협성엔지니어링 협성엔지니어링

• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and sulfuric acid. Depending on the manufacturing process, nitrocellulose is esterified to varying degrees. The process uses a mixture of nitric acid and sulfuric acid to convert cellulose into nitrocellulose. In 1846, nitrated cellulose was found to be soluble in ether and alcohol. The glucose repeat unit (anhydroglucose) within the cellulose chain has three OH groups, each of which can form a nitrate ester. In precise chemical terms, nitrocellulose is not a nitro compound, but a nitrate ester. In terms of lacquers and coatings, nitrocellulose dissolves readily in organic solvents, which upon evaporation leave a colorless, transparent, flexible film. The overarching consequence is that the nitrocellulose is soluble in organic solvents such as acetone and esters; e.g., ethyl acetate, methyl acetate, ethyl carbonate. Nitrocellulose is widely used as support in diagnostic tests where antigen-antibody binding occurs; e.g., pregnancy tests, U-albumin tests, and CRP tests. In 1851, Frederick Scott Archer invented the wet collodion process as a replacement for albumen in early photographic emulsions, binding light-sensitive silver halides to a glass plate.

When Were Billiard Balls Invented? Further up the table is the pink ball, which sits midway between the blue spot and the top cushion, followed by the red balls (one each), placed in a tightly-packed triangle behind the pink. Finally, the black ball is placed on a spot 12.75 inches from the top cushion on a full-size table. If there is no available spot, it is placed as close to its own spot as possible in a direct line between that spot and the top (black end) cushion, without touching another ball. Your opponent gains the advantage of ball in hand, what is billiards entitling them to place the cue ball anywhere on the table before taking their shot. I talked to Rachel about the shot and she mentioned I didn’t think of my other option - to bank the 8. It was an eye opening moment! I think I won’t run that journal any more. Around 1846 Christian Friedrich Schönbein, a German-Swiss chemist, discovered a more practical formulation. A few years later in 1838, another French chemist, Théophile-Jules Pelouze (teacher of Ascanio Sobrero and Alfred Nobel), treated paper and cardboard in the same way.

Magicians' flash paper are sheets of paper consisting of pure nitrocellulose, which burn almost instantly with a bright flash, leaving no ash or smoke. A nitrocellulose slide, nitrocellulose membrane, or nitrocellulose paper is a sticky membrane used for immobilizing nucleic acids in southern blots and northern blots. Nitrocellulose lacquers have been used as a finish on furniture and musical instruments. Most lacquers are prepared from the dinitrate, whereas explosives are mainly the trinitrate. The principal uses of cellulose nitrate is for the production of lacquers and coatings, explosives, and celluloid. The yields are about 85%, with losses attributed to complete oxidation of the cellulose to oxalic acid. As he was working in the kitchen of his home in Basel, he spilled a mixture of nitric acid (HNO3) and sulfuric acid (H2SO4) on the kitchen table. Thus, nitrocellulose can denote mononitrocellulose, dinitrocellulose, and trinitrocellulose, or a mixture thereof. If you don't want to talk yourself you can be as dumb as a drum with a hole in it, as Sam Weller says, and you may go farther, and forbid anybody to speak to you; but to stamp and swear because somebody within hearing distance of you chooses to talk to a friend is ridiculous and silly, partly because it is contemptible, and partly because, as you are not in a position to stop all conversation on the links, you must grin and bear it.

For some reason which it is impossible to explain, golfers always seem to be far more frightened at being two yards beyond the hole than they are at being two yards short. Coloured ball racking positions must be remembered with care, as each time a coloured ball is potted, it is immediately replaced to its starting position, which occurs multiple times per frame, whereas reds are not returned to the table's surface after being potted. In UK eight-ball this would normally give the opponent the option of one of two plays: (1) ball-in-hand with two shots; (2) being allowed to contact, or even pot, a ball other than one from their set from the snookered position (although the black may not be potted), with the loss of the first shot. She's running out and gets really bad on the 8, but she didn't have a choice because of bad shape from the 7ball, but she just nails the long shot on the 8 ball! If there is no room this side of the spot, it will be placed as close to the spot as possible in a straight line towards the bottom cushion, without touching another ball.