Showing papers by "Indian Institute of Technology Kharagpur published in 1971"
TL;DR: In this article, the steady flow in a parallel plate channel rotating with an angular velocity Ω and subjected to a constant transverse magnetic field is analyzed and an exact solution of the governing equations is obtained.
Abstract: The steady flow in a parallel plate channel rotating with an angular velocity Ω and subjected to a constant transverse magnetic field is analysed. An exact solution of the governing equations is obtained. The solution in the dimensionless form contains two parameters: the Hartmann number, M2, and K2 which is the reciprocal of the Ekman number. The effects of these parameters on the velocity and magnetic field distributions are studied. For large values of the parameters, there arise thin boundary layers on the walls of the channel.
43 citations
TL;DR: From a series of electron micrographs of the primary xylem cell, at various stages of development, it has been concluded that the microtubules are instrumental for localized thickening of the tracheids.
31 citations
TL;DR: In this article, the kinetics of methanol to formaldehyde and carbon dioxide were studied in the temperature range 264-290 °C over a silver catalyst, using a differential flow reactor operating at a low conversion level under atmospheric pressure.
23 citations
TL;DR: In this article, a diacetylazine-dioximate ion is bonded to Cu(II and Ni(II) in a bi-bidentate manner, and magnetic susceptibility values over a range of temperature show the presence of antiferromagnetic exchange interaction in these systems.
21 citations
TL;DR: The supposed Aravalli basal conglomerate near Morchana, considered to mark an erosional unconformity above the older Precambrian Banded Gneissic Complex in central Rajasthan, is a tectonic melange in a terrain involved in superposed deformations as discussed by the authors.
Abstract: The supposed Aravalli basal conglomerate near Morchana, considered to mark an erosional unconformity above the older Precambrian Banded Gneissic Complex in central Rajasthan, is a tectonic melange in a terrain involved in superposed deformations. The supposed pebbles represent tectonic inclusions of various shapes, formed by isoclinal folding, stretching and disruption of concordant, pre- or early-kinematic vein quartz and rare pegmatite sheets in the Aravalli mica schist during the first folding.
15 citations
14 citations
TL;DR: In this article, Bhattacharyya et al. showed that vanadium pentoxide prepared by the decomposition of vanadyl oxalate (catalyst I) has better catalytic activity for certain oxidation reactions than the one prepared by ammonium metavanadate (Catalyst II).
12 citations
TL;DR: Complex uranyl fluorides of the general formulae BH 2 [UO 2 F 4 ]· n H 2 O, M II [BH 2 ]· NH 2 O and M 2 I [M 2 I] have been isolated in pure state as discussed by the authors, where B = organic diamine base, viz biguanide and phenyl biguanides, and M II = Ba 2+ and bivalent complex cations.
11 citations
TL;DR: In this article, experiments were conducted under which rice plants were grown under three energy input levels (temperature and light) and two solution-oxygen concentrations, and the rice variety was Colusa.
Abstract: Experiments were conducted under which rice plants were grown under three energy input levels (temperature and light) and two solution-oxygen concentrations. The rice variety was Colusa. Increasing the energy input increased total top growth. There was no significant effect of solution-oxygen concentration on top growth. The highest number of tillers developed under medium energy input followed by high energy input and the least under low energy input. There was a trend towards more tiller production under low oxygen conditions as compared to high oxygen. Decreasing the oxygen supply increased the dry weight production of roots under the two higher energy input levels, but had no significant effect under the low energy input. The highest amount of root growth occurred under high and medium energy input and least under lower energy input. Increasing the energy input increased the percent root porosity, but the oxygen level had no significant effect on root porosity. None of the treatments had a significant effect on nitrogen concentration in the tops. The amount of water necessary per unit dry matter production had a trend towards increase with increased energy input level and also significantly higher under low oxygen as compared to high oxygen conditions.
11 citations
TL;DR: In this paper, the hydraulic resistance to flow in vegetated and non-vegetated border strips were evaluated by conducting a series of field experiments on specially prepared test border strips and found that the values of the Reynolds number R n were above 5000 in all tests.
10 citations
TL;DR: The arcuate map pattern is due to coaxial refolding of the axial surface of the isoclinal fold, on which open, NNE-trending upright folds have been overprinted.
Abstract: The marble band of supposedly Raialo (Precambrian) age around Rajnagar in the Udaipur district of Rajasthan represents a large isoclinal fold with the two limbs coalesced and with the terminations marking the sharp hinges. The arcuate map pattern is due to coaxial refolding of the axial surface of the isoclinal fold, on which open, NNE-trending upright folds have been overprinted. The isoclinal folds of small scale are reclined or inclined in style and plunge gently westward where not involved in the upright folding. The axes of the isoclinal folds have been scattered by superposed folding, so that some of the isoclinal folds now plunge even to the south. The plunge of the upright folds is gentler and steeper in the limb zones of reclined and inclined isoclinal folds respectively. Subvertical upright folds occur only in the hinges of the westerly trending reclined folds. Interference patterns of dome-and-basin type and mirror-image type have formed in zones where both hinges and limbs of the early folds have been affected by upright folding. The structure of the marble band, the stratigraphic relations that the marble bears with the supposedly older Aravalli mica schists and migmatites of the Banded Gneissic Complex engulfing it, and the stratigraphic findings in adjacent terrains indicate that the Banded Gneissic Complex represents migmatized portions of the metasediments of the Aravalli and the Raialo groups, and is not the basement rock in central Rajasthan. Evidence for granitic rocks of at least two generations in the Early Precambrians of central Rajasthan is adduced.
TL;DR: In this paper, the results of measurements on manganese-doped CaF2 crystals irradiated with X-rays are reported: (i) optical absorption characteristics (in the region 220 to 800 nm) after irradiation at elevated temperatures, (ii) growth of colour centres at 30 °C with time of irradiation, (iii) bleaching characteristics of coloured CAF2:Mn (5 mol%) with UV light and (iV) thermoluminescence emission of CaF 2:mn (1 and 5 mol%) as a function of irrad
Abstract: Results of the following measurements on manganese-doped CaF2 crystals (with 1 and 5 mol% of manganese content) irradiated with X-rays are reported: (i) optical absorption characteristics (in the region 220 to 800 nm) after irradiation at elevated temperatures, (ii) growth of colour centres at 30 °C with time of irradiation, (iii) bleaching characteristics of coloured CaF2:Mn (5 mol%) with UV light and (iV) thermoluminescence emission of CaF2:Mn (5 mol%) as a function of irradiation time. An attempt has been made to understand these results.
Es wird uber Untersuchungen an Mangan dotierten CaF2-Kristallen berichtet, die mit Rontgenstrahlen behandelt wurden. Folgende Messungen wurden durchgefuhrt: (1) Charakteristiken der optischen Absorption (im Bereich zwischen 220 und 800 nm) nach Bestrahlung bei Temperaturen, (2) Zunahme der Zahl der Farbzentren mit der Bestrahlungs-hoheren dauer bei 30 °C, (3) Ausbleichung von verfarbtem CaF2:Mn (5 Mol%) mit UV-Lict und (4) Thermolumineszenzemission von CaF2:Mn (5 Mol%) in Abhangigkeit von der Bestrahlungsdauer. Es wird der Versuch gemacht, die Ergebnisse zu erklaren.
TL;DR: In this paper, a Salz-Konzentrations-gradient-gradient is proposed, in which the Schicht gegenuber Stromungen endlicher Amplitude instabil wird, bevor infinitesimale Storungen anwachsen.
Abstract: Die Stabilitatseigenschaft einer von unten erwarmten, unendlich ausgedehnten, horizontalen Flussigkeitsschicht wird untersucht in dem Fall, wenn ein stabilisierender Salz-Konzentrations-gradient gegeben ist und die Flussigkeitsschicht mit konstanter Winkelgeschwindigkeit um eine vertikale Achse rotiert. Die Untersuchung infinitesimaler Storungen zeigt, dass das System zuerst gegenuber oszillierenden Storungen instabil wird. Daruber hinaus wird an dem Beispiel von Stromungen in der Form von Rollen gezeigt, dass die Schicht gegenuber Storungen endlicher Amplitude instabil wird, bevor infinitesimale Storungen anwachsen. Die Rotation ubt eine stabilisierende Wirkung aus. Der Einfluss von Rotation und Salz-Konzentrationsgradient auf den Warmetransport wird diskutiert.
TL;DR: In this article, the Mahalanobis' generalized distance functions (D2) between all pairs of the 10 sets of granitic rocks (20-50 samples in each set) from magmatic units of the Singhbhum granite were used for computation of the multivariate means.
Abstract: The weight-percent values of four mineralogic variables (quartz, K feldspar, color index, and muscovite) for 10 sets of granitic rocks (20–50 samples in each set) from magmatic units of the Singhbhum granite were used for (1) computation of the Mahalanobis' generalized distance functions (D
2) between all pairs of the 10 sets, (2) testing significance of the difference between the multivariate means, and (3) computation of the linear discriminant functions between all possible pairs of the sets. The 10 data sets are for six magmatic units which belong to three successive but closely related phases of emplacement. The multivariate means for all sets are significantly different except for those between two of the sets of phase I. Cluster analysis on the basis of theD
2 values enables the 10 sets to be placed into four distinct groups. Group A includes two subgroups, one of which consists of two sets representing typical members of phase I; the other subgroup includes two sets which are typical of phase II. Group B includes two sets which are typical of phase III. The other four sets do not group with the typical representatives of the three phases, probably because of certain special conditions of their emplacement. A separate series ofD
2 computation from the same data, but excluding the color index, was unsuccessful in making the four aberrant sets group with the typical members of the respective phases. Efficient LDF's could be determined for discrimination between most pairs of the 10 sets of granite rocks.
TL;DR: In this article, the emf of the cell Pt, H 2 ; HCl( m ); Hg 2 Cl 2, Hg has been measured at 25° using formamide as the solvent.
TL;DR: In this article, the luminescence spectrum and its temperature dependence for calcium-fluoride crystals excited by low-energy electrons are found to be those obtained by X-ray irradiation except for a difference in the relative intensities of some regions of emission.
TL;DR: In this article, the observed ionospheric effects of the X-ray flare on July 8, 1968, which was of considerable importance both from the ionosphere and solar physics point of view, were examined in order to derive a suitable physical model of flare-induced ionization below 100 km.
TL;DR: Water requirement of rice was highest at 10 cm. but crop performance was similar to that at 5 cm. as discussed by the authors showed that transpiration, evaporation, and percolation losses were greater under submergence, and only transpiration was greater under higher levels of fertilization.
Abstract: Under the three levels of submergence (0, 5 and 10 cm. depths), water requirement of rice was maximum at 10 cm. but crop performance was similar to that at 5 cm. With medium and high levels of fertilization the crop had a higher water requirement than under low level, for ‘aus’ and ‘aman’ crops. Compacted soil compared well with puddled soil, but water requirement was appreciably higher with shallow puddling. In the two seasons water requirement, transpiration, evaporation and percolation losses were greater under submergence, and only transpiration was greater under higher levels of fertilization. Transpiration was maximum at flowering stage.
TL;DR: In this article, the functional relationship between advance distance and elapsed time and accumulated infiltration in a border strip has been investigated, and two different equations have been developed to describe the water front advance-time relationship.
TL;DR: In this paper, the authors derived physical models of the emitting regions of the Sun under quiescent (non-flare) conditions using 9.1 cm solar spectroheliograms for 1237 days during the period July 1966 to June 1970.
Abstract: 1–8 A, 2–12 A and 8–20 A non-flare X-ray flux data and 9.1 cm spectroheliograms for 1237 days during the period July 1966 to June 1970 have been studied to derive physical models of λ < 20 A X-ray emitting regions on the Sun under quiescent (non-flare) conditions. The preferred regions of emission below 20 A which coincide with the coronal active regions characterised by enhanced 9.1 cm microwave emission are found to have temperature lying between 1.8 and 3 × 106 K, emission measure 1049–1050 and electron density 109-1010 per cc. The average area of an active region is 1020 cm2. A slow gradient of temperature and electron density is seen to exist around a region of peak activity, both temperature and electron density decreasing outwards. Based on the derived physical model of the emitting regions a new method is presented for calculating X-ray flux and spectral energy distribution in this wave length region using daily 9.1 cm solar spectroheliograms. The calculated values are in good agreement with the observed values.
TL;DR: In this paper, a review of synthetic methods for the final stap of cyclic amides through the formation of the C3-C4 bond is presented. But the main focus of this paper is on the C4 bond.
TL;DR: In this article, the integrated density of three-dimensional disordered systems with spherical-well type of atomic potential is computed, and two approximate procedures are used for evaluating the dressed electron propagator relevant to the perturbational treatment: a pertubational treatment based on Klauder's approach and a nonperturbational semiclassical method based on Bonch-Bruevich's treatment.
Abstract: The integrated density fo electronic states, g(E), of three-dimensional disordered systems with spherical-well type of atomic potential is computed. A pertubational treatment (based on Klauder's approach) and a non-perturbational semiclassical method (based on Bonch-Bruevich's treatment) have been used for the purpose; two approximate procedures being used for evaluating the dressed electron propagator relevant to the perturbational treatment. Various features of the results of the two treatments are compared and discussed critically. In particular, it is observed that the semiclassical treatment yields a tailing o g(E) extending up to arbitrarily low energies and both the treatments show an overal decrease of g(E) with concentration.
Die integrale Dichte der Elektronenzustande, g(E) eines dreidimensionalen fehlgeord-neten Systems mit einem spharischen Atompotentialtopf wird berechnet. Eine Storungs-methode (auf der Grundlage von Klauders Verfahren) und eine halbklassische, nicht-storungstheoretische Methode (auf der Grundlage von Bonch-Bruevichs Behandlung) wurde zu diesem Zweck benutzt; zwei Naherungsmethoden werden zur Berechnung des fur die Storungsbehandlung zweckmasigen, „angezogenen” Elektronenpropagators verwendet. Die verschiedenen Merkmale der Ergebnisse der beiden Verfahren werden verglichen und kritisch diskutiert. Insbesondere wird beobachtet, das die halbklassische Behandlung Schwanze von g(E) ergibt, die sich zu beliebig niedrigen Energien erstrecken. Beide Methoden zeigen einen Gesamtabfall von g(E) mit der Konzetnration.
TL;DR: In this paper, the acceleration of sulfuration of natural rubber both in the presence and absence of dicumyl peroxide (DCP) has been studied, and it is observed that with constant level of DCP and sulfur, crosslinking increases with the increase of DPG concentration and finally becomes additive when the molar proportion of DCP: S8 approximately equals 1:1.
Abstract: Diphenylguanidine acceleration of sulfuration of natural rubber both in the presence and absence of dicumyl peroxide (DCP) has been studied. DPG enhances the rate of decomposition of DCP, and the crosslinking maxima due to DCP are lowered by DPG to some extent, which increases with the concentration up to a limiting value. The rate of sulfur decrease is very high and is dependent on DPG concentration but practically independent of the presence of ZnO and stearic acid. It is observed that with constant level of DCP and sulfur, crosslinking increases with the increase of DPG concentration and finally becomes additive when the molar proportion of DPG: S8 approximately equals 1:1. In presence of ZnO and stearic acid, with each increment of DCP concentration crosslinking is retarded for both systems. Mechanisms have been suggested in terms of polar and radical process.
Journal Article•
TL;DR: In this paper, a rational explanation in the tectonic model drawn from the geometry of directly observable structures was provided for superposed deformations in the Precambrian terrain around Jawad in the Udaipur district, Rajasthan.
Abstract: Folds of different style and orientation, bent hinges of folds, curved lineations on folded or planar foliation, folds torn to form boudins and tectonic inclusions of diverse shapes, chocolate-tablet boudins, interference patterns like mirror-image type folds, irregular domes-and-basins and eyed folds-all these small-scale structures provide ample evidence for superposed deformations in the Precambrian terrain around Jawad in the Udaipur district, Rajasthan. Variation in the attitude of foliation, axial planes and axes of small folds of different styles and the related lineations finds a rational explanation in the tectonic model drawn from the geometry of directly observable structures.
TL;DR: In this paper, the flow of a dipolar fluid between two parallel plates with and without heat transfer is studied, and the following cases are discussed, without and with heat transfer:
Abstract: The flow of a dipolar fluid between two parallel plates with and without heat transfer is studied. The following cases are discussed:
TL;DR: In this paper, the integrated density of electronic states [g(E)] was investigated for one-dimensional disordered systems with rectangular-well type potentials, and the tailing of g(E) extending up to arbitrarily low energies and no forbidden energy region.
TL;DR: In this paper, triplet energy levels and triplet-triplet transition in benzene have been calculated semi-empirically by considering CI up to and including doubly excited configurations and using various values of the core resonance and electron repulsion integrals.
Abstract: Triplet energy levels and triplet–triplet transition in benzene have been calculated semi-empirically by considering CI up to and including doubly excited configurations and using various values of the core resonance and electron repulsion integrals. The usual method of calibrating β (core resonance integral) from one of the observed transitions in the semi-empirical methods is critically examined with respect to the triplet levels of this molecule. Semi-empirical parameters are found to have a pronounced effect on the energy of the triplets and the triplet–triplet transitions; but the intensities of such transitions are quite insensitive to the choice of such parameters.
Numerical results show several 3B1u 3E2g transitions of various intensities. Out of these, the transitions which correspond energetically to the observed triplet–triplet bands are found to have low intensity. Some strong triplet–triplet bands are predicted in the far ultra violet region.