Background: The present study was carried out to compare shear bond strength of sapphire bracket bonded to zirconium surface after using different methods of surface conditioning and assessment of the adhesive remnant index. Materials and methods: The sample composed of 40 zirconium specimens divided into four groups; the first group was the control, the second group was conditioned by sandblast with aluminum oxide particle 50 μm, the third and fourth group was treated by (Nd: YAG) laser (1064nm)(0.888 Watt for 5 seconds) for the 1st laser group and (0.444 Watt for 10 seconds) for the 2nd laser group. All samples were coated by z-prime plus primer. A central incisor sapphire bracket was bonded to all samples with light cure adhesive resin. Shear bond strength was measured by using Tinius Olsen universal testing machine. After debonding, each bracket and zirconium surface were examined and adhesive remnant index was registered. The difference in shear bond strength among groups was analyzed by using ANOVA test. The adhesive remnant index was assessed using Chi-square test. Results: The 2nd laser group had the highest mean value of shear bond strength then the 1st laser group followed by the sandblasting group, while the control group had the least value, non-significant difference in the shear bond strength was found between the laser groups and highly significant difference was found between all other comparable groups. Non-significant difference in the site of bond failure was found between the laser groups and sandblasting group, and between the two laser groups. Conclusion: The laser conditioning method showed higher value of shear bond strength than the sandblasting conditioning method.
In many oil fields only the BHC logs (borehole compensated sonic tool) are available to provide interval transit time (Δtp), the reciprocal of compressional wave velocity VP.
To calculate the rock elastic or inelastic properties, to detect gas-bearing formations, the shear wave velocity VS is needed. Also VS is useful in fluid identification and matrix mineral identification.
Because of the lack of wells with shear wave velocity data, so many empirical models have been developed to predict the shear wave velocity from compressional wave velocity. Some are mathematical models others used the multiple regression method and neural network technique.
In this study a number of em
... Show MoreIn this study we surveyed the dominant normal stool flora of randomly selected healthy, young (18-23 years old), unmarried (doctrinal) Iraqi college students (males and females) for the carriage of extraintestinal pathogenic E. coli (ExPEC). ExPEC virulence was detected phenotypically by mannose resistant hemagglutination of human red blood cells (MRHA) and mannose sensitive (MS) agglutination of Bakers' yeast (Saccharomyces cerevisceae). From 88 college students, 264 E. coli isolates were obtained (3 isolates per person): 123 from 41 females and 141 from 47 males. Of these isolates, 56% (149/264) caused MS agglutination of yeast cells and 4.16% (11/264) showed MRHA. Eighty two percent (9/11) of the isolates with MRHA also caused MS agglu
... Show MoreThe adsorption ability of Iraqi initiated calcined granulated montmorillonite to adsorb of 4-(4-Nitrobenzeneazo) 3-Aminobenzoic Acid from aqueous solutions has been investigated through columnar method. The azo dye adsorption found to be dependent on adsorbent dosage, initial concentration and contact time. All columnar experiments were carried out at three different pH values (5.5, 7and 8) using buffer solutions at flow rate of (3 drops/ min.), at room temperature (25±2) °C. The experimental isotherm data were analyzed using Langmuir, Freundlich and Temkin equations. The monolayer adsorption capacity is 6.4066 mg Azo ligand per 1g calcined Montmorillonite. The experiments showed that highest removal rate 90.5 % for azo dye at pH 5.5.The
... Show MoreThe research seeks to examine the image of women in Iraqi films produced after 2003 over the answer to questions such as “ level of the representation of women and appearing in films and features that are attributable to them and their relationships with men and their interests and tendencies , activities and ways and methods pursued to achieve their goals , or what appeared to be trying to achieve and whether made movies vivid and varied models for women, or confined to a rigid model and duplicate Is films raised issues concerning women? The research seeks to examine the image of women in Iraqi films produced after 2003 over the answer to questions such as “ level of the representation of women and appearing in films and features th
... Show MoreIn this study, an experimental investigation had conducted for six high strength laced reinforced concrete one-way slabs to discover the behavior of laced structural members after being exposed to fire flame (high temperature). Self-compacted concrete (SCC) had used to achieve easy casting and high strength concrete. All the adopted specimens were identical in their compressive strength of ( , geometric layout 2000 750 150 mm and reinforcement specifics except those of lacing steel content, three ratios of laced steel reinforcement of (0.0021, 0.0040 and 0.0060) were adopted. Three specimens were fired with a steady state temperature of for two hours duration and then after the specimens were cooled suddenly by spraying water. The
... Show MoreUrbanization led to significant changes in the properties of the land surface. That appends additional heat loads at the city, which threaten comfort and health of people. There is unclear understanding represent of the relationship between climate indicators and the features of the early virtual urban design. The research focused on simulation capability, and the affect in urban microclimate. It is assumed that the adoption of certain scenarios and strategies to mitigate the intensity of the UHI leads to the improvement of the local climate and reduce the impact of global warming. The aim is to show on the UHI methods simulation and the programs that supporting simulation and mitigate the effect UHI. UHI reviewed has been conducted the for
... Show MoreThe phytoremediation technique has become very efficient for treating soil contaminated with heavy metals. In this study, a pot experiment was conducted where the Dodonaea plant (known as hops) was grown, and soil previously contaminated with metals (Zn, Ni, Cd) was added at concentrations 100, 50, 0 mg·kg-1 for Ni and Zn, and at concentrations of 0, 5, 10 mg·kg-1 for cadmium. Irrigation was done within the limits of the field capacity of the soil. Cadmium, nickel and zinc was estimated in the soil to find out the capacity of plants to the absorption of heavy and contaminated metals by using bioconcentration factors (BCFs), bioaccumulation coefficient (BAC) and translocation factor (TF). Additionally, BCF values of both Ni and Zn were l
... Show MoreThe Effect of Chicken Eggshell Extract on Microhardness of Artificially Induced Dental Erosion in Permanent Teeth (In Vitro Study), Shatha A Abbas*, Alhan A Qasim