In this research an experimental study has done for testing the thermal performance of selective surfaces used in solar collectors for substrate of iron, galvanized iron and aluminum which are commercially available. The coating process for the samples has done in two ways, the electroplating and the chemical spray pyrolysis. The results of the thermal performance test of these samples are comparing with the thermal performance of a sample without paint and other paint with black paint without shines commercially available. For the electroplated samples, the performance study has done for different immersion time in plating bath, the
distance between electrical poles, the current density, and area ratio of the sample plated area to the nickel pole face area. The chemical sprayed pyrolysis samples, study has done for different coating times, atomizing gas pressures, distance between the aperture of atomizer and the sample and the paint mass flow rate. The results showed that the best performance of the iron's
samples is the sample which is coated with two layers. The first layer is of zinc done by electroplating where the time of plating is (2 min.) and the second layer is of black nickel done by electroplating, where the time is (20 min.), the distance between the poles is (6 cm), the current density is (0.15 A/dm2 ) and area ratio of the sample plated area to the nickel pole face area is equal to (1). The percentage of the increasing in heat storage of electroplating sample to galvanized iron sample without paint at the beginning of testing the performance of samples and at the end were (58.23%& 44.97%) respectively. For aluminum samples, the best performance was regarded for two samples electroplating sample and chemical spray pyrolysis sample. The best electroplating sample was coated with a layer of black nickel where the time of plating is (20 min.), the distance between the poles is (6 cm), the current density is (0.15 A/dm2) and area ratio of the sample plated area to the nickel pole face area is equal to (1). While the best chemical spray pyrolysis sample has been coated with a layer of black nickel where the time of plating is (16 sec.) and the distance between the aperture of the reservoir and the surface of the sample is (27 cm), the amount of flow is (4.8 ml / min.), the atomizing gas pressure is (1 bar) and temperature of the sample surface is (290 0C).
In the present work is the deposition of copper oxide using the pulsed laser deposition technique using Reactive Pulsed Laser as a Deposition technique (RPLD), 1.064μm, 7 nsec Q-switch Nd-YAG laser with 400 mJ/cm2 laser energy’s has been used to ablated high purity cupper target and deposited on the porous silicon substrates recorded and study the effect of rapid thermal annealing on the structural characteristics, morphological, electrical characteristics and properties of the solar cell. Results of AFM likelihood of improved absorption, thereby reducing the reflection compared with crystalline silicon surface. The results showed the characteristics of the solar cell and a clear improvement in the efficiency of the solar cell in the
... Show Morelar water heating systems with heat pipes of three diameter groups of 16, 22 and 28.5 mm. The first and third groups had evaporator lengths of 1150, 1300 and 1550 mm. The second group had an additional length of 1800 mm. all heat pipes were of fixed condenser length of 200 mm. Ethanol at 50% fill charge ratio of the evaporator volume was used as the heat pipes working fluid. Each heat pipe condenser section was inserted in a storage tank and the evaporator section inserted into an evacuated glass tube of the Owens- Illinois type. The combined heat pipe and evacuated glass tube form an active solar collector of a unique design.
The resulting ten solar water heating systems were tested outdoors under the meteorological conditions of Bag
Increasing the power conversion efficiency (PCE) of silicon solar cells by improving their junction properties or minimizing light reflection losses remains a major challenge. Extensive studies were carried out in order to develop an effective antireflection coating for monocrystalline solar cells. Here we report on the preparation of a nanostructured cerium oxide thin film by pulsed laser deposition (PLD) as an antireflection coating for silicon solar cell. The structural, optical, and electrical properties of a cerium oxide nanostructure film are investigated as a function of the number of laser pulses. The X-ray diffraction results reveal that the deposited cerium oxide films are crystalline in nature and have a cubic fluorite. The field
... Show MoreEnhancement of the performance for hybrid solar air conditioning system was presented in this paper. The refrigerant temperature leaving the condenser was controlled using three-way valve, this valve was installed after the compressor to regulate refrigerant flow rate towards the solar system. A control system using data logger, sensors and computer was proposed to set the opening valve ratio. The function of control program using LabVIEW software is to obtain a minimum refrigerant temperature from the condenser outlet to enhance the overall COP of the unit by increasing the degree of subcooled refrigerant. A variable load electrical heater with coiled pipe was used instead of the solar collector and the storage tank to simulate the sola
... Show MoreThe research problem boils question is there in Riyadh organizational climate that enables them to do their work properly and whether there are differences between the government and private Riyadh depending on the organizational climate has sought Find measure: 1 regulatory climate for kindergarten 2. The difference between government and private Riyadh depending on the organizational climate. Limited research on the (200) parameter of the Riyadh government and private parameters for the year (20,142,015) In order to achieve the research objectives the researchers built a regulatory climate in accordance with the scientific steps to build a psychological scales measure After the formulation of climate regulation paragraphs of the (30) p
... Show MoreThe research aims to measure the relationship and the impact of knowledge management processes to achieve the performance of insurance service, as well as analysis of the reality of the National Insurance Company to identify the level of overall performance, and to achieve this goal, it has been the selection of knowledge management processes according to the survey prepared a supplement to the study (Qubaisi, 2002), and of the four operations (knowledge generation, and storage of knowledge, and the distribution of knowledge, and application of knowledge), which represented the independent variable, and the performance has been the use of quantitative and qualitative measures, (sales growth, customer satisfaction), which represented the
... Show MoreThe aim of the research is to demonstrate the impact of organizational diversity management on achieving success, The problem of research is to create an appropriate work environment that stimulates everyone regardless of each dimension of diversity, So as to reach the best levels of success, The importance of research is to identify how the organization in question can manage organizational diversity effectively and contribute to its success, The research started from two main hypotheses which were derived from sub-hypotheses to identify the correlation and influence between the search variables by analyzing the answers of the research sample which included (81)
... Show MoreThe aim of the research is to provide an analytical study to promote financial inclusion in Iraq by clarifying the opportunities and challenges of the economic and demographic situation in Iraq, studying the structure of the financial system and introducing non-bank financial institutions operating in Iraq, and using the descriptive approach. Analytical in the study of the phenomenon of research, the research reached a number of conclusions, the most prominent of which were:
- Iraqi society is a young society.
- The majority of the population is 70 percent. They live almost in urban areas.
- The coverage of bank branch networks is concentrated in only four provinces, leaving other provinces outside financial
t: - Sports training in itself is a means, not an end. It is the core process that involves using exercises to provide an opportunity for athletes to perform their duties with the highest level of efficiency by developing and enhancing their capabilities and potential, using them to gain the greatest benefit for themselves and, consequently, for their team. This requires the selection of various methods and different means of training, focusing on specific physical and skill-related aspects. Therefore, training plans should take into account individual differences between players. Many researchers and experts in the field of sports in general, and combat sports in particular, emphasize the importance of having a holistic approach in the tra
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