319 research outputs found

    NASA Thesaurus in Information Retrieval

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    A brief account of the NASA Thesaurus is presented. Some typical problems encounted in information search using the subject indexes to the Scientific and Technical Aerospace REports (STAR) and International Aerospace Abstracts which are compiled using NASA Thesaurus, are mentioned. Use of facet analysis and synthesis based on S R Ranganathan's subject structure model is recommended for use along with the thesaurus to secure precise and consistent search formulation for compound subjects

    Ni/H-ZSM-5 as a stable and promising catalyst for COx free H2 production by CH4 decomposition

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    Catalytic decomposition of methane for COx free hydrogen production is carried out over Ni supported on H-ZSM-5 catalysts with different Si/Al ratios (i.e. 40, 150, 300 and 485) at 550 °C and atmospheric pressure. Methane decomposition activity of Ni/H-ZSM-5 is decreased with time on stream and finally deactivated completely. The fresh and reduced catalysts are characterized by BET-SA, XRD, FT-IR, UV-DRS, TPR, pulse chemisorption of H2 and N2O and some of the used catalysts are characterised by CHNS, SEM, TEM and Raman spectroscopy. Raman spectra of the used catalysts showed both ordered and disordered carbon at 1580 cm-1 and 1320 cm-1. The 20 wt% Ni/H-ZSM-5 (Si/Al = 150) exhibited a higher H2 production rate over the other Ni loadings. The superior performance of 20 wt% Ni/H-ZSM-5 (Si/Al = 150) is rationalized by the physico-chemical properties of the various Ni loaded H-ZSM-5 catalysts

    Growth Kinetics of Zr-4 in Sodium Bisulphite: Solvent Studies

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    Abstract: Anodization of zircaloy-4 in 0.1 M sodium bisulphite has been carried out. Kinetics of anodic oxidation of zircaloy-4 has been studied at a constant current density of 8 mA.cm -2 and at room temperature. The plots of formation voltage vs. time, reciprocal capacitance vs. time and reciprocal capacitance vs. formation voltage were drawn. From these plots, formation rate, current efficiency and differential field were calculated. The addition of solvent (Ethylene glycol) showed better kinetic results. For 20, 40, 60 and 80% aquo-glycolic media, the dielectric constant values are low leading to the marked improvement in the kinetics

    An index based road feature extraction from LANDSAT-8 OLI images

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    Road feature extraction from the remote sensing images is an arduous task and has a significant role in various applications of urban planning, updating the maps, traffic management, etc. In this paper, a new band combination (B652) to form a road index (RI) from OLI multispectral bands based on the spectral reflectance of asphalt, is presented for road feature extraction. The B652 is converted to road index by normalization. The morphological operators (top-hat or bottom-hat) uses on RI to enhance the roads. To sharpen the edges and for better discrimination of features, shock square filter (SSF), is proposed. Then, an iterative adaptive threshold (IAT) based online search with variational min-max and Markov random fields (MRF) model are used on the SSF image to segment the roads and non-roads. The roads are extracting by using the rules based on the connected component analysis. IAT and MRF model segmentation methods prove the proposed index (RI) able to extract road features productively. The proposed methodology is a combination of saturation based adaptive thresholding and morphology (SATM), and saturation based MRF (SMRF), applied to OLI images of several urban cities of India, producing the satisfactory results. The experimental results with the quantitative analysis presented in the paper

    Thermal Stability and Antibacterial Activity of a Newly Prepared Organic Coating from a De-saturated Seed Oil of Thevetia Peruviana

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    Air drying polyesteramide-urethanes resins were synthesized from de-saturated fatty methyl ester (FAME) of Thevetia peruviana seed oil commonly known as Yellow oleanda (a tropical ornamental shrub) having about 68.8% unsaturated and 30.9% saturated fatty acids. Urea fractionation method was used to optimize the percentage of functional groups (in this case double bonds) by physio-sorption of the saturated fatty acids. The physico-chemical characterization of the optimized unsaturated FAME such as hydroxyl value, iodine value, saponification value, refractive index, inherent viscosity were carried out using standard methods. Through condensation reaction the N,N- bis(2-hydroxyethyl) Thevetia peruviana (HETA) prepared from the FAME react with isophthalic acid to form polyesteramide. The latter undergo urethanation with H1 • 2 MDI. The structural elucidation of the moisture cured polyesteramide-urethane urethane coating was based on FTIR, 1H-NMR and 13C-NMR spectroscopic methods. The coatings films were evaluated for its antibacterial activity and thermal stability properties on TGA and DSC. SEM of the coating films was also examine

    Development of Poly (Ester Amide-Urethanes) from De-saturated Thevetia peruviana Seed Oil-FAMEs

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    This study present the synthesis of eco-friendly poly(ester amide-urethane) coating from Thevetia peruviana seed oil (TPSO). FT-IR, 1H NMR and 13C NMR spectral analyses were used in confirming the structure of compounds. Physico-chemical properties of desaturated N,N'-bis (2- hydroxyethyl) Thevetia peruviana seed oil fatty amide (DHETA), poly(ester amide) (PESA) and poly(ester amide urethanes) (PESAU), as well as chemical resistance, antibacterial studies and thermal analysis of PESAU were also examined. Aims: To evaluate the thermal stability and antibacterial activities of PESAU. Study Design: Extraction of seed oil from the air-dried seedlings of Thevetia peruviana seeds and preparation of polyol through urea fractionation. Followed by urethane synthesis using 4,4'- diisocyanatodicyclohexylmethane (H12MDI). Result: The 46.4 g ICI/100g Iodine value (I.V.) of the amide (DHETA) base polyol was reduced to 10.5 g ICI/100 g value for the urethane (PESAU). The zero percent value for PESAU hydroxyl value (H.V.) is an indication of complete reaction of the hydroxyl functional groups on PESA with H12MDI. Spectroscopic examinations carried out confirm the formation of synthesized compounds. Conclusion: The synthesized urethane (PESAU) shows excellent inhibitive activities against tested organisms

    Reusable Multi-Stage Multi-Secret Sharing Schemes Based on CRT

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    Three secret sharing schemes that use the Mignotte’ssequence and two secret sharing schemes that use the Asmuth-Bloom sequence are proposed in this paper. All these five secret sharing schemes are based on Chinese Remainder Theorem (CRT) [8]. The first scheme that uses the Mignotte’s sequence is a single secret scheme; the second one is an extension of the first one to Multi-secret sharing scheme. The third scheme is again for the case of multi-secrets but it is an improvement over the second scheme in the sense that it reduces the number of publicvalues. The first scheme that uses the Asmuth-Bloom sequence is designed for the case of a single secret and the second one is an extension of the first scheme to the case of multi-secrets. Novelty of the proposed schemes is that the shares of the participants are reusable i.e. same shares are applicable even with a new secret. Also only one share needs to be kept by each participant even for the muslti-secret sharing scheme. Further, the schemes are capable of verifying the honesty of the participants including the dealer. Correctness of the proposed schemes is discussed and show that the proposed schemes are computationally secure

    Air Quality Modeling for the Urban Jackson, Mississippi Region Using a High Resolution WRF/Chem Model

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    In this study, an attempt was made to simulate the air quality with reference to ozone over the Jackson (Mississippi) region using an online WRF/Chem (Weather Research and Forecasting–Chemistry) model. The WRF/Chem model has the advantages of the integration of the meteorological and chemistry modules with the same computational grid and same physical parameterizations and includes the feedback between the atmospheric chemistry and physical processes. The model was designed to have three nested domains with the inner-most domain covering the study region with a resolution of 1 km. The model was integrated for 48 hours continuously starting from 0000 UTC of 6 June 2006 and the evolution of surface ozone and other precursor pollutants were analyzed. The model simulated atmospheric flow fields and distributions of NO2 and O3 were evaluated for each of the three different time periods. The GIS based spatial distribution maps for ozone, its precursors NO, NO2, CO and HONO and the back trajectories indicate that all the mobile sources in Jackson, Ridgeland and Madison contributing significantly for their formation. The present study demonstrates the applicability of WRF/Chem model to generate quantitative information at high spatial and temporal resolution for the development of decision support systems for air quality regulatory agencies and health administrators

    PAN SHARPENING USING RELATIVE SPECTRAL RESPONSE OF SENSOR FOR CARTOSAT-1 PAN AND RESOURCESAT LISS-4 MX DATA

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    Most of the Indian remote sensing systems, provide sensors with one high spatial resolution panchromatic (PAN) and several multispectral (MS) bands. An increasing number of applications, such as feature detection, change monitoring, and land cover classification, often demand the use of images with both high spatial and high spectral resolution. Image fusion or pan sharpening, is a technique to enhance the spatial resolution. The most significant problem in the traditional fusion methods is spectral distortion of fused images. The main reason for this being, the physical spectral characteristic of the sensors are not considered during the fusion process, resulting in undesirable effects such as modified spectral signatures resulting in classification errors and resolution over injection. For most earth resource satellites which provide both PAN and MS bands, in ideal condition, all MS bands would be well separated and would cover exactly the same wavelengths as the PAN band. Theoretically, the measured energy in the PAN band can be obtained with the summation of corresponding MS bands. As the measured energy in an individual channel is the sum of incoming radiation and relative spectral response: Lk&thinsp;=&thinsp;L(&lambda;)&thinsp;Rk(&lambda;); where &lambda; is the wavelength, the in-band radiance, L(&lambda;) at aperture spectral radiance and Rk(&lambda;) the peak-normalized spectral response. Therefore, the energy in PAN band can be estimated by defining weights as follows: Pan&thinsp;=&thinsp;wR&thinsp;R&thinsp;+&thinsp;wG&thinsp;G&thinsp;+&thinsp;wNIR NIR&thinsp;+ other; where Pan, G, R, NIR represent the radiance of individual spectral bands wG, wR, wNIR are the weights of corresponding MS bands and other for the influence of the spectral range which is missing from MS bands but still covered with the PAN band. In this paper, a novel spectral preservation fusion method for remotely sensed images using Cartosat-1 PAN and Resourcesat-Liss4 Mx data is presented by considering the physical characteristics of the sensors. It is based on the curvelet transform using relative spectral response (RSR) values of the sensor, improved in two parts: 1) the construction of PAN image using RSR values and the curvelet components, 2) the injection method of detail information. The performance and efficiency of the proposed method is compared with traditional IHS, wavelet based methods both visually and quantitatively. The results show that the proposed method preserves spatial details and minimize spectral distortion.</p
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