Browsing by Issue Date, starting with "1994"

Now showing 1 - 20 of 331

Synthesis and spectroscopic studies of simple and mixed complexes of nickel(ii)and zinc(ii)with an azo dye
(1994) Mandalika S. Sastry; Udai P. Singh; Animesh K. Ghose
New simple and mixed complexes of 1-(2-pyridylazo)-2-naphthol (PAN) and 1,10-phenanthroline (phen) or 2,2'-bipyridyl (bipy) with nickel(II) and zinc(II) were synthesized and characterized by elemental analyses, conductivity, infrared, electronic spectra, room temperature magnetic measurements, and X-ray diffraction studies. The I.R. data suggest the coordination of PAN through oxygen and (pyridine) nitrogen, whereas phen and bipy coordinate through the pyridine nitrogens. The UV-Vis. spectra along with magnetic measurements favor a tetrahedral geometry for the complexes. The podwer X-ray diffraction studies indicate tetragonal symmetry for all these complexes except for Ni(II)-PAN-phen, which has orthorhombic symmetry. © 1994, Taylor & Francis Group, LLC. All rights reserved.
System identification via block pulse functions
(1994) T. Srinivasan
This paper presents a new approach to the problem of system identification of linear time invariant systems through the application of Block-Pulse Functions. The application of BPF in the identification of the system parameters results in a computationally convenient and extremely simple procedure involving elegant matrix algebra. This approach does not involve any iterations.
Studies on the rf squid effect in tl-ca-ba-cu-o thin films prepared by the spray pyrolysis technique
(1994) N. Khare; A.K. Gupta; A.K. Saxena; K.K. Verma; O. Srivastava
RF SQUID behaviour in thin films of Tl-Ca-Ba-Cu-O has been studied. The films were prepared by the spray pyrolysis technique. Two films (A and B) which have Tc(R=0) values of 85 K and 103 K respectively, were chosen for the RF SQUID studies. Film A consists mainly of 2122 phase with needle-like grains whereas film B mainly consists of 2223 phase with well connected plate-like grains. RF SQUID modulations in film B were observed up to 101 K. The SQUID was also operated in flux-looked-loop mode. The RF SQUID fabricated from film B was found to exhibit better flux noise performance than that fabricated from film A. © 1994 IOP Publishing Ltd.
Bayes prediction results for the inverse gaussian distribution utilizing guess values of parameters
(1994) S.K. Upadhyay; R. Agrawal; U. Singh
The paper deals with the problem of predicting, on the basis of an observed sample from an inverse Gaussian distribution, a single future observation; as well as the mean of a set of future observations from the same distribution when guess values of the parameters are available. Using the general class of a prior which places a constant weight on the guess values, the paper derives the predictive p.d.f. and hence the prediction limits. The behaviour of the proposed limits as compared with the Padgett approximate classical limits [W. J. Padgett, J. Statist. Comput. Simul. 14, 291-299 (1982)] is studied using an example. The proposed limits are found to be better than the classical limits. © 1993.
Heat and Mass Transfer from Immersed Bodies to Non-Newtonian Fluids
(Academic Press, 1994) U.K. Ghosh; S.N. Upadhyay; R.P. Chhabra
[No abstract available]
Restoration strategies for the degrading Rihand River and reservoir ecosystems in India
(Elsevier Science, 1994) R.S. Ambasht; N.K. Srivastava
Water quality, phytoplankton diversity, primary production, and accumulation of N, P, K, Cd, Cu, Ni, Fe and Cr in shallow water macrophytes of the Rihand River and reservoir at Obra and Renukoot, India, were studied under the impact of effluents from a thermal power plant and chemical factory. Phytoplankton diversity and productivity were reduced under this impact. Macrophytes showed less nitrogen and phosphorus contents in the effluent-affected region, while potassium and iron content increased. Marginal herbs, Ammannia baccifera and Polygonum amphibium, accumulated high amounts of iron. It is recommended that use of harvesters of heavy metals, effective binders of soil, and conservers of nutrients be used for restoration of these wetlands. -Authors
On the electron density in an active region observed by SERTS
(Kluwer Academic Publishers, 1994) B.N. Dwivedi
Emission lines from an active region, observed by SERTS, have been used to determine electron densities from theoretical curves for Mg vii, Si viii, and Si ix density-sensitive line ratios. Density diagnostics of Al viii λ285.46/λ323.52 line emissivity ratio has also been investigated. © 1994 Kluwer Academic Publishers.
One dimensional large signal analysis for helix TWTs and multicavity klystrons
(Publ by IETE, 1994) E.V.R.Narasimha Rao; D.S. Venkateswarlu
A simple software has been developed to depict the 1-D nonlinear electron - rf wave interaction of a helix TWT using the well known disc model to work on a simple 8088 based PC system. The software has been extended to the large signal analysis of klystrons also by consideration that the interaction now is a spot interaction rather than a distributed interaction and the discs are followed in the field-free drift region. Typical results of the TWTs and multicavity klystrons, such as the Applegate diagrams, and some of the normalized parameters viz, rf voltage amplitude (A(y)) vs distance y (for a TWT), normalized fundamental rf current vs distance y (I1/I0 for the klystron) are presented. The PC simulated results (A(y) and I1/I0 for the TWT and klystron respectively) are in good agreement with those published in the literature.
Production of nitric oxide and its regulation in murine peritoneal macrophages treated with cisplatin and lipopolysaccharide
(1994) A. Sodhi; R. Kumar
Murine peritoneal macrophages treated with cisplatin or lipopolysaccharide (LPS) showed an enhanced production of nitric oxide (NO) and increased tumoricidal activity against P815 mastocytoma cells. The NO secretion and generation of macrophage-mediated tumoricidal activity were significantly inhibited by L-N-monomethyl arginine (LNMMA), a specific inhibitor of L-arginine pathway. Induction of NO production in macrophages on activation with cisplatin or LPS is inhibited by EGTA, nifedipine, TMB-8 and W-7, suggesting the probable involvement of Ca2+ and calmodulin in the induction of NO release. Protein kinase C and tyrosine kinase inhibitors significantly inhibited the cisplatin/LPS induced NO production, suggesting that phosphorylation via these kinases may up-regulate the NO synthase activity in macrophages.
Some improved estimation for common variance of two populations
(1994) B.N. Pandey; H.J. Malik
Improved estimators for common variance of two populations 2have been set up by considering that (i) s and s are the usual2estimators for estimating α and α2 respectively and (ii) the other type of estimators, are available. Comparisons in terms of mean squared error (MSE) have been made. It is shown that the proposed estimators have either smaller MSE than the usual estimators or have equivalent MSE to the minimum mean squared error (MMSE) estimator in the proposed class. © 1994, Taylor & Francis Group, LLC. All rights reserved.
Inactivation of mammalian X-chromosome during spermatogenesis: Temporal expression of genes in the laboratory mouse
(Springer India, 1994) Parimal Das; Rajiva Raman
At zygotene/pachytene stage of meiosis in mammalian testis, the X-Y heterobivalent is sequesterd into a heterochromatinized body whose genetic inactivity is shown by lack of uridine incorporation. For the genic level evaluation of the X-inactivation, activities of three X-linked genes were assayed in testicular cell types in the laboratory mouse. While hypoxanthine phosphoribosyl transferase is functional at least up to pachytene stage of primary spermatocytes, glucose-6-phosphate dehydrogenase appears to be active only in the Sertoli cells. No transcript of the muscle specific muscular dystrophin gene was obtained from its regular 5′ promoter. Thus, inactivation of X-linked genes in testis occurs at different stages during spermatogenesis, independently of heterochrornatinizati on of the XY-body. We propose that Xist transcript, the putative regulator of X-inactivation in female soma, is also the regulator in testis. However, due to its extremely low level in testis the transcript may regulate by "spreading" in a gradient and affect the genes in a temporal order. Thus, besides other factors, physical proximity of the genes to Xist may determine the stage of their inactivation. © 1994 Indian Academy of Sciences.
Relative susceptibility of two species of tropical fruit trees to thermal power plant emission
(1994) J. Singh; M. Agrawal; D. Narayan
[No abstract available]
Effects of crop growth and soil treatments on microbial C, N, and P in dry tropical arable land
(Springer-Verlag, 1994) S.C. Srivastava; J.P. Lal
We studied the dynamics of microbial C, N, and P in soil cropped with rice (Oryza sativa) and lentils (Lens culinaris) in a dryland farming system. The crop biomass and grain yield were also studied. The microbial biomass and its N and P contents were larger under the lentil than under the rice crop. Microbial nutrients decreased as the crops grew and then increased again. Farmyard manure and NPK fertilizer applications increased the level of microbial nutrients, crop biomass, and grain yield by 35-80%, 55-85%, and 74-86%, respectively. However, these applications had no significant effect on most of the soil physicochemical properties in the short term. The microbial biomass was correlated with the crop biomass and grain yield. The calculated flux of N and P through the microbial biomass ranged from 30-45 and 10-19 kg ha-1 year-1, respectively. Cultivation of a cereal crop followed by a leguminous crop sustains higher levels of microbial nutrients and hence greater fertility in impoverished tropical arable soils. The soil microbial biomass appears to contribute significantly to crop productivity by releasing nutrients, and applications of manure, either alone or with fertilizers, promote this effect more strongly than the application of NPK fertilizers alone. © 1994 Springer-Verlag.
Effect of size and shape of the allogeneic bone grafts in bridging experimental ulnar gap in rabbits.
(1994) S.K. Saraf; A. Kumar; S.M. Tuli; S. Khanna
Partially decalcified allogeneic bone matrix was cut into the sizes and shapes of cylinders, bone strips and pulverized bone powder. Large osteoperiosteal gaps were created in rabbit's ulnae. A total of 14 gaps were filled with bone strips, 20 with powder, six with cylinders and two were left unbridged to serve as control. The healing of gap was assessed at intervals with a maximum follow up of 24 weeks. Clinically at 12 weeks the bone strips could not be moved separately from each other, the whole tubular bone had also united whereas gaps filled with bone powder did not diminish in size. Radiologically union occurred earlier (around 12 weeks) in bone strips as compared to cylinders (approx-18 weeks). With bone powder only a faint line of the remnants was visible. Gross examination findings of the grafted area were in concurrence with the clinical and radiological findings. Overall the gaps filled with bone strips had 100 per cent success with early osteo induction and remodelling as compared to long cylinders whereas gaps filled with bone powder had complete failure.
Transfer RNA analysis during the reproductive cycle of a freshwater teleost, H. fossilis
(Kluwer Academic Publishers, 1994) Malancha Sarkar; P.R. Subbarayan; Manjula Vinayak
Transfer RNA was analyzed qualitatively as well as quantitatively from ovaries of the fresh water teleost Heteropneustes fossilis for twelve months. The tRNA samples were found to be pure and devoid of any high molecular weight RNA or DNA contaminations. The quantity of tRNA as well as its biological activity, assayed by in vitro aminoacylation using homologous aminoacyl tRNA synthetases, were found to be higher during resting and preparatory (pre-vitellogenic) phases, i.e. from November to March, as compared to vitellogenic and spawning phases of the fish, i.e. from April to October. The highest tRNA pool and its activity was found in the month of February, which coincides with the early preparatory phase. The results indicate that the accumulation of active tRNA starts in the resting phase. Such an accumulation of tRNA may be a part of the enrichment of mature eggs with complete translational machinery before ovulation in order to cope with the high rate of protein synthesis after fertilization. © 1994 Kluwer Academic Publishers.
Response of week old squirrel pups to melatonin and 5-methoxytryptamine injection
(Maghira and Maas Publications, 1994) C. Haldar; S. Singh
Considerable evidence indicates that methoxyindoles do influence the gonadal system in adult F.pennanti, however nothing is known about its effect in neonates. Hence, this study was planned to determine whether neonatal melatonin (aMT) and 5-methoxytryptamine (5-MT) injection can bring changes in gonad and body weight. Injection of aMT on eighth day of post-partum age, resulted in 50% decrease in body weight, while 5-MT was ineffective. Treatment with aMT and 5-MT had inhibited ovary, uterus and thyroid weight, while an increased pineal and adrenal weight was noted. Plasma aMT level increased significantly in both aMT and 5-MT treated pups, while estradiol level was very low. This suggests that aMT could not dissociate its inhibitory effect on growth as well as ovary when injected after critical period. after critical period
Relationship between soil test methods and uptake of copper and zinc by grasses on polluted soils
(1994) R.S. Singh; R.P. Singh; R.K. Rai
A study was conducted to evaluate the suitability of selected analytical methods for correlating the uptake of copper (Cu) and zinc (Zn) by grasses on soils exposed to sewage and industrial effluents and automobile exhausts. Samples of soils and selected grasses, such as Cynodon dactylon and Cyperus rotundus growing on these polluted soils, were taken and analysed for their Cu and Zn contents by extraction. Four extractants, 4M HN03, DTPA-CaCl2 (pH 7.3), IN NH40Ac (pH 4.8), and 0.001N HC1 were used. The results revealed that for the extraction of Cu and Zn from these soils, the efficiency of extraction was in the order of 4M HN03 > IN NH40Ac > DTPA-CaCl2 > 0.001N HC1. Significant positive correlationns were found between all the extracting methods and the Cu and Zn uptake by the grasses. The DTPA-CaCl2 and 0.001N HC1 extractants were found to be most promising extractants for the determination of Cu and Zn in the polluted soil in view of their high statistical relationship with the uptake of these elements by the grasses. © 1994, Taylor & Francis Group, LLC. All rights reserved.
Application of microwave remote sensing in the detection of buried objects
(Publ by IETE, 1994) P.K. Mukherjee; S.K. Sharma; K.P. Singh
The detection of buried objects by electromagnetic waves have been carried out by using active microwave remote sensor at 9.50 GHz. We have taken various objects to accommodate various degree of contrast level as far as the dielectrics and conductivities are concerned with the surrounding medium taken as sand in the present study. Measurements were performed with the help of monostatic active microwave scatterometer. Scattering measurements of buried objects were done along the x- and y-axis assuming xy-plane parallel to the surface of the earth. Calculations have been done for the values of relative amplitude from the knowledge of the back-scattered and incident signals. The original and the observed sizes and shapes of objects have been shown for comparison. The results are very encouraging as far as the detected shapes are concerned as they have been found very close to the actual objects. The role of such detection in designing microwave remote sensors as a payload for future remote sensing satellites are outlined.
Level structures in the odd-odd nucleus180Re
(Springer India, 1994) Ashok Kumar Jain; Prakash C. Sood; Raymond K. Sheline
Experimental data on energy levels of the odd-odd deformed nucleus180Re obtained from radioactive-decay and heavy-ion reaction studies are analysed to deduce spin-parity and configuration assignments for the six observed rotational bands based on the selection rules for fast beta transitions, criteria for the relative-energy ordering of the triplet and singlet bandheads, two-particle-plus-rotor model calculations including Coriolis mixing, rotational energy systematics involving staggering features, and considerations of gyromagnetic ratios, signature splittings and rotational band alignments. © 1994 the Indian Academy of Sciences.
An improved estimator for population proportion using inverse sampling
(1994) B.B. Khare; B.K. Mishra
In this paper we have proposed a method for the determination of prefixed sample size (m) used in the estimation of population proportion proposed by Haldane (1) for specified permissible error with a given confidence coefficient and an improved estimator for population proportion using inverse sampling scheme. © 1994.