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.
Background: occult blood loss must be considered as a
possible cause in every case of iron deficiency anemia.
Objective: to evaluate upper gastrointestinal endoscopy
in finding a potential cause for iron deficiency anemia
among children in Al-Anbar governorate.
Methods: Twenty five children aged 2-14 years, referred
to the gastroenterology unit in Al-Ramadi General Hospital
for upper gastrointestinal endoscopy had iron deficiency
anemia. Fiberoptic endoscopy was used under general
anesthesia and endoscopic tissue biopsies were taken from
22 patients for histopathological examination.
Results: The main presenting signs and symptoms were
pallor, abdominal pain, and stunting. The upper
gastrointestinal
Polymers, being one of the most important materials in dentistry, offer great physical and mechanical qualities, as well as good biocompatibility. Aim of this study was done to evaluate the Polyetherketoneketone and Polyetherketoneketone polymer composite material used as dental implant through tensile strength, Fourier Transform Infrared analysis FTIR, and wettability). Polyetherketoneketone composites (Polyetherketoneketone and Strontium-containing hydroxyapatite) with selected weight percentage ratios of (0, 10%, 20%, 30%), were fabricated using a compression molding technique”, The study involved Samples preparation (sheets) shaped and form into the desired shape according to standard for tests which included tensile strength,
... Show MoreThis paper examines the impact of flexural strengthening on the percentage of damaged strands in internally unbonded tendons in partially prestressed concrete beams (0, 14.28%, and 28.57%) and the recovering conditions using CFRP composite longitudinal laminates at the soffit, and end anchorage U-wrap sheets to restore the original flexural capacity and mitigate the delamination of the soffit of longitudinal Carbon Fiber Reinforced Polymer (CFRP) laminates. The composition of the laminates and anchors affected the stress of the CFRP, the failure mode, and thus the behavior of the beam. The experimental results revealed that the usage of CFRP laminates has a considerable impact on strand strain, particularly when anchors are employed
... Show MoreThe present study is concern with the interaction between the naidid worms diversity and the species of aquatic plant within which the worms found . For this purpose, two species of aquatic plant were used, Ceratophyllum demersum and Eichhornia crassipes. 12 samples of aquatic plants were collected , as one sample monthly for a period from September 2012 to September 2013 from different site on Tigris river within Baghdad City. From C. demersum, 1428 individuals, were sorted during the study period, related to 17 species. 12 species of subfamily Naidinae which are Chaetogaster limnaei , C. diastrophus , Ophidonais serpentine , Dero ( Dero) digitata. , D.(D.) evelinae , Nais pseudobtosa , N.simplex, N.stolci , N.Paradalis , N.elingiu
... Show More