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Articles 31 - 41 of 41

Full-Text Articles in Physical Sciences and Mathematics

Electric Currents Due To Stress-Activated Positive Hole Charge Carriers In Ice, Cary T. Keller P.E., Friedemann T. Freund, Dale P. Cruikshank Aug 2012

Electric Currents Due To Stress-Activated Positive Hole Charge Carriers In Ice, Cary T. Keller P.E., Friedemann T. Freund, Dale P. Cruikshank

STAR Program Research Presentations

Jupiter’s satellite Europa, whose surface is composed of ice with a possible water ocean beneath, could conceivably serve as an abode for extraterrestrial life. This and other icy celestial bodies may contain organic macromolecular solid material that is produced when surface ices are exposed to ultraviolet radiation and/or electrical energy. Tidal and tectonic stresses or meteorite impacts in icy crusts may produce electrical discharges, which would provide the energy for in-situ synthesis of the organic solids. This electrical energy can be provided by positive hole charge carrier activation. Positive holes exhibit properties such as the ability to flow out of …


Investigation Of Spillover Effect To Enhance Hydrogen Storage, Sarah C. Corrigan, Lin Simpson, Thomas Gennett Aug 2012

Investigation Of Spillover Effect To Enhance Hydrogen Storage, Sarah C. Corrigan, Lin Simpson, Thomas Gennett

STAR Program Research Presentations

Hydrogen is an attractive energy option because of its low
environmental impact, but a critical problem is its low energy
density, which makes it difficult to store. For example, the US
Department of Energy (DOE) hydrogen plan for fuel cell powered
vehicles requires a gravimetric density of 6.5 wt%. There are several
existing hydrogen storage methods, including compressed gas,
liquefaction, metal hydrides, and physisorption, but at present, none
of these technologies comes close to achieving the targets set by the
DOE. Although chemical storage methods have been claimed to be the
most promising hydrogen storage technology, and activated carbons the …


Raman Mapping Of Mars Relevant Minerals Using Multiple Excitation Wavelenghts, Victoria Campbell, William Abbey Aug 2012

Raman Mapping Of Mars Relevant Minerals Using Multiple Excitation Wavelenghts, Victoria Campbell, William Abbey

STAR Program Research Presentations

The purpose of this project is to map Mars relevant minerals using the Raman instrument Horiba LabRam Raman. The Raman spectrometer is a non-invasive sampling technique used to identify mineral composition of various compositions by measuring the “Raman Shift” of each mineral. This was accomplished by using a green (532nm) laser which acted as a monochromatic light source. This source was absorbed by the sample and reemitted. The frequency of the reemitted photons are then shifted up or down in comparison with original frequency, which is referred to as the ‘Raman Effect’. The samples with shorter wavelengths produced a stronger …


Exploration Of Charge Carriers In Obsidian, Ryan Nordvik, Friedemann Freund Aug 2012

Exploration Of Charge Carriers In Obsidian, Ryan Nordvik, Friedemann Freund

STAR Program Research Presentations

This research effort is part of an ongoing investigation into stress-activated positive hole charge carriers in common igneous and high-grade metamorphic rocks. The findings have already revealed potential early earthquake detection mechanisms and caused a re-think on the processes that could conceivably contribute to the formation of and evolution of life. Positive holes are defect electrons in the oxygen anion sub-lattice of silicate minerals that have demonstrated some intriguing capabilities: flowing out of a stressed rock volume; causing oxidation reactions at the rock-water interface and ionization at the rock-air interface; and traveling great distances. This research seeks to determine if …


Leds And Astronomy, Britny N. Delp, Stephen M. Pompea Aug 2012

Leds And Astronomy, Britny N. Delp, Stephen M. Pompea

STAR Program Research Presentations

Using a Czerny-Turner spectrometer, 45 different types of outdoor lights were categorized. These spectra were used to determine how useful the light is to human eyes and how dark skies friendly these lights are. Dark skies friendly lighting means that little to no light shines above a right angle to the light, and should emit as little as possible below 500nm (green) wavelengths. The short wavelengths present a problem to astronomers in the form of Rayleigh scattering. The following criterion were used in selecting the best source for urban and rural lighting: color rendition measured by color rendering index (CRI), …


Rock Porosity Analysis Using High Resolution X-Ray Tomography, Leo Groner, Dula Parkinson, Katya Bazilevskaya Aug 2011

Rock Porosity Analysis Using High Resolution X-Ray Tomography, Leo Groner, Dula Parkinson, Katya Bazilevskaya

STAR Program Research Presentations

Understanding rock porosity, the fraction of rock volume that is in pores, is a key to modeling weathering and flow of water, petroleum and CO2 through geological structures. Weathering of rocks affects the CO2 cycle, nutrient cycle and soil formation. Rock porosity affects water flow rates and, in turn, affects weathering. Avizo software was used to explore, visualize and measure the reconstructed high-resolution X-ray micro-tomography data collected from scanned rocks. Many Avizo approaches were tried before arriving at an acceptable process to determine their porosity characteristics. Porosity dynamics are affected by weathering and lithification. At micron resolution, the image is …


Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown Aug 2011

Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown

STAR Program Research Presentations

Astrophysicists use radiation to investigate the physics controlling a variety of celestial sources, including stellar atmospheres, black holes, and binary systems. By measuring the spectrum of the emitted radiation, astrophysicists can determine a source’s temperature and composition. Accurate atomic data are needed for reliably interpreting these spectra. Here we present an overview of how LLNL’s EBIT facility is used to put the atomic data on sound footing for use by the high energy astrophysics community.


Relationships Between Snow Pack, Soil Moisture, And Forest Greenness: Implications For Smap, Jordan Anderson, Noah Molotch, Bin Guan Aug 2011

Relationships Between Snow Pack, Soil Moisture, And Forest Greenness: Implications For Smap, Jordan Anderson, Noah Molotch, Bin Guan

STAR Program Research Presentations

Snowpack in the arid/semi-arid western United States is a critical element of the hydrologic cycle as water is stored in the winter and released in the spring and summer. The warmer seasons rely heavily on this water source for various purposes including economic (farming), environmental and recreational demands. Moderate Imaging Spectroradiometer (MODIS) sensors were used in this project to measure seasonal variability in global vegetation phenology and productivity. MODIS data was used to calculate Normalized Difference Vegetation Index (NDVI) to estimate net primary production of subalpine forests in the Sierra Nevada mountain range. Preliminary results indicate that variability in forest …


Exploring Methods For Earthquake Prediction: The Effects Of Water On The Flow Of Stress-Activated Electric Currents In Igneous Rocks, Aaron M. Jahoda, Friedemann T. Freund Aug 2011

Exploring Methods For Earthquake Prediction: The Effects Of Water On The Flow Of Stress-Activated Electric Currents In Igneous Rocks, Aaron M. Jahoda, Friedemann T. Freund

STAR Program Research Presentations

Much of the devastation and damage of earthquakes can be attributed to the fact that they occur suddenly and without much warning, which limits the ability of people to evacuate and/or properly prepare. One method, however, that might be used to predict seismic events is the generation of electric currents in rocks when stresses are applied. It is observed in this research that the application of direct force onto samples of igneous rock causes the rocks to generate a measurable current, which is attributed to positive-hole charges moving within the oxygen sub-lattice. Because large and changing forces are acted upon …


Remote Sensing Analysis For Salinity Management Of Seasonal Wetlands, Debra L. S. Miller, Nigel W.T. Quinn Aug 2011

Remote Sensing Analysis For Salinity Management Of Seasonal Wetlands, Debra L. S. Miller, Nigel W.T. Quinn

STAR Program Research Presentations

A 170,000 wetland complex, including wetlands managed by the Grassland Water District (GWD), are located in California’s Central Valley in Merced County. The GWD is divided into North and South areas which are further divided into subareas. Historically, these wetlands were created by annual floods along the San Joaquin River that inundated the floodplain and created habitat for native wildlife, and over-wintering waterfowl. Today, these wetland areas are managed artificially with water supply provided from the Delta. Data from a real-time sensor network located along channels and at the inlets and outlets to and from individual ponds is being used …


A Study Of Ozone At Railroad Valley, Nv And Trinidad Head, Ca, Sarah L. Salazar, Laura T. Iraci, Emma L. Yates Aug 2011

A Study Of Ozone At Railroad Valley, Nv And Trinidad Head, Ca, Sarah L. Salazar, Laura T. Iraci, Emma L. Yates

STAR Program Research Presentations

A STUDY OF OZONE AT RAILROAD VALLEY, NV and TRINIDAD HEAD, CA

Ozone (Oᴣ) is a form of oxygen that protects the planet Earth from deadly ultraviolet rays emitted by the sun; without this triatomic molecule high in the atmosphere, life processes on the planet would be impossible. Ozone is an air pollutant and toxic in the lowest part of the atmosphere, and inhaling it could cause permanent damage to animals’ respiratory system. Long term exposure to high concentration of ozone has been linked with the development of asthma in children. Because of its complicated role in our atmosphere, scientists …