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Full-Text Articles in Physical Chemistry

Pnnl Dark Matter Bubble Chamber, Ryan Robinson Aug 2018

Pnnl Dark Matter Bubble Chamber, Ryan Robinson

STAR Program Research Presentations

The Pacific Northwest National Laboratory (PNNL) prototype bubble chamber is intended to address issues encountered with the current PICO dark matter search detectors and improve the functionality of future experimental designs. The PNNL bubble chamber accomplishes this with a simplified interface between the hydraulic pressure controls and the target vessel and altering the standard chamber design such that it can be easily exchanged and replaced with vessels of various sizes and materials for testing purposes. The chamber itself is a glass vessel which houses perfluorobutane and holds the target fluid above room temperature and atmospheric pressure. The target fluid becomes …


X-Ray Spectroscopy Of Nio And Nanodiamond At Ssrl, Jackson Earl Jan 2018

X-Ray Spectroscopy Of Nio And Nanodiamond At Ssrl, Jackson Earl

STAR Program Research Presentations

The first aspect of this research project focuses on investigating the surface chemistry of high pressure high temperature (HPHT) nanodiamond by using X-ray spectroscopy techniques at the Stanford Synchrotron Radiation Lightsource (SSRL). HPHT nanodiamond is being examined as a biosensing tool for electric field detection based on the fluorescent nitrogen vacancy center hosted within diamond. With use of the transition edge spectrometer (TES), a state-of-the-art X-ray fluorescence detector, we are able to probe the surface and bulk properties of diamond. Preliminary work using density functional theory (DFT) has been done, offering insight into ground state energies and electronic structure. DFT …


Probing The Surface Of Nanodiamonds At Stanford Synchrotron Radiation Lightsource And San Jose State University, Jocelyn Valenzuela, Jackson Earl, Cynthia Melendrez, Grace Jeanpierre, Dennis Nordlund, Abraham Wolcott Jan 2018

Probing The Surface Of Nanodiamonds At Stanford Synchrotron Radiation Lightsource And San Jose State University, Jocelyn Valenzuela, Jackson Earl, Cynthia Melendrez, Grace Jeanpierre, Dennis Nordlund, Abraham Wolcott

STAR Program Research Presentations

The nitrogen-vacancy center in diamond is a promising tool in oncology, electric field sensing, and quantum cryptography. High-pressure high-temperature (HPHT) nanodiamonds (NDs) are prime contenders for these fields because they host nitrogen-vacancy centers (NVCs) which are applicable towards cancer detection and electric and magnetic field sensing. However, to apply HPHT NDs to these fields, the surface must first be functionalized—a difficult process because of the inert nature of the surface. The project at hand focuses on surface modification of HPHT NDs with amines to allow for further bioconjugation of small molecules and plasmonic shells. This is done via liquid-phase chemistry …


Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu Aug 2016

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …


Comparative Analysis Of In Situ Fibronectin Using Tof-Sims, Spi-Ms, And Dropdesi-Ms In A Microfluidic Reactor, Shannon Fasing, Xiao-Ying Yu, Juan Yao, Jiachao Yu Aug 2016

Comparative Analysis Of In Situ Fibronectin Using Tof-Sims, Spi-Ms, And Dropdesi-Ms In A Microfluidic Reactor, Shannon Fasing, Xiao-Ying Yu, Juan Yao, Jiachao Yu

STAR Program Research Presentations

Fibronectin is an important biomolecule due to its role in cell differentiation, growth, kinesis, and adhesion. Such biological responses are mediated through membrane recognition and signaling; where fibronectin is found. Studying the outer molecular surface of fibronectin allows deeper insight into the microbiological reactions that occur during these processes. In situ mass spectrometry analysis in aqueous solution accurately represents fibronectin’s chemical components, made possible by a vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface). SALVI was paired with the analytical tools: time-of-flight secondary ion mass spectrometer (ToF-SIMS), single photon ionization mass spectrometer (SPI-MS) and drop …


Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner Aug 2015

Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Low energy surfaces can strongly repel both oil and water. Recently these surfaces have been fabricated on various substrates including fabric, aluminum, stainless steel and many other materials. In this experiment we explore the use of low energy surface deposition on aluminum alloy, stainless steel and silicon substrates, to enhance the drying rate of liquids removed from the surface by forced convection. We control surface roughness by substrate abrasion and by the growth of Al2O3 nanograss to enhance liquid repellence by use of a hierarchical texture. Liquid repellence of the substrates is measured by contact angles of …


Determining Force Field Parameters Involved With Metal Organic Framework Synthesis, Marcus A. Tubbs, David Cantu, Vanda Glezakou Aug 2014

Determining Force Field Parameters Involved With Metal Organic Framework Synthesis, Marcus A. Tubbs, David Cantu, Vanda Glezakou

STAR Program Research Presentations

Metal organic frameworks (MOFs) are synthetic materials made of a cage-like lattice with consistently spaced pores. The size of these pores are the defining characteristic of a MOF, as it determines which gases are allowed to pass through and which can be trapped. Examples of their potential use can be greenhouse gas sequestration or storage. Currently, the synthesis of MOFs is based on trial-and-error, and the successes are not well understood. We are working on building the theoretical framework that describes how a particular MOF, MIL-101, comes together during synthesis. Our initial approach was to simulate the possible reactions with …


Does A Plastron Improve Heat Transfer?, Madani A. Khan, Jeffrey Alston, Andrew Guenthner Aug 2014

Does A Plastron Improve Heat Transfer?, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Superamphiphobic surfaces strongly repel both water and oils. In this work, aluminum coupons are processed by sanding with various grit of sand paper to impart microscale roughness. Subsequent submersion of the aluminum substrate in boiling water grows nanoscale grass-like structures. The oxide layer of Al is slightly soluble in water. During a fast diffusion/equilibrium, Al2O3 nanograss grows on the surface. A low energy coating is then deposited on the surface. The micro and nanoscale features create re-entrant structures that trap air enabling contact liquid to be in a Cassie-Baxter state. Superamphiphobicity of the samples were confirmed by …


Io3- And I- Sorption From Groundwater By Layered Double Hydroxides, Abbey Rickelmann, Emily Campbell, Natasha Pence, Tatiana Levitskaia, Sayandev Chatterjee, Frances Smith Aug 2013

Io3- And I- Sorption From Groundwater By Layered Double Hydroxides, Abbey Rickelmann, Emily Campbell, Natasha Pence, Tatiana Levitskaia, Sayandev Chatterjee, Frances Smith

STAR Program Research Presentations

Several subsurface water plumes are found at the Hanford U.S. DOE site. These plumes contain many different types of hazardous components including radioactive iodate (IO3-) and iodide (I-), which may have deleterious health effects. To selectively uptake IO3- and I-, inorganic layered double hydroxide (LDH) compounds were synthesized and tested. LDHs are mixed transition metal hydroxides that contain positively charged layers that undergo anion exchange. When LDHs are submerged in the plume water, they can selectively uptake IO3- and I- and remove them from the plume. Raman spectroscopy …


Characterization Of Uranium Species In Sediments Under Iron And Sulfate Reducing Conditions Using Synchrotron-Based Techniques, Don Q. Pham, John Bargar Aug 2011

Characterization Of Uranium Species In Sediments Under Iron And Sulfate Reducing Conditions Using Synchrotron-Based Techniques, Don Q. Pham, John Bargar

STAR Program Research Presentations

Uranium is one of the most common and problematic contaminants at legacy Department of Energy sites. Groundwater contamination is particularly problematic because it occurs at depth, is present in large volumes, and cannot be easily accessed for clean-up. One method of remediation being investigated is the bioreduction of soluble U(VI) to insoluble U(IV) complexes through the in-situ stimulation of metal-reducing bacteria. Understanding the structure of these uranium complexes can help us determine their fate and stability in groundwater and map out the biological process of uranium reduction by metal-reducing bacteria. In this study, we used the synchrotron-based techniques, X-ray absorption …


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 …