Odds and ends

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Mark
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Re: Odds and ends

Post by Mark » Thu Mar 26, 2009 3:10 am

Some snorkel stuff that may in some way pertain to "snorkelers" or pulsejet intakes, a curious breathing perspective/calibration. ha

DA AquamasterJuly 23rd, 2004, 08:41 AM
There is a compromise involved in tube diameter. A larger air will allow more airflow with less restriction, but the internal volume of the snorkel is another dead airspace (along with your mouth and throat) that you have to overcome to move air in and out of your lungs. So too small a tube diameter increases breathing resistance while too large a tube diameter negatively impacts efficiency in getting oxygen to your lungs and in getting carbon dioxide out of your lungs.
Snorkle lenght also effects the volume of the snorkel so a longer snorkel will also have more dead air space to overcome. Pressure effects aside, longer snorkels would not be practical as the longer the snorkel, the less efficient it would be until you reach the ultimate lenght where your lungs lack the volume to move any useful amount of air through the tube.
http://www.scubaboard.com/forums/archiv ... 64980.html

More meager snorkel tidbits with humor, a valved design.
“Learning to use this thing is tricky. My teammate and friend, Dan, has not bonded with his snorkel because he can’t figure out how to turn with it. I tell him his snorkel is his friend. He scoffs and says, "My friends don’t try to kill me every time I turn!" So it takes some practice. What is really nice about these snorkels is their one-way valve in the bottom. If you blow with a powerful puff after a turn, water will shoot out the top of the snorkel and the bottom of the one-way valve. It’s really cool, but you have to remember to keep enough air in your lungs to puff the water out. Like I said, once you figure out how to turn and breath with this thing, it’s relaxing to wear.
http://www.gizmag.com/go/6131/
Just another design.
http://www.123scuba.com/p-SN540.html
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Mark
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Re: Odds and ends

Post by Mark » Fri Mar 27, 2009 12:36 am

Curious presentatioin. I wonder if one could make/design a pleasing pulsejet or jam jar paperclip for our world?
http://www.joethepeacock.com/2009/03/aw ... it-wtf.php
http://urbanlivingshop.com/dogbonepaperclip.aspx
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pezman
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Re: Odds and ends

Post by pezman » Sat Mar 28, 2009 7:43 pm


Mark
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Re: Odds and ends

Post by Mark » Thu Apr 02, 2009 2:40 am

Visual Perception of Stochastic Resonance
http://www.umsl.edu/~neurodyn/assets/pdf/VisualSR.pdf
http://www.umsl.edu/~neurodyn/about/about.html

Origin of the word "dither"
…one of the earliest [applications] of dither came in World War II. Airplane bombers used mechanical computers to perform navigation and bomb trajectory calculations. Curiously, these computers (boxes filled with hundreds of gears and cogs) performed more accurately when flying on board the aircraft, and less well on ground. Engineers realized that the vibration from the aircraft reduced the error from sticky moving parts. Instead of moving in short jerks, they moved more continuously. Small vibrating motors were built into the computers, and their vibration was called dither from the Middle English verb "didderen," meaning "to tremble." Today, when you tap a mechanical meter to increase its accuracy, you are applying dither, and modern dictionaries define dither as a highly nervous, confused, or agitated state. In minute quantities, dither successfully makes a digitization system a little more analog in the good sense of the word. – Ken Pohlmann, Principles of Digital Audio[1]
http://en.wikipedia.org/wiki/Dithering

"This paper reports a new finding on functionalities of trembling, the bodily manifestation of fear and joy. We consider trembling of a physically-simulated agent consisting of a vision system and a neural system. It is demonstrated that the noise to visual streams generated by trembling enhances signal to noise ratio of the neural system."
http://www.springerlink.com/content/q666x10t47449285/
http://resources.metapress.com/pdf-prev ... ze=largest

History
The concept of stochastic resonance was invented in 1981-82 in the rather exotic context of the evolution of the earth's climate. It has long been known that the climatic system possesses a very pronounced internal variability. A striking illustration is provided by the last glaciation which reached its peak some 18,000 years ago, leading to mean global temperatures of some degrees lower than the present ones and a total ice volume more than twice its present value. Going further back in the past it is realized that glaciations have covered, in an intermittent fashion, much of the Quaternary era. Statistical data analysis shows that the glacial-interglacial transitions that have marked the last 10*6 years display an average periodicity of 10*5 years, to which is superimposed a considerable, random looking variability (see Fig. 1). This is intriguing, since the only known time scale in this range is that of the changes in time of the eccentricity of the earth's orbit around the sun, as a result of the perturbing action of the other bodies of the solar system. This perturbation modifies the total amount of solar energy received by the earth but the magnitude of this astronomical effect is exceedingly small, about 0.1% The question therefore arises, whether one can identify in the earth-atmosphere-cryosphere system mechanisms capable of enhancing its sensitivity to such small external time-dependent forcings. The search of a response to this question led to the concept of stochastic resonance. Specifically, glaciation cycles are viewed as transitions between glacial and interglacial states that are somehow managing to capture the periodicity of the astronomical signal, even though they are actually made possible by the environmental noise rather than by the signal itself. Starting in the late 1980's the ideas underlying stochastic resonance were taken up, elaborated and applied in a wide range of problems in physical and life sciences.
http://www.scholarpedia.org/article/Sto ... _resonance
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Mark
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Re: Odds and ends

Post by Mark » Sat Apr 11, 2009 6:06 pm

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Mark
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Re: Odds and ends

Post by Mark » Sat Apr 18, 2009 1:44 am

(Aluminum oxide)
Rubicon Technology's 441-lb bulk sapphire superboule, on display at the SPIE Defense, Security and Sensing Conference in Orlando.
http://www.photonics.com/Content/ReadAr ... leID=37086
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Mark
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Re: Odds and ends

Post by Mark » Sat Apr 18, 2009 2:10 pm

Of things/effects inbetween.
http://www.energeticstechnologies.com/
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Mark
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Re: Odds and ends

Post by Mark » Sun Apr 19, 2009 9:32 pm

What if our tech is good enough?
Incremental improvements just don't get us excited
http://www.techradar.com/news/world-of- ... s&attr=all
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Mark
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Re: Odds and ends

Post by Mark » Sun Apr 19, 2009 9:48 pm

Sorry Stereo, But Beatles in Mono Rocks a Lot More
http://i.gizmodo.com/5216258/sorry-ster ... a-lot-more
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Mark
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Re: Odds and ends

Post by Mark » Sun Apr 19, 2009 10:18 pm

"Changing the way vehicles move."
http://www.youtube.com/watch?v=tPmC4KPvOfg
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Mark
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Re: Odds and ends

Post by Mark » Sun Apr 19, 2009 10:41 pm

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Mark
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Re: Odds and ends

Post by Mark » Fri Apr 24, 2009 1:59 am

"Unlike conventional lasers, which use mirrored cavities to amplify light, the LCLS is a free-electron laser, creating light using free-flying electrons in a vacuum. The LCLS uses the final third of SLAC's two-mile linear accelerator to drive electrons to high energy and through an array of "undulator" magnets that steer the electrons rapidly back and forth, generating a brilliant beam of coordinated X-rays. In last week's milestone, LCLS scientists used only 12 of an eventual 33 undulator magnets to generate the facility's first laser light."
http://home.slac.stanford.edu/pressrele ... 090421.htm
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Mark
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Re: Odds and ends

Post by Mark » Fri Apr 24, 2009 2:24 pm

New pulsejet or jam jar ignition system and throttle control? ha
http://www.washingtonpost.com/wp-dyn/co ... 9042204139

The movie.
http://www.washingtonpost.com/wp-dyn/co ... 9042204139
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Mark
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Re: Odds and ends

Post by Mark » Fri Apr 24, 2009 11:36 pm

"Michigan University chemists created a zinc-oxide crystal riddled with tiny pores that has the highest surface area of any material in the world."
"Each time a hydrogen molecule hits the wall the hydrogen sticks for a fraction of a second, the product of what’s known as the London dispersion force." http://www.technology.am/zinc-oxide-cry ... 34110.html
http://www.chem.purdue.edu/gchelp/liquids/disperse.html

"To understand London dispersion forces, think of the electrons in a molecule as a constantly changing cloud."
http://www.cartage.org.lb/en/themes/sci ... ersion.htm
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Mark
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Re: Odds and ends

Post by Mark » Sun Apr 26, 2009 2:42 pm

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