Solution of a problem of flow in a porous medium with limiting gradient

For the law of flow in a porous medium with limiting gradient studied previously in [1], an exact solution is found for the problem formulated in [2] of the plane steady motion of an incompressible fluid in a channel with a rectangular step. Particular cases of the solution obtained are given; these represent the solutions of the problem of flow past a broken wall and of motion from a point source in a strip.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 76–78, January–February, 1985.     

Accelerator development in India for ADS programme

At BARC, development of a Low Energy High Intensity Proton Accelerator (LEHIPA), as front-end injector of the 1 GeV accelerator for the ADS programme, has been initiated. The major components of LEHIPA (20 MeV, 30 mA) are a 50 keV ECR ion source, a 3 MeV Radio Frequency Quadrupole (RFQ) and a 20 meV drift tube linac (DTL). The Low Energy Beam Transport (LEBT) and Medium Energy Beam Transport (MEBT) lines match the beam from the ion source to RFQ and from RFQ to DTL respectively. Design of these systems has been completed and fabrication of their prototypes has started. Physics studies of the 20–1000 MeV part of the Linac are also in progress. In this paper, the present status of this project is presented.      

Polarization encoded all-optical quaternary R-S flip-flop using binary latch

The developments of different multi-valued logic (MVL) systems have received considerable interests in recent years all over the world. In electronics, efforts have already been made to incorporate multi-valued system in logic and arithmetic data processing. But, very little efforts have been given in realization of MVL with optics. In this paper we present novel designs of certain all-optical circuits that can be used for realizing multi-valued logic functions. Polarization encoded all-optical quaternary (4-valued) R-S flip-flop is proposed and described. Two key circuits (all-optical encoder/decoder and a binary latch) are designed first. They are used to realize quaternary flip-flop in all-optical domain. Here the different quaternary logical states are represented by different polarized state of light. Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch can take an important role. Computer simulation result confirming described methods and conclusion are given in this paper.     

Discovery and evaluation of inhibitory activity and mechanism of arylcoumarin derivatives on Theileria annulata enolase by in vitro and molecular docking studies

Molecular Diversity - In this study, the inhibition potential of 3- and 4-arylcoumarin derivatives on Theileria annulata enolase (TaENO) was assessed for the first time in the literature. Firstly,...     

Photophysical Study of Local Anesthetics in Reverse Micelles and Water-Ethanol Mixtures

Fluorescence emission from three tertiary amine local anesthetics, dibucaine (D), tetracaine (T), and procaine (P) was investigated in the membrane-mimetic environment of AOT/isooctane reverse micelles and water-ethanol mixtures. At room temperature all three show broad UV absorption bands and large Stokes' shifts in emission from aqueous medium. In reverse micelles the emission bands are blue-shifted, with the magnitude of this shift decreasing continuously as the waterto-surfactant molar ratio (w₀) of the micelles is increased. The emission intensity of D is much stronger in water and in the interior of micelles than in ethanol, whereas for T and P the emission in water is much weaker than in ethanol and in micelles. Whereas the behavior in micelles is the result of the increased hydrophobicity with respect to bulk water in their interior, that in waterethanol mixtures may be explained on the basis of state reversal of the excited electronic levels of D with increasing hydrogen bonding capability of the solvent mixture. The steady-state anisotropy for both T and P is unusually high in bulk water (0.27) and increases with increasing w₀ in micelles. However, the rotational correlation time of the anesthetics, as calculated using Perrin's equation, decreases with increasing w₀, as expected from physical considerations relating the size of the water pool to the ease of rotational relaxation of probe molecules inside micelles. Together, these results point to a marked difference in emission properties between D on one hand and T and P on the other, arising from differences in electronic characters of their primary emitting chromophores—quinoline for D, para amino benzoate for T and P.     

Electron impact single ionization of mono- and di-positive ions

The electron impact ionization cross-sections of mono- and di-positive ionic targets are calculated using a second version of the modified binary-encounter-dipole (MBED) model, previously reported [M A Uddinet al, J. Phys. B37, 1909 (2004)]. The present version differs from the previous one in the scale factor of the Burgess denominator and is applicable to targets with chargesq = 1 and 2. The MBED in the present form is found to work well for 11 ionic targets ranging from Be⁺ to K⁺ and complements its previous version valid for targets withq s> 2     

A functional central limit theorem for a class of urn models

We construct an independent increments Gaussian process associated to a class of multicolor urn models. The construction uses random variables from the urn model which are different from the random variables for which central limit theorems are available in the two color case.     

Species dependent extraction of 99Mo

The liquid–liquid extraction profile of molybdenum has been studied with di-(2-ethylhexyl) phosphoric acid from different HCl media. The careful study of extraction profile clearly indicates various species of molybdenum at different acid strengths, which have been interpreted with reference to established data.     

Total Synthesis of Norditerpene Alcohols

The plant Thuja Plicate Donn which is known under the name of western red cedar has been concern to chemical study owing to its medical and industrial importance.¹ Extensive chemical investigations aiming to identify its constituents resulted the isolation of terpenes, essential oils, antibiotics and antifungal compounds.² Few years ago the Canadian chemists isolated two norditerpene alcohols 1 and 2 from the bark of western cedar.³ The present communication documents our approach to the synthesis of alcohols 1 and 2.     

Instability and dewetting of ultrathin solid viscoelastic films on homogeneous and heterogeneous substrates

Instability and dewetting engendered by the van der Waals force in soft thin (<100 nm) linear viscoelastic solid (e.g., elastomeric gel) films on uniform and patterned surfaces are explored. Linear stability analysis shows that, although the elasticity of the film controls the onset of instability and the corresponding critical wavelength, the dominant length-scale remains invariant with the elastic modulus of the film. The unstable modes are found to be long-wave, for which a nonlinear long-wave analysis and simulations are performed to uncover the dynamics and morphology of dewetting. The stored elastic energy slows down the temporal growth of instability significantly. The simulations also show that a thermodynamically stable film with zero-frequency elasticity can be made unstable in the presence of physico-chemical defects on the substrate and can follow an entirely different pathway with far fewer holes as compared to the viscous films. Further, the elastic restoring force can retard the growth of a depression adjacent to the hole-rim and thus suppress the formation of satellite holes bordering the primary holes. These findings are in contrast to the dewetting of viscoelastic liquid films where nonzero frequency elasticity accelerates the film rupture and promotes the secondary instabilities. Thus, the zero-frequency elasticity can play a major role in imposing a better-defined long-range order to the dewetted structures by arresting the secondary instabilities.