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The Lower Paleolithic period lasted over 3 million years, during which there many human-like species evolved including toward the end of this period, Homo sapiens.The original divergence between humans and chimpanzees occurred 13 (), however interbreeding continued until as recently as 4 Ma, with the first species clearly belonging to the human (and not chimpanzee) lineage being ...
PVC is often used as the insulating sheath on electrical cables. PVC is chosen because of its good electrical insulation, ease of extrusion, and resistance to burn. [40] In a fire, PVC can form hydrogen chloride fumes; the chlorine serves to scavenge free radicals, making PVC-coated wires fire retardant.
The modern-day provisions of the law applied to inventions are laid out in Title 35 of the United States Code (Ch. 950, sec. 1, 66 Stat. 792). From 1836 to 2011, the United States Patent and Trademark Office (USPTO) has granted a total of 7,861,317 patents [7] relating to several well-known inventions appearing throughout the timeline below.
From the first Apple computer to the COVID-19 vaccine, here are the most revolutionary inventions that were born in the U.S.A. in the past half-century.
Beaux-Arts architecture: a 19th century architectural style drawing upon principles of French neoclassicism, and taking inspiration from the baroque and rococo styles. Impressionism: a 19th-century art movement originating with Parisian artists. Vaudeville: a theatrical genre of variety entertainment born in France at the end of the 19th century.
3rd century BC: Archimedes uses the method of exhaustion to construct a strict inequality bounding the value of π within an interval of 0.002. 3rd century BC: Archimedes develops the field of statics, introducing notions such as the center of gravity, mechanical equilibrium, the study of levers, and hydrostatics.
The electric flash-lamp is a device that uses an electrical circuit to trigger a fuse to ignite explosive powder such as magnesium, for a brief sudden burst of bright light "flash" from a chemical reaction of flash powder burning. It was principally used for flash photography in the early 20th century, but had other uses as well.
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