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.
Abstract:
Musa son of Yaqoob son of Izra, the Spanish poet, linguist, and philosopher, was born in Granada. He has many poems representing types of poetry. Also, he had important books, such as "the Poetry of Israel" and "Contemplative Research". He is knowledgeable in both Hebrew and Arabic, because most of his books were written in Arabic and the then translated to Hebrew. It seemed that he was influenced by Arab poets, specifically Abo Firas, and borrowed many issues, such as comparison, repetition, exaggeration, etc. and included them in his poetry.
All know that Arabic literature clearly influenced Hebrew literature in the Spanish era. Ara
... Show MoreBackground: Tooth wear is one of the most common problems in the older dentate population which results from the interaction of three processes (attrition, abrasion and erosion) and it affects all societies, different age groups, and all cultures. This study was achieved to evaluate the prevalence and distribution of tooth wear among institutionalized residents in Baghdad city\ Iraq. Subjects and Methods: This survey was accomplished on four private and one governmental institution in Baghdad city. One-hundred twenty three (61 males, 62 females) aged 50-89 years were participated in this study. The diagnosis and recording of tooth wear were according to criteria of Smith and Knight. Results: The prevalence of tooth wear was 100% with a mean
... Show MoreIn this work a series of fourteen new compounds were synthesized. Compound [1] was formed from the reaction of 2-aminobenzothiazole and p-bromophenacyl bromide. Aldehyde group [2] was obtained from the reaction of compound [1] with pocl3 in presence of DMF and CHCl3 .After that shiff bases have been synthesized from the reaction of compound [2] with different aromatic amine to give new shiff bases [3- 5]. These new shiff bases have been reduced to their corresponding amine [6-8] by means of sodium borohydride. Then reaction of shiff bases [3-5] with phenyl isocyanate gives 3-cyclic lactam derivatives [9-11]. 3-cyclic Oxazepine derivatives [12-14] were obtained by reaction of shiff bases [3-5] with succinic anhydride. These new formed co
... Show MoreThe variables of quantitative and qualitative Population role in the economic development process and it was said the human center of development and population is the goal of development and its tool , and Iraq suffers from problems in the economic growth and the standard of living and development in general, and if I want him evolution and development sectors must pay for these demographic changes especially , to study and that invest Pmaasb in the interest of the man
The study of the demographic situation in Iraq and at the provincial level to track paths demographic change and its impact on the entry of Iraq to the demographic window due to the change in the age structure of the population and how to use them and invested well in
The first chapter the importance of research and need for education scientists see that the roots of the use of a specimen Wheatley in learning and teaching back to Grayson Wheatley, one of the largest supporters of a modern construction, which lay the groundwork for the specimen stage and the form in which it is. That was attributed to him, often called his name called while some educators based learning strategy on the issue. He sees the learner in this model make him a meaningful understanding of problems during his progress, thereby acting with his colleagues to find solutions to them in small groups. He
Borders Search: Search by students is determined by th
... Show MoreMany designs have been suggested for unipolar magnetic lenses based on changing the width of the inner bore and fixing the other geometrical parameters of the lens to improve the performance of unipolar magnetic lenses. The investigation of a study of each design included the calculation of its axial magnetic field the magnetization of the lens in addition to the magnetic flux density using the Finite Element Method (FEM) the Magnetic Electron Lenses Operation (MELOP) program version 1 at three different values of current density (6,4,2 A/mm2). As a result, the clearest values and behaviors were obtained at current density (2 A/mm2). it was found that the best magnetizing properties, the high
... Show MoreThe volatility of the financial markets and the oil market plays a major role in influencing macroeconomic activity, as well as the high interaction between the both markets and the remarkable sensitivity to their each other fluctuations which cause the undesirable impact on other economic sectors as an expected result due the mentioned interaction.
The study aimed to analyze the relationship between the volatility of the major US market indices represented by the DJIA index, S & P500, due to their comprehensiveness of the financial market, as they summarize the performance of the entire US market which is the largest economy in the world, as well as the difference in the calculation mechanism, and oi
... Show MoreThe aim of this paper is to introduce the concept of N and Nβ -closed sets in terms of neutrosophic topological spaces. Some of its properties are also discussed.
The Internet image retrieval is an interesting task that needs efforts from image processing and relationship structure analysis. In this paper, has been proposed compressed method when you need to send more than a photo via the internet based on image retrieval. First, face detection is implemented based on local binary patterns. The background is notice based on matching global self-similarities and compared it with the rest of the image backgrounds. The propose algorithm are link the gap between the present image indexing technology, developed in the pixel domain, and the fact that an increasing number of images stored on the computer are previously compressed by JPEG at the source. The similar images are found and send a few images inst
... Show MoreBackground: Obesity tends to appear in modern societies and constitutes a significant public health problem with an increased risk of cardiovascular diseases.
Objective: This study aims to determine the agreement between actual and perceived body image in the general population.
Methods: A descriptive cross-sectional study design was conducted with a sample size of 300. The data were collected from eight major populated areas of Northern district of Karachi Sindh with a period of six months (10th January 2020 to 21st June 2020). The Figure rating questionnaire scale (FRS) was applied to collect the demographic data and perception about body weight. Body mass index (BMI) used for ass
... Show More