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 Colour is one of important aspect of human activity, especially in General arts and press, and also is one of the essential elements to achieve and build the idea of design technology in the appropriate places, according to the space of designs work.
In a view of the colour and its relationship with the Semiotics, we can find that the objectives goals at the point of visual formats that’s «oral or written”. In last years, the intellectual concerns of Semiotics through eye contact methods, that’s meaning contact methods for get messages of sense of sight.
The semiotics term Can be defined into: (the sequential feature or network system has relations according agreed language rules, in a particular environment, also is a g
Our life is a test and the eternal life in the afterlife. So we must work well in our life even win paradise, must always remember the death and there is a life after this death and we will be responsible for everything we've done in our life. God did not create us vain but for reward, punishment, for this we must have to well prepare for this great day and we have to think about what to do in order to win the paradise.
Keywords: paradise, surat al-rahman, preparation.
Digital literacy is crucial in the modern workforce, where technology plays an integral role in daily operations. This abstract explores the significance of digital literacy in enhancing productivity, efficiency, and competitiveness in the workplace. Digital literacy encompasses the ability to use and navigate digital tools and platforms effectively, including software, applications, and online communication tools. In today's digital age, employers increasingly value candidates with strong digital skills, as they are better equipped to adapt to rapidly evolving technologies. This abstract highlights the importance of digital literacy in empowering employees to perform tasks more efficiently, collaborate seamlessly, and innovate effecti
... Show MoreThe research aims to identify the effect of teaching-learning design based on the constructivism theory on the life skills of middle stage students. The sample consisted of (60) students from one of the middle schools in Baghdad's governorate. The experimental group and control group consisted of 30 students for each group, the research tool was the life skills scale composed of (78) items. The scale proved its validity and reliability, which was found to be (0.85). The results showed a statistically significant difference in life skills between the two groups of research in favor of the experimental group, which studied the educational design according to models of constructivism theory compared to the usual method of teaching.
2 The benefit of the leave of our time is the leakage and inclusion in the series of narrators of modern.
3 The leave is therefore permissible to narrate the hadeeth or other sciences from a sheik or sheiks, and not
the talk.
4 It is not necessary that the grantee of the leave has studied the student who is the holder of the leave.
5 - in which a great meaning is the sense of the recipient seeking blessing through the link
With attribution to our master Muhammad peace be upon him.
The high bounce activity according to the fosbery way is regarded as of the difficult sports concerning its way of training and perfection due to hard technique of its performance on one hand and because it depends on the player’s ability to overcome body weight resistance against the gravity. In addition to the strong ability to control the body posture when leaving the land and flying over the barrier. This activity needs to high plosion power at the moment of bouncing and this plosion depends on the period of bouncing, so the two researchers aimed to use a mechanical bouncing platform and an electronic one through several training by one foot and both feet in different directions and positions in order to reduce the time of bouncing an
... Show MoreObjectives: To assess the relation between breast cancer & blood groups, identify the importance of women
age group and the relation of age with breast cancer.
Methodology: The study was performed on (115) women who were diagnosed with breast cancer in different
stages of disease and different ages. Blood samples were taken from them to demonstrate their blood groups and
(20) fresh tumor tissue samples were obtained; the tumor tissue used as a source of lectin for hemagglutinate
with erythrocyte of different blood groups. The study conducted at Baghdad Teaching Hospital and Radiation &
Nuclear Medicine Hospital from January, 2007 through June 2007.
Results: The study shows that the highest percentage of women
The research aims to show the dimensions of organizational trust represented by (administrative policies opportunities for innovation and self innovation and self- realization,availability of information,prevailing organizational values) and its reiationship to achieving the strategic position of banks represented by formation of expectations,buiiding networks,learning operations As the research was applied in each of the banks (middle east)Iraqi investment,Al-Ahly Iraqi, Business Bay, Al- Mansour investment bank),the qusestionnaire was adopted as a tool to collect data and information from the sample number (138)who are in the site (department director, division ,M.division director ,division officer, unit officer)the statistica
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