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Prediction of Heat Transfer Coefficient and Pressure Drop in Wire Heat Exchanger Working with R-134a and R-600a
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An experimental and theoretical works were carried out to model the wire condenser in the domestic refrigerator by calculating the heat transfer coefficient and pressure drop and finding the optimum performance. The two methods were used for calculation, zone method, and an integral method. The work was conducted by using two wire condensers with equal length but different in tube diameters, two refrigerants, R-134a and R-600a, and two different compressors matching the refrigerant type. In the experimental work, the optimum charge was found for the refrigerator according to ASHRAE recommendation. Then, the tests were done at 32˚C ambient temperature in a closed room with dimension (2m*2m*3m). The results showed that the average heat transfer coefficient for the R-600a was higher than the R-134a, so the length of the wire tube was longer with R-134a than R-600a. The pressure drop for the smaller tube diameter was higher than the other tube. The second law thermodynamic efficiency was higher for R-600a, which reached 41%.  The entropy generation minimization analysis showed that the R-600a refrigerant type and smaller tube diameter are approached the optimum point.

 

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Publication Date
Sun May 08 2011
Journal Name
Journal Of Planner And Development
The use of GIS in the analysis of existing condition of spatial distribution of wire communications network in the city of Baghdad
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The increasing efficiency of the telecommunications network in the city contributes to the increase in spatial interaction between activities (to influence and mutual influence) This study is based on the idea that the upgrading of telephone services provided to citizens are done exclusively through the growth and development of all levels of the service using advanced technologies to know the problems and appropriate solutions in short time and less cost. Thus, crystallized the objectives of the study which was built for the importance of GIS in the planning of services in general, and infrastructure services, in particular, including telephone services, which is represent a point of contact between individuals on the one hand a

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Publication Date
Mon Mar 25 2019
Journal Name
Al-academy
Working of the Secondary Event Structure in Embodying the Film Unity: ماهر مجيد ابراهيم - شروق مالك
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The topic of the working of the secondary event structure in the embodiment of the film unity is related to the ability to produce a film of controlled events that strengthen each other. The researchers divided the subject topic into an introduction and two sections, as follows: The first section is the event and the action in drama construction wherein the relationship of the dramatic act with the events in general and the secondary event in particular were studied as it has a relationship in a synergistic building of the film unity.

The second section was the patterns of the secondary event in the film wherein the researchers dealt with the patterns, types and functions

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Publication Date
Mon Dec 18 2017
Journal Name
Al-khwarizmi Engineering Journal
Optimization and Prediction of Process Parameters in SPIF that Affecting on Surface Quality Using Simulated Annealing Algorithm
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Incremental sheet metal forming is a modern technique of sheet metal forming in which a uniform sheet is locally deformed during the progressive action of a forming tool. The tool movement is governed by a CNC milling machine. The tool locally deforms by this way the sheet with pure deformation stretching. In SPIF process, the research is concentrate on the development of predict models for estimate the product quality. Using simulated annealing algorithm (SAA), Surface quality in SPIF has been modeled. In the development of this predictive model, spindle speed, feed rate and step depth have been considered as model parameters. Maximum peak height (Rz) and Arithmetic mean surface roughness (Ra) are used as response parameter to assess th

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Publication Date
Tue Jan 01 2013
Journal Name
Iraqi Journal Of Physics
The dependence of resonant tunneling transmission coefficient on well width and barriers number of GaN/Al0.3Ga0.7N nanostructured system
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A numerical computation for determination transmission coefficient and resonant tunneling energies of multibarriers heterostructure has been investigated. Also, we have considered GaN/Al0.3Ga0.7N superlattice system to estimate the probability of resonance at specific energy values, which are less than the potential barrier height. The transmission coefficient is determined by using the transfer matrix method and accordingly the resonant energies are obtained from the T(E) relation. The effects of both well width and number of barriers (N) are observed and discussed. The numbers of resonant tunneling peaks are generally increasing and they become sharper with the increasing of N. The resonant tunneling levels are shifted inside the well by

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Publication Date
Sun Feb 24 2019
Journal Name
Iraqi Journal Of Physics
The dependence of resonant tunneling transmission coefficient on well width and barriers number of GaN/Al0.3Ga0.7N nanostructured system
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A numerical computation for determination transmission coefficient and resonant tunneling energies of multibarriers heterostructure has been investigated. Also, we have considered GaN/Al0.3Ga0.7N superlattice system to estimate the probability of resonance at specific energy values, which are less than the potential barrier height. The transmission coefficient is determined by using the transfer matrix method and accordingly the resonant energies are obtained from the T(E) relation. The effects of both well width and number of barriers (N) are observed and discussed. The numbers of resonant tunneling peaks are generally increasing and they become sharper with the increasing of N. The resonant tunneling levels are sh

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Publication Date
Thu Dec 13 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Contemporary Risk Factors of High Blood Pressure for Youth Group (18-24) Years for Students of Technical Institute in Baquba and University of Diyala
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Objective: This study aimed to investigate the relationship between high blood pressure and
different variables, such as (weight, smoking, amount of salt and water taken daily, and number
of hours of natural sleep per person) for young people.
Methodology: The study was conducted on students at the student community of the Technical
Institute in Baquba and the University of Diyala during the period from September 2015
until June 2016. The patients ranged in age from 18-24 years. All data were collected through
a questionnaire that included the main reasons and periodic follow-up of the disease.
Results: The total number of samples was 450.The results showed that 33% of all samples
have high blood pressure. The rel

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Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
Effect of Argon and oxygen pressure on Zn magnetron plasma produced by RF power supply
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In this work, the plasma parameters (electron temperature and
electron density) were determined by optical emission spectroscopy
(OES) produced by the RF magnetron Zn plasma produced by
oxygen and argon at different working pressure. The spectrum was
recorded by spectrometer supplied with CCD camera, computer and
NIST standard of neutral and ionic lines of Zn, argon and oxygen.
The effects of pressure on plasma parameters were studied and a
comparison between the two gasses was made.

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Publication Date
Sun Dec 30 2012
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Hydrodynamic Pressure Gradient Correlation of Some Iraqi Oil Wells
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Empirical equation has been presented to predict the optimum hydrodynamic
pressure gradient with optimum mud flow rate (one equation) of five Iraqi oil wells
to obtain the optimum carrying capacity of the drilling fluid ( optimum transport
cuttings from the hole to the surface through the annulus).
This equation is a function of mud flow rate, mud density and penetration
rate without using any charts or graphs.
The correlation coefficient accuracy is more than 0.9999.

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
Comparison Between the Methods Estimate Nonparametric and Semiparametric Transfer Function Model in Time Series Using Simulation
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Publication Date
Thu Aug 22 2019
Journal Name
Al-khwarizmi Engineering Journal
Optimizing the Parameters of Hot-wire CNC Machine to Enhance the Cutting of Plastic Foam
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     Hot-wire cutting is one of the important, non-traditional thermomechanical way to cut polymer, usually expanded foam and extruded foam, in low volume manufacturing. The study and analysis of Hot-Wire cutting parameters play an important role to enhance the quality and accuracy of the process and products. The effects on the surface have been investigated by using experimental tests designed according to the Taguchi orthogonal array (OA). In this study, four parameters with five levels for each parameter have been used: [temperature of wire (A) (100, 120, 130, 150, 160) °C], [diameter of wire (B) (0.3,0.4,0.5,0.7,0.8) mm], [velocity of cutting (C) (200, 300,400,500,600) mm/min], [and density of foam (D) (0.01,0.0

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