First-Class MailÂ® is a fast, affordable way to send envelopes and lightweight packages. Itâs perfect for business and personal correspondence, cards, brochures, and lightweight merchandise. The First-Class Mail ForeverÂ® Stamp price is $0.49; First-Class Mail Postcard Stamp price is $0.34.
Architecture of a metasearch engine. A metasearch engine (or aggregator) is a search tool that uses another search engine's data to produce their own results from the Internet. Metasearch engines take input from a user and simultaneously send out queries to third party search engines for results. Sufficient data is gathered, formatted by their ranks and presented to the users.
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be used.