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Powder Mixture
A powder is an assembly of dry particles dispersed in air. If two different powders are mixed perfectly, theoretically, three types of powder mixtures can be obtained: the random mixture, the ordered mixture or the interactive mixture. Different powder types A powder is called free-flowing if the particles do not stick together. If particles are cohesive, they cling to one another to form aggregates. The significance of cohesion increases with decreasing size of the powder particles; particles smaller than 100 µm are generally cohesive. Random mixture A random mixture can be obtained if two different free-flowing powders of approximately the same particle size, density and shape are mixed (see figure A). Only primary particles are present in this type of mixture, i.e., the particles are not cohesive and do not cling to one another. The mixing time will determine the quality of the random mixture. However, if powders with particles of different size, density or shape are m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powder (substance)
A powder is a dry, bulk solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms ''powder'' and ''granular'' are sometimes used to distinguish separate classes of material. In particular, ''powders'' refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. ''Granulars'' refers to the coarser granular materials that do not tend to form clumps except when wet. Types Many manufactured goods come in powder form, such as flour, sugar, ground coffee, powdered milk, copy machine toner, gunpowder, cosmetic powders, and some pharmaceuticals. In nature, dust, fine sand and snow, volcanic ash, and the top layer of the lunar regolith are also examples. Because of their importance to industry, medicine and earth science, powders have been studied in great detail by chemical engineers, mechanical engi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insufflation (medicine), inhalation, drug injection, injection, smoking, ingestion, absorption (skin), absorption via a dermal patch, patch on the skin, suppository, or sublingual administration, dissolution under the tongue. In pharmacology, a drug is a chemical substance, typically of known structure, which, when administered to a living organism, produces a biological effect. A pharmaceutical drug, also called a medication or medicine, is a chemical substance used to pharmacotherapy, treat, cure, preventive healthcare, prevent, or medical diagnosis, diagnose a disease or to promote well-being. Traditionally drugs were obtained through extraction from medicinal plants, but more recently also by organic synthesis. Pharmaceutical drugs may be used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food Technology
Food technology is a branch of food science that deals with the production, preservation, quality control and research and development of the food products. Early scientific research into food technology concentrated on food preservation. Nicolas Appert’s development in 1810 of the canning process was a decisive event. The process wasn't called canning then and Appert did not really know the principle on which his process worked, but canning has had a major impact on food preservation techniques. Louis Pasteur's research on the spoilage of wine and his description of how to avoid spoilage in 1864 was an early attempt to apply scientific knowledge to food handling. Besides research into wine spoilage, Pasteur researched the production of alcohol, vinegar, wines and beer, and the souring of milk. He developed pasteurization—the process of heating milk and milk products to destroy food spoilage and disease-producing organisms. In his research into food technology, Pasteur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granularity Of Materials
Granularity (also called graininess), the condition of existing in granules or grains, refers to the extent to which a material or system is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is subdivided, or the extent to which groups of smaller indistinguishable entities have joined together to become larger distinguishable entities. Precision and ambiguity Coarse-grained materials or systems have fewer, larger discrete components than fine-grained materials or systems. * A coarse-grained description of a system regards large subcomponents. * A fine-grained description regards smaller components of which the larger ones are composed. The concepts granularity, coarseness, and fineness are relative; and are used when comparing systems or descriptions of systems. An example of increasingly fine granularity: a list of nations in the United Nations, a list of all states/provinces in those nations, a list of all cities in those states, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Food And Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, caffeine products, dietary supplements, Prescription drug, prescription and Over-the-counter drug, over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), cosmetics, Animal feed, animal foods & feed and Veterinary medicine, veterinary products. The FDA's primary focus is enforcement of the Federal Food, Drug, and Cosmetic Act (FD&C), but the agency also enforces other laws, notably Section 361 of the Public Health Service Act, as well as associated regulations. Much of this regulatory-enforcement work is not d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Administration
Nasal administration, popularly known as snorting, is a route of administration in which drugs are insufflated through the nose. It can be a form of either topical administration or systemic administration, as the drugs thus locally delivered can go on to have either purely local or systemic effects. Nasal sprays are locally acting drugs such as decongestants for cold and allergy treatment, whose systemic effects are usually minimal. Examples of systemically active drugs available as nasal sprays are migraine drugs, rescue medications for overdose and seizure emergencies, nicotine replacement, and hormone treatments. Advantages with nasal systemic drug delivery The nasal cavity is covered by a thin mucosa which is well vascularised. Therefore, a drug molecule can be transferred quickly across the single epithelial cell layer directly to the systemic blood circulation without first-pass hepatic and intestinal metabolism. The effect is often reached within 5 min for smaller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soluble
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be "miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. M. Diepen (1966): "Gas—Gas Equilibria". ''Journal of Chemical Physics'', vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cohesion (chemistry)
Cohesion (), also called cohesive attraction or cohesive force, is the action or property of like molecules sticking together, being mutually attractive. It is an intrinsic property of a substance that is caused by the shape and structure of its molecules, which makes the distribution of surrounding electrons irregular when molecules get close to one another, creating electrical attraction that can maintain a microscopic structure such as a water drop. Cohesion allows for surface tension, creating a "solid-like" state upon which light-weight or low-density materials can be placed. Water, for example, is strongly cohesive as each molecule may make four hydrogen bonds to other water molecules in a tetrahedral configuration. This results in a relatively strong Coulomb force between molecules. In simple terms, the polarity (a state in which a molecule is oppositely charged on its poles) of water molecules allows them to be attracted to each other. The polarity is due to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogeneous (chemistry)
In chemistry, a mixture is a material made up of two or more different chemical substances which are not chemically bonded. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids. Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup. Despite the fact that there are no chemical changes to its constituents, the physical properties of a mixture, such as its melting point, may differ from those of the components. Some mixtures can be separated into their components by using physical (mechanical or thermal) means. Azeotropes are one kind of mixture that usually poses considerable difficulties regarding the separation processes required to obtain their constituents (physical or chemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Segregation
In particle segregation, particulate solids, and also quasi-solids such as foams, tend to segregate by virtue of differences in the size, and also physical properties such as volume, density, shape and other properties of particles of which they are composed. Segregation occurs mainly during the powder handling and it is pronounced in free-flowing powders. One of the effective methods to control granular segregation is to make mixture's constituents sticky using a coating agent. This is especially useful when a highly active ingredient, like an enzyme, is present in the mixture. Powders that are inherently not free flowing and exhibit high levels of cohesion/adhesion between the compositions are sometimes difficult to mix as they tend to form agglomerates. The clumps of particles can be broken down in such cases by the use of mixtures that generate high shear force In solid mechanics, shearing forces are unaligned forces acting on one part of a body in a specific directio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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