Accurate modeling of airplane fuel consumption is necessary for air transportation policy-makers to properly adjudicate trades between competing environmental and economic demands. Existing public models used for computing terminal-area airplane fuel consumption have been shown to have substantial errors, potentially leading to erroneous policy and investment decisions. The method of modeling fuel consumption proposed in this paper was developed using data from a major airplane manufacturer. When compared with airline performance/operational data, this proposed method has been shown to accurately predict fuel consumption in the terminal area. The proposed method uses airplane performance data from publicly available environmental models supported by the Federal Aviation Administration and others. The proposed method has sufficient generality to protect the proprietary interests of the manufacturer, while still having adequate fidelity to analyze low-speed airplane operations in the terminal area. This improved methodology will enable more informed decisions by policy-makers seeking to account for the effects of fuel consumption and airplane emissions on plans for future airspace and airport designs.Nomenclature Fo = static thrust at sea level standard conditions F= = net corrected thrust h MSL = height above mean sea level K 1 = departure thrust specific fuel consumption constant coefficient K 2 = departure thrust specific fuel consumption Mach number coefficient K 3 = departure thrust specific fuel consumption altitude coefficient K 4 = departure thrust specific fuel consumption thrust coefficient M = Mach number = arrival thrust specific fuel consumption constant coefficient 1 = arrival thrust specific fuel consumption Mach number coefficient 2 = arrival thrust specific fuel consumption thrust term coefficient 3 = arrival thrust specific fuel consumption thrust coefficient = pressure ratio = temperature ratio

Previous studies have utilized articular cartilage from joints as a model to investigate the influence of various constituents in a connective tissue matrix on ultrasonic properties. These studies have assumed a degree of homogeneity of articular cartilage taken from the same joint. However, tactile loads on articular cartilage vary significantly with location in a joint, and the effects of mechanical load on the connective tissue matrix and the resulting effects on ultrasonic properties are not known. This work reports the variations in acoustical properties of bovine articular cartilage from the stifle (knee) joint both among different joints and within each joint. A pulse-echo transmission technique was used to measure acoustic attenuation in the frequency range of 10 to 40 MHz. The attenuation coefficient was characterized by the integrated attenuation (mean value) over the frequency bandwidth considered. Integrated attenuation averaged over each joint varied among joints from 3.2 to 7.5 NP/cm (6.0 +/- 2.0, mean +/- s.d.). Additionally, a linear regression (r = 0.59) of all the data versus location along the patellar groove indicated that within joints integrated attenuation increased from proximal to distal locations by 6% to 60% (32 +/- 25, mean +/- s.d.). The variations observed among joints and along the patellar groove within a given joint suggest that studies utilizing articular cartilage to determine the role of connective tissue constituents on acoustic properties require control for joint and location. An additional outcome of this study was the observation that damage to the load-bearing surface of articular cartilage may be detectable ultrasonically through characteristics of the acoustic reflection from the articular surface.

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A noise measurement study was conducted at Logan International Airport in Boston, Massachusetts, during the summer of 1999 to examine the applicability of currently available mathematical models of lateral sound attenuation. Analysis of the data collected revealed that lateral attenuation is a function of the location of the engines on the aircraft, i.e., tail-mounted versus wing-mounted. Attenuation for aircraft with tail-mounted engines was found to agree with the published literature, as well as that included in existing aircraft noise models. Attenuation for aircraft with wing-mounted engines was found to be less than that documented in the literature. This lower lateral attenuation for aircraft with wing-mounted engines results in a general under-prediction of side-line noise by the existing noise models. © 2002 Institute of Noise Control Engineering.

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