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 present research aims at identifying the educational problems and psychological problems of distinguished students at the intermediate level. The research sample consists of (246) students who are randomly selected from four distinguished schools (2) in the Karkh\1 and (2) in the Rusafa\2.

The researcher has constructed two scales for measuring the educational and psychological problems. She ensures the psychometric characteristics of the two scales. Alph-Cronbach and test-retest methodsare used to ensure reliability. Some statistical treatments are used to find out the aims of research. These treatments include the one-sample T-test, two independent samples T-test, and the Pearson correlation coefficient. The results show th

Arabian Political Regimes: Problems of Policies and Rule; An Introduction to Interpreting (The Arabian Spring) The Arab Region witnessed, since 2011, critical changes overthrew a group of Arab regimes in some of its countries, and the reaction of these changes are still going on up to now. These changes were given lots of justifications and interpretations. The current study tries to concentrate on the most important problems which were due to what was known as (The Arab Spring). The study proposes that the crisis which the countries of the area are exposed to is not spontaneous in many of its aspects. It is totally a crisis of rule and policies. Because it is a reflection of the nature of authority in the Arabian regimes on the one hand

        The linguistic researcher reads a systematic crisis, idiomatic problems within the linguistic term coming to the Arab culture. Where most of them return back to problems of receiving these sciences which are represented by phenomena like the multiplicity linguistic term, disturbance translated idiomatic concept and its duality.

Aims of the research :

1-Initializing new textbooks to form linguistic project and Arabic linguistic theory.

2-Determination adjusted knowledge, concepts of Arabian heritage linguistics subject

3-Observation  the causes of disturbance crisis of linguistic term and its relation to

This research presents a model for surveying networks configuration which is designed and called a Computerized Integrated System for Triangulation Network Modeling (CISTNM). It focuses on the strength of figure as a concept then on estimating the relative error (RE) for the computed side (base line) triangulation element. The CISTNM can compute the maximum elevations of the highest
obstacles of the line of sight, the observational signal tower height, the contribution of each triangulation station with their intervisibility test and analysis. The model is characterized by the flexibility to select either a single figure or a combined figures network option. Each option includes three other implicit options such as: triangles, quadri