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.
The aim of the research is to prepare practical volleyball lessons by using the four pillars strategy for middle school students, and to identify the effect of the four pillars strategy in performing the transmission and volleyball skills in the second intermediate students, to assume that the two researchers assume that there are no statistically significant differences between the results of my skill performance tests Sending and preparing tribal and remote volleyball for the experimental and controlled groups, and there are no statistically significant differences between the results of the performance of the transmission and preparation skills of the volleyball between the two experimental and control groups, and the research co
... Show MoreThe research aims to evaluate Islamic electronic libraries and their service for downloading research and illustrated books, explaining their origins, features and types. The research was limited to the libraries available on the Internet that provide the service for downloading research and illustrated books. The researcher relied on the survey approach to identify the libraries and a sample of them (20 libraries) was selected. For the purpose of evaluating it according to five criteria related to the preparation and publication of Islamic electronic libraries (the responsible party, the goals and objectives, the year, the services it provides, the sections and subject specializations of its contents) and five criteria related to the servi
... Show MoreBackground: Pemphigus vulgaris (PV) is an autoimmune vesiculobullous mucocutaneous disease with life-threatening consequences. Rituximab (RTX) has recently emerged as an effective treatment for PV. Objectives: This study aims to determine changes in neutrophil and platelet counts for PV patients treated with RTX or corticosteroids combined with Imuran (azathioprine). Materials and Methods: The present cross-sectional study was conducted in the Department of Dermatology at Baghdad Teaching Hospital, Baghdad, Iraq. Thirty PV patients received two types of treatment: 15 patients were administered RTX and 15 patients took corticosteroids with Imuran (azathioprine). Neutrophil and platelet counts were detected at the hospital laboratory. Results
... Show MoreThis paper designed a fault tolerance for soft real time distributed system (FTRTDS). This system is designed to be independently on specific mechanisms and facilities of the underlying real time distributed system. It is designed to be distributed on all the computers in the distributed system and controlled by a central unit.
Besides gathering information about a target program spontaneously, it provides information about the target operating system and the target hardware in order to diagnose the fault before occurring, so it can handle the situation before it comes on. And it provides a distributed system with the reactive capability of reconfiguring and reinitializing after the occurrence of a failure.
In this paper the variable structure control theory is utilized to derive a discontinuous controller to the magnetic levitation system. The magnetic levitation system model is considered uncertain, which subjected to the uncertainty in system parameters, also it is open-loop unstable and strongly nonlinear. The proposed variable structure control to magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, which induced due to the discontinuity in control law, is attenuated by using a non-smooth approximate. With this approximation the resulted controller is a continuous variable structure controller with a determined steady state error according to the selected control
... Show MoreSystem is one of the concepts that fused stages of human thought his contemplations , and the evolution of his ideas and know the universe and existence , was formed several systems and numerous multi- humanitarian field , for example : the political system , the economic system , the system of philosophical , scientific system ... etc. .The current research around trying to find the identity of the system aesthetic in general and theater in particular , the detection of compositions and how Cklath within shifts functional and conceptual , which confirms the importance of Altgria creative as characterized by the following heading towards experimentation and update ongoing , and in particular what we find in the discourse of postmodernism
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