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Thermo-mechanical properties of cubic lanthanide oxides
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This contribution investigates the effect of the addition of the Hubbard U parameter on the electronic structural and mechanical properties of cubic (C-type) lanthanide sesquioxides (Ln2O3). Calculated Bader's charges confirm the ionic character of Lnsingle bondO bonds in the C-type Ln2O3. Estimated structural parameters (i.e., lattice constants) coincide with analogous experimental values. The calculated band gaps energies at the Ueff of 5 eV for these compounds exhibit a non-metallic character and Ueff of 6.5 eV reproduces the analogous experimental band gap of cerium sesquioxide Ce2O3. We have thoroughly investigated the effect of the O/Ce ratios and the effect of hafnium (Hf) and zirconium (Zr) dopants on the reduction energies of CeOx configurations. Our analysis for the reduction energy of CeO2, over a wide range of temperatures displays that, shuffling between the two +4 and +3 oxidation states of Ce exhibit a temperature-independent behaviour. Higher O/Ce ratios necessitate lower reduction energies. Our results on Cesingle bondHfsingle bondZrsingle bondO alloys are in reasonable agreements with analogous fitted values pertinent to lowering reduction energies and shrinkage in lattice parameters when contrasted with pure CeO2. Structural analysis reveals that Hf and Zr atoms in the solid solution are shifted towards the nearest vacancies upon reduction. It is hoped that values provided herein to shed an atomic-base insight into the reduction/oxidation thermodynamics of increasingly deployed catalysts for environmental applications.

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Publication Date
Wed Jun 18 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of nano surface modification on CPTi dental implant using chemical method: mechanical and histological evaluation
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Background The application of nanotechnology to biomedical surfaces is explained by the ability of cells to interact with nanometric features. The aim of this study was to consider the role of nanoscale topographic modification of CPTi dental implant using chemical etching method for the purpose of improving osseointegration. Materials and methods: Commercial pure titanium rod was machined into 20 dental implants. Each implant was machined in diameter about 3mm, length of 8mm (5mm was threaded part and 3mm was flat part). Implants were prepared and divided into 2 groups according to the types of surface modification method used: 1st group (10 implant) remained without nano surface modification (control), 2nd group include (10 implant) etche

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Publication Date
Wed May 01 2019
Journal Name
Thin Solid Films
Studies of annealing impact on the morphological, opto-dielectric and mechanical behaviors of molybdenum-doped CrN coatings
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Publication Date
Tue Sep 11 2018
Journal Name
Iraqi Journal Of Physics
The effects of silica addition on the structural, electrical and mechanical characteristics of MgAl2O4 spinel ceramic phase
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The ceramic compound Mg1-xSixAl2O4 (x= 0, 0.1, 0.2, 0.3, 0.4) was prepared from nano powder of Al2O3 and MgO doped with Nano powder of SiO2 at different molar ratios. The specimens were prepared by standard chemical solid reaction technique and sintered at 1450 oC. Structure of the specimens was analyzed by using X-ray diffraction (XRD). The X-ray patterns of the specimens showed the formation of pure simple cubic spinel structure MgAl2O4 phase with space group of ̅ . The average grain size and surface topology were studied by atomic force microscopy. The results showed that the average grain size was about 73-90 nm. The DC electrical properties of the specimen were measured. The apparent density was found to increase and the porosity a

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Publication Date
Mon Oct 04 2021
Journal Name
Journal Of Petroleum Exploration And Production Technology
Perforation location optimization through 1-D mechanical earth model for high-pressure deep formations
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Optimum perforation location selection is an important study to improve well production and hence in the reservoir development process, especially for unconventional high-pressure formations such as the formations under study. Reservoir geomechanics is one of the key factors to find optimal perforation location. This study aims to detect optimum perforation location by investigating the changes in geomechanical properties and wellbore stress for high-pressure formations and studying the difference in different stress type behaviors between normal and abnormal formations. The calculations are achieved by building one-dimensional mechanical earth model using the data of four deep abnormal wells located in Southern Iraqi oil fields. The magni

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Publication Date
Sun Jun 11 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Quantum Mechanical Study Using the DFT Method of the Structure, Stability and Vibrationalmosion of the Ketones of Cyclopropane
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  In this study a DFT calculation on cyclopropanone, cyclopropandione and cyclopropantrione molecules was performed using the basis function 6-31G ** / MP2 and exchange correlation potential B3-LYP. The results showed that the ground state of all molecules geometry belong to the point group 𝐶2𝑣where a vibronic coupling between the vibrational motion with the electronic ground state in the molecule C3O3 this leads to a reduction in symmetry of the molecule from𝐷3ℎto 𝐶2𝑣, the driving force of this process is accessing to the electronic configuration complies with Hückel aromatic systems with two electrons. Also in this, study the normal modes of vibration, frequencies, intensities and symm

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Publication Date
Wed Dec 01 2010
Journal Name
Al-khwarizmi Engineering Journal
Properties of High Performance Concrete
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The research deals with a new type of high-performance concrete with improved physical properties, which was prepared by using metal additives minutes (Metakaolin) and by studing their impact on the properties of mortar and concrete high-performance through destructive and non destructive tests. This type of concrete is used broadly in public buildings and in other structures . The research involved a number of experiments such as finding the activity index of burned at a temperature of 750 º C according to the standard ( ASTM C-311/03), as well as casting models for the cubic mortar mixtures and concrete containers at different rates of metakaolin ranging between (5% - 20%) as an added part to the cement mix to get a high- compressive

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Publication Date
Wed Apr 19 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Effect of Doping by Sr on the Structural, Mechanical and Electrical Characterization of La1Ba1-xSrx Ca2Cu4O8.5+δ
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       The Sr doped La1Ba1-xSrx Ca2Cu4O8.5+δ samples with 0 ≤ x ≤ 0.3 had been prepared using the solid state reaction. The samples were claimed at 800°C for 3hr, palletized and sintered at 860°C for 20hr in air . Dielectric constant and loss by means of capacitance have been investigated with frequencies in the range of 1kHZ to 1MHZ for our samples at room temperature. Also, Shore hardness has been measured. The dielectric constant and loss decrease slightly with the increase of frequency for all compounds. Additionally, the partial substitution of Sr+2 into Ba+2 sites never have effect on the dielectric properties. X-ray diffraction (XRD) analysis showed a tetragonal structure and the

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Publication Date
Wed Sep 14 2016
Journal Name
Journal Of Baghdad College Of Dentistry
Mechanical Evaluation of Pure Titanium Dental Implants Coated with a Mixture of Nano Titanium Oxide and Nano Hydroxyapatite
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Background: The type of dental implant surface is one of many factors that determine the success of implant restoration. This study aimed to study the effect of mixture of nano titanium oxide with nanohydroxyapatite coating of screw shaped CPTi dental implant on bond strength at bone implant interface by torque removal test related to two healing periods (2 and 6 weeks). Materials and methods: Dip coating process was performed to get an even coating layer on CPTi screws. X-ray diffraction (XRD) analysis and microscopical examination were performed on the coating surfaces of the CPTi. The tibia of 10 white New Zealand rabbits was chosen as implantation sites. The tibia of each rabbit received two screws, one was coated with mixture of nanoT

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Publication Date
Wed Jan 01 2020
Journal Name
Journal Of Mechanical Engineering Research And Developments
The perfect position of electrical components on PCBs in communication system industry from the mechanical aspects' viewpoint
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Publication Date
Thu Jul 16 2020
Journal Name
Polymer Bulletin
Fabrication and evaluation of structural, thermal, mechanical and optical behavior of epoxy–TEOS/MWCNTs composites for solar cell covering
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