Showing papers by "Indian Institute of Technology Madras published in 1970"
TL;DR: In this paper, a mechanism for the surface reaction of acetic acid on chromia is suggested and discussed based on a comparison of the energies of activation and the previously established fact that both the dehydration and dehydrogenation activity of chromia are required for the ketonization reaction.
37 citations
TL;DR: In this paper, a chain structure containing MoO 6 octahedra linked through oxygen is proposed for the complex oxalates on the basis of i.r. absorption spectra.
27 citations
TL;DR: In this paper, the analysis of instability of a gas-liquid interface when accelerated in a direction perpendicular to its plane has been found to be a singular perturbation problem, solved by the method of succesive approximations.
Abstract: The analysis of instability of a gas-liquid interface when accelerated in a direction perpendicular to its plane has been found to be a singular perturbation problem. The problem is solved by the method of succesive approximations. The results which are determined to the third order, differ qualitatively and quantitatively from those of the linear theory. Surfactension and curvature are included in the analysis. The growth factor of the interface is found to depend not only on the wave number but also on the amplitude of the initial disturbance. The results are in good agreement with the experiments.
23 citations
21 citations
TL;DR: In this paper, a linear dynamical system can be reduced to a simplified model by dividing the total time of response into a number of smaller intervals and retaining only those eigenvalues of the system which have a dominant effect on the transient response during the time interval of interest.
Abstract: A method is proposed by which a large linear dynamical system can be reduced to a number of simplified models by dividing the total time of response into a number of smaller intervals. This reduction is based on retaining only those eigenvalues of the system which have a dominant effect on the transient response during the time interval of interest.
19 citations
TL;DR: In this article, a non-linear theory of periodic gravity waves in an incompressible inviscid liquid is presented and the problem which is found to be a singular perturbation problem is treated accordingly with considerable ease.
Abstract: A non-linear theory of periodic gravity waves in an incompressible inviscid liquid is presented. The problem which is found to be a singular perturbation problem is treated accordingly with considerable ease. Results for frequency, surface profile and potential function are calculated up to third order as series in powers of a parameter which is the ratio of the amplitude to wavelength. Unlike the linear theory, in this third-order theory, the frequency is found to depend on the amplitude also and decreases with increasing amplitude. The results agree with those obtained earlier by a complicated and labourious method and confirmed by experiments.
17 citations
TL;DR: In the pH range 2.65-5.65 there is a small but reproducible loss in oxidative titre which is maximal at pH 4.7, which is ascribed to side-reactions occurring during partial disproportionation of monochloramine-T to dichloramine and p-toluenesulphonamide.
17 citations
TL;DR: In this article, the Born model was used to calculate the room temperature cohesive energies of NH4Cl and NH4Br and the computed values are respectively 155·0 and 148·2 kcal/mole.
15 citations
TL;DR: In this article, a procedure for the design of optimal feedback control for linear time-invariant systems relative to time-multiplied quadratic performance indices is given, which appears to be a fundamental mistake.
Abstract: A procedure for the design of optimal feedback controls for linear time-invariant systems relative to time-multiplied quadratic performance indices is given in a recent paper. There appears to be a fundamental mistake in the procedure given and this is pointed out. A first-order example is also worked out to illustrate the present conclusion.
13 citations
TL;DR: In this article, the compaction pressures, porosities and compressive strengths of mixtures of materials of particle size (−1·60 + 1·00mm) are determined.
12 citations
TL;DR: The mechanism of formation of neuronal spike trains is studied on the basis of some counter models as well as the dependent models proposed by ten Hoopen and Reuver to obtain statistical properties of the response-yielding events.
Abstract: The mechanism of formation of neuronal spike trains is studied on the basis of some counter models as well as the dependent models proposed by ten Hoopen and Reuver. The statistical properties of the response-yielding events are explicitly obtained and some theorems dealing with the criteria for the response-yielding events to be distributed exponentially are deduced.
TL;DR: In this paper, a new method of solving linear single-input single-output optimal servo problems reducible to regulator problems is presented, where the starting point for the design procedure is the description of the plant in state-variable equations.
Abstract: A new method of solving linear single-input single-output optimal servo problems reducible to regulator problems is presented. The starting point for the design procedure is the description of the plant in state-variable equations, and there is no need to compute the transfer function of the plant. A numerical example is also worked out to illustrate the procedure.
TL;DR: In this article, the results of computational experiments to evaluate the procedures developed for five precision derivative (third order) and nine precision derivatives (fourth order) synthesis, with transmission angle control, of the seven link two-degree-of-freedom mechanism with double joint are presented along with the results.
TL;DR: In this paper, the problem of unsymmetric bending of cylindrical conical shell junction has been analyzed and an exact solution has also been worked out in order to indicate how such problems can be tackled by non-numerical methods and the results of this solution have been compared with the results obtained by the numerical method.
TL;DR: In this paper, a new tensor formulation is proposed in which the physical properties (in particular the piezoelectric property) of crystals can be specified without reference to any coordinate system.
Abstract: In writing out tensors which represent physical properties of crystals, it is customary to choose a Cartesian frame of reference which has a specific orientation with respect to the crystallographic axes. A new formulation is proposed in which the physical properties (in particular the piezoelectric property) of crystals can be specified without reference to any coordinate system.
Bei der Darstellung der Tensorgrosen von Kristallen ist es ublich, ein kartesisches Koordinatensystem zu wahlen, das eine bestimmte Orientierung zu den Kristallachsen hat. Eine neue Formulierung wird vorgeschlagen, mit deren Hilfe die physikalischen Eigenschaften eines Kristalls (besonders die piezoelektrischen Eigenschaften) unabhangig vom Koordinatensystem beschrieben werden konnen.
01 May 1970
TL;DR: In this paper, generalized harmonic analysis was applied to solve the linear response problem of vibrating elastic plates with damping under stochastic pressure, and the power spectral density of the external pressure was taken to be of a typical peaked shape resembling actual physical conditions.
Abstract: Generalized harmonic analysis was applied to solve the linear response problem of vibrating elastic plates with damping under stochastic pressure. The power spectral density of the external pressure was taken to be of a typical peaked shape resembling actual physical conditions. The spatial correlation of pressure over the plate area was taken to be unity. Results give the cross-correlation functions for the acceleration and stresses in terms of the mean-square value of the load and the characteristic constants used to describe the power spectral density curve. For the centres of rectangular plates with simply-supported and built-in edges dimensionless response autocorrelation functions are plotted.
TL;DR: A brief review of the available literature on the bulk viscosity in liquids is given in this article, where some important experimental methods for the determination of this quantity are discussed and the role of the bulk viscosity in other branches of science is also briefly considered.
TL;DR: The fundamental absorption band edge of NaClO 3 crystal showed a shift towards longer wavelengths with increase in temperature and there is also evidence of formation of a new band at temperature higher than about 120°C.
TL;DR: In this paper, a method of describing systems by sets of second-order differential equations is suggested, which reduces the order of matrices, renders easier the evaluation of the characteristic equation and the system solution, and provides some additional insight into the relative stability of system states.
Abstract: A method of describing systems by sets of second-order differential equations is suggested. In this second-order state-space formulation the states are defined in a manner slightly different from the conventional one. It is shown that this modified procedure reduces the order of matrices, renders easier the evaluation of the characteristic equation and the system solution, and provides some additional insight into the relative stability of system states. Procedures of characterization and analysis of systems by this modified method are indicated, and an example is considered to illustrate the advantageous features of the method in contrast with the normal procedure.
01 Jan 1970
TL;DR: In this paper, the authors extend these results to obtain the formula for the number of self-complementary oriented graphs on n points and the generating function for self-converse oriented graphs in terns of the total number of lines.
Abstract: De Bruijn [I] applied his genoralization of POlya's fundamental theorem to provide an outline of a general method for enumerating self-complementary structures. This was used by Read [8] to carry out in detail the enumeration of self-complementary graphs and digraphs. Suitable modifications of the same scheme gave Harary and Palmer [4], [5] the basic clue for their enumeration of self-converse digraphs. In this paper we extend these results to obtain the formula for the number of self-complementary oriented graphs on n points and the generating function for self-converse oriented graphs in terns of the number of lines.
TL;DR: Spark hardening as discussed by the authors is a process by which a wear-resistant material is deposited on the surface of steel components and cutting tools by the action of electric sparks, forming a fused hardened skin.
TL;DR: It is shown that the results of ten Hoopen and Reuver can be generalized in a direct manner using the techniques of point processes.
Abstract: The interaction between a recurrent process and another point process generated by the former is considered in the light of a model proposed by ten Hoopen and Reuver. It is shown that the results of ten Hoopen and Reuver can be generalized in a direct manner using the techniques of point processes.
TL;DR: In this paper, the Lyapunov matrix equation was proved in a simpler manner, and a theorem was proved on the same basis. But this theorem was later disproved in a much simpler manner.
Abstract: Man proves a theorem on the Lyapunov matrix equation. This theorem is proved in a much simpler manner.
TL;DR: The probability density of the lysis of an infected bacterium is examined, and the expressions for the mean number of vegetative and mature phages at the time of the burst are derived.
Abstract: The probability density of the lysis of an infected bacterium is examined on the hypothesis that the bacterial burst is dependent on the amount of toxic product (volume considerations), and the expressions for the mean number of vegetative and mature phages at the time of the burst are derived. A hierarchy of equations for the bacteria with multiple attachments are indicated. To have an idea of the time for extinction of a bacterial colony subject to phage attack, an approximate model is discussed.
TL;DR: In this paper, a dual input discrete describing function reduces to the ordinary describing function of a saturating amplifier and a relay with dead zone when triangular and square wave stabilizing signals are used.
Abstract: In a previous correspondence, stabilization of relay-type discrete systems using high-frequency sinusoidal dither, by the method of a dual input discrete describing function was discussed. The dual input discrete describing function reduces to the ordinary describing function of a saturating amplifier and a relay with dead zone when triangular and square wave stabilizing signals are used.
TL;DR: In this paper, the authors present a correlation between the drill temperature with cutting speed and feed while drilling cast iron and derive the tool-life equation on the basis of temperature data, which agrees well with that obtained by conventional test.
Abstract: Earlier investigation has shown that, from the point of view of flank wear, tool-life can be predicted by the initial cutting temperature. This paper presents a correlation between the drill temperature with cutting speed and feed while drilling cast iron and derives the tool-life equation on the basis of temperature data. The equation obtained agrees well with that obtained by conventional test.
TL;DR: In this paper, the characteristic functional of the cumulative response at any time t is obtained when the light quanta arrive according to any general point process, their lifetimes being independently, identically, and arbitrarily distributed.
Abstract: Light quanta arrive at times τ 1 , τ 2 ,… on the retina of one eyes of an observer, each quantum giving rise to a unit response, lasting its lifetime. The characteristic functional of the cumulative response at any time t is obtained when the light quanta arrive according to any general point process, their lifetimes being independently, identically, and arbitrarily distributed. Various quantities of interest in the sensory phenomenon are discussed.
TL;DR: This correspondence points out the inadequacy of the discrete describing function method in predicting certain modes of oscillations in a class of relay sampled-data systems and the necessary change in critical regions is suggested to predict the correct mode of oscillation.
Abstract: This correspondence points out the inadequacy of the discrete describing function method in predicting certain modes of oscillations in a class of relay sampled-data systems. These modes, however, do not exist in this class of systems. This must be ascertained before the previously mentioned method could be applied to determine all the possible modes of a system. Furthermore, the necessary change in critical regions is suggested for this class of systems to predict the correct mode of oscillation.
TL;DR: In this correspondence Popov's method is used to find the minimum amplitude of the dither to be applied to quench the limit cycles occurring in relay type nonlinear control systems.
Abstract: In a previous paper [1], a new method called the dual input discrete describing function (DIDDF) was presented, which enables one to determine the minimum amplitude of sinusoidal dither to be applied, to stabilize a relay type sampled-data control system. In this correspondence Popov's method is used to find the minimum amplitude of the dither to be applied to quench the limit cycles occurring in relay type nonlinear control systems. Furthermore, the dependence of the minimum value of the dither on sampling time is explicitly seen in Popov's method.
TL;DR: In this paper, a partial difference equation governing the lateral buckling of a simply supported uniform diagrid is obtained using slope-deflexion equations for two orthogonally intersecting beams.