Model-independent resonance parameter extraction using the trace of K and T matrices

A model-independent method for the determination of Breit-Wigner resonance parameters is presented. The method is based on eliminating the dependence on the choice of channel basis by analyzing the trace of the K and T matrices in the coupled-channel formalism, rather than individual matrix elements of the multichannel scattering matrix.Comment: 6 pages, 16 figure

Experimental Study of Airfoil Trailing Edge Noise: Instrumentation, Methodology and Initial Results

The mechanisms of aerodynamic noise generation at the trailing edge of an airfoil is investigated. Instrumentation was designed, a miniature semiconductor strain-gauge pressure transducer and associated electronic amplifier circuitry were designed and tested and digital signal analysis techniques applied to gain insight into the relationship between the dynamic pressure close to the trailing edge and the sound in the acoustic far-field. Attempts are made to verify some trailing-edge noise generation characteristics as theoretically predicted by several contemporary acousticians. It is found that the noise detected in the far-field is comprised of the sum of many uncorrelated emissions radiating from the vicinity of the trailing edge. These emissions appear to be the result of acoustic energy radiation which has been converted by the trailing-edge noise mechanism from the dynamic fluid energy of independent streamwise 'strips' of the turbulent boundary layer flow

Vapor Pressures For The System Isobutane-Isobutylene-n-Butane

New experimental vapor pressures for the ternary system composed of Isobutane-isobutylene-n-butane from 40 to 160 °F and 20 to 160 psia are presented. The data have an estimated average accuracy of 0.04%. The pure component data are compared with existing data from the literature. © 1978, American Chemical Society. All rights reserved

Direct Solution Of The Isothermal Gibbs-Duhem Equation For Multicomponent Systems

The numerical solution of the relative volatility form of the isothermal Gibbs-Duhem equation for multicomponent systems Is carried out by a relaxation technique for two ternary systems at five different temperatures. This direct method of solution eliminates calculating and differentiating the excess Gibbs free energy as required by other indirect methods. © 1978, American Chemical Society. All rights reserved

Discount rates used for forest valuation - results of 2017 survey

A total of 23 forest valuers responded to the survey and provided information on 19 New Zealand and eight Australian transactions in 2016 and 2017. The average reported implied discount rate (IDR) for New Zealand transactions is 7.0% (range 4.0% to 9.2%) for current rotation post-tax cashflows and 7.6% (range 4.0% to 10.7%) for pre-tax cashflows, compared to 6.9% and 8.6% in the 2015 survey. IDRs for the four transactions of medium or large forests are, on average, lower than for the 15 small forests; 5.8% versus 7.2% for post-tax cashflows and 5.9% versus 8.4% for pre-tax cashflows. The eight reported Australian transactions are all medium or large forests. For current rotation pre-tax cashflows the range of IDRs is 7.7 to 10.8% with an average of 8.5%. Forest valuers provided the discount rate they use to estimate the market value of a forest. Valuers apply a discount rate in the range 6% to 10% (average 7.1%) to post-tax cashflows or a discount rate also in the range 6% to 10% (average 7.6%) to pre-tax cashflows. Fourteen of the 23 valuers included in the 2017 survey also participated in the 2015 survey. They are using discount rates for forest valuation that are, on average, 0.6% lower than in 2015. Although eight of these valuers are using a lower discount rate, the other six use the same, or higher, average discount rates in 2017 as they did in 2015

Full-Scale Wind-Tunnel Tests of a PCA-2 Autogiro Rotor

This report presents the results of force tests on and air-flow surveys near PCA-2 autogiro rotor in the NACA full-scale wind tunnel. The force tests were made at three pitch settings and several rotor speeds; the effect of fairing protuberances on the rotor blade was determined. Induced downwash and yaw angles were determined at low tip-speed ratios in a plane 1 1/2 feet above the path of the blade tips. The results show that the maximum l/d of the rotor cannot be appreciably increased by increasing the blade pitch angle above about 4.5 degrees at the blade tip; that the protuberances on the blades cause more than 5 percent of the total rotor drag; and that the rotor center-of-pressure travel is very small