National Library of Energy BETA

Sample records for macroeconomic feedback mechanism

  1. Analyzing Fuel Saving Opportunities through Driver Feedback Mechanisms...

    Office of Environmental Management (EM)

    Analyzing Fuel Saving Opportunities through Driver Feedback Mechanisms Analyzing Fuel Saving Opportunities through Driver Feedback Mechanisms 2011 DOE Hydrogen and Fuel Cells...

  2. Obtaining Reliable Feedback for Sanctioning Reputation Mechanisms

    E-Print Network [OSTI]

    Faltings, B; 10.1613/jair.2243

    2011-01-01

    Reputation mechanisms offer an effective alternative to verification authorities for building trust in electronic markets with moral hazard. Future clients guide their business decisions by considering the feedback from past transactions; if truthfully exposed, cheating behavior is sanctioned and thus becomes irrational. It therefore becomes important to ensure that rational clients have the right incentives to report honestly. As an alternative to side-payment schemes that explicitly reward truthful reports, we show that honesty can emerge as a rational behavior when clients have a repeated presence in the market. To this end we describe a mechanism that supports an equilibrium where truthful feedback is obtained. Then we characterize the set of pareto-optimal equilibria of the mechanism, and derive an upper bound on the percentage of false reports that can be recorded by the mechanism. An important role in the existence of this bound is played by the fact that rational clients can establish a reputation for...

  3. Truthful Feedback for Sanctioning Reputation Mechanisms

    E-Print Network [OSTI]

    Witkowski, Jens

    2012-01-01

    For product rating environments, similar to that of Amazon Reviews, it has been shown that the truthful elicitation of feedback is possible through mechanisms which pay buyer reports contingent on the reports of other buyers. We study whether similar mechanisms can be designed for reputation mechanisms at online auction sites where the buyers' experiences are partially determined by a strategic seller. We show that this is impossible for the basic setting. However, introducing a small prior belief that the seller is a cooperative commitment player leads to a payment scheme with a truthful perfect Bayesian equilibrium.

  4. Truthful Feedback for Sanctioning Reputation Mechanisms Jens Witkowski

    E-Print Network [OSTI]

    Nebel, Bernhard

    Truthful Feedback for Sanctioning Reputation Mechanisms Jens Witkowski Department of ComputerBay. These mechanisms are called sanctioning as they induce cooperation of the auction sellers through a threat to sanction uncooperative behavior. The es- sential distinction between these two roles of reputa- tion

  5. Feedback mechanism for smart nozzles and nebulizers

    DOE Patents [OSTI]

    Montaser, Akbar [Potomac, MD; Jorabchi, Kaveh [Arlington, VA; Kahen, Kaveh [Kleinburg, CA

    2009-01-27

    Nozzles and nebulizers able to produce aerosol with optimum and reproducible quality based on feedback information obtained using laser imaging techniques. Two laser-based imaging techniques based on particle image velocimetry (PTV) and optical patternation map and contrast size and velocity distributions for indirect and direct pneumatic nebulizations in plasma spectrometry. Two pulses from thin laser sheet with known time difference illuminate droplets flow field. Charge coupled device (CCL)) captures scattering of laser light from droplets, providing two instantaneous particle images. Pointwise cross-correlation of corresponding images yields two-dimensional velocity map of aerosol velocity field. For droplet size distribution studies, solution is doped with fluorescent dye and both laser induced florescence (LIF) and Mie scattering images are captured simultaneously by two CCDs with the same field of view. Ratio of LIF/Mie images provides relative droplet size information, then scaled by point calibration method via phase Doppler particle analyzer.

  6. Macroeconomics: A Survey of Laboratory Research Department of Economics

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    to laboratory experiments involving human subjects but rather to computational experiments using calibrated Welcome Abstract This chapter surveys laboratory experiments addressing macroeconomic phenomena. The first and mechanisms for resolving these problems. Part three looks at experiments in specific macroeconomic sectors

  7. Feedback Mechanism for Microtubule Length Regulation by Stathmin Gradients

    E-Print Network [OSTI]

    Maria Zeitz; Jan Kierfeld

    2014-12-09

    We formulate and analyze a theoretical model for the regulation of microtubule (MT) polymerization dynamics by the signaling proteins Rac1 and stathmin. In cells, the MT growth rate is inhibited by cytosolic stathmin, which, in turn, is inactivated by Rac1. Growing MTs activate Rac1 at the cell edge, which closes a positive feedback loop. We investigate both tubulin sequestering and catastrophe promotion as mechanisms for MT growth inhibition by stathmin. For a homogeneous stathmin concentration in the absence of Rac1, we find a switch-like regulation of the MT mean length by stathmin. For constitutively active Rac1 at the cell edge, stathmin is deactivated locally, which establishes a spatial gradient of active stathmin. In this gradient, we find a stationary bimodal MT length distributions for both mechanisms of MT growth inhibition by stathmin. One subpopulation of the bimodal length distribution can be identified with fast growing and long pioneering MTs in the region near the cell edge, which have been observed experimentally. The feedback loop is closed through Rac1 activation by MTs. For tubulin sequestering by stathmin, this establishes a bistable switch with two stable states: one stable state corresponds to upregulated MT mean length and bimodal MT length distributions, i.e., pioneering MTs; the other stable state corresponds to an interrupted feedback with short MTs. Stochastic effects as well as external perturbations can trigger switching events. For catastrophe promoting stathmin we do not find bistability.

  8. Mechanical feedback in the molecular ISM of luminous IR galaxies

    E-Print Network [OSTI]

    A. F. Loenen; M. Spaans; W. A. Baan; R. Meijerink

    2008-08-20

    Aims: Molecular emission lines originating in the nuclei of luminous infra-red galaxies are used to determine the physical properties of the nuclear ISM in these systems. Methods: A large observational database of molecular emission lines is compared with model predictions that include heating by UV and X-ray radiation, mechanical heating, and the effects of cosmic rays. Results: The observed line ratios and model predictions imply a separation of the observedsystems into three groups: XDRs, UV-dominated high-density (n>=10^5 cm-3) PDRs, and lower-density (n=10^4.5 cm-3) PDRs that are dominated by mechanical feedback. Conclusions: The division of the two types of PDRs follows naturally from the evolution of the star formation cycle of these sources, which evolves from deeply embedded young stars, resulting in high-density (n>=10^5 cm-3) PDRs, to a stage where the gas density has decreased (n=10^4.5 cm-3) and mechanical feedback from supernova shocks dominates the heating budget.

  9. Mechanisms of Ventricular Fibrillation The role of mechano-electrical feedback

    E-Print Network [OSTI]

    Utrecht, Universiteit

    Mechanisms of Ventricular Fibrillation The role of mechano-electrical feedback and tissue-90-393-5020-1 #12;Mechanisms of Ventricular Fibrillation The role of mechano-electrical feedback and tissue . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2.1 Mechanisms of Cardiac Arrhythmias . . . . . . . . . . . . . 5 1.2.2 Mechanisms

  10. Reputation, Trust, and Rebates: How Online Auction Markets Can Improve Their Feedback Mechanisms

    E-Print Network [OSTI]

    White, Douglas R.

    Reputation, Trust, and Rebates: How Online Auction Markets Can Improve Their Feedback Mechanisms of it is positive. In this paper, I propose a mechanism whereby sellers can provide rebates to buyers contingent on buyers provision of reports. Using a game theoretical model, I show how the rebate incentive mechanism

  11. Theory and calculations of synchrotron instabilities and feedback-mechanism

    SciTech Connect (OSTI)

    Meijssen, T.E.M.

    1981-08-12

    The properties of the phenomenon synchrotron radiation are given with general theory on the basic processes and betatron and synchrotron oscillations. A more extended theoretical view at transverse instabilities and the influence of a damping feedback system are discussed. The longitudinal case is covered. For the calculations on the longitudinal case with M equally spaced pointbunches, with N electrons each, in the storage ring, the parasitic modes of the radio-frequency cavity were measured. A description of this is given. The values of damping rates of the longitudinal feedback system found, are as expected, but too low to damp the longitudinal instabilities calculated. This might be caused by the input data. The calculated growth rates are very sensitive to changes in frequency and width of the parasitic modes, which were measured under conditions differing slightly from the operating conditions.

  12. Version pressure feedback mechanisms for speculative versioning caches

    DOE Patents [OSTI]

    Eichenberger, Alexandre E.; Gara, Alan; O'Brien, Kathryn M.; Ohmacht, Martin; Zhuang, Xiaotong

    2013-03-12

    Mechanisms are provided for controlling version pressure on a speculative versioning cache. Raw version pressure data is collected based on one or more threads accessing cache lines of the speculative versioning cache. One or more statistical measures of version pressure are generated based on the collected raw version pressure data. A determination is made as to whether one or more modifications to an operation of a data processing system are to be performed based on the one or more statistical measures of version pressure, the one or more modifications affecting version pressure exerted on the speculative versioning cache. An operation of the data processing system is modified based on the one or more determined modifications, in response to a determination that one or more modifications to the operation of the data processing system are to be performed, to affect the version pressure exerted on the speculative versioning cache.

  13. Feedback as a mechanism for the resurrection of oscillations from death state

    E-Print Network [OSTI]

    V. K. Chandrasekar; S. Karthiga; M. Lakshmanan

    2015-07-11

    The quenching of oscillations in interacting systems leads to several unwanted situations, which necessitate a suitable remedy to overcome the quenching. In this connection, this work addresses a mechanism that can resurrect oscillations in a typical situation. Through both numerical and analytical studies, we show the candidate which is capable of resurrecting oscillations is nothing but the feedback, the one which is profoundly used in dynamical control and in bio-therapies. Even in the case of a rather general system, we demonstrate analytically the applicability of the technique over one of the oscillation quenched states called amplitude death state. We also discuss some of the features of this mechanism such as adaptability of the technique with the feedback of only a few of the oscillators.

  14. Essays in open economy macroeconomics

    E-Print Network [OSTI]

    Ghosh, Indradeep, Ph. D. Massachusetts Institute of Technology

    2007-01-01

    This thesis is a collection of two essays on open economy macroeconomics. The first essay is on imperfect asset substitutability and current account dynamics. It is divided into four chapters. The first chapter in this ...

  15. Essays in macroeconomics and experiments

    E-Print Network [OSTI]

    Shurchkov, Olga

    2008-01-01

    This dissertation consists of four chapters on empirical and experimental macroeconomics and other experimental topics. Chapter 1 uses a laboratory experiment to test the predictions of a dynamic global game designed to ...

  16. Macroeconomic Activity Module - NEMS Documentation

    Reports and Publications (EIA)

    2014-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Macroeconomic Activity Module (MAM) used to develop the Annual Energy Outlook for 2014 (AEO2014). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code

  17. Essays on macroeconomic risks and stock prices

    E-Print Network [OSTI]

    Duarte, Fernando Manuel

    2011-01-01

    In this thesis, I study the relationship between macroeconomic risks and asset prices. In the first chapter, I establish that inflation risk is priced in the cross-section of stock returns: stocks that have low returns ...

  18. Essays on political institutions and macroeconomics

    E-Print Network [OSTI]

    Yared, Pierre

    2007-01-01

    This dissertation consists of three chapters on the interaction of political institutions and macroeconomic activity in dynamic environments. Chapter 1 studies the optimal management of taxes and debt in a framework which ...

  19. CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models

    SciTech Connect (OSTI)

    Zhang, Minghua; Bretherton, Christopher S.; Blossey, Peter; Austin, Phillip A.; Bacmeister, J.; Bony, Sandrine; Brient, Florent; Cheedela, Suvarchal K.; Cheng, Anning; Del Genio, Anthony D.; De Roode, Stephan R.; Endo , Satoshi; Franklin, Charmaine N.; Golaz, Jean-Christophe; Hannay, Cecile; Heus, Thijs; Isotta, Francesco A.; Jean-Louis, Dufresne; Kang, In-Sik; Kawai, Hideaki; Koehler, M.; Larson, Vincent E.; Liu, Yangang; Lock, Adrian; Lohmann, U.; Khairoutdinov, Marat; Molod, Andrea M.; Neggers, Roel; Rasch, Philip J.; Sandu, Irina; Senkbeil, Ryan; Siebesma, A. P.; Siegenthaler-Le Drian, Colombe; Stevens, Bjorn; Suarez, Max; Xu, Kuan-Man; Von Salzen, Knut; Webb, Mark; Wolf, Audrey; Zhao, M.

    2013-12-26

    Large Eddy Models (LES) and Single Column Models (SCM) are used in a surrogate climate change 101 to investigate the physical mechanism of low cloud feedbacks in climate models. Enhanced surface-102 driven boundary layer turbulence and shallow convection in a warmer climate are found to be 103 dominant mechanisms in SCMs.

  20. A Java Agent-based MacroEconomic Laboratory

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    A Java Agent-based MacroEconomic Laboratory Pascal Seppecher May 2, 2012 Abstract This paper as a Java application (Jamel: Java Agent-based MacroEconomic Laboratory). This application, together

  1. Short-Term Energy Outlook Model Documentation: Macro Bridge Procedure to Update Regional Macroeconomic Forecasts with National Macroeconomic Forecasts

    Reports and Publications (EIA)

    2010-01-01

    The Regional Short-Term Energy Model (RSTEM) uses macroeconomic variables such as income, employment, industrial production and consumer prices at both the national and regional1 levels as explanatory variables in the generation of the Short-Term Energy Outlook (STEO). This documentation explains how national macroeconomic forecasts are used to update regional macroeconomic forecasts through the RSTEM Macro Bridge procedure.

  2. Macroeconomics and Health: Investing in Health for

    E-Print Network [OSTI]

    Macroeconomics and Health: Investing in Health for Economic Development #12;Information concerning be obtained from: World Health Organization Marketing and Dissemination 1211 Geneva 27, Switzerland tel: (41 clear and strong on the central task of raising the health of the poor. I can be `realistic

  3. Thermal-chemical-mechanical feedback during fluid-rock interactions: Implications for chemical transport and scales of equilibria in the crust

    SciTech Connect (OSTI)

    Dutrow, Barbara

    2008-08-13

    Our research evaluates the hypothesis that feedback amongst thermal-chemical-mechanical processes operative in fluid-rock systems alters the fluid flow dynamics of the system which, in turn, affects chemical transport and temporal and spatial scales of equilibria, thus impacting the resultant mineral textural development of rocks. Our methods include computational experimentation and detailed analyses of fluid-infiltrated rocks from well-characterized terranes. This work focuses on metamorphic rocks and hydrothermal systems where minerals and their textures are utilized to evaluate pressure (P), temperature (T), and time (t) paths in the evolution of mountain belts and ore deposits, and to interpret tectonic events and the timing of these events. Our work on coupled processes also extends to other areas where subsurface flow and transport in porous media have consequences such as oil and gas movement, geothermal system development, transport of contaminants, nuclear waste disposal, and other systems rich in fluid-rock reactions. Fluid-rock systems are widespread in the geologic record. Correctly deciphering the products resulting from such systems is important to interpreting a number of geologic phenomena. These systems are characterized by complex interactions involving time-dependent, non-linear processes in heterogeneous materials. While many of these interactions have been studied in isolation, they are more appropriately analyzed in the context of a system with feedback. When one process impacts another process, time and space scales as well as the overall outcome of the interaction can be dramatically altered. Our goals to test this hypothesis are: to develop and incorporate algorithms into our 3D heat and mass transport code to allow the effects of feedback to be investigated numerically, to analyze fluid infiltrated rocks from a variety of terranes at differing P-T conditions, to identify subtle features of the infiltration of fluids and/or feedback, and to quantify the importance of feedback in complex fluid-rock systems and its affects on time and space scales and rates of reaction. We have made significant contributions toward understanding feedback and its impacts by numerical experimentation using 3D computational modeling of fluid-rock systems and by chemical and textural analyses of fluid-infiltrated rocks.

  4. 14.02 Principles of Macroeconomics, Fall 2002

    E-Print Network [OSTI]

    Schaller, Huntley

    This course will provide an overview of macroeconomic issues: the determination of output, employment, unemployment, interest rates, and inflation. Monetary and fiscal policies are discussed, as are the public debt and ...

  5. 14.02 Principles of Macroeconomics, Fall 2009

    E-Print Network [OSTI]

    Guerrieri, Veronica

    This course is designed to introduce classic macroeconomic issues such as growth, inflation, unemployment, interest rates, exchange rates, technological progress, and budget deficits. The course will provide a unified ...

  6. 14.452 Macroeconomic Theory II, Spring 2005

    E-Print Network [OSTI]

    Blanchard, Olivier (Olivier J.)

    The basic machines of macroeconomics. Ramsey, Solow, Samuelson-Diamond, RBCs, ISLM, Mundell-Fleming, Fischer-Taylor. How they work, what shortcuts they take, and how they can be used. Half-term subject. From the course ...

  7. 14.454 Macroeconomic Theory IV, Fall 2004

    E-Print Network [OSTI]

    Caballero, Ricardo

    This half-term course covers the macroeconomic implications of imperfections in labor markets, goods markets, credit and financial markets. The role of nominal rigidities is also an area of focus.

  8. Asset liability management throughout macroeconomic cycle in financial institutions

    E-Print Network [OSTI]

    Yan, Jingsi

    2013-01-01

    In this thesis, we are going to study asset liability management throughout the macroeconomic cycle in financial institutions. There are two important problems in financial institutions. The first is that asset and liability ...

  9. Essays on informational frictions in macroeconomics and finance

    E-Print Network [OSTI]

    La'O, Jennifer

    2010-01-01

    This dissertation consists of four chapters analyzing the effects of heterogeneous and asymmetric information in macroeconomic and financial settings, with an emphasis on short-run fluctuations. Within these chapters, I ...

  10. Three essays on empirical macroeconomics and financial markets

    E-Print Network [OSTI]

    Chen, Lili

    2012-08-21

    This dissertation consists of three essays on empirical macroeconomics and financial markets in the United States. Although they can be considered as three independent essays, their findings are connected with each other ...

  11. 14.452 Macroeconomic Theory II, Spring 2002

    E-Print Network [OSTI]

    Blanchard, Olivier (Olivier J.)

    The basic machines of macroeconomics. Ramsey, Solow, Samuelson-Diamond, RBCs, ISLM, Mundell-Fleming, Fischer-Taylor. How they work, what shortcuts they take, and how they can be used. Half-term subject. From the course ...

  12. Petroleum Data, Natural Gas Data, Coal Data, Macroeconomic Data, Petroleum Import Data

    SciTech Connect (OSTI)

    2009-01-18

    Supplemental tables to the Annual Energy Outlook (AEO) 2006 for petroleum, natural gas, coal, macroeconomic, and import data

  13. Applications of Time Series in Finance and Macroeconomics 

    E-Print Network [OSTI]

    Ibarra Ramirez, Raul

    2011-08-08

    out-of-sample fore- casts for the in ation rate in Mexico. Factor models are useful to summarize the information contained in large datasets. We evaluate the role of using a wide range of macroeconomic variables to forecast in ation, with particular...-2006 : : : : 42 V Stochastic Dominance Test : : : : : : : : : : : : : : : : : : : : : : : 46 VI Forecasting Results: Headline In ation : : : : : : : : : : : : : : : : : 65 VII Forecasting Results: Core In ation : : : : : : : : : : : : : : : : : : : 66 VIII...

  14. Evolutionary Optimization of Feedback Controllers for Thermoacoustic Instabilities

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Evolutionary Optimization of Feedback Controllers for Thermoacoustic Instabilities Nikolaus Hansen prone to thermoacoustic instabilities which arise due to a feedback loop involving fluctua- tions in acoustic pressure, velocity and heat release. Thermoacoustic instabilities may cause mechanical damage

  15. Self-regulated growth of supermassive black holes by a dual jet/heating AGN feedback mechanism: methods, tests and implications for cosmological simulations

    E-Print Network [OSTI]

    Dubois, Yohan; Slyz, Adrianne; Teyssier, Romain

    2011-01-01

    We develop a new sub-grid model for the growth of supermassive Black Holes (BHs) and their associated Active Galactic Nuclei (AGN) feedback in hydrodynamical cosmological simulations. Assuming that BHs are created in the early stages of galaxy formation, they grow by mergers and accretion of gas at a Eddington-limited Bondi accretion rate. However this growth is regulated by AGN feedback which we model using two different modes: a quasar-heating mode when accretion rates onto the BHs are comparable to the Eddington rate, and a radio-jet mode at lower accretion rates. In other words, our feedback model deposits energy as a succession of thermal bursts and jet outflows depending on the properties of the gas surrounding the BHs. We assess the plausibility of such a model by comparing our results to observational measurements of the coevolution of BHs and their host galaxy properties, and check their robustness with respect to numerical resolution. We show that AGN feedback must be a crucial physical ingredient f...

  16. Applications of Feedback Control in Quantum Systems

    E-Print Network [OSTI]

    Kurt Jacobs

    2006-05-02

    We give an introduction to feedback control in quantum systems, as well as an overview of the variety of applications which have been explored to date. This introductory review is aimed primarily at control theorists unfamiliar with quantum mechanics, but should also be useful to quantum physicists interested in applications of feedback control. We explain how feedback in quantum systems differs from that in traditional classical systems, and how in certain cases the results from modern optimal control theory can be applied directly to quantum systems. In addition to noise reduction and stabilization, an important application of feedback in quantum systems is adaptive measurement, and we discuss the various applications of adaptive measurements. We finish by describing specific examples of the application of feedback control to cooling and state-preparation in nano-electro-mechanical systems and single trapped atoms.

  17. Assumption to the Annual Energy Outlook 2014 - Macroeconomic Activity Module

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (BillionProved Reserves (BillionTechnical InformationDecade Year-0 2Market Module ThisMacroeconomic

  18. Macroeconomic Impacts of the California Global Warming Solutions Act on the

    E-Print Network [OSTI]

    California at Davis, University of

    101 Macroeconomic Impacts of the California Global Warming Solutions Act on the Southern California California Assembly Bill 32 (AB32), the California Global Warming Solutions Act, calls for the cutback

  19. Macroeconomics after the Crisis: Time to Deal with the Pretense-of-Knowledge Syndrome

    E-Print Network [OSTI]

    Caballero, Ricardo J.

    2010-01-01

    The recent financial crisis has damaged the reputation of macroeconomics, largely for its inability to predict the impending financial and economic crisis. To be honest, this inability to predict does not concern me much. ...

  20. The macroeconomic module of the Energy Policy Evaluation Model of Guatemala

    SciTech Connect (OSTI)

    Booth, S.R. (Los Alamos National Lab., NM (USA)); Cancino, R. (Direccion General de Planificacion y Desarrollo Energetico, Guatemala City (Guatemala))

    1991-08-01

    This report describes the methodology and results of the macroeconomic module of the Energy Policy Evaluation Model of Guatemala (MEPEG). This effort was conducted jointly by the Ministry of Energy and Mines of Guatemala and Los Alamos National Laboratory under the Central American Energy and Resources Project of Los Alamos, funded by the US Agency for International Development. The data, theory, empirical specification, and simulation results of the macroeconomic module are described. 10 refs., 2 figs., 6 tabs.

  1. Methodology for the Assessment of the Macroeconomic Impacts of Stricter CAFE Standards - Addendum

    Reports and Publications (EIA)

    2002-01-01

    This assessment of the economic impacts of Corporate Average Fuel Economy (CAFÉ) standards marks the first time the Energy Information Administration has used the new direct linkage of the DRI-WEFA Macroeconomic Model to the National Energy Modeling System (NEMS) in a policy setting. This methodology assures an internally consistent solution between the energy market concepts forecast by NEMS and the aggregate economy as forecast by the DRI-WEFA Macroeconomic Model of the U.S. Economy.

  2. Feedback stabilization initiative

    SciTech Connect (OSTI)

    NONE

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.

  3. Phase Model with Feedback Control for Power Grids

    E-Print Network [OSTI]

    Matsuo, Tatsuma

    2013-01-01

    A phase model with feedback control is studied as a dynamical model of power grids. As an example, we study a model network corresponding to the power grid in the Kyushu region. The standard frequency is maintained by the mutual synchronization and the feedback control. Electric failures are induced by an overload. We propose a local feedback method in which the strength of feedback control is proportional to the magnitude of generators. We find that the electric failures do not occur until the utilization ratio is close to 1 under this feedback control. We also find that the temporal response for the time-varying input power is suppressed under this feedback control. We explain the mechanisms using the corresponding global feedback method.

  4. Global Feedback Simulator

    SciTech Connect (OSTI)

    2015-10-29

    GFS is a simulation engine that is used for the characterization of Accelerator performance parameters based on the machine layout, configuration and noise sources. It combines extensively tested Feedback models with a longitudinal phase space tracking simulator along with the interaction between the two via beam-based feedback using a computationally efficient simulation engine. The models include beam instrumentation, considerations on loop delays for in both the R and beam-based feedback loops, as well as the ability to inject noise (both correlated and uncorrelated) at different points of the machine including a full characterization of the electron gun performance parameters.

  5. Track 10: Feedback and Improvement

    Broader source: Energy.gov [DOE]

    ISM Workshop Presentations Knoxville Convention Center, Knoxville, TN August 2009 Track 10: Feedback and Improvement

  6. Adiabatic feedback control of Hamiltonian systems

    E-Print Network [OSTI]

    A. E. Allahverdyan; K. G. Petrosyan; D. B. Saakian

    2006-07-09

    We study feedback control of classical Hamiltonian systems with the controlling parameter varying slowly in time. The control aims to change system's energy. We show that the control problems can be solved with help of an adiabatic invariant that generalizes the conservation of the phase-space volume to control situations. New mechanisms of control for achieving heating, cooling, entropy reduction and particle trapping are found. The feedback control of a many-body system via one of its coordinates is discussed. The results are illustrated by two basic models of non-linear physics.

  7. Visual Feedback in a Coordinated Hand-Eye System

    E-Print Network [OSTI]

    Woodham, Robert J.

    A system is proposed for the development of new techniques for the control and monitoring of a mechanical arm-hand. The use of visual feedback is seen to provide new interactive capabilities in a machine hand-eye system. ...

  8. Global climate feedbacks

    SciTech Connect (OSTI)

    Manowitz, B.

    1990-10-01

    The important physical, chemical, and biological events that affect global climate change occur on a mesoscale -- requiring high spatial resolution for their analysis. The Department of Energy has formulated two major initiatives under the US Global Change Program: ARM (Atmospheric Radiation Measurements), and CHAMMP (Computer Hardware Advanced Mathematics and Model Physics). ARM is designed to use ground and air-craft based observations to document profiles of atmospheric composition, clouds, and radiative fluxes. With research and models of important physical processes, ARM will delineate the relationships between trace gases, aerosol and cloud structure, and radiative transfer in the atmosphere, and will improve the parameterization of global circulation models. The present GCMs do not model important feedbacks, including those from clouds, oceans, and land processes. The purpose of this workshop is to identify such potential feedbacks, to evaluate the uncertainties in the feedback processes (and, if possible, to parameterize the feedback processes so that they can be treated in a GCM), and to recommend research programs that will reduce the uncertainties in important feedback processes. Individual reports are processed separately for the data bases.

  9. Macroeconomics after the Crisis: Time to Deal with the Pretense-of-Knowledge Syndrome

    E-Print Network [OSTI]

    Caballero, Ricardo

    2010-09-27

    In this paper I argue that the current core of macroeconomics—by which I mainly mean the so-called dynamic stochastic general equilibrium approach—has become so mesmerized with its own internal logic that it has began to ...

  10. AGN feedback using AMR cosmological simulations

    E-Print Network [OSTI]

    Dubois, Yohan; Slyz, Adrianne; Teyssier, Romain

    2011-01-01

    Feedback processes are thought to solve some of the long-standing issues of the numerical modelling of galaxy formation: over-cooling, low angular momentum, massive blue galaxies, extra-galactic enrichment, etc. The accretion of gas onto super-massive black holes in the centre of massive galaxies can release tremendous amounts of energy to the surrounding medium. We show, with cosmological Adaptive Mesh Refinement simulations, how the growth of black holes is regulated by the feedback from Active Galactic Nuclei using a new dual jet/heating mechanism. We discuss how this large amount of feedback is able to modify the cold baryon content of galaxies, and perturb the properties of the hot plasma in their vicinity.

  11. Educational hardware for feedback systems

    E-Print Network [OSTI]

    Dancy, Isaac

    2004-01-01

    This thesis explores a variety of educational feedback systems with an emphasis on developing them for in-class demonstrations and in-depth student projects. The nature of feedback systems means there is never a shortage ...

  12. Attribution Analysis of Cloud Feedback 

    E-Print Network [OSTI]

    Zhou, Chen

    2014-07-15

    Uncertainty on cloud feedback is the primary contributor to the large spread of equilibrium climate sensitivity (ECS) in climate models. In this study, we compare the short-term cloud feedback in climate models with observations, and evaluate...

  13. UWB communication receiver feedback loop

    DOE Patents [OSTI]

    Spiridon, Alex (Palo Alto, CA); Benzel, Dave (Livermore, CA); Dowla, Farid U. (Castro Valley, CA); Nekoogar, Faranak (San Ramon, CA); Rosenbury, Erwin T. (Castro Valley, CA)

    2007-12-04

    A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.

  14. Current vs. Voltage Feedback Amplifiers

    E-Print Network [OSTI]

    Papavassiliou, Christos

    ?' In most applications, the differences between current feedback (CFB) and voltage feedback (VFB) are not apparent. Today's CFB and VFB amplifiers have comparable performance, but there are cer- tain unique Performance · Feedback Freedom Aside from the well-known attribute of CFB amplifiers, gain

  15. The macroeconomic effects of oil price shocks : why are the 2000s so different from the 1920s?

    E-Print Network [OSTI]

    Blanchard, Olivier

    2007-01-01

    We characterize the macroeconomic performance of a set of industrialized economies in the aftermath of the oil price shocks of the 1970s and of the last decade, focusing on the differences across episodes. We examine four ...

  16. Next Generation Environmentally Friendly Driving Feedback Systems...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Environmentally Friendly Driving Feedback Systems Research and Development Next Generation Environmentally Friendly Driving Feedback Systems Research and Development 2012 DOE...

  17. Regenerative feedback resonant circuit

    SciTech Connect (OSTI)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  18. Feedback | DOE PAGES

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal GasAdministration Medal01TechnicalScientific andScientificDOE DataPublic Access Feedback

  19. Information and Feedback Institutional Change Principle | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    successful applications of the information and feedback behavior change principle. Data, Feedback, and Awareness Lead to Big Energy Savings: The Navy used monthly energy...

  20. Feedback control of spin systems

    E-Print Network [OSTI]

    Claudio Altafini

    2006-01-03

    The feedback stabilization problem for ensembles of coupled spin 1/2 systems is discussed from a control theoretic perspective. The noninvasive nature of the bulk measurement allows for a fully unitary and deterministic closed loop. The Lyapunov-based feedback design presented does not require spins that are selectively addressable. With this method, it is possible to obtain control inputs also for difficult tasks, like suppressing undesired couplings in identical spin systems.

  1. Fundamental Characteristics of Feedback Technical Report of the ISIS Group

    E-Print Network [OSTI]

    Antsaklis, Panos

    Fundamental Characteristics of Feedback Mechanisms Technical Report of the ISIS Group at the University of Notre Dame ISIS-2011-005 (This report is a revised version of the ISIS-2009-006 report) Panos J everywhere? Deeper understanding would make it possible to un- This report (ISIS-2011-005, September 2011

  2. University of Edinburgh Feedback Standards & Guiding Principles

    E-Print Network [OSTI]

    Edinburgh, University of

    1 University of Edinburgh Feedback Standards & Guiding Principles Feedback plays a vital role out the standards required of feedback at Edinburgh, together with a framework of guiding principles within timetabled classes (tutorials, practicals, lectures) as well as more informally. And feedback

  3. Approved Module Information for BS3365, 2014/5 Module Title/Name: Macroeconomics Policy Module Code: BS3365

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    on macroeconomic policies 3 Oil and the macroeconomy ? Causes of oil price changes ? Oil prices; investment and depreciation ? Steady state ? Numerical examples 5 Economic Growth 2 ? Savings and investment Direct Investment and Policy (Professor Nigel Driffield) ? Benefits of FDI ? Aspects to FDI Policy

  4. The modelling of feedback in star formation simulations

    E-Print Network [OSTI]

    Dale, James E

    2015-01-01

    I review the current state of numerical simulations of stellar feedback in the context of star formation at scales ranging from the formation of individual stars to models of galaxy formation including cosmic reionisation. I survey the wealth of algorithms developed recently to solve the radiative transfer problem and to simulate stellar winds, supernovae and protostellar jets. I discuss the results of these simulations with regard to star formation in molecular clouds, the interaction of different feedback mechanisms with each other and with magnetic fields, and in the wider context of galactic-- and cosmological--scale simulations.

  5. Model documentation report: Macroeconomic Activity Module (MAM) of the National Energy Modeling System

    SciTech Connect (OSTI)

    NONE

    1997-02-01

    This report documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Macroeconomic Activity Module (MAM) used to develop the Annual Energy Outlook for 1997 (AEO 97). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code. This document serves three purposes. First it is a reference document providing a detailed description of the NEMS MAM used for the AEO 1997 production runs for model analysts, users, and the public. Second, this report meets the legal requirement of the Energy Information Administration (EIA) to provide adequate documentation in support of its models. Third, it facilitates continuity in model development by providing documentation from which energy analysts can undertake model enhancements, data updates, and parameter refinements as future projects.

  6. Protoplanetary disks including radiative feedback from accreting planets

    E-Print Network [OSTI]

    Montesinos, Matias; Perez, Sebastian; Baruteau, Clement; Casassus, Simon

    2015-01-01

    While recent observational progress is converging on the detection of compact regions of thermal emission due to embedded protoplanets, further theoretical predictions are needed to understand the response of a protoplanetary disk to the planet formation radiative feedback. This is particularly important to make predictions for the observability of circumplanetary regions. In this work we use 2D hydrodynamical simulations to examine the evolution of a viscous protoplanetary disk in which a luminous Jupiter-mass planet is embedded. We use an energy equation which includes the radiative heating of the planet as an additional mechanism for planet formation feedback. Several models are computed for planet luminosities ranging from $10^{-5}$ to $10^{-3}$ Solar luminosities. We find that the planet radiative feedback enhances the disk's accretion rate at the planet's orbital radius, producing a hotter and more luminous environement around the planet, independently of the prescription used to model the disk's turbul...

  7. Klystron equalization for RF feedback

    SciTech Connect (OSTI)

    Corredoura, P.

    1993-01-01

    The next generation of colliding beam storage rings support higher luminosities by significantly increasing the number of bunches and decreasing the spacing between respective bunches. The heavy beam loading requires large RF cavity detuning which drives several lower coupled bunch modes very strongly. One technique which has proven to be very successful in reducing the coupled bunch mode driving impedance is RF feedback around the klystron-cavity combination. The gain and bandwidth of the feedback loop is limited by the group delay around the feedback loop. Existing klystrons on the world market have not been optimized for this application and contribute a large portion of the total loop group delay. This paper describes a technique to reduce klystron group delay by adding an equalizing filter to the klystron RF drive. Such a filter was built and tested on a 500 kill klystron as part of the on going PEP-II R&D effort here at SLAC.

  8. Klystron equalization for RF feedback

    SciTech Connect (OSTI)

    Corredoura, P.

    1993-01-01

    The next generation of colliding beam storage rings support higher luminosities by significantly increasing the number of bunches and decreasing the spacing between respective bunches. The heavy beam loading requires large RF cavity detuning which drives several lower coupled bunch modes very strongly. One technique which has proven to be very successful in reducing the coupled bunch mode driving impedance is RF feedback around the klystron-cavity combination. The gain and bandwidth of the feedback loop is limited by the group delay around the feedback loop. Existing klystrons on the world market have not been optimized for this application and contribute a large portion of the total loop group delay. This paper describes a technique to reduce klystron group delay by adding an equalizing filter to the klystron RF drive. Such a filter was built and tested on a 500 kill klystron as part of the on going PEP-II R D effort here at SLAC.

  9. Delayed feedback control of fractional-order chaotic systems

    E-Print Network [OSTI]

    Aleksandar Gjurchinovski; Trifce Sandev; Viktor Urumov

    2011-07-06

    We study the possibility to stabilize unstable steady states and unstable periodic orbits in chaotic fractional-order dynamical systems by the time-delayed feedback method. By performing a linear stability analysis, we establish the parameter ranges for successful stabilization of unstable equilibria in the plane parametrizad by the feedback gain and the time delay. An insight into the control mechanism is gained by analyzing the characteristic equation of the controlled system, showing that the control scheme fails to control unstable equilibria having an odd number of positive real eigenvalues. We demonstrate that the method can also stabilize unstable periodic orbits for a suitable choice of the feedback gain, providing that the time delay is chosen to coincide with the period of the target orbit. In addition, it is shown numerically that delayed feedback control with a sinusoidally modulated time delay significantly enlarges the stability region of the steady states in comparison to the classical time-delayed feedback scheme with a constant delay.

  10. The Greenhouse Effect without Feedbacks

    E-Print Network [OSTI]

    The Greenhouse Effect without Feedbacks #12;Three Pillars Behind Climate Change! #12;1. Global. Greenhouse Gases have been on the increase. #12;3. The Greenhouse effect is a powerful theory that explains absorbed=rate emitted 30% reflected to space! #12;Computing T! no-greenhouse planet,! e.g., 78% N2, 21% O2

  11. Teachers' emotions and test feedback 

    E-Print Network [OSTI]

    Stough, Laura

    1998-01-01

    by considerable aå ect.Maria commented ` ` I don’ t deal real well with anger, OK ? That ’ s, that ’ s part of it ±I am very con ¯ ict averse [laughs] and I just don’ t like that con¯ ict ¼ ’ ’ (semester one,post-feedback interview). Incidents that teachers...

  12. LFSC - Linac Feedback Simulation Code

    SciTech Connect (OSTI)

    Ivanov, Valentin; /Fermilab

    2008-05-01

    The computer program LFSC (Feedback Simulation Code>) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output.

  13. MANEUVER REGULATION, TRANSVERSE FEEDBACK LINEARIZATION, AND ZERO

    E-Print Network [OSTI]

    Maggiore, Manfredi

    MANEUVER REGULATION, TRANSVERSE FEEDBACK LINEARIZATION, AND ZERO DYNAMICS Chris Nielsen,1 Manfredi focus is on output maneuver regulation where stabilizing transverse dynamics is a key requirement. Keywords: Maneuver regulation, path following, feedback linearization, zero dynamics, non-square systems

  14. Context-based visual feedback recognition

    E-Print Network [OSTI]

    Morency, Louis-Philippe, 1977-

    2007-01-01

    During face-to-face conversation, people use visual feedback (e.g., head and eye gesture) to communicate relevant information and to synchronize rhythm between participants. When recognizing visual feedback, people often ...

  15. Material feedback in digital design tools

    E-Print Network [OSTI]

    Stanton, Christian J

    2009-01-01

    How do design tools feedback material behavior to the designer? Digital design tools in use by designers today provide a rich environment for design of form but offer little feedback of the material that ultimately realize ...

  16. CRAD, Feedback and Continuous Improvement - DOE Headquarters...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    - DOE Headquarters - December 4, 2007 More Documents & Publications CRAD, Feedback and Continuous Improvement - DOE Headquarters - December 4, 2007 Differing Professional...

  17. Rf Feedback free electron laser

    DOE Patents [OSTI]

    Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

    1981-01-01

    A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  18. Develop feedback system for intelligent dynamic resource allocation to improve application performance.

    SciTech Connect (OSTI)

    Gentile, Ann C.; Brandt, James M.; Tucker, Thomas (Open Grid Computing, Inc., Austin, TX); Thompson, David

    2011-09-01

    This report provides documentation for the completion of the Sandia Level II milestone 'Develop feedback system for intelligent dynamic resource allocation to improve application performance'. This milestone demonstrates the use of a scalable data collection analysis and feedback system that enables insight into how an application is utilizing the hardware resources of a high performance computing (HPC) platform in a lightweight fashion. Further we demonstrate utilizing the same mechanisms used for transporting data for remote analysis and visualization to provide low latency run-time feedback to applications. The ultimate goal of this body of work is performance optimization in the face of the ever increasing size and complexity of HPC systems.

  19. On-line optical flow feedback for mobile robot localization/navigation 

    E-Print Network [OSTI]

    Sorensen, David Kristin

    2004-09-30

    ON-LINE OPTICAL FLOW FEEDBACK FOR MOBILE ROBOT LOCALIZATION/NAVIGATION A Thesis by DAVID KRISTIN SORENSEN 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 May 2003 Major Subject: Mechanical Engineering ON-LINE OPTICAL FLOW FEEDBACK FOR MOBILE ROBOT LOCALIZATION/NAVIGATION A Thesis by DAVID KRISTIN SORENSEN Submitted to Texas A&M University in partial fulfillment...

  20. Feedback enhanced plasma spray tool

    DOE Patents [OSTI]

    Gevelber, Michael Alan; Wroblewski, Donald Edward; Fincke, James Russell; Swank, William David; Haggard, Delon C.; Bewley, Randy Lee

    2005-11-22

    An improved automatic feedback control scheme enhances plasma spraying of powdered material through reduction of process variability and providing better ability to engineer coating structure. The present inventors discovered that controlling centroid position of the spatial distribution along with other output parameters, such as particle temperature, particle velocity, and molten mass flux rate, vastly increases control over the sprayed coating structure, including vertical and horizontal cracks, voids, and porosity. It also allows improved control over graded layers or compositionally varying layers of material, reduces variations, including variation in coating thickness, and allows increasing deposition rate. Various measurement and system control schemes are provided.

  1. Integrating User Feedback Log into Relevance Feedback by Coupled SVM for Content-Based Image Retrieval

    E-Print Network [OSTI]

    Lyu, Michael R.

    , the user feedback log is one of the most important resources to bridge the seman- tic gap problem in image to re- peat many rounds of feedback in order to achieve satisfac- tory results. Hence, the learning task

  2. Combining Feedback Absorption Spectroscopy, Amplified Resonance...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling Cummins...

  3. RF power recovery feedback circulator

    DOE Patents [OSTI]

    Sharamentov, Sergey I. (Bolingbrook, IL)

    2011-03-29

    A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.

  4. Optical feedback structures and methods of making

    DOE Patents [OSTI]

    Snee, Preston T; Chan, Yin Thai; Nocera, Daniel G; Bawendi, Moungi G

    2014-11-18

    An optical resonator can include an optical feedback structure disposed on a substrate, and a composite including a matrix including a chromophore. The composite disposed on the substrate and in optical communication with the optical feedback structure. The chromophore can be a semiconductor nanocrystal. The resonator can provide laser emission when excited.

  5. Nonlinearity of Carbon Cycle Feedbacks KIRSTEN ZICKFELD

    E-Print Network [OSTI]

    Schmittner, Andreas

    properties and anthropogenic CO2. These findings suggest that metrics of carbon cycle feedback that pos, human activities have emitted large amounts of carbon dioxide (CO2) into the atmosphere (490 PgC fromNonlinearity of Carbon Cycle Feedbacks KIRSTEN ZICKFELD Canadian Centre for Climate Modelling

  6. Thermodynamics of quantum feedback cooling

    E-Print Network [OSTI]

    Liuzzo-Scorpo, Pietro; Schmidt, Rebecca; Adesso, Gerardo

    2015-01-01

    The ability to initialize quantum registers in pure states lies at the core of many applications of quantum technologies, from sensing to quantum information processing and computation. In this paper we tackle the problem of increasing the polarization bias of an ensemble of two-level register spins by means of joint coherent manipulations, involving a second ensemble of ancillary spins, and energy dissipation into an external heat bath. We formulate this spin refrigeration protocol, akin to algorithmic cooling, in the general language of quantum feedback control, and identify the relevant thermodynamic variables involved. Our analysis is twofold: On the one hand, we assess the optimality of the protocol by means of suitable figures of merit, accounting for both its work cost and effectiveness. On the other hand, we characterise the nature of correlations built up between the register and the ancilla. In particular, we observe that neither the amount of classical correlations nor the quantum entanglement seem...

  7. Digital feedback in superconducting quantum circuits

    E-Print Network [OSTI]

    D. Ristè; L. DiCarlo

    2015-08-06

    This chapter covers the development of feedback control of superconducting qubits using projective measurement and a discrete set of conditional actions, here referred to as digital feedback. We begin with an overview of the applications of digital feedback in quantum computing. We then introduce an implementation of high-fidelity projective measurement of superconducting qubits. This development lays the ground for closed-loop control based on the binary measurement result. A first application of digital feedback control is fast and deterministic qubit reset, allowing the repeated initialization of a qubit more than an order of magnitude faster than its relaxation rate. A second application employs feedback in a multi-qubit setting to convert the generation of entanglement by parity measurement from probabilistic to deterministic, targeting an entangled state with the desired parity every time.

  8. Getting Useful Real-Time Feedback About Your Program | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Getting Useful Real-Time Feedback About Your Program Getting Useful Real-Time Feedback About Your Program Getting Useful Real-Time Feedback About Your Program, presentation slides...

  9. Post-Review Feedback Questionnaire for Evaluating the Peer Review...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Post-Review Feedback Questionnaire for Evaluating the Peer Review Process Post-Review Feedback Questionnaire for Evaluating the Peer Review Process EERE is committed to continuous...

  10. Desert dust suppressing precipitation: A possible desertification feedback loop

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Desert dust suppressing precipitation: A possible desertification feedback loop Daniel Rosenfeld of land use exposing the topsoil can initiate such a desertification feedback process. Satellite

  11. Contractor Rating and Feedback Systems | Department of Energy

    Energy Savers [EERE]

    Rating and Feedback Systems Contractor Rating and Feedback Systems Better Buildings Residential Workforce Business Partners Peer Exchange Call Series: Contractor Rating and...

  12. A Mechanism for Evaluating Feedback of E-Commerce Sites.

    E-Print Network [OSTI]

    Renaud, K.V.

    Renaud,K.V. Kotze,P. Van Dyk,T.J. The first IFIP conference on E-Commerce, E-Business, E-Government. I3E. Zurich, Switzerland, 4-5 October, 2001. IFIP

  13. Analyzing Fuel Saving Opportunities through Driver Feedback Mechanisms |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    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: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based Fuels Research at 1 Table ofDepartment of Energy Fuel Saving

  14. Version pressure feedback mechanisms for speculative versioning caches

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaonfor Direct Measurement(Journal Article)(Patent) | SciTech

  15. Version pressure feedback mechanisms for speculative versioning caches

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaonfor Direct Measurement(Journal Article)(Patent) | SciTech(Patent)

  16. Mechanical constraints as common ground between people and computers

    E-Print Network [OSTI]

    Patten, James McMichael, 1977-

    2006-01-01

    This thesis presents a new type of human-computer interface based on mechanical constraints that combines some of the tactile feedback and affordances of mechanical systems with the abstract computational power of modern ...

  17. Feedback Requirements for SASE-FELs

    SciTech Connect (OSTI)

    Loos, Henrik; /SLAC

    2012-07-06

    The operation of a Self Amplified Spontaneous Emission (SASE) Free Electron Lasers (FEL) at soft and hard X-ray wavelengths driven by a high brightness electron beam imposes strong requirements on the stability of the accelerator and feedback systems are necessary to both guarantee saturation of the SASE process as well as a stable photon beam for user experiments. Diagnostics for the relevant transverse and longitudinal beam parameters are presented and various examples of feedback systems for bunches with low repetition rate as well as systems for intra bunch train feedbacks are discussed.

  18. Dynamic control of rotating stall in axial flow compressors using aeromechanical feedback

    SciTech Connect (OSTI)

    Gysling, D.L.; Greitzer, E.M.

    1995-07-01

    Dynamic control of rotating stall in an axial flow compressor has been implemented using aeromechanical feedback. The control strategy developed used an array of wall jets, upstream of a single-stage compressor, which were regulated by locally reacting reed valves. These reed valves responded to the small-amplitude flow-field pressure perturbations that precede rotating stall. The valve design was such that the combined system, compressor plus reed valve controller, was stable under operating conditions that had been unstable without feedback. A 10 percent decrease in the stalling flow coefficient was obtained using the control strategy, and the extension of stall flow range was achieved with no measurable change in the steady-state performance of the compression system. The experiments demonstrate the first use of aeromechanical feedback to extend the stable operating range of an axial flow compressor, and the first use of local feedback and dynamic compensation techniques to suppress rotating stall. The design of the experiment was based on a two-dimensional stall inception model, which incorporated the effect of the aeromechanical feedback. The physical mechanism for rotating stall in axial flow compressors was examined with focus on the role of dynamic feedback in stabilizing compression system instability. As predicted and experimentally demonstrated, the effectiveness of the aeromechanical control strategy depends on a set of nondimensional control parameters that determine the interaction of the control strategy and the rotating stall dynamics.

  19. Context-based Visual Feedback Recognition

    E-Print Network [OSTI]

    Morency, Louis-Philippe

    2006-11-15

    During face-to-face conversation, people use visual feedback (e.g.,head and eye gesture) to communicate relevant information and tosynchronize rhythm between participants. When recognizing visualfeedback, people often rely ...

  20. Decomposition of radiational effects of model feedbacks

    SciTech Connect (OSTI)

    Ellsaesser, H.W.; MacCracken, M.C.; Potter, G.L.; Mitchell, C.S.

    1981-08-01

    Three separate doubled CO/sub 2/ experiments with the statistical dynamic model are used to illustrate efforts to study the climate dynamics, feedbacks, and interrelationships of meteorological parameters by decomposing and isolating their individual effects on radiation transport.

  1. Feedback controller parameterizations for reinforcement learning

    E-Print Network [OSTI]

    Roberts, John William

    Reinforcement Learning offers a very general framework for learning controllers, but its effectiveness is closely tied to the controller parameterization used. Especially when learning feedback controllers for weakly stable ...

  2. Cirrus feedback on interannual climate fluctuations

    SciTech Connect (OSTI)

    Zhou, C.; Dessler, A. E.; Zelinka, M. D.; Yang, P.; Wang, T.

    2014-12-28

    Cirrus clouds are not only important in determining the current climate, but also play an important role in climate change and variability. Analysis of satellite observations shows that the amount and altitude of cirrus clouds (optical depth <3.6, cloud top pressure <440 hPa) increase in response to inter-annual surface warming. Thus, cirrus clouds are likely to act as a positive feedback on short-term climate fluctuations, by reducing the planet’s ability to radiate longwave radiation to space in response to planetary surface warming. Using cirrus cloud radiative kernels, the magnitude of cirrus feedback is estimated to be 0.20±0.21W/m2/°C, which is comparable to the surface albedo feedback. Most of the cirrus feedback comes from increasing cloud amount in the tropical tropopause layer (TTL) and subtropical upper troposphere.

  3. Global surface cooling: the atmospheric fast feedback response to a collapse of the thermohaline circulation

    E-Print Network [OSTI]

    Drijfhout, Sybren

    Global surface cooling: the atmospheric fast feedback response to a collapse of the thermohaline thermohaline circulation results in a global surface cooling of 0.72 K. The mechanisms that are responsible for this cooling are investigated. Additional experiments were performed with a one-dimensional radiative

  4. Pulse Sensitivity of the Luteinizing Hormone Promoter Is Determined by a Negative Feedback

    E-Print Network [OSTI]

    Lawson, Mark A.

    Pulse Sensitivity of the Luteinizing Hormone Promoter Is Determined by a Negative Feedback LoopRH. Alterations in pulse frequency and amplitude alter the relative levels of gonado- tropin synthesis and release. The mechanism of interpretation of GnRH pulse frequency and ampli- tude by gonadotropes is not understood. We

  5. Towards Understanding Architectural Tradeoffs in MEMS Closed-Loop Feedback Control

    E-Print Network [OSTI]

    Sherwood, Tim

    Towards Understanding Architectural Tradeoffs in MEMS Closed-Loop Feedback Control Greg Hoover, California 93106 sherwood@cs.ucsb.edu ABSTRACT Micro-Electro-Mechanical Systems (MEMS) combine litho on the scale of microns. However, the physical scale of MEMS devices can make controlling them computationally

  6. Does Formalized Scoring and Feedback Improve Resident Documentation Skills?

    E-Print Network [OSTI]

    Nauss, M D; Jaskulka, B

    2014-01-01

    111 Does Formalized Scoring and Feedback Improve Residentand any associated symptoms? Does the HPI contain pertinent

  7. Coherent control and feedback cooling in a remotely-coupled hybrid atom-optomechanical system

    E-Print Network [OSTI]

    James S. Bennett; Lars S. Madsen; Mark Baker; Halina Rubinsztein-Dunlop; Warwick P Bowen

    2014-06-30

    Cooling to the motional ground state is an important first step in the preparation of nonclassical states of mesoscopic mechanical oscillators. Light-mediated coupling to a remote atomic ensemble has been proposed as a method to reach the ground state for low frequency oscillators. The ground state can also be reached using optical measurement followed by feedback control. Here we investigate the possibility of enhanced cooling by combining these two approaches. The combination, in general, outperforms either individual technique, though atomic ensemble-based cooling and feedback cooling each individually dominate over large regions of parameter space.

  8. Is transverse feedback necessary for the SSC emittance preservation? (Vibration noise analysis and feedback parameters optimization)

    SciTech Connect (OSTI)

    Parkhomchuk, V.V.; Shiltsev, V.D.

    1993-06-01

    The paper considers the Superconducting Super Collider (SSC) site ground motion measurements as well as data from accelerators worldwide about noises that worsen beam performance. Unacceptably fast emittance growth due to these noises is predicted for the SSC. A transverse feedback system was found to be the only satisfactory alternative to prevent emittance decay. Optimization of the primary feedback parameters was done.

  9. Effect of a detailed radial core expansion reactivity feedback model on ATWS calculations using SASSYS/SAS4A

    SciTech Connect (OSTI)

    Wigeland, R.A.

    1986-01-01

    The present emphasis on inherent safety and inherently safe designs for liquid-metal reactors has resulted in a need to represent the various reactivity feedback mechanisms as accurately as possible. In particular, the reactivity feedback from radial core expansion has been found to provide the dominant negative feedback contribution in postulated anticipated transient without scram (ATWS) events. Review of the existing modeling in the SASSYS/SAS4A computer code system revealed that while the modeling may be adequate for the early phases of various unprotected transients, the accuracy would be less than desirable for the extended transients which typically occur for inherently safe designs. The existing model for calculating the reactivity feedback from radial core expansion uses a feedback from radial core expansion uses a feedback coefficient in conjunction with changes in the temperatures of the grid support plate and the above-core load pad. The accuracy of this approach is determined partly by the conditions used in deriving the feedback coefficient, and their relevance to the transient being investigated. Accuracy is also affected by the need to include effects other than those that could be directly related to changes in the grid plate and above-core load pad temperatures, such as subassembly bowing and the potential for clearances to occur between subassemblies in the above-core load pad region. As a result, a detailed model was developed in an attempt to account for these and other effects in a more mechanistic form.

  10. PEP-II Transverse Feedback Electronics Upgrade

    SciTech Connect (OSTI)

    Weber, J.M.; Chin, M.J.; Doolittle, L.R.; Akre, R.; /SLAC

    2006-03-13

    The PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC) requires an upgrade of the transverse feedback system electronics. The new electronics require 12-bit resolution and a minimum sampling rate of 238 Msps. A Field Programmable Gate Array (FPGA) is used to implement the feedback algorithm. The FPGA also contains an embedded PowerPC 405 (PPC-405) processor to run control system interface software for data retrieval, diagnostics, and system monitoring. The design of this system is based on the Xilinx{reg_sign} ML300 Development Platform, a circuit board set containing an FPGA with an embedded processor, a large memory bank, and other peripherals. This paper discusses the design of a digital feedback system based on an FPGA with an embedded processor. Discussion will include specifications, component selection, and integration with the ML300 design.

  11. PEP-II Transverse Feedback Electronics Upgrade

    SciTech Connect (OSTI)

    Weber, J.; Chin, M.; Doolittle, L.; Akre, R.

    2005-05-09

    The PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC) requires an upgrade of the transverse feedback system electronics. The new electronics require 12-bit resolution and a minimum sampling rate of 238 Msps. A Field Programmable Gate Array (FPGA) is used to implement the feedback algorithm. The FPGA also contains an embedded PowerPC 405 (PPC-405) processor to run control system interface software for data retrieval, diagnostics, and system monitoring. The design of this system is based on the Xilinx(R) ML300 Development Platform, a circuit board set containing an FPGA with an embedded processor, a large memory bank, and other peripherals. This paper discusses the design of a digital feedback system based on an FPGA with an embedded processor. Discussion will include specifications, component selection, and integration with the ML300 design.

  12. Implementing Feedback in Simulations of Galaxy Formation: A Survey of Methods

    E-Print Network [OSTI]

    R. J. Thacker; H. M. P. Couchman

    2000-01-15

    We present a detailed investigation of different approaches to modeling feedback in simulations of galaxy formation. Gas-dynamic forces are evaluated using Smoothed Particle Hydrodynamics (SPH) while star formation and supernova feedback are included using a three parameter model which determines the star formation rate normalization, feedback energy and lifetime of feedback regions. The star formation rate is calculated using a Lagrangian Schmidt Law for all gas particles which satisfy temperature, density and convergent flow criteria. Feedback is incorporated as thermal heating of the ISM. We compare the effects of distributing this energy over the smoothing scale or depositing it on a single particle. Radiative losses are prevented from heated particles by adjusting the density used in radiative cooling. We test the models on the formation of galaxies from cosmological initial conditions and also on isolated Milky Way and dwarf galaxies. Extremely violent feedback is necessary to produce a gas disk with angular momentum remotely close to that of observed disk galaxies. This is a result of the extreme central concentration of the dark halos in the sCDM model, and the pervasiveness of the core-halo angular momentum transport mechanism. We emphasize that the disks formed in hierarchical simulations are partially a numerical artifact produced by the minimum mass scale of the simulation acting as a highly efficient `support' mechanism. Disk formation is strongly affected by the treatment of dense regions in SPH, which along with the difficulty of representing the hierarchical formation process, means that realistic simulations of galaxy formation require far higher resolution than currently used.

  13. The Impact of Performance Feedback on School Psychologists' Roles and SLD Assessments

    E-Print Network [OSTI]

    Stomel, Danielle Eryn

    2015-01-01

    for all three schools during the performance feedback phase.consultation and performance feedback. School PsychologyThe Impact of Performance Feedback on School Psychologists’

  14. Stellar feedback efficiencies: supernovae versus stellar winds

    E-Print Network [OSTI]

    Fierlinger, Katharina M; Ntormousi, Evangelia; Fierlinger, Peter; Schartmann, Marc; Ballone, Alessandro; Krause, Martin G H; Diehl, Roland

    2015-01-01

    Stellar winds and supernova (SN) explosions of massive stars ("stellar feedback") create bubbles in the interstellar medium (ISM) and insert newly produced heavy elements and kinetic energy into their surroundings, possibly driving turbulence. Most of this energy is thermalized and immediately removed from the ISM by radiative cooling. The rest is available for driving ISM dynamics. In this work we estimate the amount of feedback energy retained as kinetic energy when the bubble walls have decelerated to the sound speed of the ambient medium. We show that the feedback of the most massive star outweighs the feedback from less massive stars. For a giant molecular cloud (GMC) mass of 1e5 solar masses (as e.g. found in the Orion GMCs) and a star formation efficiency of 8% the initial mass function predicts a most massive star of approximately 60 solar masses. For this stellar evolution model we test the dependence of the retained kinetic energy of the cold GMC gas on the inclusion of stellar winds. In our model w...

  15. Predictive Limited Feedback for Cooperative Transmission

    E-Print Network [OSTI]

    Heath Jr., - Robert W.

    to improve sum-rates and reduce outages. Users estimate and feedback CSI of the desired and multiple information (CSI) at the cooperating base stations can be utilized to to improve data rates and reduce outages. Wireless Networking and Communications Group Department of Electrical and Computer Engineering

  16. Lyapunov Functions and Feedback in Nonlinear Control

    E-Print Network [OSTI]

    Maume-Deschamps, Véronique

    Lyapunov Functions and Feedback in Nonlinear Control Francis Clarke Professeur `a l@igd.univ-lyon1.fr Summary. The method of Lyapunov functions plays a central role in the study to consider nonsmooth Lyapunov functions, even if the underlying control dynamics are themselves smooth. We

  17. Electrothermal feedback in superconducting nanowire single-photon detectors

    E-Print Network [OSTI]

    Kerman, Andrew J.

    We investigate the role of electrothermal feedback in the operation of superconducting nanowire single-photon detectors (SNSPDs). It is found that the desired mode of operation for SNSPDs is only achieved if this feedback ...

  18. Feedback control of flow separation using synthetic jets 

    E-Print Network [OSTI]

    Kim, Kihwan

    2006-04-12

    The primary goal of this research is to assess the effect of synthetic jets on flow separation and provide a feedback control strategy for flow separation using synthetic jets. The feedback control synthesis is conducted based upon CFD simulation...

  19. Bunch-Motion Feedback for B-Factories

    E-Print Network [OSTI]

    Lambertson, G.R.

    2011-01-01

    and througb the driving klystron can be used but the degreethe feedback loop through the klystron and other circuits.feedback and by using the klystron-cavity system as a strong

  20. Visual-Feedback Distortion in a Robotic Rehabilitation

    E-Print Network [OSTI]

    Klatzky, Roberta

    INVITED P A P E R Visual-Feedback Distortion in a Robotic Rehabilitation Environment In a finger-motion rehabilitation trial, where a patient presses against robot resistance, progress can be aided by visual feedback Matsuoka ABSTRACT | We create a robotic rehabilitation environment that distorts the visual feedback

  1. Feedback Control Theory and Processing System Log Streams Research Project

    E-Print Network [OSTI]

    Tang, Pingzhong

    Feedback Control Theory and Processing System Log Streams by Wei Xu Research Project Submitted, and on exploring general techniques of applying feedback control theory to distributed computer systems. We have. All problems addressed are solved systematically with feedback-control-theory. We discuss three uses

  2. Consensus Building in Multi-vehicle Systems with Information Feedback

    E-Print Network [OSTI]

    Ren, Wei

    Consensus Building in Multi-vehicle Systems with Information Feedback Wei Ren Department@engineering.usu.edu Abstract-- In this paper, we study the problem of consensus building in multi-vehicle systems with information feedback. We will show how information feedback can be incorporated into the consensus building

  3. POLE PLACEMENT VIA OUTPUT FEEDBACK: A METHODOLOGY BASED ON

    E-Print Network [OSTI]

    Orsi, Robert

    POLE PLACEMENT VIA OUTPUT FEEDBACK: A METHODOLOGY BASED ON PROJECTIONS Kaiyang Yang and Robert Orsi feedback pole placement problems of the following rather general form: given n subsets of the complex plane, find a static output feedback that places in each of these subsets a pole of the closed loop system

  4. Power Management Mechanism Exploiting Network and Video Information over Wireless

    E-Print Network [OSTI]

    Bouras, Christos

    Power Management Mechanism Exploiting Network and Video Information over Wireless Links Christos- layer information from higher network layers may be utilized for more efficient power management that fine- tune transmission power according to information received from the transport (feedback reports

  5. Power Management Mechanism Exploiting Network and Video Information over Wireless

    E-Print Network [OSTI]

    Bouras, Christos

    Power Management Mechanism Exploiting Network and Video Information over Wireless Links Christos information from higher network layers may be utilized for more efficient power management in wireless- tune transmission power according to information received from the transport (feedback reports from

  6. Residential Feedback Devices and Programs. Opportunities for Natural Gas

    SciTech Connect (OSTI)

    Kerr, R.; Tondro, M.

    2012-12-01

    Behavior-based approaches have been a growing interest in the energy efficiency field over recent years and the use of residential energy feedback has garnered particular interest. By providing an increased level of detail, feedback can greatly increase a consumer’s understanding of how energy is used in their home. This project reviewed the existing body of research on electricity feedback to identify parallel lessons for gas, discussed the benefits and challenges of different types of feedback, and identifying three feedback options that show strong potential for natural gas savings.

  7. Residential Feedback Devices and Programs: Opportunities for Natural Gas

    SciTech Connect (OSTI)

    Kerr, R.; Tondro, M.

    2012-12-01

    Behavior-based approaches have been a growing interest in the energy efficiency field over recent years and the use of residential energy feedback has garnered particular interest. By providing an increased level of detail, feedback can greatly increase a consumer's understanding of how energy is used in their home. This project reviewed the existing body of research on electricity feedback to identify parallel lessons for gas, discussed the benefits and challenges of different types of feedback, and identifying three feedback options that show strong potential for natural gas savings.

  8. Information-technology approach to quantum feedback control

    E-Print Network [OSTI]

    Dao-Yi Dong; Chen-Bin Zhang; Zong-Hai Chen

    2005-03-01

    Quantum control theory is profitably reexamined from the perspective of quantum information, two results on the role of quantum information technology in quantum feedback control are presented and two quantum feedback control schemes, teleportation-based distant quantum feedback control and quantum feedback control with quantum cloning, are proposed. In the first feedback scheme, the output from the quantum system to be controlled is fed back into the distant actuator via teleportation to alter the dynamics of system. The result theoretically shows that it can accomplish some tasks such as distant feedback quantum control that Markovian or Bayesian quantum feedback can't complete. In the second feedback strategy, the design of quantum feedback control algorithms is separated into a state recognition step, which gives "on-off" signal to the actuator through recognizing some copies from the cloning machine, and a feedback (control) step using another copies of cloning machine. A compromise between information acquisition and measurement disturbance is established, and this strategy can perform some quantum control tasks with coherent feedback.

  9. Hybrid Geometric Feedback Control of Three-Dimensional Bipedal Robotic Walkers with Knees and Feet 

    E-Print Network [OSTI]

    Sinnet, Ryan Wesley

    2012-07-16

    &M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Aaron D. Ames Committee Members, Gholamreza Langari Richard J. Malak Robin R. Murphy Head of Department, Dennis O?Neal May 2011... Committee: Dr. Aaron D. Ames This thesis poses a feedback control method for obtaining humanlike bipedal walking on a human-inspired hybrid biped model. The end goal was to understand better the fundamental mechanisms that underlie bipedal walking...

  10. Frequency-feedback cavity enhanced spectrometer

    DOE Patents [OSTI]

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  11. Quantum feedback control and classical control theory

    E-Print Network [OSTI]

    Andrew C. Doherty; Salman Habib; Kurt Jacobs; Hideo Mabuchi; Sze M. Tan

    2000-03-09

    We introduce and discuss the problem of quantum feedback control in the context of established formulations of classical control theory, examining conceptual analogies and essential differences. We describe the application of state-observer based control laws, familiar in classical control theory, to quantum systems and apply our methods to the particular case of switching the state of a particle in a double-well potential.

  12. BLACK HOLE FORAGING: FEEDBACK DRIVES FEEDING

    SciTech Connect (OSTI)

    Dehnen, Walter; King, Andrew, E-mail: wd11@leicester.ac.uk, E-mail: ark@astro.le.ac.uk [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)] [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)

    2013-11-10

    We suggest a new picture of supermassive black hole (SMBH) growth in galaxy centers. Momentum-driven feedback from an accreting hole gives significant orbital energy, but little angular momentum to the surrounding gas. Once central accretion drops, the feedback weakens and swept-up gas falls back toward the SMBH on near-parabolic orbits. These intersect near the black hole with partially opposed specific angular momenta, causing further infall and ultimately the formation of a small-scale accretion disk. The feeding rates into the disk typically exceed Eddington by factors of a few, growing the hole on the Salpeter timescale and stimulating further feedback. Natural consequences of this picture include (1) the formation and maintenance of a roughly toroidal distribution of obscuring matter near the hole; (2) random orientations of successive accretion disk episodes; (3) the possibility of rapid SMBH growth; (4) tidal disruption of stars and close binaries formed from infalling gas, resulting in visible flares and ejection of hypervelocity stars; (5) super-solar abundances of the matter accreting on to the SMBH; and (6) a lower central dark-matter density, and hence annihilation signal, than adiabatic SMBH growth implies. We also suggest a simple subgrid recipe for implementing this process in numerical simulations.

  13. Thermal Balance in the Intracluster Medium: Is AGN Feedback Necessary?

    E-Print Network [OSTI]

    Charlie Conroy; Jeremiah P. Ostriker

    2008-03-10

    A variety of physical heating mechanisms are combined with radiative cooling to explore, via one dimensional hydrodynamic simulations, the expected thermal properties of the intracluster medium (ICM) in the context of the cooling flow problem. Energy injection from type Ia supernovae, thermal conduction, and dynamical friction (DF) from orbiting satellite galaxies are considered. The novel feature of this work is the exploration of a wide range of efficiencies of each heating process. While the latter two can provide a substantial amount of energy, neither mechanism operating alone can produce nor maintain an ICM in thermal balance over cosmological timescales, in stark contrast with observations. For simulated clusters with initially isothermal temperature profiles, both mechanisms acting in combination result in long-term thermal balance for a range of ICM temperatures and for central electron densities less than n_e~0.02 cm^-3; at greater densities catastrophic cooling invariably occurs. Furthermore, these heating mechanisms can neither produce nor maintain clusters with a declining temperature profile in the central regions, implying that the observed "cooling-core'' clusters, which have such declining temperature profiles, cannot be maintained with these mechanisms alone. Thus, while there appears to be an abundant supply of energy capable of heating the ICM in clusters, it is extremely difficult for the energy deposition to occur in such a way that the ICM remains in thermal balance over cosmological time-scales. These results strongly suggest that a more dynamic heating process such as feedback from a central black hole is required to generate the properties of observed intracluster media. (ABRIDGED)

  14. Debt dependency, debt relief, and macroeconomic policies: how does the structure of external and domestic debt affect the well being of a country?s citizenry? 

    E-Print Network [OSTI]

    Burns, Jackie Rene

    2005-02-17

    -1 DEBT DEPENDENCY, DEBT RELIEF, AND MACROECONOMIC POLICIES: HOW DOES THE STRUCTURE OF EXTERNAL AND DOMESTIC DEBT AFFECT THE WELL BEING OF A COUNTRY?S CITIZENRY? A Dissertation by JACKIE R. BURNS Submitted to the Office of Graduate Studies... THE STRUCTURE OF EXTERNAL AND DOMESTIC DEBT AFFECT THE WELL BEING OF A COUNTRY?S CITIZENRY? A Dissertation by JACKIE R. BURNS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree...

  15. A comparison of some relevance feedback techniques 

    E-Print Network [OSTI]

    Cashman, Leslie Edward

    1972-01-01

    the relevant documents. Needless to say, perfect indexing does not exist in document retr1eval systems. Yet to use relevance feedback a basic assumption has to be made. Specifically 1t must be assumed that documents relevant to a given query will res1de... results. Out ut de ictin the functionin of each strate . The vector mentioned above is printed for each iteration of each strategy. At a glance it shows how the ranks of the relevant documents vacillate from one iteration to the next. In addition...

  16. External optical feedback in semiconductor lasers 

    E-Print Network [OSTI]

    Mebrahtu, Philemon

    1990-01-01

    S is the photon population, and K and K are constants relating the number of emitted photons to the output power being monitored. G is the single pass power gain in the laser diode cavity without feedback with the following condition to be satisfied: G RR =1... is coupled with light without delay in fiber coupler 3. The two signals with uncorrelated phase are then mixed in a Ge PIN diode biased at 15V. The RF signal is then amplified using an Avantek RF amplifier rated at 20 dB and this serves as an input to a...

  17. Self-assessing target with automatic feedback

    DOE Patents [OSTI]

    Larkin, Stephen W.; Kramer, Robert L.

    2004-03-02

    A self assessing target with four quadrants and a method of use thereof. Each quadrant containing possible causes for why shots are going into that particular quadrant rather than the center mass of the target. Each possible cause is followed by a solution intended to help the marksman correct the problem causing the marksman to shoot in that particular area. In addition, the self assessing target contains possible causes for general shooting errors and solutions to the causes of the general shooting error. The automatic feedback with instant suggestions and corrections enables the shooter to improve their marksmanship.

  18. The effects of feedback on freeway operations 

    E-Print Network [OSTI]

    Baker, Robert Lewis

    1967-01-01

    Model IV represents the open feedback ? feed-forward model as shown in Figure 10 ' 0 QA ftt )Q 0 (1 - p ) Pg 0 P6 g o (1 - p, ) Figure 10, Model IV Assume f(t ) to be an Erlang distribution with mean tA -- aA/bA and f(t ) to be an Erlang... = ? ' = 150 a b a variance = ? ' = 57. 5 2 b a = 150 b u ? ''=575 b2 or b =~=40 57. 5 a = 150 b = 600. 0 P ' ' F, Average volume = 600 vehicles per hour Time period = 5 minutes 60 Nu. . ber of time periods per hour = ? = 12 5 600 Average number...

  19. The role of stellar feedback in the dynamics of H II regions

    SciTech Connect (OSTI)

    Lopez, Laura A.; Castro, Daniel [MIT-Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-664H, Cambridge, MA 02139 (United States); Krumholz, Mark R.; Prochaska, J. Xavier; Ramirez-Ruiz, Enrico [Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95060 (United States); Bolatto, Alberto D., E-mail: lopez@space.mit.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2014-11-10

    Stellar feedback is often cited as the biggest uncertainty in galaxy formation models today. This uncertainty stems from a dearth of observational constraints as well as the great dynamic range between the small scales (?1 pc) where the feedback originates and the large scales of galaxies (?1 kpc) that are shaped by this feedback. To bridge this divide, in this paper we aim to assess observationally the role of stellar feedback at the intermediate scales of H II regions (?10-100 pc). In particular, we employ multiwavelength data to examine several stellar feedback mechanisms in a sample of 32 H II regions (with ages ?3-10 Myr) in the Large and Small Magellanic Clouds, respectively. Using optical, infrared, radio, and X-ray images, we measure the pressures exerted on the shells from the direct stellar radiation, the dust-processed radiation, the warm ionized gas, and the hot X-ray-emitting gas. We find that the warm ionized gas dominates over the other terms in all of the sources, although two have comparable dust-processed radiation pressures to their warm gas pressures. The hot gas pressures are comparatively weak, while the direct radiation pressures are one to two orders of magnitude below the other terms. We discuss the implications of these results, particularly highlighting evidence for hot gas leakage from the H II shells and regarding the momentum deposition from the dust-processed radiation to the warm gas. Furthermore, we emphasize that similar observational work should be done on very young H II regions to test whether direct radiation pressure and hot gas can drive the dynamics at early times.

  20. Effect of downstream feedback on the achievable performance of feedback control loops for serial processes

    E-Print Network [OSTI]

    Duffy, Ken

    -- Optimal control, multivariate control, serial processes, process control. I. INTRODUCTION The term serial-- This paper deals with feedback control of serial processes, that is, processes formed by the series control and feedforward action. The problem is addressed using an H2 optimal performance criterion

  1. The super star cluster driven feedback in ESO338-IG04 and Haro 11

    E-Print Network [OSTI]

    Bik, Arjan; Menacho, Veronica; Adamo, Angela; Hayes, Matthew; Melinder, Jens; Amram, Philippe

    2015-01-01

    The stellar content of young massive star clusters emit large amounts of Lyman continuum photons and inject momentum into the inter stellar medium (ISM) by the strong stellar winds of the most massive stars in the cluster. When the most massive stars explode as supernovae, large amounts of mechanical energy are injected in the ISM. A detailed study of the ISM around these massive cluster provides insights on the effect of cluster feedback. We present high quality integral field spectroscopy taken with VLT/MUSE of two starburst galaxies: ESO 338-IG04 and Haro 11. Both galaxies contain a significant number of super star clusters. The MUSE data provide us with an unprecedented view of the state and kinematics of the ionized gas in the galaxy allowing us to study the effect of stellar feedback on small and large spatial scales. We present our recent results on studying the ISM state of these two galaxies. The data of both galaxies show that the mechanical and ionization feedback of the super star clusters in the ...

  2. Data, Feedback, & Awareness Lead to Big Energy Savings | Department...

    Broader source: Energy.gov (indexed) [DOE]

    Data, Feedback, & Awareness Lead to Big Energy Savings Fact sheet describes how the Navy Region Southwest Metro San Diego Area (NRSMSD) regional energy management team achieved...

  3. Feedbacks between hydrological heterogeneity and bioremediation induced biogeochemical transformations

    E-Print Network [OSTI]

    Englert, A.

    2009-01-01

    Water Resources Research 2008, 44, W10412, doi:10.1029/2007WR006425. Supporting Information Feedbacks Between Hydrological Heterogeneity and Bioremediation

  4. Reduced-Order Model Based Feedback Control For Modified Hasegawa...

    Office of Scientific and Technical Information (OSTI)

    design problems) is applied to obtain a low dimensional model of the linearized MHW equation. Then a modelbased feedback controller is designed for the reduced order model using...

  5. Fermilab | Fermilab at Work | Web Form | Feedback Form

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Feedback Form Use the form below to submit a suggestion to senior management. Required fields are marked with an asterisk (*). Suggestion: Name: Email Address: Submit Last modified...

  6. Code design for erasure channels with limited or noisy feedback 

    E-Print Network [OSTI]

    Nagasubramanian, Karthik

    2009-05-15

    The availability of feedback in communication channels can significantly increase the reliability of transmission while decreasing the encoding and decoding complexity. Most of the applications like cellular telephony, ...

  7. Feedback cooling of the normal modes of a massive electromechanical system to submillikelvin temperature

    E-Print Network [OSTI]

    A. Vinante; M. Bignotto; M. Bonaldi; M. Cerdonio; L. Conti; P. Falferi; N. Liguori; S. Longo; R. Mezzena; A. Ortolan; G. A. Prodi; F. Salemi; L. Taffarello; G. Vedovato; S. Vitale; J. -P. Zendri

    2008-09-18

    We apply a feedback cooling technique to simultaneously cool the three electromechanical normal modes of the ton-scale resonant-bar gravitational wave detector AURIGA. The measuring system is based on a dc Superconducting Quantum Interference Device (SQUID) amplifier, and the feedback cooling is applied electronically to the input circuit of the SQUID. Starting from a bath temperature of 4.2 K, we achieve a minimum temperature of 0.17 mK for the coolest normal mode. The same technique, implemented in a dedicated experiment at subkelvin bath temperature and with a quantum limited SQUID, could allow to approach the quantum ground state of a kilogram-scale mechanical resonator.

  8. Characterization of Robust Feedback Nash Equilibrium for Multi-Channel Systems

    E-Print Network [OSTI]

    Gupta, Vijay

    Characterization of Robust Feedback Nash Equilibrium for Multi-Channel Systems Getachew K. Befekadu the feedback Nash equilibria via a set of stabilizing state-feedback solutions corresponding to a family for the existence of a feedback Nash equilibrium, whereas the set of robust stabilizing state-feedback solutions

  9. Essays on Macroeconomics

    E-Print Network [OSTI]

    Ji, Ting

    2015-01-01

    rates and the Altham statistics for India in the previousMoreover, India shows very high Altham statistics inSection 2.1, India shows very high Altham statistics, while

  10. Essays on Macroeconomics

    E-Print Network [OSTI]

    Ji, Ting

    2015-01-01

    Pro- cess versus Product Innovation. Edward ElgarMeschede, M. (2001). Product Innovation, Process Innovation,of Process and Product Innovation. Journal of Economic

  11. Essays in Macroeconomic Analysis

    E-Print Network [OSTI]

    Valcarcel, Victor J.

    2008-07-31

    ON PRIVATE SPENDING: A NEW KEYNESIAN APPROACH. This chapter promotes a structural model based on first principles of an economy populated by two types of consumer, with different saving behaviors, and two types of firms which produce either durable... or non-durable goods in the presence of sticky prices. While the micro-foundations of this model, when fully specified, allow for price staggering and consumer myopia in the New Keynesian tradition, a Real Business Cycle (RBC) view is nested as well...

  12. Three essays on macroeconomics

    E-Print Network [OSTI]

    Pruitt, Seth James

    2008-01-01

    value; ( 2) the ?nal productivity measurement that the ?rmpreliminary measurement of log-productivity Z 0 it is theget a new measurement of time t log-productivity, Z 1 . I t+

  13. Essays on Macroeconomics

    E-Print Network [OSTI]

    Llosa, Luis Gonzalo

    2012-01-01

    A Microfounded Business Cycle Model . . . . . . . . . . .A Real Business Cycle Model . . . . . . . . . . . .A Real Business Cycle Model . . . . .

  14. Three essays in macroeconomics

    E-Print Network [OSTI]

    Auer, Raphael Anton Maximilian Peter Gabriel

    2006-01-01

    This thesis is a collection of three essays on international trade and economic growth. Chapter 1 analyzes the dynamic gains from trade in a Hecksher-Ohlin economy with endogenous factor accumulation. In a framework where ...

  15. Macroeconomic Activity Module

    Gasoline and Diesel Fuel Update (EIA)

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (Billion Cubic Feet)DecadeYear Jan Feb Mar Apr 2012 2013(MillionYear5,020CubicCubic(Million::

  16. Does Beamforming achieve Outage Capacity with Direction Feedback?

    E-Print Network [OSTI]

    Jafar, Syed A.

    Does Beamforming achieve Outage Capacity with Direction Feedback? Sudhir Srinivasa and Syed Ali: syed@ece.uci.edu, sudhirs@uci.edu Email: sriram@ece.utexas.edu Abstract We explore the outage capacity of outage capacity for a quantized channel direction feedback system. The technique is used to establish

  17. Handy feedback: Connecting smart meters with mobile phones

    E-Print Network [OSTI]

    and immediate feedback between 5% and 15% of the electrical household energy consumption can be saved [4 limitations of existing electricity consumption monitor- ing systems. It offers the possibility system provides both: real-time feedback on the entire electricity usage and on the consumption of many

  18. Perceptual Media Compression for Multiple Viewers with Feedback Delay

    E-Print Network [OSTI]

    Oleg, Komogortsev - Department of Computer Science, Texas State University

    into the impact that such a method can have on transmission bandwidth and computational burden reduction ­ computer conferencing, teleconferencing, and videoconferencing; J.5 [Computers in Other Systems]: Social Perceptual media adaptation, multi-viewer setup. 1. IMPACT OF THE FEEDBACK DELAY Feedback delay is the period

  19. Electrooptic light modulator with improved response linearity using optical feedback 

    E-Print Network [OSTI]

    Bhatranand, Apichai

    2005-11-01

    output, the magnitude of the optical feedback and the substrate temperature were adjusted. The feedback level was altered by applying refractive index-matching liquid to one or both ends of the waveguide at the edges of the crystal. It was found that a...

  20. Behavioral/Systems/Cognitive Visual Feedback Control of Hand Movements

    E-Print Network [OSTI]

    Knill, David C.

    Behavioral/Systems/Cognitive Visual Feedback Control of Hand Movements Jeffrey A. Saunders investigated what visual information contributes to on-line control of hand movements. It has been suggested.Weusedaperturbationmethod to determine the relative contributions of motion and position information to feedback control. Subjects

  1. Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback

    E-Print Network [OSTI]

    Modular Quantum Memories Using Passive Linear Optics and Coherent Feedback Hendra I. Nurdin photon pulsed optical field has a conceptually simple modular realization using only passive linear optics and coherent feedback. We exploit the idea that two decaying optical cavities can be coupled

  2. Combustion diagnostic for active engine feedback control

    DOE Patents [OSTI]

    Green, Jr., Johney Boyd (Knoxville, TN); Daw, Charles Stuart (Knoxville, TN); Wagner, Robert Milton (Knoxville, TN)

    2007-10-02

    This invention detects the crank angle location where combustion switches from premixed to diffusion, referred to as the transition index, and uses that location to define integration limits that measure the portions of heat released during the combustion process that occur during the premixed and diffusion phases. Those integrated premixed and diffusion values are used to develop a metric referred to as the combustion index. The combustion index is defined as the integrated diffusion contribution divided by the integrated premixed contribution. As the EGR rate is increased enough to enter the low temperature combustion regime, PM emissions decrease because more of the combustion process is occurring over the premixed portion of the heat release rate profile and the diffusion portion has been significantly reduced. This information is used to detect when the engine is or is not operating in a low temperature combustion mode and provides that feedback to an engine control algorithm.

  3. QAM Adaptive Measurements Feedback Quantum Receiver Performance

    E-Print Network [OSTI]

    Tian Chen; Ke Li; Yuan Zuo; Bing Zhu

    2015-04-11

    We theoretically study the quantum receivers with adaptive measurements feedback for discriminating quadrature amplitude modulation (QAM) coherent states in terms of average symbol error rate. For rectangular 16-QAM signal set, with different stages of adaptive measurements, the effects of realistic imperfection parameters including the sub-unity quantum efficiency and the dark counts of on-off detectors, as well as the transmittance of beam splitters and the mode mismatch factor between the signal and local oscillating fields on the symbol error rate are separately investigated through Monte Carlo simulations. Using photon-number-resolving detectors (PNRD) instead of on-off detectors, all the effects on the symbol error rate due to the above four imperfections can be suppressed in a certain degree. The finite resolution and PNR capability of PNRDs are also considered. We find that for currently available technology, the receiver shows a reasonable gain from the standard quantum limit (SQL) with moderate stages.

  4. Stellar feedback by radiation pressure and photoionization

    E-Print Network [OSTI]

    Sales, Laura V; Springel, Volker; Petkova, Margarita

    2013-01-01

    The relative impact of radiation pressure and photoionization feedback from young stars on surrounding gas is studied with hydrodynamic radiative transfer (RT) simulations. The calculations focus on the single-scattering (direct radiation pressure) and optically thick regime, and adopt a moment-based RT-method implemented in the moving-mesh code AREPO. The source luminosity, gas density profile and initial temperature are varied. At typical temperatures and densities of molecular clouds, radiation pressure drives velocities of order ~20 km/s over 1-5 Myr; enough to unbind the smaller clouds. However, these estimates ignore the effects of photoionization that naturally occur concurrently. When radiation pressure and photoionization act together, the latter is substantially more efficient, inducing velocities comparable to the sound speed of the hot ionized medium (10-15 km/s) on timescales far shorter than required for accumulating similar momentum with radiation pressure. This mismatch allows photoionization ...

  5. Fighting Decoherence by Feedback-controlled Dissipation

    E-Print Network [OSTI]

    Gernot Schaller

    2012-06-12

    Repeated closed-loop control operations acting as piecewise-constant Liouville superoperators conditioned on the outcomes of regularly performed measurements may effectively be described by a fixed-point iteration for the density matrix. Even when all Liouville superoperators point to the completely mixed state, feedback of the measurement result may lead to a pure state, which can be interpreted as selective dampening of undesired states. Using a microscopic model, we exemplify this for a single qubit, which can be purified in an arbitrary single-qubit state by tuning the measurement direction and two qubits that may be purified towards a Bell state by applying a special continuous two-local measurement. The method does not require precise knowledge of decoherence channels and works for large reservoir temperatures provided measurement, processing, and control can be implemented in a continuous fashion.

  6. Feedback stabilisation of switched systems via iterative approximate eigenvector assignment

    E-Print Network [OSTI]

    Haimovich, Hernan

    2010-01-01

    This paper presents and implements an iterative feedback design algorithm for stabilisation of discrete-time switched systems under arbitrary switching regimes. The algorithm seeks state feedback gains so that the closed-loop switching system admits a common quadratic Lyapunov function (CQLF) and hence is uniformly globally exponentially stable. Although the feedback design problem considered can be solved directly via linear matrix inequalities (LMIs), direct application of LMIs for feedback design does not provide information on closed-loop system structure. In contrast, the feedback matrices computed by the proposed algorithm assign closed-loop structure approximating that required to satisfy Lie-algebraic conditions that guarantee existence of a CQLF. The main contribution of the paper is to provide, for single-input systems, a numerical implementation of the algorithm based on iterative approximate common eigenvector assignment, and to establish cases where such algorithm is guaranteed to succeed. We inc...

  7. Pulsed klystrons with feedback controlled mod-anode modulators

    SciTech Connect (OSTI)

    Reass, William A [Los Alamos National Laboratory; Baca, David M [Los Alamos National Laboratory; Jerry, Davis L [Los Alamos National Laboratory; Rees, Daniel E [Los Alamos National Laboratory

    2009-01-01

    This paper describes a fast rise and fall, totem-pole mod-anode modulators for klystron application. Details of these systems as recently installed utilizing a beam switch tube ''on-deck'' and a planar triode ''off-deck'' in a grid-catch feedback regulated configuration will be provided. The grid-catch configuration regulates the klystron mod-anode voltage at a specified set-point during switching as well as providing a control mechanism that flat-top regulates the klystron beam current during the pulse. This flat-topped klystron beam current is maintained while the capacitor bank droops. In addition, we will review more modern on-deck designs using a high gain, high voltage planar triode as a regulating and switching element. These designs are being developed, tested, and implemented for the Los Alamos Neutron Science Center (LANSCE) accelerator refurbishment project, ''LANSCE-R''. An advantage of the planar triode is that the tube can be directly operated with solid state linear components and provides for a very compact design. The tubes are inexpensive compared to stacked semiconductor switching assemblies and also provide a linear control capability. Details of these designs are provided as well as operational and developmental results.

  8. Stabilising falling liquid film flows using feedback control

    E-Print Network [OSTI]

    Thompson, Alice B; Pavliotis, Grigorios A; Papageorgiou, Demetrios T

    2015-01-01

    The flow of a fluid layer with one interface exposed to the air and the other an inclined planar wall becomes unstable due to inertial effects when the fluid layer is sufficiently thick or the slope sufficiently steep. This free surface flow of a single fluid layer has industrial applications including coating and heat transfer, which benefit from smooth and wavy interfaces, respectively. Here we discuss how the dynamics of the system are altered by introducing deliberately spatially-varying or time-dependent perturbations via the injection and suction of fluid through the wall. We find that injection and suction is a remarkably effective control mechanism: the controls can be used to drive the system towards arbitrary steady states and travelling waves, and the qualitative effects are independent of the details of the flow modelling. Furthermore, the system can still be successfully controlled even if the feedback must be applied via a set of localised actuators, and only a small number of system observation...

  9. Stellar and Quasar Feedback in Concert: Effects on AGN Accretion, Obscuration, and Outflows

    E-Print Network [OSTI]

    Hopkins, Philip F; Faucher-Giguere, Claude-Andre; Quataert, Eliot; Murray, Norman

    2015-01-01

    We use hydrodynamic simulations to study the interaction of realistic active galactic nucleus (AGN) feedback mechanisms (accretion-disk winds & Compton heating) with a multi-phase interstellar medium (ISM). Our ISM model includes radiative cooling and explicit stellar feedback from multiple processes. We simulate radii ~0.1-100 pc around an isolated (non-merging) black hole. These are the scales where the accretion rate onto the black hole is determined and where AGN-powered winds and radiation couple to the ISM. Our primary results include: (1) The black hole accretion rate on these scales is determined by exchange of angular momentum between gas and stars in gravitational instabilities. This produces accretion rates of ~0.03-1 Msun/yr, sufficient to power a luminous AGN. (2) The gas disk in the galactic nucleus undergoes an initial burst of star formation followed by several Myrs where stellar feedback suppresses the star formation rate per dynamical time. (3) AGN winds injected at small radii with mome...

  10. Fervent: Chemistry-coupled, ionising and non-ionising radiative feedback in magnetohydrodynamical simulations

    E-Print Network [OSTI]

    Baczynski, C; Klessen, R S

    2015-01-01

    We introduce a radiative transfer code module for the magnetohydrodynamical adaptive mesh refinement code FLASH 4. It is coupled to an efficient chemical network which explicitly tracks the three hydrogen species H, H_2, H+ as well as C+ and CO. The module is geared towards modeling all relevant thermal feedback processes of massive stars, and is able to follow the non-equilibrium time-dependent thermal and chemical state of the present-day interstellar medium as well as that of dense molecular clouds. We describe in detail the implementation of all relevant thermal stellar feedback mechanisms, i.e. photoelectric, photoionization and H_2 dissociation heating as well as pumping of molecular hydrogen by UV photons. All included radiative feedback processes are extensively tested. We also compare our module to dedicated photon-dominated region (PDR) codes and find good agreement in our modeled hydrogen species once our radiative transfer solution reaches equilibrium. In addition, we show that the implemented rad...

  11. Escape fraction of ionizing photons during reionization: Effects due to supernova feedback and runaway ob stars

    SciTech Connect (OSTI)

    Kimm, Taysun; Cen, Renyue [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)

    2014-06-20

    The fraction of hydrogen ionizing photons escaping from galaxies into the intergalactic medium is a critical ingredient in the theory of reionization. We use two zoomed-in, high-resolution (4 pc), cosmological radiation hydrodynamic simulations with adaptive mesh refinement to investigate the impact of two physical mechanisms (supernova, SN, feedback, and runaway OB stars) on the escape fraction (f {sub esc}) at the epoch of reionization (z ? 7). We implement a new, physically motivated SN feedback model that can approximate the Sedov solutions at all (from the free expansion to snowplow) stages. We find that there is a significant time delay of about ten million years between the peak of star formation and that of escape fraction, due to the time required for the build-up and subsequent destruction of the star-forming cloud by SN feedback. Consequently, the photon number-weighted mean escape fraction for dwarf galaxies in halos of mass 10{sup 8}-10{sup 10.5} M {sub ?} is found to be ?f{sub esc}??11%, although instantaneous values of f {sub esc} > 20% are common when star formation is strongly modulated by the SN explosions. We find that the inclusion of runaway OB stars increases the mean escape fraction by 22% to ?f{sub esc}??14%. As SNe resulting from runaway OB stars tend to occur in less dense environments, the feedback effect is enhanced and star formation is further suppressed in halos with M{sub vir}?10{sup 9} M{sub ?} in the simulation with runaway OB stars compared with the model without them. While both our models produce enough ionizing photons to maintain a fully ionized universe at z ? 7 as observed, a still higher amount of ionizing photons at z ? 9 appears necessary to accommodate the high observed electron optical depth inferred from cosmic microwave background observations.

  12. Improved Prediction of the Temperature Feedback in TRISO-Fueled Reactors

    SciTech Connect (OSTI)

    Javier Ortensi; Abderrafi M. Ougouag

    2009-08-01

    The Doppler feedback mechanism is a major contributor to the passive safety of gas-cooled, graphite-moderated high temperature reactors that use fuel based on Tristructural-Isotropic coated particles. It follows that the correct prediction of the magnitude and time-dependence of this feedback effect is essential to the conduct of safety analyses for these reactors. We present a fuel conduction model for obtaining better estimates of the temperature feedback during moderate and fast transients. The fuel model has been incorporated in the CYNOD-THERMIX-KONVEK suite of coupled codes as a single TRISO particle within each calculation cell. The heat generation rate is scaled down from the neutronic solution and a Dirichlet boundary condition is imposed as the bulk graphite temperature from the thermal-hydraulic solution. This simplified approach yields similar results to those obtained with more complex methods, requiring multi-TRISO calculations within one control volume, but with much less computational effort. An analysis of the hypothetical total control ejection in the PBMR-400 design verifies the performance of the code during fast transients. In addition, the analysis of the earthquake-initiated event in the PBMR-400 design verifies the performance of the code during slow transients. These events clearly depict the improvement in the predictions of the fuel temperature, and consequently, of the power escalations. In addition, a brief study of the potential effects of particle layer de-bonding on the transient behavior of high temperature reactors is included. Although the formation of a gap occurs under special conditions its consequences on the dynamic behavior of the reactor should be analyzed. The presence of a gap in the fuel can cause some unusual reactor behavior during fast transients, but still the reactor shuts down due to the strong feedback effects.

  13. Feedback cooling of cantilever motion using a quantum point contact transducer

    SciTech Connect (OSTI)

    Montinaro, M.; Mehlin, A.; Solanki, H. S.; Peddibhotla, P.; Poggio, M.; Mack, S.; Awschalom, D. D.

    2012-09-24

    We use a quantum point contact (QPC) as a displacement transducer to measure and control the low-temperature thermal motion of a nearby micromechanical cantilever. The QPC is included in an active feedback loop designed to cool the cantilever's fundamental mechanical mode, achieving a squashing of the QPC noise at high gain. The minimum achieved effective mode temperature of 0.2 K and the displacement resolution of 10{sup -11} m/{radical}(Hz) are limited by the performance of the QPC as a one-dimensional conductor and by the cantilever-QPC capacitive coupling.

  14. Efficiency of feedback process in cavity quantum electrodynamics

    E-Print Network [OSTI]

    H. T. Fung; P. T. Leung

    2007-08-02

    Utilizing the continuous frequency mode quantization scheme, we study from first principle the efficiency of a feedback scheme that can generate maximally entangled states of two atoms in an optical cavity through their interactions with a single input photon. The spectral function of the photon emitted from the cavity, which will be used as the input of the next round in the feedback process, is obtained analytically. We find that the spectral function of the photon is modified in each round and deviates from the original one. The efficiency of the feedback scheme consequently deteriorates gradually after several rounds of operation.

  15. & Mechanical Engineering

    E-Print Network [OSTI]

    Zhou, Chongwu

    AME Aerospace & Mechanical Engineering #12;Aerospace and Mechanical Engineers design complex mechanical, thermal, uidic, acoustical, optical, and electronic systems, with characteristic sizes ranging and far underground, to near-Earth, planetary, interplanetary and galactic space. Aerospace and Mechanical

  16. CDM, Feedback and the Hubble Sequence

    E-Print Network [OSTI]

    Jesper Sommer-Larsen; Martin Gotz; Laura Portinari

    2002-06-26

    We have performed TreeSPH simulations of galaxy formation in a standard LCDM cosmology, including effects of star formation, energetic stellar feedback processes and a meta-galactic UV field, and obtain a mix of disk, lenticular and elliptical galaxies. The disk galaxies are deficient in angular momentum by only about a factor of two compared to observed disk galaxies. The stellar disks have approximately exponential surface density profiles, and those of the bulges range from exponential to r^{1/4}, as observed. The bulge-to-disk ratios of the disk galaxies are consistent with observations and likewise are their integrated B-V colours, which have been calculated using stellar population synthesis techniques. Furthermore, we can match the observed I-band Tully-Fisher (TF) relation, provided that the mass-to-light ratio of disk galaxies, (M/L_I), is about 0.8. The ellipticals and lenticulars have approximately r^{1/4} stellar surface density profiles, are dominated by non-disklike kinematics and flattened due to non-isotropic stellar velocity distributions, again consistent with observations.

  17. Low speed control of a DC motor driving a mechanical system with fuzzy adaptive compensation 

    E-Print Network [OSTI]

    Hyun, Dongyoon

    1997-01-01

    A fuzzy adaptive feedforward control scheme in conjunction with classical feedback control is proposed for the low speed control of DC motors driving mechanical systems in the presence of friction. In the fuzzy adaptive scheme, a fuzzy logic based...

  18. Feedback Controlled High Frequency Electrochemical Micromachining 

    E-Print Network [OSTI]

    Ozkeskin, Fatih Mert

    2008-10-10

    are different from those for silicon. A promising mass production method for micro/meso scale components is electrochemical micromachining. The complex system, however, requires high precision mechanical fixtures and sophisticated instrumentation for proper...

  19. Continuous execution : improving user feedback in the development cycle

    E-Print Network [OSTI]

    Su, Kevin

    2007-01-01

    Programming environments are increasing the amount of feedback given to users during the development cycle. This work continues with this trend by exploring continuous execution, a programming environment where the result ...

  20. Optimization of neural network feedback control systems using automatic differentiation

    E-Print Network [OSTI]

    Rollins, Elizabeth, S.M. Massachusetts Institute of Technology

    2009-01-01

    Optimal control problems can be challenging to solve, whether using analytic or numerical methods. This thesis examines the application of an adjoint method for optimal feedback control, which combines various algorithmic ...

  1. Pulsed Feedback Defers Cellular Differentiation Joe H. Levine1

    E-Print Network [OSTI]

    Elowitz, Michael

    cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving, Resuspension Media; Spo0AP , phosphorylated Spo0A * E-mail: melowitz@caltech.edu Introduction Cells are capable

  2. Comparative analysis of aviation safety information feedback systems

    E-Print Network [OSTI]

    Funahashi, Yoshifuru

    2010-01-01

    In the aviation system, there are several feedback systems to prevent an accident. First of all, the accident and serious incident reporting and investigation system is established by the Chicago Convention. In general, ...

  3. Power capping in SLURM First prototype results and feedback

    E-Print Network [OSTI]

    Lefèvre, Laurent

    Power capping in SLURM First prototype results and feedback Green days @Lille, November 2013;Green days @Lille, November 2013 | Matthieu Hautreux | 2/27 Power capping Green days @Lille, November 2013 | Matthieu Hautreux | 3/27 Power capping

  4. The impact of galactic feedback on the circumgalactic medium

    E-Print Network [OSTI]

    Suresh, Joshua

    Galactic feedback strongly affects the way galactic environments are enriched. We examine this connection by performing a suite of cosmological hydrodynamic simulations, exploring a range of parameters based on the galaxy ...

  5. Feedback Policies for Measurement-based Quantum State Manipulation

    E-Print Network [OSTI]

    Shuangshuang Fu; Guodong Shi; Alexandre Proutiere; Matthew R. James

    2014-10-24

    In this paper, we propose feedback designs for manipulating a quantum state to a target state by performing sequential measurements. In light of Belavkin's quantum feedback control theory, for a given set of (projective or non-projective) measurements and a given time horizon, we show that finding the measurement selection policy that maximizes the probability of successful state manipulation is an optimal control problem for a controlled Markovian process. The optimal policy is Markovian and can be solved by dynamical programming. Numerical examples indicate that making use of feedback information significantly improves the success probability compared to classical scheme without taking feedback. We also consider other objective functionals including maximizing the expected fidelity to the target state as well as minimizing the expected arrival time. The connections and differences among these objectives are also discussed.

  6. Improving Evolutionary Synthesis of MEMS through Fabrication and Testing Feedback

    E-Print Network [OSTI]

    Agogino, Alice M.

    Improving Evolutionary Synthesis of MEMS through Fabrication and Testing Feedback Raffi Kamalian a microelectromechanical system (MEMS) synthesis characterization study, four modifications to the objectives: MEMS, genetic algorithms, resonator design, evolutionary computer-aided design, validation. 1

  7. CRAD, NNSA- Feedback and Improvement Programs (F&I)

    Broader source: Energy.gov [DOE]

    CRAD for Feedback and Improvement Programs (F&I). Criteria Review and Approach Documents (CRADs) that can be used to conduct a well-organized and thorough assessment of elements of safety and health programs.

  8. Domestic Audiences, Policy Feedback, and Sequential Decisions During Military Interventions 

    E-Print Network [OSTI]

    Kuberski, Douglas Walter

    2011-02-22

    The literature on escalation situations and audience costs suggests that democratic executives tend to increase commitment to a foreign policy in response to negative feedback. However, real-world cases from international ...

  9. Adaptive method with intercessory feedback control for an intelligent agent

    DOE Patents [OSTI]

    Goldsmith, Steven Y.

    2004-06-22

    An adaptive architecture method with feedback control for an intelligent agent provides for adaptively integrating reflexive and deliberative responses to a stimulus according to a goal. An adaptive architecture method with feedback control for multiple intelligent agents provides for coordinating and adaptively integrating reflexive and deliberative responses to a stimulus according to a goal. Re-programming of the adaptive architecture is through a nexus which coordinates reflexive and deliberator components.

  10. Point kinetics calculations with fully coupled thermal fluids reactivity feedback

    SciTech Connect (OSTI)

    Zhang, H.; Zou, L.; Andrs, D.; Zhao, H.; Martineau, R.

    2013-07-01

    The point kinetics model has been widely used in the analysis of the transient behavior of a nuclear reactor. In the traditional nuclear reactor system safety analysis codes such as RELAP5, the reactivity feedback effects are calculated in a loosely coupled fashion through operator splitting approach. This paper discusses the point kinetics calculations with the fully coupled thermal fluids and fuel temperature feedback implemented into the RELAP-7 code currently being developed with the MOOSE framework. (authors)

  11. Signal Flows in Non-Markovian Linear Quantum Feedback Networks

    E-Print Network [OSTI]

    Re-Bing Wu; Jing Zhang; Yu-xi Liu; Tzyh-Jong Tarn

    2014-12-17

    Enabled by rapidly developing quantum technologies, it is possible to network quantum systems at a much larger scale in the near future. To deal with non-Markovian dynamics that is prevalent in solid-state devices, we propose a general transfer function based framework for modeling linear quantum networks, in which signal flow graphs are applied to characterize the network topology by flow of quantum signals. We define a noncommutative ring $\\mathbb{D}$ and use its elements to construct Hamiltonians, transformations and transfer functions for both active and passive systems. The signal flow graph obtained for direct and indirect coherent quantum feedback systems clearly show the feedback loop via bidirectional signal flows. Importantly, the transfer function from input to output field is derived for non-Markovian quantum systems with colored inputs, from which the Markovian input-output relation can be easily obtained as a limiting case. Moreover, the transfer function possesses a symmetry structure that is analogous to the well-know scattering transformation in \\sd picture. Finally, we show that these transfer functions can be integrated to build complex feedback networks via interconnections, serial products and feedback, which may include either direct or indirect coherent feedback loops, and transfer functions between quantum signal nodes can be calculated by the Riegle's matrix gain rule. The theory paves the way for modeling, analyzing and synthesizing non-Markovian linear quantum feedback networks in the frequency-domain.

  12. A Framework for Measurement Feedback to Improve Decision-Making in Mental Health

    E-Print Network [OSTI]

    2010-01-01

    Information Technology Architecture Versus Measurementabout the information technology architecture of a feedback

  13. A Study on the Role of Force Feedback for Teleoperation of Industrial Overhead Crane

    E-Print Network [OSTI]

    Ryu, Jee-Hwan

    A Study on the Role of Force Feedback for Teleoperation of Industrial Overhead Crane Ildar://robot.kut.ac.kr Abstract. In this paper, a study on the role of force feedback for tele- operation of industrial overhead types of force feedback signals which can reduce sway motion in industrial crane. First, force feedback

  14. POISONED FEEDBACK: THE IMPACT OF MALICIOUS USERS IN CLOSED-LOOP MULTIUSER MIMO SYSTEMS

    E-Print Network [OSTI]

    Swindlehurst, A. Lee

    POISONED FEEDBACK: THE IMPACT OF MALICIOUS USERS IN CLOSED-LOOP MULTIUSER MIMO SYSTEMS Amitav systems based on malicious feedback of CSI. In particular, we examine malicious or poisoned feedback of the trans- mitter are listed in Sec. 3. Numerical results that depict the impact of poisoned feedback

  15. AMEAerospace & Mechanical

    E-Print Network [OSTI]

    Wang, Hai

    , emerging fuel cell technolo- gies, computational fluid mechanics, ground vehicle aerodynamics, combustion students develop problem solving skills in the areas of mechanics, thermody- namics, fluid mechanics, heat advance our understanding of such areas as continuum and particulate fluid mechanics, flight mechanics

  16. Bohmian Mechanics

    E-Print Network [OSTI]

    Detlef Duerr; Sheldon Goldstein; Roderich Tumulka; Nino Zanghi

    2009-03-15

    Bohmian mechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmian mechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmian mechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.

  17. Gas Feedback on Stellar Bar Evolution

    E-Print Network [OSTI]

    Ingo Berentzen; Isaac Shlosman; Inma Martinez-Valpuesta; Clayton Heller

    2007-05-27

    We analyze evolution of live disk-halo systems in the presence of various gas fractions, f_gas less than 8% in the disk. We addressed the issue of angular momentum (J) transfer from the gas to the bar and its effect on the bar evolution. We find that the weakening of the bar, reported in the literature, is not related to the J-exchange with the gas, but is caused by the vertical buckling instability in the gas-poor disks and by a steep heating of a stellar velocity dispersion by the central mass concentration (CMC) in the gas-rich disks. The gas has a profound effect on the onset of the buckling -- larger f_gas brings it forth due to the more massive CMCs. The former process leads to the well-known formation of the peanut-shaped bulges, while the latter results in the formation of progressively more elliptical bulges, for larger f_gas. The subsequent (secular) evolution of the bar differs -- the gas-poor models exhibit a growing bar while gas-rich models show a declining bar whose vertical swelling is driven by a secular resonance heating. The border line between the gas-poor and -rich models lies at f_gas ~ 3% in our models, but is model-dependent and will be affected by additional processes, like star formation and feedback from stellar evolution. The overall effect of the gas on the evolution of the bar is not in a direct J transfer to the stars, but in the loss of J by the gas and its influx to the center that increases the CMC. The more massive CMC damps the vertical buckling instability and depopulates orbits responsible for the appearance of peanut-shaped bulges. The action of resonant and non-resonant processes in gas-poor and gas-rich disks leads to a converging evolution in the vertical extent of the bar and its stellar dispersion velocities, and to a diverging evolution in the bulge properties.

  18. Volume 25 November 5, 2014 3461 Emergent mechanics of biological structures

    E-Print Network [OSTI]

    Dumont, Sophie

    (feedback loops) between them. We contrast these to the mechanics of static structures that are frozenVolume 25 November 5, 2014 3461 Emergent mechanics of biological structures Sophie Dumonta of Bioengineering, Stanford University, Stanford, CA 94305-4125 ABSTRACT Mechanical force organizes life at all

  19. ULTRAFAST OUTFLOWS: GALAXY-SCALE ACTIVE GALACTIC NUCLEUS FEEDBACK

    SciTech Connect (OSTI)

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2013-01-20

    We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two-phase ISM consisting of dense clouds embedded in a tenuous, hot, hydrostatic medium. The outflow floods through the intercloud channels, sweeps up the hot ISM, and ablates and disperses the dense clouds. The momentum of the UFO is primarily transferred to the dense clouds via the ram pressure in the channel flow, and the wind-blown bubble evolves in the energy-driven regime. Any dependence on UFO opening angle disappears after the first interaction with obstructing clouds. On kpc scales, therefore, feedback by UFOs operates similarly to feedback by relativistic AGN jets. Negative feedback is significantly stronger if clouds are distributed spherically rather than in a disk. In the latter case, the turbulent backflow of the wind drives mass inflow toward the central black hole. Considering the common occurrence of UFOs in AGNs, they are likely to be important in the cosmological feedback cycles of galaxy formation.

  20. Coherent versus measurement feedback: Linear systems theory for quantum information

    E-Print Network [OSTI]

    Naoki Yamamoto

    2014-10-10

    To control a quantum system via feedback, we generally have two options in choosing control scheme. One is the coherent feedback, which feeds the output field of the system, through a fully quantum device, back to manipulate the system without involving any measurement process. The other one is the measurement-based feedback, which measures the output field and performs a real-time manipulation on the system based on the measurement results. Both schemes have advantages/disadvantages, depending on the system and the control goal, hence their comparison in several situation is important. This paper considers a general open linear quantum system with the following specific control goals; back-action evasion (BAE), generation of a quantum non-demolished (QND) variable, and generation of a decoherence-free subsystem (DFS), all of which have important roles in quantum information science. Then some no-go theorems are proven, clarifying that those goals cannot be achieved by any measurement-based feedback control. On the other hand it is shown that, for each control goal, there exists a coherent feedback controller accomplishing the task. The key idea to obtain all the results is system theoretic characterizations of BAE, QND, and DFS in terms of controllability and observability properties or transfer functions of linear systems, which are consistent with their standard definitions.

  1. Feedback effects of aspherical supernovae explosions on galaxies

    E-Print Network [OSTI]

    Bekki, Kenji; Tsujimoto, Takuji

    2012-01-01

    We investigate how explosions of aspherical supernovae (A-SNe) can influence star formation histories and chemical evolution of dwarf galaxies by using a new chemodynamical model. We mainly present the numerical results of two comparative models so that the A-SN feedback effects on galaxies can be more clearly seen. SNe originating from stars with masses larger than 30M_sun are A-SNe in the "ASN" model whereas all SNe are spherical ones (S-SNe) in the "SSN" model. Each S-SN and A-SN are assumed to release feedback energy of 10^{51} erg and 10^{52} erg, respectively, and chemical yields and feedback energy of A-SN ejecta depend on angles between the axis of symmetry and the ejection directions. We find that star formation can become at least by a factor of ~3 lower in the ASN model in comparison with the SSN one owing to the more energetic feedback of A-SNe. As a result of this, chemical evolution can proceed very slowly in the ASN model. A-SN feedback effects can play a significant role in the formation of gi...

  2. Feedback in low-mass galaxies in the early Universe

    E-Print Network [OSTI]

    Erb, Dawn K

    2015-01-01

    The formation, evolution and death of massive stars release large quantities of energy and momentum into the gas surrounding the sites of star formation. This process, generically termed 'feedback', inhibits further star formation either by removing gas from the galaxy, or by heating it to temperatures that are too high to form new stars. Observations reveal feedback in the form of galactic-scale outflows of gas in galaxies with high rates of star formation, especially in the early Universe. Feedback in faint, low-mass galaxies probably facilitated the escape of ionizing radiation from galaxies when the Universe was about 500 million years old, so that the hydrogen between galaxies changed from neutral to ionized--the last major phase transition in the Universe.

  3. Position feedback system for volume holographic storage media

    DOE Patents [OSTI]

    Hays, Nathan J. (San Francisco, CA); Henson, James A. (Morgan Hill, CA); Carpenter, Christopher M. (Sunnyvale, CA); Akin, Jr.. William R. (Morgan Hill, CA); Ehrlich, Richard M. (Saratoga, CA); Beazley, Lance D. (San Jose, CA)

    1998-07-07

    A method of holographic recording in a photorefractive medium wherein stored holograms may be retrieved with maximum signal-to noise ratio (SNR) is disclosed. A plurality of servo blocks containing position feedback information is recorded in the crystal and made non-erasable by heating the crystal. The servo blocks are recorded at specific increments, either angular or frequency, depending whether wavelength or angular multiplexing is applied, and each servo block is defined by one of five patterns. Data pages are then recorded at positions or wavelengths enabling each data page to be subsequently reconstructed with servo patterns which provide position feedback information. The method of recording data pages and servo blocks is consistent with conventional practices. In addition, the recording system also includes components (e.g. voice coil motor) which respond to position feedback information and adjust the angular position of the reference angle of a reference beam to maximize SNR by reducing crosstalk, thereby improving storage capacity.

  4. Numerical simulation of optical feedback on a quantum dot lasers

    SciTech Connect (OSTI)

    Al-Khursan, Amin H., E-mail: ameen_2all@yahoo.com [Thi-Qar University, Nassiriya Nanotechnology Research Laboratory (NNRL), Science College (Iraq); Ghalib, Basim Abdullattif [Babylon University, Laser Physics Department, Science College for Women (Iraq); Al-Obaidi, Sabri J. [Al-Mustansiriyah University, Physics Department, Science College (Iraq)

    2012-02-15

    We use multi-population rate equations model to study feedback oscillations in the quantum dot laser. This model takes into account all peculiar characteristics in the quantum dots such as inhomogeneous broadening of the gain spectrum, the presence of the excited states on the quantum dot and the non-confined states due to the presence of wetting layer and the barrier. The contribution of quantum dot groups, which cannot follow by other models, is simulated. The results obtained from this model show the feedback oscillations, the periodic oscillations which evolves to chaos at higher injection current of higher feedback levels. The frequency fluctuation is attributed mainly to wetting layer with a considerable contribution from excited states. The simulation shows that is must be not using simple rate equation models to express quantum dots working at excited state transition.

  5. Comparing resolved-sideband cooling and measurement-based feedback cooling on an equal footing: analytical results in the regime of ground-state cooling

    E-Print Network [OSTI]

    Kurt Jacobs; Hendra I. Nurdin; Frederick W. Strauch; Matthew James

    2015-03-19

    We show that in the regime of ground-state cooling, simple expressions can be derived for the performance of resolved-sideband cooling --- an example of coherent feedback control --- and optimal linear measurement-based feedback cooling for a harmonic oscillator. These results are valid to leading order in the small parameters that define this regime. They provide insight into the origins of the limitations of coherent and measurement-based feedback for linear systems, and the relationship between them. These limitations are not fundamental bounds imposed by quantum mechanics, but are due to the fact that both cooling methods are restricted to use only a linear interaction with the resonator. We compare the performance of the two methods on an equal footing --- that is, for the same interaction strength --- and confirm that coherent feedback is able to make much better use of the linear interaction than measurement-based feedback. We find that this performance gap is caused not by the back-action noise of the measurement but by the projection noise. We also obtain simple expressions for the maximal cooling that can be obtained by both methods in this regime, optimized over the interaction strength.

  6. DRIVING OUTFLOWS WITH RELATIVISTIC JETS AND THE DEPENDENCE OF ACTIVE GALACTIC NUCLEUS FEEDBACK EFFICIENCY ON INTERSTELLAR MEDIUM INHOMOGENEITY

    SciTech Connect (OSTI)

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2012-10-01

    We examine the detailed physics of the feedback mechanism by relativistic active galactic nucleus (AGN) jets interacting with a two-phase fractal interstellar medium (ISM) in the kpc-scale core of galaxies using 29 three-dimensional grid-based hydrodynamical simulations. The feedback efficiency, as measured by the amount of cloud dispersal generated by the jet-ISM interactions, is sensitive to the maximum size of clouds in the fractal cloud distribution but not to their volume filling factor. Feedback ceases to be efficient for Eddington ratios P{sub jet}/L{sub edd} {approx}< 10{sup -4}, although systems with large cloud complexes {approx}> 50 pc require jets of Eddington ratio in excess of 10{sup -2} to disperse the clouds appreciably. Based on measurements of the bubble expansion rates in our simulations, we argue that sub-grid AGN prescriptions resulting in negative feedback in cosmological simulations without a multi-phase treatment of the ISM are good approximations if the volume filling factor of warm-phase material is less than 0.1 and the cloud complexes are smaller than {approx}25 pc. We find that the acceleration of the dense embedded clouds is provided by the ram pressure of the high-velocity flow through the porous channels of the warm phase, flow that has fully entrained the shocked hot-phase gas it has swept up, and is additionally mass loaded by ablated cloud material. This mechanism transfers 10% to 40% of the jet energy to the cold and warm gas, accelerating it within a few 10 to 100 Myr to velocities that match those observed in a range of high- and low-redshift radio galaxies hosting powerful radio jets.

  7. Feedback techniques and SPS Ecloud instabilities - design estimates

    SciTech Connect (OSTI)

    Fox,J.D.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C.; Van Winkle, D.; Byrd, J.; Vay, J-L.; Hofle, W.; Rumolo, G.; de Maria, R.

    2009-05-04

    The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. While the SPS has a coupled-bunch transverse feedback system, control of Ecloud driven motion requires a much wider control bandwidth capable of sensing and controlling motion within each bunched beam. This paper draws beam dynamics data from the measurements and simulations of this SPS instability, and estimates system requirements for a feedback system with 2-4 GS/sec. sampling rates to damp Ecloud-driven transverse motion in the SPS at intensities desired for high-current LHC operation.

  8. Bohmian mechanics contradicts quantum mechanics

    E-Print Network [OSTI]

    Neumaier, Arnold

    Bohmian mechanics contradicts quantum mechanics Arnold Neumaier Institut fur Mathematik, Universit://solon.cma.univie.ac.at/#24;neum/ Abstract. It is shown that, for a harmonic oscillator in the ground state, Bohmian mechanics and quantum mechanics predict values of opposite sign for certain time correlations. The discrepancy can

  9. Emergence and combinatorial accumulation of jittering regimes in spiking oscillators with delayed feedback

    E-Print Network [OSTI]

    Vladimir Klinshov; Leonhard Luecken; Dmitry Shchapin; Vladimir Nekorkin; Serhiy Yanchuk

    2015-12-11

    Interaction via pulses is common in many natural systems, especially neuronal. In this article we study one of the simplest possible systems with pulse interaction: a phase oscillator with delayed pulsatile feedback. When the oscillator reaches a specific state, it emits a pulse, which returns after propagating through a delay line. The impact of an incoming pulse is described by the oscillator's phase reset curve (PRC). In such a system we discover an unexpected phenomenon: for a sufficiently steep slope of the PRC, a periodic regular spiking solution bifurcates with several multipliers crossing the unit circle at the same parameter value. The number of such critical multipliers increases linearly with the delay and thus may be arbitrary large. This bifurcation is accompanied by the emergence of numerous "jittering" regimes with non-equal interspike intervals (ISIs). Each of these regimes corresponds to a periodic solution of the system with a period roughly proportional to the delay. The number of different "jittering" solutions emerging at the bifurcation point increases exponentially with the delay. We describe the combinatorial mechanism that underlies the emergence of such a variety of solutions. In particular, we show how a periodic solution exhibiting several distinct ISIs can imply the existence of multiple other solutions obtained by rearranging of these ISIs. We show that the theoretical results for phase oscillators accurately predict the behavior of an experimentally implemented electronic oscillator with pulsatile feedback.

  10. Feedback from Galaxy Formation: Production and Photodissociation of Primordial Molecular Hydrogen

    E-Print Network [OSTI]

    Massimo Ricotti; Nickolay Y. Gnedin; J. Michael Shull

    2001-09-14

    We use one-dimensional radiative transfer simulations to study the evolution of H_2 gas-phase (H^- catalyzed) formation and photo-dissociation regions in the primordial universe. We find a new positive feedback mechanism capable of producing shells of H_2 in the intergalactic medium, which are optically thick in some Lyman-Werner bands. While these shells exist, this feedback effect is important in reducing the H_2 dissociating background flux and the size of photo-dissociation spheres around each luminous object. The maximum background opacity of the IGM in the H_2 Lyman-Werner bands is \\tau_{H_2} ~ 1-2 for a relic molecular fraction x_{H_2}=2 x 10^{-6}, about 6 times greater than found by Haiman, Abel & Rees. Therefore, the relic molecular hydrogen can decrease the photo-dissociation rate by about an order of magnitude. The problem is relevant to the formation of small primordial galaxies with masses M_{DM} hydrogen cooling to collapse. Alternatively, the universe may have remained dark for several hundred million years after the birth of the first stars, until galaxies with virial temperature T_{vir} > 10^4 K formed.

  11. Quantifying Climate Feedbacks from Abrupt Changes in High-Latitude Trace-Gas Emissions

    SciTech Connect (OSTI)

    Schlosser, Courtney Adam; Walter-Anthony, Katey; Zhuang, Qianlai; Melillo, Jerry

    2013-04-26

    Our overall goal was to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically forced climate warming, and the extent to which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes in the extent of wetlands and lakes, especially thermokarst (thaw) lakes, over the Arctic. Through a coordinated effort of field measurements, model development, and numerical experimentation with an integrated assessment model framework, we have investigated the following hypothesis: There exists a climate-warming threshold beyond which permafrost degradation becomes widespread and thus instigates strong and/or sharp increases in methane emissions (via thermokarst lakes and wetland expansion). These would outweigh any increased uptake of carbon (e.g. from peatlands) and would result in a strong, positive feedback to global climate warming.

  12. Tactile Feedback Can Assist Vision During Mobile Interactions

    E-Print Network [OSTI]

    Hayward, Vincent

    Mobile Interaction, Tactile Feedback ACM Classification Keywords H.5.2 Information Interfaces for a particular tune in a portable music player, see Fig. 1(b). Permission to make digital or hard copies of all was proposed to aid jet pi- lots to become aware of impending stalls [4]. Since then, it has been shown

  13. Motivation Model Results Summary A generative model for feedback networks

    E-Print Network [OSTI]

    White, Douglas R.

    Motivation Model Results Summary A generative model for feedback networks D.R. White1 N. Kejzar2 C #12;Motivation Model Results Summary Outline 1 Motivation An example 2 Model 3 Results Network properties Simulations #12;Motivation Model Results Summary Cycle formation in growing network How to model

  14. Global Warming and Marine Carbon Cycle Feedbacks on

    E-Print Network [OSTI]

    Stocker, Thomas

    Global Warming and Marine Carbon Cycle Feedbacks on Future Atmospheric CO2 Fortunat Joos,* Gian-biogeochemical climate model was used to project at- mospheric carbon dioxide and global warming for scenarios developed by the Intergovernmental Panel on Climate Change. The North Atlantic thermohaline circulation weakens in all global warming

  15. Supervised Learning in Neural Networks without Feedback Networks

    E-Print Network [OSTI]

    Lin, Feng

    Supervised Learning in Neural Networks without Feedback Networks Robert D. Brandt and Feng Lin Abstract In this paper, we study the supervised learning in neural networks. Unlike the com- mon practice (hardware) implementation of arti cial neural networks. This research is supported in part by the National

  16. KEYNOTE PAPER Principles of good assessment and feedback

    E-Print Network [OSTI]

    Azzopardi, Leif

    KEYNOTE PAPER Principles of good assessment and feedback: Theory and practice David Nicol for the theory and practice of assessment in higher education. It presents 10 principles of good assessment underpinning good assessment practice in higher education. In one paper, I (with a colleague) formulated seven

  17. Design and implementation of the feedback systems Web laboratory

    E-Print Network [OSTI]

    Viedma Núñez, Gerardo

    2005-01-01

    This thesis describes the design and implementation of a remote web-based laboratory (WebLab) for MIT's 6.302 Feedback Systems course. The WebLab system proposed consists of a three-tiered architecture where client and ...

  18. Towards Integrated Design of a Robust Feedback Controller and Topography

    E-Print Network [OSTI]

    Van den Hof, Paul

    Towards Integrated Design of a Robust Feedback Controller and Topography Estimator for Atomic Force of the sample topography. Dynamical uncertainties of the system pose a strong limitation on the achievable control bandwidth, and on the accuracy of the estimated topography. This contribution discusses

  19. Distributed Control of Networked Dynamical Systems: Static Feedback,

    E-Print Network [OSTI]

    Dimarogonas, Dimos

    1 Distributed Control of Networked Dynamical Systems: Static Feedback, Integral Action--This paper analyzes distributed control protocols for first- and second-order networked dynamical systems. We systems. The PI controllers successfully attenuate constant disturbances in the network. We prove

  20. Multi-Query Feedback Motion Planning with LQR-Roadmaps

    E-Print Network [OSTI]

    Jackson, Daniel

    Multi-Query Feedback Motion Planning with LQR-Roadmaps Anirudha Majumdar School of Engineering "roadmap", with each segment representing a locally optimal trajectory of the system and a continuous) - and for parameterized finite-time invariance around a trajectory, as well as a "roadmap" construction al- gorithm

  1. Feedback Relationships between New Technology Use and Information Networks

    E-Print Network [OSTI]

    Krivobokova, Tatyana

    Feedback Relationships between New Technology Use and Information Networks: Evidence from Ghana;1 Introduction The introduction of new technologies into farming communities in develop- ing countries has. But farmers interested in using a new technology may not possess all of the relevant information about

  2. Iterated Learning with Human subjects: adding communication and feedback 

    E-Print Network [OSTI]

    Murray, Laura

    2010-11-24

    with no intentional design on behalf of the subject. However, filtering for homonymy was necessary to produce a language that adapted to be learnable by becoming more structured and expressive. What I proposed was to introduce communication and feedback to investigate...

  3. MARKET VOLATILITY AND FEEDBACK EFFECTS FROM DYNAMIC HEDGING1

    E-Print Network [OSTI]

    Frey, Rüdiger

    expression for the transformation of market volatility under the impact of such strategies. It turns outMARKET VOLATILITY AND FEEDBACK EFFECTS FROM DYNAMIC HEDGING1 Rudiger Frey Department of Statistics, University of Bonn, D-53113 Bonn, Germany Alexander Stremme Financial Markets Group, London School

  4. Computational Aspects of Feedback in Neural Wolfgang Maass1*

    E-Print Network [OSTI]

    Koch, Christof

    Computational Aspects of Feedback in Neural Circuits Wolfgang Maass1* , Prashant Joshi1 , Eduardo D. Sontag2 1 Institute for Theoretical Computer Science, Technische Universitaet Graz, Graz, Austria, 2-time computations on continuous input streams, provided that these computations can be carried out with a rapidly

  5. MATH43032/63032, May 2014 Exam, and Feedback

    E-Print Network [OSTI]

    Sidorov, Nikita

    MATH43032/63032, May 2014 Exam, Solutions1 and Feedback Solutions A1. |s i si S = or i si S = and for the least such i, si S S. The Representation Theorem for Rational Consequence Relations: Every ra- tional are more detailed than I would expect in the exam. That's because I want them to also serve an educational

  6. Impact of feedbacks on Chihuahuan desert grasslands: Transience and metastability

    E-Print Network [OSTI]

    Archer, Steven R.

    .e., desertification) directly impacts ca. 250 million people in the developing world and could potentially impact the 2.5 billion people who live in dry lands worldwide [Reynolds et al., 2007]. Desertification is also and albedo accom- panying desertification can significantly impact regional climate with feedbacks

  7. Fire Feedbacks with Vegetation and Alternative Stable States

    E-Print Network [OSTI]

    Beckage, Brian

    landscape composition and that (ii) hurricane disturbances can mediate the frequency of fire that leads frequency. Our results indicate that gradual changes in global climate that influence disturbance frequency.Beckage@uvm.edu Positive feedbacks between vegetation and fire disturbance may lead to nonlinear ecosystem responses

  8. NONLINEAR TIME-INVARIANT FEEDBACK CONTROL OF AN UNDERACTUATED MARINE

    E-Print Network [OSTI]

    Zimmer, Uwe

    NONLINEAR TIME-INVARIANT FEEDBACK CONTROL OF AN UNDERACTUATED MARINE VEHICLE ALONG A STRAIGHT: A nonlinear, closed-loop, time-invariant controller that globally stabilizes an underactuated marine vehicle: Marine systems, nonlinear control, tracking. 1. INTRODUCTION Consider a marine vehicle moving in the hori

  9. POLE PLACEMENT BY STATIC OUTPUT FEEDBACK FOR GENERIC LINEAR SYSTEMS

    E-Print Network [OSTI]

    Eremenko, Alexandre

    POLE PLACEMENT BY STATIC OUTPUT FEEDBACK FOR GENERIC LINEAR SYSTEMS A. EREMENKO AND A. GABRIELOV of such systems, where the real pole placement map is not surjective. It follows that for each system in U, there exists an open set of pole configurations, symmetric with respect to the real line, which cannot

  10. Counterexamples to pole placement by static output feedback

    E-Print Network [OSTI]

    Eremenko, Alexandre

    Counterexamples to pole placement by static output feedback A. Eremenko # and A. Gabrielov + 6 these conditions, there is a non­empty open subset U of such systems, where the real pole placement map is not surjective. It follows that for systems in U , there exist open sets of pole configurations which cannot

  11. Counterexamples to pole placement by static output feedback

    E-Print Network [OSTI]

    Eremenko, Alexandre

    Counterexamples to pole placement by static output feedback A. Eremenko and A. Gabrielov 6 these conditions, there is a non-empty open subset U of such systems, where the real pole placement map is not surjective. It follows that for systems in U, there exist open sets of pole configurations which cannot

  12. POLE PLACEMENT BY STATIC OUTPUT FEEDBACK FOR GENERIC LINEAR SYSTEMS

    E-Print Network [OSTI]

    Eremenko, Alexandre

    POLE PLACEMENT BY STATIC OUTPUT FEEDBACK FOR GENERIC LINEAR SYSTEMS A. EREMENKO # AND A. GABRIELOV of such systems, where the real pole placement map is not surjective. It follows that for each system in U , there exists an open set of pole configurations, symmetric with respect to the real line, which cannot

  13. Static Bifurcation in Mechanical Control Harry G. Kwatny1

    E-Print Network [OSTI]

    Kwatny, Harry G.

    Static Bifurcation in Mechanical Control Systems Harry G. Kwatny1 , Bor-Chin Chang1 , and Shiu static bifurcation. Static bifurcation in feedback systems is linked to degeneracies in the system zero Introduction Many important problems in the operation of technological systems can be interpreted as static

  14. RFI Seeks Feedback on Third-party Maintenance Strategy for AMO...

    Energy Savers [EERE]

    RFI Seeks Feedback on Third-party Maintenance Strategy for AMO's Software Tools RFI Seeks Feedback on Third-party Maintenance Strategy for AMO's Software Tools July 28, 2014 -...

  15. Synthesis and Hardware Implementation of an Unmanned Aerial Vehicle Automatic Landing System Utilizing Quantitative Feedback Theory 

    E-Print Network [OSTI]

    Woodbury, Timothy Daniel

    2014-07-08

    that the control synthesis process using Quantitative Feedback Theory provides robust controllers with generally adequate performance, based on simulation and hardware results. The Quantitative Feedback Theory framework provides a good method for synthesizing...

  16. A Balance Feedback Human Machine Interface for Humanoid Teleoperation in Dynamic Tasks

    E-Print Network [OSTI]

    Souza Ramos, Joao Luiz Almeida

    This paper introduces a novel Balance Feedback Interface (BFI) that addresses the problem of bilateral feedback for teleoperation of humanoid robots. With this new device we expect to enhance robot’s high force manipulation ...

  17. Reduced frequency of concurrent feedback: a test of the guidance hypothesis 

    E-Print Network [OSTI]

    Park, Jin-Hoon

    1999-01-01

    on the computer monitor. Consistent with the guidance hypothesis, the results of Experiment 1 indicated very strong guiding effects of concurrent feedback and strong dependency of the feedback as indicated by extremely poor performance upon withdrawal in retention...

  18. On the Capacity of the Vector MAC and BC with Feedback

    E-Print Network [OSTI]

    Jafar, Syed A.

    On the Capacity of the Vector MAC and BC with Feedback Syed Ali Jafar Qualcomm Incorporated San to scalar MACs and BCs, respectively. We also determine the capacity enhancement due to feedback at high SNR

  19. ADITYA KARNIK: PERFORMANCE OF TCP WITH EXPLICIT RATE FEEDBACK 1 Performance of TCP Congestion Control with Explicit Rate Feedback

    E-Print Network [OSTI]

    Kumar, Anurag

    directly to the individual TCP sources, and study a policy for utilizing this rate information in TCP on this rate feed­ back and a round­trip­time (RTT) estimate. Thus our concern in this paper is to studyADITYA KARNIK: PERFORMANCE OF TCP WITH EXPLICIT RATE FEEDBACK 1 Performance of TCP Congestion

  20. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    SciTech Connect (OSTI)

    Skolski, J. Z. P., E-mail: j.z.p.skolski@utwente.nl; Vincenc Obona, J. [Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Römer, G. R. B. E.; Huis in 't Veld, A. J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2014-03-14

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  1. Mechanical Engineering 1 Mechanical Engineering

    E-Print Network [OSTI]

    Haller, Gary L.

    , for example, in novel gas turbine or electric hybrid vehicles--require that students understand the fundamentals of mechanics, thermodynamics, fluid mechanics, combustion, and materials science. In all members of the next generation of mechanical engineers. To implement this mission, the department adheres

  2. On characterization of robust feedback Nash equilibrium for generalized multi-channel systems

    E-Print Network [OSTI]

    Antsaklis, Panos

    1 On characterization of robust feedback Nash equilibrium for generalized multi-channel systems) On characterization of robust feedback Nash equilibrium for generalized multi-channel systems Getachew K. Befekadu. Specifically, we pro- vide a sufficient condition for the existence of a robust feedback Nash equilibrium when

  3. On characterization of robust feedback Nash equilibrium for generalized multi-channel systems

    E-Print Network [OSTI]

    Gupta, Vijay

    On characterization of robust feedback Nash equilibrium for generalized multi-channel systems condition for the existence of a robust feedback Nash equilibrium when every agent aims to optimize the structure of the game. For such a case, we characterize the robust feedback Nash equilibria via a set

  4. Monolithic amplifier with stable, high resistance feedback element and method for fabricating the same

    DOE Patents [OSTI]

    O`Connor, P.

    1998-08-11

    A monolithic amplifier includes a stable, high resistance feedback circuit and a dynamic bias circuit. The dynamic bias circuit is formed with active elements matched to those in the amplifier and feedback circuit to compensate for variations in the operating and threshold voltages thereby maintaining a stable resistance in the feedback circuit. 11 figs.

  5. Computing and Partitioning Cloud Feedbacks Using Cloud Property Histograms. Part I: Cloud Radiative Kernels

    E-Print Network [OSTI]

    Hartmann, Dennis

    Computing and Partitioning Cloud Feedbacks Using Cloud Property Histograms. Part I: Cloud Radiative 2011) ABSTRACT This study proposes a novel technique for computing cloud feedbacks using histograms integrated cloud feedbacks computed in this manner agree remarkably well with the adjusted change in cloud

  6. Feedforward and Feedback Control Behavior in Helicopter Pilots during a Lateral Reposition Task

    E-Print Network [OSTI]

    Feedforward and Feedback Control Behavior in Helicopter Pilots during a Lateral Reposition Task F Pure feedback and pure open-loop feedforward helicopter pilot models are currently applied for predicting the perfor- mance of pilot-helicopter systems. We argue that feedback models are likely

  7. Is measurement-based feedback still better for quantum control systems?

    E-Print Network [OSTI]

    Guo, Lei

    Is measurement-based feedback still better for quantum control systems? Bo Qi , Lei Guo Key Laboratory of Systems and Control, ISS, Academy of Mathematics and Systems Science, Chinese Academy feedback control of quantum systems: Is measurement-based feedback control still better than open- loop

  8. Stability of an Euler-Bernoulli beam with a nonlinear dynamic feedback system

    E-Print Network [OSTI]

    Arnold, Anton

    Stability of an Euler-Bernoulli beam with a nonlinear dynamic feedback system M. Mileti´ca , D. St to a nonlinear dynamic feedback system. This setup comprises nonlinear dynamic boundary controllers satisfying with the interaction of the Euler-Bernoulli beam (1.1) - (1.3) with a dynamic nonlinear feedback system. In particular

  9. The Temporal "Sweet Spot" for Feedback Presentation in Information-Integration Category Learning

    E-Print Network [OSTI]

    Maddox, W. Todd

    . Maddox, W.T., Ashby, F.G., & Bohil, C.J. (2003). Delayed feedback effects on rule-based and information. Wickens, J., & Kotter, R. (1995). Cellular models of reinforcement. In Houk, J.C., Davis, J.L., & Beiser. Examined RB and II learning with different feedback delay intervals -0ms, 500ms and 1000ms delays Feedback

  10. Bohmian mechanics contradicts quantum mechanics

    E-Print Network [OSTI]

    Arnold Neumaier

    2000-02-16

    It is shown that, for a harmonic oscillator in the ground state, Bohmian mechanics and quantum mechanics predict values of opposite sign for certain time correlations. The discrepancy can be explained by the fact that Bohmian mechanics has no natural way to accomodate the Heisenberg picture, since the local expectation values that define the beables of the theory depend on the Heisenberg time being used to define the operators. Relations to measurement are discussed, too, and shown to leave no loophole for claiming that Bohmian mechanics reproduces all predictions of quantum mechanics exactly.

  11. Reputation, Trust, & Rebates: How Online Markets Can Improve Their Feedback Mechanisms

    E-Print Network [OSTI]

    Li, Lingfang Ivy

    2006-01-01

    ? B }. 2. The seller chooses to rebate r or not, where r >seller’s actions set is {Rebate(R S ), N oRebate(N R S )}.Reputation, Trust, and Rebates: How Online Auction Markets

  12. Implementation of mechanical, electrical, and feedback control systems in unmanned aerial vehicles

    E-Print Network [OSTI]

    Tan, Derrick (Derrick Chi-Ho)

    2006-01-01

    The thesis objective was to design an unmanned aerial vehicle that was capable of stable, autonomous flight. A fixed wing aircraft was chosen to simplify some of the flight characteristics and avoid some of the challenges ...

  13. Reputation, Trust, & Rebates: How Online Markets Can Improve Their Feedback Mechanisms

    E-Print Network [OSTI]

    Li, Lingfang Ivy

    2006-01-01

    February 2006. L. Cabral. The economics of reputation anddraft, September 2005. L. Cabral and A. Horta¸ su. Thes reputation pro?le). As Cabral (2005) summarizes, typical

  14. Complex Dynamics and Synchronization of Delayed-Feedback Nonlinear Oscillators

    E-Print Network [OSTI]

    Thomas E. Murphy; Adam B. Cohen; Bhargava Ravoori; Karl R. B. Schmitt; Anurag V. Setty; Francesco Sorrentino; Caitlin R. S. Williams; Edward Ott; Rajarshi Roy

    2009-09-22

    We describe a flexible and modular delayed-feedback nonlinear oscillator that is capable of generating a wide range of dynamical behaviours, from periodic oscillations to high-dimensional chaos. The oscillator uses electrooptic modulation and fibre-optic transmission, with feedback and filtering implemented through real-time digital-signal processing. We consider two such oscillators that are coupled to one another, and we identify the conditions under which they will synchronize. By examining the rates of divergence or convergence between two coupled oscillators, we quantify the maximum Lyapunov exponents or transverse Lyapunov exponents of the system, and we present an experimental method to determine these rates that does not require a mathematical model of the system. Finally, we demonstrate a new adaptive control method that keeps two oscillators synchronized even when the coupling between them is changing unpredictably.

  15. Modeling mutual feedback between users and recommender systems

    E-Print Network [OSTI]

    Zeng, An; Medo, Matus; Zhang, Yi-Cheng

    2015-01-01

    Recommender systems daily influence our decisions on the Internet. While considerable attention has been given to issues such as recommendation accuracy and user privacy, the long-term mutual feedback between a recommender system and the decisions of its users has been neglected so far. We propose here a model of network evolution which allows us to study the complex dynamics induced by this feedback, including the hysteresis effect which is typical for systems with non-linear dynamics. Despite the popular belief that recommendation helps users to discover new things, we find that the long-term use of recommendation can contribute to the rise of extremely popular items and thus ultimately narrow the user choice. These results are supported by measurements of the time evolution of item popularity inequality in real systems. We show that this adverse effect of recommendation can be tamed by sacrificing part of short-term recommendation accuracy.

  16. EFFECTS OF DUST FEEDBACK ON VORTICES IN PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Fu, Wen; Liang, Edison; Li, Hui; Li, Shengtai; Lubow, Stephen

    2014-11-10

    We carried out two-dimensional, high-resolution simulations to study the effect of dust feedback on the evolution of vortices induced by massive planets in protoplanetary disks. Various initial dust to gas disk surface density ratios (0.001-0.01) and dust particle sizes (Stokes number 4 × 10{sup –4}-0.16) are considered. We found that while dust particles migrate inward, vortices are very effective at collecting them. When dust density becomes comparable to gas density within the vortex, a dynamical instability is excited and it alters the coherent vorticity pattern and destroys the vortex. This dust feedback effect is stronger with a higher initial dust/gas density ratio and larger dust grain. Consequently, we found that the disk vortex lifetime can be reduced up to a factor of 10. We discuss the implications of our findings on the survivability of vortices in protoplanetary disks and planet formation.

  17. The pointer basis and the feedback stabilization of quantum systems

    E-Print Network [OSTI]

    L. Li; A. Chia; H. M. Wiseman

    2014-11-19

    The dynamics for an open quantum system can be `unravelled' in infinitely many ways, depending on how the environment is monitored, yielding different sorts of conditioned states, evolving stochastically. In the case of ideal monitoring these states are pure, and the set of states for a given monitoring forms a basis (which is overcomplete in general) for the system. It has been argued elsewhere [D. Atkins et al., Europhys. Lett. 69, 163 (2005)] that the `pointer basis' as introduced by Zurek and Paz [Phys. Rev. Lett 70, 1187(1993)], should be identified with the unravelling-induced basis which decoheres most slowly. Here we show the applicability of this concept of pointer basis to the problem of state stabilization for quantum systems. In particular we prove that for linear Gaussian quantum systems, if the feedback control is assumed to be strong compared to the decoherence of the pointer basis, then the system can be stabilized in one of the pointer basis states with a fidelity close to one (the infidelity varies inversely with the control strength). Moreover, if the aim of the feedback is to maximize the fidelity of the unconditioned system state with a pure state that is one of its conditioned states, then the optimal unravelling for stabilizing the system in this way is that which induces the pointer basis for the conditioned states. We illustrate these results with a model system: quantum Brownian motion. We show that even if the feedback control strength is comparable to the decoherence, the optimal unravelling still induces a basis very close to the pointer basis. However if the feedback control is weak compared to the decoherence, this is not the case.

  18. Feedback-Controlled LED Photobioreactor for Photophysiological Studies of Cyanobacteria

    SciTech Connect (OSTI)

    Melnicki, Matthew R.; Pinchuk, Grigoriy E.; Hill, Eric A.; Kucek, Leo A.; Stolyar, Sergey; Fredrickson, Jim K.; Konopka, Allan; Beliaev, Alex S.

    2013-04-09

    A custom photobioreactor (PBR) was designed to enable automatic light adjustments using computerized feedback control. A black anodized aluminum enclosure, constructed to surround the borosilicate reactor vessel, prevents the transmission of ambient light and serves as a mount for arrays of light-emitting diodes (LEDs). The high-output LEDs provide narrow-band light of either 630 or 680 nm for preferential excitation of the cyanobacterial light-harvesting pigments, phycobilin or chlorophyll a, respectively. Custom developed software BioLume provides automatic control of optical properties and a computer feedback loop can automatically adjust the incident irradiance as necessary to maintain a fixed transmitted light through the culture, based on user-determined set points. This feedback control serves to compensate for culture dynamics which have optical effects, (e.g., changing cell density, pigment adaptations) and thus can determine the appropriate light conditions for physiological comparisons or to cultivate light-sensitive strains, without prior analyses. The LED PBR may also be controlled as a turbidostat, using a feedback loop to continuously adjust the rate of media-dilution based on the transmitted light measurements, with a fast and precise response. This cultivation system gains further merit as a high-performance analytical device, using non-invasive tools (e.g., dissolved gas sensors, online mass spectrometry) to automate real-time measurements, thus permitting unsupervised experiments to search for optimal growth conditions, to monitor physiological responses to perturbations, as well as to quantitate photophysiological parameters using an in situ light-saturation response routine.

  19. Single electron beam rf feedback free electron laser

    DOE Patents [OSTI]

    Brau, C.A.; Stein, W.E.; Rockwood, S.D.

    1981-02-11

    A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

  20. The Radiative Feedback of the First Cosmological Objects

    E-Print Network [OSTI]

    Zoltan Haiman; Tom Abel; Martin J. Rees

    1999-03-23

    In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T_vir 10^4 K) collapse. If the small halos host mini-quasars with hard spectra extending to approximately 1 keV, then their X-rays balance the effects of the UVB, the negative feedback does not occur, and reionization can be caused by the small halos.

  1. Compliant mechanisms 

    E-Print Network [OSTI]

    Venkataraghavan, Janarthanan T

    2001-01-01

    and a few mechanisms like a magneto active peristaltic pump, have been designed and tested for the first time using this material. In this mechanism, the pumping action is obtained when a moving magnetic field produces peristaltic waves in the magneto...

  2. Tidal Downsizing Model. IV. Destructive feedback in planets

    E-Print Network [OSTI]

    Nayakshin, Sergei

    2015-01-01

    I argue that feedback is as important to formation of planets as it is to formation of stars and galaxies. Energy released by massive solid cores puffs up pre-collapse gas giant planets, making them vulnerable to tidal disruptions by their host stars. I find that feedback is the ultimate reason for some of the most robust properties of the observed exoplanet populations: the rarity of gas giants at all separations from $\\sim 0.1$ to $\\sim 100$~AU, the abundance of $\\sim 10 M_\\oplus$ cores but dearth of planets more massive than $\\sim 20 M_\\oplus$. Feedback effects can also explain (i) rapid assembly of massive cores at large separations as needed for Uranus, Neptune and the suspected HL Tau planets; (ii) the small core in Jupiter yet large cores in Uranus and Neptune; (iii) the existence of rare "metal monster" planets such as CoRoT-20b, a gas giant made of heavy elements by up to $\\sim 50$\\%.

  3. Commissioning of the IGp Feedback System at DAFNE

    SciTech Connect (OSTI)

    Drago, A.; /Frascati; Fox, J.D.; /SLAC; Teytelman, D.; /Dimtel, Redwood City; Tobiyama, M.; /KEK, Tsukuba

    2011-11-01

    The iGp (Integrated Gigasample Processor) is an innovative digital bunch-by-bunch feedback system developed by a KEK / SLAC / INFN-LNF joint collaboration. The processing unit can sample at 500 MHz and compute the bunch-by-bunch output signal for up to {approx}5000 bunches. The feedback gateware code is implemented inside just one FPGA (Field Programmable Gate Array) chip, a Xilinx Virtex-II. The FPGA implements two banks of 16-tap FIR (Finite Impulse Response) filters. Each filter is realtime programmable through the operator interface. At DA{Phi}NE, the Frascati {Phi}-Factory, two iGp units have been commissioned in the April 2007. The iGp systems have substituted the previous betatron feedback systems. This insertion has been very fast and has shown no problems involving just a substitution of the old, less flexible, digital systems, letting unchanged the baseband analog frontend and backend. The commissioning has been very simple, due to the complete and powerful EPICS operator interface, working well in local and remote operations. The software includes also tools for analyzing post processor data. A description of the commissioning with the operations done is reported.

  4. Simulations of momentum feedback by black hole winds

    E-Print Network [OSTI]

    Nayakshin, Sergei

    2009-01-01

    The observed super-massive black hole (SMBH) mass -- galaxy velocity dispersion ($M_{\\rm bh} - \\sigma$) correlation may be established when winds/outflows from the SMBH drive gas out of the potential wells of classical bulges. Here we present numerical simulations of this process in a static isothermal potential. Simple spherically symmetric models of SMBH feedback at the Eddington luminosity can successfully explain the $M_{\\rm bh} - \\sigma$ and nuclear cluster mass $M_{\\rm NC}-\\sigma$ correlations, as well as why larger bulges host SMBHs while smaller ones host nuclear star clusters. However these models do not specify how SMBHs feed on infalling gas whilst simultaneously producing feedback that drives gas out of the galaxy. More complex models with rotation and/or anisotropic feedback allow SMBHs to feed via a disc or regions not exposed to SMBH winds, but in these more realistic cases it is not clear why a robust $M_{\\rm bh} - \\sigma$ relation should be established. In fact, some of the model predictions ...

  5. The Impact of Galactic Feedback on the Circumgalactic Medium

    E-Print Network [OSTI]

    Suresh, Joshua; Vogelsberger, Mark; Genel, Shy; Torrey, Paul; Sijacki, Debora; Springel, Volker; Hernquist, Lars

    2015-01-01

    Galactic feedback strongly affects the way galactic environments are enriched. We examine this connection by performing a suite of cosmological hydrodynamic simulations, exploring a range of parameters based on the galaxy formation model developed in Vogelsberger et al. 2013 (henceforth V13). We examine the effects of AGN feedback, wind mass loading, wind specific energy, and wind metal-loading on the properties of the circumgalactic medium (CGM) of galaxies with $M_\\text{halo} > 10^{11} M_\\odot$. Note that while the V13 model was tuned to match observations including the stellar mass function, no explicit tuning was done for the CGM. The wind energy per unit outflow mass has the most significant effect on the CGM enrichment. High energy winds launch metals far beyond the virial radius. AGN feedback also has a significant effect, but only at $z < 3$. We compare to high redshift HI and CIV observations. All our simulations produce the observed number of Damped Lyman-$\\alpha$ Absorbers. At lower column densi...

  6. MECHANICAL ENGINEERING What is Mechanical

    E-Print Network [OSTI]

    power plant energy conversion and generating systems; design, development, and manufactureof consumer of the broadest engineering fields. Mechanical engineers are found in virtually all productive industries, from

  7. Mechanical memory

    DOE Patents [OSTI]

    Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Alburquerque, NM); Baker, Michael S. (Albuquerque, NM)

    2006-08-15

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  8. Mechanical memory

    DOE Patents [OSTI]

    Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Albuquerque, NM); Baker, Michael S. (Albuquerque, NM)

    2006-05-16

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  9. A tale of two feedbacks: Star formation in the host galaxies of radio AGNs

    SciTech Connect (OSTI)

    Karouzos, Marios; Im, Myungshin; Jeon, Yiseul; Kim, Ji Hoon [CEOU-Astronomy Program, Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul (Korea, Republic of); Trichas, Markos [Airbus Defence and Space, Gunnels Wood Road, Stevenage SG1 2AS (United Kingdom); Goto, Tomo [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Malkan, Matt [Division of Astronomy and Astrophysics, 3-714 UCLA, CA 90095-1547 (United States); Ruiz, Angel [Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, 411 007 Pune (India); Lee, Hyung Mok; Kim, Seong Jin [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul (Korea, Republic of); Oi, Nagisa; Matsuhara, Hideo; Takagi, Toshinobu; Murata, K.; Wada, Takehiko; Wada, Kensuke [Institute of Space and Astronautical Science, JAXA, Yoshino-dai 3-1-1, Sagamihara, Kanagawa 229-8510 (Japan); Shim, Hyunjin [Department of Earth Science Education, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Hanami, Hitoshi [Physics Section, Faculty of Humanities, Iwate University, Ueda 3 chome, 18-34 Morioka, Morioka, Iwate 020-8550 (Japan); Serjeant, Stephen; White, Glenn J., E-mail: mkarouzos@astro.snu.ac.kr [Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes (United Kingdom); and others

    2014-04-01

    Several lines of argument support the existence of a link between activity at the nuclei of galaxies, in the form of an accreting supermassive black hole, and star formation activity in these galaxies. Radio jets have long been argued to be an ideal mechanism that allows active galactic nuclei (AGNs) to interact with their host galaxies and affect star formation. We use a sample of radio sources in the North Ecliptic Pole (NEP) field to study the nature of this putative link, by means of spectral energy distribution (SED) fitting. We employ the excellent spectral coverage of the AKARI infrared space telescope and the rich ancillary data available in the NEP to build SEDs extending from UV to far-IR wavelengths. We find a significant AGN component in our sample of relatively faint radio sources (feedback process in the same sample. We discuss the possible suppression of star formation, but not total quenching, in systems with strong radio jets, that supports the maintenance nature of feedback from radio AGN jets.

  10. Basal-subtype and MEK-Pl3K feedback signaling determine susceptibility of breast cancer cells to MEK inhibition

    SciTech Connect (OSTI)

    Mirzoeva, Olga K.; Das, Debopriya; Heiser, Laura M.; Bhattacharya, Sanchita; Siwak, Doris; Gendelman, Rina; Bayani, Nora; Wang, Nicholas J.; Neve, Richard M.; Knight, Zachary; Feiler, Heidi S.; Gascard, Philippe; Parvin, Bahram; Spellman, Paul T.; Shokat, Kevan M.; Wyrobek, Andrew J.; Bissell, Mina J.; McCormick, Frank; Kuo, Wen-Lin; Mills, Gordon B.; Gray, Joe W.; Korn, W. Michael

    2009-01-23

    Specific inhibitors of MEK have been developed that efficiently inhibit the oncogenic RAF-MEK-ERK pathway. We employed a systems-based approach to identify breast cancer subtypes particularly susceptible to MEK inhibitors and to understand molecular mechanisms conferring resistance to such compounds. Basal-type breast cancer cells were found to be particularly susceptible to growth-inhibition by small-molecule MEK inhibitors. Activation of the PI3 kinase pathway in response to MEK inhibition through a negative MEK-EGFR-PI3 kinase feedback loop was found to limit efficacy. Interruption of this feedback mechanism by targeting MEK and PI3 kinase produced synergistic effects, including induction of apoptosis and, in some cell lines, cell cycle arrest and protection from apoptosis induced by proapoptotic agents. These findings enhance our understanding of the interconnectivity of oncogenic signal transduction circuits and have implications for the design of future clinical trials of MEK inhibitors in breast cancer by guiding patient selection and suggesting rational combination therapies.

  11. Essays on Macroeconomics and Oil

    E-Print Network [OSTI]

    CAKIR, NIDA

    2013-01-01

    Oil Production . . . . . . . . . . . . . . . . . . . . . . . . . . .Oil Production in Venezuela and Mexico . . . . . . . . . .Oil Production and Productivity in Venezuela and

  12. Essays on Macroeconomics and Oil

    E-Print Network [OSTI]

    CAKIR, NIDA

    2013-01-01

    is described below. Data Crude oil production data is fromproductivity measure is crude oil production per worker, andwhich is measured as crude oil production per worker, is

  13. Say's Law and modern macroeconomics 

    E-Print Network [OSTI]

    Van Allen, Laurel Cameron

    2013-02-22

    Many economists have debated the interpretation of what is known as "Say's Law of markets"; it has been the subject of controversy for two centuries. Jean Baptiste Say describes Say's Law by noting that the "success of ...

  14. Essays on Macroeconomics and Oil

    E-Print Network [OSTI]

    CAKIR, NIDA

    2013-01-01

    the Oil Industry . . . . . . . . . . . . . . . . . . . . . .in the Venezuelan Oil Industry . . . . . . . . . . . . .and Productivity: Evidence from the Oil Industry . .

  15. Essays in Macroeconomics and Finance

    E-Print Network [OSTI]

    Khramov, Vadim

    2013-01-01

    economies. ” Journal of Finance 39, pages 77-92. Vasicek,Interest Rate. ” Journal of Finance, Vol. 47, No. 3 Chernov,of Economics. B.A. (Finance), Higher School of Economics.

  16. Essays on finance and macroeconomics

    E-Print Network [OSTI]

    Di Tella, Sebastian T. (Sebastian Tariacuri)

    2013-01-01

    This thesis studies the role of the financial system in the amplification and propagation of business cycles. Chapter 1 studies the origin and propagation of balance sheet recessions. I first show that in standard models ...

  17. Essays on Macroeconomics and Oil

    E-Print Network [OSTI]

    CAKIR, NIDA

    2013-01-01

    application to Productivity Measurement in the US Automobileand Mevlyn A. Fuss, ”Productivity Measurement Using Capitalprofitability productivity growth measurement: an integrated

  18. Essays on Macroeconomics and Oil

    E-Print Network [OSTI]

    CAKIR, NIDA

    2013-01-01

    Oil Production in Venezuela and Mexico . . . . . . . . . .and Productivity in Venezuela and Mexico . . . . . . . . OilEllner, ”Organized Labor in Venezuela 1958-1991: Behavior

  19. Essays on Macroeconomics and Oil

    E-Print Network [OSTI]

    CAKIR, NIDA

    2013-01-01

    Venezuelan Oil Industry Total Wells Drilled and InvestmentWells Drilled and Investment in the Venezuelan Oil Industryopenness of the oil sector to foreign investment contributes

  20. Star Formation in Disk Galaxies. III. Does stellar feedback result in cloud death?

    E-Print Network [OSTI]

    Tasker, Elizabeth J; Pudritz, Ralph

    2015-01-01

    Stellar feedback, star formation and gravitational interactions are major controlling forces in the evolution of Giant Molecular Clouds (GMCs). To explore their relative roles, we examine the properties and evolution of GMCs forming in an isolated galactic disk simulation that includes both localised thermal feedback and photoelectric heating. The results are compared with the three previous simulations in this series which consists of a model with no star formation, star formation but no form of feedback and star formation with photoelectric heating in a set with steadily increasing physical effects. We find that the addition of localised thermal feedback greatly suppresses star formation but does not destroy the surrounding GMC, giving cloud properties closely resembling the run in which no stellar physics is included. The outflows from the feedback reduce the mass of the cloud but do not destroy it, allowing the cloud to survive its stellar children. This suggests that weak thermal feedback such as the low...

  1. Weak Measurement and Feedback in Superconducting Quantum Circuits

    E-Print Network [OSTI]

    K. W. Murch; R. Vijay; I. Siddiqi

    2015-07-16

    We describe the implementation of weak quantum measurements in superconducting qubits, focusing specifically on transmon type devices in the circuit quantum electrodynamics architecture. To access this regime, the readout cavity is probed with on average a single microwave photon. Such low-level signals are detected using near quantum-noise-limited superconducting parametric amplifiers. Weak measurements yield partial information about the quantum state, and correspondingly do not completely project the qubit into an eigenstate. As such, we use the measurement record to either sequentially reconstruct the quantum state at a given time, yielding a quantum trajectory, or to close a direct quantum feedback loop, stabilizing Rabi oscillations indefinitely.

  2. On Optimal Feedback Control for Stationary Linear Systems

    SciTech Connect (OSTI)

    Russell, David L., E-mail: russell@math.vt.ed [Virginia Tech, Department of Mathematics (United States)

    2010-04-15

    We study linear-quadratic optimal control problems for finite dimensional stationary linear systems AX+BU=Z with output Y=CX+DU from the viewpoint of linear feedback solution. We interpret solutions in relation to system robustness with respect to disturbances Z and relate them to nonlinear matrix equations of Riccati type and eigenvalue-eigenvector problems for the corresponding Hamiltonian system. Examples are included along with an indication of extensions to continuous, i.e., infinite dimensional, systems, primarily of elliptic type.

  3. Weak Measurement and Feedback in Superconducting Quantum Circuits

    E-Print Network [OSTI]

    K. W. Murch; R. Vijay; I. Siddiqi

    2015-07-28

    We describe the implementation of weak quantum measurements in superconducting qubits, focusing specifically on transmon type devices in the circuit quantum electrodynamics architecture. To access this regime, the readout cavity is probed with on average a single microwave photon. Such low-level signals are detected using near quantum-noise-limited superconducting parametric amplifiers. Weak measurements yield partial information about the quantum state, and correspondingly do not completely project the qubit into an eigenstate. As such, we use the measurement record to either sequentially reconstruct the quantum state at a given time, yielding a quantum trajectory, or to close a direct quantum feedback loop, stabilizing Rabi oscillations indefinitely.

  4. Ignition feedback regenerative free electron laser (FEL) amplifier

    DOE Patents [OSTI]

    Kim, Kwang-Je (Burr Ridge, IL); Zholents, Alexander (Walnut Creek, CA); Zolotorev, Max (Oakland, CA)

    2001-01-01

    An ignition feedback regenerative amplifier consists of an injector, a linear accelerator with energy recovery, and a high-gain free electron laser amplifier. A fraction of the free electron laser output is coupled to the input to operate the free electron laser in the regenerative mode. A mode filter in this loop prevents run away instability. Another fraction of the output, after suitable frequency up conversion, is used to drive the photocathode. An external laser is provided to start up both the amplifier and the injector, thus igniting the system.

  5. Convection feedbacks in a super-parameterization GCM

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortal ControllingConvection feedbacks in a

  6. On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling On-Board Measurement of...

  7. An Investigation into the Benefits of Tactile Feedback for Laparoscopic, Robotic, and Remote Surgery

    E-Print Network [OSTI]

    Wottawa, Christopher Robert

    2013-01-01

    to haptic feedback in robotic surgery. (March 2010 NSFfeedback actuator array for robotic surgery or simulation.conventional versus robotic approach—a comparative study.

  8. EVALUATION OF VOLUMETRIC THRESHOLD STRAIN CONSIDERING NOISY FEEDBACK SIGNALS FROM SIMPLE SHEAR DEVICE

    E-Print Network [OSTI]

    Schoenberg, Frederic Paik (Rick)

    EVALUATION OF VOLUMETRIC THRESHOLD STRAIN CONSIDERING NOISY FEEDBACK SIGNALS FROM SIMPLE SHEAR 90095 #12;set to illustrate how the volumetric threshold shear strain can be evaluated in consideration

  9. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    ScienceCinema (OSTI)

    Norris, Joe [Scripps Institution of Oceanography, University of California, San Diego, California, USA

    2010-09-01

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  10. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    SciTech Connect (OSTI)

    Norris, Joe [Scripps Institution of Oceanography, University of California, San Diego, California, USA

    2010-05-12

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  11. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    SciTech Connect (OSTI)

    Norris, Joel (Scripps Institution of Oceanography, UC San Diego) [Scripps Institution of Oceanography, UC San Diego

    2010-05-10

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  12. Fractofusion mechanism

    SciTech Connect (OSTI)

    Yasui, K. . Dept. of Physics)

    1992-11-01

    In this paper, the fractofusion mechanism of cold fusion is investigated theoretically. The conditions necessary for fractofusion during the absorption of deuterium atoms by palladium specimens (the condition of so-called cold fusion experiments) is clarified, including crack generation at grain boundaries, the high orientation angle of grains, rapid crack formation, the increase of electrical resistance around a crack, the large width of cracks, and the generation of many cracks. The origin and quantity of the electrical field inside cracks in the conductor are also clarified. By the fractofusion mechanism, the experimental facts that neutron emissions are observed in bursts, that sometimes they coincide with the deformation of a palladium specimen, and that in many experiments excess neutrons were not observed are qualitatively explained. The upper limit of the total fractofusion yields during the absorption of deuterium atoms by palladium specimens are estimated.

  13. Mechanical Engineering ME 3720 FLUID MECHANICS

    E-Print Network [OSTI]

    Panchagnula, Mahesh

    Mechanical Engineering ME 3720 FLUID MECHANICS Pre-requisite: ME 2330 Co-requisite: ME 3210) to develop an understanding of the physical mechanisms and the mathematical models of fluid mechanics of fluid mechanics problems in engineering practice. The basic principles of fluid mechanics

  14. MAKING SENSE: WEAKLY ELECTRIC FISH MODULATE SENSORY FEEDBACK VIA SOCIAL BEHAVIOR AND MOVEMENT

    E-Print Network [OSTI]

    MAKING SENSE: WEAKLY ELECTRIC FISH MODULATE SENSORY FEEDBACK VIA SOCIAL BEHAVIOR AND MOVEMENT. This dissertation examines the role of social behavior and movement for the modulation of electrosensory feedback social grouping and movement can produce higher order modulations (termed `envelopes'), which can have

  15. Vibrotactile Feedback in Steering Wheel Reduces Navigation Errors during GPS-Guided Car Driving

    E-Print Network [OSTI]

    Basdogan, Cagatay

    Vibrotactile Feedback in Steering Wheel Reduces Navigation Errors during GPS-Guided Car Driving feedback displayed through the steering wheel of a car can reduce the perceptual and cognitive load with the GPS-based voice commands. KEYWORDS: vibrotactile, haptics, car navigation systems, GPS, steering wheel

  16. State feedback control of labeled Petri nets with uncertainty in the initial marking

    E-Print Network [OSTI]

    Hadjicostis, Christoforos

    State feedback control of labeled Petri nets with uncertainty in the initial marking Maria Paola feedback controller for a labeled Petri net whose ini- tial marking is known to belong to a given convex vehicles, com- munication networks, and so on. In this paper we deal with the problem of designing a state

  17. Open-Loop Digital Predistortion Using Cartesian Feedback for Adaptive RF Power Amplifier Linearization

    E-Print Network [OSTI]

    Dawson, Joel

    leverage analog Cartesian feedback (CFB) to train a Cartesian look-up table, reducing DSP and power the CFB system does not continuously operate, we overcome the bandwidth limitation traditionally is that it is not robust to variations in process, supply voltage, temperature, and aging effects. Cartesian feedback (CFB

  18. Feedback Can Increase the CapacityCost Function of Discrete Channels with Memory y

    E-Print Network [OSTI]

    Alajaji, Fady

    bound to the capacity­cost func­ tion with feedback (CFB (fi)). The lower bound to CFB (fi) is then shown numerically to exceed the upper bound to CNFB (fi). An upper bound to CFB (fi) is also obtained and feedback capacity­cost functions -- denoted by CNFB (fi) and CFB (fi) respectively -- in order to deter

  19. Hardware Design and Analysis of Statistical Cipher Feedback Mode Using Serial Transfer

    E-Print Network [OSTI]

    Heys, Howard

    to the Ciphertext Queue. SCFB mode is the hybrid of output feedback (OFB) mode and cipher feedback (CFB) mode feeds back ciphertext to the input of the block cipher similar to the conventional CFB mode, except- plementation than conventional CFB mode. An iterative based implementation of the Advanced Encryption Strandard

  20. Tracking Analysis of an LMS Decision Feedback Equalizer for a Wireless Channel

    E-Print Network [OSTI]

    Sharma, Vinod

    Tracking Analysis of an LMS Decision Feedback Equalizer for a Wireless Channel Veeraruna Kavitha varying wireless fading chan- nel, equalized by an LMS Decision Feedback equalizer (DFE). We study how- regressive (AR) process. Then the LMS equalizer and the AR process are jointly approximated by the solution

  1. Using models and satellite observations to evaluate the strength of snow albedo feedback

    E-Print Network [OSTI]

    Using models and satellite observations to evaluate the strength of snow albedo feedback; revised 9 May 2012; accepted 10 May 2012; published 15 June 2012. [1] Snow albedo feedback (SAF to the albedo contrast of snow covered and snow-free land (SNC), and 20% was related to the temperature

  2. Postdoc Opportunity: Feedback, Noise, and Single-Cell Antibiotic Resistance PI: Mary Dunlop, Ph.D.

    E-Print Network [OSTI]

    Dunlop, Mary

    include: · Time-lapse imaging of fluorescent reporters for multidrug resistance in bacteria. · CostPostdoc Opportunity: Feedback, Noise, and Single-Cell Antibiotic Resistance PI: Mary Dunlop, Ph of feedback and stochastic gene regulation related to single-cell antibiotic resistance. Research areas

  3. The Capacity-Cost Function of Discrete Additive Noise Channels with and without Feedback

    E-Print Network [OSTI]

    Wehlau, David

    of discrete channels with memory. Index Terms { Channels with memory, additive noise, capacity-cost functionThe Capacity-Cost Function of Discrete Additive Noise Channels with and without Feedback #3; Fady by investigating the capacity- cost function (C (#12;)) of such additive noise channels without feedback. We

  4. COMPLEX STATIC SKEW-SYMMETRIC OUTPUT FEEDBACK CHRISTOPHER J. HILLAR AND FRANK SOTTILE

    E-Print Network [OSTI]

    Sottile, Frank

    COMPLEX STATIC SKEW-SYMMETRIC OUTPUT FEEDBACK CONTROL CHRISTOPHER J. HILLAR AND FRANK SOTTILE functions using skew-symmetric controllers. This extends work of Helmke, et al., who studied static, give necessary and sufficient conditions for pole placement by static skew-symmetric complex feedback

  5. Some Like it Hot? Thermal Feedback for Mobile Devices Graham Wilson, Martin Halvey, Stephen A. Brewster

    E-Print Network [OSTI]

    Brewster, Stephen

    perception and this is not the focus of this paper. Fundamental HCI research needs to be conducted we focus on in this paper. There are many potential uses for thermal feedback; the following usageSome Like it Hot? Thermal Feedback for Mobile Devices Graham Wilson, Martin Halvey, Stephen A

  6. Can Haptic Feedback Improve the Perception of Self-Motion in Virtual Reality? Anatole Lcuyer1

    E-Print Network [OSTI]

    training), for design (virtual visit of urban or architectural projects) or simply for fun (video games of haptic feedback on the perception of self-motion in virtual reality. Participants were asked to estimate studies the influence of haptic feedback on the user's perception and estimation of the turns' angles. 2

  7. DEFINING AND QUANTIFYING FEEDBACKS IN EARTH'S CLIMATE SYSTEM Stephen E. Schwartz

    E-Print Network [OSTI]

    DEFINING AND QUANTIFYING FEEDBACKS IN EARTH'S CLIMATE SYSTEM Stephen E. Schwartz For presentation.bnl.gov ABSTRACT Feedbacks in Earth's climate system are increasingly being examined to identify processes of climate models to accurately represent the actual climate system and changes due to increases

  8. Coherent Feedback Improved Qubit Initialization in the Dispersive Regime

    E-Print Network [OSTI]

    Luke C. G. Govia; Frank K. Wilhelm

    2015-06-17

    Readout of the state of a superconducting qubit by homodyne detection of the output signal from a dispersively coupled microwave resonator is a common technique in circuit quantum electrodynamics, and is often claimed to be quantum non-demolition (QND) up to the same order of approximation as in the dispersive approximation. However, in this work we show that only in the limit of infinite measurement time is this protocol QND, as the formation of a dressed coherent state in the qubit-cavity system applies an effective rotation to the qubit state. We show how this rotation can be corrected by a coherent operation, leading to improved qubit initialization by measurement and coherent feedback.

  9. Continuous decomposition of quantum measurements via Hamiltonian feedback

    E-Print Network [OSTI]

    Jan Florjanczyk; Todd A. Brun

    2015-04-15

    We characterize the set of generalized quantum measurements that can be decomposed into a continuous measurement process using a stream of probe qubits and a tunable interaction Hamilto- nian. Each probe in the stream interacts weakly with the target quantum system, then is measured projectively in a standard basis. This measurement result is used in a closed feedback loop to tune the interaction Hamiltonian for the next probe. The resulting evolution is a stochastic process with the structure of a one-dimensional random walk. To maintain this structure, and require that at long times the measurement outcomes be independent of the path, the allowed interaction Hamil- tonians must lie in a restricted set, such that the Hamiltonian terms on the target system form a finite dimensional Jordan algebra. This algebraic structure of the interaction Hamiltonians yields a large class of generalized measurements that can be continuously performed by our scheme, and we fully describe this set.

  10. Black hole feedback in the luminous quasar PDS 456

    E-Print Network [OSTI]

    Nardini, E; Gofford, J; Harrison, F A; Risaliti, G; Braito, V; Costa, M T; Matzeu, G A; Walton, D J; Behar, E; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Matt, G; Miller, J M; O'Brien, P T; Stern, D; Turner, T J; Ward, M J

    2015-01-01

    The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband X-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10^46 ergs per second is enough to provide the feedback required by models of black hole and host galaxy co-evolution.

  11. Maxwell's demon in biochemical signal transduction with feedback loop

    E-Print Network [OSTI]

    Sosuke Ito; Takahiro Sagawa

    2015-04-15

    Signal transduction in living cells is vital to maintain life itself, where information transfer in noisy environment plays a significant role. In a rather different context, the recent intensive researches of "Maxwell's demon" - a feedback controller that utilizes information of individual molecules - has led to a unified theory of information and thermodynamics. Here we combine these two streams of researches, and show that the second law of thermodynamics with information reveals the fundamental limit of the robustness of signal transduction against environmental fluctuations. Especially, we found that the degree of robustness is quantitatively characterized by an informational quantity called transfer entropy. Our information-thermodynamic approach is applicable to biological communication inside cells, in which there is no explicit channel coding in contrast to artificial communication. Our result would open up a novel biophysical approach to understand information processing in living systems on the basis of the fundamental information-thermodynamics link.

  12. Feedback regulated induction heater for a flowing fluid

    DOE Patents [OSTI]

    Migliori, Albert (Santa Fe, NM); Swift, Gregory W. (Los Alamos, NM)

    1985-01-01

    A regulated induction heater for heating a stream of flowing fluid to a predetermined desired temperature. The heater includes a radiofrequency induction coil which surrounds a glass tube through which the fluid flows. A heating element consisting of a bundle of approximately 200 stainless steel capillary tubes located within the glass tube couples the output of the induction coil to the fluid. The temperature of the fluid downstream from the heating element is sensed with a platinum resistance thermometer, the output of which is applied to an adjustable proportional and integral feedback control circuit which regulates the power applied to the induction coil. The heater regulates the fluid temperature to within 0.005.degree. C. at a flow rate of 50 cm.sup.3 /second with a response time of less than 0.1 second, and can accommodate changes in heat load up to 1500 watts.

  13. Feedback regulated induction heater for a flowing fluid

    DOE Patents [OSTI]

    Migliori, A.; Swift, G.W.

    1984-06-13

    A regulated induction heater for heating a stream of flowing fluid to a predetermined desired temperature. The heater includes a radiofrequency induction coil which surrounds a glass tube through which the fluid flows. A heating element consisting of a bundle of approximately 200 stainless steel capillary tubes located within the glass tube couples the output of the induction coil to the fluid. The temperature of the fluid downstream from the heating element is sensed with a platinum resistance thermometer, the output of which is applied to an adjustable porportional and integral feedback control circuit which regulates the power applied to the induction coil. The heater regulates the fluid temperature to within 0.005/sup 0/C at a flow rate of 50 cm/sup 3//sec with a response time of less than 0.1 second, and can accommodate changes in heat load up to 1500 watts.

  14. Generalization of neuron network model with delay feedback

    E-Print Network [OSTI]

    Sanjeet Maisnam; R. K. Brojen Singh

    2015-07-16

    We present generalized delayed neural network (DNN) model with positive delay feedback and neuron history. The local stability analysis around trivial local equilibria of delayed neural networks has applied and determine the conditions for the existence of zero root. We develop few innovative delayed neural network models in different dimensions through transformation and extension of some existing models. We found that zero root can have multiplicity two under certain conditions. We further show how the characteristic equation can have zero root and its multiplicity is dependent on the conditions undertaken. Finally, we generalize the neural network of $N$ neurons through which we determine the general form of Jacobian of the linear form and corresponding characteristic equation of the system.

  15. Photo-heating and supernova feedback amplify each other's effect on the cosmic star formation rate

    E-Print Network [OSTI]

    Andreas H. Pawlik; Joop Schaye

    2009-03-17

    Photo-heating associated with reionisation and kinetic feedback from core-collapse supernovae have previously been shown to suppress the high-redshift cosmic star formation rate. Here we investigate the interplay between photo-heating and supernova feedback using a set of cosmological, smoothed particle hydrodynamics simulations. We show that photo-heating and supernova feedback mutually amplify each other's ability to suppress the star formation rate. Our results demonstrate the importance of the simultaneous, non-independent inclusion of these two processes in models of galaxy formation to estimate the strength of the total negative feedback they exert. They may therefore be of particular relevance to semi-analytic models in which the effects of photo-heating and supernova feedback are implicitly assumed to act independently of each other.

  16. Iterative Dense Correspondence Correction Through Bundle Adjustment Feedback-Based Error Detection

    SciTech Connect (OSTI)

    Hess-Flores, M A; Duchaineau, M A; Goldman, M J; Joy, K I

    2009-11-23

    A novel method to detect and correct inaccuracies in a set of unconstrained dense correspondences between two images is presented. Starting with a robust, general-purpose dense correspondence algorithm, an initial pose estimate and dense 3D scene reconstruction are obtained and bundle-adjusted. Reprojection errors are then computed for each correspondence pair, which is used as a metric to distinguish high and low-error correspondences. An affine neighborhood-based coarse-to-fine iterative search algorithm is then applied only on the high-error correspondences to correct their positions. Such an error detection and correction mechanism is novel for unconstrained dense correspondences, for example not obtained through epipolar geometry-based guided matching. Results indicate that correspondences in regions with issues such as occlusions, repetitive patterns and moving objects can be identified and corrected, such that a more accurate set of dense correspondences results from the feedback-based process, as proven by more accurate pose and structure estimates.

  17. The role of water vapor feedback in unperturbed climate variability and global warming

    SciTech Connect (OSTI)

    Hall, A.; Manabe, Syukuro

    1999-08-01

    To understand the role of water vapor feedback in unperturbed surface temperature variability, a version of the Geophysical Fluid Dynamics Laboratory coupled ocean-atmosphere model is integrated for 1,000 yr in two configurations, one with water vapor feedback and one without. To understand the role of water vapor feedback in global warming, two 500-yr integrations were also performed in which CO{sub 2} was doubled in both model configurations. The final surface global warming in the model with water vapor feedback is 3.38 C, while in the one without it is only 1.05 C. However, the model`s water vapor feedback has a larger impact on surface warming in response to a doubling of CO{sub 2} than it does on internally generated, low-frequency, global-mean surface temperature anomalies. Water vapor feedback`s strength therefore depends on the type of temperature anomaly it affects. Finally, the authors compare the local and global-mean surface temperature time series from both unperturbed variability experiments to the observed record. The experiment without water vapor feedback does not have enough global-scale variability to reproduce the magnitude of the variability in the observed global-mean record, whether or not one removes the warming trend observed over the past century. In contrast, the amount of variability in the experiment with water vapor feedback is comparable to that of the global-mean record, provided the observed warming trend is removed. Thus, the authors are unable to simulate the observed levels of variability without water vapor feedback.

  18. Carbon sequestration in peatland: patterns and mechanisms of response to climate change

    E-Print Network [OSTI]

    Carbon sequestration in peatland: patterns and mechanisms of response to climate change L I S A R., 2000; Turunen et al., 2002; Kremenetski et al., 2003). Rates of carbon (C) sequestration (i.e., uptake in the climatic water budget is crucial to predicting potential feedbacks on the global carbon (C) cycle. To gain

  19. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering An experimental methodology is presented for mechanism verification of physics-based prognosis of mechanical damage, such as fatigue. The proposed experimental methodology includes multi-resolution in-situ mechanical testing, advanced imaging analysis, and mechanism

  20. Characterization of feedback Nash equilibria for multi-channel systems via a set of non-fragile

    E-Print Network [OSTI]

    Antsaklis, Panos

    Characterization of feedback Nash equilibria for multi-channel systems via a set of non in Intelligent Systems #12;Characterization of feedback Nash equilibria for multi-channel systems via a set. In such a framework, we char- acterize the feedback Nash equilibria over an infinite-time horizon via a set of non

  1. Optimal design of feedback coils for the control of external modes in tokamaks R. Fitzpatrick and E. P. Yu

    E-Print Network [OSTI]

    Fitzpatrick, Richard

    Optimal design of feedback coils for the control of external modes in tokamaks R. Fitzpatrick and E output feedback control of resistive wall modes in tokamaks Phys. Plasmas 13, 092508 (2006); 10.1063/1.2355451 Adaptive optimal stochastic state feedback control of resistive wall modes in tokamaks Phys. Plasmas 13

  2. A Lower Bound on the Feedback Capacity of Finite-State ISI Channels Shaohua Yang, Aleksandar Kavcic

    E-Print Network [OSTI]

    Kavcic, Aleksandar

    A Lower Bound on the Feedback Capacity of Finite-State ISI Channels Shaohua Yang, Aleksandar Kavci on the feedback capacity of finite-state inter-symbol interference (ISI) channels. The transition probabilities as reported in [4]. Finite-state ISI channels are channels with memory. For channels with memory, feedback can

  3. ISIT 2003, Yokohama, Japan, June 29 July 4, 2003 Delayed Feedback Capacity of Finite-State Machine Channels

    E-Print Network [OSTI]

    Kavcic, Aleksandar

    of a finite-state machine channel is Cfb = sup P I(X Y ), (2) where the supremum is over the Markov source, the delayed feedback capacity Cfb equals to the non-delayed feedback capacity ~Cfb of the channel ( ~Xt, ~St programming algo- rithms [1]. Let C be the channel capacity without feedback, then C = lim Cfb and C

  4. PUBLISHED ONLINE: 26 JANUARY 2015 | DOI: 10.1038/NGEO2346 The remote impacts of climate feedbacks on

    E-Print Network [OSTI]

    Frierson, Dargan

    transport (atmospheric and oceanic). In physical terms, a positive-feedback region is less efficient feedbacks aggregate into a regional and global climate response. Here we present a simple, moist energy GCMs. For the zonal-mean net feedback (measured in W m-2 K-1 , see equation (1)), the spread among 12

  5. Mechanical Buckling: Mechanics, Metrology, and Stretchable Electronics

    E-Print Network [OSTI]

    Rogers, John A.

    Mechanical Buckling: Mechanics, Metrology, and Stretchable Electronics By Dahl-Young Khang, John A of wrinkling is in aging human skin. All such phenomena originate from the same mechanism, i.e., mechanical of the wave, or their wavelength, depends upon the film thickness and/or mechanical properties of materials

  6. Power management for wireless adapters using multiple feedback metrics

    E-Print Network [OSTI]

    % less energy consumption. In [23], a transport layer mechanism enables the interface periodically consumption has been proposed in [25], which improved energy efficiency by 32% in best case scenario. This mechanism measures the quality of the transmission and adjusts the transmission power accordingly

  7. Feedback control of inertial microfluidics using axial control forces

    E-Print Network [OSTI]

    Christopher Prohm; Holger Stark

    2014-02-03

    Inertial microfluidics is a promising tool for many lab-on-a-chip applications. Particles in channel flows with Reynolds numbers above one undergo cross-streamline migration to a discrete set of equilibrium positions in square and rectangular channel cross sections. This effect has been used extensively for particle sorting and the analysis of particle properties. Using the lattice Boltzmann method, we determine equilibrium positions in square and rectangular cross sections and classify their types of stability for different Reynolds numbers, particle sizes, and channel aspect ratios. Our findings thereby help to design microfluidic channels for particle sorting. Furthermore, we demonstrate how an axial control force, which slows down the particles, shifts the stable equilibrium position towards the channel center. Ultimately, the particles then stay on the centerline for forces exceeding a threshold value. This effect is sensitive to particle size and channel Reynolds number and therefore suggests an efficient method for particle separation. In combination with a hysteretic feedback scheme, we can even increase particle throughput.

  8. Analyzing Vehicle Fuel Saving Opportunities through Intelligent Driver Feedback

    SciTech Connect (OSTI)

    Gonder, J.; Earleywine, M.; Sparks, W.

    2012-06-01

    Driving style changes, e.g., improving driver efficiency and motivating driver behavior changes, could deliver significant petroleum savings. This project examines eliminating stop-and-go driving and unnecessary idling, and also adjusting acceleration rates and cruising speeds to ideal levels to quantify fuel savings. Such extreme adjustments can result in dramatic fuel savings of over 30%, but would in reality only be achievable through automated control of vehicles and traffic flow. In real-world driving, efficient driving behaviors could reduce fuel use by 20% on aggressively driven cycles and by 5-10% on more moderately driven trips. A literature survey was conducted of driver behavior influences, and pertinent factors from on-road experiments with different driving styles were observed. This effort highlighted important driver influences such as surrounding vehicle behavior, anxiety over trying to get somewhere quickly, and the power/torque available from the vehicle. Existing feedback approaches often deliver efficiency information and instruction. Three recommendations for maximizing fuel savings from potential drive cycle improvement are: (1) leveraging applications with enhanced incentives, (2) using an approach that is easy and widely deployable to motivate drivers, and (3) utilizing connected vehicle and automation technologies to achieve large and widespread efficiency improvements.

  9. Simulations of Pregalactic Structure Formation with Radiative Feedback

    E-Print Network [OSTI]

    Marie E. Machacek; Greg L. Bryan; Tom Abel

    2000-07-14

    We present results from three-dimensional hydrodynamic simulations of the high redshift collapse of pregalactic clouds including feedback effects from a soft H2 photodissociating UV radiation field. The simulations use an Eulerian adaptive mesh refinement technique to follow the nonequilibrium chemistry of nine chemical species with cosmological initial conditions drawn from a popular Lambda-dominated cold dark matter model. The results confirm that the soft UV background can delay the cooling and collapse of small halos (~10^6 Msun). For reasonable values of the photo-dissociating flux, the H2 fraction is in equilibrium throughout most of the objects we simulate. We determine the mass threshold for collapse for a range of soft-UV fluxes and also derive a simple analytic expression. Continuing the simulations beyond the point of initial collapse demonstrates that the fraction of gas which can cool depends mostly on the virial mass of the halo and the amount of soft-UV flux, with remarkably little scatter. We parameterize this relation, for use in semi-analytic models.

  10. The unstable CO2 feedback cycle on ocean planets

    E-Print Network [OSTI]

    Kitzmann, D; Godolt, M; Grenfell, J L; Heng, K; Patzer, A B C; Rauer, H; Stracke, B; von Paris, P

    2015-01-01

    Ocean planets are volatile rich planets, not present in our Solar System, which are thought to be dominated by deep, global oceans. This results in the formation of high-pressure water ice, separating the planetary crust from the liquid ocean and, thus, also from the atmosphere. Therefore, instead of a carbonate-silicate cycle like on the Earth, the atmospheric carbon dioxide concentration is governed by the capability of the ocean to dissolve carbon dioxide (CO2). In our study, we focus on the CO2 cycle between the atmosphere and the ocean which determines the atmospheric CO2 content. The atmospheric amount of CO2 is a fundamental quantity for assessing the potential habitability of the planet's surface because of its strong greenhouse effect, which determines the planetary surface temperature to a large degree. In contrast to the stabilising carbonate-silicate cycle regulating the long-term CO2 inventory of the Earth atmosphere, we find that the CO2 cycle feedback on ocean planets is negative and has strong...

  11. MECHANICAL ENGINEERING Curriculum Notes

    E-Print Network [OSTI]

    Mohan, Chilukuri K.

    MECHANICAL ENGINEERING Curriculum Notes 2013-2014 1. Mechanical engineering students must complete of technical electives. 2. Technical electives must be taken within the Mechanical and Aerospace Engineering

  12. Physicalism versus quantum mechanics

    E-Print Network [OSTI]

    Stapp, Henry P; Theoretical Physics Group; Physics Division

    2009-01-01

    Foundations of Quantum Mechanics. (Princeton UniversityMind, Matter, and Quantum Mechanics, (Springer, Berlin & NewMindful Universe: Quantum Mechanics and the Participating

  13. Sandia Energy - Mechanical Testing

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mechanical Testing Home Stationary Power Nuclear Fuel Cycle Advanced Nuclear Energy Nuclear Energy Systems Laboratory (NESL) Brayton Lab Mechanical Testing Mechanical...

  14. American Economic Journal: Macroeconomics (2010): 158194 http://www.aeaweb.org/articles.php?doi=10.1257/mac.2.4.158

    E-Print Network [OSTI]

    2010-01-01

    . In these models, tariffs raise per capita gross domestic product (GDP) when they target the industry subject structure is posi- tively correlated with long-term per capita GDP growth. Testing for causal mechanisms, we for each new variety, and the cost of

  15. Vehicle Technologies Office Merit Review 2014: Look-Ahead Driver Feedback and Powertrain Management

    Broader source: Energy.gov [DOE]

    Presentation given by Eaton at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about look-ahead driver feedback and...

  16. Passive intrinsic-linewidth narrowing of ultraviolet extended-cavity diode laser by weak optical feedback

    E-Print Network [OSTI]

    Samutpraphoot, Polnop

    We present a simple method for narrowing the intrinsic Lorentzian linewidth of a commercial ultraviolet grating extended-cavity diode laser (TOPTICA DL Pro) using weak optical feedback from a long external cavity. We achieve ...

  17. GALACTIC ANGULAR MOMENTUM IN THE ILLUSTRIS SIMULATION: FEEDBACK AND THE HUBBLE SEQUENCE

    E-Print Network [OSTI]

    Genel, Shy

    We study the stellar angular momentum of thousands of galaxies in the Illustris cosmological simulation, which captures gravitational and gas dynamics within galaxies, as well as feedback from stars and black holes. We ...

  18. You must be creative! The effect of performance feedback on intrinsic motivation and creativity 

    E-Print Network [OSTI]

    Benzer, Justin Kane

    2009-05-15

    that interest is not a valid proxy for intrinsic motivation in within-subjects designs. Future studies should test the proposition that feedback affects intrinsic motivation, which in turn affects creative performance, and creative performance affects interest....

  19. A Positive Feedback Synapse from Retinal Horizontal Cells to Cone Photoreceptors

    E-Print Network [OSTI]

    Alford, Simon

    an inhibitory synapse. Here we report that HCs also transmit to cone terminals a positive feedback signal cell; IPL, inner plexiform layer; mEPSC, miniature excitatory postsynaptic current; NO, nitric oxide

  20. Conversational Modifications and Feedback in NS-NS and NS-NNS Children's Interactions 

    E-Print Network [OSTI]

    Dolan Geraghty, Kathleen

    This study investigates task and interlocutor effects on feedback in children's interaction. Children were assigned to NS-NS (n=6 pairs) and NS-NNS (n=7 pairs) pairs and engaged in two tasks with their partner: (a) an ...

  1. Feedback" An Article for Smart Grid News The Smart Grid Transition...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sharing Smart Grid Experiences through Performance Feedback" An Article for Smart Grid News The Smart Grid Transition-Getting Started We are on the ground floor of a Smart Grid...

  2. Network coding, multi-packet reception, and feedback : design tools for wireless broadcast networks

    E-Print Network [OSTI]

    Rezaee, Arman

    2011-01-01

    In this thesis, we address the combination of three technologies in wireless broadcast networks: network coding, multi-packet reception (MPR) and feedback. We will primarily discuss the performance of a single-hop network, ...

  3. A Feedback-based Adaptive Broadcast Coding Scheme for Reducing In-order Delivery Delay

    E-Print Network [OSTI]

    Medard, Muriel

    We propose a new feedback-based adaptive coding scheme for a packet erasure broadcast channel. The main performance metric of interest is the delay. We consider two types of delay - decoding delay and delivery delay. ...

  4. Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine

    E-Print Network [OSTI]

    Silva, Filipe Faria Da

    Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip VSWT

  5. Performing temperature feedback controlled tissue photo-coagulation using magnetic resonance thermometry 

    E-Print Network [OSTI]

    Sampath, Smita

    1999-01-01

    controlled photo-coagulation using magnetic resonance imaging as the non-invasive means of temperature feedback. The desired coagulation depth was controlled at a constant temperature of 40 degrees for different amounts of time and the actual coagulation...

  6. ENOC 2008, Saint Petersburg, Russia, June, 30July, 4 2008 TIME-DELAYED FEEDBACK CONTROL

    E-Print Network [OSTI]

    Fiedler, Bernold

    ENOC 2008, Saint Petersburg, Russia, June, 30­July, 4 2008 TIME-DELAYED FEEDBACK CONTROL and Socolar, 2001; Pyra- gas, Pyragas and Benner, 2004; Pyragas and Pyragas, 2006]. We have refuted

  7. Development of an isolated flyback converter employing boundary-mode operation and magnetic flux sensing feedback

    E-Print Network [OSTI]

    Kenia, Mayur V. (Mayur Vasant), 1981-

    2004-01-01

    This thesis focuses on the marriage of magnetic-flux-sensing feedback and boundary-mode operation in a flyback converter to create a simple, small, low-cost, isolated, and tightly regulated power supply. Although each ...

  8. Evaluation of Force Feedback Requirements for Minimally Invasive Lung Tumour Localization

    E-Print Network [OSTI]

    Naish, Michael D.

    Evaluation of Force Feedback Requirements for Minimally Invasive Lung Tumour Localization Greig L describes experiments that were conducted on ex-vivo porcine lung, using artificial tumours, to elucidate

  9. Participant/assessor personality characteristics that influence feedback acceptance in developmental assessment centers 

    E-Print Network [OSTI]

    Bell, Suzanne Tamara

    2001-01-01

    The objective of the present study was to determine whether specified factors influenced the acceptance of feedback by participants (N = 113) in an operational developmental assessment center. Specifically, the relationship between participants...

  10. Final Report on the Fuel Saving Effectiveness of Various Driver Feedback Approaches

    SciTech Connect (OSTI)

    Gonder, J.; Earleywine, M.; Sparks, W.

    2011-03-01

    This final report quantifies the fuel-savings opportunities from specific driving behavior changes, identifies factors that influence drivers' receptiveness to adopting fuel-saving behaviors, and assesses various driver feedback approaches.

  11. Approximation Algorithms for the Feedback Vertex Set Problem with Applications to

    E-Print Network [OSTI]

    Roth, Ronny

    , so called blackout vertices, is not allowed to participate in any feedback vertex set. It is shown. An application in the area of Bayesian inference of graphs with blackout vertices is also presented

  12. Permafrost degradation and methane: low risk of biogeochemical climate-warming feedback

    E-Print Network [OSTI]

    Gao, Xiang

    Climate change and permafrost thaw have been suggested to increase high latitude methane emissions that could potentially represent a strong feedback to the climate system. Using an integrated earth-system model framework, ...

  13. An investigation of the performance feedback process using a self-appraisal 

    E-Print Network [OSTI]

    DeGregorio, Marybeth

    1985-01-01

    Problems with Supervisory Feedback. Self-Appraisal and Performance Feedback 16 Disadvantages of the self-appraisal 17 The Interactive Approach. The interactive advantage. 19 20 HYPOTHESES. 22 METHOD. 25 Subjects. Performance Task Design... helpful constructive atmosphere along with high levels of employee participation and mutual goal-setting affected satisfaction with the interview, motivation to improve performance and actual performance improvements. A more detailed investigation...

  14. Modification of {Delta}{sup Prime} by magnetic feedback and kinetic effects

    SciTech Connect (OSTI)

    Liu Yueqiang; Hastie, R. J.; Hender, T. C. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2012-09-15

    Two possible ways of modifying the linear tearing mode index, by active magnetic feedback and by drift kinetic effects of deeply trapped particles, are analytically investigated. Magnetic feedback schemes, studied in this work, are found generally stabilizing for {Delta}{sup Prime }. The drift kinetic effects from both thermal particles and hot ions tend to reduce the power of the large solution from the outer region. This generally leads to a destabilization of {Delta} Prime for the toroidal analytic equilibria considered here.

  15. Poisoned Feedback: The Impact of Malicious Users in Closed-Loop Multiuser MIMO Systems

    E-Print Network [OSTI]

    Mukherjee, Amitav

    2010-01-01

    Accurate channel state information (CSI) at the transmitter is critical for maximizing spectral efficiency on the downlink of multi-antenna networks. In this work we analyze a novel form of physical layer attacks on such closed-loop wireless networks. Specifically, this paper considers the impact of deliberately inaccurate feedback by malicious users in a multiuser multicast system. Numerical results demonstrate the significant degradation in performance of closed-loop transmission schemes due to intentional feedback of false CSI by adversarial users.

  16. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Ductile failure in structural materials has been a problem the Temple Foundation Professorship in the Department of Aerospace Engineering and Engineering Mechanics, multiscale experimental mechanics, mechanics of polymers. He is a fellow of the American Society

  17. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Three Dimensional Traction Force Microscopy with Applications in Cell Mechanics abstract The interactions between biochemical and mechanical signals during-dimensional measurement techniques are needed to investigate the effect of mechanical properties of the substrate

  18. Research Review Mechanical Engineering

    E-Print Network [OSTI]

    Theune, Mariët

    Research Review Mechanical Engineering University of Twente #12;QANU / Research Review Mechanical;QANU / Research Review Mechanical Engineering / University of Twente 3 Report on the research assessment of Mechanical Engineering at the University of Twente Contents Preface

  19. Terrestrial biogeochemical feedbacks in the climate system: from past to future

    SciTech Connect (OSTI)

    Arneth, A.; Harrison, S. P.; Zaehle, S.; Tsigaridis, K; Menon, S; Bartlein, P.J.; Feichter, J; Korhola, A; Kulmala, M; O'Donnell, D; Schurgers, G; Sorvari, S; Vesala, T

    2010-01-05

    The terrestrial biosphere plays a major role in the regulation of atmospheric composition, and hence climate, through multiple interlinked biogeochemical cycles (BGC). Ice-core and other palaeoenvironmental records show a fast response of vegetation cover and exchanges with the atmosphere to past climate change, although the phasing of these responses reflects spatial patterning and complex interactions between individual biospheric feedbacks. Modern observations show a similar responsiveness of terrestrial biogeochemical cycles to anthropogenically-forced climate changes and air pollution, with equally complex feedbacks. For future conditions, although carbon cycle-climate interactions have been a major focus, other BGC feedbacks could be as important in modulating climate changes. The additional radiative forcing from terrestrial BGC feedbacks other than those conventionally attributed to the carbon cycle is in the range of 0.6 to 1.6 Wm{sup -2}; all taken together we estimate a possible maximum of around 3 Wm{sup -2} towards the end of the 21st century. There are large uncertainties associated with these estimates but, given that the majority of BGC feedbacks result in a positive forcing because of the fundamental link between metabolic stimulation and increasing temperature, improved quantification of these feedbacks and their incorporation in earth system models is necessary in order to develop coherent plans to manage ecosystems for climate mitigation.

  20. Coupling biochemistry and mechanics in cell adhesion: a model for inhomogeneous stress fiber contraction

    E-Print Network [OSTI]

    A. Besser; U. S. Schwarz

    2007-10-24

    Biochemistry and mechanics are closely coupled in cell adhesion. At sites of cell-matrix adhesion, mechanical force triggers signaling through the Rho-pathway, which leads to structural reinforcement and increased contractility in the actin cytoskeleton. The resulting force acts back to the sites of adhesion, resulting in a positive feedback loop for mature adhesion. Here we model this biochemical-mechanical feedback loop for the special case when the actin cytoskeleton is organized in stress fibers, which are contractile bundles of actin filaments. Activation of myosin II molecular motors through the Rho-pathway is described by a system of reaction-diffusion equations, which are coupled into a viscoelastic model for a contractile actin bundle. We find strong spatial gradients in the activation of contractility and in the corresponding deformation pattern of the stress fiber, in good agreement with experimental findings.

  1. Galaxy Formation: CDM, Feedback and the Hubble Sequence

    E-Print Network [OSTI]

    Jesper Sommer-Larsen; Martin Gotz; Laura Portinari

    2003-10-15

    TreeSPH simulations of galaxy formation in a LCDM cosmology, with star formation, energetic stellar feedback and a meta-galactic UV field have been performed, resulting in realistic disk, S0 and E galaxies at z=0. The disk galaxies are deficient in angular momentum by only about a factor of two compared to observations for runs where fairly strong star-bursts in early, proto-galactic clouds lead to "blow-away" of the remaining gas. The surface density profiles of the stellar disks are approximately exponential and those of the bulges range from exponential to r^(1/4). B/D ratios and integrated B-V colours are consistent with observations. The observed I-band TF relation can be matched with M/L_I ~ 0.8, in fair agreement with recent determinations. The (E/S0)s have approximately r^(1/4) profiles, non disk-like kinematics and are flattened due to non-isotropic stellar velocity distributions. We predict hot halo gas to cool out and accrete onto the Galactic disk at 0.5-1 Msun/yr at z=0, consistent with upper limits from FUSE observations of O VI. We analyzed two Milky Way-sized galaxies and find accretion rates, and X-ray halo luminosities, 6-7 times larger at z=1 than at z=0. The gas infall declines nearly exponentially with time, supporting the approximation often used in chemical evolution models. The infall time-scales are comparable to what is used to solve the "G-dwarf problem". One disk forms "inside-out", the other "outside-in". For both, the mean stellar ages in the outskirts agree with findings for the disk of M31. The amount of hot gas in disk galaxy haloes is consistent with observational upper limits, as are dispersion measures to pulsars in the globular cluster M53 and the LMC, which were "inserted" in the disk galaxy haloes.

  2. Commissioning of FPGA-based Transverse and Longitudinal Bunch-by-Bunch Feedback System for the TLS

    SciTech Connect (OSTI)

    Hu, K. H.; Kuo, C. H.; Lau, W. K.; Yeh, M. S.; Hsu, S. Y.; Chou, P. J.; Wang, M. H.; Lee, Demi; Chen, Jenny; Wang, C. J.; Hsu, K. T. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Kobayashi, K.; Nakamura, T. [JASRI/SPring-8, Hyogo (Japan); Dehler, M. [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2006-11-20

    Multi-bunch instabilities deteriorate beam quality, increasing beam emittance, or even causing beam loss in the synchrotron light source. The feedback system is essential to suppress multi-bunch instabilities caused by the impedances of beam ducts, and trapped ions. A new FPGA based transverse and longitudinal bunch-by-bunch feedback system have been commissioned at the Taiwan Light Source recently, A single feedback loop is used to simultaneously suppress the horizontal and the vertical multi-bunch instabilities. Longitudinal instabilities caused by cavity-like structures are suppressed by the longitudinal feedback loop. The same FPGA processor is employed in the transverse feedback and the longitudinal feedback system respectively. Diagnostic memory is included in the system to capture the bunch oscillation signal, which supports various studies.

  3. Mechanical & Biomedical Engineering

    E-Print Network [OSTI]

    Barrash, Warren

    Mechanical & Biomedical Engineering Department BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING COURSE 105 Mechanical Engineering Graphics 3 CHEM 111L College Chemistry Lab (DLN) 1 ENGL 102 English PHYS 211 Mechanics, Waves & Heat (DLN) 4 UF 100 Intellectual Foundations 3 PHYS 211L Mechanics, Waves

  4. Mechanical Engineering & Thermal Group

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    LASP's mechanical analysts also lead mechanical verification testing including: random vibration, forceMechanical Engineering & Thermal Group The Mechanical Engineering (ME) & Thermal Group at LASP has, and ground- based mechanical systems. Instrument Design Building on decades of design experience that has

  5. Feedback control of oscillations in combustion and cavity flows

    E-Print Network [OSTI]

    Illingworth, Simon J

    2010-02-09

    .3.2 Adaptation rates . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.4 Modal adaptive controller . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.5 Description of the thermoacoustic network model . . . . . . . . . . . . . 35 3.6 Adaptive control... combustion is an efficient acoustic source (Dowling & Ffowcs Williams, 1983) and combustors tend to be highly resonant systems, which together can lead to self-excited oscillations by the following mechanism. Pressure waves, generated by unsteady heat release...

  6. Feedback Regulated Turbulence, Magnetic Fields, and Star Formation Rates in Galactic Disks

    E-Print Network [OSTI]

    Kim, Chang-Goo

    2015-01-01

    We use three-dimensional magnetohydrodynamic (MHD) simulations to investigate the quasi-equilibrium states of galactic disks regulated by star formation feedback. We incorporate effects from massive-star feedback via time-varying heating rates and supernova (SN) explosions. We find that the disks in our simulations rapidly approach a quasi-steady state that satisfies vertical dynamical equilibrium. The star formation rate (SFR) surface density self-adjusts to provide the total momentum flux (pressure) in the vertical direction that matches the weight of the gas. We quantify feedback efficiency by measuring feedback yields, \\eta_c\\equiv P_c/\\Sigma_SFR (in suitable units), for each pressure component. The turbulent and thermal feedback yields are the same for HD and MHD simulations, \\eta_th~1 and \\eta_ turb~4, consistent with the theoretical expectations. In MHD simulations, turbulent magnetic fields are rapidly generated by turbulence, and saturate at a level corresponding to \\eta_mag,t~1. The presence of magn...

  7. COMMISSIONING OF THE DIGITAL TRANSVERSE BUNCH-BY-BUNCH FEEDBACK SYSTEM FOR THE TLS.

    SciTech Connect (OSTI)

    HU, K.H.; KUO, C.H.; CHOU, P.J.; LEE, D.; HSU, S.Y.; CHEN, J.; WANG, C.J.; HSU, K.T.; KOBAYASHI, K.; NAKAMURA, T.; CHAO, A.W.; WENG, W.T.

    2006-06-26

    Multi-bunch instabilities degrade beam quality through increased beam emittance, energy spread and even beam loss. Feedback systems are used to suppress multi-bunch instabilities associated with the resistive wall of the beam ducts, cavity-like structures, and trapped ions. A new digital transverse bunch-by-bunch feedback system has recently been commissioned at the Taiwan Light Source, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance and improves damping for transverse instability at high currents, such that top-up operation is achieved. After a coupled-bunch transverse instability was suppressed, more than 350 mA was successfully stored during preliminary commissioning. In this new system, a single feedback loop simultaneously suppresses both horizontal and vertical multi-bunch instabilities. Investigating the characteristics of the feedback loop and further improving the system performances are the next short-term goals. The feedback system employs the latest generation of field-programmable gate array (FPGA) processor to process bunch signals. Memory has been installed to capture up to 250 msec of bunch oscillation signal, considering system diagnostics suitable to support various beam physics studies.

  8. Enhancement of mobility in an interacting colloidal system under feedback control

    E-Print Network [OSTI]

    Robert Gernert; Sabine H. L. Klapp

    2015-06-05

    Feedback control schemes are a promising way to manipulate transport properties of driven colloidal suspensions. In the present article we suggest a feedback scheme to enhance the collective transport of colloidal particles with repulsive interactions through a one-dimensional tilted washboard potential. The control is modelled by a harmonic confining potential, mimicking an optical "trap", with the center of this trap moving with the (instantaneous) mean particle position. Our theoretical analysis is based on the Smoluchowski equation combined with Dynamical Density Functional Theory (DDFT) for systems with hard-core or ultra-soft (Gaussian) interactions. For either type of interaction we find that the feedback control can lead to an enhancement of the mobility by several orders of magnitude relative to the uncontrolled case. The largest effects occur for intermediate stiffness of the trap and large particle numbers. Moreover, in some regions of the parameter space the feedback control induces oscillations of the mean velocity. Finally, we show that the enhancement of mobility is robust against a small time delay in implementing the feedback control.

  9. Carbon-nitrogen interactions regulate climate-carbon cycle feedbacks: results from an atmosphere-ocean general circulation model

    E-Print Network [OSTI]

    2009-01-01

    2009 P. E. Thornton et al. : Carbon-nitrogen interactionsregulate climate-carbon cycle feedbacks Monfray, P. ,T. H. : A global ocean carbon climatology: Results from

  10. Mechanical, Industrial & Manufacturing

    E-Print Network [OSTI]

    Balasubramanian, Ravi

    Mechanical, Industrial & Manufacturing Engineering (MIME) COLLEGE OF ENGINEERING FY2013 Oregon graduate degrees (MS, MEng, PhD) in mechanical engineering, industrial engineering, and materials science. We offer bachelor's degrees in mechanical, industrial, manufacturing, and energy systems engineering

  11. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Despite an enormous range of applications and centuries. Nicholas Ouellette is an Associate Professor in the Department of Mechanical Engineering & Materials Structures in Turbulent Flow Nicholas Ouellette Department of Mechanical Engineering & Material Sciences Yale

  12. Mechanical Systems Signal Processing

    E-Print Network [OSTI]

    Verleysen, Michel

    Mechanical Systems and Signal Processing Mechanical Systems and Signal Processing 22 (2008) 155 Department of Mechanical Engineering, University of Sheffield, Mappin Street S1 3JD Sheffield, UK Received 27

  13. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering This presentation presents the stability analysis of time- delay of the Department of Mechanical and Industrial Engineering, Southern Illinois University Edwardsville, where he has Gu Dept. of Mechanical & Industrial Engineering Southern Illinois University, Edwardsville March 27

  14. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering With the increases in computational power and numerical methods a series of research challenges. These challenges involve many branches of mechanical engineering: mechanics, dynamics, tribology, statistical modeling, experimentation, and numerical methods. During

  15. Mechanical & Industrial Engineering

    E-Print Network [OSTI]

    Mountziaris, T. J.

    Mechanical & Industrial Engineering 1 Welcome MIE Industrial Advisory Board October 15, 2010 #12;Mechanical & Industrial Engineering 2 MIE Dorothy Adams Undergraduate/Graduate Secretary David Schmidt Associate Professor & Graduate Program Director #12;Mechanical & Industrial Engineering 3 MIE James Rinderle

  16. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Today's design environments take advantage of powerful professor of Mechanical Engineering at Carnegie Mellon University. He is the founder of Visual Design award and American Society of Mechanical Engineers Design Automation Society Young Investigator Award

  17. Department of Mechanical & Aerospace

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    in mechanics, electrical theory, kinematics, thermodynamics, fluid mechanics, heat transfer and materials dynamics, fluid dynamics, propulsion and structures. While each program features a solid technicalDeveloping Leaders of Innovation Department of Mechanical & Aerospace Engineering #12;Emphasizing

  18. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The gap between `advanced' prosthetic technology was educated in Mechanical and Biomedical Engineering at the University of Illinois and Northwestern University

  19. Mechanical Performance Extreme Conditions

    E-Print Network [OSTI]

    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

  20. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering In the pursuit of developing manned, reusable hypersonic will experience thermal and mechanical loads. The research presented will discuss advancements in structural

  1. Thesis proposal CSF Brazil 2014 Semantic mechanisms for dynamic and evolving processes based on experience feedback and

    E-Print Network [OSTI]

    Bordenave, Charles

    based Product Lifecycle Management system (e-PLM) becomes a popular #12;option for managing product facilitate product information exchanging between heterogeneous PDM (Product Data Management) systems Management) and support collaborative development by integrating data produced at dispersed locations

  2. Global climate feedbacks: Conclusions and recommendations of the June 1990 BNL workshop

    SciTech Connect (OSTI)

    Manowitz, B.

    1990-08-01

    The issue of global change initiated by increases in the concentrations of CO{sub 2} and other greenhouse gases is a scientific issue with major policy implications. The best means to examine the response of the Earth's climate to prospective perturbations in radiative forcing caused by such changes, and to other industrial activities, is modeling, specifically by means of general circulation models (GCMs) of the Earth's atmosphere and of the coupled atmosphere-ocean system. The purpose of this workshop was to identify the feedbacks inherent in the Earth's climate that actually or potentially govern the system's response to perturbations, to identify gaps in knowledge that preclude the accurate representation of these feedbacks in models, and to identify research required to represent these feedbacks accurately in models.

  3. Observation of photo-thermal feed-back in a stable dual-carrier optical spring

    E-Print Network [OSTI]

    David Kelley; James Lough; Fabian Mangaña-Sandoval; Antonio Perreca; Stefan W. Ballmer

    2015-09-04

    We report on the observation of photo-thermal feed-back in a stable dual-carrier optical spring. The optical spring is realized in a 7 cm Fabry-Perot cavity comprised of a suspended 0.4 g small end mirror and a heavy input coupler, illuminated by two optical fields. The frequency, damping and stability of the optical spring resonance can be tuned by adjusting the power and detuning of the two optical fields, allowing for a precise measurement of the absorption-induced photo-thermal feedback. The magnitude and frequency dependence of the observed photo-thermal effect are consistent with predicted corrections due to transverse thermal diffusion and coating structure. While the observed photo-thermal feed-back tends to destabilize the optical spring, we also propose a small coating modification that would change the sign of the effect, making a single-carrier stable optical spring possible.

  4. High Precision Tune and Coupling Feedback and Beam Transfer Function Measurements in RHIC

    SciTech Connect (OSTI)

    Minty, M.; Curcio, A.; Dawson, C.; Degen, C.; Luo, Y.; Marr, G.; Martin, B.; Marusic, A.; Mernick, K.; Oddo, P.; Russo, T.; Schoefer, V.; Schroeder, R.; Schultheiss, C.; Wilinski, M.

    2010-05-23

    Precision measurement and control of the betatron tunes and betatron coupling in the Relativistic Heavy Ion Collider (RHIC) are required for establishing and maintaining both good operating conditions and, particularly during the ramp to high beam energies, high proton beam polarization. While the proof-of-principle for simultaneous tune and coupling feedback was successfully demonstrated earlier, routine application of these systems has only become possible recently. Following numerous modifications for improved measurement resolution and feedback control, the time required to establish full-energy beams with the betatron tunes and coupling regulated by feedback was reduced from several weeks to a few hours. A summary of these improvements, select measurements benefitting from the improved resolution and a review of system performance are the subject of this report.

  5. High precision tune and coupling measurements and tune/coupling feedback in RHIC

    SciTech Connect (OSTI)

    Minty, M.; Curcio, A.; Dawson, C.; Degen, C.; Luo, Y.; Marr, G.; Martin, B.; Marusic, A.; Mernick, K.; Oddo, P.; Russo, T.; Schoefer, V.; Schroeder, R.; Schulthiess, C.; Wilinski, M.

    2010-08-01

    Precision measurement and control of the betatron tunes and betatron coupling in RHIC are required for establishing and maintaining both good operating conditions and, particularly during the ramp to high beam energies, high proton beam polarization. While the proof-of-principle for simultaneous tune and coupling feedback was successfully demonstrated earlier, routine application of these systems has only become possible recently. Following numerous modifications for improved measurement resolution and feedback control, the time required to establish full-energy beams with the betatron tunes and coupling regulated by feedback was reduced from several weeks to a few hours. A summary of these improvements, select measurements benefitting from the improved resolution and a review of system performance are the subject of this report.

  6. Delayed feedback control of unstable steady states with high-frequency modulation of the delay

    E-Print Network [OSTI]

    Aleksandar Gjurchinovski; Thomas Jüngling; Viktor Urumov; Eckehard Schöll

    2013-08-21

    We analyze the stabilization of unstable steady states by delayed feedback control with a periodic time-varying delay in the regime of a high-frequency modulation of the delay. The average effect of the delayed feedback term in the control force is equivalent to a distributed delay in the interval of the modulation, and the obtained distribution depends on the type of the modulation. In our analysis we use a simple generic normal form of an unstable focus, and investigate the effects of phase-dependent coupling and the influence of the control loop latency on the controllability. In addition, we have explored the influence of the modulation of the delays in multiple delay feedback schemes consisting of two independent delay lines of Pyragas type. A main advantage of the variable delay is the considerably larger domain of stabilization in parameter space.

  7. High-Gradient Tests of the Single-Cell SC Cavity with a Feedback Waveguide

    SciTech Connect (OSTI)

    Yakovlev, V.; Solyak, N.; Wu, G.; Ge, M.; Gonin, I.; Khabiboulline, T.; Ozelis, J.; Rowe, A. [Fermilab, Batavia, IL 60510 (United States); Avrakhov, P.; Kanareykin, A. [Euclid TechLabs, LLC, Solon, Ohio 44139 (United States); Rathke, J. [AES, Medford, NY 11763 (United States)

    2010-11-04

    Use of a superconducting (SC) traveling-wave accelerating (STWA) structure with a small phase advance per cell, rather than a standing-wave structure, may provide a significant increase in the accelerating gradient in the ILC linac [1]. For the same surface electric and magnetic fields, the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing-wave cavities. In addition, the STWA allows longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed and manufactured to demonstrate the possibility of proper processing to achieve a high accelerating gradient. The first results of high-gradient tests of a prototype 1.3 GHz single-cell cavity with feedback waveguide will be presented.

  8. Time-delayed feedback control of delay-coupled neurosystems and lasers

    E-Print Network [OSTI]

    Philipp Hövel; Markus A. Dahlem; Thomas Dahms; Gerald Hiller; Eckehard Schöll

    2009-12-17

    We discuss applications of time-delayed feedback control to delay-coupled neural systems and lasers, in the framework of the FitzHugh-Nagumo neuron model and the Lang-Kobayashi laser model, respectively. In the context of neural systems, we will point out some complex scenarios of synchronized in-phase or antiphase oscillations, bursting patterns, or amplitude death, induced by delayed coupling in combination with delayed self-feedback in simple network motifs. For optical systems, we will show that multiple time-delayed feedback, realized by a Fabry-Perot resonator coupled to the laser, provides a valuable tool for the suppression of unwanted intensity pulsations, and leads to stable continuous-wave operation.

  9. An Evaluation of the Interactive Effects of Feedback Sequence and Timing on Efficacy and Preference

    E-Print Network [OSTI]

    Henley, Amy Jessica

    2014-05-31

    , run sessions, and brainstorm feedback statements. All of your encouragement and endless supply of samich jokes helped keep me motivated. This project would have been a PPC without you all! A big thank you goes out to Drs. Pam Neidert and Derek..., run sessions, and brainstorm feedback statements. All of your encouragement and endless supply of samich jokes helped keep me motivated. This project would have been a PPC without you all! A big thank you goes out to Drs. Pam Neidert and Derek...

  10. Hopf bifurcation analysis of the generalized Lorenz system with time delayed feedback control

    E-Print Network [OSTI]

    Rachele Barresi; Maria Carmela Lombardo; Marco Sammartino

    2015-01-02

    In this work we propose a feedback approach to regulate the chaotic behavior of the whole family of the generalized Lorenz system, by designing a nonlinear delayed feedback control. We first study the effect of the delay on the dynamics of the system and we investigate the existence of Hopf bifurcations. Then, by using the center manifold reduction technique and the normal form theory, we derive the explicit formulas for the direction, stability and period of the periodic solutions bifurcating from the steady state at certain critical values of the delay.

  11. Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Koven, C. D.; Chambers, J. Q.; Georgiou, K.; Knox, R.; Negron-Juarez, R.; Riley, W. J.; Arora, V. K.; Brovkin, V.; Friedlingstein, P.; Jones, C. D.

    2015-09-07

    To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore »situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr?1 increasing CO2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

  12. Controls on terrestrial carbon feedbacks by productivity vs. turnover in the CMIP5 Earth System Models

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Koven, C. D.; Chambers, J. Q.; Georgiou, K.; Knox, R.; Negron-Juarez, R.; Riley, W. J.; Arora, V. K.; Brovkin, V.; Friedlingstein, P.; Jones, C. D.

    2015-04-16

    To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into 4 categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), and apply the analysis separately to the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for 5 models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. Formore »dead carbon pools, the situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This responses arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times in response to increases in productivity. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully-coupled, biogeochemically-coupled, and radiatively-coupled 1% yr?1 increasing CO2 experiments. We disaggregate inter-model uncertainty in the globally-integrated equilibrium carbon responses to initial turnover times, inital productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may indicate a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the uncertainty in these processes.« less

  13. Mechanical Engineering Graduate Student

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    Mechanical Engineering Graduate Student Handbook January 2015 Department of Mechanical Engineering University of Wisconsin-Madison #12;1 Mechanical Engineering Web Page: http://www.engr.wisc.edu/me Graduate & Terrace Chairs) and Samantha Stepp (ME Building) #12;2 Department of Mechanical Engineering AGUIDE

  14. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Bone is a biological material with excellent material properties the properties at lower level serve as inputs for modeling at the next structural level. Mechanical properties and applied mechanics at Northwestern University. Prior to joining the faculty of mechanical engineering

  15. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Strategic Plan 2014-2018 College of Engineering, Architecture & Technology #12;Mechanical and Aerospace Engineering at Oklahoma State University was organized as Mechanical the strongest in the nation. MAE is proud to continue in this fine tradition, forging high quality mechanical

  16. Mechanical Engineering David Sumner

    E-Print Network [OSTI]

    Saskatchewan, University of

    Mechanical Engineering David Sumner david.sumner@usask.ca #12;Mechanical Engineering? · Design, production and use of mechanical systems that control and transform energy · Focused on engineering systems that involve heat, energy and motion · The broadest engineering discipline #12;Subject Areas · Fluid mechanics

  17. Mechanical & Industrial Engineering

    E-Print Network [OSTI]

    Mountziaris, T. J.

    Mechanical & Industrial Engineering 1 Welcome MIE Industrial Advisory Board May 5th, 2011 #12;Mechanical & Industrial Engineering 2 IAB 2010-2011 · David K. Anderson ­ Alden Research Laboratory, Inc went on for three weeks Mechanical & Industrial Engineering 6 #12;Reza Shahbazian Yassar Mechanical

  18. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The science of robotics is a unique combination of mechanical in Dayton, OH. Dr. Sodemann received a PhD in Mechanical Engineering from the Georgia Institute to recent advances in the science of robotics, and thus the machines perform primarily as mechanical devices

  19. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Nanocrystal superlattices are materials formed by assembly Professor in the Department of Mechanical Engineering and Applied Mechanics at the University her B.S. in Mechanical Engineering magna cum laude from Rice University in 1994 and was elected to Phi

  20. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering This talk concerns the effective behavior of heterogeneous media Science as well as the Executive Officer for Mechanical and Civil Engineering at the California Institute in Applied Mechanics from the American Society of Mechanical Engineers in 2004. He is currently an Editor

  1. INTRODUCTION TO THE MECHANICS

    E-Print Network [OSTI]

    Kaminski, Edouard

    INTRODUCTION TO THE MECHANICS OF A CONTINUOUS MEDIUM Lawrence E. Malvern Professor of Mechanics princi- ples common to all branches of solid and fluid mechanics, designed to appeal to the intuition science. The book arose from the need to provide a general preparation in contin- uum mechanics

  2. A 600 GHz InP HBT Amplifier Using Cross-Coupled Feedback Stabilization and Dual-Differential Power Combining

    E-Print Network [OSTI]

    Rodwell, Mark J. W.

    , amplifiers, cross-coupled feedback, power combining. I. INTRODUCTION Sub-millimeter-wave and lower terahertzA 600 GHz InP HBT Amplifier Using Cross-Coupled Feedback Stabilization and Dual-Differential Power , Mark Rodwell3 1 Teledyne Scientific Company, Thousand Oaks, CA, USA, 2 Jet Propulsion Laboratory

  3. IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 55, NO. 12, DECEMBER 2009 5353 Wiretap Channel With Secure Rate-Limited Feedback

    E-Print Network [OSTI]

    Franceschetti, Massimo

    as a secret key on top of Wyner's coding scheme for wiretap channels without feedback. Hence, when a feedback secret from Eve. If Eve has complete access to what Bob receives, Shannon showed that in order to achieve perfect secrecy, a secret key of entropy has to be shared between Alice and Bob. This fundamental yet

  4. Feedback Performance Control in Software Services Tarek F. Abdelzaher, John A. Stankovic, Chenyang Lu, Ronghua Zhang, and Ying Lu

    E-Print Network [OSTI]

    Stankovic, John A.

    of the feedback control design and implementation for software systems. Middleware solutions such as Control these performance guarantees are not effective for a large class of software systems. Recently, control theory has as those of feedback control. We describe modeling the software system and provide an example

  5. Role of ocean biology-induced climate feedback in the modulation of El Nin~o-Southern Oscillation

    E-Print Network [OSTI]

    Chen, .Dake

    penetration of solar radiation in the upper ocean, present- ing a feedback from ocean biology to physics represented by the penetration depth of solar radiation in the upper ocean (Hp), a field thus servingRole of ocean biology-induced climate feedback in the modulation of El Nin~o-Southern Oscillation

  6. Least Squares Pole Assignment by Memory-less Output Feedback* Dan-chi Jiang & J. B. Moore

    E-Print Network [OSTI]

    Moore, John Barratt

    Least Squares Pole Assignment by Memory-less Output Feedback* Dan-chi Jiang & J. B. Moore In this paper, a pole assignmentproblem of lineartime invariantcontrol system by memory- less output feedback is posed as a least squares poles assignmentproblem and analysed. The coat functions are appropriately

  7. Micromachined force-balance feedback accelerometer with optical displacement detection

    DOE Patents [OSTI]

    Nielson, Gregory N.; Langlois, Eric; Baker, Michael; Okandan, Murat; Anderson, Robert

    2014-07-22

    An accelerometer includes a proof mass and a frame that are formed in a handle layer of a silicon-on-an-insulator (SOI). The proof mass is separated from the frame by a back-side trench that defines a boundary of the proof mass. The accelerometer also includes a reflector coupled to a top surface of the proof mass. An optical detector is located above the reflector at the device side. The accelerometer further includes at least one suspension spring. The suspension spring has a handle anchor that extends downwards from the device side to the handle layer to mechanically support upward and downward movement of the proof mass relative to a top surface of the proof mass.

  8. MechanicalEngineering The Department of Mechanical

    E-Print Network [OSTI]

    for the informed development and optimization of materials. This talk will present our recent work on exploring, Ph.D. Associate Professor Department of Mechanical Engineering Department of Materials Science to thermo-mechanical loads is a fundamental requirement in the characterization of materials and structures

  9. A Large Ozone-Circulation Feedback & Its Implications for Global Warming Assessments

    E-Print Network [OSTI]

    Jackson, Sophie

    Peer A Large Ozone-Circulation Feedback & Its Implications for Global Warming Assessments PeerCO2, b T by 4xCO2, c T by O3 and d water vapour by O3. 4. GLOBAL WARMING RESPONSE 0 50 100 150 200 250) Figure 1 | Temporal evolution of the annual and global mean surface tem- perature anomalies. Interactive

  10. One Size Does Not Fit All: Applying the Transtheoretical Model to Energy Feedback Technology Design

    E-Print Network [OSTI]

    Greenberg, Saul

    . One remedy to this problem, and the focus of this paper, is to motivate sustainable energy usage feedback of energy usage. However, there is one problem - most tech- nologies use a "one, one approach to motivating sus- tainable energy usage behaviors is the development of tech- nologies

  11. Nonlinear dynamics of feedback modulated magnetic islands in toroidal plasmas Richard Fitzpatrick and Franois L. Waelbroeck

    E-Print Network [OSTI]

    Fitzpatrick, Richard

    because both heat and particles are able to travel radially from one side of an island chain to the otherNonlinear dynamics of feedback modulated magnetic islands in toroidal plasmas Richard Fitzpatrick-induced magnetic responses during nonlinear dynamics of magnetic islands due to resonant magnetic perturbations

  12. Feeling What You Hear: Tactile Feedback for Navigation of Audio Graphs

    E-Print Network [OSTI]

    Brewster, Stephen

    , UK e-mail: steven, stephen @dcs.gla.ac.uk Tel.: +44 (0)141 330 4966 ABSTRACT Access to digitally feedback to aid navigation. The results of a qualitative evaluation with a prototype interface are also Classification Keywords H.5.2 User Interfaces: Haptic I/O, User-centered design. INTRODUCTION In this information

  13. How strong is carbon cycle-climate feedback under global warming?

    E-Print Network [OSTI]

    Maryland at College Park, University of

    How strong is carbon cycle-climate feedback under global warming? Haifeng Qian Advisor: Prof. Ning IPCC report, global warming was predicted under different CO2 scenarios. Under such warming conditions carbon cycle to the climate system, which means that under the global warming condition, the ecosystem

  14. Limitations, performance and instrumentation of closed-loop feedback based distributed adaptive

    E-Print Network [OSTI]

    Beigl, Michael

    Limitations, performance and instrumentation of closed-loop feedback based distributed adaptive performance. Finally, we present measure- ments from an instrumentation using USRP software radios at various. This is especially useful in large scale sensor networks since the number of potentially available nodes

  15. Two-Hop Relay Channels with Limited FeedBack TELECOM ParisTech

    E-Print Network [OSTI]

    Boyer, Edmond

    Two-Hop Relay Channels with Limited FeedBack Ali Osmane TELECOM ParisTech Paris, France Email and feeds it back to the relays. We propose an iterative algorithm to find this optimal rotation vector by the destination and feed it back to the relays. This algorithm is shown to have the same performance as an optimal

  16. Haptic Feedback and Human Performance in a Dynamic Task Felix Huang R. Brent Gillespie Art Kuo

    E-Print Network [OSTI]

    Gillespie, Brent

    by human subjects executing a dynamic task. We present the results of experiments involving the control1 Haptic Feedback and Human Performance in a Dynamic Task Felix Huang R. Brent Gillespie Art Kuo of a ball and beam. Human subjects perform position targeting of the ball through hand operation of the beam

  17. Feedback suppression of rotating external kink instabilities in the presence of noise

    E-Print Network [OSTI]

    Mauel, Michael E.

    =vA/a, but a conducting wall at the plasma boundary can interact with the mode. The resulting plasma-wall mode is termed experimental demonstration of active feedback suppression of rotating external kink modes near the ideal wall limit in a tokamak using Kalman filtering to discriminate the n=1 kink mode from background noise

  18. Linear Gaussian Channels: Feedback Capacity under Power Constraints Shaohua Yang1

    E-Print Network [OSTI]

    Tatikonda, Sekhar

    information rate, is Cfb(n) = max P h(Y n 1 )/n - log 2e , (4) where the maximization is under the average and by the National Storage Industry Consortium. Theorem 1: The feedback capacity Cfb(n) is achieved by a Gauss

  19. Feedback control of an azimuthal oscillation in the E 3 B discharge of Hall thrusters

    E-Print Network [OSTI]

    azimuthal variation in density, electron temperature, and potential that rotates at about 10% of the local E, although it causes a rotating azimuthal variation in the current density to the anode, it does not show up to decrease in proportion to the current through that segment. The feedback resulted in the disappearance

  20. Feedback oscillations of stimulated brillouin scattering in plasmas with supersonic flow

    SciTech Connect (OSTI)

    Baumgaertel, K.; Sauer, K.

    1982-11-01

    Long-time stimulated Brillouin scattering oscillations may occur in subcritical plasmas with supersonic flow against the incident wave owing to a feedback of the scattered radiation. They are studied in the frame of both the parametric approximation and the mode-coupling theory.

  1. On Feedback Passivity of Discrete-Time Nonlinear Networked Control Systems with Packet Drops

    E-Print Network [OSTI]

    Antsaklis, Panos

    . At these time steps, the increase in storage function is not necessarily bounded by the supplied energy increase in storage function may be greater than the supplied energy at some time steps due to packet drops in closed-loop. Because the process is feedback passive, the resulting increase in storage function

  2. On Feedback Passivity of Discrete-Time Nonlinear Networked Control Systems with Packet Drops

    E-Print Network [OSTI]

    Antsaklis, Panos

    , the system evolves in closed-loop and the increase in storage function is bounded below the energy supplied. #12;2 whose increase in storage function may be greater than the supplied energy at some time steps and the system evolves in closed-loop. Because the process is feedback passive, the resulting increase in storage

  3. Transience, Recurrence and the Speed of a Random Walk in a Site-Based Feedback Environment

    E-Print Network [OSTI]

    Pinsky, Ross

    Transience, Recurrence and the Speed of a Random Walk in a Site-Based Feedback Environment Ross G environment determined by its own trajectory. Sites flip back and forth between two modes, p and q. R environment, whereas for environment. In the critical case

  4. Fourier analysis and systems identification of the p53 feedback loop

    E-Print Network [OSTI]

    to a circuit, measures its output at different frequencies, and describes this by linear models of the dynamicsFourier analysis and systems identification of the p53 feedback loop Naama Geva-Zatorskya,1 , Erez (received for review January 31, 2010) A key circuit in the response of cells to damage is the p53­mdm2

  5. Statistical and dynamical assessment of vegetation feedbacks on climate over the boreal forest

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    in the hydrological cycle include diminished transpiration and moisture recycling, supporting a reduction, the surface albedo was substantially increased. The albedo feedback produced peak cooling in April and weaker cooling in summer. While the cooling due to boreal deforestation was greatest in winter

  6. Closed-loop torque feedback for a universal field-oriented controller

    DOE Patents [OSTI]

    De Doncker, R.W.A.A.; King, R.D.; Sanza, P.C.; Haefner, K.B.

    1992-11-24

    A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation. 1 figure.

  7. Closed-loop torque feedback for a universal field-oriented controller

    SciTech Connect (OSTI)

    De Doncker, Rik W. A. A.; King, Robert D.; Sanza, Peter C.; Haefner, Kenneth B.

    1992-01-01

    A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation.

  8. Measuring Just Noticeable Differences For Haptic Force Feedback: Implications for Rehabilitation

    E-Print Network [OSTI]

    Measuring Just Noticeable Differences For Haptic Force Feedback: Implications for Rehabilitation subjects but none, to our knowledge, has tailored this knowledge to the rehabilitation domain [1 during the course of rehabilitation as a patient's sensory and motor capacities improve or otherwise

  9. Feedback control and optimization for the production of commercial fuels by blending

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    propose can be used in various situations where non-reactive components are blended and linearly impactFeedback control and optimization for the production of commercial fuels by blending M. Ch`ebre, Y presents a control algorithm for blending systems. Such systems are used in refining to produce mixtures

  10. Cardiac Valve Annulus Manual Segmentation Using Computer Assisted Visual Feedback in Three-Dimensional Image Data

    E-Print Network [OSTI]

    Oxford, University of

    Cardiac Valve Annulus Manual Segmentation Using Computer Assisted Visual Feedback in Three is an important tool for the study of valve anatomy and physiology, for the four main valves of the heart (mitral rat hearts, on all four valves. I. INTRODUCTION There are four main cardiac valves in the heart, two

  11. Econometric Feedback for Runtime Risk Management in VoIP Architectures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Econometric Feedback for Runtime Risk Management in VoIP Architectures Oussema Dabbebi, R. Risk management provides new perspectives for addressing this issue. Risk models permit to reduce-configuration strategy for support- ing runtime risk management in VoIP architectures. This strategy aims

  12. OPTIMIZING ENERGY EFFICIENT OF TDMA WITH FINITE RATE FEEDBACK Antonio G. Marques

    E-Print Network [OSTI]

    Marques, Antonio Garcia

    OPTIMIZING ENERGY EFFICIENT OF TDMA WITH FINITE RATE FEEDBACK Antonio G. Marques Dept. of Signal deal with energy efficient time-division multiple access (TDMA) over fading channels with finite approach to iteratively effect energy efficiency. Numerical results are presented to evaluate the energy

  13. Neutral hydrogen in galaxy clusters: impact of AGN feedback and implications for intensity mapping

    E-Print Network [OSTI]

    Villaescusa-Navarro, Francisco; Borgani, Stefano; Viel, Matteo; Rasia, Elena; Murante, Giuseppe; Dolag, Klaus; Steinborn, Lisa K; Biffi, Veronica; Beck, Alexander M; Ragone-Figueroa, Cinthia

    2015-01-01

    By means of zoom-in hydrodynamic simulations we quantify the amount of neutral hydrogen (HI) hosted by groups and clusters of galaxies. Our simulations, which are based on an improved formulation of smoothed particle hydrodynamics (SPH), include radiative cooling, star formation, metal enrichment and supernova feedback, and can be split in two different groups, depending on whether feedback from active galactic nuclei (AGN) is turned on or off. Simulations are analyzed to account for HI self-shielding and the presence of molecular hydrogen. We find that the mass in neutral hydrogen of dark matter halos monotonically increases with the halo mass and can be well described by a power-law of the form $M_{\\rm HI}(M,z)\\propto M^{3/4}$. Our results point out that AGN feedback reduces both the total halo mass and its HI mass, although it is more efficient in removing HI. We conclude that AGN feedback reduces the neutral hydrogen mass of a given halo by $\\sim50\\%$, with a weak dependence on halo mass and redshift. The...

  14. Hybrid Model Predictive Control Based on Wireless Sensor Feedback: An Experimental Study

    E-Print Network [OSTI]

    Johansson, Karl Henrik

    Hybrid Model Predictive Control Based on Wireless Sensor Feedback: An Experimental Study Alberto based on measurements collected by a wireless sensor network. The proposed setup is the prototype of an industrial application in which a remote station controls the process via wireless network links

  15. A survey on the use of relevance feedback for information access systems

    E-Print Network [OSTI]

    Lalmas, Mounia

    1 A survey on the use of relevance feedback for information access systems Ian Ruthven Department Information retrieval (IR) systems allow users to access large amounts of electronically stored information, segments of video or speech samples. A number of features distinguish IR systems from other information

  16. An HNF4a-miRNA Inflammatory Feedback Circuit Regulates

    E-Print Network [OSTI]

    An HNF4a-miRNA Inflammatory Feedback Circuit Regulates Hepatocellular Oncogenesis Maria, once this circuit is activated, it maintains suppression of HNF4a and sustains oncogenesis. Systemic recapitulate hepatic oncogenesis in various animal models (He et al., 2010). In addition, the inflammatory

  17. University of Alberta METHODOLOGIES FOR MANY-INPUT FEEDBACK-DIRECTED

    E-Print Network [OSTI]

    Amaral, José Nelson

    University of Alberta METHODOLOGIES FOR MANY-INPUT FEEDBACK-DIRECTED OPTIMIZATION by Paul Berube Edmonton, Alberta Permission is hereby granted to the University of Alberta Libraries to reproduce single, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other

  18. Feasibility of Locating Tumours in Lung via Kinesthetic Feedback Greig L. McCreery

    E-Print Network [OSTI]

    Naish, Michael D.

    Feasibility of Locating Tumours in Lung via Kinesthetic Feedback Greig L. McCreery Ana Luisa Trejos Michael D. Naish Rajni V. Patel Richard A. Malthaner Abstract Background Localizing lung tumours during-operative imaging cannot map directly to the intra-operative lung. This study analyzes the force sensing performance

  19. Sensorless Adaptive Output Feedback Control of Wind Energy Systems with PMS Generators

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Sensorless Adaptive Output Feedback Control of Wind Energy Systems with PMS Generators A. El the problem of controlling wind energy conversion (WEC) systems involving permanent magnet synchronous is to maximize wind energy extraction which cannot be achieved without letting the wind turbine rotor operate

  20. low graphics version | feedback | help You are in: Sci/Tech

    E-Print Network [OSTI]

    Evers, Läslo G.

    low graphics version | feedback | help You are in: Sci/Tech Front Page World UK UK Politics of the explosion would have been equivalent to 1.5 kilotons of TNT, about the same as a small nuclear weapon to detect the explosions from nuclear weapons. A global network of about 60 infrasound facilities keeps

  1. High-Frequency Auditory Feedback Is Not Required for Adult Song Maintenance in Bengalese Finches

    E-Print Network [OSTI]

    Rubel, Edwin

    High-Frequency Auditory Feedback Is Not Required for Adult Song Maintenance in Bengalese Finches encode high frequen- cies, and low frequencies are encoded in progressively apical regions. We restricted frequencies or those encoding both high and low frequencies and documented resultant changes in song. Birds

  2. Climate and Vegetation in the Middle East: Interannual Variability and Drought Feedbacks

    E-Print Network [OSTI]

    Evans, Jason

    , with the EP exhibiting increased albedo and decreased sensible heat flux while the neighboring Zagros Plateau in latent heat flux. In both the EP and the Zagros there was a potential for positive feedbacks in the Zagros region reduced latent heat flux leads to warming and a deepening of the planetary boundary layer

  3. A symbolic approach to performance analysis of quantized feedback systems: the scalar case

    E-Print Network [OSTI]

    Ceragioli, Francesca

    in the digital control setting and it is indeed a natural way to insert into the control design the complexityA symbolic approach to performance analysis of quantized feedback systems: the scalar case Fabio an essential feature of the control design. The first consequence of the limited information flow constraint

  4. A REAL-TIME ITERATION SCHEME FOR NONLINEAR OPTIMIZATION IN OPTIMAL FEEDBACK CONTROL

    E-Print Network [OSTI]

    " and within the research project "Optimization Based Control of Chemical Processes." httpA REAL-TIME ITERATION SCHEME FOR NONLINEAR OPTIMIZATION IN OPTIMAL FEEDBACK CONTROL MORITZ DIEHL, HANS GEORG BOCK, AND JOHANNES P. SCHL¨ODER SIAM J. CONTROL OPTIM. c 2005 Society for Industrial

  5. DVSleak: Combining Leakage Reduction and Voltage Scaling in Feedback EDF Scheduling

    E-Print Network [OSTI]

    Mueller, Frank

    DVSleak: Combining Leakage Reduction and Voltage Scaling in Feedback EDF Scheduling Yifan Zhu Recent trends in CMOS fabrication have the demand to conserve power of processors. While dynamic voltage fabrication processes are increasingly dominated by static power. For such processors, voltage/frequency pairs

  6. Feedback Control Of An Azimuthal Oscillation In The ExB Discharge of Hall Thrusters

    SciTech Connect (OSTI)

    Griswold, Martin E.; Ellison, C. L.; Raitses, Y.; Fisch, N. J.

    2012-04-06

    Feedback control of a low-frequency azimuthal wave known as a "rotating spoke" in the ExB discharge of a cylindrical Hall thruster was demonstrated. The rotating spoke is an m=1 azimuthal variation in density, electron temperature, and potential that rotates at about 10% of the local E x B electron rotation speed. It causes increased electron transport across the magnetic field and is suspected to be an ionization wave. Feedback control of this wave required special consideration because, although it causes a rotating azimuthal variation in the current density to the anode, it does not show up as a signal in the total thruster discharge current. Therefore, an extra source of information was needed to track the oscillation, which was addressed by using a special anode that was split azimuthally into four segments. The current to each segment oscillates as the rotating spoke passes over it, and feedback is accomplished by resistors connected in series with each anode segment which cause the voltage on a segment to decrease in proportion to the current through that segment. The feedback resulted in the disappearance of a coherent azimuthal wave and a decrease in the time-averaged total discharge current by up to 13.2%.

  7. Carbon limitation of soil respiration under winter snowpacks: potential feedbacks between growing season

    E-Print Network [OSTI]

    Carbon limitation of soil respiration under winter snowpacks: potential feedbacks between growing season and winter carbon fluxes PA U L D . B R O O K S *, D I A N E M C K N I G H T w and K E L LY E L D- latitude and high-elevation ecosystems may increase soil carbon availability both through increased litter

  8. Greening the terrestrial biosphere: simulated feedbacks on atmospheric heat and energy circulation

    E-Print Network [OSTI]

    Cowling, Sharon A.

    Greening the terrestrial biosphere: simulated feedbacks on atmospheric heat and energy circulation on atmospheric exchange of heat and moisture. Our CONTROL simulation had a mean global net primary production (NPP) of 56.3 GtCyr-1 which is half that of our scenario value of 115.1 GtCyr-1 . LAI and latent energy

  9. Feedback based Sparse Recovery for Motion Tracking in RF Sensor Networks

    E-Print Network [OSTI]

    Qiu, Robert Caiming

    Feedback based Sparse Recovery for Motion Tracking in RF Sensor Networks Heping Song #1 , Tong Liu #2 , Xiaomu Luo #3 , Guoli Wang #4 # School of Information Science and Technology, Sun Yat tracking with radio tomographic networks using received signal strength (RSS) measurements has attracted

  10. Surface energy exchanges along a tundra-forest transition and feedbacks to climate

    E-Print Network [OSTI]

    McGuire, A. David

    Surface energy exchanges along a tundra-forest transition and feedbacks to climate Jason Beringer a 21 October 2004; accepted 17 May 2005 Abstract Surface energy exchanges were measured in a sequence of five sites representing the major vegetation types in the transition from arctic tundra to forest

  11. Mixed-mode dynamics in a semiconductor laser with two optical feedbacks

    E-Print Network [OSTI]

    Sukow, David W.

    , is to record power and optical spectra whose interpretation can reveal the system's dynamics. Frequency intensities are induced even at extremely low feedback rates. The large coupling of the phase of the electric produces dynamics at picosecond timescales and makes it relatively hard to record accurate time series

  12. A Hybrid Feedback Regulator Approach to Control an Automotive Suspension System

    E-Print Network [OSTI]

    Koutsoukos, Xenofon D.

    A Hybrid Feedback Regulator Approach to Control an Automotive Suspension System Xenofon D synthe- sis approach using an automotive suspension system. Discrete abstrac- tions are used control synthesis is presented and an example of an automotive suspension system is used to illus- trate

  13. L1=Q Approach for efficient computation of disturbance rejection measures for feedback control q

    E-Print Network [OSTI]

    Skogestad, Sigurd

    L1=Q Approach for efficient computation of disturbance rejection measures for feedback control q of disturbance rejection measures, which are useful for assessing the dynamic operability of the process. Using L1 optimal control theory, we consider the cases of steady-state, frequency-wise and dynamic systems

  14. Drive-by Motor Vehicle Emissions: Immediate Feedback in Reducing Air

    E-Print Network [OSTI]

    Denver, University of

    Drive-by Motor Vehicle Emissions: Immediate Feedback in Reducing Air Pollution G A R Y A . B I S H, Denver, Colorado 80208 L E N O R A B O H R E N The National Center for Vehicle Emissions Control & Safety of vehicle emissions information system has been developed which utilizes an innovative variable message sign

  15. A New Bulk Shallow-Cumulus Model and Implications for Penetrative Entrainment Feedback on Updraft Buoyancy

    E-Print Network [OSTI]

    Bretherton, Chris

    A New Bulk Shallow-Cumulus Model and Implications for Penetrative Entrainment Feedback on Updraft than prognosing, the cumulus-layer gradients and introducing a penetrative entrainment closure assumptions about lateral cumulus entrainment and detrainment and a simplified sub-cloud-layer entrainment

  16. Feedback Control of the National Airspace System to Mitigate Weather Disruptions

    E-Print Network [OSTI]

    Le Ny, Jerome

    Feedback Control of the National Airspace System to Mitigate Weather Disruptions Jerome Le Ny during a weather event, given a probabilistic forecast of capacities. We also address the management to weather disruptions. I. INTRODUCTION The frequent occurrence of air traffic delays in the Na- tional

  17. Narrowing of high power diode laser arrays using reflection feedback from an etalon

    E-Print Network [OSTI]

    Romalis, Mike

    Narrowing of high power diode laser arrays using reflection feedback from an etalon M. V. Romalisa for publication 27 June 2000 The spectrum of a high power multielement laser array is narrowed using reflection of the laser array is reduced by a factor of 2 with only 6% power loss. This reduction in FWHM is useful

  18. A Wireless Lingual Feedback Device to Reduce Overpressures in Seated Posture: A Feasibility Study

    E-Print Network [OSTI]

    Payan, Yohan

    A Wireless Lingual Feedback Device to Reduce Overpressures in Seated Posture: A Feasibility Study) a laptop coupling sensors and actuator (3) a wireless Tongue Display Unit (TDU) consisting of a circuit subjects initially formed the experimental group (EG) and were seated on a chair with the wireless TDU

  19. Adaptive Routing with End-to-End feedback: Distributed Learning and Geometric Approaches

    E-Print Network [OSTI]

    Kleinberg, Robert D.

    algorithm must choose, in each round, a strategy from some compact set S Rd so as to try to minimize a linear cost function which is only revealed at the end of the round. Kalai and Vempala [4] gave an algorithm for such problems in the transparent feedback model, where the entire cost function is revealed

  20. A Study of Feedback Strategies in Foreign Language Classrooms and Tutorials with Implications for Intelligent Computer-Assisted Language Learning Systems 

    E-Print Network [OSTI]

    Ferreira Cabrera, Anita; Moore, Johanna D.; Mellish, Chris

    This paper presents two new corpus-based studies of feedback in the domain of teaching Spanish as a foreign language, concentrating on the type and frequency of different feedback moves, as well as what happens in the ...

  1. Correlation between present-day model simulation of Arctic cloud radiative forcing and sea ice consistent with positive winter convective cloud feedback

    E-Print Network [OSTI]

    Emanuel, Kerry Andrew

    A positive feedback on winter sea-ice loss, based on warming due to radiative forcing caused by the onset of convective clouds in response to sea-ice loss, has recently been proposed. This feedback has thus far been ...

  2. Internal pipe attachment mechanism

    DOE Patents [OSTI]

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  3. MechanicalEngineering Colloquium The Department of Mechanical

    E-Print Network [OSTI]

    MechanicalEngineering Colloquium The Department of Mechanical Engineering PRESENTS John C. Bischof Distinguished Professor Mechanical and Biomedical Engineering Chair, Mechanical Engineering University in the Departments of Mechanical and Biomedical Engineering and the inaugural Carl and Janet Kuhrmeyer Chair

  4. Modeling jet and outflow feedback during star cluster formation

    SciTech Connect (OSTI)

    Federrath, Christoph; Schrön, Martin; Banerjee, Robi; Klessen, Ralf S.

    2014-08-01

    Powerful jets and outflows are launched from the protostellar disks around newborn stars. These outflows carry enough mass and momentum to transform the structure of their parent molecular cloud and to potentially control star formation itself. Despite their importance, we have not been able to fully quantify the impact of jets and outflows during the formation of a star cluster. The main problem lies in limited computing power. We would have to resolve the magnetic jet-launching mechanism close to the protostar and at the same time follow the evolution of a parsec-size cloud for a million years. Current computer power and codes fall orders of magnitude short of achieving this. In order to overcome this problem, we implement a subgrid-scale (SGS) model for launching jets and outflows, which demonstrably converges and reproduces the mass, linear and angular momentum transfer, and the speed of real jets, with ?1000 times lower resolution than would be required without the SGS model. We apply the new SGS model to turbulent, magnetized star cluster formation and show that jets and outflows (1) eject about one-fourth of their parent molecular clump in high-speed jets, quickly reaching distances of more than a parsec, (2) reduce the star formation rate by about a factor of two, and (3) lead to the formation of ?1.5 times as many stars compared to the no-outflow case. Most importantly, we find that jets and outflows reduce the average star mass by a factor of ? three and may thus be essential for understanding the characteristic mass of the stellar initial mass function.

  5. Feedback-Driven Evolution of the Far-Infrared Spectral Energy Distributions of Luminous and Ultraluminous Infrared Galaxies

    E-Print Network [OSTI]

    Sukanya Chakrabarti; T. J. Cox; Lars Hernquist; Philip F. Hopkins; Brant Robertson; Tiziana Di Matteo

    2007-01-22

    We calculate infrared spectral energy distributions (SEDs) from simulations of major galaxy mergers and study the effect of AGN and starburst driven feedback on the evolution of the SED as a function of time. We use a self-consistent three-dimensional radiative equilibrium code to calculate the emergent SEDs and to make images. To facilitate a simple description of our findings, we describe our results in reference to an approximate analytic solution for the far-IR SED. We focus mainly on the luminous infrared galaxy (LIRG) and ultraluminous infrared galaxy (ULIRG) phases of evolution. We contrast the SEDs of simulations performed with AGN feedback to simulations performed with starburst driven wind feedback. We find that the feedback processes critically determine the evolution of the SED. Changing the source of illumination (whether stellar or AGN) has virtually no impact on the reprocessed far-infrared SED. We find that AGN feedback is particularly effective at dispersing gas and rapidly injecting energy into the ISM. The observational signature of such powerful feedback is a warm SED. In general, simulations performed with starburst driven winds have colder spectra and reprocess more of their emission into the infrared, resulting in higher infrared to bolometric luminosities compared to (otherwise equivalent) simulations performed with AGN feedback. We depict our results in IRAS bands, as well as in Spitzer's MIPS bands, and in Herschel's PACS bands.

  6. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering We introduce phonon recycling (local reabsorption of emitted) is Professor in Department of Mechanical Engineering and in Applied Physics Program, University of Michigan of Mechanical Engineering University of Michigan November 1, 2013 at 1:30pm in SCOB 228 School for Engineering

  7. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Manipulation of Energy and Mass Transport at Micro as an assistant professor in the Department of Mechanical Engineering and was promoted to an associate professor award in 2007. Dr. Deyu Li Department of Mechanical Engineering Vanderbilt University January 20, 2012

  8. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Thermal transport plays an important role in energy conversion conductivity and phonon transport mechanisms over the past 2 decades, owing much to the challenging needs Faculty Fellow in Engineering and an Associate Professor of Mechanical Engineering directing the Nano

  9. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Interfacial flows are multi-material flows comprised of two and Solid Mechanics group in the Theoretical Division. Her research focuses on the development of numerical, and nuclear energy. She is a member of the American Society of Mechanical Engineers (ASME), Fluids Engineering

  10. Department of Mechanical and

    E-Print Network [OSTI]

    Huang, Jianwei

    Department of Mechanical and Automation Engineering #12;4 2 3 1 Contents Messages in the souvenir publication of the Department of Mechanical and Automation Engineering of The Chinese University of Mechanical and Automation Engineering have also played a significant part in equipping businesses

  11. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Much of past research in structural dynamics (and many other the University of Liege, Belgium, in 1983 and his Ph.D. in mechanical engineering from Rice University in 1987. He then joined the rather newly formed Department of Mechanical and Aerospace Engineering at ASU

  12. TOWARDS MECHANICAL METAMATHEMATICS

    E-Print Network [OSTI]

    Boyer, Robert Stephen

    TOWARDS MECHANICAL METAMATHEMATICS N. Shankar Technical Report 43 December 1984 Institute application of certain mechanical rules of inference. The derivations of theorems from the axioms are termed of a valid mathematical argument. Another advantage of formal proofs is that they can be mechanically checked

  13. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering It has been demonstrated that the color pattern of the human received the B.A. degree in physics from Houghton College, Houghton, NY, and the B.S. degree in mechanical in mechanical engineering from the Massachusetts Institute of Technology (MIT), Cambridge, MA, in 1997 and 2002

  14. A mechanical encapsulatio n

    E-Print Network [OSTI]

    Jackson, Trachette L.

    A mechanical mo delo f tumo r encapsulatio n and transcapsular spread Trachette L. Jackso n a 48109­1109, USA b Division of Theoretical Mechanics, School of Mathematical Sciences, University rmatio n, such investigatio ns being ideally suited to o ur mechanical mo del. The mo del simulatio ns

  15. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Fragmentation is a process in which structures fail in a very Engineering at Duke University, where he directs the Duke Computational Mechanics Laboratory. Professor Dolbow received his BS in Mechanical Engineering from the University of New Hampshire in 1995, and his Ph

  16. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The miniaturization of structural components to the sub progress in strain-gradient continuum theories to model the mechanical behavior of metallic systems at small length scales, these theories fail to represent the variety of physical mechanisms involved

  17. Mechanical Engineering Assistant Professor

    E-Print Network [OSTI]

    Chandy, John A.

    Mechanical Engineering Xu Chen Assistant Professor xchen@uconn.edu http://xchen.lab.uconn.edu From Engineering Ingredients of Kung Pao Chicken Marinade · 1 tablespoon soy sauce · 2 teaspoons Chinese rice wine of Diana Kuan #12;Mechanical Engineering The Cooking Procedure #12;Mechanical Engineering The Difference

  18. Mechanical & Industrial Engineering

    E-Print Network [OSTI]

    Mountziaris, T. J.

    Mechanical & Industrial Engineering Mario A. Rotea Professor and Department Head #12;2Mechanical & Industrial Engineering Outline · Undergraduate Degree Programs · Graduate Degree Programs · The Faculty · The Research · Summary #12;3Mechanical & Industrial Engineering Undergraduate Programs ­ BSME & BSIE 0 20 40 60

  19. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Pool boiling heat transfer enhancement is taking a dramatic turn Mechanical Engineering Rochester Institute of Technology September 5, 2014 at 1:30pm in SCOB 210 School from the classical area enhancement and nucleation cavity augmentation to mechanism based

  20. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering Energetic materials that include nano-scale aluminum (Al and joined the faculty in the Mechanical Engineering Department at Texas Tech University in 2000 Pantoya Dept. of Mechanical Engineering Texas Tech University April 19, 2013 at 1:30pm in LSE 106 School

  1. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The presentation will first review emerging joint time in Mechanical Engineering and Engineering Science from the Technical University in Athens, Greece and his, vehicle engineering, bio-mechanics, and composite materials. He is Editor-in-Chief of the International

  2. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The state of the art in Quantification of Margin and UncertaintyD in Engineering Mechanics from the University of Wisconsin in 1978. He then worked in research laboratories of the University of Wisconsin as a Senior Scientist. In March of this year, he joined the Mechanical Engineering

  3. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar From Jumping Drops to Thermal Diodes Abstract Scholar and Assistant Professor of Mechanical Engineering and Materials Science at Duke University since.D. degree in Mechanical Engineering from Stanford University (2004). Dr. Chen is a recipient of numerous

  4. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Some Forward-Looking Assistive Devices to Improve. Biosketch Michael Goldfarb, PhD, is the H. Fort Flowers Professor of Mechanical Engineering and the director in Mechanical Engineering from the University of Arizona in 1988, and received his SM and PhD degrees

  5. Mechanical and Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical and Aerospace Engineering seminar Plasma Actuators for Aerodynamic Flow Control.D. in Mechanical Engineering from The Ohio State University in 2004, 2005 and 2010 respectively. He joined the Department of Aerospace and Mechanical Engineering at the University of Arizona in 2010 as an Assistant

  6. Mechanical & Aerospace Engineering

    E-Print Network [OSTI]

    Mechanical & Aerospace Engineering The atomization of a liquid jet by a high speed cross.S.E. degree in mechanical engineering from Amirkabir University of Technology in 2006 and M.S. degree in mechanical engineering from Sharif University of Technology in 2009. He is currently a Ph.D. candidate

  7. QUICK QUANTUM MECHANICS ---Introduction ---

    E-Print Network [OSTI]

    Jackson, Andrew D.

    QUICK QUANTUM MECHANICS --- Introduction --- The following notes are intended to be a supplement to your study of Liboff's ``Introductory Quantum Mechanics.'' They are not an alternative! My purpose here of Classical Mechanics After Newton found his equations of motion, physicists knew they would have to wait

  8. Introduction to Quantum Mechanics

    E-Print Network [OSTI]

    Eduardo J. S. Villaseñor

    2008-04-23

    The purpose of this contribution is to give a very brief introduction to Quantum Mechanics for an audience of mathematicians. I will follow Segal's approach to Quantum Mechanics paying special attention to algebraic issues. The usual representation of Quantum Mechanics on Hilbert spaces is also discussed.

  9. Mechanical Systems Signal Processing

    E-Print Network [OSTI]

    Carvalho, João B.

    , Northern Illinois University, DeKalb, IL 60115, USA c Department of Mechanical Engineering & VibrationMechanical Systems and Signal Processing Mechanical Systems and Signal Processing 21 (2007) 2715 Federal de Rio Grande do Sul, Brazil b Department of Mathematical Sciences & Vibration and Acoustic Center

  10. Dynamical behavior of the motions associated with the nonlinear periodic regime in a laboratory plasma subject to delayed feedback

    SciTech Connect (OSTI)

    Fukuyama, T.; Shirahama, H. [Faculty of Education, Ehime University, Bunkyo-cho 3, Matsuyama, Ehime 790-8577 (Japan); Watanabe, Y.; Kawai, Y. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasugakoen 6-1, Kasuga, Fukuoka 816-8580 (Japan); Taniguchi, K. [Department of Physics, Kyoto University of Education, Fujinomori-cho 1, Fukakusa, Fushimi-ku, Kyoto 612-8522 (Japan)

    2006-07-15

    Time-delayed feedback is applied to the motions associated with the nonlinear periodic regime generated due to current-driven ion acoustic instability; this is a typical instability in a laboratory plasma, and the dynamical behavior is experimentally investigated using delayed feedback. A time-delayed autosynchronization method is applied. When delayed feedback is applied to the nonlinear periodic orbit, the periodic state changes to various motions depending on the control parameters, namely, the arbitrary time delay and the proportionality constant. Lyapunov exponents are calculated in order to examine the dynamical behavior.

  11. Mechanical seal assembly

    DOE Patents [OSTI]

    Kotlyar, Oleg M. (Salt Lake City, UT)

    2002-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transfering it to the mechanical diode.

  12. Mechanical seal assembly

    DOE Patents [OSTI]

    Kotlyar, Oleg M. (Salt Lake City, UT)

    2001-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

  13. Next Generation Environmentally-Friendly Driving Feedback Systems Research and Development

    SciTech Connect (OSTI)

    Barth, Matthew; Boriboonsomsin, Kanok

    2014-12-31

    The objective of this project is to design, develop, and demonstrate a next-generation, federal safety- and emission-complaint driving feedback system that can be deployed across the existing vehicle fleet and improve fleet average fuel efficiency by at least 2%. The project objective was achieved with the driving feedback system that encourages fuel-efficient vehicle travel and operation through: 1) Eco-Routing Navigation module that suggests the most fuel-efficient route from one stop to the next, 2) Eco-Driving Feedback module that provides sensible information, recommendation, and warning regarding fuel-efficient vehicle operation, and 3) Eco-Score and Eco-Rank module that provides a means for driving performance tracking, self-evaluation, and peer comparison. The system also collects and stores vehicle travel and operation data, which are used by Algorithm Updating module to customize the other modules for specific vehicles and adapts them to specific drivers over time. The driving feedback system was designed and developed as an aftermarket technology that can be retrofitted to vehicles in the existing fleet. It consists of a mobile application for smart devices running Android operating system, a vehicle on-board diagnostics connector, and a data server. While the system receives and utilizes real-time vehicle and engine data from the vehicle’s controller area network bus through the vehicle’s on-board diagnostic connector, it does not modify or interfere with the vehicle’s controller area network bus, and thus, is in compliance with federal safety and emission regulations. The driving feedback system was demonstrated and then installed on 45 vehicles from three different fleets for field operational test. These include 15 private vehicles of the general public, 15 pickup trucks of the California Department of Transportation that are assigned to individual employees for business use, and 15 shuttle buses of the Riverside Transit Agency that are used for paratransit service. Detailed vehicle travel and operation data including route taken, driving speed, acceleration, braking, and the corresponding fuel consumption, were collected both before and during the test period. The data analysis results show that the fleet average fuel efficiency improvements for the three fleets with the use of the driving feedback system are in the range of 2% to 9%. The economic viability of the driving feedback system is high. A fully deployed system would require capital investment in smart device ($150-$350) and on-board diagnostics connector ($50-$100) as well as paying operating costs for wireless data plan and subscription fees ($20-$30 per month) for connecting to the data server and receiving various system services. For individual consumers who already own a smart device (such as smartphone) and commercial fleets that already use some kind of telematics services, the costs for deploying this driving feedback system would be much lower.

  14. Gusty, gaseous flows of FIRE: galactic winds in cosmological simulations with explicit stellar feedback

    E-Print Network [OSTI]

    Muratov, Alexander L; Faucher-Giguere, Claude-Andre; Hopkins, Philip F; Quataert, Eliot; Murray, Norman

    2015-01-01

    We present an analysis of the galaxy-scale gaseous outflows from the FIRE (Feedback in Realistic Environments) simulations. This suite of hydrodynamic cosmological zoom simulations provides a sample of halos where star-forming giant molecular clouds are resolved to z=0, and features an explicit stellar feedback model on small scales. In this work, we focus on quantifying the gas mass ejected out of galaxies in winds and how this material travels through the halo. We correlate these quantities to star formation in galaxies throughout cosmic history. Our simulations reveal that a significant portion of every galaxy's evolution, particularly at high redshift, is dominated by bursts of star formation, which are followed by powerful gusts of galactic outflow that sweep up a large fraction of gas in the interstellar medium and send it through the circumgalactic medium. The dynamical effect of these outflows can significantly limit the amount of star formation within the affected galaxy. At low redshift, however, su...

  15. Globular cluster formation efficiencies from black-hole X-ray binary feedback

    E-Print Network [OSTI]

    Justham, Stephen; Schawinski, Kevin

    2015-01-01

    We investigate a scenario in which feedback from black-hole X-ray binaries (BHXBs) sometimes begins inside young star clusters before strong supernova feedback. Those BHXBs could reduce the gas fraction inside embedded young clusters whilst maintaining virial equilibrium, which may help globular clusters (GCs) to stay bound when supernova-driven gas ejection subsequently occurs. Adopting a simple toy model with parameters guided by BHXB population models, we produce GC formation efficiencies consistent with empirically-inferred values. The metallicity dependence of BHXB formation could naturally explain why GC formation efficiency is higher at lower metallicity. For reasonable assumptions about that metallicity dependence, our toy model can produce a GC metallicity bimodality in some galaxies without a bimodality in the field-star metallicity distribution.

  16. Refuting the odd number limitation of time-delayed feedback control

    E-Print Network [OSTI]

    B. Fiedler; V. Flunkert; M. Georgi; P. Hoevel; E. Schoell

    2007-02-12

    We refute an often invoked theorem which claims that a periodic orbit with an odd number of real Floquet multipliers greater than unity can never be stabilized by time-delayed feedback control in the form proposed by Pyragas. Using a generic normal form, we demonstrate that the unstable periodic orbit generated by a subcritical Hopf bifurcation, which has a single real unstable Floquet multiplier, can in fact be stabilized. We derive explicit analytical conditions for the control matrix in terms of the amplitude and the phase of the feedback control gain, and present a numerical example. Our results are of relevance for a wide range of systems in physics, chemistry, technology,and life sciences, where subcritical Hopf bifurcations occur.

  17. Optimized Multi-Frequency Spectra for Applications in Radiative Feedback and Cosmological Reionization

    E-Print Network [OSTI]

    Mirocha, Jordan; Burns, Jack O; Wise, John H

    2012-01-01

    The recent implementation of radiative transfer algorithms in numerous hydrodynamics codes has led to a dramatic improvement in studies of feedback in various astrophysical environments. However, because of methodological limitations and computational expense, the spectra of radiation sources are generally sampled at only a few evenly-spaced discrete emission frequencies. Using 1D radiative transfer calculations, we investigate the discrepancies in gas properties surrounding model stars and accreting black holes that arise solely due to spectral discretization. We find that even in the idealized case of a static and uniform density field, commonly used discretization schemes induce errors in the neutral fraction and temperature by factors of 2-3 on average, and by over an order of magnitude in certain column density regimes. The consequences are most severe for radiative feedback operating on large scales, dense clumps of gas, and media consisting of multiple chemical species. We have developed a method for o...

  18. Feedback following the Industry Engagement of the NNSA Unique Identifier and Global Monitoring 5 year plan

    SciTech Connect (OSTI)

    White-Horton, Jessica L; Whitaker, J Michael; Durbin, Karyn R.

    2013-01-01

    The National Nuclear Security Administration s project for developing a unique identifier and a concept for a global monitoring system for UF6 cylinders made significant progress on developing functional requirements and a concept of operation for such a system. The multi-laboratory team is working to define the functional requirements for both the unique identifier and the global monitoring system and to develop a preliminary concept of operations to discuss with key industry stakeholders. Team members began meeting with industry representatives in January 2013 to discuss the preliminary concept and solicit feedback and suggestions. The team has met with representatives from United States Enrichment Corporation, Cameco, URENCO, Honeywell/ConverDyn, and others. This paper presents an overview of the preliminary concept of operations and shares the feedback obtained from the industry engagement meetings.

  19. Generation of flat-top pulsed magnetic fields with feedback control approach

    E-Print Network [OSTI]

    Kohama, Yoshimitsu

    2015-01-01

    We describe the construction of a simple, compact, and cost-effective feedback system that produces flat-top field profiles in pulsed magnetic fields. This system is designed for use in conjunction with a typical capacitor-bank driven pulsed magnet, and was tested using a 60-T pulsed magnet. With the developed feedback controller, we have demonstrated flat-top magnetic fields as high as 60.64 T with an excellent field stability of +-0.005 T. The result indicates that the flat-top pulsed magnetic field produced features high field stability and an accessible field strength. These features make this system useful for improving the resolution of data with signal averaging.

  20. Nonlinear power flow feedback control for improved stability and performance of airfoil sections

    DOE Patents [OSTI]

    Wilson, David G.; Robinett, III, Rush D.

    2013-09-03

    A computer-implemented method of determining the pitch stability of an airfoil system, comprising using a computer to numerically integrate a differential equation of motion that includes terms describing PID controller action. In one model, the differential equation characterizes the time-dependent response of the airfoil's pitch angle, .alpha.. The computer model calculates limit-cycles of the model, which represent the stability boundaries of the airfoil system. Once the stability boundary is known, feedback control can be implemented, by using, for example, a PID controller to control a feedback actuator. The method allows the PID controller gain constants, K.sub.I, K.sub.p, and K.sub.d, to be optimized. This permits operation closer to the stability boundaries, while preventing the physical apparatus from unintentionally crossing the stability boundaries. Operating closer to the stability boundaries permits greater power efficiencies to be extracted from the airfoil system.