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Development of Membrane Platforms to Interrogate Host-Pathogen Interactions

Thatcher, Christine E.; Dupree, Amy K.; Webster, Elizabeth R.

Membrane fusion is a critical step in enveloped virus entry and infection; however, molecular understanding of enveloped virus entry and treatment options remain limited. In recent decades, advances in imaging have facilitated the development of methods to study single virus events and membrane organization providing insight towards entry mechanisms. Through these advances, membrane composition and organization have been shown to play a critical role in the entry process. This LDRD uses model membrane platforms and basic biophysics to investigate entry mechanisms of enveloped viruses and understand membrane-based delivery technologies. This team has established foundations for using membrane-based platforms and biophysical techniques at Sandia to characterize membrane fusion.

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TYPE SAND Report YEAR 2021
DOIOSTI

Report on High Energy Arcing Fault Experiments: Experimental Results from Open Box Enclosures

Lafleur, Chris; Glover, Austin M.; Clem, Paul; Winters, Caroline; Taylor, Gabriel; Salley, Mark H.; Putorti, Anthony; Cruz-Cabrera, Alvaro A.; Demosthenous, Byron; Martinez, Raymond

This report documents an experimental program designed to investigate High Energy Arcing Fault (HEAF) phenomena. The experiments focus on providing data to better characterize the arc to improve the prediction of arc energy emitted during a HEAF event. An open box experiment allow for direct observation of the arc, which allows diagnostic instrumentation to record the phenomenological data needed for better characterization of the arc energy source term. The data collected supports characterization of the arc and arc jet, enclosure breach, material loss, and electrical properties. These results will be used to better characterizing the hazard for improvements in fire probabilistic risk assessment (PRA) realism. The experiments were performed at KEMA Labs located in Chalfont, Pennsylvania. The experimental design, setup, and execution were completed by staff from the NRC, the National Institute of Standards and Technology (NIST), Sandia National Laboratories (SNL) and KEMA Labs. In addition, representatives from the Electric Power Research Institute (EPRI) observed some of the experimental setup and execution. The HEAF experiments were performed between August 22, 2020 and September 18, 2020 on near-identical 51 cm (20 in) cube metal boxes suspended from a Unistrut support structure. The three-phase arcing fault was initiated at the ends of the conductors oriented vertically and located at the center of the box. Either aluminum or copper conductors were used for the conductors. The low-voltage experiments used 1 000 volts AC, while the medium-voltage experiments used 6 900 volts AC consistent with other recently completed experiments. Durations of the experiment ranged from 1 s to 5 s with fault currents ranging from 1 kA to 30 kA. Real-time electrical operating conditions, including voltage, current and frequency, were measured during the experiments. Heat fluxes and incident energies were measured with plate thermometers, radiometers, and slug calorimeters at various locations around the electrical enclosures. The experiments were documented with normal and high-speed videography, infrared imaging and photography.

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TYPE Other Report YEAR 2021
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Turbo FRMAC Implementation of IAEA Radiological Assessment Methodologies for Nuclear and Radiological Emergencies: Ingestion Pathway and Skin and Thyroid Monitoring

Cochran, Lainy D.; Kalinowski, Autumn E.

This report documents the findings of an assessment of the Turbo FRMAC© software’s ability to implement International Atomic Energy Agency (IAEA) guidance for calculating operational intervention levels (OIL) for nuclear and radiological emergencies. This assessment is a continuation of previous work that considered IAEA OIL1 and OIL2 for evacuation and relocation protective actions. The IAEA OIL and U.S. Federal Radiological Monitoring and Assessment Center (FRMAC) derived response and intervention level methodologies were compared for ingestion and skin and thyroid monitoring pathways. This comparison revealed significant differences in IAEA versus FRMAC handling of these pathways, which precluded an assessment of Turbo FRMAC’s ability to implement the IAEA approach.

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TYPE SAND Report YEAR 2021
DOIOSTI

Report on High Energy Arcing Fault Experiments: Experimental Results from Low-Voltage Switchgear Enclosures

Lafleur, Chris; Taylor, Gabriel; Putorti Jr., Anthony D.; Salley, Mark H.

This report documents an experimental program designed to investigate High Energy Arcing Fault (HEAF) phenomena for low-voltage metal enclosed switchgear containing aluminum conductors. This report covers full-scale laboratory experiments using representative nuclear power plant (NPP) three-phase electrical equipment. Electrical, thermal, and pressure data were recorded for each experiment and documented in this report. This report covers experiments performed on two low-voltage switchgear units with each unit consisting of two vertical sections. The data collected supports characterization of the low-voltage HEAF hazard and these results will be used to support potential improvements in fire probabilistic risk assessment (PRA) methods. The experiments were performed at KEMA Labs located in Chalfont, Pennsylvania. The experimental design, setup, and execution were completed by staff from the NRC, the National Institute of Standards and Technology (NIST), Sandia National Laboratories (SNL) and KEMA. In addition, representatives from the Electric Power Research Institute (EPRI) observed some of the experimental setup and execution. The HEAF experiments were performed between August 26 and Augsut 29, 2019 on nearidentical Westinghouse Type DS low-voltage metal-enclosed indoor switchgear. The threephase arcing fault was initiated on the aluminum main bus or in select cases on the copper bus stabs near the breaker. These experiments used either nominal 480 volts AC or 600 volts AC. Durations of the experiments ranged from approximately 0.4 s to 8.3 s with fault currents ranging from approximately 9.2 kA to 19.3 kA. Real-time electrical operating conditions, including voltage, current and frequency, were measured during the experiments. Heat fluxes and incident energies were measured with plate thermometers, radiometers, and slug calorimeters at various locations around the electrical enclosures. Environmental measurements of breakdown, conductivity and electromagnetics were also taken. The experiments were documented with normal and high-speed videography, infrared imaging and photography. The results, while limited, indicated the difficulty in maintaining and sustaining low-voltage arcs on aluminum components of sufficient duration and at a single point as observed operating experience.

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TYPE Other Report YEAR 2021
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MELCOR Code Change History: Revision 18019 to 21402

Humphries, Larry L.; Beeny, Bradley A.; Haskin, Troy C.; Albright, Lucas I.; Gelbard, Fred M.

This document summarily provides brief descriptions of the MELCOR code enhancement made between code revision number 18019and 21440. Revision 18019 represents the previous official code release; therefore, the modeling features described within this document are provided to assist users that update to the newest official MELCOR code release, 21440. Along with the newly updated MELCOR Users’ Guide [2] and Reference Manual [3], users are aware and able to assess the new capabilities for their modeling and analysis applications.

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TYPE SAND Report YEAR 2021
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Attenuator, PC-2.92mm, Fixed (Proficiency Test Report; PT ID Number 6679665)

Sandoval, Ricky

The PSL has reviewed the documentation and data provided by NNSS–Livermore Operations with respect to this proficiency test. This proficiency test was performed to assess NNSS–Livermore Operations’ ability to perform scattering parameter calibrations. The level of documentation was satisfactory. On 12/28/2021, NNSS–Livermore Operations reported the data for the proficiency test conducted on the attenuator. NNSS–Livermore Operations performed this proficiency test using an Anritsu vector network analyzer, an electronic calibration module, and verification kit. The PSL used a Keysight vector network analyzer and mechanical calibration kit. The PSL results included in this proficiency test report were taken on June 23, 2020.

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TYPE Other Report YEAR 2021
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Magnetic field effects on laser energy deposition and filamentation in magneto-inertial fusion relevant plasmas

Physics of Plasmas

Lewis, Sean M.; Weis, Matthew R.; Speas, Christopher S.; Kimmel, Mark; Bengtson, Roger D.; Breizman, Boris; Geissel, Matthias; Gomez, Matthew R.; Harvey-Thompson, Adam J.; Kellogg, Jeffrey; Long, Joel; Quevedo, Hernan J.; Rambo, Patrick K.; Riley, Nathan R.; Schwarz, Jens; Shores, Jonathon; Stahoviak, John; Ampleford, David; Porter, John L.; Ditmire, Todd; Looker, Quinn M.; Struve, Kenneth

We report on experimental measurements of how an externally imposed magnetic field affects plasma heating by kJ-class, nanosecond laser pulses. The experiments reported here took place in gas cells analogous to magnetized liner inertial fusion targets. We observed significant changes in laser propagation and energy deposition scale lengths when a 12T external magnetic field was imposed in the gas cell. We find evidence that the axial magnetic field reduces radial electron thermal transport, narrows the width of the heated plasma, and increases the axial plasma length. Reduced thermal conductivity increases radial thermal gradients. This enhances radial hydrodynamic expansion and subsequent thermal self-focusing. Our experiments and supporting 3D simulations in helium demonstrate that magnetization leads to higher thermal gradients, higher peak temperatures, more rapid blast wave development, and beam focusing with an applied field of 12T.

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TYPE Journal Article YEAR 2021
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Results 10901–10950 of 101,000
Results 10901–10950 of 101,000
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