| Agglomerating Processes | (english) "Fine particles of limestone (flux) and iron ore are difficult to handle and transport because of dusting and decomposition, so the powdery material usually is processed into larger pieces. The raw material's properties determine the technique that is used by mills. 1) SINTER Baked particles that stick together in roughly one-inch chunks. Normally used for iron ore dust collected from the blast furnaces. 2) PELLETS Iron ore or limestone particles are rolled into little balls in a balling drum and hardened by heat. 3) BRIQUETTES Small lumps are formed by pressing material together. Hot Iron Briquetting (HBI) is a concentrated iron ore substitute for scrap for use in electric furnaces. |
| Aging 1 | (english) A change in the properties of certain metal and alloys (such as steel) that occurs at ambient or moderately elevated temperatures after a hot working heat treatment or cold working operation. Typical properties impacted are hardness, yield strength, tensile strength, ductility, impact value, formability, magnetic properties, etc. See also Non-aging. |
| Aging 2 | (english) A change in properties that occurs at ambient or moderately elevated temperatures after hot working or a heat treating operation (quench aging in ferrous alloys), or after a cold working operation (strain aging). The change in properties is often, but not always, due to a phase change (precipitation), but does not involve a change in chemical composition. In a metal or alloy, a change in properties that generally occurs slowly at room temperature and more rapidly at higher temperatures. |
| AIR BLEEDER AUTOMATIC | (english) A valve that is fit into a hydraulic pipeline to facilitate automatic release of air trapped in the pipeline. See also AIR BLEEDER, MANUAL. |
| Acceleration: | (english) A vector quantity equal to the rate that velocity changes with time. |
| Axial force: | (english) A system of internal forces whose resultant is a force acting along the longitudinal axis of a structural member or assembly. |
| Adsorption | (Environmental Engineering) A surface phenomena in which a solute (soluble material) concentrates or collects at a surface (the adsorbent). |
| Advanced wastewater treatment | (Environmental Engineering) The removal of any dissolved or suspended contaminants beyond secondary treatment, often this is the removal of the nutrients nitrogen and/or phosphorus. |
| Aerobes | (Environmental Engineering) Organisms which require molecular oxygen as an electron acceptor for energy production. See anaerobes. |
| Aerobic process | (Environmental Engineering) A process which requires molecular oxygen. |