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Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air
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Heat pipes and two‐phase thermosyphon systems are passive heat transfer systems that employ a two‐phase cycle of a working fluid within a completely sealed system. Consequently, heat exchangers based on heat pipes have low thermal resistance and high effective thermal conductivity, which can reach up to the order of (105 W/(m K)). In energy recovery systems where the two streams should be unmixed, such as airconditioning systems of biological laboratories and operating rooms in hospitals, heat pipe heat exchangers (HPHEs) are recommended. In this study, an experimental and theoretical study was carried out on the thermal performance of an air‐to‐air HPHE filled with two refrigerants as working fluids, R22 and R407c. The heat pipe heat exchanger used was composed of two rows of copper heat pipes in a staggered manner, with 11 pipes per row. Tests were conducted at different airflow rates of 0.14, 0.18, and 0.22m3/h, evaporator inlet‐air temperatures of 40, 44, and 50°C, filling ratios of 45%, 70%, and 100%, and ratios of heat capacity rate of the evaporator to condenser sections (Ce/Cc) of 1 and 1.5. For HPHE's steady‐state operation, a mathematical model for heat‐transfer performance was set and solved using MATLAB. Results illustrated that the heat transfer rate was in direct proportion with the evaporator inlet‐air temperature and flow rate. The highest HPHE's effectiveness was obtained at a 100% filling ratio and (Ce/Cc) of 1.5. The predicted and experimental values of condenser outletair temperature were in good agreement, with a maximum difference of 3%. HPHE's effectiveness was found to increase with the increase in evaporator inletair temperature and number of transfer units (NTU) and with the decrease in airflow rate, up to 33% and 20% for refrigerants R22 and R407c, respectively. Refrigerant R22 was the superior of the two refrigerants investigated.

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Publication Date
Fri Mar 10 2023
Journal Name
Indian Journal Of Physics
Describing the differential inelastic inverse mean free path of PMMA polymer with the Mermin–Belkacem-Sigmund model
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Publication Date
Sat Jan 02 2021
Journal Name
Journal Of The College Of Languages (jcl)
Some innovative word-formation processes in popular Internet texts in Russian and Arabic: Некоторые Инновационные словообразовательные процессы в популярных интернет-текстах в русском и арабском языках
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       The present article discusses innovative word-formation processes in Internet texts, the emergence of new derivative words, new affixes, word-formation models, and word-formation methods. Using several neologisms as an example, the article shows both the possibilities of Internet word-making process and the possibilities of studying a newly established work through Internet communication. The words selected for analysis can be attributed to the keywords of the current time. (In particular, the words included in the list of "Words of 2019") there are number of words formed by the suffix method, which is the traditional method of the Russian word formation. A negation of these words is usually made thro

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Publication Date
Tue Jun 30 2020
Journal Name
Journal Of Planner And Development
Real estate acquisition barrier and its impact on urban development projects" Study Area: Infrastructure project in the capital Baghdad (North East Sewage Line project AL khansaa)
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The increase the rates of natural growth, urbanization and continuous migration, this has generated constant pressure and, as a result, the capital city of Baghdad faces a number of challenges related to its urban environment, including the challenge of acquiring real estate.

 

 and this research examines the impact of these holdings, representing the main base from which the various projects originate Urban in all areas (economic, social, and recreational).

 

this leads us to the research problem of the obstacles that arise during the process of acquiring real estate to carry out development projects, and to achieve the objectives of research, namely (work to create a regulatory methodology

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Publication Date
Wed Apr 30 2025
Journal Name
Iraqi Journal Of Science
Determination of Cobalt(II) Ion in Various Selected Alloys via Utilizing Continous Flow Injection Analysis ((CFIA) (Nagham-Four Sources of White  Snow LED Arranged in Three Rows Corresponding to Three Detectors Analyzer) (NAG-4SX3-3D)) Analyzer at 0-180o Angle
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The research study focuses on the efficient and accurate detection and determination of cobalt ions. The detection method involves the formation of brilliant green aggregates with calcium hexacyanoferrate in the presence of nitric acid. (Nagham-four sources of white snow light-emitting diodes arranged in three rows corresponding to three detectors) (The NAG-4SX3-3D Analyzer is an optical, chemical, electronic, and detection tool that receives a cumulative signal (no amplification is required). The total distance travelled is 760 mm with regard to YZ(mV) - tsec (dmm). It was selected for its precise calculation of the energy transducer profile. The linear range for measuring cobalt (II) ions is 0.05 to 20 mM. For concentrations of 5

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Publication Date
Wed Jan 01 2014
Journal Name
Journal Of The College Of Languages (jcl)
EL ANÁLISIS DE ERRORES DEL LEÍSMO Y LAÍSMO EN EL PAPEL DIDÁCTICO PARA LOS ALUMNOS DEL DEPARTAMENTO ESPAÑOLEN LA FACULTAD DE LENGUAS EN IRAK Search Summary: The analysis of the mistakes of the personal pronouns in effect replaces him in the
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During the educational practices in the Spanish department at the Faculty of Languages ​​, University of Baghdad , we noticed that the personal pronouns in effect replaced by the direct and indirect characterized hardly be expressed , and the difficulty of her education.

Rationale: I chose this topic because the personal pronouns differ between the Spanish language and the Arabic language. We believe that this study may be useful not only for language teachers, but also for students, because it can contribute to a greater awareness of and correct weaknesses.

Objectives: To apply the model from which to address the problems in the use of personal pronouns Spanish , and the difference between effect of direct and indire

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Publication Date
Wed Apr 06 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Management using the Six Sigma approach to cost rationalization of activities : Application in the Iraqi mechanical carpet factory
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The textile industries play a prominent role in reviving the national economy, but they are currently suffering from several problems, including the high costs of their activities, the low quality of their production processes, and accordingly, the hexagonal diffraction approach came to help analyze production activities to determine which of them are the most expensive and do not have a benefit or cost greater than Its benefit as a result of waste and losses that accompany its implementation. And by applying to the Iraqi mechanical carpet factory, the research reached several conclusions, the most important of which is the presence of several sources of waste and loss, such as activities and operations that do not add value, whi

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Publication Date
Sat Mar 02 2019
Journal Name
World Heart Journal
Assessment of the Left Ventricular Mass (LVM) among Patients with Diabetes in Relation to Age Using Doppler Echocardiography
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Background: Diabetes mellitus a major factor that has adverse effects on the vascular system and the heart. It causes an increase in cardiac muscle thickness, resulting in decreased compliance and increased peripheral arterial stiffness. This study aims to assess the left ventricular mass (LVM) and left ventricular hemodynamic changes in diabetic patients measured by Doppler echocardiography. Patients and Methods: The study included 50 diabetic patients ranging in age between 25 and 80 years, (mean age: 54.1 ± 15.10, 19 males, 31 females) and 50 healthy subjects, aged 25 to 80 years (mean age: 48.52 ± 14.45, 11 males, 39 females). Doppler echocardiography was used to assess left ventricular function. The measurements included

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Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
easurement & Analyses costs of quality& effect in strategic performance: An Application research in construction industry– Saad public company
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Many economic entities working in multiple industrial fields suffer fromlow techniques in using modern administrative means in their works. The mostused tool in measuring required procedures is to adopt and use quality costs. inspite of complications and bronchial of operations in construction projects, Theresearcher was able to find a structure to quality costs according to traditionclassification (prevention, Appraisal, failure) which enables the calculation ofthese costs and then analyze results and setting standards which can beimplemented in evaluating strategic performance for targeted project. and theforge research in theoretical fly to quality and costs concerning it inconstruction section , as well as strategically performance a

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Publication Date
Tue Dec 22 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Measuring Operational Risk on according to International Requirements: An Applied Research in Bank of Baghdad- Private Shareholders Organization
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This research aims to study and evaluate the reality of the Iraqi banks in terms of how they cope with the risks of the banking business, specifically banking operational risks, and to develop a model integrated to define, identify, measure and mitigate the impact of these risks on according to the Basel Committee requirements II about the dangers of Alchgal.uchir major search to the presence of weak results in the Iraqi banks in understanding and defining and measuring operational risks and not hedged properly, which avoids those banks operating losses as well as the results show there is a shortage in the equation of capital adequacy applied by the Iraqi banks because of non-observance of the minimum capital required to counter the ris

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Publication Date
Sun Jan 27 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Impact dimensions the Training process of the in components intellectual capital: Exploratory search in the National Insurance Company
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The concept of training is no longer traditionally understood Limited organize traditional training courses, but has become a strategic choice in the investment and development of human resources system, attic trying to find the answer to the core problem of the study which

is the extent to which the training process, the traditional form that meets the needs of the company the development of intellectual capital.This research aimstostatementof the impact dimensions the training process(training role, support or top management , training programs, modern technology)of the in components Intellectual Capital(Human Capital, Structural Capital, Customer Capital) and provide the top management of the Company for the development of sci

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