2005 ◽  
Vol 6 (1) ◽  
pp. 85-93 ◽  
Author(s):  
H Nakamura ◽  
I Asano ◽  
M Adachi ◽  
J Senda

The Pitot tube flowmetering technique has been used to measure pulsating flow from a vehicle engine exhaust. In general, flowmetering techniques that utilize differential pressure measurements based on Bernoulli's theory are likely to show erroneous readings when measuring an average flowrate of pulsating flow. The primary reason for this is the non-linear relationship between the differential pressure and the flowrate; i.e. the flowrate is proportional to the square root of the differential pressure. Therefore, an average of the differential pressure does not give an average of pulsating flow. In this study, fast response pressure transducers have been used to measure the pulsating pressure. Then the pulsating differential pressure is converted to the flowrate while keeping the pulsation unaveraged. An average flowrate is then calculated in the flowrate domain in order to maintain linearity before and after averaging. The peak amplitude of a pulsation measured here was about 1800 L/min at an average flowrate of 70 L/min when the engine ran at idle speed. This measurement has been confirmed by measuring the pulsation with a gas analyser. The results show a large amount of back and forth gas movement in the exhaust tube. This magnitude of pulsation can cause as much as five times higher erroneous results with the pressure domain averaging when compared to a flowrate domain averaging.


Author(s):  
Denis Andreas Sarigiannis ◽  
Alberto C. Gotti ◽  
Spyros P. Karakitsios

The main issues that pertain to the health burden from waste management and energy resource use are laid out highlighting the aspects that determine actual exposure and the socio-economic conditions that underlie them. Case studies covering biomass burning, acute and chronic exposure to urban and industrial waste are described. They refer to different areas in Europe and socio-economic strata focusing on susceptible population groups, which may be affected by enhanced exposure to environmental toxicants stemming from municipal and industrial waste management and domestic heating or cooking using biomass. These features make socio-economic status and the consequent social (in)justice a key determinant of overall exposure early in life. The latter results in a high probability of onset or exacerbation of adverse health outcomes both in the medium term and later in life. Additional factors that affect the health impacts of environmental exposures comprise choice of diet, education level of parents, access to green or blue space and housing condition.


2012 ◽  
Vol 5 (4) ◽  
pp. 1729-1739 ◽  
Author(s):  
Rutger Dijkstra ◽  
Michael Boot ◽  
Ruud Eichhorn ◽  
David Smeulders ◽  
Johan Lennblad ◽  
...  

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