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The Experimental Assessment of R134a and Its Lower GWP Alternative R1234yf in an Automobile Air Conditioning System
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Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.

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Publication Date
Wed Dec 30 2015
Journal Name
College Of Islamic Sciences
The absurdity of Orientalist thought and its deviation in interpretation Quranic text View and critique
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The absurdity of Orientalist thought and its deviation in interpretation
Quranic text
View and critique

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Publication Date
Thu Oct 03 2013
Journal Name
Heat Transfer-asian Research
CFD Simulation of Heat Transfer Augmentation in a Circular Tube Fitted with Alternative Axis Twisted Tape in Laminar Flow under a Constant Heat Flux
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Publication Date
Sat Sep 30 2023
Journal Name
Journal Of The College Of Education For Women
The Problem of Paradox and its Manifestations: A Study in the Titles of Najm Wali's Novels
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The irony pushes us to inquire about what is in the text of contradiction, irony, suspense, and other acts of paradox, as well as a departure from what is logical, or familiar, that attracts the attention of the addressee, and this is what drives us to introspect the text and interrogate it in order to get to know the intended product of the text or its real or metaphorical intent. On the other hand, the irony is more in the literary text than in the scientific texts. Therefore, critics add the word literature to it in their definition.

 As it is represented by the paradox, we will seek to study the paradox of the title and the problematic that it may pose as the beginning of the text, and i

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Publication Date
Tue Jul 12 2022
Journal Name
Proceedings Of Seventh International Congress On Information And Communication Technology
Identification of Key Criteria of Selecting the Delivery System and Type of Contract in Construction Projects
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Publication Date
Mon Jun 19 2023
Journal Name
Journal Of Engineering
Active Carbon from Date Stones for Phenol Oxidation in Trickle Bed Reactor, Experimental and Kinetic Study
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The catalytic wet air oxidation (CWAO) of phenol has been studied in a trickle bed reactor

using  active  carbon  prepared  from  date  stones  as  catalyst  by  ferric  and  zinc  chloride activation (FAC and ZAC). The activated carbons were characterized by measuring their surface area and adsorption capacity besides conventional properties, and then checked for CWAO using a trickle bed reactor operating at different conditions (i.e. pH, gas flow rate, LHSV, temperature and oxygen partial pressure). The results showed that the active carbon (FAC and ZAC), without any active metal supported, gives the highest phenol conversion. The reaction network proposed account

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Publication Date
Tue Mar 15 2022
Journal Name
Al-academy
the indication of the scene as a symbolic system in the Iraqi theatrical
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The theatrical view reflects various connotations and intellectual and aesthetic implications, as the view includes a symbolic geometric, architectural and archetypal connotation suggestive of reality and nature, as theatrical art is the woman that reflects reality, specifically the significance of the theatrical view that reveals to us the philosophical, aesthetic and cognitive dimensions of theatrical trends, so the research came with the methodological framework, which It included the research problem (what is the significance of the scene as a symbolic system in the Iraqi theatrical performance), the importance of the research and the need for it, the research objective, the limits of the research and the most important terms.
A

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Publication Date
Thu Mar 31 2016
Journal Name
Al-khwarizmi Engineering Journal
Experimental Study of the Performance of Compound Parabolic Concentrating Solar Collector
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The design, construction and investigation of experimental study of two compound parabolic concentrators (CPCs) with tubular absorber have been presented. The performance of CPCs have been evaluated by using outdoor experimental measurements including the instantaneous thermal efficiency. The two CPCs are tested instantly by holding them on a common structure. Many tests are conducted in the present work by truncating one of them in three different levels. For each truncation the acceptance half angle (θc) was changed. Geometrically, the acceptance half angle for standard CPC is (26o). For the truncation levels for the other CPC 1, 2 and 3 the acceptance half angle were 20o, 26o and 5

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Publication Date
Thu Feb 01 2018
Journal Name
Journal Of Engineering
Experimental Investigation of the Electro Co-deposition of (Zinc-Nickel) Alloy
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An experimental investigation has been carried out for zinc-nickel (Zn-Ni) electro-deposition using the constant applied current technique. Weight difference approach method was used to determine the cathode current efficiency and deposit thickness. Also, the influence effect of current density on the deposition process, solderability, and porosity of the plating layer in microelectronic applications were examined. The bath temperature effect on nickel composition and the form of the contract was studied using Scanning Electron Microscope (SEM). Moreover, elemental nature of the deposition was analyzed by Energy Dispersive X-Ray (EDX).     

It has been found that the best bath temperature

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Publication Date
Fri Dec 30 2022
Journal Name
College Of Islamic Sciences
Verses of cheerfulness and fluency of the face in the Holy Qur’an: An Objective Study
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Most of us are tired of the circumstances that surround us because of their deficiency, deprivation, and sullenness, even though troubles and pains are the soil in which the seeds of strong personality  sprout.             

   The content of the research is summed up in the fact that there is no need to frown, so let our face be free, and our word good and tolerant, so that we can be the most loving people of those who give them, and the Messenger of God (may God’s prayers and peace be upon him and his family) was known to be the heaviest  concerns  of people, but he was most smiling of people, by smiling, we buy lives, so we should get used to it, because that gives us hope and finds the world in our hands, an

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Publication Date
Wed Oct 11 2023
Journal Name
Journal Of Educational And Psychological Researches
Content Assessment of the Sciences Textbooks of Grades (1-4) in the Light of International Standards in Mathematics and Science TIMSS 2019 (Content Dimension)
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The current research aims to determine the requirements of Trends of International Mathematics and Science Study (TIMSS 2019) and to find out the extent to which the content of science textbooks for grades (1-4) in the Sultanate of Oman includes the requirements of (TIMSS 2019). Only the content dimension has been taken into account when conducting the content analysis. The study population includes all science books from the first to the fourth grade for the academic year 2021-2022. The study identified and organized the requirements in the study tool, which is a list of requirements of (TIMSS 2019). The results showed a general deficiency in all grades (1-4) in the content dimension including many main topics, subtopics, and objectives

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