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  #31  
Old February 28th 18, 06:34 AM posted to rec.bicycles.tech
ERSHC
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Posts: 32
Default rubber compounds

On Tue, 27 Feb 2018 16:35:21 -0500, Frank Krygowski wrote:
On 2/27/2018 1:01 PM, Jeff Liebermann wrote:
The wet/dry bulb (psychrometer) was invented in the
early 19th century. That morphed into the sling psychrometer:
https://www.google.com/search?q=sling+psychrometer&tbm=isch
which earned me an afternoon at the local police station while they
attempted to identify the type of weapon I was swinging around.


I'm betting you and I are the only ones here who have used a sling
psychrometer.


Sorry, but you loose. I think just about everyone in 7th grade Science
(IIRC, it was a while ago) in my school did this.

I never got arrested for doing it, though.

(I can't even remember where my psychrometric chart is now.)

Try page E-39 of the 53d edition (1972-73) of the Rubber Bible.
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  #32  
Old February 28th 18, 05:04 PM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default rubber compounds

On Tue, 27 Feb 2018 21:39:18 +0100, Emanuel Berg
wrote:

Jeff Liebermann wrote:

Capt Nemo probably had one aboard the
Nautilus as too much or too little humidity
in a closed environment tends to do bad
things to men and machines.


What humidity is that?


If you are living in a closed environment, with no access to
recirculated air, the humidity from everyone's breath and sweat tends
to accumulate. Eventually, it gets high enough to be seriously
uncomfortable (if the CO2 buildup doesn't kill you first). It's like
that in any artificial atmosphere environment, such as space capsules,
submarines, and well insulated houses. Humidity is a bit part of
feeling comfortable:
https://en.wikipedia.org/wiki/Thermal_comfort#Relative_humidity

Here in the
studio/office right now is 18.3C/22% and in the
workshop is -3.6C/56%. With a heat fan, I can
get that up to ~4.5C tho. Outside is -11C and
a heat fan won't help

But I don't need data to know that -3.6C is too
cold to work with tools, one needs to go inside
in between every individual part just a second
to get back warm hands.


I'm not sure what point you're trying to make here. RH is the ratio
of the amount of water in the air divided by the amount of water it
could hold. When the temperature drops, the air can hold less and
less water. If you lived in a cold Aortic region, the RH is very low
making it as dry as a desert. That's also why you can defrost the
inside of your automobile windshield by turn on the air conditioner.
Air conditioned air is quite dry.

Where an accurate psychrometer comes in handy
is demonstrating to buyers of elaborate
electronic weather stations that their
humidity measurements are very slow to
change, and rather inaccurate.


I tested my analogous German-made hygrometer
after a hot shower, but not in the actual
shower of course, and it had changed a lot.
So how slow is "slow"?


I don't have time for an elaborate answer right now. Search for
"humidity sensor response time". You'll find that the common
capacitance sensor found in home wx stations varies from about 1
minute (for a large change in humidity) to several days for an initial
power on (due to lousy air circulation).

This article says:
https://www.sensorsmag.com/components/choosing-a-humidity-sensor-a-review-three-technologies
"The response time for most resistive sensors ranges from
10 to 30 s for a 63% step change."
My experience is more like several hours for capacitance sensors. I'll
see if I can find the data sheets on some of the sensors in my
collection later today.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #33  
Old February 28th 18, 05:28 PM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default rubber compounds

On Tue, 27 Feb 2018 16:35:21 -0500, Frank Krygowski
wrote:

On 2/27/2018 1:01 PM, Jeff Liebermann wrote:
The wet/dry bulb (psychrometer) was invented in the
early 19th century. That morphed into the sling psychrometer:
https://www.google.com/search?q=sling+psychrometer&tbm=isch
which earned me an afternoon at the local police station while they
attempted to identify the type of weapon I was swinging around.


I'm betting you and I are the only ones here who have used a sling
psychrometer.


They're common enough in the skools. The big problem is that they
break easily and make a mess. I vaguely recall that there were
several in the "lab", all with at least one thermometer broken. So, I
built my own and made the mistake of trying it on the skool bus. The
driver didn't know what it was, decided it was a weapon of some sort,
and called the police, who were waiting when I arrived at skool.

I never got arrested for doing it, though.


I wasn't arrested, but rather detained for investigation. My father
had to leave the factory early to rescue me. I expected dire
consequences or worse. However, all he did was chuckle and suggest
that I not perform science experiments on the skool bus.

(I can't even remember where my psychrometric chart is now.)


They're commonly online. I use the programs and apps on my computah
and smartphone. The problem with tables is that they don't include
the effect of atmospheric pressure. For charts, search for C.F.
Marvin tables.
https://www.google.com/search?q=c.f.+marvin+relative+humidity+tables

There's also calibration:
https://www.allaboutcircuits.com/projects/how-to-check-and-calibrate-a-humidity-sensor/
If you graph the humidity, as measured with a psychrometer, versus the
indicated humidity from a capacitive sensor, you'll find about 5%
hysteresis. In order to get accurate numbers, I sometimes have to
compensate for the effect and others.



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #34  
Old February 28th 18, 05:50 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 1,035
Default rubber compounds

Jeff Liebermann wrote:

It's like that in any artificial atmosphere
environment, such as space capsules,
submarines, and well insulated houses.


OK, then I'm safe as this building is poorly
insulated everywhere and in spots not insulated
at all. The room where I am right now is the
best insulated place. Still I have three
power oil radiators yet temperature is only
18.0C/22% with -8C outside.

--
underground experts united
http://user.it.uu.se/~embe8573
  #35  
Old March 1st 18, 12:13 AM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 4,018
Default rubber compounds

On Wed, 28 Feb 2018 17:50:00 +0100, Emanuel Berg
wrote:

Jeff Liebermann wrote:

It's like that in any artificial atmosphere
environment, such as space capsules,
submarines, and well insulated houses.


OK, then I'm safe as this building is poorly
insulated everywhere and in spots not insulated
at all.


Sorry, bad choice of words. Instead of insulated, I should have said
ventilated. A really well insulated house should not have any air
leaks, where cold air from the outside can leak in, and warm air from
the inside leak out.

The room where I am right now is the
best insulated place. Still I have three
power oil radiators yet temperature is only
18.0C/22% with -8C outside.


26C temperature differential between outside and inside. Yeah, that's
quite good insulation, depending on how much energy you're putting
into heating the room. My house is a "summer vacation home" which
leaks badly and is poorly insulated. Air leaks everywhere, no
insulation in the floor, ceiling or roof. Typical is 10C differential
with the wood burner setup for best efficiency and 20C when I have it
running like a blast furnace. I considered improving the insulation
and leakage situation, but it's cheaper to just burn more firewood.



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #36  
Old March 1st 18, 12:22 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,538
Default rubber compounds

On 2/28/2018 6:13 PM, Jeff Liebermann wrote:
On Wed, 28 Feb 2018 17:50:00 +0100, Emanuel Berg
wrote:

Jeff Liebermann wrote:

It's like that in any artificial atmosphere
environment, such as space capsules,
submarines, and well insulated houses.


OK, then I'm safe as this building is poorly
insulated everywhere and in spots not insulated
at all.


Sorry, bad choice of words. Instead of insulated, I should have said
ventilated. A really well insulated house should not have any air
leaks, where cold air from the outside can leak in, and warm air from
the inside leak out.

The room where I am right now is the
best insulated place. Still I have three
power oil radiators yet temperature is only
18.0C/22% with -8C outside.


26C temperature differential between outside and inside. Yeah, that's
quite good insulation, depending on how much energy you're putting
into heating the room. My house is a "summer vacation home" which
leaks badly and is poorly insulated. Air leaks everywhere, no
insulation in the floor, ceiling or roof. Typical is 10C differential
with the wood burner setup for best efficiency and 20C when I have it
running like a blast furnace. I considered improving the insulation
and leakage situation, but it's cheaper to just burn more firewood.


I used the opposite strategy. When we moved into this house, decades
ago, I was sure it was inefficient. I immediately invested lots of time
and a fair amount of money in sealing against infiltration and adding
insulation. I graphed our natural gas usage for years and was very
pleased to see the curve descend markedly.

About eight years ago, we did a small addition to the house, and
switched from the ancient primitive gas furnace to a high efficiency
model. Our gas use is now about 1/3 of what it was when we started. I
think the weatherproofing was the best investment I could have made.

We do have a fireplace, but it too was terribly inefficient, as almost
all are. Not long after we moved in I added glass doors, an outside air
intake, a blower grate, etc. That changed the fireplace from ineffective
to capable of driving us out of the room. The living room can get up to
80 degrees Fahrenheit with a big fire. But we rarely burn wood these
days. I'm not fond of slogging outside to carry the stuff in.

--
- Frank Krygowski
  #37  
Old March 1st 18, 12:59 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default rubber compounds

Jeff Liebermann wrote:

26C temperature differential between outside
and inside. Yeah, that's quite good
insulation, depending on how much energy
you're putting into heating the room.


Well, it sure doesn't feel warm and everything
I touch is/feels cold. Now its 17.5C/22% with
-9C outside.

I have two oil filled radiators that are 1500W
by the windows, and one 525W under the bed.

--
underground experts united
http://user.it.uu.se/~embe8573
  #38  
Old March 1st 18, 01:40 AM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 13,447
Default rubber compounds

On 2/28/2018 5:59 PM, Emanuel Berg wrote:
Jeff Liebermann wrote:

26C temperature differential between outside
and inside. Yeah, that's quite good
insulation, depending on how much energy
you're putting into heating the room.


Well, it sure doesn't feel warm and everything
I touch is/feels cold. Now its 17.5C/22% with
-9C outside.

I have two oil filled radiators that are 1500W
by the windows, and one 525W under the bed.


an electric heater like this?

https://www.ebay.com/itm/700W-Portab...YAAOSwYeRZ5bZd

That's it? And your building has an OP issued??


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #39  
Old March 1st 18, 03:12 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default rubber compounds

AMuzi wrote:

an electric heater like this?

https://www.ebay.com/itm/700W-Portab...YAAOSwYeRZ5bZd


Yes.

That's it? And your building has an OP
issued??


OP = "occupancy permit"? Then no

--
underground experts united
http://user.it.uu.se/~embe8573
  #40  
Old March 1st 18, 03:25 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 5,697
Default rubber compounds

On Wed, 28 Feb 2018 18:22:40 -0500, Frank Krygowski
wrote:

On 2/28/2018 6:13 PM, Jeff Liebermann wrote:
On Wed, 28 Feb 2018 17:50:00 +0100, Emanuel Berg
wrote:

Jeff Liebermann wrote:

It's like that in any artificial atmosphere
environment, such as space capsules,
submarines, and well insulated houses.

OK, then I'm safe as this building is poorly
insulated everywhere and in spots not insulated
at all.


Sorry, bad choice of words. Instead of insulated, I should have said
ventilated. A really well insulated house should not have any air
leaks, where cold air from the outside can leak in, and warm air from
the inside leak out.

The room where I am right now is the
best insulated place. Still I have three
power oil radiators yet temperature is only
18.0C/22% with -8C outside.


26C temperature differential between outside and inside. Yeah, that's
quite good insulation, depending on how much energy you're putting
into heating the room. My house is a "summer vacation home" which
leaks badly and is poorly insulated. Air leaks everywhere, no
insulation in the floor, ceiling or roof. Typical is 10C differential
with the wood burner setup for best efficiency and 20C when I have it
running like a blast furnace. I considered improving the insulation
and leakage situation, but it's cheaper to just burn more firewood.


I used the opposite strategy. When we moved into this house, decades
ago, I was sure it was inefficient. I immediately invested lots of time
and a fair amount of money in sealing against infiltration and adding
insulation. I graphed our natural gas usage for years and was very
pleased to see the curve descend markedly.

About eight years ago, we did a small addition to the house, and
switched from the ancient primitive gas furnace to a high efficiency
model. Our gas use is now about 1/3 of what it was when we started. I
think the weatherproofing was the best investment I could have made.

We do have a fireplace, but it too was terribly inefficient, as almost
all are. Not long after we moved in I added glass doors, an outside air
intake, a blower grate, etc. That changed the fireplace from ineffective
to capable of driving us out of the room. The living room can get up to
80 degrees Fahrenheit with a big fire. But we rarely burn wood these
days. I'm not fond of slogging outside to carry the stuff in.


Someone once write that a fireplace is a very good source of heat as
it warms one twice. Once when you chop the wood for the fireplace and
once more when you burn the wood :-)
--
Cheers,

John B.

 




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