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Peristaltic transport of water-based silver nanoparticles in a symmetric channel with convective walls is explored. Analysis has been carried out in the presence of heat source-sink, viscous dissipation, and mixed convection. Lubrication approach has been utilized. Resulting coupled system is solved numerically using the shooting method. Graphical analysis for flow quantities and heat transfer has been made. Results show that the addition of silver nanoparticles considerably reduces the velocity and temperature of the fluid. Enhancement in heat transfer rate at the wall for large nanoparticle volume fraction is also reported. Interesting outcomes of this study are summarized. PACS Nos.: 47.85.Dh, 47.50.-d, 44.30.+v, 47.55.pb. Nous etudions le transport peristaltique de nanoparticules d'argent dans une base d'eau, circulant dans un canal a parois convectives. L'analyse se fait en presence de sources-puits thermiques, de dissipation visqueuse et de convection mixte. Nous utilisation l'approximation de lubrification. Les equations couplees decrivant le systeme sont solutionnees numeriquement avec la methode de tir. Nous presentons une analyse graphique des quantites pertinentes a l'ecoulement et au transfert de chaleur. Les resultats montrent que l'addition des nanoparticules d'argent reduit considerablement la vitesse et la temperature du fluide. Nous observons une augmentation du transfert de chaleur aux parois pour de grandes fractions en volume de nanoparticules et proposons des suites interessantes a cette etude. [Traduit par la Redaction], 1. Introduction Suspension of nanoparticles of metals in usual heat transfer fluids like water, engine oil, ethylene glycol mixture, etc., has proven a novel technique to enhance the thermal conductivity [...]

The development of in situ chemical sensors is critical for present-day expeditionary oceanography and the new mode of ocean observing systems that we are entering. New sensors take a significant amount of time to develop; therefore, validation of techniques in the laboratory for use in the ocean environment is necessary. Laser-induced breakdown spectroscopy (LIBS) is a promising in situ technique for oceanography. Laboratory investigations on the feasibility of using LIBS to detect analytes in bulk liquids at oceanic pressures were carried out. LIBS was successfully used to detect dissolved Na, Mn, Ca, K, and Li at pressures up to 2.76 x [10.sup.7] Pa. The effects of pressure, laser-pulse energy, interpulse delay, gate delay, temperature, and NaCl concentration on the LIBS signal were examined. An optimal range of laser-pulse energies was found to exist for analyte detection in bulk aqueous solutions at both low and high pressures. No pressure effect was seen on the emission intensity for Ca and Na, and an increase in emission intensity with increased pressure was seen for Mn. Using the dual-pulse technique for several analytes, a very short interpulse delay resulted in the greatest emission intensity. The presence of NaCl enhanced the emission intensity for Ca, but had no effect on peak intensity of Mn or K. Overall, increased pressure, the addition of NaCl to a solution, and temperature did not inhibit detection of analytes in solution and sometimes even enhanced the ability to detect the analytes. The results suggest that LIBS is a viable chemical sensing method for in situ analyte detection in high-pressure environments such as the deep ocean. OCIS codes: 010.4450, 140.3440, 300.6360.

Rapid, size-based, deposition of particles from liquid suspension is demonstrated using the nonuniform electric field created by coplanar microelectrode strips patterned on an insulating substrate. The scheme uses the dielectrophoretic force both to distribute aqueous liquid containing particles and to separate the particles.

An electrochemical technique for growing Fe3O4 nanostructures is presented. Hydrazine and iron compounds in an aqueous solution undergo chemical reactions with hydroxides and form magnetite at the surface of the working electrode of an electrochemical cell.

The characterization of the resonance of electrostatically actuated thin-film hydrogenated amorphous silicon microbridges is presented in air and immersed in aqueous solutions. The resonance frequency of a microbridge operating in aqueous solutions with high electrical conductivities and viscosities is detected.

A study demonstrates the generation of singlet oxygen due to energy transfer from photoexcited silicon nanocrystals in [D.sub.2]O. Experimental findings indicate that the interaction of photogenerated singlet oxygen with the hydrogen-terminated surface of silicon nanocrystals results in photo-oxidation of silicon nanocrystals, and the surface of oxides reduce the photosensitizing efficiency.

The selective excitation of the flexual modes of microcantilevers in aqueous solutions, by applying the photothermal excitation technique is reported. The experiments show that a particular vibration mode could be efficiently excited by focusing the intensity-modulated laser beam on regions of high curvature of the vibration shape.