Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
Articles 1 - 10 of 10
Full-Text Articles in Engineering
Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott
Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott
Theses and Dissertations
Carbon Fiber (CF) has different tensile strengths and transverse moduli depending on how they are fabricated. Some CF is export controlled as it can be used for weapons, spacecraft, or gas centrifuges for enriching nuclear fuel. This research project explored a new way to prepare micron sized single CF threads to measure their transverse modulus and compare the moduli of non-export controlled CF to that of an export controlled CF. Five total polyacrylonitrile (PAN) fibers were used in this project, one of which was an export controlled fiber.
Characterization And Analysis Of Bomarc Accident Debris, Aaron J. Heffelfinger
Characterization And Analysis Of Bomarc Accident Debris, Aaron J. Heffelfinger
Theses and Dissertations
Accidents involving nuclear weapons, such as the Boeing Michigan Aeronautical Research Center (BOMARC) accident in 1960, always pose a significant risk of allowing particles composed of nuclear materials to enter the environment. These particles often differ in characteristics and can be of greatly varying sizes. Gamma ray analysis was conducted on the soil sample and radioisotopes within the sample were identified. Two non-destructive methods for locating actinide bearing particles within the sample were testing, resulting in 70 actinide bearing particles ranging from 1-34 microns being identified. These 70 particles underwent both morphological and elemental characterization, indicating uranium and other elements.
Application Of Artificial Neural Networks To Elemental Assay Data For Nuclear Forensics Analysis, Jason G. Seik
Application Of Artificial Neural Networks To Elemental Assay Data For Nuclear Forensics Analysis, Jason G. Seik
Theses and Dissertations
There is a need to quickly and accurately determine the likely physical origins of a collected sample for nuclear treaty verification purposes. The objective of this research is to prove there is a means to relate different samples (Q-values) to one another using a 'same versus not-same' artificial neural network called a Siamese network. This would provide the capability of comparing an unknown sample to a database of samples with known physical origins. Using moment transformations on current data has shown to increase the prediction capabilities of a Siamese network, and using a triplet loss function in connection with the …
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter
Faculty Publications
A 3-D Quarter-Core CANDU-6 is modeled using Serpent 2 for nuclear treaty monitoring. The spatial variation of flux spectra and isotopic concentrations is analyzed to determine the potential isotopic distribution of key radionuclides from standard reactor operations relevant to non-proliferation. The initial results of the model show a 46% difference in overall flux magnitude throughout the core as well as a 2-30% difference in discrete energy flux. The coupled production rate (magnitude) and spectral differences can contribute to significant spatial variations in isotope ratios throughout the core. Initial results indicate 239 Pu/ 240 Pu ratios vary by as much as …
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu-6 Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu-6 Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt
Theses and Dissertations
The Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization developed the International Monitoring System for monitoring for nuclear explosive testing and compliance with nuclear treaties. Many of the International Monitoring System stations are capable of detecting radionuclides that can be used to determine their origin and creation environment. However, there is not a single unique signature associated with each creation environment. Nuclear reactors, for example, can have a wide range of isotopic concentrations caused by spatial variations in neutron flux intensity and energy. As a single sample only provides a single isotopic measurement, this can make disambiguation difficult …
A Machine Learning Approach To Characterizing Particle Morphology In Nuclear Forensics, Daniel A. Gum
A Machine Learning Approach To Characterizing Particle Morphology In Nuclear Forensics, Daniel A. Gum
Theses and Dissertations
A machine learning approach is taken to characterizing a group of synthetic uranium bearing particles. SEM images of these lab-created particles were converted into a binary representation that captured morphological features in accordance with a guide established by Los Alamos National Laboratory. Each particle in the dataset contains an association with chemical creation conditions: processing method, precipitation temperature and pH, calcination temperature are most closely tied to particle morphology. Additionally, trained classifiers are able to relate final products between particles, implying that morphological features are shared between particles with similar composition.
Analysis Of The Correlation Between Re Filament Surface Features And Tims Performance, Christopher J. Mihal
Analysis Of The Correlation Between Re Filament Surface Features And Tims Performance, Christopher J. Mihal
Theses and Dissertations
Thermal Ionization Mass Spectrometry (TIMS) is an invaluable tool in nuclear forensics as it enables isotopic assays of actinides to be measured, permitting analysis to include special nuclear material isotopic assays, nuclear reactor monitoring, and treaty verification. In one method of measurement for the TIMS system, samples are deposited in solution form on high-purity rhenium filaments. The filaments are heated to evaporate the solvent, and then further heated to cause sample ionization, permitting the sample to be transmitted through a magnetic field which separates ions based on mass to charge ratio into detectors for counting. Heavier ions will be deflected …
Quantitative Analysis Of Cerium-Gallium Alloys Using A Hand-Held Laser Induced Breakdown Spectroscopy Device, Ashwin P. Rao, Matthew Cook, Howard L. Hall, Michael B. Shattan
Quantitative Analysis Of Cerium-Gallium Alloys Using A Hand-Held Laser Induced Breakdown Spectroscopy Device, Ashwin P. Rao, Matthew Cook, Howard L. Hall, Michael B. Shattan
Faculty Publications
A hand-held laser-induced breakdown spectroscopy device was used to acquire spectral emission data from laser-induced plasmas created on the surface of cerium-gallium alloy samples with Ga concentrations ranging from 0–3 weight percent. Ionic and neutral emission lines of the two constituent elements were then extracted and used to generate calibration curves relating the emission line intensity ratios to the gallium concentration of the alloy. The Ga I 287.4-nm emission line was determined to be superior for the purposes of Ga detection and concentration determination. A limit of detection below 0.25%was achieved using a multivariate regression model of the Ga I …
Nuclear Forensics Applications Of Principal Component Analysis On Micro X-Ray Fluorescence Images, Sarah T. Castro
Nuclear Forensics Applications Of Principal Component Analysis On Micro X-Ray Fluorescence Images, Sarah T. Castro
Theses and Dissertations
A method is developed for rapid detection and analysis of actinides and correlated materials in nuclear fallout debris using principal component analysis on quantified micro x-ray fluorescence intensity values. This method is then applied to address goals of nuclear forensics. The first implementation is a collaborative effort with the National Institute of Standards and Technology and the Federal Bureau of Investigation Laboratory to produce a standard reference material that is a surrogate for glassy nuclear fallout debris in a modern urban environment. This reference material will enable researchers in the development and validation of nuclear forensics methods. A method for …
Differential (P, P′) And (P, D) Cross Sections Of 89Y And 92Zr, Molly A. Wakeling
Differential (P, P′) And (P, D) Cross Sections Of 89Y And 92Zr, Molly A. Wakeling
Theses and Dissertations
Differential cross sections for the (p, p′) and (p, d) reactions on 89Y and 92Zr were measured using a 28.25-MeV proton beam at the 88-inch cyclotron at Lawrence Berkeley National Laboratory. Angular distributions were obtained for the ground state and several excited states of each isotope using silicon detector telescopes over angles 10° to 140° in the reaction plane. These data were obtained by fitting a Gaussian function to each peak in the energy spectra and integrating the number of counts under each peak. These cross sections will be included in nuclear structure models …