Introduction: This study aimed, effect of platelet-rich Plasma (PRP) on soft tissue healing after mandibular third molar surgery. Materials & Methods: In this semi-blinded clinical trial study, 30 selected patients requiring surgical extraction of soft tissue impacted mandibular third molar participated from cases referred to the Department of Surgery, Faculty of Dentistry, Isfahan Azad University 2017. Patients divided into both test and control groups. PRP was placed in the extracted socket of the test group, whereas the control group had no PRP. Arzhangian standard kit utilized for preparation of PRP. The outcome variables in this study were pain, swelling, inter incisal mouth opening, wound dehiscence, dry socket, bleeding, and tissue color. The collected data analyzed using statistical tests followed independent T-test, Mann-Whitney, and fisher (p value < 0. 05). Results: The mean postoperative pain score (Visual Analog Scale) lowered for the test group after several wound dehiscence on the third and seventh days after surgery which was statistically significant (p value < 0. 001). Although the mean bleeding time on the third day after surgery decreased in the test group, this difference was not statistically significant (p value = 0. 59). There were no statistically significant between both groups for The dry socket incidence on the seventh day and the mean of inter incisal mouth opening in the third and seventh days after surgery as well. Conclusion: The usage of topical PRP has beneficial advantages on soft tissue healing after mandibular third molar surgery. Unlike the control group, The PRP group provided reduced pain and better soft tissue healing.

In this paper, thermal effect of Plasma arc Welding is investigated, and temperature field of ferrite stainless steel is acquired. Thermal effect of Plasma arc and subsequently the generated temperature field in the work piece is the key for analysis and optimization of this Welding process, which is the main goal of this paper. Finite element simulation of Welding process by SIMPLEC method and ANSYS software is achieved, using FSI solver for getting stainless steel temperature field, effect of parameters variation on temperature field, and process optimization for different situations of Plasma and shielding gases (Argon, Helium, and mixture of both). Lastly, the results of other papers are used to verify the correctness of this paper’s results. The temperate field results have determined the effects of Welding parameters, and are used to optimize Plasma Welding process for improving weld quality. Optimization results for different gases indicates that due to special heat of Helium gas, there is extra potential with respect to Argon gas to narrow the Plasma arc and concentrate inlet heat over stainless steel.

In this investigation, the effect of Plasma arc Welding (PAW) process parameters on the Welding quality of Ti-6Al-4V alloys is studied. These parameters including current, Welding linear velocity and Plasma gas composition that affected on the weld bead width. Macrograph results indicated that there is a certain range of electric current and linear velocity, which within the range, the full penetration Welding obtains, and the weld bead is free from defect. As a result, the mechanical properties are favorable and comparable to those of the base material. It can be protected weld bead from oxidation with argon gas (5N). Furthermore, the automation of the process resulted in repeatability of the Plasma arc Welding is very good and the weld quality is well controlled. The results indicated that increasing the amount of helium gas, increases the Welding area and the higher penetration depth of the weld. Examination of the microstructure of the weld region shows that there are three serrated alpha phase, alpha-beta phase (Widmanstä tten) and the martensitic phase in the weld microstructure.

To obtain the transient temperature in different parts of the body and the Welding pool growing, the continuity and momentum equations are solved along with the energy equation. The analysis for a rectangular plate made of AISI 304 Stainless Steel is done by writing a program with Fortran.90. Because the Fourier heat transfer equation at short times and large dimensions does not have sufficient accuracy a non-Fourier form of heat transfer equation is being used. Gaussian heat source is considered as a heat source model. The governing equations for fluid flows are solved by the finite volume method in which the SIMPLE method is used for calculating pressure-velocity coupling in fluid flows, likewise the Power-Law method and the staggered grid can be used for discretization equations. The finite difference method is also used to solve the energy equation. The effect of heat conduction, fluid flows and force actions at the weld pool is considered. Thermo-physical properties such as thermal conductivity, specific heat and dynamic viscosity are a function of temperature. There are two mechanisms, radiation and convection heat transfer, which actively cause heat transfer to the surroundings. The numerical results were compared with experimental data. Finally, the results obtained from the assumed Fourier heat transfer are compared for the same study. The results bear the fact that the weld pool thick in the cross section of keyhole PAW and the time that molten metal reaches to the end of thick metal, are in good agreement compared to experimental measurements.

Plain carbon steels are widely utilized in various industrial applications primarily due to their low cost. However, these steels often fall short in terms of mechanical properties and wear resistance. The deposition of hard and wear-resistant coatings on these steels significantly enhances their performance and extends their range of applications. Colomonoy 6, is a nickel-based superalloy, enhance hardness, erosion resistance, wear resistance, and corrosion resistance on the applied surfaces. The study investigated the application of weld overlay using colomonoy 6 on a plain carbon steel, aimed to create a hard and wear-resistant surface. The overlaying processes were performed using Plasma transfer arc Welding and gas tungsten arc Welding under identical conditions. Microstructural characteristics were examined through optical and electron microscopy, and Phase analysis was performed using X-ray diffraction technique. The wear behavior of the weld overlays was evaluated using pin-on-disc wear testing at three different temperatures: 25 °C, 300 °C, and 600 °C, using an alumina pin. The microstructural investigation revealed the formation of dendritic nickel-rich solid solutions and interdendritic carbide and boride phases within the overlays, contributing to improved hardness and wear properties. Results demonstrated that in both overlaying methods, the wear mechanism at room temperature was mild abrasive, whereas at 600 °C, it was plastic deformation, exhibiting a wear track depth of approximately 33-35 μm, and 50-55 μm, respectively. In both overlayed metals, an approximate Vickers hardness number of 600 was measured a 4-fold increase in hardness of substrate. This finding suggests that factors other than hardness, such as microstructural stability and phase distribution at elevated temperatures, play significant roles in wear performance.

Inconel 718 is used in a wide range of industries such as oil and gas, nuclear, aviation, and etc. due to its excellent mechanical properties. The use of additive manufacturing (AM) to manufacture parts is increasing rapidly Due to the dimensional limitations in the manufacturing of parts using the additive manufacturing methods, these parts must be connected to other parts in different applications with the help of conventional methods such as Welding. In this research, the thermal analysis of Plasma Welding of an Inconel 718 sheet made by SLM method using ABAQUS software is discussed. Input heat with Gaussian distribution was entered into the model by DFLUX subprogram with FORTRAN program language. In order to validate the thermal model, the temperature was measured during the Welding process using a thermocouple. A relatively good match is observed between the numerical and experimental thermal analysis results. The microstructure of the welded samples was examined with an optical microscope and the microstructure of base metal, fusion zone, and heat affected zone were investigated. The dendritic structure in the Welding area and the occurrence of recrystallization in the heat-affected area was evident. The tensile test results showed that the sample without Welding has a higher yield and ductility.