Thermoacoustic (TA) heat engines are engines which convert heat into acoustic power. This relatively new class of heat engines gains commercial interest, because of their low number of moving parts and high potential efficiency [1]. Especially traveling wave thermoacoustic engines are capable of reaching this high efficiency, because traveling wave engines perform a thermodynamic cycle similar ...

Electricity was born at the dawn of the last century. Households were inundated with a ßood of new consumer durables. What was the impact of this consumer durable goods revolution? It is argued here that the consumer goods revolution was conducive to liberating women from the home. To analyze this hypothesis, a Beckerian model of household production is developed. Households must decide whether...

The World Wide Web has become the largest information source in recent years and search engines are indispensable tools for finding needed information from the Web. The coverage of the Web by a single search engine may be limited. One effective way to increase the search coverage of the Web is to combine the coverage of multiple search engines. Systems that do such combination are called metase...

Compares the searching capabilities of two search engines (Google and Yahoo) and two metasearch engines (Metacrawler and Dogpile) on the basis of the precision value and relative recall. Fifteen queries which represented a broad range of library and information science topics were selected and each query was submitted to the search engines and metasearch engines. The first 100 results in each s...