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Concrete is probably used more widely than any other substance except water, yet it remains largely unappreciated. "Some people view the 20th century as the atomic age, the space age, the computer age — but an argument can be made that it was the concrete age, " says cement specialist Hendrik Van Oss. "It"s a miracle material." Indeed, more than a ton of concrete is produced each year for every man, woman and child on Earth. Yet concrete is generally ignored outside the engineering world, a victim of its own ubiquity and the industry"s conservative pace of development. Now, thanks to environmental pressures and entrepreneurial innovation, a new generation of concretes is emerging. This high-tech assortment of concrete confections promises to be stronger, lighter, and more environmentally friendly than ever before. Concrete is also a climate-change villain. It is made by mixing water with an aggregate, such as sand or gravel, and cement. Cement is usually made by heating limestone and clay to over 2, 500 degrees F. The resulting chemical reaction, along with fuel burned to heat the kiln, produces between 7% and 10% of global carbon-dioxide emissions. "When we have to repeatedly regenerate these materials because they"re not durable, we release more emissions, " says Victor Li who has created a kind of concrete suffused by synthetic fibers that make it stronger, more durable, and able to bend like a metal. Li"s creation does not require reinforcement, a property shared by other concretes that use chemical additives. Using less water makes concrete stronger, but until the development of plasticizers, it also made concrete sticky, dry, and hard to handle, says Christian Meyer, a civil engineering professor at Columbia University. Making stronger concretes, says Li, allows less to be used, reducing waste and giving architects more freedom. "You can have such futuristic designs if you don"t have to put rebar in there, or structural beams, " says Van Oss. A more directly "green" concrete has been developed by the Australian company TecEco. They add magnesium to their cement, forming a porous concrete that actually scrubs carbon dioxide from the air. While experts agree that these new concretes will someday be widely used, the timetable is uncertain. Concrete companies are responsive to environmental concerns and are always looking to stretch the utility of their product, but the construction industry is slow to change. "When you start monkeying around with materials, the governing bodies, the building departments, are very cautious before they let you use an unproven material," Meyer says. In the next few decades, says Van Oss, building codes will change, opening the way for innovative materials. But while new concretes may be stronger and more durable, they are also more expensive — and whether the tendency of developers and the public to focus on short-term rather than long-term costs will also change is another matter. Which of the following is true about Li"s new "green" concrete
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In 1999, the price of oil hovered around $ 16 a barrel. By 2008, it had【C1】______the $ 100 a barrel mark. The reasons for the surge【C2】______from the dramatic growth of the economies of China and India to widespread【C3】______in oil-producing regions, including Iraq and Nigeria"s delta region. Triple-digit oil prices have【C4】______the economic and political map of the world, 【C5】______some old notions of power. Oil-rich nations are enjoying historic gains and opportunities, 【C6】______major importers — including China and India, home to a third of the world"s population —【C7】______rising economic and social costs. Managing this new order is fast becoming a central【C8】______of global politics. Countries that need oil are clawing at each other to【C9】______scarce supplies, and are willing to deal with any government, 【C10】______how unpleasant, to do it. In many poor nations with oil, the profits are being, lost to corruption, 【C11】______these countries of their best hope for development. And oil is fueling enormous investment funds run by foreign governments, 【C12】______some in the west see as a new threat. Countries like Russia, Venezuela and Iran are well supplied with rising oil【C13】______a change reflected in newly aggressive foreign policies. But some unexpected countries are reaping benefits, 【C14】______costs, from higher prices. Consider Germany. 【C15】______it imports virtually all its oil, it has prospered from extensive trade with a booming Russia and the Middle East. German exports to Russia【C16】______128 percent from 2001 to 2006. In the United States, as already high gas prices rose【C17】______higher in the spring of 2008, the issue cropped up in the presidential campaign, with Senators McCain and Obama【C18】______for a federal gas tax holiday during the peak summer driving months. And driving habits began to【C19】______as sales of small cars jumped and mass transport systems【C20】______the country reported a sharp increase in riders. 【C10】
In 1999, the price of oil hovered around $ 16 a barrel. By 2008, it had【C1】______the $ 100 a barrel mark. The reasons for the surge【C2】______from the dramatic growth of the economies of China and India to widespread【C3】______in oil-producing regions, including Iraq and Nigeria"s delta region. Triple-digit oil prices have【C4】______the economic and political map of the world, 【C5】______some old notions of power. Oil-rich nations are enjoying historic gains and opportunities, 【C6】______major importers — including China and India, home to a third of the world"s population —【C7】______rising economic and social costs. Managing this new order is fast becoming a central【C8】______of global politics. Countries that need oil are clawing at each other to【C9】______scarce supplies, and are willing to deal with any government, 【C10】______how unpleasant, to do it. In many poor nations with oil, the profits are being, lost to corruption, 【C11】______these countries of their best hope for development. And oil is fueling enormous investment funds run by foreign governments, 【C12】______some in the west see as a new threat. Countries like Russia, Venezuela and Iran are well supplied with rising oil【C13】______a change reflected in newly aggressive foreign policies. But some unexpected countries are reaping benefits, 【C14】______costs, from higher prices. Consider Germany. 【C15】______it imports virtually all its oil, it has prospered from extensive trade with a booming Russia and the Middle East. German exports to Russia【C16】______128 percent from 2001 to 2006. In the United States, as already high gas prices rose【C17】______higher in the spring of 2008, the issue cropped up in the presidential campaign, with Senators McCain and Obama【C18】______for a federal gas tax holiday during the peak summer driving months. And driving habits began to【C19】______as sales of small cars jumped and mass transport systems【C20】______the country reported a sharp increase in riders. 【C9】
Concrete is probably used more widely than any other substance except water, yet it remains largely unappreciated. "Some people view the 20th century as the atomic age, the space age, the computer age — but an argument can be made that it was the concrete age, " says cement specialist Hendrik Van Oss. "It"s a miracle material." Indeed, more than a ton of concrete is produced each year for every man, woman and child on Earth. Yet concrete is generally ignored outside the engineering world, a victim of its own ubiquity and the industry"s conservative pace of development. Now, thanks to environmental pressures and entrepreneurial innovation, a new generation of concretes is emerging. This high-tech assortment of concrete confections promises to be stronger, lighter, and more environmentally friendly than ever before. Concrete is also a climate-change villain. It is made by mixing water with an aggregate, such as sand or gravel, and cement. Cement is usually made by heating limestone and clay to over 2, 500 degrees F. The resulting chemical reaction, along with fuel burned to heat the kiln, produces between 7% and 10% of global carbon-dioxide emissions. "When we have to repeatedly regenerate these materials because they"re not durable, we release more emissions, " says Victor Li who has created a kind of concrete suffused by synthetic fibers that make it stronger, more durable, and able to bend like a metal. Li"s creation does not require reinforcement, a property shared by other concretes that use chemical additives. Using less water makes concrete stronger, but until the development of plasticizers, it also made concrete sticky, dry, and hard to handle, says Christian Meyer, a civil engineering professor at Columbia University. Making stronger concretes, says Li, allows less to be used, reducing waste and giving architects more freedom. "You can have such futuristic designs if you don"t have to put rebar in there, or structural beams, " says Van Oss. A more directly "green" concrete has been developed by the Australian company TecEco. They add magnesium to their cement, forming a porous concrete that actually scrubs carbon dioxide from the air. While experts agree that these new concretes will someday be widely used, the timetable is uncertain. Concrete companies are responsive to environmental concerns and are always looking to stretch the utility of their product, but the construction industry is slow to change. "When you start monkeying around with materials, the governing bodies, the building departments, are very cautious before they let you use an unproven material," Meyer says. In the next few decades, says Van Oss, building codes will change, opening the way for innovative materials. But while new concretes may be stronger and more durable, they are also more expensive — and whether the tendency of developers and the public to focus on short-term rather than long-term costs will also change is another matter. The last sentence of the text shows that
The question of where insights come from has become a hot topic in neuroscience, despite the fact that they are not easy to induce experimentally in a laboratory. Dr. Bhattacharya and Dr. Sheth have taken a creative approach. They have selected some brain-teasing but practical problems in the hope that these would get closer to mimicking real insight. To qualify, a puzzle had to be simple, not too widely known and without a methodical solution. The researchers then asked 18 young adults to try to solve these problems while their brainwaves were monitored using an electroencephalograph (EEG). A typical brain-teaser went like this. There are three light switches on the ground-floor wall of a three-storey house. Two of the switches do nothing, but one of them controls a bulb on the second floor. When you begin, the bulb is off. You can only make one visit to the second floor. How do you work out which switch is the one that controls the light This problem, or one equivalent to it, was presented on a computer screen to a volunteer when that volunteer pressed a button. The electrical activity of the volunteer"s brain (his brainwave pattern) was recorded by the EEG from the button"s press. Each volunteer was given 30 seconds to read the puzzle and another 60 to 90 seconds to solve it. Some people worked it out; others did not. The significant point, though, was that the EEG predicted who would fall where. Those volunteers who went on to have an insight (in this case that on their one and only visit to the second floor they could use not just the light but the heat produced by a bulb as evidence of an active switch) had had different brainwave activity from those who never got it. In the right frontal cortex, a part of the brain associated with shifting mental states, there was an increase in high-frequency gamma waves (those with 47~48 cycles a second). Moreover, the difference was noticeable up to eight seconds before the volunteer realised he had found the solution. Dr. Sheth thinks this may be capturing the "transformational thought" in action, before the brain"s "owner" is consciously aware of it. This finding poses fascinating questions about how the brain really works. Conscious thought, it seems, does not solve problems. Instead, unconscious processing happens in the background and only delivers the answer to consciousness once it has been arrived at. Food for further thought, indeed. The EEG would predict the success of a volunteer
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