Physics Commons^™

Studies Of Molecular Dynamics Of Fmoc Amino Acids Using Solid State Deuteron Nuclear Magnetic Resonance Spectroscopy, Wei Xu

Dissertations, Theses, and Masters Projects

The purpose of devising and validating models for intramolecular motions for FMOC amino acids is to quantify side chain motion in proteins which plays an important role in understanding biological structure function relations of proteins. In this thesis, spin lattice relaxation times (Ti) of FMOC amino acids were m easured under both static and magic angle spinning (MAS) condition at variable tem peratures. Lower activation energies of the relaxation times than the normal amino acids observed indicate a less sterically crowded environment for the rotation methyl group. A three-site jump model for the methyl group w as developed to fit …

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 …

Measurements Of Linestrengths, N2-, Ar-, He- And Self-Broadening Coefficients Of Acetylene In The Ν4+Ν5 Combination Band Using A Cw Quantum Cascade Laser, Muhammad Bilal Sajid, Et-Touhami Es-Sebbar, Aamir Farooq

Dr. Et-touhami Es-sebbar

Linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene have been measured at 296 K in the P branch of the ν4+ν5 combination band for 25 rotational transitions. The effect of gas temperature is studied over 296–683 K for five transitions to allow the determination of the temperature dependent exponent n for N2- and Ar-broadening coefficients. These measurements were performed using a continuous-wave quantum cascade laser (cw-QCL) operating over 1253–1310 cm−1. Spectroscopic parameters were obtained by fitting absorption spectra using Voigt, Galatry and Rautian profiles. Linestrength and broadening results are compared with previous studies available in literature for the ν4+ν5 …

Understanding The Plasmonic Properties Of Metallic Nanostructures With Correlated Photon- And Electron-Driven Excitations, Vighter Ozezinimize Iberi

Doctoral Dissertations

The collective oscillation of the conduction band electrons in metal nanostructures, known as plasmons, can be used to manipulate light on length scales that are smaller than the diffraction limit of visible light. In this dissertation, a correlated approach is used to probe localized surface plasmon resonances (LSPRs) in metallic nanostructures, and their application to surface-enhanced spectroscopy. This correlated approach involves the measurement of LSPRs with dark-field optical microscopy (resonance-Rayleigh scattering), and electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). Structural parameters of the exact same nanostructures obtained from the STEM are subsequently used in performing fully …

The Electrochemistry Of Hydrogen Peroxide On Uranium Dioxide And The Modelling Of Used Nuclear Fuel Corrosion Under Permanent Disposal Conditions, Linda Wu

Electronic Thesis and Dissertation Repository

This thesis reports a series of investigations examining the corrosion process of used nuclear fuel under permanent disposal conditions. The motivation of the project is that the safety assessment of deep geological disposal of spent nuclear fuel requires a fundamental understanding of the processes controlling fuel corrosion which could lead to the release of radionuclides to the geosphere from a failed container.

One primary objective of this project was to develop a computational model in order to simulate fuel corrosion under the disposal conditions. A series of simulations based on COMSOL were designed and developed to determine the influence of …

Evaluation Report, Alan Peterfreund

STEM Digital

This evaluation report synthesizes the results of evaluation activities conducted by SageFox Consulting Group of the STEM DIGITAL project led by the UMass STEM Ed Institute for its no-cost extension year, covering the period September 2013 to August 2014. The goals of the program are to facilitate the participants’ abilities to stimulate student interest in STEM careers while engaging them in ways to think critically about their environment. Participating teachers incorporated digital cameras and Analyzing Digital Images (ADI) software into lab activities focusing on environmental science. STEM DIGITAL materials focused on three strands related to (1) ozone and air quality, …

K-Shell X-Ray Spectroscopy Of Atomic Nitrogen, M. M. Sant'anna, Gunnar Ohrwall, Wayne C. Stolte, Alfred S. Schlachter, Dennis W. Lindle, B. M. Mclaughlin

Chemistry and Biochemistry Faculty Research

Absolute K-shell photoionization cross sections for atomic nitrogen have been obtained from both experiment and state-of-the-art theoretical techniques. Because of the difficulty of creating a target of neutral atomic nitrogen, no high-resolution K-edge spectroscopy measurements have been reported for this important atom. Interplay between theory and experiment enabled identification and characterization of the strong 1s → np resonance features throughout the threshold region. An experimental value of 409.64 ± 0.02 eV was determined for the K-shell binding energy.

Rational Design And Advanced Fabrication Of Metallic Nanostructures For Surface-Enhanced Raman Spectroscopy, Betty Cristina Galarreta

Electronic Thesis and Dissertation Repository

One of the main challenges in analytical science and technology is to develop devices that provide unambiguously the chemical nature of the material of interest with the minimum intrusiveness, the smallest amount of analyte, and the shortest acquisition time. Among the promising methods for such purpose, optical spectroscopy such as surface-enhanced Raman scattering is considered a suitable option. This spectroscopic technique takes advantage of the interaction between an optical field and metallic nanostructures to magnify the electromagnetic field in the vicinity of the nanostructure, resulting in an amplified signal of the vibrational fingerprints of the adsorbed molecules onto the metallic …

Extraction Chromatographic Studies Of Rutherfordium And Dubnium Homologs, Megan E. Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Studying the chemistry of transactinide elements does not only allow for these elements to be properly placed in the Periodic Table, but it also permits for the extrapolation of the electronic structure based upon the position of the element in the Periodic Table. In addition it enable for the assessment of the role that relativistic effects play in the chemical behavior of the heaviest elements. An improved understanding of the role of relativistic effects in chemistry of the heaviest elements allows for a better understanding of the fundamentals principles that govern the Periodic Table. In order to investigate the chemistry …

Institute Overview, Morton Sternheim

STEM Digital

Digital cameras and computers are widely available for students and teachers. However, they are mainly used for documentation: creating PPT presentations, handouts, posters, etc. STEM DIGITAL shows how digital image analysis can be applied to environmental (and other) research in STEM courses. Application to studies of air quality, water quality, arsenic contamination, climate change, diffusion, etc.

Digital Camera Basics, Stephen Schneider

STEM Digital

No abstract provided.

Measuring Lengths And Areas With Adi. Student Guide, Morton Sternheim

STEM Digital

No abstract provided.

Measuring G With Movie Tracker, Stephen Schneider

STEM Digital

No abstract provided.

Detecting And Mixing Colors, Rob Snyder

STEM Digital

How can Analyzing Digital Images software reveal the differences between primary colors of light and primary colors of paints or pigments?

Measuring The Acceleration Of Falling Objects, John Pickle

STEM Digital

Earth's gravity pulls all objects toward its center, and near the Earth's surface. Objects in free fall accelerate at 9.8 m/s² vertically downward, provided air resistance is negligible. This value of acceleration is often referred to as "g". There are many ways to measure this rate of acceleration, and most require a timing device. Typically, stopwatches are the least expensive technology, so these are commonly available in high school science classrooms. With the recent addition of movie cameras on cell phones and digital cameras, another timing tool is available at moderate cost (free if the school policy …

Leaf Leaching Experiment, David Reckhow

STEM Digital

Water treatment engineers and public health officials need to pay careful attention to the presence of dissolved organic matter in water supplies selected for human consumption (i.e., raw drinking waters).

Measuring Albedo With Adi - An Intensity Application, Morton Sternheim

STEM Digital

Why are Polar Regions more affected by global warming than other parts of the globe? One reason (there are others) is that as sea ice melts and more open water appears, more energy is absorbed, and warming accelerates. This is a form of positive feedback and it makes the polar climate change faster than the climate in temperate areas. Increasing vegetation on land also has a similar positive feedback effect. This effect is a change in the albedo – the fraction of the incident sunlight that is reflected back to space.

Stem Digital And Adi In The Classroom, Jennifer Welborn

STEM Digital

Applications of ADI by students at Amherst Regional Middle School

Co2 Diffusion Through Gelatin Experiment, Jennifer Welborn

STEM Digital

An example of measuring lengths.

Natural Organic Matter In Water, David Reckhow

STEM Digital

Formation in Watersheds and Removal in Water Treatment

Using Adi To Quantify A Color Change In Crayfish, Jennifer Welborn

STEM Digital

Do Crayfish Change Color If Their Environment Changes? A Guided Inquiry Lab for 7th grade Life Science

Background: There is anecdotal evidence from bass fisherman that crayfish are able to change color depending on their surroundings. A (cursory) literature review of this phenomenon showed that no formal research has been done in this area. Students had an additional informal lesson about research funding (or lack thereof) because of this finding.

Students designed and conducted a controlled experiment to see the effect of changing environment color on crayfish color.

ADI was used to quantify a color change.

Human Variation In Skin Color And Race As A Social Construct, Jennifer Welborn

STEM Digital

This lesson is part of evolution unit which follows heredity and genetics

The lesson is interdisciplinary in nature in that I discuss the concept of race as a social construct and the idea that there are “black, white, red, yellow” skinned people is something that people developed. It is not based on biology. Race groupings are human-made groups.

Students first learn about mixing light and how to determine black and white from an ADI analysis. They learn that red and green = yellow, etc.

They then photograph each other’s forearms and analyze the images using ADI.

We then discuss skin …

Air Quality: Carbon Dioxide, Deborah Carlisle, Stephen Schneider

STEM Digital

Measuring CO2 with BTB and ADI.

Measuring Angles With Adi, Stephen Schneider

STEM Digital

No abstract provided.

Analyzing Digital Images (Adi) Resources, Rob Snyder

STEM Digital

Basic introduction to installing and using ADI

Arsenic Project Topics, Julian Tyson

STEM Digital

How do analytical chemists make light work in tracking potentially harmful chemicals?

Water Treatment Experiments, David Reckhow

STEM Digital

•The water industry spends a lot of money and effort on removal of natural organic matter (NOM) from drinking waters •Problems with NOM (the more NOM the bigger problem) –NOM interferes with the ability of water treatment systems to remove substances that cause disease •Pathogenic organisms •Toxic chemicals –NOM reacts with chlorine‐based disinfectants forming carcinogenic organic byproducts

Experimental Design For Ozone Projects, Deborah Carlisle, Stephen Schneider

STEM Digital

No abstract provided.

An Optical Nose Approach To Explosive Detection.Pdf, Tabetha Osborn, Joshua Green, William A. Burns, Scott Reeve

Scott Reeve

No abstract provided.

Chemical And Electronic Structure Of Surfaces And Interfaces In Compound Semiconductors, Sujitra Pookpanratana

UNLV Theses, Dissertations, Professional Papers, and Capstones

The interface formation between two different materials is important in applications for optoelectronic devices. Often, the success or performance of these devices is dependent on the formation of these heterojunctions. In this work, the surface and interfaces in such materials for optoelectronic devices are investigated by a suite of X-ray analytical techniques including X-ray photoelectron (XPS), X-ray excited Auger electron (XAES), and X-ray emission (XES) spectroscopies to provide novel insight.

For the group III-nitrides (e.g., AlxGa1-xN) used in many light emitting devices, a significant challenge exists to form an Ohmic contact. The electron affinities and band gaps of GaN and …