Solar photovoltaic (PV) has many environmental benefits and it is considered to be a practical alternative to traditional energy generation. The electrical conversion efficiency of such systems is inherently limited due to the relatively high thermal resistance of the PV components. An approach for intensifying electrical and thermal production of air-type photovoltaic thermal (PVT) systems via applying a combination of fins and surface zigzags was proposed in this paper. This research study aims to apply three performance enhancers: case B, including internal fins; case C, back surface zigzags; and case D, combinations of fins and surface zigzags; whereas the baseline smooth duct represents case A. A 2D, steady-state simulation model that took into account the impact of the convective flow of air circulating inside the PVT system in addition to radiative and convective heat losses from the front PV surface was developed and validated via previous tests. The results revealed that, under the same volume requirements, the application of surface zigzags is preferred for airflow rates of 0.06 kg/s or less, whereas the introduction of fins is preferred for higher airflow rates. The results also revealed that, of the three cases considered, the introduction of the fin–surface zigzag combination is the most effective and has the potential to improve the electrical and thermal efficiency by ~26% and 3%, respectively.
Carbon fiber reinforced polymers (CFRP) were widely used in strengthening reinforced concrete members
in the last few years, these fibers consist mainly of high strength fibers which increase the member capacity in addition to changing the mode of failure of the reinforced concrete beams. Experimental and theoretical investigations were carried to find the behavior of reinforced concrete beams strengthened by CFRP in shear and bending. The experimental work included testing of 12 beams divided into 4 groups; each group contains 3 beams. The following parameters were taken into consideration: - Concrete crushing strength. - CFRP strengthening location (shear strengthening and both shear and flexure strengthening). Reinforced beams were
Inflammatory bowel disease includes both Crohn’s disease and ulcerative colitis, is a chronic, progressive relapsing disease of gastrointestinal tract that require long-term treatment or maintenance therapy. Taking patient’s beliefs about the prescribed medication in consideration had been shown to be an important factor that affects compliance of the patient in whom having positive beliefs is a prerequisite for better compliance. The aim of the current study was to investigate and assess beliefs about medicines among a sample of Iraqi patients with inflammatory bowel disease and to determine possible association between these beliefs and some patient-specific factors.
This study is a cross-sectional study carried out o
... Show MoreBackground: Diabetes mellitus is a metabolic disorder affecting people worldwide, which require constant monitoring of their glucose levels. Commonly employed procedures include collection of blood or urine samples causing discomfort to the patients. Necessity arises to find alternative non invasive technique is required to monitor glucose levels. Saliva is one of most abundant secretions in the human body and its collection is easy, noninvasive and painless technique. Objective: The aim of this study was to determine the efficacy of saliva as a diagnostic tool by study the correlation between blood and salivary glucose levels and glycosylated hemoglobin (HbA1c%) in diabetes and non diabetes, and the comparison of salivary glucose level
... Show MoreThis study aims to design unified electronic information system to manage students attendance in Lebanese French university/Erbil, as a system that simplifies the process of entering and counting the students absence, and generate absence reports to expel students who passed the acceptable limit of being absent, and by that we can replace the traditional way of using papers to count absence, with a complete electronically system for managing students attendance, in a way that makes the results accurate and unchangeable by the students.
In order to achieve the study's objectives, we designed an information syst
... Show MoreThis study was designed to investigate the hepatoprotective activity and antioxidant enzymes of purified Bauhinia variegate leaves extract and purified flowers extract were administered (200 mg/kg, orally once daily) to reduce the effect of carbon tetrachloride-damage in rat’sliver for three weeks. Thereafter, the levels of some serum biochemical factorssuch as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase,and the activity of three different antioxidant enzymes (glutathione, superoxide dismutase, and catalase) were investigated.Liver homogenate can used to estimated antioxidant parameters: glutathione, superoxide dismutase and catalase. The purified Bauhinia variegate leaves and purified flowers significantly
... Show MoreBackground: Saliva is one of the most important etiological host factors in relation to dental caries. It affects the carious process by its organic and inorganic constituents; in addition to its physiological functions as (flow rate, pH and buffer capacity). The aims of this study were to determine the concentrations of major elements (calcium and phosphorus) and trace elements (ferrous iron, nickel, chromium and aluminum) in saliva among a group of adolescent girls, and to explore the relation of these elements, flow rate and pH with dental caries. Material & Methods: The study group consisted of 25 girls with an age of 13-15 years old. Dental caries was diagnosed by both clinical and radiographical examinations following the criteria of
... Show MoreThe corrosion behavior of low carbon steel in washing water of crude oil solution has been studied potentiostatically at five temperatures in the range ( 303 –343 )K, at pH ( 4 ) and at pH (4,6,7,9,11 ) at (343K)..The corrosion potential shifted to more negative values with increasing temperature and the corrosion current density increased with increasing temperature, the corrosion current density (icorr) decreased with increasing pH in the rang ( 4 – 7 ) and it increased with increasing pH in the rang ( 9 – 11 ) at ( 343 K ), while the corrosion potential generally variation with increasing pH in the rang (4-11)at(343K. From the general results for this study can be seen that thermodynamic and kinetic function were
... Show MoreThe present research aims at identifying the effect of the cognitive discrepancy strategy on the fourth-stage students’ achievement in literature and texts. The researcher adopted the null hypothesis: there is no statistically significant difference at the level (0.05) between the average grades of the experimental group who study literature and texts following the discrepancies strategy, and those who follow the traditional method. A post-achievement test of (60) paragraphs was administered to (6) students as the study sample. The results showed that the experimental group who studied literature and texts with the strategy of cognitive achieved better than the control group who followed the traditional method in the post-achievement t
... Show Moreالخلاصة
تعد الانتخابات بمثابة الطريق المؤدي إلى الديمقراطية كونها النمط الأكثر شيوعاً لمشاركة المواطنين في الحياة السياسية للبلدان واختيار ممثليهم في المجالس التشريعية، حيث أن مطلب إجراء انتخابات حرة ونزيهة لم يعد مطلباً داخلياً فحسب بل مطلباً دولياً يصرّ المجتمع الدولي على الوفاء به وهذا يلقي على عاتق كل دولة أن تضع من الضمانات ما يكفل ممارسة هذه الانتخابات ب
... Show MoreThe research aims to identify the rates of hair loss during pregnancy and lactation and its relation to the rates get some elements motivator urged through the results of the continued failure to meet the need of daily assessments of these elements, which led to the continuation of Hair Loss