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 accomplish

The world is confronted with the twin crisis of fossil fuel depletion and environmental degradation caused by fossil fuel usage. Biodiesel produced from renewable feedstocks such as Jatropha seed oil or animal fats by transesterification offers a solution. Although biodiesel has been produced from various vegetable oils such as Jatropha seed oil, the reaction kinetics studies are very few in literature, hence the need for this study. Jatropha curcas seed oil was extracted and analyzed to determine its free fatty acid and fatty acid composition. The oil was transesterified with methanol at a molar ratio of methanol to oil 8:1, using 1% sodium hydroxide catalyst, at different temperature

This research aims to analyze the intellectual and civilizational regression that afflicted Iraqi and Arab society due to political and religious tyranny and internal conflicts, which was reflected in the deterioration of human rights values and the absence of equality and justice in dealing with the other religiously, which affected the reluctance of members of religious groups to interact with their national societies and then migrate to Outside, which contributed to a double loss, in terms of the loss of these societies by productive and effective national competencies, and in terms of distorting the image of Islam. The research stressed that the first treatments of this phenomenon are the consolidation of the values of citize

This study concluded detection of Toxoplasma gondii in milk, immunologically by using Elisa and nested PCR)nPCR (based on B1 gene, also to investigate the effect of toxoplasmosis, parity, breed and flock on some milk composition in the Iraqi local and Shami goats in the middle of Iraq. A total of 80 milk samples of the lactating goats were collected. Results of this study showed the prevalence of Toxoplasmosis was 21.25% and 28.75% by Elisa and nPCR respectively without significant differences. The sensitivity of Elisa was a low (30.43%) whereas the specificity was a high (82.45%). The degree of agreement estimated by Kappa coefficient revealed a slight agreement (0.14) between two methods. The results indicated that goats infected

Item Difficulty and Item Discrimination Coefficient for School and College Ability Tests (SCAT) Advanced Form in Classical Test Theory (CTT) and Item Response Theory (IRT) and the Correlation among Them Mohammad moqasqas Haifa T. Albokai Assistant Professor of Measurement and Evaluation Associate Professor of Measurement and Evaluation College of Education, Taibah University The aim of this study was to study the item difficulty and item discrimination of the SCAT (advance form) with CTT, and IRT, and to study the correlation among them. To do this, the researchers used the data of their previous study, which conducted in (2011). It consisted of (3943) subject. Then, they used two-statistical programs (TAP, Bilog-MG-3) to obtain the item

       The dielectric properties of polyvinyl chloride (PVC)-MnCl2 composite were studied by using the impedance technique. The measurements were carried out as a function of frequency in the range from 10 Hz to 13 MHz and temperature range from 27oC to 55oC. Using a composite of 20 wt. % MnCl2 by weight, it was found that the dielectric constants and the dielectric loss of the prepared films increase with the increasing temperature at law frequency and the enhancement of the ionic conduction which is confirmed by the increase the of AC. conductivity and the decrease of the activation energy of the conduction mechanism at high applied frequency. The observed relaxation and polarization effects of composite a

The city is often discussed in barren, eviscerated terms and in technical jargon by urban professionals as if it were a lifeless, detached being. In fact, it is a sensory, emotional, lived experience. How often do strategic urban plans start with the words ‘beauty’, ‘love’, ‘happiness’ or ‘excitement’, as opposed to ‘bypass’, ‘spatial outcome’ or ‘planning framework, So the research problem was formed by the weakness of the sensory perception of cities and the weakness of the sense of different spaces, which in turn leads to weakness of belonging, identity and clarity, Therefor we focus here on the sensory perception. The hypothesis Recognize Senses as helpful tool in increasing people's understanding of differe

The research includes an introduction on Unmarried as one of the most dangerous phenomena's in Arab society in general and Iraqi society in specific especially after last decades wars that ruined the country and enlarged the number of unmarried women. First chapter dealt with the research problem that was increasing day after another while the percentage of unmarried women became 85% due to embargo and wars made by ex-regime that led to kill many Iraqis and decreasing marriage chances.

The research aims to recognize the reasons behind that and tries to find solutions by using quest ways and tools to get rid of old habits that represent obstacle marriage. The research dealt with unmarried in Arab countries where National Instituti

The emergence of the Internet and its transformation in the early nineties of the last century led to a means of mass communication that brought about significant structural changes in the media map.

Over the course of historical development, the public did not engage the media in its behavior in the implementation and dissemination of an idea, generalization or theory put forward by media experts or practitioners through these means to do it. Blogs represent the most important service provided by the Internet in recent years which has gained special importance in the media field. Where the word “Blogs” has several names: (alternative media), (blogging press), (popular press) and other names.

The medi