Abrasive blasting, more known as sandblasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. A pressurised fluid compressed air, or a centrifugal wheel is used to propel the blasting material; the first abrasive blasting process was patented by Benjamin Chew Tilghman on 18 October 1870. There are several variants of the process; the most abrasive are shot sandblasting. Moderately abrasive variants include glass bead blasting and plastic media blasting with ground-up plastic stock or walnut shells and corncobs; some of these substances can cause anaphylactic shock to both passers by. A mild version is sodablasting. In addition, there are alternatives that are abrasive or nonabrasive, such as ice blasting and dry-ice blasting. Sand blasting is known as bead blasting and abrasive blasting, a generic term for the process of smoothing and cleaning a hard surface by forcing solid particles across that surface at high speeds.
Sandblasting can occur usually as a result of particles blown by wind causing aeolian erosion, or artificially, using compressed air. An artificial sandblasting process was patented by Benjamin Chew Tilghman on 18 October 1870. Sandblasting equipment consists of a chamber in which sand and air are mixed; the mixture travels through a hand-held nozzle to direct the particles toward the surface or work piece. Nozzles come in a variety of shapes and materials. Boron carbide is a popular material for nozzles. One of the original pioneers of the wet abrasive process was Norman Ashworth who found the advantages of using a wet process a strong alternative to dry blasting; the process is available in all conventional formats including hand cabinets, walk-in booths, automated production machinery and total loss portable blasting units. Advantages include the ability to use fine or coarse media with densities ranging from plastic to steel and the ability to use hot water and soap to allow simultaneous degreasing and blasting.
The reduction in dust makes it safer to use silicacious materials for blasting, or to remove hazardous material such as asbestos, radioactive or poisonous products. Process speeds are not as fast as conventional dry abrasive blasting when using the equivalent size and type of media, in part because the presence of water between the media and the substrate being processed creates a lubricating cushion that can protect both the surface and the media, reducing breakdown rates. Reduced impregnation of blasting material into the surface, dust reduction and the elimination of static cling can result in a clean surface; however wet blasting of mild steel will result in immediate or'flash' corrosion of the blasted steel substrate due to the presence of water. The lack of surface recontamination allows the use of single equipment for multiple blasting operations—e.g. Stainless steel and mild steel items can be processed in the same equipment with the same media without problems. Bead blasting is the process of removing surface deposits by applying fine glass beads at a high pressure without damaging the surface.
It is used to clean calcium deposits from pool tiles or any other surfaces, remove embedded fungus, brighten grout color. It is used in auto body work to remove paint. In removing paint for auto body work, bead blasting is preferred over sand blasting, as sand blasting tends to create a greater surface profile than bead blasting. Bead blasting is used in creating a uniform surface finish on machined parts, it is additionally used in cleaning mineral specimens, most of which have a Mohs hardness of 7 or less and would thus be damaged by sand. In wheel blasting, a spinning wheel propels the abrasive against an object, it is categorized as an airless blasting operation because there is no propellant used. A wheel machine is a high-efficiency blasting operation with recyclable abrasive. Specialized wheel blast machines propel plastic abrasive in a cryogenic chamber, is used for deflashing plastic and rubber components; the size of the wheel blast machine, the number and power of the wheels vary depending on the parts to be blasted as well as on the expected result and efficiency.
The first blast wheel was patented by Wheelabrator in 1932. Hydro blasting is not a form of abrasive blasting. Hydro-blasting known as water blasting, is used because it requires only one operator. In hydro-blasting, a pressured stream of water is used to remove old paint, chemicals, or buildup without damaging the original surface; this method is ideal for cleaning internal and external surfaces because the operator is able to send the stream of water into places that are difficult to reach using other methods. Another benefit of hydro-blasting is the ability to recapture and reuse the water, reducing waste and mitigating environmental impact. Micro-abrasive blasting is dry abrasive blasting process that uses small nozzles to deliver a fine stream of abrasive to a small part or a small area on a larger part; the area to be blasted is from about 1
Abrasion is a process of erosion which occurs when material being transported wears away at a surface over time. It is the process of friction caused by scuffing, wearing down and rubbing away of materials; the intensity of abrasion depends on the hardness, concentration and mass of the moving particles. Abrasion occurs four ways. Glaciation grinds rocks picked up by ice against rock surfaces. Solid objects transported in river channels make abrasive surface contact with walls. Objects transported in waves breaking on coastlines cause abrasion, and abrasion can be caused by wind transporting sand or small stones against surface rocks. Abrasion, under its strictest definition, is confused with attrition. Both abrasion and attrition refer to the wearing down of an object. Abrasion occurs as a result of two surfaces rubbing against each other resulting in the wearing down of one or both of the surfaces. However, attrition refers to the breaking off of particles which occurs as a result of objects hitting against each other.
Abrasion leads to surface-level destruction over time, whereas attrition results in more change at a faster rate. Today, the geomorphology community uses the term "abrasion" in a looser way interchangeably with the term "wear". Abrasion in a stream or river channel occurs when the sediment carried by a river scours the bed and banks, contributing to erosion. In addition to chemical weathering and the physical weathering of hydraulic action, freeze-thaw cycles, more, there is a suite of processes which have long been considered to contribute to bedrock channel erosion include plucking, abrasion and cavitation. Bedload transport consists of larger clasts, which cannot be picked up by the velocity of the stream flow, sliding, and/or saltating downstream along the bed. Suspended load refers to smaller particles, such as silt and finer grain sands uplifted by processes of sediment transport. Grains of various sizes and composition are transported differently in terms of the threshold flow velocities required to dislodge and deposit them, as is modeled in the Hjulström curve.
These grains scour the bedrock and banks when they make abrasive contact. Coastal abrasion occurs as breaking ocean waves containing sand and larger fragments erode the shoreline or headland; the hydraulic action of waves contributes heavily. This removes material, resulting in undercutting and possible collapse of unsupported overhanging cliffs; this erosion can threaten structure or infrastructure on coastlines, the impact will likely increase as global warming increases sea level rise. Seawalls are sometimes built in defense, but in many locations, conventional coastal engineering solutions such as sea walls are challenged and their maintenance may become unsustainable due to changes in climate conditions, sea-level rise, land subsidence, sediment supply. Abrasion platforms are shore platforms. If it is being fashioned, it will be exposed only at low tide, but there is a possibility that the wave-cut platform will be hidden sporadically by a mantle of beach shingle. If the platform is permanently exposed above the high-water mark, it is a raised beach platform, not considered a product of abrasion, but may be undercut by abrasion as sea level rises.
Glacial abrasion is the surface wear achieved by individual clasts, or rocks of various sizes, contained within ice or by subglacial sediment as the glacier slides over bedrock. Abrasion can crush smaller grains or particles and remove grains or multigrain fragments, but the removal of larger fragments is classified as plucking, the other major erosion source from glaciers. Plucking creates the debris at the base or sides of the glacier. While plucking has been thought of as a greater force of geomorphological change, there is evidence that in softer rocks with wide joint spacing that abrasion can be just as efficient. A smooth, polished surface is left behind by glacial abrasion, sometimes with glacial striations, which provide information about the mechanics of abrasion under temperate glaciers Much consideration has been given to the role of wind as an agent of geomorphological change on Earth and other planets. Aeolian processes involve wind eroding materials, such as exposed rock, moving particles through the air to contact other materials and deposit them elsewhere.
Mathematical models of these forces are notably similar to models in fluvial environments. Aeolian processes demonstrate their most notable consequences in arid regions of sparse vegetation and abundant unconsolidated sediments, such as sand. There is now evidence that bedrock canyons, landforms traditionally thought to evolve only from the fluvial forces of flowing water, may indeed be extended by the aeolian forces of wind even amplifying bedrock canyon incision rates by an order of magnitude above fluvial abrasion rates. Redistribution of materials by wind occurs at multiple geographic scales and can have important consequences for regional ecology and landscape evolution
An abrasive is a material a mineral, used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material means polishing it to gain a smooth, reflective surface, the process can involve roughening as in satin, matte or beaded finishes. In short, the ceramics which are used to cut and polish other softer materials are known as abrasives. Abrasives are commonplace and are used extensively in a wide variety of industrial and technological applications; this gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Some common uses for abrasives include grinding, buffing, cutting, sharpening and sanding. Files are not abrasives. However, diamond files are a form of coated abrasive. Abrasives rely upon a difference in hardness between the abrasive and the material being worked upon, the abrasive being the harder of the two substances. However, is not necessary as any two solid materials that rub against each other will tend to wear each other away.
Materials used as abrasives are either hard minerals or are synthetic stones, some of which may be chemically and physically identical to occurring minerals but which cannot be called minerals as they did not arise naturally. Diamond, a common abrasive, for instance occurs both and is industrially produced, as is corundum which occurs but, nowadays more manufactured from bauxite; however softer minerals like calcium carbonate are used as abrasives, such as "polishing agents" in toothpaste. These minerals are either crushed or are of a sufficiently small size to permit their use as an abrasive; these grains called grit, have rough edges terminating in points which will decrease the surface area in contact and increase the localised contact pressure. The abrasive and the material to be worked are brought into contact while in relative motion to each other. Force applied through the grains causes fragments of the worked material to break away, while smoothing the abrasive grain and/or causing the grain to work loose from the rest of the abrasive.
Some factors which will affect how a substance is abraded include: Difference in hardness between the two substances: a much harder abrasive will cut faster and deeper Grain size: larger grains will cut faster as they cut deeper Adhesion between grains, between grains and backing, between grains and matrix: determines how grains are lost from the abrasive and how soon fresh grains, if present, are exposed Contact force: more force will cause faster abrasion Loading: worn abrasive and cast off work material tends to fill spaces between abrasive grains so reducing cutting efficiency while increasing friction Use of lubricant/coolant/metalworking fluid: Can carry away swarf, transport heat, decrease friction, suspend worn work material and abrasives allowing for a finer finish, conduct stress to the workpiece. Abrasives may be classified as either synthetic; when discussing sharpening stones, natural stones have long been considered superior but advances in material technology are seeing this distinction become less distinct.
Many synthetic abrasives are identical to a natural mineral, differing only in that the synthetic mineral has been manufactured rather than mined. Impurities in the natural mineral may make it less effective; some occurring abrasives are: Calcite Emery Diamond dust Novaculite Pumice Iron oxide Sand Corundum Garnet Sandstone Tripoli Powdered feldspar StauroliteSome abrasive minerals occur but are sufficiently rare or sufficiently more difficult or costly to obtain such that a synthetic stone is used industrially. These and other artificial abrasives include: Borazon Ceramic Ceramic aluminium oxide Ceramic iron oxide Corundum Dry ice Glass powder Steel abrasive Silicon carbide Zirconia alumina Boron carbide Slags Abrasives are shaped for various purposes. Natural abrasives are sold as dressed stones in the form of a rectangular block. Both natural and synthetic abrasives are available in a wide variety of shapes coming as bonded or coated abrasives, including blocks, discs, sheets and loose grains.
A bonded abrasive is composed of an abrasive material contained within a matrix, although fine aluminium oxide abrasive may comprise sintered material. This matrix is called a binder and is a clay, a resin, a glass or a rubber; this mixture of binder and abrasive is typic
In earth science, erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, transports it to another location. This natural process is caused by the dynamic activity of erosive agents, that is, ice, air, plants and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind erosion, zoogenic erosion, anthropogenic erosion; the particulate breakdown of rock or soil into clastic sediment is referred to as physical or mechanical erosion. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Natural rates of erosion are controlled by the action of geological weathering geomorphic drivers, such as rainfall; the rates at which such processes act control. Physical erosion proceeds fastest on steeply sloping surfaces, rates may be sensitive to some climatically-controlled properties including amounts of water supplied, wind speed, wave fetch, or atmospheric temperature.
Feedbacks are possible between rates of erosion and the amount of eroded material, carried by, for example, a river or glacier. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, which control the arrival and emplacement of material at a new location. While erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the natural rate of erosion in the region. Excessive erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the eventual end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses.
Water and wind erosion are the two primary causes of land degradation. Intensive agriculture, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, the surface runoff which may result from rainfall, produces four main types of soil erosion: splash erosion, sheet erosion, rill erosion, gully erosion. Splash erosion is seen as the first and least severe stage in the soil erosion process, followed by sheet erosion rill erosion and gully erosion. In splash erosion, the impact of a falling raindrop creates a small crater in the soil, ejecting soil particles; the distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rainfall rate is greater than the rate at which water can infiltrate into the soil, surface runoff occurs.
If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope. Sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes. Where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are of the order of a few centimetres or less and along-channel slopes may be quite steep; this means that rills exhibit hydraulic physics different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when runoff water accumulates and flows in narrow channels during or after heavy rains or melting snow, removing soil to a considerable depth. Valley or stream erosion occurs with continued water flow along a linear feature; the erosion is both downward, deepening the valley, headward, extending the valley into the hillside, creating head cuts and steep banks.
In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain; the stream gradient becomes nearly flat, lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone
Deutsches Institut für Normung
Deutsches Institut für Normung e. V. is the German ISO member body. DIN is a German Registered Association headquartered in Berlin. There are around thirty thousand DIN Standards, covering nearly every field of technology. Founded in 1917 as the Normenausschuß der deutschen Industrie, the NADI was renamed Deutscher Normenausschuß in 1926 to reflect that the organization now dealt with standardization issues in many fields. In 1975 it was renamed again to Deutsches Institut für Normung, or'DIN' and is recognized by the German government as the official national-standards body, representing German interests at the international and European levels; the acronym,'DIN' is incorrectly expanded as Deutsche Industrienorm. This is due to the historic origin of the DIN as "NADI"; the NADI indeed published their standards as DI-Norm. For example, the first published standard was'DI-Norm 1' in 1918. Many people still mistakenly associate DIN with the old DI-Norm naming convention. One of the earliest, the best known, is DIN 476 — the standard that introduced the A-series paper sizes in 1922 — adopted in 1975 as International Standard ISO 216.
Common examples in modern technology include DIN and mini-DIN connectors for electronics, the DIN rail. The designation of a DIN standard shows its origin: DIN # is used for German standards with domestic significance or designed as a first step toward international status. E DIN # is a draft standard and DIN V # is a preliminary standard. DIN EN # is used for the German edition of European standards. DIN ISO # is used for the German edition of ISO standards. DIN EN ISO # is used if the standard has been adopted as a European standard. DIN 476: international paper sizes DIN 1451: typeface used by German railways and on traffic signs DIN 31635: transliteration of the Arabic language DIN 72552: electric terminal numbers in automobiles Austrian Standards Institute Swiss Association for Standardization Die Brücke, an earlier German institute aiming to set standard paper sizes DIN film speed DIN connector DQS - Deutsche Gesellschaft zur Zertifizierung von Managementsystemen, a subsidiary of DIN DGQ - Deutsche Gesellschaft für Qualität, founded DQS in 1985 together with DIN DIN home page DIN home page DIN online dictionary of classes and units of measure DQS Holding GmbH DQS HK
International Organization for Standardization
The International Organization for Standardization is an international standard-setting body composed of representatives from various national standards organizations. Founded on 23 February 1947, the organization promotes worldwide proprietary and commercial standards, it is headquartered in Geneva and works in 164 countries. It was one of the first organizations granted general consultative status with the United Nations Economic and Social Council; the International Organization for Standardization is an independent, non-governmental organization, the members of which are the standards organizations of the 164 member countries. It is the world's largest developer of voluntary international standards and facilitates world trade by providing common standards between nations. Over twenty thousand standards have been set covering everything from manufactured products and technology to food safety and healthcare. Use of the standards aids in the creation of products and services that are safe, reliable and of good quality.
The standards help businesses increase productivity while minimizing errors and waste. By enabling products from different markets to be directly compared, they facilitate companies in entering new markets and assist in the development of global trade on a fair basis; the standards serve to safeguard consumers and the end-users of products and services, ensuring that certified products conform to the minimum standards set internationally. The three official languages of the ISO are English and Russian; the name of the organization in French is Organisation internationale de normalisation, in Russian, Международная организация по стандартизации. ISO is not an acronym; the organization adopted ISO as its abbreviated name in reference to the Greek word isos, as its name in the three official languages would have different acronyms. During the founding meetings of the new organization, the Greek word explanation was not invoked, so this meaning may have been made public later. ISO gives this explanation of the name: "Because'International Organization for Standardization' would have different acronyms in different languages, our founders decided to give it the short form ISO.
ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, the short form of our name is always ISO."Both the name ISO and the ISO logo are registered trademarks, their use is restricted. The organization today known as ISO began in 1928 as the International Federation of the National Standardizing Associations, it was suspended in 1942 during World War II, but after the war ISA was approached by the formed United Nations Standards Coordinating Committee with a proposal to form a new global standards body. In October 1946, ISA and UNSCC delegates from 25 countries met in London and agreed to join forces to create the new International Organization for Standardization. ISO is a voluntary organization whose members are recognized authorities on standards, each one representing one country. Members meet annually at a General Assembly to discuss ISO's strategic objectives; the organization is coordinated by a Central Secretariat based in Geneva. A Council with a rotating membership of 20 member bodies provides guidance and governance, including setting the Central Secretariat's annual budget.
The Technical Management Board is responsible for over 250 technical committees, who develop the ISO standards. ISO has formed two joint committees with the International Electrotechnical Commission to develop standards and terminology in the areas of electrical and electronic related technologies. ISO/IEC Joint Technical Committee 1 was created in 1987 to "evelop, maintain and facilitate IT standards", where IT refers to information technology. ISO/IEC Joint Technical Committee 2 was created in 2009 for the purpose of "tandardization in the field of energy efficiency and renewable energy sources". ISO has 163 national members. ISO has three membership categories: Member bodies are national bodies considered the most representative standards body in each country; these are the only members of ISO. Correspondent members are countries; these members do not participate in standards promulgation. Subscriber members are countries with small economies, they can follow the development of standards. Participating members are called "P" members, as opposed to observing members, who are called "O" members.
ISO is funded by a combination of: Organizations that manage the specific projects or loan experts to participate in the technical work. Subscriptions from member bodies; these subscriptions are in proportion to each country's gross national trade figures. Sale of standards. ISO's main products are international standards. ISO publishes technical reports, technical specifications, publicly available specifications, technical corrigenda, guides. International standards These are designated using the format ISO nnnnn: Title, where nnnnn is the number of the standard, p is an optional part number, yyyy is the year published, Title describes the subject. IEC for International Electrotechnical Commission is included if the standard results from the work of ISO/IEC JTC1. ASTM is used for standards developed in cooperation with ASTM International. Yyyy and IS are not used for an incomplete or unpublished standard and may under some
ASTM International known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products and services. Some 12,575 ASTM voluntary consensus standards operate globally; the organization's headquarters is in West Conshohocken, about 5 mi northwest of Philadelphia. Founded in 1898 as the American Section of the International Association for Testing Materials, ASTM International predates other standards organizations such as the BSI, IEC, DIN, ANSI, AFNOR, ISO. A group of scientists and engineers, led by Charles Dudley, formed ASTM in 1898 to address the frequent rail breaks affecting the fast-growing railroad industry; the group developed a standard for the steel used to fabricate rails. Called the "American Society for Testing Materials" in 1902, it became the "American Society for Testing and Materials" in 1961 before it changed its name to “ASTM International” in 2001 and added the tagline "Standards Worldwide".
In 2014, it changed the tagline to "Helping our World Work better". Now, ASTM International has offices in Belgium, China and Washington, D. C. Membership in the organization is open to anyone with an interest in its activities. Standards are developed within committees, new committees are formed as needed, upon request of interested members. Membership in most committees is voluntary and is initiated by the member's own request, not by appointment nor by invitation. Members are classified as users, consumers, "general interest"; the latter includes consultants. Users include industry users, who may be producers in the context of other technical committees, end-users such as consumers. In order to meet the requirements of antitrust laws, producers must constitute less than 50% of every committee or subcommittee, votes are limited to one per producer company; because of these restrictions, there can be a substantial waiting-list of producers seeking organizational memberships on the more popular committees.
Members can, participate without a formal vote and their input will be considered. As of 2015, ASTM has more than 30,000 members, including over 1,150 organizational members, from more than 140 countries; the members serve on one or more of 140+ ASTM Technical Committees. ASTM International has several awards for contributions to standards authorship, including the ASTM International Award of Merit ASTM International is classified by the United States Internal Revenue Service as a 501 nonprofit organization. ASTM International has no role in enforcing compliance with its standards; the standards, may become mandatory when referenced by an external contract, corporation, or government. In the United States, ASTM standards have been adopted, by incorporation or by reference, in many federal and municipal government regulations; the National Technology Transfer and Advancement Act, passed in 1995, requires the federal government to use developed consensus standards whenever possible. The Act reflects.
Other governments have referenced ASTM standards. Corporations doing international business may choose to reference an ASTM standard. All toys sold in the United States must meet the safety requirements of ASTM F963, Standard Consumer Safety Specification for Toy Safety, as part of the Consumer Product Safety Improvement Act of 2008; the law makes the ASTM F963 standard a mandatory requirement for toys while the Consumer Product Safety Commission studies the standard's effectiveness and issues final consumer guidelines for toy safety. International Organization for Standardisation Materials property Pt/Co scale Technical standard Media related to ASTM at Wikimedia Commons ASTM International