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Ein Stein
I’ve been fascinated by aperiodic tilings of the plane since Martin Gardner first wrote about them in Scientific American. In the 1960s, Robert Berger discovered a set of 20 426 prototiles or tile-types that can tile the plane but only with no translational periodicity — a wonderful mix of the expected and the surprising, a kind of…
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Gossamer Flight
As a kid, I devoured the pages of Popular Science magazine and was fascinated by the quest for human-powered flight: Was a flying bicycle possible? In the mid 1970s, I read that aerospace engineer Paul MacCready had assembled a team to build a large, lightweight, human-powered aircraft that could be rapidly repaired and redesigned. In…
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The Cupola
In the sky is a castle, built in free fall, brick-by-brick, where the sun rises and sets every ninety minutes. The castle derives its energy from sunlight and recycles its water. Sealed against a vacuum, its inhabitants float and glide through its passageways and gaze down at Earth through its expansive cupola. In an earlier…
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The Falls
1930s businessman Edgar Kaufmann Sr. and his family lived in Pittsburgh Pennsylvania. Kaufmann owned a rural retreat outside the city and wanted a weekend home there. He assumed his 67-year-old architect would design the home with a good view of the Bear Run waterfall. Instead, the architect designed the home on the waterfall. Frank Lloyd…
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The Burj
The tallest structure in the world since 2008, Burj Khalifa (or Khalifa Tower) is the fantasy skyscraper of my childhood. Designed by Skidmore, Owings & Merrill (SOM), with Adrian Smith and Bill Baker as chief architect and engineer, the Burj is aesthetically and structurally magnificent. No single photo can do the Burj justice, but the…
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Engine of Computation
Chaotic systems are extremely sensitive to the initial conditions and parameters that define them. Minute perturbations of the parameters can even convert chaotic motion to periodic motion. This alliance between control methods and physics — cybernetical physics — opens the door to many applications, including dynamics-based computing. We recently published an article that introduces nonlinear…
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Frustration & Perpetual Motion
Momentum conservation (or Newton’s third law) ensures two-way or bidirectional coupling for typical media like guitar strings and spring mattresses. One-way or unidirectional coupling enables the propagation of solitary waves or solitons with diverse behaviors in otherwise dissipative media, but at the expense of both momentum and energy conservation. Nevertheless, one-way media are possible, provided…
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Harvesting Wind Energy for Signal Detection
Wind is free and ubiquitous and can be harnessed in multiple ways. We recently published an article in the Physical Review demonstrating mechanical stochastic resonance in a tabletop experiment that harvests wind energy to amplify weak periodic signals detected via the movement of an inverted pendulum. Unlike earlier mechanical stochastic resonance experiments, where noise was added via…
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Raptor Interplanetary Transport Engine
Why has SpaceX chosen methane to fuel its Raptor rocket engine? Robert Goddard’s first rockets used liquid oxygen O2 or LOX and gasoline. The Saturn V moon rocket first stage used LOX and refined kerosene. The Saturn V second stage used LOX and hydrogen that burn to water in my favorite chemical reaction, 2H2 + O2…
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First Deep Space Walk
In 1971 during Apollo 15’s return from Earth’s moon, astronaut Al Worden performed the first deep space walk nearly 200 000 miles from Earth to recover external service module film canisters that had mapped the lunar surface. Worden was able to pause and orient himself to simultaneously see both Earth and moon as disks against…
Author: John F. Lindner
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Nice post, John! Thanks for writing these. I always enjoy them.
David Smith’s ein stein is an awesome shape!
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Thanks, Mark! I enjoy reading your posts as well.