Preferred Language
Articles
/
nRcsno0BVTCNdQwCxBbn
The effect of composite bonding spot size and location on the performance of poly-ether-ether-ketone (PEEK) retainer wires
...Show More Authors

Background: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center of the crown, closer to the lateral incisor. The linear displacement of the teeth, strains of the periodontal ligament, and stresses in PEEK wire and composite were evaluated. The data was numerically produced with color coded display by the software. Selected values were tabulated and compared among models. Results: The amount of linear displacement and strain was very low. Stresses in the wire and composite were affected by the size and position of the composite bonding spot. The safe limits were identified at 235 MPa for PEEK and 100 MPa for composite. The basic model had a von Mises stress in the PEEK wire of 122.09 MPa, and a maximum principal stress in the composite of 99.779 MPa. Both stresses were within the safe limits, which means a lower risk of failure in PEEK and composite. All other models had stresses that exceeded the safe limit of the composite. The 3 mm composite model was the only one that developed stresses in the wire more than the safe limits of PEEK. Conclusions: Within the limitations of this study, bonding PEEK wires with 4 mm bonding spots to the clinical crown center provided the best mechanical performance of the wires and spots; otherwise, the mechanical properties of the wire and composite would be affected and, therefore, might affect the retention process. Keywords: Retention, PEEK, Finite element analysis

Scopus Crossref
Publication Date
Thu Apr 27 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Effect of Humidity on Superconducting Phase of Bi-2223
...Show More Authors

  The ceramics specimens as superconducting phase (Bi2PbxSr2Ca2Cu3O10+δ) with different concentrations of Pb from (0.0-0.5) were prepared by solid-state reaction method. Superconducting samples were exposed to high humidity (RH 75% at 25ºC) for seven weeks time interval. The humidity has a negative effect on the transition temperature of superconductor phase .It destroys the superconducting phase and the samples were converting to insulator.  
 

View Publication Preview PDF
Publication Date
Tue Dec 01 2015
Journal Name
Journal Of Engineering
Effect of Metakaolin on the geotechnical properties of Expansive Soil
...Show More Authors

Expansive soil spreads in Iraq and some countries of the world. But there are many problems can be occurred to the structures that built on, so we must study the characteristics of these soils due to the  problems that may be caused to these structures which built on these kinds of soil and then study the methods of treatment. The present study focuses on improving  the geotechnical properties of expansive soils by treating it Metakaolin(M). Metakaolin (M) has never been used before as an improvement material  for stabilizing the expansive soil . Metakaolin  is a pozzolanic material. It’s obtained by calcination of kaolinite clay at temperatures from 700°C to 800°C. Kaolin chemical composition is

... Show More
View Publication Preview PDF
Publication Date
Sun May 28 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Effect of Rifadin Drug on Lipids Metabolism of Rabbits
...Show More Authors

  The aim of this study was intended to study the effect of rifadin drug on lipids metabolism  in the blood of the rabbits .Eight rabbits were used in the experiment ,they were divided into two groups ,first group(control group ) was administrated with 15mg/ml /day normal saline for 35 days ,while the second group (treated group )was administrated with (15/mg /kg/day) for 35 days of rifadin( capsule 300mg/kg).This study examined the influences of rifadin drug on the concentration of cholesterol  , triglycerides , HDL ,LDL and  VLDL in rabbits sera .The result showed that there were no significant  increased (p>0.05) in cholesterol concentration in rifadin  treated group compared with control group ,and th

... Show More
View Publication Preview PDF
Publication Date
Wed Mar 01 2023
Journal Name
Journal Of Transportation Engineering
Effect of nanomaterials on the durability of hot mix asphalt
...Show More Authors

View Publication Preview PDF
Scopus (23)
Crossref (19)
Scopus Crossref
Publication Date
Sat Sep 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Effect of Flocculation on The ethanolic Production in Some Various Yeast
...Show More Authors

Ethanol production were evaluated by many strains with varing

degree of flocculation in fermentation medium of date extract withl 0

Brix, PHS in 30C0Ø¢  Ø¢ for Ø¢ 48hr.lt was found that ethanol production decrease with increase of flocculation degree and non-flocculant strain is Ø¢ more efficient in Ø¢ producing ethanol from flocculant strain,then

ethanol sensitivity were examined for the same strains, in liquid medium YE, it was found thatØ¢  Ø¢ strain is more sensitive from nonآ­ flocculant and ethanol sensitivity depends upon flocculation degree.

 

View Publication Preview PDF
Publication Date
Mon Oct 01 2018
Journal Name
Iraqi Journal Of Physics
SiO2 particles effect on the mechanical properties of the starch/PVA blends
...Show More Authors

The present work studies the mechanical properties of SiO2 μPs, and NPs in St/PVA blends. The samples were prepared by casting method as PVA, St/PVA blends at different concentrations (30, 40, 50, and 60 %). DSC and TGA tests were carried out to the samples evolved. The result showed a single glass transition temperature (Tg) for all St /PVA blends that was attributed to the good miscibility of the blends involved. It was found that (Tg) decrease with starch ratio increase. It was seen that (PVA) of (Tg=105 oC); The glass transition temperature which was decrease with starch ratio that was attributed to glass transition relaxation process due to micro-Brownian motion of the main chain back bond. The endothermic peak at 200 oC was attrib

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Mon Jul 07 2025
Journal Name
Al-fatih Journal
The impact of training on the sand development in the carrying(Speed ​​and power performance) BalambarzhEmpirical researchOn the young players Basra Balambarzh
...Show More Authors

تعد المبارزة أحد الألعاب الرياضية التي يتأثر فيها الأداء بتطور القدرات الخاصة بالأداء ومنها تحمل (سرعة وقوة الأداء ),وأن أكثر الأساليب السابقة في تدريب تطوير تحمل(سرعة وقوة الأداء) بالمبارزة تكون على ارض صلبة مثل الخشب والألمنيوم آو الإسفلت وفي بعض القاعات يكون التارتان, وظل هذا الأسلوب لفترات طويلة في العراق ،حيث تستخدم تدريبات الإثقال التي تعمل على تنمية تحمل القوة . أما في الوقت الحاضر فقد ظهر اتجاه حديث في

... Show More
View Publication
Publication Date
Sun May 02 2021
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of the auditor in allocating common costs in the gas industry and its reflection on the company's performance: Applied Research in North Gas Company
...Show More Authors

The auditor has a role in allocating joint costs in the gas industry, and the auditor's procedures are considered as systematic critical examination, analysis and evaluation of everything related to costs in general and joint costs in the gas industry in particular, with the aim of controlling the joint costs of gas industry products, and knowing the share of the cost of each product from the total industry costs Gas products reflect the reality of the company's performance by discovering weaknesses, defects and any errors, to ensure increased effectiveness and efficiency of the parties concerned with auditing them and imposing control and control over the company's resources, as well as

... Show More
View Publication Preview PDF
Publication Date
Fri Apr 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Empowerment administrative Factors and its impact on Performance of the service organization An analytic Research at the Ministry of Interior – General Directorate of Traffic
...Show More Authors

Abstract

The research study about the empowerment as an independent variable, in which details include (training and improvement, incentives, information sharing, trust, and delegation), has also focused on the performance of the service organization as a dependent variable in all dimensions which include (improve work efficiency, building the core competencies, focus on the beneficiary of the service, increasing the feeling of satisfaction of the employees, and the organizational support commitment). The research has been based on the opinions of a chosen sample of 75 service officers of the Ministry of Interior who work at the General Directorate of Traffic. The research problem has been identified by t

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Job satisfaction and its relation to the effectiveness of performance: Applied research on a sample of employees in the Federal board of supreme Audit
...Show More Authors

The research aimed to study the job satisfaction of the staff of the Federal board of supreme Audit and its relation to the effectiveness of their performance, The questionnaire was adopted as a main tool in the collection of data and information from a random sample of (54) employees of the Federal board of supreme Audit. In light of this, the data were collected and analyzed and the hypotheses were tested using the statistical program (SPSS).

The researchers reached a number of conclusions, the most important of which were: (1) the respondents' response to the variables of job satisfaction and the effectiveness of the performance were medium; (2) there was a significant relationship between job satisfaction and performance effe

... Show More
View Publication Preview PDF