Background: Separation and deboning of artificial teeth from denture bases present a major clinical and labortory problem which affect both the patient and the dentist. The optimal bond strength of artificial teeth with denture base reinforced with nanofillers and flexible denture bases and the effect of thermo cycling should be evaluated. This study was conducted to evaluate and compare the shear bond strength of artificial teeth (acrylic and porcelain) with denture bases reinforced by 5% Zirconium oxide nanofillers and flexible bases under the effect of different surface treatments and thermo cycling and comparing the results with conventional water bath cured denture bases. Material and methods: Two types of artificial teeth; acrylic and porcelain were used and prepared for this study. Five specimens of each tooth type were processed to each denture base materials after the application of different surface treatments; these teeth were bonded to heat polymerized, nano composite resin and flexible denture bases. Specimens were thermo cycled and tested for bond strength until fracture with an Instron universal testing machine. Data were analyzed with analysis of variance and student T-test. Photomicrographic examinations were used to identify adhesive and cohesive failures within debonded specimens. Results: The mean force required to fracture the specimens were obviously larger for nanocomposite specimens compared with the heat cured and flexible specimens. The most common failure was cohesive within the tooth or the denture base. With each base material, the artificial teeth which were treated with thinner exhibited highest shear bond strength. Thermocycling had deleterious effect on the flexible denture base specimens. In general, nanocomposite and heat cured groups failed cohesively within the artificial tooth. While the valplastic groups failed adhesively at the tooth denture base interface. Conclusions: Within the limitations of this study, the type of denture base materials and surface treatments of the tooth selected for use may influence the shear bond strength of the tooth to the base. Selection of more compatible combinations of base and artificial teeth may reduce the number of prosthesis fractures and resultant repairs. Key words: acrylic teeth, porcelain teeth, Nano composite denture base, thermo cycling, flexible denture, thinner,
oday deep ocean life has not been discovered by humans including many secret world things to be explored. The researcher has focused on underwater optical wireless communications using various kinds of complex digital Signal processing most of them used in air and starting applied in underwater communication. The Internet of Things (IoT) uses underwater called Internet of Underwater Things (IoUT) applications to explore the underwater world with other devices. However, the difference in concentration between air and water surfaces is not easy making wireless communication more complicated. Visible light passes the water's surface with scattering and distortion inside the water and each color of light has different attenuation the blue laser
... Show MorePhotonic crystal fiber interferometers are widely used for sensing applications. In this work, solid core-Photonic crystal fiber based on Mach-Zehnder modal interferometer for sensing refractive index was presented. The general structure of sensor applied by splicing short lengths of PCF in both sides with conventional single mode fiber (SMF-28). To apply modal interferometer theory; collapsing technique based on fusion splicing used to excite higher order modes (LP01 and LP11). Laser diode (1550 nm) has been used as a pump light source. Where a high sensitive optical spectrum analyzer (OSA) was used to monitor and record the transmitted. The experimental work shows that the interference spectrum of Photonic crystal fiber interferometer
... Show MoreNatural dye sensitized solar cell was prepared using strawberry and pomegranate dyes with anatase nanocrystalline titanium dioxide powder. A study of the optical properties of the two dyes, involving the absorption spectrum was determined in the visible region. I-V characteristics under illumination were performed. The results showed that the two prepared dye sensitized solar cells have acceptable values efficiency about (0.94 with Fill factor (45)) and (0.74 with Fill factor (44)) for strawberry and pomegranate dyes, respectively.
In the last years of the twentieth century, scholars solidly focused on paradiplomacy as a study subject, linking it to federalism and decentralised systems. In the Arab world, which has 22 countries, a few states have adopted federalism or decentralisation. Only five countries, i.e., 22.7%, have adopted federalism and decentralised experience. Therefore, limited research and academic work has been conducted regarding paradiplomacy. This paper aims to research the relationship between federalism and paradiplomacy conceptually and practically and then analyse the Arab experiences in federalism and whether they applied paradiplomacy and succeeded in doing so. To explore that, the paper studies and compares the related articles of constitution
... Show MoreClassification of imbalanced data is an important issue. Many algorithms have been developed for classification, such as Back Propagation (BP) neural networks, decision tree, Bayesian networks etc., and have been used repeatedly in many fields. These algorithms speak of the problem of imbalanced data, where there are situations that belong to more classes than others. Imbalanced data result in poor performance and bias to a class without other classes. In this paper, we proposed three techniques based on the Over-Sampling (O.S.) technique for processing imbalanced dataset and redistributing it and converting it into balanced dataset. These techniques are (Improved Synthetic Minority Over-Sampling Technique (Improved SMOTE), Border
... Show MoreWeb testing is very important method for users and developers because it gives the ability to detect errors in applications and check their quality to perform services to users performance abilities, user interface, security and other different types of web testing that may occur in web application. This paper focuses on a major branch of the performance testing, which is called the load testing. Load testing depends on an important elements called request time and response time. From these elements, it can be decided if the performance time of a web application is good or not. In the experimental results, the load testing applied on the website (http://ihcoedu.uobaghdad.edu.iq) the main home page and all the science departments pages. In t
... Show MoreLanguage is an important means through which one can construct one's social world. Accordingly, the way we view ourselves and the world is basically formed by language use whereby identities, relations, and values are constructed and maintained. Most discourse analysts consider narrative not only the locus of construction and enactment of identity, but also a distinguished genre for its analysis.The present study is concerned with how identity can poetically be informed, hence exploring the way black poets use language when reflecting their identity and culture. The poem, right on: white america by the black American poetess Sonia Sanchez, is chosen to be analyzed based on Simpson's stylistic model (2004). In this model, the ana
... Show MoreCalculating the Inverse Kinematic (IK) equations is a complex problem due to the nonlinearity of these equations. Choosing the end effector orientation affects the reach of the target location. The Forward Kinematics (FK) of Humanoid Robotic Legs (HRL) is determined by using DenavitHartenberg (DH) method. The HRL has two legs with five Degrees of Freedom (DoF) each. The paper proposes using a Particle Swarm Optimization (PSO) algorithm to optimize the best orientation angle of the end effector of HRL. The selected orientation angle is used to solve the IK equations to reach the target location with minimum error. The performance of the proposed method is measured by six scenarios with different simulated positions of the legs. The proposed
... Show MoreThe presence of different noise sources and continuous increase in crosstalk in the deep submicrometer technology raised concerns for on-chip communication reliability, leading to the incorporation of crosstalk avoidance techniques in error control coding schemes. This brief proposes joint crosstalk avoidance with adaptive error control scheme to reduce the power consumption by providing appropriate communication resiliency based on runtime noise level. By switching between shielding and duplication as the crosstalk avoidance technique and between hybrid automatic repeat request and forward error correction as the error control policies, three modes of error resiliencies are provided. The results show that, in reduced mode, the scheme achie
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