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Effect of Different Compressor Speeds on the Energy and Exergy of an Automobile Air-Conditioner Using R134a in the Absence and Presence of a Liquid-Suction Heat Exchanger
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Refrigerant R134a has been widely utilized in automotive air conditioning systems (AACSs); R134a has a high global warming potential (GWP) of 1430 despite having zero ozone depletion potential (ODP). Coming refrigeration systems must include refrigerants with low GWP and zero ODP. The aim of this experimental study is to evaluate the thermal performance of an (AAC) with different values of compressor speeds, i.e., (1000, 1700, and 2400 rpm) and two thermal loads, i.e., (500 and 1000 Watt) with the absence and presence of liquid suction heat exchanger (LSHX) using R134a. The results showed that adding LSHX enhanced the COP cycle by 7.18%, 10.7%, and 3.09% for the first, second, and third speed, respectively, at 500 Watt, while the enhancements were 10.27 %, 23.3 %, and 11.5 % for the first, second, and third speed, respectively, at 1000 Watt. Increasing the compressor speed decreased COP due to a reduction in RE and increased the compression effect, increasing the work done by the motor on the compressor that caused a reduction in COP. The compressor exergy destruction (X des. Comp.) decreased when LSHX was added by 6.13%, 2.22%, and 18.8% for the first, second, and third speed, respectively. However, X des. comp. increased with compressor speed due to the system’s pressure difference rise because of decreasing evaporation and increasing condensation pressures. As a result, the entropy generation increased. The increase in discharge temperature and pressure of the compressor led to a high friction force between the moving part of the compressor and the refrigerant, so the energy losses increased. Increasing the compressor speed decreased the total exergy performance of the cycle by 5.8 %, 7.5 %, and 16.7 % for the first, second, and third speed, respectively, due to increasing the compressor discharge temperature, increasing the X des. comp. and thermostatic expansion device and decreasing condenser and evaporator. Increasing X des. comp was higher than the destruction in the condenser and evaporator, which canceled the effect of others, so the total exergy performance of the cycle decreased.

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Publication Date
Sat Jan 03 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Effect of gender, age and tooth loss on the dimensions of incisive canal, and buccal bone anterior to the canal (Computed Tomography study)
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Background: The incisive canal is an anatomical structure with an important location in the anterior maxilla, analyzing this canal and its relation to the bone anterior to the canal is necessary during dental implant. Aim of this study is evaluated effect of gender, age and tooth loss in area of maxillary central incisors teeth on the dimensions of incisive canal and buccal bone anterior to the canal using spiral computed tomography. Materials and Methods: Sample consists of prospective study for 156 subjects for both gender, they divided into two groups, 120 dentate group (60 male and 60 female) with age ranging from (20-70) and 36 edentate group (with missing maxillary central incisors) (18 male and 18 female) with age ranging from (50-70

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Publication Date
Tue Jan 01 2019
Journal Name
Aip Conference Proceedings
Studying the partial substitution of barium with cadmium oxide and its effect on the electrical and structural properties of HgBa2Ca2Cu3O8+δ superconducting compound
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Publication Date
Mon Jan 01 2024
Journal Name
Journal Of Stomatology
The effect of Winter’s red line, angle of impaction, and radio-morphometric indices on surgical difficulty of impacted mandibular third molar: a prospective observational study
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Publication Date
Tue Oct 23 2018
Journal Name
Journal Of Economics And Administrative Sciences
“The impact of using the of the Government Finance Statistics Manual (GFSM) on The General Budget in Iraq”
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This research is aiming  to analyze the impacts of the current budget in Iraq by using  the Government Finance Statistics Manual (GFSM) , the research is based on hypothesis: (There is an impact on the using of the Government Finance Statistics Manual (GFSM) In public budget in Iraq) .This hypothesis was demonstrated by using the questionnaire, a number of conclusions were reached, the most important being the lack of terminology adopted in the government accounting system and the Iraqi financial and accounting manual as a result of their adoption of the monetary basis for the lack of accounting terminology that meets t

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Publication Date
Tue Oct 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
The Relationship Between The Internal Marketing and Quality Services : a Filed Study on Samples of Customers and Employees In Iraqi Commercial Banks
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Abstract

The Paper highlights on one of the main activities in marketing management. That is the internal marketing in the commercial banks and its relationship with the quality services offered to satisfy customers needs and wishes in order to reach he ultimate objectives of those banks. Two state and five private banks in Basrah city (Iraq) were taken in a field study. The survey covered the opinions of (184) state bank employees and (158) clients . The analysis of the survey shows that there is a strong relationship between the internal marketing ( in the banks covered by the survey) and the quality of banking objective services and the private banks show greater interest and concern to the internal ma

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Publication Date
Fri Mar 01 2019
Journal Name
Iraqi Journal Of Physics
Influence of working pressure and lasing energy of Al plasma in laser-induced breakdown spectroscopy
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Aluminum plasma was generated by the irradiation of the target
with Nd: YAG laser operated at a wavelength of 1064 nm. The
effect of laser power density and the working pressure on spectral
lines generating by laser ablation, were detected by using optical
spectroscopy. The electron density was measured using the Stark
broadening of aluminum lines and the electron temperature by
Boltzmann plot method it is one of the methods that are used. The
electron temperature Te, electron density ne, plasma frequency
and Debye length increased with increasing the laser peak
power. The electron temperature decrease with increasing gas
pressure.

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Publication Date
Thu Nov 19 2020
Journal Name
Indonesian Journal Of Chemistry
Determination of Eugenol in Personal-Care Products by Dispersive Liquid-Liquid Microextraction Followed by Spectrophotometry Using <i>p</i>-Amino-<i>N,N</i>-dimethylaniline as a Derivatizing Agent
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Two simple methods for the determination of eugenol were developed. The first depends on the oxidative coupling of eugenol with p-amino-N,N-dimethylaniline (PADA) in the presence of K3[Fe(CN)6]. A linear regression calibration plot for eugenol was constructed at 600 nm, within a concentration range of 0.25-2.50 μg.mL–1 and a correlation coefficient (r) value of 0.9988. The limits of detection (LOD) and quantitation (LOQ) were 0.086 and 0.284 μg.mL–1, respectively. The second method is based on the dispersive liquid-liquid microextraction of the derivatized oxidative coupling product of eugenol with PADA. Under the optimized extraction procedure, the extracted colored product was determined spectrophotometrically at 618 nm. A l

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Publication Date
Sat Jan 01 2022
Journal Name
Annals Of Biology
The Comparative Effect of Copper Oxide Nanoparticles and Copper Sulfate on Reproductive Hormones and Sperm Parameters in Mature Male Albino Mice
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Scopus
Publication Date
Thu Apr 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
Towards building an educational system free of scientific corruption (Applied study in a sample of colleges of higher education in Iraq within the framework of the government program and the directions of the Supreme Council for Combating Corruption)
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Nations are developed with education and knowledge that raise the status of society in its various segments, beyond that it leads to underdevelopment and deterioration in various sectors, whether economic, health, social, etc. If we considered the general name of The ministry of Education & Scientific Studies, then the second part seems to be not functioning, since scientific research has no material allocation and remains based on the material potential of the university professor. As for the first half of the topic, the reality of the situation reveals problems related to the Holy Trinity of Education which is (Professor - Student - the scientific method) where universities suffer at the present time from this problem, and

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Publication Date
Sun Apr 20 2025
Journal Name
Ihjpas
Synthesis, Characterization, and Study of Liquid Crystals Properties of New Five Heterocyclic Compounds
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Heterocyclic compounds are employed in many applications, and numerous researchers have created liquid crystals by adding heterocyclic to the structures of these molecules. This work includes the synthesis and characterization of new compounds that contain 5H-thiazolo [4,3-b][1,3,4] thiadiazol united in multiple steps, starting with the synthesis of the aldehyde compound [I] by reaction chloro ethyl acetate with 4-hydroxybenzaldehyde in the presence of ethanol and potassium carbonate, followed by reactions with thiosemicarbazide, mercapto acetic acid in sulphuric acid to produce compound [II] then reflux compound [II] with hydrazine hydrate to product compound [III], after that reaction the later compound with nalkoxybenzaldehyde [IV]n and

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