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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
Mon Jun 01 2020
Journal Name
Journal Of The College Of Languages (jcl)
Literature and Novel: Classical novel in comparison to New Novel By Alain Robbe - Grillet: L'Art et le Roman: Le Roman Traditionnel Face au Nouveau Roman Alain Robe- Grillet
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Modern French novel has gained a distinctive status in the history of French literature during the first half of the twentieth century. This is due to many factors including the new literary descriptive objective style adopted by novelists like Alain Robbe – Grillet that  has long been regarded as the outstanding writer of the nouveau roman, as well as its major spokesman, a representative writer and a leading theoretician of the new novel that has broken the classical rules of the one hero and evolved, through questioning the relationship of man and the world and  reevaluating the limits of contemporary fiction , into  creating a new form of narrative.

Résumé:

En vue de résu

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Publication Date
Thu Oct 02 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Study of salivary IgA concentrations, salivary flow rate in patients with β –thalassemia major in Missan Governorate
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Background: Beta-thalassemia major is the most common monogenic known disorder in the Middle East, characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic Individuals. This study aimed to evaluate salivary flow rate and salivary IgA in β-thalassemia major patients. Since many oral and systemic conditions manifest themselves as changes in the flow and composition of saliva the dental practitioner is advised to remain up-to-date with this issue. Materials and methods: The study samples consist of (60) subjects, patients group composed of (30) patients with β –thalassemia major, age rang (5-23) years and (30) healthy locking

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Publication Date
Tue Jan 31 2017
Journal Name
Journal Of Engineering
Studying the Adsorption of Lead from aqueous Solution using Local Adsorbent Material Produced from Waste Tires by Pyrolysis
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In this research a local adsorbent was prepared from waste tires using two-step pyrolysis method. In the carbonization process, nitrogen gas flow rate was 0.2L/min at carbonization temperature of 500ºC for 1h. The char products were then preceded to the activation process at 850°C under carbon dioxide (CO2) activation flow rate of 0.6L/min for 3h. The activation method produced local adsorbent material with a surface area and total pore volume as high as 118.59m2 /g and 0.1467cm3/g, respectively. The produced . local adsorbent (activated carbon) was used for adsorption of lead from aqueous solution. The continuous fixed bed column experiments were conducted. The adsorption capacity performance of prepared activated carbons in this work

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Publication Date
Sat Sep 30 2023
Journal Name
Al–bahith Al–a'alami
Trends in Media Discourse during International Crises: An Analytical Study of the US Withdrawal from the Nuclear Deal
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The research focuses on the withdrawal of the United States from the nuclear agreement signed between the permanent members of the United Nations Security Council and the Islamic Republic of Iran concerning its nuclear program. This withdrawal has caused disruption in the official media discourse of the concerned countries. Therefore, the main question can be posed: Are there differences in the positions of countries related to the nuclear agreement, as well as those countries affected by it, before and after the official withdrawal of the United States on May 8, 2018?
The research aims to shed light on the trends in media discourse of the countries that signed the nuclear agreement and those affected by it b

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Crossref
Publication Date
Sun Aug 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The effect of the environmental management system on the clean production strategy / case study in Middle Refineries Company
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The aim of this research is to measure and analyze the gap between the actual reality and the requirements of the environmental management system in the middle refineries company/refinery cycle according to ISO14001: 2015, as well as to measure the availability of a clean production strategy and test the relationship and impact between the availability of the requirements of the standard and a clean production strategy for the actual reality in the company.

The research problem was determined by the extent to which the requirements of the environmental management system are applied according to ISO14001: 2015 in the middle refineries company? To what extent are the required clean production strategies ava

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Publication Date
Thu Oct 02 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Estimation of the Bennett mandibular immediate side shift in Iraqi full mouth rehabilitation patients (An in vivo study)
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Background: Controversy exists concerning the presence and amount of the Bennett mandibular immediate side shift among patients and whether it is necessary to accommodate for it in adjustable articulators. The aim of this study was to register and calculate the amount of any immediate side shift (ISS) present in patients requiring full mouth rehabilitation. Materials and methods: 3- dimensional condylar movements of 50 Iraqi TMD-free patients were recorded using a stereographic fully adjustable articulator system during protrusion, left and right eccentric mandibular movements. Protrusive angles of each patient were verified to figure out the suitable fossa analog for each case. The thickness of each right and left premade fossa analog sele

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Publication Date
Sun Sep 27 2020
Journal Name
Iraqi National Journal Of Nursing Specialties
Effectiveness of an Educational Program on Nurses- midwives' Knowledge about Pain Management during Labor in Baghdad Maternity Hospitals
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Objectives: To assess nurses-midwives' knowledge about pain management during labor before and after implementation of educational program and to determine the effectiveness of educational program on nurses-midwives' knowledge about pain management during labor in Baghdad Maternity Hospitals.

Methodology: A quasi-experimental design has been conducted during the period of (February 27th 2019 through 2nd June 2019) on non-probability sample (purposive) consists of (44 Nurses/midwives') who are work in delivery room, the sample was exposed to pretest, educational program, posttest. The study was conducted in three Directories, (Baghdad Teaching Hospital) at medical city health

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Publication Date
Sat Jan 13 2018
Journal Name
Journal Of Engineering
Investigating the Influence of the Cerium loading in prepared Y zeolite from Iraqi kaolin on its Catalytic Performance
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In this study, the effects of different loading doses of cerium in the prepared NaY zeolite from Iraqi kaolin were investigated. Al-Duara  refinery atmospheric residue fluid catalytic cracking was selected as palpation reaction for testing the catalytic activity of cerium loading NaY zeolite.  The insertion of cerium in NaY zeolites has been synthesized by simple ion exchange methods. Three samples of modified zeolite Y have been obtained by replacing the sodium ions in the original sample with cerium and the weight percent added are 0.35, 0.64, and 1.06 respectively. The effects of cerium loading to zeolite Y in different weight percent on the cracking catalysts were studied by employing a laboratory fluidized

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Publication Date
Tue Aug 27 2024
Journal Name
Tem Journal
Preparing the Electrical Signal Data of the Heart by Performing Segmentation Based on the Neural Network U-Net
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Research on the automated extraction of essential data from an electrocardiography (ECG) recording has been a significant topic for a long time. The main focus of digital processing processes is to measure fiducial points that determine the beginning and end of the P, QRS, and T waves based on their waveform properties. The presence of unavoidable noise during ECG data collection and inherent physiological differences among individuals make it challenging to accurately identify these reference points, resulting in suboptimal performance. This is done through several primary stages that rely on the idea of preliminary processing of the ECG electrical signal through a set of steps (preparing raw data and converting them into files tha

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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Humoral immune factor changes in group of patients with Non-muscle invasive bladder cancer treated with intravesical therapy.
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