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はてなキーワード: pipesとは
結論：大丈夫。
MvK2010
I'm going to copy paste a full blog post of a research scientist at MIT here, who explains the situation at Fukushima much better than anyone else has, his message: no worries.
This post is by Dr Josef Oehmen, a research scientist at MIT, in Boston.
He is a PhD Scientist, whose father has extensive experience in Germany’s nuclear industry. I asked him to write this information to my family in Australia, who were being made sick with worry by the media reports coming from Japan. I am republishing it with his permission.
It is a few hours old, so if any information is out of date, blame me for the delay in getting it published.
This is his text in full and unedited. It is very long, so get comfy.
I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
There was and will *not* be any significant release of radioactivity.
By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.
I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.
We will have to cover some fundamentals, before we get into what is going on.
Construction of the Fukushima nuclear power plants
The plants at Fukushima are so called Boiling Water Reactors, or BWR for short. Boiling Water Reactors are similar to a pressure cooker. The nuclear fuel heats water, the water boils and creates steam, the steam then drives turbines that create the electricity, and the steam is then cooled and condensed back to water, and the water send back to be heated by the nuclear fuel. The pressure cooker operates at about 250 °C.
The nuclear fuel is uranium oxide. Uranium oxide is a ceramic with a very high melting point of about 3000 °C. The fuel is manufactured in pellets (think little cylinders the size of Lego bricks). Those pieces are then put into a long tube made of Zircaloy with a melting point of 2200 °C, and sealed tight. The assembly is called a fuel rod. These fuel rods are then put together to form larger packages, and a number of these packages are then put into the reactor. All these packages together are referred to as “the core”.
The Zircaloy casing is the first containment. It separates the radioactive fuel from the rest of the world.
The core is then placed in the “pressure vessels”. That is the pressure cooker we talked about before. The pressure vessels is the second containment. This is one sturdy piece of a pot, designed to safely contain the core for temperatures several hundred °C. That covers the scenarios where cooling can be restored at some point.
The entire “hardware” of the nuclear reactor – the pressure vessel and all pipes, pumps, coolant (water) reserves, are then encased in the third containment. The third containment is a hermetically (air tight) sealed, very thick bubble of the strongest steel. The third containment is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. For that purpose, a large and thick concrete basin is cast under the pressure vessel (the second containment), which is filled with graphite, all inside the third containment. This is the so-called “core catcher”. If the core melts and the pressure vessel bursts (and eventually melts), it will catch the molten fuel and everything else. It is built in such a way that the nuclear fuel will be spread out, so it can cool down.
This third containment is then surrounded by the reactor building. The reactor building is an outer shell that is supposed to keep the weather out, but nothing in. (this is the part that was damaged in the explosion, but more to that later).
Fundamentals of nuclear reactions
The uranium fuel generates heat by nuclear fission. Big uranium atoms are split into smaller atoms. That generates heat plus neutrons (one of the particles that forms an atom). When the neutron hits another uranium atom, that splits, generating more neutrons and so on. That is called the nuclear chain reaction.
Now, just packing a lot of fuel rods next to each other would quickly lead to overheating and after about 45 minutes to a melting of the fuel rods. It is worth mentioning at this point that the nuclear fuel in a reactor can *never* cause a nuclear explosion the type of a nuclear bomb. Building a nuclear bomb is actually quite difficult (ask Iran). In Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all containments, propelling molten core material into the environment (a “dirty bomb”). Why that did not and will not happen in Japan, further below.
In order to control the nuclear chain reaction, the reactor operators use so-called “moderator rods”. The moderator rods absorb the neutrons and kill the chain reaction instantaneously. A nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods. The coolant water then takes away the heat (and converts it into steam and electricity) at the same rate as the core produces it. And you have a lot of leeway around the standard operating point of 250°C.
The challenge is that after inserting the rods and stopping the chain reaction, the core still keeps producing heat. The uranium “stopped” the chain reaction. But a number of intermediate radioactive elements are created by the uranium during its fission process, most notably Cesium and Iodine isotopes, i.e. radioactive versions of these elements that will eventually split up into smaller atoms and not be radioactive anymore. Those elements keep decaying and producing heat. Because they are not regenerated any longer from the uranium (the uranium stopped decaying after the moderator rods were put in), they get less and less, and so the core cools down over a matter of days, until those intermediate radioactive elements are used up.
This residual heat is causing the headaches right now.
So the first “type” of radioactive material is the uranium in the fuel rods, plus the intermediate radioactive elements that the uranium splits into, also inside the fuel rod (Cesium and Iodine).
There is a second type of radioactive material created, outside the fuel rods. The big main difference up front: Those radioactive materials have a very short half-life, that means that they decay very fast and split into non-radioactive materials. By fast I mean seconds. So if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all. Why? By the time you spelled “R-A-D-I-O-N-U-C-L-I-D-E”, they will be harmless, because they will have split up into non radioactive elements. Those radioactive elements are N-16, the radioactive isotope (or version) of nitrogen (air). The others are noble gases such as Xenon. But where do they come from? When the uranium splits, it generates a neutron (see above). Most of these neutrons will hit other uranium atoms and keep the nuclear chain reaction going. But some will leave the fuel rod and hit the water molecules, or the air that is in the water. Then, a non-radioactive element can “capture” the neutron. It becomes radioactive. As described above, it will quickly (seconds) get rid again of the neutron to return to its former beautiful self.
This second “type” of radiation is very important when we talk about the radioactivity being released into the environment later on.
I will try to summarize the main facts. The earthquake that hit Japan was 7 times more powerful than the worst earthquake the nuclear power plant was built for (the Richter scale works logarithmically; the difference between the 8.2 that the plants were built for and the 8.9 that happened is 7 times, not 0.7). So the first hooray for Japanese engineering, everything held up.
When the earthquake hit with 8.9, the nuclear reactors all went into automatic shutdown. Within seconds after the earthquake started, the moderator rods had been inserted into the core and nuclear chain reaction of the uranium stopped. Now, the cooling system has to carry away the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions.
The earthquake destroyed the external power supply of the nuclear reactor. That is one of the most serious accidents for a nuclear power plant, and accordingly, a “plant black out” receives a lot of attention when designing backup systems. The power is needed to keep the coolant pumps working. Since the power plant had been shut down, it cannot produce any electricity by itself any more.
Things were going well for an hour. One set of multiple sets of emergency Diesel power generators kicked in and provided the electricity that was needed. Then the Tsunami came, much bigger than people had expected when building the power plant (see above, factor 7). The tsunami took out all multiple sets of backup Diesel generators.
When designing a nuclear power plant, engineers follow a philosophy called “Defense of Depth”. That means that you first build everything to withstand the worst catastrophe you can imagine, and then design the plant in such a way that it can still handle one system failure (that you thought could never happen) after the other. A tsunami taking out all backup power in one swift strike is such a scenario. The last line of defense is putting everything into the third containment (see above), that will keep everything, whatever the mess, moderator rods in our out, core molten or not, inside the reactor.
http://anond.hatelabo.jp/20110314030613
へ続く
Yahoo!Pipesってたまに見るけど何に使えるのか分からんという人のために自分がどのような用途に使っているか紹介します。
たぶんもっと使いこなしている人もいるとは思うけど自分のスキルだとこれが限界です。
公開されているパイプはそのまま使えますし、つぎはぎすれば自作も簡単にできます。
これは王道。題名にAD,PRとついているフィードを除去できます。
ちなみにちょっと正規表現を書くと記事内のアフィリエイトリンクも消せます。
大量に記事が配信されるフィードから特定のキーワードで抽出することができます。
例えば「Wikipedia日本語版-最近の更新」は1日に1000以上の記事が配信されるわけですが、その中で「Google」が含まれる記事のみを抽出して読むことができます。
Googleアラートみたいな使い方。例えば「Google」をニュース検索、ブログ検索、Twitter検索した結果を一つのフィードにまとめて読めます。
Yahoo!PipesでGoogleブログ検索とニュース検索を一度にしてみようと思って作ってみた。
しかし、Googleブログ検索の検索結果RSSをYahoo!Pipesで取得しようとしても403 Forbiddenというエラーが出る。
Yahoo!Pipesからのアクセスを弾いているということだろうか。
Googleニュースのほうは大丈夫なのになんでだろう。
Yahoo! PipesでGoogleの検索結果をRSSで取得するPipeを作ってみた | Blog.Ikubon.com
http://blog.ikubon.com/?eid=854266
↑で作っているもので俺のやりたいことを実現していたけど全く理解できないので腹が立つ。
Y!pipesでもgoogle gearsでもできるとおもうけど。
いまみたところ、この時間帯ぐらいから、RSSに含まれる元増田の比率が低くなってきて、
現時点のRSSからだけ抽出すると、どうも元増田が２－３個みたいな感じになってつまんないね。
ということで、DB叩こうとしてるんだが、そうなると、Y!pipesでもgoogle gearsだとキツくね？
gearsの方はできるのか？正直、手元のDBでRSSを再度はいてGearsに渡した方がかんたんじゃねーか？
どうなんだろう？
いま、データを抽出した後のをDB積んでる。Cronかけて５分に１度クロールするようにしてみた。
１時間ぐらい回してみる。
ついでに、表示しないデータ（レス）は、親の更新時刻も更新するようにはしたんだが・・・元までたどるには・・・
記事をクロールしてトラックバックから元を探すか、DBを連鎖して元までたどるしかないねぇ・・・
めんどくさい・・・
そんな感じ。
表示側はいじってないので、反映されないので注意。
titleと、content::encode中にhttp://anond.hatelabo.jp/を含まないこと
この条件ならY!pipesで出来そう。
本文はトラックバックツリーの様にクライアントサイドで取得する。
それとgoogle gearsを組み合わせたらどうかな？
Pipes: Rewire the webを使うと他人のサイトが簡単にスクレイピング出来てしまう。これまでスクレイピングするのにはほんのちょっとだけ技術的心理的障壁があった。今はそれすら要らない。loopとfetchだけわかればいい。広告を消すのも全文配信させるのも簡単に出来てしまう。
自前でplagger置いて加工するのはセーフ？
じゃあfeedreaderで読んでてgreasemonkeyで引っ張リ出すのは？
じゃあpipesは？
じゃあそれを公開するのは？
UTF-8ではないフィードを変換するのにwebサービスを使った。そのサービスが広告を差し込んでくるのは？
RSSに広告が差し込んであるのはウザい。それを消したものを公開するのは？
他人のフィードのアフィリエイトIDを全部自分のものに書き換えて公開するのは？
一度公開されてる情報だから好きにしていいだろ、これって通じるの？
出来てしまう事に逆らうべきではないという思考停止。
便利だからいいじゃないかという思考停止。
考えてもよくわからないから他人に丸投げして思考停止。
やってはいけないことのような気がするから触れないという思考停止。
フィードって何なのだろう。
webサイトって何なのだろう。
お金の臭いや作為の臭いがするとうわって思うけど判断基準はそれでいいの？それだけなの？
フィードで全文配信しないサイトは絶滅すればいいと思ってる。でもそれとこれとは話が別だ。
拒否するにはhttpd.conf(.htaccess)にUA書くかmeta tagに書くかpipesチームにメールを出せってこいつは何様なんだ？Pipes - Frequently Asked Questions
webサイトの書き手は、読み手は、いったいどこまで情報をコントロールする権利があるんだ？
サーバ型のFeed Readerが過去から未来までフィードを無限に全部蓄積して、すべて全文配信してくれれば一切余計なこと考えなくて済むのに。
とりあえずこれは読んだ。
ニュースのRSSを全文配信で読む - ytsuchiyamaの日記
最近perlの勉強してて、naoyaのはてなダイアリー - Web::ScraperでWeb::Scraperを知り、試しにはてブのAPIを真似してニフティクリップのコメントを吐くJSONを作った。
#!/usr/local/bin/perl -T # # use strict; use warnings; use URI; use Web::Scraper; use JSON::XS; use CGI; use Encode; my $q = new CGI; print $q->header( -type=>'text/plain', -charset=>'UTF-8'); my $path_info = $q->path_info; my $path = $path_info =~ m{^/?(nobracket/)?(http\w?)://?(.*)$}xms ? $2.'://'.$3 : undef ; exit if ! $path; my $is_nobracket = 'true' if $1; if ($q->query_string) { my $query_string = $q->query_string; $query_string =~ s/;/&/g; $path = $path.'?'.$query_string } $path =~ s/%23/#/; $path =~ s/([^\w ])/'%' . unpack('H2', $1)/eg; $path =~ tr/ /+/; my $entry_url = "http://clip.nifty.com/entry/?url=" . $path; my $bookmarks = scraper { process 'h4>a', 'user' => 'TEXT'; process 'li.dateAndTime', 'timestamp' => 'TEXT'; process 'a.tagtag', 'tags[]' => sub { my $text = $_->as_text or return; my $left = decode_utf8('??~P'); my $right = decode_utf8('??~Q'); return $text =~ /$left (.*?) $right/xms; }; process 'p.comment', 'comment' => 'TEXT'; result 'user', 'timestamp', 'tags', 'comment'; }; my $niftyclip_entry_info = scraper { process 'div.clipTitle>h3>a', 'title' => 'TEXT'; process 'div.clipTitle>p.url>a', 'url' => '@href'; process 'div.comments>div.commentsDetails', 'bookmarks[]' => $bookmarks; result 'title','url','bookmarks'; }; my $niftyclip = scraper { process 'div#content', 'niftyclip_entry' => $niftyclip_entry_info; result 'niftyclip_entry'; }->scrape(URI->new($entry_url)); exit if ! ($niftyclip->{'url'}); $niftyclip->{'entry_url'} = $entry_url; $niftyclip->{'count'} = @{$niftyclip->{'bookmarks'}}; my $json = JSON::XS->new->utf8->encode($niftyclip); $json = '('. $json. ')' if ! $is_nobracket; print $json;
取得方法は
http://monm.on.coocan.jp/niftyclip/json/entry/＜取得したいURL＞
ってすればいい。「#」は「%23」にエスケープしないとダメ。
作りながら「取得したいURLをURLエンコードするのは面倒だな」って思い、はてブのAPIみたいにpath_infoでアクセスできるようにしたわけだけど、その取得したいURLにquery_stringが付いてた場合にどうやってやって良いかわからず結構悩んだ。
結局、path_info+'&'+query_stringってやることで無理やり作ったけど、普通どうやるもんなんだろ？cpanに何か良いモジュールがあったりするのかな。
それと、はてブに合わせて出力の際に()を付けるようにしたけど、これだとYahoo!Pipesで使えなかったから、
http://monm.on.coocan.jp/niftyclip/json/entry/nobracket/＜取得したいURL＞
みたいに「nobracket」付きでアクセスした場合には()を付けないようにした。
コレ使うとニフティクリップとlivedoor クリプのコメント取ってくるAPIみたいなのが作れる。
RSSで取得する場合は
http://pipes.yahoo.com/pipes/pipe.run?_id=zECBJ_VY3BGtBw6B8ivLAg&_render=rss&URL=＜URLエンコードしたURL＞
で取得できるし、jsonで取得する場合は
http://pipes.yahoo.com/pipes/pipe.run?_id=zECBJ_VY3BGtBw6B8ivLAg&_render=json&URL=＜URLエンコードしたURL＞
ってなる。
とりあえずサクッと作ってみたけど、わざわざページからJSON作ってるからちょっと重い。
その頃にはJSON吐いてくれるようになるんじゃないかなと期待はしてるけど。
参考URL:
KEREM SHALOM, Israel, July 11 ?? Real life has a way of intruding into the airy absolutes of the Israeli-Palestinian conflict. Each side may deny the other’s historical legitimacy, or plot the other’s demise, but somehow, the gritty business of coexistence marches on.
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Rina Castelnuovo for The New York Times
An Israeli man signaled for a truck to move toward Gaza at Sufa on Wednesday. Commerce continues despite the Hamas takeover.
The New York Times
For the past month, since the Islamic militants of Hamas took over the Gaza Strip, Israel has kept the main commercial crossing point at Karni shuttered, squeezing the life out of the limp Gazan economy. Israel bans contact with Hamas, and Hamas seeks Israel’s destruction, making border crossing etiquette more precarious than elsewhere.
Yet at this small crossing near the Egyptian border on Wednesday, between mortar attacks by Hamas and other militants, about 20 truckloads of milk products, meat, medicines and eggs passed from Israel into Gaza, part of the effort to keep basic commodities reaching the 1.5 million Palestinians of the largely isolated strip. Most of the supplies are not humanitarian relief, but are ordered by Palestinian merchants from Israeli suppliers, relying on contacts built up over years.
The mechanics of the crossover manage to answer Israel’s security needs while avoiding contact with Hamas. At Kerem Shalom, Israeli trucks transfer their goods to what Israeli military officials describe as a “sterile” Palestinian truck. Driven by a carefully vetted Palestinian driver, the truck never leaves the terminal, carrying the goods to the Palestinian side, where they are transferred onto ordinary Palestinian trucks that drive into Gaza.
Kerem Shalom, which means “vineyard of peace,” is surrounded by fences and concrete barriers. It can process only about 20 trucks a day, so it is reserved for products that require refrigeration.
The hardier goods, which make up the bulk of the supplies, go through another crossing, at Sufa, to the north. About 100 Israeli trucks a day come from Israel, swirling up clouds of dust before dumping thousands of tons of dry products, bales of straw and crates of fruit on “the platform,” a fenced-in patch of baked earth. At 3 p.m. the Israeli suppliers leave. Like drug dealers picking up a “drop,” the Gaza merchants send in trucks from a gate on the other side and take the products away.
Other products make their way into Gaza with virtually no human interaction. At the fuel depot at Nahal Oz, Israeli tankers pour diesel, gasoline and cooking gas into Gaza through pipes that run beneath the border. And even at Karni, the main crossing that closed for normal operations on June 12, the Israelis have adapted a 650-foot-long conveyor belt, which was previously used for gravel, to send in grain.
“It is better all around from a security point of view that commodities go in,” said Maj. Peter Lerner of the Coordination and Liaison Administration, the Israeli military agency that deals with the civilian aspects of the Gaza border. “More despair doesn’t serve anyone.”
Israeli officials cite security reasons for having shut Karni, the only crossing equipped to send containers into Gaza, or to handle exports out of the strip. “Karni was based on the concept of two sides operating together,” said Col. Nir Press, the head of the coordination agency.
Colonel Press noted that in April 2006, a vehicle loaded with half a ton of explosives got through three of four checkpoints on the Palestinian side of Karni, and was stopped at the last security position by members of the American-backed Presidential Guard, loyal to the Palestinian president, Mahmoud Abbas of Fatah.
But the Presidential Guard is no longer there, having been routed, along with all other Fatah forces in Gaza, by Hamas.
Instead, the military wing of Hamas and other Palestinian factions have been firing mortar shells at Kerem Shalom. On Tuesday, 10 of them landed in and around the terminal as two trucks of milk were passing. The crossing was closed for the rest of the day. [Another barrage of mortar shells hit areas around Kerem Shalom on Thursday.]
Hamas suspects that Israel wants to use Kerem Shalom to replace the Rafah crossing on the Egypt-Gaza border, which has been closed since June 9. The Palestinians had symbolic control at Rafah. At Kerem Shalom, Israel can better supervise who ?? and what ?? is going in and out of the strip.
“Kerem Shalom is a military post, a place from which Israeli tanks begin their incursions into Gaza,” said Fawzi Barhoum, a Hamas spokesman, justifying the mortar attacks. “How can we consider it a safe and legitimate crossing to replace Rafah?”
But when it comes to food, rather than principle, Hamas is proving itself pragmatic as well. On Sunday, Palestinian merchants, trying to press Israel to reopen Karni, told the Israelis that Hamas had barred the import of Israeli fruit. But by Wednesday, the Israeli fruit was ordered again. “Hamas does not want to lose the private sector,” a Gaza businessman explained.
Tellingly, the exposed Sufa crossing, through which most of the food comes, has not been attacked with mortars so far. Without Karni, however, and with the smaller crossings operating on a one-way basis, Gaza can barely subsist. With hardly any raw materials going in, and no products from Gazan farms, greenhouses and factories so far allowed out, Gaza’s tiny industrial base is on the verge of collapse.
Hamas officials say they want to start negotiations with Israel about reopening the formal crossings. Major Lerner said that Hamas had “a few things to do” first, including recognizing Israel’s right to exist and freeing Gilad Shalit, the Israeli soldier captured and taken to Gaza in a raid more than a year ago.
But the ultimate test of pragmatism may come in September when the Hebrew calendar enters what is known in Jewish law as a “shmita” year. Then the fields of Israel are supposed to lie fallow, and observant Jews seek agricultural products grown elsewhere. Before the Hamas takeover, Israel’s rabbis had reached agreements with Palestinians to import vegetables from Gaza, Major Lerner said. Given the needs of both sides, it may still happen.