Developments in non-conventional machining for sustainable production - a state of art review

Abstract

EXAMINING THE IMPACT OF STRUCTURAL BREAKS ON PRICE DISCOVERY EFFICIENCY: EVIDENCE FROM THE INDIAN EQUITY FUTURES MARKET

The current study aims to examine the impact of structural breaks on price discovery efficiency of Indian equity futures market. Global financial crisis, change of Government, demonetization and COVID-19 are identified as significant events. Data is divided into sub-samples of pre and post event period to study the impact of these events on price discovery efficiency of the Indian equity futures market. Unit root test is used to check stationarity of data. Granger causality test, Johansen’s cointegration test and Vector error correction methodology (VECM) are used for analysis. During full sample period, it is observed that there is a significant bi-directional causality between cash and futures markets and cash market leads futures market in price discovery. In addition, global financial crisis triggered volatility in Indian equity futures market, which reduced its price discovery efficiency, whereas, after change in Government, bidirectional transmission of information restored between cash market and futures market. Furthermore, futures market played a leading role in absorbing volatility triggered by demonetization. COVID-19 did not significantly affect price discovery efficiency of Indian equity futures market

Awareness of Discovery Tool among Library Professionals: A Survey

The aim of this study to find out the awareness, use of discovery tool among library professionals. The study preferred the survey method and a structured questionnaire tool for gathering data. Finding of the study that library professionals need to aware of the new technology related to the library activities using federated searching, discovery tool, next-generation catalog and web-scale discovery tool. In this paper analysed and found that the awareness of ICT and knowledge management required to the library professionals. The library professionals (more than 98%) aware of the library software terminology and they do not know the other new terminology, i.e. Discovery Tool, Federated Search, Facet Search, Web-Scale Discovery and Next-Generation Catalog

Effect of Addition of Al to Sn-Zn Solder Alloys

Conventional solders consist of Lead, that was found to be toxic and carcinogenic. Hence, restrictions were put on its use by the industrially developed nations. To counter the use of Lead, active research was pursued into the development of Lead-free solders. In our project, we fabricated alloys of composition 3:15:82, 7:43:50 and 10:80:10 (in terms of Aluminium, Zinc and Tin respectively), under furnace cooled and air-cooled conditions. The use of Aluminium was made so as to increase the resistance of the solder to atmospheric corrosion, and also to improve the wettability of the samples. Optical micrographs were obtained for each sample so as to analyze their microstructures. For a deeper understanding, SEM images of each sample were obtained, and EDX analysis was performed side-by-side so as to understand the elemental composition of different phases present in the sample. DSC and TG tests were conducted to determine the melting point of the solder alloy, and the weight gain in the alloy on oxidation respectively. The wettability of each sample was also analyzed. We recorded and plotted down the trends in each case. We then tried to evaluate the most effective solder composition on the basis of the above tests. The near-eutectic composition was considered so as to avoid the formation of a pasty phase that will cause disruption in electrical work

AN INVESTIGATION ON MEAN ROUGHNESS DEPTH AND MATERIAL EROSION SPEED DURING MANUFACTURING OF STAINLESS-STEEL MINIATURE RATCHET GEARS BY WIRE-EDM

This paper presents the results of an investigation conducted on wire electric discharge machining (wire-EDM) of miniature ratchet gears. Effects of three important process parameters spark duration, ‘Ton’, spark-off-duration ‘Toff’, and wire tension ‘WT’ on surface quality, i.e., mean roughness depth ‘Rz’ and productivity, i.e., material erosion speed ‘MES’, have been investigated by conducting seventeen experimental trials. Both Ton and Toff have been identified as the significant parameters. Further, an optimization of wire-EDM parameters resulted in simultaneously best compromise values of Rz 5.30 µm and MES 6.75 mm/min and is achieved the following cutting regime: Ton 1.5 µs, Toff 42.5 µs, and WT 1500 g. At the end, surface quality study has been conducted to evaluate the tribological fitness of the miniature ratchet gear machined at optimum combination of wire-EDM parameter values. It was investigated that the generation of uniform and shallow craters on the flank surfaces of ratchet gear machined at optimum values of parameters, imparted smoother bearing area curve and lower coefficient of friction. The profile and flank surface of the ratchet gear also found free from cracks, burrs, and dirt

Predictive modelling and parametric optimization of minimum quantity lubrication assisted hobbing process

Abstract: This paper focuses on parametric analysis, modelling, and parametric optimization of minimum quantity lubrication assisted hobbing (MQLAH) using environment friendly lubricant for manufacturing superior quality spur gears. Influences of hob cutter speed, axial feed, lubricant flow rate, air pressure and nozzle angle on the deviations in total profile, total lead, total pitch and radial runout and flank surface roughness parameters were studied by conducting 46 experiments using Box-Behnken method of response surface methodology. Results revealed that effect of air pressure is negligible but other parameters have significant impact on the considered responses. Back propagation neural network (BPNN) model was developed to predict microgeometry deviations and flank surface roughness values of the MQLAH manufactured spur gears. The BPNN predicted results found to be very closely agreeing with the corresponding experimental results with mean square error as 0.0063. Real-coded genetic algorithm (RCGA) was used for parametric optimization of MQLAH process to simultaneous minimization of microgeometry deviations and flank surface roughness. Standardized values of the optimized parameters were used to conduct confirmation experiment whose results had very good closeness with RCGA computed and BPNN predicted values and produced spur gear of superior quality. This study proves MQLAH to be a potential sustainable replacement of conventional flood lubrication assisted hobbing for manufacturing cylindrical gears of better quality

Investigation on manufacturing of small-sized stepped rotor wheel by engraving milling process

This study aims to explore the potential of the engraving milling process to manufacture 3D structures and layouts like rotor wheels. An experimental study was carried out to manufacture a stepped rotor wheel from EN8 steel blank using a computer numeric control (CNC) engraving milling machine tool. The impact of variable parameters, namely rotational speed (SR), feed (f), and plunge feed (Pf), on maximum roughness depth (Rt) and material removal rate (MRR) was determined through a total of fourteen tests, each with two replications based on Box-Behnken design (BBD) of the response surface methodology (RSM). The best variable combination was found using desirability functional analysis (DFA) with goals of minimizing Rt and maximizing the MRR. The best values achieved at the optimal combination of variable parameters were 2.95 µm as Rt and 43.45 mm³/min as MRR. Micrographs of the rotor wheel blades and cutting tool supported the findings

Indian Diabetes Risk Score (IDRS) as a strong predictor of diabetes mellitus: A cross sectional study among urban population of Jhalawar, Rajasthan

Introduction: The patients with Type 2 diabetes Mellitus may often remain asymptomatic for a longer period of time. The Indian Diabetes Risk Score (IDRS), a simple screening tool for prediction of undiagnosed diabetes. Objective: Validation of IDRS with standard test for type 2 diabetes among urban population of Jhalawar, Rajasthan. Material and Methods: A Community based Cross-sectional study was carried out in urban field practice area of Department of Community Medicine, Jhalawar Medical College, Jhalawar, Rajasthan. The study was conducted using a two-stage sampling design. A predesigned, pretested proforma and Indian Diabetes Risk Score (IDRS) sheet was used to collect data from the study participants. The IDRS is based on four parameters: age, family history of diabetes, waist circumference and physical inactivity. Data was collected using the World Health Organization stepwise approach to surveillance (STEPS). Results: Among 450 participants, 12.7% participants were in low risk, 59.1% were in moderate risk and 28.2% were in high risk of developing diabetes according to IDRS score. IDRS score of ?60 turned out to be the best cut point for identifying undiagnosed diabetes with sensitivity 92.3% and specificity 82.6%. Positive Predictive value and Negative Predictive value were 47.3% and 98.5% respectively. Conclusion: Association of IDRS was found significant with diabetes. IDRS score of ?60 turned out to be the best cut point for identifying undiagnosed diabetes. IDRS is found valid screening tool for early detection of Diabetes