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The influence of pre-injection of a gas phase on gas–liquid two-phase flow through a vertical minichannel is experimentally investigated. Circular minichannel of 2 mm inner diameter is considered for the investigations. Air is used as a gas phase and water is used as a liquid phase. The superficial gas and liquid velocities are kept as 0.0531–0.2653 and 0.1062–0.2653 m/s, respectively. Inlet premixing of gas–liquid two-phase flow is achieved with an injector equipped with a nozzle to inject a gas phase. Three nozzles are developed with inner diameters of 0.7, 2, 2.5 mm. Direct injection and co-flow pre-injections of gas phase are obtained with various positions of a nozzle (0, 25 and 50 mm) in an injector. Flow patterns such as bubbly flow, Taylor bubble flow and slug-annular flow are observed and captured using an EXILIM high-speed camera. The influence of nozzle size and its positions in an injector on the hydrodynamics of Taylor bubble flow as well as two-phase pressure drop are analysed in detail. Inlet premixing and two-phase flow hydrodynamics have significant influence of gas-phase pre-injection in a vertical minichannel. [ABSTRACT FROM AUTHOR]

Roaster off-gas systems play an important role in reducing SO2emissions to the atmosphere and in ensuring the satisfactory operation of nickel smelters in accordance with environmental regulations. In this paper, the dynamic models for an industrial roaster off-gas system are developed using mass continuity, momentum, and energy conservation laws. Industrial measured pressure data are compared with the steady-state pressure models that are the special case of the developed dynamic models, and good agreement is obtained. On the basis of the developed dynamic models, the effects of important variables on the dynamics of the off-gas system are studied via simulations. The developed dynamic models provide a necessary basis for high performance control development for roaster off-gas systems. [ABSTRACT FROM AUTHOR]

Abstract??Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) metal complexes with Schiff bases derived from 3-formyl-4-hydroxycoumarin and semicarbazone are synthesized and characterized on the basis of elemental analysis, molar conductance, magnetic moment, IR, electronic,1H NMR spectrum, and ESR spectrum,TGA, and X-ray diffraction powder methods. Molar conductance values indicate that the complexes are nonelectrolytic in nature. Magnetic moment and spectral studies suggest either tetrahedral or square-planar geometry around the central metal ions. The analytical data indicate that metal-to-ligand stoichiometry in all complexes is 1: 1. [ABSTRACT FROM AUTHOR]

El artículo examina la necesidad de examinar el problema de la explotación y los abusos sexuales. Según un informe de la organización Save the Children Reino Unido, existe una pauta de explotación sexual de menores refugiados por parte de los trabajadores humanitarios. El artículo explora las iniciativas por la Organización de las Naciones Unidas (ONU) para la asistencia de estas víctimas de explotación.

Abstract  Surface-capped CdSe and CdTe nano-crystals (NCs) have been synthesized using cadmium acetate, oleic acid and respective tri-octylphosphine chalcogenide (TOPE; E = Se/Te) in diphenyl ether (DPE). Well-dispersed CdSe particles showed two absorption bands at the region of 431–34 and 458–60 nm in optical absorption study. A band-edge emission resulted at 515 nm with an excitation energy of 400 nm, in its photoluminescence (PL) spectrum. Similarly, UV–visible absorption study of CdTe revealed an absorption band at [ABSTRACT FROM AUTHOR]