Preferred Language
Articles
/
ijl-294
Influence of Fractional CO2 Laser Irradiation on Temperature Elevation and Bonding Strength of Resin Cement to the Zirconia Ceramic
...Show More Authors

Abstract: Objectives: To investigate the effect of temperature elevation on the bonding strength of resin cement to the zirconia ceramic using fractional CO2 laser. Background: Fractional CO2 laser is an effective surface treatment of zirconia ceramic, as it increases the bonding strength of zirconia to resin cement. Methods: Thirty sintered zirconia discs (10 mm diameter, 2 mm thickness) were prepared and divided to three groups (N=10) and five diffident pulse durations were used in each group (0.1, 0.5, 1, 5 and 10 ms). Group A was treated with 10 W power setting, group B with 20 W and group C with 30 W. During laser irradiation, temperature elevation measurement was recorded for each specimen. Luting cement was bonded to the treated zirconia surfaces and cured for 30 seconds. Shear bond strength was evaluated by a testing machine (universal) with bond failure mode determination. Results: The lowest temperature elevation measurement of the irradiated specimen which gave maximum shear bond strength was about 1.6±0.3 Ċ higher than ambient room temperature (27±0.2 ºC). Apparent micromechanical irregularities were seen in the treated samples and cracks formation with increased pulse duration and power setting were also observed. Conclusions: The temperature elevation is a vital factor in the surface roughness of zirconia ceramic with fractional CO2 laser irradiation and the lowest temperature elevation at best shear bond strength of zirconia ceramic to the resin cement is satisfied with the shorter pulse duration of 0.1 millisecond.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Fri Sep 04 2015
Journal Name
International Journal Of Academic Research In Progressive Education And Development
The Influence of Three Teaching Methods on Undergraduate Physics Students' Group Work Skill
...Show More Authors

The purpose of this study is to compare the influence of three teaching methods, as represented by problem-based learning (PBL), the PBL with lecture method, and the conventional teaching on undergraduate physics students' group work skills among bachelor’s degree physics students. In this study, the pre- and post-test were done and the instruments were administered to the students for data collection. The actual sample size comprises of 122 students, who were selected randomly from the physics department, college of education in iraq. Overall, the statistical results rejected null hypothesis of this study. Thus, using the PBL without or with lecture method enhances the skills of the group work among the bachelor’s degree physics studen

... Show More
Publication Date
Fri Feb 01 2019
Journal Name
Journal Of Physics: Conference Series
Study the effect of gamma Irradiation on the Superconducting Properties of HgBaSrCa<sub>2</sub>Cu<sub>3</sub>O<sub>8+δ</sub>
...Show More Authors

View Publication
Scopus (3)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Sat Dec 04 2021
Journal Name
Transportation Research Record: Journal Of The Transportation Research Board
Gradation Effects on Strength and Deformation Properties of High-Quality Crushed Rock Base Materials
...Show More Authors

The importance of specifying proper aggregate grading for achieving satisfactory performance in pavement applications has long been recognized. To improve the specifications for superior performance, there is a need to understand how differences in aggregate gradations within the acceptable limits may affect unbound aggregate base behavior. The effects of gradation on strength, modulus, and deformation characteristics of high-quality crushed rock base materials are described here. Two crushed rock types commonly used in constructing heavy-duty granular base layers in the State of Victoria, Australia, with three different gradations each were used in this study. The gradations used represent the lower, medium, and upper gradation li

... Show More
View Publication
Scopus (4)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Sun Dec 30 2012
Journal Name
Al-kindy College Medical Journal
Age Influence on Knee Joint Flexors
...Show More Authors

Background : Knee flexors tightness has been documented in apparently healthy adults and in those with musculoskeletal problems, but the influence of age on the tightness has not been studied in Iraq. This study was therefore designed to determine the influence of age on knee flexors tightness in apparently healthy subjects.Methods: Knee flexors tightness was measured using the active knee extension test (AKET) in 200 apparently healthy male and female subjects, aged 13 to 59 years. The subjects were recruited into 5 age groups using the purposive sampling technique.Knee flexors tightness was compared across the age groups using one-way analysis ofvariance (ANOVA). The independent t-test was used to compare knee flexors tightness on both

... Show More
View Publication Preview PDF
Publication Date
Sun Oct 01 2017
Journal Name
مجلة القادسية للعلوم الرياضية
The impact of leverage in two different environments on the development of weapons and arms explosion strength on some physiological indicators and the accuracy of the performance of the service and crushing volleyball skills
...Show More Authors

ھدف البحث الـــــى : ١ -إعداد تدریبات القوة الارتدادیة في وسطین متباینین على بعض المؤشرات الفسیولوجیة لتطویر القوة الانفجاریة ودقة مھارتي الأرسال والضرب الساحق بالكرة الطائرة . ٢ -التعرف على تأثیر تدریبات القوة الارتدادیة في وسطین متباینین على بعض المؤشرات الفسیولوجیة لتطویر القوة الانفجاریة.. ٣ -التعرف على تأثیر تدریبات القوة الارتدادیة في وسطین متباینین على دقة مھارتي الأرسال والضرب الساحق بالكرة الطائرة

... Show More
Publication Date
Thu May 31 2012
Journal Name
Al-khwarizmi Engineering Journal
Effect of Journal Misalignment on the Static Characteristics of Porous Journal Bearings Lubricated with Couple Stress Fluid
...Show More Authors

In this paper, a theoretical study to the effect of journal misalignment on the static characteristics of oil filled porous journal bearing when lubricated with couple stress fluid has been carried out.

The analytical model used through this work is for a bearing with isotropic permeability. Considering isotropic permeability the Reynolds' equation for the oil film is modified to include a so – called filter term and the effect of fluid coupled stress. The pressure equation for the porous medium is obtained from Darcy's law and continuity equation. The equation which was used to evaluate the oil film thickness was modified to include the effect of possible misalignment in longitudinal and transverse directions. The governing eq

... Show More
View Publication Preview PDF
Publication Date
Sun Jan 01 2017
Journal Name
Journal Of Petroleum Science And Engineering
Nanoparticles influence on wetting behaviour of fractured limestone formation
...Show More Authors

Nanoparticles have gained considerable interest in recent times for oil recovery purposes owing to significant capabilities in wettability alteration of reservoir rocks. Wettability is a key factor controlling displacement efficiency and ultimate recovery of oil. The present study investigates the influence of zirconium (IV) oxide (ZrO2) and nickel (II) oxide (NiO) nanoparticles on the wetting preference of fractured (oil-wet) limestone formations. Wettability was assessed through SEM, AFM and contact angle. The potentials of the nanoparticles to alter oil-wet calcite substrates water wet, was experimentally tested at low nanoparticle concentrations (0.004–0.05 wt%). Quite similar behaviour was observed for both nanoparticles at the same

... Show More
Scopus (92)
Crossref (83)
Scopus Clarivate Crossref
Publication Date
Sat Jul 01 2017
Journal Name
Al–bahith Al–a'alami
The impact of new media in social relations: (A field study on a sample of young people in Baghdad)
...Show More Authors

Modern communication and media technology has pioneered new horizons and curried out deep changes in the various fields of social life, It effected enormously human communication as well.
Content one Who late the developments which have effected the social relations ،due to the new media ،especially Face book ,will certainly notice the far cry changes of the social relation net which has been effected ,in a way or another ،the accelerated development ،under the appearance of the so called the virtual society .
Face book has embodied the means – communication ,which has become an important turn point in the social communication .
It is the point the present paper tries to expose an discuss by a field study curried on a sam

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sat Oct 01 2022
Journal Name
Baghdad Science Journal
Effect of Alstonia Boonei Stem Bark Extracts on the Activity of Liver Maker Enzymes in Rats Induced by Ccl4
...Show More Authors

This study investigated the outcome of Alstonia boonei stem bark on liver enzymes after inducing the Wistar albino rats with carbon tetrachloride (CCl4). This effect of plant extract was compared with silymarin – a drug commonly used for the treatment of chronic hepatocyte disorder. The plant sample was extracted with ethanol; acute toxicity study of the extract was performed on eighteen Wistar mice, while 30 rats were sacrificed for liver enzymes assay. The rats were divided into six clusters: each cluster has five rats, culster 1 served as control and was given 2 mL/kg b.w - distilled water; clusters 2 – 6 were CCl4 induced. Cluster 2 was untreated but served as the negative control while cluster 3 wa

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Clarivate Crossref
Publication Date
Sun Mar 30 2025
Journal Name
مجلة المستنصرية للدراسات العربية والدولية
أثر العمالة الاجنبية في ارتفاع مستويات البطالة في العراق
...Show More Authors

ساهم توافد العمالة الأجنبية في تفاقم مشكلة البطالة في العراق الذي يستقبل المئات منهم سنوياً، في ظل تخرج آلاف الطلاب من الجامعات العراقية وانطلاقهم إلى سوق العمل بالتزامن مع عدم تنشيط دور القطاع الخاص بسبب التجاذبات السياسية والأوضاع الاقتصادية والأمنية التي أثرت بشكل كبير في تفعيله وجذب المستثمرين، وعلى رغم ذلك استمر توافد العمالة الأجنبية التي وجدت في العراق عبارة عن فرص ثمينة لا سيما في قطاع الخدمات، مما

... Show More
View Publication Preview PDF