Système universitaire de documentation
The système universitaire de documentation or SUDOC is a system used by the libraries of French universities and higher education establishments to identify and manage the documents in their possession. The catalog, which contains more than 10 million references, allows students and researcher to search for bibliographical and location information in over 3,400 documentation centers, it is maintained by the Bibliographic Agency for Higher Education. Official website
National Library of Israel
The National Library of Israel Jewish National and University Library, is the library dedicated to collecting the cultural treasures of Israel and of Jewish heritage. The library holds more than 5 million books, is located on the Givat Ram campus of the Hebrew University of Jerusalem; the National Library owns the world's largest collections of Hebraica and Judaica, is the repository of many rare and unique manuscripts and artifacts. The B'nai Brith library, founded in Jerusalem in 1892, was the first public library in Palestine to serve the Jewish community; the library was located on B'nai Brith street, between the Meah Shearim neighborhood and the Russian Compound. Ten years the Bet Midrash Abrabanel library, as it was known, moved to Ethiopia Street. In 1920, when plans were drawn up for the Hebrew University, the B'nai Brith collection became the basis for a university library; the books were moved to Mount Scopus. In 1948, when access to the university campus on Mount Scopus was blocked, most of the books were moved to the university's temporary quarters in the Terra Sancta building in Rehavia.
By that time, the university collection included over one million books. For lack of space, some of the books were placed in storerooms around the city. In 1960, they were moved to the new JNUL building in Givat Ram. In the late 1970s, when the new university complex on Mount Scopus was inaugurated and the faculties of Law and Social Science returned there, departmental libraries opened on that campus and the number of visitors to the Givat Ram library dropped. In the 1990s, the building suffered from maintenance problems such as rainwater leaks and insect infestation. In 2007 the library was recognized as The National Library of the State of Israel after the passage of the National Library Law; the law, which came into effect on 23 July 2008, changed the library's name to "National Library of Israel" and turned it temporarily to a subsidiary company of the University to become a independent community interest company, jointly owned by the Government of Israel, the Hebrew University and other organizations.
In 2011, the library launched a website granting public access to books, maps and music from its collections. In 2014, the project for a new home of the Library in Jerusalem was unveiled; the 34,000 square meters building, designed by the Swiss architecture firm Herzog & de Meuron, is scheduled for full completion in 2021. The library's mission is to secure copies of all material published in any language. By law, two copies of all printed matter published in Israel must be deposited in the National Library. In 2001, the law was amended to include audio and video recordings, other non-print media. Many manuscripts, including some of the library's unique volumes such the 13th century Worms Mahzor, have been scanned and are now available on the Internet. Among the library's special collections are the personal papers of hundreds of outstanding Jewish figures, the National Sound Archives, the Laor Map Collection and numerous other collections of Hebraica and Judaica; the library possesses some of Isaac Newton's manuscripts dealing with theological subjects.
The collection, donated by the family of the collector Abraham Yahuda, includes a large number of works by Newton about mysticism, analyses of holy books, predictions about the end of days and the appearance of the ancient Temple in Jerusalem. It contains maps that Newton sketched about mythical events to assist him in his end of days calculations; the library houses the personal archives of Gershom Scholem. Following the occupation of West Jerusalem by Haganah forces in May 1948, the libraries of a number Palestinians who fled the country as well as of other well-to-do Palestinians were transferred to the National Library; these collections included those of Henry Cattan, Khalil Beidas, Khalil al-Sakakini and Aref Hikmet Nashashibi. About 30,000 books were removed from homes in West Jerusalem, with another 40,000 taken from other cities in Mandatory Palestine, it is unclear whether the books were being kept and protected or if they were looted from the abandoned houses of their owners. About 6,000 of these books are in the library today indexed with the label AP – "Abandoned Property".
The books are cataloged, can be viewed from the Library's general catalog and are consulted by the public, including Arab scholars from all over the world. List of national and state libraries Union List of Israel Judaica Archival Project Official website
Friedrich August Kekulé Friedrich August Kekule von Stradonitz, was a German organic chemist. From the 1850s until his death, Kekulé was one of the most prominent chemists in Europe in theoretical chemistry, he was the principal founder of the theory of chemical structure. Kekulé never used his first given name. After he was ennobled by the Kaiser in 1895, he adopted the name August Kekule von Stradonitz, without the French acute accent over the second "e"; the French accent had been added to the name by Kekulé's father during the Napoleonic occupation of Hesse by France, to ensure that French-speaking people pronounced the third syllable. The son of a civil servant, Kekulé was born in the capital of the Grand Duchy of Hesse. After graduating from secondary school, in the fall of 1847 he entered the University of Giessen, with the intention of studying architecture. After hearing the lectures of Justus von Liebig in his first semester, he decided to study chemistry. Following four years of study in Giessen and a brief compulsory military service, he took temporary assistantships in Paris, in Chur, in London, where he was decisively influenced by Alexander Williamson.
His Giessen doctoral degree was awarded in the summer of 1852. In 1856 Kekulé became Privatdozent at the University of Heidelberg. In 1858 he was hired as full professor at the University of Ghent in 1867 he was called to Bonn, where he remained for the rest of his career. Basing his ideas on those of predecessors such as Williamson, Edward Frankland, William Odling, Auguste Laurent, Charles-Adolphe Wurtz and others, Kekulé was the principal formulator of the theory of chemical structure; this theory proceeds from the idea of atomic valence the tetravalence of carbon and the ability of carbon atoms to link to each other, to the determination of the bonding order of all of the atoms in a molecule. Archibald Scott Couper independently arrived at the idea of self-linking of carbon atoms, provided the first molecular formulas where lines symbolize bonds connecting the atoms. For organic chemists, the theory of structure provided dramatic new clarity of understanding, a reliable guide to both analytic and synthetic work.
As a consequence, the field of organic chemistry developed explosively from this point. Among those who were most active in pursuing early structural investigations were, in addition to Kekulé and Couper, Wurtz, Alexander Crum Brown, Emil Erlenmeyer, Alexander Butlerov. Kekulé's idea of assigning certain atoms to certain positions within the molecule, schematically connecting them using what he called their "Verwandtschaftseinheiten", was based on evidence from chemical reactions, rather than on instrumental methods that could peer directly into the molecule, such as X-ray crystallography; such physical methods of structural determination had not yet been developed, so chemists of Kekulé's day had to rely entirely on so-called "wet" chemistry. Some chemists, notably Hermann Kolbe criticized the use of structural formulas that were offered, as he thought, without proof. However, most chemists followed Kekulé's lead in pursuing and developing what some have called "classical" structure theory, modified after the discovery of electrons and the development of quantum mechanics.
The idea that the number of valences of a given element was invariant was a key component of Kekulé's version of structural chemistry. This generalization suffered from many exceptions, was subsequently replaced by the suggestion that valences were fixed at certain oxidation states. For example, periodic acid according to Kekuléan structure theory could be represented by the chain structure I-O-O-O-O-H. By contrast, the modern structure of periodic acid has all four oxygen atoms surrounding the iodine in a tetrahedral geometry. Kekulé's most famous work was on the structure of benzene. In 1865 Kekulé published a paper in French suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds; the following year he published a much longer paper in German on the same subject. The empirical formula for benzene had been long known, but its unsaturated structure was a challenge to determine. Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but the study of aromatic compounds was in its earliest years, too little evidence was available to help chemists decide on any particular structure.
More evidence was available by 1865 regarding the relationships of aromatic isomers. Kekulé argued for his proposed structure by considering the number of isomers observed for derivatives of benzene. For every monoderivative of benzene only one isomer was found, implying that all six carbons are equivalent, so that substitution on any carbon gives only a single possible product. For diderivatives such as the toluidines, C6H4, three isomers were observed, for which Kekulé proposed structures with the two substituted carbon atoms separated by one and three carbon-carbon bonds named ortho and para isomers respectively; the counting of possible isomers for diderivatives was however criticized by Albert Ladenburg, a for
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
Phenol is an aromatic organic compound with the molecular formula C6H5OH. It is a white crystalline solid, volatile; the molecule consists of a phenyl group bonded to a hydroxy group. It requires careful handling due to its propensity for causing chemical burns. Phenol was first extracted from coal tar, it is an important industrial commodity as a precursor to useful compounds. It is used to synthesize plastics and related materials. Phenol and its chemical derivatives are essential for production of polycarbonates, Bakelite, detergents, herbicides such as phenoxy herbicides, numerous pharmaceutical drugs. Phenol is an organic compound appreciably soluble in water, with about 84.2 g dissolving in 1000 mL. Homogeneous mixtures of phenol and water at phenol to water mass ratios of ~2.6 and higher are possible. The sodium salt of phenol, sodium phenoxide, is far more water-soluble. Phenol is weakly acidic and at high pHs gives the phenolate anion C6H5O−: PhOH ⇌ PhO− + H+ Compared to aliphatic alcohols, phenol is about 1 million times more acidic, although it is still considered a weak acid.
It reacts with aqueous NaOH to lose H+, giving the salt sodium phenoxide, whereas most alcohols react only partially. One explanation for the increased acidity over alcohols is resonance stabilization of the phenoxide anion by the aromatic ring. In this way, the negative charge on oxygen is delocalized on to the ortho and para carbon atoms through the pi system. An alternative explanation involves the sigma framework, postulating that the dominant effect is the induction from the more electronegative sp2 hybridised carbons. In support of the second explanation, the pKa of the enol of acetone in water is 10.9, making it only less acidic than phenol. Thus, the greater number of resonance structures available to phenoxide compared to acetone enolate seems to contribute little to its stabilization. However, the situation changes. A recent in silico comparison of the gas phase acidities of the vinylogues of phenol and cyclohexanol in conformations that allow for or exclude resonance stabilization leads to the inference that about 1⁄3 of the increased acidity of phenol is attributable to inductive effects, with resonance accounting for the remaining difference.
The phenoxide anion has a similar nucleophilicity to free amines, with the further advantage that its conjugate acid does not become deactivated as a nucleophile in moderately acidic conditions. Phenolate esters are more stable toward hydrolysis than acid anhydrides and acyl halides but are sufficiently reactive under mild conditions to facilitate the formation of amide bonds. Phenol exhibits keto-enol tautomerism with its unstable keto tautomer cyclohexadienone, but only a tiny fraction of phenol exists as the keto form; the equilibrium constant for enolisation is 10−13, which means only one in every ten trillion molecules is in the keto form at any moment. The small amount of stabilisation gained by exchanging a C=C bond for a C=O bond is more than offset by the large destabilisation resulting from the loss of aromaticity. Phenol therefore exists entirely in the enol form. Phenoxides are enolates stabilised by aromaticity. Under normal circumstances, phenoxide is more reactive at the oxygen position, but the oxygen position is a "hard" nucleophile whereas the alpha-carbon positions tend to be "soft".
Phenol is reactive toward electrophilic aromatic substitution as the oxygen atom's pi electrons donate electron density into the ring. By this general approach, many groups can be appended to the ring, via halogenation, acylation and other processes. However, phenol's ring is so activated—second only to aniline—that bromination or chlorination of phenol leads to substitution on all carbon atoms ortho and para to the hydroxy group, not only on one carbon. Phenol reacts with dilute nitric acid at room temperature to give a mixture of 2-nitrophenol and 4-nitrophenol while with concentrated nitric acid, more nitro groups get substituted on the ring to give 2,4,6-trinitrophenol, known as picric acid. Aqueous solutions of phenol are weakly acidic and turn blue litmus to red. Phenol is neutralized by sodium hydroxide forming sodium phenate or phenolate, but being weaker than carbonic acid, it cannot be neutralized by sodium bicarbonate or sodium carbonate to liberate carbon dioxide. C6H5OH + NaOH → C6H5ONa + H2OWhen a mixture of phenol and benzoyl chloride are shaken in presence of dilute sodium hydroxide solution, phenyl benzoate is formed.
This is an example of the Schotten-Baumann reaction: C6H5OH + C6H5COCl → C6H5OCOC6H5 + HClPhenol is reduced to benzene when it is distilled with zinc dust, or when phenol vapour is passed over granules of zinc at 400 °C: C6H5OH + Zn → C6H6 + ZnOWhen phenol is reacted with diazomethane in the presence of boron trifluoride, anisole is obtained as the main product and nitrogen gas as a byproduct. C6H5OH + CH2N2 → C6H5OCH3 + N2When phenol reacts with iron chloride solution, an intense violet-purple solution is formed; because of phenol's commercial importance, many methods have been developed for its production. The dominant current route, accounting for 95% of production, is the cumene process, which uses benzene and propene as feedstock and involves the partial oxidation of cumene vi
Chemistry is the scientific discipline involved with elements and compounds composed of atoms and ions: their composition, properties and the changes they undergo during a reaction with other substances. In the scope of its subject, chemistry occupies an intermediate position between physics and biology, it is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant chemistry, the formation of igneous rocks, how atmospheric ozone is formed and how environmental pollutants are degraded, the properties of the soil on the moon, how medications work, how to collect DNA evidence at a crime scene. Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. There are four types of chemical bonds: covalent bonds, in which compounds share one or more electron; the word chemistry comes from alchemy, which referred to an earlier set of practices that encompassed elements of chemistry, philosophy, astronomy and medicine.
It is seen as linked to the quest to turn lead or another common starting material into gold, though in ancient times the study encompassed many of the questions of modern chemistry being defined as the study of the composition of waters, growth, disembodying, drawing the spirits from bodies and bonding the spirits within bodies by the early 4th century Greek-Egyptian alchemist Zosimos. An alchemist was called a'chemist' in popular speech, the suffix "-ry" was added to this to describe the art of the chemist as "chemistry"; the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία; this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, in turn derived from the word Kemet, the ancient name of Egypt in the Egyptian language. Alternately, al-kīmīā may derive from χημεία, meaning "cast together"; the current model of atomic structure is the quantum mechanical model. Traditional chemistry starts with the study of elementary particles, molecules, metals and other aggregates of matter.
This matter can be studied in isolation or in combination. The interactions and transformations that are studied in chemistry are the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together; such behaviors are studied in a chemistry laboratory. The chemistry laboratory stereotypically uses various forms of laboratory glassware; however glassware is not central to chemistry, a great deal of experimental chemistry is done without it. A chemical reaction is a transformation of some substances into one or more different substances; the basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which involves atoms as subjects; the number of atoms on the left and the right in the equation for a chemical transformation is equal. The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.
Energy and entropy considerations are invariably important in all chemical studies. Chemical substances are classified in terms of their structure, phase, as well as their chemical compositions, they can be analyzed using the tools of e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines. Several concepts are essential for the study of chemistry; the particles that make up matter have rest mass as well – not all particles have rest mass, such as the photon. Matter can be a mixture of substances; the atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud; the nucleus is made up of positively charged protons and uncharged neutrons, while the electron cloud consists of negatively charged electrons which orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons.
The nucleus is dense. The atom is the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state, coordination number, preferred types of bonds to form. A chemical element is a pure substance, composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z; the mass number is the sum of the number of neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same
Charles Frédéric Gerhardt
Charles Frédéric Gerhardt was a French chemist. He was born in Paris, where he attended the gymnasium, he studied at the Karlsruhe Institute of Technology, where Friedrich Walchner's lectures first stimulated his interest in chemistry. Next he attended the school of commerce in Leipzig, where he studied chemistry under Otto Linné Erdmann, who further developed his interest into a passion for questions of speculative chemistry. Returning home in 1834, he entered his father’s white lead factory, but soon found that business was not to his liking, after a sharp disagreement with his father in his 20th year he enlisted in a cavalry regiment. In a few months military life became distasteful, he purchased his discharge with the assistance of the German chemist Justus von Liebig. After a short period of living in Dresden, he went to the University of Giessen in central Germany in 1836 to study and work in Liebig's laboratory, his stay at Giessen lasted 18 months, in 1837 he re-entered the factory. Again, however, he quarrelled with his father, in 1838 he went to Paris with introductions from Liebig.
In Paris, he attended Jean Baptiste Dumas’ lectures and worked with Auguste Cahours on essential oils cumin, in Michel Eugène Chevreul’s laboratory at the Jardin des Plantes, meanwhile earning a precarious living by teaching and making translations of some of Liebig’s writings. In 1841, through the influence of Dumas, he was charged with the duties of chemistry professor at the Montpellier faculty of sciences, becoming titular professor in 1844. In 1842 he annoyed his friends in Paris by the matter and manner of a paper on the classification of organic compounds, he published Précis de chimie organique. In 1845 he and his opinions were the subject of an attack by Liebig, unjustifiable in its personalities but not altogether surprising in view of his wayward disregard of his patron’s advice; the two were reconciled in 1850, but his faculty for disagreeing with his friends did not make it easier for him to get another appointment after resigning the chair at Montpellier in 1851 as he was unwilling to go into the provinces.
He obtained leave of absence from Montpellier in 1848 so that he could pursue without interruption his special investigations, from that year until 1855 he resided in Paris. During that period he established an École de chimie pratique. However, these hopes were disappointed, in 1855, after refusing the offer of a chair of chemistry at the new Zürich Polytechnic in 1854, he accepted the professorships of chemistry at the Faculty of Sciences and the École Polytechnique at Strassburg, where he died the following year, having just completed checking the proofs for Traité de chimie organique, his magnum opus; this latter work embodies all his discoveries. Gerhardt is known for his work on reforming the notation for chemical formulas, he worked on acid anhydrides, synthesized acetylsalicylic acid, albeit in an unstable and impure form. Gerhardt is linked with his contemporary, Auguste Laurent, with whom he shared a strong and influential interest in chemical combination, he died on August 19, 1856, two days short of his birthday, after being poisoned by his own chemicals during laboratory work.
He was 39 years old. Gilman, D. C.. "Gerhardt, Karl Friedrich". New International Encyclopedia. New York: Dodd, Mead. Charlot, Colette. "". Revue d'histoire de la pharmacie. 55: 197–208. Doi:10.3406/pharm.2007.6333. PMID 18175527. Viel, Claude. "". Revue d'histoire de la pharmacie. 55: 189–96. PMID 18175526. Lafont, O. "". Revue d'histoire de la pharmacie. 43: 269–73. PMID 11624864. Dickerson, Jimmy. "Charles Gerhardt and the Theory of Organic Combination". Journal of Chemical Education. 62: 323–325. Bibcode:1985JChEd..62..323D. Doi:10.1021/ed062p323. Grimaux. M.. C.. Charles Gerhardt, sa Vie, son Oeuvre, sa Correspondance. Paris: Masson. Moore, F. J.. A History of Chemistry. New York: McGraw-Hill.- See Chapter 6, "Gerhardt and the Chemical Reformation - Williamson". Attribution This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed.. "Gerhardt, Charles Frédéric". Encyclopædia Britannica. Cambridge University Press. Tiffeneau, Marc. "". Moniteur scientifique. 7: 5–42. Tiffeneau, Marc. Correspondance de Charles Gerhardt, Tome 1, Auguste Laurent et Charles Gerhardt.
Paris: Masson & Cie. CS1 maint: Extra text: authors list Tiffeneau, Marc. "Wurtz". Revue scientifique. 59: 576–584. Tiffeneau, Marc. Correspondance de Charles Gerhardt, Tome 2, Gerhardt et les savants français. Paris: Masson & Cie. CS1 maint: Extra text: authors list "Gerhardt, Karl Friedrich". Encyclopedia Americana. 1920