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Simulation on Rotation Curve of Spiral Galaxies
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Abstract<p>The problem of dark matter in galaxies is still one of the most important unsolved problems in the contemporary extragalactic astronomy and cosmology. The existence of a significant dynamic difference between the visible mass and the conventional mass of galaxies firmly establishes observational result. In this paper an unconventional explanation will be tested as an alternative to the cold dark matter hypothesis; which is called the modified Newtonian dynamics (MOND).</p><p>In this paper covers the simulation of galactic evolutions; where the two hypotheses are tested via the rotation curves. N-body simulation was carried adopting different configuration like a hot disk, elliptical (with arms and without arms) with a different parameter that covers the objects distribution, masses and velocities. It is shown from the simulation results that the MOND hypothesis has generated better rotation curves than the Newtonian theorem. Moreover, the appropriate configuration and parameters for spiral galaxy are investigated. It is shown that this assignment has not been easy; because the problem is very delicate and unstable.</p>
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Publication Date
Thu Mar 31 2016
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Synergistic Effect of Potassium Iodide on Inhibitive Performance of Propyl Alcohol during Corrosion of Mild Steel in 1.0M HCl
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   The inhibition of mild steel corrosion in 1.0M HCl by 1-propanol and the synergistic effect of potassium iodide (KI) was investigated using weight loss and polarization techniques in the temperature range (30 ‒ 50) ̊ C. A matrix of Doelhert to three factors was used as the experimental design, adopting weight loss results as it permits the use of the response surface methodology which exploited in determination of the synergistic effect as inhibition on the mild steel. The results were confirmed using electrochemical polarization measurements. Experimental results showed that the inhibition efficiency (IE%) increases with increase in concentration of inhibitor and with increasing of temperature. The addition iodide ions t

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Publication Date
Sun Jun 06 2010
Journal Name
Baghdad Science Journal
Effect of Chromium on Growth of green ALGA SCENEDESMUS QUADR ICAUDA (TURP.) DE BERB. With increase of nitrogen concentration
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The study was conducted to identify the toxicity of chromium on scenedesmus quadricauda algae alone and in the presence of nutrient metal (Nitrogen). Different concentrations of chromium (0.5, 1.5 , 2.5, 3.5 , 4.5mg/L) were used and the presence nitrogen is (5 ,10 ,50 ,100mg/L) on cultur media(chu-10) with used for cultivation of the algae in controlled conditions(25oC , light intensity 380 –?E/m2 /s. The results showed increasing in the toxicity of the metal when is alone , excess of concentrations an time of exposure. The growth rate decreased from 0.44 to 0.06 cell/ hour after 12 day of the biging of the experiment and of concentrate 4.5 mg/L of chromium. The intermediate active concentrations of the chromium(EC50) was increase

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Publication Date
Sun Oct 01 2023
Journal Name
Baghdad Science Journal
The Influence of Ablation Speed on the Synthesis of Carbon Nanostructures Via Pulsed Laser Ablation of Asphalt in Ethanol
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Pulsed liquid laser ablation is considered a green method for the synthesis of nanostructures because there are no byproducts formed after the ablation. In this paper, a fiber laser of wavelength 1.064 µm, peak power of 1 mJ, pulse duration of 120 ns, and repetition rate of 20 kHz, was used to produce carbon nanostructures including carbon nanospheres and carbon nanorods from the ablation of asphalt in ethanol at ablation speeds of (100, 75, 50, 10 mm/s).  The morphology, composition and optical properties of the synthesized samples were studied experimentally using FESEM, HRTEM, EDS, and UV-vis spectrophotometer. Results showed that the band gap energy decreased with decreasing the ablation speed (increasing the ablation time), the mi

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Publication Date
Fri Dec 15 2017
Journal Name
Journal Of Baghdad College Of Dentistry
The Effect of Addition of Zirconium Nano Particles on Antifungal Activity and Some Properties of Soft Denture Lining Material
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Background Microorganisms and fungal growth especially Candida albicans, on soft denture lining material are the most common problem which can lead to chronic mucosal inflammation. The aim of this study was to evaluate the effect of zirconium nanoparticles into acrylic-based heat cured soft denture lining material against Candida albicans, and the amount of zirconium ion release of soft liner/ZrNPs composite. Furthermore, evaluate shear bond strength after ZrNPs addition to soft liner. Materials and methods: Zirconium nanoparticles were added into acrylic-based soft denture liner in various percentages (1%, and 1.5% by weight). Two hundred and fifty specimens were arranged and isolated into four groups as per the test to be done The antifu

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Publication Date
Mon May 27 2019
Journal Name
Al-khwarizmi Engineering Journal
Effect of Using Air Guide Net in Front of the Condenser on the Performance of Automobile Air Conditioning System
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The work of this paper is an investigation to improve the condenser performance of the automobile air conditioning system by enhancing the air-side heat transfer from the condenser through the use of an air guide net installed in front of the condenser face which is basically an aluminum plate having a circular entrance shape for the air passage.  The A/C system was examined under two types of test. The first test was conducted the air guide net, while the second was done with the air guide net. The performances of the A/C system under these tests were compared. For the second type of test, the experiment was carried out with three different size of air guide net, three different circular diameters (2, 3 and 3.5 cm) a

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Publication Date
Mon Dec 05 2022
Journal Name
Baghdad Science Journal
Effect of Secondary Metabolite Crude of Metarhizum anisopliea Fungus on the Second Larval Stage of the Housefly Musca domestica
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         The house flies Musca domestica )Diptera:musidae) are the primary carrier of many pathogens such as cholera, typhoid, anthrax, and others. The use of chemical pesticides as a basic method of control leads to many problems at the environmental and health level. The use of safe alternatives to chemical pesticides has become an urgent necessity. The research aims to find biological alternatives that are environment-friendly and non-pathogenic to humans in controlling house flies through the possibility of extracting and diagnosing some secondary metabolites produced by the fungus Metarhizium anisopliae and testing their effects on the second larval stage of house flies using different treatment methods that include

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Publication Date
Fri Jul 17 2026
Journal Name
Journal Of Baghdad College Of Dentistry
An Evaluation the Effect of Alcohol Presence in Mouth Washes on Force Degradation of Different Configurations of Elastomeric Chains
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Background: Elastomeric chains are one of the most commonly used force delivery systems. They have the ability to exert a continuous force, convenience of use, compatibility to oral environment and cost effectiveness but one of the inherited disadvantages is force degradation. Materials and methods: This in vitro study was designed to evaluate the effect of alcohol presence in mouthwashes on force decay of different configurations of clear elastomeric chains from (Ortho Technology company) which are: closed , short and long under the effect of time at (Initial, 1, 2, 3 and 4 weeks) intervals with exposure to different chemical solutions. A total (540) modules of elastomeric chains of three different types (long, short and closed) trans

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Publication Date
Wed May 01 2024
Journal Name
Journal Of Physics: Conference Series
Study of The Effect of Concentration on The Efficiency of The Sensitive N749-TiO<sub>2</sub> Solar Cell
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Abstract<p>In this research, we studied the effect of concentration carriers on the efficiency of the N749-TiO<sub>2</sub> heterogeneous solar cell based on quantum electron transfer theory using a donor-acceptor scenario. The photoelectric properties of the N749-TiO<sub>2</sub> interfaces in dye sensitized solar cells DSSCs are calculated using the J-V curves. For the (CH3)3COH solvent, the N749-TiO<sub>2</sub> heterogeneous solar cell shows that the concentration carrier together with the strength coupling are the main factors affecting the current density, fill factor and efficiency. The current density and current increase as the concentration increases and the </p> ... Show More
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Publication Date
Mon Dec 20 2021
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
IMPACT OF THARTHAR ARM WATER ON COMPOSITION AND DIVERSITY OF COPEPODA IN TIGRIS RIVER, NORTH OF BAGHDAD CITY, IRAQ
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This study is considered to be the first on this sector of Tigris River after 2003, to evaluate the effect of Tharthar Arm on the composition and diversity of Copepoda in Tigris River. Six sampling sites were selected; two on the Tharthar Arm and four sites along the Tigris River, one before the confluence as a control site and the others downstream the confluence; thirty-five copepod taxa were recorded, 34 taxa in the Tigris River and 25 taxa in the Tharthar Arm.
The highest density of Copepoda was in site 2 at Tharthar Arm was 265584.2 Ind./m3 lead to an increasing in Copepoda density in Tigris River from 63878.2 Ind./m3 in site 1 before the confluence to 127198.3 Ind./m3 in site 4 immediately downstream the confluence. Also, the me

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Publication Date
Tue Dec 11 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Impact of Different Degrees of Uterine Prolapse on Sexual Function of Women at Teaching Hospitals in Al-Hilla City
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Background: Women sexuality is basic right and it plays a major role in women's Health aspects. Up is one of the factors that lead to sexual dysfunction while the incidence of it is rising as UP severity being more. Objectives: To assess the impact of different degrees of uterine prolapse on sexual function of women at teaching hospitals in AL-Hilla City. Methodology: A descriptive analytical study was conducted from 1ST Feb to 10th Jun /2014 to assess the impact of different degrees of uterine prolapse on sexual function for women who attend to consultant clinic at teaching hospitals in AL-Hilla City

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