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Lightweight Expanded Clay Aggregate
Lightweight expanded clay aggregate (LECA) or expanded clay (exclay) is a lightweight aggregate made by heating clay to around in a rotary kiln. The heating process causes gases trapped in the clay to expand, forming thousands of small bubbles and giving the material a porous structure. LECA has an approximately round or oblong shape due to circular movement in the kiln and is available in different sizes and densities. LECA is used to make lightweight concrete products and other uses. History LECA was developed about 1917 in Kansas City, Missouri, to the production in a rotary kiln of a patented expanded aggregate known as Haydite which was used in the construction of SS Selma, an ocean-going ship launched in 1919. Following in the USA was the development of a series of aggregates known as Gravelite, Perlite, Rocklite, etc. In Europe, LECA commenced in Denmark, Germany, Netherlands, and UK. Characteristics LECA is usually produced in different sizes and densities from up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various #Units, units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the International System of Units, SI unit of pressure, the Pascal (unit), pascal (Pa), for example, is one newton (unit), newton per square metre (N/m2); similarly, the Pound (force), pound-force per square inch (Pound per square inch, psi, symbol lbf/in2) is the traditional unit of pressure in the imperial units, imperial and United States customary units, US customary systems. Pressure ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquaponics
Aquaponics is a food production system that couples aquaculture (raising aquatic animals such as fish, crayfish, snails or prawns in tanks) with hydroponics (cultivating plants in water) whereby the nutrient-rich aquaculture water is fed to hydroponically grown plants. Plants are grown in hydroponics systems, with their roots immersed in the nutrient-rich effluent water. This enables them to filter out the ammonia that is toxic to the aquatic animals, or its metabolites. After the water has passed through the hydroponic subsystem, it is cleaned and oxygenated, and can return to the aquaculture vessels. The size, complexity, and types of foods grown in an aquaponic system can vary as much as any system found in either distinct farming discipline. The main fish grown in aquaponics are tilapia, koi, goldfish, carp, catfish, barramundi, and different types of ornamental fish. The main plants produced include lettuce, pak choi, kale, basil, mint, watercress, tomatoes, p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroponics
Hydroponics is a type of horticulture and a subset of #Passive sub-irrigation, hydroculture which involves growing plants, usually crops or medicinal plants, without soil, by using water-based mineral Plant nutrition, nutrient Solution (chemistry), solutions in an artificial environment. Terrestrial plant, Terrestrial or aquatic plants may grow freely with their roots exposed to the nutritious liquid or the roots may be mechanically supported by an inert medium such as perlite, gravel, or Hydroponics#Substrates (growing support materials), other substrates. Despite inert media, roots can cause changes of the rhizosphere pH and root exudates can affect rhizosphere biology and physiological balance of the nutrient solution when secondary metabolites are produced in plants. Genetically modified plant, Transgenic plants grown hydroponically allow the release of Pharming (genetics)#In plants, pharmaceutical proteins as part of the root exudate into the hydroponic medium. The nutri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoclaved Aerated Concrete
Autoclaved aerated concrete (AAC) also referred to as autoclaved cellular concrete (ACC) or simply autoclaved concrete is a lightweight, prefabricated concrete building material. Developed in the mid-1920s, it is an alternative to traditional concrete blocks and clay bricks. AAC products are factory-prefabricated, in contrast to cellular concrete, which is typically mixed and poured on-site. AAC is a combination of quartz sand, gypsum, lime, Portland cement, water, fly ash, and aluminium powder. After the aerated mixture is partially cured in a mould, the material is further cured under heat and pressure in an autoclave. AAC can be made into blocks, wall panels, floor and roof panels, cladding (façade) panels, and lintels. AAC materials are typically cut using standard power tools equipped with carbon steel cutters. AAC products may be used in various construction projects similarly to cellular concrete.For any exterior use, they may require an applied finish to gua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete Slab
A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner ''mud slabs'' may be used for exterior paving . In many domestic and industrial buildings, a thick concrete slab supported on foundations or directly on the subsoil, is used to construct the ground floor. These slabs are generally classified as ''ground-bearing'' or ''suspended''. A slab is ground-bearing if it rests directly on the foundation, otherwise the slab is suspended. For multi-story buildings, there are several common slab designs : * Beam and block, also referred to as ''rib and block'', is mostly used in residential and industrial applications. This slab type is made up of pre-stressed beams and hollow blocks and are temporarily propped until set, typically after 21 days. * A hollow core slab which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete Masonry Unit
A concrete block, also known as a cinder block in North American English, breeze block in British English, or concrete masonry unit (CMU), or by various other terms, is a standard-size rectangular block used in building construction. The use of blockwork allows structures to be built in the traditional masonry style with layers (or courses) of staggered blocks. Concrete blocks may be produced with hollow centers (cores) to reduce weight, improve insulation and provide an interconnected void into which concrete can be poured to solidify the entire wall after it is built. Concrete blocks are some of the most versatile building products available because of the wide variety of appearances that can be achieved using them. Naming Those that use cinders (fly ash or bottom ash) as an aggregate material are called ''cinder blocks'' in the United States. They are also known as ''breeze blocks'', a term derived from ''breeze'', referring to the small cinders and cinder-dust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filtration
Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as ''oversize'' and the fluid that passes through is called the ''filtrate''. Oversize particles may form a filter cake on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as ''blinding''. The size of the largest particles that can successfully pass through a filter is called the effective ''pore size'' of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size, filter thickness and biological activity). Filtration occurs both in nature and in engineered systems; there are biological, geological, and industrial forms. In everyday us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drainage
Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess water. The internal drainage of most agricultural soils can prevent severe waterlogging (anaerobic conditions that harm root growth), but many soils need artificial drainage to improve production or to manage water supplies. History Early history The Indus Valley Civilization had sewerage and drainage systems. All houses in the major cities of Harappa and Mohenjo-daro had access to water and drainage facilities. Waste water was directed to covered gravity sewers, which lined the major streets. 18th and 19th century The invention of hollow-pipe drainage is credited to Sir Hugh Dalrymple, who died in 1753. Current practices Simple infrastructure such as open drains, pipes, and berms are still common. In modern times, more complex structures involving substantial earthworks and new technologies have been common as well. Geotextiles New storm water drainag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (biology)
In biology, a substrate is the surface on which an organism (such as a plant, fungus, or animal) lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants. In biology substrates are often activated by the nanoscopic process of substrate presentation. In agriculture and horticulture * Cellulose substrate * Expanded clay aggregate (LECA) * Rock wool * Potting soil * Soil In animal biotechnology Requirements for animal cell and tissue culture Requirements for animal cell and tissue culture are the same as described for plant cell, tissue and organ culture (In Vitro Culture Techniques: The Biotechnological Principles). Desirable requirements are (i) air conditioning of a room, (ii) hot room with temperature recorder, (iii) microsc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word ''earthquake'' is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining, fracking, and nuclear weapons testing. The initial point of rupture is called the hypocenter or focus, while the ground level directly above it is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melting
Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point. At the melting point, the ordering of ions or molecules in the solid breaks down to a less ordered state, and the solid melts to become a liquid. Substances in the molten state generally have reduced viscosity as the temperature increases. An exception to this principle is elemental sulfur, whose viscosity increases in the range of 130 °C to 190 °C due to polymerization. Some organic compounds melt through mesophases, states of partial order between solid and liquid. First order phase transition From a thermodynamics point of view, at the melting point the change in Gibbs free energy ''∆G'' of the substances is zero, but there are non-zero changes in the entha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
