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Tool Wear, Chip formation and Workpiece surface issues in CBN Hard Turning: A Review
Manu Dogra,Vishal S Sharma,Anish Sachdeva,Narinder Mohan Suri,Jasminder Singh Dureja4 한국정밀공학회 2010 International Journal of Precision Engineering and Vol. No.
Steel parts that carry critical loads in everything from automotive drive trains and jet engines to industrial bearings and metal-forming machinery are normally produced by a series of processes, including time-consuming and costly grinding and polishing operations. Due to the advent of super-hard materials such as polycrystalline cubic boron nitride (PCBN) cutting tools and improved machine tool designs, hard turning has become an attractive alternative to grinding for steel parts. The potential of hard turning to eliminate the costs associated with additional finishing processes in conventional machining is appealing to industry. The objective of this paper,is to survey the recent research progress in hard turning with CBN tools in regard of tool wear, surface issues and chip formation. A significant pool of CBN turning studies has been surveyed in an attempt to achieve better understanding of tool wear, chip formation, surface finish, white layer formation, micro-hardness variation and residual stress on the basis of varying CBN content, binder, tool edge geometry, cooling methods and cutting parameters. Further important modeling techniques based on finite element, soft computing and other mathematical approaches used in CBN turning are reviewed. In conclusion, a summary of the CBN turning and modeling techniques is outlined and the scope of future work is presented.
Manu Varghese Thottackkad,Rajendrakumar Krishnan Perikinalil,Prabhakaran Nair Kumarapillai 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
Considering the environmental problems created by mineral based lubricants, exploring the possibility of the use of vegetable base oils as automobile lubricants has been a growing worldwide trend. In the present study, analysis of coconut oil as a lubricant has been carried out in the perspective of its tribological behaviour using a pin-on-disc tribometer. Copper oxide nanoparticles are added to the oil on weight-percentage basis, the variation of its friction-reduction and antiwear properties are analysed. At an optimum concentration of nanoparticles, the coefficient of friction and the specific wear rate are found to be the lowest. Viscosity of oil is also seen to increase by an increase of concentration of nanoparticles. Flash-point remains constant while the fire-point increases as the nanoparticle concentration is increased. From dispersion analysis it is seen that the nano oil is not suitable enough for long stationary applications. Surface structure of the worn surfaces obtained by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) shows that the optimum concentration of nanoparticles in this lubricant causes the roughness of the worn pin surface to reduce to a low value after sliding. Wear scar obtained in the presence of nano oil is smoother compared to that with bare coconut oil. When the level of nanoparticles increases above the optimum level, friction coefficient and wear rate are seen to increase.
Manu Srivathsa,Pawan Kumar,Manipal Institute of Technology, Manipal Academy of Higher Education,U. K. Goutam 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.2
This research work focuses on the influence of Neodymium (Nd) doping (0–10 at.%) on the structural, optical, electrical,and photo-response properties of Zinc Oxide thin films deposited on glass substrates by cost-effective spray pyrolysis technique. For all the deposited films, the X-ray diffraction peaks matched the hexagonal wurtzite structure of ZnO with themaximum intensity along the (1 0 1) plane. Using XRD data, the crystallite size, dislocation density, and micro-strain of thefilms were estimated. Compared to other films, Zn0.96Nd0.04Ofilm exhibited higher crystallinity ~ 18 nm. At higher dopingconcentrations, a fibrous-granular mixed structure was observed. Above 80 percentage of transparency in the visible regionand bandgap of 3.42 eV was observed for the Zn0.96Nd0.04Ofilm. The decrease in Urbach energy with increase in the dopingconcentration indicated the improvement in crystallinity. The peaks related to band edge emission, zinc, and oxygen-relateddefects were observed in the photoluminescence analysis also increased band edge emission and lesser defects were observedin the Zn0.96Nd0.04Ofilm. The highest charge carrier concentration ~ 1.7 × 1017cm−3 and mobility ~ 62.8 cm2/Vs were noticedin of Zn0.96Nd0.04Ofilm. When exposed to UV light, Zn0.96Nd0.04Ofilm exhibited the maximum photocurrent ~ 10−4 A. Hencethe Zn0.96Nd0.04Ofilm can be used as a UV photodetector.
Manu Kumar,Chakra Dhar Tripathi,Veena Verma,Biswa Mohan Padhy,Girish Gulab Meshram,B Abhilash 대한신경정신의학회 2016 PSYCHIATRY INVESTIGATION Vol.13 No.4
ObjectiveaaTo determine the predictive validity of some of the commonly employed models of mania and depression using standard drugs i.e. lithium (70 mg/kg) and lamotrigine (5 mg/kg) in male Wistar rats. MethodsaaThe depression facet of bipolar disorder was evaluated using forced swim test, tail suspension test, and chronic mild stress test. The models used to evaluate the mania facet of bipolar disorder were isolation-induced aggression test, saccharine preference test, and morphine-sensitized hyperlocomotion test. ResultsaaThe immobility time was significantly (p<0.05) reduced by lamotrigine in the tail suspension test and the forced swim test, while lithium caused significant (p<0.05) reduction only in the tail suspension test. Rats exposed to chronic mild stress showed the maximal increment of 1% sucrose consumption at the 3rd week of treatment in both the lithium (p<0.001) and lamotrigine (p<0.01) groups. In the isolation-induced aggression test, the aggressive behaviour of rats was significantly reduced by both lithium [approach (p<0.001), attack (p<0.01), and bite (p<0.01)] and lamotrigine [approach (p<0.001), and attack (p<0.05)]. Neither of the drugs were effective in the saccharine preference test. Only lithium was able to significantly (p<0.05) reduce the crossing parameter in morphine-sensitized rats. ConclusionaaOur study identifies the chronic mild stress test and isolation-induced aggression test of having the highest predictive validity in the depression and mania facets of bipolar disorder, respectively, and should be a part of a battery of tests used to evaluate novel mood stabilizers.