NISCAIR Online Periodicals Repository Collection: IJEMS Vol.13(2) [April 2006]

On imaging metal grains at high temperature: Laser light scattering microscopy

Title: On imaging metal grains at high temperature: Laser light scattering microscopy

Authors: Prasad, P B V; Shashikanth, P B

Abstract: A simple device has been developed to meet the need of a base that is free from thermal expansion and is required in certain hot-stage microscopy studies. Further, images of sub-millimeter sized metal grains at high temperatures are noticed to under go vibration-like motion. In order to achieve stabilization of images, a unit called beam path cooler has been devised and its effect is examined.

Page(s): 162-166

Synthesis and physico-chemical study of halogenated aromatic cardo polysulfonates

Title: Synthesis and physico-chemical study of halogenated aromatic cardo polysulfonates

Authors: Manwar, B G; Kavthia, S H; Mehta, N M; Parsania, P H

Abstract: Poly(R, R′, 4, 4′-cyclohexylidene diphenylene-2, 4-toluene disulfonate) (PS-3: R=R′=C1 and PS-4: R=CH₃and R′=C1) have been synthesized by interfacial polycondensation technique by using water-chloroform (4:1 v/v) as an interphase, alkali (0.12 mol) as an acid acceptor and cetyl trimethyl ammonium bromide as an emulsifier. The reaction time and temperature are 3½ h and 0ºC, respectively. The structure of PS-3 and PS-4 are supported by IR and NMR spectral data. The intrinsic viscosities of the said polymers are determined in different solvents at three different temperatures 30, 35 and 40ºC. The calculated and experimental (floatation method) densities are found in good agreement with small fractional free volume. PS-3 and PS-4 possess excellent resistance to hydrolytic attack against water, acids, alkalis and salt, moderate tensile strength (15.6-17.0 N/mm²), excellent volume resistivity (1.1 to 3.9 10¹⁵ Ω cm), high electric strength (33.9-32.9 kV/mm) and low dielectric constant (1.36), good thermal stability (360ºC and 340ºC) and high T_g (143.5^oCand 134.3ºC). DSC and DTA endo/exothermic transitions have supported physico-chemical changes. No change in tensile strength is observed but volume resistivity has increased 1.5 to 54.2 times, while electric strength has increased 2.5 to 3.5 times upon introducing methyl and chlorine groups alone or in combination. The improvement in volume resistivity and dielectric constant is due to cancellation of partial charges present on the polymer molecules.

Page(s): 155-161

Inflation pressure effect on whole tyre hysteresis ratio and radial spring constant

Title: Inflation pressure effect on whole tyre hysteresis ratio and radial spring constant

Authors: Pillai, Padmanabha S

Abstract: The basic equation for rolling loss R in terms of the whole tyre hysteresis ratio h is modified by incorporating tyre radial stiffness K and rewritten as R = L² (h/K). (w/A), where w and A are footprint dimensions. Tyre inflation pressure p influences the magnitude of h and K. The primary objective of the present study is to obtain quantitative expressions relating h versus p and K versus p. Three P195/75R14 size radial tyres are selected for the present investigation. The h and K values of these tyres are measured as a function of p and analyzed by invoking two limiting structural terms, viz., structural hysteresis ratio h(0) and structural radial stiffness K(0). The empirical relation between h and p is found to be inversely related as h = k (1/p^x). The h(0) values are about 0.38, 0.27 and 0.28 for tyres 1, 2 and 3. The hysteresis ratio reduction factor h(f) is normalized with respect to h(0) and is found to be about 78% of h(0) value of the respective tyre. The K term is partitioned into structural stiffness K(0) and inflation pressure stiffness K(). The K(0) values are about 60, 25 and 67 N/mm respectively. The K versus p relation can be expressed as K = K(0) + m.p. = K(0) + K(). The pressure stiffness K() is directly proportional to p as K() = 0.56.p. These empirical equations with experimentally determined fitting coefficients k, ϰ and m for the three P195/75R14 tyres are presented. This study indicates that the tyre size primarily controls the magnitude in reduction of h, through h(f), and the increase in K, through K(), with p. The total tyre load of 5337 N is separated into structural load and pressure load; the former load has a direct relationship with R while the latter has an inverse relation. This is a new analytical approach relating tyre load and rolling loss.

Page(s): 110-116

A decision fusion algorithm for tool condition monitoring in drilling using Hidden Markov Model (HMM)

Title: A decision fusion algorithm for tool condition monitoring in drilling using Hidden Markov Model (HMM)

Authors: Natarajan, U; Arun, P; Periasamy, V M

Abstract: In today’s world, the leading industries are very much concerned about reducing down-time and increasing the productivity as well as the quality. To increase the product quality, the tool should have good performance. Drilling process is widely used in the manufacturing operations in all the manufacturing industries. In this study, two Hidden Markov Models (HMM) such as bar-graph method and the multiple modeling methods have been used to determine the tool wear states in drilling operations. Cutting speed, feed rate, drill diameter and torque are taken as input parameters for the HMM bar-graph method. Cutting speed, feed rate, drill diameter, thrust force and feed-motor power are taken as input parameters for the HMM multiple modeling methods. In order to increase the reliability of these outputs, a Decision Fusion Center Algorithm (DFCA) is proposed which combines the outputs of the individual methods to make a global decision about the wear status of the drill tool.

Page(s): 103-109