Rapid vertical mixing rates in deep waters of the Andaman Basin

The Andaman Basin is an enclosed region in the northeastern Indian Ocean with its deep water below approximately 1800 m almost isolated with respect to horizontal ventilation by the Andaman-Nicobar Islands separating it from the Bay of Bengal. The physical and chemical properties including radiocarbon ((14)C) measured at two stations of the Andaman Basin show negligible variation with depth in the waters below 1300 m, indicating a well-mixed water mass. This study attempts to derive the mixing rates for deep waters of the Andaman Basin. Model calculations based on (14)C profile measurements indicate rapid vertical mixing (vertical advection velocity, w>200 m year(-1)) in waters deeper than 1800 m of the basin. For a basin with deep water thickness of 1000 m below 1800 m, deduced mixing rate of >200 m year(-1) translates to mixing time of <5 years. As shown for other regions, the possible mechanism responsible for such high vertical mixing rates could be the internal waves generated from tidal currents flowing through rough topography. In addition, Andaman Basin is underlain with a young crust and is known for its high heat flow, which also could contribute to the high vertical mixing.     

Characterization of (Th,U)O2 pellets made by advanced CAP process

Coated Agglomerate Pelletization (CAP) process is being developed by Bhabha Atomic Research Centre (BARC) for the fabrication of ThO₂-UO₂ mixed oxide fuel pellets. In order to improve the microstructures with better microhomogeneity, a study was made to modify the CAP process. The advanced CAP (A-CAP) process is similar to the CAP process except that the co-precipitated powder of mixed oxide, ThO₂-30%UO₂ or ThO₂-50%UO₂, is used for coating instead of U₃O₈ powder. The choice of ThO₂-UO₂ powders as the coating material is advantageous compared to U₃O₈, since the presence of large quantities of ThO₂ in UO₂ powder gives better self-shielding effect. In this paper, ThO₂ containing 4%UO₂ (% in weight) was prepared by the A-CAP process. Property measurements including microstructure and microhomogeneity were made by optical microscopy, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), etc. It was found that the pellets sintered in air at 1400 °C showed a duplex grain structure and those sintered in Ar-8%H₂ at 1650 °C showed a very uniform grain structure with excellent microhomogeneity.     

Condensation on a spray of water drops: a cell model study-II. Transport quantities

The formulation for a unit cylinder cell model that was used to analyze the hydrodynamics and heat transfer associated with steam condensation on a spray of equal sized water droplets was presented in part I of this study. In this part II, we report the results and discussions for the condensation induced interfacial velocities, surface shear stress, Nusselt number and the Sherwood number. The heat transport in both phases and the species transport in the continuous phase have been treated as transient processes. The interactions between neighboring drops have been examined. Numerically obtained transport results have been compared with an experimental study. Results for a representative spray show that the use of correlations developed for an isolated drop to predict condensation spray behavior may be inaccurate, although isolated drop studies continue to merit investigations.     

Generic Molding Platform for Simple,Low‐Cost Fabrication of Polymeric Microneedles

Micromolding technology is widely used for the fabrication of polymer microneedles for transdermal and intradermal drug delivery applications. Geometric features of microneedles in molding are solely determined by geometry of the master mold template. Fabrication of master mold template usually involves costly and cumbersome technologies due to small feature sizes typical of microneedles. In this research, a novel molding platform is designed that is fabricated using low‐cost and simple techniques with flexibility of producing large number of microneedle geometries. The proposed molding platform eliminates need for developing multiple mold templates for fabrication of various geometries of polymer microneedles. Utility of this molding platform is demonstrated in polylactic acid‐based solid thermoplastic microneedles and polyacrylic acid‐based dissolvable microneedles with various aspect ratio settings. Various microneedles fabricated at heights differing with resolution of as low as 100 µm are successfully achieved using specified settings in the molding platform. The suitability of fabricated microneedles for drug delivery applications is evaluated by in vitro and in vivo testing.     

Zur Berechnung kontinuierlicher Fettspaltanlagen

Calculation of Continuous Fat-Splitting Plant Continuous counter current fat-splitting can be considered as a counter current extraction on which slow proceeding chemical reaction is superimposed. A graphical method of calculation commonly used for the counter current extraction is modified for the mixture of 4 substances present in case of fat-splitting. By this means the mass and concentration proportions in the continuous fat-splitting can be clearly represented and furthermore interesting conclusions can be drawn.     

Memory-based approaches for eliminating premature convergence in particle swarm optimization

Applied Intelligence - Particle Swarm Optimization (PSO) is a computational method in which a group of particles moves in search space in search of an optimal solution. During this movement, each...     

Amorphous SnO–Sb2O3–SiO2 glassy anode: high-performance electrode materials for Na-ion batteries

Journal of Materials Science: Materials in Electronics - Amorphous SnO–Sb2O3–SiO2 glass anode prepared by simple mechanical ball milling method. Physical and electrochemical properties...     

Characterization of ThO2-UO2 pellets made by co-precipitation process

The co-precipitation technique renders an excellent route to obtain a homogeneous mixture of ThO₂ and UO₂ powders. In this process, after the nitrate solutions of Th and U are mixed in the intended ratio, oxalic acid is added for co-precipitation. The precipitate is then dried and calcined to get a solid solution of ThO₂ and UO₂. In this study, ThO₂-30%UO₂ and ThO₂-50%UO₂ (% in weight) powders were characterized in terms of particle size, particle shape, surface area, phase content, O/M ratio etc. The pellets obtained by sintering these powders were characterized with the help of optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The XRD data for ThO₂-30%UO₂ and ThO₂-50%UO₂ pellets showed the presence of a small amount of U₃O₈ phase besides fluorite phase. The grain size of ThO₂-30%UO₂ and ThO₂-50%UO₂ was found to be 5.7 and 4.5 μm, respectively.     

10Be annual fallout in rains in India

The ¹⁰Be concentrations of annual rainfall collections during 1979–1981, at eight stations in India, ranged from 0.43 × 10⁷ to 8.48 × 10⁷ atoms/l and the corresponding ¹⁰Be fallouts are in the range of 0.31 × 10 ⁶ to 2.73 × 10⁶ atoms cm^?2 a^?1. The estimated ¹⁰Be global fallout based on the presently available data is 1.55 × 10⁷ atoms^?2 a^?1 or 5 × 10^?2 atoms cm^?2 s^?1. Most of the measured rates of fallout and deep sea deposition of ¹⁰Be are a factor of 2–3 lower than the present estimate.