The fall angle of sun rays on the surface of a photovoltaic PV panel and its temperature is negatively affecting the panel electrical energy produced and efficiency. The fall angle problem was commonly solved by using a dual-axis solar tracker that continually maintains the panel orthogonally positioning to the sun rays all day long. This leads to maximum absorption for solar radiation necessary to produce maximum amount of energy and maintain high level of electrical efficiency. To solve the PV panel temperature problem, a Water-Flow Double Glazing WFDG technique has been introduced as a new cooling tool to reduce the panel temperature. In this paper, an integration design of the water glazing system with a dual-axis tracker has been accomplished and experimentally tested in order to enhance the PV panel efficiency, especially at hot climates. The proposed glazing system can simultaneously perform two functions, firstly, working as a cooling tool for reducing the stored heat in the PV panel during its work and secondly as an optical filter for sun light spectrum. Optimum design factors with their levels for the glazing system were calculated according to Taguchi method. Test experiments were carried out in Baghdad city on the 20th and 21st July 2016 on the tracker with and without using the WFDG system. The obtained results show that, the PV panel temperature with using the WFDG system was significantly dropped by 44% and its efficiency increased maximally by 36.6% at solar irradiance of 1213W/m2 as compared with conventional one.
This research aims to test the ability of glass waste powder to adsorb cadmium from aqueous solutions. The glass wastes were collected from the Glass Manufacturing Factory in Ramadi. The effect of concentration and reaction time on sorption was tested through a series of laboratory experiments. Four Cd concentrations (20, 40, 60, and 80) as each concentration was tested ten times for 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 min. Solid (glass wastes) to liquid was 2g to 30ml was fixed in each experiment where the total volume of the solution was 30ml. The pH, total dissolved salts and electrical conductivity were measured at 30ºC. The equilibrium concentration was determined at 25 minutes, thereafter it was noted that the sorption
... Show MoreAbstract Twenty Bacillus isolated were obtained from different sample food and water. Bacillus B1 isolated was the highest asparaginase producer, it was identified as a strain of B. subtilis. The highest production of asparaginase was observed when mineral salt medium containing 0.3% asparagen, pH 8 and incubated at 40°c for 24 hrs. B. subtilis B1 cells were immobilized by entrapment methods (calcium alginate and agar), and by adsorption on solid surface such as sawdust and cotton. The result showed that the immobilized cells by adsorption on sawdust was the best, the immobilized cell retained 88% of asparginase activity after 48h while free cell retained 65%. Cells immobilized by adsorption on sawdust was incubated at different temperatu
... Show MoreThe present research deals with the spatial variance analysis in Jwartadistrict and conducting a comparison on the spatial and seasonal changes of the vegetation cover between (2007-2013) in order to deduce the relationship between the vegetation density and the areas which are exposed to the risk of water erosion by using Plant Variation Index NDVI) C (coefficient and by using Satellite images of Landsat satellite which are taken in 2/7/2007 and Satellite images of Landsat satellite taken in 11/1/ 2013, the programs of remote sensitivity and the Geographic Information Systems.
The study reveals that there is a variance in the density of vegetation cover of the area under study betwee 2007 and 2013. Howev
... Show MoreThe interest in pre-service teacher training has become influential in teaching English as a foreign language, and the purpose of this training course is to prepare qualified teachers to teach effectively through the application of this technique by undergraduate students. This research aims to find out the effect of using the seven principles of good practice as a teaching technique on the fourth stage student-teachers’ performance at the College of Education for Women/University of Baghdad, during the academic year 2017-2018. The sample includes (60) students selected according to the stratified sampling method. The observational checklist used by the department to assess the student teachers’ performance during the practicum perio
... Show MoreThe city suffers from the weakness of the civil defense to provide services where there are clusters of residential Guy covered services for that requires the study of the geographic distribution of the civil defense centers in Baghdad care great because they take care of Protect the population and their own property and protect state institutions. Through a review of the problems faced it is expected that this study will help decision-makers to take appropriate steps to develop this service core
The research aims to know the effect of investment risks measured by the beta coefficient on the efficiency of stock pricing measured by the pricing error. The research was applied in the banks listed in the Iraq market for the period (2017-2020). That affects the value of the shares of the companies listed in it and the risks associated with it, as the risks are a dynamic process that changes over time depending on the variables that affect the general development of the economy, so these fluctuations should be taken into account to achieve maximizing returns and reducing risks and what is reflected in stock prices in the Iraqi markets Securities, through which the following question was asked: How does investment risk affect the efficienc
... Show MoreThe research was conducted in one of the fields of the Department of Plant Production in the desert region (tomato development project) affiliated with the Directorate of Agriculture of the Holy Karbala Governorate for the purpose of studying the effect of spraying the shoots of the Kohlrabi plant (hybrid) with the Nano biopolymer (Chitosan) and the Azotobacter bio inoculum on the roots of the plant seedlings in terms of growth indicators and yield for the autumn agricultural season. 2023-2024 ,The means were compared according to the Duncan multiple ranges test at significant to level of 0.05.with R.C.B.D . The first factor was spraying the shoots with Nano- Chitosan at a concentration of (0, 1, and 2) g L-1, two weeks after transplanting,
... Show MoreThe current research illustrates experimentally the effect of series and parallel connection (Z-I Configurations) of flat plate water solar collectors array on the thermal performance of closed loop solar heating system. The study includes the effect of changing the water flow rate on the thermal efficiency. The results show that, the collector's efficiency in series connection is higher than the parallel connection within flow rate level less than (100) ℓ/hr. Moreover, the collector efficiency in parallel connection of (I-Configurations) is more than the (Z- Configurations) with increasing the water flow rate .The maximum daily efficiency for parallel (I-Configurations) and (Z- Configurations) are (55%) and (51%) at w
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