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.
Theoretical and experimental investigations of the transient heat transfer parameters of constant heat flux source subjected to water flowing in the downward direction in closed channel are conducted. The power increase transient is ensured by step change increase in the heat source power. The theoretical investigation involved a mathematical modeling for axially symmetric, simultaneously developing laminar water flow in a vertical annulus. The mathematical model is based on one dimensional downward flow. The boundary conditions of the studied case are based on adiabatic outer wall, while the inner wall is subjected to a constant heat flux. The heat & mass balance equation derived for specified element of bulk water within the annulu
... Show MoreBackground: Tuberculosis infection represents a global health problem and a great risk to Health Care Workers. Identifying individuals, particularly Health Care Workers with latent tuberculosis infection will support tuberculosis control through chemoprophylaxis and prevent cross-infection. The aim of this study was to assess the prevalence and some risk factors for latent tuberculosis infection among Health Care Workers in three tuberculosis health institutions in Baghdad.
Methods: A cross-sectional study was conducted in 2013 in Baghdad- Iraq on Health Care Workers working in the Specialized Respiratory & Chest Diseases Center (Tuberculosis institute), Ibn Zuhur Hospital for Chest Diseases and
The estimation of the stressÙ€ strength reliability of Invers Kumaraswamy distribution will be introduced in this paper based on the maximum likelihood, moment and shrinkage methods. The mean squared error has been used to compare among proposed estimators. Also a Monte Carlo simulation study is conducted to investigate the performance of the proposed methods in this paper.
Simple, sensitive and accurate two methods were described for the determination of terazosin. The spectrophotometric method (A) is based on measuring the spectral absorption of the ion-pair complex formed between terazosin with eosin Y in the acetate buffer medium pH 3 at 545 nm. Method (B) is based on the quantitative quenching effect of terazosin on the native fluorescence of Eosin Y at the pH 3. The quenching of the fluorescence of Eosin Y was measured at 556 nm after excitation at 345 nm. The two methods obeyed Beer’s law over the concentration ranges of 0.1-8 and 0.05-7 µg/mL for method A and B respectively. Both methods succeeded in the determination of terazosin in its tablets
Background: Diabetic foot problems are one of the most important complications of diabetes mellitus
which causing a worldwide high cost morbidity which could be due to poor self-practices.
Objectives: To assess the preventive food care practices among diabetic patients and to find out any
significant association of these practices with selected socio-demographical and diabetic related
characteristics.
Patients and Methods: A descriptive cross-sectional study was conducted in Baquba city from the
period of 20th Septembers, 2016 up to 20th March, 2017, by selecting a sample of (120) patients by
using a structured questionnaire, the questionnaire composed of three parts, the first part contains
information related to
Background: Oxidative stress is a deleterious process that can be an important mediator of damage to cell structures and consequently various disease states. Exposure to free radicals from a variety of sources has led organisms to produce a series of defense mechanisms. The antioxidant ceruloplasmin is a copper-containing ferroxidase that can oxidize ferrous iron (Fe2+) to its nontoxic ferric (Fe3+) form. Ferrous iron (Fe2+) is extremely damaging because of its ability to generate toxic free radicals. Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease of unknown etiology. Previous studies reported that reactive oxygen species may be involved in the pathogenesis of lichen planus. The aim of this study was to estimate the
... Show MoreThe expression of MUC5AC has been associated with the loss of the differentiation, TNM system, and nodal metastasis, in many cancers including gastric carcinoma (GC).Objective: To evaluate whether the MUC5AC could be used as a predictor in patients with GC and to assess the correlation between the expression of MUC5AC& the clinicpathological parameters as age, sex, histopathological subtypes, grade and stage of the tumor. This is a retrospective study conducted on 60 randomly selected patients (30 normal vs 30 GC), at the Pathology Department of the Gastroenterology and Hepatology Teaching Hospital&some private laboratories. They were collected and diagnosed during the period 2014-2018. Histological sections were stained wi
... Show MoreThe aim of the study is to assess the risk factors which lead to myocardial infarction and relation to some variables. The filed study was carried out from the 1st of April to the end of Sept. 2005. The Sample of the study consisted of (100) patients in lbn-Albeetar and Baghdad Teaching Hospital. The result of the study indicated the following; 45% of patients with age group (41-50) were more exposed to the disease and there is no significant difference was seen in the level of education, Martial status, weight and height. The result shows that there are significant difference in risk factors like hypertension, cholesterol level in blood and diabetes. When analyzed by T.test at level of P < 0.01 and there are significant difference in smoki
... Show MoreBreast cancer (BC) is the most commonly diagnosed cancer in women. The metabolism of iron is closely regulated by hepcidin which exerts its action by interacting with a ferroportin.
The aim of the present study was to assess the alterations in the levels of some serum biomarkers that have a role in iron homeostasis (hepcidin and ferroportin) in addition to hematological parameters (hemoglobin, leukocyte and platelets count) in different stages of BC.
This study included 66 women with BC. The patients were categorized as follows : group 1 includes :22 patients with stage I disease ,group 2 includes: 22 patients with stage II disease ,and group 3 include: 22 patients with stage III disease .Group 4 includes :22 appare
... Show MorePatients with renal failure in the final stages undergo the treatment by hemodialysis. Hemodialysis is used to reinstate the intracellular and extracellular fluid environment, by propagation of molecules in solution through a semipermeable membrane along an electrochemical concentration gradient. Blood catching in the dialysis machine and the recurrent phlebotomy may lead to losing about 1-3 g of iron per year. Prohepcidin hormone is an acute phase protein (type II) that plays a major role in the systemic iron irregularities as it is a mediator of anemia in inflammation and regulator of iron metabolism. This study aims to evaluate the effect of hemodialysis on iron hemostasis and its relationship with prohepcidin as an inflammatory mark
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