Introduction: This study was performed to compare the effect of Fractional CO2 laser or Q switched Nd:YAG laser of surface treatment on the shear bond strength of zirconia-porcelain interface. Methods: Fractional CO2 laser at 30 W, 2 ms, time interval 1 ms, distance between spots 0.3 mm, and number of scans is (4) or Q switched Nd:YAG laser at 30 J/mm2 and 10 Hz were used to assess the shear bond strength of zirconia to porcelain. Pre-sintered zirconia specimens were divided into three groups (n = 10) according to the surface treatment technique used: (a) untreated (Control) group; (b) CO2 group; (c) Nd:YAG group. All samples were then sintered and veneered with porcelain according to the manufacturer’s instructions. Surface morphology was examined using a light microscope, the surface roughness test was done by the atomic force microscope (AFM), and the shear bond strength (SBS) test was done by a universal testing machine. After debonding following shear bond test, zirconia surfaces were examined under a light microscope to determine their fracture mode. Results: The Results of this study showed that the lowest SBS was recorded in the control group, and the highest SBS recorded in the Fractional CO2 group, followed by the Q switched Nd:YAG laser group, as well as an increase in surface roughness and change in the morphology and mode of failure in the experimental groups . Conclusion: This study shows that Fractional CO2 laser and Q switched Nd:YAG laser treatments significantly increase the bond strength than untreated zirconia .
The subgrade soil is the foundation plate form of the roadway; it should sustain its structural characteristics throughout the design life of the roadway with minimal requirements for maintenance. When Gypseous soil is implemented in the construction of subgrade, problems regarding collapsibility and poor structural capacity usually occur when the subgrade came in touch with excess water. Asphalt stabilization could furnish a proper solution to such problems. In this investigation, an attempt has been made to monitor the variations in compressibility characteristics of asphalt stabilized subgrade soil subjected to 30 cycles of (freezing-thawing) and (heating-cooling). Data have been observed after each 10 cycles, and compared with that of r
... Show MoreThe region is defined by the spatial dimension, which consists of a set of stabilizers (towns and villages). The concept of the territory requires conditions on the nature of functional relations and the mutual influence of the regions within the region. Any territory must be based on the interdependence and interaction between the mother city and its surrounding countryside and cities, and when the interdependence is strong and the interaction is clear, it helps to define the territory. The regions are divided on different bases. There are geographically or national homogeneous regions, and there are cultural regions that want to preserve their culture in terms of language or religion. There are administrative regions to manage
... Show MoreThiamine stimulates the production of a red pigment , which is chromatographically and spectrophotometrically identical to prodigiosin , by growing cultures of serratia marcescens mutant 9-3-3 . this mutant is blocked in the formation of 2- methyl -3- amyl pyrorol( MAP),the monopyrrole moiety of prodigiosin , but accumulates 4-methoxy-2, 2-bipyrrole -5- carboxaldehyde (MBC) and can couple this compound with( MAP) to form prodigiosin . Addition of thiamine caused production of( MAP) , and as little as 0.02 mg of thiamine / ml in peptone- glycerol medium stimulated production of measurable amounts of prodigiosin. Phosphate saltes and another type of peptone decreased the thiamine- induced formation of prodigiosin ,yeast extract and glyc
... Show MoreThis research paper is about thevariationin the degree of Continentality climate of the
Iraq during (40) years for a number of climate station. Using Poresof formula, it is found out
that the climate of Iraq ranges between extreme Continentality and very extreme
Continentality, and that the Continentality degree is characterized with extreme frequency
from one year to another. In certain years, the degree of climate Continentality decreases
while in other years it rises in such a way that there is no similarity in the Continental degree
from one year to another for the same station.
As for the general trend of the degree of Continentality, the last years had noticed
special variations, which are divided in to thre
For a nonempty subset X of a group G and a positive integer m , the product of X , denoted by Xm ,is the set Xm = That is , Xm is the subset of G formed by considering all possible ordered products of m elements form X. In the symmetric group Sn, the class Cn (n odd positive integer) split into two conjugacy classes in An denoted Cn+ and Cn- . C+ and C- were used for these two parts of Cn. This work we prove that for some odd n ,the class C of 5- cycle in Sn has the property that = An n 7 and C+ has the property that each element of C+ is conjugate to its inverse, the square of each element of it is the element of C-, these results were used to prove that C+ C- = An exceptio
... Show MoreA one-dimensional hydraulic model was conducted to simulate the flow in Diyala River. The research aims to study the flow capacity along Diyala River and especially concerning on reach of the river within Baqubah City during flood seasons by using HEC-RAS, 5.07 software. Moreover, specifying the hydraulic problems and then the necessary treatments to overcome them were suggested. A 190 km length of the reach of Diyala River was included in this study, starts from Diyala submerged weir to the confluence of Diyala-Tigris River south of Baghdad City. Good agreement resulted between the measured and the simulation results with a determination coefficient (R2) value of 0.84 with Manning Co
God has honored the man with life and decent living and warned against attacking anything that violates his sanctity without a legitimate right. Our Islamic Shari'ah has the rights to preserve the right of a Muslim in the event of any harm.
Batch reactive distillation was studied in packed bed column. Esterification of methanol with acetic acid to produce methyl acetate and water with homogenous sulfuric acid as a catalyst was considered. This system was chosen because the reaction is reversible and the boiling point of reactant and products are different.
The reaction was carried out with and without distillation column and shows that the reactive distillation is more efficient from the conventional process (reactor and then separation). The conversion of acetic acid and concentration of methyl acetate increase by (30.43% and 75.14%) respectively at the best condition (reflux ratio 2, feed mole ratio 2 and batch time 90 minute).
The influence of various parameters, s
Vitiligo is an acquired idiopathic skin disorder characterized by depigmented macules due to loss of cutaneous melanocytes. A potential role of the immune dysfunction has been suggested in vitiligo, so to test this hypothesis, certain cytokines (IL-17A and TNF-?) and immunoglobulins (IgM, IgG, IgA and total IgE) were investigated in all participants. The study included: 60 patients with age range between (6-55) year; 30(11 males and 19 females) were untreated and 30(12 males and 18 females) were treated with Narrow Band Ultraviolet-B (NB-UVB) and 30 (14 males and 16 females) apparently healthy control. Serum was separated and cytokines (IL-17A and TNF-?) and total immunoglobulin E (IgE) were detected by using Enzyme Linked Immunosorbent Ass
... Show MoreAl-Huweizah Marsh is considered as the largest in Iraq. This research aims to maintain thesustainability of Al-Huweizah Marsh under all circumstances and within the limits of the
available natural resources from the Iraqi side and the absence of feeding from the Iranian sidedue to the recent Iranian separation dike along the international boundaries within the marsh.
Twelve scenarios have been suggested as a first step to restore the whole marsh. But the
uncontrolled Iranian feeders and exiguity of their discharges recently, it was necessary to studyonly the northern part of the marsh as an alternative case to ensure reasonable amounts of waterfor the purpose of maintaining and restore the marsh. Hydrological routing model was