Fast Calculation of the Radiative Opacity of Plasma

Plasma opacity calculations play an important role in solar modelling and many plasma physics and inertial confinement fusion experiments. This thesis is focussed on the fast calculation of opacity from first principles. The existing average atom (AA) opacity code IMP [1] is used alongside experimental data and detailed atomic physics to develop new models; the results show that simple models can give an excellent description of plasma spectra for a large range of conditions. The results are significant for the development of fast opacity codes which necessarily use the AA approach. The application of fast models to very large scale calculations is considered and an efficient approach to these developed; this allows the fast description of experimental data that would not have otherwise been possible [2]. Analysis of this data then allows the accuracy of the IMP model to be further discussed. The atomic model is also considered, and an improved approach implemented. These improvements makes little difference to the description of experiment provided electron exchange is included. The range of applicability of the IMP model is then extended to higher density by adding a fast description of line broadening by electrons. This gives an excellent agreement with both experiment and more advanced opacity codes. The treatment of atomic term structure can represent a significant portion of code runtime. A good compromise between detail and efficiency is the unresolved transition array (UTA) formulation; a consistent theory of UTAs is developed, and various models introduced. The accuracy of these is systematically tested. It is found that within the validity range of the UTA approach, a good description of the opacity can be gained using a simple model provided that the linewidth is correct. Various simplified calculations of this width are tested, and found to be inaccurate [3]

Unravelling the economic and environmental tradeoffs of reducing sediment movement from grazed pastures

An undesirable consequence of grazing activities in eastern Australia is the quantity of sediment emptying into the Great Barrier Reef Lagoon. One of the challenges to reducing sediment loads stems from the lack of private incentives to improve land management practices. There is also a poor understanding of the financial implications resulting from the adoption of sustainable management practices, and, in particular the lack of scientific and economic knowledge linking on-farm management actions to catchment scale impacts. Bio-economic modelling has been used to identify the economic and environmental trade-offs encountered when grazing strategies are altered to reduce off-farm sediment movement from a black spear grass pasture in central Queensland.bioeconomic modelling, grazing, economic and environmental, Environmental Economics and Policy,

The effects of values-clarification strategies on school attitudes in seventh grade English

Educational systems are constantly faced with the question What should students be taught? Traditionally, the answer has been skills and concepts in basic subject areas used most often in life. Consequently, curricula center around facts about these subject areas, skills used by people in these areas, and concepts on which the subjects are based. New ways of presenting facts, skills, and concepts are continually being explored in the hope that students will internalize and apply them when the need arises. Student and parent involvement in the learning process, individualized instruction, high interest learning media, and various groupings of students in learning situations all have but one goal: the acquisition of facts, skills, and concepts by the student

Morality

The Qur’an asks human beings to establish a just social order and to create morally upright individuals. The obligation to act morally arises from human obligation to repay it’s debt to the Creator. Verse 7:172 in the Qur’an indicates that human beings had not only accepted to obey God’s dictates in a primordial covenant but also suggests that they agreed to behave in a morally responsible manner. Because they are moral agents, human beings are free to choose between virtue or vice. Download full text to read more.https://ir.stthomas.edu/encounteringislam/1018/thumbnail.jp

Cost allocation in investment arbitration: Forward toward incentivization

Vasani and Ugale suggested that, from a claimant’s perspective, “the traditional approach encourages arbitration” while “CFtE is largely a deterrent” to investment treaty arbitration and “makes arbitration less appealing to claimants (and would-be third-party funders), more risky and/or outright economically unviable.” 2 They concluded that “a default CFtE custom in the context of ICSID seems inapposite just at a time when [CFtE] appears to be gaining popularity”3 and argue that a harmonized approach to cost allocation between ICSID and commercial forums is likely inappropriate. While we welcome that the authors have initiated a renewed debate on this issue, and note that they raise a range of other objections to CFtE in the context of ICSID, we disagree with their criticism of CFtE as a deterrent to claimants. We suggest that CFtE incentivises meritorious claims while discouraging frivolous or weak claims.

Exploration of new routes to boranes and carboranes

The crystal chemistry of binary metal borides in the composition range M(_4) to MB(_12) and the hydrolytic chemistry of reactive metal borides to give boranes are reviewed. The thermal interconversion reactions of the smaller volatile boranes from B(_2)H(_6) to B(_10)H(_14) is critically examined and a rationalisation of their reactions with the transient Lewis acid species {BH(_3)), (B(_3)H(_7)) and (B(_4)H(_8)) is developed. This approach reveals a pattern of step-wise cage-growth for nido boranes which first seem to ligate a BH(_3) unit and then eliminate H(_2) giving the next higher homologue. Also, a structure-reactivity relationship for B(_2)H(_6) and the arachno boranes is suggested where the terminal hydrogens of the BH(_2) groups are thought to possess hydridic character which dominates their reactions with the Lewis acid intermediates. This work is partially extended to the cage-expansion and pyrolysis reactions of the anionic boron hydrides. A detailed review is presented of the pyrolysis of tetraalkylammonium borohydrides to give [B(_10)H(_10)](^2-) and [B(_12)H(_12)](^2-) in high yield. A study of the acidic hydrolysis of MgB(_2) under a wide range of conditions is reported. The reactions of MgB(_2) with 100% H(_3)PO(_4) and with 7M H(_3)PO(_4) under the influence of ultrasonics are found to be promising methods for increasing the borane yield. The anions [B(_12)H(_120](^2-), [B(_10)H(_10)](_2) and possibly [B(_9)H(_14)](^-) are shown to be important products from MgB(_2) hydrolysis. A mechanism is proposed for this reaction incorporating initial production of CB(_6)H(_9)](^-) which is protonated to give B(_6)H(_10); degradation of this borane in the acidic solution is thought to account for generation of B(_5)H(_9) and B(_4)H(_10) which are the only other major volatile boron hydride products. Finally, some attempted "one-pot” carborane syntheses using MgB(_2) as the boron source are discussed

Change is good: adapting strategies for archaeological prospection in a rapidly changing technological world

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Near-field sound radiation of fan tones from an installed turbofan aero-engine

The development of a distributed source model to predict fan tone noise levels of an installed turbofan aero-engine is reported. The key objective is to examine a canonical problem: how to predict the pressure field due to a distributed source located near an infinite, rigid cylinder. This canonical problem is a simple representation of an installed turbofan, where the distributed source is based on the pressure pattern generated by a spinning duct mode, and the rigid cylinder represents an aircraft fuselage. The radiation of fan tones can be modelled in terms of spinning modes. In this analysis, based on duct modes, theoretical expressions for the near-field acoustic pressures on the cylinder, or at the same locations without the cylinder, have been formulated. Simulations of the near-field acoustic pressures are compared against measurements obtained from a fan rig test. Also, the installation effect is quantified by calculating the difference in the sound pressure levels with and without the adjacent cylindrical fuselage. Results are shown for the blade passing frequency fan tone radiated at a supersonic fan operating conditio

Law

Christian understanding of law, as of many other social institutions, derives from both biblical and classical sources. In its broadest sense, the term law is applied to all regularities of behavior, including predictable sequences of events in the natural world, as in modern reference to more or less scientific laws such as universal gravitation or supply and demand. Download full text to read more.https://ir.stthomas.edu/encounteringislam/1015/thumbnail.jp