domingo, 27 de março de 2011
sexta-feira, 18 de março de 2011
FAST FACTS ABOUT RADIATION FROM THE FUKUSHIMA DAIICHI REACTORS
Elevated radiation levels have been detected at and around the stricken nuclear power station in Japan, but the Chernobyl accident remains far more catastrophic
| March 16, 2011 | 11
The Japan Earthquake and TsunamiOn March 11, a powerful, magnitude 9.0 quake hit northeastern Japan, triggering a tsunami with 10-meter-high waves that reached the U.S. west coast. Here's the science behind the disaster »March 11, 2011
Image: WIKIMEDIA COMMONSSince a magnitude 9.0 earthquake rocked Japan and set loose a massive tsunami March 11, the Tokyo Electric Power Co. (TEPCO) has been scrambling to avert a nuclear disaster at its hardest hit plant. The Fukushima Daiichi nuclear power station, home to six nuclear reactors, has witnessedexplosions at three reactors and a fire in a spent-fuel pool at a fourth. At two reactors, unit Nos. 2 and 3, the vessels containing the nuclear material are suspected to be compromised.
A handful of plant workers remain on the site, implementing emergency cooling measures at the stricken, overheating reactors. Radiation levels have fluctuated wildly during the crisis, and the extent to which the workers' health has been endangered may not become apparent for years. But so far, the radiation releases have been limited compared with the 1986 Chernobyl disaster in Ukraine, an explosive event that caused dozens of cases of fatal radiation poisoning among plant workers and that has been implicated in thousands of thyroid cancer diagnoses in the years that followed. (Nuclear fission of uranium fuel produces radioactive iodine, which gathers in the thyroid gland.) As many nuclear experts have noted, the Fukushima reactors are better designed than the failed Chernobyl reactor.
Below are some facts and figures about the radiation hazard posed by the Fukushima breakdown and how it compares with other nuclear accidents in history. Many of the figures are measured in millisieverts, an international unit of radiation dosage. (One sievert is equal to 100 rems, which is a dosage unit of x-ray and gamma-ray radiation exposure; one millisievert is 0.1 rem.)
Radiation dose at the boundary of the Fukushima Daiichi nuclear power station on March 16: 1.9 millisieverts (mSv) per hour
Peak radiation dose measured inside Fukushima Daiichi on March 15:400 mSv per hour
Maximum allowable exposure for U.S. radiation workers: 50 mSv per year
Average exposure of U.S. residents from natural and man-made radiation sources: 6.2 mSv per year
Estimated total exposure at the boundary of the Three Mile Island site in Pennsylvania during the 1979 accident there: one mSv or less
Average total radiation dose to the 114,500 individuals evacuated during the 1986 Chernobyl disaster: 31 mSv
Half-life of iodine 131, a dangerous radioactive isotope released in nuclear accidents: eight days
Half-life of cesium 137, another major radionuclide released in nuclear accidents: 30 years
Decay products of iodine 131 and cesium 137: both emit gamma rays and beta particles (electrons or positrons)
Amount of nuclear fuel in Chernobyl reactor No. 4 that exploded in 1986:190 metric tons
Amount of nuclear fuel and fission by-products released into the atmosphere during Chernobyl disaster: 25 to 57 metric tons
Approximate amount of nuclear fuel in each crippled Fukushima Daiichi reactor: 70 to 100 metric tons
Sources: Japan Atomic Industrial Forum, International Atomic Energy Agency, U.S. Nuclear Regulatory Commission, National Council on Radiation Protection and Measurements, U.S. Environmental Protection Agency, United Nations Scientific Committee on the Effects of Atomic Radiation, National Institute of Standards and Technology, Nuclear Energy Institute
A handful of plant workers remain on the site, implementing emergency cooling measures at the stricken, overheating reactors. Radiation levels have fluctuated wildly during the crisis, and the extent to which the workers' health has been endangered may not become apparent for years. But so far, the radiation releases have been limited compared with the 1986 Chernobyl disaster in Ukraine, an explosive event that caused dozens of cases of fatal radiation poisoning among plant workers and that has been implicated in thousands of thyroid cancer diagnoses in the years that followed. (Nuclear fission of uranium fuel produces radioactive iodine, which gathers in the thyroid gland.) As many nuclear experts have noted, the Fukushima reactors are better designed than the failed Chernobyl reactor.
Below are some facts and figures about the radiation hazard posed by the Fukushima breakdown and how it compares with other nuclear accidents in history. Many of the figures are measured in millisieverts, an international unit of radiation dosage. (One sievert is equal to 100 rems, which is a dosage unit of x-ray and gamma-ray radiation exposure; one millisievert is 0.1 rem.)
Radiation dose at the boundary of the Fukushima Daiichi nuclear power station on March 16: 1.9 millisieverts (mSv) per hour
Peak radiation dose measured inside Fukushima Daiichi on March 15:400 mSv per hour
Maximum allowable exposure for U.S. radiation workers: 50 mSv per year
Average exposure of U.S. residents from natural and man-made radiation sources: 6.2 mSv per year
Estimated total exposure at the boundary of the Three Mile Island site in Pennsylvania during the 1979 accident there: one mSv or less
Average total radiation dose to the 114,500 individuals evacuated during the 1986 Chernobyl disaster: 31 mSv
Half-life of iodine 131, a dangerous radioactive isotope released in nuclear accidents: eight days
Half-life of cesium 137, another major radionuclide released in nuclear accidents: 30 years
Decay products of iodine 131 and cesium 137: both emit gamma rays and beta particles (electrons or positrons)
Amount of nuclear fuel in Chernobyl reactor No. 4 that exploded in 1986:190 metric tons
Amount of nuclear fuel and fission by-products released into the atmosphere during Chernobyl disaster: 25 to 57 metric tons
Approximate amount of nuclear fuel in each crippled Fukushima Daiichi reactor: 70 to 100 metric tons
Sources: Japan Atomic Industrial Forum, International Atomic Energy Agency, U.S. Nuclear Regulatory Commission, National Council on Radiation Protection and Measurements, U.S. Environmental Protection Agency, United Nations Scientific Committee on the Effects of Atomic Radiation, National Institute of Standards and Technology, Nuclear Energy Institute
terça-feira, 15 de fevereiro de 2011
COSAN
A Cosan, maior grupo de açúcar e etanol do Brasil, fechou trimestre passado com lucro líquido de R$ 27,9 milhões, queda de 83,3% em relação ao mesmo período do ano anterior, conforme dados divulgados na noite de quarta-feira.
No acumulado do ano fiscal, correspondente à safra 2010/2011 no Centro-Sul do país, o grupo sucroalcooleiro contabiliza ganho líquido de R$ 476,3 milhões, volume 29,7% menor na comparação anual.A companhia atribuiu a forte queda nos resultados, principalmente, ao aumento de custos "pelos reflexos advindos da quebra de safra verificada e pelos reflexos cumulativos do preço do ATR, além de maior originação de açúcar para revenda, com menores margens de contribuição unitária".
Já o Ebitda (sigla em inglês para lucro antes de juros, impostos, depreciação e amortização) da empresa totalizou R$ 410,5 milhões no terceiro trimestre fiscal, encerrado em 31 de dezembro, 16,3% inferior ao registrado em igual intervalo do ano anterior. No ano, o Ebitda acumulado é de R$ 1,57 bilhão.
A Cosan já havia informado no final de janeiro que a receita líquida no terceiro trimestre fiscal havia atingido R$ 4,74 bilhões, crescimento anual de 25%.
As vendas de açúcar da companhia somaram R$ 931,9 milhões no período, contra R$ 735,6 milhões em igual intervalo do ano anterior.
Enquanto isso, as vendas de etanol atingiram R$ 647,7 milhões, quase o dobro dos R$ 338,3 milhões obtidos no terceiro trimestre fiscal de um ano antes.
A empresa informou ainda que encerrou dezembro com dívida líquida de R$ 5,3 bilhões, sendo que os recursos em caixa somavam R$ 1,1 bilhão.
Veja a matéria original aqui.
sábado, 12 de fevereiro de 2011
ALSTOM SEALS $686M DEAL TO SUPPLY EQUIPMENT FOR BELO MONTE
Alstom has signed a contract worth about €500m ($686m) with Norte Energia of Brazil to provide power equipment for the 11GW Belo Monte Dam.
The French group will lead a consortium that includes Germany’sVoith and Austria’s Andritz to provide 14 611MW Francis turbine-generator sets and six smaller Bulb units. Alstom will supply seven Francis units, hydro-mechanical equipment and associated gas-insulated substations for the 14 units.
It is expected that Belo Monte will take eight years to build. When operating at full capacity, the dam will meet the electricity needs of 35 million people.
Alstom has played a significant role in the growth of Brazil’s hydro capacity, providing products and services for projects including Itaipu — the world’s second-largest plant — Tucuruí and, most recently, Jirau and Santo Antônio.
It has supplied more than 100 turbines and generators to the Brazilian market over the past ten years, and its equipment accounts for 35% of Brazil’s installed hydro capacity.
“Alstom’s world-leading power technology continues to play an important role in Brazil’s long-term quest to secure its energy future by investing in renewables,” says Alstom Power president Philippe Joubert. “This contract is the product of our commitment to developing highly efficient renewable-energy solutions. Our high-performance hydro turbines and generators, in conjunction with our grid technology, maximise the efficiency of hydropower plants.”
Published: Wednesday, February 9 2011 | Last updated: Thursday, February 10 2011
sexta-feira, 11 de fevereiro de 2011
AMADURECIMENTO DE FRUTAS
No 22º minuto, uma boa explicação sobre a ação do etileno no amadurecimento de frutas, assunto que sempre é tratado no Ivaporunduva...
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