At 12:47 pm 24/08/2005 -0500, you wrote:
>Michael Huffman wrote:
>
>> Grimer wrote:
>>
>>>
>>> You could have added Casimir pressure for good measure. 8-)
>>>
>>> My preferred term is Beta-atmosphere since I find the analogy
>>> with atmospheric pressure useful - and it arises naturally if
>>> one starts one's analysis with sands and clays which are held
>>> together by Alpha-atmospheric pressure in the case of coarse
>>> sands (pF < 15 psi) and Beta-atmospheric pressure in the case
>>> of clays, say. (pF > 15 psi).
>>
>> Moin Frank,
>>
>> So, you are basically changing the baseline for pressure to 15psi, but
>> you do still agree with the majority of the scientific community, that
>> all pressure is positive with relation to no pressure, and that there is
>> no such thing as negative pressure with relation to no pressure.
>>
>> Knuke
>>
>
>
>Assuming negative pressure is possible, what would that imply?
>
>Harry
It would imply you are working from the wrong datum for zero
pressure - something analogous to working from the wrong
datum for the motion of the sun and planets or the wrong datum
for temperature.
Historically, people have always started from an anthropomorphic
datum. It is the natural thing to do. For example, they set the
datum for temperature at O degrees Centigrade. Eventually the
maths of the relation between temperature and volume for gases
showed them what datum they should start from. This is exactly
what happened to Hewitt and I in relation to stress on concrete,
water, etc., as you will see if you care to read....
==================================================
GRIMER, F.J. and R.E.HEWITT. The form of the
stress-strain curve of concrete interpreted
with a di-phase concept of material behaviour.
Structure, Solid Mechanics and Engineering Design.
Proceedings of the Southampton 1969 Civil
Engineering Conference. (M.Te'eni, Ed.),
Wiley Interscience, pp 681 - 691, 1972.
===================================================
......which you will find in the "Files" section at
the following location.
http://groups.yahoo.com/group/Beta-atmosphere_group/
Frank Grimer
