John Vincent Atanasoff conceived basic design principles for the first electronic-digital computer in the winter of 1937 and, assisted by his graduate student, Clifford E. Berry, constructed a prototype here in October 1939. It used binary numbers, direct logic for calculation, and a regenerative memory. It embodied concepts that would be central to the future development of computers.
1930-1939
The total length of the Columbia-Wrightsville Bridge is 7,374 feet. Its construction required 100,000 cubic yards of concrete and 8 million pounds of steel reinforcing rods.
Parker DamState: CACountry: USAWebsite: http://www.asce.org/Project/Colorado-River-Aqueduct/Creator: Weymouth, Frank E.
Stretching 242 miles from the Colorado River on the California-Arizona border to its final holding reservoir near Riverside, California, the Colorado River Aqueduct consists of more than 90 miles of tunnels, nearly 55 miles of cut-and-cover conduit, almost 30 miles of siphons, and five pumping stations. Supplying approximately 1.2 million acre-feet of water a year - more than a billion gallons a day - it helped make possible the phenomenal growth of Los Angeles, San Diego, and surrounding Southern California areas in the second half of the 20th century.
The longest steel-arch bridge in the world for 46 years, the Bayonne Bridge continues to be celebrated today as a major aesthetic and technical achievement. The 1,675-foot bridge replaced a ferry service which until then was the only means of crossing from the Bayonne peninsula to Staten Island. While providing this essential link in the transportation network of greater New York City, the bridge's mid-span clearance of 150 feet also allows for unobstructed navigation on Newark Bay, the main shipping channel to the inland ports of Newark and Elizabeth, New Jersey.
The Bonneville Dam, Columbia River Power and Navigation System consists of 55 major projects on Oregon's Columbia River and is said to be the largest hydroelectric system in the world.
The Columbia River forms part of the border between Washington and Oregon and flows inland through the only waterway that crosses the Cascade Mountains. To harness the energy of the ninth longest river in North America, engineers developed unique design and construction approaches to overcome problems caused by depth of water, current velocity, and an irregularly-shaped river bottom.
"An essential part of the human experience is to create an aesthetic atmosphere."
The George Washington Bridge represented a departure in suspension bridge design. Chief Engineer O.H. Ammann developed a system of stiffening trusses that offered greater flexibility and saved the project nearly $10 million. Initially, just six of the upper eight lanes were paved, but Ammann designed the bridge to easily accommodate a future lower level.
Swiss-born O.H. Ammann (1879-1965) was Chief Engineer for the Port Authority of New York and New Jersey during the bridge's construction.
America's first practical helicopter, it pioneered the single main rotor concept that became the predominant helicopter configuration throughout the world. The principles that were developed and demonstrated by the VS-300 had direct application in the design of the early mass-production helicopter, marking the beginning of the world's rotorcraft industry.
The initial flight of the VS-300 was piloted by its designer, Igor I. Sikorsky (1889-1972), on September 14, 1939, in Stratford, Connecticut.