982 resultados para Ernest R. Graham
Resumo:
Dimerization of thiolbenzoic acid has been studied by infra-red, ultra-violet and n.m.r. spectroscopy and cryoscopy. The results indicate that the tendency to form S - H. O hydrogen bonds is not appreciable.
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An analysis of eccentrically loaded short reinforced concrete columns using a variable failure strain criterion is presented. The method dispenses with the usual procedure of assuming a fixed value for the ultimate strain in concrete. The analysis is based on the use of a simple, single equation for the complete stress-strain curve of concrete and the adoption of a process of maximisation of moment with respect to extreme fibre concrete compressive strain. Columns of rectangular section and loaded eccentrically along one axis only are considered in this paper. A good agreement is observed between the theoretical and experimental values of some test results.
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Stress-strain characteristics of concrete confined in steel binders have been determined. A new factor “confinement index” has been introduced for a quantitative measure of the confinement and using these results a “stress-block” has been developed. Tests have been made on simply supported reinforced concrete beams with spiral binder confinement and analysed on the basis of the proposed stress-block. Tests have also been made oon reinforced concrete portal frames and continuous beams with spiral binder confinement at sections of possible plastic hinge formation. An analysis of these tests indicates that a full redistribution of moments has taken place at ultimate.
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A method is presented for obtaining lower bound on the carrying capacity of reinforced concrete foundation slab-structures subject to non-uniform contact pressure distributions. Functional approach suggested by Vallance for simply supported square slabs subject to uniform pressure distribution has been extended to simply supported rectangular slabs subject to symmetrical non-uniform pressure distributions. Radial solutions, ideally suited for rotationally symmetric problems, are shown to be adoptable for regular polygonal slabs subject to contact pressure paraboloids with constant edge pressures. The functional approach has been shown to be well suited even when the pressure is varying along the edges.
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The r.f. absorption experiment performed on YBa2Cu3O7-x ceramic pellets using a CW NMR spectrometer shows some novel observed in the microwave range.
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Det är helt naturligt att konsumenterna sprider marknadsinformation genom att sinsemellan prata om sina konsumtionserfarenheter. Även om man i marknadsföringslitteraturen betonar den konsumentdominerade informella marknadskommunikationens genuina karaktär jämfört med den företagsdominerade formella marknadskommunikationen, så har man rtt dåliga kunskaper om företagets möjligheter att systematiskt utnyttja denna typ av marknadskommunikation. Min analys tyder på att den beteendevetenskapliga och den företagsekonomiska word-of-mouth-forskningen anlägger olika perspektiv som inte möter varandra. Den beteendevetenskapliga word-of-mouth-forskningen har tydligare satt fokus på själva företeelsen informell marknadskommunikation, men perspektivet har inte varit speciellt företagsorienterat. Den företagsekonomiska word-of-mouth-forskningen har i sin tur varit betydligt tydligare fokuserad på möjligheterna att använda informell marknadskommunikation, men däremot har man inte fäst speciellt mycket uppmärksamhet vid själva företeelsen informell marknadskommunikation. Min kontribution till den vetenskapliga diskussionen om företagens möjligheter att systematisera utnyttjandet av informell marknadskommunikation består i att överbrygga denna dualism inom word-of-mouth-forskningen genom att anlägga ett företagsperspektiv på den sociala dynamiken för informell marknadskommunikation. Denna ansats har sin teoretiska förankring hos de s.k. moderna men bortglömda pionjärerna, med vilka jag avser Johan Arndt, Donald Cox och Ernest Dichters kontribution till den företagsorienterade word-of-mouth-forskningen redan i slutet av 1960-talet. Efter det har deras synpunkter och insikter varken förts vidare eller vidareutvecklats, vilket jag betraktar som ett bakslag för den företagsorienterade word-of-mouth-forskningen. Föreliggande studie har bidragit till word-of-mouth-forskningen på tre olika sätt: genom 1) bidrag baserat på litteraturanalys, 2) bidrag baserat på empirianalys och 3) bidrag baserat på begreppsligande av informell marknadskommunikation. Min litteraturanalys framställer word-of-mouth-forskningens uppkomst och utveckling i ny dager. Min empirianalys har genererat empiriska begrepp, dels för att beskriva informell marknadskommunikation som företeelse, dels för att beskriva företagens förfarande för att systematisera utnyttjandet av sådan marknadskommunikation. Den begreppsliga kontributionen accentueras i informell marknadskommunikation som ett samlingsbegrepp för olika typer av interkonsumentkommunikation.
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Mononuclear, binuclear and trinuclear silver(l) complexes were obtained unexpectedly while probing the reactivity of diphosphazane ligands of the type X2PN(Pr-i)PXY towards the ruthenium-based precursor Ru(bipy)(2)Cl-2 center dot 2H(2)O, in the presence of a silver salt as a chloride scavenger. Subsequently, the reactions of AgX [X = Cl, NO3 or CF3SO3] with Ph2PN(R)PPh(Y) [R = H, Y = Ph; R = Pr-i, Y = Ph or OC6H3Me2-2,6] in a 1: 1 or 1:2 molar ratio have been investigated. Mononuclear or binuclear Ag(I) complexes containing either chelating or bridging diphosphazane ligands are obtained. Trinuclear silver(l) complexes are accessible by the treatment of diphosphazane ligands, Ph2PN(R)PPh2 [R = H, Pr-i] with AgCl using piperidine as the solvent. In the presence of a suitable chloride donor species, the mononuclear and binuclear complexes of Ph2PN(Pr-i)PPh2 are transformed slowly to the trinuclear complex [Ag-3(mu-Cl)(2){Ph2PN(Pr-i)PPh2}(3)]X, over a period 20 h. The structures of representative complexes have been confirmed by X-ray crystallography and the salient structural features are discussed
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We construct an invariant of certain open four-manifolds using the Heegaard Floer theory of Ozsvath and Szabo. We show that there is a manifold X homeomorphic to R-4 for which the invariant is non-trivial,showing that X is an exotic R-4. This is the first invariant that detects exotic R-4' s. (C) 2009 Published by Elsevier GmbH.
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The first enantiospecific synthesis of a thapsane, containing three contiguous quaternary carbon atoms, is accomplished starting from R-carvone. An intramolecular alkylation and an intramolecular diazoketone cyclopropanation reaction were employed for the stereo- and regiospecific generation of three contiguous quaternary carbon atoms present in the thapsane framework.
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1S,5R,7R)-(-)-10, 10-Dimethyl-3-ethyl-4-oxa--atricyclo[5.2.1.0(1,5)]dec-2-ene 2 was prepared in 95% yield from (1S)-1-amino-2-exo-hydroxyapocamphane 1. The chiral oxazoline could be alkylated (Lhttp://eprints.iisc.ernet.in/cgi/users/home?screen=EPrint::Edit&eprintid=31175&stage=core#tDA/THF/-78 degrees C/RX, RX = ethyl, n-propyl, n-butyl iodides or benzyl bromide) to 3 in 95% yield and > 95% diastereoselectivity, and the products hydrolysed to (R)-2-methylalkanoic acids 4 (43-47% yield, 93-98% e.e.). (C) 2000 Elsevier Science Ltd. All rights reserved.
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A simple and direct approach to both enantiomeric series of A-ring derivatives of 1 alpha,25-dihydroxyvitamin D-3 and the corresponding 1 alpha,3 alpha-derivatives, starting from the abundantly available R-carvone, is described. (C) 2000 Elsevier Science Ltd. All rights reserved.