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Exergy Analysis of a Domestic Refrigerator
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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.

 

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Publication Date
Fri Jan 11 2019
Journal Name
Iraqi Journal Of Physics
Study of starch, sugar blending effect on the biodegradability of (PVA) for packaging applications
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PVA, Starch/PVA, and Starch/PVA/sugar samples of different
concentrations (10, 20, 30 and 40 % wt/wt) were prepared by casting
method. DSC analysis was carried; the results showed only one glass
transition temperature (Tg) for the samples involved, which suggest
that starch/PVA and starch/PVA/sugar blends are miscible. The
miscibility is attributed to the hydrogen bonds between PVA and
starch. This is in a good agreement with (FTIR) results. Tg and Tm
decrease with starch and sugar content compared with that for
(PVA). Systematic decrease in ultimate strength, due to starch and
sugar ratio increase, is attributed to (PVA), which has more hydroxyl
groups that made its ultimate strength higher than that for

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Study of Some Physical and Chemical Properties of Staphylolysin Enzyme purified from Pseudomonas aeruginosa
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Some of the characters of the Staphylolysin A and D enzymes purified from Pseudomonas aeruginosa P16 and P5 respectively were studied, the molecular weights of Staphylolysin A and D were 20.417 kilo dalton and 23.988 kilo Dalton respectively by SDS- polyacryl amide gel electrophoresis. The optimum pH for staphylolysin A activity was found to be 8 which gives higher activity reaches 150 unit/ml, and for enzyme stability was 7.5-8.5 in which the enzyme nearly retained its full activity, while it was 9.5 for staphylolysin D that gives higher activity of 16 unit/ml,and 8.5-9.5 for enzyme stability in which the enzyme nearly retained its full activity, Maximum activity of two enzymes was obtained at 40C in which the specific activity for st

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Publication Date
Sun Mar 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
The effectiveness of the organization in the philosophy of the most prominent theoreticianAdministrative thought
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This paper discuses the mindset contribution of the organization Science in organizational effectiveness (OE), and the most valuable thoughts they introduced in this subject, starting from the pre- classical era, through classical era to present time. This paper has identified the main contribution in OE. The concept of OE didn’t arise until what had been introduced by Chester Barnard, although Max Weber mentioned this concept in his bureaucratic theory, but he didn’t explain it as Barnard does. After that no clear focus was pointed to this subject until Peter Drucker did so, which considered as the main participant in OE after Barnard. After that many researchers be interested in OE and they start studying this subject like

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Publication Date
Fri Apr 01 2016
Journal Name
Journal Of Engineering
Experimental Behavior of Steel-Concrete-Steel Sandwich Beams with Truss Configuration of Shear Connectors
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This paper presents experimentally a new configuration of shear connector for Steel-Concrete-Steel (SCS) sandwich beams that is derived from truss configuration. It consists of vertical and inclined shear connectors welded together and to cover steel plates infilled with concrete. Nine simply supported SCS beams were tested until the failure under a concentrated central load (three- point bending). The beams were similar in length (1100mm), width (100mm), and the top plate thickness (4mm). The test parameters were; beam thickness (150, 200, 250, and 300mm), the bottom plate thickness (4, and 6mm), the diameter of the shear connectors (10, 12, and 16mm), and the connector spacing (100, 200, and 250mm). The test results sh

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Publication Date
Thu Dec 31 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Analyzing the reality of the Iraqi market for securities in light of financial globalization
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The Iraqi market for securities in light of financial globalization faces real challenges at the local and international levels, which were reflected in their shadows on the overall economic reality, which imposed the necessity of making fundamental changes in terms of form and content, and from here stems the research problem in the ability of the Iraqi stock market to adapt to the transformations Financial imposed by financial globalization in light of the weakness of the economic structure and its position in the global economy. The research starts from the hypothesis that the Iraqi market for securities in light of financial globalization has an important and significant role in the economic field, through its role in stimula

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Publication Date
Mon Apr 29 2024
Journal Name
Euphrates Journal Of Agricultural Science
Effect foliar of some organic fertilizers on growth and yield of four potato cultivars
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Publication Date
Sat Jan 01 2011
Journal Name
Journal Of Engineering
PHYSICAL MODEL OF KEROSENE PLUME MIGRATION IN AN UNSATURATED ZONE OF THE SANDY SOIL
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Physical model tests were simulated non-aqueous phase liquid (NAPL) spill in two-dimensional
domain above the water table. Four laboratory experiments were carried out in the sand-filled
tank. The evolution of the plume was observed through the transparent side of this tank and the
contaminant front was traced at appropriate intervals. The materials used in these experiments
were Al-Najaf sand as a porous medium and kerosene as contaminant.
The results of the experiments showed that after kerosene spreading comes to a halt (ceased) in
the homogeneous sand, the bulk of this contaminant is contained within a pancake-shaped lens
situated on top of the capillary fringe.

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Publication Date
Sat Jun 30 2012
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Effect of Annealing on the Crystallization of Poly Vinyl Chloride for Drug Delivery System
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Poly vinyl alcohol has been studied for its ability to form crystallites by using annealing method. Semicrystalline films of poly vinyl alcohol (PVA) were prepared by casting 11.5 wt. % and 13 wt. % PVA aqueous solution onto glass slides at annealing temperature range 90 -120°C and duration time 15- 60 minute. This allowed the macromolecules to form crystallites, small regions of folded and compacted chains separated by amorphous regions where single PVA chain may pass through several of these crystallites. Degree of crystallinity of PVA films (hydrogels) was determined by method of density; on the other hand the swelling behavior was conducted by the determination of water uptake, wet degree of crystallinity, gel fraction and solubilit

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Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
The use of management principles to Fayol in the implementation of competitive strategies Porter
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This paper aims to review the intellectual to the most important thought leaders administrative and strategic They both (Henry Fayol and Michelle Porter), who forward a lot of ideas that have helped countries in the advancement and progress their economies , has been drawing literature theoretical common border in Contributions ( Fayol ) philosophical and between applications ( Porter ), which reversed strategies of the three ( the leadership of the cost, differentiation, and focus ), so browse search how to apply and use the principles of Fayol in the implementation of strategies competitiveness of Porter, and stems from a problem ( ( to what extent a reflection of the principles ( Fayol) fourteen strategies (Porter ) competitiv

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Publication Date
Wed Oct 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
The role of paid the offices of the Inspectors General on mutation fraud Crimes
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       Fraud crimes, which is a form of crimes against the funds in public office, is one of the crimes of traditional and cutting-edge in the same time, but it took a distinct character from other traditional crimes because of what is based upon, behavioral fundamentals and foundations and expressive image of personal qualities, concentrated in the mental work, the inventive sophistication, and skillful abilities of the perpetrators of these crimes, in addition to what is owned by crooks today a behavioral ability represented in underestimating laws and instructions. Fraud is considered one of the organized crime methods It is the most important method of its methods, all crimes practiced by the cro

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