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Guy Macon's adventures with ultrapure water

K

Ken Smith

Jan 1, 1970
0
Very like RO. In RO, you drill little holes in some plastic so that only
liquid water can get through. Drilling the plastic is harder because the
little bitty drill bit get stuck more easily.

But what if you use a thinner cutting lubricate, like
used for thread tapping instead of regular cutting oil.[/QUOTE]

After you are done you have to clean out the hole. A chemical company
could make some:



C = C H H H H H H H H
// \\ ! ! ! ! ! ! ! !
C C = C = C = C = C = C - C - C - C - C - C - C - C - H
\\ // ! ! ! ! ! ! !
C = C H H H H H H H
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Ken Smith
After you are done you have to clean out the hole. A chemical company
could make some:



C = C H H H H H H H H
// \\ ! ! ! ! ! ! ! !
C C = C = C = C = C = C - C - C - C - C - C - C - C - H
\\ // ! ! ! ! ! ! !
C = C H H H H H H H

1-cyclohexylbutynyl-4-octane (approximately)

I think the butynyl might make it a bit costly. You might need a couple
of chlorines on that terminal methyl, to prevent it swallowing its tail.
This would compromise its efficiency as a bottle-brush rather
decisively.
 
R

Rich Grise

Jan 1, 1970
0
Excellent questions, but this is just about what they do to create
reverse osmosis membranes. I worked for a while in a plant that made
them (Permasep). The chemistry and processing is quite difficult to
get membranes with those quadrillions of correct sized holes. The
surface properties (hydrophilic versus hydrophobic) of the holes is
important also.

They use plastic materials not quartz, though.

Something I'd like to find out how it works is "molecular sieve". In my
Dad's waning years, he needed supplemental oxygen. Well, a tank of oxygen
every few days can get expensive, but an "oxygen concentrator", used, is
about four hundred bucks.

Apparently, it literally pushes air through some stuff that separates the
nitrogen from the oxygen, throws the nitrogen out, and outputs better than
95% pure O2. That's some pretty tiny holes, and they must be very precise
to distinguish O2 from N2 by size.

Thanks,
Rich
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Ken Smith


1-cyclohexylbutynyl-4-octane (approximately)

I think the butynyl might make it a bit costly. You might need a couple
of chlorines on that terminal methyl, to prevent it swallowing its tail.
This would compromise its efficiency as a bottle-brush rather
decisively.

OPEN THE POD BAY DOOR HAL!!!!!!!!!!!!!

<erk>
 
B

Borek

Jan 1, 1970
0
Ken said:
After you are done you have to clean out the hole. A chemical company
could make some:



C = C H H H H H H H H
// \\ ! ! ! ! ! ! ! !
C C = C = C = C = C = C - C - C - C - C - C - C - C - H
\\ // ! ! ! ! ! ! !
C = C H H H H H H H

Hexavalent carbon? Get real, man ;)

Best,
Borek
 
P

Paul Burke

Jan 1, 1970
0
Borek said:
Hexavalent carbon? Get real, man ;)

Probably billion-year old carbon from Woodstock, and its memory is
getting a bit unreliable.

Paul Burke
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Borek
Hexavalent carbon? Get real, man ;)
Oops! I didn't notice that, either. Make that a heterocyclic ring.


C = N
// \
C C=
\\ /
C = N
 
G

Guy Macon

Jan 1, 1970
0
n2mp said:
Yes, everything talked about above will happen in a conductivity
meter, and in any system involving electrochemical reactions, as
far as current is flowing in the solution.

I was under the impression that a conductivity meter measuring
ultrapure water doesn't have any electrochemical reactions.
: is the AC signal in a conductivity meter adjusted so that no
electrochemical reaction occur at the electrode ?

The one I designed (which was low-cost and low-accuracy)
simply took a DC reading, then took another DC reading with
polarity reversed. That worked fine.

From my webpage at [ http://www.guymacon.com/SMC/INDEX.HTM ]:

"...One interesting technical challenge was measuring the
resistivity of the water. 100% pure water has a bulk
resistivity of around 18 Megohms per cubic centimeter. This
resistivity is also strongly affected by the temperature of
the water. A Microcontroller has the ability to measure
resistance by measuring the rise-time of a digital pulse
through an RC circuit, but the range it measures is usually
only a few Kilohms, not the Megohms I needed to measure. I
managed to get the range up to 250 Kilohms by careful
capacitor selection, but the impedance of the
Microcontroller pins wouldn't allow me to go any higher than
that. I solved this problem by designing a parallel plate
sensor with an area of 200 square centimeters and a distance
between plates of one centimeter. This converted a bulk
resistivity of 18 Megohms per cubic centimeter to a
resistance of 90 Kilohms - well within the capability of the
Microcontroller. I used the same Microcontroller to measure
a thermistor to detect the water temperature and wrote a
calibration table in software to compensate for temperature
and sensor nonlinearity. The Microcontroller had limited
memory, so I wrote the table with 11 temperature values from
0 degrees C to 100 degrees C in 10 degree steps and 21
resistivity values from 0 ohms to 20 Megohms in 1 Megohm
steps. From these values, I extrapolated 1 degree and 0.1
Megohm steps, which were displayed on the LCD. The same
sensor also served as a water level detector; when the tank
level got too low, there was air between the plates instead
of water and the open sensor reading would trigger the
addition of more ultra-pure water. I wrote code so that if
the water stayed on for too long without filling the tank it
would give up and display an error. I used the same scheme
so that if the water stayed on for too long without
increasing the resistivity to an acceptable level, it would
give up and display an error.

"Another interesting challenge occurred when the prototype
started acting strangely. Over the course of several hours,
the bulk resistivity of the ultra-pure water as measured by
the Microcontroller would rise above the theoretical maximum
of 18 Megohms per cubic centimeter, while the commercially
available resistivity meter would show no change. Eventually
the Microcontroller software would erroneously conclude that
the water level was below the plates and would add
ultra-pure water. As soon as a small amount of additional
ultra-pure water was added, the reading would immediately go
back to normal. I found that stirring the water made the
problem go away - it only happened when the water was very
still. It turns out that the ions in the ultra-pure water
were moving away from one plate and collecting on the other
plate. I programmed the Microcontroller to swap which plate
was grounded and which plate was exited at each reading. At
this point, the sensing system tracked the commercial meter
perfectly."
 
B

Ben Bradley

Jan 1, 1970
0
In sci.chem.electrochem,
sci.chem.electrochem.battery and
sci.electronics.design,
MIME-Version: 1.0
Content-Type: Text/Plain; charset=US-ASCII


(Keeping in mind that I am an electronics engineer with quite
limited knowledge of chemistry and some experience in designing
low-cost low-performance resistivity meters...)
I am after water with an R>18[Mohm/cm]

Water over 18.2Mohm/cm@25C doesn't exist. At room temperature
it spontaneously forms H+ and OH- Ions (and H3O+ Ions?
My memory fails me on that one).

Also, at what temperature? Ultrapure changes resistivity
4.5% per degree C @25C.
Also what is the best way of storing ultra pure water

It doesn't exist. You need to purify it on the spot. Ultrapure
water will dissolve anything it possibly can, and you want to give
it as little time leaching chloride from plastics and dissolving
metals and glass as possible. Making pure water is difficult,
and keeping it that way is impossible
Should I dispense it in to several small bottles with pipette lids?

No. To stay even close to 18.2Mohm/cm@25C you must start with
vacuum degassed ultrapure water and then never let it contact
air.

O2 dissolved in the water makes it better at attacking metals
(and lowering the resistivity) and dissolved CO2 will make
carbonic acid, which then attack the metal. You will get
lots of CO2 in the water even though the air doesn't have
much because CO2 dissolves so well, and ultrapure water has
little or no buffering capacity.

I recall something about pure water in sonoluminescence. There's a
whole article on how to do sonoluminescence in the Feb. 1995
Scientific American in the "The Amateur Scientist" column (I've got
all of the "Amateur Scientist" columns on a CD that's for sale
inexpensiely on the web, I strongly recommend it for anyone with even
a mild interest in science).
The article discusses getting the air gases out of distilled water
by boiling it, then sealing the container before letting it cool.
Sonoluminescence is a neat effect in itself, and apparently no one
yet knows how the light is generated.
 
T

The Phantom

Jan 1, 1970
0
The said:
Guy Macon said:
If this doesn't frighten you enough, do a Google search
on [ oligotrophic ultrapure ].

One site (http://aem.asm.org/cgi/content/full/68/4/1548)
says "The extracellular polysaccharide matrix acts as a
diffusion barrier to nutrients and cellular products and
allows nutrients from the flowing water to reach bacterial
cells" ^^

Nutrients? What nutrients? It's just water with
"... less than 1ppb contaminants".

It doesn't seem like it, but they do grow in ultrapure water.
One kind makes a living by grabbing the manganese from any
stainless steel it finds.

But isn't it going to need something in addition to manganese (such
as carbon) to live? Where does it get the carbon? One of the sites I
looked at suggested they might get carbon from the dead carcasses of
other organisms present. But this can't go on forever can it? And
with so few of them present, what is the probability that a bacterium
that needs carbon is going to make contact with another (dead)
organism? This is all very strange.
 
G

Guy Macon

Jan 1, 1970
0
The Phantom wrote:

(Concening things that grow in ultrapure water that has nothing but
pureH20 down to the perts per billion level)
But isn't it going to need something in addition to manganese (such
as carbon) to live? Where does it get the carbon? One of the sites I
looked at suggested they might get carbon from the dead carcasses of
other organisms present. But this can't go on forever can it? And
with so few of them present, what is the probability that a bacterium
that needs carbon is going to make contact with another (dead)
organism? This is all very strange.

It is indeed. When it comes to biology I am a pretty good electrical
engineer, but I have seen with my own eyes the slime that lives on
stainless steel in ultrapure waterand I have seen the slow-growing
filaments that can grow in ultrapure water in a polypropylene container.
Life manages to find a way.
 
G

Guy Macon

Jan 1, 1970
0
WayneL said:
My latest work involves establishing my experimental parameter
space. Thus I need to remove the atmosphere and then re-introduce
it one gas/substance at a time. So flush out my chamber with
argon and run my tests contaminated with "pure water" (the combs
with several with AC and several with DC), then repeat with CO2
then N2 then O2 etc... For the Dc I will use a galvanostat/
potentiostat and for the AC I will use an impedance spectrometer.
So you can see why I need the pure water as I am trying to simulate
the effect each of the atmospheric condition has on water. Water
being the most likely vehicle of contamination for electrical
goods (not forgetting beer >:-] ).

Ah, but *pure* water is one of the *least* likely vehicles of
contamination for electrical goods. Compared to what actually
gets into electronics, it is far more corrosive, far less conductive,
and has far less buffering ability. If it has any contact with the
air, it becomes a fairly strong acid (about as good as vinegar if I
remember correctly), and it will constantly change purity (and thus
change the very characteristics you are investigating) from contact
with the electrical goods, thus ruining every experiment you do.
On another thread there was a discussion on overpotential(s).
If I have two copper electrode and I need to find the overvoltage
then won't they cancel each other out or do they add up.

I am hoping that one of the chemists reading this will give a
simplified explanation of how overpotential/overvoltage works
with two platinum or gold electrodes in ultrapure water, with
no voltage and with a DC voltage applied.
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Borek

Oops! I didn't notice that, either. Make that a heterocyclic ring.


C = N
// \
C C=
\\ /
C = N

Yeah, great, but what about all those double bonds in the neck? Is it
some kind of buckytube?

Thanks,
Rich
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>
wrote (in said:
Yeah, great, but what about all those double bonds in the neck? Is it
some kind of buckytube?

No, it's just a highly unsaturated straight-chain hydrocarbon residue.
Perhaps more common in molecular gas clouds than on Earth, but it could
be made.
 
N

Ned Forrester

Jan 1, 1970
0
|> In sci.chem.electrochem,
|> sci.chem.electrochem.battery and
|> sci.electronics.design,
|> on Wed, 05 Jan 2005 13:48:06 +0000, Guy Macon
|> <http://www.guymacon.com/> wrote:
|>
|> >MIME-Version: 1.0
|> >Content-Type: Text/Plain; charset=US-ASCII
|> >
[snip]
|> >WayneL wrote:
|> >
|> >>Also what is the best way of storing ultra pure water
|> >
[snip]
|> >>Should I dispense it in to several small bottles with pipette lids?
|> >
|> >No. To stay even close to 18.2Mohm/cm@25C you must start with
|> >vacuum degassed ultrapure water and then never let it contact
|> >air.
|> >
|> >O2 dissolved in the water makes it better at attacking metals
|> >(and lowering the resistivity) and dissolved CO2 will make
|> >carbonic acid, which then attack the metal. You will get
|> >lots of CO2 in the water even though the air doesn't have
|> >much because CO2 dissolves so well, and ultrapure water has
|> >little or no buffering capacity.
|>
|> I recall something about pure water in sonoluminescence. There's a
|> whole article on how to do sonoluminescence in the Feb. 1995
|> Scientific American in the "The Amateur Scientist" column (I've got
|> all of the "Amateur Scientist" columns on a CD that's for sale
|> inexpensiely on the web, I strongly recommend it for anyone with even
|> a mild interest in science).
|> The article discusses getting the air gases out of distilled water
|> by boiling it, then sealing the container before letting it cool.
|> Sonoluminescence is a neat effect in itself, and apparently no one
|> yet knows how the light is generated.

Last spring I helped a high school science fair student with a
sonoluminescence project that he had been trying to get going for a
couple of years; it turns out he had the right instructions, but
needed more electrical experience to implement them. The light
generated is dim, but no less awe inspiring, given the lack of
understanding about why it works.

Anyway, the instructions called for degassed water, but not pure
water. While we never tried it pure, he followed the recomendations
by using a mixture of glycerin and water. I don't know what
fractions. He degassed the sample by the boiling method after mixing
and just prior to loading the test cell.

--
NOTE: to reply, remove all punctuation from email name field

Ned Forrester [email protected] 508-289-2226
Applied Ocean Physics and Engineering Dept.
Oceanographic Systems Lab http://adcp.whoi.edu/
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
 
R

Rich Grise

Jan 1, 1970
0
I read in sci.electronics.design that Rich Grise <[email protected]>


No, it's just a highly unsaturated straight-chain hydrocarbon residue.

Sounds like a name for a new punk band. ;-)
Perhaps more common in molecular gas clouds than on Earth, but it could
be made.

Thanks!
Rich
 
B

Ben Cohn

Jan 1, 1970
0
Guy said:
The Phantom wrote:

(Concening things that grow in ultrapure water that has nothing but
pureH20 down to the perts per billion level)


It is indeed. When it comes to biology I am a pretty good electrical
engineer, but I have seen with my own eyes the slime that lives on
stainless steel in ultrapure waterand I have seen the slow-growing
filaments that can grow in ultrapure water in a polypropylene container.
Life manages to find a way.


I think it would be relevant to point out that biofilms (which, I
believe, the slimes you are referring to are) often have emergent
qualities unobserved in individual cells. Usually, they need some
obvious source of nutrients, but there could be nutrient sources we
overlook in conditions such as this.
 
I

Ianae

Jan 1, 1970
0
I think it would be relevant to point out that biofilms (which, I
believe, the slimes you are referring to are) often have emergent
qualities unobserved in individual cells. Usually, they need some
obvious source of nutrients, but there could be nutrient sources we
overlook in conditions such as this.

Yes, this is a classic biofilm, although I also have no idea what sustains it
under these conditions.
 
D

Dieter Britz

Jan 1, 1970
0
Ianae said:
Yes, this is a classic biofilm, although I also have no idea what sustains it
under these conditions.

Eating the polypropylene? Have you tried in a glass, or quartz,
container?

My "academic grandfather", Prof. Breyer (of ac polarography fame)
once told me that he had seen stuff grow in a solution of HgCl2.
Life, as you say, will find a way.
 
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