VOA标准英语2010年-Our World – 2 January 2010（在线收听）

VOA's Weekly Science and Technology Magazine

Art Chimes 05 January 2010

MUSIC: "Our World" theme

This week on a special edition of "Our World," some of our favorite stories of the past year ... including a high-tech wrinkle to that humblest of building materials, concrete ...  a robotic approach to harvesting hard-to-harvest crops  ... and – during efforts to restore oyster populations in the Chesapeake Bay – some surprising facts about the bi-valves:

MERITT:  "Once they find that, they actually cement themselves to that substrate. They then have lost the ability to move themselves around. So if you're an oyster you get one shot to pick the place you're going to live the rest of your life, and you better be smart at it."

Those stories, highlights from our Websites of the Week, and bringing a 19th century home entertainment technology into the digital age

I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Robots Spread Seeds of Change in Fruit Orchards

Let's start on the farm, where mechanization has made the modern farmer's life a lot easier. That's especially true for those who grow crops like wheat, soy, or corn on big, broad fields.  But the story is quite different for growers who raise crops that require intensive hand labor to plant and harvest. Growers of these so-called specialty crops have long hoped for more mechanization to come to their farms. As VOA's Rosanne Skirble reports, they might soon find an answer in a new robotic technology.

SKIRBLE:  Craig Senovich grew up in the rolling hills of western Pennsylvania.  His great grandfather owned the land and planted vegetables, but Senovich, an engineer by day, just opened Half Crown Hill Orchard four years ago.

SENOVICH:  "There was really just a lot of crab apple trees and brush, and it took us several months just of digging out trees and clearing the land and preparing the soil."

SKIRBLE:  Senovich fenced in a 1.2 hectare plot, planted 1,300 trees, and installed a drip irrigation system. Field sensors and a weather station are linked to his personal computer and track important data related to the crop's well-being.

SENOVICH:  "And I also have a leaf wetness monitor that depending on how wet, and how long and what temperatures different funguses will grow and then [I] determine when and what to spray, rather than just spraying all the time."

SKIRBLE:  Half Crown Hill Orchard is also a robotic technology test site for a United States Department of Agriculture project looking at ways of mechanizing the production of specialty crops like apples. 

SENOVICH:  "It would be nice to be able to have some automated stuff even just to mow the lawn.  It takes me many hours just to come down here and mow."

SINGH:  "Mowing is easy. We could attach a mowing attachment to the back of this vehicle and as it goes along, it could make sure that the vegetation doesn't grow too high here in the middle of the rows."

SKIRBLE:  That's Sanjiv Singh, a Carnegie Mellon University robotics professor, who is charged with developing systems for the apple industry. Today he's working with a battery powered electric utility vehicle that drives itself. Two laser scanners mounted on the front bumper, each taking 13,000 measurements per second, help plot its course.  

Singh says added sensors and cameras could eventually give growers continuous updates on crop status and early warning of disease and insect infestation. 

SINGH:  "This is simple technology coupled with sensors that are available today that might be able to give a farmer a lot more information that they are able to [use]. This is a small orchard, but you can imagine orchards that are hundreds of acres where it is impossible to go up and down the rows very frequently."

SKIRBLE:  Another USDA applied robotics project takes Cris Dima to Florida. The southeastern U.S. state is second only to Brazil in citrus production worldwide. Dima is a scientist at the National Robotics Engineering Center at Carnegie Mellon, and he has just spent several weeks in one of the state's largest orange groves testing a network of autonomous, or driverless, tractors. 

DIMA:  "So imagine for example, that the grower or somebody hired to monitor the tractors sits in an office somewhere or in a pickup truck somewhere in the grove and monitors the activities of four autonomous tractors, or more,  performing operations such as spraying or mowing or things like that."

SKIRBLE:  Robots could also be engineered to administer precise amounts of water or chemicals to specific trees. Dima says the goal is not to develop an entirely autonomous operation, but rather to integrate technology the farmer needs at an affordable price.

DIMA:  "Beyond proving that this is possible, there is work to be done in reducing the cost of the technology, making it robust and transferring it to somebody who can commercialize it."

SKIRBLE:  Back at Half Crown Hill Orchard, Sanjiv Singh says it's going to take growers like Craig Senovich, engaged in the process, to move this technology into the marketplace.  

SINGH:  "We've been working on this robotics technology, automation technology, for like 25 years and from a technology perspective, some of the things, are fairly well in hand.  It is going to be, how do we create the value? The things that are well in hand, do they generate enough dollars for people."

SKIRBLE:  Farmer Craig Senovich nods in agreement as he watches the electric vehicle drive itself safely down rows of budding trees in his orchard. He's hoping these test runs will soon advance to the next step, and start providing fruit and vegetable growers with some automated and money-saving solutions. I'm Rosanne Skirble, VOA News, in Western Pennsylvania.

In Search of Green(er) Concrete

On the farm or in the city, builders often turn to concrete, as they have for more than 2,000 years. It's strong, flexible, and easily adapted for a wide variety of construction uses. So it's no wonder concrete is the most widely used man-made building material. Unfortunately, making concrete is not an environmentally friendly process. So back around Earth Day, VOA's Adam Phillips reported on what's being done to make concrete "greener," without sacrificing low cost and legendary durability.

MEYER:  "It's very strong and, if it's done correctly, it can be very durable. The Romans built structures 2000 years ago like the Pantheon. It's still doing very well 2,000 years later."

PHILLIPS:  That's Christian Meyer head of Columbia University's Department of Civil Engineering. He says concrete's so-called "mechanical properties" explain its universal popularity as a building material.   

MEYER:  "Also, it is very affordable, very cheap, compared to with other building materials. And you can get it everywhere. You make concrete in almost every country in the world because the ingredients that you need you find everywhere."

PHILLIPS:  Every year, nearly a cubic meter of concrete is produced for every man, woman, and child on the planet. Meyer says satisfying that demand requires a lot of land.     

MEYER:  "If you want to produce ten billion cubic meters of concrete, you need ten billion meters of material, okay?  That's the conservation of mass. And where do you get that? You have to quarry the stone, you have to quarry the aggregate and get the sand from sand pits. That's a huge amount of materials ." 

PHILLIPS:  But concrete's very durability is also one of its biggest drawbacks, according to architect and Columbia University professor Michael Bell.

BELL:  "It's not a material that comes down easily when it's put up. So whatever we are building in Beijing, Shanghai, in India right now, those buildings are going to stay. Or if they aren't going to stay, getting them down is going to produce a massive amount of waste."

PHILLIPS:     Until recently, most of the world's used concrete went into landfills, at enormous environmental cost. But today, some manufacturers, especially in Europe, are crushing used concrete and recycling it for use as an ingredient in new concrete. The United States lags behind in these efforts, but many American state highway departments are interested in the process.
 
The greatest environmental threat associated with concrete is that the processing of one of its key ingredients, cement, releases large amounts of carbon dioxide, or CO2, a greenhouse gas associated with global warming. About a metric ton of CO2 is created for each metric ton of cement produced, and the process now accounts for as much as seven percent of the world's industrial CO2 emissions.

Why so much CO2?

First, CO2 is created as a natural chemical byproduct when the ingredients in traditional cement – called Portland cement – are combined. Second, cement is made by heating a chemical mixture – mostly limestone, clay, iron ore and other minerals – in a kiln to high temperatures usually exceeding 1500 degrees celsius. The energy for that heat usually comes from burning oil or coal, both of which release CO2 during combustion. Fortunately, says Christian Meyer, there are ways to reduce the carbon footprint of the cement we make and use. 

MEYER:  "The most common one is that we simply use less cement and replace it with some other material that has cementicious [cement-like] properties and happen to be byproducts of other industrial processes. The most common example that is well known is fly ash. Fly ash is a byproduct of coal combustion." 

PHILLIPS:  U.S. federal law now requires that power plants either capture this fly ash so it doesn't pollute the atmosphere, or pay a hefty fine for the fly ash that is released.

MEYER:  "But it was found that this fly ash is an excellent cementitious material. Because it can react together with the cement and the water and produce better concrete if you use fly ash than if you don't use fly ash. Not only that, it's also cheaper than cement. So it's a win-win situation here."

PHILLIPS:  It is projected that power plants in the future may be built alongside cement factories, so that the waste from one industry may be easily used as the raw material for another.

PHILLIPS:  Also, new types of cement are being developed or are already in use. One  uses titanium oxide particles that break down many of the organic pollutants already in the air, and help clean the atmosphere. In an era when nations around the world are industrializing, and cities are growing at an unprecedented pace, making the world's favorite building material a little greener is an achievement as solid as…concrete.

I'm Adam Phillips reporting from New York.
 

Websites of the Week Recreate Moon Landing, Bring University Courses to Your Computer

A regular feature here on Our World is the Website of the Week, in which we showcase interesting and innovative online destinations.

We don't have time to review all the ones we featured in 2009, but I did want to highlight a few of them.

This past year we celebrated the 40th anniversary of Apollo 11 and the first landing of humans on the moon.

The historic flight was recreated on WeChooseTheMoon.org, combining animation with a vast library of archival audio, video, and photography.

LEWIS:  "Over 100 hours of audio transmissions, news photos, and video, and speeches from [President] John F. Kennedy. And it may be the new way that we aggregate, in this digital world, history."

Regina Lewis is consumer advisor at AOL, the Internet company that is hosting We Choose The Moon, which is a project of the John F. Kennedy Presidential Library. She says they've tried to recreate the historic feel of the 1960s along with some contemporary updates, like a Twitter feed.

There were some interesting developments in Internet search this year. Microsoft launched its challenge to Google's dominance with the well-received Bing search site. At Wolfram Research, the company that publishes the powerful Mathematica software, they have a different approach to finding answers on a new website they introduced in May.

WEISSTEIN:  "Wolfram Alpha is a computational knowledge engine. It's not a search engine, but rather a way to search kind of the computational universe. So it knows all about facts, figures, and it can do sorts of queries that traditional search engines have difficulty with."

Eric Weisstein is a senior researcher at Wolfram. Unlike conventional search engines, Wolfram Alpha returns answers from its own database, which has been reviewed for accuracy. It's meant to be more focused and analytical than a general-purpose search product.

And one more we featured in 2009: a website for learning without leaving the comfort of your own computer.

LUDLOW:  "AcademicEarth is a free website that gives people around the world access to full courses and video lectures from some of the world's top universities."

Richard Ludlow is the founder of AcademicEarth.org, a website that collects video courses and lectures from leading teachers at seven of America's top universities.

Those are just a few examples to highlight the diversity of the web. We have links to these and more than 250 other Websites of the Week on our website, which is voanews.com/ourworld.

MUSIC: Don Harriss – "Inventions"

And you're listening to VOA's science and technology magazine, Our World.  I'm Art Chimes in Washington.

Volunteers Help Restore Chesapeake Bay Oysters

The Chesapeake Bay, about an hour's drive east of Washington, is America's largest estuary – where fresh river water meets and mixes with the ocean's salt water. Oysters once flourished in the Chesapeake, which provided a habitat for many forms of aquatic life and supported a thriving oyster industry. But pollution and decades of overharvesting have drastically reduced the oyster population. Efforts to restore their numbers are underway in many parts of the Bay. One oyster recovery project is getting Chesapeake Bay-area residents involved, as Veronique LaCapra reports.

LaCAPRA:  On a warm, sunny morning in late August, volunteers gather at a marina on Maryland's Severn River, one of the tributaries of the Chesapeake Bay on the U.S. mid-Atlantic coast.

JUDY:  "Today is the kick-off of our Marylanders Grow Oysters program."

LaCAPRA:  Chris Judy directs the program for the Maryland Department of Natural Resources.

JUDY:  "What's going to happen is, a truck will arrive with cages loaded with oyster spat – young oysters – the cages will be loaded on boats and trucks and distributed to the volunteer oyster growers we have."

LaCAPRA:  These volunteer oyster growers are local residents who live along the rivers that flow into the Chesapeake Bay. Each volunteer will take care of several cages filled with about 80 oyster shells. Attached to each shell are about ten baby oysters – called spat – each less than a millimeter in diameter.

LaCAPRA:  The spat come from the University of Maryland's Horn Point Laboratory. Don Merritt runs the lab's oyster hatchery restoration program.

MERITT:  "The oyster life cycle is fairly complex. Oysters in the winter have no developed gonad at all, in fact you can't even tell a male from a female."

LaCAPRA:  As the water temperature warms up in the spring, the oysters start to produce eggs and sperm. In the summer, once the water gets warm enough…

MERITT:  "…they release those eggs and sperm out into the water column where fertilization occurs."

LaCAPRA:  At the hatchery, Meritt and his staff can manipulate water temperature to control the oysters' reproductive cycle.

MERITT:  "The hissing noise that you hear is pneumatic valves that are opening and closing, which is pulsing chilled river water in with the warm ambient river water right now, to maintain their proper conditioning temperature."

LaCAPRA:  A single female will typically release ten to thirty million eggs, during a half hour spawning event. The fertilized eggs hatch into oyster larvae, each smaller than a grain of sand.

MERITT:  "In nature, almost none of those survive."

LaCAPRA:  At the hatchery, a sophisticated computerized system delivers four species of algae to hungry oyster larvae in eight tanks of water, each holding close to 38,000 liters. In a lab near the larval tanks, Don Meritt takes a small plastic container out of a refrigerator and unwraps what looks like a blob of brown muck.

MERITT:  "5.4 million oyster larvae."

LaCAPRA:  Meritt smears a bit of the muck on a slide and puts it under a microscope. Magnified through the lens, the muck transforms into dozens of tiny, translucent pairs of shells.

LaCAPRA:  In the water, the oyster larvae propel themselves around with tiny hair-like structures called cilia. After a few weeks, the ones that have survived start to settle to the bottom.

MERITT:   "At that point they look like a little snail. And they crawl around looking for a piece of hard, clean substrate that suits them. Once they find that, they actually cement themselves to that substrate. They then have lost the ability  to move themselves around. So if you're an oyster you get one shot to pick the place you're going to live the rest of your life, and you better be smart at it."

LaCAPRA:  In the Chesapeake Bay, oyster larvae try to improve their chance of survival by attaching themselves to other oysters.

At the hatchery, the larvae settle down as spat in large outdoor tanks, each holding eight stainless steel mesh cages filled with 96,000 oyster shells. Last year, the hatchery produced over 550 million spat, for a wide range of oyster restoration sites: some for harvest, and some for protected sanctuaries – like those supported by the Marylanders Grow Oysters program.
   
McCOLLUM:  "Alright, so I'll start handing them down to you."

LaCAPRA:  This is Tom McCollum's first year as a volunteer.

McCOLLUM:  "We've been pretty excited about this program for a number of years, and we're just happy they're bringing it to our neighborhood. And it's just a great way to teach my kids as well as make a difference."

LaCAPRA:  The McCollum family will be caring for three oyster cages in the water off their pier – the program plans to distribute a total of five thousand to area residents.

After about nine months, the Maryland Department of Natural Resources will collect the oysters and transfer them to a sanctuary in the Severn River. As adults, they will provide many environmental benefits, filtering algae and sediment out of the water, and creating habitat for crabs, fish, and other aquatic life.

Although Horn Point Lab's Don Meritt says the number of oysters these volunteers raise will be relatively small compared to overall Chesapeake Bay restoration efforts, he stresses that the real benefits of the program are educational:

MERITT:  "It demonstrates to the property owners and their kids and their grandkids and their neighbors, everybody around, just how unique oysters are and how the Chesapeake Bay is going to be so much better off for everybody if we can get enough oysters back out there to start doing the job that they used to do."

Véronique LaCapra, for VOA News.

Century-old Music Reproduction Technology Endures

Finally today, digital music meets one of the first mass market home entertainment technologies

Listen for a moment to this top-10 hit that blends some of the newest and some of the oldest recording technology.

MUSIC: "Home Again Blues"

That sparkling digital recording was actually made almost 90 years ago.  Well, sort of.

What sounds like a piano is actually a computerized rendition of a 1920 piano roll, a 29 centimeter-wide continuous sheet of paper perforated to correspond to the notes played, and which replays those notes on a specially-equipped piano. The "player piano" was the home entertainment center for many middle class families around the world in the late 19th and early 20th century – the big screen TV of its day.

The song, incidentally, was "Home Again Blues," a big hit for Irving Berlin and Harry Akst.

In January we reported that the last maker of piano rolls, a company called QRS in Buffalo, New York, had finally stopped production.

Hobbyists are keeping the old technology alive, however, restoring and maintaining the old pianos and, in the latest wrinkle, scanning the rolls and converting them into computer files, so you can put them on your portable player and enjoy them wherever you go. Which is definitely easier than taking your player piano to the beach.

MUSIC: "By The Beautiful Sea"

MUSIC: "Our World" theme

That's our wrap-up of some of our favorite stories from 2009.

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