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.
Problem of water scarcity is becoming common in many parts of the world. Thus to overcome this problem proper management of water and an efficient irrigation systems are needed. Irrigation with buried vertical ceramic pipe is known as a very effective in management of irrigation water. The two- dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the software HYDRUS/2D to predict empirical formulas that describe the predicted results accurately. Different values of pipe lengths and hydraulic conductivity were selected. In addition, different values of initial volumetric soil water content were assumed in this simulation a
... Show MoreThe pumping station became widely used in many fields. Free surface vortices at intakes of pumps are not favorable. It may cause noise, excessive vibration, damage to the pumping structure, reduction in efficiency and flow for hydro-turbines, etc. One of the important problems encountered during the pump intake design is the depth of submergence and other design parameters to avoid strong free-surface vortices formation. This study aims to compute the critical submergence depth with some geometrical and hydraulic limitations by using Computational Fluid Dynamic (CFD) package. The mathematical model was validated with a laboratory model that had been conducted. The model of three intake pipes was investigated under five d
... Show MoreA numerical study has been carried out to investigate heat transfer by natural convection and radiation under the effect of magnetohydrodynamic (MHD) for steady state axisymmetric twodimensional laminar flow in a vertical cylindrical channel filled with saturated porous media. Heat is generated uniformly along the center of the channel with its vertical surface remain with cooled constant wall temperature and insulated horizontal top and bottom surfaces. The governing equations which used are continuity, momentum and energy equations which are transformed to dimensionless equations. The finite difference approach is used to obtain all the computational results using the MATLAB-7 programming. The parameters affected on the system are Rayl
... Show MoreThe two-dimensional transient heat conduction through a thermal insulation of temperature dependent thermal properties is investigated numerically using the FVM. It is assumed that this insulating material is initially at a uniform temperature. Then, it is suddenly subjected at its inner surface with a step change in temperature and subjected at its outer surface with a natural convection boundary condition associated with a periodic change in ambient temperature and heat flux of solar radiation. Two thermal insulation materials were selected. The fully implicit time scheme is selected to represent the time discretization. The arithmetic mean thermal conductivity is chosen to be the value of the approximated thermal conductivity at the i
... Show MoreThis study was designed to determine the correlation between Y chromosome azoospermia factor (AZF) subregions microdeletions and oligozoospermia in infertile men. Subjects included 50 infertile men with oligozoospermia who had been referred to the Fertility Center and infertility treatment in Kamal Al-Samarrai Hospital\Baghdad health office-Iraq. DNA was extracted from blood samples. Polymerase chain reaction (PCR) amplification of 3 loci spanning the AZFa, AZFb and AZFc subregions of the Y chromosome using sY84, sY127 and sY254 and were performed. The frequency of deletions involving AZFa subregion of the Y-chromosome was found in twelve of the patients (24%) in oligozoospermic infertile Iraqi men. While the other subregion (AZFb and AZ
... Show MoreBackground: Cigarette smoking is an important risk factor that has a clear strong association with the prevalence and severity of chronic periodontitis (CP). Salivary biochemical parameters may be affected by both smoking and CP together. Materials and methods: Eighty systematically healthy male patients were included in this study. They were grouped based on their periodontal and smoking status. Unstimulated whole saliva (UWS) was collected from all subject. Salivary flow rate (FR) was measured during sample collection. Parameters such as salivary pH, total protein (TP), albumin (Alb), total fucose (TF), protein bound fucose (PBF) and C-reactive protein (CRP) were estimated. Results: Salivary flow rate was not altered regarding to smoking
... Show MoreInsulin-induced hyperglycemia is the hallmark of diabetes mellitus (DM), including various metabolic disorders. Diabetic people are more likely to develop dyslipidemia, hypertension, and obesity. Type 2 diabetes (T2DM), the most common illness, is generally asymptomatic in its early stages and can go misdiagnosed for years. Diabetes screening may be beneficial in some cases since early identification and treatment can lessen the burden of diabetes and its consequences. This study aimed to find the relationship between Glycated hemoglobin (HbA1c) and lipid profile components in T2DM patients. This descriptive-analytical and cross-sectional study was performed on the control group and T2DM patients in Medical City in Baghdad be
... Show MoreSystemic lupus erythematosus (SLE) is a multifactorial chronic autoimmune disease, with a wide spectrum of effect. The main feature of the disease is the production of a wide variety of autoantibodies as a result of immune tolerance loss. The work aims to evaluate the miRNA-146a gene polymorphism potential association with disease activity and chronicity changes in SLE patients. The study included 100 SLE patients and 50 matched controls. The systemic lupus erythematosus disease activity index (SLEDAI) was assessed. The single nucleotide polymorphism (SNP) of miR-146a gene (rs2910164) polymorphism was assayed by polymerase chain reaction (PCR) and sequencing technique in patients and control. 100 SLE pati
... Show MoreBackground: Polycystic ovary syndrome (PCOS) is a common endocrinopathy in women of
reproductive age with primary features of infertility, menstrual irregularity, and clinical or biochemical
evidence of hyperandrogenism (hirsutism, acne and high androgen level). Vitamin D has a role in the
development of metabolic and endocrine abnormalities in PCOS mediated by insulin resistance.
Objective: Measure serum 25-hydroxy vitamin D levels in women with polycystic ovary syndrome and
compare their levels with age and body mass index matched healthy controls. Also, assess the
correlation between insulin resistance and 25-hydroxy vitamin D among women with PCOS.
Subjects and Methods: Eighty eight women were involved in this st