"For the sake of brevity we will write this number as π; thus π is equal to half the circumference of a circle of radius 1.”
Euler, Leonhard, 1707-1783. Introductio in analysin infinitorum, 1748.
Houghton Library, Harvard University
The Harvard Computation Laboratory at night (ca. 1947)
It was around this time that the lab’s director, Howard Aiken, reputedly predicted that “only six electronic digital computers would be required to satisfy the computing needs of the entire United States.”
Yet Aiken and his graduate students were pioneers in the early days of computing machine design and theory.
"Within a few years, courses of instruction were offered at Harvard in a variety of topics including numerical analysis, switching theory, computer hardware, and automatic data processing," wrote Gerard Salton, a former student. "In the areas of computer use and instruction, Harvard seemed to be ahead of anyone else by some ten years."
|—||Basma Hashmi, a Ph.D. student at Harvard SEAS. She is the lead author of a new paper on engineering artificial teeth.|
Jelani Nelson, Assistant Professor of Computer Science and an expert in algorithms for big data analysis, has been selected to receive the prestigious NSF CAREER Award!
Super-Sound Detector Picks Up Silence, Makes It Roar
CAMBRIDGE, Mass., Jan. 15., 1934 — The fact that a suit of clothes creaks with every movement of the body is revealed by a super-sound detector at the Harvard university physics laboratory.
When this supersonic listener is turned on in a room perfectly quiet to the ear, the air is filled with noises. They are supersounds, air waves vibrating at 20,000 or more a second, too high to be audible to the human ear.
The noises arise apparently from every kind of motion, however slight. Among these supersounds the creaking of a good suit of clothes is among the noisiest. Stand in front of the mechanical listener and slowly bend one elbow. “Grrump,” goes the racket of the flaxlug fabric and keeps up this sound as long as the arm is in motion. Light a match, and above the soft flare which is audible to the ear the supersonic instrument picks up another noise resembling the distant rumble of a street car. Rubbing the palms of the hands together emits a stream of these sounds. Tearing a piece of paper sounds like far-off machine gun fire.
A roomful of men trying to remain entirely quiet registers on the supersonic device like the noises of a herd of elephants. This detector, designed by Dr. G. W. Pierce, Rumford professor of physics, is part of an extensive investigation of supersounds. In the air these inaudible waves travel farther than ordinary sounds. They also are transmitted by the other substances which carry sound, suggesting possible normal uses for signalling. In water they can be heard nearly 10 miles.
Music can be transmitted over a specially arranged supersound beam. For this Dr. Pierce uses the inaudible sound of a Gallon whistle, which sends out vibrations at the rate of about 25,000 a second. When the listening device is turned to the whistle it makes a high, clear note. But when a phonograph record is connected electrically with the whistle, the clear note modulates to carry faithfully every variation in sound of a full orchestra. These modulations are all in supersound frequencies, so that the music cannot be heard except when the listening device is cut in to receive the whistle and reduce its high frequencies to the audible range.
—The Bee, Danville, VA, 1934
Show us your pearly whites! This engineered “shrinking gel” prompts tooth tissue formation.
(Images courtesy of Basma Hashmi, Harvard SEAS.)
Harvard physicists have proposed a device to capture energy from Earth’s infrared emissions to outer space—a possible new source of renewable energy. Their analysis of the thermodynamics, practical concerns, and technological requirements will be published this week in PNAS.
“The key is in these beautiful circuit diagrams,” says Prof. Federico Capasso. “We found they had been considered before for another application… and been completely buried in the literature and forgotten. But to try to explain them qualitatively took a lot of effort.”
(Images courtesy of Eliza Grinnell; Steven J. Byrnes; and Federico Capasso and PNAS.)
|—||Eleanor Fort, Explore Careers in Energy & Environment panelist, Associate for State and Federal Climate and Energy Policy Program, CERES. Read the full story. (via ocsharvard)|
A sneak peek inside Harvard’s machine shop! Students learn welding, precision milling, 3D printing and more—all part of a hands-on engineering education. Learn more.