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A STUDY OF EVAPORATIVE COOLING PAD PERFORMANCE FOR A PHOTOVOLTAIC POWERED GREENHOUSE
No full textThe performance of the fan and pad evaporative cooling system for a photovoltaic powered greenhouse was investigated under extreme summer conditions. Temperature, relative humidity and electricity consumed for cooling were studied in a Quonset greenhouse covered with a sheet of corrugated Fiberglass-Reinforced plastic producing cucumbers. Pads clogging due to salt buildup was found to reduce the cooling performance. Additionally pads clogging caused the cooling system to run at longer time, causing more power to be drawn from the photovoltaic system. As a result, the system tripped three times during the summer period for one to three days. During most of the daytime, the averages of inside air temperatures with clogged pads were between 30 and 51°C, and the inside relative humidity was between 8% and 30%. This adversely affected plant growth, and caused wilting to plants in the second half of the greenhouse especially when accompanied by high solar radiation levels (10:00 to 16:00). Shade reduced the stress on plants, but air temperatures and relative humidity were far from the suitable ranges for good production practice. On the average, temperatures with shade ranged from 40 to 47.5°C, and relative humidity ranged from 8 to 12%. Replacing pads clearly improved the greenhouse environment. Air temperature and relative humidity inside the greenhouse during daytime ranged from 28 to 32°C, and from 39.3 to 44%, respectively. The cooling efficiency for new pads was averaged 71%, with 8 to 17.3°C reductions in ambient temperature. Electricity consumption with new pads was found to be around 22% less than that with old pads. Results also showed that the electricity consumption increased non-linearly as the ambient temperature increased. The cooling system consumed the maximum level of electricity (2.7 and 3 kW) at ambient temperature of 37°C or higher suggesting that the cooling system was in full operation. Shade had very minimal effect on the electricity consumption for the greenhouse cooling system
EFFECT OF SOIL' PREPARATION ON THE PHYSICAL AND MECHANICAL PROlll!RTIES OF SUGAR BEET
No full textThe government is encouraging the farmers to grow sugar beet as an alternative of sugar crops production. The problems in sugar beet mechanization was the main effect of limiting the growing area of sugar beet as well as the handling of beets from field to factory.
In the present study, the effect of soil levelling; using laser and traditional leveller, on the physical and mechanical properties of sugar beet was studied. Two varieties of sugar beet were used (monogerm and muf tt-germ). The above factors were investigated in order to determine their effects on the physical dimensions of sugar beet plants, weight charac¬teristic of the plant portions, biological yield of plants, force required to pull the plant from soil, coefficient of static friction (sliding and rolling), and the cutting force required for topping the roots.
The mono-germ variety produced more root yields than the multi¬germ variety in the laser levelled soil by 17-19 %. In the loser levelled soil, the roots were rnorc uniforrn, had less height and bigger diameter. Also, required less root pulling force. The force requ'red to cut the root tops was depending on the thickness of the sheared layer and root diameter. The speed of the knife should be grenter than 2.8 m/s in order to get complete topping
EFFECTS OF TIRE SIZE AND PRESSURE ON TRACTIVE PERFORMANCE
No full textThe dynamic traction ratio and tractive efficiency were compared for a tractor equipped with 42-, 46-, and 54-inch rim diameter radial tires operating at 8, 12, and 18 psi inflation pressure. In general, lower drive wheel inflation pressure increased tractive performance. Also, the larger diameter tires perform better than the smaller tires on the firm surface
Apoptosis and advanced glycation end products (ages) in different types of diabetic retinopathy
No full textThis article was done to shed light on the pathogenesis of diabetic retinopathy with regard to its relation of the glycation end products (AGEs) indicated by serum fructosamine and glycosylated heamoglobin and apoptosis as indicated by the level of serum Apo1Fas. Forty-three patients with type II diabetic retinopathy were attending to the ophthalmic clinic of Research Institute of Ophthalmology. They were classified into four groups including: normal fundus (NF) 12 cases, non-proliferative diabetic retinopathy (NPDR) 12 cases, proliferative diabetic retinopathy (PDR) 10 cases, and maculopathy 9 cases. Eight subjects were selected to serve as control.
Fasting blood glucose (F.B.G.), serum fructosaminc, glycosylated heamoglobin (HbA1c), and serum Apol-Fas were estimated.
The data obtained showed that blood glucose level was significantly high in all groups (raining from 168.8±6.07 to 282.5±8.5 mg/dl) and HbAl1c level was also significantly higher than normal, its range between 8.71±0.29% in normal fundus group to 16.6±0.88% in proliferative group. There was a significant increase in the level of serum fructosamine particularly in the group of patients with maculopathy (P<0.006). There was also a positive correlation between Apo-1-Fas and fasting blood glucose (r = 0.514, p<0.0001); FbA1c (r = 0.477, p<0.0004); fructosamine ( r = 0.529, P<0.0006) for all diabetic groups. A positive correlation between age and apoptosis in normal fundus group (r = 902, P<0.0001), and in proliferative diabetic retinopathy ( r = 0.705, P<0.023) were observed.
It was concluded those patients are subjected to a state of active apoptosis indicated by increased serum Apo-1-Fas and enhanced formation of advanced glycation end products as proved by marked increase in serum fructosamine and glycosylated heamoglobin. These changes are suggested to contribute to retinal micro-vascular complications in diabetic patients. Control hyperglycemia is believed to minimize these hazards
SUSCEPTIBILITY OF CERTAIN CULTIVARS AND HYBRIDS OF BRASSICACEOUS AND CUCURBITACEOUS VEGETABLES TO MELOIDOGYNE JAVANICA IN SAUDI ARABIA
No full textA total of 20 brassicaceous and cucurbitaceous vegetable cultivars and hybrids, including two cabbages, three cauliflowers, one garden rocket, two radishes and one turnip, three cucumbers, three pumpkin, one snake cucumber, three sequash and one watermelon, were examined in the greenhouse for their susceptibility to the root knot nematode, Meloidogyne javanica (Treub) Chitw.
Determination of host susceptibility was based on the standards and parameters documented by the International Meloidogyne Project. Most of the tested cultivars were found to susceptible to moderately susceptible and good hosts, except for white radish which was resistant and poor host to the tested nematode. Susceptible cultivars were clearly damaged by the nematode infection and roots appeared to be heavily galled.
Gall index values of all tested cultivars were ranged from 2.0-5.0, whereas, reproduction factor (Rf) values and number of eggs per gram root were significantly (P ≤ 0.05) varied among tested cultivars. They were ranged from 0.156-65.5 and 114.0-27638.2, respectively, where the minimum values are recorded for white radish and maximum ones for squash cv. Masha’el F1
EVALUATION OF SOME INSECTICIDES FOR THE CONTROL OF THE POTATO TUBERWORMS PHTHORIMEA OPERCULELLA (ZELLER) ON TOMATO CROP IN AL KHARJ PROVINCE
No full textThe purpose of the present study evaluate the efficiency of some insecticides used to control the potato tuberworms Phthorimea operculella (Zeller), and to know the effect of infestation on the yield of tomato. The effect of misuse of insecticides in traditional farms was also followed. The best insecticides was cypermethrin, which reduced infestation by 85.5%, followed by Beta-cyfluthrin (67.3%). The results indicate the decrease in the efficiency of these insecticides due to misuse in those farms. There was similarity among the results of most of these insecticides, except for cypermethrin and Beta-cyfluthrin. The results also shows the presence of resistance among the population of this insect as a result of the misuse of insecticides in some traditional farms
Evaluation of some insecticides to control the potato tuberworms Phathorimaea operculella (Zeller) on tomato crop in Al-Kharj province.
No full textThe purpose of present study is to evaluate and to know the efficiency of some insecticides used to control the potato tuberworms Phathorimaea operculella (Zeller), and to know the effect of infestation on the yield of tomato, and to record the effect of the mis-use of insecticides in traditional farms. The best insecticide tested was cypermethrin , which reduced infestation by 85.5%, then Beta-cyfluthrin (67.3%). The results indicate the decrease in the efficiency of these insecticides. There was a similarity of the results of most of these insecticides , except for cypermethrin and Beta-cyfluthrin. Also, the results indicate the presence of resistance among the population of this insect as a result of the mis-use of insecticides in some traditional farms
The bivariate generalized linear failure rate distribution and its multivariate extension
No full textAbstract The two-parameter linear failure rate distribution has been used quite successfully to analyze lifetime data. Recently, a new three-parameter distribution, known as the generalized linear failure rate distribution, has been introduced by exponentiating the linear failure rate distribution. The generalized linear failure rate distribution is a very flexible lifetime distribution, and the probability density function of the generalized linear failure rate distribution can take different shapes. Its hazard function also can be increasing, decreasing and bathtub shaped. The main aim of this paper is to introduce a bivariate generalized linear failure rate distribution, whose marginals are generalized linear failure rate distributions. It is obtained using the same approach as was adopted to obtain the Marshall–Olkin bivariate exponential distribution. Different properties of this new distribution are established. The bivariate generalized linear failure rate distribution has five parameters and the maximum likelihood estimators are obtained using the EM algorithm. A data set is analyzed for illustrative purposes. Finally, some generalizations to the multivariate case are proposed
Multiple-Antibiotic Resistance and plasmid Profiles of Salmonella enteritidis Isolated from Retail Chicken Meats.
No full textAbstract A study was conducted to determine the prevalence, antibiotics resistant and plasmid patterns of Salmonella enteritidis on chicken meat samples. A total of 578 chicken meat samples were examined over a period of 2 years from different retail outlets of a residential area of Namakkal City, South India. S.enteritidis prevalence was recorded 92 of 578 (15.91%). Seasonal variations in the prevalence pattern were identified with, a higher prevalence during monsoon months (19.68%) followed by post-monsoon (17.61%) and premonsoon. Present finding revealed that S. enteritidis isolates recovered from retail raw meats are resistant to more than one antibiotics, including those commonly used antibiotics in poultry feed were erythromycin, ampicillin, kanamycin, cephalothin and tetracyclin. All the isolates exhibited Multiple Antibiotic Resistance (MAR) and more than one plasmid. The plasmid size ranged between 0.43 and 115 MDa. Prevalence of multiple antimicrobial resistances among these strains suggesting possible prior selection by use of antimicrobials in meat production
Optimal Production Pattern for Greenhouse Products: A Case Study of Astra Farms at Tabouk, Saudi Arabia
No full textThe study was to examine the production status and magnitude for the greenhouse farms of the ASTRA farm located in the Tabouk area of the Saudi northern region. This is made to determine the main features of the production patterns along with the utilized production methods in order to identify the optimum production plan for the ASTRA group of farms. Linear programming mathematical technique has been utilized to maximize profits for the various production activities. They are: tomato, cucumber, lettuce, carnation, chrysanthemum, and gypsophila. This optimization process required the estimation of the required resources such as labor, irrigation water, fertilizers, and pesticides for the above-mentioned crops. The study showed that the optimum production plan is the one which achieves an annual gross profit of 9.8 million riyals. That is to say, an increase of 40 percent over its equivalent of 1991. It is recommended that the cultivated areas of tomatoe, cucumber, and gypsophila should be reduced from 3,75, 2 and 0.9 hectares to 3.2, 1.95, and 0.08 hectares, respectively. On the other hand, the areas of carnation and chrysanthemum should be increased from 1.25 hectares to 1.6 hectares. Moreover, the shadow price of irrigation water and labor are estimated at 1540.8 and 1360 riyals, respectively. Sensitivity analysis showed that no change in the optimum plan would occur if gross profits changed without an upper limit and with a lower limit of 222.97,218.85, and 202.32 thousand riyals for tomatoes, carnation, and chrysanthemum, respectively. On the other hand, no change in the optimum plan would occur if gross profits for gypsophila changed with an upper limit of 283.35 thousand riyals. Moreover, changes in gross profits per hectare for cucumbers and lettuce are found to have no impact on the optimum production plan. In general, it is found that there is no wide range for resources changes without altering the optimum pla