The anechoic assumption has long been used for the modeling of long exit pipes or ducts of acoustic elements [1, 2, 3, 4, 5, 6, 7]. Especially in compressor discharge line modeling, the exhaust pipe from the compressor manifold leading all the way to the condenser is usually assumed to be anechoic since it is very long. Also, experimental efforts have been made by investigators using different ...

Background In contrast to cigarette smoking, the association between water pipe smoking and airway hyperresponsiveness remains widely unexplored. Methods A bronchoprovocation challenge with mannitol was performed in young adults recruited at the University of Basel, Switzerland. Subjects were categorized as acute water pipe smokers (single episode of water pipe smoking, no or <0.5 pack-years ...

In the present contribution optimization and simulation methods are investigated in order to attain optimal scaling of labial organ pipes. The goal is to determine the optimal dimensions of the pipe, by which a desired steady state sound spectrum can be achieved. By modifying the geometry of the pipe body, the eigenfrequencies of the acoustic resonator can be tuned in order to amplify or repres...

BACKGROUND The Federal excise tax was increased for tobacco products on April 1, 2009. While excise tax rates prior to the increase were the same for roll-your-own (RYO) and pipe tobacco, the tax on pipe tobacco was $21.95 per pound less than the tax on RYO tobacco after the increase. Subsequently, tobacco manufacturers began labeling loose tobacco as pipe tobacco and marketing these products t...

As the front end of intake system, dirty pipe is responsible for delivering sufficient and stable air to filter. Therefore, in order meet requirements low resistance, it necessary correspondingly improve flow resistance performance pipe. In this study, main research object was system gasoline engine vehicles, internal gas field simulated analyzed. The results show that there are clear discrete ...