scispace - formally typeset
Search or ask a question

Showing papers by "Indian Institute of Technology Kharagpur published in 1997"


Journal ArticleDOI
TL;DR: In this paper, the physical properties of sunflower seeds and kernels were evaluated as a function of moisture content and the mean equivalent diameter and sphericity of the seed were 5·39mm and 0·57 respectively.

379 citations


Journal ArticleDOI
TL;DR: In this article, three varieties of pearl millet seed, consisting of two hybrids GHB-30 and Bajra 28-15, and one Babapuri (traditional) variety, were graded, dried to 7·4% moisture content dry basis and properties of the major fraction were determined.

330 citations


Journal ArticleDOI
TL;DR: The extraction of fetal electrocardiogram (ECG) from the composite maternal ECG signal obtained from the abdominal lead is discussed, and the proposed method employs singular value decomposition (SVD) and analysis based on the singular value ratio (SVR) spectrum.
Abstract: The extraction of fetal electrocardiogram (ECG) from the composite maternal ECG signal obtained from the abdominal lead is discussed. The proposed method employs singular value decomposition (SVD) and analysis based on the singular value ratio (SVR) spectrum. The maternal ECG (M-ECG) and the fetal ECG (F-ECG) components are identified in terms of the SV-decomposed modes of the appropriately configured data matrices, and elimination of the M-ECG and determination of F-ECG are achieved through selective separation of the SV-decomposed components. The unique feature of the method is that only one composite maternal ECG signal is required to determine the P-ECG component. The method is numerically robust and computationally efficient.

304 citations


Journal ArticleDOI
19 Mar 1997-Langmuir
TL;DR: In this paper, it was shown that borohydride adsorbs on the surface of the silver particle and decreases the reduction potential of the particle so that it reacts rapidly with oxygen.
Abstract: Nanosize silver particles are formed in aqueous surfactant systems and have been found to be very reactive toward oxygen in the presence of borohydride. Purging of air (O2) or simple shaking leads to complete dissolution of silver particles, which is further regenerated on standing. Thus an oscillation between a yellow silver plasmon band and colorless solution is observed on periodic shaking. This oscillation continues as long as excess borohydride is present. Investigation shows that borohydride, which is a strong nucleophile, adsorbs on the surface of the silver particle and decreases the reduction potential of the silver particle so that it reacts rapidly with oxygen. Surfactant plays an extra role over particle stabilization. It removes the oxidized silver from the particle surface to the bulk and also retards the rate of reduction of AgI to Ag0.

261 citations


Journal ArticleDOI
TL;DR: In this article, the authors prove a simple intuitive multi-function generalization of the Leibnitz rule for high-order derivatives of products of two functions and use this to simplify this expression, thus giving a closed form solution for this problem.
Abstract: In many systems which are composed of components with exponentially distributed lifetimes, the system failure time can be expressed as a sum of exponentially distributed random variables. A previous paper mentions that there seems to be no convenient closed-form expression for all cases of this problem. This is because in one case the expression involves high-order derivatives of products of multiple functions. The authors prove a simple intuitive multi-function generalization of the Leibnitz rule for high-order derivatives of products of two functions and use this to simplify this expression, thus giving a closed form solution for this problem. They similarly simplify the state-occupancy probabilities in general Markov models.

243 citations


Journal ArticleDOI
TL;DR: In this article, a simplified model is developed to predict the characteristics of the material removal rate for varying input parameters with the objective of finding the possibility of enhancing the capability of the process.

136 citations


Journal ArticleDOI
TL;DR: Thresholding, the problem of pixel classification is attempted here using fuzzy clustering algorithms, using segmented regions are fuzzy subsets, with soft partitions characterizing the region boundaries.

134 citations


Journal ArticleDOI
TL;DR: Graft copolymers of starch, amylose, and amylopectin with polyacrylamide have been synthesized using a ceric-ion-initiated solution polymerization technique as mentioned in this paper.
Abstract: Graft copolymers of starch, amylose, and amylopectin with polyacrylamide have been synthesized using a ceric-ion-initiated solution polymerization technique. In the case of amylopectin-g-polyacrylamide (Ap-g-PAM), four graft copolymers have been synthesized with variation in the number and length of grafted polyacrylamide chains. The flocculation behavior has been studied in a 0.25% kaolin suspension. It has been found that among the three graft copolymers of the starch family, Ap-g-PAM is the best flocculating agent compared to starch-g-polyacrylamide (St-g-PAM) and amylose-g-polyacrylamide (Am-g-PAM). Among the series of Ap-g-PAM, the one with fewer but longer polyacrylamide chains has been found to be the most effective flocculant. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1721–1729, 1997

132 citations


Journal ArticleDOI
TL;DR: Lexicographic Goal Programming (LGP) has been used to find out weights from pairwise inconsistent interval judgment matrices and a number of properties and advantages of LGP as a weight determination technique have been explored.

119 citations


Journal ArticleDOI
TL;DR: In this paper, the reflection and refraction of thermoelastic waves at an interface of two semi-infinite media in contact with two relaxation times are studied following Green and Lindsay's theory.
Abstract: The reflection and refraction of thermoelastic waves at an interface of two semi-infinite media in contact with two relaxation times are studied following Green and Lindsay's theory. The analytical expressions for the partition of energy are carried out. The results for various values of the angle of incidence for the partition of energy are presented in the context of two different cases: (i) liquid-liquid and (ii) liquid-solid. The numerical results are represented graphically to aid the comparison with Lord and Shulman's theory in order to see the effect of the second relaxation time.

114 citations


Journal ArticleDOI
TL;DR: This paper uses a special type of non-linear (hyperbolic and exponential) membership functions to solve the multi-objective transportation problem and gives an optimal compromise solution.

Journal ArticleDOI
TL;DR: In this article, a new dicarboxylic acid receptor 1 having two pyridinc amide motifs built on a Troger's base spacer has been designed and synthesised.

Proceedings ArticleDOI
04 Jan 1997
TL;DR: This paper model the hardware software partitioning problem as a Constraint Satisfaction Problem (CSP), and presents a genetic algorithm based approach to solve the CSP in order to obtain the partitioning solution.
Abstract: Hardware software co-design is gaining importance with the advent of CAD for embedded systems. A key phase in such designs is partitioning the specification into hardware and software implementation sets. The problem being combinatorically explosive, several greedy search algorithms have been proposed for hardware software partitioning. In this paper, we model the hardware software partitioning problem as a Constraint Satisfaction Problem (CSP), and present a genetic algorithm based approach to solve the CSP in order to obtain the partitioning solution.

Proceedings ArticleDOI
22 Jun 1997
TL;DR: In this article, the authors show that sampled data models with stroboscopic sampling yield piecewise smooth maps and that most of the observed "anomalous" bifurcations fall into a class called "border collision bifurlcations".
Abstract: Nonstandard bifurcations have been reported in power electronic DC-DC converters. We show that sampled data models with stroboscopic sampling yield piecewise smooth maps and that most of the observed "anomalous" bifurcations fall into a class called "border collision bifurcations". We offer analytical explanation of the dynamics of three converter topologies (current mode controlled first order buck converter, current mode controlled boost converter, duty cycle controlled buck converter).

Journal ArticleDOI
TL;DR: In this article, the percolation limit for achieving high conductivity of conductive filler depends on the viscosity of the blend, and the higher the visco-sensitivity of the filler, the higher is the percoverage limit.
Abstract: Conductive rubber composites were derived from different blends of ethylene-propylene-diene monomer (EPDM) rubber and acrylonitrile butadiene rubber (NBR) containing acetylene black The electrical and mechanical properties of these composites were measured The percolation limit for achieving high conductivity of conductive filler depends on the viscosity of the blend The higher the viscosity, the higher is the percolation limit The conductivity rises with increasing temperature, and the activation energy of conduction increases with the decrease in the loading of conductive filler and percentage of NBR in the blend Electrical hysteresis and an electrical resistivity difference during the heating-cooling cycle are observed for these systems, which is mainly due to some kind of irreversible change occurring in the conductive networks during heating The mechanisms of conduction of these systems were discussed in the light of different theories It was found that the degree of reinforcement by acetylene black in blends compares with those in the pure components NBR and EPDM This is due to incompatibility of two elastomers in the blend

Journal ArticleDOI
TL;DR: In this article, the authors report the observation of coexisting attractors with fractal basin boundaries in the voltage mode controlled buck converter, and long chaotic transients resulting from chaotic saddles are observed for a large range of parameter values.
Abstract: We report the observation of coexisting attractors with fractal basin boundaries in the voltage mode controlled buck converter. Long chaotic transients resulting from chaotic saddles are observed for a large range of parameter values. These phenomena may have serious technological implications.

Journal ArticleDOI
TL;DR: In this article, the optimal design and operation of a heat recovery steam generator (HRSG) generating saturated steam for a combined gas and steam power cycle was investigated, and it was shown that an optimal saturation temperature exists for least irreversible operation of an existing HRSG with specified exhaust gas from the gas turbine of the "topping" cycle.

Journal ArticleDOI
TL;DR: In this paper, the influence of interaction between the two polymers on the mechanical and dynamic mechanical properties of the blends is analyzed in detail, and the results are interpreted on the basis of the formation of nylon-ACM graft copolymer at the interfaces.
Abstract: Nylon-6 and acrylate rubber (ACM) were melt blended in a Brabender Plasticorder at 220 °C and 40 rpm rotor speed. The reactive nature of the blend is reflected in the mixing torque behavior of the blends at different compositions. The solubility characteristics of the blends in formic acid solution gives an approximate idea of the amount of nylon-6 grafted onto ACM and vice-versa. A reaction mechanism is proposed based on the well known epoxy—amine and epoxy—acid reactions and is confirmed by infrared spectroscopic studies of the blends. The influence of interaction between the two polymers on the mechanical and the dynamic mechanical properties of the blends is analyzed in detail, and the results are interpreted on the basis of the formation of nylon—ACM graft copolymer at the interfaces. The dynamic mechanical thermal analysis (DMTA) reveals a two phase morphological structure, indicating incompatibility of the blend components. The grafting reaction results in dramatic increase in both the sto...

Journal ArticleDOI
TL;DR: In this article, a finite element (FEM) analysis of a rotor bearing system for flexural vibrations has been considered by including a shaft having a slant crack that has resulted from the fatigue of the shaft due to the torsional moment.

Journal ArticleDOI
TL;DR: In this paper, a quantum fluid density functional approach is adopted to study the time evolution of various reactivity parameters such as electronegativity, hardness, polarizability, and entropy associated with a collision process between a proton and a Be atom in its ground and excited electronic states.
Abstract: A quantum fluid density functional approach is adopted to study the time evolution of various reactivity parameters such as electronegativity, hardness, polarizability, and entropy associated with a collision process between a proton and a Be atom in its ground and excited electronic states. This collision process may be considered to be a model mimicking the actual chemical reaction between a Be atom and a proton to give rise to a BeH+ molecule. A favorable dynamical process involving a ground or an excited state is characterized by maximum hardness, minimum polarizability, and maximum entropy values.

Journal ArticleDOI
TL;DR: In this article, the growth of a high quality, step-graded lattice-relaxed SiGe buffer layer on a Si(100) substrate was investigated, and MOSFETs were fabricated on strained-Si grown on top of the above layer.
Abstract: The growth of a high quality, step-graded lattice-relaxed SiGe buffer layer on a Si(100) substrate is investigated. p -MOSFETs were fabricated on strained-Si grown on top of the above layer. Carrier confinement at the type-II strained-Si/SiGe buffer interface is observed clearly from the device transconductance and C - V measurements. At high vertical field, compared to bulk silicon, the channel mobility of the strained-Si device with x =0.18 is found to be about 40% and 200% higher at 300 K and 77 K respectively. Measurements on transconductance enhancement are also reported. Data at 77 K provide evidence of two channels and a large enhancement of mobility at high transverse field.

Journal ArticleDOI
TL;DR: In this paper, the authors present a model for predicting the reliability, availability, mean life time, and mean time to first failure of multistage degraded systems with partial repairs.

Journal ArticleDOI
TL;DR: In this paper, pure lanthanum aluminate (LaAlO3) powders were prepared by the evaporation of polyvinyl alcohol added to a mixed metal nitrate solution.

Journal ArticleDOI
TL;DR: In this paper, the Oyster Pleurotus variety of mushrooms were studied in the thin layer drying experimental equipment at each of the drying air temperatures of 45, 50 and 60°C with air velocities of 0.9 and 1.6 m/s.

Proceedings ArticleDOI
19 Oct 1997
TL;DR: It is proved that an O(nk/sup 1/3/) upper bound for planar k-sets is proved, the first considerable improvement on this bound after its early solutions approximately twenty seven years ago.
Abstract: We prove an O(nk/sup 1/3/) upper bound for planar k-sets. This is the first considerable improvement on this bound after its early solutions approximately twenty seven years ago. Our proof technique also applies to improve the current bounds on the combinatorial complexities of k-levels in arrangements of line segments, k convex polygons in the union of n lines, parametric minimum spanning trees and parametric matroids in general.

Journal ArticleDOI
01 Oct 1997
TL;DR: A unified computational framework is presented for facilitating edge detection both in untextured as well as textured two-dimensional (2-D) images using a complete set of difference operators which are easily configurable from a set of orthogonal polynomials.
Abstract: In this paper, a unified computational framework is presented for facilitating edge detection both in untextured as well as textured two-dimensional (2-D) images. The framework is based on a complete set of difference operators which are easily configurable from a set of orthogonal polynomials. The widely known Roberts, Sobel, Prewitt, and Marr's LOG edge operators can easily be represented in terms of these operators. For detection of untextured or textured edges, the proposed operators are employed to separate out the responses toward edge or texture and noise. Untextured edges are detected by maximizing signal-to-noise ratio (SNR) or identifying the zero crossings in the second directional derivatives. Textured edges are detected in two stages. First, the significance of responses toward texture is computed statistically in order to test the presence of microtexture and compute a local descriptor called "pronum" for its representation. Finally, a global descriptor for texture called "prospectrum" is obtained by observing the frequency of occurrence of pronums. The textured edges are detected at the second stage by applying the methods of detection of untextured edges on these prospectrums. The results are encouraging.

Journal ArticleDOI
TL;DR: A dinaphthyridine receptor was designed that efficiently binds to urea probably by six hydrogen bonds forming a chloroform soluble 1:1 complex and selectively extracts urea into chloromethyridine from its mixture with thiourea as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, surface modification of Kapton polyimide film (325 nm thick) by means of chromic acid and perchloric acid at different times and temperatures has been carried out.
Abstract: Surface modification of Kapton polyimide film (325 nm thick) by means of chromic acid and perchloric acid at different times and temperatures has been carried out. The contact angle of water decreased from 82 to 55° and the surface energy increased accordingly from 26 to 45 mJ/m2 with times of etching by chromic acid up to 45 min at 33°C. Etching at higher temperatures increased the surface energy. Chromic acid was more effective than perchloric acid. IR and XPS studies indicated multiple bonding and generation of poler groups on the surface. The peak at 1778 cm-1 due to the imide group decreased on acid etching. The O/C ratio increased and the N/C ratio decreased. The peel strength of the joint polyimide film/copper film/epoxy adhesive/aluminium sheet increased about two-fold on modification of the polyimide (PI) film at 33°C for 45 min, although the changes were marginal for the PI film/silicone rubber/PI film joint. The peel strength is a function of the time and temperature of etching.

Journal ArticleDOI
TL;DR: In this paper, the removal performance of phenol in a four-stage cross-flow laboratory-scale rotating biological contactor (RBC) reactor was investigated, where the impacts of major process and operating variables, viz. input phenol concentration ( PH i ), input phenoline loading ( PH l ), input hydraulic loading ( HL ), temperature of wastewater ( T ), and rotational speed of discs (ω) on the removal efficiency of the system were examined.

Journal ArticleDOI
TL;DR: A birds eye view of the continuous-time related aspects of the greater field of system identification is presented and some recent developments in the identification of linear systems and nonlinear systems are outlined.