Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 53

Full-Text Articles in Physics

Uncertainty Associated With Modeling The Global Ionosphere, Janelle V. Jenniges, Ariel O. Acebal, Larry Gardner, Robert W. Schunk, Lie Zhu Dec 2010

Uncertainty Associated With Modeling The Global Ionosphere, Janelle V. Jenniges, Ariel O. Acebal, Larry Gardner, Robert W. Schunk, Lie Zhu

Physics Student Research

A study has been conducted of the effect that different physical assumptions have on global models of the electron density distribution. The study was conducted with the Ionosphere Forecast Model (IFM) and the Ionosphere Plasmasphere Model (IPM) developed by Utah State University. Both physics-based, time-dependent, global models use the same empirical models for the neutral atmosphere (MSIS) and neutral wind (Horizontal Wind Model, HWM), but the altitude range, thermal structure, number of ion species, and magnetic 2ield are different. The IFM covers the altitude range from 90-1400 km, calculates the densities for four ions (NO+, O2+, N2+, O+), has a ...


Statistical Analysis Of The Usu Lidar Data Set With Reference To Mesospheric Solar Response And Cooling Rate Calculation, With Analysis Of Statistical Issues Affecting The Regression Coefficients, Troy Alden Wynn Dec 2010

Statistical Analysis Of The Usu Lidar Data Set With Reference To Mesospheric Solar Response And Cooling Rate Calculation, With Analysis Of Statistical Issues Affecting The Regression Coefficients, Troy Alden Wynn

All Graduate Theses and Dissertations

Though the least squares technique has many advantages, its possible limitations as applied in the atmospheric sciences have not yet been fully explored in the literature. The assumption that the atmosphere responds either in phase or out of phase to the solar input is ubiquitous. However, our analysis found this assumption to be incorrect. If not properly addressed, the possible consequences are bias in the linear trend coefficient and attenuation of the solar response coefficient.

Using USU Rayleigh lidar temperature data, we found a significant phase offset to the solar input in the temperatures that varies ±5 years depending on ...


Spatial Light Dilution As A Technique For Conversion Of Solar Energy To Algal Biomass, Daniel J. Dye Dec 2010

Spatial Light Dilution As A Technique For Conversion Of Solar Energy To Algal Biomass, Daniel J. Dye

All Graduate Theses and Dissertations

A photobioreactor has been designed and developed to efficiently utilize solar irradiance through spatial dilution of sunlight. The concept of spatial light dilution is simple: incident sunlight is spread over a large surface area, thus reducing the photon flux density of the light. The implementation of this technique, however, is difficult. The reactor described within uses a new approach to spatial light dilution, utilizing recently-developed optical components to diffuse concentrated sunlight inside an algae culture. Preliminary productivity tests indicate a 2-3 fold increase in productivity per unit aperture (sunlight collection area) over a control reactor with direct-sunlight. Aperture productivity of ...


Symmetric Criticality In Classical Field Theory, Charles G. Torre Nov 2010

Symmetric Criticality In Classical Field Theory, Charles G. Torre

Charles G. Torre

This is a brief overview of work done by Ian Anderson, Mark Fels, and myself on symmetry reduction of Lagrangians and Euler-Lagrange equations, a subject closely related to Palais’ Principle of Symmetric Criticality. After providing a little history, I describe necessary and sufficient conditions on a group action such that reduction of a group-invariant Lagrangian by the symmetry group yields the correct symmetry-reduced Euler-Lagrange equations.


Oh And Oi Airglow Layer Modulation By Ducted Shortperiod Gravity Waves: Effects Of Trapping Altitude, J. B. Snively, V. P. Pasko, Michael J. Taylor Nov 2010

Oh And Oi Airglow Layer Modulation By Ducted Shortperiod Gravity Waves: Effects Of Trapping Altitude, J. B. Snively, V. P. Pasko, Michael J. Taylor

All Physics Faculty Publications

Perturbations to the OH and OI [O(1S) 557.7 nm] airglow layers by ducted gravity waves near the Brunt-Väisälä period are investigated using a 2-D numerical model. Airglow signatures of these waves are strongly determined by perturbations of O, O3, and H, which exhibit peak densities near and above mesopause. Strong periodic vertical wind components of short-period gravity waves induce opposite relative density perturbations above and below the layer density peaks. Airglow signatures for ducted waves depend on the specific vertical shapes and altitudes of the wave packets relative to ambient species density profiles; waves perturbing only ...


Characterization Of Pollen Particles Using Lidar, Leda Sox Oct 2010

Characterization Of Pollen Particles Using Lidar, Leda Sox

Graduate Student Posters

We have observed pollen in the local troposphere using the depolarization capabilities of a LIDAR (Light Detection and Ranging) system. The polarization characteristics of the received LIDAR signal, along with supplemental pollen forecast data, allowed me to characterize the shape of the pollen particles.


The First Ten Months Of Investigation Of Gravity Waves And Temperature Variability Over The Andes, Jonathan Pugmire, Neal Criddle, Michael J. Taylor, P. D. Pautet, Yucheng Zhao Oct 2010

The First Ten Months Of Investigation Of Gravity Waves And Temperature Variability Over The Andes, Jonathan Pugmire, Neal Criddle, Michael J. Taylor, P. D. Pautet, Yucheng Zhao

Graduate Student Posters

The Andes region is an excellent natural laboratory for investigating gravity wave influences on the Upper Mesospheric and Lower Thermospheric (MLT) dynamics. The instrument suite that comprised the very successful Maui-MALT program was recently re-located to a new Andes Lidar Observatory (ALO) located at Cerro Pachon, Chile to obtain in-depth seasonal measurements of MLT dynamics over the Andes mountains. As part of the instrument set the Utah State University CEDAR Mesospheric Temperature Mapper (MTM) has operated continuously since August 2009 measuring the near infrared OH(6,2) band and the O2(0,1) Atmospheric band intensity and temperature perturbations. This ...


First Year Investigation Of Gravity Waves And Temperature Variability Over The Andes, Jonathan Pugmire, Neal R. Criddle, Michael J. Taylor, Dominique Pautet, Yucheng Zhao Oct 2010

First Year Investigation Of Gravity Waves And Temperature Variability Over The Andes, Jonathan Pugmire, Neal R. Criddle, Michael J. Taylor, Dominique Pautet, Yucheng Zhao

Graduate Student Presentations

The Andes region is an excellent natural laboratory for investigating gravity wave influences on the Upper Mesospheric and Lower Thermospheric (MLT) dynamics: during the summer months the dominant gravity waves result from deep convection arising from severe thunderstorms over the continent to the east. In winter this convective activity is expected to be replaced by strong orographic forcing due to intense prevailing zonal winds blowing eastward from the Pacific Ocean and suddenly encountering the towering Andes mountain range (6000m). This creates large amplitude mountain waves that have been measured well into the stratosphere and most recently penetrate occasionally into the ...


Comparison Of Flight And Ground Tests Of Environmental Degradation Of Misse-6 Suspecs Materials, Jr Dennison, John Prebola, Amberly Evans Jensen, Joshua L. Hodges Sep 2010

Comparison Of Flight And Ground Tests Of Environmental Degradation Of Misse-6 Suspecs Materials, Jr Dennison, John Prebola, Amberly Evans Jensen, Joshua L. Hodges

Conference Proceedings

The effects of prolonged exposure to the LEO space environment and charge-enhanced contamination on optical, thermal, and electron emission and transport properties of common spacecraft materials has been investigated by comparing pre- and post-flight characterization measurements. The State of Utah Space Environment & Contamination Study (SUSpECS) deployed in March 2008 on board the Materials International Space Station Experiment (MISSE-6) payload, was exposed for ~18 months on the exterior of the International Space Station (ISS), before retrieval in September 2009. A total of 165 samples were mounted on three separate SUSpECS ...


Physics Lesson Plan: How Far And Fast Does It Travel?, Getaway Special Team 2010 Sep 2010

Physics Lesson Plan: How Far And Fast Does It Travel?, Getaway Special Team 2010

Education and Outreach

No abstract provided.


Earth Systems Lesson Plan: Size And Forces Of The Solar System, Getaway Special Team 2010 Sep 2010

Earth Systems Lesson Plan: Size And Forces Of The Solar System, Getaway Special Team 2010

Education and Outreach

No abstract provided.


Symmetric Criticality In Classical Field Theory, Charles G. Torre, Ian M. Anderson Sep 2010

Symmetric Criticality In Classical Field Theory, Charles G. Torre, Ian M. Anderson

All Physics Faculty Publications

This is a brief overview of work done by Ian Anderson, Mark Fels, and myself on symmetry reduction of Lagrangians and Euler-Lagrange equations, a subject closely related to Palais’ Principle of Symmetric Criticality. After providing a little history, I describe necessary and sufficient conditions on a group action such that reduction of a group-invariant Lagrangian by the symmetry group yields the correct symmetry-reduced Euler-Lagrange equations.


Elementary And Middle School Science Lesson Plan: Solid, Liquid, Gas, What Is It?, Getaway Special Team 2010 Sep 2010

Elementary And Middle School Science Lesson Plan: Solid, Liquid, Gas, What Is It?, Getaway Special Team 2010

Education and Outreach

No abstract provided.


Polar Mesospheric Cloud Structures Observed From The Cloud Imaging And Particle Size Experiment On The Aeronomy Of Ice In The Mesosphere Spacecraft: Atmospheric Gravity Waves As Drivers For Longitudinal Variability In Polar Mesospheric Cloud Occurrence, A. Chandran, D. W. Rusch, A. W. Merkel, S. E. Palo, G. E. Thomas, Michael J. Taylor, S. M. Bailey, J. M. Russell Iii Jul 2010

Polar Mesospheric Cloud Structures Observed From The Cloud Imaging And Particle Size Experiment On The Aeronomy Of Ice In The Mesosphere Spacecraft: Atmospheric Gravity Waves As Drivers For Longitudinal Variability In Polar Mesospheric Cloud Occurrence, A. Chandran, D. W. Rusch, A. W. Merkel, S. E. Palo, G. E. Thomas, Michael J. Taylor, S. M. Bailey, J. M. Russell Iii

All Physics Faculty Publications

The cloud imaging and particle size (CIPS) experiment is one of three instruments on board the Aeronomy of Ice in the Mesosphere (AIM) spacecraft that was launched into a 600 km Sun‐synchronous orbit on 25 April 2007. CIPS images have shown distinct wave patterns and structures in polar mesospheric clouds (PMCs), around the summertime mesopause region, which are qualitatively similar to structures seen in noctilucent clouds (NLCs) from ground‐based photographs. The structures in PMC are generally considered to be manifestations of upward propagating atmospheric gravity waves (AGWs). Variability of AGW effects on PMC reported at several lidar sites ...


Electron-Induced Electron Yields Of Uncharged Insulating Materials, Ryan Carl Hoffmann May 2010

Electron-Induced Electron Yields Of Uncharged Insulating Materials, Ryan Carl Hoffmann

All Graduate Theses and Dissertations

Presented here are electron-induced electron yield measurements from high-resistivity, high-yield materials to support a model for the yield of uncharged insulators. These measurements are made using a low-fluence, pulsed electron beam and charge neutralization to minimize charge accumulation. They show charging induced changes in the total yield, as much as 75%, even for incident electron fluences of <3 fC/mm2, when compared to an uncharged yield. The evolution of the yield as charge accumulates in the material is described in terms of electron recapture, based on the extended Chung and Everhart model of the electron emission spectrum and the dual dynamic layer model for internal charge distribution. This model is used to explain charge-induced total yield modification measured in high-yield ceramics, and to provide a method for determining electron yield of uncharged, highly insulating, high-yield materials. A sequence of materials with progressively greater charge susceptibility is presented. This series starts with low-yield Kapton derivative called CP1, then considers a moderate-yield material, Kapton HN, and ends with a high-yield ceramic, polycrystalline aluminum oxide. Applicability of conductivity (both radiation induced conductivity (RIC) and dark current conductivity) to the yield is addressed. Relevance of these results to spacecraft charging is also discussed.


Investigating Characteristics Of Lightning-Induced Transient Luminous Events Over South America, Matthew A. Bailey May 2010

Investigating Characteristics Of Lightning-Induced Transient Luminous Events Over South America, Matthew A. Bailey

All Graduate Theses and Dissertations

Sprites, halos, and elves are members of a family of short-lived, luminous phenomena known as Transient Luminous Events (TLEs), which occur in the middle atmosphere. Sprites are vertical glows occurring at altitudes typically ranging from ~40 to 90 km. In video imagery they exhibit a red color at their top, with blue tendril-like structure at low altitudes. Elves are disk-like glows that occur at the base of the ionosphere, with diameters of ~100-300 km, and have very short lifetimes (~2-3 ms). Halos are diffuse glows that occur at low altitudes, have diameters <100 >km, and have a duration that may last ...


Hopping Conductivity And Charge Transport In Low Density Polyethylene, Jerilyn Brunson May 2010

Hopping Conductivity And Charge Transport In Low Density Polyethylene, Jerilyn Brunson

All Graduate Theses and Dissertations

The properties and behaviors of charge transport mechanisms in highly insulating polymers are investigated by measuring conduction currents through thin film samples of low density polyethylene (LDPE). Measurements were obtained using a constant voltage method with copper electrodes inside a chamber adapted for measurements under vacuum and over a wide range of temperatures and applied fields. Field-dependent behaviors, including Poole-Frenkel conduction, space charge limited current (SCLC), and Schottky charge injection, were investigated at constant temperature. These field-dependent mechanisms were found to predict incorrect values of the dielectric constant and the field dependence of conductivity in LDPE was not found to ...


Investigating Small-Scale Dynamical Features In The Mesopause Region, Deepak B. Simkhada May 2010

Investigating Small-Scale Dynamical Features In The Mesopause Region, Deepak B. Simkhada

All Graduate Theses and Dissertations

Utilizing analyses of observational data, we performed a detailed study to investigate short-period atmospheric gravity waves and ripples, and instabilities in the mesopause region. Recent coordinated measurements from Haleakala Observatory, Maui, HI via airglow wave imaging, meteor wind radar, and Na wind temperature lidar have provided a unique dataset for this study. Gravity waves generated in the lower atmosphere propagate energy upwards into the mesosphere and lower thermosphere region where they modulate the airglow emissions, and later break and deposit their momentum, causing significant perturbations in winds and temperatures. Ripples, on the other hand, are likely generated by localized shear ...


Classical Foundations For A Quantum Theory Of Time In A Two-Dimensional Spacetime, Nathan Thomas Carruth May 2010

Classical Foundations For A Quantum Theory Of Time In A Two-Dimensional Spacetime, Nathan Thomas Carruth

All Graduate Theses and Dissertations

We consider the set of all spacelike embeddings of the circle S1 into a spacetime R1 × S1 with a metric globally conformal to the Minkowski metric. We identify this set and the group of conformal isometries of this spacetime as quotients of semidirect products involving diffeomorphism groups and give a transitive action of the conformal group on the set of spacelike embeddings. We provide results showing that the group of conformal isometries is a topological group and that its action on the set of spacelike embeddings is continuous. Finally, we point out some directions for future research.


Evaluation Of Constant Voltage Chamber Modifications, Justin Dekany Apr 2010

Evaluation Of Constant Voltage Chamber Modifications, Justin Dekany

Senior Theses and Projects

Determining the electrical properties of highly insulating materials can be a challenging task. These materials are designed to greatly resist the flow of electrical current making them useful in the construction of spacecraft. Due to the fact that satellites are isolated from ground, charging caused by the plasma environment found in typical orbital radii (1) is of concern to the designers of modern spacecraft (2). The Utah State University Materials Physics Group Constant Voltage Chamber (CVC) has been designed to measure extremely low currents and low conductivity. Over the last five years, many changes have been made to improve the ...


On Theconsistency Of Model, Ground-Based And Satellite Observations Of Tidal Signatures: Initial Results From Thecawses Tidal Campaigns, W. E. Ward, J. Oberheide, L. P. Goncharenko, T. Nakamura, P. Hoffmann, W. Singer, L. C. Chang, J. Du, D. Y. Wang, P. Batista, B. Clemesha, A. H. Manson, D. M. Riggin, C. Y. She, T. Tsuda, Titus Yuan Apr 2010

On Theconsistency Of Model, Ground-Based And Satellite Observations Of Tidal Signatures: Initial Results From Thecawses Tidal Campaigns, W. E. Ward, J. Oberheide, L. P. Goncharenko, T. Nakamura, P. Hoffmann, W. Singer, L. C. Chang, J. Du, D. Y. Wang, P. Batista, B. Clemesha, A. H. Manson, D. M. Riggin, C. Y. She, T. Tsuda, Titus Yuan

All Physics Faculty Publications

Comparisons between tidal wind signatures diagnosed from satellite and ground-based observations and a general circulations model for two (September–October 2005, March–April 2007) of the four Climate and Weather of the Sun-Earth System (CAWSES) Global Tidal Campaign observation periods are presented (CAWSES is an international program sponsored by Scientific Committee on Solar-Terrestrial Physics). Specific comparisons are made between model (extended Canadian Middle Atmosphere Model), satellite (Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)), meteor, MF and incoherent scatter radar (ISR), and lidar tidal signatures in the mesosphere and lower thermosphere. The satellite and ground-based signatures are in good agreement and ...


Development Of Ultrasonic Detection Methods For Cancer Cells In Vivo, Jeffrey B. Goodrich Mar 2010

Development Of Ultrasonic Detection Methods For Cancer Cells In Vivo, Jeffrey B. Goodrich

Browse All Undergraduate research

A current problem in medicine and specifically breast cancer is the detection of microscopic cancer in surgical margins to ensure all of the cancer has been removed. Current methods rely on extensive pathology work that may take several days to complete. For breast cancer patients, positive findings for cancer in surgical margins require follow-up surgery to remove more tissue. Up to 50% of patients undergoing breast conservation surgery (lumpectomy) require additional surgery. A preferable method would be in vivo microscopic detection for use during surgery. Such methods would reduce risks, costs, and patient suffering that accompany follow-up operations. Ultrasound is ...


Funboe - Follow-Up Nucleate Boiling On-Flight Experiment: A Systematic Study Of Nucleate Boiling In Microgravity, Jt Farnsworth, Frank Mccown Mar 2010

Funboe - Follow-Up Nucleate Boiling On-Flight Experiment: A Systematic Study Of Nucleate Boiling In Microgravity, Jt Farnsworth, Frank Mccown

Posters

Utah State University’s Get Away Special (GAS) team was awarded the opportunity to participate in Reduced Gravity Student Flight Opportunities program administered by NASA. Six members of the GAS team will fly in a specialized jet which will simulate microgravity where the experiment can be performed in 30 second intervals. The purpose of the experiment is to determine the properties of nucleate boiling of water in weightlessness. The experiment will be monitored with temperature sensors, accelerometers, and high definition cameras and the results will be analyzed frame by frame. This will provide important information related to the dynamics of ...


Improved Methods For Teaching Science, Stephanie Peterson, Sara Scott Mar 2010

Improved Methods For Teaching Science, Stephanie Peterson, Sara Scott

Browse All Undergraduate research

Utah State University’s Get Away Special (GAS) team will conduct research aboard NASA's microgravity research aircraft, the “vomit comet,” through the Reduced Gravity Student Flight Opportunities program. Team members come from mechanical and aerospace engineering, computer science, physics, science education, and business backgrounds. The team will spend ten days this summer at NASA’s Johnson Space Center and perform experiments on the aircraft to better understand nucleate boiling, a potential method of efficient heat transfer in space.


Follow Up Nucleate Boiling On-Flight Experiment, Andrew Fassmann Mar 2010

Follow Up Nucleate Boiling On-Flight Experiment, Andrew Fassmann

Presentations

No abstract provided.


A Systemic Study Of Nucleate Boiling, Justin Koeln Mar 2010

A Systemic Study Of Nucleate Boiling, Justin Koeln

Posters

Nucleate boiling is a heavily researched form of heat transfer due to its associated high heat transfer rates. Applying two-phase heat transfer to space systems would allow these systems to become more capable, efficient, and compact. However, a fundamental understanding of boiling dynamics in the absence of buoyancy is yet to be developed. This study intends to analyze the effects of gravity, power input, and surface geometry during successive periods of microgravity provided by NASA’s “vomit comet” through the Reduced Gravity Student Flight Opportunities Program.


Simultaneous Separation And Detection Of Cations And Anions Ion A Microfluidic Device With Suppressed Electroosmotic Flow And A Single Injection Point, B. R. Reschke, J. Schiffbauer, Boyd F. Edwards, A. T. Timperman Mar 2010

Simultaneous Separation And Detection Of Cations And Anions Ion A Microfluidic Device With Suppressed Electroosmotic Flow And A Single Injection Point, B. R. Reschke, J. Schiffbauer, Boyd F. Edwards, A. T. Timperman

All Physics Faculty Publications

A rapid and simultaneous separation of cationic and anionic peptides and proteins in a glass microfluidic device that has been covalently modified with a neutral poly(ethylene glycol) (PEG) coating to minimize protein adsorption is presented. The features of the device allow samples that contain both anions and cations to be introduced from a central flow stream and separated in different channels with different outlets—all in the presence of low electroosmotic flow (EOF) imparted by the PEG coating. The analytes are electrophoretically extracted from a central hydrodynamic stream and electrophoretically separated in two different channels, in which pressure driven ...


Evaluation Of The Temperature And Time Dependence Of Electrostatic Breakdown, Charlie Sim Feb 2010

Evaluation Of The Temperature And Time Dependence Of Electrostatic Breakdown, Charlie Sim

Senior Theses and Projects

The goal of this research was to investigate temperature and time dependent models for the electrostatic breakdown of polymeric spacecraft insulators. Temperature dependent breakdown was found by inducing an electrostatic breakdown in the prototypical polymer Low Density Polyethylene (LDPE) at various temperatures. Time dependent breakdown was found by applying a static voltage to LDPE and measuring the time to electrostatic breakdown. No significant temperature dependence of the electrostatic breakdown of LDPE was observed in a temperature range of 150 K to 300 K. The time dependent results show that the time to electrostatic breakdown is modeled by a negative logarithmic ...


Equatorial Ionosphere Bottom-Type Spread-F Observed By Oi 630.0 Nm Airglow Imaging, H. Takahashi, M. A. Abdu, Michael J. Taylor, Pierre-Dominique Pautet, E. R. De Paula, E. A. Kherani, A. F. Medeiros, C. M. Wrasse, I. S. Batista, J. H.A. Sobral, D. Gobbi, D. Arruda, I. Paulino, S. Vadas, D. C. Fritts Feb 2010

Equatorial Ionosphere Bottom-Type Spread-F Observed By Oi 630.0 Nm Airglow Imaging, H. Takahashi, M. A. Abdu, Michael J. Taylor, Pierre-Dominique Pautet, E. R. De Paula, E. A. Kherani, A. F. Medeiros, C. M. Wrasse, I. S. Batista, J. H.A. Sobral, D. Gobbi, D. Arruda, I. Paulino, S. Vadas, D. C. Fritts

All Physics Faculty Publications

Bottom‐type spread F events were observed in the south American equatorial region by a VHF coherent radar and an ionosonde at São Luís (2.5°S, 44.3°W), an ionosonde at Fortaleza (3.9°S, 38.4° W) and an airglow OI 630.0 nm imager at Cariri (7.4°S, 36.5°W) and Brasilia (14.8°S, 47.6°W). In the evening of September 30, 2005, a long duration (∼70 minutes) bottom side scattering layer, confined in a narrow height region, was observed. At the same time all‐sky imager observed sinusoidal intensity depletions in ...


Constraining The Black Hole Mass Spectrum With Gravitational Wave Observations – I. The Error Kernel, Danny C. Jacobs, Joseph E. Plowman, Ronald W. Hellings, Sachiko Tsuruta, Shane L. Larson Feb 2010

Constraining The Black Hole Mass Spectrum With Gravitational Wave Observations – I. The Error Kernel, Danny C. Jacobs, Joseph E. Plowman, Ronald W. Hellings, Sachiko Tsuruta, Shane L. Larson

All Physics Faculty Publications

Many scenarios have been proposed for the origin of the supermassive black holes (SMBHs) that are found in the centres of most galaxies. Many of these formation scenarios predict a high-redshift population of intermediate-mass black holes (IMBHs), with masses M in the range 102M≲ 105 M. A powerful way to observe these IMBHs is via gravitational waves the black holes emit as they merge. The statistics of the observed black hole population should, in principle, allow us to discriminate between competing astrophysical scenarios for the origin and formation of SMBHs. However, gravitational wave detectors such as Laser ...