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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Alkohol som socialt verktyg : Är alkoholhaltiga drycker nödvändiga för ett lyckat värdskap?

Edström, Anna, Löfgren, Samuel, Wictor, Jesper January 2013 (has links)
En lyckad social tillställning är beroende av gästernas humör. Värden har vissa verktyg hen kan ta till hjälp för att behålla en god atmosfär. I följande uppsats diskuterades möjligheterna alkoholen ger i jakten på ett framgångsrikt värdskap. Syftet med studien är att belysa alkohol som socialt verktyg vid mötet mellan värd och gäst med avseende att skapa ett lyckat värdskap. Uppsatsen är en litteraturstudie som har använt sig av fem vetenskapliga artiklar för besvara syftet. Resultatet som artiklarna visade var att alkohol i måttliga mängder gör människor mer sociala och avslappnade. Det framgick också att värdens uppgift är att uppfylla sina gästers önskemål och på så sätt värna om processen som utgör ett gott värdskap. Som en återbetalning för att du har blivit inbjuden har du som gäst en social skyldighet att bidra till gemenskapen. I Sverige har vår kultur och vetskapen om att alkohol är en normupplösare påverkat våra dryckesvanor. Svenskar är i många fall blyga och reserverade. Alkoholen har använts som ett verktyg för att lösa upp de sociala svårigheter som kan uppstå. Värden är oftast fullt medveten om det sistnämnda men den moraliska aspekten läggs åt sidan och fokusen ligger på att tillfredsställa gästen samt att upprätthålla god stämning. / B-uppsatser
2

Thiazole-containing natural and non-natural metal-complexing agents

Oldfield, Nigel Leigh January 2000 (has links)
No description available.
3

Functionalised calixarenes as chiral chromatographic selectors

Russell, Julie Alexandrea January 1997 (has links)
No description available.
4

Photochemical Reactions in a Water Soluble Supramolecular System: Influence of Confinement on Guest Reactivity and Product Selectivity

Parthasarathy, Anand 14 May 2009 (has links)
In this study, a synthetic, water soluble cavitand octa acid (OA) is used as medium for conducting photochemical reactions. The cavitand octa acid is soluble in water in slightly basic conditions. OA forms different types of complexes with variety of organic guest molecules. Remarkably, in presence of a hydrophobic guest, two of these OA molecules self assemble to form a capsular complex (guest@(OA)2). The confined inner phase of the cavitand can be utilized to control both photochemistry and photophysics of organic guest molecules. Stilbene derivatives undergo cis/trans (Z/E) photoisomerization in organic solvents. The results of our studies with stilbenes@(OA)2 suggest that the available free volume for encapsulated guest stilbenes could be manipulated by changing the number and position of the substituent methyl groups which has a significant influence on the photoisomerization process. Further, energy transfer from caged donor ((fluorenone)2@(OA)2) to caged acceptor ((stilbene)@(OA)2) was explored. It is also demonstrated that photoinduced electron transfer (PET) between acceptor (cationic) present outside the OA capsule to donor (a stilbene) present within the capsule is feasible and occurs at a higher than diffusion controlled rate. The PET in the above supramolecular system could be controlled by employing another cavitand, cucurbit[7]uril (CB7) to complex with cationic acceptor. Also, studies with carefully chosen guest molecules suggest that selective photocyclodimerization can be carried out within the inner phase of OA.
5

Platform Development for Characterization of Iron Catalysts Encapsulated in Metal-Organic Framework UiO-66:

Bensalah, Adam Tariq January 2020 (has links)
Thesis advisor: Jeffery A. Byers / Thesis advisor: Chia-Kuang Tsung / Host-guest chemistry provides a unique platform for catalysis by combining the specificity of homogeneous catalysts with the stability and recyclability of heterogeneous catalysts. Metal-Organic Frameworks (MOFs), such as UiO-66 are ideal hosts for host-guest catalysis. The vast porous network UiO-66 forms is chemically and thermally stable and the individual cages that make up the crystals can be modified by simple organic syntheses. The method developed in our group provides a mild, synthetically simple route for non-covalent organometallic guest encapsulation that decouples host synthesis from guest encapsulation. In this study, the so-called aperture opening encapsulation method is tested using an unstable class of iron-based carbon dioxide hydrogenation catalysts. The study results in launching an extensive investigation into the driving force behind aperture opening encapsulation with the goal of increasing guest loadings. Various methods to achieve this goal are explored including synthesizing novel UiO-66 linkers and taking advantage of factors such as columbic force. In conclusion, the information gained from a bigger picture examination of aperture opening encapsulation directly leads to guest loadings high enough to utilize useful characterization techniques. Accordingly, a standard protocol for characterization of iron catalysts encapsulated in UiO-66 is developed. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
6

Structural studies of supramolecular host-guest systems

2015 May 1900 (has links)
Abstract This research work details a systematic study of the structure and function of supramolecular host-guest systems. Host-guest inclusion complexes were formed between β-Cyclodextrin (β-CD) and its copolymers (as hosts), with several types of guest molecules both in aqueous solution and the solid state. The research is divided into two themes; (1) structural characterization and dynamic properties of the inclusion compounds of β-CD with various guest systems in aqueous solution and the solid phase, and (2) heterogeneous adsorption and structural studies of β-CD based copolymers with various guest systems in aqueous solutions. The guest systems include alkyl and perfluoroalkyl carboxylates, perfluoroalkyl sulfonate, and p-nitrophenol (PNP) at variable experimental conditions. In the first theme (chapter 2-5), host-guest complexes in the solid state were prepared using dissolution and slow cool methods at variable host/guest mole ratios (i.e., 1:1 and 2:1). The complexes were further characterized using 19F/13C DP/MAS and CP/MAS solid-state NMR spectroscopy. The solution state complexes were prepared in D2O for structural characterization using 1H/19F NMR spectroscopy. The NMR studies were complemented using FT-IR, thermal analyses (DSC, and TGA), and powder X-ray diffraction (PXRD). Evidence for the formation of host-guest inclusion compounds (ICs) was provided using CP/MAS solids NMR spectroscopy and complexation-induced chemical shift (CIS) values of 1H/19F nuclei in aqueous solution. The β-CD/PFC ICs displayed variable guest geometry and hydration states as determined by the host-guest stoichiometry and the conformation of the guest. PFOA and SPFO form 1:1 and 2:1 ICs with β-CD, wherein the guest adopts a range of gauche and trans conformations, respectively. 1:1 host-guest complexes were concluded for short perfluorocarbon chains (i.e., PFBA) where the gauche conformation of the PFC guest in the bound state was favoured. In the second theme (chapters 6–8), β-CD based copolymers were used as host materials. The structural characterization of a soluble poly-CD material (known as HDI-1) revealed that the solution behaviour of such polymeric hosts are sensitive to the presence of guest compounds such as p-nitrophenol (PNP) (i.e. chemo-responsive), as well as temperature variations (i.e. thermo-responsive). The host-guest chemistry of the soluble poly-CD material, as studied by 2-D solution NMR and induced circular dichroism (ICD) spectroscopy, indicates that PNP was bound within the cavity sites of β-CD and the interstitial domains of the copolymer (cf. Scheme 1.6 and chapter 6). The observed responsive nature of such polymeric host materials to temperature variation and chemical potential resembles behaviour characteristic of ‘smart materials’. Herein, ‘smart materials’ refer to systems which are responsive to external stimuli (e.g. temperature and chemical). The adsorption properties of the soluble (HDI-1) and insoluble (HDI-3 and -6) poly-CD adsorbents with octyl and perfluorooctyl carboxylate and sulfonate anions were estimated using the Sips and BET models. The hydrocarbon (HC) and fluorocarbon (FC) anions form monolayer and multilayer structures at the surface of the polymeric adsorbents, respectively. The formation of layered structures was controlled by the relative hydrophobicity of the alkyl/perfluoroalkyl chains and their mutual miscibility with the adsorbent surface. Other factors include the inductive effects of the alkyl/perfluoroalkyl head groups and their interactions with aqueous solvent or dipolar domains of the adsorbent surface. The adsorbed species at the liquid-solid interface were characterized using FT-IR spectroscopy, thermal analyses, and contact angle.
7

The study of optical characteristic by different alignment condition in the reflective Guest Host liquid crystal display

Chang, Yan-zhi 25 January 2008 (has links)
The Guest Host Mode of LCD is doped the dichroic dyes in liquid crystal and it have anisotropic absorbefacient. This operation mode can produce dark or brightness to achieve display target by the electric field and this can operate in the non-polarizer type to achieve high reflectance. Because of market requirement in the e-paper display, so the reflective LCD by the guest host mode is a focal once again. In this study, we will doped the black dichroic dyes in liquid crystal and than we fill into the homogenous alignment cell by difference rubbing direction and homeotropic alignment cell to investigate the optical-electric characteristic in the non-polarizer and polarizer type, because in the difference alignment condition can influence the behavior of dichroic dyes, and we fabricate the double cell to improve the optical-electric characteristic. The reflective type guest host display still have many research space, like dope the dichroic dye in PDLC(polymer dispread liquid crystals) or cholesteric liquid crystal to achieve flexible and bistable characteristic.
8

The synthesis of macrocyclic receptor compounds

Smith, Richard John Alan January 1986 (has links)
No description available.
9

New lower rim calix[4]arene derivatives containing mixed donor atoms, synthesis, characterisation and binding properties

Hutcherson, Robert George January 1997 (has links)
Novel P-tert-butylcalix[4]arene derivatives (L-3-10) containing mixed donor atoms (O, N, S) have been synthesised in a two stage reaction, the first part of which involves the preparation of L-2 using 18-crown-6 as a phase transfer catalyst and K2CO3 as a weak base. These conditions lead to the removal of two distal protons from the lower rim, allowing the 1,3-bis-niethylethylthio ether derivative (L-2) to be synthesised in a reduced reaction time with greater yield and purity than previously published. The final two protons were removed using NaH, sites to which a variety of amine, amide and thiophene moieties were introduced. This thesis reports investigations on these new compounds detailed as follows, i) 1H and 13C NMR characterisation of these derivatives. In two cases, X-ray crystallograpliic structures have been determined, showing distortions from the symmetrical cone conformation of p-tert-butylcalix[4]arene caused by steric interactions of the lower rim substituents. ii) Solubility and derived Gibbs energies of these ligands in various solvents at 298.15 K. Using acetonitrile and methanol as reference solvents, Gibbs energy of transfer are calculated. iii)The acid-base properties of ligands L-3,4,6-8 were investigated by potentiometry. Equilibrium constants for the dissociation processes reveal relative proton affinities in methanol at 298.15 K. Data of individual species present as a function of pH are presented in diagrams. iv) Conductimetric measurements. These data are used to derive the stoichiometry of metal cation complexes of L-4 in methanol. v) 1H NMR studies of the complexation of L-4 with metal cations in CD3OD at 298 K. These reveal conformational change in the macrocycle cyclic structure as the substituents' arrangements are altered to accommodate the guests cations. vi) Determination of Gibbs energy of complexation for ligand L-4 and Ag+, Pb+2, Cd2+ and Cu2+ metal cations in methanol at 298.15 K, using a competitive potentiometric method. Cation selectivities are discussed.
10

Our First Professor As A Guest!

Price-Rhea, Kelly 05 November 2018 (has links)
It's hard to imagine a simpler question: "Why Isn't Women's Golf More Popular?" That was the title of a recent article by Dr Kelly Price at the website www.womensgolf.com and while its a straightforward question the answers are anything but. Dr Price joins Episode 83 of the iSeekGolf podcast to chat about the complex world of gender politics and sport with a special focus on golf and it's a discussion you won't want to miss. Also, don't forget there is just under a week to go till our #ISGPod golf and live recording day. At the time of writing there is just one tee time left for next Monday at Bonnie Doon Golf Club so click here to register and pay. Alternatively, you can come along just for the recording where our special guest will be Mike Clayton who will take your questions on anything and everything to do with the game.

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