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2016

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Articles 1 - 30 of 769

Full-Text Articles in Physics

Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’Ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski Dec 2016

Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’Ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski

Chemistry Publications

We use high resolution angle resolved photoemission spectroscopy and density functional theory with measured crystal structure parameters to study the electronic properties of CaKFe4As4. In contrast to the related CaFe2As2 compounds, CaKFe4As4 has a high Tc of 35 K at stochiometric composition. This presents a unique opportunity to study the properties of high temperature superconductivity in the iron arsenides in the absence of doping or substitution. The Fermi surface consists of several hole and electron pockets that have a range of diameters. We find that the values of the superconducting gap are nearly isotropic (within the explored portions of the ...


Measurements Of Double-Helicity Asymmetries In Inclusive J/Psi Production In Longitudinally Polarized P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole Apadula, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Dec 2016

Measurements Of Double-Helicity Asymmetries In Inclusive J/Psi Production In Longitudinally Polarized P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole Apadula, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We report the double-helicity asymmetry, A(LL)(J/Psi), in inclusive J/Psi production at forward rapidity as a function of transverse momentum p(T) and rapidity |y|. The data analyzed were taken during root s = 510 GeV longitudinally polarized p + p collisions at the Relativistic Heavy Ion Collider in the 2013 run using the PHENIX detector. At this collision energy, J/Psi particles are predominantly produced through gluon-gluon scatterings, thus A(LL)(J/Psi) is sensitive to the gluon polarization inside the proton. We measured A(LL)(J/Psi) by detecting the decay daughter muon pairs mu(+)mu(-) within ...


Mode-Sum Prescription For The Vacuum Polarization In Odd Dimensions, Peter Taylor, Cormac Breen Dec 2016

Mode-Sum Prescription For The Vacuum Polarization In Odd Dimensions, Peter Taylor, Cormac Breen

Articles

We present a new mode-sum regularization prescription for computing the vacuum polarization of a scalar field in static spherically-symmetric black hole spacetimes in odd dimensions. This is the first general and systematic approach to regularized vacuum polarization in higher dimensions. Remarkably, the regularization parameters can be computed in closed form in arbitrary dimensions and for arbitrary metric function $f(r)$. In fact, we show that in spite of the increasing severity and number of the divergences to be regularized, the method presented is mostly agnostic to the number of dimensions. Finally, as an explicit example of our method, we show ...


Probing Quantumness With Joint Continuous Measurements Of Non-Commuting Observables, Luis Pedro García-Pintos, Justin Dressel Dec 2016

Probing Quantumness With Joint Continuous Measurements Of Non-Commuting Observables, Luis Pedro García-Pintos, Justin Dressel

Mathematics, Physics, and Computer Science Faculty Articles and Research

We analyze the continuous measurement of two noncommuting observables for a qubit, and investigate whether the simultaneously observed noisy signals are consistent with the evolution of an equivalent classical system. Following the approach outlined by Leggett and Garg, we show that the readouts violate macrorealistic inequalities for arbitrarily short temporal correlations. Moreover, the derived inequalities are manifestly violated even in the absence of Hamiltonian evolution, unlike for Leggett-Garg inequalities that use a single continuous measurement. Such a violation should indicate the failure of at least one postulate of macrorealism: either physical quantities do not have well-defined values at all times ...


Advanced Dual Beam Optical Tweezers For Undergraduate Biophysics Research, Brian Daudelin Dec 2016

Advanced Dual Beam Optical Tweezers For Undergraduate Biophysics Research, Brian Daudelin

Honors Program Theses and Projects

Optical tweezing is a modern physics technique which allows us to use the radiation pressure provided from laser beams to trap very small microscopic particles. In the last two decades optical tweezers have been used extensively in biophysics and atomic physics to study the building blocks of our world on the cellular and quantum levels. Our goal is to construct a dual beam optical tweezers for future undergraduate biophysical research. In this thesis we discuss how the construction and assembly of the dual beam optical tweezers is done from start to finish. Construction consisted of assembling a polarization maintaining laser ...


Quantifying The Dna Binding Properties Of The Binuclear Ruthenium Complex Λλ-P, Nicholas Bryden Dec 2016

Quantifying The Dna Binding Properties Of The Binuclear Ruthenium Complex Λλ-P, Nicholas Bryden

Honors Program Theses and Projects

Threading intercalators are small molecules that bind to DNA by threading their side chains through the DNA bases to intercalate their middle planar section between the DNA base pairs. The high binding affinity and slow dissociation rates of threading intercalators have put them in the class of prospective anti-cancer drugs. In this study we explore the binding of a specific threading intercalator, a binuclear ruthenium complex ΛΛ-P (ΛΛ-[μ-bidppz(phen)4Ru2]4+) using optical tweezers. A single DNA molecule is held at a constant force and the small molecules are introduced to the system in various concentrations until equilibrium is ...


Generation Of Flower High-Order Poincaré Sphere Laser Beams From A Spatial Light Modulator, T. H. Lu, T. D. Huang, J. G. Wang, L. W. Wang, Robert R. Alfano Dec 2016

Generation Of Flower High-Order Poincaré Sphere Laser Beams From A Spatial Light Modulator, T. H. Lu, T. D. Huang, J. G. Wang, L. W. Wang, Robert R. Alfano

Publications and Research

We propose and experimentally demonstrate a new complex laser beam with inhomogeneous polarization distributions mapping onto high-order Poincaré spheres (HOPSs). The complex laser mode is achieved by superposition of Laguerre-Gaussian modes and manifests exotic flower-like localization on intensity and phase profiles. A simple optical system is used to generate a polarization-variant distribution on the complex laser mode by superposition of orthogonal circular polarizations with opposite topological charges. Numerical analyses of the polarization distribution are consistent with the experimental results. The novel flower HOPS beams can act as a new light source for photonic applications.


Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown Dec 2016

Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown

Publications

The recent analytical of multi-layer analyses proposed by Sajjadi et al. (J Eng Math 84:73, 2014) (SHD14 therein) is solved numerically for atmospheric turbulent shear flows blowing over growing (or unsteady) Stokes (bimodal) water waves, of low-to-moderate steepness. For unsteady surface waves, the amplitude a(t)∝ekcita(t)∝ekcit, where kcikci is the wave growth factor, k is the wavenumber, and cici is the complex part of the wave phase speed, and thus, the waves begin to grow as more energy is transferred to them by the wind. This will then display the critical height to a point, where ...


Rheology Of Sediment Transported By A Laminar Flow, Morgane Houssais, Carlos P. Ortiz, Douglas J. Durian, Douglas J. Jerolmack Dec 2016

Rheology Of Sediment Transported By A Laminar Flow, Morgane Houssais, Carlos P. Ortiz, Douglas J. Durian, Douglas J. Jerolmack

Department of Physics Papers

Understanding the dynamics of fluid-driven sediment transport remains challenging, as it occurs at the interface between a granular material and a fluid flow. Boyer, Guazzelli, and Pouliquen [Phys. Rev. Lett.107, 188301 (2011)] proposed a local rheology unifying dense dry-granular and viscous-suspension flows, but it has been validated only for neutrally buoyant particles in a confined and homogeneous system. Here we generalize the Boyer, Guazzelli, and Pouliquen model to account for the weight of a particle by addition of a pressure P0 and test the ability of this model to describe sediment transport in an idealized laboratory river. We ...


Effect Of Disorder On The Magnetic And Electronic Structure Of A Prospective Spin-Gapless Semiconductor Mncrval, P. Kharel, J. Herran, Pavel Lukashev, Y. Jin, J. Waybright, S. Gilbert, B, Staten, P. Gray, S. Valloppilly, Y. Huh, D. J. Sellmyer Dec 2016

Effect Of Disorder On The Magnetic And Electronic Structure Of A Prospective Spin-Gapless Semiconductor Mncrval, P. Kharel, J. Herran, Pavel Lukashev, Y. Jin, J. Waybright, S. Gilbert, B, Staten, P. Gray, S. Valloppilly, Y. Huh, D. J. Sellmyer

Faculty Publications

Recent discovery of a new class of materials, spin-gapless semiconductors (SGS), has attracted considerable attention in the last few years, primarily due to potential applications in the emerging field of spin-based electronics (spintronics). Here, we investigate structural, electronic, and magnetic properties of one potential SGS compound, MnCrVAl, using various experimental and theoretical techniques. Our calculations show that this material exhibits ≈ 0.5 eV band gap for the majority-spin states, while for the minority-spin it is nearly gapless. The calculated magnetic moment for the completely ordered structure is 2.9 µB/f.u., which is different from our experimentally measured ...


Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan Dec 2016

Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan

Physics and Astronomy Faculty Publications

Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii. We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green ...


Point Island Models For Nucleation And Growth Of Supported Nanoclusters During Surface Deposition, Yong Han, Émilie Gaudry, Tiago J. Oliveira, James W. Evans Dec 2016

Point Island Models For Nucleation And Growth Of Supported Nanoclusters During Surface Deposition, Yong Han, Émilie Gaudry, Tiago J. Oliveira, James W. Evans

Physics and Astronomy Publications

Point island models (PIMs) are presented for the formation of supported nanoclusters (or islands) during deposition on flat crystalline substrates at lower submonolayer coverages. These models treat islands as occupying a single adsorption site, although carrying a label to track their size (i.e., they suppress island structure). However, they are particularly effective in describing the island size and spatial distributions. In fact, these PIMs provide fundamental insight into the key features for homogeneous nucleation and growth processes on surfaces. PIMs are also versatile being readily adapted to treat both diffusion-limited and attachment-limited growth and also a variety of other ...


Capture Zone Area Distributions For Nucleation And Growth Of Islands During Submonolayer Deposition, Yong Han, Maozhi Li, James W. Evans Dec 2016

Capture Zone Area Distributions For Nucleation And Growth Of Islands During Submonolayer Deposition, Yong Han, Maozhi Li, James W. Evans

Physics and Astronomy Publications

A fundamental evolution equation is developed to describe the distribution of areas of capture zones (CZs) associated with islands formed by homogeneous nucleation and growth during submonolayer deposition on perfect flat surfaces. This equation involves various quantities which characterize subtle spatial aspects of the nucleation process. These quantities in turn depend on the complex stochastic geometry of the CZ tessellation of the surface, and their detailed form determines the CZ area distribution (CZD) including its asymptotic features. For small CZ areas, behavior of the CZD reflects the critical island size, i. For large CZ areas, it may reflect the probability ...


Adsorption Of Dysprosium On The Graphite (0001) Surface: Nucleation And Growth At 300 K, Emma J. Kwolek, Huaping Lei, Ann Lii-Rosales, Mark Wallingford, Yinghui Zhou, Cai-Zhuang Wang, Michael C. Tringides, James W. Evans Dec 2016

Adsorption Of Dysprosium On The Graphite (0001) Surface: Nucleation And Growth At 300 K, Emma J. Kwolek, Huaping Lei, Ann Lii-Rosales, Mark Wallingford, Yinghui Zhou, Cai-Zhuang Wang, Michael C. Tringides, James W. Evans

Physics and Astronomy Publications

We have studied nucleation and growth of Dy islands on the basal plane of graphite at 300 K using scanning tunneling microscopy, density functional theory (DFT) in a form that includes van der Waals interactions, and analytic theory. The interaction of atomic Dy with graphite is strong, while the diffusion barrier is small. Experiment shows that at 300 K, the density of nucleated islands is close to the value predicted for homogeneous nucleation, using critical nucleus size of 1 and the DFT-derived diffusion barrier. Homogeneous nucleation is also supported by the monomodal shape of the island size distributions. Comparison with ...


Linear Feedback Stabilization For A Continuously Monitored Qubit, Taylor Lee Patti, A. Chantasri, Justin Dressel, A. N. Jordan Dec 2016

Linear Feedback Stabilization For A Continuously Monitored Qubit, Taylor Lee Patti, A. Chantasri, Justin Dressel, A. N. Jordan

Student Scholar Symposium Abstracts and Posters

In quantum mechanics, standard or strong measurement approaches generally result in the collapse of an ensemble of wavefunctions into a stochastic mixture of eigenstates. On the other hand, continuous or weak measurements have the propensity to dynamically control the evolution of quantum states over time, guiding the trajectory of the state into non-trivial superpositions and maintaining state purity. This kind of measurement-induced state steering is of great theoretical and experimental interest for the harnessing of quantum bits or "qubits", which are the fundamental unit of the emerging quantum computer. We explore continuous measurement-based quantum state stabilization through linear feedback control ...


Azimuthally Anisotropic Emission Of Low-Momentum Direct Photons In Au Plus Au Collisions At Root S-Nn=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Alexey Yu. Semenov, Abhisek Sen, M. Shimomura, C. L. Silva, Arbin Timilsina, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Dec 2016

Azimuthally Anisotropic Emission Of Low-Momentum Direct Photons In Au Plus Au Collisions At Root S-Nn=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Alexey Yu. Semenov, Abhisek Sen, M. Shimomura, C. L. Silva, Arbin Timilsina, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider has measured second- and third-order Fourier coefficients of the azimuthal distributions of direct photons emitted at midrapidity in Au + Au collisions at root S-NN = 200 GeV for various collision centralities. Combining two different analysis techniques, results were obtained in the transverse momentum range of 0.4 < p(T) < 4.0 GeV/c. At low p(T) the second-order coefficients, nu(2), are similar to the ones observed in hadrons. Third-order coefficients, nu(3), are nonzero and almost independent of centrality. These new results on nu(2) and nu(3), combined with previously published results on yields, are compared to model calculations that provide yields and asymmetries in the same framework. Those models are challenged to explain simultaneously the observed large yield and large azimuthal anisotropies.


Use Of Solid N2 Surfaces In Metastable Particle Detection, Wladyslaw Kedzierski, J. W. Mcconkey Dec 2016

Use Of Solid N2 Surfaces In Metastable Particle Detection, Wladyslaw Kedzierski, J. W. Mcconkey

Physics Publications

A novel detector is described in which solid nitrogen at 17 K is used as the most significant element. Metastable particles impinge on this element and immediately transfer their internal energy to the solid nitrogen producing photons, via excimer formation or otherwise, whose wavelength depends on the metastable being detected and the energy transfer process. The performance of the instrument for the detection of atomic oxygen and molecular nitrogen metastables is discussed.


Evolution And Rationale For United States Department Of Defense Electromagnetic Pulse Protection Standard, George H. Baker Iii Dec 2016

Evolution And Rationale For United States Department Of Defense Electromagnetic Pulse Protection Standard, George H. Baker Iii

Department of Integrated Science and Technology - Faculty Scholarship

The United States (US) Department of Defense (DoD) Electromagnetic Pulse (EMP) protection standard offers a solid basis for protecting commercial communication, data, and control facilities. Because of the standard’s shielded barrier and test requirements, it is not surprising that there is a strong temptation within industry and government to dismiss the MIL-STD 188-125 approach in favor of less rigorous protection methods. It is important to understand that US DoD EMP protection standard for fixed facilities, MIL-STD-188-125, reflects an evolution by trial and error that spanned a period of decades beginning with the acquisition of the Minuteman Missile System in ...


A Study Of The Bacteriological Quality Of Roof-Harvested Rainwater And An Evaluation Of Sodis As A Suitable Treatment Technology In Rural Sub-Saharan Africa, R Nalwanga, C K. Muyanja, Kevin G. Mcguigan, B Quilty Dec 2016

A Study Of The Bacteriological Quality Of Roof-Harvested Rainwater And An Evaluation Of Sodis As A Suitable Treatment Technology In Rural Sub-Saharan Africa, R Nalwanga, C K. Muyanja, Kevin G. Mcguigan, B Quilty

Physiology and Medical Physics Articles

Harvested rainwater (HRW) is of great socio-economic importance particularly in areas where water sources are scarce or polluted. This case study was carried out in a rural area of Southern Uganda where the community has limited access to safe drinking water. The aims of the project were to investigate the quality of harvested rainwater over a year long period covering wet and dry seasons and to investigate the use of solar waterdisinfection (SODIS) as a water treatment technology. Fifty households using roof HRW were selected. The systems used included catchment ponds, metallic, concrete and plastic tanks. All households used the ...


Dielectric Analysis Of Aqueous Poly(L-Glutamic Acid) And Poly-L-(Glutamic Acid4, Tyrosine1) Solutions At High Frequencies From Capacitance Measurements, Jorge Monreal, Tatiana Eggers, Manh-Huong Phan Dec 2016

Dielectric Analysis Of Aqueous Poly(L-Glutamic Acid) And Poly-L-(Glutamic Acid4, Tyrosine1) Solutions At High Frequencies From Capacitance Measurements, Jorge Monreal, Tatiana Eggers, Manh-Huong Phan

Physics Faculty Publications

A new parallel-plate capacitor fixture has been designed and successfully used to measure dielectric loss of polyelectrolyte solutions with volumes as low as droplets of 13–26 μL. It is particularly useful when studying polypeptides that are either high-cost or can be synthesized only in limited quantities. The ease with which the fixture can be used to obtain preliminary dielectric loss data yields savings in time and cost. In this study capacitance measurements were performed in a wide range of frequencies between 1 and 800 MHz using an Agilent 4191RF Impedance Analyzer. Accuracy of measurements was carefully examined through a ...


Transport And Optical Conductivity In The Hubbard Model: A High-Temperature Expansion Perspective, Edward Perepelitsky, Andrew Galatas, Jernej Mravlje, Rok Žitko, Ehsan Khatami, B. Shastry, Antoine Georges Dec 2016

Transport And Optical Conductivity In The Hubbard Model: A High-Temperature Expansion Perspective, Edward Perepelitsky, Andrew Galatas, Jernej Mravlje, Rok Žitko, Ehsan Khatami, B. Shastry, Antoine Georges

Faculty Publications

We derive analytical expressions for the spectral moments of the dynamical response functions of the Hubbard model using the high-temperature series expansion. We consider generic dimension d as well as the infinite-d limit, arbitrary electron density n, and both finite and infinite repulsion U. We use moment-reconstruction methods to obtain the one-electron spectral function, the self-energy, and the optical conductivity. They are all smooth functions at high temperature and, at large U, they are featureless with characteristic widths of the order of the lattice hopping parameter t. In the infinite-d limit, we compare the series expansion results with accurate numerical ...


Spontaneous Topological Transitions Of Electromagnetic Fields In Spatially Inhomogeneous Cp-Odd Domains, Kirill Tuchin Dec 2016

Spontaneous Topological Transitions Of Electromagnetic Fields In Spatially Inhomogeneous Cp-Odd Domains, Kirill Tuchin

Physics and Astronomy Publications

Metastable CP-odd domains of the hot QCD matter are coupled to QED via the chiral anomaly. The topology of electromagnetic field in these domains is characterized by magnetic helicity. It is argued, using the Maxwell-Chern-Simons model, that spatial inhomogeneity of the domains induces spontaneous transitions of electromagnetic field between the opposite magnetic helicity states.


Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell Dec 2016

Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell

Physics Faculty Publications

Large introductory science courses are isolating for many students, and reducing this isolation is an important factor for student retention in college. Active learning courses often build community among students as an explicit goal, but many commuter or non-traditional students have limited on-campus time. Online discussion forums provide one tool for engaging students with each other outside of class time. This study uses social network analysis with forum data from an introductory physics course to examine students' positions in the class discussion network and link it to their final course grades. We find that, contrary to expectations, there is no ...


A Laboratory Facility To Study Gas-Aerosol-Cloud Interactions In A Turbulent Environment: The Π Chamber, K. Chang, J. Bench, M. Brege, Will Cantrell, K. Chandrakar, David Ciochetto, Claudio Mazzoleni, Lynn Mazzoleni, Dennis Niedermeier, R. A. Shaw Dec 2016

A Laboratory Facility To Study Gas-Aerosol-Cloud Interactions In A Turbulent Environment: The Π Chamber, K. Chang, J. Bench, M. Brege, Will Cantrell, K. Chandrakar, David Ciochetto, Claudio Mazzoleni, Lynn Mazzoleni, Dennis Niedermeier, R. A. Shaw

Department of Physics Publications

A detailed understanding of interactions of aerosols, cloud droplets/ice crystals, and trace gases within the atmosphere is of prime importance for an accurate understanding of Earth’s weather and climate. One aspect that remains especially vexing is that clouds are ubiquitously turbulent, and therefore thermodynamic and compositional variables, such as water vapor supersaturation, fluctuate in space and time. With these problems in mind, a multiphase, turbulent reaction chamber—called the Π chamber because of the internal volume of 3.14 m3 with the cylindrical insert installed—has been developed. It is capable of pressures ranging from 1,000 ...


Plasma Processes And Polymers Third Special Issue On Plasma And Cancer, Mounir Laroussi, Annemie Bogaerts, Nazir Barekzi Dec 2016

Plasma Processes And Polymers Third Special Issue On Plasma And Cancer, Mounir Laroussi, Annemie Bogaerts, Nazir Barekzi

Electrical & Computer Engineering Faculty Publications

(First paragraph) This issue of Plasma Processes and Polymers is the third in a series on the applications of low temperature plasma (LTP) against cancer, or “plasma oncology.” The papers in this issue are inspired from the talks given at the third International Workshop on Plasma for Cancer Treatment (IWPCT) which took place on April 11–12, 2016 in Washington, DC, USA. IWPCT is an international workshop that was created in 2014 as a venue to share cutting edge plasma oncology research. The first IWPCT was held in Washington DC, under the co-chairmanship of Prof. Mounir Laroussi (Old Dominion University ...


High Order Harmonic Generation From Sf₆: Deconvolution Of Macroscopic Effects, B. P. Wilson, K. D. Fulfer, S. Mondal, X. Ren, J. Tross, E. D. Poliakoff, J. Jose, Anh-Thu Le, R. R. Lucchese, Carlos A. Trallero-Herrero Dec 2016

High Order Harmonic Generation From Sf₆: Deconvolution Of Macroscopic Effects, B. P. Wilson, K. D. Fulfer, S. Mondal, X. Ren, J. Tross, E. D. Poliakoff, J. Jose, Anh-Thu Le, R. R. Lucchese, Carlos A. Trallero-Herrero

Physics Faculty Research & Creative Works

We measure high order harmonics from the molecule SF₆ over a large range of phase matching conditions and observe several features in the harmonics that are largely independent of such macroscopic conditions. The experimental data are then compared to the quantitative rescattering theory for the generation of harmonics from three orbitals. With this comparison, we are able to assign spectroscopic features in the harmonics to contributions from 1t1g (HOMO) and 5t1u (HOMO-1) orbitals.


Prospects For Observing And Localizing Gravitational-Wave Transients With Advanced Ligo And Advanced Virgo, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2016

Prospects For Observing And Localizing Gravitational-Wave Transients With Advanced Ligo And Advanced Virgo, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present a possible observing scenario for the Advanced LIGO and Advanced Virgo gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We determine the expected sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron-star systems, which are considered the most promising for multi-messenger astronomy. The ability to localize the sources ...


Phase Field Simulations Of Plastic Strain-Induced Phase Transformations Under High Pressure And Large Shear, Mahdi Javanbakht, Valery I. Levitas Dec 2016

Phase Field Simulations Of Plastic Strain-Induced Phase Transformations Under High Pressure And Large Shear, Mahdi Javanbakht, Valery I. Levitas

Aerospace Engineering Publications

Pressure and shear strain-induced phase transformations (PTs) in a nanograined bicrystal at the evolving dislocations pile-up have been studied utilizing a phase field approach (PFA). The complete system of PFA equations for coupled martensitic PT, dislocation evolution, and mechanics at large strains is presented and solved using the finite element method (FEM). The nucleation pressure for the high-pressure phase (HPP) under hydrostatic conditions near a single dislocation was determined to be 15.9 GPa. Under shear, a dislocation pile-up that appears in the left grain creates strong stress concentration near its tip and significantly increases the local thermodynamic driving force ...


Emergence And Analysis Of Kuramoto-Sakaguchi-Like Models As An Effective Description For The Dynamics Of Coupled Wien-Bridge Oscillators, Lars Q. English, David Mertens, Saidou Abdoulkary, Christopher B. Fritz, Kevin Skowronski, P.G. Kevrekidis Dec 2016

Emergence And Analysis Of Kuramoto-Sakaguchi-Like Models As An Effective Description For The Dynamics Of Coupled Wien-Bridge Oscillators, Lars Q. English, David Mertens, Saidou Abdoulkary, Christopher B. Fritz, Kevin Skowronski, P.G. Kevrekidis

Faculty and Staff Publications By Year

We derive the Kuramoto-Sakaguchi model from the basic circuit equations governing two coupled Wien-bridge oscillators. A Wien-bridge oscillator is a particular realization of a tunable autonomous oscillator that makes use of frequency filtering (via an RC bandpass filter) and positive feedback (via an operational amplifier). In the past few years, such oscillators have started to be utilized in synchronization studies. We first show that the Wien-bridge circuit equations can be cast in the form of a coupled pair of van der Pol equations. Subsequently, by applying the method of multiple time scales, we derive the differential equations that govern the ...


Observation And Analysis Of Ordered And Disordered Structures On The Zno(0001) Polar Surface, Hu Xu, Lei Dong, Xingqiang Shi, Yang Liu, Michel A. Van Hove, Nian Lin, S. Y. Tong Dec 2016

Observation And Analysis Of Ordered And Disordered Structures On The Zno(0001) Polar Surface, Hu Xu, Lei Dong, Xingqiang Shi, Yang Liu, Michel A. Van Hove, Nian Lin, S. Y. Tong

HKBU Staff Publication

Using low temperature scanning tunneling microscopy (STM), we discovered locally ordered patches of O adatoms and single Zn vacancies on the Zn-terminated ZnO(0001) polar surface. Such patches are determined to be metastable ordered structures on the surface. Density functional theory (DFT) calculations show that Zn atoms bonded to an O adatom encounter a larger reaction barrier for leaving lattice sites, explaining the observed general disordered nature of the Zn-terminated surface that is populated by cavities of different shapes and sizes and disordered distribution of adatoms. The interplay among different driving mechanisms provides valuable insight as to how a polar ...