Researchers around the world have been trying their hand at making better use of the huge amount of wind energy available in nature to produce clean energy. Apart from this, studies are being carried out to harness(利用) usable windenergy produced by man-made technologies.

    One useful source identified by Indian inventor Santosh Pradhan about two years ago is a speeding train, which produces fierce wind that can betrans formed into electricity.

    According to Pradhan's proposal, with a few small improvements in existing trains running in Mumbai, the largest city in India, at least 10,000 megawatts(兆瓦) of electricity could be harvested each day.

    Building on this principle, designers Ale Leonetti Luparinia and Qian Jiang from Yanko Design have created a device(装置) called T-Box that harnesses wind energy from speeding trains.

    T-Box can be placed within the railway tracks. It is half-buried underground between the concrete sleepers(水泥枕木), which does not disturb the normal train operating at all. According to Yanko, around 150T-Boxes can be fitted along a 1,000-meter railway track.

    A train running at a speed of 200 kph can produce winds blowing at 15 miles a second. Based on this calculation, 150 T-Boxes can produce 2.6 KWH of electricity per day. The T-Box's design won a silver medal in last year's Lite-On Awards and was exhibited last summer at the Xue Xue Institute inTaipei, Taiwan Province.

    Though the figures look impressive, it is important to remember that the design is still at a conceptual stage and hasn't taken into account issues such as pieces of waste material produced by the device and the efforts and costs involved in the maintenance(维护) of the device.

    We can expect the technology to see the light of the day only after it clears these issues. If so, rail travel, one of the greenest forms of travel, will become greener and more energy-efficient.

    On a Saturday morning earlier this September, the world got its first look at the Strati. This electric vehicle is unlike any other currently on the road. It rolls on four wheels, but its body and chassis(底盘) weren't built in a factory. Instead, Strati's designers used a technology called 3-D printing. It created those parts of the car in one piece, from the ground up.

    “Compared to a typical vehicle on the road, the Strati definitely looks different,” says Greg Schroeder, a senior research engineer at the Center for Automotive Research in Ann Arbor, Mich. He did not work on the new car. His organization studies trends and changes in th e auto industry.

    It took 44 hours to print the new car at the International Manufacturing Technology Show in Chicago. Over the next few days, the car's designers installed additional parts. These included the car's engine, brakes and tires. Then, early on September 13, Jay Rogers climbed into the car, started its engine and drove the vehicle onto the street. Rogers helped found Local Motors. It's the Arizona-based company behind the Strati. Two weeks later, his team printed a second Strati, and just as fast, at a fair in New York City.

    Justin Fishkin, a local Motors official, sees the Strati as a window into the future. Today, car buyers are limited in their choice of a vehicle. They can order only what car companies have already designed. But in the future, he says, you may be able to design your own car online and then get it printed to order.

    Manufacturing experts say 3-D printing has begun to revolutionize how they make things. The technology has been around for decades. But these machines used to be so expensive that only large companies could afford them. In the last few years, though, that has changed. Many of the machines are now inexpensive enough for small companies—or even individuals —to own. Some local libraries make them available to the public. High Schools are beginning to use them in classrooms. Wide access to these printers means people can now design and print a wide variety of new things.

    The car's printer is a one-of-a-kind device.

    The technology behind the 3-D printer used in Chicago is an example of additive manufacturing. This proce ss builds solid objects, slice by slice, from the bottom up. (“Strati” means layers, in Italian.) A mechanical arm moves a nozzle from one side to another, back and forth. As it moves, the nozzle deposits a liquid—often melted plastic or metal (but it could be food, concrete or even cells) —that quickly hardens or bonds to become solid or semi-solid. This creates a single, thin layer. Once a layer is complete, the printer starts depositing the next one.

    “There's a lot of interest in 3-D printing in the auto industry,” says Schroeder. Right now, the technology is particularly useful for building models of cars or car parts.

    To compete with current auto manufacturers, the 3-D printer would have to increase in a hurry, Schroeder says. By contrast, he notes, a Ford F-150 pickup truck rolls off an assembly line at a rate of roughly one per minute. To print as many Stratis would require many more printers. Schroeder says he doesn't see 3-D printing soon taking over for such high-volume manufacturing. But, he adds, “Who knows what will h appen in the long term?”

    Scientists at Oak Ridge National Laboratory in Tennessee designed the 3-D printer used in Chicago. Lonnie Love, a research scientist at the lab, led the effort.

    Additive manufacturing often is slow and expensive. It also may produce materials that are unreliable, Love says. So for two years, his team searched for ways to make 3-D printing better. They built new machines and tested them over and over.

    All of that work paid off: their new machine is fast and uses less expensive material than earlier printers. In addition, it prints a plastic embedded with fibers of carbon to produce a stronger material. This helps ensure the material won't crack or break under pressure.

    Everyone wants to win, and everybody knows it. Take the case of Olympic athletes, who train hard each day for years to reach the top of their sport and hopefully win a gold medal. Since every competitor's goal is to win, we assume that the silver medalists would be less happy than gold-medal winners, but still happier than those in third place. Common sense says that our levels of happiness should have something to do with our levels of achievement – except that often this isn't the case.

    Researchers found that bronze medalists actually appeared on the whole to be happier than silver medalists. How could that be? The answer, in a word, is gratitude. Silver medallists, who compared themselves to the gold medalists, experienced disappointment at having been close to winning the gold, but falling short. The bronze medalists, on the other hand, were thankful to have won a medal at all, comparing themselves to all those who didn't even reach the Olympic platform.

    If happiness, then, is the aim of life, perhaps our achievement-centered culture is getting it all backwards. We focus on what we want rather than on what we have. We forget to be grateful, and as a result we forget to be happy.

    We're from a culture that teaches us to envy others – another person achievements – and that is always looking forward to what comes next. Yet in a better society, might we not look at what all of our earlier nexts have already earned us?

    I encourage any person who struggles with frustration （挫折）in their life to take out a notebook and a pen each evening before bed, and to write down all the things that they have gratitude for. It's not a cure for dissatisfaction, to be sure, but many people quickly discover that, when they actually stop to think about it, they have things pretty good and happiness comes.

    Those bronze medalists, after all, can't be wrong.

    I was so fortunate today to be able to offer my love and help to an older lady at my local supermarket. I saw her standing there. I felt quite strange about such a situation.

    What was she looking at? As I looked, I found it was a "Shredded Pork Bun Meal Kit", which is a service that sends customers food ingredients and recipes for them to prepare their own fresh meals. "That's new," I thought. Then I watched as the lady began to dig into her handbag and tried to pull out one of the biggest magnifying glasses (放大镜) I had never seen in my whole life! "Oh, she can't read it," I realized.

    So I stood there and continued watching her. The voice in my mind often asks me to do the right thing. It told me to help her. But I argued back saying, "No. I won't offer help. It will only embarrass her and she is OK now anyway. She has the world's biggest magnifying glass to help her！"

    And I stood there longer. But the voice came back, "Help her, Nicole. Don't be embarrassed. Just do it. Offer your help." So I did it. I read and explained all the things that were included in that box. I read out the ingredients, the instructions on how to cook it and so on.

    She didn't end up buying it, but she was still quite grateful. I walked away knowing that I had helped her and made the right choice. Mostly, I had reminded her that people in this world still care about the old.

    She was seen. She was loved. And she mattered so much that a complete stranger took time to help her. And that stranger was me, a person who argued and didn't want to do so in the beginning.

    So grateful I am when I choose to listen to the voice in my heart. It is because of love. Love is all that ever really matters. I also get happiness through helping her.

I was born legally blind. Of all the stories of my early childhood, the one about a 1 is my mother's favorite. I was only two when the 2 occurred. We had just arrived home from a trip. Mom lifted me out of the car and 3 to speak to the driver. I took advantage of my brief 4 to dash across the lawn (草坪) and hit a large maple tree! I was running so fast that I bounced off the trunk and landed on my backside. Mom 5 me to start crying, but I just sat there for a minute. Then I 6 myself up and kept right on going. 

Mom loves to use this story as an 7 . It reminds her that children don't enter life 8 to take risks or unwilling to 9 again when they fall down. She never wanted me to lose that toughness as I grew older. When I 10 my major life decisions, I was still that little girl tearing full-speed across the lawn. I studied abroad and later moved away from my parents' home to look for a 11 . Through years of 12 , I have become a respected teacher in a school serving high-need students. 

We are almost certain to get 13 at some point during the process of achieving our goal. When that happens, don't sit in the grass and 14 . Just get up and keep on going. It will all be worth it 15 .