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3D Printing from MIT
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In this video, we show how MIT research continues to push the boundaries of the burgeoning technology of 3-D printing.
The following excerpt is from the MIT news office webpage at http://web.mit.edu/newsoffice/2011/3d-printing-0914.html
"The initial motivation was to produce models for visualization — for architects and others — and help streamline the development of new products, such as medical devices. Cima explains, “The slow step in product development was prototyping. We wanted to be able to rapidly prototype surgical tools, and get them into surgeons’ hands to get feedback.”
3DP technology involves building up a shape gradually, one thin layer at a time. The device uses a “stage” — a metal platform mounted on a piston — that’s raised or lowered by a tiny increment at a time. A layer of powder is spread across this platform, and then a print head similar to those used in inkjet printers deposits a binder liquid onto the powder, binding it together. Then, the platform is lowered infinitesimally, another thin layer of powder is applied on top of the last, and the next layer of binder is deposited." |
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NASA and Caltech Test Steep-Terrain Rover
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Reprinted from JPL News. For the original article and video, click here Engineers from NASA's Jet Propulsion Laboratory and students at the California Institute of Technology have designed and tested a versatile, low-mass robot that can rappel off cliffs, travel nimbly over steep and rocky terrain, and explore deep craters.
This prototype rover, called Axel, might help future robotic spacecraft better explore and investigate foreign worlds such as Mars. On Earth, Axel might assist in search-and-rescue operations. A Web video showing an Axel test-run at the JPL Mars yard is online at:
www.jpl.nasa.gov/video/index.cfm?id=806 . "Axel extends our ability to... |
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How Airplanes Fly
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The simple physics of aerodynamically generated lift and drag and other forces that enable an aircraft to fly is discussed. A fluid flowing past the surface of a body exerts a surface force on it. Lift is defined to be the component of this force that is perpendicular to the oncoming flow direction.It contrasts with the drag force, which is defined to be the component of the surface force parallel to the flow direction. If the fluid is air, the force is called an aerodynamic force. An
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Circular bubbles produced by Whales and Dolph...
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Circular bubbles produced by Whales and Dolphins. A bubble ring is an underwater ring vortex where an air bubble occupies the core of the vortex, forming a ring shape. The ring of air as well as the nearby water spins poloidally as it travels through the water, much like a flexible bracelet might spin when it is rolled off a person's arm. Some scuba divers can create bubble rings by blowing air out of their mouth in a particular manner. Long bubble rings also can form spontaneously in turbulent water such as in heavy surf. Bubble rings and smoke rings are both forms of vortex rings, and are sometimes studied in the field of fluid dynamics. Dolphins and humpback whales have also been seen to create bubble rings. Dolphins sometimes create bubble rings on purpose, seemingly for amusement.
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The Lunar Orbiter: A Spacecraft to Advance Lu...
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1966. The film describes the Lunar Orbiter's mission to photograph landing areas on the Moon. The Orbiter will be launched from Cape Kennedy using an Atlas Agena booster rocket. Once it is boosted in a trajectory toward the Moon, the Orbiter will deploy two-way earth communication antennas and solar panels for electricity. Attitude control jets will position the solar panels toward the sun and a tracker for a fix on its navigational star. The Orbiter will be put in an off-center orbit around the Moon where it will circle from four to six days. Scientists on Earth will study the effects of the Moon's gravitational field on the spacecraft, then the orbit will be lowered to 28 miles above the Moon's surface. Engineers will control the Orbiter manually or by computer to activate two camera lenses. The cameras will capture pictures of 12,000 square miles of lunar surface in 25 and 400 square mile increments. Pictures will be sent back to Earth using solar power to transmit electrical signals. The signals will be received by antennas at Goldstone, CA, and in Australia and Spain. Incoming photographic data will be electronically converted and processed to produce large-scale photographic images. The mission will be directed from the Spac... |
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Aeroelastic Tests of an Eight Percent Scale S...
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Buffet and flutter characteristics of Saturn Apollo mission were studied using a dynamically scaled model. The model was built around a central aluminum tube for scaled stiffness distribution and strength to resist loads imposed during testing. Styrofoam sections attached to the core provided the correct external contours. Lead weights were added for correct mass distribution. An electromagnetic shaker was used to excite the model in its flexible modes of vibration during portions of the test. The model was supported on a sting, mounted by leaf springs, cables and torsion bars. The support system provided for simulating the full scale rigid body pitch frequency with minimum restraint imposed on elastic deflections. Bending moments recorded by sensors on the aluminum tube. Several modified nose configurations were tested: The basic configuration was tested with and without a flow separator disk on the escape rocket motor, tests also were made with the escape tower and rocket motor removed completely. For the final test, the Apollo capsule was replaced with a Jupiter nose cone. The test program consisted of determining model response throughout the transonic speed range at angles of attack up to 6 degrees and measuring the aerodynam... |
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Apollo-Lunar Orbital Rendezvous Technique
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The film shows artists rendition of the spacecrafts, boosters, and flight of the Apollo lunar missions. The Apollo spacecraft will consist of three modules: the manned Command Module; the Service Module, which contains propulsion systems; and the Lunar Excursion Module (LEM) to carry astronauts to the moon and back to the Command and Service Modules. The spacecraft will be launched via a three-stage Saturn booster. The first stage will provide 7.5 million pounds of thrust from five F-1 engines for liftoff and initial powered flight. The second stage will develop 1 million pounds of thrust from five J-2 engines to boost the spacecraft almost into Earth orbit. Immediately after ignition of the second stage, the Launch Escape System will be jettisoned. A single J-2 engine in the S4B stage will provide 200,000 pounds of thrust to place the spacecraft in an earth parking orbit. It also will be used to propel the spacecraft into a translunar trajectory, then it will separate from the Apollo Modules. Onboard propulsion systems will be used to insert the spacecraft into lunar orbit. Two astronauts will enter the LEM, which will separate from the command and service modules. The LEM will go into elliptical orbit and prepare for landing. Th... |
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How to Solve Differential Equations using Mat...
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How to solve differential equations using Mathematica. Demonstrates Solving First Order and Second Order Differential equations and Solving Differential Equations with boundary conditions, i.e. finding the arbitrary constants.
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Effect of gas on voice
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Effect of gas on voice |
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Audio Spectrograms
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A spectrogram is an image that shows how the spectral density of a signal varies with time. Also known as spectral waterfalls, sonograms, voiceprints, or voicegrams, spectrograms are used to identify phonetic sounds, to analyse the cries of animals, and in the fields of music, sonar/radar, speech processing, seismology, etc. The instrument that generates a spectrogram is called a spectrograph or sonograph. The most common format is a graph with two geometric dimensions: the horizontal axis represents time, the vertical axis is frequency; a third dimension indicating the amplitude of a particular frequency at a particular time is represented by the |
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