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nutrition

(Encyclopedia)nutrition, study of the materials that nourish an organism and of the manner in which the separate components are used for maintenance, repair, growth, and reproduction. Nutrition is achieved in vario...

ultrasonics

(Encyclopedia)ultrasonics, 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 hearing. The application of sound energy...

Mayer, Julius Robert von

(Encyclopedia)Mayer, Julius Robert von, 1814–78, German physician and physicist, studied medicine at Tübingen, Munich, and Paris. From a consideration of the generation of animal heat, he was led to determine th...

Szilard, Leo

(Encyclopedia)Szilard, Leo sĭˈlärd [key], 1898–1964, American nuclear physicist and biophysicist, born in Hungary. He was educated at the Budapest Institute of Technology and the Univ. of Berlin, receiving a d...

actin

(Encyclopedia)actin, a protein abundantly present in many cells, especially muscle cells, that significantly contributes to the cell's structure and motility. Actin can very quickly assemble into long polymer rods ...

electromagnet

(Encyclopedia)CE5 Electromagnet electromagnet, device in which magnetism is produced by an electric current. Any electric current produces a magnetic field, but the field near an ordinary straight conductor is ...

Draper, John William

(Encyclopedia)Draper, John William, 1811–82, American scientist, philosopher, and historian, b. near Liverpool, England, M.D. Univ. of Pennsylvania, 1836. In 1839 he became professor of chemistry at the Univ. of ...

Tsukuba

(Encyclopedia)Tsukuba tso͝oko͞oˈbä [key], city (1990 pop. 143,396) Ibaraki prefecture, central Honshu, E central Japan, 31 mi (50 km) S of Mito. The city's products include peanuts, mushrooms, tea, processed fo...

windmill

(Encyclopedia)windmill, apparatus that harnesses wind power for a variety of uses, e.g., pumping water, grinding corn, driving small sawmills, and driving electrical generators. Windmills were probably not known in...

solid waste

(Encyclopedia)solid waste, discarded materials other than fluids. In the United States in 1996, nearly 210 million tons—about 4.3 lb. (2 kg) per person daily (up from 2.7 lb./1.2 kg in 1960)—were collected and ...