A little more gauge mediation and the light Higgs mass

We consider minimal models of gauge mediated supersymmetry breaking with an extra U(1) factor in addition to the Standard Model gauge group. A U(1) charged, Standard Model singlet is assumed to be present which allows for an additional NMSSM like coupling, lambda HuHdS. The U(1) is assumed to be flavour universal. Anomaly cancellation in the MSSM sector requires additional coloured degrees of freedom. The S field can get a large vacuum expectation value along with consistent electroweak symmetry breaking. It is shown that the lightest CP even Higgs boson can attain mass of the order of 125 GeV. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).

Feshbach resonance in a synthetic non-Abelian gauge field

We study the Feshbach resonance of spin-1/2 particles in a uniform synthetic non-Abelian gauge field that produces spin-orbit coupling and constant spin potentials. We develop a renormalizable quantum field theory including the closed-channel boson which engenders the resonance. We show that the gauge field shifts the Feshbach field where the low-energy scattering length diverges. In addition the Feshbach field is shown to depend on the center-of-mass momentum of the particles. For high-symmetry gauge fields which produce a Rashba spin coupling, we show that the system supports two bound states over a regime of magnetic fields when the background scattering length is negative and the resonance width is comparable to the energy scale of the spin-orbit coupling. We discuss interesting consequences useful for future theoretical and experimental studies, even while our predictions are in agreement with recent experiments.

Iodide Retention by Modified Kaolinite in the Context of Safe Disposal of High Level Nuclear Waste

Bentonite clay is identified as potential buffer in deep geological repositories (DGR) that store high level radioactive wastes (HLW) as the expansive clay satisfies the expected mechanical and physicochemical functions of the buffer material. In the deep geological disposal of HLW, iodine-129 is one of the significant nuclides, attributable to its long half-life (half life 1⁄4 1:7 × 107 years). However, the negative charge on the basal surface of bentonite particles precludes retention of iodide anions. To render the bentonite effective in retaining hazardous iodide species in DGR, improvement of the anion retention capacity of bentonite becomes imperative. The iodide retention capac-ity of bentonite is improved by admixing 10 and 20% Ag-kaolinite (Ag-K) with bentonite (B) on a dry mass basis. The present study produced Ag-kaolinite by heating silver nitrate-kaolinite mixes at 400°C. Marginal release of iodide retained by Ag-kaolinite occurred under extreme acidic (pH 1⁄4 2:5) and alkaline (pH 1⁄4 12:5) conditions. The swell pressure and iodide etention results of the B-Ag-K specimens bring out that mixing Ag-K with bentonite does not chemically modify the expansive clay; the mixing is physical in nature and Ag-K presence only contributes to iodide retention of the admixture. DOI: 10.1061/(ASCE)HZ.2153-5515.0000121. © 2012 American Society of Civil Engineers.

Effect of angle of incidence on mixed convective wake dynamics and heat transfer past a square cylinder in cross flow at Re=100

In this paper, a numerical investigation is performed to study the mixed convective flow and heat transfer characteristics past a square cylinder in cross flow at incidence. Utilizing air (Pr = 0.71) as an operating fluid, computations are carried out at a representative Reynolds number (Re) of 100. Angles of incidences are varied as, 0 degrees <= alpha <= 45 degrees. Effect of superimposed positive and negative cross-flow buoyancy is brought about by varying the Richardson number (RI) in the range -1.0 <= Ri <= 1.0. The detail features of flow topology and heat transport are analyzed critically for different angles of incidences. The thermo fluidic forces acting on the cylinder during mixed convection are captured in terms of the drag (C-D), lift (C-L), and moment (C-M) coefficients. The results show that the lateral width of the cylinder wake reduces with increasing alpha and the isotherms spread out far wide. In the range 0 degrees < alpha < 45 degrees, C-D reduces with increasing Ri. The functional dependence of C-M with Ri reveals a linear relationship. Thermal boundary layer thickness reduces with increasing angle of incidences. The global rate of heat transfer from the cylinder increases with increasing alpha. (C) 2014 Elsevier Ltd. All rights reserved.

Modeling of Bubble-Size Distribution in Water and Freon Co-Blown Free Rise Polyurethane Foams

A model has been developed to simulate the foam characteristics obtained, when chemical (water) and physical (Freon) blowing agents are used together for the formation of polyurethane foams. The model considers the rate of reaction, the consequent rise in temperature of the reaction mixture, nucleation of bubbles, and mass transfer of CO2 and Freon to them till the time of gelation. The model is able to explain the experimental results available in literature. It further predicts that the nucleation period gets reduced with increase in water (at constant Freon content), whereas with increase in Freon (at constant water) concentration nucleation period decreases marginally leading to narrower bubble-size distribution. By the use of uniform sized nuclei added initially, the model predicts that the bubble-size distribution can be made independent of the rate of homogeneous nucleation and can, thus, offer an extra parameter for its control. (C) 2014 Wiley Periodicals, Inc.

Germanane: a Low Effective Mass and High Bandgap 2-D Channel Material for Future FETs

We investigate the electronic properties of Germanane and analyze its importance as 2-D channel material in switching devices. Considering two types of morphologies, namely, chair and boat, we study the real band structure, the effective mass variation, and the complex band structure of unstrained Germanane by density-functional theory. The chair morphology turns out to be a more effective channel material for switching devices than the boat morphology. Furthermore, we study the effect of elastic strain, van der Waals force, and vertical electric field on these band structure properties. Due to its very low effective mass with relatively high-energy bandgap, in comparison with the other 2-D materials, Germanane appears to provide superior performance in switching device applications.

Maximum mass of stable magnetized highly super-Chandrasekhar white dwarfs: stable solutions with varying magnetic fields

We address the issue of stability of recently proposed significantly super-Chandrasekhar white dwarfs. We present stable solutions of magnetostatic equilibrium models for super-Chandrasekhar white dwarfs pertaining to various magnetic field profiles. This has been obtained by self-consistently including the effects of the magnetic pressure gradient and total magnetic density in a general relativistic framework. We estimate that the maximum stable mass of magnetized white dwarfs could be more than 3 solar mass. This is very useful to explain peculiar, overluminous type Ia supernovae which do not conform to the traditional Chandrasekhar mass-limit.

Studying electrons on curved surfaces by trapping and manipulating multielectron bubbles in liquid helium

Investigations of two-dimensional electron systems (2DES) have been achieved with two model experimental systems, covering two distinct, non-overlapping regimes of the 2DES phase diagram, namely the quantum liquid phase in semiconducting heterostructures and the classical phases observed in electrons confined above the surface of liquid helium. Multielectron bubbles in liquid helium offer an exciting possibility to bridge this gap in the phase diagram, as well as to study the properties of electrons on curved flexible surfaces. However, this approach has been limited because all experimental studies have so far been transient in nature. Here we demonstrate that it is possible to trap and manipulate multielectron bubbles in a conventional Paul trap for several hundreds of milliseconds, enabling reliable measurements of their physical properties and thereby gaining valuable insight to various aspects of curved 2DES that were previously unexplored.

Anatomy of Higgs mass in supersymmetric inverse seesaw models

We compute the one loop corrections to the CP-even Higgs mass matrix in the supersymmetric inverse seesaw model to single out the different cases where the radiative corrections from the neutrino sector could become important. It is found that there could be a significant enhancement in the Higgs mass even for Dirac neutrino masses of O(30) GeV if the left-handed sneutrino soft mass is comparable or larger than the right-handed neutrino mass. In the case where right-handed neutrino masses are significantly larger than the supersymmetry breaking scale, the corrections can utmost account to an upward shift of 3 GeV. For very heavy multi TeV sneutrinos, the corrections replicate the stop corrections at 1-loop. We further show that general gauge mediation with inverse seesaw model naturally accommodates a 125 GeV Higgs with TeV scale stops. (C) 2014 The Authors. Published by Elsevier B.V.

Contrasting geochemical signatures on land from the Middle and Late Permian extinction events

The end of the Palaeozoic is marked by two mass-extinction events during the Middle Permian (Capitanian) and the Late Permian (Changhsingian). Given similarities between the two events in geochemical signatures, such as large magnitude negative C-13 anomalies, sedimentological signatures such as claystone breccias, and the approximate contemporaneous emplacement of large igneous provinces, many authors have sought a common causal mechanism. Here, a new high-resolution continental record of the Capitanian event from Portal Mountain, Antarctica, is compared with previously published Changhsingian records of geochemical signatures of weathering intensity and palaeoclimatic change. Geochemical means of discriminating sedimentary provenance (Ti/Al, U/Th and La/Ce ratios) all indicate a common provenance for the Portal Mountain sediments and associated palaeosols, so changes spanning the Capitanian extinction represent changes in weathering intensity rather than sediment source. Proxies for weathering intensity chemical index of alteration, W and rare earth element accumulation all decline across the Capitanian extinction event at Portal Mountain, which is in contrast to the increased weathering recorded globally at the Late Permian extinction. Furthermore, palaeoclimatic proxies are consistent with unchanging or cooler climatic conditions throughout the Capitanian event, which contrasts with Changhsingian records that all indicate a significant syn-extinction and post-extinction series of greenhouse warming events. Although both the Capitanian and Changhsingian event records indicate significant redox shifts, palaeosol geochemistry of the Changhsingian event indicates more reducing conditions, whereas the new Capitanian record of reduced trace metal abundances (Cr, Cu, Ni and Ce) indicates more oxidizing conditions. Taken together, the differences in weathering intensity, redox and the lack of evidence for significant climatic change in the new record suggest that the Capitanian mass extinction was not triggered by dyke injection of coal-beds, as in the Changhsingian extinction, and may instead have been triggered directly by the Emeishan large igneous province or by the interaction of Emeishan basalts with platform carbonates.

Biodegradation of acrylamide by acrylamidase from Stenotrophomonas acidaminiphila MSU12 and analysis of degradation products by MALDI-TOF and HPLC

The present study examines an improved detoxification and rapid biological degradation of toxic pollutant acrylamide using a bacterium. The acrylamide degrading bacterium was isolated from the soil followed by its screening to know the acrylamide degrading capability. The minimal medium containing acrylamide (30 mM) served as a sole source of carbon and nitrogen for their active growth. The optimization of three different factors was analyzed by using Response Surface Methodology (RSM). The bacteria actively degraded the acrylamide at a temperature of 32 degrees C, with a maximum growth at 30 mM substrate (acrylamide) concentration at a pH of 7.2. The acrylamidase activity and degradation of acrylamide was determined by High Performance Liquid Chromatography (HPLC) and Matrix Assisted Laser Desorption and Ionization Time of Flight mass spectrometer (MALDI-TOF). Based on 168 rRNA analysis the selected strain was identified as Gram negative bacilli Stenotrophomonas acidaminiphila MSU12. The acrylamidase was isolated from bacterial extract and was purified by HPLC, whose mass spectrum showed a molecular mass of 38 kDa. (C) 2014 Elsevier Ltd. All rights reserved.

Symmetric supercapacitor based on partially exfoliated and reduced graphite oxide in neutral aqueous electrolyte

The partially exfoliated and reduced graphite oxide (PE-RGO) is prepared by low temperature thermal exfoliation of graphite oxide under air atmosphere. A symmetric carbon/carbon supercapacitor is studied in a Na2SO4 aqueous electrolyte. The discharge capacitance is 92 F g(-1), when symmetric cell is cycled between the potential ranges from 0 to 1.6 V. This system demonstrates a stable charge/discharge cycle behavior up to 3000 cycles when the cell is operated at a voltage window of 1.6 V. The utilization ratio of potential window is 90% for this system is attributed to the more negative value of electrodes potential when the cell voltage is set to 0 V. The low-temperature exfoliation approach is convenient for mass production of graphenes at low cost and it can be used as electrode material for energy storage applications. (C) 2014 Elsevier Ltd. All rights reserved.

A non-resonant mass sensor to eliminate the ``missing mass'' effect during mass measurement of biological materials

Resonant sensors and crystal oscillators for mass detection need to be excited at very high natural frequencies (MHz). Use of such systems to measure mass of biological materials affects the accuracy of mass measurement due to their viscous and/or viscoelastic properties. The measurement limitation of such sensor system is the difficulty in accounting for the ``missing mass'' of the biological specimen in question. A sensor system has been developed in this work, to be operated in the stiffness controlled region at very low frequencies as compared to its fundamental natural frequency. The resulting reduction in the sensitivity due to non-resonant mode of operation of this sensor is compensated by the high resolution of the sensor. The mass of different aged drosophila melanogaster (fruit fly) is measured. The difference in its mass measurement during resonant mode of operation is also presented. That, viscosity effects do not affect the working of this non-resonant mass sensor is clearly established by direct comparison. (C) 2014 AIP Publishing LLC.

Reply to ``Comment on `Strongly magnetized cold degenerate electron gas: Mass-radius relation of the magnetized white dwarf'''

We show that the upper bound for the central magnetic field of a super-Chandrasekhar white dwarf calculated by Nityananda and Konar Phys. Rev. D 89, 103017 (2014)] and in the concerned comment, by the same authors, against our work U. Das and B. Mukhopadhyay, Phys. Rev. D 86, 042001 (2012)] is erroneous. This in turn strengthens the argument in favor of the stability of the recently proposed magnetized super-Chandrasekhar white dwarfs. We also point out several other numerical errors in their work. Overall we conclude that the arguments put forth by Nityananda and Konar are misleading.

Metal-organic chemical vapor-deposited cobalt oxide films as negative electrodes for thin film Li-ion battery

In this study, thin films of cobalt oxide (Co3O4) have been grown by the metal-organic chemical vapor deposition (MOCVD) technique on stainless steel substrate at two preferred temperatures (450 degrees C and 500 degrees C), using cobalt acetylacetonate dihydrate as precursor. Spherical as well as columnar microstructures of Co3O4 have been observed under controlled growth conditions. Further investigations reveal these films are phase-pure, well crystallized and carbon-free. High-resolution TEM analysis confirms that each columnar structure is a continuous stack of minute crystals. Comparative study between these Co3O4 films grown at 450 degrees C and 500 degrees C has been carried out for their application as negative electrodes in Li-ion batteries. Our method of electrode fabrication leads to a coating of active material directly on current collector without any use of external additives. A high specific capacity of 1168 micro Ah cm(-2) mu m(-1) has been measured reproducibly for the film deposited at 500 degrees C with columnar morphology. Further, high rate capability is observed when cycled at different current densities. The Co3O4 electrode with columnar structure has a specific capacity 38% higher than the electrode with spherical microstructure (grown at 450 degrees C). Impedance measurements on the Co3O4 electrode grown at 500 degrees C also carried out to study the kinetics of the electrode process. (C) 2014 Published by Elsevier B.V.