I hate imperial units

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Does kV/inch for dielectric strength drive you nuts too?

I have a problem with metric units being used exclusively in U.S. science education. The reality is we have not converted, and won't be anytime soon. It would be good to send a message to students that science applies to everyday life, but for that it helps to use everyday common units for science homework problems. At least assign a fraction of homework using feet & pounds so it's more meaningful to American students.

Mark

I have often wondered about the intransigence of Americans and Britons when it comes to SI. If an alien race invaded Earth, they would see immediately that we are a lazy race. We have spent millions on publicity campaigns to convert, and nothing has changed really.

-Le Chaud Lapin-

Are you saying Aliens ain't lazy or political....(for extra bonus points on their arrival) or are you putting yourself forward for chief negotiator?

DNA

Only those aliens who are regularly participating in Usenet newsgroups are political.

Are you trying to imply all three terms are mutually exclusive?

DNA

What about the aluminum? Doesn't the heat flow lag the temperature input?

Thanks, Rich

That became glaringly obvious to me once, when I downloaded a CAD drawing from SKF, to fit it into this thing I was detailing. Well, I just used the "import" function, and when I imported this metric file into my inch file, it showed up 25.4x size - the bearing was bigger than the whole machine!

So I scaled it by 0.03937, and it seemed to fit OK. ;-)

(A little OT for electronics, but everybody already knows I'm crazy, so probably no harm done.) ;-)

Cheers! Rich

Well, the "imperial" units are just plain more natural. Your thumb is an inch (albeit, your little finger is a cm), and one foot is one foot! ;-) And from outstreched fingertip to fingertip is 1 fathom, or 2 yards. ;-)

Cheers! Rich

You should worry....... I might have learnt recently that 25.4mm is not an exact inch.

However I suppose that with mechanical stuff things will bed themselves in or you use the right grease with additives for the slopp.

DNA

To be honest, that is one (more) thing about the U.S. of A. that surprises me. While you have over the centuries appeared more than eager to throw off the vestiges of your anglo antecedents, you cling to their antiquated weights and measures system (incorporating some aberrations like gallons).

I grew up in the imperial system, faced conversion to metric-cgs in the early

If the US is determined (has determined?) not to change to SI units "any time soon", then certainly exposure to both systems is a must.

Hello Speff,

You can eliminate most of the work and errors by using an equation solver. Just enter the unit conversions, then solve for the desired parameter.

This method is very fast and gives high confidence in the accuracy of the results. I have tried different equations solvers but found Roger Schafly's Mercury to be the best for this work.

Here's a simple example. Say we need to find out how many barleycorns there are in pi furlongs.

Start by entering the unit conversions. (Note there is no direct conversion between barleycorn and furlong.)

; Unit Conversion Factors

foot = yard * 3 furlong = yard / 202 inch = barleycorn / 3 inch = foot * 12 yard = fathom * 2

Now enter the desired parameter(s):

; Parameters

furlong = pi

The solution is:

barleycorn = 68536.985330715 fathom = 317.300858012569 foot = 1903.8051480754 furlong = 3.14159265358979 inch = 22845.6617769050 yard = 634.601716025138

(I simplified the printout to make it more readable.)

Now you can solve for any unknown. Just enter the desired parameter and press solve. Unlike ordinary algebra solvers, you don't have to rearrange the equation to put the unknown on the left side. This is where many of the errors occur.

Once you have entered the necessary unit conversions, you don't have to touch them again. This saves time and eliminates errors, since you are re-using conversions that have already been debugged. You can simply cut and paste from other files to add more units whenever needed. Pretty soon you will have a library of conversions you can draw on that will simplify and speed your work.

Roger Schafly's Mercury is free and available at

Hope this helps.

Regards,

Mike Monett

Antiviral, Antibacterial Silver Solution:

Just to minimize confusion, Mercury is at

Roger also gives you an updated version of Eureka, which is the predecessor to Mercury. That link is

In most cases, either program can be used. It is good to have both programs in the rare event when a file will run on one but not the other. Regards,

Mike Monett

Antiviral, Antibacterial Silver Solution:

as

equations,

even

Of course not. Aluminum is a resistor/capacitor/low-pass filter like any other material. A thermal inductor would have the temperature lead the heat; rather a silly idea.

Hmm, I simply cut the molding back and don't sweat the silly=20 millimeters. That's what molding is for!

My boiler is 125K BTU/hr, so I can easily scale from there. ;-)

--=20 Keith

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e=20

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I did that for my bathrooms. It really doesn't take that long. =20 FOr the master bathroom I wanted to make sure the backer-board=20 didn't line up on either the subfloor joints or the floor joists. =20 I laid them all out in A9CAD, then laid the room outline on that. =20 It was a simple matter to lay the tile grid on that to find the=20 optimum starting point, which wasn't where I first expected. I had=20 nearly full tiles on three sides ("1/2 off two edges and those=20 under the base molding). Full tiles against the tub looked great,=20 since there "edge" on the tile. =20 =20

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Amazingly my house is perfectly square (just had it measured for=20 carpeting and was surprised how close he had to measure). THere is=20 one wall that is embarrassingly out of plumb though.

Sharpies or wax pencils work. They do tend to wash off the glazed=20 surfaces though. I'm normally done cutting by then.

Fortunately I'm done tiling in this house. I just finished the=20 mantle (really a 3" thick concrete and marble tile slab) over the=20 wood stove. Gotta pack away the wet saw and the tools...

--=20 Keith

...for times long compared with the 2/3 power of the mass in grams.

That is neat, you're right.

Cheers,

Phil Hobbs

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equations,

even

Yep, no thermal inductors because the heat equation is first order in time, so there are no imaginary exponential solutions.

Cheers,

Phil Hobbs

Wow, never met one of those. But I do know some mechanical engineers who seem surprisingly lifelike.*

Cheers,

Phil Hobbs

(*) and some software engineers who are usually paged out to disc.

as

That's a capacitor, at least if temperature is voltage and heat flow is current. Anyhow, there are no dual reactances, so thermal systems don't oscillate, ring, or overshoot.

John

That discrepancy was repealed in 1964.

Bye. Jasen