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Evaluation of shear bond strength of zirconia to tooth structure after different zirconia surface treatment techniques
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Background: This study aimed to evaluate the effect of zirconia different surface treatments (primer, sandblast with 50μmAl2O3, Er,Cr:YSGG laser) on shear bond strength between zirconia surface and resin cement. Material and methods: Sixty presintered Y-TZP zirconia cylinder specimens (IPS e.max ZirCAD, Ivoclar vivadent) will be fabricated and sintered in high temperature furnace of (1500 C for 8 hours) according to manufacturer’s instructions to the selected size and shape of (5mm. in diameter and 6mm in height). All specimens were ground flat using 600.800.1000.1200, aluminum oxide abrasive paper to obtain a standardized surface roughness. Surface roughness values were then recorded in µm using surface roughness tester (profilometer) to obtain a standardized data base line for all samples. The specimens were then randomly divided into three main groups (n=20); group A: no surface treatment (control group), group B: specimens in this group treated with 50μm Al2O3 and group C: specimens in this group treated with Er,Cr:YSGG laser. Sixty sound human premolars were used in this study, after construction of acrylic blocks, the occlusal surface of the teeth were ground flat, with diamond cutting disk to obtain a flat dentine surface . Prior to cementation of zirconia cylinders to tooth specimens subgroups (A1,B1,C1) will receive a coat of metal/zirconia primer and left to react for three minutes, while the subgroups (A2,B2,C2) were left undisturbed. Bonding surface of zirconia cylinder was then luted with SpeedCEM self adhesive resin cement under a static load of 2Kg. placed on the vertical arm of the surveyor and allowed to auto cure for 4minutes.The final cemented specimens were then stored in distilled water at room temperature for 24hours. All specimens were subjected to shear loading force in a universal testing machine at crosshead speed of 1mm/min. The shear bond strength values were analyzed statistically with one-way ANOVA; the fractured surfaces of zirconia cylinders were examined with a stereo-microscope to observe the failure mode. Results: The air borne-particle of 50μm followed by primer application showed significantly the higher bond strength than other groups. Conclusion : Within the limitation of this study, the results showed that sandblasting the bonding surface of zirconium cylinders with 50μmAl2O3 produced the highest values of shear bond strength , also the use of primer enhanced shear bond strength as well. Keyword: zirconia surface treatments, shear bond strength.

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Publication Date
Sat Feb 01 2025
Journal Name
Journal Of The College Of Basic Education
Rationing two test in strength endurance for young under the age of 16
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Publication Date
Tue Jan 19 2021
Journal Name
Sn Applied Sciences
Post-fire serviceability and residual strength of composite post-tensioned concrete T-beams
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Abstract<p>In this study, the response of ten composite post-tensioned concrete beams topped by a reinforced concrete deck with adequate reinforcing shear connectors is investigated. Depending on the concrete compressive strength of the deck slab (20, 30, and 40 MPa), beams are grouped into three categories. Seven of these beams are exposed to a fire attack of 700 and 800 °C temperature simultaneously with or without the presence of a uniformly distributed sustained static loading. After cooling back to ambient temperature, these composite beams are loaded up to failure, using a force control module, by monotonic static loading in a four-point-bending setup with two symmetrical concentrated loads applied in </p> ... Show More
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Publication Date
Fri Jan 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Estimation of a Parallel Stress-strength Model Based on the Inverse Kumaraswamy Distribution
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 The reliability of the stress-strength model attracted many statisticians for several years owing to its applicability in different and diverse parts such as engineering, quality control, and economics. In this paper, the system reliability estimation in the stress-strength model containing Kth parallel components will be offered by four types of shrinkage methods: constant Shrinkage Estimation Method, Shrinkage Function Estimator, Modified Thompson Type Shrinkage Estimator, Squared Shrinkage Estimator. The Monte Carlo simulation study is compared among proposed estimators using the mean squared error. The result analyses of the shrinkage estimation methods showed that the shrinkage functions estimator was the best since

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Publication Date
Wed May 29 2019
Journal Name
Journal Of Planner And Development
War disasters and their effects on urban structure
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Many urban and rural areas fall under the impact of disasters, whether natural or industrial, and with increasing complexity in urban areas, with diversity of economic, social and political components, and technological and cognitive development, the effects of disasters and wars have increased with the time, where disasters are affecting all aspects of life, causing great waste of property and lives, also displacement of populations and disruption of economic life, these effects are multiplied if they are not dealt with in sound curricula and scientific strategies.

The research aims to identify the experiences of some countries and their strategies and effective programs in reconstruction after exposure to disasters and wars wit

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
â- structure properties ofZn-Phthalocyanine organic semi-conductor
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The x-ray fluorescence (XRF) of Znpc molecule with (flow of Ar) and Znpc molecule with (grow in N2) showed two peaks at (8.5and 9.5 Kv) referring to orbital transition ) K?-shell & K?-shell) respectively. The study of x-ray diffraction (XRD) where it was observed good growth of the crystal structure as a needle by the sublimation technique with a ?-phase of (monoclinic structure ) . Using Bragg equation the value of the interdistance of the crystalline plane (d-value) were calculated. We noticed good similarity with like once in the American Standards for Testing Material (ASTM) .Powder Diffraction File (PDF) Program was used to ensure the information obtained from (ASTM) . The output of (PDF) was compared with celn program, where the val

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Publication Date
Wed Sep 15 2021
Journal Name
Al-academy
The plastic structure in the lyrical introduction to pre-Islamic poetry " The hanging Tarfa bin Al-Abd as a model": زينب خليل حسين
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The research deals with the lyrical introduction in the commentary of Tarfa bin al-Abd as a formative system characterized by flexibility and richness of imagination, which achieved a formative treatment and a unique construction within the structures of the structural and semantic language. I dealt with the poetic verses represented by the lyrical introduction as a formative hypothesis, basing its goal on a methodological framework distributed on the problem that was summarized by the following question: Is it possible to look at the poetic pattern within the pre-Islamic poem / hanging blinking as a model, in its plastic dimensions and to identify the stylistic treatment that achieves the formation space within the poetic text. The rese

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Publication Date
Tue Dec 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Comparison between Electroplating and Electroless on Plastic Surface
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We report a method of converting non-conductive plastic surfaces into conductive by plating either copper electroless or copper electroplating -carbon black containing bending Agent onto Perspex plastics . Various approaches have been studied in order to comparing properties of the plated copper for two methods such as scanning electron microscopy (SEM),thickness, roughness, porosity, tensile Strength and elongation. The results show that the surface of electroplating was uniform, compact, and continuous and it had an obvious metallic sheen, while the surface of plated copper for electroless for it had many pores. Also observed that the coating was composed of small cells. Thes

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Publication Date
Sat Nov 28 2020
Journal Name
Iraqi Journal Of Science
The Expression of Different Micrornas in Iraqi Patients with Childhood Acute Leukemia and Their Association to C/EBP-Î’ Serum Level
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Leukemia is the most common cancer in children which causes death despite the high survival rate. Therefore,  new methods are required to find a suitable therapy. A small RNA called microRNAs (miRNAs) is used as a biomarker for cancer diagnosis and early prognostic evaluation. Expression levels of three miRNAs from the 3' arm (miR-142-3p, miR-223-3p and miR-146-3p) were detected in serum samples from 30 acute leukemic children and from 30 healthy individuals by using qPCR. The miR-142-3p and miR-146-3p profiles were significantly downregulated (P=0.0010 and 0.0012, respectively), while miR-223 was found to be significantly upregulated (P= 0.0044) in the pateints. Serum level of C/EBP-β

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Publication Date
Mon Dec 03 2018
Journal Name
The Iraqi Postgraduate Medical Journal
Operative Treatment by Plate and Screws Versus Conservative Treatment of Closed Displaced Fracture of the Mid Third of Clavicle in Adults: Comparative Study
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BACKGROUND: Clavicle fractures are common injuries in young active individuals, the mid third of the clavicle is most commonly fractured part(80% of clavicle fracture) OBJECTIVE: To compare the outcomes of operative and non operative management of displaced and or comminuted closed fracture of the mid third of clavicle in young adults PATIENTS AND METHODS: This prospective observational study of 24 patients of fracture of the mid third of the clavicle was conducted in Alkindy teaching hospital from July 2015 to January 2017 and divided into two groups; one managed by operative treatment with plate and screws and the other by non operative sling immobilization after taking the consent and the patients were seen at 2, 4, 6 weeks,3, 6, and 9 m

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Publication Date
Sun Dec 29 2019
Journal Name
Iraqi Journal Of Science
Calculating the variations of sunrise, sunset and day length times for Baghdad city.With comparison to different regions of the world in year 2019
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     The sunrise, sunset, and day length times for Baghdad (Latitude =33.34º N, Longitude =44.43º E) were calculated with high accuracy on a daily basis during 2019. The results showed that the earliest time of sunrise in Baghdad was at 4h: 53m from 5 Jun. to 20 Jun while the latest was at 7h: 07m from 5 Jan. to 11 Jan. The earliest time of sunset in Baghdad was at16 h: 55m from 30 Nov. to 10 Dec. whereas the latest was at 19h: 16m from 25 Jun. to 5 Jul. The minimum period of day length in Baghdad was 9h: 57m) in 17 Dec. whereas the maximum period was 14h: 22m) in 20 Jun. Day length

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