CFD Modeling and Optimization of Magneto-rheological Abrasive Flow Finishing (MRAFF) Process

A modern nano finishing technique called magnetorheological abrasive flow finishing (MRAFF), which is simply a combined hybrid form of abrasive flow machining (AFM) process and magnetorheological finishing (MRF) process, has been designed for micro finishing of parts even with difficult geometry for a broad range of industrial purposes. In the present work, a model for the prediction of removal of material and surface roughness has been estimated. An effort has been made to study the flow passing through the stainless steel workpiece by CFD modeling in ANSYS 15.0 FLUENT. By assuming the medium as Bingham plastic various parameters affecting the surface roughness has been calculated. Also a theoretical calculation is made for the model if no magnetic field is applied and then comparative study of the two models is proposed. An optimization of the process has also been carried out. With the help of SN Ratio plot and Means plot optimized value of input parameters has been found out to achieve better surface finish

CFD Modeling and Optimization of Magneto-rheological Abrasive Flow Finishing (MRAFF) Process

A modern nano finishing technique called magnetorheological abrasive flow finishing (MRAFF), which is simply a combined hybrid form of abrasive flow machining (AFM) process and magnetorheological finishing (MRF) process, has been designed for micro finishing of parts even with difficult geometry for a broad range of industrial purposes. In the present work, a model for the prediction of removal of material and surface roughness has been estimated. An effort has been made to study the flow passing through the stainless steel workpiece by CFD modeling in ANSYS 15.0 FLUENT. By assuming the medium as Bingham plastic various parameters affecting the surface roughness has been calculated. Also a theoretical calculation is made for the model if no magnetic field is applied and then comparative study of the two models is proposed. An optimization of the process has also been carried out. With the help of SN Ratio plot and Means plot optimized value of input parameters has been found out to achieve better surface finish

Correspondence of butterfly and host plant diversity: Foundation for habitat restoration and conservation

At a spatial scale, the diversity of butterflies varies with numerous factors including the availability of the host plant species. In parity with this proposition, the correspondence of diversity of butterfly and plant in the background of the urban–rural gradient was evaluated using Kolkata, India, as a model study area. The results reveal significant positive correlation between the diversity of butterflies and the plants, with the different values for the suburban, rural, and urban areas. Identification of the butterfly loads for the plants in the respective areas can be useful in enhancing the conservation of the butterflies through enhanced plantation of the concerned plant species. Alternatively, the disclosure of the generalist and specialist pattern of the plant species preference by the butterflies may be useful in enhancing the population of the respective species in the concerned areas. The conservation strategy for butterfly species may be refined through the use of both or any one of the quantitative assessment of the butterfly–plant links in the urban–rural gradient in Kolkata, India, and similar places in the world

Stabilizing Gain Selection of Networked Variable Gain Controller to Maximize Robustness Using Particle Swarm Optimization

Networked Control Systems (NCSs) are often associated with problems like random data losses which might lead to system instability. This paper proposes a method based on the use of variable controller gains to achieve maximum parametric robustness of the plant controlled over a network. Stability using variable controller gains under data loss conditions is analyzed using a suitable Linear Matrix Inequality (LMI) formulation. Also, a Particle Swarm Optimization (PSO) based technique is used to maximize parametric robustness of the plant.Comment: 6 pages, 6 figure

Noise levels at traffic intersections and awareness of noise pollution among traffic policemen and automobile drivers

Introduction: Noise pollution is an important health hazard in modern times and traffic policemen and automobile drivers are exposed to unregulated vehicular noise. This study aims to estimate the exposure levels from traffic noise for traffic policemen and automobile drivers and assess their awareness regarding noise pollution and the use of noise prevention measures. Methods: An analytical cross-sectional study was carried out comprising the exposed and the control group with 121 people in each group. Sound level estimation was carried out across 20 traffic intersections in the city at various times to assess the noise levels. All the participants were administered a pretested questionnaire to assess their awareness regarding noise pollution and as well as the use of noise prevention strategies.  The chi-square test was used to estimate the difference between the two groups. P <0.05 was considered statistically significant. Results: The noise levels at traffic intersections are above the permitted and acceptable limits. The mean ±SD of sound levels at traffic points range from 76.7±5.8 dB to 83.4±6.3 dB across various traffic intersections. The mean noise level at the traffic intersection was in the high-risk category (81-86dB) in 25% of traffic points while 75% of traffic points had noise levels in the moderate risk (76 - 81dB) category. 88% of the exposed group and 95% of the control group considered noise to be a form of pollution even though they were not aware of all the harmful effects. In practice, only 34% of study participants used some form of hearing protection measures, even though the majority were aware of the need to do so. Conclusion: The noise levels at traffic intersections are high. This is coupled with a lack of adequate use of hearing protective devices which can be detrimental to the inner ear. Frequent awareness programs are necessary to educate the occupationally exposed personnel on proper noise prevention strategies. At the same, time it is necessary to take decisive measures to curb the ever-increasing menace of occupational noise exposure