This paper aims to study the effect of circular Y-shaped fin arrangement to improve the low thermal response rates of a double-tube heat exchanger containing Paraffin phase change material (PCM). ANSYS software is employed to perform the computational fluid dynamic (CFD) simulations of the heat exchanger, including fluid flow, heat transfer, and the phase change process. The optimum state of the fin configuration is derived through sensitivity analysis by evaluating the geometrical parameters of the Y-shaped fin. For the same height of the fins (10 mm), the solidification time is reduced by almost 22%, and the discharging rate is enhanced by almost 26% using Y-shaped fins compared with the straight fins. The results demonstrate that the solidification time is inversely proportional to the fin's length. The heat release rate for the case with the longest fins (stem length of 10 mm) is 39 W, almost 2.8 times higher than that with the fins' stem length of 5 mm. The case with the tributary's angle of 22.5o solidified in 55 min, faster than the other studied angles. Increasing the number of fins significantly affects the solidification time and discharging rate. By increasing the number of fins from 3 to 9, the heat transfer rate improves by 194%. The advantages of circular Y-shaped fins are well known in heat transfer applications and therefore are characterized toward higher performance in this study for the first time during the solidification process.
The nuclear size radii, density distributions and elastic electron scattering charge form factors for Fluorine isotopes (17,19,20,24,26F) were studied using the radial wave functions (WF) of harmonic-oscillator (HO) potential and free mean field described by spherical Hankel functions (SHF) for the core and the valence parts, respectively for all aforementioned isotopes. The parameters for HO potential (size parameter ) and SHF were chosen to regenerate the available experimental size radii. It was found that using spherical Hankel functions in our work improved the calculated results quantities in comparison with empirical data.
The study aimed to identify the effect of the ethical perception of a sample of managers in public organizations on responsible behavior in light of the rapid changes taking place in the external environment. To achieve this, the researcher followed the descriptive analytical approach by applying a questionnaire of two parts. The first part dealt with the ethical perception according to the scale of Johnson (2015), which consisted of (22) items. The second part dealt with measuring responsible behavior, which consisted of (20) items based on the scale of Development of Ethical Behavior (Narvaez, 2006) for a sample of (125) respondents randomly chosen. The results showed that the estimation degree of managers in public governmental o
... Show MoreThe experiment was carried out in the green house of, Biology Department of ,College of
Education , Ibn Al-Haitham , Baghdad University. For growth season 2008-2009 via planting
seeds of three genotypes of barley cultivars Baraka , Becson and Baraka x Forest ,to study the
effect of different concentrations of NaCl (o , 50 ,100 , 150 , 200 ) mM.L on some
growth parameters such as fresh and dry weight of shoot and elements plants the experiment
carried out by using completely randomized design applied with four replicates . Data were
statistically analyzed by using least significant differenceat0.05probabilitylevel.
The results showed that an increase in NaCl salt concentrations from 0 to 200mM.L
-1
leads
Abstract
Agricultural investment is one of the main requirements in most economies of the world for its importance in the development of the agricultural sector through the agricultural and technological infrastructure and agricultural research, as well as its impact on most economic, social and service activities, especially if managed and employed scientifically, which generates income and productive capacities and services and new commodities, Unemployed as agricultural investments in Iraq fell significantly after 2003 due to economic, political, social
This study concerns the isolation of oil degraded bacterial samples from oil polluted soil in Al-Dora refinery/ Baghdad – Iraq. Soil samples (15) were on mineral salt agar medium (MSM) used to screen the oil degrading bacteria by forming clear zones around the colonies. To confirm the degradation of oil by these bacteria, the isolates were inoculated in mineral salt broth, 15 isolates of Pseudomonas spp. was detected from which two isolates identified as P. aeruginosa by morphological, physical and biochemical characteristics that confirmed by using Vitick identification system. Growth was estimated in terms of whole cell by measuring optical density at 620 nm and free extract protein was estimated by protein measurement with Folin phe
... Show MoreThis study was the first of its kind on the Hindiya Dam, which is considered one of the important dams in Euphrates River. Five sites were chosen on the north of Babil Governorate in order to know the rotifers biodiversity features and the impact of the Hindiya Dam on it's during the 2019. Site2(S2) was located near the dam to reflect the rotifers diversity of this site, whereas , S1 was located at the upstream of the dam as a control site, and S3, S4 and S5 were located down the dam. Rotifers showed higher density average at Hindiya Dam site compared with sites downstream the dam which was 9164 Ind./m3, whereas density average at the site downstream the dam
... Show MoreThe present research includes the effect of different concentrations of NaCl on some biological aspects (longevity, growth and molting) of Acanthocyclops bicuspidatus (Copepoda; Cyclopoida). The results showed a decrease of longevity with the increase of salt concentrations. The lowest mean of male′s longevity was 6.8 day in the 2ppt concen. compared with the control treatment 34.2 day, The lowest mean of female′s longevity was 5.1 day in the 2ppt concen. compared with the control treatment 30.1 day. The mean growth for males was lower than the mean growth of females. In males the lowest m
... Show MoreAbstract
The aim of the research is to develop specific skills of 21 century, one schedule, renewable: (sex, years of experience, academic degree) from the viewpoint of the research sample. The descriptive tool was used to collect information for research purposes. It was applied to a sample of (339) male and female teachers in Al-Ardhah governorate schools to teach Jazan. The application was carried out in the second semester of the year 1442 AH. The research concluded with a set of results, the most important of which are: the approval of the sample members to a large extent on the expressions of the role of school leaders in the practice of developing male and female teachers in acquiring these three skills fr
... Show MoreABSTRACT
Threw this research to the following:
1 - Know the impact of strategy Puglia in the collection of the rules of the Arabic language
students at the Institute of preparation parameters .
2 - Know the impact of the retention strategy in Puglia collection rules Arabic language
students at the Institute of preparation parameters .
To verify the status Mmermaa Find researcher Elsafreeten following two hypotheses :
1 - There is no statistically significant difference between the average score for the collection
of the fourth grade students at the Institute for the preparation of material parameters who
were studying grammar strategy Puglia and average grades collectible fourth grade
students at the Institu