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Dijlah Journal

مجلة دجلة

ISSN: 44446583
Publisher: Dijlah University College
Faculty:
Language: English

This journal is Open Access

About

Dijlah university journal for social sciences and sciences, Dijlah university journal accepts researches in medical and applied sciences in general beside the social sciences researches.

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Contact info

journal@duc.edu.iq

Table of content: 2019 volume:2 issue:1

Article
Evaluation of Microstructure and Hot Corrosion Behaviour of YPSZ / Al2O3Composite Plasma Sprayed Coatings at 900oc by Molteneutectic vana- date-SulfateSalt

Authors: Mohammed J Kadhim --- Sami A Ajeel --- Ali M Resen
Pages: 3-18
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Abstract

This work is aimed to study effect of alumina coating on the partially stabilized zirconia alumina composite (YPSZ/ Al2O3) on the microstructure, phase transformation and hot corrosion perfor- mance of eutectic molten salt V2O5 + 45 wt% Na2SO4 and comparing with conventional YSZ.Both the pure alumina and YPSZ are sprayed by using atmospheric plasma spray APS. Hot corrosion for composite is done by exposing the samples to an isothermal air furnace testing at900 °C for different exposure times of40 and 80 hours. Upper surface plan views of the coatings are exam- ined using SEM. The hot corrosion test products are determined using EDS, EPMA and XRD. The results indicate the higher hot corrosion resistance of YSZ/ Al2O3 composite coatings compared with conventional YSZ sprayed coatings. Degradation of YSZ due to the presence of eutectic harsh salt attack is occurred by destabilization of yttria from the zirconia yttria coatings. This will lead to disrupt transformation from metastable tetragonal phase (t’) to monoclinic phase (m). the corrosion products of YVO4produce by leaching process. During exposure the composite to the molten salt the Al2O3is reacted with vanadate to form a low-melting liquid eutectic phase, lead- ing to dissolution of Al2O3in molten NaVO3Na2O–V2O5–Al2O3. The pores and cracks within the YSZ coating are filled with Al2O3. The absences of leaching of yttria in under layer for composite coatings is related to the absence of pockets of open porosity and cracks due to elimination after alumina layer applied.


Article
Mechanical Properties of Weld Joint in Refrigeration Tubes Welded by TIG Process

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Abstract

This study involves the welding technology of carbon steel pipes which is widely used in many engineering applications, in particular refrigeration systems and boilers. The chemical composition of this metal shows that are close to steel grade A192 according to ASTM standards. This metal shows an excellent weldability and enhanced potential for the use of high strength TIG weld consumable. TIG weld filler type ER70S-6 is used to join two pieces of steel pipes using TIG welding machine. This experimental work also involves the evaluation of the integrity and mechanical prosperities of the weld joint. That was done by conducting a several destructive and non-destructive tests on the weld joints such as, Tensile, bending, hardness, x-ray and Liquid penetrant). The tests program confirmed that, the weld joint maintains a good mechanical properties and acceptable weld defect


Article
Mechanical Properties Control Of Low And Medium Carbon Steel Using Feed Forward Neural Networks

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Abstract

Two feed forward multilayer neural network (FFMNN) architecture have been constructed. The first model has two hidden layers, 20 neurons for first layers and 30 neurons for second layers. The first model utilized to control the mechanical properties (yield strength, tensile strength and hardness) which are the inputs to this model. The model gives the carbon percentage and the heat treatment type and temperature as response to the required mechanical properties. The second model is implemented to predict the effect of carbon, quenching and tempering temperature on mechanical properties of both tensile strength and hardness of low and medium carbon steel. It has two hidden layers, 30 neurons for first layers and 60 neurons for second layers. In addition, the effect of different carbon percentages and heat treatment temperature for quenching were stud- ied on the mechanical properties of low to medium carbon steel. The results of Vickers hardness showed that hardness, yield strength and tensile strength were increased with increasing the car- bon percentage, quenching temperature and decreasing the tempering temperature. The neural networks models showed good agreements with experimental data. The correlation coefficients for the first model versus the experimental data are 0.9917, 0.9782 and 0.9954 for yield strength, tensile strength and Vickers hardness respectively. Higher correlation coefficients were obtained for the second modelling


Article
The Correlation between obesity & ABO Blood Group of a sample of students of the Faculty of Education at the Univer- sity of Wasit

Authors: Jiheel M.Jadwa.
Pages: 37-44
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Abstract

This study was conducted to determine the prevalence of obesity among young people and to determine whether there was any association between overweight and obesity with the ABO blood group. The total number of students tested was 200 students (100 from each gender), in aged between 20 and 23 years. They took the weights and length of the individuals and entered the body mass index (BMI) equation according to the index of body mass by dividing the weight in kilograms per square meter in length and comparing the values calculated by the standard values shown in Table (3) and calculating the percentages for each weight category. Blood groups were recorded from the information taken for the some research members, and the test was performed in a way that matched those who did not know their blood samples and other random samples to verify the credibility of the information. The results were identical to the information obtained directly. The results were as follows: 2%,the proportion of individuals with a weight below normal distributed equally between males and females and 71% is the proportion of individuals with normal weight, boys scored the highest percentage of girls while the proportion of people who suffer from obesity is 25% and the increase in girls by 2% of male. At the level of the blood groups, O group was the most overweight, followed by A, B, and AB, and only 4% in the O group.

Keywords

BMI --- ABO blood --- cancer --- malignant diseases


Article
Preparation and Characterization of ceramic - metal Functionally Graded Materials for Hip Joint Implants

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Abstract

The present study included preparation and characterization of step-wise functionally graded materials (FGMs) for hip joint replacements, prepare by using powder technology technique. ceramic – metal FGMs specimens (AZT Group) that made from nano Al2O3, nano 3YPS-ZrO2 and Ti – alloy (Ti-6Al-4V), consist of 10 layers begins with 100% Ti – alloy that gradually decreases and Al2O3and 3YPS-ZrO2 increases, finally ends by 100 %Al2O3. Physical tests for AZT – Group were done in order to characterize FGMs prepared, which includes apparent density & porosity for green compact and for sintered compacts also relative apparent density percentage, all physical tests showed increase in apparent and relative apparent density percentage after sintering process in a range (93-98)% and decrease in porosity (25- 35)% as a range also after sintering process, which it’s a great evident that the time and temp. of sintering process chose carefully and gave optimum properties of FGMs specimens. Mechanical tests such as Vickers microhardness, fracture toughness and residual stresses used to characterize prepared of FGMs. All mechanical tests are presented a gradient in results through the cross – section of FGMs specimens as expected from the gradient of composition that shows a smooth transition from layer to another that eliminate the sharp transition. X-rays diffraction was done to investigate phases appears and SEM and EDS analysis also were done for AZT1, which shows higher properties among their groups, display good distributed of 3YPS – ZrO2 from EDS analytic and there were no agglomerates, which its good evidence of good mixing process and sintering practice.

Keywords

Alumina --- 3YPS-zirconia --- Ti-6Al-4V --- hip joints


Article
Evaluation and Analysis of Nonlinear Bipolar Transistor Performance under High Temperature Using MATLAB

Authors: Mohammed W. Hussein
Pages: 59-70
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Abstract

The Design and Analysis of Nonlinear Bipolar Transistor Performance Using MATLAB is present in this paper. The bipolar junction transistor (BJT) operation at non- linear circuit is representing a vital part in some application. Many BJT model has been introduced such as small signal, charge control and each model has its own area of application. The proposed model of nonlinear BJT based on circuit of R1 and R2 set the normal operation point and small signal gain is approximately set under ration R3/R4. A decoupling capacitor of 1uF has chosen to ignore the impedance at 1 KHz to generate frequency response. Novel development used for the characteristics mechanism replica and its performance representation of power transistor with enough memory effects is evaluated and examined. The electrical memory effects and thermal impact on the transistor presentation is compared. The results show important information about BJT performance and proper applications associated with each type under 45-90 OC.


Article
Study and Evaluation of the low (LWC) Density Production Characteristics

Authors: Amenah E. mohammed redha
Pages: 71-81
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Abstract

This paper presents the study and evaluation of low lightweight concrete (LWC) density production under multi stage casting process. The lightweight aggregate type and associated volume fraction mix is determined by the lightweight concrete density. In traditional mixing process of concrete, the minimization of the density clearly required high volume fraction which will causes aggregate segregation. The multi stage casting procedure occupy inserting lightweight (LW) aggregates in casing following satisfying in residual interstitial void by means of cementations grout with a low density. Consequently, these methods produce low compressive strength and enhanced weak point. Thus, the suggested casting technique could have a practical for developed non-structural rudiments and structural compound that require minimum density. The results show promising methods to support many projects that required strength more than 20 MPa for house slabs, driveways and footpaths.

Keywords

LWC --- Lightweight --- Low density --- LWC Aggregate


Article
The Analysis of Electromagnetic Accelerator

Authors: A.M. Suhail --- Hussien A. Mohammed
Pages: 82-86
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Abstract

The electrical and mechanical construction of cheap and simple laboratory model of electromagnetic accelerator is presented. The system was operated at low energy of about 1.5KJ, producing a projectile velocity of about 50 m/sec. The system analysis based on a developed mathematical model shows the .variation of the current and the velocity as a function of the time

Table of content: volume:2 issue:1