Skip to main content Skip to Search Box
7 Topic Pages Found in Technology & Engineering and starting with the letter U
Details List
All A B C D E F G H I J K L M N O P Q R S T U V W X Z

study and application of the energy of sound waves vibrating at frequencies greater than 20,000 cycles per second, i.e., beyond the range of human

Open ultrasound

Pressure waves, known as ultrasonic waves, similar in nature to sound waves but occurring at frequencies above 20,000 Hz (cycles per second), the

Open Ulysses (Spacecraft)
Ulysses (Spacecraft)

Ulysses was the first space probe to explore the region of space above the Sun's poles, as a joint project of the European Space Agency (ESA) and

Unidentified Flying Object (UFO)

or UFO, an object or light reportedly seen in the sky whose appearance, trajectory, and general dynamic and luminescent behavior do not readily

Union Pacific Railroad

transportation company chartered (1862) by Congress to build part of the nation's first transcontinental railroad line. Under terms of the Pacific

United States national missile defense

System for which planning began in the United States in the 1960s to guard against a nuclear attack. The concept of missile defense is a product of

User Interface

In computing, the procedures and methods through which the user operates a program. These might include menus , input forms, error messages, and