His latest invention is an electrical generator based on a 19th-century idea-an unusually efficient kind of engine, called a Stirling engine-which never caught on.
他最新的发明是一个以19世纪思想基础上的发电机——一类异常高效的发动机——尽管从未流行起来。
2
Of course you'll still indirectly generate emissions when charging electrical gadgets at home, but it is still more efficient than doing so in a car.
当然在家充电也间接释放气体，但是比在车上充要有效率多了。
3
Hagelstein, an associate professor of electrical engineering at MIT, says existing solid-state devices to convert heat into electricity are not very efficient.