The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Octane rating is a method for describing antiknock properties of gasoline. Knocking is a pinging sound produced by internal combustion engines when fuel ignites prematurely during the engine's compression cycle. Because knocking can damage an engine and rob it of power, gasoline formulations have been developed to minimize the problem. Gasolines containing relatively large amounts of straight-chain hydrocarbons (such as n-heptane) have an increased tendency to knock, whereas those containing branched-chain forms (such as isooctane) burn more smoothly. In addition to isooctane, other compounds also reduce engine knocking. By using an index called octane number, it is possible to compare the antiknock properties of gasoline mixtures. A higher octane number indicates that a mixture has the equivalent antiknock properties of a gasoline containing a higher percentage of isooctane.
Although gasoline used as automotive fuel is now "deleaded," gasoline used as aviation fuel still contains tetraethyl lead as an octane enhancer and antiknock agent.