Cov txheej txheem:
- PCBs siv rau hnub no yog dab tsi?
- Peb puas tseem siv PCBs?
- Vim li cas PCBs tseem muaj teeb meem?
- PCBs nyob hauv ib puag ncig ntev npaum li cas?
Video: Puas yog pcbs tseem siv niaj hnub no?
2024 Tus sau: Fiona Howard | [email protected]. Kawg hloov kho: 2024-01-10 06:38
Vim lawv txoj kev ua neej ntev, PCBs tseem siv dav, txawm tias lawv cov khoom siv tau poob qis heev txij li xyoo 1960, thaum muaj teeb meem tshwm sim. … Raws li US Environmental Protection Agency (EPA), PCBs ua rau mob qog noj ntshav hauv cov tsiaj thiab yog tib neeg carcinogens.
PCBs siv rau hnub no yog dab tsi?
Kev lag luam siv rau PCBs
- Transformers thiab capacitor.
- Cov khoom siv hluav taws xob suav nrog cov tswj hluav taws xob, hloov pauv, rov kaw dua, bushings, thiab electromagnets.
- Cov roj siv hauv cov motors thiab hydraulic systems.
- Cov khoom siv hluav taws xob qub lossis cov khoom siv uas muaj PCB capacitors.
- fluorescent teeb ballasts.
- Cable rwb thaiv tsev.
Peb puas tseem siv PCBs?
PCBs tau siv dav hauv cov khoom siv hluav taws xob xws li capacitors thiab transformers. Lawv kuj tau siv hauv cov kua dej hydraulic, cov kua dej hloov hluav taws xob, cov roj nplua nyeem, thiab cov yas yas. … Xyoo 1979, US Environmental Protection Agency (USEPA) txwv tsis pub siv PCBs; Txawm li cas los xij, PCBs tseem muaj nyob hauv ntau cov khoom ua ntej xyoo 1979
Vim li cas PCBs tseem muaj teeb meem?
Txawm tias tsis siv, PCBs, lossis polychlorinated biphenyls, tseem muaj nyob hauv ib puag ncig niaj hnub no vim lawv tsis tawg sai sai Lub sijhawm uas nws siv tshuaj xws li PCBs kom tawg ib txwm nyob ntawm lawv qhov loj me, qauv, thiab tshuaj muaj pes tsawg leeg.
PCBs nyob hauv ib puag ncig ntev npaum li cas?
Lub sijhawm nws siv rau ib nrab ntawm cov PCBs (thaum pib) tam sim no kom tawg yog li ntawm 3.5 txog 83 hnub rau cov molecules nrog 1 txog 5 chlorine atoms. Hauv dej, PCBs yog qhov tseem ceeb tawg los ntawm lub hnub ci (photolysis).
Pom zoo:
Puas cov kwj dej tseem siv niaj hnub no?
kwj dej kuj yog siv thauj dej rau kev siv dej thiab lwm yam tib neeg siv. Txawm hais tias qhov tshwm sim ntawm cov qauv kev thauj mus los tau zoo dua tau txo qhov xav tau ntawm cov kwj dej, lawv tseem ua lub luag haujlwm tseem ceeb ua cov kav dej rau kev thauj mus los thiab txhawb kev lag luam thoob ntiaj teb .
Puas yog cov roman aqueducts tseem siv niaj hnub no?
Tseem muaj ib tug Roman aqueduct uas tseem ua hauj lwm thiab nqa dej mus rauib txhia ntawm Rome lub kwj dej. Lub Acqua Vergine, ua rau xyoo 19 BC, tau rov qab los ob peb zaug, tab sis nyob rau hauv cov dej ua haujlwm. Roman aqueduct ntawm Pont du Gard, hla tus dej Gard nyob rau sab qab teb Fabkis .
Peb puas tseem siv cuneiform niaj hnub no?
Thaum kawg, nws tau hloov pauv tag nrho los ntawm kev sau cov tsiaj ntawv (hauv qhov kev nkag siab dav dav) nyob rau hauv lub sijhawm Roman, thiab tsis muaj cov tshuab cuneiform hauv kev siv tam sim no. Nws yuav tsum tau txiav txim siab raws li kev sau ntawv tsis paub meej nyob rau xyoo 19th Assyriology .
Puas yog cov hlau nplaum tseem siv niaj hnub no?
Tsis muaj qhov kawg ntawm lub sijhawm ironclad, tab sis txog rau thaum xaus ntawm 1890s lub sij hawm ironclad poob tawm ntawm kev siv. Cov nkoj tshiab tau nce ntxiv rau tus qauv qauv thiab xaiv cov nkoj sib ntaus sib tua lossis cov tub rog caij nkoj .
Puas yog plows tseem siv niaj hnub no?
Hnub no, plows tsis siv ze li yav dhau los. Qhov no yog vim feem ntau rau qhov muaj koob meej ntawm qhov tsawg kawg nkaus tillage systems tsim los txo cov av yaig thiab txuag dej . Peb puas tseem siv plooj? Tom qab 4,000 xyoo lub plows tseem nyob nrog peb thiab nws txoj kev loj hlob tau qeeb thiab tsis tu ncua tab sis cov thev naus laus zis tau zoo ib yam.
