Applied Mechanics and Industrial Technologies

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Authors: Bai Bin Wang, Chi Fen Chang, Yan Ru Li, Thanh Nam Chau, Wein Duo Yang
Abstract: This study successfully synthesized manganese-doped calcium zirconate phosphor and manganese-doped strontium zirconate phosphor using the sol-gel method. We employed X-ray powder diffraction and fluorescence spectroscopy to analyze the crystal structure and spectral characteristics of both phosphors. In X-ray powder diffraction analysis, data related to manganese-doped calcium zirconate phosphor and manganese-doped strontium zirconate phosphor were compared using X-ray diffraction comparison software to confirm the crystal structures of both phosphors. The crystal structure of manganese-doped calcium zirconate phosphor was in accordance with orthorhombic perovskites belonging to the Pnma {62} space group. The lattice parameters were a=5.762 Å, b=8.017 Å, and c=5.591 Å; c/a=0.97; volume=258.3 Å3, and density=4.611 g/cm3. The crystal structure of manganese-doped strontium zirconate phosphor conformed to orthorhombic perovskites belonging to the Pnma {62} space group, and the lattice parameters were a=5.818 Å, b=8.204 Å, c=5.797 Å; c/a=0.996; volume=276.7 Å3, and density=5.446 g/cm3. Fluorescence spectroscopy indicated that the primary broadband peak of manganese-doped calcium zirconate phosphor was located at 396.6 nm in the excitation spectrum corresponding to the 4T2(4G)4T1(4P) energy level transition. In the emission spectrum, the primary broadband peak was located at 596.6 nm, corresponding to the 4T2(4D)4T2(4G) energy level transition. For manganese-doped strontium zirconate phosphor, the primary broadband peak was located at 496.6 nm in the excitation spectrum and at 696.6 nm in the emission spectrum, corresponding to the 4T1(4G)4T2(4D) and 4E(4G)4T1(4G) energy level transitions, respectively.
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Authors: Milad Heidari, Mohammed Rafiq Abdul Kadir, Ali Fallahiarezoodar, Muhamad Noor Harun, Mina Alizadeh, Jamal Kashani
Abstract: Total elbow arthroplasty has shown acceptable results to relieve pain, developing range of motion and treating diseases which cause severe joint destruction. The objective of this study is analysis of the stress distribution on unconstrained elbow prosthesis during the flexion motion along with the analysis of the effect of medial and lateral collateral ligaments. A three dimensional model of elbow joint and unconstrained elbow prosthesis was developed. Flexion active muscles' forces were assigned to the model for two different 30 and 90 flexion. Results show increasing the flexion angles decrease the stress of articular surfaces. Furthermore, results demonstrate the effect of ligaments on stress magnitude and distribution in implant is significant.
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Authors: Thanh Nam Chau, Yi Ting Sung, Bai Bin Wang, Wein Duo Yang
Abstract: Titanate nanotubes were synthesized by a solvothermal process at a low temperature in a highly alkaline water-methanol mixed solution. Powders were characterized by XRD, TEM, BET and UV-vis absorption spectroscopy. The as-prepared samples was tested by the adsorptive process and photodegradation reaction of methylene blue (MB) dye under visible-light irradiation. The results indicated that the titanate samples are synthesized in the methanol-water volume ratios of 10:90, 20:80 and 30:70 are still highly absorbability and all the titanate samples as-prepared have higher photocatalytic activities compared with TiO2 P25 in the degradation of MB under visible light irradiation.
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Authors: Kyoung Hoon Kim, Dong Joo Kim, Kyoung Jin Kim, Seong Wook Hong
Abstract: Gas turbine inlet fogging is a method of cooling intake air by injecting demineralized water in the duct through the special atomizing nozzles. Gas turbine cycles with inlet fogging could offer enhanced efficiency with low complexity, so the inlet air-cooling is considered the most cost-effective way to increase the power output as well as thermal efficiency of gas turbines. In this work the inlet fogging process is modeled based on the evaporation of droplets. Transient behaviors of the process are investigated with analytic expressions obtained by considering heat and mass transfer and thermodynamic relations. Effects of water injection ratio on the transient behaviors of temperature of mixed air, mass of liquid droplets, mass flux and heat transfer from the droplets are thoroughly investigated. Results show also the dependencies of system parameters on the critical injection ratio and evaporation time.
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Authors: Kyoung Hoon Kim, Dong Joo Kim, Kyoung Jin Kim, Seong Wook Hong
Abstract: Recently humidified gas turbine systems in which water or steam is injected have attracted much attention, since they can offer a high efficiency and a high specific power with a relatively low cost compared to combined-cycle gas turbine systems, and therefore they have a potential for future power generation. In this study, performance analysis of the wet compression process is carried out with an analytical modeling which was developed from heat and mass transfer, and thermodynamic analyses based on droplet evaporation. Wet compression variables such as temperature-averaged polytropic coefficient, compressor outlet temperature, and compression work are estimated. Parametric studies show the effect of system parameters such as droplet size, water injection ratio or compression ratio on transient behavior.
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Authors: Sina Alizadeh Ashrafi, Safian Sharif, Yahya Mohd Yazid, Ali Davoudinejad
Abstract: Drilling composite materials is challenging due to the anisotropic and non-homogenous structure of composites. In fabrication works, metals are joined to composites to form a hybrid strengthened structures, and this posed a great problem during drilling, due to the dissimilar drilling conditions for each material and also sharp metal chips effect on the quality of hole on composite plates. This paper evaluates the experimental results on the machining performance of coated and uncoated 4 facet carbide drills when dry drilling stack of carbon fiber reinforced plastic (CFRP) and aluminum. Drilling trials were carried out on CFRP/Al2024/CFRP stack at constant cutting speed of 37 m/min with three feed rates within 0.03-0.25 mm/rev. Results revealed that 4 facet coated drills performed better than uncoated drills in terms of delamination. It was found that hole entry delamination increases with increasing feed rate, however uncut fibers which were dominant at low feeds on hole exit, disappears with increasing feed rate. It was also found that thrust force for coated tools were quite higher than uncoated tools.
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Authors: Behzad Abdi, Yob Saed Bin Ismail, Ayob Amran, R.A. Abdullah, Mohd Yazid bin Yahya
Abstract: The most important concern in design of filament-wound composite pressure vessels reflects on the determination of the optimum shape and optimum laminate stacking sequence of composite vessels based on the matrix cracking pressure and burst pressure of composite laminates. In this study the Imperialist Competitive Algorithm (ICA) is used to find the optimum laminate stacking sequence of composite vessels that the design considerations are stability and strength constraints. the matrix cracking pressure of filament-wound composite pressure vessels made of different number of helical layers and different layers of Circumferential layers was calculated by using orthotropic material formulae and then, the burst pressure of composite vessels was calculated by using netting analysis. The optimum laminate stacking sequence of filament winding composite was found to maximize the matrix cracking pressure and the burst pressure by using Imperialist Competitive algorithm.
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Authors: Toms Torims, Andris Ratkus, Marcis Zarins, Valdis Brutans, Janis Vilcans
Abstract: Renovation of marine diesel engine crankshaft main and crankpin journals surfaces is usually done when ships engine is undergoing repairs. Often heavy working conditions and intensive wear accompanied with lubrication failures require a complete renovation of these worn-out surfaces. In most of the cases these repairs are done in the workshop, by removing crankshaft from engine and subsequently performing journal grinding. Where it is necessary also various types of build-up operations are carried out. Final technical requirements for these repairs are demanding: fine surface quality, geometrical accuracy and high surface roughness (texture) parameters have to be ensured. Although available technologies are able to deliver these results, they are very expensive, time consuming and usually can be done only in workshop conditions by highly sophisticated and expensive grinding machinery. This article describes novel technology which has been developed to perform crankshaft crankpin journal surfaces grinding operations directly in engine housing. Furthermore, a comprehensive study of laser build-up techniques and their potential applications for marine crankshaft specifics is outlined. Study confirmed that previously adopted grinding platform can be extended to laser cladding technology. It suites well shipboard crankshaft surface renovation needs and opens an entirely new industrial application dimension to the laser cladding technologies. Combination of these in-situ grinding and laser cladding technologies can bring considerable economic benefits and save the valuable marine diesel engine repair time.
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Authors: Yi Wu, Zhi Liu, Yu Jie Yang
Abstract: The segment is an important part of the slab caster. the designing and manufacturing of segment directly impact the quality of slab. It is necessary to research and analysis the segment. This paper analyses stress and deformation of segment. Firstly, specify the characteristic of segment structure, legitimately simplify the structure, figure out the force of every bearing box. Secondly, develop the 3-D model with SolidWorks software, then import it into ANSYS software, with which we develop the FEM model. Lastly, analysis FEM stress and deformation of FEM model, so the maximum stress and deformation is obtained. The state of stress is safe, but the stiffness is kind of insufficient. It can be improved in the designing process.
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