Re: Useful Equations, Formulae, and Constants

["Kim D. Merritt" <k.merritt@larc.nasa.gov>]

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. 
>
>  
>
>
>
> Do you Yahoo!?
>
> Free
>
> online
>
> calendar with sync to Outlook(TM).

Kim Merritt
Radiation/Laser Safety Officer
HazMed, Inc.
NASA Langley Research Center
Hampton, VA
(757)864-3210
<mailto:k.merritt@larc.nasa.gov>