Physics Commons^™

Optical Techniques To Probe Internal Dynamics Of Soft Materials, Klebert Feitosa

Science Enabled by Photon Sources: Local Research Interests in Virginia

Like many other soft materials, foam displays complex fluid behavior. Under different circumstances it may behave like an elastic solid or a typical fluid depending on driving forces and the interactions between individual bubbles. To understand the inherent complexities of foam flow, an effective method to visualize its internal structure and dynamics is paramount. In this talk, I will introduce two techniques we have used in our lab to probe foam dynamics at the bubble level: optical tomography and confocal microscopy. The results show great promise to unveil the internal mechanisms that lead to the complex fluid behavior of foams.

X-Ray Fluorescence Microscopy: A Tool For Biology, Life Science & Nanomedicine, Stafan Vogt

Science Enabled by Photon Sources: Local Research Interests in Virginia

Trace elements, in particular metals, play a significant role in most known life forms. It is estimated that one-third of all known proteins contain metal cofactors, and the majority of these function as essential metalloenzymes catalyzing biochemical reactions. Trace metals are increasingly recognized as having a critical impact on human health both in their natural occurrence and via therapeutic drugs (e.g., environmental exposure to heavy metals, treatment with cisplatin-based drugs in chemotherapy, ...), and in diseases such as Alzheimer’s. Quantitative study of the distribution of trace elements on the cellular and subcellular level provide important information about functions and pathways …

Harvesting Heat Through Seebeck Spin Tunneling Effect, Costel Constantin

Science Enabled by Photon Sources: Local Research Interests in Virginia

Harvesting the wasted heat released in the atmosphere by electronic devices has become an important issue in microelectronics as devices shrink toward nanoscale dimensions while achieving an increase in operating speed. Spintronic devices that make use of electrons’ spin as an information carrier offer a promising path to create novel efficient devices thus reducing this wasted heat. Thermoelectronics, on the other hand, explores the possibility of converting heat into electrical power. Spin caloritronics is an exciting new research field that takes advantage of both spintronics and thermoelectronics. In this talk, I will present the design of a spin caloritronic device …

The Role Of Photon Sources In Materials Research: Past, Present, & Future, E. Ward Plummer

Science Enabled by Photon Sources: Local Research Interests in Virginia

In this lecture I will trace the development of Light Sources from the early days of parasitic operation to the new billion dollar dedicated facilities. Clearly, the mode of usage has changed, but so has the type of user. How have these facilities balanced the need for beyond the state-of-the art experiments and serving the needs for routine characterization of materials? How can and should these facilities address the needs for the development of a workforce needed for the next generation of machines and science? Have they produced the science and scientists anticipated? Where do we go next, what is …

Pmma Nanocomposites Composed Of Optically Active Doped Inorganic Nanocrystals, Kyle Gipson

Science Enabled by Photon Sources: Local Research Interests in Virginia

As technology advances, more efficient, cost-effective materials and processes are being developed to serve the duties of optical materials within networks. As light transfers data through polymer optical materials, the polymeric matrix absorbs the signal and this phenomenon is known as attenuation. Attenuation occurs via the higher vibrational energies with respect to fluoropolymers that are inherent with hydrocarbon amorphous polymers like polymethyl methacrylate (PMMA).

One solution to realize efficient light emission is to incorporate nanoparticles into the polymer matrix. In the research presented, aqueous solution-polymer precipitation was used to synthesize light harvesting ligand capped luminescent nanoparticles. Tb3+:LaF3 was the chromophore …

Optical Properties& Energy Transfer Dynamics Of Atmospheric Species, Daniel K. Havey

Science Enabled by Photon Sources: Local Research Interests in Virginia

Our research group is interested in how light interacts with small molecules and particulate matter that are important to atmospheric chemistry and climate change. An active project currently being performed in the James Madison University Undergraduate Laser Laboratory involves a detailed mapping of energy transfer rates from excited or metastable states of atomic or molecular species. This talk describes a specific example study with potential relevance to the JLAMP VUV/Soft X-ray User Facility that would investigate relaxation dynamics of metastable Krypton atoms using two-photon photoacoustic spectroscopy at 819 nm and 124 nm. A study like this would provide useful reference …

Surface Modification & Characterization Of Nano-Composite Polymers, Chris Hughes, Brian Augustine

Science Enabled by Photon Sources: Local Research Interests in Virginia

We have studied the modification of surfaces of both PMMA and nano-composite polyhedral oligomeric silsesquioxane (POSS) containing acrylics. These nano-composites can be spun cast from a variety of solvents and the surface chemistry can be modified by exposure to oxygen-containing plasmas. However, we have found that interesting surface structure evolve over the space of several hours after these films are deposited. We have also found that the solvent used for the spin casting of these layers can alter the behaviors of these surfaces. In particular, we found that halogenated solvents can form complexes with the PMMA backbone to increase the …

Research Potential Of The Twisted Photon Beams, Andrei Afanasev

Science Enabled by Photon Sources: Local Research Interests in Virginia

The fact that photon beams can carry large orbital angular momenta was pointed out in a pioneering work by Allen and collaborators [1] and was later demonstrated experimentally. When quantized, such beams can be described in terms of twisted photons [2] that have a peculiar property: their total angular momentum projected on the direction of propagation may range from a few to hundreds of units of h. Accelerator-based light sources may generate such twisted light with high intensities, leading to new applications in several fields of physics. Examples of such applications will be presented in this talk.

[1.] L. Allen …

Development Of A 60,000 Rpm X-Ray Chopper With 25 Nsec Phase Jitter For Crystallography, Eric Maslen

Science Enabled by Photon Sources: Local Research Interests in Virginia

A high speed X-Ray chopper (mechanical shutter) was developed for sub microsecond time-resolved photocrystallography using a synchrotron source. Based on a rim-slotted titanium wheel rotating at a nominal 60,000 r/min, the device has an upper bound timing alignment (aperture passage compared to source pulse edge) jitter of 23 nsec RMS and has been operated consistently at jitters as low as 7 nsec RMS. The spindle was derived from a commercial turbo-molecular pump whose drive was adapted in a fairly simple manner to enable fine control by a secondary wheel phase regulator using conventional, off-the-shelf components. Because the spindle uses magnetic …

Imaging And Rheology Of Complex Granular & Granular-Fluid Flows, Brian Utter

Science Enabled by Photon Sources: Local Research Interests in Virginia

Granular materials are ubiquitous in nature and industry, from avalanches to the mixing of pharmaceuticals, yet the behavior of these “fluids” is poorly understood. While individual particles interact simply through friction and inelastic collisions, the non-linear forces and large number of particles leads to an unpredictable, complex system. History dependence, strong fluctuations and sudden failure are commonly observed, making predictive equations of macroscopic flow difficult or impossible to determine. Our recent work focuses on jamming, avalanching and shear banding in dense granular and granular-fluid flows and, in particular, the effects of external vibration and surface chemistry on flow properties. Ongoing …

University Scholar Series: Alejandro Garcia, Alejandro Garcia

University Scholar Series

Collaborating with DreamWorks

On April 25, 2012 Professor Alejandro Garcia spoke in the University Scholar Series hosted by Provost Ellen Junn at the Dr. Martin Luther King, Jr. Library. Professor Alejandro Garcia developed and teaches Physics of Animation, a science course for visual artists. During 2011, he took a professional leave and worked in DreamWorks Animation's department of Artistic Development as a physics consultant on Madagascar 3: Europe's Most Wanted. In this seminar, Alejandro Garcia describes the animation industry from both the scientific and artistic perspectives

Session E-1: Self-Paced Proficiency Based Physics – Updates And Extensions, Brooke Schmidt, Eric Hawker

Professional Learning Day

This presentation will cover how a typical introductory physics course has been transformed into one that is self-paced and proficiency graded. The changes were made so that each student would be challenged at his/her level and therefore be more engaged in the course. This structure allows the teacher to individualize instruction of the students. The presentation will also cover adjustments that were made to this model based on student feedback and experiences. The model used to make this course self-paced and proficiency graded should be transferable to other courses.

Session D-6: Teaching Modern Physics, Peter Dong

Professional Learning Day

Modern physics is an excellent way to get students interested in physics – the “weirdness” of relativity and quantum mechanics captures the imagination. This presentation discusses how to teach the subject in a way that encourages this interest. This year’s session will focus on teaching quantum mechanics in a way that is interesting to students and avoids common misconceptions.

The Unlv Xps Facility – Research Opportunities, Allen L. Johnson

NSTec UNLV Symposium

XPS Outline

•XPS – what is it?

•How is it done?

•What are its limitations?

•Future direction – radioactive samples

–Sample containment and transport
–Sputter controls
–Radiation limits

•Summary

Development Of Ion Beam Nuclear Transmutation Doping (Ibntd) For Novel Electronics In Extreme Conditions, Michael G. Pravica, Noel A. Guardala, Jack L. Price

NSTec UNLV Symposium

Development of IBNTD for electronics under extreme conditions.

•We hope to create novel wide bandgap devices using Ion Beam Nuclear Transmutation Doping (IBNTD). These devices may be used as rugged high power switches, and high current/low noise amplifiers. Diamond in itself represents a “Holy Grail” for electrical applications due to its very high thermal conductivity and excellent electrical characteristics.
•We also hope to develop devices that can convert the enormous energy from high-energy nuclear particles (α2+,β-,β+, γparticles) into useful electricity and thus harness the enormous energy still contained in “spent” nuclear fuel. Developing these direct energy conversion (DEC) devices would …

Overview Of Nstec Plasma Focus Tubes And Magnetohydrodynamic Modeling Capabilities, Tim Meehan

NSTec UNLV Symposium

•Brief Description of how DPFs work, in general what they are useful for.
•DPF devices that we have at NSTec
•Using MHD modeling software to optimize designs and predict performance
•Neutron Resonance Spectroscopy

Pmts And Radiation/Particle Detection Technologies, Brent Davis

NSTec UNLV Symposium

Describes technical standards for equipment in the field of Nuclear and Optical Physics.

National Center For Nuclear Security, Veraun Chipman, Amanda Klingensmith, Cathy Snelson

NSTec UNLV Symposium

National Center for Nuclear Security (NCNS) Mission

•Chartered mission is to enhance the Nation’s verification and detection capabilities in support of nuclear arms control and nonproliferation through R&D activities at the NNSS
•Three focus areas
–Treaty Verification Technologies
–Nonproliferation Technologies
–Technical Nuclear Forensics

Session G: Nuclear Power/Climate Change – Terrapower’S Traveling Wave Reactor, Tyler Ellis

Climate Change and the Future of Nuclear Power

TerraPower is moving forward with detailed plans for a sustainable, economic, and safe nuclear reactor. The Travelling Wave Reactor (TWR) – a reactor in the 500-megawatt electric range – uses unique core physics to initiate a breed and burn wave which can be completely sustained in fertile material. This process allows the TWR to convert depleted uranium waste into usable fuel as the reactor operates, providing a sustainable base-load power source. TerraPower is the first company to create a practical engineering embodiment of this previously studied concept thanks to a powerful advanced reactor modeling interface, developed in-house, which enables the …

Session G: Nuclear Power/Climate Change – Climate V. Climate Alarm, Richard S. Lindzen

Climate Change and the Future of Nuclear Power

The underlying physics of climate contains important elements that are widely agreed on though frequently misunderstood. In this lecture, the basic physics of greenhouse warming are simply described. It will be shown that the dynamic mixing of the troposphere is essential to the mechanism. It will further be shown that there is nothing intrinsically alarming in the basic physics. Alarm depends critically on the assertion that the climate system is dominated by large positive feedbacks that greatly amplify such warming as may be due to increasing CO2 alone. The nature of possible feedbacks will be described, and the conditions for …

Session B: The Future Of Nuclear Power - Aim High! Thorium Energy Cheaper Than From Coal, Cavan Stone

Climate Change and the Future of Nuclear Power

This century, we face significant environmental challenges. Our demand for limited natural resources is rapidly increasing and much of humanity is concerned about the consequences. Our unsustainably growing population drives these challenges, and humanely stabilizing it would alleviate these pressures. Demographic data clearly shows that prosperity stabilizes population and it also shows that prosperity critically requires energy. In spite of the pressing and demonstrable nature of these challenges however, politically there is no international consensus on global energy policy. Developing nations simply will not accept a policy that will hamper their economic growth. Yet, we do have a solution to …

Session B: The Future Of Nuclear Power - The Fukushima Nuclear Event And Its Implications For Nuclear Power, Michael W. Golay

Climate Change and the Future of Nuclear Power

The combined strong earthquake and super tsunami of 12 March 2011 at the Fukushima nuclear power plant imposed the most severe challenges ever experienced at such a facility. Information regarding the plant response and status remains uncertain, but it is clear that severe damage has been sustained, that the plant staff have responded creatively and that the offsite implications are unlikely to be seriously threatening to the health, if not the prosperity, of the surrounding population. Reexamination of the regulatory constraints of nuclear power will occur worldwide, and some changes are likely; particularly concerning reliance upon active systems for achieving …

Session B: The Future Of Nuclear Power - The Fundamentals And Status Of Nuclear Power, Regis A. Matzie

Climate Change and the Future of Nuclear Power

Nuclear power has enormous potential to provide clean, safe base-load electricity to the world’s growing population. Harnessing this potential in an economic and responsible manner is not without challenges. Safety remains the principal tenet of our operating fleet, which currently provides ~20% of U.S. electricity generated. The performance of this fleet from economic and safety standpoints has improved dramatically over the past several decades. This nuclear generation also represents greater than 70% of the emission free electricity with hydroelectric power providing the majority of the remainder. There have been many lessons learned from the more than 50 years of experience …

Conference Poster, Gerald Peterson

Climate Change and the Future of Nuclear Power

No abstract provided.

High Pressure Structural Studies On Nb5si3 Up To 26.2 Gpa, Brandon Stewart, Ravhi S. Kumar

Undergraduate Research Opportunities Program (UROP)

With the use of synchrotron techniques, we can better understand how crystalline structures behave under extreme conditions. This yields the opportunity to resolve complex crystal structures [1]. Here, we focus on the high pressure crystal structure of Nb5Si3. Refractory metal silicides are an important class of materials as they are used in high temperature applications such as turbines and aerospace modules. As an example, the performance of a jet engine is highly influenced by the maximum internal pressure and temperature possible. Obtaining higher levels of thrust is dependent upon the material's ability to remain structurally sound under extreme temperatures and …

High Pressure Study Of 1,1-Diamino-2,2-Dinitroethene With Raman Spectroscopy, Jack Brangham, Michael Pravica, Martin Galley

Undergraduate Research Opportunities Program (UROP)

The goal of this experiment is to better understand the reasons for Fox-7s insensitivity and high performance. It is very similar to other explosives in composition but different in structure. This different structure is believed to be the reason for Fox-7s unique characteristics. Using Raman spectroscopy along with high pressure techniques we hope to better understand this molecule and how it handles extreme conditions.

Ionic Alkalihalides As Pressure Media In Dac Experiments, Julius Monello

Undergraduate Research Opportunities Program (UROP)

In Diamond Anvil Cells (DACs), usually a pressure transmitting medium functions to transform the uniaxial pressure supplied by the opposing diamond anvils into uniform hydrostatic pressure acting on the sample. Conventionally, a 4-1 methanol-ethanol solution, or a 16-3-1 methanol-ethanol-water solution is used as pressure transmitting medium. However, these two solutions transform into a glass with high elastic shear strength at pressures around 12-14 GPa and no longer function as hydrostatic medium. Our goal was to determine if liquid ionic alkalihalide alkanolate complexes will provide more uniform pressure in the cell up to 20 GPa. Ruby (Cr-doped AlP,) produces two Cr"+ …

Neutron Diffraction Of Nabd4: Phase Transition, Rietveld Structure Refinements, And Equation Of State, Guillermo Esparza, Esparza, Patricia Kalita, Andrew Cornelius

Undergraduate Research Opportunities Program (UROP)

NaBH4 is a hydride with possible applications as a hydrogen storage material for future renewable energy technologies. It’s dehydrogenation properties are enhanced with the mixture of particular catalysts through ball-milling techniques during which local pressures may exceed several GPa’s. It is for this reason that understanding the behavior of pressure induced phase changes of its crystalline unit cell is an area of interest.

Second Hyperpolarizability Of Carbon Tetrachloride, Phillip C. Lotshaw, Anna M. Smith, David P. Shelton

Undergraduate Research Opportunities Program (UROP)

Although present theories of nonlinear optics agree with observed behavior in simple atoms such as helium, more complex molecules containing many electrons, such as carbon tetrachloride (CCI4), cannot consistently be described by theory. Through experimental analysis of nonlinear materials, a new, more sophisticated model for describing their properties could be realized. The purpose of our experiment was to measure the nonlinear behavior of the second harmonic signal generated from CCI4 and to compare the results with the prediction by the CCSD(T) molecular model.

Crystal Structural Behavior Of Cocu₂O₃ At High Temperatures, April Jeffries, Ravhi S. Kumar, Andrew L. Cornelius

Undergraduate Research Opportunities Program (UROP)

High temperature structure of CoCu₂O₃ The spin ladder compounds have received much attention recently due to their relation to the high transition temperature superconductivity. Also the study of spin ladder compounds is of great interest to explore the specific characteristics that result in their behavior. The CoCu₂O₃ spin ladder crystal structure is similar to SrCu₂O₃, which is apparent composition for many high temperature superconductors. The effects of temperature on structural change are investigated for this system. High temperature x-ray diffraction patterns were collected up to 1000⁰C and the variation of lattice parameters as a function of temperature up to decomposition …