Complex permittivity of soil and water mixtures at 9 GHz

Measurements of the complex permittivity of many soil samples were conducted using the evanescent waveguide technique at 9 GHz. The complex permittivity was taken as a function of moisture content. The experimental results were interpreted using Wiener's theory for dielectric mixtures to evaluate the degree of binding of water in soils.     

Extending the bandwidth of an instrumentation amplifier

A new configuration for operational amplifier based instrumentation amplifier is presented. The analytical expressions are obtained and the performance of the proposed circuit is examined in relation to the conventional circuit. Simulation and experimental results are presented which establish the superiority of the proposed instrumentation amplifier topology over the conventional circuit. The effect of second pole of op amps on the circuit stability has also been investigated. Numerical results are given in support of theoretical conclusions.     

ANTIOXIDANT POTENTIAL OF ORAL FEEDING OF CYNODON DACTYLON EXTRACT ON DIABETES-INDUCED OXIDATIVE STRESS

The present study is an extension of our previous research work and it deals with the scientific evaluation of antioxidant potential of the aqueous extract of Cynodon dactylon on diabetes-induced oxidative stress of diabetic rats. The most effective dose of 500 mg/kg of extract was given orally to diabetic rats for 30 days. Different oxidative stress parameters were analyzed in various tissues of control and treated diabetic rats. The observed elevated level of LPO comes down significantly ( P <  0.05), and decreased activities of antioxidant enzymes such as CAT, SOD, GPx and GST got increased ( P <  0.05) significantly in diabetic rats on extract treatment. The flavonoids present in the aqueous extract of this plant might be responsible for its marked antioxidant efficacy at tissue level in STZ-induced diabetic rats.

PRACTICAL APPLICATIONS

The Cynodon dactylon has been shown to possess varied medicinal properties. The aqueous extract of the rhizome is used as anti-inflammatory, diuretic, antiemetic, antidiabetic and blood-purifying agent. Recently, it has been reported by our research group that the extract of C. dactylon has hypoglycemic as well as antidiabetic potential. The present communication is an endeavor in the direction of evaluating its in vivo antioxidant effect in STZ-induced diabetic rats so that it can be used as a value-added agent for managing diabetes as well as oxidative stress associated with it.     

On Graphical Studies of PEN-IM Sets of Boolean Functions and their Minimizations. Part I†

The graphs of the sets of all penultimate implicants of certain types of Boolean functions are obtained in this part of the paper. Identification of different C.H. Boolean functions with their graphs are then made and terms are coined to designate these functions for the easy pattern recognition of their graphs. Finally formulae are deduced which give the number of prime implicants that must be present in any minimal cover of these functions.     

Effect of anodization on corrosion behaviour and biocompatibility of Cp-titanium in simulated body fluid

The objective of this investigation is to study the effectiveness of anodized surface of commercial purity titanium (Cp-Ti) on its corrosion behaviour in simulated body fluid (SBF) and proliferation of osteoblast cells on it, to assess its potentiality as a process of surface modification in enhancing corrosion resistance and osseointegration of dental implants. Highly ordered nano-porous oxide layer, with nano-sized pores, is developed on the surface of Cp-Ti through electrochemical anodization in the electrolyte of aqueous solution of 0·5% HF at 15 V for 30 min at 24 °C. The nano-porous feature of the anodized surface is characterized by field-emission scanning electron microscope (FESEM). Pores of some anodized samples are sealed by exposing the anodized surface in boiling water. Corrosion behaviour of the anodized specimen is studied in Ringer’s solution at 30 ± 2 °C, using electrochemical impedance and cyclic polarization technique. Biocompatibility of the anodized surface is accessed using MG63 osteoblast cells. Both corrosion as well as pitting resistance of Cp-Ti in simulated body fluid are found to be highest in the anodized and sealed condition and followed in decreasing order by those of anodized and unanodized ones. Significantly higher MG63 osteoblast cell proliferations are found on the anodized surface than that on the unanodized one. Anodized Cp-Ti develops nano-size surface pores, like that of natural bone. It enhances corrosion and pitting resistance and also the process of osteoblast cell proliferation on Cp-Ti.     

Switched-capacitor filters using unity-gain amplifiers

Switched-capacitor networks realizing second-order filter characteristics are presented. Realization is achieved with unity-gain amplifiers as buffers. The circuits have small sensitivities, good dynamic range and a reasonable spread of capacitor values. The filters can be used for high-Q realization and a relatively high frequency range.     

Urban growth trend analysis using GIS techniques—a case study of the Bombay metropolitan region

Abstract

Towns and cities in India are facing complex problems regarding the provision and maintenance of services and infrastructure in the face of the rapid growth of pupulation, caused both by natural increase and migration. In order to meet such challenges a planner needs to have fairly accurate and up-to-date information, especially about physical structures and related land parameters. A study of their trends generally helps in the understanding of the emerging growth pattern and in formulating policies to guide or redirect it. Recent advances in the field of remote sensing technology and computer based Geographical Information Systems (GIS) provide very useful tools in undertaking such analysis. The results from a study about growth trends of the urban areas in the Bombay Metropolitan Region using multi-date remote sensing data and ARC/INFO GIS package are described here. The period under consideration is from 1968 to 1989. It should be noted that the major growth in the region is confined to Greater Bombay between 1968 to 1975. After the year 1975, a distinct outward growth along the rail corridors is visible. Growth after 1975 is mainly in the Kalyan, Bhiwandi, New Bombay and Panvel areas and in the area around Manori creek (Charkop area). The growth rate is found to be higher after the year 1975 compared to the prior growth rate. The spatial growth trends are examined in relation to the population and the population density has been computed for different periods. Based upon these densities, the extent of land required for urban development for the year 2001 has been calculated. Suitability of land for urbanisation has been carried out based upon physical characteristics of the land and environmental parameters. The priority areas of urban development to meet the additional requirement in 2001 have been identified on the basis of this suitability analysis. A map on a 1:250000 scale has been prepared to show the areas for urbanisation which will meet the demands for the year 2001. This study demonstrates the potential offered by the integration of the tools of remote sensing and GIS for urban and regional planning.     

A new semi-empirical sea spectrum for estimating the scattering coefficient

A large data base comprising SEASAT A satellite scatterometer measurements and quasi-concurrent high quality sea wind data, as represented by Britt and Schroeder (1984) in the form of a multivariate regression, has been used to tune the overall magnitude of the assumed sea spectrum by inverting the two scale scattering theory. Scattering coefficient values computed for the derived spectrum have been compared with those computed for the spectrum suggested by earlier authors, and an improvement is found in the surface wind-scattering coefficient relationship as verified by comparison with the independent AAFE RADSCAT data set.