Reparameterization Invariance to all Orders in Heavy Quark Effective Theory

Heavy Quark Effective Theory splits a heavy quark momentum into a large fixed momentum and a variable residual momentum, p = m_Q v + k. It thereby suffers a redundancy of description corresponding to small changes in the choice of the fixed velocity, v. The fact that full QCD is manifestly v-independent should lead to a non-trivial constraint on the form of the effective theory, known as Reparameterization Invariance. For spin-1/2 quarks, the precise form of the constraint and its solution at the level of the effective lagrangian have proven to be rather subtle, and the original proposal by Luke and Manohar has been questioned. In this paper I employ a version of Heavy Quark Effective Theory containing the ``anti-particle'' field as a non-propagating auxiliary field, which greatly simplifies keeping track of v-dependence. This permits a very simple derivation of Reparameterization Invariance from first principles. The auxiliary field can also be integrated out to return to the standard formulation of the effective theory, but with the effective lagrangian now satisfying the full reparameterization constraint. I compare this result with earlier proposals.Comment: 12 pages, LaTex. Important and confusing typographical error in eq. (15) corrected. To appear in Phys. Rev.

Identification and verification of frequency-domain models for XV-15 tilt-rotor aircraft dynamics

Frequency-domain methods are used to extract the open-loop dynamics of the XV-15 tilt-rotor aircraft from flight test data for the cruise condition (V = 170 knots). The frequency responses are numerically fitted with transfer-function forms to identify equivalent model characteristics. The associated handling quality parameters meet or exceed Level 2, Category A, requirements for fixed-wing military aircraft. Step response matching is used to verify the time-domain fidelity of the transfer-function models for the cruise and hover flight conditions. The transient responses of the model and aircraft are in close agreement in all cases, except for the normal acceleration response to elevator deflection in cruise. This discrepancy is probably due to the unmodeled rotor rpm dynamics. The utility of the frequency-domain approach for dynamics identification and analysis is clearly demonstrated

Situational Awareness and Synthetic Vision for Unmanned Aerial Vehicle Flight Testing

The Advanced Navigation Technology (ANT) Center at the Air Force Institute of Technology (AFIT) is currently exploring ways to develop and advance the employment of autonomous Unmanned Aerial Vehicles (UAV) by the Department of Defense for military purposes. The research in this thesis describes the development of a tool that enhances situational awareness and provides synthetic vision in a program called the Aviator Visual Display Simulator (AVDS) during UAV flight. During flight testing, the Situational Awareness and Synthetic Vision Relay Tool (SASVRT) developed provides the test coordinator and pilot, as well as the safety observers, with the most pertinent information regarding operational safety. In addition to improved safety, the enhanced situational awareness provided by SASVRT provides improved operational capabilities. SASVRT provides users with real-time information regarding hard boundaries, interpolated terrain, flight ceilings, and other aerial vehicles present. The hard boundary is a user defined area within which the UAV is to stay at all tirn.es e.g. as designated by a Safety Review Board (SRB). Pertinent data to this boundary is both distance and time until crossing, and is provided to the user during flight by SASVRT. The interpolated terrain part of SASVRT allows the user to input contours of altitude and based on all present information, interpolates a minimum safe altitude for flight. This information is also relayed to the user during flight. If multiple aerial vehicles are recognized by the autopilot operator interface) SASVRT will relay to the user the distances between a vehicle and any other vehicles present. Finally, in order to provide synthetic vision, SASVR:T relays telemetry data from the aircraft to AVDS, an aircraft simulation program, to provide a real-time visualization of the aircraft\u27s position and attitude relative to a synthetic terrain constructed based on information entered by the user. The visualization can be thought of as the view from a virtual camera that can be placed anywhere relative to the UAV or ground. Furthermore, the virtual camera can be oriented such that it provides a view from the cockpit, providing synthetic vision for the UAV operator, the fidelity of which is limited only by available maps and GPS accuracy. This report and the accompanying SASVRT program, provide a much enhanced methodology for safe operation during UAV flight testing, as well as improved operational capabilities

An Objective and Practical Test for Adjudicating Political Patronage Dismissals

Political patronage dismissal is not a new phenomenon, but judicial recognition of claims specifically alleging improper dismissal based on political affiliation has occurred only within the last twenty years. While the federal circuit courts have struggled to establish a standard by which to adjudicate patronage dismissal cases, their struggles have resulted in a plethora of inconsistent conclusions. Neither has the Supreme Court constructed a sufficiently concrete test to determine when an employee is exempt from patronage dismissal. The Elrod test is flawed in not limiting dismissals to political policymakers, and the Branti test is inadequate as it delegates the selection of occupations requiring political affiliation to the hiring authority. This subjectivity, combined with the absence of a concrete standard applicable to other job classifications, indicates that a proper standard is needed. This Note suggests that a workable standard exists in an objective examination of the duties performed by individual employees

The Effect of Fruit Acids on Aluminum

Aluminum has been used in cooking utensils for about thirty years and is still the favorite material employed. There is no disagreeable taste, odor or discoloration discernible from its use. There have been many experiments to prove that aluminum does not depreciate the quality of the food cooked in it. It does, however, add itself to the acidic and basic foods cooked therein. The amount taken up by neutral foods is negligible. For experimental purposes, fruit juices were chosen as the attacking substances and the strips of aluminum were of the quality used in ordinary cooking utensils, not cast aluminum