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Directional Freezing
Directional freezing freezes from only one direction. Directional freezing can freeze water, from only one direction or side of a container, into clear ice. Directional freezing in a domestic freezer can be done by putting water in a insulated container so that the water freezes from the top down, and removing before fully frozen, so that the minerals in the water are not frozen. F Hoffmann La Roche AG, Roche Diagnostics GmbH has a 2017 directional freezing patent for drying solid material. See also * Aquamelt * Beluga whale * Clear ice * Hydrogel * Freeze-casting§Static vs. dynamic freezing profiles * Molecular self-assembly In chemistry and materials science, molecular self-assembly is the process by which molecules adopt a defined arrangement without guidance or management from an outside source. There are two types of self-assembly: intramolecular and intermole ... Further reading * * * * * * * * References Phase transitions Cryobiology Molecular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freezing
Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid or the liquid content of a substance, usually due to cooling. For most substances, the melting and freezing points are the same temperature; however, certain substances possess differing solid-liquid transition temperatures. For example, agar displays a hysteresis in its melting point and freezing point. It melts at 85 °C (185 °F) and solidifies from 32 °C to 40 °C (89.6 °F to 104 °F). Crystallization Most liquids freeze by crystallization, formation of crystalline solid from the uniform liquid. This is a first-order thermodynamic phase transition, which means that as long as solid and liquid coexist, the temperature of the whole system remains very nearly equal to the melting point due to the slow re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clear Ice
Clear ice refers to a solid precipitation which forms when air temperature is between and and there are supercooled, relatively large drops of water (from freezing fog). A rapid accretion and a slow dissipation of latent heat of fusion favor the formation of a transparent ice coating, without air or other impurities. A similar phenomenon occurs when freezing rain or drizzle hit a surface and is called glaze. Clear ice, when formed on the ground, is often called black ice, and can be extremely hazardous. Clear ice is denser and more homogeneous than hard rime; like rime, however, clear ice accumulates on branches and overhead lines, where it is particularly dangerous due to its relatively high density. See also *Ice storm *SAS Flight 751 Scandinavian Airlines System Flight 751 was a regularly scheduled Scandinavian Airlines passenger flight from Stockholm, Sweden, to Warsaw, Poland, via Copenhagen, Denmark. On 27 December 1991, a McDonnell Douglas MD-81 operating the fli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Men's Journal
''Men's Journal'' is an American monthly men's lifestyle magazine focused on outdoor recreation and comprising editorials on the outdoors, environmental issues, health and fitness, style and fashion, and gear. It was founded in 1992 by Jann Wenner of Wenner Media, who sought to create a publication for "active, accomplished men to fuel an adventurous and discerning lifestyle". Wenner Media sold ''Men's Journal'' to American Media, Inc. in 2017. Format Each issue of ''Men's Journal'' is divided into 3 subsections: *Notebook – encompasses the latest trends, products, destinations, style & design *Blueprint – provides the latest science articles and expert advice on diet, fitness, and exercise *Gear Lab – a monthly buyer's guide of tested and approved essentials: tech, tools and toys. ''Men's Journal'' hires experts and professionals to examine the products; the best performing gear throughout the year get highlighted in the December issue, "Gear of the Year". History On April ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Google Patents
Google Patents is a search engine from Google that indexes patents and patent applications. Contents Google Patents indexes more than 87 million patents and patent applications with full text from 17 patent offices, including: * United States Patent and Trademark Office (USPTO), * European Patent Office (EPO), * China's National Intellectual Property Administration (CNIPA), * Japan Patent Office (JPO), * Korean Intellectual Property Office (KIPO), * World Intellectual Property Organization (WIPO), * Deutsches Patent- und Markenamt (DPMA), * Canadian Intellectual Property Office (CIPO), * Rospatent, * Intellectual Property Office (United Kingdom), * National Institute of Industrial Property (France), * the Netherlands Patent Office, * offices of Spain, Belgium, Denmark, Finland, and Luxembourg. These documents include the entire collection of granted patents and published patent applications from each database (which belong to the public domain). US patent documents date back to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquamelt
An aquamelt is a naturally hydrated polymeric material that is able to solidify at environmental temperatures through a controlled stress input (be it mechanical or chemical). They are unique in being able to “lock in” work applied to them through an alteration in hydrogen bonding, which enables them to be processed with approximately 1000 times less energy than standard polymers. This has been recently shown for an archetypal biopolymer, silk, however the mechanism for solidification is thought to be inherent to many other biological materials. Discovery and mechanism Aquamelts were defined as a new class of polymeric material as a result of a comparison between the spinning feedstock of the Chinese silkworm (''Bombyx mori'') and molten high-density polyethylene (HDPE) using shear induced polarised light imaging (SIPLI). The current understanding of shear induced fibrillation requires polymer chains to undergo the following series of steps i) long-chain molecules are stretche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beluga Whale
The beluga whale () (''Delphinapterus leucas'') is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus ''Delphinapterus''. It is also known as the white whale, as it is the only cetacean to regularly occur with this colour; the sea canary, due to its high-pitched calls; and the melonhead, though that more commonly refers to the melon-headed whale, which is an oceanic dolphin. The beluga is adapted to life in the Arctic, with anatomical and physiological characteristics that differentiate it from other cetaceans. Amongst these are its all-white colour and the absence of a dorsal fin, which allows it to swim under ice with ease. It possesses a distinctive protuberance at the front of its head which houses an animal echolocation, echolocation organ called the Melon (whale), melon, which in this species is large and deformable. The beluga's body size is between that of a dolphin and a true ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clear Ice
Clear ice refers to a solid precipitation which forms when air temperature is between and and there are supercooled, relatively large drops of water (from freezing fog). A rapid accretion and a slow dissipation of latent heat of fusion favor the formation of a transparent ice coating, without air or other impurities. A similar phenomenon occurs when freezing rain or drizzle hit a surface and is called glaze. Clear ice, when formed on the ground, is often called black ice, and can be extremely hazardous. Clear ice is denser and more homogeneous than hard rime; like rime, however, clear ice accumulates on branches and overhead lines, where it is particularly dangerous due to its relatively high density. See also *Ice storm *SAS Flight 751 Scandinavian Airlines System Flight 751 was a regularly scheduled Scandinavian Airlines passenger flight from Stockholm, Sweden, to Warsaw, Poland, via Copenhagen, Denmark. On 27 December 1991, a McDonnell Douglas MD-81 operating the fli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogel
A hydrogel is a crosslinked hydrophilic polymer that does not dissolve in water. They are highly absorbent yet maintain well defined structures. These properties underpin several applications, especially in the biomedical area. Many hydrogels are synthetic, but some are derived from nature. The term 'hydrogel' was coined in 1894. Chemistry Classification The crosslinks which bond the polymers of a hydrogel fall under two general categories: physical and chemical. Chemical hydrogels have covalent cross-linking bonds, whereas physical hydrogels have non-covalent bonds. Chemical hydrogels result in strong irreversible gels due to the covalent bonding, and they may also possess harmful properties which makes them unfavourable for medical applications. Physical hydrogels on the other hand have high biocompatibility, aren’t toxic, and are also easily reversible, by simply changing an external stimulus such as pH or temperature; thus they are favourable for use in medical applicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freeze-casting
Freeze-casting, also frequently referred to as ''ice-templating'', or ''freeze alignment'', is a technique that exploits the highly anisotropic solidification behavior of a solvent (generally water) in a well-dispersed slurry to controllably template a directionally porous ceramic. By subjecting an aqueous slurry to a directional temperature gradient, ice crystals will nucleate on one side of the slurry and grow along the temperature gradient. The ice crystals will redistribute the suspended ceramic particles as they grow within the slurry, effectively templating the ceramic. Once solidification has ended, the frozen, templated ceramic is placed into a freeze-dryer to remove the ice crystals. The resulting green body contains anisotropic macropores in a replica of the sublimated ice crystals and micropores found between the ceramic particles in the walls. This structure is often sintered to consolidate the particulate walls and provide strength to the porous material. The porosit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Self-assembly
In chemistry and materials science, molecular self-assembly is the process by which molecules adopt a defined arrangement without guidance or management from an outside source. There are two types of self-assembly: intramolecular and intermolecular. Commonly, the term ''molecular self-assembly'' refers to the former, while the latter is more commonly called ''folding''. Supramolecular systems Molecular self-assembly is a key concept in supramolecular chemistry. This is because assembly of molecules in such systems is directed through non-covalent interactions (e.g., hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, pi-stacking interactions, and/or electrostatic) as well as electromagnetic interactions. Common examples include the formation of colloids, biomolecular condensates, micelles, vesicles, liquid crystal phases, and Langmuir monolayers by surfactant molecules. Further examples of supramolecular assemblies demonstrate that a variety of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Transitions
In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma. A phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change as a result of the change of external conditions, such as temperature or pressure. This can be a discontinuous change; for example, a liquid may become gas upon heating to its boiling point, resulting in an abrupt change in volume. The identification of the external conditions at which a transformation occurs defines the phase transition point. Types of phase transition At the phase transition point for a substance, for instance the boiling point, the two phases involved - liquid and vapor, have identic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryobiology
Cryobiology is the branch of biology that studies the effects of low temperatures on living things within Earth's cryosphere or in science. The word cryobiology is derived from the Greek words κρῧος ryos "cold", βίος ios "life", and λόγος ogos "word". In practice, cryobiology is the study of biological material or systems at temperatures below normal. Materials or systems studied may include proteins, cells, tissues, organs, or whole organisms. Temperatures may range from moderately hypothermic conditions to cryogenic temperatures. Areas of study At least six major areas of cryobiology can be identified: 1) study of cold-adaptation of microorganisms, plants ( cold hardiness), and animals, both invertebrates and vertebrates (including hibernation), 2) cryopreservation of cells, tissues, gametes, and embryos of animal and human origin for (medical) purposes of long-term storage by cooling to temperatures below the freezing point of water. This usually requires the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
