Physical Sciences and Mathematics Commons^™

Data From: Anomalous Electron Temperature, Bela G. Fejer

Browse all Datasets

Anomalous Electron Temperatures in the evening equatorial ionosphere. These are outputs of simulations from the semi-empirical SAMI2-PE (Varney et al. 2012) for the night of the 02 and 05 August 2011.

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes, Melissa S. Chapot, Alexis K. Ault, Greg Hirth, Robert G. Mcdermott

Geosciences Faculty Publications

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick …

Modeling Lake Temperature Response To Climate Change In The Alaskan Arctic, Thomas Balkcom

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

This thesis study focuses on simulating lake temperature and ice duration for four lakes at the Arctic Long-Term Ecological Research site, near the Toolik Field Station in Alaska. Model projections were driven by the representative global climate model outputs under different carbon emission scenarios. Results show that my simple lake model can reproduce historical lake temperature and ice duration observations, indicating the reliability of the model for future projections. Model projections show that JuneSeptember lake temperatures would increase by 4.3-5.8 °C from the historical period with most progressive carbon emission scenarios, but by 0.7-2.2 °C in the conservative scenarios. Results …

Nanoscale Evidence For Temperature-Induced Transient Rheology And Postseismic Fault Healing, Alexis K. Ault, Jordan L. Jensen, Robert G. Mcdermott, F.-A. Shen, B. R. Van Devener

Geosciences Faculty Publications

Friction-generated heat and the subsequent thermal evolution control fault material properties and thus strength during the earthquake cycle. We document evidence for transient, nanoscale fault rheology on a high-gloss, light-reflective hematite fault mirror (FM). The FM cuts specularite with minor quartz from the Pleistocene El Laco Fe-ore deposit, northern Chile. Scanning and transmission electron microscopy data reveal that the FM volume comprises a2+ suboxides. Sub–5-nm-thick silica films encase hematite grains and connect to amorphous interstitial silica. Observations imply that coseismic shear heating (temperature >1000 °C) generated transiently amorphous, intermixed but immiscible, and rheologically weak Fe-oxide and silica. Hematite regrowth in …

The Long‐Term Trends Of Nocturnal Mesopause Temperature And Altitude Revealed By Na Lidar Observations Between 1990 And 2018 At Midlatitude, Tao Yuan, Stanley C. Solomon, Chiao -Y. She, D. A. Krueger, Han-Li Liu

All Physics Faculty Publications

The mesopause, a boundary between mesosphere and thermosphere with the coldest atmospheric temperature, is formed mainly by the combining effects of radiative cooling of CO2, and the vertical adiabatic flow in the upper atmosphere. A continuous multidecade (1990‐2018) nocturnal temperature data base of an advanced Na lidar, obtained at Fort Collins, CO (41°N, 105°W), and at Logan, UT (42°N, 112°W), provides an unprecedented opportunity to study the long‐term variations of this important atmospheric boundary. In this study, we categorize the lidar‐observed mesopause into two categories: the “high mesopause” (HM) above 97 km during nonsummer months, mainly formed through the radiative …

Juxtaposition At 45 Km Of Temperatures From Rayleigh-Scatter Lidar And Reanalysis Models, David K. Moser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Weather and climate forecasts are almost exclusively produced by computer models, which use atmospheric measurements as starting points. It is a well-known and joked-about fact that model predictions can be incorrect at times. One of the reasons this happens is due to gaps in our knowledge of atmospheric conditions in areas where measurements don’t often taken place, such as the mesosphere, which stretches from roughly 45-90 km altitude.

A lidar is a device that can shoot out short bursts of laser light to measure things such as atmospheric thickness at a distance. From this information one can then derive the …

Examination Of The Climate Factors That Reduced Wheat Yield In Northwest India During The 2000s, Avik Mukherjee, Shih-Yu (Simon) Wang, Parichart Promchote

Plants, Soils, and Climate Faculty Publications

In India, a significant reduction of wheat yield would cause a widespread impact on food security for 1.35 billion people. The two highest wheat producing states, Punjab and Haryana in northern India, experienced a prolonged period of anomalously low wheat yield during 2002–2010. The extent of climate variability and change in influencing this prolonged reduction in wheat yield was examined. Daily air temperature (T_max and T_ave) was used to calculate the number of days above optimum temperature and growing degree days (GDD) anomaly. Two drought indices, the standard precipitation and evapotranspiration index and the radiation-based precipitation index, …

Sodium Lidar For Mesopause Temperature And Wind Studies, Xiaoqi Xi

Physics Capstone Projects

In 1990 Dr. Chiao-Yao She developed a narrowband Na Temperature lidar in Colorado State University (CSU), it immediately became an important instrument to measure the temperature in mesopause region (80-105 km in altitude): the atmospheric layer between mesosphere and thermosphere [Krueger et al., 2015]. Led by Dr. Tao Yuan, this system was relocated to Utah State University (USU) in summer 2010 and has been continuing its exploration of upper atmosphere. This report will give a brief introduction to the theory and application of Sodium Lidar.

Long-Term Midlatitude Mesopause Region Temperature Trend Deduced From Quarter Century (1990-2014) Na Lidar Observations, Chiao Y. She, D. A. Krueger, Tao Yuan

All Physics Faculty Publications

The long-term midlatitude temperature trend between 85 and 105 km is deduced from 25 years (March 1990-December 2014) of Na Lidar observations. With a strong warming episode in the 1990s, the time series was least-square fitted to an 11-parameter nonlinear function. This yields a cooling trend starting from an insignificant value of 0.64 ± 0.99 K decade^-1 at 85 km, increasing to a maximum of 2.8 ± 0.58K decade^-1 between 91 and 93 km, and then decreasing to a warming trend above 103 km. The geographic altitude dependence of the trend is in general agreement with model predictions. …

Diffusive Electron Heat Flow And Temperature Variance Along Magnetic Field Lines, Michael Kushlan

Physics Capstone Projects

In this research we examine how electron heat moves along magnetic field lines and how this affects temperature variations in plasmas. Specifically we wrote FORTRAN code to solve the electron temperature equation numerically. We also solved the steady state electron temperature equation analytically using an integrating factor. We verified that the numerical and analytical solutions obtained the same result. Finally we calculated the standard deviation of temperature in our domain for the steady state. Gaussian legendre quadrature was used to integrate various functions. We represented our magnetic field and heat source with Fourier series. The sin and cosine coefficients for …

Forward Model For Temperature Derivation From Atmospheric Lidar, Jaren Hobbs

Physics Capstone Projects

Atmospheric Lidar takes advantage of Rayleigh backscattering to create a relative density profile of the atmosphere. The method for temperature derivation is based on the work of Chanin and Hauchecorne (CH). Beginning with an initial temperature, and utilizing the ideal gas law, a downward integration procedure is applied to create a temperature profile from the density profile down to forty- five kilometers. Since this initial temperature is only a best guess, the temperatures towards the top of the profile may not be accurate. However, so long as the guess is reasonable, within perhaps a fifty Kelvin margin (though hopefully not …

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 …

Assessing Linkages Among Landscape Characteristics, Stream Habitat, And Macroinvertebrate Communities In The Idaho Batholith Ecoregion, Andrew C. Hill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the composition of lotic communities and the landscape processes and habitat characteristics that shape them is one of the main challenges confronting stream ecologists. In order to better understand the linkages among landscape processes, stream habitat, and biological communities and to understand how accurately our measurements represent important factors influencing biological communities, it is important to test explicit hypotheses regarding these linkages. Increasing our understanding of aquatic communities in a hierarchical context and recognizing how well our measurements represent factors structuring aquatic communities will help managers better evaluate the influence of land management practices on aquatic ecosystems, direct conservation …

Engineering Tool For Temperature, Electric Field And Dose Rate Dependence Of High Resistivity Spacecraft Materials, John R. Dennison, Alec Sim, Jerilyn Brunson, Steven Hart, Jodie Gillespie, Justin Dekany, Charles Sim, Dan Arnfield

All Physics Faculty Publications

An engineering tool has been developed to predict the equilibrium conductivity of common spacecraft insulating materials as a function of electric field, temperature, and adsorbed dose rate based on parameterized, analytic functions derived from physics-based theories. The USU Resistivity Calculator Engineering Tool calculates the total conductivity as the sum of three independent conductivity mechanisms: a thermally activated hopping conductivity, a variable range hopping conductivity, and a radiation induced conductivity using a total of nine independent fitting parameters determined from fits to an extensive data set taken by the Utah State University Materials Physics Group. It also provides a fit for …

Landscape Patterns Of Streams & Lakes In Montane Watersheds Determine Water Temperatures & Nutrient Transport: Watershed Analyses And N Tracer Experiments, Wayne A. Wurtsbaugh, J. Garrett, G. Burkart, W. Fleenor, K. Nydick, R. Hall, Michelle A. Baker

Watershed Sciences Faculty Publications

In glaciated mountains, lakes are interspersed through watersheds and connected by streams. Although lakes or streams are frequently studied as individual water bodies, studying them as integrated functional units provides considerable insight on temperature patterns, nutrient transport and other functions. In the Sawtooth Mountains (Idaho), inter-lake distance averages 2.8 km. In summer, lakes are solar collectors, and warm outflow streams as much as 10 C, thus increasing metabolic rates. These streams seldom cool to equilibrium temperatures before encountering another lake, where the waters tend to overflow and mix into the epilimnion. With overflow, N-15 tracer experiments demonstrated that water and …

Mesospheric Temperature Climatology Above Utah State University, Joshua P. Herron

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Rayleigh-scatter lidar has been in operation at Utah State University (41. 7° N, 111.8 ° W) starting in September 1993 until the present (October 2003). The return profiles from the atmosphere have been analyzed to provide temperature measurements of the middle atmosphere from 45 to 90 km. Various methods of averaging were used to construct a temperature climatology of the region based on these observations. The data analysis algorithm has been critically analyzed to find possible sources of error, and has been compared to an independently derived technique. The resulting temperatures have been compared to other mid-latitude lidars with …

Low Temperature Silicon Epitaxy On Hydrogen Terminated Si(100) Surfaces, J. -Y. Ji, T. -C. Shen

T. -C. Shen

Si deposition on H terminated Si(001)-2×1 surfaces at temperatures 300–530K is studied by scanning tunneling microscopy. Hydrogen apparently hinders Si adatom diffusion and enhances surface roughening. The post-growth annealing effect is analyzed. Hydrogen is shown to remain on the growth front up to at least 10ML. Si deposition onto the H/Si(001)-3×1 surface at 530K suggests that dihydride units further suppress Si adatom diffusion and increase surface roughness.

What Limits Tailed Frog Tadpole Density And Distribution In Western Montana Streams?, Megan Barker

Undergraduate Honors Capstone Projects

We explored the possible limitation of temperature and other habitat features on tailed frog tadpole populations in northwestern Montana. We sampled densities and habitat features in two regions with different climatic regimes and in streams with and without tadpoles, expecting larger density and size in the warmer region. We also expected habitat conditons to be more optimal (higher gradient, swifter velocity, and less canopy cover) in streams with tadpoles. Temperature appeared to positively influence tadpole size, though both tadpole size and density were strongly correlated with other variables. Density was correlated with gradient, canopy, depth, and elevation, whereas length was …

Habitat Selection By Lacustrine Rainbow Trout Within Gradients Of Temperature, Oxygen, And Food Availability, Chris Luecke, D. Teuscher

Watershed Sciences Faculty Publications

Rainbow trout (Oncorhynchus mykiss [Walbaum]) in Castle Lake, California were concentrated at certain depths during day and evening hours. A fish bioenergetics simulation model based on vertical gradients of temperature, oxygen concentration, and food availability indicated that rainbow trout selected habitats that maximized growth rate. In 1 of the 2 years of study, a strong pattern of diel vertical migration of rainbow trout was evident and was associated with vertical migrations of daphnids in the lake. The simulation model correctly predicted the occurrence and magnitude of fish migration. During the day some trout resided at depths with little potential for …

An Empirical Model Of Gastric Evacuation Rates For Fish And An Analysis Of Digestion In Piscivorous Brown Trout, E. He, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

The gastric evacuation rates of brown trout Salmo trutta (0.9–1.6 kg) feeding on fingerling rainbow trout Oncorhynchus mykiss (3.5–7.6 g) were measured in the laboratory at five temperatures (4.5, 9.0, 14.0, 19.0, and 22.5°C). Instantaneous gut evacuation rates (Re) increased exponentially with temperature (T): Re = 0.053se^0.073T, r^2 = 0.98; they varyied from 7%sh^–1 at 4.5°C to 29%sh^–1 at 22.5°C. Linear regressions described the relationship between time and qualitative measures of fish digestion, thus allowing investigators to determine how long an ingested fish would be identifiable at different temperatures. An analysis of published evacuation rates (N = 121) of 22 …

Extension Of The Metal Light Pipe Infrared Spectroscopy Technique: Applications To Surface Adsorption And High Tc Superconductors, Torsten Will

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The development of an infrared instrument for the study of surface adsorption and high T_c superconductors is presented and its applicability is discussed. The use of and theoretical background for the metal light pipe multiple-reflection technique are discussed in comparison to other infrared devices. Measurements are carried out to determine its limitations with powdered substrates as well as its sensitivity limitation for thin films. The results of the two test measurements, adsorption of CO on MgO and investigation of the energy gap of high T_c superconductors, are presented. Comparisons of the spectra with the experimental and theoretical literature …

Overstory Removal And Residue Treatments Affect Soil Surface, Air, And Soil Temperature: Implications For Seedling Survival, United States Department Of Agriculture, Forest Service

Forestry

Timber harvesting and residue reduction practices that alter shade, surface thermal properties, and moisture influence energy balance and heat transfer on the site, significantly influencing temperatures. Because the problems of mortality to seedlings due to high temperature and insufficient moisture are potentially widespread and expensive, it is crucial to be able to identify problem sites during the planning process.

Soil Water And Temperature In Harvested And Nonharvested Pinyon-Juniper Stands, United States Department Of Agriculture, Forest Service

Forestry

Tree harvesting increased soil water content, but the effect diminished over 4 years. The mean increase in soil water content was 2 to 4 percent the first year following harvest and 0 to 3 percent after 4 years. Although tree harvesting released soil water previously used by tree species, other biotic and abiotic demands increased. We speculate postharvest increases in wind and solar energy at the ground surface and increased understory transpiration in part explain the decline in soil water content differences between harvested and nonharvested plots over time.

Growth And Activity Of Juvenile Mosquitofish: Temperature And Ration Effects, Wayne A. Wurtsbaugh, J. Cech

Watershed Sciences Faculty Publications

The effects of constant temperatures (10, 15, 20, 25, 30, and 35 C) and ration size on the growth rates and activity of juvenile mosquitofish Gambusia affinis (mean wet weight, about 20 mg) were measured in laboratory experiments. On ad libitum rations of Tubifex spp. worms, food-consumption rates of mosquitofish were very high, ranging from 7% dry body weight/day at 10 C to 83%/day at 35 C. Growth increased from 0% dry body weight/day at 10 C to 21%/day at 30 C and declined slightly at 35 C. Gross efficiencies (100 growth/food consumption) increased from 0 at 10 C to …

Geology, Characteristics, And Resource Potential Of The Low Temperature Geothermal System Near Midway, Wasatch County, Utah, James F. Kohler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent awareness of the finite nature of fossil-fuel resources has resulted in an increased interest in alternate sources of energy such as geothermal. To evaluate the geothermal energy potential of the hot-springs system near Midway, Wasatch Co., Utah, consideration was given to heat flow, water chemistry, and structural controls.

Abnormal heat flow was indicated qualitatively by snow-melt patterns and quantitatively by heat-flow measurements that were obtained from two of four temperature-gradient wells drilled in the area. These measurements indicated that the area north of the town of Midway is characterized by heat flow equal to 321.75 mW/m², which …

Radar Measurements Of Neutral Winds And Temperatures In The Equatorial E Region, B. B. Balsley, Bela G. Fejer, D. T. Farley, R. F. Woodman

Bela G. Fejer

The phase velocity of type 1 irregularities in the equatorial electrojet, which can be easily measured by radar, depends upon both the ion acoustic velocity (and hence the temperature) in the medium and the neutral wind velocity. By measuring the phase velocity at several zenith angles both of these quantities in principle can be determined. This note describes the technique and its limitations and presents a few preliminary results obtained at 50 MHz at the Jicamarca Radar Observatory in Peru. These results show E region east-west wind velocities as large as 100 m/s, temperature variations of greater than 100°K, and …

Estimation Of Pan Evaporation From Climatological Data, Jerald Emmet Christiansen, Ashwin D. Mehta

Reports

A new formula and coefficients for climatological factors was developed for estimating pan evaporation based on an analysis of data from 23 states in the U. S. and from five other countries. This formula may be written: Ev=K R Ct Cw Ch Cs Ce Cm in which K is a dimensionless constant R is the theoretical radiation reaching the outer atmosphere, expressed as equivalent evaporation in the same units~ , as Ev. Ct, Cw, Ch,and Cs are dimensionless sub-coefficients for temperature , wind, humidity, and sunshine. Ce is a sub-coefficient for elevation, and Cm is a monthly coefficient Equations were …

Temperature Dependence Of Soil-Moisture Potential, Jacob Willem Kijne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Teachers have noticed that children draw only those objects which they know by name. Doubtless the adult has a similar tendency, exemplified by the researcher, to limit his observations or to relate them to that which can be expressed in the terminology of an existing or newly developed theory. In this thesis the data obtained from studies of the temperature and pressure dependence of the relative vapor pressure over moist soil samples are analyzed by a thermodynamic approach. Not all of the results can be explained completely by means of this tool. Natural systems, such as a moist soil, are …

Effects Of Temperature On Moisture Conductivity In Unsaturated Soil, Richard O'Bannon Meeuwig

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water moves in soil in response to potential gradients. The basic equation for this movement is the generalized v=-K▽Φ in which v is volume of water passing through a unit area in unit time, K is the conductivity coefficient, ▽, is the gradient operator (vector), and ▽Φ is the potential gradient.

Relations Between Transpiration, Leaf Temperatures, And Some Environmental Factors, Ronald Kay Tew

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Transpiration is the loss of water in vapor form from a plant. This is essentially the same process as evaporation except that it is modified by plant structure. Large quantities of water are removed from the soil, transferred through the conducting tissues of the plant, and dissipated into the air each day. As soon as the water is lost to the atmosphere, it becomes unavailable for human use.