Physical Sciences and Mathematics Commons^™

Fabrication And Performance Of A Microfluidic Traveling-Wave Electrophoresis System, K. D. Jo, J. E. Schiffbauer, Boyd F. Edwards, R. Lloyd Carroll, A. T. Timperman

All Physics Faculty Publications

A microfluidic traveling-wave electrophoresis (TWE) system is reported that uses a locally defined traveling electric field wave within a microfluidic channel to achieve band transport and separation. Low voltages, over a range of-0.5 to +0.5 V, are used to avoid electrolysis and other detrimental redox reactions while the short distance between electrodes, ∼25 μm, provides high electric fields of ∼200 V cm ^-1. It is expected that the low voltage requirements will simplify the future development of smaller portable devices. The TWE device uses four interdigitated electrode arrays: one interdigitated electrode array pair is on the top of the …

Charge Enhanced Contamination And Environmental Degradation Of Misse-6 Suspecs Materials, John R. Dennison, Amberly Evans, Danielle Fulmer, Joshua L. Hodges

All Physics Faculty Publications

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 have been investigated by comparing pre- and post-flight characterization measurements. The State of Utah Space Environment and 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), and was retrieved in September 2009. A total of 165 samples were mounted on three separate SUSpECS panels on the ram and wake sides on the …

Juggling By Numbers: Siteswap Notation For Juggling, David Tate

Browse All Undergraduate research

A basic overview of the juggling notation known as "Siteswap". This is a way of describing juggling patterns using sequences of numbers.

Measurement Methods Of Electron Emission Over A Full Range Of Sample Charging, R. Hoffmann, John R. Dennison

All Physics Faculty Publications

Spacecraft charging codes require accurate models of electron yields as a function of accumulated charge to correctly predict the charge build up on spacecraft. The accumulated charge creates equilibrium surface potentials on spacecraft resulting from interactions with the space plasma environment. There is, however, a complex relation between these emission properties and the charge built up in spacecraft insulators.

This paper focuses on different methods appropriate to determine the fundamental electronic material property of total electron yield as the materials accumulate charge. Three methods for determining the uncharged total yield are presented:

(i) The DC Continuous Beam Method is a …

The Effects Of Surface Modification On Spacecraft Charging Parameters, Amberly Evans Jensen, Jr Dennison

Graduate Student Publications

Charging of materials by incident radiation is affected by both environmental and physical conditions. Modifying a material’s physical surface will change its reflection, transmission and absorption of the incident radiation which are integrally related to the accumulation of charge and energy deposition in the material. General arguments for incident and emitted photons, electrons and ions are considered. An optical analysis of the effects of surface modification on spacecraft charging parameters on prototypical polyimide Kapton HNTM and Cu samples is presented. Samples were roughened with abrasive compounds ranging from 0.5 to 10 μm in size, comparable to the range of incident …

Two New Species Of Trigonotylus (Hemiptera: Heteroptera: Miridae: Stenodemini) From Western Canada And Northwestern United States, G G.E. Scudder, Michael D. Schwartz

Green Canyon Environmental Research Area, Logan Utah

No abstract provided.

The Effect Of Space Environment On Wireless Communication Devices' Performance, Landon Hillyard, Jr Dennison, Jan J. Sojka

Presentations

No abstract provided.

New Symbolic Tools For Differential Geometry, Gravitation, And Field Theory, Ian Anderson, Charles Torre

Presentations and Publications

DifferentialGeometry is a Maple software package which symbolically performs fun- damental operations of calculus on manifolds, differential geometry, tensor calculus, spinor calculus, Lie algebras, Lie groups, transformation groups, jet spaces, and the variational calculus. These capabilities, combined with dramatic recent improve- ments in symbolic approaches to solving algebraic and differential equations, have allowed for development of powerful new tools for solving research problems in gravitation and field theory. The purpose of this paper is to describe some of these new tools and present some advanced applications involving: Killing vector fields and isometry groups, Killing tensors, algebraic classification of solutions of …

The Dynamic Interplay Between Spacecraft Charging, Space Environment Interactions And Evolving Materials, John R. Dennison

All Physics Faculty Publications

The charge on spacecraft is constantly changing, as a result of the dynamic nature of the space environment, the spacecraft orbit, the interactions between environment and spacecraft, and even the spacecraft materials. While the effects on spacecraft charging from varying environmental conditions and from the selection of different construction materials have been studied extensively, the modification of material properties by the space plasma environment can also have profound effects on spacecraft charging. These same considerations apply to other extreme plasma applications. This presentation focuses on the measurement methods and modeling we use to study electron emission and transport processes, charging, …

Investigating Mountain Waves In Mtm Image Data At Cerro Pachon, Chile, Neal R. Criddle, M. J. Taylor, P.-D. Pautet, Y. Zhao, G. Swenson, A. Liu

Neal R Criddle

Gravity waves are important drivers of chemical species mixing, energy and momentum transfer into the MLT (~80 - 100 km) region. As part of a collaborative program involving instruments from several institutions Utah State University has operated a Mesospheric Temperature Mapper (MTM) at the new Andes Lidar Observatory (ALO) on Cerro Pachon (30.2°S, 70.7°W) Since August 2009. A primary goal of this program is to quantify the impact of mountain waves on the MLT region. The Andes region is an excellent natural laboratory for investigating gravity wave influences on the MLT region, especially the study of mountain waves, created by …

Automatic Geomorphic Feature Extraction From Lidar In Flat And Engineered Landscapes, Paola Passalacqua, Patrick Belmont, Efi Foufoula-Georgiou

Watershed Sciences Faculty Publications

High-resolution topographic data derived from light detection and ranging (lidar) technology enables detailed geomorphic observations to be made on spatially extensive areas in a way that was previously not possible. Availability of this data provides new opportunities to study the spatial organization of landscapes and channel network features, increase the accuracy of environmental transport models, and inform decisions for targeting conservation practices. However, with the opportunity of increased resolution topographic data come formidable challenges in terms of automatic geomorphic feature extraction, analysis, and interpretation. Low-relief landscapes are particularly challenging because topographic gradients are low, and in many places both the …

Nitrogen Partitioning And Transport Through A Subalpine Lake Measured With An Isotope Tracer, Dave M. Epstein, Wayne A. Wurtsbaugh, Michelle A. Baker

Watershed Sciences Faculty Publications

We used a stable isotope tracer to measure nitrogen (N) assimilation and transfer through Bull Trout Lake, a 0.3-km2 mountain lake in Idaho, specifically to explore the relative importance of pelagic and benthic producers. was added into the inflow stream above the lake during spring runoff and the resulting mass of tracer was measured within the various ecosystem compartments, including the outflow stream. Although a portion of the moved through the lake quickly due to a low hydraulic residence time during the addition, the tracer was also assimilated rapidly by seston in the water column and at a slower rate …

An Embedded-Atom-Method Model For Alkali-Metal Vibrations, R. B. Wilson, D. Mark Riffe

All Physics Faculty Publications

We present an embedded-atom-method (EAM) model that accurately describes the vibrational dynamics in the alkali metals Li, Na, K, Rb and Cs. The bulk dispersion curves, frequency-moment Debye temperatures and temperature-dependent entropy Debye temperatures are all in excellent agreement with experimental results. The model is also well suited for studying surface vibrational dynamics in these materials, as illustrated by calculations for the Na(110) surface.

Short-Period Gravity Waves Over Alaska, Michael Negale, Kim Nielsen, Michael J. Taylor, Britta Irving, Richard Collins

Physics Student Research

The propagation nature and sources of short-period gravity waves have been studied extensively at low and mid-latitudes, while their extent and nature at the polar regions are less known. During the last decade, observations from select sites on the Antarctic continent have revealed a significant presence of these waves over the southern Polar Region as well as shown unexpected dynamical behavior. In contrast, observations over the Arctic region are few and the dynamical behavior is unknown. A recent project was initiated in January 2011 to investigate the presence and dynamics of these waves over interior Alaska. This site provides an …

In Situ Surface Voltage Measurements Of Dielectrics Under Electron Beam Irradiation, Joshua L. Hodges, John R. Dennison, Justin Dekany, Gregory Wilson, Amberly Evans, Alec Sim

All Physics Faculty Publications

New instrumentation has been developed for non-contact, in vacuo measurements of the electron beam-induced surface voltage as a function of time and position for non-conductive spacecraft materials in a simulated space environment. Used in conjunction with the capabilities of an existing ultrahigh vacuum electron emission analysis chamber, the new instrumentation facilitates measurements of charge accumulation, bulk resistivity, effects of charge depletion and accumulation on yield measurements, electron induced electrostatic breakdown potentials, radiation induced conductivity effects, and the radial dispersion of surface voltage. The novel system uses two movable capacitive sensor electrodes that can be swept across the sample to measure …

A Systematic Construction Of Curved Phase Space: A Gravitational Gauge Theory With Symplectic Form, Jeffrey S. Hazboun, James Thomas Wheeler

All Physics Faculty Publications

General relativity can be constructed as a gauge theory using the quotient manifold strategy of [1, 2]. We consider a conformal gauging where the geometry is far richer than normal spacetime, including a symplectic form and the necessary emergence of Lorentzian signature. The resulting 2n-dim manifold constitutes a relativistic phase space, and general relativity is recovered when we demand that the momentum space is flat. However, the full geometry allows for curved phase space.

Kings Canyon To Alger Pass Pipeline Project, Project No. Utu-82322, United States Department Of The Interior, Bureau Of Land Management

Environmental Assessments (UT)

XTO has requested their existing Temporary Use Permit (UTU-82322-01), which authorizes an existing 8 inch, surface, steel, and natural gas pipeline be converted to a permanent right-of-way grant. In addition, XTO proposes to remove a portion of the existing pipeline and to install an additional 15,075 feet of 12 inch, buried, natural gas pipe line to re-direct the flow of gas. XTO has constructed a natural gas compressor plant (Wild Horse Bench Compressor Site) on Ute Tribal land and would like to redirect the flow of gas from the Kings Canyon Area to this facility which involves the removal of …

Investigating Forest Inventory And Analysis-Collected Tree-Ring Data From Utah As A Proxy For Historical Climate, R. Justin Derose, Shih-Yu (Simon) Wang, John D. Shaw

Wasatch Dendroclimatology Research

Increment cores collected as part of the periodic inventory in the Intermountain West were examined for their potential to represent growth and be a proxy for climate (precipitation) over a large region (Utah). Standardized and crossdated time-series created from pinyon pine (n=249) and Douglas-fir (n=274) increment cores displayed spatiotemporal patterns in growth differences both between species and by region within Utah. However, the between-species interrelationship of growth was strong over much of the state and indicated both species respond similarly to climate variations. Indeed, pinyon pine and Douglas-fir exhibited a significant and spatially coherent response to instrumental precipitation data. Previous …

High Intensity Land Treatment (Hilt) Practices, John P. Martin, Ronald C. Sims

Reports

Land treatment is categorized in the Resource Conservation and Recovery Act of 1976 (RCRA) as one of the land disposal options for managing hazardous waste constituents within the defined treatment zone before such constituents can be transported to surface water, groundwater, or air. Under the authroity of Subtitle C of RCFA, the U.S. Environmental Protection Agency has promulgated regulations governing the treatment and disposal of hazardous wastes in land treatment units (40 CFR, Part 264, Subpart M, July 26, 1982). The objectives of this report were to identify land treatment facilities meeting the defined high intensity land treatment (HILT) criteria, …

Solving Problems In Water Quality, Utah Water Research Laboratory

Reports

No abstract provided.

On The Nature Of Short-Period Mesospheric Gravity Wave Propagation Over Halley, Antarctica, K. Nielsen, Michael J. Taylor, R. E. Hibbins, M. J. Jarvis, J. M. Russell

All Physics Faculty Publications

As part of a collaborative program between British Antarctic Survey and Utah State University, measurements were made using an all-sky airglow imager located at the U.K. Halley Station (76°S, 27°W) during the 2000 and 2001 austral winter seasons from April through to early September. A co-located imaging Doppler interferometer was utilized to obtain coincident wind measurements for a total of 171 wave events. This study comprises the first detailed climatological investigation of the propagation nature (freely propagating, Doppler ducted, or evanescent) of individual quasi-monochromatic, short-period wave events at a high southern latitude. Distributions of the derived vertical wavelength exhibit an …

Small Scale Simulation Chamber For Space Environment Survivability Testing, Robert H. Johnson, Lisa D. Montierth, John R. Dennison, James S. Dyer, Ethan Lindstrom, Alex Chanson

All Physics Faculty Publications

A versatile vacuum system for long duration testing of materials modifications due to exposure to simulated space environment conditions has been designed and built. The chamber is particularly well suited for cost-effective tests of multiple small scale materials samples over prolonged exposure. Critical environmental components simulated include neutral gas [ultrahigh vacuum (10-7 Pa) to ambient], FUV/UV/VIS/NIR solar spectrum, electron plasma fluxes, and temperature. The UV/VIS/NIR solar spectrum is simulated using an external, normally incidence and collimated class AAA Solar Simulator source, with standard Air Mass Zero (AM0) filters to shape the incident radiation spectrum. This Xe arc discharge tube source …

Electron Energy Dependent Charging Effects Of Multilayered Dielectric Materials, Gregory Wilson, John R. Dennison, Amberly Evans, Justin Dekany

All Physics Faculty Publications

Measurements of the charge distribution in electron-bombarded, thin-film, multilayer dielectric samples showed that charging of multilayered materials evolves with time and is highly dependent on incident energy; this is driven by electron penetration depth, electron emission and material conductivity. Based on the net surface potential’s dependence on beam current, electron range, electron emission and conductivity, measurements of the surface potential, displacement current and beam energy allow the charge distribution to be inferred. To take these measurements, a thin-film disordered SiO2 structure with a conductive middle layer was charged using 200 eV and 5 keV electron beams with regular 15 s …

Electron Transport Models And Precision Measurements In A Constant Voltage Chamber, Justin Dekany, Alec Sim, Jerilyn Brunson, John R. Dennison

All Physics Faculty Publications

The conductivity of the material is a key transport parameter in spacecraft charging that determines how deposited charge will redistribute throughout the system, how rapidly charge imbalances will dissipate, and what equilibrium potential will be established under given environmental conditions. As the requirements for space missions extend to new regions of space and more stringent requirements are placed on spacecraft performance, it becomes necessary to better understand the underlying conduction mechanisms that determine the dynamic response of insulators to temperature, electric field dose rate, and sample conditioning and history. This study performed detailed measurements of the transient conductivity of representative …

Ultrahigh Vacuum Cryostat System For Extended Low Temperature Space Environment Testing, Justin Dekany, Robert H. Johnson, Gregory Wilson, Amberly Evans, John R. Dennison

All Physics Faculty Publications

The range of temperature measurements have been significantly extended for an existing space environment simulation test chamber used in the study of electron emission, sample charging and discharge, electrostatic discharge and arcing, electron transport, and luminescence of spacecraft materials. This was accomplished by incorporating a new twostage, closed-cycle helium cryostat which has an extended sample temperature range from 40 K to 450 K, with long-term controlled stability of 0.5 K. The system was designed to maintain compatibility with an existing ultrahigh vacuum chamber (base pressure 10-7 Pa) that can simulate diverse space environments. These existing capabilities include controllable vacuum and …

Hydrologic Efficiency In Water Conservation, L. Douglas James

Reports

Introduction: The hydrologic cycle can be subdivided into three phases: 1)Humidity is transported within the atmosphere and becomes precipitation, and 2) Water moves downhill until eventually reaching the sea while all the time 3) Evapotranspiration returns exposed moisture to the atmosphere. During its movement, flowing water transports suspended sediments and dissolved minerals to reshape landforms and redistribute the mineral composition of the earth's surface throughout geologic time. It is during the second phase that flowing water can be diverted for uses that generally add to evaportranspiration (through consumptive use) and transport (through waste disposal). The water resources development that serves …

Information For Operation Of Water Supply Systems, L. Douglas James, Glen E. Stringham, J. Clair Batty

Reports

Introduction: Water requirements increase as more people use more water for domestic purposes. The increase is augmented as technological advances add to the water needs of agriculture and industry. Additional urban landscaping adds further to the demand. Simultaneously, the same forces increase demands for flood control, hydrelectric power, and navigation; and a more urbanized population want more flows preserved for productive natural environments, recreational use, and aesthetic enjoyment. The response over the years to these growing demands on water resources has been to supply increasing amounts of water and greater levels of development for other purposes by building more projects, …

Cee & Uwrl Research In Action, Utah Water Research Laboratory

Reports

Introduction: The Department of Civil and Environmental Engineer (CEE) and the Utah Water Research Laboratory (UWRL) have a symbiotic working relationship. The CEE Department provides the pricipal investigators with academic affiliation to the university while the UWRL provides faculty with a strong water research arena. Both the CEE department and the UWRL have been involved in research and problem solving for government agencies and private industry.

The Second Annual Space Weather Community Operations Workshop: Advancing Operations Into The Next Decade, Jennifer L. Meehan, Jared Fulgham, W. Kent Tobiska

Graduate Student Publications

No abstract provided.

Workshop Addresses Aviation Community, Jennifer L. Meehan, Joseph Kunches

Graduate Student Publications

No abstract provided.