zinc-coated sheet
71Roof construction — This article is about house construction that consists of beams and an outer weatherproof skin, as found on most domestic architecture. Such roofs may take a number of different shapes. Construction of a ridged roofA simple ridged roof consists… …
72test — 1. To prove; to try a substance; to determine the chemical nature of a substance by means of reagents. 2. A method of examination, as to determine the presence or absence of a definite disease or of some substance in any of the fluids, tissues,… …
73Chromium — This article is about the chemical element. For other uses, see Chromium (disambiguation). vanadium ← chromium → manganese ↑ Cr ↓ Mo …
74Light-emitting diode — LED redirects here. For other uses, see LED (disambiguation). Light emitting diode Red, pure green and blue LEDs of the 5mm diffused type Type Passive, optoelectronic Working principle Electr …
75Titanium — This article is about the chemical element. For other uses, see Titanium (disambiguation). scandium ← titanium → vanadium …
76Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… …
77photography, history of — Introduction method of recording the image of an object through the action of light, or related radiation, on a light sensitive material. The word, derived from the Greek photos (“light”) and graphein (“to draw”), was first used in the… …
78Magnesium — Not to be confused with Manganese. sodium ← magnesium → aluminium Be ↑ Mg ↓ Ca …
79elastomer — elastomeric /i las teuh mer ik/, adj. /i las teuh meuhr/, n. Chem. an elastic substance occurring naturally, as natural rubber, or produced synthetically, as butyl rubber or neoprene. [1935 40; ELAST(IC) + O + Gk méros a part] * * * ▪ chemical… …
80offset printing — Lithog. offset (def. 6). * * * or offset lithography or litho offset In commercial printing, a widely used technique in which the inked image on a printing plate is imprinted on a rubber cylinder and then transferred (offset) to paper or other… …
