Remote-sensing and GIS-based landslide-susceptibility zonation using the landslide index method in Igo River Basin,Eastern Himalaya,India

A remote-sensing and geographical information sysytem (GIS)-based quantitative methodology for landslide-susceptibility zonation is described in a stepwise manner with its application in the Igo River Basin in the West Siang District of Arunachal Pradesh, Eastern Himalaya, India. Parameters such as geology, physiography, slope angle, slope length, slope aspect, slope type, generic landforms, lineament distance, road distance, drainage distance, altitudinal zones and land cover are used for landslide-susceptibility zonation. The quantitative relation between landslides and the selected parameters is established through the landslide index method of the International Institute for Geo-Information Science and Earth Observation (ITC), The Netherlands, by assigning weights. A weight value for a certain parameter class is defined as the natural logarithm of the landslide density in the class divided by the landslide density in the entire map. The final layer containing the composite index is divided into seven landslide-susceptibility categories. The maximum portion of the study area experiences moderately low to moderate landslide susceptibility, and each portion occupies an area of 91 km², representing 30% of the total area. High concentrations of very high and extremely high-susceptibility landslide areas are noticed in the steep slope areas, especially in the Sub-Himalayas. The settlements are found in the safe areas of very low, low and moderately low landslide-susceptibility categories. About 9% and 1.99% of the roads are exposed to high and very high landslide-susceptibility areas, respectively. About 15% of the slash-and-burn cultivation (jhum) is found along the high-susceptibility areas, 3.89% is found in very high-susceptibility areas and 0.19% is prone to extremely high susceptibility. The high-susceptibility zones are also found under dense and moderately dense forests.     

Modeling of wideband radio frequency power amplifiers using Zernike polynomials

In this article, we suggest a new set of basis functions that are based on Zernike polynomials for the behavioral modeling of radio frequency power amplifiers (PAs). The modeling of highly nonlinear PAs exhibits numerical instability that degrades the accuracy of the model parameters and predistorter modeling efficiency. Simulation results show that the proposed polynomial model is more suitable to resolve the numerical instability problem and proves to have greater accuracy with reduced complexity. A Doherty PA driven by a multicarrier wideband code division multiple access signal was used for validation; and, the obtained results show that the new model exhibits superior numerical stability as the nonlinearity order and memory depth of the model increase. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

Structural,dielectric and ferroelectric properties of Ba1−x(Bi0.5Na0.5)xTiO3 ceramics

Lead free Ba_1?x(Bi_0.5Na_0.5)_xTiO₃ (x=0, 0.02, 0.04, 0.06, 0.08, 0.1) ferroelectric ceramics were synthesized by conventional solid state reaction technique. Sintering was done at 1200 °C for 2 h in air atmosphere. The final products have tetragonal symmetry with decreasing c/a ratio confirmed by X-ray diffraction analysis. The grain size varies between 300 nm to 1000 nm for x=0 to 0.1. With increase in Bi_0.5Na_0.5TiO₃ [BNT] content, the room temperature permittivity decreases whereas the Curie temperature (T_c) increases and its highest value was found to be 155 °C for 10 mol% of BNT addition. The ceramics show stable and low dielectric loss characteristics. The remnant polarization (P_r) and the coercive field (E_c) increases monotonously with increase in BNT content. The highest value of 2P_r (=17 μC/cm²) and 2E_c (=22 Kv/cm) was obtained for x=10 mol% BNT addition.     

Grafting onto wool. XXIII. Graft copolymerization of methyl methacrylate by use of chromium acetyl acetonate–perchloric acid system: Effect of tertiary butyl hydroperoxide

Methyl methacrylate (MMA) has been graft copolymerized onto Himachali wool in an aqueous medium by using chromium acetyl acetonate in the presence of perchloric acid at 45, 55, 65, and 75°C for various reaction periods. Percentage of grafting has been determined as functions of various reaction variables. Tertiary butyl hydroperoxide (TBHP) was found to influence grafting of MMA. Rate of grafting (R_p) and induction period (I_p) of MMA towards graft copolymerization were determined as function of total initial monomer concentrations. In the absence of TBHP, R_p does not change markedly with the increase in monomer concentration. When the graft copolymerization was carried out in the presence of TBHP, an increase in R_p and a decrease in I_p were observed.     

Use of initial rise method to analyze a general-order kinetic thermoluminescence glow curve

The application of the initial rise method, in the case of the general-order kinetics of thermoluminescence, has so far been limited to finding the thermal activation energy. However, the order of kinetics and pre-exponential factors could not be evaluated using this method so one has to resort to other methods of glow curve analysis. In the present paper, a novel method is suggested to calculate the kinetic order and the pre-exponential factor from the Arrhenius plots of the initial rise part of the thermoluminescence glow curve. The method uses the intercept values on the thermoluminescence intensity axis of the Arrhenius plots at two or more known doses to evaluate the value of kinetic order.     

A study of physicochemical characteristics of respirable dust in an Indian coal mine

The respirable coal dust samples were collected from the mine atmosphere during drilling of coal seams using ‘Hexlet’ apparatus. Sixteen dust samples were collected from each three different seams for investigations. After destruction of the organic matter by wet oxidation and filtering off the clay and silica, Fe, Ca, Mg, Na, K, Mn, Zn, Cu, Cd and Ni were determined directly in the resulting solution by atomic absorption spectrophotometric methods. The x-ray diffraction studies have shown the presence of kaolinite, quartz, pirrsonite, and beidellite clay minerals in the coal dust.The mass-size distribution of the coal dust has been studied by using micron photosizer. The results showed that the distribution are unimodal, asymmetric, and positively skew. Although the assumption of log-normality was useful in interpreting the results, closer observations indicated that the relationship between the size and weight of the particles can be represented by a second degree parabolic equation W = a + bS + cS², where W and S are weight and size of the particles and a, b and c are constants. This equation helps us to characterise the mass of the respirable particles if the size is known.The studies throw light on the nature and mode of trace elements found in Indian Coal as well as on the causes of respiratory disease, pneumoconiosis, affecting the workers in the mine environmental condition.     

Surface distortion features on indented CaF2 cleavages

Surface distortion features around static indents on the cleavages of CaF₂ single crystals have been investigated by multiple beam interference technique. At room temperature microcracks around such indents nucleate at the sinking in regions. Fizeau fringe patterns (around indents at 200° C) revealed a transition from a three-fold to a six-fold material flow.     

Study of solvents for butadiene extraction by gas chromatography

Six solvents have been studied by GLC for separation of 1,3-butadiene from C₄-olefins having close boiling points. Infinite dilution activity coefficients and partition coefficients of five olefins have been determined in these solvents by conventional GLC-technique at 30 °C. Relative volatilities of olefins in solvents have been calculated and on this basis the solvents have been compared.     

Effects of maternal ethanol consumption on hepatic lipid biosynthesis in foetal and neonatal rats

Effects of prolonged maternal ethanol consumption were studied on hepatic lipid content, on the rates of fatty acid synthesis and on the activities of enzymes involved in fatty acid synthesis in the livers of foetal and suckling neonatal rats. Prolonged maternal ethanol consumption resulted in a significant increase in the contents of hepatic total lipids, triacylglycerols and plasma unesterified fatty acids in foetal and neonatal rats. Studies in vitro with 3H2O showed that maternal ethanol consumption did not result in a significant change in its rate of incorporation into lipid fractions of foetal and neonatal livers. The rates of fatty acid synthesis showed a pronounced decrease immediately after birth, compared with the foetal stage, but increased in the adult animals. On the other hand, the highest rates of lipid oxidation were observed in the neonatal stage. Maternal ethanol consumption resulted in a significant decrease in the rates of [14C]palmitate oxidation to 14CO2 by both the foetal and neonatal livers. Maternal ethanol consumption did not result in an increase in the activities of any of the lipid-synthesizing enzymes tested throughout the period of development. Although increased fatty acid synthesis does not seem to be the mechanism for the accumulation of these lipids, decreased oxidation of the lipids may be partly responsible for the lipid accumulation.     

Study of a chemically amplified resist for X-ray lithography by Fourier transform infrared spectroscopy

Future applications of microelectromechanical systems (MEMS) require lithographic performance of very high aspect ratio. Chemically amplified resists (CARs) such as the negative tone commercial SU-8 provide critical advantages in sensitivity, resolution, and process efficiency in deep ultraviolet, electron-beam, and X-ray lithographies (XRLs), which result in a very high aspect ratio. In this investigation, an SU-8 resist was characterized and optimized for X-ray lithographic applications by studying the cross-linking process of the resist under different conditions of resist thickness and X-ray exposure dose. The exposure dose of soft X-ray (SXR) irradiation at the average weighted wavelength of 1.20 nm from a plasma focus device ranges from 100 to 1600 mJ/cm(2) on the resist surface. Resist thickness varies from 3.5 to 15 mum. The cross-linking process of the resist during post-exposure bake (PEB) was accurately monitored using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 862, 914, 972, and 1128 cm(-1) in the spectrum of the SU-8 resist were found to be useful indicators for the completion of cross-linking in the resist. Results of the experiments showed that the cross-linking of SU-8 was optimized at the exposure dose of 800 mJ/cm(2) for resist thicknesses of 3.5, 9.5, and 15 microm. PEB temperature was set at 95 degrees C and time at 3 min. The resist thickness was measured using interference patterns in the FT-IR spectra of the resist. Test structures with an aspect ratio 3:1 on 10 microm thick SU-8 resist film were obtained using scanning electron microscopy (SEM).