The United States government classification system is currently established under Executive Order 13526, the latest in a long series of executive orders on the topic.[1] Issued by President Barack Obama in 2009, Executive Order 13526 replaced earlier executive orders on the topic and modified the regulations codified to 32 C.F.R. 2001. It lays out the system of classification, declassification, and handling of national security information generated by the U.S. government and its employees and contractors, as well as information received from other governments. An example of a U.S. classified document; page 13 of a United States National Security Agency report on the USS Liberty incident, partially declassified and released to the public in July 2003. The original overall classification of the page, "top secret code word UMBRA, is shown at top and bottom. The classification of individual paragraphs and reference titles is shown in parentheses—there are six different levels on this page alone. Notations with leader lines at top and bottom cite statutory authority for not declassifying certain sections. The desired degree of secrecy about such information is known as its sensitivity. Sensitivity is based upon a calculation of the damage to national security that the release of the information would cause. The United States has three levels of classification: confidential, secret, and top secret. Each level of classification indicates an increasing degree of sensitivity. Thus, if one holds a top secret security clearance, one is allowed to handle information up to the level of top secret, including secret and confidential information. If one holds a secret clearance, one may not then handle top secret information, but may handle secret and confidential classified information. In the United States, a nation without a British-style Official secrets act, the disclosure of classified information is not, in general, illegal, and Congress has repeatedly resisted or failed to pass a law that generally outlaws disclosing classified information. Instead, a 'patchwork' of different laws criminalize only certain types of classified information, and then only under certain circumstances. Most of Espionage Law only criminalizes national defense information; only a jury can decide if a given document meets that criteria, and judges have repeatedly said that being 'classified' doesn't necessarily make information become related to the 'national defense'. Furthermore, by law, information may not be classified merely because it would be embarrassing or to cover illegal activity; information may only be classified to protect national-security objectives.

Gasoline Engines

Gasoline engines have the advantage over diesel in being lighter and able to work at higher rotational speeds and they are the usual choice for fitting in high-performance sports cars. Continuous development of gasoline engines for over a hundred years has produced improvements in efficiency and reduced pollution. The carburetor was used on nearly all road car engines until the 1980s but it was long realized better control of the fuel/air mixture could be achieved with fuel injection. Indirect fuel injection was first used in aircraft engines from 1909, in racing car engines from the 1930s, and road cars from the late 1950s.

Gasoline Direct Injection (GDI) is now starting to appear in production vehicles such as the 2007 BMW MINI. Exhaust gases are also cleaned up by fitting a catalytic converter into the exhaust system. Clean air legislation in many of the car industries most important markets has made both catalysts and fuel injection virtually universal fittings. Most modern gasoline engines are also capable of running with up to 15% ethanol mixed into the gasoline - older vehicles may have seals and hoses that can be harmed by ethanol. With a small amount of redesign, gasoline-powered vehicles can run on ethanol concentrations as high as 85%. 100% ethanol is used in some parts of the world (such as Brazil), but vehicles must be started on pure gasoline and switched over to ethanol once the engine is running. Most gasoline engines cars can also run on LPG with the addition of an LPG tank for fuel storage and carburetion modifications to add an LPG mixer. LPG produces fewer toxic emissions and is a popular fuel for fork lift trucks that have to operate inside buildings.