Preferred Language
Articles
/
joe-632
Exergy Analysis of a Domestic Refrigerator
...Show More Authors

An energy and exergy thermodynamic analysis using EES program was done for a domestic refrigerator working with R-134a using vapor compression refrigeration cycle. The analysis deals with the system component, i.e. compressor, condenser, evaporator and the expansion device. The analysis depends on the entropy generation minimization approach to improve the refrigerator performance by exploring the optimum design points. These design points were derived from three different theories governing the entropy generation minimization using exergy analyzing method. These theories were first applied to find the optimum balance between the hot inner condenser area and the cold inner evaporator area of the refrigerator and between its hot and cold thermal conductances. Nine types of condensers were used according to its internal surface area and thermal conductance, in order to reach the minimum entropy generation in the refrigerator. The results showed that the compressor has the lowest exergy efficiency of 25%. The expansion device was the second component after the compressor with exergy efficiency of 92%, followed by the condenser with an efficiency of 93%. The evaporator was found to have an exergy efficiency of 98 %. The experimental tests were repeated for the nine condensers sizes with three different ambient temperatures 25℃, 30℃ and 35℃.  The exergy analysis showed that the design of the refrigerator mainly depends on thermal conductance calculations rather than the surface inner area estimation.

 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Dec 30 2021
Journal Name
Al-kindy College Medical Journal
Assessment of the Depression Level among Medical Students at University of Baghdad, College of Medicine
...Show More Authors

Background: Depression, a state of low mood and aversion to activity, can affect people's thoughts, behavior, tendencies, feelings, and sense of well-being. It can either be short-term or long-term, depending on the severity of the person's condition. Risk factors include personal or family history of depression, major life changes, trauma, stress, certain physical illnesses, and medications.

Objective: This study investigates the prevalence of depression among medical students at the University of Baghdad, college of medicine in Iraq, and the association between some variables and depression.

Subjects and Methods: A cross-sectional study design with a convenience sampling method was conducted.

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Wed Dec 12 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Stress and Its Associated Factors among Students of the College of Nursing University of Baghdad
...Show More Authors

Objectives: The current study aims at identifying the level of perceived stress among nursing college students and determining the factors associated with stress they have. Methodology: A cross-sectional descriptive study initiated for the period on November 1st, 2014 to May 1st, 2015. The study has been conducted on the undergraduate nursing college students / University of Baghdad. The sample of the study was consisted of (128) students who were selected purposively. The questionnaire of the study was adopted and modified for the present study which consisted of socio-demographic data and the scale of

... Show More
View Publication Preview PDF
Publication Date
Mon Sep 03 2018
Journal Name
Al-academy
The privacy of the interior design of art education spaces in the schools of excellence
...Show More Authors

The current research deals with the specificity of the interior design of the classes of art education in the schools of excellence for the province of Muthanna and its center of the city of Samawah. In the first chapter، the problem of research was determined by the lack of internal spaces of the classes of art education to designs that meet the requirements and needs of students in these educational stages.  The importance of the research in being an addition to knowledge in the field of interior design and engineering department of the general directorates of the Ministry of Education. The objectives of the research were determined through.

  1. Identifying the reality of the halls of art education for sch

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Jul 01 2021
Journal Name
European Journal Of Dentistry
Effects of Long Durations of RF–Magnetron Sputtering Deposition of Hydroxyapatite on Titanium Dental Implants
...Show More Authors

Objectives Dental implant is a revolution in dentistry; some shortages are still a focus of research. This study use long duration of radiofrequency (RF)–magnetron sputtering to coat titanium (Ti) implant with hydroxyapatite (HA) to obtain a uniform, strongly adhered in a few micrometers in thickness. Materials and Methods Two types of substrates, discs and root form cylinders were prepared using a grade 1 commercially pure (CP) Ti rod. A RF–magnetron sputtering device was used to coat specimens with HA. Magnetron sputtering was set at 150 W for 22 hours at 100°C under continuous argon gas flow and substrate rotation at 10 rpm. Coat properties were evaluated via field emission scanning electron microscopy (FESEM), scanning electro

... Show More
View Publication Preview PDF
Scopus (17)
Crossref (15)
Scopus Crossref
Publication Date
Wed Jun 29 2022
Journal Name
Journal Of Al-rafidain University College For Sciences ( Print Issn: 1681-6870 ,online Issn: 2790-2293 )
The Use Of Genetic Algorithm In Estimating The Parameter Of Finite Mixture Of Linear Regression
...Show More Authors

The estimation of the parameters of linear regression is based on the usual Least Square method, as this method is based on the estimation of several basic assumptions. Therefore, the accuracy of estimating the parameters of the model depends on the validity of these hypotheses. The most successful technique was the robust estimation method which is minimizing maximum likelihood estimator (MM-estimator) that proved its efficiency in this purpose. However, the use of the model becomes unrealistic and one of these assumptions is the uniformity of the variance and the normal distribution of the error. These assumptions are not achievable in the case of studying a specific problem that may include complex data of more than one model. To

... Show More
View Publication
Crossref
Publication Date
Fri Jan 01 2021
Journal Name
Aip Conference Proceedings
Study of rheological and mechanical properties of bitumen blended with two alpha phases of polyamide
...Show More Authors

The effect of D phase polyamide (PA6)on the rheological properties, Young Modulus and the thermal expansion coefficient of two blends groups (bitumen-polyamide) were tested. The first group was for bitumen-PA6 blends and the second group for bitumen blended with polymer resulted from the crystallization of PA6-formic acid solution in water(PAFW).The obtained results proved that adding both types of polyamide has led to a rise in toughness and softening point temperature while the penetration Index approached -3 after adding the polyamide. So, all these changes make bitumen-polyamide blends more suitable for use in hot climate regions. The blends properties were explained according to the reaction that takes place between the polyamide and

... Show More
Preview PDF
Scopus (2)
Scopus Crossref
Publication Date
Sat Oct 28 2023
Journal Name
Baghdad Science Journal
Synthesis and investigation of structural and optical properties of CdO: Ag nanoparticles of various concentrations
...Show More Authors

This study discussed the effects of doping with silver (Ag) on the optical and structural properties of
CdO nanoparticles at different concentrations 0, 1, 2, 3, 4, 5 wt% prepared by the precipitation method. The
materials were annealed at 550˚C for 1 h. The structural, topographical, and optical properties were
diagnosed by X-ray diffraction analysis, atomic force instrument, and visible and ultraviolet spectrometers.
The results show that the average diameter of the grains depends on the percentage of added silver to the
material, as the diameter decreased from 88.8 to 59.7 nm, and it was found that the roughness increased from
5.56 to 26.5. When studying the optical properties, it was noted that th

... Show More
View Publication Preview PDF
Scopus (8)
Crossref (4)
Scopus Crossref
Publication Date
Fri Jan 01 2021
Journal Name
Aip Conference Proceedings
Study of rheological and mechanical properties of bitumen blended with two alpha phases of polyamide
...Show More Authors

View Publication
Scopus (2)
Scopus Crossref
Publication Date
Thu Oct 25 2018
Journal Name
Al–bahith Al–a'alami
Competencies of the Curriculum of Digital Media Education from the Perspective of Iraqi University Professors:
...Show More Authors

he research aims to determine the competencies that must be met in the digital media literacy curriculum, which contributes to a great extent in developing the skills of criticism and analysis of the media contents of the students. The study of the two researchers according to the methodology of the media survey. The research tools were: the questionnaire tool, which distributed on 86 . The main objectives of the research were:
1. Knowing the best strategy in teaching the digital media literacy curriculum.
2. Knowing which education fits the digital media literacy curriculum.
3. Identifying the cognitive, educational, media, technical skills, and emotional competencies required for the digital media literacy curriculum from the

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Fri Jan 01 2021
Journal Name
Materials Today: Proceedings
Evaluation of mechanical properties and cytotoxicity of maxillofacial silicone material after incorporation of zirconia nanopowder
...Show More Authors

Resilient polymeric materials such as silicone elastomers are currently used for maxillofacial prostheses construction but the strength of these materials and their clinical performance need to be optimized with the addition of reinforcing fillers. This study investigates the effect of zirconia nanopowder addition on tear strength, tensile strength, elongation at break, Shore A hardness, surface roughness and cytotoxicity of VST-50 maxillofacial silicone. Silicone base was mixed with different amounts (1%, 2% and 3%) of zirconia nanopowder using a vacuum mixer. Silicone without filler was used as control for comparison. Scanning Electron Microscopy and Atomic Force Microscopy were utilized to assess the efficiency of high-shear vacuum mixin

... Show More
View Publication
Scopus (19)
Crossref (11)
Scopus Clarivate Crossref