Tuning the Stiffness Balance Using Characteristic Frequencies as a Criterion for a Superconducting Gravity Gradiometer

PubMed Central

Liu, Xikai; Ma, Dong; Chen, Liang; Liu, Xiangdong

2018-01-01

Tuning the stiffness balance is crucial to full-band common-mode rejection for a superconducting gravity gradiometer (SGG). A reliable method to do so has been proposed and experimentally tested. In the tuning scheme, the frequency response functions of the displacement of individual test mass upon common-mode accelerations were measured and thus determined a characteristic frequency for each test mass. A reduced difference in characteristic frequencies between the two test masses was utilized as the criterion for an effective tuning. Since the measurement of the characteristic frequencies does not depend on the scale factors of displacement detection, stiffness tuning can be done independently. We have tested this new method on a single-component SGG and obtained a reduction of two orders of magnitude in stiffness mismatch. PMID:29419796

Optimal placement of tuning masses on truss structures by genetic algorithms

NASA Technical Reports Server (NTRS)

Ponslet, Eric; Haftka, Raphael T.; Cudney, Harley H.

1993-01-01

Optimal placement of tuning masses, actuators and other peripherals on large space structures is a combinatorial optimization problem. This paper surveys several techniques for solving this problem. The genetic algorithm approach to the solution of the placement problem is described in detail. An example of minimizing the difference between the two lowest frequencies of a laboratory truss by adding tuning masses is used for demonstrating some of the advantages of genetic algorithms. The relative efficiencies of different codings are compared using the results of a large number of optimization runs.

Earthquake Damping Device for Steel Frame

NASA Astrophysics Data System (ADS)

Zamri Ramli, Mohd; Delfy, Dezoura; Adnan, Azlan; Torman, Zaida

2018-04-01

Structures such as buildings, bridges and towers are prone to collapse when natural phenomena like earthquake occurred. Therefore, many design codes are reviewed and new technologies are introduced to resist earthquake energy especially on building to avoid collapse. The tuned mass damper is one of the earthquake reduction products introduced on structures to minimise the earthquake effect. This study aims to analyse the effectiveness of tuned mass damper by experimental works and finite element modelling. The comparisons are made between these two models under harmonic excitation. Based on the result, it is proven that installing tuned mass damper will reduce the dynamic response of the frame but only in several input frequencies. At the highest input frequency applied, the tuned mass damper failed to reduce the responses. In conclusion, in order to use a proper design of damper, detailed analysis must be carried out to have sufficient design based on the location of the structures with specific ground accelerations.

Photolithography and Selective Etching of an Array of Quartz Tuning Fork Resonators with Improved Impact Resistance Characteristics

NASA Astrophysics Data System (ADS)

Lee, Sungkyu

2001-08-01

Quartz tuning fork blanks with improved impact-resistant characteristics for use in Qualcomm mobile station modem (MSM)-3000 central processing unit (CPU) chips for code division multiple access (CDMA), personal communication system (PCS), and global system for mobile communication (GSM) systems were designed using finite element method (FEM) analysis and suitable processing conditions were determined for the reproducible precision etching of a Z-cut quartz wafer into an array of tuning forks. Negative photoresist photolithography for the additive process was used in preference to positive photoresist photolithography for the subtractive process to etch the array of quartz tuning forks. The tuning fork pattern was transferred via a conventional photolithographical chromium/quartz glass template using a standard single-sided aligner and subsequent negative photoresist development. A tightly adhering and pinhole-free 600/2000 Å chromium/gold mask was coated over the developed photoresist pattern which was subsequently stripped in acetone. This procedure was repeated on the back surface of the wafer. With the protective metallization area of the tuning fork geometry thus formed, etching through the quartz wafer was performed at 80°C in a ± 1.5°C controlled bath containing a concentrated solution of ammonium bifluoride to remove the unwanted areas of the quartz wafer. The quality of the quartz wafer surface finish after quartz etching depended primarily on the surface finish of the quartz wafer prior to etching and the quality of quartz crystals used. Selective etching of a 100 μm quartz wafer could be achieved within 90 min at 80°C. A selective etching procedure with reproducible precision has thus been established and enables the photolithographic mass production of miniature tuning fork resonators.

On a Self-Tuning Impact Vibration Damper for Rotating Turbomachinery

NASA Technical Reports Server (NTRS)

Duffy, Kirsten P.; Bagley, Ronald L.; Mehmed, Oral; Choi, Ben (Technical Monitor)

2000-01-01

A self-tuning impact damper is investigated analytically and experimentally as a device to inhibit vibration and increase the fatigue life of rotating components in turbomachinery. High centrifugal loads in rotors can inactivate traditional impact dampers because of friction or misalignment of the damper in the g-field. Giving an impact damper characteristics of an acceleration tuned-mass damper enables the resulting device to maintain damper mass motion and effectiveness during high-g loading. Experimental results presented here verify that this self-tuning impact damper can be designed to follow an engine order line. damping rotor component resonance crossings.

Smart Novel Semi-Active Tuned Mass Damper for Fixed-Bottom and Floating Offshore Wind (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez Tsouroukdissian, Arturo

2016-05-02

The intention of this paper is to present the results of a novel smart semi-active tuned mass damper (SA-TMD), which mitigates unwanted loads for both fixed-bottom and floating offshore wind systems. (Presentation Format).

Improving automatic peptide mass fingerprint protein identification by combining many peak sets.

PubMed

Rögnvaldsson, Thorsteinn; Häkkinen, Jari; Lindberg, Claes; Marko-Varga, György; Potthast, Frank; Samuelsson, Jim

2004-08-05

An automated peak picking strategy is presented where several peak sets with different signal-to-noise levels are combined to form a more reliable statement on the protein identity. The strategy is compared against both manual peak picking and industry standard automated peak picking on a set of mass spectra obtained after tryptic in gel digestion of 2D-gel samples from human fetal fibroblasts. The set of spectra contain samples ranging from strong to weak spectra, and the proposed multiple-scale method is shown to be much better on weak spectra than the industry standard method and a human operator, and equal in performance to these on strong and medium strong spectra. It is also demonstrated that peak sets selected by a human operator display a considerable variability and that it is impossible to speak of a single "true" peak set for a given spectrum. The described multiple-scale strategy both avoids time-consuming parameter tuning and exceeds the human operator in protein identification efficiency. The strategy therefore promises reliable automated user-independent protein identification using peptide mass fingerprints.

Multiple model self-tuning control for a class of nonlinear systems

NASA Astrophysics Data System (ADS)

Huang, Miao; Wang, Xin; Wang, Zhenlei

2015-10-01

This study develops a novel nonlinear multiple model self-tuning control method for a class of nonlinear discrete-time systems. An increment system model and a modified robust adaptive law are proposed to expand the application range, thus eliminating the assumption that either the nonlinear term of the nonlinear system or its differential term is global-bounded. The nonlinear self-tuning control method can address the situation wherein the nonlinear system is not subject to a globally uniformly asymptotically stable zero dynamics by incorporating the pole-placement scheme. A novel, nonlinear control structure based on this scheme is presented to improve control precision. Stability and convergence can be confirmed when the proposed multiple model self-tuning control method is applied. Furthermore, simulation results demonstrate the effectiveness of the proposed method.

Wave propagation in elastic and damped structures with stabilized negative-stiffness components

NASA Astrophysics Data System (ADS)

Drugan, W. J.

2017-09-01

Effects on wave propagation achievable by introduction of a negative-stiffness component are investigated via perhaps the simplest discrete repeating element that can remain stable in the component's presence. When the system is elastic, appropriate tuning of the stabilized component's negative stiffness introduces a no-pass zone theoretically extending from zero to an arbitrarily high frequency, tunable by a mass ratio adjustment. When the negative-stiffness component is tuned to the system's stability limit and a mass ratio is sufficiently small, the system restricts propagation to waves of approximately a single arbitrary frequency, adjustable by tuning the stiffness ratio of the positive-stiffness components. The elastic system's general solutions are closed-form and transparent. When damping is added, the general solutions are still closed-form, but so complex that they do not clearly display how the negative stiffness component affects the system's response and how it should best be tuned to achieve desired effects. Approximate solutions having these features are obtained via four perturbation analyses: one for long wavelengths; one for small damping; and two for small mass ratios. The long-wavelengths solution shows that appropriate tuning of the negative-stiffness component can prevent propagation of long-wavelength waves. The small damping solution shows that the zero-damping low-frequency no-pass zone remains, while waves that do propagate are highly damped when a mass ratio is made small. Finally, very interesting effects are achievable at the full system's stability limit. For small mass ratios, the wavelength range of waves prohibited from propagation can be adjusted, from all to none, by tuning the system's damping: When one mass ratio is small, all waves with wavelengths larger than an arbitrary damping-adjusted value can be prohibited from propagation, while when the inverse of this mass ratio is small, all waves with wavelengths outside an arbitrary single adjustable value or range of values can be prohibited from propagation. All of the approximate solutions' analytically-transparent predictions are confirmed by the exact solution. The conclusions are that a stabilized tuned negative-stiffness component greatly enhances control of wave propagation in a purely elastic system, and when adjustable damping is added, even further control is facilitated.

Light stops and fine-tuning in MSSM

NASA Astrophysics Data System (ADS)

Çiçi, Ali; Kırca, Zerrin; Ün, Cem Salih

2018-01-01

We discuss the fine-tuning issue within the MSSM framework. Following the idea that the fine-tuning can measure effects of some missing mechanism, we impose non-universal gaugino masses at the GUT scale, and explore the low scale implications. We realize that the fine-tuning parametrized with Δ _{EW} can be as low as zero. We consider the stop mass with a special importance and focus on the mass scales as m_{\\tilde{t}} ≤ 700 GeV, which are excluded by the current experiments when the stop decays into a neutralino along with a top quark or a chargino along with a bottom quark. We find that the stop mass can be as low as about 250 GeV with Δ _{EW} ˜ 50. We find that the solutions in this region can be exluded only up to 60% when stop decays into a neutralino-top quark, and 50% when it decays into a chargino-b quark. Setting 65% CL to be potential exclusion and 95% to be pure exclusion limit such solutions will be tested in near future experiments, which are conducted with higher luminosity. In addition to stop, the region with low fine-tuning and light stops predicts masses for the other supersymmetric particles such as m_{\\tilde{b}} ≳ 700 GeV, m_{\\tilde{τ }} ≳ 1 TeV, m_{\\tilde{χ }1^{± }} ≳ 120 GeV. The details for the mass scales and decay rates are also provided by tables of benchmark points.

Application of tuned mass dampers in high-rise construction

NASA Astrophysics Data System (ADS)

Teplyshev, Vyacheslav; Mylnik, Alexey; Pushkareva, Maria; Agakhanov, Murad; Burova, Olga

2018-03-01

The article considers the use of tuned mass dampers in high-rise construction for significant acceleration and amplitude of vibrations of the upper floors under dynamic wind influences. The susceptibility of people to accelerations in high-rise buildings and possible means of reducing wind-induced fluctuations in buildings are analyzed. The statistics of application of tuned mass dampers in high-rise construction all over the world is presented. The goal of the study is to identify an economically attractive solution that allows the fullest use of the potential of building structures in high-rise construction, abandoning the need to build massive frames leading to over-consumption of materials.

Effects of Swept Tips on V-22 Whirl Flutter and Loads

NASA Technical Reports Server (NTRS)

Acree, C. W., Jr.

2005-01-01

A CAMRAD II model of the V-22 Osprey tiltrotor was constructed for the purpose of analyzing the effects of blade design changes on whirl flutter. The model incorporated a dual load-path grip/yoke assembly, a swashplate coupled to the transmission case, and a drive train. A multiple-trailer free wake was used for loads calculations. The effects of rotor design changes on whirl-mode stability were calculated for swept blades and offset tip masses. A rotor with swept tips and inboard tuning masses was examined in detail to reveal the mechanisms by which these design changes affect stability and loads. Certain combinations of design features greatly increased whirl-mode stability, with (at worst) moderate increases to loads.

Study of the inclusive production of charged pions, kaons, and protons in pp collisions at $$\\sqrt{s} = 0.9, 2.76,\\mbox{ and }7~\\mbox{TeV}$$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.

Spectra of identified charged hadrons are measured in pp collisions at the LHC for sqrt(s) = 0.9, 2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and for rapidities abs(y) < 1 are identified via their energy loss in the CMS silicon tracker. The average pt increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully corrected pt spectra and integrated yields are compared to various tunes of the PYTHIA6 and PYTHIA8 event generators.

Experimental study of the novel tuned mass damper with inerter which enables changes of inertance

NASA Astrophysics Data System (ADS)

Brzeski, P.; Lazarek, M.; Perlikowski, P.

2017-09-01

In this paper we present the experimental verification of the novel tuned mass damper which enables changes of inertance. Characteristic feature of the proposed device is the presence of special type of inerter. This inerter incorporates a continuously variable transmission that enables stepless changes of inertance. Thus, it enables to adjust the parameters of the damping device to the current forcing characteristic. In the paper we present and describe the experimental rig that consists of the massive main oscillator forced kinematically and the prototype of the investigated damper. We perform a series of dedicated experiments to characterize the device and asses its damping efficiency. Moreover, we perform numerical simulations using the simple mathematical model of investigated system. Comparing the numerical results and the experimental data we legitimize the model and demonstrate the capabilities of the investigated tuned mass damper. Presented results prove that the concept of the novel type of tuned mass damper can be realized and enable to confirm its main advantages. Investigated prototype device offers excellent damping efficiency in a wide range of forcing frequencies.

Design of multi-wavelength tunable filter based on Lithium Niobate

NASA Astrophysics Data System (ADS)

Zhang, Ailing; Yao, Yuan; Zhang, Yue; Song, Hongyun

2018-05-01

A multi-wavelength tunable filter is designed. It consists of multiple waveguides among multiple waveguide gratings. A pair of electrodes were placed on both sides of each waveguide. The tunable filter uses the electro-optic effect of Lithium Niobate to tune the phase caused by each waveguide. Consequently, the wavelength and wavelength spacing of the filter are tuned by changing external voltages added on the electrode pairs. The tunable property of the filter is analyzed by phase matching condition and transfer-matrix method. Numerical results show that not only multiple wavelengths with narrow bandwidth are tuned with nearly equal spacing by synchronously changing the voltages added on all electrode pairs, but also the number of wavelengths is determined by the number of phase shifts caused by electrode pairs. Furthermore, due to the electro-optic effect of Lithium Niobate, the tuning speed of the filter can reach the order of ns.

Dynamical tuning for MPC using population games: A water supply network application.

PubMed

Barreiro-Gomez, Julian; Ocampo-Martinez, Carlos; Quijano, Nicanor

2017-07-01

Model predictive control (MPC) is a suitable strategy for the control of large-scale systems that have multiple design requirements, e.g., multiple physical and operational constraints. Besides, an MPC controller is able to deal with multiple control objectives considering them within the cost function, which implies to determine a proper prioritization for each of the objectives. Furthermore, when the system has time-varying parameters and/or disturbances, the appropriate prioritization might vary along the time as well. This situation leads to the need of a dynamical tuning methodology. This paper addresses the dynamical tuning issue by using evolutionary game theory. The advantages of the proposed method are highlighted and tested over a large-scale water supply network with periodic time-varying disturbances. Finally, results are analyzed with respect to a multi-objective MPC controller that uses static tuning. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Tuning supersymmetric models at the LHC: a comparative analysis at two-loop level.

NASA Astrophysics Data System (ADS)

Ghilencea, D. M.; Lee, H. M.; Park, M.

2012-07-01

We provide a comparative study of the fine tuning amount (Δ) at the two-loop leading log level in supersymmetric models commonly used in SUSY searches at the LHC. These are the constrained MSSM (CMSSM), non-universal Higgs masses models (NUHM1, NUHM2), non-universal gaugino masses model (NUGM) and GUT related gaugino masses models (NUGMd). Two definitions of the fine tuning are used, the first (Δmax) measures maximal fine-tuning w.r.t. individual parameters while the second (Δ q ) adds their contribution in "quadrature". As a direct consequence of two theoretical constraints (the EW minimum conditions), fine tuning (Δ q ) emerges at the mathematical level as a suppressing factor (effective prior) of the averaged likelihood ( L ) under the priors, under the integral of the global probability of measuring the data (Bayesian evidence p( D)). For each model, there is little difference between Δ q , Δmax in the region allowed by the data, with similar behaviour as functions of the Higgs, gluino, stop mass or SUSY scale ( {m_{{SUSY}}} = {( {{m_{{overline t 1}}}{m_{{overline t 2}}}} )^{{{{1} / {2} .}}}} ) or dark matter and g - 2 constraints. The analysis has the advantage that by replacing any of these mass scales or constraints by their latest bounds one easily infers for each model the value of Δ q , Δmax or vice versa. For all models, minimal fine tuning is achieved for M higgs near 115 GeV with a Δ q ≈ Δmax ≈ 10 to 100 depending on the model, and in the CMSSM this is actually a global minimum. Due to a strong (≈ exponential) dependence of Δ on M higgs, for a Higgs mass near 125 GeV, the above values of Δ q ≈ Δmax increase to between 500 and 1000. Possible corrections to these values are briefly discussed.

Spin Testing for Durability Began on a Self-Tuning Impact Damper for Turbomachinery Blades

NASA Technical Reports Server (NTRS)

Duffy, Kirsten; Mehmed, Oral

2003-01-01

NASA and Pratt & Whitney will collaborate under a Space Act Agreement to perform spin testing of the impact damper to verify damping effectiveness and durability. Pratt & Whitney will provide the turbine blade and damper hardware for the tests. NASA will provide the facility and perform the tests. Effectiveness and durability will be investigated during and after sustained sweeps of rotor speed through resonance. Tests of a platform wedge damper are also planned to compare its effectiveness with that of the impact damper. Results from baseline tests without dampers will be used to measure damping effectiveness. The self-tuning impact damper combines two damping methods-the tuned mass damper and the impact damper. It consists of a ball located within a cavity in the blade. This ball rolls back and forth on a spherical trough under centrifugal load (tuned mass damper) and can strike the walls of the cavity (impact damper). The ball s rolling natural frequency is proportional to the rotor speed and can be designed to follow an engine-order line (integer multiple of rotor speed). Aerodynamic forcing frequencies typically follow these engineorder lines, and a damper tuned to the engine order will most effectively reduce blade vibrations when the resonant frequency equals the engine-order forcing frequency. This damper has been tested in flat plates and turbine blades in the Dynamic Spin Facility. During testing, a pair of plates or blades rotates in vacuum. Excitation is provided by one of three methods--eddy-current engine-order excitation (ECE), electromechanical shakers, and magnetic bearing excitation. The eddy-current system consists of magnets located circumferentially around the rotor. As a blade passes a magnet, a force is imparted on the blade. The number of magnets used can be varied to change the desired engine order of the excitation. The magnets are remotely raised or lowered to change the magnitude of the force on the blades. The other two methods apply force to the rotating shaft itself at frequencies independent of the rotor speed. During testing, blade vibration is monitored with strain gauges and laser displacement probes.

Natural SM-like 126 GeV Higgs boson via nondecoupling D terms

DOE PAGES

Bertuzzo, Enrico; Frugiuele, Claudia

2016-02-16

Accommodating both a 126 GeV mass and standard model (SM)-like couplings for the Higgs has a fine-tuning price in supersymmetric models. Examples are the minimal supersymmetric standard model, in which SM-like couplings are natural, but raising the Higgs mass to 126 GeV requires a considerable tuning, and the nonminimal supersymmetric standard model, in which the situation is reversed: the Higgs is naturally heavier, but being SM-like requires some tuning. Finally, we show that models with nondecoupling D terms alleviate this tension—a 126 GeV SM-like Higgs comes out basically with no fine-tuning cost. In addition, the analysis of the fine-tuning of the extended gaugemore » sector shows that naturalness requires the heavy gauge bosons to likely be within the reach of LHC run II.« less

Lightweight linear alternators with and without capacitive tuning

NASA Astrophysics Data System (ADS)

Niedra, Janis M.

1993-06-01

Permanent magnet excited linear alternators rated tens of kW and coupled to free-piston Stirling engines are presently viewed as promising candidates for long term generation of electric power in both space and terrestrial applications. Series capacitive cancellation of the internal inductive reactance of such alternators was considered a viable way to both increase power extraction and to suppress unstable modes of the thermodynamic oscillation. Idealized toroidal and cylindrical alternator geometries are used for a comparative study of the issues of specific mass and capacitive tuning, subject to stability criteria. The analysis shows that the stator mass of an alternator designed to be capacitively tuned is always greater than the minimum achievable stator mass of an alternator designed with no capacitors, assuming equal utilization of materials ratings and the same frequency and power to a resistive load. This conclusion is not substantially altered when the usually lesser masses of the magnets and of any capacitors are added. Within the reported stability requirements and under circumstances of normal materials ratings, this study finds no clear advantage to capacitive tuning. Comparative plots of the various constituent masses are presented versus the internal power factor taken as a design degree of freedom. The explicit formulas developed for stator core, coil, capacitor, and magnet masses and for the degree of magnet utilization provide useful estimates of scaling effects.

Lightweight linear alternators with and without capacitive tuning

NASA Technical Reports Server (NTRS)

Niedra, Janis M.

1993-01-01

Permanent magnet excited linear alternators rated tens of kW and coupled to free-piston Stirling engines are presently viewed as promising candidates for long term generation of electric power in both space and terrestrial applications. Series capacitive cancellation of the internal inductive reactance of such alternators was considered a viable way to both increase power extraction and to suppress unstable modes of the thermodynamic oscillation. Idealized toroidal and cylindrical alternator geometries are used for a comparative study of the issues of specific mass and capacitive tuning, subject to stability criteria. The analysis shows that the stator mass of an alternator designed to be capacitively tuned is always greater than the minimum achievable stator mass of an alternator designed with no capacitors, assuming equal utilization of materials ratings and the same frequency and power to a resistive load. This conclusion is not substantially altered when the usually lesser masses of the magnets and of any capacitors are added. Within the reported stability requirements and under circumstances of normal materials ratings, this study finds no clear advantage to capacitive tuning. Comparative plots of the various constituent masses are presented versus the internal power factor taken as a design degree of freedom. The explicit formulas developed for stator core, coil, capacitor, and magnet masses and for the degree of magnet utilization provide useful estimates of scaling effects.

Dipole moment and polarizability of impurity doped quantum dots under anisotropy, spatially-varying effective mass and dielectric screening function: Interplay with noise

NASA Astrophysics Data System (ADS)

Ghosh, Anuja; Ghosh, Manas

2018-01-01

Present work explores the profiles of polarizability (αp) and electric dipole moment (μ) of impurity doped GaAs quantum dot (QD) under the aegis of spatially-varying effective mass, spatially-varying dielectric constant and anisotropy of the system. Presence of noise has also been invoked to examine how its intervention further tunes αp and μ. Noise term maintains a Gaussian white feature and it has been incorporated to the system through two different roadways; additive and multiplicative. The various facets of influence of spatially-varying effective mass, spatially-varying dielectric constant and anisotropy on αp and μ depend quite delicately on presence/absence of noise and also on the mode through which noise has been administered. The outcomes of the study manifest viable routes to harness the dipole moment and polarizability of doped QD system through the interplay between noise, anisotropy and variable effective mass and dielectric constant of the system.

Vibration reduction in a tilting rotor using centrifugal pendulum vibration absorbers

NASA Astrophysics Data System (ADS)

Shi, Chengzhi; Shaw, Steven W.; Parker, Robert G.

2016-12-01

This paper investigates vibration reduction in a rigid rotor with tilting, rotational, and translational motions using centrifugal pendulum vibration absorbers (CPVAs). A linearized vibration model is derived for the system consisting of the rotor and multiple sets of absorbers tuned to different orders. Each group of absorbers lies in a given plane perpendicular to the rotor rotation axis. Gyroscopic system modal analysis is applied to derive the steady-state response of the absorbers and the rotor to external, rotor-order, periodic forces and torques with frequency mΩ, where Ω is the mean rotor speed and m is the engine order (rotor-order). It is found that an absorber group with tuning order m is effective at reducing the rotor translational, tilting, and rotational vibrations, provided certain conditions are met. When the periodic force and torque are caused by N substructures that are equally spaced around the rotor, the rotor translational and tilting vibrations at order j are addressed by two absorber groups with tuning orders jN±1. In this case, the rotor rotational vibration at order j can be attenuated by an absorber group with tuning order jN. The results show how the response depends on the load amplitudes and order, the rotor speed, and design parameters associated with the sets of absorbers, most importantly, their tuning, mass, and plane of placement. In the ideal case with zero damping and exact tuning of the absorber sets, the vibrations can be eliminated for a range of loads over which the linearized model holds. The response for systems with detuned absorbers is also determined, which is relevant to applications where small detuning is employed due to robustness issues, and to allow for a larger range of operating loads over which the absorbers are effective. The system also exhibits undesirable resonances very close to these tuning conditions, an issue that is difficult to resolve and deserves further investigation.

Dirac gauginos, R symmetry and the 125 GeV Higgs

DOE PAGES

Bertuzzo, Enrico; Frugiuele, Claudia; Gregoire, Thomas; ...

2015-04-20

We study a supersymmetric scenario with a quasi exact R-symmetry in light of the discovery of a Higgs resonance with a mass of 125 GeV. In such a framework, the additional adjoint superfields, needed to give Dirac masses to the gauginos, contribute both to the Higgs mass and to electroweak precision observables. We then analyze the interplay between the two aspects, finding regions in parameter space in which the contributions to the precision observables are under control and a 125 GeV Higgs boson can be accommodated. Furthermore, we estimate the fine-tuning of the model finding regions of the parameter spacemore » still unexplored by the LHC with a fine-tuning considerably improved with respect to the minimal supersymmetric scenario. In particular, sizable non-holomorphic (non-supersoft) adjoints masses are required to reduce the fine-tuning.« less

Full-lifetime simulations of multiple planets across all phases of stellar evolution

NASA Astrophysics Data System (ADS)

Veras, D.; Mustill, A. J.; Gänsicke, B. T.; Redfield, S.; Georgakarakos, N.; Bowler, A. B.; Lloyd, M. J. S.

2017-09-01

We know that planetary systems are just as common around white dwarfs as around main-sequence stars. However, self-consistently linking a planetary system across these two phases of stellar evolution through the violent giant branch poses computational challenges, and previous studies restricted architectures to equal-mass planets. Here, we remove this constraint and perform over 450 numerical integrations over a Hubble time (14 Gyr) of packed planetary systems with unequal-mass planets. We characterize the resulting trends as a function of planet order and mass. We find that intrusive radial incursions in the vicinity of the white dwarf become less likely as the dispersion amongst planet masses increases. The orbital meandering which may sustain a sufficiently dynamic environment around a white dwarf to explain observations is more dependent on the presence of terrestrial-mass planets than any variation in planetary mass. Triggering unpacking or instability during the white dwarf phase is comparably easy for systems of unequal-mass planets and systems of equal-mass planets; instabilities during the giant branch phase remain rare and require fine-tuning of initial conditions. We list the key dynamical features of each simulation individually as a potential guide for upcoming discoveries.

Supersymmetric D-term Twin Higgs

DOE PAGES

Badziak, Marcin; Harigaya, Keisuke

2017-06-01

Here, we propose a new type of supersymmetric Twin Higgs model where the SU(4) invariant quartic term is provided by a D-term potential of a new U(1) gauge symmetry. In the model the 125 GeV Higgs mass can be obtained for stop masses below 1 TeV, and a tuning required to obtain the correct electroweak scale can be as low as 20%. Finally, a stop mass of about 2 TeV is also possible with tuning of order O(10)% .

Aircraft interior noise reduction by alternate resonance tuning

NASA Technical Reports Server (NTRS)

Gottwald, James A.; Bliss, Donald B.

1990-01-01

The focus is on a noise control method which considers aircraft fuselages lined with panels alternately tuned to frequencies above and below the frequency that must be attenuated. An interior noise reduction called alternate resonance tuning (ART) is described both theoretically and experimentally. Problems dealing with tuning single paneled wall structures for optimum noise reduction using the ART methodology are presented, and three theoretical problems are analyzed. The first analysis is a three dimensional, full acoustic solution for tuning a panel wall composed of repeating sections with four different panel tunings within that section, where the panels are modeled as idealized spring-mass-damper systems. The second analysis is a two dimensional, full acoustic solution for a panel geometry influenced by the effect of a propagating external pressure field such as that which might be associated with propeller passage by a fuselage. To reduce the analysis complexity, idealized spring-mass-damper panels are again employed. The final theoretical analysis presents the general four panel problem with real panel sections, where the effect of higher structural modes is discussed. Results from an experimental program highlight real applications of the ART concept and show the effectiveness of the tuning on real structures.

Multiplicative and additive modulation of neuronal tuning with population activity affects encoded information

PubMed Central

Arandia-Romero, Iñigo; Tanabe, Seiji; Drugowitsch, Jan; Kohn, Adam; Moreno-Bote, Rubén

2016-01-01

Numerous studies have shown that neuronal responses are modulated by stimulus properties, and also by the state of the local network. However, little is known about how activity fluctuations of neuronal populations modulate the sensory tuning of cells and affect their encoded information. We found that fluctuations in ongoing and stimulus-evoked population activity in primate visual cortex modulate the tuning of neurons in a multiplicative and additive manner. While distributed on a continuum, neurons with stronger multiplicative effects tended to have less additive modulation, and vice versa. The information encoded by multiplicatively-modulated neurons increased with greater population activity, while that of additively-modulated neurons decreased. These effects offset each other, so that population activity had little effect on total information. Our results thus suggest that intrinsic activity fluctuations may act as a `traffic light' that determines which subset of neurons are most informative. PMID:26924437

High-Level Psychophysical Tuning Curves: Forward Masking in Normal-Hearing and Hearing-Impaired Listeners.

ERIC Educational Resources Information Center

Nelson, David A.

1991-01-01

Forward-masked psychophysical tuning curves were obtained at multiple probe levels from 26 normal-hearing listeners and 24 ears of 21 hearing-impaired listeners with cochlear hearing loss. Results indicated that some cochlear hearing losses influence the sharp tuning capabilities usually associated with outer hair cell function. (Author/JDD)

Comprehensive Optimization of LC-MS Metabolomics Methods Using Design of Experiments (COLMeD).

PubMed

Rhoades, Seth D; Weljie, Aalim M

2016-12-01

Both reverse-phase and HILIC chemistries are deployed for liquid-chromatography mass spectrometry (LC-MS) metabolomics analyses, however HILIC methods lag behind reverse-phase methods in reproducibility and versatility. Comprehensive metabolomics analysis is additionally complicated by the physiochemical diversity of metabolites and array of tunable analytical parameters. Our aim was to rationally and efficiently design complementary HILIC-based polar metabolomics methods on multiple instruments using Design of Experiments (DoE). We iteratively tuned LC and MS conditions on ion-switching triple quadrupole (QqQ) and quadrupole-time-of-flight (qTOF) mass spectrometers through multiple rounds of a workflow we term COLMeD (Comprehensive optimization of LC-MS metabolomics methods using design of experiments). Multivariate statistical analysis guided our decision process in the method optimizations. LC-MS/MS tuning for the QqQ method on serum metabolites yielded a median response increase of 161.5% (p<0.0001) over initial conditions with a 13.3% increase in metabolite coverage. The COLMeD output was benchmarked against two widely used polar metabolomics methods, demonstrating total ion current increases of 105.8% and 57.3%, with median metabolite response increases of 106.1% and 10.3% (p<0.0001 and p<0.05 respectively). For our optimized qTOF method, 22 solvent systems were compared on a standard mix of physiochemically diverse metabolites, followed by COLMeD optimization, yielding a median 29.8% response increase (p<0.0001) over initial conditions. The COLMeD process elucidated response tradeoffs, facilitating improved chromatography and MS response without compromising separation of isobars. COLMeD is efficient, requiring no more than 20 injections in a given DoE round, and flexible, capable of class-specific optimization as demonstrated through acylcarnitine optimization within the QqQ method.

Comprehensive Optimization of LC-MS Metabolomics Methods Using Design of Experiments (COLMeD)

PubMed Central

Rhoades, Seth D.

2017-01-01

Introduction Both reverse-phase and HILIC chemistries are deployed for liquid-chromatography mass spectrometry (LC-MS) metabolomics analyses, however HILIC methods lag behind reverse-phase methods in reproducibility and versatility. Comprehensive metabolomics analysis is additionally complicated by the physiochemical diversity of metabolites and array of tunable analytical parameters. Objective Our aim was to rationally and efficiently design complementary HILIC-based polar metabolomics methods on multiple instruments using Design of Experiments (DoE). Methods We iteratively tuned LC and MS conditions on ion-switching triple quadrupole (QqQ) and quadrupole-time-of-flight (qTOF) mass spectrometers through multiple rounds of a workflow we term COLMeD (Comprehensive optimization of LC-MS metabolomics methods using design of experiments). Multivariate statistical analysis guided our decision process in the method optimizations. Results LC-MS/MS tuning for the QqQ method on serum metabolites yielded a median response increase of 161.5% (p<0.0001) over initial conditions with a 13.3% increase in metabolite coverage. The COLMeD output was benchmarked against two widely used polar metabolomics methods, demonstrating total ion current increases of 105.8% and 57.3%, with median metabolite response increases of 106.1% and 10.3% (p<0.0001 and p<0.05 respectively). For our optimized qTOF method, 22 solvent systems were compared on a standard mix of physiochemically diverse metabolites, followed by COLMeD optimization, yielding a median 29.8% response increase (p<0.0001) over initial conditions. Conclusions The COLMeD process elucidated response tradeoffs, facilitating improved chromatography and MS response without compromising separation of isobars. COLMeD is efficient, requiring no more than 20 injections in a given DoE round, and flexible, capable of class-specific optimization as demonstrated through acylcarnitine optimization within the QqQ method. PMID:28348510

Testing a simple control law to reduce broadband frequency harmonic vibrations using semi-active tuned mass dampers

NASA Astrophysics Data System (ADS)

Moutinho, Carlos

2015-05-01

This paper is focused on the control problems related to semi-active tuned mass dampers (TMDs) used to reduce harmonic vibrations, specially involving civil structures. A simplified version of the phase control law is derived and its effectiveness is investigated and evaluated. The objective is to improve the functioning of control systems of this type by simplifying the measurement process and reducing the number of variables involved, making the control system more feasible and reliable. Because the control law is of ON/OFF type, combined with appropriate trigger conditions, the activity of the actuation system may be significantly reduced, which may be of few seconds a day in many practical cases, increasing the durability of the device and reducing its maintenance. Moreover, due to the ability of the control system to command the motion of the inertial mass, the semi-active TMD is relatively insensitive to its initial tuning, resulting in the capability of self-tuning and in the possibility of controlling several vibration modes of a structure over a significant broadband frequency.

Fine-tuning the onset of myogenesis by homeobox proteins that interact with the Myf5 limb enhancer

PubMed Central

Daubas, Philippe; Duval, Nathalie; Bajard, Lola; Langa Vives, Francina; Robert, Benoît; Mankoo, Baljinder S.; Buckingham, Margaret

2015-01-01

ABSTRACT Skeletal myogenesis in vertebrates is initiated at different sites of skeletal muscle formation during development, by activation of specific control elements of the myogenic regulatory genes. In the mouse embryo, Myf5 is the first myogenic determination gene to be expressed and its spatiotemporal regulation requires multiple enhancer sequences, extending over 120 kb upstream of the Mrf4-Myf5 locus. An enhancer, located at −57/−58 kb from Myf5, is responsible for its activation in myogenic cells derived from the hypaxial domain of the somite, that will form limb muscles. Pax3 and Six1/4 transcription factors are essential activators of this enhancer, acting on a 145-bp core element. Myogenic progenitor cells that will form the future muscle masses of the limbs express the factors necessary for Myf5 activation when they delaminate from the hypaxial dermomyotome and migrate into the forelimb bud, however they do not activate Myf5 and the myogenic programme until they have populated the prospective muscle masses. We show that Msx1 and Meox2 homeodomain-containing transcription factors bind in vitro and in vivo to specific sites in the 145-bp element, and are implicated in fine-tuning activation of Myf5 in the forelimb. Msx1, when bound between Pax and Six sites, prevents the binding of these key activators, thus inhibiting transcription of Myf5 and consequent premature myogenic differentiation. Meox2 is required for Myf5 activation at the onset of myogenesis via direct binding to other homeodomain sites in this sequence. Thus, these homeodomain factors, acting in addition to Pax3 and Six1/4, fine-tune the entry of progenitor cells into myogenesis at early stages of forelimb development. PMID:26538636

Optimum design of a novel pounding tuned mass damper under harmonic excitation

NASA Astrophysics Data System (ADS)

Wang, Wenxi; Hua, Xugang; Wang, Xiuyong; Chen, Zhengqing; Song, Gangbing

2017-05-01

In this paper, a novel pounding tuned mass damper (PTMD) utilizing pounding damping is proposed to reduce structural vibration by increasing the damping ratio of a lightly damped structure. The pounding boundary covered by viscoelastic material is fixed right next to the tuned mass when the spring-mass system is in the equilibrium position. The dynamic properties of the proposed PTMD, including the natural frequency and the equivalent damping ratio, are derived theoretically. Moreover, the numerical simulation method by using an impact force model to study the PTMD is proposed and validated by pounding experiments. To minimize the maximum dynamic magnification factor under harmonic excitations, an optimum design of the PTMD is developed. Finally, the optimal PTMD is implemented to control a lightly damped frame structure. A comparison of experimental and simulated results reveals that the proposed impact force model can accurately model the pounding force. Furthermore, the proposed PTMD is effective to control the vibration in a wide frequency range, as demonstrated experimentally.

Frequency Response of an Aircraft Wing with Discrete Source Damage Using Equivalent Plate Analysis

NASA Technical Reports Server (NTRS)

Krishnamurthy, T.; Eldred, Lloyd B.

2007-01-01

An equivalent plate procedure is developed to provide a computationally efficient means of matching the stiffness and frequencies of flight vehicle wing structures for prescribed loading conditions. Several new approaches are proposed and studied to match the stiffness and first five natural frequencies of the two reference models with and without damage. One approach divides the candidate reference plate into multiple zones in which stiffness and mass can be varied using a variety of materials including aluminum, graphite-epoxy, and foam-core graphite-epoxy sandwiches. Another approach places point masses along the edge of the stiffness-matched plate to tune the natural frequencies. Both approaches are successful at matching the stiffness and natural frequencies of the reference plates and provide useful insight into determination of crucial features in equivalent plate models of aircraft wing structures.

Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Meng; Mao, Haiyang; Li, Zhigang

2015-07-15

This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequencymore » interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes.« less

Liquid Chromatography at Critical Conditions: Balancing size exclusion and adsorption in nanopores

NASA Astrophysics Data System (ADS)

Abdulahad, Asem; Amos, Jeffrey; Ryu, Chang

2009-03-01

Liquid chromatography at critical condition (LCCC) is a measure to identify thermodynamic conditions, in which polymers elute independently of molar mass during high performance liquid chromatography. Under these critical conditions the entropic exclusions that dominate size exclusion chromatography (SEC) and the enthalpic adsorption that governs adsorption-based interaction chromatography (IC) are said to negate one another resulting in simultaneous elution of the polymer of different molecular weights. Using multiple C18-bonded silica columns with different average nanopore sizes (from 5 nm to 30 nm), we will study the LCCC conditions of PS in methylene chloride/acetonitrile solvent mixture at different temperature. In addition, we will show that the separation of polystyrene can be fine tuned using a refined temperature gradient interaction chromatography (TGIC) that employs multiple columns of varying pore size in sequence.

Achieving increased bandwidth for 4 degree of freedom self-tuning energy harvester

NASA Astrophysics Data System (ADS)

Staaf, L. G. H.; Smith, A. D.; Köhler, E.; Lundgren, P.; Folkow, P. D.; Enoksson, P.

2018-04-01

The frequency response of a self-tuning energy harvester composed of two piezoelectric cantilevers connected by a middle beam with a sliding mass is investigated. Measurements show that incorporation of a free-sliding mass increases the bandwidth. Using an analytical model, the system is explained through close investigation of the resonance modes. Resonance mode behavior further suggests that, by breaking the symmetry of the system, even broader bandwidths are achievable.

Supernatural MSSM

NASA Astrophysics Data System (ADS)

Du, Guangle; Li, Tianjun; Nanopoulos, D. V.; Raza, Shabbar

2015-07-01

We point out that the electroweak fine-tuning problem in the supersymmetric standard models (SSMs) is mainly due to the high energy definition of the fine-tuning measure. We propose supernatural supersymmetry which has an order one high energy fine-tuning measure automatically. The key point is that all the mass parameters in the SSMs arise from a single supersymmetry breaking parameter. In this paper, we show that there is no supersymmetry electroweak fine-tuning problem explicitly in the minimal SSM (MSSM) with no-scale supergravity and Giudice-Masiero mechanism. We demonstrate that the Z -boson mass, the supersymmetric Higgs mixing parameter μ at the unification scale, and the sparticle spectrum can be given as functions of the universal gaugino mass M1 /2. Because the light stau is the lightest supersymmetric particle (LSP) in the no-scale MSSM, to preserve R parity, we introduce a non-thermally generated axino as the LSP dark matter candidate. We estimate the lifetime of the light stau by calculating its two-body and three-body decays to the LSP axino for several values of axion decay constant fa, and find that the light stau has a lifetime ττ ˜1 in [10-4,100 ] s for an fa range [109,1012] GeV . We show that our next to the LSP stau solutions are consistent with all the current experimental constraints, including the sparticle mass bounds, B-physics bounds, Higgs mass, cosmological bounds, and the bounds on long-lived charged particles at the LHC.

Effect of Weight on the Resonant Tuning of Energy Harvesting Devices Using Giant Magnetostrictive Materials.

PubMed

Mori, Kotaro; Horibe, Tadashi; Ishikawa, Shigekazu

2018-04-10

This study deals with the numerical and experimental study of the effect of weight on the resonant tuning and energy harvesting characteristics of energy harvesting devices using giant magnetostrictive materials. The energy harvesting device is made in a cantilever shape using a thin Terfenol-D layer, stainless steel (SUS) layer and a movable proof mass, among other things. In this study, two types of movable proof mass were prepared, and the device was designed to adjust its own resonant frequency automatically to match external vibration frequency in real time. Three-dimensional finite element analysis (FEA) was performed, and the resonant frequency, tip displacement, and output voltage in the devices were predicted and measured, and the simulation and experiment results were compared. The effects of the weight of the proof mass on self-tuning ability and time-varying behavior were then considered in particular.

Partially natural two Higgs doublet models

DOE PAGES

Draper, Patrick; Haber, Howard E.; Ruderman, Joshua T.

2016-06-21

It is possible that the electroweak scale is low due to the fine-tuning of microscopic parameters, which can result from selection effects. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would seem to disfavor this possibility, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. We discuss counterexamples where the Higgs boson is light because of fine-tuning, and a second scalar doublet is light because a discrete symmetry relates its mass to the mass of the Standard Model Higgs boson. Our examples require new vectorlike fermions atmore » the electroweak scale, and the models possess a rich electroweak vacuum structure. Furthermore, the mechanism that we discuss does not protect a small CP-odd Higgs mass in split or high-scale supersymmetry-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.« less

Development of multiclass methods for drug residues in eggs: hydrophilic solid-phase extraction cleanup and liquid chromatography/tandem mass spectrometry analysis of tetracycline, fluoroquinolone, sulfonamide, and beta-lactam residues.

PubMed

Heller, David N; Nochetto, Cristina B; Rummel, Nathan G; Thomas, Michael H

2006-07-26

A method was developed for detection of a variety of polar drug residues in eggs via liquid chromatography/tandem mass spectrometry (LC/MS/MS) with electrospray ionization (ESI). A total of twenty-nine target analytes from four drug classes-sulfonamides, tetracyclines, fluoroquinolones, and beta-lactams-were extracted from eggs using a hydrophilic-lipophilic balance polymer solid-phase extraction (SPE) cartridge. The extraction technique was developed for use at a target concentration of 100 ng/mL (ppb), and it was applied to eggs containing incurred residues from dosed laying hens. The ESI source was tuned using a single, generic set of tuning parameters, and analytes were separated with a phenyl-bonded silica cartridge column using an LC gradient. In a related study, residues of beta-lactam drugs were not found by LC/MS/MS in eggs from hens dosed orally with beta-lactam drugs. LC/MS/MS performance was evaluated on two generations of ion trap mass spectrometers, and key operational parameters were identified for each instrument. The ion trap acquisition methods could be set up for screening (a single product ion) or confirmation (multiple product ions). The lower limit of detection for screening purposes was 10-50 ppb (sulfonamides), 10-20 ppb (fluoroquinolones), and 10-50 ppb (tetracyclines), depending on the drug, instrument, and acquisition method. Development of this method demonstrates the feasibility of generic SPE, LC, and MS conditions for multiclass LC/MS residue screening.

Vibration properties of a rotating piezoelectric energy harvesting device that experiences gyroscopic effects

NASA Astrophysics Data System (ADS)

Lu, Haohui; Chai, Tan; Cooley, Christopher G.

2018-03-01

This study investigates the vibration of a rotating piezoelectric device that consists of a proof mass that is supported by elastic structures with piezoelectric layers. Vibration of the proof mass causes deformation in the piezoelectric structures and voltages to power the electrical loads. The coupled electromechanical equations of motion are derived using Newtonian mechanics and Kirchhoff's circuit laws. The free vibration behavior is investigated for devices with identical (tuned) and nonidentical (mistuned) piezoelectric support structures and electrical loads. These devices have complex-valued, speed-dependent eigenvalues and eigenvectors as a result of gyroscopic effects caused by their constant rotation. The characteristics of the complex-valued eigensolutions are related to physical behavior of the device's vibration. The free vibration behaviors differ significantly for tuned and mistuned devices. Due to gyroscopic effects, the proof mass in the tuned device vibrates in either forward or backward decaying circular orbits in single-mode free response. This is proven analytically for all tuned devices, regardless of the device's specific parameters or operating speed. For mistuned devices, the proof mass has decaying elliptical forward and backward orbits. The eigenvalues are shown to be sensitive to changes in the electrical load resistances. Closed-form solutions for the eigenvalues are derived for open and close circuits. At high rotation speeds these devices experience critical speeds and instability.

Lopsided gauge mediation

NASA Astrophysics Data System (ADS)

de Simone, Andrea; Franceschini, Roberto; Giudice, Gian Francesco; Pappadopulo, Duccio; Rattazzi, Riccardo

2011-05-01

It has been recently pointed out that the unavoidable tuning among supersymmetric parameters required to raise the Higgs boson mass beyond its experimental limit opens up new avenues for dealing with the so called μ- B μ problem of gauge mediation. In fact, it allows for accommodating, with no further parameter tuning, large values of B μ and of the other Higgs-sector soft masses, as predicted in models where both μ and B μ are generated at one-loop order. This class of models, called Lopsided Gauge Mediation, offers an interesting alternative to conventional gauge mediation and is characterized by a strikingly different phenomenology, with light higgsinos, very large Higgs pseudoscalar mass, and moderately light sleptons. We discuss general parametric relations involving the fine-tuning of the model and various observables such as the chargino mass and the value of tan β. We build an explicit model and we study the constraints coming from LEP and Tevatron. We show that in spite of new interactions between the Higgs and the messenger superfields, the theory can remain perturbative up to very large scales, thus retaining gauge coupling unification.

An equivalent method for optimization of particle tuned mass damper based on experimental parametric study

NASA Astrophysics Data System (ADS)

Lu, Zheng; Chen, Xiaoyi; Zhou, Ying

2018-04-01

A particle tuned mass damper (PTMD) is a creative combination of a widely used tuned mass damper (TMD) and an efficient particle damper (PD) in the vibration control area. The performance of a one-storey steel frame attached with a PTMD is investigated through free vibration and shaking table tests. The influence of some key parameters (filling ratio of particles, auxiliary mass ratio, and particle density) on the vibration control effects is investigated, and it is shown that the attenuation level significantly depends on the filling ratio of particles. According to the experimental parametric study, some guidelines for optimization of the PTMD that mainly consider the filling ratio are proposed. Furthermore, an approximate analytical solution based on the concept of an equivalent single-particle damper is proposed, and it shows satisfied agreement between the simulation and experimental results. This simplified method is then used for the preliminary optimal design of a PTMD system, and a case study of a PTMD system attached to a five-storey steel structure following this optimization process is presented.

A quenched study of the Schrödinger functional with chirally rotated boundary conditions: Applications

NASA Astrophysics Data System (ADS)

González López, J.; Jansen, K.; Renner, D. B.; Shindler, A.

2013-02-01

In a previous paper (González López, et al., 2013) [1], we have discussed the non-perturbative tuning of the chirally rotated Schrödinger functional (χSF). This tuning is required to eliminate bulk O(a) cutoff effects in physical correlation functions. Using our tuning results obtained in González López et al. (2013) [1] we perform scaling and universality tests analyzing the residual O(a) cutoff effects of several step-scaling functions and we compute renormalization factors at the matching scale. As an example of possible application of the χSF we compute the renormalized strange quark mass using large volume data obtained from Wilson twisted mass fermions at maximal twist.

Experimental and analytical study on vibration control effects of eddy-current tuned mass dampers under seismic excitations

NASA Astrophysics Data System (ADS)

Lu, Zheng; Huang, Biao; Zhang, Qi; Lu, Xilin

2018-05-01

Eddy-current tuned mass dampers (EC-TMDs) are non-contacting passive control devices and are developed on the basis of conventional tuned mass dampers. They comprise a solid mass, a stiffness element, and a damping element, wherein the damping mechanism originates from eddy currents. By relative motion between a non-magnetic conductive metal and a permanent magnet in a dynamic system, a time-varying magnetic field is induced in the conductor, thereby generating eddy currents. The eddy currents induce a magnetic field with opposite polarity, causing repulsive forces, i.e., damping forces. This technology can overcome the drawbacks of conventional tuned mass dampers, such as limited service life, deterioration of mechanical properties, and undesired additional stiffness. The experimental and analytical study of this system installed on a multi-degree-of-freedom structure is presented in this paper. A series of shaking table tests were conducted on a five-story steel-frame model with/without an EC-TMD to evaluate the effectiveness and performance of the EC-TMD in suppressing the vibration of the model under seismic excitations. The experimental results show that the EC-TMD can effectively reduce the displacement response, acceleration response, interstory drift ratio, and maximum strain of the columns under different earthquake excitations. Moreover, an analytical method was proposed on the basis of electromagnetic and structural dynamic theories. A comparison between the test and simulation results shows that the simulation method can be used to estimate the response of structures with an EC-TMD under earthquake excitations with acceptable accuracy.

The use of acoustically tuned resonators to improve the sound transmission loss of double panel partitions

NASA Astrophysics Data System (ADS)

Mason, J. M.; Fahy, F. J.

1986-10-01

The effectiveness of tuned Helmholtz resonators connected to the partition cavity in double-leaf partitions utilized in situations requiring low weight structures with high transmission loss is investigated as a method of improving sound transmission loss. This is demonstrated by a simple theoretical model and then experimentally verified. Results show that substantial improvements may be obtained at and around the mass-air-mass frequency for a total resonator volume 15 percent of the cavity volume.

A multiple degree of freedom electromechanical Helmholtz resonator.

PubMed

Liu, Fei; Horowitz, Stephen; Nishida, Toshikazu; Cattafesta, Louis; Sheplak, Mark

2007-07-01

The development of a tunable, multiple degree of freedom (MDOF) electromechanical Helmholtz resonator (EMHR) is presented. An EMHR consists of an orifice, backing cavity, and a compliant piezoelectric composite diaphragm. Electromechanical tuning of the acoustic impedance is achieved via passive electrical networks shunted across the piezoceramic. For resistive and capacitive loads, the EMHR is a 2DOF system possessing one acoustic and one mechanical DOF. When inductive ladder networks are employed, multiple electrical DOF are added. The dynamics of the multi-energy domain system are modeled using lumped elements and are represented in an equivalent electrical circuit, which is used to analyze the tunable acoustic input impedance of the EMHR. The two-microphone method is used to measure the acoustic impedance of two EMHR designs with a variety of resistive, capacitive, and inductive shunts. For the first design, the data demonstrate that the tuning range of the second resonant frequency for an EMHR with non-inductive shunts is limited by short- and open-circuit conditions, while an inductive shunt results in a 3DOF system possessing an enhanced tuning range. The second design achieves stronger coupling between the Helmholtz resonator and the piezoelectric backplate, and both resonant frequencies can be tuned with different non-inductive loads.

Aeroelastic Wing Shaping Control Subject to Actuation Constraints.

NASA Technical Reports Server (NTRS)

Swei, Sean Shan-Min; Nguyen, Nhan

2014-01-01

This paper considers the control of coupled aeroelastic aircraft model which is configured with Variable Camber Continuous Trailing Edge Flap (VCCTEF) system. The relative deflection between two adjacent flaps is constrained and this actuation constraint is accounted for when designing an effective control law for suppressing the wing vibration. A simple tuned-mass damper mechanism with two attached masses is used as an example to demonstrate the effectiveness of vibration suppression with confined motion of tuned masses. In this paper, a dynamic inversion based pseudo-control hedging (PCH) and bounded control approach is investigated, and for illustration, it is applied to the NASA Generic Transport Model (GTM) configured with VCCTEF system.

Representation of pitch chroma by multi-peak spectral tuning in human auditory cortex

PubMed Central

Moerel, Michelle; De Martino, Federico; Santoro, Roberta; Yacoub, Essa; Formisano, Elia

2015-01-01

Musical notes played at octave intervals (i.e., having the same pitch chroma) are perceived as similar. This well-known perceptual phenomenon lays at the foundation of melody recognition and music perception, yet its neural underpinnings remain largely unknown to date. Using fMRI with high sensitivity and spatial resolution, we examined the contribution of multi-peak spectral tuning to the neural representation of pitch chroma in human auditory cortex in two experiments. In experiment 1, our estimation of population spectral tuning curves from the responses to natural sounds confirmed—with new data—our recent results on the existence of cortical ensemble responses finely tuned to multiple frequencies at one octave distance (Moerel et al., 2013). In experiment 2, we fitted a mathematical model consisting of a pitch chroma and height component to explain the measured fMRI responses to piano notes. This analysis revealed that the octave-tuned populations—but not other cortical populations—harbored a neural representation of musical notes according to their pitch chroma. These results indicate that responses of auditory cortical populations selectively tuned to multiple frequencies at one octave distance predict well the perceptual similarity of musical notes with the same chroma, beyond the physical (frequency) distance of notes. PMID:25479020

Representation of pitch chroma by multi-peak spectral tuning in human auditory cortex.

PubMed

Moerel, Michelle; De Martino, Federico; Santoro, Roberta; Yacoub, Essa; Formisano, Elia

2015-02-01

Musical notes played at octave intervals (i.e., having the same pitch chroma) are perceived as similar. This well-known perceptual phenomenon lays at the foundation of melody recognition and music perception, yet its neural underpinnings remain largely unknown to date. Using fMRI with high sensitivity and spatial resolution, we examined the contribution of multi-peak spectral tuning to the neural representation of pitch chroma in human auditory cortex in two experiments. In experiment 1, our estimation of population spectral tuning curves from the responses to natural sounds confirmed--with new data--our recent results on the existence of cortical ensemble responses finely tuned to multiple frequencies at one octave distance (Moerel et al., 2013). In experiment 2, we fitted a mathematical model consisting of a pitch chroma and height component to explain the measured fMRI responses to piano notes. This analysis revealed that the octave-tuned populations-but not other cortical populations-harbored a neural representation of musical notes according to their pitch chroma. These results indicate that responses of auditory cortical populations selectively tuned to multiple frequencies at one octave distance predict well the perceptual similarity of musical notes with the same chroma, beyond the physical (frequency) distance of notes. Copyright © 2014 Elsevier Inc. All rights reserved.

Heisenberg Uncertainty and the Allowable Masses of the Up Quark and Down Quark

NASA Astrophysics Data System (ADS)

Orr, Brian

2004-05-01

A possible explanation for the inability to attain deterministic measurements of an elementary particle's energy, as given by the Heisenberg Uncertainty Principle, manifests itself in an interesting anthropic consequent of Andrei Linde's Self-reproducing Inflationary Multiverse model. In Linde's model, the physical laws and constants that govern our universe adopt other values in other universes, due to variable Higgs fields. While the physics in our universe allow for the advent of life and consciousness, the physics necessary for life are not likely to exist in other universes -- Linde demonstrates this through a kind of Darwinism for universes. Our universe, then, is unique. But what are the physical laws and constants that make our universe what it is? Craig Hogan identifies five physical constants that are not bound by symmetry. Fine-tuning these constants gives rise to the basic behavior and structures of the universe. Three of the non-symmetric constants are fermion masses: the up quark mass, the down quark mass, and the electron mass. I will explore Linde's and Hogan's works by comparing the amount of uncertainty in quark masses, as calculated from the Heisenberg Uncertainty Principle, to the range of quark mass values consistent with our observed universe. Should the fine-tuning of the up quark and down quark masses be greater than the range of Heisenberg uncertainties in their respective masses (as I predict, due to quantum tunneling), then perhaps there is a correlation between the measured Heisenberg uncertainty in quark masses and the fine-tuning of masses required for our universe to be as it is. Hogan; "Why the Universe is Just So;" Reviews of Modern Physics; Issue 4; Vol. 72; pg. 1149-1161; Oct. 2000 Linde, "The Self-Reproducing Inflationary Universe;" Scientific American; No. 5; Vol. 271; pg. 48-55; Nov. 1994

Phenomenology of NMSSM in TeV scale mirage mediation

NASA Astrophysics Data System (ADS)

Hagimoto, Kei; Kobayashi, Tatsuo; Makino, Hiroki; Okumura, Ken-ichi; Shimomura, Takashi

2016-02-01

We study the next-to-minimal supersymmetric standard model (NMSSM) with the TeV scale mirage mediation, which is known as a solution for the little hierarchy problem in supersymmetry. Our previous study showed that 125 GeV Higgs boson is realized with {O} (10)% fine-tuning for 1.5 TeV gluino (1 TeV stop) mass. The μ term could be as large as 500 GeV without sacrificing the fine-tuning thanks to a cancellation mechanism. The singlet-doublet mixing is suppressed by tan β. In this paper, we further extend this analysis. We argue that approximate scale symmetries play a role behind the suppression of the singlet-doublet mixing. They reduce the mixing matrix to a simple form that is useful to understand the results of the numerical analysis. We perform a comprehensive analysis of the fine-tuning including the singlet sector by introducing a simple formula for the fine-tuning measure. This shows that the singlet mass of the least fine-tuning is favored by the LEP anomaly for moderate tan β. We also discuss prospects for the precision measurements of the Higgs couplings at LHC and ILC and direct/indirect dark matter searches in the model.

Neurons in cat V1 show significant clustering by degree of tuning

PubMed Central

Ziskind, Avi J.; Emondi, Al A.; Kurgansky, Andrei V.; Rebrik, Sergei P.

2015-01-01

Neighboring neurons in cat primary visual cortex (V1) have similar preferred orientation, direction, and spatial frequency. How diverse is their degree of tuning for these properties? To address this, we used single-tetrode recordings to simultaneously isolate multiple cells at single recording sites and record their responses to flashed and drifting gratings of multiple orientations, spatial frequencies, and, for drifting gratings, directions. Orientation tuning width, spatial frequency tuning width, and direction selectivity index (DSI) all showed significant clustering: pairs of neurons recorded at a single site were significantly more similar in each of these properties than pairs of neurons from different recording sites. The strength of the clustering was generally modest. The percent decrease in the median difference between pairs from the same site, relative to pairs from different sites, was as follows: for different measures of orientation tuning width, 29–35% (drifting gratings) or 15–25% (flashed gratings); for DSI, 24%; and for spatial frequency tuning width measured in octaves, 8% (drifting gratings). The clusterings of all of these measures were much weaker than for preferred orientation (68% decrease) but comparable to that seen for preferred spatial frequency in response to drifting gratings (26%). For the above properties, little difference in clustering was seen between simple and complex cells. In studies of spatial frequency tuning to flashed gratings, strong clustering was seen among simple-cell pairs for tuning width (70% decrease) and preferred frequency (71% decrease), whereas no clustering was seen for simple-complex or complex-complex cell pairs. PMID:25652921

Optimal placement of tuning masses for vibration reduction in helicopter rotor blades

NASA Technical Reports Server (NTRS)

Pritchard, Jocelyn I.; Adelman, Howard M.

1988-01-01

Described are methods for reducing vibration in helicopter rotor blades by determining optimum sizes and locations of tuning masses through formal mathematical optimization techniques. An optimization procedure is developed which employs the tuning masses and corresponding locations as design variables which are systematically changed to achieve low values of shear without a large mass penalty. The finite-element structural analysis of the blade and the optimization formulation require development of discretized expressions for two performance parameters: modal shaping parameter and modal shear amplitude. Matrix expressions for both quantities and their sensitivity derivatives are developed. Three optimization strategies are developed and tested. The first is based on minimizing the modal shaping parameter which indirectly reduces the modal shear amplitudes corresponding to each harmonic of airload. The second strategy reduces these amplitudes directly, and the third strategy reduces the shear as a function of time during a revolution of the blade. The first strategy works well for reducing the shear for one mode responding to a single harmonic of the airload, but has been found in some cases to be ineffective for more than one mode. The second and third strategies give similar results and show excellent reduction of the shear with a low mass penalty.

Design and verification of wide-band, simultaneous, multi-frequency, tuning circuits for large moment transmitter loops

NASA Astrophysics Data System (ADS)

Dvorak, Steven L.; Sternberg, Ben K.; Feng, Wanjie

2017-03-01

In this paper we discuss the design and verification of wide-band, multi-frequency, tuning circuits for large-moment Transmitter (TX) loops. Since these multi-frequency, tuned-TX loops allow for the simultaneous transmission of multiple frequencies at high-current levels, they are ideally suited for frequency-domain geophysical systems that collect data while moving, such as helicopter mounted systems. Furthermore, since multi-frequency tuners use the same TX loop for all frequencies, instead of using separate tuned-TX loops for each frequency, they allow for the use of larger moment TX loops. In this paper we discuss the design and simulation of one- and three-frequency tuned TX loops and then present measurement results for a three-frequency, tuned-TX loop.

The use of acoustically tuned resonators to improve the sound transmission loss of double-panel partitions

NASA Astrophysics Data System (ADS)

Mason, J. M.; Fahy, F. J.

1988-07-01

Double-leaf partitions are often utilized in situations requiring low weight structures with high transmission loss, an example of current interest being the fuselage walls of propeller-driven aircraft. In this case, acoustic excitation is periodic and, if one of the frequencies of excitation lies in the region of the fundamental mass-air-mass frequency of the partition, insulation performance is considerably less than desired. The potential effectiveness of tuned Helmholtz resonators connected to the partition cavity is investigated as a method of improving transmission loss. This is demonstrated by a simple theoretical model and then experimentally verified. Results show that substantial improvements may be obtained at and around the mass-air-mass frequency for a total resonator volume 15 percent of the cavity volume.

Smart Novel Semi-Active Tuned Mass Damper for Fixed-Bottom and Floating Offshore Wind (Paper)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez Tsouroukdissian, Arturo; Lackner, Mathew; Cross-Whiter, John

The intention of this paper is to present the results of a novel smart semi-active tuned mass damper (SA-TMD), which mitigates unwanted loads for both fixed-bottom and floating offshore wind systems. The paper will focus on the most challenging water depths for both fixed-bottom and floating systems. A close to 38m Monopile and 55m Tension Leg Platform (TLP) will be considered. A technical development and trade-off analysis will be presented comparing the new system with existing passive non-linear TMD (N-TMD) technology and semi-active. TheSATMD works passively and activates itself with low power source under unwanted dynamic loading in less thanmore » 60msec. It is composed of both variable stiffness and damping elements coupled to a central pendulum mass. The analysis has been done numerically in both FAST(NREL) and Orcaflex (Orcina), and integrated in the Wind Turbine system employing CAD/CAE. The results of this work will pave the way for experimental testing to complete the technology qualification process. The load reductions under extreme and fatigue cases reach up significant levels at tower base, consequently reducing LCOE for fixed-bottom to floating wind solutions. The nacelle acceleration is reduced substantially under severe random wind and sea states, reducing the risks of failure of electromechanical components and blades at the rotor nacelle assembly. The SA-TMD system isa new technology that has not been applied previously in wind solutions. Structural damping devices aim to increase offshore wind turbine system robustness and reliability, which eases multiple substructures installations and global stability.« less

A Tuned Single Parameter for Representing Conjunction Risk

NASA Technical Reports Server (NTRS)

Plakaloic, D.; Hejduk, M. D.; Frigm, R. C.; Newman, L. K.

2011-01-01

Satellite conjunction assessment risk analysis is a subjective enterprise that can benefit from quantitative aids and, to this end, NASA/GSFC has developed a fuzzy logic construct - called the F-value - to attempt to provide a statement of conjunction risk that amalgamates multiple indices and yields a more stable intra-event assessment. This construct has now sustained an extended tuning procedure against heuristic analyst assessment of event risk. The tuning effort has resulted in modifications to the calculation procedure and the adjustment of tuning coefficients, producing a construct with both more predictive force and a better statement of its error.

Multiple adaptable mechanisms early in the primate visual pathway

PubMed Central

Dhruv, Neel T.; Tailby, Chris; Sokol, Sach H.; Lennie, Peter

2011-01-01

We describe experiments that isolate and characterize multiple adaptable mechanisms that influence responses of orientation-selective neurons in primary visual cortex (V1) of anesthetized macaque (Macaca fascicularis). The results suggest that three adaptable stages of machinery shape neural responses in V1: a broadly-tuned early stage and a spatio-temporally tuned later stage, both of which provide excitatory input, and a normalization pool that is also broadly tuned. The early stage and the normalization pool are revealed by adapting gratings that themselves fail to evoke a response from the neuron: either low temporal frequency gratings at the null orientation or gratings of any orientation drifting at high temporal frequencies. When effective, adapting stimuli that altered the sensitivity of these two mechanisms caused reductions of contrast gain and often brought about a paradoxical increase in response gain due to a relatively greater desensitization of the normalization pool. The tuned mechanism is desensitized only by stimuli well-matched to a neuron’s receptive field. We could thus infer desensitization of the tuned mechanism by comparing effects obtained with adapting gratings of preferred and null orientation modulated at low temporal frequencies. PMID:22016535

Tailoring Thermal Conductivity of Single-stranded Carbon-chain Polymers through Atomic Mass Modification

PubMed Central

Liao, Quanwen; Zeng, Lingping; Liu, Zhichun; Liu, Wei

2016-01-01

Tailoring the thermal conductivity of polymers is central to enlarge their applications in the thermal management of flexible integrated circuits. Progress has been made over the past decade by fabricating materials with various nanostructures, but a clear relationship between various functional groups and thermal properties of polymers remains to be established. Here, we numerically study the thermal conductivity of single-stranded carbon-chain polymers with multiple substituents of hydrogen atoms through atomic mass modification. We find that their thermal conductivity can be tuned by atomic mass modifications as revealed through molecular dynamics simulations. The simulation results suggest that heavy homogeneous substituents do not assist heat transport and trace amounts of heavy substituents can in fact hinder heat transport substantially. Our analysis indicates that carbon chain has the biggest contribution (over 80%) to the thermal conduction in single-stranded carbon-chain polymers. We further demonstrate that atomic mass modifications influence the phonon bands of bonding carbon atoms, and the discrepancies of phonon bands between carbon atoms are responsible for the remarkable drops in thermal conductivity and large thermal resistances in carbon chains. Our study provides fundamental insight into how to tailor the thermal conductivity of polymers through variable substituents. PMID:27713563

Spiral electrode d33 mode piezoelectric diaphragm combined with proof mass as energy harvester

NASA Astrophysics Data System (ADS)

Shen, Zhiyuan; Liu, Shuwei; Miao, Jianmin; Woh, Lye Sun; Wang, Zhihong

2015-03-01

The paper demonstrates an energy harvester using a freestanding piezoelectric diaphragm combined with a proof mass. The diaphragm bearing double-sided spiral electrodes makes use of the d33 piezoelectric effect to realize energy scavenging. The harvester was fabricated by using a MEMS technique. The energy converting performance of the diaphragm was characterized by a shaker system. Proof masses were combined at the center of the diaphragm to tune the resonance of the harvester for the sake of scavenging low frequency vibrational energy. A receptance model was built to explain the vibrational behavior of the combined system. The resonance tuning and energy harvesting performance of the combination system was experimentally verified.

Supersymmetry, naturalness, and signatures at the CERN LHC

NASA Astrophysics Data System (ADS)

Kitano, Ryuichiro; Nomura, Yasunori

2006-05-01

Weak scale supersymmetry is often said to be fine-tuned, especially if the matter content is minimal. This is not true if there is a large A term for the top squarks. We present a systematic study on fine-tuning in minimal supersymmetric theories and identify low-energy spectra that do not lead to severe fine-tuning. Characteristic features of these spectra are: a large A term for the top squarks, small top squark masses, moderately large tan⁡β, and a small μ parameter. There are classes of theories leading to these features, which are discussed. In one class, which allows a complete elimination of fine-tuning, the Higgsinos are the lightest among all the superpartners of the standard model particles, leading to three nearly degenerate neutralino/chargino states. This gives interesting signals at the LHC—the dilepton invariant mass distribution has a very small endpoint and shows a particular shape determined by the Higgsino nature of the two lightest neutralinos. We demonstrate that these signals are indeed useful in realistic analyses by performing Monte Carlo simulations, including detector simulations and background estimations. We also present a method that allows the determination of all the relevant superparticle masses without using input from particular models, despite the limited kinematical information due to short cascades. This allows us to test various possible models, which is demonstrated in the case of a model with mixed moduli-anomaly mediation. We also give a simple derivation of special renormalization group properties associated with moduli mediated supersymmetry-breaking, which are relevant in a model without fine-tuning.

Structures vibration control via Tuned Mass Dampers using a co-evolution Coral Reefs Optimization algorithm

NASA Astrophysics Data System (ADS)

Salcedo-Sanz, S.; Camacho-Gómez, C.; Magdaleno, A.; Pereira, E.; Lorenzana, A.

2017-04-01

In this paper we tackle a problem of optimal design and location of Tuned Mass Dampers (TMDs) for structures subjected to earthquake ground motions, using a novel meta-heuristic algorithm. Specifically, the Coral Reefs Optimization (CRO) with Substrate Layer (CRO-SL) is proposed as a competitive co-evolution algorithm with different exploration procedures within a single population of solutions. The proposed approach is able to solve the TMD design and location problem, by exploiting the combination of different types of searching mechanisms. This promotes a powerful evolutionary-like algorithm for optimization problems, which is shown to be very effective in this particular problem of TMDs tuning. The proposed algorithm's performance has been evaluated and compared with several reference algorithms in two building models with two and four floors, respectively.

Induction heating using induction coils in series-parallel circuits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsen, Marc Rollo; Geren, William Preston; Miller, Robert James

A part is inductively heated by multiple, self-regulating induction coil circuits having susceptors, coupled together in parallel and in series with an AC power supply. Each of the circuits includes a tuning capacitor that tunes the circuit to resonate at the frequency of AC power supply.

Integrated tuned vibration absorbers: a theoretical study.

PubMed

Gardonio, Paolo; Zilletti, Michele

2013-11-01

This article presents a simulation study on two integrated tuned vibration absorbers (TVAs) designed to control the global flexural vibration of lightly damped thin structures subject to broad frequency band disturbances. The first one consists of a single axial switching TVA composed by a seismic mass mounted on variable axial spring and damper elements so that the characteristic damping and natural frequency of the absorber can be switched iteratively to control the resonant response of three flexural modes of the hosting structure. The second one consists of a single three-axes TVA composed by a seismic mass mounted on axial and rotational springs and dampers, which are arranged in such a way that the suspended mass is characterized by uncoupled heave and pitch-rolling vibrations. In this case the three damping and natural frequency parameters of the absorber are tuned separately to control three flexural modes of the hosting structure. The simulation study shows that the proposed single-unit absorbers produce, respectively, 5.3 and 8.7 dB reductions of the global flexural vibration of a rectangular plate between 20 and 120 Hz.

Precision tests and fine tuning in twin Higgs models

NASA Astrophysics Data System (ADS)

Contino, Roberto; Greco, Davide; Mahbubani, Rakhi; Rattazzi, Riccardo; Torre, Riccardo

2017-11-01

We analyze the parametric structure of twin Higgs (TH) theories and assess the gain in fine tuning which they enable compared to extensions of the standard model with colored top partners. Estimates show that, at least in the simplest realizations of the TH idea, the separation between the mass of new colored particles and the electroweak scale is controlled by the coupling strength of the underlying UV theory, and that a parametric gain is achieved only for strongly-coupled dynamics. Motivated by this consideration we focus on one of these simple realizations, namely composite TH theories, and study how well such constructions can reproduce electroweak precision data. The most important effect of the twin states is found to be the infrared contribution to the Higgs quartic coupling, while direct corrections to electroweak observables are subleading and negligible. We perform a careful fit to the electroweak data including the leading-logarithmic corrections to the Higgs quartic up to three loops. Our analysis shows that agreement with electroweak precision tests can be achieved with only a moderate amount of tuning, in the range 5%-10%, in theories where colored states have mass of order 3-5 TeV and are thus out of reach of the LHC. For these levels of tuning, larger masses are excluded by a perturbativity bound, which makes these theories possibly discoverable, hence falsifiable, at a future 100 TeV collider.

Tm:germanate Fiber Laser: Tuning And Q-switching

NASA Technical Reports Server (NTRS)

Barnes, Norman P.; Walsh, Brian M.; Reichle, Donald J.; DeYoung, R. J.; Jiang, Shibin

2007-01-01

A Tm:germanate fiber laser produced >0.25 mJ/pulse in a 45 ns pulse. It is capable of producing multiple Q-switched pulses from a single p ump pulse. With the addition of a diffraction grating, Tm:germanate f iber lasers produced a wide, but length dependent, tuning range. By s electing the fiber length, the tuning range extends from 1.88 to 2.04 ?m. These traits make Tm:germanate lasers suitable for remote sensin g of water vapor.

Realizing up-conversion fluorescence tuning in lanthanide-doped nanocrystals by femtosecond pulse shaping method

PubMed Central

Zhang, Shian; Yao, Yunhua; Shuwu, Xu; Liu, Pei; Ding, Jingxin; Jia, Tianqing; Qiu, Jianrong; Sun, Zhenrong

2015-01-01

The ability to tune color output of nanomaterials is very important for their applications in laser, optoelectronic device, color display and multiplexed biolabeling. Here we first propose a femtosecond pulse shaping technique to realize the up-conversion fluorescence tuning in lanthanide-doped nanocrystals dispersed in the glass. The multiple subpulse formation by a square phase modulation can create different excitation pathways for various up-conversion fluorescence generations. By properly controlling these excitation pathways, the multicolor up-conversion fluorescence can be finely tuned. This color tuning by the femtosecond pulse shaping technique is realized in single material by single-color laser field, which is highly desirable for further applications of the lanthanide-doped nanocrystals. This femtosecond pulse shaping technique opens an opportunity to tune the color output in the lanthanide-doped nanocrystals, which may bring a new revolution in the control of luminescence properties of nanomaterials. PMID:26290391

Laser energy tuning of carrier effective mass and thermopower in epitaxial oxide thin films

NASA Astrophysics Data System (ADS)

Abutaha, A. I.; Sarath Kumar, S. R.; Alshareef, H. N.

2012-04-01

The effect of the laser fluence on high temperature thermoelectric properties of the La doped SrTiO3 (SLTO) thin films epitaxially grown on LaAlO3 <100> substrates by pulsed laser deposition is clarified. It is shown that oxygen vacancies that influence the effective mass of carriers in SLTO films can be tuned by varying the laser energy. The highest power factor of 0.433 W K-1 m-1 has been achieved at 636 K for a film deposited using the highest laser fluence of 7 J cm-2 pulse-1.

What Comes Beyond the Standard Models, Proceedings to the 9th Workshop held in Bled, Slovenia.

NASA Astrophysics Data System (ADS)

Mankoc Borstnik, Norma; Nielsen, Holger Bech; Froggatt, Colin D.; Lukman, Dragan

2006-12-01

Contents: 1. Child Universes in the Laboratory (S. Ansoldi and E.I. Guendelman) 2. Relation between Finestructure Constants at the Planck Scale from Multiple Point Principle (D.L. Bennett, L.V. Laperashvili and H.B. Nielsen) 3. On the Origin of Families of Fermions and Their Mass Matrices -- Approximate Analyses of Properties of Four Families Within Approach Unifying Spins and Charges (M. Breskvar, D. Lukman and N.S. Mankoc Borstnik) 4. Cosmoparticle Physics: Cross-disciplinary Study of Physics Beyond the Standard Model (M.Yu. Khlopov) 5. Discussion Section on 4th Generation (M.Yu. Khlopov) 6. Involution Requirement on a Boundary Makes Massless Fermions Compactified on a Finite Flat Disk Mass Protected (N.S. Mankoc Borstnik and H.B. Nielsen) 7. How Can Group Theory be Generalized so Perhaps Providing Further Information About Our Universe? (R. Mirman) 8. Future Dependent Initial Conditions from Imaginary Part in Lagrangian (H.B. Nielsen and M. Ninomiya) 9. Coupling Self-tuning to Critical Lines From Highly Compact Extra Dimensions (K. Petrov)

Blue Shifting Tuning of the Selective Reflection of Polymer Stabilized Cholesteric Liquid Crystals (Postprint)

DTIC Science & Technology

2017-08-08

deformation then affects the anchoring of the low-molar mass CLC mixture resulting in broadening of the reflection band due to nonuniformity in the pitch...confirmed that the tuning is a result of nonuniform pitch displacement across the cell gap.17 In this contribution, we report on the realization of yet

Tuning Parameters in Heuristics by Using Design of Experiments Methods

NASA Technical Reports Server (NTRS)

Arin, Arif; Rabadi, Ghaith; Unal, Resit

2010-01-01

With the growing complexity of today's large scale problems, it has become more difficult to find optimal solutions by using exact mathematical methods. The need to find near-optimal solutions in an acceptable time frame requires heuristic approaches. In many cases, however, most heuristics have several parameters that need to be "tuned" before they can reach good results. The problem then turns into "finding best parameter setting" for the heuristics to solve the problems efficiently and timely. One-Factor-At-a-Time (OFAT) approach for parameter tuning neglects the interactions between parameters. Design of Experiments (DOE) tools can be instead employed to tune the parameters more effectively. In this paper, we seek the best parameter setting for a Genetic Algorithm (GA) to solve the single machine total weighted tardiness problem in which n jobs must be scheduled on a single machine without preemption, and the objective is to minimize the total weighted tardiness. Benchmark instances for the problem are available in the literature. To fine tune the GA parameters in the most efficient way, we compare multiple DOE models including 2-level (2k ) full factorial design, orthogonal array design, central composite design, D-optimal design and signal-to-noise (SIN) ratios. In each DOE method, a mathematical model is created using regression analysis, and solved to obtain the best parameter setting. After verification runs using the tuned parameter setting, the preliminary results for optimal solutions of multiple instances were found efficiently.

The feasibility of manual parameter tuning for deformable breast MR image registration from a multi-objective optimization perspective.

PubMed

Pirpinia, Kleopatra; Bosman, Peter A N; Loo, Claudette E; Winter-Warnars, Gonneke; Janssen, Natasja N Y; Scholten, Astrid N; Sonke, Jan-Jakob; van Herk, Marcel; Alderliesten, Tanja

2017-06-23

Deformable image registration is typically formulated as an optimization problem involving a linearly weighted combination of terms that correspond to objectives of interest (e.g. similarity, deformation magnitude). The weights, along with multiple other parameters, need to be manually tuned for each application, a task currently addressed mainly via trial-and-error approaches. Such approaches can only be successful if there is a sensible interplay between parameters, objectives, and desired registration outcome. This, however, is not well established. To study this interplay, we use multi-objective optimization, where multiple solutions exist that represent the optimal trade-offs between the objectives, forming a so-called Pareto front. Here, we focus on weight tuning. To study the space a user has to navigate during manual weight tuning, we randomly sample multiple linear combinations. To understand how these combinations relate to desirability of registration outcome, we associate with each outcome a mean target registration error (TRE) based on expert-defined anatomical landmarks. Further, we employ a multi-objective evolutionary algorithm that optimizes the weight combinations, yielding a Pareto front of solutions, which can be directly navigated by the user. To study how the complexity of manual weight tuning changes depending on the registration problem, we consider an easy problem, prone-to-prone breast MR image registration, and a hard problem, prone-to-supine breast MR image registration. Lastly, we investigate how guidance information as an additional objective influences the prone-to-supine registration outcome. Results show that the interplay between weights, objectives, and registration outcome makes manual weight tuning feasible for the prone-to-prone problem, but very challenging for the harder prone-to-supine problem. Here, patient-specific, multi-objective weight optimization is needed, obtaining a mean TRE of 13.6 mm without guidance information reduced to 7.3 mm with guidance information, but also providing a Pareto front that exhibits an intuitively sensible interplay between weights, objectives, and registration outcome, allowing outcome selection.

The feasibility of manual parameter tuning for deformable breast MR image registration from a multi-objective optimization perspective

NASA Astrophysics Data System (ADS)

Pirpinia, Kleopatra; Bosman, Peter A. N.; E Loo, Claudette; Winter-Warnars, Gonneke; Y Janssen, Natasja N.; Scholten, Astrid N.; Sonke, Jan-Jakob; van Herk, Marcel; Alderliesten, Tanja

2017-07-01

Deformable image registration is typically formulated as an optimization problem involving a linearly weighted combination of terms that correspond to objectives of interest (e.g. similarity, deformation magnitude). The weights, along with multiple other parameters, need to be manually tuned for each application, a task currently addressed mainly via trial-and-error approaches. Such approaches can only be successful if there is a sensible interplay between parameters, objectives, and desired registration outcome. This, however, is not well established. To study this interplay, we use multi-objective optimization, where multiple solutions exist that represent the optimal trade-offs between the objectives, forming a so-called Pareto front. Here, we focus on weight tuning. To study the space a user has to navigate during manual weight tuning, we randomly sample multiple linear combinations. To understand how these combinations relate to desirability of registration outcome, we associate with each outcome a mean target registration error (TRE) based on expert-defined anatomical landmarks. Further, we employ a multi-objective evolutionary algorithm that optimizes the weight combinations, yielding a Pareto front of solutions, which can be directly navigated by the user. To study how the complexity of manual weight tuning changes depending on the registration problem, we consider an easy problem, prone-to-prone breast MR image registration, and a hard problem, prone-to-supine breast MR image registration. Lastly, we investigate how guidance information as an additional objective influences the prone-to-supine registration outcome. Results show that the interplay between weights, objectives, and registration outcome makes manual weight tuning feasible for the prone-to-prone problem, but very challenging for the harder prone-to-supine problem. Here, patient-specific, multi-objective weight optimization is needed, obtaining a mean TRE of 13.6 mm without guidance information reduced to 7.3 mm with guidance information, but also providing a Pareto front that exhibits an intuitively sensible interplay between weights, objectives, and registration outcome, allowing outcome selection.

Anthropic tuning of the weak scale and of m{sub u}/m{sub d} in two-Higgs-doublet models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barr, S. M.; Khan, Almas

2007-08-15

It is shown that, in a model in which up-type and down-type fermions acquire mass from different Higgs doublets, the anthropic tuning of the Higgs mass parameters can explain the fact that the observed masses of the d and u quarks are nearly the same with d slightly heavier. If Yukawa couplings are assumed not to scan (vary among domains), this would also help explain why t is much heavier than b. It is also pointed out that the existence of dark matter invalidates some earlier anthropic arguments against the viability of domains where the standard model Higgs has positivemore » {mu}{sup 2}, but makes other even stronger arguments possible.« less

Engine Tune-up Service. Unit 6: Emission Control Systems. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Morse, David T.; May, Theodore R.

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 6, Emission Control Systems, available separately as CE 031 220. Focus of the posttests is inspecting, testing, and servicing emission control systems. One multiple choice posttest is provided that covers the seven performance objectives contained in…

Engine Tune-Up Service. Unit 4: Secondary Circuit. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Morse, David T.

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 4, Secondary Circuit, available separately as CE 031 214. Focus of the posttests is testing and servicing the secondary ignition circuit. One multiple choice posttest is provided that covers the seven performance objectives contained in the unit. (No…

Engine Tune-Up Service. Unit 3: Primary Circuit. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Morse, David T.

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 3, Primary Circuit, available separately as CE 031 211. Focus of the posttests is setting the primary ignition circuit. One multiple choice posttest is provided, covering the eight performance objectives contained in the unit. (No answer key is…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baart, T. A.; Vandersypen, L. M. K.; Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft

We report the computer-automated tuning of gate-defined semiconductor double quantum dots in GaAs heterostructures. We benchmark the algorithm by creating three double quantum dots inside a linear array of four quantum dots. The algorithm sets the correct gate voltages for all the gates to tune the double quantum dots into the single-electron regime. The algorithm only requires (1) prior knowledge of the gate design and (2) the pinch-off value of the single gate T that is shared by all the quantum dots. This work significantly alleviates the user effort required to tune multiple quantum dot devices.

Adaptive tuned vibration absorber based on magnetorheological elastomer-shape memory alloy composite

NASA Astrophysics Data System (ADS)

Kumbhar, Samir B.; Chavan, S. P.; Gawade, S. S.

2018-02-01

Shape memory alloy (SMA) is an attractive smart material which could be used as stiffness tuning element in adaptive tuned vibration absorber (ATVA). The sharp modulus change in SMA material during phase transformation creates difficulties for smooth tuning to track forcing frequency to minimize vibrations of primary system. However, high hysteresis damping at low temperature martensitic phase degrades performance of vibration absorber. This paper deals with the study of dynamic response of system in which SMA and magnetorheological elastomer (MRE) are combined together to act as a smart spring- mass-damper system in a tuned vibration absorber. This composite is used as two way stiffness tuning element in ATVA for smooth and continuous tuning and to minimize the adverse effect at low temperature by increasing equivalent stiffness. The stiffnesses of SMA element and MRE are varied respectively by changing temperature and strength of external magnetic field. The two way stiffness tuning ability and adaptivity have been demonstrated analytically and experimentally. The experimental results show good agreement with analytical results. The proposed composite is able to shift the stiffness consequently the natural frequency of primary system as well as reduce the vibration level of primary system by substantial mount.

Recontextualizing YouTube: From Macro-Micro to Mass-Mediated Communicative Repertoires

ERIC Educational Resources Information Center

Rymes, Betsy

2012-01-01

In this article, I deconstruct the macro-micro dichotomy by arguing that the very same mass-media messages that appear culturally homogenizing (like catchy tunes and phrases) also invite creative recontextualizations (Bauman and Briggs 1990). Moreover, "the more widely circulated and mass-produced a message is, the more highly diverse the…

A Tale of Two Masses

ERIC Educational Resources Information Center

Bryan, Kurt

2011-01-01

This article presents an application of standard undergraduate ODE techniques to a modern engineering problem, that of using a tuned mass damper to control the vibration of a skyscraper. This material can be used in any ODE course in which the students have been familiarized with basic spring-mass models, resonance, and linear systems of ODEs.…

What hadron collider is required to discover or falsify natural supersymmetry?

NASA Astrophysics Data System (ADS)

Baer, Howard; Barger, Vernon; Gainer, James S.; Huang, Peisi; Savoy, Michael; Serce, Hasan; Tata, Xerxes

2017-11-01

Weak scale supersymmetry (SUSY) remains a compelling extension of the Standard Model because it stabilizes the quantum corrections to the Higgs and W , Z boson masses. In natural SUSY models these corrections are, by definition, never much larger than the corresponding masses. Natural SUSY models all have an upper limit on the gluino mass, too high to lead to observable signals even at the high luminosity LHC. However, in models with gaugino mass unification, the wino is sufficiently light that supersymmetry discovery is possible in other channels over the entire natural SUSY parameter space with no worse than 3% fine-tuning. Here, we examine the SUSY reach in more general models with and without gaugino mass unification (specifically, natural generalized mirage mediation), and show that the high energy LHC (HE-LHC), a pp collider with √{ s } = 33 TeV, will be able to detect the SUSY signal over the entire allowed mass range. Thus, HE-LHC would either discover or conclusively falsify natural SUSY with better than 3% fine-tuning using a conservative measure that allows for correlations among the model parameters.

Optimum tuned mass damper design using harmony search with comparison of classical methods

NASA Astrophysics Data System (ADS)

Nigdeli, Sinan Melih; Bekdaş, Gebrail; Sayin, Baris

2017-07-01

As known, tuned mass dampers (TMDs) are added to mechanical systems in order to obtain a good vibration damping. The main aim is to reduce the maximum amplitude at the resonance state. In this study, a metaheuristic algorithm called harmony search employed for the optimum design of TMDs. As the optimization objective, the transfer function of the acceleration of the system with respect to ground acceleration was minimized. The numerical trails were conducted for 4 single degree of freedom systems and the results were compared with classical methods. As a conclusion, the proposed method is feasible and more effective than the other documented methods.

Tuning the cosmological constant, broken scale invariance, unitarity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Förste, Stefan; Manz, Paul; Physikalisches Institut der Universität Bonn,Nussallee 12, 53115 Bonn

2016-06-10

We study gravity coupled to a cosmological constant and a scale but not conformally invariant sector. In Minkowski vacuum, scale invariance is spontaneously broken. We consider small fluctuations around the Minkowski vacuum. At the linearised level we find that the trace of metric perturbations receives a positive or negative mass squared contribution. However, only for the Fierz-Pauli combination the theory is free of ghosts. The mass term for the trace of metric perturbations can be cancelled by explicitly breaking scale invariance. This reintroduces fine-tuning. Models based on four form field strength show similarities with explicit scale symmetry breaking due tomore » quantisation conditions.« less

Measurement of the underlying event in the Drell–Yan process in proton–proton collisions at $$\\sqrt{s} = 7~\\mbox{TeV}$$

DOE PAGES

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; ...

2012-09-20

A measurement of the underlying event (UE) activity in proton-proton collisions at a center-of-mass energy of 7 TeV is performed using Drell--Yan events in a data sample corresponding to an integrated luminosity of 2.2 inverse femtobarns, collected by the CMS experiment at the LHC. The activity measured in the muonic final state (q q-bar to opposite-sign muons) is corrected to the particle level and compared with the predictions of various Monte Carlo generators and hadronization models. The dependence of the UE activity on the dimuon invariant mass is well described by PYTHIA and HERWIG++ tunes derived from the leading jet/trackmore » approach, illustrating the universality of the UE activity. The UE activity is observed to be independent of the dimuon invariant mass in the region above 40 GeV, while a slow increase is observed with increasing transverse momentum of the dimuon system. The dependence of the UE activity on the transverse momentum of the dimuon system is accurately described by MADGRAPH, which simulates multiple hard emissions.« less

Measurement of the underlying event in the Drell–Yan process in proton–proton collisions at $$\\sqrt{s} = 7~\\mbox{TeV}$$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.

A measurement of the underlying event (UE) activity in proton-proton collisions at a center-of-mass energy of 7 TeV is performed using Drell--Yan events in a data sample corresponding to an integrated luminosity of 2.2 inverse femtobarns, collected by the CMS experiment at the LHC. The activity measured in the muonic final state (q q-bar to opposite-sign muons) is corrected to the particle level and compared with the predictions of various Monte Carlo generators and hadronization models. The dependence of the UE activity on the dimuon invariant mass is well described by PYTHIA and HERWIG++ tunes derived from the leading jet/trackmore » approach, illustrating the universality of the UE activity. The UE activity is observed to be independent of the dimuon invariant mass in the region above 40 GeV, while a slow increase is observed with increasing transverse momentum of the dimuon system. The dependence of the UE activity on the transverse momentum of the dimuon system is accurately described by MADGRAPH, which simulates multiple hard emissions.« less

A New Approach to Identify Optimal Properties of Shunting Elements for Maximum Damping of Structural Vibration Using Piezoelectric Patches

NASA Technical Reports Server (NTRS)

Park, Junhong; Palumbo, Daniel L.

2004-01-01

The use of shunted piezoelectric patches in reducing vibration and sound radiation of structures has several advantages over passive viscoelastic elements, e.g., lower weight with increased controllability. The performance of the piezoelectric patches depends on the shunting electronics that are designed to dissipate vibration energy through a resistive element. In past efforts most of the proposed tuning methods were based on modal properties of the structure. In these cases, the tuning applies only to one mode of interest and maximum tuning is limited to invariant points when based on den Hartog's invariant points concept. In this study, a design method based on the wave propagation approach is proposed. Optimal tuning is investigated depending on the dynamic and geometric properties that include effects from boundary conditions and position of the shunted piezoelectric patch relative to the structure. Active filters are proposed as shunting electronics to implement the tuning criteria. The developed tuning methods resulted in superior capabilities in minimizing structural vibration and noise radiation compared to other tuning methods. The tuned circuits are relatively insensitive to changes in modal properties and boundary conditions, and can applied to frequency ranges in which multiple modes have effects.

An Adaptive Kalman Filter using a Simple Residual Tuning Method

NASA Technical Reports Server (NTRS)

Harman, Richard R.

1999-01-01

One difficulty in using Kalman filters in real world situations is the selection of the correct process noise, measurement noise, and initial state estimate and covariance. These parameters are commonly referred to as tuning parameters. Multiple methods have been developed to estimate these parameters. Most of those methods such as maximum likelihood, subspace, and observer Kalman Identification require extensive offline processing and are not suitable for real time processing. One technique, which is suitable for real time processing, is the residual tuning method. Any mismodeling of the filter tuning parameters will result in a non-white sequence for the filter measurement residuals. The residual tuning technique uses this information to estimate corrections to those tuning parameters. The actual implementation results in a set of sequential equations that run in parallel with the Kalman filter. Equations for the estimation of the measurement noise have also been developed. These algorithms are used to estimate the process noise and measurement noise for the Wide Field Infrared Explorer star tracker and gyro.

Tuning without over-tuning: parametric uncertainty quantification for the NEMO ocean model

NASA Astrophysics Data System (ADS)

Williamson, Daniel B.; Blaker, Adam T.; Sinha, Bablu

2017-04-01

In this paper we discuss climate model tuning and present an iterative automatic tuning method from the statistical science literature. The method, which we refer to here as iterative refocussing (though also known as history matching), avoids many of the common pitfalls of automatic tuning procedures that are based on optimisation of a cost function, principally the over-tuning of a climate model due to using only partial observations. This avoidance comes by seeking to rule out parameter choices that we are confident could not reproduce the observations, rather than seeking the model that is closest to them (a procedure that risks over-tuning). We comment on the state of climate model tuning and illustrate our approach through three waves of iterative refocussing of the NEMO (Nucleus for European Modelling of the Ocean) ORCA2 global ocean model run at 2° resolution. We show how at certain depths the anomalies of global mean temperature and salinity in a standard configuration of the model exceeds 10 standard deviations away from observations and show the extent to which this can be alleviated by iterative refocussing without compromising model performance spatially. We show how model improvements can be achieved by simultaneously perturbing multiple parameters, and illustrate the potential of using low-resolution ensembles to tune NEMO ORCA configurations at higher resolutions.

Normalization of neuronal responses in cortical area MT across signal strengths and motion directions

PubMed Central

Xiao, Jianbo; Niu, Yu-Qiong; Wiesner, Steven

2014-01-01

Multiple visual stimuli are common in natural scenes, yet it remains unclear how multiple stimuli interact to influence neuronal responses. We investigated this question by manipulating relative signal strengths of two stimuli moving simultaneously within the receptive fields (RFs) of neurons in the extrastriate middle temporal (MT) cortex. Visual stimuli were overlapping random-dot patterns moving in two directions separated by 90°. We first varied the motion coherence of each random-dot pattern and characterized, across the direction tuning curve, the relationship between neuronal responses elicited by bidirectional stimuli and by the constituent motion components. The tuning curve for bidirectional stimuli showed response normalization and can be accounted for by a weighted sum of the responses to the motion components. Allowing nonlinear, multiplicative interaction between the two component responses significantly improved the data fit for some neurons, and the interaction mainly had a suppressive effect on the neuronal response. The weighting of the component responses was not fixed but dependent on relative signal strengths. When two stimulus components moved at different coherence levels, the response weight for the higher-coherence component was significantly greater than that for the lower-coherence component. We also varied relative luminance levels of two coherently moving stimuli and found that MT response weight for the higher-luminance component was also greater. These results suggest that competition between multiple stimuli within a neuron's RF depends on relative signal strengths of the stimuli and that multiplicative nonlinearity may play an important role in shaping the response tuning for multiple stimuli. PMID:24899674

Damping-tunable energy-harvesting vehicle damper with multiple controlled generators: Design, modeling and experiments

NASA Astrophysics Data System (ADS)

Xie, Longhan; Li, Jiehong; Li, Xiaodong; Huang, Ledeng; Cai, Siqi

2018-01-01

Hydraulic dampers are used to decrease the vibration of a vehicle, where vibration energy is dissipated as heat. In addition to resulting in energy waste, the damping coefficient in hydraulic dampers cannot be changed during operation. In this paper, an energy-harvesting vehicle damper was proposed to replace traditional hydraulic dampers. The goal is not only to recover kinetic energy from suspension vibration but also to change the damping coefficient during operation according to road conditions. The energy-harvesting damper consists of multiple generators that are independently controlled by switches. One of these generators connects to a tunable resistor for fine tuning the damping coefficient, while the other generators are connected to a control and rectifying circuit, each of which both regenerates electricity and provides a constant damping coefficient. A mathematical model was built to investigate the performance of the energy-harvesting damper. By controlling the number of switched-on generators and adjusting the value of the external tunable resistor, the damping can be fine tuned according to the requirement. In addition to the capability of damping tuning, the multiple controlled generators can output a significant amount of electricity. A prototype was built to test the energy-harvesting damper design. Experiments on an MTS testing system were conducted, with results that validated the theoretical analysis. Experiments show that changing the number of switched-on generators can obviously tune the damping coefficient of the damper and simultaneously produce considerable electricity.

Engine Tune-up Service. Unit 2: Charging System. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Richardson, Roger L.; Bacon, E. Miles

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 2, Charging System, available separately as CE 031 208. Focus of the posttest is on the testing of the charging system. One multiple choice posttest is provided, that covers the three performance objectives contained in the unit. (No answer key is…

Engine Tune-Up Service. Unit 5: Fuel and Carburetion Systems. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Morse, David T.

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 5, Fuel and Carburetion Systems; available separately as CE 031 217. Focus of the posttests is the inspecting and servicing of the fuel and carburetion systems. One multiple choice posttest is provided that covers the 10 performance objectives…

Modal analysis using a Fourier analyzer, curve-fitting, and modal tuning

NASA Technical Reports Server (NTRS)

Craig, R. R., Jr.; Chung, Y. T.

1981-01-01

The proposed modal test program differs from single-input methods in that preliminary data may be acquired using multiple inputs, and modal tuning procedures may be employed to define closely spaced frquency modes more accurately or to make use of frequency response functions (FRF's) which are based on several input locations. In some respects the proposed modal test proram resembles earlier sine-sweep and sine-dwell testing in that broadband FRF's are acquired using several input locations, and tuning is employed to refine the modal parameter estimates. The major tasks performed in the proposed modal test program are outlined. Data acquisition and FFT processing, curve fitting, and modal tuning phases are described and examples are given to illustrate and evaluate them.

99Tc atom counting by quadrupole ICP-MS. Optimisation of the instrumental response

NASA Astrophysics Data System (ADS)

Más, José L.; Garcia-León, Manuel; Bolívar, Juan P.

2002-05-01

In this paper, an extensive work is done on the specific tune of a conventional ICP-MS for 99Tc atom counting. For this, two methods have been used and compared: the partial variable control method and the 5D Simplex method. Instrumental limits of detection of 0.2 and 0.8 ppt, respectively, were obtained. They are noticeably lower than that found with the automatic tune method of the spectrometer, 47 ppt, which shows the need of a specific tune when very low levels of 99Tc have to be determined. A study is presented on the mass interferences for 99Tc. Our experiments show that the formation of polyatomic atoms or refractory oxides as well as 98Mo hydrides seem to be irrelevant for 99Tc atom counting. The opposite occurs with the presence of isobaric interferences, i.e. 99Ru, and the effect of abundance sensitivity, or low-mass resolution, which can modify the response at m/ z=99 to a non-negligible extent.

Reducing the fine-tuning of gauge-mediated SUSY breaking

NASA Astrophysics Data System (ADS)

Casas, J. Alberto; Moreno, Jesús M.; Robles, Sandra; Rolbiecki, Krzysztof

2016-08-01

Despite their appealing features, models with gauge-mediated supersymmetry breaking (GMSB) typically present a high degree of fine-tuning, due to the initial absence of the top trilinear scalar couplings, A_t=0. In this paper, we carefully evaluate such a tuning, showing that is worse than per mil in the minimal model. Then, we examine some existing proposals to generate A_t≠ 0 term in this context. We find that, although the stops can be made lighter, usually the tuning does not improve (it may be even worse), with some exceptions, which involve the generation of A_t at one loop or tree level. We examine both possibilities and propose a conceptually simplified version of the latter; which is arguably the optimum GMSB setup (with minimal matter content), concerning the fine-tuning issue. The resulting fine-tuning is better than one per mil, still severe but similar to other minimal supersymmetric standard model constructions. We also explore the so-called "little A_t^2/m^2 problem", i.e. the fact that a large A_t-term is normally accompanied by a similar or larger sfermion mass, which typically implies an increase in the fine-tuning. Finally, we find the version of GMSB for which this ratio is optimized, which, nevertheless, does not minimize the fine-tuning.

Parameter optimization of an inerter-based isolator for passive vibration control of Michelangelo's Rondanini Pietà

NASA Astrophysics Data System (ADS)

Siami, A.; Karimi, H. R.; Cigada, A.; Zappa, E.; Sabbioni, E.

2018-01-01

Preserving cultural heritage against earthquake and ambient vibrations can be an attractive topic in the field of vibration control. This paper proposes a passive vibration isolator methodology based on inerters for improving the performance of the isolation system of the famous statue of Michelangelo Buonarroti Pietà Rondanini. More specifically, a five-degree-of-freedom (5DOF) model of the statue and the anti-seismic and anti-vibration base is presented and experimentally validated. The parameters of this model are tuned according to the experimental tests performed on the assembly of the isolator and the structure. Then, the developed model is used to investigate the impact of actuation devices such as tuned mass-damper (TMD) and tuned mass-damper-inerter (TMDI) in vibration reduction of the structure. The effect of implementation of TMDI on the 5DOF model is shown based on physical limitations of the system parameters. Simulation results are provided to illustrate effectiveness of the passive element of TMDI in reduction of the vibration transmitted to the statue in vertical direction. Moreover, the optimal design parameters of the passive system such as frequency and damping coefficient will be calculated using two different performance indexes. The obtained optimal parameters have been evaluated by using two different optimization algorithms: the sequential quadratic programming method and the Firefly algorithm. The results prove significant reduction in the transmitted vibration to the structure in the presence of the proposed tuned TMDI, without imposing a large amount of mass or modification to the structure of the isolator.

Revisiting the decoupling effects in the running of the Cosmological Constant

NASA Astrophysics Data System (ADS)

Antipin, Oleg; Melić, Blaženka

2017-09-01

We revisit the decoupling effects associated with heavy particles in the renormalization group running of the vacuum energy in a mass-dependent renormalization scheme. We find the running of the vacuum energy stemming from the Higgs condensate in the entire energy range and show that it behaves as expected from the simple dimensional arguments meaning that it exhibits the quadratic sensitivity to the mass of the heavy particles in the infrared regime. The consequence of such a running to the fine-tuning problem with the measured value of the Cosmological Constant is analyzed and the constraint on the mass spectrum of a given model is derived. We show that in the Standard Model (SM) this fine-tuning constraint is not satisfied while in the massless theories this constraint formally coincides with the well known Veltman condition. We also provide a remarkably simple extension of the SM where saturation of this constraint enables us to predict the radiative Higgs mass correctly. Generalization to constant curvature spaces is also given.

Investigation of earthquake factor for optimum tuned mass dampers

NASA Astrophysics Data System (ADS)

Nigdeli, Sinan Melih; Bekdaş, Gebrail

2012-09-01

In this study the optimum parameters of tuned mass dampers (TMD) are investigated under earthquake excitations. An optimization strategy was carried out by using the Harmony Search (HS) algorithm. HS is a metaheuristic method which is inspired from the nature of musical performances. In addition to the HS algorithm, the results of the optimization objective are compared with the results of the other documented method and the corresponding results are eliminated. In that case, the best optimum results are obtained. During the optimization, the optimum TMD parameters were searched for single degree of freedom (SDOF) structure models with different periods. The optimization was done for different earthquakes separately and the results were compared.

Engine Tune-Up Service. Unit 1: Battery and Cranking System. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Goodson-Roberts, Ludy; And Others

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 1, Battery and Cranking System. Focus of the posttests is the testing of the battery and cranking system. Four multiple choice posttests are provided, one for each of the performance objectives contained in the unit. (No answer keys are provided.)…

Natural implementation of neutralino dark matter

NASA Astrophysics Data System (ADS)

King, Steve F.; Roberts, Jonathan P.

2006-09-01

The prediction of neutralino dark matter is generally regarded as one of the successes of the Minimal Supersymmetric Standard Model (MSSM). However the successful regions of parameter space allowed by WMAP and collider constraints are quite restricted. We discuss fine-tuning with respect to both dark matter and Electroweak Symmetry Breaking (EWSB) and explore regions of MSSM parameter space with non-universal gaugino and third family scalar masses in which neutralino dark matter may be implemented naturally. In particular allowing non-universal gauginos opens up the bulk region that allows Bino annihilation via t-channel slepton exchange, leading to ``supernatural dark matter'' corresponding to no fine-tuning at all with respect to dark matter. By contrast we find that the recently proposed ``well tempered neutralino'' regions involve substantial fine-tuning of MSSM parameters in order to satisfy the dark matter constraints, although the fine tuning may be ameliorated if several annihilation channels act simultaneously. Although we have identified regions of ``supernatural dark matter'' in which there is no fine tuning to achieve successful dark matter, the usual MSSM fine tuning to achieve EWSB always remains.

Human neural tuning estimated from compound action potentials in normal hearing human volunteers

NASA Astrophysics Data System (ADS)

Verschooten, Eric; Desloovere, Christian; Joris, Philip X.

2015-12-01

The sharpness of cochlear frequency tuning in humans is debated. Evoked otoacoustic emissions and psychophysical measurements suggest sharper tuning in humans than in laboratory animals [15], but this is disputed based on comparisons of behavioral and electrophysiological measurements across species [14]. Here we used evoked mass potentials to electrophysiologically quantify tuning (Q10) in humans. We combined a notched noise forward masking paradigm [9] with the recording of trans tympanic compound action potentials (CAP) from masked probe tones in awake human and anesthetized monkey (Macaca mulatta). We compare our results to data obtained with the same paradigm in cat and chinchilla [16], and find that CAP-Q10values in human are ˜1.6x higher than in cat and chinchilla and ˜1.3x higher than in monkey. To estimate frequency tuning of single auditory nerve fibers (ANFs) in humans, we derive conversion functions from ANFs in cat, chinchilla, and monkey and apply these to the human CAP measurements. The data suggest that sharp cochlear tuning is a feature of old-world primates.

Optimizing tuning masses for helicopter rotor blade vibration reduction including computed airloads and comparison with test data

NASA Technical Reports Server (NTRS)

Pritchard, Jocelyn I.; Adelman, Howard M.; Walsh, Joanne L.; Wilbur, Matthew L.

1992-01-01

The development and validation of an optimization procedure to systematically place tuning masses along a rotor blade span to minimize vibratory loads are described. The masses and their corresponding locations are the design variables that are manipulated to reduce the harmonics of hub shear for a four-bladed rotor system without adding a large mass penalty. The procedure incorporates a comprehensive helicopter analysis to calculate the airloads. Predicting changes in airloads due to changes in design variables is an important feature of this research. The procedure was applied to a one-sixth, Mach-scaled rotor blade model to place three masses and then again to place six masses. In both cases the added mass was able to achieve significant reductions in the hub shear. In addition, the procedure was applied to place a single mass of fixed value on a blade model to reduce the hub shear for three flight conditions. The analytical results were compared to experimental data from a wind tunnel test performed in the Langley Transonic Dynamics Tunnel. The correlation of the mass location was good and the trend of the mass location with respect to flight speed was predicted fairly well. However, it was noted that the analysis was not entirely successful at predicting the absolute magnitudes of the fixed system loads.

Turbine blade with tuned damping structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Christian X.; Messmann, Stephen J.

2015-09-01

A turbine blade is provided comprising: a root; an airfoil comprising an external wall extending radially from the root and having a radially outermost portion; and a damping structure. The external wall may comprise first and second side walls joined together to define an inner cavity of the airfoil. The damping structure may be positioned within the airfoil inner cavity and coupled to the airfoil so as to define a tuned mass damper.

Spatiotemporal source tuning filter bank for multiclass EEG based brain computer interfaces.

PubMed

Acharya, Soumyadipta; Mollazadeh, Moshen; Murari, Kartikeya; Thakor, Nitish

2006-01-01

Non invasive brain-computer interfaces (BCI) allow people to communicate by modulating features of their electroencephalogram (EEG). Spatiotemporal filtering has a vital role in multi-class, EEG based BCI. In this study, we used a novel combination of principle component analysis, independent component analysis and dipole source localization to design a spatiotemporal multiple source tuning (SPAMSORT) filter bank, each channel of which was tuned to the activity of an underlying dipole source. Changes in the event-related spectral perturbation (ERSP) were measured and used to train a linear support vector machine to classify between four classes of motor imagery tasks (left hand, right hand, foot and tongue) for one subject. ERSP values were significantly (p<0.01) different across tasks and better (p<0.01) than conventional spatial filtering methods (large Laplacian and common average reference). Classification resulted in an average accuracy of 82.5%. This approach could lead to promising BCI applications such as control of a prosthesis with multiple degrees of freedom.

Do we live in the best of all possible worlds? The fine-tuning of the constants of nature

NASA Astrophysics Data System (ADS)

Naumann, Thomas

2017-12-01

Our existence depends on a variety of constants which appear to be extremely fine-tuned to allow for the existence of life. These include the number of spatial dimensions, the strengths of the forces, the masses of the particles, the composition of the Universe and others. On the occasion of the 300th anniversary of the death of G.W. Leibniz we discuss the question of whether we live in the "Best of all Worlds". The hypothesis of a multiverse could explain the mysterious fine tuning of so many fundamental quantities. Anthropic arguments are critically reviewed.

Real-Time Ozone Detection Based on a Microfabricated Quartz Crystal Tuning Fork Sensor

PubMed Central

Wang, Rui; Tsow, Francis; Zhang, Xuezhi; Peng, Jhih-Hong; Forzani, Erica S.; Chen, Yongsheng; Crittenden, John C.; Destaillats, Hugo; Tao, Nongjian

2009-01-01

A chemical sensor for ozone based on an array of microfabricated tuning forks is described. The tuning forks are highly sensitive and stable, with low power consumption and cost. The selective detection is based on the specific reaction of the polymer with ozone. With a mass detection limit of ∼2 pg/mm2 and response time of 1 second, the sensor coated with a polymer sensing material can detect ppb-level ozone in air. The sensor is integrated into a miniaturized wearable device containing a detection circuit, filtration, battery and wireless communication chip, which is ideal for personal and microenvironmental chemical exposure monitoring. PMID:22346720

An approach to tune the amplitude of surface ripple patterns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Tanuj; Kanjilal, D.; Kumar, Ashish

An approach is presented to tune the amplitude of ripple patterns using ion beam. By varying the depth location of amorphous/crystalline interface, ripple patterns of different amplitude with similar wavelength were grown on the surface of Si (100) using 50 keV Ar{sup +} beam irradiation. Atomic force microscopy study demonstrates the tuning of amplitude of ripples patterns for wide range. Rutherford backscattering channeling measurement was performed to measure the depth location of amorphous/crystalline interface. It is postulated that the ion beam stimulated solid flow inside the amorphous layer controls the wavelength, whereas mass rearrangement at amorphous/crystalline interface controls the amplitude.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Kewisch, J.; Huang, H.

At RHIC, the spin polarization is preserved with a pair of Siberian snakes on the oppo- site sides in each ring. The polarized proton beam with finite spin tune spread might cross spin resonances multiple times in two cases, one is when beam going through strong spin intrinsic resonances during acceleration, the other is when sweeping spin flipper’ frequency across the spin tune to flip the direction of spin polarization. The consequence is loss of spin polarization in both cases. Therefore, a scheme of min- imizing the spin tune spread by matching the dispersion primes at the two snakes wasmore » introduced based on the fact that the spin tune spread is proportional to the difference of dispersion primes at the two snakes. The scheme was implemented at fixed energies for the spin flipper study and during beam acceleration for better spin polarization transmission efficiency. The effect of minimizing the spin tune spread by matching the dispersion primes was observed and confirmed experimentally. The principle of minimizing the spin tune spread by matching the dispersion primes, the impact on the beam optics, and the effect of a narrower spin tune spread are presented in this report.« less

Development of monofilar rotor hub vibration absorber

NASA Technical Reports Server (NTRS)

Duh, J.; Miao, W.

1983-01-01

A design and ground test program was conducted to study the performance of the monofilar absorber for vibration reduction on a four-bladed helicopter. A monofilar is a centrifugal tuned two degree-of-freedom rotor hub absorber that provides force attenuation at two frequencies using the same dynamic mass. Linear and non-linear analyses of the coupled monofilar/airframe system were developed to study tuning and attenuation characteristics. Based on the analysis, a design was fabricated and impact bench tests verified the calculated non-rotating natural frequencies and mode shapes. Performance characteristics were measured using a rotating absorber test facility. These tests showed significant attenuation of fixed-system 4P hub motions due to 3P inplane rotating-system hub forces. In addition, detuning effects of the 3P monofilar modal response were small due to the nonlinearities and tuning pin slippage. However, attenuation of 4P hub motions due to 5P inplane hub forces was poor. The performance of the 5P monofilar modal response was degraded by torsional motion of the dynamic mass relative to the support arm which resulted in binding of the dynamic components. Analytical design studies were performed to evaluate this torsional motion problem. An alternative design is proposed which may alleviate the torsional motion of the dynamic mass.

Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras.

PubMed

Li, Zhenyu; Wang, Bin; Liu, Hong

2016-08-30

Satellite capturing with free-floating space robots is still a challenging task due to the non-fixed base and unknown mass property issues. In this paper gyro and eye-in-hand camera data are adopted as an alternative choice for solving this problem. For this improved system, a new modeling approach that reduces the complexity of system control and identification is proposed. With the newly developed model, the space robot is equivalent to a ground-fixed manipulator system. Accordingly, a self-tuning control scheme is applied to handle such a control problem including unknown parameters. To determine the controller parameters, an estimator is designed based on the least-squares technique for identifying the unknown mass properties in real time. The proposed method is tested with a credible 3-dimensional ground verification experimental system, and the experimental results confirm the effectiveness of the proposed control scheme.

Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras

PubMed Central

Li, Zhenyu; Wang, Bin; Liu, Hong

2016-01-01

Satellite capturing with free-floating space robots is still a challenging task due to the non-fixed base and unknown mass property issues. In this paper gyro and eye-in-hand camera data are adopted as an alternative choice for solving this problem. For this improved system, a new modeling approach that reduces the complexity of system control and identification is proposed. With the newly developed model, the space robot is equivalent to a ground-fixed manipulator system. Accordingly, a self-tuning control scheme is applied to handle such a control problem including unknown parameters. To determine the controller parameters, an estimator is designed based on the least-squares technique for identifying the unknown mass properties in real time. The proposed method is tested with a credible 3-dimensional ground verification experimental system, and the experimental results confirm the effectiveness of the proposed control scheme. PMID:27589748

Exploring natural supersymmetry at the LHC

NASA Astrophysics Data System (ADS)

Nasir, Fariha

This dissertation demonstrates how a variety of supersymmetric grand unified theories can resolve the little hierarchy problem in the minimal supersymmetric standard model and also explain the observed deviation in the anomalous magnetic moment of the muon. The origin of the little hierarchy problem lies in the sensitive manner in which the Z boson mass depends on parameters that can be much larger than its mass. Large values of these parameters imply that a large fine tuning is required to obtain the correct Z boson mass. With large fine tuning supersymmetry appears unnatural which is why models that attempt to resolve this problem are referred to as natural SUSY models. We show that a possible way to exhibit natural supersymmetry is to assume non-universal gauginos in a class of supersymmetric grand unified models. We further show that considering non-universal gauginos in a class of supersymmetric models can help explain the apparent anomaly in the magnetic moment of the muon.

Origin of the fundamental plane of elliptical galaxies in the Coma cluster without fine-tuning

NASA Astrophysics Data System (ADS)

Chiu, Mu-Chen; Ko, Chung-Ming; Shu, Chenggang

2017-03-01

Thirty years after the discovery of the fundamental plane, explanations of the tilt of the fundamental plane with respect to the virial plane are still in need of fine-tuning. In this paper, we try to explore the origin of this tilt from the perspective of modified Newtonian dynamics (MOND) by applying the 16 Coma galaxies available in J. Thomas et al. [Mon. Not. R. Astron. Soc. 415, 545 (2011), 10.1111/j.1365-2966.2011.18725.x]. Based on the mass models that can reproduce de Vaucouleurs' law closely, we find that the tilt of the traditional fundamental plane is naturally explained by the simple form of the MONDian interpolating function, if we assume a well motivated choice of anisotropic velocity distribution, and adopt the Kroupa or Salpeter stellar mass-to-light ratio. Our analysis does not necessarily rule out a varying stellar mass-to-light ratio.

Particle swarm optimization of the sensitivity of a cryogenic gravitational wave detector

NASA Astrophysics Data System (ADS)

Michimura, Yuta; Komori, Kentaro; Nishizawa, Atsushi; Takeda, Hiroki; Nagano, Koji; Enomoto, Yutaro; Hayama, Kazuhiro; Somiya, Kentaro; Ando, Masaki

2018-06-01

Cryogenic cooling of the test masses of interferometric gravitational wave detectors is a promising way to reduce thermal noise. However, cryogenic cooling limits the incident power to the test masses, which limits the freedom of shaping the quantum noise. Cryogenic cooling also requires short and thick suspension fibers to extract heat, which could result in the worsening of thermal noise. Therefore, careful tuning of multiple parameters is necessary in designing the sensitivity of cryogenic gravitational wave detectors. Here, we propose the use of particle swarm optimization to optimize the parameters of these detectors. We apply it for designing the sensitivity of the KAGRA detector, and show that binary neutron star inspiral range can be improved by 10%, just by retuning seven parameters of existing components. We also show that the sky localization of GW170817-like binaries can be further improved by a factor of 1.6 averaged across the sky. Our results show that particle swarm optimization is useful for designing future gravitational wave detectors with higher dimensionality in the parameter space.

An Adaptive Kalman Filter Using a Simple Residual Tuning Method

NASA Technical Reports Server (NTRS)

Harman, Richard R.

1999-01-01

One difficulty in using Kalman filters in real world situations is the selection of the correct process noise, measurement noise, and initial state estimate and covariance. These parameters are commonly referred to as tuning parameters. Multiple methods have been developed to estimate these parameters. Most of those methods such as maximum likelihood, subspace, and observer Kalman Identification require extensive offline processing and are not suitable for real time processing. One technique, which is suitable for real time processing, is the residual tuning method. Any mismodeling of the filter tuning parameters will result in a non-white sequence for the filter measurement residuals. The residual tuning technique uses this information to estimate corrections to those tuning parameters. The actual implementation results in a set of sequential equations that run in parallel with the Kalman filter. A. H. Jazwinski developed a specialized version of this technique for estimation of process noise. Equations for the estimation of the measurement noise have also been developed. These algorithms are used to estimate the process noise and measurement noise for the Wide Field Infrared Explorer star tracker and gyro.

Natural tuning: towards a proof of concept

NASA Astrophysics Data System (ADS)

Dubovsky, Sergei; Gorbenko, Victor; Mirbabayi, Mehrdad

2013-09-01

The cosmological constant problem and the absence of new natural physics at the electroweak scale, if confirmed by the LHC, may either indicate that the nature is fine-tuned or that a refined notion of naturalness is required. We construct a family of toy UV complete quantum theories providing a proof of concept for the second possibility. Low energy physics is described by a tuned effective field theory, which exhibits relevant interactions not protected by any symmetries and separated by an arbitrary large mass gap from the new "gravitational" physics, represented by a set of irrelevant operators. Nevertheless, the only available language to describe dynamics at all energy scales does not require any fine-tuning. The interesting novel feature of this construction is that UV physics is not described by a fixed point, but rather exhibits asymptotic fragility. Observation of additional unprotected scalars at the LHC would be a smoking gun for this scenario. Natural tuning also favors TeV scale unification.

Kinetics of a Collagen-Like Polypeptide Fragmentation after Mid-IR Free-Electron Laser Ablation

PubMed Central

Zavalin, Andrey; Hachey, David L.; Sundaramoorthy, Munirathinam; Banerjee, Surajit; Morgan, Steven; Feldman, Leonard; Tolk, Norman; Piston, David W.

2008-01-01

Tissue ablation with mid-infrared irradiation tuned to collagen vibrational modes results in minimal collateral damage. The hypothesis for this effect includes selective scission of protein molecules and excitation of surrounding water molecules, with the scission process currently favored. In this article, we describe the postablation infrared spectral decay kinetics in a model collagen-like peptide (Pro-Pro-Gly)10. We find that the decay is exponential with different decay times for other, simpler dipeptides. Furthermore, we find that collagen-like polypeptides, such as (Pro-Pro-Gly)10, show multiple decay times, indicating multiple scission locations and cross-linking to form longer chain molecules. In combination with data from high-resolution mass spectrometry, we interpret these products to result from the generation of reactive intermediates, such as free radicals, cyanate ions, and isocyanic acid, which can form cross-links and protein adducts. Our results lead to a more complete explanation of the reduced collateral damage resulting from infrared laser irradiation through a mechanism involving cross-linking in which collagen-like molecules form a network of cross-linked fibers. PMID:18441025

Valley polarization in bismuth

NASA Astrophysics Data System (ADS)

Fauque, Benoit

2013-03-01

The electronic structure of certain crystal lattices can contain multiple degenerate valleys for their charge carriers to occupy. The principal challenge in the development of valleytronics is to lift the valley degeneracy of charge carriers in a controlled way. In bulk semi-metallic bismuth, the Fermi surface includes three cigar-shaped electron valleys lying almost perpendicular to the high symmetry axis known as the trigonal axis. The in-plane mass anisotropy of each valley exceeds 200 as a consequence of Dirac dispersion, which drastically reduces the effective mass along two out of the three orientations. According to our recent study of angle-dependent magnetoresistance in bismuth, a flow of Dirac electrons along the trigonal axis is extremely sensitive to the orientation of in-plane magnetic field. Thus, a rotatable magnetic field can be used as a valley valve to tune the contribution of each valley to the total conductivity. As a consequence of a unique combination of high mobility and extreme mass anisotropy in bismuth, the effect is visible even at room temperature in a magnetic field of 1 T. Thus, a modest magnetic field can be used as a valley valve in bismuth. The results of our recent investigation of angle-dependent magnetoresistance in other semi-metals and doped semiconductors suggest that a rotating magnetic field can behave as a valley valve in a multi-valley system with sizeable mass anisotropy.

Black hole formation from the gravitational collapse of a nonspherical network of structures

NASA Astrophysics Data System (ADS)

Delgado Gaspar, Ismael; Hidalgo, Juan Carlos; Sussman, Roberto A.; Quiros, Israel

2018-05-01

We examine the gravitational collapse and black hole formation of multiple nonspherical configurations constructed from Szekeres dust models with positive spatial curvature that smoothly match to a Schwarzschild exterior. These configurations are made of an almost spherical central core region surrounded by a network of "pancake-like" overdensities and voids with spatial positions prescribed through standard initial conditions. We show that a full collapse into a focusing singularity, without shell crossings appearing before the formation of an apparent horizon, is not possible unless the full configuration becomes exactly or almost spherical. Seeking for black hole formation, we demand that shell crossings are covered by the apparent horizon. This requires very special fine-tuned initial conditions that impose very strong and unrealistic constraints on the total black hole mass and full collapse time. As a consequence, nonspherical nonrotating dust sources cannot furnish even minimally realistic toy models of black hole formation at astrophysical scales: demanding realistic collapse time scales yields huge unrealistic black hole masses, while simulations of typical astrophysical black hole masses collapse in unrealistically small times. We note, however, that the resulting time-mass constraint is compatible with early Universe models of primordial black hole formation, suitable in early dust-like environments. Finally, we argue that the shell crossings appearing when nonspherical dust structures collapse are an indicator that such structures do not form galactic mass black holes but virialize into stable stationary objects.

Tunable Micro- and Nanomechanical Resonators

PubMed Central

Zhang, Wen-Ming; Hu, Kai-Ming; Peng, Zhi-Ke; Meng, Guang

2015-01-01

Advances in micro- and nanofabrication technologies have enabled the development of novel micro- and nanomechanical resonators which have attracted significant attention due to their fascinating physical properties and growing potential applications. In this review, we have presented a brief overview of the resonance behavior and frequency tuning principles by varying either the mass or the stiffness of resonators. The progress in micro- and nanomechanical resonators using the tuning electrode, tuning fork, and suspended channel structures and made of graphene have been reviewed. We have also highlighted some major influencing factors such as large-amplitude effect, surface effect and fluid effect on the performances of resonators. More specifically, we have addressed the effects of axial stress/strain, residual surface stress and adsorption-induced surface stress on the sensing and detection applications and discussed the current challenges. We have significantly focused on the active and passive frequency tuning methods and techniques for micro- and nanomechanical resonator applications. On one hand, we have comprehensively evaluated the advantages and disadvantages of each strategy, including active methods such as electrothermal, electrostatic, piezoelectrical, dielectric, magnetomotive, photothermal, mode-coupling as well as tension-based tuning mechanisms, and passive techniques such as post-fabrication and post-packaging tuning processes. On the other hand, the tuning capability and challenges to integrate reliable and customizable frequency tuning methods have been addressed. We have additionally concluded with a discussion of important future directions for further tunable micro- and nanomechanical resonators. PMID:26501294

Assigning Quantitative Function to Post-Translational Modifications Reveals Multiple Sites of Phosphorylation That Tune Yeast Pheromone Signaling Output

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pincus, David; Ryan, Christopher J.; Smith, Richard D.

2013-03-12

Cell signaling systems transmit information by post-­translationally modifying signaling proteins, often via phosphorylation. While thousands of sites of phosphorylation have been identified in proteomic studies, the vast majority of sites have no known function. Assigning functional roles to the catalog of uncharacterized phosphorylation sites is a key research challenge. Here we present a general approach to address this challenge and apply it to a prototypical signaling pathway, the pheromone response pathway in Saccharomyces cerevisiae. The pheromone pathway includes a mitogen activated protein kinase (MAPK) cascade activated by a G-­protein coupled receptor (GPCR). We used mass spectrometry-based proteomics to identify sitesmore » whose phosphorylation changed when the system was active, and evolutionary conservation to assign priority to a list of candidate MAPK regulatory sites. We made targeted alterations in those sites, and measured the effects of the mutations on pheromone pathway output in single cells. Our work identified six new sites that quantitatively tuned system output. We developed simple computational models to find system architectures that recapitulated the quantitative phenotypes of the mutants. Our results identify a number of regulated phosphorylation events that contribute to adjust the input-­output relationship of this model eukaryotic signaling system. We believe this combined approach constitutes a general means not only to reveal modification sites required to turn a pathway on and off, but also those required for more subtle quantitative effects that tune pathway output. Our results further suggest that relatively small quantitative influences from individual regulatory phosphorylation events endow signaling systems with plasticity that evolution may exploit to quantitatively tailor signaling outcomes.« less

Tuning orb spider glycoprotein glue performance to habitat humidity.

PubMed

Opell, Brent D; Jain, Dharamdeep; Dhinojwala, Ali; Blackledge, Todd A

2018-03-26

Orb-weaving spiders use adhesive threads to delay the escape of insects from their webs until the spiders can locate and subdue the insects. These viscous threads are spun as paired flagelliform axial fibers coated by a cylinder of solution derived from the aggregate glands. As low molecular mass compounds (LMMCs) in the aggregate solution attract atmospheric moisture, the enlarging cylinder becomes unstable and divides into droplets. Within each droplet an adhesive glycoprotein core condenses. The plasticity and axial line extensibility of the glycoproteins are maintained by hygroscopic LMMCs. These compounds cause droplet volume to track changes in humidity and glycoprotein viscosity to vary approximately 1000-fold over the course of a day. Natural selection has tuned the performance of glycoprotein cores to the humidity of a species' foraging environment by altering the composition of its LMMCs. Thus, species from low-humidity habits have more hygroscopic threads than those from humid forests. However, at their respective foraging humidities, these species' glycoproteins have remarkably similar viscosities, ensuring optimal droplet adhesion by balancing glycoprotein adhesion and cohesion. Optimal viscosity is also essential for integrating the adhesion force of multiple droplets. As force is transferred to a thread's support line, extending droplets draw it into a parabolic configuration, implementing a suspension bridge mechanism that sums the adhesive force generated over the thread span. Thus, viscous capture threads extend an orb spider's phenotype as a highly integrated complex of large proteins and small molecules that function as a self-assembling, highly tuned, environmentally responsive, adhesive biomaterial. Understanding the synergistic role of chemistry and design in spider adhesives, particularly the ability to stick in wet conditions, provides insight in designing synthetic adhesives for biomedical applications. © 2018. Published by The Company of Biologists Ltd.

Reaching to multiple targets when standing: the spatial organization of feedforward postural adjustments.

PubMed

Leonard, Julia A; Brown, Ryan H; Stapley, Paul J

2009-04-01

We examined the spatial organization of feedforward postural adjustments produced prior to and during voluntary arm reaching movements executed while standing. We sought to investigate whether the activity of postural muscles before and during reaching was directionally tuned and whether a strategy of horizontal force constraint could be observed. To this end, eight human subjects executed self-paced reach-to-point movements on the random illumination of one of 13 light targets placed within a 180 degrees array centered along the midline of the body. Analysis was divided into two periods: a first corresponding to the 250 ms preceding the onset of the reaching movements (termed pPA period) and a second 250-ms period immediately preceding target attainment (the aPA period). For both periods, electromyographic activity of the lower limb muscles revealed a clear directional tuning, with groups of muscles being activated for similar directions of reach. Analysis of horizontal ground reaction forces supported the existence of a force constraint strategy only for the pPA period, however, with those in the aPA period being more widely dispersed. We suggest that the strategy adopted for feedforward pPAs is one where the tuned muscle synergies constrain the forces diagonally away from the center of mass (CoM) to move it within the support base. However, the need to control for final finger and body position for each target during the aPA phase resulted in a distribution of vectors across reaching directions. Overall, our results would support the idea that endpoint limb force during postural tasks depends on the use of functional muscle synergies, which are used to displace the CoM or decelerate the body at the end of the reach.

Multi-Objective Control Optimization for Greenhouse Environment Using Evolutionary Algorithms

PubMed Central

Hu, Haigen; Xu, Lihong; Wei, Ruihua; Zhu, Bingkun

2011-01-01

This paper investigates the issue of tuning the Proportional Integral and Derivative (PID) controller parameters for a greenhouse climate control system using an Evolutionary Algorithm (EA) based on multiple performance measures such as good static-dynamic performance specifications and the smooth process of control. A model of nonlinear thermodynamic laws between numerous system variables affecting the greenhouse climate is formulated. The proposed tuning scheme is tested for greenhouse climate control by minimizing the integrated time square error (ITSE) and the control increment or rate in a simulation experiment. The results show that by tuning the gain parameters the controllers can achieve good control performance through step responses such as small overshoot, fast settling time, and less rise time and steady state error. Besides, it can be applied to tuning the system with different properties, such as strong interactions among variables, nonlinearities and conflicting performance criteria. The results implicate that it is a quite effective and promising tuning method using multi-objective optimization algorithms in the complex greenhouse production. PMID:22163927

Mass-stiffness substructuring of an elastic metasurface for full transmission beam steering

NASA Astrophysics Data System (ADS)

Lee, Hyuk; Lee, Jun Kyu; Seung, Hong Min; Kim, Yoon Young

2018-03-01

The metasurface concept has a significant potential due to its novel wavefront-shaping functionalities that can be critically useful for ultrasonic and solid wave-based applications. To achieve the desired functionalities, elastic metasurfaces should cover full 2π phase shift and also acquire full transmission within subwavelength scale. However, they have not been explored much with respect to the elastic regime, because the intrinsic proportionality of mass-stiffness within the continuum elastic media causes an inevitable trade-off between abrupt phase shift and sufficient transmission. Our goal is to engineer an elastic metasurface that can realize an inverse relation between (amplified) effective mass and (weakened) stiffness in order to satisfy full 2π phase shift as well as full transmission. To achieve this goal, we propose a continuum elastic metasurface unit cell that is decomposed into two substructures, namely a mass-tuning substructure with a local dipolar resonator and a stiffness-tuning substructure composed of non-resonant multiply-perforated slits. We demonstrate analytically, numerically, and experimentally that this unique substructured unit cell can satisfy the required phase shift with high transmission. The substructuring enables independent tuning of the elastic properties over a wide range of values. We use a mass-spring model of the proposed continuum unit cell to investigate the working mechanism of the proposed metasurface. With the designed metasurface consisting of substructured unit cells embedded in an aluminum plate, we demonstrate that our metasurface can successfully realize anomalous steering and focusing of in-plane longitudinal ultrasonic beams. The proposed substructuring concept is expected to provide a new principle for the design of general elastic metasurfaces that can be used to efficiently engineer arbitrary wave profiles.

Low-mass neutralino dark matter in supergravity scenarios: phenomenology and naturalness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peiró, M.; Robles, S., E-mail: mpeirogarcia@gmail.com, E-mail: sandra.robles@uam.es

2017-05-01

The latest experimental results from the LHC and dark matter (DM) searches suggest that the parameter space allowed in supersymmetric theories is subject to strong reductions. These bounds are especially constraining for scenarios entailing light DM particles. Previous studies have shown that light neutralino DM in the Minimal Supersymmetric Standard Model (MSSM), with parameters defined at the electroweak scale, is still viable when the low energy spectrum of the model features light sleptons, in which case, the relic density constraint can be fulfilled. In view of this, we have investigated the viability of light neutralinos as DM candidates in themore » MSSM, with parameters defined at the grand unification scale. We have analysed the optimal choices of non-universalities in the soft supersymmetry-breaking parameters for both, gauginos and scalars, in order to avoid the stringent experimental constraints. We show that light neutralinos, with a mass as low as 25 GeV, are viable in supergravity scenarios if the gaugino mass parameters at high energy are very non universal, while the scalar masses can remain of the same order. These scenarios typically predict a very small cross section of neutralinos off protons and neutrons, thereby being very challenging for direct detection experiments. However, a potential detection of smuons and selectrons at the LHC, together with a hypothetical discovery of a gamma-ray signal from neutralino annihilations in dwarf spheroidal galaxies could shed light on this kind of solutions. Finally, we have investigated the naturalness of these scenarios, taking into account all the potential sources of tuning. Besides the electroweak fine-tuning, we have found that the tuning to reproduce the correct DM relic abundance and that to match the measured Higgs mass can also be important when estimating the total degree of naturalness.« less

Low-mass neutralino dark matter in supergravity scenarios: phenomenology and naturalness

NASA Astrophysics Data System (ADS)

Peiró, M.; Robles, S.

2017-05-01

The latest experimental results from the LHC and dark matter (DM) searches suggest that the parameter space allowed in supersymmetric theories is subject to strong reductions. These bounds are especially constraining for scenarios entailing light DM particles. Previous studies have shown that light neutralino DM in the Minimal Supersymmetric Standard Model (MSSM), with parameters defined at the electroweak scale, is still viable when the low energy spectrum of the model features light sleptons, in which case, the relic density constraint can be fulfilled. In view of this, we have investigated the viability of light neutralinos as DM candidates in the MSSM, with parameters defined at the grand unification scale. We have analysed the optimal choices of non-universalities in the soft supersymmetry-breaking parameters for both, gauginos and scalars, in order to avoid the stringent experimental constraints. We show that light neutralinos, with a mass as low as 25 GeV, are viable in supergravity scenarios if the gaugino mass parameters at high energy are very non universal, while the scalar masses can remain of the same order. These scenarios typically predict a very small cross section of neutralinos off protons and neutrons, thereby being very challenging for direct detection experiments. However, a potential detection of smuons and selectrons at the LHC, together with a hypothetical discovery of a gamma-ray signal from neutralino annihilations in dwarf spheroidal galaxies could shed light on this kind of solutions. Finally, we have investigated the naturalness of these scenarios, taking into account all the potential sources of tuning. Besides the electroweak fine-tuning, we have found that the tuning to reproduce the correct DM relic abundance and that to match the measured Higgs mass can also be important when estimating the total degree of naturalness.

A tuning algorithm for model predictive controllers based on genetic algorithms and fuzzy decision making.

PubMed

van der Lee, J H; Svrcek, W Y; Young, B R

2008-01-01

Model Predictive Control is a valuable tool for the process control engineer in a wide variety of applications. Because of this the structure of an MPC can vary dramatically from application to application. There have been a number of works dedicated to MPC tuning for specific cases. Since MPCs can differ significantly, this means that these tuning methods become inapplicable and a trial and error tuning approach must be used. This can be quite time consuming and can result in non-optimum tuning. In an attempt to resolve this, a generalized automated tuning algorithm for MPCs was developed. This approach is numerically based and combines a genetic algorithm with multi-objective fuzzy decision-making. The key advantages to this approach are that genetic algorithms are not problem specific and only need to be adapted to account for the number and ranges of tuning parameters for a given MPC. As well, multi-objective fuzzy decision-making can handle qualitative statements of what optimum control is, in addition to being able to use multiple inputs to determine tuning parameters that best match the desired results. This is particularly useful for multi-input, multi-output (MIMO) cases where the definition of "optimum" control is subject to the opinion of the control engineer tuning the system. A case study will be presented in order to illustrate the use of the tuning algorithm. This will include how different definitions of "optimum" control can arise, and how they are accounted for in the multi-objective decision making algorithm. The resulting tuning parameters from each of the definition sets will be compared, and in doing so show that the tuning parameters vary in order to meet each definition of optimum control, thus showing the generalized automated tuning algorithm approach for tuning MPCs is feasible.

Multiple wavelength tunable surface-emitting laser arrays

NASA Astrophysics Data System (ADS)

Chang-Hasnain, Connie J.; Harbison, J. P.; Zah, Chung-En; Maeda, M. W.; Florez, L. T.; Stoffel, N. G.; Lee, Tien-Pei

1991-06-01

Techniques to achieve wavelength multiplexing and tuning capabilities in vertical-cavity surface-emitting lasers (VCSELs) are described, and experimental results are given. The authors obtained 140 unique, uniformly separated, single-mode wavelength emissions from a 7 x 20 VCSEL array. Large total wavelength span (about 430 A) and small wavelength separation (about 3 A) are obtained simultaneously with uncompromised laser performance. All 140 lasers have nearly the same threshold currents, voltages, and resistances. Wavelength tuning is obtained by using a three-mirror coupled-cavity configuration. The three-mirror laser is a two-terminal device and requires only one top contact. Discrete tuning with a range as large as 61 A is achieved with a small change in drive current of only 10.5 mA. The VCSEL output power variation is within 5 dB throughout the entire tuning range.

Calibration of Nu-Instruments Noblesse multicollector mass spectrometers for argon isotopic measurements using a newly developed reference gas

USGS Publications Warehouse

Coble, M.A.; Grove, M.; Calvert, A.T.

2011-01-01

The greatest challenge limiting 40Ar/39Ar multicollection measurements is the availability of appropriate standard gasses to intercalibrate detectors. In particular, use of zoom lens ion-optics to steer and focus ion beams into a fixed detector array (i.e., Nu Instruments Noblesse) makes intercalibration of multiple detectors challenging because different ion-optic tuning conditions are required for optimal peak shape and sensitivity at different mass stations. We have found that detector efficiency and mass discrimination are affected by changes in ion-optic tuning parameters. Reliance upon an atmospheric Ar standard to calibrate the Noblesse is problematic because there is no straightforward way to relate atmospheric 40Ar and 36Ar to measurements of 40Ar and 39Ar if they are measured on separate detectors. After exploring alternative calibration approaches, we have concluded that calibration of the Noblesse is best performed using exactly the same source, detector, and ion-optic tuning settings as those used in routine 40Ar/39Ar analysis. To accomplish this, we have developed synthetic reference gasses containing 40Ar, 39Ar and 38Ar produced by mixing gasses derived from neutron-irradiated sanidine with an enriched 38Ar spike. We present a new method for calibrating the Noblesse based on use of both atmospheric Ar and the synthetic reference gasses. By combining atmospheric Ar and synthetic reference gas in different ways, we can directly measure 40Ar/39Ar, 38Ar/39Ar, and 36Ar/39Ar correction factors over ratios that vary from 0.5 to 460. These correction factors are reproducible to better than ??0.5??? (2?? standard error) over intervals spanning ~24h but can vary systematically by ~4% over 2weeks of continuous use when electron multiplier settings are held constant. Monitoring this variation requires daily calibration of the instrument. Application of the calibration method to 40Ar/39Ar multicollection measurements of widely used sanidine reference materials ACs-2, FCs-2, and TCs-2 demonstrate that calculated 40Ar*/39ArK can be accurately corrected to yield model 40Ar/39Ar ages consistent with those reported by Earthtime 40Ar/39Ar laboratories. Replicate analyses of 8-12 single-crystal sanidine ages are reproduced to within 1-2??? (2?? standard error) under optimal analytical conditions. This calibration technique is applicable over a wide range of isotopic ratios and signal sizes. Finally, the reference gas has the added advantage of facilitating straightforward characterization of electron multiplier dead time over a wide dynamic range. ?? 2011 Elsevier B.V.

Measurement of the underlying event in jet events from 7 proton-proton collisions with the ATLAS detector

NASA Astrophysics Data System (ADS)

Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Gonzalez, B. Alvarez; Alviggi, M. G.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Ammosov, V. V.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Mayes, J. Backus; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borri, M.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, G.; Brown, J.; Renstrom, P. A. Bruckman de; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bryngemark, L.; Buanes, T.; Buat, Q.; Bucci, F.; Buchholz, P.; Buckingham, R. M.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bundock, A. C.; Burckhart, H.; Burdin, S.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, V.; Bussey, P.; Buszello, C. P.; Butler, B.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Byszewski, M.; Urbán, S. Cabrera; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Calvet, D.; Calvet, S.; Toro, R. Camacho; Camarda, S.; Cameron, D.; Caminada, L. M.; Armadans, R. Caminal; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cantero, J.; Cantrill, R.; Cao, T.; Garrido, M. D. M. Capeans; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Castaneda-Miranda, E.; Castelli, A.; Gimenez, V. Castillo; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Cattani, G.; Caughron, S.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chan, K.; Chang, P.; Chapleau, B.; Chapman, J. D.; Charfeddine, D.; Charlton, D. G.; Chau, C. C.; Barajas, C. A. Chavez; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; El Moursli, R. Cherkaoui; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiefari, G.; Childers, J. T.; Chilingarov, A.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Chouridou, S.; Chow, B. K. B.; Christidi, I. A.; Chromek-Burckhart, D.; Chu, M. L.; Chudoba, J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciocio, A.; Cirkovic, P.; Citron, Z. H.; Citterio, M.; Ciubancan, M.; Clark, A.; Clark, P. J.; Clarke, R. N.; Cleland, W.; Clemens, J. C.; Clement, B.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Coggeshall, J.; Cole, B.; Cole, S.; Colijn, A. P.; Collins-Tooth, C.; Collot, J.; Colombo, T.; Colon, G.; Compostella, G.; Muiño, P. Conde; Coniavitis, E.; Conidi, M. C.; Connell, S. H.; Connelly, I. A.; Consonni, S. M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cooper-Smith, N. J.; Copic, K.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Ortuzar, M. Crispin; Cristinziani, M.; Crosetti, G.; Cuciuc, C.-M.; Donszelmann, T. Cuhadar; Cummings, J.; Curatolo, M.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Daniells, A. C.; Hoffmann, M. Dano; Dao, V.; Darbo, G.; Darlea, G. L.; Darmora, S.; Dassoulas, J. A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davignon, O.; Davison, A. R.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Castro, S.; De Cecco, S.; de Graat, J.; De Groot, N.; de Jong, P.; De La Taille, C.; De la Torre, H.; De Lorenzi, F.; De Nooij, L.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; De Zorzi, G.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dechenaux, B.; Dedovich, D. V.; Degenhardt, J.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Deliot, F.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Dietzsch, T. A.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; do Vale, M. A. B.; Do Valle Wemans, A.; Doan, T. K. O.; Dobos, D.; Dobson, E.; Doglioni, C.; Doherty, T.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Dris, M.; Dubbert, J.; Dube, S.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Dudziak, F.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Yildiz, H. Duran; Düren, M.; Durglishvili, A.; Dwuznik, M.; Dyndal, M.; Ebke, J.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Engelmann, R.; Erdmann, J.; Ereditato, A.; Eriksson, D.; Ernis, G.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Favareto, A.; Fayard, L.; Federic, P.; Fedin, O. L.; Fedorko, W.; Fehling-Kaschek, M.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Perez, S. Fernandez; Fernando, W.; Ferrag, S.; Ferrando, J.; Ferrara, V.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. E.; Ferrer, A.; Ferrere, D.; Ferretti, C.; Parodi, A. Ferretto; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, J.; Fisher, M. J.; Fisher, W. C.; Fitzgerald, E. A.; Flechl, M.; Fleck, I.; Fleischmann, P.; Fleischmann, S.; Fletcher, G. T.; Fletcher, G.; Flick, T.; Floderus, A.; Castillo, L. R. Flores; Bustos, A. C. Florez; Flowerdew, M. J.; Formica, A.; Forti, A.; Fortin, D.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Franchino, S.; Francis, D.; Franklin, M.; Franz, S.; Fraternali, M.; French, S. T.; Friedrich, C.; Friedrich, F.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Torregrosa, E. Fullana; Fulsom, B. G.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gabrielli, A.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallo, V.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Gandrajula, R. P.; Gao, J.; Gao, Y. S.; Walls, F. M. Garay; Garberson, F.; García, C.; Navarro, J. E. García; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Gatti, C.; Gaudio, G.; Gaur, B.; Gauthier, L.; Gauzzi, P.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Ge, P.; Gecse, Z.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Gellerstedt, K.; Gemme, C.; Gemmell, A.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerbaudo, D.; Gershon, A.; Ghazlane, H.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giangiobbe, V.; Giannetti, P.; Gianotti, F.; Gibbard, B.; Gibson, S. M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giordano, R.; Giorgi, F. M.; Giraud, P. F.; Giugni, D.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkialas, I.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Glonti, G. L.; Goblirsch-Kolb, M.; Goddard, J. R.; Godfrey, J.; Godlewski, J.; Goeringer, C.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Fajardo, L. S. Gomez; Gonçalo, R.; Da Costa, J. Goncalves Pinto Firmino; Gonella, L.; de la Hoz, S. González; Parra, G. Gonzalez; Silva, M. L. Gonzalez; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Gouighri, M.; Goujdami, D.; Goulette, M. P.; Goussiou, A. G.; Goy, C.; Gozpinar, S.; Grabas, H. M. X.; Graber, L.; Grabowska-Bold, I.; Grafström, P.; Grahn, K.-J.; Gramling, J.; Gramstad, E.; Grancagnolo, F.; Grancagnolo, S.; Grassi, V.; Gratchev, V.; Gray, H. M.; Graziani, E.; Grebenyuk, O. G.; Greenwood, Z. D.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Griffiths, J.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grishkevich, Y. V.; Grivaz, J.-F.; Grohs, J. P.; Grohsjean, A.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Groth-Jensen, J.; Grout, Z. J.; Grybel, K.; Guan, L.; Guescini, F.; Guest, D.; Gueta, O.; Guicheney, C.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Gunther, J.; Guo, J.; Gupta, S.; Gutierrez, P.; Ortiz, N. G. Gutierrez; Gutschow, C.; Guttman, N.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Haddad, N.; Haefner, P.; Hageböck, S.; Hajduk, Z.; Hakobyan, H.; Haleem, M.; Hall, D.; Halladjian, G.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamer, M.; Hamilton, A.; Hamilton, S.; Hamnett, P. G.; Han, L.; Hanagaki, K.; Hanawa, K.; Hance, M.; Hanke, P.; Hansen, J. B.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Hard, A. S.; Harenberg, T.; Harkusha, S.; Harper, D.; Harrington, R. D.; Harris, O. M.; Harrison, P. F.; Hartjes, F.; Harvey, A.; Hasegawa, S.; Hasegawa, Y.; Hasib, A.; Hassani, S.; Haug, S.; Hauschild, M.; Hauser, R.; Havranek, M.; Hawkes, C. M.; Hawkings, R. J.; Hawkins, A. D.; Hayashi, T.; Hayden, D.; Hays, C. P.; Hayward, H. S.; Haywood, S. J.; Head, S. J.; Heck, T.; Hedberg, V.; Heelan, L.; Heim, S.; Heim, T.; Heinemann, B.; Heinrich, L.; Heisterkamp, S.; Hejbal, J.; Helary, L.; Heller, C.; Heller, M.; Hellman, S.; Hellmich, D.; Helsens, C.; Henderson, J.; Henderson, R. C. W.; Hengler, C.; Henrichs, A.; Correia, A. M. Henriques; Henrot-Versille, S.; Hensel, C.; Herbert, G. H.; Jiménez, Y. Hernández; Herrberg-Schubert, R.; Herten, G.; Hertenberger, R.; Hervas, L.; Hesketh, G. G.; Hessey, N. P.; Hickling, R.; Higón-Rodriguez, E.; Hill, J. C.; Hiller, K. H.; Hillert, S.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hirose, M.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoffman, J.; Hoffmann, D.; Hofmann, J. I.; Hohlfeld, M.; Holmes, T. R.; Hong, T. M.; van Huysduynen, L. Hooft; Hostachy, J.-Y.; Hou, S.; Hoummada, A.; Howard, J.; Howarth, J.; Hrabovsky, M.; Hristova, I.; Hrivnac, J.; Hryn'ova, T.; Hsu, P. J.; Hsu, S.-C.; Hu, D.; Hu, X.; Huang, Y.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Huhtinen, M.; Hülsing, T. A.; Hurwitz, M.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibragimov, I.; Iconomidou-Fayard, L.; Ideal, E.; Iengo, P.; Igonkina, O.; Iizawa, T.; Ikegami, Y.; Ikematsu, K.; Ikeno, M.; Iliadis, D.; Ilic, N.; Inamaru, Y.; Ince, T.; Ioannou, P.; Iodice, M.; Iordanidou, K.; Ippolito, V.; Quiles, A. Irles; Isaksson, C.; Ishino, M.; Ishitsuka, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Ponce, J. M. Iturbe; Ivashin, A. V.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jackson, B.; Jackson, J. N.; Jackson, M.; Jackson, P.; Jaekel, M. R.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakoubek, T.; Jakubek, J.; Jamin, D. O.; Jana, D. K.; Jansen, E.; Jansen, H.; Janssen, J.; Janus, M.; Jarlskog, G.; Javůrek, T.; Jeanty, L.; Jeng, G.-Y.; Jennens, D.; Jenni, P.; Jentzsch, J.; Jeske, C.; Jézéquel, S.; Ji, H.; Ji, W.; Jia, J.; Jiang, Y.; Belenguer, M. Jimenez; Jin, S.; Jinaru, A.; Jinnouchi, O.; Joergensen, M. D.; Johansson, K. E.; Johansson, P.; Johns, K. A.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, T. J.; Jongmanns, J.; Jorge, P. M.; Joshi, K. D.; Jovicevic, J.; Ju, X.; Jung, C. A.; Jungst, R. M.; Jussel, P.; Rozas, A. Juste; Kaci, M.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagan, M.; Kajomovitz, E.; Kama, S.; Kanaya, N.; Kaneda, M.; Kaneti, S.; Kanno, T.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kapliy, A.; Kar, D.; Karakostas, K.; Karastathis, N.; Karnevskiy, M.; Karpov, S. N.; Karthik, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kasieczka, G.; Kass, R. D.; Kastanas, A.; Kataoka, Y.; Katre, A.; Katzy, J.; Kaushik, V.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kazama, S.; Kazanin, V. F.; Kazarinov, M. Y.; Keeler, R.; Kehoe, R.; Keil, M.; Keller, J. S.; Keoshkerian, H.; Kepka, O.; Kerševan, B. P.; Kersten, S.; Kessoku, K.; Keung, J.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Khodinov, A.; Khomich, A.; Khoo, T. J.; Khoriauli, G.; Khoroshilov, A.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kim, H. Y.; Kim, H.; Kim, S. H.; Kimura, N.; Kind, O.; King, B. T.; King, M.; King, R. S. B.; King, S. B.; Kirk, J.; Kiryunin, A. E.; Kishimoto, T.; Kisielewska, D.; Kiss, F.; Kitamura, T.; Kittelmann, T.; Kiuchi, K.; Kladiva, E.; Klein, M.; Klein, U.; Kleinknecht, K.; Klimek, P.; Klimentov, A.; Klingenberg, R.; Klinger, J. A.; Klinkby, E. B.; Klioutchnikova, T.; Klok, P. F.; Kluge, E.-E.; Kluit, P.; Kluth, S.; Kneringer, E.; Knoops, E. B. F. G.; Knue, A.; Kobayashi, T.; Kobel, M.; Kocian, M.; Kodys, P.; Koevesarki, P.; Koffas, T.; Koffeman, E.; Kogan, L. A.; Kohlmann, S.; Kohout, Z.; Kohriki, T.; Koi, T.; Kolanoski, H.; Koletsou, I.; Koll, J.; Komar, A. A.; Komori, Y.; Kondo, T.; Köneke, K.; König, A. C.; König, S.; Kono, T.; Konoplich, R.; Konstantinidis, N.; Kopeliansky, R.; Koperny, S.; Köpke, L.; Kopp, A. K.; Korcyl, K.; Kordas, K.; Korn, A.; Korol, A. A.; Korolkov, I.; Korolkova, E. V.; Korotkov, V. A.; Kortner, O.; Kortner, S.; Kostyukhin, V. V.; Kotov, V. 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I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Cakir, I. Turk; Turra, R.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Uchida, K.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Uhlenbrock, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Urbaniec, D.; Urquijo, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Gallego, E. Valladolid; Vallecorsa, S.; Ferrer, J. A. Valls; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; Van Der Leeuw, R.; van der Ster, D.; Eldik, N. van; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veloso, F.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Perez, M. Villaplana; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Virzi, J.; Vitells, O.; Vivarelli, I.; Vaque, F. Vives; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; Radziewski, H. von; von Toerne, E.; Vorobel, V.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Anh, T. Vu; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Walsh, B.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, X.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Warsinsky, M.; Washbrook, A.; Wasicki, C.; Watanabe, I.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weigell, P.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wendland, D.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilkens, H. G.; Will, J. Z.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wittig, T.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wright, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xiao, M.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamada, M.; Yamaguchi, H.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, U. K.; Yang, Y.; Yanush, S.; Yao, L.; Yao, W.-M.; Yasu, Y.; Yatsenko, E.; Wong, K. H. Yau; Ye, J.; Ye, S.; Yen, A. L.; Yildirim, E.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zaytsev, A.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; della Porta, G. Zevi; Zhang, D.; Zhang, F.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, X.; Zhang, Z.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, L.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Zinonos, Z.; Ziolkowski, M.; Zitoun, R.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zutshi, V.; Zwalinski, L.

2014-08-01

Distributions sensitive to the underlying event in QCD jet events have been measured with the ATLAS detector at the LHC, based on of proton-proton collision data collected at a centre-of-mass energy of 7 . Charged-particle mean and densities of all-particle and charged-particle multiplicity and have been measured in regions azimuthally transverse to the hardest jet in each event. These are presented both as one-dimensional distributions and with their mean values as functions of the leading-jet transverse momentum from 20 to 800 . The correlation of charged-particle mean with charged-particle multiplicity is also studied, and the densities include the forward rapidity region; these features provide extra data constraints for Monte Carlo modelling of colour reconnection and beam-remnant effects respectively. For the first time, underlying event observables have been computed separately for inclusive jet and exclusive dijet event selections, allowing more detailed study of the interplay of multiple partonic scattering and QCD radiation contributions to the underlying event. Comparisons to the predictions of different Monte Carlo models show a need for further model tuning, but the standard approach is found to generally reproduce the features of the underlying event in both types of event selection.

Natural supersymmetry without light Higgsinos

DOE PAGES

Cohen, Timothy; Kearney, John; Luty, Markus A.

2015-04-08

In this study, we present a mechanism that allows a large Higgsino mass without large fine-tuning. The Higgs is a pseudo-Nambu-Goldstone boson (PNGB) of the global symmetry breaking pattern SO(5)→SO(4). Because of the PNGB nature of the light Higgs, the SO(5) invariant Higgsino mass does not directly contribute to the Higgs mass. Large couplings in the Higgs sector that spontaneously breaks SO(5) minimize the tuning, and are also motivated by the requirements of generating a sufficiently large Higgs quartic coupling and of maintaining a natural approximate global SO(5) symmetry. When these conditions are imposed, theories of this type predict heavymore » Higgsinos. This construction differs from composite Higgs models in that no new particles are introduced to form complete SO(5) multiplets involving the top quark—the stop is the only top partner. Compatibility with Higgs coupling measurements requires cancellations among contributions to the Higgs mass-squared parameter at the 10% level. An important implication of this construction is that the compressed region of stop and sbottom searches can still be natural.« less

Self-Tuning of Design Variables for Generalized Predictive Control

NASA Technical Reports Server (NTRS)

Lin, Chaung; Juang, Jer-Nan

2000-01-01

Three techniques are introduced to determine the order and control weighting for the design of a generalized predictive controller. These techniques are based on the application of fuzzy logic, genetic algorithms, and simulated annealing to conduct an optimal search on specific performance indexes or objective functions. Fuzzy logic is found to be feasible for real-time and on-line implementation due to its smooth and quick convergence. On the other hand, genetic algorithms and simulated annealing are applicable for initial estimation of the model order and control weighting, and final fine-tuning within a small region of the solution space, Several numerical simulations for a multiple-input and multiple-output system are given to illustrate the techniques developed in this paper.

Bi-directional vibration control of offshore wind turbines using a 3D pendulum tuned mass damper

NASA Astrophysics Data System (ADS)

Sun, C.; Jahangiri, V.

2018-05-01

Offshore wind turbines suffer from excessive bi-directional vibrations due to wind-wave misalignment and vortex induced vibrations. However, most of existing research focus on unidirectional vibration attenuation which is inadequate for real applications. The present paper proposes a three dimensional pendulum tuned mass damper (3d-PTMD) to mitigate the tower and nacelle dynamic response in the fore-aft and side-side directions. An analytical model of the wind turbine coupled with the 3d-PTMD is established wherein the interaction between the blades, the tower and the 3d-PTMD is modeled. Aerodynamic loading is computed using the Blade Element Momentum method where the Prandtls tip loss factor and the Glauert correction are considered. JONSWAP spectrum is adopted to generate wave data. Wave loading is computed using Morisons equation in collaboration with the strip theory. Via a numerical search approach, the design formula of the 3d-PTMD is obtained and examined on a National Renewable Energy Lab (NREL) monopile 5 MW baseline wind turbine model under misaligned wind, wave and seismic loading. Dual linear tuned mass dampers (TMDs) deployed in the fore-aft and side-side directions are utilized for comparison. It is found that the 3d-PTMD with a mass ratio of 2 % can improve the mitigation of the root mean square and peak response by around 10 % when compared with the dual linear TMDs in controlling the bi-directional vibration of the offshore wind turbines under misaligned wind, wave and seismic loading.

Tuned mass damping system for a pendulum in gravity and microgravity fields

NASA Astrophysics Data System (ADS)

Atour, Farah

2016-07-01

An electrodynamic tether is a simple idea, but one with an amazing number of uses. Electrodynamic tether is a long conductor wire that is attached to the satellite, which can act as a generator or motor, from its motion through the earth's magnetic field. And it has the potential to make space travel significantly cheaper. The lack of electrodynamic tether's widespread in common applications can be attributed to the variable Lorentz forces occuring on the tethers, which will cause them to oscillate and may go out of control, de-orbit the satellite and fall to Earth. A tuned mass damper system, for short refered as tilger, is suggested as damper of oscillations of tethers. A system composed of a tuned mass damper and a simple pendulum simulating the tether was therefore constructed. 350 sets of experimental trials were done on the system, while it was installed inside a drop tower capsule resting on the ground, in order to pick four optimum setup experiments that will undergo a series of microgravity experiments at the Bremen Drop Tower in Bremen, Germany. The GJU Bachelor Research students found that the oscillations of the simple pendulum will not be affected by the tilger during the free fall experiment, except if a feedback mechanism is installed between the simple pendulum and the tilger. In this case, the tilger will dampen the simple pendulum oscillations during free fall.

Decoding Reveals Plasticity in V3A as a Result of Motion Perceptual Learning

PubMed Central

Shibata, Kazuhisa; Chang, Li-Hung; Kim, Dongho; Náñez, José E.; Kamitani, Yukiyasu; Watanabe, Takeo; Sasaki, Yuka

2012-01-01

Visual perceptual learning (VPL) is defined as visual performance improvement after visual experiences. VPL is often highly specific for a visual feature presented during training. Such specificity is observed in behavioral tuning function changes with the highest improvement centered on the trained feature and was originally thought to be evidence for changes in the early visual system associated with VPL. However, results of neurophysiological studies have been highly controversial concerning whether the plasticity underlying VPL occurs within the visual cortex. The controversy may be partially due to the lack of observation of neural tuning function changes in multiple visual areas in association with VPL. Here using human subjects we systematically compared behavioral tuning function changes after global motion detection training with decoded tuning function changes for 8 visual areas using pattern classification analysis on functional magnetic resonance imaging (fMRI) signals. We found that the behavioral tuning function changes were extremely highly correlated to decoded tuning function changes only in V3A, which is known to be highly responsive to global motion with human subjects. We conclude that VPL of a global motion detection task involves plasticity in a specific visual cortical area. PMID:22952849

Natural Higgs mass in supersymmetry from nondecoupling effects.

PubMed

Lu, Xiaochuan; Murayama, Hitoshi; Ruderman, Joshua T; Tobioka, Kohsaku

2014-05-16

The Higgs mass implies fine-tuning for minimal theories of weak-scale supersymmetry (SUSY). Nondecoupling effects can boost the Higgs mass when new states interact with the Higgs boson, but new sources of SUSY breaking that accompany such extensions threaten naturalness. We show that two singlets with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. We explore the modified Higgs phenomenology of this scenario, which we call the "Dirac next-to-minimal supersymmetric standard model."

Adjudicating between face-coding models with individual-face fMRI responses

PubMed Central

Kriegeskorte, Nikolaus

2017-01-01

The perceptual representation of individual faces is often explained with reference to a norm-based face space. In such spaces, individuals are encoded as vectors where identity is primarily conveyed by direction and distinctiveness by eccentricity. Here we measured human fMRI responses and psychophysical similarity judgments of individual face exemplars, which were generated as realistic 3D animations using a computer-graphics model. We developed and evaluated multiple neurobiologically plausible computational models, each of which predicts a representational distance matrix and a regional-mean activation profile for 24 face stimuli. In the fusiform face area, a face-space coding model with sigmoidal ramp tuning provided a better account of the data than one based on exemplar tuning. However, an image-processing model with weighted banks of Gabor filters performed similarly. Accounting for the data required the inclusion of a measurement-level population averaging mechanism that approximates how fMRI voxels locally average distinct neuronal tunings. Our study demonstrates the importance of comparing multiple models and of modeling the measurement process in computational neuroimaging. PMID:28746335

Localized electrical fine tuning of passive microwave and radio frequency devices

DOEpatents

Findikoglu, Alp T.

2001-04-10

A method and apparatus for the localized electrical fine tuning of passive multiple element microwave or RF devices in which a nonlinear dielectric material is deposited onto predetermined areas of a substrate containing the device. An appropriate electrically conductive material is deposited over predetermined areas of the nonlinear dielectric and the signal line of the device for providing electrical contact with the nonlinear dielectric. Individual, adjustable bias voltages are applied to the electrically conductive material allowing localized electrical fine tuning of the devices. The method of the present invention can be applied to manufactured devices, or can be incorporated into the design of the devices so that it is applied at the time the devices are manufactured. The invention can be configured to provide localized fine tuning for devices including but not limited to coplanar waveguides, slotline devices, stripline devices, and microstrip devices.

Model-Based Self-Tuning Multiscale Method for Combustion Control

NASA Technical Reports Server (NTRS)

Le, Dzu, K.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

2006-01-01

A multi-scale representation of the combustor dynamics was used to create a self-tuning, scalable controller to suppress multiple instability modes in a liquid-fueled aero engine-derived combustor operating at engine-like conditions. Its self-tuning features designed to handle the uncertainties in the combustor dynamics and time-delays are essential for control performance and robustness. The controller was implemented to modulate a high-frequency fuel valve with feedback from dynamic pressure sensors. This scalable algorithm suppressed pressure oscillations of different instability modes by as much as 90 percent without the peak-splitting effect. The self-tuning logic guided the adjustment of controller parameters and converged quickly toward phase-lock for optimal suppression of the instabilities. The forced-response characteristics of the control model compare well with those of the test rig on both the frequency-domain and the time-domain.

Consistent analytic approach to the efficiency of collisional Penrose process

NASA Astrophysics Data System (ADS)

Harada, Tomohiro; Ogasawara, Kota; Miyamoto, Umpei

2016-07-01

We propose a consistent analytic approach to the efficiency of collisional Penrose process in the vicinity of a maximally rotating Kerr black hole. We focus on a collision with arbitrarily high center-of-mass energy, which occurs if either of the colliding particles has its angular momentum fine-tuned to the critical value to enter the horizon. We show that if the fine-tuned particle is ingoing on the collision, the upper limit of the efficiency is (2 +√{3 })(2 -√{2 })≃2.186 , while if the fine-tuned particle is bounced back before the collision, the upper limit is (2 +√{3 })2≃13.93 . Despite earlier claims, the former can be attained for inverse Compton scattering if the fine-tuned particle is massive and starts at rest at infinity, while the latter can be attained for various particle reactions, such as inverse Compton scattering and pair annihilation, if the fine-tuned particle is either massless or highly relativistic at infinity. We discuss the difference between the present and earlier analyses.

Reducing the spectral index in supernatural inflation

NASA Astrophysics Data System (ADS)

Lin, Chia-Min; Cheung, Kingman

2009-04-01

Supernatural inflation is an attractive model based on just a flat direction with soft supersymmetry breaking mass terms in the framework of supersymmetry. The beauty of the model is that it needs no fine-tuning. However, the prediction of the spectral index is ns≳1, in contrast to experimental data. In this paper, we discuss supernatural inflation with the spectral index reduced to ns=0.96 without any fine-tuning, considering the general feature that a flat direction is lifted by a nonrenormalizable term with an A-term.

Reducing variable frequency vibrations in a powertrain system with an adaptive tuned vibration absorber group

NASA Astrophysics Data System (ADS)

Gao, Pu; Xiang, Changle; Liu, Hui; Zhou, Han

2018-07-01

Based on a multiple degrees of freedom dynamic model of a vehicle powertrain system, natural vibration analyses and sensitivity analyses of the eigenvalues are performed to determine the key inertia for each natural vibration of a powertrain system. Then, the results are used to optimize the installation position of each adaptive tuned vibration absorber. According to the relationship between the variable frequency torque excitation and the natural vibration of a powertrain system, the entire vibration frequency band is divided into segments, and the auxiliary vibration absorber and dominant vibration absorber are determined for each sensitive frequency band. The optimum parameters of the auxiliary vibration absorber are calculated based on the optimal frequency ratio and the optimal damping ratio of the passive vibration absorber. The instantaneous change state of the natural vibrations of a powertrain system with adaptive tuned vibration absorbers is studied, and the optimized start and stop tuning frequencies of the adaptive tuned vibration absorber are obtained. These frequencies can be translated into the optimum parameters of the dominant vibration absorber. Finally, the optimal tuning scheme for the adaptive tuned vibration absorber group, which can be used to reduce the variable frequency vibrations of a powertrain system, is proposed, and corresponding numerical simulations are performed. The simulation time history signals are transformed into three-dimensional information related to time, frequency and vibration energy via the Hilbert-Huang transform (HHT). A comprehensive time-frequency analysis is then conducted to verify that the optimal tuning scheme for the adaptive tuned vibration absorber group can significantly reduce the variable frequency vibrations of a powertrain system.

Somatosensory impairment and its association with balance limitation in people with multiple sclerosis.

PubMed

Jamali, Akram; Sadeghi-Demneh, Ebrahim; Fereshtenajad, Niloufar; Hillier, Susan

2017-09-01

Somatosensory impairments are common in multiple sclerosis. However, little data are available to characterize the nature and frequency of these problems in people with multiple sclerosis. To investigate the frequency of somatosensory impairments and identify any association with balance limitations in people with multiple sclerosis. The design was a prospective cross-sectional study, involving 82 people with multiple sclerosis and 30 healthy controls. Tactile and proprioceptive sensory acuity were measured using the Rivermead Assessment of Somatosensory Performance. Vibration duration was assessed using a tuning fork. Duration for the Timed Up and Go Test and reaching distance of the Functional Reach Test were measured to assess balance limitations. The normative range of sensory modalities was defined using cut-off points in the healthy participants. The multivariate linear regression was used to identify the significant predictors of balance in people with multiple sclerosis. Proprioceptive impairments (66.7%) were more common than tactile (60.8%) and vibration impairments (44.9%). Somatosensory impairments were more frequent in the lower limb (78.2%) than the upper limb (64.1%). All sensory modalities were significantly associated with the Timed Up and Go and Functional Reach tests (p<0.05). The Timed Up and Go test was independently predicted by the severity of the neurological lesion, Body Mass Index, ataxia, and tactile sensation (R2=0.58), whereas the Functional Reach test was predicted by the severity of the neurological lesion, lower limb strength, and vibration sense (R2=0.49). Somatosensory impairments are very common in people with multiple sclerosis. These impairments are independent predictors of balance limitation. Copyright © 2017 Elsevier B.V. All rights reserved.

A Novel Controller Design for the Next Generation Space Electrostatic Accelerometer Based on Disturbance Observation and Rejection.

PubMed

Li, Hongyin; Bai, Yanzheng; Hu, Ming; Luo, Yingxin; Zhou, Zebing

2016-12-23

The state-of-the-art accelerometer technology has been widely applied in space missions. The performance of the next generation accelerometer in future geodesic satellites is pushed to 8 × 10 - 13 m / s 2 / H z 1 / 2 , which is close to the hardware fundamental limit. According to the instrument noise budget, the geodesic test mass must be kept in the center of the accelerometer within the bounds of 56 pm / Hz 1 / 2 by the feedback controller. The unprecedented control requirements and necessity for the integration of calibration functions calls for a new type of control scheme with more flexibility and robustness. A novel digital controller design for the next generation electrostatic accelerometers based on disturbance observation and rejection with the well-studied Embedded Model Control (EMC) methodology is presented. The parameters are optimized automatically using a non-smooth optimization toolbox and setting a weighted H-infinity norm as the target. The precise frequency performance requirement of the accelerometer is well met during the batch auto-tuning, and a series of controllers for multiple working modes is generated. Simulation results show that the novel controller could obtain not only better disturbance rejection performance than the traditional Proportional Integral Derivative (PID) controllers, but also new instrument functions, including: easier tuning procedure, separation of measurement and control bandwidth and smooth control parameter switching.

A Novel Controller Design for the Next Generation Space Electrostatic Accelerometer Based on Disturbance Observation and Rejection

PubMed Central

Li, Hongyin; Bai, Yanzheng; Hu, Ming; Luo, Yingxin; Zhou, Zebing

2016-01-01

The state-of-the-art accelerometer technology has been widely applied in space missions. The performance of the next generation accelerometer in future geodesic satellites is pushed to 8×10−13m/s2/Hz1/2, which is close to the hardware fundamental limit. According to the instrument noise budget, the geodesic test mass must be kept in the center of the accelerometer within the bounds of 56 pm/Hz1/2 by the feedback controller. The unprecedented control requirements and necessity for the integration of calibration functions calls for a new type of control scheme with more flexibility and robustness. A novel digital controller design for the next generation electrostatic accelerometers based on disturbance observation and rejection with the well-studied Embedded Model Control (EMC) methodology is presented. The parameters are optimized automatically using a non-smooth optimization toolbox and setting a weighted H-infinity norm as the target. The precise frequency performance requirement of the accelerometer is well met during the batch auto-tuning, and a series of controllers for multiple working modes is generated. Simulation results show that the novel controller could obtain not only better disturbance rejection performance than the traditional Proportional Integral Derivative (PID) controllers, but also new instrument functions, including: easier tuning procedure, separation of measurement and control bandwidth and smooth control parameter switching. PMID:28025534

Properties and Applications of Varistor-Transistor Hybrid Devices

NASA Astrophysics Data System (ADS)

Pandey, R. K.; Stapleton, William A.; Sutanto, Ivan; Scantlin, Amanda A.; Lin, Sidney

2014-05-01

The nonlinear current-voltage characteristics of a varistor device are modified with the help of external agents, resulting in tuned varistor-transistor hybrid devices with multiple applications. The substrate used to produce these hybrid devices belongs to the modified iron titanate family with chemical formula 0.55FeTiO3·0.45Fe2O3 (IHC45), which is a prominent member of the ilmenite-hematite solid-solution series. It is a wide-bandgap magnetic oxide semiconductor. Electrical resistivity and Seebeck coefficient measurements from room temperature to about 700°C confirm that it retains its p-type nature for the entire temperature range. The direct-current (DC) and alternating-current (AC) properties of these hybrid devices are discussed and their applications identified. It is shown here that such varistor embedded ceramic transistors with many interesting properties and applications can be mass produced using incredibly simple structures. The tuned varistors by themselves can be used for current amplification and band-pass filters. The transistors on the other hand could be used to produce sensors, voltage-controlled current sources, current-controlled voltage sources, signal amplifiers, and low-band-pass filters. We believe that these devices could be suitable for a number of applications in consumer and defense electronics, high-temperature and space electronics, bioelectronics, and possibly also for electronics specific to handheld devices.

Automatic recognition of 3D GGO CT imaging signs through the fusion of hybrid resampling and layer-wise fine-tuning CNNs.

PubMed

Han, Guanghui; Liu, Xiabi; Zheng, Guangyuan; Wang, Murong; Huang, Shan

2018-06-06

Ground-glass opacity (GGO) is a common CT imaging sign on high-resolution CT, which means the lesion is more likely to be malignant compared to common solid lung nodules. The automatic recognition of GGO CT imaging signs is of great importance for early diagnosis and possible cure of lung cancers. The present GGO recognition methods employ traditional low-level features and system performance improves slowly. Considering the high-performance of CNN model in computer vision field, we proposed an automatic recognition method of 3D GGO CT imaging signs through the fusion of hybrid resampling and layer-wise fine-tuning CNN models in this paper. Our hybrid resampling is performed on multi-views and multi-receptive fields, which reduces the risk of missing small or large GGOs by adopting representative sampling panels and processing GGOs with multiple scales simultaneously. The layer-wise fine-tuning strategy has the ability to obtain the optimal fine-tuning model. Multi-CNN models fusion strategy obtains better performance than any single trained model. We evaluated our method on the GGO nodule samples in publicly available LIDC-IDRI dataset of chest CT scans. The experimental results show that our method yields excellent results with 96.64% sensitivity, 71.43% specificity, and 0.83 F1 score. Our method is a promising approach to apply deep learning method to computer-aided analysis of specific CT imaging signs with insufficient labeled images. Graphical abstract We proposed an automatic recognition method of 3D GGO CT imaging signs through the fusion of hybrid resampling and layer-wise fine-tuning CNN models in this paper. Our hybrid resampling reduces the risk of missing small or large GGOs by adopting representative sampling panels and processing GGOs with multiple scales simultaneously. The layer-wise fine-tuning strategy has ability to obtain the optimal fine-tuning model. Our method is a promising approach to apply deep learning method to computer-aided analysis of specific CT imaging signs with insufficient labeled images.

Temporal properties of responses to sound in the ventral nucleus of the lateral lemniscus.

PubMed

Recio-Spinoso, Alberto; Joris, Philip X

2014-02-01

Besides the rapid fluctuations in pressure that constitute the "fine structure" of a sound stimulus, slower fluctuations in the sound's envelope represent an important temporal feature. At various stages in the auditory system, neurons exhibit tuning to envelope frequency and have been described as modulation filters. We examine such tuning in the ventral nucleus of the lateral lemniscus (VNLL) of the pentobarbital-anesthetized cat. The VNLL is a large but poorly accessible auditory structure that provides a massive inhibitory input to the inferior colliculus. We test whether envelope filtering effectively applies to the envelope spectrum when multiple envelope components are simultaneously present. We find two broad classes of response with often complementary properties. The firing rate of onset neurons is tuned to a band of modulation frequencies, over which they also synchronize strongly to the envelope waveform. Although most sustained neurons show little firing rate dependence on modulation frequency, some of them are weakly tuned. The latter neurons are usually band-pass or low-pass tuned in synchronization, and a reverse-correlation approach demonstrates that their modulation tuning is preserved to nonperiodic, noisy envelope modulations of a tonal carrier. Modulation tuning to this type of stimulus is weaker for onset neurons. In response to broadband noise, sustained and onset neurons tend to filter out envelope components over a frequency range consistent with their modulation tuning to periodically modulated tones. The results support a role for VNLL in providing temporal reference signals to the auditory midbrain.

Multiplicative mixing of object identity and image attributes in single inferior temporal neurons.

PubMed

Ratan Murty, N Apurva; Arun, S P

2018-04-03

Object recognition is challenging because the same object can produce vastly different images, mixing signals related to its identity with signals due to its image attributes, such as size, position, rotation, etc. Previous studies have shown that both signals are present in high-level visual areas, but precisely how they are combined has remained unclear. One possibility is that neurons might encode identity and attribute signals multiplicatively so that each can be efficiently decoded without interference from the other. Here, we show that, in high-level visual cortex, responses of single neurons can be explained better as a product rather than a sum of tuning for object identity and tuning for image attributes. This subtle effect in single neurons produced substantially better population decoding of object identity and image attributes in the neural population as a whole. This property was absent both in low-level vision models and in deep neural networks. It was also unique to invariances: when tested with two-part objects, neural responses were explained better as a sum than as a product of part tuning. Taken together, our results indicate that signals requiring separate decoding, such as object identity and image attributes, are combined multiplicatively in IT neurons, whereas signals that require integration (such as parts in an object) are combined additively. Copyright © 2018 the Author(s). Published by PNAS.

Multiple components of surround modulation in primary visual cortex: multiple neural circuits with multiple functions?

PubMed Central

Nurminen, Lauri; Angelucci, Alessandra

2014-01-01

The responses of neurons in primary visual cortex (V1) to stimulation of their receptive field (RF) are modulated by stimuli in the RF surround. This modulation is suppressive when the stimuli in the RF and surround are of similar orientation, but less suppressive or facilitatory when they are cross-oriented. Similarly, in human vision surround stimuli selectively suppress the perceived contrast of a central stimulus. Although the properties of surround modulation have been thoroughly characterized in many species, cortical areas and sensory modalities, its role in perception remains unknown. Here we argue that surround modulation in V1 consists of multiple components having different spatio-temporal and tuning properties, generated by different neural circuits and serving different visual functions. One component arises from LGN afferents, is fast, untuned for orientation, and spatially restricted to the surround region nearest to the RF (the near-surround); its function is to normalize V1 cell responses to local contrast. Intra-V1 horizontal connections contribute a slower, narrowly orientation-tuned component to near-surround modulation, whose function is to increase the coding efficiency of natural images in manner that leads to the extraction of object boundaries. The third component is generated by topdown feedback connections to V1, is fast, broadly orientation-tuned, and extends into the far-surround; its function is to enhance the salience of behaviorally relevant visual features. Far- and near-surround modulation, thus, act as parallel mechanisms: the former quickly detects and guides saccades/attention to salient visual scene locations, the latter segments object boundaries in the scene. PMID:25204770

Unification and new particles at the LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arkani-Hamed, Nima; D’Agnolo, Raffaele Tito; Low, Matthew

Precision gauge coupling uni cation is one of the primary quantitative successes of low energy or split supersymmetry. Preserving this success puts severe restrictions on possible matter and gauge sectors that might appear at collider-accessible energies. In this study we enumerate new gauge sectors which are compatible with uni cation, consisting of horizontal gauge groups acting on vector-like matter charged under the Standard Model. Interestingly, almost all of these theories are in the supersymmetric conformal window at high energies and con ne quickly after the superpartners are decoupled. For a range of scalar masses compatible with both moderately tuned andmore » minimally split supersymmetry, the con ning dynamics happen at the multi-TeV scale, leading to a spectrum of multiple spin-0 and spin-1 resonances accessible to the LHC, with unusual quantum numbers and striking decay patterns.« less

Unification and new particles at the LHC

DOE PAGES

Arkani-Hamed, Nima; D’Agnolo, Raffaele Tito; Low, Matthew; ...

2016-11-14

Precision gauge coupling uni cation is one of the primary quantitative successes of low energy or split supersymmetry. Preserving this success puts severe restrictions on possible matter and gauge sectors that might appear at collider-accessible energies. In this study we enumerate new gauge sectors which are compatible with uni cation, consisting of horizontal gauge groups acting on vector-like matter charged under the Standard Model. Interestingly, almost all of these theories are in the supersymmetric conformal window at high energies and con ne quickly after the superpartners are decoupled. For a range of scalar masses compatible with both moderately tuned andmore » minimally split supersymmetry, the con ning dynamics happen at the multi-TeV scale, leading to a spectrum of multiple spin-0 and spin-1 resonances accessible to the LHC, with unusual quantum numbers and striking decay patterns.« less

What has driven the evolution of multiple cone classes in visual systems: object contrast enhancement or light flicker elimination?

PubMed

Sabbah, Shai; Hawryshyn, Craig W

2013-07-04

Two competing theories have been advanced to explain the evolution of multiple cone classes in vertebrate eyes. These two theories have important, but different, implications for our understanding of the design and tuning of vertebrate visual systems. The 'contrast theory' proposes that multiple cone classes evolved in shallow-water fish to maximize the visual contrast of objects against diverse backgrounds. The competing 'flicker theory' states that multiple cone classes evolved to eliminate the light flicker inherent in shallow-water environments through antagonistic neural interactions, thereby enhancing object detection. However, the selective pressures that have driven the evolution of multiple cone classes remain largely obscure. We show that two critical assumptions of the flicker theory are violated. We found that the amplitude and temporal frequency of flicker vary over the visible spectrum, precluding its cancellation by simple antagonistic interactions between the output signals of cones. Moreover, we found that the temporal frequency of flicker matches the frequency where sensitivity is maximal in a wide range of fish taxa, suggesting that the flicker may actually enhance the detection of objects. Finally, using modeling of the chromatic contrast between fish pattern and background under flickering illumination, we found that the spectral sensitivity of cones in a cichlid focal species is optimally tuned to maximize the visual contrast between fish pattern and background, instead of to produce a flicker-free visual signal. The violation of its two critical assumptions substantially undermines support for the flicker theory as originally formulated. While this alone does not support the contrast theory, comparison of the contrast and flicker theories revealed that the visual system of our focal species was tuned as predicted by the contrast theory rather than by the flicker theory (or by some combination of the two). Thus, these findings challenge key assumptions of the flicker theory, leaving the contrast theory as the most parsimonious and tenable account of the evolution of multiple cone classes.

Radiative natural supersymmetry: Reconciling electroweak fine-tuning and the Higgs boson mass

NASA Astrophysics Data System (ADS)

Baer, Howard; Barger, Vernon; Huang, Peisi; Mickelson, Dan; Mustafayev, Azar; Tata, Xerxes

2013-06-01

Models of natural supersymmetry seek to solve the little hierarchy problem by positing a spectrum of light Higgsinos ≲200-300GeV and light top squarks ≲600GeV along with very heavy squarks and TeV-scale gluinos. Such models have low electroweak fine-tuning and satisfy the LHC constraints. However, in the context of the minimal supersymmetric standard model, they predict too low a value of mh, are frequently in conflict with the measured b→sγ branching fraction, and the relic density of thermally produced Higgsino-like weakly interacting massive particles (WIMPs) falls well below dark matter measurements. We propose a framework dubbed radiative natural supersymmetry (RNS), which can be realized within the minimal supersymmetric standard model (avoiding the addition of extra exotic matter) and which maintains features such as gauge coupling unification and radiative electroweak symmetry breaking. The RNS model can be generated from supersymmetry (SUSY) grand unified theory type models with nonuniversal Higgs masses. Allowing for high-scale soft SUSY breaking Higgs mass mHu>m0 leads to automatic cancellations during renormalization group running and to radiatively-induced low fine-tuning at the electroweak scale. Coupled with large mixing in the top-squark sector, RNS allows for fine-tuning at the 3%-10% level with TeV-scale top squarks and a 125 GeV light Higgs scalar h. The model allows for at least a partial solution to the SUSY flavor, CP, and gravitino problems since first-/second-generation scalars (and the gravitino) may exist in the 10-30 TeV regime. We outline some possible signatures for RNS at the LHC, such as the appearance of low invariant mass opposite-sign isolated dileptons from gluino cascade decays. The smoking gun signature for RNS is the appearance of light Higgsinos at a linear e+e- collider. If the strong CP problem is solved by the Peccei-Quinn mechanism, then RNS naturally accommodates mixed axion-Higgsino cold dark matter, where the light Higgsino-like WIMPs—which in this case make up only a fraction of the measured relic abundance—should be detectable at upcoming WIMP detectors.

A multi-frequency fatigue testing method for wind turbine rotor blades

NASA Astrophysics Data System (ADS)

Eder, M. A.; Belloni, F.; Tesauro, A.; Hanis, T.

2017-02-01

Rotor blades are among the most delicate components of modern wind turbines. Reliability is a crucial aspect, since blades shall ideally remain free of failure under ultra-high cycle loading conditions throughout their designated lifetime of 20-25 years. Full-scale blade tests are the most accurate means to experimentally simulate damage evolution under operating conditions, and are therefore used to demonstrate that a blade type fulfils the reliability requirements to an acceptable degree of confidence. The state-of-the-art testing method for rotor blades in industry is based on resonance excitation where typically a rotating mass excites the blade close to its first natural frequency. During operation the blade response due to external forcing is governed by a weighted combination of its eigenmodes. Current test methodologies which only utilise the lowest eigenfrequency induce a fictitious damage where additional tuning masses are required to recover the desired damage distribution. Even with the commonly adopted amplitude upscaling technique fatigue tests remain a time-consuming and costly endeavour. The application of tuning masses increases the complexity of the problem by lowering the natural frequency of the blade and therefore increasing the testing time. The novel method presented in this paper aims at shortening the duration of the state-of-the-art fatigue testing method by simultaneously exciting the blade with a combination of two or more eigenfrequencies. Taking advantage of the different shapes of the excited eigenmodes, the actual spatial damage distribution can be more realistically simulated in the tests by tuning the excitation force amplitudes rather than adding tuning masses. This implies that in portions of the blade the lowest mode is governing the damage whereas in others higher modes contribute more significantly due to their higher cycle count. A numerical feasibility study based on a publicly available large utility rotor blade is used to demonstrate the ability of the proposed approach to outperform the state-of-the-art testing method without compromising fatigue test requirements. It will be shown that the novel method shortens the testing time and renders the damage evolution with a higher degree of fidelity.

Analysis of tuning methods in semiconductor frequency-selective surfaces

NASA Astrophysics Data System (ADS)

Shemelya, Corey; Palm, Dominic; Fip, Tassilo; Rahm, Marco

2017-02-01

Advanced technology, such as sensing and communication equipment, has recently begun to combine optically sensitive nano-scale structures with customizable semiconductor material systems. Included within this broad field of study is the aptly named frequency-selective surface; which is unique in that it can be artificially designed to produce a specific electromagnetic or optical response. With the inherent utility of a frequency-selective surface, there has been an increased interest in the area of dynamic frequency-selective surfaces, which can be altered through optical or electrical tuning. This area has had exciting break throughs as tuning methods have evolved; however, these methods are typically energy intensive (optical tuning) or have met with limited success (electrical tuning). As such, this work investigates multiple structures and processes which implement semiconductor electrical biasing and/or optical tuning. Within this study are surfaces ranging from transmission meta-structures to metamaterial surface-waves and the associated coupling schemes. This work shows the utility of each design, while highlighting potential methods for optimizing dynamic meta-surfaces. As an added constraint, the structures were also designed to operate in unison with a state-of-the-art Ti:Sapphire Spitfire Ace and Spitfire Ace PA dual system (12 Watt) with pulse front matching THz generation and an EOS detection system. Additionally, the Ti:Sapphire laser system would provide the means for optical tunablity, while electrical tuning can be obtained through external power supplies.

Central genes, pathways and modules that regulate bone mass.

PubMed

Quiros-Gonzalez, Isabel; Yadav, Vijay K

2014-11-01

Bones are structures that give the shape and defined features to vertebrates, protect several soft organs and perform multiple endocrine influences on other organs. To achieve these functions bones are first modeled early during life and then constantly remodeled throughout life. The process of bone (re)modeling happens simultaneously at multitude of locations in the skeleton and ensures that vertebrates have a mechanically strong yet a flexible skeleton to the most part of their life. Given the extent of its occurrence in the body, bone remodeling is a highly energy demanding process and is co-ordinated with other physiological processes as diverse as energy metabolism, sleep-wake cycle and reproduction. Neuronal circuits in the brain play a very important role in the coordination of bone remodeling with other organ system functions, and perform this function in sync with environmental and peripheral hormonal cues. In this review, we will focus on the roles of hormonal signals and neural circuits that originate in, or impinge on, the brain in the regulation of bone mass. We will provide herein an updated view of how advances in molecular genetics have refined the neural circuits involved in the regulation of bone mass, from the whole brain level to the specific neuronal populations and their neurotransmitters. This will help to understand the mechanisms whereby vertebrate brain regulates bone mass by fine-tuning metabolic signals that originate in the brain or elsewhere in the body. Copyright © 2014 Elsevier Inc. All rights reserved.

Optical behaviors of flexible photonic films via the developed multiple UV-exposed fabrications.

PubMed

Chien, Chih-Chieh; Liu, Jui-Hsiang

2014-07-01

Recently, extensive investigations are carried out on design of highly controlled architecture and morphology by polymerizing the monomers doped in well-defined liquid crystalline materials, followed by removal of the template liquid crystal molecules. In this communication, a photonic structure used as a new photonic bandgap (PBG) material is developed by imprinting helical structures on polymer matrices through multiple photocrosslinking processes in an induced chiral nematic mesophase using flexible polyethylene terephthalate (PET) films as substrates. The tuning properties of the reflection band of the imprinted cell are achieved using an uniaxial thermo-stretching equipment. Furthermore, refilling of isotropic materials into the imprinted cells tune the reflection light wavelength leads to the change of color. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wideband Reconfigurable Harmonically Tuned GaN SSPA for Cognitive Radios

NASA Technical Reports Server (NTRS)

Waldstein, Seth W.; Barbosa Kortright, Miguel A.; Simons, Rainee N.

2017-01-01

The paper presents the architecture of a wideband reconfigurable harmonically-tuned Gallium Nitrate (GaN) Solid State Power Amplifier (SSPA) for cognitive radios. When interfaced with the physical layer of a cognitive communication system, this amplifier topology offers broadband high efficiency through the use of multiple tuned input/output matching networks. This feature enables the cognitive radio to reconfigure the operating frequency without sacrificing efficiency. This paper additionally presents as a proof-of-concept the design, fabrication, and test results for a GaN inverse class-F type amplifier operating at X-band (8.4 GHz) that achieves a maximum output power of 5.14-W, Power Added Efficiency (PAE) of 38.6, and Drain Efficiency (DE) of 48.9 under continuous wave (CW) operation.

Semi-active control of monopile offshore wind turbines under multi-hazards

NASA Astrophysics Data System (ADS)

Sun, C.

2018-01-01

The present paper studies the control of monopile offshore wind turbines subjected to multi-hazards consisting of wind, wave and earthquake. A Semi-active tuned mass damper (STMD) with tunable natural frequency and damping ratio is introduced to control the dynamic response. A new fully coupled analytical model of the monopile offshore wind turbine with an STMD is established. The aerodynamic, hydrodynamic and seismic loading models are derived. Soil effects and damage are considered. The National Renewable Energy Lab monopile 5 MW baseline wind turbine model is employed to examine the performance of the STMD. A passive tuned mass damper (TMD) is utilized for comparison. Through numerical simulation, it is found that before damage occurs, the wind and wave induced response is more dominant than the earthquake induced response. With damage presence in the tower and the foundation, the nacelle and the tower response is increased dramatically and the natural frequency is decreased considerably. As a result, the passive TMD with fixed parameters becomes off-tuned and loses its effectiveness. In comparison, the STMD retuned in real-time demonstrates consistent effectiveness in controlling the dynamic response of the monopile offshore wind turbines under multi-hazards and damage with a smaller stroke.

Surface tuning laser desorption/ionization mass spectrometry (STLDI-MS) for the analysis of small molecules using quantum dots.

PubMed

Abdelhamid, Hani Nasser; Chen, Zhen-Yu; Wu, Hui-Fen

2017-08-01

In most applications of quantum dots (QDs) for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS), one side of QDs is supported by a solid substrate (stainless - steel plate), whereas the other side is in contact with the target analytes. Therefore, the surface capping agent of QDs is a key parameter for laser desorption/ionization mass spectrometry (LDI-MS). Cadmium telluride quantum dots (CdTe QDs) modified with different capping agents are synthesized, characterized, and applied for surface tuning laser desorption/ionization mass spectrometry (STLDI-MS). Data shows that CdTe quantum dot modified cysteine (cys@CdTe QDs) has an absorption that matches with the wavelength of the N 2 laser (337 nm). The synergistic effect of large surface area and absorption of the laser irradiation of cys@CdTe QDs enhances the LDI-MS process for small - molecule analysis, including α-, β-, and γ-cyclodextrin, gramicidin D, perylene, pyrene, and triphenylphosphine. Cys@CdTe QDs are also applied using Al foils as substrates. Aluminum foil combined with cys@CdTe QDs enhances the ionization efficiency and is cheap compared to traditional matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with a stainless - steel plate.

Critical gravitational collapse with angular momentum. II. Soft equations of state

NASA Astrophysics Data System (ADS)

Gundlach, Carsten; Baumgarte, Thomas W.

2018-03-01

We study critical phenomena in the collapse of rotating ultrarelativistic perfect fluids, in which the pressure P is related to the total energy density ρ by P =κ ρ , where κ is a constant. We generalize earlier results for radiation fluids with κ =1 /3 to other values of κ , focusing on κ <1 /9 . For 1 /9 <κ ≲0.49 , the critical solution has only one unstable, growing mode, which is spherically symmetric. For supercritical data it controls the black-hole mass, while for subcritical data it controls the maximum density. For κ <1 /9 , an additional axial l =1 mode becomes unstable. This controls either the black-hole angular momentum, or the maximum angular velocity. In theory, the additional unstable l =1 mode changes the nature of the black-hole threshold completely: at sufficiently large initial rotation rates Ω and sufficient fine-tuning of the initial data to the black-hole threshold we expect to observe nontrivial universal scaling functions (familiar from critical phase transitions in thermodynamics) governing the black-hole mass and angular momentum, and, with further fine-tuning, eventually a finite black-hole mass almost everywhere on the threshold. In practice, however, the second unstable mode grows so slowly that we do not observe this breakdown of scaling at the level of fine-tuning we can achieve, nor systematic deviations from the leading-order power-law scalings of the black-hole mass. We do see systematic effects in the black-hole angular momentum, but it is not clear yet if these are due to the predicted nontrivial scaling functions, or to nonlinear effects at sufficiently large initial angular momentum (which we do not account for in our theoretical model).

Utility of Thin-Film Solar Cells on Flexible Substrates for Space Power

NASA Technical Reports Server (NTRS)

Dickman, J. E.; Hepp, A. F.; Morel, D. L.; Ferekides, C. S.; Tuttle, J. R.; Hoffman, D. J.; Dhere, N. G.

2004-01-01

The thin-film solar cell program at NASA GRC is developing solar cell technologies for space applications which address two critical metrics: specific power (power per unit mass) and launch stowed volume. To be competitive for many space applications, an array using thin film solar cells must significantly increase specific power while reducing stowed volume when compared to the present baseline technology utilizing crystalline solar cells. The NASA GRC program is developing two approaches. Since the vast majority of the mass of a thin film solar cell is in the substrate, a thin film solar cell on a very lightweight flexible substrate (polymer or metal films) is being developed as the first approach. The second approach is the development of multijunction thin film solar cells. Total cell efficiency can be increased by stacking multiple cells having bandgaps tuned to convert the spectrum passing through the upper cells to the lower cells. Once developed, the two approaches will be merged to yield a multijunction, thin film solar cell on a very lightweight, flexible substrate. The ultimate utility of such solar cells in space require the development of monolithic interconnections, lightweight array structures, and ultra-lightweight support and deployment techniques.

MicroRNA-8 promotes robust motor axon targeting by coordinate regulation of cell adhesion molecules during synapse development.

PubMed

Lu, Cecilia S; Zhai, Bo; Mauss, Alex; Landgraf, Matthias; Gygi, Stephen; Van Vactor, David

2014-09-26

Neuronal connectivity and specificity rely upon precise coordinated deployment of multiple cell-surface and secreted molecules. MicroRNAs have tremendous potential for shaping neural circuitry by fine-tuning the spatio-temporal expression of key synaptic effector molecules. The highly conserved microRNA miR-8 is required during late stages of neuromuscular synapse development in Drosophila. However, its role in initial synapse formation was previously unknown. Detailed analysis of synaptogenesis in this system now reveals that miR-8 is required at the earliest stages of muscle target contact by RP3 motor axons. We find that the localization of multiple synaptic cell adhesion molecules (CAMs) is dependent on the expression of miR-8, suggesting that miR-8 regulates the initial assembly of synaptic sites. Using stable isotope labelling in vivo and comparative mass spectrometry, we find that miR-8 is required for normal expression of multiple proteins, including the CAMs Fasciclin III (FasIII) and Neuroglian (Nrg). Genetic analysis suggests that Nrg and FasIII collaborate downstream of miR-8 to promote accurate target recognition. Unlike the function of miR-8 at mature larval neuromuscular junctions, at the embryonic stage we find that miR-8 controls key effectors on both sides of the synapse. MiR-8 controls multiple stages of synapse formation through the coordinate regulation of both pre- and postsynaptic cell adhesion proteins.

MicroRNA-8 promotes robust motor axon targeting by coordinate regulation of cell adhesion molecules during synapse development

PubMed Central

Lu, Cecilia S.; Zhai, Bo; Mauss, Alex; Landgraf, Matthias; Gygi, Stephen; Van Vactor, David

2014-01-01

Neuronal connectivity and specificity rely upon precise coordinated deployment of multiple cell-surface and secreted molecules. MicroRNAs have tremendous potential for shaping neural circuitry by fine-tuning the spatio-temporal expression of key synaptic effector molecules. The highly conserved microRNA miR-8 is required during late stages of neuromuscular synapse development in Drosophila. However, its role in initial synapse formation was previously unknown. Detailed analysis of synaptogenesis in this system now reveals that miR-8 is required at the earliest stages of muscle target contact by RP3 motor axons. We find that the localization of multiple synaptic cell adhesion molecules (CAMs) is dependent on the expression of miR-8, suggesting that miR-8 regulates the initial assembly of synaptic sites. Using stable isotope labelling in vivo and comparative mass spectrometry, we find that miR-8 is required for normal expression of multiple proteins, including the CAMs Fasciclin III (FasIII) and Neuroglian (Nrg). Genetic analysis suggests that Nrg and FasIII collaborate downstream of miR-8 to promote accurate target recognition. Unlike the function of miR-8 at mature larval neuromuscular junctions, at the embryonic stage we find that miR-8 controls key effectors on both sides of the synapse. MiR-8 controls multiple stages of synapse formation through the coordinate regulation of both pre- and postsynaptic cell adhesion proteins. PMID:25135978

Tuning into YouTube in the Classroom: Improving Assessment Scores through Social Media

ERIC Educational Resources Information Center

Younger, Dylinda W.; Duncan, Jan E.; Hart, LaToya M.

2013-01-01

Despite the consistent tendencies of higher-education faculty to utilize single testing measures (i.e. essay or multiple choice), education research indicates effective assessment of student learning must incorporate multiple formats. With the surge of online courses, programs, and universities in the last 20 years, there is an increasing need to…

Use of external cavity quantum cascade laser compliance voltage in real-time trace gas sensing of multiple chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Mark C.; Taubman, Matthew S.; Kriesel, Jason M.

2015-02-08

We describe a prototype trace gas sensor designed for real-time detection of multiple chemicals. The sensor uses an external cavity quantum cascade laser (ECQCL) swept over its tuning range of 940-1075 cm-1 (9.30-10.7 µm) at a 10 Hz repetition rate.

Improved Multiple-Species Cyclotron Ion Source

NASA Technical Reports Server (NTRS)

Soli, George A.; Nichols, Donald K.

1990-01-01

Use of pure isotope 86Kr instead of natural krypton in multiple-species ion source enables source to produce krypton ions separated from argon ions by tuning cylcotron with which source used. Addition of capability to produce and separate krypton ions at kinetic energies of 150 to 400 MeV necessary for simulation of worst-case ions occurring in outer space.

Balance of dark and luminous mass in rotating galaxies.

PubMed

McGaugh, Stacy S

2005-10-21

A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a fine-tuning problem for galaxy formation models, and may point to new physics for dark matter particles or even a modification of gravity.

Natural SUSY and the Higgs boson

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Peisi

2014-01-01

Supersymmetry (SUSY) solves the hierarchy problem by introducing a super partner to each Standard Model(SM) particle. SUSY must be broken in nature, which means the fine-tuning is reintroduced to some level. Natural SUSY models enjoy low fine-tuning by featuring a small super potential parameter μ ~ 125 GeV, while the third generation squarks have mass less than 1.5 TeV. First and second generation sfermions can be at the multi-TeV level which yields a decoupling solution to the SUSY flavor and CP problem. However, models of Natural SUSY have difficulties in predicting a m{sub h} at 125 GeV, because the thirdmore » generation is too light to give large radiative correction to the Higgs mass. The models of Radiative Natural SUSY (RNS) address this problem by allowing for high scale soft SUSY breaking Higgs mass m{sub Hu} > m{sub 0}, which leads to automatic cancellation by the Renormalization Group (RG) running effect. Coupled with the large mixing in the stop sector, RNS allows low fine-tuning at 3-10 % level and a 125 GeV SM-like Higgs. RNS can be reached at the LHC, and a linear collider. If the strong CP problem is solved by the Peccei-Quinn mechanism, then RNS accommodates mixed axion-Higgsino cold dark matter, where the Higgsino-like WIMPs, which in this case make up only a fraction of the relic abundance, can be detectable at future WIMP detectors.« less

Simplest little Higgs model revisited: Hidden mass relation, unitarity, and naturalness

NASA Astrophysics Data System (ADS)

Cheung, Kingman; He, Shi-Ping; Mao, Ying-nan; Zhang, Chen; Zhou, Yang

2018-06-01

We analyze the scalar potential of the simplest little Higgs (SLH) model in an approach consistent with the spirit of continuum effective field theory (CEFT). By requiring correct electroweak symmetry breaking (EWSB) with the 125 GeV Higgs boson, we are able to derive a relation between the pseudoaxion mass mη and the heavy top mass mT, which serves as a crucial test of the SLH mechanism. By requiring mη2>0 an upper bound on mT can be obtained for any fixed SLH global symmetry breaking scale f . We also point out that an absolute upper bound on f can be obtained by imposing partial wave unitarity constraint, which in turn leads to absolute upper bounds of mT≲19 TeV , mη≲1.5 TeV , and mZ'≲48 TeV . We present the allowed region in the three-dimensional parameter space characterized by f ,tβ,mT, taking into account the requirement of valid EWSB and the constraint from perturbative unitarity. We also propose a strategy of analyzing the fine-tuning problem consistent with the spirit of CEFT and apply it to the SLH. We suggest that the scalar potential and fine-tuning analysis strategies adopted here should also be applicable to a wide class of little Higgs and twin Higgs models, which may reveal interesting relations as crucial tests of the related EWSB mechanism and provide a new perspective on assessing their degree of fine-tuning.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verma, Shweta, E-mail: shwetaverma@rrcat.gov.in; Rao, B. T.; Detty, A. P.

We studied localized surface plasmon resonances (LSPR) at different compositions, substrate temperatures, and mass thicknesses of Ag-Au alloy nanoparticle films grown by sequential pulsed laser deposition. The LSPRs were pronounced at all compositions of the films grown at high substrate temperature of about 300 °C as compared to those grown at room temperature. The alloy formation and composition of the films were determined using X-ray photoelectron and energy dispersive spectroscopy. Films' mass thickness and compositional uniformity along the thickness were determined using X-ray reflectometry and secondary ion mass spectroscopy. Atomic force microscopic analysis revealed the formation of densely packed nanoparticles ofmore » increasing size with the number of laser ablation pulses. The LSPR wavelength red shifted with increasing either Au percentage or film mass thickness and corresponding LSPR tuning was obtained in the range of 450 to 690 nm. The alloy dielectric functions obtained from three different models were compared and the optical responses of the nanoparticle films were calculated from modified Yamaguchi effective medium theory. The tuning of LSPR was found to be due to combined effect of change in intrinsic and extrinsic parameters mainly the composition, morphology, particle-particle, and particle-substrate interactions.« less

Superfluidity of 4He in dense aerogel studied using quartz tuning fork

NASA Astrophysics Data System (ADS)

Matsumoto, K.; Okamoto, R.; Nakajima, A.; Abe, S.

2018-03-01

Superfluid 4He in aerogel is of interest because it has a normal component coupling to gel strand due to viscosity and a superfluid component with zero viscosity. Superfluid helium in aerogel has two sound modes, a slow critical mode and a fast one. In this study, quartz tuning fork was used in order to study acoustic properties of liquid 4He in aerogel with 90% porosity. Two pieces of aerogel were glued on both prongs of quartz tuning fork that had a resonance frequency of 33 kHz. The tuning fork was immersed in liquid 4He from 2 to 20 bar. The resonance frequency increased in the superfluid phase due to decrease in loaded mass. Temperature variation of resonance frequency was explained by that of superfluid density. Superfluid transition in aerogel was 2 mK lower than that without gel. Additional dissipation was observed in the temperature range between 1 K and transition temperature.

A novel scaling law relating the geometrical dimensions of a photocathode radio frequency gun to its radio frequency properties

NASA Astrophysics Data System (ADS)

Lal, Shankar; Pant, K. K.; Krishnagopal, S.

2011-12-01

Developing a photocathode RF gun with the desired RF properties of the π-mode, such as field balance (eb) ˜1, resonant frequency fπ = 2856 MHz, and waveguide-to-cavity coupling coefficient βπ ˜1, requires precise tuning of the resonant frequencies of the independent full- and half-cells (ff and fh), and of the waveguide-to-full-cell coupling coefficient (βf). While contemporary electromagnetic codes and precision machining capability have made it possible to design and tune independent cells of a photocathode RF gun for desired RF properties, thereby eliminating the need for tuning, access to such computational resources and quality of machining is not very widespread. Therefore, many such structures require tuning after machining by employing conventional tuning techniques that are iterative in nature. Any procedure that improves understanding of the tuning process and consequently reduces the number of iterations and the associated risks in tuning a photocathode gun would, therefore, be useful. In this paper, we discuss a method devised by us to tune a photocathode RF gun for desired RF properties under operating conditions. We develop and employ a simple scaling law that accounts for inter-dependence between frequency of independent cells and waveguide-to-cavity coupling coefficient, and the effect of brazing clearance for joining of the two cells. The method has been employed to successfully develop multiple 1.6 cell BNL/SLAC/UCLA type S-band photocathode RF guns with the desired RF properties, without the need to tune them by a tiresome cut-and-measure process. Our analysis also provides a physical insight into how the geometrical dimensions affect the RF properties of the photo-cathode RF gun.

The effect of muscle stiffness and damping on simulated impact force peaks during running.

PubMed

Nigg, B M; Liu, W

1999-08-01

It has been frequently reported that vertical impact force peaks during running change only minimally when changing the midsole hardness of running shoes. However, the underlying mechanism for these experimental observations is not well understood. An athlete has various possibilities to influence external and internal forces during ground contact (e.g. landing velocity, geometrical alignment, muscle tuning, etc.). The purpose of this study was to discuss one possible strategy to influence external impact forces acting on the athlete's body during running, the strategy to change muscle activity (muscle tuning). The human body was modeled as a simplified mass-spring-damper system. The model included masses of the upper and the lower bodies with each part of the body represented by a rigid and a non-rigid wobbling mass. The influence of mechanical properties of the human body on the vertical impact force peak was examined by varying the spring constants and damping coefficients of the spring-damper units that connected the various masses. Two types of shoe soles were modeled using a non-linear force deformation model with two sets of parameters based on the force-deformation curves of pendulum impact experiments. The simulated results showed that the regulation of the mechanical coupling of rigid and wobbling masses of the human body had an influence on the magnitude of the vertical impact force, but not on its loading rate. It was possible to produce the same impact force peaks altering specific mechanical properties of the system for a soft and a hard shoe sole. This regulation can be achieved through changes of joint angles, changes in joint angular velocities and/or changes in muscle activation levels in the lower extremity. Therefore, it has been concluded that changes in muscle activity (muscle tuning) can be used as a possible strategy to affect vertical impact force peaks during running.

The dynamics and tuning of orchestral crotales

NASA Astrophysics Data System (ADS)

Deutsch, Bradley M.; Ramirez, Cherie L.; Moore, Thomas R.

2004-10-01

An experimental and theoretical investigation of the acoustic and vibrational properties of orchestral crotales within the range C6 to C8 is reported. Interferograms of the acoustically important modes of vibration are presented and the frequencies are reported. It is shown that the acoustic spectra of crotales are not predicted by assuming that they are either thin circular plates or annular plates clamped at the center, despite the physical resemblance to these objects. Results from finite element analysis are presented that demonstrate how changing the size of the central mass affects the tuning of the instruments, and it is concluded that crotales are not currently designed to ensure optimal tuning. The possibility of using annular plates as crotales is also investigated and the physical parameters for such a set of instruments are presented. .

Cholesterol-Based Grafted Polymer Brushes as Alignment Coating with Temperature-Tuned Anchoring for Nematic Liquid Crystals.

PubMed

Stetsyshyn, Yurij; Raczkowska, Joanna; Budkowski, Andrzej; Awsiuk, Kamil; Kostruba, Andriy; Nastyshyn, Svyatoslav; Harhay, Khrystyna; Lychkovskyy, Edward; Ohar, Halyna; Nastishin, Yuriy

2016-10-11

Novel alignment coating with temperature-tuned anchoring for nematic liquid crystals (NLCs) was successfully fabricated in three step process, involving polymerization of poly(cholesteryl methacrylate) (PChMa) from oligoproxide grafted to the glass surface premodified with 3-aminopropyltriethoxysilane. Molecular composition, thickness, wettability of the PChMa coating and its alignment action for a NLC were examined with time of flight-secondary ion mass spectrometry, ellipsometry, contact angle measurements, polarization optical microscopy and commercially produced PolScope technique allowing for mapping of the optic axis and optical retardance within the microscope field view. We find that the PChMa coating provides a specific monotonous increase (decrease) in the tilt angle of the NLC director with respect to the substrates normal upon heating (cooling) referred to as anchoring tuning.

Understanding Fire Through Improved Technology

NASA Technical Reports Server (NTRS)

2004-01-01

Aztec(TradeMark) is the commercial name for Southwest Sciences laser. The laser has coarse tuning ranges of 10 nanometers (nm) to 30 nm at wavelengths ranging from 630 nm to 2,300 nm, making it the only commercially available external cavity diode laser with wavelengths beyond 1,650 nm. The laser's high-speed tuning in both coarse and fine wavelength regimes allows for increased trace gas detection. With the automated coarse tuning option, the Aztec sweeps through its wavelength range in less than 1 millisecond. While some diode lasers can only detect one type, or species, of a trace gas, the Aztec's broad wavelength tuning provides access to multiple trace gas species. The Aztec has a wide range of applications for both NASA and commercial users, from protecting astronauts in space to improving combustion processes on Earth. It may serve as a new tool for planetary exploration, as it can detect a wide range of multiple gas species in planetary atmospheres. The laser could optically detect gaseous indicators of incipient fires on the International Space Station and Space Shuttle, as well as detect low concentrations of potentially toxic gases in spacecraft crew habitats. The laser could also provide more accurate fire detection in aircraft cargo compartments. Since the Aztec can detect several gases that only evolve during an actual fire, its implementation could reduce the large number of commercial aircraft landings that currently occur due to false alarms. Other applications include environmental and industrial process monitoring.

Autonomous Performance Monitoring System: Monitoring and Self-Tuning (MAST)

NASA Technical Reports Server (NTRS)

Peterson, Chariya; Ziyad, Nigel A.

2000-01-01

Maintaining the long-term performance of software onboard a spacecraft can be a major factor in the cost of operations. In particular, the task of controlling and maintaining a future mission of distributed spacecraft will undoubtedly pose a great challenge, since the complexity of multiple spacecraft flying in formation grows rapidly as the number of spacecraft in the formation increases. Eventually, new approaches will be required in developing viable control systems that can handle the complexity of the data and that are flexible, reliable and efficient. In this paper we propose a methodology that aims to maintain the accuracy of flight software, while reducing the computational complexity of software tuning tasks. The proposed Monitoring and Self-Tuning (MAST) method consists of two parts: a flight software monitoring algorithm and a tuning algorithm. The dependency on the software being monitored is mostly contained in the monitoring process, while the tuning process is a generic algorithm independent of the detailed knowledge on the software. This architecture will enable MAST to be applicable to different onboard software controlling various dynamics of the spacecraft, such as attitude self-calibration, and formation control. An advantage of MAST over conventional techniques such as filter or batch least square is that the tuning algorithm uses machine learning approach to handle uncertainty in the problem domain, resulting in reducing over all computational complexity. The underlying concept of this technique is a reinforcement learning scheme based on cumulative probability generated by the historical performance of the system. The success of MAST will depend heavily on the reinforcement scheme used in the tuning algorithm, which guarantees the tuning solutions exist.

Designing allostery-inspired response in mechanical networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are then able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ~1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individualmore » response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.« less

Designing allostery-inspired response in mechanical networks

DOE PAGES

Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard; ...

2017-02-21

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are then able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ~1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individualmore » response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.« less

Designing allostery-inspired response in mechanical networks

PubMed Central

Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard; Goodrich, Carl P.; Liu, Andrea J.; Nagel, Sidney R.

2017-01-01

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ∼1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individual response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks. PMID:28223534

Designing allostery-inspired response in mechanical networks.

PubMed

Rocks, Jason W; Pashine, Nidhi; Bischofberger, Irmgard; Goodrich, Carl P; Liu, Andrea J; Nagel, Sidney R

2017-03-07

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ∼1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individual response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.

Reducing the spectral index in supernatural inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, C.-M.; Cheung, Kingman; Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701

2009-04-15

Supernatural inflation is an attractive model based on just a flat direction with soft supersymmetry breaking mass terms in the framework of supersymmetry. The beauty of the model is that it needs no fine-tuning. However, the prediction of the spectral index is n{sub s} > or approx. 1, in contrast to experimental data. In this paper, we discuss supernatural inflation with the spectral index reduced to n{sub s}=0.96 without any fine-tuning, considering the general feature that a flat direction is lifted by a nonrenormalizable term with an A-term.

Measurement of the underlying event in jet events from 7 TeV proton–proton collisions with the ATLAS detector

DOE PAGES

Aad, G.; Abajyan, T.; Abbott, B.; ...

2014-08-12

Distributions sensitive to the underlying event in QCD jet events have been measured with the ATLAS detector at the LHC, based on 37 pb -1 of proton–proton collision data collected at a centre-of-mass energy of 7 TeV. Charged-particle mean p T and densities of all-particle E T and charged-particle multiplicity and p T have been measured in regions azimuthally transverse to the hardest jet in each event. These are presented both as one-dimensional distributions and with their mean values as functions of the leading-jet transverse momentum from 20 to 800 GeV. The correlation of charged-particle mean p T with charged-particlemore » multiplicity is also studied, and the E T densities include the forward rapidity region; these features provide extra data constraints for Monte Carlo modelling of colour reconnection and beam-remnant effects respectively. For the first time, underlying event observables have been computed separately for inclusive jet and exclusive dijet event selections, allowing more detailed study of the interplay of multiple partonic scattering and QCD radiation contributions to the underlying event. Comparisons to the predictions of different Monte Carlo models show a need for further model tuning, but the standard approach is found to generally reproduce the features of the underlying event in both types of event selection.« less

Electrochemical tuning of vertically aligned MoS2 nanofilms and its application in improving hydrogen evolution reaction

PubMed Central

Wang, Haotian; Lu, Zhiyi; Xu, Shicheng; Kong, Desheng; Cha, Judy J.; Zheng, Guangyuan; Hsu, Po-Chun; Yan, Kai; Bradshaw, David; Prinz, Fritz B.; Cui, Yi

2013-01-01

The ability to intercalate guest species into the van der Waals gap of 2D layered materials affords the opportunity to engineer the electronic structures for a variety of applications. Here we demonstrate the continuous tuning of layer vertically aligned MoS2 nanofilms through electrochemical intercalation of Li+ ions. By scanning the Li intercalation potential from high to low, we have gained control of multiple important material properties in a continuous manner, including tuning the oxidation state of Mo, the transition of semiconducting 2H to metallic 1T phase, and expanding the van der Waals gap until exfoliation. Using such nanofilms after different degree of Li intercalation, we show the significant improvement of the hydrogen evolution reaction activity. A strong correlation between such tunable material properties and hydrogen evolution reaction activity is established. This work provides an intriguing and effective approach on tuning electronic structures for optimizing the catalytic activity. PMID:24248362

A Small RNA-Catalytic Argonaute Pathway Tunes Germline Transcript Levels to Ensure Embryonic Divisions

PubMed Central

Gerson-Gurwitz, Adina; Wang, Shaohe; Sathe, Shashank; Green, Rebecca; Yeo, Gene W.; Oegema, Karen; Desai, Arshad

2016-01-01

SUMMARY Multiple division cycles without growth are a characteristic feature of early embryogenesis. The female germline loads proteins and RNAs into oocytes to support these divisions, which lack many quality control mechanisms operating in somatic cells undergoing growth. Here we describe a small RNA-Argonaute pathway that ensures early embryonic divisions in C. elegans by employing catalytic slicing activity to broadly tune, instead of silence, germline gene expression. Misregulation of one target, a kinesin-13 microtubule depolymerase, underlies a major phenotype associated with pathway loss. Tuning of target transcript levels is guided by density of homologous small RNAs, whose generation must ultimately be related to target sequence. Thus, the tuning action of a small RNA-catalytic Argonaute pathway generates oocytes capable of supporting embryogenesis. We speculate that the specialized nature of germline chromatin led to emergence of small RNA-catalytic Argonaute pathways in the female germline as a post-transcriptional control layer to optimize oocyte composition. PMID:27020753

Large trilinear At soft supersymmetry breaking coupling from 5D MSSM

NASA Astrophysics Data System (ADS)

Abdalgabar, Ammar; Cornell, A. S.

2015-10-01

The possibility of generating a large trilinear At soft supersymmetry breaking coupling at low energies through renormalisation group evolution in the 5D MSSM is investigated. Using the power law running in five dimensions and a compactification scale in the 10-103 TeV range, we show that gluino mass may drive a large enough At to reproduce the measured Higgs mass and have a light stop superpartner below ∼ 1 TeV, as preferred by the fine tuning argument for the Higgs mass.

Multiple tuning of magnetic biskyrmions using in situ L-TEM in centrosymmetric MnNiGa alloy

NASA Astrophysics Data System (ADS)

Peng, Licong; Zhang, Ying; He, Min; Ding, Bei; Wang, Wenhong; Li, Jianqi; Cai, Jianwang; Wang, Shouguo; Wu, Guangheng; Shen, Baogen

2018-02-01

Magnetic skyrmions are topologically protected spin configurations and have recently received growingly attention in magnetic materials. The existence of biskyrmions within a broad temperature range has been identified in our newly-discovered MnNiGa material, promising for potential application in physics and technological study. Here, the biskyrmion microscopic origination from the spin configuration evolution of stripe ground state is experimentally identified. The biskyrmion manipulations based on the influences of the basic microstructures and external factors such as grain boundary confinement, sample thickness, electric current, magnetic field and temperature have been systematically studied by using real-space Lorentz transmission electron microscopy. These multiple tuning options help to understand the essential properties of MnNiGa and predict a significant step forward for the realization of skyrmion-based spintronic devices.

Multiband Reconfigurable Harmonically Tuned Gallium Nitride (GaN) Solid-State Power Amplifier (SSPA) for Cognitive Radios

NASA Technical Reports Server (NTRS)

Waldstein, Seth W.; Kortright, Barbosa Miguel A.; Simons, Rainee N.

2017-01-01

The paper presents the architecture of a wideband reconfigurable harmonically-tuned Gallium Nitride (GaN) Solid State Power Amplifier (SSPA) for cognitive radios. When interfaced with the physical layer of a cognitive communication system, this amplifier topology offers broadband high efficiency through the use of multiple tuned input/output matching networks. This feature enables the cognitive radio to reconfigure the operating frequency without sacrificing efficiency. This paper additionally presents as a proof-of-concept the design, fabrication, and test results for a GaN inverse Class-F type amplifier operating at X-band (8.4 GHz) that achieves a maximum output power of 5.14-W, Power Added Efficiency (PAE) of 38.6 percent, and Drain Efficiency (DE) of 48.9 percent under continuous wave (CW) operation.

Tuning of multiple luminescence outputs and white-light emission from a single gelator molecule through an ESIPT coupled AIEE process.

PubMed

Maity, Arunava; Ali, Firoj; Agarwalla, Hridesh; Anothumakkool, Bihag; Das, Amitava

2015-02-07

A unique example of an ESIPT coupled AIEE process, associated with a single molecule (1), is utilized for generating multiple luminescent colors (blue-green-white-yellow). The J-aggregated state of 1 forms a luminescent gel in THF and this luminescent property is retained even in the solid state.

Spontaneous otoacoustic emissions, threshold microstructure, and psychophysical tuning over a wide frequency range in humansa

PubMed Central

Baiduc, Rachael R.; Lee, Jungmee; Dhar, Sumitrajit

2014-01-01

Hearing thresholds have been shown to exhibit periodic minima and maxima, a pattern known as threshold microstructure. Microstructure has previously been linked to spontaneous otoacoustic emissions (SOAEs) and normal cochlear function. However, SOAEs at high frequencies (>4 kHz) have been associated with hearing loss or cochlear pathology in some reports. Microstructure would not be expected near these high-frequency SOAEs. Psychophysical tuning curves (PTCs), the expression of frequency selectivity, may also be altered by SOAEs. Prior comparisons of tuning between ears with and without SOAEs demonstrated sharper tuning in ears with emissions. Here, threshold microstructure and PTCs were compared at SOAE frequencies ranging between 1.2 and 13.9 kHz using subjects without SOAEs as controls. Results indicate: (1) Threshold microstructure is observable in the vicinity of SOAEs of all frequencies; (2) PTCs are influenced by SOAEs, resulting in shifted tuning curve tips, multiple tips, or inversion. High frequency SOAEs show a greater effect on PTC morphology. The influence of most SOAEs at high frequencies on threshold microstructure and PTCs is consistent with those at lower frequencies, suggesting that high-frequency SOAEs reflect the same cochlear processes that lead to SOAEs at lower frequencies. PMID:24437770

Technical design and commissioning of the KATRIN large-volume air coil system

NASA Astrophysics Data System (ADS)

Erhard, M.; Behrens, J.; Bauer, S.; Beglarian, A.; Berendes, R.; Drexlin, G.; Glück, F.; Gumbsheimer, R.; Hergenhan, J.; Leiber, B.; Mertens, S.; Osipowicz, A.; Plischke, P.; Reich, J.; Thümmler, T.; Wandkowsky, N.; Weinheimer, C.; Wüstling, S.

2018-02-01

The KATRIN experiment is a next-generation direct neutrino mass experiment with a sensitivity of 0.2 eV (90% C.L.) to the effective mass of the electron neutrino. It measures the tritium β-decay spectrum close to its endpoint with a spectrometer based on the MAC-E filter technique. The β-decay electrons are guided by a magnetic field that operates in the mT range in the central spectrometer volume; it is fine-tuned by a large-volume air coil system surrounding the spectrometer vessel. The purpose of the system is to provide optimal transmission properties for signal electrons and to achieve efficient magnetic shielding against background. In this paper we describe the technical design of the air coil system, including its mechanical and electrical properties. We outline the importance of its versatile operation modes in background investigation and suppression techniques. We compare magnetic field measurements in the inner spectrometer volume during system commissioning with corresponding simulations, which allows to verify the system's functionality in fine-tuning the magnetic field configuration. This is of major importance for a successful neutrino mass measurement at KATRIN.

ION EFFECTS IN THE APS PARTICLE ACCUMULATOR RING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calvey, J.; Harkay, K.; Yao, CY.

2017-06-25

Trapped ions in the APS Particle Accumulator Ring (PAR) lead to a positive coherent tune shift in both planes, which increases along the PAR cycle as more ions accumulate. This effect has been studied using an ion simulation code developed at SLAC. After modifying the code to include a realistic vacuum profile, multiple ionization, and the effect of shaking the beam to measure the tune, the simulation agrees well with our measurements. This code has also been used to evaluate the possibility of ion instabilities at the high bunch charge needed for the APS-Upgrade.

Users manual for program ADMIT: Admittance and pressure transfer function developed for use on a PC computer

NASA Technical Reports Server (NTRS)

Armstrong, Wilbur C.

1992-01-01

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the ADMIT code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, the splitting of a pipe into unequal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines.

Users manual for program SSFREQ intermediate mode stability curves: Developed for use on a PC computer

NASA Technical Reports Server (NTRS)

Armstrong, Wilbur C.

1992-01-01

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the SSFREQ code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, the splitting of a pipe into equal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines.

Dynamic Responses and Vibration Control of the Transmission Tower-Line System: A State-of-the-Art Review

PubMed Central

Chen, Bo; Guo, Wei-hua; Li, Peng-yun; Xie, Wen-ping

2014-01-01

This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers. PMID:25105161

Floating Offshore WTG Integrated Load Analysis & Optimization Employing a Tuned Mass Damper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez Tsouroukdissian, Arturo; Lackner, Matt; Cross-Whiter, John

2015-09-25

Floating offshore wind turbines (FOWTs) present complex design challenges due to the coupled dynamics of the platform motion, mooring system, and turbine control systems, in response to wind and wave loading. This can lead to higher extreme and fatigue loads than a comparable fixed bottom or onshore system. Previous research[1] has shown the potential to reduced extreme and fatigue loads on FOWT using tuned mass dampers (TMD) for structural control. This project aims to reduce maximum loads using passive TMDs located at the tower top during extreme storm events, when grid supplied power for other controls systems may not bemore » available. The Alstom Haliade 6MW wind turbine is modelled on the Glosten Pelastar tension-leg platform (TLP). The primary objectives of this project are to provide a preliminary assessment of the load reduction potential of passive TMDs on real wind turbine and TLP designs.« less

Radiative corrections in the (varying power)-law modified gravity

NASA Astrophysics Data System (ADS)

Hammad, Fayçal

2015-06-01

Although the (varying power)-law modified gravity toy model has the attractive feature of unifying the early- and late-time expansions of the Universe, thanks to the peculiar dependence of the scalar field's potential on the scalar curvature, the model still suffers from the fine-tuning problem when used to explain the actually observed Hubble parameter. Indeed, a more correct estimate of the mass of the scalar field needed to comply with actual observations gives an unnaturally small value. On the other hand, for a massless scalar field the potential would have no minimum and hence the field would always remain massless. What solves these issues are the radiative corrections that modify the field's effective potential. These corrections raise the field's effective mass, rendering the model free from fine-tuning, immune against positive fifth-force tests, and better suited to tackle the dark matter sector.

Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

NASA Technical Reports Server (NTRS)

Shirley, John A.; Winter, Michael

1993-01-01

An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

Distributed and Dynamic Neural Encoding of Multiple Motion Directions of Transparently Moving Stimuli in Cortical Area MT

PubMed Central

Xiao, Jianbo

2015-01-01

Segmenting visual scenes into distinct objects and surfaces is a fundamental visual function. To better understand the underlying neural mechanism, we investigated how neurons in the middle temporal cortex (MT) of macaque monkeys represent overlapping random-dot stimuli moving transparently in slightly different directions. It has been shown that the neuronal response elicited by two stimuli approximately follows the average of the responses elicited by the constituent stimulus components presented alone. In this scheme of response pooling, the ability to segment two simultaneously presented motion directions is limited by the width of the tuning curve to motion in a single direction. We found that, although the population-averaged neuronal tuning showed response averaging, subgroups of neurons showed distinct patterns of response tuning and were capable of representing component directions that were separated by a small angle—less than the tuning width to unidirectional stimuli. One group of neurons preferentially represented the component direction at a specific side of the bidirectional stimuli, weighting one stimulus component more strongly than the other. Another group of neurons pooled the component responses nonlinearly and showed two separate peaks in their tuning curves even when the average of the component responses was unimodal. We also show for the first time that the direction tuning of MT neurons evolved from initially representing the vector-averaged direction of slightly different stimuli to gradually representing the component directions. Our results reveal important neural processes underlying image segmentation and suggest that information about slightly different stimulus components is computed dynamically and distributed across neurons. SIGNIFICANCE STATEMENT Natural scenes often contain multiple entities. The ability to segment visual scenes into distinct objects and surfaces is fundamental to sensory processing and is crucial for generating the perception of our environment. Because cortical neurons are broadly tuned to a given visual feature, segmenting two stimuli that differ only slightly is a challenge for the visual system. In this study, we discovered that many neurons in the visual cortex are capable of representing individual components of slightly different stimuli by selectively and nonlinearly pooling the responses elicited by the stimulus components. We also show for the first time that the neural representation of individual stimulus components developed over a period of ∼70–100 ms, revealing a dynamic process of image segmentation. PMID:26658869

Electron Raman scattering in a double quantum well tuned by an external nonresonant intense laser field

NASA Astrophysics Data System (ADS)

Tiutiunnyk, A.; Mora-Ramos, M. E.; Morales, A. L.; Duque, C. M.; Restrepo, R. L.; Ungan, F.; Martínez-Orozco, J. C.; Kasapoglu, E.; Duque, C. A.

2017-02-01

In this work we shall present a study of inelastic light scattering involving inter-subband electron transitions in coupled GaAs-(Ga,Al)As quantum wells. Calculations include the electron related Raman differential cross section and Raman gain. The effects of an external nonresonant intense laser field are used in order to tune these output properties. The confined electron states will be described by means of a diagonalization procedure within the effective mass and parabolic band approximations. It is shown that the application of the intense laser field can produce values of the intersubband electron Raman gain above 400 cm-1. The system proposed here is an alternative choice for the development of AlxGa1-xAs semiconductor laser diodes that can be tuned via an external nonresonant intense laser field.

Experiments on nonlinear acoustic landmine detection: Tuning curve studies of soil-mine and soil-mass oscillators

NASA Astrophysics Data System (ADS)

Korman, Murray S.; Witten, Thomas R.; Fenneman, Douglas J.

2004-10-01

Donskoy [SPIE Proc. 3392, 211-217 (1998); 3710, 239-246 (1999)] has suggested a nonlinear technique that is insensitive to relatively noncompliant targets that can detect an acoustically compliant buried mine. Airborne sound at two primary frequencies eventually causes interactions with the soil and mine generating combination frequencies that can affect the vibration velocity at the surface. In current experiments, f1 and f2 are closely spaced near a mine resonance and a laser Doppler vibrometer profiles the surface. In profiling, certain combination frequencies have a much greater contrast ratio than the linear profiles at f1 and f2-but off the mine some nonlinearity exists. Near resonance, the bending (a softening) of a family of tuning curves (over the mine) exhibits a linear relationship between peak velocity and corresponding frequency, which is characteristic of nonlinear mesoscopic elasticity effects that are observed in geomaterials like rocks or granular media. Results are presented for inert plastic VS 1.6, VS 2.2 and M14 mines buried 3.6 cm in loose soil. Tuning curves for a rigid mass plate resting on a soil layer exhibit similar results, suggesting that nonresonant conditions off the mine are desirable. [Work supported by U.S. Army RDECOM, CERDEC, NVESD, Fort Belvoir, VA.

Smart Phase Tuning in Microwave Photonic Integrated Circuits Toward Automated Frequency Multiplication by Design

NASA Astrophysics Data System (ADS)

Nabavi, N.

2018-07-01

The author investigates the monitoring methods for fine adjustment of the previously proposed on-chip architecture for frequency multiplication and translation of harmonics by design. Digital signal processing (DSP) algorithms are utilized to create an optimized microwave photonic integrated circuit functionality toward automated frequency multiplication. The implemented DSP algorithms are formed on discrete Fourier transform and optimization-based algorithms (Greedy and gradient-based algorithms), which are analytically derived and numerically compared based on the accuracy and speed of convergence criteria.

Compound-Specific Chlorine Isotope Analysis of Tetrachloromethane and Trichloromethane by Gas Chromatography-Isotope Ratio Mass Spectrometry vs Gas Chromatography-Quadrupole Mass Spectrometry: Method Development and Evaluation of Precision and Trueness.

PubMed

Heckel, Benjamin; Rodríguez-Fernández, Diana; Torrentó, Clara; Meyer, Armin; Palau, Jordi; Domènech, Cristina; Rosell, Mònica; Soler, Albert; Hunkeler, Daniel; Elsner, Martin

2017-03-21

Compound-specific chlorine isotope analysis of tetrachloromethane (CCl 4 ) and trichloromethane (CHCl 3 ) was explored by both, gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and GC-quadrupole MS (GC-qMS), where GC-qMS was validated in an interlaboratory comparison between Munich and Neuchâtel with the same type of commercial GC-qMS instrument. GC-IRMS measurements analyzed CCl isotopologue ions, whereas GC-qMS analyzed the isotopologue ions CCl 3 , CCl 2 , CCl (of CCl 4 ) and CHCl 3 , CHCl 2 , CHCl (of CHCl 3 ), respectively. Lowest amount dependence (good linearity) was obtained (i) in H-containing fragment ions where interference of 35 Cl- to 37 Cl-containing ions was avoided; (ii) with tuning parameters favoring one predominant rather than multiple fragment ions in the mass spectra. Optimized GC-qMS parameters (dwell time 70 ms, 2 most abundant ions) resulted in standard deviations of 0.2‰ (CHCl 3 ) and 0.4‰ (CCl 4 ), which are only about twice as large as 0.1‰ and 0.2‰ for GC-IRMS. To compare also the trueness of both methods and laboratories, samples from CCl 4 and CHCl 3 degradation experiments were analyzed and calibrated against isotopically different reference standards for both CCl 4 and CHCl 3 (two of each). Excellent agreement confirms that true results can be obtained by both methods provided that a consistent set of isotopically characterized reference materials is used.

Astronomical timescale calibration for the Permian-Triassic boundary transition interval from global correlation of cyclic marine sequences

NASA Astrophysics Data System (ADS)

Huang, C.; Hinnov, L. A.; Tong, J.; Chen, Z.

2011-12-01

The mass extinctions near the Permian-Triassic boundary (PTB) resulted in the greatest dying of life on Earth. The cause of this catastrophe remains enigmatic. High-resolution chronology is crucial to understanding the recorded pattern of biotic evolution and possible causes for the extinctions. Magnetic susceptibility (MS) data from Shangsi, South China shows evidence for astronomical forcing through the PTB interval, with strong 405-kyr cycling. This allows development of an astrochronology for the PTB interval based on the 405-kyr orbital eccentricity metronome that has been proposed for the Mesozoic timescale. Radioisotope dating combined with the 405-kyr tuned MS series from Shangsi shows that the 405-kyr-cycle predominates throughout the PTB interval. In the Permian segment, ~100-kyr cyclicity dominates, and the 100-kyr-scale MS maxima correlate with high-amplitude precession-scale MS variations. Minima in the ~1.5-Myr, 405-kyr and ~100-kyr cycles converge at 252.6 Ma, approximately 200 kyr before the onset of the main mass extinction near the PTB. In the Triassic aftermath, the recorded astronomical signal is different, with predominant 405-kyr cycles and loss of 100 kyr cyclicity, and appearance of ~33 kyr (obliquity scale) cyclicity; 100-kyr cyclicity strengthens again 2 Myr later. This pattern indicates a change in the response of the depositional environment (or magnetic susceptibility) to astronomical forcing before and after the mass extinction interval. The astrochronology interpolates the timescale between the radioisotopically determined absolute dates; this facilitates estimation of ages for specific events in the PTB crisis, including magnetic reversals, biozone boundaries, and the mass extinctions. An estimated ~700 kyr duration for the Mass Extinction Interval (MEI) at Shangsi based on the 405-kyr tuning is supported by eccentricity-tuned estimates of three other sections in China (Meishan, Huangzhishan, and Heping), and two Alpine sections (Gartnerkofel, Austria and Bulla, Italy) from the eastern and western margins of the Palaeo-Tethys Ocean during PTB time. This suggests that the PTB mass extinctions were not the result of a single catastrophic event. Siberian trap volcanism was largely synchronous with the MEI and appears to be the most likely cause of the mass extinctions; astronomically paced climate change may also have played a role.

Suppressed supersymmetry breaking terms in the Higgs sector

NASA Astrophysics Data System (ADS)

Terao, Haruhiko; Kobayashi, Tatsuo

2004-07-01

We study the little hierarchy between mass parameters in the Higgs sector and other SUSY breaking masses. This type of spectrum can relieve the fine-tuning problem in the MSSM Higgs sector. Our scenario can be realized by superconformal dynamics. The spectrum in our scenario has significant implications in other phenomenological aspects like the relic abundance of the lightest neutralino and relaxation of the unbounded-from-below constraints.

Stability of excitons in double quantum well: Through electron and holes transmission probabilities

NASA Astrophysics Data System (ADS)

Vignesh, G.; Nithiananthi, P.

2017-05-01

Stability of excitons has been analyzed using the transmission probability of its constituent particles in GaAs/Al0.3Ga0.7As Double Quantum Well (DQW) structure by varying well and barrier layer thickness. The effective mass approximation is used and anisotropy in material properties are also considered to get realistic situations. It is observed that tuning barrier layer avails many resonance peaks for the transmission and tuning well width admits maximum transmission at narrow well widths. Every saddle point of the observed transmission coefficients decides the formation, strength and transportation of excitons in DQW.

Design of vein finder with multi tuning wavelength using RGB LED

NASA Astrophysics Data System (ADS)

Chandra, Franky; Wahyudianto, Aries; Yasin, M.

2017-05-01

Detection of intra vena is very important technique in the medical clinic applications. For intravenous detection, some nurses usually have a mistake which can cause a pain or injured to the patient. When the nurses are headed with this problem, it becomes dangerous for the patient. To solve the problem, in this paper, vein finder with multi-tuning wavelength for intra vena detection is proposed and investigated. Vein finder is tested to various skin colour and body mass. The results show that vein finder was successfully designed with controllable wavelength in the range of 600-696 nm using RGB LED.

Application of a system modification technique to dynamic tuning of a spinning rotor blade

NASA Technical Reports Server (NTRS)

Spain, C. V.

1987-01-01

An important consideration in the development of modern helicopters is the vibratory response of the main rotor blade. One way to minimize vibration levels is to ensure that natural frequencies of the spinning main rotor blade are well removed from integer multiples of the rotor speed. A technique for dynamically tuning a finite-element model of a rotor blade to accomplish that end is demonstrated. A brief overview is given of the general purpose finite element system known as Engineering Analysis Language (EAL) which was used in this work. A description of the EAL System Modification (SM) processor is then given along with an explanation of special algorithms developed to be used in conjunction with SM. Finally, this technique is demonstrated by dynamically tuning a model of an advanced composite rotor blade.

Specialization of the auditory system for the processing of bio-sonar information in the frequency domain: Mustached bats.

PubMed

Suga, Nobuo

2018-04-01

For echolocation, mustached bats emit velocity-sensitive orientation sounds (pulses) containing a constant-frequency component consisting of four harmonics (CF 1-4 ). They show unique behavior called Doppler-shift compensation for Doppler-shifted echoes and hunting behavior for frequency and amplitude modulated echoes from fluttering insects. Their peripheral auditory system is highly specialized for fine frequency analysis of CF 2 (∼61.0 kHz) and detecting echo CF 2 from fluttering insects. In their central auditory system, lateral inhibition occurring at multiple levels sharpens V-shaped frequency-tuning curves at the periphery and creates sharp spindle-shaped tuning curves and amplitude tuning. The large CF 2 -tuned area of the auditory cortex systematically represents the frequency and amplitude of CF 2 in a frequency-versus-amplitude map. "CF/CF" neurons are tuned to a specific combination of pulse CF 1 and Doppler-shifted echo CF 2 or 3 . They are tuned to specific velocities. CF/CF neurons cluster in the CC ("C" stands for CF) and DIF (dorsal intrafossa) areas of the auditory cortex. The CC area has the velocity map for Doppler imaging. The DIF area is particularly for Dopper imaging of other bats approaching in cruising flight. To optimize the processing of behaviorally relevant sounds, cortico-cortical interactions and corticofugal feedback modulate the frequency tuning of cortical and sub-cortical auditory neurons and cochlear hair cells through a neural net consisting of positive feedback associated with lateral inhibition. Copyright © 2018 Elsevier B.V. All rights reserved.

Dynamic analysis of periodic vibration suppressors with multiple secondary oscillators

NASA Astrophysics Data System (ADS)

Ma, Jiangang; Sheng, Meiping; Guo, Zhiwei; Qin, Qi

2018-06-01

A periodic vibration suppressor with multiple secondary oscillators is examined in this paper to reduce the low-frequency vibration. The band-gap properties of infinite periodic structure and vibration transmission properties of finite periodic structure attached with secondary oscillators with arbitrary degree of freedom are thoroughly analyzed by the plane-wave-expansion method. A simply supported plate with a periodic rectangular array of vibration suppressors is considered. The dynamic model of this periodic structure is established and the equation of harmonic vibration response is theoretically derived and numerically examined. Compared with the simply supported plate without attached suppressors, the proposed plate can obtain better vibration control, and the vibration response can be effectively reduced in several frequency bands owing to the multiple band-gap property. By analyzing the modal properties of the periodic vibration suppressors, the relationship between modal frequencies and the parameters of spring stiffness and mass is established. With the numerical results, the design guidance of the locally resonant structure with multiple secondary oscillators is proposed to provide practical guidance for application. Finally, a practical periodic specimen is designed and fabricated, and then an experiment is carried out to validate the effectiveness of periodic suppressors in the reality. The results show that the experimental band gaps have a good coincidence with those in the theoretical model, and the low-frequency vibration of the plate with periodic suppressors can be effectively reduced in the tuned band gaps. Both the theoretical results and experimental results prove that the design method is effective and the structure with periodic suppressors has a promising application in engineering.

Analytical investigation of the dynamics of tethered constellations in Earth orbit, phase 2

NASA Technical Reports Server (NTRS)

Lorenzini, E. C.; Arnold, D. A.; Grossi, M. D.; Gullahorn, G. E.

1986-01-01

The g-tuning maneuvers of a 3-mass, vertical tethered system are considered. In particular, the case of reaching a zero-g acceleration level on board the middle mass from a non-zero initial condition is analyzed. A control law that provides a satisfactory transient response is derived. The constellation dynamics in the case of the middle mass travelling from one tether tip to the other is also investigated. Instabilities that take place at the end of the maneuver are analyzed and accommodated by devising suitable damping algorithms.

Neurons in the inferior colliculus of the rat show stimulus-specific adaptation for frequency, but not for intensity

PubMed Central

Duque, Daniel; Wang, Xin; Nieto-Diego, Javier; Krumbholz, Katrin; Malmierca, Manuel S.

2016-01-01

Electrophysiological and psychophysical responses to a low-intensity probe sound tend to be suppressed by a preceding high-intensity adaptor sound. Nevertheless, rare low-intensity deviant sounds presented among frequent high-intensity standard sounds in an intensity oddball paradigm can elicit an electroencephalographic mismatch negativity (MMN) response. This has been taken to suggest that the MMN is a correlate of true change or “deviance” detection. A key question is where in the ascending auditory pathway true deviance sensitivity first emerges. Here, we addressed this question by measuring low-intensity deviant responses from single units in the inferior colliculus (IC) of anesthetized rats. If the IC exhibits true deviance sensitivity to intensity, IC neurons should show enhanced responses to low-intensity deviant sounds presented among high-intensity standards. Contrary to this prediction, deviant responses were only enhanced when the standards and deviants differed in frequency. The results could be explained with a model assuming that IC neurons integrate over multiple frequency-tuned channels and that adaptation occurs within each channel independently. We used an adaptation paradigm with multiple repeated adaptors to measure the tuning widths of these adaption channels in relation to the neurons’ overall tuning widths. PMID:27066835

Interface circuit for a multiple-beam tuning-fork gyroscope with high quality factors

NASA Astrophysics Data System (ADS)

Wang, Ren

This research work presents the design, theoretical analysis, fabrication, interface electronics, and experimental results of a Silicon-On-Insulator (SOI) based Multiple-Beam Tuning-Fork Gyroscope (MB-TFG). Based on a numerical model of Thermo-Elastic Damping (TED), a Multiple-Beam Tuning-Fork Structure (MB-TFS) is designed with high Quality factors (Qs) in its two operation modes. A comprehensive theoretical analysis of the MB-TFG design is conducted to relate the design parameters to its operation parameters and further performance parameters. In conjunction with a mask that defines the device through trenches to alleviate severe fabrication effect on anchor loss, a simple one-mask fabrication process is employed to implement this MB-TFG design on SOI wafers. The fabricated MB-TFGs are tested with PCB-level interface electronics and a thorough comparison between the experimental results and a theoretical analysis is conducted to verify the MB-TFG design and accurately interpret the measured performance. The highest measured Qs of the fabricated MB-TFGs in vacuum are 255,000 in the drive-mode and 103,000 in the sense-mode, at a frequency of 15.7kHz. Under a frequency difference of 4Hz between the two modes (operation frequency is 16.8kHz) and a drive-mode vibration amplitude of 3.0um, the measured rate sensitivity is 80mVpp/°/s with an equivalent impedance of 6MQ. The calculated overall rate resolution of this device is 0.37/hrhiElz, while the measured Angle Random Walk (ARW) and bias instability are 6.67°/'vhr and 95°/hr, respectively.

Multiple harmonic frequencies resonant cavity design and half-scale prototype measurements for a fast kicker

DOE PAGES

Huang, Yulu; Wang, Haipeng; Wang, Shaoheng; ...

2016-12-09

Quarter wavelength resonator (QWR) based deflecting cavities with the capability of supporting multiple odd-harmonic modes have been developed for an ultrafast periodic kicker system in the proposed Jefferson Lab Electron Ion Collider (JLEIC, formerly MEIC). Previous work on the kicking pulse synthesis and the transverse beam dynamics tracking simulations show that a flat-top kicking pulse can be generated with minimal emittance growth during injection and circulation of the cooling electron bunches. This flat-top kicking pulse can be obtained when a DC component and 10 harmonic modes with appropriate amplitude and phase are combined together. To support 10 such harmonic modes,more » four QWR cavities are used with 5, 3, 1, and 1 modes, respectively. In the multiple-mode cavities, several slightly tapered segments of the inner conductor are introduced to tune the higher order deflecting modes to be harmonic, and stub tuners are used to fine tune each frequency to compensate for potential errors. In this paper, we summarize the electromagnetic design of the five-mode cavity, including the geometry optimization to get high transverse shunt impedance, the frequency tuning and sensitivity analysis, and the single loop coupler design for coupling to all of the harmonic modes. In particular we report on the design and fabrication of a half-scale copper prototype of this proof-of-principle five-odd-mode cavity, as well as the rf bench measurements. Lastly, we demonstrate mode superposition in this cavity experimentally, which illustrates the kicking pulse generation concept.« less

Experimental test of an online ion-optics optimizer

NASA Astrophysics Data System (ADS)

Amthor, A. M.; Schillaci, Z. M.; Morrissey, D. J.; Portillo, M.; Schwarz, S.; Steiner, M.; Sumithrarachchi, Ch.

2018-07-01

A technique has been developed and tested to automatically adjust multiple electrostatic or magnetic multipoles on an ion optical beam line - according to a defined optimization algorithm - until an optimal tune is found. This approach simplifies the process of determining high-performance optical tunes, satisfying a given set of optical properties, for an ion optical system. The optimization approach is based on the particle swarm method and is entirely model independent, thus the success of the optimization does not depend on the accuracy of an extant ion optical model of the system to be optimized. Initial test runs of a first order optimization of a low-energy (<60 keV) all-electrostatic beamline at the NSCL show reliable convergence of nine quadrupole degrees of freedom to well-performing tunes within a reasonable number of trial solutions, roughly 500, with full beam optimization run times of roughly two hours. Improved tunes were found both for quasi-local optimizations and for quasi-global optimizations, indicating a good ability of the optimizer to find a solution with or without a well defined set of initial multipole settings.

PERI - Auto-tuning Memory Intensive Kernels for Multicore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, David H; Williams, Samuel; Datta, Kaushik

2008-06-24

We present an auto-tuning approach to optimize application performance on emerging multicore architectures. The methodology extends the idea of search-based performance optimizations, popular in linear algebra and FFT libraries, to application-specific computational kernels. Our work applies this strategy to Sparse Matrix Vector Multiplication (SpMV), the explicit heat equation PDE on a regular grid (Stencil), and a lattice Boltzmann application (LBMHD). We explore one of the broadest sets of multicore architectures in the HPC literature, including the Intel Xeon Clovertown, AMD Opteron Barcelona, Sun Victoria Falls, and the Sony-Toshiba-IBM (STI) Cell. Rather than hand-tuning each kernel for each system, we developmore » a code generator for each kernel that allows us to identify a highly optimized version for each platform, while amortizing the human programming effort. Results show that our auto-tuned kernel applications often achieve a better than 4X improvement compared with the original code. Additionally, we analyze a Roofline performance model for each platform to reveal hardware bottlenecks and software challenges for future multicore systems and applications.« less

Error-based analysis of optimal tuning functions explains phenomena observed in sensory neurons.

PubMed

Yaeli, Steve; Meir, Ron

2010-01-01

Biological systems display impressive capabilities in effectively responding to environmental signals in real time. There is increasing evidence that organisms may indeed be employing near optimal Bayesian calculations in their decision-making. An intriguing question relates to the properties of optimal encoding methods, namely determining the properties of neural populations in sensory layers that optimize performance, subject to physiological constraints. Within an ecological theory of neural encoding/decoding, we show that optimal Bayesian performance requires neural adaptation which reflects environmental changes. Specifically, we predict that neuronal tuning functions possess an optimal width, which increases with prior uncertainty and environmental noise, and decreases with the decoding time window. Furthermore, even for static stimuli, we demonstrate that dynamic sensory tuning functions, acting at relatively short time scales, lead to improved performance. Interestingly, the narrowing of tuning functions as a function of time was recently observed in several biological systems. Such results set the stage for a functional theory which may explain the high reliability of sensory systems, and the utility of neuronal adaptation occurring at multiple time scales.

Tunable graphene-based mid-infrared plasmonic multispectral and narrow band-stop filter

NASA Astrophysics Data System (ADS)

Wang, Xianjun; Meng, Hongyun; Liu, Shuai; Deng, Shuying; Jiao, Tao; Wei, Zhongchao; Wang, Faqiang; Tan, Chunhua; Huang, Xuguang

2018-04-01

In this paper, we numerically investigate the band-stop properties of single- or few-layers doped graphene ribbon arrays operating in the mid-infrared region by finite-difference time-domain method (FDTD). A perfect band-stop filter with extinction ratio (ER) ∼17 dB, 3 dB bandwidth ∼200 nm and the resonance notch located at 6.64 μm can be achieved. And desired working regions can be obtained by tuning the Fermi level (E f ) of the graphene ribbons and the geometrical parameters of the structure. Besides, by tuning the Fermi level of odd or even graphene ribbons with terminal gate voltage, we can achieve a dual-circuit switch with four states combinations of on-to-off. Furthermore, the multiple filter notches can be achieved by stacking few-layers structure, and the filter dips can be dynamically tuned to achieve the tunability and selective characteristics by tuning the Fermi-level of the graphene ribbons in the system. We believe that our proposal has the potential applications in selective filters and active plasmonic switching in the mid-infrared region.

Attention selectively modifies the representation of individual faces in the human brain

PubMed Central

Gratton, Caterina; Sreenivasan, Kartik K.; Silver, Michael A.; D’Esposito, Mark

2013-01-01

Attention modifies neural tuning for low-level features, but it is unclear how attention influences tuning for complex stimuli. We investigated this question in humans using fMRI and face stimuli. Participants were shown six faces (F1-F6) along a morph continuum, and selectivity was quantified by constructing tuning curves for individual voxels. Face-selective voxels exhibited greater responses to their preferred face than to non-preferred faces, particularly in posterior face areas. Anterior face areas instead displayed tuning for face categories: voxels in these areas preferred either the first (F1-F3) or second (F4-F6) half of the morph continuum. Next, we examined the effects of attention on voxel tuning by having subjects direct attention to one of the superimposed images of F1 and F6. We found that attention selectively enhanced responses in voxels preferring the attended face. Taken together, our results demonstrate that single voxels carry information about individual faces and that the nature of this information varies across cortical face areas. Additionally, we found that attention selectively enhances these representations. Our findings suggest that attention may act via a unitary principle of selective enhancement of responses to both simple and complex stimuli across multiple stages of the visual hierarchy. PMID:23595755

SUSY: Quo Vadis?

NASA Astrophysics Data System (ADS)

Ross, G. G.

2014-05-01

Given that there is currently no direct evidence for supersymmetric particles at the LHC it is timely to re-evaluate the need for low scale supersymmetry and to ask whether it is likely to be discoverable by the LHC running at its full energy. We review the status of simple SUSY extensions of the Standard Model in the light of the Higgs discovery and the non-observation of evidence for SUSY at the LHC. The need for large radiative corrections to drive the Higgs mass up to 126 GeV and for the coloured SUSY states to be heavy to explain their non-observation introduces a little hierarchy problem and we discuss how to quantify the associated fine tuning. The requirement of low fine tuning requires non-minimal SUSY extensions and we discuss the nature and phenomenology of models which still have perfectly acceptable low fine tuning. A brief discussion of SUSY flavour-changing and CP-violation problems and their resolution is presented.

New approach to flavor symmetry and an extended naturalness principle

NASA Astrophysics Data System (ADS)

Barr, S. M.

2010-09-01

A class of nonsupersymmetric extensions of the standard model is proposed in which there is a multiplicity of light scalar doublets in a multiplet of a nonabelian family group with the standard model Higgs doublet. Anthropic tuning makes the latter light, and consequently the other scalar doublets remain light because of the family symmetry. The family symmetry greatly constrains the pattern of flavor-changing neutral-current interactions (FCNC) and p decay operators coming from scalar-exchange. Such models show that useful constraints on model-building can come from an extended naturalness principle when the electroweak scale is anthropically tuned.

Model for the computation of self-motion in biological systems

NASA Technical Reports Server (NTRS)

Perrone, John A.

1992-01-01

A technique is presented by which direction- and speed-tuned cells, such as those commonly found in the middle temporal region of the primate brain, can be utilized to analyze the patterns of retinal image motion that are generated during observer movement through the environment. The developed model determines heading by finding the peak response in a population of detectors or neurons each tuned to a particular heading direction. It is suggested that a complex interaction of multiple cell networks is required for the solution of the self-motion problem in the primate brain.

Properties of jets measured from tracks in proton-proton collisions at center-of-mass energy s = 7 TeV with the ATLAS detector

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2011-09-20

Jets are identified and their properties studied in center-of-mass energy √s = 7 TeV proton-proton collisions at the Large Hadron Collider using charged particles measured by the ATLAS inner detector. Events are selected using a minimum bias trigger, allowing jets at very low transverse momentum to be observed and their characteristics in the transition to high-momentum fully perturbative jets to be studied. Jets are reconstructed using the anti-k t algorithm applied to charged particles with two radius parameter choices, 0.4 and 0.6. An inclusive charged jet transverse momentum cross section measurement from 4 GeV to 100 GeV is shown formore » four ranges in rapidity extending to 1.9 and corrected to charged particle-level truth jets. The transverse momenta and longitudinal momentum fractions of charged particles within jets are measured, along with the charged particle multiplicity and the particle density as a function of radial distance from the jet axis. Comparison of the data with the theoretical models implemented in existing tunings of Monte Carlo event generators indicates reasonable overall agreement between data and Monte Carlo. In conclusion, these comparisons are sensitive to Monte Carlo parton showering, hadronization, and soft physics models.« less

Relating structure and composition with accessibility of a single catalyst particle using correlative 3-dimensional micro-spectroscopy

DOE PAGES

Liu, Yijin; Meirer, Florian; Krest, Courtney M.; ...

2016-08-30

To understand how hierarchically structured functional materials operate, analytical tools are needed that can reveal small structural and chemical details in large sample volumes. Often, a single method alone is not sufficient to get a complete picture of processes happening at multiple length scales. Here we present a correlative approach combining three-dimensional X-ray imaging techniques at different length scales for the analysis of metal poisoning of an individual catalyst particle. The correlative nature of the data allowed establishing a macro-pore network model that interprets metal accumulations as a resistance to mass transport and can, by tuning the effect of metalmore » deposition, simulate the response of the network to a virtual ageing of the catalyst particle. In conclusion, the developed approach is generally applicable and provides an unprecedented view on dynamic changes in a material’s pore space, which is an essential factor in the rational design of functional porous materials.« less

Measurement of underlying event characteristics using charged particles in pp collisions at s=900GeV and 7 TeV with the ATLAS detector

NASA Astrophysics Data System (ADS)

Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Ackers, M.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahmed, H.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Aleppo, M.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, J.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Antunovic, B.; Anulli, F.; Aoun, S.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Argyropoulos, T.; Arik, E.; Arik, M.; Armbruster, A. J.; Arms, K. E.; Armstrong, S. R.; Arnaez, O.; Arnault, C.; Artamonov, A.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, D.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H. S.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Belhorma, B.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, G.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biscarat, C.; Bischof, R.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Boaretto, C.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocci, A.; Bock, R.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boonekamp, M.; Boorman, G.; Booth, C. N.; Booth, P.; Booth, J. R. 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W.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schweiger, D.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W. G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Seliverstov, D. M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M. E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shank, J. T.; Shao, Q. T.; Shapiro, M.; Shatalov, P. B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M. J.; Short, D.; Shupe, M. A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siegert, F.; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S. B.; Simak, V.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N. B.; Sipica, V.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinnari, L. A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T. J.; Sloper, J.; Smakhtin, V.; Smirnov, S. Yu.; Smirnova, L. N.; Smirnova, O.; Smith, B. C.; Smith, D.; Smith, K. M.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snow, S. W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C. A.; Solar, M.; Solc, J.; Soldevila, U.; Solfaroli Camillocci, E.; Solodkov, A. A.; Solovyanov, O. V.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spanò, F.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R. D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Stefanidis, E.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G. A.; Stockmanns, T.; Stockton, M. C.; Stodulski, M.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A. R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Strong, J. A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Stupak, J.; Sturm, P.; Soh, D. A.; Su, D.; Subramania, S.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M. R.; Suzuki, Y.; Sviridov, Yu. M.; Swedish, S.; Sykora, I.; Sykora, T.; Szeless, B.; Sánchez, J.; Ta, D.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M. C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tannoury, N.; Tappern, G. P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F. E.; Taylor, G.; Taylor, G. N.; Taylor, W.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Tennenbaum-Katan, Y. D.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R. J.; Tevlin, C. M.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J. P.; Thompson, E. N.; Thompson, P. D.; Thompson, P. D.; Thompson, A. S.; Thomson, E.; Thomson, M.; Thun, R. P.; Tic, T.; Tikhomirov, V. O.; Tikhonov, Y. A.; Timmermans, C. J. W. P.; Tipton, P.; Tique Aires Viegas, F. J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokár, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomoto, M.; Tompkins, L.; Toms, K.; Tonazzo, A.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N. D.; Torchiani, I.; Torrence, E.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Traynor, D.; Trefzger, T.; Treis, J.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Trinh, T. N.; Tripiana, M. F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiakiris, M.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsung, J.-W.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tuggle, J. M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Typaldos, D.; Tyrvainen, H.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D. G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urquijo, P.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; van der Graaf, H.; van der Kraaij, E.; van der Poel, E.; van der Ster, D.; van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E. W.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vassilakopoulos, V. I.; Vazeille, F.; Vegni, G.; Veillet, J. J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Ventura, S.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vertogardov, L.; Vetterli, M. C.; Vichou, I.; Vickey, T.; Viehhauser, G. H. A.; Viel, S.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinek, E.; Vinogradov, V. B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A. P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T. T.; Vossebeld, J. H.; Vovenko, A. S.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Wahrmund, S.; Wakabayashi, J.; Walbersloh, J.; Walch, S.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, J.; Wang, J. C.; Wang, S. M.; Warburton, A.; Ward, C. P.; Warsinsky, M.; Wastie, R.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, A. T.; Waugh, B. M.; Weber, J.; Weber, M.; Weber, M. S.; Weber, P.; Weidberg, A. R.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P. S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Wessels, M.; Whalen, K.; Wheeler-Ellis, S. J.; Whitaker, S. P.; White, A.; White, M. J.; Whitehead, S. R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L. A. M.; Wildauer, A.; Wildt, M. A.; Wilhelm, I.; Wilkens, H. G.; Will, J. Z.; Williams, E.; Williams, H. H.; Willis, W.; Willocq, S.; Wilson, J. A.; Wilson, M. G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wolter, M. W.; Wolters, H.; Wooden, G.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wraight, K.; Wright, C.; Wrona, B.; Wu, S. L.; Wu, X.; Wulf, E.; Wunstorf, R.; Wynne, B. M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, S.; Yang, U. K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, W.-M.; Yao, Y.; Yasu, Y.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.; Yu, D.; Yu, J.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaets, V. G.; Zaidan, R.; Zaitsev, A. M.; Zajacova, Z.; Zalite, Yo. K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zdrazil, M.; Zeitnitz, C.; Zeller, M.; Zema, P. F.; Zemla, A.; Zendler, C.; Zenin, A. V.; Zenin, O.; Ženiš, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi Della Porta, G.; Zhan, Z.; Zhang, H.; Zhang, J.; Zhang, X.; Zhang, Z.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C. G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zieminska, D.; Zilka, B.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Živković, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; Zur Nedden, M.; Zutshi, V.; Zwalinski, L.

2011-06-01

Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV. The “underlying event” is defined as those aspects of a hadronic interaction attributed not to the hard scattering process, but rather to the accompanying interactions of the rest of the proton. Three regions are defined in azimuthal angle with respect to the highest transverse momentum charged particle in the event, such that the region transverse to the dominant momentum-flow is most sensitive to the underlying event. In each of these regions, distributions of the charged particle multiplicity, transverse momentum density, and average pT are measured. The data show generally higher underlying event activity than that predicted by Monte Carlo models tuned to pre-LHC data.

Analytical investigation of the dynamics of tethered constellations in Earth orbit, phase 2

NASA Technical Reports Server (NTRS)

Lorenzini, E.; Arnold, D. A.; Grossi, M. D.; Gullahorn, G. E.

1986-01-01

The development of a two dimensional analytical model that describes the dynamics of an n-mass vertical tethered system is reported. Two different approaches are described: in the first one the control quantities are the independent variables while in the second one the Cartesian coordinates of each mass expressed in the orbiting reference frame are the independent variables. The latter model was used in the 3-mass version to simulate the dynamics of the tethered system in applications involving the displacement of the middle mass along the tether. In particular, issues related to reproducing predetermined acceleration profiles and g-tuning are reported.

Dynamic transfer applied to secondary ion imaging over large scanned fields with the nanoSIMS 50 at high mass resolution

NASA Astrophysics Data System (ADS)

Slodzian, Georges; Wu, Ting-Di; Duprat, Jean; Engrand, Cécile; Guerquin-Kern, Jean-Luc

2017-12-01

Dynamic transfer is an adaptive optical approach used for coupling a scanning ion probe with the mass spectrometer designed for analyzing sputtered ions emanating from the probe impact. Its tuning is of crucial importance for getting uniform signal collection over large scanning fields and therefore scanning images free of vignetting in a context of high mass resolution. Revisiting the optical design of the NanoSIMS 50 instrument, where the same set of lenses focuses the primary ion probe on the sample and collects secondary ions from the sample, led us to develop novel experimental procedures to achieve dynamic transfer tuning and overcome instrumental imperfections. It is the case for scanning distortion that may be induced by the octopole used for correcting probe astigmatism and may cause irreducible vignetting on scanning images. We show that it is possible to develop complete tuning procedures by compromising temporarily on the sharpness of the probe focus. Most importantly, we show that, in a context of high mass resolution, the transfer does not significantly disturb isotopic ratios over large scanned fields provided external coils are properly adjusted to compensate ambient magnetic fields. Deepening the procedures led us to demonstrate that the scanning center of the probe may not coincide with the imaging center of COOL, Coaxial Objective Lenses forming the probe and extracting secondary ions. We have checked that bringing those two centers into coincidence resulted in a better image quality over large fields. In the present work, we show how to handle the secondary beam in order to position it before it enters the spectrometer. That capability is essential for optimizing transmission at high mass resolution by aligning the secondary beam axis on a given entrance axis of the spectrometer. These results led us to propose several instrumental improvements including the crucial interest of an additional octopole upstream in the primary ion probe column to prevent scanning distortion when performing astigmatism correction and the possibility of offsetting primary beam deviating plates to bring scanning and imaging centers in coincidence.

Post-LHC7 fine-tuning in the minimal supergravity/CMSSM model with a 125 GeV Higgs boson

NASA Astrophysics Data System (ADS)

Baer, Howard; Barger, Vernon; Huang, Peisi; Mickelson, Dan; Mustafayev, Azar; Tata, Xerxes

2013-02-01

The recent discovery of a 125 GeV Higgs-like resonance at LHC, coupled with the lack of evidence for weak scale supersymmetry (SUSY), has severely constrained SUSY models such as minimal supergravity (mSUGRA)/CMSSM. As LHC probes deeper into SUSY model parameter space, the little hierarchy problem—how to reconcile the Z and Higgs boson mass scale with the scale of SUSY breaking—will become increasingly exacerbated unless a sparticle signal is found. We evaluate two different measures of fine-tuning in the mSUGRA/CMSSM model. The more stringent of these, ΔHS, includes effects that arise from the high-scale origin of the mSUGRA parameters while the second measure, ΔEW, is determined only by weak scale parameters: hence, it is universal to any model with the same particle spectrum and couplings. Our results incorporate the latest constraints from LHC7 sparticle searches, LHCb limits from Bs→μ+μ- and also require a light Higgs scalar with mh˜123-127GeV. We present fine-tuning contours in the m0 vs m1/2 plane for several sets of A0 and tan⁡β values. We also present results for ΔHS and ΔEW from a scan over the entire viable model parameter space. We find a ΔHS≳103, or at best 0.1%, fine-tuning. For the less stringent electroweak fine-tuning, we find ΔEW≳102, or at best 1%, fine-tuning. Two benchmark points are presented that have the lowest values of ΔHS and ΔEW. Our results provide a quantitative measure for ascertaining whether or not the remaining mSUGRA/CMSSM model parameter space is excessively fine-tuned and so could provide impetus for considering alternative SUSY models.

Blue straggler formation at core collapse

NASA Astrophysics Data System (ADS)

Banerjee, Sambaran

Among the most striking feature of blue straggler stars (BSS) in globular clusters is the presence of multiple sequences of BSSs in the colour-magnitude diagrams (CMDs) of several globular clusters. It is often envisaged that such a multiple BSS sequence would arise due a recent core collapse of the host cluster, triggering a number of stellar collisions and binary mass transfers simultaneously over a brief episode of time. Here we examine this scenario using direct N-body computations of moderately-massive star clusters (of order 104 {M⊙). As a preliminary attempt, these models are initiated with ≈8-10 Gyr old stellar population and King profiles of high concentrations, being ``tuned'' to undergo core collapse quickly. BSSs are indeed found to form in a ``burst'' at the onset of the core collapse and several of such BS-bursts occur during the post-core-collapse phase. In those models that include a few percent primordial binaries, both collisional and binary BSSs form after the onset of the (near) core-collapse. However, there is as such no clear discrimination between the two types of BSSs in the corresponding computed CMDs. We note that this may be due to the less number of BSSs formed in these less massive models than that in actual globular clusters.

Updating the Finite Element Model of the Aerostructures Test Wing Using Ground Vibration Test Data

NASA Technical Reports Server (NTRS)

Lung, Shun-Fat; Pak, Chan-Gi

2009-01-01

Improved and/or accelerated decision making is a crucial step during flutter certification processes. Unfortunately, most finite element structural dynamics models have uncertainties associated with model validity. Tuning the finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. The model tuning process requires not only satisfactory correlations between analytical and experimental results, but also the retention of the mass and stiffness properties of the structures. Minimizing the difference between analytical and experimental results is a type of optimization problem. By utilizing the multidisciplinary design, analysis, and optimization (MDAO) tool in order to optimize the objective function and constraints; the mass properties, the natural frequencies, and the mode shapes can be matched to the target data to retain the mass matrix orthogonality. This approach has been applied to minimize the model uncertainties for the structural dynamics model of the aerostructures test wing (ATW), which was designed and tested at the National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California). This study has shown that natural frequencies and corresponding mode shapes from the updated finite element model have excellent agreement with corresponding measured data.

Updating the Finite Element Model of the Aerostructures Test Wing using Ground Vibration Test Data

NASA Technical Reports Server (NTRS)

Lung, Shun-fat; Pak, Chan-gi

2009-01-01

Improved and/or accelerated decision making is a crucial step during flutter certification processes. Unfortunately, most finite element structural dynamics models have uncertainties associated with model validity. Tuning the finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. The model tuning process requires not only satisfactory correlations between analytical and experimental results, but also the retention of the mass and stiffness properties of the structures. Minimizing the difference between analytical and experimental results is a type of optimization problem. By utilizing the multidisciplinary design, analysis, and optimization (MDAO) tool in order to optimize the objective function and constraints; the mass properties, the natural frequencies, and the mode shapes can be matched to the target data to retain the mass matrix orthogonality. This approach has been applied to minimize the model uncertainties for the structural dynamics model of the Aerostructures Test Wing (ATW), which was designed and tested at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center (DFRC) (Edwards, California). This study has shown that natural frequencies and corresponding mode shapes from the updated finite element model have excellent agreement with corresponding measured data.

Quantitative Comparison of Tandem Mass Spectra Obtained on Various Instruments

NASA Astrophysics Data System (ADS)

Bazsó, Fanni Laura; Ozohanics, Oliver; Schlosser, Gitta; Ludányi, Krisztina; Vékey, Károly; Drahos, László

2016-08-01

The similarity between two tandem mass spectra, which were measured on different instruments, was compared quantitatively using the similarity index (SI), defined as the dot product of the square root of peak intensities in the respective spectra. This function was found to be useful for comparing energy-dependent tandem mass spectra obtained on various instruments. Spectral comparisons show the similarity index in a 2D "heat map", indicating which collision energy combinations result in similar spectra, and how good this agreement is. The results and methodology can be used in the pharma industry to design experiments and equipment well suited for good reproducibility. We suggest that to get good long-term reproducibility, it is best to adjust the collision energy to yield a spectrum very similar to a reference spectrum. It is likely to yield better results than using the same tuning file, which, for example, does not take into account that contamination of the ion source due to extended use may influence instrument tuning. The methodology may be used to characterize energy dependence on various instrument types, to optimize instrumentation, and to study the influence or correlation between various experimental parameters.

Constructing an Efficient Self-Tuning Aircraft Engine Model for Control and Health Management Applications

NASA Technical Reports Server (NTRS)

Armstrong, Jeffrey B.; Simon, Donald L.

2012-01-01

Self-tuning aircraft engine models can be applied for control and health management applications. The self-tuning feature of these models minimizes the mismatch between any given engine and the underlying engineering model describing an engine family. This paper provides details of the construction of a self-tuning engine model centered on a piecewise linear Kalman filter design. Starting from a nonlinear transient aerothermal model, a piecewise linear representation is first extracted. The linearization procedure creates a database of trim vectors and state-space matrices that are subsequently scheduled for interpolation based on engine operating point. A series of steady-state Kalman gains can next be constructed from a reduced-order form of the piecewise linear model. Reduction of the piecewise linear model to an observable dimension with respect to available sensed engine measurements can be achieved using either a subset or an optimal linear combination of "health" parameters, which describe engine performance. The resulting piecewise linear Kalman filter is then implemented for faster-than-real-time processing of sensed engine measurements, generating outputs appropriate for trending engine performance, estimating both measured and unmeasured parameters for control purposes, and performing on-board gas-path fault diagnostics. Computational efficiency is achieved by designing multidimensional interpolation algorithms that exploit the shared scheduling of multiple trim vectors and system matrices. An example application illustrates the accuracy of a self-tuning piecewise linear Kalman filter model when applied to a nonlinear turbofan engine simulation. Additional discussions focus on the issue of transient response accuracy and the advantages of a piecewise linear Kalman filter in the context of validation and verification. The techniques described provide a framework for constructing efficient self-tuning aircraft engine models from complex nonlinear simulations.Self-tuning aircraft engine models can be applied for control and health management applications. The self-tuning feature of these models minimizes the mismatch between any given engine and the underlying engineering model describing an engine family. This paper provides details of the construction of a self-tuning engine model centered on a piecewise linear Kalman filter design. Starting from a nonlinear transient aerothermal model, a piecewise linear representation is first extracted. The linearization procedure creates a database of trim vectors and state-space matrices that are subsequently scheduled for interpolation based on engine operating point. A series of steady-state Kalman gains can next be constructed from a reduced-order form of the piecewise linear model. Reduction of the piecewise linear model to an observable dimension with respect to available sensed engine measurements can be achieved using either a subset or an optimal linear combination of "health" parameters, which describe engine performance. The resulting piecewise linear Kalman filter is then implemented for faster-than-real-time processing of sensed engine measurements, generating outputs appropriate for trending engine performance, estimating both measured and unmeasured parameters for control purposes, and performing on-board gas-path fault diagnostics. Computational efficiency is achieved by designing multidimensional interpolation algorithms that exploit the shared scheduling of multiple trim vectors and system matrices. An example application illustrates the accuracy of a self-tuning piecewise linear Kalman filter model when applied to a nonlinear turbofan engine simulation. Additional discussions focus on the issue of transient response accuracy and the advantages of a piecewise linear Kalman filter in the context of validation and verification. The techniques described provide a framework for constructing efficient self-tuning aircraft engine models from complex nonlinear simulatns.

Ultra-light weight undamped tuned dynamic absorber for cryogenically cooled infrared electro-optic payload

NASA Astrophysics Data System (ADS)

Veprik, Alexander; Babitsky, Vladimir

2017-04-01

Attenuation of tonal cryocooler induced vibration in infrared electro-optical payloads may be achieved by using of Tuned Dynamic Absorber (TDA) which is, generally speaking, a passive, weakly damped mass-spring system the resonant frequency of which is precisely matched with the driving frequency. Added TDA results in a favorable modification of the frequency response functions of combined structure. In particular, a favorable antiresonant notch appears at the frequency of tonal excitation along with the adjacent secondary resonance, the width and depth of which along with its closeness to the secondary resonance are strongly dependent on the mass and damping ratios. Using heavier TDA favorably results in wider and deeper antiresonant notch along with increased gap between antiresonant and resonant frequencies. Lowering damping in TDA favorably results in deepening the antiresonant notch. The weight of TDA is usually subjected to tight design constrains. Use of lightweight TDA not only diminishes the attainable performance but also complicates the procedure of frequency matching. Along these lines, even minor frequency deviations may negate the TDA performance and even result in TDA failure in case of resonant build up. The authors are presenting theoretical and practical aspects of designing and constructing ultra-light weight TDA in application to vibration attenuation of electro-optical infrared payload relying on Split Stirling linear cryocooler, the driving frequency of which is fixed and may be accurately tuned and maintained using a digital controller over the entire range of working conditions and lifetime; the lack of mass ratio is compensated by minimizing the damping ratio. In one particular case, in excess of 100-fold vibration attenuation has been achieved by adding as little as 5% to the payload weight.

Tuned Normalization Explains the Size of Attention Modulations

PubMed Central

Ni, Amy M.; Ray, Supratim; Maunsell, John H. R.

2012-01-01

SUMMARY The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron’s receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the non-preferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. PMID:22365552

Effectiveness of multi tuned liquid dampers with slat screens for reducing dynamic responses of structures

NASA Astrophysics Data System (ADS)

Nguyen, T. P.; Pham, D. T.; Ngo, K. T.

2018-04-01

Reducing vibration in structures under lateral load always attracts many researchers in during pastime, hence the mainly purpose of paper analyzes effectiveness of multiple-tuned liquid dampers for reducing dynamic responses of structures under ground acceleration of earthquakes. In this study, the multi-tuned liquid damper with slat screens (M-TLDWSS) is considered in detail for analyzing dynamic response of multi-degrees of freedom structure due to earthquake, which is more different previous studies. Then, the general equation of motion of the structure and M-TLDWSS under ground acceleration of earthquake is established based on dynamic balance of principle and solved by numerical method in the time domain. The effects of characteristic parameters of M-TLDWSS on dynamic response of the structure are investigated. The results obtained in this study demonstrate that the M-TLDWSS has significantly effectiveness for reducing dynamic response of the structure.

Electron beam control for barely separated beams

DOEpatents

Douglas, David R.; Ament, Lucas J. P.

2017-04-18

A method for achieving independent control of multiple beams in close proximity to one another, such as in a multi-pass accelerator where coaxial beams are at different energies, but moving on a common axis, and need to be split into spatially separated beams for efficient recirculation transport. The method for independent control includes placing a magnet arrangement in the path of the barely separated beams with the magnet arrangement including at least two multipole magnets spaced closely together and having a multipole distribution including at least one odd multipole and one even multipole. The magnetic fields are then tuned to cancel out for a first of the barely separated beams to allow independent control of the second beam with common magnets. The magnetic fields may be tuned to cancel out either the dipole component or tuned to cancel out the quadrupole component in order to independently control the separate beams.

Experimental verification of a real-time tuning method of a model-based controller by perturbations to its poles

NASA Astrophysics Data System (ADS)

Kajiwara, Itsuro; Furuya, Keiichiro; Ishizuka, Shinichi

2018-07-01

Model-based controllers with adaptive design variables are often used to control an object with time-dependent characteristics. However, the controller's performance is influenced by many factors such as modeling accuracy and fluctuations in the object's characteristics. One method to overcome these negative factors is to tune model-based controllers. Herein we propose an online tuning method to maintain control performance for an object that exhibits time-dependent variations. The proposed method employs the poles of the controller as design variables because the poles significantly impact performance. Specifically, we use the simultaneous perturbation stochastic approximation (SPSA) to optimize a model-based controller with multiple design variables. Moreover, a vibration control experiment of an object with time-dependent characteristics as the temperature is varied demonstrates that the proposed method allows adaptive control and stably maintains the closed-loop characteristics.

Tuning Liposome Membrane Permeability by Competitive Peptide Dimerization and Partitioning-Folding Interactions Regulated by Proteolytic Activity

NASA Astrophysics Data System (ADS)

Lim, Seng Koon; Sandén, Camilla; Selegård, Robert; Liedberg, Bo; Aili, Daniel

2016-02-01

Membrane active peptides are of large interest for development of drug delivery vehicles and therapeutics for treatment of multiple drug resistant infections. Lack of specificity can be detrimental and finding routes to tune specificity and activity of membrane active peptides is vital for improving their therapeutic efficacy and minimize harmful side effects. We describe a de novo designed membrane active peptide that partition into lipid membranes only when specifically and covalently anchored to the membrane, resulting in pore-formation. Dimerization with a complementary peptide efficiently inhibits formation of pores. The effect can be regulated by proteolytic digestion of the inhibitory peptide by the matrix metalloproteinase MMP-7, an enzyme upregulated in many malignant tumors. This system thus provides a precise and specific route for tuning the permeability of lipid membranes and a novel strategy for development of recognition based membrane active peptides and indirect enzymatically controlled release of liposomal cargo.

Tuned normalization explains the size of attention modulations.

PubMed

Ni, Amy M; Ray, Supratim; Maunsell, John H R

2012-02-23

The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron's receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the nonpreferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. Copyright © 2012 Elsevier Inc. All rights reserved.

Controlling Reaction Selectivity through the Surface Termination of Perovskite Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polo-Garzon, Felipe; Yang, Shi-Ze; Fung, Victor

2017-07-19

Although perovskites have been widely used in catalysis, tuning their surface terminations to control reaction selectivities has not been well established. In this work, we employ multiple surface sensitive techniques to characterize the surface termination (one aspect of surface reconstruction) of SrTiO 3 (STO) after thermal pretreatment (Sr-enrichment) and chemical etching (Ti-enrichment). We show, using the conversion of 2-propanol as a probe reaction, that the surface termination of STO can be controlled to greatly tune catalytic acid/base properties and consequently the reaction selectivities in a wide range, which are inaccessible using single metal oxides, either SrO or TiO 2. Densitymore » functional theory (DFT) calculations well explain the selectivity tuning and reaction mechanism on different surface terminations of STO. Similar catalytic tunability is also observed on BaZrO 3, highlighting the generality of the finding from this work.« less

Recurrent competition explains temporal effects of attention in MSTd

PubMed Central

Layton, Oliver W.; Browning, N. Andrew

2012-01-01

Navigation in a static environment along straight paths without eye movements produces radial optic flow fields. A singularity called the focus of expansion (FoE) specifies the direction of travel (heading) of the observer. Cells in primate dorsal medial superior temporal area (MSTd) respond to radial fields and are therefore thought to be heading-sensitive. Humans frequently shift their focus of attention while navigating, for example, depending on the favorable or threatening context of approaching independently moving objects. Recent neurophysiological studies show that the spatial tuning curves of primate MSTd neurons change based on the difference in visual angle between an attentional prime and the FoE. Moreover, the peak mean population activity in MSTd retreats linearly in time as the distance between the attentional prime and FoE increases. We present a dynamical neural circuit model that demonstrates the same linear temporal peak shift observed electrophysiologically. The model qualitatively matches the neuron tuning curves and population activation profiles. After model MT dynamically pools short-range motion, model MSTd incorporates recurrent competition between units tuned to different radial optic flow templates, and integrates attentional signals from model area frontal eye fields (FEF). In the model, population activity peaks occur when the recurrent competition is most active and uncertainty is greatest about the relative position of the FoE. The nature of attention, multiplicative or non-multiplicative, is largely irrelevant, so long as attention has a Gaussian-like profile. Using an appropriately tuned sigmoidal signal function to modulate recurrent feedback affords qualitative fits of deflections in the population activity that otherwise appear to be low-frequency noise. We predict that these deflections mark changes in the balance of attention between the priming and FoE locations. PMID:23060788

Bayesian LASSO, scale space and decision making in association genetics.

PubMed

Pasanen, Leena; Holmström, Lasse; Sillanpää, Mikko J

2015-01-01

LASSO is a penalized regression method that facilitates model fitting in situations where there are as many, or even more explanatory variables than observations, and only a few variables are relevant in explaining the data. We focus on the Bayesian version of LASSO and consider four problems that need special attention: (i) controlling false positives, (ii) multiple comparisons, (iii) collinearity among explanatory variables, and (iv) the choice of the tuning parameter that controls the amount of shrinkage and the sparsity of the estimates. The particular application considered is association genetics, where LASSO regression can be used to find links between chromosome locations and phenotypic traits in a biological organism. However, the proposed techniques are relevant also in other contexts where LASSO is used for variable selection. We separate the true associations from false positives using the posterior distribution of the effects (regression coefficients) provided by Bayesian LASSO. We propose to solve the multiple comparisons problem by using simultaneous inference based on the joint posterior distribution of the effects. Bayesian LASSO also tends to distribute an effect among collinear variables, making detection of an association difficult. We propose to solve this problem by considering not only individual effects but also their functionals (i.e. sums and differences). Finally, whereas in Bayesian LASSO the tuning parameter is often regarded as a random variable, we adopt a scale space view and consider a whole range of fixed tuning parameters, instead. The effect estimates and the associated inference are considered for all tuning parameters in the selected range and the results are visualized with color maps that provide useful insights into data and the association problem considered. The methods are illustrated using two sets of artificial data and one real data set, all representing typical settings in association genetics.

Quantum vacuum energy in general relativity

NASA Astrophysics Data System (ADS)

Henke, Christian

2018-02-01

The paper deals with the scale discrepancy between the observed vacuum energy in cosmology and the theoretical quantum vacuum energy (cosmological constant problem). Here, we demonstrate that Einstein's equation and an analogy to particle physics leads to the first physical justification of the so-called fine-tuning problem. This fine-tuning could be automatically satisfied with the variable cosmological term Λ (a)=Λ_0+Λ_1 a^{-(4-ɛ)}, 0 < ɛ ≪ 1, where a is the scale factor. As a side effect of our solution of the cosmological constant problem, the dynamical part of the cosmological term generates an attractive force and solves the missing mass problem of dark matter.

The anatomy of a launch vehicle : quarterly report topic

DOT National Transportation Integrated Search

2001-01-01

Conceptually, a rocket is a simple machine. Following Newton's law that every force has an equal and opposite reaction, a rocket pushes mass in one direction and moves in the other. However, a modern space launch vehicle is a finely tuned and very co...

Multiple binding sites for transcriptional repressors can produce regular bursting and enhance noise suppression

NASA Astrophysics Data System (ADS)

Lengyel, Iván M.; Morelli, Luis G.

2017-04-01

Cells may control fluctuations in protein levels by means of negative autoregulation, where transcription factors bind DNA sites to repress their own production. Theoretical studies have assumed a single binding site for the repressor, while in most species it is found that multiple binding sites are arranged in clusters. We study a stochastic description of negative autoregulation with multiple binding sites for the repressor. We find that increasing the number of binding sites induces regular bursting of gene products. By tuning the threshold for repression, we show that multiple binding sites can also suppress fluctuations. Our results highlight possible roles for the presence of multiple binding sites of negative autoregulators.

Fully integrated aerodynamic/dynamic optimization of helicopter rotor blades

NASA Technical Reports Server (NTRS)

Walsh, Joanne L.; Lamarsh, William J., II; Adelman, Howard M.

1992-01-01

This paper describes a fully integrated aerodynamic/dynamic optimization procedure for helicopter rotor blades. The procedure combines performance and dynamics analyses with a general purpose optimizer. The procedure minimizes a linear combination of power required (in hover, forward flight, and maneuver) and vibratory hub shear. The design variables include pretwist, taper initiation, taper ratio, root chord, blade stiffnesses, tuning masses, and tuning mass locations. Aerodynamic constraints consist of limits on power required in hover, forward flight and maneuver; airfoil section stall; drag divergence Mach number; minimum tip chord; and trim. Dynamic constraints are on frequencies, minimum autorotational inertia, and maximum blade weight. The procedure is demonstrated for two cases. In the first case the objective function involves power required (in hover, forward flight, and maneuver) and dynamics. The second case involves only hover power and dynamics. The designs from the integrated procedure are compared with designs from a sequential optimization approach in which the blade is first optimized for performance and then for dynamics. In both cases, the integrated approach is superior.

Fully integrated aerodynamic/dynamic optimization of helicopter rotor blades

NASA Technical Reports Server (NTRS)

Walsh, Joanne L.; Lamarsh, William J., II; Adelman, Howard M.

1992-01-01

A fully integrated aerodynamic/dynamic optimization procedure is described for helicopter rotor blades. The procedure combines performance and dynamic analyses with a general purpose optimizer. The procedure minimizes a linear combination of power required (in hover, forward flight, and maneuver) and vibratory hub shear. The design variables include pretwist, taper initiation, taper ratio, root chord, blade stiffnesses, tuning masses, and tuning mass locations. Aerodynamic constraints consist of limits on power required in hover, forward flight and maneuvers; airfoil section stall; drag divergence Mach number; minimum tip chord; and trim. Dynamic constraints are on frequencies, minimum autorotational inertia, and maximum blade weight. The procedure is demonstrated for two cases. In the first case, the objective function involves power required (in hover, forward flight and maneuver) and dynamics. The second case involves only hover power and dynamics. The designs from the integrated procedure are compared with designs from a sequential optimization approach in which the blade is first optimized for performance and then for dynamics. In both cases, the integrated approach is superior.

Natural Scherk-Schwarz theories of the weak scale

DOE PAGES

García, Isabel Garcia; Howe, Kiel; March-Russell, John

2015-12-01

Natural supersymmetric theories of the weak scale are under growing pressure given present LHC constraints, raising the question of whether untuned supersymmetric (SUSY) solutions to the hierarchy problem are possible. In this paper, we explore a class of 5-dimensional natural SUSY theories in which SUSY is broken by the Scherk-Schwarz mechanism. We pedagogically explain how Scherk-Schwarz elegantly solves the traditional problems of 4-dimensional SUSY theories (based on the MSSM and its many variants) that usually result in an unsettling level of fine-tuning. The minimal Scherk-Schwarz set up possesses novel phenomenology, which we briefly outline. In this study, we show thatmore » achieving the observed physical Higgs mass motivates extra structure that does not significantly affect the level of tuning (always better than ~10%) and we explore three qualitatively different extensions: the addition of extra matter that couples to the Higgs, an extra U(1)' gauge group under which the Higgs is charged and an NMSSM-like solution to the Higgs mass problem.« less

Electromagnetic energy coupling mechanism with matrix architecture control

NASA Technical Reports Server (NTRS)

Hughes, Eli (Inventor); Knowles, Gareth (Inventor)

2006-01-01

The present invention relates generally to reconfigurable, solid-state matrix arrays comprising multiple rows and columns of reconfigurable secondary mechanisms that are independently tuned. Specifically, the invention relates to reconfigurable devices comprising multiple, solid-state mechanisms characterized by at least one voltage-varied parameter disposed within a flexible, multi-laminate film, which are suitable for use as magnetic conductors, ground surfaces, antennas, varactors, ferrotunable substrates, or other active or passive electronic mechanisms.

Coherent direct sequence optical code multiple access encoding-decoding efficiency versus wavelength detuning.

PubMed

Pastor, D; Amaya, W; García-Olcina, R; Sales, S

2007-07-01

We present a simple theoretical model of and the experimental verification for vanishing of the autocorrelation peak due to wavelength detuning on the coding-decoding process of coherent direct sequence optical code multiple access systems based on a superstructured fiber Bragg grating. Moreover, the detuning vanishing effect has been explored to take advantage of this effect and to provide an additional degree of multiplexing and/or optical code tuning.

SO(10) Yukawa unification: SUSY on the edge

NASA Astrophysics Data System (ADS)

Raby, Stuart

2016-06-01

In this talk we discuss SO(10) Yukawa unification and its ramifications for phenomenology. The initial constraints come from fitting the top, bottom and tau masses, requiring large tan β ~ 50 and particular values for soft SUSY breaking parameters. We perform a global χ2 analysis, fitting the recently observed `Higgs' with mass of order 125 GeV in addition to fermion masses and mixing angles and several flavor violating observables. We discuss two distinct GUT scale boundary conditions for soft SUSY breaking masses. In both cases we have a universal cubic scalar parameter, A0, non-universal Higgs masses and universal squark and slepton masses, m16. In the first case we consider universal gaugino masses, while in the latter case we have non-universal gaugino masses. We discuss the spectrum of SUSY particle masses, consequences for the LHC and the issue of fine-tuning.

Mass Protection via Translational Invariance

NASA Astrophysics Data System (ADS)

Alonso, José Luis; Cortés, José Luis; Boucaud, Philippe; Carmona, José Manuel; Polonyi, Janos; Sijs, Arjan Van Der

We propose a way of protecting a Dirac fermion interacting with a scalar field from acquiring a mass from the vacuum. It is obtained through an implementation of translational symmetry when the theory is formulated with a momentum cutoff, which forbids the usual Yukawa term. We consider that this mechanism can help to understand the smallness of neutrino masses without a tuning of the Yukawa coupling. The prohibition of the Yukawa term for the neutrino forbids at the same time a gauge coupling between the right-handed electron and neutrino. We prove that this mechanism can be implemented on the lattice.

A new mechanism of mass protection for fermions

NASA Astrophysics Data System (ADS)

Alonso, J. L.; Boucaud, Ph.; Carmona, J. M.; Cortés, J. L.; Polonyi, J.; van der Sijs, A. J.

We present a way of protecting a Dirac fermion interacting with a scalar (Higgs) field from getting a mass from the vacuum. It is obtained through an implementation of translational symmetry when the theory is formulated with a momentum cutoff, which forbids the usual Yukawa term. We consider that this mechanism can help to understand the smallness of neutrino masses without a tuning of the Yukawa coupling. The prohibition of the Yukawa term for the neutrino forbids at the same time a gauge coupling between the right-handed electron and neutrino. We prove that this mechanism can be implemented on the lattice.

Electron mass in dilute nitrides and its anomalous dependence on hydrostatic pressure.

PubMed

Pettinari, G; Polimeni, A; Masia, F; Trotta, R; Felici, M; Capizzi, M; Niebling, T; Stolz, W; Klar, P J

2007-04-06

The dependence of the electron mass on hydrostatic pressure P in N-diluted GaAs1-xNx (x=0.10% and 0.21%) is investigated by magnetophotoluminescence. Exceedingly large fluctuations (up to 60%/kbar) in the electron mass with increasing P are found. These originate from a pressure-driven tuning of the hybridization degree between the conduction band minimum and specific nitrogen-related states. Present results suggest a hierarchy between different nitrogen complexes as regards the extent of the perturbation these complexes exert on the electronic properties of the GaAs host.

The Fine-Tuning of the Universe for Intelligent Life

NASA Astrophysics Data System (ADS)

Barnes, L. A.

2012-06-01

The fine-tuning of the universe for intelligent life has received a great deal of attention in recent years, both in the philosophical and scientific literature. The claim is that in the space of possible physical laws, parameters and initial conditions, the set that permits the evolution of intelligent life is very small. I present here a review of the scientific literature, outlining cases of fine-tuning in the classic works of Carter, Carr and Rees, and Barrow and Tipler, as well as more recent work. To sharpen the discussion, the role of the antagonist will be played by Victor Stenger's recent book The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us. Stenger claims that all known fine-tuning cases can be explained without the need for a multiverse. Many of Stenger's claims will be found to be highly problematic. We will touch on such issues as the logical necessity of the laws of nature; objectivity, invariance and symmetry; theoretical physics and possible universes; entropy in cosmology; cosmic inflation and initial conditions; galaxy formation; the cosmological constant; stars and their formation; the properties of elementary particles and their effect on chemistry and the macroscopic world; the origin of mass; grand unified theories; and the dimensionality of space and time. I also provide an assessment of the multiverse, noting the significant challenges that it must face. I do not attempt to defend any conclusion based on the fine-tuning of the universe for intelligent life. This paper can be viewed as a critique of Stenger's book, or read independently.

Development of Tuning Fork Based Probes for Atomic Force Microscopy

NASA Astrophysics Data System (ADS)

Jalilian, Romaneh; Yazdanpanah, Mehdi M.; Torrez, Neil; Alizadeh, Amirali; Askari, Davood

2014-03-01

This article reports on the development of tuning fork-based AFM/STM probes in NaugaNeedles LLC for use in atomic force microscopy. These probes can be mounted on different carriers per customers' request. (e.g., RHK carrier, Omicron carrier, and tuning fork on a Sapphire disk). We are able to design and engineer tuning forks on any type of carrier used in the market. We can attach three types of tips on the edge of a tuning fork prong (i.e., growing Ag2Ga nanoneedles at any arbitrary angle, cantilever of AFM tip, and tungsten wire) with lengths from 100-500 μm. The nanoneedle is located vertical to the fork. Using a suitable insulation and metallic coating, we can make QPlus sensors that can detect tunneling current during the AFM scan. To make Qplus sensors, the entire quartz fork will be coated with an insulating material, before attaching the nanoneedle. Then, the top edge of one prong is coated with a thin layer of conductive metal and the nanoneedle is attached to the fork end of the metal coated prong. The metal coating provides electrical connection to the tip for tunneling current readout and to the electrodes and used to read the QPlus current. Since the amount of mass added to the fork is minimal, the resonance frequency spectrum does not change and still remains around 32.6 KHz and the Q factor is around 1,200 in ambient condition. These probes can enhance the performance of tuning fork based atomic microscopy.

Multiple-Point Temperature Gradient Algorithm for Ring Laser Gyroscope Bias Compensation

PubMed Central

Li, Geng; Zhang, Pengfei; Wei, Guo; Xie, Yuanping; Yu, Xudong; Long, Xingwu

2015-01-01

To further improve ring laser gyroscope (RLG) bias stability, a multiple-point temperature gradient algorithm is proposed for RLG bias compensation in this paper. Based on the multiple-point temperature measurement system, a complete thermo-image of the RLG block is developed. Combined with the multiple-point temperature gradients between different points of the RLG block, the particle swarm optimization algorithm is used to tune the support vector machine (SVM) parameters, and an optimized design for selecting the thermometer locations is also discussed. The experimental results validate the superiority of the introduced method and enhance the precision and generalizability in the RLG bias compensation model. PMID:26633401

Self-tuning control algorithm design for vehicle adaptive cruise control system through real-time estimation of vehicle parameters and road grade

NASA Astrophysics Data System (ADS)

Marzbanrad, Javad; Tahbaz-zadeh Moghaddam, Iman

2016-09-01

The main purpose of this paper is to design a self-tuning control algorithm for an adaptive cruise control (ACC) system that can adapt its behaviour to variations of vehicle dynamics and uncertain road grade. To this aim, short-time linear quadratic form (STLQF) estimation technique is developed so as to track simultaneously the trend of the time-varying parameters of vehicle longitudinal dynamics with a small delay. These parameters are vehicle mass, road grade and aerodynamic drag-area coefficient. Next, the values of estimated parameters are used to tune the throttle and brake control inputs and to regulate the throttle/brake switching logic that governs the throttle and brake switching. The performance of the designed STLQF-based self-tuning control (STLQF-STC) algorithm for ACC system is compared with the conventional method based on fixed control structure regarding the speed/distance tracking control modes. Simulation results show that the proposed control algorithm improves the performance of throttle and brake controllers, providing more comfort while travelling, enhancing driving safety and giving a satisfactory performance in the presence of different payloads and road grade variations.

Oxygen Vacancy-Tuned Physical Properties in Perovskite Thin Films with Multiple B-site Valance States

DOE PAGES

Enriquez, Erik; Chen, Aiping; Harrell, Zach; ...

2017-04-18

Controlling oxygen content in perovskite oxides with ABO 3 structure is one of most critical steps for tuning their functionality. Notably, there have been tremendous efforts to understand the effect of changes in oxygen content on the properties of perovskite thin films that are not composed of cations with multiple valance states. Here, we study the effect of oxygen vacancies on structural and electrical properties in epitaxial thin films of SrFeO 3-δ (SFO), where SFO is a compound with multiple valance states at the B site. Various annealing treatments are used to produce different oxygen contents in the films, whichmore » has resulted in significant structural changes in the fully strained SFO films. The out-of-plane lattice parameter and tetragonality increase with decreasing oxygen concentration, indicating the crystal structure is closely related to the oxygen content. Importantly, variation of the oxygen content in the films significantly affects the dielectric properties, leakage conduction mechanisms, and the resistive hysteresis of the materials. These results establish the relationship between oxygen content and structural and functional properties for a range of multivalent transition metal oxides.« less

Oxygen Vacancy-Tuned Physical Properties in Perovskite Thin Films with Multiple B-site Valance States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enriquez, Erik; Chen, Aiping; Harrell, Zach

Controlling oxygen content in perovskite oxides with ABO 3 structure is one of most critical steps for tuning their functionality. Notably, there have been tremendous efforts to understand the effect of changes in oxygen content on the properties of perovskite thin films that are not composed of cations with multiple valance states. Here, we study the effect of oxygen vacancies on structural and electrical properties in epitaxial thin films of SrFeO 3-δ (SFO), where SFO is a compound with multiple valance states at the B site. Various annealing treatments are used to produce different oxygen contents in the films, whichmore » has resulted in significant structural changes in the fully strained SFO films. The out-of-plane lattice parameter and tetragonality increase with decreasing oxygen concentration, indicating the crystal structure is closely related to the oxygen content. Importantly, variation of the oxygen content in the films significantly affects the dielectric properties, leakage conduction mechanisms, and the resistive hysteresis of the materials. These results establish the relationship between oxygen content and structural and functional properties for a range of multivalent transition metal oxides.« less

Ultrafast frequency-agile terahertz devices using methylammonium lead halide perovskites

PubMed Central

Chanana, Ashish; Liu, Xiaojie; Vardeny, Zeev Valy

2018-01-01

The ability to control the response of metamaterial structures can facilitate the development of new terahertz devices, with applications in spectroscopy and communications. We demonstrate ultrafast frequency-agile terahertz metamaterial devices that enable such a capability, in which multiple perovskites can be patterned in each unit cell with micrometer-scale precision. To accomplish this, we developed a fabrication technique that shields already deposited perovskites from organic solvents, allowing for multiple perovskites to be patterned in close proximity. By doing so, we demonstrate tuning of the terahertz resonant response that is based not only on the optical pump fluence but also on the optical wavelength. Because polycrystalline perovskites have subnanosecond photocarrier recombination lifetimes, switching between resonances can occur on an ultrafast time scale. The use of multiple perovskites allows for new functionalities that are not possible using a single semiconducting material. For example, by patterning one perovskite in the gaps of split-ring resonators and bringing a uniform thin film of a second perovskite in close proximity, we demonstrate tuning of the resonant response using one optical wavelength and suppression of the resonance using a different optical wavelength. This general approach offers new capabilities for creating tunable terahertz devices. PMID:29736416

Ultrafast frequency-agile terahertz devices using methylammonium lead halide perovskites.

PubMed

Chanana, Ashish; Liu, Xiaojie; Zhang, Chuang; Vardeny, Zeev Valy; Nahata, Ajay

2018-05-01

The ability to control the response of metamaterial structures can facilitate the development of new terahertz devices, with applications in spectroscopy and communications. We demonstrate ultrafast frequency-agile terahertz metamaterial devices that enable such a capability, in which multiple perovskites can be patterned in each unit cell with micrometer-scale precision. To accomplish this, we developed a fabrication technique that shields already deposited perovskites from organic solvents, allowing for multiple perovskites to be patterned in close proximity. By doing so, we demonstrate tuning of the terahertz resonant response that is based not only on the optical pump fluence but also on the optical wavelength. Because polycrystalline perovskites have subnanosecond photocarrier recombination lifetimes, switching between resonances can occur on an ultrafast time scale. The use of multiple perovskites allows for new functionalities that are not possible using a single semiconducting material. For example, by patterning one perovskite in the gaps of split-ring resonators and bringing a uniform thin film of a second perovskite in close proximity, we demonstrate tuning of the resonant response using one optical wavelength and suppression of the resonance using a different optical wavelength. This general approach offers new capabilities for creating tunable terahertz devices.

Comparison of the protein-coding genomes of three deep-sea, sulfur-oxidising bacteria: "Candidatus Ruthia magnifica", "Candidatus Vesicomyosocius okutanii" and Thiomicrospira crunogena.

PubMed

McGill, Susan E; Barker, Daniel

2017-07-20

" Candidatus Ruthia magnifica", "Candidatus Vesicomyosocius okutanii" and Thiomicrospira crunogena are all sulfur-oxidising bacteria found in deep-sea vent environments. Recent research suggests that the two symbiotic organisms, "Candidatus R. magnifica" and "Candidatus V. okutanii", may share common ancestry with the autonomously living species T. crunogena. We used comparative genomics to examine the genome-wide protein-coding content of all three species to explore their similarities. In particular, we used the OrthoMCL algorithm to sort proteins into groups of putative orthologs on the basis of sequence similarity. The OrthoMCL inflation parameter was tuned using biological criteria. Using the tuned value, OrthoMCL delimited 1070 protein groups. 63.5% of these groups contained one protein from each species. Two groups contained duplicate protein copies from all three species. 123 groups were unique to T. crunogena and ten groups included multiple copies of T. crunogena proteins but only single copies from the other species. "Candidatus R. magnifica" had one unique group, and had multiple copies in one group where the other species had a single copy. There were no groups unique to "Candidatus V. okutanii", and no groups in which there were multiple "Candidatus V. okutanii" proteins but only single proteins from the other species. Results align with previous suggestions that all three species share a common ancestor. However this is not definitive evidence to make taxonomic conclusions and the possibility of horizontal gene transfer was not investigated. Methodologically, the tuning of the OrthoMCL inflation parameter using biological criteria provides further methods to refine the OrthoMCL procedure.

A distinct layer of the medulla integrates sky compass signals in the brain of an insect.

PubMed

el Jundi, Basil; Pfeiffer, Keram; Homberg, Uwe

2011-01-01

Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu.

A Distinct Layer of the Medulla Integrates Sky Compass Signals in the Brain of an Insect

PubMed Central

el Jundi, Basil; Pfeiffer, Keram; Homberg, Uwe

2011-01-01

Mass migration of desert locusts is a common phenomenon in North Africa and the Middle East but how these insects navigate is still poorly understood. Laboratory studies suggest that locusts are able to exploit the sky polarization pattern as a navigational cue. Like other insects locusts detect polarized light through a specialized dorsal rim area (DRA) of the eye. Polarization signals are transmitted through the optic lobe to the anterior optic tubercle (AOTu) and, finally, to the central complex in the brain. Whereas neurons of the AOTu integrate sky polarization and chromatic cues in a daytime dependent manner, the central complex holds a topographic representation of azimuthal directions suggesting a role as an internal sky compass. To understand further the integration of sky compass cues we studied polarization-sensitive (POL) neurons in the medulla that may be intercalated between DRA photoreceptors and AOTu neurons. Five types of POL-neuron were characterized and four of these in multiple recordings. All neurons had wide arborizations in medulla layer 4 and most, additionally, in the dorsal rim area of the medulla and in the accessory medulla, the presumed circadian clock. The neurons showed type-specific orientational tuning to zenithal polarized light and azimuth tuning to unpolarized green and UV light spots. In contrast to neurons of the AOTu, we found no evidence for color opponency and daytime dependent adjustment of sky compass signals. Therefore, medulla layer 4 is a distinct stage in the integration of sky compass signals that precedes the time-compensated integration of celestial cues in the AOTu. PMID:22114712

Astronomical calibration of 40Ar/39Ar reference minerals using high-precision, multi-collector (ARGUSVI) mass spectrometry

NASA Astrophysics Data System (ADS)

Phillips, D.; Matchan, E. L.; Honda, M.; Kuiper, K. F.

2017-01-01

The new generation of multi-collector mass spectrometers (e.g. ARGUSVI) permit ultra-high precision (<0.1%) 40Ar/39Ar geochronology of rocks and minerals. At the same time, the 40Ar/39Ar method is limited by relatively large uncertainties (>1%) in 40K decay constants and the ages of natural reference minerals that form the basis of the technique. For example, reported ages for widely used 40Ar/39Ar reference materials, such as the ca. 28 Ma Fish Canyon Tuff sanidine (FCTs) and the ca. 1.2 Ma Alder Creek Rhyolite sanidine (ACRs), vary by >1%. Recent attempts to independently calibrate these reference minerals have focused on K-Ar analyses of the same minerals and inter-comparisons with astronomically tuned tephras in sedimentary sequences and U-Pb zircon ages from volcanic rocks. Most of these studies used older generation (effectively single-collector) mass spectrometers that employed peak-jumping analytical methods to acquire 40Ar/39Ar data. In this study, we reassess the inter-calibration and ages of commonly used 40Ar/39Ar reference minerals Fish Canyon Tuff sanidine (FCTs), Alder Creek Rhyolite sanidine (ACRs) and Mount Dromedary biotite (MD2b; equivalent to GA-1550 biotite), relative to the astronomically tuned age of A1 Tephra sanidine (A1Ts), Faneromeni section, Crete (Rivera et al., 2011), using a multi-collector ARGUSVI mass spectrometer. These analyses confirm the exceptional precision capability (<0.1%) of this system, compared to most previous studies. All sanidine samples (FCTs, ACRs and A1Ts) exhibit discordant 40Ar/39Ar step-heating spectra, with generally monotonically increasing ages (∼1% gradients). The similarity in these patterns, mass-dependent fractionation modeling, and results from step-crushing experiments on FCTs, which yield younger apparent ages, suggest that the discordance may be due to a combination of recoil loss and redistribution of 39ArK and isotope mass fractionation. In contrast to our previous inferences, these results imply that the sanidine samples are suitable 40Ar/39Ar reference materials, provided appropriate corrections are included for differential recoil loss of 39ArK and contributions from xenocrysts/antecrysts can be resolved. Relative to an age of 6.943 ± 0.005 Ma for A1Ts, we calculate astronomically tuned ages for FCTs, ACRs and MD2b of 28.126 ± 0.019 (0.066%) Ma, 1.18144 ± 0.00068 (0.058%) Ma and 99.125 ± 0.076 (0.077%) Ma, respectively (95% internal errors). These results are consistent with recent 238U/206Pb age data from these localities, but are marginally younger (∼0.2%) than previous 40Ar/39Ar ages inter-calibrated with astronomically tuned tephra from the Mediterranean, and distinctly younger (0.6%) than results optimized against a broad array of 238U/206Pb zircon ages. Consideration of published and assumed recoil loss 39ArK proportions (0.18-0.40%), yields recoil-corrected age estimates of 28.187 ± 0.019 Ma, 1.18404 ± 0.00068 Ma and 99.204 ± 0.076 Ma, respectively. This comparison indicates inherent uncertainties of >0.1% in the 40Ar/39Ar ages of reference minerals without consideration of recoil artefacts, thus limiting the benefits of high precision multi-collector analyses. Significant improvement to the accuracy of the 40Ar/39Ar method (<0.1%) will require further inter-laboratory 40Ar/39Ar studies utilizing multi-collector mass spectrometry, additional constraints on recoil 39ArK loss from reference minerals, further resolution of discrepancies between astronomically tuned sedimentary successions and refinement of the 238U/206Pb zircon age cross-calibration approach.

Trajectory following and stabilization control of fully actuated AUV using inverse kinematics and self-tuning fuzzy PID.

PubMed

Hammad, Mohanad M; Elshenawy, Ahmed K; El Singaby, M I

2017-01-01

In this work a design for self-tuning non-linear Fuzzy Proportional Integral Derivative (FPID) controller is presented to control position and speed of Multiple Input Multiple Output (MIMO) fully-actuated Autonomous Underwater Vehicles (AUV) to follow desired trajectories. Non-linearity that results from the hydrodynamics and the coupled AUV dynamics makes the design of a stable controller a very difficult task. In this study, the control scheme in a simulation environment is validated using dynamic and kinematic equations for the AUV model and hydrodynamic damping equations. An AUV configuration with eight thrusters and an inverse kinematic model from a previous work is utilized in the simulation. In the proposed controller, Mamdani fuzzy rules are used to tune the parameters of the PID. Nonlinear fuzzy Gaussian membership functions are selected to give better performance and response in the non-linear system. A control architecture with two feedback loops is designed such that the inner loop is for velocity control and outer loop is for position control. Several test scenarios are executed to validate the controller performance including different complex trajectories with and without injection of ocean current disturbances. A comparison between the proposed FPID controller and the conventional PID controller is studied and shows that the FPID controller has a faster response to the reference signal and more stable behavior in a disturbed non-linear environment.

Trajectory following and stabilization control of fully actuated AUV using inverse kinematics and self-tuning fuzzy PID

PubMed Central

Elshenawy, Ahmed K.; El Singaby, M.I.

2017-01-01

In this work a design for self-tuning non-linear Fuzzy Proportional Integral Derivative (FPID) controller is presented to control position and speed of Multiple Input Multiple Output (MIMO) fully-actuated Autonomous Underwater Vehicles (AUV) to follow desired trajectories. Non-linearity that results from the hydrodynamics and the coupled AUV dynamics makes the design of a stable controller a very difficult task. In this study, the control scheme in a simulation environment is validated using dynamic and kinematic equations for the AUV model and hydrodynamic damping equations. An AUV configuration with eight thrusters and an inverse kinematic model from a previous work is utilized in the simulation. In the proposed controller, Mamdani fuzzy rules are used to tune the parameters of the PID. Nonlinear fuzzy Gaussian membership functions are selected to give better performance and response in the non-linear system. A control architecture with two feedback loops is designed such that the inner loop is for velocity control and outer loop is for position control. Several test scenarios are executed to validate the controller performance including different complex trajectories with and without injection of ocean current disturbances. A comparison between the proposed FPID controller and the conventional PID controller is studied and shows that the FPID controller has a faster response to the reference signal and more stable behavior in a disturbed non-linear environment. PMID:28683071

Mechanosensation is evolutionarily tuned to locomotor mechanics

PubMed Central

Aiello, Brett R.; Westneat, Mark W.; Hale, Melina E.

2017-01-01

The biomechanics of animal limbs has evolved to meet the functional demands for movement associated with different behaviors and environments. Effective movement relies not only on limb mechanics but also on appropriate mechanosensory feedback. By comparing sensory ability and mechanics within a phylogenetic framework, we show that peripheral mechanosensation has evolved with limb biomechanics, evolutionarily tuning the neuromechanical system to its functional demands. We examined sensory physiology and mechanics of the pectoral fins, forelimb homologs, in the fish family Labridae. Labrid fishes exhibit extraordinary morphological and behavioral diversity and use pectoral fin-based propulsion with fins ranging in shape from high aspect ratio (AR) wing-like fins to low AR paddle-like fins. Phylogenetic character analysis demonstrates that high AR fins evolved independently multiple times in this group. Four pairs of species were examined; each included a plesiomorphic low AR and a high AR species. Within each species pair, the high AR species demonstrated significantly stiffer fin rays in comparison with the low AR species. Afferent sensory nerve activity was recorded during fin ray bending. In all cases, afferents of stiffer fins were more sensitive at lower displacement amplitudes, demonstrating mechanosensory tuning to fin mechanics and a consistent pattern of correlated evolution. We suggest that these data provide a clear example of parallel evolution in a complex neuromechanical system, with a strong link between multiple phenotypic characters: pectoral fin shape, swimming behavior, fin ray stiffness, and mechanosensory sensitivity. PMID:28396411

Double resonator cantilever accelerometer

DOEpatents

Koehler, Dale R.

1984-01-01

A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

Frequency Control of Single Quantum Emitters in Integrated Photonic Circuits

NASA Astrophysics Data System (ADS)

Schmidgall, Emma R.; Chakravarthi, Srivatsa; Gould, Michael; Christen, Ian R.; Hestroffer, Karine; Hatami, Fariba; Fu, Kai-Mei C.

2018-02-01

Generating entangled graph states of qubits requires high entanglement rates, with efficient detection of multiple indistinguishable photons from separate qubits. Integrating defect-based qubits into photonic devices results in an enhanced photon collection efficiency, however, typically at the cost of a reduced defect emission energy homogeneity. Here, we demonstrate that the reduction in defect homogeneity in an integrated device can be partially offset by electric field tuning. Using photonic device-coupled implanted nitrogen vacancy (NV) centers in a GaP-on-diamond platform, we demonstrate large field-dependent tuning ranges and partial stabilization of defect emission energies. These results address some of the challenges of chip-scale entanglement generation.

Frequency Control of Single Quantum Emitters in Integrated Photonic Circuits.

PubMed

Schmidgall, Emma R; Chakravarthi, Srivatsa; Gould, Michael; Christen, Ian R; Hestroffer, Karine; Hatami, Fariba; Fu, Kai-Mei C

2018-02-14

Generating entangled graph states of qubits requires high entanglement rates with efficient detection of multiple indistinguishable photons from separate qubits. Integrating defect-based qubits into photonic devices results in an enhanced photon collection efficiency, however, typically at the cost of a reduced defect emission energy homogeneity. Here, we demonstrate that the reduction in defect homogeneity in an integrated device can be partially offset by electric field tuning. Using photonic device-coupled implanted nitrogen vacancy (NV) centers in a GaP-on-diamond platform, we demonstrate large field-dependent tuning ranges and partial stabilization of defect emission energies. These results address some of the challenges of chip-scale entanglement generation.

Method for fabrication and verification of conjugated nanoparticle-antibody tuning elements for multiplexed electrochemical biosensors.

PubMed

La Belle, Jeffrey T; Fairchild, Aaron; Demirok, Ugur K; Verma, Aman

2013-05-15

There is a critical need for more accurate, highly sensitive and specific assay for disease diagnosis and management. A novel, multiplexed, single sensor using rapid and label free electrochemical impedance spectroscopy tuning method has been developed. The key challenges while monitoring multiple targets is frequency overlap. Here we describe the methods to circumvent the overlap, tune by use of nanoparticle (NP) and discuss the various fabrication and characterization methods to develop this technique. First sensors were fabricated using printed circuit board (PCB) technology and nickel and gold layers were electrodeposited onto the PCB sensors. An off-chip conjugation of gold NP's to molecular recognition elements (with verification technique) is described as well. A standard covalent immobilization of the molecular recognition elements is also discussed with quality control techniques. Finally use and verification of sensitivity and specificity is also presented. By use of gold NP's of various sizes, we have demonstrated the possibility and shown little loss of sensitivity and specificity in the molecular recognition of inflammatory markers as "model" targets for our tuning system. By selection of other sized NP's or NP's of various materials, the tuning effect can be further exploited. The novel platform technology developed could be utilized in critical care, clinical management and at home health and disease management. Copyright © 2013 Elsevier Inc. All rights reserved.

Neutrino mass, dark matter, and Baryon asymmetry via TeV-scale physics without fine-tuning.

PubMed

Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

2009-02-06

We propose an extended version of the standard model, in which neutrino oscillation, dark matter, and the baryon asymmetry of the Universe can be simultaneously explained by the TeV-scale physics without assuming a large hierarchy among the mass scales. Tiny neutrino masses are generated at the three-loop level due to the exact Z2 symmetry, by which the stability of the dark matter candidate is guaranteed. The extra Higgs doublet is required not only for the tiny neutrino masses but also for successful electroweak baryogenesis. The model provides discriminative predictions especially in Higgs phenomenology, so that it is testable at current and future collider experiments.

Short-Term Depression, Temporal Summation, and Onset Inhibition Shape Interval Tuning in Midbrain Neurons

PubMed Central

Baker, Christa A.

2014-01-01

A variety of synaptic mechanisms can contribute to single-neuron selectivity for temporal intervals in sensory stimuli. However, it remains unknown how these mechanisms interact to establish single-neuron sensitivity to temporal patterns of sensory stimulation in vivo. Here we address this question in a circuit that allows us to control the precise temporal patterns of synaptic input to interval-tuned neurons in behaviorally relevant ways. We obtained in vivo intracellular recordings under multiple levels of current clamp from midbrain neurons in the mormyrid weakly electric fish Brienomyrus brachyistius during stimulation with electrosensory pulse trains. To reveal the excitatory and inhibitory inputs onto interval-tuned neurons, we then estimated the synaptic conductances underlying responses. We found short-term depression in excitatory and inhibitory pathways onto all interval-tuned neurons. Short-interval selectivity was associated with excitation that depressed less than inhibition at short intervals, as well as temporally summating excitation. Long-interval selectivity was associated with long-lasting onset inhibition. We investigated tuning after separately nullifying the contributions of temporal summation and depression, and found the greatest diversity of interval selectivity among neurons when both mechanisms were at play. Furthermore, eliminating the effects of depression decreased sensitivity to directional changes in interval. These findings demonstrate that variation in depression and summation of excitation and inhibition helps to establish tuning to behaviorally relevant intervals in communication signals, and that depression contributes to neural coding of interval sequences. This work reveals for the first time how the interplay between short-term plasticity and temporal summation mediates the decoding of temporal sequences in awake, behaving animals. PMID:25339741

Octet baryon masses and sigma terms from an SU(3) chiral extrapolation

NASA Astrophysics Data System (ADS)

Young, R. D.; Thomas, A. W.

2010-01-01

We report an analysis of the impressive new lattice simulation results for octet baryon masses in 2+1-flavor QCD. The analysis is based on a low-order expansion about the chiral SU(3) limit in which the symmetry breaking arises from terms linear in the quark masses plus the variation of the Goldstone boson masses in the leading chiral loops. The baryon masses evaluated at the physical light-quark masses are in remarkable agreement with the experimental values, with a model dependence considerably smaller than the rather small statistical uncertainty. From the mass formulas one can evaluate the sigma commutators for all octet baryons. This yields an accurate value for the pion-nucleon sigma commutator. It also yields the first determination of the strangeness sigma term based on 2+1-flavor lattice QCD and, in general, the sigma commutators provide a resolution to the difficult issue of fine-tuning the strange-quark mass.

Successful N{sub 2} leptogenesis with flavour coupling effects in realistic unified models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bari, Pasquale Di; King, Stephen F.

2015-10-02

In realistic unified models involving so-called SO(10)-inspired patterns of Dirac and heavy right-handed (RH) neutrino masses, the lightest right-handed neutrino N{sub 1} is too light to yield successful thermal leptogenesis, barring highly fine tuned solutions, while the second heaviest right-handed neutrino N{sub 2} is typically in the correct mass range. We show that flavour coupling effects in the Boltzmann equations may be crucial to the success of such N{sub 2} dominated leptogenesis, by helping to ensure that the flavour asymmetries produced at the N{sub 2} scale survive N{sub 1} washout. To illustrate these effects we focus on N{sub 2} dominatedmore » leptogenesis in an existing model, the A to Z of flavour with Pati-Salam, where the neutrino Dirac mass matrix may be equal to an up-type quark mass matrix and has a particular constrained structure. The numerical results, supported by analytical insight, show that in order to achieve successful N{sub 2} leptogenesis, consistent with neutrino phenomenology, requires a “flavour swap scenario” together with a less hierarchical pattern of RH neutrino masses than naively expected, at the expense of some mild fine-tuning. In the considered A to Z model neutrino masses are predicted to be normal ordered, with an atmospheric neutrino mixing angle well into the second octant and the Dirac phase δ≃20{sup ∘}, a set of predictions that will be tested in the next years in neutrino oscillation experiments. Flavour coupling effects may be relevant for other SO(10)-inspired unified models where N{sub 2} leptogenesis is necessary.« less

Successful N{sub 2} leptogenesis with flavour coupling effects in realistic unified models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bari, Pasquale Di; King, Stephen F., E-mail: P.Di-Bari@soton.ac.uk, E-mail: king@soton.ac.uk

2015-10-01

In realistic unified models involving so-called SO(10)-inspired patterns of Dirac and heavy right-handed (RH) neutrino masses, the lightest right-handed neutrino N{sub 1} is too light to yield successful thermal leptogenesis, barring highly fine tuned solutions, while the second heaviest right-handed neutrino N{sub 2} is typically in the correct mass range. We show that flavour coupling effects in the Boltzmann equations may be crucial to the success of such N{sub 2} dominated leptogenesis, by helping to ensure that the flavour asymmetries produced at the N{sub 2} scale survive N{sub 1} washout. To illustrate these effects we focus on N{sub 2} dominatedmore » leptogenesis in an existing model, the A to Z of flavour with Pati-Salam, where the neutrino Dirac mass matrix may be equal to an up-type quark mass matrix and has a particular constrained structure. The numerical results, supported by analytical insight, show that in order to achieve successful N{sub 2} leptogenesis, consistent with neutrino phenomenology, requires a ''flavour swap scenario'' together with a less hierarchical pattern of RH neutrino masses than naively expected, at the expense of some mild fine-tuning. In the considered A to Z model neutrino masses are predicted to be normal ordered, with an atmospheric neutrino mixing angle well into the second octant and the Dirac phase δ≅ 20{sup o}, a set of predictions that will be tested in the next years in neutrino oscillation experiments. Flavour coupling effects may be relevant for other SO(10)-inspired unified models where N{sub 2} leptogenesis is necessary.« less

Contributions of Rod and Cone Pathways to Retinal Direction Selectivity Through Development

PubMed Central

Rosa, Juliana M.; Morrie, Ryan D.; Baertsch, Hans C.

2016-01-01

Direction selectivity is a robust computation across a broad stimulus space that is mediated by activity of both rod and cone photoreceptors through the ON and OFF pathways. However, rods, S-cones, and M-cones activate the ON and OFF circuits via distinct pathways and the relative contribution of each to direction selectivity is unknown. Using a variety of stimulation paradigms, pharmacological agents, and knockout mice that lack rod transduction, we found that inputs from the ON pathway were critical for strong direction-selective (DS) tuning in the OFF pathway. For UV light stimulation, the ON pathway inputs to the OFF pathway originated with rod signaling, whereas for visible stimulation, the ON pathway inputs to the OFF pathway originated with both rod and M-cone signaling. Whole-cell voltage-clamp recordings revealed that blocking the ON pathway reduced directional tuning in the OFF pathway via a reduction in null-side inhibition, which is provided by OFF starburst amacrine cells (SACs). Consistent with this, our recordings from OFF SACs confirmed that signals originating in the ON pathway contribute to their excitation. Finally, we observed that, for UV stimulation, ON contributions to OFF DS tuning matured earlier than direct signaling via the OFF pathway. These data indicate that the retina uses multiple strategies for computing DS responses across different colors and stages of development. SIGNIFICANCE STATEMENT The retina uses parallel pathways to encode different features of the visual scene. In some cases, these distinct pathways converge on circuits that mediate a distinct computation. For example, rod and cone pathways enable direction-selective (DS) ganglion cells to encode motion over a wide range of light intensities. Here, we show that although direction selectivity is robust across light intensities, motion discrimination for OFF signals is dependent upon ON signaling. At eye opening, ON directional tuning is mature, whereas OFF DS tuning is significantly reduced due to a delayed maturation of S-cone to OFF cone bipolar signaling. These results provide evidence that the retina uses multiple strategies for computing DS responses across different stimulus conditions. PMID:27629718

Laser isotope separation by multiple photon absorption

DOEpatents

Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

1987-01-01

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

Laser isotope separation by multiple photon absorption

DOEpatents

Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

1977-01-01

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, in the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

Tuning the thermal conductance of molecular junctions with interference effects

NASA Astrophysics Data System (ADS)

Klöckner, J. C.; Cuevas, J. C.; Pauly, F.

2017-12-01

We present an ab initio study of the role of interference effects in the thermal conductance of single-molecule junctions. To be precise, using a first-principles transport method based on density functional theory, we analyze the coherent phonon transport in single-molecule junctions made of several benzene and oligo(phenylene ethynylene) derivatives. We show that the thermal conductance of these junctions can be tuned via the inclusion of substituents, which induces destructive interference effects and results in a decrease of the thermal conductance with respect to the unmodified molecules. In particular, we demonstrate that these interference effects manifest as antiresonances in the phonon transmission, whose energy positions can be tuned by varying the mass of the substituents. Our work provides clear strategies for the heat management in molecular junctions and, more generally, in nanostructured metal-organic hybrid systems, which are important to determine how these systems can function as efficient energy-conversion devices such as thermoelectric generators and refrigerators.

Advanced Controller Developed for the Free-Piston Stirling Convertor

NASA Technical Reports Server (NTRS)

Gerber, Scott S.

2005-01-01

A free-piston Stirling power convertor is being considered as an advanced power-conversion technology for future NASA deep-space missions requiring long-life radioisotope power systems. The NASA Glenn Research Center has identified key areas where advanced technologies can enhance the capability of Stirling energy-conversion systems. One of these is power electronic controls. Current power-conversion technology for Glenn-tested Stirling systems consists of an engine-driven linear alternator generating an alternating-current voltage controlled by a tuning-capacitor-based alternating-current peak voltage load controller. The tuning capacitor keeps the internal alternator electromotive force (EMF) in phase with its respective current (i.e., passive power factor correction). The alternator EMF is related to the piston velocity, which must be kept in phase with the alternator current in order to achieve stable operation. This tuning capacitor, which adds volume and mass to the overall Stirling convertor, can be eliminated if the controller can actively drive the magnitude and phase of the alternator current.

Heat conduction tuning by hyperbranched nanophononic metamaterials

NASA Astrophysics Data System (ADS)

Li, Bing; Tan, K. T.; Christensen, Johan

2018-05-01

Phonon dispersion and thermal conduction properties of hyperbranched nanostructures with unique topological complexity are theoretically and numerically investigated in this research. We present analytical cantilever-in-mass models to analyze and control the inherent resonance hybridization in hyperbranched nanomembranes containing different configurations and cross sections. We show that these local resonances hosted by hyperbranched nanopillars can generate numerous flat bands in the phonon dispersion relation and dramatically lower the group velocities, consequently resulting in a significant reduction of the thermal conductivity. The applicability of the proposed analytical models in thermal conductivity tuning is demonstrated, and a superior performance in reducing the heat flux in nano-structured membranes is exhibited, which can potentially lead to improved thermoelectric energy conversion devices.

Neural Network-Based Self-Tuning PID Control for Underwater Vehicles

PubMed Central

Hernández-Alvarado, Rodrigo; García-Valdovinos, Luis Govinda; Salgado-Jiménez, Tomás; Gómez-Espinosa, Alfonso; Fonseca-Navarro, Fernando

2016-01-01

For decades, PID (Proportional + Integral + Derivative)-like controllers have been successfully used in academia and industry for many kinds of plants. This is thanks to its simplicity and suitable performance in linear or linearized plants, and under certain conditions, in nonlinear ones. A number of PID controller gains tuning approaches have been proposed in the literature in the last decades; most of them off-line techniques. However, in those cases wherein plants are subject to continuous parametric changes or external disturbances, online gains tuning is a desirable choice. This is the case of modular underwater ROVs (Remotely Operated Vehicles) where parameters (weight, buoyancy, added mass, among others) change according to the tool it is fitted with. In practice, some amount of time is dedicated to tune the PID gains of a ROV. Once the best set of gains has been achieved the ROV is ready to work. However, when the vehicle changes its tool or it is subject to ocean currents, its performance deteriorates since the fixed set of gains is no longer valid for the new conditions. Thus, an online PID gains tuning algorithm should be implemented to overcome this problem. In this paper, an auto-tune PID-like controller based on Neural Networks (NN) is proposed. The NN plays the role of automatically estimating the suitable set of PID gains that achieves stability of the system. The NN adjusts online the controller gains that attain the smaller position tracking error. Simulation results are given considering an underactuated 6 DOF (degrees of freedom) underwater ROV. Real time experiments on an underactuated mini ROV are conducted to show the effectiveness of the proposed scheme. PMID:27608018

Neural Network-Based Self-Tuning PID Control for Underwater Vehicles.

PubMed

Hernández-Alvarado, Rodrigo; García-Valdovinos, Luis Govinda; Salgado-Jiménez, Tomás; Gómez-Espinosa, Alfonso; Fonseca-Navarro, Fernando

2016-09-05

For decades, PID (Proportional + Integral + Derivative)-like controllers have been successfully used in academia and industry for many kinds of plants. This is thanks to its simplicity and suitable performance in linear or linearized plants, and under certain conditions, in nonlinear ones. A number of PID controller gains tuning approaches have been proposed in the literature in the last decades; most of them off-line techniques. However, in those cases wherein plants are subject to continuous parametric changes or external disturbances, online gains tuning is a desirable choice. This is the case of modular underwater ROVs (Remotely Operated Vehicles) where parameters (weight, buoyancy, added mass, among others) change according to the tool it is fitted with. In practice, some amount of time is dedicated to tune the PID gains of a ROV. Once the best set of gains has been achieved the ROV is ready to work. However, when the vehicle changes its tool or it is subject to ocean currents, its performance deteriorates since the fixed set of gains is no longer valid for the new conditions. Thus, an online PID gains tuning algorithm should be implemented to overcome this problem. In this paper, an auto-tune PID-like controller based on Neural Networks (NN) is proposed. The NN plays the role of automatically estimating the suitable set of PID gains that achieves stability of the system. The NN adjusts online the controller gains that attain the smaller position tracking error. Simulation results are given considering an underactuated 6 DOF (degrees of freedom) underwater ROV. Real time experiments on an underactuated mini ROV are conducted to show the effectiveness of the proposed scheme.

Experimental investigation of dynamic performance of a prototype hybrid tuned mass damper under human excitation

NASA Astrophysics Data System (ADS)

Noormohammadi, Nima; Reynolds, Paul

2013-04-01

Current sport stadia designs focus mainly on maximizing audience capacity and providing a clear view for all spectators. Hence, incorporation of one or more cantilevered tiers is typical in these designs. However, employing such cantilevered tiers, usually with relatively low damping and natural frequencies, can make grandstands more susceptible to excitation by human activities. This is caused by the coincidence between the activity frequencies (and their lowest three harmonics) and the structural natural frequencies hence raising the possibility of resonant vibration. This can be both a vibration serviceability and a safety issue. Past solutions to deal with observed or anticipated vibration serviceability problems have been mainly passive methods, such as tuned mass dampers (TMDs). These techniques have exhibited problems such as lack of performance and offtuning caused by human-structure interaction. To address this issue, research is currently underway to investigate the possible application of hybrid TMDs (HTMDs), which are a combination of active and passive control, to improve the vibration serviceability of such structures under human excitation. The work presented here shows a comparative experimental investigation of a passive TMD and a prototype HTMD applied on a slab strip structure. The most effective control algorithm to enhance the performance of the HTMD and also deal with the off-tuning problem is investigated. The laboratory structure used here is an in-situ cast simply-supported post-tensioned slab strip excited by forces from a range of human activities.

Acoustic metamaterial plate embedded with Helmholtz resonators for extraordinary sound transmission loss

NASA Astrophysics Data System (ADS)

Yamamoto, Takashi

2018-06-01

A new acoustic metamaterial plate (AMP) is proposed herein. The plate incorporates Helmholtz resonators that are periodically embedded at intervals shorter than acoustic wavelengths. This metamaterial plate exhibits extraordinary sound transmission loss (STL) at the resonance frequency of the Helmholtz resonators compared to a conventional flat plate. The STL of the AMP can be theoretically analyzed using the effective mass density and flexural rigidity. At the resonant frequency, the dynamic density of the AMP becomes much larger than that of a conventional solid flat plate with the same mass. When the Helmholtz resonant frequency is tuned to the coincidence frequency of the AMP, the dip in transmission loss owing to the coincidence effect is not observed. The frequency band, wherein high STL occurs, is narrow; however, the frequency band can be widened by embedding multiple resonators with slightly different resonant frequencies. Numerical experiments are also performed to demonstrate the acoustic performance of the proposed system. In the simulation, Helmholtz resonators with the 2.1-kHz resonant frequency are embedded at 20-mm intervals inside a 6-mm-thick flat glass plate. Analytical solutions of this system agree well with numerical solutions for various incidence angles of incoming plane waves. In this configuration, we find that the degradation of STL caused by the coincidence effect is nearly eliminated for waves that are incident at random angles.

Extracting muon momentum scale corrections for hadron collider experiments

NASA Astrophysics Data System (ADS)

Bodek, A.; van Dyne, A.; Han, J. Y.; Sakumoto, W.; Strelnikov, A.

2012-10-01

We present a simple method for the extraction of corrections for bias in the measurement of the momentum of muons in hadron collider experiments. Such bias can originate from a variety of sources such as detector misalignment, software reconstruction bias, and uncertainties in the magnetic field. The two step method uses the mean <1/p^{μ}T rangle for muons from Z→ μμ decays to determine the momentum scale corrections in bins of charge, η and ϕ. In the second step, the corrections are tuned by using the average invariant mass < MZ_{μμ }rangle of Z→ μμ events in the same bins of charge η and ϕ. The forward-backward asymmetry of Z/ γ ∗→ μμ pairs as a function of μ + μ - mass, and the ϕ distribution of Z bosons in the Collins-Soper frame are used to ascertain that the corrections remove the bias in the momentum measurements for positive versus negatively charged muons. By taking the sum and difference of the momentum scale corrections for positive and negative muons, we isolate additive corrections to 1/p^{μ}T that may originate from misalignments and multiplicative corrections that may originate from mis-modeling of the magnetic field (∫ Bṡ d L). This method has recently been used in the CDF experiment at Fermilab and in the CMS experiment at the Large Hadron Collider at CERN.

Breadth of tuning in taste afferent neurons varies with stimulus strength

PubMed Central

Wu, An; Dvoryanchikov, Gennady; Pereira, Elizabeth; Chaudhari, Nirupa; Roper, Stephen D.

2015-01-01

Gustatory stimuli are detected by taste buds and transmitted to the hindbrain via sensory afferent neurons. Whether each taste quality (sweet, bitter and so on) is encoded by separate neurons (‘labelled lines') remains controversial. We used mice expressing GCaMP3 in geniculate ganglion sensory neurons to investigate taste-evoked activity. Using confocal calcium imaging, we recorded responses to oral stimulation with prototypic taste stimuli. Up to 69% of neurons respond to multiple tastants. Moreover, neurons tuned to a single taste quality at low concentration become more broadly tuned when stimuli are presented at higher concentration. Responses to sucrose and monosodium glutamate are most related. Although mice prefer dilute NaCl solutions and avoid concentrated NaCl, we found no evidence for two separate populations of sensory neurons that encode this distinction. Altogether, our data suggest that taste is encoded by activity in patterns of peripheral sensory neurons and challenge the notion of strict labelled line coding. PMID:26373451

Attention-related changes in correlated neuronal activity arise from normalization mechanisms

PubMed Central

Verhoef, Bram-Ernst; Maunsell, John H.R.

2017-01-01

Attention is believed to enhance perception by altering the correlations between pairs of neurons. How attention changes neuronal correlations is unknown. Using multi-electrodes in primate visual cortex, we measured spike-count correlations when single or multiple stimuli were presented, and stimuli were attended or unattended. When stimuli were unattended, adding a suppressive, non-preferred, stimulus beside a preferred stimulus increased spike-count correlations between pairs of similarly-tuned neurons, but decreased spike-count correlations between pairs of oppositely-tuned neurons. These changes are explained by a stochastic normalization model containing populations of oppositely-tuned, mutually-suppressive neurons. Importantly, this model also explains why attention decreased (attend preferred stimulus) or increased (attend non-preferred stimulus) correlations: as an indirect consequence of attention-related changes in the inputs to normalization mechanisms. Our findings link normalization mechanisms to correlated neuronal activity and attention, showing that normalization mechanisms shape response correlations and that these correlations change when attention biases normalization mechanisms. PMID:28553943

Simulated electron affinity tuning in metal-insulator-metal (MIM) diodes

NASA Astrophysics Data System (ADS)

Mistry, Kissan; Yavuz, Mustafa; Musselman, Kevin P.

2017-05-01

Metal-insulator-metal diodes for rectification applications must exhibit high asymmetry, nonlinearity, and responsivity. Traditional methods of improving these figures of merit have consisted of increasing insulator thickness, adding multiple insulator layers, and utilizing a variety of metal contact combinations. However, these methods have come with the price of increasing the diode resistance and ultimately limiting the operating frequency to well below the terahertz regime. In this work, an Airy Function Transfer Matrix simulation method was used to observe the effect of tuning the electron affinity of the insulator as a technique to decrease the diode resistance. It was shown that a small increase in electron affinity can result in a resistance decrease in upwards of five orders of magnitude, corresponding to an increase in operating frequency on the same order. Electron affinity tuning has a minimal effect on the diode figures of merit, where asymmetry improves or remains unaffected and slight decreases in nonlinearity and responsivity are likely to be greatly outweighed by the improved operating frequency of the diode.

In Situ Generation of Plasmonic Nanoparticles for Manipulating Photon-Plasmon Coupling in Microtube Cavities.

PubMed

Yin, Yin; Wang, Jiawei; Lu, Xueyi; Hao, Qi; Saei Ghareh Naz, Ehsan; Cheng, Chuanfu; Ma, Libo; Schmidt, Oliver G

2018-04-24

In situ generation of silver nanoparticles for selective coupling between localized plasmonic resonances and whispering-gallery modes (WGMs) is investigated by spatially resolved laser dewetting on microtube cavities. The size and morphology of the silver nanoparticles are changed by adjusting the laser power and irradiation time, which in turn effectively tune the photon-plasmon coupling strength. Depending on the relative position of the plasmonic nanoparticles spot and resonant field distribution of WGMs, selective coupling between the localized surface plasmon resonances (LSPRs) and WGMs is experimentally demonstrated. Moreover, by creating multiple plasmonic-nanoparticle spots on the microtube cavity, the field distribution of optical axial modes is freely tuned due to multicoupling between LSPRs and WGMs. The multicoupling mechanism is theoretically investigated by a modified quasipotential model based on perturbation theory. This work provides an in situ fabrication of plasmonic nanoparticles on three-dimensional microtube cavities for manipulating photon-plasmon coupling which is of interest for optical tuning abilities and enhanced light-matter interactions.

Nonlinear parity readout with a microwave photodetector

NASA Astrophysics Data System (ADS)

Schöndorf, M.; Wilhelm, F. K.

2018-04-01

Robust high-fidelity parity measurement is an important operation in many applications of quantum computing. In this work we show how in a circuit QED architecture, one can measure parity in a single shot at very high contrast by taking advantage of the nonlinear behavior of a strongly driven microwave cavity coupled to one or multiple qubits. We work in a nonlinear dispersive regime treated in an exact dispersive transformation. We show that appropriate tuning of experimental parameters leads to very high contrast in the cavity and therefore to a high-efficiency parity readout with a microwave photon counter or another amplitude detector. These tuning conditions are based on nonlinearity and are hence more robust than previously described linear tuning schemes. In the first part of the paper we show in detail how to achieve this for two-qubit parity measurements and extend this to N qubits in the second part of the paper. We also study the quantum nondemolition character of the protocol.

Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds.

PubMed

Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedl, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

2016-07-12

Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination.

Who We Are: Today's Students Speak Out

ERIC Educational Resources Information Center

Blandford, Ayoka

2012-01-01

Today's students have been nicknamed the "Digital Generation," "Millennials," "Net Generation" and "Generation Next." They are frequently identified by their technological prowess and seem to work well with multiple stimuli (for example, designing a web site while listening to iTunes and responding to texts). While many research studies have been…

Multiple Learning Strategies Project. Small Engine Repair. Visually Impaired.

ERIC Educational Resources Information Center

Foster, Don; And Others

This instructional package designed for visually impaired students, focuses on the vocational area of small engine repair. Contained in this document are forty learning modules organized into fourteen units: engine block; starters; fuel tank, lines, filters and pumps; carburetors; electrical; test equipment; motorcycle; machining; tune-ups; short…

The qualitative assessment of pneumatic actuators operation in terms of vibration criteria

NASA Astrophysics Data System (ADS)

Hetmanczyk, M. P.; Michalski, P.

2015-11-01

The work quality of pneumatic actuators can be assessed in terms of multiple criteria. In the case of complex systems with pneumatic actuators retained at end positions (with occurrence of piston impact in cylinder covers) the vibration criteria constitute the most reliable indicators. The paper presents an impact assessment on the operating condition of the rodless pneumatic cylinder regarding to selected vibrational symptoms. On the basis of performed analysis the authors had shown meaningful premises allowing an evaluation of the performance and tuning of end position damping piston movement with usage the most common diagnostic tools (portable vibration analyzers). The presented method is useful in tuning of parameters in industrial conditions.

Fine tuning of the dichroic behavior of Bragg reflectors based on anisotropically nanostructured silicon

NASA Astrophysics Data System (ADS)

Diener, J.; Künzner, N.; Kovalev, D.; Gross, E.; Koch, F.; Fujii, M.

2003-05-01

Electro-chemical etching of heavily doped, (110) oriented, p+ (boron) doped silicon wafers results in porous silicon (PSi) layers which exhibit a strong in-plane anisotropy of the refractive index (birefringence). Single- and multiple layers of anisotropically nanostructured silicon (Si) have been fabricated and studied by polarization-resolved reflection and transmission measurements. Dielectric stacks of birefringent PSi acting as distributed Bragg reflectors have two distinct reflection bands depending on the polarization of the incident linearly polarized light. This effect is caused by a three-dimensional (in plane and in-depth) variation of the refraction index. The possibility of fine tuning the two orthogonally polarized reflection bands and their spectral splitting is demonstrated.

Demonstration of a rapidly-swept external cavity quantum cascade laser for rapid and sensitive quantification of chemical mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brumfield, Brian E.; Taubman, Matthew S.; Phillips, Mark C.

2016-02-13

A rapidly-swept external cavity quantum cascade laser (ECQCL) system for fast open-path quantification of multiple chemicals and mixtures is presented. The ECQCL system is swept over its entire tuning range (>100 cm-1) at frequencies up to 200 Hz. At 200 Hz the wavelength tuning rate and spectral resolution are 2x104 cm-1/sec and < 0.2 cm-1, respectively. The capability of the current system to quantify changes in chemical concentrations on millesecond timescales is demonstrated at atmospheric pressure using an open-path multi-pass cell. The detection limits for chemicals ranged from ppb to ppm levels depending on the absorption cross-section.

Method development aspects for the quantitation of pharmaceutical compounds in human plasma with a matrix-assisted laser desorption/ionization source in the multiple reaction monitoring mode.

PubMed

Kovarik, Peter; Grivet, Chantal; Bourgogne, Emmanuel; Hopfgartner, Gérard

2007-01-01

The present work investigates various method development aspects for the quantitative analysis of pharmaceutical compounds in human plasma using matrix-assisted laser desorption/ionization and multiple reaction monitoring (MALDI-MRM). Talinolol was selected as a model analyte. Liquid-liquid extraction (LLE) and protein precipitation were evaluated regarding sensitivity and throughput for the MALDI-MRM technique and its applicability without and with chromatographic separation. Compared to classical electrospray liquid chromatography/mass spectrometry (LC/ESI-MS) method development, with MALDI-MRM the tuning of the analyte in single MS mode is more challenging due to interfering matrix background ions. An approach is proposed using background subtraction. With LLE and using a 200 microL human plasma aliquot acceptable precision and accuracy could be obtained in the range of 1 to 1000 ng/mL without any LC separation. Approximately 3 s were required for one analysis. A full calibration curve and its quality control samples (20 samples) can be analyzed within 1 min. Combining LC with the MALDI analysis allowed improving the linearity down to 50 pg/mL, while reducing the throughput potential only by two-fold. Matrix effects are still a significant issue with MALDI but can be monitored in a similar way to that used for LC/ESI-MS analysis.

Development of a MEMS device for acoustic emission testing

NASA Astrophysics Data System (ADS)

Ozevin, Didem; Pessiki, Stephen P.; Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2003-08-01

Acoustic emission testing is an important technology for evaluating structural materials, and especially for detecting damage in structural members. Significant new capabilities may be gained by developing MEMS transducers for acoustic emission testing, including permanent bonding or embedment for superior coupling, greater density of transducer placement, and a bundle of transducers on each device tuned to different frequencies. Additional advantages include capabilities for maintenance of signal histories and coordination between multiple transducers. We designed a MEMS device for acoustic emission testing that features two different mechanical types, a hexagonal plate design and a spring-mass design, with multiple detectors of each type at ten different frequencies in the range of 100 kHz to 1 MHz. The devices were fabricated in the multi-user polysilicon surface micromachining (MUMPs) process and we have conducted electrical characterization experiments and initial experiments on acoustic emission detection. We first report on C(V) measurements and perform a comparison between predicted (design) and measured response. We next report on admittance measurements conducted at pressures varying from vacuum to atmospheric, identifying the resonant frequencies and again providing a comparison with predicted performance. We then describe initial calibration experiments that compare the performance of the detectors to other acoustic emission transducers, and we discuss the overall performance of the device as a sensor suite, as contrasted to the single-channel performance of most commercial transducers.

Deficient GABAergic gliotransmission may cause broader sensory tuning in schizophrenia.

PubMed

Hoshino, Osamu

2013-12-01

We examined how the depression of intracortical inhibition due to a reduction in ambient GABA concentration impairs perceptual information processing in schizophrenia. A neural network model with a gliotransmission-mediated ambient GABA regulatory mechanism was simulated. In the network, interneuron-to-glial-cell and principal-cell-to-glial-cell synaptic contacts were made. The former hyperpolarized glial cells and let their transporters import (remove) GABA from the extracellular space, thereby lowering ambient GABA concentration, reducing extrasynaptic GABAa receptor-mediated tonic inhibitory current, and thus exciting principal cells. In contrast, the latter depolarized the glial cells and let the transporters export GABA into the extracellular space, thereby elevating the ambient GABA concentration and thus inhibiting the principal cells. A reduction in ambient GABA concentration was assumed for a schizophrenia network. Multiple dynamic cell assemblies were organized as sensory feature columns. Each cell assembly responded to one specific feature stimulus. The tuning performance of the network to an applied feature stimulus was evaluated in relation to the level of ambient GABA. Transporter-deficient glial cells caused a deficit in GABAergic gliotransmission and reduced ambient GABA concentration, which markedly deteriorated the tuning performance of the network, broadening the sensory tuning. Interestingly, the GABAergic gliotransmission mechanism could regulate local ambient GABA levels: it augmented ambient GABA around stimulus-irrelevant principal cells, while reducing ambient GABA around stimulus-relevant principal cells, thereby ensuring their selective responsiveness to the applied stimulus. We suggest that a deficit in GABAergic gliotransmission may cause a reduction in ambient GABA concentration, leading to a broadening of sensory tuning in schizophrenia. The GABAergic gliotransmission mechanism proposed here may have an important role in the regulation of local ambient GABA levels, thereby improving the sensory tuning performance of the cortex.

Moving in Time to a Digital Tune: A Crisis in Our Identity?

ERIC Educational Resources Information Center

Mc Taggart, Breda

2015-01-01

The higher educational landscape nationally and internationally has changed over the last decades, moving from an elite to a mass higher educational system (Trow,1984). Currently this system and the organisations within it are contending with new external influences on their future structure--the arrival of the technological revolution and…

The Möbius domain wall fermion algorithm

NASA Astrophysics Data System (ADS)

Brower, Richard C.; Neff, Harmut; Orginos, Kostas

2017-11-01

We present a review of the properties of generalized domain wall Fermions, based on a (real) Möbius transformation on the Wilson overlap kernel, discussing their algorithmic efficiency, the degree of explicit chiral violations measured by the residual mass (mres) and the Ward-Takahashi identities. The Möbius class interpolates between Shamir's domain wall operator and Boriçi's domain wall implementation of Neuberger's overlap operator without increasing the number of Dirac applications per conjugate gradient iteration. A new scaling parameter (α) reduces chiral violations at finite fifth dimension (Ls) but yields exactly the same overlap action in the limit Ls → ∞. Through the use of 4d Red/Black preconditioning and optimal tuning for the scaling α(Ls) , we show that chiral symmetry violations are typically reduced by an order of magnitude at fixed Ls. We argue that the residual mass for a tuned Möbius algorithm with α = O(1 /Lsγ) for γ < 1 will eventually fall asymptotically as mres = O(1 /Ls1+γ) in the case of a 5D Hamiltonian with out a spectral gap.

Tuned mass damper for integrally bladed turbine rotor

NASA Technical Reports Server (NTRS)

Marra, John J. (Inventor)

1994-01-01

The invention is directed to a damper ring for damping the natural vibration of the rotor blades of an integrally bladed rocket turbine rotor. The invention consists of an integral damper ring which is fixed to the underside of the rotor blade platform of a turbine rotor. The damper ring includes integral supports which extend radially outwardly therefrom. The supports are located adjacent to the base portion and directly under each blade of the rotor. Vibration damping is accomplished by action of tuned mass damper beams attached at each end to the supports. These beams vibrate at a predetermined frequency during operation. The vibration of the beams enforce a local node of zero vibratory amplitude at the interface between the supports and the beam. The vibration of the beams create forces upon the supports which forces are transmitted through the rotor blade mounting platform to the base of each rotor blade. When these forces attain a predetermined design frequency and magnitude and are directed to the base of the rotor blades, vibration of the rotor blades is effectively counteracted.

Summary of the ATLAS experiment’s sensitivity to supersymmetry after LHC Run 1 -- interpreted in the phenomenological MSSM

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2015-10-21

A summary of the constraints from the ATLAS experiment on R -parity-conserving supersymmetry is presented. Results from 22 separate ATLAS searches are considered, each based on analysis of up to 20.3 fb –1 of proton-proton collision data at centre-of-mass energies of √s =7 and 8 TeV at the Large Hadron Collider. The results are interpreted in the context of the 19-parameter phenomenological minimal supersymmetric standard model, in which the lightest supersymmetric particle is a neutralino, taking into account constraints from previous precision electroweak and flavour measurements as well as from dark matter related measurements. The results are presented in termsmore » of constraints on supersymmetric particle masses and are compared to limits from simplified models. The impact of ATLAS searches on parameters such as the dark matter relic density, the couplings of the observed Higgs boson, and the degree of electroweak fine-tuning is also shown. As a result, spectra for surviving supersymmetry model points with low fine-tunings are presented.« less

Neuromechanical tuning of nonlinear postural control dynamics

NASA Astrophysics Data System (ADS)

Ting, Lena H.; van Antwerp, Keith W.; Scrivens, Jevin E.; McKay, J. Lucas; Welch, Torrence D. J.; Bingham, Jeffrey T.; DeWeerth, Stephen P.

2009-06-01

Postural control may be an ideal physiological motor task for elucidating general questions about the organization, diversity, flexibility, and variability of biological motor behaviors using nonlinear dynamical analysis techniques. Rather than presenting "problems" to the nervous system, the redundancy of biological systems and variability in their behaviors may actually be exploited to allow for the flexible achievement of multiple and concurrent task-level goals associated with movement. Such variability may reflect the constant "tuning" of neuromechanical elements and their interactions for movement control. The problem faced by researchers is that there is no one-to-one mapping between the task goal and the coordination of the underlying elements. We review recent and ongoing research in postural control with the goal of identifying common mechanisms underlying variability in postural control, coordination of multiple postural strategies, and transitions between them. We present a delayed-feedback model used to characterize the variability observed in muscle coordination patterns during postural responses to perturbation. We emphasize the significance of delays in physiological postural systems, requiring the modulation and coordination of both the instantaneous, "passive" response to perturbations as well as the delayed, "active" responses to perturbations. The challenge for future research lies in understanding the mechanisms and principles underlying neuromechanical tuning of and transitions between the diversity of postural behaviors. Here we describe some of our recent and ongoing studies aimed at understanding variability in postural control using physical robotic systems, human experiments, dimensional analysis, and computational models that could be enhanced from a nonlinear dynamics approach.

Second-order sliding mode controller with model reference adaptation for automatic train operation

NASA Astrophysics Data System (ADS)

Ganesan, M.; Ezhilarasi, D.; Benni, Jijo

2017-11-01

In this paper, a new approach to model reference based adaptive second-order sliding mode control together with adaptive state feedback is presented to control the longitudinal dynamic motion of a high speed train for automatic train operation with the objective of minimal jerk travel by the passengers. The nonlinear dynamic model for the longitudinal motion of the train comprises of a locomotive and coach subsystems is constructed using multiple point-mass model by considering the forces acting on the vehicle. An adaptation scheme using Lyapunov criterion is derived to tune the controller gains by considering a linear, stable reference model that ensures the stability of the system in closed loop. The effectiveness of the controller tracking performance is tested under uncertain passenger load, coupler-draft gear parameters, propulsion resistance coefficients variations and environmental disturbances due to side wind and wet rail conditions. The results demonstrate improved tracking performance of the proposed control scheme with a least jerk under maximum parameter uncertainties when compared to constant gain second-order sliding mode control.

Broken flavor 2↔3 symmetry and phenomenological approach for universal quark and lepton mass matrices

NASA Astrophysics Data System (ADS)

Matsuda, Koichi; Nishiura, Hiroyuki

2006-01-01

A phenomenological approach for the universal mass matrix model with a broken flavor 2↔3 symmetry is explored by introducing the 2↔3 antisymmetric parts of mass matrices for quarks and charged leptons. We present explicit texture components of the mass matrices, which are consistent with all the neutrino oscillation experiments and quark mixing data. The mass matrices have a common structure for quarks and leptons, while the large lepton mixings and the small quark mixings are derived with no fine-tuning due to the difference of the phase factors. The model predicts a value 2.4×10-3 for the lepton mixing matrix element square |U13|2, and also ⟨mν⟩=(0.89-1.4)×10-4eV for the averaged neutrino mass which appears in the neutrinoless double beta decay.

Hollow-Structured Graphene-Silicone-Composite-Based Piezoresistive Sensors: Decoupled Property Tuning and Bending Reliability.

PubMed

Luo, Ningqi; Huang, Yan; Liu, Jing; Chen, Shih-Chi; Wong, Ching Ping; Zhao, Ni

2017-10-01

A versatile flexible piezoresistive sensor should maintain high sensitivity in a wide linear range, and provide a stable and repeatable pressure reading under bending. These properties are often difficult to achieve simultaneously with conventional filler-matrix composite active materials, as tuning of one material component often results in change of multiple sensor properties. Here, a material strategy is developed to realize a 3D graphene-poly(dimethylsiloxane) hollow structure, where the electrical conductivity and mechanical elasticity of the composite can be tuned separately by varying the graphene layer number and the poly(dimethylsiloxane) composition ratio, respectively. As a result, the sensor sensitivity and linear range can be easily improved through a decoupled tuning process, reaching a sensitivity of 15.9 kPa -1 in a 60 kPa linear region, and the sensor also exhibits fast response (1.2 ms rising time) and high stability. Furthermore, by optimizing the density of the graphene percolation network and thickness of the composite, the stability and repeatability of the sensor output under bending are improved, achieving a measurement error below 6% under bending radius variations from -25 to +25 mm. Finally, the potential applications of these sensors in wearable medical devices and robotic vision are explored. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unscented Kalman Filter for Brain-Machine Interfaces

PubMed Central

Li, Zheng; O'Doherty, Joseph E.; Hanson, Timothy L.; Lebedev, Mikhail A.; Henriquez, Craig S.; Nicolelis, Miguel A. L.

2009-01-01

Brain machine interfaces (BMIs) are devices that convert neural signals into commands to directly control artificial actuators, such as limb prostheses. Previous real-time methods applied to decoding behavioral commands from the activity of populations of neurons have generally relied upon linear models of neural tuning and were limited in the way they used the abundant statistical information contained in the movement profiles of motor tasks. Here, we propose an n-th order unscented Kalman filter which implements two key features: (1) use of a non-linear (quadratic) model of neural tuning which describes neural activity significantly better than commonly-used linear tuning models, and (2) augmentation of the movement state variables with a history of n-1 recent states, which improves prediction of the desired command even before incorporating neural activity information and allows the tuning model to capture relationships between neural activity and movement at multiple time offsets simultaneously. This new filter was tested in BMI experiments in which rhesus monkeys used their cortical activity, recorded through chronically implanted multielectrode arrays, to directly control computer cursors. The 10th order unscented Kalman filter outperformed the standard Kalman filter and the Wiener filter in both off-line reconstruction of movement trajectories and real-time, closed-loop BMI operation. PMID:19603074

Deep Convolutional Neural Networks for breast cancer screening.

PubMed

Chougrad, Hiba; Zouaki, Hamid; Alheyane, Omar

2018-04-01

Radiologists often have a hard time classifying mammography mass lesions which leads to unnecessary breast biopsies to remove suspicions and this ends up adding exorbitant expenses to an already burdened patient and health care system. In this paper we developed a Computer-aided Diagnosis (CAD) system based on deep Convolutional Neural Networks (CNN) that aims to help the radiologist classify mammography mass lesions. Deep learning usually requires large datasets to train networks of a certain depth from scratch. Transfer learning is an effective method to deal with relatively small datasets as in the case of medical images, although it can be tricky as we can easily start overfitting. In this work, we explore the importance of transfer learning and we experimentally determine the best fine-tuning strategy to adopt when training a CNN model. We were able to successfully fine-tune some of the recent, most powerful CNNs and achieved better results compared to other state-of-the-art methods which classified the same public datasets. For instance we achieved 97.35% accuracy and 0.98 AUC on the DDSM database, 95.50% accuracy and 0.97 AUC on the INbreast database and 96.67% accuracy and 0.96 AUC on the BCDR database. Furthermore, after pre-processing and normalizing all the extracted Regions of Interest (ROIs) from the full mammograms, we merged all the datasets to build one large set of images and used it to fine-tune our CNNs. The CNN model which achieved the best results, a 98.94% accuracy, was used as a baseline to build the Breast Cancer Screening Framework. To evaluate the proposed CAD system and its efficiency to classify new images, we tested it on an independent database (MIAS) and got 98.23% accuracy and 0.99 AUC. The results obtained demonstrate that the proposed framework is performant and can indeed be used to predict if the mass lesions are benign or malignant. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous fast measurement of circuit dynamics at multiple sites across the mammalian brain

PubMed Central

Kim, Christina K; Yang, Samuel J; Pichamoorthy, Nandini; Young, Noah P; Kauvar, Isaac; Jennings, Joshua H; Lerner, Talia N; Berndt, Andre; Lee, Soo Yeun; Ramakrishnan, Charu; Davidson, Thomas J; Inoue, Masatoshi; Bito, Haruhiko; Deisseroth, Karl

2017-01-01

Real-time activity measurements from multiple specific cell populations and projections are likely to be important for understanding the brain as a dynamical system. Here we developed frame-projected independent-fiber photometry (FIP), which we used to record fluorescence activity signals from many brain regions simultaneously in freely behaving mice. We explored the versatility of the FIP microscope by quantifying real-time activity relationships among many brain regions during social behavior, simultaneously recording activity along multiple axonal pathways during sensory experience, performing simultaneous two-color activity recording, and applying optical perturbation tuned to elicit dynamics that match naturally occurring patterns observed during behavior. PMID:26878381

Laser isotope separation by multiple photon absorption

DOEpatents

Robinson, C.P.; Rockwood, S.D.; Jensen, R.J.; Lyman, J.L.; Aldridge, J.P. III.

1987-04-07

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO[sub 2] laser light may be used to highly enrich [sup 34]S in natural SF[sub 6] and [sup 11]B in natural BCl[sub 3]. 8 figs.

Optimization under uncertainty of parallel nonlinear energy sinks

NASA Astrophysics Data System (ADS)

Boroson, Ethan; Missoum, Samy; Mattei, Pierre-Olivier; Vergez, Christophe

2017-04-01

Nonlinear Energy Sinks (NESs) are a promising technique for passively reducing the amplitude of vibrations. Through nonlinear stiffness properties, a NES is able to passively and irreversibly absorb energy. Unlike the traditional Tuned Mass Damper (TMD), NESs do not require a specific tuning and absorb energy over a wider range of frequencies. Nevertheless, they are still only efficient over a limited range of excitations. In order to mitigate this limitation and maximize the efficiency range, this work investigates the optimization of multiple NESs configured in parallel. It is well known that the efficiency of a NES is extremely sensitive to small perturbations in loading conditions or design parameters. In fact, the efficiency of a NES has been shown to be nearly discontinuous in the neighborhood of its activation threshold. For this reason, uncertainties must be taken into account in the design optimization of NESs. In addition, the discontinuities require a specific treatment during the optimization process. In this work, the objective of the optimization is to maximize the expected value of the efficiency of NESs in parallel. The optimization algorithm is able to tackle design variables with uncertainty (e.g., nonlinear stiffness coefficients) as well as aleatory variables such as the initial velocity of the main system. The optimal design of several parallel NES configurations for maximum mean efficiency is investigated. Specifically, NES nonlinear stiffness properties, considered random design variables, are optimized for cases with 1, 2, 3, 4, 5, and 10 NESs in parallel. The distributions of efficiency for the optimal parallel configurations are compared to distributions of efficiencies of non-optimized NESs. It is observed that the optimization enables a sharp increase in the mean value of efficiency while reducing the corresponding variance, thus leading to more robust NES designs.

Learned suppression for multiple distractors in visual search.

PubMed

Won, Bo-Yeong; Geng, Joy J

2018-05-07

Visual search for a target object occurs rapidly if there were no distractors to compete for attention, but this rarely happens in real-world environments. Distractors are almost always present and must be suppressed for target selection to succeed. Previous research suggests that one way this occurs is through the creation of a stimulus-specific distractor template. However, it remains unknown how information within such templates scale up with multiple distractors. Here we investigated the informational content of distractor templates created from repeated exposures to multiple distractors. We investigated this question using a visual search task in which participants searched for a gray square among colored squares. During "training," participants always saw the same set of colored distractors. During "testing," new distractor sets were interleaved with the trained distractors. The critical manipulation in each study was the distance (in color space) of the new test distractors from the trained distractors. We hypothesized that the pattern of distractor interference during testing would reveal the tuning of the suppression template: RTs should be commensurate with the degree to which distractor colors are encoded within the suppression template. Results from four experiments converged on the notion that the distractor template includes information about specific color values, but has broad "tuning," allowing suppression to generalize to new distractors. These results suggest that distractor templates, unlike target templates, encode multiple features and have broad representations, which have the advantage of generalizing suppression more easily to other potential distractors. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Hybrid Active-Passive Systems for Control of Aircraft Interior Noise

NASA Technical Reports Server (NTRS)

Fuller, Chris R.

1999-01-01

Previous work has demonstrated the large potential for hybrid active-passive systems for attenuating interior noise in aircraft fuselages. The main advantage of an active-passive system is, by utilizing the natural dynamics of the actuator system, the control actuator power and weight is markedly reduced and stability/robustness is enhanced. Three different active-passive approaches were studied in the past year. The first technique utilizes multiple tunable vibration absorbers (ATVA) for reducing narrow band sound radiated from panels and transmitted through fuselage structures. The focus is on reducing interior noise due to propeller or turbo fan harmonic excitation. Two types of tunable vibration absorbers were investigated; a solid state system based upon a piezoelectric mechanical exciter and an electromechanical system based upon a Motran shaker. Both of these systems utilize a mass-spring dynamic effect to maximize tile output force near resonance of the shaker system and so can also be used as vibration absorbers. The dynamic properties of the absorbers (i.e. resonance frequency) were modified using a feedback signal from an accelerometer mounted on the active mass, passed through a compensator and fed into the drive component of the shaker system (piezoelectric element or voice coil respectively). The feedback loop consisted of a two coefficient FIR filter, implemented on a DSP, where the input is acceleration of tile ATVA mass and the output is a force acting in parallel with the stiffness of the absorber. By separating the feedback signal into real and imaginary components, the effective natural frequency and damping of the ATVA can be altered independently. This approach gave control of the resonance frequencies while also allowing the simultaneous removal of damping from the ATVA, thus increasing the ease of controllability and effectiveness. In order to obtain a "tuned" vibration absorber the chosen resonant frequency was set to the excitation frequency. In order to minimize sound radiation a gradient descent algorithm was developed which globally adapted the resonance frequencies of multiple ATVA's while minimizing a cost based upon the radiated sound power or sound energy obtained from an array of microphones.

Analysis of the right-handed Majorana neutrino mass in an S U (4 )×S U (2 )L×S U (2 )R Pati-Salam model with democratic texture

NASA Astrophysics Data System (ADS)

Yang, Masaki J. S.

2017-03-01

In this paper, we attempt to build a unified model with the democratic texture, that has some unification between up-type Yukawa interactions Yν and Yu . Since the S3 L×S3 R flavor symmetry is chiral, the unified gauge group is assumed to be Pati-Salam type S U (4 )c×S U (2 )L×S U (2 )R. The breaking scheme of the flavor symmetry is considered to be S3 L×S3 R→S2 L×S2 R→0 . In this picture, the four-zero texture is desirable for realistic masses and mixings. This texture is realized by a specific representation for the second breaking of the S3 L×S3 R flavor symmetry. Assuming only renormalizable Yukawa interactions, type-I seesaw mechanism, and neglecting C P phases for simplicity, the right-handed neutrino mass matrix MR can be reconstructed from low energy input values. Numerical analysis shows that the texture of MR basically behaves like the "waterfall texture." Since MR tends to be the "cascade texture" in the democratic texture approach, a model with type-I seesaw and up-type Yukawa unification Yν≃Yu basically requires fine-tunings between parameters. Therefore, it seems to be more realistic to consider universal waterfall textures for both Yf and MR, e.g., by the radiative mass generation or the Froggatt-Nielsen mechanism. Moreover, analysis of eigenvalues shows that the lightest mass eigenvalue MR 1 is too light to achieve successful thermal leptogenesis. Although the resonant leptogenesis might be possible, it also requires fine-tunings of parameters.

Rapid detection and identification of N-acetyl-L-cysteine thioethers using constant neutral loss and theoretical multiple reaction monitoring combined with enhanced product-ion scans on a linear ion trap mass spectrometer.

PubMed

Scholz, Karoline; Dekant, Wolfgang; Völkel, Wolfgang; Pähler, Axel

2005-12-01

A sensitive and specific liquid chromatography-mass spectrometry (LC-MS) method based on the combination of constant neutral loss scans (CNL) with product ion scans was developed on a linear ion trap. The method is applicable for the detection and identification of analytes with identical chemical substructures (such as conjugates of xenobiotics formed in biological systems) which give common CNLs. A specific CNL was observed for thioethers of N-acetyl-L-cysteine (mercapturic acids, MA) by LC-MS/MS. MS and HPLC parameters were optimized with 16 MAs available as reference compounds. All of these provided a CNL of 129 Da in the negative-ion mode. To assess sensitivity, a multiple reaction monitoring (MRM) mode with 251 theoretical transitions using the CNL of 129 Da combined with a product ion scan (IDA thMRM) was compared with CNL combined with a product ion scan (IDA CNL). An information-dependent acquisition (IDA) uses a survey scan such as MRM (multiple reaction monitoring) to generate "informations" and starting a second acquisition experiment such as a product ion scan using these "informations." Th-MRM means calculated transitions and not transitions generated from an available standard in the tuning mode. The product ion spectra provide additional information on the chemical structure of the unknown analytes. All MA standards were spiked in low concentrations to rat urines and were detected with both methods with LODs ranging from 60 pmol/mL to 1.63 nmol/mL with IDA thMRM. The expected product ion spectra were observed in urine. Application of this screening method to biological samples indicated the presence of a number of MAs in urine of unexposed rats, and resulted in the identification of 1,4-dihydroxynonene mercapturic acid as one of these MAs by negative and positive product ion spectra. These results show that the developed methods have a high potential to serve as both a prescreen to detect unknown MAs and to identify these analytes in complex matrix.

Ethylene contributes to mir1-mediated maize defense against the phloem-sap sucking insect Rhopalosiphum maidis.

USDA-ARS?s Scientific Manuscript database

Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for providing maize insect resistance1 (mir1), a key endogenous defense sign...

Matt Beard | NREL

Science.gov Websites

. McNichols, J. Gu, A.J. Nozik, A. Sellinger, G. Galli, M.C. Beard, "Tuning colloidal quantum dot band , 15257, 2017, DOI:10.1038/ncomms15257 Y. Yan, R. W. Crisp, J. Gu, B.D. Chernomodik, G.F. Pach, A.R . Marshall, J. A. Turner, M.C. Beard, "Multiple exciton generation for photoelectrochemical hydrogen

Multiple Learning Strategies Project. Small Engine Repair Service. [Regular Vocational. Vol. 2.

ERIC Educational Resources Information Center

Pitts, Jim; And Others

This instructional package is one of two designed for use by regular vocational students in the vocational area of small engine repair service. Contained in this document are forty-nine learning modules organized into eleven units: test equipment; motorcycle; engine removal and replacement; machining; tune-ups; short blocks; storage; filling out…

Arbitrary frequency tunable radio frequency bandpass filter based on nano-patterned Permalloy coplanar waveguide (invited)

NASA Astrophysics Data System (ADS)

Wang, Tengxing; Rahman, B. M. Farid; Peng, Yujia; Xia, Tian; Wang, Guoan

2015-05-01

A well designed coplanar waveguide (CPW) based center frequency tunable bandpass filter (BPF) at 4 GHz enabled with patterned Permalloy (Py) thin film has been implemented. The operating frequency of BPF is tunable with only DC current without the use of any external magnetic field. Electromagnetic bandgap resonators structure is adopted in the BPF and thus external DC current can be applied between the input and output of the filter for tuning of Py permeability. Special configurations of resonators with multiple narrow parallel sections have been considered for larger inductance tenability; the tunability of CPW transmission lines of different widths with patterned Py thin film on the top of the signal lines is compared and measured. Py thin film patterned as bars is deposited on the top of the multiple narrow parallel sections of the designed filter. No extra area is required for the designed filter configuration. Filter is measured and results show that its center frequency could be tuned from 4 GHz to 4.02 GHz when the DC current is applied from 0 mA to 400 mA.

Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions.

PubMed

Weng, Z F; Smidman, M; Jiao, L; Lu, Xin; Yuan, H Q

2016-09-01

Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.

Design and Testing of a Dynamically-Tuned Magnetostrictive Spring with Electrically-Controlled Stiffness

NASA Technical Reports Server (NTRS)

Scheidler, Justin; Asnani, Vivake M.; Dapino, Marcelo J.

2015-01-01

This paper details the development of an electrically-controlled, variable-stiffness spring based on magnetostrictive materials. The device, termed a magnetostrictive Varispring, can be applied as a semi-active vibration isolator or switched stiffness vibration controller for reducing transmitted vibrations. The Varispring is designed using 1D linear models that consider the coupled electrical response, mechanically-induced magnetic diffusion, and the effect of internal mass on dynamic stiffness. Modeling results illustrate that a Terfenol-D-based Varispring has a rise time almost an order of magnitude smaller and a magnetic diffusion cut-off frequency over two orders of magnitude greater than a Galfenol-based Varispring. The results motivate the use of laminated Terfenol-D rods for a greater stiffness tuning range and increased bandwidth. The behavior of a prototype Varispring is examined under vibratory excitation up to 6 MPa and 25 Hz using a dynamic load frame. For this prototype, stiffness is indirectly varied by controlling the excitation current. Preliminary measurements of continuous stiffness tuning via sinusoidal currents up to 1 kHz are presented. The measurements demonstrate that the Young's modulus of the Terfenol-D rod inside the Varispring can be continuously varied by up to 21.9 GPa. The observed stiffness tuning range is relatively constant up to 500 Hz, but significantly decreases thereafter. The stiffness tuning range can be greatly increased by improving the current and force control such that a more consistent current can be applied and the Varispring can be accurately tested at a more optimal bias stress.

The dark side of electroweak naturalness beyond the MSSM

NASA Astrophysics Data System (ADS)

Bélanger, Geneviève; Delaunay, Cédric; Goudelis, Andreas

2015-04-01

Weak scale supersymmetry (SUSY) remains a prime explanation for the radiative stability of the Higgs field. A natural account of the Higgs boson mass, however, strongly favors extensions of the Minimal Supersymmetric Standard Model (MSSM). A plausible option is to introduce a new supersymmetric sector coupled to the MSSM Higgs fields, whose associated states resolve the little hierarchy problem between the third generation soft parameters and the weak scale. SUSY also accomodates a weakly interacting cold dark matter (DM) candidate in the form of a stable neutralino. In minimal realizations, the thus-far null results of direct DM searches, along with the DM relic abundance constraint, introduce a level of fine-tuning as severe as the one due to the SUSY little hierarchy problem. We analyse the generic implications of new SUSY sectors parametrically heavier than the minimal SUSY spectrum, devised to increase the Higgs boson mass, on this "little neutralino DM problem". We focus on the SUSY operator of smallest scaling dimension in an effective field theory description, which modifies the Higgs and DM sectors in a correlated manner. Within this framework, we show that recent null results from the LUX experiment imply a tree-level fine-tuning for gaugino DM which is parametrically at least a few times larger than that of the MSSM. Higgsino DM whose relic abundance is generated through a thermal freeze-out mechanism remains also severely fine-tuned, unless the DM lies below the weak boson pair-production threshold. As in the MSSM, well-tempered gaugino-Higgsino DM is strongly disfavored by present direct detection results.

Tunable dual-channel filter based on the photonic crystal with air defects.

PubMed

Zhao, Xiaodan; Yang, Yibiao; Wen, Jianhua; Chen, Zhihui; Zhang, Mingda; Fei, Hongming; Hao, Yuying

2017-07-01

We propose a tuning filter containing two channels by inserting a defect layer (Air/Si/Air/Si/Air) into a one-dimensional photonic crystal of Si/SiO 2 , which is on the symmetry of the defect. Two transmission peaks (1528.98 and 1564.74 nm) appear in the optical communication S-band and C-band, and the transmittance of these two channels is up to 100%. In addition, this design realizes multi-channel filtering to process large dynamic range or multiple independent signals in the near-infrared band by changing the structure. The tuning range will be enlarged, and the channels can be moved in this range through the easy control of air thickness and incident angle.

Simplified filtered Smith predictor for MIMO processes with multiple time delays.

PubMed

Santos, Tito L M; Torrico, Bismark C; Normey-Rico, Julio E

2016-11-01

This paper proposes a simplified tuning strategy for the multivariable filtered Smith predictor. It is shown that offset-free control can be achieved with step references and disturbances regardless of the poles of the primary controller, i.e., integral action is not explicitly required. This strategy reduces the number of design parameters and simplifies tuning procedure because the implicit integrative poles are not considered for design purposes. The simplified approach can be used to design continuous-time or discrete-time controllers. Three case studies are used to illustrate the advantages of the proposed strategy if compared with the standard approach, which is based on the explicit integrative action. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Monitoring groundwater variation by satellite and implications for in-situ gravity measurements.

PubMed

Fukuda, Yoichi; Yamamoto, Keiko; Hasegawa, Takashi; Nakaegawa, Toshiyuki; Nishijima, Jun; Taniguchi, Makoto

2009-04-15

In order to establish a new technique for monitoring groundwater variations in urban areas, the applicability of precise in-situ gravity measurements and extremely high precision satellite gravity data via GRACE (Gravity Recovery and Climate Experiment) was tested. Using the GRACE data, regional scale water mass variations in four major river basins of the Indochina Peninsula were estimated. The estimated variations were compared with Soil-Vegetation-Atmosphere Transfer Scheme (SVATS) models with a river flow model of 1) globally uniform river velocity, 2) river velocity tuned by each river basin, 3) globally uniform river velocity considering groundwater storage, and 4) river velocity tuned by each river basin considering groundwater storage. Model 3) attained the best fit to the GRACE data, and the model 4) yielded almost the same values. This implies that the groundwater plays an important role in estimating the variation of total terrestrial storage. It also indicates that tuning river velocity, which is based on the in-situ measurements, needs further investigations in combination with the GRACE data. The relationships among GRACE data, SVATS models, and in-situ measurements were also discussed briefly.

BRIEF COMMUNICATION: Electrothermal bistability tuning in a large displacement micro actuator

NASA Astrophysics Data System (ADS)

Gerson, Y.; Krylov, S.; Ilic, B.

2010-11-01

We report on an approach allowing simple yet efficient tuning of the bistability properties in large displacement micro actuators. The devices fabricated from silicon on insulator (SOI) wafers using a deep reactive ion etching (DRIE)-based process incorporate elastic suspension realized as a pair of beams initially curved in-plane and are operated electrostatically by a comb-drive transducer. The curvature of beam and therefore the stability characteristics of the suspension are controlled by passing a current through the suspension and resistive heating the beam material. Experimental results, which are in good agreement with the finite elements model predictions, demonstrate the feasibility of the suggested approach and show that the application of a small tuning current increases the device deflection from 42 to 56 µm, allows adjustment of the critical snap-through and snap-back voltages and makes it possible the control of latching without an additional electrode. The approach can be efficiently implemented in electrical and optical switches and threshold inertial and mass sensors where the use of long displacement actuators with an adjustable bistability range is beneficial.

Ion related problems for the XLS ring

NASA Astrophysics Data System (ADS)

Bozoki, Eva S.; Halama, Henry

1991-10-01

The electron beam in a storage ring collides with the residual gas in the vacuum chamber. As a consequence, low velocity positive ions are produced and trapped in the potential well of the electron beam. They perform stable or unstable oscillations around the beam under the repetitive Coulomb force of the bunches. If not cleared, the captured ions can lead to partial or total neutralization of the beam, causing both a decrease of lifetime and a change in the vertical tunes as well as an increase in the tune spread. It can also cause coherent and incoherent transverse instabilities. An electrostatic clearing electrodes system was designed to keep the neutralization below a desired limit. The location and the geometry of the clearing electrodes as well as the applied clearing voltage is based on the study of the ion production rate, longitudinal velocity of ions in field-free regions and in the dipoles, beam self-electric field, beam potential, critical mass for ion capture in the bunched beam and the bounce frequencies of the ions, tune shift and pressure rise due to trapped ions.

Polarization-tuned Dynamic Color Filters Incorporating a Dielectric-loaded Aluminum Nanowire Array

PubMed Central

Raj Shrestha, Vivek; Lee, Sang-Shin; Kim, Eun-Soo; Choi, Duk-Yong

2015-01-01

Nanostructured spectral filters enabling dynamic color-tuning are saliently attractive for implementing ultra-compact color displays and imaging devices. Realization of polarization-induced dynamic color-tuning via one-dimensional periodic nanostructures is highly challenging due to the absence of plasmonic resonances for transverse-electric polarization. Here we demonstrate highly efficient dynamic subtractive color filters incorporating a dielectric-loaded aluminum nanowire array, providing a continuum of customized color according to the incident polarization. Dynamic color filtering was realized relying on selective suppression in transmission spectra via plasmonic resonance at a metal-dielectric interface and guided-mode resonance for a metal-clad dielectric waveguide, each occurring at their characteristic wavelengths for transverse-magnetic and electric polarizations, respectively. A broad palette of colors, including cyan, magenta, and yellow, has been attained with high transmission beyond 80%, by tailoring the period of the nanowire array and the incident polarization. Thanks to low cost, high durability, and mass producibility of the aluminum adopted for the proposed devices, they are anticipated to be diversely applied to color displays, holographic imaging, information encoding, and anti-counterfeiting. PMID:26211625

Shiver me titin! Elucidating titin's role in shivering thermogenesis.

PubMed

Taylor-Burt, Kari R; Monroy, Jenna; Pace, Cinnamon; Lindstedt, Stan; Nishikawa, Kiisa C

2015-03-01

Shivering frequency scales predictably with body mass and is 10 times higher in a mouse than a moose. The link between shivering frequency and body mass may lie in the tuning of muscle elastic properties. Titin functions as a muscle 'spring', so shivering frequency may be linked to titin's structure. The muscular dystrophy with myositis (mdm) mouse is characterized by a deletion in titin's N2A region. Mice that are homozygous for the mdm mutation have a lower body mass, stiffer gait and reduced lifespan compared with their wild-type and heterozygous siblings. We characterized thermoregulation in these mice by measuring metabolic rate and tremor frequency during shivering. Mutants were heterothermic at ambient temperatures of 20-37°C while wild-type and heterozygous mice were homeothermic. Metabolic rate increased at smaller temperature differentials (i.e. the difference between body and ambient temperatures) in mutants than in non-mutants. The difference between observed tremor frequencies and shivering frequencies predicted by body mass was significantly larger for mutant mice than for wild-type or heterozygous mice, even after accounting for differences in body temperature. Together, the heterothermy in mutants, the increase in metabolic rate at low temperature differentials and the decreased tremor frequency demonstrate the thermoregulatory challenges faced by mice with the mdm mutation. Oscillatory frequency is proportional to the square root of stiffness, and we observed that mutants had lower active muscle stiffness in vitro. The lower tremor frequencies in mutants are consistent with reduced active muscle stiffness and suggest that titin affects the tuning of shivering frequency. © 2015. Published by The Company of Biologists Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shipman, Galen M.

These are the slides for a presentation on programming models in HPC, at the Los Alamos National Laboratory's Parallel Computing Summer School. The following topics are covered: Flynn's Taxonomy of computer architectures; single instruction single data; single instruction multiple data; multiple instruction multiple data; address space organization; definition of Trinity (Intel Xeon-Phi is a MIMD architecture); single program multiple data; multiple program multiple data; ExMatEx workflow overview; definition of a programming model, programming languages, runtime systems; programming model and environments; MPI (Message Passing Interface); OpenMP; Kokkos (Performance Portable Thread-Parallel Programming Model); Kokkos abstractions, patterns, policies, and spaces; RAJA, a systematicmore » approach to node-level portability and tuning; overview of the Legion Programming Model; mapping tasks and data to hardware resources; interoperability: supporting task-level models; Legion S3D execution and performance details; workflow, integration of external resources into the programming model.« less

Multiple Objects Fusion Tracker Using a Matching Network for Adaptively Represented Instance Pairs

PubMed Central

Oh, Sang-Il; Kang, Hang-Bong

2017-01-01

Multiple-object tracking is affected by various sources of distortion, such as occlusion, illumination variations and motion changes. Overcoming these distortions by tracking on RGB frames, such as shifting, has limitations because of material distortions caused by RGB frames. To overcome these distortions, we propose a multiple-object fusion tracker (MOFT), which uses a combination of 3D point clouds and corresponding RGB frames. The MOFT uses a matching function initialized on large-scale external sequences to determine which candidates in the current frame match with the target object in the previous frame. After conducting tracking on a few frames, the initialized matching function is fine-tuned according to the appearance models of target objects. The fine-tuning process of the matching function is constructed as a structured form with diverse matching function branches. In general multiple object tracking situations, scale variations for a scene occur depending on the distance between the target objects and the sensors. If the target objects in various scales are equally represented with the same strategy, information losses will occur for any representation of the target objects. In this paper, the output map of the convolutional layer obtained from a pre-trained convolutional neural network is used to adaptively represent instances without information loss. In addition, MOFT fuses the tracking results obtained from each modality at the decision level to compensate the tracking failures of each modality using basic belief assignment, rather than fusing modalities by selectively using the features of each modality. Experimental results indicate that the proposed tracker provides state-of-the-art performance considering multiple objects tracking (MOT) and KITTIbenchmarks. PMID:28420194

Electromagnetic energy harvesting from a dual-mass pendulum oscillator

NASA Astrophysics Data System (ADS)

Wang, Hongyan; Tang, Jiong

2016-04-01

This paper presents the analysis of a type of vibration energy harvester composed of an electromagnetic pendulum oscillator combined to an elastic main structure. In this study, the elastic main structure connected to the base is considered as a single degree-of-freedom (DOF) spring-mass-damper subsystem. The electromagnetic pendulum oscillator is considered as a dual-mass two-frequency subsystem, which is composed of a hollow bar with a tip winded coil and a magnetic mass with a spring located in the hollow bar. As the pendulum swings, the magnetic mass can move along the axial direction of the bar. Thus, the relative motion between the magnet and the coil induces a wire current. A mathematical model of the coupled system is established. The system dynamics a 1:2:1 internal resonance. Parametric analysis is carried out to demonstrate the effect of the excitation acceleration, excitation frequency, load resistance, and frequency tuning parameters on system performance.

Unification of gauge, family, and flavor symmetries illustrated in gauged SU(12) models

DOE PAGES

Albright, Carl H.; Feger, Robert P.; Kephart, Thomas W.

2016-04-25

In this study, to explain quark and lepton masses and mixing angles, one has to extend the standard model, and the usual practice is to put the quarks and leptons into irreducible representations of discrete groups. We argue that discrete flavor symmetries (and their concomitant problems) can be avoided if we extend the gauge group. In the framework of SU(12) we give explicit examples of models having varying degrees of predictability obtained by scanning over groups and representations and identifying cases with operators contributing to mass and mixing matrices that need little fine- tuning of prefactors. Fitting with quark andmore » lepton masses run to the GUT scale and known mixing angles allows us to make predictions for the neutrino masses and hierarchy, the octant of the atmospheric mixing angle, leptonic CP violation, Majorana phases, and the effective mass observed in neutrinoless double beta decay.« less

Ultra-thin smart acoustic metasurface for low-frequency sound insulation

NASA Astrophysics Data System (ADS)

Zhang, Hao; Xiao, Yong; Wen, Jihong; Yu, Dianlong; Wen, Xisen

2016-04-01

Insulating low-frequency sound is a conventional challenge due to the high areal mass required by mass law. In this letter, we propose a smart acoustic metasurface consisting of an ultra-thin aluminum foil bonded with piezoelectric resonators. Numerical and experimental results show that the metasurface can break the conventional mass law of sound insulation by 30 dB in the low frequency regime (<1000 Hz), with an ultra-light areal mass density (<1.6 kg/m2) and an ultra-thin thickness (1000 times smaller than the operating wavelength). The underlying physical mechanism of such extraordinary sound insulation performance is attributed to the infinite effective dynamic mass density produced by the smart resonators. It is also demonstrated that the excellent sound insulation property can be conveniently tuned by simply adjusting the external circuits instead of modifying the structure of the metasurface.

New Gogny interaction suitable for astrophysical applications

NASA Astrophysics Data System (ADS)

Gonzalez-Boquera, C.; Centelles, M.; Viñas, X.; Robledo, L. M.

2018-04-01

The D1 family of parametrizations of the Gogny interaction commonly suffers from a rather soft neutron matter equation of state that leads to maximal masses of neutron stars well below the observational value of two solar masses. We propose a reparametrization scheme that preserves the good properties of the Gogny force but allows one to tune the density dependence of the symmetry energy, which, in turn, modifies the predictions for the maximum stellar mass. The scheme works well for D1M, and leads to a new parameter set, dubbed D1M*. In the neutron-star domain, D1M* predicts a maximal mass of two solar masses and global properties of the star in harmony with those obtained with the SLy4 Skyrme interaction. By means of a set of selected calculations in finite nuclei, we check that D1M* performs comparably well to D1M in several aspects of nuclear structure in nuclei.

On developing an optimal design procedure for a bimorph piezoelectric cantilever energy harvester under a predefined volume

NASA Astrophysics Data System (ADS)

Aboulfotoh, Noha; Twiefel, Jens

2018-06-01

A typical vibration harvester is tuned to operate at resonance in order to maximize the power output. There are many design parameter sets for tuning the harvester to a specific frequency, even for simple geometries. This work studies the impact of the geometrical parameters on the harvested power while keeping the resonance frequency constant in order to find the combination of the parameters that optimizes the power under a predefined volume. A bimorph piezoelectric cantilever is considered for the study. It consists of two piezoelectric layers and a middle non-piezoelectric layer and holds a tip mass. A theoretical model was derived to obtain the system parameters and the power as functions of the design parameters. Formulas for the optimal load resistance that provide maximum power capability at resonance and anti-resonance frequency were derived. The influence of the width on the power is studied, considering a constant mass ratio (between the tip mass and the mass of the beam). This keeps the resonance frequency constant while changing the width. The influence of the ratio between the thickness of the middle layer and that of the piezoelectric layer is also studied. It is assumed that the total thickness of the cantilever is constant and the middle layer has the same mechanical properties (elasticity and density) as the piezoelectric layer. This keeps the resonance frequency constant while changing the ratio between the thicknesses. Finally, the influence of increasing the free length as well as of increasing the mass ratio on the power is investigated. This is done by first, increasing each of them individually and secondly, by increasing each of them simultaneously while increasing the total thickness under the condition of maintaining a constant resonance frequency. Based on the analysis of these influences, recommendations as to how to maximize the geometrical parameters within the available volume and mass are presented.

Determination of muon momentum in the MicroBooNE LArTPC using an improved model of multiple Coulomb scattering

NASA Astrophysics Data System (ADS)

Abratenko, P.; Acciarri, R.; Adams, C.; An, R.; Anthony, J.; Asaadi, J.; Auger, M.; Bagby, L.; Balasubramanian, S.; Baller, B.; Barnes, C.; Barr, G.; Bass, M.; Bay, F.; Bishai, M.; Blake, A.; Bolton, T.; Bugel, L.; Camilleri, L.; Caratelli, D.; Carls, B.; Castillo Fernandez, R.; Cavanna, F.; Chen, H.; Church, E.; Cianci, D.; Cohen, E.; Collin, G. H.; Conrad, J. M.; Convery, M.; Crespo-Anadón, J. I.; Del Tutto, M.; Devitt, D.; Dytman, S.; Eberly, B.; Ereditato, A.; Escudero Sanchez, L.; Esquivel, J.; Fleming, B. T.; Foreman, W.; Furmanski, A. P.; Garcia-Gamez, D.; Garvey, G. T.; Genty, V.; Goeldi, D.; Gollapinni, S.; Graf, N.; Gramellini, E.; Greenlee, H.; Grosso, R.; Guenette, R.; Hackenburg, A.; Hamilton, P.; Hen, O.; Hewes, J.; Hill, C.; Ho, J.; Horton-Smith, G.; Huang, E.-C.; James, C.; de Vries, J. Jan; Jen, C.-M.; Jiang, L.; Johnson, R. A.; Joshi, J.; Jostlein, H.; Kaleko, D.; Kalousis, L. N.; Karagiorgi, G.; Ketchum, W.; Kirby, B.; Kirby, M.; Kobilarcik, T.; Kreslo, I.; Laube, A.; Li, Y.; Lister, A.; Littlejohn, B. R.; Lockwitz, S.; Lorca, D.; Louis, W. C.; Luethi, M.; Lundberg, B.; Luo, X.; Marchionni, A.; Mariani, C.; Marshall, J.; Martinez Caicedo, D. A.; Meddage, V.; Miceli, T.; Mills, G. B.; Moon, J.; Mooney, M.; Moore, C. D.; Mousseau, J.; Murrells, R.; Naples, D.; Nienaber, P.; Nowak, J.; Palamara, O.; Paolone, V.; Papavassiliou, V.; Pate, S. F.; Pavlovic, Z.; Piasetzky, E.; Porzio, D.; Pulliam, G.; Qian, X.; Raaf, J. L.; Rafique, A.; Rochester, L.; von Rohr, C. Rudolf; Russell, B.; Schmitz, D. W.; Schukraft, A.; Seligman, W.; Shaevitz, M. H.; Sinclair, J.; Snider, E. L.; Soderberg, M.; Söldner-Rembold, S.; Soleti, S. R.; Spentzouris, P.; Spitz, J.; St. John, J.; Strauss, T.; Szelc, A. M.; Tagg, N.; Terao, K.; Thomson, M.; Toups, M.; Tsai, Y.-T.; Tufanli, S.; Usher, T.; Van de Water, R. G.; Viren, B.; Weber, M.; Wickremasinghe, D. A.; Wolbers, S.; Wongjirad, T.; Woodruff, K.; Yang, T.; Yates, L.; Zeller, G. P.; Zennamo, J.; Zhang, C.

2017-10-01

We discuss a technique for measuring a charged particle's momentum by means of multiple Coulomb scattering (MCS) in the MicroBooNE liquid argon time projection chamber (LArTPC). This method does not require the full particle ionization track to be contained inside of the detector volume as other track momentum reconstruction methods do (range-based momentum reconstruction and calorimetric momentum reconstruction). We motivate use of this technique, describe a tuning of the underlying phenomenological formula, quantify its performance on fully contained beam-neutrino-induced muon tracks both in simulation and in data, and quantify its performance on exiting muon tracks in simulation. Using simulation, we have shown that the standard Highland formula should be re-tuned specifically for scattering in liquid argon, which significantly improves the bias and resolution of the momentum measurement. With the tuned formula, we find agreement between data and simulation for contained tracks, with a small bias in the momentum reconstruction and with resolutions that vary as a function of track length, improving from about 10% for the shortest (one meter long) tracks to 5% for longer (several meter) tracks. For simulated exiting muons with at least one meter of track contained, we find a similarly small bias, and a resolution which is less than 15% for muons with momentum below 2 GeV/c. Above 2 GeV/c, results are given as a first estimate of the MCS momentum measurement capabilities of MicroBooNE for high momentum exiting tracks.

Determination of muon momentum in the MicroBooNE LArTPC using an improved model of multiple Coulomb scattering

DOE PAGES

Abratenko, P.

2017-10-18

Here, we discuss a technique for measuring a charged particle's momentum by means of multiple Coulomb scattering (MCS) in the MicroBooNE liquid argon time projection chamber (LArTPC). This method does not require the full particle ionization track to be contained inside of the detector volume as other track momentum reconstruction methods do (range-based momentum reconstruction and calorimetric momentum reconstruction). We motivate use of this technique, describe a tuning of the underlying phenomenological formula, quantify its performance on fully contained beam-neutrino-induced muon tracks both in simulation and in data, and quantify its performance on exiting muon tracks in simulation. Using simulation,more » we have shown that the standard Highland formula should be re-tuned specifically for scattering in liquid argon, which significantly improves the bias and resolution of the momentum measurement. With the tuned formula, we find agreement between data and simulation for contained tracks, with a small bias in the momentum reconstruction and with resolutions that vary as a function of track length, improving from about 10% for the shortest (one meter long) tracks to 5% for longer (several meter) tracks. For simulated exiting muons with at least one meter of track contained, we find a similarly small bias, and a resolution which is less than 15% for muons with momentum below 2 GeV/c. Above 2 GeV/c, results are given as a first estimate of the MCS momentum measurement capabilities of MicroBooNE for high momentum exiting tracks.« less

Determination of muon momentum in the MicroBooNE LArTPC using an improved model of multiple Coulomb scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abratenko, P.

Here, we discuss a technique for measuring a charged particle's momentum by means of multiple Coulomb scattering (MCS) in the MicroBooNE liquid argon time projection chamber (LArTPC). This method does not require the full particle ionization track to be contained inside of the detector volume as other track momentum reconstruction methods do (range-based momentum reconstruction and calorimetric momentum reconstruction). We motivate use of this technique, describe a tuning of the underlying phenomenological formula, quantify its performance on fully contained beam-neutrino-induced muon tracks both in simulation and in data, and quantify its performance on exiting muon tracks in simulation. Using simulation,more » we have shown that the standard Highland formula should be re-tuned specifically for scattering in liquid argon, which significantly improves the bias and resolution of the momentum measurement. With the tuned formula, we find agreement between data and simulation for contained tracks, with a small bias in the momentum reconstruction and with resolutions that vary as a function of track length, improving from about 10% for the shortest (one meter long) tracks to 5% for longer (several meter) tracks. For simulated exiting muons with at least one meter of track contained, we find a similarly small bias, and a resolution which is less than 15% for muons with momentum below 2 GeV/c. Above 2 GeV/c, results are given as a first estimate of the MCS momentum measurement capabilities of MicroBooNE for high momentum exiting tracks.« less

Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds

PubMed Central

Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedl, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

2016-01-01

Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination. DOI: http://dx.doi.org/10.7554/eLife.15675.001 PMID:27402384

A Measurement and Simulation Based Methodology for Cache Performance Modeling and Tuning

NASA Technical Reports Server (NTRS)

Waheed, Abdul; Yan, Jerry; Saini, Subhash (Technical Monitor)

1998-01-01

We present a cache performance modeling methodology that facilitates the tuning of uniprocessor cache performance for applications executing on shared memory multiprocessors by accurately predicting the effects of source code level modifications. Measurements on a single processor are initially used for identifying parts of code where cache utilization improvements may significantly impact the overall performance. Cache simulation based on trace-driven techniques can be carried out without gathering detailed address traces. Minimal runtime information for modeling cache performance of a selected code block includes: base virtual addresses of arrays, virtual addresses of variables, and loop bounds for that code block. Rest of the information is obtained from the source code. We show that the cache performance predictions are as reliable as those obtained through trace-driven simulations. This technique is particularly helpful to the exploration of various "what-if' scenarios regarding the cache performance impact for alternative code structures. We explain and validate this methodology using a simple matrix-matrix multiplication program. We then apply this methodology to predict and tune the cache performance of two realistic scientific applications taken from the Computational Fluid Dynamics (CFD) domain.

Enhanced Photoelectrochemical Water Splitting Behaviour of Tuned Band Gap CdSe QDs Sensitized LaB₆.

PubMed

Babu, M Soban; Sivanantham, A; Chakravarthi, B Barath; Kannan, R Sujith; Panda, Subhendu K; Berchmans, L John; Arya, S B; Sreedhar, Gosipathala

2017-01-01

We report the fabrication of tuned band gap quantum dots sensitized LaB₆ hybrid nanostructures and their application as a photoanode for photoelectrochemical water splitting. The lanthanum hexaboride (LaB₆) obtained by molten salt electrolysis method is sensitized with different sized CdSe quantum dots, which form a multiple-level hierarchical heterostructure and such design enhance the light absorption and charge carrier separation, which in turn showed higher photocurrent density compared to that of pristine LaB₆. When LaB₆ is sensitized with CdSe quantum dots of different band gaps, which have the absorption in the green and red (530 and 605 nm) regions in visible light, developed a ten times higher photocurrent density (11.0 mA cm(−2)) compared to that of pristine LaB6 (0.5 mA cm(−2) at 0.75 V vs. Ag/AgCl) in 1 M Na₂S electrolyte under illumination. These results prove that the tuned band gap quantum dots sensitized LaB₆ heterostructures are an ideal candidate for a photoanode in solar water splitting applications.

Post-inscription tuning of multicore fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Lindley, Emma Y.; Min, Seong-sik; Leon-Saval, Sergio G.; Bland-Hawthorn, Joss

2016-07-01

Fiber Bragg gratings are used in astronomy for their ability to suppress narrow atmospheric emission lines of temporally varying brightness before the light is dispersed. These gratings can only operate in a single-mode fiber as the suppressed wavelength depends on mode velocity in the core. Recent experiments with fibers containing multiple single-moded cores have demonstrated the potential for inscribing identical gratings across all cores in a single pass. We have already improved the uniformity of gratings in 7-core fibers via modifications to the writing process; further progress can be achieved by tuning the gratings of the outer and inner cores relative to one another. Our eventual goal is to make the entire fiber suppress one wavelength to a depth of 30 dB or greater. By coating the fiber in a heat-conductive material with a high expansion coefficient, we can examine the effects of temperature and strain on the spectral response of each core. In this paper we present methods and results from experiments concerning the post-write tuning of gratings in multicore fibers.

Failed Supernovae Explain the Compact Remnant Mass Function

NASA Astrophysics Data System (ADS)

Kochanek, C. S.

2014-04-01

One explanation for the absence of higher mass red supergiants (16.5 M ⊙ <~ M <~ 25 M ⊙) as the progenitors of Type IIP supernovae (SNe) is that they die in failed SNe creating black holes. Simulations show that such failed SNe still eject their hydrogen envelopes in a weak transient, leaving a black hole with the mass of the star's helium core (5-8 M ⊙). Here we show that this naturally explains the typical masses of observed black holes and the gap between neutron star and black hole masses without any fine-tuning of stellar mass loss, binary mass transfer, or the SN mechanism, beyond having it fail in a mass range where many progenitor models have density structures that make the explosions more likely to fail. There is no difficulty including this ~20% population of failed SNe in any accounting of SN types over the progenitor mass function. And, other than patience, there is no observational barrier to either detecting these black hole formation events or limiting their rates to be well below this prediction.

Observing mergers of nonspinning black-hole binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

McWilliams, Sean T.; Baker, John G.; Kelly, Bernard J.

2010-07-15

Advances in the field of numerical relativity now make it possible to calculate the final, most powerful merger phase of binary black-hole coalescence for generic binaries. The state of the art has advanced well beyond the equal-mass case into the unequal-mass and spinning regions of parameter space. We present a study of the nonspinning portion of parameter space, primarily using an analytic waveform model tuned to available numerical data, with an emphasis on observational implications. We investigate the impact of varied mass-ratio on merger signal-to-noise ratios for several detectors, and compare our results with expectations from the test-mass limit. Wemore » note a striking similarity of the waveform phasing of the merger waveform across the available mass ratios. Motivated by this, we calculate the match between our 1:1 (equal-mass) and 4:1 mass-ratio waveforms during the merger as a function of location on the source sky, using a new formalism for the match that accounts for higher harmonics. This is an indicator of the amount of degeneracy in mass-ratio for mergers of moderate-mass-ratio systems.« less

Method of making an InAsSb/InAsSbP diode lasers

DOEpatents

Razeghi, Manijeh

1997-01-01

InAsSb/InAsSbP/InAs Double Heterostructures (DH) and Separate Confinement Heterostructure Multiple Quantum Well (SCH-MQW) structures are taught wherein the ability to tune to a specific wavelength within 3 .mu.m to 5 .mu.m is possible by varying the ratio of As:Sb in the active layer.

Multi-functional micromotor: microfluidic fabrication and water treatment application.

PubMed

Chen, Anqi; Ge, Xue-Hui; Chen, Jian; Zhang, Liyuan; Xu, Jian-Hong

2017-12-05

Micromotors are important for a wide variety of applications. Here, we develop a microfluidic approach for one-step fabrication of a Janus self-propelled micromotor with multiple functions. By fine tuning the fabrication parameters and loading functional nanoparticles, our micromotor reaches a high speed and achieves an oriented function to promote the water purification efficiency and recycling process.

Potassium Homeostasis: The Knowns, the Unknowns, and the Health Benefits

PubMed Central

Youn, Jang H.

2017-01-01

Potassium homeostasis has a very high priority because of its importance for membrane potential. Although extracellular K+ is only 2% of total body K+, our physiology was evolutionarily tuned for a high-K+, low-Na+ diet. We review how multiple systems interface to accomplish fine K+ balance and the consequences for health and disease. PMID:28202621

Ranking and the Multiplication of Reputation: Reflections from the Frontier of Globalizing Higher Education

ERIC Educational Resources Information Center

Collins, Francis L.; Park, Gil-Sung

2016-01-01

Over the last two decades, enumeration has become a critical force in crafting the governmentalities of globalizing higher education. Whether in the glossy Web sites and documentation of the world's "top universities" or in more fine-tuned regional and subject guides, accreditation schemes, journal metrics or h-indexes, technologies for…

Relaxion cosmology and the price of fine-tuning

NASA Astrophysics Data System (ADS)

Di Chiara, Stefano; Kannike, Kristjan; Marzola, Luca; Racioppi, Antonio; Raidal, Martti; Spethmann, Christian

2016-05-01

The relaxion scenario presents an intriguing extension of the standard model in which the particle introduced to solve to the strong C P problem, the axion, also achieves the dynamical relaxation of the Higgs boson mass term. In this work we complete this framework by proposing a scenario of inflationary cosmology that is consistent with all the observational constraints: the relaxion hybrid inflation with an asymmetric waterfall. In our scheme, the vacuum energy of the inflaton drives inflation in a natural way while the relaxion slow rolls. The constraints on the present inflationary observables are then matched through a subsequent inflationary epoch driven by the inflaton. We quantify the amount of fine-tuning of the proposed inflation scenario, concluding that the inflaton sector severely decreases the naturalness of the theory.

Tuning the ultrafast photodissociation dynamics of CH3Br on ultrathin MgO films by reducing the layer thickness to the 2D limit

NASA Astrophysics Data System (ADS)

Vaida, Mihai E.; Bernhardt, Thorsten M.

2017-11-01

The femtosecond-laser induced photodissociation of CH3Br adsorbed at sub-monolayer coverage on a solid surface was investigated by time-resolved pump-probe mass spectrometry. To tune the interaction of the CH3Br molecules with the substrate, an Mo(1 0 0) surface was covered with ultrathin insulating MgO layers of variable thickness. By gradually decreasing the magnesia layer thickness to the 2D limit the photodissociation dynamics observed by detection of the methyl fragment indicates an energetic lowering of the relevant methyl bromide excited states due to the increasing spatial proximity of the metallic support. Potential orientational effects of the methyl bromide adsorption geometry are also considered.

Dynamical mass and multiplicity constraints on co-orbital bodies around stars

NASA Astrophysics Data System (ADS)

Veras, Dimitri; Marsh, Thomas R.; Gänsicke, Boris T.

2016-09-01

Objects transiting near or within the disruption radius of both main-sequence (e.g. KOI 1843) and white dwarf (WD 1145+017) stars are now known. Upon fragmentation or disintegration, these planets or asteroids may produce co-orbital configurations of nearly equal mass objects. However, as evidenced by the co-orbital objects detected by transit photometry in the WD 1145+017 system, these bodies are largely unconstrained in size, mass, and total number (multiplicity). Motivated by potential future similar discoveries, we perform N-body simulations to demonstrate if and how debris masses and multiplicity may be bounded due to second-to-minute deviations and the resulting accumulated phase shifts in the osculating orbital period amongst multiple co-orbital equal point masses. We establish robust lower and upper mass bounds as a function of orbital period deviation, but find the constraints on multiplicity to be weak. We also quantify the fuzzy instability boundary, and show that mutual collisions occur in less than 5, 10, and 20 per cent of our simulations for masses of 1021, 1022, and 1023 kg. Our results may provide useful initial rough constraints on other stellar systems with multiple co-orbital bodies.

Development and application of the modal space self-tuning regulator

NASA Astrophysics Data System (ADS)

Schultze, John Francis

The control and reduction of vibration of flexible structures is currently an area of much research and concern in the aerospace and automotive industries. Often these systems are idealized as discrete systems with a finite number of degrees of freedom. Traditional active control approaches have attempted either to identify the complete system and design an appropriate controller or; use an ad-hoc set of single degree of freedom controllers. Both methods have limitations. The former requires great computational and control design effort. This approach also attempts to reduce the vibration across the complete spectrum as opposed to applying control effort only to the problematic mode(s). The latter method is often limited by its inability to address the structural coupling inherent in these systems. The Modal Space Self Tuning Regulator (MSSTR) method proposed in this research addresses both of these problems as well as changes in the structural properties of a system. The control problem is approached in a two stage effort, decoupling and adaptive control. The structure's motion is decoupled through the Modified Reciprocal Modal Vector method. The control is then implemented in modal space as a new acceleration feedback based, single degree of freedom, form of the Self Tuning Regulator. The range of application of this controller in terms of maximum additive damping, actuator location sensitivity, and discrete and continuous system mass changes are investigated. Also, the behavior of the internal controller parameters are studied for the extension of this method to system monitoring and damage detection. Proof of the numeric stability of the controller in the ideal case is presented as well as its practical implementation issues. This control approach was shown to be effective for the cases of specified damping increases up to 10 dB, several actuator locations, three discrete mass perturbations and several continuous mass change cases. There appears to be little dependence on the actuator position until the additive damping limit is reached. The discrete mass change tests investigate both increases and reductions in the effective moving mass of the system. The controller performed well in all cases investigated achieving a minimum of 7 dB and up to 15 dB of attenuation. The continuous mass change cases, modeling tool-wear, fuel consumption, or other time varying phenomena, show good convergence behavior of the system model and the accompanying regulator law parameters. This validates the controller for its implementation in a rapidly changing system. The MSSTR performed well in several varied test cases, showing both insensitivity to actuator location and resilience to changing system parameters. Extensions to multi-input, multi-mode control appears within ready grasp.

An Evaluation of Unit and ½ Mass Correction Approaches as a ...

EPA Pesticide Factsheets

Rare earth elements (REE) and certain alkaline earths can produce M+2 interferences in ICP-MS because they have sufficiently low second ionization energies. Four REEs (150Sm, 150Nd, 156Gd and 156Dy) produce false positives on 75As and 78Se and 132Ba can produce a false positive on 66Zn. Currently, US EPA Method 200.8 does not address these as sources of false positives. Additionally, these M+2 false positives are typically enhanced if collision cell technology is utilized to reduce polyatomic interferences associated with ICP-MS detection. A preliminary evaluation indicates that instrumental tuning conditions can impact the observed M+2/M+1 ratio and in turn the false positives generated on Zn, As and Se. Both unit and ½ mass approaches will be evaluated to correct for these false positives relative to the benchmark concentrations estimates from a triple quadrupole ICP-MS using standard solutions. The impact of matrix on these M+2 corrections will be evaluated over multiple analysis days with a focus on evaluating internal standards that mirror the matrix induced shifts in the M+2 ion transmission. The goal of this evaluation is to move away from fixed M+2 corrective approaches and move towards sample specific approaches that mimic the sample matrix induced variability while attempting to address intra-day variability of the M+2 correction factors through the use of internal standards. Oral Presentation via webinar for EPA Laboratory Technical Informati

Translation system engineering in Escherichia coli enhances non-canonical amino acid incorporation into proteins.

PubMed

Gan, Rui; Perez, Jessica G; Carlson, Erik D; Ntai, Ioanna; Isaacs, Farren J; Kelleher, Neil L; Jewett, Michael C

2017-05-01

The ability to site-specifically incorporate non-canonical amino acids (ncAAs) into proteins has made possible the study of protein structure and function in fundamentally new ways, as well as the bio synthesis of unnatural polymers. However, the task of site-specifically incorporating multiple ncAAs into proteins with high purity and yield continues to present a challenge. At the heart of this challenge lies the lower efficiency of engineered orthogonal translation system components compared to their natural counterparts (e.g., translation elements that specifically use a ncAA and do not interact with the cell's natural translation apparatus). Here, we show that evolving and tuning expression levels of multiple components of an engineered translation system together as a whole enhances ncAA incorporation efficiency. Specifically, we increase protein yield when incorporating multiple p-azido-phenylalanine(pAzF) residues into proteins by (i) evolving the Methanocaldococcus jannaschii p-azido-phenylalanyl-tRNA synthetase anti-codon binding domain, (ii) evolving the elongation factor Tu amino acid-binding pocket, and (iii) tuning the expression of evolved translation machinery components in a single vector. Use of the evolved translation machinery in a genomically recoded organism lacking release factor one enabled enhanced multi-site ncAA incorporation into proteins. We anticipate that our approach to orthogonal translation system development will accelerate and expand our ability to site-specifically incorporate multiple ncAAs into proteins and biopolymers, advancing new horizons for synthetic and chemical biotechnology. Biotechnol. Bioeng. 2017;114: 1074-1086. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

An improved design method of a tuned mass damper for an in-service footbridge

NASA Astrophysics Data System (ADS)

Shi, Weixing; Wang, Liangkun; Lu, Zheng

2018-03-01

Tuned mass damper (TMD) has a wide range of applications in the vibration control of footbridges. However, the traditional engineering design method may lead to a mistuned TMD. In this paper, an improved TMD design method based on the model updating is proposed. Firstly, the original finite element model (FEM) is studied and the natural characteristics of the in-service or newly built footbridge is identified by field test, and then the original FEM is updated. TMD is designed according to the new updated FEM, and it is optimized according to the simulation on vibration control effects. Finally, the installation and field measurement of TMD are carried out. The improved design method can be applied to both in-service and newly built footbridges. This paper illustrates the improved design method with an engineering example. The frequency identification results of field test and original FEM show that there is a relatively large difference between them. The TMD designed according to the updated FEM has better vibration control effect than the TMD designed according to the original FEM. The site test results show that TMD has good effect on controlling human-induced vibrations.

The Mobius domain wall fermion algorithm

DOE PAGES

Brower, Richard C.; Neff, Harmut; Orginos, Kostas

2017-07-22

We present a review of the properties of generalized domain wall Fermions, based on a (real) Möbius transformation on the Wilson overlap kernel, discussing their algorithmic efficiency, the degree of explicit chiral violations measured by the residual mass (m res) and the Ward–Takahashi identities. The Möbius class interpolates between Shamir’s domain wall operator and Boriçi’s domain wall implementation of Neuberger’s overlap operator without increasing the number of Dirac applications per conjugate gradient iteration. A new scaling parameter (α) reduces chiral violations at finite fifth dimension (L s) but yields exactly the same overlap action in the limit L s →more » ∞ . Through the use of 4d Red/Black preconditioning and optimal tuning for the scaling α(L s), we show that chiral symmetry violations are typically reduced by an order of magnitude at fixed Ls . Here, we argue that the residual mass for a tuned Möbius algorithm with α = O(1/L s γ) for γ < 1 will eventually fall asymptotically as m res = O(1/L s 1+γ) in the case of a 5D Hamiltonian with out a spectral gap.« less

The Mobius domain wall fermion algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brower, Richard C.; Neff, Harmut; Orginos, Kostas

We present a review of the properties of generalized domain wall Fermions, based on a (real) Möbius transformation on the Wilson overlap kernel, discussing their algorithmic efficiency, the degree of explicit chiral violations measured by the residual mass (m res) and the Ward–Takahashi identities. The Möbius class interpolates between Shamir’s domain wall operator and Boriçi’s domain wall implementation of Neuberger’s overlap operator without increasing the number of Dirac applications per conjugate gradient iteration. A new scaling parameter (α) reduces chiral violations at finite fifth dimension (L s) but yields exactly the same overlap action in the limit L s →more » ∞ . Through the use of 4d Red/Black preconditioning and optimal tuning for the scaling α(L s), we show that chiral symmetry violations are typically reduced by an order of magnitude at fixed Ls . Here, we argue that the residual mass for a tuned Möbius algorithm with α = O(1/L s γ) for γ < 1 will eventually fall asymptotically as m res = O(1/L s 1+γ) in the case of a 5D Hamiltonian with out a spectral gap.« less

Passive vibration suppression using inerters for a multi-storey building structure

NASA Astrophysics Data System (ADS)

Zhang, Sara Ying; Jiang, Jason Zheng; Neild, Simon

2016-09-01

This paper investigates the use of inerters for vibration suppression of a multistorey building structure. The inerter was proposed as a two-terminal replacement for the mass element, with the property that the applied force is proportional to the relative acceleration across its terminals. It completes the force-current mechanical-electrical network analogy, providing the mechanical equivalent to a capacitor. Thus allows all passive mechanical impedances to be synthesised. The inerter has been used in Formula 1 racing cars and applications to various systems such as vehicle suspension have been identified. Several devices that incoporate inerter(s), as well as spring(s) and damper(s), have also been identified for vibration suppression of building structures. These include the tuned inerter damper (TID) and the tuned viscous mass damper (TVMD). In this paper, a three-storey building model with an absorber located at the bottom subjected to base excitation is studied. Four simple absorber layouts, in terms of how spring, damper and inerter components should be arranged, have been studied. In order to minimise the maximum relative displacement of the building, the optimum parameter values for each of the layouts have been obtained with respect to the inerter's size.

Polarized Fermi Condensates with Unequal Masses: Tuning the Tricritical Point

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parish, M. M.; Marchetti, F. M.; Simons, B. D.

We consider a two-component atomic Fermi gas within a mean-field, single-channel model, where both the mass and population of each component are unequal. We show that the tricritical point at zero temperature evolves smoothly from the BEC to BCS side of the resonance as a function of mass ratio r. We find that the interior gap state proposed by Liu and Wilczek is always unstable to phase separation, while the breached pair state with one Fermi surface for the excess fermions exhibits differences in its density of states and pair correlation functions depending on which side of the resonance itmore » lies. Finally, we show that, when r > or appro. 3.95, the finite-temperature phase diagram of trapped gases at unitarity becomes topologically distinct from the equal mass system.« less

Application of bias voltage to tune the resonant frequency of membrane-based electroactive polymer energy harvesters

NASA Astrophysics Data System (ADS)

Dong, Lin; Grissom, Michael; Fisher, Frank T.

2016-05-01

Vibration-based energy harvesting has been widely investigated to as a means to generate low levels of electrical energy for applications such as wireless sensor networks. However, for optimal performance it is necessary to ensure that resonant frequencies of the device match the ambient vibration frequencies for maximum energy harvested. Here a novel resonant frequency tuning approach is proposed by applying a bias voltage to a pre-stretched electroactive polymer (EAP) membrane, such that the resulting changes in membrane tension can tune the device to match the environmental vibration source. First, a material model which accounts for the change in properties due to the pre-stretch of a VHB 4910 EAP membrane is presented. The effect of the bias voltage on the EAP membrane, which induces an electrostatic pressure and corresponding reduction in membrane thickness, are then determined. The FEM results from ANSYS agree well with an analytical hyperelastic model of the activation response of the EAP membrane. Lastly, through a mass-loaded circular membrane vibration model, the effective resonant frequency of the energy harvester can be determined as a function of changes in membrane tension due to the applied bias voltage. In the case of an EAP membrane, pre-stretch contributes to the pre-stretch stiffness of the system while the applied bias voltage contributes to a change in bias voltage stiffness of the membrane. Preliminary experiments verified the resonant frequencies corresponding to the bias voltages predicted from the appropriate models. The proposed bias voltage tuning approach for the EAP membrane may provide a novel tuning strategy to enable energy harvesting from various ambient vibration sources in various application environments.

Quark mass variations of nuclear forces, BBN, and all that

NASA Astrophysics Data System (ADS)

Meissner, Ulf-G.

2014-03-01

In this talk, I discuss the modifications of the nuclear forces due to variations of the light quark masses and of the fine structure constant. This is based on the chiral nuclear effective field theory, that successfully describes a large body of data. The generation of the light elements in the Big Bang Nucleosynthesis provides important constraints on these modifications. In addition, I discuss the role of the anthropic principle in the triple-alpha process that underlies carbon and oxygen generation in hot stars. It appears that a fine-tuning of the quark masses and the fine structure constant within 2 to 3 per cent is required to make life on Earth viable. Supported in part by DFG, HGF and the BMBF.

The representation of sound localization cues in the barn owl's inferior colliculus

PubMed Central

Singheiser, Martin; Gutfreund, Yoram; Wagner, Hermann

2012-01-01

The barn owl is a well-known model system for studying auditory processing and sound localization. This article reviews the morphological and functional organization, as well as the role of the underlying microcircuits, of the barn owl's inferior colliculus (IC). We focus on the processing of frequency and interaural time (ITD) and level differences (ILD). We first summarize the morphology of the sub-nuclei belonging to the IC and their differentiation by antero- and retrograde labeling and by staining with various antibodies. We then focus on the response properties of neurons in the three major sub-nuclei of IC [core of the central nucleus of the IC (ICCc), lateral shell of the central nucleus of the IC (ICCls), and the external nucleus of the IC (ICX)]. ICCc projects to ICCls, which in turn sends its information to ICX. The responses of neurons in ICCc are sensitive to changes in ITD but not to changes in ILD. The distribution of ITD sensitivity with frequency in ICCc can only partly be explained by optimal coding. We continue with the tuning properties of ICCls neurons, the first station in the midbrain where the ITD and ILD pathways merge after they have split at the level of the cochlear nucleus. The ICCc and ICCls share similar ITD and frequency tuning. By contrast, ICCls shows sigmoidal ILD tuning which is absent in ICCc. Both ICCc and ICCls project to the forebrain, and ICCls also projects to ICX, where space-specific neurons are found. Space-specific neurons exhibit side peak suppression in ITD tuning, bell-shaped ILD tuning, and are broadly tuned to frequency. These neurons respond only to restricted positions of auditory space and form a map of two-dimensional auditory space. Finally, we briefly review major IC features, including multiplication-like computations, correlates of echo suppression, plasticity, and adaptation. PMID:22798945

Multi-turn multi-gap transmission line resonators - Concept, design and first implementation at 4.7T and 7T.

PubMed

Frass-Kriegl, Roberta; Laistler, Elmar; Hosseinnezhadian, Sajad; Schmid, Albrecht Ingo; Moser, Ewald; Poirier-Quinot, Marie; Darrasse, Luc; Ginefri, Jean-Christophe

2016-12-01

A novel design scheme for monolithic transmission line resonators (TLRs) is presented - the multi-turn multi-gap TLR (MTMG-TLR) design. The MTMG-TLR design enables the construction of TLRs with multiple turns and multiple gaps. This presents an additional degree of freedom in tuning self-resonant TLRs, as their resonance frequency is fully determined by the coil geometry (e.g. diameter, number of turns, conductor width, etc.). The novel design is evaluated at 4.7T and 7T by simulations and experiments, where it is demonstrated that MTMG-TLRs can be used for MRI, and that the B 1 distribution of MTMG-TLRs strongly depends on the number and distribution of turns. A comparison to conventional loop coils revealed that the B 1 performance of MTMG-TLRs is comparable to a loop coil with the same mean diameter; however, lower 10g SAR values were found for MTMG-TLRs. The MTMG-TLR design is expected to bring most benefits at high static field, where it allows for independent size and frequency selection, which cannot be achieved with standard TLR design. However, it also enables more accurate geometric optimization at low static field. Thereby, the MTMG-TLR design preserves the intrinsic advantages of TLRs, i.e. mechanical flexibility, high SAR efficiency, mass production, and coil miniaturization. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Miniature high-resolution guided-wave spectrometer for atmospheric remote sensing

NASA Astrophysics Data System (ADS)

Sloan, James; Kruzelecky, Roman; Wong, Brian; Zou, Jing; Jamroz, Wes; Haddad, Emile; Poirier, Michel

This paper describes the design and application of an innovative spectrometer in which a guided-wave integrated optical spectrometer (IOSPEC) has been coupled with a Fabry-Perot (FP) interferometer. This miniature spectrometer has a net mass under 3 kg, but is capable of broadband operation at spectral resolutions below 0.03 nm full width half maximum (FWHM). The tuneable FP filter provides very high spectral resolution combined with a large input aper-ture. The solid state guided-wave spectrometer is currently configured for a 512-channel array detector, which provides sub-nm coarse resolution. The ultimate resolution is determined by the FP filter, which is tuned across the desired spectral bands, thereby providing a signal-to-noise ratio (SNR) advantage over scanned spectrometer systems of the square root of the number of detector channels. The guided-wave optics provides robust, long-term optical alignment, while minimising the mechanical complexity. The miniaturisation of the FP-IOSPEC spectrometer allows multiple spectrometers to be accommodated on a single MicroSat. Each of these can be optimised for selected measurement tasks and views, thereby enabling more flexible data acquisition strategies with enhanced information content, while minimizing the mission cost. The application of this innovative technology in the proposed Miniature Earth Observation Satellite (MEOS) mission will also be discussed. The MEOS mission, which is designed for the investigation of the carbon and water cycles, relies on multiple IO-SPEC instruments for the simultaneous measurement of a range of atmospheric and surface properties important to climate change.

The current role of high-resolution mass spectrometry in food analysis.

PubMed

Kaufmann, Anton

2012-05-01

High-resolution mass spectrometry (HRMS), which is used for residue analysis in food, has gained wider acceptance in the last few years. This development is due to the availability of more rugged, sensitive, and selective instrumentation. The benefits provided by HRMS over classical unit-mass-resolution tandem mass spectrometry are considerable. These benefits include the collection of full-scan spectra, which provides greater insight into the composition of a sample. Consequently, the analyst has the freedom to measure compounds without previous compound-specific tuning, the possibility of retrospective data analysis, and the capability of performing structural elucidations of unknown or suspected compounds. HRMS strongly competes with classical tandem mass spectrometry in the field of quantitative multiresidue methods (e.g., pesticides and veterinary drugs). It is one of the most promising tools when moving towards nontargeted approaches. Certain hardware and software issues still have to be addressed by the instrument manufacturers for it to dislodge tandem mass spectrometry from its position as the standard trace analysis tool.

High charge-carrier mobility enables exploitation of carrier multiplication in quantum-dot films

PubMed Central

Sandeep, C. S. Suchand; Cate, Sybren ten; Schins, Juleon M.; Savenije, Tom J.; Liu, Yao; Law, Matt; Kinge, Sachin; Houtepen, Arjan J.; Siebbeles, Laurens D. A.

2013-01-01

Carrier multiplication, the generation of multiple electron–hole pairs by a single photon, is of great interest for solar cells as it may enhance their photocurrent. This process has been shown to occur efficiently in colloidal quantum dots, however, harvesting of the generated multiple charges has proved difficult. Here we show that by tuning the charge-carrier mobility in quantum-dot films, carrier multiplication can be optimized and may show an efficiency as high as in colloidal dispersion. Our results are explained quantitatively by the competition between dissociation of multiple electron–hole pairs and Auger recombination. Above a mobility of ~1 cm2 V−1 s−1, all charges escape Auger recombination and are quantitatively converted to free charges, offering the prospect of cheap quantum-dot solar cells with efficiencies in excess of the Shockley–Queisser limit. In addition, we show that the threshold energy for carrier multiplication is reduced to twice the band gap of the quantum dots. PMID:23974282

Planning Paths Through Singularities in the Center of Mass Space

NASA Technical Reports Server (NTRS)

Doggett, William R.; Messner, William C.; Juang, Jer-Nan

1998-01-01

The center of mass space is a convenient space for planning motions that minimize reaction forces at the robot's base or optimize the stability of a mechanism. A unique problem associated with path planning in the center of mass space is the potential existence of multiple center of mass images for a single Cartesian obstacle, since a single center of mass location can correspond to multiple robot joint configurations. The existence of multiple images results in a need to either maintain multiple center of mass obstacle maps or to update obstacle locations when the robot passes through a singularity, such as when it moves from an elbow-up to an elbow-down configuration. To illustrate the concepts presented in this paper, a path is planned for an example task requiring motion through multiple center of mass space maps. The object of the path planning algorithm is to locate the bang- bang acceleration profile that minimizes the robot's base reactions in the presence of a single Cartesian obstacle. To simplify the presentation, only non-redundant robots are considered and joint non-linearities are neglected.

Observing Mergers of Non-Spinning Black-Hole Binaries

NASA Technical Reports Server (NTRS)

McWilliams, Sean T.; Boggs, William D.; Baker, John G.; Kelly, Bernard J.

2010-01-01

Advances in the field of numerical relativity now make it possible to calculate the final, most powerful merger phase of binary black-hole coalescence for generic binaries. The state of the art has advanced well beyond the equal-mass case into the unequal-mass and spinning regions of parameter space. We present a study of the nonspinning portion of parameter space, primarily using an analytic waveform model tuned to available numerical data, with an emphasis on observational implications. We investigate the impact of varied m8BS ratio on merger signal-to-noise ratios (SNR) for several detectors, and compare our results with expectations from the test-mass limit. We note a striking similarity of the waveform phasing of the merger waveform across the available mass ratios. Motivated by this, we calculate the match between our equal-mass and 4:1 mass-ratio waveforms during the merger as a function of location on the source sky, using a new formalism for the match that accounts for higher harmonics. This is an indicator of the amount of degeneracy in mass ratio for mergers of moderate mass ratio systems.

Experimental demonstration of wavelength conversion between ps-pulses based on cascaded sum- and difference frequency generation (SFG+DFG) in LiNbO3 waveguides

NASA Astrophysics Data System (ADS)

Wang, Jian; Sun, Junqiang; Lou, Chuanhong; Sun, Qizhen

2005-09-01

All-optical wavelength conversion between ps-pulses based on cascaded sum- and difference frequency generation (SFG+DFG) is proposed and experimentally demonstrated in periodically poled LiNbO3 (PPLN) waveguides. The signal pulse with 40-GHz repetition rate and 1.57- ps pulse width is adopted. The converted idler wavelength can be tuned from 1527.4 to 1540.5nm as the signal wavelength is varied from 1561.9 to 1548.4nm. No obvious changes of the pulse shape and width, also no chirp are observed in the converted idler pulse. The results imply that single-to-multiple channel wavelength conversions can be achieved by appropriately tuning the two pump wavelengths.

Experimental demonstration of wavelength conversion between ps-pulses based on cascaded sum- and difference frequency generation (SFG+DFG) in LiNbO3 waveguides.

PubMed

Wang, Jian; Sun, Junqiang; Lou, Chuanhong; Sun, Qizhen

2005-09-19

All-optical wavelength conversion between ps-pulses based on cascaded sum- and difference frequency generation (SFG+DFG) is proposed and experimentally demonstrated in periodically poled LiNbO3 (PPLN) waveguides. The signal pulse with 40-GHz repetition rate and 1.57- ps pulse width is adopted. The converted idler wavelength can be tuned from 1527.4 to 1540.5nm as the signal wavelength is varied from 1561.9 to 1548.4nm. No obvious changes of the pulse shape and width, also no chirp are observed in the converted idler pulse. The results imply that single-to-multiple channel wavelength conversions can be achieved by appropriately tuning the two pump wavelengths.

Correlated neuronal discharges that increase coding efficiency during perceptual discrimination.

PubMed

Romo, Ranulfo; Hernández, Adrián; Zainos, Antonio; Salinas, Emilio

2003-05-22

During a sensory discrimination task, the responses of multiple sensory neurons must be combined to generate a choice. The optimal combination of responses is determined both by their dependence on the sensory stimulus and by their cofluctuations across trials-that is, the noise correlations. Positively correlated noise is considered deleterious, because it limits the coding accuracy of populations of similarly tuned neurons. However, positively correlated fluctuations between differently tuned neurons actually increase coding accuracy, because they allow the common noise to be subtracted without signal loss. This is demonstrated with data recorded from the secondary somatosensory cortex of monkeys performing a vibrotactile discrimination task. The results indicate that positive correlations are not always harmful and may be exploited by cortical networks to enhance the neural representation of features to be discriminated.

Tuning the group delay of optical wave packets in liquid-crystal light valves

NASA Astrophysics Data System (ADS)

Bortolozzo, U.; Residori, S.; Huignard, J. P.

2009-05-01

By performing two-wave mixing experiments in a liquid-crystal light valve, optical pulses are slowed down to group velocities as slow as a few tenths of mm/s, corresponding to a very large group index. We present experiments and model of the slow-light process occurring in the liquid-crystal light valve, showing that this is characterized by multiple-beam diffraction in the Raman-Nath regime. Depending on the initial frequency detuning between pump and signal, the different output order beams are distinguished by different group delays. The group delay can be tuned by changing the main parameters of the experiment: the detuning between the pump and the input wave packet, the strength of the nonlinearity, and the intensity of the pump beam.

Multiple shell fusion targets

DOEpatents

Lindl, J.D.; Bangerter, R.O.

1975-10-31

Multiple shell fusion targets for use with electron beam and ion beam implosion systems are described. The multiple shell targets are of the low-power type and use a separate relatively low Z, low density ablator at large radius for the outer shell, which reduces the focusing and power requirements of the implosion system while maintaining reasonable aspect ratios. The targets use a high Z, high density pusher shell placed at a much smaller radius in order to obtain an aspect ratio small enough to protect against fluid instability. Velocity multiplication between these shells further lowers the power requirements. Careful tuning of the power profile and intershell density results in a low entropy implosion which allows breakeven at low powers. For example, with ion beams as a power source, breakeven at 10-20 Terrawatts with 10 MeV alpha particles for imploding a multiple shell target can be accomplished.

Load reduction of a monopile wind turbine tower using optimal tuned mass dampers

NASA Astrophysics Data System (ADS)

Tong, Xin; Zhao, Xiaowei; Zhao, Shi

2017-07-01

We investigate to apply tuned mass dampers (TMDs) (one in the fore-aft direction, one in the side-side direction) to suppress the vibration of a monopile wind turbine tower. Using the spectral element method, we derive a finite-dimensional state-space model Σd from an infinite-dimensional model Σ of a monopile wind turbine tower stabilised by a TMD located in the nacelle. Σ and Σd can be used to represent the dynamics of the tower and TMD in either the fore-aft direction or the side-side direction. The wind turbine tower subsystem of Σ is modelled as a non-uniform SCOLE (NASA Spacecraft Control Laboratory Experiment) system consisting of an Euler-Bernoulli beam equation describing the dynamics of the flexible tower and the Newton-Euler rigid body equations describing the dynamics of the heavy rotor-nacelle assembly (RNA) by neglecting any coupling with blade motions. Σd can be used for fast and accurate simulation for the dynamics of the wind turbine tower as well as for optimal TMD designs. We show that Σd agrees very well with the FAST (fatigue, aerodynamics, structures and turbulence) simulation of the NREL 5-MW wind turbine model. We optimise the parameters of the TMD by minimising the frequency-limited ?-norm of the transfer function matrix of Σd which has input of force and torque acting on the RNA, and output of tower-top displacement. The performances of the optimal TMDs in the fore-aft and side-side directions are tested through FAST simulations, which achieve substantial fatigue load reductions. This research also demonstrates how to optimally tune TMDs to reduce vibrations of flexible structures described by partial differential equations.

Dynamically avoiding fine-tuning the cosmological constant: the ``Relaxed Universe''

NASA Astrophysics Data System (ADS)

Bauer, Florian; Solà, Joan; Štefancić, Hrvoje

2010-12-01

We demonstrate that there exists a large class of Script F(R,Script G) action functionals of the scalar curvature and of the Gauß-Bonnet invariant which are able to relax dynamically a large cosmological constant (CC), whatever it be its starting value in the early universe. Hence, it is possible to understand, without fine-tuning, the very small current value Λ0 ~ H02 of the CC as compared to its theoretically expected large value in quantum field theory and string theory. In our framework, this relaxation appears as a pure gravitational effect, where no ad hoc scalar fields are needed. The action involves a positive power of a characteristic mass parameter, Script M, whose value can be, interestingly enough, of the order of a typical particle physics mass of the Standard Model of the strong and electroweak interactions or extensions thereof, including the neutrino mass. The model universe emerging from this scenario (the ``Relaxed Universe'') falls within the class of the so-called ΛXCDM models of the cosmic evolution. Therefore, there is a ``cosmon'' entity X (represented by an effective object, not a field), which in this case is generated by the effective functional Script F(R,Script G) and is responsible for the dynamical adjustment of the cosmological constant. This model universe successfully mimics the essential past epochs of the standard (or ``concordance'') cosmological model (ΛCDM). Furthermore, it provides interesting clues to the coincidence problem and it may even connect naturally with primordial inflation.

Method of making an InAsSb/InAsSbP diode lasers

DOEpatents

Razeghi, M.

1997-08-19

InAsSb/InAsSbP/InAs Double Heterostructures (DH) and Separate Confinement Heterostructure Multiple Quantum Well (SCH-MQW) structures are taught wherein the ability to tune to a specific wavelength within 3 {micro}m to 5 {micro}m is possible by varying the ratio of As:Sb in the active layer. 9 figs.

MALDI imaging mass spectrometry analysis-A new approach for protein mapping in multiple sclerosis brain lesions.

PubMed

Maccarrone, Giuseppina; Nischwitz, Sandra; Deininger, Sören-Oliver; Hornung, Joachim; König, Fatima Barbara; Stadelmann, Christine; Turck, Christoph W; Weber, Frank

2017-03-15

Multiple sclerosis is a disease of the central nervous system characterized by recurrent inflammatory demyelinating lesions in the early disease stage. Lesion formation and mechanisms leading to lesion remyelination are not fully understood. Matrix Assisted Laser Desorption Ionisation Mass Spectrometry imaging (MALDI-IMS) is a technology which analyses proteins and peptides in tissue, preserves their spatial localization, and generates molecular maps within the tissue section. In a pilot study we employed MALDI imaging mass spectrometry to profile and identify peptides and proteins expressed in normal-appearing white matter, grey matter and multiple sclerosis brain lesions with different extents of remyelination. The unsupervised clustering analysis of the mass spectra generated images which reflected the tissue section morphology in luxol fast blue stain and in myelin basic protein immunohistochemistry. Lesions with low remyelination extent were defined by compounds with molecular weight smaller than 5300Da, while more completely remyelinated lesions showed compounds with molecular weights greater than 15,200Da. An in-depth analysis of the mass spectra enabled the detection of cortical lesions which were not seen by routine luxol fast blue histology. An ion mass, mainly distributed at the rim of multiple sclerosis lesions, was identified by liquid chromatography and tandem mass spectrometry as thymosin beta-4, a protein known to be involved in cell migration and in restorative processes. The ion mass of thymosin beta-4 was profiled by MALDI imaging mass spectrometry in brain slides of 12 multiple sclerosis patients and validated by immunohistochemical analysis. In summary, our results demonstrate the ability of the MALDI-IMS technology to map proteins within the brain parenchyma and multiple sclerosis lesions and to identify potential markers involved in multiple sclerosis pathogenesis and/or remyelination. Copyright © 2016 Elsevier B.V. All rights reserved.

Geometric interpretations for resonances of plasmonic nanoparticles

NASA Astrophysics Data System (ADS)

Liu, Wei; Oulton, Rupert F.; Kivshar, Yuri S.

2015-07-01

The field of plasmonics can be roughly categorized into two branches: surface plasmon polaritons (SPPs) propagating in waveguides and localized surface plasmons (LSPs) supported by scattering particles. Investigations along these two directions usually employ different approaches, resulting in more or less a dogma that the two branches progress almost independently of each other, with few interactions. Here in this work we interpret LSPs from a Bohr model based geometric perspective relying on SPPs, thus establishing a connection between these two sub-fields. Besides the clear explanations of conventional scattering features of plasmonic nanoparticles, based on this geometric model we further demonstrate other anomalous scattering features (higher order modes supported at lower frequencies, and blueshift of the resonance with increasing particle sizes) and multiple electric resonances of the same order supported at different frequencies, which have been revealed to originate from backward SPP modes and multiple dispersion bands supported in the corresponding plasmonic waveguides, respectively. Inspired by this geometric model, it is also shown that, through solely geometric tuning, the absorption of each LSP resonance can be maximized to reach the single channel absorption limit, provided that the scattering and absorption rates are tuned to be equal.

Polarization manipulation in single refractive prism based holography lithography

NASA Astrophysics Data System (ADS)

Xiong, Wenjie; Xu, Yi; Xiao, Yujian; Lv, Xiaoxu; Wu, Lijun

2015-01-01

We propose theoretically and demonstrate experimentally a simple but effective strategy for polarization manipulation in single refractive prism based holographic lithography. By tuning the polarization of a single laser beam, we can obtain the pill shape interference pattern with a high-contrast where a complex optical setup and multiple polarizers are needed in the conventional holography lithography. Fabrication of pill shape two-dimensional polymer photonic crystals using one beam and one shoot holography lithography is shown as an example to support our theoretical results. This integrated polarization manipulation technique can release the crucial stability restrictions imposed on the multiple beams holography lithography.

Three Dimensional Imaging with Multiple Wavelength Speckle Interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernacki, Bruce E.; Cannon, Bret D.; Schiffern, John T.

2014-05-28

We present the design, modeling, construction, and results of a three-dimensional imager based upon multiple-wavelength speckle interferometry. A surface under test is illuminated with tunable laser light in a Michelson interferometer configuration while a speckled image is acquired at each laser frequency step. The resulting hypercube is Fourier transformed in the frequency dimension and the beat frequencies that result map the relative offsets of surface features. Synthetic wavelengths resulting from the laser tuning can probe features ranging from 18 microns to hundreds of millimeters. Three dimensional images will be presented along with modeling results.

Implementation and Evaluation of Multiple Adaptive Control Technologies for a Generic Transport Aircraft Simulation

NASA Technical Reports Server (NTRS)

Campbell, Stefan F.; Kaneshige, John T.; Nguyen, Nhan T.; Krishakumar, Kalmanje S.

2010-01-01

Presented here is the evaluation of multiple adaptive control technologies for a generic transport aircraft simulation. For this study, seven model reference adaptive control (MRAC) based technologies were considered. Each technology was integrated into an identical dynamic-inversion control architecture and tuned using a methodology based on metrics and specific design requirements. Simulation tests were then performed to evaluate each technology s sensitivity to time-delay, flight condition, model uncertainty, and artificially induced cross-coupling. The resulting robustness and performance characteristics were used to identify potential strengths, weaknesses, and integration challenges of the individual adaptive control technologies

A facile single-step synthesis of ternary multicore magneto-plasmonic nanoparticles.

PubMed

Benelmekki, Maria; Bohra, Murtaza; Kim, Jeong-Hwan; Diaz, Rosa E; Vernieres, Jerome; Grammatikopoulos, Panagiotis; Sowwan, Mukhles

2014-04-07

We report a facile single-step synthesis of ternary hybrid nanoparticles (NPs) composed of multiple dumbbell-like iron-silver (FeAg) cores encapsulated by a silicon (Si) shell using a versatile co-sputter gas-condensation technique. In comparison to previously reported binary magneto-plasmonic NPs, the advantage conferred by a Si shell is to bind the multiple magneto-plasmonic (FeAg) cores together and prevent them from aggregation at the same time. Further, we demonstrate that the size of the NPs and number of cores in each NP can be modulated over a wide range by tuning the experimental parameters.

Magnetically controlled multifrequency invisibility cloak with a single shell of ferrite material

NASA Astrophysics Data System (ADS)

Wang, Xiaohua; Liu, Youwen

2015-02-01

A magnetically controlled multifrequency invisibility cloak with a single shell of the isotropic and homogeneous ferrite material has been investigated based on the scattering cancellation method from the Mie scattering theory. The analytical and simulated results have demonstrated that such this shell can drastically reduce the total scattering cross-section of this cloaking system at multiple frequencies. These multiple cloaking frequencies of this shell can be externally controlled since the magnetic permeability of ferrites is well tuned by the applied magnetic field. This may provide a potential way to design a tunable multifrequency invisibility cloak with considerable flexibility.

An International Symposium and Exhibition on Active Materials and Adaptive Structures.

DTIC Science & Technology

1991-11-08

into Tubular Composite Structures Using Embedded Constraining Layers 232 S. Sattinger, Z. Sanjana, Westinghouse Science and Technology Center...struts, constrained layers , and tuned mass dampers. The most effective damping treatment was selected for each mode depending on its modal...paper) the passive damping component* in the structure will be deserth^ These »dude constrained layer viscoelastic struts« viscous DStrlJi . .^ of

Moduli stabilization in stringy ISS models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakayama, Yu; Nakayama, Yu; Yamazaki, Masahito

2007-09-28

We present a stringy realization of the ISS metastable SUSY breaking model with moduli stabilization. The mass moduli of the ISS model is stabilized by gauging of a U(1) symmetry and its D-term potential. The SUSY is broken both by F-terms and D-terms. It is possible to obtain de Sitter vacua with a vanishingly small cosmological constant by an appropriate fine-tuning of flux parameters.

Ion related problems for the XLS ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bozoki, E.; Halama, H.

1989-07-11

The electron beam in the XLS will collide with the residual gas in the vacuum chamber. The positive ions will be trapped in the potential well of the electron beam. They will perform stable or unstable oscillations around the beam under the repetitive Coulomb force of the bunches. If not cleared, the captured ions will lead to partial or total neutralization of the beam, causing both, a decrease of life-time and a change in the vertical tunes as well as an increase in the tune-spread. They can also cause coherent transverse instabilities. The degree of neutralization {theta} that one canmore » tolerate, is primarily determined by the allowable tune shift, which of the XLS is between 1 and 5 10{sup {minus}3}. Electrostatic clearing electrodes will be used to keep the neutralization below the desired limit. In order to determine their location and the necessary clearing-rate and voltage, we examine the ion production rate, longitudinal velocity of ions in field-free regions and in the dipoles to see what distance the ions can travel without clearing before the neutralization of the beam reaches the prescribed limit, beam potential to see the locations of the potential wells, voltage requirements for ion clearing, critical mass for ion capture in the bunched beam, tune shift caused by neutralization of the beam, pressure rise due to the trapped ions and power dissipation due to beam image current. 13 refs., 3 figs., 4 tabs.« less

Naturalness of MSSM dark matter

NASA Astrophysics Data System (ADS)

Cabrera, María Eugenia; Casas, J. Alberto; Delgado, Antonio; Robles, Sandra; de Austri, Roberto Ruiz

2016-08-01

There exists a vast literature examining the electroweak (EW) fine-tuning problem in supersymmetric scenarios, but little concerned with the dark matter (DM) one, which should be combined with the former. In this paper, we study this problem in an, as much as possible, exhaustive and rigorous way. We have considered the MSSM framework, assuming that the LSP is the lightest neutralino, χ 1 0 , and exploring the various possibilities for the mass and composition of χ 1 0 , as well as different mechanisms for annihilation of the DM particles in the early Universe (well-tempered neutralinos, funnels and co-annihilation scenarios). We also present a discussion about the statistical meaning of the fine-tuning and how it should be computed for the DM abundance, and combined with the EW fine-tuning. The results are very robust and model-independent and favour some scenarios (like the h-funnel when {M}_{χ_1^0} is not too close to m h /2) with respect to others (such as the pure wino case). These features should be taken into account when one explores "natural SUSY" scenarios and their possible signatures at the LHC and in DM detection experiments.

Integrative Analysis of “-Omics” Data Using Penalty Functions

PubMed Central

Zhao, Qing; Shi, Xingjie; Huang, Jian; Liu, Jin; Li, Yang; Ma, Shuangge

2014-01-01

In the analysis of omics data, integrative analysis provides an effective way of pooling information across multiple datasets or multiple correlated responses, and can be more effective than single-dataset (response) analysis. Multiple families of integrative analysis methods have been proposed in the literature. The current review focuses on the penalization methods. Special attention is paid to sparse meta-analysis methods that pool summary statistics across datasets, and integrative analysis methods that pool raw data across datasets. We discuss their formulation and rationale. Beyond “standard” penalized selection, we also review contrasted penalization and Laplacian penalization which accommodate finer data structures. The computational aspects, including computational algorithms and tuning parameter selection, are examined. This review concludes with possible limitations and extensions. PMID:25691921

Toroid cavity/coil NMR multi-detector

DOEpatents

Gerald, II, Rex E.; Meadows, Alexander D.; Gregar, Joseph S.; Rathke, Jerome W.

2007-09-18

An analytical device for rapid, non-invasive nuclear magnetic resonance (NMR) spectroscopy of multiple samples using a single spectrometer is provided. A modified toroid cavity/coil detector (TCD), and methods for conducting the simultaneous acquisition of NMR data for multiple samples including a protocol for testing NMR multi-detectors are provided. One embodiment includes a plurality of LC resonant circuits including spatially separated toroid coil inductors, each toroid coil inductor enveloping its corresponding sample volume, and tuned to resonate at a predefined frequency using a variable capacitor. The toroid coil is formed into a loop, where both ends of the toroid coil are brought into coincidence. Another embodiment includes multiple micro Helmholtz coils arranged on a circular perimeter concentric with a central conductor of the toroid cavity.

Quasiperiodic one-dimensional photonic crystals with adjustable multiple photonic bandgaps.

PubMed

Vyunishev, Andrey M; Pankin, Pavel S; Svyakhovskiy, Sergey E; Timofeev, Ivan V; Vetrov, Stepan Ya

2017-09-15

We propose an elegant approach to produce photonic bandgap (PBG) structures with multiple photonic bandgaps by constructing quasiperiodic photonic crystals (QPPCs) composed of a superposition of photonic lattices with different periods. Generally, QPPC structures exhibit both aperiodicity and multiple PBGs due to their long-range order. They are described by a simple analytical expression, instead of quasiperiodic tiling approaches based on substitution rules. Here we describe the optical properties of QPPCs exhibiting two PBGs that can be tuned independently. PBG interband spacing and its depth can be varied by choosing appropriate reciprocal lattice vectors and their amplitudes. These effects are confirmed by the proof-of-concept measurements made for the porous silicon-based QPPC of the appropriate design.

Trion-Polariton Formation in Single-Walled Carbon Nanotube Microcavities

PubMed Central

2018-01-01

We demonstrate the formation and tuning of charged trion-polaritons in polymer-sorted (6,5) single-walled carbon nanotubes in a planar metal-clad microcavity at room temperature. The positively charged trion-polaritons were induced by electrochemical doping and characterized by angle-resolved reflectance and photoluminescence spectroscopy. The doping level of the nanotubes within the microcavity was controlled by the applied bias and thus enabled tuning from mainly excitonic to a mixture of exciton and trion transitions. Mode splitting of more than 70 meV around the trion energy and emission from the new lower polariton branch corroborate a transition from exciton-polaritons (neutral) to trion-polaritons (charged). The estimated charge-to-mass ratio of these trion-polaritons is 200 times higher than that of electrons or holes in carbon nanotubes, which has exciting implications for the realization of polaritonic charge transport.

Tuning structure of oppositely charged nanoparticle and protein complexes

NASA Astrophysics Data System (ADS)

Kumar, Sugam; Aswal, V. K.; Callow, P.

2014-04-01

Small-angle neutron scattering (SANS) has been used to probe the structures of anionic silica nanoparticles (LS30) and cationic lyszyme protein (M.W. 14.7kD, I.P. ˜ 11.4) by tuning their interaction through the pH variation. The protein adsorption on nanoparticles is found to be increasing with pH and determined by the electrostatic attraction between two components as well as repulsion between protein molecules. We show the strong electrostatic attraction between nanoparticles and protein molecules leads to protein-mediated aggregation of nanoparticles which are characterized by fractal structures. At pH 5, the protein adsorption gives rise to nanoparticle aggregation having surface fractal morphology with close packing of nanoparticles. The surface fractals transform to open structures of mass fractal morphology at higher pH (7 and 9) on approaching isoelectric point (I.P.).

Macroscopic Entangled State Generation with Optomechanical Coupling of Two Mechanical Modes

NASA Astrophysics Data System (ADS)

Weaver, Matthew; Luna, Fernando; Buters, Frank; Heeck, Kier; de Man, Sven; Bouwmeester, Dirk

Mechanical resonators with a large quantum position uncertainty are an excellent test system for proposed decoherence mechanisms in massive systems. We present a scheme to optomechanically entangle two mechanical resonators with large frequency separation via two tone driving and single photon projection measurements. The quantum position uncertainty can be tuned with a variable optical pulse displacement operation, and independent single photon readout of the two resonators provides robust verification of the quantum states of the system. This scheme is currently experimentally feasible in a number of high mass opto- and electro-mechanical systems. We demonstrate one such system with two spatially and frequency separated Si3N4 trampoline resonators. We also show how the resonators can be coupled with two tone driving and the single photon optomechanical coupling rates can be tuned.

Evaluation and benchmarking of an EC-QCL-based mid-infrared spectrometer for monitoring metabolic blood parameters in critical care units

NASA Astrophysics Data System (ADS)

Grafen, M.; Delbeck, S.; Busch, H.; Heise, H. M.; Ostendorf, A.

2018-02-01

Mid-infrared spectroscopy hyphenated with micro-dialysis is an excellent method for monitoring metabolic blood parameters as it enables the concurrent, reagent-free and precise measurement of multiple clinically relevant substances such as glucose, lactate and urea in micro-dialysates of blood or interstitial fluid. For a marketable implementation, quantum cascade lasers (QCL) seem to represent a favourable technology due to their high degree of miniaturization and potentially low production costs. In this work, an external cavity (EC) - QCL-based spectrometer and two Fourier-transform infrared (FTIR) spectrometers were benchmarked with regard to the precision, accuracy and long-term stability needed for the monitoring of critically ill patients. For the tests, ternary aqueous solutions of glucose, lactate and mannitol (the latter for dialysis recovery determination) were measured in custom-made flow-through transmission cells of different pathlengths and analyzed by Partial Least Squares calibration models. It was revealed, that the wavenumber tuning speed of the QCL had a severe impact on the EC-mirror trajectory due to matching the digital-analog-converter step frequency with the mechanical resonance frequency of the mirror actuation. By selecting an appropriate tuning speed, the mirror oscillations acted as a hardware smoothing filter for the significant intensity variations caused by mode hopping. Besides the tuning speed, the effects of averaging over multiple spectra and software smoothing parameters (Savitzky-Golay-filters and FT-smoothing) were investigated. The final settings led to a performance of the QCL-system, which was comparable with a research FTIR-spectrometer and even surpassed the performance of a small FTIR-mini-spectrometer.

Spatial and Feature-Based Attention in a Layered Cortical Microcircuit Model

PubMed Central

Wagatsuma, Nobuhiko; Potjans, Tobias C.; Diesmann, Markus; Sakai, Ko; Fukai, Tomoki

2013-01-01

Directing attention to the spatial location or the distinguishing feature of a visual object modulates neuronal responses in the visual cortex and the stimulus discriminability of subjects. However, the spatial and feature-based modes of attention differently influence visual processing by changing the tuning properties of neurons. Intriguingly, neurons' tuning curves are modulated similarly across different visual areas under both these modes of attention. Here, we explored the mechanism underlying the effects of these two modes of visual attention on the orientation selectivity of visual cortical neurons. To do this, we developed a layered microcircuit model. This model describes multiple orientation-specific microcircuits sharing their receptive fields and consisting of layers 2/3, 4, 5, and 6. These microcircuits represent a functional grouping of cortical neurons and mutually interact via lateral inhibition and excitatory connections between groups with similar selectivity. The individual microcircuits receive bottom-up visual stimuli and top-down attention in different layers. A crucial assumption of the model is that feature-based attention activates orientation-specific microcircuits for the relevant feature selectively, whereas spatial attention activates all microcircuits homogeneously, irrespective of their orientation selectivity. Consequently, our model simultaneously accounts for the multiplicative scaling of neuronal responses in spatial attention and the additive modulations of orientation tuning curves in feature-based attention, which have been observed widely in various visual cortical areas. Simulations of the model predict contrasting differences between excitatory and inhibitory neurons in the two modes of attentional modulations. Furthermore, the model replicates the modulation of the psychophysical discriminability of visual stimuli in the presence of external noise. Our layered model with a biologically suggested laminar structure describes the basic circuit mechanism underlying the attention-mode specific modulations of neuronal responses and visual perception. PMID:24324628

Naturalizing supersymmetry with a two-field relaxion mechanism

DOE PAGES

Evans, Jason L.; Gherghetta, Tony; Nagata, Natsumi; ...

2016-09-26

We present a supersymmetric version of a two-field relaxion model that naturalizes tuned versions of supersymmetry. This arises from a relaxion mechanism that does not depend on QCD dynamics and where the relaxion potential barrier height is controlled by a second axion-like field. During the cosmological evolution, the relaxion rolls with a nonzero value that breaks supersymmetry and scans the soft supersymmetric mass terms. Electroweak symmetry is broken after the soft masses become of order the supersymmetric Higgs mass term and causes the relaxion to stop rolling for superpartner masses up to ~10 9 GeV. This can explain the tuningmore » in supersymmetric models, including split-SUSY models, while preserving the QCD axion solution to the strong CP problem. Furthermore, besides predicting two very weakly-coupled axion-like particles, the supersymmetric spectrum may contain an extra Goldstino, which could be a viable dark matter candidate.« less

Increase in transmission loss of a double panel system by addition of mass inclusions to a poro-elastic layer: A comparison between theory and experiment

NASA Astrophysics Data System (ADS)

Idrisi, Kamal; Johnson, Marty E.; Toso, Alessandro; Carneal, James P.

2009-06-01

This paper is concerned with the modeling and optimization of heterogeneous (HG) blankets, which are used in this investigation to reduce the sound transmission through double panel systems. HG blankets consist of poro-elastic media with small embedded masses, which act similarly to a distributed mass-spring-damper-system. HG blankets have shown significant potential to reduce low frequency radiated sound from structures, where traditional poro-elastic materials have little effect. A mathematical model of a double panel system with an acoustic cavity and HG blanket was developed using impedance and mobility methods. The predicted responses of the source and the receiving panel due to a point force are validated with experimental measurements. The presented results indicate that proper tuning of the HG blankets can result in broadband noise reduction below 500 Hz with less than 10% added mass.

Users manual for program NYQUIST: Liquid rocket nyquist plots developed for use on a PC computer

NASA Astrophysics Data System (ADS)

Armstrong, Wilbur C.

1992-06-01

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the NYQUIST code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, and the splitting of a pipe into unequal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines. The code is too large to compile as one program using Microsoft FORTRAN 5; therefore, the code was broken into two segments: NYQUIST1.FOR and NYQUIST2.FOR. These are compiled separately and then linked together. The final run code is not too large (approximately equals 344,000 bytes).

Users manual for program NYQUIST: Liquid rocket nyquist plots developed for use on a PC computer

NASA Technical Reports Server (NTRS)

Armstrong, Wilbur C.

1992-01-01

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the NYQUIST code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, and the splitting of a pipe into unequal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines. The code is too large to compile as one program using Microsoft FORTRAN 5; therefore, the code was broken into two segments: NYQUIST1.FOR and NYQUIST2.FOR. These are compiled separately and then linked together. The final run code is not too large (approximately equals 344,000 bytes).

Supernatural supersymmetry and its classic example: M-theory inspired NMSSM

NASA Astrophysics Data System (ADS)

Li, Tianjun; Raza, Shabbar; Wang, Xiao-Chuan

2016-06-01

We briefly review the supernatural supersymmetry (SUSY), which provides a most promising solution to the SUSY electroweak fine-tuning problem. In particular, we address its subtle issues as well. Unlike the minimal supersymmetric standard model (MSSM), the next to MSSM (NMSSM) can be scale invariant and has no mass parameter in its Lagrangian before SUSY and gauge symmetry breakings. Therefore, the NMSSM is a perfect framework for supernatural SUSY. To give the SUSY breaking soft mass to the singlet, we consider the moduli and dilaton dominant SUSY breaking scenarios in M-theory on S1/Z2. In these scenarios, SUSY is broken by one and only one F term of moduli or dilaton, and the SUSY breaking soft terms can be determined via the Kähler potential and superpotential from Calabi-Yau compactification of M-theory on S1/Z2. Thus, as predicted by supernatural SUSY, the SUSY electroweak fine-tuning measure is of unity order. In the moduli dominant SUSY breaking scenario, the right-handed sleptons are relatively light around 1 TeV, stau can even be as light as 580 GeV and degenerate with the lightest neutralino, chargino masses are larger than 1 TeV, the light stop masses are around 2 TeV or larger, the first two-generation squark masses are about 3 TeV or larger, and gluinos are heavier tha.n squarks. In the dilaton dominant SUSY breaking scenario, the qualitative picture remains the same but we have heavier spectra as compared to the moduli dominant SUSY breaking scenario. In addition to it, we have Higgs H2/A1-resonance solutions for dark matter (DM). In both scenarios, the minimal value of DM relic density is about 0.2. To obtain the observed DM relic density, we can consider the dilution effect from supercritical string cosmology or introduce the axino as the lightest supersymmetric particle.

40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Determination of NOX mass emissions... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING NOX Mass Emissions Provisions § 75.72 Determination of NOX mass emissions for common stack and multiple stack...

Correlations of neutron multiplicity and γ -ray multiplicity with fragment mass and total kinetic energy in spontaneous fission of Cf 252

DOE PAGES

Wang, Taofeng; Li, Guangwu; Zhu, Liping; ...

2016-01-08

The dependence of correlations of neutron multiplicity ν and γ-ray multiplicity M γ in spontaneous fission of 252Cf on fragment mass A* and total kinetic energy (TKE) have been investigated by employing the ratio of M γ/ν and the form of M γ(ν). We show for the first time that M γ and ν have a complex correlation for heavy fragment masses, while there is a positive dependence of Mγ for light fragment masses and for near-symmetric mass splits. The ratio M γ/ν exhibits strong shell effects for neutron magic number N=50 and near doubly magic number shell closure atmore » Z=50 and N=82. The γ-ray multiplicity Mγ has a maximum for TKE=165-170 MeV. Above 170 MeV M γ(TKE) is approximately linear, while it deviates significantly from a linear dependence at lower TKE. The correlation between the average neutron and γ-ray multiplicities can be partly reproduced by model calculations.« less

Lightweight acoustic treatments for aerospace applications

NASA Astrophysics Data System (ADS)

Naify, Christina Jeanne

2011-12-01

Increase in the use of composites for aerospace applications has the benefit of decreased structural weight, but at the cost of decreased acoustic performance. Stiff, lightweight structures (such as composites) are traditionally not ideal for acoustic insulation applications because of high transmission loss at low frequencies. A need has thus arisen for effective sound insulation materials for aerospace and automotive applications with low weight addition. Current approaches, such as the addition of mass law dominated materials (foams) also perform poorly when scaled to small thickness and low density. In this dissertation, methods which reduce sound transmission without adding significant weight are investigated. The methods presented are intended to be integrated into currently used lightweight structures such as honeycomb sandwich panels and to cover a wide range of frequencies. Layering gasses of differing acoustic impedances on a panel substantially reduced the amount of sound energy transmitted through the panel with respect to the panel alone or an equivalent-thickness single species gas layer. The additional transmission loss derives from successive impedance mismatches at the interfaces between gas layers and the resulting inefficient energy transfer. Attachment of additional gas layers increased the transmission loss (TL) by as much as 17 dB at high (>1 kHz) frequencies. The location and ordering of the gasses with respect to the panel were important factors in determining the magnitude of the total TL. Theoretical analysis using a transfer matrix method was used to calculate the frequency dependence of sound transmission for the different configurations tested. The method accurately predicted the relative increases in TL observed with the addition of different gas layer configurations. To address low-frequency sound insulation, membrane-type locally resonant acoustic materials (LRAM) were fabricated, characterized, and analyzed to understand their acoustic response. Acoustic metamaterials with negative dynamic mass density have been shown to demonstrate a significant (5x) increase in TL over mass law predictions for a narrow band (100Hz) at low frequencies (100--1000Hz). The peak TL frequency can be tuned to specific values by varying the membrane and mass properties. TL magnitude as a function of frequency was measured for variations of the mass magnitude and membrane tension using an impedance tube setup. The dynamic properties of membranes constructed from different materials and thicknesses were measured and compared to the results of coupled field acoustic-structural finite element analysis (FEA) modeling to understand the role of tension and element quality factor. To better comprehend the mechanism(s) responsible for the TL peak, a laser vibrometer was used to map the out-of-plane dynamic response of the structure under acoustic loading at discrete frequencies. Negative dynamic mass was experimentally demonstrated at the peak TL frequency. The scale-up of the acoustic metamaterial structure was explored by examining the behavior of multiple elements arranged in arrays. Single membranes were stretched over rigid frame supports and masses were attached to the center of each divided cell. TL behavior was measured for multiple configurations with different magnitudes of mass distributed across each of the cell membranes in the array resulting in a multi-peak TL profile. To better understand scale-up issues, the effect of the frame structure compliance was evaluated, and more compliant frames resulted in a reduction in TL peak frequency bandwidth. In addition, displacement measurements of frames and membranes were performed using a laser vibrometer. The measured TL of the multi-celled structure was compared with TL behavior predicted by FEA to understand the role of non-uniform mass distribution and frame compliance. TL of membrane-type LRAM with added ring masses was analyzed using both finite element analysis and experimental techniques. The addition of a ring mass to the structure either increased the bandwidth of the TL peak, or introduced multiple peaks, depending on the number of rings, the distribution of mass between the center and ring masses, and radii of the rings. FEA was used to predict TL behavior of several ring configurations, and TL for these configurations was measured to validate the model predictions. Finally, FEA was used to predict the mode shapes of the structure under single-frequency excitation to understand the mechanisms responsible for the TL peaks.

Improving naturalness in warped models with a heavy bulk Higgs boson

NASA Astrophysics Data System (ADS)

Cabrer, Joan A.; von Gersdorff, Gero; Quirós, Mariano

2011-08-01

A standard-model-like Higgs boson should be light in order to comply with electroweak precision measurements from LEP. We consider five-dimensional warped models—with a deformation of the metric in the IR region—as UV completions of the standard model with a heavy Higgs boson. Provided the Higgs boson propagates in the five-dimensional bulk the Kaluza Klein (KK) modes of the gauge bosons can compensate for the Higgs boson contribution to oblique parameters while their masses lie within the range of the LHC. The little hierarchy between KK scale and Higgs mass essentially disappears and the naturalness of the model greatly improves with respect to the Anti-de Sitter (Randall-Sundrum) model. In fact the fine-tuning is better than 10% for all values of the Higgs boson mass.

Thermal rectification in mass-graded next-nearest-neighbor Fermi-Pasta-Ulam lattices

NASA Astrophysics Data System (ADS)

Romero-Bastida, M.; Miranda-Peña, Jorge-Orlando; López, Juan M.

2017-03-01

We study the thermal rectification efficiency, i.e., quantification of asymmetric heat flow, of a one-dimensional mass-graded anharmonic oscillator Fermi-Pasta-Ulam lattice both with nearest-neighbor (NN) and next-nearest-neighbor (NNN) interactions. The system presents a maximum rectification efficiency for a very precise value of the parameter that controls the coupling strength of the NNN interactions, which also optimizes the rectification figure when its dependence on mass asymmetry and temperature differences is considered. The origin of the enhanced rectification is the asymmetric local heat flow response as the heat reservoirs are swapped when a finely tuned NNN contribution is taken into account. A simple theoretical analysis gives an estimate of the optimal NNN coupling in excellent agreement with our simulation results.

Reconstruction of mass balance variations for Franz Josef Glacier, New Zealand, 1913 to 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woo, Mingko Woo; Fitzharris, B.B.

1992-11-01

A model of mass balance is constructed for the Franz Josef Glacier on the west coast of New Zealand. It uses daily data from a nearby, but short-record climate station. The model is extended back to 1913 by creating hybrid climate data from a long-record, but more distant, climate station. Its monthly data provide long-term temperature and precipitation trends, and daily fluctuations are simulated using a stochastic approach that is tuned to the characteristics of the short-record station. The glacier model provides estimates of equilibrium-line altitudes which are in reasonable agreement with those observed, and variations of cumulative mass balancemore » that correspond with patterns of advance and retreat of the glacier terminus.« less

Two-dimensional N = 2 Super-Yang-Mills Theory

NASA Astrophysics Data System (ADS)

August, Daniel; Wellegehausen, Björn; Wipf, Andreas

2018-03-01

Supersymmetry is one of the possible scenarios for physics beyond the standard model. The building blocks of this scenario are supersymmetric gauge theories. In our work we study the N = 1 Super-Yang-Mills (SYM) theory with gauge group SU(2) dimensionally reduced to two-dimensional N = 2 SYM theory. In our lattice formulation we break supersymmetry and chiral symmetry explicitly while preserving R symmetry. By fine tuning the bar-mass of the fermions in the Lagrangian we construct a supersymmetric continuum theory. To this aim we carefully investigate mass spectra and Ward identities, which both show a clear signal of supersymmetry restoration in the continuum limit.

A Modified Alderman-Grant Coil makes possible an efficient cross-coil probe for high field solid-state NMR of lossy biological samples

NASA Astrophysics Data System (ADS)

Grant, Christopher V.; Yang, Yuan; Glibowicka, Mira; Wu, Chin H.; Park, Sang Ho; Deber, Charles M.; Opella, Stanley J.

2009-11-01

The design, construction, and performance of a cross-coil double-resonance probe for solid-state NMR experiments on lossy biological samples at high magnetic fields are described. The outer coil is a Modified Alderman-Grant Coil (MAGC) tuned to the 1H frequency. The inner coil consists of a multi-turn solenoid coil that produces a B 1 field orthogonal to that of the outer coil. This results in a compact nested cross-coil pair with the inner solenoid coil tuned to the low frequency detection channel. This design has several advantages over multiple-tuned solenoid coil probes, since RF heating from the 1H channel is substantially reduced, it can be tuned for samples with a wide range of dielectric constants, and the simplified circuit design and high inductance inner coil provides excellent sensitivity. The utility of this probe is demonstrated on two electrically lossy samples of membrane proteins in phospholipid bilayers (bicelles) that are particularly difficult for conventional NMR probes. The 72-residue polypeptide embedding the transmembrane helices 3 and 4 of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) (residues 194-241) requires a high salt concentration in order to be successfully reconstituted in phospholipid bicelles. A second application is to paramagnetic relaxation enhancement applied to the membrane-bound form of Pf1 coat protein in phospholipid bicelles where the resistance to sample heating enables high duty cycle solid-state NMR experiments to be performed.

Joint representation of translational and rotational components of optic flow in parietal cortex

PubMed Central

Sunkara, Adhira; DeAngelis, Gregory C.; Angelaki, Dora E.

2016-01-01

Terrestrial navigation naturally involves translations within the horizontal plane and eye rotations about a vertical (yaw) axis to track and fixate targets of interest. Neurons in the macaque ventral intraparietal (VIP) area are known to represent heading (the direction of self-translation) from optic flow in a manner that is tolerant to rotational visual cues generated during pursuit eye movements. Previous studies have also reported that eye rotations modulate the response gain of heading tuning curves in VIP neurons. We tested the hypothesis that VIP neurons simultaneously represent both heading and horizontal (yaw) eye rotation velocity by measuring heading tuning curves for a range of rotational velocities of either real or simulated eye movements. Three findings support the hypothesis of a joint representation. First, we show that rotation velocity selectivity based on gain modulations of visual heading tuning is similar to that measured during pure rotations. Second, gain modulations of heading tuning are similar for self-generated eye rotations and visually simulated rotations, indicating that the representation of rotation velocity in VIP is multimodal, driven by both visual and extraretinal signals. Third, we show that roughly one-half of VIP neurons jointly represent heading and rotation velocity in a multiplicatively separable manner. These results provide the first evidence, to our knowledge, for a joint representation of translation direction and rotation velocity in parietal cortex and show that rotation velocity can be represented based on visual cues, even in the absence of efference copy signals. PMID:27095846

Novel dynamic tuning of broadband visible metamaterial perfect absorber using graphene

NASA Astrophysics Data System (ADS)

Jia, Xiuli; Wang, Xiaoou; Yuan, Chengxun; Meng, Qingxin; Zhou, Zhongxiang

2016-07-01

We present a novel dynamic tuning of a broadband visible metamaterial absorber consisting of a multilayer-graphene-embedded nano-cross elliptical hole (MGENCEH) structure. It has multiple effects, including excitation of surface plasmon polaritons and extraordinary optical transmission in the first two metal layers. A numerical simulation shows that the MGENCEH structure can realize broadband perfect absorption (BPA) from 5.85 × 1014 to 6.5 × 1014 Hz over a wide incident angle range for transverse magnetic polarized light if the chemical potential of graphene (uc) is tuned to 1.0 eV. Furthermore, it has high broadband absorption (above 96%) from 4.6 × 1014 to 6.6 × 1014 Hz and three areas of narrowband perfect absorption around 4.65 × 1014, 5.1 × 1014, and 5.6 × 1014 Hz. The changes in the absorption spectra as a function of uc can be classically explained by simply considering plasmons as damped harmonic oscillators. This BPA is broader than the result of Zhou et al. [Opt. Express 23, A413-A418 (2015)] and is particularly desirable for various potential applications such as solar energy absorbers.

Three-dimensional cavity nanoantennas with resonant-enhanced surface plasmons as dynamic color-tuning reflectors.

PubMed

Fan, J R; Wu, W G; Chen, Z J; Zhu, J; Li, J

2017-03-09

As plasmonic antennas for surface-plasmon-assisted control of optical fields at specific frequencies, metallic nanostructures have recently emerged as crucial optical components for fascinating plasmonic color engineering. Particularly, plasmonic resonant nanocavities can concentrate lightwave energy to strongly enhance light-matter interactions, making them ideal candidates as optical elements for fine-tuning color displays. Inspired by the color mixing effect found on butterfly wings, a new type of plasmonic, multiresonant, narrow-band (the minimum is about 45 nm), high-reflectance (the maximum is about 95%), and dynamic color-tuning reflector is developed. This is achieved from periodic patterns of plasmonic resonant nanocavities in free-standing capped-pillar nanostructure arrays. Such cavity-coupling structures exhibit multiple narrow-band selective and continuously tunable reflections via plasmon standing-wave resonances. Consequently, they can produce a variety of dark-field vibrant reflective colors with good quality, strong color signal and fine tonal variation at the optical diffraction limit. This proposed multicolor scheme provides an elegant strategy for realizing personalized and customized applications in ultracompact photonic data storage and steganography, colorimetric sensing, 3D holograms and other plasmon-assisted photonic devices.

Dynamic response mitigation of floating wind turbine platforms using tuned liquid column dampers.

PubMed

Jaksic, V; Wright, C S; Murphy, J; Afeef, C; Ali, S F; Mandic, D P; Pakrashi, V

2015-02-28

In this paper, we experimentally study and compare the effects of three combinations of multiple tuned liquid column dampers (MTLCDs) on the dynamic performance of a model floating tension-leg platform (TLP) structure in a wave basin. The structural stability and safety of the floating structure during operation and maintenance is of concern for the performance of a renewable energy device that it might be supporting. The dynamic responses of the structure should thus be limited for these renewable energy devices to perform as intended. This issue is particularly important during the operation of a TLP in extreme weather conditions. Tuned liquid column dampers (TLCDs) can use the power of sloshing water to reduce surge motions of a floating TLP exposed to wind and waves. This paper demonstrates the potential of MTLCDs in reducing dynamic responses of a scaled TLP model through an experimental study. The potential of using output-only statistical markers for monitoring changes in structural conditions is also investigated through the application of a delay vector variance (DVV) marker for different conditions of control for the experiments. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

On the fusion of tuning parameters of fuzzy rules and neural network

NASA Astrophysics Data System (ADS)

Mamuda, Mamman; Sathasivam, Saratha

2017-08-01

Learning fuzzy rule-based system with neural network can lead to a precise valuable empathy of several problems. Fuzzy logic offers a simple way to reach at a definite conclusion based upon its vague, ambiguous, imprecise, noisy or missing input information. Conventional learning algorithm for tuning parameters of fuzzy rules using training input-output data usually end in a weak firing state, this certainly powers the fuzzy rule and makes it insecure for a multiple-input fuzzy system. In this paper, we introduce a new learning algorithm for tuning the parameters of the fuzzy rules alongside with radial basis function neural network (RBFNN) in training input-output data based on the gradient descent method. By the new learning algorithm, the problem of weak firing using the conventional method was addressed. We illustrated the efficiency of our new learning algorithm by means of numerical examples. MATLAB R2014(a) software was used in simulating our result The result shows that the new learning method has the best advantage of training the fuzzy rules without tempering with the fuzzy rule table which allowed a membership function of the rule to be used more than one time in the fuzzy rule base.

The Design of a Transparent Vertical Multizone Furnace: Application to Thermal Field Tuning and Crystal Growth

NASA Technical Reports Server (NTRS)

Duvual, Walter M. B.; Batur, Celal; Bennett, Robert J.

1998-01-01

We present an innovative design of a vertical transparent multizone furnace which can operate in the temperature range of 25 C to 750 C and deliver thermal gradients of 2 C/cm to 45 C/cm for the commercial applications to crystal growth. The operation of the eight zone furnace is based on a self-tuning temperature control system with a DC power supply for optimal thermal stability. We show that the desired thermal profile over the entire length of the furnace consists of a functional combination of the fundamental thermal profiles for each individual zone obtained by setting the set-point temperature for that zone. The self-tuning system accounts for the zone to zone thermal interactions. The control system operates such that the thermal profile is maintained under thermal load, thus boundary conditions on crystal growth ampoules can be predetermined prior to crystal growth. Temperature profiles for the growth of crystals via directional solidification, vapor transport techniques, and multiple gradient applications are shown to be easily implemented. The unique feature of its transparency and ease of programming thermal profiles make the furnace useful in scientific and commercial applications for determining the optimized process parameters for crystal growth.

Feasibility study of tuned liquid column damper for ocean wave energy extraction

NASA Astrophysics Data System (ADS)

Wong, Yihong; King, Yeong-Jin; Lai, An-Chow; Chong, Kok-Keong; Lim, Boon-Han

2017-04-01

Intermittent nature and low efficiency are the major issues in renewable energy supply. To overcome these issues, one of the possible methods is through a hybrid system where multiple sources of renewable energy are combined to compensate each other's weaknesses. The hybrid of solar energy and wave energy becomes possible through the introduction of a stable floating platform which enables solar energy generation above it and wave energy harvesting underneath it. This paper is intended to study the feasibility of harnessing ocean wave energy using a tuned liquid column damper (TLCD), a type of passive damping device that is designed to suppress externally induced vibration force at a specific frequency range. The proposed TLCD is to be implemented within a floating offshore structure to serve as a vibration mitigating mechanism by reducing the dynamic response of the structure and simultaneously utilize the flowing motion of liquid within the TLCD for generating electricity. The constructed TLCD prototype is tuned according to theoretical study and tested using a shaking table with a predetermined frequency range. The oscillating motion of water within the TLCD and the potential of installation of hydro turbine generator in term of recoverable amount of energy are studied.

Macromolecular scaffolding: the relationship between nanoscale architecture and function in multichromophoric arrays for organic electronics.

PubMed

Palermo, Vincenzo; Schwartz, Erik; Finlayson, Chris E; Liscio, Andrea; Otten, Matthijs B J; Trapani, Sara; Müllen, Klaus; Beljonne, David; Friend, Richard H; Nolte, Roeland J M; Rowan, Alan E; Samorì, Paolo

2010-02-23

The optimization of the electronic properties of molecular materials based on optically or electrically active organic building blocks requires a fine-tuning of their self-assembly properties at surfaces. Such a fine-tuning can be obtained on a scale up to 10 nm by mastering principles of supramolecular chemistry, i.e., by using suitably designed molecules interacting via pre-programmed noncovalent forces. The control and fine-tuning on a greater length scale is more difficult and challenging. This Research News highlights recent results we obtained on a new class of macromolecules that possess a very rigid backbone and side chains that point away from this backbone. Each side chain contains an organic semiconducting moiety, whose position and electronic interaction with neighboring moieties are dictated by the central macromolecular scaffold. A combined experimental and theoretical approach has made it possible to unravel the physical and chemical properties of this system across multiple length scales. The (opto)electronic properties of the new functional architectures have been explored by constructing prototypes of field-effect transistors and solar cells, thereby providing direct insight into the relationship between architecture and function.

Quantum oscillations in the heavy-fermion compound YbPtBi

DOE PAGES

Mun, E.; Bud'ko, S. L.; Lee, Y.; ...

2015-08-01

We present quantum oscillations observed in the heavy-fermion compound YbPtBi in magnetic fields far beyond its field-tuned, quantum critical point. Quantum oscillations are observed in magnetic fields as low as 60 kOe at 60 mK and up to temperatures as high as 3 K, which confirms the very high quality of the samples as well as the small effective mass of the conduction carriers far from the quantum critical point. Although the electronic specific heat coefficient of YbPtBi reaches ~7.4 J/molK 2 in zero field, which is one of the highest effective mass values among heavy-fermion systems, we suppress itmore » quickly by an applied magnetic field. The quantum oscillations were used to extract the quasiparticle effective masses of the order of the bare electron mass, which is consistent with the behavior observed in specific heat measurements. Furthermore, such small effective masses at high fields can be understood by considering the suppression of Kondo screening.« less

Effects of emission layer doping on the spatial distribution of charge and host recombination rate density in organic light emitting devices: A numerical study

NASA Astrophysics Data System (ADS)

Li, Yanli; Zhou, Maoqing; Zheng, Tingcai; Yao, Bo; Peng, Yingquan

2013-12-01

Based on drift-diffusion theory, a numerical model of the doping of a single energy level trap in the emission layer of an organic light emitting device (OLED) was developed, and the effects of doping of this single energy level trap on the distribution of the charge density, the recombination rate density, and the electric field in single- and double-layer OLEDs were studied numerically. The results show that by doping the n-type (p-type) emission layer with single energy electron (hole) traps, the distribution of the recombination rate density can be tuned and shifted, which is useful for improvement of the device performance by reduced electrode quenching or for realization of desirable special functions, e.g., emission spectrum tuning in multiple dye-doped white OLEDs.

Underground tuning: quantitative regulation of root growth.

PubMed

Satbhai, Santosh B; Ristova, Daniela; Busch, Wolfgang

2015-02-01

Plants display a high degree of phenotypic plasticity that allows them to tune their form and function to changing environments. The plant root system has evolved mechanisms to anchor the plant and to efficiently explore soils to forage for soil resources. Key to this is an enormous capacity for plasticity of multiple traits that shape the distribution of roots in the soil. Such root system architecture-related traits are determined by root growth rates, root growth direction, and root branching. In this review, we describe how the root system is constituted, and which mechanisms, pathways, and genes mainly regulate plasticity of the root system in response to environmental variation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Potassium Homeostasis: The Knowns, the Unknowns, and the Health Benefits.

PubMed

McDonough, Alicia A; Youn, Jang H

2017-03-01

Potassium homeostasis has a very high priority because of its importance for membrane potential. Although extracellular K + is only 2% of total body K + , our physiology was evolutionarily tuned for a high-K + , low-Na + diet. We review how multiple systems interface to accomplish fine K + balance and the consequences for health and disease. ©2017 Int. Union Physiol. Sci./Am. Physiol. Soc.

Electron-Focus Adjustment for Photo-Optical Imagers

NASA Technical Reports Server (NTRS)

Fowler, Walter B.; Flemming, Keith; Ziegler, Michael M.

1987-01-01

Internal electron focus made independent of optical focus. Procedure enables fine tuning of internal electron-focusing system of photo-optical imager, without complication by imperfections of associated external optics. Applicable to imager in which electrons emitted from photocathode in optical focal plane, then electrostatically and/or magnetically focused to replica of image in second focal plane containing photodiodes, phototransistorss, charge-coupled devices, multiple-anode outputs, or other detectors.

Software for Automated Image-to-Image Co-registration

NASA Technical Reports Server (NTRS)

Benkelman, Cody A.; Hughes, Heidi

2007-01-01

The project objectives are: a) Develop software to fine-tune image-to-image co-registration, presuming images are orthorectified prior to input; b) Create a reusable software development kit (SDK) to enable incorporation of these tools into other software; d) provide automated testing for quantitative analysis; and e) Develop software that applies multiple techniques to achieve subpixel precision in the co-registration of image pairs.

A MULTIPLICITY CENSUS OF INTERMEDIATE-MASS STARS IN SCORPIUS-CENTAURUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janson, Markus; Lafreniere, David; Jayawardhana, Ray

2013-08-20

Stellar multiplicity properties have been studied for the lowest and the highest stellar masses, but intermediate-mass stars from F-type to late A-type have received relatively little attention. Here, we report on a Gemini/NICI snapshot imaging survey of 138 such stars in the young Scorpius-Centaurus (Sco-Cen) region, for the purpose of studying multiplicity with sensitivity down to planetary masses at wide separations. In addition to two brown dwarfs and a companion straddling the hydrogen-burning limit which we reported previously, here we present 26 new stellar companions and determine a multiplicity fraction within 0.''1-5.''0 of 21% {+-} 4%. Depending on the adoptedmore » semimajor axis distribution, our results imply a total multiplicity in the range of {approx}60%-80%, which further supports the known trend of a smooth continuous increase in the multiplicity fraction as a function of primary stellar mass. A surprising feature in the sample is a distinct lack of nearly equal-mass binaries, for which we discuss possible reasons. The survey yielded no additional companions below or near the deuterium-burning limit, implying that their frequency at >200 AU separations is not quite as high as might be inferred from previous detections of such objects within the Sco-Cen region.« less

Gas Cloud Accretion onto the SMBH SgrA* and Formation of Jet 4

NASA Astrophysics Data System (ADS)

Nishiyama, Shogo

2015-06-01

A dense gas cloud was detected to be rapidly approaching the Galactic supermassive black hole (SMBH) Sgr A*, and was 1,600 Schwarzschild radii from the SMBH at the pericenter of its eccentric orbit in Mar 2014. Ongoing tidal disruption has been observed, and cloud fragments are expected to accrete onto the SMBH on dynamical timescales, suggesting a jet formation in the following years. So we are carrying out daily monitoring observations of Sgr A* in near-infrared and radio wavelengths, and we propose quick follow-up observations with Subaru/Gemini. Br-gamma line emission maps obtained with Gemini/NIFS will be used to fine tune our 3D simulation to estimate how much mass accretes, and when the fragments accrete onto the SMBH. Polarimetric and astrometric signals from a jet taken with Subaru/HiCIAO and KaVA will be compared with the finely tuned simulation to understand the timescale of jet formation, and to investigate the correlation between the accreted mass of the cloud fragments and a luminosity of the newly-formed jet. Spectroscopic and imaging observations from 1.6 - 11 mum (Subaru/IRCS, COMICS) will also be conducted to understand processes responsible for near to mid-infrared emission during the accretion event.

Longitudinal wave function control in single quantum dots with an applied magnetic field

PubMed Central

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-01

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018

Longitudinal wave function control in single quantum dots with an applied magnetic field.

PubMed

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-27

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots.

Protoplanetary disks in Taurus: Probing the role of multiplicity with ALMA observations

NASA Astrophysics Data System (ADS)

Laos, Stefan; Akeson, Rachel L.; Jensen, Eric L. N.

2017-01-01

We present results from an ALMA survey of single and multiple young systems in Taurus designed to probe how protoplanetary disk mass depends on both stellar mass and multiplicity. In observations taken in Cycles 0 and 2, we detect over 25 new disks. These detections include disks around stars in both single and multiple systems and are predominantly around lower mass stars with spectral types from M0 to M6. Combined with previous detections, these observations reveal a wide range of disk mass around both primary and companion stars, and allow us to test if the relation previously seen between disk and stellar mass continues at lower stellar masses. We find that within multiple systems the ratio of primary to secondary stellar mass is not correlated with the ratio of primary to secondary disk mass. In some cases, the secondary star hosts the more massive disk, contrary to theoretical predictions. We will discuss the implications of these results for the process of planet formation in multiple systems.This work makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00150.S. and ADS/JAO.ALMA#2013.1.00105.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

On Identifiability of Bias-Type Actuator-Sensor Faults in Multiple-Model-Based Fault Detection and Identification

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.

2012-01-01

This paper explores a class of multiple-model-based fault detection and identification (FDI) methods for bias-type faults in actuators and sensors. These methods employ banks of Kalman-Bucy filters to detect the faults, determine the fault pattern, and estimate the fault values, wherein each Kalman-Bucy filter is tuned to a different failure pattern. Necessary and sufficient conditions are presented for identifiability of actuator faults, sensor faults, and simultaneous actuator and sensor faults. It is shown that FDI of simultaneous actuator and sensor faults is not possible using these methods when all sensors have biases.

Tunable Multiple Plasmon-Induced Transparencies Based on Asymmetrical Graphene Nanoribbon Structures

PubMed Central

Lu, Chunyu; Wang, Jicheng; Yan, Shubin; Hu, Zheng-Da; Zheng, Gaige; Yang, Liu

2017-01-01

We present plasmonic devices, consisting of periodic arrays of graphene nanoribbons (GNRs) and a graphene sheet waveguide, to achieve controllable plasmon-induced transparency (PIT) by numerical simulation. We analyze the bright and dark elements of the GNRs and graphene-sheet waveguide structure. Results show that applying the gate voltage can electrically tune the PIT spectrum. Adjusting the coupling distance and widths of GNRs directly results in a shift of transmission dips. In addition, increased angle of incidence causes the transmission to split into multiple PIT peaks. We also demonstrate that PIT devices based on graphene plasmonics may have promising applications as plasmonic sensors in nanophotonics. PMID:28773062

CO2 DIAL system: construction, measurements, and future development

NASA Astrophysics Data System (ADS)

Vicenik, Jiri

1999-07-01

A miniature CO2 DIAL system has been constructed. Dimension of the system are 500 X 450 X 240 mm, its mass is only 28 kg. The system consists of two tunable TEA CO2 lasers, receiving optics, IR detector, signal processing electronics and single chip microcomputer with display. The lasers are tuned manually by means of micrometric screw and are capable to generate pulses on more than 50 CO2 laser lines. The output energy is 50 mJ. The system was tested using various toxic gases and simulants, mostly at range 300 m, most of the measurements were done using pyrodetector in the receiver. The system shows good sensitivity, but it exhibits substantial instability of zero concentration. In the next stage the work will be concentrated on use of high-sensitivity MCT detector in the receiver and implementation of automatic tuning of lasers to the system.

Maximum efficiency of the collisional Penrose process

NASA Astrophysics Data System (ADS)

Zaslavskii, O. B.

2016-09-01

We consider the collision of two particles that move in the equatorial plane near a general stationary rotating axially symmetric extremal black hole. One of the particles is critical (with fine-tuned parameters) and moves in the outward direction. The second particle (usual, not fine-tuned) comes from infinity. We examine the efficiency η of the collisional Penrose process. There are two relevant cases here: a particle falling into a black hole after collision (i) is heavy or (ii) has a finite mass. We show that the maximum of η in case (ii) is less than or equal to that in case (i). It is argued that for superheavy particles, the bound applies to nonequatorial motion as well. As an example, we analyze collision in the Kerr-Newman background. When the bound is the same for processes (i) and (ii), η =3 for this metric. For the Kerr black hole, recent results in the literature are reproduced.

Thermal tuning on band gaps of 2D phononic crystals considering adhesive layers

NASA Astrophysics Data System (ADS)

Zhou, Xiaoliang; Chen, Jialin; Li, Yuhang; Sun, Yuxin; Xing, Yufeng

2018-02-01

Phononic crystals are very attractive in many applications, such as noise reduction, filters and vibration isolation, due to their special forbidden band gap structures. In the present paper, the investigation of tunable band gaps of 2D phononic crystals with adhesive layers based on thermal changing is conducted. Based on the lumped-mass method, an analytical model of 2D phononic crystals with relatively thin adhesive layers is established, in which the in-plane and out-of-plane modes are both in consideration. The adhesive material is sensitive to temperature so that the band structure can be tuned and controlled by temperature variation. As temperature increases from 20 °C-80 °C, the first band gap shifts to the frequency zone around 10 kHz, which is included by the audible frequency range. The results propose an important guideline for applications, such as noise suppression using the 2D phononic crystals.

Magnetotunneling spectroscopy of dilute Ga(AsN) quantum wells.

PubMed

Endicott, J; Patanè, A; Ibáñez, J; Eaves, L; Bissiri, M; Hopkinson, M; Airey, R; Hill, G

2003-09-19

We use magnetotunneling spectroscopy to explore the admixing of the extended GaAs conduction band states with the localized N-impurity states in dilute GaAs(1-y)N(y) quantum wells. In our resonant tunneling diodes, electrons can tunnel into the N-induced E- and E+ subbands in a GaAs(1-y)N(y) quantum well layer, leading to resonant peaks in the current-voltage characteristics. By varying the magnetic field applied perpendicular to the current direction, we can tune an electron to tunnel into a given k state of the well; since the applied voltage tunes the energy, we can map out the form of the energy-momentum dispersion curves of E- and E+. The data reveal that for a small N content (approximately 0.1%) the E- and E+ subbands are highly nonparabolic and that the heavy effective mass E+ states have a significant Gamma-conduction band character even at k=0.

Creating a Test Validated Structural Dynamic Finite Element Model of the Multi-Utility Technology Test Bed Aircraft

NASA Technical Reports Server (NTRS)

Pak, Chan-Gi; Truong, Samson S.

2014-01-01

Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of Multi Utility Technology Test Bed, X-56A, aircraft is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of X-56A. The ground vibration test validated structural dynamic finite element model of the X-56A is created in this study. The structural dynamic finite element model of the X-56A is improved using a model tuning tool. In this study, two different weight configurations of the X-56A have been improved in a single optimization run.

Cornering natural SUSY at LHC Run II and beyond

NASA Astrophysics Data System (ADS)

Buckley, Matthew R.; Feld, David; Macaluso, Sebastian; Monteux, Angelo; Shih, David

2017-08-01

We derive the latest constraints on various simplified models of natural SUSY with light higgsinos, stops and gluinos, using a detailed and comprehensive reinterpretation of the most recent 13 TeV ATLAS and CMS searches with ˜ 15 fb-1 of data. We discuss the implications of these constraints for fine-tuning of the electroweak scale. While the most "vanilla" version of SUSY (the MSSM with R-parity and flavor-degenerate sfermions) with 10% fine-tuning is ruled out by the current constraints, models with decoupled valence squarks or reduced missing energy can still be fully natural. However, in all of these models, the mediation scale must be extremely low ( <100 TeV). We conclude by considering the prospects for the high-luminosity LHC era, where we expect the current limits on particle masses to improve by up to ˜ 1 TeV, and discuss further model-building directions for natural SUSY that are motivated by this work.

Universal structures of normal and pathological heart rate variability.

PubMed

Gañán-Calvo, Alfonso M; Fajardo-López, Juan

2016-02-25

The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient.

Mechanical characterisation of the TorPeDO: a low frequency gravitational force sensor

NASA Astrophysics Data System (ADS)

McManus, D. J.; Forsyth, P. W. F.; Yap, M. J.; Ward, R. L.; Shaddock, D. A.; McClelland, D. E.; Slagmolen, B. J. J.

2017-07-01

Newtonian noise is likely to be a future challenge at low frequencies for Advanced LIGO and other second generation gravitational wave detectors. We present the TorPeDO system: a dual torsion pendulum sensor designed to measure local gravitational forces to high precision. Gravitational forces induce a differential rotation between the two torsion beams, which is measured with an optical read-out. Both torsion pendulums have a common suspension point, tunable centre of mass, and resonant frequency. This produces a high level of mechanical common mode noise cancellation. We report on a controls prototype of the TorPeDO system, presenting the frequency response and tuning range of both pendulums. A noise budget and mechanical cross-coupling model for this system are also presented. We demonstrate frequency tuning of the two torsion pendulums to a difference of 4.3 μHz.

Widely tunable (PbSn)Te lasers using etched cavities for mass production. [for infrared spectroscopic applications

NASA Technical Reports Server (NTRS)

Miller, M. D.

1980-01-01

Lead salt diode lasers are being used increasingly as tunable sources of monochromatic infrared radiation in a variety of spectroscopic systems. These devices are particularly useful, both in the laboratory and in the field, because of their high spectral brightness (compared to thermal sources) and wide spectral coverage (compared to line-tunable gas lasers). While the primary commercial application of these lasers has been for ultrahigh resolution laboratory spectroscopy, there are numerous systems applications, including laser absorbtion pollution monitors and laser heterodyne radiometers, for which diode lasers have great potential utility. Problem areas related to the wider use of these components are identified. Among these are total tuning range, mode control, and high fabrication cost. A fabrication technique which specifically addresses the problems of tuning range and cost, and which also has potential application for mode control, is reported.

Thin film beam splitter multiple short pulse generation for enhanced Ni-like Ag x-ray laser emission.

PubMed

Cojocaru, Gabriel V; Ungureanu, Razvan G; Banici, Romeo A; Ursescu, Daniel; Delmas, Olivier; Pittman, Moana; Guilbaud, Olivier; Kazamias, Sophie; Cassou, Kevin; Demailly, Julien; Neveu, Olivier; Baynard, Elsa; Ros, David

2014-04-15

An alternative, novel multiple pulse generation scheme was implemented directly after the optical compressor output of an x-ray pump laser. The new method uses a polarization sensitive thin film beam splitter and a half-wavelength wave plate for tuning the energy ratio in the multiple short pulses. Based on this method, an extensive study was made of the running parameters for a grazing incidence pumped silver x-ray laser (XRL) pumped with a long pulse of 145 mJ in 6 ns at 532 nm and up to 1.45 J in few picoseconds at 810 nm. Fivefold enhancement in the emission of the silver XRL was demonstrated using the new pump method.

Unified dead-time compensation structure for SISO processes with multiple dead times.

PubMed

Normey-Rico, Julio E; Flesch, Rodolfo C C; Santos, Tito L M

2014-11-01

This paper proposes a dead-time compensation structure for processes with multiple dead times. The controller is based on the filtered Smith predictor (FSP) dead-time compensator structure and it is able to control stable, integrating, and unstable processes with multiple input/output dead times. An equivalent model of the process is first computed in order to define the predictor structure. Using this equivalent model, the primary controller and the predictor filter are tuned to obtain an internally stable closed-loop system which also attempts some closed-loop specifications in terms of set-point tracking, disturbance rejection, and robustness. Some simulation case studies are used to illustrate the good properties of the proposed approach. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Low temperature probe for dynamic nuclear polarization and multiple-pulse solid-state NMR.

PubMed

Cho, HyungJoon; Baugh, Jonathan; Ryan, Colm A; Cory, David G; Ramanathan, Chandrasekhar

2007-08-01

Here, we describe the design and performance characteristics of a low temperature probe for dynamic nuclear polarization (DNP) experiments, which is compatible with demanding multiple-pulse experiments. The competing goals of a high-Q microwave cavity to achieve large DNP enhancements and a high efficiency NMR circuit for multiple-pulse control lead to inevitable engineering tradeoffs. We have designed two probes-one with a single-resonance RF circuit and a horn-mirror cavity configuration for the microwaves and a second with a double-resonance RF circuit and a double-horn cavity configuration. The advantage of the design is that the sample is in vacuum, the RF circuits are locally tuned, and the microwave resonator has a large internal volume that is compatible with the use of RF and gradient coils.

Experimental studies of systematic multiple-energy operation at HIMAC synchrotron

NASA Astrophysics Data System (ADS)

Mizushima, K.; Katagiri, K.; Iwata, Y.; Furukawa, T.; Fujimoto, T.; Sato, S.; Hara, Y.; Shirai, T.; Noda, K.

2014-07-01

Multiple-energy synchrotron operation providing carbon-ion beams with various energies has been used for scanned particle therapy at NIRS. An energy range from 430 to 56 MeV/u and about 200 steps within this range are required to vary the Bragg peak position for effective treatment. The treatment also demands the slow extraction of beam with highly reliable properties, such as spill, position and size, for all energies. We propose an approach to generating multiple-energy operation meeting these requirements within a short time. In this approach, the device settings at most energy steps are determined without manual adjustments by using systematic parameter tuning depending on the beam energy. Experimental verification was carried out at the HIMAC synchrotron, and its results proved that this approach can greatly reduce the adjustment period.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, O.L.

A first-principles model of a nominal 20-MW atmospheric-pressure fluidized-bed coal combustion (AFBC) power plant was developed to provide insight into fundamental dynamic behavior of fluidized-bed systems. The control system included major loops for firing rate, steam pressure and temperature, forced and induced draft air flow, SO/sub 2/ emission, drum water level, evaporator recirculation, and bed level. The model was used to investigate system sensitivity to design features such as the distribution of heat transfer surface among the bed boiler and superheater and the out-of-bed superheater. Also calculated were the sensitivities of temperatures, pressures, and flow rates to changes in throttle,more » attemperator, and feedwater valve settings and forced and induced draft damper settings. The large bed mass, accounting for approx.40% of the active heat capacity, may vary under load change and could impact controller tuning. Model analysis indicated, however, that for the design studied, the change in bed mass does not appear to significantly affect controller tuning even if the bed mass varies appreciably under load-following conditions. Several bed designs are being considered for AFBC plants, some with partitions between bed sections and some without, and these differences may significantly affect the load-following capability of the plant. The results indicated that the slumping mode of operation can cause distortion of the heat source/sink distribution in the bed such that the load-following capability (rate of load change) of the plant may be reduced by as much as a factor of 5 compared with the mode in which tube surface is exposed. 9 refs., 13 figs., 6 tabs.« less

Low-lying baryon spectrum with two dynamical twisted mass fermions

NASA Astrophysics Data System (ADS)

Alexandrou, C.; Baron, R.; Carbonell, J.; Drach, V.; Guichon, P.; Jansen, K.; Korzec, T.; Pène, O.

2009-12-01

The masses of the low-lying baryons are evaluated using two degenerate flavors of twisted mass sea quarks corresponding to pseudoscalar masses in the range of about 270-500 MeV. The strange valence quark mass is tuned to reproduce the mass of the kaon in the physical limit. The tree-level Symanzik improved gauge action is employed. We use lattices of spatial size 2.1 and 2.7 fm at two values of the lattice spacing with r0/a=5.22(2) and r0/a=6.61(3). We check for both finite volume and cutoff effects on the baryon masses. We performed a detailed study of the chiral extrapolation of the octet and decuplet masses using SU(2) χPT. The lattice spacings determined using the nucleon mass at the physical point are consistent with the values extracted using the pion decay constant. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. The baryon masses that we find after taking the continuum limit and extrapolating to the physical limit are in good agreement with experiment.

Leading isospin-breaking corrections to pion, kaon, and charmed-meson masses with twisted-mass fermions

NASA Astrophysics Data System (ADS)

Giusti, D.; Lubicz, V.; Tarantino, C.; Martinelli, G.; Sanfilippo, F.; Simula, S.; Tantalo, N.; RM123 Collaboration

2017-06-01

We present a lattice computation of the isospin-breaking corrections to pseudoscalar meson masses using the gauge configurations produced by the European Twisted Mass Collaboration with Nf=2 +1 +1 dynamical quarks at three values of the lattice spacing (a ≃0.062 , 0.082, and 0.089 fm) with pion masses in the range Mπ≃210 - 450 MeV . The strange and charm quark masses are tuned at their physical values. We adopt the RM123 method based on the combined expansion of the path integral in powers of the d - and u -quark mass difference (m^d-m^u) and of the electromagnetic coupling αe m. Within the quenched QED approximation, which neglects the effects of the sea-quark charges, and after the extrapolations to the physical pion mass and to the continuum and infinite volume limits, we provide results for the pion, kaon, and (for the first time) charmed-meson mass splittings, for the prescription-dependent parameters ɛπ0, ɛγ(M S ¯ ,2 GeV ) , ɛK0(M S ¯ ,2 GeV ) , related to the violations of the Dashen's theorem, and for the light quark mass difference (m^ d-m^ u)(M S ¯ ,2 GeV ) .

Activation of the Basolateral Amygdala Induces Long-Term Enhancement of Specific Memory Representations in the Cerebral Cortex

PubMed Central

Chavez, Candice M.; McGaugh, James L.; Weinberger, Norman M.

2013-01-01

The basolateral amygdala (BLA) modulates memory, particularly for arousing or emotional events, during post-training periods of consolidation. It strengthens memories whose substrates in part or whole are stored remotely, in structures such as the hippocampus, striatum and cerebral cortex. However, the mechanisms by which the BLA influences distant memory traces are unknown, largely because of the need for identifiable target mnemonic representations. Associative tuning plasticity in the primary auditory cortex (A1) constitutes a well-characterized candidate specific memory substrate that is ubiquitous across species, tasks and motivational states. When tone predicts reinforcement, the tuning of cells in A1 shifts toward or to the signal frequency within its tonotopic map, producing an over-representation of behaviorally important sounds. Tuning shifts have the cardinal attributes of forms of memory, including associativity, specificity, rapid induction, consolidation and long-term retention and are therefore likely memory representations. We hypothesized that the BLA strengthens memories by increasing their cortical representations. We recorded multiple unit activity from A1 of rats that received a single discrimination training session in which two tones (2.0 s) separated by 1.25 octaves were either paired with brief electrical stimulation (400 ms) of the BLA (CS+) or not (CS−). Frequency response areas generated by presenting a matrix of test tones (0.5–53.82 kHz, 0–70 dB) were obtained before training and daily for three weeks post-training. Tuning both at threshold and above threshold shifted predominantly toward the CS+ beginning on Day 1. Tuning shifts were maintained for the entire three weeks. Absolute threshold and bandwidth decreased, producing less enduring increases in sensitivity and selectivity. BLA-induced tuning shifts were associative, highly specific and long-lasting. We propose that the BLA strengthens memory for important experiences by increasing the number of neurons that come to best represent that event. Traumatic, intrusive memories might reflect abnormally extensive representational networks due to hyper-activity of the BLA consequent to the release of excessive amounts of stress hormones. PMID:23266792

High-Performance High-Order Simulation of Wave and Plasma Phenomena

NASA Astrophysics Data System (ADS)

Klockner, Andreas

This thesis presents results aiming to enhance and broaden the applicability of the discontinuous Galerkin ("DG") method in a variety of ways. DG was chosen as a foundation for this work because it yields high-order finite element discretizations with very favorable numerical properties for the treatment of hyperbolic conservation laws. In a first part, I examine progress that can be made on implementation aspects of DG. In adapting the method to mass-market massively parallel computation hardware in the form of graphics processors ("GPUs"), I obtain an increase in computation performance per unit of cost by more than an order of magnitude over conventional processor architectures. Key to this advance is a recipe that adapts DG to a variety of hardware through automated self-tuning. I discuss new parallel programming tools supporting GPU run-time code generation which are instrumental in the DG self-tuning process and contribute to its reaching application floating point throughput greater than 200 GFlops/s on a single GPU and greater than 3 TFlops/s on a 16-GPU cluster in simulations of electromagnetics problems in three dimensions. I further briefly discuss the solver infrastructure that makes this possible. In the second part of the thesis, I introduce a number of new numerical methods whose motivation is partly rooted in the opportunity created by GPU-DG: First, I construct and examine a novel GPU-capable shock detector, which, when used to control an artificial viscosity, helps stabilize DG computations in gas dynamics and a number of other fields. Second, I describe my pursuit of a method that allows the simulation of rarefied plasmas using a DG discretization of the electromagnetic field. Finally, I introduce new explicit multi-rate time integrators for ordinary differential equations with multiple time scales, with a focus on applicability to DG discretizations of time-dependent problems.

Mass spectrum and decay constants of radially excited vector mesons

NASA Astrophysics Data System (ADS)

Mojica, Fredy F.; Vera, Carlos E.; Rojas, Eduardo; El-Bennich, Bruno

2017-07-01

We calculate the masses and weak decay constants of flavorless and flavored ground and radially excited JP=1- mesons within a Poincaré covariant continuum framework based on the Bethe-Salpeter equation. We use in both the quark's gap equation and the meson bound-state equation an infrared massive and finite interaction in the leading symmetry-preserving truncation. While our numerical results are in rather good agreement with experimental values where they are available, no single parametrization of the QCD inspired interaction reproduces simultaneously the ground and excited mass spectrum, which confirms earlier work on pseudoscalar mesons. This feature being a consequence of the lowest truncation, we pin down the range and strength of the interaction in both cases to identify common qualitative features that may help to tune future interaction models beyond the rainbow-ladder approximation.

Tunable semiconductor lasers

NASA Technical Reports Server (NTRS)

Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

2006-01-01

Tunable semiconductor lasers are disclosed requiring minimized coupling regions. Multiple laser embodiments employ ring resonators or ring resonator pairs using only a single coupling region with the gain medium are detailed. Tuning can be performed by changing the phase of the coupling coefficient between the gain medium and a ring resonator of the laser. Another embodiment provides a tunable laser including two Mach-Zehnder interferometers in series and a reflector coupled to a gain medium.

spammpack, Version 2013-06-18

DOE Office of Scientific and Technical Information (OSTI.GOV)

2014-01-17

This library is an implementation of the Sparse Approximate Matrix Multiplication (SpAMM) algorithm introduced. It provides a matrix data type, and an approximate matrix product, which exhibits linear scaling computational complexity for matrices with decay. The product error and the performance of the multiply can be tuned by choosing an appropriate tolerance. The library can be compiled for serial execution or parallel execution on shared memory systems with an OpenMP capable compiler

Excitatory, inhibitory and facilitatory frequency response areas in the inferior colliculus of hearing impaired mice.

PubMed

Felix, Richard A; Portfors, Christine V

2007-06-01

Individuals with age-related hearing loss often have difficulty understanding complex sounds such as basic speech. The C57BL/6 mouse suffers from progressive sensorineural hearing loss and thus is an effective tool for dissecting the neural mechanisms underlying changes in complex sound processing observed in humans. Neural mechanisms important for processing complex sounds include multiple tuning and combination sensitivity, and these responses are common in the inferior colliculus (IC) of normal hearing mice. We examined neural responses in the IC of C57Bl/6 mice to single and combinations of tones to examine the extent of spectral integration in the IC after age-related high frequency hearing loss. Ten percent of the neurons were tuned to multiple frequency bands and an additional 10% displayed non-linear facilitation to the combination of two different tones (combination sensitivity). No combination-sensitive inhibition was observed. By comparing these findings to spectral integration properties in the IC of normal hearing CBA/CaJ mice, we suggest that high frequency hearing loss affects some of the neural mechanisms in the IC that underlie the processing of complex sounds. The loss of spectral integration properties in the IC during aging likely impairs the central auditory system's ability to process complex sounds such as speech.

Interpolating between random walks and optimal transportation routes: Flow with multiple sources and targets

NASA Astrophysics Data System (ADS)

Guex, Guillaume

2016-05-01

In recent articles about graphs, different models proposed a formalism to find a type of path between two nodes, the source and the target, at crossroads between the shortest-path and the random-walk path. These models include a freely adjustable parameter, allowing to tune the behavior of the path toward randomized movements or direct routes. This article presents a natural generalization of these models, namely a model with multiple sources and targets. In this context, source nodes can be viewed as locations with a supply of a certain good (e.g. people, money, information) and target nodes as locations with a demand of the same good. An algorithm is constructed to display the flow of goods in the network between sources and targets. With again a freely adjustable parameter, this flow can be tuned to follow routes of minimum cost, thus displaying the flow in the context of the optimal transportation problem or, by contrast, a random flow, known to be similar to the electrical current flow if the random-walk is reversible. Moreover, a source-targetcoupling can be retrieved from this flow, offering an optimal assignment to the transportation problem. This algorithm is described in the first part of this article and then illustrated with case studies.

Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback

PubMed Central

Liu, Haoting; Zhou, Qianxiang; Yang, Jin; Jiang, Ting; Liu, Zhizhen; Li, Jie

2017-01-01

An imaging sensor-based intelligent Light Emitting Diode (LED) lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs) are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes. PMID:28208781

Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback.

PubMed

Liu, Haoting; Zhou, Qianxiang; Yang, Jin; Jiang, Ting; Liu, Zhizhen; Li, Jie

2017-02-09

An imaging sensor-based intelligent Light Emitting Diode (LED) lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs) are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes.

Tuning of few-electron states and optical absorption anisotropy in GaAs quantum rings.

PubMed

Wu, Zhenhua; Li, Jian; Li, Jun; Yin, Huaxiang; Liu, Yu

2017-11-15

The electronic and optical properties of a GaAs quantum ring (QR) with few electrons in the presence of the Rashba spin-orbit interaction (RSOI) and the Dresselhaus spin-orbit interaction (DSOI) have been investigated theoretically. The configuration interaction (CI) method is employed to calculate the eigenvalues and eigenstates of the multiple-electron QR accurately. Our numerical results demonstrate that the symmetry breaking induced by the RSOI and DSOI leads to an anisotropic distribution of multi-electron states. The Coulomb interaction offers additional modulation of the electron distribution and thus the optical absorption indices in the quantum rings. By tuning the magnetic/electric fields and/or electron numbers in a quantum ring, one can change its optical properties significantly. Our theory provides a new way to control the multi-electron states and optical properties of a QR by hybrid modulations or by electrical means only.

Multi-regulatory network of ROS: the interconnection of ROS, PGC-1 alpha, and AMPK-SIRT1 during exercise.

PubMed

Thirupathi, Anand; de Souza, Claudio Teodoro

2017-11-01

Transcriptional factors are easily susceptible to any stimuli, including exercise. Exercise can significantly influence PGC-1 α and AMPK-SIRT1 pathway, as it is involved in the regulation of energy metabolism and mitochondrial biogenesis. Exercise is a major energy deprivation process by which many of transcription factors get tuned positively. However, how transcription factors help to boost the antioxidant defense system at cellular level is elusive. It is well known that physical exercise can induce reactive oxygen species, but how these reactive oxygen species can help to regulate multiple transcription factors during exercise is an important area to be discussed yet. This review mainly focuses on interconnecting role of PGC-1 α and AMPK-SIRT1 pathway during exercise and how these proteins are getting tuned by reactive oxygen species in exercise condition.

Atmospheric methane measurement instrument using a Zeeman-split He-Ne laser

NASA Technical Reports Server (NTRS)

Mcmanus, J. Barry; Kebabian, Paul L.; Kolb, Charles E.

1989-01-01

The construction of an atmospheric methane measurement instrument based on a Zeeman-split IR He-Ne laser is reported. The laser has a tranverse magnetic field over about 2/3 of its gain length and can oscillate at an (unsplit) frequency (2947.91/cm) centered on a methane absorption line, or on either of two frequencies split by + or - 0.055/cm from the center, with low CH4 absorption. The laser is tuned to dwell sequentially at each frequency, giving two differential absorption measurements in each 46-ms tuning cycle. Atmospheric measurements are made using two multiple pass absorption cells, one with fast (0.75-s) and one with slow (5-s) flow response times. Fluctuations in ambient CH4 of about 20-ppb (rms, 1-s averaging) are detected, with interference fringe effects the dominant noise source. The instrument has operated in a field experiment (NASA GTE/ABLE-3A) in Alaska.

Potassium doping: Tuning the optical properties of graphene quantum dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Fuli; Li, Xueming, E-mail: lxmscience@163.com; Lu, Chaoyu

2016-07-15

Doping with hetero-atoms is an effective way to tune the properties of graphene quantum dots (GQDs). Here, potassium-doped GQDs (K-GQDs) are synthesized by a one-pot hydrothermal treatment of sucrose and potassium hydroxide solution. Optical properties of the GQDs are altered as a result of K-doping. The absorption peaks exhibit a blue shift. Multiple photoluminescence (PL) peaks are observed as the excitation wavelength is varied from 380 nm to 620 nm. New energy levels are introduced into the K-GQDs and provide alternative electron transition pathways. The maximum PL intensity of the K-GQDs is obtained at an excitation wavelength of 480 nmmore » which is distinct from the undoped GQDs (375 nm). The strong PL of the K-GQDs at the longer emission wavelengths is expected to make K-GQDs more suitable for bioimaging and optoelectronic applications.« less

Local tuning of the order parameter in superconducting weak links: A zero-inductance nanodevice

NASA Astrophysics Data System (ADS)

Winik, Roni; Holzman, Itamar; Dalla Torre, Emanuele G.; Buks, Eyal; Ivry, Yachin

2018-03-01

Controlling both the amplitude and the phase of the superconducting quantum order parameter (" separators="|ψ ) in nanostructures is important for next-generation information and communication technologies. The lack of electric resistance in superconductors, which may be advantageous for some technologies, hinders convenient voltage-bias tuning and hence limits the tunability of ψ at the microscopic scale. Here, we demonstrate the local tunability of the phase and amplitude of ψ, obtained by patterning with a single lithography step a Nb nano-superconducting quantum interference device (nano-SQUID) that is biased at its nanobridges. We accompany our experimental results by a semi-classical linearized model that is valid for generic nano-SQUIDs with multiple ports and helps simplify the modelling of non-linear couplings among the Josephson junctions. Our design helped us reveal unusual electric characteristics with effective zero inductance, which is promising for nanoscale magnetic sensing and quantum technologies.

High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjue, S. K. L., E-mail: sjue@lanl.gov; Mariam, F. G.; Merrill, F. E.

2016-01-15

Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the imagemore » plane. Comparison with a series of static calibration images demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.« less

High order magnetic optics for high dynamic range proton radiography at a kinetic energy 800 MeV

DOE PAGES

Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; ...

2016-01-14

Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the protonimaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane.more » Furthermore, comparison with a series of static calibrationimages demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.« less

Agile multicasting based on cascaded χ(2) nonlinearities in a step-chirped periodically poled lithium niobate.

PubMed

Ahlawat, Meenu; Bostani, Ameneh; Tehranchi, Amirhossein; Kashyap, Raman

2013-08-01

We experimentally demonstrate the possibility of agile multicasting for wavelength division multiplexing (WDM) networks, of a single-channel to two and seven channels over the C band, also extendable to S and L bands. This is based on cascaded χ(2) nonlinear mixing processes, namely, second-harmonic generation (SHG)-sum-frequency generation (SFG) and difference-frequency generation (DFG) in a 20-mm-long step-chirped periodically poled lithium niobate crystal, specially designed and fabricated for a 28-nm-wide SH-SF bandwidth centered at around 1.55 μm. The multiple idlers are simultaneously tuned by detuning the pump wavelengths within the broad SH-SF bandwidth. By selectively tuning the pump wavelengths over less than 10 and 6 nm, respectively, multicasting into two and seven idlers is successfully achieved across ~70 WDM channels within the 50 GHz International Telecommunication Union grid spacing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muto, Hideshi, E-mail: guatemalacocoa@gmail.com; Center for Nuclear Study, University of Tokyo, 2-1 Hirosawa, Riken Campus, Wako, Saitama 351-0198; Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198

The light intensity of {sup 6}Li III line spectrum at λ = 516.7 nm was observed during {sup 6}Li{sup 3+} beam tuning at the Hyper-Electron Cyclotron Resonance (ECR) ion source. Separation of ion species of the same charge to mass ratio with an electromagnetic mass analyzer is known to be an exceptionally complex process. However, {sup 6}Li III line intensity observation conducted in this study gives new insights into its simplification of this process. The light intensity of {sup 6}Li III line spectrum from the ECR plasma was found to have a strong correlation with the extracted {sup 6}Li{sup 3+}more » beam intensity from the RIKEN Azimuthal Varying Field cyclotron.« less

A novel low-molecular-mass gelator with a redox active ferrocenyl group: tuning gel formation by oxidation.

PubMed

Liu, Jing; Yan, Junlin; Yuan, Xuanwei; Liu, Kaiqiang; Peng, Junxia; Fang, Yu

2008-02-15

A novel low-molecular-mass gelator containing a redox-active ferrocenyl group, cholesteryl glycinate ferrocenoylamide (CGF), was intentionally designed and prepared. It was demonstrated that the gelator gels 13 out of the 45 solvents tested. Scanning electron microscopy (SEM) measurements revealed that the gelator self-assembled into different supramolecular network structures in different gels. Chemical oxidation of the ferrocenyl residue resulted in phase transition of the gel from gel state to solution state. FTIR and (1)H NMR spectroscopy studies revealed that hydrogen bonding between the gelator molecules in the gel was one of the main driving forces for the formation of the gels.

Externally tuned vibration absorber

DOEpatents

Vincent, Ronald J.

1987-09-22

A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

Directed Energy Technology Overview

DTIC Science & Technology

2011-06-01

with an AR coating, The primary mirror is zerodur on a 9 point mount incorporating a tuned mass damper.. The secondary, tertiary, and coude optics are...beam conditioning back end section: • A beam expander enlarges the beam and shapes it to fill the active area of a deformable mirror • Because of the...enabling technologies that would make a 100-kW SS laser possible (high power optical coatings, high power gain modules, deformable mirror technology