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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.
111

One and two point micro-rheology of hard sphere suspensions

Harrison, Andrew William January 2011 (has links)
The material that is covered in this thesis concerns the calibration and application of a set of optical tweezers to be used for one- and two-point micro-rheology experiments on hard sphere colloidal suspensions. The colloidal suspensions that were used in this study were all quasi-monodisperse density- and refractive index-matched PMMA particles that had a radii, a = 0:90 ± 0:05μm or a = 0:86 ± 0:07 for one-point microrheology experiments and radii a = 0:90 ± 0:05μm or a = 0:133 ± 0:010μm for the two-point micro-rheology experiments. By collecting the forward scattered light from a single optically trapped particle the particle's displacements in time were used to determine passive microviscosity, η(Passive) μ , for colloidal suspension in the range of 0:10 < Ø < 0:57 and comparison with literature data has been made and agreement found. Actively dragging an optically trapped particle through suspensions with volume fractions of the same range has yielded the active microviscosities, η(Active) μ , for both high and low shear regimes, displaying shear thinning behaviour. Comparison to literature data has been made and agreement found as well. Collecting the forward scattered light from two optically trapped particles has been used to determine the cross-correlated motion of the two particles in bare solvent and in suspensions with volume fraction Ø = 0:02. The friction coefficients ξ1;1 and ξ1;2 were extracted from the cross-correlated motion of the particles and agreement was found with theoretical predictions for bare solvent only. The suspensions with volume fraction Ø = 0:02 were found to have a friction coefficient ξ1;1 that was greater than what theory predicted with the suspension with bath particles a = 0:90 ± 0:05μm had the greater magnitude. The magnitude ξ1;2 was found to decrease for the suspension with bath particles of radius a = 0:133 ± 0:010μm and to increase for the suspension with bath particles a = 0:90 ± 0:05μm.
112

Programming Molecular Devices using Nucleic Acid Hairpins

Garg, Sudhanshu January 2016 (has links)
<p>Nucleic Acid hairpins have been a subject of study for the last four decades. They are composed of single strand that is </p><p>hybridized to itself, and the central section forming an unhybridized loop. In nature, they stabilize single stranded RNA, serve as nucleation</p><p>sites for RNA folding, protein recognition signals, mRNA localization and regulation of mRNA degradation. On the other hand, </p><p>DNA hairpins in biological contexts have been studied with respect to forming cruciform structures that can regulate gene expression.</p><p>The use of DNA hairpins as fuel for synthetic molecular devices, including locomotion, was proposed and experimental demonstrated in 2003. They</p><p>were interesting because they bring to the table an on-demand energy/information supply mechanism. </p><p>The energy/information is hidden (from hybridization) in the hairpin’s loop, until required.</p><p>The energy/information is harnessed by opening the stem region, and exposing the single stranded loop section.</p><p>The loop region is now free for possible hybridization and help move the system into a thermodynamically favourable state.</p><p>The hidden energy and information coupled with </p><p>programmability provides another functionality, of selectively choosing what reactions to hide and </p><p>what reactions to allow to proceed, that helps develop a topological sequence of events. </p><p>Hairpins have been utilized as a source of fuel for many different DNA devices. In this thesis, we program four different </p><p>molecular devices using DNA hairpins, and experimentally validate them in the</p><p>laboratory. 1) The first device: A </p><p>novel enzyme-free autocatalytic self-replicating system composed entirely of DNA that operates isothermally. 2) The second</p><p>device: Time-Responsive Circuits using DNA have two properties: a) asynchronous: the final output is always correct </p><p>regardless of differences in the arrival time of different inputs.</p><p>b) renewable circuits which can be used multiple times without major degradation of the gate motifs </p><p>(so if the inputs change over time, the DNA-based circuit can re-compute the output correctly based on the new inputs).</p><p>3) The third device: Activatable tiles are a theoretical extension to the Tile assembly model that enhances </p><p>its robustness by protecting the sticky sides of tiles until a tile is partially incorporated into a growing assembly. </p><p>4) The fourth device: Controlled Amplification of DNA catalytic system: a device such that the amplification</p><p>of the system does not run uncontrollably until the system runs out of fuel, but instead achieves a finite</p><p>amount of gain.</p><p>Nucleic acid circuits with the ability </p><p>to perform complex logic operations have many potential practical applications, for example the ability to achieve point of care diagnostics.</p><p>We discuss the designs of our DNA Hairpin molecular devices, the results we have obtained, and the challenges we have overcome</p><p>to make these truly functional.</p> / Dissertation
113

A Change of Two Cities: A Comparative Case Study on Gentrification

Thomas, Raemi 01 January 2017 (has links)
Before addressing how gentrification affects a community, there must be an explanation of how gentrification looks at a community. Tom Borrup in Protecting Cultural Space or Urban Re-colonization: When Do Cultural Districts Cross the Line? refers to cities as “cultural districts” and defines “progenitors” and “driving forces” (Borrup, 2015). Progenitors are “people who feel a sense of attachment to a neighborhood such as those who live, work, and operate small businesses there…often active in and integral to the formation of cultural districts and to the identity the community adopts” (Borrup, 2015). Based on Borrup’s definition of progenitors, this paper will identify residents, small businesses, property owners, non-profits and artists as progenitors of a community.
114

Polynomial Expansion-Based Displacement Calculation on FPGA / Polynomexpansions-baserad förskjutningsberäkning på FPGA

Ehrenstråhle, Carl January 2016 (has links)
This thesis implements a system for calculating the displacement between two consecutive video frames. The displacement is calculated using a polynomial expansion-based algorithm. A unit tested bottoms-up approach is successfully used to design and implement the system. The designed and implemented system is thoroughly elaborated upon. The chosen algorithm and its computational details are presented to provide context to the implemented system. Some of the major issues and their impact on the system are discussed.
115

Confronting the juggernaut of extraction : local, national and transnational mobilisation against the Phulbari coal mine in Bangladesh

Luthfa, Samina January 2012 (has links)
A massive open-cast coal mine was proposed for Phulbari in 1994, with the support of the government and international financial organisations. Threatened by displacement, the apparently powerless community mobilised against the mine. Allied with the national and the transnational activist organisations, they successfully stopped the mine. This remarkable success is the subject of the thesis. This resistance is compared quantitatively with the incidence of protests in 397 other mines in the South Asia. Predictors of protest include density of population, proportion of area under forest cover, and ownership by a multinational company. These factors alone would predict a high probability of protest in Phulbari. To understand how the resistance unfolded and why it was successful, the thesis relies on ethnographic evidence. I conducted participant observation and interviewed sixty-four individuals in Phulbari and Dhaka in Bangladesh and in London. Mobilisation against the mine can be explained in part by dialogic framing. Local challengers continuously opposed the dominant discourse of development. Crucially, they shifted their identity to legitimize their opposition to the mine by tagging it with nationalism. As a result, local resistance established links with national left-wing activists. Mobilisation culminated in a mass march of 70,000 in 2006, which was fired on by government forces, with several casualties. Repression failed to quail the resistance. Continued mobilisation was motivated by emotional responses like anger, and facilitated by cultural practices like the obligatory funeral procession. Media reports of the repression catapulted the resistance on to the global stage. This alone is not sufficient to explain the formation of a transnational alliance against the mine. This was maintained by the presence of a large community of Bangladeshi living in Britain, and the mediating role of the left-wing activists in Bangladesh; both groups could translate between locals and western NGOs. This transnational coalition impeded the mining company by targeting international financial organisations, Western governments, the government of Bangladesh, and investors in London. As a result, the company’s share price has collapsed and there seems little prospect of the project proceeding.
116

Performance analysis software for reinforced concrete beam-columns under various load and displacement patterns

Rohleder, Schyler January 1900 (has links)
Master of Science / Department of Civil Engineering / Asad Esmaeily / Performance-based building design is a necessity in geographic locations where buildings are susceptible to large earthquakes and high winds. This design method requires an analysis of the performance of the structural system with loadings and deflections caused by earthquakes and wind. Current design codes include the load intensity in analysis procedures, but do not consider the effect of load pattern in the performance analysis of reinforced concrete columns. Because a thorough analysis must take into consideration load pattern and load intensity, computer software is ideal to analyze these systems. A computer program was originally developed by Esmaeily (USC_RC), and was revised later to be renamed (KSU_RC) in order to make the analysis of concrete column performance accurate, yet simple for design purposes. This analytical tool used analytical methods and material models, verified against experimental data, to accurately predict the performance of reinforced concrete columns under various loading conditions, including any pattern in lateral direction and independently variable axial load. However, the program was limited to circular, rectangular, hollow circular and rectangular sections and uniaxial lateral curvature and displacement. The next generation of the program, KSU RC 2.0, was developed to overcome the aforesaid limitations.
117

Experimental studies on pore wetting and displacement of fluid by CO2 in porous media

Li, Xingxun January 2015 (has links)
The study of multiphase flow in porous media is highly relevant to many problems of great scientific importance, such as CO2 storage and enhanced oil recovery. Even though significant progress has been made in these areas, many challenges still remain. For instance, the leakage of stored CO2 may occur due to the capillary trapping failure of cap rock. Approximately 70% of oil cannot be easily recovered from underground, because the oil is held in tight porous rocks. Although CO2 storage and enhanced oil recovery are engineering processes at a geological scale, they are predominantly controlled by the transport and displacement of CO2 and reservoir fluids in aquifers and reservoirs, which are further controlled by wetting and fluid properties at pore scale. This work focuses on experimental investigations of pore-scale wetting and displacement of fluids and CO2 in porous core samples. Pore wetting, which has been measured based on contact angle, is a principal control on multiphase flow through porous media. However, contact angle measurement on other than flat surfaces still remains a challenge. In order to indicate the wetting in a small pore, a new pore contact angle measurement technique is developed in this study to directly measure the contact angles of fluids and CO2 in micron-sized pores. The equilibrium and dynamic contact angles of various liquids are directly measured in single glass capillaries, by studying the effects of surface tension, viscosity and chemical structure. The pore contact angles are compared with the contact angles on a planar substrate. The pore contact angle of a confined liquid in a glass capillary differs from the contact angle measured on a flat glass surface in an open space. Surface tension is not the only dominant factor affecting contact angle. The static contact angle in a glass pore also varies with liquid chemical structure. Viscosity and surface tension can significantly affect the dynamic pore contact angle. A new empirical correlation is developed based on our experimental data to describe dynamic pore wetting. The CO2-fluid contact angle in porous media is an important factor affecting the feasibility of long-term permanent CO2 storage. It determines CO2 flow and distribution in reservoirs or aquifers, and thus ultimately finally the storage capacity. CO2-fluid contact angles were measured in small water-wet pores and oil-wet pores, investigating the effect of CO2 phase (gas/liquid/supercritical). The CO2 phase significantly affects the CO2-fluid contact angle in an oil-wet pore. Supercritical CO2-fluid contact angles are larger than gas CO2-fluid contact angles, but are smaller than liquid CO2-fluid contact angles. However, this significant CO2 phase effect on contact angle was not observed in a water-wet pore. Another key issue considered in this study is two-phase flow displacement in porous media. This strongly relates to the important macroscopic parameters for multiphase flow transport in porous media, such as capillary pressure and relative permeability. Here CO2-water displacements are studied by conducting CO2 flooding experiments in a sandstone core sample, considering the effects of CO2 phase, pressure and CO2 injection rate. The capillary pressure-saturation curve, water production behaviour and relative permeability are investigated for gas CO2-water, liquid CO2-water and supercritical CO2-water displacements in porous media. The pressure-dependant drainage capillary pressures are obtained as a result of CO2-water interfacial tension. Various water production behaviours are obtained for gas CO2-water and liquid CO2-water displacements, mainly due to the effect of CO2 dissolution. The significant irregular capillary pressure-saturation curves and water production behaviors can be observed for the supercritical CO2-water displacements. The water and CO2 relative permeabilities for CO2-water displacements in a porous media are then predicted.
118

Asylum as reparation

Souter, James January 2014 (has links)
In this thesis, I examine the theoretical and practical implications of understanding asylum as a form of reparation. My basic contention is that offers of asylum potentially constitute a means through which states can discharge their special obligations towards refugees for whose flight they are responsible. Asylum, on my account, is an institution that can contribute to the rectification of the unjustified harms that states may have caused refugees by forcing them to flee. The thesis is divided into three main parts. In Part I, I lay out a basic theory of asylum as reparation, explaining my conception of asylum and its potential moral functions in Chapter 1, and demonstrating the ways in which asylum may act reparatively in Chapter 2. In Part II, I seek to identify the conditions under which states owe asylum as reparation to refugees. Over the following three chapters, I argue that states have such an obligation when they bear outcome responsibility for unjustified harms experienced by refugees as a result of their flight, and when asylum is the most fitting form of reparation for those harms that is available. In Part III, I apply my theory to the case of Iraqi refugees generated since the invasion of Iraq in 2003, and explore some of the practical implications of my approach. In Chapter 6, I argue that the US and UK owe asylum as reparation to large numbers of Iraqi refugees. In Chapter 7, I examine the implications of my approach for domestic asylum politics, questioning how states should prioritise refugees to whom they owe reparation vis-à-vis other refugees, and exploring its potential impact on debates over asylum. In Chapter 8, I identify its implications for the international politics of refugee protection, anticipating some of the incentives that it might create for states.
119

Off the edge

Stoneham, Luke January 2014 (has links)
Work which takes from elsewhere forms an important thread in European art music. There is a long tradition of music which variously borrows, thieves, pastiches, plagiarises, ironically ‘retakes’, hoaxes, impersonates and appropriates. The music I have written for Off the edge, while seeking to honour and add to this thread, also attempts to zoom in upon and make explicit the idea of an ultimate and irreversible composerly self-annihilation, a kind of one-way exit-gate from the world of authored musical works itself made of pieces of music, which so much of this tradition, I feel, points towards. (Of my nine pieces, it is perhaps Time to go—only, with its ‘à la suicide note’ texts and its music that seems to slide in from far beyond the frame that is ‘composer Luke Stoneham’, which manages to get closest to this.) I have chosen the title Off the edge, because all of my music tries to capture a sense of nocturnal peripheral vision: be content with catching glimpses of the composer Luke Stoneham, because as soon as you turn to look at him face-on, he disappears.
120

Estimating the potential returns to research and development from sorghum value added products in El Salvador and Nicaragua

Jaen Celada, Jaeljattin R. January 1900 (has links)
Master of Science / Department of Agricultural Economics / Timothy J. Dalton / Sorghum bicolor (L.) Moench is a drought tolerant crop able to adapt to hot and dry weather. It has excellent chemical and physical properties, which make it a grain of good quality for processing different types of products. This research is an impact assessment study that estimated the potential impacts of new uses of sorghum by using an equilibrium displacement model. The data used was drawn from interviews developed in July 2011. Using total quantity production, prices, prices elasticities and cost shares 8 potential market scenarios were simulated. Results between countries were similar. Thus, the analysis was applied for both countries. Producers gain when the sorghum flour demand is shifted between $6,000 and $ 30,000. When the feed demand curve shifted the producer benefit was between $3 million and $ 13 million. In the scenario where the sorghum grain curve shifted and the demand curve for feed and sorghum flour, producer net benefit is between $300,000 to $2.5 million. Interpreting these results suggest that increasing yield and promoting sorghum as a substitute of maize for feed and sorghum as a substitute of wheat for sorghum flour can benefit producers while helping them to increase yield.

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