Acoustics, Dynamics, and Controls Commons^™

Study Of An Axial Fan Combined With A Microperforated Duct, Seungkyu Lee

Seungkyu Lee

The fans used in the ventilation duct systems usually fall into two categories: (i) axial, and (ii) centrifugal. These types of fans are distinguished by having different performance characteristics. For instance, centrifugal fans are capable of generating high static pressures compare to axial fans. However, an axial fan can deal with higher air volume flow rates than a centrifugal fan, and, more importantly, an axial fan produces relatively low fan noise compared to a centrifugal fan. Thus, even though axial fans may be advantageous from a noise point-of-view, they are generally avoided in duct systems when relatively high static pressures …

Full-Field Vibrometry By High-Speed Digital Holography For Middle-Ear Mechanics, Ivo Dobrev

Ivo Dobrev

Hearing loss affects approximately 1 in 10 people in the world and this percentage is increasing every year. Some of the most common courses for hearing loss are disorders of the human tympanic membrane (TM or eardrum) and middle-ear. Early detection and diagnosis of hearing loss as well as research and understanding of the hearing process depend on medical and research tools for quantification of the hearing capabilities, including the function of the human TM in the complex acoustic-mechanical transformation of environmental sounds into vibrations of the middle- and the inner-ear.

Current ear exams are assessing the state of the …

Evaluating Fault Detection And Diagnostics Protocols Applied To Air-Cooled Vapor Compression Air-Conditioners, David P. Yuill, James E. Braun

David Yuill

Fault detection and diagnostics (FDD) tools are being increasingly applied in air-conditioning systems. There are many different protocols used in these FDD tools, so an important question to ask is: how well do the protocols work? This paper describes the ongoing development of the first standardized method of evaluation for FDD protocols applied to air-cooled vapor compression air-conditioning systems. The general approach is to feed a library of data – including temperatures, pressures, and humidity – to a candidate FDD protocol, and observe the responses of the protocol. The library includes data from units operating with no fault or with …