The performance of a vapor compression refrigeration system (VCRS)-based residential air conditioner operating in a high-ambient temperature (HAT) country was investigated using six zero-ODP (ozone depletion potential) refrigerants as replacements to R22. The non-flammable alternative refrigerants considered in the present research were R134a, R404A, R407C, R410A, R448A, and R507A. Using the basic conservation laws, the VCRS was modeled during steady-state operation and solved using engineering equation solver (EES) software. Coefficient of performance (COP), pressures and temperatures at compressor suction and discharge, Global Warming Potential (GWP), critical pressure and temperature, compressor pressure ratio, volumetric cooling capacity (VCC) specific cooling capacity (SCC), and refrigeration effect were utilized as assessment criteria for the alternative refrigerants considered. From these refrigerants, the highest values of suction pressure, discharge temperature, and condenser pressure were attained by R410A. In addition, the discharge temperatures for all refrigerants, except R134a, were all higher than their corresponding critical values, causing a quicker drop in the VCRS’s performance. As an alternative refrigerant, R407C showed the highest SCC of 141.0 kJ/kg followed directly by 139.2 and 138.0 kJ/kg for R410A and R448A, respectively. A reverse trend was found for VCC with respective values of 4722 and 3775 kJ/m3 for R410A and R448A. Lower volume flow rates and smaller-sized compressors are expected for higher VCC refrigerants. The same trend was found for the compressor’s specific work input and condenser’s specific heat transfer with values of (51.14, 46.82, and 45.38 kJ/kg) and (190.3, 187.8, and 183.4 kJ/kg) for R410A, R407C, and R448A, respectively. For applications in HAT countries, larger condenser’s specific heat transfer makes the refrigerant more applicable. Conversely, with respect to COP, refrigerant R134a with a value of 3.075 was the superior alternative followed by R448A and R407C with respective COPs of 3.042 and 3.011. Based on the overall assessment in terms of environmental obligation, COP, compressor input power, refrigerant flow rate required, and all the evaluations made in this research, refrigerant R448A was recommended as the most appropriate substitute to R22 which can effectively be used in residential air conditioners in a HAT country.
There are risks and benefits with all medicines and estrogen replacement is no exception. In fact, estrogen replacement is one of the most controversial topics in Endocrinology. Anastatica hierochuntica L. is a popular treatment for the management of female reproductive disorders. The present research highlights the effect of aqueous extract of plant against conjugated estrogen(Premarin) in rabbits. Femal oryciolagus cuniculus rabbits were divided into four groups: the 1 st group, rabbits were orally administered (using a feeding solution )with daily dose(5 mL distilled water)for two months, the 2nd group, the rabbits were treated with conjugated estrogen (50 µg/kg b.w, body weight )for one month. The 3rd group, the rabbits were treated w
... Show MoreAnastatica Hierochuntica L. Used As an Alternative of Conjugated Estrogen (Premarin) in Rabbit Females
There are risks and benefits with all medicines and estrogen replacement is no exception. In fact, estrogen replacement is one of the most controversial topics in Endocrinology. Anastatica hierochuntica L. is a popular treatment for the management of female reproductive disorders. The present research highlights the effect of aqueous extract of plant against conjugated estrogen(Premarin) in rabbits. Femal oryciolagus cuniculus rabbits were divided into four groups: the 1 st group, rabbits were orally administered (using a feeding solution )with daily dose(5 mL distilled water)for two months, the 2nd group, the rabbits were treated with conjugated estrogen (50 µg/kg b.w, body weight )for one month. The 3rd group, the rabbits were treated wi
... Show MoreAbstract The concept of quantum transition is based on the completion of a succession of time dependent (TD) perturbation theories in Quantum mechanics (QM). The kinetics of "quantum" transition, which are dictated by the coupled motions of a lightweight electrons and very massive nuclei, are inherent by nature in chemical and molecular physics, and the sequence of TD perturbation theory become unique. The first way involved adding an additional assumption into molecule quantum theory in the shape of the Franck-Condon rule, which use the isothermal approach. The author developed the second strategy, which involved injecting chaos to dampen the unique dynamically of the bonding movement of electrons and nuclei in the intermediary state of
... Show MoreThe city of Samawah is one of the most important cities which emerged in the poverty area within the poverty map produced by the Ministry of Planning, despite being an important provincial centre. Although it has great development potentials, it was neglected for more than 50 years,. This dereliction has caused a series of negative accumulations at the urban levels (environmental, social and economic). Therefore, the basic idea of this research is to detect part of these challenges that are preventing growth and development of the city. The methodology of the research is to extrapolate the reality with the analysis of the results, data and environmental impact assessment of the projec
A numerical investigation was performed on triangular solar air collectors by integrating unique layouts of triangular and alternating triangular copper metal foams with graded and non-graded pore densities. A three-dimensional CFD model was established to solve the governing equations of coupled systems for porous and non-porous domains. The two-energy-equations model was implemented to simulate heat transfer in porous media. The mathematical model was validated with numerical and experimental tests, with maximum mean absolute percentage error of 5% and 7%, respectively. To compromise heat transfer improvement with pressure losses, a partial metal foam insertion was adopted, covering 10% to 25% of the air duct volume. The findings indicate
... Show MoreBackground/Aim: Capsicum annuum Grossum Senise, a widely cultivated sweet pepper in Iraq contains a diverse array of bioactive compounds such as polyphenols, carotenoids and capsinoids, known for their beneficial effects on health. The study aimed to employ advanced analytical techniques to elucidate the compound's chemical properties and concentration within this specific Capsicum cultivar, contributing to the growing body of knowledge regarding plant-derived sterols with potential nutraceutical application. Methods: This study focused on the extraction, isolation, purification and quantitative analysis of b-sitosterol from Iraqi Capsicum annuum Grossum. Advanced chromatographic and spectroscopic techniques were employed to ensure
... Show MoreThe formal investigation of the interior spaces of the residential bedrooms for children with autism is one of the basic tasks that should be known by the interior designer. Achieving an atmosphere compatible with his health condition, which contributes to generating a sense of spatial intimacy through the design dimension provided by the interior designer and his tireless endeavor to meet the needs of the child in an internal environment that achieves the functional dimension and spiritual approaches that enhance the child’s sense of spatial belonging and contribute to improving his mood and this positively reflects on his behavior and social integration. The current research has reached the most important design criteria that must be
... Show MoreAround fifty isolates of Salmonella enterica serovar Typhi were isolated from blood specimens of patients referring to several hospitals in Kirkuk province, Iraq. The results revealed that all isolates developed resistance to trimethoprim-sulfamethoxazole and chloramphenicol. However, neither sul2 nor tem genes were detected. Moreover, only ten isolates were positive for catP. Our data suggested participation of other genes or mechanisms allow these multidrug isolates to resist the antibiotics in question.