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Homogenization (chemistry)
Homogenization or homogenisation is any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout. This is achieved by turning one of the liquids into a state consisting of extremely small particles distributed uniformly throughout the other liquid. A typical example is the homogenization of milk, wherein the milk fat globules are reduced in size and dispersed uniformly through the rest of the milk. Definition Homogenization (from "homogeneous;" Greek, ''homogenes'': ''homos,'' same + ''genos,'' kind) is the process of converting two immiscible liquids (i.e. liquids that are not soluble, in all proportions, one in another) into an emulsion (Mixture of two or more liquids that are generally immiscible). Sometimes two types of homogenization are distinguished: primary homogenization, when the emulsion is created directly from separate liquids; and secondary homogenization, when the emulsion is created by the reduction in size of droplets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogenizing Valve
Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the Uniformity (chemistry), uniformity of a Chemical substance, substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, size, weight, height, distribution, texture, language, income, disease, temperature, radioactivity, architectural design, etc.); one that is heterogeneous is distinctly nonuniform in at least one of these qualities. Mixture, Heterogeneous Mixtures, in chemistry, is where certain elements are unwillingly combined and, when given the option, will separate. Etymology and spelling The words ''homogeneous'' and ''heterogeneous'' come from Medieval Latin ''homogeneus'' and ''heterogeneus'', from Ancient Greek ὁμογενής (''homogenēs'') and ἑτερογενής (''heterogenēs''), from ὁμός (''homos'', “same”) and ἕτερος (''heteros'', “other, another, different”) respectively, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herd
A herd is a social group of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is called ''herding''. These animals are known as gregarious animals. The term ''herd'' is generally applied to mammals, and most particularly to the grazing ungulates that classically display this behaviour. Different terms are used for similar groupings in other species; in the case of birds, for example, the word is '' flocking'', but ''flock'' may also be used for mammals, particularly sheep or goats. Large groups of carnivores are usually called '' packs'', and in nature a herd is classically subject to predation from pack hunters. Special collective nouns may be used for particular taxa (for example a flock of geese, if not in flight, is sometimes called a ''gaggle'') but for theoretical discussions of behavioural ecology, the generic term ''herd'' can be used for all such kinds of assemblage. The word ''herd'', as a noun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unit Operations
In chemical engineering and related fields, a unit operation is a basic step in a process. Unit operations involve a physical change or chemical transformation such as separation, crystallization, evaporation, filtration, polymerization, isomerization, and other reactions. For example, in milk processing, the following unit operations are involved: homogenization, pasteurization, and packaging. These unit operations are connected to create the overall process. A process may require many unit operations to obtain the desired product from the starting materials, or feedstocks. History Historically, the different chemical industries were regarded as different industrial processes and with different principles. Arthur Dehon Little developed the concept of "unit operations" to explain industrial chemistry processes in 1916. In 1923, William H. Walker, Warren K. Lewis and William H. McAdams wrote the book ''The Principles of Chemical Engineering'' and explained that the variety of ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Disruption
Cell disruption is a method or process for releasing biological molecules from inside a cell. Methods The production of biologically interesting molecules using cloning and culturing methods allows the study and manufacture of relevant molecules. Except for excreted molecules, cells producing molecules of interest must be disrupted. This page discusses various methods. Another method of disruption is called cell unroofing. Bead method A common laboratory-scale mechanical method for cell disruption uses glass, ceramic or steel beads, 0.1 to 2 mm in diameter, mixed with a sample suspended in aqueous media. First developed by Tim Hopkins in the late 1970s, the sample and bead mix is subjected to high level agitation by stirring or shaking. Beads collide with the cellular sample, cracking open the cell to release intercellular components. Unlike some other methods, mechanical shear is moderate during homogenization resulting in excellent membrane or subcellular preparations. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogenizer
A homogenizer is a piece of laboratory or industrial equipment used for the homogenization of various types of material, such as tissue, plant, food, soil, and many others. Many different models have been developed using various physical technologies for disruption. The mortar and pestle, already used for thousands of years, is a standard tool even in modern laboratories. More modern solutions are based on blender type instruments, bead mills, ultrasonic treatment (also sonication), rotor-stator mechanical, high pressure, and many other physical forces. While there are many application overlaps between methods, each homogenization method has distinct advantages and disadvantages. There are often many different names for the same piece of mechanical homogenizing equipment, including Cell Lysor, Disperser, High Shear Mixer, Homogenizer, Polytron, Rotor Stator Homogenizer, Sonicator or Tissue Tearor. Cell fractionation is done by homogenizer to release the organelles from cell. Wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Pressure Cell Press
The French pressure cell press, or French press, is an apparatus used in biological experimentation to disrupt the plasma membrane of cells by passing them through a narrow valve under high pressure. The French Press can also be used for disintegration of chloroplasts, homogenates of animal tissue, and other biological particles. It is capable of disrupting cell walls while leaving the cell nucleus undisturbed. The French press was invented by Charles Stacy French of the Carnegie Institution of Washington. The press uses an external hydraulic pump to drive a piston within a larger cylinder that contains the liquid sample. The highly pressurized sample is then squeezed past a needle valve. As the sample passes through the valve, the fluid experiences shear stress and decompression, causing cellular disruption. The major components of a French press are made of stainless steel to prevent sample contamination. A French press is commonly used to break the resilient plasma membran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Homogenizer
A sonicator at the Weizmann Institute of Science during sonicationSonication is the act of applying sound energy to agitate particles in a sample, for various purposes such as the extraction of multiple compounds from plants, microalgae and seaweeds. Ultrasonic frequencies (> 20 kHz) are usually used, leading to the process also being known as ultrasonication or ultra-sonication. In the laboratory, it is usually applied using an ''ultrasonic bath'' or an ''ultrasonic probe'', colloquially known as a ''sonicator''. In a paper machine, an ultrasonic foil can distribute cellulose fibres more uniformly and strengthen the paper. Effects Sonication has numerous effects, both chemical and physical. The chemical effects of ultrasound are concerned with understanding the effect of sonic waves on chemical systems, this is called sonochemistry. The chemical effects of ultrasound do not come from a direct interaction with molecular species. Studies have shown that no direct coupl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butterfat
Butterfat or milkfat is the fatty portion of milk. Milk and cream are often sold according to the amount of butterfat they contain. Composition Butterfat is mainly composed of triglycerides. Each triglyceride contains three fatty acids. Butterfat triglycerides contain the following amounts of fatty acids (by mass fraction):The quote values vary by 1–3% according to the source: Butterfat contains about 3% trans fat, which is slightly less than 0.5 grams per US tablespoon. Trans fats occur naturally in meat and milk from ruminants. The predominant kind of trans fat found in milk is vaccenic fatty acid. Trans fats may be also found in some industrially produced foods, such as shortenings obtained by hydrogenation of vegetable oils. In light of recognized scientific evidence, nutritional authorities consider all trans fats equally harmful for health and recommend that their consumption be reduced to trace amounts. However, two Canadian studies have shown that vaccenic acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raw Milk
Raw milk or unpasteurized milk is milk that has not been pasteurized, a process of heating liquid foods to kill pathogens for safe consumption and extending the shelf life. Proponents of raw milk have asserted numerous supposed benefits to consumption, including better flavor, better nutrition, contributions to the building of a healthy immune system and protection from allergies. However, no clear benefit to consumption has been found, and the medical community notes there is increased risk of contracting dangerous milk borne diseases from these products substantial evidence of this increased risk, combined with a lack of any clear benefit, has led countries around the world to either prohibit the sale of raw milk or require warning labels on packaging when sold. In countries where it is available for sale, its availability and regulations around its sale vary. In the EU, member states can prohibit or restrict the sale of raw milk, but it is not banned outright; in some member ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dairies
A dairy is a business enterprise established for the harvesting or processing (or both) of animal milk – mostly from cows or buffaloes, but also from goats, sheep, horses, or camels – for human consumption. A dairy is typically located on a dedicated dairy farm and milk or in a section of a multi-purpose farm (mixed farm) that is concerned with the harvesting of milk. As an attributive, the word ''dairy'' refers to milk-based products, derivatives and processes, and the animals and workers involved in their production: for example dairy cattle, dairy goat. A dairy farm produces milk and a dairy factory processes it into a variety of dairy products. These establishments constitute the global dairy industry, part of the food industry. Terminology Terminology differs between countries. In the United States, for example, an entire dairy farm is commonly called a "dairy". The building or farm area where milk is harvested from the cow is often called a "milking parlor" or "parlor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC Press
The CRC Press, LLC is an American publishing group that specializes in producing technical books. Many of their books relate to engineering, science and mathematics. Their scope also includes books on business, forensics and information technology. CRC Press is now a division of Taylor & Francis, itself a subsidiary of Informa. History The CRC Press was founded as the Chemical Rubber Company (CRC) in 1903 by brothers Arthur, Leo and Emanuel Friedman in Cleveland, Ohio, based on an earlier enterprise by Arthur, who had begun selling rubber laboratory aprons in 1900. The company gradually expanded to include sales of laboratory equipment to chemists. In 1913 the CRC offered a short (116-page) manual called the ''Rubber Handbook'' as an incentive for any purchase of a dozen aprons. Since then the ''Rubber Handbook'' has evolved into the CRC's flagship book, the '' CRC Handbook of Chemistry and Physics''. In 1964, Chemical Rubber decided to focus on its publishing ventures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixture
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 Solution (chemistry), solutions, Suspension (chemistry), suspensions and colloids. Mixtures are one product of mechanically blending or mixing chemical substances such as chemical element, elements and Compound (chemistry), 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 separation process, separated into their components by using physical (mechanical or thermal) means. Azeotropes are one kind of mixture that usually poses considerable diffi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
