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At least 37 records · Page 2

An SDO/AIA-Observed Filament Eruption Triggered by a Lid-Removal Onset Mechanism

An eruption of a solar filament often presages the onset of a more general solar eruption, often leading to a solar flare and coronal mass ejection (CME). Among the mechanisms suggested for triggering eruptions are flux cancellation, flux emergence, tether‐cutting reconnection, and breakout reconnection. Here we present an example of a filament eruption due to a different trigger mechanism, which we call ``lid removal,'' whereby a magnetic structure overlying the filament is removed by a preceding adjacent eruption, rendering MHD unstable the magnetic system containing the filament and resulting in the subsequent eruption of the filament. This filament eruption occurred on 23 Jan 2013, and was well‐seen in SDO/AIA 193 Ang images. Prior to its eruption the filament was at an approximately constant height above the solar surface for approx. 4 hours, before smoothly lifting off. Evidence for the overlying "lid'' field was difficult to discern in 193 Ang images, but was apparent in hotter coronal images, such as SDO/AIA 335. Removal of the lid field was due to an eruption of that field visible in the hotter‐corona images. In this way, the lid‐removal filament‐eruption mechanism is similar to recent observations of connected or cascading eruptions originating from magnetically‐linked locations.

Sterling, Alphonse C.↗

An SDO/AIA-Observed Filament Eruption Triggered by a Lid-Removal Onset Mechanism

An eruption of a solar filament often presages the onset of a more general solar eruption, often leading to a solar flare and coronal mass ejection (CME). Among the mechanisms suggested for triggering eruptions are flux cancellation, flux emergence, tether-cutting reconnection, and breakout reconnection. Here we present an example of a filament eruption due to a different trigger mechanism, which we call "lid removal,'' whereby a magnetic structure overlying the filament is removed by a preceding adjacent eruption, rendering MHD unstable the magnetic system containing the filament and resulting in the subsequent eruption of the filament. This filament eruption occurred on 23 Jan 2013, and was well-seen in SDO/AIA 193 Ang images. Prior to its eruption the filament was at an approximately constant height above the solar surface for approx 4 hours, before smoothly lifting off. Evidence for the overlying "lid'' field was difficult to discern in 193 Ang images, but was apparent in hotter coronal images, such as SDO/AIA 335. Removal of the lid field was due to an eruption of that field visible in the hotter‐corona images. In this way, the lid‐removal filament‐eruption mechanism is similar to recent observations of connected or cascading eruptions originating from magnetically‐linked locations.

Sterling, Alphonse C.↗

Drum lid removal tool

A tool for removing the lid of a metal drum wherein the lid is clamped over the drum rim without protruding edges, the tool having an elongated handle with a blade carried by an angularly positioned holder affixed to the midsection of the handle, the blade being of selected width to slice between lid lip and the drum rim and, when the blade is so positioned, upward motion of the blade handle will cause the blade to pry the lip from the rim and allow the lid to be removed.

Pella, Bernard M↗

Fluor Idaho Technical Investigation-ARP V Lid Ejection Reactants and Mechanism - 19521

In April 2018, four 208.2-L (55-gal) drums containing transuranic waste at the Idaho National Laboratory Site became over-pressurized, resulting in lid ejection and expulsion approximately 50% of the contents. The parent drums were part of a retrieval effort and were exhumed from a portion of Subsurface Disposal Area Pits 11 and 12 beginning in 1974 and ending in 1978. Drums were later retrieved from the cargo containers, characterized using real-time radiography and nondestructive assay, and opened. The contents were visually inspected and repackaged into new 'daughter' drums within the Accelerated Retrieval Project V facility. Lid ejection occurred 7-12 hours after repackaging. The lid ejections were accompanied by significant heat generation. Empirical evidence of heat generation was observed in each reacted drum. The heat generated was sufficient to warp the high-density polyethylene liner (< 122 to 137 deg. C) in three of the drums and char the drum paint (∼400 deg. C) on one drum. To determine the potential reactant(s), a comprehensive chemical analysis was performed by two independent laboratories, Southwest Research Institute and Savannah River National Laboratory, on the reacted drum contents, ejected drum material, and related drums. A comprehensive chemical compatibility analysis was performed, and the most likely reactant(s) were identified. The oxidation of depleted uranium was the source of the heat generation. The presence of depleted uranium in the daughter drums and its chemical behavior (reactive properties and lack of visual indicators during packaging) are consistent with the event. The heat generated was sufficient to accelerate secondary chemical reactions leading to significant gas formation sufficient to generate pressures well in excess of the pressures needed to eject the lid and contents. These reactions fall into two categories: (1) simple volatilization of organics and water present in the drum and (2) hydrolysis of beryllium carbide, which generated significant quantities of methane gas. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Standard Waste Box Lid Screw Removal Option Testing

This report provides results from test work conducted to resolve the removal of screws securing the standard waste box (SWB) lids that hold the remediated nitrate salt (RNS) drums. The test work evaluated equipment and process alternatives for removing the 42 screws that hold the SWB lid in place. The screws were secured with a red Loctite thread locker that makes removal very difficult because the rivets that the screw threads into would slip before the screw could be freed from the rivet, making it impossible to remove the screw and therefore the SWB lid.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Instrumented Lid: Full Instrumentation System Testing

This report describes full system testing of an instrumentation system for the monitoring of aluminum clad spent nuclear fuel (ASNF). The requirements for this system were laid out in a previous document, with respect to former studies, and the details of project actualization were reported. The reader is directed to these references for more background information. In short, a team composed of personnel from Savannah River National Laboratory (SRNL) and Idaho National Laboratory have been tasked with the design and fabrication of an instrumented assembly for remote sampling, monitoring, and radiation testing (SMART) for demonstration and surveillance of the dry storage environment and conditions of ASNF in a DOE standardized canister. SRNL proposed the fabrication of two systems to accomplish this goal: 1) an instrumentation system consisting of gas and particle collection, temperature, humidity, pressure, and radiation monitoring; and 2) a lid assembly consisting of a custom-designed lid and hat, together with a custom fuel basket. The corresponding instrumentation system is shown in the piping and instrumentation diagram. The individual functionality tests of the instrument system sensor components were performed, and the results were reported in the report “Instrumented Lid- System Functionality Testing.” Savannah River National Laboratory, September 1, 2019.7 The sensor components of instrumentation system have been mounted and tested in-line with a 6” diameter test canister, and the results are reported in this document.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Adjustable Lid Aids Silicon-Ribbon Growth

Closely-spaced crucible cover speeds up solidification. Growth rate of dendritic-web silicon ribbon from molten silicon increased by controlling distance between crucible susceptor lid and liquid/solid interface. Lid held in relatively high position when crucible newly filled with chunks of polycrystalline silicon. As silicon melts and forms pool of liquid at lower level, lid gradually lowered.

Mchugh, J. P.↗

Mobile Lid Convection Beneath Enceladus' South Polar Terrain

Enceladus' south polar region has a large heat flux, 55-110 milliwatts per square meter (or higher), that is spatially associated with cryovolcanic and tectonic activity. Tidal dissipation and vigorous convection in the underlying ice shell are possible sources of heat; however, prior predictions of the heat flux carried by stagnant lid convection range from F(sub conv) ~15 to 30 milliwatts per square meter, too low to explain the observed heat flux. The high heat flux and increased cryovolcanic and tectonic activity suggest that near-surface ice in the region has become rheologically and mechanically weakened enough to permit convective plumes to reach close to the surface. If the yield strength of Enceladus' lithosphere is less than ~1-10 kPa, convection may instead occur in the mobile lid" regime, which is characterized by large heat fluxes and large horizontal velocities in the near-surface ice. I show that model ice shells with effective surface viscosities between 10(exp 16) and 10(exp 17) Pa s and basal viscosities between 10(exp 13) and 10(exp 15) Pa s have convective heat fluxes comparable to that observed by the Cassini Composite Infrared Spectrometer. If this style of convection is occurring, the south polar terrain should be spreading horizontally with v~1-10 millimeter per year and should be resurfaced in ~0.1-10 Ma. On the basis of Cassini imaging data, the south polar terrain is ~0.5 Ma old, consistent with the mobile lid hypothesis. Maxwell viscoelastic tidal dissipation in such ice shells is not capable of generating enough heat to balance convective heat transport. However, tidal heat may also be generated in the near-surface along faults as suggested by Nimmo et al. and/or viscous dissipation within the ice shell may occur by other processes not accounted for by the canonical Maxwell dissipation model.

Barr, Amy C.↗

LID and LeTID Impacts to PV Module Performance and System Economics: Draft Analysis

This webinar is a technical review of the measurements and causes of BO LID, UV LID and LeTID, as well as modeling their impacts to PV project financial metrics. We will first review how Boron-Oxygen complexes form and detail the range of impacts to PV module power ratings over time and across climates. Similarly, we will also discuss the measurements and extent of UV LID over time and across climates. Then, we will demonstrate a methodology for translating these effects to pro forma cash flow models and their impacts to PV project financial returns and levelized cost of electricity (LCOE). We will conclude with estimates of the value of solutions to these degradation mechanisms.

41 EE - Solar Energy Technologies Office (EE-4S)↗

An Open-Source Python Library for Modeling LETID and LID in Silicon Solar Cells and Wafers

This poster demonstrates an (in development) open-source software library, written in python, to aid in modeling and understanding light- and elevated temperature-induced degradation (LETID) and boron-oxygen light-induced degradation (B-O LID) in silicon solar cells and wafers. We discuss the underlying equations and necessary input parameters for constructing realistic models. We demonstrate several use cases for the library, including modeling LETID progression in scenarios like indoor, accelerated tests and outdoor field deployment. We also demonstrate using the library to model B-O LID, and we demonstrate using the library to model degradation in passivated wafers, rather than solar cells.

LETID↗

Understanding Microscopic Mechanisms of LeTID and LID and their Unifying Features by Electron Paramagnetic Resonance

LID degradation involves not only creation of ~ 10^12 cm^-3 recombination centers, but also ~ 10^16 cm^-3 shallow negative-U traps. In Ga-doped Si, LID EPR defects don't appear, but some traps are still created. LeTID: Si DB and H-hyperfine EPR signatures. We postulate that the defect responsible for LeTID is a partially hydrogenated (multivacancy) with a Si dangling bond and H in the vicinity. O involvement is possible yet unclear. We prove that H is related to the structure of the LeTID defect with isotope experiments and its EPR signal is comparable and linear with the Si DB signal upon LeTID degradation. Working on simulating these results with DFT to obtain more detailed defect structure.

Cz Si↗

Los Alamos National Laboratory Lessons Learned for Fiscal Year 2018: SAVY-4000 Lid Bar Stock Issue

During acceptance testing at Nuclear Filter Technologies (NFT) in May, 2018 of a batch of 150 SAVY-4000 containers (3 Qt), 89 containers were rejected due to failing and higher than normal helium leakage test results (see attachment NC#18-033). A total of 56 of those rejected failed the maximum allowed helium leakage rate criterion of 1.0E-05 std cc/sec specified in 55Y-002926 Rev. G, SAVY-4000 fabrication Specification. In addition, 33 containers were also rejected by the manufacturer with helium leakage rates measured between 1.0E-05 and 1.0E-06 std cc/sec (NFT NC# 18-033) because the containers were manufactured from the same lot of base material and the helium leakage rates were outside of the expected range. Upon discovery of the helium leakage test failures of the 3 Qt SAVY’s, NFT pulled the inventory of containers that failed the helium leakage tests and performed a detailed inspection of the lid assemblies. Small voids were discovered by visual inspection on opposing sides of the lids.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Overview of LIDS Docking Seals Development

GRC is supporting JSC by developing LIDS main interface seals Seal development and testing is occurring at both sub-scale and full-scale levels: a) Small-scale tests performed to define seal materials and evaluate exposure to space environments. b) Medium-scale testing: 1) Permits evaluation of candidate seal designs at faster pace than for full-scale seals. 2) Leak rates and loads can be scaled up to full-scale for indication of seal performance. c) Full-scale test rigs used for seal development and flight qualification tests and to assess on-orbit anomalies if needed. GRC responsible for delivering flight hardware seals to JSC approx.2013 for integration into LIDS flight units.

Dunlap, Patrick↗

Overview of LIDS Docking Seals Development

NASA is developing a new docking system to support future space exploration missions to low-Earth orbit, the Moon, and Mars. This mechanism, called the Low Impact Docking System (LIDS), is designed to connect pressurized space vehicles and structures including the Crew Exploration Vehicle, International Space Station, and lunar lander. NASA Glenn Research Center (GRC) is playing a key role in developing the main interface seal for this new docking system. These seals will be approximately 147 cm (58 in.) in diameter. GRC is evaluating the performance of candidate seal designs under simulated operating conditions at both sub-scale and full-scale levels. GRC is ultimately responsible for delivering flight hardware seals to NASA Johnson Space Center around 2013 for integration into LIDS flight units.

Dunlap, Pat↗

Physics of Failure Analysis of Xilinx Flip Chip CCGA Packages: Effects of Mission Environments on Properties of LP2 Underfill and ATI Lid Adhesive Materials

The Xilinx Virtex 4QV and 5QV (V4 and V5) are next-generation field-programmable gate arrays (FPGAs) for space applications. However, there have been concerns within the space community regarding the non-hermeticity of V4/V5 packages; polymeric materials such as the underfill and lid adhesive will be directly exposed to the space environment. In this study, reliability concerns associated with the non-hermeticity of V4/V5 packages were investigated by studying properties and behavior of the underfill and the lid adhesvie materials used in V4/V5 packages.

Suh, Jong-ook↗

New Aspects of a Lid-Removal Mechanism in the Onset of a SEP-Producing Eruption Sequence

We examine a sequence of two ejective eruptions from a single active region on 2012 January 23, using magnetograms and EUV images from SDO/HMI and SDO/AIA, and EUV images from STEREO. Cheng et al. (2013) showed that the first eruption's ("Eruption 1'') flux rope was apparent only in "hotter'' AIA channels, and that it removed overlying field that allowed the second eruption (``Eruption 2'') to begin via ideal MHD instability; here we say Eruption 2 began via a ``lid removal'' mechanism. We show that during Eruption-1's onset, its flux rope underwent ``tether weakening'' (TW) reconnection with the field of an adjacent active region. Standard flare loops from Eruption 1 developed over Eruption-2's flux rope and enclosed filament, but these overarching new loops were unable to confine that flux rope/filament. Eruption-1's flare loops, from both TW reconnection and standard-flare-model internal reconnection, were much cooler than Eruption-2's flare loops (GOES thermal temperatures of approx. 9 MK compared to approx. 14 MK). This eruption sequence produced a strong solar energetic particle (SEP) event (10 MeV protons, >10(exp 3) pfu for 43 hrs), apparently starting when Eruption-2's CME blasted through Eruption-1's CME at 5-10 R_s. This occurred because the two CMEs originated in close proximity and in close time sequence: Eruption-1's fast rise started soon after the TW reconnection; the lid removal by Eruption-1's ejection triggered the slow onset of Eruption 2; and Eruption-2's CME, which started approx. 1 hr later, was three times faster than Eruption-1's CME.

Sterling, Alphonse C.↗

Physics of failure analysis of Xilinx Flip Chip CCGA packages: effects of mission environments on properties of LP2 underfill and ATI lid adhesive materials

The Xilinx Virtex 4QV and 5QV (V4 and V5) are next-generation field-programmable gate arrays (FPGAs) for space applications. However, there have been concerns within the space community regarding the non-hermeticity of V4/V5 packages; polymeric materials such as the underfill and lid adhesive will be directly exposed to the space environment. In this study, reliability concerns associated with the non-hermeticity of V4/V5 packages were investigated by studying properties and behavior of the underfill and the lid adhesvie materials used in V4/V5 packages.

Suh, Jong-ook↗

LANL Interactive Display (LID) - DC Vault Updates and FY24 proposals

The LANL Interactive Display (LID) is an interactive touchscreen with a custom-built application designed to provide a geographic-based, virtual tour of the Laboratory’s organizations, facilities, programs, products, and capabilities. The Display is mounted on a portable stand and displayed in the classified vault of the Forrestal Building in Washington, D.C. The October 2023 updates include the latest inputs, including the addition of Nuclear Security Enterprise (NSE) information. Other major upgrades are detailed below.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗