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.
The research is based on an important subject according to the researchers' estimations. It is the disclosure of the nature of the relationship between Watching to cultural programs in satellite channels and the book's vision of the intellectual, and the pursuit of purchasing and acquiring it It is a scientific addition to the scientific research media because it deals in the field of new about the nature of the relationship between satellite programs and writers, and it provides a scientific development on the importance of satellite channels in the promotion of the book and sales of intellectual elite. The study examined the audience of the recipients of literature for cultural programs, the nature of the public, characteristic
... Show MoreDigital commercial advertising depends on artistic formations to achieve attraction and arousal of attention, which is one of the most important communication factors that the designer seeks to achieve and is considered a key key to recognizing the beauty of the topic and its functional value. Reframe formal vocabulary.
The research included the introduction and includes the research problem and the need for it, which focused on the following question: What is the aesthetic role of artistic formation in the design of commercial advertising?
The aim of the research was: To reveal the aesthetic role of artistic formation in commercial advertising.
It also included the importance of research and research boundaries, as well as def
The concept of social graphic design is one of the most critical areas that highlight the designer's knowledge of social responsibility by employing design skills in community awareness. This study focused on defining social graphic design, the meaning, practices, and strategies for designing awareness posters. This study reviewed two examples of awareness posters that reflect the Saudi designer's practices. The results summarized that social graphic design is a concept not taught directly but gained from permanent practice in designing awareness posters that interact with community issues. The designer's understanding of his social events and their sensing in the visual form of a poster reflects the designer's social awareness. Social g
... Show MoreIn the present work the performance of semifluidized bed adsorber was evaluated for removal of phenolic compound from wastewater using commercial activated carbon as adsorbent. P-chlorophenol (4-Chlorophenol) and o-cresol (2-methylphenol) was selected as a phenolic compound for that purpose. The phenols percent removal, in term of breakthrough curves were studied as affected by hydrodynamics limitations which include minimum and maximum semifluidization velocities and packed bed formation in the column by varying various parameters such as inlet liquid superficial velocity (from Uminsf to 8Uminsf m/s), and retaining grid (sometimes referred to as adsorbent loading) to initial static bed height ratio (from 3-4.5). In
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Research Summary
The doctrine of belief in the Last Day is one of the pillars of faith, and the doctrine of resurrection and reckoning are part of this day.
Belief in the Last Day puts a person in constant control over himself, as this control creates in this person happiness and a decent life, and he renounces the world and turns away from all vices and adorns all virtues.
On the other hand, we find that the person who does not believe in this day does not stand before his eyes anything that prevents him from doing injustices and corruption in the land. The doctrine of belief in the Last Day alone is
... Show MoreOrganism is considered one of the intellectual products that search for compatibility and harmony with the natural environment. Man has adopted on since the ancient times in choosing his residence through imitating nature such as animal burrows, hives, bird nests and others of the natural manifestations being spontaneous inspirations. With the development of the age, these concepts turned into an analysis that examines the philosophy that deals with the shapes and functions of various elements in the nature as a source of inspiration, and discusses the call for contemplation and achieving benefits physically and spiritually in line with the nature of the organic thought that seeks to keep up with modern technologies that are characterize
... Show MoreThe design fabrics of the most important episodes that are at the core process rhetorical communication, until they became these episodes ample room for research and investigation, and the issue of non-familiar formality is nothing but the result of those relationships Constructivism, which is the result of an effort builders coherent activate the shape and attributes of phenotypic, therefore it will cause him a lot of questions about his and founded the organization in order to activate the speech communication between the product(cloth)and the receiver .On this basis, the research problem identified on imposing the question follows:1. Does the non-familiar formal role in enriching communication discourse of women's fabric designs?2. Ar
... Show MoreThe chemical additives used to enhance the properties of drilling mud cause damage to humans and the environment. Therefore, it is necessary to search for alternative additives to add them to the drilling mud. Thus, this study investigates the effects of pomegranate peel and grape seed powders as natural waste when added to un-weighted water-based mud. The test includes measurements of the rheological properties and filtration, as well as the alkanity and density of the drilling mud. The results showed a decrease in PH values with an increase in the concentrations of pomegranate peel or grapeseed, and a decrease in mud density with an increase in powders of pomegranate peel and grape seed concentrations that resulted f
... Show MoreResearching performance audits according to the dimensions of financial sustainability in light of the scarcity of resources and economic and social transformations in the business environment is of utmost importance in the non-profit non-governmental organizations in achieving the goals and correct the path and address deviations, and help them in improving the outputs of processes and associated procedures and capacity The research was based on the hypothesis that the existence of a performance audit program in accordance with the dimensions of financial sustainability leads to the measurement of the commitment of the Olympic Committee. National Iraqi indicators of financial sustainability of the dimension of revenue in order to improv
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