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 harmonic oscillator (HO) and Gaussian (GS) wave functions within the binary cluster model (BCM) have been employ to investigate the ground state neutron, proton and matter densities as well as the elastic form factors of two- neutron 6He and 16C halo nuclei. The long tail is a property that is clearly revealed in the density of the neutrons since it is found in halo orbits. The existence of a long tail in the neutron density distributions of 6He and 16C indicating that these nuclei have a neutron halo structure. Moreover, the matter rms radii and the reaction cross section (𝜎𝑅 ) of these nuclei have been calculated using the Glauber model.
In the Iraqi population, a high incidence (82.7%) of rheumatoid arthritis (RA) has been reported among the suspected patient. Many investigators studied the microbial infectious present in Iraqi patients with RA; however, to the best of our knowledge, there is no previous study detected the CMV DNA and antibodies to RA disease. Hence, the current study aimed to investigate the presence of CMV DNA and antibodies in Iraqi RA patients. A total of 58 blood samples were collected from patients with clinical signs of rheumatoid arthritis, along with 32 samples of apparently healthy individuals as a control group. These samples were tested for rheumatoid factor (RF), CMV IgM antibodies and viral DNA during the acute and
... Show MoreUsing watermarking techniques and digital signatures can better solve the problems of digital images transmitted on the Internet like forgery, tampering, altering, etc. In this paper we proposed invisible fragile watermark and MD-5 based algorithm for digital image authenticating and tampers detecting in the Discrete Wavelet Transform DWT domain. The digital image is decomposed using 2-level DWT and the middle and high frequency sub-bands are used for watermark and digital signature embedding. The authentication data are embedded in number of the coefficients of these sub-bands according to the adaptive threshold based on the watermark length and the coefficients of each DWT level. These sub-bands are used because they a
... Show More(Use of models of game theory in determining the policies to maximize profits for the Pepsi Cola and Coca-Cola in the province of Baghdad)
Due to the importance of the theory of games especially theories of oligopoly in the study of the reality of competition among companies or governments and others the researcher linked theories of oligopoly to Econometrics to include all the policies used by companies after these theories were based on price and quantity only the researcher applied these theories to data taken from Pepsi Cola and Coca-Cola In Baghdad Steps of the solution where stated for the models proposed and solutions where found to be balance points is for the two companies according to the princi
... Show MoreObjective:The current study aime to isolate Escherichia colifrom urinary tract infections(UTIs) in many Baghdad hospitals. The study concentrate on phylogenic groups and this was done based on triplex PCRmethod by primers besieged to three genetic markers, chuA, yjaA and TspE4.C2. Evaluate the relationship of phylogenic groups of E. coli isolates with the antibiotic-non sensitive patterns. Methodology:Four hundredof E.coli bacteria isolated from urine samples from five hospitals in Baghdad city include: Ghazi AL-Hariri, Ibin- Al-Beledi , AL-Iskan , AL-Nooman and AL-Yarmoke hospitals. Phylogenetic categorizatio
This study aims to study the effect of gout disease on complete blood picture and biochemical parameters and some non-enzymatic antioxidants, some tracing elements and lipid peroxidation ,in outpatients with gout disease at Al-Ramadi Teaching-Hospital ,Al-Razi Hospital and the study duration from Octo.2013-to May 2014.(50) blood samples were collected from patients with age groups (30-80 years) from both sexes (28 males,22 females),a (30) blood samples (15 males,15 females) were collected from normal individuals as a control group with age groups (27-75 years). Hematological measurement showed no significant differences in size compressed blood cells, the percentages in ( 45.15 +4.99 and 46.87+6.30) % in patient and control groups respect
... Show MoreBackground: Coronary artery spasm occurs spontaneously leading to the syndrome of variant angina. It occurs in about 15 % of patients undergoing coronary angiography.
Objectives: This study sought to estimate the rate of coronary artery spasm that occurs during coronary angiography and percutaneous coronary intervention with their risk factors in patients admitted to the Iraqi center for heart disease.
Methods: This is a cross sectional observational study, We prospectively collected the data of patients over six months period (from August 2014 till February 2015 ) who developed coronary artery spasm during cardiac catheterization (diagnostic and therapeutic).
Results: Out of 1274 patients, 106 patients developed coronary artery