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Paste (rheology)
In physics, a paste is a substance that behaves as a solid until a sufficiently large load or stress is applied, at which point it flows like a fluid. In rheological terms, a paste is an example of a Bingham plastic fluid. Pastes typically consist of a suspension of granular material in a background fluid. The individual grains are jammed together like sand on a beach, forming a disordered, glassy or amorphous structure, and giving pastes their solid-like character. It is this "jamming together" that gives pastes some of their most unusual properties; this causes paste to demonstrate properties of fragile matter. Examples include starch pastes, toothpaste, mustard, and putty. In pharmacology, paste is a basic pharmaceutical form. It consists of a fatty base (e.g., petroleum jelly) and at least 25% of a solid substance (e.g., zinc oxide Zinc oxide is an inorganic compound with the formula . It is a white powder that is insoluble in water. ZnO is used as an additive in numero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fragile Matter
In materials science, fragile matter is a granular material that is jammed solid. Everyday examples include beans getting stuck in a hopper in a whole food shop, or milk powder getting jammed in an upside-down bottle. The term was coined by physicist Michael Cates, who asserts that such circumstances warrant a new class of materials. The jamming thus described can be unjammed by mechanical means, such as tapping or shaking the container, or poking it with a stick. Cates proposed that such jammed systems differ from ordinary solids in that if the direction of the applied stress changes, the jam will break up. Sometimes the change of direction required is very small. Perhaps the simplest example is a pile of sand, which is solid in the sense that the pile sustains its shape despite the force of gravity. Slight tilting or vibration is enough to enable the grains to shift, collapsing the pile. Not all jammed systems are fragile, i.e. foam. Shaving foam is jammed because the bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Materials
Material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geological origin or biological function. Materials science is the study of materials, their properties and their applications. Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials. New materials can be produced from raw materials by synthesis. In industry, materials are inputs to manufacturing processes to produce products or more complex materials. Historical elements Materials chart the history of humanity. The system of the three prehistoric ages (Stone Age, Bronze Age, Iron Age) were succeeded by historical ages: steel age in the 19th century, polymer age in the middle of the following century (plastic age) and silicon age in the second half of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Oxide
Zinc oxide is an inorganic compound with the formula . It is a white powder that is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, and first-aid tapes. Although it occurs naturally as the mineral zincite, most zinc oxide is produced synthetically. ZnO is a wide-band gap semiconductor of the II-VI semiconductor group. The native doping of the semiconductor due to oxygen vacancies or zinc interstitials is n-type. Other favorable properties include good transparency, high electron mobility, wide band gap, and strong room-temperature luminescence. Those properties make ZnO valuable for a variety of emerging applications: transparent electrodes in liquid crystal displays, energy-saving or heat-protecting windows, and electronics as thin-film transistors and lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum Jelly
Petroleum jelly, petrolatum, white petrolatum, soft paraffin, or multi-hydrocarbon, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons (with carbon numbers mainly higher than 25), originally promoted as a topical ointment for its healing properties. The Vaseline brand is a well known American brand of petroleum jelly since 1870. After petroleum jelly became a medicine-chest staple, consumers began to use it for cosmetic purposes and for many ailments including toenail fungus, genital rashes (non- STD), nosebleeds, diaper rash, and common colds. Its folkloric medicinal value as a "cure-all" has since been limited by better scientific understanding of appropriate and inappropriate uses. It is recognized by the U.S. Food and Drug Administration (FDA) as an approved over-the-counter (OTC) skin protectant and remains widely used in cosmetic skin care, where it is often loosely referred to as mineral oil. History Marco Polo in 1273 described the oil exportation of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmaceutical Form
Dosage forms (also called unit doses) are pharmaceutical drug products in the form in which they are marketed for use, with a specific mixture of active ingredients and inactive components (excipients), in a particular configuration (such as a capsule shell, for example), and apportioned into a particular dose. For example, two products may both be amoxicillin, but one is in 500 mg capsules and another is in 250 mg chewable tablets. The term unit dose can also sometimes encompass non-reusable ''packaging'' as well (especially when each drug product is individually packaged), although the FDA distinguishes that by ''unit-dose "packaging" or "dispensing"''. Depending on the context, ''multi(ple) unit dose'' can refer to distinct drug products ''packaged'' together, or to a ''single'' drug product containing multiple drugs and/or doses. The term dosage form can also sometimes refer ''only'' to the pharmaceutical formulation of a drug product's constituent drug substance(s) and any ble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Putty
Putty is a material with high plasticity, similar in texture to clay or dough, typically used in domestic construction and repair as a sealant or filler. Although some types of putty (typically those using linseed oil) slowly polymerise and become stiff, many putties can be reworked indefinitely, in contrast to other types of filler which typically set solid relatively rapidly. Chemical composition Putty, or lime putty, is made from a mixture of calcium oxide (CaO) and water (H2O) in proportions of 38% and 62% by weight respectively, as result, the solution forms hydrated lime (Ca(OH)2) which takes up about a half of the weight. The other putty mixture may be a calcium carbonate (CaCO3, 750-850 parts) based with a admixtures of CaO (ash calcium, 120-180 parts), white cement (40-60 parts), and talc powders in much lower concentrations (fractions). Applications Use in construction Putty has been used extensively in glazing for fixing and sealing panes of glass into wood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mustard (condiment)
Mustard is a condiment made from the seeds of a mustard plant (white/yellow mustard, '' Sinapis alba''; brown mustard, ''Brassica juncea''; or black mustard, ''Brassica nigra''). The whole, ground, cracked, or bruised mustard seeds are mixed with water, vinegar, lemon juice, wine, or other liquids, salt, and often other flavorings and spices, to create a paste or sauce ranging in color from bright yellow to dark brown. The seed itself has a strong, pungent, and somewhat bitter taste. The taste of mustard condiments ranges from sweet to spicy. Mustard is commonly paired with meats, vegetables and cheeses, especially as a condiment for sandwiches, hamburgers, and hot dogs. It is also used as an ingredient in many dressings, glazes, sauces, soups, and marinades. As a cream or as individual seeds, mustard is used as a condiment in the cuisine of India and Bangladesh, the Mediterranean, northern and southeastern Europe, Asia, the Americas, and Africa, making it one of the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toothpaste
Toothpaste is a paste or gel dentifrice used with a toothbrush to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from the teeth, assists in suppressing halitosis, and delivers active ingredients (most commonly fluoride) to help prevent tooth decay ( dental caries) and gum disease (gingivitis).American Dental Association Description of Toothpaste Owing to differences in composition and fluoride content, not all toothpastes are equally effective in maintaining oral health. The decline of tooth decay during the 20th century has been attributed to the introduction and regular use of fluoride-containing toothpastes worldwide. Large amounts of swallowed toothpaste can be toxic. Common colors for toothpaste include white (sometimes with colored stripes or green tint) and blue. Usefulness Toothpastes are generally useful to maintain dental health. Toothpastes containing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starch
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets, and is contained in large amounts in staple foods such as wheat, potatoes, maize (corn), rice, and cassava (manioc). Pure starch is a white, tasteless and odorless powder that is insoluble in cold water or alcohol. It consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight. Glycogen, the energy reserve of animals, is a more highly branched version of amylopectin. In industry, starch is often converted into sugars, for example by malting. These sugars may be fermented to produce ethanol in the manufacture of beer, whisky and biofuel. In addition, sugars produced from processed s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amorphous
In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid, glassy solid) is a solid that lacks the long-range order that is characteristic of a crystal. Etymology The term comes from the Greek language, Greek ''a'' ("without"), and ''morphé'' ("shape, form"). In some older articles and books, the term was used synonymously with glass. Today, "glassy solid" or "amorphous solid" is considered the overarching concept. Polymer, Polymers are often amorphous. Structure Amorphous materials have an internal structure comprising interconnected structural blocks that can be similar to the basic structural units found in the corresponding crystalline phase of the same compound. Unlike crystalline materials, however, no long-range order exists. Localized order in amorphous materials can be categorized as short or medium range order. By convention, short range order extends only to the nearest neighbor shell, typically only 1-2 atomic spacings. Medium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice ( crystalline solids, which include metals and ordinary ice), or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed. The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
