The design, construction and investigation of experimental study of two compound parabolic concentrators (CPCs) with tubular absorber have been presented. The performance of CPCs have been evaluated by using outdoor experimental measurements including the instantaneous thermal efficiency. The two CPCs are tested instantly by holding them on a common structure. Many tests are conducted in the present work by truncating one of them in three different levels. For each truncation the acceptance half angle (θc) was changed. Geometrically, the acceptance half angle for standard CPC is (26o). For the truncation levels for the other CPC 1, 2 and 3 the acceptance half angle were 20o, 26o and 59o, consequently. A significant difference between the instantaneous thermal efficiency of 3.86× CPC (θc=20o) and 2.32× CPC (θc=26o), and between that for 3.61× CPC (θc=26o) and 2.32× CPC (θc=26o). It's noticed that the difference between the instantaneous thermal efficiency of 2.32× CPC (θc=59o) and 2.32× CPC (θc=26o) is small compared with the difference of the first and second cases, the instantaneous thermal efficiency of 2.32× CPC (26o) was higher than those for other three CPCs. The experimental results show that the maximum thermal efficiency of the full 2.32×CPC (26o) is 0.708, the maximum thermal efficiency of the 3.93×CPC (15o), when it's truncated to 3.84× CPC (20o), 3.61× CPC (26o) and 2.32× CPC (59o) are 0.51, 0.52 and 0.66, respectively. As the concentration ratio decreases from (3.93× to 1×), the thermal efficiency, energy losses and optical efficiency increase from (0.47 to 63), (1.58 to 7.2 K.m2/W) and (0.494 to 0.797), respectively.
Background: Low-level laser therapy (LLLT) has been extensively applied to improve wound healing due to some biostimulatory properties presented by laser arrays apparently able to accelerate the repair of soft tissue injuries. However, the role of proinflammatory interlukines not been studied yet. IL_1 ? represent one of the most important poroinflammatory interlukines that involved in wound healing. The goal of this study was to investigate the effect of 790-805nm diode laser on the expression of IL_1 ? during wound healing in mice. Materials and Methods: Standard-sized wounds (1.5cm) were carried out in the face of 96 white albino mice. Half of them underwent LLLT treatment (360 J/cm 2) at 790-805 nm delivered immediately after wound pro
... Show More
(2)
The reuse or recycling of waste materials in different aspects of life is served the objective of sustainability and be beneficial to society. In recent years, a wide variety of waste materials were used in pavement construction. One of these materials is glass that generally produces in large quantities and crushed glass can be considered feasible alternative source of aggregate for asphalt mixture production. This study focused on examining the asphalt mixture properties of wearing course using crushed glass as fine aggregates. Fine crushed glass with various percentages by total weight retained on sieve 2.36 mm, 0.3 mm and 0.075 mm was used in the study. The results indicate that mixes containing crushed glass had lower Marshall stabilit
... Show MoreThe most important contemporary issues which related to the survey of the influence of communication development technology to land use sustainability. The research aims to explain the changes that happened in the quality & land use activities performance by understanding the transformations due to modern technology and its impact on current uses and its impact on changing functional relationships between those uses to create new combinations or hybrid uses.Research will follow the analytical descriptive approach in presenting the problem of research. Research has several conclusions & recommendations, one of conclusions is the change of the place concept and its relation to changing the concept of land use and its sustai
... Show MoreThis study focuses on evaluating the suitability of three interpolation methods in terms of their accuracy at climate data for some provinces of south of Iraq. Two data sets of maximum and minimum temperature in February 2008 from nine meteorological stations located in the south of Iraq using three interpolation methods. ArcGIS is used to produce the spatially distributed temperature data by using IDW, ordinary kriging, and spline. Four statistical methods are applied to analyze the results obtained from three interpolation methods. These methods are RMSE, RMSE as a percentage of the mean, Model efficiency (E) and Bias, which showed that the ordinary krigingis the best for this data from other methods by the results that have b
... Show More
(1)
The aim of this research is to find out the satisfaction functional for faculty members
To Girls College of education at the University of Baghdad, and to find out the differences in this variable according to gender and qualification of education.
The sample was chosen from 60 teachers (males – females), they applied a questionnaire consisting of (30) paragraphs after the verifying of sincerity and persistence for paragraphs.
The main findings of the studies,
The results are indicated that the samples (faculty members) have a good level of satisfaction functional. In addition, results are shown; there are no significant differences of statistically between males and females for the faculty members. However, results are sho
11-22 Description An apology may be defined as “the act of declaring one’s regret, remorse or sorrow for having insulted, failed, injured, harmed or wronged another (Internet Encyclopedia of Philosophy IEP). A definition quite interested in the function suggests that “an apology is a speech act addressed to B’s face–needs and intended to remedy an offence for which A. takes responsibility.”(Holmes, 1990: 159). Apologies are also" speech acts" that are hard to identify, define or categorize, a difficulty that arises directly out of the functions they perform (Lakoff, 2001: 201) and the forms they take. In function, they range from selfabasement for wrongdoing to the formal display of appropriate feeling. In form, they range from
... Show MoreAbstract The results of the effect of the type of feed showed a significant increase (P≤0.01) for palm fronds DM during the incubation period of 7, 14, 21 days, a high Mnp superiority in its incubation 14 days, and a significant superiority of Laccase in its incubation 21 days, while the effect of the enzyme concentration on DM was higher Significant at a concentration of 10% of the enzyme, and the interaction between the type of feed and the enzyme together showed a highly significant increase in the treated palm fronds Laccase and Lip in the incubation period of 7 days, and the treated palm fronds Mnp during incubation 14 days. %, 15% for the interaction between the type of coarse feed and the concentration of the enzyme
... Show More
Thin films of the blended solution of (NiPc/C60) on glass substrates were prepared by spin-coated method for three different ratios (100/1, 100/10 and 100/100). The effects of annealing temperature and C60 concentration on the optical properties of the samples were studied using the UV-Vis absorption spectroscopy and FTIR spectra. The optical absorption spectrum consists of two main bands, Q and B band, with maxima at about (602-632) nm and (700-730) nm for Q1 and Q2 respectively, and (340-375) nm for B band. The optical energy gap were determined from optical absorption spectra, The variation of optical energy gap with annealing temperature was nonsystematic and this may be due to the improvement in crystal structure for thin films. Whi
... Show More
The present study was conducted to determine histopathological changes caused by chronic effect of Nitrofurantoin(NFT) in The albino mice Testes. The Study included 40 mice were divided on the five groups: the first group taken distilled water and become control group . the remaining group which are exposure with NFT drug in concentration (100-150-200-250) mg / kg, respectively, Doses were given orally for a period (month and two months). The results of histopathological changes included occurrence of congestion in the blood vessel and degeneration of spermatogonia and aggregation of spermatids in the lumen of semineferous tubules and inhibition of spermatogensis process and decrease of sperm inside the lumen
... Show More
(1)