Recent Advances in Materials, Mechanical and Civil Engineering

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作者: Ajay Kumar Revelly
摘要: The comparative study of Ga+ ion, Nb+ ion, proton and electron (H+ and e-) irradiation on single crystal and poly crystal Zirconium (Zr), characterised in terms of misorientation profile change, EBSD maps or microtexture, XRD residual stresses development and irradiation hardening effect. It was concluded that the rate of damage is varying with respect to irradiation source. In the present study both the Zr and its alloys were used to conclude this main objective.
作者: Bhargavi Gunturu, Geethalakshmi Ramakrishnan, Renganathan Sahadevan
摘要: In the present study, the efficiency of biosorbent derived form Pongamia pinata to remove a basic textile dye Methylene Blue from an aqueous solution was evaluated in batch system. The influence of adsorption parameters such as biosorbent dosage (0.2-1.0g/L), PH (2-10) and initial dye concentration (30-110 mg/L) on the biosorption process was studied. It was noticed that adsorbent dosage has negative effect on dye uptake, could be due to reduced mass transfer rate of dye on to adsorbent. High equilibrium uptake was observed at PH 8. However, initial dye concentration has shown linear relationship with dye uptake. As the dye concentration increases, the number of dye molecules available to be adsorbed on to adsorbent surface increases. Equilibrium isotherms for the adsorption of methylene blue was analyzed through Langmuir and Freundlich isotherm models. The data best fit with Freundlich model than Langmuir isotherm model, suggesting the adsorption was by multilayer mechanism. Maximum adsorption capacity (Q ̊) was found to be 40.49mg/g. It can be concluded from the study that the adsorbent derived from P. pinnata can be a potential low cost competent of activated carbon for textile dyes removal.
作者: P.K. Mandal
摘要: The cast Al-Zn-Mg 7000 alloy has become one of the most potential structural materials in many engineering fields such as aircraft body, automotive casting due to their high strength to weight ratio, strong age hardening ability, competitive weight savings, attractive mechanical properties and improvement of thermal properties. The cast aluminium alloy has been modified of surface layer through a solid-state technique is called friction stir process (FSP). But basic principle has been followed by friction stir welding (FSW). This process can be used to locally refine microstructures and eliminate casting defects in selected locations, where mechanical properties improvements can enhance component performance and service life. However, some specified process parameters have adopted during experimental works. Those parameters are tool rotation speed (720 rpm), plate traverse speed (80 mm/min), axial force (15 kN), and tool design (i.e., pin height 3.5 mm and pin diameter 3.0 mm), respectively. The main mechanism behind this process likely to axial force and frictional force acting between the tool shoulder and workpiece results in intense heat generation and plastically soften the process material. The specified ratio of rotational speed (720 rpm) to traverse speed (80 mm/min) is considered 9 as low heat input during FSP and its entails low Zn vaporization problem results as higher fracture toughness of aluminium alloy. It is well known that the stirred zone (SZ) consists of refine equiaxed grains produced due to dynamic recrystallization. FSP has been proven to innovatively enhancing of various properties such as formability, hardness and fracture toughness (32.60 MPa√m). The hardness and fracture toughness of double passes AC+FSP aluminium alloy had been investigated by performing Vicker’s hardness measurement and fracture toughness (KIC)(ASTM E-399 standard) tests. Detailed observations with optical microscopy, Vicker’s hardness measurement, SEM, TEM, and DTA analysis have conducted to analyse microstructure and fracture surfaces of double passes FSP aluminium alloy.
作者: Bhargavi Gunturu, Geethalakshmi Ramakrishnan, Renganathan Sahadevan
摘要: Removal of a basic textile dye Methylene Blue from an aqueous solution was evaluated using biosorbent derived from Kigelia africana in a batch system. The influence of adsorption parameters such as adsorbent dosage (0.10-0.50g), PH (2-12) and initial dye concentration (0.3 to 0.11 g/L) on the adsorption process was studied. It was noticed that with increase in adsorbent dosage, the uptake capacity was decreased. Dye uptake was increased by changing the PH up to 8, further increase in PH caused reduced uptake. It was observed that, dye uptake by the adsorbent increased linearly with that of initial dye concentration. Equilibrium isotherm for the adsorption of methylene blue on to adsorbent was studied through Langmuir and Freundlich isotherm models. The data best fit with Freundlich model. Maximum adsorption capacity (Q ̊) was found to be 119.05mg/g. SEM and FTIR analyses of the adsorbent was performed before and after the adsorption, suggest that adsorption of the dye was through chemical interaction of the functional groups on the surface of the adsorbent. From the experimental results, it was inferred that biosorbent derived from Kigelia africana can be a potential alternate to activated carbon for textile dyes removal.
作者: Kartick Lal Bhowmik, M. Kanmani, Akash Deb, Animesh Debnath, Ranendu Kumar Nath, Biswajit Saha
摘要: A facile co-precipitation method was established for synthesis of mesoporous iron-manganese magnetic bimetal oxide (MIMO) and its adsorption property was studied for removal of toxic metal ion hexavalent chromium from aqueous solution. XRD pattern of MIMO confirms the existence of Fe2O3 and Mn3O4 particle, out of which Mn3O4 is ferrimagnetic in nature. Synthesized MIMO has shown high saturation magnetization (23.08 emu/g), high BET surface area (178.27 m2/g) and high pore volume (0.484 cm3/g), which makes it a potential adsorbent. Adsorption process followed second order kinetic and Langmuir isotherm model. Involvement of intra-particle diffusion is also confirmed from kinetic data, which can be attributed to the mesoporous nature of the MIMO. Cr(VI) adsorption shows high pH dependency and maximum adsorption capacity of 116.25 mg/g is reported at pH 2.0. Electrostatic attraction between anionic chromium species and protonated MIMO surface is the predominant mechanism in this adsorption process.
作者: T. Antony Prabhu, N. Murugesan, S. Ingersol, D.P. Sudhakar, P.V. Venkitakrishnan
摘要: Ti-5Al-2.5Sn alloy is widely used in aerospace applications due to its high specific strength, low coefficient of thermal expansion and good corrosion resistance. Presence of interstitial elements in the alloy has some significant effects on its properties. However the high notch toughness and cryogenic ductility attracts the usage of Ti-5Al-2.5Sn for usage at cryogenic temperatures even at 20K. For hydrogen embrittlement studies and for investigating notch sensitivity of Ti-5Al-2.5Sn alloy, the notched and smooth specimens from ELI grade of Ti-5Al-2.5Sn alloy were subjected to LH2 exposure and tensile test at 20K (-253°C) and at 77K (-196°C). The tensile properties obtained from different specimens were compared and analyzed. Also the notch to smooth tensile strength ratio (NSR) were compared and analysed. The obtained NSR was above unity which confirms the low notch brittleness. The tensile strength values between LH2 exposed and unexposed specimen at 20K and 77K were compared and it revealed greater compatibility of Ti-5Al-2.5Sn-ELI with liquid hydrogen environment.
作者: Nisha Kumari, Kaushik Kumar
摘要: Increasing population has led to numerous disabilities. One such disability which should be taken into account is related to human gait. Polio patients mainly suffer from this kind of disability due to which their muscles get weakened and they are unable to walk properly. The handicapped patients require an appliance with the help of which they can walk without any difficulties and the appliance acts as an aid for the correct positioning of their joints. Presently Aluminum Alloy based calipers are used but still the patients urge for better comfort. The requirement apart from more strength and stiffness, durability at lesser cost, environment friendly and light weight. Composite material is one such material which provides lower weight to volume ratio, high strength and stiffness at lesser cost. The purpose of the authors is to compare the mechanical properties of presently used aluminum calipers with polymeric thermoset based matrix (Carbon cloth with epoxy) based on CAD tools. The comparison reveals that thermoset based matrix will provide the maximum strength and firmness when compared to presently used Aluminum based calipers and model designed on CAD tools. Hence, the usage of the composite material will help the researchers design orthotic calipers which will have higher strength at a lower weight.
作者: Vinayashree, R. Shobha
摘要: Aluminium composites are in predominant use due to their lower weight and high strength among the MMC’s. Aluminium 6061 is selected as matrix and E-glass fiber is selected as reinforcement. Fabrication of composite is done by stir casting method. Each fabrication carries the E-glass reinforcement content varied from 2% to 10%. The present article attempts to evaluate the mechanical properties of E-glass fibre reinforced composite and study the effect of reinforcement on the matrix alloy through mechanical properties. When compared to ascast mechanical properties the UTS has increased from 74.28 N/sq mm to 146.8 N/sq mm for a composite at 6% E-glass. The hardness of as-cast has also increased from 22 RHB to 43 RHB at 6% E-glass and the wear of composite has exhibited a decreasing tend with increase in reinforcement content along the sliding distance. The results are analyzed in certain depth in the current paper. The mechanical properties of composites have improved with the increase in the weigh percentage of glass fiber in the aluminium matrix.
作者: R.C. Mohan Kumar, C. Velmurugan
摘要: The blanking operation have several die design parameters which affect the quality of the blank and its productivity. The main input parameters are sheet thickness and the punch and die clearance and the dependent output parameters are tool life and the burr height. The selected values should be in optimal value. The optimum value is achieved by using the genetic algorithm. The genetic algorithm is an optimization process to find the better results as an output. Then the development of mathematical modeling by using the equations derived from the multiple regression analysis is performed. It is achieved by converting the linear equations into the matrix form and then solving it using mathematical relations. This output is compared with the genetic algorithm results, to get the better results.