We report on quantum cascade lasers employing waveguides based on a predominant air confinement mechanism in which the active region is located immediately at the device top surface. The lasers employ ridge-waveguide resonators with narrow lateral electrical contacts only, with a large, central top region not covered by metallization layers. Devices based on this principle have been reported in...

Air lubrication is a promising drag reduction technology for ships because it considered to reduce the skin-friction resistance of by changing energy turbulent boundary layers. can be classified into: microbubble (injection microbubbles along hull), air film (using larger cover ship bottom), and cavity (recesses underneath hull are filled with air). In this paper, research progress reviewed fro...

Air sparging (AS) is a commonly applied method for treating groundwater contaminated with volatile organic compounds (VOCs). When using a constant injection of air (continuous mode), a decline in remediation efficiency is often observed, resulting from insufficient mixing of contaminants at the pore scale. It is well known that turning the injection on and off (pulsed mode) may lead to a better...

Maximization of the catalyst efficiency in automotive fuel-injection engines requires the design of accurate control systems to keep the air-to-fuel ratio at the optimal stoichiometric value AF . Unfortunately, this task is complex since the air-to-fuel ratio is very sensitive to small perturbations of the engine parameters. Some mechanisms ruling the engine and the combustion process are in fa...

Fluidized beds are used to gasify materials such as coal or biomass in the production of producer gas. Modeling these reactors using computational fluid dynamics is advantageous when performing parametric studies for design and scale-up. While two-dimensional simulations are easier to perform than threedimensional simulations, they may not capture the proper physics. This paper compares twoand ...

An instrumentation system consisting of driven well-points, instrumentation bundles, and discrete sampling has been developed for monitoring subsurface conditions during the operation of air injection remediation systems. The driven well points provide intimate contact reducing the impact on the remediation process. The instrumentation bundles afford continuous monitoring of subsurface conditio...