HDTenEightyP/NetNews huggingface dataset:
From: torbenm@diku.dk (Torben AEgidius Mogensen)
Newsgroups: sci.math
Subject: Re: Penrose Tiles / Beatty Seq's.
Date: 12 Oct 92 11:44:12 GMT
Organization: Department of Computer Science, U of Copenhagen

shaw@toadflax.UCDavis.EDU (Rob Shaw) writes:

>The are only a handful of Penrose (kite+dart) tilings as
>shown by taking infinite strips across the tiling. These
>strips come in a sequence containing "thin" and "thick"
>strips. The sequence is a Beatty sequence.

>Something like 

>10010101001010010010010...

>Could be a Beatty sequence, since one of the two elements
>always appears alone, and the other appears alone or in
>pairs.

>This book also described how successive powers of the 
>golden ratio, rounded up and down form complementary
>Beatty sequences, and moreover, that one of these
>sequences is something that was previously thought
>to only be computable by some recursive method that 
>required calculating all the terms preceding the 
>desired one.

The algorithm that uses powers of the golden ratio may not be any more
efficient than the method calculating all preceeding terms, as you
will ned progressively higher precision in the arithmetic, with
progressively more computing time as a consequence.

	Torben Mogensen (torbenm@diku.dk)
Newsgroups: sci.math
From: chr09tk@vmsa.technion.ac.il
Subject: Topological Question
Organization: Technion, Israel Institute of Technology
Date: Mon, 12 Oct 1992 14:32:49 GMT

Hello!

Can anyone help me with the folowing topological question:
Is there a connected and locally connected topological space which is not path
connected? 
Is there such a space which is also compact?

Thanks in advance,
Guy 
Xref: sparky sci.math:13211 sci.physics:16525
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.math,sci.physics
Subject: Re: "The Universe of MOTION" (book review)
Date: 15 Oct 92 00:37:22 GMT
Article-I.D.: husc8.mcirvin.719109442

jbaez@riesz.mit.edu (John C. Baez) writes:
(quoting McElwaine's latest paean to Dewey B. Larson,
 in a Crackpot Index trial run)

>               Most books and journal articles on the subject of 
>          astrophysics are bristling with integrals, partial 
>          differentials, and other FANCY MATHEMATICS.  In this book, by 
>          contrast, mathematics is conspicuous by its absence, except 
>          for some relatively simple formulas imbedded in the text.  
>          Larson emphasizes CONCEPTS and declares that mathematical 
>          agreement with a theory does NOT guarantee its conceptual 
>          validity. 

Expressing disdain for the elitism of "fancy mathematics" must surely
merit extra credit on the Crackpot Index.  Or should we limit the
number of items deserving of credit, lest this resemble those old
Usenet standbys, the Purity Test and the Star Trek Drinking Game?
-- 
Matt McIrvin, posting nonsense again 
Newsgroups: sci.math
From: mab@wdl39.wdl.loral.com (Mark A Biggar)
Subject: Re: Question on real numbers
Organization: Loral Western Development Labs
Date: Thu, 8 Oct 1992 23:32:40 GMT

In article <1992Oct8.211117.19295@rz.uni-karlsruhe.de> vhansen@ipfs.bau-verm.uni-karlsruhe.de (Wolfgang von Hansen) writes:
>is it possible to express any real number x with the following term
>
>x = a + rb;  a, b \in Q; r \in R, r const.
>
>Some more words to explain what I mean:
>I was wondering if there is an analogon between the real numbers and
>the complex numbers.
>
>My idea is to write any real number as a pair of rational numbers
>one of them multiplied with a constant real number r (see above).
>a is not necessarily (spelling? ;-) different from null. A useful value
>for r may be \sqrt(n), n \in N, because r * r = n is easy to handle.
>This representation of the real numbers might improve the speed
>and/or accuracy of algorithms on computers since all calculations are
>done with rational numbers.
>
>There are some things left to do:
>1. Prove if it is (not) possible.

No you can't do this.  The set of all pairs of rationals (a,b) in only
countably infinite, therefore the set {a+rb} is countable, But the set
R in uncountably infinite, therefore R != {a+rb}.  As a counter example
to you suggestion that you use sqrt(n) lets choose sqrt(2), and lets try
to construct sqrt(3) using your system (I'm going to use s2 ans s3 for
sqrt(2) and sqrt(3) to save typing.

s3 = a + s2 * b                                  (a & b rational)
s3 = p/q + s2 * (m/n)                            (p,q,m,n integers)
3 = p^2/q^2 + 2*s2*(m/n) + 2(m^2)/(n^2)          (square both sides)
3 = (p^2/q^2 + 2(m^2)/n^2) + 2*s2*(m/n)

Thus 3 is the sum of a rational and a irrational, which is impossible.

--
Mark Biggar
mab@wdl1.wdl.loral.com


Newsgroups: sci.aeronautics,rec.travel.air
From: martin@datacomm.ucc.okstate.edu (Martin McCormick)
Subject: Voice and Data Recorders
Organization: Oklahoma State University, Stillwater, OK
Date: Tue, 13 Oct 1992 18:42:56 GMT


As with every major airliner accident, the topic of the "black box" comes
up again.  I have always been curious about the actual technology involved,
here.  All I really know about flight and voice recorders is that they 
have been around since the fifties.  They are really orange- colored to make
them as visible as possible and, at least some, have sonar and ELT type
systems to further aid in their recovery.
	What I would like to know is:  What type of medium is used for the
recording?  How long does a tape or what ever else is used last?  Does the
voice recorder get power from the aircraft's power system or is there an
inturnal battery so that it can continue to record if power is lost?
  It will be interesting to hear from anybody who has actually worked with these
systems and can tell us about the nuts and bolts of voice and data recorders.

Martin McCormick WB5AGZ   Stillwater, OK
O.S.U. Computer Center Data Communications Group
Newsgroups: sci.aeronautics
From: kanekawa@oahu.cs.ucla.edu (Nobuyasu Kanekawa)
Subject: Re: El Al 747 Crash in Amsterdam
Organization: UCLA, Computer Science Department
Date: Thu, 8 Oct 92 23:53:29 GMT

In article <167@newave.newave.mn.org> john@newave.newave.mn.org (John A. Weeks III) writes:
>In <1992Oct7.005552.5844@athena.mit.edu> cid@athena.mit.edu (Derek H Cedillo):
>> I think boeing may have made a big boo-boo somewhere.
>
>I don't think so.  The 747 is an extremely safe aircraft.  With all of the
>miles and flights that 747's complete each day, there would be many more
>crashes if there were any "big boo-boos" in the aircraft.

I agree.  And we can enjoy SCALE MERIT effect in safety.  :-)
I heard INS (Inertial Navigation System) became affordable for commercial
airplanes because of 747's scale merit.

Yasu.

-- 
Nobuyasu KANEKAWA  (E-mail address in Japan : kanekawa@hrl.hitachi.co.jp)
From: gt8303a@prism.gatech.EDU (The Great and Mighty Confused)
Newsgroups: sci.aeronautics
Subject: Re: Aurora tidbit
Date: 12 Oct 92 22:05:38 GMT
Organization: Georgia Institute of Technology

In article <1992Oct12.111239.4712@desire.wright.edu> f0408@desire.wright.edu writes:
>	If anyone is interested, I'll try to get a transcript of the lecture
>(or of the more interesting portions of the two hours) from the USAF Museum.

Please do send me (or post here) a transcript.
I'd appreciate it.

Andy Entrekin
gt8303a@prism.gatech.edu

Newsgroups: sci.aeronautics
From: howeird@hplabsz.hpl.hp.com
Subject: CAE/CASE Program Sought
Date: Mon, 12 Oct 1992 20:07:18 GMT
Organization: HP Research Grants Program

I'm posting this for a friend who doesn't have access to this newsgroup.
Please reply via email either to this posting, or the address below.
Thanks!

I'm a grad student doing research on squid locomotion, and suspect that
there is aernautical design and analysis software out there which would help
me greatly in my work. We don't get much information on aero software
out here in the land of the 10-armed mollusk.

Here's what I'm looking for. Something that runs on an IBM-PC compatible,
which will let me input pictures from a videotape, select and area of the
picture (the squid's fin, for example) and have the computer relate the
movement of that area to the movement of the whole squid. I want to be able
to find the speed of waves as they travel along the fin and compare it to
the speed of the squid.

Since I have videotapes of different sizes and types of squid swimming at
different speeds (and this is important, because of the different shapes of
squid fins), I want to be able to capture data from the screen and then
work from there.

All the systems I've seen so far are for linear movement, such as walking
or swimming of the whole animal, but none of them are capable of working
with a system with circular movement, i.e. the wave travels from the front
to the back of the fin and then another wave is generated at the front of
the fin, often while the other wave is still traveling along the fin.

If you can point me toward anything like this, or recommend a newsgroup to
cross-post to, that would be helpful.

Thanks!
Jennifer

JAHOAR@AC.DAL.CA
Dalhousie Univ.
Halifax, Nova Scotia
Canada
Newsgroups: sci.aeronautics
From: cid@athena.mit.edu (Derek H Cedillo)
Subject: Re: El Al 747 Crash in Amsterdam
Organization: Massachusetts Institute of Technology
Date: Fri, 9 Oct 1992 03:51:26 GMT

In article <167@newave.newave.mn.org> john@newave.newave.mn.org (John A. Weeks III) writes:
>In <1992Oct7.005552.5844@athena.mit.edu> cid@athena.mit.edu (Derek H Cedillo):
>> I think boeing may have made a big boo-boo somewhere.
>
>I don't think so.  The 747 is an extremely safe aircraft.  With all of the
>miles and flights that 747's complete each day, there would be many more
>crashes if there were any "big boo-boos" in the aircraft.
>

To me, 2 aircaft that lose 2 engines on the same wing shortly
after take-off within 10 months of eachother is a boo-boo.
Especially when both ended so fatally.  



>Personally, with the 747 doing a circle over a lake with two engines on
>fire, I think the pilot had a responsibility to dump the plane in the
>water rather than flying into a densely populated area loaded with fuel.

I agree with you.  However a survey of 747 pilots said that it is nearly
impossible to recover control of a 747 that loses two engines with 
such little altitude.  actually I think they said Impossible.  
particulaly a heavy loaded plane such as a cargo causes
even more problems.  The first thing they should do is jettison that
fuel.   The pilots did this.  Second thing to do is to regain your altitude.
The jettisoning of fuel would lighten the load to regain control.
The falling rate is something of at least 1500 ft/min i believe,
(please correct me if I am wrong)  In a plane where two engines
are lost as well as the included hydrolic systems,
a 1500 ft/min falling rate doesnt give you much time to react.
I am sure the pilots did thier best.  I could be wrong, since
I am basing my view on preliminary reports.  Thus, 
anyone can feel free to correct me.


>
>-john-
>
>-- 
>==============================================================================
>John A. Weeks III		(612) 942-6969		    john@newave.mn.org
>Newave Communications, Ltd.			    ..!uunet!tcnet!newave!john



Derek H Cedillo
Organisation: European Space Technology Centre (E.S.T.E.C)
Date: Friday, 9 Oct 1992 13:19:31 CET
From: <FNOTMAN@ESTEC.BITNET>
Newsgroups: sci.aeronautics
Subject: Re: El Al 747 Crash in Amsterdam
 <1992Oct7.005552.5844@athena.mit.edu> <167@newave.newave.mn.org>
 <1992Oct9.035126.14109@athena.mit.edu>

>>Personally, with the 747 doing a circle over a lake with two engines o
>>fire, I think the pilot had a responsibility to dump the plane in the
>>water rather than flying into a densely populated area loaded with fue.

>I agree with you.  However a survey of 747 pilots said that it is nearl
>impossible to recover control of a 747 that loses two engines with
>such little altitude.  actually I think they said Impossible.
>particulaly a heavy loaded plane such as a cargo causes
>even more problems.  The first thing they should do is jettison that
>fuel.   The pilots did this.  Second thing to do is to regain your altiude.
>The jettisoning of fuel would lighten the load to regain control.
>The falling rate is something of at least 1500 ft/min i believe,
>(please correct me if I am wrong)

 Surely you contradict yourself here, if control is (or is near) to impossible
then that's more reason to aim for something a big as the Ijsellmeer than such
a small target as the Runway.
 For the record, the Ijsellmeer is what USED to be the ZuiderZee, i.e. it's the
LARGE expance of in-land sea that was dammed to form the great polders and run
to "fresh" water (Shipol is itself below see level). It has to my mind 2
advantages when putting a plane in it :-
 1/ It's a BIG target, even at the bottom end beside Amsterdam (it's narrowest
section), it's about 5 miles across, point NE along it and you's about 20-25
miles of "clear" water (then a road, then another 40 miles due north).
 2/ most of it's pretty shallow.

 I undertood it was 6000 ft and falling at 600/min. Afterall, reports said
crew fought to recover plane for nearly 10 minutes. I would have thought that
after 1st circle they should have headed for water (there's plenty around)
Newsgroups: sci.aeronautics
From: mtissand@magnus.acs.ohio-state.edu (Michael D Tissandier)
Subject: Re: Most evil looking mother that ever flew (was Re: F-23 Dead? Nahh..
Organization: The Ohio State University
Distribution: usa
Date: Wed, 14 Oct 1992 12:13:09 GMT

  I was under the impression that it was a collision between an Israeli
Eagle and an A-4 Skyhawk.  I believe B. Sweetman mentions this in his
YF-22/YF-23 book.  If it was Israeli, it couldn't have been a Strike Eagle.

   --Mike

------------------------------------------------------------------------
  My Dear McClellan:
     If you don't want to use the Army, I should like to
     borrow it for a while.

        ---Abraham Lincoln

                  mtissand@magnus.acs.ohio-state.edu
------------------------------------------------------------------------
Xref: sparky sci.aeronautics:2305 sci.energy:4913
From: jim@netlink.cts.com (Jim Bowery)
Newsgroups: sci.aeronautics,sci.energy
Subject: Re: Revolutionary US Turbine Technology Lost to Germany
Date: 13 Oct 92 16:00:48 GMT
Organization: NetLink Online Communications, San Diego CA

Werner Uhrig writes:
>
> jim@netlink.cts.com (Jim Bowery) writes:
>
>> The revolutionary turbine engine technology I posted about in 
>> here a few months ago was finally accepted by a German firm.
>
>        sorry, but I wasn't paying attention then.  could you
>        provid a published reference pointer, please?  what, who,
>        when, where ?!?  thanks.
 
>>The revolutionary turbine engine technology I posted about in 
>>here a few months ago was finally accepted by a German firm.
 
Yes, I thought I had stated in a later message that it was a combination
of a new(80's) patent and trade secrets that optimize the deficits of 
Tesla's original (1911?) patent based on modern CFD, materials and 
manufacturing techniques.  It resolves major difficulties with bladed 
turbines (except sensitivity to RPM).  
 
However, now that I think of it I might have simply sent that as a 
private communication to someone.
 
The German firm's name is not to be disclosed as yet.

--                    
INTERNET:  jim@netlink.cts.com (Jim Bowery)
UUCP:   ...!ryptyde!netlink!jim
NetLink Online Communications * Public Access in San Diego, CA (619) 453-1115
From: daver@sunspot.ssl.berkeley.edu (David Ray)
Newsgroups: sci.aeronautics
Subject: Need info: 1953 aircraft gyro, ordinance #9064932, need pinout
Date: 8 Oct 1992 20:48:01 GMT
Organization: /etc/organization
NNTP-Posting-Host: sunspot.ssl.berkeley.edu

      I have an aircraft wing roll gyro from ~1953. I want to hook it up
and get it working. There is no information about it except that it was
built to "ordinance #9064932". There is no manufacturer or part number
on it.
      I talked to some gyro experts at Honeywell and they gave me some 
good historical info, but couldn't help locating the spec sheet.
Apparently the "ordinance number" was a government spec that was
issued for military and governement equipment before the current system
of "national stock numbers" was created in the late 1950's.
The gyro experts also told me that it most probably uses a 24V 400Hz
power, as did all aircraft equipment in those days.
      The gyro has about 6 wires. I checked continuity and resistance
across all combinations of the wires, and some of them have resistance
in the 3 to 20 ohm range. These probably go to the windings of the motor
or inductive feedback sensor. I'm afraid to hook up 24V power to it
because I don't want to accidentally burn out a sensor.

Does anybody know wgere I can locate a spec sheet for this gyro?

Dave    daver@sunspot.ssl.berkeley.edu   (510) 527-9010
From: dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 
Newsgroups: sci.aeronautics
Subject: NO
Date: 14 Oct 92 21:03:00 GMT
Distribution: world
Organization: Advanced Computer Concepts BBS, New Rochelle, NY 914-654-1981
Reply-To: dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 

To: airliner-vote@rascal.ics.utexas.edu.

        D/

 * OLX 2.2 * Bring back A-N airways!!    Dick.Zeitlin%acc1bbs@ssr.com
From: john@newave.newave.mn.org (John A. Weeks III)
Newsgroups: sci.aeronautics
Subject: Re: El Al 747 Crash in Amsterdam
Date: 8 Oct 92 01:56:53 GMT
Organization: Newave Communications, Ltd, Lake Wobegon, MN

In <1992Oct7.005552.5844@athena.mit.edu> cid@athena.mit.edu (Derek H Cedillo):
> I think boeing may have made a big boo-boo somewhere.

I don't think so.  The 747 is an extremely safe aircraft.  With all of the
miles and flights that 747's complete each day, there would be many more
crashes if there were any "big boo-boos" in the aircraft.

Personally, with the 747 doing a circle over a lake with two engines on
fire, I think the pilot had a responsibility to dump the plane in the
water rather than flying into a densely populated area loaded with fuel.

-john-

-- 
==============================================================================
John A. Weeks III		(612) 942-6969		    john@newave.mn.org
Newave Communications, Ltd.			    ..!uunet!tcnet!newave!john
Newsgroups: sci.aeronautics
From: johnh@psych.su.oz.au (John Holden)
Subject: Re: El Al 747 Crash in Amsterdam
Organization: Department of Physiology, University of Sydney, NSW, Australia
Date: Wed, 14 Oct 1992 01:39:34 GMT

casper@fwi.uva.nl (Casper H.S. Dik) writes:

>eric@cs.ruu.nl (Eric Nieuwland) writes:

>>According to my information, the plane lost its hydraulics just before
>>it went down. I don't know whether this is speculative or a known fact.

>>My question then is: What can make a 747-200F loose its hydraulics and
>>is there no mechanical back-up?

>No pilot in the world is strong enough to move the control surfaces of
>a 747 by hand. There is mechanical backup for the lowering of the
>landing gear and, presumably, flaps. When your engines are gone from
>the wing, part of your hydraulics go with it.

	The 747 has an excellent control system for flight surfaces. There
are four independant hydraulic systems, each powered by an ADP (air driven
pump from the engine blead air gallery) and an EDP (engine driven pump).
Even with an engine shutdown the EDP will still provide hydraulic power at
reduced rates if the turbine is allowed to free-wheel.

	The four hydraulic systems are split across most of the important
control surfaces, which either have dual actuators or either electric
(ie trailing edge flaps) or pneumatic backups. You need to go into three
failures before control problems set in.

	The loss of hydraulics 3 & 4 would result in loosing one outboard and
the opposite inboard elevators. There is still 100% available rudder to
counteract yaw. With the engines actually missing, one could assume that
the yaw moment would lessen (ie less drag) but there would be lateral trim
problems because of the mass imbalance. If the departing inboard engine
clobbered the elevators as it left; say stalling the elevator trim
(which would be up for climb out), the maximum control forces would be of the
order of 90lbs.

	The main problem given that you could get the lateral trim right,
is that at a high landing weight, gear down and flaps, level flight is
not guaranteed. Gear up would give about 250 f/m climb.

Xref: sparky sci.aeronautics:2276 sci.energy:4894
From: werner@cs.utexas.edu (Werner Uhrig)
Newsgroups: sci.aeronautics,sci.energy
Subject: Re: Revolutionary US Turbine Technology Lost to Germany
Date: 10 Oct 1992 17:37:53 -0500
Organization: CS Dept, University of Texas at Austin
NNTP-Posting-Host: dimebox.cs.utexas.edu

 jim@netlink.cts.com (Jim Bowery) writes:

> The revolutionary turbine engine technology I posted about in 
> here a few months ago was finally accepted by a German firm.

	sorry, but I wasn't paying attention then.  could you
	provid a published reference pointer, please?  what, who,
	when, where ?!?  thanks.
-- 
  werner@cs.utexas.edu |  ..!uunet!cs.utexas.edu!werner | werner@UTXVM.bitnet

              "Free Advice and Opinions -- Refunds Available"
From: dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 
Newsgroups: sci.aeronautics
Subject: 2nd CFV and VOTE ACK: sci
Date: 14 Oct 92 21:12:00 GMT
Distribution: world
Organization: Advanced Computer Concepts BBS, New Rochelle, NY 914-654-1981
Reply-To: dick.zeitlin%acc1bbs@ssr.com (Dick Zeitlin) 

To: airliner-vote-request@rascal.ics.utexas.edu

There's so little traffic on sci.aeronautics, is a further subdivision
necessary?  Am I not getting all the traffic?  The last ten messages
I've received were all from you, and mostly concerning proposed reorgs.

        D/

 * OLX 2.2 * Bring back A-N airways!!    Dick.Zeitlin%acc1bbs@ssr.com
                                        
Newsgroups: sci.aeronautics,rec.travel.air
From: rdd@cactus.org (Robert Dorsett)
Subject: Re: Aplogy to Robert Dorsett & More on El Al Disaster
Organization: Capital Area Central Texas UNIX Society, Austin, Tx
Date: Tue, 13 Oct 1992 05:00:54 GMT

In article <1992Oct12.173032.17438@airdata.socal.com> chris@airdata.socal.com (Chris J. Davis) writes:
>>The cross sectional area of a turbofan such as the CF6-50 (GE's 747-
>>200 powerhouse-BTW what is the PW engine?  it's an old J li7e right?)
>
>it's a JT-9D i believe (Robert?)

It's not every day I have a thread named after me...:-)


In a correspondence, Karl Swartz indicated the airplane was 4X-AXG, 
747-258F, line number, with JT9D-7J engines.

From my handy-dandy P&W engine chart:

	Type: Turbofan.
	
	Used on: 747-100,-200B, C, F, 747SR, 747SP
	
	Engine dry weight, 8850 lbs
	Diameter: 95.6"
	Length: 154.2"
	
	Standard Day Sea Level Static Thrust:
		Dry Takeoff: 50000 lbs
		MCT: 40200 lbs
	
	Thrust Specific Fuel Consumption: 
		Dry Takeoff: 0.370 lbs/hr/lb-thrust
		MCT: 0.354 lbs/hr/lb-thrust
		
	Gas Generator Performance at Dry Takeoff Rating:
		Total Airflow: 1595 lbs/sec
		Bypass ratio: 5.1
		Overall pressure ratio: 23.5
		
	# of Compressor Stages
		Fan: 1
		Low: 3
		High: 11
	
	No. of Turbine Stages:
		High: 2
		Low: 4
	
	No. of combustion chambers: 1



>[...]
>> It would take a lot more than one bird in an engine to cause serious
>> problems like an uncontained failure.
>
> doesn't this depend on the size/mass of the bird?  what about one _big_
> bird?  (no derek, not the one on sesame street).

This is something a lot of people don't seem to appreciate: Schiphol is
notorious for severe bird problems, being close to the sea.  Radome, wing, 
and engine damage is common.  Since birds flying around *may* have 
been big sea birds, I can see how collision with a flock is, at the very 
least, conceivable.

Anyone out there know anything about birds, esp. those that migrate through 
the Amsterdam area?




---
Robert Dorsett
rdd@cactus.org
...cs.utexas.edu!cactus.org!rdd

 Vote on sci.aeronautics.airliners!   See the CFV in news.announce.newgroups,
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Newsgroups: sci.aeronautics