Quiet Clean Short-haul Experimental Engine (QCSEE). Core engine noise measurements

Noise measurements were taken on a turbofan engine which uses the same core, with minor modifications, employed on the quiet clean short-haul experimental engine (QCSEE) propulsion systems. Both nearfield and farfield noise measurements were taken in order to determine the core internally generated noise levels. The resulting noise measurements were compared to predicted combustor and turbine noise levels, to verify or improve the predicted QCSEE combustor and turbine noise levels

Quiet, Clean, Short-Haul Experimental Engine (QCSEE) Over-The-Wing (OTW) engine acoustic design

The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the over-the-wing (OTW) nacelle acoustic treatment design are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the OTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment

TF34 Quiet Nacelle nearfield acoustic test results

The results of the nearfield acoustic tests conducted on the TF34 Quiet Nacelle are presented. The high fan noise suppression levels being sought (26 PNdB reduction in aft noise) necessitated the use of an extensive system of special nearfield acoustic instrumentation to properly evaluate the suppression achieved. The design, operation, and test results from each of these nearfield acoustic instrumentation systems are presented

Acoustic design of the QCSEE propulsion systems

Acoustic design features and techniques employed in the Quiet Clean Short-Haul Experimental Engine (QCSEE) Program are described. The role of jet/flap noise in selecting the engine fan pressure ratio for powered lift propulsion systems is discussed. The QCSEE acoustic design features include a hybrid inlet (near-sonic throat velocity with acoustic treatment); low fan and core pressure ratios; low fan tip speeds; gear-driven fans; high and low frequency stacked core noise treatment; multiple-thickness treatment; bulk absorber treatment; and treatment on the stator vanes. The QCSEE designs represent and anticipated acoustic technology improvement of 12 to 16 PNdb relative to the noise levels of the low-noise engines used on current wide-body commercial jet transport aircraft

Effects of Fatty Acid Structure on Endothelial Cell Expression of Connexin43

The epidemic of obesity-related metabolic and cardiovascular diseases is linked to elevated fatty acids (FA). Epidemiological data argue that trans FA contribute to the development and progression of these disease processes. Previous work suggests the similarity in structure between saturated and trans FA may stimulate inflammation through trans FA interactions with toll-like receptor 4 (TLR4). To evaluate the impact of trans FA on cardiovascular health, the response of endothelial cells to trans FA was evaluated. Specifically, responses to the 18-carbon trans FA elaidic acid (EA) were compared to the same length cis FA oleic acid (OA). Endothelial cells were exposed to FA treatments for up to 48 hours and protein samples collected at specific times (1.5, 3, 6, 12, 24, and 48 hr). The expression of connexin43 (Cx43) was evaluated using Western blot analysis as a measure of their health (increasing in unhealthy endothelial cells). Lipopolysaccharide (LPS; 10 μg/mL), a TLR4 agonist, stimulated an increase in endothelial cell Cx43 expression at 12 hours. As the endothelial cells responded to a TLR4 agonist, they were then exposed to OA (30 μM), which decreased the expression of Cx43 at 3, 12, and 24 hours. In contrast, EA (30 μM) increased Cx43 expression at 12 hours. These results suggest that trans FA alter Cx43 expression in a similar pathway as LPS in endothelial cells (likely TLR4 signaling), whereas OA decreased Cx43, likely through a different mechanism

Quiet, Clean, Short-Haul, Experimental Engine (QCSEE) Under-The-Wing (UTW) engine acoustic design

The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the under-the-wing (UTW) engine boilerplate and composite nacelle acoustic treatment designs are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the UTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment

Spatial curvature effects on molecular transport by diffusion

For a substance diffusing on a curved surface, we obtain an explicit relation valid for very small values of the time, between the local concentration, the diffusion coefficient, the intrinsic spatial curvature and the time. We recover the known solution of Fick's law of diffusion in the flat space limit. In the biological context, this result would be useful in understanding the variations in the diffusion rates of integral proteins and other molecules on membranes.Comment: 10 page

Flight Simulator Evaluation of Enhanced Propulsion Control Modes for Emergency Operation

This paper describes piloted evaluation of enhanced propulsion control modes for emergency operation of aircraft. Fast Response and Overthrust modes were implemented to assess their ability to help avoid or mitigate potentially catastrophic situations, both on the ground and in flight. Tests were conducted to determine the reduction in takeoff distance achievable using the Overthrust mode. Also, improvements in Dutch roll damping, enabled by using yaw rate feedback to the engines to replace the function of a stuck rudder, were investigated. Finally, pilot workload and ability to handle the impaired aircraft on approach and landing were studied. The results showed that improvement in all aspects is possible with these enhanced propulsion control modes, but the way in which they are initiated and incorporated is important for pilot comfort and perceived benefit