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The suspension systems in automobile are required to provide optimum ride comfort and vehicle handling. As these two performance parameters are in contradiction with each other in automobiles fitted with regular passive suspension systems, various studies are being conducted to identify an alternative system that can optimise both the parameters. One such alternative is presented in the form of Magnetorheological (MR) damper, a most viable semiactive device. A MR damper comprises of MR fluid that consists of carbonyl iron powder and silicone oil added with additive. The characteristic of this damper has been established experimentally, which in turn is used to identify the parameters of spencer model for MR damper. Using spencer model of MR damper, at 5 different currents, viz.,0A, 0.25A, 0.5A, 0.75A, 1A, the half-car models of vehicle suspension system of a car and a multi axle truck are simulated for analysing the ride comfort and vehicle handling. The ride comfort and vehicle handling performance of each specific vehicle model with passive suspension system are compared with corresponding skyhook, ground hook and hybrid control semi-active suspension systems. The simulation and analysis are carried out using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

The aim of the paper is to investigate the effect of size of multiwalled carbon nanotubes (MWCNTs) as additives for dispersion in gear oil to improve the tribological properties. Since long pristine MWCNTs tend to form clusters compromising dispersion stability, they are mildly processed in a ball mill to shorten the length and stabilized with a surfactant before dispersing in lubricant. Investigations are made to assess the effect of ball milling on the size and structure of MWCNTs using electron microscopy and Raman spectroscopy. The long and shortened MWCNTs are dispersed in EP 140 gear oil in 0.5% weight. The stability of the dispersed multiwalled carbon nanotubes is evaluated using light scattering techniques. The antiwear, antifriction, and extreme pressure properties of test oils are evaluated on a four-ball wear tester. It is found that ball milling of MWCNTs has a strong effect on the stability and tribological properties of the lubricant. From Raman spectroscopy, it is found that ball milling time of up to 10 hours did not produce any defects on the surface of MWCNTs. The stability of the lubricant and the antiwear, antifriction, and extreme pressure properties have improved significantly with dispersion shortened MWCNTs. Ball milling for longer periods produces defects on the surface of MWCNTs reducing their advantage as oil additives. [ABSTRACT FROM AUTHOR]

Exposure of human body to vehicular vibrations in transit may lead to the human discomfort. Ride comfort is one of the major issues in design of automobiles. Magneto rheological (MR) dampers are emerging as most feasible solution for various applications in controlling vibrations. An MR damper is a semi-active device, which will offer the advantages of both active and passive suspension. In this study, the MR damper based semi-active suspension system for a car is analysed for ride comfort of 7 degrees of freedom model human body lumped mass, considering head, upper torso, lower torso and pelvis, seated over a seat of a quarter car model and is compared with that of similar system using passive damper. A MR damper is fabricated and is filled with MR fluid made of Carbonyl iron powder and Silicone oil added with additive. Modified Bouc-Wen Model developed by Spencer is used to model the behaviour of MR damper. All the parameters of this model are identified using data acquired from experiments conducted to characterise MR damper. Further, using the Spencer model of MR damper, the human body seated over quarter car is simulated by implementing a semi-active suspension system for analysing the resulting displacement and acceleration of the human body. The ride comfort performance of vehicle model with passive suspension system is compared with corresponding semi-active suspension system. The simulation and analysis are carried out using MATLAB/SIMULINK. [ABSTRACT FROM AUTHOR]

This study focused on the effect of drilling parameters such as helix angle, spindle speed and feed rate on surface roughness, flank wear and acceleration of drill vibration velocity. Using design of experiments, 18 experiments were conducted on AISI 304 steel with carbide twist drill bits. A laser Doppler vibrometer was used for online acquisition of cutter vibration data in the form of acousto optic emission signals. A fast Fourier transformer was used to convert the time domain signals into frequency domain. Response surface methodology was used to identify significant parameters in the analysis of surface roughness, flank wear and acceleration of drill vibration velocity. A multi response surface optimization technique was used to find out optimum drilling parameters. Helix angle of 25°, feed rate of 10 mm and spindle speed of 750 r/min were found to be optimum cutting parameters for minimization of surface roughness, flank wear and acceleration of vibration velocity. [ABSTRACT FROM AUTHOR]

Magnetorheological (MR) dampers are evolving as one of the most promising devices for semi-active vibration control of various dynamic systems. In this paper, the suspension system of a car using MR damper is analysed for 2DOF quarter car and 4DOF half car models and then compared with corresponding suspension system using passive damper for ride comfort and handling. Magnetorheological damper is fabricated using a MR fluid of Carbonyl iron powder and Silicone oil added with additive. Experiments are conducted to establish the behaviour of the MR damper and are used to validate Spencer model for MR damper. Further, using the validated Spencer model of MR damper, the quarter car and half car models of Vehicle Suspension system are simulated by implementing a semi-active suspension system for analysing the resulting displacement and acceleration in the car body. The ride comfort and vehicle handling performance of each specific vehicle model with passive suspension system are compared with corresponding semiactive suspension system. The simulation and analysis are carried out using MATLAB/SIMULINK. [ABSTRACT FROM AUTHOR]

In this article, effect of cutting parameters, namely, cutting speed, feed rate and tool nose radius, on the tool life was examined experimentally. The experiments were performed on boring of AISI 316 steel with cemented carbide tool inserts. Design of experiments was prepared, and eight experiments were performed with two levels of the cutting parameters. The effects of cutting parameters were analyzed by evaluating the amplitude of workpiece vibration, surface roughness and volume of metal removed. The experimental data were taken for evaluation of tool life for a flank wear of 0.6 mm in all the eight trials. A laser Doppler vibrometer was used for online data acquisition of workpiece vibration, and a high-speed fast Fourier transform analyzer was used to process the acousto-optic emission signals for the workpiece vibration. Taguchi, analysis of variance and regression analysis methods were used to identify significant cutting parameters affecting the workpiece vibrations, surface roughness and volume of metal removed. All selected analysis methods used in this study predicted similar cutting parameter. [ABSTRACT FROM AUTHOR]

The article presents a study that analyzes the flapwise bending vibration of functionally graded rotating concentrated mass. Discussion on the method of the study that examines the material properties of the mass through Rayleigh-Ritz method and dirac delta function is provided. The influence of the morphology, hub radius ratio, and angular speed of the flapwise bending natural frequencies of functionally graded beam is also investigated.

The increasing needs of the industry involved in development of components for aerospace and power sector demand the engineering community to develop new concepts and strategies to improve the functional requirements of structures and to enhance the strength of materials. This is particularly essential in the cases of rotating beams that are subjected to severe vibration under large pressure loadings, high rotating accelerations, centrifugal forces, geometric stiffening, etc. A theoretical investigation of the free vibration characteristics of rotating cantilever beams, made of a functionally-graded material (FGM) consisting of metal and alumina, is presented in this study. It was assumed that the material properties of the FGM beam were symmetric, but varied continuously in the thickness direction from the core at the mid section to the outer surfaces, according to a power-law relation. Equations of motion were derived from a modelling method, which employed the hybrid deformation variable. The natural frequencies were determined using the Rayleigh-Ritz method. The effect of parameters such as the power law index, the hub radius, and the rotational speed on the natural frequencies of functionally-graded rotating cantilever beams were examined through numerical studies and then compared with the numerical results reported in earlier works. [ABSTRACT FROM AUTHOR]

Background: In the backdrop of conflicting reports (some studies reported adverse outcomes of biomass fuel use whereas few studies reported absence of any association between adverse health effect and fuel use, may be due to presence of large number of confounding variables) on the respiratory health effects of biomass fuel use, this cross sectional survey was undertaken to understand the role of fuel use on pulmonary function. Method: This study was conducted in a village of western India involving 369 randomly selected adult subjects (165 male and 204 female). All the subjects were interviewed and were subjected to pulmonary function test. Analysis of covariance was performed to compare the levels of different pulmonary function test parameters in relation to different fuel use taking care of the role of possible confounding factors. Results: This study showed that biomass fuel use (especially wood) is an important factor for deterioration of pulmonary function (particularly in female). FEV1 (p < .05), FEV1 % (p < .01), PEFR (p < .05) and FEF25-75 (p < .01) values were significantly lower in biomass fuel using females than nonusers. Comparison of only biomass fuel use vs. only LPG (Liquefied Petroleum Gas) use and only wood vs. only LPG use has showed that LPG is a safer fuel so far as deterioration of pulmonary function is concerned. This study observes some deterioration of pulmonary function in the male subjects also, who came from biomass fuel using families. Conclusion: This study concluded that traditional biomass fuels like wood have adverse effects on pulmonary function. [ABSTRACT FROM AUTHOR]

An abstract of the article "Research Trends in a Premier Institute Based on Annual Reports," by Ketki Bhatia, N. Mohan Rao and H.N. Saiyed is presented.

Devadaru compound was shown to be beneficial in Tamak Swasa (bronchial asthma). Clinical findings revealed higher percentage of relief in cardinal and general symptoms with decrement in the pulse rate and in the respiration rate. A significant linear increase in PEFR value was observed before and after treatment and an increase in FEV1 values measured in Group I subjects. There was relief of all symptoms in a significant number of patients. Occurrence of relief was observed only among patients who suffer less than 10 years duration with Tamak Swasa and among those the frequency of attacks of Tamak Swasa was at fortnightly or monthly intervals. Antispasmodic activity of Devadaru Compound (DC) on acetylcholine (Ach) induced contractions using rat ileum preparation was studied. The results demonstrated that DC inhibits Ach-induced contractions significantly and bears a dose-response relationship. This suggests that DC has got anti-spasmodic activity and corroborates the clinical findings. The clinical findings and experimental studies show that DC is of significant use in the treatment of Tamak Swasa (Bronchial Asthma) and superior to the standard and placebo therapy.