The impact of circulation control on rotary aircraft controls systems

Application of circulation to rotary wing systems is a new development. Efforts to determine the near and far field flow patterns and to analytically predict those flow patterns have been underway for some years. Rotary wing applications present a new set of challenges in circulation control technology. Rotary wing sections must accommodate substantial Mach number, free stream dynamic pressure and section angle of attack variation at each flight condition within the design envelope. They must also be capable of short term circulation blowing modulation to produce control moments and vibration alleviation in addition to a lift augmentation function. Control system design must provide this primary control moment, vibration alleviation and lift augmentation function. To accomplish this, one must simultaneously control the compressed air source and its distribution. The control law algorithm must therefore address the compressor as the air source, the plenum as the air pressure storage and the pneumatic flow gates or valves that distribute and meter the stored pressure to the rotating blades. Also, mechanical collective blade pitch, rotor shaft angle of attack and engine power control must be maintained

Operation of a forced circulation, croloy 9 m, mercury loop to study corrosion product separation techniques

Forced circulation, Croloy 9M mercury loop designed to investigate corrosion product separation technique

The Vector Analyzing Power in Elastic Electron-Nucleus Scattering

The vector analyzing power A_n is calculated for elastic electron scattering from a variety of spin zero nuclei at energies from 14 MeV to 3 GeV. Time reversal symmetry insures that A_n vanish in first Born approximation. Therefore A_n depends on Coulomb distortions and can be large for scattering from heavy nuclei. The vector analyzing power is a potential source of systematic error for parity violation experiments. We find that A_n=-0.361 ppm for the kinematics of the Parity Radius Experiment (PREX) involving 850 MeV electrons scattering at six degrees from 208Pb. This is comparable to the parity violating asymmetry. However for HAPPEX He involving 3 GeV electrons scattering on 4He we find that A_n is very small.Comment: 6 pages, 6 figures, submitted to Phys. Rev.

Non-equilibrium dynamics in quantum field theory at high density: the tsunami

The dynamics of a dense relativistic quantum fluid out of thermodynamic equilibrium is studied in the framework of the Phi^4 scalar field theory in the large N limit. The time evolution of a particle distribution in momentum space (the tsunami) is computed. The effective mass felt by the particles in such a high density medium equals the tree level mass plus the expectation value of the squared field. The case of negative tree level squared mass is particularly interesting. In such case dynamical symmetry restoration as well as dynamical symmetry breaking can happen. Furthermore, the symmetry may stay broken with vanishing asymptotic squared mass showing the presence of out of equilibrium Goldstone bosons. We study these phenomena and identify the set of initial conditions that lead to each case. We compute the equation of state which turns to depend on the initial state. Although the system does not thermalize, the equation of state for asymptotically broken symmetry is of radiation type. We compute the correlation functions at equal times. The two point correlator for late times is the sum of different terms. One stems from the initial particle distribution. Another term accounts for the out of equilibrium Goldstone bosons created by spinodal unstabilities when the symmetry is asymptotically broken.Both terms are of the order of the inverse of the coupling for distances where causal signals can connect the two points. The contribution of the out of equilibrium Goldstones exhibits scaling behaviour in a generalized sense.Comment: LaTex, 49 pages, 15 .ps figure

The Proposed U.S.-South Korea Free Trade Agreement (KORUS FTA): Provisions and Implications

[Excerpt] On June 30, 2007, U.S. and South Korean trade officials signed the proposed U.S.-South Korean Free Trade Agreement (KORUS FTA) for their respective countries. If approved, the KORUS FTA would be the second-largest FTA that South Korea has signed to date, after the agreement with the European Union (EU). It would be the second-largest (next to North American Free Trade Agreement, NAFTA) in which the United States participates. South Korea is the seventhlargest trading partner of the United States and the United States is South Korea’s third-largest trading partner. Various studies conclude that the agreement would increase bilateral trade and investment flows. The final text of the proposed KORUS FTA covers a wide range of trade and investment issues and, therefore, could have substantial economic implications for both the United States and South Korea. The agreement will not enter into force unless Congress approves implementation legislation. The negotiations were conducted under the trade promotion authority (TPA), also called fast-track trade authority, that Congress granted the President under the Bipartisan Trade Promotion Act of 2002 (P.L. 107-210). Under TPA the President has the discretion on when to submit the implementing legislation to Congress. President Bush did not submit the legislation because of differences with the Democratic leadership over treatment of autos and beef, among other issues. Early in his Administration, President Obama indicated the need to resolve those issues before he would submit the implementing legislation. On December 3, 2010, after a series of arduous negotiations and missed deadlines, President Obama and President Lee announced that their negotiators reached agreement on modifications in the KORUS FTA, and that they were prepared to move ahead to getting the agreement approved by the respective legislatures. The White House is expected to send implementing legislation to the 112th Congress and that it would like to see Congress approve the agreement by July 1 of this year. The modifications are in the form of changes in phase-out periods for tariffs on autos, a new safeguard provision on autos, and concessions by South Korea on allowing a larger number of U.S. cars into South Korea under U.S. safety standards than was the case under the original KORUS FTA provisions. The issue of full U.S. beef access was not resolved because of the political sensitivity of the issue in South Korea. In 2008, when President Lee reached a separate agreement with the United States to lift South Korea’s ban on U.S. beef imports, massive anti-South Korean government protests forced the two governments to renegotiate its terms. The U.S. beef sector has largely supported the KORUS FTA. A broad swath of the U.S. business community supports the KORUS FTA . With the modifications in the agreement reached in December, this group also includes the three Detroit-based auto manufacturers and the United Auto Workers (UAW) union. It still faces opposition from some labor unions and other groups, including Public Citizen. Many U.S. supporters view passage of the KORUS FTA as important to secure new opportunities in the South Korean market, while opponents claim that the KORUS FTA does not go far enough to break down South Korean trade barriers or that the agreement will encourage U.S. companies to move their production offshore at the expense of U.S. workers. Other observers have suggested the outcome of the KORUS FTA could have implications for the U.S.-South Korean alliance as a whole, as well as on U.S. Asia policy and U.S. trade policy, particularly in light of an FTA signed in by South Korea and the EU that is expected to go into effect on July 1, 2011

Measuring the Superfluid Fraction of an Ultracold Atomic Gas

We propose a method to measure the superfluid fraction of an atomic gas. The method involves the use of a vector potential generated by optical beams with non-zero angular momentum to simulate uniform rotation. The induced change in angular momentum of the atomic gas can be measured spectroscopically. This allows a direct determination of the superfluid fraction.Comment: 4 pages, 2 figure

The EU-South Korea Free Trade Agreement and Its Implications for the United States

[Excerpt] On October 6,2010, the 27 member European Union (EU) and South Korea signed a bilateral free trade agreement (FTA). The agreement is expected to go into effect on July 1, 2011, pending approval by the European Parliament and the South Korean National Assembly. If enacted, the South Korea-EU FTA (KOREU FTA) would be the largest FTA in terms of market size that South Korea has entered into. The KOREU FTA reflects the EU and South Korean trade strategies to use FTAs to strengthen economic ties outside their home regions. It also builds upon the surge in trade and investment flows between South Korea and the EU over the past decade. This agreement has possible implications for U.S. trade with South Korea and congressional action on the proposed U.S.-South Korea FTA (KORUS FTA). The proposed KOREU FTA is very comprehensive. It would reduce and eliminate tariffs and other trade barriers in manufactured goods, agricultural products and services and would also cover such trade-related activities as government procurement, intellectual property rights, labor rights and environmental issues. Most studies done on the potential impact of the KOREU FTA estimate that the agreement will have a small but positive effect on the economies of the EU and South Korea as a whole and that the larger relative impact would be on the South Korean economy. The greatest economic impact of the KOREU FTA would be on specific sectors in each economy. EU services providers would be expected to experience gains from the agreement, especially in the areas of retail and wholesale trade, transportation services, financial services, and business services. In terms of trade in goods, EU exporters of pharmaceuticals, auto parts, industrial machinery, electronics parts, and some agricultural goods and processed foods would be expected to gain from the KOREU FTA\u27s implementation. At the same time, South Korean manufacturers of cars, ships, wireless telecommunications devices, chemical products, and imaging equipment would be expected to increase their exports to the EU market. The KOREU FTA is similar to the proposed KORUS FTA in many respects. Both agreements are comprehensive and both would eliminate tariffs on most trade in goods soon after they enter into force. However, they differ in other respects. Phase-out periods for tariffs on some manufactured goods differ. In addition, the KOREU FTA does not cover foreign direct investment. Unlike the KORUS FTA, the KOREU FTA would not allow trade sanctions to be applied where violations of the workers\u27 rights, and environment provisions have been deemed to occur. In addition, the KORUS FTA would cover a broader range of trade in services than would the KOREU FTA. It is not clear whether these differences in the structures of the FTAs would result in appreciable differences in outcomes in terms of economic gains and losses. U.S. and European firms are close competitors in a number of sectors and industries, particularly autos. Some business representatives argue that enactment of the KOREU FTA before enactment of the KORUS FTA would give European competitors commercial first mover advantages, since EU firms, such as those in the auto industry or the services sector, could gain greater market opportunities in South Korea not afforded to US. firms. On the other hand, other factors could also mitigate such advantages. For example, U.S. multinational firms operating in the EU could benefit from the KOREU FTA. Nevertheless, the content and fate of the KOREU FTA could influence the pace and tone of any debate in the United States on the KORUS FTA in the 112th Congress

Analytic and Numerical Study of Preheating Dynamics

We analyze the phenomenon of preheating,i.e. explosive particle production due to parametric amplification of quantum fluctuations in the unbroken case, or spinodal instabilities in the broken phase, using the Minkowski space $O(N)$ vector model in the large $N$ limit to study the non-perturbative issues involved. We give analytic results for weak couplings and times short compared to the time at which the fluctuations become of the same order as the tree level,as well as numerical results including the full backreaction.In the case where the symmetry is unbroken, the analytic results agree spectacularly well with the numerical ones in their common domain of validity. In the broken symmetry case, slow roll initial conditions from the unstable minimum at the origin, give rise to a new and unexpected phenomenon: the dynamical relaxation of the vacuum energy.That is, particles are abundantly produced at the expense of the quantum vacuum energy while the zero mode comes back to almost its initial value.In both cases we obtain analytically and numerically the equation of state which turns to be written in terms of an effective polytropic index that interpolates between vacuum and radiation-like domination. We find that simplified analysis based on harmonic behavior of the zero mode, giving rise to a Mathieu equation forthe non-zero modes miss important physics. Furthermore, analysis that do not include the full backreaction do not conserve energy, resulting in unbound particle production. Our results do not support the recent claim of symmetry restoration by non-equilibrium fluctuations.Finally estimates of the reheating temperature are given,as well as a discussion of the inconsistency of a kinetic approach to thermalization when a non-perturbatively large number of particles is created.Comment: Latex file, 52 pages and 24 figures in .ps files. Minor changes. To appear in Physical Review D, 15 December 199

Resumming the large-N approximation for time evolving quantum systems

In this paper we discuss two methods of resumming the leading and next to leading order in 1/N diagrams for the quartic O(N) model. These two approaches have the property that they preserve both boundedness and positivity for expectation values of operators in our numerical simulations. These approximations can be understood either in terms of a truncation to the infinitely coupled Schwinger-Dyson hierarchy of equations, or by choosing a particular two-particle irreducible vacuum energy graph in the effective action of the Cornwall-Jackiw-Tomboulis formalism. We confine our discussion to the case of quantum mechanics where the Lagrangian is $L(x,\dot{x}) = (1/2) \sum_{i=1}^{N} \dot{x}_i^2 - (g/8N) [ \sum_{i=1}^{N} x_i^2 - r_0^2 ]^{2}$. The key to these approximations is to treat both the $x$ propagator and the $x^2$ propagator on similar footing which leads to a theory whose graphs have the same topology as QED with the $x^2$ propagator playing the role of the photon. The bare vertex approximation is obtained by replacing the exact vertex function by the bare one in the exact Schwinger-Dyson equations for the one and two point functions. The second approximation, which we call the dynamic Debye screening approximation, makes the further approximation of replacing the exact $x^2$ propagator by its value at leading order in the 1/N expansion. These two approximations are compared with exact numerical simulations for the quantum roll problem. The bare vertex approximation captures the physics at large and modest $N$ better than the dynamic Debye screening approximation.Comment: 30 pages, 12 figures. The color version of a few figures are separately liste