Showing papers by "Jadavpur University published in 1970"
TL;DR: Theoretical studies show that when a thin viscous layer embedded in a viscous medium is subjected to compression in two perpendicular directions in the plane of the layer, the lengths of arc in the two directions, λ 1 and λ 2, are related by the equation as mentioned in this paper.
38 citations
TL;DR: PPA and Friedel-Crafts cyclizations of the bromo-acid (mixture) obtained by nuclear bromination of VII furnished three isomeric bromoketones characterised as XII, XI and XVI as discussed by the authors.
29 citations
TL;DR: Some amino acids, particularly glycine and serine, favour the accumulation in the fermentation broth of three phosphorylated amino sugar compounds that are intermediates in the pathway of neomycin biosynthesis by Streptomyces fradiae 3535.
Abstract: Some amino acids, particularly glycine and serine, favour the accumulation in the fermentation broth of three phosphorylated amino sugar compounds that are intermediates in the pathway of neomycin biosynthesis by Streptomyces fradiae 3535. The compounds were separated and purified further by Amberlite IRC-50 (NH4+ form). The intermediates were characterized by physicochemical methods as neomycin B pyrophosphate (C23H48N6O19P2,3H2O), neomycin C pyrophosphate (C23H48N6O19P2,3H2O) and neomycin C dipyrophosphate complex (C24H66N8O33P4).
28 citations
TL;DR: In this paper, mixed complexes of La(III, Pr(III), Nd-III, Eu-III and Tb-III with general formula M ( phen ) 2 (sal ) 3 have been prepared and their u.r. spectra have been studied.
25 citations
TL;DR: In this paper, it was shown that the sector ordering problem can be transformed into a spatial location problem, and the ordering index becomes associated with notions of distance, and that if this approach is taken in the ordering of sectors, it is possible to develop the following useful properties with respect to input-output matrices: i) an ordering of the sectors in an input output matrix which is in some meaningful sense optimal; ii) a measure of sectoral interdependence of an economy; iii) an optimal ordering of location for units of an industrial complex visualised as a whole
Abstract: In input-output research comparatively little work has been done on the ordering of sectors. As the sectors can be ordered more or less arbitrarily, this has been left generally to the prevalent systems of national accounts and other economic data. The traditional data systems thus rather than any specific lcgic seems to have determined such procedures. One of the authors, 1 in an earlier note showed that certain ordering of sectors reveal an interesting clustering property in input-output matrices which have certain advantages both in understanding the economy as also in computational work. The present note discusses certain other aspects of the problem of ordering. The flows in an input-output matrix looks in certain ways rather similar to the flows from origin to destination in a transportation model. Viewed from this angle, one can look at the sector ordering as analogous to fixing the location of both the centres of origin and the ultimate destination of a group of commodities. The important difference of course is that unlike a transportation problem, here the origins and destinations can be moved about, subject to certain rules. In this sense, therefore, we can look at the flow matrices under different ordering as alternative spatial configurations under certain sets of rules. The ordering problem is then to some extent transformed into a spatial location problem and the ordering index becomes associated with notions of distance. It will be shown that if this approach is taken in the ordering of sectors we are enabled to develop the following useful properties with respect to input-output matrices: i) An ordering of the sectors in an input-output matrix which is in some meaningful sense optimal; ii) A measure of sectoral interdependence of an economy; iii) An optimal ordering of location for units of an industrial complex visualised as a whole.
18 citations
TL;DR: By using 8 indicator strains, 11 bacteriocin types have been recognized among 425 strains, of which 87% are typable at present, and appeared to be powerful diffusible bactericidal agents.
Abstract: Bacteriocins of Vibrio cholerae have been demonstrated against enterobacterial and vibrio indicator organisms by conventional techniques. Abundant bacteriocin production took place on casein hydrolysate-yeast extract, tryptic soy, digest broth, proteose-peptone, and neopeptone agars. Essential factors were a citrate-phosphate buffer concentration of 0.5 to 0.7%, at p H 7.5 to 7.6, and cold shock. Thermal treatment of indicator organisms at 45 C for 12 min increased the percentage of typable strains. The bacteriocins of V. cholerae appeared to be powerful diffusible bactericidal agents. By using 8 indicator strains, 11 bacteriocin types have been recognized among 425 strains, of which 87% are typable at present. Images
15 citations
TL;DR: The study showed that Tween 80 hydrolysis can be used as a test for characterization of the Vibrio and Aeromonas groups and for their differentiation from the Enterobacteriaceae.
Abstract: Summary.
A total of 307 strains consisting of 89 Vibrio cholerae, 37 NAG vibrios, 4 Aeromonas sp., 20 Pseudomonas aeruginosa, 47 shigellae, 59 Escherichia coli, 27 Proteus mirabilis and 25 salmonellae were examined for their opacity reaction in Tween 80 agar medium. Strong reactions occurred with 87 V. cholerae, 26 NAG vibrios, 2 Aeromonas and 5 Pseudomonas strains; and weak and slow positive reactions were noted in only 6 strains of NAG vibrios and 3 of Pseudomonas; no reaction was observed among the remaining strains. The study showed that Tween 80 hydrolysis can be used as a test for characterization of the Vibrio and Aeromonas groups and for their differentiation from the Enterobacteriaceae.
14 citations
TL;DR: In this article, a grounded inductor simulation with a differential amplifier is presented, where the differential amplifier can be used to simulate the ground inductor and the differential inductor.
Abstract: (1970). Grounded inductor simulation with a differential amplifier. International Journal of Electronics: Vol. 28, No. 5, pp. 481-483.
12 citations
TL;DR: In this paper, a digitally controlled variable-gain amplifier with a constant tail current is described, which can be used as a digital attenuator. But the performance of the amplifier is limited by the voltage of the digital-to-analogue converter.
Abstract: A digitally controlled variable-gain amplifier is described. Such circuits have applications in digital-to-analogue conversion, waveform generation, amplitude sweeping and in various other fields. The present circuit employs a differential amplifier with a constant tail current, controlled by the d.c. output voltage from a digital-to-analogue converter. The unique features of the circuit are its capability of amplifying both d.c. and a.c. signals and of being used as a digitally controlled variable attenuator. The temperature stability of the circuit is inherent.
9 citations
TL;DR: In this article, the authors studied the kinetics of chromic acid oxidation of glycollic and benzilic acids and showed that the logarithm of the rate constants increases with increase in the proportion of acetic acid in the mixture.
Abstract: The kinetics of chromic acid oxidation of glycollic and benzilic acids have been studied. Catalysis by H+ ions has been noticed in both cases of oxidation. The results show that the logarithm of the rate constants increases with increase in the proportion of acetic acid in the mixture. Ionic strength decreases the rate of oxidation. Pyridine catalyzes the oxidation of glycollic acid whereas the catalysis in the case of benzilic acid is negligible. The energy of activation and entropy of activation have been calculated. Both kinetics and spectrophotometric results indicate the formation of intermediate chromium (VI)-hydroxycarboxylate complex in each case. The complex finally decomposes to give reaction products. Glycollic acid initially produces glyoxylic acid which subsequently gives formic acid whereas benzilic acid is oxidized to benzophenone.
8 citations
TL;DR: Fe(III) is a 1 : 1 chelate with benzilate as mentioned in this paper, which is neutral and stable towards acid, and the equilibrium constant (K = 2.335 × 106) and change of free energy (−ΔG = 8.85 kcals) of formation are reported.
Abstract: Fe(III) forms a 1 : 1 chelate with benzilate. The equilibrium constant (K = 2.335 × 106), and change of free energy (−ΔG = 8.85 kcals.) of formation as well as the magnetic moment (μ = 6.0 BM) of the isolated solid complex have been reported. From elemental analyses and IR spectra cis-trans isomeric structures have been proposed. The complex is neutral and stable towards acid.
Eisen(III) ergibt mit Benzilsaure ein isolierbares, neutrales 1 : 1-Chelat (Gleichgewichtskonstante: K = 2,335 · 106; Anderung der freien Energie: −ΔG = 8,85 kcal; magnetisches Moment: μ = 6,0 BM). Auf Grund des IR-Spektrums werden mogliche cis/trans-isomere Strukturen vorgeschlagen.
TL;DR: In this paper, N-Benzoyl- o -tolylhydroxylamine has been used for the gravimetric determination of uranium(VI) by direct weighing of the complex.
TL;DR: In this article, a negative-impedance convertor suitable for the realisation of an inductor is presented, where the inductance and the associated resistive part are shown to be frequency-dependent if this condition is not exactly satisfied.
Abstract: A circuit consisting of a negative-impedance convertor, suitable for the realisation of an inductor, is presented. For a certain circuit condition the realisation is independent of frequency, and by the variation of a single capacitor the inductance value of the inductor can be varied over a wide range while the resistive part remains constant. Both the inductance and the associated resistive part are shown to be frequency-dependent if this condition is not exactly satisfied.
TL;DR: In this paper, the authors investigated the magnitude and nature of the tangential and radial component of cutting force during the conventional hobbing process, with the help of a specially designed hobbing dynamometer.
Abstract: The exacting demands for producing accurate gears make it necessary to determine the cutting forces coming on the hob-shaft which is the weakest element subjected to severe bending and torsion. The authors, with the help of a specially designed hobbing dynamometer, have investigated the magnitude and nature of the tangential and radial component of cutting force during the conventional hobbing process.
TL;DR: In this paper, a rotating cylindrical crystal of KCl was bombarded by 19 keV electrons, and the F-centre distribution observed as a function of the angle of rotation.
Abstract: A rotating cylindrical crystal of KCl was bombarded by 19 keV electrons, and the F-centre distribution observed as a function of the angle of rotation. Eight maxima were found corresponding to different angular positions of the crystal. The depth of coloration was measured along the and axes in KCl and KBr crystals. In both the crystals the magnitude of coloration was higher along axes than along axes, but the depth of coloration or the electron range had been found to be longer along the latter direction. The results are interpreted in terms of channeling effect.
Ein rotierender zylindrischer Kristall von KCl wurde mit 19 keV-Elektronen bombariert und die F-Zentrenverteilung als Funktion des Drehungswinkels beobachtet. Es wurden acht Maxima gefunden, die verschiedenen Winkellagen des Kristalls entsprechen. Die Tiefe der Verfarbung wurde langs der - und -Achsen in KCl-und KBr-Kristallen gemessen. In beiden Kristallen war die Starke der Verfarbung langs der -Achsen groser als langs der -Achsen es wurde jedoch gefunden, das die Tiefe der Verfarbung oder die Elektronenreichweite groser in der -Richtung war. Die Ergebnisse werden mit dem Channeling-Effekt interpretiert.
TL;DR: In this article, a short-range three-body interaction which arises from the deformability of the charge cloud of an atom is included in the interaction between atoms of an inert gas solid and its effect on the dispersion curves and elastic constants is discussed.
Abstract: A short-range three-body interaction which arises from the deformability of the charge cloud of an atom is included in the interaction between atoms of an inert gas solid and its effect on the dispersion curves and elastic constants is discussed. The result is applied to krypton. Experimental dispersion curves, the bulk modulus at absolute zero, and the Debye temperature are compared with calculated values. It is found that on the whole the inclusion of the three-body potential improves the agreement.
Eine Dreikorper-Nahwechselwirkung, die von der Deformierbarkeit der Ladungswolke eines Atoms herruhrt, wird in die Wechselwirkungen zwischen den Atomen fester Edelgase einbezogen und ihr Einflus auf die Dispersionskurven und elastischen Konstanten diskutiert. Die Ergebnisse werden auf Krypton angewendet. Experimentell ermittelte Dispersionskurven, der Volumenmodul am absoluten Nullpunkt und die Debye-Temperatur werden mit berechneten Werten verglichen. Es wird gefunden, das die Einbeziehung des Dreikorperpotentials die Ubereinstimmung im ganzen verbessert.
TL;DR: The reaction between salicylaldehyde andPrimary amines in chloroform is utilised for analysis of binary mixtures of primary amines by the differential rate technique and the resolution is effected by graphical extrapolation from the usual second-order plots.
TL;DR: In this paper, the Verhaltnis der Schlupfgeschwindigkeit bei irgendeiner Feststoff-Konzentration λ is discussed.
Abstract: Die Abhangigkeit der Schlupf- oder Relativgeschwindigkeit zwischen Teilchen und Flussigkeit von den physikalischen Eigenschaften des Systems und der Teilchenkonzentration wurde fur sehr verschiedene Systeme in absatzweise betriebenen Wirbelschichten untersucht. Die Untersuchung erstreckt sich uber einen weiten Bereich der auf die Geschwindigkeit des freien Falls bezogenen Reynolds-Zahl Re. Das Verhaltnis der Schlupfgeschwindigkeit bei irgendeiner Feststoff-Konzentration λ zu der bei der Feststoff-Konzentration Null, usλ/uso, ist eine eindeutige Funktion von Re und lamda;. Es zeigte sich, das die Oberflachenspannung der Fliissigkeit keinen Einflulj auf das Verhaltnis der Schlupfgeschwindigkeiten usλ/uso hat.
TL;DR: In this paper, a feedback system consisting of an amplifier and an activo RC filter has been described, where the frequency of oscillations can be varied over a wide range by the variation of the gain of the amplifier.
Abstract: A feedback system consisting of an amplifier and an activo RC filter hag been described. It is observed that for certain variations in the filter configurations and for both positive and negative gains of tho amplifier sine wave oscillation is generated in the system for specific system conditions. The frequency of oscillation can be varied over a wide range by the variation of the gain of the amplifier. Expressions for the frequencies of oscillations in the oscillatory modes have been given and the conditions of oscillations have been derived. The analysis has been experimentally supported.
TL;DR: Using the Ornstein-Zernike distribution function, the dielectric behaviour of binary critical mixtures has been investigated in this article, where the local field has been found to reduce to that of Debye's formula giving rise to the sharp increase in ∈ 1 as T approaches T c.
Abstract: Maleic acid derivatives of hydroxy sulfonated fatty acid esters were prepared by heating the lauric acid salt of 1-chloro-2-hydroxypropane-3-sulfonic acid (NaCHPS) with maleic anhydride under reflux The surfactants thus obtained exhibited superior foaming and wettability to initial detergents that were prepared from lauric acid Amide derivatives of lauric surfactants were prepared by reacting sodium salt of lauric acid amide with NaCHPS under reflux, in the presence of cello-solve and xylene In acidic medium these amide derivatives possess better foaming properties and wettability than the initial detergents
An der Hydroxylgruppe sulfonierte Fettsaureester als oberflachenaktive Stoffe VI: Ester- und Amid-Derivate als Tenside
Die Maleinsaure-Derivate der an der Hydroxylgruppe sulfonierten Fettsaureester wurden durch Erhitzung von Laurinsauresalze der 1-Chlor-2-hydroxypropan-3-sulfonsaure (NaCHPS) mit Maleinsaureanhydrid unter Ruckflus hergestellt Die so erhaltenen Tenside weisen bessere Schaumfahigkeit und Benetzbarkeit auf als die ursprunglichen Detergentien, die aus Laurinsaure hergestellt wurden Durch Umsetzung von Natriumsalz des Laurinsaureamids mit NaCHPS unter Ruckflus bei Gegenwart von Cellosolve und Xylol wurden die Amid-Derivate des Laurinsaure-Tensids dargestellt In saurem Milieu besitzen diese Amid-Derivate bessere Schaumeigenschaften und Benetzbarkeit als die Ausgangsdetergentien
TL;DR: In this article, a method of synthesizing a socondordor all-pass transfer function with an RC null network and commercially available amplifiers is described, and a method for synthesizing socondor all pass transfer functions with RC null networks is presented.
Abstract: A method of synthesizing a socond-ordor all-pass transfer function with an RC null network and commercially available amplifiers is described
TL;DR: In this paper, it is shown that linearity of transformation is a mathematical consequence of the principle of relativity, and that it can be deduced from some basic physical facts, such as the curvature of the Lorentz transformation.
Abstract: In deductions of Lorentz transformations of the special theory of relativity, linearity of transformation is always postulated. There are only a few discussions about this linearity in which it is deduced from some basic physical facts. Here, it is shown to be almost a mathematical consequence of the principle of relativity.
01 Mar 1970
TL;DR: A method for the determination of copper(II) with a new spectrophotometric reagent β-benzoyl-α-pyridyl thiourea is described in this article.
TL;DR: In this article, the problem of disturbances has been investigated in two perfectly conductive media-an ideal liquid and a viscoelastic solid of three-parameter type-acted upon by a magnetic field.
Abstract: In this note, the problem of disturbances has been investigated in two perfectly (electrically) conductive media-an ideal liquid and a viscoelastic solid of three-parameter type-acted upon by a magnetic field. The electromagnetic equations of Maxwell and the equations of mechanical motion together with the stress-strain relation of the viscoelastic material of three-parameter type have been used to work out the problem. The results exhibit the predominance of transient behaviour in the displacements as well as in the stresses.
TL;DR: In this article, an oscillatory closed-loop system with the cascade combination of a first-order all-pass network, an amplifier and a clipper is described, which is seen to generate a discontinuous oscillation whoso repetition rate is adjustable by gain variation of the amplifier.
Abstract: An oscillatory closed-loop system with the cascade combination of a first-order all-pass network, an amplifier and a clipper is described. It is seen to generate a discontinuous oscillation whoso repetition rate is adjustable by gain variation of the amplifier. Replacing the all-pass network by a composite filter, comprising the all-pass network cascaded to an RC integrator, the system is seen to generate a continuous oscillation for a certain gain condition of the amplifier. Analysis of the two systems is made separately and the theoretical results are experimentally verified.
TL;DR: The control circuit necessary for the operation of an automatic elevator which starts and stops at specified places and at specified time is presented and the results were found to be in conformity with the predicted operations.
Abstract: The control circuit necessary for the operation of an automatic elevator which starts and stops at specified places and at specified time is presented. At present the elevator operations are generally controlled by electromechanical relays with a large number of contacts and limit switches. Here it has been tried to dispense with relays and their contacts, limit switches etc., by the introduction of semiconductor logical and switching devices. Electronic counting technique has also been suitably used. Different logical and switching schemes to be used have been developed by writing all the logical and sequential operations in the form of constraint equations, then solving them with the help of Boolean algebra. Boolean operations are performed by different logical and switching circuits. The entire control circuit has been constructed and tested, and the results were found to be in conformity with the predicted operations. All the facilities provided in an operatorless automatic elevator are also provided by this static control circuit. It is not, however, claimed that this is the only static control circuit possible or that the circuitry used is optimum. The authors only feel that such an approach will help the elevator engineers in finding out the easiest solution to any elevator operation problem. This is surely not possible by looking at different operations as completely isolated and their circuit arrangements mutually independent.
TL;DR: In this paper, a single crystal of NaCl was bombarded with 25 keV electrons along (100) axis, and the corresponding depth of coloration due to F-centres was estimated.
Abstract: A single crystal of NaCl was bombarded with 25 keV electrons along (100) axis, and the corresponding depth of coloration due toF-centres was estimated. The number ofF-centres produced was compared with the number of incident electrons, and the rate ofF-centre production was found to be 52 per cent.
TL;DR: In this article, a system capable of generating continuous as well as discontinuous oscillations is described, which consists of a cascaded combination of a phase-inverting amplifier, a clipper and an active second-order RC all-pass network.
Abstract: A system capable of generating continuous as well as discontinuous oscillations is described. It consists of a cascaded combination of a phase-inverting amplifier, a clipper and an active second-order RC all-pass network—the output of the all-pass network being fed back to the amplifier. The analysis of the system is carried out with the help of the phase plane technique for idealized clipper characteristics and physical explanations have been given for results with non-ideal behaviour of the clipper.