Adiabatics

Phil Stein wrote in news: snipped-for-privacy@4ax.com:

Analog vs. digital.

len.

all of existence is quantum at every scale

analog effects are an illusion

- iz

Le> Analog vs. digital.

Hey!! I resemble that remark! 8^)

AstronMike

Since I've re-read my post, I may as well point out that high "g" really only helps in the indirect sense of producing a dense atmosphere since the weight of the balloon structure and payload mass (= lift force required) increase with g as well. This means that "x" is really a mass ratio of structure+payload divided by the displacement mass of the balloon. Ballooning is therefore governed by parameters similar to those governing rockets, such as structure+payload mass fraction (ka-ching! the rocket tie-in!). One could extend this analysis to light gas balloons and submarines as well, like the Cartesian diver.

Brad Hitch

... now, back to your regularly scheduled OT diatribe....

I don't agree. there are an infinite number numbers between 0 and 1, for that matter, there are an infinite number of transcendental numbers between every number between 0 and 1. how can that be quantized?

did you read the article about quantum loop gravity in this month's Scientific American? what do you think about that?

numbers are symbols, they have no reality and do not exist apart from the mind. When applied to things they represent quantities. You can only divide a _thing_ a finite number of times; e.g.; you cannot have a half of a string (or so superstring theory supposes). Hence reality is quantized

I'll agree that imagination is something entirely different, but will argue that imagination is not existence. Objective reality is not one of its properties.

no, I haven't. But it sounds like its worth reading.

did you read

"The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory", by Brian Greene

I found the part on quantum fluctuations very intriguing

- iz

FWIW, Airy disks observed in light from distant galaxies apparently contraindicate quantized time:

Brad Hitch

interesting

but what if portion of the light was out of phase with other portions art the point of origination? That out of phase relationship would been preserved though a trip of fixed speed until the destination.

- iz

Brad Hitch wrote:

If the APCP motor is well designed, delivered total impulse (ISP) is only slightly reduced, but the the trust is lowered and the burn time lengthened. This may result in lower average airspeed that may help balance the denser air WRT drag. YMMV.

Alan

Total impulse is not the same as specific impulse, of course.

More than "slightly", especially for the lower burnrate propellants used in HPR and EX. More so for ANCP. The lower initial temperature of the propellant reduces the efficiency of the burn, lowering the burnrate and chamber pressure, reducing the efficiency. Burn time is increased but total impulse and specific impulse are reduced measureably.

If the ballistic coefficient is low, as in modrocs and most HPR, it may be a balancing act. Some simulations would give insight to that.

About 12 years ago, at a NAR regional contest ("weenie rocketry alert! ;) I kept my motors in my pocket all day on a cold day. I won both altitude events. Coincidence? Well, at least I had some people there convinced! :)

-John DeMar

Thanks Pete! All this time I thought "Adiabatics" was an eating disorder.

Got to love rmr! ; )

Randy

Chris, if you want to violate accepted netiquettte, that's one thing (it's not really "okay", but there are worse sins). Don't implicitly criticize others for doing it the accepted way.

Scott Orr

Technically time doesn't pass for the photon since it travels at the speed of light, and I believe the Airy disk is caused by interference in the telescope itself. The classic two-slit experiment doesn't require coherent light to work and I think it is still considered to have a very odd result. I assume these guys at NASA and UAH understand the physics and its implications much better than I. Frankly, Newtonian physics, 19th century thermodynamics, and one-dimensional flow approximations are enough to solve 90% of my problems to the level of being dominated by experimental errors and measurement uncertainties. I'm generally pretty happy if I can predict or correlate heat transfer coefficients to within 20% or so.

"Is that a D12 in your pocket, or are you just..."

uhhhh...forget it!

Ok, not always a bad thing.

~ Duane Phillips.

Don't mess with Chris. He's "Special"

Phil Ste>>

Phil Stein

So is light god?

Of course, but for the case here with a motor of fixed propelant mass, "total Impulse", and "ISP" can be used interchangably. To be clearer, instead of saying "(ISP)", I could have said ", and hence ISP,", but I like to conserve keystrokes.

Then your motors are simply not well designed, especialy for use at cold temperatures.

Only if your simulations properly account for motor performance with varriation in intital motor temperature.

Alan