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Topic Review
Vitamin D in Dairy Products
The term Vitamin D was created in 1922, describing a vitamin able to promote calcium deposition. Vitamin D in nature is available as ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3).
  • 3.6K
  • 05 Nov 2020
Topic Review
76 Mm Gun M1
The 76 mm gun M1 was an American World War II–era tank gun developed by the U.S Ordnance Department in 1942 to supplement the 75 mm gun on the basic Medium tank M4. It was also used to arm the 76 mm Gun Motor Carriage M18 tank destroyer. Although the gun was tested in early August 1942 and classified on August 17, 1942, it was not until August 1943 that the Ordnance Department developed a mounting for the M4 tank that the tank forces would accept. It was not accepted for combat until July 1944. In January 1943, the decision was made to mount the 76 mm on the vehicle that would become the M18. By May 1944, it was being combat tested as the T70.
  • 3.6K
  • 11 Nov 2022
Topic Review
Livery
A livery /ˈlɪvəri/ is a uniform, insignia or symbol adorning, in a non-military context, a person, an object or a vehicle that denotes a relationship between the wearer of the livery and an individual or corporate body. Often, elements of the heraldry relating to the individual or corporate body feature in the livery. Alternatively, some kind of a personal emblem or badge, or a distinctive colour, is featured. The word itself derives from the French livrée, meaning dispensed, handed over. Most often it would indicate that the wearer of the livery was a servant, dependant, follower or friend of the owner of the livery, or, in the case of objects, that the object belonged to them. In the late medieval phenomenon of bastard feudalism, livery badges worn by the "retainers" of great lords, sometimes in effect private armies, became a great political concern in England.
  • 3.6K
  • 01 Dec 2022
Topic Review
Serendipity as a strategic advantage
Serendipity is defined as an ability to notice, evaluate, and take advantage of unexpected information for survival purposes (both natural and social). Based on this definition, Nancy K. Napier and Vuong Quan Hoang propose a framework to develop the notion of serendipity as a strategic advantage (or competitive advantage), both in practice and in research.
  • 3.6K
  • 06 May 2024
Topic Review
Object-Relational Database
An object-relational database (ORD), or object-relational database management system (ORDBMS), is a database management system (DBMS) similar to a relational database, but with an object-oriented database model: objects, classes and inheritance are directly supported in database schemas and in the query language. In addition, just as with pure relational systems, it supports extension of the data model with custom data types and methods. An object-relational database can be said to provide a middle ground between relational databases and object-oriented databases. In object-relational databases, the approach is essentially that of relational databases: the data resides in the database and is manipulated collectively with queries in a query language; at the other extreme are OODBMSes in which the database is essentially a persistent object store for software written in an object-oriented programming language, with a programming API for storing and retrieving objects, and little or no specific support for querying.
  • 3.6K
  • 04 Nov 2022
Topic Review
Authenticity in Art
Authenticity in art is the different ways in which a work of art or an artistic performance may be considered authentic. Denis Dutton distinguishes between nominal authenticity and expressive authenticity. The first refers to the correct identification of the author of a work of art, to how closely a performance of a play or piece of music conforms to the author's intention, or to how closely a work of art conforms to an artistic tradition. The second sense refers to how much the work possesses original or inherent authority, how much sincerity, genuineness of expression, and moral passion the artist or performer puts into the work. A quite different concern is the authenticity of the experience, which may be impossible to achieve. A modern visitor to a museum may not only see an object in a very different context from that which the artist intended, but may be unable to understand important aspects of the work. The authentic experience may be impossible to recapture. Authenticity is a requirement for inscription upon the UNESCO World Heritage List. According to the Nara Document on Authenticity, it can be expressed through 'form and design; materials and substance; use and function; traditions and techniques; location and setting; spirit and feeling; and other internal and external factors.'
  • 3.6K
  • 09 Nov 2022
Topic Review
Bio-Oil
Bio-oil is a the liquid phase obtained from the pyrolysis of biomass. The composition and amount of bio-oil generated depend not only on the type of the biomass but also on the conditions under which pyrolysis is performed. Most fossil fuels can be replaced by bio-oil-derived products. Thus, bio-oil can be used directly or co-fed along with fossil fuels in boilers, transformed into fuel for car engines by hydrodeoxygenation or even used as a more suitable source for hydrogen production than biomass. On the other hand, due to its rich composition in compounds resulting from the pyrolysis of cellulose, hemicellulose and lignin, bio-oil co-acts as a source of various value-added chemicals such as aromatic compounds.
  • 3.6K
  • 12 May 2021
Topic Review
Deformation (Engineering)
In engineering, deformation refers to the change in size or shape of an object. Displacements are the absolute change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain is the relative internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of distortion of the cube. Strains are related to the forces acting on the cube, which are known as stress, by a stress-strain curve. The relationship between stress and strain is generally linear and reversible up until the yield point and the deformation is elastic. The linear relationship for a material is known as Young's modulus. Above the yield point, some degree of permanent distortion remains after unloading and is termed plastic deformation. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure by structural analysis. Engineering stress and engineering strain are approximations to the internal state that may be determined from the external forces and deformations of an object, provided that there is no significant change in size. When there is a significant change in size, the true stress and true strain can be derived from the instantaneous size of the object. In the figure it can be seen that the compressive loading (indicated by the arrow) has caused deformation in the cylinder so that the original shape (dashed lines) has changed (deformed) into one with bulging sides. The sides bulge because the material, although strong enough to not crack or otherwise fail, is not strong enough to support the load without change. As a result, the material is forced out laterally. Internal forces (in this case at right angles to the deformation) resist the applied load. The concept of a rigid body can be applied if the deformation is negligible.
  • 3.6K
  • 24 Oct 2022
Topic Review
Hydrometallurgy of Lithium Batteries
Spent lithium batteries can cause pollution to the soil and seriously threaten the safety and property of people. They contain valuable metals, such as cobalt and lithium, which are nonrenewable resources, and their recycling and treatment have important economic, strategic, and environmental benefits. The hydrometallurgy process uses reagents such as hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), phosphoric acid (H3PO4), organic acids, and hydrogen peroxide (H2O2) to extract and separate the cathode metals, usually operating below 100 °C, and can recover lithium in addition to the other transition metals.
  • 3.6K
  • 15 Mar 2022
Topic Review
Properties and Synthesis of Photocatalysts
The photocatalysts must be characterized by the ability to absorb radiation from a wide spectral range of light, the appropriate position of the semiconductor energy bands in relation to the redox reaction potentials, and the long diffusion path of charge carriers, besides the thermodynamic, electrochemical, and photoelectrochemical stabilities.
  • 3.6K
  • 30 Dec 2022
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