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Articles 151 - 180 of 313
Full-Text Articles in Instrumentation
The Green Bank Observatory Piktograph, Katelyn Flanagan
The Green Bank Observatory Piktograph, Katelyn Flanagan
West Virginia Connection
For this portion of the materials, I included two “Piktographs” for students to use as a resource for their research for the final assignment. The first is one on the contributions specifically from West Virginia to the space race. It includes specific people from West Virginia and their contributions to this portion of our nation’s history. This way students are able to make home connections to West Virginia. The second Piktograph is one specifically on The Green Bank Observatory located in Green Bank, WV. It is home to the first radio telescope, as well as being the first national astronomy …
The Green Bank Observatory And The Space Race - Introduction, Katelyn Flanagan
The Green Bank Observatory And The Space Race - Introduction, Katelyn Flanagan
West Virginia Connection
For this portion of the materials, I included two “Piktographs” for students to use as a resource for their research for the final assignment. The first is one on the contributions specifically from West Virginia to the space race. It includes specific people from West Virginia and their contributions to this portion of our nation’s history. This way students are able to make home connections to West Virginia. The second Piktograph is one specifically on The Green Bank Observatory located in Green Bank, WV. It is home to the first radio telescope, as well as being the first national astronomy …
Data Mining By Grid Computing In The Search For Extrasolar Planets, Oisin Creaner [Thesis]
Data Mining By Grid Computing In The Search For Extrasolar Planets, Oisin Creaner [Thesis]
Doctoral
A system is presented here to provide improved precision in ensemble differential photometry. This is achieved by using the power of grid computing to analyse astronomical catalogues. This produces new catalogues of optimised pointings for each star, which maximise the number and quality of reference stars available. Astronomical phenomena such as exoplanet transits and small-scale structure within quasars may be observed by means of millimagnitude photometric variability on the timescale of minutes to hours. Because of atmospheric distortion, ground-based observations of these phenomena require the use of differential photometry whereby the target is compared with one or more reference stars. …
Improving Cavity Enhanced Spectroscopy Of Molecular Ions In The Mid-Infrared With Up-Conversion Detection And Brewster-Plate Spoilers, Charles R. Markus, Adam J. Perry, James N. Hodges, Benjamin J. Mccall
Improving Cavity Enhanced Spectroscopy Of Molecular Ions In The Mid-Infrared With Up-Conversion Detection And Brewster-Plate Spoilers, Charles R. Markus, Adam J. Perry, James N. Hodges, Benjamin J. Mccall
Chemistry & Biochemistry Faculty Publications
The performance of sensitive spectroscopic methods in the mid-IR is often limited by fringing due to parasitic etalons and the background noise in mid-infrared detectors. In particular, the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS), which is capable of determining the frequencies of strong rovibrational transitions of molecular ions with sub-MHz uncertainty, needs improved sensitivity in order to probe weaker transitions. In this work, we have implemented up-conversion detection with NICE-OHVMS in the 3.2 - 3.9 μm region to enable the use of faster and more sensitive detectors which cover visible wavelengths. The higher bandwidth enabled …
Joint Hierarchical Models For Sparsely Sampled High-Dimensional Lidar And Forest Variables, Andrew O. Finley, Sudipto Banerjee, Yuzhen Zhou, Bruce D. Cook, Chad Babcock
Joint Hierarchical Models For Sparsely Sampled High-Dimensional Lidar And Forest Variables, Andrew O. Finley, Sudipto Banerjee, Yuzhen Zhou, Bruce D. Cook, Chad Babcock
United States National Aeronautics and Space Administration: Publications
Recent advancements in remote sensing technology, specifically Light Detection and Ranging (LiDAR) sensors, provide the data needed to quantify forest characteristics at a fine spatial resolution over large geographic domains. From an inferential standpoint, there is interest in prediction and interpolation of the often sparsely sampled and spatially misaligned LiDAR signals and forest variables. We propose a fully process-based Bayesian hierarchical model for above ground biomass (AGB) and LiDAR signals. The processbased framework offers richness in inferential capabilities, e.g., inference on the entire underlying processes instead of estimates only at pre-specified points. Key challenges we obviate include misalignment between the …
The Remote Observatories Of The Southeastern Association For Research In Astronomy (Sara), William C. Keel, Terry D. Oswalt, Peter Mack, Gary Henson, Todd Hillwig, Et Al.
The Remote Observatories Of The Southeastern Association For Research In Astronomy (Sara), William C. Keel, Terry D. Oswalt, Peter Mack, Gary Henson, Todd Hillwig, Et Al.
Publications
We describe the remote facilities operated by the Southeastern Association for Research in Astronomy (SARA) , a consortium of colleges and universities in the US partnered with Lowell Observatory, the Chilean National Telescope Allocation Committee, and the Instituto de Astrofísica de Canarias. SARA observatories comprise a 0.96 m telescope at Kitt Peak, Arizona; one of 0.6 m aperture on Cerro Tololo, Chile; and the 1 m Jacobus Kapteyn Telescope at the Roque de los Muchachos, La Palma, Spain. All are operated using standard VNC or Radmin protocols communicating with on-site PCs. Remote operation offers considerable flexibility in scheduling, allowing long-term …
High Power Optically Pumped Semiconductor Lasers For Sodium Guidestar Applications, Shawn W. Hackett
High Power Optically Pumped Semiconductor Lasers For Sodium Guidestar Applications, Shawn W. Hackett
Optical Science and Engineering ETDs
Optically pumped semiconductor lasers (OPSLs) are shown to provide a much more compact and less expensive source for illumination of the sodium layer of the mesosphere for use as a sodium laser guidestar via single and two photon excitation schemes. This represents a revolution in laser guidestar technology as the cost, size, and power requirements for a laser guidestar system are shown to have been decreased by an order of magnitude with guidestar performance shown to be similar to previous sources. Sodium laser guidestar sources for broadband simultaneous illumination of multiple lines are developed and simulated. Simulations are then compared …
Earthkam: A Classroom With The Ultimate View!, Jeremy Frost, Tyler Finley, Tim Klug, Angela Burke, Robert Griffin
Earthkam: A Classroom With The Ultimate View!, Jeremy Frost, Tyler Finley, Tim Klug, Angela Burke, Robert Griffin
Von Braun Symposium Student Posters
No abstract provided.
Improving The Efficiency Of Gravitational Wave Detection, Jessica Page, Tyson Littenberg
Improving The Efficiency Of Gravitational Wave Detection, Jessica Page, Tyson Littenberg
Von Braun Symposium Student Posters
No abstract provided.
Designing An Anti-Coincidence Shielding System For The Alfred Project, Active Luminescence For X-Ray Emission Detection (Alfred) Team, Francis Wessling
Designing An Anti-Coincidence Shielding System For The Alfred Project, Active Luminescence For X-Ray Emission Detection (Alfred) Team, Francis Wessling
Von Braun Symposium Student Posters
No abstract provided.
Examination Of Resonant Modes In Microwave Cavities, Sophia Schwalbe, Gianpaolo Carosi
Examination Of Resonant Modes In Microwave Cavities, Sophia Schwalbe, Gianpaolo Carosi
Student Works
The Axion Dark Matter eXperiment (ADMX) looks to detect dark matter axion particles by using microwave cavities in a high magnetic eld to convert the axion's mass energy to a detectable photon. The photon frequency corresponds to the axion mass. Tuning elements in the cavities allow the resonant frequency to be changed but only certain modes couple to the axion. Interactions with additional resonant modes that do not couple to the axion cause unobservable regions in the frequency range. This research investigated new methods to move the additional resonant modes in order to observe these regions.
High Altitude Cosmic Ray Detection, Jordan D. Van Nest
High Altitude Cosmic Ray Detection, Jordan D. Van Nest
2017 Academic High Altitude Conference
Cosmic rays are high energy atomic nuclei travelling near the speed of light that collide with atoms and molecules in Earth’s upper atmosphere (primarily with nitrogen and oxygen), breaking down into a shower of particles of various energies in the stratosphere. As they travel earthward, these particles continue to break down and lose energy which results in relatively little ionizing radiation reaching the surface. Due to the scattering of cosmic rays, the angle at which the rays enter the atmosphere can affect the number and energies of ionizing particles detected at various altitudes. When using a standard Geiger counter on …
Studying Solar Limb Darkening In H-Alpha With A Coronado Pst, Jessica N. Farrell, Jennifer Birriel
Studying Solar Limb Darkening In H-Alpha With A Coronado Pst, Jessica N. Farrell, Jennifer Birriel
Celebration of Student Scholarship Poster Sessions Archive
No abstract provided.
An Apparatus For Studying Electrical Breakdown In Liquid Helium At 0.4 K And Testing Electrode Materials For The Neutron Electric Dipole Moment Experiment At The Spallation Neutron Source, T. M. Ito, J. C. Ramsey, W. Yao, D. H. Beck, V. Cianciolo, S. M. Clayton, Christopher B. Crawford, S. A. Currie, B. W. Filippone, W. C. Griffith, M. Makela, R. Schmid, G. M. Seidel, Z. Tang, D. Wagner, W. Wei, S. E. Williamson
An Apparatus For Studying Electrical Breakdown In Liquid Helium At 0.4 K And Testing Electrode Materials For The Neutron Electric Dipole Moment Experiment At The Spallation Neutron Source, T. M. Ito, J. C. Ramsey, W. Yao, D. H. Beck, V. Cianciolo, S. M. Clayton, Christopher B. Crawford, S. A. Currie, B. W. Filippone, W. C. Griffith, M. Makela, R. Schmid, G. M. Seidel, Z. Tang, D. Wagner, W. Wei, S. E. Williamson
Physics and Astronomy Faculty Publications
We have constructed an apparatus to study DC electrical breakdown in liquid helium at temperatures as low as 0.4 K and at pressures between the saturated vapor pressure and ∼600 Torr. The apparatus can house a set of electrodes that are 12 cm in diameter with a gap of 1–2 cm between them, and a potential up to ±50 kV can be applied to each electrode. Initial results demonstrated that it is possible to apply fields exceeding 100 kV/cm in a 1 cm gap between two electropolished stainless steel electrodes 12 cm in diameter for a wide range of pressures …
Probing The Fitting Accuracy Of Active Galaxy Spectra, Aaron T. Line
Probing The Fitting Accuracy Of Active Galaxy Spectra, Aaron T. Line
Physics
Prior to this study, Dr. Vardha N. Bennert and collaborators selected a sample of ~100 local active galaxies to study the relationships between black hole mass and host galaxy properties. The broad Hβ width is necessary to determine black hole mass. This value is determined using a spectral decomposition code was scripted in IDL by Dr. Daeseong Park. The script fit spectral features and collected data for properties such as width of emission lines and continuum contribution percentages. The results were logged for further analysis.
To probe the accuracy of the fitting process, artificial spectra were created and fitted to …
A Search For Brief Optical Flashes Associated With The Seti Target Kic 8462852, P. T. Reynolds, Et Al
A Search For Brief Optical Flashes Associated With The Seti Target Kic 8462852, P. T. Reynolds, Et Al
Physical Sciences Publications
The F-type star KIC 8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately , is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general.
Verifying The Associations Of Fermi Source3fgl 2015.6+3709, Qiana Hunt
Verifying The Associations Of Fermi Source3fgl 2015.6+3709, Qiana Hunt
Von Braun Symposium Student Posters
No abstract provided.
Searching For Terrestrial Gamma-Ray Flashes Via Lightning And The Fermi Space Telescope, Kareem Omar
Searching For Terrestrial Gamma-Ray Flashes Via Lightning And The Fermi Space Telescope, Kareem Omar
Von Braun Symposium Student Posters
No abstract provided.
Design And Fabrication Of Liquid Scintillator Counter, Andrea Calderon Saucedo, John L. Orrell
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 …
Resolving Emission Lines Of Sodiumlike Fe Xvi Using Ebit, Sandi Lavito
Resolving Emission Lines Of Sodiumlike Fe Xvi Using Ebit, Sandi Lavito
STAR Program Research Presentations
High resolution crystal spectrometers on sounding rockets and orbiting satellites, such as the Solar Maximum Mission, show strong X-ray emission from the n= 3 to 2 transitions in neon-like Fe XVII. Two of the strongest lines are the 3d to 2p resonance and inter combination lines at 15.01 Å (3C) and 15.26 Å (3D).
Intensity ratios of these solar lines range from ~ 1.6 to 2.8. The lower ratios are a result of a line from Na-like Fe XVI inner shell satellite line blending with the Fe XVII inter combination line, 3D. The wavelength of the Na-like line is not …
Retrieval Of Aerosol Microphysical Properties From Aeronet Photopolarimetric Measurements, Xiaoguang Xu
Retrieval Of Aerosol Microphysical Properties From Aeronet Photopolarimetric Measurements, Xiaoguang Xu
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Atmospheric aerosols play an important role in earth climate by scattering and absorbing solar and terrestrial radiation, and indirectly through altering the cloud formation, life- time, and radiative properties. However, accurate quantification of these effects is in no small part hindered by our limited knowledge about the particle size distribution (PSD) and refractive index, the aerosol microphysical properties essentially pertain to aerosol optical and cloud-forming properties. The research goal of this thesis is to obtain the aerosol microphysical properties of both fine and coarse modes from the polarimetric solar radiation measured by the SunPhotometer of the Aerosol Robotic Network (AERONET). …
Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa
Detecting Cosmic Rays Using Cemos Sensors In Consumer Devices, Matthew M. Plewa
2017 Academic High Altitude Conference
Since the time of Victor Hess and his balloon flight that demonstrated that cosmic rays increased with altitude, new detection methods have become widely available to be used on current day flights. One such method is to utilize CCDs with long duration exposures. During the exposures the CCD is exposed to cosmic rays which then leave a track. This phenomenon is caused by the CCD's inability to distinguish between photons of light and charged particles. Such tracks can then be separated from the CCD's background noise and classified.
Directional Camera Control On High Altitude Balloons, Matthew M. Plewa, Brent Scharlau
Directional Camera Control On High Altitude Balloons, Matthew M. Plewa, Brent Scharlau
2017 Academic High Altitude Conference
The research reported in this paper examined the design and control of a gimbal for solar eclipse tracking and video recording. The gimbal design required 3 axes of rotation to allow for full range of motion. Utilizing individual brushless motors for each of the axes ensure minimum rotational requirements on each axes. In controlling the gimbal, both a mathematical and visual method were utilized. The mathematical method is a modified version of what is currently used for solar array pointing. The visual method looks at where the position of the sun is within the image and determines what angle changes …
Gps Phase Scintillation At High Latitudes During Geomagnetic Storms Of 7–17 March 2012 – Part 1: The North American Sector, P. Prikryl, R. Ghoddousi-Fard, E. G. Thomas, J. M. Ruohoniemi, S. G. Shepherd
Gps Phase Scintillation At High Latitudes During Geomagnetic Storms Of 7–17 March 2012 – Part 1: The North American Sector, P. Prikryl, R. Ghoddousi-Fard, E. G. Thomas, J. M. Ruohoniemi, S. G. Shepherd
Dartmouth Scholarship
During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7–17 March 2012 caused geomagnetic storms that strongly affected high-latitude ionosphere in the Northern and Southern Hemisphere. GPS phase scintillation was observed at northern and southern high latitudes by arrays of GPS ionospheric scintillation and TEC monitors (GISTMs) and geodetic-quality GPS receivers sampling at 1 Hz. Mapped as a function of magnetic latitude and magnetic local time, regions of enhanced scintillation are identified in the context of coupling processes between the solar wind and the magnetosphere–ionosphere system. Large southward IMF and …
Defining The Circumstellar Habitable Zone, Blake Cervetti, Joanna Mccall
Defining The Circumstellar Habitable Zone, Blake Cervetti, Joanna Mccall
DePaul Discoveries
The study of habitable exoplanets is a rapidly expanding field in astronomy. Exoplanets are planets that orbit stars other than our own sun. One of the keys to knowing whether or not an exoplanet is habitable is by studying the circumstellar habitable zone, or CHZ. Over the past several years, the defined limits of the CHZ have become susceptible to change as new parameters and factors are found to affect a planets habitability. There are many factors that affect its habitability, including the composition of the star, the mass of the planet, the planets atmosphere, etc. Our focus is divided …
Dual-Spacecraft Reconstruction Of A Three-Dimensional Magnetic Flux Rope At The Earth's Magnetopause, H. Hasegawa, B. U. Ö. Sonnerup, S. Eriksson, T. K. M. Nakamura
Dual-Spacecraft Reconstruction Of A Three-Dimensional Magnetic Flux Rope At The Earth's Magnetopause, H. Hasegawa, B. U. Ö. Sonnerup, S. Eriksson, T. K. M. Nakamura
Dartmouth Scholarship
We present the first results of a data analysis method, developed by Sonnerup and Hasegawa (2011), for reconstructing three-dimensional (3-D), magnetohydrostatic structures from data taken as two closely spaced satellites traverse the structures. The method is applied to a magnetic flux transfer event (FTE), which was encountered on 27 June 2007 by at least three (TH-C, TH-D, and TH-E) of the five THEMIS probes near the subsolar magnetopause. The FTE was sandwiched between two oppositely directed reconnection jets under a southward interplanetary magnetic field condition, consistent with its generation by multiple X-line reconnection. The recovered 3-D field indicates that a …
Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker
Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker
School of Natural Resources: Faculty Publications
Vegetation productivity metrics such as gross primary production (GPP) at the canopy scale are greatly affected by the efficiency of using absorbed radiation for photosynthesis, or light use efficiency (LUE). Thus, close investigation of the relationships between canopy GPP and photosynthetically active radiation absorbed by vegetation is the basis for quantification of LUE. We used multiyear observations over irrigated and rainfed contrasting C3 (soybean) and C4 (maize) crops having different physiology, leaf structure, and canopy architecture to establish the relationships between canopy GPP and radiation absorbed by vegetation and quantify LUE. Although multiple LUE definitions are reported in the literature, …
A Fast Visible Infrared Imaging Radiometer Suite Simulator For Cloudy Atmospheres, Chao Liu, Ping Yang, Steven Platnick, Kerry G. Meyer, Chenxi Wang, Shouguo Ding
A Fast Visible Infrared Imaging Radiometer Suite Simulator For Cloudy Atmospheres, Chao Liu, Ping Yang, Steven Platnick, Kerry G. Meyer, Chenxi Wang, Shouguo Ding
Department of Earth and Atmospheric Sciences: Faculty Publications
A fast instrument simulator is developed to simulate the observations made in cloudy atmospheres by the Visible Infrared Imaging Radiometer Suite (VIIRS). The correlated k distribution technique is used to compute the transmissivities associated with absorbing atmospheric gases. The bulk scattering properties of ice clouds are based on the ice model used for the Moderate Resolution Imaging Spectroradiometer Collection 6 ice cloud products, and those ofwater clouds are computedwith the Lorenz-Mie theory. Two fast radiative transfer models based on precomputed ice cloud look-up tables are used for the VIIRS solar and infrared channels. The accuracy and efficiency of the fast …
Instrument For Precision Long-Term Ss-Decay Rate Measurements, M. J. Ware, Scott D. Bergeson, J. E. Ellsworth, M. Groesbeck, J. E. Hansen, D. Pace, J. Peatross
Instrument For Precision Long-Term Ss-Decay Rate Measurements, M. J. Ware, Scott D. Bergeson, J. E. Ellsworth, M. Groesbeck, J. E. Hansen, D. Pace, J. Peatross
Faculty Publications
We describe an experimental setup for making precision measurements of relative ß-decay rates of 22Na, 36Cl, 54Mn, 60Co, 90Sr, 133Ba, 137Cs, 152Eu, and 154Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM …
The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley
The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley
Publications
It takes years of effort employing the best telescopes and in- struments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of life- times of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual …