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Absorber Diameter Effect on the Thermal Performance of Solar Steam Generator
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In this work, a convex lens concentrating solar collector is designed and manufactured locally by using 10 convex lenses (concentrator) of a diameter 10cm and one Copper absorber tube of a diameter 12.5mm and 1mm in thickness 1m length. Two axes manual Tracking system also constructed to track the sun continuously in two directions. The experiments are made on 17th of May 2015 in climatic conditions of Baghdad. The experimental data are fed to a computer program to solve the thermal performing equation, to find efficiency and actual useful energy. Then this data is used in numerical CFD software for three different absorber diameters (12.5 mm, 18.75 mm and 25 mm). From the results that obtained the maximum thermal efficiency for the collector of diameter 12.5mm equal to 82.3% is higher than that for the collector of 18.75 mm and 25 mm diameter. The maximum outlet temperature is found equal to (105C, 93.9C and 83.5C) for collector absorber diameter equal to (12.5 mm, 18.75mm and 25 mm) respectively. The maximum mass flow rate 0.53 kg/hr when the solar radiation intensity equal to 899 W/m2. The all-day collector efficiency varies with diameter and reaches to maximum value of (77.9%, 61.4% and 52.8) for collector diameter equal to (12.5 mm, 18.75mm and 25 mm) respectively.

 

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Publication Date
Wed Jan 01 2025
Journal Name
Modern Sport
Vertical Resistance and Its Relationship with Speed-Strength and Biomechanical Variables During the Takeoff Phase and the Performance of Selected Activities in Individual and Team Sports
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Jumping ability is a fundamental variable in many sports, as its execution requires an integration of muscular strength Q1 and certain biomechanical variables. This is particularly evident in gymnastics jumping events and jump shots in ball games, both of which rely on a high level of vertical resistance. Vertical resistance serves as an indicator of an athlete’s ability to overcome their body weight while counteracting gravitational force to achieve optimal performance. As such, it is considered one of the key factors in movements that demand explosive power and speed. The researchers believe that despite the significant relationship between vertical resistance, speed-strength of the arms and legs, and certain biomechanical varia

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Publication Date
Sat Jan 01 2022
Journal Name
International Journal Of Research In Social Sciences & Humanities
COLLABORATIVE WRITING AS A MEANS IN DEVELOPING EFL LEARNERS’ WRITING PERFORMANCE
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Collaborative learning is a way that prepares students practically for real-world applications. Working together as teamwork to execute various writing skills is essential in most professions since it increases the level of experience. Thus, the current study aims to identify the role collaborative writing in developing students' level of performance in writing. It is qualitative in nature since the researcher depended on the extant literature in achieving the objective of the study. The researcher touched upon related theories that addressed Collaborative learning, categories, and problems .It concluded that collaborative writing increases the students’ self-confidence, self-esteem, creativity, and motivation through the interact

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Publication Date
Wed Apr 05 2023
Journal Name
Journal Of Engineering
Performance Evaluation of Small Scale Air-Conditioning System Using R22 and Alternative Refrigerants
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A mathematical model has been formulated to predict the influence of high outdoor air temperature on the performance of small scale air - conditioning system using R22 and alternative refrigerants R290, R407C, R410A. All refrigerants were investigated in the cooling mode operation. The mathematical model results have been validated with experimental data extracted from split type air conditioner of 2 TR capacity. This entailed the construction of an experimental test rig which consists of four main parts. They are, the refrigeration system, psychrometric test facility, measuring instrumentation, and auxiliary systems. The conditioned air was maintained at 25 0C dry bulb and 19 0C wet bulb for all tests. The outdoor ambient air temperatur

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Publication Date
Fri Jul 10 2020
Journal Name
Int. J. Agricult. Stat. Sci
STUDY EVALUATION AND ANALYSIS OF THE PROPERTIES OF SOME PERFORMANCE STANDARDS FOR AGRICULTURAL TRACTOR AND SORGHUM BICOLOR (L.) MOENCH YIELD
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A field experiment was conducted in an agricultural field in Al-Hindia district, Karbala governorate in a silty clay soil during the year 2020. The research included a study of two factors, the first is the depth of plowing at two levels, namely 13 and 20 cm, which represented the main blocks. The second is the tire inflation pressure at two levels, namely (70 and 140 kPa), which represented the secondary blocks. Slippage percentage, field efficiency, leaf area, and 300 grain weight were studied. The experiment was carried out using a split-plot system under a Randomized complete block design, at three replications. The tillage depth of 13 cm exceeds/transcend by giving it the least slippage of (11.01%), the highest field efficiency of (50.

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Publication Date
Tue Dec 13 2022
Journal Name
Frontiers In Chemistry
Numerical analysis of the energy-storage performance of a PCM-based triplex-tube containment system equipped with arc-shaped fins
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This study numerically intends to evaluate the effects of arc-shaped fins on the melting capability of a triplex-tube confinement system filled with phase-change materials (PCMs). In contrast to situations with no fins, where PCM exhibits relatively poor heat response, in this study, the thermal performance is modified using novel arc-shaped fins with various circular angles and orientations compared with traditional rectangular fins. Several inline and staggered layouts are also assessed to maximize the fin’s efficacy. The effect of the nearby natural convection is further investigated by adding a fin to the bottom of the heat-storage domain. Additionally, the Reynolds number and temperature of the heat-transfer fluid (HTF) are e

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Performance Evaluation of Mobility Models over UDP Traffic Pattern for MANET Using NS-2
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  The current study presents the simulative study and evaluation of MANET mobility models over UDP traffic pattern to determine the effects of this traffic pattern on mobility models in MANET which is implemented in NS-2.35 according to various performance metri (Throughput, AED (Average End-2-end Delay), drop packets, NRL (Normalize Routing Load) and PDF (Packet Delivery Fraction)) with various parameters such as different velocities, different environment areas, different number of nodes,  different traffic rates, different traffic sources, different pause times and different simulation times .  A routing protocol.…was exploited AODV(Adhoc On demand Distance Vector) and RWP (Random Waypoint), GMM (Gauss Markov Model), RPGM (Refere

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Publication Date
Sat Dec 31 2022
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
EFFECT OF ORGANIC FERTILIZER SOURCRS AND CHEMICL FERTILIZATION ON SOME SOIL PHYSICL TRAITS AND YIELD OF SUMMER SQUASH (Cucurbta Pepo L.): EFFECT OF ORGANIC FERTILIZER SOURCRS AND CHEMICL FERTILIZATION ON SOME SOIL PHYSICL TRAITS AND YIELD OF SUMMER SQUASH (Cucurbta Pepo L.)
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ABSTRACT

            The results showed that the organic fertilizer mixture (1:1) 30 tons/ha with chemical fertilization recorded the lowest level of bulk density of 1.2 g/cm3, the organic fertilizer mixture (1:1) 30 tons/ha with chemical fertilization recorded the highest percentage of aggregation stability amounting to 16.17%, the organic fertilizer palm fronds recorded the highest level of ready water with an average of 5.50 cm3/cm3 and the organic fertilizer mixture (1:1) 30 tons/ha without chemical fertilization recorded the highest level of ready water as it reached 6.93%, the or

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Publication Date
Wed Jun 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Performance evaluation of small and medium-sized enterprises according to the entrance of the scorecard applied study in company Al fadly for construction industries
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The research Aim is to provide support to small enterprises by providing tools that enable measurement and test their performance and identifying weaknesses and work on them is determined by the problem of searching using traditional assessment methods for small projects with only financial performance measurement standards that do not provide a complete picture of the performance of these projects so use the balanced scorecard the four pillars (financial, customer, learning and growth, and internal processes) and identify deviations and work on them through the use of the outputs of the programme (probe), PROmoting Business Excellence-PROBE), which It is a model of performance evaluation, with which you can deve

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Publication Date
Sat Feb 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
EXTENSION ADMINISTRATION PERFORMANCE UNDER QUALITY STANDARDS FROM THE PERSPECTIVE OF THE WORKING STAFF IN AGRICULTURAL EXTENSION AND VEGETABLES FARMERS OF CENTRAL GOVERNORATES IN IRAQ
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This research aims to identify the level of extension administration performance under comprehensive quality standards from the perspective of the working staff in agricultural extension at the level of the general extension body and agricultural directorates and agricultural division.this was to identify the extension administration performance under comprehensive quality standards from the perspective of vegetables growers , random sample was selected from the central region governorates Baghdad , Diyala , Babel , karbala and Al-Najaf , a random sample from the workers in the general body numbered 56 employee , sample of staff working in agricultural extension was selected at the level of agricultural directorates in proportion

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Publication Date
Tue Jun 11 2019
Journal Name
Opicion
Assessing Students’ College of the Physical Education and Sport Sciences’ Level of Performance in English in Terms the New Prescribed Textbook “New Headway plus”
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