Sherry Laboratories provides independent and uniquely accredited materials, environmental, food and microbiological, and petrochemical testing services, engineering expertise, technical services and products of the highest quality in a cost-effective and timely manner for the success of our clients.
ENVIRONMENTAL and MICROBIOLOGICAL TESTING
Actinomycetes – a large group of mold-like microorganisms which give off an odor characteristic of rich earth and are the significant organisms involved in the stabilization of solid wastes by composting.
Adsorption – Removal of a pollutant from air or water by collecting the pollutant on the surface of a solid material; e.g., an advanced method of treating waste in which activated carbon removes organic matter from waste-water.
Aerobic Bacteria – bacteria that can grow only in the presence of free or atmospheric oxygen.
Aerobic Plate Count – this test is used to determine the total number of anaerobic bacteria (requiring no oxygen) present at mesophyllic temperatures (30° C-37° C). Organisms included in this group are Clostridium perfringens and Clostridium bochulinum. Both of these are pathogens (organisms capable of causing illness). Other bacteria are also anaerobic and can cause spoilage problems in Modified Atmosphere Packaging. Most pathogens are facultative anaerobes and may show up on this test as well. Detailed procedures for determining the APC of foods have been developed by the Association of Official Analytical Chemists (AOAC, 1990) and the American Public Health Association (APHA, 1984).
Agar – a gelatinous product extracted from certain algae and used chiefly as a gelling agent in culture media.
Agar-Gel Reaction – a precipitin type of antigen-antibody reaction in which the reactants are introduced into different regions of an agar gel and allowed to diffuse toward each other.
Agar Plate Count – the number of bacterial colonies that develop on a medium in a petri dish seeded with a known amount of inoculum.
Algae – primitive organisms that contain chlorophyll and carry on photosynthesis but lack true roots, stems, and leaves. While historically considered plants, many algae are now classified in the kingdoms Monera and Protista. They are abundant both in the sea and freshwater Algae occur as microscopic single cells and more complex forms of many cells grouped in spherical colonies, in ribbonlike filament, and in giant forms (e.g., the marine kelps). The cells of colonies are generally similar, but some are specialized for reproduction and other functions. The blue-green algae (cyanobacteria) and green algae include most of the freshwater forms, such as pond scum, a green slime found in stagnant water. Brown and red algae are more complex, chiefly marine forms whose green chlorophyll is masked by the presence of other pigments. Algae are primary food producers in the food chain and also provide oxygen for aquatic life. Algae that thrive in polluted water can over-multiply, resulting in an algal bloom and seriously unbalancing their ecosystem.
Anaerobic Bacteria – bacteria which cannot grow in the presence of free or atmospheric oxygen.
Anderson Sampler – an aerosol sampling device consisting of a series of stacked stages and collection surfaces. It determines the particle size distribution of a gas sample containing particulates.
Antibiotic Screening – a method for quantitatively determining the concentration of an antibiotic by its effect in inhibiting the growth of a susceptible microorganism.
Atomic Absorption (AA) – instrumentation used to determine metal content in samples. Elements are identified by their characteristic absorption of specific wavelength radiation. Vaporization of samples is generally accomplished by various methods, including FLAME and FURNACE. The COLD VAPOR system is used for Mercury vaporization. This technique can analyze only one element at a time, depending on which specific wavelength filter is being used. Often, but not always, it can quantify lower concentrations of metals than can be determined by Inductively Coupled Plasma (ICP).
Bacillus SPP. – a gram-positive, aerobic spore-forming bacteria. It occurs widely in nature and in soil. It forms large spores. Bacterial spores are highly resistant to all forms of food processing techniques that normally kill vegetative cells. Bacillus possesses a wide range of physiologic activities, including fermentation of sugar, peptonization of protein, hydrolysis of starch and rennin coagulation of milk.
Bacteria – unicellular, generally microscopic organisms having three typical forms: rod-shaped (bacillus), round (coccus), and spiral (spirillum). The cytoplasm of most bacteria – the oldest life-forms on earth – is surrounded by a cell wall; the nucleus contains DNA but lacks the nuclear membrane found in higher plants and animals. Many forms are motile, propelled by movements of a filament-like appendage (flagellum). Reproduction is chiefly by transverse fission (mitosis), but conjugation (transfer of nucleic acid between two cells) and other forms of genetic recombination also occur. Some bacteria (aerobes) can grow only in the presence of free or atmospheric oxygen; others (anaerobes) cannot grow in its presence; and a third group (facultative anaerobes) can grow with or without it. In unfavorable conditions, many species form resistant spores. Bacteria are both useful and harmful to humans. Some are used for soil enrichment with leguminous plants, in alcohol and cheese fermentation, and to decompose organic wastes and clean up toxic waste sites. Others – called pathogens – cause a number of plant and animal diseases, including cholera, diarrhea, syphilis, typhoid fever, and tetanus.
Bacterial Challenge Testing – a procedure frequently used by the food industry to determine the limits of stability, to assess the risk of food poisoning of a product, and to determine which components of a food are responsible for its preservation. It can be defined as the laboratory simulation of what can happen to a product during manufacture, distribution, and subsequent handling. In it simplest form, challenge testing can involve the storage of product, or different formulations of a product, under realistic and obtuse conditions, as is used in determining shelf life. Microbiological challenge testing involved the inoculation of a product with relevant microorganisms and/or holding the product under a range of controlled environmental conditions. As such, challenge testing provides information on the conditions that allow/inhibit growth of a particular microorganism, but it does not provide information on the likelihood of organisms being present in the product. An essential part of designing a challenge test is therefore the choice of relevant organisms used to inoculate the product. These should be those with known tolerance to the food and storage conditions and therefore likely to cause spoilage or food poisoning in the product under test.
Benzene, Toluene, Ethylbenzene and Xylene (BTEX) Analysis – an analysis performed by gas chromatograph for Benzene, Toluene, Ethylbenzene and xylene. The presence of all four of these organic compounds indicates the presence of gasoline.
Biochemical Oxygen Demand (BOD) – the amount of oxygen required for aerobic bacteria to completely oxidize the organic matter within a specified time and at a given temperature – an index to the degree of organic pollution in the water. When discharged to a watercourse, waste containing BOD constituents will consume dissolved oxygen in the water; the BOD indicates the rate at which the oxygen is used up. Waters that receive high BOD waste undergo reduction of oxygen and subsequent damage to aquatic life; a measure of the amount of oxygen consumed in the biological processes that break down organic matter in water. The greater the BOD, the greater the degree of pollution.
Biocides – a chemical toxic to a biological life; a compound that has the ability to inactivate microorganisms. In a general term, biocide refers to compounds that can be used as an algicide (inactivate algae), bactericide (inactivate bacteria), fungicide (inactivate fungi), and viricide (inactivate viruses), or some combination of the above. It is equivalent to disinfectant.
Biodegradation – capable of being broken down especially into harmless products by the action of living things (as microorganisms).
Bioremediation – the treatment of pollutants or waste (as in an oil spill, contaminated groundwater, or industrial process) by the use of microorganisms (as bacteria) that break down the undesirable substances.
BTEX Analysis – see Benzene, Toluene, Ehtylbenzene and xylene analysis.
Campylobacter Spp. – a genus of gram-negative microaerophilic or anaerobic, chemoorganotrophic bacteria of the Spirillaceae (a family of helical bacteria in which each cell forms an incomplete turn of a helix, or a number of turns, depending on the species; the cells are rigid and are polarly flagellate); species occur in the mouth, alimentary tract and reproductive organs in man and other animals. The cells are nonpigmented, less than 1 micron in diameter and about 1-5 microns in length; a single flagellum is carried at one or at each pole of the cell – the organism moving with a corkscrew-like motion.
Chemical Analysis – the determination of chemical structure and chemically active species in a subject. It involves both direct measurements and use of specific compounds to achieve selective reactions of a component of the substance being analyzed; to produce a readily measurable species; or to determine a reactive end product. Detection may involve simple visual or optical observations, recording of an electrical or thermal response, or use of sophisticated spectroscopic or other complex automated instrumentation with computerized controls and data handling capabilities.
Clean Air Act (CAA) – the legislative basis for air pollution control regulations. It was first enacted in 1955 and later amended in 1963, 1965, 1970, 1977 and 1990. The 1955 Act and the 1963 Amendments called for the abatement of air pollution through voluntary measures. The 1965 Amendment gave federal regulators the authority to establish automobile emission standards. The 1970 Amendments broadened the scope of the original Act and formed the basis for federal and state air pollution control regulations. The 1990 Amendments significantly expanded the scope of the Act, including listing 189 hazardous air pollutants. It required the Environmental Protection Agency to start setting standards for categories of sources that emit those pollutants within two years (1992) and finish setting all standards within 10 years (2000). The CAA requires the EPA to identify each substance that it believes causes or contributes to air pollution. Further, the EPA must identify each substance that it reasonably believes endangers public health or welfare.
Clean Water Act (CWA) – the Environmental Protection Agency established national water quality goals under this legislation. Water pollution from industrial and municipal facilities is controlled primarily through permits limiting discharges. Permit limits are based on effluent guidelines for specific pollutants, performance requirements for new sources, and/or water quality limits. Permits also set schedules and timetables for construction and installation of needed equipment. Sources which discharge indirectly to a municipal treatment plant are subject to pretreatment standards. Other key provisions of the CWA require permits for discharge of dredged and fill materials into waters (including wetlands), and requirements for reporting and cleaning up spills of oil or hazardous material. This act was originally enacted as the Federal Water Pollution Control Act Amendments of 1972
Clostridium Spp. – a genus of spore-forming chemoorganotrophic, obligately anaerobic (or aerotolerant), pleomorphic rod-shaped bacteria of the family Bacillaceae (a family of spore-forming bacteria comprising the genera bacillus, clostridium, desulphotomaculum, sporolactobacillus and sporosarcina). The organisms are typically gram-positive, motile and catalase-negative. Clostridium spp are widespread in soil, muds, etc., and in the intestinal tract of animals, including man. Diseases caused by Clostridium spp include botulism, gas gangrene, tetanus, blackleg and braxy.
Coagulation – the process of adding chemicals such as aluminum sulfate, ferric chloride, or polyelectrolytes to wastewater. This causes the surface characteristics of the suspended solids to be altered so that they attach to one another and precipitate. Flocculation causes the suspended solids to coalesce. Coagulation and flocculation can remove more than 80 percent of suspended solids.
Coliforms – gram negative organisms capable of fermenting lactose. Coliforms are common environmental organisms and may be found in soil, on hands, on equipment surfaces, in water, etc. Coliform tests, as a group, are used as an overall indication of sanitation efficiency. Most coliforms are not harmful (pathogenic), but if a coliform test indicates their presence, it is considered to be an indication of unsanitary conditions. There are no standards for coliforms for most foods. Many Product Specifications are written with a zero or low tolerance for coliforms.
Coliform Counts – Escherichia coli, E. Coli for short, are professionally known as coliforms. While these bacteria are harmless to humans, their presence in a water sample indicates human and mammalian excreta. This could signal the presence of pathogens. And the nonpathogenic coliforms are used to determine the safety of the water in question. If the coliform count in the sample is high, the water is unsafe for drinking, but may possibly be used for other purposes. Drinking water should have a coliform count of zero. Higher counts are permissible for fishing, boating, etc.
Coliphage – any bacteriophage whose host is a strain of E. coli.
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) – enacted federal legislation that regulates the cleanup of hazardous waste sites. Programs regulated by this legislation are also known as the Superfund Program because of the fund created to finance cleanups of hazardous waste sites where no responsible parties can be found. The CERCLA was enacted in 1980 as an amendment to the Solid Waste Disposal Act, the predecessor statute to RCRA. The CERCLA focuses on the cleanup of hazardous waste by (1) establishing an information-gathering and analysis system to characterize site contamination, assess risks and develop cleanup actions; (2) providing for a national inventory of inactive hazardous waste sites; and (3) establishing a program designed to respond to the dangers of spills from such sites.
Contaminants – any physical, chemical, biological, or radiological substance or matter that has an adverse affect on air, water, or soil.
Corrosion – the quality of a substance which causes the gradual deterioration of another material by chemical processes, such as oxidation or attack by acids; emissions containing corrosive substances that are by-products of combustion can cause rusting and other forms of corrosion among metal structures. The most prevalent corrosive agents include the oxides of sulfur, such as SO3, which is present in small quantities when large quantities of SO2 are generated by combustion and combinations of chlorine, fluorine. It is difficult to estimate how much damage airborne corrosives cause. Corrosion is also caused by liquids containing corrosive agents.
Critical Control Points – when assessing the potential hazards associated with all stages of the food manufacturing process, that stage of the process that needs to be controlled to assure safety (or product stability).
Discharge Monitoring – activities involved with monitoring actual discharge, which is a catchall term that pertains to any pollutant introduced into the environment. Normally, gaseous discharges are called emissions, while liquid discharges are called effluents. Solid wastes, in more candid fashion, are called discharges.
Effluent – The liquid, solid or gaseous wastes discharged by a process, treated or untreated.
Enterococci – a group of cocci (sphere-shaped bacteria) having its normal habitat in the intestines of man or animals.
Enterotoxin – a toxin that is produced by microorganisms (as some staphylococci) and causes gastrointestinal symptoms (as in some forms of food poisoning or cholera).
Environmental Audit – an independent assessment of the current status of a party’s compliance with applicable environmental requirements or of a party’s environmental compliance policies, practices and controls.
Escherichia Coli (E. Coli) – common bacterium that normally inhabits the intestinal tracts of humans and animals but can cause infection in other parts of the body, especially the urinary tract. One strain, sometimes transmitted in hamburger meat, can cause serious infection resulting in diarrhea, anemia, kidney failure, and death. E. coli are a subgroup of the coliform group. They are the most numerous coliform species and most are considered nonpathogenic (normally not able to cause illness). The presence of E. coli in foods is considered to be an indication of fecal contamination. Most Product Specifications are written with a zero tolerance for E. coli. Some E. coli are pathogenic, most notably, E. coli O157, which has been linked to several deaths and thousands of cases of food poisoning.
FacultativeM – having the ability to live and adapt to various conditions while not being restricted to those conditions or mode of life, such as bacteria that can live either with or without oxygen.
Fecal Coliform – bacteria from excrement, fecal coliform are not necessarily harmful by themselves, but are indicative of the presence of other disease-causing organisms that may cause diarrhea, vomiting, or a more serious illness.
Fecal Streptococci – often used interchangeably with enterococci, but should indicate only one group of streptococci included in the total enterococci group.
Ferrous Ammonium Sulfate – light-green, water-soluble crystals used in medicine, analytical chemistry and metallurgy. Also known as iron ammonium sulfate and Mohr’s salt.
Field Testing – a nonformal experiment, that is, one with fewer controls than a laboratory experiment; conducted under field conditions.
Fluorescent Stain – the use of fluorescent dyes to mark specific cell structures, such as chromosomes.
Food Microbiology – the study of all aspects of microbial action on food and food products, both directly and indirectly, related to the welfare of mankind.
Fresh Water Analysis – water that generally contains less than 1,000 milligrams-per-liter of dissolved solids.
Fuel Fingerprint – gas chromatograph analysis of a fuel to identify its source by comparison with fingerprints of fuels from known sources.
Fungi – any of a major group of saprophytic (obtaining food by absorbing dissolved organic material) and parasitic spore-producing organisms usually classified as plants that lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts.
Gas Chromatography – instrumentation that uses a solid-phase packed column, with gas as a mobile phase, to separate organic compounds in a mixture. The compounds can be detected as they exit the bottom end of the column with a variety of detectors. Common detection systems include Photoionization Detectors (PIDs), Electron Capture Detectors (ECDs) and Mass Spectroscopy (MS).
Gram Stain – An important method for staining bacteria developed by Christian Gram in 1884. The bacteria are placed as a smear on a slide, then air-dried, then stained first with crystal violet dye and then with Gram’s iodine. The bacteria are then washed with 95% ethanol, flooded with safranin or fuchsin (red dyes) and air-dried again. If the bacteria retain the purple-blue stain on their cell walls, they’re classified as Gram-positive; if they don’t retain the crystal violet but take the red counterstain, they’re Gram-negative. This classification is important because the reaction to Gram stain correlates in many cases with the bacteria’s vulnerability to certain antibiotics. The process only takes a few minutes, making it ideal for medical clinics. If a clinician considers data from the Gram stain along with his/her medical examination of a sick patient, the clinician can get a pretty good idea of the pathogen that is infecting the patient and then start a regimen of antibiotics. In a clinical setting, the Gram stain is followed up by a bacterial culture (which takes three to six days to complete).
Graphite Furnace Atomic Absorption Spectrometry (GFAAS) – the electronically heated graphite furnace gradually heats the sample in several stages. Thus, the processes of desolvation, drying, decomposition of organic and inorganic molecules and salts, and formation of atoms which must occur in a flame or ICP in a few milliseconds may be allowed to occur over a much longer time period and at controlled temperatures In the furnace. This allows an experienced analyst to remove unwanted matrix components (the material in which the substance whose presence is being determined) by using temperature programming and/or matrix modifiers. The major advantage of this technique is that it affords extremely low detection limits. It is the easiest to perform on relatively clean samples.
Ground Water – water from a well or underground aquifer (An underground body of water that is more protected from contaminants than surface water, but is still susceptible to perils such as fecal coliform from septic tanks. Half of all Americans get drinking water from such underground sources. Of these, roughly a third have their own wells, which are not regulated by government. The remainder use municipal water systems, which draw on underground supplies that are subject to the same rules as surface water.
Hazard Analysis Critical Control Point (HACCP) – During the 1960s, the Pillsbury Corporation, with the National Aeronautics and Space Administration and the U.S. Army, adopted the concept of Hazard Analysis Critical Control Point to assure food safety for the U.S. space program. Since that time, the concept has gained wide acceptance for use in the food industry in the United States and Europe. HACCP is a structured approach to the identification and control of hazards and provides a more structured and critical approach than traditional inspection and quality-control procedures. The emphasis is removed from final product testing to the control of raw materials and process operations within the factory environment. The system is proactive and has the potential to identify areas of concern where failure has not yet been experienced and is therefore particularly useful for new operations. Although widely used for food-poisoning hazards, analysis can be made for other hazards such as foreign bodies or chemical contaminants or for spoilage problems or control of waste. The HACCP approach consists of describing assessment of potential hazards associated with all stages of the food manufacturing operation from acquisition of raw material through to product sale and consumption.
Halophilic Microorganisms – those organisms whose requirement for salt – as an environmental factor – exceeds that of other organisms; extreme halophiles require salt concentrations of at least 15 to 20 percent for growth.
Hazard Analysis – the procedures involved in:
- Identifying potential sources of release of hazardous materials from fixed facilities or transportation accidents;
- Determining the vulnerability of a geographical area to a release of hazardous materials; and
- Comparing hazards to determine which present greater or lesser risks to a community.
Hazardous Waste – solid waste (essentially any discarded or abandoned material not excluded from regulation by the Resource Conservation and Recovery Act) that either exhibits characteristics of hazardous waste, including ignitability, corrosivity, reactivity or toxicity; or which has been placed on a specific list of hazardous wastes, such as various spent solvents, industrial sludges and discarded commercial chemical products that are always considered hazardous. The Environmental Protection Agency publishes the list annually in the Code of Federal Regulations.
Hazardous Waste Characterization – characterization of a waste for ignitability, corrosivity and reactivity. A characteristic waste is one that fails RCRA criteria for any one of these tests.
Helminth – a parasitic worm (as a tapeworm, liver fluke, ascarid, or leech); especially : an intestinal worm.
Herbicide – a chemical agent that destroys or inhibits plant growth.
Hydrogen Sulfide – a poisonous gas with the odor of rotten eggs that is produced from the putrefaction of sulfur-containing organic material. Odorous in concentrations as small as parts per billion; gas emitted during organic decomposition. Also a by-product of oil refining and burning. Smells like rotten eggs and, in heavy concentration, can kill or cause illness.
Inductively Coupled Plasma (ICP) – instrumentation used to determine metal content in samples. Elements are identified by their characteristic emissions of specific wavelength radiation produced by a radio-frequency inductively coupled plasma. This technique can analyze multiple elements simultaneously or sequentially.
Industrial Pretreatment – activities involved with assisting industries with monitoring pretreatment processes to effectively manage regulated pollutants.
Industrial Waste – waste materials generally discarded from industrial operations or derived from manufacturing processes; may be liquid, sludge or solid wastes and need not by hazardous.
Influent – an influent is the reverse of an effluent. Since effluent is normally applied to liquids – and mainly to water or water containing colloids and suspended solids, influent can be considered water entering any treatment or processing plant. It generally contains the raw contaminants or pollutants. But when polluted water enters a receiving water, the incoming pollution source is called effluent.
Infrared Spectroscopy (IR) – procedure that identifies types of organic compounds based on their characteristic absorption of infrared radiation. In general IR analysis is used to quantify total hydrocarbons in a preparation, often for fuels, oils and greases.
Inhibitors – chemicals that can block or slow down activity in a human or other organism, without causing death. Certain pollutants such as lead may be classed as inhibitors.
Injection Well – a well into which fluids are forced.
Iron Bacteria – bacteria that either utilize iron as a source of energy or cause its dissolution or deposition. The former obtain energy by oxidizing ferrous iron to ferric iron, which is precipitated as ferric hydrate; the latter, without oxidizing ferrous iron, alter environmental conditions in such a way as to cause it to be dissolved or deposited. Iron bacteria grow well in a water with high iron content.; bacteria that assimilate iron and excrete its compounds in their life processes.
Klebsiella Spp. – a genus of bacteria in the family enterobacteriaceae; nonmotile, encapsulated rods arranged singly, in pairs or in chains; some species are human pathogens.
Lactic Acid Bacteria – gram-positive, non-spore forming bacteria producing lactic acid as the major or sole product of fermentation. As a group they are important in food spoilage because they cause souring and discoloration.
Lead (analysis) – the hazards of this trace element go all the way back to the Romans, who allegedly – among other weaknesses – lost their empire because of sterility induced by imbibing wine stored in leaden vessels. Cases of lost teeth, early death, etc., are documented by the hundreds, with contamination of the victims arising either from exposure to lead on the job, or by drinking lead in some form or other as a result of the water passing through lead pipes or pipes whose joints were soldered with a lead-based solder. The amount of lead as a trace element or pollutant found in a sample of a natural resource such as air or water is called the lead load. Lead loads are heaviest in industrial areas utilizing lead in some form or other during processing.
Legionella Spp. – a genus of bacteria, some species of which have caused a type of pneumonia called Legionnaires Disease.
Listeria Spp. – a psychrotroph capable of growing at temperatures as low as 2.5° C and has high as 44° C. Because dairy products have been implicated in outbreaks of listeriosis, much research has been directed toward milk and cheese products.
Media – specific environments – air, water, soil – which are the subject of regulatory concern and activities.
Microbe – microscopic organisms such as algae, animals, viruses, bacteria, fungus and protozoa, some of which cause diseases.
Microbial – of or pertaining to microbes, single-celled organisms (e.g. bacteria).
Microbiological – a branch of biology dealing especially with microscopic forms of life.
Microorganisms – an organism of microscopic or ultramicroscopic size.
Mixture Rule – any mixture of a nonhazardous solid waste and a listed hazardous waste is itself a hazardous waste (dilution is irrelevant), although such a mixture may not exhibit a hazardous waste characteristic. A mixture of a nonhazardous solid waste and a characteristic hazardous waste remains hazardous for regulatory purposes until it no longer exhibits a characteristic of the waste.
Mold – any of a group (Myxomycetes or Mycetozoa) of organisms usually held to be lower fungi but sometimes considered protozoans that exist vegetatively as mobile plasmodia and reproduce by spores.
Most Probable Number (MPN) – a method for estimating the concentration of viable organisms (usually bacteria) in a suspension. Five tubes, containing a suitable liquid growth medium, are each inoculated with a fixed volume of the suspension. Another five tubes, containing the same medium, are each inoculated with a smaller fixed volume of the suspension, and further sets of tubes are similarly inoculated with progressively smaller volumes of the suspension. Following incubation, each tube is examined for the presence or absence of growth. Growth usually occurs in those tubes inoculated with the larger volumes of suspension – since these tubes are more likely to have received at least one viable organism in the inoculum. The concentration of viable cells in the original suspension may be calculated from the pattern of positive (growth) and negative (no growth) tubes – using statistical probability tables.
Municipal Water Analysis – analytical activities involved with monitoring regulated pollutants in municipal water treatment plant influents and effluents.
National Pollutant Discharge and Elimination System (NPDES) – federal program established through the Clean Water Act which regulates discharges into surface waters. This act requires every discharge of pollutants into a navigable water body to be pre-approved under permit by the Environmental Protection Agency on an authorized state agency.
Nitrate (water analysis) – Nitrates are fertilizers that may produce serious effects in adults, including miscarriage.
Nitrite – an intermediate in the process of nitrification. 2. Nitrous oxide salts used in food preservation.
Optical Density – a logarithmic measure of the amount of incident light attenuated. Optical density (D) is related to the transmittance (Tr) and opacity (Op) as follows: D = -log(10) Tr = -log(10)(1 – Op).
Osmophilic Microorganisms – bacteria that can withstand high concentrations of salt or sugar. These organisms are generally considered to be nonpathogenic (not capable of causing illness), but can cause spoilage in products with high concentrations of sugar.
Parasites – organism that obtains nourishment from another living organism (the host). The host, which may or may not be harmed, never benefits from the parasite. Many parasites have more than one host and most cannot survive apart from their host. Parasites include bacteria (e.g., those causing TUBERCULOSIS) along with the following:
- Fleas – small, bloodsucking wingless insects of the order Siphonaptera. Adult fleas eat only blood and are external parasites of mammals and birds. They have hard bodies flattened from side to side, piercing and sucking mouth-parts, and strong legs for jumping. Certain rat fleas carry typhus and bubonic plague; other fleas transmit tape-worms to humans.
- Nematode – member of a phylum that comprises the roundworms. Nematodes live in the water or soil. Many species, such as pinworms and hookworms, are parasites of plants and animals, including humans. Some are used as biologi-cal pesticides to control insect pests.
- Tapeworm – name for parasitic flatworms in the class Cestoda, segmented worms sometimes reaching 15-20 ft. in length. Tapeworms attach themselves to the intestinal wall of the host, which may be vertebrates or arthropods. Humans become infected with tapeworms from eating infected meat or fish. Infestation may produce no symptoms or may produce abdominal distress and weight loss. Drug treatment destroys the parasite.
Pathogens – an abbreviated term for pathogenic bacteria that includes microorganisms that can cause diseases in man. Pathogens may be airborne, waterborne or transferred from man to man and from animal to man. The presence of pathogens in sewage and other kinds of water laden with liquid wastes from human sources is determined by the presence of E. Coli. The presence of E. Coli in large quantities is indicative of the possible presence of pathogens, thus making the water polluted and unfit for humans to drink or swim in.
Polychlorinated Biphenyls (PCBs) – a series of hazardous chemical compounds which have been manufactured since the 1940s for such common purposes as electrical insulation and heating/cooling equipment. Now suspected to be carcinogens, PCBs have been disposed of in the air, on land and in water; surveys have detected the presence of PCBs in every part of the country, even those remote from PCB manufacturers.
Pesticides – Collective name for a variety of insecticides, fungicides, herbicides, algicides, fumigants and rodenticides used to kill organisms.
pH – A symbol denoting the concentration of hydrogen (H) ions in solution. A measure of acidity or alkalinity in water in which pH 7 is neutral, values above 7 are alkaline and values below 7 are acid.
Pretreatment – the reduction of the amount of pollutants, the elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater to a less harmful state prior to or in lieu of discharging or otherwise introducing such pollutants into publicly owned treatment works. The reduction of alteration can be obtained by physical, chemical or biological processes, process changes or by other means.
Proteolytic Microorganisms – a microscopic organism, including bacteria, protozoans, yeast, viruses, and algae, which catalyzes the breakdown of protein.
Protozoa – A very diverse group comprising some 50,000 eukaryotic organisms that consist of one cell. The Protozoa are grouped into several phyla, the main ones being the Sarcomastigophora (flagellates, heliozoans and amoeboid-like protozoa), the Ciliophora (ciliates) and the Apicomplexa (sporozoan parasites.)
Qualitative Research – the determination of unknown constituents of a substance. For example, determining whether a sample of salt contains the element iodine is a qualitative analysis.
Quantitative Research – the determination of the quantity or concentration of a specific substance or substances in a sample. For example, measuring the weight of any iodine in a sample of salt is a quantitative analysis.
Residential Waste – waste materials generated in homes and apartments, including paper, cardboard, beverage containers, food cans, plastics, food wastes, glass, garden and yard wastes.
Residual Waste – garbage, refuse, or other waste including solid, liquid, semisolid or contained gaseous materials resulting from industrial, mining and agricultural operations and sewage from an industrial, mining or agricultural water treatment supply facility, waste water treatment facility or air pollution control facility, provided it is not hazardous.
Resource Conservation and Recovery Act (RCRA) – federal legislation enacted in 1976 that regulates the transportation, treatment and disposal of "special" and hazardous materials and wastes.
Safe Water Drinking Act (SDWA) – enacted federal legislation that regulates the management of public water supplies. This includes community and noncommunity water supplies. Homeowners’ private wells are not under the jurisdiction of SDWA. In order to provide analytical support for this program, a laboratory must be certified by the state or the Unites States Environmental Protection Agency.
Salmonella Spp. – bacteria pathogenic to man because they cause food poisoning. There are more than 1,200 strains of this bacteria; genus of infectious bacteria that was named for the American veterinarian Daniel Elmer Salmon, who first isolated it in 1885. The organism is transmitted through contaminated poultry, eggs, and certain other foods. Three species are recognized: Salmonella typhi; S. choleraesuis; and S. enteriditis, which has more than 1,400 antigenically distinct serotypes. S. typhi produces typhoid fever. S. typhimurium, a serotype of S. enteriditis, causes salmonella gastroenteritis, a type of food poisoning characterized by abdominal pain, fever, nausea and vomiting, and diarrhea. The incubation period is 8 to 48 hours, and an attack may last from three to seven days. Mild cases are usually treated with antidiarrheal remedies; more severe cases require antibiotics. Careful cleaning and thorough cooking of food prevent salmonella infections.
Sample – in quality control, a group of samples (chemical) taken from a lot or batch of samples; in monitoring, a representative specimen of air collected for the purpose of determining its pollutant content. Other sample related terms include:
- Batch sample – the collection of samples that are drawn from a batch.
- Batch sample size – the number of samples of the same category which is randomly drawn from the batch sample and which will receive emission tests.
- Check sample – a blank which has been spiked with the analyte – chemical substance whose presence and/or concentration in a sample is determined – from an independent source in order to monitor the execution of the analytical method.
- Composite sample (or mixed sample) – a series of small samples taken over a given time period and combined as one sample in order to provide a representative analysis of the average constituent levels during the sampling period.
- Composite wastewater sample – a combination of individual samples of water or wastewater taken at selected intervals and mixed in proportion to flow or time to minimize the effect of the variability of individual samples.
- Environmental Sample (or field sample) – a representative sample of any material (aqueous – containing water, nonaqueous, or multimedia – containing water, air and land) collected from any source for which determination of composition or contamination is requested or required.
- Grab Sample – a single sample which is collected at a time and place most representative of total discharge; instantaneous sampling or a sample taken at a random location and at a random time.
- Integrated Sample – a sample obtained over a period of time with (a) the collected atmosphere being retained in a single vessel; or (b) with a separated component accumulating into a single whole. Examples are dust sampling in which all the dust separated from the air is accumulated in one mass of fluid; the absorption of acid gas in an alkaline solution; and collection of air in a plastic bag or gasometer. Such a sample does not reflect variations in concentration during the period of sampling.
- Replicate Sample – a sample that has been divided into two or more portions at a step in the measurement process. Each portion is then carried through the remaining steps in the measurement process. Duplicate samples are considered to be two replicates.
- Representative Sample – a sample of a universe or whole, such as a waste pile, lagoon or ground water which can be expected to exhibit the average properties of the whole.
- Sampling (continuous sample) – a process consisting of the withdrawal or isolation of a fractional part of a whole. In air or gas analysis, the separation of a portion of an ambient atmosphere with or without the simultaneous isolation of selected components.
- Split Sample – a sample divided into two portions, one of which is sent to a different organization or laboratory and subjected to the same environmental conditions and steps in the measurement process as the one retained in-house.
- Standard Sample – the part of finished drinking water that is examined for the presence of coliform bacteria.
- Test Sample – the collection of vehicles of the same configuration which have been drawn from the population of vehicles of that configuration and which will receive exhaust emission testing.
- Test Sample Size – the number of compressors of the same configuration in a test sample.
Sample Division – the process of extracting a smaller sample from a sample so that the representative properties of the larger sample are retained. It is assumed that no change in particle size or other characteristics occurs.
Sample Holding Time – the storage time allowed between sample collection and sample analysis when the designated preservation and storage techniques are employed.
Sample Interval – the time period between successive samples for a digital signal or between successive measurements for an analog signal.
Sample Line – a stainless steel or Teflon tube to transport the sample gas to the analyzer. The sample line should be maintained at the temperature between 150° and 175° C to prevent the condensation of samples taken.
Sample Mean (or sample average) – the average of a population calculated from the sample; it is the most commonly used measure of the center of a distribution. Its value equals the sum of the values of the observations divided by the number of observations.
Sample Preparation – the process that includes drying, size reduction, division, and mixing of a laboratory sample for the purpose of obtaining an unbiased analysis sample.
Sample Reduction – the process whereby sample particle size is reduced without change in sample weight.
Sample Size – the number of units in a sample.
Sampler – a device used with or without flow measurement to obtain any adequate portion of samples such as flue gas, water or waste for analytical purposes. May be designed for taking a single sample (grab), composite sample, continuous sample or periodic sample.
Sampling Bag – the bags used for collecting air samples from the field. When the bags are brought back to the laboratory, the collected air is then released for analysis.
Sampling Station – a location where samples are tapped (taken) for analysis.
Sampling Volume – range of the amount of sample required to perform the measurement.
Sanitary Landfill – land disposal sites for nonhazardous solid wastes at which the waste is spread in layers, compacted to the smallest practical volume and cover material applied at the end of each operating day; an engineered method of disposing of solid waste on land in a manner that protects the environment, by spreading the waste in thin layers, compacting it to the smallest practical volume and covering it with soil by the end of each working day.
Sanitary Wastewater – the wastewater discharged from conveniences such as showers, toilets and sinks.
Scale – generally insoluble deposits on equipment and heat transfer surfaces which are created when the solubility of a salt is exceeded. Common scaling agents are calcium carbonate and calcium sulfate.
Semivolatile Organic Compounds – organic compounds that volatilize slowly at standard temperature (20 degrees C and 1 atm pressure).
Sewage – waste flushed from toilets into sewers, then processed in treatment plants. Sewage disposal is the responsibility of the State Water Resources Control Board; disposal of sludge or the dried end-product of the sewage treatment process is the responsibility of the State Solid Waste Management Board.
Shelf-Life Studies – that time for which, under normal conditions, a product remains wholesome. The shelf life may be limited by a product becoming unsafe or developing unacceptable sensory qualities or by commercial considerations. In order to establish the shelf life of a product it is important to determine that change which is the first to render the product unwholesome/unacceptable. Determining shelf life requires consideration of every aspect of manufacture, storage, distribution, and consumer handling. Much information is required on the conditions to which the product is likely to be exposed during its life and the effect these are likely to have on the product itself. It is particularly important to appreciate the potential variation that may occur in a product from batch to batch and the effect this may have on the shelf life.
Shigella Spp. – bacillary dysentery is caused by certain nonmotile bacteria of the genus Shigella. This form of dysentery is usually self-limiting and rarely manifests the more severe organ involvements characteristic of amoebic dysentery. Bacillary dysentery is spread by contaminated water, milk, and food. Feces from active cases and those from healthy carriers as well contain immense numbers of the disease-producing bacteria. Flies carry the bacteria on their feet or in their saliva and feces and deposit them on food; ants are also believed to spread the disease. In the treatment of bacillary dysentery, proper replacement of fluid is important. Sulfonamides, tetracycline, and streptomycin were effective in curing acute cases until drug-resistant strains emerged. Chloramphenicol is sometimes used to treat these strains. Quinolones such as norfloxacin and ciproloxacin are also effective against Shigella infection.
Slime Forming Bacteria – the common name for bacteria in the order of myxobacterales, so named for the layer of slime deposited behind the cells as they glide on a surface.
Solid Waste – virtually any discarded material from industrial, commercial, mining, agricultural, or community activities, except for nuclear waste, domestic sewage, wastes regulated as discharges under the Clean Water Act, or manures or crop residues returned to the soil at the point of generation.
Solvents – a liquid substance that is used to dissolve or dilute another substance. Varieties of solvents include:
- Methyl Alcohol (methanol) is made synthetically and is completely miscible with water and most organic liquids;
- Ethyl alcohol (ethanol) is produced by fermentation and synthetically
- Isopropyl alcohol (isopropanol) is derived mainly from petroleum; and
- Butyl alcohol (normal butanol) is used extensively in lacquer and synthetic resin compositions and also in penetrating oils.
- Athyl acetate dissolves a large variety of materials such as nitrocellulose, oils, fats, gums, and resins
- Butyl acetate is the acetic-acid ester of normal butanol and is used extensively for dissolving various cellulose esters, minerals and vegetable oils; and
- Amyl acetate (banana oil) is used mainly in lacquers
- Aromatic hydrocarbons are derived from coal-tar distillates, the most common of which are benzene, toluene, xylene, and hi-flash naphtha or coal-tar naphtha; and
- Petroleum is hydrocarbons derived from petroleum. Common petroleum solvents include benzine, mineral spirits and kerosene.
- Chlorinated Solvents
- Carbon tetrachloride is a colorless, nonflammable liquid; and
- Trichlorethylene is similar to carbon tetrachloride but is slower in evaporation rate.
- Acetone is an exceptionally active solvent for a wide variety of organic materials, gases, liquids and solids; and
- Methylethylketone (MEK) is similar to acetone.
Special Waste – special waste does not include demolition or construction debris, industrial or commercial waste which is similar to general household solid waste, certain types of coal ash, food products in labelled containers of five gallons or less. Special waste is defined as a solid waste from a nonresidential source which is:
- a sludge waste
- an industrial process waste
- a pollution control waste; or
- contaminated soils or other materials from cleanup of a release of a, b or c above
Specimen – any material derived from a test system for examination or analysis.
Staphylococcus – any of the pathogenic bacteria parasitic to humans, that belong to the genus Staphylococcus. The spherical bacterial cells (cocci) typically occur in irregular clusters. Staphylococci cause abscesses, boils, and other infections of the skin. They can also produce infection in any organ of the body (e.g., staphylococcal pneumonia in the lungs). The most common form of food poisoning is brought on by staphylococcus-contaminated food.
Staphylococcus (and Bacillus) Enterotoxins –
Stormwater – Rainwater which has run off the ground surface, roads, roofs, paved areas etc. and is usually carried away by drains.
Streptococci – Any of a group of gram-positive bacteria of the genus Streptococcus. Streptococci are spherical in shape and divide by fission, but they remain attached and so grow in bead-like chains. Some streptococci are important in fermentation; others cause any of a wide variety of diseases including some pneumonias, scarlet fever, rheumatic fever, and, in rare cases, necrotizing fascitis, a quickly spreading infection of the flesh caused by toxins released by streptococcus bacteria that have been invaded by bacteriophages (such bacteria are sometimes popularly called flesh-eating bacteria).
Sulfate Reducing Bacteria – bacteria capable of assimilating oxygen from sulfate compounds, thereby reducing them to sulfides.
Sulfur Bacteria – the bacteria that oxidize sulfur compounds, precipitating sulfur or producing noxious sulfur gases such as hydrogen sulfide. In this process they may cause damage to concrete or other structures.
Thermoduric – refers to any organism with the ability to withstand those temperatures which are lethal for most vegetative organisms; for example, some strains of Microbacterium survive 70-80° C for 15 minutes. Among dairy microbiologists, the term thermoduric is often used to refer to those organisms which are capable of surviving pasteurization.
Thermophile – any organism having an optimum growth temperature above 45° C.
Total Dissolved Solids (TDS, also known as Total Filterable Residue) – the total dissolved (filterable) solids as determined by use of the method specified in 40 CFR 136; all material that passes the standard glass river filter; now called total filterable reside. The term is used to reflect salinity.
Total Organic Carbon Analysis (TOC) – a measure of the organic contamination of a water sample. It has an empirical relationship with the biochemical and chemical oxygen demands.
Total Petroleum Hydrocarbon (TPH) Analysis – analysis performed by gas chromatograph for diesel and lighter fuels or IR Spectroscopy for diesel and heavier fuels, oils and greases.
Total Suspended Solids (TSS, also known as Total Non-filterable Residue) – the value obtained by the method specified in 40 CFR; the total amount of both suspended and dissolved materials in wastewater. This is expressed in mg/L; a measure of the suspended solids in wastewater, effluent, or water bodies, determined by tests for "total suspended nonfilterable solids."
Toxicity – the degree of being poisonous; capability of poisonous compound to produce deleterious effects in organisms such as alteration to behavioral patterns or biological productivity or death.
Toxicity Characteristic Leaching Procedure (TCLP) – a U.S. Environmental Protection Agency test developed to evaluate the potential of a component to leach from a substance; TCLP is designed to determine the mobility of both organic and inorganic contaminants present in liquid, solid and multiphasic wastes.
Treatability – the difficulty or ease with which a pollutant can by collected and stabilized.
Underground Storage Tank (UST)/Leaking Underground Storage Tank (LUST) Regulatory Program – federal program that regulates activities associated with such tanks. The analyses include:
- BTEX – an analysis performed by gas chromatograph for Benzene, Toluene, Ethylbenzene and xylene. The presence of all four of these organic compounds indicates the presence of gasoline.
- Fuel Fingerprint – gas chromatograph analysis of a fuel to identify its source by comparison with fingerprints of fuels from known sources.
- Total Petroleum Hydrocarbon (TPH) Analysis – performed by gas chromatograph for diesel and lighter fuels or IR Spectroscopy for diesel and heavier fuels, oils and greases.
UST System – an underground storage tank, connected underground piping, underground ancillary equipment, and containment system.
Vibrio Cholerae – cholera results from infection by Vibrio cholerae, a bacterium that reproduces quickly in drinking and bathing water that has been extensively contaminated with human feces.
Vibrio Spp. – gram-negative rod-shaped bacteria (family Vibrionaceae); some species in this genus cause cholera in humans and other diseases in animals.
Volatile Organic Compound (VOC) – any organic compound which participates in atmospheric photochemical reactions, except those designated by the Environmental Protection Agency as having negligible photochemical reactivity; a chemical compound with the following properties – (1) a boiling point (o C) < 100, (2) sampling method – VOST (volatile organic sampling train), (3) capture method – tenax or tenax-charcoal, and (4) analytical method – GC/MS (gas chromatographic/mass spectroscopy).
Volatile Solids (VS, also known as volatile residue) – those solids in water, wastewater, or other liquids, that are lost on ignition of the dry solids at 550° C; the sum of a volatile matter and fixed carbon of a sample as determined by allowing a dried sample to burn to ash in a heated and ventilated furnace.
Volatiles – substances (usually a liquid) that evaporate at ordinary temperatures if exposed to the air.
Wastewater – water which has been used for some purpose and would normally be treated and discarded. Wastewater usually contains significant quantities of pollutant.
Wastewater Discharge Factor – the ratio between water discharged from a production process and the mass of product of that production process. Recycle water is not included.
Yeast – any of a number of microscopic, one-celled fungi important for their ability to ferment carbohydrates in various substances. Yeasts in general are widespread in nature, occurring in the soil and on plants. Pure yeast cultures are grown in a medium of sugars, nitrogen sources, minerals and water.
Yersinia Spp. – a Gram-negative, facultatively anaerobic, rod-shaped to ovoid bacteria of the family Enterobacteriaceae; species include Y. pestis, the causative agent of bubonic plague.
MECHANICAL TESTING - Metallurgical and Nonmetallic
Abrasion – wearing away of surface materials, such as refractories in an incinerator or parts of solid waste handling equipment, by the scouring action of moving solids, liquids, or gas; the removal of surface material from any solid through the frictional action of another solid, liquid or gas, or a combination thereof.
Adhesives – a material capable of fastening two other materials together by means of surface attachment.
Adhesive Strength – adhesive or bond strength relates to the bond between an adhesive and an adherend. It is a measure of the stress required to separate a layer of material from the base to which it is bonded.
Alloy – a substance having metallic properties and being composed of two or more chemical elements of which at least one is a metal.
Amplitude – Amplitude – the maximum absolute value attained by the disturbance of a wave or by any quantity that varies periodically.
Ash Content – the solid residue including both noncombustible inorganic (e.g., metals) and unburned organic (e.g., soot) residue that remains after a material is incinerated; inorganic residue remaining after ignition of combustible substances. The analyses of ash for commonly determined major elements by prescribed methods for the oxides of silicon, aluminum, iron, titanium, phosphorous, calcium, sodium and potassium; the mineral content of a product remaining after complete combustion.
Barcol Hardness Testing – the hardness value obtained by measuring the resistance to penetration of a spring loaded indenter steel point into the surface of the test material. The instrument, called the Barcol impressor, gives a direct reading on a 0 to 100 scale; a higher number indicates greater hardness.
Base Metal – the metal present in the largest proportion in an alloy; or the metal to be brazed, cut, soldered or welded; or after welding, that part of the metals which was not melted.
Bend Capability – the ability of a sheet to bend but not crease.
Bend Test – a test for determining relative ductility of metal that is to be formed (usually sheet, strip, plate or wire) and for determining soundness and toughness of metal (after welding, for example). The specimen is usually bent over a specified diameter through a specified angle for a specified number of cycles.
Blue Brittleness – brittleness exhibited by some steels after being heated to some temperature within the range of about 400° to 700° F, particularly if the steel is worked at the elevated temperature.
Brinell Testing – a test for determining the hardness of a material by forcing a hard steel or carbide ball of specified diameter into it under a specified load. The result is expressed as the Brinell hardness number, which is the value obtained by dividing the applied load in kilograms by the surface area of the resulting impression in square millimeters.
Brittleness – the quality of a material that leads to crack reproductions without appreciable plastic deformation, which is the deformation that does or will remain permanent after removal of the load that caused it.
Carburization – absorption and diffusion of carbon into solid ferrous alloys by heating. This is a form of case hardening that produces a carbon gradient sloping inward from the surface. The surface layer can then be hardened either by quenching (rapid cooling) directly from the carburizing temperature or by cooling to room temperature, reaustenitizing and quenching.
Carburization/Decarburization – carburization is a form of case hardening that produces a carbon gradient extending inward from the surface, enabling the surface layer to be hardened either by quenching directly from carburizing temperature or by cooling to room temperature, then reaustenitizing and quenching. Decarburization is a loss of carbon from the surface layer of a carbon-containing alloy due to reaction with one or more chemical substances in a medium that contacts the surface.
Case Depth Measurement – that portion of a ferrous alloy, extending inward from the surface, whose composition has been altered so that it can be case hardened. This is typically considered to be the portion of the alloy (a) whose composition has been measurably altered from the original composition, (b) that appears dark on an etched cross section, or (c) that has a hardness, after hardening, equal to or greater than a specified value.
Charpy Impact Strength – a pendulum-type single-blow impact test in which the specimen, usually notched (Charpy V-Notch), is supported at both ends as a simple beam and broken by a falling pendulum. The energy absorbed, as determined by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.
Classical Colorimetric Analysis – by strict definition, the term is limited to the techniques for visual identification and comparison of colored solutions. By common usage among analytical chemists, it has become a generic term for all types of analysis involving colored solutions. Identification of a substance by the hue of its solution is termed qualitative analysis. Determination of its concentration in a solution by comparison of the intensity of its color to color intensity standards is termed quantitative analysis. When the human eye is used as the detector, quantitative colorimetric methods have relatively poor precision. Moreover, the precision varies with the color because of the varying response of the eye to different colors. Most visual color comparison methods utilize white light containing all wavelengths in the visible region. Filters or monochromaters are seldom used because colorimetric methods are advantageous principally for their simplicity, speed and low cost, and for their modest demands for skill and training of the operator. Color intensities of solutions are usually compared to a set of permanent color standards. These may be solutions containing the same substance of similar hue, or colored glass.
Coefficient of Linear Thermal Expansion – the change in unit of length (or volume) accompanying a unit change of temperature.
Composites – a heterogeneous (composed of unrelated or unlike elements), solid material consisting of two or more distinct components that are mechanically or metallurgically bonded together.
Composition – the elements or compounds making up a material or produced from it by analysis.
Compression Testing – the decrease in volume that results from the application of pressure. When a material is subjected to a bending, shearing, or torsional (twisting) force, bot tensile and compressive forces are simultaneously at work. When a rod is bent, for example, one side of it is stretched and subjected to a tensional force, and the other side is compressed.
Compressive Set – a permanent deformation resulting from compression stress or load.
Compressive Strength – the maximum compressive stress that a material is capable of developing, based on the original area of cross section. If a material fails in compression (being pressed from each end) by a shattering fracture, the compressive strength has a very definite value. If a material does not fail in compressions by a shattering fracture, the value obtained for compressive strength is an arbitrary value depending upon the degree of distortion that is regarded as indicating complete failure of the material.
Computerized Numerical Control (CNC) Equipment – a control system in which numerical values corresponding to desired too or control positions are generated by a computer.
Conductivity – a measure of the quantity of electricity transferred across a unit are per unit potential gradient per unit time; reciprocal or resistivity.
Corrosion Evaluation – monitoring the deterioration of a metal by chemical or electrochemical reaction with its environment.
Creep – time-dependent strain occurring under stress. The creep strain occurring at a diminishing rate is called primary creep; that occurring at a minimum and almost constant rate is secondary creep; that occurring at an accelerating rate is tertiary creep.
Crevice and Pitting – corrosion caused by the concentration or depletion of dissolved salts, metal ions, oxygen or other gases, and such in pockets remote from the principle fluid stream, with a resultant building up of differential cells that ultimately cause deep pitting.
Cryogenic (or subzero) Testing – the study of behavior of a material at temperatures below –200° C (-328° F).
Decarburization – loss of carbon from the surface layer of a carbon-containing alloy due to reaction with one or more chemical substances in a medium that contacts the surface.
Density – the mass per unit volume of a material. The term is applicable to mixtures and pure substances and to matter in the solid, liquid, gaseous or plasma state. Density of all matter depends on its temperature. Density of a mixture may depend on its composition. Density of a gas may depend on it s pressure.
Differential Scanning Calorimetry (DSC) – direct measure of the heat flow to a sample as a function of temperature. A sample of the material weighing 5 to 10 g (18 to 36 oz.) is placed on a sample pan and heated in a time- and temperature-controlled manner. The temperature usually is increased linearly at a predetermined rate. The DSC method is used to determine specific heats, glass transition temperatures, melting points and melting profiles, percent crystallinity, degree of cure, purity, thermal properties of heat-seal packaging and hot-melt adhesives, effectiveness of plasticizers, effects of additives and fillers, and thermal history.
Deutsche Industrie Norm (DIN) – The standards set by the International Standards Organization (ISO) are used throughout the world, although some European manufacturers still use the German Industrial Standard, or Deutsche Industrie Norm (DIN). The ISO system evolved by combining the DIN system with the ASA (the industry standard previously used in the United States). The first number of an ISO rating, equivalent to an ASA rating, represents an arithmetic measure of film speed, whereas the second number, equivalent to a DIN rating, represents a logarithmic measure.
Displacement – weight of fluid, estimated or actual, that is pushed aside by a body immersed or floating in the fluid.
Drop Weight – impact resistance tests where weights are dropped on the specimen from varying heights.
Ductility – the ability of a material to deform plastically without fracturing, measured by elongation or reduction of area in a tensile test, by height of cuppin in an Erichsen test o by other means.
Durometer – an instrument for measuring hardness, that is, the resistance to the penetration (without puncturing) of the indentor into the surface of a material. The higher the number, the greater the indentation hardness.
Electrical Conductivity – the ratio of the electric current density to the electric field in a material.
Elongation – in tensile testing, the increase in the gage length (the original length of that portion of the specimen over which strain, change of length and other characteristics are measured), measured after fracture of the specimen within the gage length, usually expressed as a percentage of the original gage length.
Embrittlement – reduction in the normal ductility of a metal due to a physical or chemical change. Examples include blue brittleness, hydrogen embrittlement and temper brittleness.
Energy Dispersive Spectroscopy (EDS) – an analytical technique used for the elemental analysis or chemical characterization of a sample. It is one of the variants of XRF. As a type of spectroscopy, it relies on the investigation of a sample through interactions between electromagnetic radiation and matter, analyzing x-rays emitted by the matter in response to being hit with charged particles. Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing x-rays that are characteristic of an element's atomic structure to be identified uniquely from each other.
Extraction – the separation of specific constituents from a matrix of solids or a solution, employing mechanical and/or chemical methods; in waste treatment, extraction is to extract hazardous constituents from contaminated soil, thus circumventing the need to incinerate or otherwise treat the soil itself. In principal, extraction can be done by physical or chemical means.
Failure Analysis – determining why a part in service (a) has become completely inoperable, (b) is still operable but is incapable of satisfactorily performing its intended function; (c) has deteriorated seriously, to the point that it has become unreliable or unsafe for continued us.
Fatigue – the phenomenon leading to fracture under repeated or fluctuating stresses having a maximum value less than the tensile strength (the maximum conventional stress that a material can withstand) of the material. Fatigue fractures are progressive, beginning as minute cracks that grow under the action of the fluctuating stress. The fatigue life of a material is the number of cycles of stress that can be sustained prior to failure under a stated test condition. The fatigue limit is the maximum stress that presumably leads to fatigue fracture in a specified number of stress cycles.
Ferrite – a solid solution of one or more elements in body-centered cubic iron. Unless otherwise designated, the solute is generally assumed to be carbon.
Ferrite Content – an arbitrary, standardized value designating the amount of ferritein a stainless steel weld metal.
Ferrous Materials – those metals that are derived from iron. Iron and steel are ferrous metals.
Fillers – materials used to increase the bulk of a product without adding to its effectiveness in functional performance.
Flammability – those characteristics of a material that pertain to its relative ease of ignition and relative ability to sustain combustion. There are different industry standards and specifications to meet the many different and diversified fire conditions. Ignition tests determine the ease with which a material ignites. Burning tests determine the burning rate and the ability to self-extinguish on removal of the ignition source. The oxygen index test accurately determines relative flammability.
Flexural Properties – like tensile testing, flexural stress-strain testing determines the load necessary to generate a given level of strain on a specimen, typically using a three-point loading. The sample is characteristically 0.125 x 0.5 x 5 in. The bar is supported across a 2-inch span with a load applied at its center. Testing is performed at a constant rate of crosshead movement, typically 0.05 in./minute. Simple beam equations are used to determine the stresses on specimens at different levels of crosshead displacement. Using those equations, the flexural strength and flexural modulus of elasticity can be determined.
Flexural Strength – a measure of the ability of a material to withstand rupture when subjected to bend loading.
Fractography – descriptive treatment of fracture, especially in metals, with specific reference to photographs of the fracture surface. Macrofractography involves photographs at low magnification; microfractography involves photographs at high magnification.
Gasket – a rubber, metal or other material used to place around a joint to make the joint gas or liquid tight.
Gel Time – the period of time from the initial mixing of reactants of a liquid material composition to the point in time when gelation occurs, as defined by a specific test method.
Glass Transition Temperature – the point below which plastic behaves as glass does – it is very strong and rigid, but brittle. Above this temperature it is neither as strong or rigid as glass, but neither is it brittle. At the glass transition temperature, the plastic’s volume or length increases.
Grain Flow – fiber-like lines appearing on polished an etched sections of forgings, where are caused by orientations of the constituents of the metal in the direction of working during forging. Grain flow produced by proper die design can improve required mechanical properties of forgings.
Grain Size – in metals, a measure of the areas or volumes of grains in a polycrystalline (solid composed of many crystals) material, usually expressed as an average when the individual sizes are fairly uniform. Grain size is reported in terms of the number of grains per unit area or volume, in terms of average diameter, or as a grain-size number derived from area measurements.
Gravimetric Analysis – a variation of differential thermal analysis in which additional information is obtained by determining the rate of change in weight during the heating process.
Hardness – resistance of metal to plastic deformation, usually by indentation. However, the term may also refer to stiffness or temper, or to resistance to scratching, abrasion or cutting.
Heat-Affected Zone – that portion of the base metal that was not melted during brazing (a group of welding processes that join solid materials together by heating them to a suitable temperature and using a filler metal having a liquidus above 840° F and below the solidus of the base materials, cutting or welding, but whose microstructure and mechanical properties were altered by the heat.
Heat Transfer Analysis – the movement of heat from one body to another (gas, liquid, solid, or combinations thereof) by means of radiation, convection or conduction.
Heat Treatment – heating and cooling a solid metal or alloy in such a way as to obtain desired conditions or properties. Heating for the sole purpose of hot working is excluded from the meaning of this definition.
Humidity Testing – a corrosion test involving exposure of specimens at controlled levels of humidity and temperature.
HVAC Design – related processes designed to regulate ambient conditions within buildings for comfort or for industrial purposes. Heating an area raises temperature in a given space to a more satisfactory level than that of the atmosphere. Ventilation, either separately or in combination with the heating or air-conditioning system, controls both the supply and exhaust of air within given areas to provide sufficient oxygen to the occupants and to eliminate odors. Air Conditioning designates control of the indoor environment year-round to create and maintain desirable temperature, humidity, air circulation, and purity for the occupants of that space or for the industrial materials that are handled or stored there.
Hydrogen Embrittlement – a condition of low ductility in metals resulting from the absorption of hydrogen.
Impact Strength – the amount of energy required to fracture a material, usually measured by means of an Izod test or Charpy test. The type of specimen and test conditions affect the values and, therefore, should be specified.
Impact Test – a test to determine the behavior of materials when subjected to high rates of loading, usually in bending, tension or torsion. The quantity measured is the energy absorbed in breaking the specimen by a single blow, as in Charpy and Izod tests.
Inclusions – particles of a foreign material in a metallic matrix. The particles are usually compounds (such as oxides, sulfides or silicates), but may be of any substance that is foreign to (and essentially insoluble in) the matrix.
Inductively Coupled Plasma (ICP) Discharge – a high-temperatue (8000° - 10,000° K) discharge generated by inducing a magnetic field in a flowing conducting gas, usually argon or argon and nitrogen, by means of a water-cooled copper coil which surrounds tubes through which the gas flows.
Infrared Spectroscopy (IR) – a means of recording spectral absorptions in the infrared region using pyrolysis, transmission, and surface-reflectance techniques, exposing the sample to light in the infrared range and recording the absorption pattern yield in a "fingerprint" of the material.
Intergranular Corrosion – corrosion occurring preferentially at grain boundaries, usually with slight or negligible attack on the adjacent grains. This type of attack results from local differences in composition, such as coring commonly encountered in alloy castings.
IZOD Test – a pendulum-type single-blow impact test in which the specimen, usually notched, is fixed at one end and broken by a falling pendulum. The energy absorbed, as measured by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.
Jominy Hardenability Testing – a laboratory procedure for determining the hardenability of a steel or other ferrous alloy. Hardenability is determined by heating a standard specimen above the upper critical temperature, placing the hot specimen in a fixture so that a stream of cold water impinges on one end, and, after cooling to room temperature is completed, measuring the hardness of the surface of the specimen at regularly spaced intervals along it length. The data are normally plotted as hardness versus distance from the quenched end.
Karl Fischer Water Content – a method of determining trace quantities of water by titration; the Karl Fischer reagant is added in small increments to a glass flask containing the sample until the color changes from yellow to brown or a change in potential is observed at the end point.
Knoop Hardness – microhardness determined from the resistance of metal to indentation by a pyramidal diamond indenter, having edge angles of 172 degrees, 30’ and 130 degrees, making a rhombohedral impression with one long and one short diagonal.
Laminates – composite metals, usually in the form of a sheet or bar, composed of two or more metal layers so bonded that the composite metal forms a structural member.
Lap – a surface defect, appearing as a seam, caused by folding over hot metal, fins, or sharp corners and then rolling or forging them into the surface, but not welding them.
Load – the force in weight units applied to a body; the term load means mass or force depending on it use. A load that produces a vertically downward force because of the influence of gravity acting on a mass may be expressed in mass units. Any other load is expressed in force units.
Lubricants – any substance used to reduce friction between two surfaces in contact.
Machining – removing material from a metal part, usually using a cutting tool, and usually using a power-driven machine.
Magnetic Permeability – a factor, characteristic of a material that is proportional to the magnetic induction produced in a material divided by the magnetic field strength.
Material Defects – a departure of any quality characteristic from its intended (usually specified) level that is severe enough to cause the product or service not to fulfill its anticipated function. According to ANSI standards, defects are classified according to severity:
- Very Serious – defects which led directly to severe injury or catastrophic economic loss.
- Serious – defects which lead directly to significant injury or significant economic loss.
- Major – defects which are related to major problems with respect to anticipated use.
- Minor – defects which are related to minor problems with respect to anticipated use.
Mechanical Testing – the properties of a material that reveal its elastic and inelastic behavior when force is applied, thereby indicating its suitability for mechanical applications; different properties include modulus of elasticity, tensile strength, elongation, hardness, and fatigue limit.
Melt Flow Index – a measurement of the isothermal resistance to flow using an apparatus and test method that are standard throughout the world. It is the most widely used rheological device for examining and studying plastics in many different fabricating processes. The plastic is contained in a barrel equipped with a thermometer and surrounded by an electrical heater and an insulating jacket. A weight drives a plunger that forces the melt through a die opening. The standard procedure involves the determination of the amount of plastic extruded in 10 minutes.
Melt Flow Rate – an alternate name for the melt flow index.
Melting Point – the temperature at which a pure metal or compound from solid to liquid; the temperature at which the liquid and the solid are in equilibrium.
Metallography – the science dealing with the constitution and structure of metals and alloys as revealed by the unaided eye or by such tools as low-powered magnification, optical microscopy, electron microscopy and diffraction or x-ray techniques.
Metallurgy – the science and technology of metals and alloys. Process metallurgy is concerned with the extraction of metals from their ores and with refining of metals; physical metallurgy deals with the physical and mechanical properties of metals as affected by composition, processing and environmental conditions; and mechanical metallurgy focuses on the response of metals to applied forces.
Microanalysis – refers to carrying out various chemical operations (weighting, purification, quantitative and qualitative analysis) on samples ranging from 0.1 to 10 milligrams; this often involves use of a microscope, and still more often of chromatography; identification and chemical analysis of material on a small scale so that specialized instruments such as the microscope are needed; the material analyzed may be on the scale of 1 microgram.
Microhardness Testing – the hardness of a material as determined by forcing an indenter such as a Vickers or Knoop indenter into the surface of the material under very light load; usually the indentations are so small that they must be measured with a microscope
Microscopic – visible only at magnifications greater than 10 diameters.
Microstructure – the structure of a metal as revealed by microscopic examination of the etched surface of a polished specimen.
Military Standards (MIL-STD) – those specifications established by the governments for procedure, compatibility, and manufacture which may or may not be the same as industry. These guidelines are extremely important for government contracts and supply. They help clarify, guide and control processes and activities crucial to our everyday functioning and lives. In particular, they specify definitions, performance, and design criteria.
Modulus of Elasticity – a measure of the rigidity of metal. Technically it is the ratio of stress, below the proportional limit, to corresponding strain.
- the modulus obtained in tension or compression is Young’s modulus, stretch modulus or modulus of extensibility
- the modulus obtained in torsion or shear is the modulus of rigidity, shear modulus or modulus of torsion
- the modulus covering the ratio of the mean normal stress to the change in volume per unit volume is the bulk modulus.
Molding – the making of a form made of sand, metal or other material that contains the cavity into which molten metal is poured to produce a casting of definite shape and outline.
Non-Destructive Testing – testing to detect internal and concealed defects in materials using techniques that do not damage or destroy the items being tested; x-rays, isotropic radiation and ultrasonics are frequently used.
Nonferrous Materials – any pure metal other than iron or any metal alloy for which a metal other than iron is its major constituent in percent by weight; metals that contain no iron, e.g. aluminum, copper, brass and bronze.
Normalize (Heat Treatment Testing) – heating a ferrous alloy to a suitable temperature above the transformation range and then cooling in air to a temperature substantially below the transformation range.
O-Rings – a product of precise dimensions molded in one piece to the configuration of a torus with a circular cross section, suitable for use in a machined groove for static or dynamic service.
Oil Immersion – property of a transformer, reactor, regulator or similar apparatus whose coils are immersed in an insulating liquid that is usually, but not necessarily, oil.
Peeling – the detaching of one layer of a coating from another, or from the basis metal, because of poor adherence.
Physical Properties – properties of a metal or alloy that are relatively insensitive to structure and can be measured without the application of force; for example:
- electrical conductivity,
- coefficient of thermal expansion,
- magnetic permeability
- lattice parameter
Plasma Coatings – a thermal spraying process in which the coating material is melted with heat from a plasma torch that generates a nontransferred arc; molten coating material is propelled against the basis metal by the hot, ionized gas issuing from the torch.
Plastic – nonmetallic compounds that result from a chemical reaction and are molded or formed into rigid or pliable construction materials or fabrics.
Plasticizer Content – a material, generally an organic liquid, incorporated in a plastic or rubber formulation to soften the resin polymer and improve flexibility, ductility and extensibility; a high boiling liquid which is used in the formulation of a propellant to help make it plastic.
Plating – forming a thin, adherent layer of metal on an object. Also known as metal plating.
Polymers – a compound, normally of high molecular weight, formed by the linking of simpler molecules or monomers. A substance in which the original molecules have been linked together to form giant molecules. For example, natural rubber is a polymer of isoprene.
Porosity – fine holes or spores within a metal.
Power Factor – the ratio of the average or active power to the apparent power (root-mean-square voltage times rms current) of an alternating-current circuit. Abbreviated pf. Also known as phase factor.
Process Piping – in an industrial facility, pipework whose function is to convey the materials used for the manufacturing process.
Quantitative Metallography – determination of specific characteristics of a microstructure by making quantitative measurements on micrographs or metallographic images. Quantities o measured include volume concentration of phases, grains size, particle size, mean free path between like particles or secondary phases, and surface area to volume ratios of microconstituents, particles or grains.
Quality Characteristic – any dimension, mechanical property, physical property, functional characteristic or appearance characteristic that can be used as a basis for measuring the quality of a unit of product or service.
Research and Development (R & D) – theoretical analysis, exploration or experimentation; the extension of investigative findings and theories of a scientific or technical nature into practical application for experimental and demonstration purposes, including the experimental production and testing of models, devices, equipment, materials and processes.
Reduction of Area – in tensile testing, the percentage of decrease in cross-sectional area of a specimen at the point of rupture.
Refractive Index – the ratio of the speed of electromagnetic radiation in a vacuum space to that in a specified medium.
Refractory Materials – a material of very high melting point with properties that make it suitable for such uses as furnace linings and kiln construction.
Reinforcement – strengthening concrete, plaster or mortar by embedding steel rods or wire mesh in it; a strong inert material bonded to a plastic to enhance its strength, stiffness and resistance to impact.
Rockwell Hardness Testing – an indentation hardness test based on the depth of penetration of a specified penetrator into the specimen under certain arbitrarily fixed conditions; a value derived from the increase in depth of an impression as the load on an indenter is increased from a fixed minimum value to a higher value and then returned to the minimum value. Indentors for the test include steel balls of several specific diameters and a diamond cone penetrator having an included angle of 120° with a spherical tip have a radius of 0.2 mm (0.0070 in.) Rockwell hardness numbers are always quoted with a prefix representing the Rockwell Scale corresponding to a given combination of load and indenter.
Rockwell Superficial Testing – same as the Rockwell Hardness Test except that smaller minor and major loads are used.
Salt Spray Fog – an accelerated corrosion test in which specimens are exposed to a fine mist of a solution usually containing sodium chloride but sometimes modified with other chemicals.
Scanning Electron Microscope (SEM) – an electron microscope in which the image is formed by a beam operating in synchronism with an electron probe scanning the object. The intensity of the image forming beam is proportional to the scattering or secondary emission of the specimen where the probe strikes it.
Sealant – a viscous chemical used to seal the exposed edges of scrim reinforced geomembranes.
Seal – a continuous joint of two or more surfaces of sheet material such as made by fusion or adhesion.
Shear Strength – the stress required to produce fracture in the plane of cross section, the conditions of loading being such that the directions of force and resistance are parallel and opposite although their paths are offset a specified minimum amount.
Shore (hardness testing) – a hardness test in which the loss in kinetic energy of a falling metal "tup" absorbed by indentation upon impact of the tup on the metal being tested, is indicated by the height of rebound.
Solvents – the component of either a liquid or solid solution that is present to a greater or major extent; the component that dissolves the solute – the component of a liquid or solid solution that is present to a lesser or minor extent.
Specific Gravity – the density ratio of two substances – that of the substance of interest to that of a reference substance. The reference substance is normally water at 32° F.
Stain Resistance – the ability of a material to resist staining caused by many different factors.
Stamping – a general term covering almost all press operations. In includes:
- bending –
- blanking – a piece of sheet material produced in cutting dies that is usually subjected to further press operations, or a piece of stock from which a forging is made, often called a slug or multiple;
- coining – a closed-die squeezing operation, usually performed cold, in which all surfaces of the work are confined or restrained, resulting in a well-defined imprint of the die upon the work;
- drawing –reducing the cross section of bar stock, wire or tubing by pulling through a die;
- hot or cold forming – deforming metal at such a temperature and strain rate that recrystallization takes place simultaneously with the deformation, thus avoiding any strain hardening;
- shearing – the type of cutting action produced by rake so that the direction of chip flow is other than at right angles to the cutting edge.
Strain – a loss in ductility accompanied by an increase in hardness and strength that occurs when low-carbon steel (especially rimmed or capped steel) is aged following plastic deformation.
Stress Corrosion Cracking – failure by cracking under combined action of corrosion and stress, either external (applied) stress or internal (residual) stress. Cracking may be either intergranular or transgranular, depending on metal and corrosive medium.
Stress Relief – heating to a suitable temperature, holding long enough to reduce residual stresses and then cooling slowly enough to minimize the development of new residual stresses.
Stress Rupture Test – a method of evaluating elevated-temperature durability in which a tension-test specimen is stressed under constant load until it breaks. Data recorded commonly include initial stress, time to rupture, initial extension, creep extension and reduction of area at fracture. This is also known as a creep-rupture test.
Subzero (or cryogenic) Testing – the study of behavior of a material at temperatures below -200° C (-328° F).
Surface Chemistry – the observation and measurement of forces acting at the surfaces of gases, liquids, and solids or at the interfaces between them. This includes the surface tension of liquids (vapor pressure, solubility); emulsions (liquid/liquid interfaces); finely divided solid particles (adsorption, catalysis); permeable membranes and microporous materials; and biochemical phenomena such as osmosis, cell function and metabolic mechanisms in plants and animals. Surface chemistry has many industrial applications, a few of which are air pollution; soaps and synthetic detergents; reinforcement of rubber and plastics; behavior of catalysts; color and optical properties of paints; aerosol sprays of all types; monolayers and thin films, both metallic and organic.
Surface Finish – (1) condition of a surface as a result of a final treatment or (2) measured surface profile characteristics, the preferred term being roughness.
Tear Strength – measurement of resistance of pulp fibers to a tearing force.
Temper (Heat Treatment Testing) – to reheat hardened steel or hardened cast iron to some temperature below the eutectoid (a reversible reaction in which a solid solution is converted into two or more intimately mixed solids on cooling, the number of solids formed being the same as the components in the system) temperature for the purpose of decreasing hardness and increasing toughness.
Temper Brittleness – brittleness that results when certain steels are held within, or are cooled slowly through, a certain range of temperature below the transformation range. This brittleness is manifested as an upward shift in ductile-to-brittle transition temperature.
Tensile Bar – a molded, cast or mechanical specimen of specified cross-sectional dimensions used to determine the tensile properties of a material by use of a calibrated pull test. Also known as a tensile specimen.
Tensile Strength – the maximum conventional stress that a material can withstand.
Thermal Aging – Thermal Aging – procedure in which specimens of a selected thickness are to be oven aged at certain elevated temperatures (usually higher than the expected operating temperature, to accelerate the test), then be removed at various intervals and tested at room temperature. The properties tested can include mechanical strength, impact resistance, and electrical characteristics.
Thermal Analysis – a method for determining transformations in a metal by noting the temperatures at which thermal arrests occur. These arrests are manifested by changes in slope of the plotted or mechanically traced heating and cooling curves. When such data are secured under nearly equilibrium conditions of heating and cooling, the method is commonly used for determining certain critical temperatures required for the construction of equilibrium diagrams.
Thermogravimetric Analysis (TGA) – this method measures the weight of a substance heated at a controlled rate as a function of time or temperature. To perform the test, a sample is hung from a balance and heated in a small furnace on the TGA unit according to a predetermined temperature program. As all materials ultimately decompose on heating, and the decomposition temperature is a characteristic property of each material, TGA is an excellent technique for the characterization and quality control of materials. Properties measured include thermal decomposition temperatures, relative thermal stability, chemical composition, and the effectiveness of flame retardants. TGA also is commonly used to determine the filler content of many thermoplastics.
Thermomechanical Analysis (TMA) – TMA measures the dimensional changes as a function of temperature. The dimensional behavior of a material can be determined precisely and rapidly with small samples in any form – powder, pellet, film, fiber or molded part. The parameters measured by thermomechanical analysis are the coefficient of linear thermal expansion, the glass-transition temperature, softening characteristics, and the degree of cure. Tensile-elongation properties and the melt index can be determined by using small samples such as those cut directly from a part. Part uniformity can be determined by using samples taken from several areas of the molded part.
Titration – a method of analyzing the composition of a solution by adding known amounts of a standardized solution until a given reaction (color change, precipitation or conductivity change) is produced.
Titrimetric Analysis – quantitative analysis of solutions of known volume by unknown strength by adding reagents of known concentration until a reaction end point (color change or precipitation) is reached; the most common technique is titration.
Vickers (Microhardness Testing) – an indentation hardness test employing a 136 degree diamond pyramid indenter (Vickers) and variable loads enabling the use of one hardness scale for all ranges of hardness from very soft lead to tungsten carbide.
Water Absorption – the weight of water absorbed by a porous ceramic material, under specified conditions, expressed as a percentage of the weight of the dry material.
Water Resistance – measured ability to retard both penetration and wetting by water in liquid form; ability of part to resist deformation of change in color with immersion in water.
Waveform Analysis – the determination of the amplitude and phase of the components of a complex waveform either mathematically or by means of electronic instruments.
Weld Metal – the metal constituting the fused zone in spot, seam or projection welding.
Wet Chemistry – the determination of the quantity of a desired constituent in ores, metallurgical residues and alloys by the use of the process of solution, flotation or other liquid means.
Yield Strength – the stress at which a material exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals.
American Association of Laboratory Accreditation (A2LA) – a non-profit professional membership society for laboratory accreditation and training on laboratory practices. A2LA was organized in 1978 and first accredited laboratories in the fall of 1980. It accredits laboratories in the following fields: Acoustics & Vibration; Biological; Calibration; Chemical; Construction Materials; Electrical; Environmental; Geotechnical; Mechanical; Nondestructive and Thermal. In addition to these broad fields, specifically-tailored programs are available for animal drugs testing, asbestos, automotive EMC, calibration, environmental lead (Pb), fasteners, fertilizers, food chemistry, food microbiology, metals, and putting green materials testing. Users of laboratory services are advised to seek the specific scope of accreditation from any accredited laboratory. The scope identifies the tests, types of tests, or calibrations for which the laboratory is accredited.
American Association of State Highway and Transportation Officials (AASHTO) – the AASHTO is a nonprofit, nonpartisan association representing highway and transportation departments in the 50 states, the District of Columbia and Puerto Rico. It represents all five transportation modes: air, highways, public transportation, rail and water. Its primary goal is to foster the development, operation and maintenance of an integrated national transportation system.
American National Standards Institute (ANSI) – The American National Standards Institute (ANSI) has served in its capacity as administrator and coordinator of the United States private sector voluntary standardization system for more than 80 years. Founded in 1918 by five engineering societies and three government agencies, the Institute remains a private, nonprofit membership organization supported by a diverse constituency of private and public sector organizations. ANSI does not itself develop American National Standards (ANSs); rather it facilitates development by establishing consensus among qualified groups. The Institute ensures that its guiding principles — consensus, due process and openness — are followed by the more than 175 distinct entities currently accredited under one of the Federation’s three methods of accreditation (organization, committee or canvass). ANSI-accredited developers are committed to supporting the development of national and, in many cases international standards, addressing the critical trends of technological innovation, marketplace globalization and regulatory reform. ANSI promotes the use of U.S. standards internationally, advocates U.S. policy and technical positions in international and regional standards organizations, and encourages the adoption of international standards as national standards where these meet the needs of the user community. ANSI is the sole U.S. representative and dues-paying member of the two major non-treaty international standards organizations, the International Organization for Standardization (ISO), and, via the U.S. National Committee (USNC), the International Electrotechnical Commission (IEC).
American Petroleum Institute (API) – the oil industry’s trade association. The API, through its research and engineering work, established operating and safety standards for all segments of the petroleum industry, issues specifications for manufacturers of pipe, pressure vessels and other equipment, and furnishes statistical and other information to government agencies having to do with the industry.
American Society for Testing and Materials (ASTM) – Organized in 1898, the American Society for Testing and Materials is one of the largest voluntary standards development organizations in the world. ASTM is a not-for-profit organization that provides a forum for the development and publication of voluntary consensus standards for materials, products, systems and services. More than 32,000 members representing producers, users, ultimate consumers, and representatives of government and academia from over 100 countries develop documents that serve as a basis for manufacturing, procurement, and regulatory activities. ASTM develops standard test methods, specifications, practices, guides, classifications, and terminology in 130 areas covering subjects such as metals, paints, plastics, textiles, petroleum, construction, energy, the environment, consumer products, medical services and devices, computerized systems, electronics, and many others. ASTM Headquarters has no technical research or testing facilities; such work is done voluntarily by the ASTM members located throughout the world. More than 10,000 ASTM standards are published each year in the 73 volumes of the Annual Book of ASTM Standards. These standards and related technical information are sold throughout the world. ASTM standards are used by thousands of individuals, companies, and agencies. Purchasers and sellers incorporate standards into contracts; scientists and engineers use them in their laboratories; architects and designers use them in their plans; government agencies reference them in codes, regulations, and laws; and many others refer to them for guidance.
American Society of Mechanical Engineers (ASME) – the ASME was founded in 1880 by prominent mechanical engineers, led by Alexander Lyman Holley (1832-1882), Henry Rossiter Worthington (1817-1880), and John Edson Sweet (1832-1916). Since its inception, ASME has led in the development of technical standards, beginning with the screw thread and now numbering more than 600. The Society is best known, however, for improving the safety of equipment.
American Welding Society (AWS) – The American Welding Society (AWS) was founded in 1919 as a multifaceted, nonprofit organization with a goal to advance the science, technology and application of welding and related joining disciplines. From factory floor to high-rise construction, from military weaponry to home products, AWS continues to lead the way in supporting welding education and technology development. AWS serves 50,000 members worldwide. Membership consists of engineers, scientists, educators, researchers, welders, inspectors, welding foremen, company executives and officers, and sales associates. Interests include automatic, semi-automatic and manual welding, as well as brazing, soldering, ceramics, lamination, robotics, and welding safety and health. The AWS Certified Welding Inspector (CWI) program has been in effect for 21 years and to date, over 32,000 people have been certified to help ensure the highest quality of welding.
Gas Processors Association (GPA) – th Gas Processors Association is an organization of operating and producing companies engaged in the processing of natural gas. GPA had its beginnings in 1921 and has developed and evolved along with the gas processing industry. The active membership of GPA account for approximately 90% of all natural gas liquids produced in the United States. Since its beginning, one of the GPA’s principal contributions to the gas processing industry has been the development and promulgation of industry consensus standard specifications for natural gas liquid products. Virtually all natural gasoline sold since 1922 and all LP-Gas sold since 1930 have traded on the basis of GPA Specifications, with quality control determined by test methods originating in GPA committees. LP-Gas specifications and test methods essentially identical to GPA standards have been adopted by the American Society for Testing and Materials (ASTM), and as national standards by the American National Standards Institute (ANSI). These LP-Gas specifications and test methods served as the basis for international LP-Gas standards of the International Standards Organization (ISO). An ISO working group, monitored by GPA Staff, is responsible for the development and continued maintenance of these LP-Gas standards for international commerce.
Gas Processors Suppliers Association (GPSA) – the Gas Processors Suppliers Association (GPSA) – The Gas Processors Suppliers Association is an outgrowth of a firm request made by GPA leaders in the early days of the industry. As a result, a small group of supply companies organized the Natural Gasoline Supply Men’s Association in 1928. The name of the organization was changed in 1961 to Natural Gas Processors Suppliers Association, and in 1974 to Gas Processors Suppliers Association, to conform to that of the parent association – the GPA. Since its small beginning in 1928, GPSA has grown to an organization of about 350 companies engaged in meeting the supply and service needs of the natural gas and gas processing industry. Maintenance of the Engineering Data Book is a major function of GPSA. GPSA conducts selected research projects, carefully screened for specific application to the Engineering Data Book, and complementary to the longer-range research programs of GPA.
Indiana Department of Environmental Management (IDEM) – Indiana’s environmental regulatory agency. This is the state-level program analogous to the United State Environmental Protection Agency.
IIOA – Indiana Industrial Operators Association. The association sponsors a newsletter, in which we advertise, that is published for professionals in industrial wastewater treatment
International Organization for Standardization (ISO) – the International Organization for Standardization (ISO) is a worldwide federation of national standards bodies from some 130 countries, one from each country. ISO is a non-governmental organization established in 1947. The mission of ISO is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. ISO’s work results in international agreements which are published as International Standards.
National Aerospace and Defense Contractors Accreditation Program (Nadcap) – Nadcap represents major prime contractors, suppliers, and government agencies in aerospace, defense, and related industries throughout the United States and internationally. Nadcap is administered by the Performance Review Institute (PRI), an independent, not-for-profit trade association affiliated with the Society of Automotive Engineers (SAE). Through Nadcap, PRI accredits subcontractors and suppliers to aerospace and defense industry consensus standards.
National Association of Corrosion Engineers (NACE) – The National Association of Corrosion Engineers was established in 1943 by 11 corrosion engineers in the pipeline industry. These founding members were involved in a regional cathodic protection group formed in the 1930s, when the study of cathodic protection was introduced. With more than 50 years of experience in developing corrosion prevention and control standards, NACE International has become the largest organization in the world committed to the study of corrosion. NACE’s membership is comprised of engineers, inspectors, and technicians; presidents, business owners, and consultants; managers, supervisors, and sales representatives; scientists, chemists, and researchers; and educators and students.
National Institute of Health (NIH) – one of the world’s foremost biomedical research centers, and the federal focal point for biomedical research in the United States. The NIH mission is to uncover new knowledge that will lead to better health for everyone. NIH works toward that mission by: conducting research in its own laboratories; supporting the research of non-federal scientists in universities, medical schools, hospitals, and research institutions throughout the country and abroad; helping in the training of research investigators; and fostering communication of medical information. The NIH is one of eight health agencies of the Public Health Services which, in turn, is part of the U.S. Department of Health and Human Services. Comprised of 27 separate components, mainly Institutes and Centers, NIH has 75 buildings on more than 300 acres in Bethesda, MD.
National Institute of Standards and Technology (NIST) – established by Congress to assist industry in the development of technology, to improve product quality, to modernize manufacturing processes, to ensure product reliability, and to facilitate rapid commercialization of products based on new scientific discoveries. Now celebrating 100 years of service to the nation, the National Institute of Standards and Technology (NIST) is a non-regulatory federal agency within the Commerce Department’s Technology Administration. NIST’s mission is to promote economic growth by working with industry to develop and apply technology, measurements, and standards. NIST carries out its mission through four interwoven programs: NIST Laboratories, Baldrige National Quality Program, Manufacturing Extension Partnership, and Advanced Technology Program. NIST has an operating budget of about $720 million and operates primarily in two locations: Gaithersburg, Md. (headquarters—234 hectare/578 acre campus) and Boulder, Colo. (84 hectare/208 acre campus). NIST employs more than 3,200 scientists, engineers, technicians, business specialists, and administrative personnel. About 1,600 guest researchers complement the staff. In addition, NIST partners with 2,000 manufacturing specialists and staff at affiliated centers around the country.
Acute Testing – acute means short. In a toxicity test, it involves a stimulus severe enough to rapidly include a response. A response observed in 96 hours or less typically is considered acute. An acute effect is not always measured in terms of lethality; it can measure a variety of effect. A stimulus severe enough to rapidly induce an effect; in aquatic toxicity tests, an effect observed in 96 hours or less typically is considered acute. When referring to aquatic toxicology or human health, an acute effect is not always measured in terms of lethality.
API Gravity – gravity (weight per unit of volume) of crude oil or other liquid hydrocarbons as measured by a system recommended by the API (American Petroleum Institute). API gravity bears a relationship to true specific gravity but is more convenient to work with than the decimal fractions which would result if petroleum were expressed in specific gravity.
Aromatic CompoundsL – a group of hydrocarbon fractions that forms the basis of most organic chemicals so far synthesized. The named is derived from their "sweet, aromatic odor." The unique ring structure of their carbon atoms makes it possible to transform aromatics into an almost endless number of chemicals. Benzene, toluene and xylene are the principal aromatics and are commonly referred to as the BTX group.
Asphaltene – a product of oxidation found in some crude oil residue, in asphalt and in high temperature sludge; soluble in aromatic solvents but not soluble in naptha; components of bitumen in petroleum, petroleum products, asphalt cements and solid native bitumens.
Bioassay – the process of using the response of living organisms to determine the effect of a treatment; study of living organisms to measure the effect of a substance, factor, or condition by comparing before-and-after exposure or other data.
Biomonitoring Toxicity Tests – the use of living organisms to test the suitability of effluents for discharge into receiving waters and to test the quality of such waters downstream from the discharge; analysis of blood, urine, tissues, etc., to measure chemical exposure in humans.
Blank Samples – a sample analyzed for the purpose of determining and assessing background contaminants in the field or laboratory. There are many types of blanks for selection depending on sampling applications. For example, deionized water is one of the blanks used to rinse automatic samplers prior to the collection of samples. Other blank related terms include:
- Calibration Blank – an example is a volume of Type II water acidified with the same amounts of acids as were the standards and samples.
- Equipment Blank – opened in the field and the contents are poured appropriately over or through the sample collection device, collected in a sample container, and returned to the laboratory as a sample. These are a check on sampling device cleanliness.
- Field Blank – opened in the field and nearby the sampling platform. The purpose is to check surrounding conditions.
- Laboratory Blank – blank for evaluating contamination of laboratory measurement.
- Trip Blank – not opened in the field. The purpose is to check sample shipping conditions.
British Thermal Unit (BTU) – the amount of heat required to raise one pound of water one degree Fahrenheit.
BS&W – short for basic sediment and water often found in crude oil. Basic sediment are the impurities and foreign matter contained in a tank of crude oil, e.g., water-sand, oil-water emulsions. When produced, crude oil may contain one or more of these impurities. In the lease tank, the impurities settle to the bottom of the tank, with the relatively clean oil on top. After repeated filling and emptying of the tank, the sediment builds up to the pipeline connection and must be removed. This is done by unbolting the plate from the cleanout box on the back of the tank and shoveling out the heavy, accumulated sediment.
Calibration – the process of adjusting the instrument read out so that it corresponds to the actual concentration. It involves checking the instrument with a known concentration of a gas or vapor to see that the instrument fives the proper response. The process included:
- Initial Calibration Verification Standard – a certified or independently prepared material or mixture used to verify the accuracy of the initial calibration.
- Continuing Calibration Verification – used to assure calibration accuracy during each analysis run. It must be run for each analyte at a frequency of 10 percent of every two hours during the run, whichever is more frequent. It must also be analyzed at the beginning of the run and after the last analytical sample. Its concentration must be at or near the mid-range levels of the calibration curve.
Calibration Gas – a gas of known concentration which is used to establish the response curve of an analyzer. For total hydrocarbon measurement (THC), the concentration is expressed in terms of propane.
Certificate of Analysis – a statement of professional opinion based upon knowledge and belief.
Chromatography Analysis – a means of separating gaseous liquid, or a solid mixture, into identifiable components by passing the mixture through a solvent and then an absorbent.
Chronic Toxicity Test – a method used to determine the concentration of a substance in water that produces an adverse effect on a test organism over an extended period of time. In this test guideline, mortality and reproduction (and optionally, growth) are the criteria for toxicity.
Colorimetric Testing – an optical instrument to determine the color of oils by comparison with standard colored fluids in bottles or with standard colored discs; may be done electronically with a spectrometer.
Condensate – liquid hydrocarbons produced with natural gas which are separated from the gas by cooling and various other means. Condensate generally has an API gravity of 50° to 120° and is water-white, straw or bluish in color.
Control Sample – a material of known composition that is analyzed along with test samples in order to evaluate the accuracy of an analytical procedure.
Copper Strip Corrosion – a qualitative method of determining the corrosivity of a petroleum product by observing its effect on a strip of polished copper suspended or placed in the product; also known as copper strip test.
Drilling Fluids – fluid used to lubricate the bit and convey drill cuttings to the surface with rotary drilling equipment. Usually composed of bentonite slurry or muddy water. Can become contaminated, leading to cross contamination, and may require special disposal.
Film Strength – property of an oil enabling it to maintain an unbroken film over lubricated surfaces under operating conditions, thus avoiding the scuffing or scoring of the bearing surfaces.
Flash Point – the temperature at which the vapors rising off the surface of the heated oil will ignite with a flash of very short duration when a flame is passed over the surface. When the oil is heated to a higher temperature, it ignites and burns with a steady flame at the surface. The lowest temperature at which this will occur is knows as the burning point.
Foaming Agent – a chemical used in gas wells, oil wells producing gas, and drilling wells in which air or gas is used as the drilling fluid to lighten the water column so as to assist in the unloading of water.
Gas Chromatographs – one of the continuous emission monitors. GC is a common technique used for separating and analyzing mixtures and vapors. GC is an instrument which uses the gas chromatography separation technique to segregate the components of organic substances in a mixture. A gas mixture is percolated through a column of porous solids or liquid coated solids, which selectively retard sample components. A carrier gas is used to bring the discreet bands to a detector and through analysis of the detector response and component retention time, the sample can be identified and quantified. Gas chromatography has been in use in the laboratory since 1905, however, it has only recently been used in continuous monitoring applications.
Heavy End Component Composition – the heavier fractions of refined oil – fuel oils, lubes, paraffin and asphalt – remaining after the lighter fractions have been distilled off.
Hydrocarbons – organic compounds of hydrogen and carbon, whose densities, boiling points and freezing points increase as their molecular weights increase. There are a vast number of these compounds and they form the basis of all petroleum products. They may exist as gases, liquids or solids. An example of each is methane, hexane and asphalt.
Hydrocarbon Standards – hydrocarbons have been divided into various series, differing in chemical properties and relationships. The four that comprise most of the naturally occurring petroleums are:
- Normal Paraffin (or Alkene) Series
- Isoparaffin (or Branched-Chain Paraffins) Series
- Naphthene (or Cycloparaffin) Series
- Aromatic (or Benzene) Series
Crude oils are referred according to their relative richness in hydrocarbons of these groups as paraffinic-base, nephthenic-base or mixed base (naphthenic-paraffinic) oils. The aromatics are rarely the dominant group. The naphthenes include the complex residues of the high-boiling range (750° F) petroleum.
ISO – a prefix denoting similarity. Many organic substances, although composed of the same number of the same atoms, appear in two, three, or more varieties or isomers, which differ widely in physical and chemical properties. Turpentine and tartaric are examples.
LC 50 Testing – concentration of an active ingredient in the air which, when inhaled, kills half of the test animals exposed to it; expression of a compounds’s toxicity when present in the air as a gas, vapor, dust or mist; generally expressed in ppm (parts per million) when a gas or vapor, and in micrograms per liter when a dust or mist; often used as the measure of acute inhalation toxicity. The lower the LC50 number value, the more poisonous the pesticide.
Liquefied Natural Gas (LNG) – natural gas that has been liquefied by severe cooling (-160 degrees Celsius) for the purpose of shipment and storage in high-pressure, cryogenic tanks. To transform the liquid to a useable gas, the pressure is reduced and the liquid is warmed.
Liquefied Petroleum Gas (LPG) – hydrocarbons, gaseous at normal temperature and pressure, liquefied by pressure for storage and transport as butane and propane gases.
Paraffin – a white, odorless, tasteless and chemically inert waxy substance derived from distilling petroleum. An ultimate analysis yields on the average carbon (85 percent) and hydrogen (15 percent). It is insoluble in water, indifferent to the most powerful acids, alkalies and chlorine, and can be distilled unchanged with strong sulfuric acid. Warm alcohol, either, oil of turpentine, olive oil, benzol, chloroform, and carbon disulfide dissolve it readily.
Particle Counts – techniques by means of which bulk measurements of the grain sizes of the constituent particles of a sediment sample are made. Particles are small units of matter, often a single crystal, or part of a single crystal; they may be angular or sharp, rounded or smooth and of any shape.
pH – a symbol used in expressing both acidity and alkalinity on a scale which values range from 0 to 14, with seven representing neutrality. Numbers less than seven represent increasing acidity; greater than seven represent increasing alkalinity.
Pour Point – the temperature at which a liquid ceases to flow; or at which it congeals. This provides an indication of the presence of wax in gas oils, diesel oils, and fuel oils which might cause pumping problems.
Quality Assurance (QA) – the total integrated program for assuring the reliability of monitoring and measuring data. A system for integrating the quality planning, quality assessment and quality improvement efforts to meet user requirements; a system of activities whose purpose is to provide to the producer or user of a product or service the assurance that it meets defined standards of quality with a stated level of confidence. QA is understanding the measurement process, what needs to be measured, what needs to be done, doing what needs to be done, evaluating what was done, and reporting evaluated date which is technically sound and legally defensible.
Quality Control (QC) – the routine applications of procedures for obtaining prescribed standards of performance in the monitoring and measurement process; the overall system of activities whose purpose is to control the quality of a product or service, so that it meets the needs of users. The aim is to provide quality that is satisfactory, adequate, dependable and economic.
Reid Vapor Pressure – a measure of volatility of a fuel, its ability to vaporize. Reid Vapor Pressure, the specific designation, is named after the man who designed the test for measuring vapor pressure.
Screening Tests – determination of the relative percentages of substances, as in the suspended solids of a drilling fluid, passing through or retained on a sequence of screens of decreasing mesh size. Analysis may be by wet or dry methods.
Specific Gravity – expression of the density or weight of a unit volume of material. The specific gravity is the ratio of the weight of a unit volume of the substance in question to the weight of an equal volume of some standard substance. In the case of liquids and solids, the standard is water at a standard temperature; in some gases, the standard is hydrogen or air.
Standards – recommended practice in the manufacturing of products, materials or gases or in the conduct of a business, art or profession. They may or may not be used as or called specifications.
Traceable Standards – Traceable Standards – that a local standard has been compared and certified either directly or via not more than one intermediate standard, to a primary standard such as a National Bureau of Standards Standard Reference Material or a United States Environmental Protection Agency/National Bureau of Standards-approved Certified Reference Material.
Viscosity – one of the physical properties of a liquid, its ability to flow. The more viscous an oil, the less readily it will flow, so the term has an inverse meaning – the lower the viscosity, the faster the oil will flow. Motor oil with a viscosity of SAE 10 flows more readily than oil with a viscosity of SAE 20.