Whats the most unique engineering unit you've encountered? 5

[JGard1985]

For fun, what is the most unique engineering unit you've encountered in your years?

Some considerations:
[ul]
[li]Name[/li]
[li]Units that mixing and matching english and metric[/li]
[li]Usefulness & practicality[/li]
[/ul]

My two first nominations:
[ul]
[li]KW/foot: A mix & match of english & metric, its used in the commercial nuclear power industry. The unit is a of measure of the amount of energy produced in metric, per linear foot of fuel rod. The calculation is important for evaluating the heat transfer capacity to the water in the reactor. Too much energy will result in fuel clad damage, compromising the integrity of the first fission barrier [/li]
[li]slinch: The slinch is an english unit of mass equal to 1 lbf*sec^2/in. (Think Weight divided by 386.6in/sec^2) In my opinion it has almost no practical application except for use in the mass input for english-unit based Finite Element Models.[/li]
[/ul]

Excited to hear your nominees

Jeff
Pipe Stress Analysis
Finite Element Analysis

http://www.xceed-eng.com

 

[Sparweb]

waross,
Perhaps you could be the hero and clear up the "issues" with this Wikipedia page:

https://en.wikipedia.org/wiki/Four-valued_logic

STF

 

[waross]

Wrong page;

https://en.wikipedia.org/wiki/Three-valued_logic[/URL]]In logic, a three-valued logic (also trinary logic, trivalent, ternary, or trilean[1], sometimes abbreviated 3VL) is any of several many-valued logic systems in which there are three truth values indicating true, false and some indeterminate third value.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Sparweb]

Well that one's got unsourced citations, too. Get to work!

The truth-tables you get from 3VL are really unbalanced. (a)OR(b) gives only 1 false result, 3 uncertain results, and 5 True results!
They lost me when they created the new expression (a)IMPLIES(b)...

STF

 

[waross]

The point of my lesson was to emphasize the importance of including a system reset when the circuit was initially powered up.
The reset would ensure that the system was now a two state system.
It is quite easy to design a dependable circuit to disable all outputs until the initial system reset, without involving the third state.
Thanks for the references. I enjoyed reading them.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[IRstuff]

We had a co-worker who read about ternary logic back in 1986-ish, and immediately began extolling its virtues and pushing the buzzwords around; EVERYONE but her recognized that 3-valued logic in a binary world was going to be a hard sell and hard do.

When she decided to go to a greener pasture, we had a great going away party, but somehow neglected to tell her about it; oops... ;-)

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[HamburgerHelper]

I can't find the article but I think there was a computer put together in year that had intentional errors in its calculations. A wrong close fast answer is better than a slow exact answer, I think the idea was.

 

[IRstuff]

Actually, there are a couple of instances where noise (error) is a good thing. In certain A/D operations, some added noise allows the digitization to have more variance, which can make it easier to get a more accurate answer after averaging. In some other cases, added noise allows digital filters to break out of limit cycle mode.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[waross]

Remember BCD? Each digit used only 10 of 16 possible counts for a waste of 6/16 or 37.5% waste. Still it had a lot of application interfacing with legacy 10 based counting devices.
Binary counting in ternary logic (There is not a great volume of base 3 legacy counting devices.) may reduce the wasted resource to only 1/3 or 33%.
But all things considered, I'd rather discuss the Smoot. Does anyone know how many "ears" there are in a smoot?


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dik]

I haven't heard of Binary Coded Decimal in 30 years...

Dik

 

[waross]

Now that you mention it I haven't said Binary Coded Decimal for over 30 years. Do you remember the "Switch Tail Ring Counter"?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dik]

Just vaguely... was helping one of my programming buddies with some timing diagrams for them, if memory serves... Used to be heavy into programming (a hobby) and often worked at the hardware level... I'm the only fool that hardwired an 8088, way back... about 30,000 solder connections...

Dik

 

[Sparweb]

I just ran across a strange unit here:

http://www.endurasim.com.au/wp-content/uploads/2015/02/EnDuraSim-Engineering-Units.pdf

They introduce the "snail".
It comes as a result of the definition of a pound being partly based on the foot, but engineering measurements usually expressed in inches. Hence, they include a 12 pound unit that they call the snail.
Then they convert it to slugs.

STF

 

[dik]

Slug = weight in lbs / g sort of reminds me of an erg or a dyne (not sure which, haven't used them in 50 years), but in SI, a force/g

Dik

 

[VEBill]

A YouTube star going by the handle 'AVE' (most of you would enjoy his cheeky and instructional videos) offers a ruler with "...the popular 'C.H.' scale...".

Explanation:

https://www.etsy.com/listing/464202928/one-rule-to-ruler-them-all-cheeky-jokes

2nd image, Zoom, extreme right hand end of ruler.

 

[drawoh]

dik,

A slug is weight in pounds divided by gravitational acceleration in feet per second squared. The thing I like about doing calculations in English units is that I can avoid derived units like Newtons and slugs. As far as I am concerned, g=386in/sec[sup]2[/sup]. I replace m with w/g. Using the metric system, I consider it absolutely critical to stick with the SI MKS[ ]units. Otherwise, weird things can happen.

--
JHG

 

[dik]

drawoh:

Yup... g=32.2... ft/sec2

Dik

 

[JohnRBaker]

2nd image, Zoom, extreme right hand end of ruler.

Not exactly what you'd call politically correct, eh?

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[concretemasonry]

"Instrument set-ups per day" was my favorite.

I attended a school(Univ of MN) with a 5 year civil engineering curriculum. It was 250 credit course that included a 3 credit summer surveying class plus a 4 week field class at a school 180 miles away. It involved lake sounding and the usual land, highway and railroad surveying with different instruments - transits, levels, theodolites and electronic distance measuring. It got tiring setting up the equipment, so we decided to come up with a way to measure what we went through and used the set-ups concept of a measure of work of effort that day.

The second choice was the "drops per day" for the dropping and retrieving the depth sounding weights, while the other students got to measure the angles with transits to the boat from location to create a map via triangulation using flags as a signal when the depth weights were dropped. (pretty archaic)

After graduation, I did get to use surveying a couple of times in the aerospace industry.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[dik]

...like a BFR... a rock too big to step over, but, not big enough to warrant walking around...

Dik

 

[77JQX]

How about the "miner's inch"? Defined differently in different jurisdictions, it is the water flow through a 1 square inch opening with a specified head (say 6 inches of water).