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Studying and Modeling the Effect of Graphite Powder Mixing Electrical Discharge Machining on the Main Process Characteristics
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Abstract

This paper concerned with study the effect of a graphite micro powder mixed in the kerosene dielectric fluid during powder mixing electric discharge machining (PMEDM) of high carbon high chromium AISI D2 steel. The type of electrode (copper and graphite), the pulse current and the pulse-on time and mixing powder in kerosene dielectric fluid are taken as the process main input parameters. The material removal rate MRR, the tool wear ratio TWR and the work piece surface roughness (SR) are taken as output parameters to measure the process performance. The experiments are planned using response surface methodology (RSM) design procedure. Empirical models are developed for MRR, TWR and SR, using the analysis of variance (ANOVA).The best results for the productivity of the process (MRR) obtained when using the graphite electrodes, the pulse current (22 A), the pulse on duration (120 µs) and using the graphite powder mixing in kerosene dielectric reaches (82.84mm³/min). The result gives an improvement in material removal rate of (274%) with respect to the corresponding value obtained when copper electrodes with kerosene dielectric alone. The best results for the tool wear ratio (TWR) of the process obtained when using the copper electrodes, the pulse current (8 A), the pulse on duration (120 µs) and using the kerosene dielectric alone reaches (0.31 %). The use of graphite electrodes, the kerosene dielectric with 5g/l graphite powder mixing, the pulse current (8 A), the pulse on duration (40 µs) give the best surface roughness of a value (2.77 µm).This result yields an improvement in SR by (141%) with respect to the corresponding value obtained when using copper electrodes and the kerosene dielectric alone with the same other parameters and machining conditions.

Keywords: EDM, RSM, MRR, TWR, SR, AISI D2die steel, graphite powder mixing.

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Publication Date
Thu Jun 30 2016
Journal Name
Al-kindy College Medical Journal
Detection of Thrombi in Left Atrial chamber by Transoesophageal Ecchocardiography in patients suffer from Non-rheumatic Atrial Fibrillation
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Background: Background : Patients with non-rheumatic atrial fibrillation have high risk of thromboembolism especially ischemic stroke usually arising from left atrial appendage .Transoesophageal echocardiography provides useful information for risk stratification in these patients as it detects thrombus in the left atrial or left atrial appendage. Objective : This study was conducted at Al-Kadhimiya Teaching Hospital to assess the prevalence of left atrial chamber thrombi in patients with chronic non-rheumatic atrial fibrillation using transoesophageal echocardiography and its clinical significance as well as to verify the superiority of transoesophageal over transthoracic echocardiography in the detection of these abnormalities. Type of

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Publication Date
Wed Jan 01 2020
Journal Name
Journal Of Clinical And Experimental Dentistry
Resistance of bonded premolars to four artificial ageing models post enamel conditioning with a novel calcium-phosphate paste
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Background: This in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and Methods: Metal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was confirmed using FTIR. The bonded premolars were exp

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Publication Date
Mon Mar 15 2021
Journal Name
Al-academy
Semiotics of Musical Sign in Iraqi Pantomime Show (Ahriman) as a Model: علي عدي صاحب-شيماء حسين طاهر
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The musical sign was associated with the first appearances of acting that are based on human gestures and expressive and silent movements, and they contributed in accentuating and clarifying these gestures and explain their meanings and indications, and they remained with them until these gestures turned into artistic theatrical shows so that the musical sign would have many functions and constitute the main pillars for this kind of show.
The musical sign is a language not much different than the human language in the semiotic analysis. There has been an increased interest in it and its use in the mime shows by the graduates who realized its necessity and significance in the pantomime show intellectually, artistically and aesthetical

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Publication Date
Mon Nov 05 2018
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Molecular Characterization of Malassezia furfur isolated from patients with pityriasis versicolor compared to healthy control in Baghdad, Iraq
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Background: Humans skin, is the largest organ of the integumentary system, it has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Pityriasis versicolor is the prototypical skin disease etiologically connected to Malassezia species. Malassezia furfur is the primary causative agent of pityriasis versicolor which causes either hyperpigmentation or hypopigmentation of the skin.
Objective: To identify of Malassezia furfur associated with pityriasis versicolor patients and healthy control by using molecular detection methods.
Material and Methods: Sixty patients suffering from pityriasis versicolor disease who attended Medical Imammaine Kadhmain City from beginning of 1st Dece

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Publication Date
Mon Mar 13 2017
Journal Name
Journal Of Baghdad College Of Dentistry
Selected Salivary Biomarkers in Relation to Work-related Musculoskeletal disorders among a Group of Dentists in Baghdad City
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ABSTRACT Background: work-related musculoskeletal disorders represent an important occupational health issues among dentists especially neck and low back complaints. Biomarkers of tissue damage as results of occupational physical demands could be used for detection of work related musculoskeletal disorders. Aim: The aim of this study was to assess work- related musculoskeletal disorders, physical work load index, selected salivary biomarkers (Creatine kinase and C - reactive protein) and to find the relation among them. Subjects and Methods: Study participants are consisted of 112 dentists. They were selected from college of dentistry /Baghdad University, health care center in Bagdad city. They were of both gender and aged between 40-45 yea

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Publication Date
Fri Jan 10 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Distribution of tooth wear among institutionalized residents (50-89 years old) in Baghdad city\ Iraq (Cross-sectional study)
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Background: Tooth wear is one of the most common problems in the older dentate population which results from the interaction of three processes (attrition, abrasion and erosion) and it affects all societies, different age groups, and all cultures. This study was achieved to evaluate the prevalence and distribution of tooth wear among institutionalized residents in Baghdad city\ Iraq. Subjects and Methods: This survey was accomplished on four private and one governmental institution in Baghdad city. One-hundred twenty three (61 males, 62 females) aged 50-89 years were participated in this study. The diagnosis and recording of tooth wear were according to criteria of Smith and Knight. Results: The prevalence of tooth wear was 100% with a mean

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Publication Date
Sun Mar 07 2010
Journal Name
Baghdad Science Journal
Synthesis of New Heterocyclic Derivatives from 4-(3, 5-Dimethyl-1-phenyl-1H-pyrazol-4-ylazo)- benzoic acid
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In this work pyrazolin derivatives were prepared from the diazonium chloride salt of 4-aminobenzoic acid. Azo compounds were prepared from the reaction of an ethanolic solution of sodium acetate and calculated amount of active methylene compound namely, acetyl acetone to obtain the corresponding hydrazono derivative (1). Cyclocondensation reaction of compounds (1) with hydrazine hydrate and phenyl hydrazine in boiling ethanol affording the corresponding pyrazoline-5-one derivatives of 4-aminobenzoic acid (2,3). Then compound (3) was reacted with thionyl chloride to give the corresponding acid chloride derivative(4), followed by conversion into the corresponding acid hydrazide derivative (5) carboxylic acid thiosemicarbazide (11), esters

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Publication Date
Thu Apr 13 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Determination of Sialic acid, Paraoxonase-1and IgG levels in Patients with Polycystic Ovary Syndrome in Messan Female Patients
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    Polycystic ovary syndrome (PCOS) is a heterogeneous disorder . PCOS affects 6–10% of women during their reproductive life. Patients with PCOS are in the high risk for coronary heart disease because of their abnormal lipid profile, insulin resistance and obesity. The present study aimed to shed a light on the contribution of  sialic acid, paraoxonase and immunoglobulin G as a clinical indicator in the pathogenesis of PCOS. Seventy five female patients with age range (16-38) years taken from Al-Sadder Teaching Hospital and AlZahrawi Hospital in Governorate of    Messan through the period from July 2013 to December 2013 and twenty five apparently health subject as a control group were

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Publication Date
Tue Jan 02 2018
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Humoral immune factor changes in group of patients with Non-muscle invasive bladder cancer treated with intravesical therapy.
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Background: Bladder cancer (BC) one of the most common urologic cancer characterized by the highest recurrence rate, many types belong to BC, but most common of them worldwide are transitional cell carcinoma(TCC) which constitute about 90-95% cases, squamous cell carcinoma (SCC) and adenocarcinomas
Objective: This study was designed to evaluate parameters of humoral immunity in Non-muscle invasive (superficial or early) bladder cancer patients in Iraq that may provide a new insight into the future of immunotherapies development and BC management.
Materials and methods: Fifty-nine volunteer's patients ranged from 24 to 83years old, and 30 control individuals ranged from 51-80 years old, who attended and admitted to Hospital of Gazi

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Publication Date
Sat Apr 30 2022
Journal Name
Iraqi Journal Of Science
Lithology Evaluation of Nahr Umr Formation Using AI with Vp/Vs relationship at Amara Oil Field, Southern Iraq
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The litholog     of Nahr Umr Formation was evaluated using the Acoustic Impedance (AI), Vp/Vs ratio cross plot colored by petrophysical properties (Vsh, PHIT, PHIE, and Sw) in Am-6-Am-10 wells. Bulk density is an important physical property that reflects matrix density and fluid density that exist in rocks pores. It is used as the main parameters to estimate physical characteristics (porosity, water saturation, shale volume, and others). AI was calculated using RHOB and VP logs. Shear velocity was calculated using Greenberg Castagna equations used for estimating the Vp/Vs ratio and the result Showed that the Nahr Umr Formation is composed of two main lithological units. The upper unit (depth 3540m -3672m) is composed of limestone (li

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