# Browsing by Subject "physics, multidisciplinary"

Now showing 1 - 19 of 19

- Results Per Page
1 5 10 20 40 60 80 100

- Sort Options
Ascending Descending

Item Alfven-Wave Studies On Pretext(1985) Valanju, P. M.; Bengtson, R. D.; Booth, W. D.; Cook, R. W.; Evans, T. E.; Mahajan, S. M.; Oakes, M. E.; Ross, D. W.; Surko, C. M.; Valanju, P. M.; Bengtson, R. D.; Booth, W. D.; Cook, R. W.; Evans, T. E.; Mahajan, S. M.; Oakes, M. E.; Ross, D. W.Show more Item Application Of The MCMC Method For The Calibration Of DSMC Parameters(2011-05) Strand, J. S.; Goldstein, D. B.; Strand, James S.; Goldstein, David B.Show more A Markov Chain Monte Carlo (MCMC) algorithm was employed to obtain a calibrated distribution for the hard sphere diameter, the VHS reference diameter, and the temperature viscosity exponent of argon, for use in the Direct Simulation Monte Carlo (DSMC) method. Shock-tube experiments from Alsmeyer [1] were used to provide the necessary calibration data for use in the MCMC method. The DSMC method used in this work employs the algorithm of Bird [2], with modifications to allow for the efficient simulation of a 1D shock. When calibrating for the hard sphere diameter (the temperature viscosity exponent is set to 0.5 for the hard sphere method), the results of the MCMC method agree with a simple brute-force method, and a single value for the hard-sphere diameter is obtained. For the VHS method, however, when simultaneously calibrating the VHS reference diameter and the temperature viscosity exponent, we find that normalized density data alone does not provide sufficient information to obtain a single solution for both parameters. Instead we find a band in parameter space where acceptable solutions are obtained.Show more Item An Audible Demonstration Of The Speed Of Sound In Bubbly Liquids(2008-10) Wilson, Preston S.; Roy, Ronald A.; Wilson, Preston S.Show more The speed of sound in a bubbly liquid is strongly dependent upon the volume fraction of the gas phase, the bubble size distribution, and the frequency of the acoustic excitation. At sufficiently low frequencies, the speed of sound depends primarily on the gas volume fraction. This effect can be audibly demonstrated using a one-dimensional acoustic waveguide, in which the flow rate of air bubbles injected into a water-filled tube is varied by the user. The normal modes of the waveguide are excited by the sound of the bubbles being injected into the tube. As the flow rate is varied, the speed of sound varies as well, and hence, the resonance frequencies shift. This can be clearly heard through the use of an amplified hydrophone and the user can create aesthetically pleasing and even musical sounds. In addition, the apparatus can be used to verify a simple mathematical model known as Wood's equation that relates the speed of sound of a bubbly liquid to its void fraction. (c) 2008 American Association of Physics Teachers.Show more Item Detection Of Gravitational Collapse(1983) Wheeler, J. C.; Wheeler, J. A.; Wheeler, J. Craig; Wheeler, John A.Show more Item Discontinuous Galerkin Methods For The Boltzmann-Poisson Systems In Semiconductor Device Simulations(2011-07) Cheng, Y. D.; Gamba, I. M.; Majorana, A.; Shu, C. W.; Cheng, Yingda; Gamba, Irene M.Show more We are interested in the deterministic computation of the transients for the Boltzmann-Poisson system describing electron transport in semiconductor devices. The main difficulty of such computation arises from the very high dimensions of the model, making it necessary to use relatively coarse meshes and hence requiring the numerical solver to be stable and to have good resolution under coarse meshes. In this paper we consider the discontinuous Galerkin (DG) method, which is a finite element method using discontinuous piecewise polynomials as basis functions and numerical fluxes based on upwinding for stability, for solving the Boltzmann-Poisson system. In many situations, the deterministic DG solver can produce accurate solutions with equal or less CPU time than the traditional DSMC (Direct Simulation Monte Carlo) solvers. Numerical simulation results on a diode and a 2D double-gate MOSFET are given.Show more Item Effect Of Noise And Pump Depletion On The Plasma Beat Wave Accelerator(1985) Horton, W.; Tajima, T.; Horton, W.; Tajima, T.Show more Item Fundamental Study Of Optical Threshold Layer Approach Towards Double Exposure Lithography(2009-04) Gu, X. Y.; Berro, A. J.; Cho, Y.; Jen, K.; Lee, S.; Nagai, T.; Ogata, T.; Durand, W. J.; Sundaresan, A.; Lancaster, J. R.; Jockusch, S.; Zimmerman, P.; Turro, N. J.; Willson, C. G.; Gu, Xinyu; Cho, Younjin; Jen, Kane; Lee, Saul; Ngai, Tomoki; Durand, William J.; Jockusch, Steffen; Willson, C. G.Show more 193 immersion lithography has reached its maximal achievable resolution. There are mainly two lithographic strategies that will enable continued increase in resolution. Those are being pursued in parallel. The first is extreme ultraviolet (EUV) lithography and the second is double patterning (exposure) lithography. EUV lithography is counted on to be available in 2013 time frame for 22 nm node([1]). Unfortunately, this technology has suffered several delays due to fundamental problems with source power, mask infrastructure, metrology and overall reliability([2]). The implementation of EUV lithography in the next five years is unlikely due to economic factors. Double patterning lithography (DPL) is a technology that has been implemented by the industry and has already shown the proof of concept for the 22nm node([3]). This technique while expensive is the only current path forward for scaling with no fundamental showstoppers for the 32nm and 22nm nodes. Double exposure lithography (DEL) is being proposed as a cost mitigating approach to advanced lithography. Compared to DPL, DEL offers advantages in overlay and process time, thus reducing the cost-of-ownership (CoO)([4][5]). However, DEL requires new materials that have a non-linear photoresponse. So far, several approaches were proposed for double exposure lithography, from which Optical Threshold Layer (OTL) was found to give the best lithography performance according to the results of the simulation([4][5]). This paper details the principle of the OTL approach. A photochromic polymer was designed and synthesized. The feasibility of the material for application of DEL was explored by a series of evaluations.Show more Item Nonequilibrium Ionization Phenomena Behind Shock Waves(2011-07) Panesi, M.; Magin, T.; Huo, W.; Panesi, MarcoShow more An accurate investigation of the behavior of electronically excited states of atoms and molecules in the post shock relaxation zone of a trajectory point of the FIRE II flight experiment is carried out by means of a one-dimensional flow solver coupled to a collisional-radiative model. In the rapidly ionizing regime behind a strong shock wave, the high lying bound electronic states of atoms are depleted. This leads the electronic energy level populations of atoms to depart from Boltzmann distributions which strongly affects the non-equilibrium ionization process as well as the radiative signature. The importance of correct modeling of the interaction of radiation and matter is discussed showing a strong influence on the physico-chemical properties of the gas. The paper clearly puts forward the shortcomings of the simplified approach often used in literature which strongly relies on the escape factors to characterize the optical thickness of the gas.Show more Item Operation Of The NuMi Beam Monitoring System(2006-11) Zwaska, R. M.; Indurthy, D.; Keisler, R.; Kopp, S.; Mendoza, S.; Pavlovich, Z.; Proga, M.; Bishai, M.; Diwan, M.; Viren, B.; Harris, D.; Marchionni, A.; Morfin, J.; McDonald, J.; Naples, D.; Northacker, D.; Erwin, A.; Ping, H. C.; Velissaris, C.; Zwaska, Robert M.; Indurthy, Dharma; Keisler, Ryan; Kopp, Sacha; Mendoza, Steven; Pavlovich, Zarko; Proga, MarekShow more The NuMI (Neutrinos at the Main Injector) facility produces an intense neutrino beam for experiments. The NuMI Beam Monitoring system consists of four arrays of ion chambers that measure the intensity and distribution of the remnant hadron and tertiary muon beams produced in association with the neutrinos. The ion chambers operate in an environment of high particle fluxes and high radiation.Show more Item Optical Threshold Layer And Intermediate State Two-Photon Pag Approaches To Double Exposure Lithography(2009-04) Berro, A. J.; Gu, X. Y.; O'Connor, N.; Jockusch, S.; Nagai, T.; Ogata, T.; Zimmerman, P.; Rice, B. J.; Adolph, E.; Byargeon, T.; Gonzalez, J.; Turro, N. J.; Willson, C. G.; Berro, Adam J.; Gu, Xinyu; Nagai, Tomoki; Ogata, Toshiyuki; Adolph, Elizabeth; Byargeon, Travis; Gonzalez, Jose; Willson, C. GrantShow more Intermediate state two-photon (ISTP) photoacid generator (PAG) and optical threshold layer (OTL) approaches to double exposure lithography have been explored. We have synthesized >transparent> PAG and sensitizer compounds for use in ISTP systems and have demonstrated the possibility of utilizing such energy transfer systems to generate acid. We have also synthesized side chain liquid crystalline polymers and small molecule azobenzene compounds for use in OTL applications and have begun photoswitching studies.Show more Item Polymer Dissolution Model: An Energy Adaptation Of The Critical Ionization Theory(2009-02) Chauhan, S.; Somervell, M.; Scheer, S.; Mack, C.; Bonnecaze, R. T.; Willson, C. G.; Chauhana, Siddharth; Bonnecaze, Roger T.; Willson, C. GrantShow more The current scale of features size in the microelectronics industry has reached the point where molecular level interactions affect process fidelity and produce excursions from the continuum world like line edge roughness (LER). Here we present a 3D molecular level model based on the adaptation of the critical ionization (CI) theory using a fundamental interaction energy approach. The model asserts that it is the favorable interaction between the ionized part of the polymer and the developer solution which renders the polymer soluble. Dynamic Monte Carlo methods were used in the current model to study the polymer dissolution phenomenon. The surface ionization was captured by employing an electric double layer at the interface, and polymer motion was simulated using the Metropolis algorithm. The approximated interaction parameters, for different species in the system, were obtained experimentally and used to calibrate the simulated dissolution rate response to polymer molecular weight and developer concentration. The predicted response is in good agreement with experimental dissolution rate data. The simulation results support the premise of the CI theory and provide an insight into the CI model from a new prospective. This model may provide a means to study the contribution of development to LER and other related defects based on molecular level interactions between distinct components in the polymer and the developer.Show more Item Real Beads On Virtual Strings: Charged Particles On Magnetic Field Lines(2012-11) Breizman, Boris; Khudik, Vladimir; Breizman, Boris; Khudik, VladimirShow more We discuss a similarity between the drift of a charged particle inside a slowly moving solenoid and the motion of a fluid element in an ideal incompressible fluid. This similarity can serve as a useful instructional example to illustrate the concepts of magnetic field lines and magnetic confinement. (C) 2012 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4746068]Show more Item Relaxation Of Brownian Particles In A Gravitational Field(2009-03) Saka, Halil; Bengtson, Roger D.; Reichl, Linda E.; Saka, Halil; Bengtson, Roger D.; Reichl, Linda E.Show more We describe an upper level undergraduate experiment on the time-dependent behavior of a suspension of Brownian particles under gravitational attraction. We employed the Fokker-Planck equation in the strong friction limit and measured the time-evolution of the probability distribution for 1.0 mu m diameter latex Brownian particles in water at room temperature and pressure. The experiment provides evidence of the atomic nature of water.Show more Item Review: Resource Letter Ps-2: Physics Of Sports(2011-06) Frohlich, Cliff; Frohlich, CliffShow more This Resource Letter provides a guide to the literature on the physics of sports, updating Resource Letter PS-1, published 25 years ago (Ref. 17). The intent is to suggest literature for anyone curious about the basic physics of particular sports, for physics teachers searching for sports examples to augment their teaching, and for physicists contemplating research on unsolved sports-related questions. (C) 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3552157]Show more Item Simulating Irregular Source Geometries For Ionian Plumes(2011-07) McDoniel, W. J.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.; Buchta, D. A.; Freund, J.; Kieffer, S. W.; McDoniel, W. J.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.Show more Volcanic plumes on Io respresent a complex rarefied flow into a near-vacuum in the presence of gravity. A 3D Direct Simulation Monte Carlo (DSMC) method is used to investigate the gas dynamics of such plumes, with a focus on the effects of source geometry on far-field deposition patterns. A rectangular slit and a semicircular half annulus are simulated to illustrate general principles, especially the effects of vent curvature on deposition ring structure. Then two possible models for the giant plume Pele are presented. One is a curved line source corresponding to an IR image of a particularly hot region in the volcano's caldera and the other is a large area source corresponding to the entire caldera. The former is seen to produce the features seen in observations of Pele's ring, but with an error in orientation. The latter corrects the error in orientation, but loses some structure. A hybrid simulation of 3D slit flow is also discussed.Show more Item Simulation Of Plasma Interaction With Io's Atmosphere(2011-07) Moore, C. H.; Deng, H.; Goldstein, D. B.; Levin, D.; Varghese, P. L.; Trafton, L. M.; Stewart, B. D.; Walker, A. C.; Moore, Chris H.; Goldstein, David B.; Varghese, Philip L.; Trafton, Laurence M.; Stewart, Bénédicte D.; Walker, Andrew C.Show more One dimensional Direct Simulation Monte Carlo (DSMC) simulations are used to examine the interaction of the jovian plasma torus with Io's sublimation atmosphere. The hot plasma sweeps past Io at 57 km/s due to the external Jovian magnetic and corotational electric fields and the resultant energetic collisions both heat and dissociate the neutral gas creating an inflated, mixed atmosphere of SO(2) and its daughter products. The vertical structure and composition of the atmosphere is important for understanding Io's mass loading of the plasma torus, electron excited aurora, and Io's global gas dynamics. Our 1D simulations above a fixed location on the surface of Io allows the O(+) and S(+) ions to drift down into the domain where they then undergo elastic and charge exchange collisions with the neutral gas. Each electron's position is determined by the motion of a corresponding ion; however, the electrons retain their own velocity components which are then used during elastic, ionization, and excitation collisions with the neutral gas. Charge exchange creates fast neutral O and S atoms. Molecular Dynamic/Quasi-Classical Trajectory (MD/QCT) calculations are used to generate total and reaction cross sections for energetic O+SO(2) collisions [1] as well as for O+O(2) collisions. In addition, the model accounts for photo-dissociation assuming the atmosphere is optically thin. Our previous plasma heating model (without chemistry) agrees well with the vertical structure of the current model at lower altitudes where the gas is collisional; however, at high altitudes (>100 km) significant differences among the models appear. The current model's constant E and B fields results in reacceleration of the ions and electrons to a constant ExB drift velocity towards the surface after collisions with the neutral gas and, while the results are an upper limit on the plasma interaction strength, the results indicate that joule heating is significant, causing large changes in the vertical structure of the atmosphere. Plasma heating of, not momentum transfer to, the atmosphere dominates even for radially inward plasma flows resulting in a hot, inflated atmosphere. The scale heights for the various species were found to be a competition between the hydrodynamic scale height based on the gas constant (for the mixture if collisional) and the production rate from dissociation of SO(2) which depends on the local SO(2) density and available plasma energy at that altitude.Show more Item A Time Purified Separated Antiproton Beam At The AGS(1984) Bachman, M.; Barlett, M. L.; Bonner, B.; Borenstein, S.; Bridges, D.; Brown, H.; Buchanan, J.; Clement, J. C.; Daftari, I.; Debbe, R.; Deguzman, A.; Fergerson, R. W.; Flick, H.; Fickinger, W.; Gray, L.; Hoffman, G. W.; Hollas, C. L.; Kalogeropoulos, T.; Kruk, J.; Macasero, A.; Marino, R.; Mayes, B.; Milner, E. C.; Moss, R.; Mutchler, G. S.; Pinsky, L.; Riley, P. J.; Robinson, D. K.; Sakitt, M.; Skelly, J.; Tang, L. G.; Xu, S. W.; Xue, Y.; Bachman, M.; Bartlett, M.L.; Fergerson, R.W.; Hoffman, G.W.; Hollas, C.L.; Milner, E.C.; Ripley, P.J.; Xu, S.W.Show more Item Variance Reduction For A Discrete Velocity Gas(2011-07) Morris, A. B.; Varghese, P. L.; Goldstein, D. B.; Morris, A. B.; Varghese, P. L.; Goldstein, D. B.Show more We extend a variance reduction technique developed by Baker and Hadjiconstantinou [1] to a discrete velocity gas. In our previous work, the collision integral was evaluated by importance sampling of collision partners [2]. Significant computational effort may be wasted by evaluating the collision integral in regions where the flow is in equilibrium. In the current approach, substantial computational savings are obtained by only solving for the deviations from equilibrium. In the near continuum regime, the deviations from equilibrium are small and low noise evaluation of the collision integral can be achieved with very coarse statistical sampling. Spatially homogenous relaxation of the Bobylev-Krook-Wu distribution [3,4], was used as a test case to verify that the method predicts the correct evolution of a highly non-equilibrium distribution to equilibrium. When variance reduction is not used, the noise causes the entropy to undershoot, but the method with variance reduction matches the analytic curve for the same number of collisions. We then extend the work to travelling shock waves and compare the accuracy and computational savings of the variance reduction method to DSMC over Mach numbers ranging from 1.2 to 10.Show more Item Web Applet For Predicting Structure And Thermodynamics Of Complex Fluids(2015-03) Popp, Theodore R. III; Hollingshead, Kyle. B.; Truskett, Thomas M.; Popp, Theodore R. III; Hollingshead, Kyle. B.; Truskett, Thomas M.Show more Based on a recently introduced analytical strategy [Hollingshead et al., J. Chem. Phys. 139, 161102 (2013)], we present a web applet that can quickly and semi-quantitatively estimate the equilibrium radial distribution function and related thermodynamic properties of a fluid from knowledge of its pair interaction. We describe the applet's features and present two (of many possible) examples of how it can be used to illustrate concepts of interest for introductory statistical mechanics courses: the transition from ideal gas-like behavior to correlated-liquid behavior with increasing density, and the tradeoff between dominant length scales with changing temperature in a system with ramp-shaped repulsions. The latter type of interaction qualitatively captures distinctive thermodynamic properties of liquid water, because its energetic bias toward locally open structures mimics that of water's hydrogen-bond network. (C) 2015 American Association of Physics Teachers.Show more