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Amine-oxide adsorbents for post-combustion CO₂ captureBollini, Praveen P. 12 January 2015 (has links)
Amine functionalized silicas are promising chemisorbent materials for post-combustion CO₂ capture due to the high density of active sites per unit mass of adsorbent that can be obtained by tuning the synthesis protocol, thus resulting in high equilibrium CO₂ adsorption capacities. However, when compared to physisorbents, they have a few disadvantages. Firstly, oxidative degradation of the amine groups reduces the lifetime of these adsorbent materials. Furthermore, rapid heat release following the reaction between amines and CO₂ results in large local temperature spikes which may adversely affect adsorption equilibria and kinetics. Thirdly, there is a lack of fundamental understanding of CO₂-amine adsorption thermodynamics, which is key to scaling up these materials to an industrial-scale adsorption process. In this dissertation the qualitative and quantitative understanding of these three critical aspects of aminosilica adsorbents have been furthered so these materials can be better evaluated and further tuned as adsorbents for post-combustion CO₂ capture applications.
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Amine-functionalized polymeric hollow fiber sorbents for post-combustion CO₂ captureLi, Fuyue 12 January 2015 (has links)
Polymeric hollow fiber sorbents were functionalized with amine moieties for improving the carbon dioxide sorption capacity from flue gas to reduce the greenhouse gas emissions from coal-fired power plants. Three different experimental pathways were studied to form the amine-functionalized hollow fiber sorbents. Aminosilane functionalized cellulose acetate (CA) fibers, polyethyleneimine (PEI) functionalized polyamide-imide (PAI, Torlon® fibers and PEI post-infused and functionalized Torlon®-silica fibers were formed. CO₂ equilibrium sorption capacity data were collected by using the pressure decay sorption cell and thermal gravimetric analyzer. Other physio-chemical properties of the amine-functionalized fiber sorbents were characterized by using fourier-transform infrared spectroscopy, elemental analysis, and scanning electronic microscopy. Different reaction conditions were studied on the effect of sorption isotherms. Aminosilane-CA fibers were the first proof-of-concept for forming the amine functionalized polymer hollow fibers. PEI-PAI fibers were designed as a new method to reach enhanced sorption capacities than Aminosilane-functionalized CA fibers. PEI post-infused and functionalized Torlon®-silica fibers have further enhanced sorption capacity; however they easily degrade with similar reaction for forming PEI-PAI fibers. Lumen-side barrier layers were created successfully via post-treatment technique of using the crosslinked Neoprene® polymer onto PEI-functionalized PAI fibers. PEI-functionalized PAI fibers also have good cyclic stability and low heat of sorption.
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A control-centralised multiaccess protocol exploiting non-selective fading for LEO satellite communicationsRen, Weili January 2001 (has links)
No description available.
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Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) for the Study of Noncovalent ComplexesHeath, Brittany 19 July 2012 (has links)
Mass spectrometry has become an important tool for analysis of protein complexes. This study utilizes electrospray ionization (ESI) coupled to a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) to analyze noncovalent complexes in the gas phase. Binding of cucurbit[7]uril (CB7) to intact bovine insulin and the B-chain of insulin was investigated. Competition experiments involving the B-chain and a mutant B-chain were performed to probe the solution-phase binding site. Electron capture dissociation (ECD) of CB7 complexed to intact insulin and to the B-chain, produced a series of peptidic fragments of insulin in complex with CB7. Analysis of these fragments allowed the determination of the apparent gas-phase binding site, which appears different than the proposed solution-phase binding-site. These studies thus suggest that CB7 migrates when the complex is transferred from solution to gas phase. The results of this study caution against using ECD-MS as a stand-alone structural probe of solutionphase binding.
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Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) for the Study of Noncovalent ComplexesHeath, Brittany 19 July 2012 (has links)
Mass spectrometry has become an important tool for analysis of protein complexes. This study utilizes electrospray ionization (ESI) coupled to a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) to analyze noncovalent complexes in the gas phase. Binding of cucurbit[7]uril (CB7) to intact bovine insulin and the B-chain of insulin was investigated. Competition experiments involving the B-chain and a mutant B-chain were performed to probe the solution-phase binding site. Electron capture dissociation (ECD) of CB7 complexed to intact insulin and to the B-chain, produced a series of peptidic fragments of insulin in complex with CB7. Analysis of these fragments allowed the determination of the apparent gas-phase binding site, which appears different than the proposed solution-phase binding-site. These studies thus suggest that CB7 migrates when the complex is transferred from solution to gas phase. The results of this study caution against using ECD-MS as a stand-alone structural probe of solutionphase binding.
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Capturing Human Hand Kinematics for Object Grasping and ManipulationGhosh, Shramana 03 October 2013 (has links)
The aim of this thesis is to create a low-cost sensor equipped glove using commercially available components that can be used to obtain position, velocity and acceleration data for individual fingers of a hand within an optical motion capture environment. Tracking the full degrees of freedoms of the hand and finger motions without any hindrances is a challenging task in optical motion capture measurements. Attaching markers on every finger and hand joint makes motion capture systems troublesome due to practical problems such as blind spots and/or obtaining higher derivative motion constraints, such as velocities and accelerations. To alleviate this, we propose a method to capture the hand and finger kinematics with a reduced set of optical markers. Additionally inertial sensors are attached to the fingertips to obtain linear acceleration measurements. For optimal velocity estimation, a Kinematic Kalman Filter (KKF) is implemented and its result is compared to the time derivative of the Motion Capture System measurement. The higher derivative specifications are related to contact and curvature constraints between the fingers and the grasped object and are later used in formulating the synthesis task for the design of robotic fingers and hands. A preliminary prototype device has been developed to obtain position, velocity and acceleration information of each fingertip by incorporating multiple accelerometers into the basic design of reduced marker set.
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Implicit and explicit capture of attention: what it takes to be noticedvan Rij, Nathan Gordon January 2007 (has links)
Two Inattentional Blindness type experiments involving 446 participants were performed in order to examine how unexpected objects are noticed. Perception of these unexpected objects was measured using explicit and implicit measurements. Despite initial difficulty in determining implicit perception, results showed a dissociation between implicit measurements and explicit measurements, providing strong evidence for unconscious processing. Research into attention capture often emphasizes the role of either expectations or stimulus properties in attention capture; the current research examines both. Critical objects presented were either of a colour that participants were familiar with, or of a new colour. The different patterns of results for these two categories of objects provide evidence for two separate mechanisms of attention capture: a parallel process driven by the features of objects, and a serial process, driven by the intentions of the observer. Predications of the recent theoretical work produced by Most, Scholl, Clifford & Simons, (2005) are examined, and support is obtained for their theoretical formulation.
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The synthetic and bioinorganic chemistry of carboranes /Schaffer, Paul. Valliant, John Fitzmaurice. January 1900 (has links)
Thesis (Ph.D.)--McMaster University, 2003. / Advisor: John Fitzmaurice Valliant. Accompanying CD-ROM contains the text, plus additional material (appendices I and II). Includes bibliographical references. Also available via World Wide Web.
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Modelling convective dissolution and reaction of carbon dioxide in saline aquifersCherezov, Ilia January 2017 (has links)
In an effort to reduce atmospheric carbon dioxide (CO2) emissions and mitigate climate change, it has been proposed to sequester supercritical CO2 in underground saline aquifers. Geological storage of CO2 involves different trapping mechanisms which are not yet fully understood. In order to improve the understanding of the effect of chemical reaction on the flow and transport of CO2, these storage mechanisms are modelled experimentally and numerically in this work. In particular, the destabilising interaction between the fluid hydrodynamics and a density-increasing second-order chemical reaction is considered. It is shown that after nondimensional scaling, the flow in a given physicochemical system is governed by two dimensionless groups, Da/Ra2, which measures the timescale for convection compared to those for reaction and diffusion, and CBo', which reflects the excess of the environmental reactant species relative to the diffusing solute. The destabilising reactive scenario is modelled experimentally under standard laboratory conditions using an immiscible two-layer system with acetic acid acting as the solute. A novel colorimetric technique is developed to infer the concentrations of chemical species from the pH of the solution making it possible to measure the flux of solute into the aqueous domain. The validity of this experimental system as a suitable analogue for the dissolution of CO2 is tested against previous work and the destabilising effect of reaction is investigated by adding ammonia to the lower aqueous layer. The system is also modelled numerically and it is shown that the aqueous phase reaction between acetic acid and ammonia can be considered to be instantaneous, meaning that Da/Ra2 tends to infinity and the flow is therefore governed only by the initial dimensionless concentration of reactant in the aqueous phase. The results from the experiments and numerical simulations are in good agreement, showing that an increase in the initial concentration of reactant increases the destabilising effect of reaction, accelerates the onset of convection and enhances the rate of dissolution of solute. The numerical model is then applied to a real world aquifer in the Sleipner gas field and it is demonstrated how the storage capacity of a potential CO2 reservoir could be enhanced by chemical reaction.
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The Coulomb capture of muons and pions in complex matterLewis, Douglas R. January 1993 (has links)
The investigation of exotic particle capture in complex media is studied in this thesis. An investigation into the best one-step Born-type approximation for the Auger capture rate of mu-is made for a H target. It is concluded that a distorted Born-approximation in which the shielding effect of the atomic electrons is included in the determination of the Coulomb continuum wavefunctions is the most appropriate and computationally efficient method of calculation. Generalisation of this method for Auger capture in light atoms is then studied with the ejection of 1s, 2s, 2p, 3s and 3p electrons examined. The focus of the investigation is on the dependence of the Auger rate on the type of electron, the final mu-bound state, and the collision centre of mass energy. It is discovered that the outermost electrons of an atom are the most effective capture electrons with Auger rate maxima as a function of the principal quantum number n occurring at approximately n = 14, n = 30 and n = 40 for the K, L and M-shell s and p electrons. The Auger rate curves as a function of the angular momentum I reach a maximiim between I = 10 and I = 20 dropping rapidly thereafter. An attempt is also made at predicting pi-Auger capture rates into (pppi-)+ molecular orbitals, however the results are schematic and serve only as an example of the method of calculation. Differences between the initial distributions required by the cascade code EXCAS to fit the X-ray data from essentially atomic targets and molecular targets have been determined. A modified statistical distribution with small positive a's is required for the noble gas atoms with a very highly ionised atom resulting at the n = 14 stage for mu-. The oxygen and carbon atoms in simple molecules require a small negative a with again a depleted electron population at the n = 17 stage for pi-. By extending the cascade code EXCAS to larger starting values and inputing a population of mu- for every bound quantum state the properties and de-excitation behaviour of the Ne muonic atom is studied. Results show that depending upon if electron refilling rates are fast or slow an approximate modified distribution with a positive a at the n = 14 state can be attained by a statistical input distribution of mu- or a distribution peaked in I around I = n/2 respectively. The second distribution agrees with the previous results for Auger capture in light atoms.
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