scholarly journals Shock-Driven Decomposition of Polymers and Polymeric Foams

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 493 ◽  
Author(s):  
Dana Dattelbaum ◽  
Joshua Coe
Keyword(s):  
Shock Loading ◽  
Equations Of State ◽  
National Laboratory ◽  
Decomposition Products ◽  
Los Alamos National Laboratory ◽  
Carbon Soot ◽  
High Level ◽  
Future Work ◽  
Sufficient Strength ◽  
Reaction Wave

Polymers and foams are pervasive in everyday life, as well as in specialized contexts such as space exploration, industry, and defense. They are frequently subject to shock loading in the latter cases, and will chemically decompose to small molecule gases and carbon (soot) under loads of sufficient strength. We review a body of work—most of it performed at Los Alamos National Laboratory—on polymers and foams under extreme conditions. To provide some context, we begin with a brief review of basic concepts in shockwave physics, including features particular to transitions (chemical reaction or phase transition) entailing an abrupt reduction in volume. We then discuss chemical formulations and synthesis, as well as experimental platforms used to interrogate polymers under shock loading. A high-level summary of equations of state for polymers and their decomposition products is provided, and their application illustrated. We then present results including temperatures and product compositions, thresholds for reaction, wave profiles, and some peculiarities of traditional modeling approaches. We close with some thoughts regarding future work.

scholarly journals Verification Studies for the Noh Problem Using Nonideal Equations of State and Finite Strength Shocks

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Sarah C. Burnett ◽  
Kevin G. Honnell ◽  
Scott D. Ramsey ◽  
Robert L. Singleton
Keyword(s):  
Equations Of State ◽  
National Laboratory ◽  
Jump Conditions ◽  
Self Similarity ◽  
Planar Case ◽  
Los Alamos National Laboratory ◽  
Flow Equations ◽  
Arbitrary Strength ◽  
Verification Test ◽  
Gamma Law

The Noh verification test problem is extended beyond the commonly studied ideal gamma-law gas to more realistic equations of state (EOSs) including the stiff gas, the Noble-Abel gas, and the Carnahan–Starling EOS for hard-sphere fluids. Self-similarity methods are used to solve the Euler compressible flow equations, which, in combination with the Rankine–Hugoniot jump conditions, provide a tractable general solution. This solution can be applied to fluids with EOSs that meet criterion such as it being a convex function and having a corresponding bulk modulus. For the planar case, the solution can be applied to shocks of arbitrary strength, but for the cylindrical and spherical geometries, it is required that the analysis be restricted to strong shocks. The exact solutions are used to perform a variety of quantitative code verification studies of the Los Alamos National Laboratory Lagrangian hydrocode free Lagrangian (FLAG).

In search of an optimum plutonium density measurement fluid

2009 ◽  
Vol 97 (4-5) ◽  
Author(s):  
K. M. Dziewinska ◽  
A. M. Peters ◽  
J. A. La Verne ◽  
P. Martinez ◽  
J. J Dziewinski ◽  
...  
Keyword(s):  
National Laboratory ◽  
Density Measurement ◽  
Chemical Properties ◽  
Decomposition Products ◽  
Los Alamos National Laboratory ◽  
Corrosion Rates ◽  
Physical And Chemical ◽  
Near Future ◽  
Plutonium Metal

AbstractDensity measurements of plutonium metal and its alloys are performed at Los Alamos National Laboratory (LANL) using a technique based on the Archimedes principle. The goal is to find and characterize a fluid for density determination of large objects made of plutonium to replace the currently used monobromobenzene. Physical and chemical properties must be considered while selecting the fluid. Chemical properties of the fluid must ensure low corrosion rates and good resistance to radiological decomposition. The study was carried on to evaluate the corrosion rates of Pu metal cause by FC-43 and the FC-43 decomposition products of radiolysis. The results of these studies proved favourable for this application. The evaluation of the surface reactions between FC-43 and Pu metal will be conducted in the near future.

Configuration Management for Modular Flexible Small Automation Systems: A Case Study

2000 ◽  
Author(s):  
Cameron J. Turner ◽  
Jacy M. Legault ◽  
Dan J. Cox
Keyword(s):  
Decision Making ◽  
National Laboratory ◽  
Configuration Management ◽  
Management Systems ◽  
Alamos National Laboratory ◽  
Los Alamos National Laboratory ◽  
Automation Systems ◽  
High Level ◽  
Integrated Extraction

Abstract Configuration management provides designers of automation systems with a framework to develop effective automation systems despite their inherent complexity. By managing the complexity of the system, and assisting in low-level decision-making, configuration management systems enable human designers, operators and system technicians to focus on high-level decision-making where their knowledge and experience are the most valuable. The development of flexible, modular small automation systems for the Advanced Recovery and Integrated Extraction System (ARIES) Pilot Line at Los Alamos National Laboratory, can serve as a case study for the development of a configuration management methodology. Furthermore, this case study can be used to identify potential design tools that can assist in the development of automation systems. An examination of a specific case, that of the Hot-side Electrodecontamination Chamber of the ARIES Pilot Line has been used to identify necessary research developments and demonstrate the utility of the configuration management process.

A Knowledge-Based Approach for the Automated Design of Robotic/Human Manufacturing Workcells in Hazardous Environments

2013 ◽  
Author(s):  
Joshua M. Williams ◽  
Mitch W. Pryor
Keyword(s):  
Manufacturing Systems ◽  
National Laboratory ◽  
Computational Design ◽  
Los Alamos National Laboratory ◽  
Knowledge Based ◽  
Design Engineers ◽  
Hazardous Environments ◽  
Interdisciplinary Knowledge ◽  
High Level ◽  
System Designs

The design of manufacturing systems in hazardous environments is complex, requiring interdisciplinary knowledge to determine which components and operators (human or robotic) are feasible. When conceptualizing designs, some options may be overlooked or unknowingly infeasible due to the design engineers’ lack of knowledge in a particular field or ineffective communication of requirements between disciplines. Computational design tools can help alleviate many of the problems encountered in this design task. We create a knowledge-based system (KBS) utilizing CLIPS to automate the synthesis of conceptual manufacturing system designs in radioactive environments. The KBS takes a high-level functional description of a process and uses FBS modeling to generate multiple designs with generic components retrieved from a database and low-level manufacturing task sequences. Using this approach, many options are explored and operator task compatibility is directly addressed. The KBS is applied to the design of glovebox processing systems at Los Alamos National Laboratory (LANL).

Potential Hazard of Ferrocyanide Salts in High-Level Waste Tanks Within the Hanford Tank Farm

1991 ◽  
Vol 257 ◽  
Author(s):  
S. F. Agnew ◽  
S. W. Eisenhawer ◽  
R. F. Davidson ◽  
L. H. Sullivan
Keyword(s):  
National Laboratory ◽  
Computer Code ◽  
High Level Waste ◽  
Potential Hazard ◽  
Los Alamos National Laboratory ◽  
The Past ◽  
Tank Farm ◽  
Waste Tanks ◽  
High Level ◽  
Nickel Ferrocyanide

ABSTRACTOver the past few years, there has been an increased awareness of the potential hazard of energetic chemical reactions in high-level radioactive waste tanks at the Hanford tank farm. In particular, a mixture of Na2NiFe(CN)6 with NaNO3 and NaNO2 in several high-level waste tanks has caused concern. The problem of the FeCN tanks is fundamentally one of a potentially unstable mixture of fuel (the CN- moiety) and oxidizer (NO3- or NO2-).At Los Alamos National Laboratory, we have performed an extensive reanalysis of the safety problems associated with the presence of Na2NiFe(CN)6 mixed with NaNO3/NO2 for a particular tank (104-BY) that contains by far the largest amount of the nickel ferrocyanide salt (∼2E5 mol). Our approach is to use conservative assumptions to bound both the energy density for a potential runaway reaction and the mass that could participate if we assume ignition as the result of bounding radionuclide concentrations. The subsequent progress of the accident is analyzed using an advanced hydrodynamics computer code called MESA to evaluate the loads on the structure and the generation of aerosols. The subsequent doses are shown to be low both on and off the site. The conservatism in the analysis is quite large, and the expected results using more realistic assumptions are discussed.

Void Nucleation and Growth at Grain Boundaries in Copper Bicrystals With Surface Perturbations

2016 ◽  
Author(s):  
Elizabeth V. Fortin ◽  
Saul Opie ◽  
Andrew D. Brown ◽  
Jenna M. Lynch ◽  
Eric Loomis ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Strain Localization ◽  
Shock Loading ◽  
Void Nucleation ◽  
National Laboratory ◽  
Los Alamos National Laboratory ◽  
Release Wave ◽  
Grain Bulks ◽  
Deformation Patterns ◽  
Photolithography Process

Material failure on the microstructural level is important in determining macroscale behavior. When a material is subjected to dynamic (shock) loading conditions, damage and deformation patterns due to spall failure can provide a basis for connecting micro- to macroscale behavior. By analyzing deformation patterns at and around interfaces and boundaries that are representative of those found in engineering materials at high strain rates, we can develop stronger structures that can withstand impact collisions and rapid crack propagation. The addition of surface perturbations to one side of the samples provides insight on how strain localization occurs during the shock loading process and how the rippled release wave interacts with the boundary. Copper bicrystal samples were grown from two single crystal seeds using the vertical Bridgeman technique. A photolithography process was developed to create periodic surface perturbations on one side of the samples. The square wave ripples had a 150 μm wavelength and 5 μm amplitude. The bicrystals were shocked using laser ablation on the perturbation side at the Trident laser at Los Alamos National Laboratory and monitored using a VISAR (velocity interferometer systems for any reflector) and TIDI (transient imaging displacement interferometry) system. Shock pressures used were around 8–10 GPa. Targets measured 5 mm in diameter and 100 microns thick. The orientations of the grains were [001] and [111] along the shock direction with a 50° misorientation angle for the boundary, which was aligned parallel to the shock direction. Samples were soft recovered and cross-sectioned to perform quantitative characterization of damage using electron backscattering diffraction (EBSD) and Scanning Electron Microscopy (SEM) to gather information on the characteristics of the grain boundary and its surroundings, with emphasis on how the rippled surfaces and material anisotropy affected strain localization and spallation, initial results show that damage indeed localized at the grain boundary and that surface perturbations led to heterogeneity of spall damage distribution in the grain bulks.

scholarly journals Graphs in Libraries: A Primer

2011 ◽  
Vol 30 (4) ◽  
pp. 157 ◽  
Author(s):  
James E. Powell ◽  
Daniel A. Alcazar ◽  
Matthew Hopkins ◽  
Tamara M. McMahon ◽  
Amber Wu ◽  
...  
Keyword(s):  
Graph Theory ◽  
Digital Libraries ◽  
National Laboratory ◽  
Laboratory Research ◽  
Los Alamos National Laboratory ◽  
Practical Applications ◽  
Retrieval Systems ◽  
Information Retrieval Systems ◽  
Potential Applications ◽  
High Level

Whenever librarians use Semantic Web services and standards for representing data, they also generate graphs, whether they intend to or not. Graphs are a new data model for libraries and librarians, and they present new opportunities for library services. In this paper we introduce graph theory and explore its real and potential applications in the context of digital libraries. Part 1 describes basic concepts in graph theory and how graph theory has been applied by information retrieval systems such as Google. Part 2 discusses practical applications of graph theory in digital library environments. Some of the applications have been prototyped at the Los Alamos National Laboratory Research Library, others have been described in peer-reviewed journals, and still others are speculative in nature. The paper is intended to serve as a high-level tutorial to graphs in libraries.

Automated mineral analysis in TASK8

1990 ◽  
Vol 48 (2) ◽  
pp. 212-213
Author(s):  
William F. Chambers ◽  
Arthur A. Chodos ◽  
Roland C. Hagan
Keyword(s):  
National Laboratory ◽  
Control Program ◽  
Mineral Analysis ◽  
Alamos National Laboratory ◽  
Mineral Phase ◽  
Los Alamos National Laboratory ◽  
California Institute Of Technology ◽  
Mineral Phases ◽  
Letter Code ◽  
Institute Of Technology

TASK8 was designed as an electron microprobe control program with maximum flexibility and versatility, lending itself to a wide variety of applications. While using TASKS in the microprobe laboratory of the Los Alamos National Laboratory, we decided to incorporate the capability of using subroutines which perform specific end-member calculations for nearly any type of mineral phase that might be analyzed in the laboratory. This procedure minimizes the need for post-processing of the data to perform such calculations as element ratios or end-member or formula proportions. It also allows real time assessment of each data point.The use of unique “mineral codes” to specify the list of elements to be measured and the type of calculation to perform on the results was first used in the microprobe laboratory at the California Institute of Technology to optimize the analysis of mineral phases. This approach was used to create a series of subroutines in TASK8 which are called by a three letter code.

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