912 resultados para Chemistry Ontology
Resumo:
Iron is one of the most common elements in the earth’s crust and thus its availability and economic viability far exceed that of metals commonly used in catalysis. Also the toxicity of iron is miniscule, compared to the likes of platinum and nickel, making it very desirable as a catalyst. Despite this, prior to the 21st century, the applicability of iron in catalysis was not thoroughly investigated, as it was considered to be inefficient and unselective in desired transformations. In this doctoral thesis, the application of iron catalysis in combination with organosilicon reagents for transformations of carbonyl compounds has been investigated together with insights into iron catalyzed chlorination of silanes and silanols. In the first part of the thesis, the synthetic application of iron(III)-catalyzed chlorination of silanes (Si-H) and the monochlorination of silanes (SiH2) using acetyl chloride as the chlorine source is described. The reactions proceed under ambient conditions, although some compounds need to be protected from excess moisture. In addition, the mechanism and kinetics of the chlorination reaction are briefly adressed. In the second part of this thesis a versatile methodology for transformation of carbonyl compounds into three different compound classes by changing the conditions and amounts of reagents is discussed. One pot reductive benzylation, reductive halogenation and reductive etherification of ketones and aldehydes using silanes as the reducing agent, halide source or cocatalyst, were investigated. Also the reaction kinetics and mechanism of the reductive halogenation of acetophenone are briefly discussed.
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Ontology matching is an important task when data from multiple data sources is integrated. Problems of ontology matching have been studied widely in the researchliterature and many different solutions and approaches have been proposed alsoin commercial software tools. In this survey, well-known approaches of ontologymatching, and its subtype schema matching, are reviewed and compared. The aimof this report is to summarize the knowledge about the state-of-the-art solutionsfrom the research literature, discuss how the methods work on different application domains, and analyze pros and cons of different open source and academic tools inthe commercial world.
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The thesis focuses on the water chemistry of the experimental test facilities and their reference VVER reactors. The main objective of the thesis is to provide recommendations for water chemistry management for laboratory facilities (VEERA, PACTEL) simulating the VVERs and for the large future facilities of the Lappeenranta University of Technology. In the beginning, the concept of nuclear power generation and the applicability of the nuclear power usage is discussed. Next, different water chemistry and water purification systems in primary and secondary circuits currently used at the power plant have been outlined. Also the construction geometry and design of test facilities PACTEL and VEERA, as well as the operation principles of their main equipment has been described. Finally, the appropriate water chemistry and water treatment system have been proposed for the existing and future experimental facilities of LUT.
Resumo:
Kandidaatintyö käsittelee ohjelmistojen markkinointia internetissä ja markkinoinnin mittaamista. Työssä esitellään internetin eri markkinointikanavat käsitellen niiden toteutustapoja, vahvuuksia ja heikkouksia sekä kustannuksia. Internet-markkinoinnin mittaamisesta käsitellään erilaisia tunnuslukuja sekä mittaamisen käyttökohteita. Työ on pääasiassa kirjallisuuskatsaus, mutta samalla myös case: työssä käsitellään Outotecin toimeksiannosta sen kehittämän HSC Chemistry -ohjelmiston markkinointia internetissä. Työn tuloksissa suositellaan HSC Chemistrylle sopivia markkinointikanavia ja niiden kustannuksia. Lisäksi arvioidaan käsiteltyjen mittaamistapojen soveltuvuutta ohjelmiston tapauksessa.
Resumo:
The text examines Sergej Nikolajeviè Bulgakov's description of the philosopheme as thoroughly "immanent" (viz., the immanence of man qua being, such that ontology in Bulgakov becomes a conceptual analogue for immanence) and the corollary that such immanence necessarily excludes the problematic of the "creation of the world." Because of this resolute immanence and the notion that the creation of the world in the form of creatio ex nihilo requires a non-immanent or non-ontological thought and concept, the problematic for Bulgakov is approached only by a theologeme. Appropriating this argument as material for a cursory philosopheme, the text attempts to transform Bulgakov's theologeme into a philosopheme through an elision of God and dogma that overdetermines the theologeme. This philosopheme (nascent within Bulgakov's work itself, in both his hesitation to the overdetermination of immanence and the commitment to the problem of creation) would be a thoroughly non-ontological philosopheme, one that allows for the treatment of the problematic of "creation" or singular ontogenesis, yet with the corollary that this philosopheme must rely on an "ontological zero" Such a philosopheme qua ontologically empty formula nevertheless remains ontologically significant insofar as it is to evince the limit of ontology, in the ontological zero's non-relationality to ontology.
Resumo:
Abstract: Nietzsche's Will-to-Power Ontology: An Interpretation of Beyond Good and Evil § 36 By: Mark Minuk Will-to-power is the central component of Nietzsche's philosophy, and passage 36 of Beyond Good and Evil is essential to coming to an understanding of it. 1 argue for and defend the thesis that will-to-power constitutes Nietzsche's ontology, and offer a new understanding of what that means. Nietzsche's ontology can be talked about as though it were a traditional substance ontology (i.e., a world made up of forces; a duality of conflicting forces described as 'towards which' and 'away from which'). However, 1 argue that what defines this ontology is an understanding of valuation as ontologically fundamental—^the basis of interpretation, and from which a substance ontology emerges. In the second chapter, I explain Nietzsche's ontology, as reflected in this passage, through a discussion of Heidegger's two ontological categories in Being and Time (readiness-to-hand, and present-at-hand). In a nutshell, it means that the world of our desires and passions (the most basic of which is for power) is ontologically more fundamental than the material world, or any other interpretation, which is to say, the material world emerges out of a world of our desires and passions. In the first chapter, I address the problematic form of the passage reflected in the first sentence. The passage is in a hypothetical style makes no claim to positive knowledge or truth, and, superficially, looks like Schopenhaurian position for the metaphysics of the will, which Nietzsche rejects. 1 argue that the hypothetical form of the passage is a matter of style, namely, the style of a free-spirit for whom the question of truth is reframed as a question of values. In the third and final chapter, 1 address the charge that Nietzsche's interpretation is a conscious anthropomorphic projection. 1 suggest that the charge rests on a distinction (between nature and man) that Nietzsche rejects. I also address the problem of the causality of the will for Nietzsche, by suggesting that an alternative, perspectival form of causality is possible.
Resumo:
Although it is generally accepted that Rydberg orbitals are very large and diffuse, and that electron promotion to a Rydberg orbital is not too different from ionization of the molecule, analysis of the two types of transitions proves otherwise. The photoelectron spectrum of the 2B2 (n) ion has very little vibrational structure attached to the origin band; on the other hand, several of the Rydberg transitions which involve the promotion of the n(bZ) electron exhibit a great deal of vibrational activity. In particular, the members of the n=3 Rydberg\ series interact with and perturb each other through pseudo-Jahn-Teller vibronic coupling. The vacuum ultraviolet spectrum contains a number of features which are difficult to explain, and two unusually sharp bands can only be identified as representing some form of electron promotion in formaldehyde.
Resumo:
The thermal decomposition of 2,3-di~ethy l - J-hydr operox y- 1 - butene , p r epared f rol") singl e t oxygen, has been studied i n three solvents over the tempe r a ture r ange from 1500e to l o00e and t!1e i 111 t ial ~oncentrfttl nn r Ange from O. 01 M to 0.2 M. Analys i s of the kine tic data ind ica te s i nduced homolysis as the n ost probRble mode of d e composition, g iving rise to a 3/2 f S order dependence upon hy d.roperoxide concent :r8.tl on . Experimental activation e nergies for the decomposition were f ound to be between 29.5 kcsl./raole and 30.0 k cal./mole .• \,iith log A factors between 11 . 3 and 12.3. Product studies were conducted in R variety of solvents a s well as in the pr esence of a variety of free r adical initiators . Investigation of the kinetic ch a in length indicated a chain length of about fifty. A degenerat i ve chain branching mechanism 1s proposed which predicts the multi t ude of products which Rre observed e xperimentally as well as giving activation energies and log A factors si~il a r to those found experimentally .
Resumo:
The one-electron reduced local energy function, t ~ , is introduced and has the property < tL)=(~>. It is suggested that the accuracy of SL reflects the local accuracy of an approximate wavefunction. We establish that <~~>~ <~2,> and present a bound formula, E~ , which is such that where Ew is Weinstein's lower bound formula to the ground state. The nature of the bound is not guaranteed but for sufficiently accurate wavefunctions it will yield a lower bound. ,-+ 1'S I I Applications to X LW Hz. and ne are presented.
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1-(0- and m-Ohlorobenzoyl)isoquinolines have been synthesized by two routes involving Reissert compounds. One route involves condensation of 2-benzoyl-l,2-dihydroisoquinaldonitrile with the appropriate chlorobenzaldehyde and the second involves rearrangement of the appropriate Z-(chlorobenzoyl)-l,Z-dihydroisoquinaldonitrile under basic conditions. The action of potassamide in anhydrous liquid ammonia on both ketones gave unexpectedly N-(l-isoquinolyl)benzamide (67) as the major product and the use of dibenzo-18-crown-6-ether 98% substantially improved the yd..e.ld in the case of l-chloroketone. This amide (67) exhibits unusual hydrogen bonding. 1-(o-chlorobenzoyl)-6,7-dimethoxyisoquinoline (79) was prepared in very s,amll quantities by the route involving condensation of 2-benzoyll, Z-dihydro-6,7-dimethoxyisoquinaldonitrile with o-chlorobenzaldehyde. The poor yields are due to the instability of the anion of 2-benzoyl1, Z-dihydro-6,7-dimethoxyisoquinaldonitrile. Attempted preparation of the ketone (79) by rearrangement of 2-(o-chlorobenzoyl)-l,2-dihydro6,7- dimethoxyisoquinaldonitrile under basic conditions yielded the start~ng material (Reissert compound) and 6,7-dimethoxyisoquinoline. The action of potassamide in anhydrous liquid ammonia on l-(o-bromo-4,5-dimethoxybenzoyl)isoquinoline (85), which was prepared by the route involving the condensation of 2-benzoyl-l,4-dihydroisoquinaldonitrile with o-bromo-4,5-dimethoxybenzaldehyde, gave two products, which have not yet been identified. The ketone (85) and its precursors are interest~ng in that their 20 eV and 70 eV mass spectra do not show molecular ions.
Resumo:
The work described in this thesis has been divided into seven sections. The first section involves the preparation of N'-acyl-N'-arylN- benzothiohydrazides by the acylation of N'-aryl-N-benzothiohydrazides and is followed by a brief discussion of their possible conformation in solution. The second section deals with the preparation of 1,3,4-thiadiazolium salts by the action of perchloric acid/acetic anhydride on N'-acylN'- aryl-N-benzothiohydrazides and also by the reaction of N'-arylN- benzothiohydrazides with nitriles in an acidic medium. The preparation of 2-methylthio-I,3,4-thiadiazolium methosulfate by methylating the corresponding thione is also described. The third section deals with the reaction of 2-phenyl- and 2-methyl-I,3,4-thiadiazolium salts with alcohols in the presence of base. The stability and spectra of these compounds are discussed. Treatment of the 2-methyl-I,3,4-thiadiazolium salt with base was found to give rise to a dimeric anhydrobase and evidence supporting its structure is given. The anhydrobase could be trapped by a variety of acylating and thioacylating agents before dimerization occurred. In the fourth section, the reaction of N'-acyl-N'-aryl-N-benzothiohydrazides with a variety of acid anhydrides is described. These compounds were found to be identical with those obtained by acylating the anhydrobase. The mass spectral fragmentation of these compounds is described and the anomolous product obtained upon thiobenzoylation of 3-methyl-l-phenyl-pyrazal-5-one is also discussed. The fifth section deals with thioacyl derivatives of the anhydrobase which were prepared by the action of phosphorus pentasulfide upon the oxygen analogues and also obtained as the major product of the reaction of thioacetic acid with compounds related to N'-aryl-N-benzothiohydrazides. The mass spectra and p.m.r. spectra of these compounds are discussed. In the sixth section, the reaction of the 2-methylthio-l,3,4- thiadiazolium salt with active methylene compounds to give acyl and diacyl derivatives of the anhydrobase is described. Some aspects of these compounds are discussed. The seventh section describes the synthesis of ncyanine~' type dyes incorporating the l,3,4-thiadiazole ring and their spectra are briefly discussed.
Resumo:
The work described in this thesis has been dtvided into six sections . The first section involves the reaction of 3,5-diphenyl-2-methyl-l,3,4-oxadiazolium perchlorate with acetic and benzoic anhydrides. The second section deals with the preparation and reactions of 1,3,4-thia diazolium salts. Some monomeric 1,3,4-thiadiazoline methine bases have also been prepared by reacting 1,3,4-thia d iaz ol ium s al t s with concen trated ammonium hydroxide solution. Variable temperature p.m.r. of 2-(3-acetylacetonylidene)-3,5-diphenyl-A4 -1,3,4-thiadiazoline has also been described. The third section deals with prepar a tion and reactions of some compounds in benzoxazole series. The fourth section deals with the prep a ration and reactions of N-alkyl-2-methylbenzothi azolium salts with base , a nd with some a cetylating and thioacetylating agents. Treatment of 2,3-dimethylbenzothiazolium iodide and of 3-ethyl-2-methylbenzothia zolium iodide with base wa s found to give the corresponding dimeric methine b a ses and evidence supporting their structure is also given. Thiol acetic acid was found to exchange 0 for S in its reactions with 2-acetonylidene-3-methylbenzothiazoline and 2-acetophenonylidene-3-methylbenzothi a zoline. (ii) In th e fifth section, the r eactions of 2,3-dimethylbenzselenazolium iodide with a variety of ac e tylating and thioacetylating agents has been described. The treatment of 2,3-dimethylbenzselenazolium iodide with base was found to give rise to a dimeric methine base and evidence supporting its structure is also given. The reactions of this dimeric methine b a se with benzoic anhydride and phenylisothiocyanate have also been described. The sixth section deals with the preparation and reactions of l-alkyl-2-methylquinolinium salts. Treatment of 1,2-dimethylquinolinium iodide and l-ethyl-2-methylquinolinium iodide was found to give the corresponding monomeric methine bases and evidence supporting their structure is also given. The E-type geometry of the olefinic bond in 2-acetonylidene-l-methylquinoline has been established on the basis of an N.O.E. experiment.
Resumo:
The x-ray crystal structure of thiamine hydroiodide,C1ZH18N40S12' has been determined. The unit cell parameters are a = 13.84 ± 0.03, o b = 7.44 ± 0.01, c = 20.24 ± 0.02 A, 8 = 120.52 ± 0.07°, space group P2/c, z = 4. A total of 1445 reflections having ,2 > 2o(F2), 26 < 40° were collected on a Picker four-circle diffractometer with MoKa radiation by the 26 scan technique. The structure was solved by the heavy atom method. The iodine and sulphur atoms were refined anisotropically; only the positional parameters were refined for the hydrogen atoms. Successive least squares cycles yielded an unweighted R factor of 0.054. The site of protonation of the pyrimidine ring is the nitrogen opposite the amino group. The overall structure conforms very closely to the structures of other related thiamine compounds. The bonding surrounding the iodine atoms is distorted tetrahedral. The iodine atoms make several contacts with surrounding atoms most of them at or near the van der Waal's distances A thiaminium tetrachlorocobaltate salt was produced whose molecular and crystal structure was j~dged to be isomorphous to thiaminium tetrachlorocadmate.
Resumo:
(A) Solid phase synthesis of oligonucleotides are well documented and are extensively studied as the demands continue to rise with the development of antisense, anti-gene, RNA interference, and aptamers. Although synthesis of RNA sequences faces many challenges, most notably the choice of the 2' -hydroxy protecting group, modified 2' -O-Cpep protected ribonucleotides were synthesized as alternitive building blocks. Altering phosphitylation procedures to incorporate 3' -N,N-diethyl phosphoramidites enhanced the overall reactivity, thus, increased the coupling efficiency without loss of integrety. Furthermore, technical optimizations of solid phase synthesis cycles were carried out to allow for successful synthesis of a homo UIO sequences with a stepwise coupling efficiency reaching 99% and a final yield of 91 %. (B) Over the past few decades, dipyrrometheneboron difluoride (BODIPY) has gained recognition as one of the most versatile fluorophores. Currently, BODIPY labeling of oligonucleotides are carried out post-synthetically and to date, there lacks a method that allows for direct incorporation of BODIPY into oligonucleotides during solid phase synthesis. Therefore, synthesis of BODIPY derived phosphoramidites will provide an alternative method in obtaining fluorescently labelled oligonucleotides. A method for the synthesis and incorporation of the BODIPY analogues into oligonucleotides by phosphoramidite chemistry-based solid phase DNA synthesis is reported here. Using this approach, BODIPY-labeled TlO homopolymer and ISIS 5132 were successfully synthesized.
Resumo:
At Brock University, the Faculty of Mathematics and Science currently has one of the highest percentages of students on academic probation, with many students reporting the most difficulty with Introductory Chemistry in first year and Organic Chemistry in second year. To identify strategies to improve students' performance and reduce the number of students on academic probation, a multi-year research project was undertaken involving several chemistry courses. Students were asked to complete three questionnaires, and provide consent to obtain their final Chemistry grade from the Registrar's Office. Research began at the end of the 2007-08 academic year with CHEM IPOO, and in the 2008-09 academic year, students in the larger CHEM IF92 Introductory Chemistry course were invited to participate in this research near the beginning of the academic year. Students who went on to take second year Organic and Analytical Chemistry were asked to complete these questionnaires in each second year course. The three questionnaires included the Kolb Learning Styles Inventory (Kolb, 1984) modified to include specific reference to Chemistry in each question, Dalgety, ColI, and Jones' (2002) Chemistry Attitudes and Experiences Questionnaire (CAEQ), and lastly, a demographic survey. Correlations were found between learning style and academic success; concrete learners were not as successful as abstract learners. Differences were noted between females and males with respect to learning styles, academic success, and confidence. Several differences were also noted between those who are the First in the Family to attend university and those who are not First in the Family to attend university.