Mesoscopic devices, such as nano-wires, are of interest for the next step in creating spintronic devices. With the ability to manipulate electrons and their spin, spintronic devices may be realised. To that end the different effects found in low-dimensional devices must be studied and understood. In this thesis  the influence that lateral spin-orbit coupling (LSOC) has on a nanowire, with asymmetrical confinement potential, is studied. The nanowire is studied through a numerical approach, using the Hartree-Fock method with Dirac interactions to solve the eigenvalue problem of an idealised infinite nanowire. The nanowire has a split-gate that generates the electrostatic asymmetrical confinement potential. It is found that the lateral spin-orbit coupling has little to no effect without any longitudinal effects in the wire, such as source-drain bias. The electrons will spontaneously create spin-rows in the device due to spin polarization. The spin polarization is triggered by using LSOC, numerical noise or from a weak magnetic field. / Mesoskopiska anordningar, som nano-trådar, tros vara ett viktigt steg för att skapa spinnelektronik. För att kunna skapa spinnelektronik behövs kunskap om hur elektroner kan manipuleras. Generellt måste därför existerande fenomen i nanoelektronik studeras. I denna avhandling studeras hur ''lateral spin-orbit koppling'' (LSOC) influerar en nanotråd som har en asymmetrisk potentialbarriär. Hartree-Fock metoden, med Dirac potential för elektron-elektron interaktioner, användes för att beräkna energinivåerna för en idealisk, oändligt lång nanotråd. Nanotråden har en split-gate som alstrar den elektrostatiska, asymmetriska potentialbarriären. "Lateral spin-orbit koppling" visar sig ha minimal effekt då longitudinella effekter, exempelvis spänning, saknas. Elektronerna placerar sig spontant i spinn-rader i tråden vid spontan spinn polarisation. Spinn polarisationen sätts igång av LSOC, numeriska störningar eller från svagt pålagt magnetfält.

QC 351 A7 no. 40 / The aim of this study was to determine to what extent a constant spectral response can be obtained for wide-passband interference filters used with wide -angle lenses. We investigated the possibility of using the curvature of the lens surfaces to reduce the shift in the filter passband for large field angles and found that locating the filter on the proper surface will considerably reduce the shift of the passband. Specifically, we determined the distribution of angles of incidence for full aperture pencils incident at several field angles on the second and fourth surfaces of the 90° Geocon IV, the 90° Paxar, and the 125° Pleogon. We then calculated the spectral transmittance of each lens when a wide passband interference filter was located on its second or fourth surface. We also calculated the degree of polarization introduced. From the cases considered, we found that the tracing of an upper and lower marginal (rim) ray at maximum field angle is sufficient to determine the suitability of a surface, the criterion being that, the smaller the angle of incidence at the surface, the better. In addition, we found that, with the filter on the second surface of the Paxar, spectral transmittance changes with field angle were negligible and the modulation due to polarization was about 1 %.

In this thesis, resonance enhanced multiphoton ionisation (REMPI) in combination with time-of-flight mass spectrometry (TOF-MS) has been used to detect nascent photofragments resulting from the UV dissociation of a variety of small molecules. The translational anisotropy and angular momentum polarisation of these photofragments has been measured and used to elucidate the underlying photodissociation dynamics. Firstly, the photodissociation of NO₂ at 320nm has been investigated and the vector correlations of the nascent NO photofragments have been measured in terms of a set of semi-classical bipolar moments. The measured angular momentum alignment is found to be consistent with an impulsive model for the dissociation, with <b>&mu;</b> and <b>&nu;</b> in the same molecular plane and both preferentially perpendicular to <b>J</b>, whilst angular momentum orientation measurements provide evidence for an additional torque due to the O-N-O bond opening during dissociation. These measurements were taken using a rotationally cooled, skimmed molecular beam and significant deviations were found between the bipolar moments measured using this source and previous measurements using a rotationally hotter source. The effect of parent molecular rotations on the measured bipolar moments has been quantified and successfully used to explain these deviations. The photodissociation of Cl₂ has been studied in the wavelength region (320-350)nm. UV absorption in this wavelength region may result in two dissociation channels, (Cl+Cl) and (Cl+Cl*), and the angular momentum polarisation of both the Cl(²P_3/2) and Cl*(²P_1/2) photofragments has been measured. This angular momentum polarisation has been reported in terms of a polarisation parameter formalism which, together with the measured translational anisotropies, has been used to determine the different potential energy surfaces contributing to the dissociation process. Translational anisotropy measurements of the Cl(²P_3/2) fragments have shown that, for the ground-state channel, dissociation results from a pure perpendicular transition to the C state, whilst alignment measurements show that non-adiabatic transitions to the A state are significant at large internuclear separations. The measured alignment parameters are found to be relatively constant for all dissociation wavelengths and are consistent with theoretical predictions. Translational anisotropy measurements of the Cl(2P_1/2) photofragments show that, for the excited-state channel, dissociation occurs following a mixed parallel and perpendicular excitation to the B and C states respectively and the interference between these two dissociation pathways has been shown to result in angular momentum orientation. The predissociation dynamics of the C ³&Pi;_g (&nu;=0) and (&nu;=1) Rydberg states of O₂ has been extensively studied. The translational anisotropy and angular momentum alignment of the O(³P) and O(¹D) photofragments resulting from this predissociation has been measured in terms of a polarisation parameter formalism, which has been extended for a two-photon dissociation process. Measurements have been taken at various fixed wavelengths within the two bands in order to investigate the differences in the predissociation dynamics of intermediate levels with different values of |&Omega;|(=0,1,2 in this case). The translational anisotropy is found to be dependent on the dissociation wavelength with the variations found to be consistent with rotational depolarisation due to the long lifetime of the excited C state. All photofragments have been found to be aligned, with the relationship between the measured O(³P) and O(¹D) alignment being found to be consistent with a diabatic model of the dissociation. In addition, all photofragments are found to display coherent orientation resulting from interference between two possible two-photon absorption pathways. The measured orientation is affected by rotational depolarisation due to the long lifetime of the excited C state; once this effect is accounted for the orientation is found to be nearly constant over all dissociation wavelengths. The origin of the coherent orientation is attributed to two-photon absorption to different spin-orbit components of the C state.

The study of Supernova Remnants (SNRs) is fundamental to understanding the chemical enrichment and magnetism in galaxies, including our own Milky Way. In an effort to understand the connection between the morphology of SNRs and the Galactic Magnetic Field (GMF), we have examined the radio images of all known SNRs in our Galaxy and compiled a large sample that have an axisymmetric morphology, which we define to mean SNRs with a bilateral or barrel-shaped morphology, in addition to one-sided shells. We selected the cleanest examples and model each of these at their appropriate Galactic position using two GMF models, one of which includes a vertical halo component, and another that is oriented entirely parallel to the plane. Since the magnitude and relative orientation of the magnetic field changes with distance from the Sun, we analyze a range of distances, from 0.5 to 10 kpc in each case. Using a physically motivated model of an SNR expanding into an ambient GMF that includes a vertical halo component, we find it is possible to reproduce observed morphologies of many SNRs in our sample. These results strongly support the presence of an off-plane, vertical component to the GMF, and the importance of the Galactic field on SNR morphology. Our approach also provides a potentially new method for determining distances to SNRs, or conversely, distances to features in the large-scale GMF if SNR distances are known. The mechanism for acceleration of cosmic rays in SNRs is another outstanding question in the field. To investigate this, the same sample of axisymmetric SNRs was again modelled, but this time using two competing, and physically motivated, Cosmic Ray Electron (CRE) acceleration cases: quasi-perpendicular and quasi-parallel. We find that the quasi-perpendicular CRE acceleration case is much more consistent with the data than the quasi-parallel CRE acceleration case, with G327.6+14.6 (SN1006) being a notable exception. We propose that SN1006 may be an example of a case where both quasi-parallel and quasi-perpendicular acceleration is simultaneously at play in a single SNR. / October 2016

Corrosion of all aluminum microchannel heat exchangers present a challenge in automotive and heating, ventilation, and air conditioning (HVAC) industries. Reproducibility of Salt Water Acetic Acid Test (SWAAT) has been questioned and a need to new corrosion tests with better reproducibility has risen. Cyclic polarization, that is an electrochemical test, was explored for its suitability for the assessment of AA 3102 tube material that is currently a popular aluminum alloy used in manufacturing of heat exchanger. Corrosive electrolytes containing 3.5 % sodium chloride with 0.5 % ammonium sulfate (high chloride) or 0.5 % sodium chloride with 3.5 % ammonium sulfate (high sulfate) at their pH or acidic (pH=4) were used to measure corrosion potential (Ecorr), protection potential (Epp), pitting potential (Epit), Tafel constants (βa and βc), corrosion rate (mpy). Corrosive electrolyte used in SWAAT test (4.2% Sea Salt at pH 2.9) was also used to compare corrosion resistance of AA 3102 in SWAAT electrolyte compared to the other electrolytes used in this research. Scanning electron microscopy (SEM) was used to observe and document sample surface corrosion damage after each electrochemical test on all samples. Results of the cyclic polarization tests indicated that SWAAT electrolytes was the most aggressive electrolyte resulting in highest corrosion rates compared to all other electrolytes used in this investigation. SEM results indicated AA 3102 alloy exhibited higher pitting tendency in electrolytes with high sodium chloride whereas high sulfate electrolytes cause appearance of uniform corrosion surface damage on this alloy. Both high sulfate and SWAAT electrolytes showed intergranular corrosion but high chloride electrolyte showed severe pitting of AA 3102. Mohammad Navid Dorreyatim- Cyclic Polarization of AA 3102 in Corrosive Electrolytes Containing Sodium Chloride and Ammonium Sulfate. Master of Science (Mechanical and Energy Engineering), December 2016, 98 pp., references, 31 titles.

Graphene, the world's first truly two-dimensional material, is unique for having an electronic structure described by an effective Lorentz invariant theory. One important consequence is that the ratio or Coulomb energy to kinetic energy is a constant, depending only on conditions within the lattice rather than on the average charge density as in a typical Galilean invariant material. Given this unusual property, a natural question would be how do phenomena, such as screening of a Coulomb impurity, happen in graphene? Moreover, how does the addition of uniaxial strain enhance or diminish this behavior? Here I discuss our work to calculate the charge density distribution in a lattice of strained graphene under the effect of an external Coulomb impurity. Graphene can have its band structure significantly altered by the application of uniaxial strain. Two cases are here explored: relatively weak strain at some finite chemical potential, and extreme strain with zero chemical potential. In the first system, the strain induces elliptic Dirac cones, engendering some inherent directionality to graphene's electronic properties that did not exist before. This anisotropy manifests itself in the polarization function, and so too in the screening charge density. A finite chemical potential in this case is necessary for any screening to take place in graphene since, without it, there are no electron states near the Fermi level to polarize. Both in the strained and unstrained case, decaying oscillations known as Friedel oscillations are observed. The result of strain is a multifaceted anisotropy of the charge distribution: the amplitude, frequency, and the position of the first peak in the oscillations are each varied depending on the direction one observes. In the second system, extreme strain in graphene leads to a merging of Dirac cones, yielding a transition to a new energy spectrum. This band structure is unusual in that it becomes quadratic along the direction of strain while remaining linear along the perpendicular. We evaluate the screening response to a Coulomb impurity in this case at zero chemical potential, and yet long-range distribution tails are still observed. The result is a very exotic charge distribution, in which the radial distribution of charge and the angular distribution are highly coupled, and at various distances, both screening and anti-screening regions are observed around the impurity. The anti-screening regions are local, and the net induced charge density still satisfies the accepted model of screening.

A growing body of literature suggests Breast Cancer-Associated Protein 1 (BRCA1) is important not only as a cause, but also as a target in the quest for cancer treatment. BRCA1 deficient cells treated with radiation as well as PARP inhibitors and other chemotherapeutics demonstrate a greater sensitivity than cells with wild type BRCA1. Inhibitors of BRCA1 would take advantage of this synthetic lethality and represent a significant advance in cancer treatment as well as an understanding of the biology of DNA repair. Despite significant study of BRCA1 protein and function, it is a large protein (220 KDa) that is still largely uncharacterized, but its N- and C-terminal domains have been described by significant structural data. The BRCT (BRCA1 C-Terminal) Domain is a phosphoprotein binding domain that is commonly mutated or lost in cancers and has a binding cleft seemingly very suitable for drug design. Small molecule screens have been conducted against this domain, but the resulting hits with moderate affinity have not been shown to induce BRCA1 deficient phenotypes. Phosphopeptides have also been studied as potential BRCA1 inhibitors, yet despite some having affinities in the mid-nanomolar range the presence of a phosphate is not without its pharmacologic challenges. We generated an mRNA display library with 1.3 x 10^13 cyclized peptides covalently attached to the mRNA that encoded them. Eight rounds of selection exposing the library to a GST-BRCT fusion resulted in selection of non-phosphorylated peptides that bind to a BRCT domain of BRCA1. The sequences resulting from the selection have common homologies and initial characterization has shown that these peptides may be the first viable non-phosphoserine containing inhibitors of BRCA1.

Four studies investigated the effects of attitude extremity and political ideology on the degree and direction of changes in issue attitudes following the presentation of mixed evidence. Based upon previous work, it was predicted that those holding relatively more extreme attitudes would resist changing those views when presented with a mixture of supporting and opposing statements and would potentially adopt more extreme evaluative positions – a phenomenon known as attitude polarization (Lord, Ross, & Lepper, 1979). Evaluative entrenchment or intensification was also expected among more politically conservative participants, based upon prior work describing cognitive rigidity and resistance to change as more characteristic of the political right than left (e.g., Jost, Glaser, Kruglanski, & Sulloway, 2003). An interaction of attitude extremity and political ideology was also hypothesized, such that liberal individuals with moderate attitudes were expected to demonstrate the least propensity to polarize. Participants’ attitudes regarding abortion rights (Study 1), gun control (Study 2), tax increases (Study 3), and environmental preservation (Study 4) were assessed before and after reading statements that both opposed and supported the issue. Political ideology was also assessed, along with several individual difference factors. Across all four studies, attitude extremity significantly predicted evaluative change, although the pattern of that effect varied. Political ideology did not emerge consistently as a predictor of attitude change; however, significant interactive effects of extremity and ideology were found. In addition, several individual difference factors (i.e., gender, need for cognition, issue importance) were found to moderate the effects of the primary predictors on attitude change, and some divergent result patterns were found when comparing data from a college and non-college sample in Study 4. Taken together, these studies provide evidence that attitude extremity and political ideology influence the degree and direction of evaluative change following the presentation of mixed evidence. In addition, they identify other factors at work in effecting change versus resistance, thereby highlighting the multi-faceted and complex nature of persuasion in a political context.

The purpose of this study was to assess the impact of acquiescence on both positively and negatively worded questions, both when unidimensionality was assumed and when it was not. To accomplish this, undergraduate student responses to a previously validated survey of student engagement were used to compare several models of acquiescence, using a priori goodness-offit statistics as evidence for model fit, in order to develop a model that adequately accounted for acquiescence bias. Using a true experimental design, undergraduate students from a variety of classes at a large, urban university were randomly assigned to one of three versions of the same survey of student engagement (all positively worded items, all negatively worded items, an equal balance of both positively and negatively worded items). Structural equation modeling was used to analyze the results. Although the presence of acquiescence was confirmed for both positively and negatively worded items, it was not consistent by content scale or item polarization. This suggests that there may be an interaction between item polarization and content that may cause acquiescence to be present or absent. The scales that did not show acquiescence on the balanced survey portrayed a split factor loading based upon item polarization. Further, the splitting of factor loadings by item polarization was not due to acquiescence, suggesting that something other than acquiescence is causing the loadings to split. Further research is needed to develop models and/or methods to better assess and control for acquiescence. Although demographic groups were compared by gender and race/ethnicity to assess if different groups acquiesced differently, using multi-group confirmatory factor analysis, many of the models did not converge. The findings of this study were limited by the nature of the sample size. Additional research is needed to determine if acquiescence differs by group membership.

The European Union is often criticized for having a democratic deficit, and most often cited are the shortcomings in citizen inputs. The complex institutional structure, in particular the dual channel of representation (supranational and intergovernmental), contributes to these concerns. This thesis thus examines what impacts the linkage between citizens and their elected representatives in the direct channel of representation. I refer to this linkage as the "electoral connection" and outline three related input criteria: Competent Citizens: Citizens can competently assign policy responsibility and hold their representatives to account; Meaningful Choices: Citizens have meaningful choices at election time; and Substantive Representation: Elected officials are representative of their constituents. The theoretical framework of the electoral connection is based in substantive representation, and focuses on the mandate conception of representation but also includes a discussion of accountability. I utilize European Election Studies (EES) voter, media, and candidate studies from 2009, EES voter and candidate studies from 1994, and a novel expert survey on EU responsibility (2010). The analyses of responsibility attributions and vote choice are conducted using multilevel modelling to assess individual- and contextual-level determinants. I test the effect that information and political attitudes, specifically extreme attitudes have on the first two criteria of the direct electoral connection. The role of information is tested at the individual level through political sophistication, and at the contextual level through the politicization of the EU issue. The first criterion is tested by comparing citizen and expert attributions of responsibility. For the second criterion, two chapters which examine perceived party positions and issue-cross pressure assess how this impacts the electoral connection. The final empirical chapter is a descriptive analysis of congruence on policy priorities and preference for governmental responsibility to assess substantive representation. If there is some understanding of responsibility, and citizens have selected parties that align with their preferred policy positions, then we should expect government to be representative of its constituents. One contribution is defining an expanded definition of the electoral connection. In addition I show that political sophistication and issue politicization have a positive impact on the electoral connection, while attitude extremity generally has a negative impact. Furthermore, the European Parliament is quite representative of its constituents. Concerns about democratic deficit and lack of representation in the European Union are overstated.