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Deacidification
Mass deacidification is a term used in library and information science as one possible measure against the degradation of paper in old books, the so-called "slow fires". The goal of the process is to increase the pH of acidic paper. Although acid-free paper has become more common, a large body of acidic paper still exists in books made after the 1850s; this is because of its cheaper and simpler production methods. Acidic paper, especially when exposed to light, air pollution, or high relative humidity, yellows and becomes brittle over time. During mass deacidification an alkaline agent is deposited in the paper to neutralize existing acid and prevent further decay. Mass deacidification is intended for objects on acidic paper that will be lost if no action is performed. History of research and process development Mass deacidification — along with microfilm and lamination — was developed during the early and mid-20th century as a response to the chemical process of h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Oxide
Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H2O → Mg(OH)2), but it can be reversed by heating it to remove moisture. Magnesium oxide was historically known as magnesia alba (literally, the white mineral from Magnesia), to differentiate it from ''magnesia negra'', a black mineral containing what is now known as manganese. Related oxides While "magnesium oxide" normally refers to MgO, the compound magnesium peroxide MgO2 is also known. According to evolutionary crystal structure prediction, MgO2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and a semiconducting suboxide Mg3O2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a model sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid-free Paper
Acid-free paper is paper that, if infused in water, yields a neutral or basic (chemistry), basic pH (7 or slightly greater). It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin- and sulfur-free. Acid-free paper addresses the problem of Preservation (library and archival science), preserving documents and Conservation (cultural heritage), preserving artwork for long periods. Overview Paper made from wood-based pulp that has not had its lignin removed turns yellow, becomes brittle, and deteriorates over time. When exposed to light and/or heat, the molecules in the acidic paper will break down even faster. Acidic wood-pulp paper became commonplace in the late 19th century, and in the 1930s William Barrow (chemist), William Barrow (a chemist and librarian) published a report about the deterioration of acidic paper in the libraries. For fear of the gradual disintegration of written materials, measures have since ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethylzinc
Diethylzinc (C2H5)2Zn, or DEZ, is a highly pyrophoric and reactive organozinc compound consisting of a zinc center bound to two ethyl groups. This colourless liquid is an important reagent in organic chemistry. It is available commercially as a solution in hexanes, heptane, or toluene, or as a pure liquid. Synthesis Edward Frankland first reported the compound in 1848 from zinc and ethyl iodide, the first organozinc compound discovered. He improved the synthesis by using diethyl mercury as starting material. The contemporary synthesis consists of the reaction of a 1:1 mixture of ethyl iodide and ethyl bromide with a zinc-copper couple, a source of reactive zinc. Structure The compound crystallizes in a tetragonal body-centered unit cell of space group symmetry I41md. In the solid-state diethylzinc shows nearly linear Zn centres. The Zn-C bonds measure 194.8(5) pm, while the C-Zn-C angle is slightly bent with 176.2(4)°. The structure of the gas-phase shows a very similar Zn-C d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Library And Information Science
Library and information science(s) or studies (LIS) is an interdisciplinary field of study that deals generally with organization, access, collection, and protection/regulation of information, whether in physical (e.g. art, legal proceedings, etc.) or digital forms. In spite of various trends to merge the two fields, some consider the two original disciplines, library science and information science, to be separate. However, it is common today to use the terms synonymously or to drop the term "library" and to speak about ''information departments'' or ''I-schools''. There have also been attempts to revive the concept of documentation and to speak of Library, information and documentation studies (or science). History By the late 1960s, mainly due to the meteoric rise of human computing power and the new academic disciplines formed therefrom, academic institutions began to add the term "information science" to their names. The first school to do this was at the University ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AkzoNobel
Akzo Nobel N.V., stylized as AkzoNobel, is a Dutch multinational company which creates paints and performance coatings for both industry and consumers worldwide. Headquartered in Amsterdam, the company has activities in more than 80 countries, and employs over 32,000 people. Sales in 2020 were €8.5 billion. History AkzoNobel has a long history of mergers and divestments. Parts of the current company can be traced back to 17th-century companies. The milestone mergers and divestments are the formation of AKZO in 1969, the merger with Nobel Industries in 1994 forming Akzo Nobel, and the divestment of its pharmaceutical business and the merger with ICI in 2007/2008 resulting in current-day AkzoNobel. History and formation of Akzo Akzo was formed in 1969 as merger of Algemene Kunstzijde Unie (AKU) and Koninklijke Zout Organon (KZO). The AKU was formed in 1929 when the Vereinigte Glanzstoff Fabrike (est. 1899) and Nederlandse Kunstzijdefabriek (ENKA, est. 1911) merged, forming Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservation Survey
Preservation survey (also known as condition survey, conservation needs survey or preservation assessment) is the process of collecting and analyzing data about the physical condition of library materials. Preservation surveys are used by libraries to determine the condition of their collections and identify necessary actions for preserving, conserving or repairing materials. They are most often conducted at research and university libraries. Preservation surveys are often the first step when planning and implementing a preservation program in a library. By collecting data and compiling statistics about a collection’s condition, library staff can determine environmental threats and preservation needs. It is also possible to use the resulting data to predict future deterioration. Since preservation needs usually well exceed an institution’s resources, the data acquired in an assessment can aid libraries in establishing priorities in regard to deteriorating materials. As Ross ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulp (paper)
Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemical or plant-based additives, pulp is the major raw material used in papermaking and the industrial production of other paper products. History Before the widely acknowledged invention of papermaking by Cai Lun in China around 105 AD, paper-like writing materials such as papyrus and amate were produced by ancient civilizations using plant materials which were largely unprocessed. Strips of bark or bast material were woven together, beaten into rough sheets, dried, and polished by hand. Pulp used in modern and traditional papermaking is distinguished by the process which produces a finer, more regular slurry of cellulose fibers which are pulled out of solution by a screen and dried to form sheets or rolls. The earliest paper produced in China consisted of bast fibers from the paper mulberr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, or currency and security paper, or in a number of industrial and construction processes. The papermaking process developed in east Asia, probably China, at least as early as 105 CE, by the Han court eunuch Cai Lun, although the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservation (library And Archival Science)
In Library science, library and archival science, preservation is a set of preventive conservation activities aimed at prolonging the life of a record, book, or object while making as few changes as possible. Preservation activities vary widely and may include monitoring the condition of items, maintaining the temperature and humidity in collection storage areas, writing a plan in case of emergencies, digitizing items, writing relevant metadata, and increasing accessibility. Preservation, in this definition, is practiced in a library or an archive by a librarian, archivist, or other professional when they perceive a record is in need of maintenance. Preservation should be distinguished from interventive Conservation and restoration of books, manuscripts, documents and ephemera, conservation and restoration, which refers to the treatment and repair of individual items to slow the process of decay, or restore them to a usable state. Preventive conservation is occasionally used int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry Ransom Humanities Research Center
The Harry Ransom Center (until 1983 the Humanities Research Center) is an archive, library and museum at the University of Texas at Austin, specializing in the collection of literary and cultural artifacts from the Americas and Europe for the purpose of advancing the study of the arts and humanities. The Ransom Center houses 36 million literary manuscripts, one million rare books, five million photographs, and more than 100,000 works of art. The center has a reading room for scholars and galleries which display rotating exhibitions of works and objects from the collections. In the 2015–16 academic year, the center hosted nearly 6,000 research visits resulting in the publication of over 145 books. History Harry Ransom founded the Humanities Research Center in 1957 with the ambition of expanding the rare books and manuscript holdings of the University of Texas. He acquired the Edward Alexander Parsons Collection, the T. Edward Hanley Collection, and the Norman Bel Geddes Collect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Archives And Records Administration
The National Archives and Records Administration (NARA) is an " independent federal agency of the United States government within the executive branch", charged with the preservation and documentation of government and historical records. It is also tasked with increasing public access to those documents which make up the National Archive. NARA is officially responsible for maintaining and publishing the legally authentic and authoritative copies of acts of Congress, presidential directives, and federal regulations. NARA also transmits votes of the Electoral College to Congress. It also examines Electoral College and Constitutional amendment ratification documents for prima facie legal sufficiency and an authenticating signature. The National Archives, and its publicly exhibited Charters of Freedom, which include the original United States Declaration of Independence, United States Constitution, United States Bill of Rights, and many other historical documents, is headquarte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Solution
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be represented as . The word ''aqueous'' (which comes from ''aqua'') means pertaining to, related to, similar to, or dissolved in, water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Since water is frequently used as the solvent in experiments, the word solution refers to an aqueous solution, unless the solvent is specified. A ''non-aqueous solution'' is a solution in which the solvent is a liquid, but is not water. (See also Solvent and Inorganic nonaqueous solvent.) Characteristics Substances that are ''hydrophobic'' ('water-fearing') do not dissolve well in water, whereas those that are ''hydrophilic'' ('water-friendly') do. An example of a hydrophilic substance is sodium chlo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
