A generalized theoretical framework for the description of spin decoupling in solid-state MAS NMR: Offset effect on decoupling performance.

PubMed

Tan, Kong Ooi; Agarwal, Vipin; Meier, Beat H; Ernst, Matthias

2016-09-07

We present a generalized theoretical framework that allows the approximate but rapid analysis of residual couplings of arbitrary decoupling sequences in solid-state NMR under magic-angle spinning conditions. It is a generalization of the tri-modal Floquet analysis of TPPM decoupling [Scholz et al., J. Chem. Phys. 130, 114510 (2009)] where three characteristic frequencies are used to describe the pulse sequence. Such an approach can be used to describe arbitrary periodic decoupling sequences that differ only in the magnitude of the Fourier coefficients of the interaction-frame transformation. It allows a ∼100 times faster calculation of second-order residual couplings as a function of pulse sequence parameters than full spin-dynamics simulations. By comparing the theoretical calculations with full numerical simulations, we show the potential of the new approach to examine the performance of decoupling sequences. We exemplify the usefulness of this framework by analyzing the performance of commonly used high-power decoupling sequences and low-power decoupling sequences such as amplitude-modulated XiX (AM-XiX) and its super-cycled variant SC-AM-XiX. In addition, the effect of chemical-shift offset is examined for both high- and low-power decoupling sequences. The results show that the cross-terms between the dipolar couplings are the main contributions to the line broadening when offset is present. We also show that the SC-AM-XIX shows a better offset compensation.

(13)C MRS of human brain at 7 Tesla using [2-(13)C]glucose infusion and low power broadband stochastic proton decoupling.

PubMed

Li, Shizhe; An, Li; Yu, Shao; Ferraris Araneta, Maria; Johnson, Christopher S; Wang, Shumin; Shen, Jun

2016-03-01

Carbon-13 ((13)C) MR spectroscopy (MRS) of the human brain at 7 Tesla (T) may pose patient safety issues due to high radiofrequency (RF) power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo (13)C MRS of human brain at 7 T using broadband low RF power proton decoupling. Carboxylic/amide (13)C MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. (13)C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. At 7 T, the peak amplitude of carboxylic/amide (13)C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T (13)C MRS technique used decoupling power and average transmit power of less than 35 watts (W) and 3.6 W, respectively. In vivo (13)C MRS studies of human brain can be performed at 7 T, well below the RF safety threshold, by detecting carboxylic/amide carbons with broadband stochastic proton decoupling. © 2015 Wiley Periodicals, Inc.

13C MRS of Human Brain at 7 Tesla Using [2-13C]Glucose Infusion and Low Power Broadband Stochastic Proton Decoupling

PubMed Central

Li, Shizhe; An, Li; Yu, Shao; Araneta, Maria Ferraris; Johnson, Christopher S.; Wang, Shumin; Shen, Jun

2015-01-01

Purpose 13C magnetic resonance spectroscopy (MRS) of human brain at 7 Tesla (T) may pose patient safety issues due to high RF power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo 13C MRS of human brain at 7 T using broadband low RF power proton decoupling. Methods Carboxylic/amide 13C MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. 13C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. Results At 7 T, the peak amplitude of carboxylic/amide 13C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T 13C MRS technique used decoupling power and average transmit power of less than 35 W and 3.6 W, respectively. Conclusion In vivo 13C MRS studies of human brain can be performed at 7 T well below the RF safety threshold by detecting carboxylic/amide carbons with broadband stochastic proton decoupling. PMID:25917936

Design of the annular suspension and pointing system /ASPS/ through decoupling and pole placement. [for Space Shuttle

NASA Technical Reports Server (NTRS)

Kuo, B. C.; Lin, W. C. W.

1980-01-01

A decoupling and pole-placement technique has been developed for the Annular Suspension and Pointing System (ASPS) of the Space Shuttle which uses bandwidths as performance criteria. The dynamics of the continuous-data ASPS allows the three degrees of freedom to be totally decoupled by state feedback through constant gains, so that the bandwidth of each degree of freedom can be independently specified without interaction. Although it is found that the digital ASPS cannot be completely decoupled, the bandwidth requirements are satisfied by pole placement and a trial-and-error method based on approximate decoupling.

Relationships between the decoupled and coupled transfer functions: Theoretical studies and experimental validation

NASA Astrophysics Data System (ADS)

Wang, Zengwei; Zhu, Ping; Liu, Zhao

2018-01-01

A generalized method for predicting the decoupled transfer functions based on in-situ transfer functions is proposed. The method allows predicting the decoupled transfer functions using coupled transfer functions, without disassembling the system. Two ways to derive relationships between the decoupled and coupled transfer functions are presented. Issues related to immeasurability of coupled transfer functions are also discussed. The proposed method is validated by numerical and experimental case studies.

Is Decoupling GDP Growth from Environmental Impact Possible?

PubMed

Ward, James D; Sutton, Paul C; Werner, Adrian D; Costanza, Robert; Mohr, Steve H; Simmons, Craig T

2016-01-01

The argument that human society can decouple economic growth-defined as growth in Gross Domestic Product (GDP)-from growth in environmental impacts is appealing. If such decoupling is possible, it means that GDP growth is a sustainable societal goal. Here we show that the decoupling concept can be interpreted using an easily understood model of economic growth and environmental impact. The simple model is compared to historical data and modelled projections to demonstrate that growth in GDP ultimately cannot be decoupled from growth in material and energy use. It is therefore misleading to develop growth-oriented policy around the expectation that decoupling is possible. We also note that GDP is increasingly seen as a poor proxy for societal wellbeing. GDP growth is therefore a questionable societal goal. Society can sustainably improve wellbeing, including the wellbeing of its natural assets, but only by discarding GDP growth as the goal in favor of more comprehensive measures of societal wellbeing.

Deep-subwavelength Decoupling for MIMO Antennas in Mobile Handsets with Singular Medium.

PubMed

Xu, Su; Zhang, Ming; Wen, Huailin; Wang, Jun

2017-09-22

Decreasing the mutual coupling between Multi-input Multi-output (MIMO) antenna elements in a mobile handset and achieving a high data rate is a challenging topic as the 5 th -generation (5G) communication age is coming. Conventional decoupling components for MIMO antennas have to be re-designed when the geometries or frequencies of antennas have any adjustment. In this paper, we report a novel metamaterial-based decoupling strategy for MIMO antennas in mobile handsets with wide applicability. The decoupling component is made of subwavelength metal/air layers, which can be treated as singular medium over a broad frequency band. The flexible applicable property of the decoupling strategy is verified with different antennas over different frequency bands with the same metamaterial decoupling element. Finally, 1/100-wavelength 10-dB isolation is demonstrated for a 24-element MIMO antenna in mobile handsets over the frequency band from 4.55 to 4.75 GHz.

Faithful Solid State Optical Memory with Dynamically Decoupled Spin Wave Storage

NASA Astrophysics Data System (ADS)

Lovrić, Marko; Suter, Dieter; Ferrier, Alban; Goldner, Philippe

2013-07-01

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

Faithful solid state optical memory with dynamically decoupled spin wave storage.

PubMed

Lovrić, Marko; Suter, Dieter; Ferrier, Alban; Goldner, Philippe

2013-07-12

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

Decoupling of Solid 4He Layers under the Superfluid Overlayer

NASA Astrophysics Data System (ADS)

Ishibashi, Kenji; Hiraide, Jo; Taniguchi, Junko; Suzuki, Masaru

2018-03-01

It has been reported that in a large oscillation amplitude, the mass decoupling of multilayer 4He films adsorbed on graphite results from the depinning of the second solid atomic layer. This decoupling suddenly vanishes below a certain low temperature TD due to the cancellation of mass decoupling by the superfluid counterflow of the the overylayer. We studied the relaxation of the depinned state at various temperatures, after reduction of oscillation amplitude below TD . It was found that above the superfluid transition temperature the mass decoupling revives with a relaxation time of several 100 s. It strongly supports that the depinned state of the second solid atomic layer remains underneath the superfluid overlayer.

Using lagged dependence to identify (de)coupled surface and subsurface soil moisture values

NASA Astrophysics Data System (ADS)

Carranza, Coleen D. U.; van der Ploeg, Martine J.; Torfs, Paul J. J. F.

2018-04-01

Recent advances in radar remote sensing popularized the mapping of surface soil moisture at different spatial scales. Surface soil moisture measurements are used in combination with hydrological models to determine subsurface soil moisture values. However, variability of soil moisture across the soil column is important for estimating depth-integrated values, as decoupling between surface and subsurface can occur. In this study, we employ new methods to investigate the occurrence of (de)coupling between surface and subsurface soil moisture. Using time series datasets, lagged dependence was incorporated in assessing (de)coupling with the idea that surface soil moisture conditions will be reflected at the subsurface after a certain delay. The main approach involves the application of a distributed-lag nonlinear model (DLNM) to simultaneously represent both the functional relation and the lag structure in the time series. The results of an exploratory analysis using residuals from a fitted loess function serve as a posteriori information to determine (de)coupled values. Both methods allow for a range of (de)coupled soil moisture values to be quantified. Results provide new insights into the decoupled range as its occurrence among the sites investigated is not limited to dry conditions.

Optimal digital dynamical decoupling for general decoherence via Walsh modulation

NASA Astrophysics Data System (ADS)

Qi, Haoyu; Dowling, Jonathan P.; Viola, Lorenza

2017-11-01

We provide a general framework for constructing digital dynamical decoupling sequences based on Walsh modulation—applicable to arbitrary qubit decoherence scenarios. By establishing equivalence between decoupling design based on Walsh functions and on concatenated projections, we identify a family of optimal Walsh sequences, which can be exponentially more efficient, in terms of the required total pulse number, for fixed cancellation order, than known digital sequences based on concatenated design. Optimal sequences for a given cancellation order are highly non-unique—their performance depending sensitively on the control path. We provide an analytic upper bound to the achievable decoupling error and show how sequences within the optimal Walsh family can substantially outperform concatenated decoupling in principle, while respecting realistic timing constraints.

Is Decoupling GDP Growth from Environmental Impact Possible?

PubMed Central

Sutton, Paul C.; Werner, Adrian D.; Costanza, Robert; Mohr, Steve H.; Simmons, Craig T.

2016-01-01

The argument that human society can decouple economic growth—defined as growth in Gross Domestic Product (GDP)—from growth in environmental impacts is appealing. If such decoupling is possible, it means that GDP growth is a sustainable societal goal. Here we show that the decoupling concept can be interpreted using an easily understood model of economic growth and environmental impact. The simple model is compared to historical data and modelled projections to demonstrate that growth in GDP ultimately cannot be decoupled from growth in material and energy use. It is therefore misleading to develop growth-oriented policy around the expectation that decoupling is possible. We also note that GDP is increasingly seen as a poor proxy for societal wellbeing. GDP growth is therefore a questionable societal goal. Society can sustainably improve wellbeing, including the wellbeing of its natural assets, but only by discarding GDP growth as the goal in favor of more comprehensive measures of societal wellbeing. PMID:27741300

Preserving electron spin coherence in solids by optimal dynamical decoupling.

PubMed

Du, Jiangfeng; Rong, Xing; Zhao, Nan; Wang, Ya; Yang, Jiahui; Liu, R B

2009-10-29

To exploit the quantum coherence of electron spins in solids in future technologies such as quantum computing, it is first vital to overcome the problem of spin decoherence due to their coupling to the noisy environment. Dynamical decoupling, which uses stroboscopic spin flips to give an average coupling to the environment that is effectively zero, is a particularly promising strategy for combating decoherence because it can be naturally integrated with other desired functionalities, such as quantum gates. Errors are inevitably introduced in each spin flip, so it is desirable to minimize the number of control pulses used to realize dynamical decoupling having a given level of precision. Such optimal dynamical decoupling sequences have recently been explored. The experimental realization of optimal dynamical decoupling in solid-state systems, however, remains elusive. Here we use pulsed electron paramagnetic resonance to demonstrate experimentally optimal dynamical decoupling for preserving electron spin coherence in irradiated malonic acid crystals at temperatures from 50 K to room temperature. Using a seven-pulse optimal dynamical decoupling sequence, we prolonged the spin coherence time to about 30 mus; it would otherwise be about 0.04 mus without control or 6.2 mus under one-pulse control. By comparing experiments with microscopic theories, we have identified the relevant electron spin decoherence mechanisms in the solid. Optimal dynamical decoupling may be applied to other solid-state systems, such as diamonds with nitrogen-vacancy centres, and so lay the foundation for quantum coherence control of spins in solids at room temperature.

Research on the application of a decoupling algorithm for structure analysis

NASA Technical Reports Server (NTRS)

Denman, E. D.

1980-01-01

The mathematical theory for decoupling mth-order matrix differential equations is presented. It is shown that the decoupling precedure can be developed from the algebraic theory of matrix polynomials. The role of eigenprojectors and latent projectors in the decoupling process is discussed and the mathematical relationships between eigenvalues, eigenvectors, latent roots, and latent vectors are developed. It is shown that the eigenvectors of the companion form of a matrix contains the latent vectors as a subset. The spectral decomposition of a matrix and the application to differential equations is given.

An Inviscid Decoupled Method for the Roe FDS Scheme in the Reacting Gas Path of FUN3D

NASA Technical Reports Server (NTRS)

Thompson, Kyle B.; Gnoffo, Peter A.

2016-01-01

An approach is described to decouple the species continuity equations from the mixture continuity, momentum, and total energy equations for the Roe flux difference splitting scheme. This decoupling simplifies the implicit system, so that the flow solver can be made significantly more efficient, with very little penalty on overall scheme robustness. Most importantly, the computational cost of the point implicit relaxation is shown to scale linearly with the number of species for the decoupled system, whereas the fully coupled approach scales quadratically. Also, the decoupled method significantly reduces the cost in wall time and memory in comparison to the fully coupled approach. This work lays the foundation for development of an efficient adjoint solution procedure for high speed reacting flow.

Proton-decoupled, Overhauser-enhanced, spatially localized carbon-13 spectroscopy in humans.

PubMed

Bottomley, P A; Hardy, C J; Roemer, P B; Mueller, O M

1989-12-01

Spatially localized, natural abundance, carbon (13C) NMR spectroscopy has been combined with proton (1H) decoupling and nuclear Overhauser enhancement to improve 13C sensitivity up to five-fold in the human leg, liver, and heart. Broadhand-decoupled 13C spectra were acquired in 1 s to 17 min with a conventional 1.5-T imaging/spectroscopy system, an auxiliary 1H decoupler, an air-cooled dual-coil coplanar surface probe, and both depth-resolved surface coil spectroscopy (DRESS) and one-dimensional phase-encoding gradient NMR pulse sequences. The surface coil probe comprised circular and figure-eight-shaped coils to eliminate problems with mutual coupling of coils at high decoupling power levels applied during 13C reception. Peak decoupler RF power deposition in tissue was computed numerically from electromagnetic theory assuming a semi-infinite plane of uniform biological conductor. Peak values at the surface were calculated at 4 to 6 W/kg in any gram of tissue for each watt of decoupler power input excluding all coil and cable losses, warning of potential local RF heating problems in these and related experiments. The average power deposition was about 9 mW/kg per watt input, which should present no systemic hazard. At 3 W input, human 13C spectra were decoupled to a depth of about 5 cm while some Overhauser enhancement was sustained up to about 3 cm depth, without ill effect. The observation of glycogen in localized natural abundance 13C spectra of heart and muscle suggests that metabolites in the citric acid cycle should be observable noninvasively using 13C-labeled substrates.

Systematic evaluation of heteronuclear spin decoupling in solid-state NMR at the rotary-resonance conditions in the regime of fast magic-angle spinning

NASA Astrophysics Data System (ADS)

Sharma, Kshama; Madhu, P. K.; Agarwal, Vipin

2016-09-01

The performance of heteronuclear spin decoupling sequences in solid-state NMR severely degrades when the proton radiofrequency (RF) nutation frequencies (ν1) are close to or at multiples of magic-angle spinning (MAS) frequency (νr) that are referred to as rotary-resonance recoupling conditions (ν1 = n · νr). Recently, two schemes, namely, PISSARRO and rCWApA, have been shown to be less affected by the problem of MAS and RF interference, specifically at the n = 2 rotary-resonance recoupling condition, especially in the fast MAS regime. Here, we systematically evaluate the loss in intensity of several heteronuclear spin decoupling sequences at the n = 1, 2 conditions compared to high-power decoupling in the fast-MAS regime. We propose that in the fast-MAS regime (above 40 kHz) the entire discussion about RF and MAS interference can be avoided by using appropriate low-power decoupling sequences which give comparable performance to decoupling sequences with high-power 1H irradiation of ca.195 kHz.

Decoupling Polymer Properties to Elucidate Mechanisms Governing Cell Behavior

PubMed Central

Wang, Xintong; Boire, Timothy C.; Bronikowski, Christine; Zachman, Angela L.; Crowder, Spencer W.

2012-01-01

Determining how a biomaterial interacts with cells (“structure-function relationship”) reflects its eventual clinical applicability. Therefore, a fundamental understanding of how individual material properties modulate cell-biomaterial interactions is pivotal to improving the efficacy and safety of clinically translatable biomaterial systems. However, due to the coupled nature of material properties, their individual effects on cellular responses are difficult to understand. Structure-function relationships can be more clearly understood by the effective decoupling of each individual parameter. In this article, we discuss three basic decoupling strategies: (1) surface modification, (2) cross-linking, and (3) combinatorial approaches (i.e., copolymerization and polymer blending). Relevant examples of coupled material properties are briefly reviewed in each section to highlight the need for improved decoupling methods. This follows with examples of more effective decoupling techniques, mainly from the perspective of three primary classes of synthetic materials: polyesters, polyethylene glycol, and polyacrylamide. Recent strides in decoupling methodologies, especially surface-patterning and combinatorial techniques, offer much promise in further understanding the structure-function relationships that largely govern the success of future advancements in biomaterials, tissue engineering, and drug delivery. PMID:22536977

Resolution enhancement in 13C and 15N magic-angle turning experiments with TPPM decoupling.

PubMed

McGeorge, G; Alderman, D W; Grant, D M

1999-03-01

Many solid-state spectra have been shown to have problems related to the poor proton decoupling of carbon nuclei in methylene groups under conditions of slow magic-angle turning. Two-pulse phase-modulation (TPPM) decoupling during the 2D PHORMAT chemical shift separation experiment is shown to be more effective in comparison to that obtainable at much higher spin rates using conventional CW decoupling. TPPM decoupling can also alleviate similar inadequacies when observing the 15N nucleus, particularly with NH2 groups. This is demonstrated in the 15N resonances of fully labeled l-arginine hydrochloride, where a line narrowing of about a factor of two was observed at moderate rotation rates. This significant advantage was also obtained at turning frequencies as low as 500 Hz. Copyright 1999 Academic Press.

Developmental decoupling of alternative phenotypes: insights from the transcriptomes of horn-polyphenic beetles

PubMed Central

Snell-Rood, Emilie C.; Cash, Amy; Han, Mira V.; Kijimoto, Teiya; Andrews, Justen; Moczek, Armin P.

2010-01-01

Developmental mechanisms play an important role in determining the costs, limits, and evolutionary consequences of phenotypic plasticity. One issue central to these claims is the hypothesis of developmental decoupling, where alternate morphs result from evolutionarily independent developmental pathways. We address this assumption through a microarray study that tests whether differences in gene expression between alternate morphs are as divergent as those between sexes, a classic example of developmental decoupling. We then examine whether genes with morph-biased expression are less conserved than genes with shared expression between morphs, as predicted if developmental decoupling relaxes pleiotropic constraints on divergence. We focus on the developing horns and brains of two species of horned beetles with spectacular sexual- and morph-dimorphism in the expression of horns and fighting behavior. We find that patterns of gene expression were as divergent between morphs as they were between sexes. However, overall patterns of gene expression were also highly correlated across morphs and sexes. Morph-biased genes were more evolutionarily divergent, suggesting a role of relaxed pleiotropic constraints or relaxed selection. Together these results suggest that alternate morphs are to some extent developmentally decoupled, and that this decoupling has significant evolutionary consequences. However, alternative morphs may not be as developmentally decoupled as sometimes assumed and such hypotheses of development should be revisited and refined. PMID:20731717

FRF decoupling of nonlinear systems

NASA Astrophysics Data System (ADS)

Kalaycıoğlu, Taner; Özgüven, H. Nevzat

2018-03-01

Structural decoupling problem, i.e. predicting dynamic behavior of a particular substructure from the knowledge of the dynamics of the coupled structure and the other substructure, has been well investigated for three decades and led to several decoupling methods. In spite of the inherent nonlinearities in a structural system in various forms such as clearances, friction and nonlinear stiffness, all decoupling studies are for linear systems. In this study, decoupling problem for nonlinear systems is addressed for the first time. A method, named as FRF Decoupling Method for Nonlinear Systems (FDM-NS), is proposed for calculating FRFs of a substructure decoupled from a coupled nonlinear structure where nonlinearity can be modeled as a single nonlinear element. Depending on where nonlinear element is, i.e., either in the known or unknown subsystem, or at the connection point, the formulation differs. The method requires relative displacement information between two end points of the nonlinear element, in addition to point and transfer FRFs at some points of the known subsystem. However, it is not necessary to excite the system from the unknown subsystem even when the nonlinear element is in that subsystem. The validation of FDM-NS is demonstrated with two different case studies using nonlinear lumped parameter systems. Finally, a nonlinear experimental test structure is used in order to show the real-life application and accuracy of FDM-NS.

Decoupling in linear time-varying multivariable systems

NASA Technical Reports Server (NTRS)

Sankaran, V.

1973-01-01

The necessary and sufficient conditions for the decoupling of an m-input, m-output, linear time varying dynamical system by state variable feedback is described. The class of feedback matrices which decouple the system are illustrated. Systems which do not satisfy these results are described and systems with disturbances are considered. Some examples are illustrated to clarify the results.

The Fall and Rise of Experiential Construction and Engineering Education: Decoupling and Recoupling Practice and Theory

ERIC Educational Resources Information Center

Forster, Alan Mark; Pilcher, Nick; Tennant, Stuart; Murray, Mike; Craig, Nigel; Copping, Alex

2017-01-01

From the mid-20th C., construction and engineering pedagogy and curricula have moved from long-held traditional experiential apprenticeship approaches to one ostensibly decoupling practice and theory. This paper traces this decoupling and explores modern-day opportunities and challenges for recoupling university education with industry practice.…

Contrasting cloud composition between coupled and decoupled marine boundary layer clouds

NASA Astrophysics Data System (ADS)

Wang, Zhen; Mora Ramirez, Marco; Dadashazar, Hossein; MacDonald, Alex B.; Crosbie, Ewan; Bates, Kelvin H.; Coggon, Matthew M.; Craven, Jill S.; Lynch, Peng; Campbell, James R.; Azadi Aghdam, Mojtaba; Woods, Roy K.; Jonsson, Haflidi; Flagan, Richard C.; Seinfeld, John H.; Sorooshian, Armin

2016-10-01

Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the ocean surface. This study contrasts cloud chemical composition between coupled and decoupled marine stratocumulus clouds for dissolved nonwater substances. Cloud water and droplet residual particle composition were measured in clouds off the California coast during three airborne experiments in July-August of separate years (Eastern Pacific Emitted Aerosol Cloud Experiment 2011, Nucleation in California Experiment 2013, and Biological and Oceanic Atmospheric Study 2015). Decoupled clouds exhibited significantly lower air-equivalent mass concentrations in both cloud water and droplet residual particles, consistent with reduced cloud droplet number concentration and subcloud aerosol (Dp > 100 nm) number concentration, owing to detachment from surface sources. Nonrefractory submicrometer aerosol measurements show that coupled clouds exhibit higher sulfate mass fractions in droplet residual particles, owing to more abundant precursor emissions from the ocean and ships. Consequently, decoupled clouds exhibited higher mass fractions of organics, nitrate, and ammonium in droplet residual particles, owing to effects of long-range transport from more distant sources. Sodium and chloride dominated in terms of air-equivalent concentration in cloud water for coupled clouds, and their mass fractions and concentrations exceeded those in decoupled clouds. Conversely, with the exception of sea-salt constituents (e.g., Cl, Na, Mg, and K), cloud water mass fractions of all species examined were higher in decoupled clouds relative to coupled clouds. Satellite and Navy Aerosol Analysis and Prediction System-based reanalysis data are compared with each other, and the airborne data to conclude that limitations in resolving boundary layer processes in a global model prevent it from accurately quantifying observed differences between coupled and decoupled cloud composition.

Moving-base visual simulation study of decoupled controls during approach and landing of a STOL transport aircraft

NASA Technical Reports Server (NTRS)

Miller, G. K., Jr.; Deal, P. L.

1975-01-01

The simulation employed all six rigid-body degrees of freedom and incorporated aerodynamic characteristics based on wind-tunnel data. The flight instrumentation included a localizer and a flight director which was used to capture and to maintain a two-segment glide slope. A closed-circuit television display of a STOLport provided visual cues during simulations of the approach and landing. The decoupled longitudinal controls used constant prefilter and feedback gains to provide steady-state decoupling of flight-path angle, pitch angle, and forward velocity. The pilots were enthusiastic about the decoupled longitudinal controls and believed that the simulator motion was an aid in evaluating the decoupled controls, although a minimum turbulence level with root-mean-square gust intensity of 0.3 m/sec (1 ft/sec) was required to mask undesirable characteristics of the moving-base simulator.

PI controller design for indirect vector controlled induction motor: A decoupling approach.

PubMed

Jain, Jitendra Kr; Ghosh, Sandip; Maity, Somnath; Dworak, Pawel

2017-09-01

Decoupling of the stator currents is important for smoother torque response of indirect vector controlled induction motors. Typically, feedforward decoupling is used to take care of current coupling that requires exact knowledge of motor parameters, additional circuitry and signal processing. In this paper, a method is proposed to design the regulating proportional-integral gains that minimize coupling without any requirement of the additional decoupler. The variation of the coupling terms for change in load torque is considered as the performance measure. An iterative linear matrix inequality based H ∞ control design approach is used to obtain the controller gains. A comparison between the feedforward and the proposed decoupling schemes is presented through simulation and experimental results. The results show that the proposed scheme is simple yet effective even without additional block or burden on signal processing. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Characterization of heteronuclear decoupling through proton spin dynamics in solid-state nuclear magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

De Paëpe, Gaël; Eléna, Bénédicte; Emsley, Lyndon

2004-08-01

The work presented here aims at understanding the performance of phase modulated heteronuclear decoupling sequences such as Cosine Modulation or Two Pulse Phase Modulation. To that end we provide an analytical description of the intrinsic behavior of Cosine Modulation decoupling with respect to radio-frequency-inhomogeneity and the proton-proton dipolar coupling network. We discover through a Modulation Frame average Hamiltonian analysis that best decoupling is obtained under conditions where the heteronuclear interactions are removed but notably where homonuclear couplings are recoupled at a homonuclear Rotary Resonance (HORROR) condition in the Modulation Frame. These conclusions are supported by extensive experimental investigations, and notably through the introduction of proton nutation experiments to characterize spin dynamics in solids under decoupling conditions. The theoretical framework presented in this paper allows the prediction of the optimum parameters for a given set of experimental conditions.

Improved heteronuclear dipolar decoupling sequences for liquid-crystal NMR

NASA Astrophysics Data System (ADS)

Thakur, Rajendra Singh; Kurur, Narayanan D.; Madhu, P. K.

2007-04-01

Recently we introduced a radiofrequency pulse scheme for heteronuclear dipolar decoupling in solid-state nuclear magnetic resonance under magic-angle spinning [R.S. Thakur, N.D. Kurur, P.K. Madhu, Swept-frequency two-pulse phase modulation for heteronuclear dipolar decoupling in solid-state NMR, Chem. Phys. Lett. 426 (2006) 459-463]. Variants of this sequence, swept-frequency TPPM, employing frequency modulation of different types have been further tested to improve the efficiency of heteronuclear dipolar decoupling. Among these, certain sequences that were found to perform well at lower spinning speeds are demonstrated here on a liquid-crystal sample of MBBA for application in static samples. The new sequences are compared with the standard TPPM and SPINAL schemes and are shown to perform better than them. These modulated schemes perform well at low decoupler radiofrequency power levels and are easy to implement on standard spectrometers.

Investigation of marine stratocumulus under coupled and decoupled conditions over the arm Azores site

NASA Astrophysics Data System (ADS)

Schwantes, Adam Christopher

Stratocumuli are a type of low clouds composed of individual convective elements that together form a continuous layer of clouds. Stratocumuli cover large regions of the Earth's surface, which make them important components in the Earth's radiation budget. Stratocumuli strongly reflect solar shortwave radiation, while weakly affecting outgoing longwave radiation. This leads to a strong radiative cooling effect that affects the Earth's radiation budget. Therefore it is important to investigate the mechanisms that affect the longevity of stratocumuli, so that their impact on the Earth's radiation budget can be fully understood. One mechanism that is currently being studied as influencing the lifetime of such cloud layers is boundary layer/surface coupling. It has been shown than in some regions (i.e. the west coast of South America) stratocumuli tend to break up when the boundary layer is decoupled with the surface, because they are cut off from their moisture source. This study will investigate the macro- and micro-physical properties of stratocumuli when boundary layers are either coupled to or decoupled from the surface. This will help advance understanding of the effects these macro- and micro-physical properties have on the lifetime of stratocumuli under different boundary layer conditions. This study used the Department of Energy Atmospheric Radiation Measurement (DOE ARM) mobile measurements facility (AMF) at the Azores site from June 2009 to December 2010. The measurements that were used include temperature profiles from radiosondes, cloud liquid water path (LWP) retrieved from the Microwave radiometer, and cloud base and top heights derived from W-band ARM Cloud Radar and lidar. Satellite images provided by the NASA Langley Research Center were also used to visually decipher cloud types over the region so that only single-layered stratocumuli cases are used in the study. To differentiate between coupled and decoupled cloud layers, two methods are used. The first method compares cloud base height and lifting condensation level (LCL) for surface air parcels. The second method uses potential temperature profiles to indicate whether a boundary layer is coupled or decoupled from the surface. The results from these two methods were then compared using select cases/samples when both methods classified a sample as coupled or decoupled. In this study, a total of seven coupled or decoupled cases (2-3 days long each) have been selected from the 19 month AMF dataset. Characteristics of the coupled and decoupled cases have been studied to identify similarities and differences. Furthermore, comparison results from this study have shown that there are similarities and differences between drizzling/non-drizzling stratocumulus clouds and decoupled/coupled stratocumulus clouds. Drizzling/decoupled stratocumuli tend to have higher LWP, cloud-droplet effective radius (re), cloud-top height, and cloud thickness values while non-drizzling/coupled stratocumuli have higher cloud-droplet number concentration (Nd) and cloud condensation nuclei concentration (NCCN) values. It was also determined that during daytime hours when stratocumuli are decoupled, they tend to be open cells, while coupled stratocumuli tend to be closed cells. Finally, decoupled nighttime stratocumuli were found to have higher LWPs compared to decoupled daytime stratocumuli, which resulted in the significant amount of heavy drizzle events occurring at night.

Evaluating Decoupling Process in OECD Countries: Case Study of Turkey

NASA Astrophysics Data System (ADS)

An, Nazan; Şengün Ucal, Meltem; Kurnaz, M. Levent

2017-04-01

Climate change is at the top of the present and future problems facing humanity. Climate change is now largely attributed to human activities and economic activities are the source of human activities that cause climate change by creating pressure on the environment. Providing the sustainability of resources for the future seems possible by reducing the pressure of these economic activities on the environment. Given the increasing population pressure and growth-focused economies, it is possible to say that achieving decoupling is not so easy on a global basis. It is known that there are some problems in developing countries especially in terms of accessing reliable data in transition and implementation process of decoupling. Developed countries' decoupling practices and proper calculation methods can also be a guide for developing countries. In this study, we tried to calculate the comparative decoupling index for OECD countries and Turkey in terms of data suitability, and we showed the differences between them. We tried to indicate the level of decoupling (weak, stable, strong) for each country. We think that the comparison of Turkey can be an example in terms of developing countries. Acknowledgement: This research has been supported by Bogazici University Research Fund Grant Number 12220.

Resolution enhancement using a new multiple-pulse decoupling sequence for quadrupolar nuclei.

PubMed

Delevoye, L; Trébosc, J; Gan, Z; Montagne, L; Amoureux, J-P

2007-05-01

A new decoupling composite pulse sequence is proposed to remove the broadening on spin S=1/2 magic-angle spinning (MAS) spectra arising from the scalar coupling with a quadrupolar nucleus I. It is illustrated on the (31)P spectrum of an aluminophosphate, AlPO(4)-14, which is broadened by the presence of (27)Al/(31)P scalar couplings. The multiple-pulse (MP) sequence has the advantage over the continuous wave (CW) irradiation to efficiently annul the scalar dephasing without reintroducing the dipolar interaction. The MP decoupling sequence is first described in a rotor-synchronised version (RS-MP) where one parameter only needs to be adjusted. It clearly avoids the dipolar recoupling in order to achieve a better resolution than using the CW sequence. In a second improved version, the MP sequence is experimentally studied in the vicinity of the perfect rotor-synchronised conditions. The linewidth at half maximum (FWHM) of 65 Hz using (27)Al CW decoupling decreases to 48 Hz with RS-MP decoupling and to 30 Hz with rotor-asynchronised MP (RA-MP) decoupling. The main phenomena are explained using both experimental results and numerical simulations.

Decoupling of a tight-fit transceiver phased array for human brain imaging at 9.4T: Loop overlapping rediscovered.

PubMed

Avdievich, Nikolai I; Giapitzakis, Ioannis-Angelos; Pfrommer, Andreas; Henning, Anke

2018-02-01

To improve the decoupling of a transceiver human head phased array at ultra-high fields (UHF, ≥ 7T) and to optimize its transmit (Tx) and receive (Rx) performance, a single-row eight-element (1 × 8) tight-fit transceiver overlapped loop array was developed and constructed. Overlapping the loops increases the RF field penetration depth but can compromise decoupling by generating substantial mutual resistance. Based on analytical modeling, we optimized the loop geometry and relative positioning to simultaneously minimize the resistive and inductive coupling and constructed a 9.4T eight-loop transceiver head phased array decoupled entirely by overlapping loops. We demonstrated that both the magnetic and electric coupling between adjacent loops is compensated at the same time by overlapping and nearly perfect decoupling (below -30 dB) can be obtained without additional decoupling strategies. Tx-efficiency and SNR of the overlapped array outperformed that of a common UHF gapped array of similar dimensions. Parallel Rx-performance was also not compromised due to overlapping the loops. As a proof of concept we developed and constructed a 9.4T (400 MHz) overlapped transceiver head array based on results of the analytical modeling. We demonstrated that at UHF overlapping loops not only provides excellent decoupling but also improves both Tx- and Rx-performance. Magn Reson Med 79:1200-1211, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Contrasting Cloud Composition Between Coupled and Decoupled Marine Boundary Layer Clouds

NASA Astrophysics Data System (ADS)

WANG, Z.; Mora, M.; Dadashazar, H.; MacDonald, A.; Crosbie, E.; Bates, K. H.; Coggon, M. M.; Craven, J. S.; Xian, P.; Campbell, J. R.; AzadiAghdam, M.; Woods, R. K.; Jonsson, H.; Flagan, R. C.; Seinfeld, J.; Sorooshian, A.

2016-12-01

Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the ocean surface. This study contrasts cloud chemical composition between coupled and decoupled marine stratocumulus clouds. Cloud water and droplet residual particle composition were measured in clouds off the California coast during three airborne experiments in July-August of separate years (E-PEACE 2011, NiCE 2013, BOAS 2015). Decoupled clouds exhibited significantly lower overall mass concentrations in both cloud water and droplet residual particles, consistent with reduced cloud droplet number concentration and sub-cloud aerosol (Dp > 100 nm) number concentration, owing to detachment from surface sources. Non-refractory sub-micrometer aerosol measurements show that coupled clouds exhibit higher sulfate mass fractions in droplet residual particles, owing to more abundant precursor emissions from the ocean and ships. Consequently, decoupled clouds exhibited higher mass fractions of organics, nitrate, and ammonium in droplet residual particles, owing to effects of long-range transport from more distant sources. Total cloud water mass concentration in coupled clouds was dominated by sodium and chloride, and their mass fractions and concentrations exceeded those in decoupled clouds. Conversely, with the exception of sea salt constituents (e.g., Cl, Na, Mg, K), cloud water mass fractions of all species examined were higher in decoupled clouds relative to coupled clouds. These results suggest that an important variable is the extent to which clouds are coupled to the surface layer when interpreting microphysical data relevant to clouds and aerosol particles.

Efficient heteronuclear decoupling in MAS solid-state NMR using non-rotor-synchronized rCW irradiation.

PubMed

Equbal, Asif; Paul, Subhradip; Mithu, Venus Singh; Madhu, P K; Nielsen, Niels Chr

2014-09-01

We present new non-rotor-synchronized variants of the recently introduced refocused continuous wave (rCW) heteronuclear decoupling method significantly improving the performance relative to the original rotor-synchronized variants. Under non-rotor-synchronized conditions the rCW decoupling sequences provide more efficient decoupling, are easier to setup, and prove more robust towards experimental parameters such as radio frequency (rf) field amplitude and spinning frequency. This is demonstrated through numerical simulations substantiated with experimental results under different sample spinning and rf field amplitude conditions for powder samples of U-(13)C-glycine and U-(13)C-L-histidine·HCl·H2O. Copyright © 2014 Elsevier Inc. All rights reserved.

Decoupled Modulation Control

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

Wang, Shaobu; Huang, Renke; Huang, Zhenyu

The objective of this research work is to develop decoupled modulation control methods for damping inter-area oscillations with low frequencies, so the damping control can be more effective and easier to design with less interference among different oscillation modes in the power system. A signal-decoupling algorithm was developed that can enable separation of multiple oscillation frequency contents and extraction of a “pure” oscillation frequency mode that are fed into Power System Stabilizers (PSSs) as the modulation input signals. As a result, instead of introducing interferences between different oscillation modes from the traditional approaches, the output of the new PSS modulationmore » control signal mainly affects only one oscillation mode of interest. The new decoupled modulation damping control algorithm has been successfully developed and tested on the standard IEEE 4-machine 2-area test system and a minniWECC system. The results are compared against traditional modulation controls, which demonstrates the validity and effectiveness of the newly-developed decoupled modulation damping control algorithm.« less

Noise-resilient quantum evolution steered by dynamical decoupling

PubMed Central

Liu, Gang-Qin; Po, Hoi Chun; Du, Jiangfeng; Liu, Ren-Bao; Pan, Xin-Yu

2013-01-01

Realistic quantum computing is subject to noise. Therefore, an important frontier in quantum computing is to implement noise-resilient quantum control over qubits. At the same time, dynamical decoupling can protect the coherence of qubits. Here we demonstrate non-trivial quantum evolution steered by dynamical decoupling control, which simultaneously suppresses noise effects. We design and implement a self-protected controlled-NOT gate on the electron spin of a nitrogen-vacancy centre and a nearby carbon-13 nuclear spin in diamond at room temperature, by employing an engineered dynamical decoupling control on the electron spin. Final state fidelity of 0.91(1) is observed in preparation of a Bell state using the gate. At the same time, the qubit coherence time is elongated at least 30 fold. The design scheme does not require the dynamical decoupling control to commute with the qubit interaction and therefore works for general qubit systems. This work marks a step towards implementing realistic quantum computing systems. PMID:23912335

Decoupling of ion conductivity from segmental dynamics in oligomeric ethylene oxide functionalized oxanorbornene dicarboximide homopolymers

DOE PAGES

Adams, Marisa; Richmond, Victoria; Smith, Douglas; ...

2017-03-24

Here, in order to design more effective solid polymer electrolytes, it is important to decouple ion conductivityfrom polymer segmental motion. To that end, novel polymers based on oxanorbornene dicarboximidemonomers with varying lengths of oligomeric ethylene oxide side chains have been synthesized usingring opening metathesis polymerization. These unique polymers have a fairly rigid and bulky backboneand were used to investigate the decoupling of ion motion from polymer segmental dynamics. Ionconductivity was measured using broadband dielectric spectroscopy for varying levels of added lithiumsalt. The conductivity data demonstrate six to seven orders of separation in timescale of ion conductivityfrom polymer segmental motion formore » polymers with shorter ethylene oxide side chains. However,commensurate changes in the glass transition temperatures T g reduce the effect of decoupling in ionconductivity and lead to lower conductivity at ambient conditions. These results suggest that both anincrease in decoupling and a reduction in T g might be required to develop solid polymer electrolytes withhigh ion conductivity at room temperature.« less

Human impacts decouple a fundamental ecological relationship-The positive association between host diversity and parasite diversity.

PubMed

Wood, Chelsea L; Zgliczynski, Brian J; Haupt, Alison J; Guerra, Ana Sofía; Micheli, Fiorenza; Sandin, Stuart A

2018-05-20

Human impacts on ecosystems can decouple the fundamental ecological relationships that create patterns of diversity in free-living species. Despite the abundance, ubiquity, and ecological importance of parasites, it is unknown whether the same decoupling effects occur for parasitic species. We investigated the influence of fishing on the relationship between host diversity and parasite diversity for parasites of coral reef fishes on three fished and three unfished islands in the central equatorial Pacific. Fishing was associated with a shallowing of the positive host-diversity-parasite-diversity relationship. This occurred primarily through negative impacts of fishing on the presence of complex life-cycle parasites, which created a biologically impoverished parasite fauna of directly transmitted parasites resilient to changes in host biodiversity. Parasite diversity appears to be decoupled from host diversity by fishing impacts in this coral reef ecosystem, which suggests that such decoupling might also occur for parasites in other ecosystems affected by environmental change. © 2018 John Wiley & Sons Ltd.

Residual fluctuations in the matter and radiation distribution after the decoupling epoch. [of early universe

NASA Technical Reports Server (NTRS)

Silk, J.; Wilson, M. L.

1980-01-01

The residual spectra of matter and radiation fluctuations in the early universe are investigated, and the evolution of primordial adiabatic and isothermal fluctuations through the decoupling epoch is studied. Amplification of adiabatic density fluctuations during decoupling, or velocity 'overshoot', is largely suppressed by Compton drag. Consequently, the amplitude of density fluctuations entering the horizon prior to decoupling is larger than hitherto assumed in the adiabatic theory. Damping of primordial adiabatic density fluctuations by an order of magnitude occurs on mass-scales of 3 x 10 to the 13th solar masses (Omega = 1) or 10 to the 14th solar masses (Omega = 0.2). Comparison of the residual radiation fluctuations with observational limits indicates that the adiabatic theory is only acceptable if re-ionization of the intergalactic medium results in additional scattering of the radiation after decoupling. Primordial isothermal fluctuations are found to yield radiation fluctuations which are insensitive to the assumed spectrum and lie a factor of about 5 below current limits

Noise-resilient quantum evolution steered by dynamical decoupling.

PubMed

Liu, Gang-Qin; Po, Hoi Chun; Du, Jiangfeng; Liu, Ren-Bao; Pan, Xin-Yu

2013-01-01

Realistic quantum computing is subject to noise. Therefore, an important frontier in quantum computing is to implement noise-resilient quantum control over qubits. At the same time, dynamical decoupling can protect the coherence of qubits. Here we demonstrate non-trivial quantum evolution steered by dynamical decoupling control, which simultaneously suppresses noise effects. We design and implement a self-protected controlled-NOT gate on the electron spin of a nitrogen-vacancy centre and a nearby carbon-13 nuclear spin in diamond at room temperature, by employing an engineered dynamical decoupling control on the electron spin. Final state fidelity of 0.91(1) is observed in preparation of a Bell state using the gate. At the same time, the qubit coherence time is elongated at least 30 fold. The design scheme does not require the dynamical decoupling control to commute with the qubit interaction and therefore works for general qubit systems. This work marks a step towards implementing realistic quantum computing systems.

A Comparison of Methods for Decoupling Tongue and Lower Lip from Jaw Movements in 3D Articulography

ERIC Educational Resources Information Center

Henriques, Rafael Neto; van Lieshout, Pascal

2013-01-01

Purpose: One popular method to study the motion of oral articulators is 3D electromagnetic articulography. For many studies, it is important to use an algorithm to decouple the motion of the tongue and the lower lip from the motion of the mandible. In this article, the authors describe and compare 4 methods for decoupling jaw motion by using 3D…

Mass-transport deposits controlling fault propagation, reactivation and structural decoupling on continental margins (Espírito Santo Basin, SE Brazil)

NASA Astrophysics Data System (ADS)

Omosanya, Kamal'deen O.; Alves, Tiago M.

2014-07-01

This work uses high-quality 3D seismic data to assess the importance of mass-transport deposits (MTDs) as markers of fault propagation. We mapped three distinct MTDs and several fault families on the continental slope of Espírito Santo, SE Brazil. Fault mapping was based on seismic attributes such as seismic coherence and structural smoothing, and was further completed using ant tracking algorithms. Genetically related fault families were analysed in terms of their throw-depth (t-z) and throw-distance (t-x) gradient curves. A key result in this paper is that vertical fault propagation can be hindered by MTDs, as demonstrated for Eocene to Early Miocene faults in parts of the study area. Throw-depth variations in faults affected by MTDs are associated with: a) lithologic controls resulting from the presence of MTDs, b) local fault segmentation and c) reactivation by dip linkage. Based on their orientation and degree of interaction with MTDs, interpreted faults can be classified as decoupled and non-decoupled. Importantly, faults decoupled by MTDs have quasi-elliptical t-x profiles and show smaller cumulative throw values and fault propagation rates when compared to their non-decoupled counterparts. Recurrent MTDs can therefore be used as markers to estimate structural decoupling between distinct fault families.

Pupillometric evidence for the decoupling of attention from perceptual input during offline thought.

PubMed

Smallwood, Jonathan; Brown, Kevin S; Tipper, Christine; Giesbrecht, Barry; Franklin, Michael S; Mrazek, Michael D; Carlson, Jean M; Schooler, Jonathan W

2011-03-25

Accumulating evidence suggests that the brain can efficiently process both external and internal information. The processing of internal information is a distinct "offline" cognitive mode that requires not only spontaneously generated mental activity; it has also been hypothesized to require a decoupling of attention from perception in order to separate competing streams of internal and external information. This process of decoupling is potentially adaptive because it could prevent unimportant external events from disrupting an internal train of thought. Here, we use measurements of pupil diameter (PD) to provide concrete evidence for the role of decoupling during spontaneous cognitive activity. First, during periods conducive to offline thought but not during periods of task focus, PD exhibited spontaneous activity decoupled from task events. Second, periods requiring external task focus were characterized by large task evoked changes in PD; in contrast, encoding failures were preceded by episodes of high spontaneous baseline PD activity. Finally, high spontaneous PD activity also occurred prior to only the slowest 20% of correct responses, suggesting high baseline PD indexes a distinct mode of cognitive functioning. Together, these data are consistent with the decoupling hypothesis, which suggests that the capacity for spontaneous cognitive activity depends upon minimizing disruptions from the external world.

Erosion and landscape development decouple strontium and sulfur in the transition to dominance by atmospheric inputs

USGS Publications Warehouse

Bern, C.R.; Porder, S.; Townsend, A.R.

2007-01-01

Weathering and leaching can progressively deplete the pools of soluble, rock-derived elements in soils and ecosystems over millennial time-scales, such that productivity increasingly relies on inputs from atmospheric deposition. This transition has been explored using strontium isotopes, which have been widely assumed to be a proxy for the provenance of other rock-derived elements. We compared rock versus atmospheric proportions of strontium to those for sulfur, a plant macronutrient, at several tropical forest sites in Hawaii and Costa Rica. Isotopic analyses reveal that sulfur is often decoupled from strontium in the transition to atmospheric dependence. Decoupling is likely the result of differences in chemical factors such as atmospheric input rates, mobility in the soil environment, and mineral weathering susceptibility. Strontium and sulfur decoupling appears to be accentuated by the physical process of erosion. Erosion rates are presumed to be high on the Osa Peninsula of Costa Rica, where the recent onset of rapid tectonic uplift has placed the landscape in a transient state. Decoupling is strong there, as erosion has rejuvenated the supply of rock-derived strontium but not sulfur. The landscape response to changes in tectonic uplift on the Osa Peninsula has produced decoupling at the landscape scale. Decoupling is more variable along a Hawaiian catena, presumably due to smaller scale variations in erosion rates and their influence on rejuvenation of rock-strontium inputs. These results illustrate how chemical and physical processes can interact to produce contrasting origins for different nutrient elements in soils and the ecosystems they support. ?? 2007 Elsevier B.V. All rights reserved.

Investigation of the marine boundary layer cloud and CCN properties under coupled and decoupled conditions over the Azores

DOE PAGES

Dong, Xiquan; Schwantes, Adam C.; Xi, Baike; ...

2015-06-10

Here, six coupled and decoupled marine boundary layer (MBL) clouds were chosen from the 19 month Atmospheric Radiation Measurement Mobile Facility data set over the Azores. Thresholds of liquid water potential temperature difference Δθ L < 0.5 K (>0.5 K) and total water mixing ratio difference Δq t < 0.5 g/kg (>0.5 g/kg) below the cloud base were used for selecting the coupled (decoupled) cases. A schematic diagram was given to demonstrate the coupled and decoupled MBL vertical structures and how they associate with nondrizzle, virga, and rain drizzle events. Out of a total of 2676 5 min samples, 34.5%more » were classified as coupled and 65.5% as decoupled, 36.2% as nondrizzle and 63.8% as drizzle (47.7% as virga and 16.1% as rain), and 33.4% as daytime and 66.6% as nighttime. The decoupled cloud layer is deeper (0.406 km) than coupled cloud layer (0.304 km), and its liquid water path and cloud droplet effective radius (r e) values (122.1 gm -2 and 13.0 µm) are higher than coupled ones (83.7 gm -2 and 10.4 µm). Conversely, decoupled stratocumuli have lower cloud droplet number concentration (N d) and surface cloud condensation nucleus (CCN) concentration (N CCN) (74.5 cm -3 and 150.9 cm -3) than coupled stratocumuli (111.7 cm -3 and 216.4 cm -3). The linear regressions between r e and N d with N CCN have demonstrated that coupled r e and N d strongly depend on N CCN and have higher correlations (-0.56 and 0.59) with N CCN than decoupled results (-0.14 and 0.25). The MBL cloud properties under nondrizzle and virga drizzle conditions are similar to each other but significantly different to those of rain drizzle.« less

Improving the resolution in proton-detected through-space heteronuclear multiple quantum correlation NMR spectroscopy.

PubMed

Shen, Ming; Trébosc, J; Lafon, O; Pourpoint, F; Hu, Bingwen; Chen, Qun; Amoureux, J-P

2014-08-01

Connectivities and proximities between protons and low-gamma nuclei can be probed in solid-state NMR spectroscopy using two-dimensional (2D) proton-detected heteronuclear correlation, through Heteronuclear Multiple Quantum Correlation (HMQC) pulse sequence. The indirect detection via protons dramatically enhances the sensitivity. However, the spectra are often broadened along the indirect F1 dimension by the decay of heteronuclear multiple-quantum coherences under the strong (1)H-(1)H dipolar couplings. This work presents a systematic comparison of the performances of various decoupling schemes during the indirect t1 evolution period of dipolar-mediated HMQC (D-HMQC) experiment. We demonstrate that (1)H-(1)H dipolar decoupling sequences during t1, such as symmetry-based schemes, phase-modulated Lee-Goldburg (PMLG) and Decoupling Using Mind-Boggling Optimization (DUMBO), provide better resolution than continuous wave (1)H irradiation. We also report that high resolution requires the preservation of (1)H isotropic chemical shifts during the decoupling sequences. When observing indirectly broad spectra presenting numerous spinning sidebands, the D-HMQC sequence must be fully rotor-synchronized owing to the rotor-synchronized indirect sampling and dipolar recoupling sequence employed. In this case, we propose a solution to reduce artefact sidebands caused by the modulation of window delays before and after the decoupling application during the t1 period. Moreover, we show that (1)H-(1)H dipolar decoupling sequence using Smooth Amplitude Modulation (SAM) minimizes the t1-noise. The performances of the various decoupling schemes are assessed via numerical simulations and compared to 2D (1)H-{(13)C} D-HMQC experiments on [U-(13)C]-L-histidine⋅HCl⋅H2O at various magnetic fields and Magic Angle spinning (MAS) frequencies. Great resolution and sensitivity enhancements resulting from decoupling during t1 period enable the detection of heteronuclear correlation between aliphatic protons and ammonium (14)N sites in L-histidine⋅HCl⋅H2O. Copyright © 2014 Elsevier Inc. All rights reserved.

Quantum Liouville theory and BTZ black hole entropy

NASA Astrophysics Data System (ADS)

Chen, Yujun

In this thesis I give an explicit conformal field theory description of (2+1)-dimensional BTZ black hole entropy. In the boundary Liouville field theory I investigate the reducible Verma modules in the elliptic sector, which correspond to certain irreducible representations of the quantum algebra Uq(sl2) ⊙ Uq̂(sl2). I show that there are states that decouple from these reducible Verma modules in a similar fashion to the decoupling of null states in minimal models. Because of the nonstandard form of the Ward identity for the two-point correlation functions in quantum Liouville field theory, these decoupling states have positive-definite norms. The unitary representations built on these decoupling states give the Bekenstein-Hawking entropy of the BTZ black hole.

Probing neutrino physics with a self-consistent treatment of the weak decoupling, nucleosynthesis, and photon decoupling epochs

DOE PAGES

Grohs, E.; Fuller, George M.; Kishimoto, Chad T.; ...

2015-05-11

In this study, we show that a self-consistent and coupled treatment of the weak decoupling, big bang nucleosynthesis, and photon decoupling epochs can be used to provide new insights and constraints on neutrino sector physics from high-precision measurements of light element abundances and Cosmic Microwave Background observables. Implications of beyond-standard-model physics in cosmology, especially within the neutrino sector, are assessed by comparing predictions against five observables: the baryon energy density, helium abundance, deuterium abundance, effective number of neutrinos, and sum of the light neutrino mass eigenstates. We give examples for constraints on dark radiation, neutrino rest mass, lepton numbers, andmore » scenarios for light and heavy sterile neutrinos.« less

One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation.

PubMed

Brádler, Kamil; Adami, Christoph

2016-03-11

One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum.

Decoupling analysis for a powertrain mounting system with a combination of hydraulic mounts

NASA Astrophysics Data System (ADS)

Hu, Jinfang; Chen, Wuwei; Huang, He

2013-07-01

The existing torque roll axis(TRA) decoupling theories for a powertrain mounting system assume that the stiffness and viscous damping properties are constant. However, real-life mounts exhibit considerable spectrally varying stiffness and damping characteristics, and the influence of the spectrally-varying properties of the hydraulic mounts on the powertrain system cannot be ignored. To overcome the deficiency, an analytical quasi-linear model of the hydraulic mount and the coupled properties of the powertrain and hydraulic mounts system are formulated. The influence of the hydraulic mounts on the TRA decoupling of a powertrain system is analytically examined in terms of eigensolutions, frequency, and impulse responses, and then a new analytical axiom is proposed based on the TRA decoupling indices. With the experimental setup of a fixed decoupler hydraulic mount in the context of non-resonant dynamic stiffness testing procedure, the quasi-linear model of the hydraulic mount is verified by comparing the predictions with the measurement. And the quasi-linear formulation of the coupled system is also verified by comparing the frequency responses with the numerical results obtained by the direct inversion method. Finally, the mounting system with a combination of hydraulic mounts is redesigned in terms of the stiffness, damping and mount locations by satisfying the new axiom. The frequency and time domain results of the redesigned system demonstrate that the torque roll axis of the redesigned powertrain mounting system is indeed decoupled in the presence of hydraulic mounts (given oscillating torque or impulsive torque excitation). The proposed research provides an important basis and method for the research on a powertrain system with spectrally-varying mount properties, especially for the TRA decoupling.

Virtual decoupling flight control via real-time trajectory synthesis and tracking

NASA Astrophysics Data System (ADS)

Zhang, Xuefu

The production of the General Aviation industry has declined in the past 25 years. Ironically, however, the increasing demand for air travel as a fast, safe, and high-quality mode of transportation has been far from satisfied. Addressing this demand shortfall with personal air transportation necessitates advanced systems for navigation, guidance, control, flight management, and flight traffic control. Among them, an effective decoupling flight control system will not only improve flight quality, safety, and simplicity, and increase air space usage, but also reduce expenses on pilot initial and current training, and thus expand the current market and explore new markets. Because of the formidable difficulties encountered in the actual decoupling of non-linear, time-variant, and highly coupled flight control systems through traditional approaches, a new approach, which essentially converts the decoupling problem into a real-time trajectory synthesis and tracking problem, is employed. Then, the converted problem is solved and a virtual decoupling effect is achieved. In this approach, a trajectory in inertial space can be predefined and dynamically modified based on the flight mission and the pilot's commands. A feedforward-feedback control architecture is constructed to guide the airplane along the trajectory as precisely as possible. Through this approach, the pilot has much simpler, virtually decoupled control of the airplane in terms of speed, flight path angle and horizontal radius of curvature. To verify and evaluate this approach, extensive computer simulation is performed. A great deal of test cases are designed for the flight control under different flight conditions. The simulation results show that our decoupling strategy is satisfactory and promising, and therefore the research can serve as a consolidated foundation for future practical applications.

Aerothermodynamic Design Sensitivities for a Reacting Gas Flow Solver on an Unstructured Mesh Using a Discrete Adjoint Formulation

NASA Astrophysics Data System (ADS)

Thompson, Kyle Bonner

An algorithm is described to efficiently compute aerothermodynamic design sensitivities using a decoupled variable set. In a conventional approach to computing design sensitivities for reacting flows, the species continuity equations are fully coupled to the conservation laws for momentum and energy. In this algorithm, the species continuity equations are solved separately from the mixture continuity, momentum, and total energy equations. This decoupling simplifies the implicit system, so that the flow solver can be made significantly more efficient, with very little penalty on overall scheme robustness. Most importantly, the computational cost of the point implicit relaxation is shown to scale linearly with the number of species for the decoupled system, whereas the fully coupled approach scales quadratically. Also, the decoupled method significantly reduces the cost in wall time and memory in comparison to the fully coupled approach. This decoupled approach for computing design sensitivities with the adjoint system is demonstrated for inviscid flow in chemical non-equilibrium around a re-entry vehicle with a retro-firing annular nozzle. The sensitivities of the surface temperature and mass flow rate through the nozzle plenum are computed with respect to plenum conditions and verified against sensitivities computed using a complex-variable finite-difference approach. The decoupled scheme significantly reduces the computational time and memory required to complete the optimization, making this an attractive method for high-fidelity design of hypersonic vehicles.

On the decoupling of relaxation modes in a molecular liquid caused by isothermal introduction of 2 nm structural inhomogeneities.

PubMed

Ueno, Kazuhide; Angell, C Austen

2011-12-08

To support a new interpretation of the origin of the dynamic heterogeneity observed pervasively in fragile liquids as they approach their glass transition temperatures T(g), we demonstrate that the introduction of ~2 nm structural inhomogeneities into a homogeneous glass former leads to a decoupling of diffusion from viscosity similar to that observed during the cooling of orthoterphenyl (OTP) below T(A,) where Arrhenius behavior is lost. Further, the decoupling effect grows stronger as temperature decreases (and viscosity increases). The liquid is cresol, and the ~2 nm inhomogeneities are cresol-soluble asymmetric derivatized tetrasiloxy-based (polyhedral oligomeric silsesquioxane (POSS)) molecules. The decoupling is the phenomenon predicted by Onsager in discussing the approach to a liquid-liquid phase separation with decreasing temperature. In the present case the observations support the notion of a polyamorphic transition in fragile liquids that is hidden below the glass transition. A similar decoupling can be expected as a globular protein is dissolved in dilute aqueous solutions or in protic ionic liquids. © 2011 American Chemical Society

Fast Dynamical Decoupling of the Mølmer-Sørensen Entangling Gate.

PubMed

Manovitz, Tom; Rotem, Amit; Shaniv, Ravid; Cohen, Itsik; Shapira, Yotam; Akerman, Nitzan; Retzker, Alex; Ozeri, Roee

2017-12-01

Engineering entanglement between quantum systems often involves coupling through a bosonic mediator, which should be disentangled from the systems at the operation's end. The quality of such an operation is generally limited by environmental and control noise. One of the prime techniques for suppressing noise is by dynamical decoupling, where one actively applies pulses at a rate that is faster than the typical time scale of the noise. However, for boson-mediated gates, current dynamical decoupling schemes require executing the pulses only when the boson and the quantum systems are disentangled. This restriction implies an increase of the gate time by a factor of sqrt[N], with N being the number of pulses applied. Here we propose and realize a method that enables dynamical decoupling in a boson-mediated system where the pulses can be applied while spin-boson entanglement persists, resulting in an increase in time that is at most a factor of π/2, independently of the number of pulses applied. We experimentally demonstrate the robustness of our entangling gate with fast dynamical decoupling to σ_{z} noise using ions in a Paul trap.

Proton decoupling and recoupling under double-nutation irradiation in solid-state NMR

NASA Astrophysics Data System (ADS)

Takeda, Kazuyuki; Wakisaka, Asato; Takegoshi, K.

2014-12-01

The effect of 1H decoupling in magic-angle spinning solid-state NMR is studied under radiofrequency irradiation causing simultaneous nutations around a pair of orthogonal axes. Double-nutation with an arbitrary pair of nutation frequencies is implemented through modulation of the amplitude, phase, and frequency of the transmitting pulses. Similarity and difference of double-nutation decoupling and two-pulse phase-modulation decoupling schemes [A. E. Bennett, C. M. Rienstra, M. Auger, K. V. Lakshmi, and R. G. Griffin, J. Chem. Phys. 103, 6951-6958 (1995) and I. Scholz, P. Hodgkinson, B. H. Meier, and M. Ernst, J. Chem. Phys. 130, 114510 (2009)] are discussed. The structure of recoupling bands caused by interference of the 1H spin nutation with sample spinning is studied by both experiments and numerical simulations.

Decoupling capabilities of split-loop resonator structure for 7 Tesla MRI surface array coils

NASA Astrophysics Data System (ADS)

Hurshkainen, A.; Kurdjumov, S.; Simovski, C.; Glybovski, S.; Melchakova, I.; van den Berg, C. A. T.; Raaijmakers, A.; Belov, P.

2017-09-01

In this work we studied electromagnetic properties of one-dimentional periodic structures composed of split-loop res-onators (SLRs) and investigated their capabilities in decoupling of two dipole antennas for full-body magnetic resonance imaging (MRI). Two different finite structures comprising a single-SLR and a double-SLR constitutive elements were studied. Numerical simulations of the structures were performed to evaluate their decoupling capabilities. As it was demonstrated two dipole antennas equipped with either a single or a double-SLR structure exhibit high isolation even for an electrically short distance between the dipoles. Double-SLR structure while dramatically improving isolation of the dipoles keeps the field created by each of the decoupled dipoles comparable with one of a single dipole inside the target area.

Options for decoupling economic growth from water use and water pollution: A report of the Water Working Group of the International Resource Panel Options for decoupling economic growth from water use and water pollution

USDA-ARS?s Scientific Manuscript database

Global trends have pointed to a relative decoupling of water – that is, the rate of water resource use is increasing at a rate slower than that of economic growth. Despite this progress at the global level, it is projected that by 2030 there will be a 40% gap between water supply and water demand if...

Subduction zone decoupling/retreat modeling explains south Tibet (Xigaze) and other supra-subduction zone ophiolites and their UHP mineral phases

NASA Astrophysics Data System (ADS)

Butler, Jared P.; Beaumont, Christopher

2017-04-01

The plate tectonic setting in which proto-ophiolite 'oceanic' lithosphere is created remains controversial with a number of environments suggested. Recent opinions tend to coalesce around supra-subduction zone (SSZ) forearc extension, with a popular conceptual model in which the proto-ophiolite forms during foundering of oceanic lithosphere at the time of spontaneous or induced onset of subduction. This mechanism is favored in intra-oceanic settings where the subducting lithosphere is old and the upper plate is young and thin. We investigate an alternative mechanism; namely, decoupling of the subducting oceanic lithosphere in the forearc of an active continental margin, followed by subduction zone (trench) retreat and creation of a forearc oceanic rift basin, containing proto-ophiolite lithosphere, between the continental margin and the retreating subduction zone. A template of 2D numerical model experiments examines the trade-off between strength of viscous coupling in the lithospheric subduction channel and net slab pull of the subducting lithosphere. Three tectonic styles are observed: 1) C, continuous subduction without forearc decoupling; 2) R, forearc decoupling followed by rapid subduction zone retreat; 3) B, breakoff of subducting lithosphere followed by re-initiation of subduction and in some cases, forearc decoupling (B-R). In one case (BA-B-R; where BA denotes backarc) subduction zone retreat follows backarc rifting. Subduction zone decoupling is analyzed using frictional-plastic yield theory and the Stefan solution for the separation of plates containing a viscous fluid. The numerical model results are used to explain the formation of Xigaze group ophiolites, southern Tibet, which formed in the Lhasa terrane forearc, likely following earlier subduction and not necessarily during subduction initiation. Either there was normal coupled subduction before subduction zone decoupling, or precursor slab breakoff, subduction re-initiation and then decoupling. Rapid deep upper-mantle circulation in the models during subduction zone retreat can exhume and emplace material in the forearc proto-ophiolite from as deep as the mantle transition zone, thereby explaining diamonds and other 10-15 GPa UHP phases in Tibetan ophiolites.

Sensitivity enhancement for detection of hyperpolarized 13 C MRI probes with 1 H spin coupling introduced by enzymatic transformation in vivo.

PubMed

von Morze, Cornelius; Tropp, James; Chen, Albert P; Marco-Rius, Irene; Van Criekinge, Mark; Skloss, Timothy W; Mammoli, Daniele; Kurhanewicz, John; Vigneron, Daniel B; Ohliger, Michael A; Merritt, Matthew E

2018-07-01

Although 1 H spin coupling is generally avoided in probes for hyperpolarized (HP) 13 C MRI, enzymatic transformations of biological interest can introduce large 13 C- 1 H couplings in vivo. The purpose of this study was to develop and investigate the application of 1 H decoupling for enhancing the sensitivity for detection of affected HP 13 C metabolic products. A standalone 1 H decoupler system and custom concentric 13 C/ 1 H paddle coil setup were integrated with a clinical 3T MRI scanner for in vivo 13 C MR studies using HP [2- 13 C]dihydroxyacetone, a novel sensor of hepatic energy status. Major 13 C- 1 H coupling J CH  = ∼150 Hz) is introduced after adenosine triphosphate-dependent enzymatic transformation of HP [2- 13 C]dihydroxyacetone to [2- 13 C]glycerol-3-phosphate in vivo. Application of WALTZ-16 1 H decoupling for elimination of large 13 C- 1 H couplings was first tested in thermally polarized glycerol phantoms and then for in vivo HP MR studies in three rats, scanned both with and without decoupling. As configured, 1 H-decoupled 13 C MR of thermally polarized glycerol and the HP metabolic product [2- 13 C]glycerol-3-phosphate was achieved at forward power of approximately 15 W. High-quality 3-s dynamic in vivo HP 13 C MR scans were acquired with decoupling duty cycle of 5%. Application of 1 H decoupling resulted in sensitivity enhancement of 1.7-fold for detection of metabolic conversion of [2- 13 C]dihydroxyacetone to HP [2- 13 C]glycerol-3-phosphate in vivo. Application of 1 H decoupling provides significant sensitivity enhancement for detection of HP 13 C metabolic products with large 1 H spin couplings, and is therefore expected to be useful for preclinical and potentially clinical HP 13 C MR studies. Magn Reson Med 80:36-41, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Easy-Going On-Spectrometer Optimisation of Phase Modulated Homonuclear Decoupling Sequences in Solid-State NMR

NASA Astrophysics Data System (ADS)

Grimminck, Dennis L. A. G.; Vasa, Suresh K.; Meerts, W. Leo; Kentgens, P. M.

2011-06-01

A global optimisation scheme for phase modulated proton homonuclear decoupling sequences in solid-state NMR is presented. Phase modulations, parameterised by DUMBO Fourier coefficients, were optimized using a Covariance Matrix Adaptation Evolution Strategies algorithm. Our method, denoted EASY-GOING homonuclear decoupling, starts with featureless spectra and optimises proton-proton decoupling, during either proton or carbon signal detection. On the one hand, our solutions closely resemble (e)DUMBO for moderate sample spinning frequencies and medium radio-frequency (rf) field strengths. On the other hand, the EASY-GOING approach resulted in a superior solution, achieving significantly better resolved proton spectra at very high 680 kHz rf field strength. N. Hansen, and A. Ostermeier. Evol. Comput. 9 (2001) 159-195 B. Elena, G. de Paepe, L. Emsley. Chem. Phys. Lett. 398 (2004) 532-538

Proton decoupling and recoupling under double-nutation irradiation in solid-state NMR

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

Takeda, Kazuyuki, E-mail: takezo@kuchem.kyoto-u.ac.jp; Wakisaka, Asato; Takegoshi, K.

The effect of {sup 1}H decoupling in magic-angle spinning solid-state NMR is studied under radiofrequency irradiation causing simultaneous nutations around a pair of orthogonal axes. Double-nutation with an arbitrary pair of nutation frequencies is implemented through modulation of the amplitude, phase, and frequency of the transmitting pulses. Similarity and difference of double-nutation decoupling and two-pulse phase-modulation decoupling schemes [A. E. Bennett, C. M. Rienstra, M. Auger, K. V. Lakshmi, and R. G. Griffin, J. Chem. Phys. 103, 6951–6958 (1995) and I. Scholz, P. Hodgkinson, B. H. Meier, and M. Ernst, J. Chem. Phys. 130, 114510 (2009)] are discussed. The structuremore » of recoupling bands caused by interference of the {sup 1}H spin nutation with sample spinning is studied by both experiments and numerical simulations.« less

Time-varying sliding-coefficient-based decoupled terminal sliding-mode control for a class of fourth-order systems.

PubMed

Bayramoglu, Husnu; Komurcugil, Hasan

2014-07-01

A time-varying sliding-coefficient-based decoupled terminal sliding mode control strategy is presented for a class of fourth-order systems. First, the fourth-order system is decoupled into two second-order subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients. Then, the control target of one subsystem to another subsystem was embedded. Thereafter, a terminal sliding mode control method was utilized to make both subsystems converge to their equilibrium points in finite time. The simulation results on the inverted pendulum system demonstrate that the proposed method exhibits a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Removal of slow-pulsing artifacts in in-phase 15N relaxation dispersion experiments using broadband 1H decoupling.

PubMed

Chatterjee, Soumya Deep; Ubbink, Marcellus; van Ingen, Hugo

2018-06-02

Understanding of the molecular mechanisms of protein function requires detailed insight into the conformational landscape accessible to the protein. Conformational changes can be crucial for biological processes, such as ligand binding, protein folding, and catalysis. NMR spectroscopy is exquisitely sensitive to such dynamic changes in protein conformations. In particular, Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments are a powerful tool to investigate protein dynamics on a millisecond time scale. CPMG experiments that probe the chemical shift modulation of 15 N in-phase magnetization are particularly attractive, due to their high sensitivity. These experiments require high power 1 H decoupling during the CPMG period to keep the 15 N magnetization in-phase. Recently, an improved version of the in-phase 15 N-CPMG experiment was introduced, offering greater ease of use by employing a single 1 H decoupling power for all CPMG pulsing rates. In these experiments however, incomplete decoupling of off-resonance amide 1 H spins introduces an artefactual dispersion of relaxation rates, the so-called slow-pulsing artifact. Here, we analyze the slow-pulsing artifact in detail and demonstrate that it can be suppressed through the use of composite pulse decoupling (CPD). We report the performances of various CPD schemes and show that CPD decoupling based on the 90 x -240 y -90 x element results in high-quality dispersion curves free of artifacts, even for amides with high 1 H offset.

Mind wandering minimizes mind numbing: Reducing semantic-satiation effects through absorptive lapses of attention.

PubMed

Mooneyham, Benjamin W; Schooler, Jonathan W

2016-08-01

Mind wandering is associated with perceptual decoupling: the disengagement of attention from perception. This decoupling is deleterious to performance in many situations; however, we sought to determine whether it might occur in the service of performance in certain circumstances. In two studies, we examined the role of mind wandering in a test of "semantic satiation," a phenomenon in which the repeated presentation of a word reduces semantic priming for a subsequently presented semantic associate. We posited that the attentional and perceptual decoupling associated with mind wandering would reduce the amount of satiation in the semantic representations of repeatedly presented words, thus leading to a reduced semantic-satiation effect. Our results supported this hypothesis: Self-reported mind-wandering episodes (Study 1) and behavioral indices of decoupled attention (Study 2) were both predictive of maintained semantic priming in situations predicted to induce semantic satiation. Additionally, our results suggest that moderate inattention to repetitive stimuli is not sufficient to enable "dishabituation": the refreshment of cognitive performance that results from diverting attention away from the task at hand. Rather, full decoupling is necessary to reap the benefits of mind wandering and to minimize mind numbing.

Decoupled scheme based on the Hermite expansion to construct lattice Boltzmann models for the compressible Navier-Stokes equations with arbitrary specific heat ratio.

PubMed

Hu, Kainan; Zhang, Hongwu; Geng, Shaojuan

2016-10-01

A decoupled scheme based on the Hermite expansion to construct lattice Boltzmann models for the compressible Navier-Stokes equations with arbitrary specific heat ratio is proposed. The local equilibrium distribution function including the rotational velocity of particle is decoupled into two parts, i.e., the local equilibrium distribution function of the translational velocity of particle and that of the rotational velocity of particle. From these two local equilibrium functions, two lattice Boltzmann models are derived via the Hermite expansion, namely one is in relation to the translational velocity and the other is connected with the rotational velocity. Accordingly, the distribution function is also decoupled. After this, the evolution equation is decoupled into the evolution equation of the translational velocity and that of the rotational velocity. The two evolution equations evolve separately. The lattice Boltzmann models used in the scheme proposed by this work are constructed via the Hermite expansion, so it is easy to construct new schemes of higher-order accuracy. To validate the proposed scheme, a one-dimensional shock tube simulation is performed. The numerical results agree with the analytical solutions very well.

A New Hybrid BFOA-PSO Optimization Technique for Decoupling and Robust Control of Two-Coupled Distillation Column Process.

PubMed

Abdelkarim, Noha; Mohamed, Amr E; El-Garhy, Ahmed M; Dorrah, Hassen T

2016-01-01

The two-coupled distillation column process is a physically complicated system in many aspects. Specifically, the nested interrelationship between system inputs and outputs constitutes one of the significant challenges in system control design. Mostly, such a process is to be decoupled into several input/output pairings (loops), so that a single controller can be assigned for each loop. In the frame of this research, the Brain Emotional Learning Based Intelligent Controller (BELBIC) forms the control structure for each decoupled loop. The paper's main objective is to develop a parameterization technique for decoupling and control schemes, which ensures robust control behavior. In this regard, the novel optimization technique Bacterial Swarm Optimization (BSO) is utilized for the minimization of summation of the integral time-weighted squared errors (ITSEs) for all control loops. This optimization technique constitutes a hybrid between two techniques, which are the Particle Swarm and Bacterial Foraging algorithms. According to the simulation results, this hybridized technique ensures low mathematical burdens and high decoupling and control accuracy. Moreover, the behavior analysis of the proposed BELBIC shows a remarkable improvement in the time domain behavior and robustness over the conventional PID controller.

Effect of Chain Rigidity on the Decoupling of Ion Motion from Segmental Relaxation in Polymerized Ionic Liquids: Ambient and Elevated Pressure Studies

DOE PAGES

Wojnarowska, Zaneta; Feng, Hongbo; Fu, Yao; ...

2017-08-21

Conductivity in polymer electrolytes has been generally discussed with the assumption that the segmental motions control charge transport. However, much less attention has been paid to the mechanism of ion conductivity where the motions of ions are less dependent (decoupled) on segmental dynamics. We present that this phenomenon is observed in ionic materials as they approach their glass transition temperature and becomes essential for design and development of highly conducting solid polymer electrolytes. In this paper, we study the effect of chain rigidity on the decoupling of ion transport from segmental motion in three polymerized ionic liquids (polyILs) containing themore » same cation–anion pair but differing in flexibility of the polymer backbones and side groups. Analysis of dielectric and rheology data reveals that decoupling is strong in vinyl-based rigid polymers while almost negligible in novel siloxane-based flexible polyILs. To explain this behavior, we investigated ion and chain dynamics at ambient and elevated pressure. Our results suggest that decoupling has a direct relationship to the frustration in chain packing and free volume. Finally, these conclusions are also supported by coarse-grained molecular dynamics simulations.« less

A New Hybrid BFOA-PSO Optimization Technique for Decoupling and Robust Control of Two-Coupled Distillation Column Process

PubMed Central

Mohamed, Amr E.; Dorrah, Hassen T.

2016-01-01

The two-coupled distillation column process is a physically complicated system in many aspects. Specifically, the nested interrelationship between system inputs and outputs constitutes one of the significant challenges in system control design. Mostly, such a process is to be decoupled into several input/output pairings (loops), so that a single controller can be assigned for each loop. In the frame of this research, the Brain Emotional Learning Based Intelligent Controller (BELBIC) forms the control structure for each decoupled loop. The paper's main objective is to develop a parameterization technique for decoupling and control schemes, which ensures robust control behavior. In this regard, the novel optimization technique Bacterial Swarm Optimization (BSO) is utilized for the minimization of summation of the integral time-weighted squared errors (ITSEs) for all control loops. This optimization technique constitutes a hybrid between two techniques, which are the Particle Swarm and Bacterial Foraging algorithms. According to the simulation results, this hybridized technique ensures low mathematical burdens and high decoupling and control accuracy. Moreover, the behavior analysis of the proposed BELBIC shows a remarkable improvement in the time domain behavior and robustness over the conventional PID controller. PMID:27807444

Effect of Chain Rigidity on the Decoupling of Ion Motion from Segmental Relaxation in Polymerized Ionic Liquids: Ambient and Elevated Pressure Studies

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

Wojnarowska, Zaneta; Feng, Hongbo; Fu, Yao

Conductivity in polymer electrolytes has been generally discussed with the assumption that the segmental motions control charge transport. However, much less attention has been paid to the mechanism of ion conductivity where the motions of ions are less dependent (decoupled) on segmental dynamics. We present that this phenomenon is observed in ionic materials as they approach their glass transition temperature and becomes essential for design and development of highly conducting solid polymer electrolytes. In this paper, we study the effect of chain rigidity on the decoupling of ion transport from segmental motion in three polymerized ionic liquids (polyILs) containing themore » same cation–anion pair but differing in flexibility of the polymer backbones and side groups. Analysis of dielectric and rheology data reveals that decoupling is strong in vinyl-based rigid polymers while almost negligible in novel siloxane-based flexible polyILs. To explain this behavior, we investigated ion and chain dynamics at ambient and elevated pressure. Our results suggest that decoupling has a direct relationship to the frustration in chain packing and free volume. Finally, these conclusions are also supported by coarse-grained molecular dynamics simulations.« less

Optimization of decoupling performance of underwater acoustic coating with cavities via equivalent fluid model

NASA Astrophysics Data System (ADS)

Huang, Lingzhi; Xiao, Yong; Wen, Jihong; Zhang, Hao; Wen, Xisen

2018-07-01

Acoustic coatings with periodically arranged internal cavities have been successfully applied in submarines for the purpose of decoupling water from vibration of underwater structures, and thus reducing underwater sound radiation. Previous publications on decoupling acoustic coatings with cavities are mainly focused on the case of coatings with specific shaped cavities, including cylindrical and conical cavities. To explore better decoupling performance, an optimal design of acoustic coating with complex shaped cavities is attempted in this paper. An equivalent fluid model is proposed to characterize coatings with general axisymmetrical cavities. By employing the equivalent fluid model, an analytical vibroacoustic model is further developed for the prediction of sound radiation from an infinite plate covered with an equivalent fluid layer (as a replacement of original coating) and immersed in water. Numerical examples are provided to verify the equivalent fluid model. Based on a combining use of the analytical vibroacoustic model and a differential evolution algorithm, optimal designs for acoustic coatings with cavities are conducted. Numerical results demonstrate that the decoupling performance of acoustic coating can be significantly improved by employing special axisymmetrical cavities as compared to traditional cylindrical cavities.

State policy change: Revenue decoupling in the electricity market

NASA Astrophysics Data System (ADS)

McNeil, Kytson L.

The study seeks to answer the question, why are states adopting revenue decoupling in the electricity market, by investigating the relationship between policy adoption and attributes of the electricity market, the structure of the state utility commissions, and the political climate of the state. The study examines the period 1978-2008. Two econometric models, the marginal risk set model and the conditional risk set model, are estimated to predict the influence of covariates on the probability of the state adopting revenue decoupling in the electricity market. The models are both variants of the Cox proportional hazard model and use different underlying assumptions about the nature of adoption of revenue decoupling and when the states are considered to be at risk of adoption. Results suggest that market attributes, such as the source of electricity generation in the state, state energy intensity, and the distribution of non-public and public utilities, significantly influence the adoption of the policy. Also, the method of selecting commissioners and the party affiliation of elected officials in the state are important factors. The study concludes by suggestions to improve the implementation and evaluation of revenue decoupling in the electricity markets.

Decoupled systems on trial: Eliminating bottlenecks to improve aquaponic processes.

PubMed

Monsees, Hendrik; Kloas, Werner; Wuertz, Sven

2017-01-01

In classical aquaponics (coupled aquaponic systems, 1-loop systems) the production of fish in recirculating aquaculture systems (RAS) and plants in hydroponics are combined in a single loop, entailing systemic compromises on the optimal production parameters (e.g. pH). Recently presented decoupled aquaponics (2-loop systems) have been awarded for eliminating major bottlenecks. In a pilot study, production in an innovative decoupled aquaponic system was compared with a coupled system and, as a control, a conventional RAS, assessing growth parameters of fish (FCR, SGR) and plants over an experimental period of 5 months. Soluble nutrients (NO3--N, NO2--N, NH4+-N, PO43-, K+, Ca2+, Mg2+, SO42-, Cl2- and Fe2+), elemental composition of plants, fish and sludge (N, P, K, Ca, Mg, Na, C), abiotic factors (temperature, pH, oxygen, and conductivity), fertilizer and water consumption were determined. Fruit yield was 36% higher in decoupled aquaponics and pH and fertilizer management was more effective, whereas fish production was comparable in both systems. The results of this pilot study clearly illustrate the main advantages of decoupled, two-loop aquaponics and demonstrate how bottlenecks commonly encountered in coupled aquaponics can be managed to promote application in aquaculture.

High-resolution proton NMR studies of intracellular metabolites in yeast using 13C decoupling

NASA Astrophysics Data System (ADS)

Sillerud, Laurel O.; Alger, Jeffry R.; Shulman, Robert G.

The resolution and specificity of 1H NMR in studies of yeast cellular metabolism were increased by feeding a 13C-labeled substrate and observing 1H difference spectra in the presence and absence of 13C decoupling fields. [2- 13C]Acetate was utilized as a respiratory substrate in an aerobic suspension of Saccharomyces cerevisiae. The broad cellular background proton resonances are removed by the technique, leaving only signals from the protons of the substrate, or its metabolites, that are coupled to 13C. Spectra of the yeast suspension after acetate feeding show the disappearance of label from the acetate pool and the subsequent appearance of 13C in glutamate C 3 and C 4 and in aspartate C 3. These results are in accord with the known fluxes of metabolites. Selective single-frequency 13C decoupling was used to provide assignments for the difference signals. The limitations on single-frequency decoupling coming from finite decoupling fields are investigated. The technique shows a potential for application in a wide variety of systems where the resolution of the 13C spectrum may be combined with the sensitivity for proton detection to observe metabolites that have been previously unobservable.

Ground vibration test of F-16 airplane with initial decoupler pylon

NASA Technical Reports Server (NTRS)

Cazier, F. W., Jr.; Kehoe, M. W.

1984-01-01

A ground vibration test was conducted on an F-16 airplane loaded on each wing with a 370-gal tank mounted on a standard pylon, a GBU-8 store mounted on a decoupler pylon, and an AIM-9J missile mounted on a wing-tip launcher. The decoupler pylon is a passive wing/store flutter-suppression device. The test was conducted prior to initial flight tests to determine the modal frequencies, mode shapes, and structural damping coefficients. The data presented include frequency response plots, force effect plots, and limited mode shape data.

Multiple estimation channel decoupling and optimization method based on inverse system

NASA Astrophysics Data System (ADS)

Wu, Peng; Mu, Rongjun; Zhang, Xin; Deng, Yanpeng

2018-03-01

This paper addressed the intelligent autonomous navigation request of intelligent deformation missile, based on the intelligent deformation missile dynamics and kinematics modeling, navigation subsystem solution method and error modeling, and then focuses on the corresponding data fusion and decision fusion technology, decouples the sensitive channel of the filter input through the inverse system of design dynamics to reduce the influence of sudden change of the measurement information on the filter input. Then carrying out a series of simulation experiments, which verified the feasibility of the inverse system decoupling algorithm effectiveness.

Robust dynamical decoupling for quantum computing and quantum memory.

PubMed

Souza, Alexandre M; Alvarez, Gonzalo A; Suter, Dieter

2011-06-17

Dynamical decoupling (DD) is a popular technique for protecting qubits from the environment. However, unless special care is taken, experimental errors in the control pulses used in this technique can destroy the quantum information instead of preserving it. Here, we investigate techniques for making DD sequences robust against different types of experimental errors while retaining good decoupling efficiency in a fluctuating environment. We present experimental data from solid-state nuclear spin qubits and introduce a new DD sequence that is suitable for quantum computing and quantum memory.

On the design of decoupling controllers for advanced rotorcraft in the hover case

NASA Technical Reports Server (NTRS)

Fan, M. K. H.; Tits, A.; Barlow, J.; Tsing, N. K.; Tischler, M.; Takahashi, M.

1991-01-01

A methodology for design of helicopter control systems is proposed that can account for various types of concurrent specifications: stability, decoupling between longitudinal and lateral motions, handling qualities, and physical limitations of the swashplate motions. This is achieved by synergistic use of analytical techniques (Q-parameterization of all stabilizing controllers, transfer function interpolation) and advanced numerical optimization techniques. The methodology is used to design a controller for the UH-60 helicopter in hover. Good results are achieved for decoupling and handling quality specifications.

A mechanism for decoupling within the oceanic lithosphere revealed in the Troodos ophiolite

USGS Publications Warehouse

Agar, Susan M.; Klitgord, Kim D.

1995-01-01

Contrasting kinematic histories recorded in the sheeted dykes and underlying plutonic rocks of the Troodos ophiolite provide a new perspective on the mechanical evolution of oceanic spreading centres. The kinematic framework of the decoupling zone that partitions deformation between the sheeted dykes and plutonics contrasts with low-angle detachment models for slow-spreading ridges based on continental-rift analogues. A model for the generation of multiple, horizontal decoupling horizons, linked by planar normal faults, demonstrates new possibilities for the kinematic and rheological significance of seismic reflectors in oceanic lithosphere.

Supertrace formulae for nonlinearly realized supersymmetry

NASA Astrophysics Data System (ADS)

Murli, Divyanshu; Yamada, Yusuke

2018-04-01

We derive the general supertrace formula for a system with N chiral superfields and one nilpotent chiral superfield in global and local supersymmetry. The nilpotent multiplet is realized by taking the scalar-decoupling limit of a chiral superfield breaking supersymmetry spontaneously. As we show, however, the modified formula is not simply related to the scalar-decoupling limit of the supertrace in linearly-realized supersymmetry. We also show that the supertrace formula reduces to that of a linearly realized supersymmetric theory with a decoupled sGoldstino if the Goldstino is the fermion in the nilpotent multiplet.

Li-air batteries: Decouple to stabilize

NASA Astrophysics Data System (ADS)

Xu, Ji-Jing; Zhang, Xin-Bo

2017-09-01

The utilization of porous carbon cathodes in lithium-air batteries is hindered by their severe decomposition during battery cycling. Now, dual redox mediators are shown to decouple the complex electrochemical reactions at the cathode, avoiding cathode passivation and decomposition.

Multi-faults decoupling on turbo-expander using differential-based ensemble empirical mode decomposition

NASA Astrophysics Data System (ADS)

Li, Hongguang; Li, Ming; Li, Cheng; Li, Fucai; Meng, Guang

2017-09-01

This paper dedicates on the multi-faults decoupling of turbo-expander rotor system using Differential-based Ensemble Empirical Mode Decomposition (DEEMD). DEEMD is an improved version of DEMD to resolve the imperfection of mode mixing. The nonlinear behaviors of the turbo-expander considering temperature gradient with crack, rub-impact and pedestal looseness faults are investigated respectively, so that the baseline for the multi-faults decoupling can be established. DEEMD is then utilized on the vibration signals of the rotor system with coupling faults acquired by numerical simulation, and the results indicate that DEEMD can successfully decouple the coupling faults, which is more efficient than EEMD. DEEMD is also applied on the vibration signal of the misalignment coupling with rub-impact fault obtained during the adjustment of the experimental system. The conclusion shows that DEEMD can decompose the practical multi-faults signal and the industrial prospect of DEEMD is verified as well.

Electronically decoupled stacking fault tetrahedra embedded in Au(111) films

PubMed Central

Schouteden, Koen; Amin-Ahmadi, Behnam; Li, Zhe; Muzychenko, Dmitry; Schryvers, Dominique; Van Haesendonck, Chris

2016-01-01

Stacking faults are known as defective structures in crystalline materials that typically lower the structural quality of the material. Here, we show that a particular type of defect, that is, stacking fault tetrahedra (SFTs), exhibits pronounced quantized electronic behaviour, revealing a potential synthetic route to decoupled nanoparticles in metal films. We report on the electronic properties of SFTs that exist in Au(111) films, as evidenced by scanning tunnelling microscopy and confirmed by transmission electron microscopy. We find that the SFTs reveal a remarkable decoupling from their metal surroundings, leading to pronounced energy level quantization effects within the SFTs. The electronic behaviour of the SFTs can be described well by the particle-in-a-box model. Our findings demonstrate that controlled preparation of SFTs may offer an alternative way to achieve well-decoupled nanoparticles of high crystalline quality in metal thin films without the need of thin insulating layers. PMID:28008910

Electronically decoupled stacking fault tetrahedra embedded in Au(111) films.

PubMed

Schouteden, Koen; Amin-Ahmadi, Behnam; Li, Zhe; Muzychenko, Dmitry; Schryvers, Dominique; Van Haesendonck, Chris

2016-12-23

Stacking faults are known as defective structures in crystalline materials that typically lower the structural quality of the material. Here, we show that a particular type of defect, that is, stacking fault tetrahedra (SFTs), exhibits pronounced quantized electronic behaviour, revealing a potential synthetic route to decoupled nanoparticles in metal films. We report on the electronic properties of SFTs that exist in Au(111) films, as evidenced by scanning tunnelling microscopy and confirmed by transmission electron microscopy. We find that the SFTs reveal a remarkable decoupling from their metal surroundings, leading to pronounced energy level quantization effects within the SFTs. The electronic behaviour of the SFTs can be described well by the particle-in-a-box model. Our findings demonstrate that controlled preparation of SFTs may offer an alternative way to achieve well-decoupled nanoparticles of high crystalline quality in metal thin films without the need of thin insulating layers.

Coupling and decoupling of the accelerating units for pulsed synchronous linear accelerator

NASA Astrophysics Data System (ADS)

Shen, Yi; Liu, Yi; Ye, Mao; Zhang, Huang; Wang, Wei; Xia, Liansheng; Wang, Zhiwen; Yang, Chao; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun

2017-12-01

A pulsed synchronous linear accelerator (PSLA), based on the solid-state pulse forming line, photoconductive semiconductor switch, and high gradient insulator technologies, is a novel linear accelerator. During the prototype PSLA commissioning, the energy gain of proton beams was found to be much lower than expected. In this paper, the degradation of the energy gain is explained by the circuit and cavity coupling effect of the accelerating units. The coupling effects of accelerating units are studied, and the circuit topologies of these two kinds of coupling effects are presented. Two methods utilizing inductance and membrane isolations, respectively, are proposed to reduce the circuit coupling effects. The effectiveness of the membrane isolation method is also supported by simulations. The decoupling efficiency of the metal drift tube is also researched. We carried out the experiments on circuit decoupling of the multiple accelerating cavity. The result shows that both circuit decoupling methods could increase the normalized voltage.

Optimally combining dynamical decoupling and quantum error correction.

PubMed

Paz-Silva, Gerardo A; Lidar, D A

2013-01-01

Quantum control and fault-tolerant quantum computing (FTQC) are two of the cornerstones on which the hope of realizing a large-scale quantum computer is pinned, yet only preliminary steps have been taken towards formalizing the interplay between them. Here we explore this interplay using the powerful strategy of dynamical decoupling (DD), and show how it can be seamlessly and optimally integrated with FTQC. To this end we show how to find the optimal decoupling generator set (DGS) for various subspaces relevant to FTQC, and how to simultaneously decouple them. We focus on stabilizer codes, which represent the largest contribution to the size of the DGS, showing that the intuitive choice comprising the stabilizers and logical operators of the code is in fact optimal, i.e., minimizes a natural cost function associated with the length of DD sequences. Our work brings hybrid DD-FTQC schemes, and their potentially considerable advantages, closer to realization.

Optimally combining dynamical decoupling and quantum error correction

PubMed Central

Paz-Silva, Gerardo A.; Lidar, D. A.

2013-01-01

Quantum control and fault-tolerant quantum computing (FTQC) are two of the cornerstones on which the hope of realizing a large-scale quantum computer is pinned, yet only preliminary steps have been taken towards formalizing the interplay between them. Here we explore this interplay using the powerful strategy of dynamical decoupling (DD), and show how it can be seamlessly and optimally integrated with FTQC. To this end we show how to find the optimal decoupling generator set (DGS) for various subspaces relevant to FTQC, and how to simultaneously decouple them. We focus on stabilizer codes, which represent the largest contribution to the size of the DGS, showing that the intuitive choice comprising the stabilizers and logical operators of the code is in fact optimal, i.e., minimizes a natural cost function associated with the length of DD sequences. Our work brings hybrid DD-FTQC schemes, and their potentially considerable advantages, closer to realization. PMID:23559088

Optically transmitted and inductively coupled electric reference to access in vivo concentrations for quantitative proton-decoupled ¹³C magnetic resonance spectroscopy.

PubMed

Chen, Xing; Pavan, Matteo; Heinzer-Schweizer, Susanne; Boesiger, Peter; Henning, Anke

2012-01-01

This report describes our efforts on quantification of tissue metabolite concentrations in mM by nuclear Overhauser enhanced and proton decoupled (13) C magnetic resonance spectroscopy and the Electric Reference To access In vivo Concentrations (ERETIC) method. Previous work showed that a calibrated synthetic magnetic resonance spectroscopy-like signal transmitted through an optical fiber and inductively coupled into a transmit/receive coil represents a reliable reference standard for in vivo (1) H magnetic resonance spectroscopy quantification on a clinical platform. In this work, we introduce a related implementation that enables simultaneous proton decoupling and ERETIC-based metabolite quantification and hence extends the applicability of the ERETIC method to nuclear Overhauser enhanced and proton decoupled in vivo (13) C magnetic resonance spectroscopy. In addition, ERETIC signal stability under the influence of simultaneous proton decoupling is investigated. The proposed quantification method was cross-validated against internal and external reference standards on human skeletal muscle. The ERETIC signal intensity stability was 100.65 ± 4.18% over 3 months including measurements with and without proton decoupling. Glycogen and unsaturated fatty acid concentrations measured with the ERETIC method were in excellent agreement with internal creatine and external phantom reference methods, showing a difference of 1.85 ± 1.21% for glycogen and 1.84 ± 1.00% for unsaturated fatty acid between ERETIC and creatine-based quantification, whereas the deviations between external reference and creatine-based quantification are 6.95 ± 9.52% and 3.19 ± 2.60%, respectively. Copyright © 2011 Wiley Periodicals, Inc.

Disturbance decoupling, decentralized control and the Riccati equation

NASA Technical Reports Server (NTRS)

Garzia, M. R.; Loparo, K. A.; Martin, C. F.

1981-01-01

The disturbance decoupling and optimal decentralized control problems are looked at using identical mathematical techniques. A statement of the problems and the development of their solution approach is presented. Preliminary results are given for the optimal decentralized control problem.

On the anomaly of velocity-pressure decoupling in collocated mesh solutions

NASA Technical Reports Server (NTRS)

Kim, Sang-Wook; Vanoverbeke, Thomas

1991-01-01

The use of various pressure correction algorithms originally developed for fully staggered meshes can yield a velocity-pressure decoupled solution for collocated meshes. The mechanism that causes velocity-pressure decoupling is identified. It is shown that the use of a partial differential equation for the incremental pressure eliminates such a mechanism and yields a velocity-pressure coupled solution. Example flows considered are a three dimensional lid-driven cavity flow and a laminar flow through a 90 deg bend square duct. Numerical results obtained using the collocated mesh are in good agreement with the measured data and other numerical results.

Protected quantum computing: interleaving gate operations with dynamical decoupling sequences.

PubMed

Zhang, Jingfu; Souza, Alexandre M; Brandao, Frederico Dias; Suter, Dieter

2014-02-07

Implementing precise operations on quantum systems is one of the biggest challenges for building quantum devices in a noisy environment. Dynamical decoupling attenuates the destructive effect of the environmental noise, but so far, it has been used primarily in the context of quantum memories. Here, we experimentally demonstrate a general scheme for combining dynamical decoupling with quantum logical gate operations using the example of an electron-spin qubit of a single nitrogen-vacancy center in diamond. We achieve process fidelities >98% for gate times that are 2 orders of magnitude longer than the unprotected dephasing time T2.

Digital controller design: Analysis of the annular suspension pointing system. [analog controllers with feedback

NASA Technical Reports Server (NTRS)

Kuo, B. C.

1978-01-01

The analog controllers of the annular suspension pointing system are designed for control of the chi, phi sub 1, and phi sub 2 bandwidth dynamics through decoupling and pole placement. Since it is virtually impossible to find an equivalent bandwidth of the overall system and establish a general eigenvalue requirement for the system, the subsystem dynamics are decoupled through state feedback and the poles are placed simultaneously to realize the desired bandwidths for the three system components. Decoupling and pole placement are also used to design the closed-loop digital system through approximation.

Analytical Methods of Decoupling the Automotive Engine Torque Roll Axis

NASA Astrophysics Data System (ADS)

JEONG, TAESEOK; SINGH, RAJENDRA

2000-06-01

This paper analytically examines the multi-dimensional mounting schemes of an automotive engine-gearbox system when excited by oscillating torques. In particular, the issue of torque roll axis decoupling is analyzed in significant detail since it is poorly understood. New dynamic decoupling axioms are presented an d compared with the conventional elastic axis mounting and focalization methods. A linear time-invariant system assumption is made in addition to a proportionally damped system. Only rigid-body modes of the powertrain are considered and the chassis elements are assumed to be rigid. Several simplified physical systems are considered and new closed-form solutions for symmetric and asymmetric engine-mounting systems are developed. These clearly explain the design concepts for the 4-point mounting scheme. Our analytical solutions match with the existing design formulations that are only applicable to symmetric geometries. Spectra for all six rigid-body motions are predicted using the alternate decoupling methods and the closed-form solutions are verified. Also, our method is validated by comparing modal solutions with prior experimental and analytical studies. Parametric design studies are carried out to illustrate the methodology. Chief contributions of this research include the development of new or refined analytical models and closed-form solutions along with improved design strategies for the torque roll axis decoupling.

Nonlinear Decoupling Control With ANFIS-Based Unmodeled Dynamics Compensation for a Class of Complex Industrial Processes.

PubMed

Zhang, Yajun; Chai, Tianyou; Wang, Hong; Wang, Dianhui; Chen, Xinkai

2018-06-01

Complex industrial processes are multivariable and generally exhibit strong coupling among their control loops with heavy nonlinear nature. These make it very difficult to obtain an accurate model. As a result, the conventional and data-driven control methods are difficult to apply. Using a twin-tank level control system as an example, a novel multivariable decoupling control algorithm with adaptive neural-fuzzy inference system (ANFIS)-based unmodeled dynamics (UD) compensation is proposed in this paper for a class of complex industrial processes. At first, a nonlinear multivariable decoupling controller with UD compensation is introduced. Different from the existing methods, the decomposition estimation algorithm using ANFIS is employed to estimate the UD, and the desired estimating and decoupling control effects are achieved. Second, the proposed method does not require the complicated switching mechanism which has been commonly used in the literature. This significantly simplifies the obtained decoupling algorithm and its realization. Third, based on some new lemmas and theorems, the conditions on the stability and convergence of the closed-loop system are analyzed to show the uniform boundedness of all the variables. This is then followed by the summary on experimental tests on a heavily coupled nonlinear twin-tank system that demonstrates the effectiveness and the practicability of the proposed method.

Decoupling control of vehicle chassis system based on neural network inverse system

NASA Astrophysics Data System (ADS)

Wang, Chunyan; Zhao, Wanzhong; Luan, Zhongkai; Gao, Qi; Deng, Ke

2018-06-01

Steering and suspension are two important subsystems affecting the handling stability and riding comfort of the chassis system. In order to avoid the interference and coupling of the control channels between active front steering (AFS) and active suspension subsystems (ASS), this paper presents a composite decoupling control method, which consists of a neural network inverse system and a robust controller. The neural network inverse system is composed of a static neural network with several integrators and state feedback of the original chassis system to approach the inverse system of the nonlinear systems. The existence of the inverse system for the chassis system is proved by the reversibility derivation of Interactor algorithm. The robust controller is based on the internal model control (IMC), which is designed to improve the robustness and anti-interference of the decoupled system by adding a pre-compensation controller to the pseudo linear system. The results of the simulation and vehicle test show that the proposed decoupling controller has excellent decoupling performance, which can transform the multivariable system into a number of single input and single output systems, and eliminate the mutual influence and interference. Furthermore, it has satisfactory tracking capability and robust performance, which can improve the comprehensive performance of the chassis system.

Decoupling Principle Analysis and Development of a Parallel Three-Dimensional Force Sensor

PubMed Central

Zhao, Yanzhi; Jiao, Leihao; Weng, Dacheng; Zhang, Dan; Zheng, Rencheng

2016-01-01

In the development of the multi-dimensional force sensor, dimension coupling is the ubiquitous factor restricting the improvement of the measurement accuracy. To effectively reduce the influence of dimension coupling on the parallel multi-dimensional force sensor, a novel parallel three-dimensional force sensor is proposed using a mechanical decoupling principle, and the influence of the friction on dimension coupling is effectively reduced by making the friction rolling instead of sliding friction. In this paper, the mathematical model is established by combining with the structure model of the parallel three-dimensional force sensor, and the modeling and analysis of mechanical decoupling are carried out. The coupling degree (ε) of the designed sensor is defined and calculated, and the calculation results show that the mechanical decoupling parallel structure of the sensor possesses good decoupling performance. A prototype of the parallel three-dimensional force sensor was developed, and FEM analysis was carried out. The load calibration and data acquisition experiment system are built, and then calibration experiments were done. According to the calibration experiments, the measurement accuracy is less than 2.86% and the coupling accuracy is less than 3.02%. The experimental results show that the sensor system possesses high measuring accuracy, which provides a basis for the applied research of the parallel multi-dimensional force sensor. PMID:27649194

Decoupled systems on trial: Eliminating bottlenecks to improve aquaponic processes

PubMed Central

Kloas, Werner; Wuertz, Sven

2017-01-01

In classical aquaponics (coupled aquaponic systems, 1-loop systems) the production of fish in recirculating aquaculture systems (RAS) and plants in hydroponics are combined in a single loop, entailing systemic compromises on the optimal production parameters (e.g. pH). Recently presented decoupled aquaponics (2-loop systems) have been awarded for eliminating major bottlenecks. In a pilot study, production in an innovative decoupled aquaponic system was compared with a coupled system and, as a control, a conventional RAS, assessing growth parameters of fish (FCR, SGR) and plants over an experimental period of 5 months. Soluble nutrients (NO3--N, NO2--N, NH4+-N, PO43-, K+, Ca2+, Mg2+, SO42-, Cl2- and Fe2+), elemental composition of plants, fish and sludge (N, P, K, Ca, Mg, Na, C), abiotic factors (temperature, pH, oxygen, and conductivity), fertilizer and water consumption were determined. Fruit yield was 36% higher in decoupled aquaponics and pH and fertilizer management was more effective, whereas fish production was comparable in both systems. The results of this pilot study clearly illustrate the main advantages of decoupled, two-loop aquaponics and demonstrate how bottlenecks commonly encountered in coupled aquaponics can be managed to promote application in aquaculture. PMID:28957357

Turbulence and Radiation in Stratocumulus-Topped Marine Boundary Layers: A Case Study from VOCALS-REx

DOE PAGES

Ghate, Virendra P.; Albrecht, Bruce A.; Miller, Mark A.; ...

2014-01-13

Observations made during a 24-h period as part of the Variability of the American Monsoon Systems (VAMOS) Ocean–Cloud–Atmosphere–Land Study Regional Experiment (VOCALS-REx) are analyzed to study the radiation and turbulence associated with the stratocumulus-topped marine boundary layer (BL). The first 14 h exhibited a well-mixed (coupled) BL with an average cloud-top radiative flux divergence of ~130 W m 22; the BL was decoupled during the last 10 h with negligible radiative flux divergence. The averaged radiative cooling very close to the cloud top was -9.04 K h -1 in coupled conditions and -3.85 K h -1 in decoupled conditions. Thismore » is the first study that combined data from a vertically pointing Doppler cloud radar and a Doppler lidar to yield the vertical velocity structure of the entire BL. The averaged vertical velocity variance and updraft mass flux during coupled conditions were higher than those during decoupled conditions at all levels by a factor of 2 or more. The vertical velocity skewness was negative in the entire BL during coupled conditions, whereas it was weakly positive in the lower third of the BL and negative above during decoupled conditions. A formulation of velocity scale is proposed that includes the effect of cloud-top radiative cooling in addition to the surface buoyancy flux. When scaled by the velocity scale, the vertical velocity variance and coherent downdrafts had similar magnitude during the coupled and decoupled conditions. Finally, the coherent updrafts that exhibited a constant profile in the entire BL during both the coupled and decoupled conditions scaled well with the convective velocity scale to a value of ~0.5.« less

Atomic-powered democracy: Policy against politics in the quest for American nuclear energy

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

Williams, R.W.

This dissertation focuses on the relationship of American nuclear energy to democracy. It examines whether the nuclear policy processes have furthered the legitimacy-government accountability and citizen participation-which the democratic institutes are based. Nuclear policy and its institutions have placed severe limitations on democratic practices. Contravened democracy is seen most clearly in the decoupling of policy from politics. Decoupling refers to the weakening of institutional linkages between citizens and government, and to the erosion of the norms that ground liberal democracy. Decoupling is manifested in policy centralization, procedural biases, technical rationality, and the spatial displacement of conflict. Decoupling has normative implications:more » While federal accountability was limited and citizen participation was shackled, other major groups enjoyed privileged access to policy making. The decoupling of nuclear policy from politics arose within the context of US liberal-democratic capitalism. The federal government pursued its own goals of defense and world leadership. Yet, it was not structurally autonomous from the hegemony of the political-economic context. Economically, the Atomic Energy Act did not permit federal agencies to directly invest in power plant construction, and did not authorize them to commercially generate electricity. Private industry was structurally placed to domesticate the atom. Politically, the liberal-democratic system hampered an unquestioning pursuit of atomic energy. Federal institutions have been forced to heed some of the anti-nuclear concerns. The pervasive influence of the US political economy on nuclear policy has come to transgress democracy. Nuclear power's growth faltered during the 1970s. The political and economic constraints on federal actions have limited the means available to revive a becalmed nuclear industry; this has exerted strong pressure on federal institutions to decouple policy from participation.« less

Top-down, decoupled control of constitutive parameters in electromagnetic metamaterials with dielectric resonators of internal anisotropy.

PubMed

Koo, Sukmo; Mason, Daniel R; Kim, Yunjung; Park, Namkyoo

2017-02-10

A meta-atom platform providing decoupled tuning for the constitutive wave parameters remains as a challenging problem, since the proposition of Pendry. Here we propose an electromagnetic meta-atom design of internal anisotropy (ε r  ≠ ε θ ), as a pathway for decoupling of the effective- permittivity ε eff and permeability μ eff . Deriving effective parameters for anisotropic meta-atom from the first principles, and then subsequent inverse-solving the obtained decoupled solution for a target set of ε eff and μ eff , we also achieve an analytic, top-down determination for the internal structure of a meta-atom. To realize the anisotropy from isotropic materials, a particle of spatial permittivity modulation in r or θ direction is proposed. As an application example, a matched zero index dielectric meta-atom is demonstrated, to enable the super-funneling of a 50λ-wide flux through a sub-λ slit; unharnessing the flux collection limit dictated by the λ-zone.

Study of the choice of the decoupling layout for the ITER ICRH system

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

Vervier, M., E-mail: michel.vervier@rma.ac.be; Messiaen, A.; Ongena, J.

10 decouplers are used to neutralize the mutual coupling effects and to control the current amplitude of the 24 straps array of the ITER ICRH antenna in the case of current drive phasing. In the case of heating phasing only 4 decouplers are active and the array current control needs to act on the ratio between the power delivered by the 4 generators. This ratio is very sensitive to the precise adjustment of the antenna array phasing. The maximum total radiated power capability is then limited when the power of one generator reaches its maximum value. With the addition ofmore » four switches all 10 installed decouplers are made active and can act on all mutual coupling effects with equal source power from the 4 generators. With four more switches the current drive phasing could work with a reduced poloidal phasing resulting in a 35% increase of its coupling to the plasma.« less

Decoupling control of steering and driving system for in-wheel-motor-drive electric vehicle

NASA Astrophysics Data System (ADS)

Zhang, Han; Zhao, Wanzhong

2018-02-01

To improve the maneuverability and stability of in-wheel-motor-drive electric vehicle, a control strategy based on nonlinear decoupling control method is proposed in this paper, realizing the coordinated control of the steering and driving system. At first, the nonlinear models of the in-wheel-motor-drive electric vehicle and its sub-system are constructed. Then the inverse system decoupling theory is applied to decompose the nonlinear system into several independent subsystems, which makes it possible to realize the coordinated control of each subsystem. Next, the μ-Synthesis theory is applied to eliminate the influence of model uncertainty, improving the stability, robustness and tracking performance of in-wheel-motor-drive electric vehicle. Simulation and experiment results and numerical analyses, based on the electric vehicle actuated by in-wheel-motors, prove that the proposed control method is effective to accomplish the decoupling control of the steering and driving system in both simulation and real practice.

Top-down, decoupled control of constitutive parameters in electromagnetic metamaterials with dielectric resonators of internal anisotropy

NASA Astrophysics Data System (ADS)

Koo, Sukmo; Mason, Daniel R.; Kim, Yunjung; Park, Namkyoo

2017-02-01

A meta-atom platform providing decoupled tuning for the constitutive wave parameters remains as a challenging problem, since the proposition of Pendry. Here we propose an electromagnetic meta-atom design of internal anisotropy (εr ≠ εθ), as a pathway for decoupling of the effective- permittivity εeff and permeability μeff. Deriving effective parameters for anisotropic meta-atom from the first principles, and then subsequent inverse-solving the obtained decoupled solution for a target set of εeff and μeff, we also achieve an analytic, top-down determination for the internal structure of a meta-atom. To realize the anisotropy from isotropic materials, a particle of spatial permittivity modulation in r or θ direction is proposed. As an application example, a matched zero index dielectric meta-atom is demonstrated, to enable the super-funneling of a 50λ-wide flux through a sub-λ slit; unharnessing the flux collection limit dictated by the λ-zone.

The origin of decoupled carbonate and organic carbon isotope signatures in the early Cambrian (ca. 542-520 Ma) Yangtze platform

NASA Astrophysics Data System (ADS)

Jiang, Ganqing; Wang, Xinqiang; Shi, Xiaoying; Xiao, Shuhai; Zhang, Shihong; Dong, Jin

2012-02-01

The early Cambrian (ca. 542-520 Ma) strata in South China record two prominent negative carbonate carbon isotope (δ13Ccarb) excursions of early Nemakit-Daldynian (N-D) and early Tommotian ages. Across each of these excursions, carbonate and organic carbon isotopes (δ13Ccarb and δ13Corg) are strongly decoupled. Regional correlation across a shelf-to-basin transect shows lateral heterogeneity of δ13Corg during the early-middle N-D but more homogenized δ13Corg values across the basin during the late N-D and Tommotian. The temporal and lateral variations in δ13Corg suggest that decoupled δ13Ccarb and δ13Corg across the N-D δ13Ccarb excursion were possibly caused by diagenetic alteration of organic matter and/or amplification of detrital organic carbon isotope signature in low-TOC carbonates. In contrast, decoupled δ13Ccarb and δ13Corg of the upper N-D and Tommotian were likely resulted from chemoautotrophic-methanotrophic biomass contribution to TOC in organic-rich black shale and carbonates. The decoupled δ13Ccarb-δ13Corg pattern from the lower N-D strata (ca. 542 Ma) shows striking similarities with those from the basal (ca. 635 Ma) and upper (ca. 551 Ma) Doushantuo Formation. In all three cases, decoupled δ13Ccarb-δ13Corg are seen in organic-poor carbonates (TOC ≤ 0.1‰) and coupled δ13Ccarb-δ13Corg occur in organic-rich black shale and carbonates at the end of the negative δ13Ccarb excursion. These similarities suggest that the shift from decoupled to coupled δ13Ccarb-δ13Corg has no causal link with the terminal oxidation of a large oceanic DOC reservoir. Given the pervasive anoxia/euxinia in Ediacaran-early Cambrian oceans, local DOC-rich environments may have been common, but a large oceanic DOC reservoir capable of buffering the δ13C of marine organic matter requires independent evidence.

Announcement/Subscription/Publication: Message Based Communication for Heterogeneous Mobile Environments

NASA Astrophysics Data System (ADS)

Ristau, Henry

Many tasks in smart environments can be implemented using message based communication paradigms that decouple applications in time, space, synchronization and semantics. Current solutions for decoupled message based communication either do not support message processing and thus semantic decoupling or rely on clearly defined network structures. In this paper we present ASP, a novel concept for such communication that can directly operate on neighbor relations between brokers and does not rely on a homogeneous addressing scheme or anymore than simple link layer communication. We show by simulation that ASP performs well in a heterogeneous scenario with mobile nodes and decreases network or processor load significantly compared to message flooding.

Effects of stochastic noise on dynamical decoupling procedures

NASA Astrophysics Data System (ADS)

Bernád, J. Z.; Frydrych, H.

2014-06-01

Dynamical decoupling is an important tool to counter decoherence and dissipation effects in quantum systems originating from environmental interactions. It has been used successfully in many experiments; however, there is still a gap between fidelity improvements achieved in practice compared to theoretical predictions. We propose a model for imperfect dynamical decoupling based on a stochastic Ito differential equation which could explain the observed gap. We discuss the impact of our model on the time evolution of various quantum systems in finite- and infinite-dimensional Hilbert spaces. Analytical results are given for the limit of continuous control, whereas we present numerical simulations and upper bounds for the case of finite control.

Conditioned invariant subspaces, disturbance decoupling and solutions of rational matrix equations

NASA Technical Reports Server (NTRS)

Li, Z.; Sastry, S. S.

1986-01-01

Conditioned invariant subspaces are introduced both in terms of output injection and in terms of state estimation. Various properties of these subspaces are explored and the problem of disturbance decoupling by output injection (OIP) is defined. It is then shown that OIP is equivalent to the problem of disturbance decoupled estimation as introduced in Willems (1982) and Willems and Commault (1980). Both solvability conditions and a description of solutions for a class of rational matrix equations of the form X(s)M(s) = Q(s) on several ways are given in state-space form. Finally, the problem of output stabilization with respect to a disturbance is briefly addressed.

Manipulator control by exact linearization

NASA Technical Reports Server (NTRS)

Kruetz, K.

1987-01-01

Comments on the application to rigid link manipulators of geometric control theory, resolved acceleration control, operational space control, and nonlinear decoupling theory are given, and the essential unity of these techniques for externally linearizing and decoupling end effector dynamics is discussed. Exploiting the fact that the mass matrix of a rigid link manipulator is positive definite, a consequence of rigid link manipulators belonging to the class of natural physical systems, it is shown that a necessary and sufficient condition for a locally externally linearizing and output decoupling feedback law to exist is that the end effector Jacobian matrix be nonsingular. Furthermore, this linearizing feedback is easy to produce.

An Investigation in the Ames 40- by 80-Foot Wind Tunnel of a YT-56A Turboprop Engine Incorporating a Decoupler and a Controlled-Feathering Device

NASA Technical Reports Server (NTRS)

Rogallo, Vernon L.; Yaggy, Paul F.; McCloud, John L., III

1954-01-01

An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph. It was found that with neither device free to operate, the drag levels realized after power failures at airspeeds above 170 mph would impose vertical tail loads higher than those allowable for the YC-130, the airplane for which the test power package was designed. These levels were reached in approximately one second. The maximum drag realized after power failure was not appreciably altered by the use of the decoupler although the decoupler did put a limit on the duration of the peak drag. The controlled-feathering device maintained a level of essentially zero drag after power failure. The use of the decoupler in the YT-56A engine complicates windmilling air-starting procedures and makes it necessary to place operating restrictions on the engine to assure safe flight at low-power conditions,

Robust Crossfeed Design for Hovering Rotorcraft

NASA Technical Reports Server (NTRS)

Catapang, David R.

1993-01-01

Control law design for rotorcraft fly-by-wire systems normally attempts to decouple angular responses using fixed-gain crossfeeds. This approach can lead to poor decoupling over the frequency range of pilot inputs and increase the load on the feedback loops. In order to improve the decoupling performance, dynamic crossfeeds may be adopted. Moreover, because of the large changes that occur in rotorcraft dynamics due to small changes about the nominal design condition, especially for near-hovering flight, the crossfeed design must be 'robust'. A new low-order matching method is presented here to design robust crossfeed compensators for multi-input, multi-output (MIMO) systems. The technique identifies degrees-of-freedom that can be decoupled using crossfeeds, given an anticipated set of parameter variations for the range of flight conditions of concern. Cross-coupling is then reduced for degrees-of-freedom that can use crossfeed compensation by minimizing off-axis response magnitude average and variance. Results are presented for the analysis of pitch, roll, yaw and heave coupling of the UH-60 Black Hawk helicopter in near-hovering flight. Robust crossfeeds are designed that show significant improvement in decoupling performance and robustness over nominal, single design point, compensators. The design method and results are presented in an easily used graphical format that lends significant physical insight to the design procedure. This plant pre-compensation technique is an appropriate preliminary step to the design of robust feedback control laws for rotorcraft.

On lattice chiral gauge theories

NASA Technical Reports Server (NTRS)

Maiani, L.; Rossi, G. C.; Testa, M.

1991-01-01

The Smit-Swift-Aoki formulation of a lattice chiral gauge theory is presented. In this formulation the Wilson and other non invariant terms in the action are made gauge invariant by the coupling with a nonlinear auxilary scalar field, omega. It is shown that omega decouples from the physical states only if appropriate parameters are tuned so as to satisfy a set of BRST identities. In addition, explicit ghost fields are necessary to ensure decoupling. These theories can give rise to the correct continuum limit. Similar considerations apply to schemes with mirror fermions. Simpler cases with a global chiral symmetry are discussed and it is shown that the theory becomes free at decoupling. Recent numerical simulations agree with those considerations.

Oblique-wing research airplane motion simulation with decoupling control laws

NASA Technical Reports Server (NTRS)

Kempel, Robert W.; Mc Neill, Walter E.; Maine, Trindel A.

1988-01-01

A large piloted vertical motion simulator was used to assess the performance of a preliminary decoupling control law for an early version of the F-8 oblique wing research demonstrator airplane. Evaluations were performed for five discrete flight conditions, ranging from low-altitude subsonic Mach numbers to moderate-altitude supersonic Mach numbers. Asymmetric sideforce as a function of angle of attack was found to be the primary cause of both the lateral acceleration noted in pitch and the tendency to roll into left turns and out of right turns. The flight control system was shown to be effective in generally decoupling the airplane and reducing the lateral acceleration in pitch maneuvers.

Applications of the CAM Based on a New Decoupling Procedure of Correlation Functions in the One-Dimensional Contact Process

NASA Astrophysics Data System (ADS)

Konno, Norio; Katori, Makoto

The one-dimensional contact process (CP) is studied by a systematic series of approximations. A new decoupling procedure of correlation functions is proposed by combining the idea of Suzuki's correlation-identity-decoupling (CID) with a concept of window. Liggett's approximations are also considered. Applying Suzuki's coherent-anomaly method (CAM) to the mean-field-type solutions, the values of the critical point and the critical exponents are estimated as λc = 1.6490(±0.0008), β=0.280(±0.013), Δ(= Δ/δ)= 1.734(±O.OO1), β=0.627(±0.005). Finally a comparison with other estimates is shown.

Applications of the CAM Based on a New Decoupling Procedure of Correlation Functions in the One-Dimensional Contact Process

NASA Astrophysics Data System (ADS)

Konno, Norio; Katori, Makoto

1990-05-01

The one-dimensional contact process (CP) is studied by a systematic series of approximations. A new decoupling procedure of correlation functions is proposed by combining the idea of Suzuki’s correlation-identity-decoupling (CID) with a concept of window. Liggett’s approximations are also considered. Applying Suzuki’s coherent-anomaly method (CAM) to the mean-field-type solutions, the values of the critical point and the critical exponents are estimated as λc{=}1.6490(± 0.0008), β{=}0.280(± 0.013), \\varDelta({=}β/δ){=}1.734(± 0.001), \\hatβ{=}0.627(± 0.005). Finally a comparison with other estimates is shown.

The Female-to-Male Transsexual Voice: Physiology vs. Performance in Production

ERIC Educational Resources Information Center

Papp, Viktoria

2011-01-01

Results of the three studies on the speech production of female-to-male transgender individuals (transmen) present phonetic evidence that speech produces the transmen by what I termed triple decoupling. Transmen successfully decouple gender from biological sex. The results of the longitudinal studies exemplified that speakers born and raised…

Laminar flamelet modeling of turbulent diffusion flames

NASA Technical Reports Server (NTRS)

Mell, W. E.; Kosaly, G.; Planche, O.; Poinsot, T.; Ferziger, J. H.

1990-01-01

In modeling turbulent combustion, decoupling the chemistry from the turbulence is of great practical significance. In cases in which the equilibrium chemistry model breaks down, laminar flamelet modeling (LFM) is a promising approach to decoupling. Here, the validity of this approach is investigated using direct numerical simulation of a simple chemical reaction in two-dimensional turbulence.

Impact of nitrogen reduction measures on nitrogen surplus, income and production of German agriculture.

PubMed

Gömann, H; Kreins, P; Møller, C

2004-01-01

Among the numerous non-point sources of diffuse water pollution with nitrogen, agriculture is counted one of the main sources. The agricultural policies of the Agenda 2000 and a decoupling of direct payments for farmers from their production decisions are exemplarily evaluated as nitrogen reduction measures using the Regional Agricultural and Environmental Information System RAUMIS. The results show that until the target year 2010 the risk of diffuse pollution of water bodies with nitrogen is a regional problem in Germany. These problems are neither mitigated by the policies of Agenda 2000 nor by a decoupling of direct payments from production decisions of farmers. While total nitrogen surplus reduces considerably after a decoupling of direct payments due to decreases of land-use the nitrogen surplus on the remaining cultivated area increases resulting from structural changes. Granting the same amount of direct payments to farmers in both policy alternatives the agricultural sector income would be higher after a decoupling of direct payments opposed to the Agenda 2000 resulting from a more efficient allocation of inputs.

Effect of pressure on decoupling of ionic conductivity from structural relaxation in hydrated protic ionic liquid, lidocaine HCl.

PubMed

Swiety-Pospiech, A; Wojnarowska, Z; Hensel-Bielowka, S; Pionteck, J; Paluch, M

2013-05-28

Broadband dielectric spectroscopy and pressure-temperature-volume methods are employed to investigate the effect of hydrostatic pressure on the conductivity relaxation time (τσ), both in the supercooled and glassy states of protic ionic liquid lidocaine hydrochloride monohydrate. Due to the decoupling between the ion conductivity and structural dynamics, the characteristic change in behavior of τσ(T) dependence, i.e., from Vogel-Fulcher-Tammann-like to Arrhenius-like behavior, is observed. This crossover is a manifestation of the liquid-glass transition of lidocaine HCl. The similar pattern of behavior was also found for pressure dependent isothermal measurements. However, in this case the transition from one simple volume activated law to another was noticed. Additionally, by analyzing the changes of conductivity relaxation times during isothermal densification of the sample, it was found that compression enhances the decoupling of electrical conductivity from the structural relaxation. Herein, we propose a new parameter, dlogRτ∕dP, to quantify the pressure sensitivity of the decoupling phenomenon. Finally, the temperature and volume dependence of τσ is discussed in terms of thermodynamic scaling concept.

Selective coupling of individual electron and nuclear spins with integrated all-spin coherence protection

NASA Astrophysics Data System (ADS)

Terletska, Hanna; Dobrovitski, Viatcheslav

2015-03-01

The electron spin of the NV center in diamond is a promising platform for spin sensing. Applying the dynamical decoupling, the NV electron spin can be used to detect the individual weakly coupled carbon-13 nuclear spins in diamond and employ them for small-scale quantum information processing. However, the nuclear spins within this approach remain unprotected from decoherence, which ultimately limits the detection and restricts the fidelity of the quantum operation. Here we investigate possible schemes for combining the resonant decoupling on the NV spin with the decoherence protection of the nuclear spins. Considering several schemes based on pulse and continuous-wave decoupling, we study how the joint electron-nuclear spin dynamics is affected. We identify regimes where the all-spin coherence protection improves the detection and manipulation. We also discuss potential applications of the all-spin decoupling for detecting spins outside diamond, with the purpose of implementing the nanoscale NMR. This work was supported by the US Department of Energy Basic Energy Sciences (Contract No. DE-AC02-07CH11358).

Second-Order Consensus in Multiagent Systems via Distributed Sliding Mode Control.

PubMed

Yu, Wenwu; Wang, He; Cheng, Fei; Yu, Xinghuo; Wen, Guanghui

2016-11-22

In this paper, the new decoupled distributed sliding-mode control (DSMC) is first proposed for second-order consensus in multiagent systems, which finally solves the fundamental unknown problem for sliding-mode control (SMC) design of coupled networked systems. A distributed full-order sliding-mode surface is designed based on the homogeneity with dilation for reaching second-order consensus in multiagent systems, under which the sliding-mode states are decoupled. Then, the SMC is applied to the decoupled sliding-mode states to reach their origin in finite time, which is the sliding-mode surface. The states of agents can first reach the designed sliding-mode surface in finite time and then move to the second-order consensus state along the surface in finite time as well. The DSMC designed in this paper can eliminate the influence of singularity problems and weaken the influence of chattering, which is still very difficult in the SMC systems. In addition, DSMC proposes a general decoupling framework for designing SMC in networked multiagent systems. Simulations are presented to verify the theoretical results in this paper.

Ruddlesden-Popper interface in correlated manganite heterostructures induces magnetic decoupling and dead layer reduction

NASA Astrophysics Data System (ADS)

Belenchuk, A.; Shapoval, O.; Roddatis, V.; Bruchmann-Bamberg, V.; Samwer, K.; Moshnyaga, V.

2016-12-01

We report on the interface engineering in correlated manganite heterostructures by octahedral decoupling using embedded stacks of atomic layers that form the Ruddlesden-Popper structure. A room temperature magnetic decoupling was achieved through deposition of a (SrO)2-TiO2-(SrO)2 sequence of atomic layers at the interface between La0.7Sr0.3MnO3 and La0.7Sr0.3Mn0.9Ru0.1O3 films. Moreover, the narrowing of the interfacial dead layer in ultrathin La0.7Sr0.3MnO3 films was demonstrated by insertion of a single (SrO)2 rock-salt layer at the interface with the SrTiO3(100) substrate. The obtained results are discussed based on the symmetry breaking and disconnection of the MnO6 octahedra network at the interface that may lead to the improved performance of all-oxide magnetic tunnel junctions. We suggest that octahedral decoupling realized by formation of Ruddlesden-Popper interfaces is an effective structural mechanism to control functionalities of correlated perovskite heterostructures.

Holographic entanglement entropy and entanglement thermodynamics of 'black' non-susy D3 brane

NASA Astrophysics Data System (ADS)

Bhattacharya, Aranya; Roy, Shibaji

2018-06-01

Like BPS D3 brane, the non-supersymmetric (non-susy) D3 brane of type IIB string theory is also known to have a decoupling limit and leads to a non-supersymmetric AdS/CFT correspondence. The throat geometry in this case represents a QFT which is neither conformal nor supersymmetric. The 'black' version of the non-susy D3 brane in the decoupling limit describes a QFT at finite temperature. Here we first compute the entanglement entropy for small subsystem of such QFT from the decoupled geometry of 'black' non-susy D3 brane using holographic technique. Then we study the entanglement thermodynamics for the weakly excited states of this QFT from the asymptotically AdS geometry of the decoupled 'black' non-susy D3 brane. We observe that for small subsystem this background indeed satisfies a first law like relation with a universal (entanglement) temperature inversely proportional to the size of the subsystem and an (entanglement) pressure normal to the entangling surface. Finally we show how the entanglement entropy makes a cross-over to the thermal entropy at high temperature.

Controlling the electronic structure of graphene using surface-adsorbate interactions

DOE PAGES

Matyba, Piotr; Carr, Adra; Chen, Cong; ...

2015-07-15

Hybridization of atomic orbitals in graphene on Ni(111) opens up a large energy gap of ≈2.8eV between nonhybridized states at the K point. Here we use alkali-metal adsorbate to reduce and even eliminate this energy gap, and also identify a new mechanism responsible for decoupling graphene from the Ni substrate without intercalation of atomic species underneath. Using angle-resolved photoemission spectroscopy and density functional theory calculations, we show that the energy gap is reduced to 1.3 eV due to moderate decoupling after adsorption of Na on top of graphene. Calculations confirm that after adsorption of Na, graphene bonding to Ni ismore » much weaker due to a reduced overlap of atomic orbitals, which results from n doping of graphene. Finally, we show that the energy gap is eliminated by strong decoupling resulting in a quasifreestanding graphene, which is achieved by subsequent intercalation of the Na underneath graphene. Furthermore, the ability to partially decouple graphene from a Ni substrate via n doping, with or without intercalation, suggests that the graphene-to-substrate interaction could be controlled dynamically.« less

The neurocognitive consequences of the wandering mind: a mechanistic account of sensory-motor decoupling

PubMed Central

Kam, Julia W. Y.; Handy, Todd C.

2013-01-01

A unique human characteristic is our ability to mind wander – a state in which we are free to engage in thoughts that are not directly tied to sensations and perceptions from our immediate physical environment. From a neurocognitive perspective, it has been proposed that during mind wandering, our executive resources are decoupled from the external environment and directed to these internal thoughts. In this review, we examine an underappreciated aspect of this phenomenon – attenuation of sensory-motor processing – from two perspectives. First, we describe the range of widespread sensory, cognitive and motor processes attenuated during mind wandering states, and how this impacts our neurocognitive processing of external events. We then consider sensory-motor attenuation in a class of clinical neurocognitive disorders that have ties to pathological patterns of decoupling, reviews suggesting that mind wandering and these clinical states may share a common mechanism of sensory-motor attenuation. Taken together, these observations suggest the sensory-motor consequences of decoupled thinking are integral to normal and pathological neurocognitive states. PMID:24133472

Isotopic decoupling during porous melt flow: A case-study in the Lherz peridotite

NASA Astrophysics Data System (ADS)

Le Roux, V.; Bodinier, J.-L.; Alard, O.; O'Reilly, S. Y.; Griffin, W. L.

2009-03-01

Most peridotite massifs and mantle xenoliths show a wide range of isotopic variations, often involving significant decoupling between Hf, Nd and Sr isotopes. These variations are generally ascribed either to mingling of individual components of contrasted isotopic compositions or to time integration of parent-element enrichment by percolating melts/fluids, superimposed onto previous depletion event(s). However, strong isotopic decoupling may also arise during porous flow as a result of daughter-elements fractionation during solid-liquid interaction. Although porous flow is recognized as an important process in mantle rocks, its effects on mantle isotopic variability have been barely investigated so far. The peridotites of the Lherz massif (French Pyrenees) display a frozen melt percolation front separating highly refractory harzburgites from refertilized lherzolites. Isotopic signatures observed at the melt percolation front show a strong decoupling of Hf from Nd and Sr isotopes that cannot be accounted for by simple mixing involving the harzburgite protolith and the percolating melt. Using one dimensional percolation-diffusion and percolation-reaction modeling, we show that these signatures represent transient isotopic compositions generated by porous flow. These signatures are governed by a few critical parameters such as daughter element concentrations in melt and peridotite, element diffusivity, and efficiency of isotopic homogenization rather than by the chromatographic effect of melt transport and the refertilization reaction. Subtle variations in these parameters may generate significant inter-isotopic decoupling and wide isotopic variations in mantle rocks.

Robust crossfeed design for hovering rotorcraft. M.S. Thesis

NASA Technical Reports Server (NTRS)

Catapang, David R.

1993-01-01

Control law design for rotorcraft fly-by-wire systems normally attempts to decouple angular responses using fixed-gain crossfeeds. This approach can lead to poor decoupling over the frequency range of pilot inputs and increase the load on the feedback loops. In order to improve the decoupling performance, dynamic crossfeeds may be adopted. Moreover, because of the large changes that occur in rotorcraft dynamics due to small changes about the nominal design condition, especially for near-hovering flight, the crossfeed design must be 'robust.' A new low-order matching method is presented here to design robost crossfeed compensators for multi-input, multi-output (MIMO) systems. The technique identifies degrees-of-freedom that can be decoupled using crossfeeds, given an anticipated set of parameter variations for the range of flight conditions of concern. Cross-coupling is then reduced for degrees-of-freedom that can use crossfeed compensation by minimizing off-axis response magnitude average and variance. Results are presented for the analysis of pitch, roll, yaw, and heave coupling of the UH-60 Black Hawk helicopter in near-hovering flight. Robust crossfeeds are designed that show significant improvement in decoupling performance and robustness over nominal, single design point, compensators. The design method and results are presented in an easily-used graphical format that lends significant physical insight to the design procedure. This plant pre-compensation technique is an appropriate preliminary step to the design of robust feedback control laws for rotorcraft.

Effects of testosterone administration on threat and escape anticipation in the orbitofrontal cortex.

PubMed

Heany, Sarah J; Bethlehem, Richard A I; van Honk, Jack; Bos, Peter A; Stein, Dan J; Terburg, David

2018-05-30

Recent evidence suggests that the steroid hormone testosterone can decrease the functional coupling between orbitofrontal cortex (OFC) and amygdala. Theoretically this decoupling has been linked to a testosterone-driven increase of goal-directed behaviour in case of threat, but this has never been studied directly. Therefore, we placed twenty-two women in dynamically changing situations of escapable and inescapable threat after a within-subject placebo controlled testosterone administration. Using functional magnetic resonance imaging (fMRI) we provide evidence that testosterone activates the left lateral OFC (LOFC) in preparation of active goal-directed escape and decouples this OFC area from a subcortical threat system including the central-medial amygdala, hypothalamus and periaqueductal gray. This LOFC decoupling was specific to threatening situations, a point that was further emphasized by an absence of such decoupling in a second experiment focused on resting-state connectivity. These results not only confirm that testosterone administration decouples the LOFC from the subcortical threat system, but also show that this is specifically the case in response to acute threat, and ultimately leads to an increase in LOFC activity when the participant prepares a goal-directed action to escape. Together these results for the first time provide a detailed understanding of functional brain alterations induced by testosterone under threat conditions, and corroborate and extend the view that testosterone prepares the brain for goal-directed action in case of threat. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Schizotypal Traits are Linked to Dopamine-Induced Striato-Cortical Decoupling: A Randomized Double-Blind Placebo-Controlled Study.

PubMed

Rössler, Julian; Unterassner, Lui; Wyss, Thomas; Haker, Helene; Brugger, Peter; Rössler, Wulf; Wotruba, Diana

2018-06-07

The dopamine hypothesis of schizophrenia implies that alterations in the dopamine system cause functional abnormalities in the brain that may converge to aberrant salience attribution and eventually lead to psychosis. Indeed, widespread brain disconnectivity across the psychotic spectrum has been revealed by resting-state functional magnetic resonance imaging (rs-fMRI). However, the dopaminergic involvement in intrinsic functional connectivity (iFC) and its putative relationship to the development of psychotic spectrum disorders remains partly unclear-in particular at the low-end of the psychosis continuum. Therefore, we investigated dopamine-induced changes in striatal iFC and their modulation by psychometrically assessed schizotypy. Our randomized, double-blind placebo-controlled study design included 54 healthy, right-handed male participants. Each participant was assessed with the Schizotypal Personality Questionnaire (SPQ) and underwent 10 minutes of rs-fMRI scanning. Participants then received either a placebo or 200 mg of L-DOPA, a dopamine precursor. We analyzed iFC of 6 striatal seeds that are known to evoke modulation of dopamine-related networks. The main effect of L-DOPA was a significant functional decoupling from the right ventral caudate to both occipital fusiform gyri. This dopamine-induced decoupling emerged primarily in participants with low SPQ scores, while participants with high positive SPQ scores showed decoupling indifferently of the L-DOPA challenge. Taken together, these findings demonstrate that schizotypal traits may be the result of dopamine-induced striato-occipital decoupling.

Unmasking decoupling: Redefining the Resource Intensity of the Economy.

PubMed

Bithas, Kostas; Kalimeris, Panos

2018-04-01

Interest in investigating the complex link between resources and developments has revived recently following studies which support striking "dematerialized" growth over the last hundred years or so. This so-called decoupling effect is defined as the declining quantity of resources required for producing one unit of GDP. Decoupling studies adopt aggregate GDP as the measure of the outcome of the economy. However, this outcome is contributed by the total population which differs over time and between countries. A valid comparison should use a comparable, standardized indicator that adjusts for population size. GDP per capita, the income index, defines in monetary terms the ultimate outcome of the economy and is adopted by international organizations as the standard index for comparing economies. The income index approximates, in monetary terms, the welfare produced by the economic system and enjoyed by individuals. Recently developed alternative indexes of welfare lack broad data coverage and have limited empirical application as yet. For this reason and for ensuring direct comparison with the standard decoupling estimates, our study remains within the monetary context. The present paper re-evaluates the resources-economy link from the perspective of "the resources required for the production of one unit of GDP per capita (Income)" and hence evaluates the efficiency of turning resources into the actual outcome of the economic system. Our estimates suggest that the dependence of global economic growth on natural resources has increased by over 60% in the last 110years (1900-2009), contrasting with the prevailing decoupling estimates which suggest a reduction by 63%. We find that the actual decoupling, which began in the mid-1970s in post-industrial economies, is counterbalanced by the intensified resource intensity of several developing economies. Accordingly, in the pursuit of sustainability, the dematerialization target needs to be more clearly incorporated into environmental policies and pervade contemporary economic thinking. Copyright © 2017 Elsevier B.V. All rights reserved.

Patterns of cold-air drainage and microclimate in mid-latitude versus high-latitude mountains: contrasts and implications for climate change (Invited)

NASA Astrophysics Data System (ADS)

Pepin, N. C.

2009-12-01

Predictions of current spatial patterns of climate are difficult in areas of complex relief in all parts of the world, because of the interweaving influences of topography, elevation and aspect. These influences vary temporally as a result of the seasonal and diurnal cycles in radiation balance. In periods of negative energy balance, surface decoupling can occur as cold air drainage develops low-level temperature inversions, and the surface temperature regime beneath the inversion becomes divorced from free atmospheric forcing. Both the spatial scale and temporal persistence of this decoupling vary according to latitude, and although the physical processes that influence inversion formation are similar in polar areas and mid-latitude mountains, the contrasting seasonal and diurnal forcings make the end results very different. Examples are contrasted from detailed field temperature measurements (~50 sites per field area) taken over several years in areas of complex relief in the eastern Pyrenees (~42.5 deg N), the Oregon Cascades (also ~42.5 deg N) and Finnish Lapland (70 deg N and above the Arctic circle). In the former two locations decoupling is mostly diurnally driven, and small-scale topography is important in mediating the effects. Summer decoupling is brief and spatially limited, whereas winter decoupling can be more spatially extensive. There are strong relationships between synoptic conditions, as measured by objective flow indices at the 700 mb level (derived from NCEP/NCAR reanalysis fields) and the patterns of decoupling, which allow us to assess the effects of past and potential future circulation change on spatial patterns of future climate warming. In Finnish Lapland the decoupling regime most clearly approaches the mid-latitude pattern around the equinoxes when there are clear day and night periods. In winter and summer however (the polar night and polar day) with the muting of the diurnal cycle, processes are more poorly understood. Winter cold pools can develop and strengthen over days until eventually they extend over and above the topography. Strangely, there are also indistinct relationships with circulation indices at this time. While build-up can take days, destruction is often immediate and is dynamically forced. In summer, localized decoupling occurs on clear nights even though the sun is above the horizon, but micro-scale patterns are different than in mid-latitudes. The above comparison shows that polar areas are very different in their micro-temperature regimes than mid-latitude mountains and in their relationships of these regimes with circulation. Thus we expect detailed spatial patterns of climate change may be very different in the two regions.

Structural Decoupling between the VET and the Employment Systems: Challenges Manifested in Assessment of Practical Training

ERIC Educational Resources Information Center

Umarik, Meril; Loogma, Krista; Hinno, Krista

2010-01-01

This article aims to analyse how structural decoupling, which is an especially relevant problem for school-based vocational education and training (VET) systems, reveals itself in the assessment of practical training. Niklas Luhmann's social system theory has been applied to the analysis of assessment practices as a communication act between the…

Development of the High-Order Decoupled Direct Method in Three Dimensions for Particulate Matter: Enabling Advanced Sensitivity Analysis in Air Quality Models

EPA Science Inventory

The high-order decoupled direct method in three dimensions for particular matter (HDDM-3D/PM) has been implemented in the Community Multiscale Air Quality (CMAQ) model to enable advanced sensitivity analysis. The major effort of this work is to develop high-order DDM sensitivity...

Preserving flying qubit in single-mode fiber with Knill Dynamical Decoupling (KDD)

NASA Astrophysics Data System (ADS)

Gupta, Manish; Navarro, Erik; Moulder, Todd; Mueller, Jason; Balouchi, Ashkan; Brown, Katherine; Lee, Hwang; Dowling, Jonathan

2015-03-01

The implementation of information-theoretic-crypto protocol is limited by decoherence caused by the birefringence of a single-mode fiber. We propose the Knill dynamical decoupling scheme, implemented using half-wave plates, to minimize decoherence and show that a fidelity greater than 96% can be achieved even in presence of rotation error.

Phosphor doping enhanced c-axis alignment and exchange decoupling of sputtered Co-Pt perpendicular thin films

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

Yang, Bo; Qin, Gaowu, E-mail: qingw@smm.neu.edu.cn; Xiao, Na

2016-04-14

In the present work, Co-23.0 at. % Pt and Co-23.0 at. % Pt-3.67 at. % P thin films with their c-axis perpendicular to the substrate surface were fabricated on a glass substrate by DC magnetron sputtering. X-ray diffraction and transmission electron microscopic analyses demonstrate that the doping of P improves the c-axis alignment and forms P-rich non-magnetic phase at grain boundary areas, the latter resulting in inter-granular exchange decoupling between Co-Pt grains. The improved c-axis alignment and the inter-granular exchange decoupling give rise to the increase of the out of plane coercivity and the squareness of the Co-Pt-P films.

Decoupling suspension controller based on magnetic flux feedback.

PubMed

Zhang, Wenqing; Li, Jie; Zhang, Kun; Cui, Peng

2013-01-01

The suspension module control system model has been established based on MIMO (multiple input and multiple output) state feedback linearization. We have completed decoupling between double suspension points, and the new decoupling method has been applied to CMS04 magnetic suspension vehicle in national mid-low-speed maglev experiment field of Tangshan city in China. Double suspension system model is very accurate for investigating stability property of maglev control system. When magnetic flux signal is taken back to the suspension control system, the suspension module's antijamming capacity for resisting suspension load variety has been proved. Also, the external force interference has been enhanced. As a result, the robustness and stability properties of double-electromagnet suspension control system have been enhanced.

Decoupling Suspension Controller Based on Magnetic Flux Feedback

PubMed Central

Zhang, Wenqing; Li, Jie; Zhang, Kun; Cui, Peng

2013-01-01

The suspension module control system model has been established based on MIMO (multiple input and multiple output) state feedback linearization. We have completed decoupling between double suspension points, and the new decoupling method has been applied to CMS04 magnetic suspension vehicle in national mid-low-speed maglev experiment field of Tangshan city in China. Double suspension system model is very accurate for investigating stability property of maglev control system. When magnetic flux signal is taken back to the suspension control system, the suspension module's antijamming capacity for resisting suspension load variety has been proved. Also, the external force interference has been enhanced. As a result, the robustness and stability properties of double-electromagnet suspension control system have been enhanced. PMID:23844415

A novel anti-windup framework for cascade control systems: an application to underactuated mechanical systems.

PubMed

Mehdi, Niaz; Rehan, Muhammad; Malik, Fahad Mumtaz; Bhatti, Aamer Iqbal; Tufail, Muhammad

2014-05-01

This paper describes the anti-windup compensator (AWC) design methodologies for stable and unstable cascade plants with cascade controllers facing actuator saturation. Two novel full-order decoupling AWC architectures, based on equivalence of the overall closed-loop system, are developed to deal with windup effects. The decoupled architectures have been developed, to formulate the AWC synthesis problem, by assuring equivalence of the coupled and the decoupled architectures, instead of using an analogy, for cascade control systems. A comparison of both AWC architectures from application point of view is provided to consolidate their utilities. Mainly, one of the architecture is better in terms of computational complexity for implementation, while the other is suitable for unstable cascade systems. On the basis of the architectures for cascade systems facing stability and performance degradation problems in the event of actuator saturation, the global AWC design methodologies utilizing linear matrix inequalities (LMIs) are developed. These LMIs are synthesized by application of the Lyapunov theory, the global sector condition and the ℒ2 gain reduction of the uncertain decoupled nonlinear component of the decoupled architecture. Further, an LMI-based local AWC design methodology is derived by utilizing a local sector condition by means of a quadratic Lyapunov function to resolve the windup problem for unstable cascade plants under saturation. To demonstrate effectiveness of the proposed AWC schemes, an underactuated mechanical system, the ball-and-beam system, is considered, and details of the simulation and practical implementation results are described. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Foraging at the wildland–urban interface decouples weather as a driver of recruitment for desert bighorn sheep

USGS Publications Warehouse

Longshore, Kathleen M.; Lowrey, Chris E.; Cummings, Patrick

2016-01-01

A growing number of ungulate populations are living within or near the wildland–urban interface. When resources at the interface are of greater quality than that of adjacent natural habitat, wildlife can be attracted to these developed areas. Little is known about how use of the wildland–urban interface by wildlife may affect vital rates. Under natural conditions, recruitment by desert bighorn sheep (Ovis canadensis nelsoni) correlates with variation in the timing and amount of rainfall that initiates and enhances growth of annual plant species. However, for populations that forage in developed areas, this relationship may become decoupled. In the River Mountains of Nevada, USA, desert bighorn sheep have been feeding in a municipal park at the wildland–urban interface since its establishment in 1985. Approximately one-third of the population now uses the park during summer months when nutritional content of natural forage is low. We hypothesized that use of this municipal area, with its abundant vegetation and water resources, may have decoupled the previous relationship between precipitation and lamb recruitment. We assessed variables known to affect lamb recruitment before (1971–1986) and after (1987–2006) establishment of the park using linear regression models. Our top candidate model for the pre-park period indicated that total November precipitation was the greatest driver of lamb recruitment in this population. After park establishment, this relationship became decoupled because lamb recruitment was no longer driven by weather variables. These results raise questions about the effects of decoupling drivers of population growth and maintaining natural populations near urban areas.

Means-Ends Decoupling and Academic Identities in Ukrainian University after the Revolution of Dignity

ERIC Educational Resources Information Center

Hladchenko, Myroslava; Westerheijden, Don F.

2018-01-01

This article aims to explore the academic identities under the conditions of means-ends decoupling at the nation-state level. For empirical evidence we choose Ukraine. In 2014, after the Revolution of Dignity despite the adoption of the policies aimed to construct academic identities like in the Western universities the intended outcomes were not…

Scalable Database Design of End-Game Model with Decoupled Countermeasure and Threat Information

DTIC Science & Technology

2017-11-01

Threat Information by Decetria Akole and Michael Chen Approved for public release; distribution is unlimited...Scalable Database Design of End-Game Model with Decoupled Countermeasure and Threat Information by Decetria Akole The Thurgood Marshall...for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data

Thermofield duality for higher spin Rindler Gravity

DOE PAGES

Jevicki, Antal; Suzuki, Kenta

2016-02-15

In this paper, we study the Thermo-field realization of the duality between the Rindler-AdS higher spin theory and O(N) vector theory. The CFT represents a decoupled pair of free O(N) vector field theories. It is shown how this decoupled domain CFT is capable of generating the connected Rindler-AdS background with the full set of Higher Spin fields.

Decoupling analysis and socioeconomic drivers of environmental pressure in China.

PubMed

Liang, Sai; Liu, Zhu; Crawford-Brown, Douglas; Wang, Yafei; Xu, Ming

2014-01-21

China's unprecedented change offers a unique opportunity for uncovering relationships between economic growth and environmental pressure. Here we show the trajectories of China's environmental pressure and reveal underlying socioeconomic drivers during 1992-2010. Mining and manufacturing industries are the main contributors to increasing environmental pressure from the producer perspective. Changes in urban household consumption, fixed capital formation, and exports are the main drivers from the consumer perspective. While absolute decoupling is not realized, China has in general achieved relative decoupling between economic growth and environmental pressure. China's decoupling performance has four distinguishable periods, closely aligning with nation-wide major policy adjustments, which indicates significant impact of China's national socioeconomic policies on its environmental pressure. Material intensity change is the main contributor to the mitigation of environmental pressure, except for ammonia nitrogen, solid wastes, aquatic Cu, and aquatic Zn. Production structure change is the largest contributor to mitigate ammonia nitrogen emissions, and final demand structure change is the largest contributor to mitigate emissions of solid wastes, aquatic Cu, and aquatic Zn. We observe materialization trends for China's production structure and final demand structure during 2002-2007. Environmental sustainability can only be achieved by timely technology innovation and changes of production structure and consumption pattern.

Theoretical constraints in the design of multivariable control systems

NASA Technical Reports Server (NTRS)

Rynaski, E. G.; Mook, D. J.

1993-01-01

The theoretical constraints inherent in the design of multivariable control systems were defined and investigated. These constraints are manifested by the system transmission zeros that limit or bound the areas in which closed loop poles and individual transfer function zeros may be placed. These constraints were investigated primarily in the context of system decoupling or non-interaction. It was proven that decoupling requires the placement of closed loop poles at the system transmission zeros. Therefore, the system transmission zeros must be minimum phase to guarantee a stable decoupled system. Once decoupling has been accomplished, the remaining part of the system exhibits transmission zeros at infinity, so nearly complete design freedom is possible in terms of placing both poles and zeros of individual closed loop transfer functions. A general, dynamic inversion model following system architecture was developed that encompasses both the implicit and explicit configuration. Robustness properties are developed along with other attributes of this type of system. Finally, a direct design is developed for the longitudinal-vertical degrees of freedom of aircraft motion to show how a direct lift flap can be used to improve the pitch-heave maneuvering coordination for enhanced flying qualities.

Quantifying the ice-albedo feedback through decoupling

NASA Astrophysics Data System (ADS)

Kravitz, B.; Rasch, P. J.

2017-12-01

The ice-albedo feedback involves numerous individual components, whereby warming induces sea ice melt, inducing reduced surface albedo, inducing increased surface shortwave absorption, causing further warming. Here we attempt to quantify the sea ice albedo feedback using an analogue of the "partial radiative perturbation" method, but where the governing mechanisms are directly decoupled in a climate model. As an example, we can isolate the insulating effects of sea ice on surface energy and moisture fluxes by allowing sea ice thickness to change but fixing Arctic surface albedo, or vice versa. Here we present results from such idealized simulations using the Community Earth System Model in which individual components are successively fixed, effectively decoupling the ice-albedo feedback loop. We isolate the different components of this feedback, including temperature change, sea ice extent/thickness, and air-sea exchange of heat and moisture. We explore the interactions between these different components, as well as the strengths of the total feedback in the decoupled feedback loop, to quantify contributions from individual pieces. We also quantify the non-additivity of the effects of the components as a means of investigating the dominant sources of nonlinearity in the ice-albedo feedback.

Urban infrastructure and natural resource flows: evidence from Cape Town.

PubMed

Hyman, Katherine

2013-09-01

The current economic development trajectory is fundamentally unsustainable. However, decoupling economic growth from excessive natural resource consumption can be adopted as a means to deviate from this current trajectory. Decoupling enables economic growth and human development through non-material growth, without the environmental and social casualties of the incumbent model. Cities are the current and future context for socio development as well as a significant part of the cause and solution to sustainability challenges. Cities account for the majority of production and consumption activities leading to environmental degradation, and they are also the primary location for economic, institutional, and human capital. Innovative responses to global challenges generally emerge during the interaction between these kinds of capital. This paper presents the case of three of Cape Town's resource flows namely; electricity, water and solid waste, as mediated by networked urban infrastructure, to demonstrate the possibility of urban scale decoupling. Conclusions indicate that while decoupling can occur at the city scale, it is unlikely to be sufficient for the realization of sustainable urban development. Purposive interventions are therefore critical for successful, sustainable urban transitions. Copyright © 2013 Elsevier B.V. All rights reserved.

A Chebyshev method for state-to-state reactive scattering using reactant-product decoupling: OH + H2 → H2O + H.

PubMed

Cvitaš, Marko T; Althorpe, Stuart C

2013-08-14

We extend a recently developed wave packet method for computing the state-to-state quantum dynamics of AB + CD → ABC + D reactions [M. T. Cvitaš and S. C. Althorpe, J. Phys. Chem. A 113, 4557 (2009)] to include the Chebyshev propagator. The method uses the further partitioned approach to reactant-product decoupling, which uses artificial decoupling potentials to partition the coordinate space of the reaction into separate reactant, product, and transition-state regions. Separate coordinates and basis sets can then be used that are best adapted to each region. We derive improved Chebyshev partitioning formulas which include Mandelshtam-and-Taylor-type decoupling potentials, and which are essential for the non-unitary discrete variable representations that must be used in 4-atom reactive scattering calculations. Numerical tests on the fully dimensional OH + H2 → H2O + H reaction for J = 0 show that the new version of the method is as efficient as the previously developed split-operator version. The advantages of the Chebyshev propagator (most notably the ease of parallelization for J > 0) can now be fully exploited in state-to-state reactive scattering calculations on 4-atom reactions.

Right-handed neutrinos as the dark radiation: Status and forecasts for the LHC

NASA Astrophysics Data System (ADS)

Anchordoqui, Luis A.; Goldberg, Haim; Steigman, Gary

2013-01-01

Precision data from cosmology (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch) have hinted at the presence of extra relativistic degrees of freedom, the so-called "dark radiation." We present a model independent study to account for the dark radiation by means of the right-handed partners of the three, left-handed, standard model neutrinos. We show that milli-weak interactions of these Dirac states (through their coupling to a TeV-scale Z‧ gauge boson) may allow the νR's to decouple much earlier, at a higher temperature, than their left-handed counterparts. If the νR's decouple during the quark-hadron crossover transition, they are considerably cooler than the νL's and contribute less than 3 extra "equivalent neutrinos" to the early Universe energy density. For decoupling in this transition region, the 3νR generate ΔNν=3(<3, extra relativistic degrees of freedom at BBN and at the CMB epochs. Consistency with present constraints on dark radiation permits us to identify the allowed region in the parameter space of Z‧ masses and couplings. Remarkably, the allowed region is within the range of discovery of LHC14.

Control of large flexible spacecraft by the independent modal-space control method

NASA Technical Reports Server (NTRS)

Meirovitch, L.; Shenar, J.

1984-01-01

The problem of control of a large-order flexible structure in the form of a plate-like lattice by the Independent Modal-Space Control (IMSC) method is presented. The equations of motion are first transformed to the modal space, thus obtaining internal (plant) decoupling of the system. Then, the control laws are designed in the modal space for each mode separately, so that the modal equations of motion are rendered externally (controller) decoupled. This complete decoupling applies both to rigid-body modes and elastic modes. The application of linear optimal control, in conjunction with a quadratic performance index, is first reviewed. A solution for high-order systems is proposed here by the IMSC method, whereby the problem is reduced to a number of modal minimum-fuel problems for the controlled modes.

Decoupling of rotational and translational diffusion in supercooled colloidal fluids

PubMed Central

Edmond, Kazem V.; Elsesser, Mark T.; Hunter, Gary L.; Pine, David J.; Weeks, Eric R.

2012-01-01

We use confocal microscopy to directly observe 3D translational and rotational diffusion of tetrahedral clusters, which serve as tracers in colloidal supercooled fluids. We find that as the colloidal glass transition is approached, translational and rotational diffusion decouple from each other: Rotational diffusion remains inversely proportional to the growing viscosity whereas translational diffusion does not, decreasing by a much lesser extent. We quantify the rotational motion with two distinct methods, finding agreement between these methods, in contrast with recent simulation results. The decoupling coincides with the emergence of non-Gaussian displacement distributions for translation whereas rotational displacement distributions remain Gaussian. Ultimately, our work demonstrates that as the glass transition is approached, the sample can no longer be approximated as a continuum fluid when considering diffusion. PMID:23071311

Conjugate Heat Transfer Study in Hypersonic Flows

NASA Astrophysics Data System (ADS)

Sahoo, Niranjan; Kulkarni, Vinayak; Peetala, Ravi Kumar

2018-04-01

Coupled and decoupled conjugate heat transfer (CHT) studies are carried out to imitate experimental studies for heat transfer measurement in hypersonic flow regime. The finite volume based solvers are used for analyzing the heat interaction between fluid and solid domains. Temperature and surface heat flux signals are predicted by both coupled and decoupled CHT analysis techniques for hypersonic Mach numbers. These two methodologies are also used to study the effect of different wall materials on surface parameters. Effectiveness of these CHT solvers has been verified for the inverse problem of wall heat flux recovery using various techniques reported in the literature. Both coupled and decoupled CHT techniques are seen to be equally useful for prediction of local temperature and heat flux signals prior to the experiments in hypersonic flows.

Numerical study of incommensurate and decoupled phases of spin-1/2 chains with isotropic exchange J 1, J 2 between first and second neighbors

NASA Astrophysics Data System (ADS)

Soos, Zoltán G.; Parvej, Aslam; Kumar, Manoranjan

2016-05-01

The spin-1/2 chain with isotropic exchange J 1, J 2  >  0 between first and second neighbors is frustrated for either sign of J 1 and has a singlet ground state (GS) for J 1/J 2  ⩾  -4. Its rich quantum phase diagram supports gapless, gapped, commensurate (C), incommensurate (IC) and other phases. Critical points J 1/J 2 are evaluated using exact diagonalization and density matrix renormalization group calculations. The wave vector q G of spin correlations is related to GS degeneracy and obtained as the peak of the spin structure factor S(q). Variable q G indicates IC phases in two J 1/J 2 intervals, [-4, -  1.24] and [0.44, 2], and a C-IC point at J 1/J 2  =  2. The decoupled C phase in [-1.24, 0.44] has constant q G  =  π/2, nondegenerate GS, and a lowest triplet state with broken spin density on sublattices of odd and even numbered sites. The lowest triplet and singlet excitations, E m and E σ , are degenerate in finite systems at specific frustration J 1/J 2. Level crossing extrapolates in the thermodynamic limit to the same critical points as q G. The S(q) peak diverges at q G  =  π in the gapless phase with J 1/J 2  >  4.148 and quasi-long-range order (QLRO(π)). S(q) diverges at  ±π/2 in the decoupled phase with QLRO(π/2), but is finite in gapped phases with finite-range correlations. Numerical results and field theory agree at small J 2/J 1 but disagree for the decoupled phase with weak exchange J 1 between sublattices. Two related models are summarized: one has an exact gapless decoupled phase with QLRO(π/2) and no IC phases; the other has a single IC phase without a decoupled phase in between.

Quantum Error Correction

NASA Astrophysics Data System (ADS)

Lidar, Daniel A.; Brun, Todd A.

2013-09-01

Prologue; Preface; Part I. Background: 1. Introduction to decoherence and noise in open quantum systems Daniel Lidar and Todd Brun; 2. Introduction to quantum error correction Dave Bacon; 3. Introduction to decoherence-free subspaces and noiseless subsystems Daniel Lidar; 4. Introduction to quantum dynamical decoupling Lorenza Viola; 5. Introduction to quantum fault tolerance Panos Aliferis; Part II. Generalized Approaches to Quantum Error Correction: 6. Operator quantum error correction David Kribs and David Poulin; 7. Entanglement-assisted quantum error-correcting codes Todd Brun and Min-Hsiu Hsieh; 8. Continuous-time quantum error correction Ognyan Oreshkov; Part III. Advanced Quantum Codes: 9. Quantum convolutional codes Mark Wilde; 10. Non-additive quantum codes Markus Grassl and Martin Rötteler; 11. Iterative quantum coding systems David Poulin; 12. Algebraic quantum coding theory Andreas Klappenecker; 13. Optimization-based quantum error correction Andrew Fletcher; Part IV. Advanced Dynamical Decoupling: 14. High order dynamical decoupling Zhen-Yu Wang and Ren-Bao Liu; 15. Combinatorial approaches to dynamical decoupling Martin Rötteler and Pawel Wocjan; Part V. Alternative Quantum Computation Approaches: 16. Holonomic quantum computation Paolo Zanardi; 17. Fault tolerance for holonomic quantum computation Ognyan Oreshkov, Todd Brun and Daniel Lidar; 18. Fault tolerant measurement-based quantum computing Debbie Leung; Part VI. Topological Methods: 19. Topological codes Héctor Bombín; 20. Fault tolerant topological cluster state quantum computing Austin Fowler and Kovid Goyal; Part VII. Applications and Implementations: 21. Experimental quantum error correction Dave Bacon; 22. Experimental dynamical decoupling Lorenza Viola; 23. Architectures Jacob Taylor; 24. Error correction in quantum communication Mark Wilde; Part VIII. Critical Evaluation of Fault Tolerance: 25. Hamiltonian methods in QEC and fault tolerance Eduardo Novais, Eduardo Mucciolo and Harold Baranger; 26. Critique of fault-tolerant quantum information processing Robert Alicki; References; Index.

Performance Analysis of Several GPS/Galileo Precise Point Positioning Models

PubMed Central

Afifi, Akram; El-Rabbany, Ahmed

2015-01-01

This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada’s GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference. PMID:26102495

Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

PubMed

Afifi, Akram; El-Rabbany, Ahmed

2015-06-19

This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

Reaction monitoring using hyperpolarized NMR with scaling of heteronuclear couplings by optimal tracking

NASA Astrophysics Data System (ADS)

Zhang, Guannan; Schilling, Franz; Glaser, Steffen J.; Hilty, Christian

2016-11-01

Off-resonance decoupling using the method of Scaling of Heteronuclear Couplings by Optimal Tracking (SHOT) enables determination of heteronuclear correlations of chemical shifts in single scan NMR spectra. Through modulation of J-coupling evolution by shaped radio frequency pulses, off resonance decoupling using SHOT pulses causes a user-defined dependence of the observed J-splitting, such as the splitting of 13C peaks, on the chemical shift offset of coupled nuclei, such as 1H. Because a decoupling experiment requires only a single scan, this method is suitable for characterizing on-going chemical reactions using hyperpolarization by dissolution dynamic nuclear polarization (D-DNP). We demonstrate the calculation of [13C, 1H] chemical shift correlations of the carbanionic active sites from hyperpolarized styrene polymerized using sodium naphthalene as an initiator. While off resonance decoupling by SHOT pulses does not enhance the resolution in the same way as a 2D NMR spectrum would, the ability to obtain the correlations in single scans makes this method ideal for determination of chemical shifts in on-going reactions on the second time scale. In addition, we present a novel SHOT pulse that allows to scale J-splittings 50% larger than the respective J-coupling constant. This feature can be used to enhance the resolution of the indirectly detected chemical shift and reduce peak overlap, as demonstrated in a model reaction between p-anisaldehyde and isobutylamine. For both pulses, the accuracy is evaluated under changing signal-to-noise ratios (SNR) of the peaks from reactants and reaction products, with an overall standard deviation of chemical shift differences compared to reference spectra of 0.02 ppm when measured on a 400 MHz NMR spectrometer. Notably, the appearance of decoupling side-bands, which scale with peak intensity, appears to be of secondary importance.

Impact of Canopy Decoupling and Subcanopy Advection on the Annual Carbon Balance of a Boreal Scots Pine Forest as Derived From Eddy Covariance

NASA Astrophysics Data System (ADS)

Jocher, Georg; Marshall, John; Nilsson, Mats B.; Linder, Sune; De Simon, Giuseppe; Hörnlund, Thomas; Lundmark, Tomas; Näsholm, Torgny; Ottosson Löfvenius, Mikaell; Tarvainen, Lasse; Wallin, Göran; Peichl, Matthias

2018-02-01

Apparent net uptake of carbon dioxide (CO2) during wintertime by an ˜ 90 year old Scots pine stand in northern Sweden led us to conduct canopy decoupling and subcanopy advection investigations over an entire year. Eddy covariance (EC) measurements ran simultaneously above and within the forest canopy for that purpose. We used the correlation of above- and below-canopy standard deviation of vertical wind speed (σw) as decoupling indicator. We identified 0.33 m s-1 and 0.06 m s-1 as site-specific σw thresholds for above- and below-canopy coupling during nighttime (global radiation <20 W m-2) and 0.23 m s-1 and 0.06 m s-1 as daytime (global radiation >20 W m-2) σw thresholds. Decoupling occurred in 53% of the annual nighttime and 14% of the annual daytime. The annual net ecosystem exchange (NEE), gross ecosystem exchange (GEE), and ecosystem respiration (Reco) derived via two-level filtered EC data were -357 g C m-2, -1,138 g C m-2, and 781 g C m-2, respectively. In comparison, both single-level friction velocity (u*) and quality filtering resulted in 22% higher NEE, mainly caused by 16% lower Reco. GEE remained similar among filtering regimes. Accounting for changes of CO2 storage across the canopy in the single-level filtered data could only marginally decrease these discrepancies. Consequently, advection appears to be responsible for the major part of this divergence. We conclude that the two-level filter is necessary to adequately address decoupling and subcanopy advection at our site, and we recommend this filter for all forested EC sites.

Meta-awareness, perceptual decoupling and the wandering mind.

PubMed

Schooler, Jonathan W; Smallwood, Jonathan; Christoff, Kalina; Handy, Todd C; Reichle, Erik D; Sayette, Michael A

2011-07-01

Mind wandering (i.e. engaging in cognitions unrelated to the current demands of the external environment) reflects the cyclic activity of two core processes: the capacity to disengage attention from perception (known as perceptual decoupling) and the ability to take explicit note of the current contents of consciousness (known as meta-awareness). Research on perceptual decoupling demonstrates that mental events that arise without any external precedent (known as stimulus independent thoughts) often interfere with the online processing of sensory information. Findings regarding meta-awareness reveal that the mind is only intermittently aware of engaging in mind wandering. These basic aspects of mind wandering are considered with respect to the activity of the default network, the role of executive processes, the contributions of meta-awareness and the functionality of mind wandering. Copyright © 2011 Elsevier Ltd. All rights reserved.

An Effective Semantic Event Matching System in the Internet of Things (IoT) Environment.

PubMed

Alhakbani, Noura; Hassan, Mohammed Mehedi; Ykhlef, Mourad

2017-09-02

IoT sensors use the publish/subscribe model for communication to benefit from its decoupled nature with respect to space, time, and synchronization. Because of the heterogeneity of communicating parties, semantic decoupling is added as a fourth dimension. The added semantic decoupling complicates the matching process and reduces its efficiency. Our proposed algorithm clusters subscriptions and events according to topic and performs the matching process within these clusters, which increases the throughput by reducing the matching time from the range of 16-18 ms to 2-4 ms. Moreover, the accuracy of matching is improved when subscriptions must be fully approximated, as demonstrated by an over 40% increase in F-score results. This work shows the benefit of clustering, as well as the improvement in the matching accuracy and efficiency achieved using this approach.

Ion Thermal Decoupling and Species Separation in Shock-Driven Implosions

DOE PAGES

Rinderknecht, Hans G.; Rosenberg, M. J.; Li, C. K.; ...

2015-01-14

Here, anomalous reduction of the fusion yields by 50% and anomalous scaling of the burn-averaged ion temperatures with the ion-species fraction has been observed for the first time in D 3He-filled shock-driven inertial confinement fusion implosions. Two ion kinetic mechanisms are used to explain the anomalous observations: thermal decoupling of the D and 3He populations and diffusive species separation. The observed insensitivity of ion temperature to a varying deuterium fraction is shown to be a signature of ion thermal decoupling in shock-heated plasmas. The burn-averaged deuterium fraction calculated from the experimental data demonstrates a reduction in the average core deuteriummore » density, as predicted by simulations that use a diffusion model. Accounting for each of these effects in simulations reproduces the observed yield trends.« less

Antiresonance and decoupling in electronic transport through parallel-coupled quantum-dot structures with laterally-coupled Majorana zero modes

NASA Astrophysics Data System (ADS)

Zhang, Ya-Jing; Zhang, Lian-Lian; Jiang, Cui; Gong, Wei-Jiang

2018-02-01

We theoretically investigate the electronic transport through a parallel-coupled multi-quantum-dot system, in which the terminal dots of a one-dimensional quantum-dot chain are embodied in the two arms of an Aharonov-Bohm interferometer. It is found that in the structures of odd(even) dots, all their even(odd) molecular states have opportunities to decouple from the leads, and in this process antiresonance occurs which are accordant with the odd(even)-numbered eigenenergies of the sub-molecule without terminal dots. Next when Majorana zero modes are introduced to couple laterally to the terminal dots, the antiresonance and decoupling phenomena still co-exist in the quantum transport process. Such a result can be helpful in understanding the special influence of Majorana zero mode on the electronic transport through quantum-dot systems.

Synthesis and operation of an FFT-decoupled fixed-order reversed-field pinch plasma control system based on identification data

NASA Astrophysics Data System (ADS)

Olofsson, K. Erik J.; Brunsell, Per R.; Witrant, Emmanuel; Drake, James R.

2010-10-01

Recent developments and applications of system identification methods for the reversed-field pinch (RFP) machine EXTRAP T2R have yielded plasma response parameters for decoupled dynamics. These data sets are fundamental for a real-time implementable fast Fourier transform (FFT) decoupled discrete-time fixed-order strongly stabilizing synthesis as described in this work. Robustness is assessed over the data set by bootstrap calculation of the sensitivity transfer function worst-case H_{\\infty} -gain distribution. Output tracking and magnetohydrodynamic mode m = 1 tracking are considered in the same framework simply as two distinct weighted traces of a performance channel output-covariance matrix as derived from the closed-loop discrete-time Lyapunov equation. The behaviour of the resulting multivariable controller is investigated with dedicated T2R experiments.

Maximizing biodiversity co-benefits under REDD+: a decoupled approach

NASA Astrophysics Data System (ADS)

Potts, Matthew D.; Kelley, Lisa C.; Doll, Hannah M.

2013-06-01

Current debates on biodiversity co-benefits under REDD+ are marked by considerable ambiguity and contention. Nevertheless, REDD+ continues to represent one of the most important opportunities for global biodiversity conservation, and the question of how best to achieve biodiversity co-benefits remains an important one. Thus far, most biodiversity conservation in the context of REDD+ is predicated on the notion that services are co-located on a landscape. In contrast, this letter argues that decoupling biodiversity and carbon services on a landscape through national-level planning is a better approach to biodiversity conservation under REDD+. We discuss the fundamental ecological differences between the two services and use principles of resource economics to demonstrate that a decoupled approach will be more efficient, more flexible, and better able to mobilize sufficient finance for biodiversity conservation than a coupled approach.

Decoupling control of a five-phase fault-tolerant permanent magnet motor by radial basis function neural network inverse

NASA Astrophysics Data System (ADS)

Chen, Qian; Liu, Guohai; Xu, Dezhi; Xu, Liang; Xu, Gaohong; Aamir, Nazir

2018-05-01

This paper proposes a new decoupled control for a five-phase in-wheel fault-tolerant permanent magnet (IW-FTPM) motor drive, in which radial basis function neural network inverse (RBF-NNI) and internal model control (IMC) are combined. The RBF-NNI system is introduced into original system to construct a pseudo-linear system, and IMC is used as a robust controller. Hence, the newly proposed control system incorporates the merits of the IMC and RBF-NNI methods. In order to verify the proposed strategy, an IW-FTPM motor drive is designed based on dSPACE real-time control platform. Then, the experimental results are offered to verify that the d-axis current and the rotor speed are successfully decoupled. Besides, the proposed motor drive exhibits strong robustness even under load torque disturbance.

Centrifugally decoupling touchdown bearings

DOEpatents

Post, Richard F

2014-06-24

Centrifugally decoupling mechanical bearing systems provide thin tensioned metallic ribbons contained in a support structure. This assembly rotates around a stationary shaft being centered at low speeds by the action of the metal ribbons. Tension springs are connected on one end to the ribbons and on the other end to the support structure. The ribbons pass through slots in the inner ring of the support structure. The spring preloading thus insures contact (or near-contact) between the ribbons and the shaft at rotation speeds below the transition speed. Above this speed, however, the centrifugal force on the ribbons produces a tensile force on them that exceeds the spring tensile force so that the ribbons curve outward, effectively decoupling them from mechanical contact with the shaft. They still remain, however, in position to act as a touchdown bearing in case of abnormally high transverse accelerations.

Direct matching methods for coils and preamplifiers in MRI

NASA Astrophysics Data System (ADS)

Cao, Xueming; Fischer, Elmar; Hennig, Jürgen; Zaitsev, Maxim

2018-05-01

In this paper, direct matching methods for coils and preamplifiers in receiver arrays are presented. Instead of compensating the reactance of the input impedance of preamplifiers, in our method, the reactance was used to resonate with the coil matching networks and thus to decouple the coils. Furthermore, coil matching networks and preamplifier input matching networks were combined, meaning the coil loop can be matched to the transistor in the preamplifier directly. These matching methods and, for comparison, the conventional matching method were implemented with custom-made preamplifiers and coils. Decoupling and noise-matching performance were compared between these three configurations. Phase shifting networks between coils and preamplifiers are not necessary in our matching methods. With fewer components, these matching networks showed lower noise factors, while similar preamplifier-decoupling performance was found for all three methods.

Parameter reduction in nonlinear state-space identification of hysteresis

NASA Astrophysics Data System (ADS)

Fakhrizadeh Esfahani, Alireza; Dreesen, Philippe; Tiels, Koen; Noël, Jean-Philippe; Schoukens, Johan

2018-05-01

Recent work on black-box polynomial nonlinear state-space modeling for hysteresis identification has provided promising results, but struggles with a large number of parameters due to the use of multivariate polynomials. This drawback is tackled in the current paper by applying a decoupling approach that results in a more parsimonious representation involving univariate polynomials. This work is carried out numerically on input-output data generated by a Bouc-Wen hysteretic model and follows up on earlier work of the authors. The current article discusses the polynomial decoupling approach and explores the selection of the number of univariate polynomials with the polynomial degree. We have found that the presented decoupling approach is able to reduce the number of parameters of the full nonlinear model up to about 50%, while maintaining a comparable output error level.

Subsonic investigations of vortex interaction control for enhanced high-alpha aerodynamics of a chine forebody/Delta wing configuration

NASA Technical Reports Server (NTRS)

Rao, Dhanvada M.; Bhat, M. K.

1992-01-01

A proposed concept to alleviate high alpha asymmetry and lateral/directional instability by decoupling of forebody and wing vortices was studied on a generic chine forebody/ 60 deg. delta configuration in the NASA Langley 7 by 10 foot High Speed Tunnel. The decoupling technique involved inboard leading edge flaps of varying span and deflection angle. Six component force/moment characteristics, surface pressure distributions and vapor-screen flow visualizations were acquired, on the basic wing-body configuration and with both single and twin vertical tails at M sub infinity = 0.1 and 0.4, and in the range alpha = 0 to 50 deg and beta = -10 to +10 degs. Results are presented which highlight the potential of vortex decoupling via leading edge flaps for enhanced high alpha lateral/directional characteristics.

Coupled and decoupled on-chip solenoid inductors with nanogranular magnetic cores

NASA Astrophysics Data System (ADS)

He, Yuhan; Wang, Luo; Wang, Yicheng; Zhang, Huaiwu; Peng, Dongliang; Bai, Feiming

2017-12-01

On-chip integrated solenoid inductors with multilayered nanogranular magnetic cores have been designed and fabricated on silicon wafers. Both decoupled and coupled inductors with multilayered magnetic cores were studied. For the decoupled inductor, an inductance of 14.2 nH or an equivalent inductance area density greater than 100 nH/mm2 was obtained, which is about 14 times of that of the air-core inductor, and the quality factor is 7.5 at 130 MHz. For the coupled inductor, an even higher peak quality factor of 17 was achieved at 300 MHz, however, the inductance area density decreased to 34 nH/mm2. The reason of the enhanced peak quality factor was attributed to less spike domains on the edge of the closure-loop shaped magnetic core, and therefore higher permeability and more uniform uniaxial anisotropy.

The influence of surface versus free-air decoupling on temperature trend patterns in the western United States

Treesearch

N.C. Pepin; C. Daly; J. Lundquist

2011-01-01

We analyzed temperature trends from 460 GHCNv2 weather stations in the western United States for 1948¨C2006 to determine whether the extent of decoupling of surface temperatures from the free atmosphere influences past change. At each location we derived monthly indices representative of anticyclonicity using NCEP/NCAR 700 hPa reanalysis pressure fields. The number of...

Elastically Decoupling Dark Matter.

PubMed

Kuflik, Eric; Perelstein, Maxim; Lorier, Nicolas Rey-Le; Tsai, Yu-Dai

2016-06-03

We present a novel dark matter candidate, an elastically decoupling relic, which is a cold thermal relic whose present abundance is determined by the cross section of its elastic scattering on standard model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross section with electrons, photons and/or neutrinos in the 10^{-3}-1  fb range.

Bearing Survivability and Friction Determination for Fuze Decoupling Applications

DTIC Science & Technology

2012-09-01

three types of ball bearings. The revolutions per minute versus time plots acquired from spin-down trials provide a qualitative view of bearing...ACKNOWLEDGMENTS The Dragon Bearing Team would like to thank Jason DeVenezia and Michael Hollis for their assistance in developing test fixtures...Optimized Navigation ( DRAGON ) program, the bearings would be used to decouple the fuze from the remainder of the body to mitigate drive actuation

Accelerated plate tectonics.

PubMed

Anderson, D L

1975-03-21

The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

Quadrature transmit coil for breast imaging at 7 tesla using forced current excitation for improved homogeneity.

PubMed

McDougall, Mary Preston; Cheshkov, Sergey; Rispoli, Joseph; Malloy, Craig; Dimitrov, Ivan; Wright, Steven M

2014-11-01

To demonstrate the use of forced current excitation (FCE) to create homogeneous excitation of the breast at 7 tesla, insensitive to the effects of asymmetries in the electrical environment. FCE was implemented on two breast coils: one for quadrature (1) H imaging and one for proton-decoupled (13) C spectroscopy. Both were a Helmholtz-saddle combination, with the saddle tuned to 298 MHz for imaging and 75 MHz for spectroscopy. Bench measurements were acquired to demonstrate the ability to force equal currents on elements in the presence of asymmetric loading to improve homogeneity. Modeling and temperature measurements were conducted per safety protocol. B1 mapping, imaging, and proton-decoupled (13) C spectroscopy were demonstrated in vivo. Using FCE to ensure balanced currents on elements enabled straightforward tuning and maintaining of isolation between quadrature elements of the coil. Modeling and bench measurements confirmed homogeneity of the field, which resulted in images with excellent fat suppression and in broadband proton-decoupled carbon-13 spectra. FCE is a straightforward approach to ensure equal currents on multiple coil elements and a homogeneous excitation field, insensitive to the effects of asymmetries in the electrical environment. This enabled effective breast imaging and proton-decoupled carbon-13 spectroscopy at 7T. © 2014 Wiley Periodicals, Inc.

Dynamic decoupling and local atomic order of a model multicomponent metallic glass-former.

PubMed

Kim, Jeongmin; Sung, Bong June

2015-06-17

The dynamics of multicomponent metallic alloys is spatially heterogeneous near glass transition. The diffusion coefficient of one component of the metallic alloys may also decouple from those of other components, i.e., the diffusion coefficient of each component depends differently on the viscosity of metallic alloys. In this work we investigate the dynamic heterogeneity and decoupling of a model system for multicomponent Pd43Cu27Ni10P20 melts by using a hard sphere model that considers the size disparity of alloys but does not take chemical effects into account. We also study how such dynamic behaviors would relate to the local atomic structure of metallic alloys. We find, from molecular dynamics simulations, that the smallest component P of multicomponent Pd43Cu27Ni10P20 melts becomes dynamically heterogeneous at a translational relaxation time scale and that the largest major component Pd forms a slow subsystem, which has been considered mainly responsible for the stabilization of amorphous state of alloys. The heterogeneous dynamics of P atoms accounts for the breakdown of Stokes-Einstein relation and also leads to the dynamic decoupling of P and Pd atoms. The dynamically heterogeneous P atoms decrease the lifetime of the local short-range atomic orders of both icosahedral and close-packed structures by orders of magnitude.

Massive Fermi gas in the expanding universe

NASA Astrophysics Data System (ADS)

Trautner, Andreas

2017-03-01

The behavior of a decoupled ideal Fermi gas in a homogeneously expanding three-dimensional volume is investigated, starting from an equilibrium spectrum. In case the gas is massless and/or completely degenerate, the spectrum of the gas can be described by an effective temperature and/or an effective chemical potential, both of which scale down with the volume expansion. In contrast, the spectrum of a decoupled massive and non-degenerate gas can only be described by an effective temperature if there are strong enough self-interactions such as to maintain an equilibrium distribution. Assuming perpetual equilibration, we study a decoupled gas which is relativistic at decoupling and then is red-shifted until it becomes non-relativistic. We find expressions for the effective temperature and effective chemical potential which allow us to calculate the final spectrum for arbitrary initial conditions. This calculation is enabled by a new expansion of the Fermi-Dirac integral, which is for our purpose superior to the well-known Sommerfeld expansion. We also compute the behavior of the phase space density under expansion and compare it to the case of real temperature and real chemical potential. Using our results for the degenerate case, we also obtain the mean relic velocity of the recently proposed non-thermal cosmic neutrino background.

Inverse dynamic substructuring using the direct hybrid assembly in the frequency domain

NASA Astrophysics Data System (ADS)

D'Ambrogio, Walter; Fregolent, Annalisa

2014-04-01

The paper deals with the identification of the dynamic behaviour of a structural subsystem, starting from the known dynamic behaviour of both the coupled system and the remaining part of the structural system (residual subsystem). This topic is also known as decoupling problem, subsystem subtraction or inverse dynamic substructuring. Whenever it is necessary to combine numerical models (e.g. FEM) and test models (e.g. FRFs), one speaks of experimental dynamic substructuring. Substructure decoupling techniques can be classified as inverse coupling or direct decoupling techniques. In inverse coupling, the equations describing the coupling problem are rearranged to isolate the unknown substructure instead of the coupled structure. On the contrary, direct decoupling consists in adding to the coupled system a fictitious subsystem that is the negative of the residual subsystem. Starting from a reduced version of the 3-field formulation (dynamic equilibrium using FRFs, compatibility and equilibrium of interface forces), a direct hybrid assembly is developed by requiring that both compatibility and equilibrium conditions are satisfied exactly, either at coupling DoFs only, or at additional internal DoFs of the residual subsystem. Equilibrium and compatibility DoFs might not be the same: this generates the so-called non-collocated approach. The technique is applied using experimental data from an assembled system made by a plate and a rigid mass.

Urban land use decouples plant-herbivore-parasitoid interactions at multiple spatial scales.

PubMed

Nelson, Amanda E; Forbes, Andrew A

2014-01-01

Intense urban and agricultural development alters habitats, increases fragmentation, and may decouple trophic interactions if plants or animals cannot disperse to needed resources. Specialist insects represent a substantial proportion of global biodiversity and their fidelity to discrete microhabitats provides a powerful framework for investigating organismal responses to human land use. We sampled site occupancy and densities for two plant-herbivore-parasitoid systems from 250 sites across a 360 km2 urban/agricultural landscape to ask whether and how human development decouples interactions between trophic levels. We compared patterns of site occupancy, host plant density, herbivory and parasitism rates of insects at two trophic levels with respect to landcover at multiple spatial scales. Geospatial analyses were used to identify landcover characters predictive of insect distributions. We found that herbivorous insect densities were decoupled from host tree densities in urban landcover types at several spatial scales. This effect was amplified for the third trophic level in one of the two insect systems: despite being abundant regionally, a parasitoid species was absent from all urban/suburban landcover even where its herbivore host was common. Our results indicate that human land use patterns limit distributions of specialist insects. Dispersal constraints associated with urban built development are specifically implicated as a limiting factor.

Urban Land Use Decouples Plant-Herbivore-Parasitoid Interactions at Multiple Spatial Scales

PubMed Central

Nelson, Amanda E.; Forbes, Andrew A.

2014-01-01

Intense urban and agricultural development alters habitats, increases fragmentation, and may decouple trophic interactions if plants or animals cannot disperse to needed resources. Specialist insects represent a substantial proportion of global biodiversity and their fidelity to discrete microhabitats provides a powerful framework for investigating organismal responses to human land use. We sampled site occupancy and densities for two plant-herbivore-parasitoid systems from 250 sites across a 360 km2 urban/agricultural landscape to ask whether and how human development decouples interactions between trophic levels. We compared patterns of site occupancy, host plant density, herbivory and parasitism rates of insects at two trophic levels with respect to landcover at multiple spatial scales. Geospatial analyses were used to identify landcover characters predictive of insect distributions. We found that herbivorous insect densities were decoupled from host tree densities in urban landcover types at several spatial scales. This effect was amplified for the third trophic level in one of the two insect systems: despite being abundant regionally, a parasitoid species was absent from all urban/suburban landcover even where its herbivore host was common. Our results indicate that human land use patterns limit distributions of specialist insects. Dispersal constraints associated with urban built development are specifically implicated as a limiting factor. PMID:25019962

Massive Fermi gas in the expanding universe

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

Trautner, Andreas, E-mail: atrautner@uni-bonn.de

The behavior of a decoupled ideal Fermi gas in a homogeneously expanding three-dimensional volume is investigated, starting from an equilibrium spectrum. In case the gas is massless and/or completely degenerate, the spectrum of the gas can be described by an effective temperature and/or an effective chemical potential, both of which scale down with the volume expansion. In contrast, the spectrum of a decoupled massive and non-degenerate gas can only be described by an effective temperature if there are strong enough self-interactions such as to maintain an equilibrium distribution. Assuming perpetual equilibration, we study a decoupled gas which is relativistic atmore » decoupling and then is red-shifted until it becomes non-relativistic. We find expressions for the effective temperature and effective chemical potential which allow us to calculate the final spectrum for arbitrary initial conditions. This calculation is enabled by a new expansion of the Fermi-Dirac integral, which is for our purpose superior to the well-known Sommerfeld expansion. We also compute the behavior of the phase space density under expansion and compare it to the case of real temperature and real chemical potential. Using our results for the degenerate case, we also obtain the mean relic velocity of the recently proposed non-thermal cosmic neutrino background.« less

High magnetic field ohmically decoupled non-contact technology

DOEpatents

Wilgen, John [Oak Ridge, TN; Kisner, Roger [Knoxville, TN; Ludtka, Gerard [Oak Ridge, TN; Ludtka, Gail [Oak Ridge, TN; Jaramillo, Roger [Knoxville, TN

2009-05-19

Methods and apparatus are described for high magnetic field ohmically decoupled non-contact treatment of conductive materials in a high magnetic field. A method includes applying a high magnetic field to at least a portion of a conductive material; and applying an inductive magnetic field to at least a fraction of the conductive material to induce a surface current within the fraction of the conductive material, the surface current generating a substantially bi-directional force that defines a vibration. The high magnetic field and the inductive magnetic field are substantially confocal, the fraction of the conductive material is located within the portion of the conductive material and ohmic heating from the surface current is ohmically decoupled from the vibration. An apparatus includes a high magnetic field coil defining an applied high magnetic field; an inductive magnetic field coil coupled to the high magnetic field coil, the inductive magnetic field coil defining an applied inductive magnetic field; and a processing zone located within both the applied high magnetic field and the applied inductive magnetic field. The high magnetic field and the inductive magnetic field are substantially confocal, and ohmic heating of a conductive material located in the processing zone is ohmically decoupled from a vibration of the conductive material.

Graphical Representation and Origin of Piezoresistance Effect in Germanium

NASA Astrophysics Data System (ADS)

Matsuda, K.; Nagaoka, S.; Kanda, Y.

2017-06-01

The longitudinal and transverse piezoresistance coefficients of Ge at room temperature are represented graphically as a function of the crystal directions for orientation (001), (110) and (211) planes. Many valley model of conduction band and stress decoupling decoupling of the degenerate valence band into two bands of prolate and oblate ellipsoidal energy surface are shown to explain origin of the piezoresistance. One this basis, comparison between piezoresistance coefficient and theoretical model is discussed.

Life cycles, fitness decoupling and the evolution of multicellularity.

PubMed

Hammerschmidt, Katrin; Rose, Caroline J; Kerr, Benjamin; Rainey, Paul B

2014-11-06

Cooperation is central to the emergence of multicellular life; however, the means by which the earliest collectives (groups of cells) maintained integrity in the face of destructive cheating types is unclear. One idea posits cheats as a primitive germ line in a life cycle that facilitates collective reproduction. Here we describe an experiment in which simple cooperating lineages of bacteria were propagated under a selective regime that rewarded collective-level persistence. Collectives reproduced via life cycles that either embraced, or purged, cheating types. When embraced, the life cycle alternated between phenotypic states. Selection fostered inception of a developmental switch that underpinned the emergence of collectives whose fitness, during the course of evolution, became decoupled from the fitness of constituent cells. Such development and decoupling did not occur when groups reproduced via a cheat-purging regime. Our findings capture key events in the evolution of Darwinian individuality during the transition from single cells to multicellularity.

Decoupling optical function and geometrical form using conformal flexible dielectric metasurfaces

NASA Astrophysics Data System (ADS)

Kamali, Seyedeh Mahsa; Arbabi, Amir; Arbabi, Ehsan; Horie, Yu; Faraon, Andrei

2016-05-01

Physical geometry and optical properties of objects are correlated: cylinders focus light to a line, spheres to a point and arbitrarily shaped objects introduce optical aberrations. Multi-functional components with decoupled geometrical form and optical function are needed when specific optical functionalities must be provided while the shapes are dictated by other considerations like ergonomics, aerodynamics or aesthetics. Here we demonstrate an approach for decoupling optical properties of objects from their physical shape using thin and flexible dielectric metasurfaces which conform to objects' surface and change their optical properties. The conformal metasurfaces are composed of silicon nano-posts embedded in a polymer substrate that locally modify near-infrared (λ=915 nm) optical wavefronts. As proof of concept, we show that cylindrical lenses covered with metasurfaces can be transformed to function as aspherical lenses focusing light to a point. The conformal metasurface concept is highly versatile for developing arbitrarily shaped multi-functional optical devices.

Computing Systemic Risk Using Multiple Behavioral and Keystone Networks: The Emergence of a Crisis in Primate Societies and Banks*

PubMed Central

Fushing, Hsieh; Jordà, Òscar; Beisner, Brianne; McCowan, Brenda

2015-01-01

What do the behavior of monkeys in captivity and the financial system have in common? The nodes in such social systems relate to each other through multiple and keystone networks, not just one network. Each network in the system has its own topology, and the interactions among the system’s networks change over time. In such systems, the lead into a crisis appears to be characterized by a decoupling of the networks from the keystone network. This decoupling can also be seen in the crumbling of the keystone’s power structure toward a more horizontal hierarchy. This paper develops nonparametric methods for describing the joint model of the latent architecture of interconnected networks in order to describe this process of decoupling, and hence provide an early warning system of an impending crisis. PMID:26056422

An Analysis of Polynomial Chaos Approximations for Modeling Single-Fluid-Phase Flow in Porous Medium Systems

PubMed Central

Rupert, C.P.; Miller, C.T.

2008-01-01

We examine a variety of polynomial-chaos-motivated approximations to a stochastic form of a steady state groundwater flow model. We consider approaches for truncating the infinite dimensional problem and producing decoupled systems. We discuss conditions under which such decoupling is possible and show that to generalize the known decoupling by numerical cubature, it would be necessary to find new multivariate cubature rules. Finally, we use the acceleration of Monte Carlo to compare the quality of polynomial models obtained for all approaches and find that in general the methods considered are more efficient than Monte Carlo for the relatively small domains considered in this work. A curse of dimensionality in the series expansion of the log-normal stochastic random field used to represent hydraulic conductivity provides a significant impediment to efficient approximations for large domains for all methods considered in this work, other than the Monte Carlo method. PMID:18836519

High effective inverse dynamics modelling for dual-arm robot

NASA Astrophysics Data System (ADS)

Shen, Haoyu; Liu, Yanli; Wu, Hongtao

2018-05-01

To deal with the problem of inverse dynamics modelling for dual arm robot, a recursive inverse dynamics modelling method based on decoupled natural orthogonal complement is presented. In this model, the concepts and methods of Decoupled Natural Orthogonal Complement matrices are used to eliminate the constraint forces in the Newton-Euler kinematic equations, and the screws is used to express the kinematic and dynamics variables. On this basis, the paper has developed a special simulation program with symbol software of Mathematica and conducted a simulation research on the a dual-arm robot. Simulation results show that the proposed method based on decoupled natural orthogonal complement can save an enormous amount of CPU time that was spent in computing compared with the recursive Newton-Euler kinematic equations and the results is correct and reasonable, which can verify the reliability and efficiency of the method.

Decentralized control of large flexible structures by joint decoupling

NASA Technical Reports Server (NTRS)

Su, Tzu-Jeng; Juang, Jer-Nan

1994-01-01

This paper presents a novel method to design decentralized controllers for large complex flexible structures by using the idea of joint decoupling. Decoupling of joint degrees of freedom from the interior degrees of freedom is achieved by setting the joint actuator commands to cancel the internal forces exerting on the joint degrees of freedom. By doing so, the interactions between substructures are eliminated. The global structure control design problem is then decomposed into several substructure control design problems. Control commands for interior actuators are set to be localized state feedback using decentralized observers for state estimation. The proposed decentralized controllers can operate successfully at the individual substructure level as well as at the global structure level. Not only control design but also control implementation is decentralized. A two-component mass-spring-damper system is used as an example to demonstrate the proposed method.

Fractional Control of An Active Four-wheel-steering Vehicle

NASA Astrophysics Data System (ADS)

Wang, Tianting; Tong, Jun; Chen, Ning; Tian, Jie

2018-03-01

A four-wheel-steering (4WS) vehicle model and reference model with a drop filter are constructed. The decoupling of 4WS vehicle model is carried out. And a fractional PIλDμ controller is introduced into the decoupling strategy to reduce the effects of the uncertainty of the vehicle parameters as well as the unmodelled dynamics on the system performance. Based on optimization techniques, the design of fractional controller are obtained to ensure the robustness of 4WS vehicle during the special range of frequencies through proper choice of the constraints. In order to compare with fractional robust controller, an optimal controller for the same vehicle is also designed. The simulations of the two control systems are carried out and it reveals that the decoupling and fractional robust controller is able to make vehicle model trace the reference model very well with better robustness.

Movement decoupling control for two-axis fast steering mirror

NASA Astrophysics Data System (ADS)

Wang, Rui; Qiao, Yongming; Lv, Tao

2017-02-01

Based on flexure hinge and piezoelectric actuator of two-axis fast steering mirror is a complex system with time varying, uncertain and strong coupling. It is extremely difficult to achieve high precision decoupling control with the traditional PID control method. The feedback error learning method was established an inverse hysteresis model which was based inner product dynamic neural network nonlinear and no-smooth for piezo-ceramic. In order to improve the actuator high precision, a method was proposed, which was based piezo-ceramic inverse model of two dynamic neural network adaptive control. The experiment result indicated that, compared with two neural network adaptive movement decoupling control algorithm, static relative error is reduced from 4.44% to 0.30% and coupling degree is reduced from 12.71% to 0.60%, while dynamic relative error is reduced from 13.92% to 2.85% and coupling degree is reduced from 2.63% to 1.17%.

General solution to inhomogeneous dephasing and smooth pulse dynamical decoupling

NASA Astrophysics Data System (ADS)

Zeng, Junkai; Deng, Xiu-Hao; Russo, Antonio; Barnes, Edwin

2018-03-01

In order to achieve the high-fidelity quantum control needed for a broad range of quantum information technologies, reducing the effects of noise and system inhomogeneities is an essential task. It is well known that a system can be decoupled from noise or made insensitive to inhomogeneous dephasing dynamically by using carefully designed pulse sequences based on square or delta-function waveforms such as Hahn spin echo or CPMG. However, such ideal pulses are often challenging to implement experimentally with high fidelity. Here, we uncover a new geometrical framework for visualizing all possible driving fields, which enables one to generate an unlimited number of smooth, experimentally feasible pulses that perform dynamical decoupling or dynamically corrected gates to arbitrarily high order. We demonstrate that this scheme can significantly enhance the fidelity of single-qubit operations in the presence of noise and when realistic limitations on pulse rise times and amplitudes are taken into account.

Decoupled ARX and RBF Neural Network Modeling Using PCA and GA Optimization for Nonlinear Distributed Parameter Systems.

PubMed

Zhang, Ridong; Tao, Jili; Lu, Renquan; Jin, Qibing

2018-02-01

Modeling of distributed parameter systems is difficult because of their nonlinearity and infinite-dimensional characteristics. Based on principal component analysis (PCA), a hybrid modeling strategy that consists of a decoupled linear autoregressive exogenous (ARX) model and a nonlinear radial basis function (RBF) neural network model are proposed. The spatial-temporal output is first divided into a few dominant spatial basis functions and finite-dimensional temporal series by PCA. Then, a decoupled ARX model is designed to model the linear dynamics of the dominant modes of the time series. The nonlinear residual part is subsequently parameterized by RBFs, where genetic algorithm is utilized to optimize their hidden layer structure and the parameters. Finally, the nonlinear spatial-temporal dynamic system is obtained after the time/space reconstruction. Simulation results of a catalytic rod and a heat conduction equation demonstrate the effectiveness of the proposed strategy compared to several other methods.

Analysis and decoupling control of a permanent magnet spherical actuator.

PubMed

Zhang, Liang; Chen, Weihai; Liu, Jingmeng; Wu, Xingming

2013-12-01

This paper presents the analysis and decoupling control of a spherical actuator, which is capable of performing three degree-of-freedom motion in one joint. The proposed actuator consists of a rotor with multiple PM (Permanent Magnet) poles in a circle and a stator with circumferential coils in three layers. Based on this actuator design, a decoupling control approach is developed. Unlike existing control methods that each coil is responsible for both the spinning and tilting motion, the proposed control strategy specifies the function of each coil. Specifically, the spinning motion is governed by the middle layer coils with a step control approach; while the tilting motion is regulated by upper and lower coils with a computed torque control method. Experiments have been conducted on the prototype to verify the validity of the design procedure, and the experimental results demonstrate the effectiveness of the analysis and control strategy.

Decoupling PI Controller Design for a Normal Conducting RF Cavity Using a Recursive LEVENBERG-MARQUARDT Algorithm

NASA Astrophysics Data System (ADS)

Kwon, Sung-il; Lynch, M.; Prokop, M.

2005-02-01

This paper addresses the system identification and the decoupling PI controller design for a normal conducting RF cavity. Based on the open-loop measurement data of an SNS DTL cavity, the open-loop system's bandwidths and loop time delays are estimated by using batched least square. With the identified system, a PI controller is designed in such a way that it suppresses the time varying klystron droop and decouples the In-phase and Quadrature of the cavity field. The Levenberg-Marquardt algorithm is applied for nonlinear least squares to obtain the optimal PI controller parameters. The tuned PI controller gains are downloaded to the low-level RF system by using channel access. The experiment of the closed-loop system is performed and the performance is investigated. The proposed tuning method is running automatically in real time interface between a host computer with controller hardware through ActiveX Channel Access.

An Effective Semantic Event Matching System in the Internet of Things (IoT) Environment

PubMed Central

Alhakbani, Noura; Ykhlef, Mourad

2017-01-01

IoT sensors use the publish/subscribe model for communication to benefit from its decoupled nature with respect to space, time, and synchronization. Because of the heterogeneity of communicating parties, semantic decoupling is added as a fourth dimension. The added semantic decoupling complicates the matching process and reduces its efficiency. Our proposed algorithm clusters subscriptions and events according to topic and performs the matching process within these clusters, which increases the throughput by reducing the matching time from the range of 16–18 ms to 2–4 ms. Moreover, the accuracy of matching is improved when subscriptions must be fully approximated, as demonstrated by an over 40% increase in F-score results. This work shows the benefit of clustering, as well as the improvement in the matching accuracy and efficiency achieved using this approach. PMID:28869508

Design of an adaptive super-twisting decoupled terminal sliding mode control scheme for a class of fourth-order systems.

PubMed

Ashtiani Haghighi, Donya; Mobayen, Saleh

2018-04-01

This paper proposes an adaptive super-twisting decoupled terminal sliding mode control technique for a class of fourth-order systems. The adaptive-tuning law eliminates the requirement of the knowledge about the upper bounds of external perturbations. Using the proposed control procedure, the state variables of cart-pole system are converged to decoupled terminal sliding surfaces and their equilibrium points in the finite time. Moreover, via the super-twisting algorithm, the chattering phenomenon is avoided without affecting the control performance. The numerical results demonstrate the high stabilization accuracy and lower performance indices values of the suggested method over the other ones. The simulation results on the cart-pole system as well as experimental validations demonstrate that the proposed control technique exhibits a reasonable performance in comparison with the other methods. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

A Galerkin least squares approach to viscoelastic flow.

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

Rao, Rekha R.; Schunk, Peter Randall

2015-10-01

A Galerkin/least-squares stabilization technique is applied to a discrete Elastic Viscous Stress Splitting formulation of for viscoelastic flow. From this, a possible viscoelastic stabilization method is proposed. This method is tested with the flow of an Oldroyd-B fluid past a rigid cylinder, where it is found to produce inaccurate drag coefficients. Furthermore, it fails for relatively low Weissenberg number indicating it is not suited for use as a general algorithm. In addition, a decoupled approach is used as a way separating the constitutive equation from the rest of the system. A Pressure Poisson equation is used when the velocity andmore » pressure are sought to be decoupled, but this fails to produce a solution when inflow/outflow boundaries are considered. However, a coupled pressure-velocity equation with a decoupled constitutive equation is successful for the flow past a rigid cylinder and seems to be suitable as a general-use algorithm.« less

Conservatism, institutionalism, and the social control of intergroup conflict.

PubMed

King, Ryan D

2008-03-01

This research investigates the state social control of intergroup conflict by assessing the sociopolitical determinants of hate crime prosecutions. Consistent with insights from the political sociology of punishment, group-threat accounts of intergroup relations and the state, and neoinstitutional theory, the findings suggest that hate crime prosecutions are fewer where political conservatism, Christian fundamentalism, and black population size are higher, although this last effect is nonlinear. Linkages between district attorneys' offices and communities, on the other hand, increase hate crime prosecutions and the likelihood of offices' creating hate crime policies. Yet these policies are sometimes decoupled from actual enforcement, and such decoupling is more likely in politically conservative districts. The results indicate that common correlates of criminal punishment have very different effects on types of state social control that are protective of minority groups, and also suggest conditions under which policy and practice become decoupled in organizational settings.

Constraints on the subsurface structure of Europa

NASA Astrophysics Data System (ADS)

Golombek, M. P.; Banerdt, W. B.

1990-02-01

The wedge-shaped bands appearing near the anti-Jovian point on Europa are tension cracks which, after formation on an intact lithosphere, have facilitated the rotation of ice-lithosphere sections decoupled from the silicate interior. Such factors as fluid pressure, surface temperature, silicate impurities in the ice, and strain rates, would have affected the processes in question. A minimum degree of differentiation is required for Europa to mechanically decouple the rotated ice lithosphere from the underlying, predominantly silicate mantle.

A Proposal to Develop and Test a Fibre-Optic Coupled Solar Thermal Propulsion System for Microsatellites

DTIC Science & Technology

2006-03-01

high numerical aperture fibre optics. Applying fibre optics to STP allows the solar concentrator mirror to be mechanically decoupled from the solar...Applying fibre optics to STP allows the solar concentrator mirror to be mechanically decoupled from the solar heat exchanger as well as granting...concentration is achieved via an optical concentrating system, such as a series of lenses or mirrors . This concentrated sunlight impinges on a blackbody

Module theoretic zero structures for system matrices

NASA Technical Reports Server (NTRS)

Wyman, Bostwick F.; Sain, Michael K.

1987-01-01

The coordinate-free module-theoretic treatment of transmission zeros for MIMO transfer functions developed by Wyman and Sain (1981) is generalized to include noncontrollable and nonobservable linear dynamical systems. Rational, finitely-generated-modular, and torsion-divisible interpretations of the Rosenbrock system matrix are presented; Gamma-zero and Omega-zero modules are defined and shown to contain the output-decoupling and input-decoupling zero modules, respectively, as submodules; and the cases of left and right invertible transfer functions are considered.

High scale impact in alignment and decoupling in two-Higgs-doublet models

NASA Astrophysics Data System (ADS)

Basler, Philipp; Ferreira, Pedro M.; Mühlleitner, Margarete; Santos, Rui

2018-05-01

The two-Higgs-doublet model (2HDM) provides an excellent benchmark to study physics beyond the Standard Model (SM). In this work, we discuss how the behavior of the model at high-energy scales causes it to have a scalar with properties very similar to those of the SM—which means the 2HDM can be seen to naturally favor a decoupling or alignment limit. For a type II 2HDM, we show that requiring the model to be theoretically valid up to a scale of 1 TeV, by studying the renormalization group equations (RGE) of the parameters of the model, causes a significant reduction in the allowed magnitude of the quartic couplings. This, combined with B -physics bounds, forces the model to be naturally decoupled. As a consequence, any nondecoupling limits in type II, like the wrong-sign scenario, are excluded. On the contrary, even with the very constraining limits for the Higgs couplings from the LHC, the type I model can deviate substantially from alignment. An RGE analysis similar to that made for type II shows, however, that requiring a single scalar to be heavier than about 500 GeV would be sufficient for the model to be decoupled. Finally, we show that the 2HDM is stable up to the Planck scale independently of which of the C P -even scalars is the discovered 125 GeV Higgs boson.

Fully decoupled monolithic projection method for natural convection problems

NASA Astrophysics Data System (ADS)

Pan, Xiaomin; Kim, Kyoungyoun; Lee, Changhoon; Choi, Jung-Il

2017-04-01

To solve time-dependent natural convection problems, we propose a fully decoupled monolithic projection method. The proposed method applies the Crank-Nicolson scheme in time and the second-order central finite difference in space. To obtain a non-iterative monolithic method from the fully discretized nonlinear system, we first adopt linearizations of the nonlinear convection terms and the general buoyancy term with incurring second-order errors in time. Approximate block lower-upper decompositions, along with an approximate factorization technique, are additionally employed to a global linearly coupled system, which leads to several decoupled subsystems, i.e., a fully decoupled monolithic procedure. We establish global error estimates to verify the second-order temporal accuracy of the proposed method for velocity, pressure, and temperature in terms of a discrete l2-norm. Moreover, according to the energy evolution, the proposed method is proved to be stable if the time step is less than or equal to a constant. In addition, we provide numerical simulations of two-dimensional Rayleigh-Bénard convection and periodic forced flow. The results demonstrate that the proposed method significantly mitigates the time step limitation, reduces the computational cost because only one Poisson equation is required to be solved, and preserves the second-order temporal accuracy for velocity, pressure, and temperature. Finally, the proposed method reasonably predicts a three-dimensional Rayleigh-Bénard convection for different Rayleigh numbers.

A conceptual and statistical framework for adaptive radiations with a key role for diversity dependence.

PubMed

Etienne, Rampal S; Haegeman, Bart

2012-10-01

In this article we propose a new framework for studying adaptive radiations in the context of diversity-dependent diversification. Diversity dependence causes diversification to decelerate at the end of an adaptive radiation but also plays a key role in the initial pulse of diversification. In particular, key innovations (which in our definition include novel traits as well as new environments) may cause decoupling of the diversity-dependent dynamics of the innovative clade from the diversity-dependent dynamics of its ancestral clade. We present a likelihood-based inference method to test for decoupling of diversity dependence using molecular phylogenies. The method, which can handle incomplete phylogenies, identifies when the decoupling took place and which diversification parameters are affected. We illustrate our approach by applying it to the molecular phylogeny of the North American clade of the legume tribe Psoraleeae (47 extant species, of which 4 are missing). Two diversification rate shifts were previously identified for this clade; our analysis shows that the first, positive shift can be associated with decoupling of two Pediomelum subgenera from the other Psoraleeae lineages, while we argue that the second, negative shift can be attributed to speciation being protracted. The latter explanation yields nonzero extinction rates, in contrast to previous findings. Our framework offers a new perspective on macroevolution: new environments and novel traits (ecological opportunity) and diversity dependence (ecological limits) cannot be considered separately.

Decoupling Identification for Serial Two-Link Two-Inertia System

NASA Astrophysics Data System (ADS)

Oaki, Junji; Adachi, Shuichi

The purpose of our study is to develop a precise model by applying the technique of system identification for the model-based control of a nonlinear robot arm, under taking joint-elasticity into consideration. We previously proposed a systematic identification method, called “decoupling identification,” for a “SCARA-type” planar two-link robot arm with elastic joints caused by the Harmonic-drive® reduction gears. The proposed method serves as an extension of the conventional rigid-joint-model-based identification. The robot arm is treated as a serial two-link two-inertia system with nonlinearity. The decoupling identification method using link-accelerometer signals enables the serial two-link two-inertia system to be divided into two linear one-link two-inertia systems. The MATLAB®'s commands for state-space model estimation are utilized in the proposed method. Physical parameters such as motor inertias, link inertias, joint-friction coefficients, and joint-spring coefficients are estimated through the identified one-link two-inertia systems using a gray-box approach. This paper describes accuracy evaluations using the two-link arm for the decoupling identification method under introducing closed-loop-controlled elements and varying amplitude-setup of identification-input. Experimental results show that the identification method also works with closed-loop-controlled elements. Therefore, the identification method is applicable to a “PUMA-type” vertical robot arm under gravity.

The role of stress waves in thoracic visceral injury from blast loading: modification of stress transmission by foams and high-density materials.

PubMed

Cooper, G J; Townend, D J; Cater, S R; Pearce, B P

1991-01-01

Materials have been applied to the thoracic wall of anaesthetised experimental animals exposed to blast overpressure to investigate the coupling of direct stress waves into the thorax and the relative contribution of compressive stress waves and gross thoracic compression to lung injury. The ultimate purpose of the work is to develop effective personal protection from the primary effects of blast overpressure--efficient protection can only be achieved if the injury mechanism is identified and characterized. Foam materials acted as acoustic couplers and resulted in a significant augmentation of the visceral injury; decoupling and elimination of injury were achieved by application of a high acoustic impedance layer on top of the foam. In vitro experiments studying stress wave transmission from air through various layers into an anechoic water chamber showed a significant increase in power transmitted by the foams, principally at high frequencies. Material such as copper or resin bonded Kevlar incorporated as a facing upon the foam achieved substantial decoupling at high frequencies--low frequency transmission was largely unaffected. An acoustic transmission model replicated the coupling of the blast waves into the anechoic water chamber. The studies suggest that direct transmission of stress waves plays a dominant role in lung parenchymal injury from blast loading and that gross thoracic compression is not the primary injury mechanism. Acoustic decoupling principles may therefore be employed to reduce the direct stress coupled into the body and thus reduce the severity of lung injury--the most simple decoupler is a high acoustic impedance material as a facing upon a foam, but decoupling layers may be optimized using acoustic transmission models. Conventional impacts producing high body wall velocities will also lead to stress wave generation and transmission--stress wave effects may dominate the visceral response to the impact with direct compression and shear contributing little to the aetiology of the injury.

Reaction monitoring using hyperpolarized NMR with scaling of heteronuclear couplings by optimal tracking.

PubMed

Zhang, Guannan; Schilling, Franz; Glaser, Steffen J; Hilty, Christian

2016-11-01

Off-resonance decoupling using the method of Scaling of Heteronuclear Couplings by Optimal Tracking (SHOT) enables determination of heteronuclear correlations of chemical shifts in single scan NMR spectra. Through modulation of J-coupling evolution by shaped radio frequency pulses, off resonance decoupling using SHOT pulses causes a user-defined dependence of the observed J-splitting, such as the splitting of 13 C peaks, on the chemical shift offset of coupled nuclei, such as 1 H. Because a decoupling experiment requires only a single scan, this method is suitable for characterizing on-going chemical reactions using hyperpolarization by dissolution dynamic nuclear polarization (D-DNP). We demonstrate the calculation of [ 13 C, 1 H] chemical shift correlations of the carbanionic active sites from hyperpolarized styrene polymerized using sodium naphthalene as an initiator. While off resonance decoupling by SHOT pulses does not enhance the resolution in the same way as a 2D NMR spectrum would, the ability to obtain the correlations in single scans makes this method ideal for determination of chemical shifts in on-going reactions on the second time scale. In addition, we present a novel SHOT pulse that allows to scale J-splittings 50% larger than the respective J-coupling constant. This feature can be used to enhance the resolution of the indirectly detected chemical shift and reduce peak overlap, as demonstrated in a model reaction between p-anisaldehyde and isobutylamine. For both pulses, the accuracy is evaluated under changing signal-to-noise ratios (SNR) of the peaks from reactants and reaction products, with an overall standard deviation of chemical shift differences compared to reference spectra of 0.02ppm when measured on a 400MHz NMR spectrometer. Notably, the appearance of decoupling side-bands, which scale with peak intensity, appears to be of secondary importance. Copyright © 2016 Elsevier Inc. All rights reserved.

The Linear Parameters and the Decoupling Matrix for Linearly Coupled Motion in 6 Dimensional Phase Space

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

Parzen, George

It will be shown that starting from a coordinate system where the 6 phase space coordinates are linearly coupled, one can go to a new coordinate system, where the motion is uncoupled, by means of a linear transformation. The original coupled coordinates and the new uncoupled coordinates are related by a 6 x 6 matrix, R. R will be called the decoupling matrix. It will be shown that of the 36 elements of the 6 x 6 decoupling matrix R, only 12 elements are independent. This may be contrasted with the results for motion in 4- dimensional phase space, wheremore » R has 4 independent elements. A set of equations is given from which the 12 elements of R can be computed from the one period transfer matrix. This set of equations also allows the linear parameters, the β i,α i, i = 1, 3, for the uncoupled coordinates, to be computed from the one period transfer matrix. An alternative procedure for computing the linear parameters,β i,α i, i = 1, 3, and the 12 independent elements of the decoupling matrix R is also given which depends on computing the eigenvectors of the one period transfer matrix. These results can be used in a tracking program, where the one period transfer matrix can be computed by multiplying the transfer matrices of all the elements in a period, to compute the linear parameters α i and β i, i = 1, 3, and the elements of the decoupling matrix R. The procedure presented here for studying coupled motion in 6-dimensional phase space can also be applied to coupled motion in 4-dimensional phase space, where it may be a useful alternative procedure to the procedure presented by Edwards and Teng. In particular, it gives a simpler programing procedure for computing the beta functions and the emittances for coupled motion in 4-dimensional phase space.« less

The linear parameters and the decoupling matrix for linearly coupled motion in 6 dimensional phase space. Informal report

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

Parzen, G.

It will be shown that starting from a coordinate system where the 6 phase space coordinates are linearly coupled, one can go to a new coordinate system, where the motion is uncoupled, by means of a linear transformation. The original coupled coordinates and the new uncoupled coordinates are related by a 6 {times} 6 matrix, R. R will be called the decoupling matrix. It will be shown that of the 36 elements of the 6 {times} 6 decoupling matrix R, only 12 elements are independent. This may be contrasted with the results for motion in 4-dimensional phase space, where Rmore » has 4 independent elements. A set of equations is given from which the 12 elements of R can be computed from the one period transfer matrix. This set of equations also allows the linear parameters, {beta}{sub i}, {alpha}{sub i} = 1, 3, for the uncoupled coordinates, to be computed from the one period transfer matrix. An alternative procedure for computing the linear parameters, the {beta}{sub i}, {alpha}{sub i} i = 1, 3, and the 12 independent elements of the decoupling matrix R is also given which depends on computing the eigenvectors of the one period transfer matrix. These results can be used in a tracking program, where the one period transfer matrix can be computed by multiplying the transfer matrices of all the elements in a period, to compute the linear parameters {alpha}{sub i} and {beta}{sub i}, i = 1, 3, and the elements of the decoupling matrix R. The procedure presented here for studying coupled motion in 6-dimensional phase space can also be applied to coupled motion in 4-dimensional phase space, where it may be a useful alternative procedure to the procedure presented by Edwards and Teng. In particular, it gives a simpler programming procedure for computing the beta functions and the emittances for coupled motion in 4-dimensional phase space.« less

Local Hamiltonian Monte Carlo study of the massive schwinger model, the decoupling of heavy flavours

NASA Astrophysics Data System (ADS)

Ranft, J.

1983-12-01

The massive Schwinger model with two flavours is studied using the local hamiltonian lattice Monte Carlo method. Chiral symmetry breaking is studied using the fermion condensate as order parameter. For a small ratio of the two fermion masses, degeneracy of the two flavours is found. For a large ratio of the masses, the heavy flavour decouples and the light fermion behaves like in the one flavour Schwinger model. On leave from Sektion Physik, Karl-Marx-Universität, Leipzig, GDR.

Method and apparatus for decoupled thermo-catalytic pollution control

DOEpatents

Tabatabaie-Raissi, Ali; Muradov, Nazim Z.; Martin, Eric

2006-07-11

A new method for design and scale-up of thermocatalytic processes is disclosed. The method is based on optimizing process energetics by decoupling of the process energetics from the DRE for target contaminants. The technique is applicable to high temperature thermocatalytic reactor design and scale-up. The method is based on the implementation of polymeric and other low-pressure drop support for thermocatalytic media as well as the multifunctional catalytic media in conjunction with a novel rotating fluidized particle bed reactor.

Origin of gauge invariance in string theory

NASA Technical Reports Server (NTRS)

Horowitz, G. T.; Strominger, A.

1986-01-01

A first quantization of the space-time embedding Chi exp mu and the world-sheet metric rho of the open bosonic string. The world-sheet metric rho decouples from S-matrix elements in 26 dimensions. This formulation of the theory naturally includes 26-dimensional gauge transformations. The gauge invariance of S-matrix elements is a direct consequence of the decoupling of rho. Second quantization leads to a string field Phi(Chi exp mu, rho) with a gauge-covariant equation of motion.

Implementation of a decoupled controller for a magnetic suspension system using electromagnets mounted in a planar array

NASA Technical Reports Server (NTRS)

Cox, D. E.; Groom, N. J.

1994-01-01

An implementation of a decoupled, single-input/single-output control approach for a large angle magnetic suspension test fixture is described. Numerical and experimental results are presented. The experimental system is a laboratory model large gap magnetic suspension system which provides five degree-of-freedom control of a cylindrical suspended element. The suspended element contains a core composed of permanent magnet material and is levitated above five electromagnets mounted in a planar array.

Precision Quantum Control and Error-Suppressing Quantum Firmware for Robust Quantum Computing

DTIC Science & Technology

2014-09-24

Biercuk, Lorenza Viola. Long-time Low - latency Quantum Memory by Dynamical Decoupling, arXiv:1206.6087v1 (06 2012) L. Viola, G. A. Paz-Silva . A...International Patent Application (PCT/AU2013/000649) D. Hayes, K. Khodjasteh L. Viola, M.J. Biercuk, “Long-time low - latency quantum memory by dynamical...Khodjasteh L. Viola, M.J. Biercuk, University of Sydney A28 Physics Road Sydney NS 2006 Long-time low - latency quantum membory by dynamical decoupling

Anisotropic solutions by gravitational decoupling

NASA Astrophysics Data System (ADS)

Ovalle, J.; Casadio, R.; da Rocha, R.; Sotomayor, A.

2018-02-01

We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the surface of the star with the outer Schwarzschild space-time are studied in great detail, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent.

A multilevel control approach for a modular structured space platform

NASA Technical Reports Server (NTRS)

Chichester, F. D.; Borelli, M. T.

1981-01-01

A three axis mathematical representation of a modular assembled space platform consisting of interconnected discrete masses, including a deployable truss module, was derived for digital computer simulation. The platform attitude control system as developed to provide multilevel control utilizing the Gauss-Seidel second level formulation along with an extended form of linear quadratic regulator techniques. The objectives of the multilevel control are to decouple the space platform's spatial axes and to accommodate the modification of the platform's configuration for each of the decoupled axes.

Flight experience with manually controlled unconventional aircraft motions

NASA Technical Reports Server (NTRS)

Barfield, A. F.

1978-01-01

A modified YF-16 aircraft was used to flight demonstrate decoupled modes under the USAF Fighter Control Configured Vehicle (CCV) Program. The direct force capabilities were used to implement seven manually controlled unconventional modes on the aircraft, allowing flat turns, decoupled normal acceleration control, independent longitudinal and lateral translations, uncoupled elevation and azimuth aiming, and blended direct lift. This paper describes the design, development, and flight testing of these control modes. The need for task-tailored mode authorities, gain-scheduling and selected closed-loop design is discussed.

Decoupling the Stationary Navier-Stokes-Darcy System with the Beavers-Joseph-Saffman Interface Condition

DOE PAGES

Cao, Yong; Chu, Yuchuan; He, Xiaoming; ...

2013-01-01

This paper proposes a domain decomposition method for the coupled stationary Navier-Stokes and Darcy equations with the Beavers-Joseph-Saffman interface condition in order to improve the efficiency of the finite element method. The physical interface conditions are directly utilized to construct the boundary conditions on the interface and then decouple the Navier-Stokes and Darcy equations. Newton iteration will be used to deal with the nonlinear systems. Numerical results are presented to illustrate the features of the proposed method.

A Note on the Disturbance Decoupling Problem for Retarded Systems.

DTIC Science & Technology

1984-10-01

disturbance decoupling problem f or linear control system is to design a feedback control law in such a way that the disturbances do not * influence...and in 141 by Pandolfi who analyses the situation in some detail. HeU concludes that for retarded systems one needs an unbounded feedback control law...ult) 6 JP is the control input, d(t) 6 AR is same disturbance, and z(t) e 3k is the output to be regularted. We assume that L is a bounded linear

Decoupling Hydrogen and Oxygen Production in Acidic Water Electrolysis Using a Polytriphenylamine-Based Battery Electrode.

PubMed

Ma, Yuanyuan; Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

2018-03-05

Hydrogen production through water splitting is considered a promising approach for solar energy harvesting. However, the variable and intermittent nature of solar energy and the co-production of H 2 and O 2 significantly reduce the flexibility of this approach, increasing the costs of its use in practical applications. Herein, using the reversible n-type doping/de-doping reaction of the solid-state polytriphenylamine-based battery electrode, we decouple the H 2 and O 2 production in acid water electrolysis. In this architecture, the H 2 and O 2 production occur at different times, which eliminates the issue of gas mixing and adapts to the variable and intermittent nature of solar energy, facilitating the conversion of solar energy to hydrogen (STH). Furthermore, for the first time, we demonstrate a membrane-free solar water splitting through commercial photovoltaics and the decoupled acid water electrolysis, which potentially paves the way for a new approach for solar water splitting. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leaf economics and hydraulic traits are decoupled in five species-rich tropical-subtropical forests.

PubMed

Li, Le; McCormack, M Luke; Ma, Chengen; Kong, Deliang; Zhang, Qian; Chen, Xiaoyong; Zeng, Hui; Niinemets, Ülo; Guo, Dali

2015-09-01

Leaf economics and hydraulic traits are critical to leaf photosynthesis, yet it is debated whether these two sets of traits vary in a fully coordinated manner or there is room for independent variation. Here, we tested the relationship between leaf economics traits, including leaf nitrogen concentration and leaf dry mass per area, and leaf hydraulic traits including stomatal density and vein density in five tropical-subtropical forests. Surprisingly, these two suites of traits were statistically decoupled. This decoupling suggests that independent trait dimensions exist within a leaf, with leaf economics dimension corresponding to light capture and tissue longevity, and the hydraulic dimension to water-use and leaf temperature maintenance. Clearly, leaf economics and hydraulic traits can vary independently, thus allowing for more possible plant trait combinations. Compared with a single trait dimension, multiple trait dimensions may better enable species adaptations to multifarious niche dimensions, promote diverse plant strategies and facilitate species coexistence. © 2015 John Wiley & Sons Ltd/CNRS.

Symmetry operators and decoupled equations for linear fields on black hole spacetimes

NASA Astrophysics Data System (ADS)

Araneda, Bernardo

2017-02-01

In the class of vacuum Petrov type D spacetimes with cosmological constant, which includes the Kerr-(A)dS black hole as a particular case, we find a set of four-dimensional operators that, when composed off shell with the Dirac, Maxwell and linearized gravity equations, give a system of equations for spin weighted scalars associated with the linear fields, that decouple on shell. Using these operator relations we give compact reconstruction formulae for solutions of the original spinor and tensor field equations in terms of solutions of the decoupled scalar equations. We also analyze the role of Killing spinors and Killing-Yano tensors in the spin weight zero equations and, in the case of spherical symmetry, we compare our four-dimensional formulation with the standard 2  +  2 decomposition and particularize to the Schwarzschild-(A)dS black hole. Our results uncover a pattern that generalizes a number of previous results on Teukolsky-like equations and Debye potentials for higher spin fields.

Accuracy of dynamical-decoupling-based spectroscopy of Gaussian noise

NASA Astrophysics Data System (ADS)

Szańkowski, Piotr; Cywiński, Łukasz

2018-03-01

The fundamental assumption of dynamical-decoupling-based noise spectroscopy is that the coherence decay rate of qubit (or qubits) driven with a sequence of many pulses, is well approximated by the environmental noise spectrum spanned on frequency comb defined by the sequence. Here we investigate the precise conditions under which this commonly used spectroscopic approach is quantitatively correct. To this end we focus on two representative examples of spectral densities: the long-tailed Lorentzian, and finite-ranged Gaussian—both expected to be encountered when using the qubit for nanoscale nuclear resonance imaging. We have found that, in contrast to Lorentz spectrum, for which the corrections to the standard spectroscopic formulas can easily be made negligible, the spectra with finite range are more challenging to reconstruct accurately. For Gaussian line shape of environmental spectral density, direct application of the standard dynamical-decoupling-based spectroscopy leads to erroneous attribution of long-tail behavior to the reconstructed spectrum. Fortunately, artifacts such as this, can be completely avoided with the simple extension to standard reconstruction method.

Decoupling optical function and geometrical form using conformal flexible dielectric metasurfaces

DOE PAGES

Kamali, Seyedeh Mahsa; Arbabi, Amir; Arbabi, Ehsan; ...

2016-05-19

Physical geometry and optical properties of objects are correlated: cylinders focus light to a line, spheres to a point and arbitrarily shaped objects introduce optical aberrations. Multifunctional components with decoupled geometrical form and optical function are needed when specific optical functionalities must be provided while the shapes are dictated by other considerations like ergonomics, aerodynamics or aesthetics. Here we demonstrate an approach for decoupling optical properties of objects from their physical shape using thin and flexible dielectric metasurfaces which conform to objects' surface and change their optical properties. The conformal metasurfaces are composed of silicon nano-posts embedded in a polymermore » substrate that locally modify near-infrared (λ = 915 nm) optical wavefronts. As proof of concept, we show that cylindrical lenses covered with metasurfaces can be transformed to function as aspherical lenses focusing light to a point. Lastly, the conformal metasurface concept is highly versatile for developing arbitrarily shaped multi-functional optical devices.« less

Decoupling kinematics and mechanics reveals coding properties of trigeminal ganglion neurons in the rat vibrissal system

PubMed Central

Bush, Nicholas E; Schroeder, Christopher L; Hobbs, Jennifer A; Yang, Anne ET; Huet, Lucie A; Solla, Sara A; Hartmann, Mitra JZ

2016-01-01

Tactile information available to the rat vibrissal system begins as external forces that cause whisker deformations, which in turn excite mechanoreceptors in the follicle. Despite the fundamental mechanical origin of tactile information, primary sensory neurons in the trigeminal ganglion (Vg) have often been described as encoding the kinematics (geometry) of object contact. Here we aimed to determine the extent to which Vg neurons encode the kinematics vs. mechanics of contact. We used models of whisker bending to quantify mechanical signals (forces and moments) at the whisker base while simultaneously monitoring whisker kinematics and recording single Vg units in both anesthetized rats and awake, body restrained rats. We employed a novel manual stimulation technique to deflect whiskers in a way that decouples kinematics from mechanics, and used Generalized Linear Models (GLMs) to show that Vg neurons more directly encode mechanical signals when the whisker is deflected in this decoupled stimulus space. DOI: http://dx.doi.org/10.7554/eLife.13969.001 PMID:27348221

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

Zhang, Zhiqiang; Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706; Geng, Dalong

A simple and effective decoupled finite element analysis method was developed for simulating both the piezoelectric and flexoelectric effects of zinc oxide (ZnO) and barium titanate (BTO) nanowires (NWs). The piezoelectric potential distribution on a ZnO NW was calculated under three deformation conditions (cantilever, three-point, and four-point bending) and compared to the conventional fully coupled method. The discrepancies of the electric potential maximums from these two methods were found very small, validating the accuracy and effectiveness of the decoupled method. Both ZnO and BTO NWs yielded very similar potential distributions. Comparing the potential distributions induced by the piezoelectric and flexoelectricmore » effects, we identified that the middle segment of a four-point bending NW beam is the ideal place for measuring the flexoelectric coefficient, because the uniform parallel plate capacitor-like potential distribution in this region is exclusively induced by the flexoelectric effect. This decoupled method could provide a valuable guideline for experimental measurements of the piezoelectric effects and flexoelectric effects in the nanometer scale.« less

A structurally decoupled mechanism for measuring wrist torque in three degrees of freedom

NASA Astrophysics Data System (ADS)

Pan, Lizhi; Yang, Zhen; Zhang, Dingguo

2015-10-01

The wrist joint is a critical part of the human body for movement. Measuring the torque of the wrist with three degrees of freedom (DOFs) is important in some fields, including rehabilitation, biomechanics, ergonomics, and human-machine interfacing. However, the particular structure of the wrist joint makes it difficult to measure the torque in all three directions simultaneously. This work develops a structurally decoupled instrument for measuring and improving the measurement accuracy of 3-DOF wrist torque during isometric contraction. Three single-axis torque sensors were embedded in a customized mechanical structure. The dimensions and components of the instrument were designed based on requirement of manufacturability. A prototype of the instrument was machined, assembled, integrated, and tested. The results show that the structurally decoupled mechanism is feasible for acquiring wrist torque data in three directions either independently or simultaneously. As a case study, we use the device to measure wrist torques concurrently with electromyography signal acquisition in preparation for simultaneous and proportional myoelectric control of prostheses.

Decoupled Method for Reconstruction of Surface Conditions From Internal Temperatures On Ablative Materials With Uncertain Recession Model

NASA Technical Reports Server (NTRS)

Oliver, A. Brandon

2017-01-01

Obtaining measurements of flight environments on ablative heat shields is both critical for spacecraft development and extremely challenging due to the harsh heating environment and surface recession. Thermocouples installed several millimeters below the surface are commonly used to measure the heat shield temperature response, but an ill-posed inverse heat conduction problem must be solved to reconstruct the surface heating environment from these measurements. Ablation can contribute substantially to the measurement response making solutions to the inverse problem strongly dependent on the recession model, which is often poorly characterized. To enable efficient surface reconstruction for recession model sensitivity analysis, a method for decoupling the surface recession evaluation from the inverse heat conduction problem is presented. The decoupled method is shown to provide reconstructions of equivalent accuracy to the traditional coupled method but with substantially reduced computational effort. These methods are applied to reconstruct the environments on the Mars Science Laboratory heat shield using diffusion limit and kinetically limited recession models.

Rotorcraft flight control design using quantitative feedback theory and dynamic crossfeeds

NASA Technical Reports Server (NTRS)

Cheng, Rendy P.

1995-01-01

A multi-input, multi-output controls design with robust crossfeeds is presented for a rotorcraft in near-hovering flight using quantitative feedback theory (QFT). Decoupling criteria are developed for dynamic crossfeed design and implementation. Frequency dependent performance metrics focusing on piloted flight are developed and tested on 23 flight configurations. The metrics show that the resulting design is superior to alternative control system designs using conventional fixed-gain crossfeeds and to feedback-only designs which rely on high gains to suppress undesired off-axis responses. The use of dynamic, robust crossfeeds prior to the QFT design reduces the magnitude of required feedback gain and results in performance that meets current handling qualities specifications relative to the decoupling of off-axis responses. The combined effect of the QFT feedback design following the implementation of low-order, dynamic crossfeed compensator successfully decouples ten of twelve off-axis channels. For the other two channels it was not possible to find a single, low-order crossfeed that was effective.

Reusable Launch Vehicle Control in Multiple Time Scale Sliding Modes

NASA Technical Reports Server (NTRS)

Shtessel, Yuri

1999-01-01

A reusable launch vehicle control problem during ascent is addressed via multiple-time scaled continuous sliding mode control. The proposed sliding mode controller utilizes a two-loop structure and provides robust, de-coupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of bounded external disturbances and plant uncertainties. Sliding mode control causes the angular rate and orientation angle tracking error dynamics to be constrained to linear, de-coupled, homogeneous, and vector valued differential equations with desired eigenvalues placement. The dual-time scale sliding mode controller was designed for the X-33 technology demonstration sub-orbital launch vehicle in the launch mode. 6DOF simulation results show that the designed controller provides robust, accurate, de-coupled tracking of the orientation angle command profiles in presence of external disturbances and vehicle inertia uncertainties. It creates possibility to operate the X-33 vehicle in an aircraft-like mode with reduced pre-launch adjustment of the control system.

A structurally decoupled mechanism for measuring wrist torque in three degrees of freedom.

PubMed

Pan, Lizhi; Yang, Zhen; Zhang, Dingguo

2015-10-01

The wrist joint is a critical part of the human body for movement. Measuring the torque of the wrist with three degrees of freedom (DOFs) is important in some fields, including rehabilitation, biomechanics, ergonomics, and human-machine interfacing. However, the particular structure of the wrist joint makes it difficult to measure the torque in all three directions simultaneously. This work develops a structurally decoupled instrument for measuring and improving the measurement accuracy of 3-DOF wrist torque during isometric contraction. Three single-axis torque sensors were embedded in a customized mechanical structure. The dimensions and components of the instrument were designed based on requirement of manufacturability. A prototype of the instrument was machined, assembled, integrated, and tested. The results show that the structurally decoupled mechanism is feasible for acquiring wrist torque data in three directions either independently or simultaneously. As a case study, we use the device to measure wrist torques concurrently with electromyography signal acquisition in preparation for simultaneous and proportional myoelectric control of prostheses.

Visualizing decoupling in nanocrystalline alloys: A FORC-temperature analysis

NASA Astrophysics Data System (ADS)

Rivas, M.; Martínez-García, J. C.; Gorria, P.

2016-02-01

Devitrifying ferromagnetic amorphous precursors in the adequate conditions may give rise to disordered assemblies of densely packed nanocrystals with extraordinary magnetic softness well explained by the exchange coupling among multiple crystallites. Whether the magnetic exchange interaction is produced by direct contact or mediated by the intergranular amorphous matrix has a strong influence on the behaviour of the system above room temperature. Multi-phase amorphous-nanocrystalline systems dramatically harden when approaching the amorphous Curie temperature (TC) due to the hard grains decoupling. The study of the thermally induced decoupling of nanosized crystallites embedded in an amorphous matrix has been performed in this work by the first-order reversal curves (FORCs) analysis. We selected a Fe-rich amorphous alloy with TC = 330 K, in order to follow the evolution of the FORC diagrams obtained below and above such temperature in samples with different percentages of nanocrystalline phase. The existence of up to four regions exhibiting unlike magnetic behaviours is unambiguously determined from the temperature evolution of the FORC.

Decoupled tracking and thermal monitoring of non-stationary targets.

PubMed

Tan, Kok Kiong; Zhang, Yi; Huang, Sunan; Wong, Yoke San; Lee, Tong Heng

2009-10-01

Fault diagnosis and predictive maintenance address pertinent economic issues relating to production systems as an efficient technique can continuously monitor key health parameters and trigger alerts when critical changes in these variables are detected, before they lead to system failures and production shutdowns. In this paper, we present a decoupled tracking and thermal monitoring system which can be used on non-stationary targets of closed systems such as machine tools. There are three main contributions from the paper. First, a vision component is developed to track moving targets under a monitor. Image processing techniques are used to resolve the target location to be tracked. Thus, the system is decoupled and applicable to closed systems without the need for a physical integration. Second, an infrared temperature sensor with a built-in laser for locating the measurement spot is deployed for non-contact temperature measurement of the moving target. Third, a predictive motion control system holds the thermal sensor and follows the moving target efficiently to enable continuous temperature measurement and monitoring.

Water Splitting via Decoupled Photocatalytic Water Oxidation and Electrochemical Proton Reduction Mediated by Electron-Coupled-Proton Buffer.

PubMed

Li, Fei; Yu, Fengshou; Du, Jian; Wang, Yong; Zhu, Yong; Li, Xiaona; Sun, Licheng

2017-10-18

Water splitting mediated by electron-coupled-proton buffer (ECPB) provides an efficient way to avoid gas mixing by separating oxygen evolution from hydrogen evolution in space and time. Though electrochemical and photoelectrochemcial water oxidation have been incorporated in such a two-step water splitting system, alternative ways to reduce the cost and energy input for decoupling two half-reactions are desired. Herein, we show the feasibility of photocatalytic oxygen evolution in a powder system with BiVO 4 as a photocatalyst and polyoxometalate H 3 PMo 12 O 40 as an electron and proton acceptor. The resulting reaction mixture was allowed to be directly used for the subsequent hydrogen evolution with the reduced H 3 PMo 12 O 40 as electron and proton donors. Our system exhibits excellent stability in repeated oxygen and hydrogen evolution, which brings considerable convenience to decoupled water splitting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitivity enhancement in whole-body natural abundance 13C spectroscopy using 13C/1H double-resonance techniques at 4 tesla.

PubMed

Bomsdorf, H; Röschmann, P; Wieland, J

1991-11-01

In vivo 13C spectroscopy experiments were performed using a whole-body MR system at a static field of 4 T. The main goal of the investigations was to evaluate the sensitivity increase achievable by means of 13C/1H double-resonance techniques at 4 T. Spectra from subcutaneous fat as well as muscle glycogen from the lower leg were acquired using frequency selective proton decoupling and the polarization transfer method SINEPT. With respect to measurements on subcutaneous fat, polarization transfer turned out to be more efficient than selective decoupling. About a fourfold enhancement in spectral peak intensity for the C = C line doublet of the unsaturated fatty acid chain was obtained. Combining polarization transfer with decoupling yielded a factor of 6 in signal amplitude. In contrast to that, the signal enhancement observed in measurements on the glycogen C-1 resonance was only around twofold. The lower efficiency is explained by fast T2 relaxation of the proton transition. A T2 value of about 3 ms was derived from the experimental data. Acquisition times as low as 3 min were realized for normal level glycogen in human calf muscle, enabling a time resolution adequate for dynamic studies on muscle glycogen depletion. Aspects of RF power absorption in tissue and the generally higher efficiency make polarization transfer methods preferable to selective decoupling in whole-body 13C spectroscopy at 4 T.

Exact decoupling of the Dirac Hamiltonian. II. The generalized Douglas-Kroll-Hess transformation up to arbitrary order.

PubMed

Reiher, Markus; Wolf, Alexander

2004-12-08

In order to achieve exact decoupling of the Dirac Hamiltonian within a unitary transformation scheme, we have discussed in part I of this series that either a purely numerical iterative technique (the Barysz-Sadlej-Snijders method) or a stepwise analytic approach (the Douglas-Kroll-Hess method) are possible. For the evaluation of Douglas-Kroll-Hess Hamiltonians up to a pre-defined order it was shown that a symbolic scheme has to be employed. In this work, an algorithm for this analytic derivation of Douglas-Kroll-Hess Hamiltonians up to any arbitrary order in the external potential is presented. We discuss how an estimate for the necessary order for exact decoupling (within machine precision) for a given system can be determined from the convergence behavior of the Douglas-Kroll-Hess expansion prior to a quantum chemical calculation. Once this maximum order has been accomplished, the spectrum of the positive-energy part of the decoupled Hamiltonian, e.g., for electronic bound states, cannot be distinguished from the corresponding part of the spectrum of the Dirac operator. An efficient scalar-relativistic implementation of the symbolic operations for the evaluation of the positive-energy part of the block-diagonal Hamiltonian is presented, and its accuracy is tested for ground-state energies of one-electron ions over the whole periodic table. Furthermore, the first many-electron calculations employing sixth up to fourteenth order DKH Hamiltonians are presented. (c) 2004 American Institute of Physics.

Study of the Algorithm of Backtracking Decoupling and Adaptive Extended Kalman Filter Based on the Quaternion Expanded to the State Variable for Underwater Glider Navigation

PubMed Central

Huang, Haoqian; Chen, Xiyuan; Zhou, Zhikai; Xu, Yuan; Lv, Caiping

2014-01-01

High accuracy attitude and position determination is very important for underwater gliders. The cross-coupling among three attitude angles (heading angle, pitch angle and roll angle) becomes more serious when pitch or roll motion occurs. This cross-coupling makes attitude angles inaccurate or even erroneous. Therefore, the high accuracy attitude and position determination becomes a difficult problem for a practical underwater glider. To solve this problem, this paper proposes backing decoupling and adaptive extended Kalman filter (EKF) based on the quaternion expanded to the state variable (BD-AEKF). The backtracking decoupling can eliminate effectively the cross-coupling among the three attitudes when pitch or roll motion occurs. After decoupling, the adaptive extended Kalman filter (AEKF) based on quaternion expanded to the state variable further smoothes the filtering output to improve the accuracy and stability of attitude and position determination. In order to evaluate the performance of the proposed BD-AEKF method, the pitch and roll motion are simulated and the proposed method performance is analyzed and compared with the traditional method. Simulation results demonstrate the proposed BD-AEKF performs better. Furthermore, for further verification, a new underwater navigation system is designed, and the three-axis non-magnetic turn table experiments and the vehicle experiments are done. The results show that the proposed BD-AEKF is effective in eliminating cross-coupling and reducing the errors compared with the conventional method. PMID:25479331

Study of the algorithm of backtracking decoupling and adaptive extended Kalman filter based on the quaternion expanded to the state variable for underwater glider navigation.

PubMed

Huang, Haoqian; Chen, Xiyuan; Zhou, Zhikai; Xu, Yuan; Lv, Caiping

2014-12-03

High accuracy attitude and position determination is very important for underwater gliders. The cross-coupling among three attitude angles (heading angle, pitch angle and roll angle) becomes more serious when pitch or roll motion occurs. This cross-coupling makes attitude angles inaccurate or even erroneous. Therefore, the high accuracy attitude and position determination becomes a difficult problem for a practical underwater glider. To solve this problem, this paper proposes backing decoupling and adaptive extended Kalman filter (EKF) based on the quaternion expanded to the state variable (BD-AEKF). The backtracking decoupling can eliminate effectively the cross-coupling among the three attitudes when pitch or roll motion occurs. After decoupling, the adaptive extended Kalman filter (AEKF) based on quaternion expanded to the state variable further smoothes the filtering output to improve the accuracy and stability of attitude and position determination. In order to evaluate the performance of the proposed BD-AEKF method, the pitch and roll motion are simulated and the proposed method performance is analyzed and compared with the traditional method. Simulation results demonstrate the proposed BD-AEKF performs better. Furthermore, for further verification, a new underwater navigation system is designed, and the three-axis non-magnetic turn table experiments and the vehicle experiments are done. The results show that the proposed BD-AEKF is effective in eliminating cross-coupling and reducing the errors compared with the conventional method.

Integration of serpentine channels for microchip electrophoresis with a palladium decoupler and electrochemical detection

PubMed Central

Bowen, Amanda L; Martin, R. Scott

2010-01-01

While it has been shown that microchip electrophoresis with electrochemical detection can be used to separate and detect electroactive species, there is a need to increase the separation performance of these devices so that complex mixtures can be routinely analyzed. Previous work in microchip electrophoresis has demonstrated that increasing the separation channel length leads to an increase in resolution between closely eluting analytes. This paper details the use of lengthened serpentine microchannels for microchip electrophoresis and electrochemical detection where a palladium decoupler is used to ground the separation voltage so that the working electrodes remain in the fluidic network. In this work, palladium electrodepositions were used to increase the decoupler surface area and more efficiently dissipate hydrogen produced at the decoupler. Dopamine and norepinephrine, which only differ in structure by a hydroxyl group, were used as model analytes. It was found that increasing the separation channel length led to improvements in both resolution and the number of theoretical plates for these analytes. The use of a bi-layer valving device, where PDMS-based valves are utilized for the injection process, along with serpentine microchannels and amperometric detection resulted in a multi-analyte separation and an average of 28,700 theoretical plates. It was also shown that the increased channel length is beneficial when separating and detecting analytes from a high ionic strength matrix. This was demonstrated by monitoring the stimulated release of neuro-transmitters from a confluent layer of PC 12 cells. PMID:19739137

Exact decoupling of the Dirac Hamiltonian. II. The generalized Douglas-Kroll-Hess transformation up to arbitrary order

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

Reiher, Markus; Wolf, Alexander

In order to achieve exact decoupling of the Dirac Hamiltonian within a unitary transformation scheme, we have discussed in part I of this series that either a purely numerical iterative technique (the Barysz-Sadlej-Snijders method) or a stepwise analytic approach (the Douglas-Kroll-Hess method) are possible. For the evaluation of Douglas-Kroll-Hess Hamiltonians up to a pre-defined order it was shown that a symbolic scheme has to be employed. In this work, an algorithm for this analytic derivation of Douglas-Kroll-Hess Hamiltonians up to any arbitrary order in the external potential is presented. We discuss how an estimate for the necessary order for exactmore » decoupling (within machine precision) for a given system can be determined from the convergence behavior of the Douglas-Kroll-Hess expansion prior to a quantum chemical calculation. Once this maximum order has been accomplished, the spectrum of the positive-energy part of the decoupled Hamiltonian, e.g., for electronic bound states, cannot be distinguished from the corresponding part of the spectrum of the Dirac operator. An efficient scalar-relativistic implementation of the symbolic operations for the evaluation of the positive-energy part of the block-diagonal Hamiltonian is presented, and its accuracy is tested for ground-state energies of one-electron ions over the whole periodic table. Furthermore, the first many-electron calculations employing sixth up to fourteenth order DKH Hamiltonians are presented.« less

The impact of perceived similarity on tacit coordination: propensity for matching and aversion to decoupling choices

PubMed Central

Chierchia, Gabriele; Coricelli, Giorgio

2015-01-01

Homophily, or “love for similar others,” has been shown to play a fundamental role in the formation of interpersonal ties and social networks. Yet no study has investigated whether perceived similarities can affect tacit coordination. We had 68 participants attempt to maximize real monetary earnings by choosing between a safe but low paying option (that could be obtained with certainty) and a potentially higher paying but “risky” one, which depended on the choice of a matched counterpart. While making their choices participants were mutually informed of whether their counterparts similarly or dissimilarly identified with three person-descriptive words as themselves. We found that similarity increased the rate of “risky” choices only when the game required counterparts to match their choices (stag hunt games). Conversely, similarity led to decreased risk rates when they were to tacitly decouple their choices (entry games). Notably, though similarity increased coordination in the matching environment, it did not did not increase it in the decoupling game. In spite of this, similarity increased (expected) payoffs across both coordination environments. This could shed light on why homophily is so successful as a social attractor. Finally, this propensity for matching and aversion to decoupling choices was not observed when participants “liked” their counterparts but were dissimilar to them. We thus conclude that the impact of similarity of coordination should not be reduced to “liking” others (i.e., social preferences) but it is also about predicting them. PMID:26283940

Urban Economies Resource Productivity and Decoupling: Metabolism Trends of 1996-2011 in Sweden, Stockholm, and Gothenburg.

PubMed

Kalmykova, Yuliya; Rosado, Leonardo; Patrício, João

2015-07-21

Resource productivity and evidence of economic decoupling were investigated on the basis of the time series in 1996-2011 of material flow analysis for Sweden, Stockholm, and Gothenburg. In the three cases, absolute reductions in CO2 emissions by about 20% were observed, energy consumption per capita decreased, while gross domestic product (GDP) per capita grew. The energy consumption of the residential and public sectors decreased drastically, while the transport energy consumption is still growing steadily. Decoupling of the economy as a whole (i.e., including materials) is not yet happening at any scale. The domestic material consumption (DMC) continues to increase, in parallel with the GDP. The rate of increase for DMC is slower than that for GDP in both Stockholm and Sweden as a whole (i.e., relative decoupling). The metabolism of the cities does not replicate the national metabolism, and the two cities each have their own distinct metabolism profiles. As a consequence, policy implications for each of the case studies were suggested. In general, because of the necessarily different roles of the two cities in the national economy, generic resource productivity benchmarks, such as CO2 per capita, should be avoided in favor of sectorial benchmarks, such as industry, transport, or residential CO2 per capita. In addition, the share of the city impacts caused by the provision of a service for the rest of the country, such as a port, could be allocated to the national economy.

Real-space decoupling transformation for quantum many-body systems.

PubMed

Evenbly, G; Vidal, G

2014-06-06

We propose a real-space renormalization group method to explicitly decouple into independent components a many-body system that, as in the phenomenon of spin-charge separation, exhibits separation of degrees of freedom at low energies. Our approach produces a branching holographic description of such systems that opens the path to the efficient simulation of the most entangled phases of quantum matter, such as those whose ground state violates a boundary law for entanglement entropy. As in the coarse-graining transformation of Vidal [Phys. Rev. Lett. 99, 220405 (2007).

Solid State Welding Development at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Ding, Robert J.; Walker, Bryant

2012-01-01

What is TSW and USW? TSW is a solid state weld process consisting of an induction coil heating source, a stir rod, and non-rotating containment plates Independent heating, stirring and forging controls Decouples the heating, stirring and forging process elements of FSW. USW is a solid state weld process consisting of an induction coil heating source, a stir rod, and a non-rotating containment plate; Ultrasonic energy integrated into non-rotating containment plate and stir rod; Independent heating, stirring and forging controls; Decouples the heating, stirring and forging process elements of FSW.

Decoupled temporal patterns of evolution and ecology in two post-Paleozoic clades

NASA Technical Reports Server (NTRS)

McKinney, F. K.; Lidgard, S.; Sepkoski, J. J. Jr; Taylor, P. D.

1998-01-01

Counts of taxonomic diversity are the prevailing standards for documenting large-scale patterns of evolution in the fossil record. However, the secular pattern of relative ecological importance between the bryozoan clades Cyclostomata and Cheilostomata is not reflected fully in compilations of generic diversity or within-fauna species richness, and the delayed ecological recovery of the Cheilostomata after the mass extinction at the Cretaceous-Tertiary boundary is missed entirely. These observations demonstrate that evolutionary success and ecological dominance can be decoupled and profoundly different, even over tens of millions of years.

Vibration control of large linear quadratic symmetric systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Jeon, G. J.

1983-01-01

Some unique properties on a class of the second order lambda matrices were found and applied to determine a damping matrix of the decoupled subsystem in such a way that the damped system would have preassigned eigenvalues without disturbing the stiffness matrix. The resulting system was realized as a time invariant velocity only feedback control system with desired poles. Another approach using optimal control theory was also applied to the decoupled system in such a way that the mode spillover problem could be eliminated. The procedures were tested successfully by numerical examples.

CGILS Phase 2 LES intercomparison of response of subtropical marine low cloud regimes to CO 2 quadrupling and a CMIP3 composite forcing change: Large eddy simulation of cloud feedbacks

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

Blossey, Peter N.; Bretherton, Christopher S.; Cheng, Anning

We extended Phase 1 of the CGILS large-eddy simulation (LES) intercomparison in order to understand if subtropical marine boundary-layer clouds respond to idealized climate perturbations consistently in six LES models. Here the responses to quadrupled carbon dioxide (“fast adjustment”) and to a composite climate perturbation representative of CMIP3 multimodel mean 2×CO 2 near-equilibrium conditions are analyzed. As in Phase 1, the LES is run to equilibrium using specified steady summertime forcings representative of three locations in the Northeast Pacific Ocean in shallow well-mixed stratocumulus, decoupled stratocumulus, and shallow cumulus cloud regimes. Our results are generally consistent with a single-LES studymore » of Bretherton et al. (2013) on which this intercomparison was based. Both quadrupled CO 2 and the composite climate perturbation result in less cloud and a shallower boundary layer for all models in well-mixed stratocumulus and for all but a single LES in decoupled stratocumulus and shallow cumulus, corroborating similar findings from global climate models (GCMs). For both perturbations, the amount of cloud reduction varies across the models, but there is less intermodel scatter than in GCMs. Furthermore, the cloud radiative effect changes are much larger in the stratocumulus-capped regimes than in the shallow cumulus regime, for which precipitation buffering may damp the cloud response. In the decoupled stratocumulus and cumulus regimes, both the CO 2 increase and CMIP3 perturbations reduce boundary-layer decoupling, due to the shallowing of inversion height.« less

CGILS Phase 2 LES intercomparison of response of subtropical marine low cloud regimes to CO 2 quadrupling and a CMIP3 composite forcing change: Large eddy simulation of cloud feedbacks

DOE PAGES

Blossey, Peter N.; Bretherton, Christopher S.; Cheng, Anning; ...

2016-10-27

We extended Phase 1 of the CGILS large-eddy simulation (LES) intercomparison in order to understand if subtropical marine boundary-layer clouds respond to idealized climate perturbations consistently in six LES models. Here the responses to quadrupled carbon dioxide (“fast adjustment”) and to a composite climate perturbation representative of CMIP3 multimodel mean 2×CO 2 near-equilibrium conditions are analyzed. As in Phase 1, the LES is run to equilibrium using specified steady summertime forcings representative of three locations in the Northeast Pacific Ocean in shallow well-mixed stratocumulus, decoupled stratocumulus, and shallow cumulus cloud regimes. Our results are generally consistent with a single-LES studymore » of Bretherton et al. (2013) on which this intercomparison was based. Both quadrupled CO 2 and the composite climate perturbation result in less cloud and a shallower boundary layer for all models in well-mixed stratocumulus and for all but a single LES in decoupled stratocumulus and shallow cumulus, corroborating similar findings from global climate models (GCMs). For both perturbations, the amount of cloud reduction varies across the models, but there is less intermodel scatter than in GCMs. Furthermore, the cloud radiative effect changes are much larger in the stratocumulus-capped regimes than in the shallow cumulus regime, for which precipitation buffering may damp the cloud response. In the decoupled stratocumulus and cumulus regimes, both the CO 2 increase and CMIP3 perturbations reduce boundary-layer decoupling, due to the shallowing of inversion height.« less

What makes us think? A three-stage dual-process model of analytic engagement.

PubMed

Pennycook, Gordon; Fugelsang, Jonathan A; Koehler, Derek J

2015-08-01

The distinction between intuitive and analytic thinking is common in psychology. However, while often being quite clear on the characteristics of the two processes ('Type 1' processes are fast, autonomous, intuitive, etc. and 'Type 2' processes are slow, deliberative, analytic, etc.), dual-process theorists have been heavily criticized for being unclear on the factors that determine when an individual will think analytically or rely on their intuition. We address this issue by introducing a three-stage model that elucidates the bottom-up factors that cause individuals to engage Type 2 processing. According to the model, multiple Type 1 processes may be cued by a stimulus (Stage 1), leading to the potential for conflict detection (Stage 2). If successful, conflict detection leads to Type 2 processing (Stage 3), which may take the form of rationalization (i.e., the Type 1 output is verified post hoc) or decoupling (i.e., the Type 1 output is falsified). We tested key aspects of the model using a novel base-rate task where stereotypes and base-rate probabilities cued the same (non-conflict problems) or different (conflict problems) responses about group membership. Our results support two key predictions derived from the model: (1) conflict detection and decoupling are dissociable sources of Type 2 processing and (2) conflict detection sometimes fails. We argue that considering the potential stages of reasoning allows us to distinguish early (conflict detection) and late (decoupling) sources of analytic thought. Errors may occur at both stages and, as a consequence, bias arises from both conflict monitoring and decoupling failures. Copyright © 2015 Elsevier Inc. All rights reserved.

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

NASA Astrophysics Data System (ADS)

Kunz, Barbara E.; Regis, Daniele; Engi, Martin

2018-03-01

Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U-Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P-T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U-Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure.

Affective experience and motivated behavior in schizophrenia spectrum disorders: Evidence from clinical and nonclinical samples.

PubMed

Lui, Simon S Y; Shi, Yan-Fang; Au, Angie C W; Li, Zhi; Tsui, Chi F; Chan, Constance K Y; Leung, Meranda M W; Wong, Peony T Y; Wang, Yi; Yan, Chao; Heerey, Erin A; Cheung, Eric F C; Chan, Raymond C K

2016-09-01

Individuals with schizophrenia have been found to exhibit emotion-behavior decoupling, particularly with respect to anticipated, rather than experienced events. However, previous research has focused on how emotion valence translates into motivated behavior, ignoring the fact that emotion arousal should also modulate emotion-behavior coupling. Few studies have examined emotion-behavior coupling in prepsychotic conditions. This investigation aimed to examine the nature and extent of emotion valence- and arousal-behavior coupling across the schizophrenia spectrum. We examine how emotional valence and arousal couple with behavior in 3 groups of individuals (25 individuals with chronic schizophrenia; 27 individuals early in the disease course, and 31 individuals reporting negative schizotypal symptoms). Participants completed a task using slides to elicit emotion and evoke motivated behavior. We compared participants with their respective matched control groups to determine differences in the correspondence between self-reported emotion valence/arousal and motivated behavior. Both groups with schizophrenia reported similar affective experiences as their controls, whereas individuals reporting negative schizotypal symptoms showed "in-the-moment" anhedonia but not emotion-behavior decoupling. In addition, the schizophrenia groups' affective experiences corresponded less well to their behavior relative to controls. Our findings suggest emotion-behavior decoupling along both valence and arousal dimensions in schizophrenia but not in participants with high levels of schizotypal symptoms. Findings appear to support the idea that emotion-behavior decoupling differs in nature and extent across the schizophrenia spectrum. Interventions to recouple emotion and behavior may be particularly helpful in allowing people with schizophrenia to gain functional independence. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Generation of real-time mode high-resolution water vapor fields from GPS observations

NASA Astrophysics Data System (ADS)

Yu, Chen; Penna, Nigel T.; Li, Zhenhong

2017-02-01

Pointwise GPS measurements of tropospheric zenith total delay can be interpolated to provide high-resolution water vapor maps which may be used for correcting synthetic aperture radar images, for numeral weather prediction, and for correcting Network Real-time Kinematic GPS observations. Several previous studies have addressed the importance of the elevation dependency of water vapor, but it is often a challenge to separate elevation-dependent tropospheric delays from turbulent components. In this paper, we present an iterative tropospheric decomposition interpolation model that decouples the elevation and turbulent tropospheric delay components. For a 150 km × 150 km California study region, we estimate real-time mode zenith total delays at 41 GPS stations over 1 year by using the precise point positioning technique and demonstrate that the decoupled interpolation model generates improved high-resolution tropospheric delay maps compared with previous tropospheric turbulence- and elevation-dependent models. Cross validation of the GPS zenith total delays yields an RMS error of 4.6 mm with the decoupled interpolation model, compared with 8.4 mm with the previous model. On converting the GPS zenith wet delays to precipitable water vapor and interpolating to 1 km grid cells across the region, validations with the Moderate Resolution Imaging Spectroradiometer near-IR water vapor product show 1.7 mm RMS differences by using the decoupled model, compared with 2.0 mm for the previous interpolation model. Such results are obtained without differencing the tropospheric delays or water vapor estimates in time or space, while the errors are similar over flat and mountainous terrains, as well as for both inland and coastal areas.

Decoupling of Local Metabolic Activity and Functional Connectivity Links to Amyloid in Alzheimer's Disease.

PubMed

Scherr, Martin; Pasquini, Lorenzo; Benson, Gloria; Nuttall, Rachel; Gruber, Martin; Neitzel, Julia; Brandl, Felix; Sorg, Christian

2018-05-19

Both ongoing local metabolic activity (LMA) and corresponding functional connectivity (FC) with remote brain regions are progressively impaired in Alzheimer's disease (AD), particularly in the posterior default mode network (pDMN); however, it is unknown how these impairments interact. It is well known that decreasing mean synaptic activity of a region, i.e., decreasing LMA, reduces the region's sensitivity to afferent input from other regions, i.e., FC. We hypothesized progressive decoupling between LMA and FC in AD, which is linked to amyloid-β pathology (Aβ). Healthy adults (n=20) and Aβ+patients without memory impairment (n=9), early MCI (n=21), late MCI (n=18) and AD (n=22) were assessed by resting-state fMRI, FDG-PET, and AV-45-PET to measure FC, LMA, and Aβ of the pDMN. Coupling between LMA and FC (rLA/FC) was estimated by voxelwise correlation. RLMA/FC decreased with disease severity (F=20.09, p<0.001). This decrease was specifically associated with pDMN Aβ (r=-0.273, p=0.029) but not global Aβ (r=-0.112, p=0.378) and with the impact of Aβ on FC (i.e., rAβ/FC,r=-0.339; p=0.006). In multiple regression models rLMA/FC was also associated with memory impairment, reduced cognitive speed and flexibility, outperforming global Aβ, pDMN Aβ, pDMN LMA, and pDMN FC, respectively. Results demonstrate increasing decoupling of LMA from its FC in AD. Data suggest that decoupling is driven by local Aβ and contributes to memory decline.

Two-degrees-of-freedom piezo-driven fast steering mirror with cross-axis decoupling capability

NASA Astrophysics Data System (ADS)

Shao, Shubao; Tian, Zheng; Song, Siyang; Xu, Minglong

2018-05-01

Because mechanical cross coupling between its axes would lead to degradation of the scanning precision of a piezo-driven fast steering mirror (PFSM), a two-degrees-of-freedom (2-DoF) PFSM with a cross-axis decoupling capability, in which 2-DoF flexure hinges are used, is proposed in this work. The overall structure of the proposed PFSM is first introduced and then both static and dynamic models are established analytically; in addition, the decoupling mechanism is described in detail and the low dynamic cross coupling ratios that occur between the two DoFs are shown. Because of the decoupling property of the PFSM, the 2-DoF motion is treated as a combination of two independent one-degree-of-freedom (1-DoF) motions and two independent proportional-integral-derivative controllers are thus used separately in the control of the two DoFs. Based on this control strategy, experiments involving both 1-DoF trajectory tracking and 2-DoF trajectory tracking are implemented. The test results show that the proposed PFSM can achieve the tilt range of ±7 mrad for both axes with the low coupling ratios that are less than 2% (-34 dB), and the bandwidths of both axes are higher than 810 Hz; in addition, the maximal tracking full scale range errors for 1-DoF trajectory tracking and 2-DoF trajectory tracking are less than 0.2% and 1%, respectively, where the larger error of 2-DoF trajectory tracking is mainly caused by the remaining cross coupling between axes.

Textile Inspired Lithium-Oxygen Battery Cathode with Decoupled Oxygen and Electrolyte Pathways.

PubMed

Xu, Shaomao; Yao, Yonggang; Guo, Yuanyuan; Zeng, Xiaoqiao; Lacey, Steven D; Song, Huiyu; Chen, Chaoji; Li, Yiju; Dai, Jiaqi; Wang, Yanbin; Chen, Yanan; Liu, Boyang; Fu, Kun; Amine, Khalil; Lu, Jun; Hu, Liangbing

2018-01-01

The lithium-air (Li-O 2 ) battery has been deemed one of the most promising next-generation energy-storage devices due to its ultrahigh energy density. However, in conventional porous carbon-air cathodes, the oxygen gas and electrolyte often compete for transport pathways, which limit battery performance. Here, a novel textile-based air cathode is developed with a triple-phase structure to improve overall battery performance. The hierarchical structure of the conductive textile network leads to decoupled pathways for oxygen gas and electrolyte: oxygen flows through the woven mesh while the electrolyte diffuses along the textile fibers. Due to noncompetitive transport, the textile-based Li-O 2 cathode exhibits a high discharge capacity of 8.6 mAh cm -2 , a low overpotential of 1.15 V, and stable operation exceeding 50 cycles. The textile-based structure can be applied to a range of applications (fuel cells, water splitting, and redox flow batteries) that involve multiple phase reactions. The reported decoupled transport pathway design also spurs potential toward flexible/wearable Li-O 2 batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Is an off-task mind a freely-moving mind? Examining the relationship between different dimensions of thought.

PubMed

Mills, Caitlin; Raffaelli, Quentin; Irving, Zachary C; Stan, Dylan; Christoff, Kalina

2018-02-01

Mind wandering is frequently defined as task-unrelated or perceptually decoupled thought. However, these definitions may not capture the dynamic features of a wandering mind, such as its tendency to 'move freely'. Here we test the relationship between three theoretically dissociable dimensions of thought: freedom of movement in thought, task-relatedness, and perceptual decoupling (i.e., lack of awareness of surroundings). Using everyday life experience sampling, thought probes were randomly delivered to participants' phones for ten days. Results revealed weak intra-individual correlations between freedom of movement in thought and task-unrelatedness, as well as perceptual decoupling. Within our dataset, over 40% of thoughts would have been misclassified under the assumption that off-task thought is inherently freely moving. Overall, freedom of movement appears to be an independent dimension of thought that is not captured by the two most common measures of mind wandering. Future work focusing on the dynamics of thought may be crucial for improving our understanding of the wandering mind. Copyright © 2017 Elsevier Inc. All rights reserved.

A Two-Layer Gene Circuit for Decoupling Cell Growth from Metabolite Production.

PubMed

Lo, Tat-Ming; Chng, Si Hui; Teo, Wei Suong; Cho, Han-Saem; Chang, Matthew Wook

2016-08-01

We present a synthetic gene circuit for decoupling cell growth from metabolite production through autonomous regulation of enzymatic pathways by integrated modules that sense nutrient and substrate. The two-layer circuit allows Escherichia coli to selectively utilize target substrates in a mixed pool; channel metabolic resources to growth by delaying enzymatic conversion until nutrient depletion; and activate, terminate, and re-activate conversion upon substrate availability. We developed two versions of controller, both of which have glucose nutrient sensors but differ in their substrate-sensing modules. One controller is specific for hydroxycinnamic acid and the other for oleic acid. Our hydroxycinnamic acid controller lowered metabolic stress 2-fold and increased the growth rate 2-fold and productivity 5-fold, whereas our oleic acid controller lowered metabolic stress 2-fold and increased the growth rate 1.3-fold and productivity 2.4-fold. These results demonstrate the potential for engineering strategies that decouple growth and production to make bio-based production more economical and sustainable. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

A high-order Lagrangian-decoupling method for the incompressible Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Ho, Lee-Wing; Maday, Yvon; Patera, Anthony T.; Ronquist, Einar M.

1989-01-01

A high-order Lagrangian-decoupling method is presented for the unsteady convection-diffusion and incompressible Navier-Stokes equations. The method is based upon: (1) Lagrangian variational forms that reduce the convection-diffusion equation to a symmetric initial value problem; (2) implicit high-order backward-differentiation finite-difference schemes for integration along characteristics; (3) finite element or spectral element spatial discretizations; and (4) mesh-invariance procedures and high-order explicit time-stepping schemes for deducing function values at convected space-time points. The method improves upon previous finite element characteristic methods through the systematic and efficient extension to high order accuracy, and the introduction of a simple structure-preserving characteristic-foot calculation procedure which is readily implemented on modern architectures. The new method is significantly more efficient than explicit-convection schemes for the Navier-Stokes equations due to the decoupling of the convection and Stokes operators and the attendant increase in temporal stability. Numerous numerical examples are given for the convection-diffusion and Navier-Stokes equations for the particular case of a spectral element spatial discretization.

Global Sliding Mode Control for the Bank-to-Turn of Hypersonic Glide Vehicle

NASA Astrophysics Data System (ADS)

Zhang, J.; Yu, Y. F.; Yan, P. P.; Fan, Y. H.; Guo, X. W.

2017-03-01

The technology of Bank-to-Turn has been recognized as an attractive direction due to their significance for the control of hypersonic glide vehicle. Strong coupling existing among pitch, yaw and roll channel was a great challenge for banking to turn, and thus a novel global sliding mode controller was designed for hypersonic glider in this paper. Considering the coupling among channels as interference, we can use invariance principle of sliding mode motion to realize the decoupling control. The global sliding mode control system could eliminate the stage of reaching, which can lead to the realization of whole systematic process decoupling control. When the global sliding mode factor was designed, a minimum norm pole assignment method of the sliding mode matrix was introduced to improve the robustness of the system. The method of continuity of symbolic function was adopted to overcome the chatter, which furtherly modify the transient performance of the system. The simulation results show that this method has good performance of three channel decoupling control and guidance command tracking. And it can meet the requirements of the dynamic performance of the system.

SKATE: a docking program that decouples systematic sampling from scoring.

PubMed

Feng, Jianwen A; Marshall, Garland R

2010-11-15

SKATE is a docking prototype that decouples systematic sampling from scoring. This novel approach removes any interdependence between sampling and scoring functions to achieve better sampling and, thus, improves docking accuracy. SKATE systematically samples a ligand's conformational, rotational and translational degrees of freedom, as constrained by a receptor pocket, to find sterically allowed poses. Efficient systematic sampling is achieved by pruning the combinatorial tree using aggregate assembly, discriminant analysis, adaptive sampling, radial sampling, and clustering. Because systematic sampling is decoupled from scoring, the poses generated by SKATE can be ranked by any published, or in-house, scoring function. To test the performance of SKATE, ligands from the Asetex/CDCC set, the Surflex set, and the Vertex set, a total of 266 complexes, were redocked to their respective receptors. The results show that SKATE was able to sample poses within 2 A RMSD of the native structure for 98, 95, and 98% of the cases in the Astex/CDCC, Surflex, and Vertex sets, respectively. Cross-docking accuracy of SKATE was also assessed by docking 10 ligands to thymidine kinase and 73 ligands to cyclin-dependent kinase. 2010 Wiley Periodicals, Inc.

Determination of NH proton chemical shift anisotropy with 14N-1H heteronuclear decoupling using ultrafast magic angle spinning solid-state NMR

NASA Astrophysics Data System (ADS)

Pandey, Manoj Kumar; Nishiyama, Yusuke

2015-12-01

The extraction of chemical shift anisotropy (CSA) tensors of protons either directly bonded to 14N nuclei (I = 1) or lying in their vicinity using rotor-synchronous recoupling pulse sequence is always fraught with difficulty due to simultaneous recoupling of 14N-1H heteronuclear dipolar couplings and the lack of methods to efficiently decouple these interactions. This difficulty mainly arises from the presence of large 14N quadrupolar interactions in comparison to the rf field that can practically be achieved. In the present work it is demonstrated that the application of on-resonance 14N-1H decoupling with rf field strength ∼30 times weaker than the 14N quadrupolar coupling during 1H CSA recoupling under ultrafast MAS (90 kHz) results in CSA lineshapes that are free from any distortions from recoupled 14N-1H interactions. With the use of extensive numerical simulations we have shown the applicability of our proposed method on a naturally abundant L-Histidine HCl·H2O sample.

Advanced Control Synthesis for Reverse Osmosis Water Desalination Processes.

PubMed

Phuc, Bui Duc Hong; You, Sam-Sang; Choi, Hyeung-Six; Jeong, Seok-Kwon

2017-11-01

  In this study, robust control synthesis has been applied to a reverse osmosis desalination plant whose product water flow and salinity are chosen as two controlled variables. The reverse osmosis process has been selected to study since it typically uses less energy than thermal distillation. The aim of the robust design is to overcome the limitation of classical controllers in dealing with large parametric uncertainties, external disturbances, sensor noises, and unmodeled process dynamics. The analyzed desalination process is modeled as a multi-input multi-output (MIMO) system with varying parameters. The control system is decoupled using a feed forward decoupling method to reduce the interactions between control channels. Both nominal and perturbed reverse osmosis systems have been analyzed using structured singular values for their stabilities and performances. Simulation results show that the system responses meet all the control requirements against various uncertainties. Finally the reduced order controller provides excellent robust performance, with achieving decoupling, disturbance attenuation, and noise rejection. It can help to reduce the membrane cleanings, increase the robustness against uncertainties, and lower the energy consumption for process monitoring.

Global Model for Asymmetric, Diode-Type Dual Frequency Capacitive Discharge

NASA Astrophysics Data System (ADS)

Kim, Jisoo; Lieberman, M. A.; Lichtenberg, A. J.

2003-10-01

Dual frequency capacitive reactors can have desirable properties for dielectric etch: low cost, robust uniformity over large areas, and control of dissociation. In the ideal case, the high frequency power controls the plasma density (ion flux) and the low frequency voltage controls the ion bombarding energy. Typical operating conditions are: discharge radius 15-30 cm, length 1-3 cm, pressure 30-200 mTorr, high frequency 27.1-160 MHz, low frequency 2-13.6 MHz, and powers of 500-3000 W for both high and low frequencies. The decoupling of the high and low frequencies is an important feature of dual frequency capacitive discharges. In this work, we describe a global (volume-averaged) model having different top and bottom plate areas that incorporates particle balance, and ohmic and stochastic heating for high and low frequencies. The model is used to obtain the decoupling of high and low frequencies and to investigate limitations to ideal decoupling. Support provided by Lam Research, NSF Grant ECS-0139956, California industries, and UC-SMART Contract SM99-10051.

Trap Design and Construction for High-Power Multinuclear Magnetic Resonance Experiments

PubMed Central

Rispoli, Joseph V.; Dimitrov, Ivan E.; Cheshkov, Sergey; Malloy, Craig; Wright, Steven M.; McDougall, Mary P.

2016-01-01

Performing multinuclear experiments requires one or more radiofrequency (RF) coils operating at both the proton and second-nucleus frequencies; however, inductive coupling between coils must be mitigated to retain proton sensitivity and coil tuning stability. The inclusion of trap circuits simplifies placement of multinuclear RF coils while maintaining inter-element isolation. Of the commonly investigated non-proton nuclei, perhaps the most technically demanding is carbon-13, particularly when applying a proton decoupling scheme to improve the resulting spectra. This work presents experimental data for trap circuits withstanding high-power broadband proton decoupling of carbon-13 at 7 T. The advantages and challenges of building trap circuits with various inductor and capacitor components are discussed. Multiple trap designs are evaluated on the bench and utilized on an RF coil at 7 T to detect broadband proton-decoupled carbon-13 spectra from a lipid phantom. A particular trap design, built from a coaxial stub inductor and high-voltage ceramic chip capacitors, is highlighted owing to both its performance and adaptability for planar array coil elements with diverse spatial orientations. PMID:28529464

Decoupling of reaction time-related default mode network activity with cognitive demand.

PubMed

Barber, Anita D; Caffo, Brian S; Pekar, James J; Mostofsky, Stewart H

2017-06-01

Reaction Time (RT) is associated with increased amplitude of the Blood Oxygen-Level Dependent (BOLD) response in task positive regions. Few studies have focused on whether opposing RT-related suppression of task activity also occurs. The current study used two Go/No-go tasks with different cognitive demands to examine regions that showed greater BOLD suppression for longer RT trials. These RT-related suppression effects occurred within the DMN and were task-specific, localizing to separate regions for the two tasks. In the task requiring working memory, RT-related de-coupling of the DMN occurred. This was reflected by opposing RT-BOLD effects for different DMN regions, as well as by reduced positive RT-related Psycho-Physiological Interaction (PPI) connectivity within the DMN and a lack of negative RT-related PPI connectivity between DMN and task positive regions. The results suggest that RT-related DMN suppression is task-specific. RT-related de-coupling of the DMN with more complex task demands may contribute to lapses of attention and performance decrements that occur during cognitively-demanding tasks.

Fierz Convergence Criterion: A Controlled Approach to Strongly Interacting Systems with Small Embedded Clusters.

PubMed

Ayral, Thomas; Vučičević, Jaksa; Parcollet, Olivier

2017-10-20

We present an embedded-cluster method, based on the triply irreducible local expansion formalism. It turns the Fierz ambiguity, inherent to approaches based on a bosonic decoupling of local fermionic interactions, into a convergence criterion. It is based on the approximation of the three-leg vertex by a coarse-grained vertex computed from a self-consistently determined cluster impurity model. The computed self-energies are, by construction, continuous functions of momentum. We show that, in three interaction and doping regimes of the two-dimensional Hubbard model, self-energies obtained with clusters of size four only are very close to numerically exact benchmark results. We show that the Fierz parameter, which parametrizes the freedom in the Hubbard-Stratonovich decoupling, can be used as a quality control parameter. By contrast, the GW+extended dynamical mean field theory approximation with four cluster sites is shown to yield good results only in the weak-coupling regime and for a particular decoupling. Finally, we show that the vertex has spatially nonlocal components only at low Matsubara frequencies.

Thin-film decoupling capacitors for multi-chip modules

NASA Astrophysics Data System (ADS)

Dimos, D.; Lockwood, S. J.; Schwartz, R. W.; Rogers, M. S.

Thin-film decoupling capacitors based on ferroelectric lead lanthanum zirconate titanate (PLZT) films are being developed for use in advanced packages, such as multi-chip modules. These thin-film decoupling capacitors are intended to replace multi-layer ceramic capacitors for certain applications, since they can be more fully integrated into the packaging architecture. The increased integration that can be achieved should lead to decreased package volume and improved high-speed performance, due to a decrease in interconnect inductance. PLZT films are fabricated by spin coating using metal carboxylate/alkoxide solutions. These films exhibit very high dielectric constants ((var epsilon) greater than or equal to 900), low dielectric losses (tan(delta) = 0.01), excellent insulation resistances (rho greater than 10(exp 13) (Omega)-cm at 125 C), and good breakdown field strengths (E(sub B) = 900 kV/cm). For integrated circuit applications, the PLZT dielectric is less than 1 micron thick, which results in a large capacitance/area (8-9 nF/sq mm). The thin-film geometry and processing conditions also make these capacitors suitable for direct incorporation onto integrated circuits and for packages that require embedded components.

Decoupling of critical temperature and superconducting gaps in irradiated films of a Fe-based superconductor

NASA Astrophysics Data System (ADS)

Daghero, Dario; Tortello, Mauro; Ummarino, Giovanni A.; Piatti, Erik; Ghigo, Gianluca; Hatano, Takafumi; Kawaguchi, Takahiko; Ikuta, Hiroshi; Gonnelli, Renato S.

2018-07-01

We report on direct measurements of the energy gaps (carried out by means of point-contact Andreev reflection spectroscopy, PCARS) and of the critical temperature in thin, optimally doped, epitaxial films of BaFe2(As1-x P x )2 irradiated with 250 MeV Au ions. The low-temperature PCARS spectra (taken with the current flowing along the c axis) can be fitted by a modified Blonder-Tinkham-Klapwijk model with two nodeless gaps; this is not in contrast with the possible presence of node lines suggested by various experiments in literature. Up to a fluence Φ = 7.3 × 1011 cm-2, we observe a monotonic suppression of the critical temperature and of the gap amplitudes Δ1 and Δ2. Interestingly, while T c decreases by about 3%, the gaps decrease much more (by about 37% and 25% respectively), suggesting a decoupling between high-temperature and low-temperature superconducting properties. An explanation for this finding is proposed within an effective two-band Eliashberg model, in which such decoupling is inherently associated to defects created by irradiation.

Decentralized control of large flexible structures by joint decoupling

NASA Technical Reports Server (NTRS)

Su, Tzu-Jeng; Juang, Jer-Nan

1992-01-01

A decentralized control design method is presented for large complex flexible structures by using the idea of joint decoupling. The derivation is based on a coupled substructure state-space model, which is obtained from enforcing conditions of interface compatibility and equilibrium to the substructure state-space models. It is shown that by restricting the control law to be localized state feedback and by setting the joint actuator input commands to decouple joint 'degrees of freedom' (dof) from interior dof, the global structure control design problem can be decomposed into several substructure control design problems. The substructure control gains and substructure observers are designed based on modified substructure state-space models. The controllers produced by the proposed method can operate successfully at the individual substructure level as well as at the global structure level. Therefore, not only control design but also control implementation is decentralized. Stability and performance requirement of the closed-loop system can be achieved by using any existing state feedback control design method. A two-component mass-spring damper system and a three-truss structure are used as examples to demonstrate the proposed method.

Apparatus for decoupled thermo-photocatalytic pollution control

DOEpatents

Tabatabaie-Raissi, Ali; Muradov, Nazim Z.; Martin, Eric

2003-04-22

A new method for design and scale-up of photocatalytic and thermocatalytic processes is disclosed. The method is based on optimizing photoprocess energetics by decoupling of the process energy efficiency from the DRE for target contaminants. The technique is applicable to photo-thermocatalytic reactor design and scale-up. At low irradiance levels, the method is based on the implementation of low pressure drop biopolymeric and synthetic polymeric support for titanium dioxide and other band-gap media. At high irradiance levels, the method utilizes multifunctional metal oxide aerogels and other media within a novel rotating fluidized particle bed reactor.

Effect of neutrino rest mass on ionization equilibrium freeze-out

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

Grohs, Evan Bradley; Fuller, George M.; Kishimoto, Chad T.

2015-12-23

We show how small neutrino rest masses can increase the expansion rate near the photon decoupling epoch in the early Universe, causing an earlier, higher temperature freeze-out for ionization equilibrium compared to the massless neutrino case. This yields a larger free-electron fraction, thereby affecting the photon diffusion length differently than the sound horizon at photon decoupling. This neutrino-mass and recombination effect depends strongly on the neutrino rest masses. Ultimately, though below current sensitivity, this effect could be probed by next-generation cosmic microwave background experiments, giving another observational handle on neutrino rest mass.

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

Matvejeff, M., E-mail: mikko.matvejeff@picosun.com; Department of Chemistry, Aalto University, Kemistintie 1, 02150 Espoo; Ahvenniemi, E.

We study magnetic coupling between hole-doped manganite layers separated by either a perovskite or a rock-salt barrier of variable thickness. Both the type and the quality of the interface have a strong impact on the minimum critical barrier thickness where the manganite layers become magnetically decoupled. A rock-salt barrier layer only 1 unit cell (0.5 nm) thick remains insulating and is able to magnetically de-couple the electrode layers. The technique can therefore be used for developing high-performance planar oxide electronic devices such as magnetic tunnel junctions and quantum well structures that depend on magnetically and electronically sharp heterointerfaces.

Partial structure factors reveal atomic dynamics in metallic alloy melts

NASA Astrophysics Data System (ADS)

Nowak, B.; Holland-Moritz, D.; Yang, F.; Voigtmann, Th.; Kordel, T.; Hansen, T. C.; Meyer, A.

2017-07-01

We investigate the dynamical decoupling of the diffusion coefficients of the different components in a metallic alloy melt, using a combination of neutron diffraction, isotopic substitution, and electrostatic levitation in Zr-Ni melts. We show that excess Ni atoms can diffuse more freely in a background of saturated chemical interaction, causing their dynamics to become much faster and thus decoupled than anticipated from the interparticle interactions. Based on the mode-coupling theory of the glass transition, the averaged structure as given by the partial static structure factors is able to explain the observed dynamical behavior.

Synthetic clock states generated in a Bose-Einstein condensate via continuous dynamical decoupling

NASA Astrophysics Data System (ADS)

Lundblad, Nathan; Trypogeorgos, Dimitrios; Valdes-Curiel, Ana; Marshall, Erin; Spielman, Ian

2017-04-01

Radiofrequency- or microwave-dressed states have been used in NV center and ion-trap experiments to extend coherence times, shielding qubits from magnetic field noise through a process known as continuous dynamical decoupling. Such field-insensitive dressed states, as applied in the context of ultracold neutral atoms, have applications related to the creation of novel phases of spin-orbit-coupled quantum matter. We present observations of such a protected dressed-state system in a Bose-Einstein condensate, including measurements of the dependence of the protection on rf coupling strength, and estimates of residual field sensitivities.

The spectrum of density perturbations in an expanding universe

NASA Technical Reports Server (NTRS)

Silk, J.

1974-01-01

The basic dynamic equations that govern the evolution of perturbations in a Friedmann-Lemaitre universe are derived. General solutions describing the evolution of adiabatic perturbations in the density of matter are obtained, and the choice of the appropriate initial conditions is examined. The various perturbation modes are compared, and the effects of decoupling on the perturbation spectrum are studied. The scheme used to follow the evolution of density perturbations through decoupling is based on an extension of the Eddington approximation to the radiative transfer equation, and is strictly valid in both optically thick and thin limits.

Equicontrollability and its application to model-following and decoupling.

NASA Technical Reports Server (NTRS)

Curran, R. T.

1971-01-01

Discussion of 'model following,' a term used to describe a class of problems characterized by having two dynamic systems, generically known as the 'plant' and the 'model,' it being required to find a controller to attach to the plant so as to make the resultant compensated system behave, in an input/output sense, in the same way as the model. The approach presented to the problem takes a structural point of view. The result is a complex but informative definition which solves the problem as posed. The application of both the algorithm and its basis, equicontrollability, to the decoupling problem is considered.

Electric field-decoupled electroosmotic pump for microfluidic devices.

PubMed

Liu, Shaorong; Pu, Qiaosheng; Lu, Joann J

2003-09-26

An electric field-free electroosmotic pump has been constructed and its pumping rate has been measured under various experimental conditions. The key component of the pump is an ion-exchange membrane grounding joint that serves two major functions: (i) to maintain fluid continuity between pump channels and microfluidic conduit and (ii) to ground the solution in the microfluidic channel at the joint through an external electrode, and hence to decouple the electric field applied to the pump channels from the rest of the microfluidic system. A theoretical model has been developed to calculate the pumping rates and its validity has been demonstrated.

Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

DOE PAGES

Gallmeier, F. X.; Lu, W.; Riemer, B. W.; ...

2016-06-14

We identified candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared tomore » the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm 2 to 20 × 20 mm 2. Furthermore, this increase in brightness has the potential to translate to an increase of beam intensity at the instruments’ sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. Our first effort decoupled group moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.« less

Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

NASA Astrophysics Data System (ADS)

Gallmeier, F. X.; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L.

2016-06-01

Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm2 to 20 × 20 mm2. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

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

Gallmeier, F. X.; Lu, W.; Riemer, B. W.

We identified candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared tomore » the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm 2 to 20 × 20 mm 2. Furthermore, this increase in brightness has the potential to translate to an increase of beam intensity at the instruments’ sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. Our first effort decoupled group moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.« less

Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

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

Gallmeier, F. X., E-mail: gallmeierfz@ornl.gov; Lu, W.; Riemer, B. W.

Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis comparedmore » to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm{sup 2} to 20 × 20 mm{sup 2}. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments’ sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.« less

Automated smoother for the numerical decoupling of dynamics models.

PubMed

Vilela, Marco; Borges, Carlos C H; Vinga, Susana; Vasconcelos, Ana Tereza R; Santos, Helena; Voit, Eberhard O; Almeida, Jonas S

2007-08-21

Structure identification of dynamic models for complex biological systems is the cornerstone of their reverse engineering. Biochemical Systems Theory (BST) offers a particularly convenient solution because its parameters are kinetic-order coefficients which directly identify the topology of the underlying network of processes. We have previously proposed a numerical decoupling procedure that allows the identification of multivariate dynamic models of complex biological processes. While described here within the context of BST, this procedure has a general applicability to signal extraction. Our original implementation relied on artificial neural networks (ANN), which caused slight, undesirable bias during the smoothing of the time courses. As an alternative, we propose here an adaptation of the Whittaker's smoother and demonstrate its role within a robust, fully automated structure identification procedure. In this report we propose a robust, fully automated solution for signal extraction from time series, which is the prerequisite for the efficient reverse engineering of biological systems models. The Whittaker's smoother is reformulated within the context of information theory and extended by the development of adaptive signal segmentation to account for heterogeneous noise structures. The resulting procedure can be used on arbitrary time series with a nonstationary noise process; it is illustrated here with metabolic profiles obtained from in-vivo NMR experiments. The smoothed solution that is free of parametric bias permits differentiation, which is crucial for the numerical decoupling of systems of differential equations. The method is applicable in signal extraction from time series with nonstationary noise structure and can be applied in the numerical decoupling of system of differential equations into algebraic equations, and thus constitutes a rather general tool for the reverse engineering of mechanistic model descriptions from multivariate experimental time series.

Electric double layer electrostatics of pH-responsive spherical polyelectrolyte brushes in the decoupled regime.

PubMed

Li, Hao; Chen, Guang; Das, Siddhartha

2016-11-01

Understanding the behavior and properties of spherical polyelectrolyte brushes (SPEBs), which are polyelectrolyte brushes grafted to a spherical core, is fundamental to many applications in biomedical, chemical and petroleum engineering as well as in pharmaceutics. In this paper, we study the pH-responsive electrostatics of such SPEBs in the decoupled regime. In the first part of the paper, we derive the scaling conditions in terms of the grafting density of the PEs on the spherical core that ensure that the analysis can be performed in the decoupled regime. In such a regime the elastic and the excluded volume effects of polyelectrolyte brushes (PEBs) can be decoupled from the electrostatic effects associated with the PE charge and the induced EDL. As a consequence the PE brush height, assumed to be dictated by the balance of the elastic and excluded volume effects, can be independent of the electrostatic effects. In the second part, we quantify the pH-responsive electrostatics of the SPEBs - we pinpoint that the radial monomer distribution for a given brush molecule exhibit a non-unique cubic distribution that decays away from the spherical core. Such a monomer distribution ensures that the hydrogen ion concentration is appropriately accounted for in the description of the SPEB thermodynamics. We anticipate that the present analysis, which provides possibly one of the first models for probing the electrostatics of pH-responsive SPEBs in a thermodynamically-consistent framework, will be vital for understanding the behavior of a large number of entities ranging from PE-coated NPs and stealth liposomes to biomolecules like bacteria and viruses. Copyright © 2016 Elsevier B.V. All rights reserved.

Looking good or doing better? Patterns of decoupling in the implementation of clinical directorates.

PubMed

Mascia, Daniele; Morandi, Federica; Cicchetti, Americo

2014-01-01

The interest toward hospital restructuring has risen significantly in recent years. In spite of its potential benefits, often organizational restructuring in health care produces unexpected consequences. Extant research suggests that institutional theory provides a powerful theoretical lens through which hospital restructuring can be described and explained. According to this perspective, the effectiveness of change is strongly related to the extent to which innovative arrangements, tools, or practices are adopted and implemented within hospitals. Whenever these new arrangements require a substantial modification of internal processes and practices, resistance to implementation emerges and organizational change is likely to become neutralized. This study analyzes how hospital organizations engage in decoupling by adopting but not implementing a new organizational model named clinical directorate. We collected primary data on the diffusion of the clinical directorate model, which was mandated by law in the Italian National Health Service to improve hospital services. We surveyed the adoption and implementation of the clinical directorate model by monitoring the presence of clinical governance tools (measures for the quality improvement of hospital services) within single directorates. In particular, we compared hospitals that adopted the model before (early adopters) or after (later adopters) the mandate was introduced. Hospitals were engaged in decoupling by adopting the new arrangement but not implementing internal practices and tools for quality improvement. The introduction of the law significantly affected the decoupling, with late-adopter hospitals being less likely to implement the adopted model. The present research shows that changes in quality improvement processes may vary in relation to policy makers' interventions aimed at boosting the adoption of new hospital arrangements. Hospital administrators need to be aware and identify the institutional changes that might be driven by law to be able to react consistently with expectations of policymakers.

Modal space three-state feedback control for electro-hydraulic servo plane redundant driving mechanism with eccentric load decoupling.

PubMed

Zhao, Jinsong; Wang, Zhipeng; Zhang, Chuanbi; Yang, Chifu; Bai, Wenjie; Zhao, Zining

2018-06-01

The shaking table based on electro-hydraulic servo parallel mechanism has the advantage of strong carrying capacity. However, the strong coupling caused by the eccentric load not only affects the degree of freedom space control precision, but also brings trouble to the system control. A novel decoupling control strategy is proposed, which is based on modal space to solve the coupling problem for parallel mechanism with eccentric load. The phenomenon of strong dynamic coupling among degree of freedom space is described by experiments, and its influence on control design is discussed. Considering the particularity of plane motion, the dynamic model is built by Lagrangian method to avoid complex calculations. The dynamic equations of the coupling physical space are transformed into the dynamic equations of the decoupling modal space by using the weighted orthogonality of the modal main mode with respect to mass matrix and stiffness matrix. In the modal space, the adjustments of the modal channels are independent of each other. Moreover, the paper discusses identical closed-loop dynamic characteristics of modal channels, which will realize decoupling for degree of freedom space, thus a modal space three-state feedback control is proposed to expand the frequency bandwidth of each modal channel for ensuring their near-identical responses in a larger frequency range. Experimental results show that the concept of modal space three-state feedback control proposed in this paper can effectively reduce the strong coupling problem of degree of freedom space channels, which verify the effectiveness of the proposed model space state feedback control strategy for improving the control performance of the electro-hydraulic servo plane redundant driving mechanism. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Structure design and characteristic analysis of micro-nano probe based on six dimensional micro-force measuring principle

NASA Astrophysics Data System (ADS)

Yang, Hong-tao; Cai, Chun-mei; Fang, Chuan-zhi; Wu, Tian-feng

2013-10-01

In order to develop micro-nano probe having error self-correcting function and good rigidity structure, a new micro-nano probe system was developed based on six-dimensional micro-force measuring principle. The structure and working principle of the probe was introduced in detail. The static nonlinear decoupling method was established with BP neural network to do the static decoupling for the dimension coupling existing in each direction force measurements. The optimal parameters of BP neural network were selected and the decoupling simulation experiments were done. The maximum probe coupling rate after decoupling is 0.039% in X direction, 0.025% in Y direction and 0.027% in Z direction. The static measurement sensitivity of the probe can reach 10.76μɛ / mN in Z direction and 14.55μɛ / mN in X and Y direction. The modal analysis and harmonic response analysis under three dimensional harmonic load of the probe were done by using finite element method. The natural frequencies under different vibration modes were obtained and the working frequency of the probe was determined, which is higher than 10000 Hz . The transient response analysis of the probe was done, which indicates that the response time of the probe can reach 0.4 ms. From the above results, it is shown that the developed micro-nano probe meets triggering requirements of micro-nano probe. Three dimension measuring force can be measured precisely by the developed probe, which can be used to predict and correct the force deformation error and the touch error of the measuring ball and the measuring rod.

Band-selective excited ultrahigh resolution PSYCHE-TOCSY: fast screening of organic molecules and complex mixtures.

PubMed

Kakita, Veera Mohana Rao; Vemulapalli, Sahithya Phani Babu; Bharatam, Jagadeesh

2016-04-01

Precise assignments of (1) H atomic sites and establishment of their through-bond COSY or TOCSY connectivity are crucial for molecular structural characterization by using (1) H NMR spectroscopy. However, this exercise is often hampered by signal overlap, primarily because of (1) H-(1) H scalar coupling multiplets, even at typical high magnetic fields. The recent developments in homodecoupling strategies for effectively suppressing the coupling multiplets into nice singlets (pure-shift), particularly, Morris's advanced broadband pure-shift yielded by chirp excitation (PSYCHE) decoupling and ultrahigh resolution PSYCHE-TOCSY schemes, have shown new possibilities for unambiguous structural elucidation of complex organic molecules. The superior broadband PSYCHE-TOCSY exhibits enhanced performance over the earlier TOCSY methods, which however warrants prolonged experimental times due to the requirement of large number of dwell increments along the indirect dimension. Herein, we present fast and band-selective analog of the broadband PSYCHE-TOCSY, which is useful for analyzing complex organic molecules that exhibit characteristic yet crowded spectral regions. The simple pulse scheme relies on band-selective excitation (BSE) followed by PSYCHE homodecoupling in the indirect dimension. The BSE-PSYCHE-TOCSY has been exemplified for Estradiol and a complex carbohydrate mixture comprised of six constituents of closely comparable molecular weights. The experimental times are greatly reduced viz., ~20 fold for Estradiol and ~10 fold for carbohydrate mixture, with respect to the broadband PSYCHE-TOCSY. Furthermore, unlike the earlier homonuclear band-selective decoupling, the BSE-PSYCHE-decoupling provides fully decoupled pure-shift spectra for all the individual chemical sites within the excited band. The BSE-PSYCHE-TOCSY is expected to have significant potential for quick screening of complex organic molecules and mixtures at ultrahigh resolution. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

A novel method for calculating relative free energy of similar molecules in two environments

NASA Astrophysics Data System (ADS)

Farhi, Asaf; Singh, Bipin

2017-03-01

Calculating relative free energies is a topic of substantial interest and has many applications including solvation and binding free energies, which are used in computational drug discovery. However, there remain the challenges of accuracy, simple implementation, robustness and efficiency, which prevent the calculations from being automated and limit their use. Here we present an exact and complete decoupling analysis in which the partition functions of the compared systems decompose into the partition functions of the common and different subsystems. This decoupling analysis is applicable to submolecules with coupled degrees of freedom such as the methyl group and to any potential function (including the typical dihedral potentials), enabling to remove less terms in the transformation which results in a more efficient calculation. Then we show mathematically, in the context of partition function decoupling, that the two compared systems can be simulated separately, eliminating the need to design a composite system. We demonstrate the decoupling analysis and the separate transformations in a relative free energy calculation using MD simulations for a general force field and compare to another calculation and to experimental results. We present a unified soft-core technique that ensures the monotonicity of the numerically integrated function (analytical proof) which is important for the selection of intermediates. We show mathematically that in this soft-core technique the numerically integrated function can be non-steep only when we transform the systems separately, which can simplify the numerical integration. Finally, we show that when the systems have rugged energy landscape they can be equilibrated without introducing another sampling dimension which can also enable to use the simulation results for other free energy calculations.

Meristematic cell proliferation and ribosome biogenesis are decoupled in diamagnetically levitated Arabidopsis seedlings.

PubMed

Manzano, Ana Isabel; Larkin, Oliver J; Dijkstra, Camelia E; Anthony, Paul; Davey, Michael R; Eaves, Laurence; Hill, Richard J A; Herranz, Raul; Medina, F Javier

2013-09-05

Cell growth and cell proliferation are intimately linked in the presence of Earth's gravity, but are decoupled under the microgravity conditions present in orbiting spacecraft. New technologies to simulate microgravity conditions for long-duration experiments, with stable environmental conditions, in Earth-based laboratories are required to further our understanding of the effect of extraterrestrial conditions on the growth, development and health of living matter. We studied the response of transgenic seedlings of Arabidopsis thaliana, containing either the CycB1-GUS proliferation marker or the DR5-GUS auxin-mediated growth marker, to diamagnetic levitation in the bore of a superconducting solenoid magnet. As a control, a second set of seedlings were exposed to a strong magnetic field, but not to levitation forces. A third set was exposed to a strong field and simulated hypergravity (2 g). Cell proliferation and cell growth cytological parameters were measured for each set of seedlings. Nucleolin immunodetection was used as a marker of cell growth. Collectively, the data indicate that these two fundamental cellular processes are decoupled in root meristems, as in microgravity: cell proliferation was enhanced whereas cell growth markers were depleted. These results also demonstrated delocalisation of auxin signalling in the root tip despite the fact that levitation of the seedling as a whole does not prevent the sedimentation of statoliths in the root cells. In our model system, we found that diamagnetic levitation led to changes that are very similar to those caused by real- [e.g. on board the International Space Station (ISS)] or mechanically-simulated microgravity [e.g. using a Random Positioning Machine (RPM)]. These changes decoupled meristematic cell proliferation from ribosome biogenesis, and altered auxin polar transport.

Meristematic cell proliferation and ribosome biogenesis are decoupled in diamagnetically levitated Arabidopsis seedlings

PubMed Central

2013-01-01

Background Cell growth and cell proliferation are intimately linked in the presence of Earth’s gravity, but are decoupled under the microgravity conditions present in orbiting spacecraft. New technologies to simulate microgravity conditions for long-duration experiments, with stable environmental conditions, in Earth-based laboratories are required to further our understanding of the effect of extraterrestrial conditions on the growth, development and health of living matter. Results We studied the response of transgenic seedlings of Arabidopsis thaliana, containing either the CycB1-GUS proliferation marker or the DR5-GUS auxin-mediated growth marker, to diamagnetic levitation in the bore of a superconducting solenoid magnet. As a control, a second set of seedlings were exposed to a strong magnetic field, but not to levitation forces. A third set was exposed to a strong field and simulated hypergravity (2 g). Cell proliferation and cell growth cytological parameters were measured for each set of seedlings. Nucleolin immunodetection was used as a marker of cell growth. Collectively, the data indicate that these two fundamental cellular processes are decoupled in root meristems, as in microgravity: cell proliferation was enhanced whereas cell growth markers were depleted. These results also demonstrated delocalisation of auxin signalling in the root tip despite the fact that levitation of the seedling as a whole does not prevent the sedimentation of statoliths in the root cells. Conclusions In our model system, we found that diamagnetic levitation led to changes that are very similar to those caused by real- [e.g. on board the International Space Station (ISS)] or mechanically-simulated microgravity [e.g. using a Random Positioning Machine (RPM)]. These changes decoupled meristematic cell proliferation from ribosome biogenesis, and altered auxin polar transport. PMID:24006876

Detection of Phosphomonoester Signals in Proton-Decoupled 31P NMR Spectra of the Myocardium of Patients with Myocardial Hypertrophy

NASA Astrophysics Data System (ADS)

Jung, Wulf-Ingo; Sieverding, Ludger; Breuer, Johannes; Schmidt, Oliver; Widmaier, Stefan; Bunse, Michael; van Erckelens, Franz; Apitz, Jürgen; Dietze, Guenther J.; Lutz, Otto

1998-07-01

Proton-decoupled31P NMR spectroscopy at 1.5 T of the anterior left ventricular myocardium was used to monitor myocardial phosphate metabolism in asymptomatic patients with hypertrophic cardiomyopathy (HCM,n= 14) and aortic stenosis (AS,n= 12). In addition to the well-known phosphorus signals a phosphomonoester (PME) signal was detected at about 6.9 ppm in 7 HCM and 2 AS patients. This signal was not observed in the spectra of normal controls (n= 11). We suggest that in spectra of patients with myocardial hypertrophy the presence of a PME signal reflects alterations in myocardial glucose metabolism.

Reflectionless CMV Matrices and Scattering Theory

NASA Astrophysics Data System (ADS)

Chu, Sherry; Landon, Benjamin; Panangaden, Jane

2015-04-01

Reflectionless CMV matrices are studied using scattering theory. By changing a single Verblunsky coefficient, a full-line CMV matrix can be decoupled and written as the sum of two half-line operators. Explicit formulas for the scattering matrix associated to the coupled and decoupled operators are derived. In particular, it is shown that a CMV matrix is reflectionless iff the scattering matrix is off-diagonal which in turn provides a short proof of an important result of Breuer et al. (Commun Math Phys 295:531-550, 2010). These developments parallel those recently obtained for Jacobi matrices Jakšić et al. (Commun Math Phys 827-838, 2014).

A Novel Offset Cancellation Based on Parasitic-Insensitive Switched-Capacitor Sensing Circuit for the Out-of-Plane Single-Gimbaled Decoupled CMOS-MEMS Gyroscope

PubMed Central

Chang, Ming-Hui; Huang, Han-Pang

2013-01-01

This paper presents a novel parasitic-insensitive switched-capacitor (PISC) sensing circuit design in order to obtain high sensitivity and ultra linearity and reduce the parasitic effect for the out-of-plane single-gimbaled decoupled CMOS-MEMS gyroscope (SGDG). According to the simulation results, the proposed PISC circuit has better sensitivity and high linearity in a wide dynamic range. Experimental results also show a better performance. In addition, the PISC circuit can use signal processing to cancel the offset and noise. Thus, this circuit is very suitable for gyroscope measurement. PMID:23493122

Accurate quantification of fluorescent targets within turbid media based on a decoupled fluorescence Monte Carlo model.

PubMed

Deng, Yong; Luo, Zhaoyang; Jiang, Xu; Xie, Wenhao; Luo, Qingming

2015-07-01

We propose a method based on a decoupled fluorescence Monte Carlo model for constructing fluorescence Jacobians to enable accurate quantification of fluorescence targets within turbid media. The effectiveness of the proposed method is validated using two cylindrical phantoms enclosing fluorescent targets within homogeneous and heterogeneous background media. The results demonstrate that our method can recover relative concentrations of the fluorescent targets with higher accuracy than the perturbation fluorescence Monte Carlo method. This suggests that our method is suitable for quantitative fluorescence diffuse optical tomography, especially for in vivo imaging of fluorophore targets for diagnosis of different diseases and abnormalities.

Design of algorithms for a dispersive hyperbolic problem

NASA Technical Reports Server (NTRS)

Roe, Philip L.; Arora, Mohit

1991-01-01

In order to develop numerical schemes for stiff problems, a model of relaxing heat flow is studied. To isolate those errors unavoidably associated with discretization, a method of characteristics is developed, containing three free parameters depending on the stiffness ratio. It is shown that such 'decoupled' schemes do not take into account the interaction between the wave families, and hence result in incorrect wavespeeds. Schemes can differ by up to two orders of magnitude in their rms errors, even while maintaining second-order accuracy. 'Coupled' schemes which account for the interactions are developed to obtain two additional free parameters. Numerical results are given for several decoupled and coupled schemes.

Gravitational form factors and decoupling in 2D

NASA Astrophysics Data System (ADS)

Ribeiro, Tiago G.; Shapiro, Ilya L.; Zanusso, Omar

2018-07-01

We calculate and analyse non-local gravitational form factors induced by quantum matter fields in curved two-dimensional space. The calculations are performed for scalars, spinors and massive vectors by means of the covariant heat kernel method up to the second order in the curvature and confirmed using Feynman diagrams. The analysis of the ultraviolet (UV) limit reveals a generalized "running" form of the Polyakov action for a nonminimal scalar field and the usual Polyakov action in the conformally invariant cases. In the infrared (IR) we establish the gravitational decoupling theorem, which can be seen directly from the form factors or from the physical beta function for fields of any spin.

Stiffness modeling of compliant parallel mechanisms and applications in the performance analysis of a decoupled parallel compliant stage

NASA Astrophysics Data System (ADS)

Jiang, Yao; Li, Tie-Min; Wang, Li-Ping

2015-09-01

This paper investigates the stiffness modeling of compliant parallel mechanism (CPM) based on the matrix method. First, the general compliance matrix of a serial flexure chain is derived. The stiffness modeling of CPMs is next discussed in detail, considering the relative positions of the applied load and the selected displacement output point. The derived stiffness models have simple and explicit forms, and the input, output, and coupling stiffness matrices of the CPM can easily be obtained. The proposed analytical model is applied to the stiffness modeling and performance analysis of an XY parallel compliant stage with input and output decoupling characteristics. Then, the key geometrical parameters of the stage are optimized to obtain the minimum input decoupling degree. Finally, a prototype of the compliant stage is developed and its input axial stiffness, coupling characteristics, positioning resolution, and circular contouring performance are tested. The results demonstrate the excellent performance of the compliant stage and verify the effectiveness of the proposed theoretical model. The general stiffness models provided in this paper will be helpful for performance analysis, especially in determining coupling characteristics, and the structure optimization of the CPM.

Identifying geochemical processes using End Member Mixing Analysis to decouple chemical components for mixing ratio calculations

NASA Astrophysics Data System (ADS)

Pelizardi, Flavia; Bea, Sergio A.; Carrera, Jesús; Vives, Luis

2017-07-01

Mixing calculations (i.e., the calculation of the proportions in which end-members are mixed in a sample) are essential for hydrological research and water management. However, they typically require the use of conservative species, a condition that may be difficult to meet due to chemical reactions. Mixing calculation also require identifying end-member waters, which is usually achieved through End Member Mixing Analysis (EMMA). We present a methodology to help in the identification of both end-members and such reactions, so as to improve mixing ratio calculations. The proposed approach consists of: (1) identifying the potential chemical reactions with the help of EMMA; (2) defining decoupled conservative chemical components consistent with those reactions; (3) repeat EMMA with the decoupled (i.e., conservative) components, so as to identify end-members waters; and (4) computing mixing ratios using the new set of components and end-members. The approach is illustrated by application to two synthetic mixing examples involving mineral dissolution and cation exchange reactions. Results confirm that the methodology can be successfully used to identify geochemical processes affecting the mixtures, thus improving the accuracy of mixing ratios calculations and relaxing the need for conservative species.

Design and Fabrication of the NASA Decoupler Pylon for the F-16 Aircraft

NASA Technical Reports Server (NTRS)

Clayton, J. D.; Haller, R. L.; Hassler, J. M., Jr.

1985-01-01

The NASA Decoupler Pylon is a passive means of suppressing wing-store flutter. The feasibility of demonstrating this concept on the F-16 aircraft was established through model wind tunnel tests and analyses. As a result of these tests and studies a ship set of Decoupler Pylons was designed and fabricated for a flight test demonstration on the F-16 aircraft. Basic design criteria were developed during the analysis study pertaining to pylon pitch stiffness, alignment system requirements, and damping requirements. A design was developed which utilized an electrical motor for the pylon alignment system. The design uses a four pin, two link pivot design which results in a remote pivot located at the center of gravity of the store when the store is in the aligned position. The pitch spring was fabricated from a tapered constant stress cantilevered beam. The pylon has the same external lines as the existing production pylon and is designed to use a MAU-12 ejection rack which is the same as the one used with the production pylon. The detailed design and fabrication was supported with a complete ground test of the pylon prior to shipment to NASA.

The material footprint of nations

PubMed Central

Wiedmann, Thomas O.; Schandl, Heinz; Lenzen, Manfred; Moran, Daniel; Suh, Sangwon; West, James; Kanemoto, Keiichiro

2015-01-01

Metrics on resource productivity currently used by governments suggest that some developed countries have increased the use of natural resources at a slower rate than economic growth (relative decoupling) or have even managed to use fewer resources over time (absolute decoupling). Using the material footprint (MF), a consumption-based indicator of resource use, we find the contrary: Achievements in decoupling in advanced economies are smaller than reported or even nonexistent. We present a time series analysis of the MF of 186 countries and identify material flows associated with global production and consumption networks in unprecedented specificity. By calculating raw material equivalents of international trade, we demonstrate that countries’ use of nondomestic resources is, on average, about threefold larger than the physical quantity of traded goods. As wealth grows, countries tend to reduce their domestic portion of materials extraction through international trade, whereas the overall mass of material consumption generally increases. With every 10% increase in gross domestic product, the average national MF increases by 6%. Our findings call into question the sole use of current resource productivity indicators in policy making and suggest the necessity of an additional focus on consumption-based accounting for natural resource use. PMID:24003158

Impact of Cosmic-Ray Transport on Galactic Winds

NASA Astrophysics Data System (ADS)

Farber, R.; Ruszkowski, M.; Yang, H.-Y. K.; Zweibel, E. G.

2018-04-01

The role of cosmic rays generated by supernovae and young stars has very recently begun to receive significant attention in studies of galaxy formation and evolution due to the realization that cosmic rays can efficiently accelerate galactic winds. Microscopic cosmic-ray transport processes are fundamental for determining the efficiency of cosmic-ray wind driving. Previous studies modeled cosmic-ray transport either via a constant diffusion coefficient or via streaming proportional to the Alfvén speed. However, in predominantly cold, neutral gas, cosmic rays can propagate faster than in the ionized medium, and the effective transport can be substantially larger; i.e., cosmic rays can decouple from the gas. We perform three-dimensional magnetohydrodynamical simulations of patches of galactic disks including the effects of cosmic rays. Our simulations include the decoupling of cosmic rays in the cold, neutral interstellar medium. We find that, compared to the ordinary diffusive cosmic-ray transport case, accounting for the decoupling leads to significantly different wind properties, such as the gas density and temperature, significantly broader spatial distribution of cosmic rays, and higher wind speed. These results have implications for X-ray, γ-ray, and radio emission, and for the magnetization and pollution of the circumgalactic medium by cosmic rays.

Reusable Launch Vehicle Control In Multiple Time Scale Sliding Modes

NASA Technical Reports Server (NTRS)

Shtessel, Yuri; Hall, Charles; Jackson, Mark

2000-01-01

A reusable launch vehicle control problem during ascent is addressed via multiple-time scaled continuous sliding mode control. The proposed sliding mode controller utilizes a two-loop structure and provides robust, de-coupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of bounded external disturbances and plant uncertainties. Sliding mode control causes the angular rate and orientation angle tracking error dynamics to be constrained to linear, de-coupled, homogeneous, and vector valued differential equations with desired eigenvalues placement. Overall stability of a two-loop control system is addressed. An optimal control allocation algorithm is designed that allocates torque commands into end-effector deflection commands, which are executed by the actuators. The dual-time scale sliding mode controller was designed for the X-33 technology demonstration sub-orbital launch vehicle in the launch mode. Simulation results show that the designed controller provides robust, accurate, de-coupled tracking of the orientation angle command profiles in presence of external disturbances and vehicle inertia uncertainties. This is a significant advancement in performance over that achieved with linear, gain scheduled control systems currently being used for launch vehicles.

Quantum sensing of weak radio-frequency signals by pulsed Mollow absorption spectroscopy.

PubMed

Joas, T; Waeber, A M; Braunbeck, G; Reinhard, F

2017-10-17

Quantum sensors-qubits sensitive to external fields-have become powerful detectors for various small acoustic and electromagnetic fields. A major key to their success have been dynamical decoupling protocols which enhance sensitivity to weak oscillating (AC) signals. Currently, those methods are limited to signal frequencies below a few MHz. Here we harness a quantum-optical effect, the Mollow triplet splitting of a strongly driven two-level system, to overcome this limitation. We microscopically understand this effect as a pulsed dynamical decoupling protocol and find that it enables sensitive detection of fields close to the driven transition. Employing a nitrogen-vacancy center, we detect GHz microwave fields with a signal strength (Rabi frequency) below the current detection limit, which is set by the center's spectral linewidth [Formula: see text]. Pushing detection sensitivity to the much lower 1/T 2 limit, this scheme could enable various applications, most prominently coherent coupling to single phonons and microwave photons.Dynamical decoupling protocols can enhance the sensitivity of quantum sensors but this is limited to signal frequencies below a few MHz. Here, Joas et al. use the Mollow triplet splitting in a nitrogen-vacancy centre to overcome this limitation, enabling sensitive detection of signals in the GHz range.

The material footprint of nations.

PubMed

Wiedmann, Thomas O; Schandl, Heinz; Lenzen, Manfred; Moran, Daniel; Suh, Sangwon; West, James; Kanemoto, Keiichiro

2015-05-19

Metrics on resource productivity currently used by governments suggest that some developed countries have increased the use of natural resources at a slower rate than economic growth (relative decoupling) or have even managed to use fewer resources over time (absolute decoupling). Using the material footprint (MF), a consumption-based indicator of resource use, we find the contrary: Achievements in decoupling in advanced economies are smaller than reported or even nonexistent. We present a time series analysis of the MF of 186 countries and identify material flows associated with global production and consumption networks in unprecedented specificity. By calculating raw material equivalents of international trade, we demonstrate that countries' use of nondomestic resources is, on average, about threefold larger than the physical quantity of traded goods. As wealth grows, countries tend to reduce their domestic portion of materials extraction through international trade, whereas the overall mass of material consumption generally increases. With every 10% increase in gross domestic product, the average national MF increases by 6%. Our findings call into question the sole use of current resource productivity indicators in policy making and suggest the necessity of an additional focus on consumption-based accounting for natural resource use.

"Cooking the sample": radiofrequency induced heating during solid-state NMR experiments.

PubMed

d'Espinose de Lacaillerie, Jean-Baptiste; Jarry, Benjamin; Pascui, Ovidiu; Reichert, Detlef

2005-09-01

Dissipation of radiofrequency (RF) energy as heat during continuous wave decoupling in solid-state NMR experiment was examined outside the conventional realm of such phenomena. A significant temperature increase could occur while performing dynamic NMR measurements provided the sample contains polar molecules and the sequence calls for relatively long applications of RF power. It was shown that the methyl flip motion in dimethylsulfone (DMS) is activated by the decoupling RF energy conversion to heat during a CODEX pulse sequence. This introduced a significant bias in the correlation time-temperature dependency measurement used to obtain the activation energy of the motion. By investigating the dependency of the temperature increase in hydrated lead nitrate on experimental parameters during high-power decoupling one-pulse experiments, the mechanisms for the RF energy deposition was identified. The samples were heated due to dissipation of the energy absorbed by dielectric losses, a phenomenon commonly known as "microwave" heating. It was thus established that during solid-state NMR experiments at moderate B0 fields, RF heating could lead to the heating of samples containing polar molecules such as hydrated polymers and inorganic solids. In particular, this could result in systematic errors for slow dynamics measurements by solid-state NMR.

Phenomenological study of decoherence in solid-state spin qubits due to nuclear spin diffusion

NASA Astrophysics Data System (ADS)

Biercuk, Michael J.; Bluhm, Hendrik

2011-06-01

We present a study of the prospects for coherence preservation in solid-state spin qubits using dynamical decoupling protocols. Recent experiments have provided the first demonstrations of multipulse dynamical decoupling sequences in this qubit system, but quantitative analyses of potential coherence improvements have been hampered by a lack of concrete knowledge of the relevant noise processes. We present calculations of qubit coherence under the application of arbitrary dynamical decoupling pulse sequences based on an experimentally validated semiclassical model. This phenomenological approach bundles the details of underlying noise processes into a single experimentally relevant noise power spectral density. Our results show that the dominant features of experimental measurements in a two-electron singlet-triplet spin qubit can be replicated using a 1/ω2 noise power spectrum associated with nuclear spin flips in the host material. Beginning with this validation, we address the effects of nuclear programming, high-frequency nuclear spin dynamics, and other high-frequency classical noise sources, with conjectures supported by physical arguments and microscopic calculations where relevant. Our results provide expected performance bounds and identify diagnostic metrics that can be measured experimentally in order to better elucidate the underlying nuclear spin dynamics.

Temperature-driven decoupling of key phases of organic matter degradation in marine sediments.

PubMed

Weston, Nathaniel B; Joye, Samantha B

2005-11-22

The long-term burial of organic carbon in sediments results in the net accumulation of oxygen in the atmosphere, thereby mediating the redox state of the Earth's biosphere and atmosphere. Sediment microbial activity plays a major role in determining whether particulate organic carbon is recycled or buried. A diverse consortium of microorganisms that hydrolyze, ferment, and terminally oxidize organic compounds mediates anaerobic organic matter mineralization in anoxic sediments. Variable temperature regulation of the sequential processes, leading from the breakdown of complex particulate organic carbon to the production and subsequent consumption of labile, low-molecular weight, dissolved intermediates, could play a key role in controlling rates of overall organic carbon mineralization. We examined sediment organic carbon cycling in a sediment slurry and in flow through bioreactor experiments. The data show a variable temperature response of the microbial functional groups mediating organic matter mineralization in anoxic marine sediments, resulting in the temperature-driven decoupling of the production and consumption of organic intermediates. This temperature-driven decoupling leads to the accumulation of labile, low-molecular weight, dissolved organic carbon at low temperatures and low-molecular weight dissolved organic carbon limitation of terminal metabolism at higher temperatures.

Larval traits show temporally consistent constraints, but are decoupled from post-settlement juvenile growth, in an intertidal fish.

PubMed

Thia, Joshua A; Riginos, Cynthia; Liggins, Libby; Figueira, Will F; McGuigan, Katrina

2018-05-05

1.Complex life-cycles may evolve to dissociate distinct developmental phases in an organism's lifetime. However, genetic or environmental factors may restrict trait independence across life stages, constraining ontogenetic trajectories. Quantifying covariance across life-stages and their temporal variability is fundamental in understanding life-history phenotypes and potential distributions and consequences for selection. 2.We studied developmental constraints in an intertidal fish (Bathygobius cocosensis: Gobiidae) with a discrete pelagic larval phase and benthic juvenile phase. We tested whether traits occurring earlier in life affected those expressed later, and whether larval traits were decoupled from post-settlement juvenile traits. Sampling distinct cohorts from three annual breeding seasons afforded tests of temporally variability in trait covariance. 3.From otoliths (fish ear stones), we measured hatch size, larval duration, pelagic growth (larval traits) and early post-settlement growth (juvenile trait) in 124 juvenile B. cocoensis. We used path analyses to model trait relationships with respect to their chronological expression, comparing models among seasons. We also modelled the effect of season and hatch date on each individual trait to quantify their inherent variability. 4.Our path analyses demonstrated a decoupling of larval traits on juvenile growth. Within the larval phase, longer larval durations resulted in greater pelagic growth, and larger size-at-settlement. There was also evidence that larger hatch size might reduce larval durations, but this effect was only marginally significant. Although pelagic and post-settlement growth were decoupled, pelagic growth had post-settlement consequences: individuals with high pelagic growth were among the largest fish at settlement, and remained among the largest early post-settlement. We observed no evidence that trait relationships varied among breeding seasons, but larval duration differed among breeding seasons, and was shorter for larvae hatching later within each season. 5.Overall, we demonstrate mixed support for the expectation that traits in different life-stages are independent. While post-settlement growth was decoupled from larval traits, pelagic development had consequences for the size of newly settled juveniles. Temporal consistency in trait covariances implies that genetic and/or environmental factors influencing them were stable over our three-year study. Our work highlights the importance of individual developmental experiences and temporal variability in understanding population distributions of life-history traits. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Indirectly detected chemical shift correlation NMR spectroscopy in solids under fast magic angle spinning

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

Mao, Kanmi

The development of fast magic angle spinning (MAS) opened up an opportunity for the indirect detection of insensitive low-γ nuclei (e.g., 13C and 15N) via the sensitive high-{gamma} nuclei (e.g., 1H and 19F) in solid-state NMR, with advanced sensitivity and resolution. In this thesis, new methodology utilizing fast MAS is presented, including through-bond indirectly detected heteronuclear correlation (HETCOR) spectroscopy, which is assisted by multiple RF pulse sequences for 1H- 1H homonuclear decoupling. Also presented is a simple new strategy for optimization of 1H- 1H homonuclear decoupling. As applications, various classes of materials, such as catalytic nanoscale materials, biomolecules, and organic complexes, are studied by combining indirect detection and other one-dimensional (1D) and two-dimensional (2D) NMR techniques. Indirectly detected through-bond HETCOR spectroscopy utilizing refocused INEPT (INEPTR) mixing was developed under fast MAS (Chapter 2). The time performance of this approach in 1H detected 2D 1H{l_brace} 13C{r_brace} spectra was significantly improved, by a factor of almost 10, compared to the traditional 13C detected experiments, as demonstrated by measuring naturally abundant organic-inorganic mesoporous hybrid materials. The through-bond scheme was demonstrated as a new analytical tool, which provides complementary structural information in solid-state systems in addition to through-space correlation. To further benefit the sensitivity of the INEPT transfer in rigid solids, the combined rotation and multiple-pulse spectroscopy (CRAMPS) was implemented for homonuclear 1H decoupling under fast MAS (Chapter 3). Several decoupling schemes (PMLG5 m more » $$\\bar{x}$$, PMLG5 mm $$\\bar{x}$$x and SAM3) were analyzed to maximize the performance of through-bond transfer based on decoupling efficiency as well as scaling factors. Indirect detection with assistance of PMLG m $$\\bar{x}$$ during INEPTR transfer proved to offer the highest sensitivity gains of 3-10. In addition, the CRAMPS sequence was applied under fast MAS to increase the 1H resolution during t 1 evolution in the traditional, 13C detected HETCOR scheme. Two naturally abundant solids, tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (f-MLF-OH) and brown coal, with well ordered and highly disordered structures, respectively, are studied to confirm the capabilities of these techniques. Concomitantly, a simple optimization of 1H homonuclear dipolar decoupling at MAS rates exceeding 10 kHz was developed (Chapter 4). The fine-tuned decoupling efficiency can be obtained by minimizing the signal loss due to transverse relaxation in a simple spin-echo experiment, using directly the sample of interest. The excellent agreement between observed decoupling pattern and earlier theoretical predictions confirmed the utility of this strategy. The properties of naturally abundant surface-bound fluorocarbon groups in mesoporous silica nanoparticles (MSNs) were investigated by the above-mentioned multidimensional solid-state NMR experiments and theoretical modeling (Chapter 5). Two conformations of (pentafluorophenyl)propyl groups (abbreviated as PFP) were determined as PFP-prone and PFP-upright, whose aromatic rings are located above the siloxane bridges and in roughly upright position, respectively. Several 1D and 2D NMR techniques were implemented in the characterizations, including indirectly detected 1H{l_brace} 13C{r_brace} and 19F{l_brace} 13C{r_brace} 2D HETCOR, Carr-Purcell-Meiboom-Gill (CPMG) assisted 29Si direct polarization and 29Si 19F 2D experiments, 2D double-quantum (DQ) 19F MAS NMR spectra and spin-echo measurements. Furthermore, conformational details of two types of PFP were confirmed by theoretical calculation, operated by Dr. Takeshi Kobayashi. Finally, the arrangement of two surfactants, cetyltrimetylammoium bromide (CTAB) and cetylpyridinium bromide (CPB), mixed inside the MSN pores, was studied by solid-state NMR (Chapter 6). By analyzing the 1H- 1H DQMAS and NOESY correlation spectra, the CTAB and CPB molecules were shown to co-exist inside the pores without forming significant monocomponent domains. A 'folded-over' conformation of CPB headgroups was proposed according to the results from 1H- 29Si 2D HETCOR.« less

Study on initiative vibration absorbing technology of optics in strong disturbed environment

NASA Astrophysics Data System (ADS)

Jia, Si-nan; Xiong, Mu-di; Zou, Xiao-jie

2007-12-01

Strong disturbed environment is apt to cause irregular vibration, which seriously affects optical collimation. To improve the performance of laser beam, three-point dynamic vibration absorbing method is proposed, and laser beam initiative vibration absorbing system is designed. The maladjustment signal is detected by position sensitive device (PSD), three groups of PZT are driven to adjust optical element in real-time, so the performance of output-beam is improved. The coupling model of the system is presented. Multivariable adaptive closed-loop decoupling arithmetic is used to design three-input-three-output decoupling controller, so that high precision dynamic adjusting is realized. Experiments indicate that the system has good shock absorbing efficiency.

Choice of phase in the CS and IOS approximation

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

Snider, R.F.

1982-04-01

With the recognition that the angular momentum representations of unit position and momentum directional states must have different but uniquely related phases, the previously presented expression of scattering amplitude in terms of IOS angle dependent phase shifts must be modified. This resolves a major disagreement between IOS and close coupled degeneracy averaged differential cross sections. It is found that the phase factors appearing in the differential cross section have nothing to do with any particular choice of decoupling parameter. As a consequence, the differential cross section is relatively insensitive to the choice of CS decoupling parameter. The phase relations obtainedmore » are also in agreement with those deduced from the Born approximation.« less

A random access memory immune to single event upset using a T-Resistor

DOEpatents

Ochoa, A. Jr.

1987-10-28

In a random access memory cell, a resistance ''T'' decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell. 4 figs.

Generalization of Wilemski-Fixman-Weiss decoupling approximation to the case involving multiple sinks of different sizes, shapes, and reactivities.

PubMed

Uhm, Jesik; Lee, Jinuk; Eun, Changsun; Lee, Sangyoub

2006-08-07

We generalize the Wilemski-Fixman-Weiss decoupling approximation to calculate the transient rate of absorption of point particles into multiple sinks of different sizes, shapes, and reactivities. As an application we consider the case involving two spherical sinks. We obtain a Laplace-transform expression for the transient rate that is in excellent agreement with computer simulations. The long-time steady-state rate has a relatively simple expression, which clearly shows the dependence on the diffusion constant of the particles and on the sizes and reactivities of sinks, and its numerical result is in good agreement with the known exact result that is given in terms of recursion relations.

Calculational Schemes in GUTs

NASA Astrophysics Data System (ADS)

Kounnas, Costas

The following sections are included: * Introduction * Mass Spectrum in a Spontaneously Broken-Theory SU(5) - Minimal Model * Renormalization and Renormalization Group Equation (R.G.E.) * Step Approximation and Decoupling Theorem * Notion of the Effective Coupling Constant * First Estimation of MX, α(MX) and sin2θ(MW) * Renormalization Properties and Photon-Z Mixing * β-Function Definitions * Threshold Functions and Decoupling Theorem * MX-Determination * Proton Lifetime * sin2θ(μ)-Determination * Quark-Lepton Mass Relations (mb/mτ) * Overview of the Conventional GUTs - Hierarchy Problem * Stability of Hierarchy - Supersymmetric GUTS * Cosmologically Acceptable SUSY GUT Models * Radiative Breaking of SU(2) × U(1) — MW/MX Hierarchy Generation * No Scale Supergravity Models^{56,57} Dynamical Determination of M_{B}-M_{F} * Conclusion * References

Directly and indirectly detected through-bond heteronuclear correlation solid-state NMR spectroscopy under fast MAS

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

Mao, Kanmi; Pruski, Marek

Two-dimensional through-bond {sup 1}H({sup 13}C) solid-state NMR experiments utilizing fast magic angle spinning (MAS) and homonuclear multipulse {sup 1}H decoupling are presented. Remarkable efficiency of polarization transfer can be achieved at MAS rates exceeding 40 kHz, which is instrumental in these measurements. Schemes utilizing direct and indirect detection of heteronuclei are compared in terms of resolution and sensitivity. A simple procedure for optimization of {sup 1}H homonuclear decoupling sequences under these conditions is proposed. The capabilities of these techniques were confirmed on two naturally abundant solids, tripeptide N-formyl-l-methionyl-l-leucyl-l-phenylalanine (f-MLF-OH) and brown coal.

Directly and indirectly detected through-bond heteronuclear correlation solid-state NMR spectroscopy under fast MAS

NASA Astrophysics Data System (ADS)

Mao, Kanmi; Pruski, Marek

2009-12-01

Two-dimensional through-bond 1H{ 13C} solid-state NMR experiments utilizing fast magic angle spinning (MAS) and homonuclear multipulse 1H decoupling are presented. Remarkable efficiency of polarization transfer can be achieved at MAS rates exceeding 40 kHz, which is instrumental in these measurements. Schemes utilizing direct and indirect detection of heteronuclei are compared in terms of resolution and sensitivity. A simple procedure for optimization of 1H homonuclear decoupling sequences under these conditions is proposed. The capabilities of these techniques were confirmed on two naturally abundant solids, tripeptide N- formyl- L-methionyl- L-leucyl- L-phenylalanine (f-MLF-OH) and brown coal.

Decoupling correction system in RHIC

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

Trbojevic, D.; Tepikian, S.; Peggs, S.

A global linear decoupling in the Relativistic Heavy Ion Collider (RHIC) is going to be performed with the three families of skew quadrupoles. The operating horizontal and vertical betatron tunes in the RHIC will be separated by one unit [nu][sub x]=28.19 and [nu][sub y]=29.18. The linear coupling is corrected by minimizing the tune splitting [Delta][nu]-the off diagonal matrix [bold m] (defined by Edwards and Teng). The skew quadrupole correction system is located close to each of the six interaction regions. A detail study of the system is presented by the use of the TEAPOT accelerator physics code. [copyright] 1994 Americanmore » Institute of Physics« less

Environmental noise spectroscopy with qubits subjected to dynamical decoupling

NASA Astrophysics Data System (ADS)

Szańkowski, P.; Ramon, G.; Krzywda, J.; Kwiatkowski, D.; Cywiński, Ł.

2017-08-01

A qubit subjected to pure dephasing due to classical Gaussian noise can be turned into a spectrometer of this noise by utilizing its readout under properly chosen dynamical decoupling (DD) sequences to reconstruct the power spectral density of the noise. We review the theory behind this DD-based noise spectroscopy technique, paying special attention to issues that arise when the environmental noise is non-Gaussian and/or it has truly quantum properties. While we focus on the theoretical basis of the method, we connect the discussed concepts with specific experiments, and provide an overview of environmental noise models relevant for solid-state based qubits, including quantum-dot based spin qubits, superconducting qubits, and NV centers in diamond.

Random access memory immune to single event upset using a T-resistor

DOEpatents

Ochoa, Jr., Agustin

1989-01-01

In a random access memory cell, a resistance "T" decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell.

Protecting a quantum memory for a photonic polarization qubit in a cold atomic ensemble by dynamical decoupling.

PubMed

Wu, Yuelong; Chen, Lirong; Xu, Zhongxiao; Wang, Hai

2014-09-22

We report an experimental demonstration of storage of photonic polarization qubit (PPQ) protected by dynamical decoupling (DD). PPQ's states are stored as a superposition of two spin waves by electromagnetically-induced-transparency (EIT). Carr-Purcell-Meiboom-Gill (CPMG) DD sequences are applied to the spin-wave superposition to suppress its decoherence. Thus, the quantum process fidelity remains better than 0.8 for up to 800 μs storage time, which is 3.4-times longer than the corresponding storage time of ~180 μs without the CPMG sequences. This work is a key step towards the storage of single-photon polarization qubit protected by the CPMG sequences.

Cross-modal decoupling in temporal attention.

PubMed

Mühlberg, Stefanie; Oriolo, Giovanni; Soto-Faraco, Salvador

2014-06-01

Prior studies have repeatedly reported behavioural benefits to events occurring at attended, compared to unattended, points in time. It has been suggested that, as for spatial orienting, temporal orienting of attention spreads across sensory modalities in a synergistic fashion. However, the consequences of cross-modal temporal orienting of attention remain poorly understood. One challenge is that the passage of time leads to an increase in event predictability throughout a trial, thus making it difficult to interpret possible effects (or lack thereof). Here we used a design that avoids complete temporal predictability to investigate whether attending to a sensory modality (vision or touch) at a point in time confers beneficial access to events in the other, non-attended, sensory modality (touch or vision, respectively). In contrast to previous studies and to what happens with spatial attention, we found that events in one (unattended) modality do not automatically benefit from happening at the time point when another modality is expected. Instead, it seems that attention can be deployed in time with relative independence for different sensory modalities. Based on these findings, we argue that temporal orienting of attention can be cross-modally decoupled in order to flexibly react according to the environmental demands, and that the efficiency of this selective decoupling unfolds in time. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Atrioventricular nonuniformity of pericardial constraint.

PubMed

Hamilton, Douglas R; Sas, Rozsa; Tyberg, John V

2004-10-01

Physiologists and clinicians commonly refer to "pressure" as a measure of the constraining effects of the pericardium; however, "pericardial pressure" is really a local measurement of epicardial radial stress. During diastole, from the bottom of the y descent to the beginning of the a wave, pericardial pressure over the right atrium (P(pRA)) is approximately equal to that over the right ventricle (P(pRV)). However, in systole, during the interval between the bottom of the x descent and the peak of the v wave, these two pericardial pressures appear to be completely decoupled in that P(pRV) decreases, whereas P(pRA) remains constant or increases. This decoupling indicates considerable mechanical independence between the RA and RV during systole. That is, RV systolic emptying lowers P(pRV), but P(pRA) continues to increase, suggesting that the relation of the pericardium to the RA must allow effective constraint, even though the pericardium over the RV is simultaneously slack. In conclusion, we measured the pericardial pressure responsible for the previously reported nonuniformity of pericardial strain. P(pRA) and P(pRV) are closely coupled during diastole, but during systole they become decoupled. Systolic nonuniformity of pericardial constraint may augment the atrioventricular valve-opening pressure gradient in early diastole and, so, affect ventricular filling.

Marine boundary layer structure as observed by A-train satellites

DOE PAGES

Luo, Tao; Wang, Zhien; Zhang, Damao; ...

2016-05-13

The marine boundary layer (MBL) structure is important to the marine low cloud processes, and the exchange of heat, momentum, and moisture between oceans and the low atmosphere. This study examines the MBL structure over the eastern Pacific region and further explores the controlling factors of MBL structure over the global oceans with a new 4-year satellite-based data set. The MBL top (boundary layer height, BLH) and the mixing layer height (MLH) were identified using the MBL aerosol lidar backscattering from the CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations). Results showed that the MBL is generally decoupled with MLH ∕ BLHmore » ratio ranging from  ∼  0.5 to  ∼  0.8 over the eastern Pacific Ocean region. The MBL decoupling magnitude is mainly controlled by estimated inversion strength (EIS), which in turn controls the cloud top entrainment process. The systematic differences between drizzling and non-drizzling stratocumulus tops also show dependence on EIS. This may be related to the meso-scale circulations or gravity wave in the MBL. Further analysis indicates that the MBL shows a similar decoupled structure for clear-sky and cumulus-cloud-topped conditions, but is better mixed under stratiform cloud breakup and overcast conditions.« less

Decoupling the structure from the ground motion during earthquakes by employing friction pendulums

NASA Astrophysics Data System (ADS)

Gillich, G. R.; Iancu, V.; Gillich, N.; Korka, Z. I.; Chioncel, C. P.; Hatiegan, C.

2018-01-01

Avoiding dynamic loads on structures during earthquakes is an actual issue since seismic actions can harm or destroy the built environment. Several attempts to prevent this are possible, the essence being to decouple the structure from the ground motion during earthquakes and preventing in this way large deflections and high accelerations. A common approach is the use of friction pendulums, with cylindrical or spherical surfaces but not limited to that, inserted between the ground and the structure, respectively between the pillar and the superstructure. This type of bearings permits small pendulum motion and in this way, earthquake-induced displacements that occur in the bearings are not integrally transmitted to the structure. The consequence is that the structure is subject to greatly reduced lateral loads and shaking movements. In the experiments, conducted to prove the efficiency of the friction pendulums, we made use of an own designed and manufactured shaking table. Two types of sliding surfaces are analyzed, one polynomial of second order (i.e. circular) and one of a superior order. For both pendulum types, analytical models were developed. The results have shown that the structure is really decoupled from the ground motion and has a similar behaviour as that described by the analytic model.

Decoupling of soil carbon and nitrogen turnover partly explains increased net ecosystem production in response to nitrogen fertilization

NASA Astrophysics Data System (ADS)

Ehtesham, Emad; Bengtson, Per

2017-04-01

During the last decade there has been an ongoing controversy regarding the extent to which nitrogen fertilization can increase carbon sequestration and net ecosystem production in forest ecosystems. The debate is complicated by the fact that increased nitrogen availability caused by nitrogen deposition has coincided with increasing atmospheric carbon dioxide concentrations. The latter could further stimulate primary production but also result in increased allocation of carbon to root exudates, which could potentially ‘prime’ the decomposition of soil organic matter. Here we show that increased input of labile carbon to forest soil caused a decoupling of soil carbon and nitrogen cycling, which was manifested as a reduction in respiration of soil organic matter that coincided with a substantial increase in gross nitrogen mineralization. An estimate of the magnitude of the effect demonstrates that the decoupling could potentially result in an increase in net ecosystem production by up to 51 kg C ha-1 day-1 in nitrogen fertilized stands during peak summer. Even if the effect is several times lower on an annual basis, the results still suggest that nitrogen fertilization can have a much stronger influence on net ecosystem production than can be expected from a direct stimulation of primary production alone.

A piloted evaluation of an oblique-wing research aircraft motion simulation with decoupling control laws

NASA Technical Reports Server (NTRS)

Kempel, Robert W.; Mcneill, Walter E.; Gilyard, Glenn B.; Maine, Trindel A.

1988-01-01

The NASA Ames Research Center developed an oblique-wing research plane from NASA's digital fly-by-wire airplane. Oblique-wing airplanes show large cross-coupling in control and dynamic behavior which is not present on conventional symmetric airplanes and must be compensated for to obtain acceptable handling qualities. The large vertical motion simulator at NASA Ames-Moffett was used in the piloted evaluation of a proposed flight control system designed to provide decoupled handling qualities. Five discrete flight conditions were evaluated ranging from low altitude subsonic Mach numbers to moderate altitude supersonic Mach numbers. The flight control system was effective in generally decoupling the airplane. However, all participating pilots objected to the high levels of lateral acceleration encountered in pitch maneuvers. In addition, the pilots were more critical of left turns (in the direction of the trailing wingtip when skewed) than they were of right turns due to the tendency to be rolled into the left turns and out of the right turns. Asymmetric side force as a function of angle of attack was the primary cause of lateral acceleration in pitch. Along with the lateral acceleration in pitch, variation of rolling and yawing moments as functions of angle of attack caused the tendency to roll into left turns and out of right turns.

Protecting unknown two-qubit entangled states by nesting Uhrig's dynamical decoupling sequences

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

Mukhtar, Musawwadah; Soh, Wee Tee; Saw, Thuan Beng

2010-11-15

Future quantum technologies rely heavily on good protection of quantum entanglement against environment-induced decoherence. A recent study showed that an extension of Uhrig's dynamical decoupling (UDD) sequence can (in theory) lock an arbitrary but known two-qubit entangled state to the Nth order using a sequence of N control pulses [Mukhtar et al., Phys. Rev. A 81, 012331 (2010)]. By nesting three layers of explicitly constructed UDD sequences, here we first consider the protection of unknown two-qubit states as superposition of two known basis states, without making assumptions of the system-environment coupling. It is found that the obtained decoherence suppression canmore » be highly sensitive to the ordering of the three UDD layers and can be remarkably effective with the correct ordering. The detailed theoretical results are useful for general understanding of the nature of controlled quantum dynamics under nested UDD. As an extension of our three-layer UDD, it is finally pointed out that a completely unknown two-qubit state can be protected by nesting four layers of UDD sequences. This work indicates that when UDD is applicable (e.g., when the environment has a sharp frequency cutoff and when control pulses can be taken as instantaneous pulses), dynamical decoupling using nested UDD sequences is a powerful approach for entanglement protection.« less

The dynamics and control of large flexible space structures, 2. Part A: Shape and orientation control using point actuators

NASA Technical Reports Server (NTRS)

Bainum, P. M.; Reddy, A. S. S. R.

1979-01-01

The equations of planar motion for a flexible beam in orbit which includes the effects of gravity gradient torques and control torques from point actuators located along the beam was developed. Two classes of theorems are applied to the linearized form of these equations to establish necessary conditions for controlability for preselected actuator configurations. The feedback gains are selected: (1) based on the decoupling of the original coordinates and to obtain proper damping, and (2) by applying the linear regulator problem to the individual model coordinates separately. The linear control laws obtained using both techniques were evaluated by numerical integration of the nonlinear system equations. Numerical examples considering pitch and various number of modes with different combination of actuator numbers and locations are presented. The independent model control concept used earlier with a discretized model of the thin beam in orbit was reviewed for the case where the number of actuators is less than the number of modes. Results indicate that although the system is controllable it is not stable about the nominal (local vertical) orientation when the control is based on modal decoupling. An alternate control law not based on modal decoupling ensures stability of all the modes.

HUBBLE SPACE TELESCOPE AND HI IMAGING OF STRONG RAM PRESSURE STRIPPING IN THE COMA SPIRAL NGC 4921: DENSE CLOUD DECOUPLING AND EVIDENCE FOR MAGNETIC BINDING IN THE ISM

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

Kenney, Jeffrey D. P.; Abramson, Anne; Bravo-Alfaro, Hector, E-mail: jeff.kenney@yale.edu

Remarkable dust extinction features in the deep Hubble Space Telescope (HST) V and I images of the face-on Coma cluster spiral galaxy NGC 4921 show in unprecedented ways how ram pressure strips the ISM from the disk of a spiral galaxy. New VLA HI maps show a truncated and highly asymmetric HI disk with a compressed HI distribution in the NW, providing evidence for ram pressure acting from the NW. Where the HI distribution is truncated in the NW region, HST images show a well-defined, continuous front of dust that extends over 90° and 20 kpc. This dust front separatesmore » the dusty from dust-free regions of the galaxy, and we interpret it as galaxy ISM swept up near the leading side of the ICM–ISM interaction. We identify and characterize 100 pc–1 kpc scale substructure within this dust front caused by ram pressure, including head–tail filaments, C-shaped filaments, and long smooth dust fronts. The morphology of these features strongly suggests that dense gas clouds partially decouple from surrounding lower density gas during stripping, but decoupling is inhibited, possibly by magnetic fields that link and bind distant parts of the ISM.« less

Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization

PubMed Central

Hoff, Daniel E.M.; Albert, Brice J.; Saliba, Edward P.; Scott, Faith J.; Choi, Eric J.; Mardini, Michael; Barnes, Alexander B.

2015-01-01

Hyperfine decoupling and pulsed dynamic nuclear polarization (DNP) are promising techniques to improve high field DNP NMR. We explore experimental and theoretical considerations to implement them with magic angle spinning (MAS). Microwave field simulations using the high frequency structural simulator (HFSS) software suite are performed to characterize the inhomogeneous phase independent microwave field throughout a 198 GHz MAS DNP probe. Our calculations show that a microwave power input of 17 W is required to generate an average EPR nutation frequency of 0.84 MHz. We also present a detailed calculation of microwave heating from the HFSS parameters and find that 7.1% of the incident microwave power contributes to dielectric sample heating. Voltage tunable gyrotron oscillators are proposed as a class of frequency agile microwave sources to generate microwave frequency sweeps required for the frequency modulated cross effect, electron spin inversions, and hyperfine decoupling. Electron spin inversions of stable organic radicals are simulated with SPINEVOLUTION using the inhomogeneous microwave fields calculated by HFSS. We calculate an electron spin inversion efficiency of 56% at a spinning frequency of 5 kHz. Finally, we demonstrate gyrotron acceleration potentials required to generate swept microwave frequency profiles for the frequency modulated cross effect and electron spin inversions. PMID:26482131

Surgical model-view-controller simulation software framework for local and collaborative applications

PubMed Central

Sankaranarayanan, Ganesh; Halic, Tansel; Arikatla, Venkata Sreekanth; Lu, Zhonghua; De, Suvranu

2010-01-01

Purpose Surgical simulations require haptic interactions and collaboration in a shared virtual environment. A software framework for decoupled surgical simulation based on a multi-controller and multi-viewer model-view-controller (MVC) pattern was developed and tested. Methods A software framework for multimodal virtual environments was designed, supporting both visual interactions and haptic feedback while providing developers with an integration tool for heterogeneous architectures maintaining high performance, simplicity of implementation, and straightforward extension. The framework uses decoupled simulation with updates of over 1,000 Hz for haptics and accommodates networked simulation with delays of over 1,000 ms without performance penalty. Results The simulation software framework was implemented and was used to support the design of virtual reality-based surgery simulation systems. The framework supports the high level of complexity of such applications and the fast response required for interaction with haptics. The efficacy of the framework was tested by implementation of a minimally invasive surgery simulator. Conclusion A decoupled simulation approach can be implemented as a framework to handle simultaneous processes of the system at the various frame rates each process requires. The framework was successfully used to develop collaborative virtual environments (VEs) involving geographically distributed users connected through a network, with the results comparable to VEs for local users. PMID:20714933

Surgical model-view-controller simulation software framework for local and collaborative applications.

PubMed

Maciel, Anderson; Sankaranarayanan, Ganesh; Halic, Tansel; Arikatla, Venkata Sreekanth; Lu, Zhonghua; De, Suvranu

2011-07-01

Surgical simulations require haptic interactions and collaboration in a shared virtual environment. A software framework for decoupled surgical simulation based on a multi-controller and multi-viewer model-view-controller (MVC) pattern was developed and tested. A software framework for multimodal virtual environments was designed, supporting both visual interactions and haptic feedback while providing developers with an integration tool for heterogeneous architectures maintaining high performance, simplicity of implementation, and straightforward extension. The framework uses decoupled simulation with updates of over 1,000 Hz for haptics and accommodates networked simulation with delays of over 1,000 ms without performance penalty. The simulation software framework was implemented and was used to support the design of virtual reality-based surgery simulation systems. The framework supports the high level of complexity of such applications and the fast response required for interaction with haptics. The efficacy of the framework was tested by implementation of a minimally invasive surgery simulator. A decoupled simulation approach can be implemented as a framework to handle simultaneous processes of the system at the various frame rates each process requires. The framework was successfully used to develop collaborative virtual environments (VEs) involving geographically distributed users connected through a network, with the results comparable to VEs for local users.

Rayleigh-wave dispersion reveals crust-mantle decoupling beneath eastern Tibet.

PubMed

Legendre, Cédric P; Deschamps, Frédéric; Zhao, Li; Chen, Qi-Fu

2015-11-09

The Tibetan Plateau results from the collision of the Indian and Eurasian Plates during the Cenozoic, which produced at least 2,000 km of convergence. Its tectonics is dominated by an eastward extrusion of crustal material that has been explained by models implying either a mechanical decoupling between the crust and the lithosphere, or lithospheric deformation. Discriminating between these end-member models requires constraints on crustal and lithospheric mantle deformations. Distribution of seismic anisotropy may be inferred from the mapping of azimuthal anisotropy of surface waves. Here, we use data from the CNSN to map Rayleigh-wave azimuthal anisotropy in the crust and lithospheric mantle beneath eastern Tibet. Beneath Tibet, the anisotropic patterns at periods sampling the crust support an eastward flow up to 100°E in longitude, and a southward bend between 100°E and 104°E. At longer periods, sampling the lithospheric mantle, the anisotropic structures are consistent with the absolute plate motion. By contrast, in the Sino-Korean and Yangtze cratons, the direction of fast propagation remains unchanged throughout the period range sampling the crust and lithospheric mantle. These observations suggest that the crust and lithospheric mantle are mechanically decoupled beneath eastern Tibet, and coupled beneath the Sino-Korean and Yangtze cratons.

Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization.

PubMed

Hoff, Daniel E M; Albert, Brice J; Saliba, Edward P; Scott, Faith J; Choi, Eric J; Mardini, Michael; Barnes, Alexander B

2015-11-01

Hyperfine decoupling and pulsed dynamic nuclear polarization (DNP) are promising techniques to improve high field DNP NMR. We explore experimental and theoretical considerations to implement them with magic angle spinning (MAS). Microwave field simulations using the high frequency structural simulator (HFSS) software suite are performed to characterize the inhomogeneous phase independent microwave field throughout a 198GHz MAS DNP probe. Our calculations show that a microwave power input of 17W is required to generate an average EPR nutation frequency of 0.84MHz. We also present a detailed calculation of microwave heating from the HFSS parameters and find that 7.1% of the incident microwave power contributes to dielectric sample heating. Voltage tunable gyrotron oscillators are proposed as a class of frequency agile microwave sources to generate microwave frequency sweeps required for the frequency modulated cross effect, electron spin inversions, and hyperfine decoupling. Electron spin inversions of stable organic radicals are simulated with SPINEVOLUTION using the inhomogeneous microwave fields calculated by HFSS. We calculate an electron spin inversion efficiency of 56% at a spinning frequency of 5kHz. Finally, we demonstrate gyrotron acceleration potentials required to generate swept microwave frequency profiles for the frequency modulated cross effect and electron spin inversions. Copyright © 2015 Elsevier Inc. All rights reserved.

Anthropocene Dialogues: Decoupling Economic Prosperity from Carbon Emissions

NASA Astrophysics Data System (ADS)

Tewksbury, J.; Kohm, K.

2017-12-01

Anthropocene magazine is a new science magazine produced by Future Earth. Its mission is to bring together the world's leading scientists, technologists, and creatives to explore on-the-ground stories of sustainability science in action. For AGU 2017, Anthropocene magazine will stage an "Anthropocene Dialogue" based on its July 2017 issue. Anthropocene Dialogues are panel discussions about the successes and challenges of transformative science-policy collaborations by leading science journalists, researchers, and practitioners. The focus of this dialogue is: What are the scientific and technological innovations that drive the decarbonization of economies—from plugging artificial intelligence into electrical grids to new experiments in solar geoengineering. Panelist include: Robert Jackson of the Global Carbon Project discussing the historic decoupling of carbon emissions from GDP, Oliver Morton of The Economist speaking on how geoengineering can be a key element of a decoupling process; Robinson Meyer of The Atlantic outlining a coal "retirement plan" based on supply side economics; Wayt Gibbs of Scientific American tackling the quintessential question, How much energy will the world need? and Mark Harris of IEEE Spectrum looking at new experiments in artificial intelligence that could pull fossil fuels out of electrical grids, factories, data centers, and transit systems. For more information on these stories, visit: anthropocenemagazine.org/in-print/. Free sample copies of the magazine will be available at the session.

Neural practice effect during cross-modal selective attention: Supra-modal and modality-specific effects.

PubMed

Xia, Jing; Zhang, Wei; Jiang, Yizhou; Li, You; Chen, Qi

2018-05-16

Practice and experiences gradually shape the central nervous system, from the synaptic level to large-scale neural networks. In natural multisensory environment, even when inundated by streams of information from multiple sensory modalities, our brain does not give equal weight to different modalities. Rather, visual information more frequently receives preferential processing and eventually dominates consciousness and behavior, i.e., visual dominance. It remains unknown, however, the supra-modal and modality-specific practice effect during cross-modal selective attention, and moreover whether the practice effect shows similar modality preferences as the visual dominance effect in the multisensory environment. To answer the above two questions, we adopted a cross-modal selective attention paradigm in conjunction with the hybrid fMRI design. Behaviorally, visual performance significantly improved while auditory performance remained constant with practice, indicating that visual attention more flexibly adapted behavior with practice than auditory attention. At the neural level, the practice effect was associated with decreasing neural activity in the frontoparietal executive network and increasing activity in the default mode network, which occurred independently of the modality attended, i.e., the supra-modal mechanisms. On the other hand, functional decoupling between the auditory and the visual system was observed with the progress of practice, which varied as a function of the modality attended. The auditory system was functionally decoupled with both the dorsal and ventral visual stream during auditory attention while was decoupled only with the ventral visual stream during visual attention. To efficiently suppress the irrelevant visual information with practice, auditory attention needs to additionally decouple the auditory system from the dorsal visual stream. The modality-specific mechanisms, together with the behavioral effect, thus support the visual dominance model in terms of the practice effect during cross-modal selective attention. Copyright © 2018 Elsevier Ltd. All rights reserved.

Breakdown of local information processing may underlie isoflurane anesthesia effects.

PubMed

Wollstadt, Patricia; Sellers, Kristin K; Rudelt, Lucas; Priesemann, Viola; Hutt, Axel; Fröhlich, Flavio; Wibral, Michael

2017-06-01

The disruption of coupling between brain areas has been suggested as the mechanism underlying loss of consciousness in anesthesia. This hypothesis has been tested previously by measuring the information transfer between brain areas, and by taking reduced information transfer as a proxy for decoupling. Yet, information transfer is a function of the amount of information available in the information source-such that transfer decreases even for unchanged coupling when less source information is available. Therefore, we reconsidered past interpretations of reduced information transfer as a sign of decoupling, and asked whether impaired local information processing leads to a loss of information transfer. An important prediction of this alternative hypothesis is that changes in locally available information (signal entropy) should be at least as pronounced as changes in information transfer. We tested this prediction by recording local field potentials in two ferrets after administration of isoflurane in concentrations of 0.0%, 0.5%, and 1.0%. We found strong decreases in the source entropy under isoflurane in area V1 and the prefrontal cortex (PFC)-as predicted by our alternative hypothesis. The decrease in source entropy was stronger in PFC compared to V1. Information transfer between V1 and PFC was reduced bidirectionally, but with a stronger decrease from PFC to V1. This links the stronger decrease in information transfer to the stronger decrease in source entropy-suggesting reduced source entropy reduces information transfer. This conclusion fits the observation that the synaptic targets of isoflurane are located in local cortical circuits rather than on the synapses formed by interareal axonal projections. Thus, changes in information transfer under isoflurane seem to be a consequence of changes in local processing more than of decoupling between brain areas. We suggest that source entropy changes must be considered whenever interpreting changes in information transfer as decoupling.

Covariance and decoupling of floral and vegetative traits in nine Neotropical plants: a re-evaluation of Berg's correlation-pleiades concept.

PubMed

Armbruster, W S; Di Stilio, V S; Tuxill, J D; Flores, T C; Velásquez Runk, J L

1999-01-01

Nearly forty years ago R. L. Berg proposed that plants with specialized pollination ecology evolve genetic and developmental systems that decouple floral morphology from phenotypic variation in vegetative traits. These species evolve separate floral and vegetative trait clusters, or as she termed them, "correlation pleiades." The predictions of this hypothesis have been generally supported, but only a small sample of temperate-zone herb and grass species has been tested. To further evaluate this hypothesis, especially its applicability to plants of other growth forms, we examined the patterns of phenotypic variation and covariation of floral and vegetative traits in nine species of Neotropical plants. We recognized seven specific predictions of Berg's hypothesis. Our results supported some predictions but not others. Species with specialized pollination systems usually had floral traits decoupled (weak correlation; Canna and Eichornia) or buffered (relationship with shallow proportional slope; Calathea and Canna) from variation in vegetative traits. However, the same trend was also observed in three species with unspecialized pollination systems (Echinodorus, Muntingia, and Wedelia). One species with unspecialized pollination (Croton) and one wind-pollinated species (Cyperus) showed no decoupling or buffering, as predicted. While species with specialized pollination usually showed lower coefficients of variation for floral traits than vegetative traits (as predicted), the same was also true of species with unspecialized or wind pollination (unlike our prediction). Species with specialized pollination showed less variation in floral traits than did species with unspecialized or wind pollination, as predicted. However, the same was true of the corresponding vegetative traits, which was unexpected. Also in contrast to our prediction, plants with specialized pollination systems did not exhibit tighter phenotypic integration of floral characters than did species with generalized pollination systems. We conclude that the patterns of morphological integration among floral traits and between floral and vegetative traits tend to be species specific, not easily predicted from pollination ecology, and generally more complicated than R. L. Berg envisaged.

Breakdown of local information processing may underlie isoflurane anesthesia effects

PubMed Central

Sellers, Kristin K.; Priesemann, Viola; Hutt, Axel

2017-01-01

The disruption of coupling between brain areas has been suggested as the mechanism underlying loss of consciousness in anesthesia. This hypothesis has been tested previously by measuring the information transfer between brain areas, and by taking reduced information transfer as a proxy for decoupling. Yet, information transfer is a function of the amount of information available in the information source—such that transfer decreases even for unchanged coupling when less source information is available. Therefore, we reconsidered past interpretations of reduced information transfer as a sign of decoupling, and asked whether impaired local information processing leads to a loss of information transfer. An important prediction of this alternative hypothesis is that changes in locally available information (signal entropy) should be at least as pronounced as changes in information transfer. We tested this prediction by recording local field potentials in two ferrets after administration of isoflurane in concentrations of 0.0%, 0.5%, and 1.0%. We found strong decreases in the source entropy under isoflurane in area V1 and the prefrontal cortex (PFC)—as predicted by our alternative hypothesis. The decrease in source entropy was stronger in PFC compared to V1. Information transfer between V1 and PFC was reduced bidirectionally, but with a stronger decrease from PFC to V1. This links the stronger decrease in information transfer to the stronger decrease in source entropy—suggesting reduced source entropy reduces information transfer. This conclusion fits the observation that the synaptic targets of isoflurane are located in local cortical circuits rather than on the synapses formed by interareal axonal projections. Thus, changes in information transfer under isoflurane seem to be a consequence of changes in local processing more than of decoupling between brain areas. We suggest that source entropy changes must be considered whenever interpreting changes in information transfer as decoupling. PMID:28570661

Hubble space telescope imaging of decoupled dust clouds in the ram pressure stripped Virgo spirals NGC 4402 and NGC 4522

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

Abramson, Anne; Kenney, Jeffrey D. P., E-mail: anne.abramson@yale.edu, E-mail: jeff.kenney@yale.edu

We present the highest-resolution study to date of the interstellar medium (ISM) in galaxies undergoing ram pressure stripping, using Hubble Space Telescope BVI imaging of NGC 4522 and NGC 4402, Virgo Cluster spirals that are well known to be experiencing intracluster medium (ICM) ram pressure. We find that throughout most of both galaxies, the main dust lane has a fairly well-defined edge, with a population of giant molecular cloud (GMC) sized (tens- to hundreds-of-pc scale), isolated, highly extincting dust clouds located up to ∼1.5 kpc radially beyond it. Outside of these dense clouds, the area has little or no diffusemore » dust extinction, indicating that the clouds have decoupled from the lower-density ISM material that has already been stripped. Several of the dust clouds have elongated morphologies that indicate active ram pressure, including two large (kpc scale) filaments in NGC 4402 that are elongated in the projected ICM wind direction. We calculate a lower limit on the H I + H{sub 2} masses of these clouds based on their dust extinctions and find that a correction factor of ∼10 gives cloud masses consistent with those measured in CO for clouds of similar diameters, probably due to the complicating factors of foreground light, cloud substructure, and resolution limitations. Assuming that the clouds' actual masses are consistent with those of GMCs of similar diameters (∼10{sup 4}-10{sup 5} M {sub ☉}), we estimate that only a small fraction (∼1%-10%) of the original H I + H{sub 2} remains in the parts of the disks with decoupled clouds. Based on Hα images, a similar fraction of star formation persists in these regions, 2%-3% of the estimated pre-stripping star formation rate. We find that the decoupled cloud lifetimes may be up to 150-200 Myr.« less

Slab detachment during continental collision: Influence of crustal rheology and interaction with lithospheric delamination

NASA Astrophysics Data System (ADS)

Duretz, T.; Gerya, T. V.

2013-08-01

Collision between continents can lead to the subduction of continental material. If the crust remains coupled to the downgoing slab, a large buoyancy force is generated. This force slows down convergence and promotes slab detachment. If the crust resists to subduction, it may decouple from the downgoing slab and be subjected to buoyant extrusion. We employ two-dimensional thermo-mechanical modelling to study the importance of crustal rheology on the evolution of subduction-collision systems. We propose simple quantifications of the mechanical decoupling between lithospheric levels (σ*) and the potential for buoyant extrusion of the crust (ξ*). The modelling results indicate that a variable crustal rheological structure results in slab detachment, delamination, or the combination of both mechanisms. A strong crust provides coupling at the Moho (low σ*) and remains coherent during subduction (low ξ). It promotes deep subduction of the crust (180 km) and slab detachment. Exhumation occurs in coherent manners via eduction and thrusting. Slab detachment triggers the development of topography (> 4.5 km) close to the suture. A contrasting style of collision occurs using a weak crustal rheology. Mechanical decoupling at the Moho (high σ*) promotes the extrusion of the crust (high ξ), disabling slab detachment. Ongoing shortening leads to buckling of the crust and development of topography on the lower plate. Collisions involving rheologically layered crust allow decoupling at mid-crustal depths. This structure favours both the extrusion of upper crust and the subduction of the lower crust. Such collisions are successively affected by delamination and slab detachment. Topography develops together with the buoyant extrusion of crust onto the foreland and is further amplified by slab detachment. Our results suggest that the occurrence of both delamination (Apennines) and slab detachment (Himalayas) in orogens may indicate differences in the initial crustal structure of subducting continental plates in these regions.

The situated HKB model: how sensorimotor spatial coupling can alter oscillatory brain dynamics

PubMed Central

Aguilera, Miguel; Bedia, Manuel G.; Santos, Bruno A.; Barandiaran, Xabier E.

2013-01-01

Despite the increase of both dynamic and embodied/situated approaches in cognitive science, there is still little research on how coordination dynamics under a closed sensorimotor loop might induce qualitatively different patterns of neural oscillations compared to those found in isolated systems. We take as a departure point the Haken-Kelso-Bunz (HKB) model, a generic model for dynamic coordination between two oscillatory components, which has proven useful for a vast range of applications in cognitive science and whose dynamical properties are well understood. In order to explore the properties of this model under closed sensorimotor conditions we present what we call the situated HKB model: a robotic model that performs a gradient climbing task and whose “brain” is modeled by the HKB equation. We solve the differential equations that define the agent-environment coupling for increasing values of the agent's sensitivity (sensor gain), finding different behavioral strategies. These results are compared with two different models: a decoupled HKB with no sensory input and a passively-coupled HKB that is also decoupled but receives a structured input generated by a situated agent. We can precisely quantify and qualitatively describe how the properties of the system, when studied in coupled conditions, radically change in a manner that cannot be deduced from the decoupled HKB models alone. We also present the notion of neurodynamic signature as the dynamic pattern that correlates with a specific behavior and we show how only a situated agent can display this signature compared to an agent that simply receives the exact same sensory input. To our knowledge, this is the first analytical solution of the HKB equation in a sensorimotor loop and qualitative and quantitative analytic comparison of spatially coupled vs. decoupled oscillatory controllers. Finally, we discuss the limitations and possible generalization of our model to contemporary neuroscience and philosophy of mind. PMID:23986692

Ideas and perspectives: how coupled is the vegetation to the boundary layer?

NASA Astrophysics Data System (ADS)

De Kauwe, Martin G.; Medlyn, Belinda E.; Knauer, Jürgen; Williams, Christopher A.

2017-10-01

Understanding the sensitivity of transpiration to stomatal conductance is critical to simulating the water cycle. This sensitivity is a function of the degree of coupling between the vegetation and the atmosphere and is commonly expressed by the decoupling factor. The degree of coupling assumed by models varies considerably and has previously been shown to be a major cause of model disagreement when simulating changes in transpiration in response to elevated CO2. The degree of coupling also offers us insight into how different vegetation types control transpiration fluxes, which is fundamental to our understanding of land-atmosphere interactions. To explore this issue, we combined an extensive literature summary from 41 studies with estimates of the decoupling coefficient estimated from FLUXNET data. We found some notable departures from the values previously reported in single-site studies. There was large variability in estimated decoupling coefficients (range 0.05-0.51) for evergreen needleleaf forests. This is a result that was broadly supported by our literature review but contrasts with the early literature which suggests that evergreen needleleaf forests are generally well coupled. Estimates from FLUXNET indicated that evergreen broadleaved forests were the most tightly coupled, differing from our literature review and instead suggesting that it was evergreen needleleaf forests. We also found that the assumption that grasses would be strongly decoupled (due to vegetation stature) was only true for high precipitation sites. These results were robust to assumptions about aerodynamic conductance and, to a lesser extent, energy balance closure. Thus, these data form a benchmarking metric against which to test model assumptions about coupling. Our results identify a clear need to improve the quantification of the processes involved in scaling from the leaf to the whole ecosystem. Progress could be made with targeted measurement campaigns at flux sites and greater site characteristic information across the FLUXNET network.

HST Imaging of Dust Structures and Stars in the Ram Pressure Stripped Virgo Spirals NGC 4402 and NGC 4522: Stripped from the Outside In with Dense Cloud Decoupling

NASA Astrophysics Data System (ADS)

Abramson, A.; Kenney, J.; Crowl, H.; Tal, T.

2016-08-01

We describe and constrain the origins of interstellar medium (ISM) structures likely created by ongoing intracluster medium (ICM) ram pressure stripping in two Virgo Cluster spirals, NGC 4522 and NGC 4402, using Hubble Space Telescope (HST) BVI images of dust extinction and stars, as well as supplementary H I, Hα, and radio continuum images. With a spatial resolution of ˜10 pc in the HST images, this is the highest-resolution study to date of the physical processes that occur during an ICM-ISM ram pressure stripping interaction, ram pressure stripping's effects on the multi-phase, multi-density ISM, and the formation and evolution of ram-pressure-stripped tails. In dust extinction, we view the leading side of NGC 4402 and the trailing side of NGC 4522, and so we see distinct types of features in both. In both galaxies, we identify some regions where dense clouds are decoupling or have decoupled and others where it appears that kiloparsec-sized sections of the ISM are moving coherently. NGC 4522 has experienced stronger, more recent pressure and has the “jellyfish” morphology characteristic of some ram-pressure-stripped galaxies. Its stripped tail extends up from the disk plane in continuous upturns of dust and stars curving up to ˜2 kpc above the disk plane. On the other side of the galaxy, there is a kinematically and morphologically distinct extraplanar arm of young, blue stars and ISM above a mostly stripped portion of the disk, and between it and the disk plane are decoupled dust clouds that have not been completely stripped. The leading side of NGC 4402 contains two kiloparsec-scale linear dust filaments with complex substructure that have partially decoupled from the surrounding ISM. NGC 4402 also contains long dust ridges, suggesting that large parts of the ISM are being pushed out at once. Both galaxies contain long ridges of polarized radio continuum emission indicating the presence of large-scale, ordered magnetic fields. We propose that magnetic fields could bind together gas of different densities, causing nearby gas of different densities to be stripped at the same rate and creating the large, coherent dust ridges and upturns. A number of factors likely play roles in determining what types of structures form as a result of ram pressure, including ram pressure strength and history, the location within the galaxy relative to the leading side, and pre-existing substructure in the ISM that may be bound together by magnetic fields during stripping.

Continental sedimentary processes decouple Nd and Hf isotopes

NASA Astrophysics Data System (ADS)

Garçon, Marion; Chauvel, Catherine; France-Lanord, Christian; Huyghe, Pascale; Lavé, Jérôme

2013-11-01

The neodymium and hafnium isotopic compositions of most crustal and mantle rocks correlate to form the "Terrestrial Array". However, it is now well established that whereas coarse detrital sediments follow this trend, fine-grained oceanic sediments have high Hf ratios relative to their Nd isotopic ratios. It remains uncertain whether this "decoupling" of the two isotopic systems only occurs in the oceanic environment or if it is induced by sedimentary processes in continental settings. In this study, the hafnium and neodymium isotopic compositions of sediments in large rivers is expressly used to constrain the behavior of the two isotopic systems during erosion and sediment transport from continent to ocean. We report major and trace element concentrations together with Nd and Hf isotopic compositions of bedloads, suspended loads and river banks from the Ganges River and its tributaries draining the Himalayan Range i.e. the Karnali, the Narayani, the Kosi and the Marsyandi Rivers. The sample set includes sediments sampled within the Himalayan Range in Nepal, at the Himalayan mountain front, and also downstream on the floodplain and at the outflow of the Ganges in Bangladesh. Results show that hydrodynamic sorting of minerals explains the entire Hf isotopic range, i.e. more than 10 εHf units, observed in the river sediments but does not affect the Nd isotopic composition. Bedloads and bank sediments have systematically lower εHf values than suspended loads sampled at the same location. Coarse-grained sediments lie below or on the Terrestrial Array in an εHf vs. εNd diagram. In contrast, fine-grained sediments, including most of the suspended loads, deviate from the Terrestrial Array toward higher εHf relative to their εNd, as is the case for oceanic terrigenous clays. The observed Nd-Hf decoupling is explained by mineralogical sorting processes that enrich bottom sediments in coarse and dense minerals, including unradiogenic zircons, while surface sediments are enriched in fine material with radiogenic Hf signatures. The data also show that Nd-Hf isotopic decoupling increases with sediment transport in the floodplain to reach its maximum at the river mouth. This implies that the Nd-Hf isotopic decoupling observed in worldwide oceanic clays and river sediments is likely to have the same origin. Finally, we estimated the Nd-Hf isotopic composition of the present-day mantle if oceanic sediments had never been subducted and conclude that the addition of oceanic sediments with their anomalous Nd-Hf isotopic compositions has slowly shifted the composition of the Earth's mantle towards more radiogenic Hf values through time.

Performance of thin-film ferroelectric capacitors for EMC decoupling.

PubMed

Li, Huadong; Subramanyam, Guru

2008-12-01

This paper studied the effects of thin-film ferroelectrics as decoupling capacitors for electromagnetic compatibility applications. The impedance and insertion loss of PZT capacitors were measured and compared with the results from commercial off-the-shelf capacitors. An equivalent circuit model was extracted from the experimental results, and a considerable series resistance was found to exist in ferroelectric capacitors. This resistance gives rise to the observed performance difference around series resonance between ferroelectric PZT capacitors and normal capacitors. Measurements on paraelectric (Ba,Sr)TiO(3)-based integrated varactors do not show this significant resistance. Some analyses were made to investigate the mechanisms, and it was found that it can be due to the hysteresis in the ferroelectric thin films.

Response to “Comment on ‘Rethinking first-principles electron transport theories with projection operators: The problems caused by partitioning the basis set’” [J. Chem. Phys. 140, 177103 (2014)

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

Reuter, Matthew G., E-mail: mgreuter@u.northwestern.edu; Harrison, Robert J.

2014-05-07

The thesis of Brandbyge's comment [J. Chem. Phys. 140, 177103 (2014)] is that our operator decoupling condition is immaterial to transport theories, and it appeals to discussions of nonorthogonal basis sets in transport calculations in its arguments. We maintain that the operator condition is to be preferred over the usual matrix conditions and subsequently detail problems in the existing approaches. From this operator perspective, we conclude that nonorthogonal projectors cannot be used and that the projectors must be selected to satisfy the operator decoupling condition. Because these conclusions pertain to operators, the choice of basis set is not germane.

The impact of no-fault compensation on health care expenditures: an empirical study of OECD countries.

PubMed

Vandersteegen, Tom; Marneffe, Wim; Cleemput, Irina; Vereeck, Lode

2015-03-01

Around the world, governments are faced with spiralling health care expenditures. This raises the need for further insight in the determinants of these expenditures. Existing literature focuses primarily on income, ageing, health care financing and supply variables. This paper includes medical malpractice system characteristics as determinants of health spending in OECD countries. Estimates from our regression models suggest that no-fault schemes for medical injuries with decoupling of deterrence and compensation reduce health expenditures per capita by 0.11%. Furthermore, countries that introduced a no-fault system without decoupling of deterrence and compensation are found to have higher (+0.06%) health care spending. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

On-Demand Microwave Generator of Shaped Single Photons

NASA Astrophysics Data System (ADS)

Forn-Díaz, P.; Warren, C. W.; Chang, C. W. S.; Vadiraj, A. M.; Wilson, C. M.

2017-11-01

We demonstrate the full functionality of a circuit that generates single microwave photons on demand, with a wave packet that can be modulated with a near-arbitrary shape. We achieve such a high tunability by coupling a superconducting qubit near the end of a semi-infinite transmission line. A dc superconducting quantum interference device shunts the line to ground and is employed to modify the spatial dependence of the electromagnetic mode structure in the transmission line. This control allows us to couple and decouple the qubit from the line, shaping its emission rate on fast time scales. Our decoupling scheme is applicable to all types of superconducting qubits and other solid-state systems and can be generalized to multiple qubits as well as to resonators.

Parameterized LMI Based Diagonal Dominance Compensator Study for Polynomial Linear Parameter Varying System

NASA Astrophysics Data System (ADS)

Han, Xiaobao; Li, Huacong; Jia, Qiusheng

2017-12-01

For dynamic decoupling of polynomial linear parameter varying(PLPV) system, a robust dominance pre-compensator design method is given. The parameterized precompensator design problem is converted into an optimal problem constrained with parameterized linear matrix inequalities(PLMI) by using the conception of parameterized Lyapunov function(PLF). To solve the PLMI constrained optimal problem, the precompensator design problem is reduced into a normal convex optimization problem with normal linear matrix inequalities (LMI) constraints on a new constructed convex polyhedron. Moreover, a parameter scheduling pre-compensator is achieved, which satisfies robust performance and decoupling performances. Finally, the feasibility and validity of the robust diagonal dominance pre-compensator design method are verified by the numerical simulation on a turbofan engine PLPV model.

The first observation of Carbon-13 spin noise spectra

PubMed Central

Schlagnitweit, Judith; Müller, Norbert

2012-01-01

We demonstrate the first 13C NMR spin noise spectra obtained without any pulse excitation by direct detection of the randomly fluctuating noise from samples in a cryogenically cooled probe. Noise power spectra were obtained from 13C enriched methanol and glycerol samples at 176 MHz without and with 1H decoupling, which increases the sensitivity without introducing radio frequency interference with the weak spin noise. The multiplet amplitude ratios in 1H coupled spectra indicate that, although pure spin noise prevails in these spectra, the influence of absorbed circuit noise is still significant at the high concentrations used. In accordance with the theory heteronuclear Overhauser enhancements are absent from the 1H-decoupled 13C spin noise spectra. PMID:23041799

Decoupled 1D/3D analysis of a hydraulic valve

NASA Astrophysics Data System (ADS)

Mehring, Carsten; Zopeya, Ashok; Latham, Matt; Ihde, Thomas; Massie, Dan

2014-10-01

Analysis approaches during product development of fluid valves and other aircraft fluid delivery components vary greatly depending on the development stage. Traditionally, empirical or simplistic one-dimensional tools are being deployed during preliminary design, whereas detailed analysis such as CFD (Computational Fluid Dynamics) tools are used to refine a selected design during the detailed design stage. In recent years, combined 1D/3D co-simulation has been deployed specifically for system level simulations requiring an increased level of analysis detail for one or more components. The present paper presents a decoupled 1D/3D analysis approach where 3D CFD analysis results are utilized to enhance the fidelity of a dynamic 1D modelin context of an aircraft fuel valve.

Fast calculation of the line-spread-function by transversal directions decoupling

NASA Astrophysics Data System (ADS)

Parravicini, Jacopo; Tartara, Luca; Hasani, Elton; Tomaselli, Alessandra

2016-07-01

We propose a simplified method to calculate the optical spread function of a paradigmatic system constituted by a pupil-lens with a line-shaped illumination (‘line-spread-function’). Our approach is based on decoupling the two transversal directions of the beam and treating the propagation by means of the Fourier optics formalism. This requires simpler calculations with respect to the more usual Bessel-function-based method. The model is discussed and compared with standard calculation methods by carrying out computer simulations. The proposed approach is found to be much faster than the Bessel-function-based one (CPU time ≲ 5% of the standard method), while the results of the two methods present a very good mutual agreement.

Pulsed dynamical decoupling for fast and robust two-qubit gates on trapped ions

NASA Astrophysics Data System (ADS)

Arrazola, I.; Casanova, J.; Pedernales, J. S.; Wang, Z.-Y.; Solano, E.; Plenio, M. B.

2018-05-01

We propose a pulsed dynamical decoupling protocol as the generator of tunable, fast, and robust quantum phase gates between two microwave-driven trapped-ion hyperfine qubits. The protocol consists of sequences of π pulses acting on ions that are oriented along an externally applied magnetic-field gradient. In contrast to existing approaches, in our design the two vibrational modes of the ion chain cooperate under the influence of the external microwave driving to achieve significantly increased gate speeds. Our scheme is robust against the dominant noise sources, which are errors on the magnetic-field and microwave pulse intensities, as well as motional heating, predicting two-qubit gates with fidelities above 99.9% in tens of microseconds.

Decoupling the refractive index from the electrical properties of transparent conducting oxides via periodic superlattices.

PubMed

Caffrey, David; Norton, Emma; Coileáin, Cormac Ó; Smith, Christopher M; Bulfin, Brendan; Farrell, Leo; Shvets, Igor V; Fleischer, Karsten

2016-09-13

We demonstrate an alternative approach to tuning the refractive index of materials. Current methodologies for tuning the refractive index of a material often result in undesirable changes to the structural or optoelectronic properties. By artificially layering a transparent conducting oxide with a lower refractive index material the overall film retains a desirable conductivity and mobility while acting optically as an effective medium with a modified refractive index. Calculations indicate that, with our refractive index change of 0.2, a significant reduction of reflective losses could be obtained by the utilisation of these structures in optoelectronic devices. Beyond this, periodic superlattice structures present a solution to decouple physical properties where the underlying electronic interaction is governed by different length scales.

Compact antenna for efficient and unidirectional launching and decoupling of surface plasmons.

PubMed

Baron, Alexandre; Devaux, Eloïse; Rodier, Jean-Claude; Hugonin, Jean-Paul; Rousseau, Emmanuel; Genet, Cyriaque; Ebbesen, Thomas W; Lalanne, Philippe

2011-10-12

Controlling the launching efficiencies and the directionality of surface plasmon polaritons (SPPs) and their decoupling to freely propagating light is a major goal for the development of plasmonic devices and systems. Here, we report on the design and experimental observation of a highly efficient unidirectional surface plasmon launcher composed of eleven subwavelength grooves, each with a distinct depth and width. Our observations show that, under normal illumination by a focused Gaussian beam, unidirectional SPP launching with an efficiency of at least 52% is achieved experimentally with a compact device of total length smaller than 8 μm. Reciprocally, we report that the same device can efficiently convert SPPs into a highly directive light beam emanating perpendicularly to the sample.

A Two Colorable Fourth Order Compact Difference Scheme and Parallel Iterative Solution of the 3D Convection Diffusion Equation

NASA Technical Reports Server (NTRS)

Zhang, Jun; Ge, Lixin; Kouatchou, Jules

2000-01-01

A new fourth order compact difference scheme for the three dimensional convection diffusion equation with variable coefficients is presented. The novelty of this new difference scheme is that it Only requires 15 grid points and that it can be decoupled with two colors. The entire computational grid can be updated in two parallel subsweeps with the Gauss-Seidel type iterative method. This is compared with the known 19 point fourth order compact differenCe scheme which requires four colors to decouple the computational grid. Numerical results, with multigrid methods implemented on a shared memory parallel computer, are presented to compare the 15 point and the 19 point fourth order compact schemes.

Nondecoupling of maximal supergravity from the superstring.

PubMed

Green, Michael B; Ooguri, Hirosi; Schwarz, John H

2007-07-27

We consider the conditions necessary for obtaining perturbative maximal supergravity in d dimensions as a decoupling limit of type II superstring theory compactified on a (10-d) torus. For dimensions d=2 and d=3, it is possible to define a limit in which the only finite-mass states are the 256 massless states of maximal supergravity. However, in dimensions d>or=4, there are infinite towers of additional massless and finite-mass states. These correspond to Kaluza-Klein charges, wound strings, Kaluza-Klein monopoles, or branes wrapping around cycles of the toroidal extra dimensions. We conclude that perturbative supergravity cannot be decoupled from string theory in dimensions>or=4. In particular, we conjecture that pure N=8 supergravity in four dimensions is in the Swampland.

On the accuracy of the 'decoupled l-dominant' approximation for atom-molecule scattering

NASA Technical Reports Server (NTRS)

Green, S.

1976-01-01

Cross sections for rotational excitation and spectral pressure broadening of HD, HCl, CO, and HCN due to collisions with low energy He atoms have been computed within the 'decoupled l-dominant' (DLD) approximation and are compared with accurate close coupling results and also with two similar approximations, the effective potential of Rabitz and the coupled states of McGuire and Kouri. DLD predictions of state-to-state cross sections are rather good, being only slightly less accurate than coupled states results. DLD is far superior to either the coupled states or effective potential methods for pressure broadening calculations, although it may not be uniformly of the quantitative accuracy desirable for obtaining intermolecular potentials from experimental data.

Demonstration of entanglement of electrostatically coupled singlet-triplet qubits.

PubMed

Shulman, M D; Dial, O E; Harvey, S P; Bluhm, H; Umansky, V; Yacoby, A

2012-04-13

Quantum computers have the potential to solve certain problems faster than classical computers. To exploit their power, it is necessary to perform interqubit operations and generate entangled states. Spin qubits are a promising candidate for implementing a quantum processor because of their potential for scalability and miniaturization. However, their weak interactions with the environment, which lead to their long coherence times, make interqubit operations challenging. We performed a controlled two-qubit operation between singlet-triplet qubits using a dynamically decoupled sequence that maintains the two-qubit coupling while decoupling each qubit from its fluctuating environment. Using state tomography, we measured the full density matrix of the system and determined the concurrence and the fidelity of the generated state, providing proof of entanglement.

Decoupling emissions of greenhouse gas, urbanization, energy and income: analysis from the economy of China.

PubMed

Wang, Tianqiong; Riti, Joshua Sunday; Shu, Yang

2018-05-08

The adoption and ratification of relevant policies, particularly the household enrolment system metamorphosis in China, led to rising urbanization growth. As the leading developing economy, China has experienced a drastic and rapid increase in the rate of urbanization, energy use, economic growth and greenhouse gas (GHG) pollution for the past 30 years. The knowledge of the dynamic interrelationships among these trends has a plethora of implications ranging from demographic, energy, and environmental and sustainable development policies. This study analyzes the role of urbanization in decoupling GHG emissions, energy, and income in China while considering the critical contribution of energy use. As a contribution to the extant body of literature, the present research introduces a new phenomenon called "the environmental urbanization Kuznets curve" (EUKC), which shows that at the early stage of urbanization, the environment degrades however, after a threshold point the technique effects surface and environmental degradation reduces with rise in urbanization. Applying the autoregressive distributed lag model and the vector error correction model, the paper finds the presence of inverted U-shaped curve between urbanization and GHG emission of CO 2 , while the same hypothesis cannot be found between income and GHG emission of CO 2 . Energy use in all the models contributes to GHG emission of CO 2 . In decoupling greenhouse gas emissions, urbanization, energy, and income, articulated and well-implemented energy and urbanization policies should be considered.

High-Accuracy Decoupling Estimation of the Systematic Coordinate Errors of an INS and Intensified High Dynamic Star Tracker Based on the Constrained Least Squares Method

PubMed Central

Jiang, Jie; Yu, Wenbo; Zhang, Guangjun

2017-01-01

Navigation accuracy is one of the key performance indicators of an inertial navigation system (INS). Requirements for an accuracy assessment of an INS in a real work environment are exceedingly urgent because of enormous differences between real work and laboratory test environments. An attitude accuracy assessment of an INS based on the intensified high dynamic star tracker (IHDST) is particularly suitable for a real complex dynamic environment. However, the coupled systematic coordinate errors of an INS and the IHDST severely decrease the attitude assessment accuracy of an INS. Given that, a high-accuracy decoupling estimation method of the above systematic coordinate errors based on the constrained least squares (CLS) method is proposed in this paper. The reference frame of the IHDST is firstly converted to be consistent with that of the INS because their reference frames are completely different. Thereafter, the decoupling estimation model of the systematic coordinate errors is established and the CLS-based optimization method is utilized to estimate errors accurately. After compensating for error, the attitude accuracy of an INS can be assessed based on IHDST accurately. Both simulated experiments and real flight experiments of aircraft are conducted, and the experimental results demonstrate that the proposed method is effective and shows excellent performance for the attitude accuracy assessment of an INS in a real work environment. PMID:28991179

Self-induced pinning of vortices in the presence of ac driving force in magnetic superconductors

NASA Astrophysics Data System (ADS)

Bulaevskii, Lev N.; Lin, Shi-Zeng

2012-12-01

We derive the response of the magnetic superconductors in the vortex state to the ac Lorentz force, FL(t)=Facsin(ωt), taking into account the interaction of vortices with the magnetic moments described by the relaxation dynamics (polaronic effect). At low amplitudes of the driving force Fac the dissipation in the system is suppressed due to the enhancement of the effective viscosity at low frequencies and due to formation of the magnetic pinning at high frequencies ω. In the adiabatic limit with low frequencies ω and high amplitude of the driving force Fac, the vortex and magnetic polarization form a vortex polaron when FL(t) is small. When FL increases, the vortex polaron accelerates and at a threshold driving force, the vortex polaron dissociates and the motion of vortex and the relaxation of magnetization are decoupled. When FL decreases, the vortex is retrapped by the background of remnant magnetization and they again form vortex polaron. This process repeats when FL(t) increases in the opposite direction. Remarkably, after dissociation, decoupled vortices move in the periodic potential induced by magnetization which remains for some periods of time due to retardation after the decoupling. At this stage vortices oscillate with high frequencies determined by the Lorentz force at the moment of dissociation. We derive also the creep rate of vortices and show that magnetic moments suppress creep rate.

An efficient numerical solution of the transient storage equations for solute transport in small streams

USGS Publications Warehouse

Runkel, Robert L.; Chapra, Steven C.

1993-01-01

Several investigators have proposed solute transport models that incorporate the effects of transient storage. Transient storage occurs in small streams when portions of the transported solute become isolated in zones of water that are immobile relative to water in the main channel (e.g., pools, gravel beds). Transient storage is modeled by adding a storage term to the advection-dispersion equation describing conservation of mass for the main channel. In addition, a separate mass balance equation is written for the storage zone. Although numerous applications of the transient storage equations may be found in the literature, little attention has been paid to the numerical aspects of the approach. Of particular interest is the coupled nature of the equations describing mass conservation for the main channel and the storage zone. In the work described herein, an implicit finite difference technique is developed that allows for a decoupling of the governing differential equations. This decoupling method may be applied to other sets of coupled equations such as those describing sediment-water interactions for toxic contaminants. For the case at hand, decoupling leads to a 50% reduction in simulation run time. Computational costs may be further reduced through efficient application of the Thomas algorithm. These techniques may be easily incorporated into existing codes and new applications in which simulation run time is of concern.

Multi-qubit gates protected by adiabaticity and dynamical decoupling applicable to donor qubits in silicon

DOE PAGES

Witzel, Wayne; Montano, Ines; Muller, Richard P.; ...

2015-08-19

In this paper, we present a strategy for producing multiqubit gates that promise high fidelity with minimal tuning requirements. Our strategy combines gap protection from the adiabatic theorem with dynamical decoupling in a complementary manner. Energy-level transition errors are protected by adiabaticity and remaining phase errors are mitigated via dynamical decoupling. This is a powerful way to divide and conquer the various error channels. In order to accomplish this without violating a no-go theorem regarding black-box dynamically corrected gates [Phys. Rev. A 80, 032314 (2009)], we require a robust operating point (sweet spot) in control space where the qubits interactmore » with little sensitivity to noise. There are also energy gap requirements for effective adiabaticity. We apply our strategy to an architecture in Si with P donors where we assume we can shuttle electrons between different donors. Electron spins act as mobile ancillary qubits and P nuclear spins act as long-lived data qubits. Furthermore, this system can have a very robust operating point where the electron spin is bound to a donor in the quadratic Stark shift regime. High fidelity single qubit gates may be performed using well-established global magnetic resonance pulse sequences. Single electron-spin preparation and measurement has also been demonstrated. Thus, putting this all together, we present a robust universal gate set for quantum computation.« less

Does Spike-Timing-Dependent Synaptic Plasticity Couple or Decouple Neurons Firing in Synchrony?

PubMed Central

Knoblauch, Andreas; Hauser, Florian; Gewaltig, Marc-Oliver; Körner, Edgar; Palm, Günther

2012-01-01

Spike synchronization is thought to have a constructive role for feature integration, attention, associative learning, and the formation of bidirectionally connected Hebbian cell assemblies. By contrast, theoretical studies on spike-timing-dependent plasticity (STDP) report an inherently decoupling influence of spike synchronization on synaptic connections of coactivated neurons. For example, bidirectional synaptic connections as found in cortical areas could be reproduced only by assuming realistic models of STDP and rate coding. We resolve this conflict by theoretical analysis and simulation of various simple and realistic STDP models that provide a more complete characterization of conditions when STDP leads to either coupling or decoupling of neurons firing in synchrony. In particular, we show that STDP consistently couples synchronized neurons if key model parameters are matched to physiological data: First, synaptic potentiation must be significantly stronger than synaptic depression for small (positive or negative) time lags between presynaptic and postsynaptic spikes. Second, spike synchronization must be sufficiently imprecise, for example, within a time window of 5–10 ms instead of 1 ms. Third, axonal propagation delays should not be much larger than dendritic delays. Under these assumptions synchronized neurons will be strongly coupled leading to a dominance of bidirectional synaptic connections even for simple STDP models and low mean firing rates at the level of spontaneous activity. PMID:22936909

Cosmic acceleration and the helicity-0 graviton

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

Rham, Claudia de; Heisenberg, Lavinia; Gabadadze, Gregory

2011-05-15

We explore cosmology in the decoupling limit of a nonlinear covariant extension of Fierz-Pauli massive gravity obtained recently in arXiv:1007.0443. In this limit the theory is a scalar-tensor model of a unique form defined by symmetries. We find that it admits a self-accelerated solution, with the Hubble parameter set by the graviton mass. The negative pressure causing the acceleration is due to a condensate of the helicity-0 component of the massive graviton, and the background evolution, in the approximation used, is indistinguishable from the {Lambda}CDM model. Fluctuations about the self-accelerated background are stable for a certain range of parameters involved.more » Most surprisingly, the fluctuation of the helicity-0 field above its background decouples from an arbitrary source in the linearized theory. We also show how massive gravity can remarkably screen an arbitrarily large cosmological constant in the decoupling limit, while evading issues with ghosts. The obtained static solution is stable against small perturbations, suggesting that the degravitation of the vacuum energy is possible in the full theory. Interestingly, however, this mechanism postpones the Vainshtein effect to shorter distance scales. Hence, fifth force measurements severely constrain the value of the cosmological constant that can be neutralized, making this scheme phenomenologically not viable for solving the old cosmological constant problem. We briefly speculate on a possible way out of this issue.« less

Evolution of tripartite entangled states in a decohering environment and their experimental protection using dynamical decoupling

NASA Astrophysics Data System (ADS)

Singh, Harpreet; Arvind, Dorai, Kavita

2018-02-01

We embarked upon the task of experimental protection of different classes of tripartite entangled states, namely, the maximally entangled Greenberger-Horne-Zeilinger (GHZ) and W states and the tripartite entangled state called the W W ¯ state, using dynamical decoupling. The states were created on a three-qubit NMR quantum information processor and allowed to evolve in the naturally noisy NMR environment. Tripartite entanglement was monitored at each time instant during state evolution, using negativity as an entanglement measure. It was found that the W state is most robust while the GHZ-type states are most fragile against the natural decoherence present in the NMR system. The W W ¯ state, which is in the GHZ class yet stores entanglement in a manner akin to the W state, surprisingly turned out to be more robust than the GHZ state. The experimental data were best modeled by considering the main noise channel to be an uncorrelated phase damping channel acting independently on each qubit, along with a generalized amplitude damping channel. Using dynamical decoupling, we were able to achieve a significant protection of entanglement for GHZ states. There was a marginal improvement in the state fidelity for the W state (which is already robust against natural system decoherence), while the W W ¯ state showed a significant improvement in fidelity and protection against decoherence.

Seeing a straight line on a curved surface: decoupling of patterns from surfaces by single IT neurons

PubMed Central

Ratan Murty, N. Apurva

2016-01-01

We have no difficulty seeing a straight line drawn on a paper even when the paper is bent, but this inference is in fact nontrivial. Doing so requires either matching local features or representing the pattern after factoring out the surface shape. Here we show that single neurons in the monkey inferior temporal (IT) cortex show invariant responses to patterns across rigid and nonrigid changes of surfaces. We recorded neuronal responses to stimuli in which the pattern and the surrounding surface were varied independently. In a subset of neurons, we found pattern-surface interactions that produced similar responses to stimuli across congruent pattern and surface transformations. These interactions produced systematic shifts in curvature tuning of patterns when overlaid on convex and flat surfaces. Our results show that surfaces are factored out of patterns by single neurons, thereby enabling complex perceptual inferences. NEW & NOTEWORTHY We have no difficulty seeing a straight line on a curved piece of paper, but in fact, doing so requires decoupling the shape of the surface from the pattern itself. Here we report a novel form of invariance in the visual cortex: single neurons in monkey inferior temporal cortex respond similarly to congruent transformations of patterns and surfaces, in effect decoupling patterns from the surface on which they are overlaid. PMID:27733595

Cutoff for extensions of massive gravity and bi-gravity

NASA Astrophysics Data System (ADS)

Matas, Andrew

2016-04-01

Recently there has been interest in extending ghost-free massive gravity, bi-gravity, and multi-gravity by including non-standard kinetic terms and matter couplings. We first review recent proposals for this class of extensions, emphasizing how modifications of the kinetic and potential structure of the graviton and modifications of the coupling to matter are related. We then generalize existing no-go arguments in the metric language to the vielbein language in second-order form. We give an ADM argument to show that the most promising extensions to the kinetic term and matter coupling contain a Boulware-Deser ghost. However, as recently emphasized, we may still be able to view these extensions as effective field theories below some cutoff scale. To address this possibility, we show that there is a decoupling limit where a ghost appears for a wide class of matter couplings and kinetic terms. In particular, we show that there is a decoupling limit where the linear effective vielbein matter coupling contains a ghost. Using the insight we gain from this decoupling limit analysis, we place an upper bound on the cutoff for the linear effective vielbein coupling. This result can be generalized to new kinetic interactions in the vielbein language in second-order form. Combined with recent results, this provides a strong uniqueness argument on the form of ghost-free massive gravity, bi-gravity, and multi-gravity.

Crust-mantle mechanical coupling in Eastern Mediterranean and Eastern Turkey

PubMed Central

Sinan Özeren, M.

2012-01-01

Present-day crust-mantle coupling in the Eastern Mediterranean and eastern Turkey is studied using the Global Positioning System (GPS) and seismic anisotropy data. The general trend of the shear wave fast-splitting directions in NE Turkey and Lesser Caucaus align well with the geodetic velocities in an absolute plate motion frame of reference pointing to an effective coupling in this part of the region of weak surface deformation. Farther south, underneath the Bitlis Suture, however, there are significant Pn delays with E-W anisotropy axes indicating significant lateral escape. Meanwhile, the GPS reveals very little surface deformation. This mismatch possibly suggests a decoupling along the suture. In the Aegean, the shear wave anisotropy and the Pn anisotropy directions agree with the extensional component of the right-lateral shear strains except under the Crete Basin and other parts of the southern Aegean Sea. This extensional direction matches perfectly also with the southward pulling force vectors across the Hellenic trench; however, the maximum right-lateral shear directions obtained from the GPS data in the Aegean do not match either of these anisotropies. Seismic anisotropy from Rayleigh waves sampled at 15 s, corresponding to the lower crust, match the maximum right-lateral maximum shear directions from the GPS indicating decoupling between the crust and the mantle. This decoupling most likely results from the lateral variations of the gravitational potential energies and the slab-pull forces. PMID:22592788

Implementation of single-photon quantum routing and decoupling using a nitrogen-vacancy center and a whispering-gallery-mode resonator-waveguide system.

PubMed

Cao, Cong; Duan, Yu-Wen; Chen, Xi; Zhang, Ru; Wang, Tie-Jun; Wang, Chuan

2017-07-24

Quantum router is a key element needed for the construction of future complex quantum networks. However, quantum routing with photons, and its inverse, quantum decoupling, are difficult to implement as photons do not interact, or interact very weakly in nonlinear media. In this paper, we investigate the possibility of implementing photonic quantum routing based on effects in cavity quantum electrodynamics, and present a scheme for single-photon quantum routing controlled by the other photon using a hybrid system consisting of a single nitrogen-vacancy (NV) center coupled with a whispering-gallery-mode resonator-waveguide structure. Different from the cases in which classical information is used to control the path of quantum signals, both the control and signal photons are quantum in our implementation. Compared with the probabilistic quantum routing protocols based on linear optics, our scheme is deterministic and also scalable to multiple photons. We also present a scheme for single-photon quantum decoupling from an initial state with polarization and spatial-mode encoding, which can implement an inverse operation to the quantum routing. We discuss the feasibility of our schemes by considering current or near-future techniques, and show that both the schemes can operate effectively in the bad-cavity regime. We believe that the schemes could be key building blocks for future complex quantum networks and large-scale quantum information processing.

Sliding Mode Control of the X-33 with an Engine Failure

NASA Technical Reports Server (NTRS)

Shtessel, Yuri B.; Hall, Charles E.

2000-01-01

Ascent flight control of the X-3 is performed using two XRS-2200 linear aerospike engines. in addition to aerosurfaces. The baseline control algorithms are PID with gain scheduling. Flight control using an innovative method. Sliding Mode Control. is presented for nominal and engine failed modes of flight. An easy to implement, robust controller. requiring no reconfiguration or gain scheduling is demonstrated through high fidelity flight simulations. The proposed sliding mode controller utilizes a two-loop structure and provides robust. de-coupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of engine failure, bounded external disturbances (wind gusts) and uncertain matrix of inertia. Sliding mode control causes the angular rate and orientation angle tracking error dynamics to be constrained to linear, de-coupled, homogeneous, and vector valued differential equations with desired eigenvalues. Conditions that restrict engine failures to robustness domain of the sliding mode controller are derived. Overall stability of a two-loop flight control system is assessed. Simulation results show that the designed controller provides robust, accurate, de-coupled tracking of the orientation angle command profiles in the presence of external disturbances and vehicle inertia uncertainties, as well as the single engine failed case. The designed robust controller will significantly reduce the time and cost associated with flying new trajectory profiles or orbits, with new payloads, and with modified vehicles

Production of Nitrous Oxide from Nitrite in Stable Type II Methanotrophic Enrichments.

PubMed

Myung, Jaewook; Wang, Zhiyue; Yuan, Tong; Zhang, Ping; Van Nostrand, Joy D; Zhou, Jizhong; Criddle, Craig S

2015-09-15

The coupled aerobic-anoxic nitrous decomposition operation is a new process for wastewater treatment that removes nitrogen from wastewater and recovers energy from the nitrogen in three steps: (1) NH4(+) oxidation to NO2(-), (2) NO2(-) reduction to N2O, and (3) N2O conversion to N2 with energy production. Here, we demonstrate that type II methanotrophic enrichments can mediate step two by coupling oxidation of poly(3-hydroxybutyrate) (P3HB) to NO2(-) reduction. Enrichments grown with NH4(+) and NO2(-) were subject to alternating 48-h aerobic and anoxic periods, in which CH4 and NO2(-) were added together in a "coupled" mode of operation or separately in a "decoupled mode". Community structure was stable in both modes and dominated by Methylocystis. In the coupled mode, production of P3HB and N2O was low. In the decoupled mode, significant P3HB was produced, and oxidation of P3HB drove reduction of NO2(-) to N2O with ∼ 70% conversion for >30 cycles (120 d). In batch tests of wasted cells from the decoupled mode, N2O production rates increased at low O2 or high NO2(-) levels. The results are significant for the development of engineered processes that remove nitrogen from wastewater and for understanding of conditions that favor environmental production of N2O.

Crust-mantle mechanical coupling in Eastern Mediterranean and eastern Turkey.

PubMed

Özeren, M Sinan

2012-05-29

Present-day crust-mantle coupling in the Eastern Mediterranean and eastern Turkey is studied using the Global Positioning System (GPS) and seismic anisotropy data. The general trend of the shear wave fast-splitting directions in NE Turkey and Lesser Caucaus align well with the geodetic velocities in an absolute plate motion frame of reference pointing to an effective coupling in this part of the region of weak surface deformation. Farther south, underneath the Bitlis Suture, however, there are significant Pn delays with E-W anisotropy axes indicating significant lateral escape. Meanwhile, the GPS reveals very little surface deformation. This mismatch possibly suggests a decoupling along the suture. In the Aegean, the shear wave anisotropy and the Pn anisotropy directions agree with the extensional component of the right-lateral shear strains except under the Crete Basin and other parts of the southern Aegean Sea. This extensional direction matches perfectly also with the southward pulling force vectors across the Hellenic trench; however, the maximum right-lateral shear directions obtained from the GPS data in the Aegean do not match either of these anisotropies. Seismic anisotropy from Rayleigh waves sampled at 15 s, corresponding to the lower crust, match the maximum right-lateral maximum shear directions from the GPS indicating decoupling between the crust and the mantle. This decoupling most likely results from the lateral variations of the gravitational potential energies and the slab-pull forces.

Protection of the lung from blast overpressure by stress wave decouplers, buffer plates or sandwich panels.

PubMed

Sedman, Andrew; Hepper, A

2018-03-19

This paper outlines aspects of UK Ministry of Defence's research and development of blast overpressure protection technologies appropriate for use in body armour, with the aim of both propagating new knowledge and updating existing information. Two simple models are introduced not only to focus the description of the mechanism by which the lungs can be protected, but also to provide a bridge between fields of research that may hold the key to further advances in protection technology and related body armour. Protection can be provided to the lungs by decoupling the stress wave transmission into the thorax by managing the blast energy imparted through the protection system. It is proposed that the utility of the existing 'simple decoupler' blast overpressure protection is reviewed in light of recent developments in the treatment of those sustaining both overpressure and fragment injuries. It is anticipated that further advances in protection technology may be generated by those working in other fields on the analogous technologies of 'buffer plates' and 'sandwich panels'. © Crown copyright (2018), Dstl. This material is licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gsi.gov.uk.

Fracture Decoupling of Small Chemical Explosions in Granite and Limestone

NASA Astrophysics Data System (ADS)

Stroujkova, A. F.; Bonner, J. L.; Reinke, R.; Lenox, E. A.

2012-12-01

Reduction of the seismic amplitudes produced by underground explosions due to dissipation in a low-coupling medium poses a significant challenge for nuclear test monitoring. We examined the data from two experiments, which involved conducting explosions in the damage zone created by previous explosions ("repeat shots"). The first experiment was conducted in central New Hampshire in a fluid saturated granodiorite. The experiment involved detonating two 46 kg explosions: one in virgin rock and the other in the fractured rock zone produced by a larger (232 kg) explosion. The second experiment took place near Albuquerque, NM, in dry limestone. In this scenario the second explosion was conducted in the cavity created by the first explosion. Both limestone explosions had yields of 90.5 kg. The reduction of the seismic amplitudes was observed for both repeat shots: in granodiorite the amplitudes were reduced by a factor of 2-3, in limestone by a factor of 3-4 compared to the shots in the undamaged rocks. For the granodiorite repeat shot the decoupling ratios were frequency dependent with stronger amplitude reduction at higher frequencies. In addition, the virgin rock shot produced higher corner frequency and overshoot parameter than the repeat shot. For the limestone shot the decoupling ratios were nearly flat at all frequencies with similar corner frequencies. This observation suggests different mechanisms of energy dissipation for the two experiments.

3-D decoupled inversion of complex conductivity data in the real number domain

NASA Astrophysics Data System (ADS)

Johnson, Timothy C.; Thomle, Jonathan

2018-01-01

Complex conductivity imaging (also called induced polarization imaging or spectral induced polarization imaging when conducted at multiple frequencies) involves estimating the frequency-dependent complex electrical conductivity distribution of the subsurface. The superior diagnostic capabilities provided by complex conductivity spectra have driven advancements in mechanistic understanding of complex conductivity as well as modelling and inversion approaches over the past several decades. In this work, we demonstrate the theory and application for an approach to 3-D modelling and inversion of complex conductivity data in the real number domain. Beginning from first principles, we demonstrate how the equations for the real and imaginary components of the complex potential may be decoupled. This leads to a description of the real and imaginary source current terms, and a corresponding assessment of error arising from an assumption necessary to complete the decoupled modelling. We show that for most earth materials, which exhibit relatively small phases (e.g. less than 0.2 radians) in complex conductivity, these errors become insignificant. For higher phase materials, the errors may be quantified and corrected through an iterative procedure. We demonstrate the accuracy of numerical forward solutions by direct comparison to corresponding analytic solutions. We demonstrate the inversion using both synthetic and field examples with data collected over a waste infiltration trench, at frequencies ranging from 0.5 to 7.5 Hz.

Applications of control theory

NASA Technical Reports Server (NTRS)

Taft, C. K.; Pokoski, J. L.; Murdoch, J. B.; Limbert, D. E.; Alperi, R. W.

1972-01-01

Applications of control theory are considered in the areas of decoupling and wake steering control of submersibles, a method of electrohydraulic conversion with no moving parts, and socio-economic system modelling.

Precise Measurement of Long-Range Heteronuclear Coupling Constants by a Novel Broadband Proton–Proton-Decoupled CPMG-HSQMBC Method

PubMed Central

Timári, István; Illyés, Tünde Z; Adams, Ralph W; Nilsson, Mathias; Szilágyi, László; Morris, Gareth A; Kövér, Katalin E

2015-01-01

A broadband proton–proton-decoupled CPMG-HSQMBC method for the precise and direct measurement of long-range heteronuclear coupling constants is presented. The Zangger–Sterk-based homodecoupling scheme reported herein efficiently removes unwanted proton–proton splittings from the heteronuclear multiplets, so that the desired heteronuclear couplings can be determined simply by measuring frequency differences between singlet maxima in the resulting spectra. The proposed pseudo-1D/2D pulse sequences were tested on nucleotides, a metal complex incorporating P heterocycles, and diglycosyl (di)selenides, as well as on other carbohydrate derivatives, for the extraction of nJ(1H,31P), nJ(1H,77Se), and nJ(1H,13C) values, respectively. PMID:25573660

A piloted simulator study on augmentation systems to improve helicopter flying qualities in terrain flight

NASA Technical Reports Server (NTRS)

Chen, R. T. N.; Talbot, P. D.; Gerdes, R. M.; Dugan, D. C.

1979-01-01

Four basic single-rotor helicopters, one teetering, on articulated, and two hingeless, which were found to have a variety of major deficiencies in a previous fixed-based simulator study, were selected as baseline configurations. The stability and control augmentation systems (SCAS) include simple control augmentation systems to decouple pitch and yaw responses due to collective input and to quicken the pitch and roll control responses; SCAS of rate-command type designed to optimize the sensitivity and damping and to decouple the pitch-roll due to aircraft angular tate; and attitude-command type SCAS. Pilot ratings and commentary are presented as well as performance data related to the task. SCAS control usages and their gain levels associated with specific rotor types are also discussed.

Spectroscopy and imaging with a 4 tesla whole-body MR system.

PubMed

Bomsdorf, H; Helzel, T; Kunz, D; Röschmann, P; Tschendel, O; Wieland, J

1988-06-01

Magnetic resonance (MR) spectroscopy and imaging experiments on humans were performed with a whole-body MR system at a static field of 4 tesla. Spectroscopic studies focussed on 1H, 13C, and 31P. Imaging of humans turned out to be possible, although below the optimum at this field. This holds especially for body imaging, since RF penetration effects and dielectric resonances influence the RF field homogeneity. Excellent volume selective proton spectra of the human cerebrum and cerebellum were obtained using the stimulated echo method. Natural abundance carbon spectra of the human calf were acquired both undecoupled and with narrowband decoupling, resolving the various triglyceride resonances. Broadband decoupling, however, would have violated SAR guidelines. Liver glycogen was detected on natural abundance 13C spectra.

Decoupling the refractive index from the electrical properties of transparent conducting oxides via periodic superlattices

PubMed Central

Caffrey, David; Norton, Emma; Coileáin, Cormac Ó; Smith, Christopher M.; Bulfin, Brendan; Farrell, Leo; Shvets, Igor V.; Fleischer, Karsten

2016-01-01

We demonstrate an alternative approach to tuning the refractive index of materials. Current methodologies for tuning the refractive index of a material often result in undesirable changes to the structural or optoelectronic properties. By artificially layering a transparent conducting oxide with a lower refractive index material the overall film retains a desirable conductivity and mobility while acting optically as an effective medium with a modified refractive index. Calculations indicate that, with our refractive index change of 0.2, a significant reduction of reflective losses could be obtained by the utilisation of these structures in optoelectronic devices. Beyond this, periodic superlattice structures present a solution to decouple physical properties where the underlying electronic interaction is governed by different length scales. PMID:27623228

Decentralized PID controller for TITO systems using characteristic ratio assignment with an experimental application.

PubMed

Hajare, V D; Patre, B M

2015-11-01

This paper presents a decentralized PID controller design method for two input two output (TITO) systems with time delay using characteristic ratio assignment (CRA) method. The ability of CRA method to design controller for desired transient response has been explored for TITO systems. The design methodology uses an ideal decoupler to reduce the interaction. Each decoupled subsystem is reduced to first order plus dead time (FOPDT) model to design independent diagonal controllers. Based on specified overshoot and settling time, the controller parameters are computed using CRA method. To verify performance of the proposed controller, two benchmark simulation examples are presented. To demonstrate applicability of the proposed controller, experimentation is performed on real life interacting coupled tank level system. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Decoupling nonclassical nonlinear behavior of elastic wave types

DOE PAGES

Remillieux, Marcel C.; Guyer, Robert A.; Payan, Cedric; ...

2016-03-01

In this Letter, the tensorial nature of the nonequilibrium dynamics in nonlinear mesoscopic elastic materials is evidenced via multimode resonance experiments. In these experiments the dynamic response, including the spatial variations of velocities and strains, is carefully monitored while the sample is vibrated in a purely longitudinal or a purely torsional mode. By analogy with the fact that such experiments can decouple the elements of the linear elastic tensor, we demonstrate that the parameters quantifying the nonequilibrium dynamics of the material differ substantially for a compressional wave and for a shear wave. As a result, this could lead to furthermore » understanding of the nonlinear mechanical phenomena that arise in natural systems as well as to the design and engineering of nonlinear acoustic metamaterials.« less

Trusted measurement model based on multitenant behaviors.

PubMed

Ning, Zhen-Hu; Shen, Chang-Xiang; Zhao, Yong; Liang, Peng

2014-01-01

With a fast growing pervasive computing, especially cloud computing, the behaviour measurement is at the core and plays a vital role. A new behaviour measurement tailored for Multitenants in cloud computing is needed urgently to fundamentally establish trust relationship. Based on our previous research, we propose an improved trust relationship scheme which captures the world of cloud computing where multitenants share the same physical computing platform. Here, we first present the related work on multitenant behaviour; secondly, we give the scheme of behaviour measurement where decoupling of multitenants is taken into account; thirdly, we explicitly explain our decoupling algorithm for multitenants; fourthly, we introduce a new way of similarity calculation for deviation control, which fits the coupled multitenants under study well; lastly, we design the experiments to test our scheme.

Collective Yu-Shiba-Rusinov states in magnetic clusters at superconducting surfaces

NASA Astrophysics Data System (ADS)

Körber, Simon; Trauzettel, Björn; Kashuba, Oleksiy

2018-05-01

We study the properties of collective Yu-Shiba-Rusinov (YSR) states generated by multiple magnetic adatoms (clusters) placed on the surface of a superconductor. For magnetic clusters with equal distances between their constituents, we demonstrate the formation of effectively spin-unpolarized YSR states with subgap energies independent of the spin configuration of the magnetic impurities. We solve the problem analytically for arbitrary spin structure and analyze both spin-polarized (dispersive energy levels) and spin-unpolarized (pinned energy levels) solutions. While the energies of the spin-polarized solutions can be characterized solely by the net magnetic moment of the cluster, the wave functions of the spin-unpolarized solutions effectively decouple from it. This decoupling makes them stable against thermal fluctuation and detectable in scanning tunneling microscopy experiments.

Extending the electron spin coherence time of atomic hydrogen by dynamical decoupling.

PubMed

Mitrikas, George; Efthimiadou, Eleni K; Kordas, George

2014-02-14

We study the electron spin decoherence of encapsulated atomic hydrogen in octasilsesquioxane cages induced by the (1)H and (29)Si nuclear spin bath. By applying the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence we significantly suppress the low-frequency noise due to nuclear spin flip-flops up to the point where a maximum T2 = 56 μs is observed. Moreover, dynamical decoupling with the CPMG sequence reveals the existence of two other sources of decoherence: first, a classical magnetic field noise imposed by the (1)H nuclear spins of the cage organic substituents, which can be described by a virtual fluctuating magnetic field with the proton Larmor frequency, and second, decoherence due to anisotropic hyperfine coupling between the electron and the inner (29)Si spins of the cage.

Automated AFM for small-scale and large-scale surface profiling in CMP applications

NASA Astrophysics Data System (ADS)

Zandiatashbar, Ardavan; Kim, Byong; Yoo, Young-kook; Lee, Keibock; Jo, Ahjin; Lee, Ju Suk; Cho, Sang-Joon; Park, Sang-il

2018-03-01

As the feature size is shrinking in the foundries, the need for inline high resolution surface profiling with versatile capabilities is increasing. One of the important areas of this need is chemical mechanical planarization (CMP) process. We introduce a new generation of atomic force profiler (AFP) using decoupled scanners design. The system is capable of providing small-scale profiling using XY scanner and large-scale profiling using sliding stage. Decoupled scanners design enables enhanced vision which helps minimizing the positioning error for locations of interest in case of highly polished dies. Non-Contact mode imaging is another feature of interest in this system which is used for surface roughness measurement, automatic defect review, and deep trench measurement. Examples of the measurements performed using the atomic force profiler are demonstrated.

Trusted Measurement Model Based on Multitenant Behaviors

PubMed Central

Ning, Zhen-Hu; Shen, Chang-Xiang; Zhao, Yong; Liang, Peng

2014-01-01

With a fast growing pervasive computing, especially cloud computing, the behaviour measurement is at the core and plays a vital role. A new behaviour measurement tailored for Multitenants in cloud computing is needed urgently to fundamentally establish trust relationship. Based on our previous research, we propose an improved trust relationship scheme which captures the world of cloud computing where multitenants share the same physical computing platform. Here, we first present the related work on multitenant behaviour; secondly, we give the scheme of behaviour measurement where decoupling of multitenants is taken into account; thirdly, we explicitly explain our decoupling algorithm for multitenants; fourthly, we introduce a new way of similarity calculation for deviation control, which fits the coupled multitenants under study well; lastly, we design the experiments to test our scheme. PMID:24987731

Flux Decoupling and Chemical Diffusion in Redox Dynamics in Aluminosilicate Melts and Glasses (Invited)

NASA Astrophysics Data System (ADS)

Cooper, R. F.

2010-12-01

Measurements of redox dynamics in silicate melts and glasses suggest that, for many compositions and for many external environments, the reaction proceeds and is rate-limited by the diffusive flux of divalent-cation network modifiers. Application of ion-backscattering spectrometry either (i) on oxidized or reduced melts (subsequently quenched before analysis) or (ii) on similarly reacted glasses, both of basalt-composition polymerization, demonstrates that the network modifiers move relative to the (first-order-rigid) aluminosilicate network. Thus, the textures associated with such reactions are often surprising, and frequently include metastable or unstable phases and/or spatial compositional differences. This response is only possible if the motion of cations can be decoupled from that of anions. In many cases, decoupling is accomplished by the presence in the melt/glass of transition-metal cations, whose heterovalency creates distortions in the electronic band structure resulting in electronic defects: electron “holes” in the valence band or electrons in the conduction band. (The prevalence of holes or electrons being a function of bulk chemistry and oxygen activity.) These electronic species make the melt/glass a “defect semiconductor.” Because (a) the critical issue in reaction dynamics is the transport coefficient (the product of species mobility and species concentration) and (b) the electronic species are many orders of magnitude more mobile than are the ions, very low concentrations of transition-metal ions are required for flux decoupling. For example, 0.04 at% Fe keeps a magnesium aluminosilicate melt/glass a defect semiconductor down to 800°C [Cook & Cooper, 2000]. Depending on composition, high-temperature melts can see ion species having a high-enough transport coefficient to allow decoupling, e.g., alkali cations in a basaltic melt [e.g., Pommier et al., 2010]. In this presentation, these ideas will be illustrated by examining redox dynamics in basaltic melts [e.g., Burgess et al., 2010; Cooper et al., 2010] and the reaction of magnesium aluminosilicate melts (transition-metal-ion-free and -doped) with liquid bronze (Cu-Sn alloy) [Pettersen et al., 2008], the latter demonstrating the importance of heterovalency in silicon [e.g., Borman et al., 1991] in effecting the reaction dynamics and resultant texture. Borman, V.D. et al. (1991) Phys. Rev. Lett. 67:2387-2390. Burgess, K. et al. (2010) Geochem. Geophys. Geosyst. 11:in press. Cook, G.B., and R.F. Cooper (2000) Am. Mineral. 85:397-406. Cooper, R.F. et al. (2010) Am. Mineral. 95:810-824. Pettersen, C., and R.F. Cooper (2008) J. Non-Crys. Solids 354:3194-3206. Pommier, A. et al. (2010) Geochim. Cosmochim. Acta 74:1653-1671.

HST IMAGING OF DUST STRUCTURES AND STARS IN THE RAM PRESSURE STRIPPED VIRGO SPIRALS NGC 4402 AND NGC 4522: STRIPPED FROM THE OUTSIDE IN WITH DENSE CLOUD DECOUPLING

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

Abramson, A.; Kenney, J.; Crowl, H.

We describe and constrain the origins of interstellar medium (ISM) structures likely created by ongoing intracluster medium (ICM) ram pressure stripping in two Virgo Cluster spirals, NGC 4522 and NGC 4402, using Hubble Space Telescope (HST) BVI images of dust extinction and stars, as well as supplementary H i, H α , and radio continuum images. With a spatial resolution of ∼10 pc in the HST images, this is the highest-resolution study to date of the physical processes that occur during an ICM–ISM ram pressure stripping interaction, ram pressure stripping's effects on the multi-phase, multi-density ISM, and the formation andmore » evolution of ram-pressure-stripped tails. In dust extinction, we view the leading side of NGC 4402 and the trailing side of NGC 4522, and so we see distinct types of features in both. In both galaxies, we identify some regions where dense clouds are decoupling or have decoupled and others where it appears that kiloparsec-sized sections of the ISM are moving coherently. NGC 4522 has experienced stronger, more recent pressure and has the “jellyfish” morphology characteristic of some ram-pressure-stripped galaxies. Its stripped tail extends up from the disk plane in continuous upturns of dust and stars curving up to ∼2 kpc above the disk plane. On the other side of the galaxy, there is a kinematically and morphologically distinct extraplanar arm of young, blue stars and ISM above a mostly stripped portion of the disk, and between it and the disk plane are decoupled dust clouds that have not been completely stripped. The leading side of NGC 4402 contains two kiloparsec-scale linear dust filaments with complex substructure that have partially decoupled from the surrounding ISM. NGC 4402 also contains long dust ridges, suggesting that large parts of the ISM are being pushed out at once. Both galaxies contain long ridges of polarized radio continuum emission indicating the presence of large-scale, ordered magnetic fields. We propose that magnetic fields could bind together gas of different densities, causing nearby gas of different densities to be stripped at the same rate and creating the large, coherent dust ridges and upturns. A number of factors likely play roles in determining what types of structures form as a result of ram pressure, including ram pressure strength and history, the location within the galaxy relative to the leading side, and pre-existing substructure in the ISM that may be bound together by magnetic fields during stripping.« less

Novel insecticides and acaricides

NASA Astrophysics Data System (ADS)

Grapov, Artur F.

1999-08-01

This review outlines the major achievements in design of novel chemical insecticides and acaricides, especially those with non-standard mechanisms of action, viz., neonicotinoids and oxidative phosphorylation decouplers. The bibliography includes 119 references.

Decoupling of stream and vegetation solutes during the late stages of weathering: insights from elemental and Mg isotope trends at the Luquillo Critical Zone Observatory, Puerto Rico

NASA Astrophysics Data System (ADS)

Chapela Lara, M.; Schuessler, J. A.; Buss, H. L.; McDowell, W. H.

2017-12-01

During the evolution of the critical zone, the predominant source of nutrients to the vegetation changes from bedrock weathering to atmospheric inputs and biological recycling. In parallel, the architecture of the critical zone changes with time, promoting a change in water flow regime from near-surface porous flow during early weathering stages to more complex flow regimes modulated by clay-rich regolith during the late stages of weathering. As a consequence of these two concurrent processes, we can expect the predominant sources and pathways of solutes to the streams to also change during critical zone evolution. If this is true, we would observe a decoupling between the solutes used by the vegetation and those that determine the composition of the streams during the late stages of weathering, represented by geomorphically stable tropical settings. To test these hypotheses, we are analyzing the elemental and Mg isotopic composition of regolith and streams at the humid tropical Luquillo Critical Zone Observatory. We aim to trace the relative contributions of the surficial, biologically mediated pathways and the deeper, weathering controlled nutrient pathways. We also investigate the role of lithology on the solute decoupling between the vegetation and the stream, by examining two similar headwater catchments draining two different bedrocks (andesitic volcaniclastic and granitic). Our preliminary elemental and Mg isotope results are consistent with atmospheric inputs in the upper 2 m of regolith in both lithologies and with bedrock weathering at depth. During a short storm event ( 6 h), a headwater stream draining volcaniclastic bedrock showed a large variation in Mg and δ26Mg, correlated with total suspended solids, while another similar headwater granitic stream showed a much narrower variation. A larger stream draining volcaniclastic bedrock showed changes in Mg concentration in response to rain during the same storm event, but did not change in δ26Mg, suggesting the surficial-deep decoupling of solutes we observe in regolith profiles and headwater catchments might be overwhelmed by storage effects at increasing water residence times.

Water-stress-induced breakdown of carbon-water relations: indicators from diurnal FLUXNET patterns

NASA Astrophysics Data System (ADS)

Nelson, Jacob A.; Carvalhais, Nuno; Migliavacca, Mirco; Reichstein, Markus; Jung, Martin

2018-04-01

Understanding of terrestrial carbon and water cycles is currently hampered by an uncertainty in how to capture the large variety of plant responses to drought. In FLUXNET, the global network of CO2 and H2O flux observations, many sites do not uniformly report the ancillary variables needed to study drought response physiology. To this end, we outline two data-driven indicators based on diurnal energy, water, and carbon flux patterns derived directly from the eddy covariance data and based on theorized physiological responses to hydraulic and non-stomatal limitations. Hydraulic limitations (i.e. intra-plant limitations on water movement) are proxied using the relative diurnal centroid (CET*), which measures the degree to which the flux of evapotranspiration (ET) is shifted toward the morning. Non-stomatal limitations (e.g. inhibitions of biochemical reactions, RuBisCO activity, and/or mesophyll conductance) are characterized by the Diurnal Water-Carbon Index (DWCI), which measures the degree of coupling between ET and gross primary productivity (GPP) within each day. As a proof of concept we show the response of the metrics at six European sites during the 2003 heat wave event, showing a varied response of morning shifts and decoupling. Globally, we found indications of hydraulic limitations in the form of significantly high frequencies of morning-shifted days in dry/Mediterranean climates and savanna/evergreen plant functional types (PFTs), whereas high frequencies of decoupling were dominated by dry climates and grassland/savanna PFTs indicating a prevalence of non-stomatal limitations in these ecosystems. Overall, both the diurnal centroid and DWCI were associated with high net radiation and low latent energy typical of drought. Using three water use efficiency (WUE) models, we found the mean differences between expected and observed WUE to be -0.09 to 0.44 µmol mmol-1 and -0.29 to -0.40 µmol mmol-1 for decoupled and morning-shifted days, respectively, compared to mean differences -1.41 to -1.42 µmol mmol-1 in dry conditions, suggesting that morning shifts/hydraulic responses are associated with an increase in WUE, whereas decoupling/non-stomatal limitations are not.

A Geochemical View on the Interplay Between Earth's Mantle and Crust

NASA Astrophysics Data System (ADS)

Chauvel, C.

2017-12-01

Over most of Earth history, oceanic and continental crust was created and destroyed. The formation of both types of crust involves the crystallization and differentiation of magmas producing by mantle melting. Their destruction proceeds by mechanical erosion and weathering above sea level, chemical alteration on the seafloor, and bulk recycling in subduction zones. All these processes enrich of some chemical element and deplete others but each process has its own effect on chemical elements. While the flux of material from mantle to crust is well understood, the return flux is much more complex. In contrast to mantle processes, erosion, weathering, chemical alteration and sedimentary processes strongly decouple elements such as the rare earths and high-field strength elements due to their different solubilities in surface fluids and mineralogical sorting during transport. Soluble elements such as strontium or uranium are quantitatively transported to the ocean by rivers and decoupled from less soluble elements. Over geological time, such decoupling significantly influences the extent to which chemical elements remain at the Earth's surface or find their way back to the mantle through subduction zones. For example, elements like Hf or Nd are retained in heavy minerals on continents whereas U and Sr are transported to the oceans and then in subduction zones to the mantle. The consequence is that different radiogenic isotopic systems give disparate age estimates for the continental crust; e.g, Hf ages could be too old. In subduction zones, chemical elements are also decoupled, due to contrasting behavior during dehydration or melting in subducting slabs. The material sent back into the mantle is generally enriched in non-soluble elements while most fluid-mobile elements return to the crust. This, in turn, affects the relationship between the Rb-Sr, Sm-Nd, Lu-Hf and U-Th-Pb isotopic systems and creates correlations unlike those based on magmatic processes. By quantifying the difference between isotopic arrays created by magmatic processes vs. surface and subduction processes, we can determine how crust recycling creates isotopic heterogeneities in the mantle.

Evidence of weak land-atmosphere coupling under varying bare soil conditions: Are fully coupled Darcy/Navier-Stokes models necessary for simulating soil moisture dynamics?

NASA Astrophysics Data System (ADS)

Illangasekare, T. H.; Trautz, A. C.; Howington, S. E.; Cihan, A.

2017-12-01

It is a well-established fact that the land and atmosphere form a continuum in which the individual domains are coupled by heat and mass transfer processes such as bare-soil evaporation. Soil moisture dynamics can be simulated at the representative elementary volume (REV) scale using decoupled and fully coupled Darcy/Navier-Stokes models. Decoupled modeling is an asynchronous approach in which flow and transport in the soil and atmosphere is simulated independently; the two domains are coupled out of time-step via prescribed flux parameterizations. Fully coupled modeling in contrast, solves the governing equations for flow and transport in both domains simultaneously with the use of coupling interface boundary conditions. This latter approach, while being able to provide real-time two-dimensional feedbacks, is considerably more complex and computationally intensive. In this study, we investigate whether fully coupled models are necessary, or if the simpler decoupled models can sufficiently capture soil moisture dynamics under varying land preparations. A series of intermediate-scale physical and numerical experiments were conducted in which soil moisture distributions and evaporation estimates were monitored at high spatiotemporal resolutions for different heterogeneous packing and soil roughness scenarios. All experimentation was conducted at the newly developed Center for Experimental Study of Subsurface Environmental Processes (CESEP) wind tunnel-porous media user test-facility at the Colorado School of. Near-surface atmospheric measurements made during the experiments demonstrate that the land-atmosphere coupling was relatively weak and insensitive to the applied edaphic and surface conditions. Simulations with a decoupled multiphase heat and mass transfer model similarly show little sensitivity to local variations in atmospheric forcing; a single, simple flux parameterization can sufficiently capture the soil moisture dynamics (evaporation and redistribution) as long as the subsurface conditions (i.e., heterogeneity) are properly described. These findings suggest that significant improvements to simulations results should not be expected if fully coupled modeling were adopted in scenarios of weak land-atmosphere coupling in the context of bare soil evaporation.

Modularity of a leaf moth-wing pattern and a versatile characteristic of the wing-pattern ground plan

PubMed Central

2013-01-01

Background One of the most intriguing questions in evolutionary developmental biology is how an insect acquires a mimicry pattern within its body parts. A striking example of pattern mimicry is found in the pattern diversity of moth and butterfly wings, which is thought to evolve from preexisting elements illustrated by the nymphalid ground plan (NGP). Previous studies demonstrated that individuality of the NGP facilitates the decoupling of associated common elements, leading to divergence. In contrast, recent studies on the concept of modularity have argued the importance of a combination of coupling and decoupling of the constituent elements. Here, we examine the modularity of a mimicry wing pattern in a moth and explore an evolvable characteristic of the NGP. Results This study examined the wings of the noctuid moth Oraesia excavata, which closely resemble leaves with a leaf venation pattern. Based on a comparative morphological procedure, we found that this leaf pattern was formed by the NGP common elements. Using geometric morphometrics combined with network analysis, we found that each of the modules in the leaf pattern integrates the constituent components of the leaf venation pattern (i.e., the main and lateral veins). Moreover, the detected modules were established by coupling different common elements and decoupling even a single element into different modules. The modules of the O. excavata wing pattern were associated with leaf mimicry, not with the individuality of the NGP common elements. For comparison, we also investigated the modularity of a nonmimetic pattern in the noctuid moth Thyas juno. Quantitative analysis demonstrated that the modules of the T. juno wing pattern regularly corresponded to the individuality of the NGP common elements, unlike those in the O. excavata wing pattern. Conclusions This study provides the first evidence for modularity in a leaf mimicry pattern. The results suggest that the evolution of this pattern involves coupling and decoupling processes to originate these modules, free from the individuality of the NGP system. We propose that this evolution has been facilitated by a versatile characteristic of the NGP, allowing the association of freely modifiable subordinate common elements to make modules. PMID:23890367

Selection of an endogenous 2,3-butanediol pathway in Escherichia coli by fermentative redox balance.

PubMed

Liang, Keming; Shen, Claire R

2017-01-01

Fermentative redox balance has long been utilized as a metabolic evolution platform to improve efficiency of NADH-dependent pathways. However, such system relies on the complete recycling of NADH and may become limited when the target pathway results in excess NADH stoichiometrically. In this study, endogenous capability of Escherichia coli for 2,3-butanediol (2,3-BD) synthesis was explored using the anaerobic selection platform based on redox balance. To address the issue of NADH excess associated with the 2,3-BD pathway, we devised a substrate-decoupled system where a pathway intermediate is externally supplied in addition to the carbon source to decouple NADH recycling ratio from the intrinsic pathway stoichiometry. In this case, feeding of the 2,3-BD precursor acetoin effectively restored anaerobic growth of the mixed-acid fermentation mutant that remained otherwise inhibited even in the presence of a functional 2,3-BD pathway. Using established 2,3-BD dehydrogenases as model enzyme, we verified that the redox-based selection system is responsive to NADPH-dependent reactions but with lower sensitivity. Based on this substrate-decoupled selection scheme, we successfully identified the glycerol/1,2-propanediol dehydrogenase (Ec-GldA) as the major enzyme responsible for the acetoin reducing activity (k cat /K m ≈0.4mM -1 s -1 ) observed in E. coli. Significant shift of 2,3-BD configuration upon withdrawal of the heterologous acetolactate decarboxylase revealed that the endogenous synthesis of acetoin occurs via diacetyl. Among the predicted diacetyl reductase in E. coli, Ec-UcpA displayed the most significant activity towards diacetyl reduction into acetoin (V max ≈6U/mg). The final strain demonstrated a meso-2,3-BD production titer of 3g/L without introduction of foreign genes. The substrate-decoupled selection system allows redox balance regardless of the pathway stoichiometry thus enables segmented optimization of different reductive pathways through enzyme bioprospecting and metabolic evolution. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

A Course in... Multivariable Control Methods.

ERIC Educational Resources Information Center

Deshpande, Pradeep B.

1988-01-01

Describes an engineering course for graduate study in process control. Lists four major topics: interaction analysis, multiloop controller design, decoupling, and multivariable control strategies. Suggests a course outline and gives information about each topic. (MVL)

Decoupling analysis of a novel bearingless flux-switching permanent magnet motor

NASA Astrophysics Data System (ADS)

Zhao, Chenyin; Zhu, Huangqiu; Qin, Yuemei

2017-05-01

In this paper, a novel 12/10 stator/rotor pole bearingless flux-switching permanent magnet (BFSPM) motor is proposed to overcome the drawbacks of rotor permanent magnet type bearingless motors. The basic motor configuration, including motor configuration and winding configuration, is introduced firstly. Then, based on the principle of reverse direction magnetization for symmetrical rotor teeth, the radial suspension forces generation principle is analyzed in detail. Finally, decoupling performances between suspension force windings and torque windings are investigated. The results show that the proposed BFSPM not only ensures the merits of high torque output capability compared with conventional 12/10 stator/rotor pole FSPM motor, but also achieves stable radial suspension forces which have little mutual effect with torque. The validity of the proposed structure has been verified by finite element analysis (FEA).

Simulation of disturbance rejection control of half-car active suspension system using active disturbance rejection control with decoupling transformation

NASA Astrophysics Data System (ADS)

Hasbullah, Faried; Faris, Waleed F.

2017-12-01

In recent years, Active Disturbance Rejection Control (ADRC) has become a popular control alternative due to its easy applicability and robustness to varying processes. In this article, ADRC with input decoupling transformation (ADRC-IDT) is proposed to improve ride comfort of a vehicle with an active suspension system using half-car model. The ride performance of the ADRC-IDT is evaluated and compared with decentralized ADRC control as well as the passive system. Simulation results show that both ADRC and ADRC-IDT manage to appreciably reduce body accelerations and able to cope well with varying conditions typically encountered in an active suspension system. Also, it is sufficient to control only the body motions with both active controllers to improve ride comfort while maintaining good road holding and small suspension working space.

Decoupled CFD-based optimization of efficiency and cavitation performance of a double-suction pump

NASA Astrophysics Data System (ADS)

Škerlavaj, A.; Morgut, M.; Jošt, D.; Nobile, E.

2017-04-01

In this study the impeller geometry of a double-suction pump ensuring the best performances in terms of hydraulic efficiency and reluctance of cavitation is determined using an optimization strategy, which was driven by means of the modeFRONTIER optimization platform. The different impeller shapes (designs) are modified according to the optimization parameters and tested with a computational fluid dynamics (CFD) software, namely ANSYS CFX. The simulations are performed using a decoupled approach, where only the impeller domain region is numerically investigated for computational convenience. The flow losses in the volute are estimated on the base of the velocity distribution at the impeller outlet. The best designs are then validated considering the computationally more expensive full geometry CFD model. The overall results show that the proposed approach is suitable for quick impeller shape optimization.

Automated data processing of { 1H-decoupled} 13C MR spectra acquired from human brain in vivo

NASA Astrophysics Data System (ADS)

Shic, Frederick; Ross, Brian

2003-06-01

In clinical 13C infusion studies, broadband excitation of 200 ppm of the human brain yields 13C MR spectra with a time resolution of 2-5 min and generates up to 2000 metabolite peaks over 2 h. We describe a fast, automated, observer-independent technique for processing { 1H-decoupled} 13C spectra. Quantified 13C spectroscopic signals, before and after the administration of [1- 13C]glucose and/or [1- 13C]acetate in human subjects are determined. Stepwise improvements of data processing are illustrated by examples of normal and pathological results. Variation in analysis of individual 13C resonances ranged between 2 and 14%. Using this method it is possible to reliably identify subtle metabolic effects of brain disease including Alzheimer's disease and epilepsy.

Remote pivot decoupler pylon: Wing/store flutter suppressor

NASA Technical Reports Server (NTRS)

Hassler, J. M., Jr. (Inventor)

1986-01-01

A device for suspending a store from an aerodynamic support surface, such an an aircraft wing, and more specifically, for improving upon singlet pivot decoupler pylons by reducing both frequency of active store, alignment, and alignment system space and power requirements. Two links suspend a lower pylon/rack section and releasable attached store from an upper pylon section mounted under the wing. The links allow the lower pylon section to rotate in pitch about a remote pivot point. A leaf spring connected between the lower section and electrical alignment system servomechanism provides pitch alignment of the lower section/store combination. The servomechanism utilizes an electric servomotor to drive the gear train and reversibly move the leaf spring, thereby maintaining the pitch attitude of the store within acceptable limits. The damper strokes when the lower section rotates to damp large oscillations of store.

Gravitational decoupled anisotropies in compact stars

NASA Astrophysics Data System (ADS)

Gabbanelli, Luciano; Rincón, Ángel; Rubio, Carlos

2018-05-01

Simple generic extensions of isotropic Durgapal-Fuloria stars to the anisotropic domain are presented. These anisotropic solutions are obtained by guided minimal deformations over the isotropic system. When the anisotropic sector interacts in a purely gravitational manner, the conditions to decouple both sectors by means of the minimal geometric deformation approach are satisfied. Hence the anisotropic field equations are isolated resulting a more treatable set. The simplicity of the equations allows one to manipulate the anisotropies that can be implemented in a systematic way to obtain different realistic models for anisotropic configurations. Later on, observational effects of such anisotropies when measuring the surface redshift are discussed. To conclude, the consistency of the application of the method over the obtained anisotropic configurations is shown. In this manner, different anisotropic sectors can be isolated of each other and modeled in a simple and systematic way.

Calculating intensities using effective Hamiltonians in terms of Coriolis-adapted normal modes.

PubMed

Karthikeyan, S; Krishnan, Mangala Sunder; Carrington, Tucker

2005-01-15

The calculation of rovibrational transition energies and intensities is often hampered by the fact that vibrational states are strongly coupled by Coriolis terms. Because it invalidates the use of perturbation theory for the purpose of decoupling these states, the coupling makes it difficult to analyze spectra and to extract information from them. One either ignores the problem and hopes that the effect of the coupling is minimal or one is forced to diagonalize effective rovibrational matrices (rather than diagonalizing effective rotational matrices). In this paper we apply a procedure, based on a quantum mechanical canonical transformation for deriving decoupled effective rotational Hamiltonians. In previous papers we have used this technique to compute energy levels. In this paper we show that it can also be applied to determine intensities. The ideas are applied to the ethylene molecule.

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, D.W.; Lange, A.C.

1995-05-23

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

Supersymmetric Gauge Theories with Decoupled Operators and Chiral Ring Stability

NASA Astrophysics Data System (ADS)

Benvenuti, Sergio; Giacomelli, Simone

2017-12-01

We propose a general way to complete supersymmetric theories with operators below the unitarity bound, adding gauge-singlet fields that enforce the decoupling of such operators. This makes it possible to perform all usual computations, and to compactify on a circle. We concentrate on a duality between an N =1 SU(2) gauge theory and the N =2 A3 Argyres-Douglas theory, mapping the moduli space and chiral ring of the completed N =1 theory to those of the A3 model. We reduce the completed gauge theory to 3D, finding a 3D duality with N =4 supersymmetric QED (SQED) with two flavors. The naive dimensional reduction is instead N =2 SQED. Crucial is a concept of chiral ring stability, which modifies the superpotential and allows for a 3D emergent global symmetry.

Importance of acoustic shielding in sonochemistry.

PubMed

van Iersel, Maikel M; Benes, Nieck E; Keurentjes, Jos T F

2008-04-01

It is well known that sonochemistry is less efficient at high acoustic intensities. Many authors have attributed this effect to decoupling losses and shielding of the acoustic wave. In this study we investigate both phenomena for a 20 kHz ultrasound field with an intensity ranging from 40 to 150 W/cm2. Visualization of the bubble cloud has demonstrated that the void fraction below the ultrasound horn increases more than proportional with increasing power input. Nevertheless, the energy coupling between the horn and the liquid remains constant; this implies that decoupling losses are not reinforced for larger bubble clouds. On the contrary, microphone measurements have shown that due to the larger bubble cloud a substantial part of the supplied energy is lost at high power inputs. In striving towards more efficient sonochemistry, reduction of shielding appears as one of the major challenges.

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1995-01-01

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Decoupling of the Leading Order DGLAP Evolution Equation with Spin Dependent Structure Functions

NASA Astrophysics Data System (ADS)

Azadbakht, F. Teimoury; Boroun, G. R.

2018-02-01

We propose an analytical solution for DGLAP evolution equations with polarized splitting functions at the Leading Order (LO) approximation based on the Laplace transform method. It is shown that the DGLAP evolution equations can be decoupled completely into two second order differential equations which then are solved analytically by using the initial conditions δ FS(x,Q2)=F[partial δ FS0(x), δ FS0(x)] and {δ G}(x,Q2)=G[partial δ G0(x), δ G0(x)]. We used this method to obtain the polarized structure function of the proton as well as the polarized gluon distribution function inside the proton and compared the numerical results with experimental data of COMPASS, HERMES, and AAC'08 Collaborations. It was found that there is a good agreement between our predictions and the experiments.

Distributed model predictive control for constrained nonlinear systems with decoupled local dynamics.

PubMed

Zhao, Meng; Ding, Baocang

2015-03-01

This paper considers the distributed model predictive control (MPC) of nonlinear large-scale systems with dynamically decoupled subsystems. According to the coupled state in the overall cost function of centralized MPC, the neighbors are confirmed and fixed for each subsystem, and the overall objective function is disassembled into each local optimization. In order to guarantee the closed-loop stability of distributed MPC algorithm, the overall compatibility constraint for centralized MPC algorithm is decomposed into each local controller. The communication between each subsystem and its neighbors is relatively low, only the current states before optimization and the optimized input variables after optimization are being transferred. For each local controller, the quasi-infinite horizon MPC algorithm is adopted, and the global closed-loop system is proven to be exponentially stable. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Scaling laws and bulk-boundary decoupling in heat flow.

PubMed

del Pozo, Jesús J; Garrido, Pedro L; Hurtado, Pablo I

2015-03-01

When driven out of equilibrium by a temperature gradient, fluids respond by developing a nontrivial, inhomogeneous structure according to the governing macroscopic laws. Here we show that such structure obeys strikingly simple scaling laws arbitrarily far from equilibrium, provided that both macroscopic local equilibrium and Fourier's law hold. Extensive simulations of hard disk fluids confirm the scaling laws even under strong temperature gradients, implying that Fourier's law remains valid in this highly nonlinear regime, with putative corrections absorbed into a nonlinear conductivity functional. In addition, our results show that the scaling laws are robust in the presence of strong finite-size effects, hinting at a subtle bulk-boundary decoupling mechanism which enforces the macroscopic laws on the bulk of the finite-sized fluid. This allows one to measure the marginal anomaly of the heat conductivity predicted for hard disks.

Rheological decoupling at the Moho and implication to Venusian tectonics.

PubMed

Azuma, Shintaro; Katayama, Ikuo; Nakakuki, Tomoeki

2014-03-18

Plate tectonics is largely responsible for material and heat circulation in Earth, but for unknown reasons it does not exist on Venus. The strength of planetary materials is a key control on plate tectonics because physical properties, such as temperature, pressure, stress, and chemical composition, result in strong rheological layering and convection in planetary interiors. Our deformation experiments show that crustal plagioclase is much weaker than mantle olivine at conditions corresponding to the Moho in Venus. Consequently, this strength contrast may produce a mechanical decoupling between the Venusian crust and interior mantle convection. One-dimensional numerical modeling using our experimental data confirms that this large strength contrast at the Moho impedes the surface motion of the Venusian crust and, as such, is an important factor in explaining the absence of plate tectonics on Venus.

Rheological decoupling at the Moho and implication to Venusian tectonics

PubMed Central

Azuma, Shintaro; Katayama, Ikuo; Nakakuki, Tomoeki

2014-01-01

Plate tectonics is largely responsible for material and heat circulation in Earth, but for unknown reasons it does not exist on Venus. The strength of planetary materials is a key control on plate tectonics because physical properties, such as temperature, pressure, stress, and chemical composition, result in strong rheological layering and convection in planetary interiors. Our deformation experiments show that crustal plagioclase is much weaker than mantle olivine at conditions corresponding to the Moho in Venus. Consequently, this strength contrast may produce a mechanical decoupling between the Venusian crust and interior mantle convection. One-dimensional numerical modeling using our experimental data confirms that this large strength contrast at the Moho impedes the surface motion of the Venusian crust and, as such, is an important factor in explaining the absence of plate tectonics on Venus. PMID:24638113

Artificial electron acceptors decouple archaeal methane oxidation from sulfate reduction.

PubMed

Scheller, Silvan; Yu, Hang; Chadwick, Grayson L; McGlynn, Shawn E; Orphan, Victoria J

2016-02-12

The oxidation of methane with sulfate is an important microbial metabolism in the global carbon cycle. In marine methane seeps, this process is mediated by consortia of anaerobic methanotrophic archaea (ANME) that live in syntrophy with sulfate-reducing bacteria (SRB). The underlying interdependencies within this uncultured symbiotic partnership are poorly understood. We used a combination of rate measurements and single-cell stable isotope probing to demonstrate that ANME in deep-sea sediments can be catabolically and anabolically decoupled from their syntrophic SRB partners using soluble artificial oxidants. The ANME still sustain high rates of methane oxidation in the absence of sulfate as the terminal oxidant, lending support to the hypothesis that interspecies extracellular electron transfer is the syntrophic mechanism for the anaerobic oxidation of methane. Copyright © 2016, American Association for the Advancement of Science.

Effects of heavy sea quarks at low energies.

PubMed

Bruno, Mattia; Finkenrath, Jacob; Knechtli, Francesco; Leder, Björn; Sommer, Rainer

2015-03-13

We present a factorization formula for the dependence of light hadron masses and low energy hadronic scales on the mass M of a heavy quark: apart from an overall mass-independent factor Q, ratios such as r_{0}(M)/r_{0}(0) are computable in perturbation theory at large M. The perturbation theory part is stable concerning different loop orders. Our nonperturbative Monte Carlo results obtained in a model calculation, where a doublet of heavy quarks is decoupled, match quantitatively to the perturbative prediction. Upon taking ratios of different hadronic scales at the same mass, the perturbative function drops out and the ratios are given by the decoupled theory up to M^{-2} corrections. We verify-in the continuum limit-that the sea quark effects of quarks with masses around the charm mass are very small in such ratios.

Conductivity-Relaxation Relations in Nanocomposite Polymer Electrolytes Containing Ionic Liquid.

PubMed

Shojaatalhosseini, Mansoureh; Elamin, Khalid; Swenson, Jan

2017-10-19

In this study, we have used nanocomposite polymer electrolytes, consisting of poly(ethylene oxide) (PEO), δ-Al 2 O 3 nanoparticles, and lithium bis(trifluoromethanesolfonyl)imide (LiTFSI) salt (with 4 wt % δ-Al 2 O 3 and PEO:Li ratios of 16:1 and 8:1), and added different amounts of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesolfonyl)imide (BMITFSI). The aim was to elucidate whether the ionic liquid is able to dissociate the Li-ions from the ether oxygens and thereby decouple the ionic conductivity from the segmental polymer dynamics. The results from DSC and dielectric spectroscopy show that the ionic liquid speeds up both the segmental polymer dynamics and the motion of the Li + ions. However, a close comparison between the structural (α) relaxation process, given by the segmental polymer dynamics, and the ionic conductivity shows that the motion of the Li + ions decouples from the segmental polymer dynamics at higher concentrations of the ionic liquid (≥20 wt %) and instead becomes more related to the viscosity of the ionic liquid. This decoupling increases with decreasing temperature. In addition to the structural α-relaxation, two more local relaxation processes, denoted β and γ, are observed. The β-relaxation becomes slightly faster at the highest concentration of the ionic liquid (at least for the lower salt concentration), whereas the γ-relaxation is unaffected by the ionic liquid, over the whole concentration range 0-40 wt %.

Design and Analysis of a Novel Fully Decoupled Tri-axis Linear Vibratory Gyroscope with Matched Modes.

PubMed

Xia, Dunzhu; Kong, Lun; Gao, Haiyu

2015-07-13

We present in this paper a novel fully decoupled silicon micromachined tri-axis linear vibratory gyroscope. The proposed gyroscope structure is highly symmetrical and can be limited to an area of about 8.5 mm × 8.5 mm. It can differentially detect three axes' angular velocities at the same time. By elaborately arranging different beams, anchors and sensing frames, the drive and sense modes are fully decoupled from each other. Moreover, the quadrature error correction and frequency tuning functions are taken into consideration in the structure design for all the sense modes. Since there exists an unwanted in-plane rotational mode, theoretical analysis is implemented to eliminate it. To accelerate the mode matching process, the particle swam optimization (PSO) algorithm is adopted and a frequency split of 149 Hz is first achieved by this method. Then, after two steps of manual adjustment of the springs' dimensions, the frequency gap is further decreased to 3 Hz. With the help of the finite element method (FEM) software ANSYS, the natural frequencies of drive, yaw, and pitch/roll modes are found to be 14,017 Hz, 14,018 Hz and 14,020 Hz, respectively. The cross-axis effect and scale factor of each mode are also simulated. All the simulation results are in good accordance with the theoretical analysis, which means the design is effective and worthy of further investigation on the integration of tri-axis accelerometers on the same single chip to form an inertial measurement unit.

Decoupling of mass transport mechanisms in the stagewise swelling of multiple emulsions.

PubMed

Bahtz, Jana; Gunes, Deniz Z; Hughes, Eric; Pokorny, Lea; Riesch, Francesca; Syrbe, Axel; Fischer, Peter; Windhab, Erich J

2015-05-19

This contribution reports on the mass transport kinetics of osmotically imbalanced water-in-oil-in-water (W1/O/W2) emulsions. Although frequently studied, the control of mass transport in W1/O/W2 emulsions is still challenging. We describe a microfluidics-based method to systematically investigate the impact of various parameters, such as osmotic pressure gradient, oil phase viscosity, and temperature, on the mass transport. Combined with optical microscopy analyses, we are able to identify and decouple the various mechanisms, which control the dynamic droplet size of osmotically imbalanced W1/O/W2 emulsions. So, swelling kinetics curves with a very high accuracy are generated, giving a basis for quantifying the kinetic aspects of transport. Two sequential swelling stages, i.e., a lag stage and an osmotically dominated stage, with different mass transport mechanisms are identified. The determination and interpretation of the different stages are the prerequisite to control and trigger the swelling process. We show evidence that both mass transport mechanisms can be decoupled from each other. Rapid osmotically driven mass transport only takes place in a second stage induced by structural changes of the oil phase in a lag stage, which allow an osmotic exchange between both water phases. Such structural changes are strongly facilitated by spontaneous water-in-oil emulsification. The duration of the lag stage is pressure-independent but significantly influenced by the oil phase viscosity and temperature.

Oxidation of [U-13 C]glucose in the human brain at 7T under steady state conditions.

PubMed

Cheshkov, Sergey; Dimitrov, Ivan E; Jakkamsetti, Vikram; Good, Levi; Kelly, Dorothy; Rajasekaran, Karthik; DeBerardinis, Ralph J; Pascual, Juan M; Sherry, A Dean; Malloy, Craig R

2017-12-01

Disorders of brain energy metabolism and neurotransmitter recycling have been implicated in multiple neurological conditions. 13 C magnetic resonance spectroscopy ( 13 C MRS) during intravenous administration of 13 C-labeled compounds has been used to measure turnover rates of brain metabolites. This approach, however, requires prolonged infusion inside the magnet. Proton decoupling is typically required but may be difficult to implement with standard equipment. We examined an alternative approach to monitor glucose metabolism in the human brain. 13 C-enriched glucose was infused in healthy subjects outside the magnet to a steady-state level of 13 C enrichment. Subsequently, the subjects were scanned at 7T for 60 min without 1 H decoupling. Metabolic modeling was used to calculate anaplerosis. Biomarkers of energy metabolism and anaplerosis were detected. The glutamate C5 doublet provided information about glucose-derived acetyl-coenzyme A flux into the tricarboxylic acid (TCA) cycle via pyruvate dehydrogenase, and the bicarbonate signal reflected overall TCA cycle activity. The glutamate C1/C5 ratio is sensitive to anaplerosis. Brain 13 C MRS at 7T provides information about glucose oxidation and anaplerosis without the need of prolonged 13 C infusions inside the scanner and without technical challenges of 1 H decoupling, making it a feasible approach for clinical research. Magn Reson Med 78:2065-2071, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

A molecular dynamics examination of the relationship between self-diffusion and viscosity in liquid metals.

PubMed

Lü, Yongjun; Cheng, Hao; Chen, Min

2012-06-07

The self-diffusion coefficients D and the viscosities η of elemental Ni, Cu, and Ni-Si alloys have been calculated over a wide temperature range by molecular dynamics simulations. For elemental Ni and Cu, Arrhenius-law variations of D and η with temperature dominate. The temperature dependence of Dη can be approximated by a linear relation, whereas the Stokes-Einstein relation is violated. The calculations of D and η are extended to the regions close to the crystallization of Ni(95)Si(5), Ni(90)Si(10), and the glass transitions of Ni(80)Si(20) and Ni(75)Si(25). The results show that both D and η strongly deviate from the Arrhenius law in the vicinity of phase transitions, exhibiting a power-law divergence. We find a decoupling of diffusion and viscous flow just above the crystallization of Ni(95)Si(5) and Ni(90)Si(10). For the two glass-forming alloys, Ni(80)Si(20) and Ni(75)Si(25), the relation Dη = const is obeyed as the glass transition is approached, indicating a dynamic coupling as predicted by the mode-coupling theory. This coupling is enhanced with increasing Si composition and at 25%, Si spans a wide temperature range through the melting point. The decoupling is found to be related to the distribution of local ordered structure in the melts. The power-law governing the growth of solid-like clusters prior to crystallization creates a dynamic heterogeneity responsible for decoupling.

A molecular dynamics examination of the relationship between self-diffusion and viscosity in liquid metals

NASA Astrophysics Data System (ADS)

Lü, Yongjun; Cheng, Hao; Chen, Min

2012-06-01

The self-diffusion coefficients D and the viscosities η of elemental Ni, Cu, and Ni-Si alloys have been calculated over a wide temperature range by molecular dynamics simulations. For elemental Ni and Cu, Arrhenius-law variations of D and η with temperature dominate. The temperature dependence of Dη can be approximated by a linear relation, whereas the Stokes-Einstein relation is violated. The calculations of D and η are extended to the regions close to the crystallization of Ni95Si5, Ni90Si10, and the glass transitions of Ni80Si20 and Ni75Si25. The results show that both D and η strongly deviate from the Arrhenius law in the vicinity of phase transitions, exhibiting a power-law divergence. We find a decoupling of diffusion and viscous flow just above the crystallization of Ni95Si5 and Ni90Si10. For the two glass-forming alloys, Ni80Si20 and Ni75Si25, the relation Dη = const is obeyed as the glass transition is approached, indicating a dynamic coupling as predicted by the mode-coupling theory. This coupling is enhanced with increasing Si composition and at 25%, Si spans a wide temperature range through the melting point. The decoupling is found to be related to the distribution of local ordered structure in the melts. The power-law governing the growth of solid-like clusters prior to crystallization creates a dynamic heterogeneity responsible for decoupling.

Fornix lesions decouple the induction of hippocampal arc transcription from behavior but not plasticity.

PubMed

Fletcher, Bonnie R; Calhoun, Michael E; Rapp, Peter R; Shapiro, Matthew L

2006-02-01

The immediate-early gene (IEG) Arc is transcribed after behavioral and physiological treatments that induce synaptic plasticity and is implicated in memory consolidation. The relative contributions of neuronal activity and learning-related plasticity to the behavioral induction of Arc remain to be defined. To differentiate the contributions of each, we assessed the induction of Arc transcription in rats with fornix lesions that impair hippocampal learning yet leave cortical connectivity and neuronal firing essentially intact. Arc expression was assessed after exploration of novel environments and performance of a novel water maze task during which normal rats learned the spatial location of an escape platform. During the same task, rats with fornix lesions learned to approach a visible platform but did not learn its spatial location. Rats with fornix lesions had normal baseline levels of hippocampal Arc mRNA, but unlike normal rats, expression was not increased in response to water maze training. The integrity of signaling pathways controlling Arc expression was demonstrated by stimulation of the medial perforant path, which induced normal synaptic potentiation and Arc in rats with fornix lesions. Together, the results demonstrate that Arc induction can be decoupled from behavior and is more likely to indicate the engagement of synaptic plasticity mechanisms than synaptic or neuronal activity per se. The results further imply that fornix lesions may impair memory in part by decoupling neuronal activity from signaling pathways required for long-lasting hippocampal synaptic plasticity.

Decoupling energy and power

NASA Astrophysics Data System (ADS)

Grattieri, Matteo; Minteer, Shelley D.

2018-01-01

Biological photovoltaic devices (BPVs) use photosynthetic microorganisms to produce electricity, but low photocurrent generation impedes their application. Now, a micro-scale flow-based BPV system is reported with power density outputs similar to that of large-scale biofuels.

Diplexer switch

NASA Technical Reports Server (NTRS)

Grauling, C. H., Jr.; Parker, T. W.

1977-01-01

Switch achieves high isolation and continuous input/output matching by using resonant coupling structure of diplexer. Additionally, dc bias network used to control switch is decoupled from RF input and output lines. Voltage transients in external circuits are thus minimized.

Effects of counterion size and backbone rigidity on the dynamics of ionic polymer melts and glasses

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

Fu, Yao; Bocharova, Vera; Ma, Mengze

Backbone rigidity, counterion size and the static dielectric constant affect the glass transition temperature, segmental relaxation time and decoupling between counterion and segmental dynamics in significant manners.

Backlash compensator mechanism

DOEpatents

Chrislock, Jerry L.

1979-01-01

Mechanism which compensates for backlash error in a lead screw position indicator by decoupling the indicator shaft from the lead screw when reversing rotation. The position indicator then displays correct information regardless of the direction of rotation of the lead screw.

Control of hierarchical polymer mechanics with bioinspired metal-coordination dynamics

PubMed Central

Grindy, Scott C.; Learsch, Robert; Mozhdehi, Davoud; Cheng, Jing; Barrett, Devin G.; Guan, Zhibin; Messersmith, Phillip B.; Holten-Andersen, Niels

2015-01-01

In conventional polymer materials, mechanical performance is traditionally engineered via material structure, using motifs such as polymer molecular weight, polymer branching, or copolymer-block design1. Here, by means of a model system of 4-arm poly(ethylene glycol) hydrogels crosslinked with multiple, kinetically distinct dynamic metal-ligand coordinate complexes, we show that polymer materials with decoupled spatial structure and mechanical performance can be designed. By tuning the relative concentration of two types of metal-ligand crosslinks, we demonstrate control over the material’s mechanical hierarchy of energy-dissipating modes under dynamic mechanical loading, and therefore the ability to engineer a priori the viscoelastic properties of these materials by controlling the types of crosslinks rather than by modifying the polymer itself. This strategy to decouple material mechanics from structure may inform the design of soft materials for use in complex mechanical environments. PMID:26322715

Edge states in gated bilayer-monolayer graphene ribbons and bilayer domain walls

NASA Astrophysics Data System (ADS)

Mirzakhani, M.; Zarenia, M.; Peeters, F. M.

2018-05-01

Using the effective continuum model, the electron energy spectrum of gated bilayer graphene with a step-like region of decoupled graphene layers at the edge of the sample is studied. Different types of coupled-decoupled interfaces are considered, i.e., zigzag (ZZ) and armchair junctions, which result in significant different propagating states. Two non-valley-polarized conducting edge states are observed for ZZ type, which are mainly located around the ZZ-ended graphene layers. Additionally, we investigated both BA-BA and BA-AB domain walls in the gated bilayer graphene within the continuum approximation. Unlike the BA-BA domain wall, which exhibits gapped insulating behaviour, the domain walls surrounded by different stackings of bilayer regions feature valley-polarized edge states. Our findings are consistent with other theoretical calculations, such as from the tight-binding model and first-principles calculations, and agree with experimental observations.

Simplifications for hydronic system models in modelica

DOE PAGES

Jorissen, F.; Wetter, M.; Helsen, L.

2018-01-12

Building systems and their heating, ventilation and air conditioning flow networks, are becoming increasingly complex. Some building energy simulation tools simulate these flow networks using pressure drop equations. These flow network models typically generate coupled algebraic nonlinear systems of equations, which become increasingly more difficult to solve as their sizes increase. This leads to longer computation times and can cause the solver to fail. These problems also arise when using the equation-based modelling language Modelica and Annex 60-based libraries. This may limit the applicability of the library to relatively small problems unless problems are restructured. This paper discusses two algebraicmore » loop types and presents an approach that decouples algebraic loops into smaller parts, or removes them completely. The approach is applied to a case study model where an algebraic loop of 86 iteration variables is decoupled into smaller parts with a maximum of five iteration variables.« less

Piloted simulator investigation of helicopter control systems effects on handling qualities during instrument flight

NASA Technical Reports Server (NTRS)

Forrest, R. D.; Chen, R. T. N.; Gerdes, R. M.; Alderete, T. S.; Gee, D. R.

1979-01-01

An exploratory piloted simulation was conducted to investigate the effects of the characteristics of helicopter flight control systems on instrument flight handling qualities. This joint FAA/NASA study was motivated by the need to improve instrument flight capability. A near-term objective is to assist in updating the airworthiness criteria for helicopter instrument flight. The experiment consisted of variations of single-rotor helicopter types and levels of stability and control augmentation systems (SCAS). These configurations were evaluated during an omnirange approach task under visual and instrument flight conditions. The levels of SCAS design included a simple rate damping system, collective decoupling plus rate damping, and an attitude command system with collective decoupling. A limited evaluation of stick force versus airspeed stability was accomplished. Some problems were experienced with control system mechanization which had a detrimental effect on longitudinal stability. Pilot ratings, pilot commentary, and performance data related to the task are presented.

Development and flight test experiences with a flight-crucial digital control system

NASA Technical Reports Server (NTRS)

Mackall, Dale A.

1988-01-01

Engineers and scientists in the advanced fighter technology integration (AFTI) F-16 program investigated the integration of emerging technologies into an advanced fighter aircraft. AFTI's three major technologies included: flight-crucial digital control, decoupled aircraft flight control, and integration of avionics, flight control, and pilot displays. In addition to investigating improvements in fighter performance, researchers studied the generic problems confronting the designers of highly integrated flight-crucial digital control. An overview is provided of both the advantages and problems of integration digital control systems. Also, an examination of the specification, design, qualification, and flight test life-cycle phase is provided. An overview is given of the fault-tolerant design, multimoded decoupled flight control laws, and integrated avionics design. The approach to qualifying the software and system designs is discussed, and the effects of design choices on system qualification are highlighted.

Eight-channel transmit/receive body MRI coil at 3T.

PubMed

Vernickel, P; Röschmann, P; Findeklee, C; Lüdeke, K-M; Leussler, Ch; Overweg, J; Katscher, U; Grässlin, I; Schünemann, K

2007-08-01

Multichannel transmit magnetic resonance imaging (MR) systems have the potential to compensate for signal-intensity variations occurring at higher field strengths due to wave propagation effects in tissue. Methods such as RF shimming and local excitation in combination with parallel transmission can be applied to compensate for these effects. Moreover, parallel transmission can be applied to ease the excitation of arbitrarily shaped magnetization patterns. The implementation of these methods adds new requirements in terms of MRI hardware. This article describes the design of a decoupled eight-element transmit/receive body coil for 3T. The setup of the coil is explained, starting with standard single-channel resonators. Special focus is placed on the decoupling of the elements to obtain independent RF resonators. After a brief discussion of the underlying theory, the properties and limitations of the coil are outlined. Finally, the functionality and capabilities of the coil are demonstrated using RF measurements as well as MRI sequences.

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

Divani, Nazila, E-mail: n-divani@birjand.ac.ir; Firoozabadi, Mohammad M.; Bayat, Esmail

Scintillators are almost used in any nuclear laboratory. These detectors combine of scintillation materials, PMT and a voltage divider. Voltage dividers are different in resistive ladder design. But the effect of decoupling capacitors and damping resistors haven’t discussed yet. In this paper at first a good equilibrium circuit designed for PMT, and it was used for investigating about capacitors and resistors in much manner. Results show that decoupling capacitors have great effect on PMT output pulses. In this research, it was tried to investigate the effect of Capacitor’s value and places on PMT voltage divider in Neutron-Gamma discrimination capability. Therefore,more » the voltage divider circuit for R329-02 Hamamatsu PMT was made and Zero Cross method used for neutron-gamma discrimination. The neutron source was a 20Ci Am-Be. Anode and Dynode pulses and discrimination spectrum were saved. The results showed that the pulse height and discrimination quality change with the value and setting of capacitors.« less

Plate convergence, transcurrent faults and internal deformation adjacent to Southeast Asia and the western Pacific

NASA Technical Reports Server (NTRS)

Fitch, T. J.

1971-01-01

A model for oblique convergence between plates of lithosphere is proposed in which at least a fraction of slip parallel to the plate margin results in transcurrent movements on a nearly vertical fault which is located on the continental side of a zone of plate consumption. In an extreme case of complete decoupling only the component of slip normal to the plate margin can be inferred from underthrusting. Recent movements in the western Sunda region provide the most convincing evidence for decoupling of slip, which in this region is thought to be oblique to the plate margin. A speculative model for convergence along the margins of the Philippine Sea is constructed from an inferred direction of oblique slip in the Philippine region. This model requires that the triple point formed by the junction of the Japanese and Izu-Bonin trenches and the Nankai trough migrate along the Sagami trough.

Wearable Stretch Sensors for Motion Measurement of the Wrist Joint Based on Dielectric Elastomers.

PubMed

Huang, Bo; Li, Mingyu; Mei, Tao; McCoul, David; Qin, Shihao; Zhao, Zhanfeng; Zhao, Jianwen

2017-11-23

Motion capture of the human body potentially holds great significance for exoskeleton robots, human-computer interaction, sports analysis, rehabilitation research, and many other areas. Dielectric elastomer sensors (DESs) are excellent candidates for wearable human motion capture systems because of their intrinsic characteristics of softness, light weight, and compliance. In this paper, DESs were applied to measure all component motions of the wrist joints. Five sensors were mounted to different positions on the wrist, and each one is for one component motion. To find the best position to mount the sensors, the distribution of the muscles is analyzed. Even so, the component motions and the deformation of the sensors are coupled; therefore, a decoupling method was developed. By the decoupling algorithm, all component motions can be measured with a precision of 5°, which meets the requirements of general motion capture systems.

The Neural Correlates Underlying Belief Reasoning for Self and for Others: Evidence from ERPs.

PubMed

Jiang, Qin; Wang, Qi; Li, Peng; Li, Hong

2016-01-01

Belief reasoning is typical mental state reasoning in theory of mind (ToM). Although previous studies have explored the neural bases of belief reasoning, the neural correlates of belief reasoning for self and for others are rarely addressed. The decoupling mechanism of distinguishing the mental state of others from one's own is essential for ToM processing. To address the electrophysiological bases underlying the decoupling mechanism, the present event-related potential study compared the time course of neural activities associated with belief reasoning for self and for others when the belief belonging to self was consistent or inconsistent with others. Results showed that during a 450-600 ms period, belief reasoning for self elicited a larger late positive component (LPC) than for others when beliefs were inconsistent with each other. The LPC divergence is assumed to reflect the categorization of agencies in ToM processes.

Mitigating Thermoelastic Dissipation of Flexural Micromechanical Resonators by Decoupling Resonant Frequency from Thermal Relaxation Rate

NASA Astrophysics Data System (ADS)

Zhou, Xin; Xiao, Dingbang; Wu, Xuezhong; Li, Qingsong; Hou, Zhanqiang; He, Kaixuan; Wu, Yulie

2017-12-01

This paper reports an alternative design strategy to reduce thermoelastic dissipation (TED) for isothermal-mode micromechanical resonators. This involves hanging lumped masses on a frame structure to decouple the resonant frequency and the effective beamwidth of the resonators, which enables the separation of the thermal relaxation rate and frequency of vibration. This approach is validated using silicon-based micromechanical disklike resonators engineered to isolate TED. A threefold improvement in the quality factor and a tenfold improvement in the decay-time constant is demonstrated. This work proposes a solution for isothermal-mode (flexural) micromechanical resonators to effectively mitigate TED. Specifically, this approach is ideal for designing high-performance gyroscope resonators based on microelectromechanical systems (MEMS) technology. It may pave the way for the next generation inertial-grade MEMS gyroscope, which remains a great challenge and is very appealing.

Singular perturbations and time scales in the design of digital flight control systems

NASA Technical Reports Server (NTRS)

Naidu, Desineni S.; Price, Douglas B.

1988-01-01

The results are presented of application of the methodology of Singular Perturbations and Time Scales (SPATS) to the control of digital flight systems. A block diagonalization method is described to decouple a full order, two time (slow and fast) scale, discrete control system into reduced order slow and fast subsystems. Basic properties and numerical aspects of the method are discussed. A composite, closed-loop, suboptimal control system is constructed as the sum of the slow and fast optimal feedback controls. The application of this technique to an aircraft model shows close agreement between the exact solutions and the decoupled (or composite) solutions. The main advantage of the method is the considerable reduction in the overall computational requirements for the evaluation of optimal guidance and control laws. The significance of the results is that it can be used for real time, onboard simulation. A brief survey is also presented of digital flight systems.

Iterative matrix algorithm for high precision temperature and force decoupling in multi-parameter FBG sensing.

PubMed

Hopf, Barbara; Dutz, Franz J; Bosselmann, Thomas; Willsch, Michael; Koch, Alexander W; Roths, Johannes

2018-04-30

A new iterative matrix algorithm has been applied to improve the precision of temperature and force decoupling in multi-parameter FBG sensing. For the first time, this evaluation technique allows the integration of nonlinearities in the sensor's temperature characteristic and the temperature dependence of the sensor's force sensitivity. Applied to a sensor cable consisting of two FBGs in fibers with 80 µm and 125 µm cladding diameter installed in a 7 m-long coiled PEEK capillary, this technique significantly reduced the uncertainties in friction-compensated temperature measurements. In the presence of high friction-induced forces of up to 1.6 N the uncertainties in temperature evaluation were reduced from several degrees Celsius if using a standard linear matrix approach to less than 0.5°C if using the iterative matrix approach in an extended temperature range between -35°C and 125°C.

Decoupled Ion Transport in a Protein-Based Solid Ion Conductor.

PubMed

Fu, Xuewei; Jewel, Yead; Wang, Yu; Liu, Jin; Zhong, Wei-Hong

2016-11-03

Simultaneous achievement of good electrochemical and mechanical properties is crucial for practical applications of solid ion conductors. Conventional polymer conductors suffer from low conductivity, low transference number, and deteriorated mechanical properties with the enhancement of conductivity, resulting from the coupling between ion transport and polymer movement. Here we present a successful fabrication and fundamental understanding of a high performance soy protein-based solid conductor. The conductor shows ionic conductivity of ∼10 -5 S/cm, transference number of 0.94, and modulus of 1 GPa at room temperature, and still remains flexible and easily processable. Molecular simulations indicate that this is due to appropriate manipulation of the protein structures for effective exploitation of protein functional groups. A decoupled transport mechanism, which is able to explain all results, is proposed. The new insights can be utilized to provide guidelines for design, optimization, and fabrication of high performance biosolid conductors.

Combining dynamical decoupling with fault-tolerant quantum computation

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

Ng, Hui Khoon; Preskill, John; Lidar, Daniel A.

2011-07-15

We study how dynamical decoupling (DD) pulse sequences can improve the reliability of quantum computers. We prove upper bounds on the accuracy of DD-protected quantum gates and derive sufficient conditions for DD-protected gates to outperform unprotected gates. Under suitable conditions, fault-tolerant quantum circuits constructed from DD-protected gates can tolerate stronger noise and have a lower overhead cost than fault-tolerant circuits constructed from unprotected gates. Our accuracy estimates depend on the dynamics of the bath that couples to the quantum computer and can be expressed either in terms of the operator norm of the bath's Hamiltonian or in terms of themore » power spectrum of bath correlations; we explain in particular how the performance of recursively generated concatenated pulse sequences can be analyzed from either viewpoint. Our results apply to Hamiltonian noise models with limited spatial correlations.« less

Maximizing the short circuit current of organic solar cells by partial decoupling of electrical and optical properties

NASA Astrophysics Data System (ADS)

Qarony, Wayesh; Hossain, Mohammad I.; Jovanov, Vladislav; Knipp, Dietmar; Tsang, Yuen Hong

2018-03-01

The partial decoupling of electronic and optical properties of organic solar cells allows for realizing solar cells with increased short circuit current and energy conversion efficiency. The proposed device consists of an organic solar cell conformally prepared on the surface of an array of single and double textured pyramids. The device geometry allows for increasing the optical thickness of the organic solar cell, while the electrical thickness is equal to the nominal thickness of the solar cell. By increasing the optical thickness of the solar cell, the short circuit current is distinctly increased. The quantum efficiency and short circuit current are determined using finite-difference time-domain simulations of the 3D solar cell structure. The influence of different solar cell designs on the quantum efficiency and short circuit current is discussed and optimal device dimensions are proposed.

High-harmonic generation in amorphous solids

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

You, Yong Sing; Yin, Yanchun; Wu, Yi

High-harmonic generation in isolated atoms and molecules has been widely utilized in extreme ultraviolet photonics and attosecond pulse metrology. Recently, high-harmonic generation has been observed in solids, which could lead to important applications such as all-optical methods to image valance charge density and reconstruct electronic band structures, as well as compact extreme ultraviolet light sources. So far these studies are confined to crystalline solids; therefore, decoupling the respective roles of long-range periodicity and high density has been challenging. Here we report the observation of high-harmonic generation from amorphous fused silica. We also decouple the role of long-range periodicity by comparingmore » harmonics generated from fused silica and crystalline quartz, which contain the same atomic constituents but differ in long-range periodicity. These results advance current understanding of the strong-field processes leading to high-harmonic generation in solids with implications for the development of robust and compact extreme ultraviolet light sources.« less

Decoupling global biases and local interactions between cell biological variables

PubMed Central

Zaritsky, Assaf; Obolski, Uri; Gan, Zhuo; Reis, Carlos R; Kadlecova, Zuzana; Du, Yi; Schmid, Sandra L; Danuser, Gaudenz

2017-01-01

Analysis of coupled variables is a core concept of cell biological inference, with co-localization of two molecules as a proxy for protein interaction being a ubiquitous example. However, external effectors may influence the observed co-localization independently from the local interaction of two proteins. Such global bias, although biologically meaningful, is often neglected when interpreting co-localization. Here, we describe DeBias, a computational method to quantify and decouple global bias from local interactions between variables by modeling the observed co-localization as the cumulative contribution of a global and a local component. We showcase four applications of DeBias in different areas of cell biology, and demonstrate that the global bias encapsulates fundamental mechanistic insight into cellular behavior. The DeBias software package is freely accessible online via a web-server at https://debias.biohpc.swmed.edu. DOI: http://dx.doi.org/10.7554/eLife.22323.001 PMID:28287393

Structural investigation of Titan tholins by solution-state 1H, 13C, and 15N NMR: one-dimensional and decoupling experiments.

PubMed

He, Chao; Lin, Guangxin; Upton, Kathleen T; Imanaka, Hiroshi; Smith, Mark A

2012-05-17

Titan, the largest moon of Saturn, is enveloped in a reddish brown organic haze. Titan haze is presumed to be formed from methane and nitrogen (CH(4) and N(2)) in Titan's upper atmosphere through energetic photochemistry and particle bombardment. Though Titan haze has been directly investigated using methods including the Cassini mission, its formation mechanism and the contributing chemical structures and prebiotic potential are still not well developed. We report here the structural investigation of the (13)C and (15)N labeled, simulated Titan haze aerosol (tholin) by solution-state NMR. The one-dimensional (1)H, (13)C, and (15)N NMR spectra and decoupling experiments indicate that the tholin sample contains amine, nitrile, imine, and N-heteroaromatic compounds of tremendous import in understanding complex organic chemistry in anaerobic, extraterrestrial environments.

Phase-modulated decoupling and error suppression in qubit-oscillator systems.

PubMed

Green, Todd J; Biercuk, Michael J

2015-03-27

We present a scheme designed to suppress the dominant source of infidelity in entangling gates between quantum systems coupled through intermediate bosonic oscillator modes. Such systems are particularly susceptible to residual qubit-oscillator entanglement at the conclusion of a gate period that reduces the fidelity of the target entangling operation. We demonstrate how the exclusive use of discrete shifts in the phase of the field moderating the qubit-oscillator interaction is sufficient to both ensure multiple oscillator modes are decoupled and to suppress the effects of fluctuations in the driving field. This approach is amenable to a wide variety of technical implementations including geometric phase gates in superconducting qubits and the Molmer-Sorensen gate for trapped ions. We present detailed example protocols tailored to trapped-ion experiments and demonstrate that our approach has the potential to enable multiqubit gate implementation with a significant reduction in technical complexity relative to previously demonstrated protocols.

Wireless power transfer system

DOEpatents

Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

2016-02-23

A system includes a first stage of an inductive power transfer system with an LCL load resonant converter with a switching section, an LCL tuning circuit, and a primary receiver pad. The IPT system includes a second stage with a secondary receiver pad, a secondary resonant circuit, a secondary rectification circuit, and a secondary decoupling converter. The secondary receiver pad connects to the secondary resonant circuit. The secondary resonant circuit connects to the secondary rectification circuit. The secondary rectification circuit connects to the secondary decoupling converter. The second stage connects to a load. The load includes an energy storage element. The second stage and load are located on a vehicle and the first stage is located at a fixed location. The primary receiver pad wirelessly transfers power to the secondary receiver pad across a gap when the vehicle positions the secondary receiver pad with respect to the primary receiver pad.

The Neural Correlates Underlying Belief Reasoning for Self and for Others: Evidence from ERPs

PubMed Central

Jiang, Qin; Wang, Qi; Li, Peng; Li, Hong

2016-01-01

Belief reasoning is typical mental state reasoning in theory of mind (ToM). Although previous studies have explored the neural bases of belief reasoning, the neural correlates of belief reasoning for self and for others are rarely addressed. The decoupling mechanism of distinguishing the mental state of others from one’s own is essential for ToM processing. To address the electrophysiological bases underlying the decoupling mechanism, the present event-related potential study compared the time course of neural activities associated with belief reasoning for self and for others when the belief belonging to self was consistent or inconsistent with others. Results showed that during a 450–600 ms period, belief reasoning for self elicited a larger late positive component (LPC) than for others when beliefs were inconsistent with each other. The LPC divergence is assumed to reflect the categorization of agencies in ToM processes. PMID:27757093

Non-minimal derivative couplings of the composite metric

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

Heisenberg, Lavinia, E-mail: laviniah@kth.se

2015-11-01

In the context of massive gravity, bi-gravity and multi-gravity non-minimal matter couplings via a specific composite effective metric were investigated recently. Even if these couplings generically reintroduce the Boulware-Deser ghost, this composite metric is unique in the sense that the ghost reemerges only beyond the decoupling limit and the matter quantum loop corrections do not detune the potential interactions. We consider non-minimal derivative couplings of the composite metric to matter fields for a specific subclass of Horndeski scalar-tensor interactions. We first explore these couplings in the mini-superspace and investigate in which scenario the ghost remains absent. We further study thesemore » non-minimal derivative couplings in the decoupling-limit of the theory and show that the equation of motion for the helicity-0 mode remains second order in derivatives. Finally, we discuss preliminary implications for cosmology.« less

Non-minimal derivative couplings of the composite metric

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

Heisenberg, Lavinia; Department of Physics & The Oskar Klein Centre,AlbaNova University Centre, 10691 Stockholm

2015-11-04

In the context of massive gravity, bi-gravity and multi-gravity non-minimal matter couplings via a specific composite effective metric were investigated recently. Even if these couplings generically reintroduce the Boulware-Deser ghost, this composite metric is unique in the sense that the ghost reemerges only beyond the decoupling limit and the matter quantum loop corrections do not detune the potential interactions. We consider non-minimal derivative couplings of the composite metric to matter fields for a specific subclass of Horndeski scalar-tensor interactions. We first explore these couplings in the mini-superspace and investigate in which scenario the ghost remains absent. We further study thesemore » non-minimal derivative couplings in the decoupling-limit of the theory and show that the equation of motion for the helicity-0 mode remains second order in derivatives. Finally, we discuss preliminary implications for cosmology.« less

Decoupled electron and phonon transports in hexagonal boron nitride-silicene bilayer heterostructure

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

Cai, Yongqing; Pei, Qing-Xiang, E-mail: peiqx@ihpc.a-star.edu.sg, E-mail: zhangg@ihpc.a-star.edu.sg; Zhang, Gang, E-mail: peiqx@ihpc.a-star.edu.sg, E-mail: zhangg@ihpc.a-star.edu.sg

2016-02-14

Calculations based on the density functional theory and empirical molecular dynamics are performed to investigate interlayer interaction, electronic structure and thermal transport of a bilayer heterostructure consisting of silicene and hexagonal boron nitride (h-BN). In this heterostructure, the two layers are found to interact weakly via a non-covalent binding. As a result, the Dirac cone of silicene is preserved with the Dirac cone point being located exactly at the Fermi level, and only a small amount of electrons are transferred from h-BN to silicene, suggesting that silicene dominates the electronic transport. Molecular dynamics calculation results demonstrate that the heat currentmore » along h-BN is six times of that along silicene, suggesting that h-BN dominates the thermal transport. This decoupled role of h-BN and silicene in thermal and electronic transport suggests that the BN-silicene bilayer heterostructure is promising for thermoelectric applications.« less

Solar thermal power & gas turbine hybrid design with molten salt storage tank

NASA Astrophysics Data System (ADS)

Martín, Fernando; Wiesenberg, Ralf; Santana, Domingo

2017-06-01

Taking into consideration the need to decelerate the global climatic change, power generation has to shift from burning fossil fuel to renewable energy source in short medium period of time. In this work, we are presenting a new model of a solar-gas natural hybrid power cycle with the main aim of decoupling the solar generation system from the gas turbine system. The objective is to have high solar power contribution compared to conventional ISCC plants [2], producing firm and dispatchable electricity at the same time. The decoupling is motivated by the low solar contribution reached by the ISCC, which is technically limited to maximum of 15%, [4]. In our case, we have implemented a solar tower with molten salts as working fluid. Central receiver systems get higher performance than others systems, like parabolic trough technology [1], due to the higher temperature achieved in the heat transferred fluid HTF, close to 560°C.

Feedback linearizing control of a MIMO power system

NASA Astrophysics Data System (ADS)

Ilyes, Laszlo

Prior research has demonstrated that either the mechanical or electrical subsystem of a synchronous electric generator may be controlled using single-input single-output (SISO) nonlinear feedback linearization. This research suggests a new approach which applies nonlinear feedback linearization to a multi-input multi-output (MIMO) model of the synchronous electric generator connected to an infinite bus load model. In this way, the electrical and mechanical subsystems may be linearized and simultaneously decoupled through the introduction of a pair of auxiliary inputs. This allows well known, linear, SISO control methods to be effectively applied to the resulting systems. The derivation of the feedback linearizing control law is presented in detail, including a discussion on the use of symbolic math processing as a development tool. The linearizing and decoupling properties of the control law are validated through simulation. And finally, the robustness of the control law is demonstrated.

New nonlinear control algorithms for multiple robot arms

NASA Technical Reports Server (NTRS)

Tarn, T. J.; Bejczy, A. K.; Yun, X.

1988-01-01

Multiple coordinated robot arms are modeled by considering the arms as closed kinematic chains and as a force-constrained mechanical system working on the same object simultaneously. In both formulations, a novel dynamic control method is discussed. It is based on feedback linearization and simultaneous output decoupling technique. By applying a nonlinear feedback and a nonlinear coordinate transformation, the complicated model of the multiple robot arms in either formulation is converted into a linear and output decoupled system. The linear system control theory and optimal control theory are used to design robust controllers in the task space. The first formulation has the advantage of automatically handling the coordination and load distribution among the robot arms. In the second formulation, it was found that by choosing a general output equation it became possible simultaneously to superimpose the position and velocity error feedback with the force-torque error feedback in the task space.

Deferred slanted-edge analysis: a unified approach to spatial frequency response measurement on distorted images and color filter array subsets.

PubMed

van den Bergh, F

2018-03-01

The slanted-edge method of spatial frequency response (SFR) measurement is usually applied to grayscale images under the assumption that any distortion of the expected straight edge is negligible. By decoupling the edge orientation and position estimation step from the edge spread function construction step, it is shown in this paper that the slanted-edge method can be extended to allow it to be applied to images suffering from significant geometric distortion, such as produced by equiangular fisheye lenses. This same decoupling also allows the slanted-edge method to be applied directly to Bayer-mosaicked images so that the SFR of the color filter array subsets can be measured directly without the unwanted influence of demosaicking artifacts. Numerical simulation results are presented to demonstrate the efficacy of the proposed deferred slanted-edge method in relation to existing methods.

Research and simulation of the decoupling transformation in AC motor vector control

NASA Astrophysics Data System (ADS)

He, Jiaojiao; Zhao, Zhongjie; Liu, Ken; Zhang, Yongping; Yao, Tuozhong

2018-04-01

Permanent magnet synchronous motor (PMSM) is a nonlinear, strong coupling, multivariable complex object, and transformation decoupling can solve the coupling problem of permanent magnet synchronous motor. This paper gives a permanent magnet synchronous motor (PMSM) mathematical model, introduces the permanent magnet synchronous motor vector control coordinate transformation in the process of modal matrix inductance matrix transform through the matrix related knowledge of different coordinates of diagonalization, which makes the coupling between the independent, realize the control of motor current and excitation the torque current coupling separation, and derived the coordinate transformation matrix, the thought to solve the coupling problem of AC motor. Finally, in the Matlab/Simulink environment, through the establishment and combination between the PMSM ontology, coordinate conversion module, built the simulation model of permanent magnet synchronous motor vector control, introduces the model of each part, and analyzed the simulation results.

An alternative Biot's displacement formulation for porous materials.

PubMed

Dazel, Olivier; Brouard, Bruno; Depollier, Claude; Griffiths, Stéphane

2007-06-01

This paper proposes an alternative displacement formulation of Biot's linear model for poroelastic materials. Its advantage is a simplification of the formalism without making any additional assumptions. The main difference between the method proposed in this paper and the original one is the choice of the generalized coordinates. In the present approach, the generalized coordinates are chosen in order to simplify the expression of the strain energy, which is expressed as the sum of two decoupled terms. Hence, new equations of motion are obtained whose elastic forces are decoupled. The simplification of the formalism is extended to Biot and Willis thought experiments, and simpler expressions of the parameters of the three Biot waves are also provided. A rigorous derivation of equivalent and limp models is then proposed. It is finally shown that, for the particular case of sound-absorbing materials, additional simplifications of the formalism can be obtained.

Automatic guidance control of an articulated all-wheel-steered vehicle

NASA Astrophysics Data System (ADS)

Kim, Young Chol; Yun, Kyong-Han; Min, Kyung-Deuk

2014-04-01

This paper presents automatic guidance control of a single-articulated all-wheel-steered vehicle being developed by the Korea Railroad Research Institute. The vehicle has an independent drive motor on each wheel except for the front axle. The guidance controller is designed so that the vehicle follows the given reference path within permissible lateral deviations. We use a three-input/three-output linearised model derived from the nonlinear dynamic model of the vehicle. For the purpose of simplifying the controller and making it tunable, we consider a decentralised control configuration. We first design a second-order decoupling compensator for the two-input/two-output system that is strongly coupled and then design a first-order controller for each decoupled feedback loop by using the characteristic ratio assignment method. The simulation results for the nonlinear dynamic model indicate that the proposed control configuration successfully achieves the design objectives.

Instability-driven frequency decoupling between structure dynamics and wake fluctuations

NASA Astrophysics Data System (ADS)

Jin, Yaqing; Kim, Jin-Tae; Chamorro, Leonardo P.

2018-04-01

Flow-induced dynamics of flexible structures is, in general, significantly modulated by periodic vortex shedding. Experiments and numerical simulations suggest that the frequencies associated with the dominant motions of structures are highly coupled with those of the wake under low-turbulence uniform flow. Here we present experimental evidence that demonstrates a significant decoupling between the dynamics of simple structures and wake fluctuations for various geometries, Reynolds numbers, and mass ratios. High-resolution particle tracking velocimetry and hot-wire anemometry are used to quantitatively characterize the dynamics of the structures and wake fluctuations; a complementary planar particle image velocimetry measurement is conducted to illustrate distinctive flow patterns. Results show that for structures with directional stiffness, von Kármán vortex shedding might dominate the wake of bodies governed by natural-frequency motion. This phenomenon can be a consequence of Kelvin-Helmholtz instability, where the structural characteristics of the body dominate the oscillations.

Sliding Mode Thermal Control System for Space Station Furnace Facility

NASA Technical Reports Server (NTRS)

Jackson Mark E.; Shtessel, Yuri B.

1998-01-01

The decoupled control of the nonlinear, multiinput-multioutput, and highly coupled space station furnace facility (SSFF) thermal control system is addressed. Sliding mode control theory, a subset of variable-structure control theory, is employed to increase the performance, robustness, and reliability of the SSFF's currently designed control system. This paper presents the nonlinear thermal control system description and develops the sliding mode controllers that cause the interconnected subsystems to operate in their local sliding modes, resulting in control system invariance to plant uncertainties and external and interaction disturbances. The desired decoupled flow-rate tracking is achieved by optimization of the local linear sliding mode equations. The controllers are implemented digitally and extensive simulation results are presented to show the flow-rate tracking robustness and invariance to plant uncertainties, nonlinearities, external disturbances, and variations of the system pressure supplied to the controlled subsystems.

TALE proteins search DNA using a rotationally decoupled mechanism.

PubMed

Cuculis, Luke; Abil, Zhanar; Zhao, Huimin; Schroeder, Charles M

2016-10-01

Transcription activator-like effector (TALE) proteins are a class of programmable DNA-binding proteins used extensively for gene editing. Despite recent progress, however, little is known about their sequence search mechanism. Here, we use single-molecule experiments to study TALE search along DNA. Our results show that TALEs utilize a rotationally decoupled mechanism for nonspecific search, despite remaining associated with DNA templates during the search process. Our results suggest that the protein helical structure enables TALEs to adopt a loosely wrapped conformation around DNA templates during nonspecific search, facilitating rapid one-dimensional (1D) diffusion under a range of solution conditions. Furthermore, this model is consistent with a previously reported two-state mechanism for TALE search that allows these proteins to overcome the search speed-stability paradox. Taken together, our results suggest that TALE search is unique among the broad class of sequence-specific DNA-binding proteins and supports efficient 1D search along DNA.

Decoupling of mass flux and turbulent wind fluctuations in drifting snow

NASA Astrophysics Data System (ADS)

Paterna, E.; Crivelli, P.; Lehning, M.

2016-05-01

The wind-driven redistribution of snow has a significant impact on the climate and mass balance of polar and mountainous regions. Locally, it shapes the snow surface, producing dunes and sastrugi. Sediment transport has been mainly represented as a function of the wind strength, and the two processes assumed to be stationary and in equilibrium. The wind flow in the atmospheric boundary layer is unsteady and turbulent, and drifting snow may never reach equilibrium. Our question is therefore: what role do turbulent eddies play in initiating and maintaining drifting snow? To investigate the interaction between drifting snow and turbulence experimentally, we conducted several wind tunnel measurements of drifting snow over naturally deposited snow covers. We observed a coupling between snow transport and turbulent flow only in a weak saltation regime. In stronger regimes it self-organizes developing its own length scales and efficiently decoupling from the wind forcing.

Decoupling of epitaxial graphene via gold intercalation probed by dispersive Raman spectroscopy

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

Pillai, P. B., E-mail: p.pillai@sheffield.ac.uk, E-mail: m.desouza@sheffield.ac.uk; DeSouza, M., E-mail: p.pillai@sheffield.ac.uk, E-mail: m.desouza@sheffield.ac.uk; Narula, R.

Signatures of a superlattice structure composed of a quasi periodic arrangement of atomic gold clusters below an epitaxied graphene (EG) layer are examined using dispersive Raman spectroscopy. The gold-graphene system exhibits a laser excitation energy dependant red shift of the 2D mode as compared to pristine epitaxial graphene. The phonon dispersions in both the systems are mapped using the experimentally observed Raman signatures and a third-nearest neighbour tight binding electronic band structure model. Our results reveal that the observed excitation dependent Raman red shift in gold EG primarily arise from the modifications of the phonon dispersion in gold-graphene and showsmore » that the extent of decoupling of graphene from the underlying SiC substrate can be monitored from the dispersive nature of the Raman 2D modes. The intercalated gold atoms restore the phonon band structure of epitaxial graphene towards free standing graphene.« less

Magnetic field fluctuations analysis for the ion trap implementation of the quantum Rabi model in the deep strong coupling regime

NASA Astrophysics Data System (ADS)

Puebla, Ricardo; Casanova, Jorge; Plenio, Martin B.

2018-03-01

The dynamics of the quantum Rabi model (QRM) in the deep strong coupling regime is theoretically analyzed in a trapped-ion set-up. Recognizably, the main hallmark of this regime is the emergence of collapses and revivals, whose faithful observation is hindered under realistic magnetic dephasing noise. Here, we discuss how to attain a faithful implementation of the QRM in the deep strong coupling regime which is robust against magnetic field fluctuations and at the same time provides a large tunability of the simulated parameters. This is achieved by combining standing wave laser configuration with continuous dynamical decoupling. In addition, we study the role that amplitude fluctuations play to correctly attain the QRM using the proposed method. In this manner, the present work further supports the suitability of continuous dynamical decoupling techniques in trapped-ion settings to faithfully realize different interacting dynamics.

Simulator evaluation of the effects of reduced spoiler and thrust authority on a decoupled longitudinal control system during landings in wind shear

NASA Technical Reports Server (NTRS)

Miller, G. K., Jr.

1981-01-01

The effect of reduced control authority, both in symmetric spoiler travel and thrust level, on the effectiveness of a decoupled longitudinal control system was examined during the approach and landing of the NASA terminal configured vehicle (TCV) aft flight deck simulator in the presence of wind shear. The evaluation was conducted in a fixed-base simulator that represented the TCV aft cockpit. There were no statistically significant effects of reduced spoiler and thrust authority on pilot performance during approach and landing. Increased wind severity degraded approach and landing performance by an amount that was often significant. However, every attempted landing was completed safely regardless of the wind severity. There were statistically significant differences in performance between subjects, but the differences were generally restricted to the control wheel and control-column activity during the approach.

Nuclear and particle physics in the early universe

NASA Technical Reports Server (NTRS)

Schramm, D. N.

1981-01-01

Basic principles and implications of Big Bang cosmology are reviewed, noting the physical evidence of a previous universe temperature of 10,000 K and theoretical arguments such as grand unification decoupling indicating a primal temperature of 10 to the 15th eV. The Planck time of 10 to the -43rd sec after the Big Bang is set as the limit before which gravity was quantized and nothing is known. Gauge theories of elementary particle physics are reviewed for successful predictions of similarity in weak and electromagnetic interactions and quantum chromodynamic predictions for strong interactions. The large number of photons in the universe relative to the baryons is considered and the grand unified theories are cited as showing the existence of baryon nonconservation as an explanation. Further attention is given to quark-hadron phase transition, the decoupling for the weak interaction and relic neutrinos, and Big Bang nucleosynthesis.

PeV-scale dark matter as a thermal relic of a decoupled sector

DOE PAGES

Berlin, Asher; Hooper, Dan; Krnjaic, Gordan

2016-06-21

We consider a class of scenarios in which the dark matter is part of a heavy hidden sector that is thermally decoupled from the Standard Model in the early universe. The dark matter freezes-out by annihilating to a lighter, metastable state, whose subsequent abundance can naturally come to dominate the energy density of the universe. Moreover, when this state decays, it reheats the visible sector and dilutes all relic abundances, thereby allowing the dark matter to be orders of magnitude heavier than the weak scale. For concreteness, we consider a simple realization with a Dirac fermion dark matter candidate coupledmore » to a massive gauge boson that decays to the Standard Model through its kinetic mixing with hypercharge. Finally, we identify viable parameter space in which the dark matter can be as heavy as ~1-100 PeV without being overproduced in the early universe.« less

Application of modern control design methodology to oblique wing research aircraft

NASA Technical Reports Server (NTRS)

Vincent, James H.

1991-01-01

A Linear Quadratic Regulator synthesis technique was used to design an explicit model following control system for the Oblique Wing Research Aircraft (OWRA). The forward path model (Maneuver Command Generator) was designed to incorporate the desired flying qualities and response decoupling. The LQR synthesis was based on the use of generalized controls, and it was structured to provide a proportional/integral error regulator with feedforward compensation. An unexpected consequence of this design approach was the ability to decouple the control synthesis into separate longitudinal and lateral directional designs. Longitudinal and lateral directional control laws were generated for each of the nine design flight conditions, and gain scheduling requirements were addressed. A fully coupled 6 degree of freedom open loop model of the OWRA along with the longitudinal and lateral directional control laws was used to assess the closed loop performance of the design. Evaluations were performed for each of the nine design flight conditions.

Decoupled direct tracking control system based on use of a virtual track for multilayer disk with a separate guide layer

NASA Astrophysics Data System (ADS)

Tanaka, Yukinobu; Ogata, Takeshi; Imagawa, Seiji

2015-09-01

We developed a decoupled direct tracking control system for multilayer optical disk that uses a separate guide layer. Data marks are recorded on a recording layer immediately above the guide layer by using two spatially separated spots with different wavelengths. Accurate data mark recording requires that the relative positions of the corresponding spots on the recording layer and guide layer are maintained. However, a disk tilt can shift their relative positions and cause previously recorded data marks to be overwritten. Additionally, a two-input/two-output control system is susceptible to mutual interference phenomenon between the two outputs, which can destabilize tracking control. A tracking control system based on use of data marks previously recorded as a virtual track has been developed that prevents spot shifting and mutual interference even if the disk tilt reaches 0.7°, thereby preventing overwriting.

Decoupling indirect topographic cross-talk in band excitation piezoresponse force microscopy imaging and spectroscopy

DOE PAGES

Mazet, Lucie; Jesse, Stephen; Niu, Gang; ...

2016-06-20

Here, all scanning probe microscopies are subjected to topographic cross-talk, meaning the topography-related contrast in functional images. Here, we investigate the signatures of indirect topographic cross-talk in piezoresponse force microscopy (PFM) imaging and spectroscopy and its decoupling using band excitation (BE) method in ferroelectric BaTiO 3 deposited on the Si substrates with free standing nanopillars of diameter 50 nm. Comparison between the single-frequency PFM and BE-PFM results shows that the measured signal can be significantly distorted by topography-induced shifts in the contact resonance frequency and cantilever transfer function. However, with proper correction, such shifts do not affect PFM imaging andmore » hysteresis loop measurements. This suggests the necessity of an advanced approach, such as BE-PFM, for detection of intrinsic sample piezoresponse on the topographically non-uniform surfaces.« less

High-harmonic generation in amorphous solids

DOE PAGES

You, Yong Sing; Yin, Yanchun; Wu, Yi; ...

2017-09-28

High-harmonic generation in isolated atoms and molecules has been widely utilized in extreme ultraviolet photonics and attosecond pulse metrology. Recently, high-harmonic generation has been observed in solids, which could lead to important applications such as all-optical methods to image valance charge density and reconstruct electronic band structures, as well as compact extreme ultraviolet light sources. So far these studies are confined to crystalline solids; therefore, decoupling the respective roles of long-range periodicity and high density has been challenging. Here we report the observation of high-harmonic generation from amorphous fused silica. We also decouple the role of long-range periodicity by comparingmore » harmonics generated from fused silica and crystalline quartz, which contain the same atomic constituents but differ in long-range periodicity. These results advance current understanding of the strong-field processes leading to high-harmonic generation in solids with implications for the development of robust and compact extreme ultraviolet light sources.« less

Rock outcrops reduce temperature-induced stress for tropical conifer by decoupling regional climate in the semiarid environment.

PubMed

Locosselli, Giuliano Maselli; Cardim, Ricardo Henrique; Ceccantini, Gregório

2016-05-01

We aimed to understand the effect of rock outcrops on the growth of Podocarpus lambertii within a microrefuge. Our hypothesis holds that the growth and survival of this species depend on the regional climate decoupling provided by rock outcrops. To test this hypothesis, we characterized the microclimate of (1) surrounding vegetation, (2) rock outcrop corridors, and (3) adjacencies. We assessed population structure by collecting data of specimen stem diameter and height. We also assessed differences between vegetation associated or not with outcrops using satellite imaging. For dendrochronological analyses, we sampled 42 individuals. Tree rings of 31 individuals were dated, and climate-growth relationships were tested. Rock outcrops produce a favorable microclimate by reducing average temperature by 4.9 °C and increasing average air humidity by 12 %. They also reduce the variability of atmospheric temperature by 42 % and air humidity by 20 % supporting a vegetation with higher leaf area index. Within this vegetation, specimen height was strongly constrained by the outcrop height. Although temperature and precipitation modulate this species growth, temperature-induced stress is the key limiting growth factor for this population of P. lambertii. We conclude that this species growth and survival depend on the presence of rock outcrops. These topography elements decouple regional climate in a favorable way for this species growth. However, these benefits are restricted to the areas sheltered by rock outcrops. Although this microrefuge supported P. lambertii growth so far, it is unclear whether this protection would be sufficient to withstand the stress of future climate changes.

Decoupling effect and forecasting of economic growth and energy structure under the peak constraint of carbon emissions in China.

PubMed

Wang, Shijin; Li, Cunfang; Yang, Lizhu

2018-06-26

The decoupling effect between economic growth and energy structure was quantitatively analyzed from 1999 to 2014 across China. The results showed it existed weak decoupling effects in most regions. Based on the analysis of the influence of energy structure on carbon intensity, using scenario simulation methods and Markov chain modeling, the carbon intensity was predicted for China in 2020. The impact of energy structure adjustment on the carbon intensity to meet China's carbon target by 18 possible scenarios are calculated. Furthermore, the peak value of carbon emissions was also calculated in 2030. The results showed that the carbon intensity predicted for China in 2020 can be achieved regardless of whether the energy structure was adjusted or not when energy saving and carbon reduction policies maintained with economic growth at 6-7%. Moreover, given fixed energy structure growth, for each 1% of economic growth, the carbon intensity will decrease by about 3.5%. Given fixed economic growth, the decrease of energy intensity will be greater if the control of energy consumption is stronger. The effect of energy structure adjustment on the decreasing of carbon intensity will be 4% higher under constraints than without constraints. On average, the contribution of energy structure adjustment to achieving the carbon intensity target was calculated as 4% higher than that with constraints. In addition, given relatively fixed economic growth at 6-7%, the peak value of carbon emission in 2030 was calculated as 13.209 billion tons with constraints and 14.38 billion tons without constraints.

Zeaxanthin-independent energy quenching and alternative electron sinks cause a decoupling of the relationship between the photochemical reflectance index (PRI) and photosynthesis in an evergreen conifer during spring

PubMed Central

Fréchette, Emmanuelle; Wong, Christopher Y. S.; Junker, Laura Verena; Chang, Christine Yao-Yun; Ensminger, Ingo

2015-01-01

In evergreen conifers, the winter down-regulation of photosynthesis and its recovery during spring are the result of a reorganization of the chloroplast and adjustments of energy-quenching mechanisms. These phenological changes may remain undetected by remote sensing, as conifers retain green foliage during periods of photosynthetic down-regulation. The aim was to assess if the timing of the spring recovery of photosynthesis and energy-quenching characteristics are accurately monitored by the photochemical reflectance index (PRI) in the evergreen conifer Pinus strobus. The recovery of photosynthesis was studied using chlorophyll fluorescence, leaf gas exchange, leaf spectral reflectance, and photosynthetic pigment measurements. To assess if climate change might affect the recovery of photosynthesis, seedlings were exposed to cold spring conditions or warm spring conditions with elevated temperature. An early spring decoupling of the relationship between photosynthesis and PRI in both treatments was observed. This was caused by differences between the timing of the recovery of photosynthesis and the timing of carotenoid and chlorophyll pool size adjustments which are the main factors controlling PRI during spring. It was also demonstrated that zeaxanthin-independent NPQ mechanisms undetected by PRI further contributed to the early spring decoupling of the PRI–LUE relationship. An important mechanism undetected by PRI seems to involve increased electron transport around photosystem I, which was a significant energy sink during the entire spring transition, particularly in needles exposed to a combination of high light and cold temperatures. PMID:26386258

A double-quadrature radiofrequency coil design for proton-decoupled carbon-13 magnetic resonance spectroscopy in humans at 7T.

PubMed

Serés Roig, Eulalia; Magill, Arthur W; Donati, Guillaume; Meyerspeer, Martin; Xin, Lijing; Ipek, Ozlem; Gruetter, Rolf

2015-02-01

Carbon-13 magnetic resonance spectroscopy ((13) C-MRS) is challenging because of the inherent low sensitivity of (13) C detection and the need for radiofrequency transmission at the (1) H frequency while receiving the (13) C signal, the latter requiring electrical decoupling of the (13) C and (1) H radiofrequency channels. In this study, we added traps to the (13) C coil to construct a quadrature-(13) C/quadrature-(1) H surface coil, with sufficient isolation between channels to allow simultaneous operation at both frequencies without compromise in coil performance. Isolation between channels was evaluated on the bench by measuring all coupling parameters. The quadrature mode of the quadrature-(13) C coil was assessed using in vitro (23) Na gradient echo images. The signal-to-noise ratio (SNR) was measured on the glycogen and glucose resonances by (13) C-MRS in vitro, compared with that obtained with a linear-(13) C/quadrature-(1) H coil, and validated by (13) C-MRS in vivo in the human calf at 7T. Isolation between channels was better than -30 dB. The (23) Na gradient echo images indicate a region where the field is strongly circularly polarized. The quadrature coil provided an SNR enhancement over a linear coil of 1.4, in vitro and in vivo. It is feasible to construct a double-quadrature (13) C-(1) H surface coil for proton decoupled sensitivity enhanced (13) C-NMR spectroscopy in humans at 7T. © 2014 Wiley Periodicals, Inc.

A safety vs efficiency trade-off identified in the hydraulic pathway of grass leaves is decoupled from photosynthesis, stomatal conductance and precipitation.

PubMed

Ocheltree, Troy W; Nippert, Jesse B; Prasad, P V Vara

2016-04-01

A common theme in plant physiological research is the trade-off between stress tolerance and growth; an example of this trade-off at the tissue level is the safety vs efficiency hypothesis, which suggests that plants with the greatest resistance to hydraulic failure should have low maximum hydraulic conductance. Here, we quantified the leaf-level drought tolerance of nine C4 grasses as the leaf water potential at which plants lost 50% (P50 × RR ) of maximum leaf hydraulic conductance (Ksat ), and compared this trait with other leaf-level and whole-plant functions. We found a clear trade-off between Ksat and P50 × RR when Ksat was normalized by leaf area and mass (P = 0.05 and 0.01, respectively). However, no trade-off existed between P50 × RR and gas-exchange rates; rather, there was a positive relationship between P50 × RR and photosynthesis (P = 0.08). P50 × RR was not correlated with species distributions based on precipitation (P = 0.70), but was correlated with temperature during the wettest quarter of the year (P < 0.01). These results suggest a trade-off between safety and efficiency in the hydraulic system of grass leaves, which can be decoupled from other leaf-level functions. The unique physiology of C4 plants and adaptations to pulse-driven systems may provide mechanisms that could decouple hydraulic conductance from other plant functions. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Spinal gap junctions: potential involvement in pain facilitation.

PubMed

Spataro, Leah E; Sloane, Evan M; Milligan, Erin D; Wieseler-Frank, Julie; Schoeniger, Diana; Jekich, Brian M; Barrientos, Ruth M; Maier, Steven F; Watkins, Linda R

2004-09-01

Glia are now recognized as important contributors in pathological pain creation and maintenance. Spinal cord glia exhibit extensive gap junctional connectivity, raising the possibility that glia are involved in the contralateral spread of excitation resulting in mirror image pain. In the present experiments, the gap junction decoupler carbenoxolone was administered intrathecally after induction of neuropathic pain in response to sciatic nerve inflammation (sciatic inflammatory neuropathy) or partial nerve injury (chronic constriction injury). In both neuropathic pain models, a low dose of carbenoxolone reversed mirror image mechanical allodynia, while leaving ipsilateral mechanical allodynia unaffected. Ipsilateral thermal hyperalgesia was briefly attenuated. Critically, blockade of mechanical allodynia and thermal hyperalgesia was not observed in response to intrathecal glycyrrhizic acid, a compound similar to carbenoxolone in all respects but it does not decouple gap junctions. Thus, blockade of mechanical allodynia and thermal hyperalgesia by carbenoxolone does appear to reflect an effect on gap junctions. Examination of carbenoxolone's effects on intrathecal human immunodeficiency virus type 1 gp120 showed that blockade of pain facilitation might result, at least in part, via suppression of interleukin-1 and, in turn, interleukin-6. These data provide the first suggestion that spread of excitation via gap junctions might contribute importantly to inflammatory and traumatic neuropathic pain. The current studies provide evidence for involvement of gap junctions in spinal cord pain facilitation. Intrathecal carbenoxolone, a gap junction decoupler, reversed neuropathy-induced mirror image pain and intrathecal gp120-induced allodynia. In addition, it decreased gp120-induced proinflammatory cytokines. This suggests gap junction activation might lead to proinflammatory cytokine release by distantly activated glia.

Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

DOE PAGES

Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.

2015-03-01

The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporatedmore » before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)« less