Preferred Language
Articles
/
jbcd-193
Radiopacity of modified microhybrid composite resin:(An in vitro study)
...Show More Authors

Background: The aim of this study was to measure the radiopacity (RO) of modified microhybrid composite resins by adding 2 types of nanofillers (Zinc Oxide and Calcium Carbonate) in two concentrations 3% and 5% and comparing them to unmodified microhybrid composite resins and to nanofilled composite resin. Materials and Methods: Two types of composite resin were used (Microhybrid composite MH Quadrent anterior shine and Nanofilled composite resin Filtek Z350 XT), for each tested group five disk-shaped specimens (1-mm-thick and 15 mm diameter) were fabricated. The material samples were radiographed together with the aluminum step wedge. The density of the specimens was determined with a transmission densitometer and was expressed in term of equivalent thickness of aluminum. Data analyzed by one-way ANOVA. Results: The radiopacity (RO) values of the tested group ranged between (0.9293- 2.6242 Eq. Al thickness) and there were significant differences among them. Nanofilled composite resin Filtek Z350 XT showed the highest value of RO while unmodified Microhybrid composite MH Quadrent anterior shine showed the lowest value of RO. Conclusion: The addition of 3% of both the ZnO and CaCO3 nanofillers fillers to microhybrid composite significantly increased the RO, while the addition of 5% of CaCO3 and ZnO nanofillers to microhybrid composite showed non-significant increase in the RO of the composite.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Aug 15 2023
Journal Name
Journal Of Economics And Administrative Sciences
Inclusive leadership in the General Secretariat for the Council of Ministers - An analytical research
...Show More Authors

The current research aims to evaluate the level of inclusive leadership within the General Secretariat for the Council of Ministers, and its role in achieving integration in work through the need to improve relationships between different administrative levels, facilitate participation, expression of opinions, and belonging to the organization. In order to achieve the research objective, the descriptive analytical statistical method was chosen using the SPSS V.25 programs, with various statistical methods and measures, including mean, standard deviation, variance coefficient, relative importance, and simple regression, through a questionnaire tool for data collection. The research community included the leadership in the sample of resear

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Jun 10 2009
Journal Name
Iraqi Journal Of Laser
The performance of a passively Q-switched Cr:YAG4+ in an end- pumped laser system
...Show More Authors

A characteristic study of a passively Q-switched diode pumped solid state laser system is presented in this work. For laser a comparison study for the theoretically calculated results with a simulation results using a software which calculates the Q-switched solid state laser parameters was such as energy, peak power and pulse width were performed. There was a good agreement between our theoretical calculations and the simulation values.

View Publication Preview PDF
Publication Date
Thu May 18 2023
Journal Name
Journal Of Engineering
Evaluation of Convective Heat Transfer and Natural Circulation in an Evacuated Tube Solar Collector
...Show More Authors

The evacuated tube solar collector ETC is studied intensively and extensively by experimental and
theoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climate
from April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collector
consists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relation
between convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect of
tube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.e
closed and open flow) to evaluate the heat loss coefficient

... Show More
View Publication Preview PDF
Crossref (17)
Crossref
Publication Date
Fri Sep 06 2024
Journal Name
Brazilian Journal Of Physics
Effect of the Fear Factor and Prey Refuge in an Asymmetric Predator–Prey Model
...Show More Authors

This study investigates the influence of fear, refuge, and migration in a predator–prey model, where the interactions between the species follow an asymmetric function response. In contrast to some other findings, we propose that prey develop an anti-predator response in response to a concentration of predators, which in turn increases the fear factor of the predators. The conditions under which all ecologically meaningful equilibrium points exist are discussed in detail. The local and global dynamics of the model are determined at all equilibrium points. The model admits several interesting results by changing the rate of fear of predators and predator aggregate sensitivity. Numerical simulations have been performed to verify our theoret

... Show More
View Publication
Scopus (12)
Crossref (7)
Scopus Clarivate Crossref
Publication Date
Mon Sep 14 2015
Journal Name
Spe North Africa Technical Conference And Exhibition
Feasibility of Gas Lift to Increase Oil Production in an Iraqi Giant Oil Field
...Show More Authors
Abstract<p>Gas lift is one of the artificial lift techniques which it is frequently implemented to raise oil production. Conventionally, the oil wells produce depending on the energy of reservoir pressure and solution gas which declines due to continuous production. Therefore, many oil wells after a certain production time become unable to lift oil to the surface. Thus, the continuity of production requires implementation of gas lift which works to decrease the average fluid density in the tubing by injection gas through the annulus into the tubing. This paper aims to get maximum oil production of an Iraqi giant oil field at optimum injected gas rate. The field is located in south of Iraq and in</p> ... Show More
Scopus (9)
Crossref (6)
Scopus Crossref
Publication Date
Sat Apr 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Use aggregate slide estimate additive splines estimation for the diagnosis of non-linear composite model self-regression with practical application
...Show More Authors

Nonlinear time series analysis is one of the most complex problems ; especially the nonlinear autoregressive with exogenous variable (NARX) .Then ; the problem of model identification and the correct orders determination considered the most important problem in the analysis of time series . In this paper , we proposed splines  estimation method for model identification , then we used three criterions for the correct orders determination. Where ; proposed method used to estimate the additive splines for model identification , And the rank determination depends on the additive property  to avoid the problem of curse dimensionally . The proposed method is one of the nonparametric methods , and the simulation results give a

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Nov 01 2021
Journal Name
Journal Of Physics: Conference Series
Neural Network Model for Synthesis of Thermally Sprayed (AI/AI<sub>2</sub>O<sub>3</sub>) Composite Protective Coatings
...Show More Authors
Abstract<p>Al<sub>2</sub>O<sub>3</sub> and Al<sub>2</sub>O<sub>3</sub>–Al composite coatings were deposited on steel specimens using Oxy-acetylene gas thermal spray gun. Alumina was mixed with Aluminum in six groups of concentrations (0, 5, 10,12,15 and 20% ) Al2O3, Specimens were tested for corrosion using Potentiodynamic polarization technique. Further tests were conducted for the effect of temperature on polarization curve and the hardness tests for the coated specimens. At first, Modelling was carried out using MINITAB-19, least square method, as a 2nd degree nonlinear model, bad results were achieved because of the high nonlinearity. Better result w</p> ... Show More
View Publication
Scopus Crossref
Publication Date
Mon Feb 24 2025
Journal Name
Advances In Structural Engineering
Experimental and numerical investigation on the behavior of composite reinforced concrete columns encased by steel section and hybrid GFRP section
...Show More Authors

GFRP was employed in constructions as an alternative to steel, which has many advantages like lightweight, large tensile strength and resist corrosion. Existing researches are insufficient in studying the influence of hybrid reinforced concrete composite columns encased by GFRP I-section (RCCCEG) and I-section steel (RCCCES). In this study twenty one (RC) specimens of a cross-section of 130 mm × 160 mm, with different length (long 1600 mm and short 750 mm) were encased by using I-section (steel and GFRP) and tested under various loading (concentric, eccentric and flexural loads). The test was focused on the influence of many parameters; load-carrying capacity, mode of failure, deformation and drawing an interaction diagram (N-

... Show More
View Publication
Scopus (6)
Crossref (6)
Scopus Clarivate Crossref
Publication Date
Sun Sep 04 2016
Journal Name
Baghdad Science Journal
Degradation of Brilliant Green by Using a bentonite Clay- Based Fe Nano Composite Film as a Heterogeneous Photo- Fenton Catalyst.
...Show More Authors

This paper aims to study the chemical degradation of Brilliant Green in water via photo-Fenton (H2O2/Fe2+/UV) and Fenton (H2O2/Fe2+) reaction. Fe- B nano particles are applied as incrustation in the inner wall surface of reactor. The data form X- Ray diffraction (XRD) analysis that Fe- B nanocomposite catalyst consist mainly of SiO2 (quartz) and Fe2O3 (hematite) crystallites. B.G dye degradation is estimated to discover the catalytic action of Fe- B synthesized surface in the presence of UVC light and hydrogen peroxide. B.G dye solution with 10 ppm primary concentration is reduced by 99.9% under the later parameter 2ml H2O2, pH= 7, temperature =25°C within 10 min. It is clear that pH of the solution affects the photo- catalytic degradation

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Mar 15 2022
Journal Name
Journal Of Baghdad College Of Dentistry
Natural preparation of rice husk-derived silica and eggshell-derived calcium carbonate composite as a coating material for dental implant
...Show More Authors

Background: The world is in front of two emerging problems being scarceness of virgin re-sources for bioactive materials and the gathering of waste production. Employment of the surplus waste in the mainstream production can resolve these problems. The current study aimed to prepare and characterize a natural composite CaO-SiO2 based bioactive material derived from naturally sustained raw materials. Then deposit this innovative novel bioactive coating composite materials overlying Yttria-stabilized tetragonal zirconia substrate. Mate-rials and method; Hen eggshell-derived calcium carbonate and rice husk-derived silica were extracted from natural resources to prepare the composite coating material. The manufac-tured powder was characterized

... Show More
View Publication Preview PDF
Scopus (10)
Crossref (10)
Scopus Crossref