Systems development of a stall/spin research facility using remotely controlled/augmented aircraft models. Volume 1: Systems overview

A ground based, general purpose, real time, digital control system simulator (CSS) is specified, developed, and integrated with the existing instrumentation van of the testing facility. This CSS is built around a PDP-11/55, and its operational software was developed to meet the dual goal of providing the immediate capability to represent the F-18 drop model control laws and the flexibility for expansion to represent more complex control laws typical of control configured vehicles. Overviews of the two CSS's developed are reviewed as well as the overall system after their integration with the existing facility. Also the latest version of the F-18 drop model control laws (REV D) is described and the changes needed for its incorporation in the digital and analog CSS's are discussed

Crackdown and Consent: China’s War on Terror and the Strategic Creation of a Public Discourse in the U.S.

Scholars have extensively detailed China’s conflation of the Uyghur issue in Xinjiang with the international war on terror following September 11, 2001. Less studied is how the U.S. responded to China’s framing of the Uyghur as terrorists, and of the Chinese government’s characterization of Xinjiang as a region fraught with violence and extremism. On the whole, scholars who have addressed this latter issue conclude that China successfully coopted the U.S., and consequently cracked down on Xinjiang without substantial international outrage. On the basis of a review of official U.S. documents before and after 9/11, I argue that the U.S. response to China’s framing of the Uyghur is not as clear-cut, and that multiple and conflicting U.S. responses emerged to the Uyghur-terrorist discourse. Specifically, the U.S. shifted from purely framing the Uyghur as victims of human rights abuses to projecting three new frames onto the Uyghur: victims of the war on terror; a minority group that may resort to violent methods of protest; and suspected terrorists. This new interpretation holds important ramifications for how scholars should understand China’s treatment of the Uyghur, as well as for Sino-U.S. relations

Non-Abelian Proca model based on the improved BFT formalism

We present the newly improved Batalin-Fradkin-Tyutin (BFT) Hamiltonian formalism and the generalization to the Lagrangian formulation, which provide the much more simple and transparent insight to the usual BFT method, with application to the non-Abelian Proca model which has been an difficult problem in the usual BFT method. The infinite terms of the effectively first class constraints can be made to be the regular power series forms by ingenious choice of $X_{\alpha \beta}$ and $\omega^{\alpha \beta}$-matrices. In this new method, the first class Hamiltonian, which also needs infinite correction terms is obtained simply by replacing the original variables in the original Hamiltonian with the BFT physical variables. Remarkably all the infinite correction terms can be expressed in the compact exponential form. We also show that in our model the Poisson brackets of the BFT physical variables in the extended phase space are the same structure as the Dirac brackets of the original phase space variables. With the help of both our newly developed Lagrangian formulation and Hamilton's equations of motion, we obtain the desired classical Lagrangian corresponding to the first class Hamiltonian which can be reduced to the generalized St\"uckelberg Lagrangian which is non-trivial conjecture in our infinitely many terms involved in Hamiltonian and Lagrangian.Comment: Notable improvements in Sec. I

New attractor mechanism for spherically symmetric extremal black holes

We introduce a new attractor mechanism to find the entropy for spherically symmetric extremal black holes. The key ingredient is to find a two-dimensional (2D) dilaton gravity with the dilaton potential $V(\phi)$. The condition of an attractor is given by $\nabla^2\phi=V(\phi_0)$ and $\bar{R}_2=-V^{\prime}(\phi_0)$ and for a constant dilaton $\phi=\phi_0$, these are also used to find the location of the degenerate horizon $r=r_{e}$ of an extremal black hole. As a nontrivial example, we consider an extremal regular black hole obtained from the coupled system of Einstein gravity and nonlinear electrodynamics. The desired Bekenstein-Hawking entropy is successfully recovered from the generalized entropy formula combined with the 2D dilaton gravity, while the entropy function approach does not work for obtaining this entropy.Comment: 20 pages, 4 figures, Accepted for publication in Physical Review D. This version includes revisions suggested by the refere

Design and Optimization of a Horizontal Axis Marine Current Turbine

As fossil fuels near depletion and their detrimental side effects become prominent on ecosystems, the world searches for renewable sources of energy. Marine current energy is an emerging and promising renewable energy resource. At the heart of the horizontal axis marine current turbines (HAMCT) are carefully designed hydrofoil sections and optimized blade twist and chord distribution. While there is growing needs to have hydrofoils that provide good hydrodynamic and structural performance, the hydrofoils also have to avoid cavitation due to high suction pressures. This study focuses on designing efficient hydrofoils - HM05XX series; this series has very good hydrodynamic properties and also these sections are thick enough to provide structural strength to the blades. The HM05XX series hydrofoils were used to design and optimize HAMCT. The designed HAMCT has rated operating speed of 1.5 m/s, cut in speed of 0.5 m/s and cut-off speed of 3 m/s. The turbine was optimized using HARP-Opt (Horizontal axis rotor optimization) code that utilizes a multiple objective genetic algorithm and blade-element momentum (BEM) theory flow model to design horizontal-axis wind and hydrokinetic turbine rotors

Quantization of spontaneously broken gauge theory based on the BFT-BFV Formalism

We quantize the spontaneously broken abelian U(1) Higgs model by using the improved BFT and BFV formalisms. We have constructed the BFT physical fields, and obtain the first class observables including the Hamiltonian in terms of these fields. We have also explicitly shown that there are exact form invariances between the second class and first class quantities. Then, according to the BFV formalism, we have derived the corresponding Lagrangian having U(1) gauge symmetry. We also discuss at the classical level how one easily gets the first class Lagrangian from the symmetry-broken second class Lagrangian.Comment: 16 pages, latex, final version published in Mod. Phys. Lett.