Diesel fuel // in general is any liquid fuel used in diesel engines. The most common is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel, are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is increasingly called petrodiesel. Ultra-low-sulfur diesel (ULSD) is a standard for defining diesel fuel with substantially lowered sulfur contents. As of 2007, almost all diesel fuel available in the United States of America, Canada and Europe is the ULSD type.
In the UK, diesel fuel for on-road use is commonly abbreviated DERV, standing for Diesel Engined Road Vehicle, which carries a tax premium over equivalent fuel for non-road use (see Taxation). In Australia Diesel fuel is often known as 'distillate'
Petroleum products are useful materials derived from crude oil (petroleum) as it is processed in oil refineries. Unlike petrochemicals, which are a collection of well-defined usually pure chemical compounds, petroleum products are complex mixtures. The majority of petroleum is converted to petroleum products, which includes several classes of fuels.
According to the composition of the crude oil and depending on the demands of the market, refineries can produce different shares of petroleum products. The largest share of oil products is used as "energy carriers", i.e. various grades of fuel oil and gasoline. These fuels include or can be blended to give gasoline, jet fuel, diesel fuel, heating oil, and heavier fuel oils. Heavier (less volatile) fractions can also be used to produce asphalt, tar, paraffin wax, lubricating and other heavy oils. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials. Since petroleum often contains a few percent sulfur-containing molecules, elemental sulfur is also often produced as a petroleum product. Carbon, in the form of petroleum coke, and hydrogen may also be produced as petroleum products. The hydrogen produced is often used as an intermediate product for other oil refinery processes such as hydrocracking and hydrodesulfurization.
A diesel engine (also known as a compression-ignition engine) is an internal combustion engine that uses the heat of compression to initiate ignition and burn the fuel that has been injected into the combustion chamber. This contrasts with spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to gasoline), which use a spark plug to ignite an air-fuel mixture. The engine was developed by German inventor Rudolf Diesel in 1893.
The diesel engine has the highest thermal efficiency of any standard internal or external combustion engine due to its very high compression ratio. Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) can have a thermal efficiency that exceeds 50%.
Energy economics is a broad scientific subject area which includes topics related to supply and use of energy in societies. Due to diversity of issues and methods applied and shared with a number of academic disciplines, energy economics does not present itself as a self-contained academic discipline, but it is an applied subdiscipline of economics. From the list of main topics of economics, some relate strongly to energy economics:
Energy economics also draws heavily on results of energy engineering, geology, political sciences, ecology etc. Recent focus of energy economics includes the following issues:
Transport economics is a branch of economics founded in 1959 by American economist John R. Meyer that deals with the allocation of resources within the transport sector. It has strong links to civil engineering. Transport economics differs from some other branches of economics in that the assumption of a spaceless, instantaneous economy does not hold. People and goods flow over networks at certain speeds. Demands peak. Advance ticket purchase is often induced by lower fares. The networks themselves may or may not be competitive. A single trip (the final good, in the consumer's eyes) may require the bundling of services provided by several firms, agencies and modes.
Although transport systems follow the same supply and demand theory as other industries, the complications of network effects and choices between dissimilar goods (e.g. car and bus travel) make estimating the demand for transportation facilities difficult. The development of models to estimate the likely choices between the such goods involved in transport decisions (discrete choice models) led to the development of an important branch of econometrics, as well as a Nobel Prize for Daniel McFadden.
Energy conservation refers to reducing energy through using less of an energy service. Energy conservation differs from efficient energy use, which refers to using less energy for a constant service. For example, driving less is an example of energy conservation. Driving the same amount with a higher mileage vehicle is an example of energy efficiency. Energy conservation and efficiency are both energy reduction techniques.
Even though energy conservation reduces energy services, it can result in increased financial capital, environmental quality, national security, and personal financial security. It is at the top of the sustainable energy hierarchy.]citation needed[
Gasoline gallon equivalent (GGE) or gasoline-equivalent gallon (GEG) is the amount of alternative fuel it takes to equal the energy content of one liquid gallon of gasoline. In 1994, the U.S. National Institute of Standards and Technology or NIST defined "gasoline gallon equivalent (GGE) means 5.660 pounds of natural gas."
GGE allows consumers to compare the energy content of competing fuels against a commonly known fuel—gasoline. Compressed natural gas (CNG), for example, is a gas rather than a liquid. It can be measured by its volume in Standard cubic feet (ft³) (volume at atmospheric conditions), by its weight in pounds (lb) or by its energy content in joules (J) or British thermal units (BTU) or kilowatt-hours (kW·h). It is difficult to compare the cost of gasoline with other fuels if they are sold in different units. GGE solves this. A GGE of CNG and a GGE of electricity all have the same energy content as one gallon of gasoline. CNG sold at filling stations is priced in dollars per GGE.
In journalism, a human interest story is a feature story that discusses a person or people in an emotional way. It presents people and their problems, concerns, or achievements in a way that brings about interest, sympathy or motivation in the reader or viewer.
Human interest stories may be "the story behind the story" about an event, organization, or otherwise faceless historical happening, such as about the life of an individual soldier during wartime, an interview with a survivor of a natural disaster, a random act of kindness or profile of someone known for a career achievement.