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.
In this work, the effect of ceramic coating on performance, exhaust gas temperature and gases emissions of diesel engine operated on diesel fuel and biodiesel blends was investigated. A conventional four stroke, direct injected, single cylinder, diesel engine was tested at constant speed and at different load conditions using diesel fuel and biodiesel blends. The inlet and exhaust valves, the head of piston and cylinder head of the engine were coated by ceramic materials. Ceramic layers were made of (210-240) μm of Al2O3 and (30-60) μm of 4NiCr5Al as a bond coat for inlet and exhaust valves and (350-400) μm of YSZ and (50-100) μm of 4NiCr5Al as a bond coat for head of piston and (280-320) μm of Sic and (40-80) μm of 4NiCr5Al as a b
... Show MoreOne of the main significant purposes of learning the English language is the need to have an effective communication allowing for exchange and transmitting information. As a basic form of human communication that allows people to connect, communicate, and share experiences with one another is writing skill. Through practicing trainable abilities like speaking, and writing, adaptation skills are required to overcome issues that develop in unfamiliar environments. Learners must be cognitively flexible to reconstruct and adjust to these situations' demands. This study aims at looking into the level of cognitive flexibility and writing abilities of Iraqi EFL university students. It also seeks to determine how these two variables are related. It
... Show MoreThis field experiment, was conducted to investigate a comparison of two methods for harvesting potatoes: mechanical and handy when using moldboard and chisel plow for primary tillage and three different distances for planting tubers in the rows 15, 25, and 35 cm in silt clay loam soil south of Baghdad. The factorial experiment followed a randomized complete block design with three replications using L.S.D. 5 % and 1 %. Mechanical harvest recorded the best valid potato tubers at 88.78 %, marketable yield of 31.74 ton. ha-1, efficiency lifted 95.68 %, tubers damage index 28.41, speeding up the harvesting process and reducing time and effort. Handy harvest gave the least damage to potato tubers, 6.02 %, and unlifted potato tubers, 4.32 %. Howe
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Abstract
The aim of the research is to clarify the requirements of the qualification of the external auditor in Iraq and the extent of their impact on the quality of the professional performance of the audit process. The research was based on analyzing the results of the questionnaire prepared for the impact of qualifications on the quality of professional performance. The researcher has reached a number of conclusions, the most important of which is that a highly qualified and unethical auditor has a greater negative impact on the quality of professional performance than those with low qualifications. The most important recommendations of the research were the need to pay
... Show MoreThis paper details the process of designing, analysing, manufacturing, and testing an integrated solid-state hydrogen storage system. Analysis is performed to optimise flow distribution and pressure drop through the channels, and experimental investigations compare the effects of profile shape on the overall power output from the fuel cell. The storing of hydrogen is given much attention in the selection of a storage medium, and the effect of a cooling system to reduce the recharging time of the hydrogen storage vessel. The PTFE seal performed excellently, holding pressure over 60 bar, despite requiring changing each time the cell is opened. The assembly of the vessel was simple and straightforward, and there was no indication of pressure
... Show MoreAddress the intellectual controversy nature of the gap of knowledge and the strategic performance gap. The researcher start off from this intellectual controversy to seek to test the nature of the relationship and impact between them across a sample of (61) academics in the colleges of business and economics at the universities in Baghdad ,as the more specialized in the fields of knowledge and the strategic performance, The researcher is attain to the existence of relationship and impact of knowledge gap in strategic performance gap, the research included four axes first went to the methodology and second to theoretical frame and the third to view and analyze the results and test hypotheses while the fourth was devoted to the con
... Show MoreThe body of the actor and its expressive significance is an essential topic in studying acting . it is not only confined to the study of soul and body from philosophical aesthetic perspective , but also to study the conception and mechanism of such a dichotomy followed by theatre directors and theorists , who are highly concerned with the creativity of actors . The researchers believe that such a study would be of benefit for actors as well as others working in theatre .
The study falls into two sections . the first deals with the phi
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