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Articles 1201 - 1230 of 2568
Full-Text Articles in Physical Sciences and Mathematics
Astronomical Spectroscopy At The Cal Poly Observatory, Christopher James Almich
Astronomical Spectroscopy At The Cal Poly Observatory, Christopher James Almich
Physics
Embarking on the first ever astronomical spectroscopy project at the Cal Poly Observatory, I have tested the capabilities of our equipment. Our spectrograph, in conjunction with a telescope and CCD camera, is capable of making fairly precise measurements of absorption and emission lines with sub-nanometer precision. In my research I obtained a spectrum of Jupiter and was able to confidently identify a number of Fraunhofer solar absorption lines.
Adhesion And Durability Of Coatings On Polypropylene Exterior Sidings, Logan Riekio Stark
Adhesion And Durability Of Coatings On Polypropylene Exterior Sidings, Logan Riekio Stark
Master's Theses
Plastics have become a universal material for use in a myriad of commercial and consumer products. One such product, exterior siding, is the focus of this project. Although siding products were originally made from wood, vinyl siding, which offered superior performance, was introduced in the 1950’s. More recently, polypropylene (PP) siding has been introduced; PP provides a stronger product, which allows for deeper patterns and better edge detailing. PP siding, compared to traditional wood siding, doesn’t warp, crack, or degrade as easily with extended exposure to the elements, and is cheaper to maintain. However, even plastic siding must be coated. …
Hubble Space Telescope Imaging Of Post-Starburst Quasars, S. L. Cales, M. S. Brotherton, Zhaohui Shang, Vardha N. Bennert, G. Canalizo, R. Stoll, R. Ganguly, D. Vanden Berk, C. Paul, A. Diamond-Stanic
Hubble Space Telescope Imaging Of Post-Starburst Quasars, S. L. Cales, M. S. Brotherton, Zhaohui Shang, Vardha N. Bennert, G. Canalizo, R. Stoll, R. Ganguly, D. Vanden Berk, C. Paul, A. Diamond-Stanic
Physics
We present images of 29 post-starburst quasars (PSQs) from a Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Wide Field Channel Snapshot program. These broadlined active galactic nuclei (AGNs) possess the spectral signatures of massive (M burst ~ 1010 M ☉), moderate-aged stellar populations (hundreds of Myr). Thus, their composite nature provides insight into the AGN-starburst connection. We measure quasar-to-host galaxy light contributions via semi-automated two-dimensional light profile fits of point-spread-function-subtracted images. We examine the host morphologies and model the separate bulge and disk components. The HST/ACS-F606W images reveal an equal number …
Calibration Systems And Methods For Infrared Cameras, Russell Granneman, Nuwan Nagahawatte, Richard M. Goeden, Ted Takagi, Robert Ernst, Gary B. Hughes, Joseph Kostrzewa, John Graff, George Speake, Michael Kent, Neela Nalam, Stephen Lyon, Barbara Sharp, Pierre Boulanger, Neil Cutcliffe, Tim Martin, Ted Hoelter
Calibration Systems And Methods For Infrared Cameras, Russell Granneman, Nuwan Nagahawatte, Richard M. Goeden, Ted Takagi, Robert Ernst, Gary B. Hughes, Joseph Kostrzewa, John Graff, George Speake, Michael Kent, Neela Nalam, Stephen Lyon, Barbara Sharp, Pierre Boulanger, Neil Cutcliffe, Tim Martin, Ted Hoelter
Statistics
Systems and methods directed to calibration techniques for infrared cameras are disclosed. For example, a method of obtaining calibration information for an infrared device includes providing a calibration target adapted to provide a low-emissivity scene; performing a calibration operation on the infrared device to obtain the calibration information; and storing the calibration information.
Wavelength Dependence Of Transverse Mode Coupling With/Without E-Block Of Gan Laser Cavity, Krishneel Lal
Wavelength Dependence Of Transverse Mode Coupling With/Without E-Block Of Gan Laser Cavity, Krishneel Lal
Electrical Engineering
No abstract provided.
Similarity Scaling Of Turbulence Spectra And Cospectra In A Shallow Tidal Flow, Ryan K. Walter, Nicholas J. Nidzieko, Stephen G. Monismith
Similarity Scaling Of Turbulence Spectra And Cospectra In A Shallow Tidal Flow, Ryan K. Walter, Nicholas J. Nidzieko, Stephen G. Monismith
Physics
Measured turbulence power spectra, cospectra, and ogive curves from a shallow tidal flow were scaled using Monin‐Obukhov similarity theory to test the applicability to a generic tidal flow of universal curves found from a uniform, neutrally stable atmospheric boundary layer (ABL). While curves from individual 10 min data bursts deviate significantly from similarity theory, averages over large numbers of sufficiently energetic bursts follow the general shape. However, there are several differences: (1) Variance in the measured curves was shifted toward higher frequencies, (2) at low frequencies, velocity spectra were significantly more energetic than theory while cospectra were weaker, and (3) …
Road Runoff And Sediment Sampling For Determining Road Sediment Yield At The Watershed Scale, Christopher G. Surfleet, Arne E. Skaugset Iii, Matthew W. Meadows
Road Runoff And Sediment Sampling For Determining Road Sediment Yield At The Watershed Scale, Christopher G. Surfleet, Arne E. Skaugset Iii, Matthew W. Meadows
Natural Resources Management and Environmental Sciences
In this study, we demonstrate that watershed-scale estimates of road sediment production are improved if field measurements of road runoff and sediment production are used in the analysis. We used several techniques to spatially extrapolate measurements of road runoff and sampled sediment: comprehensive road runoff measurements, runoff estimates derived from the Distributed Hydrology Soil Vegetation Model (DHSVM), and adjustment of the road erosion models WARSEM and SEDMODL2.The sediment yield for the Oak Creek, Oregon, road network based on measured road runoff and sediment was 6.5 tons/year. When DHSVM was used to simulate road runoff, the estimated sediment from roads was …
Post-Fire Near-Surface Runoff From Small-Scale Rainfall Simulations, Santa Cruz Mountains, Michael Founds
Post-Fire Near-Surface Runoff From Small-Scale Rainfall Simulations, Santa Cruz Mountains, Michael Founds
Natural Resources Management and Environmental Sciences
The influence of environmental variables on the runoff response to a fire is poorly understood. Small-scale rainfall simulation was used to study the factors impacting near-surface runoff following the Lockheed Fire, which occurred on August 12, 2009. A variable speed rainfall simulator was used to rain on 15 different test plots at an average rate of 50mmh-1. Variables of burn severity, time following the fire, soil parent material, vegetation type, and presence of a duff layer were all analyzed using the ratio of runoff to rainfall. The difference in-between burned sites and similar control sites were 19±6%. Only …
Detection Of Pulsed Gamma Rays Above 100 Gev From The Crab Pulsar, E. Aliu, T. Arlen, T. Aune, M. Beilicke, W. Benbow, A. Bouvier, S. M. Bradbury, J. H. Buckley, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, J. L. Christiansen, L. Ciupik, E. Collins-Hughes, M. P. Connolly, W. Cui, R. Dickherber, C. Duke, M. Errando, A. Falcone, J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, K. Gibbs, G. H. Gillanders, S. Godambe, S. Griffin, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, H. Huan, G. Hughes, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, H. Krawczynski, F. Krennrich, M. J. Lang, M. Lyutikov, A. S. Madhavan, G. Maier, P. Majumdar, S. Mcarthur, A. Mccann, M. Mccutcheon, P. Moriarty, R. Mukherjee, P. Nuñez, R. A. Ong, M. Orr, A. N. Otte, N. Park, J. S. Perkins, P. T. Reynolds, E. Roache, J. Rose, J. Ruppel, D. B. Saxon, M. Schroedter, G. H. Sembroski, G. D. Şentürk, A. W. Smith, D. Staszak, G. Tešić, M. Theiling, S. Thibadeau, K. Tsurusaki, J. Tyler, A. Varlotta, V. V. Vassiliev, S. Vincent, M. Vivier, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, B. Zitzer
Detection Of Pulsed Gamma Rays Above 100 Gev From The Crab Pulsar, E. Aliu, T. Arlen, T. Aune, M. Beilicke, W. Benbow, A. Bouvier, S. M. Bradbury, J. H. Buckley, V. Bugaev, K. Byrum, A. Cannon, A. Cesarini, J. L. Christiansen, L. Ciupik, E. Collins-Hughes, M. P. Connolly, W. Cui, R. Dickherber, C. Duke, M. Errando, A. Falcone, J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, K. Gibbs, G. H. Gillanders, S. Godambe, S. Griffin, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, H. Huan, G. Hughes, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, H. Krawczynski, F. Krennrich, M. J. Lang, M. Lyutikov, A. S. Madhavan, G. Maier, P. Majumdar, S. Mcarthur, A. Mccann, M. Mccutcheon, P. Moriarty, R. Mukherjee, P. Nuñez, R. A. Ong, M. Orr, A. N. Otte, N. Park, J. S. Perkins, P. T. Reynolds, E. Roache, J. Rose, J. Ruppel, D. B. Saxon, M. Schroedter, G. H. Sembroski, G. D. Şentürk, A. W. Smith, D. Staszak, G. Tešić, M. Theiling, S. Thibadeau, K. Tsurusaki, J. Tyler, A. Varlotta, V. V. Vassiliev, S. Vincent, M. Vivier, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, B. Zitzer
Physics
We report the detection of pulsed gamma rays from the Crab pulsar at energies above 100 giga–electron volts (GeV) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) array of atmospheric Cherenkov telescopes. The detection cannot be explained on the basis of current pulsar models. The photon spectrum of pulsed emission between 100 mega–electron volts and 400 GeV is described by a broken power law that is statistically preferred over a power law with an exponential cutoff. It is unlikely that the observation can be explained by invoking curvature radiation as the origin of the observed gamma rays above …
Paleomagnetism And Investigation Of 40 Ma Lavas, Liverpool Range, New South Whales, Australia, Nathan M. Padilla
Paleomagnetism And Investigation Of 40 Ma Lavas, Liverpool Range, New South Whales, Australia, Nathan M. Padilla
Physics
The main focus of this project is the continued study of a reversal of the earth’s magnetic field recorded from lavas in the Liverpool Range of New South Whales, Australia. This reverse-to-normal transition, recently dated at ~40 Ma, was first reported in Nature in 1986. [2] In March 2011 some 200+ cores were drilled from several sections about the volcanic range—Jemmy’s Creek, Bald Hill, Rock Creek, Yarraman, and Coolah Tops Road. Here we focus on paleomagnetic findings from samples drilled from the most extensive section, that being along the trail near Jemmy’s Creek. Results from alternating field demagnetization show the …
Quantification Of Nitrate Sources And Sinks Using A Water Quality Network In Morro Bay Estuary, California, Johanna Nadia Jean Weston
Quantification Of Nitrate Sources And Sinks Using A Water Quality Network In Morro Bay Estuary, California, Johanna Nadia Jean Weston
Master's Theses
Using an instrumented water quality network in Morro Bay Estuary, California from 2007 to 2010 (15 min sampling frequency), this study addressed the two objectives of constructing a nitrate budget and assessing the influence of sampling frequency on water quality parameters. These two objectives led to the submission of an original report of research (Appendix A) and a note (Appendix B) to peer-reviewed journals.
The first objective was to characterize the high spatial and temporal variation in physical parameters and nitrate concentrations and to construct a nitrate budget quantifying sources and sinks of nitrate from the ocean, streams, and groundwater, …
Radio Frequency Noise Effects On The Cern Large Hadron Collider Beam Diffusion, Themis Mastoridis, P. Baudrenghien, A. Butterworth, J. Molendijk, C. Rivetta, J.D. Fox
Radio Frequency Noise Effects On The Cern Large Hadron Collider Beam Diffusion, Themis Mastoridis, P. Baudrenghien, A. Butterworth, J. Molendijk, C. Rivetta, J.D. Fox
Physics
No abstract provided.
Numerical Ocean Modeling And Simulation With Cuda, Jason Mak, Paul Choboter, Chris Lupo
Numerical Ocean Modeling And Simulation With Cuda, Jason Mak, Paul Choboter, Chris Lupo
Computer Science and Software Engineering
ROMS is software that models and simulates an ocean region using a finite difference grid and time stepping. ROMS simulations can take from hours to days to complete due to the compute-intensive nature of the software. As a result, the size and resolution of simulations are constrained by the performance limitations of modern computing hardware. To address these issues, the existing ROMS code can be run in parallel with either OpenMP or MPI. In this work, we implement a new parallelization of ROMS on a graphics processing unit (GPU) using CUDA Fortran. We exploit the massive parallelism offered by modern …
Loss Of Landau Damping In The Lhc, E. Shaposhnikova, T. Argyropoulos, T. Bohl, C. Bhat, P. Baudrenghien, A. Butterworth, T. Mastoridis, J. Esteban Muller, G. Papotti, J. Tuckmantel, W. Venturini Delsolaro, U. Wehrle
Loss Of Landau Damping In The Lhc, E. Shaposhnikova, T. Argyropoulos, T. Bohl, C. Bhat, P. Baudrenghien, A. Butterworth, T. Mastoridis, J. Esteban Muller, G. Papotti, J. Tuckmantel, W. Venturini Delsolaro, U. Wehrle
Physics
Loss of Landau damping leading to a single bunch longitudinal instability has been observed in the LHC during the ramp and on the 3.5 TeV flat top for small injected longitudinal emittances. The first measurements are in reasonable agreement with the threshold calculated for the expected longitudinal reactive impedance budget of the LHC as well as with the threshold dependence on beam energy. The cure is a controlled longitudinal emittance blow-up during the ramp which for a constant threshold through the cycle should provide an emittance proportional to the square root of energy.
Longitudinal Emittance Blow-Up In The Lhc, P. Baudrenghien, A. Butterworth, M. Jaussi, T. Mastoridis, G. Papotti, E. Shaposhnikova, J. Tuckmantel
Longitudinal Emittance Blow-Up In The Lhc, P. Baudrenghien, A. Butterworth, M. Jaussi, T. Mastoridis, G. Papotti, E. Shaposhnikova, J. Tuckmantel
Physics
The LHC relies on Landau damping for longitudinal stability. To avoid decreasing the stability margin at high energy, the longitudinal emittance must be continuously increased during the acceleration ramp. Longitudinal blow-up provides the required emittance growth. The method was implemented through the summer of 2010. We inject band-limited RF phase-noise in the main accelerating cavities during the whole ramp of about 11 minutes. Synchrotron frequencies change along the energy ramp, but the digitally created noise tracks the frequency change. The position of the noise-band, relative to the nominal synchrotron frequency, and the bandwidth of the spectrum are set by pre-defined …
An Axiomatic Approach To The Non-Linear Theory Of Generalized Functions And Consistency Of Laplace Transforms, Todor D. Todorov
An Axiomatic Approach To The Non-Linear Theory Of Generalized Functions And Consistency Of Laplace Transforms, Todor D. Todorov
Mathematics
We offer an axiomatic definition of a differential algebra of generalized functions over an algebraically closed non-Archimedean field. This algebra is of Colombeau type in the sense that it contains a copy of the space of Schwartz distributions. We study the uniqueness of the objects we define and the consistency of our axioms. Next, we identify an inconsistency in the conventional Laplace transform theory. As an application we offer a free of contradictions alternative in the framework of our algebra of generalized functions. The article is aimed at mathematicians, physicists and engineers who are interested in the non-linear theory of …
Projection Of Diffracted Optical Atom Traps, Jeremy Kruger
Projection Of Diffracted Optical Atom Traps, Jeremy Kruger
Physics
Theoretical calculations were performed for the projection of a diffraction pattern created by a pinhole through a single-lens system using vector diffraction theory and a combination of programs (MathCAD, Igor, etc.). The projected diffraction patterns were then experimentally created, recorded, and analyzed. This work is part of a larger collaboration with Dr. Kat Gillen, to trap and manipulate atoms in a Magneto Optical Trap (MOT) and to make further steps in the direction of Quantum Computing using trapped neutral atoms.
On Human Analyst Performance In Assisted Requirements Tracing: Statistical Analysis, A. Dekhtyar, O. Dekhtyar, J. Holden, D. Cuddeback, W. K. Kong
On Human Analyst Performance In Assisted Requirements Tracing: Statistical Analysis, A. Dekhtyar, O. Dekhtyar, J. Holden, D. Cuddeback, W. K. Kong
Computer Science and Software Engineering
Assisted requirements tracing is a process in which a human analyst validates candidate traces produced by an automated requirements tracing method or tool. The assisted requirements tracing process splits the difference between the commonly applied time-consuming, tedious, and error-prone manual tracing and the automated requirements tracing procedures that are a focal point of academic studies. In fact, in software assurance scenarios, assisted requirements tracing is the only way in which tracing can be at least partially automated. In this paper, we present the results of an extensive 12 month study of assisted tracing, conducted using three different tracing processes at …
A Sporadic Low‐Velocity Layer Atop The Western U.S. Mantle Transition Zone And Short‐Wavelength Variations In Transition Zone Discontinuities, B. Schmandt, K.G. Dueker, S.M. Hansen, John J. Jasbinsek, Z. Zhang
A Sporadic Low‐Velocity Layer Atop The Western U.S. Mantle Transition Zone And Short‐Wavelength Variations In Transition Zone Discontinuities, B. Schmandt, K.G. Dueker, S.M. Hansen, John J. Jasbinsek, Z. Zhang
Physics
Teleseismic receiver function analysis of data from six dense arrays in the western U.S. is used to investigate mantle transition zone (MTZ) discontinuities and the prevalence of a low‐velocity layer atop the 410 km discontinuity (410‐LVL). Negative polarity Ps arrivals indicative of a low‐velocity layer with a top 25–60 km above the 410 are identified in 8–11 out of 18 stacks of receiver functions from highly sampled back azimuth corridors. The 410‐LVL is interpreted as partial melt resulting from upwelling of hydrated mantle across a water solubility contrast at the 410. The 669 km mean depth of the 660 km …
Automated Systems And Methods For Testing Infrared Cameras, Gary B. Hughes
Automated Systems And Methods For Testing Infrared Cameras, Gary B. Hughes
Statistics
Systems and methods are disclosed herein to provide automated testing on infrared image data to detect image quality defects. For example, in accordance with an embodiment of the present invention, image processing algorithms are disclosed to generate an image quality metric that may be compared to one or more thresholds to perform an automated test for image quality defects. For example, the image quality metric may be compared to two thresholds to determine if the corresponding infrared sensor or infrared camera is defective or not due to image quality or requires further manual inspection by test personnel.
Polysat’S Next Generation Avionics Design, Greg Manyak, John M. Bellardo
Polysat’S Next Generation Avionics Design, Greg Manyak, John M. Bellardo
Computer Science and Software Engineering
The CubeSat platform provides a unique challenge for flight software design due to the incredible size and power constraints. A number of tradeoffs must be made to balance effectiveness, fault tolerance, and cost. These basic requirements have been combined with the lessons learned from Cal Poly’s past 8-bit avionics system to design a significant revision based around a 32-bit microprocessor running Linux. This work analyzes both generations of avionics design, including a discussion of major design principles that are relevant to other CubeSat missions.
Icodes: A Load-Planning System That Demonstrates The Value Of Ontologies In The Realm Of Logistical Command And Control (C2), Kym J. Pohl, Peter Morosoff
Icodes: A Load-Planning System That Demonstrates The Value Of Ontologies In The Realm Of Logistical Command And Control (C2), Kym J. Pohl, Peter Morosoff
Collaborative Agent Design (CAD) Research Center
No abstract provided.
The Role Of Llnl's Fast Calibration Facility In Diagnosing Nif Fusion Plasmas, Joshua G. Thompson, Carey Scott, Greg V. Brown
The Role Of Llnl's Fast Calibration Facility In Diagnosing Nif Fusion Plasmas, Joshua G. Thompson, Carey Scott, Greg V. Brown
STAR Program Research Presentations
The Fusion and Astrophysics (FAST) Calibration and Diagnostic Facility uses the original Electron Beam Ion Trap (EBIT-I) to profile x-ray filters that are used in the Dante Soft X-Ray Diagnostic at the National Ignition Facility (NIF). FAST has an advantage over any other facility not only for its high accuracy, but also for its proximity to NIF in the Lawrence Livermore National Laboratory (LLNL). This makes for highly accurate and near-instantaneous filter calibration turnover.
EBIT-I was first constructed to create, trap, and observe static highly charged ions (HCIs) and conduct experimental astrophysics (creating an x-ray spectroscopy catalogue of ions). To …
Rock Porosity Analysis Using High Resolution X-Ray Tomography, Leo Groner, Dula Parkinson, Katya Bazilevskaya
Rock Porosity Analysis Using High Resolution X-Ray Tomography, Leo Groner, Dula Parkinson, Katya Bazilevskaya
STAR Program Research Presentations
Understanding rock porosity, the fraction of rock volume that is in pores, is a key to modeling weathering and flow of water, petroleum and CO2 through geological structures. Weathering of rocks affects the CO2 cycle, nutrient cycle and soil formation. Rock porosity affects water flow rates and, in turn, affects weathering. Avizo software was used to explore, visualize and measure the reconstructed high-resolution X-ray micro-tomography data collected from scanned rocks. Many Avizo approaches were tried before arriving at an acceptable process to determine their porosity characteristics. Porosity dynamics are affected by weathering and lithification. At micron resolution, the image is …
Vapor Liquid Solid Growths Of Germanium And Gallium Antimonide Nanowires, Ralph Alvarez, Esmeralda Arreola, Michael Oye, Meyya Meyyappan
Vapor Liquid Solid Growths Of Germanium And Gallium Antimonide Nanowires, Ralph Alvarez, Esmeralda Arreola, Michael Oye, Meyya Meyyappan
STAR Program Research Presentations
Determining the optimal growth parameters for germanium (Ge) and gallium antimonide (GaSb) nanowires is the focus of this research. Given the fact that nano materials behave differently from their bulk counterparts we are researching some variables that influence nanowire diameter and length such as temperature, ramp rate, gas flow rate, and catalyst particle size. Based on the nano material size which is typically a few 10s of nanometers wide, these nano materials can be engineered to take advantage of their optical properties. Specifically the infrared (IR) response of Ge and GaSb nanowires are directly controllable based on their geometry. Fine …
Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown
Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown
STAR Program Research Presentations
Astrophysicists use radiation to investigate the physics controlling a variety of celestial sources, including stellar atmospheres, black holes, and binary systems. By measuring the spectrum of the emitted radiation, astrophysicists can determine a source’s temperature and composition. Accurate atomic data are needed for reliably interpreting these spectra. Here we present an overview of how LLNL’s EBIT facility is used to put the atomic data on sound footing for use by the high energy astrophysics community.
Relationships Between Snow Pack, Soil Moisture, And Forest Greenness: Implications For Smap, Jordan Anderson, Noah Molotch, Bin Guan
Relationships Between Snow Pack, Soil Moisture, And Forest Greenness: Implications For Smap, Jordan Anderson, Noah Molotch, Bin Guan
STAR Program Research Presentations
Snowpack in the arid/semi-arid western United States is a critical element of the hydrologic cycle as water is stored in the winter and released in the spring and summer. The warmer seasons rely heavily on this water source for various purposes including economic (farming), environmental and recreational demands. Moderate Imaging Spectroradiometer (MODIS) sensors were used in this project to measure seasonal variability in global vegetation phenology and productivity. MODIS data was used to calculate Normalized Difference Vegetation Index (NDVI) to estimate net primary production of subalpine forests in the Sierra Nevada mountain range. Preliminary results indicate that variability in forest …
Assessing Laser Lifetime Test Performance, Joe Weichman, Hamid Hemmati, Malcolm Wright
Assessing Laser Lifetime Test Performance, Joe Weichman, Hamid Hemmati, Malcolm Wright
STAR Program Research Presentations
Assessing expected component lifetime is necessary in developing instruments for future space-flight projects to ensure long term operation in the challenging environment. Although semiconductor diode lasers have widespread use in terrestrial applications, their use in space is still an emerging technology that requires on-going testing to demonstrate their capability. The project called for re-establishing the test setup for assessing lifetime performance of 20 continuously running 200mW 830 nm diode lasers. These lasers underwent previous testing based on parameters for NuSTAR’s laser metrology system, and met the six month lifetime project requirements under nominal operating conditions. Laser testing is currently underway …
Beam Halo Measurements At The Spear3 Synchrotron, Jonathan B. Kamp, Jeff Corbett
Beam Halo Measurements At The Spear3 Synchrotron, Jonathan B. Kamp, Jeff Corbett
STAR Program Research Presentations
It is known that in an intense beam, particles will start to spread from the core of the beam. This spreading of particles outside the core beam is known as a halo. The affects of unwanted particles spreading from a core beam can have detrimental effects to nearby machinery and personal. The issue with understanding beam halo lies with its low intensity compared to the core beam. In order to analyze the halo, we will use a digital micro mirror array device (DMA) to block out the core of a visible beam coming from the SPEAR3 synchrotron and image the …
Effects Of Ambient Gases On Icf Target Capsules, Bryan Chambers, Steve Letts, Michael Stadermann
Effects Of Ambient Gases On Icf Target Capsules, Bryan Chambers, Steve Letts, Michael Stadermann
STAR Program Research Presentations
We researched how the chemical and physical properties of a plasma polymer fuel capsule change as they are exposed to ambient gases. The fuel capsules contain the deuterium fuel inside them, they serve as the outer shell for the fuel and act as a ablator for the process. If they are reactive or diffusive with the atmosphere this can change their mass and effect the outcome of the fusion shots performed at the National Ignition Facility where High Powered Lasers are incident upon a gold hohlraum containing a capsule. We discovered that nitrogen and water vapor diffuse into the material …