Date: Fri, 8 Aug 2003 12:46:41 -0500

Author: "Karl I. Trappe"

Subject: Re: Gas Pains

Post:

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I agree with Sam about the testing. If the cylinder is within its
test date, then it does not need retesting.

Different cylinders have different retest periods. Most are either 5
or 10 years. I believe that the retest period is determined by the
Department of Transportation because they have to pass interstate
transport rules. The tank is filled under water to a pressure about
3 (?) times its rated value, etc, etc. Then it is restamped with a
new date. Rarely will the cylinders fail, unless they are poorly
treated (like leaving them in the rain or in a puddle).

So the bottom line is: Retesting is a 5 to 10 year investment.
Refilling is on an "as needed" basis. To amortize the retesting, use
the cylinders up and refill them frequently. This assumes that you
have found a place that will cut you a deal on refilling.

*IF* the cylinders are marked as fire extinguishers, there may be
additional testing regulations *because of their intended use*. This
could be circumvented by using a generic cylinder. I understand
Scuba cylinders can be used. Probably, repainting will be required
to fill them with C02.

Karl

>Cliff,
>
>In NYS, our tanks need to tested every 10 years. So it's the law
>that determines when they need to be tested. I'd argue with them
>and see what's up.
>
>Sam
>
>Cliff Bettis wrote:
>
>>Sam,
>>
>>Maybe that's it: in the past they haven't done the pressure test. Is there
>>any reason they should? I'll see if I can get them to fill it without the
>>test. Otherwise $20 bucks a demo is a bit steep (I get about two uses out of
>>the 35 lb. cylinders)
>>
>>Cliff
>>
>>----- Original Message -----
>>From: "Sam Sampere"
>>To:
>>Sent: Friday, August 08, 2003 10:51 AM
>>Subject: Re: Gas Pains
>>
>>
>>
>>
>>>I just had mine filled for the same price as last year. I think for
>>>$45, you get a fill and a pressure test.
>>>
>>>sam
>>>
>>>Cliff Bettis wrote:
>>>
>>>
>>>
>>>>Hi All,
>>>>
>>>>I am getting ready for the Fall Semester and was about to have my CO2
>>>>cylinders recharged and found the supplier now wants $45 a cylinder. I am
>>>>looking for another supplier but I was wondering is anyone else having
>>>>
>>>>
>>this
>>
>>
>>>>problem?
>>>>
>>>>Cliff
>>>>
>>>>
>>>>

--
Dr. Karl I. Trappe Desk (512) 471-4152
Lecture Demonstration Office Office (512) 471-5411
Physics Department, Mail Stop C-1600 Home (512) 264-1616
The University of Texas at Austin
Austin, Texas 78712-1081
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Re: Gas Pains

I agree with Sam about the testing.  If the cylinder is
within its test date, then it does not need retesting.



Different cylinders have different retest periods.  Most are
either 5 or 10 years.  I believe that the retest period is
determined by the Department of Transportation because they have to
pass interstate transport rules.  The tank is filled under water
to a pressure about 3 (?) times its rated value, etc, etc.  Then
it is restamped with a new date.  Rarely will the cylinders fail,
unless they are poorly treated (like leaving them in the rain or in a
puddle).



So the bottom line is:  Retesting is a 5 to 10 year
investment.  Refilling is on an "as needed" basis. 
To amortize the retesting, use the cylinders up and refill them
frequently.  This assumes that you have found a place that will
cut you a deal on refilling.



*IF* the cylinders are marked as fire extinguishers, there may be
additional testing regulations *because of their intended use*. 
This could be circumvented by using a generic cylinder.  I
understand Scuba cylinders can be used.  Probably, repainting
will be required to fill them with C02.



Karl



Cliff,



In NYS, our tanks need to tested every 10 years.  So it's the law
that determines when they need to be tested.  I'd argue with them
and see what's up.



Sam



Cliff Bettis wrote:

Sam,



Maybe that's it: in the past they haven't done the pressure test. Is
there

any reason they should? I'll see if I can get them to fill it without
the

test. Otherwise $20 bucks a demo is a bit steep (I get about two uses
out of

the 35 lb. cylinders)



Cliff



----- Original Message -----

From: "Sam Sampere"
href="mailto:sampere@physics.syr.edu"><sampere@physics.syr.edu> >

To:
href="mailto:tap-l@listproc.appstate.edu"> ><tap-l@listproc.appstate.edu>


Sent: Friday, August 08, 2003 10:51 AM

Subject: Re: Gas Pains





 


I just had mine filled for the same
price as last year.  I think for

$45, you get a fill and a pressure test.



sam



Cliff Bettis wrote:



   


Hi All,



I am getting ready for the Fall Semester and was about to have my
CO2

cylinders recharged and found the supplier now wants $45 a cylinder. I
am

looking for another supplier but I was wondering is anyone else
having

     





this

 



problem?



Cliff





     







--

Dr. Karl I.
Trappe           >           
Desk (512) 471-4152

Lecture Demonstration
Office           
Office (512) 471-5411

Physics Department, Mail Stop C-1600    Home (512)
264-1616

The University of Texas at Austin

Austin, Texas 78712-1081



--============_-1151757692==_ma============--
From stjohn@buphy.bu.edu Fri Aug 8 13:56:59 2003
Date: Fri, 8 Aug 2003 13:58:30 -0400
From: "Jason St. John"
To:
Subject: Re: particle nature: dim photograph
In-Reply-To:
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Thanks very much, folks. Once again, tap-l is the greatest resource of
resourcefulness. (Take that, Goedel!)

____________________________________________________
Jason St. John 617.353.2634 stjohn@bu.edu
Boston University Physics Lecture Demonstrations
590 Commonwealth Ave. Boston, MA 02215

On 2003-08-07.13:59 owner-tap-l@listproc.appstate.edu sent:

I would think that to demonstrate the particle nature of light with
film, the film must be ultra high speed so that single photons are
capable of energizing a single grain. No, he hasn't invented this --
see for example fig 10.11 of R.E.I. Newton's book "Wave Physics."
Such examples have appeared in many texts. Wolfgang


>I have a faculty member in my office who is wondering if he has invented
>this:
>
>A photograph in dim ambient light that shows speckling. Can this be done
>with a polaroid, maybe? Is it also possible to do with severe
>attentuation, say, maybe by neutral density filters?
>
>As ever,
>____________________________________________________
>Jason St. John 617.353.2634 stjohn@bu.edu
>Boston University Physics Lecture Demonstrations
>590 Commonwealth Ave. Boston, MA 02215
From cablem@wfu.edu Fri Aug 8 14:06:54 2003
Message-ID: <3F33E71A.4030702@wfu.edu>
Date: Fri, 08 Aug 2003 14:08:26 -0400
From: Machele Cable
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To: tap-l@listproc.appstate.edu
Subject: Re: Gas Pains
References: <00c601c35dc3$f9ae2010$96245d81@lecturedemo> <3F33C717.4030200@physics.syr.edu> <00d701c35dc7$6f0d17f0$96245d81@lecturedemo> <3F33D08F.5090802@physics.syr.edu>
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If you paint the cylinders some other color other than RED and clearly
label them as DEMO equipment, then do they HAVE to be tested as fire
safety equipment (and thus you account billed for the test)???? Ours are
merely weighed to check the charge...and done by the safety guy here on
campus.

Chele



Sam Sampere wrote:

> Cliff,
>
> In NYS, our tanks need to tested every 10 years. So it's the law that
> determines when they need to be tested. I'd argue with them and see
> what's up.
>
> Sam
>
> Cliff Bettis wrote:
>
>>Sam,
>>
>>Maybe that's it: in the past they haven't done the pressure test. Is there
>>any reason they should? I'll see if I can get them to fill it without the
>>test. Otherwise $20 bucks a demo is a bit steep (I get about two uses out of
>>the 35 lb. cylinders)
>>
>>Cliff
>>
>>----- Original Message -----
>>From: "Sam Sampere"
>>To:
>>Sent: Friday, August 08, 2003 10:51 AM
>>Subject: Re: Gas Pains
>>
>>
>>
>>
>>>I just had mine filled for the same price as last year. I think for
>>>$45, you get a fill and a pressure test.
>>>
>>>sam
>>>
>>>Cliff Bettis wrote:
>>>
>>>
>>>
>>>>Hi All,
>>>>
>>>>I am getting ready for the Fall Semester and was about to have my CO2
>>>>cylinders recharged and found the supplier now wants $45 a cylinder. I am
>>>>looking for another supplier but I was wondering is anyone else having
>>>>
>>>>
>>this
>>
>>
>>>>problem?
>>>>
>>>>Cliff
>>>>
>>>>
>>>>
>>>>

--
~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~
Machele Cable Lab Manager Physics WFU
Phone: (336) 758-5532 Fax: (336) 758-6142
~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~
Friends are the Bacon Bits in the salad bowl of life.
~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~
There's a thin woman inside of me trying to get out,
but I can usually shut her up with some chocolate!


From cablem@wfu.edu Fri Aug 8 14:09:50 2003
Message-ID: <3F33E7C8.6070001@wfu.edu>
Date: Fri, 08 Aug 2003 14:11:20 -0400
From: Machele Cable
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Subject: Looking for Bill Reitz
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Bill Reitz....

Could you contact me off-list, please??? You forgot to get your Sutton
CD from the resource room!

Chele


--
~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~
Machele Cable Lab Manager Physics WFU
Phone: (336) 758-5532 Fax: (336) 758-6142
~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~
Friends are the Bacon Bits in the salad bowl of life.
~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~ - ~
There's a thin woman inside of me trying to get out,
but I can usually shut her up with some chocolate!

From sampere@physics.syr.edu Fri Aug 8 14:16:29 2003
Message-ID: <3F33E913.3040101@physics.syr.edu>
Date: Fri, 08 Aug 2003 14:16:51 -0400
From: Sam Sampere
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To: tap-l@listproc.appstate.edu
Subject: Re: Gas Pains
References: <00c601c35dc3$f9ae2010$96245d81@lecturedemo> <3F33C717.4030200@physics.syr.edu> <00d701c35dc7$6f0d17f0$96245d81@lecturedemo> <3F33D08F.5090802@physics.syr.edu> <3F33E71A.4030702@wfu.edu>
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Mine are painted yellow and clearly labeled in large letters "Physics
Demonstration Only". Even though the intended use is clearly not fire
fighting, they still need to be checked. For fun, check other
cylinders in your department (He, Ar, N2, O2, etc.), and you will see
stamps around those necks too.

Sam

Machele Cable wrote:

> If you paint the cylinders some other color other than RED and clearly
> label them as DEMO equipment, then do they HAVE to be tested as fire
> safety equipment (and thus you account billed for the test)???? Ours
> are merely weighed to check the charge...and done by the safety guy
> here on campus.
>
> Chele
>
>
>
> Sam Sampere wrote:
>
>> Cliff,
>>
>> In NYS, our tanks need to tested every 10 years. So it's the law
>> that determines when they need to be tested. I'd argue with them and
>> see what's up.
>>
>> Sam
>>
>> Cliff Bettis wrote:
>>
>>> Sam,
>>>
>>> Maybe that's it: in the past they haven't done the pressure test. Is
>>> there
>>> any reason they should? I'll see if I can get them to fill it
>>> without the
>>> test. Otherwise $20 bucks a demo is a bit steep (I get about two
>>> uses out of
>>> the 35 lb. cylinders)
>>>
>>> Cliff
>>>
>>> ----- Original Message ----- From: "Sam Sampere"
>>>
>>> To:
>>> Sent: Friday, August 08, 2003 10:51 AM
>>> Subject: Re: Gas Pains
>>>
>>>
>>>
>>>
>>>> I just had mine filled for the same price as last year. I think for
>>>> $45, you get a fill and a pressure test.
>>>>
>>>> sam
>>>>
>>>> Cliff Bettis wrote:
>>>>
>>>>
>>>>
>>>>> Hi All,
>>>>>
>>>>> I am getting ready for the Fall Semester and was about to have my CO2
>>>>> cylinders recharged and found the supplier now wants $45 a
>>>>> cylinder. I am
>>>>> looking for another supplier but I was wondering is anyone else
>>>>> having
>>>>>
>>>>
>>> this
>>>
>>>
>>>>> problem?
>>>>>
>>>>> Cliff
>>>>>
>>>>>
>>>>>
>>>>
>
From dwilley+@pitt.edu Fri Aug 8 14:31:09 2003
Date: Fri, 08 Aug 2003 14:32:30 -0400
From: David Willey
Subject: Re: glass
To: tap-l@listproc.appstate.edu
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Organization: University of Pittsburgh
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Walking on broken glass.
For this demonstration the glass bottles should first be soaked in water so as
to remove any paper labels, an alternative to this is to use Mason Jars. It is
best to use fairly large bottles so that the pieces formed will have only a
gentle curve to them. When breaking the bottles I place them in a canvas sack
and use a hammer, being sure to wear gloves and eye protection. The glass
should be broken into fairly small pieces. The bed for the glass may be made
from half inch thick plywood framed by pieces of 2 x 4. Once the glass has
been poured into the bed it should be spread out so as to form a layer of
uniform depth. Any piece that has a right angled bend in it, where the sidewall
of the bottle meets the base of the bottle, is moved to the edges of the bed,
so that only relatively flat pieces of glass are included in the center of the
bed where the walking takes place. As an extra precaution when performing this
demonstration, I cover the glass with a cloth and then use a large cast iron
skillet to pound the surface firmly. This ensures no points of glass are
sticking up. This is usually done before any audience enters the room. A bed of
glass about 8 cm deep seems best, as this provides sufficient depth for the
glass to be able to shift and settle somewhat, as a foot is planted slowly and
directly down upon it. When done this way the pieces of glass lay fairly flat
and no edge presses perpendicularly against the sole. The bottom of the foot
has some give to it and conforms to the shallow curve of the glass pieces. This
is similar to a sharp knife being pressed with the flat of the blade against
ones flesh, where considerable force may be used without injury ensuing,
whereas if the edge of the knife is used, a cut is likely. When walking I
place each foot slowly into place moving it to another place if a point or edge
is felt, although that is seldom necessary if the bed has been prepared
correctly. Care must be taken to brush off any pieces of glass that stick to
the bottom of the feet as the step off the bed is taken.
To show that the edges of the glass are sharp I use a piece from the bed to
cut the string suspending a bowling ball about a half meter above the floor.
In my opinion this is a good attention getter, but not a good Physics demo.
Wear goggles when the break the stick on the glasses and don't have students
anywhere close, splinters can fly off 20 to 30 ft, I've had it happen. Video
tape it would be my advise,
cheers,
David

Flora Shepherd wrote:

> Hello all,
>
> Can anyone offer me some advice on walking on glass? I'm a little
> unsure of how to make it consistently safe.
>
> Also, I've seen a demo where someone places a dowel with pins over
> wineglasses, then breaks the dowel, but I don't remember the specifics.
> Any suggestions?
>
> The first draft of our website is up! Please check it out and email me all
> your suggestions. And feel free to link us to your site.
>
> http://www.brynmawr.edu/Acads/Physics/MNoel/bop/home/home.htm
>
> Thanks a lot,
> Flora

From anthony_lapinski@pds.org Fri Aug 8 14:47:23 2003
Message-id:
Date: Fri, 08 Aug 2003 14:51:23 -0400
Subject: using PED's on planes
To: tap-l@listproc.appstate.edu
From: "Anthony Lapinski"
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As I was flying back to Jersey from Madison, I heard the flight attendants
say that portable electronic devices could not be used at certain times
(usually before/during/after takeoff, and well before landing). I guess
radio transmissions between the ground and pilot may get disrupted. I can
see why operating a cell phone would not be good, but what about other
devices such as walkman's, CD players, computers, and portable electronic
games? How could playing a battery-operated CD player interfere with
anything?
From bjones@lamar.colostate.edu Fri Aug 8 15:20:30 2003
Mime-Version: 1.0

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