A mathematical model has been formulated to predict the influence of high outdoor air temperature on the performance of small scale air - conditioning system using R22 and alternative refrigerants R290, R407C, R410A. All refrigerants were investigated in the cooling mode operation. The mathematical model results have been validated with experimental data extracted from split type air conditioner of 2 TR capacity. This entailed the construction of an experimental test rig which consists of four main parts. They are, the refrigeration system, psychrometric test facility, measuring instrumentation, and auxiliary systems. The conditioned air was maintained at 25 0C dry bulb and 19 0C wet bulb for all tests. The outdoor ambient air temperature was varied from 35 0C to 55 0C in 5 0C increments. The study showed that R290 is the better replacement for R22 when the air conditioning system works under high ambient temperature. It has better performance as a drop in refrigerant. R407C has the closest performance to R22, followed by R410A.
Abstract:Leukemia is a cancer of early blood forming cells. Most of them are cancers of white blood cells , however some leukemias start in other blood cell types.Electrolytes have modulatory effects on several biological mechanisms in the body namely as stabilizers,element of structures, essential element for hormonal function and also co-factors for a number of enzymes.In this study serum electrolytes levels were measured in patients with acute leukemia (AL) disorders before and after chemotherapy(anthracycline, doxorubicin, cytarabine ,prednisone, vincristine and doxorubicin) during one month and compared with that of control group. Blood samples were obtained from (43) patients (28 males and 15 females) aged (15-55)years;juset before an
... Show MoreAlgeria is one of the states that are important to the Ottoman state, because of its geographic location is important to the Mediterranean Sea, as well as the economic resources of the nature of its soil geography and climate,diverse, making it the focus of attention of the Ottomans, along with the van, which has increased the interest of the Ottomans in Algeriais the fall Andalusat the hands of the Spaniardsin1492, and force the Muslims to get out of them, and did not Only Europeans do it, butrushed to the prosecution of Muslims tothe coast of North Africa and seizing control of manyofits ports and cities, prompting the Ottoman state to go forth and back to the barn Muslims,Especially after hehad appealed to the Arabs of the Ottoman sta
... Show MoreIn this study, the electro-hydraulic servo system for speed control of fixed displacement hydraulic motor using proportional valve and (PID) controller is investigated theoretically ,experimentally and simulation . The theoretical part includes the derivation of the nonlinear mathematical model equation of (valve – motor ) combination system and the derivation of the transfer function for the complete hydraulic system , the stability test of the system during the operation through the transfer function using MATLAB package
V7.1 have been done. An experimental part includes design and built hydraulic test rig and simple PID controller .The best PID gains have been calculated experimentally and simulation, speed control performance te
The food web is a crucial conceptual tool for understanding the dynamics of energy transfer in an ecosystem, as well as the feeding relationships among species within a community. It also reveals species interactions and community structure. As a result, an ecological food web system with two predators competing for prey while experiencing fear was developed and studied. The properties of the solution of the system were determined, and all potential equilibrium points were identified. The dynamic behavior in their immediate surroundings was examined both locally and globally. The system’s persistence demands were calculated, and all conceivable forms of local bifurcations were investigated. With the aid of MATLAB, a numerical simu
... Show MoreThe research seeks to examine the ability of fifth preparatory students in solving a mathematical problem in relation to system thinking. To this end, the researcher chose (140) fifth preparatory students from four-different secondary schools in Kirkuk city for the academic year (2016-2017). Two tests were adopted to collect study data: a test of (5) items about skills in solving math problem designed by (Al-raihan, 2006); and a test of system thinking skills designed by the researcher himself consisted of (14) items. It was divided into four skills (analyzing the main system to subsystems, eliminating all inner gaps of system, identifying the inner connection of system, and reorganizing the system). The findings indicated a good ability
... Show MoreThe result showed that hot water and ethanol extracts of Nigella sativa contain alkaloids ,saponins, flavonoids,tannins,glycosides,terpins and steroids. Albino mice were administered orally with 0.1 of the extract at dose of 100 mg/kg, body weight the results showed high level of white blood cell ,total and differential count of WBC,phagocytosis index, mitotic index, Arthus and delayed type hypersensitivity. The result, also showed high level of hemoglobin (Hb) and the packed cell volume (PCV) the alcoholic extract has been found more efficient than hot water extract on mice.
The research aims at identifying the organizational performance of the kindergarten teachers and defines the educational environment of kindergarten children. To achieve the objectives of the research, the researcher adopted the organizational performance scale for (Saadi, 2016), which was applied to kindergarten teachers. The scale consists of (43) paragraphs, and has good reliability and validity, as the coefficient of reliability (84.0) in a retest method, and (87.0) using the formula Alpha Kronbach. Additionally, the researcher adopted the educational environment scale for (Radam, 2015); the scale consists of (66) paragraphs, and it enjoys a good reliability and validity, as the coefficient of reliability (89.0) method of reliability
... Show MoreFour new complexes of Pd(II), Pt(II) and Pt(IV) with DMSO solution of the ligand 8-[(4-nitrophenyl)azo]guanine (L) have been synthesized. Reaction of the ligand with Pd(II) at different pH gave two new complexes, at pH=8, a complex of the formula [Pd(L)2]Cl2.DMSO (1) was formed, while at pH=4.5,the complex[Pd(L)3]Cl2.DMSO (2) was obtained. Meanwhile, the reaction of the ligand with Pt(II) and Pt(IV) revealed new complexes with the formulas[Pt(L)2]Cl2.DMSO (3)and [Pt(L)3]Cl4.DMSO (4) at pH 7.5 and 6 respectively.
All the preparations were performed after fixing the optimum pH and concentration. The effect of time on the stability of these complexes was checked. The stoichiometry of the complexes was determined by the mole ratio and Job
A total of 247 specimens of the Mallard were collected from Baghdad city and kut City and 154 specimens the collection was started from October1999