Discrete Packet Analysis for Improved Atmospheric Rejection on Modulated Laser Signals
O'Neill, M., McKenna, I., DiBenedetto, J., Capelle, G., Trainham, R.
2012-07-19T23:59:59.000Z
This slide-show discusses how the method of discrete packet analysis improves atmospheric compensation for quasi-CW fluorescence detection methods. This is key to improving remote sensing capabilities.
Stephens, Britton B.
Strategies for measurement of atmospheric column means of carbon dioxide from aircraft using and Structure: Instruments and techniques; KEYWORDS: carbon dioxide, column mean, column integral, COBRA, flask, Strategies for measurement of atmospheric column means of carbon dioxide from aircraft using discrete
HYPERsensarium : an archive of atmospheric conditions
Shaw, Kelly E. (Kelly Evelyn)
2013-01-01T23:59:59.000Z
HYPERsensarium proposes a tangible interface of atmospheres for public experience through an archive of historical and projected weathers. While architecture's purpose has long been to act as the technical boundary between ...
, as giant planets should be warmest, largest, and brightest when they are young, but will cool, contractSYNTHETIC SPECTRA AND COLORS OF YOUNG GIANT PLANET ATMOSPHERES: EFFECTS OF INITIAL CONDITIONS 2008 March 17; accepted 2008 May 7 ABSTRACT We examine the spectra and infrared colors of the cool
Discrete Elements Method: A New Kind of Initial Conditions - Tetrahedral Packing of Balls
Mark A. Tsayger
2014-12-15T23:59:59.000Z
The Paper discusses the use of the regular packing of identical balls with the coordination number 4 as a model of a medium consisting of fluid and solid particles in the conditions of fluidization. It is proposed to use the examined packing of balls as an initial condition for the calculations by the Discrete Elements Method (DEM) in technological processes in the fluidized bed in industry, as well as in the modeling of processes that occur in hydraulic and pneumatic transport of granular materials. Filtration properties of such packing required for its use as an initial condition in calculations by DEM are estimated.
Standard 1D solar atmosphere as initial condition for MHD simulations and switch-on effects
Bourdin, Philippe-A
2015-01-01T23:59:59.000Z
Many applications in Solar physics need a 1D atmospheric model as initial condition or as reference for inversions of observational data. The VAL atmospheric models are based on observations and are widely used since decades. Complementary to that, the FAL models implement radiative hydrodynamics and showed the shortcomings of the VAL models since almost equally long time. In this work, we present a new 1D layered atmosphere that spans not only from the photosphere to the transition region, but from the solar interior up to far in the corona. We also discuss typical mistakes that are done when switching on simulations based on such an initial condition and show how the initial condition can be equilibrated so that a simulation can start smoothly. The 1D atmosphere we present here served well as initial condition for HD and MHD simulations and should also be considered as reference data for solving inverse problems.
Hively, Lee M.
2014-09-16T23:59:59.000Z
Data collected from devices and human condition may be used to forewarn of critical events such as machine/structural failure or events from brain/heart wave data stroke. By monitoring the data, and determining what values are indicative of a failure forewarning, one can provide adequate notice of the impending failure in order to take preventive measures. This disclosure teaches a computer-based method to convert dynamical numeric data representing physical objects (unstructured data) into discrete-phase-space states, and hence into a graph (structured data) for extraction of condition change.
Abreu, P.; /Lisbon, IST; Aglietta, M.; /Turin U. /INFN, Turin; Ahlers, M.; /Wisconsin U., Madison; Ahn, E.J.; /Fermilab; Albuquerque, I.F.M.; /Sao Paulo U.; Allard, D.; /APC, Paris; Allekotte, I.; /Buenos Aires, CONICET; Allen, J.; /New York U.; Allison, P.; /Ohio State U.; Almela, A.; /Natl. Tech. U., San Nicolas /Buenos Aires, CONICET; Alvarez Castillo, J.; /Mexico U., ICN /Santiago de Compostela U.
2012-01-01T23:59:59.000Z
Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargue and averaged monthly models, the utility of the GDAS data is shown.
OH-initiated oxidation of benzene Part I. Phenol formation under atmospheric conditions
OH-initiated oxidation of benzene Part I. Phenol formation under atmospheric conditions Rainer-radical initiated oxidation of benzene was studied in two simulation chambers: (1) the large-volume outdoor chamber-red spectroscopy (FTIR) were used to simultaneously measure phenol and benzene. The second study used only FTIR
Riordan, C.J.; Hulstrom, R.L.; Myers, D.R.
1990-08-01T23:59:59.000Z
The technology to detoxify hazardous wastes using ultraviolet (UV) solar radiation is being investigated by the DOE/SERI Solar Thermal Technology Program. One of the elements of the technology evaluation is the assessment and characterization of UV solar radiation resources available for detoxification processes. This report describes the major atmospheric variables that determine the amount of UV solar radiation at the earth's surface, and how the ratio of UV-to-total solar radiation varies with atmospheric conditions. These ratios are calculated from broadband and spectral solar radiation measurements acquired at SERI, and obtained from the literature on modeled and measured UV solar radiation. The following sections discuss the atmospheric effects on UV solar radiation and provide UV-to-total solar radiation ratios from published studies, as well as measured values from SERI's data. A summary and conclusions are also given.
Sulfur capture by oil shale ashes under atmospheric and pressurized FBC conditions
Yrjas, K.P.; Hupa, M. [Aabo Akademi Univ., Turku (Finland). Dept. of Chemical Engineering; Kuelaots, I.; Ots, A. [Tallinn Technical Univ. (Estonia). Thermal Engineering Dept.
1995-12-31T23:59:59.000Z
When oil shale contains large quantities of limestone, a significant auto-absorption of sulfur is possible under suitable conditions. The sulfur capture by oil shale ashes has been studied using a pressurized thermogravimetric apparatus. The chosen experimental conditions were typical for atmospheric and pressurized fluidized bed combustion. The Ca/S molar ratios in the two oil shales studied were 8 (Estonian) and 10 (Israeli). The samples were first burned in a gas atmosphere containing O{sub 2} and N{sub 2} (and CO{sub 2} if pressurized). After the combustion step, SO{sub 2} was added and sulfation started. The results with the oil shales were compared to those obtained with an oil shale cyclone ash from the Narva power plant in Estonia. In general, the results from the sulfur capture experiments under both atmospheric and pressurized conditions showed that the oil shale cannot only capture its own sulfur but also significant amounts of additional sulfur of another fuel if the fuels are mixed together. For example from the runs at atmospheric pressure, the conversion of CaO to CaSO{sub 4} was about 70% for Israeli oil shale and about 55% for Estonian oil shale (850 C). For the cyclone ash the corresponding conversion was about 20%. In comparison it could be mentioned that under the same conditions the conversions of natural limestones are about 30%. The reason the cyclone ash was a poor sulfur absorbent was probably due to its temperature history. In Narva the oil shale was burned at a significantly higher temperature (1,400 C) than was used in the experiments (750 C and 850 C). This caused the ash to sinter and the reactive surface area of the cyclone ash was therefore decreased.
Ellison, Stanley Lee
1969-01-01T23:59:59.000Z
, 96 percent of the available water has been depleted 25 Table 2. Some physical properties of Bienville loamy fine sand. Mechanical Depth anal sis Texture Sand Silt Clay Bulk Water retention sity 0. 1 15 atm. atm. Available water storage ca... for the debre~ of MASTER OF SCIFNCE May 19G9 Major Subject: Range Science LEAF WATER POTENTIAL IN P2'NUS TAEDA L. AS RELATED TO FLUCTUATING SOIL WATER AND ATMOSPHERIC CONDITIONS A Thesis by STANLEY LEE ELLISON Approved as to style and content by...
Persson, Ola
Group tower at SHEBA: Near-surface conditions and surface energy budget, J. Geophys. Res., 107(C10Measurements near the Atmospheric Surface Flux Group tower at SHEBA: Near-surface conditions and surface energy budget P. Ola G. Persson,1 Christopher W. Fairall,2 Edgar L. Andreas,3 Peter S. Guest,4
Harilal, S. S.
occur during the laser pulse in ns laser ablation, fs laser pulses are too short that these phenomena doComparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere Laser-induced breakdown spectroscopy Laser-produced plasma Plasma dynamics Femtosecond laser ablation
Nusinovich, Gregory S.; Kashyn, Dmytro G. [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States)] [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States); Tatematsu, Yoshinori; Idehara, Toshitaka [FIR Center, University of Fukui, Fukui 910-8507 (Japan)] [FIR Center, University of Fukui, Fukui 910-8507 (Japan)
2014-01-15T23:59:59.000Z
This study was motivated by a new concept of remote detection of concealed radioactive materials by using a high power terahertz (THz) wave beam, which can be focused in a small spot where the wave electric field exceeds the breakdown threshold. In the presence of seed electrons in such a volume, this focusing can initiate the avalanche breakdown. Typically, an ambient density of free electrons is assumed to be at the level of one particle per cubic centimeter. So, when a breakdown-prone volume is smaller than 1 cm{sup 3}, there should be significant difference between the breakdown rates in the case of presence of additional sources of ionization versus its absence. Since the flux density of gamma rays emitted by radioactive materials rapidly falls with the distance from the source, while the intensity of THz waves also decreases with the distance due to wave attenuation in the atmosphere, it is important to find an optimal location of the breakdown to be initiated for a given distance between a radioactive material and a THz antenna. This problem is analyzed in a given paper with the account for not only atmospheric attenuation of THz waves but also the air turbulence.
Tatarova, E.; Henriques, J.; Dias, A.; Ferreira, C. M. [Institute of Plasmas and Nuclear Fusion, Instituto Superior Técnico, Technical University of Lisbon (Portugal)] [Institute of Plasmas and Nuclear Fusion, Instituto Superior Técnico, Technical University of Lisbon (Portugal); Luhrs, C. C.; Phillips, J. [Department of Mechanical and Aerospace Engineering, Naval Postgraduate School, Monterey, California 93943 (United States)] [Department of Mechanical and Aerospace Engineering, Naval Postgraduate School, Monterey, California 93943 (United States); Abrashev, M. V. [Faculty of Physics, Sofia University, 1164 Sofia (Bulgaria)] [Faculty of Physics, Sofia University, 1164 Sofia (Bulgaria)
2013-09-23T23:59:59.000Z
Microwave atmospheric pressure plasmas driven by surface waves were used to synthesize graphene sheets from vaporized ethanol molecules carried through argon plasma. In the plasma, ethanol decomposes creating carbon atoms that form nanostructures in the outlet plasma stream, where external cooling/heating was applied. It was found that the outlet gas stream temperature plays an important role in the nucleation processes and the structural quality of the produced nanostructures. The synthesis of few layers (from one to five) graphene has been confirmed by high-resolution transmission electron microscopy. Raman spectral studies were conducted to determine the ratio of the 2D to G peaks (>2). Disorder D-peak to G-peak intensity ratio decreases when outlet gas stream temperature decreases.
Smith, C.; Brigmon, R.
2009-10-20T23:59:59.000Z
Legionnaires disease is a pneumonia caused by the inhalation of the bacterium Legionella pneumophila. The majority of illnesses have been associated with cooling towers since these devices can harbor and disseminate the bacterium in the aerosolized mist generated by these systems. Historically, Savannah River Site (SRS) cooling towers have had occurrences of elevated levels of Legionella in all seasons of the year and in patterns that are difficult to predict. Since elevated Legionella in cooling tower water are a potential health concern a question has been raised as to the best control methodology. In this work we analyze available chemical, biological, and atmospheric data to determine the best method or key parameter for control. The SRS 4Q Industrial Hygiene Manual, 4Q-1203, 1 - G Cooling Tower Operation and the SRNL Legionella Sampling Program, states that 'Participation in the SRNL Legionella Sampling Program is MANDATORY for all operating cooling towers'. The resulting reports include L. pneumophila concentration information in cells/L. L. pneumophila concentrations >10{sup 7} cells/L are considered elevated and unsafe so action must be taken to reduce these densities. These remedial actions typically include increase biocide addition or 'shocking'. Sometimes additional actions are required if the problem persists including increase tower maintenance (e.g. cleaning). Evaluation of 14 SRS cooling towers, seven water quality parameters, and five Legionella serogroups over a three-plus year time frame demonstrated that cooling tower water Legionella densities varied widely though out this time period. In fact there was no one common consistent significant variable across all towers. The significant factors that did show up most frequently were related to suspended particulates, conductivity, pH, and dissolved oxygen, not chlorine or bromine as might be expected. Analyses of atmospheric data showed that there were more frequent significant elevated Legionella concentrations when the dew point temperature was high--a summertime occurrence. However, analysis of the three years of Legionella monitoring data of the 14 different SRS Cooling Towers demonstrated that elevated concentrations are observed at all temperatures and seasons. The objective of this study is to evaluate the ecology of L. pneumophila including serogroups and population densities, chemical, and atmospheric data, on cooling towers at SRS to determine whether relationships exist among water chemistry, and atmospheric conditions. The goal is to more fully understand the conditions which inhibit or encourage L. pneumophila growth and supply this data and associated recommendations to SRS Cooling Tower personnel for improved management of operation. Hopefully this information could then be used to help control L. pneumophila growth more effectively in SRS cooling tower water.
Glen, Crystal
2012-02-14T23:59:59.000Z
or indirectly by serving as cloud condensation nuclei, soot is thought to have a significant warming effect through absorption. Like inorganic salts, soot may undergo atmospheric transformation through the vapor condensation of non-volatile gaseous species which...
Brandeis, Geneviève
for the condensation of a water ocean T. Lebrun1 , H. Massol1 , E. Chassefière1 , A. Davaille2 , E. Marcq3 , P. Sarda1-planet distance. Our results suggest that a steam atmosphere delays the end of the magma ocean phase by typically 1 Myr. Water vapor condenses to an ocean after 0.1 Myr, 1.5 Myr and 10 Myr for, respectively, Mars
Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.
2013-10-01T23:59:59.000Z
Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.
Li, Lee, E-mail: leeli@mail.hust.edu.cn; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electric and Electronic Engineering, HuaZhong University of Science and Technology (HUST), Wuhan 430074 (China)
2014-01-14T23:59:59.000Z
Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.
Probabilistic Calibration of a Discrete Particle Model
Zhang, Yanbei
2011-10-21T23:59:59.000Z
A discrete element model (DEM) capable of reproducing the mechanistic behavior of a triaxial compressive test performed on a Vosges sandstone specimen is presented considering similar experimental testing conditions and ...
R. L. Oldershaw
2007-12-19T23:59:59.000Z
The possibility that global discrete dilation invariance is a fundamental symmetry principle of nature is explored. If the discrete self-similarity observed in nature is exact, then the Principle of General Covariance needs to be broadened in order to accommodate this form of discrete conformal invariance, and a further generalization of relativity theory is required.
Farfan, E.; Jannik, T.
2011-10-01T23:59:59.000Z
When assessing the feasibility of remediation following the detonation of a radiological dispersion device or improvised nuclear device in a large city, several issues should be considered including the levels and characteristics of the radioactive contamination, the availability of resources required for decontamination, and the planned future use of the city's structures and buildings. Currently, little is known about radionuclide penetration into construction materials in an urban environment. Knowledge in this area would be useful when considering costs of a thorough decontamination of buildings, artificial structures, and roads in an affected urban environment. Pripyat, a city substantially contaminated by the Chernobyl Nuclear Power Plant accident in April 1986, may provide some answers. The main objective of this study was to assess the depth of {sup 90}Sr and {sup 137}Cs penetration into reinforced concrete structures in a highly contaminated urban environment under natural weather conditions. Thirteen reinforced concrete core samples were obtained from external surfaces of a contaminated building in Pripyat. The concrete cores were drilled to obtain sample layers of 0-5, 5-10, 10-15, 15-20, 20-30, 30-40, and 40-50 mm. Both {sup 90}Sr and {sup 137}Cs were detected in the entire 0-50 mm profile of the reinforced cores sampled. In most of the cores, over 90% of the total {sup 137}Cs inventory and 70% of the total {sup 90}Sr inventory was found in the first 0-5 mm layer of the reinforced concrete. {sup 90}Sr had penetrated markedly deeper into the reinforced concrete structures than {sup 137}Cs.
Prathap, C.; Ray, Anjan; Ravi, M.R. [Department of Mechanical Engineering, Indian Institute of Technology, Delhi, New Delhi 110016 (India)
2008-10-15T23:59:59.000Z
The objective of this investigation was to study the effect of dilution with nitrogen on the laminar burning velocity and flame stability of syngas fuel (50% H{sub 2}-50% CO by volume)-air (21% O{sub 2}-79% N{sub 2} by volume) mixtures. The syngas fuel composition considered in this work comprised x% N{sub 2} by volume and (100-x)% an equimolar mixture of CO and H{sub 2}. The proportion x (i.e., %N{sub 2}) was varied from 0 to 60% while the H{sub 2}/CO ratio was always kept as unity. Spherically expanding flames were generated by centrally igniting homogeneous fuel-air gas mixtures in a 40-L cylindrical combustion chamber fitted with optical windows. Shadowgraphy technique with a high-speed imaging camera was used to record the propagating spherical flames. Unstretched burning velocity was calculated following the Karlovitz theory for weakly stretched flames. Also, Markstein length was calculated to investigate the flame stability conditions for the fuel-air mixtures under consideration. Experiments were conducted for syngas fuel with different nitrogen proportions (0-60%) at 0.1 MPa (absolute), 302{+-}3K, and equivalence ratios ranging from 0.6 to 3.5. All the measurements were compared with the numerical predictions obtained using RUN-1DL and PREMIX with a contemporary chemical kinetic scheme. Dilution with nitrogen in different proportions in syngas resulted in (a) decrease in laminar burning velocity due to reduction in heat release and increase in heat capacity of unburned gas mixture and hence the flame temperature, (b) shift in occurrence of peak laminar burning velocity from {phi}=2.0 for 0% N{sub 2} dilution to {phi}=1.4 for 60% N{sub 2} dilution, (c) augmentation of the coupled effect of flame stretch and preferential diffusion on laminar burning velocity, and (d) shift in the equivalence ratio for transition from stable to unstable flames from {phi}=0.6 for 0% N{sub 2} dilution to {phi}=1.0 for 60% N{sub 2} dilution. The present work also indicated that if the fuel mole fraction in the wide range of fuel-air mixtures investigated is less than 22%, then those fuel mixtures are in the unstable regime with regard to preferential diffusion. (author)
Daniels, Megan Hanako
2010-01-01T23:59:59.000Z
groundwater, land-surface, and mesoscale atmospheric model-and modification of mesoscale circulations. , Mon. Wea.J. Davis, The effects of mesoscale surface heterogeneity on
Atmospheric optical calibration system
Hulstrom, R.L.; Cannon, T.W.
1988-10-25T23:59:59.000Z
An atmospheric optical calibration system is provided to compare actual atmospheric optical conditions to standard atmospheric optical conditions on the basis of aerosol optical depth, relative air mass, and diffuse horizontal skylight to global horizontal photon flux ratio. An indicator can show the extent to which the actual conditions vary from standard conditions. Aerosol scattering and absorption properties, diffuse horizontal skylight to global horizontal photon flux ratio, and precipitable water vapor determined on a real-time basis for optical and pressure measurements are also used to generate a computer spectral model and for correcting actual performance response of a photovoltaic device to standard atmospheric optical condition response on a real-time basis as the device is being tested in actual outdoor conditions. 7 figs.
Atmospheric optical calibration system
Hulstrom, Roland L. (Bloomfield, CO); Cannon, Theodore W. (Golden, CO)
1988-01-01T23:59:59.000Z
An atmospheric optical calibration system is provided to compare actual atmospheric optical conditions to standard atmospheric optical conditions on the basis of aerosol optical depth, relative air mass, and diffuse horizontal skylight to global horizontal photon flux ratio. An indicator can show the extent to which the actual conditions vary from standard conditions. Aerosol scattering and absorption properties, diffuse horizontal skylight to global horizontal photon flux ratio, and precipitable water vapor determined on a real-time basis for optical and pressure measurements are also used to generate a computer spectral model and for correcting actual performance response of a photovoltaic device to standard atmospheric optical condition response on a real-time basis as the device is being tested in actual outdoor conditions.
A discrete fractional random transform
Zhengjun Liu; Haifa Zhao; Shutian Liu
2006-05-20T23:59:59.000Z
We propose a discrete fractional random transform based on a generalization of the discrete fractional Fourier transform with an intrinsic randomness. Such discrete fractional random transform inheres excellent mathematical properties of the fractional Fourier transform along with some fantastic features of its own. As a primary application, the discrete fractional random transform has been used for image encryption and decryption.
Discrete Fourier Transform Javier Montoya
Giger, Christine
Discrete Fourier Transform Javier Montoya Photogrammetry and Remote Sensing ETH Zurich March 16, 2012 1 Introduction The Discrete form of the Fourier transform is known as Discrete Fourier Transform domain using the Inverse Discrete Fourier Transform (IDFT): f(x) = 1 N N-1 x=0 F(u)ej 2 N ux for u = 0, 1
Jaquin, R.F.
1989-01-01T23:59:59.000Z
Profiles of scattered light above the planetary limb from 116 Viking Orbiter images are used to constrain the temporal and spatial behavior of aerosols suspended in the Martian atmosphere. The data cover a wide range of seasons, locations, and viewing geometry, providing information about the aerosol optical properties and vertical distribution. The typical atmospheric column contains one or more discrete, optically thin, ice-like haze layers between 30 and 90 km elevation whose composition is inferred to be water ice. Below the detached hazes, a continuous haze, interpreted to have a large dust component, extends from as much as 50 km to the surface. The haze distribution exhibits an annual variation that reflects a seasonally driven circulation in the middle atmosphere. The potential role of stationary gravity waves in modifying the middle atmosphere circulation is explored using a linear theory applied to a realistic Martian environment. Martian topography derived from radar observations is decomposed into Fourier harmonics and used to linearly superpose gravity waves arising from each component. The larger amplitude topography on Mars combined with the absence of extended regions of smooth topography like oceans generates larger wave amplitudes than on the Earth. The circulation of the middle atmosphere is examined using a two-dimensional, linearized, axisymmetric model successfully employed in the study of the terrestrial mesosphere. Illustrations of temperature and wind speeds are presented for the southern summer solstice and southern spring equinox.
Discrete multivariate distributions
Oleg Yu. Vorobyev; Lavrentiy S. Golovkov
2011-02-22T23:59:59.000Z
This article brings in two new discrete distributions: multidimensional Binomial distribution and multidimensional Poisson distribution. Those distributions were created in eventology as more correct generalizations of Binomial and Poisson distributions. Accordingly to eventology new laws take into account full distribution of events. Also, in article its characteristics and properties are described
Differential Geometry: Discrete Exterior Calculus
Kazhdan, Michael
Differential Geometry: Discrete Exterior Calculus [Build Your Own DEC at Home. Elcott et al., 2006] [Discrete Differential Forms for Computational Modeling. Desbrun et al., 2005] [Discrete Exterior Calculus-simplices in : where c is a real-valued function. The space of k-chains is denoted Ck(). = k cc )( #12;Chains
L. R. G. Fontes; C. M. Newman; K. Ravishankar; E. Schertzer
2007-04-20T23:59:59.000Z
The dynamical discrete web (DDW), introduced in recent work of Howitt and Warren, is a system of coalescing simple symmetric one-dimensional random walks which evolve in an extra continuous dynamical parameter s. The evolution is by independent updating of the underlying Bernoulli variables indexed by discrete space-time that define the discrete web at any fixed s. In this paper, we study the existence of exceptional (random) values of s where the paths of the web do not behave like usual random walks and the Hausdorff dimension of the set of such exceptional s. Our results are motivated by those about exceptional times for dynamical percolation in high dimension by H\\"aggstrom, Peres and Steif, and in dimension two by Schramm and Steif. The exceptional behavior of the walks in DDW is rather different from the situation for dynamical random walks of Benjamini, H\\"aggstrom, Peres and Steif. In particular, we prove that there are exceptional values of s for which the walk from the origin S^s(n) has limsup S^s(n)/\\sqrt n \\leq K with a nontrivial dependence of the Hausdorff dimension on K. We also discuss how these and other results extend to the dynamical Brownian web, a natural scaling limit of DDW. The scaling limit is the focus of a paper in preparation; it was studied by Howitt and Warren and is related to the Brownian net of Sun and Swart.
Hirsch, M.; Morisi, S.; Peinado, E.; Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apartado 22085, E-46071 Valencia (Spain)
2010-12-01T23:59:59.000Z
We propose a new motivation for the stability of dark matter (DM). We suggest that the same non-Abelian discrete flavor symmetry which accounts for the observed pattern of neutrino oscillations, spontaneously breaks to a Z{sub 2} subgroup which renders DM stable. The simplest scheme leads to a scalar doublet DM potentially detectable in nuclear recoil experiments, inverse neutrino mass hierarchy, hence a neutrinoless double beta decay rate accessible to upcoming searches, while {theta}{sub 13}=0 gives no CP violation in neutrino oscillations.
Discrete Probability Distributions
Stewart, William J.
, 2, . . . , n, the moments of the discrete uniform distribution are given by E[Xk ] = nX i=1 ik /n. In particular, E[X] = nX i=1 i/n = 1 n nX i=1 i = 1 n n(n + 1) 2 = n + 1 2 , and, using the well-known formula for the sum of the squares of the first n integers, E[X2 ] = nX i=1 i2 /n = 1 n nX i=1 i2 = 1 n n(n + 1)(2n
Thomas K. Gaisser
2006-12-11T23:59:59.000Z
This paper is a brief overview of the theory and experimental data of atmospheric neutrino production at the fiftieth anniversary of the experimental discovery of neutrinos.
Thermodynamics of discrete quantum processes
Janet Anders; Vittorio Giovannetti
2012-11-01T23:59:59.000Z
We define thermodynamic configurations and identify two primitives of discrete quantum processes between configurations for which heat and work can be defined in a natural way. This allows us to uncover a general second law for any discrete trajectory that consists of a sequence of these primitives, linking both equilibrium and non-equilibrium configurations. Moreover, in the limit of a discrete trajectory that passes through an infinite number of configurations, i.e. in the reversible limit, we recover the saturation of the second law. Finally, we show that for a discrete Carnot cycle operating between four configurations one recovers Carnot's thermal efficiency.
Constucting Discrete KSurfaces Ivan Sterling
Sterling, Ivan
Constucting Discrete KSurfaces Ivan Sterling (joint work with Tim Ho#mann, and Ulrich Pinkall) Old it is possible to find other examples (FIGURE 4). 2 #12; Figure 4. Ho#manSterling Discrete KSurface 4. Computer and examples can be found at www.jreality.de. References [1] G.T. Bennett, A new mechanism, Engineering 76
Note on Discrete Gauge Anomalies
T. Banks; M. Dine
1991-10-02T23:59:59.000Z
We consider the probem of gauging discrete symmetries. All valid constraints on such symmetries can be understood in the low energy theory in terms of instantons. We note that string perturbation theory often exhibits global discrete symmetries, which are broken non-perturbatively.
Environmental Conditions Environmental Conditions
Environmental Conditions Environmental Conditions Appendix II The unique geology, hydrology and instream habitat. This chapter examines how environmental conditions in the Deschutes watershed affect, the discussion characterizes the environmental conditions within three watershed areas: the Lower Deschutes
FPGA Acceleration of Discrete Molecular Dynamics Simulation
Herbordt, Martin
' & $ % FPGA Acceleration of Discrete Molecular Dynamics Simulation Joshua Model Thesis submitted UNIVERSITY COLLEGE OF ENGINEERING Thesis FPGA Acceleration of Discrete Molecular Dynamics Simulation Acceleration of Discrete Molecular Dynamics Simulation Joshua Model ABSTRACT Molecular dynamics simulation
System for time-discretized vacuum ultraviolet spectroscopy of spark breakdown in air
Ryberg, D.; Fierro, A.; Dickens, J.; Neuber, A. [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States)
2014-10-15T23:59:59.000Z
A system for time-discretized spectroscopic measurements of the vacuum ultraviolet (VUV) emission from spark discharges in the 60-160 nm range has been developed for the study of early plasma-forming phenomena. The system induces a spark discharge in an environment close to atmospheric conditions created using a high speed puff value, but is otherwise kept at high vacuum to allow for the propagation of VUV light. Using a vertical slit placed 1.5 mm from the discharge the emission from a small cross section of the discharge is allowed to pass into the selection chamber consisting of a spherical grating, with 1200 grooves/mm, and an exit slit set to 100 ?m. Following the exit slit is a photomultiplier tube with a sodium salicylate scintillator that is used for the time discretized measurement of the VUV signal with a temporal resolution limit of 10 ns. Results from discharges studied in dry air, Nitrogen, SF{sub 6}, and Argon indicate the emission of light with wavelengths shorter than 120 nm where the photon energy begins to approach the regime of direct photoionization.
Discrete sine-Gordon dynamics on networks
Dutykh, Denys
2015-01-01T23:59:59.000Z
In this study we consider the sine-Gordon equation formulated on domains which are not locally homeomorphic to any subset of the Euclidean space. More precisely, we formulate the discrete dynamics on trees and graphs. Each edge is assumed to be a 1D uniform lattice with end points identified with graph vertices. A special treatment is needed at the junctions in order to couple 1D lattices into a global communicating network. Our approach is based on considering the local conservation properties. Some preliminary numerical results are shown on a simple graph containing four loops. These results show the performance of the scheme in non-trivial realistic conditions.
International Symposium on Discrete Mathematics
University, China Ghent University, Belgium CAS-MPG Partner Institute for Computational Biology, ChinaInternational Symposium on Discrete Mathematics and Mathematical Biology August 2627, 2013 Find Interdisciplinary Centre for Bioinformatics #12;
Presented by Parallel Discrete Event Simulation
of discrete event execution on high performance computing Business Sensitive · Different optimizations
Tensile damage response from discrete element virtual testing
Paris-Sud XI, Université de
Tensile damage response from discrete element virtual testing A. DELAPLACE LMT-Cachan, ENS Cachan conditions on brittle materials, damage can generally not be re- duced to a simple scalar. Microcrack into account the damage anisotropy in phenomenological models is a possible option, but the identification
Raman, Sethu
, and Atmospheric Sciences, North Carolina State University, Suite 240, Research III Building, 1005 Capability Drive energy budget located throughout Oklahoma City. Three wind-profiling radars were used to measure wind with observed mixing heights measured during Joint URBAN 2003. Observed CBL heights are derived from profiler
Atmospheric Aerosols Workshop | EMSL
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Atmospheric Aerosols Workshop Atmospheric Aerosols Workshop EMSL Science Theme Advisory Panel Workshop - Atmospheric Aerosol Chemistry, Climate Change, and Air Quality. Baer DR, BJ...
Discrete Hamiltonian for General Relativity
Ziprick, Jonathan
2015-01-01T23:59:59.000Z
Beginning from canonical general relativity written in terms of Ashtekar variables, we derive a discrete phase space with a physical Hamiltonian for gravity. The key idea is to define the gravitational fields within a complex of three-dimensional cells such that the dynamics is completely described by discrete boundary variables, and the full theory is recovered in the continuum limit. Canonical quantization is attainable within the loop quantum gravity framework, and we believe this will lead to a promising candidate for quantum gravity.
Discrete Hamiltonian for General Relativity
Jonathan Ziprick; Jack Gegenberg
2015-07-27T23:59:59.000Z
Beginning from canonical general relativity written in terms of Ashtekar variables, we derive a discrete phase space with a physical Hamiltonian for gravity. The key idea is to define the gravitational fields within a complex of three-dimensional cells such that the dynamics is completely described by discrete boundary variables, and the full theory is recovered in the continuum limit. Canonical quantization is attainable within the loop quantum gravity framework, and we believe this will lead to a promising candidate for quantum gravity.
Quantum chaos on discrete graphs
Uzy Smilansky
2007-04-26T23:59:59.000Z
Adapting a method developed for the study of quantum chaos on {\\it quantum (metric)} graphs \\cite {KS}, spectral $\\zeta$ functions and trace formulae for {\\it discrete} Laplacians on graphs are derived. This is achieved by expressing the spectral secular equation in terms of the periodic orbits of the graph, and obtaining functions which belongs to the class of $\\zeta$ functions proposed originally by Ihara \\cite {Ihara}, and expanded by subsequent authors \\cite {Stark,Sunada}. Finally, a model of "classical dynamics" on the discrete graph is proposed. It is analogous to the corresponding classical dynamics derived for quantum graphs \\cite {KS}.
ENVIRONMENTAL CONDITIONS INFLUENCE ON EMBEDDED CAPACITORS -COMPARISON WITH DISCRETE CAPACITORS
Boyer, Edmond
. Polymer-ceramic composites are expected to be the major candidate as dielectric interlayer for embedded of early failures peculiar to ceramic capacitors, technologists are using new polymer-ceramic materials is caused by the mismatch of the thermal expansion coefficient and the thermal conductivity between
Gunzburger, Max
2013-03-12T23:59:59.000Z
The work reported is in pursuit of these goals: high-quality unstructured, non-uniform Voronoi and Delaunay grids; improved finite element and finite volume discretization schemes; and improved finite element and finite volume discretization schemes. These are sought for application to spherical and three-dimensional applications suitable for ocean, atmosphere, ice-sheet, and other climate modeling applications.
Software is Discrete Mathematics University of Oklahoma
Page, Rex L.
, discrete mathematics, predicate logic, correctness proofs, formal methods, software engineering. 1Software is Discrete Mathematics Rex L Page University of Oklahoma School of Computer Science Descriptors D.2.4 [Software Engineering]: Software/Program Verification correctness proofs, formal methods
Discrete and Hybrid Nonholonomy Antonio Bicchi1
Piccoli, Benedetto
Discrete and Hybrid Nonholonomy Antonio Bicchi1 , Alessia Marigo2 , and Benedetto Piccoli3 1 Centro such as cars, trucks with trailers, rolling 3D objects, underactuated mechanisms, satellites, etc., has made of systems, allowing for discrete and hybrid (mixed continuous and discrete) configurations and transi- tions
INTRODUCTIONTOTHE SOLAR ATMOSPHERE
? #12;WHAT ISTHE SOLAR ATMOSPHERE? #12;#12;1-D MODEL ATMOSPHERE · Averaged over space and time · GoodINTRODUCTIONTOTHE SOLAR ATMOSPHERE D. Shaun Bloomfield Trinity College Dublin #12;OUTLINE · What is the solar atmosphere? · How is the solar atmosphere observed? · What structures exist and how do they evolve
Yoon, Joon Sik, 1973-
2005-01-01T23:59:59.000Z
An understanding of how discrete particles in the micron to submicron range behave in porous media is important to a number of environmental problems. Discrete particle behavior in the interior of a porous medium is complex ...
Fast Computation Algorithm for Discrete Resonances among Gravity Waves
Elena Kartashova
2006-05-25T23:59:59.000Z
Traditionally resonant interactions among short waves, with large real wave-numbers, were described statistically and only a small domain in spectral space with integer wave-numbers, discrete resonances, had to be studied separately in resonators. Numerical simulations of the last few years showed unambiguously the existence of some discrete effects in the short-waves part of the wave spectrum. Newly presented model of laminated turbulence explains theoretically appearance of these effects thus putting a novel problem - construction of fast algorithms for computation of solutions of resonance conditions with integer wave-numbers of order $10^3$ and more. Example of such an algorithm for 4-waves interactions of gravity waves is given. Its generalization on the different types of waves is briefly discussed.
Invariant discretization schemes for the shallow-water equations
Alexander Bihlo; Roman O. Popovych
2013-01-03T23:59:59.000Z
Invariant discretization schemes are derived for the one- and two-dimensional shallow-water equations with periodic boundary conditions. While originally designed for constructing invariant finite difference schemes, we extend the usage of difference invariants to allow constructing of invariant finite volume methods as well. It is found that the classical invariant schemes converge to the Lagrangian formulation of the shallow-water equations. These schemes require to redistribute the grid points according to the physical fluid velocity, i.e., the mesh cannot remain fixed in the course of the numerical integration. Invariant Eulerian discretization schemes are proposed for the shallow-water equations in computational coordinates. Instead of using the fluid velocity as the grid velocity, an invariant moving mesh generator is invoked in order to determine the location of the grid points at the subsequent time level. The numerical conservation of energy, mass and momentum is evaluated for both the invariant and non-invariant schemes.
Autumn 2014 Atmospheric Circulation
Doty, Sharon Lafferty
to perform atmospheric chemistry measurements in this remote region of ubiquitous oil and gas drilling the hypothesisofsnowchemistrybeinganimportant contributor to the ozone problem in Utah during the Atmospheric Chemistry Gordon ConferenceAutumn 2014 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences
Quasicrystals with discrete support and spectrum
Nir Lev; Alexander Olevskii
2015-09-08T23:59:59.000Z
We proved recently that a measure on R, whose support and spectrum are both uniformly discrete sets, must have a periodic structure. Here we show that this is not the case if the support and the spectrum are just discrete closed sets.
Discrete R Symmetries and Low Energy Supersymmetry
California at Santa Cruz, University of
R Symmetries and Low Energy Supersymmetry #12;Plan for Today: "New, Improved" Models of DynamicalDiscrete R Symmetries and Low Energy Supersymmetry UC Davis, 2011 Michael Dine Department on metastable susy breaking. Michael Dine Discrete R Symmetries and Low Energy Supersymmetry #12;Metastable
Identification and Estimation of a Discrete Game of Complete Information
Bajari, Patrick
We discuss the identification and estimation of discrete games of complete information. Following Bresnahan and Reiss (1990, 1991), a discrete game is a generalization of a standard discrete choice model where utility ...
COHERENT DISCRETE EMBEDDINGS FOR LAGRANGIAN AND HAMILTONIAN SYSTEMS
COHERENT DISCRETE EMBEDDINGS FOR LAGRANGIAN AND HAMILTONIAN SYSTEMS by J. Cresson, I. Greff & C . . ........................................ 6 Part II. Discrete variational embedding of Lagrangian systems . . ...................... 7 4. -- Lagrangian systems, Hamiltonian systems, variational integrators, discrete embeddings, numerical schemes, FEM
Ken-ichi Maruno; Gino Biondini
2005-04-09T23:59:59.000Z
We present a class of solutions of the two-dimensional Toda lattice equation, its fully discrete analogue and its ultra-discrete limit. These solutions demonstrate the existence of soliton resonance and web-like structure in discrete integrable systems such as differential-difference equations, difference equations and cellular automata (ultra-discrete equations).
Discrete Symmetry and Stability in Hamiltonian Dynamics
Tassos Bountis; George Chechin; Vladimir Sakhnenko
2010-05-31T23:59:59.000Z
In this tutorial we address the existence and stability of periodic and quasiperiodic orbits in N degree of freedom Hamiltonian systems and their connection with discrete symmetries. Of primary importance in our study are the nonlinear normal modes (NNMs), i.e periodic solutions which represent continuations of the system's linear normal modes in the nonlinear regime. We examine the existence of such solutions and discuss different methods for constructing them and studying their stability under fixed and periodic boundary conditions. In the periodic case, we employ group theoretical concepts to identify a special type of NNMs called one-dimensional "bushes". We describe how to use linear combinations such NNMs to construct s(>1)-dimensional bushes of quasiperiodic orbits, for a wide variety of Hamiltonian systems and exploit the symmetries of the linearized equations to simplify the study of their destabilization. Applying this theory to the Fermi Pasta Ulam (FPU) chain, we review a number of interesting results, which have appeared in the recent literature. We then turn to an analytical and numerical construction of quasiperiodic orbits, which does not depend on the symmetries or boundary conditions. We demonstrate that the well-known "paradox" of FPU recurrences may be explained in terms of the exponential localization of the energies Eq of NNM's excited at the low part of the frequency spectrum, i.e. q=1,2,3,.... Thus, we show that the stability of these low-dimensional manifolds called q-tori is related to the persistence or FPU recurrences at low energies. Finally, we discuss a novel approach to the stability of orbits of conservative systems, the GALIk, k=2,...,2N, by means of which one can determine accurately and efficiently the destabilization of q-tori, leading to the breakdown of recurrences and the equipartition of energy, at high values of the total energy E.
Discrete Fourier-based Correlations for Entanglement Detection
Ryo Namiki; Yuuki Tokunaga
2012-06-06T23:59:59.000Z
We introduce two forms of correlations on two $d$-level (qudit) systems for entanglement detection. The correlations can be measured via experimentally tractable two local measurement settings and their separable bounds are determined by discrete Fourier-based uncertainty relations. They are useful to estimate lower bounds of the Schmidt number in order to clarify generation of a genuine qudit entanglement. We also present inseparable conditions for multi-qudit systems associated with the qudit stabilizer formalism as another role of the correlations on the inseparability problem.
Atmospheric Transport of Radionuclides
Crawford, T.V.
2003-03-03T23:59:59.000Z
The purpose of atmospheric transport and diffusion calculations is to provide estimates of concentration and surface deposition from routine and accidental releases of pollutants to the atmosphere. This paper discusses this topic.
Atmospheric sampling glow discharge ionization source
McLuckey, S.A.; Glish, G.L.
1989-07-18T23:59:59.000Z
An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.
Atmospheric chemistry and global change
Prather, MJ
1999-01-01T23:59:59.000Z
and particles. Thus Atmospheric Chemistry and Global Changethe future of atmospheric chemistry. BROWSINGS Tornadothe complexity of atmospheric chemistry well, but trips a
Atmospheric Pressure Reactor System | EMSL
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Atmospheric Pressure Reactor System Atmospheric Pressure Reactor System The atmospheric pressure reactor system is designed for testing the efficiency of various catalysts for the...
ATMOSPHERIC CHEMISTRY AND PHYSICS
Brandenburg, Axel
ATMOSPHERIC CHEMISTRY AND PHYSICS From Air Pollution to Climate Change SECOND EDITION John H-in-Publication Data: Seinfeld, John H. Atmospheric chemistry and physics : from air pollution to climate change / John: 978-0-471-72018-8 (paper) ISBN-10: 0-471-72018-6 (paper) 1. Atmospheric chemistry. 2. Air
Climate Sciences: Atmospheric Thermodynamics
Russell, Lynn
1 Climate Sciences: Atmospheric Thermodynamics Instructor: Lynn Russell, NH343 http://aerosol.ucsd.edu/courses.html Text: Curry & Webster Atmospheric Thermodynamics Ch1 Composition Ch2 Laws Ch3 Transfers Ch12 Energy Climate Sciences: Atmospheric Thermodynamics Instructor: Lynn Russell, NH343 http
Xiaoning Wu
2006-06-06T23:59:59.000Z
In this paper, we consider the discrete AKNS-D hierarchy, find the construction of the hierarchy, prove the bilinear identity and give the construction of the $\\tau$-functions of this hierarchy.
Spatially Discrete FitzHugh-Nagumo Equations
Elmer, Christopher E.; Van Vleck, Erik
2005-04-05T23:59:59.000Z
We consider pulse and front solutions to a spatially discrete FitzHugh--Nagumo equation that contains terms to represent both depolarization and hyperpolarization of the nerve axon. We demonstrate a technique for deriving ...
Discrete element modelling of cementitious materials
Brown, Nicholas John
2013-07-01T23:59:59.000Z
This thesis presents a new bonded particle model that accurately predicts the wideranging behaviour of cementitious materials. There is an increasing use of the Discrete Element Method (DEM) to study the behaviour of ...
Symmetric Instantons and Discrete Hitchin Equations
Ward, R S
2015-01-01T23:59:59.000Z
Self-dual Yang-Mills instantons on $R^4$ correspond to algebraic ADHM data. This paper describes how to specialize such ADHM data so that the instantons have a $T^2$ symmetry, and this in turn motivates an integrable discrete version of the 2-dimensional Hitchin equations. It is analogous to the way in which the ADHM data for $S^1$-symmetric instantons, or hyperbolic BPS monopoles, may be viewed as a discretization of the Nahm equations.
Terrestrial Planet Atmospheres. The Moon's Sodium Atmosphere
Walter, Frederick M.
;Origins of Atmospheres · Outgassing Volcanoes expel water, CO2, N2, H2S, SO2 removed by the Fme convecFon reaches deserts #12;Water and Ice Clouds #12;H2SO4
Atmospheric,OceanicandSpaceSciences Atmospheric, Oceanic & Space Sciences
Eustice, Ryan
Areas Atmosphere Biosphere Interactions Atmospheric Chemistry, Aerosols & Air Quality Atmospheric05/14 4.0 Atmospheric,OceanicandSpaceSciences Atmospheric, Oceanic & Space Sciences UniversityGraduate (SGuS) ProGram (BSe & menG in 5 yearS) Space Engineering ReSearch areaS Atmospheric Science Research
Energy Levels of "Hydrogen Atom" in Discrete Time Dynamics
Andrei Khrennikov; Yaroslav Volovich
2006-04-27T23:59:59.000Z
We analyze dynamical consequences of a conjecture that there exists a fundamental (indivisible) quant of time. In particular we study the problem of discrete energy levels of hydrogen atom. We are able to reconstruct potential which in discrete time formalism leads to energy levels of unperturbed hydrogen atom. We also consider linear energy levels of quantum harmonic oscillator and show how they are produced in the discrete time formalism. More generally, we show that in discrete time formalism finite motion in central potential leads to discrete energy spectrum, the property which is common for quantum mechanical theory. Thus deterministic (but discrete time!) dynamics is compatible with discrete energy levels.
Green's function of a finite chain and the discrete Fourier transform
S. Cojocaru
2007-04-22T23:59:59.000Z
A new expression for the Green's function of a finite one-dimensional lattice with nearest neighbor interaction is derived via discrete Fourier transform. Solution of the Heisenberg spin chain with periodic and open boundary conditions is considered as an example. Comparison to Bethe ansatz clarifies the relation between the two approaches.
ERROR ESTIMATES FOR A TIME DISCRETIZATION METHOD FOR THE RICHARDS' EQUATION
Eindhoven, Technische Universiteit
. The continuity condition t() + · (q) = 0 combined with Darcy law (1.1) leads to Richards' equation (1.2) tERROR ESTIMATES FOR A TIME DISCRETIZATION METHOD FOR THE RICHARDS' EQUATION IULIU SORIN POP' equation. Written in its saturation-based form, this nonlinear para- bolic equation models water flow
Mortar finite element discretization of a model coupling Darcy and Stokes equations
Boyer, Edmond
Mortar finite element discretization of a model coupling Darcy and Stokes equations by C. Bernardi1 flowing on a homogeneous porous ground, we consider a system where the Darcy and Stokes equations´erons un syst`eme o`u les ´equations de Darcy et de Stokes sont coupl´ees par des conditions de raccord
Irreducibility and co-primeness as an integrability criterion for discrete equations
Masataka Kanki; Jun Mada; Takafumi Mase; Tetsuji Tokihiro
2014-10-17T23:59:59.000Z
We study the Laurent property, the irreducibility and co-primeness of discrete integrable and non-integrable equations. First we study a discrete integrable equation related to the Somos-4 sequence, and also a non-integrable equation as a comparison. We prove that the conditions of irreducibility and co-primeness hold only in the integrable case. Next, we generalize our previous results on the singularities of the discrete Korteweg-de Vries (dKdV) equation. In our previous paper (arXiv:1311.0060), we described the singularity confinement test (one of the integrability criteria) using the Laurent property, and the irreducibility, and co-primeness of the terms in the bilinear dKdV equation, in which we only considered simplified boundary conditions. This restriction was needed to obtain simple (monomial) relations between the bilinear form and the nonlinear form of the dKdV equation. In this paper, we prove the co-primeness of the terms in the nonlinear dKdV equation for general initial conditions and boundary conditions, by using the localization of Laurent rings and the interchange of the axes. We assert that co-primeness of the terms can be used as a new integrability criterion, which is a mathematical re-interpretation of the confinement of singularities in the case of discrete equations. v2, v3: minor revisions
Thomas K. Gaisser
2005-02-18T23:59:59.000Z
Starting with an historical review, I summarize the status of calculations of the flux of atmospheric neutrinos and how they compare to measurements.
EMSL - Atmospheric Aerosol Systems
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
iogenic-anthropogenic interactions on the physical and chemical properties of atmospheric organic aerosols, PI-Sergey Nizkorodov, University of California at Irvine
Heterogeneous Surface-Based Freezing of Atmospheric Aerosols Containing Ash, Soot, and Soil
Fornea, Adam P.
2010-07-14T23:59:59.000Z
Nucleation of ice crystals in the atmosphere often occurs through heterogeneous freezing processes facilitated by an atmospheric aerosol that acts as the ice nuclei (IN). Depending on ambient conditions and aerosol composition, heterogeneous...
Heterogeneous Surface-Based Freezing of Atmospheric Aerosols Containing Ash, Soot, and Soil
Fornea, Adam P.
2010-07-14T23:59:59.000Z
Nucleation of ice crystals in the atmosphere often occurs through heterogeneous freezing processes facilitated by an atmospheric aerosol that acts as the ice nuclei (IN). Depending on ambient conditions and aerosol composition, heterogeneous...
Atmospheric Dynamics II Instructor
AT602 Atmospheric Dynamics II 2 credits Instructor: David W. J. Thompson davet: An Introduction to Dynamic Meteorology, 5th Edition, Academic Press (recommended) · Marshall, J., and Plumb, R. A., 2008: Atmosphere, Ocean, and Climate Dynamics: An Introductory Text, Academic Press. · Vallis, G. K
Oceanography and Atmospheric Sciences
Kurapov, Alexander
Oceanography and Atmospheric Sciences 19592009 WayneBurt. #12;Oceanography and Atmospheric in Oceanography (TENOC). Wayne Burt immediately responds with proposal to President Strand of Oregon State College to start a graduate Department of Oceanography. 1959 Oregon State Board of Higher Education approves
Atmospheric Thermodynamics Composition
Russell, Lynn
1 Atmospheric Thermodynamics Ch1 Composition Ch2 Laws Ch3 Transfers Ch12 EnergyBalance Ch4 Water Ch Sciences: Atmospheric Thermodynamics Instructor: Lynn Russell, NH343 http #12;2 Review from Ch. 1 · Thermodynamic quantities · Composition · Pressure · Density · Temperature
Comment on ``Discrete Boltzmann Equation for Microfluidics''
Luo, Li-Shi
Comment on ``Discrete Boltzmann Equation for Microfluidics'' In a recent Letter [1], Li and Kwok use a lattice Boltzmann equation (LBE) for microfluidics. Their main claim is that an LBE model for microfluidics can be constructed based on the ``Bhatnagar-Gross-Kooky [sic]'' model by including ``the
On the discrete bicycle transformation S. Tabachnikov
Tabachnikov, Sergei
On the discrete bicycle transformation S. Tabachnikov E. Tsukerman 1 Introduction The motivation for this paper comes from the study of a simple model of bicycle motion. The bicycle is modeled as an oriented segment in the plane of fixed length , the wheelbase of the bicycle. The motion is constrained so
Model Uncertainty in Discrete Event Stanley Young
Garg, Vijay
Abstract Earlier work concerning control of discrete event systems usually assumed that a correct model to test for the correct model or noti cation that the remaining models cannot be controllably distin- guished. We use the nite state machine model with controllable and uncontrollable events presented
Contributions to the development of residual discretizations
Paris-Sud XI, Université de
Contributions to the development of residual discretizations for hyperbolic conservation laws with application to shallow water flows Manuscript submitted in fulfillment of the requirements for the obtention;Contents 1 Overview 9 1.1 Residual schemes for hyperbolic conservation laws
Dynamic Discrete Power Control in Cellular Networks
Avrachenkov, Konstantin
1 Dynamic Discrete Power Control in Cellular Networks Eitan Altman, Konstantin Avrachenkov, Ishai. In each of the two frameworks, we consider both cooperative as well as non-cooperative power control. We utilization. It is, therefore, in the interests of the users to control their transmit powers levels so
Regularized Discrete Optimal Transport Sira Ferradans1
Boyer, Edmond
. Jean-Francois.Aujol@math.u-bordeaux1.fr Abstract. This article introduces a generalization of discrete in modified images. In this article, we propose a variational formalism to relax and regularize the transport dedicated linear solvers (transportation simplex) and combinatorial algorithms (such as the Hungarian
Chow's Team Petri Net Models discrete event
Kaber, David B.
", and "high" plate contents CELISCA: collection of physiology data based on NCSU prototype Output1 CELISCA: collection of physiology data based on New NCSU prototype Output2 #12;k Chow's Team Petri Net Models discrete event stochastic models (set fixed time interval updates
Discrete profile alignment via constrained information bottleneck
Chechik, Gal
Discrete profile alignment via constrained information bottleneck Sean O'Rourke seano@cs.ucsd.edu Abstract Amino acid profiles, which capture position-specific mutation prob- abilities, are a richer encoding of biological sequences than the in- dividual sequences themselves. However, profile comparisons
Discrete profile alignment via constrained information bottleneck
Chechik, Gal
Discrete profile alignment via constrained information bottleneck Sean O'Rourke # seano@cs.ucsd.edu Abstract Amino acid profiles, which capture positionÂspecific mutation probÂ abilities, are a richer encoding of biological sequences than the inÂ dividual sequences themselves. However, profile comparisons
Discretization and Algorithms for Strong Coupling in Computational Aeroelasticity
8 4.1 Flow discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2 Structural discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3 Mimicing the energy.4 A bifurcation at M1 = 0:95 . . . . . . . . . . . . . . . . . . . . . . . . . . 22 6.5 Stability chart
Controller Synthesis of Discrete Linear Plants Using MATTEO SLANINA
Sankaranarayanan, Sriram
Controller Synthesis of Discrete Linear Plants Using Polyhedra MATTEO SLANINA Stanford University controllers for linear discrete systems with disturbances. Given a plant description and a safety We study techniques for synthesizing synchronous controllers for affine plants with disturbances
Defining Employee Perceptions of Discretion: When, Where, and How
Thompson, Rebecca Jean
2013-12-10T23:59:59.000Z
discretion: choice over when, where, and how one works. Second, the influence of these three forms of discretion on both work-related outcomes (job satisfaction, burnout, and turnover intentions) and nonwork-related outcomes (life satisfaction, work...
Hiroshi Miki; Hiroaki Goda; Satoshi Tsujimoto
2012-02-29T23:59:59.000Z
Discrete spectral transformations of skew orthogonal polynomials are presented. From these spectral transformations, it is shown that the corresponding discrete integrable systems are derived both in 1+1 dimension and in 2+1 dimension. Especially in the (2+1)-dimensional case, the corresponding system can be extended to 2x2 matrix form. The factorization theorem of the Christoffel kernel for skew orthogonal polynomials in random matrix theory is presented as a by-product of these transformations.
Miki, Hiroshi; Tsujimoto, Satoshi
2011-01-01T23:59:59.000Z
Discrete spectral transformations of skew orthognal polynomials are presented. From these spectral transformations, it is shown that the corresponding discrete integrable systems are derived both in 1+1 dimension and in 2+1 dimension. Especially in the 2+1 dimensional case, the corresponding system can be extended to 2x2 matrix form. The factorization theorem of the skew-Christoffel kernel in random matrix theory is presented as a by-product of these transformations.
Toxicity of atmospheric aerosols on marine phytoplankton
2009-01-01T23:59:59.000Z
address: Center for Atmospheric Chemistry Study, Departmenttween phytoplankton, atmospheric chemistry, and climate areno. 12 ? 4601– 4605 CHEMISTRY Atmospheric aerosol deposition
ERROR ESTIMATES FOR THE EULER DISCRETIZATION OF AN ...
2014-12-10T23:59:59.000Z
Optimal control, nonlinear systems, state constraints, Euler discretization, rate of ... convergence, provided with modern variational techniques, are also [25]; ...
Extinction dynamics of a discrete population in an oasis
Berti, Stefano; Vergni, Davide; Vulpiani, Angelo
2015-01-01T23:59:59.000Z
Understanding the conditions ensuring the persistence of a population is an issue of primary importance in population biology. The first theoretical approach to the problem dates back to the 50's with the KiSS (after Kierstead, Slobodkin and Skellam) model, namely a continuous reaction-diffusion equation for a population growing on a patch of finite size $L$ surrounded by a deadly environment with infinite mortality -- i.e. an oasis in a desert. The main outcome of the model is that only patches above a critical size allow for population persistence. Here, we introduce an individual-based analogue of the KiSS model to investigate the effects of discreteness and demographic stochasticity. In particular, we study the average time to extinction both above and below the critical patch size of the continuous model and investigate the quasi-stationary distribution of the number of individuals for patch sizes above the critical threshold.
Discrete mechanics, optimal control and formation flying spacecraft
Patrick, George
Discrete mechanics, optimal control and formation flying spacecraft Oliver Junge Center-BlÂ¨obaum partially supported by the CRC 376 Oliver Junge Discrete mechanics, optimal control and formation flying spacecraft p.1 #12;Outline mechanical optimal control problem direct discretization of the variational
Modelling and numerical approximation of a 2.5D set of equations for mesoscale atmospheric processes
Kalise, Dante
2011-01-01T23:59:59.000Z
The set of 3D inviscid primitive equations for the atmosphere is dimensionally reduced by a Discontinuous Galerkin discretization in one horizontal direction. The resulting model is a 2D system of balance laws where with a source term depending on the layering procedure and the choice of coupling fluxes, which is established in terms of upwind considerations. The "2.5D" system is discretized via a WENO-TVD scheme based in a flux limiter centered approach. We study four tests cases related to atmospheric phenomena to analyze the physical validity of the model.
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2004-07-08T23:59:59.000Z
This Notice ensures that DOE uniformly meets the requirements of the Homeland Security Advisory System outlined in Homeland Security Presidential Directive-3, Threat Conditions and Associated Protective Measures, dated 3-11-02, and provides responses specified in Presidential Decision Directive 39, U.S. Policy on Counterterrorism (U), dated 6-21-95. It cancels DOE N 473.8, Security Conditions, dated 8-7-02. Extended until 7-7-06 by DOE N 251.64, dated 7-7-05 Cancels DOE N 473.8
AVERAGES ALONG POLYNOMIAL SEQUENCES IN DISCRETE NILPOTENT GROUPS: SINGULAR RADON TRANSFORMS
Magyar, Akos
AVERAGES ALONG POLYNOMIAL SEQUENCES IN DISCRETE NILPOTENT GROUPS: SINGULAR RADON TRANSFORMS can consider discrete maximal Radon transforms, which have applications to pointwise ergodic theo- rems, and discrete singular Radon transforms. In this paper we prove L2 boundedness of discrete
Degeneracy and Discreteness in Cosmological Model Fitting
Teng, Huan-Yu; Hu, Huan-Chen; Zhang, Tong-Jie
2015-01-01T23:59:59.000Z
We explore the degeneracy and discreteness problems in the standard cosmological model ({\\Lambda}CDM). We use the Observational Hubble Data (OHD) and the type Ia supernova (SNe Ia) data to study this issue. In order to describe the discreteness in fitting of data, we define a factor G to test the influence from each single data point and analyze the goodness of G. Our results indicate that a higher absolute value of G shows a better capability of distinguishing models, which means the parameters are restricted into smaller confidence intervals with a larger figure of merit evaluation. Consequently, we claim that the factor G is an effective way in model differentiation when using different models to fit the observational data.
Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster)
Clifton, A.
2012-12-01T23:59:59.000Z
Multi-megawatt, utility-scale wind turbines operate in turbulent and dynamic winds that impact turbine performance in ways that are gradually becoming better understood. This poster presents a study made using a turbulent flow field simulator (TurbSim) and a Turbine aeroelastic simulator (FAST) of the response of a generic 1.5 MW wind turbine to changing inflow. The turbine power output is found to be most sensitive to wind speed and turbulence intensity, but the relationship depends on the wind speed with respect to the turbine's rated wind speed. Shear is found to be poorly correlated to power. A machine learning method called 'regression trees' is used to create a simple model of turbine performance that could be used as part of the wind resource assessment process. This study has used simple flow fields and should be extended to more complex flows, and validated with field observations.
Condition assessment of nonlinear processes
Hively, Lee M. (Philadelphia, TN); Gailey, Paul C. (Athens, OH); Protopopescu, Vladimir A. (Knoxville, TN)
2002-01-01T23:59:59.000Z
There is presented a reliable technique for measuring condition change in nonlinear data such as brain waves. The nonlinear data is filtered and discretized into windowed data sets. The system dynamics within each data set is represented by a sequence of connected phase-space points, and for each data set a distribution function is derived. New metrics are introduced that evaluate the distance between distribution functions. The metrics are properly renormalized to provide robust and sensitive relative measures of condition change. As an example, these measures can be used on EEG data, to provide timely discrimination between normal, preseizure, seizure, and post-seizure states in epileptic patients. Apparatus utilizing hardware or software to perform the method and provide an indicative output is also disclosed.
13, 1479714822, 2013 Atmospheric waves
Lovejoy, Shaun
.5194/acpd-13-14797-2013 © Author(s) 2013. CC Attribution 3.0 License. Sciences ss Atmospheric Chemistry and Physics OpenAccess Atmospheric Chemistry and Physics OpenAccess Discussions Atmospheric Measurement s Discussions This discussion paper is/has been under review for the journal Atmospheric Chemistry and Physics
Observations of Exoplanet Atmospheres
Crossfield, Ian J M
2015-01-01T23:59:59.000Z
Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics & circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly-imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.
Doctoral Programs Atmospheric, Oceanic & Space Sciences
Eustice, Ryan
Research Areas Atmosphere Biosphere Interactions Atmospheric Chemistry, Aerosols & Air QualityDoctoral Programs Atmospheric, Oceanic & Space Sciences Geoscience & Remote Sensing Space & Planetary Physics 01/14 Ver.3.1 Atmospheric,OceanicandSpaceSciences Atmospheric, Oceanic & Space Sciences
Application of Genetic Algorithm to Optimal Design of Central Air-Conditioning Water System
Feng, X.; Zou, Y.; Long, W.
2006-01-01T23:59:59.000Z
The optimal design of air-conditioning water system is an optimization problem of functions that depend on a series of nonlinear discrete multi-variables.Many traditional methods are not satisfactory when applied in this field. However, genetic...
Novel coupling scheme to control dynamics of coupled discrete systems
Snehal M. Shekatkar; G. Ambika
2014-11-05T23:59:59.000Z
We present a new coupling scheme to control spatio-temporal patterns and chimeras on 1-d and 2-d lattices and random networks of discrete dynamical systems. The scheme involves coupling with an external lattice or network of damped systems. When the system network and external network are set in a feedback loop, the system network can be controlled to a homogeneous steady state or synchronized periodic state with suppression of the chaotic dynamics of the individual units. The control scheme has the advantage that its design does not require any prior information about the system dynamics or its parameters and works effectively for a range of parameters of the control network. We analyze the stability of the controlled steady state or amplitude death state of lattices using the theory of circulant matrices and Routh-Hurwitz's criterion for discrete systems and this helps to isolate regions of effective control in the relevant parameter planes. The conditions thus obtained are found to agree well with those obtained from direct numerical simulations in the specific context of lattices with logistic map and Henon map as on-site system dynamics. We show how chimera states developed in an experimentally realizable 2-d lattice can be controlled using this scheme. We propose this mechanism can provide a phenomenological model for the control of spatio-temporal patterns in coupled neurons due to non-synaptic coupling with the extra cellular medium. We extend the control scheme to regulate dynamics on random networks and adapt the master stability function method to analyze the stability of the controlled state for various topologies and coupling strengths.
Novel coupling scheme to control dynamics of coupled discrete systems
Snehal M. Shekatkar; G. Ambika
2015-08-08T23:59:59.000Z
We present a new coupling scheme to control spatio-temporal patterns and chimeras on 1-d and 2-d lattices and random networks of discrete dynamical systems. The scheme involves coupling with an external lattice or network of damped systems. When the system network and external network are set in a feedback loop, the system network can be controlled to a homogeneous steady state or synchronized periodic state with suppression of the chaotic dynamics of the individual units. The control scheme has the advantage that its design does not require any prior information about the system dynamics or its parameters and works effectively for a range of parameters of the control network. We analyze the stability of the controlled steady state or amplitude death state of lattices using the theory of circulant matrices and Routh-Hurwitz's criterion for discrete systems and this helps to isolate regions of effective control in the relevant parameter planes. The conditions thus obtained are found to agree well with those obtained from direct numerical simulations in the specific context of lattices with logistic map and Henon map as on-site system dynamics. We show how chimera states developed in an experimentally realizable 2-d lattice can be controlled using this scheme. We propose this mechanism can provide a phenomenological model for the control of spatio-temporal patterns in coupled neurons due to non-synaptic coupling with the extra cellular medium. We extend the control scheme to regulate dynamics on random networks and adapt the master stability function method to analyze the stability of the controlled state for various topologies and coupling strengths.
Sevostianov, Igor
and recommended properties of the plasti®cator are derived under the condition that material should possessOverall properties of composites with physically non-linear discrete phase I. Sevostianov a,*, V elastic matrix and visco-plastic inclusions. Dense hydroxyapatite is considered as the matrix material
Fancher, Robert H.
1997-01-01T23:59:59.000Z
This study used discrete event simulation to model the personnel recruiting process for a U.S. Army recruiting company. Actual data from the company was collected and used to build the simulation model. The model is run under various conditions...
Compartmentalization analysis using discrete fracture network models
La Pointe, P.R.; Eiben, T.; Dershowitz, W. [Golder Associates, Redmond, VA (United States); Wadleigh, E. [Marathon Oil Co., Midland, TX (United States)
1997-08-01T23:59:59.000Z
This paper illustrates how Discrete Fracture Network (DFN) technology can serve as a basis for the calculation of reservoir engineering parameters for the development of fractured reservoirs. It describes the development of quantitative techniques for defining the geometry and volume of structurally controlled compartments. These techniques are based on a combination of stochastic geometry, computational geometry, and graph the theory. The parameters addressed are compartment size, matrix block size and tributary drainage volume. The concept of DFN models is explained and methodologies to compute these parameters are demonstrated.
Bilinear control of discrete spectrum Schrödinger operators
Kais Ammari; Zied Ammari
2010-05-17T23:59:59.000Z
The bilinear control problem of the Schr\\"odinger equation $i\\frac{\\partial}{\\partial t}\\psi(t)$ $=(A+u(t) B)\\psi(t)$, where $u(t)$ is the control function, is investigated through topological irreducibility of the set $\\mathfrak{M}=\\{e^{-it (A+u B)}, u\\in \\mathbb{R}, t>0\\}$ of bounded operators. This allows to prove the approximate controllability of such systems when the uncontrolled Hamiltonian $A$ has a simple discrete spectrum and under an appropriate assumption on $B$.
Quantumness of discrete Hamiltonian cellular automata
Hans-Thomas Elze
2014-07-08T23:59:59.000Z
We summarize a recent study of discrete (integer-valued) Hamiltonian cellular automata (CA) showing that their dynamics can only be consistently defined, if it is linear in the same sense as unitary evolution described by the Schr\\"odinger equation. This allows to construct an invertible map between such CA and continuous quantum mechanical models, which incorporate a fundamental scale. Presently, we emphasize general aspects of these findings, the construction of admissible CA observables, and the existence of solutions of the modified dispersion relation for stationary states.
SNAP:SN (Discrete Ordinates) Application Proxy
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million CubicRefiners SwitchBenefits Â»DepartmentWastewaterSLIDESHOW:2003 SN CRACSNAP:SN (Discrete
Laboratory for Atmospheric and
Mojzsis, Stephen J.
. Along with this growth came a new building on campus and a new name: the Laboratory for Atmospheric of the Sun to the outermost fringes of the solar system. With LASP's continuing operations role in the planet traditional and stable approach based on federal agency funding of research grant
Laboratory for Atmospheric and
Mojzsis, Stephen J.
Laboratory for Atmospheric and Space Physics Activity Report 2013 University of Colorado at Boulder from the Naval Research Center and the Air Force Cambridge Research Laboratory (now the Phillips Laboratory), the University of Colorado formed a research group called the Upper Air Laboratory (UAL
Laboratory for Atmospheric and
Mojzsis, Stephen J.
Laboratory for Atmospheric and Space Physics Activity Report 2008 University of Colorado at Boulder, Jet Propulsion Laboratory) LASP: A Brief History In 1946-47, a handful of American universities joined Laboratory (now the Phillips Laboratory), the University of Colorado formed a research group called the Upper
Laboratory for Atmospheric and
Mojzsis, Stephen J.
1 Laboratory for Atmospheric and Space Physics Activity Report 2010 University of Colorado from the Na- val Research Center and the Air Force Cambridge Research Laboratory (now the Phillips Laboratory), the University of Colorado formed a research group called the Upper Air Laboratory (UAL
Discrete Event Simulation of Molecular Dynamics with Configurable Logic
Herbordt, Martin
: {jtmodel|herbordt}@bu.edu Abstract: Molecular dynamics simulation based on discrete event simulation (DMD. Herbordt Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 EMail
Lowest-rank Solutions of Continuous and Discrete Lyapunov ...
2012-10-08T23:59:59.000Z
Lyapunov equations are of great importance but generally diffi- cult to achieve in ... of the discrete Lyapunov inequality can be efficiently solved by a linear ...
Lowest-rank Solutions of Continuous and Discrete Lyapunov ...
Ziyan Luo
2012-10-09T23:59:59.000Z
Oct 9, 2012 ... Abstract: The low-rank solutions of continuous and discrete Lyapunov equations are of great importance but generally difficult to achieve in ...
Discretization schemes for diffusion operators on general meshes
Herbin, Raphaèle
: Navier Stokes equations Flow in porous media, Darcy equation. discretization of -div( u)) A can Supplementary constraint from the oil reservoir simulation community: cell centred schemes transport equations
Properties of Ellipticity Correlation with Atmospheric Structure From Gemini South
Asztalos, Stephen J.; /LLNL, Livermore; de Vries, W.H.; /UC, Davis /LLNL, Livermore; Rosenberg, L.J; Treadway, T.; /LLNL, Livermore; Burke, D.; /SLAC; Claver, C.; Saha, A.; /NOAO, Tucson; Puxley, P.; /Gemini Observ., La Serena
2007-01-17T23:59:59.000Z
Cosmic shear holds great promise for a precision independent measurement of {Omega}{sub m}, the mass density of the universe relative to the critical density. The signal is expected to be weak, so a thorough understanding of systematic effects is crucial. An important systematic effect is the atmosphere: shear power introduced by the atmosphere is larger than the expected signal. Algorithms exist to extract the cosmic shear from the atmospheric component, though a measure of their success applied to a range of seeing conditions is lacking. To gain insight into atmospheric shear, Gemini South imaging in conjunction with ground condition and satellite wind data were obtained. We find that under good seeing conditions Point-Spread-Function (PSF) correlations persist well beyond the separation typical of high-latitude stars. Under these conditions, ellipticity residuals based on a simple PSF interpolation can be reduced to within a factor of a few of the shot-noise induced ellipticity floor. We also find that the ellipticity residuals are highly correlated with wind direction. Finally, we correct stellar shapes using a more sophisticated procedure and generate shear statistics from stars. Under all seeing conditions in our data set the residual correlations lie everywhere below the target signal level. For good seeing we find that the systematic error attributable to atmospheric turbulence is comparable in magnitude to the statistical error (shape noise) over angular scales relevant to present lensing surveys.
Differential atmospheric tritium sampler
Griesbach, O.A.; Stencel, J.R.
1987-10-02T23:59:59.000Z
An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The moisture then passes through a combustion chamber where hydrogen gas in the form of H/sub 2/ or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.
Lifetimes and eigenstates in atmospheric chemistry
Prather, Michael J
1994-01-01T23:59:59.000Z
Perturbation dynamics in atmospheric chemistry. J. Geophys.isotopic variations in atmospheric chemistry. Geophys. Res.M. et al. 2001 Atmospheric chemistry and greenhouse gases (
Atmospheric chemistry of an Antarctic volcanic plume
2010-01-01T23:59:59.000Z
L. , et al. (2010), Atmospheric chemistry results from theI. , et al. (2006), Atmospheric chemistry of a 33 – 34 hourvolcanic eruptions on atmospheric chemistry, Chem. Geol. ,
Kansa, E., E-mail: edwardjkansa@netzero.com [Computational Sciences, LLC, 8000 Madison Blvd., Madison, AL 35758-2035 (United States); Shumlak, U., E-mail: shumlak@uw.edu [Computational Sciences, LLC, 8000 Madison Blvd., Madison, AL 35758-2035 (United States); Aerospace and Energetics Research Program, University of Washington, Box 352250, Seattle, WA 98195 (United States); Tsynkov, S., E-mail: tsynkov@math.ncsu.edu [Computational Sciences, LLC, 8000 Madison Blvd., Madison, AL 35758-2035 (United States); Department of Mathematics, North Carolina State University, Box 8205, Raleigh, NC 27695 (United States)
2013-02-01T23:59:59.000Z
Confining dense plasma in a field reversed configuration (FRC) is considered a promising approach to fusion. Numerical simulation of this process requires setting artificial boundary conditions (ABCs) for the magnetic field because whereas the plasma itself occupies a bounded region (within the FRC coils), the field extends from this region all the way to infinity. If the plasma is modeled using single fluid magnetohydrodynamics (MHD), then the exterior magnetic field can be considered quasi-static. This field has a scalar potential governed by the Laplace equation. The quasi-static ABC for the magnetic field is obtained using the method of difference potentials, in the form of a discrete Calderon boundary equation with projection on the artificial boundary shaped as a parallelepiped. The Calderon projection itself is computed by convolution with the discrete fundamental solution on the three-dimensional Cartesian grid.
Twisted X-rays: incoming waveforms yielding discrete diffraction patterns for helical structures
Friesecke, Gero; Jüstel, Dominik
2015-01-01T23:59:59.000Z
Conventional X-ray methods use incoming plane waves and result in discrete diffraction patterns when scattered at crystals. Here we find, by a systematic method, incoming waveforms which exhibit discrete diffraction patterns when scattered at helical structures. As examples we present simulated diffraction patterns of carbon nanotubes and tobacco mosaic virus. The new incoming waveforms, which we call twisted waves due to their geometric shape, are found theoretically as closed-form solutions to Maxwell's equations. The theory of the ensuing diffraction patterns is developed in detail. A twisted analogue of the Von Laue condition is seen to hold, with the peak locations encoding the symmetry and the helix parameters, and the peak intensities indicating the electronic structure in the unit cell. If suitable twisted X-ray sources can in the future be realized experimentally, it appears from our mathematical results that they will provide a powerful tool for directly determining the detailed atomic structure of ...
Bayerschen, E; Wulfinghoff, S; Weygand, D; Böhlke, T
2015-01-01T23:59:59.000Z
The gradient crystal plasticity framework of Wulfinghoff et al. [53] incorporating an equivalent plastic strain and grain boundary yielding, is extended with additional grain boundary hardening. By comparison to averaged results from many discrete dislocation dynamics (DDD) simulations of an aluminum type tricrystal under tensile loading, the new hardening parameter in the continuum model is calibrated. It is shown that although the grain boundaries (GBs) in the discrete simulations are impenetrable, an infinite GB yield strength corresponding to microhard GB conditions, is not applicable in the continuum model. A combination of a finite GB yield strength with an isotropic bulk Voce hardening relation alone also fails to model the plastic strain profiles obtained by DDD. Instead, a finite GB yield strength in combination with GB hardening depending on the equivalent plastic strain at the GBs is shown to give a better agreement to DDD results. The differences in the plastic strain profiles obtained in DDD simu...
Information storage capacity of discrete spin systems
Beni Yoshida
2012-12-24T23:59:59.000Z
Understanding the limits imposed on information storage capacity of physical systems is a problem of fundamental and practical importance which bridges physics and information science. There is a well-known upper bound on the amount of information that can be stored reliably in a given volume of discrete spin systems which are supported by gapped local Hamiltonians. However, all the previously known systems were far below this theoretical bound, and it remained open whether there exists a gapped spin system that saturates this bound. Here, we present a construction of spin systems which saturate this theoretical limit asymptotically by borrowing an idea from fractal properties arising in the Sierpinski triangle. Our construction provides not only the best classical error-correcting code which is physically realizable as the energy ground space of gapped frustration-free Hamiltonians, but also a new research avenue for correlated spin phases with fractal spin configurations.
Discrete solitons and vortices on anisotropic lattices
Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515 (United States); Frantzeskakis, D.J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece); Carretero-Gonzalez, R. [Nonlinear Dynamical Systems Group, Department of Mathematics and Statistics, and Computational Science Research Center, San Diego State University, San Diego, California 92182-7720 (United States); Malomed, B.A. [Department of Interdisciplinary Studies, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Bishop, A.R. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2005-10-01T23:59:59.000Z
We consider the effects of anisotropy on solitons of various types in two-dimensional nonlinear lattices, using the discrete nonlinear Schroedinger equation as a paradigm model. For fundamental solitons, we develop a variational approximation that predicts that broad quasicontinuum solitons are unstable, while their strongly anisotropic counterparts are stable. By means of numerical methods, it is found that, in the general case, the fundamental solitons and simplest on-site-centered vortex solitons ('vortex crosses') feature enhanced or reduced stability areas, depending on the strength of the anisotropy. More surprising is the effect of anisotropy on the so-called 'super-symmetric' intersite-centered vortices ('vortex squares'), with the topological charge S equal to the square's size M: we predict in an analytical form by means of the Lyapunov-Schmidt theory, and confirm by numerical results, that arbitrarily weak anisotropy results in dramatic changes in the stability and dynamics in comparison with the degenerate, in this case, isotropic, limit.
University of Michigan and NBER "Identification of Discrete Choice
Presenter: Jeremy Fox University of Michigan and NBER "Identification of Discrete Choice Models;Identification of Discrete Choice Models for Bundles and Binary Games Jeremy T. Fox University of Michigan and NBER Natalia Lazzati University of Michigan March 2014 Abstract We study nonparametric identification
Model Transformation with Hierarchical Discrete-Event Control
Model Transformation with Hierarchical Discrete- Event Control Thomas Huining Feng Electrical permission. #12;Model Transformation with Hierarchical Discrete-Event Control by Huining Feng B.S. (Nanjing Date Date University of California, Berkeley Spring 2009 #12;Model Transformation with Hierarchical
Directed Control of Discrete Event Systems: Optimization Based Approach
Kumar, Ratnesh
Directed Control of Discrete Event Systems: Optimization Based Approach J. Huang and R. Kumar an optimal director. Keywords: Discrete event systems, optimal control, supervisory control, directed control sense for plants that are executor of controllable events. In this paper we develop an optimization
EQUILIBRIUM RECONSTRUCTION FROM DISCRETE MAGNETIC MEASUREMENTS IN A TOKAMAK
Faugeras, Blaise
EQUILIBRIUM RECONSTRUCTION FROM DISCRETE MAGNETIC MEASUREMENTS IN A TOKAMAK Blaise Faugeras (joint of the equilibrium in a Tokamak from discrete magnetic mea- surements. In order to solve this inverse problem we of a plasma in a Tokamak [1]. The state variable of interest in the modelization of such an equilibrium under
Institute of Operations Research Discrete Optimization and Logistics
Al Hanbali, Ahmad
Institute of Operations Research Discrete Optimization and Logistics 1 Prof. Dr. Stefan Nickel Health Care Logistics: Overview Health Care Logistics 11/28/2013 #12;Institute of Operations Research Discrete Optimization and Logistics 2 Prof. Dr. Stefan Nickel Health Care Logistics: Overview Health Care
ISS-Lyapunov Functions for Discontinuous Discrete-Time Systems
Paris-Sud XI, Université de
1 ISS-Lyapunov Functions for Discontinuous Discrete-Time Systems Lars Gr¨une and Christopher M. Kellett Abstract Input-to-State Stability (ISS) and the ISS-Lyapunov function have proved to be useful- ous discrete-time dynamics, we investigate ISS-Lyapunov functions for such systems. ISS-Lyapunov
From Discrete Specifications to Hybrid Control1 Paulo Tabuada
Pappas, George J.
@seas.upenn.edu Abstract A great challenge for modern systems theory is the de- sign of controllers for continuous systems inside physical devices has resulted in great challenges for modern and future systems and control theory given a discrete- time controllable linear system and a discrete specifica- tion (in the form
Discrete Wavelet Diffusion for Image Denoising Kashif Rajpoot1
Rajpoot, Nasir
Discrete Wavelet Diffusion for Image Denoising Kashif Rajpoot1 , Nasir Rajpoot2 , J. Alison Noble1 to iterative wavelet shrinkage, but only for (1) MallatZhong dyadic wavelet transform and (2) Haar wavelet shrinkage in the standard discrete wavelet transform (DWT) domain. Two of the major advantages
A DISCRETE WAVELET ANALYSIS OF FREAK WAVES IN THE OCEAN
A DISCRETE WAVELET ANALYSIS OF FREAK WAVES IN THE OCEAN EN-BING LIN AND PAUL C. LIU Received 25 wavelet analysis on a freak wave. We demonstrate several applications of wavelets and discrete and continuous wavelet transforms on the study of a freak wave. A modeling setting for freak waves will also
GRADIENT THEORY FOR PLASTICITY VIA HOMOGENIZATION OF DISCRETE DISLOCATIONS
Garroni, Adriana
GRADIENT THEORY FOR PLASTICITY VIA HOMOGENIZATION OF DISCRETE DISLOCATIONS ADRIANA GARRONI theory for plasticity from a model of discrete dislocations. We restrict our analysis to the case of a cylindrical symmetry for the crystal in exam, so that the mathematical formulation will involve a two
MS Thesis Defense A Combined Discrete-dislocation/Scale-
Grujicic, Mica
MS Thesis Defense A Combined Discrete-dislocation/Scale- dependent Crystal Plasticity Analysis of Deformation and Fracture in Nanomaterials A Combined Discrete-dislocation/Scale- dependent Crystal Plasticity der Giessen, Needleman 1995) Crystal Plasticity Model Results and ComparisonII. Micro-beam Bending
Mechanical Integrators Derived from a Discrete Variational Principle
Marsden, Jerrold
Mechanical Integrators Derived from a Discrete Variational Principle Jerey M. Wendlandt1;2 Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720, USA Jerrold E. Marsden3 for mechanical system simulation are created by using discrete algorithms to approximate the continuous equations
A Discrete-Event Systems Approach to Modeling Dextrous Manipulation
Graham, Nick
A Discrete-Event Systems Approach to Modeling Dextrous Manipulation S. L. Ricker? N. Sarkar?y K-event systems. The applicability of discrete-event systems to the modeling of dextrous manipulation tasks of the manipulation task, resulting in control discontinuities. The need for tech- niques to facilitate a smooth
Discrete Applied Mathematics 85 (1998) 59-70 MATHEMATICS
Fomin, Fedor V.
1998-01-01T23:59:59.000Z
ELSEYIER DISCRETE APPLIED Discrete Applied Mathematics 85 (1998) 59-70 MATHEMATICS Helicopter problem on a graph in which one cop in a helicopter flying from vertex to vertex tries to catch the robber. In each of the following steps, Cop moves (flies by helicopter) to some vertex (not necessarily adjacent
Nash Equilibria in Discrete Routing Games with Convex Latency Functions
Mavronicolas, Marios
Nash Equilibria in Discrete Routing Games with Convex Latency Functions Martin Gairing1 , Thomas L 20537, Nicosia CY-1678, Cyprus. mavronic@ucy.ac.cy Abstract. We study Nash equilibria in a discrete, this is the first time that mixed Nash equilibria for routing games have been studied in combination with non
A Model of Intra-seasonal Oscillations in the Earth atmosphere
Elena Kartashova; Victor S. L'vov
2007-04-04T23:59:59.000Z
We suggest a way of rationalizing an intra-seasonal oscillations (IOs) of the Earth atmospheric flow as four meteorological relevant triads of interacting planetary waves, isolated from the system of all the rest planetary waves. Our model is independent of the topography (mountains, etc.) and gives a natural explanation of IOs both in the North and South Hemispheres. Spherical planetary waves are an example of a wave mesoscopic system obeying discrete resonances that also appears in other areas of physics.
Constant pressure and temperature discrete-time Langevin molecular dynamics
Niels Grønbech-Jensen; Oded Farago
2014-11-13T23:59:59.000Z
We present a new and improved method for simultaneous control of temperature and pressure in molecular dynamics simulations with periodic boundary conditions. The thermostat-barostat equations are build on our previously developed stochastic thermostat, which has been shown to provide correct statistical configurational sampling for any time step that yields stable trajectories. Here, we extend the method and develop a set of discrete-time equations of motion for both particle dynamics and system volume in order to seek pressure control that is insensitive to the choice of the numerical time step. The resulting method is simple, practical, and efficient. The method is demonstrated through direct numerical simulations of two characteristic model systems - a one dimensional particle chain for which exact statistical results can be obtained and used as benchmarks, and a three dimensional system of Lennard-Jones interacting particles simulated in both solid and liquid phases. The results, which are compared against the method of Kolb & Dunweg, show that the new method behaves according to the objective, namely that acquired statistical averages and fluctuations of configurational measures are accurate and robust against the chosen time step applied to the simulation.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) | SciTech Connect Journal Article:Technologies | BlandineDecember 2012U.S.DataStudy (CHAPS)ArchiveListAtmospheric Heat
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) | SciTech Connect Journal Article:Technologies | BlandineDecember 2012U.S.DataStudy (CHAPS)ArchiveListAtmospheric
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,Separation 23Tribal EnergyCatalyticPreparation and properties of hollowusingAnalytical considerations inAtmospheric
Office of Scientific and Technical Information (OSTI)
For further opti- misation of psfent, we could also use a narrower range of weather conditions and carry out the same process multiple times to derive priors as a...
Discrete Scale Relativity And SX Phoenicis Variable Stars
R. L. Oldershaw
2009-06-18T23:59:59.000Z
Discrete Scale Relativity proposes a new symmetry principle called discrete cosmological self-similarity which relates each class of systems and phenomena on a given Scale of nature's discrete cosmological hierarchy to the equivalent class of analogue systems and phenomena on any other Scale. The new symmetry principle can be understood in terms of discrete scale invariance involving the spatial, temporal and dynamic parameters of all systems and phenomena. This new paradigm predicts a rigorous discrete self-similarity between Stellar Scale variable stars and Atomic Scale excited atoms undergoing energy-level transitions and sub-threshold oscillations. Previously, methods for demonstrating and testing the proposed symmetry principle have been applied to RR Lyrae, Delta Scuti and ZZ Ceti variable stars. In the present paper we apply the same analytical methods and diagnostic tests to a new class of variable stars: SX Phoenicis variables. Double-mode pulsators are shown to provide an especially useful means of testing the uniqueness and rigor of the conceptual principles and discrete self-similar scaling of Discrete Scale Relativity.
An efficient permeability scaling-up technique applied to the discretized flow equations
Urgelli, D.; Ding, Yu [Institut Francais du Petrole, Rueil Malmaison (France)
1997-08-01T23:59:59.000Z
Grid-block permeability scaling-up for numerical reservoir simulations has been discussed for a long time in the literature. It is now recognized that a full permeability tensor is needed to get an accurate reservoir description at large scale. However, two major difficulties are encountered: (1) grid-block permeability cannot be properly defined because it depends on boundary conditions; (2) discretization of flow equations with a full permeability tensor is not straightforward and little work has been done on this subject. In this paper, we propose a new method, which allows us to get around both difficulties. As the two major problems are closely related, a global approach will preserve the accuracy. So, in the proposed method, the permeability up-scaling technique is integrated in the discretized numerical scheme for flow simulation. The permeability is scaled-up via the transmissibility term, in accordance with the fluid flow calculation in the numerical scheme. A finite-volume scheme is particularly studied, and the transmissibility scaling-up technique for this scheme is presented. Some numerical examples are tested for flow simulation. This new method is compared with some published numerical schemes for full permeability tensor discretization where the full permeability tensor is scaled-up through various techniques. Comparing the results with fine grid simulations shows that the new method is more accurate and more efficient.
Generalized discrete orbit function transforms of affine Weyl groups
Tomasz Czy?ycki; Ji?í Hrivnák
2014-11-14T23:59:59.000Z
The affine Weyl groups with their corresponding four types of orbit functions are considered. Two independent admissible shifts, which preserve the symmetries of the weight and the dual weight lattices, are classified. Finite subsets of the shifted weight and the shifted dual weight lattices, which serve as a sampling grid and a set of labels of the orbit functions, respectively, are introduced. The complete sets of discretely orthogonal orbit functions over the sampling grids are found and the corresponding discrete Fourier transforms are formulated. The eight standard one-dimensional discrete cosine and sine transforms form special cases of the presented transforms.
An Excursion-Theoretic Approach to Stability of Discrete-Time Stochastic Hybrid Systems
Chatterjee, Debasish, E-mail: chatterjee@control.ee.ethz.ch [ETH Zuerich, ETL I19 (Switzerland); Pal, Soumik, E-mail: soumik@math.washington.edu [University of Washington, Department of Mathematics (United States)
2011-04-15T23:59:59.000Z
We address stability of a class of Markovian discrete-time stochastic hybrid systems. This class of systems is characterized by the state-space of the system being partitioned into a safe or target set and its exterior, and the dynamics of the system being different in each domain. We give conditions for L{sub 1}-boundedness of Lyapunov functions based on certain negative drift conditions outside the target set, together with some more minor assumptions. We then apply our results to a wide class of randomly switched systems (or iterated function systems), for which we give conditions for global asymptotic stability almost surely and in L{sub 1}. The systems need not be time-homogeneous, and our results apply to certain systems for which functional-analytic or martingale-based estimates are difficult or impossible to get.
Sandia National Laboratories: atmospheric chemistry
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
and atmospheric chemistry that is expected to benefit auto and engine manufacturers, oil and gas utilities, and other industries that employ combustion models. A paper...
Large-scale optimal power flow: Effects of initialization, decoupling and discretization
Papalexopoulos, A.D.; Imparato, C.F.; Wu, F.F.
1989-08-01T23:59:59.000Z
The optimal power flow has entered a new era since the introduction of second-order methods. These methods have renewed hopes for its on-line application in Energy Management Systems. This paper reports on some of the results of tests of a second-order OPF method. The testing was conducted using a 1500 bus network, under a variety of loading conditions. Three issues were studied: Sensitivity of OPF solutions with respect to the starting points used in the solution; Accuracy of the active/reactive decoupled approach to OPF solution; Effects of discretization of transformer taps on the OPF solutions.
José Alfredo Cañizo
2007-11-19T23:59:59.000Z
Under the condition of detailed balance and some additional restrictions on the size of the coefficients, we identify the equilibrium distribution to which solutions of the discrete coagulation-fragmentation system of equations converge for large times, thus showing that there is a critical mass which marks a change in the behavior of the solutions. This was previously known only for particular cases as the generalized Becker-D\\"oring equations. Our proof is based on an inequality between the entropy and the entropy production which also gives some information on the rate of convergence to equilibrium for solutions under the critical mass.
Niehof, Jonathan T.; Morley, Steven K.
2012-01-01T23:59:59.000Z
We review and develop techniques to determine associations between series of discrete events. The bootstrap, a nonparametric statistical method, allows the determination of the significance of associations with minimal assumptions about the underlying processes. We find the key requirement for this method: one of the series must be widely spaced in time to guarantee the theoretical applicability of the bootstrap. If this condition is met, the calculated significance passes a reasonableness test. We conclude with some potential future extensions and caveats on the applicability of these methods. The techniques presented have been implemented in a Python-based software toolkit.
Atmospheric fogging in underground mine airways
Gillies, A.D.S.; Schimmelpfennig
1983-04-01T23:59:59.000Z
Loss of visibility due to the occurrence of atmospheric fogging in underground mine airways can lead to longer travel times and loss of production efficiency, an increase in the frequency of vehicular and foot traffic accidents and difficulty in checking rock surfaces for instability and loose material. Where hot and humid surface air meets colder underground air, conditions for fog formation may be present. Further, suspended particulate matter from diesel exhausts or stoping operations together with slow movement of air along passageways may contribute to formation. This study describes an investigation being undertaken with the cooperation of Kennecott's Ozark Lead Co. to identify causes of the problem.
Automatic Performance Optimization of the Discrete Fourier Transform
Franchetti, Franz
Automatic Performance Optimization of the Discrete Fourier Transform on Distributed Memory {franzf,pueschel}@ece.cmu.edu Abstract. This paper introduces a formal framework for automatically. Using a tagging mechanism and formula rewriting, we extend SPIRAL to automatically generate parallelized
A piecewise linear finite element discretization of the diffusion equation
Bailey, Teresa S
2006-10-30T23:59:59.000Z
In this thesis, we discuss the development, implementation and testing of a piecewise linear (PWL) continuous Galerkin finite element method applied to the threedimensional diffusion equation. This discretization is particularly interesting because...
Resolution of grain scale interactions using the Discrete Element Method
Johnson, Scott M. (Scott Matthew), 1978-
2006-01-01T23:59:59.000Z
Granular materials are an integral part of many engineering systems. Currently, a popular tool for numerically investigating granular systems is the Discrete Element Method (DEM). Nearly all implementations of the DEM, ...
Design of discrete-time filters for efficient implementation
Wei, Dennis
2011-01-01T23:59:59.000Z
The cost of implementation of discrete-time filters is often strongly dependent on the number of non-zero filter coefficients or the precision with which the coefficients are represented. This thesis addresses the design ...
Discrete Feature Approach for Heterogeneous Reservoir Production Enhancement
Dershowitz, William S.; Curran, Brendan; Einstein, Herbert; LaPointe, Paul; Shuttle, Dawn; Klise, Kate
2002-07-26T23:59:59.000Z
The report presents summaries of technology development for discrete feature modeling in support of the improved oil recovery (IOR) for heterogeneous reservoirs. In addition, the report describes the demonstration of these technologies at project study sites.
Switching Between Discrete and Continuous Models To Predict Genetic Activity
Weld, Daniel S.
Molecular biologists use a variety of models when they predict the behavior of genetic systems. A discrete model of the behavior of individual macromolecular elements forms the foundation for their theory of each system. ...
Direct measurement of yield stress of discrete materials
S. H. Ebrahimnazhad Rahbari; J. Vollmer; S. Herminghaus; M. Brinkmann
2012-06-09T23:59:59.000Z
We present a novel computational method for direct measurement of yield stress of discrete materials. The method is well-suited for the measurement of jamming phase diagram of a wide range of discrete particle systems such as granular materials, foams, and colloids. We further successfully apply the method to evaluate the jamming phase diagram of wet granular material in order to demonstrates the applicability of the model.
A Vertical Grid Module for Baroclinic Models of the Atmosphere
Drake, John B [ORNL
2008-04-01T23:59:59.000Z
The vertical grid of an atmospheric model assigns dynamic and thermo- dynamic variables to grid locations. The vertical coordinate is typically not height but one of a class of meteorological variables that vary with atmo- spheric conditions. The grid system is chosen to further numerical approx- imations of the boundary conditions so that the system is terrain following at the surface. Lagrangian vertical coordinates are useful in reducing the numerical errors from advection processes. That the choices will effect the numercial properties and accuracy is explored in this report. A MATLAB class for Lorentz vertical grids is described and applied to the vertical struc- ture equation and baroclinic atmospheric circulation. A generalized meteo- rolgoical coordinate system is developed which can support ?, isentropic ? vertical coordinate, or Lagrangian vertical coordinates. The vertical atmo- spheric column is a MATLAB class that includes the kinematic and ther- modynamic variables along with methods for computing geopoentials and terms relevant to a 3D baroclinc atmospheric model.
Space Science : Atmosphere Greenhouse Effect
Johnson, Robert E.
Space Science : Atmosphere Greenhouse Effect Part-5a Solar + Earth Spectrum IR Absorbers Grey Atmosphere Greenhouse Effect #12;Radiation: Solar and Earth Surface B"(T) Planck Ideal Emission Integrate and it emits Note: heat balance Fvis( = Fout = Te 4 z #12;(simple Greenhouse cont.) 0 1 2 3 4 Ground Space Top
An implicit finite element method for discrete dynamic fracture
Jobie M. Gerken
1999-12-01T23:59:59.000Z
A method for modeling the discrete fracture of two-dimensional linear elastic structures with a distribution of small cracks subject to dynamic conditions has been developed. The foundation for this numerical model is a plane element formulated from the Hu-Washizu energy principle. The distribution of small cracks is incorporated into the numerical model by including a small crack at each element interface. The additional strain field in an element adjacent to this crack is treated as an externally applied strain field in the Hu-Washizu energy principle. The resulting stiffness matrix is that of a standard plane element. The resulting load vector is that of a standard plane element with an additional term that includes the externally applied strain field. Except for the crack strain field equations, all terms of the stiffness matrix and load vector are integrated symbolically in Maple V so that fully integrated plane stress and plane strain elements are constructed. The crack strain field equations are integrated numerically. The modeling of dynamic behavior of simple structures was demonstrated within acceptable engineering accuracy. In the model of axial and transverse vibration of a beam and the breathing mode of vibration of a thin ring, the dynamic characteristics were shown to be within expected limits. The models dominated by tensile forces (the axially loaded beam and the pressurized ring) were within 0.5% of the theoretical values while the shear dominated model (the transversely loaded beam) is within 5% of the calculated theoretical value. The constant strain field of the tensile problems can be modeled exactly by the numerical model. The numerical results should therefore, be exact. The discrepancies can be accounted for by errors in the calculation of frequency from the numerical results. The linear strain field of the transverse model must be modeled by a series of constant strain elements. This is an approximation to the true strain field, so some error is expected.
Department of Electrical Engineering and Computer Science Discrete Event Systems Group
Tilbury, Dawn
Department of Electrical Engineering and Computer Science 1 Discrete Event Systems Group A Discrete 2000 #12;Department of Electrical Engineering and Computer Science 2 Discrete Event Systems Group of Electrical Engineering and Computer Science 3 Discrete Event Systems Group Requirements for Industrial
Bounds for the price of discrete arithmetic Asian options M. Vanmaele
Vanmaele, Michèle
on discrete averaging which is the normal specification in real contracts. Discrete arithmetic Asian optionsBounds for the price of discrete arithmetic Asian options M. Vanmaele , G. Deelstra , J. Liinev , J.Goovaerts@econ.kuleuven.ac.be, Tel. +32 16 326750. #12;Bounds for the price of discrete arithmetic Asian options Abstract
DIVISION OF MARINE AND ATMOSPHERIC CHEMISTRY
Shyu, Mei-Ling
DIVISION OF MARINE AND ATMOSPHERIC CHEMISTRY The missions of the Division of Marine and Atmospheric Chemistry (MAC) are to carry out broadly based research on the chemistry of the atmosphere and marine and stratosphere. Atmospheric Chemistry Research activities in atmospheric chemistry and modeling are diverse
A Wavelet-Based Methodology for Grinding Wheel Condition Monitoring
Liao, T. W. [Louisiana State University; Ting, C.F. [Louisiana State University; Qu, Jun [ORNL; Blau, Peter Julian [ORNL
2007-01-01T23:59:59.000Z
Grinding wheel surface condition changes as more material is removed. This paper presents a wavelet-based methodology for grinding wheel condition monitoring based on acoustic emission (AE) signals. Grinding experiments in creep feed mode were conducted to grind alumina specimens with a resinoid-bonded diamond wheel using two different conditions. During the experiments, AE signals were collected when the wheel was 'sharp' and when the wheel was 'dull'. Discriminant features were then extracted from each raw AE signal segment using the discrete wavelet decomposition procedure. An adaptive genetic clustering algorithm was finally applied to the extracted features in order to distinguish different states of grinding wheel condition. The test results indicate that the proposed methodology can achieve 97% clustering accuracy for the high material removal rate condition, 86.7% for the low material removal rate condition, and 76.7% for the combined grinding conditions if the base wavelet, the decomposition level, and the GA parameters are properly selected.
Global atmospheric chemistry: Integrating over fractional cloud cover
Neu, Jessica L; Prather, Michael J; Penner, Joyce E
2007-01-01T23:59:59.000Z
trace gases and atmospheric chemistry, in Climate Change2007 Global atmospheric chemistry: Integrating over2007), Global atmospheric chemistry: Integrating over
ATMOSPHERIC CHEMISTRY - RESPONSE TO HUMAN INFLUENCE
LOGAN, J; PRATHER, M; WOFSY, S; MCELROY, M
1978-01-01T23:59:59.000Z
Trans. II 70, 253. ATMOSPHERIC CHEMISTRY Clyne, M. A. A. &data for modelling atmospheric chemistry. NBS Technical NoteChem. 80, 2711. ATMOSPHERIC CHEMISTRY Sanadze, G. A. 1963 On
IMPROVED QUASISTEADYSTATEAPPROXIMATION METHODS FOR ATMOSPHERIC CHEMISTRY INTEGRATION #
Jay, Laurent O.
IMPROVED QUASISTEADYSTATEAPPROXIMATION METHODS FOR ATMOSPHERIC CHEMISTRY INTEGRATION # L. O. JAY QSSA are presented. Key words. atmospheric chemistry, sti# ordinary di#erential equations, quasi PII. S1064827595283033 1. Introduction. As our scientific understanding of atmospheric chemistry
Modeling Atmospheric Aerosols V. Rao Kotamarthi
Modeling Atmospheric Aerosols V. Rao Kotamarthi and Yan Feng Climate Research Section Environmental Science Division Argonne National Laboratory #12;Outline Atmospheric Aerosols and gas phase heterogeneous reactions Regional Scales and Atmospheric Aerosols Regional Scale Aerosols: Ganges Valley Aerosol
Blackwell, William Joseph, 1971-
2002-01-01T23:59:59.000Z
This thesis addresses the problem of retrieving the temperature profile of the Earth's atmosphere from overhead infrared and microwave observations of spectral radiance in cloudy conditions. The contributions of the thesis ...
Infrared Observations of Exoplanet Atmospheres
Crossfield, Ian James Mills
2012-01-01T23:59:59.000Z
However, atmospheres of cool planets can still be studiedvia outgassing as the planet cools (Rogers & Seager 2010).at low resolution) and the cool, low-mass planet GJ 1214b (
Environmental Chemistry II (Atmospheric Chemistry)
Dibble, Theodore
SYLLABUS FOR Environmental Chemistry II (Atmospheric Chemistry) FCH 511 Fall 2013 Theodore S/explaining the trends in J as a function of altitude and solar zenith angle. The second involves analyzing real
THE MARTIAN ATMOSPHERIC BOUNDARY LAYER
Spiga, Aymeric
THE MARTIAN ATMOSPHERIC BOUNDARY LAYER A. Petrosyan,1 B. Galperin,2 S. E. Larsen,3 S. R. Lewis,4 A [Haberle et al., 1993a; Larsen et al., 2002; Hinson et al., 2008]. At night, convection is inhibited
Atmospheric science and power production
Randerson, D. (ed.)
1984-07-01T23:59:59.000Z
This is the third in a series of scientific publications sponsored by the US Atomic Energy Commission and the two later organizations, the US Energy Research and Development Adminstration, and the US Department of Energy. The first book, Meteorology and Atomic Energy, was published in 1955; the second, in 1968. The present volume is designed to update and to expand upon many of the important concepts presented previously. However, the present edition draws heavily on recent contributions made by atmospheric science to the analysis of air quality and on results originating from research conducted and completed in the 1970s. Special emphasis is placed on how atmospheric science can contribute to solving problems relating to the fate of combustion products released into the atmosphere. The framework of this book is built around the concept of air-quality modeling. Fundamentals are addressed first to equip the reader with basic background information and to focus on available meteorological instrumentation and to emphasize the importance of data management procedures. Atmospheric physics and field experiments are described in detail to provide an overview of atmospheric boundary layer processes, of how air flows around obstacles, and of the mechanism of plume rise. Atmospheric chemistry and removal processes are also detailed to provide fundamental knowledge on how gases and particulate matter can be transformed while in the atmosphere and how they can be removed from the atmosphere. The book closes with a review of how air-quality models are being applied to solve a wide variety of problems. Separate analytics have been prepared for each chapter.
Laser Atmospheric Studies with VERITAS
C. M. Hui; for the VERITAS collaboration
2007-09-25T23:59:59.000Z
As a calibrated laser pulse propagates through the atmosphere, the amount of Rayleigh-scattered light arriving at the VERITAS telescopes can be calculated precisely. This technique was originally developed for the absolute calibration of ultra-high-energy cosmic-ray fluorescence telescopes but is also applicable to imaging atmospheric Cherenkov telescopes (IACTs). In this paper, we present two nights of laser data taken with the laser at various distances away from the VERITAS telescopes and compare it to Rayleigh scattering simulations.
Representative Atmospheric Plume Development for Elevated Releases
Eslinger, Paul W.; Lowrey, Justin D.; McIntyre, Justin I.; Miley, Harry S.; Prichard, Andrew W.
2014-03-03T23:59:59.000Z
An atmospheric explosion of a low-yield nuclear device will produce a large number of radioactive isotopes, some of which can be measured with airborne detection systems. However, properly equipped aircraft may not arrive in the region where an explosion occurred for a number of hours after the event. Atmospheric conditions will have caused the radioactive plume to move and diffuse before the aircraft arrives. The science behind predicting atmospheric plume movement has advanced enough that the location of the maximum concentrations in the plume can be determined reasonably accurately in real time, or near real time. Given the assumption that an aircraft can follow a plume, this study addresses the amount of atmospheric dilution expected to occur in a representative plume as a function of time past the release event. The approach models atmospheric transport of hypothetical releases from a single location for every day in a year using the publically available HYSPLIT code. The effective dilution factors for the point of maximum concentration in an elevated plume based on a release of a non-decaying, non-depositing tracer can vary by orders of magnitude depending on the day of the release, even for the same number of hours after the release event. However, the median of the dilution factors based on releases for 365 consecutive days at one site follows a power law relationship in time, as shown in Figure S-1. The relationship is good enough to provide a general rule of thumb for estimating typical future dilution factors in a plume starting at the same point. However, the coefficients of the power law function may vary for different release point locations. Radioactive decay causes the effective dilution factors to decrease more quickly with the time past the release event than the dilution factors based on a non-decaying tracer. An analytical expression for the dilution factors of isotopes with different half-lives can be developed given the power law expression for the non-decaying tracer. If the power-law equation for the median dilution factor, Df, based on a non-decaying tracer has the general form Df=a?×t?^(-b) for time t after the release event, then the equation has the form Df=e^(-?t)×a×t^(-b) for a radioactive isotope, where ? is the decay constant for the isotope.
Discrete canonical analysis of three dimensional gravity with cosmological constant
J. Berra-Montiel; J. E. Rosales-Quintero
2014-06-03T23:59:59.000Z
We discuss the interplay between standard canonical analysis and canonical discretization in three-dimensional gravity with cosmological constant. By using the Hamiltonian analysis, we find that the continuum local symmetries of the theory are given by the on-shell space-time diffeomorphisms, which at the action level, corresponds to the Kalb-Ramond transformations. At the time of discretization, although this symmetry is explicitly broken, we prove that the theory still preserves certain gauge freedom generated by a constant curvature relation in terms of holonomies and the Gauss's law in the lattice approach.
Discrete Cosmological Self-Similarity And Delta Scuti Stars
R. L. Oldershaw
2008-10-08T23:59:59.000Z
Within the context of a fractal paradigm that emphasizes nature's well-stratified hierarchical organization, the delta Scuti class of variable stars is investigated for evidence of discrete cosmological self-similarity. Methods that were successfully applied to the RR Lyrae class of variable stars are used to identify Atomic Scale analogues to delta Scuti stars and their relevant range of energy levels. The mass, pulsation mode and fundamental oscillation period of a well-studied delta Scuti star are shown to be quantitatively self-similar to the counterpart parameters of a uniquely identified Atomic Scale analogue. Several additional tests confirm the specificity of the discrete fractal relationship.
Computer aided analysis and synthesis for discrete robust control systems
Setijawan, Bambang
1994-01-01T23:59:59.000Z
of an interval discrete system. . 4 Nyquist plot of the system with a constant controller k = -3. . . . . 5 Definition of encirclement. . Page 27 28 30 6 Definition of enclosed points and regions. . 7 Definition of the number of encirclement and enclosure... unstable 1 Re marginally stable Fig. 1. Stability region for discrete time systems A general control system is presented in the following figure, r e + controller C(z) PLANT G(z) Fig. 2. A general form of control systems Any physical process...
Millimeter Wavelength Brightness Fluctuations of the Atmosphere Above the South Pole
Bussmann, R S; Kuo, C L
2004-01-01T23:59:59.000Z
We report measurements of the millimeter wavelength brightness fluctuations produced by the atmosphere above the South Pole made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR). The data span the 2002 Austral winter during which ACBAR was mounted on the Viper telescope at the South Pole. We recover the atmospheric signal in the presence of instrument noise by calculating the correlation between signals from distinct elements of the ACBAR bolometer array. With this method, it is possible to measure atmospheric brightness fluctuations with high SNR even under the most stable atmospheric conditions. The observed atmospheric signal is characterized by the parameters of the Komolgorov-Taylor (KT) model, which are the amplitude and power law exponent describing the atmospheric power spectrum, and the two components of the wind angular velocity at the time of the observation. The KT model is typically a good description of the observed fluctuations, and fits to the data produce values of the Komolgorov...
Chemistry of Atmospheric Brown Carbon Alexander Laskin,*,
Nizkorodov, Sergey
Chemistry of Atmospheric Brown Carbon Alexander Laskin,*, Julia Laskin,*, and Sergey A. Nizkorodov fraction of atmospheric aerosol and has profound effects on air quality, atmospheric chemistry, and climate of radiation through Earth's atmosphere. The cloud albedo effect, Special Issue: 2015 Chemistry in Climate
Atmospheric benzenoid emissions from plants rival those from fossil fuels
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Misztal, P. K.; Hewitt, C. N.; Wildt, J.; Blande, J. D.; Eller, A. S.D.; Fares, S.; Gentner, D. R.; Gilman, J. B.; Graus, M.; Greenberg, J.; et al
2015-07-13T23:59:59.000Z
Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functionsmore »of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.« less
An active atmospheric methane sink in high Arctic mineral cryosols
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lau, Maggie C.Y.; Stackhouse, B.; Layton, Alice C.; Chauhan, Archana; Vishnivetskaya, T. A.; Chourey, Karuna; Mykytczuk, N. C.S.; Bennett, Phil C.; Lamarche-Gagnon, G.; Burton, N.; et al
2015-01-01T23:59:59.000Z
The transition of Arctic carbon-rich cryosols into methane (CH?)-emitting wetlands due to global warming is a rising concern. However, the spatially predominant mineral cryosols and their CH? emission potential are poorly understood. Fluxes measured in situ and estimated under laboratory conditions coupled with -omics analysis indicate (1) mineral cryosols in the Canadian high Arctic contain atmospheric CH?-oxidizing bacteria; (2) the atmospheric CH? uptake flux increases with ground temperature; and, as a result, (3) the atmospheric CH? sink strength will increase by a factor of 5-30 as the Arctic warms by 5-15 °C over a century. We demonstrated that acidic mineralmore »cryosols have previously unrecognized potential of negative CH? feedback.« less
Semiclassical energy conditions
Martin-Moruno, Prado
2013-01-01T23:59:59.000Z
We present and develop several nonlinear energy conditions suitable for use in the semiclassical regime. In particular, we consider the recently formulated "flux energy condition" (FEC), and the novel "trace-of-square" (TOSEC) and "determinant" (DETEC) energy conditions. As we shall show, these nonlinear energy conditions behave much better than the classical linear energy conditions in the presence of semiclassical quantum effects. Moreover, whereas the quantum extensions of these nonlinear energy conditions seem to be quite widely satisfied as one enters the quantum realm, analogous quantum extensions are generally not useful for the linear classical energy conditions.
GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method
Gong Chunye, E-mail: gongchunye@gmail.com [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Liu Jie, E-mail: liujie@nudt.edu.cn [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Chi Lihua [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Huang Haowei [Institut fuer Informatik, Technische Universitaet Muenchen, D-85748 Garching, Munich (Germany); Fang Jingyue [School of Physics and Mathematics, National University of Defense Technology, Changsha 410073 (China); Gong Zhenghu [School of Computer Science, National University of Defense Technology, Changsha 410073 (China)
2011-07-01T23:59:59.000Z
Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, inhomogeneous Boltzmann transport equation. The numerical solution to the Boltzmann equation involves the discrete ordinates (S{sub n}) method and the procedure of source iteration. In this paper, we present a GPU accelerated simulation of one energy group time-independent deterministic discrete ordinates particle transport in 3D Cartesian geometry (Sweep3D). The performance of the GPU simulations are reported with the simulations of vacuum boundary condition. The discussion of the relative advantages and disadvantages of the GPU implementation, the simulation on multi GPUs, the programming effort and code portability are also reported. The results show that the overall performance speedup of one NVIDIA Tesla M2050 GPU ranges from 2.56 compared with one Intel Xeon X5670 chip to 8.14 compared with one Intel Core Q6600 chip for no flux fixup. The simulation with flux fixup on one M2050 is 1.23 times faster than on one X5670.
Error Exponent for Discrete Memoryless Multiple-Access Channels
Anastasopoulos, Achilleas
Error Exponent for Discrete Memoryless Multiple-Access Channels by Ali Nazari A dissertation Bayraktar Associate Professor Jussi Keppo #12;c Ali Nazari 2011 All Rights Reserved #12;To my parents. ii Becky Turanski, Nancy Goings, Michele Feldkamp, Ann Pace, Karen Liska and Beth Lawson for efficiently
DISCRETE-CONTINUUM MODELING OF METAL MATRIX COMPOSITES PLASTICITY
Devincre, Benoit
. For this reason, the pre- diction of the plastic properties of Metal Matrix Composites (MMCs) is some- times for plastic properties. On the one hand, the FE code treats the boundary value problem and cares of the conDISCRETE-CONTINUUM MODELING OF METAL MATRIX COMPOSITES PLASTICITY S. Groh1, B. Devincre1, F. Feyel2
Physics in discrete spaces (A): Space-Time organization
P. Peretto
2010-12-29T23:59:59.000Z
We put forward a model of discrete physical space that can account for the structure of space- time, give an interpretation to the postulates of quantum mechanics and provide a possible explanation to the organization of the standard model of particles.
Continuum Representation for Simulating Discrete Events of Battery Operation
Panchagnula, Mahesh
the discrete events in the cycling studies of lithium-ion batteries as a continuum event has been proposed-order pseudo-two-dimensional lithium-ion battery model that has several coupled and nonlinear partial that are currently fol- lowed for the modeling of charge/discharge cycles of lithium-ion batteries involve different
Inverses of Multivariate Polynomial Matrices using Discrete Convolution
Young, R. Michael
Inverses of Multivariate Polynomial Matrices using Discrete Convolution R. Lobo Dept. of Elec Raleigh, NC 27695 Abstract-- A new method for inversion of rectangular matrices in a multivariate to multivariate polynomial system of equations is the subject of intensive research and has major applications
Integrating a discrete motion model into GMM based background subtraction
Wolf, Christian
consecutive frames minimizing a global energy function taking into account spatial and temporal re- lationships. A discrete approximative optical-flow like motion model is integrated into the energy function, for instance for track- ing algorithms. Most existing methods build an explicit background model either using
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
Girardi, I; Stuart, Alexander J; Titov, A V
2015-01-01T23:59:59.000Z
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\
Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries
I. Girardi; S. T. Petcov; Alexander J. Stuart; A. V. Titov
2015-09-08T23:59:59.000Z
Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group $G_f$, and that $G_f$ is broken to specific residual symmetries $G_e$ and $G_\
Double-distribution-function discrete Boltzmann model for combustion
Chuandong Lin; Aiguo Xu; Guangcai Zhang; Yingjun Li
2015-06-21T23:59:59.000Z
A 2-dimensional discrete Boltzmann model for combustion is presented. Mathematically, the model is composed of two coupled discrete Boltzmann equations for two species and a phenomenological evolution equation for chemical reaction process. Physically, the model is equivalent to a Navier-Stokes model supplemented by a coarse-grained model for the thermodynamic nonequilibrium behaviours. This model adopts $16$ discrete velocities. It works for both subsonic and supersonic combustion phenomena with flexible specific heat ratio. To discuss the physical accuracy of the coarse-grained model for nonequilibrium behaviours, three other discrete velocity models are used for comparisons. Numerical results are compared with analytical solutions based on both the first-order and second-order truncations of the distribution function. It is confirmed that the physical accuracy increases with the increasing moment relations needed by nonequlibrium manifestations. Furthermore, a criterion of transition from incomplete to complete combustion is obtained. Compared with the single distribution function model, this model can simulate incomplete combustion, decomposition and combination reactions.
Topological horseshoes in travelling waves of discretized nonlinear wave equations
Chen, Yi-Chiuan, E-mail: YCChen@math.sinica.edu.tw [Institute of Mathematics, Academia Sinica, Taipei 10617, Taiwan (China)] [Institute of Mathematics, Academia Sinica, Taipei 10617, Taiwan (China); Chen, Shyan-Shiou, E-mail: sschen@ntnu.edu.tw [Department of Mathematics, National Taiwan Normal University, Taipei 11677, Taiwan (China)] [Department of Mathematics, National Taiwan Normal University, Taipei 11677, Taiwan (China); Yuan, Juan-Ming, E-mail: jmyuan@pu.edu.tw [Department of Financial and Computational Mathematics, Providence University, Shalu, Taichung 43301, Taiwan (China)] [Department of Financial and Computational Mathematics, Providence University, Shalu, Taichung 43301, Taiwan (China)
2014-04-15T23:59:59.000Z
Applying the concept of anti-integrable limit to coupled map lattices originated from space-time discretized nonlinear wave equations, we show that there exist topological horseshoes in the phase space formed by the initial states of travelling wave solutions. In particular, the coupled map lattices display spatio-temporal chaos on the horseshoes.
DISCRETE AND CONTINUOUS Website: http://AIMsciences.org DYNAMICAL SYSTEMS
Shiau, LieJune
well known fact: When there is dry friction, the force necessary to put the system into motion. 806Â815 OPERATOR SPLITTING METHOD FOR FRICTION CONSTRAINED DYNAMICAL SYSTEMS LieJune Shiau Department-discretization of those relations mod- eling a class of dynamical systems with friction was discussed. The main goal
Cryptanalyzing a discrete-time chaos synchronization secure communication system
Gonzalo Alvarez; Fausto Montoya; Miguel Romera; Gerardo Pastor
2003-11-21T23:59:59.000Z
This paper describes the security weakness of a recently proposed secure communication method based on discrete-time chaos synchronization. We show that the security is compromised even without precise knowledge of the chaotic system used. We also make many suggestions to improve its security in future versions.
Energy-Efficient Discrete Cosine Transform on Ronald Scrofano
Jang, Ju-Wook
Energy-Efficient Discrete Cosine Transform on FPGAs Ronald Scrofano Department of Computer Science is brought to mobile devices, it becomes important that it is possible to calculate the DCT in an energy-efficient the DCT with a linear array of PEs. This design is optimized for energy efficiency. We analyze the energy
Multivariable Discrete Time Repetitive Control System Hammoud Saari1
Boyer, Edmond
Multivariable Discrete Time Repetitive Control System Hammoud Saari1 and Bernard Caron2 1 SETRAM, France hammoud.saari@yahoo.fr, bernard.caron@univ-savoie.fr Keywords: Repetitive Control, Multivariable), Ahn et al. (2007) and Saari et al. (2010)). Most of their works were focused on the problem
The Discrete Wavelet Transform and Wavelet Synopses Minos Garofalakis
Garofalakis, Minos
The Discrete Wavelet Transform and Wavelet Synopses Minos Garofalakis Technical University of Crete minos@acm.org SYNONYMS None. DEFINITION Wavelets are a useful mathematical tool for hierarchically decomposing functions in ways that are both efficient and theoretically sound. Broadly speaking, the wavelet
Spectral discretization of Darcy's equations with pressure dependent porosity
Paris-Sud XI, Université de
Spectral discretization of Darcy's equations with pressure dependent porosity by Mejdi Aza¨iez1 and the pressure p of the fluid. This system is an extension of Darcy's equations, which model the flow of the resulting system of equations which takes into account the axisymmetry of the domain and of the flow. We
Mortar spectral element discretization of Darcy's equations in nonhomogeneous medium
Paris-Sud XI, Université de
Mortar spectral element discretization of Darcy's equations in nonhomogeneous medium Mouna Daadaa Cedex 05 France. daadaa@ann.jussieu.fr 4 mai 2010 Abstract : We consider Darcy's equations. They turn out to be in good coherency with the theoretical results. R´esum´e : Les ´equations de Darcy mod
Discrete wave turbulence of rotational capillary water waves
Adrian Constantin; Elena Kartashova; Erik Wahlén
2010-05-12T23:59:59.000Z
We study the discrete wave turbulent regime of capillary water waves with constant non-zero vorticity. The explicit Hamiltonian formulation and the corresponding coupling coefficient are obtained. We also present the construction and investigation of resonance clustering. Some physical implications of the obtained results are discussed.
Generic Average Modeling and Simulation of Discrete Controllers
modeling of discrete controllers for PWM power conversion systems. The method applies a section be advantageous to have the capability of running AC analysis of digitally controlled power systems on a general the simulation of digitally controlled power conversion systems on general-purpose circuit simulators
Verification in Loosely Synchronous Queue-Connected Discrete Timed Automata
Dang, Zhe
, the expressive power of timed automata has many limitations in modeling, since many real-time systems are simply. We look at a model of a queue system that consists of the following components: 1. Two discrete timed model for investigating verification problems of real-time sys- tems (see [1, 30] for surveys). However
Verification in Loosely Synchronous QueueConnected Discrete Timed Automata ?
Dang, Zhe
, the expressive power of timed automata has many limitations in modeling, since many realÂtime systems are simply. We look at a model of a queue system that consists of the following components: 1. Two discrete timed model for investigating verification problems of realÂtime sysÂ tems (see [1, 30] for surveys). However
Nash Equilibria in Discrete Routing Games with Convex Latency Functions
Mavronicolas, Marios
Nash Equilibria in Discrete Routing Games with Convex Latency Functions Martin Gairing Thomas L is determined by an arbitrary non-decreasing, non-constant and convex latency function . In a Nash equilib- rium on the link it chooses. To evaluate Nash equilibria, we formulate Social Cost as the sum of the users
Cumulant expansions for atmospheric flows
Ait-Chaalal, Farid; Meyer, Bettina; Marston, J B
2015-01-01T23:59:59.000Z
The equations governing atmospheric flows are nonlinear, and consequently the hierarchy of cumulant equations is not closed. But because atmospheric flows are inhomogeneous and anisotropic, the nonlinearity may manifests itself only weakly through interactions of mean fields with disturbances such as thermals or eddies. In such situations, truncations of the hierarchy of cumulant equations hold promise as a closure strategy. We review how truncations at second order can be used to model and elucidate the dynamics of turbulent atmospheric flows. Two examples are considered. First, we study the growth of a dry convective boundary layer, which is heated from below, leading to turbulent upward energy transport and growth of the boundary layer. We demonstrate that a quasilinear truncation of the equations of motion, in which interactions of disturbances among each other are neglected but interactions with mean fields are taken into account, can successfully capture the growth of the convective boundary layer. Seco...
Oscillations of solar atmosphere neutrinos
G. L. Fogli; E. Lisi; A. Mirizzi; D. Montanino; P. D. Serpico
2006-11-10T23:59:59.000Z
The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations (in vacuum and in matter) on solar atmosphere neutrinos, and calculate their observable fluxes at Earth, as well as their event rates in a kilometer-scale detector in water or ice. We find that peculiar three-flavor oscillation effects in matter, which can occur in the energy range probed by solar atmosphere neutrinos, are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, we find that the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged ``vacuum'' oscillations, dominated by a single mixing parameter (the angle theta_23).
Fault tolerant control allocation in systems with fixed magnitude discrete controls
Marwaha, Monika
2009-05-15T23:59:59.000Z
as discrete controls. However, discrete controls constitute a different class of problems than proportional controls as they can take only binary values, unlike proportional controls which can take many values. Two nonlinear control laws based on Structured...
Discrete dragline attachment induces aggregation in spiderlings of a solitary species
Theraulaz, Guy
Discrete dragline attachment induces aggregation in spiderlings of a solitary species RAPHAEL and the experimental data shows that the discrete pattern of silk dragline attachment is the key mechanism involved
Discrete Applied Mathematics 154 (2006) 16331639 www.elsevier.com/locate/dam
Hartke, Stephen
2006-01-01T23:59:59.000Z
Discrete Applied Mathematics 154 (2006) 16331639 www.elsevier.com/locate/dam Note The elimination. doi:10.1016/j.dam.2005.11.009 #12;1634 Stephen G. Hartke / Discrete Applied Mathematics 154 (2006
Limited Model Information Control Design for Linear Discrete-Time Systems with Stochastic Parameters
Johansson, Karl Henrik
Limited Model Information Control Design for Linear Discrete-Time Systems with Stochastic systems with stochastically varying parameters. Recently, there have been studies in optimal control subsystems' parameters. There have been many studies in optimal control design for linear discrete
A discontinuous least-squares spatial discretization for the sn equations
Zhu, Lei
2009-05-15T23:59:59.000Z
In this thesis, we develop and test a fundamentally new linear-discontinuous least-squares (LDLS) method for spatial discretization of the one-dimensional (1-D) discrete-ordinates (SN) equations. This new scheme is based ...
Friedland, Lazar
Multiphase autoresonant excitations in discrete nonlinear Schrödinger systems Y. Gopher and L September 2005 Large amplitude, multiphase solutions of periodic discrete nonlinear Schrödinger NLS systems of an external parameter driving frequency . Numerical examples of excitation of multiphase waves and periodic
Shamir, Ron
Discrete Mathematics: Methods and Challenges Noga Alon Abstract Combinatorics is a fundamental connection between Discrete Mathematics and Theoretical Computer Science, and the rapid development two centuries. The tight connection between Discrete Mathematics and Theoretical Computer Science
Sebastian Schunert; Yousry Y. Azmy; Damien Fournier
2011-05-01T23:59:59.000Z
We present a comprehensive error estimation of four spatial discretization schemes of the two-dimensional Discrete Ordinates (SN) equations on Cartesian grids utilizing a Method of Manufactured Solution (MMS) benchmark suite based on variants of Larsen’s benchmark featuring different orders of smoothness of the underlying exact solution. The considered spatial discretization schemes include the arbitrarily high order transport methods of the nodal (AHOTN) and characteristic (AHOTC) types, the discontinuous Galerkin Finite Element method (DGFEM) and the recently proposed higher order diamond difference method (HODD) of spatial expansion orders 0 through 3. While AHOTN and AHOTC rely on approximate analytical solutions of the transport equation within a mesh cell, DGFEM and HODD utilize a polynomial expansion to mimick the angular flux profile across each mesh cell. Intuitively, due to the higher degree of analyticity, we expect AHOTN and AHOTC to feature superior accuracy compared with DGFEM and HODD, but at the price of potentially longer grind times and numerical instabilities. The latter disadvantages can result from the presence of exponential terms evaluated at the cell optical thickness that arise from the semianalytical solution process. This work quantifies the order of accuracy and the magnitude of the error of all four discretization methods for different optical thicknesses, scattering ratios and degrees of smoothness of the underlying exact solutions in order to verify or contradict the aforementioned intuitive expectation.
A coarse entropy-rigidity theorem and discrete length-volume inequalities
Kinneberg, Kyle Edward
2014-01-01T23:59:59.000Z
A discrete length-volume inequality . . . . . . . .v 3 Length-volume inequalities revisitedlength-volume inequality for cubes . . . . . . . . . . . .
Pulsed atmospheric fluidized bed combustion
Not Available
1992-08-01T23:59:59.000Z
The general specifications for a Pulsed Atmospheric Fluidized Bed Combustor Design Report (PAFBC) plant are presented. The design tasks for the PAFBC are described in the following areas: Coal/Limestone preparation and feed system; pulse combustor; fluidized bed; boiler parts; and ash handling system.
An Isometric Dynamics for a Causal Set Approach to Discrete Quantum Gravity
Stan Gudder
2014-09-12T23:59:59.000Z
We consider a covariant causal set approach to discrete quantum gravity. We first review the microscopic picture of this approach. In this picture a universe grows one element at a time and its geometry is determined by a sequence of integers called the shell sequence. We next present the macroscopic picture which is described by a sequential growth process. We introduce a model in which the dynamics is governed by a quantum transition amplitude. The amplitude satisfies a stochastic and unitary condition and the resulting dynamics becomes isometric. We show that the dynamics preserves stochastic states. By "doubling down" on the dynamics we obtain a unitary group representation and a natural energy operator. These unitary operators are employed to define canonical position and momentum operators.
Numerical study of natural convection in a vertical porous annulus with discrete heating
Lopez, John M.
Numerical study of natural convection in a vertical porous annulus with discrete heating M. Sankar online 20 December 2010 Keywords: Natural convection Annulus Discrete heating Porous medium Radii ratio to discrete heating. The outer wall is maintained iso- thermally at a lower temperature, while the top
A discrete fourth-order Lidstone problem with parameters Douglas R. Anderson a,*, Feliz Minhs b
Anderson, Douglas R.
A discrete fourth-order Lidstone problem with parameters Douglas R. Anderson a,*, Feliz Minhós b Symmetric Green's function Fixed points Fourth-order Discrete Beam Lidstone Semipositone a b s t r a c discrete fourth-order Lidstone boundary value problem with dependence on two parameters are given, using
Paris-Sud XI, Université de
DISCRETE EXTENDED KALMAN FILTER ON LIE GROUPS Guillaume Bourmaud, Rémi Mégret, Audrey Giremus, 33405 Talence cedex, France ABSTRACT In this paper, we generalize the Discrete Extended Kalman Filter (D called Discrete Extended Kalman Filter on Lie Groups (D- LG-EKF). It assumes that the posterior
Smith, Alice E.
is not known. Instead, we consider the more realistic assumption of discrete cost-reliability data sets expressions for cost-reliability curves, we consider discrete cost-reliability data sets for each componentOPTIMAL RELIABILITY ALLOCATION IN SERIES-PARALLEL SYSTEMS FROM COMPONENTS' DISCRETE COST
CERNA WORKING PAPER SERIES Patent quality and value in discrete and cumulative innovation
Paris-Sud XI, Université de
1 CERNA WORKING PAPER SERIES Patent quality and value in discrete and cumulative innovation Justus,version2-16Nov2010 #12;2 Patent Quality and Value in Discrete and Cumulative Innovation Cerna Working the relationship between patent quality and patent value in discrete and cumulative innovation. Using factor
Controllers for Discrete Event Systems via P. Madhusudan 1 and P. S. Thiagarajan 2 ?
Parthasarathy, Madhusudan
Controllers for Discrete Event Systems via Morphisms P. Madhusudan 1 and P. S. Thiagarajan 2 ? 1 the problem of synthesising controllers for discrete event systems. Traditionally this problem is tackled therein. From the controlÂtheoretic perspective, the modelling of discreteÂevent systems (DES
Finite-Time Stability of Discrete-Time Nonlinear Systems: Analysis and Design
Finite-Time Stability of Discrete-Time Nonlinear Systems: Analysis and Design S. Mastellone, P. Dorato, C. T. Abdallah Abstract-- Finite-time stability of nonlinear discrete-time systems is studied we propose a new analysis result for fi- nite time stability of deterministic and stochastic discrete
Averages along polynomial sequences in discrete nilpotent groups: singular Radon transforms
Ionescu, Alexandru D; Wainger, Stephen
2012-01-01T23:59:59.000Z
We consider a class of operators defined by taking averages along polynomial sequences in discrete nilpotent groups. In this paper we prove $L^2$ boundedness of discrete singular Radon transforms along general polynomial sequences in discrete nilpotent groups of step 2.
Vanderbei, Robert J., E-mail: rvdb@princeton.edu [Princeton University, Department of Operations Research and Financial Engineering (United States); P Latin-Small-Letter-Dotless-I nar, Mustafa C., E-mail: mustafap@bilkent.edu.tr [Bilkent University, Department of Industrial Engineering (Turkey); Bozkaya, Efe B. [Sabanc Latin-Small-Letter-Dotless-I University, Faculty of Administrative Sciences (Turkey)] [Sabanc Latin-Small-Letter-Dotless-I University, Faculty of Administrative Sciences (Turkey)
2013-02-15T23:59:59.000Z
An American option (or, warrant) is the right, but not the obligation, to purchase or sell an underlying equity at any time up to a predetermined expiration date for a predetermined amount. A perpetual American option differs from a plain American option in that it does not expire. In this study, we solve the optimal stopping problem of a perpetual American option (both call and put) in discrete time using linear programming duality. Under the assumption that the underlying stock price follows a discrete time and discrete state Markov process, namely a geometric random walk, we formulate the pricing problem as an infinite dimensional linear programming (LP) problem using the excessive-majorant property of the value function. This formulation allows us to solve complementary slackness conditions in closed-form, revealing an optimal stopping strategy which highlights the set of stock-prices where the option should be exercised. The analysis for the call option reveals that such a critical value exists only in some cases, depending on a combination of state-transition probabilities and the economic discount factor (i.e., the prevailing interest rate) whereas it ceases to be an issue for the put.
Zheng, Zhongquan C.; Wei, Zhenglun A.; Bennett, James S.; Yang, Xiaofan
2012-12-11T23:59:59.000Z
In simulating fluid/solid-particle multiphase -flows, various methods are available. One approach is the combined Euler-Lagrange method, which simulates the fluid phase flow in the Eulerian framework and the discrete phase (particle) motion in the Lagrangian framework simultaneously. The Lagrangian approach, where particle motion is determined by the current state of the fluid phase flow, is also called the discrete phase model (DPM), in the context of numerical flow simulation. In this method, the influence of the particle motions on the fluid flow can be included (two-way interactions) but are more commonly excluded (one-way interactions, when the discrete phase concentration is dilute. The other approach is to treat the particle number concentration as a continuous species, a necessarily passive quantity determined by the fluid flow, with no influences from the particles on the fluid flow (one-way interactions only), except to the extent the discrete phase “continuum” alters the overall fluid properties, such as density. In this paper, we compare these two methods with experimental data for an indoor environmental chamber. The effects of injection particle numbers and the related boundary conditions are investigated. In the Euler-Lagrange interaction or DPM model for incompressible flow, the Eulerian continuous phase is governed by the Reynolds-averaged N-S (RANS) equations. The motions of particles are governed by Newton’s second law. The effects of particle motions are communicated to the continuous phase through a force term in the RANS equations. The second formulation is a pure Eulerian type, where only the particle-number concentration is addressed, rather than the motion of each individual particle. The fluid flow is governed by the same RANS equations without the particle force term. The particle-number concentration is simulated by a species transport equation. Comparisons among the models and with experimental and literature data are presented. Particularly, results with different numbers of released particles in the DPM will be investigated.
The discrete Kalman filtering approach for seismic signals deconvolution
Kurniadi, Rizal; Nurhandoko, Bagus Endar B. [Departement of Physics Intitut Teknologi Bandung, Jl. Ganesha 10 Bandung (Indonesia)
2012-06-20T23:59:59.000Z
Seismic signals are a convolution of reflectivity and seismic wavelet. One of the most important stages in seismic data processing is deconvolution process; the process of deconvolution is inverse filters based on Wiener filter theory. This theory is limited by certain modelling assumptions, which may not always valid. The discrete form of the Kalman filter is then used to generate an estimate of the reflectivity function. The main advantage of Kalman filtering is capability of technique to handling continually time varying models and has high resolution capabilities. In this work, we use discrete Kalman filter that it was combined with primitive deconvolution. Filtering process works on reflectivity function, hence the work flow of filtering is started with primitive deconvolution using inverse of wavelet. The seismic signals then are obtained by convoluting of filtered reflectivity function with energy waveform which is referred to as the seismic wavelet. The higher frequency of wavelet gives smaller wave length, the graphs of these results are presented.
Implementation of Quantum and Classical Discrete Fractional Fourier Transforms
Steffen Weimann; Armando Perez-Leija; Maxime Lebugle; Robert Keil; Malte Tichy; Markus Gräfe; Rene Heilmann; Stefan Nolte; Hector Moya-Cessa; Gregor Weihs; Demetrios N. Christodoulides; Alexander Szameit
2015-07-31T23:59:59.000Z
Fourier transforms are ubiquitous mathematical tools in basic and applied sciences. We here report classical and quantum optical realizations of the discrete fractional Fourier transform, a generalization of the Fourier transform. In the integrated configuration used in our experiments, the order of the transform is mapped onto the longitudinal coordinate, thus opening up the prospect of simultaneously observing all Transformation orders. In the context of classical optics, we implement discrete fractional Fourier transforms, both integer and fractional, of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to transform separable and highly entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools, such as quantum chemistry and biology, physics and mathematics.
Global discretization of continuous attributes as preprocessing for machine learning
Chmielewski, M. R.; Grzymala-Busse, Jerzy W.
1996-11-01T23:59:59.000Z
continuous attribute is partitioning its domain into equal width intervals is called Equal Interval Width Method. A method of attribute discretization through adaptive discretization was proposed in [3]. The domain of an attribute is first partitioned... Interval Frequency Class Analysis Width per Interval Entropy Method GM 68.0 59.0 73.0 69.0 rocks 57.5 54.2 55.6 53.0 iris 91.5 86.7 82.0 95.3 bank 77.3 95.5 84.9 97.0 hsv-r 42.5 35.8 46.7 48.3 bupa 41.9 39.7 41.3 42.5 glass 54.7 49.5 56.1 60.3 wave 99.4 99...
A study of discrete and continuum joint modeling techniques
Jung, J.; Brown, S.R.
1992-05-01T23:59:59.000Z
This paper presents the results of a numerical and experimental study in which finite element and discrete element techniques were used to analyze a layered polycarbonate plate model subjected to uniaxial compression. Also, the two analysis techniques were used to compute the response of an eight meter diameter drift in jointed-rock. The drift was subjected to in-situ and far-field induced thermal stresses. The finite element analyses used a continuum rock model to represent the jointed-rock. A comparison of the analyses showed that the finite element continuum joint model consistently predicted less joint slippage than did the discrete element analyses, although far-field displacements compared well.
Directed assembly of discrete gold nanoparticle groupings usingbranched DNA scaffolds
Claridge, Shelley A.; Goh, Sarah L.; Frechet, Jean M.J.; Williams, Shara C.; Micheel, Christine M.; Alivisatos, A. Paul
2004-09-14T23:59:59.000Z
The concept of self-assembled dendrimers is explored for the creation of discrete nanoparticle assemblies. Hybridization of branched DNA trimers and nanoparticle-DNA conjugates results in the synthesis of nanoparticle trimer and tetramer complexes. Multiple tetramer architectures are investigated, utilizing Au-DNA conjugates with varying secondary structural motifs. Hybridization products are analyzed by gel electrophoresis, and discrete bands are observed corresponding to structures with increasing numbers of hybridization events. Samples extracted from each band are analyzed by transmission electron microscopy, and statistics compiled from micrographs are used to compare assembly characteristics for each architecture. Asymmetric structures are also produced in which both 5 and 10 nm Au particles are assembled on branched scaffolds.
Quantum Mechanics and Discrete Time from "Timeless" Classical Dynamics
H. -T. Elze
2003-07-03T23:59:59.000Z
We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. - This is motivated by the ``timeless'' reparametrization invariant model of a relativistic particle with two compactified extradimensions. In this example, discrete physical time is constructed based on quasi-local observables. - Generally, employing the path-integral formulation of classical mechanics developed by Gozzi et al., we show that these deterministic classical systems can be naturally described as unitary quantum mechanical models. The emergent quantum Hamiltonian is derived from the underlying classical one. It is closely related to the Liouville operator. We demonstrate in several examples the necessity of regularization, in order to arrive at quantum models with bounded spectrum and stable groundstate.
Discrete Lagrangian Systems on Graphs. Symplecto-Topological Properties
S. P. Novikov; A. S. Schwarz
2000-04-11T23:59:59.000Z
Discrete Lagrangian Systems on graphs are considered. Vector-valued closed differential 2-form on the space of solutions is constructed. This form takes values in the first homology group of the graph. This construction generalizes the Symplectic Wronskian for the linear self-adjoint operators on graphs found in 1997 by the first author and used for the needs of the Scattering Theory for graphs with tails
Scaling behavior of discretization errors in renormalization and improvement constants
Bhattacharya, T; Lee, W; Sharpe, S R; Bhattacharya, Tanmoy; Gupta, Rajan; Lee, Weonjong; Sharpe, Stephen R.
2006-01-01T23:59:59.000Z
Non-perturbative results for improvement and renormalization constants needed for on-shell and off-shell O(a) improvement of bilinear operators composed of Wilson fermions are presented. The calculations have been done in the quenched approximation at beta=6.0, 6.2 and 6.4. To quantify residual discretization errors we compare our data with results from other non-perturbative calculations and with one-loop perturbation theory.
Deriving Spin within a discrete-time theory
Erasmo Recami; Giovanni Salesi
2007-01-13T23:59:59.000Z
We prove that the classical theory with a discrete time (chronon) is a particular case of a more general theory in which spinning particles are associated with generalized Lagrangians containing time-derivatives of any order (a theory that has been called "Non-Newtonian Mechanics"). As a consequence, we get, for instance, a classical kinematical derivation of Hamiltonian and spin vector for the mentioned chronon theory (e.g., in Caldirola et al.'s formulation).
THREE-DIMENSIONAL DISCRETE ORDINATES REACTOR ASSEMBLY CALCULATIONS ON GPUS
Evans, Thomas M [ORNL; Joubert, Wayne [ORNL; Hamilton, Steven P [ORNL; Johnson, Seth R [ORNL; Turner, John A [ORNL; Davidson, Gregory G [ORNL; Pandya, Tara M [ORNL
2015-01-01T23:59:59.000Z
In this paper we describe and demonstrate a discrete ordinates sweep algorithm on GPUs. This sweep algorithm is nested within a multilevel comunication-based decomposition based on energy. We demonstrated the effectiveness of this algorithm on detailed three-dimensional critical experiments and PWR lattice problems. For these problems we show improvement factors of 4 6 over conventional communication-based, CPU-only sweeps. These sweep kernel speedups resulted in a factor of 2 total time-to-solution improvement.
Equilibration of an atmosphere by geostrophic turbulence
Jansen, Malte F. (Malte Friedrich)
2013-01-01T23:59:59.000Z
A major question for climate studies is to quantify the role of turbulent eddy fluxes in maintaining the observed atmospheric mean state. It has been argued that eddy fluxes keep the mid-latitude atmosphere in a state that ...
ATMOSPHERIC SCIENCE LETTERS Atmos. Sci. Let. (2012)
Gerber, Edwin
2012-01-01T23:59:59.000Z
ATMOSPHERIC SCIENCE LETTERS Atmos. Sci. Let. (2012) Published online in Wiley Online Library using National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP) concentrations and sea- surface temperatures (SSTs). These integrations enable the relative role of ozone
Land and Atmospheric Science GRAD STUDENT HANDBOOK
Minnesota, University of
Land and Atmospheric Science GRAD STUDENT HANDBOOK 20142015 WELCOME Welcome to the Graduate Program in Land and Atmospheric Science at the University of Minnesota. It is a sciencebased interdisciplinary program focused on the fundamentals of Earth system processes related
Entanglement Generation Using Discrete Solitons in Coulomb Crystals
H. Landa; A. Retzker; T. Schaetz; B. Reznik
2014-07-31T23:59:59.000Z
Laser cooled and trapped ions can crystallize and feature discrete solitons, that are nonlinear, topologically-protected configurations of the Coulomb crystal. Such solitons, as their continuum counterparts, can move within the crystal, while their discreteness leads to the existence of a gap-separated, spatially-localized motional mode of oscillation above the spectrum. Suggesting that these unique properties of discrete solitons can be used for generating entanglement between different sites of the crystal, we study a detailed proposal in the context of state-of-the-art experimental techniques. We analyze the interaction of periodically-driven planar ion crystals with optical forces, revealing the effects of micromotion in radio-frequency traps inherent to such structures, as opposed to linear ion chains. The proposed method requires Doppler cooling of the crystal and sideband cooling of the soliton's localized modes alone. Since the gap separation of the latter is nearly independent of the crystal size, this approach could be particularly useful for producing entanglement and studying system-environment interactions in large, two- and possibly three-dimensional systems.
Heuristic Optimization for the Discrete Virtual Power Plant Dispatch Problem
Petersen, Mette K.; Hansen, Lars H.; Bendtsen, Jan; Edlund, Kristian; Stoustrup, Jakob
2014-10-17T23:59:59.000Z
We consider a virtual power plant, which is given the task of dispatching a fluctuating power supply to a portfolio of flexible consumers. The flexible consumers are modeled as discrete batch processes, and the associated optimization problem is denoted the discrete virtual power plant dispatch problem (DVPPDP). First, the nondeterministic polynomial time (NP)-completeness of the discrete virtual power plant dispatch problem is proved formally. We then proceed to develop tailored versions of the meta-heuristic algorithms hill climber and greedy randomized adaptive search procedure (GRASP). The algorithms are tuned and tested on portfolios of varying sizes. We find that all the tailored algorithms perform satisfactorily in the sense that they are able to find sub-optimal, but usable, solutions to very large problems (on the order of 105 units) at computation times on the scale of just 10 s, which is far beyond the capabilities of the optimal algorithms we have tested. In particular, GRASP sorted shows with the most promising performance, as it is able to find solutions that are both agile (sorted) and well balanced, and consistently yields the best numerical performance among the developed algorithms.
Convergence analysis of the thermal discrete dipole approximation
Edalatpour, Sheila; Trueax, Tyler; Backman, Roger; Francoeur, Mathieu
2015-01-01T23:59:59.000Z
The thermal discrete dipole approximation (T-DDA) is a numerical approach for modeling near-field radiative heat transfer in complex three-dimensional geometries. In this work, the convergence of the T-DDA is investigated using the exact solution for two spheres separated by a vacuum gap. The error associated with the T-DDA is reported for various size parameters, refractive indices and vacuum gap sizes. The results reveal that for a fixed number of sub-volumes, the accuracy of the T-DDA degrades as the refractive index and the sphere diameter to gap ratio increase. A converging trend is observed as the number of sub-volumes increases. The large computational requirements associated with increasing the number of sub-volumes, and the shape error induced by large sphere diameter to gap ratios, are mitigated by using a non-uniform discretization scheme. Non-uniform discretization is shown to significantly accelerate the convergence of the T-DDA, and is thus recommended for near-field thermal radiation simulation...
Lowenstein, Andrew; Miller, Jeffrey; Gruendeman, Peter; DaSilva, Michael
2005-02-01T23:59:59.000Z
An air conditioner comprises a plurality of plates arranged in a successively stacked configuration with portions thereof having a spaced apart arrangement, and defining between successive adjacent pairs of plates at the spaced apart portions a first and second series of discrete alternating passages wherein a first air stream is passed through the first series of passages and a second air stream is passed through the second series of passages; and said stacked configuration of plates forming integrally therewith a liquid delivery means for delivering from a source a sufficient quantity of a liquid to the inside surfaces of the first series of fluid passages in a manner which provides a continuous flow of the liquid from a first end to a second end of the plurality of plates while in contact with the first air stream.
Atmospheric Chemistry and Air Pollution
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gaffney, Jeffrey S.; Marley, Nancy A.
2003-01-01T23:59:59.000Z
Atmospheric chemistry is an important discipline for understanding air pollution and its impacts. This mini-review gives a brief history of air pollution and presents an overview of some of the basic photochemistry involved in the production of ozone and other oxidants in the atmosphere. Urban air quality issues are reviewed with a specific focus on ozone and other oxidants, primary and secondary aerosols, alternative fuels, and the potential for chlorine releases to amplify oxidant chemistry in industrial areas. Regional air pollution issues such as acid rain, long-range transport of aerosols and visibility loss, and the connections of aerosols to ozonemore »and peroxyacetyl nitrate chemistry are examined. Finally, the potential impacts of air pollutants on the global-scale radiative balances of gases and aerosols are discussed briefly.« less
Atmospheric composition change - global and regional air quality
2009-01-01T23:59:59.000Z
in urban air. Atmospheric Chemistry and Physics 5, 2881–deep convective system. Atmospheric Chemistry and Physics 4,processes in atmospheric chemistry. Chemical Society Review
Coupling of nitrous oxide and methane by global atmospheric chemistry
Prather, MJ; Hsu, J
2010-01-01T23:59:59.000Z
supported by NSF’s Atmospheric Chemistry program (grant ATM-Methane by Global Atmospheric Chemistry Michael J. Prathergas, through atmospheric chemistry that en- hances the
Formation mechanisms and quantification of organic nitrates in atmospheric aerosol
Rollins, Andrew Waite
2010-01-01T23:59:59.000Z
and J. Viidanoja, Atmospheric chemistry of c 3 -c 6organic nitrates, Atmospheric Chemistry and Physics, 9 (4),organic aerosol yields, Atmospheric Chemistry and Physics
1997 Atmospheric Chemistry Colloquium for Emerging Senior Scientists
Paul H. Wine
1998-11-23T23:59:59.000Z
DOE's Atmospheric Chemistry Program is providing partial funding for the Atmospheric Chemistry Colloquium for Emerging Senior Scientists (ACCESS) and FY 1997 Gordon Research Conference in Atmospheric Chemistry
Cobos, Douglas Russell
1999-01-01T23:59:59.000Z
Carbon dioxide exchange rate (CER) is an indicator of an ecosystem's response to changing environmental conditions. Long-term measurements of CO? exchange between coastal wetlands and the atmosphere will improve our understanding of daily...
A Recognized Leader in Marine & Atmospheric
Miami, University of
D/Masters Applied Marine Physics Marine & Atmospheric Chemistry Marine Affairs & Policy (Masters Only) MarineA Recognized Leader in Marine & Atmospheric Studies Our graduate program has over 250 students University of MiaMi rosenstiel school of Marine & atMospheric science #12;Miami Ranks #5: fDi Magazine's Top
Atmospheric evolution on Venus Bruce Fegley, Jr.
1 Atmospheric evolution on Venus Bruce Fegley, Jr. Planetary Chemistry Laboratory Department by Hunten et al. (1983), of Magellan results by Bougher et al. (1997), and atmospheric chemistry on Venus and Ancient Environments Edited by Vivien Gornitz January 2004 #12;2 ATMOSPHERIC EVOLUTION ON VENUS Overview
Atmospheric Lifetime of Fossil Fuel Carbon Dioxide
Atmospheric Lifetime of Fossil Fuel Carbon Dioxide David Archer,1 Michael Eby,2 Victor Brovkin,3 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere literature on the atmospheric lifetime of fossil fuel CO2 and its impact on climate, and we present initial
Proof of the Atmospheric Greenhouse Effect
Smith, Arthur P
2008-01-01T23:59:59.000Z
A recently advanced argument against the atmospheric greenhouse effect is refuted. A planet without an infrared absorbing atmosphere is mathematically constrained to have an average temperature less than or equal to the effective radiating temperature. Observed parameters for Earth prove that without infrared absorption by the atmosphere, the average temperature of Earth's surface would be at least 33 K lower than what is observed.
Atmos. Chem. Phys., 3, 469474, 2003 www.atmos-chem-phys.org/acp/3/469/ Atmospheric
Paris-Sud XI, Université de
with -pinene, limonene or catechol and OH radicals with toluene or limonene, respec- tively. The aerosols were sampled on filters and exposed to humidified NO2 mixtures under atmospheric conditions. The estimated
Atmospheric-pressure plasma jet
Selwyn, Gary S. (Los Alamos, NM)
1999-01-01T23:59:59.000Z
Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.
Schellart, P; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P
2015-01-01T23:59:59.000Z
We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields.
Satoshi Ohya; Makoto Sakamoto; Motoi Tachibana
2013-01-28T23:59:59.000Z
In this paper we argue that boundary condition may run with energy scale. As an illustrative example, we consider one-dimensional quantum mechanics for a spinless particle that freely propagates in the bulk yet interacts only at the origin. In this setting we find the renormalization group flow of U(2) family of boundary conditions exactly. We show that the well-known scale-independent subfamily of boundary conditions are realized as fixed points. We also discuss the duality between two distinct boundary conditions from the renormalization group point of view. Generalizations to conformal mechanics and quantum graph are also discussed.
On Estimating Conditional Conservatism
Ball, Ray
The concept of conditional conservatism (asymmetric earnings timeliness) has provided new insight into financial reporting and stimulated considerable research since Basu (1997). Patatoukas and Thomas (2011) report bias ...
Mechanical Performance Extreme Conditions
Mechanical Performance Extreme Conditions METALS This project provides property data, metrology information using the image correlation technique. With this instrument, high strain rate mechanical testing
. Most modern industrial robots are (human) arm-inspired mechanisms with serially arranged discrete rigid
Briefing Document Institute of Space and Atmospheric Studies
Saskatchewan, University of
in Research "Atmospheric Environment" 1 Atmospheric Processes: radiation, chemistry, dynamics "Climate Change1 Briefing Document Institute of Space and Atmospheric Studies A Research Unit within Department;2 Institute of Space and Atmospheric Studies (ISAS) Providing National and International Leadership
Natalie Marie Mahowald Department of Earth and Atmospheric Sciences
Mahowald, Natalie
in the Community Atmosphere Model: development of framework and impact on radiative forcing, Atmospheric Chemistry, Atmospheric Chemistry and 1 1 Natalie Marie Mahowald Department of Earth and Atmospheric Sciences Professor Director
Nanoindentation Under Dynamic Conditions
Wheeler, Jeffrey M
2009-05-22T23:59:59.000Z
of H2 atmosphere P mN Load Q kJ mol-1 Activation energy R J mol-1 K-1 Molar gas constant - 8.31451 ± 7.0e-05 S mN nm-1 Stiffness – dp/dh at peak load and depth T ºC Temperature Tc ºC Critical temperature above which hydrogen has no miscibility... fraction for ? palladium ?H kJ mol-1 Enthalpy of formation ?S0 J K-1 mol-1 Entropy of formation ? - Strain ? Pa Linear work hardening parameter ? º Angle between indenter face and central axis ? - Poisson’s ratio ? i - Poisson’s ratio of indenter ?...
Pulsed atmospheric fluidized bed combustion
Not Available
1993-01-01T23:59:59.000Z
The Design and Engineering of most components in the Pulsed Atmospheric Fluidized Bed System was completed prior to September 1992. The components remaining to be designed at that time were: Aerovalves for the Pulse Combustor; Gas and coal injectors for the Pulse Combustor; Lines for PC tailpipes; Air plenum and inlet silencer; Refractory lined hot gas duct connecting outlet hot cyclone to boiler; Structure and platforms, and ladders around PAFBC vessel access and major equipment. Design work is currently in progress on all of the above components. Items 1, 2, 3 and 4 are 50% completed, and items 5 6 are 75% complete.
Pulse atmospheric fluidized bed combustion
Not Available
1989-03-01T23:59:59.000Z
The overall objective of the program is the development of a pulsed atmospheric fluidized-bed combustion (PAFBC) technology to burn coal and to provide heat and steam to commercial, institutional, and small industrial applications at a reasonable price in an environmentally acceptable manner. During this reporting period, a total of eight shakedown and debugging coal combustion tests were performed in the AFBC. A start-up procedure was established, system improvements implemented, and preliminary material and heat balances made based on these tests. The pulse combustor for the AFBC system was fabricated and installed and a series of tests was conducted on the system. 17 figs., 5 tabs.
Signatures of discrete symmetries in the scalar sector
Lavoura, L. (Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213 (United States))
1994-12-01T23:59:59.000Z
I discuss methods to identify the presence of discrete symmetries in the two-Higgs-doublet model by observing the masses and the cubic and quartic interactions of the scalars. The symmetries considered are a [ital Z][sub 2] symmetry under which [phi][sub 2][r arrow][minus][phi][sub 2], and a [ital CP] symmetry which enforces real coupling constants in the Higgs potential. Those symmetries are spontaneously broken, and the [ital Z][sub 2] symmetry may also be softly broken. I identify the signatures in the interactions of the scalars that these symmetries leave after their breaking.
Distributed mean curvature on a discrete manifold for Regge calculus
Rory Conboye; Warner A. Miller; Shannon Ray
2015-02-26T23:59:59.000Z
The integrated mean curvature of a simplicial manifold is well understood in both Regge Calculus and Discrete Differential Geometry. However, a well motivated pointwise definition of curvature requires a careful choice of volume over which to uniformly distribute the local integrated curvature. We show that hybrid cells formed using both the simplicial lattice and its circumcentric dual emerge as a remarkably natural structure for the distribution of this local integrated curvature. These hybrid cells form a complete tessellation of the simplicial manifold, contain a geometric orthonormal basis, and are also shown to give a pointwise mean curvature with a natural interpretation as a fractional rate of change of the normal vector.
Hu, Jian Zhi (Richland, WA); Sears, Jr., Jesse A. (Kennewick, WA); Hoyt, David W. (Richland, WA); Wind, Robert A. (Kennewick, WA)
2009-05-19T23:59:59.000Z
Described are a "Discrete Magic Angle Turning" (DMAT) system, devices, and processes that combine advantages of both magic angle turning (MAT) and magic angle hopping (MAH) suitable, e.g., for in situ magnetic resonance spectroscopy and/or imaging. In an exemplary system, device, and process, samples are rotated in a clockwise direction followed by an anticlockwise direction of exactly the same amount. Rotation proceeds through an angle that is typically greater than about 240 degrees but less than or equal to about 360 degrees at constant speed for a time applicable to the evolution dimension. Back and forth rotation can be synchronized and repeated with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. The design permits tubes to be inserted into the sample container without introducing plumbing interferences, further allowing control over such conditions as temperature, pressure, flow conditions, and feed compositions, thus permitting true in-situ investigations to be carried out.
01/14 Ver. 4.1 Atmospheric,OceanicandSpaceSciences
Eustice, Ryan
Areas Atmosphere Biosphere Interactions Atmospheric Chemistry, Aerosols & Air Quality Atmospheric01/14 Ver. 4.1 Atmospheric,OceanicandSpaceSciences Research areas Atmospheric Science Research Atmospheric & Space Science Research Areas Numerical Methods & Scientific Computing Planetary Atmospheres
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Huang, Lei; Zuo, Chao; Idir, Mourad; Qu, Weijuan; Asundi, Anand
2015-01-01T23:59:59.000Z
A novel transport-of-intensity equation (TIE) based phase retrieval method is proposed with putting an arbitrarily-shaped aperture into the optical wavefield. In this arbitrarily-shaped aperture, the TIE can be solved under non-uniform illuminations and even non-homogeneous boundary conditions by iterative discrete cosine transforms with a phase compensation mechanism. Simulation with arbitrary phase, arbitrary aperture shape, and non-uniform intensity distribution verifies the effective compensation and high accuracy of the proposed method. Experiment is also carried out to check the feasibility of the proposed method in real measurement. Comparing to the existing methods, the proposed method is applicable for any types of phasemore »distribution under non-uniform illumination and non-homogeneous boundary conditions within an arbitrarily-shaped aperture, which enables the technique of TIE with hard aperture become a more flexible phase retrieval tool in practical measurements.« less
Conditioning analysis of incomplete Cholesky factorizations with orthogonal dropping
Napov, Artem
2012-03-16T23:59:59.000Z
The analysis of preconditioners based on incomplete Cholesky factorization in which the neglected (dropped) components are orthogonal to the approximations being kept is presented. General estimate for the condition number of the preconditioned system is given which only depends on the accuracy of individual approximations. The estimate is further improved if, for instance, only the newly computed rows of the factor are modified during each approximation step. In this latter case it is further shown to be sharp. The analysis is illustrated with some existing factorizations in the context of discretized elliptic partial differential equations.
Conditional data watchpoint management
Burdick, Dean Joseph (Austin, TX); Vaidyanathan, Basu (Austin, TX)
2010-08-24T23:59:59.000Z
A method, system and computer program product for managing a conditional data watchpoint in a set of instructions being traced is shown in accordance with illustrative embodiments. In one particular embodiment, the method comprises initializing a conditional data watchpoint and determining the watchpoint has been encountered. Upon that determination, examining a current instruction context associated with the encountered watchpoint prior to completion of the current instruction execution, further determining a first action responsive to a positive context examination; otherwise, determining a second action.
Discrete-element modeling of particulate aerosol flows
Marshall, J.S. [School of Engineering, University of Vermont, 33 Colchecter Avenue, Burlington, Vermont 05405 (United States)], E-mail: jeffm@cems.uvm.edu
2009-03-20T23:59:59.000Z
A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including smoke particle transport in the lungs, particle clogging of heat exchangers in construction vehicles, industrial nanoparticle transport and filtration systems, and dust fouling of electronic systems and MEMS components. Dust fouling of equipment is of particular concern for potential human occupation on dusty planets, such as Mars. The discrete-element method presented in this paper can be used for prediction of aggregate structure and breakup, for prediction of the effect of aggregate formation on the bulk fluid flow, and for prediction of the effects of small-scale flow features (e.g., due to surface roughness or MEMS patterning) on the aggregate formation. After presentation of the overall computational structure, the forces and torques acting on the particles resulting from fluid motion, particle-particle collision, and adhesion under van der Waals forces are reviewed. The effect of various parameters of normal collision and adhesion of two particles are examined in detail. The method is then used to examine aggregate formation and particle clogging in pipe and channel flow.
Dual hidden landscapes in Anderson localization on discrete lattices
Marcelo Leite Lyra; Svitlana Mayboroda; Marcel Filoche
2014-10-09T23:59:59.000Z
The localization subregions of stationary waves in continuous disordered media have been recently demonstrated to be governed by a hidden landscape that is the solution of a Dirichlet problem expressed with the wave operator. In this theory, the strength of Anderson localization confinement is determined by this landscape, and continuously decreases as the energy increases. However, this picture has to be changed in discrete lattices in which the eigenmodes close to the edge of the first Brillouin zone are as localized as the low energy ones. Here we show that in a 1D discrete lattice, the localization of low and high energy modes is governed by two different landscapes, the high energy landscape being the solution of a dual Dirichlet problem deduced from the low energy one using the symmetries of the Hamiltonian. We illustrate this feature using the one-dimensional tight-binding Hamiltonian with random on-site potentials as a prototype model. Moreover we show that, besides unveiling the subregions of Anderson localization, these dual landscapes also provide an accurate overal estimate of the localization length over the energy spectrum, especially in the weak disorder regime.
Discrete transforms and orthogonal polynomials of (anti)symmetric multivariate cosine functions
Ji?í Hrivnák; Lenka Motlochová
2014-11-27T23:59:59.000Z
The discrete cosine transforms of types V--VIII are generalized to the antisymmetric and symmetric multivariate discrete cosine transforms. Four families of discretely and continuously orthogonal Chebyshev-like polynomials corresponding to the antisymmetric and symmetric generalizations of cosine functions are introduced. Each family forms an orthogonal basis of the space of all polynomials with respect to some weighted integral. Cubature formulas, which correspond to these families of polynomials and which stem from the developed discrete cosine transforms, are derived. Examples of three-dimensional interpolation formulas and three-dimensional explicit forms of the polynomials are presented.
Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle are derived either at microscale with random distribution of material properties or at a mesoscale
Atmospheric neutrino flux at INO site
Honda, Morihiro [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8582 (Japan)
2011-11-23T23:59:59.000Z
To illustrate the calculation of the atmospheric neutrino flux, we briefly explain our calculation scheme and important components, such as primary cosmic ray spectra, interaction model, and geomagnetic model. Then, we calculate the atmospheric neutrino flux at INO site in our calculation scheme. We compare the calculated atmospheric neutrino fluxes predicted at INO with those at other major neutrino detector sites, especially that at SK site.
Super-Kamiokande atmospheric neutrino results
Toshiyuki Toshito; the Super-Kamiokande collaboration
2001-05-14T23:59:59.000Z
We present atmospheric neutrino results from a 79 kiloton year (1289 days) exposure of the Super-Kamiokande detector. Our data are well explained by $\
Impacts of Atmospheric Anthropogenic Nitrogen on the
Ward, Bess
discharges from wastewater treatment, atmospheric deposition, and so forth, resulting in increasing), including oxidized and reduced inorganic and organic forms. The availability of Nr limits primary pro
Toxicity of atmospheric aerosols on marine phytoplankton
2009-01-01T23:59:59.000Z
metals added from these aerosols to the bioassay incubationsreleased to seawater from the aerosol filters after Author4605 CHEMISTRY Atmospheric aerosol deposition CHEMISTRY
4, 497545, 2011 atmosphere-wildland
Mandel, Jan
by the coupling of a mesoscale weather 498 #12;GMDD 4, 497545, 2011 Coupled atmosphere-wildland model WRF-Fire 3
Physics Potential of Future Atmospheric Neutrino Searches
Thomas Schwetz
2008-12-12T23:59:59.000Z
The potential of future high statistics atmospheric neutrino experiments is considered, having in mind currently discussed huge detectors of various technologies (water Cerekov, magnetized iron, liquid Argon). I focus on the possibility to use atmospheric data to determine the octant of $\\theta_{23}$ and the neutrino mass hierarchy. The sensitivity to the $\\theta_{23}$-octant of atmospheric neutrinos is competitive (or even superior) to long-baseline experiments. I discuss the ideal properties of a fictitious atmospheric neutrino detector to determine the neutrino mass hierarchy.
Characterizing orbit uncertainty due to atmospheric uncertainty
Wilkins, Matthew Paul
2000-01-01T23:59:59.000Z
is implemented to model errors in the atmospheric density model. This study shows that the Kalman filter computes a believable and more realistic covariance....
Mesoscale coupled ocean-atmosphere interaction
Seo, Hyodae
2007-01-01T23:59:59.000Z
mesoscale oceanic features are current coarse resolutionmesoscale r current variability associated with oceanic ringthe TIW- currents. These mesoscale oceanic and atmospheric
Mesoscale Coupled Ocean-Atmosphere Interaction
Seo, Hyodae
2007-01-01T23:59:59.000Z
mesoscale oceanic features are current coarse resolutionmesoscale r current variability associated with oceanic ringthe TIW- currents. These mesoscale oceanic and atmospheric
Atmospheric chemistry of an Antarctic volcanic plume
2010-01-01T23:59:59.000Z
ET AL. : EREBUS PLUME CHEMISTRY Horrocks, L. A. , C.et al. (2010), Atmospheric chemistry results from the ANTCI2007), Reactive halogen chemistry in volca- nic plumes, J.
Pulsed atmospheric fluidized bed combustion
Not Available
1992-10-01T23:59:59.000Z
The design of the Pulsed Atmospheric Fluidized Bed Combustor (PAFBC) as described in the Quarterly Report for the period April--June, 1992 was reviewed and minor modifications were included. The most important change made was in the coal/limestone preparation and feed system. Instead of procuring pre-sized coal for testing of the PAFBC, it was decided that the installation of a milling system would permit greater flexibility in the testing with respect to size distributions and combustion characteristics in the pulse combustor and the fluid bed. Particle size separation for pulse combustor and fluid bed will be performed by an air classifier. The modified process flow diagram for the coal/limestone handling system is presented in Figure 1. The modified process flow diagrams of the fluidized bed/steam cycle and ash handling systems are presented in Figures 2 and 3, respectively.
NDE to Manage Atmospheric SCC in Canisters for Dry Storage of Spent Fuel: An Assessment
Meyer, Ryan M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pardini, Allan F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cuta, Judith M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adkins, Harold E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Casella, Andrew M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qiao, Hong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Larche, Michael R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diaz, Aaron A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Doctor, Steven R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2013-09-01T23:59:59.000Z
This report documents efforts to assess representative horizontal (Transuclear NUHOMS®) and vertical (Holtec HI-STORM) storage systems for the implementation of non-destructive examination (NDE) methods or techniques to manage atmospheric stress corrosion cracking (SCC) in canisters for dry storage of used nuclear fuel. The assessment is conducted by assessing accessibility and deployment, environmental compatibility, and applicability of NDE methods. A recommendation of this assessment is to focus on bulk ultrasonic and eddy current techniques for direct canister monitoring of atmospheric SCC. This assessment also highlights canister regions that may be most vulnerable to atmospheric SCC to guide the use of bulk ultrasonic and eddy current examinations. An assessment of accessibility also identifies canister regions that are easiest and more difficult to access through the ventilation paths of the concrete shielding modules. A conceivable sampling strategy for canister inspections is to sample only the easiest to access portions of vulnerable regions. There are aspects to performing an NDE inspection of dry canister storage system (DCSS) canisters for atmospheric SCC that have not been addressed in previous performance studies. These aspects provide the basis for recommendations of future efforts to determine the capability and performance of eddy current and bulk ultrasonic examinations for atmospheric SCC in DCSS canisters. Finally, other important areas of investigation are identified including the development of instrumented surveillance specimens to identify when conditions are conducive for atmospheric SCC, characterization of atmospheric SCC morphology, and an assessment of air flow patterns over canister surfaces and their influence on chloride deposition.
Fish Passage though Hydropower Turbines: Simulating Blade Strike using the Discrete Element Method
Richmond, Marshall C.; Romero Gomez, Pedro DJ
2014-12-08T23:59:59.000Z
mong the hazardous hydraulic conditions affecting anadromous and resident fish during their passage though turbine flows, two are believed to cause considerable injury and mortality: collision on moving blades and decompression. Several methods are currently available to evaluate these stressors in installed turbines, i.e. using live fish or autonomous sensor devices, and in reduced-scale physical models, i.e. registering collisions from plastic beads. However, a priori estimates with computational modeling approaches applied early in the process of turbine design can facilitate the development of fish-friendly turbines. In the present study, we evaluated the frequency of blade strike and nadir pressure environment by modeling potential fish trajectories with the Discrete Element Method (DEM) applied to fish-like composite particles. In the DEM approach, particles are subjected to realistic hydraulic conditions simulated with computational fluid dynamics (CFD), and particle-structure interactions—representing fish collisions with turbine blades—are explicitly recorded and accounted for in the calculation of particle trajectories. We conducted transient CFD simulations by setting the runner in motion and allowing for better turbulence resolution, a modeling improvement over the conventional practice of simulating the system in steady state which was also done here. While both schemes yielded comparable bulk hydraulic performance, transient conditions exhibited a visual improvement in describing flow variability. We released streamtraces (steady flow solution) and DEM particles (transient solution) at the same location from where sensor fish (SF) have been released in field studies of the modeled turbine unit. The streamtrace-based results showed a better agreement with SF data than the DEM-based nadir pressures did because the former accounted for the turbulent dispersion at the intake but the latter did not. However, the DEM-based strike frequency is more representative of blade-strike probability than the steady solution is, mainly because DEM particles accounted for the full fish length, thus resolving (instead of modeling) the collision event.
Zhuang, Qianlai
Soil consumption of atmospheric methane plays an important secondary role in regulating the atmospheric CH4 budget, next to the dominant loss mechanism involving reaction with the hydroxyl radical (OH). Here we used a ...
A Convective-like Energy-Stable Open Boundary Condition for Simulations of Incompressible Flows
Dong, Suchuan
2015-01-01T23:59:59.000Z
We present a new energy-stable open boundary condition, and an associated numerical algorithm, for simulating incompressible flows with outflow/open boundaries. This open boundary condition ensures the energy stability of the system, even when strong vortices or backflows occur at the outflow boundary. Under certain situations it can be reduced to a form that can be analogized to the usual convective boundary condition. One prominent feature of this boundary condition is that it provides a control over the velocity on the outflow/open boundary. This is not available with the other energy-stable open boundary conditions from previous works. Our numerical algorithm treats the proposed open boundary condition based on a rotational velocity-correction type strategy. It gives rise to a Robin-type condition for the discrete pressure and a Robin-type condition for the discrete velocity on the outflow/open boundary, respectively at the pressure and the velocity sub-steps. We present extensive numerical experiments on...
Atmospheric neutrino flux calculation using the NRLMSISE00 atmospheric model
Honda, M; Kajita, T; Kasahara, K; Midorikawa, S
2015-01-01T23:59:59.000Z
In this paper, we extend the calculation of the atmospheric neutrino flux~\\cite{hkkm2004,hkkms2006,hkkm2011} to the sites in polar and tropical regions. In our earliest full 3D-calculation~\\cite{hkkm2004}, we used DPMJET-III~\\cite{dpm} for the hadronic interaction model above 5~GeV, and NUCRIN~\\cite{nucrin} below 5~GeV. We modified DPMJET-III as in Ref.~\\cite{hkkms2006} to reproduce the experimental muon spectra better, mainly using the data observed by BESS group~\\cite{BESSTeVpHemu}. In a recent work~\\cite{hkkm2011}, we introduced JAM interaction model for the low energy hadronic interactions. JAM is a nuclear interaction model developed with PHITS (Particle and Heavy-Ion Transport code System)~\\cite{phits}. In Ref.~\\cite{hkkm2011}, we could reproduce the observed muon flux at the low energies at balloon altitude with DPMJET-III above 32 GeV and JAM below that better than the combination of DPMJET-III above 5~GeV and NUCRIN below that. Besides the interaction model, we have also improved the calculation sche...
2300 SYSTEM Conditioning Amplifier
Gellman, Andrew J.
2300 SYSTEM Signal Conditioning Amplifier 2310 Instruction Manual Vishay Micro-Measurements P date of shipment. Coverage of computers, cameras, rechargeable batteries, and similar items, sold on non-rechargeable batteries and similar consumable items is limited to the delivery of goods free from
Broader source: Energy.gov [DOE]
We take it for granted but what would life be like without the air conditioner? Once considered a luxury, this invention is now an essential, allowing us to cool everything from homes, businesses, businesses, data centers, laboratories and other buildings vital to our daily lives. Explore this timeline to learn some of the key dates in the history of air conditioning.
Semiclassical approach to discrete symmetries in quantum chaos
Joyner, Chris; Sieber, Martin
2012-01-01T23:59:59.000Z
We use semiclassical methods to evaluate the spectral two-point correlation function of quantum chaotic systems with discrete geometrical symmetries. The energy spectra of these systems can be divided into subspectra that are associated to irreducible representations of the corresponding symmetry group. We show that for (spinless) time reversal invariant systems the statistics inside these subspectra depend on the type of irreducible representation. For real representations the spectral statistics agree with those of the Gaussian Orthogonal Ensemble (GOE) of Random Matrix Theory (RMT), whereas complex representations correspond to the Gaussian Unitary Ensemble (GUE). For systems without time reversal invariance all subspectra show GUE statistics. There are no correlations between non-degenerate subspectra. Our techniques generalize recent developments in the semiclassical approach to quantum chaos allowing one to obtain full agreement with the two-point correlation function predicted by RMT, including oscilla...
Semiclassical approach to discrete symmetries in quantum chaos
Chris Joyner; Sebastian Müller; Martin Sieber
2012-02-22T23:59:59.000Z
We use semiclassical methods to evaluate the spectral two-point correlation function of quantum chaotic systems with discrete geometrical symmetries. The energy spectra of these systems can be divided into subspectra that are associated to irreducible representations of the corresponding symmetry group. We show that for (spinless) time reversal invariant systems the statistics inside these subspectra depend on the type of irreducible representation. For real representations the spectral statistics agree with those of the Gaussian Orthogonal Ensemble (GOE) of Random Matrix Theory (RMT), whereas complex representations correspond to the Gaussian Unitary Ensemble (GUE). For systems without time reversal invariance all subspectra show GUE statistics. There are no correlations between non-degenerate subspectra. Our techniques generalize recent developments in the semiclassical approach to quantum chaos allowing one to obtain full agreement with the two-point correlation function predicted by RMT, including oscillatory contributions.
Multipole-preserving quadratures for discretization of functions
Genovese, Luigi
2015-01-01T23:59:59.000Z
Discretizing an analytic function on a uniform real-space grid is often done via a straightforward collocation method. This is ubiquitous in all areas of computational physics and quantum chemistry. An example in Density Functional Theory is given by the local external potential describing the interaction between ions and electrons. Also notable examples are given by the analytic functions defining compensation charges for range-separated electrostatic treatments. The accuracy of the collocation method used is therefore very important for the reliability of subsequent treatments like self-consistent field solutions of the electronic structure problems. When the real-space grid is too coarse, the collocation method introduces numerical artifacts typical of real-space treatments, like the so-called egg-box error, that may spoil the numerical stability of the description. We present in this paper a new quadrature scheme that is able to exactly preserve the multipoles of a given analytic function for a wide range...
A three-level BDDC algorithm for mortar discretizations
Kim, Hyea Hyun; Tu, Xuemin
2009-03-05T23:59:59.000Z
Society for Industrial and Applied Mathematics Vol. 47, No. 2, pp. 1576–1600 A THREE-LEVEL BDDC ALGORITHM FOR MORTAR DISCRETIZATIONS? HYEA HYUN KIM† AND XUEMIN TU‡ Abstract. In this paper, a three-level balancing domain decomposition by constraints (BDDC...- search, U.S. Department of Energy under contract DE-AC02-05CH11231. 1576 D ow nl oa de d 09 /2 9/ 14 to 1 29 .2 37 .4 6. 10 0. R ed ist rib ut io n su bje ct to SIA M lic en se or co py rig ht; se e h ttp ://w ww .si am .or g/j ou rna ls/ ojs a...
Breaking discrete symmetries in the effective field theory of inflation
Dario Cannone; Jinn-Ouk Gong; Gianmassimo Tasinato
2015-05-29T23:59:59.000Z
We study the phenomenon of discrete symmetry breaking during the inflationary epoch, using a model-independent approach based on the effective field theory of inflation. We work in a context where both time reparameterization symmetry and spatial diffeomorphism invariance can be broken during inflation. We determine the leading derivative operators in the quadratic action for fluctuations that break parity and time-reversal. Within suitable approximations, we study their consequences for the dynamics of linearized fluctuations. Both in the scalar and tensor sectors, we show that such operators can lead to new direction-dependent phases for the modes involved. They do not affect the power spectra, but can have consequences for higher correlation functions. Moreover, a small quadrupole contribution to the sound speed can be generated.
Quantum Discrete Fourier Transform with Classical Output for Signal Processing
Chao-Yang Pang; Ben-Qiong Hu
2007-06-17T23:59:59.000Z
Discrete Fourier transform (DFT) is the base of modern signal or information processing. 1-Dimensional fast Fourier transform (1D FFT) and 2D FFT have time complexity O(NlogN) and O(N^2logN) respectively. Quantum 1D and 2D DFT algorithms with classical output (1D QDFT and 2D QDFT) are presented in this paper. And quantum algorithm for convolution estimation is also presented in this paper. Compared with FFT, QDFT has two advantages at least. One of advantages is that 1D and 2D QDFT has time complexity O(sqrt(N)) and O(N) respectively. The other advantage is that QDFT can process very long signal sequence at a time. QDFT and quantum convolution demonstrate that quantum signal processing with classical output is possible.
Sampling Theorem and Discrete Fourier Transform on the Riemann Sphere
Manuel Calixto; Julio Guerrero; Juan Carlos Sánchez-Monreal
2011-09-09T23:59:59.000Z
Using coherent-state techniques, we prove a sampling theorem for Majorana's (holomorphic) functions on the Riemann sphere and we provide an exact reconstruction formula as a convolution product of $N$ samples and a given reconstruction kernel (a sinc-type function). We also discuss the effect of over- and under-sampling. Sample points are roots of unity, a fact which allows explicit inversion formulas for resolution and overlapping kernel operators through the theory of Circulant Matrices and Rectangular Fourier Matrices. The case of band-limited functions on the Riemann sphere, with spins up to $J$, is also considered. The connection with the standard Euler angle picture, in terms of spherical harmonics, is established through a discrete Bargmann transform.
ATMOSPHERIC SCIENCE LETTERS Atmos. Sci. Let. (2013)
Lee, Sukyoung
2013-01-01T23:59:59.000Z
ATMOSPHERIC SCIENCE LETTERS Atmos. Sci. Let. (2013) Published online in Wiley Online Library Sciences, Seoul National University, Seoul, South Korea *Correspondence to: C. Yoo, Center for Atmosphere). A number of studies have shown that the MJO plays an important role in modulating the extratropical cir
ATOMIC IONIZATION AND OPACITIES IN PULSAR ATMOSPHERES
ATOMIC IONIZATION AND OPACITIES IN PULSAR ATMOSPHERES Hydrogen Atmospheres J. VENTURA Physics.g. Pavlov et al., 1995; Zavlin et al., 1995, 1996; #12; 2 J. VENTURA ET AL. Rajagopal and Romani, 1996 the past three years. As is well known (Canuto and Ventura, 1977; Ruder et al., 1994), the external strong
Human effects on the global atmosphere
Johnston, H.S.
1984-01-01T23:59:59.000Z
This review considers whether human activities can significantly change important functions of the global atmosphere by altering the amount or distribution of certain trace species. It deals with three specific topics: stratopheric ozone, the role of species other than carbon dioxide on the greenhouse effect, and certain recently recognized atmospheric consequences of a large scale nuclear war. 64 references, 10 figures, 2 tables.
National Oceanic & Atmospheric Administration Emergency Notification System
in that region: A tsunami warning has been issued for the greater Pacific basin. All employees should moveNational Oceanic & Atmospheric Administration Emergency Notification System The National Oceanic & Atmospheric Administration (NOAA) Emergency Notification System (ENS) is a tool that allows NOAA to quickly
INVESTIGATING THERMODYNAMICS OF VERTICAL ATMOSPHERIC ENERGY TRANSPORT
INVESTIGATING THERMODYNAMICS OF VERTICAL ATMOSPHERIC ENERGY TRANSPORT Wei Wu and Yangang Liu transport are investigated by using simple one-dimensional vertical energy balance models (i.e., radiative processes (i.e., one of the key processes for vertical atmospheric energy transport) on shaping the Earth
Recursive Total Least Squares: An Alternative to the Discrete Kalman Filter
Boley, Daniel
Recursive Total Least Squares: An Alternative to the Discrete Kalman Filter Daniel L. Boley The discrete Kalman lter, which is becoming a common tool for reducing uncertainty in robot navigation, su ers total least squares estimator (RTLS) as an alternative to the Kalman lter, and compare
Various ways to compute the continuous-discrete Extended Kalman Filter
Paris-Sud XI, Université de
1 Various ways to compute the continuous-discrete Extended Kalman Filter Paul Frogerais, Jean-Jacques Bellanger and Lotfi Senhadji Abstract--The Extended Kalman Filter (EKF) is a very popular tool dealing is guaranteed. Index Terms--Extended Kalman filters, Continuous- discrete filters, Runge-Kutta method, nonlinear
Recursive Total Least Squares: An Alternative to Using the Discrete Kalman
Boley, Daniel
Recursive Total Least Squares: An Alternative to Using the Discrete Kalman Filter in Robot to ob- tain the best estimate of the robot position. The discrete Kalman filter, com- monly used the Kalman filter. To this end, we propose the use of a Recursive Total Least Squares Filter. This filter
To appear in Journal of Computational Physics Parallel Discrete Molecular Dynamics Simulation
Herbordt, Martin
To appear in Journal of Computational Physics Parallel Discrete Molecular Dynamics Simulation and Automated Design Laboratory Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 www.bu.edu/caadlab; email: azkhan@bu.edu, herbordt@bu.edu Abstract: Discrete molecular dynamics
Improving behavioral realism in hybrid energy-economy models using discrete choice
Improving behavioral realism in hybrid energy-economy models using discrete choice studies Abstract Hybrid energy-economy models combine top-down and bottom-up approaches to explore behaviorally models to inform key behavioral parameters in CIMS, a hybrid model. The discrete choice models
Lightweight Floating-Point Arithmetic: Case Study of Inverse Discrete Cosine Transform
Chen, Tsuhan
, customizable bit- width, rounding modes, low-power, inverse discrete cosine transform, video coding 1 of effort must be spent to manage the complexity, power consumption and time-to-market of the modernLightweight Floating-Point Arithmetic: Case Study of Inverse Discrete Cosine Transform Fang Fang
Journal of Discrete Algorithms 4 (2006) 499510 www.elsevier.com/locate/jda
Dimitrios, Thilikos
2006-01-01T23:59:59.000Z
Journal of Discrete Algorithms 4 (2006) 499510 www.elsevier.com/locate/jda A 3-approximation reserved. doi:10.1016/j.jda.2005.06.004 #12;500 F.V. Fomin, D.M. Thilikos / Journal of Discrete Algorithms
Completeness in DiscreteTime Process Algebra Michel A. Reniers and Jan Joris Vereijken
Reniers, Michel
Completeness in DiscreteÂTime Process Algebra Michel A. Reniers and Jan Joris Vereijken Department, 1996 Abstract We prove soundness and completeness for some ACPÂstyle concrete, relativeÂtime, discrete . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Soundness and Completeness . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Basic
Optimal Supervisory Control of Discrete Event Dynamical Systems 1,2
Kumar, Ratnesh
Optimal Supervisory Control of Discrete Event Dynamical Systems 1,2 Ratnesh Kumar Department;Abstract We formalize the notion of optimal supervisory control of discrete event dynamical sys- tems (DEDS some undesired states, or not reaching some desired states in the controlled system. The control
On Optimal Control of a Class of Partially-Observed Discrete Event Systems
Paris-Sud XI, Université de
On Optimal Control of a Class of Partially-Observed Discrete Event Systems H e rv M a rch a n d theC-observer. Thissubmachineleadstothedesiredsupervisorforthesystem. Keywords: DiscreteEventSystems,SupervisoryControlProblem,Optimality(not) be reached in the controlled system, the Optimal Control under Par- tial Observation problem is solved
PERFORMANCE VERIFICATION OF DISCRETE EVENT SYSTEMS USING HYBRID MODEL-CHECKING
Boyer, Edmond
of the plant with a timed discrete model of the controller. We will also show, using a basic examplePERFORMANCE VERIFICATION OF DISCRETE EVENT SYSTEMS USING HYBRID MODEL-CHECKING Bruno Denis (1 Systems (DES) and Hybrid Dynamic Systems (HDS) are quite substantial, especially as regards the controller
Computational Issues in Intelligent Control: Discrete-Event and Hybrid Systems
Koutsoukos, Xenofon D.
Computational Issues in Intelligent Control: Discrete-Event and Hybrid Systems Xenofon D discrete event and hybrid systems. Computational issues of various problems and al- gorithms concerning to address the control needs of complex systems that exhibit complicated dynamical behaviors. The design
Propagation failure in the discrete Nagumo equation H. J. Hupkes a,, D. Pelinovsky b
Hupkes, Hermen Jan
Propagation failure in the discrete Nagumo equation H. J. Hupkes a,, D. Pelinovsky b , B. Sandstede Email: hjhupkes@dam.brown.edu b Department of Mathematics - McMaster University Hamilton, ON L8S 4K1 problem of propagation failure for monotonic fronts of the discrete Nagumo equation. For a special class
Call for Submissions -CanaDAM 2007 Canadian Discrete and Algorithmic Mathematics Conference 2007
Mohar, Bojan
Call for Submissions - CanaDAM 2007 Canadian Discrete and Algorithmic Mathematics Conference 2007 Banff Conference Center, Banff, Alberta, May 28-31, 2007 http://www.cs.ualberta.ca/mreza/CANADAM/ This is a new conference series on Discrete and Algorithmic Mathematics to be held in Canada every two years (in
Europhysics Letters PREPRINT Exploring the lower part of discrete polymer model energy
Stadler, Peter F.
Europhysics Letters PREPRINT Exploring the lower part of discrete polymer model energy landscapes a generic, problem independent algorithm for exploration of the low- energy portion of the energy landscape of discrete systems and apply it to the energy landscape of lattice proteins. Starting from a set of optimal
Bontempi, Gianluca
Lazy learning indirect control for discrete-time non-linear systems Gianluca Bontempi, Mauro propose a hybrid architecture for the indirect control of non linear discrete time plants from of the resulting controller in a simplified case. Experimental results in the control of some non linear benchmarks
Offset-free control of constrained linear discrete-time systems subject to persistent
Cambridge, University of
Offset-free control of constrained linear discrete-time systems subject to persistent unmeasured-free control of constrained linear discrete-time systems subject to persistent unmeasured disturbances Gabriele Technical report CUED/F-INFENG/TR.466 September 10, 2003 #12;#12;Offset-free control of constrained linear
Herbert, John
Symmetric versus asymmetric discretization of the integral equations in polarizable continuum form 28 April 2011 Available online 1 May 2011 a b s t r a c t Discretization of the integral equations of the integral operators. Consequently, the appropriate form of the finite-dimensional matrix equations
Beylkin, Gregory
Discrete Radon Transform GREGORY BEYLKIN Abstract-This paper describes the discrete Radon transform (DRT showthattheDRTcan beused tocomputevariousgen- eralizations of the classical Radon transform (RT) and. An interesting observation is that the exact inversion algorithm cannot be obtained directly from Radon
Discrete-time Lyapunov based small-gain theorem for parameterized interconnected ISS systems
Nesic, Dragan
Discrete-time Lyapunov based small-gain theorem for parameterized interconnected ISS systems Dina via the Lyapunov method. In particular, an ISS Lyapunov function for the overall system is constructed from the ISS Lyapunov functions of the two subsystems. We consider parameterized families of discrete
Friction dependence of shallow granular flows from discrete par-ticle simulations
Al Hanbali, Ahmad
Friction dependence of shallow granular flows from discrete par- ticle simulations Anthony Thornton relation for the macroscopic bed friction or basal roughness obtained from micro-scale discrete particle simulations of steady flows. We systematically vary the bed friction by changing the contact friction
Discrete-Time Model of an IPMSM Based on Variational Integrators
Noé, Reinhold
implemented on a digital platform, a discrete-time motor model is needed. With respect to the calculation space e.g. in the automotive industry. Hence, the IPMSM is often used as a traction drive in today of the art to realize motor control and motor related functions on a digital platform. Thus, discrete- time
MAP-Inference on Large Scale Higher-Order Discrete Graphical Models by Fusion Moves
Schnörr, Christoph
MAP-Inference on Large Scale Higher-Order Discrete Graphical Models by Fusion Moves J¨org Hendrik reconsider the work of Lempitsky et al. 2010 on fusion moves and apply it to general discrete graphical models. We propose two alternatives for calculating fusion moves that outperform the standard in several
WAVELET FRAMES ON GROUPS AND HYPERGROUPS VIA DISCRETIZATION OF CALDERON FORMULAS
Maggioni, Mauro
WAVELET FRAMES ON GROUPS AND HYPERGROUPS VIA DISCRETIZATION OF CALDERÂ´ON FORMULAS MAURO MAGGIONI Abstract. Continuous wavelets are often studied in the general framework of representation theory of square whether these continuous wavelets can be discretized to yield wavelet frames. In this paper we us Calder
The Discrete Wavelet Transform in S G. P. Nason \\Lambda and B. W. Silverman y
Nason, Guy
The Discrete Wavelet Transform in S G. P. Nason \\Lambda and B. W. Silverman y Journal of Computational and Graphical Statistics (1994) 3 163--191 Abstract The theory of wavelets has recently undergone the statistical language S to perform oneÂ and twoÂdimensional discrete wavelet transforms. The transforms
The Discrete Wavelet Transform in S G. P. Nason and B. W. Silvermany
Nason, Guy
The Discrete Wavelet Transform in S G. P. Nason and B. W. Silvermany Journal of Computational and Graphical Statistics 1994 3 163 191 Abstract The theory of wavelets has recently undergone a period of rapid language S to perform one- and two-dimensional discrete wavelet transforms. The transforms
Mechanism Design on Discrete Structures Elad Dokow Michal Feldman Reshef Meir
Fiat, Amos
Mechanism Design on Discrete Structures Elad Dokow Michal Feldman Reshef Meir Ilan Nehama Bar-Ilan University Hebrew University of Jerusalem August 7, 2011 Abstract We study strategyproof (SP) mechanisms for the location of a facility on a discrete graph. We give a full characterization of SP mechanisms on lines
Passive Millimeter-Wave Ranging Using Discrete Lenses with Wave-Front Coding
Popovic, Zoya
of a receiving discrete lens with modulated amplitude and/or phase response. The result is a set of image pat on a relatively small (100-element) discrete lens antenna array with a cosinusoidal amplitude mask and half curve around 94 GHz. Waves in this fre- quency range penetrate through dust, fog and smoke
Wakefield acceleration in atmospheric plasmas: a possible source of MeV electrons
Arrayás, M; Seviour, R; Trueba, J L
2015-01-01T23:59:59.000Z
Intense electromagnetic pulses interacting with a plasma can create a wake of plasma oscillations. Electrons trapped in such oscillations can be accelerated under certain conditions to very high energies. We study the conditions for the wakefield acceleration to produce MeV electrons in atmospheric plasmas. This mechanism may explain the origin of MeV or runaway electrons needed in the current theories for the production of Terrestrial Gamma ray Flashes.
Radiative Transfer in the Midwave Infrared Applicable to Full Spectrum Atmospheric
Kerekes, John
of the radiative effects in the MWIR is needed. The MWIR is characterized by a unique combination of reduced solar conditions are stressing (e.g., high moisture, heavy aerosol/particulate loading, partial cloud cover, lowRadiative Transfer in the Midwave Infrared Applicable to Full Spectrum Atmospheric Characterization
2007-01-01T23:59:59.000Z
Atmospheric Environment 41 (2007) 18031818 Estimating the effects of increased urbanization School of Architecture, Planning & Preservation, Columbia University, NY, USA f Department of Geography this region from ``present-day'' (ca. 1990) conditions to a future year (ca. 2050), and these projections were
Physics 137, Section 1, Winter Semester Introduction to the Atmosphere and Weather
Hart, Gus
Physics 137, Section 1, Winter Semester Introduction to the Atmosphere and Weather OBSERVATIONAL observational project or present one TV-type weather forecast. A list of a few possible observational projects; weather conditions at times of observations, data tables, charts, sketches, graphs, descriptions of what
Wind Energy-Related Atmospheric Boundary Layer Large-Eddy Simulation Using OpenFOAM: Preprint
Churchfield, M.J.; Vijayakumar, G.; Brasseur, J.G.; Moriarty, P.J.
2010-08-01T23:59:59.000Z
This paper develops and evaluates the performance of a large-eddy simulation (LES) solver in computing the atmospheric boundary layer (ABL) over flat terrain under a variety of stability conditions, ranging from shear driven (neutral stratification) to moderately convective (unstable stratification).
Ris-PhD-Report Ecosystem-atmosphere exchange of carbon in
Risø-PhD-Report Ecosystem-atmosphere exchange of carbon in a heathland under future climatic conditions Merete Bang Selsted Risø-PhD-63(EN) July 2010 #12;Author: Merete Bang Selsted Title: Ecosystem environmental factors have separately and in combination effect on ecosystem processes. Terrestrial ecosystems
A PHYSICALLY-BASED SCHEME FOR THE URBAN ENERGY BUDGET IN ATMOSPHERIC MODELS
, Urban energy balance, Urban water balance, Urban boundary layer. 1. Introduction Due to the complexityA PHYSICALLY-BASED SCHEME FOR THE URBAN ENERGY BUDGET IN ATMOSPHERIC MODELS VALÉRY MASSON Centre any city in the world, for any time or weather condition (heat island cooling by night, urban wake
Technique to study corrosion in fluctuating gaseous atmospheres
Ficalora, P.J.; Godfrey, T.G.
1983-07-01T23:59:59.000Z
The hot metal surfaces in a combustion system operating with an imperfect air-to-fuel mix experience a variation of corrosion potential. For example, the corrosion conditions can vary from reducing to oxidizing as the combustion conditions vary from rich to lean. This variation of conditions is particularly important in combustion systems utilizing sulfur-containing fuels since small variations in the sulfur partial pressure can cause catastrophic corrosion conditions. In an atmospheric fluidized-bed combustor (AFBC), coal is burned in the presence of a sulfur sorber, CaO or MgO. The alkaline oxide reacts with sulfur dioxide, the combustion product of the sulfur in the coal, to form the corresponding sulfate. Hence, the oxygen and sulfur dioxide partial pressures are controlled by the input conditions (air-coal ratio) as well as the sorption process. Figure 1 shows the observed variation of the oxygen partial pressure in an AFBC as a function of time and bed position. Clearly, fluctuations occur in a time interval of seconds, and the oxygen partial pressure can vary over approximately ten orders of magnitude. Corrosion in these fluctuating gaseous environments is being studied by measuring the resistance change of a heated metal filament specimen while it reacts with alternating oxidizing and sulfidizing gas pulses.
Suresh, Anil K [ORNL; Pelletier, Dale A [ORNL; Wang, Wei [ORNL; Broich, Michael L [ORNL; Moon, Ji Won [ORNL; Gu, Baohua [ORNL; Allison, David P [ORNL; Joy, David Charles [ORNL; Phelps, Tommy Joe [ORNL; Doktycz, Mitchel John [ORNL
2011-01-01T23:59:59.000Z
Nanocrystallites have garnered substantial interest due to their varying applications including catalysis. Consequently important aspects related to control of shape/size and syntheses through economical and non-hazardous means are desirable. Highly efficient bioreduction based natural fabrication approaches that utilize microbes and or -plant extracts are poised to meet these needs. Here we show that the gamma- proteobacterium, Shewanella oneidensis MR-1, can reduce tetrachloro aurate (III) ions, producing discrete extracellular spherical gold nanocrystallites. The particles were homogeneous with multiple size distributions and produced under ambient conditions at high yield, 88% of theoretical maximum. Further characterization revealed that the particles consist of spheres in the size range of 2-50 nm, with an average of 12 5 nm. The nanoparticles were hydrophilic, biocompatible, and resisted aggregation even after several months. The particles are likely capped by a detachable protein/peptide coat. UV-vis and Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectra and transmission electron microscopy measurements confirmed the formation as well the crystalline nature of the nanoparticles. The antibacterial activity of these gold nanoparticles was assessed using Gram-negative (E. coli and S. oneidensis) and Gram-positive (B. subtilis) bacteria. Toxicity assessments divulged that the particles were neither toxic nor inhibitory to any of these bacteria.
Necessary conditions for stabilization agreements
Yang, Zili.; Jacoby, Henry D.
The Climate Convention calls for stabilization of atmospheric concentrations of greenhouse gases. This paper considers the issues that must be faced in formulating a plan to meet any such target, using a proposed CO2 level ...
Shporer, Avi
2015-01-01T23:59:59.000Z
We identify 3 Kepler transiting planet systems, Kepler-7, Kepler-12, and Kepler-41, whose orbital phase-folded light curves are dominated by planetary atmospheric processes including thermal emission and reflected light, while the impact of non-atmospheric (i.e. gravitational) processes, including beaming (Doppler boosting) and tidal ellipsoidal distortion, is negligible. Therefore, those systems allow a direct view of their atmospheres without being hampered by the approximations used in the inclusion of both atmospheric and non-atmospheric processes when modeling the phase curve shape. Here we analyze Kepler-12b and Kepler-41b atmosphere based on their Kepler phase curve, while the analysis of Kepler-7b was presented elsewhere. The model we used efficiently computes reflection and thermal emission contributions to the phase curve, including inhomogeneous atmospheric reflection due to longitudinally varying cloud coverage. We confirm Kepler-12b and Kepler-41b show a westward phase shift between the brightest...
High voltage pulse conditioning
Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)
1990-01-01T23:59:59.000Z
Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.
Lokhandwala, Kaaeid A. (Union City, CA)
2000-01-01T23:59:59.000Z
A process for conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas, so that it can be used as combustion fuel to run gas-powered equipment, including compressors, in the gas field or the gas processing plant. Compared with prior art processes, the invention creates lesser quantities of low-pressure gas per unit volume of fuel gas produced. Optionally, the process can also produce an NGL product.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirtA Journey Inside theFacebookTechnicalBio-InspiredtechnologiesTechnology TransferTerms and Conditions
Boyer, Edmond
decayed ice cover, we found surprisingly high pCO2sw (~290320 matm), considering that surface waterFurther observations of a decreasing atmospheric CO2 uptake capacity in the Canada Basin (Arctic as an atmospheric CO2 sink under the summertime ice-free conditions expected in the near future. Beneath a heavily
01/14 Ver. 2.1 Atmospheric,OceanicandSpaceSciences
Eustice, Ryan
Atmospheric Chemistry, Aerosols & Air Quality Atmospheric Dynamics Climate, Climate Modeling & Climate Change01/14 Ver. 2.1 Atmospheric,OceanicandSpaceSciences Atmospheric, Oceanic & Space Sciences University Applied Climate Research areas Atmospheric Science Research Areas Atmosphere Biosphere Interactions
''Nuclear Winter'': A diagnosis of atmospheric general circulation model simulations
Covey, C.; Thompson, S.L.; Schneider, S.H.
1985-06-20T23:59:59.000Z
We investigate the adiabatic and diabatic thermal balance of an atmospheric general circulation model (GCM) under two conditions: the control case, representing today's atmosphere, and a ''nuclear winter'' scenario in which virtually all sunlight in northern hemisphere and mid-latitudes is absorbed in the upper troposphere by prescribed dense smoke clouds hypothesized to result from the burning of many cities in a nuclear war. We also examine the changes in moisture and cloudiness simulated by the model. Our object is to examine the reliability of existing simulations of the climatic response to assumed dense, widespread, high-altitude smoke and to identify improvements needed in model parameterizations. We find that in the smoke-perturbed case our model simulation of land surface temperature is particularly influenced (i.e., warmed) by parameterized diffusion of heat downward from the lower troposphere. In turn the lower troposphere over land is supplied with heat transported from the relatively warm oceans. Thermal balance in the perturbed atmosphere as a whole is dominated by intense solar heating of the upper troposphere smoke layer in mid-latitudes balanced by parameterized dry convection and large-scale dynamical heat transport. Clouds largely disappear in the mid to upper troposphere in smoke-affected regions as a consequence of a decrease in local relative humidity that results from temperature increases and, to a smaller extent, from a reduction of vertical moisture transport. The computation of substantial downward vertical heat diffusion into the lowest model layer is almost certainly an overestimate for the smoke-perturbed conditions of high vertical stability.
February 17, 2002 14:24 WorldScienti c/ws lula Conservative Discretization of the
Preziosi, Luigi
February 17, 2002 14:24 WorldScienti c/ws lula Chapter 1 Conservative Discretization:24 WorldScienti c/ws lula 2 Conservative Discretization of the Boltzmann Equation and the Semicontinuous
-focusing. It was predicted that diffractional spreading is suppressed for discrete solitons,4,5 which are known to possess demonstrate, for the first time to our knowledge, the existence of discrete gap solitons that display
The Upper Atmosphere of HD17156b
T. T. Koskinen; A. D. Aylward; S. Miller
2008-11-28T23:59:59.000Z
HD17156b is a newly-found transiting extrasolar giant planet (EGP) that orbits its G-type host star in a highly eccentric orbit (e~0.67) with an orbital semi-major axis of 0.16 AU. Its period, 21.2 Earth days, is the longest among the known transiting planets. The atmosphere of the planet undergoes a 27-fold variation in stellar irradiation during each orbit, making it an interesting subject for atmospheric modelling. We have used a three-dimensional model of the upper atmosphere and ionosphere for extrasolar gas giants in order to simulate the progress of HD17156b along its eccentric orbit. Here we present the results of these simulations and discuss the stability, circulation, and composition in its upper atmosphere. Contrary to the well-known transiting planet HD209458b, we find that the atmosphere of HD17156b is unlikely to escape hydrodynamically at any point along the orbit, even if the upper atmosphere is almost entirely composed of atomic hydrogen and H+, and infrared cooling by H3+ ions is negligible. The nature of the upper atmosphere is sensitive to to the composition of the thermosphere, and in particular to the mixing ratio of H2, as the availability of H2 regulates radiative cooling. In light of different simulations we make specific predictions about the thermosphere-ionosphere system of HD17156b that can potentially be verified by observations.
Lacey, Ph.D, P.E., Ronald E. [Texas A& M University
2012-07-16T23:59:59.000Z
Discrete Event Modeling of Algae Cultivation and Harvesting at Commercial Scale: Capital Costs, Operating Costs, and System Bottlenecks
Near Maximal Atmospheric Neutrino Mixing in Neutrino Mass Models with Two Texture Zeros
S. Dev; Radha Raman Gautam; Lal Singh; Manmohan Gupta
2014-08-05T23:59:59.000Z
The implications of a large value of the effective Majorana neutrino mass for a class of two texture zero neutrino mass matrices have been studied in the flavor basis. It is found that these textures predict near maximal atmospheric neutrino mixing angle in the limit of large effective Majorana neutrino mass. It is noted that this prediction is independent of the values of solar and reactor neutrino mixing angles. We present the symmetry realization of these textures using the discrete cyclic group $Z_3$. It is found that the texture zeros realised in this work remain stable under renormalization group running of the neutrino mass matrix from the seesaw scale to the electroweak scale, at one loop level.
Mass spectrometric approaches for chemical characterisation of atmospheric aerosols: critical
Nizkorodov, Sergey
Mass spectrometric approaches for chemical characterisation of atmospheric aerosols: critical. Atmospheric aerosols have profound effects on the environment through several physicochemical processes on the respiratory and cardiovascular systems. Understanding aerosol atmospheric chemistry and its environmental
Atmospheric processing of organic aerosols G. Barney Ellison
Ellison, Barney
Atmospheric processing of organic aerosols G. Barney Ellison Department of Chemistry suggest a chemical model for the composition, structure, and atmospheric processing of organic aerosols component of atmospheric aerosols. The proposed model organic aerosol is an "inverted micelle" consisting
Oceanography and Meteorology Building.The Doppler weather radar on the roof of the building is a campus Mobile Atmospheric Research and Teaching Radar (SMART-R).This radar is used in national and international
Pulsed atmospheric fluidized bed combustion
Not Available
1989-11-01T23:59:59.000Z
In order to verify the technical feasibility of the MTCI Pulsed Atmospheric Fluidized Bed Combustor technology, a laboratory-scale system was designed, built and tested. Important aspects of the operational and performance parameters of the system were established experimentally. A considerable amount of the effort was invested in the initial task of constructing an AFBC that would represent a reasonable baseline against which the performance of the PAFBC could be compared. A summary comparison of the performance and emissions data from the MTCI 2 ft {times} 2 ft facility (AFBC and PAFBC modes) with those from conventional BFBC (taller freeboard and recycle operation) and circulating fluidized bed combustion (CFBC) units is given in Table ES-1. The comparison is for typical high-volatile bituminous coals and sorbents of average reactivity. The values indicated for BFBC and CFBC were based on published information. The AFBC unit that was designed to act as a baseline for the comparison was indeed representative of the larger units even at the smaller scale for which it was designed. The PAFBC mode exhibited superior performance in relation to the AFBC mode. The higher combustion efficiency translates into reduced coal consumption and lower system operating cost; the improvement in sulfur capture implies less sorbent requirement and waste generation and in turn lower operating cost; lower NO{sub x} and CO emissions mean ease of site permitting; and greater steam-generation rate translates into less heat exchange surface area and reduced capital cost. Also, the PAFBC performance generally surpasses those of conventional BFBC, is comparable to CFBC in combustion and NO{sub x} emissions, and is better than CFBC in sulfur capture and CO emissions even at the scaled-down size used for the experimental feasibility tests.
An investigation of the atmospheric physical conditions associated with microwave propagation
Riggs, Lowell Pogue
1958-01-01T23:59:59.000Z
wm 1000ed fer this periods oooarriag deria0 the cise ef the freatsl pass s0e The wiads wore aet fawsrshle fot' Ap fsrastioa swd it is thoa0ht that. ths presaaoo of dissiyatiag chaaderstoras wich tho frsacsl yass- sgo scold have hoes tha priowry... eaaepc chat the tsp ef the ~Cetera Layer was abase 3000 feet sa4 ia tha pasC fe?ease st?4ias this had bess ~ 4sterrest ts Ap forostim. Appsreatly, Che 1001 swr- fase relative h@a14icy wss streag oaosgh Co fera s ~istwro gra4iesC with the evsrmLL valse...
Kocum, C.; Ayhan, H. [Biomedical Engineering Department, Baskent University, Ankara 06530 (Turkey); Chemistry Department, Biochemistry Division, Mugla University, Faculty of Science, Koetekli, 48170 Mugla (Turkey)
2007-06-15T23:59:59.000Z
The design of a uniform glow discharge plasma system operating without vacuum is presented. A full-bridge switching circuit was used to switch the transformers. The primary windings of transformers were connected in parallel, but in opposite phase to double the output voltage. Theoretically, 20 000 V{sub pp} was obtained. Rectangle copper electrodes were used, and placed parallel to each other. To prevent the spark production that is, to obtain uniformity, two 2 mm Teflon sheets were glued to the electrodes. However, it was observed that the operating frequency also affected the uniformity. For the system presented here, the frequency at which more uniformity was obtained was found to be 14 kHz.
Aizenberg, Igor
Fresnel Functions and Transforms in an Arbitrary Discrete Basis Igor Aizenberg, Senior Member, IEEE, and Jaakko T. Astola, Fellow, IEEE Abstract--The idea of generalized Fresnel functions, which traces back discrete Fresnel functions and the generalized discrete Fresnel transforms for an arbitrary basis
Peraire, Jaime
adaptation for high-order discretizations and simplex, cut-cell mesh generation. First, output-based mesh is presented for high-order (p > 1) discretizations, driven by an output-error estimate obtained fromA Simplex Cut-Cell Adaptive Method for High-Order Discretizations of the Compressible Navier
Peraire, Jaime
A Simplex Cut-Cell Adaptive Method for High-Order Discretizations of the Compressible Navier;A Simplex Cut-Cell Adaptive Method for High-Order Discretizations of the Compressible Navier adaptation for high-order discretizations and simplex, cut-cell mesh generation. First, output-based mesh
Doty, Sharon Lafferty
The faculty and students in the Atmospheric Sciences Department use physics, chemistry chemistry Atmospheric fluid dynamics Biosphere interactions Climate variability Clouds & storms Radiative, and mathematics to better understand the atmosphere and improve the prediction of its future state, both over
Comparative Analysis of Urban Atmospheric Aerosol by Particle...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Analysis of Urban Atmospheric Aerosol by Particle-Induced X-ray Emission (PIXE), Proton Elastic Scattering Analysis Comparative Analysis of Urban Atmospheric Aerosol by...
Fehner and Gosling, Atmospheric Nuclear Weapons Testing, 1951...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Atmospheric Nuclear Weapons Testing, 1951-1963. Battlefield of the Cold War: The Nevada Test Site, Volume I Fehner and Gosling, Atmospheric Nuclear Weapons Testing, 1951-1963....
Diesel and Gasoline Engine Emissions: Characterization of Atmosphere...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Characterization of Atmosphere Composition and Health Responses to Inhaled Emissions Diesel and Gasoline Engine Emissions: Characterization of Atmosphere Composition and Health...
Composition and Reactions of Atmospheric Aerosol Particles
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
large portion of the microscopic particles floating in the air originate from incomplete combustion of coal and oil and from dust storms. Once in the atmosphere, they can have...
Adaptive control for Mars atmospheric flight
Restrepo, Carolina Isabel
2009-05-15T23:59:59.000Z
landing accuracy requirements for a manned space vehicle make it necessary to ?y a controlled entry trajectory rather than a more robust ballistic entry trajectory used for some robotic missions. The large variations in Mars atmospheric properties make a...
Transport impacts on atmosphere and climate: Aviation
2010-01-01T23:59:59.000Z
Environment 44 (2010) 4678–4734 Brunner, D. , Staehelin,Environment 44 (2010) 4678–4734 Vedantham, A. , Wuebbles,Environment 44 (2010) 4678–4734 global atmosphere’. In:
Illich, Paul Anthony
1990-01-01T23:59:59.000Z
CONDITIONED CHANGES IN PAIN REACTIVITY: CONDITIONED STIMULI ELICIT HYPOALGESIA UNDER A WIDE RANGE OF TEST CONDITIONS A Thesis by PAUL ANTHONY ILLICH Submitted to the Office Of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1990 Major Subject: Psychology Conditioned Changes in Pain Reactivity: Conditioned Stimuli elicit Hypoalgesia Under a Wide Range of Test Conditions A Thesis by Paul Anthony Illich Approved...
Scalar potential model of redshift and discrete redshift
John C. Hodge
2006-02-15T23:59:59.000Z
On the galactic scale the universe is inhomogeneous and redshift $z$ is occasionally less than zero. A scalar potential model (SPM) that links the galaxy scale $z$ to the cosmological scale $z$ of the Hubble Law is postulated. Several differences among galaxy types suggest that spiral galaxies are Sources and that early type, lenticular, and irregular galaxies are Sinks of a scalar potential field. The morphology-radius and the intragalactic medium cluster observations support the movement of matter from Source galaxies to Sink galaxies. A cell structure of galaxy groups and clusters is proposed to resolve a paradox concerning the scalar potential like the Olber's paradox concerning light. For the sample galaxies, the ratio of the luminosity of Source galaxies to the luminosity of Sink galaxies approaches $2.7 \\pm 0.1$. An equation is derived from sample data, which is anisotropic and inhomogeneous, relating $z$ of and the distance $D$ to galaxies. The calculated $z$ has a correlation coefficient of 0.88 with the measured $z$ for a sample of 32 spiral galaxies with $D$ calculated using Cepheid variable stars. The equation is consistent with $zSPM of $z$ provides a physical basis for the $z$ of particle photons. Further, the SPM qualitatively suggests the discrete variations in $z$, which was reported by W. G. Tifft, 1997, Astrophy. J. 485, 465 and confirmed by others, are consistent with the SPM.
Discrete-Time ARMAv Model-Based Optimal Sensor Placement
Song Wei; Dyke, Shirley J. [Washington University in St. Louis, St. Louis, MO 63130 (United States)
2008-07-08T23:59:59.000Z
This paper concentrates on the optimal sensor placement problem in ambient vibration based structural health monitoring. More specifically, the paper examines the covariance of estimated parameters during system identification using auto-regressive and moving average vector (ARMAv) model. By utilizing the discrete-time steady state Kalman filter, this paper realizes the structure's finite element (FE) model under broad-band white noise excitations using an ARMAv model. Based on the asymptotic distribution of the parameter estimates of the ARMAv model, both a theoretical closed form and a numerical estimate form of the covariance of the estimates are obtained. Introducing the information entropy (differential entropy) measure, as well as various matrix norms, this paper attempts to find a reasonable measure to the uncertainties embedded in the ARMAv model estimates. Thus, it is possible to select the optimal sensor placement that would lead to the smallest uncertainties during the ARMAv identification process. Two numerical examples are provided to demonstrate the methodology and compare the sensor placement results upon various measures.
Non-Abelian discrete gauge symmetries in F-theory
Grimm, Thomas W; Regalado, Diego
2015-01-01T23:59:59.000Z
The presence of non-Abelian discrete gauge symmetries in four-dimensional F-theory compactifications is investigated. Such symmetries are shown to arise from seven-brane configurations in genuine F-theory settings without a weak string coupling description. Gauge fields on mutually non-local seven-branes are argued to gauge both R-R and NS-NS two-form bulk axions. The gauging is completed into a generalisation of the Heisenberg group with either additional seven-brane gauge fields or R-R bulk gauge fields. The former case relies on having seven-brane fluxes, while the latter case requires torsion cohomology and is analysed in detail through the M-theory dual. Remarkably, the M-theory reduction yields an Abelian theory that becomes non-Abelian when translated into the correct duality frame to perform the F-theory limit. The reduction shows that the gauge coupling function depends on the gauged scalars and transforms non-trivially as required for the groups encountered. This field dependence agrees with the exp...
Non-Abelian discrete gauge symmetries in F-theory
Thomas W. Grimm; Tom G. Pugh; Diego Regalado
2015-04-23T23:59:59.000Z
The presence of non-Abelian discrete gauge symmetries in four-dimensional F-theory compactifications is investigated. Such symmetries are shown to arise from seven-brane configurations in genuine F-theory settings without a weak string coupling description. Gauge fields on mutually non-local seven-branes are argued to gauge both R-R and NS-NS two-form bulk axions. The gauging is completed into a generalisation of the Heisenberg group with either additional seven-brane gauge fields or R-R bulk gauge fields. The former case relies on having seven-brane fluxes, while the latter case requires torsion cohomology and is analysed in detail through the M-theory dual. Remarkably, the M-theory reduction yields an Abelian theory that becomes non-Abelian when translated into the correct duality frame to perform the F-theory limit. The reduction shows that the gauge coupling function depends on the gauged scalars and transforms non-trivially as required for the groups encountered. This field dependence agrees with the expectations for the kinetic mixing of seven-branes and is unchanged if the gaugings are absent.
Lattice Gauge Fields and Discrete Noncommutative Yang-Mills Theory
J. Ambjorn; Y. M. Makeenko; J. Nishimura; R. J. Szabo
2000-04-21T23:59:59.000Z
We present a lattice formulation of noncommutative Yang-Mills theory in arbitrary even dimensionality. The UV/IR mixing characteristic of noncommutative field theories is demonstrated at a completely nonperturbative level. We prove a discrete Morita equivalence between ordinary Yang-Mills theory with multi-valued gauge fields and noncommutative Yang-Mills theory with periodic gauge fields. Using this equivalence, we show that generic noncommutative gauge theories in the continuum can be regularized nonperturbatively by means of {\\it ordinary} lattice gauge theory with 't~Hooft flux. In the case of irrational noncommutativity parameters, the rank of the gauge group of the commutative lattice theory must be sent to infinity in the continuum limit. As a special case, the construction includes the recent description of noncommutative Yang-Mills theories using twisted large $N$ reduced models. We study the coupling of noncommutative gauge fields to matter fields in the fundamental representation of the gauge group using the lattice formalism. The large mass expansion is used to describe the physical meaning of Wilson loops in noncommutative gauge theories. We also demonstrate Morita equivalence in the presence of fundamental matter fields and use this property to comment on the calculation of the beta-function in noncommutative quantum electrodynamics.
Defining integrals over connections in the discretized gravitational functional integral
V. M. Khatsymovsky
2010-05-01T23:59:59.000Z
Integration over connection type variables in the path integral for the discrete form of the first order formulation of general relativity theory is studied. The result (a generalized function of the rest of variables of the type of tetrad or elementary areas) can be defined through its moments, i. e. integrals of it with the area tensor monomials. In our previous paper these moments have been defined by deforming integration contours in the complex plane as if we had passed to an Euclidean-like region. In the present paper we define and evaluate the moments in the genuine Minkowsky region. The distribution of interest resulting from these moments in this non-positively defined region contains the divergences. We prove that the latter contribute only to the singular (\\dfun like) part of this distribution with support in the non-physical region of the complex plane of area tensors while in the physical region this distribution (usual function) confirms that defined in our previous paper which decays exponentially at large areas. Besides that, we evaluate the basic integrals over which the integral over connections in the general path integral can be expanded.
Entrainment of coarse grains using a discrete particle model
Valyrakis, Manousos, E-mail: Manousos.Valyrakis@glasgow.ac.uk [Lecturer in Water and Environmental Engineering, Rankine 817b, University of Glasgow, Glasgow G12 8LT (United Kingdom); Arnold, Roger B. Jr. [Environmental Engineer, Arcadis, USA (formerly: research assistant Virginia Tech, USA) (United States)
2014-10-06T23:59:59.000Z
Conventional bedload transport models and incipient motion theories relying on a time-averaged boundary shear stress are incapable of accounting for the effects of fluctuating near-bed velocity in turbulent flow and are therefore prone to significant errors. Impulse, the product of an instantaneous force magnitude and its duration, has been recently proposed as an appropriate criterion for quantifying the effects of flow turbulence in removing coarse grains from the bed surface. Here, a discrete particle model (DPM) is used to examine the effects of impulse, representing a single idealized turbulent event, on particle entrainment. The results are classified according to the degree of grain movement into the following categories: motion prior to entrainment, initial dislodgement, and energetic displacement. The results indicate that in all three cases the degree of particle motion depends on both the force magnitude and the duration of its application and suggest that the effects of turbulence must be adequately accounted for in order to develop a more accurate method of determining incipient motion. DPM is capable of simulating the dynamics of grain entrainment and is an appropriate tool for further study of the fundamental mechanisms of sediment transport.
Thermal Neutron Detectors with Discrete Anode Pad Readout
Yu,B.; Schaknowski, N.A., Smith, G.C., DeGeronimo, G., Vernon, E.O.
2008-10-19T23:59:59.000Z
A new two-dimensional thermal neutron detector concept that is capable of very high rates is being developed. It is based on neutron conversion in {sup 3}He in an ionization chamber (unity gas gain) that uses only a cathode and anode plane; there is no additional electrode such as a Frisch grid. The cathode is simply the entrance window, and the anode plane is composed of discrete pads, each with their own readout electronics implemented via application specific integrated circuits. The aim is to provide a new generation of detectors with key characteristics that are superior to existing techniques, such as higher count rate capability, better stability, lower sensitivity to background radiation, and more flexible geometries. Such capabilities will improve the performance of neutron scattering instruments at major neutron user facilities. In this paper, we report on progress with the development of a prototype device that has 48 x 48 anode pads and a sensitive area of 24cm x 24cm.
Metrics for Availability Analysis Using a Discrete Event Simulation Method
Schryver, Jack C [ORNL; Nutaro, James J [ORNL; Haire, Marvin Jonathan [ORNL
2012-01-01T23:59:59.000Z
The system performance metric 'availability' is a central concept with respect to the concerns of a plant's operators and owners, yet it can be abstract enough to resist explanation at system levels. Hence, there is a need for a system-level metric more closely aligned with a plant's (or, more generally, a system's) raison d'etre. Historically, availability of repairable systems - intrinsic, operational, or otherwise - has been defined as a ratio of times. This paper introduces a new concept of availability, called endogenous availability, defined in terms of a ratio of quantities of product yield. Endogenous availability can be evaluated using a discrete event simulation analysis methodology. A simulation example shows that endogenous availability reduces to conventional availability in a simple series system with different processing rates and without intermediate storage capacity, but diverges from conventional availability when storage capacity is progressively increased. It is shown that conventional availability tends to be conservative when a design includes features, such as in - process storage, that partially decouple the components of a larger system.
Atmospheric State, Cloud Microphysics and Radiative Flux
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Mace, Gerald
Atmospheric thermodynamics, cloud properties, radiative fluxes and radiative heating rates for the ARM Southern Great Plains (SGP) site. The data represent a characterization of the physical state of the atmospheric column compiled on a five-minute temporal and 90m vertical grid. Sources for this information include raw measurements, cloud property and radiative retrievals, retrievals and derived variables from other third-party sources, and radiative calculations using the derived quantities.
Air Activation Following an Atmospheric Explosion
Lowrey, Justin D.; McIntyre, Justin I.; Prichard, Andrew W.; Gesh, Christopher J.
2013-03-13T23:59:59.000Z
In addition to thermal radiation and fission products, nuclear explosions result in a very high flux of unfissioned neutrons. Within an atmospheric nuclear explosion, these neutrons can activate the various elemental components of natural air, potentially adding to the radioactive signature of the event as a whole. The goal of this work is to make an order-of-magnitude estimate of the total amount of air activation products that can result from an atmospheric nuclear explosion.
Quantum light in the turbulent atmosphere
A. A. Semenov; W. Vogel
2009-08-12T23:59:59.000Z
Nonclassical properties of light propagating through the turbulent atmosphere are studied. We demonstrate by numerical simulation that the probability distribution of the transmission coefficient, which characterizes the effects of the atmosphere on the quantum state of light, can be reconstructed by homodyne detection. Nonclassical photon-statistics and, more generally, nonclassical Glauber-Sudarshan functions appear to be more robust against turbulence for weak light fields rather than for bright ones.
Basalt-Atmosphere Interactions on Venus -
Treiman, Allan H.
Atmosphere? Â· CaAl2Si2O8 + SO3 CaSO4 + Al2SiO5 + SiO2 Â Anhydrite + andalusite + quartz !!! Â· Does this reaction proceed? Â Venus atmosphere est'd 0.2 - 0.3 ppt SO3. #12;Reaction Position Â· From this, very possible that SO3 is buffered! Â· But ... SO3 value is not known very well - who knows what is really going
Dimitra Atri; Adrian L. Melott; Brian C. Thomas
2010-05-03T23:59:59.000Z
A variety of events such as gamma-ray bursts and supernovae may expose the Earth to an increased flux of high-energy cosmic rays, with potentially important effects on the biosphere. Existing atmospheric chemistry software does not have the capability of incorporating the effects of substantial cosmic ray flux above 10 GeV . An atmospheric code, the NASA-Goddard Space Flight Center two-dimensional (latitude, altitude) time-dependent atmospheric model (NGSFC), is used to study atmospheric chemistry changes. Using CORSIKA, we have created tables that can be used to compute high energy cosmic ray (10 GeV - 1 PeV) induced atmospheric ionization and also, with the use of the NGSFC code, can be used to simulate the resulting atmospheric chemistry changes. We discuss the tables, their uses, weaknesses, and strengths.
Simulation of Aerosol Behavior in a Saturated Atmosphere With the CONTAIN Code
Kljenak, Ivo; Mavko, Borut [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia)
2002-07-01T23:59:59.000Z
Experiments on aerosol behavior in an atmosphere containing saturated vapor, which were performed in the KAEVER experimental facility and proposed for the OECD International Standard Problem No. 44, were simulated with the CONTAIN thermal-hydraulic computer code. The purpose of the work was to assess the capability of the CONTAIN code to model aerosol condensation and deposition in a containment of a light-water-reactor nuclear power plant at severe accident conditions. Results of dry and wet aerosol concentrations in the test vessel atmosphere are presented and analyzed. (authors)
Conditional sterility in plants
Meagher, Richard B. (Athens, GA); McKinney, Elizabeth (Athens, GA); Kim, Tehryung (Taejeon, KR)
2010-02-23T23:59:59.000Z
The present disclosure provides methods, recombinant DNA molecules, recombinant host cells containing the DNA molecules, and transgenic plant cells, plant tissue and plants which contain and express at least one antisense or interference RNA specific for a thiamine biosynthetic coding sequence or a thiamine binding protein or a thiamine-degrading protein, wherein the RNA or thiamine binding protein is expressed under the regulatory control of a transcription regulatory sequence which directs expression in male and/or female reproductive tissue. These transgenic plants are conditionally sterile; i.e., they are fertile only in the presence of exogenous thiamine. Such plants are especially appropriate for use in the seed industry or in the environment, for example, for use in revegetation of contaminated soils or phytoremediation, especially when those transgenic plants also contain and express one or more chimeric genes which confer resistance to contaminants.
E. Siegmann
2000-08-22T23:59:59.000Z
The purpose of this analysis is to describe the condition of commercial Zircaloy clad fuel as it is received at the Yucca Mountain Project (YMP) site. Most commercial nuclear fuel is encased in Zircaloy cladding. This analysis is developed to describe cladding degradation from the expected failure modes. This includes reactor operation impacts including incipient failures, potential degradation after reactor operation during spent fuel storage in pool and dry storage and impacts due to transportation. Degradation modes include cladding creep, and delayed hydride cracking during dry storage and transportation. Mechanical stresses from fuel handling and transportation vibrations are also included. This Analysis and Model Report (AMR) does not address any potential damage to assemblies that might occur at the YMP surface facilities. Ranges and uncertainties have been defined. This analysis will be the initial boundary condition for the analysis of cladding degradation inside the repository. In accordance with AP-2.13Q, ''Technical Product Development Planning'', a work plan (CRWMS M&O 2000c) was developed, issued, and utilized in the preparation of this document. There are constraints, caveats and limitations to this analysis. This cladding degradation analysis is based on commercial Pressurized Water Reactor (PWR) fuel with Zircaloy cladding but is applicable to Boiling Water Reactor (BWR) fuel. Reactor operating experience for both PWRs and BWRs is used to establish fuel reliability from reactor operation. It is limited to fuel exposed to normal operation and anticipated operational occurrences (i.e. events which are anticipated to occur within a reactor lifetime), and not to fuel that has been exposed to severe accidents. Fuel burnup projections have been limited to the current commercial reactor licensing environment with restrictions on fuel enrichment, oxide coating thickness and rod plenum pressures. The information provided in this analysis will be used in evaluating the post-closure performance of the Monitored Geologic Repository (MGR) in relation to waste form degradation.
Switching Between Discrete and Continuous Process Models to Predict Molecular Genetic Activity
Weld, Daniel Sabey
1984-05-01T23:59:59.000Z
Two kinds of process models have been used in programs that reason about change: Discrete and continuous models. We describe the design and implementation of a qualitative simulator, PEPTIDE, which uses both kinds of ...
An Efficient Priority Queue for Large FPGA-Based Discrete Event Simulations of
Herbordt, Martin
: Molecular dynamics simulation based on discrete event simulation (DMD) is emerging as an alternative to time Laboratory Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 Abstract
Sensitivity Analysis of Discrete Stochastic Systems Rudiyanto Gunawan,* Yang Cao,y
Cao, Yang
and deterministic analyses show the significance of explicit consideration of the probabilistic natureSensitivity Analysis of Discrete Stochastic Systems Rudiyanto Gunawan,* Yang Cao,y Linda Petzold, University of California, Santa Barbara, California ABSTRACT Sensitivity analysis quantifies the dependence
Representation and Superposition of Discrete Functions and Equations with Parameterized Operations
Wu Zi Qian
2010-07-27T23:59:59.000Z
Existence results for Hilbert's problem 13th mean that any equation constructed by continue functions can be given solution represented as a superposition of continue functions of one variable or of continue functions of two variables. Constructive results for discrete functions are given in this paper that any equation constructed by functions called discrete 3 function for which field of definition is a set containing only -1,0,1 can be given solution represented as a superposition of discrete 3 functions of one variable or of two variables. Formula solution for equation with parameterized operations can be given after introducing four special operators being correspondence among known operations and new operations. These results can be extended to discrete operators and operator equations constructed by them.
Algebraic multigrid for stabilized finite element discretizations of the Navier Stokes equation
Okusanya, Tolulope Olawale, 1972 -
2002-01-01T23:59:59.000Z
A multilevel method for the solution of systems of equations generated by stabilized Finite Element discretizations of the Euler and Navier Stokes equations on generalized unstructured grids is described. The method is ...
Testing and examination of TMI-2 electrical components and discrete devices
Soberano, F.T.
1982-11-01T23:59:59.000Z
This report discusses the approach and results of the in situ test conducted on TMI-2 reactor building electrical components and discrete devices. Also included are the necessary presumptions and assumptions to correlate observed anomalies to the accident.
Theocharis, G.
We present a systematic study of the existence and stability of discrete breathers that are spatially localized in the bulk of a one-dimensional chain of compressed elastic beads that interact via Hertzian contact. The ...
A three dimensional corner balance method for spatial discretization of the transport equation
Richardson, Rebecca Lynn
1994-01-01T23:59:59.000Z
The three-dimensional comer balance method is a new spatial discretization scheme for solving the transport equation on meshes consisting of "layers" of arbitrary polygonal meshes in the x-y plane. It is a conceptually and algebraically simple...
Jansen, Maarten
Contents 1. The Classical Wavelet Transform for Continuous-time and Discrete- time Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 The Continuous Wavelet Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 The Haar wavelet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1
John, Volker
.g., in the simulation of crystal growth [1] or of fuel cells [2]. The numerical solution of the time-dependent Navier results. Even for the two-dimen- sional laminar regime, the question of an optimal discretization approach
F-K Characteristics of the Seismic Response to a Set of Discrete Parallel Fractures
Vetri, Laura
2006-01-01T23:59:59.000Z
We model seismic wave propagation in a reservoir with discrete fracture zones using a finite difference scheme, which implements the Coates-Schoenberg formulation for fractured media. We study the variation of scattered ...
A DUALITY APPROACH TO THE GENEALOGIES OF DISCRETE NON-NEUTRAL WRIGHT-FISHER MODELS
Paris-Sud XI, Université de
A DUALITY APPROACH TO THE GENEALOGIES OF DISCRETE NON-NEUTRAL WRIGHT-FISHER MODELS THIERRY E), there is also some use of the duality concept in an attempt to understand the genealogies of a Wright
Biondini, Gino [Department of Mathematics, State University of New York at Buffalo, Buffalo, New York 14260 (United States)] [Department of Mathematics, State University of New York at Buffalo, Buffalo, New York 14260 (United States); Kova?i?, Gregor [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
2014-03-15T23:59:59.000Z
The inverse scattering transform for the focusing nonlinear Schrödinger equation with non-zero boundary conditions at infinity is presented, including the determination of the analyticity of the scattering eigenfunctions, the introduction of the appropriate Riemann surface and uniformization variable, the symmetries, discrete spectrum, asymptotics, trace formulae and the so-called theta condition, and the formulation of the inverse problem in terms of a Riemann-Hilbert problem. In addition, the general behavior of the soliton solutions is discussed, as well as the reductions to all special cases previously discussed in the literature.
Discrete Sampling Test Plan for the 200-BP-5 Operable Unit
Sweeney, Mark D.
2010-02-04T23:59:59.000Z
The Discrete Groundwater Sampling Project is conducted by the Pacific Northwest National Laboratory (PNNL) on behalf of CH2M HILL Plateau Remediation Company. The project is focused on delivering groundwater samples from proscribed horizons within select groundwater wells residing in the 200-BP-5 Operable Unit (200-BP-5 OU) on the Hanford Site. This document provides the scope, schedule, methodology, and other details of the PNNL discrete sampling effort.
Turbulent heat transfer and friction in a square channel with discrete rib turbulators
McMillin, Robert Dale
1989-01-01T23:59:59.000Z
TURBULENT HEAT TRANSFER AND FRICTION IN A SQUARE CHANNEL WITH DISCRETE RIB TURBULATORS A Thesis by ROBERT DALE iXIGMILLIN Subniitted to the Office of Graduate Studies of Texas AK. M L niversrty in partial fulfillment of the requirements... for the degree of MASTER OF SGIE IGE Deceinber 1989 Major Subject' Mechanical Engineering TURBULENT HEAT TRANSFER AND FRICTION IN A SQUARE CHANNEL WITH DISCRETE RIB TURBULATORS A Thesrs by ROBERT DALE MCMILLI'V Approverl as to style and content...
Space-time as a discrete field noncommutative causal network
G. L. Stavraki
2009-07-02T23:59:59.000Z
The necessity of rejecting the numerical model of geometrical extension is postulated on the basis of the idea of identity of space-time and physical vacuum. An attempt is made to define space-time not via the concept of manifold, but via the store of physical functions defined on it. The new description is based on the commutator representation of the causal structure of operator field theory. It is not the world point, but a universal field supermatrix complex U that is assumed to be the carrier of possible local events. This complex involves a complete set of Heisenberg local field operators together with their spin-group bases in the Fermi-field representation. The fundamental element of the extension is described in the model by the equation of a special commutator algebra closed on two such local complexes U_1 and U_2 "nearest" in the two-sided light-like connection and linked by a single virtual field interaction vertex. The discrete character of the constructed "quantum proximity" equation containing the gravitational constant is associated with the existence of local curvature on the Planck scale. Algebraic closed-ness of the basic equation suggests that the charge symmetry group should be group E_6 with non-standard representations of the fermion and scalar fields. On the basis of the calculated U expression we propose an effective superinvariant Lagrangian with fixed coefficients on the near-Planck scale, from which one can in principle try to obtain a low-energy limit for comparison with the real world.
The coupling of winds, aerosols and chemistry in Titan's atmosphere
Hourdin, Chez Frédéric
REVIEW The coupling of winds, aerosols and chemistry in Titan's atmosphere BY SEBASTIEN LEBONNOIS 1'Ae´ronomie, IPSL, CNRS, BP3, 91371 Verrie`res le Buisson, France The atmosphere of Titan is a complex system, where the observed atmospheric structure of Titan's lower atmosphere (mainly in the stratosphere and troposphere
Phase of atmospheric secondary organic material affects its reactivity
of the reactivity of atmospheric SOM particles. atmospheric chemistry chemical aging organic aerosol collectionPhase of atmospheric secondary organic material affects its reactivity Mikinori Kuwata and Scot T of atmospheric organic particles among solid, semisolid, and liquid phases is of keen current scientific interest
High Altitude Unmanned Air System for Atmospheric Science Missions
Sóbester, András
for an understanding of atmospheric processes across all length scales from global (Earth system modeling) through
Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth
Domagal-Goldman, Shawn D. [Planetary Environments Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S., E-mail: shawn.goldman@nasa.gov [NASA Astrobiology Institute—Virtual Planetary Laboratory (United States)
2014-09-10T23:59:59.000Z
The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.
Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loading: Preprint
Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.
2011-12-01T23:59:59.000Z
Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5 MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.
Quantization of systems with temporally varying discretization. I. Evolving Hilbert spaces
Höhn, Philipp A., E-mail: phoehn@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5 (Canada)
2014-08-15T23:59:59.000Z
A temporally varying discretization often features in discrete gravitational systems and appears in lattice field theory models subject to a coarse graining or refining dynamics. To better understand such discretization changing dynamics in the quantum theory, an according formalism for constrained variational discrete systems is constructed. While this paper focuses on global evolution moves and, for simplicity, restricts to flat configuration spaces R{sup N}, a Paper II [P. A. Höhn, “Quantization of systems with temporally varying discretization. II. Local evolution moves,” J. Math. Phys., e-print http://arxiv.org/abs/arXiv:1401.7731 [gr-qc].] discusses local evolution moves. In order to link the covariant and canonical picture, the dynamics of the quantum states is generated by propagators which satisfy the canonical constraints and are constructed using the action and group averaging projectors. This projector formalism offers a systematic method for tracing and regularizing divergences in the resulting state sums. Non-trivial coarse graining evolution moves lead to non-unitary, and thus irreversible, projections of physical Hilbert spaces and Dirac observables such that these concepts become evolution move dependent on temporally varying discretizations. The formalism is illustrated in a toy model mimicking a “creation from nothing.” Subtleties arising when applying such a formalism to quantum gravity models are discussed.
Semiclassical energy conditions and wormholes
Prado Martin-Moruno
2014-11-17T23:59:59.000Z
We consider the nonlinear energy conditions and their quantum extensions. These new energy conditions behave much better than the usual pointwise energy conditions in the presence of semiclassical quantum effects. Analogous quantum extensions for the linear energy conditions are not always satisfied as one enters the quantum realm, but they can be used to constrain the violation of the classical conditions. Thus, the existence of wormholes supported by a fluid which violates the null energy condition in a controlled way is of particular interest.
Importance of Design Conditions for Sizing Air-Conditioning Plant
Shaban, N.; Maheshwari, G. P.; Suri, R. K.
2000-01-01T23:59:59.000Z
for the proposed and the current design conditions to highlight over- or under-sizing the air-conditioning (A/C) plant capacity. Finally, a number of recommendations are made for architects and designers to use proper design conditions to ensure year-round comfort...
Zheng, Mei
2007-01-01T23:59:59.000Z
Atmospheric Environment 41 (2007) 20612072 Atmospheric polycyclic aromatic hydrocarbons observed). These filters and PUFs were analyzed for particulate phase and gas phase polycyclic aromatic hydrocarbons (PAHs aromatic hydrocarbons (PAHs); Arctic; North Pacific Ocean; Biomass burning ARTICLE IN PRESS www
Pulsed atmospheric fluidized-bed combustor development. Environmental Assessment
Not Available
1992-05-01T23:59:59.000Z
Pulsed atmospheric fluidized-bed combustion (PAFBC) is a unique and innovative coal-fueled technology that has the potential to meet these conditions and provide heat and/or process steam to small industrial, commercial, institutional and residential complexes. The potential of Pulse Atmospheric Fluidized Bed Combustion (PAFBC) technology has been amply demonstrated under the sponsorship of a previous DOE/METC contract (DE-AC21-88MC25069). The environmental performance of a coal-fired laboratory-scale system (1.5 million British Thermal Units per hour) (MMBtu/hr) significantly surpassed that of conventional bubbling and circulating fluidized-bed combustion units (see Table 1 for performance comparison). Prompted by these encouraging results in combustion, sulfur capture, emissions control, and enhanced heat transfer, Island Creek Coal Company (ICC) and Baltimore Thermal Energy Corporation expressed interest in the technology and offered to participate by providing host sites for field testing. EA`s have been submitted independently for each of these field test sites. This submission addresses the preliminary testing of the PAFBC unit at Manufacturing and Technology Conversion International`s (MTCI) Baltimore, MD facility.
Optimization of Air Conditioning Cycling
Seshadri, Swarooph
2012-10-19T23:59:59.000Z
Systems based on the vapor compression cycle are the most widely used in a variety of air conditioning applications. Despite the vast growth of modern control systems in the field of air conditioning systems, industry standard control is still...
Optimization of Air Conditioning Cycling
Seshadri, Swarooph
2012-10-19T23:59:59.000Z
Systems based on the vapor compression cycle are the most widely used in a variety of air conditioning applications. Despite the vast growth of modern control systems in the field of air conditioning systems, industry standard control is still...
Gajic, Zoran
responses of a higher-order linear discrete- time system using MATLAB. We study system impulse, step , and find the impulse response of the reduced order system for k=0:1:40. Part 3. Find the step response using the MATLAB function dstep. Plot the step response k=0:1:14 and k=0:1:40. Comment
Magnetized Atmospheres around Accreting Neutron Stars
S. Zane; R. Turolla; A. Treves
2000-02-01T23:59:59.000Z
We present a detailed investigation of atmospheres around accreting neutron stars with high magnetic field ($B\\gtrsim 10^{12}$ G) and low luminosity ($L\\lesssim 10^{33}$ erg/s). We compute the atmospheric structure, intensity and emergent spectrum for a plane-parallel, pure hydrogen medium by solving the transfer equations for the normal modes coupled to the hydrostatic and energy balance equations. The hard tail found in previous investigations for accreting, non-magnetic neutron stars with comparable luminosity is suppressed and the X-ray spectrum, although still harder than a blackbody at the star effective temperature, is nearly planckian in shape. Spectra from accreting atmospheres, both with high and low fields, are found to exhibit a significant excess at optical wavelengths above the Rayleigh-Jeans tail of the X-ray continuum.
Super Kamiokande results: atmospheric and solar neutrinos
M. Ishitsuka; for the Super-Kamiokande Collaboration
2004-06-28T23:59:59.000Z
Atmospheric neutrino and solar neutrino data from the first phase of Super-Kamiokande (SK-I) are presented. The observed data are used to study atmospheric and solar neutrino oscillations. Zenith angle distributions from various atmospheric neutrino data samples are used to estimate the neutrino oscillation parameter region. In addition, a new result of the $L/E$ measurement is presented. A dip in the $L/E$ distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The energy spectrum and the time variation such as day/night and seasonal differences of solar neutrino flux are measured in Super-Kamiokande. The neutrino oscillation parameters are strongly constrained from those measurements.
Atmospheric Pressure Plasma Process And Applications
Peter C. Kong; Myrtle
2006-09-01T23:59:59.000Z
This paper provides a general discussion of atmospheric-pressure plasma generation, processes, and applications. There are two distinct categories of atmospheric-pressure plasmas: thermal and nonthermal. Thermal atmospheric-pressure plasmas include those produced in high intensity arcs, plasma torches, or in high intensity, high frequency discharges. Although nonthermal plasmas are at room temperatures, they are extremely effective in producing activated species, e.g., free radicals and excited state atoms. Thus, both thermal and nonthermal atmosphericpressure plasmas are finding applications in a wide variety of industrial processes, e.g. waste destruction, material recovery, extractive metallurgy, powder synthesis, and energy conversion. A brief discussion of recent plasma technology research and development activities at the Idaho National Laboratory is included.
When Does Aid Conditionality Work?
Montinola, Gabriella R.
2010-01-01T23:59:59.000Z
2005, the Group of Eight (G8) nations committed to increaseprogram conditions. Given the G8 industrialized nations’
Controlled Microdroplet Transport in an Atmospheric Pressure Microplasma
Maguire, P D; Kelsey, C P; Bingham, A; Montgomery, E P; Bennet, E D; Potts, H E; Rutherford, D; McDowell, D A; Diver, D A; Mariotti, D
2015-01-01T23:59:59.000Z
We report the controlled injection of near-isolated micron-sized liquid droplets into a low temperature He-Ne steady-state rf plasma at atmospheric pressure. The H2O droplet stream is constrained within a 2 mm diameter quartz tube. Imaging at the tube exit indicates a log-normal droplet size distribution with an initial count mean diameter of 15 micrometers falling to 13 micrometers with plasma exposure. The radial velocity profile is approximately parabolic indicating near laminar flow conditions with the majority of droplets travelling at >75% of the local gas speed and having a plasma transit time of chemistry effects. The successful demonstration of controlled microdroplet streams opens up possibilities for gas-phase microreactors and remote delivery of active species for pla...
Contamination of Dark Matter Experiments from Atmospheric Magnetic Dipoles
A. Bueno; M. Masip; P. Sánchez-Lucas; N. Setzer
2013-10-14T23:59:59.000Z
Dark matter collisions with heavy nuclei (Xe, Ge, Si, Na) may produce recoils observable at direct-search experiments. Given that some of these experiments are yielding conflicting information, however, it is worth asking if physics other than dark matter may produce similar nuclear recoils. We examine under what conditions an atmospherically-produced neutral particle with a relatively large magnetic dipole moment could fake a dark matter signal. We argue that a very definite flux could explain the signals seen at DAMA/LIBRA, CDMS/Si and CoGeNT consistently with the bounds from XENON100 and CDMS/Ge. To explore the plausibility of this scenario, we discuss a concrete model with 10-50 MeV sterile neutrinos that was recently proposed to explain the LSND and MiniBooNE anomalies.
Optical emission spectroscopy of atmospheric pressure microwave plasmas
Jia Haijun; Fujiwara, Hiroyuki; Kondo, Michio [Research Center for Photovoltaics (RCPVs), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Kuraseko, Hiroshi [Furukawa Electric Co., Ltd., Production Technology Development Center, 6 Yawata-Kaigandori, Chiba 290-8555 (Japan)
2008-09-01T23:59:59.000Z
The optical emission behaviors of Ar, He, and Ar+He plasmas generated in air using an atmospheric pressure microwave plasma source have been studied employing optical emission spectroscopy (OES). Emissions from various source gas species and air were observed. The variations in the intensities and intensity ratios of specific emissions as functions of the microwave power and gas flow rate were analyzed to investigate the relationship between the emission behavior and the plasma properties. We find that dependence of the emission behavior on the input microwave power is mainly determined by variations in electron density and electron temperature in the plasmas. On the other hand, under different gas flow rate conditions, changes in the density of the source gas atoms also significantly affect the emissions. Interestingly, when plasma is generated using an Ar+He mixture, emissions from excited He atoms disappear while a strong H{sub {alpha}} signal appears. The physics behind these behaviors is discussed in detail.
Controlled Microdroplet Transport in an Atmospheric Pressure Microplasma
Maguire, P D; Kelsey, C P; Bingham, A; Montgomery, E P; Bennet, E D; Potts, H E; Rutherford, D; McDowell, D A; Diver, D A; Mariotti, D
2015-01-01T23:59:59.000Z
We report the controlled injection of near-isolated micron-sized liquid droplets into a low temperature He-Ne steady-state rf plasma at atmospheric pressure. The H2O droplet stream is constrained within a 2 mm diameter quartz tube. Imaging at the tube exit indicates a log-normal droplet size distribution with an initial count mean diameter of 15 micrometers falling to 13 micrometers with plasma exposure. The radial velocity profile is approximately parabolic indicating near laminar flow conditions with the majority of droplets travelling at >75% of the local gas speed and having a plasma transit time of < 100 microseconds. The maximum gas temperature, determined from nitrogen spectral lines, was below 400 K and the observed droplet size reduction implies additional factors beyond standard evaporation, including charge and surface chemistry effects. The successful demonstration of controlled microdroplet streams opens up possibilities for gas-phase microreactors and remote delivery of active species for pla...
Phenomena of oscillations in atmospheric pressure direct current glow discharges
Liu, Fu-cheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Yan, Wen; Wang, De-zhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)
2013-12-15T23:59:59.000Z
Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transform spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.
Millimeter Wavelength Brightness Fluctuations of the Atmosphere Above the South Pole
R. S. Bussmann; W. L. Holzapfel; C. L. Kuo
2004-12-02T23:59:59.000Z
We report measurements of the millimeter wavelength brightness fluctuations produced by the atmosphere above the South Pole made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR). The data span the 2002 Austral winter during which ACBAR was mounted on the Viper telescope at the South Pole. We recover the atmospheric signal in the presence of instrument noise by calculating the correlation between signals from distinct elements of the ACBAR bolometer array. With this method, it is possible to measure atmospheric brightness fluctuations with high SNR even under the most stable atmospheric conditions. The observed atmospheric signal is characterized by the parameters of the Komolgorov-Taylor (KT) model, which are the amplitude and power law exponent describing the atmospheric power spectrum, and the two components of the wind angular velocity at the time of the observation. The KT model is typically a good description of the observed fluctuations, and fits to the data produce values of the Komolgorov exponent that are consistent with theoretical expectations. By combining the wind angular velocity results with measurements of the wind linear velocity, we find that the altitude of the observed atmospheric fluctuations is consistent with the distribution of water vapor determined from radiosonde data. For data corresponding to frequency passbands centered on 150, 219, and 274 GHz, we obtain median fluctuation power amplitudes of [10, 38, 74] mK^{2} rad^{-5/3} in Rayleigh-Jeans temperature units. Comparing with previous work, we find that these median amplitudes are approximately an order of magnitude smaller than those found at the South Pole during the Austral summer and at least 30 times lower than found at the ALMA site in the Atacama desert.
TTProblem A Air Conditioning Machinery
California at Berkeley, University of
TTProblem A Air Conditioning Machinery Input file: ducts.in You are a technician for the Air Conditioning Machinery company (ACM). Unfortunately, when you arrive at a customer site to install some air conditioning ducts, you discover that you are running low on supplies. You have only six duct segments
Energy conditions and their implications
Visser, Matt
Energy conditions and their implications Matt Visser Physics Department Washington University Saint;#16;s (Los Alamos) Midwest Relativity 9 November 1999. #12; Abstract: The energy conditions of general- itational #12;elds and cosmological geometries. However, the energy conditions are beginning to look a lot
A Community Atmosphere Model with Superparameterized Clouds
Randall, David; Branson, Mark; Wang, Minghuai; Ghan, Steven J.; Craig, Cheryl; Gettelman, A.; Edwards, Jim
2013-06-18T23:59:59.000Z
In 1999, National Center for Atmospheric Research (NCAR) scientists Wojciech Grabowski and Piotr Smolarkiewicz created a "multiscale" atmospheric model in which the physical processes associated with clouds were represented by running a simple high-resolution model within each grid column of a lowresolution global model. In idealized experiments, they found that the multiscale model produced promising simulations of organized tropical convection, which other models had struggled to produce. Inspired by their results, Colorado State University (CSU) scientists Marat Khairoutdinov and David Randall created a multiscale version of the Community Atmosphere Model (CAM). They removed the cloud parameterizations of the CAM, and replaced them with Khairoutdinov's high-resolution cloud model. They dubbed the embedded cloud model a "super-parameterization," and the modified CAM is now called the "SP-CAM." Over the next several years, many scientists, from many institutions, have explored the ability of the SP-CAM to simulate tropical weather systems, the day-night changes of precipitation, the Asian and African monsoons, and a number of other climate processes. Cristiana Stan of the Center for Ocean-Land-Atmosphere Interactions found that the SP-CAM gives improved results when coupled to an ocean model, and follow-on studies have explored the SP-CAM's utility when used as the atmospheric component of the Community Earth System Model. Much of this research has been performed under the auspices of the Center for Multiscale Modeling of Atmospheric Processes, a National Science Foundation (NSF) Science and Technology Center for which the lead institution is CSU.
Michael Joyce; Bruno Marcos; Thierry Baertschiger
2008-11-26T23:59:59.000Z
The effects of discreteness arising from the use of the N-body method on the accuracy of simulations of cosmological structure formation are not currently well understood. After a discussion of how the relevant discretisation parameters introduced should be extrapolated to recover the Vlasov-Poisson limit, we study numerically, and with analytical methods we have developed recently, the central issue of how finite particle density affects the precision of results. In particular we focus on the power spectrum at wavenumbers around and above the Nyquist wavenumber, in simulations in which the force resolution is taken smaller than the initial interparticle spacing. Using simulations of identical theoretical initial conditions sampled on four different "pre-initial" configurations (three different Bravais lattices, and a glass) we obtain a {\\it lower bound} on the real discreteness error. With the guidance of our analytical results, we establish with confidence that the measured dispersion is not contaminated either by finite box size effects or by subtle numerical effects. Our results show notably that, at wavenumbers {\\it below} the Nyquist wavenumber, the dispersion increases monotonically in time throughout the simulation, while the same is true above the Nyquist wavenumber once non-linearity sets in. For normalizations typical of cosmological simulations, we find lower bounds on errors at the Nyquist wavenumber of order of a percent, and larger above this scale. The only way this error may be reduced below these levels at these scales, and indeed convergence to the physical limit firmly established, is by extrapolation, at fixed values of the other relevant parameters, to the regime in which the mean comoving interparticle distance becomes less than the force smoothing scale.
Controlled atmosphere for fabrication of cermet electrodes
Ray, Siba P. (Murrysville, PA); Woods, Robert W. (New Kensington, PA)
1998-01-01T23:59:59.000Z
A process for making an inert electrode composite wherein a metal oxide and a metal are reacted in a gaseous atmosphere at an elevated temperature of at least about 750.degree. C. The metal oxide is at least one of the nickel, iron, tin, zinc and zirconium oxides and the metal is copper, silver, a mixture of copper and silver or a copper-silver alloy. The gaseous atmosphere has an oxygen content that is controlled at about 5-3000 ppm in order to obtain a desired composition in the resulting composite.
Controlled atmosphere for fabrication of cermet electrodes
Ray, S.P.; Woods, R.W.
1998-08-11T23:59:59.000Z
A process is disclosed for making an inert electrode composite wherein a metal oxide and a metal are reacted in a gaseous atmosphere at an elevated temperature of at least about 750 C. The metal oxide is at least one of the nickel, iron, tin, zinc and zirconium oxides and the metal is copper, silver, a mixture of copper and silver or a copper-silver alloy. The gaseous atmosphere has an oxygen content that is controlled at about 5--3000 ppm in order to obtain a desired composition in the resulting composite. 2 figs.
Measuring Atmospheric Neutrino Oscillations with Neutrino Telescopes
Ivone F. M. Albuquerque; George F. Smoot
2001-03-28T23:59:59.000Z
Neutrino telescopes with large detection volumes can demonstrate that the current indications of neutrino oscillation are correct or if a better description can be achieved with non-standard alternatives. Observations of contained muons produced by atmospheric neutrinos can better constrain the allowed region for oscillations or determine the relevant parameters of non-standard models. We analyze the possibility of neutrino telescopes measuring atmospheric neutrino oscillations. We suggest adjustments to improve this potential. An addition of four densely-instrumented strings to the AMANDA II detector makes observations feasible. Such a configuration is competitive with current and proposed experiments.
DOCTORAL TRAINING GRANT (DTG) SCHEME TERMS AND CONDITIONS A Doctoral Training Grant (DTG. Doctoral Training Grants aim to: · assist the Research Organisation to attract the best people into postgraduate research and training; · allow a maximum of local discretion in managing and organising doctoral
Tangler, J; Smith, B; Jager, D; Olsen, T
1990-09-01T23:59:59.000Z
The Solar Energy Research Institute (SERI), in cooperation with SeaWest Energy Group, has completed extensive atmospheric testing of the special-purpose SERI thin-airfoil family during the 1990 wind season. The purpose of this test program was to experimentally verify the predicted performance characteristics of the thin-airfoil family on a geometrically optimized blade, and to compare it to original-equipment blades under atmospheric wind conditions. The tests were run on two identical Micon 65/13 horizontal-axis wind turbines installed side-by-side in a wind farm. The thin-airfoil family 7.96 m blades were installed on one turbine, and AeroStar 7.41 m blades were installed on the other. This paper presents final performance results of the side-by-side comparative field test for both clean and dirty blade conditions. 7 refs., 11 figs., 1 tab.
LECTURES ON GLAUBER DYNAMICS FOR DISCRETE SPIN MODELS
Transitions 5.1 The SolidonSolid Approximation 5.2 Back to the Ising Model 5.3 Recent Progresses 6. Phase Measures 2.3 Weak and Strong Mixing Conditions 2.4 Mixing properties and bounds on relative densities 3 on the Spectral Gap with Free B.C 6.6 Mixed B.C 6.7 Applications 7. Glauber Dynamics for the Dilute Ising Model 7
The mean molecular mass of Titan's atmosphere
Withers, Paul
, Mars, Mars #12;Science Questions · Mean molecular mass (µ) -> Chemical composition · How did Titan form? · Current reservoirs of volatiles · Ethane/methane puddles/ocean · Thermal structure of atmosphere #12, delicate, etc T/p sensors are simple, cheap, reliable · Is it possible to know µ based on simple
Characterizing Titan's Upper Atmosphere Using the Titan
Johnson, Robert E.
methane chemical losses. INMS Data T-GITM Bell et al. [2010b] #12;Constraints on Escape · Parameter Sweep-Thermosphere Model (GITM) · 3-D, non-hydrostatic, altitude-based atmospheric model Compressible Navier (TVD) MUSCL Scheme. Block-based Massively Parallel Framework Updating with 4th order Runge
Connectivity To Atmospheric Release Advisory Capability
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2001-02-26T23:59:59.000Z
To establish DOE and NNSA connectivity to Atmospheric Release Advisory Capability (ARAC) for sites and facilities that have the potential for releasing hazardous materials sufficient to generate certain emergency declarations and to promote efficient use of resources for consequence assessment activities at DOE sites, facilities, operations, and activities in planning for and responding to emergency events. No cancellations.
Atmospheric dispersion in mountain valleys and basins
Allwine, K.J.
1992-01-01T23:59:59.000Z
The primary goal of the research is to further characterize and understand dispersion in valley and basin atmospheres. A secondary, and related goal, is to identify and understand the dominant physical processes governing this dispersion. This has been accomplished through a review of the current literature, and analyses of recently collected data from two field experiments. This work should contribute to an improved understanding of material transport in the atmospheric boundary layer. It was found that dispersion in a freely draining valley (Brush Creek valley, CO) atmosphere is much greater than in an enclosed basin (Roanoke, VA) atmosphere primarily because of the greater wind speeds moving past the release point and the greater turbulence levels. The development of a cold air pool in the Roanoke basin is the dominant process governing nighttime dispersion in the basin, while the nighttime dispersion in the Brush Creek valley is dominated by turbulent diffusion and plume confinement between the valley sidewalls. The interaction between valley flows and above ridgetops flows is investigated. A ventilation rate'' of material transport between the valley and above ridgetop flows is determined. This is important in regional air pollution modeling and global climate modeling. A simple model of dispersion in valleys, applicable through a diurnal cycle, is proposed.
Atmospheric dispersion in mountain valleys and basins
Allwine, K.J.
1992-01-01T23:59:59.000Z
The primary goal of the research is to further characterize and understand dispersion in valley and basin atmospheres. A secondary, and related goal, is to identify and understand the dominant physical processes governing this dispersion. This has been accomplished through a review of the current literature, and analyses of recently collected data from two field experiments. This work should contribute to an improved understanding of material transport in the atmospheric boundary layer. It was found that dispersion in a freely draining valley (Brush Creek valley, CO) atmosphere is much greater than in an enclosed basin (Roanoke, VA) atmosphere primarily because of the greater wind speeds moving past the release point and the greater turbulence levels. The development of a cold air pool in the Roanoke basin is the dominant process governing nighttime dispersion in the basin, while the nighttime dispersion in the Brush Creek valley is dominated by turbulent diffusion and plume confinement between the valley sidewalls. The interaction between valley flows and above ridgetops flows is investigated. A ``ventilation rate`` of material transport between the valley and above ridgetop flows is determined. This is important in regional air pollution modeling and global climate modeling. A simple model of dispersion in valleys, applicable through a diurnal cycle, is proposed.
Exploring the Deep... Ocean-Atmosphere
Wright, Dawn Jeannine
Climate oscillations 97 #12;Storing energy To understand how solar radiation affects large-scale processes amount. This resistance to change is called thermal inertia. However, even small changes to the energy), and biosphere (living organisms) that are driven by solar energy. The ocean and the atmosphere have the greatest
Microlensing Effects in Atmospheres of Substars
L. A. Berdina; A. A. Minakov
2007-12-10T23:59:59.000Z
The purpose of the present work is the study of focusing properties of atmospheres of substars that is necessary for adequate interpreting of observational data and for solving the inverse problem consisting in recovery parameters of 'microlenses' (substars) and sources (quasars). Amplification factor for a quasar image as projected onto the field of microlenses-substars was computed for optical and radio wavelengths.
Adaptive control for Mars atmospheric flight
Restrepo, Carolina Isabel
2009-05-15T23:59:59.000Z
. . . . 49 a. Effects of Uncertainty in Atmospheric Density and Aerodynamic Coefficients . . . . . . . . . . . 49 b. Effects of Uncertainty in the Vehicle Inertias . . . 51 ix CHAPTER Page c. Effects of Uncertainties in Density, Aerody- namic Coefficients... . . . . . . . . . . . . . . . . . . . . . . 13 IV Ellipsled Aerodynamics . . . . . . . . . . . . . . . . . . . . . . . . . 14 V Maximum Control Input . . . . . . . . . . . . . . . . . . . . . . . . . 40 xi LIST OF FIGURES FIGURE Page 1 Ellipsled Entry Trajectory [1...
Ocean Atmosphere Sea Ice Soil User's Guide
OASIS3 Ocean Atmosphere Sea Ice Soil User's Guide oasis3 prism 22, June 2004 Sophie Valcke 1 to realize a coupled simulation with OASIS3. The aim of OASIS3 is to provide a flexible and user friendly. OASIS3 synchronizes the exchanges of coupling fields between the models being coupled, and performs 2D
Ocean Atmosphere Sea Ice Soil User's Guide
OASIS3 Ocean Atmosphere Sea Ice Soil User's Guide oasis3 prism 23, August 2004 Sophie Valcke 1 to realize a coupled simulation with OASIS3. The aim of OASIS3 is to provide a flexible and user friendly. OASIS3 synchronizes the exchanges of coupling fields between the models being coupled, and performs 2D
Ocean Atmosphere Sea Ice Soil User's Guide
OASIS 2.0 Ocean Atmosphere Sea Ice Soil User's Guide and Reference Manual November 1995 Laurent for the straightforward use of OASIS 2.0. As far as we know, it is the best way to use it! The aim of OASIS is to provide been particularly emphasized in the OASIS design. The use of OASIS does not change the way the models
Modeling of Alpine Atmospheric Dynamics II
Gohm, Alexander
Modeling of Alpine Atmospheric Dynamics II 707.424, VU 2, SS2005 Unit 7: Model code structure: mesoscale convective system 17-18 April 2004: Sierra hydraulic jump case 21 January 2005: the "Universiade) Introduction (brief description of the phenomenon and a description of the model and of the measurements
Ch.6 Atmospheric and Oceanic Circulations
Pan, Feifei
;Learning Objective Four: Driving forces of wind #12;Driving Forces within the Atmosphere Gravity Pressure Gradient Force Coriolis Force Friction Force #12;Isobar and contour line Isobar---equal pressure Contour line--equal elevation Contour lines Terrain #12;Pressure Gradient Force The pressure
THE LOWER SOLAR ATMOSPHERE ROBERT J. RUTTEN
Rutten, Rob
over large fields, long times and many wave- lengths (heights) simultaneously -- Judge and Peter (1998THE LOWER SOLAR ATMOSPHERE ROBERT J. RUTTEN Sterrekundig Instituut, Postbus 80 000, NLÂ3508 TA, Utrecht, The Netherlands Abstract. This "rapporteur" report discusses the solar photosphere and low
Air Resources Laboratory Atmospheric Tracer Technology
The continuous (near real time) sulfur hexafluoride (SF6 ) analyzers are portable systems that make measurements of atmospheric SF6 concentrations with a response time of just under one second. The rapid response time in Gaussian plume transport and dispersion models. The SF6 analyzers include a computer controlled calibration
Atmospheric Chemistry, Modeling, and Biogeochemistry of Mercury
activities that release mercury to the atmosphere include coal burning, industrial processes, waste incine and climate projections; critically and quantitatively analyze environmental management and policy proposals mercury research. Global Budget of Mercury Prior to the onset of human industrial activities, the amount
Introducing Research College of Oceanic & Atmospheric Sciences
Barth, Jack
WECOMA Coll ege of Oceanic & Atmospheric Scie nces OREGON STATE UNIVERSITY in the O cean currents introduced by man (e.g., pollutants). Knowledge of upper-ocean currents is important for navigation and for search and rescue. The ocean currents off Oregon vary seasonally and can also vary from year to year
Introducing Research College of Oceanic & Atmospheric Sciences
Pierce, Stephen
.coas.oregonstate.edu WECOMA WECOMA Coll ege of Oceanic & Atmospheric Scie nces OREGON STATE UNIVERSITY in the O cean currents, to the south in summer and generally to the north in winter, create ocean currents. The strong summertime and the topography of the ocean floor influence the east-west cross-shelf currents. Understanding and being able
Quantifying chaos in the atmosphere Richard Washington
Washington, Richard
, Mansfield Road, Oxford OX1 3TB, UK Abstract: The atmosphere is known to be forced by a variety of energy sources, including radiation and heat fluxes emanating from the boundary layer associated with sea as the competing champions controlling process in the physical world. With or without Einstein, there can
Processing materials inside an atmospheric-pressure radiofrequency nonthermal plasma discharge
Selwyn, Gary S.; Henins, Ivars; Park, Jaeyoung; Herrmann, Hans W.
2006-04-11T23:59:59.000Z
Apparatus for the processing of materials involving placing a material either placed between an radio-frequency electrode and a ground electrode, or which is itself one of the electrodes. This is done in atmospheric pressure conditions. The apparatus effectively etches or cleans substrates, such as silicon wafers, or provides cleaning of spools and drums, and uses a gas containing an inert gas and a chemically reactive gas.
Factors affecting the performance of a codisposal atmospheric fluidized-bed combustor
Huang, W.C.
1982-01-01T23:59:59.000Z
The paper describes the operation of the codisposal atmospheric fluidized-bed combustor (AFBC) installed at Duluth, Minnesota. The facility utilizes refuse-derived fuel to codispose sewage sludge without auxiliary fuel. Operating parameters affecting the combustor performance are discussed with emphasis on temperature distribution, bed fluidization, residence time, freeboard height and flyash properties. Optimum operating conditions are presented and some new concepts and trends of future development in fluidized bed technology are touched on.
Quantization of systems with temporally varying discretization I: Evolving Hilbert spaces
Philipp A. Hoehn
2014-10-02T23:59:59.000Z
A temporally varying discretization often features in discrete gravitational systems and appears in lattice field theory models subject to a coarse graining or refining dynamics. To better understand such discretization changing dynamics in the quantum theory, an according formalism for constrained variational discrete systems is constructed. While the present manuscript focuses on global evolution moves and, for simplicity, restricts to Euclidean configuration spaces, a companion article discusses local evolution moves. In order to link the covariant and canonical picture, the dynamics of the quantum states is generated by propagators which satisfy the canonical constraints and are constructed using the action and group averaging projectors. This projector formalism offers a systematic method for tracing and regularizing divergences in the resulting state sums. Non-trivial coarse graining evolution moves lead to non-unitary, and thus irreversible, projections of physical Hilbert spaces and Dirac observables such that these concepts become evolution move dependent on temporally varying discretizations. The formalism is illustrated in a toy model mimicking a `creation from nothing'. Subtleties arising when applying such a formalism to quantum gravity models are discussed.
Classification of constraints and degrees of freedom for quadratic discrete actions
Philipp A. Hoehn
2014-11-13T23:59:59.000Z
We provide a comprehensive classification of constraints and degrees of freedom for variational discrete systems governed by quadratic actions. This classification is based on the different types of null vectors of the Lagrangian two-form and employs the canonical formalism developed in arXiv:1303.4294 [math-ph] (J. Math. Phys. 54, 093505 (2013)) and arXiv:1401.6062 [gr-qc] (J. Math. Phys. 55, 083508 (2014)). The analysis is carried out in both the classical and quantum theory and applies to systems with both temporally varying or constant discretization. In particular, it is shown explicitly how changes in the discretization, e.g. resulting from canonical coarse graining or refining operations or an evolving background geometry, change the dynamical content of the system. It is demonstrated how, on a temporally varying discretization, constraints, Dirac observables, symmetries, reduced phase spaces and physical Hilbert spaces become spacetime region dependent. These results are relevant for free field theory on an evolving lattice and linearized discrete gravity models.
Kitzmann, D; Rauer, H
2013-01-01T23:59:59.000Z
Owing to their wavelengths dependent absorption and scattering properties, clouds have a strong impact on the climate of planetary atmospheres. Especially, the potential greenhouse effect of CO2 ice clouds in the atmospheres of terrestrial extrasolar planets is of particular interest because it might influence the position and thus the extension of the outer boundary of the classic habitable zone around main sequence stars. We study the radiative effects of CO2 ice particles obtained by different numerical treatments to solve the radiative transfer equation. The comparison between the results of a high-order discrete ordinate method and simpler two-stream approaches reveals large deviations in terms of a potential scattering efficiency of the greenhouse effect. The two-stream methods overestimate the transmitted and reflected radiation, thereby yielding a higher scattering greenhouse effect. For the particular case of a cool M-type dwarf the CO2 ice particles show no strong effective scattering greenhouse eff...
Impact of surface inhomogeneity on solar radiative transfer under overcast conditions
Li, Zhanqing
Impact of surface inhomogeneity on solar radiative transfer under overcast conditions Zhanqing Li1. Introduction [2] Solar radiative heating is the primary driving force of atmospheric and oceanic movements underlines the impact of surface inhomogeneity on the closure of SW radiative transfer. It also leads
Jan L. Cie?li?ski; Anatolij K. Prykarpatski
2014-03-27T23:59:59.000Z
We investigate discretizations of the integrable discrete nonlinear Schr\\"odinger dynamical system and related symplectic structures. We develop an effective scheme of invariant reducing the corresponding infinite system of ordinary differential equations to an equivalent finite system of ordinary differential equations with respect to the evolution parameter. We construct a finite set of recurrent algebraic regular relations allowing to generate solutions of the discrete nonlinear Schr\\"odinger dynamical system and we discuss the related functional spaces of solutions. Finally, we discuss the Fourier transform approach to studying the solution set of the discrete nonlinear Schr\\"odinger dynamical system and its functional-analytical aspects.
Honda, M.; Kajita, T.; Kasahara, K.; Midorikawa, S.; Sanuki, T
2007-02-15T23:59:59.000Z
Using the 'modified DPMJET-III' model explained in the previous paper [T. Sanuki et al., preceding Article, Phys. Rev. D 75, 043005 (2007).], we calculate the atmospheric neutrino flux. The calculation scheme is almost the same as HKKM04 [M. Honda, T. Kajita, K. Kasahara, and S. Midorikawa, Phys. Rev. D 70, 043008 (2004).], but the usage of the 'virtual detector' is improved to reduce the error due to it. Then we study the uncertainty of the calculated atmospheric neutrino flux summarizing the uncertainties of individual components of the simulation. The uncertainty of K-production in the interaction model is estimated using other interaction models: FLUKA'97 and FRITIOF 7.02, and modifying them so that they also reproduce the atmospheric muon flux data correctly. The uncertainties of the flux ratio and zenith angle dependence of the atmospheric neutrino flux are also studied.
Conditional entropy of ordinal patterns
Anton M. Unakafov; Karsten Keller
2014-07-21T23:59:59.000Z
In this paper we investigate a quantity called conditional entropy of ordinal patterns, akin to the permutation entropy. The conditional entropy of ordinal patterns describes the average diversity of the ordinal patterns succeeding a given ordinal pattern. We observe that this quantity provides a good estimation of the Kolmogorov-Sinai entropy in many cases. In particular, the conditional entropy of ordinal patterns of a finite order coincides with the Kolmogorov-Sinai entropy for periodic dynamics and for Markov shifts over a binary alphabet. Finally, the conditional entropy of ordinal patterns is computationally simple and thus can be well applied to real-world data.
Staggered grids discretization in three-dimensional Darcy convection
B. Karasozen; A. D. Nemtsev; V. G. Tsybulin
2008-02-17T23:59:59.000Z
We consider three-dimensional convection of an incompressible fluid saturated in a parallelepiped with a porous medium. A mimetic finite-difference scheme for the Darcy convection problem in the primitive variables is developed. It consists of staggered nonuniform grids with five types of nodes, differencing and averaging operators on a two-nodes stencil. The nonlinear terms are approximated using special schemes. Two problems with different boundary conditions are considered to study scenarios of instability of the state of rest. Branching off of a continuous family of steady states was detected for the problem with zero heat fluxes on two opposite lateral planes.
Comparison of discrete and continuous thermal neutron scattering treatments in MCNP5
Pavlou, A. T. [Univ. of Michigan, Dept. of Nuclear Engineering and Radiological Sciences, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Brown, F. B. [Los Alamos National Laboratory, Monte Carlo Codes Group, MS A143, PO Box 1663, Los Alamos, NM 87545 (United States); Martin, W. R. [Univ. of Michigan, Dept. of Nuclear Engineering and Radiological Sciences, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Kiedrowski, B. C. [Los Alamos National Laboratory, Monte Carlo Codes Group, MS A143, PO Box 1663, Los Alamos, NM 87545 (United States)
2012-07-01T23:59:59.000Z
The standard discrete thermal neutron S({alpha},{beta}) scattering treatment in MCNP5 is compared with a continuous S({alpha},{beta}) scattering treatment using a criticality suite of 119 benchmark cases and ENDF/B-VII.0 nuclear data. In the analysis, six bound isotopes are considered: beryllium metal, graphite, hydrogen in water, hydrogen in polyethylene, beryllium in beryllium oxide and oxygen in beryllium oxide. Overall, there are only small changes in the eigenvalue (k{sub eff}) between discrete and continuous treatments. In the comparison of 64 cases that utilize S({alpha},{beta}) scattering, 62 agreed at the 95% confidence level, and the 2 cases with differences larger than 3 {sigma} agreed within 1 {sigma} when more neutrons were run in the calculations. The results indicate that the changes in eigenvalue between continuous and discrete treatments are random, small, and well within the uncertainty of measured data for reactor criticality experiments. (authors)
Discrete-time Lyapunov design for neuroadaptive control of elastic-joint robots
Macnab, C.J.B.; D'Eleuterio, G.M.T.
2000-05-01T23:59:59.000Z
A neural-network controller operating in discrete time is shown to result in stable trajectory tracking for rigid and elastic-joint robots. The technique assumes continuous-time state feedback. The proof of stability uses discrete-time Lyapunov functions. For the elastic-joint case, a discrete-time version of the adaptive backstepping technique is used. The result is that the neural network can be run at a very slow control rate, suitable for online calculations. The neural network used is referred to as the CMAC-RBF Associative Memory (CRAM), a modification of Albus's Cerebellar Model Arithmetic Computer (CMAC) algorithm using radial basis functions (RBFs). Simulation results are provided for a two-link planar elastic-joint robot and show that performance can be improved by using a larger network at a slower control rate.
Correction terms for propagators and d'Alembertians due to spacetime discreteness
Steven Johnston
2014-11-10T23:59:59.000Z
The causal set approach to quantum gravity models spacetime as a discrete structure - a causal set. Recent research has led to causal set models for the retarded propagator for the Klein-Gordon equation and the d'Alembertian operator. These models can be compared to their continuum counterparts via a sprinkling process. It has been shown that the models agree exactly with the continuum quantities in the limit of an infinite sprinkling density - the continuum limit. This paper obtains the correction terms for these models for sprinkled causal sets with a finite sprinkling density. These correction terms are an important step towards testable differences between the continuum and discrete models that could provide evidence of spacetime discreteness.
Discrete Self-Similarity Of RR Lyrae Stars II. Period Spectrum For A Very Large Sample
R. L. Oldershaw
2006-06-06T23:59:59.000Z
A recent paper demonstrated a considerable degree of self-similarity between RR Lyrae stars and their atomic scale analogues: excited helium atoms undergoing single-level transition between n = 7 and n = 10. Discrete self-similarity between these fractal analogues was indentified in terms of their masses, radii, oscillation periods, basic morphologies and kinematics. In this second paper on the subject, an extremely large and carefully analyzed sample of RR Lyrae oscillation periods provides further evidence for a unique match between the predicted set of discrete periods, based exclusively on the known helium spectrum and the discrete scaling equations of a fractal cosmological paradigm, and the observed period spectra of RR Lyrae stars.