Direct dissolution of intact UO<Subscript>2</Subscript> pellet and in situ extraction by organic solutions of TBP-HNO<Subscript>3</Subscript> at atmospheric pressure: role of solvate composition

Recently authors demonstrated direct dissolution of g-level PHWR UO₂ fuel pellet fragments and in situ extraction by TBP-HNO₃ and TiAP-HNO₃ solutions at atmospheric pressures. Extending the work, similar studies were performed on intact unirradiated PHWR UO₂ fuel pellets (~15 g U) with varying compositions of organic solvate of tri-n-butyl phosphate (TBP). It was observed that extent of dissolution was a strong function of organic solution composition TBP·(HNO₃) _x (H₂O) _y . Complete dissolution of intact UO₂ pellet in a reasonable time was observed only in case of a particular solvate composition.     

QM/MM study of the structure, energy storage, and origin of the bathochromic shift in vertebrate and invertebrate bathorhodopsins

By comparing the results from a hybrid quantum mechanics/molecular mechanics method (SORCI+Q//B3LYP/6-31G*:Amber) between vertebrate (bovine) and invertebrate (squid) visual pigments, the mechanism of molecular rearrangements, energy storage, and origin of the bathochromic shift accompanying the transformation of rhodopsin to bathorhodopsin have been evaluated. The analysis reveals that, in the presence of an unrelaxed binding site, bathorhodopsin was found to carry almost 27 kcal/mol energy in both visual pigments and absorb (λ(max)) at 528 nm in bovine and 554 nm in squid. However, when the residues within 4.0 ? radius of the retinal are relaxed during the isomerization event, almost ～16 kcal/mol energy is lost in squid compared to only ～8 kcal/mol in bovine. Loss of a larger amount of energy in squid is attributed to the presence of a flexible binding site compared to a rigid binding site in bovine. Structure of the squid bathorhodopsin is characterized by formation of a direct H-bond between the Schiff base and Asn87.     

Regimes of spray formation in gas-centered swirl coaxial atomizers

Spray formation in ambient atmosphere from gas-centered swirl coaxial atomizers is described by carrying out experiments in a spray test facility. The atomizer discharges a circular air jet and an axisymmetric swirling water sheet from its coaxially arranged inner and outer orifices. A high-speed digital imaging system along with a backlight illumination arrangement is employed to record the details of liquid sheet breakup and spray development. Spray regimes exhibiting different sheet breakup mechanisms are identified and their characteristic features presented. The identified spray regimes are wave-assisted sheet breakup, perforated sheet breakup, segmented sheet breakup, and pulsation spray regime. In the regime of wave-assisted sheet breakup, the sheet breakup shows features similar to the breakup of two-dimensional planar air-blasted liquid sheets. At high air-to-liquid momentum ratios, the interaction process between the axisymmetric swirling liquid sheet and the circular air jet develops spray processes which are more specific to the atomizer studied here. The spray exhibits a periodic ejection of liquid masses whose features are dominantly controlled by the central air jet.     

Nonuniform Sampling and Recovery of?Multidimensional Bandlimited Functions by?Gaussian Radial-Basis Functions

Let S⊂ℝ ^d be a bounded subset with positive Lebesgue measure. The Paley-Wiener space associated to S, PW _S , is defined to be the set of all square-integrable functions on ℝ ^d whose Fourier transforms vanish outside S. A sequence (x _j :j∈ℕ) in ℝ ^d is said to be a Riesz-basis sequence for L ₂(S) (equivalently, a complete interpolating sequence for PW _S ) if the sequence (e^-iáx_j,·?:j ? \mathbb N)(e^{-i\langle x_{j},\cdot \rangle }:j\in \mathbb {N}) of exponential functions forms a Riesz basis for L ₂(S). Let (x _j :j∈ℕ) be a Riesz-basis sequence for L ₂(S). Given λ>0 and f∈PW _S , there is a unique sequence (a _j ) in ℓ ₂ such that the function

Laser drilling of thick material using femtosecond pulse with a focus of dual-frequency beam

Laser drilling is one of the basic, most frequently performed, material removal processes. The drilling aspect ratio is theoretically limited by the size and the focal depth of the machining laser spot. The aspect ratio can be improved by using dual focus. In this paper we describe a focus of two different frequencies based on the longitudinal chromatic aberration arisen when polychromatic collimated light is incident on a positive lens element. In the experiments, a Ti:Sapphire laser of 800 nm wavelength and 150 fs pulse duration was used as a source. Two tightly focused laser spots few hundred micrometers apart from each other were formed by focusing a combined collimated laser beam which contains the fundamental optic frequency and the second harmonic optic frequency. The focus of dual-frequency beam was used to drill a 3 mm thick PMMA plate. The drilling aspect ratio of a dual-frequency beam was compared to that of a focus of single frequency beam. Experimental results reveal that dual-frequency beam increases the aspect ratio and improves the drilling quality in terms of profile of the produced features.     

Theorems of the Alternative over Indefinite Inner Product Spaces

In this paper, we study the Farkas alternative over indefinite inner product spaces using the recently proposed indefinite matrix product.