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Friability (pronounced , ""), the condition of being friable, describes the ability of a solid substance to be reduced to smaller pieces with little effort, especially by rubbing. The opposite of friable is indurate. Substances designated as being hazardous, such as asbestos or crystalline silica are often referred to as being friable if they are present in such a state that small particles easily can become dislodged, thus enabling them to become respirable (able to enter human lungs), posing a health hazard. Tougher substances, such as concrete, may also be mechanically ground down and reduced to finely divided mineral dust. However, such substances are not generally considered friable because of the degree of difficulty involved in breaking the substance's chemical bonds through mechanical means. Some substances, such as polyurethane foams, show an increase in friability with exposure to ultraviolet radiation as present in sunlight. Friable is sometimes used metaphorically to describe "brittle" personalities who can be "rubbed" by seemingly-minor stimuli to produce extreme emotional responses.〔(【引用サイトリンク】title=The Common Parlance )〕 ==Examples== A friable substance is any substance that can be reduced to fibers or finer particles by the action of a small pressure or friction, such as rubbing or inadvertently brushing up against the substance. The term could also apply to any material that exhibits these properties, such as: * Ionically bound substances that are less than 1 kg/L in density * Clumps of dried clay * Chalk * Stone * Tablets * Crackers * Perlite * Mineral fibers * Polyurethane (foam) * Aerogel 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「friability」の詳細全文を読む スポンサード リンク
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