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Empact of Discrete Multi-arc Rib Roughness on the Effective Efficiency of a Solar Air Heater
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Artificial roughness on the absorber plate of a Solar Air Heater (SAH) is a popular technique for increasing its effective efficiency. The study investigated the effect of geometrical parameters of discrete multi-arc ribs (DMAR) installed below the SAH absorber plate on the effective efficiency. The effects of major roughness factors, such as number of gaps (Ng = 1-4), rib pitch (p/e = 4-16), rib height (e/D = 0.018-0.045), gab width (wg/e = 0.5-2), angle of attack ( = 30-75), and Reynolds number (Re= 2000-20000) on the performance of a SAH are studied. The performance of the SAH is evaluated using a top-down iterative technique. The results show that as Re rises, SAH-effective DMAR's efficiency first ascends to a specified value of Re to attain the maximum values then falls. The useful energy gained via SAH-DMAR is higher by an average of12% when compared to smooth SAH. According to the findings, the effective efficiency of SAH-DMAR is 9.4% higher thanthat of smooth SAH. The maximum thermal efficiency of SAH-DMAR and smooth SAH is 81.1 % and 74.7 %, respectively.

Publication Date
Fri Aug 01 2025
Journal Name
مجلة كلية التربية الاساسية
The Effect of the inquiry wheel model on the chemical enlightenment of Second- Year intermediate School female Students
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The aim of the research was to know the effect of the inquiry wheel model on chemical enlightenment among second-grade middle school female students in government daytime middle and secondary schools. Umm AlQura Middle School was chosen by intentional selection to be its students as the research sample for the academic year (2024-2025). Two groups were chosen, one of which was the experimental group studying using the inquiry wheel model and the other the control group studying in the usual way. The equivalence of the two research groups was verified by a set of variables, which were (chronological age in months, previous information test, Raven's intelligence test, chemical enlightenment scale). As for the research tool, the researchers bu

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Publication Date
Mon Jan 23 2023
Journal Name
Pakistan Heart Journal
The Impact of Claus Meyer on Metacognitive Thinking and Learning the Skill of Defending the Court with Volleybal
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The study aimed to prepare a measure of metacognitive thinking commensurate with learning the skill, preparing educational units using the Claus Meyer model for metacognitive thinking, and learning the skill of defending the court in volleyball. To identify the effect of educational units using the model (and Claus Meyer) for metacognitive thinking and learning the skill of defending the court in volleyball. The two researchers used the experimental approach with the design of the experimental and control groups.The research community consisted of students of the second stage / College of Physical Education and Sports Sciences / University of Baghdad for the academic year 2021-2022, whose number is (385) st

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Publication Date
Wed Jun 30 2010
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Effect of the Forming Conditions in the Production of Gamma Alumina Catalyst Support on the Crushing Strength Property
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An investigation was conducted for the determination of the effects of the forming conditions in the production of Gamma Alumina catalyst support on the crushing strength property. Eight variables were studied , they are ;binder content which is the sodium silicate , Solvent content which is the water, speed of mixing , time of mixing, drying temperature , drying time , calcinations temperature and the calcinations time
Design of the experiments was made by using the response Surface method in Minitab 15 software which supply us 90 experiments .
The results of this investigation show that the crushing strength for the dried Gamma alumina extrudate was affected by the drying temperature and the drying time only and there is no inter

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Publication Date
Thu May 18 2023
Journal Name
College Of Islamic Sciences
The battle of Dumat al-Jandal And its impact on the era of prophecy And the righteous caliphate
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The research in Islamic history is considered a title for the glory of the nation and a mirror for the intellectual and mental maturity of the men of the Islamic state who played an important role in saving humanity from darkness to light and from ignorance to knowledge and to show their position in building the Islamic state, and to highlight the importance of their conquests of neighboring cities and the expansion of Islam, and for this reason they appear The importance of writing on the topic (The Battle of Dumat al-Jandal and its impact on the era of the Prophethood and the Rightly Guided Caliphate). The reason for choosing this topic was to show the status of Dumat al-Jandal and its importance in the Islamic state and its great role

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Publication Date
Wed Dec 30 2009
Journal Name
Iraqi Journal Of Physics
Study the Effect of the High Voltage on The preparation of Polyvinyl Alcohol/ Tio2 Nano Fiber by Electrospinning
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In this research we prepared nanofibers by electrospinning
from poly (Vinyl Alcohol) / TiO2. The spectrum of the solution
(Emission) was studied at 772 nm. Several process parameter were
Investigated as concentration of PVA, the effect of distance from
nozzle tip to the grounded collector (gap distance), and final the
effect of high voltage. We find the optimum condition to prepare a
narrow nanofibers is at concentration of PVA 16gm, the fiber has
20nm diameter

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Publication Date
Thu Dec 31 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The effect of Marketing costs on the profitability of insurance companies: applied research in the national insurance company
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The research aims to study the marketing costs in its various items, which are important costs as it specializes in tunnels on the marketing side through which the company's services are introduced to ensure that these services reach as many segments of society as possible, which serves the company's objectives and expand its business and increase its market share. As well as the definition of profitability and its relation to marketing costs in the portfolios of the national insurance company. The research hypothesis was formulated to study and analyze the relationship and impact between the marketing costs and profitability of the research sample company. The research sample was determined by the National General Insurance Comp

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Publication Date
Thu Feb 17 2022
Journal Name
Teikyo Medical Journal
Study the Effect of different doses of Rapamycin on the liver development in the Swiss Albino Mice Embryos
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The current study, which extended from February 2020 to June 2021 at the University of Thi- Qar\ College of Education for Pure Sciences, aimed to follow the changes in external morphological features at different Embryonic Developmental stages in pregnant mice treated with different doses of Rapamycin (Rapa). Use In this study, 32 pregnant mice were divided randomly into four groups, each of which had eight pregnant mice. Each group received different dose of Rapa via intraperitoneally injection at different gestation days until the end of the specified periods, whereas the control group received a DMSO. Mice were administered under the same circumstances and dosages were determined based on body weight, as specified in pharmaceutical const

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Publication Date
Sun May 08 2011
Journal Name
Journal Of Planner And Development
The Effect of the Natural and Cultural Environments Factors on the Architectural and Planning Characteristics of Sulaymaniyah Mosques
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Most of the mosques in the Islamic world fall under specific and known forms and patterns to a large extent, and such patterns have grown and evolved from the few basic and uniform models, but they changed slowly due to the impact with a mixture of changing functional requirements and cultural landscapes because of the variables of time and place to form patterns known and famous in this day across parts of the Islamic world and its borders. There was no exception to these patterns, but small numbers of mosques that were probably the result of personal experiences or improvisational resolutions, or in response to specific or temporary stimuli. However, the emergence of a specific pattern which does not belong to any of these patt

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Publication Date
Sat Feb 01 2020
Journal Name
Journal Of Economics And Administrative Sciences
The impact of green strategy formulation processes on the adoption of green strategy areas at the functional level
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The research aims at demonstrating the role of the formulation of the green strategy in adopting the areas of the green strategy at the level of jobs in the municipal institutions in the province of Babylon, specifically the Directorate of the municipality of Hilla. The most important areas related to the green strategy were highlighted directly or indirectly, after the indicators of environmental damage emerged from the actions of companies and institutions. The research included a sample size of 222 individual of municipal institutions with different job titles and specializations between the technical and administrative and different levels of academic achievement within the institutions within the Ministry of Construction, Ho

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Crossref
Publication Date
Tue Jul 01 2025
Journal Name
Journal Of Studies In Humanities And Educational Sciences
The Effect of the Needham Constructivist Model on the Achievement of Third Year Biology Department Students in the Subject of Teaching Methods
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The current research aims to know the effect of Needham's constructivist model on the achievement of third-year students in the Life Sciences Department in the teaching methods subject. To achieve the research objectives, the experimental method was followed for the experimental and control groups with dimensional measurement of the achievement variable of the teaching methods subject. The research sample included (62) students in the third year of the Life Sciences Department, distributed into two equal groups in the variables (self-assessment of learning methods - chronological age in years - intelligence level - previous information). To measure the level of students' achievement, an achievement test was constructed consisting of (40) te

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