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.
Consequence of thermal and concentration convection on peristaltic pumping of hyperbolic tangent nanofluid in a non‐uniform channel and induced magnetic field is discussed in this article. The brief mathematical modeling, along with induced magnetic field, of hyperbolic tangent nanofluid is given. The governing equations are reduced to dimensionless form by using appropriate transformations. Exact solutions are calculated for temperature, nanoparticle volume fraction, and concentration. Numerical technique is manipulated to solve the highly non‐linear differential equations. The roll of different variables is graphically analyzed in terms of concentration, temperature, volume fraction of nanoparticles, axial induced magnetic fie
... Show MoreSeveral adipokines are produced and secreted from adipose tissue, such as retinol binding protein-4, which triggers metabolic syndromes and insulin resistance. Retinol binding protein-4 transfers vitamin A or retinol in the blood. Higher levels of retinol binding protein-4 are interrelated with progress of metabolic disease, comprising obesity, metabolic syndrome, and type 2 diabetes mellitus. The present study investigates the role of retinol-binding protein-4 levels in type 2 diabetic Iraqi patients with metabolic syndrome. Sixty type 2 diabetic patients aged 40–53 years were examined. Of these 30 patients has metabolic syndrome and 30 without metabolic syndrome. The patients sampled were from the National Diabetes Center/ Mustansiriyah
... Show MoreIn this study the Entrance Surface Dose (ESD) received by pediatrics patients undergoing chest, abdomen and skull X-ray examinations was estimated. The study was conducted in two hospitals in Najaf city where three radiographic systems were considered. The study participants were classified into four age groups 0-1 , 1-5 , 5-10 and 10-15 years. Calculations were performed using exposure factors, kVp, mAs and focal-skin distance, together with patient data age. The ESD was calculated for the involved patients who underwent an Antero-posterior (AP) chest, abdomen and skull X-ray examination. The resulted data were analyzed and compared with international dose references. For all studied radiographic examinations and all X-ray mac
... Show MoreDam operation and management have become more complex recently because of the need for considering hydraulic structure sustainability and environmental protect on. An Earthfill dam that includes a powerhouse system is considered as a significant multipurpose hydraulic structure. Understanding the effects of running hydropower plant turbines on the dam body is one of the major safety concerns for earthfill dams. In this research, dynamic analysis of earthfill dam, integrated with a hydropower plant system containing six vertical Kaplan turbines (i.e., Haditha dam), is investigated. In the first stage of the study, ANSYS-CFX was used to represent one vertical Kaplan turbine unit by designing a three-dimensional (3-D) finite element (F
... Show MoreBackground: Multidrug-resistant (MDR) enterococci have become a major problem in recent times and have been reported increasingly around the world. Lytic phages infect bacteria leading to rapid host death with limited risk of phage transduction, underlining the increasing interest in potential phage therapy in the future. Objective (s): The aim of this study is to use phage therapy as alternative approach for treatment of Enterococcus faecalis infections that recorded as MDR in Iraq to tackle this problem. Materials and Methods: Thirty E. faecalis isolates were collected from patients with different infectious diseases such as urinary tract infection (UTI), diabetic foot, septicemia, and wound infections. The isolation of specific l
... Show MoreIn recent years, the positioning applications of Internet-of-Things (IoT) based systems have grown increasingly popular, and are found to be useful in tracking the daily activities of children, the elderly and vehicle tracking. It can be argued that the data obtained from GPS based systems may contain error, hence taking these factors into account, the proposed method for this study is based on the application of IoT-based positioning and the replacement of using IoT instead of GPS. This cannot, however, be a reason for not using the GPS, and in order to enhance the reliability, a parallel combination of the modern system and traditional methods simultaneously can be applied. Although GPS signals can only be accessed in open spaces, GP
... Show MoreThe study aimed to examine the sensitivity to stress and its relation to positive mood among educational supervisors. The researcher used the descriptive approach as more an appropriate method for the current study. The sample is composed of (200) educational supervisor. To collect study data, two scales have been used: one scale to measure the sensitivity to stress and the other to measure the positive mood. The results indicated that a high level of sensitivity to stress with low level of positive mood among educational supervisors, sensitivity to stress showed significant differences among the sample regarding to major. There is no correlation between sensitivity to stress and positive mood, and finally, there are no significant diffe
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