SAR interferometry in post-seismic ground deformation detection related to the 2001 Bhuj earthquake,India

The 2001 Bhuj earthquake, which occurred due to rupturing of a hidden reverse fault, caused large-scale ground deformation. The ground deformations in the Bhuj earthquake-affected region have been analysed using two interferometric synthetic aperture radar (InSAR) data sets. The data sets belong to the years 2003–2004 and 2004–2005, covering an area east of Bhuj falling on near-flat terrain north of Kutch Mainland Fault (KMF). Two interferograms have been generated successfully displaying the interference fringes in the study area, enabling us to draw interesting observational inferences. The 2003–2004 interferogram image exhibits upliftment of about 8 cm (surface motion towards the satellite) around Kunjisar village and also upliftment of 25 and 5 cm in the other two areas north of Kunjisar, whereas the interferogram image belonging to the year 2004–2005 reveals subsidence of about 17 cm (surface motion away from the satellite) in Kunjisar area along with subsidence of about 28 and 5 cm in the two areas north and northwest of Kunjisar, respectively. Hence, between the years 2003 and 2005, two different episodes of upliftment and subsidence have been observed in the study area. The ground upliftment during 2003–2004 probably indicates that the last phase of ground deformation in the earthquake-affected region has been followed by the onset of subsidence during 2004–2005 as the rock volume involved in stress–strain processes began to experience a relaxation phase.     

Faster Algorithms for Stable Allocation Problems

We consider a high-multiplicity generalization of the classical stable matching problem known as the stable allocation problem, introduced by Baïou and Balinski in 2002. By leveraging new structural properties and sophisticated data structures, we show how to solve this problem in O(mlog?n) time on a bipartite instance with n vertices and m edges, improving the best known running time of O(mn). Building on this algorithm, we provide an algorithm for the non-bipartite stable allocation problem running in O(mlog?n) time with high probability. Finally, we give a polynomial-time algorithm for solving the “optimal” variant of the bipartite stable allocation problem, as well as a 2-approximation algorithm for the NP-hard “optimal” variant of the non-bipartite stable allocation problem.     

Membrane Tension–Mediated Growth of Liposomes

Recent years have seen a tremendous interest in the bottom‐up reconstitution of minimal biomolecular systems, with the ultimate aim of creating an autonomous synthetic cell. One of the universal features of living systems is cell growth, where the cell membrane expands through the incorporation of newly synthesized lipid molecules. Here, the gradual tension‐mediated growth of cell‐sized (≈10 µm) giant unilamellar vesicles (GUVs) is demonstrated, to which nanometer‐sized (≈30 nm) small unilamellar vesicles (SUVs) are provided, that act as a lipid source. By putting tension on the GUV membranes through a transmembrane osmotic pressure, SUV–GUV fusion events are promoted and substantial growth of the GUV is caused, even up to doubling its volume. Thus, experimental evidence is provided that membrane tension alone is sufficient to bring about membrane fusion and growth is demonstrated for both pure phospholipid liposomes and for hybrid vesicles with a mixture of phospholipids and fatty acids. The results show that growth of liposomes can be realized in a protein‐free minimal system, which may find useful applications in achieving autonomous synthetic cells that are capable of undergoing a continuous growth–division cycle.     

On Physical Layer Security of Double Shadowed Rician Fading Channels

Wireless Personal Communications - With the proliferation of fifth-generation (5G) mobile communication wireless networks, the investigation into the performance of physical layer secrecy is...     

Ultrafast Photo-Thermal Switching of Terahertz Spin Currents

Dissipationless and scattering-free spin-based terahertz electronics is the futuristic technology for energy-efficient information processing. Femtosecond light pulse provides an ideal pathway for exciting the ferromagnet (FM) out-of-equilibrium, causing ultrafast demagnetization and superdiffusive spin transport at sub-picosecond timescale, giving rise to transient terahertz radiation. Concomitantly, light pulses also deposit thermal energy at short timescales, suggesting the possibility of abrupt change in magnetic anisotropy of the FM that could cause ultrafast photo-thermal switching (PTS) of terahertz spin currents. Here, a single light pulse induced PTS of the terahertz spin current manifested through the phase reversal of the emitted terahertz photons is demonstrated. The switching of the transient spin current is due to the reversal of the magnetization state across the energy barrier of the FM layer. This demonstration opens a new paradigm for on-chip spintronic devices enabling ultralow-power hybrid electronics and photonics fueled by the interplay of charge, spin, thermal, and optical signals.     

Path planning of humanoids based on artificial potential field method in unknown environments

In this paper, an artificial potential field based navigational controller has been developed for motion planning of humanoid robots. Here, NAO robots are used as the humanoid platform using the underlying principles of potential field based method. The movement of the robot is considered to be under a negative gradient scheme by the combined effect of attractive and repulsive forces generated due to target and obstacles, respectively. The working of the controller is tested in a V‐REP simulation platform, and the simulation results are validated through a real‐time experimental set‐up developed under laboratory conditions. Here, the navigation of both single and multiple humanoids has been attempted. For avoiding intercollision among multiple humanoids during their navigation in a common platform, a Petri‐Net control scheme has been proposed. The results obtained from both the simulation and experimental platforms are compared against each other with a good agreement between them having minimal percentage of deviations. Finally, the proposed controller is also evaluated against another existing navigational model, and a significant performance improvement has been observed.     

Dithiobiurets: a novel class of acid corrosion inhibitors for mild steel

The corrosion inhibition behaviour of some substituted dithiobiurets, namely, -1,5-diphenyl-2,4-dithiobiuret (DPDTB), 1-tolyl-5-phenyl-2,4-dithiobiuret (TPDTB), 1-anisidyl-5-phenyl-2,4-dithiobiuret (APDTB), 1-chorophenyl-5-diphenyl-2,4-dithiobiuret (CPDTB) were studied in 1 to 5 M HCl on mild steel. The characteristics of these compounds are explained in terms of factors such as inhibitor concentration, acid concentration, temperature, immersion time and molecular structure. Potentiodynamic polarization and a.c. impedance techniques were used to investigate the inhibition mechanism. Among the compounds studied APDTB exhibited the best performance giving more than 98% inhibition efficiency (IE) in HCl solutions. DPDTB and CPDTB were found to reduce hydrogen permeation through mild steel in HCl solutions. The adsorption of APDTB was also confirmed by Auger electron spectroscopy (AES).     

Synthesis and Characterization of Thermochemical Storage Material Combining Porous Zeolite and Inorganic Salts

Thermal energy storage has the potential to decarbonize the heating sector, facilitating the use of renewable energy sources, in particular solar thermal energy. In this paper we present a study on thermochemical storage material composed of inorganic salts hosted in the porous matrix of zeolite 13X; we prepared a series of composites containing different amounts of inorganic salts – MgCl₂, MgSO₄ by impregnation method and we characterized them by multiple experimental techniques: energy storage and adsorption/desorption rates were assessed using simultaneous thermal analysis by coupling thermogravimetric and differential scanning calorimetry, microstructure, and composition were assessed through scanning electron microscopy and energy-dispersive X-ray spectroscopy. Finally, thermal conductivity was measured by laser flash analysis. With our composite material, we achieved an energy density of 400 kJ/kg across the temperature range 30–150°C and a 35% increase in thermal conductivity by adding 1% of multiwall carbon nanotubes. These features make the material an interesting option for thermal storage in buildings. We attribute the behavior of the material to the combination of large zeolite-specific area coupled with the heat of water sorption/hydration of MgCl₂, MgSO₄.     

Bi-metallic and tri-metallic Pt-Sn/C, Pt-Ir/C, Pt-Ir-Sn/C catalysts for electro-oxidation of ethanol in direct ethanol fuel cell

In the present work, combination of bi-metallic and tri-metallic Pt, Ir, Sn electro-catalysts was prepared by impregnation reduction method on carbon Vulcan XC-72 to improve upon electro-oxidation of ethanol in direct ethanol fuel cell. The prepared electro-catalysts were characterized by means of scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses. XRD and TEM analyses reveal that the prepared catalysts are of nano size (6-10 nm) range. It is shown that Pt lattice parameter decreases with the addition of Ir, and increases with the addition of Sn in Pt-Ir-Sn/C catalyst. The electro-catalytic activities characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA) techniques reveal that the addition of small amount of Ir in Pt-Sn/C electro-catalyst exhibits higher activity towards ethanol oxidation than the Pt-Sn/C (20% Pt and 20% Sn by wt) electro-catalyst. The single direct ethanol fuel cell (DEFC) test at 90 °C, 1 bar with catalyst loading of 1 mg/cm² and 2 M ethanol as anode feed showed an enhancement of catalytic activity in following order: Pt-Ir-Sn/C (20% Pt, 5% Ir and 15% Sn by wt) > Pt-Ir-Sn/C (20% Pt, 10% Ir and 10% Sn by wt) > Pt-Sn/C (20% Pt and 20% Sn by wt) > Pt-Ir-Sn/C (10% Pt, 15% Ir and 15% Sn by wt) > Pt-Ir/C (20% Pt and 20% Ir by wt) >    Pt/C (40% Pt by wt). Pt-Ir-Sn/C (20% Pt, 5% Ir and 15% Sn by wt) exhibited highest performance among all the catalysts prepared with power density of 29 mW/cm² in DEFC operating at 90 °C.