Driver to drive?

[Jon Kirwan]

On Mon, 11 May 2009 08:15:23 -0700 (PDT), bill.sloman@ieee.org wrote:

On May 11, 12:27 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
Andrew wrote:
bill.slo...@ieee.org> wrote
Eeyore wrote:
In 30 years, the largest figure according to your choice of smoothing
etc and data source is about 0.2C.

http://wattsupwiththat.com/2009/05/07/april-global-temperature-anomal...

Graham

-So what? You keep on getting excited about short term noise, as if it
-said anything about the long term trend generated by the build up in
-C02 in the atmosphere.

The whole AGW hypothesis is based on short term data.

The Vostock ice-core data goes back some half a million years, but
since you don't see its relevance to AGW you probably aren't aware of
this.

Epica Dome C goes back another 300kyr, as well.

http://www.ncdc.noaa.gov/paleo/icecore/antarctica/domec/domec_epica_data.html

Other linked sources for paleoclimatology are also found nearby on
that site:

http://www.ncdc.noaa.gov/paleo/education.html

Jon

 

[Alan W]

On 5/10/2009 12:06 PM, Tim Williams wrote:

Question the first: where to find transformer (or inductor) cores?
Mouser and Digikey don't sell them plain. Who's the magnetic
equivalent of Digikey?

Other question: how to select cores? Specifically, I'm looking for
something in the 10kHz (square wave, PWM), 10kVA range, with high
permeability to minimize the number of turns. Saturation should be
fairly high, given the low operating frequency. Ratio 4:1, with about
200Vrms (fundamental component) primary and 50Vrms secondary. The
secondary will be copper tubing, 1/4 or 3/8" dia., so a one-turn
secondary is advantageous.

Given the permeability and saturation, I'm thinking something like
Metglas. I know I need something in the 2-3" range, and I can
calculate things like A_L and A*t(sat) from the properties, but it
would be a whole lot easier if I had both parameters laid out in a
table of standard shapes. I can't really make any estimates on what
size I need if I don't have a standard formula for the geometry, so I
don't even know what inductance and magnetizing current and saturation
I have to look for.

And why do they never specify amp-turns saturation? It's always in
B. I can measure amp turns, I can't measure Teslas. They give A_L by
the core, but not saturation, what the hell?

Tim

You might be able to use the free inductor design software package from
the Micrometals website. All you have to do is enter the circuit
parameters, and it calculates all the magnetic values and gives a list
of usable cores. Naturally, it only lists their own cores, but at least
it's a start. I used it a while back to design a 2KW PFC inductor, and
it saved me from having to figure out everything by hand:

http://www.micrometals.com/software_index.html

I think you can get similar software from most of the major core mfrs,
such as Magnetics Inc and maybe some others.

- Alan

 

[Richard the Dreaded Liber]

On Mon, 11 May 2009 08:08:56 -0700, John Larkin wrote:

Humans have proven to be remarkably inept and fragile in space. If a
fraction of the manned-spaceflight bucks had been spent on robotics
and science, we'd have something to show for all that lost money and
all those lost lives. Some really talented people have died in the
name of sci-fi show-biz.

OK, you think people shouldn't go to space.

But, are you talking about forcibly preventing those who _want_ to go,
from going? I wouldn't want to see that being done. It'd be like stopping
someone who wants to row across the Pacific in a kayak - it's nuts, but he
has a right to do it.

HOWEVER, the way things are now, I'd say that you have a legitimate gripe
here - you have a creator-given right to control where your money is spent
- with that, I agree 100%; but I also say, fund it with private money and
let them do whatever they want!

But don't take your money against your will and line the pockets of a
bunch of thieving politicians and bureaucrats.

Profound Revelation: The Internet has rendered Government irrelevant;
they just haven't figured it out yet.

You may quote me on that, with proper attribution, of course.

Cheers!
Rich

 

[Rich Grise]

On Mon, 11 May 2009 05:48:10 +0000, James Arthur wrote:

John Larkin wrote:

Why do we want to put humans back on the moon?

For the cheese?

"Well, it's like no cheese _I've_ ever tasted!" -- Wallace,
http://www.imdb.com/title/tt0104361/

If you haven't seen it, rent it or download it. It's awesome! 8-}

Cheers!
Rich

 

[Richard the Dreaded Liber]

On Mon, 11 May 2009 02:17:01 +0000, Jim Yanik wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote in
On Sun, 10 May 2009 19:57:57 -0400, Spehro Pefhany
On Sun, 10 May 2009 14:53:10 -0700, the renowned John Larkin

[snip]

Why do we want to put humans back on the moon?

Empire

To establish a settlement, so Sheriff Joe can have a tent city on the
moon, for incarcerating Democrats ;-)

we should incarcerate them in a communist or Muslim country.Maybe both.

But First, kill all the politicians and bureaucrats.

Then, I'd appoint Jim official judge, jury, and executioner of every
person he deems to be a "liberal weenie" and issue him an exquisite
custom-made executioners' ax, so he can carry out his duty forthwith!

Single-handedly, he can eradicate this scourge of freedom-lovers and
peacenicks! (might take awhile, but who counts?)

Let's see how long it takes before one of these "liberal weenies" turns
out to be packing and blows his alleged brains out! >:->

Plus, it'd be a helluva show to watch him there in his hood and ax,
(and probably a loincloth) trying to carry out sentence! ;-D

Cheers!
Rich

 

[Eeyore]

Jon Kirwan wrote:

Epica Dome C goes back another 300kyr, as well.

Going back 300,000 yrs is no help at all. It's bizarre you should even mention it.

Graham

 

[Rich Grise]

On Sun, 10 May 2009 12:06:59 -0700, Tim Williams wrote:

Question the first: where to find transformer (or inductor) cores?

http://www.google.com/

Good Luck!
Rich

 

[Eeyore]

John Larkin wrote:

On Sun, 10 May 2009 17:02:39 -0400, "Martin Riddle"
martin_rid@verizon.net> wrote:

Apparently this will never happen again. Because of the Hubble service
mission, Endeavour is ready in case a rescue is needed since they are
not going to the space station.

see thumbnail 9 for a view of pads 39 A & B

http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts125/multimedia/gallery/gallery-index.html


Crazy. For the price of one repair trip, we could have funded dozens
of ground-based telescopes with resolution superior to Hubble and many
decades of lifetime each. Throw in a few expendable UV and gamma-ray
satellites too.

Pity the space station isn't usable as a telescope platform. At least
it might claim to have a use.

Read Chaisson's book, The Hubble Wars.

I thought the objective of Hubble was to remove atmospheric effects.

Graham

 

[Eeyore]

Rich Grise wrote:

Of course, if we cut the military down to a sane level .....

In the USA ? You must be kidding.

Graham

 

[John E.]

Why do we want to put humans back on the moon?

Employment. Ya gotta spend $$ to employ all those hands.

Ever since the end of WW II the best our government can come up with is 1)
build military stuff and 2) build space stuff.
--
John English

 

On May 3, 12:23 am, Dave <dave_and_da...@Juno.com> wrote:

On May 2, 7:15 pm, Mark-T <MarkTanne...@gmail.com> wrote:

DId anyone here see the problem presented in
the Science section of NY Times last week?
Quite startling, to see something so sophisticated
in a 'general readership' publication.

Is it solvable without a calculus of variations approach?

I solved this when it appeared in rec.puzzles in 1992 (using a duck
and a fox).

Seehttp://groups.google.com/group/rec.puzzles/msg/050273ed70e4a9f6

The bottom line is that there is a strategy by which the rabbit can
escape as long as the agent can run no more than v =
4.6033388487517003525565820291030165130674... times as fast as the
rabbit can swim. The number v is the reciprocal of the solution of the
transcendental equation sqrt(1-r*r) = r*(pi+arccos(r)), which can be
derived using trigonometry.

Dave

I computed the rabbit's fastest escape for various values of v (the
agent's maximal speed), assuming the rabbit's maximal speed is 1
and the pond's shore is the unit circle.

We may assume, without loss of generality, that the agent begins at
the point (1,0) running counterclockwise, and that, from the agent's
point of view, the rabbit never goes left of the center of the pond.
(If the rabbit did so, we could construct an equivalent solution in
which he did not.) We may also assume that the agent runs at full
speed the entire time (the solutions in which he slows down to stop
the rabbit from cutting behind him being of little interest).

The fastest escape for the rabbit involves a circle of diameter 1/v
whose top is at the pond's center. When the rabbit runs at full
speed counterclockwise on this circle, he keeps the pond's center
between him and the agent (until the agent gets to (-1,0)). For
any given spot on the pond's edge where the rabbit might try to
escape, his fastest route there (without going left of the pond's
center from the agent's point of view) is to run along this
circle until he can run straight to his exit point without
crossing through the circle. (The solution for the maximal value
v given by Dave is for the rabbit to run a semicircle, then to
continue straight (in the positive x direction).) Using paths of
this form for arbitrary v, one can solve numerically for the
first escape point that allows the rabbit to reach that point at
the same time as the agent (tie goes to the rabbit).

Here are some escape times t_e for various values of v:

v <= pi: t_e = 1
v = 3.5: t_e = 1.0011722480824568763140554691535330067350...
v = 4 : t_e = 1.0173266236654672461422542182088696225446...
v = 4.3: t_e = 1.0511345079733767600617899255156714598171...
v = 4.5: t_e = 1.1118849008932825665138398791684589180820...

For the critical value given by Dave,

v_c = 4.6033388487517003525565820291030165130673...
(last digit "3" not "4" because I'm truncating, not rounding),

the escape time is

t_e(v_c) = 1.3173494248307199060775592744716826605635...

Slightly smaller values of v yield significantly shorter escape
times:

t_e(v^c - 10^-2) = 1.2146176261268462636077456248661081871567...
t_e(v^c - 10^-3) = 1.2685499374063007502760823717840407058122...
t_e(v^c - 10^-4) = 1.2945402874735326613302923323908998597116...
t_e(v^c - 10^-5) = 1.3067373155331437760247440575734966228130...
t_e(v^c - 10^-6) = 1.3124192755216122410040697316416725441298...

Exploring this asymptotic behavior numerically yields

t_e(v^c - eps) = t_e(v_c) - k eps^(1/3) + O(eps^(2/3)), where

k = 0.4933500252621480311919413384450341753698...

-Jim Ferry
Metron, Inc.
f rr @m tsc .c m
e y e i o

 

[Jim Yanik]

John E. <incognito@xbjcd.com> wrote in
news:0001HW.C62DC048040CDF96B04709AF@news.sf.sbcglobal.net:

Why do we want to put humans back on the moon?

Employment. Ya gotta spend $$ to employ all those hands.

Ever since the end of WW II the best our government can come up with
is 1) build military stuff and 2) build space stuff.

BOTH of which speeds up progress,develops lots of new
processes,materials,and inventions.
Much of that gets developed into civilian uses.

the space race was a great spur for electronics and medical.
and it creates good paying,productive jobs.

Just like auto racing used to bring new ideas and better autos.
(until they developed "formula" racing like NASCAR,that halted
development.NASCAR is now just entertainment;Circus.)

--
Jim Yanik
jyanik
at
kua.net

 

[Richard the Dreaded Liber]

On Fri, 08 May 2009 17:39:42 +0000, Richard the Dreaded Libertarian wrote:

On Thu, 07 May 2009 14:00:35 -0700, RichD wrote:

Why is it, on paper currency the portrait is full
face, while on coins, it's profile?

Why don't you emulate Madalyn Murray O'Hair, and try to get it taken off?
http://www.google.com/search?q=madalyn+murray+o%27hair

Wait a minute! You're a Canuck! It's not your call anyway! And you don't
even USE the things!

Sorry, this was supposed to be in reply to DfBC, in response to his bitch

about "in God we trust" on American money.

Apologies for any confusion.

Thanks,
Rich

 

[Okkim Atnarivik]

On Mon, 11 May 2009 18:25 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

www.nasa.gov/topics/earth/features/world_avoided.html

hole this article is pure fiction

I see. I thought those guys would have at least read the 'Education'
page of their own institution http://ozonewatch.gsfc.nasa.gov before
attempting the simulation. The page e.g. links to
http://www.atm.ch.cam.ac.uk/tour/part3.html
where the role of the cold clouds is recognized. But perhaps those
simulation guys ignored all this.

6. The ozone hole does no occur at the North Pole

I read from somewhere that one of the proposed mechanisms is that
stratosphere would become colder over the arctic, too, once the
greenhouse gases create an insulation between the lower and upper parts
of the atmosphere. Presuming that the greenhouse effect is real, of
course. Naturally, models are no substitute to the real world.

http://tinyurl.com/p3xbz7

Regards,
Mikko

 

[Rich the Newsgroup Wacko]

On Sat, 09 May 2009 10:35:05 +0000, Jasen Betts wrote:

On 2009-05-08, Richard the Dreaded Libertarian <freedom_guy@example.net> wrote:
On Fri, 08 May 2009 16:04:52 +1000, David L. Jones wrote:

BTW, is it just me or are US greenbacks the ugliest currency going around?

No, it's just you. ;-D

But seriously, do you mean the old, all-green ones, or the new Monopoly
money?

You know, there would be no counterfeiting if we went back onto the
gold standard, and actually spent gold! ;-P

if it was gold dust, possibly.

Gold coinage and bullion has been counterfeited in the past.

How about "gold-pressed latinum"? ;-)

Cheers!
Rich

 

[Rich the Philosophizer]

On Fri, 08 May 2009 20:20:13 -0700, D from BC wrote:

On Fri, 08 May 2009 17:32:44 GMT, Rich the Philosophizer

I happen to know God is real because I can feel Her inside me.

That's just intestinal gas..

No, it's Kundalini.

Gamblers 'feel' they will win.. Then don't win..
The feeling is self generated..

That's just fantasy. Notice you put "feel" in quotes. Ask most people how
they feel and they'll start, "Well, I feel that..." and proceed to tell
you what they think, or fantasize.

Maybe intestinal gas is a better metaphor - do you know when you
have to fart? The Mother is felt by the same sensory system, but, as
I've said, in the form of Kundalini, She feels infinitely better.
Actually, She feels like Freedom. ;-)

And I keep wondering, why is it any skin off your nose if I decline to
convert to your religion of atheism?

Thanks,
Rich

 

[Rich the Philosophizer]

On Fri, 08 May 2009 21:09:33 -0700, D from BC wrote:

If anyone sees, hears or feels leprechauns they should be checked for
schizophrenia, paraphrenia or other psychotic disorders.

You still haven't answered my question!

What exactly is it about you that makes it so important to you to
convince everyone that atheism is "The Truth"?

You're worse than any Bible-thumping fundie; are you still trying to
convince yourself, because Santa didn't bring you that pony?

Thanks,
Rich

 

[Rich Grise]

On Sat, 09 May 2009 08:21:08 +0000, Jasen Betts wrote:

On 2009-05-08, Richard Cranium <dufus@bunghole.com> wrote:
On 8 May 2009 08:57:50 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:
On 2009-05-07, Richard Cranium <dufus@bunghole.com> wrote:
Please take this as a "Get Well Soon" card from alt.video.dvd.

go away Dick Head.

Did something I said offend you?

Perhaps you are a different "Richard Cranium"

Well, a cranium isn't the whole head - just the bone. So it could be Dick
Bonehead. ;-)

Cheers!
Rich

 

[John Devereux]

Eeyore <rabbitsfriendsandrelations@hotmail.com> writes:

John Larkin wrote:

On Sun, 10 May 2009 17:02:39 -0400, "Martin Riddle"
martin_rid@verizon.net> wrote:

Apparently this will never happen again. Because of the Hubble service
mission, Endeavour is ready in case a rescue is needed since they are
not going to the space station.

see thumbnail 9 for a view of pads 39 A & B

http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts125/multimedia/gallery/gallery-index.html


Crazy. For the price of one repair trip, we could have funded dozens
of ground-based telescopes with resolution superior to Hubble and many
decades of lifetime each. Throw in a few expendable UV and gamma-ray
satellites too.

Pity the space station isn't usable as a telescope platform. At least
it might claim to have a use.

Read Chaisson's book, The Hubble Wars.

I thought the objective of Hubble was to remove atmospheric effects.

They came up with ways to do that on the ground. I think they use
computer controlled dynamically deformable optical elements to
compensate for the uneven refraction of the atmosphere.

--

John Devereux

 

[Rich Grise]

On Fri, 08 May 2009 14:42:33 -0600, don wrote:

I just found a bag of AM2901 FOUR-BIT BIPOLAR MICROPROCESSOR SLICE.

http://pdf1.alldatasheet.com/datasheet-pdf/view/140822/AMD/AM2901BDC.html

Oh, man! I used to sit and read their data book and drool. ;-) I've seen

the main board of a PDP-8, and noticed that it was a bit-slice. I've
worked with the National IMP-16, which was a bit-slice, and once at
Control Data Magnetic Peripherals Division, they had a processor that
they called "The Enhanced Normandale Controller-Tester", since as a
peripherals division, MPI didn't officially make processors. It was a
bit-slice with TTL RAM; at the time I had an 8008 running at about 1
MHz; the ENCT had a 168 nsec instruction cycle, and was 16 bits wide
(4X 74181).

They were fun, but I never got into them to the depth I wanted to.

Cheers!
Rich