Chiral Extension of Lattice Gauge Theory

Two approaches are presented to coupling explicit Goldstone modes to $N_f$ flavors of massless quarks preserving exact $SU(N_f) \times SU(N_f)$ chiral symmetry on the lattice. The first approach is a generalization a chiral extension to QCD (aka XQCD) proposed by Brower, Shen and Tan consistent with the Ginsparg-Wilson relation. The second approach based on the Callan,Coleman, Wess and Zumino coset construction has a real determinant atzero quark axial coupling, $g_A = 0$.Comment: Lattice2003 3 pages, 1 figur

Compressible Dynamic Stall Control using a Variable Droop Leading Edge Airfoil

(AIAA Paper 2003-0048), Journal of Aircraft, Vol. 41, No. 4, pp. 862-969, Jul. - Aug. 2004.The control of compressible dynamic stall using a variable droop leading edge airfoil is described. The leading 25% of a VR-12 airfoil is drooped as it executes sinusoidal pitch oscillations such that the leading portion of the airfoil is always at a low effective incidence to the flow. Airfoil performance data determined for freestream Mach numbers ranging from 0.2 to 0.4, at reduced frequencies from 0 to 0.1, and using unsteady pressure transducer measurements, show that droop reduces the tendency of the airfoil to enter the dynamic stall state. Even when it does, the strength of the dynamic stall vortex is significantly reduced, which is reflected in the 40 to 50% smaller negative peak pitching-moment values, with positive damping of the airfoil. Also, the airfoil drag when the droop is dynamically varied is reduced by up to 75% relative to a nondrooped airfoil, making a strong case for the use of this concept for dynamic stall control.U.S. Army Research Offic

Interferometric investigations of compressible dynamic stall over a transiently pitching airfoil

The dynamic stall flow field over NACA 0012 airfoil pitching transiently from 0 - 60 at a constant rate under compressible flow conditions has been studied using the real-time technique of point diffraction interferometry. This investigation using nonintrusive diagnostics provides a quantitative description of the overall flow field, including the finer details of dynamic stall vortex formation, growth and the concomitant changes in the pressure distribution. Analysis of several hundred interferograms obtained for a range of flow conditions shows that the peak leading edge suction pressure coefficient that stall is nearly constant for a given free stream Mach number at all nondimensional pitch rates. Also, this value is below that seen in steady flow at static stall for the same Mach number, indicating that dynamic effects significantly effect the separation behavior. Further, for a given Mach number, the dynamic stall vortex seems to form rapidly at nearly the same angle of attack for all pitch rates studied. As the vortex is shed, it induces an anti-clockwise trailing edge vortex, which grows in a manner similar to that of a starting vortex. The measured peak suction pressure coefficient drops as the free stream Mach number increases. For free stream Mach numbers above 0.4, small multiple shocks appear near the leading edge

Design and Development of a Dynamically Deforming Leading Edge Airfoil for Unsteady Flow Control

ICIASF '97 RECORD, IEEE Publication No. 97CH36121, pp. 132-140.A novel approach to unsteady flow separation and dynamic stall control using a dynamically deforming leading edge airfoil is described. The design details of a carbon-fiber composite skin airfoil having a thickness of 0.002 in. at the leading edge and capable of deforming at 20 Hz in unsteady flow at freestream Mach numbers of up to 0.45, are discussed. Implementation of the scheme at model scales places extraordinary demands on the design, material and fabrication of such an airfoil. Rate scaling further requires very-rapid-response instrumental ion, measurement techniques and data acquisition schemes. The special instrumentation control system developed for these experiments as well as the fluid dynamic results of successful flow control that was achieved using this method, are also discussed.U.S. Army Research Office ARO MIPR 133-94, ARO 32480.11-EGU.S. Army Research Office ARO MIPR 133-94, ARO 32480.11-E

COMPARISION OF EFFICACYAND SAFETY OF ORAL LABETALOL AND NIFEDIPINE IN PREECLAMPSIA: A PROSPECTIVE OBSERVATIONAL STUDY

Objective: To compare the efficacy and safety of oral Labetalol and Nifedipine in preeclampsia patients and to aid professionals in making appropriate therapeutic decisions in the management of preeclampsia.Methods: A Prospective observational study with the total of 152 pregnant women with preeclampsia is conducted in a Tertiary Care Hospital in India. Pregnant women with preeclampsia prescribed with either oral labetalol or oral nifedipine were selected. Main outcome measures include monitoring of adverse effects of labetalol and nifedipine and efficacy of both drugs. Blood pressures were measured every 4 hrs using sphygmomanometer and average of three consecutive readings is recorded. The two groups were followed until delivery and are interviewed for any adverse reactions.Results: The duration of days required for labetalol to normalize the high blood pressure is 5 days (5±2.63 d), and that of nifedipine is 7.5 days (7.5±3.83 d) with P value of 0.0015. Common adverse Drug reactions (ADR's) of the both drugs are pedal edema (50%, 47.36%), headache (44.7%, 26.31%), and orthostatic hypotension (9%, 7%) etc are compared.Conclusion: Oral Labetalol is more efficacious than Oral Nifedipine, with an exception of more adverse effects and high cost.Â