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The analysis of salt resistant surfactants used in enhanced oil recoveryBenomar, Salim Hmada A. January 2001 (has links)
Commercial nonylphenol ethoxysulphonate (NPEOS), octylphenol ethoxysulphonate (OPEOS) surfactant formulations and mixtures of alkyl aryl sulphonate and NPEOS surfactant formulations, are used for enhanced oil recovery (EOR). The surfactants have been analysed by liquid chromatography (LC), liquid chromatography-mass spectrometry (LC-MS) and matrix assisted laser desorption ionization mass spectrometry. Mixedmode C1 8/SAX and C8/SAX columns were used for both liquid chromatography and liquid chromatography-mass spectrometry analyses of NPEOS and OPEOS. NPEOS and alkyl aryl sulphonate surfactant mixtures were separated using a mixed-mode C4/SAX column. Matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) spectra were obtained using either alpha-cyano-4-hydroxycinnamic acid or 2,5-dihydroxybenzoic acid as matrix with the addition of lithium chloride to simplify the mass spectra obtained. Data obtained from each method indicate that the NPEOS formulation has an ethoxymer chain length ranging from 2-13 units with average of 6.26. This is in broad agreement with earlier studies, although the range was reported as 2-15. However, the data obtained suggest that the OPEOS formulation has an ethoxymer chain length ranging from 1-8 ethoxymer units with an average chain length of 3.67. This is in contrast to earlier studies carried out by LC only, which suggested that the chain length ranged from 2 to 6 ethoxymer units with an average of 3.6. A method for the extraction of NPEOS and OPEOS from sea-water and reagent water, and alkyl aryl sulphonate from sea-water only, using graphitised carbon black (GCB) solid phase extraction (SPE) cartridges has also been developed. In the last section of this thesis the chemical oxidation of NPEOS used Fenton's reagent and biological oxidation of NPEOS using a microorganism (Paracoccus halodenitrificans) is reported. The intermediate products formed in the chemical oxidation have been identified and characterized by LC, LC-ES-MS and MALDI/MS techniques. The major products formed are dicarboxylic acids and single carboxylic acids. The aerobic biodegradation of NPEOS was carried out over five days. Theoxygen uptake was measured each day. The biodegradation intermediate products were analysed by LC and data indicate that the same products were formed as those from the chemical oxidation of NPEOS.
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The individual development plan as tool and practice in Swedish compulsory schoolHirsh, Åsa January 2013 (has links)
Since 2006 Swedish compulsory school teachers are required to use individual developmentplans (IDPs) as part of their assessment practices. The IDP has developed through two major reforms and is currently about to undergo a third in which requirements for documentation are to be reduced. The original purpose of IDP was formative: a document containing targets and strategies for the student's future learning was to be drawn up at the parent-pupil-teacher meetingeach semester. The 2008 reform added requirements for written summative assessments/grade-like symbols to be used in the plan. This thesis aims to generate knowledge of the IDP as a tool in terms of what characterizes IDP documents as well as teachers' descriptions of continuous IDP work. It contains four articles. The first two are based on 379 collected IDP documents from all stages of compulsoryschool, and the last two build on interviews with 15 teachers. Throughout, qualitative content analysis has been used for processing data. The analytical framework comprises Latour's conceptual pair inscription – translation, Wartofsky's notions of primary/secondary/tertiary artifacts, and Wertsch's distinction between mastery and appropriation, which together provide an overall framework for understanding how the IDP becomes a contextually shaped tool that mediates teachers' actions in practice. Moreover, the activity theoretical concept of contradictionis used to understand and discuss dilemmas teachers experience in relation to IDP. In article 1, targets and strategies for future learning given to students are investigated and discussed in relation to definitions of formative assessment. Concepts were derived from the data and used for creating a typology of target and strategy types related either to being aspects (students' behavior/attitudes/personalities) or to subject matter learning. In article 2, the distribution of being and learning targets to boys and girls, respectively, is investigated. The results point to a significant gendered difference in the distribution of being targets. Possible reasons for the gendered distribution are discussed from a doing-gender perspective, and the proportion of being targets in IDPs is discussed from an assessment validity point of view. In article 3, teachers' continuous work with IDPs is explored, and it is suggested that IDP work develops in relation to perceived purposes and the contextual conditions framing teachers' work. Three qualitatively different ways of perceiving and working with IDP are described in a typology. Article 4 elaborates on dilemmas that teachers experience in relation to IDP, concerning time, communication, and assessment. A tentative categorization of dilemma management strategies is also presented. Results are synthesized in the final part of the thesis, where the ways in which documents are written and IDP work is carried out are discussed as being shaped in the intersection between rules and guidelines at national, municipal and local school level, and companies creating solutions for IDP documentation. Various purposes are to be achieved with the help of the IDP, which makes it a potential field of tension that is not always easy for teachers to navigate. Several IDP-related difficulties, but also opportunities and affordances, are visualized in the studies of this thesis. / <p>Svensk sammanfattning: s. 111-126.</p>
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