Poly (Lauryl Methacrylate): spread monolayers and bulk configuration

Deuterated variations of poIy(lauryl methacrylate) (PLMA) have been synthesised, this involved the initial synthesis of the monomer (LMA). This was achieved by a transesterification reaction between methyl methacrylate and lauryl alcohol using either hydrogenous or deuterated materials depending on which part of the resulting LMA monomer was to be deuterated. The physical properties of PLMA and LMA spread monolayers have been investigated using surface pressure - area isotherms and surface quasi - elastic light scattering (SQELS). The isotherms for PLMA show that the thermodynamic state of the polymer is poorer than theta conditions and no variation occurs with changes in temperature. LMA shows a drastic change in the nature of the isotherm as the temperature is varied. This has been attributed to the formation of lenses and the variation caused by temperature is due to a change in the rate of migration of the LMA molecules. The SQELS results show that the PLMA monolayer displays the characteristics of a Voigt solid model and shows no viscous relaxation processes. SQELS has also been used to demonstrate the biphasic nature of the monolayer at low surface concentrations, the size of the polymer 'islands' has been estimated to be in the range of 5 to 20mm. SQELS from LMA monolayers showed that the two higher surface concentrations gradually converted into the same state as that obtained for the lo

The History and Architecture of Petra

Petra was a city of wealth, prosperity, and enormous ingenuity that allowed the Nabataean people to settle and even thrive in one of the harshest environments on earth. The city became the center of trade between the Middle East and the Roman Empire, which brought both wealth and power to its people. It also provided the resources for the construction of staggering tombs, monuments, and cities that turned the desert into an oasis. In addition, the confluence of cultures created the unique Nabataean art style, which incorporated some of the greatest elements of architecture from all over the ancient world and has left an unmistakable mark on the harsh desert landscape. Faculty mentor: Dr. Allison Smit

Impact of the Three Gorges Dam

The Three Gorges Dam was built to provide hydroelectric power, flood control, and greater navigation access to the Yangtze River in central China. It is the largest hydroelectric dam in the world and as such is responsible for bringing both unprecedented benefits and risks to the people of the Yangtze River Valley and all of China. In some cases the dam has been the cause of great devastation including the destruction of both the environment and rich cultural heritage of the Yangtze River valley, but it has also spurred a greater concern for the protection and conservation of both the environment and the way of life for many of the Chinese people. While many of the consequences of the dam will not be felt for many years, both the Chinese and the world will be looking to the dam as an example of the future feasibility of hydroelectric power. This paper analyzes the drawbacks of constructing such an enormous dam as well as the benefits

Simulations of MHD Instabilities in Intracluster Medium Including Anisotropic Thermal Conduction

We perform a suite of simulations of cooling cores in clusters of galaxies in order to investigate the effect of the recently discovered heat flux buoyancy instability (HBI) on the evolution of cores. Our models follow the 3-dimensional magnetohydrodynamics (MHD) of cooling cluster cores and capture the effects of anisotropic heat conduction along the lines of magnetic field, but do not account for the cosmological setting of clusters or the presence of AGN. Our model clusters can be divided into three groups according to their final thermodynamical state: catastrophically collapsing cores, isothermal cores, and an intermediate group whose final state is determined by the initial configuration of magnetic field. Modeled cores that are reminiscent of real cluster cores show evolution towards thermal collapse on a time scale which is prolonged by a factor of ~2-10 compared with the zero-conduction cases. The principal effect of the HBI is to re-orient field lines to be perpendicular to the temperature gradient. Once the field has been wrapped up onto spherical surfaces surrounding the core, the core is insulated from further conductive heating (with the effective thermal conduction suppressed to less than 1/100th of the Spitzer value) and proceeds to collapse. We speculate that, in real clusters, the central AGN and possibly mergers play the role of "stirrers," periodically disrupting the azimuthal field structure and allowing thermal conduction to sporadically heat the core.Comment: 16 pages, 3 tables, 17 figures, accepted to ApJ with minor revisions, to appear in Volume 704, Oct 20, 2009 issu

Relational positionality and a learning disposition: Shifting the conversation

In the complex and diverse region of Oceania, researchers often work across more than one cultural understanding. Thus, a researcher’s position with regard to their research requires careful ongoing negotiation because position, when understood through relationality, is fluid. Negotiating position requires acute reflexivity of the researcher but also offers opportunities for ongoing development and agency. In this article, we use the literature of relational positionality and autoethnographic methodology to discuss two researchers’ deliberate re-positioning in relation to their field of education, focusing on deliberate self-change and the application of new conceptual learning. The context is Pasifika education, a space which sits between different knowledge systems as the education of Pacific-origin people in Aotearoa New Zealand. The article demonstrates how storying can support new understandings which, in turn, can help negotiate positionality. The argument draws on data from a conference tok stori session that illustrates the potential of storying to expose, re-value and then reweave positionality through relational activity.In the complex and diverse region of Oceania, researchers often work across more than one cultural understanding. Thus, a researcher’s position with regard to their research requires careful ongoing negotiation because position, when understood through relationality, is fluid. Negotiating position requires acute reflexivity of the researcher but also offers opportunities for ongoing development and agency. In this article, we use the literature of relational positionality and autoethnographic methodology to discuss two researchers’ deliberate re-positioning in relation to their field of education, focusing on deliberate self-change and the application of new conceptual learning. The context is Pasifika education, a space which sits between different knowledge systems as the education of Pacific-origin people in Aotearoa New Zealand. The article demonstrates how storying can support new understandings which, in turn, can help negotiate positionality. The argument draws on data from a conference tok stori session that illustrates the potential of storying to expose, re-value and then reweave positionality through relational activity

Fifty years on . . .

(ii) development o

Validating the OPA Cascading Blackout Model on a 19402 Bus Transmission Network with Both Mesh and Tree Structures

The OPA model calculates the long-term risk of cascading blackouts by simulating cascading outages and the slow process of network upgrade in response to blackouts. We validate OPA on a detailed 19402 bus network model of the Western Electricity Coordinating Council (WECC) interconnection with publicly available data. To do this, we examine scalings on a series of WECC interconnection models with increasing detail. The most detailed, 19402 bus network has more tree structures at the edges of the main mesh structure, and we extend the OPA model to account for this. The higher-risk cascading outages are the large cascades that extend across interconnections, so validating cascading models on large networks is crucial to understanding how the real grid behaves. Finally, exploring networks with mixed mesh and tree like structure has implications for the risk analysis for both the transmission grid and other network infrastructures

The interplay of network structure and dispatch solutions in power grid cascading failures

For a given minimum cost of the electricity dispatch, multiple equivalent dispatch solutions may exist. We explore the sensitivity of networks to these dispatch solutions and their impact on the vulnerability of the network to cascading failure blackouts. It is shown that, depending on the heterogeneity of the network structure, the blackout statistics can be sensitive to the dispatch solution chosen, with the clustering coefficient of the network being a key ingredient. We also investigate mechanisms or configurations that decrease discrepancies that can occur between the different dispatch solutions

The Impact of Local Power Balance and Link Reliability on Blackout Risk in Heterogeneous Power Transmission Grids

Many critical infrastructures such as the power transmission grid are heterogeneous both in their basic structure and in some of their underlying characteristics, This heterogeneity can be good for system robustness if it reduces the spread of failures or bad if it adds risk or vulnerability to the system. In this paper we investigate the effect of heterogeneity in the strength of the links between parts of the system network structures, as well as the balance of local generation and demand, on the robustness of the power transmission grid using the OPA complex system model of the power transmission system. It is found that increasing or decreasing the reliability of the links between parts of the grid changes the likelihood of different size failures with neither being optimal for all sizes. Furthermore, imbalances between load and generation in the local regions further degrades the system reliability