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Impact of Video Presentation Features on Instructional Achievement and Intrinsic Motivation in Secondary School LearnersBland, Ronald B. 12 1900 (has links)
This study analyzed instructional achievement and intrinsic motivation among 21st century secondary students utilizing a video lecture incorporating both student reaction cutaway images and immediate content interaction within the lecture. Respondents (n = 155) were from multiple classes and grade levels at a suburban Texas high school. Four groups of students viewed the identical lecture with differing video and content interaction treatments. Students responded to a pretest/posttest survey to assess academic achievement in addition to an intrinsic motivation instrument to assess student interest. Group one (the control group) viewed the 12 minute lecture without enhancement. A second group viewed the identical lecture with student reaction shots inserted in the video. Another group viewed the lecture with content question intervention inserted into the video. The final group saw the lecture with the student reaction shots and content question intervention combined in the video. A repeated measures multivariate analysis of variance (MANOVA) was used to compare results from a 14 item pretest/posttest. Combined, the groups showed no significance (p = .069) indicating no associations were identified by the experiment. Although no association was identified, this may be a reflection of the generic nature of the video lecture and the lack of association with the experiment and actual classroom content within their courses. Students also completed the Intrinsic Motivation Instrument which was analyzed using a MANOVA. Although no significant findings were present in either group viewing the student reaction or the content question interaction treatments individually, the group viewing the combined treatment showed significance in three scales: Interest/Enjoyment (p = .007), Perceived Competence (p = .027) and Effort/Importance (p = .035) Recommendations for refinement of the current experiment as well as future studies are provided.
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Photoelectron Resonance Capture Ionization Aerosol Mass Spectrometry of Organic Particulate MatterZahardis, James 23 June 2008 (has links)
Organic aerosols are ubiquitous to the lower atmosphere and there is growing concern about their impact on climate and human health. These aerosols typically have multicomponent compositions that change over time in part due to oxidation by reactive trace gases, such as ozone. A current challenge to the atmospheric research community is to develop better methods of analysis of these particles. Photoelectron resonance capture ionization aerosol mass spectrometry (PERCI-AMS) is an online mass spectrometric method that has been applied to the analysis of organic aerosols. One of its key advantages is that it employs low energy (~ 0 eV) photoelectrons in the ion forming process, which has been shown to minimize fragmentation in the organic analytes, thus simplifying mass spectral interpretation. This dissertation focuses on the application of PERCI-AMS to the analysis of organic particles. Initial emphasis is placed on the heterogeneous reaction of gas phase ozone with liquid oleic acid particles. Products identified included carboxylic acids, aldehydes, and peroxides including alpha-acyloxyalkyl hydroperoxides polymers. The evidence of peroxidic products suggested the stabilization of carbonyl oxide intermediates (i.e. Criegee intermediates) that are formed during ozonolysis. Subsequent PERCI-AMS experiments investigated the reactivity of the stabilized Criegee intermediates. This included investigating the reaction of Criegee intermediates with unsaturated fatty acids and methyl esters. A novel ketone-forming reaction is described in these systems, suggesting the Criegee intermediates can react at a carbon-carbon double bond. Further PERCI-AMS experiments investigated the oxidative processing of particulate amines including octadecylamine and hexadecylamine. Ozonolysis of these amines resulted in strong NO2 - and NO3 - ion signals that increased with the ozone exposure and suggested a mechanism of progressive oxidation. Additionally, a strong ion signal was detected for NO3 -(HNO3), which is the ion core of the most important ion cluster series in the troposphere, NO3 -(HNO3)n(H2O)m. PERCI-AMS was applied to the analysis of ozonized mixed particles of amines with oleic acid or dioctyl sebacate. In the ozonolysis of the amines with oleic acid, products included imines and amides. The routes to the amides were shown to most likely arise from the reactivity of stabilized Criegee intermediates and/or secondary ozonides with the amines. There was also direct evidence of the formation of a surface barrier in the octadecylamine and oleic acid reaction system, which resulted in the retention of oleic acid at high ozone exposures. These experiments have fostered a better understanding of the analytical capacity of PERCI-AMS in assaying the reactivity of organic aerosols as well as giving a more accurate description of the heterogeneous chemistry of these challenging reaction systems. Suggestions for adaptations to PERCI-AMS and future experiments on
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Optimisation and integration of membrane processes in coal-fired power plants with carbon capture and storageBocciardo, Davide January 2015 (has links)
This thesis investigates membrane gas separation and its application to post-combustion carbon capture from coal-fired power plants as alternative to the conventional amine absorption technology. The attention is initially focused on membrane module modelling, with the aim of obtaining more detailed predictions of the behaviour of the separation though spiral-wound and hollow-fibre modules. Both one- and bi-dimensional models are implemented, compared and tested for different separations. Module geometry is investigated as well as the effect on the performances due to possible fabrication defects. A key part of the work involves the integration of the customised models into UniSim® Design, the Honeywell process simulator. Thanks to the developed interface, multi-stage process designs are developed, compared with the available literature and linked to a rigorous economic analysis. In particular, a long-term indicator such as the Levelised Cost Of Electricity (LCOE) is evaluated and parametric analyses are conducted with respect to both material and process parameters.
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A regulatory capture explanation of South Africa's private health insurance legislationHutcheson, Hugh-David 25 January 2012 (has links)
Private healthcare financing in South Africa has undergone several
regulatory reforms, the most recent of which saw the enactment of the
Medical Schemes Act No. 131 of 1998. The stated reforms, most
especially open enrolment and community rating, were touted by the
government as necessary to address the undesirable effects of adverse
selection. However, it was never questioned whether in fact adverse
selection is a feature of the South African medical schemes landscape.
Adverse selection is found to be absent. Thus, government’s supposition
that adverse selection, as a consequence of the deregulation that took place
during the late 1980s and early 1990s, is responsible for the deterioration in
medical scheme coverage for the elderly, unhealthy or poor is fallacious.
Since the ostensible reason for the current legislation does not stand up to
scrutiny, regulatory capture is offered as the plausible alternative
explanation for the promulgation of the current legislation governing
medical schemes business.
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Electron capture dissociation of peptides adducted with transition metal ions. / CUHK electronic theses & dissertations collectionJanuary 2011 (has links)
As an additional study, effect of tyrosine nitration on the BCD of protonated and metalated peptides was investigated. Some fragment ions that were inhibited in the ECD of protonated peptides were liberated in the ECD of metalated peptides. By theoretical calculation of the cation-pi and cation-nitro group coordination using the metal ions nitrated phenol complex as a model, it is found that the metal ions might favor coordinating with the nitro group of the nitrated tyrosine residue in the peptides. / In order to improve the performance of the electron capture dissociation (BCD) mass spectrometry for structural analysis of peptides/proteins, BCD of peptides cationized with various transition metal ions was investigated. It was found that peptides adducted with different divalent transition metal ions generated different BCD tandem mass spectra. For Mn2+and Zn2+, the incoming low-energy electron would not favor being trapped by the metal ions and instead trigger the usual BCD dissociation channel(s) via "hot-hydrogen" or "superbase" intermediates to form a series of c-/z·- fragments. For other first row transition metal ions, including Fe2+, Co2+, Ni 2+and Cu2+, reduction of the metal ions occurs preferentially during the electron capture event and lead to the formation of usual "slow-heating" type of fragment ions, i.e. metalated a-/y-fragments & metalated b-/y- fragments. / To further compare the behavior of metal ions with the same electronic configuration, BCD of Group IIB metal ions adducted peptides were investigated. In contrast to the ECD behavior of Zn2+ adducted peptides, peptide radical cations (M+· ) and fragment ions corresponding to losses of neutral side chain from M+· were observed in the ECD spectra of Hg2+ and Cd2+ adducted peptides. The experimental observations appeared to depend on the balance of the ionization energy of peptide and the solvation modulated ionization energies of the metal atom. The reduction of divalent metal ions by the electron capture event could induce spontaneous electron transfer from the peptide moiety to the monovalent metal centre and generate hydrogen-deficient M +· species. / Chen, Xiangfeng. / Adviser: T.-W. Dominic Chan. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 131-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
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A DLTS system for semiconductor characterization: application to Ar+ implanted Sb/Si system.January 1988 (has links)
by Siu-Chung Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 98-102.
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Joint estimation in optical marker-based motion captureHang, Jianwei January 2018 (has links)
This thesis is concerned with the solutions to several issues, including the problems of joint localisation, motion de-noising/smoothing, and soft tissue artefacts correction, in skeletal motion reconstruction for motion analysis, using marker-based optical motion capture technologies. We propose a very efficient joint localisation method, which only needs to optimise over three parameters, regardless of the total numbers of markers and frames. A framework powered by this joint localisation solution is also developed, which can automatically find all the joints in an articulated body structure, and significantly reduce the total number of markers needed in a typical motion capture session, by implementing a solvability propagation process. This framework is also configured to operate in a hybrid scheme, which can automatically switch between the primary joint estimator and a slower solution having fewer conditions regarding the required number of markers on a given body segment. This makes the framework workable even for extreme scenarios in which there are fewer than three markers on any body segment. A non-linear optimisation method for 3D trajectory smoothing is also proposed for de-noising the estimated joint paths. By immobilising a series of characteristic points in the trajectory, this method is able to effectively preserve detailed information for vigorous motion sequences. Various other smoothing techniques in the literature are also discussed and compared, concluding that a size-3 weighted average filter implemented in an automatic manner is a good real-time solution for low intensity activities. The effects of skin deformation on marker position data, known as soft tissue artefacts, are learned via a behavioural study on the human upper-body, with specific emphasis on combined limb actions. Based on the experimental findings, mathematical models are proposed to characterise the development of different types of artefacts, including translational, rotational, and transverse. We also theoretically demonstrate the feasibility of using a Kalman filter to correct the soft tissue artefacts, using the mathematical models.
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Development of functionalised porous carbon materials for the separation of carbon dioxide from gas mixturesGibson, John Alastair Arran January 2016 (has links)
This work concerns the functionalisation of a variety of carbon materials for the selective adsorption of carbon dioxide. A key challenge in post-combustion capture from gas fired power plants is related to the low CO2 concentration in the flue gas (4- 8%). Therefore highly selective adsorbents have the potential to improve the efficiency of the separation of carbon dioxide from gas mixtures. The study was performed in conjunction with the EPSRC funded project ‘Adsorption Materials and Processes for Carbon Capture from Gas-Fired Power Plants – AMPGas’. The carbon materials investigated included multi-walled carbon nanotubes, a microporous activated carbon, two types of mesoporous activated carbon and multi-walled carbon nanotube/polyvinyl alcohol composite aerogels. The uptake of carbon dioxide by these materials was enhanced through the addition of basic amine groups to the materials. The adsorption properties of the samples were tested by the zero-length column technique, thermal gravimetric analysis and breakthrough experiments. The materials were generally tested at conditions representative of those found in the flue gas of a fossil fuel power plant: 0.1 bar partial pressure of CO2. Two approaches were adopted for the chemical functionalization of the solid carbon supports. First, amine groups were covalently grafted directly to the surface and secondly amine molecules were physically adsorbed within the porous structure of the material by wet impregnation. It was seen that wet impregnation enabled the incorporation of a greater number of amine groups and the CO2 capacity of the materials was investigated with respect to the carbon support structure, the type of amine and the amount of amine loading. Larger pore volume mesoporous carbon materials were seen to provide a more efficient support for the amine to interact with the CO2. A greater than 12-fold increase in the CO2 capacity was observed when the amine impregnated carbon material was compared to the raw starting material. The extended zero-length column was introduced and fully characterized as a novel breakthrough experiment. It requires a small sample mass (~50 mg) and it allows binary selectivities to be calculated. It was shown, through multiple experiments and simulations that the breakthrough experiments were conducted under close to isothermal conditions which greatly simplifies the analysis of the breakthrough curves. In addition, a new zero-length column model was proposed to account for the reaction between the amine and the CO2 in the adsorbed phase and fitted to experimental data. An interesting double curvature was observed in the concentration profile during the desorption step which was attributed to the kinetics of the amine-CO2 reaction. A brief investigation was carried out into the binary separation of biogas (45% CO2: 55% CH4) by zeolite 13X, activated carbon and an amine impregnated activated carbon. Finally, initial investigations into the properties of low density carbon nanotube aerogels which have a large accessible pore volume, were carried out. Their potential as highly efficient supports for amine impregnation was investigated. It was found that amine functionalized carbons strongly interact with carbon dioxide and have the potential to be integrated as an adsorbent in a rapid temperature swing process that separates carbon dioxide from dilute gas streams.
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Carbon dioxide absorption in metal organic frameworksGao, Min January 2015 (has links)
With the emission of carbon dioxide (CO2) becoming an international worry due its role in climate change, solutions such as CO2 capture and storage technologies are needed to decrease the emissions. The main proportion of CO2 gas emissions is from fossil fuel combustion in a range of industries, including power generation. To develop the CO2 capture system for these operations, new materials are needed for CO2 capture. Metal-organic framework (MOF) materials have porous crystal structures containing organic molecules (organic ligands) linked to each other by metalcontaining nodes. The large internal surface area can be exploited for the adsorption of small gas molecules, and for this reason MOFs may be ideal candidate materials for CO2 capture and gas separations. Thousands of MOF materials have been reported, with different combinations of the ligands and metals and with the capability of forming many different network topologies. Experimentally it is very difficult to study the gas absorption dynamics, interaction and gas adsorption capacity for the large number of materials. This problem can be solved by simulations. The aim of the thesis is to develop a systematic simulation method to screen the MOF properties and CO2 adsorption capacity and interaction dynamics at different environment. The molecular dynamics (MD) method with parameterised force fields was used to study the interactions between CO2 molecules and one class of the MOFs, zeolitic imidizolate frameworks (ZIFs) with zinc as the metal cation. To develop the model, the atom charges have been developed by using the distributed multipole analysis (DMA) method based on ab initio DFT calculations for molecules and clusters. The intermolecular forces were developed by fitting against the MP2 calculations of small clusters of the metal cations and molecular ligands. In order to evaluate the models I simulated the gas-liquid coexistence curve of CO2 and showed that it is consistent with experiments. I also simulated the pure ZIF structures on changing both temperature and pressure, demonstrating the stabilities of the structures but also showing the existence of displacive phase transitions. I have used this approach to successfully study CO2 absorption in a number of ZIFs (from ZIF-zni, ZIF-2, ZIF-4, ZIF-8 and ZIF-10) using MD. The gas absorption capacity and dynamics have been investigated under 25 bar and 30 bar, 200 , showing a promising uptake of CO2. The results have shown that CO2 capacity is mainly determined by the pore sizes and pore surfaces, in which a higher capacity is associated with a higher pore surface. The intermolecular distance of CO2 inside the pores and channels have been investigated in the saturation state. It has been shown that the distance is approximately 4 Å. The attraction force is from the interaction between CO2 and the imidazolate ligands. In addition, the systematic studies of the saturated ZIF system gave the minimum diameters for CO2 adsorption which is approximately 4.4 Å. This interaction has caused the gate opening effects, with the imidazolate ligands being pushed to be parallel to the CO2 molecules and opening up to allow more gas molecules go through the channels that connect the pore structures. This gate opening effect also explains the phase transition in ZIF-10 caused by CO2 molecules in our simulation, and can be applied to predict phase transitions in other materials with similar structure such as ZIF-7 and ZIF-8. The dynamics have also shown that the gas diffusion velocity is determined by the pore structure as well and by the accumulated layers of CO2 on the surface prior to being pushed in toward the centre of the material layer by layer. The de-absorption processes have also been studied in these materials by decreasing the pressure from 25 bar to 1 bar under at same temperature. The results indicate that the de-absorption is a reverse process of absorption. The structure of ZIF-10 went through a phase transition induced by CO2 recovered after the guest molecules had been released. The de-absorption can be accelerated by increasing the temperature.
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Investigation of the effect of the precursor ion heterogeneity on the fragmentation of the model peptides under electron capture dissociation.January 2011 (has links)
Chen, Fan. / "October 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 85-91). / Abstracts in English and Chinese. / ABSTRACT --- p.III / 摘要 --- p.IV / ACKNOWLEDGENTS --- p.V / TABLE OF CONTENTS --- p.VI / LIST OF FIGURES --- p.VIII / LIST OF TABLES --- p.X / SYMBOLS AND ABBREVIATIONS --- p.XI / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Mass spectrometry in proteomics --- p.1 / Chapter 1.2 --- Fourier-transform ion cyclotron resonance mass spectrometry --- p.2 / Chapter 1.2.1 --- Introduction --- p.2 / Chapter 1.2.2 --- Ionization --- p.3 / Chapter 1.2.3 --- Ions in ICR --- p.4 / Chapter 1.2.4 --- Ions excitation and detection --- p.7 / Chapter 1.3 --- Tandem mass spectrometry --- p.8 / Chapter 1.4 --- Electron capture dissociation --- p.12 / Chapter 1.4.1 --- Features ofECD --- p.13 / Chapter 1.4.2 --- Two popular mechanisms for ECD --- p.14 / Chapter 1.4.2.1 --- The Cornell mechanism --- p.15 / Chapter 1.4.2.2 --- The Utah-Washington mechanism --- p.17 / Chapter 1.4.3 --- Recombination energy --- p.19 / Chapter 1.5 --- Outline of the present work --- p.21 / Chapter CHAPTER 2 --- INSTRUMENTATION AND EXPERIMENTAL --- p.22 / Chapter 2.1 --- Fourier-transform ion cyclotron resonance mass spectrometer --- p.22 / Chapter 2.1.1 --- Vacuum system --- p.24 / Chapter 2.1.2 --- Nanospray system --- p.26 / Chapter 2.1.3 --- Ion transfer system --- p.29 / Chapter 2.1.4 --- Infinity´ёØ cell --- p.29 / Chapter 2.1.5 --- Electron emission source --- p.31 / Chapter 2.1.6 --- Data acquisition system --- p.32 / Chapter 2.2 --- Experimental --- p.32 / Chapter 2.2.1 --- Simple ESI acquisition pulse program --- p.32 / Chapter 2.2.2 --- ESI-ECD acquisition pulse program --- p.35 / Chapter CHAPTER 3 --- FRAGMENTATION OF MODEL PEPTIDE IONS IN DIFFERENT CHARGE STATES UNDER ECD CONDITIONS --- p.38 / Chapter 3.1 --- Introduction --- p.38 / Chapter 3.2. --- Experimental --- p.41 / Chapter 3.2.1 --- Sequence design and sample preparation --- p.41 / Chapter 3.2.2 --- ECD under fourier-transform ion cyclotron mass spectrometer --- p.43 / Chapter 3.3 --- Results and discussion --- p.43 / Chapter 3.3.1 --- General features of ECD spectra --- p.43 / Chapter 3.3.1.1 --- ECD of RRRR --- p.43 / Chapter 3.3.1.2 --- ECD of KKKK --- p.47 / Chapter 3.3.2 --- Effect of charge state of precursor ions --- p.49 / Chapter 3.3.3 --- Effect of proton carriers --- p.52 / Chapter 3.3.4 --- Effect of proton carrier location --- p.54 / Chapter 3.4 --- Conclusions --- p.60 / Chapter CHAPTER 4 --- EFFECT OF PRECURSOR ION HETEROGENEITY ON ECD FRAGMENTATION --- p.62 / Chapter 4.1 --- Introduction --- p.62 / Chapter 4.2 --- Method --- p.63 / Chapter 4.2.1 --- Preferential dissociation index --- p.64 / Chapter 4.2.2 --- Precursor ion heterogeneity --- p.65 / Chapter 4.3 --- Results and discussion --- p.67 / Chapter 4.3.1 --- PDI in model peptides --- p.67 / Chapter 4.3.2 --- PIH and PDI in RRRR and KKKK --- p.71 / Chapter 4.3.3 --- PDI and PIH in two-lysine containing peptides --- p.73 / Chapter 4.3.4 --- PDI and PIH in other peptides --- p.80 / Chapter 4.4 --- Conclusions --- p.82 / Chapter CHAPTER 5 --- CONCLUSIONS --- p.83 / References --- p.85 / Chapter Appendix I: --- Pulse program for simple MS and MS/MS experiment --- p.92 / Chapter (A) --- Simple ESI FT-ICR MS experiment --- p.92 / Chapter (B) --- ESI ECD FT-ICR MS experiment --- p.95 / Chapter Appendix II: --- ECD spectra of AC-XAAAXAAAXAAAX-NH2 peptide series in different charge states --- p.99 / Chapter Appendix III: --- The PDI of the hypothetic peptide --- p.110 / Chapter Appendix IV: --- The PIH among the investigated system --- p.111
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