История - Помощь и ответы на домашние задания по истории - 148

Riddle solved: Why was Roman concrete so durable? An unexpected ancient manufacturing strategy may hold the key to designing concrete that lasts for millennia. January 6, 20231 David L. Chandler/MIT News Office The ancient Romans were masters of engineering, constructing vast networks of roads, aqueducts, ports and massive buildings, whose remains have survived for two millennia. Many of these structures were built with concrete: Rome's famed Pantheon, which has the world's largest unreinforeed concrete dome and was dedicated in 128 C.E , is still intact, and some ancient Roman aqueducts still deliver water to Rome today Meanwhile, many modern concrete structures have crumbled after a few decades. Researchers have spent decades trying to figure out the secret of this ultradurable ancient construction material, particularly in structures that endured especially harsh conditions, such as docks, sewers, and seawalls, or those constructed in seismically active locations Now,a team of investigators from MIT, Harvard University, and laboratories in Italy and Switzerland, has made progress in this field discovering ancient concrete -manufacturing strategies that incorporated several key self-healing functionalities. For many years, researchers have assumed that the key to the ancient concrete's durability was based on one ingredient: pozzolanic material such as volcanic ash from the area of Pozzuoli, on the Bay of Naples . This specific kind of ash was even shipped all across the vast Roman empire to be used in construction, and was described as a key ingredient for concrete in accounts by architects and historians at the time. Under closer examination, these ancient samples also contain small, distinctive, millimeter-scale bright white mineral features, which have been long recognized as a ubiquitous component of Roman concretes These white chunks, often referred to as "lime clasts," originate from lime, another key component of the ancient concrete mix. "Ever since I first began working with ancient Roman concrete , I've always been fascinated by these features," says MasiC. "These are not found in modern concrete formulations, so why are they present in these ancient materials?" Previously disregarded as merely evidence of sloppy mixing practices, or poor-quality raw materials, the new study suggests that these tiny lime clasts gave the concrete a previously unrecognized self-healing capability. "The idea that the presence of these lime clasts was simply attributed to low quality control always bothered me " says MasiC. "If the Romans put so much effort into making an outstanding construction material, following all of the detailed recipes that had been optimized over the course of many centuries, why would they put so little effort into ensuring the production of a well-mixed final product? There has to be more to this story."Upon further characterization of these lime clasts, using high-resolution multiscale imaging and chemical mapping techniques pioneered in Masic's research lab, the researchers gained new insights

Kowmponewon paboma no Bceobused ucmopuu B knoce. 1 sopuanm, 1. Hawue cobismen coorseccroyor XVill neny: 2. Yro rakoe Mopepusaaun (wanucarb onpegenenwe) 3. Ormerore 4 ocrobrbix yuacreonanunk no oppawuyackok penomo A) Ulapno-Tlyw ae Mokreckbe; B) MqH-flonb Mapar; f)Tomac AmedpepcoH; A) Makchumunah Pobecribep. E) HanoneoH boHanapt; M) OHope Ae MMpa6o. 4. Ha30BMre punocopos 3nox IlpocseujeHMA: A) Agam CMMT; 5) Hapup-ulax; B) ArkoH /lokk; T) K. Mapkc; A) #K-XK Pycco. 5. Kro 43 koponen QpaH4MM 6bin Ka3HeH nocne BenHKOM (ppanuyackozi pesoniounn? A) MrogoBMKX; 5) MrogoBHK XIV; B) MrogoBMKXV; r) JiogoBuk XVI. 6. Kakoe co6bime npowsouino 26 asrycra 1789 ropa? 7. 4ro rakoe bacrunun?B Kakon crpaHe owa Haxoawnacb HC YeM CBR3aHa? 8. C KaKKMM CO6bITHRM CBR3AHa CeBepHan BODHa?

3. PaGorHuk ynpanienng 3AO <Moz10Ko3aBoz "bezopeyse"Pollutin, TPY:IMBINNHCA COTTACHO TPY.IOBOMY 110TOBODY B pexKHMe HeHOPMHPOBAHHOTO pa6oqero IIHA, B Tevenme peBpa.18 HeCKOJIbKO pa3 TIPHBJeKa.TCA K paGore B monyuenun sapabornoi muanbu 3a (pespailb OH o6HapyXKH1, TTO yKa3aHHbIC IHH eMy He onjayeHbl. Jupekrop pa3bsiCHH,I Pountry, "TO 3a B pexKHMe HCHODMI LIHN EMY B COOTBeTCTBME I c 3aKOHOM npezocraBISETCH PaGOTHHK He corractincs C 21080:1aMH :ImpekTopa H penilui o6paTHTbCN B cya. Kakoe pewenue donorcen npunsmb cy)? Omeem o6ocHytime.

This writer founded Britain's first celebrity cricket team which incleded: H . G. Wells, Sir Arthur Conan Doyle, G. K . Chesterton , Jerome K. Jerome, P. G . Wodehouse , and A. A . Milne. square

B Kakux curyaun ax HYXKHO Mogenul oBaHue? Monenu o6bekTOB N npoueccoB noMoraloT npoBorlutb uccnenoBaHus n CTPOMTb nporH03bl. KaK Tbl Aymaeulb ,Ana yero B 3Tux npumepax ucrionb3yloT MogenupoBaHue (co3AaHuen uccnerioBa Hue Moneneu Ang n3yueHus opuruHana)? 3apawa: BblSCHMTb, noMoxer pacumpettue 3apava: noka3arb, Kak M3MeHMTCR ynu4a 4epea cro ner 3apawa: cnpor HO3MpoBarb nocneactens CTO/KHOBeHMR CaMonèra C AOMOM 3apawa: N3y4MTb nosegerme ynu4Hblx Koulek 3kcnepumeHT 3arpareH MOYeHb OnaceH MonenuposaHue He HyXHO Opurutana He cyujecr- Byer 3KcnepuMeHT OVEHb Aoporon

Помощь с домашним заданием по истории