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.
Abstract: Narrow laser pulses have been essential sources in optical communication system. High data rate optical communication network system demands compressed laser source with unique optical property. In this work using pulsed duration (9) ns, peak power 1.2297mW, full width half maximum (FWHM) 286 pm, and wavelength center 1546.7 nm as compression laser source. Mach Zehnder interferometer (MZI) is built by considering two ways. First, polarization maintaining fiber (PMF) with 10 cm length is used to connect between laser source and fiber brag grating analysis (FBGA). Second, Nested Mach Zehnder interferometer (NMZI) was designed by using three PMFs with 10 cm length. These three Fibers are splicing to sing
... Show MoreThe non static chain is always the problem of static analysis so that explained some of theoretical work, the properties of statistical regression analysis to lose when using strings in statistic and gives the slope of an imaginary relation under consideration. chain is not static can become static by adding variable time to the multivariate analysis the factors to remove the general trend as well as variable placebo seasons to remove the effect of seasonal .convert the data to form exponential or logarithmic , in addition to using the difference repeated d is said in this case it integrated class d. Where the research contained in the theoretical side in parts in the first part the research methodology ha
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ى ىلإ يقيبطتلا وبناج يف ثحبلا ىعس دقو ،ةصاخلا ةيراجتلا ؼراصملا يف ؽيقدتلا فاجل ؿيكشت ( تمض ةنابتسا ةرامتسا ـيمصت متخم تاعاطق ىمع ؿماكلاب ايعاجرتسا ـتو فايبتسا ةرامتسا ) 36 ةف فم فإ :ايمىا فاك تاجاتنتسلاا فم ةعومجمل ثحبلا ؿصوت دقو ،ؽيقدتلا فاجل ؿمعب ةمص تاذو تامومعملاب ةقثلا زيزعتو ةيلاملا ريراقتلا ةدوج فامض يف اىرود وى ؽيقدتلا فاجمل ةميملا ـايملا ا يف يرادلإاو يلاملا ءادلأا طبض ةيممع ىمع سكعني هرودب يذلاو
... Show Moreيتناول هـذا البحث بالتحليل التفاعل و التنسيق بين السياستين الماليـة و النقديـة و اثر هذا التفاعل و التنسيق على الاستقـرار و النمـو الاقتصـادي، و كيف ان الآثار المالية للسياسة النقدية قد تحفز الإجراءات الخاصة بالسياسة النقدية و معالجة الآثـار الجانبيـة و طبيعـة التفاعل و الارتداد بين إجراءات كلتا السياستين و أثرهما في التـوازن الاقتصـادي العــام، و تم في ثنايا البحث توضيح مسوغات التنسيق و مدى ضرورة ذلك بهد
... Show Moreقياس وتحليل تأثير صدمات أسعار النفط الخام على راس المال البشري في العراق للمدة (1970 – 2021)
The research aims to build an educational program - learning, according to the concepts of renewable energy and nanotechnology And knowledge of its impact on the technological enlightenment when the third phase students in the Department of Chemistry, and to verify the goal and put the researcher null hypothesis the following: No Statistically significant difference at the level (0.05) between the average scores of the experimental group students who are studying material nanotechnology and renewable energy program Altalima- learning and the average score for the control group of students who are studying the same article the usual way in technological enlightenment. The search was limited to the third row in the Department of Chemistry,
... Show MoreInformation security in data storage and transmission is increasingly important. On the other hand, images are used in many procedures. Therefore, preventing unauthorized access to image data is crucial by encrypting images to protect sensitive data or privacy. The methods and algorithms for masking or encoding images vary from simple spatial-domain methods to frequency-domain methods, which are the most complex and reliable. In this paper, a new cryptographic system based on the random key generator hybridization methodology by taking advantage of the properties of Discrete Cosine Transform (DCT) to generate an indefinite set of random keys and taking advantage of the low-frequency region coefficients after the DCT stage to pass them to
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The objective of this in vivo study is to investigate the effects of 337.1 nm pulsed N2 laser on cellular immune response represented by lymphocyte transformation capacity and phagocytosis activity in laboratory animals. The samples include 60 adult male BALB/c mice, were divided into control group and experimental groups. The experimental groups were divided into two main groups according to the time period after N2 laser irradiation. Each group was divided into 9 subgroups which exposed to N2 laser radiation at different values of pulse repetition rates and exposure times. The results of immunological tests demonstrated that the exposure to 180 J/cm2 of N2 laser radiation induce adverse effect to cellular immune response. The results o
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