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

A gracious invitation was extended to us on 9/11/2002 AD, by the University of Tikrit / the Preparatory Committee, for a symposium (Sheikh Daoud Al-Tikriti, and his Scientific Effects), to participate in it.
The symposium was scheduled to be held on the 25th and 26th of March 2003 AD, but God Almighty decreed that our country be occupied, so the Preparatory Committee set another date for the symposium on 10/21/2003 AD.
It was not possible for the symposium to be held until 25-26/4/2004 AD, and many researchers attended, who were assigned to investigate some manuscripts of Sheikh Dawood (may God have mercy on him) or to write about his personal and scientific biography.
And God (Glory be to Him) did not enable us to attend, becau

The research tagged with the controversy of aesthetic interpretation between the sculptures and their titles in contemporary Iraqi sculpture, “Exhibition of Experiments in Contemporary Iraqi Sculpture as a Model”, and it is one of the new research that contributes to strengthening the critical path in the Iraqi fine movement, as the first chapter dealt with the research problem stemming from the question: What is the impact of the aesthetic hermeneutic controversy between the title and the title in contemporary Iraqi sculpture?, and do the titles of the sculptural works help to understand or enhance their contents?, The research objective included: To identify the controversy of the aesthetic interpretation of sculptures and their ti

This research is an attempt to achieve the following objectives: 1. identifying the nature of the non-verbal communication skills practiced by educational counselors in individual guidance. 2. Identifying the significant differences between non-verbal communication skills exercised by educational counselors from their point of view in regard to their gender (male-female). The researcher used a questionnaire as a tool prepared based on exploratory questions of educational counselors and literature. It has consisted of (26) items over four domains applied to a sample of (50) educational counselors (male and female) who have been chosen randomly from schools located in Baghdad Education Directorate Rusafa / 2. It was treated statistically u

The research started from the basic objective of tracking the reality of organizational excellence in educational organizations on the basis of practical application. The research in its methodology was based on the examination of organizational excellence in the way of evaluating institutional performance. Tikrit University was selected as a case study to study the reality of application to the dimensions of organizational excellence in it, The results of the analysis for ten periods during the year and month. For the accuracy of the test and its averages, it was preferable to use the T test to determine the significance of the results compared to the basic criteria.

The research found that there is an o

In this paper, the theoretical cross section in pre-equilibrium nuclear reaction has been studied for the reaction  at energy 22.4 MeV. Ericson’s formula of partial level density PLD and their corrections (William’s correction and spin correction) have been substituted  in the theoretical cross section and compared with the experimental data for  nucleus. It has been found that the theoretical cross section with one-component PLD from Ericson’s formula when  doesn’t agree with the experimental value and when . There is little agreement only at the high value of energy range with  the experimental cross section. The theoretical cross section that depends on the one-component William's formula and on-component corrected to spi

The constructivist learning model is one of the models of constructivist theory in learning, as it generally emphasizes the active role of the learner during learning, in addition to that the intellectual and actual participation in the various activities to help students gain the skills of analyzing artistic works. The current research aims to know the effectiveness of the constructivist learning model in the acquisition of the skills of the Institute of Fine Arts for the skills of (technical work analysis). To achieve the goal, the researcher formulated the following hypothesis: There are no statistically significant differences between the average scores of the experimental group students in the skill test for analyzing artworks befor

The present study investigated the use of pretreated fish bone (PTFB) as a new surface, natural waste and low-cost adsorbent for the adsorption of Methyl green (MG, as model toxic basic dye) from aqueous solutions. The functional groups and surface morphology of the untreated fish bone (FB) and pretreated fish bone were characterized using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS),respectively. The effect of operating parameters including contact time, pH, adsorbent dose, temperature, and inorganic salt was evaluated. Langmuir, Freundlich and Temkin adsorption isotherm models were studied and the results showed that the adsorption of basic dye followed Freundlich iso

In this research local wheat peel was used as an adsorbent surface for removal of Azure B (AB) dye from the aqueous solution. The adsorption process was performed at different experimental parameters, equilibrium time, temperature, ionic strength and solution pH. The isotherms of adsorption are of H-type as compared with Giles curves and the adsorption data were coincide with Freundlich equation. The adsorption kinetic data were analyzed using pseudo- first and second order kinetic models. The effect of temperature was studied and the amount of dye adsorbed was found to increase with the increasing of temperature from 25 to 50 oC. The values of thermodynamic functions like enthalpy and entropy have been estimated. The quantity of adso