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Porous Pavement Porous pavement is a permeable pavement surface with a stone reservoir underneath. Porous pavement often appears the same as traditional asphalt or concrete but is manufactured without "fine" materials, and instead incorporates void spaces that allow for infiltration. Porous pavement poses some challenges in cold weather climates, but is not impossible to use in these areas. www.greenworks.tv /stormwater/porouspavement.htm   (439 words)

Porous Media where "k" is the permeability, "Lp" is the thickness of porous sample, "A" is the radius of the sample, "t" is the tortuosity of the pore structure, and "phi" is the porosity. The shear rate dependence of the viscosity and elasticity both in bulk and in pores was measured at a frequency of 2 Hz and at 22 °C. The bulk properties were measured in a cylindrical tube of 0.0508 cm radius and 6.0 cm length. Porous media attachments are available to explore the effects of fluid flow in complex geometries. www.vilastic.com /porous.htm   (958 words)

EPA - Post-Construction Storm Water Management in New Development & Redevelopment   (Site not responding. Last check: 2007-10-08) Porous asphalt and pervious concrete appear to be the same as traditional pavement from the surface, but are manufactured without "fine" materials, and incorporate void spaces to allow infiltration. Porous pavement may also have some application on highways, where it is currently used as a surface material to reduce hydroplaning. Porous pavement cannot be used where sand is applied to the pavement surface because the sand will clog the surface of the material. cfpub.epa.gov /npdes/stormwater/menuofbmps/post_21.cfm   (1864 words)

Porous silicon lights way for new analytical devices   (Site not responding. Last check: 2007-10-08) Porous silicon is identical to the silicon used in many technological applications today, but its surface contains tiny openings, or pores, that can absorb and emit light when exposed to ultraviolet light. Porous silicon has been known to scientists since the 1950s, when they discovered that silicon could not always be polished smooth during manufacturing. Porous silicon might also be combined with new upcoming technologies, such as micro-fluidic devices, which are designed to pack dozens or hundreds of tiny "laboratories" on a single silicon chip. news.uns.purdue.edu /html4ever/990519.Buriak.nature.html   (888 words)

Pore - Wikipedia, the free encyclopedia In these cases, the pores are known as stoma. Many organic substances are porous (containing many pores), and then can be very light. Such substances include wood, and the bones of some birds, which porous structure enable these substances to be very light, but strong. en.wikipedia.org /wiki/Porous   (274 words)

Stormwater | Porous Asphalt Although the area is naturally prone to sinkholes, far fewer sinkholes have occurred in the porous asphalt areas than in the conventional asphalt areas, which the site manager attributes to the broad and even distribution of stormwater over the large areas under the porous pavement parking bays. With fewer fines, the asphalt is porous and allows water to drain though the material through virtually imperceptible openings (to the untrained eye, porous pavement properly prepared is difficult to distinguish from conventional pavement). Finally, we have avoided the use of porous asphalt in areas where the pavement is likely to be coated or paved over because of a lack of awareness, such as individual home driveways. www.forester.net /sw_0305_porous.html   (4046 words)

Porous Pavement Research Porous pavement is a best management practice for urban stormwater that has the potential to meet the key stormwater management objectives of peak discharge control, pollutant removal and runoff volume reduction. The surface layer of porous pavement may be either monolithic (such as porous asphalt or porous concrete) or modular (clay or concrete blocks). The focus of this research is on the conjunctive use of porous and impervious pavements, with the porous pavement acting as a treatment device for impervious area runoff. www.ens.gu.edu.au /eve/research/PorousPavement/PPSite.html   (693 words)

Semiconductor member, and process for preparing same and semiconductor device formed by use of same - Patent 5750000 In porous Si layer, according to observation by transmission electron microscopy, pores with diameters of about 600 angstroms on an average are formed, and despite the fact that their density is half or lower as compared with monocrystalline silicon, monocrystallinity is maintained. Also, in the step of removing the porous semiconductor substrate by etching, the substrate may be also coated with an etching preventive material except for the porous semiconductor substrate during etching so that the non-porous semiconductor monocrystalline layer and the substrate having the insulating material surface may not be deleteriously influenced by the etchant. The porous Si layer 123 can be varied in its density to a range of 1.1 to 0.6 g/cm.sup.3 by varying the HF solution concentration within the range of 50 to 20% as compared with the density of the monocrystalline Si of 2.33 g/cm.sup.3. www.freepatentsonline.com /5750000.html   (16641 words)

Ceramics Porous ceramics manufactured and sold by Soilmoisture are engineered for an "open cell/pathway" ceramic, which means that the pores and pathways are interconnected and interlinked to provide a complete flow pathway throughout the material for migrating liquids and/or gases. The hydraulic (liquid) conductivity of a porous ceramic is a measure of the rate at which a ceramic material of known thickness may conduct liquid from one surface to an opposing surface under a known pressure. Porous ceramics are a natural for a wide variety of filtering applications using liquids and pastes. www.soilmoisture.com /ceramics.html   (2136 words)

Porous - Rushmoor BC   (Site not responding. Last check: 2007-10-08) Porous asphalt has been used as a road surfacing material since the 1950s on military and civil runways. Members therefore requested further information on porous asphalt in order to determine whether or not a request could reasonably be made to Hampshire County Council to consider the material for the northern section of the Blackwater Valley Relief Road. Porous asphalt is the topmost of a number of layers within a road structure. archive.rushmoor.gov.uk /council/HIG9750.HTM   (1289 words)

TRG Porous Silicon Project   (Site not responding. Last check: 2007-10-08) Silicon, when anodized electrochemically or chemically in an HF-containing electrolyte, is etched in a manner which produces a sponge-like porous layer of silicon with pore dimensions that range from several microns in width to only a few nanometers. Though porous silicon (poSi) had been studied since the mid-1950's, it was only during the past decade that a tremendous research activity was pursued following the observation of its remarkable room temperature luminescence. Porous silicon's fortune swelled and receded many times as conflicting reports and opposing theories passed into the literature. www.chembio.uoguelph.ca /thomas/posi_research.html   (890 words)

Porous Pavements   (Site not responding. Last check: 2007-10-08) Porous pavements cause air, water, and heat to enter different parts of the environment, where they undergo different processes of storage, treatment, and flow. Porous pavements can potentially infiltrate stormwater at the source, allow the oils from cars and trucks to biodegrade safely, improve driving safety, reduce traffic noise, reduce urban temperatures, and make the "urban forest" thrive. Porous pavements are the most radical, most controversial, and most rapidly developing practice in protecting urban watersheds and aquifers. www.gactr.uga.edu /conferences/2004/Nov/05/porous_pavements.phtml   (1616 words)

Porous Silicon - Polyaniline LED Porous silicon is the result of electrochemical anodization in hydrofluoric acid. To ensure that the deposition of the polyaniline did not adversely affect the electrical activity of the porous silicon, a series of optical measurements were performed. If the recombination were due to radiative channels in the surface of the nanocrystalline grains, we would expect coating the porous silicon with a conducting polymer to have a significant impact on the recombination mechanism. www.dur.ac.uk /d.p.halliday/pub30.html   (2465 words)

Stormwater | Stormwater Control and the TMDL Program Ideally, porous pavement should be vacuumed and washed down periodically to keep its pores free of clogs. Porous pavement is a moderate hit in Virginia, where it's been used at more than 100 sites, mostly for parking, or light- to light-/moderate-usage roads. Geoblock, a porous pavement system manufactured from recycled plastic, consists of a series of interlocking, high-strength blocks for supporting heavy or concentrated loads while also protecting turf. www.forester.net /sw_0103_porous.html   (3059 words)

POROUS PAVEMENT: Pavement That Leaks Porous pavement is an innovative technique which can lead to environmental and economic improvements in the way we pave our parking areas and roads. Porous pavement will reduce or eliminate spring potholes, which are caused by the freezing and expansion of water trapped within road cracks. Impacts of porous pavements on the local hydrology and water quality are site-specific, and should be evaluated on a case-by-case basis. www.millermicro.com /porpave.html   (2284 words)

EETimes.com - Litho process hardens porous silicon   (Site not responding. Last check: 2007-10-08) Porous silicon became a hot research topic over a decade ago, when reseachers found that a standard silicon wafer, when deeply etched with hydrofluoric acid, would take on unusual physical properties. The discovery of porous silicon's light-absorbing and -emitting properties prompted researchers to attempt to use light to internally transmit data inside chips, instead of encoding data in electron streams or depending on external gallium arsenide chips to translate electricity into light. However, porous silicon proved to be too unstable to be commercialized, since many normal environmental chemicals — such as oxygen and humidity — corrode the porous silicon, thereby nixing its light-absorption and -emitting capabilities. www.eetimes.com /story/OEG20011015S0066   (1006 words)

Porous Silicon Sensor May Offer Multiple Advantages Sensors based on porous silicon have been built before, but their practicality has been limited because of high resistance in the electrodes connected to the porous silicon and the power requirements of as much as 5 volts. Porous silicon has attracted considerable interest because it produces a strong orange-red photoluminescence when subjected to ultraviolet light. The basis for the approach lies in the suggestion that the photoluminescence from porous silicon results from a surface based process and that this relatively long-lived photoluminescence can be used to enhance the rate of reduction of metallic ions from the electroless metallization solution in contact with the porous silicon surface. unisci.com /stories/20021/0313025.htm   (922 words)

Stormwater | Advances in Porous Pavement Porous pavements, designed to allow air and water to pass through, are today just a small fraction of all pavement installations. All interstate highways in Georgia and Oregon are repaved with porous asphalt. Porous pavers, for example, have been installed in Ontario, Canada, and are doing fine. www.forester.net /sw_0503_advances.html   (3276 words)

RECEMAT International, metal foam, porous metal Recemat porous metal foam or metallic foam is nickel foam and metaalschuim has Metallschaum in mousse métallique or cellular stucture with open cell or cells and high porosity. Recemat porous metal is open cell metal foam with metallic foam, nickel foam, metaalschuim, Metallschaum, mousse métallique cellular metal with high porosity or foam nickel. Recemat open cell metal foam is porous metal, metallic foam as nickel foam and metaalschuim is Metallschaum or mousse métallique. www.recemat.com   (295 words)

Porous Silicon   (Site not responding. Last check: 2007-10-08) Multilayer porous silicon films are simply created by periodically varying the current density in time. Liquid crystals are unifomly infiltrated throughout the porous silicon microcavity to enable the active tunability. When a voltage is applied or the structure is heated, the position of the reflectance resonance shifts and the device transitions from an off-state (high reflectance) to an on-state (low reflectance). www.ece.rochester.edu /~weiss/Porous_silicon.html   (244 words)

Digital images and computer modelling - Porous materials In thinking about the micro-geometry of porous materials, a common approach is to consider them to be two-phase solid-pore composites, even though the solid phase can be heterogeneous. The topology of the pore space of a porous material is very important in determining the properties of the material, and even in properly formulating ideas about the pore space in the first place. When looking at a slice of a porous material, one must of course be aware whether the material is isotropic or not. ciks.cbt.nist.gov /garbocz/appendix3/node2.html   (777 words)

Silica Aerogels - Pore Structure   (Site not responding. Last check: 2007-10-08) The International Union of Pure and Applied Chemistry has recommended a classification for porous materials where pores of less than 2 nm in diameter are termed "micropores", those with diameters between 2 and 50 nm are termed "mesopores", and those greater than 50 nm in diameter are termed "macropores". Pores in various materials are either open or closed depending on whether the pore walls are solid or themselves porous (or at least "holey"). A macroscopic example of a open-pored material is a common sponge, while "bubble wrap" packaging is an example of a closed-pore material. eande.lbl.gov /ECS/aerogels/sapore.htm   (683 words)

UKC Porous-Media home page We have been studying porous media for a number of years, primarilly by a variety of Nuclear Magnetic Resonance and neutron scattering techniques. One may generate model porous structures and study them by analytic and numerical techniques, and then compare the predicted properties with the measured ones. Porous materials for Chemical Sensors - sol-gel materials are being developed for application as optical and semiconductor chemical sensors. www.kent.ac.uk /physical-sciences/porous-media/html/porous-media.html   (264 words)

Search Results for porous - Encyclopædia Britannica The spinodal mechanism described in Glass formation: Phase separation is at the heart of the trademarked Vycor process for obtaining a glass of 96 percent silica and 4 percent sodium borate. separation of gold or silver from impurities by melting the impure metal in a cupel (a flat, porous dish made of a refractory, or high-temperature-resistant, material) and then directing a blast of... Iron powders produced by crushing and grinding or by atomizing a stream of molten metal are made into small components by pressing or rolling them into compacts, which are then sintered. www.britannica.com /search?query=porous&submit=Find&source=MWTEXT   (381 words)

Amazon.com: The Physics of Fluids in Hierarchical Porous Media: Angstroms to Miles (Theory and Applications of ...   (Site not responding. Last check: 2007-10-08) Porous media are ubiquitous throughout nature and in many modern technologies. Because of their omnipresent nature, porous media are studied to one degree or another in almost all branches of science and engineering. This text is an outgrowth of a two-semester graduate course on multiscale porous media offered to students in applied math, physics, chemistry, engineering (civil, chemical, mechanical, agricultural), and environmental and soil science. www.amazon.com /exec/obidos/tg/detail/-/0792347420?v=glance   (501 words)

Wired News: First Steps for Bionic Woman Researchers at De Montfort University in Leicester, England, have successfully taken porous silicon and attached and grown mammal cells, an important first step in the development of tissue and silicon sensory interaction. She said these results must be duplicated to confirm the nontoxicity of porous silicon. The discovery of porous silicon was a fluke. www.wired.com /news/technology/0,1282,19005,00.html   (586 words)

Advanced Glass and Ceramics Advanced Glass and Ceramics is a premier supplier and specialty machining house for porous glass, including Corning’s Vycor® 7930 porous glass and porous Pyrex® glass. Porous Vycor® glass and other porous materials are used in applications such as: sensors; detectors; HPLC frits; gas, liquid and petroleum separation; gas adsorption; filters; vacuum chucks; reference electrodes; lasers; medical devices; optics and other applications. Porous Vacuum Chucks including Porous glass, porous ceramics and other porous materials. www.porousglass.com   (179 words)

Porous Ceramic Soil Amendment   (Site not responding. Last check: 2007-10-08) Specific objectives were (i) to determine if a porous ceramic reduces incidence, or improves recovery from localized dry spot on a high sand content golf green and (ii) to determine water retention properties of sand-porous ceramic soil amendment mixtures supporting dwarf bermudagrass growth. In this study, addition of a porous ceramic soil amendments reduced soil and surface temperatures on a sand based golf green compared to addition of 50:50 mixture of porous ceramic and sand, or spraying with a wetting agent. Results from this study indicated that under some conditions, porous ceramic may improve water status and K supply to dwarf bermudagrass grown in a sand, resulting in a higher quality turf. turf.ufl.edu /research/ceramend.htm   (547 words)

Sintered, Plastics, Filter, Cylinder   (Site not responding. Last check: 2007-10-08) Porous plastics retain most of the physical properties of their solid counterparts, but also offer a unique set of properties. Porous plastics have excellent resiliency; high physical strength and lightweight providing a rugged easily handled part. Gopani Product System’s precision molded porous plastic parts and shapes are found in a broad range of applications in the industrial, medical and consumer products markets. www.gopani.com /porous_plastics_filter_cylinders.html   (402 words)

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