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Determine Optimal Preventive Maintenance Time Using Scheduling Method
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In this paper, the reliability and scheduling of maintenance of some medical devices were estimated by one variable, the time variable (failure times) on the assumption that the time variable for all devices has the same distribution as (Weibull distribution.

The method of estimating the distribution parameters for each device was the OLS method.

The main objective of this research is to determine the optimal time for preventive maintenance of medical devices. Two methods were adopted to estimate the optimal time of preventive maintenance. The first method depends on the maintenance schedule by relying on information on the cost of maintenance and the cost of stopping work and access to the optimum time for maintenance, which achieves the lowest costs. The second method depends on the reliability function, which was to determine the optimal maintenance period, which then cost less Can. We also proved through this research that the method of scheduling is better than the method of relying on the reliability function because it depends heavily on the cost of maintenance.

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Publication Date
Tue Jun 01 2021
Journal Name
Baghdad Science Journal
The Energy Spectra and Heat Capacity of GaAs Gaussian Quantum Dot in an External Magnetic Field
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In this paper, a theoretical study of the energy spectra and the heat capacity of one electron quantum dot with Gaussian Confinement in an external magnetic field are presented. Using the exact diagonalization technique, the Hamiltonian of the Gaussian Quantum Dot (GQD) including the electron spin is solved. All the elements in the energy matrix are found in closed form. The eigenenergies of the electron were displayed as a function of magnetic field, Gaussian confinement potential depth and quantum dot size. Explanations to the behavior of the quantum dot heat capacity curve, as a function of external applied magnetic field and temperature, are presented.

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Publication Date
Tue Jan 31 2017
Journal Name
Journal Of Engineering
Remediation of Contaminated Soil with Petroleum Industrial Wastewater
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The contamination of soil with the wastes of oil industry products that are complex mixtures of hydrocarbons increased recently due to the large development of oil industries in Iraq. This study deals with the remediation of low permeability contaminated clayey soil by using the enhanced electrokinetic technique (EK). The contaminated soil samples obtained from Thi-Qar oil refinery plant in Al-Nassyriah city, where the byproducts of refinery plant are disposed into that site. The byproduct contaminant treated as total petroleum hydrocarbons (TPH) to avoid dealing and complexity of treating the individual minerals and compounds consisting the contaminant. The initial concentrations of TPH were (702.7, 1168, 1235) ppm in the contaminated s

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Publication Date
Thu Dec 31 2015
Journal Name
Al-khwarizmi Engineering Journal
Effect of Acetic Acid on Electrochemical Behavior of Sealed AA2319-T3 Al-Alloys Anodized in Phosphoric Acid Electrolytes
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Abstract

      The present study investigates the effect of acetic acid on corrosion behavior and its potential of hydrothermally sealed anodized AA2319-Al-alloys. Anodizing treatment was performed in stagnant phosphoric acid electrolyte with or without addition of acetic acid. Hydrothermal sealing was carried out in boiling water for each anodized specimen. The open circuit potential of the unsealed and sealed anodized samples was examined using open circuit potential measurement for the purpose of starting in scanning polarization diagrams. The potentiostatic polarization technique measurements were performed to assess corrosion behavior and sealing quality (i.e., degree of sealing) of

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Publication Date
Thu Jun 15 2023
Journal Name
Journal Of Baghdad College Of Dentistry
Molar tubes and failure rates–A review
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Objectives: To review the failure rates of molar tubes and the effect of molar tube base design, adhesive type, and bonding technique on the failure rates of molar tubes. Data: The revolution of molar bonding greatly impacted fixed orthodontic appliance treatment by reducing chair-side time and improving patient comfort. Even with the many advantages of molar bonding, clinicians sometimes hesitate to use molar tubes due to their failure rates. Sources: Internet sources, such as Pubmed and Google Scholar. Study selection: studies testing the bond failure rate of molar tubes. Conclusions: The failure rate of the molar tubes can be reduced and the bond strength of the molar tubes can be improved by changing the design of the molar tube base

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Publication Date
Wed Mar 18 2020
Journal Name
Baghdad Science Journal
Cr2O3:TiO2 Nanostructure Thin Film Prepared by Pulsed Laser Deposition Technique as NO2 Gas Sensor
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Pulsed laser deposition (PLD) technique was applied to prepared Chromium oxide (Cr2O3) nanostructure doped with Titanium oxide (TiO2) thin films at different concentration ratios 3,5,7 and 9 wt % of TiO2. The effect of TiO2 dopant on the average size of crystallite of the synthesized nanostructures was examined by X-ray diffraction. The morphological properties were discussed using atomic force microscopy(AFM). Observed optical band gap value ranged from 2.68 eV to 2.55 eV by ultraviolet visible(UV-Vis.) absorption spectroscopy with longer wave length shifted  in comparison with that of the bulk Cr2O3 ~3eV. This indicated that the synthesized samples a

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Publication Date
Sat Dec 20 2025
Journal Name
Iraqi Journal Of Pharmaceutical Sciences
Solubility and Dissolution Rate Enhancement of Simvastatin by Adsorption on Magnesium Aluminum Silicate
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Simvastatin (SIM), is an inactive lactone, anti-hyperlipidemic drug. The drug belongs to the class II group according to the biopharmaceutical classification system (BCS) with low bioavailability due to its low solubility. Adsorption technique is an effective technique for improving the solubility and dissolution rate of poorly soluble drugs by using the mesoporous silica. The present study aims to enhance the solubility and dissolution rate of SIM using such technique. Soluplus® and poloxamer 407 were used as surfactants besides magnesium aluminum silicate (MAS) as adsorbent. All the MAS loading SIM formulations were prepared by the solvent evaporation method in different drug: adsorbent: surfactant weight ratios, then evaluated f

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Publication Date
Tue Jul 02 2019
Journal Name
Fibers
Experimental Investigation of the Behavior of Self-Form Segmental Concrete Masonry Arches
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This research aims to introduce a new technique-off-site and self-form segmental concrete masonry arches fabrication, without the need of construction formwork or centering. The innovative construction method in the current study encompasses two construction materials forms the self-form masonry arches, wedge-shape plain concrete voussoirs, and carbon fiber-reinforced polymer (CFRP) composites. The employment of CFRP fabrics was for two main reasons: bonding the voussoirs and forming the masonry arches. In addition, CFRP proved to be efficient for strengthening the extrados of the arch rings under service loadings. An experimental test was conducted on four sophisticated masonry arch specimens. The research parameters were the Keystone thic

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Publication Date
Sun Jun 01 2025
Journal Name
Chalcogenide Letters
Fabrication and characterization of Se66S44-xAsx thin films chalcogenide
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In this paper, the effect of sulfur substitution by arsenic on the structural, optical properties of thin films of the trivalent chalcogenide Se66S44-xAsx at different concentrations (where x = 0, 8, 16, and 24 at %) was studied. Thin films with a thickness of (300±10 nm) were prepared using thermal evaporation of bulk samples. Structural examinations were performed using XRD and AFM techniques. All the studied film samples were amorphous in structure and the intensity of the crystalline parts was high in the range of 10-40. Also, in Atomic Force Microscopy (AFM). It was found that increasing the concentration of arsenic affects the structural parameters such as surface roughness, particle density, and average grain size. As the ar

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Publication Date
Sat Dec 31 2016
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Experimental Investigation of Mass Transfer for Copper Reduction by Weight Difference Technique
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An experimental analysis was included to study and investigate the mass transport behavior of cupric ions reduction as the main reaction in the presence of 0.5M H2SO4 by weight difference technique (WDT). The experiments were carried out by electrochemical cell with a rotating cylinder electrode as cathode. The impacts of different operating conditions on mass transfer coefficient were analyzed such as rotation speeds 100-500 rpm, electrolyte temperatures 30-60 , and cupric ions concentration 250-750 ppm. The order of copper reduction reaction was investigated and it shows a first order reaction behavior. The mass transfer coefficient for the described system was correlated with the aid of dimensionless groups as fo

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Publication Date
Tue Jun 01 2021
Journal Name
Iraqi Journal Of Physics
Effect of Transition Metal Dopant on the Electrical Properties of ZnO-TiO2 Films Prepared by PLD Technique
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In this article, the influence of group nano transition metal oxides such as {(MnO2), (Fe2O3) and (CuO)} thin films on the (ZnO-TiO2) electric characteristics have been analyzed. The prepared films deposited on glass substrate laser Nd-YAG with wavelength (ℷ =1064 nm) ,energy of (800mJ) and number of shots (400). The density of the film was found to be (200 nm) at room temperature (RT) and annealing temperature (573K).Using DC Conductivity and Hall Effect, we obtained the electrical properties of the films. The DC Conductivity shows that that the activation energies decrease while the σRT at annealing temperature with different elements increases the formation of mixed oxides. The Hall effect, the elec

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