Load Reduction Using Rapidly Deployed Trailing-Edge Flaps

This thesis details investigations into the aerodynamic properties of a small, rapidlyactuated, actively controlled trailing-edge ap and the potential of such a device to alleviate the unsteady loading experienced by wind turbine blades due to atmospheric turbulence and the atmospheric boundary layer, although such a device would have potential applications in other elds such as rotorcraft. The main goals of this work were to investigate whether aerodynamic loadings could in fact be alleviated by the use of a small trailing-edge ap using only measurements of the unsteady lift on the wing as a control input and to assess such a device's capacity to reject atmospheric disturbances with both numerical and experimental work, carried out in the Aeronautics Department at Imperial College London. The numerical work covered in the thesis comprises the results of linear and nonlinear aerodynamic and control simulations (e.g. PID, LQG controllers) and the results of computational uid dynamics (CFD) simulations using the commercial package FLUENT. The thesis also lays out the results obtained from testing an experimental prototype in the Hydrodynamics Laboratory in the Aeronautics Department. This prototype successfully rejected intentionally introduced ow disturbances from the vortex street of a square block upstream of the wing and the application of control provided a very signi cant reduction in the unsteady loading experienced by the wing. The ndings show the potential of this method of load control for the rejection of unsteady aerodynamic loading by the sole use of measurements of the wing loading and this has been demonstrated both theoretically and experimentally. The work is closed with a conclusion and suggestions for future research proposals

The Potential Applications of Optical Dating to the Sandy Uplands of East Texas and Northwest Louisiana

The fine, sandy soils of East Texas and Northwest Louisiana have been the source of archaeological debate for some time. This discourse concerns the mode of burial of cultural material in the easily eroded soils and the mechanics of recent (Holocene) landform evolution. Because these deposits are typically well-drained, organic matter does not preserve well, thus hindering the dating of the geomorphic events that figure prominently in their development and the prehistoric occupations which lie buried throughout uplands of this region. A relatively new dating technique, optical dating, has much to offer this region and the archaeological community as it measures the period of time that has elapsed since sand grains were last exposed to sunlight. Hence, it directly dates the time of sediment transportation and deposition. This method is therefore applicable to a number of archaeological and geomorphic processes which may not be dated by traditional methods, owing to the lack of organic matter suitable for radiocarbon dating. In geomorphic contexts, optical dating may be preferred over radiocarbon as it directly dates the time of sedimentation rather than the age of organic matter in features such as buried soils that may be significantly different from the geomorphic event which fossilized the soil

Evidence for A Parsec-scale Jet from The Galactic Center Black Hole: Interaction with Local Gas

Despite strong physical reasons that they should exist and decades of search, jets from the Galactic Center Black Hole, Sgr A*, have not yet been convincingly detected. Based on high-resolution Very Large Array images and ultra-deep imaging-spectroscopic data produced by the Chandra X-ray Observatory, we report new evidence for the existence of a parsec-scale jet from Sgr A*, by associating a linear feature G359.944-0.052, previously identified in X-ray images of the Galactic Center, with a radio shock front on the Eastern Arm of the Sgr A West HII region. We show that the shock front can be explained in terms of the impact of a jet having a sharp momentum peak along the Galaxy's rotation axis, whereas G359.944-0.052, a quasi-steady feature with a power-law spectrum, can be understood as synchrotron radiation from shock-induced ultrarelativistic electrons cooling in a finite post-shock region downstream along the jet path. Several interesting implications of the jet properties are discussed.Comment: 33 pages, 7 figures; Accepted for publication in The Astrophysical Journa

An Originalist Defense of Substantive Due Process: Magna Carta, Higher-Law Constitutionalism, and the Fifth Amendment

A longstanding scholarly consensus holds that the Due Process Clause of the FifthAmendment protects only rights to legal process. Both this consensus and the occasional challenges to it have generally overlooked the interpretive significance of the classical natural law tradition that made substantive due process textually coherent, andthe emergence of public-meaning originalism as the dominant approach to constitutional interpretation. This Article fills those gaps. One widely shared understanding of the Due Process Clause in the late eighteenth century encompassed judicial recognition of unenumerated substantive rights as a limit on congressional power. This concept of substantive due process originated in Sir Edward Coke\u27s notion of a higher-law constitutionalism that understood natural and customary rights as limits on crown prerogatives and parliamentary lawmaking. The American colonies adopted higher-law constitutionalism in their revolutionary struggle, and carried it with them through independence and constitutional ratification. Natural and customary rights limited the exercise of legislative power in the late eighteenth century through the normative definition of law inherited from the classical natural law tradition, which maintained that an unjust law was not really a law. American judges and attorneys did not consider legislative acts that violated natural or customary rights to be real laws, regardless of their compliance with a positivist rule of recognition. Accordingly, deprivations of life, liberty, or property effected on the authority of such acts did not comply with the law of the land or the due process of law, because regardless of the process such acts afforded, the deprivations they imposed were not accomplished by a true law. The classical understanding of law and thesubstantive understanding of due process that it underwrote are evident in legal dictionaries and in judicial decisions and arguments of counsel during the years immediately before and after ratification of the Bill of Rights in 1791. On balance, these authorities show that one widely held public understanding of Fifth Amendment Due Process Clause in the late eighteenth century included judicial protection of unenumerated substantive rights against congressional encroachment. Given the contemporary dominance of originalist theories of interpretation, anoriginalist defense of substantive due process under the Fifth Amendment is important for at least three reasons. First, such a defense provides a textual footing for important unenumerated substantive rights against the federal government. Second, because the original meanings of the Fifth and Fourteenth Amendment Due Process Clauses are widely thought to be identical, the originalist defense dramatically alters the interpretive landscape surrounding Fourteenth Amendment substantive due process, placing on its opponents the burden of explaining how and why the substantive understanding of due process in 1791 was lost by 1868. Finally, an originalist defense of substantive due process demonstrates that originalism is consistent with the progressive, common law recognition of individual rights

True Lies: Canossa as Myth

This essay is a response to Paul Horwitz, “Freedom of the Church without Romance,” published as part of a symposium on “The Freedom of the Church.” The essay endorses Horwitz’s central thesis that advocates of a contemporary “freedom of the Church” have overlooked historical complexities in marking the 11th-century investiture conflict between Henry IV and Pope Gregory VII, often simply referred to “Canossa” after the small Emilian village where Henry sought absolution from Gregory, as the birth of that freedom. The essay goes beyond Horwitz to argue that the historical account of “Canossa” presupposed by freedom-of-the-Church advocates is literally false. “Canossa,” instead, is a myth. More salient, nonmythical analogies for a “freedom of the Church” exist in U.S. constitutional history: genuine state sovereignty and dual-sovereignty federalism from the 19th century, and state dignity and native American domestic dependency from the contemporary era. These more historically accessible analogies all suggest that any “freedom of the Church” in U.S. constitutional doctrine is greatly diminished from the robust freedom argued for by those who invoke “Canossa” as that freedom’s defining moment. But even the mythical “Canossa” remains important. Myths are stories that a society tells about itself, stories that preserve and clarify its deepest values and commitments. Like the “myth of Magna Carta” that has exerted so much influence on English and American constitutional law, “Canossa” emphasizes the dangers to liberty from a government that sees no bounds on its jurisdiction and authority. Though historically false, “Canossa” might be mythically true

Public Life and Hostility to Religion

Many who value the contributions of religion to American life have contended that American public life is hostile to religion. They perceive many of the Supreme Court\u27s Religion Clause opinions as hostile to religion, and circulate anecdotes about the antireligious hostility of public life. Studies also suggest that some of the principle actors in American public life systematically marginalize religious viewpoints relative to secular ones. Nevertheless, others are baffled by the suggestion that public life discriminates against religion. These people note that religion is deeply (if controversially) involved in much of contemporary American politics, and dismiss anecdotes about such hostility as isolated instances of departure from a rule of religious accommodation in public life. This Essay seeks to demonstrate in a more precise way how American public life is hostile to religion. Like so much else, the hostility of public life to religion can be traced to one of the conceptual foundations of liberal political theory: the distinction between the public and the private. The Essay begins with a sketch of this distinction in American liberal thought, noting that the public is generally privileged over the private. The Essay argues that, because knowledge is associated with public life and belief with private life, both the distinction between knowledge and belief and the predominance of the former over the latter are assumed rather than demonstrated. It illustrates this thesis with an analysis of two Supreme Court decisions, Aguillard v. Edwards, a creation science decision, and Employment Division v. Smith, a decision about religious exemptions. The Essay closes with some observations about the significance of recognizing that American public life is hostile to belief

Indeterminacy and the Establishment Clause

Part of Symposium: Establishment and Fairnes

True Lies: Canossa as Myth

This essay is a response to Paul Horwitz, “Freedom of the Church without Romance,” published as part of a symposium on “The Freedom of the Church.” The essay endorses Horwitz’s central thesis that advocates of a contemporary “freedom of the Church” have overlooked historical complexities in marking the 11th-century investiture conflict between Henry IV and Pope Gregory VII, often simply referred to “Canossa” after the small Emilian village where Henry sought absolution from Gregory, as the birth of that freedom. The essay goes beyond Horwitz to argue that the historical account of “Canossa” presupposed by freedom-of-the-Church advocates is literally false. “Canossa,” instead, is a myth. More salient, nonmythical analogies for a “freedom of the Church” exist in U.S. constitutional history: genuine state sovereignty and dual-sovereignty federalism from the 19th century, and state dignity and native American domestic dependency from the contemporary era. These more historically accessible analogies all suggest that any “freedom of the Church” in U.S. constitutional doctrine is greatly diminished from the robust freedom argued for by those who invoke “Canossa” as that freedom’s defining moment. But even the mythical “Canossa” remains important. Myths are stories that a society tells about itself, stories that preserve and clarify its deepest values and commitments. Like the “myth of Magna Carta” that has exerted so much influence on English and American constitutional law, “Canossa” emphasizes the dangers to liberty from a government that sees no bounds on its jurisdiction and authority. Though historically false, “Canossa” might be mythically true