Conservatives' Trust in Science at All-Time Low
A new study suggests a growing partisan divide as science plays an increasing role in policy debates.
| Posted Thursday, March 29, 2012, at 1:29 PM ETPhoto by Aude Guerrucci-Pool/Getty Images.
太陽能節能玻璃之研發及其在綠建築之應用
文‧圖/楊錦懷
地球暖化日趨嚴重,全球都在努力降低碳排放。建築耗能產生之溫室氣體更是其中之大宗,根據歐盟調查,建物之耗能約占全球各種民生耗能之40%,尤以製造傳 統電力所產生之二氧化碳與室內冷氣空調所產生之氫氟碳化物(HFCs)為兩大主要溫室氣體,因此最新之建築理念為讓建物本身可產生再生能源並降低建築耗 能,也就是說建物所須能源來自本身外殼之太陽能源,並同時降低空調耗能,達到電力自給自足,這才是降低地球暖化之具體展現。
三機一體
最新之建築理念為降低建築仰賴外來能源,轉向再生能源並降低建物耗能,達到電力自給自足。個人所主持之太陽能與節能建築研究團隊,獲教育部頂尖計畫補助, 成功研發出世界第一片結合自潔、隔熱與發電三機一體之太陽能玻璃。首先,此光電玻璃之外部表面塗佈奈米光觸媒,可分解表面污染物,住戶不必再為玻璃不易清 洗而煩惱。其次,還能有效隔絕太陽光產生之輻射熱,減少冷氣使用。且其紫外線穿透率為零,可保護室內之人員與傢俱不受紫外線傷害;紅外線穿透率亦為零,有 效隔絕室外熱源。加上還能發電,可大幅降低對臺電之供電需求。此研發之關鍵技術在於將“Off-module Power Enhanced”(高效率反射膜)之技術應用於光電模組,以最低之成本達到最高之發電效率,此技術目前可提升8%之發電效率,最大發電量為晴天正午 106 W/m2。因為有隔熱效能,所以屋內不會熱,節省冷氣之耗電,經實體屋試驗可節省40%之冷氣耗電,冬天亦有保暖作用,可省30%之暖房耗電。同時開源 (提升發電力)與節流(節省冷房空調),不僅兼顧環保與節能,某種程度還具備電力自足概念,已為綠建築注入新的應用元素。
此一技術深受日本光電產業重視,而有日本翠光株式會社與臺科大簽署技轉合約,並在2009年東京光電展中,榮獲最有潛力之太陽能產品。進而引起 Discovery頻道之注意,分別於2009年與2011年製播專輯報導。已實地應用在工程建築方面的,國外有馬來西亞之光電牌樓,國內有建研所EAG HOUSE,陽明山私人別墅,捷運大安森林公園站,2010臺北國際花博美國館與高雄龍興國小等。
研發理念
如前所述,本研發之關鍵技術在於應用高效率反射膜技術,用最低之成本達到最高之發電效率。我們利用光反射原理,將高反射率之隔熱膜置於透光光電模組後方, 使發電模組產生二次發電,以提升發電效率與同時達到隔熱功能。如圖1所示,在戶外太陽光照射下可提升8%之發電效率,同時更降低4倍之輻射熱,證明能強化 太陽能模組之電力並降低輻射熱之進入室內,同時增加再生能源與降低耗能,達到雙重效果。
圖1:太陽能節能玻璃可同時提升8%之發電效率與降低4倍之輻射熱穿透。
一、發電功能
如圖2所示,本光電玻璃之透光度10%時,在戶外量測之最高發電效率為106 W/m2。
圖2:研發之光電玻璃在戶外量測之最高發電效率為106 W/m2。
二、隔熱功能
如圖3所示,在監測屋驗證中,以所發明之太陽能節能玻璃所建造之監測屋與一般玻璃屋相較,太陽能節能玻璃屋有明顯之斷熱功能,尤其在夏天正中午時,一般玻璃屋室內溫度已高達40度,但太陽能節能玻璃屋之室內溫度僅為26度,有明顯之隔絕輻射熱之功能。
圖3:太陽能節能玻璃所建造之監測屋與一般玻璃屋隔熱功能相較。
如圖4所示,本光電玻璃在監測屋中進行冷房試驗,與10mm厚之傳統強化玻璃屋相較,傳統玻璃屋冷房耗電 3.29 度,而太陽能節能玻璃屋只耗電2度,顯見太陽能節能玻璃可降低冷房耗電之40%,有效達到節能。
圖4:太陽能節能玻璃測試屋進行冷房節能試驗。
如圖5所示,在本校頂樓之測試屋進行寒流來時之暖氣耗電比較,試驗從傍晚6點進行至次日清晨6點,共12小時,傳統玻璃測試屋之暖氣耗電為9.8度,而太陽能節能玻璃測試屋之暖氣耗電為6.9度,足見有相當之省暖房耗電效果,可以省下30%之暖氣耗電費,適用於寒帶國家。
圖5:在臺科大頂樓之測試屋進行寒流來時之暖氣耗電比較。
國際媒體報導
2008年11月5日 Discovery頻道至本校專訪太陽能節能玻璃,並於2009年10月開始在全世界各地以不同語言播出(圖6)。2011年6月19日《科技新亞洲第3 集》,介紹日本、韓國、臺灣、新加坡等國的先進發明時,本團隊「太陽能節能玻璃」也成為本集節目中的亮點。(圖7)。
圖6:Discovery於2008年專訪畫面一二。
圖7:Discovery《科技新亞洲》報導第二代太陽能節能玻璃。
實際應用
本技術於2008年發 表後,已技轉並陸續應用於多項工程,如表1與表2所示。其中新加坡之案例原為BCA新加坡建研所之ZERO ENERGY BUILDING 採用傳統單多晶式之太陽能模組作為立面玻璃,但發現隔熱與視覺效果不佳,後來改採我們之太陽能節能玻璃,已製成3片送往新加坡太陽能研究中心進行安裝前檢 測。另外,美國University of New Mexico之零耗能展示屋的採用,則是該校Prof. Olga在Discovery Channel看到報導,特地搭機來臺參觀並選定,已進入廠商報價與製作階段。(本期專欄策畫/化工系陳文章教授&土木系呂良正主任)
表1:太陽能節能玻璃在臺灣應用案例
表2:太陽能節能玻璃在國外應用案例
楊錦懷小檔案
成功大學土木工程系畢 業(1981),臺灣工業技術學院營建工程技術系碩士(1986),臺灣大學土木工程學博士(1990)。於University of Cambridge的Department of Materials Science & Metallurgy擔任博士後研究,Industrial Research Limited, Crown Research Institute, N.Z的Engineering Dynamics擔任Visiting Research後回臺,獲聘臺灣科技大學營建工程系副教授,現任教授。主持太陽能與節能建築研究,卓有成果。
ONE of the world’s busiest airports, Hartsfield-Jackson in Atlanta, lies a mere 1,026 feet above sea level. Which, it turns out, is perfect for your taste buds.
What are your own experiences — good and bad — with food in flight? Tell what comes to mind in 140 characters or less on Twitter, and include the hash tag #airlinefood.
At low elevations, the 10,000 or so taste buds in the human mouth work pretty much as nature intended. With an assist from the nose — the sense of smell plays a big role in taste — the familiar quartet of sweet, bitter, sour and salty registers as usual. Tomato juice tastes like tomato juice, turkey Florentine like turkey Florentine.
But step aboard a modern airliner, and the sense of taste loses its bearings. This isn’t simply because much airline food is unappetizing, although that doesn’t help. No, the bigger issue is science — science that airlines now want to turn to their advantage as they vie for lucrative business- and first-class travelers.
Even before a plane takes off, the atmosphere inside the cabin dries out the nose. As the plane ascends, the change in air pressure numbs about a third of the taste buds. And as the plane reaches a cruising altitude of 35,000 feet, cabin humidity levels are kept low by design, to reduce the risk of fuselage corrosion. Soon, the nose no longer knows. Taste buds are M.I.A. Cotton mouth sets in.
All of which helps explain why, for instance, a lot of tomato juice is consumed on airliners: it tastes far less acidic up in the air than it does down on the ground. It also helps explain why airlines tend to salt and spice food heavily and serve wines that are full-bodied fruit bombs. Without all that extra kick, the food would taste bland. Above the Atlantic, even a decent light Chablis would taste like lemon juice.
“Subtlety is not well served at altitude,” says Andrea Robinson, a sommelier who has selected wines for Delta Air Lines since 2008.
The science of airline food, which Delta, Lufthansa and other airlines have studied assiduously for years, has opened a new front in the battle for passengers in the upper-class cabins. Until recently, airline food seemed in terminal decline — another victim of widespread cost cuts in this long-troubled industry. Industry experts trace the problem back to 1987, when American Airlines removed a single olive from its salads to save a little money.
Anyone who has flown coach in recent years knows what happened next. Catering budgets were cut drastically. Free meals disappeared from cattle class. It might seem hard to believe, but flight attendants once whisked racks of lamb down the aisles on silver trays. Today, they hawk chips and soda.
But after years of belt-tightening, airline executives are investing again to attract business passengers willing to pay a premium for tickets, and food is a big part of that effort. This includes devising new menus and even hiring celebrity chefs like Gordon Ramsay, of “Hell’s Kitchen” fame, to consult. The motivation is obvious: business and first class account for about a third of all airline seats but generate a majority of the revenue. Keeping high-end customers is crucial to the bottom line.
THE industry can’t afford missteps. Airlines suffered mightily as travelers pulled back after the Sept. 11 terrorists attacks. In the decade that followed, domestic carriers lost a combined $60 billion as competition intensified and fuel prices rose. For many carriers, bankruptcy was the only option. American Airlines was the most recent major airline to do so, last November.
After so much turbulence, airlines are trying to chart a more profitable course through mergers and a renewed focus on business and first class. Many have installed flat-bed seats on some domestic flights, fancier entertainment systems and Wi-Fi.
But in the kitchen, science is still working against airlines. To crack the taste code, Lufthansa, the German airline, went as far as enlisting the Fraunhofer Institute for Building Physics, a research institute near Munich. Among other things, the airline wanted to know why passengers ordered as much tomato juice as beer — about 423,000 gallons of each annually. The answer was that for many passengers, tomato juice apparently has a different taste in different atmospheric conditions.
“We put a lot of effort in designing perfect meals for our clients, but when we tried them ourselves in the air, the meals would taste like airline food,” says Ingo Buelow, who is in charge of food and beverages at Lufthansa. “We were puzzled.”
So are many other people.
“Ice cream is about the only thing I can think of that tastes good on a plane,” says Marion Nestle, a professor of nutrition, food studies and public health at New York University. “Airlines have a problem with food on board. The packaging, freezing, drying and storage are hard on flavor at any altitude, let alone 30,000 feet.”
The journey from recipe book to industrial kitchen to a plane in midflight is fraught with peril. It’s not just a culinary feat — it’s also a logistical nightmare. The $13-billion-a-year airline catering industry serves millions of meals daily worldwide. It must maintain supply chains, standards and quality under a variety of local conditions.
“The cooking is the easy part,” says Corey Roberts, a chef based in New York with LSG Sky Chefs, the biggest catering company. “What we have to worry about is the logistics of getting the correct meal on the correct flight, on the right trays, into the right galley, at the right time. It’s a logistical puzzle of juggling all these meals, every day, for hundreds of flights.”
Catering facilities are part restaurants, part industrial production halls where thousands of workers grill, fry, bake, simmer, boil, poach, beat and braise. Food safety standards require all meals to be cooked first on the ground. After that, they are blast-chilled and refrigerated until they can be stacked on carts and loaded on planes.
In 2010, LSG Sky Chefs produced 460 million meals for 300 airlines in 200 flight kitchens in 50 countries. GateGourmet, the No. 2 caterer, served 9,700 daily flights in 28 countries.
Once all the food is aboard, airlines face another hurdle: planes don’t have full kitchens. For safety, open-flame grills and ovens aren’t allowed on commercial aircraft. Flight attendants can’t touch food the way a restaurant chef might in order to prepare a dish. Galley space is cramped, and there’s little time to get creative with presentation.
So attendants must contend with convection ovens that blow hot, dry air over the food. Newer planes have steam ovens, which are better because they help keep food moist. Either way, meals can only be reheated, not cooked, on board.
“Getting any food to taste good on a plane is an elusive goal,” says Steve Gundrum, who runs a company that develops new products for the food industry.
STILL, there was a time not so long ago when airline food could seem very special. Mr. Gundrum recalls, for example, that he had his best airline meal aboard a British Airways Concorde 25 years ago. It was grouse cooked in a wine reduction, accompanied by little roasted potatoes.
Today, airlines want to recreate some of those glory days in their upper-class cabins, with American carriers — trying to bounce back from years of financial cutbacks — aiming to catch up with foreign rivals’ international service.
And some of those foreign carriers have been raising the stakes. The menu at Air France, for instance, includes Basque shrimp and turmeric-scented pasta with lemon grass. The dishes were created by the chef Joël Robuchon, who has collected a total of 27 Michelin stars in his career. The airline’s roster of chefs also includes Guy Martin, the chef at le Grand Véfour, and Jacques Le Divellec, who runs a restaurant that bears his name in Paris.
Air France isn’t alone in reaching out to celebrity chefs. Lufthansa teams with chefs from the luxury hotel chain Mandarin Oriental to prepare meals for its flights between the United States and Germany. Singapore Airlines, meanwhile, has published a book of in-flight recipes from 10 chefs, including Mr. Ramsay. Its business- and first-class passengers can pick their meals from an online menu 24 hours before takeoff. The airline offers a braised soy-flavored duck with yam rice — a specialty from Singapore — or a seafood thermidor with buttered asparagus, slow-roasted vine-ripened tomatoes and saffron rice.
Korean Air owns a farm where it raises beef and organic grains and vegetables for its in-flight meals, including bibimbap, a Korean classic of rice, sautéed vegetables and chili paste that the airline serves in coach. The farm has more than 1,600 head of cattle and more than 5,000 chickens destined for meals in first class.
And the catering business of Emirates Airlines, in Dubai, handles 90,000 meals a day and bakes its own bread, crumble cake and pecan pie. It also prepares nearly 130 different kinds of menus daily. It offers Japanese and Italian dishes, for instance, and has 12 regional Indian cuisines. Eighteen workers spend their days just making elaborate flower designs out of fruit.
American carriers, while elevating their international food service, have generally shunned such refinements on domestic flights. But Peter Wilander, managing director of onboard services at Delta, wants to bring some glamour back.
Last year, Delta hired Michael Chiarello, a celebrity chef from Napa Valley, to come up with new menus for business-class passengers flying on transcontinental routes — New York to Los Angeles and New York to San Francisco. It was not the first time that Delta had worked with a renowned chef. The airline has served meals created by Michelle Bernstein, a Miami chef, since 2006 in its international business class.
“Our chefs are like portrait painters,” Mr. Wilander says. “They can get pretty creative. But we need to translate that into painting by numbers.” That process began last May, when Mr. Chiarello met with executives and catering chefs from Delta at a boxy industrial kitchen on the edge of the San Francisco airport to demonstrate some of his recipes. Among the dozens of dishes he tried were an artichoke and white-bean spread, short ribs with polenta, and a small lasagna of eggplant and goat cheese.
“I am known for making good food, and airlines generally are not,” says Mr. Chiarello, who is also the author of a half-dozen cookbooks, the host for a show on the Food Network, and a former contestant on “Top Chef Masters” and “The Next Iron Chef.” “I probably have a lot more to lose than to gain doing this.”
Huddled around him, white-toqued chefs from Delta and its catering partners weighed each ingredient on a small electronic scale, took scrupulous notes and pictures and tried to calculate how much it would cost to recreate each dish a thousand times a day.
It took Mr. Chiarello six months to come up with the menu. He tested recipes, picked seasonal ingredients, considered textures and colors and looked at ways to present his meals on a small airline tray. Then Delta’s corporate chefs had to learn his way of cooking and serving. Bean counters — the financial kind — priced each item. Executives and frequent fliers were drafted to taste his creations.
There were a lot of questions. How should cherry tomatoes be sliced? (The answer: Leave them whole.) What side should a chicken fillet be grilled on? (Skin first.) How many slices of prosciutto can be used as appetizers? (Two large ones, rather than three, struck the balance between taste and price.)
FOR airlines like Delta, these are not trivial matters. A decision a few years ago to shave one ounce from its steaks, for example, saved the airline $250,000 a year. And every step of kitchen labor increases costs when so many meals are prepared daily. An entrée accounts for about 60 percent of a meal’s cost, according to Delta, while appetizers account for 17 percent, salads 10 percent and desserts 7 percent.
Delta also calculated that by removing a single strawberry from salads served in first class on domestic routes, it would save $210,000 a year. The company hands out 61 million bags of peanuts every year, and about the same number of pretzels. A one-cent increase in peanut prices increases Delta’s costs by $610,000 a year.
Others are catching on. United Airlines said in February that it would upgrade its service to first- and business-class passengers and would change the way it prepares meals “to improve the quality and taste.” It also said it would start offering a new ice cream sundae option with a choice of six toppings on international flights. On domestic flights, premium passengers will get new snacks, including warm cookies.
At Bottega, his high-end restaurant in Yountville, Calif., Mr. Chiarello specializes in modern Italian flavors, with a focus on fresh ingredients and an obsessive attention to detail in the kitchen and in the dining room. His staff is meticulously trained and has an intimate understanding of the dishes and wines served. And Mr. Chiarello is the undisputed boss of his kitchen.
Translating that in an airline setting is arduous. Delta sent some of its flight attendants based in New York to Mr. Chiarello’s Napa restaurant, and organized Webcasts so others could hear him talk about his food. It also introduced new silverware and trays in time for his new three-course meals.
Delta hopes that passengers will come back if they have a good meal. But for chefs like Mr. Chiarello, airline cooking will always pose challenges.
“If I put a sauce on a plate at my restaurant, I bark at the waiters to hold the plate straight so it doesn’t spill,” he says. “But you can’t bark at the pilot to fly the plane straight, right?”
Just how easy is it to make a deadly virus?
This disturbing question has been on the minds of many scientists recently, thanks to a pair of controversial experiments in which the H5N1 bird flu virus was transformed into mutant forms that spread among mammals.
After months of intense worldwide debate, a panel of scientists brought together by the World Health Organization recommended last week in favor of publishing the results. There is no word on exactly when those papers — withheld since last fall by the journals Nature and Science — will appear. But when they do, will it be possible for others to recreate the mutant virus? And if so, who might they be and how would they do it?
Scientists are sharply divided on those questions, as they are on the whole complex of issues surrounding the mutated virus known as mutH5N1.
On the question of who, while terrorists and cults have long been a concern in biosecurity circles, some scientists also fear that publication may allow curious amateurs to recreate the mutated virus — raising the risk of an accidental release.
Over the past decade, more amateur biologists have started to do genetic experiments of their own. One hub of this so-called D.I.Y. biology movement, the Web site DIYbio.org, now has more than 2,000 members.
“I worry about the garage scientist, about the do-your-own scientist, about the person who just wants to try and see if they can do it,” Michael T. Osterholm of the University of Minnesota said last week at a meeting of biosecurity experts in Washington.
Dr. Arturo Casadevall of the Albert Einstein College of Medicine in New York City, who along with Dr. Osterholm is a member of the scientific advisory board that initially recommended against publishing the papers, agreed. “Mike is right,” he said in a telephone interview. “Humans are very inventive.”
Advocates of D.I.Y. biology say such fears not only are wildly exaggerated, but could interfere with their efforts to educate the public.
“I am really sick and tired of folks waving this particular red flag,” said Ellen D. Jorgensen, a molecular biologist who is president of Genspace, a “community biotechnology lab” in Brooklyn.
There are many ways to make a virus. The simplest and oldest way is to get the viruses do all the work. In the 19th century, doctors produced smallpox vaccines by inoculating cows with cowpox viruses. The viruses replicated in the cows and produced scabs, which were then applied to patients, protecting them from the closely related smallpox virus.
By the turn of the century, scientists had discovered how to isolate a number of other viruses from animals and transfer them to new hosts. And by midcentury scientists were rearing viruses in colonies of cells, which made their study far easier. (Viruses have to infect host cells to reproduce; they cannot replicate on their own.)
More recently, scientists discovered how to make new viruses — or at least new variations on old ones. The biotechnology revolution of the 1970s enabled them to move genes from one virus to another.
Flu vaccines can be made this way. Scientists can move some genes from a dangerous flu strain to a harmless virus that grows quickly in chicken eggs. They inject the engineered viruses into the eggs to let them multiply, then kill the viruses to prepare injectable vaccines.
Scientists have also learned how to tweak individual virus genes. They remove a portion of the gene and then use enzymes to mutate specific sites. Using other enzymes, they paste the altered portion back into the virus’s genes.
Another way to make altered viruses is to harness evolution. In a method called serial passage, scientists infect an animal with viruses. The descendants of those viruses mutate inside the animal, and some mutations allow certain viruses to multiply faster than others. The scientists then take a sample of the viruses and infect another animal.
Viruses can change in important ways during this process. If it is done in the presence of antiviral drugs, scientists can observe how viruses evolve resistance. And viruses can become weak, making them useful as vaccines.
At the biosecurity meeting in Washington last week, Ron Fouchier, who led the Dutch team that created one of the mutant H5N1 viruses, described part of the experiment.
The scientists used well-established methods: First they introduced a few mutations into the H5N1 flu genes that they thought might help the bird flu infect mammals. They administered the viruses to the throats of ferrets, waited for the animals to get sick and then transferred viruses to other ferrets. After several rounds, they ended up with a strain that could spread on its own from one ferret to another in the air.
If trained virologists could see the full details of the paper, there would be several ways they could make mutH5N1 for themselves. The most sophisticated way would be to make the viruses from scratch. They could take the publicly available genome sequence of H5N1 and rewrite it to include the new mutations, then simply copy the new sequence into an e-mail.
“It’s outsourced to companies that do this for a living,” said Steffen Mueller, a virologist at Stony Brook University on Long Island, who regularly synthesizes flu viruses to design new vaccines.
A DNA-synthesis company would then send back harmless segments of the flu’s genes, pasted into the DNA of bacteria. The scientists could cut out the viral segments from the bacteria, paste them together and inject the reconstructed virus genes into cells. If everything went right, the cells would start making mutH5N1 viruses.
The synthesis companies are on the lookout for matches between requested DNA and the genomes of dangerous pathogens. But some experts say such safeguards are hardly airtight. “You could imagine a determined actor could cleverly disguise orders,” Dr. Casadevall said. “I have a lot of respect for human ingenuity.”
Synthesizing viruses has a high-tech glamour about it, but trained virologists could use a simpler method. Knowing the mutations acquired by mutH5N1, they could simply alter ordinary H5N1 viruses at the same sites in its genes to match it.
Virologists might even be able to figure out how to make mutH5N1 from the few details that have already emerged. According to reports, there were only five mutations in the Dutch viruses, and these were most likely at key sites involved in getting viruses into host cells.
Matthew B. Frieman, a virologist at the University of Maryland School of Medicine, said that a review of the scientific literature could point to where the mutations were inserted. “It’s not like nuclear fission,” he said.
Some of the equipment that scientists use to work on viruses has grown so inexpensive that it is no longer limited to university labs. Devices for duplicating pieces of DNA sell for a few hundred dollars on eBay, for example.
Those falling costs have spurred the rise of the D.I.Y. biology movement; they have also generated concerns about what a do-it-yourselfer might be able accomplish.
D.I.Y. biologists sometimes laugh at the sinister powers people think they have. “People overestimate our technological abilities and underestimate our ethics,” said Jason Bobe, a founder of DIYbio.org.
Todd Kuiken, a senior research associate at the Woodrow Wilson Center in Washington who specializes in the movement, points out that typical D.I.Y. projects are relatively simple, like inserting a gene into bacteria to make them glow. Producing viruses involves much more expensive equipment to do things like rearing host cells. “It’s not going to happen in someone’s basement,” he said.
Nor do these amateurs have the years of training it takes to grow viruses successfully. “It’s like I say, ‘I want to be a four-star chef,’ ” said Dr. Jorgensen, the president of Genspace, who worked with viruses for her Ph.D. “You can read about it, but unless someone teaches you side by side, I don’t think you’re going to get far.”
It is hard to predict how the future evolution of biotechnology will affect the risk of homegrown pathogens.
“There ought to be oversight down the road,” Mr. Bobe said. But he and others question whether holding back scientific information can reduce the risk. While it might be challenging to make one particular flu virus, like mutH5N1, it is not hard to try to breed new flu viruses.
“If you are a farmer somewhere in China, you could do it,” said Dr. Mueller, the virologist at Stony Brook. All that would be necessary is to bring some sick chickens in contact with ferrets or other mammals. “Without knowing what you’re doing, you could do it anyway.”
Of course, someone trying to make a new flu this way might well end up its first victim.
And some experts say that regardless of how a lethal virus might arise, the important thing is to be able to defeat it when it appears, so that we can avoid a global catastrophe like the 1918 flu pandemic, which killed 50 million people.
“The only thing that can be done, and to my mind should be done,” said Ron Atlas, a University of Louisville microbiologist and expert on bioterrorism, “is to have a vaccine that protect against this. We need an urgent program for a generalized influenza vaccine. We would take off the table another 1918-type event.”
〔編譯林翠儀/綜合報導〕用蜘蛛絲做成的小提琴琴弦,究竟能拉出什麼音色呢?日本有一名 學者花了2年時間,以上萬根蜘蛛絲做成琴弦,據說拉出來的音色比羊腸弦或金屬弦更厚重、柔和。這項創舉將發表在最新一期的「物理評論快報」 (Physical Review Letters)。
奈良縣立醫科大學的教授大崎茂芳,投入蜘蛛絲研究的歷程可回溯至30多年前。當時,大崎在一家民間企業從事黏著劑的研究工作,發現蜘蛛絲不但有良好的柔軟性和彈性,還具有耐熱性及超強的抗紫外線能力。大崎將蜘蛛絲稱為「夢之纖維」,並探尋其使用方法。
多年前,大崎曾紮出一條直徑約3公分的蜘蛛繩,並成功吊起體重約65公斤的自己。大崎說,文學家芥川龍之介的小說「蜘蛛之絲」描寫佛祖就是吊著蜘蛛絲垂下地獄救人,而他證明了蜘蛛絲果真強韌到足以吊人。
2年前,大崎以一萬根長約一公尺的蜘蛛絲,紮成小提琴的琴弦,這項創舉多次在日本學界和研討會上發表,近期則受到美國權威物理期刊「物理評論快報」注目。大崎希望以蜘蛛絲製成的琴弦未來能普及化,讓樂迷們聽聽這種夢幻音色。
Mar 3rd 2012 | from the print edition
Iran is an earthquake zone, so its engineers have developed some of the toughest building materials in the world. Such materials could also be used to protect hidden nuclear installations from the artificial equivalent of small earthquakes, namely bunker-busting bombs.
To a man with a hammer…
Leon Panetta, America’s defence secretary, seems worried. He recently admitted that his own country’s new bunker-busting bomb, the Massive Ordnance Penetrator (MOP, pictured above being dropped from a B-52), needs an upgrade to take on the deepest Iranian bunkers. But even that may not be enough, thanks to Iran’s mastery of smart concrete.
UHPC is based—like its quotidian cousins—on sand and cement. In addition, though, it is doped with powdered quartz (the pure stuff, rather than the tainted variety that makes up most sand) and various reinforcing metals and fibres.
UHPC can withstand more compression than other forms of concrete. Ductal, a French version of the material which is commercially available, can withstand pressure many times higher than normal concrete can. UHPC is also more flexible and durable than conventional concrete. It can therefore be used to make lighter and more slender structures.
For this reason, Iranian civil engineers are interested in using it in structures as diverse as dams and sewage pipes and are working on improving it. Mahmoud Nili of Bu-Ali Sina University in Hamadan for example, is using polypropylene fibres and quartz flour, known as fume, in his mix. It has the flexibility to absorb far heavier blows than regular concrete. Rouhollah Alizadeh of the University of Tehran may do better still. Dr Alizadeh, a graduate of the University of Tehran, is currently working at Ottawa University in Canada on the molecular structure of cement. That could pave the way for a new generation of UHPC with precisely engineered properties and outstanding performance.
One way to tamper with the internal structure of concrete is to use nanoparticles. Ali Nazari and his colleagues at Islamic Azad University in Saveh have published several papers on how to do that with different types of metal-oxide nanoparticles. They have worked with oxides of iron, aluminium, zirconium, titanium and copper. At the nanoscale materials can take on extraordinary properties. Although it has been demonstrated only in small samples, it might be possible, using such nanoparticles, to produce concrete that is four times stronger than Ductal.
All of which is fine and dandy for safer dams and better sewers, which threaten no one. But UHPC’s potential military applications are more intriguing—and for many, more worrying. A study published by the University of Tehran in 2008 looked at the ability of UHPC to withstand the impact of steel projectiles. These are not normally a problem during earthquakes. This study found that concrete which contained a high proportion of long steel fibres in its structure worked best. Another study, published back in 1995, showed that although the compressive strength of concrete was enhanced only slightly by the addition of polymer fibres, its impact resistance improved sevenfold.
Western countries, too, have been looking at the military uses of UHPC. An Australian study carried out between 2004 and 2006 confirmed that UHPC resists blasts as well as direct hits. The tests, carried out at Woomera (once the British empire’s equivalent of Cape Canaveral), involved a charge equivalent to six tonnes of TNT. This fractured panels made of UHPC, but did not shatter them. Nor did it shake free and throw out fragments, as would have happened had the test been carried out on normal concrete. In a military context, such shards flying around inside a bunker are a definite plus from the attackers’ point of view, but obviously not from the defenders’.
Those people who design bunker-busters no doubt understand these points and have their own secret data to work with. Nevertheless, during the Gulf war in 1991 the American air force found that its 2,000lb (about a tonne) bunker-busters were incapable of piercing some Iraqi bunkers. The bomb designers went back to the drawing board and after two generations of development the result, all 13 tonnes of it, is the MOP. So heavy is it that the weapon bays of B-2 stealth bombers have had to be strengthened to carry it. It can, reportedly, break through over 60 metres of ordinary concrete. However, the bomb it is less effective against harder stuff, penetrating only eight metres into concrete that is just twice as strong. It is therefore anyone’s guess (at least, anyone without access to classified information) how the MOP might perform against one of Iran’s ultra-strong concretes.
America’s Defence Threat Reduction Agency (DTRA), the organisation that developed the MOP, has been investigating UHPC since 2008. This investigation has involved computer modelling and penetration testing. The agency’s focus appears to be on the idea of chipping away at a target with multiple hits. However, this approach requires great precision; and the air force is ordering only 20 MOPs, so there is little room for error.
Deep bunkers can be tackled in other ways. The DTRA has looked at what is known in the jargon as functional defeat, in other words bombing their entrances shut or destroying their electrical systems with electromagnetic pulses. They are also working on active penetrators—bombs which can tunnel through hundreds of metres of earth, rock and concrete. Development work is also under way on esoteric devices such as robot snakes, carrying warheads, which can infiltrate via air ducts and cable runs.
In the meantime, though, the Pentagon is stuck with the “big hammer” approach. The question is how reliably that hammer would work if the order were given to attack Iran’s underground nuclear facilities. It would be embarrassing if the bunkers were still intact when the smoke cleared.