The thermal and electrical performance of different designs of air based hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and lower surfaces of PV panels, air temperature, air flow rate, air pressure drop, wind speed, solar radiation and ambient temperature were measured. The power produced by solar cells is measured also. A theoretical model has been developed for the collector model IV based on energy balance principle. The prediction of the thermal and hydraulic performance was obtained for the fourth model of PV/T collector by developing a Matlab computer program to solve the numerical model. The experimental results show that the combined efficiency of model III is higher than that of models II and IV. The pressure drop of model III is less than that of models I and IV, by (43.67% and 49%). The average percentage error between the theoretical and experimental results was 9.67%.
Background: Determination of sex and estimation of stature from the skeleton is vital to medicolegal investigations. Skull is composed of hard tissue and is the best preserved part of skeleton after death, hence, in many cases it is the only available part for forensic examination. Lateral cephalogram is ideal for the skull examination as it gives details of various anatomical points in a single radiograph. This study was undertaken to evaluate the accuracy of digital cephalometric system as quick, easy and reproducible supplement tool in sex determination in Iraqi samples in different age range using certain linear and angular craniofacial measurements in predicting sex. Materials and Method The sample consisted of 113of true lateral cepha
... Show MoreThe stanza in the sonnet has been defined as a set of poetic lines followed after proem
and be the same meter as that of proem in complete stanza, but in rhyme scheme different
from that meter. The couplet is defined as set of poetic lines that followed the stanza and be as
the same meter as that of stanza, but with different rhyme scheme. This definition is approved
by all specialized in field of Andalus literature and it was also proven to them that this
construction emptied of indications. This meter has endeavored to prove that that there were a
difference in denotation for meaning between the stanza and couplet. Thus, the sonneteers
have outweighed the sonnet of the blind "Tutaili" to their sonnets as they felt
The Theoretical bases of women's rights in Islamic shariate
The cartographic representation of geographical phenomenon considers the essential base in geographical analysis since as it supports the vertical house which is apartment houses consist of apartments which represent civil phenomenon , the aim of this study is to project the rule of cartographic representation methods in geographical analysis and make comparison in economic and social aspects for two approaches , the vertical and construction building methods.
The expand of city horizontally represent a problem in itself because it leads to loss of civil lands and overpass the agricultural lands as a result ,the ratio of habitation of land usage is so large in comparison with another usages of lands of the cities ; therefore ; many co
In this study, measuring effectiveness Alauriz in some seeds powder and found that the seeds of-sophistication sex had the highest effective enzymatic reach 353 units / gProtein and Alkabbatah study enzyme extract under different storage conditions and Altaj showed that the enzyme loses Thbatih and whether Mrkbhetwan adding Alklasrin concentration of 10% for the systematic solution
This research deals with the technical configuration of the beautiful visions among Bany Ahmar poets reflected through the incarnation of beautiful artistic images that manifests itself clearly in the combination of two contradictories simultaneously.
The main conclusion is, the Andalusian poets try to use those fictional visions in search of aesthetic pleasure and values, through forming an image from water and fire as two prominent contradicted elements to express the impact of the heat of wine which soon vanishes when it is mixed with water. By this, they show the beautiful side of nature that suggests joy and splendor.
After the persistence of the British policy of oppression and control over the American colonies and the attempts to obliterate the identity of their inhabitants, the colonies worked on moving forward towards achieving independence, and Virginia was the first to initiate the development of the new government frameworks, through George Mason in drafting the Virginia Bill of Rights in 1776, which expressed the philosophy of the era Enlightenment and independent revolutionary thought, which called for equality and natural rights for individuals and the need for a free popular government that works for the common good.
This research aims to solve the nonlinear model formulated in a system of differential equations with an initial value problem (IVP) represented in COVID-19 mathematical epidemiology model as an application using new approach: Approximate Shrunken are proposed to solve such model under investigation, which combines classic numerical method and numerical simulation techniques in an effective statistical form which is shrunken estimation formula. Two numerical simulation methods are used firstly to solve this model: Mean Monte Carlo Runge-Kutta and Mean Latin Hypercube Runge-Kutta Methods. Then two approximate simulation methods are proposed to solve the current study. The results of the proposed approximate shrunken methods and the numerical
... Show MoreIn the present work theoretical relations are derived for the efficiency evaluation for the generation of the third and the fourth harmonics u$ing crystal cascading configuration. These relations can be applied to a wide class of nonlinear optical materials. Calculations are made for beta barium borate (BBO) crystal with ruby laser /.=694.3 nm . The case study involves producing the third harmonics at X. =231.4 nm of the fundamental beam. The formula of efficiency involves many parameters, which can be changed to enhance the efficiency. The results showed that the behavior of the efficiency is not linear with the crystal length. It is found that the efficiency increases when the input power increases. 'I'he walk-off length is calculated for
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