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RE: RADSAFE digest 2385
The rebreathing time for Xenon-133 lung scans is about 5-7 minutes for
normal patinets and much less for critically ill patients.
> -----Original Message-----
> From: radsafe@romulus.ehs.uiuc.edu [SMTP:radsafe@romulus.ehs.uiuc.edu]
> Sent: Saturday, April 03, 1999 11:19 AM
> To: Multiple recipients of list
> Subject: RADSAFE digest 2385
>
> RADSAFE Digest 2385
>
> Topics covered in this issue include:
>
> 1) Information on Contamination at Wright-Patterson AFB
> by "Jacobus, John (OD)" <JJacobus@exchange.nih.gov>
> 2) Re: CNN Poll (fwd)
> by "Ralph E. Wild" <rewild@ibm.net>
> 3) Need Info on Dose due to Medical Uptake Study
> by "Sewell, Linda" <LMS1@pge.com>
> 4) Re: Need Info on Dose due to Medical Uptake Study
> by Chris Alston <alstonc@odrge.odr.georgetown.edu>
> 5) "Walkie Recordall"
> by "Radiological Health Unit" <raldrich@emi.com>
> 6) Question
> by "Robert D. H. Aft" <AllianceScaff@snet.net>
> 7) Re: Nuclear Train
> by "Michael C. Baker" <mcbaker@lanl.gov>
> 8) Re: Need Info on Dose due to Medical Uptake Study
> by Robert Yoss <ryoss@post.its.mcw.edu>
> 9) Re: Question
> by "Robert D. H. Aft" <AllianceScaff@snet.net>
> 10) RE: Information on Contamination at Wright-Patterson AFB
> by Glen.Vickers@ucm.com
> 11) Job Opportunity
> by "J. Andrew Tompkins" <jatalbq@mindspring.com>
> 12) Re: Crooke's Radiometer
> by "Otto G. Raabe" <ograabe@ucdavis.edu>
> 13) Re: Crooke's Radiometer
> by "Cary Renquist" <crenquis@ktb.net>
> 14) Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space
> by Thomas Gleich Harrison <tomh@jove.acs.unt.edu>
> 15) Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space
> by Thomas Gleich Harrison <tomh@jove.acs.unt.edu>
> 16) Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space
> by Wes Van Pelt <VanPeltW@idt.net>
> 17) RE: Crooke's Radiometer
> by Glen.Vickers@ucm.com
>
> ----------------------------------------------------------------------
>
> Date: Fri, 2 Apr 1999 11:34:27 -0500
> From: "Jacobus, John (OD)" <JJacobus@exchange.nih.gov>
> To: "'RadSafe'" <radsafe@romulus.ehs.uiuc.edu>
> Subject: Information on Contamination at Wright-Patterson AFB
> Message-ID: <B9E892A5AB42D21187AB00805FEA1A2FECEC1E@nihexchange6.nih.gov>
>
> I believe that there was a major contamination problem involving Am-241 at
> Wright-Patterson Air Force Base about 10 or 15 years ago. Does anyone
> remember
> any of the details? -- John
>
> The comments are my own, and do not represent those of my spouse or
> employer.
>
> John Jacobus, Health Physicist
> National Institutes of Health
> Radiation Safety Branch, Building 21, Room 238
> 21 Wilson Drive, MSC 6780
> Bethesda, MD 20892-6780
> Phone: 301-496-5774
> Fax: 301-496-3544
> E-mail: jjacobus@exchange.nih.gov (W)
> jenday@ix.netcom.com (H)
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 12:10:13 -0500
> From: "Ralph E. Wild" <rewild@ibm.net>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Re: CNN Poll (fwd)
> Message-ID: <3704F9F5.E6BD6010@ibm.net>
>
> Thanks. I had found it and given them the benefit of my opinion last
> night before I saw your post of your
> email to CNN. Mine was just a bit more terse and a whole lot less polite
> - not suitable for posting here.
>
> Ralph E. Wild
>
> Craig Johnson wrote:
>
> > The e-mail address for CNN, regarding the cnn.com at least, is
> > cnn.feedback@cnn.com.
> >
> > I already took issue with CNN regarding the use of the word
> "moratorium".
> >
> > At the moment I voted the results were 66% in favour of new contruction
> (or
> > more precisely, "ending the moratorium [sic]") and 33% opposed.
> >
> > Craig Johnson
> >
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 2 Apr 1999 09:55:58 -0800
> From: "Sewell, Linda" <LMS1@pge.com>
> To: "'radsafe@romulus.ehs.uiuc.edu'" <radsafe@romulus.ehs.uiuc.edu>
> Subject: Need Info on Dose due to Medical Uptake Study
> Message-ID:
> <2DE85C3F90E6D111AADC00805FE6FD8D01EDF4D8@exchange401.comp.pge.com>
>
> Hi All,
>
> One of our workers told me he received a lung scan yesterday. He says he
> was given approximately 12 mCi of Xe-133 and 4 mCi of Tc-99m. I know for
> these types of uptakes the effective half-lives are quite short. Anybody
> out there know what the approximate dose is to the lung and the total
> body?
>
> Thanks
>
> Linda
>
>
> Linda M. Sewell, CHP
> Diablo Canyon Power Plant
> PO Box 56
> Avila Beach, CA 93424
> (805) 545-4315 (voice)
> (805) 545-2618 (fax)
> mailto:lms1@pge.com
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 2 Apr 1999 14:30:58 -0500
> From: Chris Alston <alstonc@odrge.odr.georgetown.edu>
> To: radsafe@romulus.ehs.uiuc.edu
> Cc: medphys@lists.wayne.edu
> Subject: Re: Need Info on Dose due to Medical Uptake Study
> Message-ID: <3.0.16.19990402142357.2d77ce66@141.161.237.59>
>
> For Xe-133, it really depends on the rebreathing time. Assuming ten (10)
> minutes (which I think is kind of long, though I eagerly anticipate
> correction on this point), the EDE is 4 mrem/mCi, and the lung dose is 4
> mrad/mCi. Assuming that the Tc-99m was as DTPA, the EDE would have been 22
> mrem/mCi and the lungs would have received 53 mrad/mCi (cf.
> NUREG/CR-6345).
>
> chris a.
>
> At 12:04 04/02/99 -0600, you wrote:
> >Hi All,
> >
> >One of our workers told me he received a lung scan yesterday. He says he
> >was given approximately 12 mCi of Xe-133 and 4 mCi of Tc-99m. I know for
> >these types of uptakes the effective half-lives are quite short. Anybody
> >out there know what the approximate dose is to the lung and the total
> body?
> >
> >Thanks
> >
> >Linda
> >
> >
> >Linda M. Sewell, CHP
> >Diablo Canyon Power Plant
> >PO Box 56
> >Avila Beach, CA 93424
> >(805) 545-4315 (voice)
> >(805) 545-2618 (fax)
> >mailto:lms1@pge.com
> >************************************************************************
> >The RADSAFE Frequently Asked Questions list, archives and subscription
> >information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> >
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 2 Apr 1999 14:27:50 -0500
> From: "Radiological Health Unit" <raldrich@emi.com>
> To: "RADSAFE" <radsafe@romulus.ehs.uiuc.edu>
> Subject: "Walkie Recordall"
> Message-ID: <199904021932.OAA02173@lucas.emi.com>
>
> We recently found a device in a load waste traced to someone cleaning out
> a
> basement. Its a wooden case with dimensions approximately 1ft x 1ft x 6
> in.
> On the front is the label "Walkie Recordall". The top of the case is
> hinged
> and inside is what appears to be a primitive tape recording system. The
> base of the case is a detachable battery pack. The general impression of
> the device is a WWII vintage portable tape recorder.
>
> Radiation readings on the surface of the case are 2-3 mR/h and down inside
> the device (as far as the probe could reach) the readings are around 20
> mR/h. We suspect radium, but this is not confirmed. The person who owned
> the device is believed to have been a flight surgeon in the pacific during
> the War.
>
> Anybody seen one of these things before?
>
> ************************************************************************
> Clayton Bradt, CHP <raldrich@emi.com> phone: 518/457-1202
> Assoc. Radiophysicist fax:
>
> 518/485-7406
> NYS Dept. of Labor
> Radiological Health Unit
> Blg.12, Rm 169
> State Office Campus
> Albany, NY 12240
> ***********************************************************************
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 14:54:07 -0500
> From: "Robert D. H. Aft" <AllianceScaff@snet.net>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Question
> Message-ID: <3705205F.EC0@snet.net>
>
> Are there any facilities out there that are seeking to eliminate or
> reduce inventories of scaffolding used in radiologically controlled
> areas? If so I would like to discuss your efforts with you.
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 13:03:10 -0700
> From: "Michael C. Baker" <mcbaker@lanl.gov>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Re: Nuclear Train
> Message-ID: <4.1.19990402130020.00982320@dippy.lanl.gov>
>
> --=====================_194344979==_.ALT
> Content-Type: text/plain; charset="us-ascii"
>
>
>
> Unfortunately, the way the media works in the US, Rob Lowe is now
> an "expert" on the transport of nuclear materials. When can expect
> to see him interviewed multiple times on the subject.
>
> Mike Baker ... mcbaker@lanl.gov
>
>
>
> >
> > The movie is in May but the time has not been announced. I can't
> remember
> > if it is on CBS or NBC. The movie is called "Atomic Train". The
> preview
> > of the movie showed the train crashing with a nuclear explosion,
> mushroom
> > cloud and the whole bit. Immediately after that explosion Rob Lowe, who
> > plays in this farse, while being interviewed off screen, says
> > "unfortunately, this could happen". So it continues with the
> > misunderstanding of radiation and its uses.
> >
> > Alan Watts
> > RSO
> > Ohio University
>
>
> --=====================_194344979==_.ALT
> Content-Type: text/html; charset="us-ascii"
>
> <html>
> <br>
> <br>
> Unfortunately, the way the media works in the US, Rob Lowe is now <br>
> an "expert" on the transport of nuclear materials. When
> can expect <br>
> to see him interviewed multiple times on the subject.<br>
> <br>
> Mike Baker ... mcbaker@lanl.gov<br>
> <br>
> <br>
> <br>
> <blockquote type=cite cite>The movie is in May but the time has not been
> announced. I can't remember<br>
> if it is on CBS or NBC. The movie is called "Atomic
> Train". The preview<br>
> of the movie showed the train crashing with a nuclear explosion,
> mushroom<br>
> cloud and the whole bit. Immediately after that explosion Rob Lowe,
> who<br>
> plays in this farse, while being interviewed off screen, says<br>
> "unfortunately, this could happen". So it continues with
> the<br>
> misunderstanding of radiation and its uses.<br>
> <br>
> Alan Watts<br>
> RSO<br>
> Ohio University</blockquote></html>
>
> --=====================_194344979==_.ALT--
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 14:10:47 -0600
> From: Robert Yoss <ryoss@post.its.mcw.edu>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Re: Need Info on Dose due to Medical Uptake Study
> Message-ID: <37052446.5887045F@post.its.mcw.edu>
>
> In the old days we used Tc-99m MAA for perfusion ling scans. EDE 4.7 E-2
> rem/mCi. Lung dose 2.5E-1 rad/mCi.
> Ref NUREG/CR-6345
>
> B. Yoss
> ryoss@mcw.edu
>
> Chris Alston wrote:
>
> > For Xe-133, it really depends on the rebreathing time. Assuming ten (10)
> > minutes (which I think is kind of long, though I eagerly anticipate
> > correction on this point), the EDE is 4 mrem/mCi, and the lung dose is 4
> > mrad/mCi. Assuming that the Tc-99m was as DTPA, the EDE would have been
> 22
> > mrem/mCi and the lungs would have received 53 mrad/mCi (cf.
> NUREG/CR-6345).
> >
> > chris a.
> >
> > At 12:04 04/02/99 -0600, you wrote:
> > >Hi All,
> > >
> > >One of our workers told me he received a lung scan yesterday. He says
> he
> > >was given approximately 12 mCi of Xe-133 and 4 mCi of Tc-99m. I know
> for
> > >these types of uptakes the effective half-lives are quite short.
> Anybody
> > >out there know what the approximate dose is to the lung and the total
> body?
> > >
> > >Thanks
> > >
> > >Linda
> > >
> > >
> > >Linda M. Sewell, CHP
> > >Diablo Canyon Power Plant
> > >PO Box 56
> > >Avila Beach, CA 93424
> > >(805) 545-4315 (voice)
> > >(805) 545-2618 (fax)
> > >mailto:lms1@pge.com
> >
> >************************************************************************
> > >The RADSAFE Frequently Asked Questions list, archives and subscription
> > >information can be accessed at
> http://www.ehs.uiuc.edu/~rad/radsafe.html
> > >
> > ************************************************************************
> > The RADSAFE Frequently Asked Questions list, archives and subscription
> > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
>
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 15:15:13 -0500
> From: "Robert D. H. Aft" <AllianceScaff@snet.net>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Re: Question
> Message-ID: <37052551.7A10@snet.net>
>
> Robert D. H. Aft wrote:
> >
> > Are there any facilities out there that are seeking to eliminate or
> > reduce inventories of scaffolding used in radiologically controlled
> > areas? If so I would like to discuss your efforts with you.
> > ************************************************************************
> > The RADSAFE Frequently Asked Questions list, archives and subscription
> > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 2 Apr 1999 15:04:05 -0600
> From: Glen.Vickers@ucm.com
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: RE: Information on Contamination at Wright-Patterson AFB
> Message-ID: <3986C942CB14D11187BB0080D870070A017C6FF3@bwdntxch01.ceco.com>
>
> The way I seem to remember it from a seminar class in college...
>
> A jewler had a significant amount of Am-241 and needed to dispose of it.
> It
> may have been given to someone that worked in the medical establishment on
> base. The material was covertly and improperly stored on the base.
>
> Some workers were in a building accessing drums without appropriate RP
> coverage. I do not believe the drum had adequate written warnings on it
> either. The workers found themselves to be contaminated after accessing
> the
> drums. Not sure if where they detected the contamination, if it was in
> that
> building or at another facility.
>
> They proceeded to a local campground and showered/deconned themselves.
> This
> also happened to be a campground commonly used for the Boy Scouts. I
> believe a new cast acutally mentioned things like "contamination,
> intentional, Boy Scouts". Imagine how that would sound.
>
> The building was deconned and removed.
>
>
> Sincerely,
> Glen Vickers
> glen.vickers@ucm.com
>
>
> -----Original Message-----
> From: Jacobus, John (OD) [SMTP:JJacobus@exchange.nih.gov]
> Sent: Friday, April 02, 1999 10:41 AM
> To: Multiple recipients of list
> Subject: Information on Contamination at Wright-Patterson AFB
>
> I believe that there was a major contamination problem involving
> Am-241 at
> Wright-Patterson Air Force Base about 10 or 15 years ago. Does
> anyone remember
> any of the details? -- John
>
> The comments are my own, and do not represent those of my spouse or
> employer.
>
> John Jacobus, Health Physicist
> National Institutes of Health
> Radiation Safety Branch, Building 21, Room 238
> 21 Wilson Drive, MSC 6780
> Bethesda, MD 20892-6780
> Phone: 301-496-5774
> Fax: 301-496-3544
> E-mail: jjacobus@exchange.nih.gov (W)
> jenday@ix.netcom.com (H)
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and
> subscription
> information can be accessed at
> http://www.ehs.uiuc.edu/~rad/radsafe.html
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 16:22:31 -0500
> From: "J. Andrew Tompkins" <jatalbq@mindspring.com>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Job Opportunity
> Message-ID: <199904022142.QAA27035@smtp4.mindspring.com>
>
> I'm posting this for a friend at SAIC.
>
> >> Employee-owned Science Applications International Corporation (SAIC)
> >> provides high-technology services and products to government and
> >> commercial customers. SAIC and its subsidiaries have estimated annual
> >> revenues of nearly $4 billion and more than 40,000 employees at offices
> in
> >> over 130 cities worldwide. We have the following opportunity available
> at
> >> our MOFFETT FIELD/NASA AMES RESEARCH CENTER location:
>
>
> >> HEALTH PHYSICIST
>
> >> Your duties will include the coordination of staff activities involving
> >> radiation/contamination surveillance, laboratory audits, radiation
> >> dosimetry, laser safety calculations and audits, safety training on
> >> radiation-related subjects, radioactive material receipt and shipping
> >> x-ray device audits, and special projects involving NASA's
> gravitational
> >> biology and other space technology. Requires a BS, MS or Ph.D. in
> health
> >> physics or a related field. Must have current working knowledge and
> 5-10
> >> years of experience. Certified Health Physicist (CHP) is required.
> >> Experience as a Radiation Safety Officer (RSO) on a NRC license is a
> plus.
> >>
> >> SAIC offers a competitive salary and benefits package. For immediate
> >> consideration, mail your resume to Arlene Marston, SAIC/NASA Ames
> Research
> >> Center, M/S 19/21, Moffett Field, CA 94035. You may also fax your
> resume
> >> to (650) 604-2034 or e-mail to amarston@mail.arc.nasa.gov We are an
> >> Affirmative Action Employer who values cultural diversity in the
> >> workplace.
> >>
> >>
> >>
> >> Martin Wizorek, CIH, CSP
> >> Manager, Industrial Hygiene, Training, and Health Physics
> >> Science Applications International Corporation
> >> NASA Ames Research Center, M/S 19-21
> >> Moffett Field, CA 94035-1000
> >> 650/604-3680
> >> FAX 650/604-2034
>
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 16:42:45 -0800
> From: "Otto G. Raabe" <ograabe@ucdavis.edu>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Re: Crooke's Radiometer
> Message-ID: <3.0.1.32.19990402164245.00c49928@peseta.ucdavis.edu>
>
> April 2, 1999
> Davis, CA
>
> The vane radiometer inside a partially evacuated glass bulb works on the
> phenomenon of "thermal creep" as described by Maxwell (J.C. Maxwell, "On
> stress in rarified gases arising from inequalities of temperature,"
> Transactions Royal Society (London) 170:231-245, 1879). Radiation momentum
> is not involved since it is too small.
>
> The forces that arise on the vanes of the radiometer come from the
> so-called "thermal creep" of gas molecules that occurs over the surface of
> an unequally heated body. The black sides of the vanes absorb more heat
> energy from the light than do the white (or silver) sides, so the black
> sides are slightly warmer than the white sides. Gas molecules near a
> surface tend to approach its temperature. The gas molecules diffuse
> preferentially in the direction of increasing temperature (from near the
> white side to near the black side of the vanes). This "thermal creep"
> causes a slight increase in pressure on the warmer (black) sides of the
> vanes. If this force overcomes the static friction at the pivot and the
> air
> resistance, the vanes turn in the direction of faced by the white sides.
>
> For this to work, there must be some gas in the bulb or there would be no
> thermal creep. Clearly, there is an optimum gas concentration. If it is
> too
> low, the pressure caused by the creep would be too small. If it is too
> high, the gas inertial resistance would tend to prevent the vanes from
> readily turning. The gas viscosity affects the magnitude of the therml
> creep, but is not a major variable because it is nearly independent of gas
> pressure.
>
> Otto
> *****************************************************
> Prof. Otto G. Raabe, Ph.D., CHP
> Institute of Toxicology & Environmental Health (ITEH)
> (Street address: Building 3792, Old Davis Road)
> University of California, Davis, CA 95616
> Phone: 530-752-7754 FAX: 530-758-6140
> E-mail ograabe@ucdavis.edu
> *****************************************************
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Fri, 02 Apr 1999 22:07:58 -0800 (PST)
> From: "Cary Renquist" <crenquis@ktb.net>
> To: "radsafe@romulus.ehs.uiuc.edu" <radsafe@romulus.ehs.uiuc.edu>
> Subject: Re: Crooke's Radiometer
> Message-ID: <199904030608.WAA23943@comet.ktb.net>
>
> I guess that this is one of those sort-of-off-topic-posts,
> but I just have to say: This is what I love about the
> internet and resources such as RadSafe... an off-hand reference
> comes up, and Pow! an instant response with a great web-connection.
>
> Cary
>
> On Fri, 2 Apr 1999 09:34:42 -0600 (CST), Falo Gerald A wrote:
> Here is a link to a detailed explanation of the Crooke's radiometer or
> Light
> Mill.
> >http://www.public.iastate.edu/~physics/sci.physics/faq/light-mill.html
> :.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:
> Cary Renquist crenquis@ktb.net
> :.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Sat, 3 Apr 1999 01:59:35 -0600 (CST)
> From: Thomas Gleich Harrison <tomh@jove.acs.unt.edu>
> To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject: Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space
> Message-ID: <Pine.GSO.3.96.990403014850.16777A-100000@jove.acs.unt.edu>
>
>
> well lets face it.. the workings of Crooke's Radiometer is a scientific
> mystery. But all of the above are probably correct. Electrons clearly must
> absorb the radiant energy and thus aquire added momentum. If the light
> energy is such that the work function can be overcome, then of course
> electrons will leave the surface. Or if the thermal distribution can be
> shifted slightly upscale then more electrons will exceed the threshold for
> escape and thus more will leave the surface then if the temp is lower.
> My original point is that like energy, momentum can be nether created nor
> destroyed, just transferred and partitioned. So if electrons leave the
> surface with momentum, then the photons striking the surface had to have
> initial momentum......... I think !!!
>
> Tom Harrison
> Physics Dept
> University of North Texas
>
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
>
> ------------------------------
>
> Date: Sat, 3 Apr 1999 02:26:36 -0600 (CST)
> From: Thomas Gleich Harrison <tomh@jove.acs.unt.edu>
> To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject: Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space
> Message-ID: <Pine.GSO.3.96.990403021833.16777D-100000@jove.acs.unt.edu>
>
>
> Good explanation on the webb site address and from Otto Raabe, good
> reading so I stand corrected on direct momentum transfer. I've learned one
> thing.....read on before responding...... I could learn somehthing... !!
> Thanks.........'
>
> Tom Harrison
> Engineering Physics
> University of North Texas
>
>
> On Sat, 3 Apr 1999, Thomas Gleich Harrison wrote:
>
> >
> > well lets face it.. the workings of Crooke's Radiometer is a scientific
> > mystery. But all of the above are probably correct. Electrons clearly
> must
> > absorb the radiant energy and thus aquire added momentum. If the light
> > energy is such that the work function can be overcome, then of course
> > electrons will leave the surface. Or if the thermal distribution can be
> > shifted slightly upscale then more electrons will exceed the threshold
> for
> > escape and thus more will leave the surface then if the temp is lower.
> > My original point is that like energy, momentum can be nether created
> nor
> > destroyed, just transferred and partitioned. So if electrons leave the
> > surface with momentum, then the photons striking the surface had to have
> > initial momentum......... I think !!!
> >
> > Tom Harrison
> > Physics Dept
> > University of North Texas
> >
> >
> > ************************************************************************
> > The RADSAFE Frequently Asked Questions list, archives and subscription
> > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> >
>
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> ------------------------------
>
> Date: Sat, 03 Apr 1999 07:29:34 -0500
> From: Wes Van Pelt <VanPeltW@idt.net>
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: Re: Nuclear Isomer Decay: A Possibility for Breakthrough Space
> Message-ID: <370609AE.108799B0@idt.net>
>
> Thomas Gleich Harrison wrote:
>
> > snip.....
> > My original point is that like energy, momentum can be nether created
> nor
> > destroyed, just transferred and partitioned. So if electrons leave the
> > surface with momentum, then the photons striking the surface had to have
> > initial momentum......... I think !!!
> >
> > Tom Harrison
> > Physics Dept
> > University of North Texas
>
> Tom and All,
>
> Just a point on the physics here. There is no such thing as conservation
> of
> momentum. Think about it. If two pool balls come directly together with
> the
> same speed (opposite veolcities) they both stop. They each had momentum
> before the collission. And after the collision, there is no momentum.
> The
> momentum is gone. (Just like Bob Dole's presidential campaign.)
>
> Wes
> --
> Wesley R. Van Pelt, Ph.D., CIH, CHP KF2LG
> President, Van Pelt Associates, Inc.
> Consulting in radiological health and safety.
> mailto:VanPeltW@IDT.net http://shell.idt.net/~vanpeltw/index.html
>
>
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>
> ------------------------------
>
> Date: Sat, 3 Apr 1999 07:17:49 -0600
> From: Glen.Vickers@ucm.com
> To: radsafe@romulus.ehs.uiuc.edu
> Subject: RE: Crooke's Radiometer
> Message-ID: <3986C942CB14D11187BB0080D870070A017C6FF4@bwdntxch01.ceco.com>
>
> I haven't followed this thread to closely, but I believe this is commonly
> described in physics textbooks. If this is the little dealy with the
> black
> and white sided vanes that turn when exposed to light, I believe it does
> indeed work on the principles of differential thermal absorption by the
> different colors and increased gas pressure on the black or warmer side.
>
> Obviously a physics professor would make students postulate how it works
> before telling them...
>
> Sincerely,
> Glen
> glen.vickers@ucm.com
>
> -----Original Message-----
> From: Otto G. Raabe [SMTP:ograabe@ucdavis.edu]
> Sent: Friday, April 02, 1999 6:50 PM
> To: Multiple recipients of list
> Subject: Re: Crooke's Radiometer
>
> April 2, 1999
> Davis, CA
>
> The vane radiometer inside a partially evacuated glass bulb works on
> the
> phenomenon of "thermal creep" as described by Maxwell (J.C. Maxwell,
> "On
> stress in rarified gases arising from inequalities of temperature,"
> Transactions Royal Society (London) 170:231-245, 1879). Radiation
> momentum
> is not involved since it is too small.
>
> The forces that arise on the vanes of the radiometer come from the
> so-called "thermal creep" of gas molecules that occurs over the
> surface of
> an unequally heated body. The black sides of the vanes absorb more
> heat
> energy from the light than do the white (or silver) sides, so the
> black
> sides are slightly warmer than the white sides. Gas molecules near a
> surface tend to approach its temperature. The gas molecules diffuse
> preferentially in the direction of increasing temperature (from near
> the
> white side to near the black side of the vanes). This "thermal
> creep"
> causes a slight increase in pressure on the warmer (black) sides of
> the
> vanes. If this force overcomes the static friction at the pivot and
> the air
> resistance, the vanes turn in the direction of faced by the white
> sides.
>
> For this to work, there must be some gas in the bulb or there would
> be no
> thermal creep. Clearly, there is an optimum gas concentration. If it
> is too
> low, the pressure caused by the creep would be too small. If it is
> too
> high, the gas inertial resistance would tend to prevent the vanes
> from
> readily turning. The gas viscosity affects the magnitude of the
> therml
> creep, but is not a major variable because it is nearly independent
> of gas
> pressure.
>
> Otto
>
> *****************************************************
> Prof. Otto G. Raabe, Ph.D., CHP
> Institute of Toxicology & Environmental Health (ITEH)
> (Street address: Building 3792, Old Davis Road)
> University of California, Davis, CA 95616
> Phone: 530-752-7754 FAX: 530-758-6140
> E-mail ograabe@ucdavis.edu
> *****************************************************
>
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> ------------------------------
>
> End of RADSAFE Digest 2385
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