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Relative Temperature Index
The Relative thermal index (RTI) is a characteristic parameter related to the ability of plastic materials to resist thermal degradation. The RTI is part of the longterm thermal aging program (LTTA) described in the UL 746B standard from UL. During the process of the UL 746B program, the degradation in hot air of certain properties of the material like dielectric and mechanic strength, is investigated with regards to thermal-aging. For a full study, the candidate material (B) is aged together with a reference material A (control) with already known RTI value in the same ovens. The RTI is the rounded temperature in degrees C, at which the properties of ''B'' have decreased to 50 percent of their initial value in about the same amount of time (correlation time) than it takes for ''A'' at its own RTI value. A maximum correlation time of 60.000 hours is considered acceptable for many electrical applications, however it may also become as low as 5.000 hours according to UL 746B. If ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding, molded, Extrusion, extruded, or Compression molding, pressed into a diverse range of solid forms. This adaptability, combined with a wide range of other properties such as low weight, durability, flexibility, chemical resistance, low toxicity, and low-cost production, has led to their widespread use around the world. While most plastics are produced from natural gas and petroleum, a growing minority are produced from renewable resources like polylactic acid. Between 1950 and 2017, 9.2 billion metric tons of plastic are estimated to have been made, with more than half of this amount being produced since 2004. In 2023 alone, preliminary figures indicate that over 400 million metric tons of plastic were produced worldwide. If global trends ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Degradation
Thermal decomposition, or thermolysis, is a chemical decomposition of a substance caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction. Decomposition temperature definition A simple substance (like water) may exist in equilibrium with its thermal decomposition products, effectively halting the decomposition. The equilibrium fraction of decomposed molecules increases with the temperature. Since thermal decomposition is a kinetic process, the observed temperature of its beginning in most instances will be a function of the experimental conditions and sensitivity of the experimental setup. For a rigorous depiction of the process, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UL 746B
UL or Ul may refer to: Arts and media * UL (''The Belgariad''), David Eddings' character * ''New Hampshire Union Leader'', a newspaper * Unwritten Law, a punk rock band Businesses and organizations * Cambridge University Library or University Library, a library at numerous universities * SriLankan Airlines (IATA code UL) * UL (safety organization), an American worldwide safety consulting and certification company previously known as Underwriters Laboratories * Unia Lewicy a Polish political party * Unilever (stock symbol), a multinational corporation * Upplands Lokaltrafik, a Swedish transport company Universities Canada * Université Laval, Québec * University of Lethbridge, Alberta England * University of Lincoln * University of London * University of Leicester Elsewhere * University of Leoben, Austria * University of Liberia, Monrovia * University of Limerick, Ireland * University of Lima, Perú * University of Linz, Austria * University of Lisbon, Portugal * Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UL (safety Organization)
The UL enterprise is a global private safety company headquartered in Northbrook, Illinois, composed of three organizations, UL Research Institutes, UL Standards & Engagement and UL Solutions. Established in 1894, the UL enterprise was founded as the Underwriters' Electrical Bureau (a bureau of the National Board of Fire Underwriters), and was known throughout the 20th century as Underwriters Laboratories. On January 1, 2012, Underwriters Laboratories became the parent company of a for-profit company in the U.S. named UL LLC, a limited liability company, which took over the product testing and certification business. On June 26, 2022, the companies rebranded into three distinct organizations that make up the UL enterprise. The company is one of several companies approved to perform safety testing by the U.S. federal agency Occupational Safety and Health Administration (OSHA). OSHA maintains a list of approved testing laboratories, which are known as Nationally Recognized Testi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectric
In electromagnetism, a dielectric (or dielectric medium) is an Insulator (electricity), electrical insulator that can be Polarisability, polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of Polarisation density, dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly Chemical bond, bonded molecules, those molecules not only become polarised, but also reorient so that their Symmetry axis, symmetry axes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanic Strength
A mechanic is a skilled tradesperson who uses tools to build, maintain, or repair machinery, especially engines. Formerly, the term meant any member of the handicraft trades, but by the early 20th century, it had come to mean one who works with machinery. Duties Most mechanics specialize in a particular field, such as auto body mechanics, diesel mechanics, air conditioning and refrigeration mechanics, auto mechanics, bicycle mechanics, boiler mechanics, race car mechanics, aircraft mechanics, and other areas. There are also mobile mechanics who work on heavy equipment that will come to you if there is an issue that must be resolved at the location of the machine. A mechanic is typically certified by a trade association or regional government power. Mechanics may be separated into two classes based on the type of machines they work on, heavyweight and lightweight. Heavyweight work is on larger machines or heavy equipment, such as tractors, construction equipment, and trailer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celsius
The degree Celsius is the unit of temperature on the Celsius temperature scale "Celsius temperature scale, also called centigrade temperature scale, scale based on 0 ° for the melting point of water and 100 ° for the boiling point of water at 1 atm pressure." (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the closely related Kelvin scale. The degree Celsius (symbol: °C) can refer to a specific point on the Celsius temperature scale or to a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who proposed the first version of it in 1742. The unit was called ''centigrade'' in several languages (from the Latin ''centum'', which means 100, and ''gradus'', which means steps) for many years. In 1948, the International Committee for Weights and Measures renamed it to honor Celsius and also to rem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compound (chemistry), compounds, produces unique physical property, physical properties including toughness, high rubber elasticity, elasticity, viscoelasticity, and a tendency to form Amorphous solid, amorphous and crystallization of polymers, semicrystalline structures rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulation Resistance Testing
In electrical engineering, a dielectric withstand test (also pressure test, high potential test, hipot test, or insulation test) is an electrical safety test performed on a component or product to determine the effectiveness of its insulation. The test may be between mutually insulated sections of a part, or energized parts and ground. The test is a means to qualify a device's ability to operate safely during rated electrical conditions. If the current through a device under test is less than a specified limit at the required test potential and time duration, the device meets the dielectric withstand requirement. A dielectric withstand test may be done as a factory test on new equipment, or may be done on apparatus already in service as a routine maintenance test.Paul Gill (2009), ''Electrical Power Equipment Maintenance and Testing'', Second Edition, CRC Press, 1574446568, page 459 Voltage withstand testing is done with a high-voltage source and voltage and current meters. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Impact
In mechanics, an impact is when two bodies collide. During this collision, both bodies decelerate. The deceleration causes a high force or shock, applied over a short time period. A high force, over a short duration, usually causes more damage to both bodies than a lower force applied over a proportionally longer duration. At normal speeds, during a perfectly inelastic collision, an object struck by a projectile will deform, and this deformation will absorb most or all of the force of the collision. Viewed from a conservation of energy perspective, the kinetic energy of the projectile is changed into heat and sound energy, as a result of the deformations and vibrations induced in the struck object. However, these deformations and vibrations cannot occur instantaneously. A high-velocity collision (an impact) does not provide sufficient time for these deformations and vibrations to occur. Thus, the struck material behaves as if it were more brittle than it would otherwise be, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Film
Plastic film is a thin continuous polymeric material. Thicker plastic material is often called a "sheet". These thin plastic membranes are used to separate areas or volumes, to hold items, to act as barriers, or as printable surfaces. Plastic films are used in a wide variety of applications. These include: packaging, plastic bags, labels, building construction, landscaping, electrical fabrication, photographic film, film stock for movies, video tape, etc. Materials Almost all plastics can be formed into a thin film. Some of the primary ones are: * Polyethylene – The most common plastic film is made of one of the varieties of polyethylene: low-density polyethylene, medium-density polyethylene, high-density polyethylene, or linear low-density polyethylene. * Polypropylene – Polypropylene can be made a cast film, biaxially oriented film (BOPP), or as a uniaxially oriented film. * Polyester – BoPET is a biaxially oriented polyester film. * Nylon – BOPA/BON is a Bia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Materials Testing
Materials testing is used to assess product quality, functionality, safety, reliability and toxicity of both materials and electronic devices. Some applications of materials testing include defect detection, failure analysis, material development, basic materials science research, and the verification of material properties for application trials. This is a list of organizations and companies that publish materials testing standards or offer materials testing laboratory services. International organizations These organizations create materials testing standards or conduct active research in the fields of materials analysis and reliability testing. * American Association of Textile Chemists and Colorists (AATCC) * American National Standards Institute (ANSI) * American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) * American Society of Mechanical Engineers (ASME) * ASTM International * Federal Institute for Materials Research and Testing ''(Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
