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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

The IAEA coordinated research programme on HTGR uncertainty analysis: Phase I status and Ex. I-1 prismatic reference results

The quantification of uncertainties in design and safety analysis of reactors is today not only broadly accepted, but in many cases became the preferred way to replace traditional conservative analysis for safety and licensing analysis. The use of a more fundamental methodology is also consistent with the reliable high fidelity physics models and robust, efficient, and accurate codes available today. To facilitate uncertainty analysis applications a comprehensive approach and methodology must be developed and applied, in contrast to the historical approach where sensitivity analysis were performed and uncertainties then determined by a simplified statistical combination of a few important input parameters. New methodologies are currently under development in the OECD/NEA Light Water Reactor (LWR) Uncertainty Analysis in Best-Estimate Modelling (UAM) benchmark activity. High Temperature Gas-cooled Reactor (HTGR) designs require specific treatment of the double heterogeneous fuel design and large graphite quantities at high temperatures. The IAEA has therefore launched a Coordinated Research Project (CRP) on HTGR Uncertainty Analysis in Modelling (UAM) in 2013 to study uncertainty propagation specifically in the HTGR analysis chain. Two benchmark problems are defined, with the prismatic design represented by the General Atomics (GA) MHTGR-350 and a 250 MW modular pebble bed design similar to the Chinese HTR-PM. Work has started on the first phase and the current CRP status is reported in the paper. A comparison of the Serpent and SCALE/KENO-VI reference Monte Carlo results for Ex. I-1 of the MHTGR-350 design is also included. It was observed that the SCALE/KENO-VI Continuous Energy (CE) k ∞ values were 395 pcm (Ex. I-1a) to 803 pcm (Ex. I-1b) higher than the respective Serpent lattice calculations, and that within the set of the SCALE results, the KENO-VI 238 Multi-Group (MG) k ∞ values were up to 800 pcm lower than the KENO-VI CE values. The use of the latest ENDF-B-VII.1 cross section library in Serpent lead to ~180 pcm lower k ∞ values compared to the older ENDF-B-VII.0 dataset, caused by the modified graphite neutron capture cross section. Furthermore, the fourth beta release of SCALE 6.2 likewise produced lower CE k∞ values when compared to SCALE 6.1, and the improved performance of the new 252-group library available in SCALE 6.2 is especially noteworthy. A SCALE/TSUNAMI uncertainty analysis of the Hot Full Power variant for Ex. I-1a furthermore concluded that the 238 U(n,γ) (capture) and 235 U(View the MathML source) cross-section covariance matrices contributed the most to the total k ∞ uncertainty of 0.58%.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

A fixed-target programme at the LHC for heavy-ion, hadron, spin and astroparticle physics: AFTER@LHC

Thanks to its multi-TeV LHC proton and lead beams, the LHC complex allows one to perform the most energetic fixed-target experiments ever and to study with high precision pp, pd and pA collisions at √ s NN = 115 GeV and Pbp and PbA collisions at √ s NN = 72 GeV. In conclusion we present a selection of feasibility studies for the production of quarkonia, open heavy-flavor mesons as well as light-flavor hadrons in pA and PbA collisions using the LHCb and ALICE detectors in a fixed-target mode.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Sociological survey in a municipality with a high level separate collection programme in an area of historic unpopularity

Highlights: • Behaviours, opinions and knowledge of citizens on MSW management were investigated. • The knowledge level was better than that of nearby university students and citizens. • The higher the education level, the greater the level of knowledge was. • The local authority showed a leading role in terms of waste management. • Trust is the key to any social program success including waste management programs. - Abstract: Behaviours, opinions and knowledge of citizens on MSW and separate collection were investigated in the city of Mercato San Severino (about 22,000 people), in the Campania region of Southern Italy that is an area suffering from a serious solid waste emergency that has lasted over 17 years due to the absence of treatment facilities. The image of heaps of rubbish in the streets of Naples and other nearby cities is only one side of the coin. Mercato San Severino has adopted an effective kerbside collection system since 2001 and a pay-as-you-throw program during 2005, guaranteeing more than the minimum level of recycling required by the Italian legislation. Structured questionnaires were administered to a sample of 500 people in 2010. Chi-square tests of independence were applied to state whether the differences were statistically significant (5%). About 90% of the sample stated that the success of the separate collection program was due to either the citizens and local authority or only the local authority, highlighting the leading role of the local authority and confirming that trust is the key to any social program success. The registered level of knowledge was better than that of nearby university students and citizens. The higher the education level, the greater the level of knowledge was.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Molecular Assembly-Induced Charge Transfer for Programmable Functionalities

The donor–acceptor interface within molecular charge transfer (CT) solids plays a vital role in the hybridization of molecular orbitals to determine their carrier transport and electronic delocalization. In this study reported herein, we demonstrate molecular assembly-driven bilayer and crystalline solids, consisting of electron donor dibenzotetrathiafulvalene (DBTTF) and acceptor C 60 , in which interfacial engineering-induced CT degree control is a key parameter for tuning its optical, electronic, and magnetic performance. Compared to the DBTTF/C 60 bilayer structure, the DBTTFC 60 cocrystalline solids show a stronger degree of charge transfer for broad CT absorption and a large dielectric constant. In addition, the DBTTFC 60 cocrystals exhibit distinct CT arrangement-driven anisotropic electron mobility and spin characteristics, which further enables the development of high-penetration and high-energy $γ$-ray photodetectors. The results presented in this paper provide a basis for the design and control of molecular charge transfer solids, which facilitates the integration of such materials into molecular electronics.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

An Acrylonitrile–Butadiene–Lignin Renewable Skin with Programmable and Switchable Electrical Conductivity for Stress/Strain-Sensing Applications

We report an approach for programming electrical conductivity of a bio-based leathery skin devised with a layer of 60 nm metallic nanoparticles. Lignin-based renewable shape-memory materials were made, for the first time, to program and restore the materials’ electrical conductivity after repeated deformation up to 100% strain amplitude, at a temperature 60–115 °C above the glass transition temperature (T g ) of the rubbery matrix. We cross-linked lignin macromolecules with an acrylonitrile–butadiene rubbery melt in high quantities ranging from 40 to 60 wt % and processed the resulting thermoplastics into thin films. Chemical and physical networks within the polymeric materials significantly enhanced key characteristics such as mechanical stiffness, strain fixity, and temperature-stimulated recovery of shape. The branched structures of the guaiacylpropane-dominant softwood lignin significantly improve the rubber’s T g and produced a film with stored and recoverable elastic work density that was an order of magnitude greater than those of the neat rubber and of samples made with syringylpropane-rich hardwood lignin. The devices could exhibit switching of conductivity before and after shape recovery.

36 MATERIALS SCIENCE↗