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Influence of Fractional CO2 Laser Irradiation on Temperature Elevation and Bonding Strength of Resin Cement to the Zirconia Ceramic
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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.

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Publication Date
Sun Dec 05 2010
Journal Name
Iraqi Journal Of Laser
Comparative Histological Study of Dentinopulpal Responses in Class I Cavity Treated by Er: YAG Laser and Conventional Cavity Preparations: An in Vivo Trial
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The purpose of this study is to investigate the histopathological response of dentinopulpal
response of human teeth to the Er: YAG laser cavity preparation in comparison with the conventional
class I cavity preparation. Thirty five sound human upper and lower first premolar teeth which were
needed to be extracted for orthodontic purposes were used in the study. Regarding to the method of
cavity preparation, the teeth were grouped into three groups; Group1; Control group which consists of
seven sound teeth without cavity preparation, Group2; Conventional cavity preparation group and group
3; Er: YAG laser cavity preparation group. Each of Group2 and3 consists of fourteen teeth that is
subdivided into: A. 7teeth that e

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Publication Date
Thu Aug 01 2024
Journal Name
Misan Journal For Physical Education Sciences
A comparative study of the reasons for the reluctance of female physical education teachers in “Baqubah” to participate in refereeing sports competitions according to the variable of years of service
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When searching for an answer to the following question: What are the reasons for the reluctance of female physical education teachers in secondary schools to referee sports competitions according to the variable of years of service? It was found that the research aimed to reveal the differences between the opinions of the research sample of physical education teachers in secondary schools (girls) about refereeing sports competitions according to the variable of years of service. To achieve the research goal, it is assumed that there are significant differences between the average opinions of the research sample of female teachers and their reluctance and the reasons for the differences in the practice of refereeing sports competitions accor

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Publication Date
Sat Aug 01 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
Probability Concepts of Transfer Load to the Foundation of Container Structure
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This paper presents stochastic analysis using the perturbation method to model the structure of a container to verify the distributions of probability of maximum and minimum axial forces reactions in piles. The proposed simulation of a container port terminal under 11 scenarios of load combinations was presented. The probability distributions for live loads are assigned according to the input parameters of simulation data. Part of the load itself is implicitly combined such as vertical live load which includes the weight of equipment and containers and wind load. The structural model was simulated in the software STAAD Pro., while the statistical analyses were performed with MATLAB. The results demonstrated that, the most significant extern

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Publication Date
Wed Jan 01 2020
Journal Name
2nd International Conference On Materials Engineering & Science (iconmeas 2019)
New application of pervaporation to enhance the conversion of consecutive reaction
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This study investigates consecutive reaction assisted by pervaporation for the first time. It studies the saponification of diethyladipate DA with sodium hydroxide NaOH solution synchronous with separating ethanol from the reaction mixture through an aqueous – organic membrane. The effect of time on some variables such as: permeated ethanol concentration EtOH wt%, separation factor (α), concentration of NaOH solution CB in the reaction medium and the conversion of DA to monoethyladipate (the intermediate product) was studied. It was shown that EtOH wt% and the conversion increased with increasing time unlike CB but (α) showed the existence of maximum value during the time of experiment. The process of reaction assisted by pervaporation

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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
THE SIZES OF CITIES IN URBAN SYSTEM AND REGIONAL DEVELOPMENT -AN APPLIED RESEARCH OF KERBLA GOVERNORATE -
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There is a relationship between the sizes of urban centers and regional
development, concerning the role that these centers are playing in
developmental process.
The research assume that the urban system in the governorate, has
been affected by the external environment due to the religious dominance of
Kerbla city.
The research is composed of three sections, the first is a theoretical
background, which focus upon the general directions of the models and
theories that have a relationship with the subject. The second is a practical
part aims at determination the characteristics of the sizes of the cities in the
governorate. Depending upon of previous part, i.e., the practical part section three deals with

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Publication Date
Sat Dec 28 2024
Journal Name
Dental Hypotheses
Assessment of Color Change of Artificial White Spot Lesions after Sandblasting with Bioactive Glass, Resin Infiltration, or Microabrasion Followed by Color Stability Test by pH Cycling: An in Vitro Study
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Introduction: This study aimed to assess the color change of human teeth with artificial enamel white spot lesions (WSLs) after sandblasting with bioactive glass, resin infiltration, and microabrasion and to test color stability after pH cycling. Methods: Fifty extracted human mandibular first molars were randomly assigned into five groups: Sound, WSLs (untreated), and WSLs sandblasted with bioactive glass (Sylc), WSLs treated by resin infiltration (ICON), and WSLs treated by microabrasion (Opalustre), respectively. All specimens underwent a pH cycling procedure. The color parameters for each specimen were assessed using an Easyshade dental spectrophotometer at different time stages then the color changes (ΔE) were calculated. Results: The

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Publication Date
Mon Jun 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Experimental Determination of the Elastic and Viscous Behavior of Polycarbonate Melts at Different Temperatures and Their Relationship to the Steady State Viscosity via the Cox-Merz Rule
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Rheological instrument is one of the basic analytical measurements for diagnosing the properties of polymers fluids to be used in any industry. In this research polycarbonate was chosen because of its importance in many areas and possesses several distinct properties.
Two kinds of rheometers devices were used at different range of temperatures from 220 ˚C-300 ˚C to characterize the rheological technique of melted polycarbonate (Makrolon 2805) by a combination of different investigating techniques. We compared the results of the linear (oscillatory) method with the non-linear (steady-state) method; the former method provided the storage and the loss modulus of melted polycarbonate, and presented the Cox-Merz model as well. One of the

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Publication Date
Wed Jun 29 2022
Journal Name
Baltic Journal Of Law & Politics
The Geomorphological Aspects in Diyala Governorate and the Possibility of Investing Them for Tourism Activity According to the Perspective of Sustainable Development Using RS and GIS Techniques
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Diyala Governorate has many unique and diverse geomorphological features that the region enjoys, which are among the attractions for natural tourism, as the natural environment is considered a maker of tourism. The importance of geomorphological aspects as components of natural tourism is due to their association with tourism and entertainment, as a result of the enjoyment of many geomorphological aspects of the beauty of its natural landscape on the one hand, and on the other hand, the association of these manifestations with different types of tourism activity. Any tourist area as it is the main factor for tourist attractions, such as the presence of the Hamrin hills, and sand dunes. Planning for the development of tourism activity in the

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Publication Date
Sun Jan 01 2006
Journal Name
Diala Journal For Application Research
Study and calculation of the effects of excessive stress temperatures on the buoyant convection of clouds.
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Recent developments in two main phases of cumulus cloud studies are discussed; first the relations between the clouds and their energy sources in the subcloud layer and second, the interaction between the clouds and their environment in the cloud layer. Under the first heading, the various originating impulses for cumulus formation are mentionitd. and how the character of this impulse affects the spacing, scale and temperature structure of the clouds. The possible origins of trade cumuli are considered.

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Publication Date
Thu Mar 05 2026
Journal Name
Al–bahith Al–a'alami
Petra University’s Students’ Uses For SMS Messages and its Verifications (A Field Study on Students of Petra University’s Colleges)
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This study aims at identifying the extent of SMS usage and understanding the role it plays in satisfying users' needs and motivations. In order to achieve this aim, an analytical descriptive method was adopted by conducting a field survey among students at Petra University.

The study resulted in many conclusions, the most important of which is that using SMS meets the students' cognitive, social and communicational needs and desires, the highest being communicating with friends at 75%, followed by exchanging songs and videos at 52%, as well as exchanging photos at 45%. In regards to their motivation for using text messaging, forgetting daily problems scored highest at 81.4% and spending free time followed at 77.4%. This proves th

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