Monitoring intense dust storms over the Indian region using satellite data – a case study

Dust storms are normally considered to be natural hazards. During such events, dust aerosol is loaded into the atmosphere, directly reducing visibility and effectively reflecting solar radiation back to space. In the present study, an intense dust storm was monitored during the first week of June 2010 using Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua data over the Indian region. A dust cloud was detected using a combination of MODIS reflective and emissive channels and moving trace/spread monitored by its multi-temporal data. The MODIS Terra-derived aerosol optical depth at 550 nm (AOD₅₅₀) and the aerosol index (AI) obtained from the Ozone Monitoring Instrument (OMI) were used in conjunction with National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis wind fields for the monitoring of dust clouds. The study reveals that the movement of a high concentration of dust clouds coincided with the NCEP/NCAR reanalysis meridional and zonal wind fields (>8 m s^?1) at pressure levels of 700 hPa. The Cloud–Aerosol Lidar Pathfinder Satellite Observations (CALIPSOs) that derive vertical feature mask images also suggested that the vertical extent of the dust aerosol layer was at a height of about 6 km over northern India on 2 June 2010. The roles of long-range transport of dust over the entire Gangetic plane are analysed using back trajectories from the National Oceanic and Atmospheric Administration (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Back trajectory analysis suggests that dust clouds moving over long distances entered from the western side of India on 1 June 2010.     

SCAN-speech biometric template protection based on genus-2 hyper elliptic curve

Multimedia Tools and Applications - Rapid growth in the mobile technology manifolds the usage of mobile devices. It leads to the development and popularity of mobile application in diversified...     

SNAP-compressive lossless sensitive image authentication and protection scheme based on Genus-2 hyper elliptic curve

Multimedia Tools and Applications - Hyper Elliptic Curve Cryptography (HECC) offers comparable security as that of Elliptic Curve Cryptography (ECC) even with much reduced key size. This reduction...     

Channel estimation and error correction for UWOC system with vertical non-line-of-sight channel

Recently, underwater wireless optical communication (UWOC) system has placed more attention towards increasing data rate, high accuracy, higher bandwidth and providing highly secured transmission. Generally, light propagation in underwater medium is disturbed due to some degrading effects such as turbulence, scattering and absorption which will degrade the performance. Therefore, channel estimation is essential and need to adapt suitable correction techniques that compensate the errors due to those effects. In this work, channel estimation and error correction technique are proposed for the UWOC system with vertical non-line-of-sight channel based on MIMO-OFDM approach. Initially, input sequence error is eliminated by HVD Turbo coding method and error rectified signal is modulated with M-ary OAM-PPM modulation technique. Modulated signal is transmitted through Vertical NLOS channel. During transmission, the signal undergoes scattering, absorption and channel fading. In receiver side, channel characteristics are estimated by invariant embedding method. Finally, estimated signal is demodulated and decoded by same techniques. MATLAB environment is used to implement the proposed work. Resultant performances like channel capacity, BER, SNR, data rate, receiving power and MSE for different water types like pure sea water, ocean water, costal water and turbid water are compared and results are examined.

     

A study of the performance,emission and combustion characteristics of a compression ignition engine using methyl ester of paradise oil–eucalyptus oil blends

The significance of this study is the complete replacement of diesel fuel with bio-fuels. For this purpose; bio-fuels, namely, methyl ester of paradise oil and eucalyptus oil were chosen and used as fuel in the form of blends. Various proportions of paradise oil and eucalyptus oil are prepared on a volume basis and used as fuels in a single cylinder, four-stroke DI diesel engine, to study the performance and emission characteristics of these fuels. In the present investigation a methyl ester derived from paradise oil is considered as an ignition improver. The results show a 49% reduction in smoke, 34.5% reduction in HC emissions and a 37% reduction in CO emissions for the Me50–Eu50 blend with a 2.7% increase in NO_x emission at full load. There was a 2.4% increase in brake thermal efficiency for the Me50–Eu50 blend at full load. The combustion characteristics of Me50–Eu50 blend are comparable with those of diesel.     

Performance and emission characteristics of turpentine–diesel dual fuel engine and knock suppression using water diluents

In the present work, a normal diesel engine was modified to work in a dual fuel (DF) mode with turpentine and diesel as primary and pilot fuels, respectively. The resulting homogeneous mixture was compressed to a temperature below the self‐ignition point. The pilot fuel was injected through the standard injection system and initiated the combustion in the primary‐fuel air mixture. The primary fuel (turpentine) has supplied most of the heat energy. Usually, in all DF engines, low‐cetane fuels are preferred as a primary fuel. Therefore, at higher loads these fuels start knocking and deteriorating in performances. Usually, DF operators suppress the knock by adding more pilot‐fuel quantity. But in the present work, a minimum pilot‐fuel quantity was maintained constant throughout the test and a required quantity of diluent (water) was added into the combustion at the time of knocking. The advantages of this method of knock suppression are restoration of performance at full load, maintenance of the same pilot quantity through the load range and reduction in the fuel consumption at full load. From the results, it was found that all performance and emission parameters of turpentine, except volumetric efficiency, are better than those of diesel fuel. The emissions like CO, UBHC are higher than those of the diesel baseline (DBL) and around 40–45% reduction of smoke was observed at 100% of full load. The major pollutant of diesel engine, NO_x, was found to be equal to that of DBL. From the above experiment, it was proved that approximately 80% replacement of diesel with turpentine is quite possible. Copyright © 2006 John Wiley & Sons, Ltd.     

Evolution of the intensity profile of Cerenkov second-harmonicradiation with propagation distance in planar waveguides

Using coupled mode theory, we have studied the output intensity profile of Cerenkov second-harmonic radiation from planar waveguides as a function of the propagation distance. In particular, we have obtained the variation of the intensity profile taking into account the effect of prism coupling as well as propagation loss, and have shown that the second-harmonic radiation evolves into a beam-like output. Results of the measured intensity profile of the second-harmonic radiation in proton-exchanged planar waveguides in Z-cut LiNbO₃ are also presented that are consistent with the theory     

Strategic and suave processing for performing similarity joins using MapReduce

An efficient MapReduce Algorithm for performing Similarity Joins between multisets is proposed. Filtering techniques for similarity joins minimize the number of pairs of entities joined and hence improve the efficiency of the algorithm. Multisets represent real-world data better by considering the frequency of its elements. Prior serial algorithms incorporate filtering techniques only for sets, but not multisets, while prior MapReduce algorithms do not incorporate any filtering technique or inefficiently and unscalably incorporate prefix filtering. This work extends the filtering techniques, namely the prefix, size and positional to multisets, and also achieves the challenging task of efficiently incorporating them in the shared-nothing MapReduce model, thereby minimizing the pairs generated and joined, resulting in I/O, network and computational efficiency. A technique to enhance the scalability of the algorithm is also presented as a contingency need. Algorithms are developed using Hadoop and tested using real-world Twitter data. Experimental results demonstrate unprecedented performance gain.     

Ab-initio studies of thermal and superconducting properties of HfX2 alloys (X = Tc,Re, and Os)

A systematic study of thermal properties such as the Debye temperature, specific heat coefficient, Grüneisen constant, electron-phonon coupling constant and transition temperature have been carried out using the results of electronic band structure and related characteristics, for hafnium superconducting alloys, namely, HfTc₂, HfRe₂ and HfOs₂. Computation of the electronic band structure and associated properties has been carried out using the tight-binding-linear-muffin-tin-orbital (TBLMTO) method within atomic sphere approximation (ASA). The calculated values have been compared with the available results of literature data.     

Effect of Mn substitution on structural and magnetic properties of ferromagnetic shape memory alloys

The structure and the magnetic transitions have been investigated as a function of Mn in stoichiometric Ni₂MnGa heusler alloys. Particular attention is paid to examine the linear increase of martensite transformation temperature on substituting Mn for Ga. It is observed that the martensite temperature increases and Curie temperature decreases with the effect of Mn content. Room-temperature magnetic measurements show the composition-dependent characteristics with decreasing magnetic saturation values and increasing coercivity values due to decrease in the magnetic exchange interaction strength with increasing Mn in place of Ga. The scanning electron microscopy image confirms that the Mn-rich alloys have the martensitic plates.