C. Kavitha

Bio: C. Kavitha is an academic researcher from Sathyabama University. The author has contributed to research in topics: Fuzzy logic & Adaptive neuro fuzzy inference system. The author has an hindex of 5, co-authored 25 publications receiving 83 citations. Previous affiliations of C. Kavitha include Vikram Sarabhai Space Centre & Kumaraguru College of Technology.

Active camber and toe control strategy for the double wishbone suspension system

Abstract: The present research work proposes a method for improving handling characteristics of the vehicle by controlling camber and toe angle using double wishbone suspension arms in an adaptive manner. This is accomplished by two telescopic arms with actuators which changes camber and toe angle of the wheel dynamically to deliver best possible traction and manoeuvrability. Active suspension controllers are employed to trigger the actuators based on the camber and toe angle from sensors for reducing the existing error. Hence the arms are driven by the actuators in a closed loop feedback manner with help of a separate PID controller. A quarter car physical models with double wishbone suspension is modelled in SolidWorks and simulated using MATLAB for analysis. The simulation result shows an improvement of 58% in camber and 96% improvement of toe characteristics. A prototype of the proposed system is developed and subjected to the same test as the simulation system. The prototype achieved an improvement of 46.34% in camber and a 93.35% in the toe variation of the active system over the passive system. Further, the prototype was able to achieve 89% of camber reduction and 45% of toe reduction with respect to the simulation.

A New Approach to Spindle Radial Error Evaluation Using a Machine Vision System

Abstract: The spindle rotational accuracy is one of the important issues in a machine tool which affects the surface topography and dimensional accuracy of a workpiece. This paper presents a machine-vision-based approach to radial error measurement of a lathe spindle using a CMOS camera and a PC-based image processing system. In the present work, a precisely machined cylindrical master is mounted on the spindle as a datum surface and variations of its position are captured using the camera for evaluating runout of the spindle. The Circular Hough Transform (CHT) is used to detect variations of the centre position of the master cylinder during spindle rotation at subpixel level from a sequence of images. Radial error values of the spindle are evaluated using the Fourier series analysis of the centre position of the master cylinder calculated with the least squares curve fitting technique. The experiments have been carried out on a lathe at different operating speeds and the spindle radial error estimation results are presented. The proposed method provides a simpler approach to on-machine estimation of the spindle radial error in machine tools.

Effect of surface mechanical attrition treatment (SMAT) on zinc phosphating of steel

Abstract: The effects of surface mechanical attrition treatment (SMAT) of EN8 steel on the growth of phosphate coatings, morphological features and corrosion resistance of the resultant coatings have been studied. SMAT enabled the formation of a uniform surface profile although the average surface roughness is increased after treatment. SMAT increased the extent of metal dissolution and the rate of growth of phosphate coating. In spite of the similarity in phase composition, the phosphate crystallite size is relatively high for samples treated by SMAT. Compared to the untreated one, a cathodic shift in Ecorr with a corresponding decrease in icorr is observed for SMAT treated EN8 steel after phosphating. For all tested samples, zinc phosphate coatings deposited on EN8 steel after SMAT using 8 mm O balls for 30 min offers the highest corrosion resistance. The increase in surface roughness by SMAT is partly compensated by the expected improvement in corrosion resistance.

Photocatalytic degradation of disperse azo dyes in textile wastewater using green zinc oxide nanoparticles synthesized in plant extract: A critical review

Abstract: Textile wastewater comprises a complex mixture of chemical substances and dyes such as disperse dyes which have a high potential as carcinogenic, mutagenic, and teratogenic. Textile wastewater effluent contributes 20% of the water pollution with a high contribution to environmental contamination, where about 50,000 tons/year of dyes are dumped into the environment. The advanced oxidation processes (AOPs), which includes photocatalytic degradation (PD) using nanophotocatalysts, is a rising technology causing in completing the mineralization of the dyes, compared to traditional treatment techniques such as the absorption method, which transfers the pollutants to other stages. Photolysis is capable of partially degrading 50 to 80% of micro-pollutants like dyes using nanophotocatalysts. The literature indicates that about 70 to 80% of studies use photocatalysis using ZnO/TiO2 as a photocatalyst in wastewater treatment. However, the photocatalysts used have limited potential for removing dyes from textile wastewater. Thus, it is urgent to improve the ZnO NPs synthesis to maximize the PD efficiency to degrading textile wastewater dyes. The present review focuses on exploring the efficiency and mechanism of the photodegradation of textile wastewater dyes using zinc oxide nanoparticles (ZnO NPs) synthesized in the plant extract. The highest photolysis efficiency was found at low dye concentrations and pH to improve the initial operating parameters. Photolysis increases with increasing photocatalysis in the surface area and with an optimum amount of photocatalyst. Furthermore, appropriate photoirradiation is also necessary to conduct the photocatalytic process at room temperature.

Surface Modifications of Poly(Ether Ether Ketone) via Polymerization Methods-Current Status and Future Prospects.

Abstract: Surface modification of poly(ether ether ketone) (PEEK) aimed at applying it as a bone implant material aroused the unflagging interest of the research community. In view of the development of implantology and the growing demand for new biomaterials, increasing biocompatibility and improving osseointegration are becoming the primary goals of PEEK surface modifications. The main aim of this review is to summarize the use of polymerization methods and various monomers applied for surface modification of PEEK to increase its bioactivity, which is a critical factor for successful applications of biomedical materials. In addition, the future directions of PEEK surface modifications are suggested, pointing to low-ppm surface-initiated atom transfer radical polymerization (SI-ATRP) as a method with unexplored capacity for flat surface modifications.