Preferred Language
Articles
/
jbcd-2893
The impact of various staining substances and immersion time on the stainability of bonded sapphire brackets with three kinds of light cure orthodontic adhesives (An in-vitro study)
...Show More Authors

Background: The need of the patient for a more reasonable esthetic orthodontic intervention has risen nowadays. Thus, orthodontists make use of esthetic orthodontic materials like brackets, ligature elastics, and arch wires. The esthetic brackets come as different forms of materials, such as ceramic brackets, which have their stainability remaining as the most important consideration for the patients and the orthodontists. This study aimed to compare the staining effects of various staining materials, including black tea, cigarette smoke and Pepsi, as well as the time effect on the color stability of sapphire ceramic brackets bonded with three kinds of light cure orthodontic adhesives: Transbond, Resilience and Enlight. Materials and Methods: Three hundred sixty sapphire brackets were utilized and divided into three different groups (120 brackets per group) based on the type of bonding material. Each group was further subdivided into four subgroups (30 brackets each) based on the media in which the brackets were fully immersed, including distilled water, black tea, cigarette smoke and Pepsi. Moreover, each of these subgroups were further subdivided, based on the time of immersion relative to each media, into 3 different smaller subgroups (10 brackets each): one day, 7 days and 14 days with incubation at 37°C. A UV-visible type of spectrophotometer was utilized in order to perform a light absorption test. ANOVA and post hoc LSD tests were used for comparison. Results: The smoke of cigarette appeared to be the highest potent staining type among the tested materials followed by Pepsi and tea. The staining effects of all kinds of staining materials in relation to the bonded brackets color with all adhesive types were raised with increased time of immersion. Conclusion: The patient’s cooperation and habits should be taken into consideration when using sapphire orthodontic brackets. In addition, the patients should be instructed to decrease the consumption of staining beverages. Keywords: Stainability, staining materials, sapphire brackets.

 

 

Scopus Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Jan 25 2018
Journal Name
International Journal Of Current Engineering And Technology
Model-Based Design of Piezoelectric Patches used to Repair Damaged Beams under Static Load
...Show More Authors

Static loads exposing to mechanical components can cause cracks, which are lead to form stress concentration regions causing the failure of structure. Generally, from 80% to 90% of structure failure is due to initiation of the cracks. Therefore, it is necessary to repair the crack and reduce its effect on the structure where the effect of the crack is modelled as an additional flexibility to the structure. In the last few years, piezoelectric materials have been considered as one of the most favourable repairing techniques. The piezoelectric material converts the applied voltage on it to a bending moment to counter the bending moment caused by the external load on the beam at the crack location. In this study, the design of the piez

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Mar 01 2019
Journal Name
Al-khwarizmi Engineering Journal
Thermo Elasto-Plastic Analysis of Rotating Axisymmetrical Bodies Using Modified Von-Mises Yield Criterion
...Show More Authors

In the present work, the behavior of thick-walled cylinder of elasto-plastic material (polymeric material) has been studied analytically. The study is based on modified Von-Mises yield criterion (for non metallic material). The equations of stress distribution are obtained for the cylinder under general cases of elastic expansion, plastic initiation and elastic-plastic expansion.

        A computer program is developed for evaluating the stress distribution. The solution is carried out for worst boundary conditions when the cylinder is subjected to the combination of pressure load, inertia load, and temperature gradient.

        The results are presente

... Show More
View Publication Preview PDF
Publication Date
Mon Sep 01 2014
Journal Name
Al-khwarizmi Engineering Journal
Experimental Performance of a Finned-tube Silica Gel Adsorption Chiller for Air-Conditioning Application
...Show More Authors

This work presents the construction of a test apparatus for air-conditioning application that is flexible in changing a scaled down adsorbent bed modules. To improve the heat and mass transfer performance of the adsorbent bed, a finned-tube of the adsorbent bed heat exchanger was used. The results show that the specific cooling power (SCP) and the coefficient of performance (COP) are 163 W/kg and 0.16, respectively, when the cycle time is 40 min, the hot water temperature is 90oC, the cooling water temperature is 30oC and the evaporative water temperature is 11.4oC.

View Publication Preview PDF
Publication Date
Sun Mar 30 2003
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Improvement of CIATIM-201 Grease Properties for Use under Severe Conditions using Suitable Additives
...Show More Authors

View Publication Preview PDF
Publication Date
Sun Jun 20 2021
Journal Name
Baghdad Science Journal
Noor's Curve, a New Geometric Form of Agnesi Witch, a Construction Method is Produced
...Show More Authors

In this paper, a new form of 2D-plane curves is produced and graphically studied. The name of my daughter "Noor" has been given to this curve; therefore, Noor term describes this curve whenever it is used in this paper. This curve is a form of these opened curves as it extends in the infinity along both sides from the origin point. The curve is designed by a circle/ ellipse which are drawing curvatures that tangent at the origin point, where its circumference is passed through the (0,2a). By sharing two vertical lined points of both the circle diameter and the major axis of the ellipse, the parametric equation is derived. In this paper, a set of various cases of Noor curve are graphically studied by two curvature cases;

... Show More
View Publication Preview PDF
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Sun Sep 24 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Approximate Solution for Fuzzy Differential Algebraic Equations of Fractional Order Using Adomian Decomposition Method
...Show More Authors

      In this paper we shall prepare an  sacrificial solution for fuzzy differential algebraic equations of fractional order (FFDAEs) based on the Adomian decomposition method (ADM) which is proposed to solve (FFDAEs) . The blurriness will appear in the boundary conditions, to be fuzzy numbers. The solution of the proposed pattern of  equations is studied in the form of a convergent series with readily computable components. Several examples are resolved as  clarifications, the numerical outcomes are obvious that the followed approach is simple to perform and precise when utilized to (FFDAEs).

View Publication Preview PDF
Publication Date
Sun Mar 17 2019
Journal Name
Baghdad Science Journal
Enhancement of Hydrothermally Co3O4 Thin Films as H2S Gas Sensor by Loading Yttrium Element
...Show More Authors

The gas sensing properties of Co3O4 and Co3O4:Y nano structures were investigated. The films were synthesized using the hydrothermal method on a seeded layer. The XRD, SEM analysis and gas sensing properties were investigated for Co3O4 and Co3O4:Y thin films. XRD analysis shows that all films are polycrystalline in nature, having a cubic structure, and the crystallite size is (11.7)nm for cobalt oxide and (9.3)nm for the Co3O4:10%Y. The SEM analysis of thin films obviously indicates that Co3O4 possesses a nanosphere-like structure and a flower-like structure for Co3O4:Y.

The sen

... Show More
View Publication Preview PDF
Scopus (4)
Scopus Clarivate Crossref
Publication Date
Wed Jan 01 2014
Journal Name
Journal Of The College Of Languages (jcl)
بزووتنةوةى (روانـــــطة) قؤناغيَكى نويَي شيعرى كوردى Rwanga Movement: a New Stage of Kurdish Poetry
...Show More Authors

Rwanga (view) movement is a new Kurdish poetry movement. Some poets and modern storywriters published a manifest in 1970. They have made a group of changes in the content and appearance of Kurdish poetry. They were under the influence of western literature schools such as Surrealism, Dadaism and Existentialism. Likewise, the impact of the new Arabic literature that appeared by the end of 1960s on them was obvious as they were imitating such literatures. Nevertheless, the condition of Kurdistan at that time was in need of a new literature to express that new stage. Sherko Bekas was one of those poets who became the dynamo of the poetic movement in which the rebellion spirit was embodied in the modern way of dealing with culture, rhyme, rh

... Show More
View Publication Preview PDF
Publication Date
Wed Dec 29 2021
Journal Name
Al-khwarizmi Engineering Journal
Analysis of Magnetorheological Normally Close Directional Control Valve: Magnetorheological normally close directional control valve
...Show More Authors

This valve is intended for use in valves for steering movement, using the qualities of the Magneto-rheological (MR) fluid to regulate the fluid, direct contact without the utilization of moving parts like a spool, a connection between electric flux, and fluid power was made, The simulation was done to employ the" finite element method of magnetism (FEMM)" to arrive at the best design. This software is used for magnetic resonance valve finite element analysis. The valve's best performance was obtained by using a closed directional control valve in the normal state normally closed (NC) MR valve, with simulation results revealing the optimum magnetic flux density in the absence of a current and the shedding condition, as well as the optimum

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Crossref
Publication Date
Fri Jul 21 2023
Journal Name
Journal Of Engineering
SIMULATION OF OPTIMAL SPEED CONTROL FOR A DC MOTOR USING LINEAR QUADRATIC REGULATOR (LQR)
...Show More Authors


This paper describes DC motor speed control based on optimal Linear Quadratic Regulator (LQR) technique. Controller's objective is to maintain the speed of rotation of the motor shaft with a particular step response.The controller is modeled in MATLAB environment, the simulation results show that the proposed controller gives better performance and less settling time when compared with the traditional PID controller.

View Publication Preview PDF
Crossref (4)
Crossref