Optimal estimation of interferometric phase for measuring surface deformation

In recent times, time-series interferometric synthetic aperture radar (InSAR) methods are developed to retrieve the deformation signal in non-urban areas from distributed scatterers (DS). Phase triangulation algorithm (PTA), an important step in these methods for filtering decorrelation noise from DS, aims at optimal estimation of the filtered wrapped interferometric phase values using InSAR data stack. The uniqueness of this research work lies in the incorporation of one such PTA only to provide an optimal set of wrapped interferometric phase values before phase unwrapping in the open source StaMPS processing environment. The proposed methodology, when adapted to measure surface deformation in Tehri reservoir rim region, Uttarakhand, India using Environmental Satellite (Envisat) C-band advanced synthetic aperture radar images, works efficiently and has enhanced the spatial coverage of measurement pixels compared to standalone PS-InSAR processing. It is also revealed from the one-dimension-line of sight velocity map that resulted velocity estimates are congruent with standalone PS-InSAR processing.     

WEAKEST LINK,OR…

Metaphorizing is the principal means with which to conduct our thinking. We use metaphors to make meaning and sense about the world around us. We use them, furthermore, to form a view on the nature of the subject of the study. Thus, they play an important role in understanding a subject. Our point of view will determine what insights we will make and what inferences we draw. It is essential to understand the meaning of the metaphor and what mental pictures—including unintended ones—it conveys. Using an inappropriate mental picture can cause serious misconceptions. The focal point of this article is metaphors used to describe information security. The first one is a commonly used metaphor in the information security industry—the link metaphor. The meaning and the problems evident with using this metaphor are discussed first. An alternative is then provided—the Formula 1 (F1) car metaphor. A detailed rationale for using this metaphor instead of the first one completes the article.     

Fully embedded board-level guided-wave optoelectronic interconnects

A fully embedded board-level guided-wave optical interconnection is presented to solve the packaging compatibility problem. All elements involved in providing high-speed optical communications within one board are demonstrated. Experimental results on a 12-channel linear array of thin-film polyimide waveguides, vertical-cavity surface-emitting lasers (VCSELs) (42 μm), and silicon MSM photodetectors (10 μm) suitable for a fully embedded implementation are provided. Two types of waveguide couplers, titled gratings and 45° total internal reflection mirrors, are fabricated within the polyimide waveguides. Thirty-five to near 100% coupling efficiencies are experimentally confirmed. By doing so, all the real estate of the PC board surface are occupied by electronics, and therefore one only observes the performance enhancement due to the employment of optical interconnection but does not worry about the interface problem between electronic and optoelectronic components unlike conventional approaches. A high speed 1-48 optical clock signal distribution network for Cray T-90 super computer is demonstrated. A waveguide propagation loss of 0.21 dB/cm at 850 nm was experimentally confirmed for the 1-48 clock signal distribution and for point-to-point interconnects. The feasibility of using polyimide as the interlayer dielectric material to form hybrid three-dimensional interconnects is also demonstrated. Finally, a waveguide bus architecture is presented, which provides a realistic bidirectional broadcasting transmission of optical signals. Such a structure is equivalent to such IEEE standard bus protocols as VME bus and FutureBus     

Iterative weighted EM and iterative weighted EM′-index for scientific assessment of scholars

Scientometrics - In the field of scientific assessment of scholars, there were several metrics has been given by the scholars. From the list of indices, the h-index is widely accepted for the...     

Correction to: EM-index: a new measure to evaluate the scientific impact of scientists

Scientometrics - In the original publication, Acknowledgements was published with incomplete information. The complete Acknowledgements is given in this correction.     

Fast algorithm for chirp transforms with zooming-in ability and its applications

A general fast numerical algorithm for chirp transforms is developed by using two fast Fourier transforms and employing an analytical kernel. This new algorithm unifies the calculations of arbitrary real-order fractional Fourier transforms and Fresnel diffraction. Its computational complexity is better than a fast convolution method using Fourier transforms. Furthermore, one can freely choose the sampling resolutions in both x and u space and zoom in on any portion of the data of interest. Computational results are compared with analytical ones. The errors are essentially limited by the accuracy of the fast Fourier transforms and are higher than the order 10(-12) for most cases. As an example of its application to scalar diffraction, this algorithm can be used to calculate near-field patterns directly behind the aperture, 0 < or = z < d2/lambda. It compensates another algorithm for Fresnel diffraction that is limited to z > d2/lambdaN [J. Opt. Soc. Am. A 15, 2111 (1998)]. Experimental results from waveguide-output microcoupler diffraction are in good agreement with the calculations.     

Respiratory health problems associated to infrastructural development among residents living near Special Economic Zone in India

A cross-sectional study was undertaken to assess the lung function status of residents living in areas adjacent to Noida Special Economic Zone (NSEZ). The survey included 161 subjects (Bhangal = 79, Bakhtiyarpur = 48, and Hazipur = 34) and 104 subjects from a non-industrial zone. The study showed a significantly high prevalence of lung function impairment (17.7%) amongst residents living adjacent to Special Economic Zone (Bhangal) compared with residents of non-industrial zone. Breathlessness and cough was more prevalent amongst residents of Bhangal. It was found that lung function deficits amongst residents and distance from NSEZ were inversely related. Lung function abnormalities were found to be at maximum in Bhangal at 1-km distance, moderate in Hazipur at 2-km distance and minimum in Bhaktiyarpur at 3-km distance. At all three locations adjacent to NSEZ, particulate matter (PM) concentration showed suspended particulate matter (SPM) and respirable suspended particulate matter (RSPM) above the prescribed limits of national ambient air quality standard; concentration of PM with an aerodynamic diameter ≤ 2.5 μm (PM_2.5) and PM with an aerodynamic diameter ≤ 1 μm (PM₁) was also higher than the control area. Construction activities related to infrastructural development and increased vehicular traffic may be responsible for higher concentrations of PM_2.5, PM₁, RSPM and SPM in these areas.     

Optimized dispersion of nanoparticles for biological in vitro and in vivo studies

Background

The aim of this study was to establish and validate a practical method to disperse nanoparticles in physiological solutions for biological in vitro and in vivo studies.

Results

TiO₂ (rutile) dispersions were prepared in distilled water, PBS, or RPMI 1640 cell culture medium. Different ultrasound energies, various dispersion stabilizers (human, bovine, and mouse serum albumin, Tween 80, and mouse serum), various concentrations of stabilizers, and different sequences of preparation steps were applied. The size distribution of dispersed nanoparticles was analyzed by dynamic light scattering and zeta potential was measured using phase analysis light scattering. Nanoparticle size was also verified by transmission electron microscopy. A specific ultrasound energy of 4.2 × 10⁵ kJ/m³ was sufficient to disaggregate TiO₂ (rutile) nanoparticles, whereas higher energy input did not further improve size reduction. The optimal sequence was first to sonicate the nanoparticles in water, then to add dispersion stabilizers, and finally to add buffered salt solution to the dispersion. The formation of coarse TiO₂ (rutile) agglomerates in PBS or RPMI was prevented by addition of 1.5 mg/ml of human, bovine or mouse serum albumin, or mouse serum. The required concentration of albumin to stabilize the nanoparticle dispersion depended on the concentration of the nanoparticles in the dispersion. TiO₂ (rutile) particle dispersions at a concentration lower than 0.2 mg/ml could be stabilized by the addition of 1.5 mg/ml albumin. TiO₂ (rutile) particle dispersions prepared by this method were stable for up to at least 1 week. This method was suitable for preparing dispersions without coarse agglomerates (average diameter < 290 nm) from nanosized TiO₂ (rutile), ZnO, Ag, SiO_x, SWNT, MWNT, and diesel SRM2975 particulate matter.

Conclusion

The optimized dispersion method presented here appears to be effective and practicable for preparing dispersions of nanoparticles in physiological solutions without creating coarse agglomerates.     

Priority based efficient data scheduling technique for VANETs

As vehicular networks are gaining popularity, large number of vehicles want to take advantage of these networks, by utilizing the information they have, in order to take decision. Vehicle receives data from other vehicles or from the road side units (RSUs) available across the road. Since RSUs act as router to connect with the external world as well as it is a high capacity storage place where important data (e.g. data used in traffic safety, location dependent query, etc.) can be stored for download purpose for other vehicles moving through the service area. Since the RSUs have limited communication range and vehicles usually moves at very high speed in the service area, they have limited time to serve data to vehicles moving in the service area. For this purpose RSUs have to schedule data in such a way that maximum vehicles can get benefit from the data available with the RSUs. There are many algorithms proposed in the past to schedule data at RSUs. This paper proposes a mechanism to schedule data of those vehicles which are in the coverage range of the RSU. The proposed algorithm outperforms to serve requests whose deadline is about to expire i.e. vehicles which have left the service area after forwarding request to RSU. This scheme performs well in dense network and has good results in highway scenario.     

Effect of thermal pretreatment on recovery of nickel and cobalt from Sukinda lateritic nickel ore using microorganisms

Experimental investigation made previously on microbiological leaching of nickel and cobalt from the laterite nickel ore of Sukinda Valley reveals that the recovery was not very much promising under any favorable conditions. Therefore, in order to improve the efficiency for bioleaching, the homogenized lateritic ore in palletized form is thermally pretreated by roasting at different temperatures. The parameters studied for the bioleaching experiments were the four types of pretreated ore which were roasted at different temperatures, i.e., 300 °C, 400 °C, 600 °C and 800 °C, in shake flask by using a mixed mesophilic acidophilic bacterial consortium consisting predominantly of the Acidithiobacillus ferrooxidans strain. It was observed that the pretreated ore at 600 °C with 10% (w/v) pulp density showed maximum recovery of nickel and cobalt, i.e., 59.18% (4.556 ppm) and 65.09% (0.546 ppm), using 10% (v/v) (2.5 × 10⁸ cells/ml) consortium concentration at 1.5 pH, 30 °C, and 150 rpm after an incubation period of 31 days.