Exploring The Effect Of Sample Properties On Spark-Induced Breakdown Spectroscopy,
2015
Purdue University
Exploring The Effect Of Sample Properties On Spark-Induced Breakdown Spectroscopy, Michael J. Marino, Payson Dieffenbach, Liesl A. Krause, Prasoon Diwakar, Ahmed Hassanein
The Summer Undergraduate Research Fellowship (SURF) Symposium
Optical emission spectroscopy techniques such as laser-induced breakdown spectroscopy (LIBS) and spark-induced breakdown spectroscopy (SIBS) provide portable and robust methods for elemental detection in real-time. Laser-produced emissions are then used for quantitative and qualitative analysis of a sample material with applications in explosives detection. For both techniques, the main obstacles have always been signal intensity, accuracy, and sensitivity of detection. The main advantage of the SIBS method is more safe operation, while still maintaining the portability of the technique. In this study, detailed characterization of spark induced plasma, analyte emission intensity, plasma temperature, electron density, and plasma persistence has been …
Effect Of Carbon Impurity On Molybdenum Nanostructure Evolution Under Helium Ion Irradiation In Extreme Conditions,
2015
Purdue University
Effect Of Carbon Impurity On Molybdenum Nanostructure Evolution Under Helium Ion Irradiation In Extreme Conditions, Nikhil A. Bharadwaj, Jitendra Tripathi, Ahmed Hassanein, Sean Gonderman
The Summer Undergraduate Research Fellowship (SURF) Symposium
The performance of plasma facing components (PFC) is of great important for the realization of prototype nuclear fusion. Tungsten has been considered as the leading high-Z PFC material for these reactors and tokamaks due to its superior thermophysical properties, high melting point, low sputtering yield, and low tritium inventory. However, its surface deteriorates significantly under helium ion irradiation in extreme (fusion) conditions and forms nanoscopic fiber like structures (fuzz) Recent studies show that the formation of fuzz nanostructure on tungsten can be suppressed by the presence of plasma impurities such as carbon and beryllium. In the present study, the effects …
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization,
2015
Purdue University
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization, Abhijit Jassem, Michael Lauria, Russell Brayfield Ii, Kevin M. Keener, Allen L. Garner
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is a growing need for economical, effective, and safe methods of sterilizing fresh produce. The most common method is a chlorine wash, which is expensive and may introduce carcinogens. High voltage cold atmospheric pressure plasmas are a promising solution that has demonstrated a germicidal effect; however, the responsible chemical mechanisms and reaction pathways are not fully understood. To elucidate this chemistry, we used optical emission spectroscopy to measure the species produced in the plasma generated by a 60 Hz pulsed dielectric barrier discharge in a plastic box containing various fill gases (He, N2, CO2, dry …
Design And Fabrication Of Liquid Scintillator Counter,
2015
California State University - Long Beach
Design And Fabrication Of Liquid Scintillator Counter, Andrea Calderon Saucedo, John L. Orrell
STAR Program Research Presentations
Pacific Northwest National Laboratory (PNNL) is currently developing an ultra-low background liquid scintillator counter (ULB LSC) in the shallow underground laboratory. At a depth of 35-meters water-equivalent, the underground laboratory has a multi-layered shielding to keep out cosmic-ray induced background. The ULB LSC, which is located in a clean room facility, is a multi-layered design made up of various materials, including plastic scintillator veto panels, borated polyethylene, lead and copper. These layers help lower the contributions of the terrestrial background and intrinsic background, resulting from the impurities present in the materials, to the overall background count rate observed by the …
Impurity Diffusion As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics,
2015
United States Military Academy
Impurity Diffusion As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics, Edward T. Peskie, Howard L. Hall
International Journal of Nuclear Security
The ability to determine the age of seized nuclear material—that is, the time that has passed since it was formed— would provide crucial data to be used in its investigation. This paper reviews the methods and mathematical reasoning behind the use of diffusion theory, as previously applied to analysis of metals in ancient artifacts and other objects, to modern investigations in nuclear science. We here examine the time-dependent processes of diffusion, including grain boundary diffusion and discontinuous precipitation, and we assess the utility of examining the profiles of impurity and alloying element concentrations for use as a tool in pre-detonation …
Student Writing Competition,
2015
University of Tennessee, Knoxville
Student Writing Competition
International Journal of Nuclear Security
No abstract provided.
Cover,
2015
University of Tennessee, Knoxville
Masthead,
2015
University of Tennessee, Knoxville
From The Editor,
2015
University of Tennessee, Knoxville
The Nuclear Security Science And Policy Institute At Texas A&M University,
2015
Texas A&M University
The Nuclear Security Science And Policy Institute At Texas A&M University, Claudio A. Gariazzo, Kelley H. Ragusa, David R. Boyle, William S. Charlton, Sunil S. Chirayath, Craig M. Marianno, Paul Nelson Jr.
International Journal of Nuclear Security
The Nuclear Security Science and Policy Institute (NSSPI) is a multidisciplinary organization at Texas A&M University and was the first U.S. academic institution focused on technical graduate education, research, and service related to the safeguarding of nuclear materials and the reduction of nuclear threats. NSSPI employs science, engineering, and policy expertise to: (1) conduct research and development to help detect, prevent, and reverse nuclear and radiological proliferation and guard against nuclear terrorism; (2) educate the next generation of nuclear security and nuclear nonproliferation leaders; (3) analyze the interrelationships between policy and technology in the field of nuclear security; and (4) …
Addressing Imbalances In Us Nuclear Economic And Nonproliferation Policies,
2015
Institute for Nuclear Security
Addressing Imbalances In Us Nuclear Economic And Nonproliferation Policies, Matthew S. Duchene, Howard L. Hall
International Journal of Nuclear Security
Foreign civilian nuclear start-ups have an increasing number of international partners capable of supplying fuel cycle technologies. The desire to prevent the spread of dual-use enrichment and reprocessing technology by asking partner states to rely on international fuel markets is a major obstacle for US negotiating civilian nuclear trade agreements, leading to delays. US participation in emerging nuclear markets is being undercut by foreign competition, leading to decreasing economic competition and influence in international nonproliferation issues. It is therefore necessary for the US to reinvest and complete its domestic nuclear fuel cycle and modify its process for implementing civilian nuclear …
Radiation Damage As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics,
2015
United States Military Academy
Radiation Damage As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics, Edward T. Peskie, Howard L. Hall
International Journal of Nuclear Security
The better we can determine how long ago nuclear material was made, the sharper our tools for investigating seized nuclear materials. This paper examines the effects of radiation damage caused by the decay of uranium isotopes, and assesses how experts in nuclear forensics could use the analyses of these damaged regions to determine how much time has passed since metal samples were formed. It also draws parallels from fission track dating studies of mineral samples under geologic time, and proposes modifications to past publications on α-recoil track dating in order to determine the time since a metal sample was cast …
Coupling Nuclear Induced Phonon Propagation With Conversion Electron Mössbauer Spectroscopy,
2015
Air Force Institute of Technology
Coupling Nuclear Induced Phonon Propagation With Conversion Electron Mössbauer Spectroscopy, Michael J. Parker
Theses and Dissertations
Mössbauer spectroscopy is a very sensitive measurement technique (10-8 eV) which prompted motivation for the experiment described in this thesis. Namely, can a sensitive detection system be developed to detect nuclear recoils on the order of 10 to 100 of eVs? The hypothesis that this thesis tests is: Nuclear induced phonon bursts caused by Rutherford scattered alphas, decayed from 241Am, in a type-310 stainless steel material can couple with 7.3 keV conversion electron Mössbauer events at the other end of the material which will have a statistically significant effect on a Mössbauer spectrum. The phonon bursts produced by …
Well-Posedness And Convergence Of Cfd Two-Fluid Model For Bubbly Flows,
2015
Purdue University
Well-Posedness And Convergence Of Cfd Two-Fluid Model For Bubbly Flows, Avinash Vaidheeswaran
Open Access Dissertations
The current research is focused on developing a well-posed multidimensional CFD two-fluid model (TFM) for bubbly flows. Two-phase flows exhibit a wide range of local flow instabilities such as Kelvin-Helmholtz, Rayleigh-Taylor, plume and jet instabilities. They arise due to the density difference and/or the relative velocity between the two phases. A physically correct TFM is essential to model these instabilities. However, this is not the case with the TFMs in numerical codes, which can be shown to have complex eigenvalues due to incompleteness and hence are ill-posed as initial value problems. A common approach to regularize an incomplete TFM is …
Surface Geometry And Chemistry Of Hydrothermally Synthesized Single Crystal Thorium Dioxide,
2015
Air Force Institute of Technology
Surface Geometry And Chemistry Of Hydrothermally Synthesized Single Crystal Thorium Dioxide, Scott W. Key
Theses and Dissertations
The surface chemistry and geometry of hydrothermally grown, single crystal ThO2 was studied using X-ray Photoemission Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The crystal was studied before and after sputter etching with Ar+, heating up to 675 K, and dehydration with dry nitrogen. The hydrothermal growth technique incorporated Cs and F into the near surface bulk. Heating to 675 K drove off the F, but did not the Cs. Sputtering with Ar+ at 75° cleaned the crystal and created a more uniform surface geometry. The Th 4f peak resolution, as measured by XPS improved by …
The Effect Of Anisotropic Scatter On Atmospheric Neutron Transport,
2015
Air Force Institute of Technology
The Effect Of Anisotropic Scatter On Atmospheric Neutron Transport, Nicholas J. Mcintee
Theses and Dissertations
Anisotropy is present in the angular distributions of neutrons departing from a nuclear scattering event. This anisotropy cannot be defined in a closed-form solution, and it is dependent on the incident neutron energy, elastic or inelastic scatter, along with the inelastic level, and the species struck. The underlying question is, if anisotropic behavior is worth the computational cost to be included in certain simulations, and if so, what level of precision is effected by the inclusion of anisotropic scatter. A Watt spectrum of U235 fission neutrons was examined as it collided with species in a nitrogen-oxygen atmosphere. In a …
Balancing Domestic Nuclear Industry Viability With International Security: Imminent Changes To Nuclear Export Control Regulations,
2015
Brigham Young University Law School
Balancing Domestic Nuclear Industry Viability With International Security: Imminent Changes To Nuclear Export Control Regulations, H. Brendan Burke
Brigham Young University International Law & Management Review
No abstract provided.
Two-Dimensional Temperature Analysis Of Nuclear Fireballs Using Digitized Film,
2015
Air Force Institute of Technology
Two-Dimensional Temperature Analysis Of Nuclear Fireballs Using Digitized Film, Robert C. Slaughter, Tyler R. Peery, John W. Mcclory
Faculty Publications
Researchers at Lawrence Livermore National Laboratory have begun digitizing technical films spanning the atmospheric nuclear testing operations conducted by the United States from 1945 through 1962. Each atmospheric nuclear test was filmed by Edgerton, Germeshausen, and Grier, Inc., using between 20 to 40 cameras per test. These technical film test data represent a primary source for advancing the knowledge of nuclear weapon output as well as the understanding of nonnuclear high-temperature gases. This manuscript outlines the procedures followed in order to perform two-dimensional temperature calculations for early time nuclear fireballs using digitized film. The digitized optical densities of the film …
Young's Modulus Of [111] Germanium Nanowires,
2015
Virginia Commonwealth University
Young's Modulus Of [111] Germanium Nanowires, M. Maksud, J. Yoo, C. T. Harris, N. K. R. Palapati, A. Subramanian
Mechanical and Nuclear Engineering Publications
This paper reports a diameter-independent Young’s modulus of 91.9 ± 8.2 GPa for [111] Germaniumnanowires (Ge NWs). When the surface oxide layer is accounted for using a core-shell NW approximation, the YM of the Ge core approaches a near theoretical value of 147.6 ± 23.4 GPa. The ultimate strength of a NW device was measured at 10.9 GPa, which represents a very high experimental-to-theoretical strength ratio of ∼75%. With increasing interest in this material system as a high-capacity lithium-ion battery anode, the presented data provide inputs that are essential in predicting its lithiation-induced stress fields and fracture behavior.
Fsae Pedal Box: Controlling Stop And Go,
2015
Virginia Commonwealth University
Fsae Pedal Box: Controlling Stop And Go, Christopher Hathcock, Tyler Munden
Capstone Design Expo Posters
The VCU FSAE team has a need for foot controls for the brakes and throttle on their newest race car. The assembly must meet the rules set forth by the FSAE organization to compete, and must be as light and low as possible to conserve the acceleration and handling characteristics of the car. Furthermore, the project must be completed on a budget of $500 allotted to Senior Design teams. The FSAE team has been working on the current car since 2005 and has yet to produce a drivable race car. The Senior Design teams this year cover the major systems …
