Utilization of Hyperion data over Dongargarh,India, for mapping altered/weathered and clay minerals along with field spectral measurements

Hyperion data acquired over Dongargarh area, Chattisgarh (India), in December 2006 have been analysed to identify dominant mineral types present in the area, with special emphasis on mapping the altered/weathered and clay minerals present in the rocks and soils. Various advanced spectral processes such as reflectance calibration of the Hyperion data, minimum noise fraction transformation, spectral feature fitting (SFF) and spectral angle mapper (SAM) have been used for comparison/mapping in conjunction with spectra of rocks and soils that have been collected in the field using Analytical Spectral Devices's FieldSpec instrument. In this study, 40 shortwave infrared channels ranging from 2.0 to 2.4 μm were analysed mainly to identify and map the major altered/weathered and clay minerals by studying the absorption bands around the 2.2 and 2.3 μm wavelength regions. The absorption characteristics were the results of O–H stretching in the lattices of various hydrous minerals, in particular, clay minerals, constituting altered/weathered rocks and soils. SAM and SFF techniques implemented in Spectral Analyst were applied to identify the minerals present in the scene. A score of 0–1 was generated for both SAM and SFF, where a value of 1 indicated a perfect match showing the exact mineral type. Endmember spectra were matched with those of the minerals as available in the United States Geological Survey Spectral Library. Four minerals, oligoclase, rectorite, kaolinite and desert varnish, have been identified in the studied area. The SAM classifier was then applied to produce a mineral map over a subset of the Hyperion scene. The dominant lithology of the area included Dongargarh granite, Bijli rhyolite and Pitepani volcanics of Palaeo-Proterozoic age. Feldspar is one of the most dominant mineral constituents of all the above-mentioned rocks, which is highly susceptible to chemical weathering and produces various types of clay minerals. Oligoclase (a feldspar) was found in these areas where mostly rock outcrops were encountered. Kaolinite was also found mainly near exposed rocks, as it was formed due to the weathering of feldspar. Rectorite is the other clay mineral type that is observed mostly in the southern part of the studied area, where Bijli rhyolite dominates the lithology. However, the most predominant mineral type coating observed in this study is desert varnish, which is nothing but an assemblage of very fine clay minerals and forms a thin veneer on rock/soil surfaces, rendering a dark appearance to the latter. Thus, from this study, it could be inferred that Hyperion data can be well utilized to identify and map altered/weathered and clay minerals based on the study of the shape, size and position of spectral absorption features, which were otherwise absent in the signatures of the broadband sensors.     

Technical note Monitoring the Oil & Natural Gas Corporation (ONGC) oil well fire at Pasarlapudi,Andhra Pradesh,India

Methods used to infer sea surface temperatures (SSTs) from satellite have traditionally been based on regression-tuned split-window fixed-coefficient algorithms. These can give inaccurate SST results when local atmospheric conditions are significantly different from those encapsulated by the regression averaging. The new generation of SST algorithms attempts to correct for atmospheric variability. These approaches include the R₅₄ transmittance-ratio methods of other workers, and the dynamic water vapour (DWV) correction method of the authors. The relative performances of the various methods are compared by applying each to an ocean and satellite dataset obtained off the west coast of Tasmania, Australia in 1987. We also investigate the performance of the NESDIS operational multi-channel, cross-product, and nonlinear formulas for NOAA-9, -11, -12, and-14 when applied to the same dataset. We find the DWV method gives SST retrievals which have significantly smaller bias errors than those returned by the three transmittance-ratio methods. The best overall performance was returned by the NESDIS multichannel (MCSST) formula for NOAA-9, indicating that in low water vapour loading situations, the standard regression-based algorithms work well.     

Review on Metal-Filled Plastics. Part1. Electrical Conductivity

Plastic composites are members of both the oldest and the newest of materials. The first reinforced polymeric-based materials are recorded in Genesis and Exodus in the Bible as being used by the people of Babylonia and Mesopotamia around 4000–2000 B.C. These materials consisted of bitumen-based pitch for building products and bundles of papyrus reed embedded in a bitumen matrix for the construction of river boats [1]. The Hindu Vedas (written about 1000 B.C.) refers to the use of lac (a complex polymeric substance consisting of polyether and polyester chains) with fine sand for the manufacture of whetstones, which were known in India and China for several thousand years. There are a number of examples that could date back the origin of polymer composites into antiquity [1–3]. but the science of enhancing the properties of polymeric composites by the use of suitable fillers has been practiced extensively not earlier than the beginning of this century. For example, the tensile strength of polystyrene was modified by the incorporation of glass fillers only in the 1950s, half a century later than that predicted by Backeland in the early 1900s [2]. Carbon black is known to be a potential reinforcement for rubber for over 50 years. Although glass bead and glass fibers have been known for centuries, the use of these economical products in the plastic industry is relatively new [2].     

Synthesis,characterization and application of biopolymer-ionic liquid composite membranes

Biopolymer composite membranes based on chitosan doped with an ionic liquid (IL) 1-ethyl 3-methylimidazolium thiocyanate (EMImSCN) have been developed and characterized. The doped ionic liquid films show remarkable enhancement in ionic conductivity (σ). The Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and X-ray diffraction studies (XRD) affirmed the composite nature, good incorporation of ionic liquid and reduction in crystallinity of films, respectively. The interaction between ionic liquid, chitosan and iodide polymer electrolyte matrix was evaluated by cyclic voltammetry. The fabricated dye sensitized solar cell (DSSC) using this new biopolymer electrolyte membranes shows promising performance.     

On the Dempster-Shafer evidence theory and non-hierarchicalaggregation of belief structures

The Dempster's rule of combination is a widely used technique to integrate evidence collected from different sources. In this paper, it is shown that the values of certain functions defined on a family of belief structures decrease (by scale factors depending on the degree of conflict) when the belief structures are combined according to the Dempster's rule. Similar results also hold when an arbitrary belief structure is prioritized while computing the combination. Furthermore, the length of the belief-plausibility interval is decreased during a nonhierarchical aggregation of belief structures. Several types of inheritance networks are also proposed each of which allows considerable flexibility in the choice of prioritization     

A simple method for measuring the dielectric constant of solids

This paper presents a simple method for determining the dielectric constant of a solid material. The method consists of measuring the return loss due to a slab of such material inserted into a rectangular waveguide. The dielectric slab presents a discontinuity inside the waveguide, and the electric field at each interface of the slab is described as a summation of weighted sinusoidal basis functions. The scattered magnetic field on either side of the slab is determined using the modal expansion approach. These weights are solved by using the method of moments on the boundary conditions of continuity of the tangential magnetic field at the interfaces. The component of the electric field (scattered) for the dominant TE₁₀ mode can then be determined in terms of these weights, and from this result the reflection coefficient can be theoretically evaluated. A comparison between the experimentally obtained reflection/transmission coefficient and the theoretical values provide a figure for the dielectric constant of the material     

Integration of a modulated barrier photodiode with a doped-channelquasi-MISFET

An integration scheme for a front-end photoreceiver is demonstrated, wherein an identical GaAs-InGaAs-AlGaAs heterostructure is used for realizing a modulated barrier photodiode (MBP) and a doped-channel quasi-MISFET. The detectors exhibit optical gains of 200. The FETs have an extrinsic transconductance of 250 mS/mm, with f_f=12 GHz and f_max=21 GHz     

The comparative performance of some finite difference equations for transient heat conduction

The established finite difference equations to estimate one-dimensional transient heat flow in solids are the ‘classical’ form (explicit), and the Crank–Nicolson and ‘pure-implicit’ forms (both implicit). They are all based on finite difference approximation to the Fourier continuity equation. To these are now added three more explicit forms: exponential linear, exponential inverse cosine and polynomial, which are based on exact solutions to the Fourier equation. The performance of each of the six equations is tested against the exact results of a well known step excitations problem (the Groeber model). The tests consist of examining (i) finite difference errors arising from a single implementation of each form at different stages in the transient cooling process, (ii) the errors that accumulate during part or all of the cooling process (both as regards any bias that is introduced, and also a measure of variance) and (iii) the run times in executing the various forms. The nondimensional time step r was treated as the independent variable, and can be made arbitrarily large, by use of a simple time-division procedure (otherwise r < ½ for use with the classical form). It is shown that having regard to both error and run time, the polynomial form appears to be the most efficient estimator.     

High-level test generation for VLSI

The authors survey high-level approaches to test generation for VLSI circuits, which can significantly reduce test generation time while still providing good fault coverage. High-level approaches view the circuit with less structural detail, that is, from a more abstract viewpoint and often hierarchically. The authors first review some basic circuit and fault models and the two most widely known test-generation algorithms as a basis for comparison between high-level and low-level techniques. The authors then examine the more important high-level approaches, which fall into two broad classes, namely algorithmic and heuristic