Publications

Results 4901–5000 of 99,299

Search results

Jump to search filters

On-Line Waste Library V4.0 Supporting Information

Price, Laura L.

The On-Line Waste Library is a website that contains information regarding United States Department of Energy-managed high-level waste, spent nuclear fuel, and other wastes that are likely candidates for deep geologic disposal, with links to supporting documents for the data. This report provides supporting information for the data for which an already published source was not available.

More Details
TYPE SAND Report YEAR 2022
DOIOSTI

Exploring the Basic Physical Mechanisms of Cathode- and Anode-Initiated High-Voltage Surface Flashover

IEEE Transactions on Plasma Science

Brooks, William; Clark, Raimi; Young, Jacob; Hopkins, Matthew M.; Dickens, James; Neuber, Andreas

Surface flashover in vacuum imposes a substantial physical limit on modern, large-scale pulsed power. One of the ramifications is a minimum size requirement for new machines, which in itself becomes a hard barrier to the modernization and improvement of existing infrastructure. Pulsed power topologies require the physical mechanisms of both anode- and cathode-initiated flashover to be considered. Originally, the geometrical implications of field emission at the cathode triple junction (CTJ) motivated the usage of configurations that avoid electrons impinging on the insulating material. This will largely suppress the cathode-initiated flashover, which is best described by the secondary electron avalanche mechanism, gas desorption, and final breakdown in the desorbed gas. It depends on the cascade growth of a conducting plasma along the length of the insulator from the cathode. Mitigating the cathode-initiated flashover typically comes at the cost of a significant field enhancement at the anode triple junction (ATJ). In a typical implementation, the anode field may be three times higher than the cathode field for a given voltage, making the corresponding anode-initiated flashover much more common than otherwise. In the case of pulsed, anode-initiated flashover, experimental evidence suggests that charge is directly extracted from the insulator resulting in the insulator taking on a net positive charge advancing the anode potential. Along with accompanying gas desorption from the surface, the potential will then propagate from the anode toward the cathode until the effective length of the gap is sufficiently reduced to support flashover. The underlying physical mechanisms of cathode- and anode-directed flashover are discussed in light of previously gathered experimental data and recent experiments with pulsed, high-gradient, anode-initiated flashover.

More Details
TYPE Journal Article YEAR 2022
DOIOSTIScopus

Mini-DAQ: A lightweight, low-cost, high resolution, data acquisition system for wave energy converter testing

HardwareX

Bosma, Bret; Coe, Ryan G.; Bacelli, Giorgio; Brekken, Ted; Gunawan, Budi

As part of the development process, scaled testing of wave energy converter devices are necessary to prove a concept, study hydrodynamics, and validate control system approaches. Creating a low-cost, small, lightweight data acquisition system suitable for scaled testing is often a barrier for wave energy converter developers’ ability to test such devices. This paper outlines an open-source solution to these issues, which can be customized based on specific needs. This will help developers with limited resources along a path toward commercialization.

More Details
TYPE Conference Poster YEAR 2022
DOIOSTIScopus

A model for K-shell x-ray yield from magnetic implosions at Sandia's Z machine

Physics of Plasmas

Schwarz, Jens; Vesey, Roger A.; Ampleford, David J.; Schaeuble, Marc-Andre S.; Giuliani, J.L.; Esaulov, A.; Dasgupta, A.; Jones, Brent M.

A zero-dimensional magnetic implosion model with a coupled equivalent circuit for the description of an imploding nested wire array or gas puff is presented. Circuit model results have been compared with data from imploding stainless steel wire arrays, and good agreement has been found. The total energy coupled to the load, E j × B, has been applied to a simple semi-analytic K-shell yield model, and excellent agreement with previously reported K-shell yields across all wire array and gas puff platforms is seen. Trade space studies in implosion radius and mass have found that most platforms operate near the predicted maximum yield. In some cases, the K-shell yield may be increased by increasing the mass or radius of the imploding array or gas puff.

More Details
TYPE Journal Article YEAR 2022
DOIOSTIScopus

Comparison of exponential integrators and traditional time integration schemes for the shallow water equations

Applied Numerical Mathematics

Eldred, Christopher; Brachet, Matthieu; Debreu, Laurent

The time integration scheme is probably one of the most fundamental choices in the development of an ocean model. In this paper, we investigate several time integration schemes when applied to the shallow water equations. This set of equations is accurate enough for the modeling of a shallow ocean and is also relevant to study as it is the one solved for the barotropic (i.e. vertically averaged) component of a three dimensional ocean model. We analyze different time stepping algorithms for the linearized shallow water equations. High order explicit schemes are accurate but the time step is constrained by the Courant-Friedrichs-Lewy stability condition. Implicit schemes can be unconditionally stable but, in practice lack accuracy when used with large time steps. In this paper we propose a detailed comparison of such classical schemes with exponential integrators. The accuracy and the computational costs are analyzed in different configurations.

More Details
TYPE Journal Article YEAR 2022
DOIOSTIScopus

V31 Test Report

Stofleth, Jerome H.; Crocker, Robert W.; Tribble, Megan K.

The V31 containment vessel was procured by the US Army Recovered Chemical Material Directorate (RCMD) as a third - generation EDS containment vessel. It is the fifth EDS vessel to be fabricated under Code Case 2564 of the 2019 ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels. The explosive rating for the vessel, based on the code case, is twenty-four (24) pounds TNT - equivalent for up to 1092 detonations. This report documents the results of explosive tests that were performed on the vessel at Sandia National Laboratories in Albuquerque, New Mexico to qualify the vessel for field operations use. There were three design basis configurations for qualification testing. Qualification test (1) consisted of a simulated M55 rocket motor and warhead assembly of 24lbs of Composition C-4 (30 lb TNT equivalent). This test was considered the maximum load case, based on modeling and simulation methods performed by Sandia prior to the vessel design phase. Qualification test (2) consisted of a regular, right circular cylinder, unitary charge, located central to the vessel interior of 19.2 lb of Composition C-4 (24 lb TNT equivalent). Qualification test (3) consisted of a 12-pack of regular, right circular cylinders of 2 lb each, distributed evenly inside the vessel (totaling 19.2 lb of C-4, or 24 lb TNT equivalent). All vessel acceptance criteria were met.

More Details
TYPE SAND Report YEAR 2022
DOIOSTI

Magnetized High-Energy-Density Plasma Experiments at MIT

Hare, Jack; Datta, Rishabh; Varnish, Thomas; Lebedev, Sergey; Jerry, Chittenden; Crilly, Aidan; Halliday, Jack; Russell, Danny; Chandler, Katherine M.; Fox, Will; Hantao, Ji; Myers, Clayton; Aragon, Carlos; Jennings, Christopher A.; Ampleford, David J.; Hansen, Stephanie B.; Yager-Elorriaga, David A.; Harding, Eric H.; Shipley, Gabriel A.; Harmon, Roger; Gonzalez, Josue; Molina, Leo

Abstract not provided.

More Details
TYPE Conference Presentation YEAR 2022
DOIOSTI

A Liquid Stratification Model to Predict Failure in Thermally Damaged EBW Detonators

Propellants, Explosives, Pyrotechnics

Hobbs, Michael L.; Coronel, Stephanie A.

In previous work, commercially available downward facing exploding bridgewire detonators (EBWs) were exposed to elevated temperatures. These detonators were then initiated using a firing set which discharged a high amplitude short duration electrical pulse into a thin gold bridgewire. Responses of the detonators were measured using photonic doppler velocimetry (PDV) and high-speed photography. A time delay of 2 μs between EBW initiation and first movement of an output flyer separated operable detonators from inoperable detonators or duds. In the current work, we propose a simple method to determine detonator operability from the calculated state of the detonator at the time the firing set is initiated. The failure criterion is based on the gap distance between the exploding bridgewire (EBW) and the adjacent initiating explosive within the detonator which is low-density pentaerythritol tetranitrate (PETN) that melts between 413–415 K (140–142 °C). The gap forms as PETN melts and flows to the bottom of the input pellet. Melting of PETN is modeled thermodynamically as an energy sink using a normal distribution spread over a temperature range between the onset temperature of 413 K and the ending temperature of 415 K. The extent of the melt is determined from the average temperature of the PETN. The PETN liquid is assumed to occupy the interstitial gas volume in the lower part of the input pellet. The vacated volume from the relocated liquid forms the gap between the EBW and the PETN. The remaining sandwiched layer consists of solid PETN particles and gas filling interstitial volume. We predict that a threshold gap between 17–27 μm separates properly functioning detonators from duds.

More Details
TYPE Journal Article YEAR 2022
DOIOSTIScopus

Reconfiguration of the Respiratory Tract Microbiome to Prevent and Treat Burkholderia Infection

Branda, Steven; Collette, Nicole; Aiosa, Nicole; Garg, Neha; Mageeney, Catherine M.; Williams, Kelly P.; Phillips, Ashlee; Hern, Kelsey; Arkin, Adam; Ricken, Bryce; Wilde, Delaney; Dogra, Sahiba; Humphrey, Brittany; Poorey, Kunal; Courtney, Colleen

New approaches to preventing and treating infections, particularly of the respiratory tract, are needed. One promising strategy is to reconfigure microbial communities (microbiomes) within the host to improve defense against pathogens. Probiotics and prebiotics for gastrointestinal (GI) infections offer a template for success. We sought to develop comparable countermeasures for respiratory infections. First, we characterized interactions between the airway microbiome and a biodefense-related respiratory pathogen (Burkholderia thailandensis; Bt), using a mouse model of infection. Then, we recovered microbiome constituents from the airway and assessed their ability to re-colonize the airway and protect against respiratory Bt infection. We found that microbiome constituents belonging to Bacillus and related genuses frequently displayed colonization and anti-Bt activity. Comparative growth requirement profiling of these Bacillus strains vs Bt enabled identification of candidate prebiotics. This work serves as proof of concept for airway probiotics, as well as a strong foundation for development of airway prebiotics.

More Details
TYPE SAND Report YEAR 2022
DOIOSTI

High-Sensitivity rf Detection Using an Optically Pumped Comagnetometer Based on Natural-Abundance Rubidium with Active Ambient-Field Cancellation

Physical Review Applied

Bainbridge, Jonathan E.; Claussen, Neil; Iivanainen, Joonas; Schwindt, Peter D.

To detect a specific radio-frequency (rf) magnetic field, rf optically pumped magnetometers (OPMs) require a static magnetic field to set the Larmor frequency of the atoms equal to the frequency of interest. However, unshielded and variable magnetic field environments (e.g., an rf OPM on a moving platform) pose a problem for rf OPM operation. Here, we demonstrate the use of a natural-abundance rubidium vapor to make a comagnetometer to address this challenge. Our implementation builds upon the simultaneous application of several OPM techniques within the same vapor cell. First, we use a modified implementation of an OPM variometer based on 87Rb to detect and actively cancel unwanted external fields at frequencies 60Hz using active feedback to a set of field control coils. We exploit this stabilized field environment to implement a high-sensitivity rf magnetometer using 85Rb. Using this approach, we demonstrate the ability to measure rf fields with a sensitivity of approximately 9fTHz-1/2 inside a magnetic shield in the presence of an applied field of approximately 20μT along three mutually orthogonal directions. This demonstration opens up a path toward completely unshielded operation of a high-sensitivity rf OPM.

More Details
TYPE Journal Article YEAR 2022
DOIOSTIScopus

Combined thermographic phosphor and digital image correlation (TP + DIC) for simultaneous temperature and strain measurements

Strain

Jones, E.M.C.; Jones, A.R.; Winters, C.

Thermographic phosphors (TP) are combined with stereo digital image correlation (DIC) in a novel diagnostic, TP + DIC, to measure full-field surface strains and temperatures simultaneously. The TP + DIC method is presented, including corrections for nonlinear CMOS camera detectors and generation of pixel-wise calibration curves to relate the known temperature to the ratio of pixel intensities between two distinct wavelength bands. Additionally, DIC is employed not only for strain measurements but also for accurate image registration between the two cameras for the two-colour ratio method approach of phosphoric thermography. TP + DIC is applied to characterize the thermo-mechanical response of 304L stainless steel dog bones during tensile testing at different strain rates. The dog bones are patterned for DIC with Mg3F2GeO4:Mn (MFG) via aerosol deposition through a shadow mask. Temperatures up to 425°K (150°C) and strains up to 1.0 mm/mm are measured in the localized necking region, with conservative noise levels of 10°K and 0.01 mm/mm or less. Finally, TP + DIC is compared to the more established method of combining infrared (IR) thermography with DIC (IR + DIC), with results agreeing favourably. Three topics of continued research are identified, including cracking of the aerosol-deposited phosphor DIC features, incomplete illumination for pixels on the border of the phosphor features, and phosphor emission evolution as a function of applied substrate strain. This work demonstrates the combination of phosphor thermography and DIC and lays the foundation for further development of TP + DIC for testing in combined thermo-mechancial environments.

More Details
TYPE Journal Article YEAR 2022
DOIOSTIScopus
Results 4901–5000 of 99,299
Results 4901–5000 of 99,299