海量資源，盡在掌握
Therailroadsofthenearfuturewillprobablynotinvolveanyspectacularlynewprinciplebutwillbedevelopmentsofthoseweusetoday.Therailadministrationshavebuilttheirentiresystemtoastereotypedmodel,withtwosteelrailsofaparticulartypeseparatedbya“gauge”ofabout1.43m,1.07m...[繼續(xù)閱讀]
Aharborisanyplacethatprovidesseagoingshipsorboatsofanykindwithameasureofprotectionfromthewindandwaves.Tofulfillthisrole,aharbormustbedeepenoughtoaccommodatethelargestshipsthatmayuseit,andhaveabottomthatwillholdthematanchor.Aportisaharborwithfacilitiesfort...[繼續(xù)閱讀]
ModerncanalprovideimportanttransporthighwaysthroughoutEuropeand,toalesserextent,NorthAmerica.TheriversRhineandMosellefeedandxtensivecanalsysteminGermanythathasconnectionstotheDutch,Belgian,andFrenchnetworks.AnewmajorwaterwayiscompletedtoconnecttheRhinewit...[繼續(xù)閱讀]
Controlofhislife-sustainingwatersupplyhasalwaysbeenoneofman’sprimaryconcerns.For5,000years,damshavebeeninstrumentalinthiscontrol,beingusedtoavertfloods,divertrivers,storewater,andirrigateland.Manyoftoday’sconstructionsfulfillthesesameage-oldfunctions;dams...[繼續(xù)閱讀]
Themoreprosperousmanbecomes,themorewaterheuses.In1980sindevelopingcountries(theThirdWorld),somecommunitiesmanagewithanaverageof2.5gallons(12liters)ofwaterperpersonperday.InmostEuropeancitiesthedailydomesticconsumptionpercapitaofthepopulationisnearer33gall...[繼續(xù)閱讀]
Assoonasearlypeoplesestablishedsettlementtheyhadtheproblemofgettingridofsewage——theirorganicwastesand,sometimes,thoseofdomesticanimals.Naturedisposesofsurplusorganicmaterialinfourprincipalwaysbydilution,oxidation,putrefaction,andfiltration.Earlypeoplesrel...[繼續(xù)閱讀]
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