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Flowers Of Sulfur
Flowers of sulfur (British spelling flowers of sulphur) is a very fine, bright yellow sulfur powder that is produced by sublimation and deposition. It can contain up to 30% of the amorphous allotrope of sulfur, which is the noncrystalline structure of sulfur. It is known as ' by apothecaries and in older scientific works. Natural sulfur was also known as brimstone, hence the alternative name flowers of brimstone. Flowers of sulfur has unique properties. Production occurs mainly through sublimation of natural sulfur. According to The Sulphur Institute, flowers of sulphur is widely used due to its powdered structure in rubber vulcanization, agricultural dusts, pharmaceutical products, stock feeds. It can also be used in Flowers of Sulfur (FoS) Tests. Properties Although similar to chemically pure sulfur, flowers of sulfur has slightly different properties. For instance, sulfur is completely soluble in sulfur disulfide. Flowers of sulfur, however, is insoluble in sulfur dioxid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungal Disease
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''true fungi' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy-dispersive X-ray Spectroscopy
Energy-dispersive X-ray spectroscopy (EDS, EDX, EDXS or XEDS), sometimes called energy dispersive X-ray analysis (EDXA or EDAX) or energy dispersive X-ray microanalysis (EDXMA), is an analytical technique used for the elemental analysis or chemical characterization of a sample. It relies on an interaction of some source of X-ray excitation and a sample. Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing a unique set of peaks on its electromagnetic emission spectrum (which is the main principle of spectroscopy). The peak positions are predicted by the Moseley's law with accuracy much better than experimental resolution of a typical EDX instrument. To stimulate the emission of characteristic X-rays from a specimen a beam of electrons is focused into the sample being studied. At rest, an atom within the sample contains ground state (or unexcited) electrons in discrete energy levels or electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Photoelectron Spectroscopy
X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique based on the photoelectric effect that can identify the elements that exist within a material (elemental composition) or are covering its surface, as well as their chemical state, and the overall electronic structure and density of the electronic states in the material. XPS is a powerful measurement technique because it not only shows what elements are present, but also what other elements they are bonded to. The technique can be used in line profiling of the elemental composition across the surface, or in depth profiling when paired with Ion beam#Ion beam etching or sputtering, ion-beam etching. It is often applied to study chemical processes in the materials in their as-received state or after cleavage, scraping, exposure to heat, reactive gasses or solutions, ultraviolet light, or during ion implantation. XPS belongs to the family of Photoemission spectroscopy, photoemission spect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Board
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a Lamination, laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with an artwork pattern of traces, planes and other features (similar to wires on a flat surface) Chemical milling, etched from one or more sheet layers of copper Lamination, laminated onto and/or between sheet layers of a Insulator (electricity), non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds Via (electronics), vias: plated-through holes that allow interconnections between layers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conformal Coating
Conformal coating is a protective coating of thin polymeric film, applied to printed circuit boards (PCB). The coating is named conformal since it ''conforms'' to the contours of the PCB. Conformal coatings are typically applied at 25-250 μm to the electronic circuitry and provides it protection against moisture, dust, chemicals, and temperature extremities. Coatings can be applied in a number of ways, including brushing, spraying, dispensing and dip coating. Furthermore, a number of materials can be used as a conformal coating, such as acrylics, silicones, urethanes and parylene. Each has their own characteristics, making them preferred for certain environments and manufacturing scenarios. Most circuit board assembly firms coat assemblies with a layer of transparent conformal coating, which is lighter and easier to inspect than potting. Reasons for use Conformal coatings are used to protect electronic components from the environmental factors they are exposed to. Examples of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The underground mine gas term for foul-smelling hydrogen sulfide-rich gas mixtures is ''stinkdamp''. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. The British English spelling of this compound is hydrogen sulphide, a spelling no longer recommended by the Royal Society of Chemistry or the International Union of Pure and Applied Chemistry. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or it or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of copper extraction and the burning of sulfur- bearing fossil fuels. Structure and bonding SO2 is a bent molecule with ''C''2v symmetry point group. A valence bond theory approach considering just ''s'' and ''p'' orbitals would describe the bonding in terms of resonance between two resonance structures. The sulfur–oxygen bond has a bond order of 1.5. There is support for this simple approach that does not invoke ''d'' orbital participation. In terms of electron-counting formalism, the sulfur atom has an oxidation state of +4 and a formal charge of +1. Occurrence Sulfur dioxide is found on Earth and exists in very small concentrations and in the atmosphere at about 1 ppm. On other planets, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Fumarole (23998018863)
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere The greatest commercial use of the element is the production of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center For Advanced Life Cycle Engineering
The Center for Advanced Life Cycle Engineering (CALCE) is a university research facility focused on risk assessment, management, and mitigation for electronic products and systems. CALCE is the largest electronic products and systems research center focused on electronics reliability and is dedicated to providing a knowledge and resource base to support the development of competitive electronic components, products, and systems. CALCE is located at the University of Maryland in College Park, Maryland, and was founded by Professor Michael Pecht. Overview CALCE was created in 1985 with support from the United States National Science Foundation as a University Industry Cooperative Research Center. Since that time, CALCE has made significant contributions in the following areas: * Design for Reliability and Physics-based Reliability Assessment * Accelerated Test Methods * Industry Standards Development * Electronics Supply Chain Management * Reliability Analysis and Qualification ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mold (fungus)
A mold () or mould () is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not all fungi form molds. Some fungi form mushrooms; others grow as single cells and are called microfungi (for example yeasts). A large and taxonomically diverse number of fungal species form molds. The growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism. The hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls (septa) may delimit connected compartments along the hyphae, each containing one or multiple, genetically identical nuclei. The dusty texture of many molds is caused by profuse production of asexual spores ( conidia) formed by di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
