Bulletin of the American Physical Society
2013 Annual Fall Meeting of the APS Ohio-Region Section
Volume 58, Number 9
Friday–Saturday, October 4–5, 2013; Cincinnati, Ohio
Session C1: Poster Session (4:30 - 6:45) |
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Room: TUC Atrium |
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C1.00001: n-Valued Refined Neutrosophic Logic and Its Applications to Physics Florentin Smarandache The Neutrosophic Logic value of a given proposition has the values $T =$\textit{ truth, I }$=$\textit{ Indeterminacy, and F }$=$\textit{ falsehood}. We have defined in 1995 two types of n-valued logic: symbolic and numerical: \begin{itemize} \item \textit{The n-Symbol-Valued Refined Neutrosophic Logic. } \end{itemize} In general: $T$ can be split into many types of truths: $T_{1}, T_{2}, ..., T_{p}$, and $I$ into many types of indeterminacies: $I_{1}, I_{2}, ..., I_{r}$, and $F$ into many types of falsities: $F_{1}, F_{2}, ..., F_{s}$,where all $p, r, s \ge $\textit{ 1} are integers, and $p + r + s = n$. All subcomponents $T_{j}, I_{k}, F_{l}$ are symbols for $j\in $\textit{\textbraceleft 1,2,\textellipsis ,p\textbraceright ,} $k\in $\textit{\textbraceleft 1,2,\textellipsis ,r\textbraceright ,} and $l\in $\textit{\textbraceleft 1,2,\textellipsis ,s\textbraceright .} \begin{itemize} \item \textit{The n-Numerical-Valued Refined Neutrosophic Logic. } \end{itemize} In the same way, but all subcomponents $T_{j}, I_{k}, F_{l}$ are not symbols, but subsets of \textit{[0,1],} for all $j \in $ \textit{\textbraceleft 1,2,\textellipsis ,p\textbraceright ,} all $k \in $ \textit{\textbraceleft 1,2,\textellipsis ,r\textbraceright ,} and all $l \quad \in $ \textit{\textbraceleft 1,2,\textellipsis ,s\textbraceright .} \begin{itemize} \item Remarks: A) Similar generalizations can be done for \textit{n-Valued Refined Neutrosophic Set}, and respectively \textit{n-Valued Refined Neutrosopjhic Probability. B) }n-Valued Refined Neutrosophic Logic is applied in physics in cases where two or three of \textless A\textgreater , \textless antiA\textgreater , and \textless neutA\textgreater simultaneously coexist, where \textless A\textgreater may be a physical item (object, idea, theorem, law, theory). \end{itemize} [Preview Abstract] |
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C1.00002: Is Earth's temperature rise distributed uniformly? Gordon Aubrecht We compare the three world temperature records (Hadley Centre-Climate Research Unit database of 162 years, the National Oceanic and Atmospheric Administration, and the Goddard Institute of Space Sciences databases of 132 years) to the US (National Climate Data Center database of 118 years) and Australian (Australian Government Bureau of Meteorology database 103 years), a small part of the US (National Climate Data Center database of 118 years), and other records to see what the temperature data show about geographic variation. [Preview Abstract] |
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C1.00003: Tornadogenesis: Can horizontal rotation be tilted to vertical? Austin Mullen Tornadoes are one of mother nature's most dangerous creations. An average of 80 people are killed annually by tornadoes, and property damage averages {\$}4.9 billion per year. It is critically important to be able to forecast when and where a tornado will form to improve warning accuracy. Before this is possible, however, meteorologists must learn how tornadoes actually form. One theory of this tornadogenesis suggests that a horizontally rotating column of air, induced by low level wind shear, is tilted by the updraft of a thunderstorm to a vertical axis, then stretched to increase wind speeds and form the tornado's funnel. This experiment was designed to test if horizontal rotation can, by virtue of the law of conservation of angular momentum, be tilted to a vertical axis by a simulated updraft. To do this, a wind tunnel was constructed. Horizontal rotation was created by two opposing wind diffusers, and then an updraft hose was used to attempt to tilt the rotation to vertical. It was found that an average of 53.4{\%} of the horizontal rotation could be tilted to a vertical axis. Therefore, this experiment supports the hypothesis, as long as a tornado forms under well controlled laboratory conditions. In the real world, this rotation would be subjected to many other forces generated by the turbulent winds in and around a thunderstorm. This experiment does give data to support the hypothesis, but it also points out some of the flaws of the theory. [Preview Abstract] |
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C1.00004: Development of A Hybrid System for Laser Scribing and Characterization by Laser Beam Induced Current Jonathan L. DeWitt, Jon M. Stone, John Royston, Ryan Zeller, Meghan R. Mapes, Paul J. Roland, Zhaoning Song, Randy J. Ellingson, Adam B. Phillips, Michael J. Heben A hybrid system was developed for laser scribing and photovoltaic characterization for defect analysis of devices. In the scribing configuration, the system can isolate individual cells on a research scale device or perform the scribes necessary to integrate a module. In addition to scribing, the system can characterize photovoltaic effects of samples ranging in size from research sized devices to full modules with a resolution of 40 microns. High peak power lasers with wavelengths of 1064 nm, 532 nm, and 355 nm, which add flexibility to the system, are available for this system. For scribing the high power and multiple wavelengths allow the user to scribe most materials. For the Laser Beam Induced Current (LBIC) measurements the power of the system can be reduced and the appropriate wavelength can be selected to generate electron-hole pairs in the sample. For both of these configurations, the laser beam position and focal point are directed by galvanostatic mirrors and lens, respectively. In the LBIC configuration additional data acquisition software was developed. Data analysis software was also developed to manipulate data file and generate current maps. [Preview Abstract] |
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C1.00005: Do tall people walk faster than short ones? Andrew Murphy, Gabriela Popa We are investigating if tall people walk faster than short ones. We ask 20 students to walk, and we measured their speed as they walked with small, medium, and fast steps. We also recorded the horizontal and vertical components of the push force of the step on the floor. The velocity versus step size, velocity versus different components of the push force, and velocity versus height of the person's legs are analyzed. [Preview Abstract] |
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C1.00006: Peculiar Velocities of Wide Angle Tailed Radio Galaxies in Galaxy Clusters Thomas Steinberger, Jason Pinkney We analyze photometry and redshifts of clusters containing WAT (Wide Angle Tailed) radio galaxies with the goal of clarifying the connection between the WATs' bent tail morphology and the dynamical state of their host cluster. We have gathered data for 18 WAT clusters from a variety of sources. We've obtained B, V, and R CCD mosaics from the Kitt Peak 0.9-m telescope, and g and r CCD images from the Sloan Digital Sky Survey (SDSS). The redshifts come from the MX multifiber spectrograph, Gemini GMOS, and SDSS. The redshifts allow us to calculate the WAT peculiar velocities (i.e. radial velocity relative to the cluster) for all 18 clusters. Significant peculiar velocities were found for 39\% of the clusters before correcting for substructure, and 35\% after. Our deep imaging reveals that most WAT's are associated with first ranked galaxies with extended stellar envelopes that usually show distortions. Moreover, WAT's are usually found near peaks in the galaxy surface density. We conclude that most WAT's have small but non-zero speeds within their host subclusters. For some, the speeds may be high enough to bend the radio tails. [Preview Abstract] |
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C1.00007: Software Improvement In Differential Photometry Kevyn Wright Until about 15 years ago, there were no planets known besides those orbiting our own sun. Since then, advances in technology have made it possible to detect many more planets and has changed our notions of how planets form and evolve. Most of them have been detected using the radial-velocity method, watching the star wobble due to the gravitational effect of the planet. This, however, requires a large telescope, and is thus limited. The KELT (Kilodegree Extremely Little Telescope) project uses the transit method to detect planets. It entails watching a star for an extended period of time to record the slight dip in magnitude that occurs when the planet moves in front of the star. It can be done with much smaller telescopes, meaning there is a possibility for a lot more observation. While useful, a problem is that this dip can be less than 1\%, meaning that the software used to process the data must be very specialized, making maintenance of the code a job all its own. At Brigham Young, we followed up on some of the more interesting KELT targets. So far, the code used for the process has been modified to specialize it to this task and made more accessible to further modifications. The decentralized nature and the wealth of information of the KELT project means that this code is important to make sure the data can be processed in an efficient manner, but can also be adapted by others and further improved. [Preview Abstract] |
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C1.00008: Study of the Velocity Structure in Abell 154 R. Wesley Tobin, Robert Berrington Galaxy clusters are the largest, gravitationally bound structures in the universe. Galaxy cluster growth is believed to occur hierarchically through the merging of two or more nearby, smaller clusters. Actively merging clusters appear as multiple relaxed systems superimposed in position and/or velocity space. Cluster interactions constrain and quantify current knowledge in dark matter and dark energy, which provides a basis for the large-scale structure of the universe. Preliminary results of 147 new radial velocity measurements are presented for Abell 154. The cluster's velocity structure exhibits clearly defined substructure in the form of foreground and background galaxy groups. While these groups correlate by position, they differ significantly in radial velocity, suggesting little or no interaction. The most populous group (z $\approx $ 0.063) has a peculiar velocity distribution inconsistent with a dynamically relaxed state. However, the individual subclusters are not easily identifiable from position and radial velocity measurements alone. Statistical tests quantify the significance of substructure within this group and identify the position of any relics of interaction. Observed substructure is confirmed with multi-wavelength data from various sources. [Preview Abstract] |
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C1.00009: A Computational and Observational Study of Interstellar Thioformaldehyde Masers Lisa Simpson, Ian Hoffman Interstellar spectroscopy of thioformaldehyde (H$_{2}$CS) holds substantial promise because of the close relationship between the H$_{2}$CS molecule and the well-studied formaldehyde (H$_{2}$CO) molecule. We present here a summary of our computational investigation of H$_{2}$CS level populations and their relationship to known H$_{2}$CO 6-cm masers, as well as the details of an observational campaign of four H$_{2}$CS isotopologues. The maser pump model developed by Boland and de Jong (1981) for a known 4.8-GHz H$_{2}$CO maser in the Galactic star-forming region NGC 7538 has been extended to the analogous ground state transitions of four thioformaldehyde isotopologues: H$_{2}^{12}$C$^{32}$S, H$_{2}^{13}$C$^{32}$S, H$_{2}^{12}$C$^{34}$S, and H$_{2}^{12}$C$^{33}$S. Preliminary results from this model provide strong evidence for non-thermal maser emission from any of these isotopologues. Of considerable interest is the fact that this J=1 transition of H$_{2}$CS has never been detected astronomically. Higher-J transitions of H$_{2}$CS have been detected in various Galactic sources through thermal absorption but interpretations of these observations are ambiguous. A detection of the J=1 transition of H$_{2}$CS would alleviate many of these ambiguities. We describe our forthcoming experiment to search in NGC 7538 for both thermal and non-thermal emission and absorption from the considered H$_{2}$CS isotopologues. Both parts of this research effort will provide valuable and novel constraints on H$_{2}$CS and H$_{2}$CO. [Preview Abstract] |
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C1.00010: Velocity Dispersions in Active Galaxies with Low Mass Black Holes David DeColibus, Jason Pinkney, Edward Cackett, Kayhan Gultiken We have performed ground-based spectroscopic observations in support of a Hubble Space Telescope program to probe the SED's (spectral energy distributions) of LLAGNs (Low-Luminosity Active Galactic Nuclei). Our targets are six, medium redshift, radio loud galaxies with LLAGN. They were discovered in the Sloan Digital Sky Survey (SDSS) by Greene and Ho (2007a). We wish to improve upon the accuracy of the velocity dispersions produced by the SDSS pipeline. We use the ModSpec Spectrograph on the 2.4 Hiltner telescope at MDM Observatory. Our longslit spectra have a spectral range of about 4650 to 5650 \AA , which includes the MgB absorption lines and H$\beta$ + [OIII] emission lines. We describe the reduction of the CCD spectra and the fitting of absorption and emission lines using the direct pixel fitting technique. We combine multiple exposures to improve S/N ratio, but the uncertainties in velocity dispersion remain $>$ 8\% because of template mismatch. Our stellar velocity dispersions are largely consistent with the SDSS results and they predict black hole masses around $10^{6}$ M$_{sol}$ for most of our sample. [Preview Abstract] |
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C1.00011: A Self-consistent Theory of Gravitation and Particle Physics Wayne Lundberg A well-founded representation theory and non-commutative matrix algebra is known to be consistent with QCD {\&} QED. The representation theory models particle interactions, flavors and gluons with finitary geometry. A tetrahedron represents Higgs interaction vertex, consistent with string theory results (Kaku, 1990). An astrophysical theory is constructed following Guth, in which Higgs vertex has a dual representation as the kernel of a black hole. A Planck-scale tetrahedral physical singularity is bi-laterally asymmetric, explaining Galactic Annihilation Fountain. A finite physical singularity informs quantum gravity to construct an AdS/CFT representation of an information-preserving black hole. Tetrahedral quantum topology preserves CFT quanta in an anti-de Sitter space conformally attached at the throat of AdS-2 black holes. A triangulated AdS-2 black hole throat is consistent with the theory that highly-wound string are fractionalized (Mathur, 2005). Modern black hole theory examines fields deep within the throat, in which a ``highly macroscopic quantum effects make[s] the physics of very deep throats nonlocal'' (de Boers, 2010). An extra scalar field exists due to gravitational quanta in I-P black holes. This is consistent with string-theoretic duality, R$\leftrightarrow \surd \alpha $/r, and predicts that quanta preserved at the BH Planck scale are observed at astrophysical scale. Thus the smooth distribution of gravitational anomaly in lensing observations is explained by nonlocal gravitational fields. [Preview Abstract] |
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C1.00012: Multiband photometry of the eclipsing binary star NSVS 5754586 Erin Tuhey, Robert Berrington We report new multiband aperture differential photometry for the Northern Sky Variability Survey (NSVS) eclipsing star candidate star NSVS 5754586. All multiband images were taken by the Ball State University Observatory 0.4-meter telescope in the Johnson B and V, and Cousins R band passes. All images were bias and dark current subtracted, and flat field corrected using the ccdred image reduction package in the Image Reduction and Analysis Facility (IRAF) software suite. Differential aperture photometry was performed with the AIP4WIN software package. We compare our measured light curves with the unfiltered CCD photometry reported by the NSVS. The measured light curves are analyzed by the physics of eclipsing binaries (PHOEBE) software package, and best-fit orbital parameters and stellar models are reported. [Preview Abstract] |
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C1.00013: Multiband Differential Photometry of the Eclipsing Star Candidates NSVS 5750160, NSVS 3068865 and ASAS 184708-3340.2 Robert Berrington, Erin Tuhey We present new multiband differential aperture photometry of the three eclipsing star candidates NSVS 5750160 and NSVS 3068865 from the Northern Variability Sky Survey (NSVS) and ASAS 184708-3340.2 from the All Sky Automated Survey (ASAS). All images were acquired by either the Ball State University Observatory 0.4-meter telescope for the northern hemisphere objects, or the Southern Association for Research in Astronomy (SARA) 0.6-meter telescope located at the Cerro-Tololo Inter-American Observatory (CTIO) for the southern hemisphere objects. We report new multiband Johnson-Cousins B, V, and R band differential light curves, and compare with the NSVS and ASAS public release data. All light curves are analyzed with the Wilson and Devinney model implemented by the Physics of Eclipsing Binary (Phoebe) software package. We report the best-fit orbital parameters, and investigate possible star-spot models for these systems. [Preview Abstract] |
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C1.00014: Modeling of Eclipsing Binary System NSVS 5726288 Matthew Knote NSVS 5726288 is a short-period eclipsing binary system discovered by the NSVS (Northern Sky Variability Survey), a survey conducted in the early 2000s that produced light curves for over 14 million objects ranging from 8th to 15th magnitudes in order to identify variable stars in the northern celestial hemisphere. My observations of NSVS 5726288 comprise the first follow-up study to the original survey. I have used the light curves produced from my observations to model the system using the Wilson-Devinney code, allowing for the determination of system characteristics such as inclination, component temperatures, and the mass ratio. [Preview Abstract] |
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C1.00015: Imbalanced fermionic superfluids and emerging bosonic phases in a 2D array of coupled tubes Kuei Sun, C.J. Bolech We study two-species imbalanced fermionic superfluids in an 2D array of 1D tubes that are coupled via single-particle and pair tunnelings between nearest neighbors. We build a model incorporating the interplay of Cooper pairing, spin imbalance (or magnetization) as well as intertube tunneling and obtain imbalance profiles accompanied with oscillatory pairing order parameter of the system, reminiscent of a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. Our model shall describe the development of signatures characteristic of the incipience of the dimensional crossover between 1D and 3D. In addition, we find that the state of unpaired majority spins in the system undergoes an incompressible-compressible transition as a function of magnetic field and tunneling strength. We show that such phase transition has a bosonic nature and can be well described by a modified Bose-Hubbard model with coupling between nearest-neighbor sites' occupation parities. [Preview Abstract] |
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C1.00016: Probe spectrum of Rydberg atoms undergoing collective spontaneous emission Lyndon Cayayan, Jacob Pauley, James Clemens We study a collection of $N$ driven, damped Rydberg atoms with either independent or collective damping. The strong dipole-dipole interaction of the atoms gives rise to a Rydberg blockade and collective quantum jumps between a dark state with most atoms in the ground state and a bright state with most atoms in the excited state. Using the Quantum Toolbox in Python (QuTiP) we calculate the probe spectra of the Rydberg atoms for varying dipole-dipole interaction strengths and compare results for collective and independent emission. [Preview Abstract] |
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C1.00017: A New Algorithm for Time Evolution of Quantum Trajectories Douglas McNally, James Clemens Quantum trajectory simulations are a Monte Carlo method which use ensemble averaging to generate wave function evolution for open quantum systems. Agreement with results from master equations increases with the number of independent realizations of the system evolution or ``trajectories.'' It is often computationally preferable to use the Monte Carlo approach which requires averaging over many problems using a state vector, as opposed to using the master equation which requires solving a single problem using a density matrix. Past implementations of a quantum trajectories algorithm, such as mcsolve in the popular quantum optics package The Quantum Toolbox in Python (QuTiP), depend on high order differential equation solvers to obtain time evolution. The time evolution is given by the Schrodinger equation using a non-Hermitian effective Hamiltonian. Herein an alternate method which utilizes matrix diagonalization for trivial time evolution (matrix exponentiation) is presented and implemented in Python. This also allows the determination of the times at which a collapse or ``quantum-jump'' occurs to be done in advance using only a simple zero-finding technique and thus eliminating the need for high precision time intervals or backtracking. Agreement with existing implementations and master equation solutions is shown. [Preview Abstract] |
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C1.00018: Exploration of a qubit assisted quantum optomechanical system Stephen Kelly, Andrew Jacobs, James Clemens The field of quantum optomechanics has been studied with a focus upon the dynamics of an optical cavity field coupled to a mechanical oscillator. We consider here the scenario of a two-level atom qubit within the optical cavity. In this case, there are three systems coupled together: the qubit, the electromagnetic radiation field within the cavity, and the vibrational states of the oscillator. The occupation of states of the atom, cavity photon number, and mirror phonon number is found to be dependent upon the coupling between them, along with the driving radiation entering the cavity. We present results for the probe spectrum of the system in the steady state. [Preview Abstract] |
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C1.00019: The forelimb of \textit{Tyrannosaurus rex}: a pathetic vestigial organ or an integral part of a fearsome predator? S.A. Lee The function of the forelimb of \textit{Tyrannosaurus rex} remains a controversial topic. It was too short to transfer food directly to the mouth. Since \textit{Tyrannosaurus rex} was bipedal, the forelimb was not involved in locomotion. Suggestions for its possible use include providing an initial push for a laying animal to stand or to hold position during mating. We report numerical calculations performed to determine the moment of inertia of the forearm and the torques generated by the muscles of the arm, based on three-dimensional representations of the forelimb. Our results imply that the forelimb was capable of very high angular accelerations. We interpret this as being consistent with the hypothesis that the forelimb was used to control a struggling prey animal immediately before the death blow was delivered by the teeth of \textit{Tyrannosaurus rex}. [Preview Abstract] |
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C1.00020: Substrate Dependent Modulation of Cellular Response to External Electric Field Toloo Taghian, Abdul Sheikh, Daria Narmoneva, Andrei Kogan Although the regulatory effect of external electric field (EF) on cellular behaviors in vitro has been confirmed, the biophysical mechanisms of interaction of EF with cells are not clear. EF-cell interactions may be affected by both distribution of the induced EF within the cell, as well as the properties of the extracellular matrix (ECM), which is known to regulate cell response to the external stimuli. Therefore, mechanistic studies of EF interactions with the cell and its substrate are essential for the efficient control of the cell responses and development of EF-based therapies. To address this issue, we have developed a combined theoretical-experimental approach. Our 3D EF-cell interaction model solves Maxwell's equation (ANSOFT\textunderscore HFSS) in wide frequency range to provide a precise induced EF distribution within the cell in its native configuration. Model predictions are compared with the experimentally measured responses of endothelial cells to the EF, including growth factor release and capillary morphogenesis, for cells cultured on synthetic and natural ECM. The results show that cell response to EF varies with EF frequency in a substrate dependent manner, thus providing a mechanistic insight in the biophysics of EF-cell interactions. [Preview Abstract] |
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C1.00021: A perfusion system for the fluorescence-based monitoring of physiological responses to high hydrostatic pressures Paul Urayama, Jeff Maltas, Zac Long, Alison Huff Hydrostatic pressures of a few-hundred atmospheres affect biological components and processes, for example, the stability of macromolecular assemblies, the biophysical properties of membranes, enzymatic activity, and protein structure. These in turn lead to a range of pressure effects on cellular physiology. Here we present a mirco-perfusion system designed for the real-time spectroscopic monitoring of cellular systems under high pressure. The system consists of an optically-compatible pressure chamber and interchangeable fluid reservoirs. Perfusion is achieved using a dual pressure-generator configuration, where one positive-displacement generator is compressed while the other is retracted, thus maintaining pressure while achieve fluid flow. Control over perfusion rate (typically in the 10 $\mu $l/s range) and the ability to change between fluid reservoirs while under pressure (up to 600 atm) is demonstrated. The real-time monitoring of the response of cellular autofluorescence to mitochondrial functional modifiers (e.g., cyanide) while under pressure is also demonstrated. [Preview Abstract] |
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C1.00022: Utilization of dual-wavelength pH-sensing dyes in the characterization of pH buffers under hydrostatic pressure Paul Urayama, J. August Folz, Zachariah P. Callahan Biologically-compatible pH-buffer solutions are routinely used in biochemical and biophysical studies at ambient pressure. When using buffers under high-pressure however, the existence of a thermodynamic volume change ($\Delta $V) for the buffer's acid-dissociation reaction leads to a pressure-dependent equilibrium constant (pK$_{\mathrm{a}})$. The result is a pressure-induced shift in pH. Here we use pH-sensing, dual-wavelength probe dyes, SNARF-1 and SNARF-5F, to characterize the pressure-response of three biologically-relevant buffers: MOPS, HEPES, and TRIS. Emission spectra from the dyes, excited at 337-nm wavelength, are used to track the pressure-induced change in pH of the buffer systems, up to 600 atm (61 MPa). From this the $\Delta $V of the buffers' acid-dissociation reaction was determined and found to be in the 0 to $+$10 ml/mol range. Results presented are important when accounting for pressure-induced pH changes during high-pressure biophysical studies because a large range of biochemical reactions involve H$^{\mathrm{+}}$ and have a $\Delta $V similar in range to the these buffers. [Preview Abstract] |
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C1.00023: Effects of spin-dependent interfaces on electronic transport in hetero-structure superconductor/ferromagnet junctions Kuei Sun, Nayana Shah, Smitha Vishveshwara We study electronic transport in junctions consisting of a superconductor (S) electrode and two ferromagnet (F) leads having spin-dependent S-F interfaces associated with magnetization in the F leads. We model the system using an extended Blonder-Tinkham-Klapwijk treatment with a key modification that accounts for these spin-dependent interfacial barriers (SDIB). We compute current-voltage relations as a function of parameters characterizing the SDIB, magnetization in the F leads, geometry of the junction, and temperature. Our results reveal a rich range of significantly altered physics due to a combination of interfering spin-dependent scattering processes and population imbalance in the ferromagnets, such as a significant enhancement in crossed Andreev current and a sign change in the relative difference between resistance of two cases having a antiparallel or parallel alignment of the magnetization in the F leads, respectively. Our model well describes various experimental data of positive and negative relative resistance, both within sufficiently large parameter regions. [Preview Abstract] |
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C1.00024: Calculation of Entanglement Entropy in Fermion Lattices Michelle Storms, Rajiv Singh We study bipartite entanglement entropies of the ground and excited states of model fermion systems, where a staggered potential, $\mu_s$, induces a gap in the spectrum. Ground state entanglement entropies satisfy the ``area law,'' and the ``area law coefficient'' is found to diverge as a logarithm of the staggered potential, when the system has an extended Fermi surface at $\mu_s=0$. On the square-lattice, we show that the coefficient of the logarithmic divergence depends on the Fermi surface geometry and its orientation with respect to the real-space interface between subsystems, and is related to the Widom conjecture as enunciated by Gioev and Klich (Phys. Rev. Lett. 96, 100503 (2006)). For point Fermi surfaces in two-dimension, the ``area-law'' coefficient stays finite as $\mu_s \rightarrow 0$. The von Neumann entanglement entropy associated with the excited states follows a ``volume law'' and allows us to calculate an entropy density function $s_V(e)$, which is substantially different from the thermodynamic entropy density function $s_T(e)$, when the lattice is bipartitioned into two equal subsystems but approaches the thermodynamic entropy density as the fraction of sites integrated out of the larger subsystem approaches unity. [Preview Abstract] |
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C1.00025: Efficient Variational Method for Approximating Ground States of 1D Systems Sangwoo Chung, Kuei Sun, C.J. Bolech The matrix product states ansatz, which has been successful in approximating one-dimensional quantum lattice systems by variational methods, has recently been extended to be able to describe gas and liquid systems in the continuum. We demonstrate that this extension, known as the continuous matrix product state, can accurately describe ground state properties of interacting Bosonic and Fermionic gas systems. [Preview Abstract] |
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C1.00026: Sputtered Thin Film Polycrystalline Molybdenum on Glass Patrick Krantz, Zhaoning Song, Adam Phillips, Michael Heben Molybdenum (Moly) thin films are used as the back contact in a variety of photovoltaic (PV) devices. In the substrate configuration, the Moly film is deposited on a substrate, typically glass, prior to PV layer deposition. The crystal structure and electrical properties of the Moly film can have a significant impact on the PV device performance. Therefore, it is critical to have well characterized Moly films prior to PV material deposition. The parameter space of sputtered Moly onto soda-lime glass was investigate and is reported here. Surface morphology, crystalline structure, thickness, and resistivity were measured, and delamination behavior of the Moly films was explored. Sputtering parameters that result in high quality crystalline structure and high conductivity were determined for a range of Moly film thicknesses. [Preview Abstract] |
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C1.00027: Modeling and Study of Photovoltaic Materials Based on Density Functional Theory Alex Cimaroli, Wanjian Yin, Tingting Shi, Yanfa Yan Understanding semiconductorproperties and defect states by use of Density Functional Theory (DFT) may allowmore efficient solar cells tobe made. According to calculations, intrinsic grain boundaries in CuInSeproduce deep gap states, and grain boundaries in CuZnSnSeact as Shockley-Read-Hall recombination centers. DFTwasused to aid in finding novel materials that have not been studied yet. Specifically, some of the Cu-V-VImaterials may prove to make good absorber layer materials aftercalculatingthe stability of different stoichiometries and their band gaps. The Al-O complex defect in Silicon is studied to understand its effect on the efficiency of Silicon solar cells. Some of the Al-O complexes produce deep levels in the band gap of Silicon, which reduces carrier lifetime. Lastly, Zinc Phosphide can grow preferentially along the [220] direction. DFT was used to calculate the surface energy of the different planes of Zinc Phosphide. The configurational energy should help to elucidate the nature of preferred orientation of Zinc Phosphide. (220)-oriented Zinc Phosphide thin films may have unique electronic and optical properties that can be explained by DFT. [Preview Abstract] |
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C1.00028: Research Efforts on Thin-film Solar Cells Alex Cimaroli, Naba Paudel, Tejas Prabhakar, Yue Yu, Chuanxiao Xiao, Corey Grice, Jie Ge, Yanfa Yan Thin film solar cells and earth-abundant, thin-film solar cells can help to reduce the cost of manufacturing solar panels. Close-space sublimation (CSS) is used to grow CdTe and ZnP thin films. CSS is a cheap and scalable approach to thin-film growth. CSS-grown CdTe solar cells have achieved in-lab efficiencies of 15.8{\%}, which is higher than that of sputter-deposited CdTe (14.5{\%}). ZnP is an earth-abundant absorber layer material that has favorable optical and electronic properties. It is difficult to make a good junction with ZnP since it cannot be doped n-type. CZTS is an earth-abundant, non-toxic absorber layer material with a tunable band gap. Spray pyrolysis is used as a cost-effective approach to make superstrate-type devices with CdS or ZnS as the window layer. CuSbS is a new material to be used as an absorber layer. Sputter-deposited films have achieved an efficiency of 0.32{\%} thus far. Sputter-deposited InO is studied as a front contact material. When grown in a hydrogen ambient, films have been fabricated with 85{\%} transmission, $\sim$ 10cm$^{-3}$ carrier concentration, and $\sim$ 20 cm/V-s mobility. Thin metal oxides have been studied as candidates to replace Cu as the back contact to CdTe solar cells. They may help to improve the stability of CdTe solar cells. The best candidate is MoO$_{\mathrm{-x}}$/Au. [Preview Abstract] |
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C1.00029: LHCb High Level Trigger design issues for post Long Stop 1 running Michael Sokoloff, Johannes Albrecht, Vladimir Gligorov, Gerhard Raven, Michael Williams The LHCb High Level Trigger uses two stages of software running on an Event Filter Farm (EFF) to select events for offline reconstruction and analysis. The first stage (Hlt1) processes approximately 1 MHz of events accepted by a hardware trigger. In 2012, the second stage (Hlt2) wrote 5 kHz to permanent storage for later processing. Following the LHC's Long Stop 1 (anticipated for 2015), the machine energy will increase from 8 TeV in the center-of-mass to 13 TeV and the cross sections for beauty and charm are expected to grow proportionately. We plan to increase the Hlt2 output to 12 kHz, some for immediate offline processing, some for later offline processing, and some ready for immediate analysis. By increasing the absolute computing power of the EFF, and buffering data for processing between machine fills, we should be able to significantly increase the efficiency for signal while improving signal-to-background ratios. In this poster we will present several strategies under consideration and some of the tools we are using to evaluate these strategies. [Preview Abstract] |
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C1.00030: Dynamical Effects of Doping in Single Wall Carbon Nanotube Solutions and Films Neale O. Haugen, Adam B. Phillips, Tieneke E. Dykstra, Michael J. Heben, Randy J. Ellingson We report a transient absorption (TA) study of doping in single-walled carbon nanotube (SWNT) films and solutions. An aqueous solution of pulsed laser vaporization SWNTs were spray-deposited to form films; the films were soaked in a solution of nitric acid, which collapsed them through removal of the surfactant. The nitric acid treatment induces p-type doping by protonation, and suppresses the lowest energy semiconducting (E1) optical absorption. Photo-exciting at 1215 nm and probing at the E1 peak yielded a strong photoinduced absorption (PA). De-doping the film by heating to 250$^{\circ}$C for 30 minutes recovered the E1 linear absorption feature and converted the transient PA to a photoinduced bleach (PB). Films heated in air re-dope within a day in laboratory air, while films heated in nitrogen resisted re-doping under ambient laboratory air. Solution measurements involving oxygenated and deoxygenated solutions and different surfactants indicate the doping depends strongly on adsorbed molecular oxygen. [Preview Abstract] |
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C1.00031: Time Resolved Photoluminescence of Semiconductor Thin Films for Photovoltaics Paul Roland, Khagendra Bhandari, Naba Paudel, Yanfa Yan, Randy Ellingson Minority carrier lifetime is a fundamental material property of key interest in photovoltaic devices which, combined with diffusion coefficient and device architecture, determines the probability of a charge carrier contributing to the photogenerated current. Time resolved photoluminescence is a non-destructive optical technique which probes the decay rate of charge carriers within a material or thin film stack following excitation from an ultrafast laser pulse. Here, we present mean carrier lifetime measurements of a variety of photovoltaic materials and devices, focusing on Cadmium Telluride and Lead Sulfide Quantum Dots. [Preview Abstract] |
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C1.00032: Towards iron sulfide nanocrystal-based photovoltaic devices: progress in synthesis, optimization, and solar cell applications Tyler Kinner, Brad Monahan, Khagendra Bhandari, Terry Bigioni, Randy Ellingson Iron sulfide (FeS$_2$, pyrite), a naturally abundant and non-toxic semiconductor with a high absorption coefficient and functional band gap for potential use in photovoltaics (PV). Our research focuses on the synthesis and optimization of iron sulfide nanocrystals (NCs) for PV application. Considerable challenges exist for FeS2 NCs, namely concerning crystallinity and phase purity. Here, we present synthetic and post-synthetic routes to overcome defect issues in an effort to fabricate functional FeS$_2$ NC based devices, as well as attempts at synthesis of Co$_x$Fe$_{1-x}$S$_2$ for use as an n-type heterojunction partner. [Preview Abstract] |
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C1.00033: New results for the $\beta$ decay of $^{144}$Cs into $^{144}$Ba Richard Scotten, Michael Carpenter, Shaofei Zhu The partial level structure of neutron-rich $^{144}$Ba was deduced following the $\beta$ decay of $^{144}$Cs. The number of known levels has been greatly expanded, and states with spins $\le 5 \hbar$ have been observed. The experiment was conducted using a re-accelerated beam of $^{144}$Cs extracted from CARIBU, and implanted in a Pb foil placed at the target position of the Gammasphere array. The comparative $\beta$ decay half-life, log $ft$, has been classified according to the degree of forbiddenness for 102 transitions which feed the 2$^+_1$ in $^{144}$Ba. A preliminary result of 5.83(4) favors a positive parity assignment for the $^{144}$Cs spin-1 groundstate. [Preview Abstract] |
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C1.00034: Heisenberg Uncertainty Principle Extended to \textit{n-plets} Florentin Smarandache All measurable properties of a physical system come in n-plets; as one measures a member of the \textit{n-plets }very accurately, consequently the other left \textit{n-1} members of the \textit{n-plets} are measured very inaccurately. If there is a minimum uncertainty in a member's measurement, there is a maximum uncertainty in the other \textit{n-1} members' measurements. The product of the n uncertainties corresponding respectively to the measurements of the $n$ members is constant: $u_{1}$\textit{\textbullet u}$_{2}$\textit{\textbullet \textellipsis \textbullet u}$_{n} = h =$\textit{ 6.626 $\times$ 10}$^{-34}$\textit{ kg m}$^{2} s^{-1}$ where $h$ is Planck's constant. \begin{itemize} \item Open Question: If possible to simultaneously measure $m$ members of the \textit{n-plets} very accurately, for \textit{2 }$\le m \le $\textit{ n-1} would consequently result that the other left $n-m$ members of the \textit{n-plets} are measured very inaccurately? \end{itemize} [Preview Abstract] |
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C1.00035: CdS/PbS(Quantum Dot) thin film solar cells Khagendra Bhandari, Paul Roland, Hasitha Mahabaduge, Neale Haugen, Corey Grice, Sohee Jeong, Tieneke Dykstra, Jianbo Gao, Randy Ellingson We present results of studies of heterojunction PbS quantum dot (QD) solar cells deposited on n-type window layers consisting of RF magnetron sputtered CdS. Compared to previously reported PbS-QD solar cells, these solar cells exhibit large open circuit voltage. We report results of studies of the performance of the devices as a function of CdS film thickness of 70 nm and PbS QD diameter. Under simulated AM1.5G illumination, the best results show short circuit current as high as 12mA-cm$^{-2}$, an open circuit voltage of 0.65 volts, and efficiency as high as 3.3{\%}. [Preview Abstract] |
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C1.00036: Professional Science Master's Degree in Photovoltaics Patrick Krantz, Randy Ellingson, Michael Heben Over the past 25 years, the University of Toledo has invested heavily in PV science and technology and has developed world-class expertise and facilities for PV research and commercialization. University of Toledo's Professional Science Master's degree in Photovoltaics (PSM-PV), offered by UT's Department of Physics and Astronomy, in conjunction with the Wright Center for Photovoltaics Innovation and Commercialization, prepares students for successful careers in the burgeoning photovoltaics industry. The two year program builds a strong scientific knowledge base rooted in condensed matter physics and materials science and develops laboratory skills and business management practices to prepare the next generation of PV professionals. Students are exposed to a wide range of cutting edge research activities in laboratories of world-class faculty, and participate in a 24 week corporate sponsored internship that provides real world experience.~ The program is affiliated with the National Professional Science Master's Association. Past graduates have found jobs within the~Ohio and Michigan PV industry, and with the US Department of Energy's Solar Energy Technologies Program. [Preview Abstract] |
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