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Energy and Exergy Analyses of Heat Pump Cycle with Refrigerant Injection Technology
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The effect of refrigerant injection techniques on the performance of heat pump system based on exergy analysis was studied theoretically. Three refrigerant injection techniques were used; the first was achieved by injected vapour in volume ratios from 1 to 7% in the accumulator. The second was injection liquid refrigerant in the discharge line with the aid of Liquid Pressure Amplification (LPA) pump, with volume ratios from 1 to 10%. The third was a hybrid injection with volume ratios of injected vapour and liquid varied from 1 to 3% and 1 to 10%; respectively. The following improvements in cycle performance were observed. For vapour injection technique, the best ratio of injection was 5%, the exergy destruction reduced by 21% and exergy efficiency enhanced by 14.6%. For liquid injection technique the best ratio of injection was 6%, the reduction in exergy destruction was 34% while the exergy efficiency increased by about 21.4%. The hybrid injection technique increased the exergy efficiency by 23% when the volume ratio of vapour and liquid injections are 3% each. The effect of condensing pressure on the cycle performance was studied also. The optimum exergy efficiency of the cycle was 54.55% achieved when the condensing pressure was 15 bars.

                                              

 

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Publication Date
Thu Jan 21 2010
Journal Name
Iraqi Journal Of Veterinary Medicine
Production and Partial Purification of Heat-Stable Enterotoxin (A) Produced by Enterotoxigenic Escherichia coli
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A total of (25) stool samples were collected from children and adults (2- 4) years old suffering from diarrhea to isolate E. coli strains that produce heat-stable enterotoxin a (STa), and after performing microscopic examination, cultural characterization and biochemical identification only (11) isolates showed positive E. coli. STa activity was estimated by using suckling mouse assay (SMA) and from these (11) isolates only (5) showed STa activity and the one with the highest STa activity was selected for large scale production of STa, which was followed by partial purification using ion-exchange chromatography (normal phase) using DEAE sephadex A-50 column. After purification and determination of protein concentration by using the standard

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Publication Date
Thu May 18 2023
Journal Name
Journal Of Engineering
Evaluation of Convective Heat Transfer and Natural Circulation in an Evacuated Tube Solar Collector
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The evacuated tube solar collector ETC is studied intensively and extensively by experimental and
theoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climate
from April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collector
consists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relation
between convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect of
tube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.e
closed and open flow) to evaluate the heat loss coefficient

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Publication Date
Tue Mar 31 2015
Journal Name
Al-khwarizmi Engineering Journal
Experimental Study of the Thermal Diffusivity and Heat Capacity Concerning Some Duplex Stainless Steel
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Abstract

In the present work, thermal diffusivity and heat capacity measurements have been investigated in temperature range between RT and 1473 K for different duplex stainless steel supplied by Outokumpu Stainless AB, Sweden. The purpose of this study is to get a reliable thermophysical data of these alloys and to study the effect of microstructure on the thermal diffusivity and heat capacity value. Results show the ferrite content in the duplex stainless steel increased with temperature at equilibrium state. On the other hand, ferrite content increased with increasing Cr/Ni ratio and there is no significant effect of ferrite content on the thermal diffusivity value at room temperature. Furthermore, the heat capacity of all sam

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Publication Date
Sun Feb 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
The possibility of applying CAPP technology to improve the quality of the product
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     The research deals with A very important two subjects, computer aided process planning (CAPP) and Quality of product with its dimintions which identified by the producer organization, the goal of the research is to Highlight and know the role of the CAPP technology to improve quality of the product of (rotor) in the engines factory in the general company for electrical industries, The research depends case study style by the direct visits of researcher to the work location to apply the operational paths generated by specialized computer program designed by researcher, and research divides into four axes, the first regard to the general structure of the research, the second to the theoretical review, the t

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Publication Date
Thu May 21 2026
Journal Name
Iraqi Journal Of Science
UNSTEADY PRESSURE DROP AND HEAT TRANSFER OFMAGNETOHYDRODYNAMIC ANNULAR TWO-PHASE INRECTANGULAR CHANNEL
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An annular two-phase, steady and unsteady, flow model in which a conductingfluid flow under the action of magnetic field is concavely. Two models arepresented, in the model one; the magnetic field is perpendicular to the long side ofthe channel, while in the model two is perpendicular to the short side. Also, westudy, to some extent the single-phase liquid flow.It is found that the motion and heat transfer equations are controlled by differentdimensionless parameters namely, Reynolds, Hartmann, Prandtl, and Poiseuilleparameters. The Laplace transform technique is used to solve each of the motion andheat transfer equations. The effects of each of dimensionless parameters upon thevelocity and heat transfer is analyzed.A comprehensive study fo

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Publication Date
Sun Jan 01 2023
Journal Name
Computers, Materials & Continua
An Efficient Method for Heat Recovery Process and燭emperature燨ptimization
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Publication Date
Wed Mar 20 2019
Journal Name
Al-khwarizmi Engineering Journal
Enhancement of Heat Exchanger Performance by Using Dimpled Tube
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The enhancement of heat exchanger performance was investigated using dimpled tubes tested at different Reynolds numbers, in the present work four types of dimpled tubes with a specified configuration manufactured, tested and then compared performance with the smooth tube and other passive techniques performance. Two dimpled arrangements along the tube were investigated, these are inline and staggered at constant pitch ratio X/d=4, the test results showed that Nusselts number (heat transfer) of the staggered array is higher than the inline array by 13%.  The effect of different depths of the dimple (14.5 mm and 18.5 mm) has been also investigated; a tube with large dimple diameter enhanced the Nusselts number by about 25% for the ran

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Publication Date
Wed Jan 11 2023
Journal Name
J. Of Kirkuk Univ. For Agri. Sci.
THE HARMFUL CONSEQUENCES OF HEAT STRESS ON CHICKENS INDUSTRY
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This article dealt with identifying the importance of heat stress in poultry flocks and the damages resulting from the production of eggs and meat and the spread of pathogens, in addition to that ways to mitigate the harmful effects of heat stress, including physiological, nutritional, engineering and genetics, in order to ensure preservation of the product and reduce damages

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Publication Date
Fri Dec 30 2022
Journal Name
Al-mustansiriyah Journal Of Science
Study of Photons Emission Rate of Quark-Antiquark at Higher Energy
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In this paper, the dynamic of quark and anti-quark interaction has been used to study the production of photons in the annihilation process based on the theory of chromodynamic. The rate of the photon is to be calculated for charm and anti-strange interaction c→γg system with critical temperature 113 and 130 MeV and photon energy GeV/c. Here the critical temperature, strength coupling and photons energy are assumed to be affected dramatically on the rate of photons emission of state interaction c, which can form gluon possible structures and photon emission state. The decreased photons emission yields with increased strength couple of quarks reaction due to increase critical temperature from 113 MeV to 130 MeV were predicted. We

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Theoretical Investigations of Vibrational – Rotational Energy of some Hydrogen Halide Molecules
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A theoretical study by using computer model is presented to study the energy characteristics of the vibrational – rotational levels as a function of the vibrational and rotational quantum number, respectively. The calculations were based on the basis of a multilevel model taking into account the non-equilibrium population of the rotational levels. The computational investigation has been performed to examine the vibrational-rotational characteristics of some hydrogen halides chemical laser molecules. This program takes into account the various molecules of chemical lasers such as, Hydrogen Fluoride (HF), Deuterium Fluoride (DF), Hydrogen Chloride (HCl), and Deuterium Chloride (DCl). The practical difficulties associated with this

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