Third-order nonlinear optical properties of ruthenium alkynyl complexes

The field of nonlinear optics has expanded rapidly over the last 50 years as these nonlinear optical (NLO) effects are increasing utilised in devices. NLO involves the manipulation of light by as it travels through a material, which has the potential to be used in all optical data processing as well as intensity dependent imaging. These applications demand new materials with large nonlinear optical properties, of which organometallics and metal coordination complexes have a good reputation. Organometallics, especially ruthenium alkynyl complexes permit many different structural alterations which result in linear and nonlinear optical property tuning allowing for precise design of materials, however understanding of the structure-property relationships is imperative for such design. In this work, complexes with a systematically varied structure have been had their third order nonlinear optical properties analysed utilising the Z-scan technique covering a broad wavelength range; the nonlinear absorptive properties being of particular interest. Comparison of these results allows for determination of structural moieties that give high NLO response. Ruthenium alkynyl dendrimers have considerable nonlinear absorptive properties and the second part of this work covers the modification of the core structure to assess its potential for inclusion into larger systems. The level of core substitution (the number of arms branching from the core) and even the core symmetry influences the electronic properties of the molecule and therefore the nonlinear optical properties. The design limitations and synthesis of ruthenium alkynyl complexes with twelve different core substitutions is detailed and the optical and nonlinear optical properties discussed

Website​ ​Resource​ ​For​ ​Strengthening​ ​The​ ​Relationships​ ​Of​ ​Fathers And​ ​Their​ ​Children​ ​To​ ​Increase​ ​Academic​ ​Achievement

The research question addressed in this project is, how can empowering fathers in their child’s life increase student academic achievement? The Capstone provides literature supporting the value of father in the lives of their children, providing them with optimal success in academics and beyond the classroom. It brings together characteristics and statistics of fatherhood, detailing how a father impacts: family roles, child’s behavior, child’s needs, learning tasks, daughters, a child with special needs, mother and father differences, and early child development. The author brings forth research to support fathers staying engaged with their child, from before birth to adolescence, providing positive learning experiences supporting their child’s social, emotional and cognitive development. A website was created to synthesize the research and provide meaningful learning activities to support fathers and their child’s academic success. The learning opportunities are hands on, engaging and have a focus in the areas of math, literacy and science

The Creation, Validation, and Application of Synthetic Power Grids

Public test cases representing large electric power systems at a high level of fidelity and quality are few to non-existent, despite the potential value such cases would have to the power systems research community. Legitimate concern for the security of large, high-voltage power grids has led to tight restrictions on accessing actual critical infrastructure data. To encourage and support innovation, synthetic electric grids are fictional, designed systems that mimic the complexity of actual electric grids but contain no confidential information. Synthetic grid design is driven by the requirement to match wide variety of metrics derived from statistics of actual grids. The creation approach presented here is a four-stage process which mimics actual power system planning. First, substations are geo-located and internally configured from seed public data on generators and population. The substation placement uses a modified hierarchical clustering to match a realistic distribution of load and generation substations, and the same technique is also used to assign nominal voltage levels to the substations. With buses and transformers built, the next stage constructs a network of transmission lines at each nominal voltage level to connect the synthetic substations with a transmission grid. The transmission planning stage uses a heuristic inspired by simulated annealing to balance the objectives associated with both geographic constraints and contingency reliability, using a linearized dc power flow sensitivity. In order to scale these systems to tens of thousands of buses, robust reactive power planning is needed as a third stage, accounting for power flow convergence issues. The iterative algorithm presented here supplements a synthetic transmission network that has been validated by a dc power flow with a realistic set of voltage control devices to meet a specified voltage profile, even with the constraints of difficult power flow convergence for large systems. Validation of the created synthetic grids is crucial to establishing their legitimacy for engineering research. The statistical analysis presented in this dissertation is based on actual grid data obtained from the three major North American interconnects. Metrics are defined and examined for system proportions and structure, element parameters, and complex network graph theory properties. Several example synthetic grids are shown as examples in this dissertation, up to 100,000 buses. These datasets are available online. The final part of this dissertation discusses these specific grid examples and extensions associated with synthetic grids, in applying them to geomagnetic disturbances, visualization, and engineering education

Intensity limits of the PSI Injector II cyclotron

We investigate limits on the current of the PSI Injector II high intensity separate-sector isochronous cyclotron, in its present configuration and after a proposed upgrade. Accelerator Driven Subcritical Reactors, neutron and neutrino experiments, and medical isotope production all benefit from increases in current, even at the ~ 10% level: the PSI cyclotrons provide relevant experience. As space charge dominates at low beam energy, the injector is critical. Understanding space charge effects and halo formation through detailed numerical modelling gives clues on how to maximise the extracted current. Simulation of a space-charge dominated low energy high intensity (9.5 mA DC) machine, with a complex collimator set up in the central region shaping the bunch, is not trivial. We use the OPAL code, a tool for charged-particle optics calculations in large accelerator structures and beam lines, including 3D space charge. We have a precise model of the present production) Injector II, operating at 2.2 mA current. A simple model of the proposed future (upgraded) configuration of the cyclotron is also investigated. We estimate intensity limits based on the developed models, supported by fitted scaling laws and measurements. We have been able to perform more detailed analysis of the bunch parameters and halo development than any previous study. Optimisation techniques enable better matching of the simulation set-up with Injector II parameters and measurements. We show that in the production configuration the beam current scales to the power of three with the beam size. However, at higher intensities, 4th power scaling is a better fit, setting the limit of approximately 3 mA. Currents of over 5 mA, higher than have been achieved to date, can be produced if the collimation scheme is adjusted

Restoration of Isotropy for Spin Models

Using real-space renormalisation techniques we analyse the Ising model on a Sierpi\'nski gasket with anisotropic microscopic couplings, and observe a restoration of isotropy on macroscopic scales. In particular, via use of a decimation procedure directly on the fractal lattice, we calculate explicitly the exponential anisotropy decay coefficients near the isotropic regime for both ferromagnetic and antiferromagnetic systems. The results suggest the universality of the phenomenon in lattice field theories on fractals.Comment: 10 pages, RevTeX, 4 postscript figures, to appear in Phys. Lett.

Modeling Tiger Population and Territory Dynamics Using an Agent-Based Approach

Effective conservation planning of globally endangered tigers (Panthera tigris) requires a good understanding of their population dynamics. Territoriality, an essential characteristic of many wildlife species, plays a crucial role in the population dynamics of tigers. However, previous models of tiger population dynamics have not adequately incorporated territoriality. We therefore developed and implemented a spatially explicit agent-based model of tiger population dynamics shaped by different territorial behaviors of males and females. To allow for predictions to new conditions, for which no data exist, territories are not imposed but emerge from the tigers’ perception of habitat quality and from their interactions with each other. Tiger population dynamics is deduced from merging territory dynamics with observed demographic rates. We apply the model to Nepal’s Chitwan National Park, part of a global biodiversity hotspot and home to a large (∼125) population of tigers. Our model matched closely with observed patterns of the real tiger population in the park, including reproduction, mortality, dispersal, resource selection, male and female land tenure, territory size and spatial distribution, and tiger population size and age structure. The ultimate purpose of the model, which will be presented in follow-up work, is to explore human-tiger interactions and assess threats to tiger populations across contexts and scales. The model can thus be used to better inform decision makers on how to conserve tigers under uncertain and changing future conditions

The Creation, Validation, and Application of Synthetic Power Grids

Public test cases representing large electric power systems at a high level of fidelity and quality are few to non-existent, despite the potential value such cases would have to the power systems research community. Legitimate concern for the security of large, high-voltage power grids has led to tight restrictions on accessing actual critical infrastructure data. To encourage and support innovation, synthetic electric grids are fictional, designed systems that mimic the complexity of actual electric grids but contain no confidential information. Synthetic grid design is driven by the requirement to match wide variety of metrics derived from statistics of actual grids. The creation approach presented here is a four-stage process which mimics actual power system planning. First, substations are geo-located and internally configured from seed public data on generators and population. The substation placement uses a modified hierarchical clustering to match a realistic distribution of load and generation substations, and the same technique is also used to assign nominal voltage levels to the substations. With buses and transformers built, the next stage constructs a network of transmission lines at each nominal voltage level to connect the synthetic substations with a transmission grid. The transmission planning stage uses a heuristic inspired by simulated annealing to balance the objectives associated with both geographic constraints and contingency reliability, using a linearized dc power flow sensitivity. In order to scale these systems to tens of thousands of buses, robust reactive power planning is needed as a third stage, accounting for power flow convergence issues. The iterative algorithm presented here supplements a synthetic transmission network that has been validated by a dc power flow with a realistic set of voltage control devices to meet a specified voltage profile, even with the constraints of difficult power flow convergence for large systems. Validation of the created synthetic grids is crucial to establishing their legitimacy for engineering research. The statistical analysis presented in this dissertation is based on actual grid data obtained from the three major North American interconnects. Metrics are defined and examined for system proportions and structure, element parameters, and complex network graph theory properties. Several example synthetic grids are shown as examples in this dissertation, up to 100,000 buses. These datasets are available online. The final part of this dissertation discusses these specific grid examples and extensions associated with synthetic grids, in applying them to geomagnetic disturbances, visualization, and engineering education

(The good), the bad and the ugly: The visual construction of female child sex offenders

This paper explores the visual construction and representation of female sex offenders. It utilises the case study of Vanessa George, a nursery worker who was involved in the exchange of indecent imagery of children via an online paedophile ring. The first part of the paper considers the emergence of the sub-discipline, visual criminology and examines what is known about the visual representation of female offenders. The second part presents the findings of an empirical investigation, which involved engaging in a critical, reflexive visual analysis of a selection photographs and the police mugshot of Vanessa George. The paper considers the ways in which George‟s physical appearance and her suggested ability to deceive were used to visually represent her as “other”, thus reinforcing the existing simplistic motifs of female sex offending