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At least 1,729 records · Page 96

Methods of preparing flexible photovoltaic devices using epitaxial liftoff, and preserving the integrity of growth substrates used in epitaxial growth

There is disclosed methods of making photosensitive devices, such as flexible photovoltaic (PV) devices, through the use of epitaxial liftoff. Also described herein are methods of preparing flexible PV devices comprising a structure having a growth substrate, wherein the selective etching of protective layers yields a smooth growth substrate that us suitable for reuse.

14 SOLAR ENERGY↗

Determining Remaining Useful Life of Aging Cables in Nuclear Power Plants using Non-destructive Evaluation

License renewal of existing nuclear power plants (NPPs) to extend operation from 40 to 60 to 80 years will require effective aging management programs for the 100’s of kilometers of electric power, control and instrumentation cables installed in each plant. Degradation of jacket, insulation and other cable components can reduce the ability of cables to withstand design-basis accidents. The groundwork for a research and development roadmap to address aging cable management in NPPs was laid at a July 2012 workshop1 that brought together subject matter experts from the U.S. Nuclear Regulatory Commission (NRC), the U.S. Department of Energy (DOE) national laboratories, the Electric Power Research Institute (EPRI), universities, and cable manufacturers and inspectors. The most common nondestructive evaluation (NDE) methods for gauging cable status include indentation and visual inspection. These methods are limited to evaluation of the surface easily accessed cable assemblies. Other current methods (such as time and frequency domain analysis, inductance and capacitance measurements, tan d, etc.) provide flaw detection, but are not predictive. The workshop identified the need to advance and develop new NDE methods to enable in-situ cable condition assessment. Key chemical, physical, and electrical indicators of cable aging with exposure to heat, radiation, moisture, chemicals, and mechanical stress need to be determined. Finally, models correlating the key cable indicators with NDE signals need to be developed that can aging cable remaining useful life.

NDE, Nuclear Cables, Polymer Aging↗

Apparatus for use in a directional-neutron detector, directional-neutron detectors and methods of use thereof

An apparatus for used in a directional-neutron detector is disclosed. The apparatus comprises a structure having a plurality of parallel active channels separated by inactive regions. The plurality of active channels is filled with scintillating material. The scintillating material is configured to emit light in response to neutron scattering. The scintillating material may be neutron-gamma discriminating. The scintillating material may be sealed in the plurality of active channels. The seal is disposed on respective ends of the plurality of active channels. Directional-neutron detectors are also disclosed having the structure.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Conducting coatings for anodes, methods of making and using same, and uses thereof

Conducting coatings disposed on a metal member. The conducting coatings may have a desired texture and provide homoepitaxial or heteroepitaxial coating of an electrodeposited layer. A conducting coating may be formed by applying a shear force during deposition of the conducting coating. The conducting coatings may be used in anodes of various electrochemical devices. A conducting coating, which may be part of an electrochemical device, may have an electrochemically deposited layer disposed on at least a portion of a surface of the conducting coating. The electrochemically deposited layer may be reversibly electrochemically deposited.

Archer, Lynden A.↗

Impact of Using Cross Sections Versus Recipes in Transition Fuel Cycle Analysis using ORION

ORION, a nuclear fuel cycle simulator developed at the UK National Nuclear Laboratory (NNL), is designed to simulate the operations of general nuclear fuel cycles, including once-through, limited recycle, and continuous recycle fuel cycle options. ORION can simulate the full range of nuclear-related facilities e.g. interim and long-term storage locations, fabrication and enrichment plants, reprocessing facilities, and reactors. It can track over 2,500 nuclides and can model decay and in-reactor irradiation. Based on ORION's ability to track the full isotopic mass flow between fuel cycle facilities (with or without decay), it is possible to model all of the necessary nuclide production and destruction routes. This is essential when calculating accurate spent nuclear fuel (SNF) compositions and associated metrics (e.g., decay heat and radioactivity). When modeling the transition from the current once through US fuel cycle to an alternative fuel cycle, it is important to accurately model the US pressurized water reactor (PWR) discharged SNF composition while minimizing the computational time. This paper discusses two rapid methods used to model the US PWR discharged SNF-fixed recipes versus cross sections-and it discusses the differences between the results from these two methods in relation to fuel cycle transition analysis. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Global parameterization and validation of a two-leaf light use efficiency model for predicting gross primary production across FLUXNET sites: TL-LUE Parameterization and Validation

We present the first extended validation of satellitemicrowave (MW) liquidwater path (LWP) for low nonprecipitating clouds, from four operational sensors, against ship-borne observations from a three-channel MW radiometer collected along ship transects over the northeast Pacific during May–August 2013. Satellite MW retrievals have an overall correlation of 0.84 with ship observations and a bias of 9.3 g/m2. The bias for broken cloud scenes increases linearly with water vapor path and remains below 17.7 g/m2. In contrast, satelliteMWLWP is unbiased in overcast scenes with correlations up to 0.91, demonstrating that the retrievals are accurate and reliable under these conditions. Satellite MW retrievals produce a diurnal cycle amplitude consistent with ship-based observations (33 g/m2). Observations taken aboard extended ship cruises to evaluate not only satellite MW LWP but also LWP derived from visible/infrared sensors offer a new way to validate this important property over vast oceanic regions.

Zhou, Yanlian↗

Using an explicit emission tagging method in global modeling of source‐receptor relationships for black carbon in the Arctic: Variations, sources, and transport pathways

Abstract We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source‐region‐resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions provides a physically consistent and computationally efficient approach to establish source‐receptor relationships and transport pathways. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region‐dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near‐linear dependence on their respective contributions to the burden. Arctic BC concentrations, deposition, and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic BC burden, but has much less impact on lower‐level concentrations and deposition. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per‐emission efficiency is much higher than for non‐Arctic sources. The interannual variability (1996–2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source dependent. Global BC forcing‐per‐burden efficiency also increases primarily due to changes in BC vertical distributions.

Wang, Hailong↗

Stress distribution during cold compression of a quartz aggregate using synchrotron X-ray diffraction: Observed yielding, damage, and grain crushing

Herein, we report new experimental results that quantify the stress distribution within a quartz aggregate during pore collapse and grain crushing. The samples were probed with synchrotron X-ray diffraction as they were compressed in a multianvil deformation apparatus at room temperature from low pressure (tens of megapascal) to pressures of a few gigapascal. In such a material, stress is likely to concentrate at grain-to-grain contacts and vanish where grains are bounded by open porosity. Therefore, internal stress is likely to vary significantly from point to point in such an aggregate, and hence, it is important to understand both the heterogeneity and anisotropy of such variation with respect to the externally applied stress. In our quartz aggregate (grain size of ~4 μm), the measured diffraction peaks broaden asymmetrically at low pressure (tens of megapascal), suggesting that open pores are still a dominant characteristic of grain boundaries. In contrast, a reference sample of novaculite (a highly dense quartz polycrystal, grain size of ~6–9 μm) showed virtually no peak broadening with increasing pressure. In the quartz aggregate, we observed significant deviation in the pressure-volume curves in the range of P = 400–600 MPa. We suggest that this marks the onset of grain crushing (generally denoted as P* in the rock mechanic literature), which is commonly reported to occur in sandstones at pressures of this order, in general agreement with a Hertzian analysis of fracturing at grain contacts.

58 GEOSCIENCES↗