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.
Value Engineering is an analytical study on projects or services using a specific procedure and a multidisciplinary working group, works for the identification and classification of the project functions; either for a better perfuming of these functions or to lessen the total project cost or the two together. Value Engineering main aim is on finding innovative alternatives, without effecting the basic requirements of the project, its methodology based on the functional balancing between the three elements of production "performance, quality and cost". This methodology based on the "functional analysis", had shown high possibilities in solving any problem facing the production procedure , achieve better investment for available re
... Show MoreAs a result of the increase in wireless applications, this led to a spectrum problem, which was often a significant restriction. However, a wide bandwidth (more than two-thirds of the available) remains wasted due to inappropriate usage. As a consequence, the quality of the service of the system was impacted. This problem was resolved by using cognitive radio that provides opportunistic sharing or utilization of the spectrum. This paper analyzes the performance of the cognitive radio spectrum sensing algorithm for the energy detector, which implemented by using a MATLAB Mfile version (2018b). The signal to noise ratio SNR vs. Pd probability of detection for OFDM and SNR vs. BER with CP cyclic prefix with energy dete
... Show MoreArabian Political Regimes: Problems of Policies and Rule; An Introduction to Interpreting (The Arabian Spring) The Arab Region witnessed, since 2011, critical changes overthrew a group of Arab regimes in some of its countries, and the reaction of these changes are still going on up to now. These changes were given lots of justifications and interpretations. The current study tries to concentrate on the most important problems which were due to what was known as (The Arab Spring). The study proposes that the crisis which the countries of the area are exposed to is not spontaneous in many of its aspects. It is totally a crisis of rule and policies. Because it is a reflection of the nature of authority in the Arabian regimes on the one hand
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Westernization is a term not familiar to our scholars at the beginning of the emergence of translation from Western literature, sciences and arts in its detailed form now.
Westernization was not an issue that those Greeks, Persians, Romans, Indians and others worked on translating those sciences and cultures. Rather, it was a process of transferring a new philosophy and logic that had not been previously seen by the Arabs, so they were affected by it in a strange way, to the point of fascination by some of them. For this reason, this research came to clarify these issues and address them within the scientific methodology.
Indium doped CdTe polycrystalline films of thickness equals to 300nm were grown on corning glass substrates at temperature equals to 423K by thermal co-evaporation technique. The structural and electrical properties for these films were studied as a function of heat treatment (323,373,423)K. The x-ray analysis showed that all samples are polycrystalline and have the cubic zincblende structure with preferential orientation in the [111] direction, no diffraction peaks corresponding to metallic Cd, Te or other compounds were observed. It was found that the electrical resistivity drops and the carrier concentration increases when the CdTe film doped with 1.5% indium and treated at different annealing temperatures.
Obtaining the computational models for the functioning of the brain gives us a chance to understand the brain functionality thoroughly. This would help the development of better treatments for neurological illnesses and disorders. We created a cortical model using Python language using the Brian simulator. The Brian simulator is specialized in simulating the neuronal connections and synaptic interconnections. The dynamic connection model has multiple parameters in order to ensure an accurate simulation (Bowman, 2016). We concentrated on the connection weights and studied their effect on the interactivity and connectivity of the cortical neurons in the same cortical layer and across multiple layers. As synchronization helps us to mea
... Show MoreTo assess the use of miniaturized percutaneous nephrolithotomy (mini-PCNL) for renal stones in children, as well as its safety and efficacy. Seventy-seven patients with more than 15 mm renal stones whose age was less than 15 years were enrolled in this prospective case-controlled study at Al-Ramadi Teaching Hospital, Ar Razi Private Hospital, and Ghazi Al-Hariri Hospital for Surgical Specialties, Anbar and Baghdad, Iraq. The study was conducted from January 2020 to January 2024. The group mentioned above served as group A, and it was compared to the control group (group B), which consisted of 70 adult patients aged 18–60 years. Patients in both groups underwent mini-PCNL. Gender, stone size and location, time of operation, stone-free rate
... Show MoreIn this paper, we introduce and study the essential and closed fuzzy submodules of a fuzzy module X as a generalization of the notions of essential and closed submodules. We prove many basic properties of both concepts.
A.R. Ammons's Garbage is a unique poem in all measures, starting from the title to the subject matter of the poem. Though it discusses the ecological repercussion of waste management, the long poem is written to shed light on the correlation between language\poetry and garbage. The paper argues that in his examination of language\poetry and garbage as both reflectors of human life and experience, Ammons claims that redemption is possible through both language and garbage by scrutinizing human experience whether low or high, mundane or sacred. This paper tries to examine Ammons's efforts to use the farfetched metaphor of garbage to discuss language and poetry-writing.