged from 6.13 to 33.28 N.
stage. The components of the energy balance of the compost pile which include: heat gained (heat generation and
solar radiation) and heat lost (radiation, evaporation, convection, and conduction) at different ambient temperatures.
The model was able to predict the pile temperature at different ambient temperatures (15, 20, 25, 30 and 35°C) and
different airflow rates (0.7, 1.1 and 1.5 mg air s-1 kg-1 dry matter). The results showed that the pile temperature increases
with increasing ambient temperature and it decreases with increasing airflow rates, where, as the ambient temperature
increased from 15 to 35°C, the pile temperature increased from 33.40 to 37.41°C, and when the airflow rates increased
from 0.7 to 1.5 mg air s-1 kg-1 dry matter, the pile temperature decreased from 34.40 to 32.39°C. The pile temperature
increased slightly and reached a maximum value at day 14. It indicates that the net energy gained to the pile increases
with increasing ambient temperature, meanwhile, the heat lost decreases with increasing ambient temperature. The
model results indicated that the predicted daily temperature was in a reasonable agreement with those measured ones
and other data in literature (Barrena et al. and Ahn et al.) at different ambient temperatures and airflow rates, where,
it ranged from 30.30 to 73.40°C, while it was from 18.0 to 71.0°C experimentally during the whole period of compost
maturation.
gully to know the possibility of producing lettuce plants depending on the nutrients existing in effluent fish farm as
compared with the lettuce production using standard nutrient solutions. To achieve that was studied the effect of
source of nutrients (effluent fish water and nutrient solution), flow rate (1.0, 1.5 and 2.0 L min-1) and length of gully (2,
3 and 4 m) on the following parameters: nutrient uptake, dry weight and NO3-N content in plant. The obtained results
indicated that the fresh and dry weight of shoots increased in nutrient solution over those of effluent fish farm. The
fresh and dry weight of shoots decreased with increasing the flow rate and the length of gully. The dry weight of roots
increased in nutrient solution over those of effluent fish farm. The dry weight of roots decreased with increasing the
flow rate and the length of gully. The NO3-N content significantly increased in nutrient solution over those of effluent
fish farm. The NO3-N content decreased with increasing the flow rate and length of gully. The NO3/protein ratio
increased in nutrient solution over those of effluent fish farm.
Results from model verification runs showed that the model performance was satisfactory with respect to aquaculture pond dissolved oxygen. The relative percentage of error (RPE) for the 24 hours of simulation was 0.2818% and the correlation coefficient between predicted and measured dissolved oxygen was 0.97. The predicted dissolved oxygen was fluctuated between -0.101 to 0.113gO2m-3lower and higher than the measured dissolved oxygen for most of the 24 hour simulation.
The predicted results indicate that DO is affected by weather variables, especially solar radiation. The dissolved oxygen (DO) values ranged from 4.4 to 8.7 g m-3, where it reached the highest value (8.7) at 17:00 h, while it reached the lowest value (4.4) at 6:00 h.
The fish growth model results indicated that the total cycle time between the stocking and the harvesting is about 180-190 days during the summer months; compared with the total cycle time in natural setting is about 210-240 days
Micro-screening essentially captures particles on a screen fabric while letting the water pass. This paper describes a design of two an industrial-scale drum screen filters driven by undershot wheel and its performance installed in recirculating aquaculture system culturing tilapia at El-Nenaeia fish farm. These filters are consisted of a woven metal mesh of 100 µm. The design criteria for solids loading rate in the influent water is 10 kg m-2min-1.
The results indicate that the design parameters of the filter such as surface are and rotation speed were affected by the water flow rate, where the surface area and drum speed ranged from 1.58-27.87 m2, and 1.05-8.40, respectively. The results also indicated that the efficiency of filter decreased during the first two months compared to the last two months of fish growth period, with an average 34.22 ±8.85% during the first 60 days and an average 52.41 ±16.77 % during the last period. Using water wheels for driving the screen filter is very important in saving energy, where the filter with such dimensions needs 1.0 hp for driving it, which represents 18.0 kW daily
Initial simulations for aquaculture pond validated the model’s ability to predict pond temperature changes.
The dominant energy transfer mechanisms for ponds were solar radiation, pond radiation and longwave sky radiation.
Finally, management and design questions about the warm water aquaculture ponds, such as the pond temperature throughout an average weather year, the amount of energy needed to maintain the pond temperature constant and the amount of energy required to warm a pond from 10 to 28°C, were answered by additional simulations.
The results indicated that, the water flow rate and standard aeration efficiency (SAE) increased with increasing of both length and diameter of airlift pumps and submergence ratio. The water flow rate increased with air injection until it reaches to the peak then it decreased. The standard aeration efficiency (SAE) increased in narrow range with increasing the air flow rate, after this range it decreased with increasing the air flow rate.