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2013

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Articles 481 - 510 of 1248

Full-Text Articles in Physics

Energy Flux Streamlines Versus Acoustic Rays For Modeling Interaction With Rigid Boundaries: Near Field Of Sound From A Circular Loudspeaker, Cleon Dean, James P. Braselton Jun 2013

Energy Flux Streamlines Versus Acoustic Rays For Modeling Interaction With Rigid Boundaries: Near Field Of Sound From A Circular Loudspeaker, Cleon Dean, James P. Braselton

Physics & Astronomy: Faculty Publications

Sound emitted by a circular loudspeaker can be treated as equivalent to a plane wave diffracted by a circular aperture in a rigid, sound absorbing screen. Axial symmetry leads one to expect constructive interference along the symmetry axis in the near field (the Poisson-Arago spot). An energy flux streamline model was developed to help visualize this and other features of the nearsound field. The model is used to draw out similarities and differences between energy flux streamlines and acoustic rays, particularly in the transition to the far field. © 2013 Acoustical Society of America

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Hilbert Space Theory And Applications In Basic Quantum Mechanics, Matthew Gagne Jun 2013

Hilbert Space Theory And Applications In Basic Quantum Mechanics, Matthew Gagne

Mathematics

We explore the basic mathematical physics of quantum mechanics. Our primary focus will be on Hilbert space theory and applications as well as the theory of linear operators on Hilbert space. We show how Hermitian operators are used to represent quantum observables and investigate the spectrum of various linear operators. We discuss deviation and uncertainty and briefly suggest how symmetry and representations are involved in quantum theory.

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Ramjet Combustion Chamber, Paul Cameron Stone Jun 2013

Ramjet Combustion Chamber, Paul Cameron Stone

Aerospace Engineering

A ramjet combustion chamber is designed and some initial assembly fabrication and test completed as a component of a ramjet graduate project for California Polytechnic State University, San Luis Obispo Supersonic Wind Tunnel. The combustor design is driven by a theoretical model created by a Cal Poly graduate student, Harrison Sykes. Temperature, pressure, and fuel flow will be measured.

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A Rigid, Thermally-Isolating Suspension For An Adr, Ruslan Hummatov, Linh N. Le, Felix T. Jaeckel, S. T. P. Boyd Jun 2013

A Rigid, Thermally-Isolating Suspension For An Adr, Ruslan Hummatov, Linh N. Le, Felix T. Jaeckel, S. T. P. Boyd

Physics & Astronomy Faculty and Staff Publications

We have recently developed a scanning optical pulser for the precise measurement of device-to-device reproducibility, position-dependent response, and other important characteristics of low-temperature particle detectors. By making maps of the reflected light, we can measure the position of the detectors (mounted on the ADR) under the scanner (mounted on the 3K flange) to micro-meter precision . We find that the detector position typically changes approximately 3-4 μm from ADR regeneration to ADR regeneration . Further, when the ADR is allowed to warm at zero field over many hours from its base temperature to approximately 1 K, an additional change in …

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Characterisation Of Core@Shell Nanoparticles Using Advanced Electron Microscopy, Andrew Wheatley Jun 2013

Characterisation Of Core@Shell Nanoparticles Using Advanced Electron Microscopy, Andrew Wheatley

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2013)

No abstract provided.

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Cluster Approach To The Electronic Properties Modeling Of Nanocrystal Structures, Malgorzata Makowska-Janusik, Nathalie Herlin-Boime, Johann Boucle, Abdel Hadi Kassiba Jun 2013

Cluster Approach To The Electronic Properties Modeling Of Nanocrystal Structures, Malgorzata Makowska-Janusik, Nathalie Herlin-Boime, Johann Boucle, Abdel Hadi Kassiba

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2013)

No abstract provided.

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On The Catalyst-Free Fabrication Of Carbon Nanotubes And Graphene, Mark Ruemmeli Jun 2013

On The Catalyst-Free Fabrication Of Carbon Nanotubes And Graphene, Mark Ruemmeli

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2013)

No abstract provided.

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Nano-Objects And Nanochemistry By Selective Atom Diffusion At Advanced Semiconductor Surfaces & Interfaces, Patrick Soukiassian Jun 2013

Nano-Objects And Nanochemistry By Selective Atom Diffusion At Advanced Semiconductor Surfaces & Interfaces, Patrick Soukiassian

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2013)

No abstract provided.

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Tilt Angle And Birefringence Of Smectic Liquid Crystal Materials, Taylor Van Winkle Jun 2013

Tilt Angle And Birefringence Of Smectic Liquid Crystal Materials, Taylor Van Winkle

Physics

No abstract provided.

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Photo-Electro-Magnetic Or Photo-Thermo-Magneto-Electric Effects In Graphene?, Marian Nowak, Gregory Kozlowski, B. Solecka, M. Jesionek Jun 2013

Photo-Electro-Magnetic Or Photo-Thermo-Magneto-Electric Effects In Graphene?, Marian Nowak, Gregory Kozlowski, B. Solecka, M. Jesionek

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2013)

No abstract provided.

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Continuous Development Of Schemes For Parallel Computing Of The Electrostatics In Biological Systems: Implementation In Delphi, Chuan Li, Marharyta Petukh, Lin Li, Emil Alexov Jun 2013

Continuous Development Of Schemes For Parallel Computing Of The Electrostatics In Biological Systems: Implementation In Delphi, Chuan Li, Marharyta Petukh, Lin Li, Emil Alexov

Publications

Due to the enormous importance of electrostatics in molecular biology, calculating the electrostatic potential and corresponding energies has become a standard computational approach for the study of biomolecules and nano-objects immersed in water and salt phase or other media. However, the electrostatics of large macromolecules and macromolecular complexes, including nano-objects, may not be obtainable via explicit methods and even the standard continuum electrostatics methods may not be applicable due to high computational time and memory requirements. Here, we report further development of the parallelization scheme reported in our previous work (J Comput Chem. 2012 Sep 15; 33(24):1960–6.) to include parallelization …

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Cancer Missense Mutations Alter Binding Properties Of Proteins And Their Interaction Networks, Hafumi Nisha, Manoj Tyagi, Shaolei Teng, Benjamin A. Shoemaker, Kosuke Hashimoto, Emil Alexov, Stefan Wuchty, Anna R. Panchenko Jun 2013

Cancer Missense Mutations Alter Binding Properties Of Proteins And Their Interaction Networks, Hafumi Nisha, Manoj Tyagi, Shaolei Teng, Benjamin A. Shoemaker, Kosuke Hashimoto, Emil Alexov, Stefan Wuchty, Anna R. Panchenko

Publications

Many studies have shown that missense mutations might play an important role in carcinogenesis. However, the extent to which cancer mutations might affect biomolecular interactions remains unclear. Here, we map glioblastoma missense mutations on the human protein interactome, model the structures of affected protein complexes and decipher the effect of mutations on protein-protein, protein-nucleic acid and protein-ion binding interfaces. Although some missense mutations over-stabilize protein complexes, we found that the overall effect of mutations is destabilizing, mostly affecting the electrostatic component of binding energy. We also showed that mutations on interfaces resulted in more drastic changes of amino acid physico-chemical …

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Marine Low Cloud Sensitivity To An Idealized Climate Change: The Cgils Les Intercomparison, Peter N. Blossey, Christopher S. Bretherton, Minghua Zhang, Anning Cheng, Satoshi Endo, Thijs Heus, Yangang Liu, Adrian P. Lock, Stephan R. De Roode, Kuan Man Xu Jun 2013

Marine Low Cloud Sensitivity To An Idealized Climate Change: The Cgils Les Intercomparison, Peter N. Blossey, Christopher S. Bretherton, Minghua Zhang, Anning Cheng, Satoshi Endo, Thijs Heus, Yangang Liu, Adrian P. Lock, Stephan R. De Roode, Kuan Man Xu

Physics Faculty Publications

Subtropical marine low cloud sensitivity to an idealized climate change is compared in six large-eddy simulation (LES) models as part of CGILS. July cloud cover is simulated at three locations over the subtropical northeast Pacific Ocean, which are typified by cold sea surface temperatures (SSTs) under well-mixed stratocumulus, cool SSTs under decoupled stratocumulus, and shallow cumulus clouds overlying warmer SSTs. The idealized climate change includes a uniform 2 K SST increase with corresponding moist-adiabatic warming aloft and subsidence changes, but no change in free-tropospheric relative humidity, surface wind speed, or CO2. For each case, realistic advective forcings and boundary conditions …

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Effects Of Extraneous Surface Charges On The Enhanced Raman Scattering From Metallic Nanoparticles, H. Y. Chung, P. T. Leung, D. P. Tsai Jun 2013

Effects Of Extraneous Surface Charges On The Enhanced Raman Scattering From Metallic Nanoparticles, H. Y. Chung, P. T. Leung, D. P. Tsai

Physics Faculty Publications and Presentations

Motivating by recent experiments on surface enhanced Raman scattering (SERS) from colloidal solutions, we present here a simple model to elucidate the effects of extraneous surface charges on the enhanced Raman signal. The model is based on the well-established Gersten-Nitzan model coupled to the modified Mie scattering theory of Bohren and Hunt in the long wavelength approximation. We further introduce corrections from the modified long wavelength approximation to the Gersten-Nitzan model for the improvement of its accuracy. Our results show that the surface charge will generally lead to a blueshift in the resonance frequency and greater enhancements in the SERS …

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Entropy Driven Crystal Formation On Highly Strained Substrates, John R. Savage, Stefan F. Hopp, Rajesh Ganapathy, Sharon J. Gerbode, Andreas Heuer, Itai Cohen Jun 2013

Entropy Driven Crystal Formation On Highly Strained Substrates, John R. Savage, Stefan F. Hopp, Rajesh Ganapathy, Sharon J. Gerbode, Andreas Heuer, Itai Cohen

All HMC Faculty Publications and Research

In heteroepitaxy, lattice mismatch between the deposited material and the underlying surface strongly affects nucleation and growth processes. The effect of mismatch is well studied in atoms with growth kinetics typically dominated by bond formation with interaction lengths on the order of one lattice spacing. In contrast, less is understood about how mismatch affects crystallization of larger particles, such as globular proteins and nanoparticles, where interparticle interaction energies are often comparable to thermal fluctuations and are short ranged, extending only a fraction of the particle size. Here, using colloidal experiments and simulations, we find particles with short-range attractive interactions form …

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Nanodielectric Properties Of High Conductivity Carbon-Loaded Polyimide Under Electron-Beam Irradiation, Amberly Evans, J. R. Dennison, Gregory Wilson, Justin Dekany Jun 2013

Nanodielectric Properties Of High Conductivity Carbon-Loaded Polyimide Under Electron-Beam Irradiation, Amberly Evans, J. R. Dennison, Gregory Wilson, Justin Dekany

Posters

Electron irradiation experiments were conducted to investigate the electron transport, charging, discharging, cathodoluminescence and emission properties of high-conductivity carbon-loaded polyimide (Black KaptonTM). We discuss how these results are related to the nanoscale structure of the composite material. Measurements were conducted in an ultrahigh vacuum electron emission test chamber from <40 K to 290 K, using a monoenergetic beam with energies ranging from 3 keV to 25 keV and flux densities from 0.1 nA/cm2 to 100 nA/cm2 to deposit electrons in the material surface layer. Various experiments measured transport and displacement currents to a rear grounded electrode, absolute electron emission yields, absolute electron-induced photon emission yields and photon emission spectra (~250 nm to 1700 nm), and arcing rates and location. Numerous …

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An Inexpensive Scheffler Reflector For Developing Nations, Mike Kim Jun 2013

An Inexpensive Scheffler Reflector For Developing Nations, Mike Kim

Physics

Scheffler reflectors are an appropriate solar technology used to provide heat for cooking surfaces and has been adopted in many developing nations. The first Scheffler was built in North America in 2010 by Jason Rapp et al., taking a group of four students approximately $2000 and 3 months. Thus, our task was to minimize certain aspects of the Scheffler construction process, so that it would be more appropriate for developing countries and industrial applications alike. Additionally, this senior project aims to incorporate the thermal storage unit and tracking system, with the current Scheffler system, to render a workable cooking technology. …

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Development Without Energy? Assessing Future Scenarios Of Energy Consumption In Developing Countries, Jan Christof Steckel, Robert J. Brecha, Michael Jakob, Jessica Strefler, Gunnar Luderer Jun 2013

Development Without Energy? Assessing Future Scenarios Of Energy Consumption In Developing Countries, Jan Christof Steckel, Robert J. Brecha, Michael Jakob, Jessica Strefler, Gunnar Luderer

Physics Faculty Publications

We analyze the relationship between economic development and energy consumption in the context of greenhouse gas mitigation. The main contribution of this work is to compare estimates of energy thresholds in the form of minimum energy requirements to reach high levels of development with output projections of per capita final energy supply from a group of integrated assessment models (IAMs). Scenarios project that reductions of carbon emissions in developing countries will be achieved not only by means of decreasing the carbon intensity, but also by making a significant break with the historically observed relationship between energy use and economic growth. …

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A Dynamical (E,2e) Investigation Of The Structurally Related Cyclic Ethers Tetrahydrofuran, Tetrahydropyran, And 1,4-Dioxane, J. D. Builth-Williams, Susan M. Bellm, Luca Chiari, Penny A. Thorn, Darryl B. Jones, Hari Chaluvadi, Don H. Madison, Chuangang Ning, B. Lohmann, Gabriel Da Silva, Michael J. Brunger Jun 2013

A Dynamical (E,2e) Investigation Of The Structurally Related Cyclic Ethers Tetrahydrofuran, Tetrahydropyran, And 1,4-Dioxane, J. D. Builth-Williams, Susan M. Bellm, Luca Chiari, Penny A. Thorn, Darryl B. Jones, Hari Chaluvadi, Don H. Madison, Chuangang Ning, B. Lohmann, Gabriel Da Silva, Michael J. Brunger

Physics Faculty Research & Creative Works

Triple differential cross section measurements for the electron-impact ionization of the highest occupied molecular orbitals of tetrahydropyran and 1,4-dioxane are presented. For each molecule, experimental measurements were performed using the (e,2e) technique in asymmetric coplanar kinematics with an incident electron energy of 250 eV and an ejected electron energy of 20 eV. With the scattered electrons being detected at -5°, the angular distributions of the ejected electrons in the binary and recoil regions were observed. These measurements are compared with calculations performed within the molecular 3-body distorted wave model. Here, reasonable agreement was observed between the theoretical model and the …

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Erratum: Gravitationally Coupled Dirac Equation For Antimatter (Physical Review A (2013) 87 (032101) Doi:10.1103/Physreva.87.032101), Ulrich D. Jentschura Jun 2013

Erratum: Gravitationally Coupled Dirac Equation For Antimatter (Physical Review A (2013) 87 (032101) Doi:10.1103/Physreva.87.032101), Ulrich D. Jentschura

Physics Faculty Research & Creative Works

No abstract provided.

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Observation Of A New Boson With Mass Near 125 Gev In Pp Collisions At √S= 7 And 8 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva Jun 2013

Observation Of A New Boson With Mass Near 125 Gev In Pp Collisions At √S= 7 And 8 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A detailed description is reported of the analysis used by the CMS Collaboration in the search for the standard model Higgs boson in pp collisions at the LHC, which led to the observation of a new boson. The data sample corresponds to integrated luminosities up to 5.1 fb−1 at √s = 7 TeV, and up to 5.3 fb−1 at √s = 8 TeV. The results for five Higgs boson decay modes γγ, ZZ, WW, ττ , and bb, which show a combined local significance of 5 standard deviations near 125 GeV, are reviewed. A fit to the invariant mass of …

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Searches For Long-Lived Charged Particles In Pp Collisions At S√ =7 And 8 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Francisco Yumiceva Jun 2013

Searches For Long-Lived Charged Particles In Pp Collisions At S√ =7 And 8 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Francisco Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Results of searches for heavy stable charged particles produced in pp collisions at s" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√� = 7 and 8 TeV are presented corresponding to an integrated luminosity of 5.0 fb−1 and 18.8 fb−1, respectively. Data collected with the CMS detector are used to study the momentum, energy deposition, and time-of-flight of signal candidates. Leptons with an electric charge between e/3 and 8e …

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Organic Polymer Solar Cells: The Effects Of Device Packaging On Cell Lifetime, Spencer Herrick Jun 2013

Organic Polymer Solar Cells: The Effects Of Device Packaging On Cell Lifetime, Spencer Herrick

Physics

As the earth runs out of nonrenewable energy sources and climate change starts to have drastic effects on the environment, the world is becoming increasingly desperate for cost efficient, renewable energy sources. Organic polymer based solar technology is a cutting edge approach to meeting the world’s energy demands. We fabricate single-layer, organic photovoltaics devices that utilize the electrical characteristics of semi-conductive polymers. These solution processable materials are beneficial due to their low material cost, lightweight, and simple fabrication requirements. Our devices utilize multiple photoactive polymers, P3HT and PCPDTBT, to absorb photons over a wide spectral range. We optimized various device …

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Dynamics Of The Fitzhugh-Nagumo Neuron Model, Zechariah Thurman Jun 2013

Dynamics Of The Fitzhugh-Nagumo Neuron Model, Zechariah Thurman

Physics

In this paper, the dynamical behavior of the Fitzhugh-Nagumo model is examined. The relationship between neuron input current and the firing frequency of the neuron is characterized. Various coupling schemes are also examined, and their effects on the dynamics of the system is discussed. The phenomenon of stochastic resonance is studied for a single uncoupled Fitzhugh-Nagumo neuron.

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Heating Mechanisms Of Magnetic Nanoparticles In Hyperthermia Treatment, Anna Lukawska, Gregory Kozlowski Jun 2013

Heating Mechanisms Of Magnetic Nanoparticles In Hyperthermia Treatment, Anna Lukawska, Gregory Kozlowski

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2013)

No abstract provided.

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Quantitative Rescattering Theory Of High-Order Harmonic Generation For Polyatomic Molecules, Anh-Thu Le, R. R. Lucchese, C. D. Lin Jun 2013

Quantitative Rescattering Theory Of High-Order Harmonic Generation For Polyatomic Molecules, Anh-Thu Le, R. R. Lucchese, C. D. Lin

Physics Faculty Research & Creative Works

We report applications of the quantitative rescattering theory (QRS) for calculation of high-order-harmonic generation (HHG) from polyatomic molecules in ultrashort linearly polarized intense laser pulses, using the example of the CCl₄ molecule. In particular, we present a detailed analysis and a treatment for the phase of the electron returning wave packet, which recollides with the parent molecular ion to emit high-energy photons. Our results show that Cooper-type minimum structures in the molecular photoionization cross section lead to quite distinguishable minima in the HHG spectra, even for unaligned polyatomic molecules.

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Maximum Likelihood Analysis Of Systematic Errors In Interferometric Observations Of The Cosmic Microwave Background, Le Zhang, Ata Karakci, Paul M. Sutter, Emory F. Bunn, Andrei Korotkov, Peter Timbie, Gregory S. Tucker, Benjamin D. Wandelt Jun 2013

Maximum Likelihood Analysis Of Systematic Errors In Interferometric Observations Of The Cosmic Microwave Background, Le Zhang, Ata Karakci, Paul M. Sutter, Emory F. Bunn, Andrei Korotkov, Peter Timbie, Gregory S. Tucker, Benjamin D. Wandelt

Physics Faculty Publications

We investigate the impact of instrumental systematic errors in interferometric measurements of the cosmic microwave background (CMB) temperature and polarization power spectra. We simulate interferometric CMB observations to generate mock visibilities and estimate power spectra using the statistically optimal maximum likelihood technique. We define a quadratic error measure to determine allowable levels of systematic error that does not induce power spectrum errors beyond a given tolerance. As an example, in this study we focus on differential pointing errors. The effects of other systematics can be simulated by this pipeline in a straightforward manner. We find that, in order to accurately …

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Atmospheric Pressure He-Air Plasma Jet: Breakdown Process And Propagation Phenomenon, Asma Begum, Mounir Laroussi, Mohammad Rasel Pervez Jun 2013

Atmospheric Pressure He-Air Plasma Jet: Breakdown Process And Propagation Phenomenon, Asma Begum, Mounir Laroussi, Mohammad Rasel Pervez

Electrical & Computer Engineering Faculty Publications

In this paper He-discharge (plasma jet/bullet) in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES) and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet …

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Measuring The Refractive Index Of Infrared Materials By Dual-Wavelength Fabry-Perot Interferometry, Griffin Taylor Jun 2013

Measuring The Refractive Index Of Infrared Materials By Dual-Wavelength Fabry-Perot Interferometry, Griffin Taylor

Physics

No abstract provided.

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Measurement Of Charm Fragmentation Fractions In Photoproduction At Hera, Margarita C. K. Mattingly, Zeus Collaboration Jun 2013

Measurement Of Charm Fragmentation Fractions In Photoproduction At Hera, Margarita C. K. Mattingly, Zeus Collaboration

Faculty Publications

The production of D^0, D^*+, D^+, D_s+ and Lambda_c^+ charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb^-1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the stangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum p_T >3.8 GeV and …

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