Using Solar Energy, 2010 University of Massachusetts Amherst
Using Solar Energy, Peter Talmage
Science and Engineering Saturday Seminars
• Best energy source for the environment • It’s getting more economical every day • Easy to maintain • Cuts down on foreign oil imports
Field-Induced Quantum Phase Transitions In The Spin-1/2 Triangular-Lattice Antiferromagnet Cs2cubr4, Nathanael Alexander Fortune, Scott T. Hannahs, Y. Takano, Y. Yoshida, T. Sherline, A. A. Wilson-Muenchow, T. Ono, H. Tanaka
Physics: Faculty Publications
In classical magnetic spin systems, geometric frustration leads to a large number of states of identical energy. We report here evidence from magnetocaloric and related measurements that in Cs2CuBr4 — a geometrically frustrated Heisenberg S= 1/2 triangular antiferromagnet — quantum fluctuations stabilize a series of gapped collinear spin states bounded by first-order transitions at simple increasing fractions of the saturation magnetization for fields directed along the c axis. Only the first of these quantum phase transitions has been theoretically predicted, suggesting that quantum effects continue to dominate at fields much higher than previously considered.
Closed Time-Like Curves And Inertial Frame Dragging: How To Time Travel Via Spacetime Rotation, 2010 Bucknell University
Closed Time-Like Curves And Inertial Frame Dragging: How To Time Travel Via Spacetime Rotation, Conrad Wilson Moore
As the number of solutions to the Einstein equations with realistic matter sources that admit closed time-like curves (CTC's) has grown drastically, it has provoked some authors  to call for a physical interpretation of these seemingly exotic curves that could possibly allow for causality violations. A first step in drafting a physical interpretation would be to understand how CTC's are created because the recent work of  has suggested that, to follow a CTC, observers must counter-rotate with the rotating matter, contrary to the currently accepted explanation that it is due to inertial frame dragging that CTC ...
Psc 307: Nuclear Weapons Arms Control, 2010 California Polytechnic State University - San Luis Obispo
Psc 307: Nuclear Weapons Arms Control, David Hafemeister
No abstract provided.
Psc 307: Nuclear Proliferation, 2010 California Polytechnic State University - San Luis Obispo
Psc 307: Nuclear Proliferation, David Hafemeister
No abstract provided.
Strain Within The Ultrahigh‐Pressure Western Gneiss Region Of Norway Recorded By Quartz Cpos, 2010 University of California - Santa Barbara
Strain Within The Ultrahigh‐Pressure Western Gneiss Region Of Norway Recorded By Quartz Cpos, Nicolas C. Barth, Bradley R. Hacker, Gareth G.E. Seward, Emily O. Walsh, David Young, Scott Johnston
Electron back‐scatter diffraction was used to measure the crystal preferred orientations (CPOs) from 101 samples across the ultrahigh‐pressure Western Gneiss Region of Norway to assess slip systems, sense of shear, CPO strength, and strain geometry. The CPOs suggest a dominance of prism slip, with lesser amounts of prism [c] slip and basal slip; there are few Type‐I and Type‐II girdles. The major structural feature in the study area—the high‐strain, top‐W, normal‐sense Nordfjord–Sogn Detachment Zone—is characterized by asymmetric and strong CPOs; an eastern domain with strong asymmetric CPOs shows top‐E ...
Interlayer Exchange Coupling Across A Ferroelectric Barrier, 2010 University of Nebraska-Lincoln
Interlayer Exchange Coupling Across A Ferroelectric Barrier, M Ye Zhuravlev, A V. Vedyayev, Evgeny Y. Tsymbal
Evgeny Tsymbal Publications
A new magnetoelectric effect is predicted originating from the interlayer exchange coupling between two ferromagnetic layers separated by an ultrathin ferroelectric barrier. It is demonstrated that ferroelectric polarization switching driven by an external electric field leads to a sizable change in the interlayer exchange coupling. The effect occurs in asymmetric ferromagnet/ferroelectric/ferromagnet junctions due to a change in the electrostatic potential profile across the junction affecting the interlayer coupling. The predicted phenomenon indicates the possibility of switching the magnetic configuration by reversing the polarization of the ferroelectric barrier layer.
Spectral Shifts And Switches In Random Fields Upon Interaction With Negative-Phase Materials, 2010 University of Miami
Spectral Shifts And Switches In Random Fields Upon Interaction With Negative-Phase Materials, Zhisong Tong, Olga Korotkova
Physics Articles and Papers
Spectral shifts in stochastic beam-like fields on interaction with layers of positive- and negative-phase materials are examined on the basis of the ABCD-matrix approach and generalized Huygens-Fresnel principle. It is found that boundaries between such materials may cause spectral switches. Effect of absorption of negative-phase materials on the beam spectrum is discussed. Our results may find applications in connection with spectrum-selection optical interconnects, spectrally encoded information transfer, image formation in systems involving negative-phase materials, and geometrically tunable metamaterials.
Stochastic Electromagnetic Beams In Positive-And Negative-Phase Materials, 2010 University of Miami
Stochastic Electromagnetic Beams In Positive-And Negative-Phase Materials, Zhisong Tong, Olga Korotkova
Physics Articles and Papers
Theoretical analysis of interaction of stochastic electromagnetic beamlike fields with positive- and negative-phase materials suggests that suitable combinations of such materials can serve as media where spectral, coherence, and polarization properties of beams can self-reconstruct.
Theory Of Weak Scattering Of Stochastic Electromagnetic Fields From Deterministic And Random Media, 2010 University of Miami
Theory Of Weak Scattering Of Stochastic Electromagnetic Fields From Deterministic And Random Media, Zhisong Tong, Olga Korotkova
Physics Articles and Papers
The theory of scattering of scalar stochastic fields from deterministic and random media is generalized to the electromagnetic domain under the first-order Born approximation. The analysis allows for determining the changes in spectrum, coherence, and polarization of electromagnetic fields produced on their propagation from the source to the scattering volume, interaction with the scatterer, and propagation from the scatterer to the far field. An example of scattering of a field produced by a δ-correlated partially polarized source and scattered from a δ-correlated medium is provided.
The Longitude Problem From The 1700s To Today: An International And General Education Physics Course, 2010 California Polytechnic State University - San Luis Obispo
The Longitude Problem From The 1700s To Today: An International And General Education Physics Course, Thomas J. Bensky
For instructors wishing to use physics as part of an international or general education course, the framework for a course based on the “longitude problem” from the 1700s is described. The longitude problem is teeming with basic principles of physics and astronomy, which makes it ideal for a non-science-major-based college-level course. This paper summarizes the longitude problem in the context of conceptual physics and astronomy and outlines an appropriate curriculum. Specifics on teaching such a course in London, as part of an international studies program, are discussed.
Web-Based Student Data Collection And Assessment, 2010 California Polytechnic State University - San Luis Obispo
Web-Based Student Data Collection And Assessment, Thomas J. Bensky
Gathering information from students for learning assessment is a critical need of any teacher. In this paper, the tech-savvy instructor is introduced to basic techniques of creating custom, web-based, student-data collection software. Despite widespread deployment of generalized course management systems, the author argues that small, ultra-customized data collection methodologies, can be of great help in collecting and assessing student input, reducing demands on paper, and easing the familiar grading bottleneck while satisfying an individual's pedagogical needs.
Harvesting Single Ferroelectric Domain Stressed Nanoparticles For Optical And Ferroic Applications, 2010 Air Force Research Laboratory
Harvesting Single Ferroelectric Domain Stressed Nanoparticles For Optical And Ferroic Applications, Gary Cook, J. L. Barnes, S. A. Basun, Dean R. Evans, Ron F. Ziolo, Arturo Ponce, Victor Yu. Reshetnyak, Anatoliy Glushchenko, Partha P. Banerjee
Electrical and Computer Engineering Faculty Publications
We describe techniques to selectively harvest single ferroelectric domain nanoparticles of BaTiO3 as small as 9 nm from a plethora of nanoparticles produced by mechanical grinding. High resolution transmission electron microscopy imaging shows the unidomain atomic structure of the nanoparticles and reveals compressive and tensile surface strains which are attributed to the preservation of ferroelectric behavior in these particles.
We demonstrate the positive benefits of using harvested nanoparticles in disparate liquid crystal systems.
Computational Fluctuating Fluid Dynamics, 2010 San Jose State University
Computational Fluctuating Fluid Dynamics, Alejandro Garcia, J. B. Bell, S. Williams
This paper describes the extension of a recently developed numerical solver for the Landau-Lifshitz Navier-Stokes (LLNS) equations to binary mixtures in three dimensions. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by using white-noise fluxes. These stochastic PDEs are more complicated in three dimensions due to the tensorial form of the correlations for the stochastic fluxes and in mixtures due to couplings of energy and concentration fluxes (e.g., Soret effect). We present various numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate good agreement with theoretical results and molecular simulation
Studies Of Aspect Angle Dependence Of Plasma Turbulence At Haarp, 2010 Eastern Michigan University
Studies Of Aspect Angle Dependence Of Plasma Turbulence At Haarp, Nargis Adham
Master's Theses and Doctoral Dissertations
We report the results from a recent series of campaigns employing the HAARP HF transmitter to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. Diagnostics included the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the Super DARN-Kodiak HF radar, and HF receivers to record stimulated electromagnetic emissions (SEE). Short pulse, low duty cycle experiments demonstrate control and suppression of artificial field-aligned irregularities (AFAI). This allows the isolation of ponderomotive plasma turbulence effects. Plasma line spectra exhibit a marked dependence on the aspect angle of the HF pump beam and the pointing of ...
Earth‐Moon‐Mars Radiation Environment Module Framework, 2010 University of New Hampshire
Earth‐Moon‐Mars Radiation Environment Module Framework, Nathan A. Schwadron, L. Townsend, K. Kozarev, M. A. Dayeh, F. Cucinotta, M. Desai, M. Golightly, D. Hassler, R. Hatcher, M. Y. Kim, A. Posner, M. Pourarsalan, Harlan E. Spence, R. K. Squier
 We are preparing to return humans to the Moon and setting the stage for exploration to Mars and beyond. However, it is unclear if long missions outside of low-Earth orbit can be accomplished with acceptable risk. The central objective of a new modeling project, the Earth-Moon-Mars Radiation Exposure Module (EMMREM), is to develop and validate a numerical module for characterizing time-dependent radiation exposure in the Earth-Moon-Mars and interplanetary space environments. EMMREM is being designed for broad use by researchers to predict radiation exposure by integrating over almost any incident particle distribution from interplanetary space. We detail here the overall ...
Hadron Structure From Holographic Qcd, 2010 College of William & Mary - Arts & Sciences
Hadron Structure From Holographic Qcd, Zainul Abidin
Dissertations, Theses, and Masters Projects
The AdS/CFT correspondence relates a strongly coupled gauge theory in four dimensional space-time with a weakly coupled gravity theory in five dimensional space-time. This correspondence provides a way to access the strongly coupled regime of a gauge theory via a perturbative approach in its gravity dual theory. In this dissertation, the gravity dual of Quantum Chromodynamics (QCD) is discussed. The so-called bottom-up approach (AdS/QCD) successfully reproduces the low energy observables at 10-20% accuracy.;An AdS/QCD model with two flavors of quarks is considered, assuming isospin symmetry. Pions and rho mesons masses and decay constants are obtained. We ...
Efficiency Of Parallel Tempering For Ising Systems, 2010 University of Massachusetts Amherst
Efficiency Of Parallel Tempering For Ising Systems, Stephan Burkhardt
Masters Theses 1911 - February 2014
The efficiency of parallel tempering Monte Carlo is studied for a two-dimensional Ising system of length L with N=L^2 spins. An external field is used to introduce a difference in free energy between the two low temperature states.
It is found that the number of replicas R_opt that optimizes the parallel tempering algorithm scales as the square root of the system size N. For two symmetric low temperature states, the time needed for equilibration is observed to grow as L^2.18. If a significant difference in free energy is present between the two states, this changes to ...
Theoretical And Experimental Aspects Of The Higgs Mechanism In The Standard Model And Beyond, 2010 University of Massachusetts Amherst
Theoretical And Experimental Aspects Of The Higgs Mechanism In The Standard Model And Beyond, Alessandra Edda Baas
Masters Theses 1911 - February 2014
The Standard Model of particle physics is the best existing theory for describing the interactions between elementary particles. Even though the Standard Model has been confirmed in many experiments, there remain unanswered questions. One of the main questions is how fermions and most gauge bosons get masses; the Standard Model begins with them as massless. The Higgs effect is a mechanism to explain how fermions and several gauge bosons do get masses in the Standard Model. The corresponding Higgs boson is the only particle that has not yet been detected.
This Thesis gives a complete review of the Higgs effect ...
Efficient Modeling Techniques For Time-Dependent Quantum System With Applications To Carbon Nanotubes, 2010 University of Massachusetts Amherst
Efficient Modeling Techniques For Time-Dependent Quantum System With Applications To Carbon Nanotubes, Zuojing Chen
Masters Theses 1911 - February 2014
The famous Moore's law states: Since the invention of the integrated circuit, the number of transistors that can be placed on an integrated circuit has increased exponentially, doubling approximately every two years. As a result of the downscaling of the size of the transistor, quantum effects have become increasingly important while affecting significantly the device performances. Nowadays, at the nanometer scale, inter-atomic interactions and quantum mechanical properties need to be studied extensively. Device and material simulations are important to achieve these goals because they are flexible and less expensive than experiments. They are also important for designing and characterizing ...