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ABS - Acrylonitrile Butadiene Styrene - A common thermoplastic used in a wide variety of everyday products. Solvents will damage ABS. It has some resistance to most chemicals (except strong oxidizers) It has good strength and crack resistance.

Acetic Acid - An acid with the structure of C2H4O2. Acetyl groups are bound through an ester linkage to hemicellulose chains, especially xylan, in wood and other plants. The natural moisture present in plants hydrolyzes the acetyl groups to acetic acid, particularly at elevated temperatures.

Acetone - Chemical Formula: C3H6O - (also known as propanone, dimethyl ketone, 2-propanone, propan-2-one and beta-ketopropane) A solvent used in the soap test. It is the active ingredient in fingernail polish remover. It is the simplest form of a ketone.

Acid - Any of a class of substances whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals to form salts. A substance that yields hydrogen ions when dissolved in water. A substance that can act as a proton donor.

Acid Detergent Fiber (ADF) - Organic matter that is not solubilized after 1 hour of refluxing in an acid detergent of cetyltrimethylammonium bromide in 1N sulfuric acid. ADF includes cellulose and lignin. This analytical method is commonly used in the feed and fiber industries.
Acid Esterification - A common approach for removing free fatty acids from the feedstock is via acid catalyzed esterfication in the presence of methanol. This converts the free fatty acids to methyl esters (e.g., biodiesel). Acid esterfication equipment requires the use of stainless steel equipment due to the corrosive nature of the process.

Acid Hydrolysis - A chemical process in which acid is used to convert carbohydrate or starch to monomer sugars.

Acid Insoluble Lignin - Lignin is mostly insoluble in mineral acids, and therefore can be analyzed gravimetrically after hydrolyzing the cellulose and hemicellulose fractions of the biomass with sulfuric acid. ASTM E-1721-95 describes the standard method for determining acid insoluble lignin in biomass.

Acid Number - In biodiesel it is the results of ASTM D 664. It is a titration test on finished biodiesel that is a direct measure of free fatty acids. Over time, as biodiesel degrades, the Acid number will increase.

Acid Soluble Lignin - A small fraction of the lignin in a biomass sample is solubilized during the hydrolysis process of the acid insoluble lignin method. This lignin fraction is referred to as acid soluble lignin and may be quantified my ultraviolet spectroscopy.

Advanced Biofuels - These are biofuels manufactured from more sustainable feedstocks using advanced processing technology resulting in more efficient utilisation of the feedstock and lower CO2 emissions. One of the key benefits of advanced biofuels is that they will be manufactured from, for example, non-food crops such as lignocellulosic biomass. The use of lignocellulose opens the way for biofuels to be manufactured from a much wider range of feedstocks in future, therefore increasing the overall supply potential for biofuels worldwide.

Advantaged molecule biofuels - These are the next generation biofuel products such as bio-butanol. Versus first generation biofuels, advantaged products offer better fuel characteristics with less need for vehicle modifications for use.

Additives - Chemicals added to fuel in very small quantities to improve and maintain fuel quality. Detergents and corrosion inhibitors are examples of gasoline additives.
Advanced Technology Vehicle (ATV) - A vehicle that combines new engine/power/drivetrain systems to significantly improve fuel economy. This includes hybrid power systems and fuel cells, as well as some specialized electric vehicles.

Aerosol - A dispersion of a liquid or solid in a gas.

Aftermarket - Broad term that applies to any change after the original purchase, such as adding equipment. When applied to AFVs, it refers to conversion devices or kits for conventional fuel vehicles.

AGE 85 - Aviation Grade Ethanol used in piston engine aircraft. This fuel contains 85% Ethanol along with light hydrocarbons and biodiesel fuel.

Agitator - A device such as a stirrer that provides complete mixing and uniform dispersion of all components in a mixture. Agitators are generally used continuously during the cooking process and intermittently during fermentation.

Agricultural Residue - Agricultural crop residues are the plant parts, primarily stalks and leaves, not removed from the fields with the primary food or fiber product. Examples include corn stover, stalks, leaves, husks, and cobs); wheat straw; and rice straw.

Agro-Energy - Energy derived from purposely-grown crops, and from agricultural and livestock by-products, residues and wastes.

Air Quality Management District (AQMD) - A term used principally in California to describe administrative districts organized to control air pollution. Nationwide, AQMDs are parallel to the areas designated for classification against the National Ambient Air Quality Standards (NAAQS). Generally, AQMDs and their national parallel encompass multiple jurisdictions and closely follow the definition of Consolidated Metropolitan Statistical Areas and Metropolitan Statistical Areas.

Air Quality Maintenance Area - Specific populates area where air quality is a problem for one or more pollutants.

Air Toxics - Toxic air pollutants defined under Title II of the CAA, including benzene, formaldehyde, acetaldehyde, 1-3 butadiene, and polycyclic organic matter (POM). Benzene is a constituent of motor vehicle exhaust, evaporative, and fueling emissions. The other compounds are exhaust pollutants.

Alcohol - A general class of hydrocarbons that contain a hydroxyl group (OH). The term "alcohol" is often used interchangeably with the term "ethanol," even though there are many types of alcohol. (See Butanol, Ethanol, Methanol.)

Aldehydes - A class of organic compounds derived by removing the hydrogen atoms from an alcohol. Aldehydes can be produced from the oxidation of an alcohol.

Aldoses - Occur when the carbonyl group of a monosaccharide is an aldehyde.

Algae - Primitive plants, usually aquatic, capable of synthesizing their own food by photosynthesis. Algae is currently being investigated as a possible feedstock for production in biodiesel, jet fuel, and other bioproducts.

Algaculture - A term used to describe the farming of algae using aquaculture. Certain algae species contain large quantities of lipids (fatty oils) that may potentially be used as a viable and easily sustainable feedstock for the production of biodiesel. Many species of algae replicate quickly and form dense colonies which theoretically can yield more energy per acre than any other feasible crop feedstock. The algae can also be used to clean wastewater and feed livestock, maximizing the environmental benefit. Algae farming has been studied intensively in the last 30 years, but production cost, species sustainability, and large-scale production remain as barriers to its current use in commercial manufacture.

Aliphatic - Any non-aromatic organic compound having an open chain structure.

Alkali - A soluble mineral salt with pH greater than 7.0 in aqueous solution such as NaOH, KOH.

Alkali Lignin - Lignin obtained by acidification of an alkaline extract of wood.

Alkali Solution - In biodiesel production, an Alkali solution is used as the reagent in titration. It is made by mixing catalyst either, KOH or NaOH, with water in prescribed ratios.

Alkylation - A refining process for converting light, gaseous olefins into high-octane gasoline components.

Alloy - Any large number of substances having metallic properties and consisting of two or more elements; with few exceptions, the components are usually metallic elements.

Alternative Fuel - As defined in the Energy Policy Act of 1992 (EPACT): methanol, denatured ethanol and other alcohols, separately or in blends of at least 10% by volume with gasoline or other fuels; compressed natural gas; liquefied natural gas, liquefied propane gas, hydrogen, coal derived liquid fuels, fuels other than alcohols derived from biological materials, electricity, biodiesel, and any other fuel deemed to be substantially not petroleum and yielding potential energy security benefits and substantial environmental benefits.

Alternative Fuel Provider - A fuel provider (or any affiliate or business unit under its control) is an alternative fuel provider if its principal business is producing, storing, refining, processing, transporting, distributing, importing, or selling (at wholesale or retail) any alternative fuel (other than electricity); or generating, transmitting, importing, or selling (at wholesale and retail) electricity; or if that fuel provider produces, imports, or produces and imports (in combination), an average of 50,000 barrels per day of petroleum and 30% (a substantial portion) or more of its gross annual revenues are derived from producing alternative fuels.

Alternative Fuel Vehicle (AFV) - As defined by the Energy Policy Act, any dedicated, flexible-fuel, or dual-fuel vehicle designed to operate on at least one alternative fuel.

Alternative Fuels Data Center (AFDC) - A program sponsored by DOE and managed by the National Renewable Energy Laboratory to collect data and information on all types of Alternative Fuels and AFVs across the country.

Alternative Fuels Utilization Program (AFUP) - A program managed by DOE with the goals of improving national energy security by displacing imported oil, improving air quality by development and widespread use of alternative fuels for transportation, and increasing the production of AFVs.

Alternative Motor Fuels Act of 1988 (AMFA) - Public Law 100-494. Encourages the development, production and demonstration of alternative motor fuels and AFVs. Ambient Air Quality - The condition of the air in the surrounding environment.

American Society for Testing and Materials (ASTM)- A nonprofit organization that provides a management system to develop published technical information. ASTM standards, test methods, specifications, and procedures are recognized as definitive guidelines for motor fuel quality as well as a broad range of other products and procedures.

Anaerobic - Life or biological processes that occur in the absence of oxygen.

Anaerobic Digestion - A biochemical process by which organic matter is decomposed by micro-organisms such as bacteria in the absence of oxygen, producing a gas comprising mostly methane and carbon dioxide.

Anhydrous - Describes a compound that does not contain any water. Ethanol produced for fuel use is often referred to as anhydrous ethanol, as it has had almost all water removed.

Annual Removals - The net volume of growing stock trees removed from the inventory during a specified year by harvesting, cultural operations such as timber stand improvement, or land clearing.

Aquatic Plants - The wide variety of aquatic biomass resources, such a algae, giant kelp, other seaweed, and water hyacinth. Certain microalgae can produce hydrogen and oxygen while others manufacture hydrocarbons and a host of other products. Microalgae examples include Chlorella, Dunaliella, and Euglena.

Arabinan - The polymer of arabinose with a repeating unit of C5H804. Can be hydrolyzed to arabinose.

Arabinose - A five-carbon sugar C5H1005. A product of hydrolysis of arabinan found in the hemicellulose fraction of biomass.

Aromatics - Hydrocarbons based on the ringed six-carbon benzene series or related organic groups. Benzene, toluene and xylene are the principal aromatics, commonly referred to as the BTX group. They represent one of the heaviest fractions in gasoline. Aromatics have strong, characteristic odors.

Asexual Reproduction - the naturally occurring ability of some plant species to reproduce asexually through seeds, meaning the embryos develop without a male gamete. This ensures the seeds will produce plants identical to the mother plant.

ASTM specifications - Standards created for commercial fuels. ASTM's "Standard Specifications for Biodiesel Fuel (B100) Blending Stock for Distillation Fuels," D6751-02, includes results and measurable fuel qualities as well as testing methods.

Atmospheric Pressure - Pressure of the air and atmosphere surrounding us which changed from day to day. It is equal to 14.7 psia.

Attainment Area - A geographic region where the concentration of a specific air pollutant does not exceed federal standards.

Auger - A rotating, screw-type service that moves material through a cylinder.

Autoignition Temperature - The temperature at which a substance will ignite and burn without a spark or other ignition source.

Available Production Capacity - The biodiesel production capacity of refining facilities that are not specifically designed to produce biodiesel.

Average Megawatt - (MWa or aMW) One megawatt of capacity produced continuously over a period of one year. 1aMW = 1MW x 8760 hours/year = 8,760 MWh = 8,760,000 kWh.

Azeotrope - a mixture of two or more liquids that can to be separated by distillation. Ethanol and water are azeotropic at ethanol to water ratios above 95%. You can not distill the last 5% of the water out of ethanol.