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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 307 records · Page 17

When One Cannot Bypass the Byproducts: Plastic Packaging Waste Embedded in Production and Export

While packaging is praised for reducing waste of perishable food products, packaging waste is a growing concern. Its least recyclable type, plastics waste, is increasingly polluting the marine environment and many developing countries are now refusing to take the waste from developed countries. Before responsibility can be established, one has to identify the key producers and consumers. This paper adjusts the packaging waste satellite account in EXIOBASE 3 by combining the official waste data published by the World Bank. Based on input-output methods, we find that the world's top suppliers of plastic packaging waste are the United States, China, and Brazil. Food and beverage products constitute the bulk of the problem. Yet, 21% of these countries' plastic packaging waste is induced export. At the global level, it is 25.8%. About 76.0% of export-induced plastic packaging waste corresponds to packaging of the exported goods that will ultimately be disposed of in the destination country; while the others correspond to the packaging used in their supply-chain and wasted domestically. We conclude that international efforts need to assign shared responsibility and promote improvement in plastic packaging recyclability.

environment responsibility↗

Locality-Driven Dynamic GPU Cache Bypassing

This paper presents novel cache optimizations for massively parallel, throughput-oriented architectures like GPUs. Based on the reuse characteristics of GPU workloads, we propose a design that integrates such efficient locality filtering capability into the decoupled tag store of the existing L1 D-cache through simple and cost-effective hardware extensions.

architecture optimization↗

Bypass Flow Model Implementation for VERA BWR

The Virtual Environment for Reactor Applications (VERA) has been developed by the Consortium for Advanced Simulation of LWRs (CASL) over the past 10 years to address difficult problems facing commercial light-water reactors (LWRs). VERA comprises several high-fidelity physics packages, each of which models a different aspect of the reactor. These individual pieces are then linked to provide a fully coupled multiphysics solution for various LWR analyses.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Effect of exhaust nozzle configuration on aerodynamic and acoustic performance of an externally blown flap system with a quiet 6:1 bypass ratio engine

A highly suppressed TF-34 engine was used to investigate engine and flap interaction noise associated with an externally blown flap STOL powered lift system. Noise, efficiency, and velocity decay characteristics of mixed and separate flow exhaust systems including convergent, co-annular, and lobed designs were determined with the engine operating alone. Noise data were then obtained for several of the exhaust configurations with the engine blowing a wing-flap segment. Noise for both the engine alone and the engine with blown flaps showed substantial differences for the various exhaust configurations tested. The differences in observed noise are related primarily to nozzle effective exhaust velocity, flap impingement velocity, and noise spectral shape.

Samanich, N. E.↗

Investigation of noise from full-scale high bypass engine and blown flap system

A summary is presented of an acoustic test program for investigating engine noise suppression and jet/flap interaction noise associated with an EBF STOL powered lift system. A highly suppressed TF-34 engine and EBF wing were used in the investigation. The engine was suppressed 21 PndB to a level of 94 PndB. An UTW powered lift system was tested with conventional, mixer, and decayer-type nozzles. The configuration with velocity decayer nozzle and acoustically treated shroud had the lowest noise (98 PndB). An OTW configuration with non-decayer nozzle was about 10 db quieter than the corresponding UTW system. UTW and OTW noise data are compared with scale model correlations.

Jones, W. L.↗

Highly noise suppressed bypass 6 engine for STOL application

A TF-34 engine with an acoustically treated ground test nacelle was built and tested to determine the feasibility of suppressing fan and core engine noise to the stringent levels required for STOL or short-haul commercial aircraft. The design incorporates wall treatment for the fan and core plus three treated splitter rings in the inlet and two treated splitters in the aft fan duct. Maximum suppression of fan tone noise of 40-45 dB was obtained from both the inlet and aft fan treatment. At rated fan speed, overall noise was reduced by 21 PNdB to a value of 94 PNdB on a 500-foot sideline. The overall noise reduction value was limited by the jet noise floor. Thrust losses due to the acoustic treatment are also discussed.

Jones, W. L.↗

Effect of exhaust nozzle configuration on aerodynamic and acoustic performance of an externally blown flap system with a quiet 6:1 bypass ratio engine

A highly suppressed TF-34 engine was used to investigate engine and flap interaction noise associated with an externally blown flap STOL powered lift system. Noise, efficiency, and velocity decay characteristics of mixed and separate flow exhaust systems including convergent, co-annular, and lobed designs were determined with the engine operating alone. Noise data were then obtained for several of the exhaust configurations with the engine blowing a wing-flap segment. Noise for both the engine alone and the engine with blown flaps showed substantial differences for the various exhaust configurations tested. The differences in observed noise are related primarily to nozzle effective exhaust velocity, flap impingement velocity, and noise spectral shape.

Samanich, N. E.↗

Investigation of noise from full-scale high bypass engine and blown flap system

A summary is presented of an acoustic test program for investigating engine noise suppression and jet/flap interaction noise associated with an externally blown flap (EBF) STOL powered lift system. A highly suppressed TF-34 engine and EBF wing were used in the investigation. The engine was suppressed 21 PndB to a level of 94 PndB. An under the wing (UTW) powered lift system was tested with conventional, mixer, and decayer-type nozzles. The configuration with velocity decayer nozzle and acoustically treated shroud had the lowest noise (98 PndB). An over the wing (OTW) configuration with nondecayer nozzle was about 10 dB quieter than the corresponding UTW system. UTW and OTW noise data are compared with scale model correlations.

Jones, W. L.↗

Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan

The test program demonstrated that successful and rapid forward-to reverse-thrust transients can be performed without any significant engine operational limitations for fan blade pitch changes through either feather pitch or flat pitch. For through-feather-pitch operation with a flight inlet, fan stall problems were encountered, and a fan blade overshoot technique was used to establish reverse thrust.

Schaefer, J. W.↗