The energy transfer integral between radiating rectangular and detecting circular parallel plates having nonideal angular characteristics is solved for modeling the distance dependence of the irradiance signal. The equation derived for the irradiance signal, which is called the modified inverse-square law, depends on the position, shape, size, and angular characteristics of the light source and...

A new class of diffuser augmented wind turbines (DAWTs) is presented. The new diffuser concept exploits aero-dynamic principles for the creation of high-lift airfoil configurations known from the aircraft industry. Combining this with our objective of obtaining a compact power-efficient design has enabled creation of a family of DAWT designs with energy capture potentials which exceed the power...

This study conducts an experimental study concerning the improvement of nozzle/diffuser micropump design using some novel no-moving-part valves. A total of three micropumps, including two enhancement structures having two-fin or obstacle structure and one conventional micro nozzle/diffuser design, are made and tested in this study. It is found that dramatic increase of the pressure drops across...

Diffused infrared transmission is one of the preferred techniques used in indoor wireless communications. Tolerance to shadowing and a lack of alignm ent requirements are among the many advantages offered by this technique compared to the line-of-sight techniques. However, it has its disadvantages, namely high path loss and multipath dispersion. The limitation imposed by eye-safety requirements...

Joohan Kim Xianfan Xu Purdue University School of Mechanical Engineering West Lafayette, Indiana 47907 E-mail: [email protected] Abstract. Diffuser micropumps are commonly fabricated using the standard lithography techniques with silicon as the base material. The important components of this type of micropumps are flow-directing diffusers and a moving diaphragm. Different diffuser designs show...

The increased performance of close series stacked tube axial fans due to the introduction of a diffuser element between the primary and secondary fan is investigated in this paper. Experimental results showed that there was a 15% increase on average in the performance of two stacked Delta FFB0412VHN 40 mm fans across their operating range when a diffuser element was introduced between the two f...

We investigated the feasibility of designing an Anger-logic PET detector module using large-area high-gain avalanche photodiodes (APDs) for a brain-dedicated PET/MRI system. Using Monte Carlo simulations, we systematically optimized the detector design with regard to the scintillation crystal, optical diffuser, surface treatment, layout of large-area APDs, and signal-to-noise ratio (SNR, define...

This paper uses airflow modeling and particle-tracking methodologies to compare the risk of contaminant deposition on an operating room (OR) surgical site and back table for different ventilation systems. The ventilation system designs considered incorporated commonly used diffuser types, in particular, conventional, laminar, nonaspirating, and displacement diffuser types. Further, a range of d...

The radiometric calibration for the reflective solar bands (RSB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi National Polar-orbiting Partnership (SNPP) platform has reached a mature stage after four years since its launch. The characterization of the vignetting effect of the attenuation screens, the bidirectional reflectance factor of the solar diffuser, the degr...

We develop a reduced order model for large-scale unsteadiness (vortex shedding) in a two-dimensional diffuser and study the mechanisms of active flow separation control. This model can estimate the vortex shedding frequency for inviscid flows by accounting for the accumulated vorticity flux in the diffuser. The model can also predict the stagnation pressure loss, which consists of two parts: A ...