Genetic approaches (e.g. mutation, RNA interference) in model organisms, particularly the nematode Caenorhabditis elegans, have yielded a wealth of information on cellular processes that can influence lifespan. Although longevity mutants discovered in the lab are instructive of cellular physiology, lab studies might miss important genes that influence health and longevity in the wild. C. elegan...

The flows of heat and electricity in a column-type micro-thermoelectric cooler are analyzed by modeling the various interfacial resistances. Electron (barrier tunneling) and phonon (diffuse mismatch) boundary resistances at the thermoelectric/metal interface, and thermal non-equilibrium between electrons and phonons adjacent to this interface (cooling length), increase the thermal conduction re...

Particle effects on friction and wear of 6061 aluminium (6061 AI) reinforced with silicon carbide (SIC) and alumina (AI203) particles were investigated by means of Vickers microhardness measurements and scratch tests. Unreinforced 6061 AI matrix alloy was also studied for comparison. To explore the effect of heat treatment, materials subjected to three different heat treatment conditions, i.e. ...

The purpose of brake is to decelerate a vehicle by transforming the kinetic energy of the vehicle to heat via friction and dissipating that heat to the surroundings. As a part of an automobile, brake materials have additional requirements like resistance to corrosion, light weight, long life, low noise, stable friction, low wear rate and acceptable cost versus performance. Selection of the mate...

This paper presents micromachined thermal sensors for measuring liquid flow rates in the nanoliter-per-minute range. The sensors use a boron-doped polysilicon thinfilm heater that is embedded in the silicon nitride wall of a microchannel. The boron doping is chosen to increase the heater’s temperature coefficient of resistance within tolerable noise limits, and the microchannel is suspended fro...

Bubble columns are gas- liquid contactors that are widely used in chemical and bio- chemical industries. High mixing that result in high heat and mass transfer rates are amongst their advantages. Heat transfer in a bubble column having a bundle of heaters investigated and the variation of heat transfer coefficient with variation in heaters pitch to diameter ratios in a bundle of heaters reporte...

1 his paper provides a U-J;P,G work for selecting heat exchangers materials especially those used in nuclear power plants. Typical examples of materials selection for heat exchanger tubing of nuclear power plants and condensers are presented. The paper brings out also, the importance of continued intensive R & D in materials in order to enhance the reliability and reduce cost by improving upon ...

Heat exchangers: types .................................................................................................................................. 1 Plate heat exchangers ................................................................................................................................ 4 Shell-and-tube heat exchangers ............................................................

laminar free convection heat transfer from vertical and inclined arrays of horizontal isothermal cylinders in air was investigated experimentally and numerically. experiments were carried out using mach-zehnder interferometer and the fluent code was used for numerical study. investigation was performed for vertical and horizontal cylinder spacing from 2 to 5 and 0 to 2 cylinder diameters respec...

Heat exchangers: types .................................................................................................................................. 1 Plate heat exchangers ................................................................................................................................ 4 Shell-and-tube heat exchangers ............................................................