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The development of analytical techniques for studying degradation in impact polypropylene copolymersDe Goede, Elana 03 1900 (has links)
Thesis (DSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009. / Unstabilised polyolefins are susceptible to degradation when exposed to molecular oxygen, heat, irradiation as well as chemical and mechanical stimuli. Oxidation leads to changes in molecular properties such as molecular weight, molecular weight distribution, chemical composition, chemical composition distribution and crystallisability. Conventional analytical techniques are of limited use when studying the degradation of heterogeneous materials such as impact polypropylene copolymers (ICPP). These copolymers consist of a number of components of different monomer contents, isotacticity and crystallinity, ranging from amorphous EPR to highly crystalline polypropylene. The individual components are affected differently by degradation, leading to heterogeneity within the degradation of impact copolymers. Novel analytical approaches that acknowledge the heterogeneity in sample composition are needed to study the degradation behaviour of such heterogeneous materials.
This study describes the combination of fractionation and hyphenated techniques with conventional analyses for extensive structural characterisation of complex impact copolymers as well as their degradation behaviour. Temperature rising elution fractionation (TREF) coupled to conventional techniques such as size exclusion chromatography (SEC), Fourier-Transform infrared spectroscopy (FTIR), Carbon-13 nuclear magnetic resonance (13C-NMR) and differential scanning calorimetry (DSC) indicated the ICPPs in question to consist of four main components, namely ethylene-propylene random copolymers (EPR), isotactic PP (iPP), as well as semi-crystalline ethylene-propylene copolymers (EPC) and lower isotacticity PP. The degradation of an ICPP was studied by a multi-component analysis procedure consisting of TREF coupled to SEC, 13C-NMR, as well as SEC-FTIR. Results obtained by this procedure indicated the change in crystallisability of the bulk sample observed by TREF, crystallisation analysis fractionation (CRYSTAF) and DSC to be the result of the preferential degradation of the iPP phase. Degradation of ICPPs initiates within this phase where chain scission and carbonyl group insertion leads to a change in the crystallisability of iPP chains. During TREF of degraded bulk ICPPs, the degraded iPP molecules elute at lower elution temperatures, depending on their degree of degradation. The other components of the copolymer were degraded to a lesser extent. Degradation products were also found to be heterogeneously distributed across the molecular weight distribution of each fraction, with a higher concentration appearing at the low molecular weight side. The multi-component analysis procedure was also used to study the difference in degradation behaviour between ICPPs of different comonomer content, isotacticity and crystallinity.
The spatial heterogeneity of degradation within ICPPs was studied by Fourier-Transform infrared microspectroscopy (FTIR-μS). A heterogeneous distribution of degradation products was found across the depth of thicker sample specimens. These results were compared to those obtained by conventional layer-by-layer milling followed by SEC, FTIR and CRYSTAF. The principles of degradation within thick samples were similar to that observed for thin films, although additional contributions by sample morphology and oxygen diffusion were detected.
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Mass Tourism and the Environment : A Translation Study of Terminology, Metaphors and Hyphenated Premodifiers in Two ArticlesLindblad, Cecilia January 2010 (has links)
<p>The following essay is an analysis of a translation from English into Swedish of two articles concerning tourism, travelling and the environment. The language of the articles is expressive and rich in metaphors, which evokes images in the mind of the reader. The translation was performed with the aim to transfer this effect into the translated texts and the aspects to be examined in the analysis were chosen with this in mind.One of the three aspects to be examined is the use of metaphors and how they are translated into Swedish. Many of the metaphors bear reference to travelling and the environment which gives them a function of enforcing the message and engaging the reader in the text. In order to obtain the same effect in the Swedish translations several translation strategies had to be used.The second aspect to be examined is the terminology used within tourism and the environment. The environmental concern is a growing trend which inevitably influences the language and requires a new set of useful and understandable terms. This becomes clear when reading and translating the articles at hand. The environmental terms are fairly new and sometimes hard to distinguish. In this study focus is set on the translation strategies and the procedures used in order to find the Swedish equivalents of the terms in this context.The third aspect is the translation of hyphenated pre-modifiers. This aspect is particularly interesting, since the phenomenon is more or less unknown in Swedish. Of the fifteen hyphenated pre-modifiers in the source texts none were translated into hyphenated pre-modifiers in Swedish although five of them were translated into regular pre-modifiers. The analysis is based on the translation strategies applied and the comparison of syntactic structures of the expressions in English and Swedish.</p>
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Estudos das variações sazonais e intrapopulacional dos metabólitos secundários majoritários das folhas de \'Eremanthus glomerulatus Less\' (Asteraceae) / Study of the seasonal and intrapopulational variations of the secondary metabolites from the leaves of Eremanthus glomerulatus Less (Asteraceae).Amaral, Juliano Geraldo 22 February 2008 (has links)
O trabalho buscou investigar as variações sazonais de metabólitos secundários em Eremanthus glomerulatus Less (Asteraceae). Embora não ser utilizada para fins medicinais esta espécie contem substâncias biologicamente ativas. Para este estudo, foram selecionados dez indivíduos de uma mesma população localizada na região do município de Ibiraci - MG, que durante um período de aproximadamente dois anos (06/2000 a 04/2002) tiveram um de seus ramos coletados mensalmente. Visando a análise das folhas destes ramos uma metodologia para extração e análise de seus metabólitos secundários majoritários por CLAE-UV foi desenvolvida e utilizada para determinação de suas variações sazonais. A identificação destes metabólitos se deu principalmente pelas técnicas hifenadas CLAE-DAD-EM e CLAE-DAD-EM/EM. Os metabólitos que não puderam ser identificados por estas ferramentas foram isolados do extrato etanólico foliar desta espécie e identificados por RMN de 1H e 13C e EM. Durante este estudo foi verificado que o envelhecimento das folhas resulta em uma significativa redução no conteúdo de todos os seus metabólitos secundários. Também foi possível identificar nove metabólitos secundários pertencentes as classes dos ácidos cafeoilquínicos, derivados fenólicos e flavonóides, dos quais foram isolados três, sendo dois ainda não relatados na literatura. Quanto a variação sazonal pode-se verificar que os indivíduos apresentam perfis metabólicos bem semelhante com diferenças quantitativas mas praticamente não apresentando variações qualitativas entre os indivíduos. Pode-se observar também que há um metabolismo bem diversificado no qual nem sempre todos os indivíduos apresentam aumento de produção de um mesmo metabólito em determinada estação do ano. Apesar das variáveis é possível definir o outono e a primavera como as estações que durante o estudo apresentaram os melhores índices de produção de praticamente todos os metabólitos analisados. Por fim pode-se concluir que as variações sazonais em E. glomerutalus são significativas e que são determinantes para definir a época de futuras coletas para posteriores estudos químicos ou farmacológicos. / This study was performed to investigate the seasonal intrapopulational variations of the secondary metabolites in Eremanthus glomerulatus Less (Asteraceae). Although this species is not used for medicinal purposes, it contains biologically active substances. For this study, ten individuals from the same population located in the region of Ibirici city, Minas Gerais state, had one of their lbranches collected monthly for about two years (from 06/2000 to 04/2002). Aiming the analysis of the leaves from the branches, a methodology on UV-HPLC was developed and used for the extraction and analysis of major secondary metabolites to determine the seasonal variations. The identification of the metabolites has occurred mainly by the HPLC-DAD-MS and HPLC-DAD-MS/MS hyphenated techniques. The metabolites that could not be identified by these methods were isolated from ethanolic extract of leaves of these species and identified by NMR 1H and 13C and MS. During this study it was noticed that the aging of the leaves results in a significant reduction on the rate of all the secondary metabolites. It was also possible to identify nine secondary metabolites belonging to caffeoylquinic acids, phenolical derivatives and flavonoids, from which, three compounds were isolated, however two compounds wasnt described in the literature. Relating to the seasonal variation, it was possible to verify that the individuals present similar metabolic profiles with quantitative differences but practically without qualitative difference. It was also possible to observe that there is a diversified metabolism in which not all individuals present an increase in the production of the same metabolite on a specific season. Despite these variations, it is possible to define autumn and spring as the seasons that presented the best rates of production on practically all the analyzed metabolites. Finally, it is possible to conclude that the seasonal variation of E. glomerutalus is significant and decisive to define the right time for future collection for further chemical and pharmacological studies.
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ION EXCHANGE CHROMATOGRAPHY COUPLED TO INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY: A POWERFUL TECHNIQUE FOR STABILITY CONSTANT DETERMINATION, SPECIATION ANALYSIS AND KINETIC STUDIESXING, LIYAN 30 September 2010 (has links)
Facile procedures based on hyphenated ion-exchange chromatography (IEC) and inductively coupled plasma mass spectrometry (ICP-MS) were developed to determine conditional stability constants, speciate chromium species and investigate the reduction of Cr(VI).
1. Improvements were made to a method previously developed to determine the conditional stability constant, Kf’, and chelation number, n, using IEC-ICP-MS. This method allowed the accurate determination of the conditional stability constant of a simple system. However, the corresponding chelation number was significantly different to the expected value because the principal assumption, i.e. that the ligand was in excess, was not realized in the experimentation. Furthermore, it neglected complexes other than that formed with EDTA4-. By taking into account these factors, accurate Kf’ and n were obtained for Co-EDTA and Zn-EDTA systems.
2. A simple method was developed for chromium speciation analysis at sub-µg L-1 level in potable water by IEC-ICP-MS. Cr(VI) and Cr(III) were separated on IonPac® AG-7 guard column within 7.5 minutes using gradient elution with 0.1 M ammonium nitrate and 0.8 M nitric acid. H2 collision/reaction interface gas eliminated chlorine-based and carbon-based polyatomic interferences on Cr detection. Water samples were analyzed directly, without any pretreatment. The accuracy of the method was verified through accurate analysis of riverine water certified reference material. Limits of detection of 0.02 and 0.04 µg L-1 for Cr(VI) and Cr(III), respectively, were obtained.
3. This speciation analysis method was then used for kinetics studies of Cr(VI) reduction in acidified riverine water. Water was spiked with Cr(VI), with or without Cr(III), and evolution of each Cr species with time was monitored by speciation analysis, showing that the reduction of Cr(VI) was a pseudo first order reaction. By plotting the logarithm of the peak area ratio of the instant Cr(VI) concentration over that of the original spiking versus time, the reaction rate constant was obtained as the slope. The reduction rate increased with decreasing pH and increasing temperature. The activation energy of the reaction at pH 1.3 was calculated using an Arrhenius plot. This method offers the advantages of small sample consumption, minimal sample manipulation, and easy data interpretation. / Thesis (Ph.D, Chemistry) -- Queen's University, 2010-09-30 08:05:27.342
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Estudos das variações sazonais e intrapopulacional dos metabólitos secundários majoritários das folhas de \'Eremanthus glomerulatus Less\' (Asteraceae) / Study of the seasonal and intrapopulational variations of the secondary metabolites from the leaves of Eremanthus glomerulatus Less (Asteraceae).Juliano Geraldo Amaral 22 February 2008 (has links)
O trabalho buscou investigar as variações sazonais de metabólitos secundários em Eremanthus glomerulatus Less (Asteraceae). Embora não ser utilizada para fins medicinais esta espécie contem substâncias biologicamente ativas. Para este estudo, foram selecionados dez indivíduos de uma mesma população localizada na região do município de Ibiraci - MG, que durante um período de aproximadamente dois anos (06/2000 a 04/2002) tiveram um de seus ramos coletados mensalmente. Visando a análise das folhas destes ramos uma metodologia para extração e análise de seus metabólitos secundários majoritários por CLAE-UV foi desenvolvida e utilizada para determinação de suas variações sazonais. A identificação destes metabólitos se deu principalmente pelas técnicas hifenadas CLAE-DAD-EM e CLAE-DAD-EM/EM. Os metabólitos que não puderam ser identificados por estas ferramentas foram isolados do extrato etanólico foliar desta espécie e identificados por RMN de 1H e 13C e EM. Durante este estudo foi verificado que o envelhecimento das folhas resulta em uma significativa redução no conteúdo de todos os seus metabólitos secundários. Também foi possível identificar nove metabólitos secundários pertencentes as classes dos ácidos cafeoilquínicos, derivados fenólicos e flavonóides, dos quais foram isolados três, sendo dois ainda não relatados na literatura. Quanto a variação sazonal pode-se verificar que os indivíduos apresentam perfis metabólicos bem semelhante com diferenças quantitativas mas praticamente não apresentando variações qualitativas entre os indivíduos. Pode-se observar também que há um metabolismo bem diversificado no qual nem sempre todos os indivíduos apresentam aumento de produção de um mesmo metabólito em determinada estação do ano. Apesar das variáveis é possível definir o outono e a primavera como as estações que durante o estudo apresentaram os melhores índices de produção de praticamente todos os metabólitos analisados. Por fim pode-se concluir que as variações sazonais em E. glomerutalus são significativas e que são determinantes para definir a época de futuras coletas para posteriores estudos químicos ou farmacológicos. / This study was performed to investigate the seasonal intrapopulational variations of the secondary metabolites in Eremanthus glomerulatus Less (Asteraceae). Although this species is not used for medicinal purposes, it contains biologically active substances. For this study, ten individuals from the same population located in the region of Ibirici city, Minas Gerais state, had one of their lbranches collected monthly for about two years (from 06/2000 to 04/2002). Aiming the analysis of the leaves from the branches, a methodology on UV-HPLC was developed and used for the extraction and analysis of major secondary metabolites to determine the seasonal variations. The identification of the metabolites has occurred mainly by the HPLC-DAD-MS and HPLC-DAD-MS/MS hyphenated techniques. The metabolites that could not be identified by these methods were isolated from ethanolic extract of leaves of these species and identified by NMR 1H and 13C and MS. During this study it was noticed that the aging of the leaves results in a significant reduction on the rate of all the secondary metabolites. It was also possible to identify nine secondary metabolites belonging to caffeoylquinic acids, phenolical derivatives and flavonoids, from which, three compounds were isolated, however two compounds wasnt described in the literature. Relating to the seasonal variation, it was possible to verify that the individuals present similar metabolic profiles with quantitative differences but practically without qualitative difference. It was also possible to observe that there is a diversified metabolism in which not all individuals present an increase in the production of the same metabolite on a specific season. Despite these variations, it is possible to define autumn and spring as the seasons that presented the best rates of production on practically all the analyzed metabolites. Finally, it is possible to conclude that the seasonal variation of E. glomerutalus is significant and decisive to define the right time for future collection for further chemical and pharmacological studies.
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Mass Tourism and the Environment : A Translation Study of Terminology, Metaphors and Hyphenated Premodifiers in Two ArticlesLindblad, Cecilia January 2010 (has links)
The following essay is an analysis of a translation from English into Swedish of two articles concerning tourism, travelling and the environment. The language of the articles is expressive and rich in metaphors, which evokes images in the mind of the reader. The translation was performed with the aim to transfer this effect into the translated texts and the aspects to be examined in the analysis were chosen with this in mind.One of the three aspects to be examined is the use of metaphors and how they are translated into Swedish. Many of the metaphors bear reference to travelling and the environment which gives them a function of enforcing the message and engaging the reader in the text. In order to obtain the same effect in the Swedish translations several translation strategies had to be used.The second aspect to be examined is the terminology used within tourism and the environment. The environmental concern is a growing trend which inevitably influences the language and requires a new set of useful and understandable terms. This becomes clear when reading and translating the articles at hand. The environmental terms are fairly new and sometimes hard to distinguish. In this study focus is set on the translation strategies and the procedures used in order to find the Swedish equivalents of the terms in this context.The third aspect is the translation of hyphenated pre-modifiers. This aspect is particularly interesting, since the phenomenon is more or less unknown in Swedish. Of the fifteen hyphenated pre-modifiers in the source texts none were translated into hyphenated pre-modifiers in Swedish although five of them were translated into regular pre-modifiers. The analysis is based on the translation strategies applied and the comparison of syntactic structures of the expressions in English and Swedish.
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Describing scent : On the translation of hyphenated premodifiers in a text about perfumeMagnusson, Evelina January 2021 (has links)
This small-scale study examines the translation of a text about perfumes, focusing on how hyphenated premodifiers in the English source text were translated into Swedish. A quantitative analysis was carried out, where the various premodifying structures present in the source text were identified and categorized according to their individual constituents and frequencies of the various categories were calculated. A similar analysis was also performed regarding the corresponding structures found in the Swedish target text. The results were then compared to and contrasted with other recent studies. In the qualitative analysis, individual examples from the text were analysed more in depth, and the consequences of the translation choices made were discussed. The results demonstrated that English hyphenated premodifiers showed a great deal of structural variety. The most frequent structures were nouns occurring in the left-hand position and ed-participles occurring the right-hand position. A large majority of the hyphenated premodifiers were short, with only 5.5% consisting of three words or more. The results also showed that the most frequent corresponding structure in the Swedish target text were compound adjectives, which comprised 48.1% of all examples. The results of the qualitative analysis pointed at a tendency towards explication, especially when hyphenated premodifiers were restructured to postmodifying phrases and clauses. Furthermore, a tendency to simplify the hyphenated modifiers during the translation process was noted, especially when translating longer, phrasal modifiers. It was noted that many hyphenated premodifiers in the ST were metaphorical in nature. This was sometimes, but not always, also the case in the corresponding TT phrases.
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Hyphenated fourier transform infrared spectrometry: techniques for separations and analysisJordan, Sheri Lynne 28 August 2003 (has links)
The following work describes the instrumentation and application of hyphenated FT-IR techniques specifically involving supercritical fluid extraction (SFE), supercritical fluid chromatography (SFC), and liquid chromatography (LC). Three studies are presented. The first involves the application of SFE/FT-IR towards the extraction of finishes from textile fibers. SFE has previously been applied to less complex finish systems. The proposed method making use of intermediate trapping is viable for more complex systems that show limited solubility in a supercritical fluid. Quantification of the percent finish on yarn was performed and results were favorable when compared with plant data. The range of applications was expanded to on-line SFE/SFC in the extraction and analysis of components from the polymer matrix itself. SFE/SFC/FT-IR was used to identify extractable components from a variety of Nylons. Following identification of one of the primary extractables, caprolactam, SFE/SFC was used to quantitate the amount of residual starting material in a Nylon copolymer. The second study involves the extractables in polystyrene which is a softer polymer with respect to solubility of components in supercritical CO ₂. Dimers and trimers as well as processing agents were identified via FT-IR with relatively mild supercritical extraction conditions.
Following these two studies was the expansion of hyphenated FT -IR to mobile phase elimination. A system optimization was carried out using polymer additive standards. The effects of nebulizer flow, sheath flow, and sheath temperature were shown. The data were analyzed at in terms of library matches as well as GramSchmidt reconstruction peak heights. Peak intensities were the primary source for choosing optimum conditions. Under optimized conditions, approximately 200 ng of analyte were analyzed and found to be above the limit of detection.
The applicability of the interface was demonstrated by the identification/analysis of triclosan, an antibacterial agent, in Colgate toothpaste. Aside from the identification of the analyte this study was used to show the effect of deposition parameters such as disk rotation rate as well as the effectiveness of FT-IR spectral library searches. The analysis of triglycerides was also carried out to show the effectiveness of using LC/FTIR for viscous liquids which are difficult analytes to deposit onto a solid substrate.
Using this FT-IR technique allowed one to look at the degree of saturation/unsaturation in an olive oil sample. The linearity of the method was shown using a set of triglyceride standards.
Lastly, the feasibility of using the commercially manufactured mobile phase elimination interface for SFC was demonstrated. Additive standard was deposited using both pure and methanol modified CO₂. No effluent split mechanism was used for decompressed flows up to 150 mL/min. Detection limits are proposed to fall in the low (10 - 25) ng range. The infrared spectra are enhanced over those acquired with a flow cell interface because CO₂ absorbance bands no longer obscure a portion of the analyte absorption spectrum. / Ph. D.
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The translation of cultural references and hyphenated premodifers in a travel guide about the CaribbeanHiltunen, Nina January 2018 (has links)
This paper studies how cultural references and hyphenated premodifiers in an English travel guide about the Caribbean are translated into Swedish. The aim is to investigate what strategies that are used when translating cultural references, and why; as well as to see which grammatical structures that appear when translating hyphenated premodifiers from English to Swedish. The qualitative analysis focuses on how cultural references and hyphenated premodifiers are translated, the strategies/categories used, and the corresponding result. The quantitative analysis aims at summarizing what strategies or grammatical categories that are most commonly used in overcoming these translation issues. The results show that most hyphenated premodifiers are translated with another grammatical structure, namely through premodifying adjectives, without the use of hyphens. Regarding cultural references, equivalence, transference, and generalization were common strategies to convey the same content and sense to the new target readers, whereas the domesticating method together with communicative translation proved to be the most helpful methods.
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Íránská diaspora v USA / Iranian Diaspora in the United StatesHavlů, Veronika January 2012 (has links)
This dissertation seeks to explore the social reality of Iranians living in the United States. The main objective is to find out how Iranians (Iranian Americans) maintain, construct and perceive their Iranian identity and to identify factors that could intervene in this process. Another aim is to examine intra-diasporic social relations, social interactions with American society and stance towards Iran. To fulfill the purpose of this dissertation, a qualitative research method was applied. The selected qualitative data consisted of thirty-one in-depth interviews with Iranians in New York City and Los Angeles. The results of the research indicated a strong sense of Iranian pride among all respondents, regardless their religious, inner ethnic or generational affiliation. This pride stems from ancient Iranian cultural heritage (and from Pahlavi era that adopted ancient symbolism into its ideological repertoire) and is still kept alive through pre-Islamic symbols and religiously indifferent traditions. It is obvious that the "pure Iranian identity" belongs to the first generation Iranians only, while the 1.5 and second generations, in their self-concept, proved to be rather hyphenated or torn between three spaces (typically young Iranian Jews). Research revealed their identity is oftentimes chosen,...
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