We introduce a method to enhance the luminescence of GaN-based LEDs by combining the direct heteroepitaxy laterally overgrowth (DHELO) technique with selective wet etching process. The epitaxial overgrowth of GaN layers on sapphire substrate with SiO2 micro-rods array exhibited a reduced dislocation density and improved the crystal quality. The EL intensity of LEDs with SiO2 micro-rods array wa...

This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubu...

The trend to miniaturization cannot be overseen. The use of very small electronic and electro-optical components in a variety of consumer and investment goods is leading to an increasing demand for small-scale servo actuators for micro assembly applications in production equipment. The previous generation of micro gears and micro actuators was not suited to this type of application, because of ...

The miniaturisation of chemical reactors offers many fundamental and practical advantages of relevance to the chemical industry, who are constantly searching for controllable, information rich, high throughput, environmentally friendly methods of producing products with a high degree of chemical selectivity. In this paper a number of chemical reactions will be used to illustrate the advantages ...

An improved micro-reactor cell for IR spectroscopic studies of heterogeneous catalysis was built around a 5.8 GHz microwave cavity. The reactor can operate at 20 bars and with conventional heating up to 720 K, with reactant gas flows velocities (GHSV) from 25,000 to 50,000 h(-1). The temperature of the sample under microwave irradiation was measured by time resolved IR emission spectroscopy. Th...

The scale up of an isothermal micro-trickle bed reactor operated under radio frequency (RF) heating has been performed. The effect of the reactor length, tube diameter and number of parallel tubes on the temperature non-uniformity parameter has been studied. The axial and radial temperature profiles were calculated using a 2D convection and conduction heat transfer problem with heat transfer pr...

Title of Dissertation: STUDY OF CONDENSATION OF REFRIGERANTS IN MICRO-CHANNELS FOR DEVELOPMENT OF FUTURE COMPACT MICRO-CHANNEL CONDENSERS Sourav Chowdhury, Doctor of Philosophy, 2008 Directed By: Professor Michael Ohadi, Department of Mechanical Engineering Miniand microchannel technology has gained considerable ground in the recent years in industry and is favored due to its several advantages...

This study examines the single-phase and two-phase cooling performance of a hybrid micro-channel/micro-jet impingement cooling scheme using HFE 7100 as working fluid. This scheme consists of supplying coolant from a series of jets that deposit liquid into the micro-channels. A single-phase numerical scheme that utilizes the k–e turbulent model and a method for determining the extent of the lami...

Digital microfluidics, which relies on the movement of drops, is relatively immune to clogging problems, making it suited for micro-reactor applications. Here, graphene oxide paper 100 μm thickness, fabricated by blade coating sedimented dispersions onto roughened substrates, followed drying and mechanical exfoliation, was found be free cracks curling. It also exhibited high wettability elasto-...