简介:一块普通的玻璃很难引起人们的注意。倘若你将一块普通玻璃在火中加温,而且是逐步升温,直到炸裂、熔化,中途你可以浇上水,而后,你仔细观察,会发现过火玻璃有很多特点,这些特点很可能成为火调人员调查火灾原因的重要证据,我相信这些会引起你的兴趣,不妨试试,下面本文将就玻璃在火场中的特点来叙述其在火调中的作用。我们要想依据火场中的玻璃中查找火因证据、线索,就必须从玻璃破坏的痕迹入手,确切地说是在热作用下玻璃破坏的痕迹。l、玻璃的热变形普通平板玻璃主要由二氧化硅、氧化钙及少量的氧化钠、氧化铝等组成,它不象钢化玻璃、石英玻璃等选用特殊材料经过特殊工艺处理,因而质脆,弹性差,但在高温下可以软化。玻璃不象其他物质
简介:Cities,asthemostcomplexofhumancreations,areatgreatriskbothfromawiderangeofhazardsandfromtheirownmultiplevulnerabilities.Withthecurrentformofglobalization,citiesaroundtheworldaremovingtogetherintoanewandhazardousenvironment.Morecitieshavenowbecomestrategicandindependentlinchpinsintheglobaleconomy.Disrupteconomiclifeinanyonemajorcityandshockwavescircletheearthalmostinstantly.However,tosustainconsumerconfidencewhichunderliestheglobaleconomy,muchinformationthatmightgenerateseriousdoubtabouttheworld'sfuturehasnotbeentabledforgeneralpublicconsideration.Whilethenewhazardofglobalterrorismforcestherevealofthereality,globalistsarefacingseverechallengesincludingthepsychologicalimpact.Theauthordrawsananalogyoftheindustrializationin19thcenturyandproposesmanyofthechangesthatareneededtoreducethevulnerabilityofcities.