Direct Analysis of Thallium in Solid Samples of Bovine Liver and Tomato Leaves by Laser Excited Atomic Fluorescence Spectrometry Using a Graphite Furnace

Laser excited atomic fluorescence spectrometry (LEAFS) with a N₂-laser pumped dye laser with a Shimadzu GFA-4A graphite furnace is used to determine thallium in solid samples of bovine liver and tomato leaves. The linear range for thallium under the studied conditions is 0–50 pg. The instrumental LEAFS detection limit for thallium was 100 fg. Solid samples from National Institute of Standards and Technology were analyzed by this method. The content of thallium in bovine liver and tomato leaves was 0.059 and 0.055 μg/g with relative standard deviation of 12.5% and 15.8% respectively; the results obtained are within the reported limit.     

An Introduction to the Physics of Particle Accelerators,by Mario Conte and William W. MacKay

Hydrodynamic and Hydromagnetic Stability. By S. Chandrasekhar. (Clarendon Press :Oxford University Press, 1961.) [Pp. xx + 652.] 105s.

Twenty-five Years of B.B.C. Television. By Sir Harold Bishop. [B.B.C. Engineering Division Monographs No. 39.1 (B.B.C., 1961.) [Pp. 41.1 5s.

Boundary and Eigeneralue Problems in Mathematical Physics. By Hans Sagan. Oyiley &; Sons, 1961.) [Pp. xviii + 3811. 76s.

Quantum Mechanics. By E. Merzbacher. (J. Wiley &; Sons, 1961.) [Pp. xii+544.] 96s.

(1) Careers in High School Physics Teaching. (2) Careers in College Physics Teaching. Published by the American Institute of Physics, under a grant from the National Science Foundation, April and May 1962. [Pp. 20 and 24.]     

Phase space analysis of interacting dark energy in f(T) cosmology

In this paper, we examine the interacting dark energy model in f(T) cosmology. We assume dark energy as a perfect fluid and choose a specific cosmologically viable form f(T) = ????T. We show that there is one attractor solution to the dynamical equation of f(T) Friedmann equations. Further we investigate the stability in phase space for a general f(T) model with two interacting fluids. By studying the local stability near the critical points, we show that the critical points lie on the sheet u* = (c ? 1)v* in the phase space, spanned by coordinates (u, v, ??, T). From this critical sheet, we conclude that the coupling between the dark energy and matter c ?? (?2, 0).     

Investigation of electron energy states in InGaN/GaN multiple quantum wells

Blue light emitting diodes (LED) consisting of InGaN/GaN multiple quantum wells (MQWs) have been grown by metal organic chemical vapor deposition (MOCVD) on sapphire. The width of the quantum wells (InGaN) was maintained in the range of 3–5 nm with a barrier of 10–15 nm of GaN. Various diagnostic techniques were employed for the characterization of the InGaN/GaN heterostructure. Carrier concentration depth profile from C–V measurements demonstrated the presence of MQWs. The higher value of built-in voltage (15 V) determined from C⁻²–V plot also supported the presence of MQWs as assumed to alter the space-charge region width and hence the intercept voltage. Arrhenius plots due to DLTS spectra from the device revealed at least four energy states (eV) 0.1, 0.12, 0.15 and 0.17, respectively in the quantum wells, with respect to the barrier. Further the photoluminescence spectrum showed an InGaN-based broad band centered at 2.9 eV and the GaN peak at 3.4 eV. A comparison of the PL spectrum with the literature helped to estimate the indium content in the QW (InGaN) and its width to be ∼13% and ∼3 nm, respectively. The results were consistent with the DLTS findings.     

Power-Law Entropy-Corrected HDE and NADE in Brans-Dicke Cosmology

Considering the power-law corrections to the black hole entropy, which appear in dealing with the entanglement of quantum fields inside and outside the horizon, the holographic energy density is modified accordingly. In this paper we study the power-law entropy-corrected holographic dark energy in the framework of Brans-Dicke theory. We investigate the cosmological implications of this model in detail. We also perform the study for the new agegraphic dark energy model and calculate some relevant cosmological parameters and their evolution. As a result we find that this model can provide the present cosmic acceleration and even the equation of state parameter of this model can cross the phantom line w _D =−1 provided the model parameters are chosen suitably.     

Unsteady flow of viscoelastic fluid between two cylinders using fractional Maxwell model

The unsteady flow of an incompressible fractional Maxwell fluid between two infinite coaxial cylinders is studied by means of integral transforms.The motion of the fluid is due to the inner cylinder that applies a time dependent torsional shear to the fluid.The exact solutions for velocity and shear stress are presented in series form in terms of some generalized functions.They can easily be particularized to give similar solutions for Maxwell and Newtonian fluids.Finally,the influence of pertinent parameters on the fluid motion,as well as a comparison between models,is highlighted by graphical illustrations.     

Study of neutron response for two hybrid RPC setups using the GEANT4 MC simulation approach

The present article describes a detailed neutron simulation study in the energy range 10^-10 MeV to 1.0 GeV for two different RPC configurations. The simulation studies were taken by using the GEANT4 MC code. Aluminum was utilized on the GND and readout strips for the （a） Bakelite-based and （b） glass-based RPCs. For the former type of RPC setup the neutron sensitivity for the isotropic source was Sn = 2.702 × 10^-2 at En = 1.0 GeV, while for the latter type of RPC, the neutron sensitivity for the same source was evaluated as Sn = 4.049 × 10^-2 at En = 1.0 GeV. These results were further compared with the previous RPC configuration in which copper was used for ground and pickup pads. Additionally A1 was employed at （GND＋strips） of the phosphate glass RPC setup and compared with the copper-based phosphate glass RPC. Good agreement with sensitivity values was obtained with the current and previous simulation results.     

The Rayleigh–Stokes problem for an edge in a generalized Oldroyd-B fluid

The velocity field corresponding to the Rayleigh–Stokes problem for an edge, in an incompressible generalized Oldroyd-B fluid has been established by means of the double Fourier sine and Laplace transforms. The fractional calculus approach is used in the constitutive relationship of the fluid model. The obtained solution, written in terms of the generalized G-functions, is presented as a sum of the Newtonian solution and the corresponding non-Newtonian contribution. The solution for generalized Maxwell fluids, as well as those for ordinary Maxwell and Oldroyd-B fluids, performing the same motion, is obtained as a limiting case of the present solution. This solution can be also specialized to give the similar solution for generalized second grade fluids. However, for simplicity, a new and simpler exact solution is established for these fluids. For β → 1, this last solution reduces to a previous solution obtained by a different technique.      

Banana peel: A green and economical sorbent for the selective removal of Cr(VI) from industrial wastewater

This study describes the use of banana peel, a commonly produced fruit waste, for the removal of Cr(VI) from industrial wastewater. The parameters pH, contact time, initial metal ion concentration, and temperature were investigated and the conditions resulting in rapid and efficient adsorption (95% within 10 min) were determined. The binding of metal ions was found to be pH dependent with the optimal sorption occurring at pH 2. The retained species were eluted with 5 mL of 2 M H₂SO₄. To elucidate the mechanism of the process, total amounts of chromium and Cr(VI) were analyzed using flame atomic absorption and ultraviolet–visible (UV–vis) spectroscopic techniques, respectively. The Langmuir and Dubinin–Radushkevich (D–R) isotherms were used to describe the partitioning behavior for the system at different temperatures. Kinetics and thermodynamics of Cr(VI) removal by banana peel were also studied. The influence of diverse ions on the sorption behavior revealed that only Fe(II) ions (of those tested) suppressed the sorption of Cr(VI) ions to some extent. The method was applied for the removal of Cr(VI) from industrial wastewater.