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RE: Useful Equations, Formulae, and Constants
Title: Message
too
much! Like Skrable said always: when one gives a formula,
every symbols in the formula must be defined properly and perhaps
with units. No one should guess them unless it is a
mind-hunt game. We all knew that flow velocity in any pipe or
duct are not the same from center of the pipe to the wall surface
(assume it is a cylindrical). Square duct is another story!
Therefore, the following definition V is a
superficial velocity. It is not the same velocity as we used for
speed.
-
casper, chp
Despite the numerous
PhD's and self professed geniuses on this list, I have not seen any actual
help arrive yet. Am I the only poor soul who has to cover the entire
electromagnetic spectrum in my job?
Q=AV. It is a ventilation
equation. Flow rate (Q) = Area (A) x Velocity(V). It is an
equation any Industrial Hygiene Technician would know. I guess most HP's
don't do a lot of field work where they would have to figure out the flow rate
through something, say for instance a fume hood. I'm not poking fun at
you for asking, I'm just amazed that no one seems to have been able to get
this right yet.
As for the UV equation, I have not had to use it
(despite being the Nonionizing Radiation Safety Officer), and frankly hope I
don't have to. You use it for determining effective irradiance
from a broadband UV source. The terms are: Eeff = effective irradiance
relative to a monochromatic source at 270nm in W/cm2. Elambda =Spectral
irradiance in W/cm2. S = relative spectral effectivness (constant for each
wavelength). Delta lambda = bandwidth in nm.You can look in the
back of the ACGIH BEI&TLV handbook for a (rather poor) description of it's
use.
I am not sure what you mean by RF relationships.
Again the ACGIGH handbook has a section on RF or you can go to the IEEE
standard for more detail. I could not locate any use of "Ga". Perhaps
they are referring to Gain which is normally expresses as G (units are
dB). Gain is a numerical value assigned to an antenna that is a
relationship between the size of the antenna, the wavelength it transmits and
its efficiency. In brief: How many wavelengths long is your antenna?
Look here for more (http://www.marcspages.co.uk/tech/antgain.htm).
Good
luck on the test. Maybe someday I will finish my degree and take
it.
At 11:56 AM 6/12/03, you wrote:
Hi present and future
CHPs
Does anyone have the symbols and units defined?
Specifically, I am struggling with Q=AV (charge volts and area?) ,
V=4005radicalVp, (is this ave voltage and peak or something else?), the RF
relationships (such as Ga??), The UV formula (sumationESdelta lambda = Eeff
all are what?), and under Misc. eqs: sigma u squared is what?, and exposure
rate assuming in a mass of some media is in curies? to rad? and includes
build up or not.
Exam date this year is July 21st. Any help is
much appreciated.
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Kim Merritt
Radiation/Laser Safety Officer
HazMed,
Inc.
NASA Langley Research Center
Hampton, VA
(757)864-3210
<mailto:k.merritt@larc.nasa.gov>