| Heterotrophic | (Environmental Engineering) A group of organisms which obtain carbon for synthesis from other organic matter or proteins. |
| Hindered (Zone) settling | (Environmental Engineering) Settling in which particle concentrations are sufficient that particles interfere with the settling of other particles. Particles settle together as a body or structure with the water required to traverse the particle interstices. |
| Hydrocarbon | (Environmental Engineering) Any organic compound composed entirely of carbon and hydrogen. Two examples are methane gas and octane. |
| Hypolimnion | (Environmental Engineering) The lower layer of a lake. |
| High-order tests - | (Software Engineering) black-box tests conducted once the software has been integrated |
| Holding Period Period | (Concrete Engineering) In the manufacture of concrete products, the period between completion of casting and the introduction of additional heat or the steam curing period |
| HRM High Reactivity Metakaolin. | (Concrete Engineering) Refined form of an ASTM C618, Class N (natural) pozzolan. A high performance, mineral admixture, similar in performance to silica fume, additionally comparable in cost. Pure white powdered in form will, not effect the natural color or darken concrete as silica fume does. Suitable for high-performance color matching in architectural concrete. Dosage at 5% to 10%, of cement by weight. No bleed water, better finishability, more creamy, cleanup is easier with slightly higher 28 day strengths and 25% - 35% less plasticizer is required than silica fume. |
| Hydrogenesis | (Concrete Engineering) Another term for condensation. The term is especially applied to base and soil substrates under highway pavements. where the barometric pump causes the inhalation of humid air, which then condenses in those structures, causing an ever increasing moisture content and sometimes instability. |
| Hydrologic Cycle | (Concrete Engineering) The Hydrologic Cycle consists of the evaporation of water from oceans and other bodies of open water; condensation to produce cloud formations; precipitation of rain, snow, sleet or hail upon land surfaces; dissipation of rain or melted solids by direct run-off into lakes and by seepage into the soil. Thereby producing a continuing endless source of water in the sub-grade. |
| habitable room | ห้องสารพัดประโยชน์ ใช้นอน รับประทานอาหาร ทำครัว ไม่รวมห้องน้ำและห้องเก็บของ |