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You all know how the song goes:
I'm a real guy, I like real guy things
Like boats, and guns, and onion rings,
But household chores need a power resolution.
I went to the store and I purchased a solution...
...I got a pressure washer.
I like it a lot
Cos it makes cleaning DESTRUCTIVE!
Well, last night I went to a shop, and bought... an infrared remote
thermometer, and an environment meter that measures light, sound and
heat. Now I can find out the temparature of EVERYTHING!! Muhuhuhu!!!
Actually, the light readings are gibberish, and the temparature readings
seem rather suspect. The sound readings seem reasonable though.
A number of people have complained about how loud of lab is. So I
thought I'd find out how loud it *really* is!
Obviously, the first problem is trying to define "loud". According to
the infallible Wikipedia, there are four standardised frequency responce
curves commonly used. Apparently the "A" curve was designed for quiet
sounds and is really rather invalid for loud sounds - and yet, almost
all legal constructs operate on A-weighted readings. Ho hum! Apparently
the "C" curve is a much better one to use.
In some unscientific experiments today, I've found that the readings
from the metal really don't change very much depending on what I
percieve the loudness to be. (OTOH, dB is a *logarithmic* scale...)
Depending on whether I select A-weighted or C-weighted filtering, I get
a figure between 60 dB and 85 dB. Various Google searches indicate that
long-term exposure to levels around 85 dB or higher result in hearing
damage. (But infuriatingly NONE of the articles say WHICH WEIGHTING
that's with, so it's kind of meaningless.)
At any rate, you can argue over different frequency response curves to
use and what is or isn't harmful. But it seems that you can probably
conclude that the noise levels in our lab are high enough to be of
concern, even if you can't conclusively say they are or aren't safe.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> the temparature readings seem rather suspect.
Those IR thermometers work by assuming the object you're pointing at has a
specific emissivity (which is hard-wired in on cheap models), and also a
certain temperature of environmental radiation. Unless you set those two
accurately for each thing you measure you'll never get an accurate
temperature reading using IR.
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scott wrote:
>> the temparature readings seem rather suspect.
>
> Those IR thermometers work by assuming the object you're pointing at has
> a specific emissivity (which is hard-wired in on cheap models), and also
> a certain temperature of environmental radiation. Unless you set those
> two accurately for each thing you measure you'll never get an accurate
> temperature reading using IR.
I actually meant the readings from the *other* thermometer is rather
suspect. The readings from the IR thermometer agree with our validated
instrument.
(And yes, it's hard-wired to 0.95 thermal emissivity. Apparently it's
supposed to compensate for air temparature. And it won't work on "shiny"
surfaces. And also takes a moment or two to go from very hot to very
cold things...)
The environment meter has a temparature/humidity wand, and it dissagrees
with our validated thermometer by several degrees above or below. It
also seems to take a VERY long time for the reading to change.
On the other hand, the metal temparature probe that comes with it seems
more reliable. I haven't compared it to the validated instrument, but it
does at least seem to more or less instantly change reading when you
heat or cool it.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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scott wrote:
> Those IR thermometers work by assuming the object you're pointing at has
> a specific emissivity (which is hard-wired in on cheap models), and also
> a certain temperature of environmental radiation. Unless you set those
> two accurately for each thing you measure you'll never get an accurate
> temperature reading using IR.
Of course, what I *really* wanted is one of those thermal imaging
cameras which visually show you how hot things are... but I have no idea
where the hell you can buy those. :-(
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> Of course, what I *really* wanted is one of those thermal imaging
> cameras which visually show you how hot things are... but I have no idea
> where the hell you can buy those. :-(
We got ours from these guys:
www.flirthermography.co.uk
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scott wrote:
>> Of course, what I *really* wanted is one of those thermal imaging
>> cameras which visually show you how hot things are... but I have no
>> idea where the hell you can buy those. :-(
>
> We got ours from these guys:
>
> www.flirthermography.co.uk
Oooo.... I forsee this becoming a VERY expensive week! :-D
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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"Invisible" <voi### [at] dev null> wrote in message
news:48451ea7$1@news.povray.org...
> You all know how the song goes:
Nope.
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Invisible wrote:
> Actually, the light readings are gibberish, and the temparature readings
> seem rather suspect. The sound readings seem reasonable though.
N00BULATION!!!
The instruction manual fails to mention this, but if you look at the
light sensor there are two small slits in the side. If you grib these
and pull, THE LID COMES OFF, revealing a transparent window into the
light sensor chamer. If you do this, oddly enough the sensor now detects
light.
What.
The.
Hell.
HOW can the manual completely fail to mention that the top surface of
the pod is removable? There aren't even any markings on it. You're just
supposed to *guess* that the two tiny slits in the side are so you can
grip it to remove the lid.
I spent 10 minutes getting the shop assistent to look at it before one
of the other staff came over and pointed out that the pod actually has a
removable lid. Me and the first guy just looked at each other like "Oh
my GOD, we are really this stupid?"
I LOLd. Hard. Almost as hard as the two chav kids stood next to me.
Frickin' n00bulation FTW! :-S
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Invisible wrote:
> N00BULATION!!!
I have a manual for a clock. In the back is the troubleshooting chart.
Q: No numbers appear on display.
A: Insert fresh battery.
Q: Numbers appear on display even without battery.
A: Take sticker off of display.
--
Darren New / San Diego, CA, USA (PST)
"That's pretty. Where's that?"
"It's the Age of Channelwood."
"We should go there on vacation some time."
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Darren New wrote:
>
> I have a manual for a clock. In the back is the troubleshooting chart.
>
> Q: No numbers appear on display.
> A: Insert fresh battery.
>
> Q: Numbers appear on display even without battery.
> A: Take sticker off of display.
>
:-)
--
I will be brief but not nearly so brief as Salvador Dali, who gave the
world's shortest speech. He said, "I will be so brief I am already
finished," then he sat down.
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Darren New wrote:
> Q: Numbers appear on display even without battery.
> A: Take sticker off of display.
You *know* this question came up in end-user testing! ;-)
[My manual appears to have been machine-translated form some other
language, judging by the strange sentence constructions...]
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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In case anybody else out there is as obsessive as me...
http://blog.orphi.me.uk/archives/312
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> In case anybody else out there is as obsessive as me...
>
> http://blog.orphi.me.uk/archives/312
...or in tabular form...
http://blog.orphi.me.uk/about/temperatures
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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>> In case anybody else out there is as obsessive as me...
>>
>> http://blog.orphi.me.uk/archives/312
>
> ...or in tabular form...
>
> http://blog.orphi.me.uk/about/temperatures
Things that look shiny are often shiny to IR too (eg your gloss black oven
top, car paintwork, etc) - so you're going to be measuring the temperature
of whatever is being reflected more than the actual thing.
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"Orchid XP v8" <voi### [at] devnull> a écrit dans le message de news:
4846e669$1@news.povray.org...
> In case anybody else out there is as obsessive as me...
>
> http://blog.orphi.me.uk/archives/312
>
Must we understand that you drop your choppen chicken in a COLD frying pan?
Marc
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scott wrote:
> Things that look shiny are often shiny to IR too (eg your gloss black
> oven top, car paintwork, etc) - so you're going to be measuring the
> temperature of whatever is being reflected more than the actual thing.
In the case of the car, that's going to be the sky (surely not that warm
on a cloudy day?) or the wall (presumably at equillibrium with the
surroundings). And yet, I got a fairly warm reading.
In the case of the cooker, that ought to be the gas flames. [Now there's
a question - can an IR thermometer measure the temperature of a flame?
Or will it measure the next solid object behind it?] Or, alternatively,
the underside of the flying pan. Either way, the temperature I measured
seemed pretty low.
If you wanted to be technical, presumably the IR arriving at the sensor
is the SUM of reflected and emitted? (What the computer calculates the
temperature at is another matter of course...)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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m_a_r_c wrote:
> Must we understand that you drop your choppen chicken in a COLD frying pan?
For the purposes of Science, you understand. ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> In the case of the car, that's going to be the sky (surely not that warm
> on a cloudy day?) or the wall (presumably at equillibrium with the
> surroundings). And yet, I got a fairly warm reading.
The objects are not 100% reflecting though, what I meant was your reading is
going to be lower than you expected because of the reflection.
> In the case of the cooker, that ought to be the gas flames. [Now there's a
> question - can an IR thermometer measure the temperature of a flame? Or
> will it measure the next solid object behind it?]
It works the same way as visible light. Can you see the next solid object
behind a flame? It depends how bright the flame is and how bright the
object is behind.
> If you wanted to be technical, presumably the IR arriving at the sensor is
> the SUM of reflected and emitted? (What the computer calculates the
> temperature at is another matter of course...)
The computer assumes the following equation, where e is the emissivity:
sensorReadingIR = emittedIR * e + reflectedIR * (1-e)
Rearranged:
emittedIR = ( sensorReadingIR - reflectedIR * (1-e) ) / e
It calculates reflectedIR from the "environment temperature" you program in
to it. You also tell it e, and of course it knows the sensorReadingIR. It
then calculates the temperature of the surface from emittedIR.
As you can imagine, if you program e to be 0.9, but you're actually
measuring something with a lower e, the computer is going to get the
calculation wrong and tell you it's at a lower temperature than it actually
is (assuming the object is hotter than the environment).
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"Invisible" <voi### [at] devnull> a écrit dans le message de news:
4847cbc6$1@news.povray.org...
> m_a_r_c wrote:
>
>> Must we understand that you drop your choppen chicken in a COLD frying
>> pan?
>
> For the purposes of Science, you understand. ;-)
Oh well You're forgiven, then :-)
You can't expect Maillard's reactions with meat bathing in it's own juice :
Maillard reactions don't like moisture.
http://en.wikipedia.org/wiki/Maillard_reaction
That's why chiefs get food browned before proceeding to deglazing and obtain
an excellent 'jus'.
BTW I think you'd get hotter pan cooking 'plateau' temperature by dropping
the meat in yet hot pan because less water would be boiling at a time.
Marc
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