This work introduces a new electrode geometry for making holes with high aspect ratios on AISI 304 using an electrical discharge drilling (EDD) process. In addition to commercially available cylindrical hollow electrodes, an elliptical electrode geometry has been designed, manufactured, and implemented. The principal aim was to improve the removal of debris formed during the erosion process that adversely affects the aspect ratio, dimensional accuracy, and surface integrity. The results were compared and discussed to evaluate the effectiveness of electrode geometry on the machining performance of EDD process with respect to the material removal rate (MRR,) the electrode wear rate (EWR), and the tool wear ratio (TWR). Dimensional features and surface characteristics of the drilled holes were also evaluated in aspects of overcut (OC), aspect ratio (AR), and surface roughness (SR). The experimental results revealed that an elliptical electrode is preferable for producing holes with good dimensional accuracy and improved surface quality. In addition, 3D models of flow field with liquid, gas, and solid phases are proposed for analyses of the interelectrode gap within the machining zone. Based on the results obtained from models, the elliptical electrode also exhibited good flushing capability for effective debris removal.
Background: The long term survival of dental implants is evaluated by the amount of crestal bone loss around the implants. Some initial loss of bone around dental implants is generally expected. There is reason to believe that reflecting a mucoperiosteal flap promotes crestal bone loss in the initial phase after an implant has been inserted. The surgical placement of a dental implant fixture is constantly changing and in recent years, there has been some interest in developing techniques that minimize the invasive nature of the procedure, with flapless implant surgery being advocated. The purpose of this study was to compare the radiographic level of the peri- implant bone after implant placement between traditional flapped surgery and f
... Show MoreThis paper presents a comparison study on thermal performance conic cut twist tape inserts in laminar flow of nanofluids through a constant heat fluxed tube. Three tape configurations, namely, quadrant cut twisted tape (QCT), parabolic half cut twisted tape (PCT), and triangular cut twisted (VCT) of twist ratio= 2.93 and cut depth= 0.5 cm were used with 1% and 2% volume concentration of SiO2/water and TiO
... Show MoreThe aim of this article is to solve the Volterra-Fredholm integro-differential equations of fractional order numerically by using the shifted Jacobi polynomial collocation method. The Jacobi polynomial and collocation method properties are presented. This technique is used to convert the problem into the solution of linear algebraic equations. The fractional derivatives are considered in the Caputo sense. Numerical examples are given to show the accuracy and reliability of the proposed technique.
The inelastic C2 form factors and the charge density distribution (CDD) for 58,60,62Ni and 64,66,68Zn nuclei has been investigated by employing the Skyrme-Hartree-Fock method with (Sk35-Skzs*) parametrization. The inelastic C2 form factor is calculated by using the shape of Tassie and Bohr-Mottelson models with appropriate proton and neutron effective charges to account for the core-polarization effects contribution. The comparison of the predicted theoretical values was conducted with the available measured data for C2 and CDD form factors and showed very good agreement.
The dynamic thermomechanical properties, sealing ability, and voids formation of an experimental obturation hydroxyapatite-reinforced polyethylene (HA/PE) composite/carrier system were investigated and compared with those of a commercial system [GuttaCore (GC)]. The HA/PE system was specifically designed using a melt-extrusion process. The viscoelastic properties of HA/PE were determined using a dynamic thermomechanical analyser. Human single-rooted teeth were endodontically instrumented and obturated using HA/PE or GC systems, and then sealing ability was assessed using a fluid filtration system. In addition, micro-computed tomography (μCT) was used to quantify apparent voids within the root-canal space. The data were statistically analys
... Show MoreIn the theoretical part, removal of direct yellow 8 (DY8) from water solution was accomplished using Bentonite Clay as an adsorbent. Under batch adsorption, the adsorption was observed as a function of contact time, adsorbent dosage, pH, and temperature. The equilibrium data were fitted with the Langmuir and Freundlich adsorption models, and the linear regression coefficient R2 was used to determine the best fitting isotherm model. thermodynamic parameters of the ongoing adsorption mechanism, such as Gibb's free energy, enthalpy, and entropy, have also been measured. The batch method was also used for the kinetic calculations, and the day's adsorption assumes first-order rate kinetics. The kinetic studies also show that the intrapar
... Show MoreThis study included the effect of Aged garlic extract (AgE) and Row garlic extract (RgE)as immune modulators for treating or redusing the infection of boiler by Gomboro. This is made of measuring the stress index and serum antibodies levels against Gomboro virous( GV) estimated by HI,the study also detected the effect of each extract as antioxidents in broiler by estimation of peroxynitrite in serum . 300 chicks infected with Gumboro diseas brought at day ( 21 ) old and divided into three groups , the first group A was given the ( RgE ) at level of 5% with drinking water , the group B was given 5% of ( AgE ) and group C is left as control group and wasn't given anything. &
... Show MoreAbstract
The research aims to identify the extent of the practice of social responsibility in accordance with the social dimension and diagnosis of constraints applied.
Find the problem represented by the Social Responsibility and obstacles facing application in Baghdad Municipality through their workers trends analysis.
The adoption of the statistical method to analyze the data and information gathering, and selected municipalities of Adhamiya and Kadhimiya deliberate manner applied as a state and municipal councils of both cities as representatives of the local community to be the subject of research and comparison between them to see the reality of soci
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