Core compressor exit stage study. 1: Aerodynamic and mechanical design

The effect of aspect ratio on the performance of core compressor exit stages was demonstrated using two three stage, highly loaded, core compressors. Aspect ratio was identified as having a strong influence on compressors endwall loss. Both compressors simulated the last three stages of an advanced eight stage core compressor and were designed with the same 0.915 hub/tip ratio, 4.30 kg/sec (9.47 1bm/sec) inlet corrected flow, and 167 m/sec (547 ft/sec) corrected mean wheel speed. The first compressor had an aspect ratio of 0.81 and an overall pressure ratio of 1.357 at a design adiabatic efficiency of 88.3% with an average diffusion factor or 0.529. The aspect ratio of the second compressor was 1.22 with an overall pressure ratio of 1.324 at a design adiabatic efficiency of 88.7% with an average diffusion factor of 0.491

Core compressor exit stage study, 2

A total of two three-stage compressors were designed and tested to determine the effects of aspect ratio on compressor performance. The first compressor was designed with an aspect ratio of 0.81; the other, with an aspect ratio of 1.22. Both compressors had a hub-tip ratio of 0.915, representative of the rear stages of a core compressor, and both were designed to achieve a 15.0% surge margin at design pressure ratios of 1.357 and 1.324, respectively, at a mean wheel speed of 167 m/sec. At design speed the 0.81 aspect ratio compressor achieved a pressure ratio of 1.346 at a corrected flow of 4.28 kg/sec and an adiabatic efficiency of 86.1%. The 1.22 aspect ratio design achieved a pressure ratio of 1.314 at 4.35 kg/sec flow and 87.0% adiabatic efficiency. Surge margin to peak efficiency was 24.0% with the lower aspect ratio blading, compared with 12.4% with the higher aspect ratio blading

Results of acoustic testing of the JT8D-109 refan engines

A JT8D engine was modified to reduce jet noise levels by 6-8 PNdB at takeoff power without increasing fan generated noise levels. Designated the JT8D-109, the modified engines featured a larger single stage fan, and acoustic treatment in the fan discharge ducts. Noise levels were measured on an outdoor test facility for eight engine/acoustic treatment configurations. Compared to the baseline JT8D, the fully treated JT8D-109 showed reductions of 6 PNdB at takeoff, and 11 PNdB at a typical approach power setting

Structural insights into the mechanism of leptin receptor activation

Leptin is a master regulator of body weight and energy homeostasis that is dysregulated in obesity. Here, authors determined the cryo-EM structure of the activated Leptin receptor complex, revealing insights into the mechanism of Leptin signalin

Averaged <i>B</i>. <i>globigii</i> concentrations and TSS in the RAS and aeration basin effluent.

The light gray block shows the possible HRT range of 0.375 to 3.375 days, a black vertical line is the average calculated SRT of 23.6±5.6 days, and the darker gray block represents the possible SRT range of 18–32.1 days. SP1 and SP3 from both experiments were averaged for “average primary clarifier,” and likewise for SP4 and SP5 for “Average aeration basin.” The “+” and “x” series show the TSS in the aeration basin effluent and RAS, respectfully. Error bars were removed for visual clarity. Original data in S2 Text.</p

Phi-6 concentration response curves for Tests 1 and 2.

Concentration-time plot of individual sample ports over time for experiment 1 and experiment 2.</p