Sandia National Laboratories, New Mexico
solid state Materials at high pressures and temperatures
Sergio Pineda Flores, University of California, Berkeley
Practicum Year: 2019
Practicum Supervisor: Luke Shulenburger, staff scientiest, High Energy Density Physics Theory department, Sandia National Laboratories, New Mexico
My project can be divided into two efforts. The first is the study of FeO's strain curve using various Quantum Monte Carlo wave functions and methods to unambiguously determine the shape of the strain curve. The second is the study of LiF's optical properties at extreme pressures/temperatures using DFT/MD methods and kubo-greenwood formula.
Shifting the homogeneous phase transition of water to ice VII by manipulating the isentropic loading path
Erin Nissen, University of Illinois at Urbana-Champaign
Practicum Year: 2018
Practicum Supervisor: Daniel Dolan, Dr. , Dynamic Material Properties (1646), Sandia National Laboratories, New Mexico
During this practicum we utilized the versatility of Sandia National Lab’s Thor-64 machine, where a tunable current pulse (80 kV) generates a magnetic drive to isentropically compress a sample of interest. In our case, we were interested in the homogenous phase transition of liquid water to solid ice VII. Previous studies have focused on peak pressure and window material as major factors for the onset of freezing. We took a different approach and looked at the effects of initial temperature and ramp rate. We found that increasing the initial temperature changes the isentropic loading path and results in a much higher phase transition pressure. We also found that decreasing the rap rate, or decreasing the rate of compression, decreased the transition pressure; however, it effected the initial room temperature isentropic loading paths less than the increased initial temperature paths.
Ab-initio MD calculations of material properties at high temperature and pressure
Gil Shohet, Stanford University
Practicum Year: 2018
Practicum Supervisor: Michael Desjarlais, Senior Scientist, Pulsed Power Sciences Center, Sandia National Laboratories, New Mexico
For the practicum project I learned to use the Vasp DFT code for ab initio molecular dynamics. Using this tool, I studied hydrogen under high pressure with two different potentials, looking for the critical point in the liquid-liquid insulator-metal transition and doing conductivity calculations. I also studied the forsterite vapor dome to compute the critical point for this material.
Optical Diagnostics on the Pecos Test Chamber
Daniel Woodbury, University of Maryland, College Park
Practicum Year: 2018
Practicum Supervisor: Adam Harvey-Thompson, Senior technical staff, 01600, Pulsed Power Sciences, Sandia National Laboratories, New Mexico
The Pecos test chamber is used to study laser preheat on MagLIF targets for Z, but in an offline environment that is more accessible in terms of shot rate and diagnostics. This allows much more rapid development of new target designs and preheating platforms that can be benchmarked for performance before fielding on Z, which has a much slower shot rate and higher risk.
Influence of Chemistry in HMX-based PBX Initiation
Christopher Miller, Georgia Institute of Technology
Practicum Year: 2018
Practicum Supervisor: Cole Yarrington, Dr., 1000, Sandia National Laboratories, New Mexico
This project involves modeling HMX-based polymer bonded explosive misrostructures and how they evolve under shock loading. These 2D simulations were performed using Sandia's Eulerian hydrocode - CTH. The effects of chemistry were modeled and the run-to-detonation distance was calculated as a function of shock pressure.
Coupling kinetic to continuum methods for plasma physics in 1-D
Richard Vega, Texas A&M University
Practicum Year: 2018
Practicum Supervisor: Thomas Gardiner, R&D S&E, Physics, 1641, Sandia National Laboratories, New Mexico
The project involved writing 3 codes: a magneto-hydrodynamics (MHD) code, a two-fluid (TF) plasma code, and a particle in cell (PIC) code. With the three working codes, the goal was then to couple PIC to TF in the regime where their traditional applications overlap.
In situ experimental development at the Sandia Ion Beam Lab
Cody Dennett, Massachusetts Institute of Technology
Practicum Year: 2017
Practicum Supervisor: Khalid Hattar, Staff Scientist, Radiation Solid Interactions - Sandia Ion Beam Lab, Sandia National Laboratories, New Mexico
Designed and built and in situ, laser-based materials diagnostic for the 6 MV tandem accelerator at the Sandia Ion Beam Lab. Experiment will be used to track the thermal and mechanical properties of materials subject to ion beam irradiation in near real time.
Developing Environmentally Stable Oxides on Metals using Pulsed Laser Irradiation
Samantha Lawrence, Purdue University
Practicum Year: 2014
Practicum Supervisor: David P. Adams, Distinguished Member of the Technical Staff, Org. 1832, Coatings and Surface Engineering, Sandia National Laboratories, New Mexico
Surface laser-irradiation of oxidizing metals such as stainless steel induces a high-temperature chemical reaction between the metal and ambient atmosphere, resulting in the growth of a film composed of elements from the substrate in combination with environmental gasses. Such films are highly colored and may find use as unique authenticity markings in welded components. The practicum research focused on critical experimental studies to develop materials processing methods to ensure sealed components are robust in harsh corrosive and embrittling environments. As it is likely that laser-induced Cr-depletion from stainless steel substrates is the primary cause of corrosion for the oxidized SS 304L, a set of conditions to will control the environmental resistance of alloys subjected to laser processing was predicted. A set of experiments assessed the effectiveness of pre- and post-treatment of SS 304L for reducing Cr dissolution.
Sunshine to Petrol (S2P)
Elizabeth Miller, Northwestern University
Practicum Year: 2012
Practicum Supervisor: Andrea Ambrosini, Senior Member of Technical Staff, Materials, Devices & Energy Tech, Sandia National Laboratories, New Mexico
For the twelve weeks of my practicum, I was part of Sandia National Laboratories’ Sunshine to Petrol (S2P) project. As the United States seeks to become energy-independent, novel methods for sourcing fuels are required. It is not feasible to have an immediate shift to all renewable energy sources, especially in the area of transportation fuels, and thus, easily implementable, renewable energy sources with shorter time scales are needed. The S2P Program aims to fulfill this need by researching thermochemical fuel production fueled by concentrated solar power. The overarching goal of this project is to find materials that can split carbon dioxide and water. Products from these reactions (carbon monoxide and hydrogen, respectively) can then be used as precursors for the manufacture of hydrocarbon fuels. Current materials which have been successful for this purpose such as ceria have been well-studied but are limited in efficiency; thus the search for better performing, thermodynamically and kinetically favorable redox systems must be expanded.
Ab initio simulations of warm, dense deuterium for x-ray scattering
Paul Davis, University of California, Berkeley
Practicum Year: 2010
Practicum Supervisor: Michael Desjarlais, Manager, Diagnostics and Target Physics, Sandia National Laboratories, New Mexico
This project uses Sandia computer systems and simulation tools to study the properties of deuterium under extreme conditions. In particular, MD-DFT simulations were performed and analyzed to compare to recent x-ray scattering experiments that were performed at LLNL.
Streaked Visible Spectroscopic Measurements on the Z Machine
Matthew Gomez, University of Michigan
Practicum Year: 2009
Practicum Supervisor: Mike Cuneo, Manager, , Sandia National Laboratories, New Mexico
A fiber coupled streaked spectroscopic system was set up to be fielded on the Z machine at Sandia National Labs. This diagnostic was used to observe light emission by z-pinch wires during the initial ablation stage. It was also used to observe light emission from a photo-ionized neon gas cell. Future experiments that will utilize this diagnostic include observation of the plasma formed in a post-hole convolute and hydrogen/helium gas cell emission/absorption with applications to white dwarf stars.
Initial Wetting Tests for the Liquid Lithium Divertor (LLD)
Laura Berzak Hopkins, Princeton University
Practicum Year: 2007
Practicum Supervisor: Richard Nygren, Manager, Fusion Technology Department, Sandia National Laboratories, New Mexico
The National Spherical Torus eXperiment (NSTX) at the Princeton Plasma Physics Laboratory (PPPL) intends to install a novel liquid lithium divertor (LLD) prior to the next run campaign. Before the final divertor can be built, design and materials testing must be completed in order to ascertain the parameters for an optimal device. While design work is underway, Sandia is involved in materials testing. The initial wetting tests are an examination of a unique molybdenum foam and the behavior of lithium in its presence. Thermocouple and IR data are gathered from both bench-top and vacuum heating tests of the foam itself. In addition, lithium foil is melted on to the foam and a variety of both qualitative and quantitative data regarding the manner in which the lithium wets the foam is collected.