Background. “Polyetheretherketone (PEEK)” is a biocompatible, high-strength polymer that is well-suited for use in dental applications due to its unique properties. However, achieving good adhesion between PEEK and hydrophilic materials such as dental adhesives or cement can be challenging. Also, this hydrophobicity may affect the use of PEEK as an implant material. Surface treatment or conditioning is often necessary to improve surface properties. The piranha solution is the treatment of choice to be explored for this purpose. Methods. PEEK disks of 10 mm diameter and 2 mm thickness were used in this study. Those samples were divided into five groups (each group has five samples). The first is the control group, in which no acid treatment was used; the second group undergoes sulfuric acid treatment. The remaining three groups were treated with Piranha solution; each group used a different concentration (1 : 3, 1 : 5, and 1 : 7 hydrogen peroxide to sulfuric acid, respectively). The period of treatment was 60 s for all groups. Wettability and surface roughness tests were done for the five groups. In statistical analysis, Shapiro–Wilk test was used to check the assumption of normality and to determine the statistical significance among groups; a one-way analysis of variance was employed. Subsequently, for multiple comparisons, Tukey’s honestly significant difference post hoc test was performed. Results. The Piranha solution treatment groups showed a higher wettability compared to the control group and the group treated with sulfuric acid. Additionally, the Piranha solution treatment with a higher concentration of hydrogen peroxide (1 : 3) resulted in greater improvement in surface roughness compared to the control group and the lower concentration groups (1 : 5 and 1 : 7), while the sulfuric acid treated group showed the highest surface roughness. Conclusion. The results of this study suggest that the piranha solution can be an effective method for improving the surface characteristics of PEEK to be used in different dental applications, especially as a dental implant material, due to the increase in wettability and surface roughness.
The large number of failure in electrical power plant leads to the sudden stopping of work. In some cases, the necessary reserve materials are not available for maintenance which leads to interrupt of power generation in the electrical power plant unit. The present study, deals with the determination of availability aspects of generator in unit 5 of Al-Dourra electric power plant. In order to evaluate this generator's availability performance, a wide range of studies have been conducted to gather accurate information at the level of detail considered suitable to achieve the availability analysis aim. The Weibull Distribution is used to perform the reliability analysis via Minitab 17, and Artificial Neural Networks (ANNs) by approaching o
... Show MoreIn the present study, advanced oxidation treatment, the TiO2 /UV/H2O2 process was applied to decolorisation of the reactive yellow dyes in aqueous solution. The UV radiation was carried out with a 6 W low-pressure mercury lamp. The rate of color removal was studied by measuring the absorbency at a characteristic wavelength. The effects of H2O2 dosage, dye initial concentration and pH on decolorisation kinetics in the batch photoreactor were investigated. The highest decolorisation rates were observed (98.8) at pH range between 3 and 7. The optimal levels of H2O2 needed for the process were examined. It appears that high levels of H2O2 could reduce decolori
... Show MoreAs one type of heating furnaces, the electric heating furnace (EHF) typically suffers from time delay, non-linearity, time-varying parameters, system uncertainties, and harsh en-vironment of the furnace, which significantly deteriorate the temperature control process of the EHF system. In order to achieve accurate and robust temperature tracking performance, an integration of robust state feedback control (RSFC) and a novel sliding mode-based disturbance observer (SMDO) is proposed in this paper, where modeling errors and external disturbances are lumped as a lumped disturbance. To describe the characteristics of the EHF, by using convection laws, an integrated dynamic model is established and identified as an uncertain nonlinear second ord
... Show MoreRemoval of heavy metal ions such as, cadmium ion (Cd 2+) and lead ion (Pb 2+) from aqueous solution onto Eichhornia (water hyacinth) activated carbon (EAC) by physiochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO2) as the activating agents were investigated. The Eichhornia activated carbon was characterized by Brunauer Emmett Teller (BET), Fourier Transform Infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) techniques. Whereas, the effect of adsorbent dosage, contact time of pH, and metal ion concentration on the adsorption process have been investigated using the batch process t
Smear zone is usually formed around the prefabricated vertical drains (PVD’s) due to mandrel driving. The geotechnical properties of the soil in this zone exhibit significant changes that affect the performance of the PVD’s. The most relevant property in this respect is the coefficient of permeability. So far, no serious attention is paid to investigate the effects of shearing under large shear strains on the geotechnical properties of the soft soil in Fao region. In this study, an extensive laboratory testing program was conducted to assess the characteristics of the smear zone with an emphasis on the permeability coefficient of Fao soft soil. The results show that the permeability of the smear zone is about 70% of
... Show MoreTo accommodate utilities in buildings, different sizes of openings are provided in the web of reinforced concrete deep beams, which cause reductions in the beam strength and stiffness. This paper aims to investigate experimentally and numerically the effectiveness of using carbon fiber reinforced polymer (CFRP) strips, as a strengthening technique, to externally strengthen reinforced concrete continuous deep beams (RCCDBs) with large openings. The experimental work included testing three RCCDBs under five-point bending. A reference specimen was prepared without openings to explore the reductions in strength and stiffness after providing large openings. Openings were created symmetrically at the center of spans of the other specimens
... Show MoreStatic Synchronous Series Compensator (SSSC) is a well known device for effectively regulating the active power flow in a power system. In this paper, the SSSC linearized power flow equations are incorporated into Newton-Raphson algorithm in a MATLAB written program to investigate the control of active poweer flow and the transient stability of a five bus and a thirty bus IEEE test systems, during abnormal conduction (three phase fault near buses). A comparison of the results obtained for the base case without SSSC and with it to investigate the effectiveness of the device on both of the active power flow and the transient stability.
Thermal management has become a major issue in the latest high performance computing machines because high CPU temperatures result in inefficient performance and decreased hardware life span. In this work, the cooling performance of a finned metal foam heat sink (FMFHS) was examined. The pore density values of tested copper metal foam (CMF) samples with different values of PPI 5, 10 and 20, with a constant porosity of 90%. For reference, these samples were measured by a conventional Aluminum plate-fin heat sink (CHS). The work was performed under experimental conditions in which air directed over the heat sink surface at air velocities (2.5, 3.0 and 3.5 m/s). The environmental temperature was fixed at 27 °C. Findings
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