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1

Design of experiment for hysteresis loops measurement  

NASA Astrophysics Data System (ADS)

Hysteresis loop measurements are frequently used to assess the magnetic quality of a nanomaterial under an external magnetic field. Based on the values of the hysteresis parameters, it is possible to decide whether the nanomaterial meets requirements of a given application. In this work, we present a new approach to the measurement of the hysteresis loop based on the theory of optimal experimental design. We show that the maximin efficient design leads to a reduction in the measurements costs when compared to the standard equispaced measurement design. Moreover, a significantly higher accuracy in the estimation of hysteresis parameters is reached within a broad range of plausible values. The functionality of the proposed approach is successfully tested considering real experimental data obtained from the hysteresis loop measurements of the ?-Fe2O3 phase. The measurement procedure can be easily adapted to any magnetic nanomaterial for which the values of its hysteresis parameters are to be determined.

Tu?ková, Michaela; Harman, Radoslav; Tu?ek, Pavel; Tu?ek, Ji?í

2014-11-01

2

Understanding the Hysteresis Loop Conundrum in Pharmacokinetic / Pharmacodynamic Relationships  

PubMed Central

Hysteresis loops are phenomena that sometimes are encountered in the analysis of pharmacokinetic and pharmacodynamic relationships spanning from pre-clinical to clinical studies. When hysteresis occurs it provides insight into the complexity of drug action and disposition that can be encountered. Hysteresis loops suggest that the relationship between drug concentration and the effect being measured is not a simple direct relationship, but may have an inherent time delay and disequilibrium, which may be the result of metabolites, the consequence of changes in pharmacodynamics or the use of a non-specific assay or may involve an indirect relationship. Counter-clockwise hysteresis has been generally defined as the process in which effect can increase with time for a given drug concentration, while in the case of clockwise hysteresis the measured effect decreases with time for a given drug concentration. Hysteresis loops can occur as a consequence of a number of different pharmacokinetic and pharmacodynamic mechanisms including tolerance, distributional delay, feedback regulation, input and output rate changes, agonistic or antagonistic active metabolites, uptake into active site, slow receptor kinetics, delayed or modified activity, time-dependent protein binding and the use of racemic drugs among other factors. In this review, each of these various causes of hysteresis loops are discussed, with incorporation of relevant examples of drugs demonstrating these relationships for illustrative purposes. Furthermore, the effect that pharmaceutical formulation has on the occurrence and potential change in direction of the hysteresis loop, and the major pharmacokinetic / pharmacodynamic modeling approaches utilized to collapse and model hysteresis are detailed. PMID:24735761

Louizos, Christopher; Yáñez, Jaime A.; Forrest, Laird; Davies, Neal M.

2015-01-01

3

Completely inverted hysteresis loops: Inhomogeneity effects or experimental artifacts  

SciTech Connect

Completely inverted hysteresis loops (IHL) are obtained by the superconducting quantum interference device with large cooling fields (>10 kOe) in (La,Sr)MnO{sub 3} films with self-assembled LaSrMnO{sub 4}, an antiferromagnetic interface. Although the behaviours of measured loops show many features characteristic to the IHL, its origin, however, is not due to the exchange coupling between (La,Sr)MnO{sub 3}/LaSrMnO{sub 4}, an often accepted view on IHL. Instead, we demonstrate that the negative remanence arises from the hysteresis of superconducting coils, which drops abruptly when lower cooling fields are utilized. Hence the completely inverted hysteresis loops are experimental artifacts rather than previously proposed inhomogeneity effects in complicated materials.

Song, C., E-mail: songcheng@mail.tsinghua.edu.cn; Cui, B.; Pan, F., E-mail: panf@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yu, H. Y. [Center for Testing and Analyzing of Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

2013-11-14

4

Dielectric Hysteresis Loop in Alicyclic and Aromatic Polyamides  

NASA Astrophysics Data System (ADS)

The relationship between electric displacement D and electric field E was studied for alicyclic polyamides of 1,3-bis(aminomethyl)cyclohexane and adipic, pimelic and sebacic acids, an aromatic polyamide prepared from hexamethylenediamine (HMD) and isophthalic acid and a copolyamide of HMD with isophthalic and terephthalic acids. Quenched samples of these polyamides were poorly crystalline or amorphous and exhibited a D-E hysteresis loop with the remanent polarization of 26 to 38 mC·m-2. The remanent polarizations disappeared at the glass transition temperature of each sample. The origin of the D-E hysteresis loop is attributable to amide groups in amorphous regions.

Murata, Yukinobu; Tsunashima, Kenji; Koizumi, Naokazu

1994-03-01

5

Why Are Some Hysteresis Loops Shaped Like a Butterfly? Bojana Drincic a  

E-print Network

Why Are Some Hysteresis Loops Shaped Like a Butterfly? Bojana Drinci´c a , Xiaobo Tan b , Dennis S The contribution of this paper is a framework for relating butterfly-shaped hysteresis maps to simple (single, a unimodal mapping is used to transform simple loops to butterfly loops. For the practically important class

Tan, Xiaobo

6

Role of measurement voltage on hysteresis loop shape in Piezoresponse Force Microscopy  

SciTech Connect

The dependence of on-field and off-field hysteresis loop shape in Piezoresponse Force Microscopy (PFM) on driving voltage, Vac, is explored. A nontrivial dependence of hysteresis loop parameters on measurement conditions is observed. The strategies to distinguish between paraelectric and ferroelectric states with small coercive bias and separate reversible hysteretic and non-hysteretic behaviors are suggested. Generally, measurement of loop evolution with Vac is a necessary step to establish the veracity of PFM hysteresis measurements.

Kim, Yunseok [ORNL; Yang, J.-C. [University of California, Berkeley; Chu, Ying Hao [National Chiao Tung University, Hsinchu, Taiwan; Yu, Pu [University of California, Berkeley; Lu, X. [Xidian University, China; Jesse, Stephen [ORNL; Kalinin, Sergei V [ORNL

2012-01-01

7

Temperature-electric field hysteresis loop of electrocaloric effect in ferroelectricity—Direct measurement and analysis of electrocaloric effect. I  

NASA Astrophysics Data System (ADS)

The polarization of polar domain in ferroelectric materials is orientated and reversed with the alternating electric field, and the hysteresis loops of polarization-electric field (P-E) and strain-electric field (S-E) are observed. For electrocaloric (EC) effect, the temperature change with the application and removal of electric field is also attributed to the change of polarization with the applied field. In most reports about EC, the temperature change is shown as an abrupt jump or slump due to the applied electric field that is a pulsed wave. Obviously, it is impossible to observe the hysteresis loop of EC. In our research, both sine wave and pulsed wave electric field are applied to samples in direct measurement, and temperature-electric field hysteresis loop (T-E) is observed only in measurement of sine wave. The T-E hysteresis loop displays a shape of butterfly, just like the shape of S-E. The electric field dependence of EC is also given. The obtained results will be helpful for us to know the electrocaloric effect further.

Wang, Jinfei; Yang, Tongqing; Wei, Kun; Yao, Xi

2013-04-01

8

On the Rayleigh law of magnetization: A new mathematical model of hysteresis loops  

NASA Astrophysics Data System (ADS)

A mathematical model of magnetic hysteresis loops for weak ac magnetic fields, which is applicable for both symmetrical hysteresis loops that are described by the Rayleigh law of magnetization and asymmetrical loops that are not, has been formulated. The asymmetrical hysteresis loops take place when the ferromagnet is affected, along with an ac magnetizing field, by a dc field. The frequency spectrum of a ferromagnet magnetization has been analyzed as a time function. A technique for experimental determination of parameters that enter into this model is proposed, which uses amplitudes and phases of the first three magnetization harmonic components (the first, the second, and the third ones).

Ponomarev, Yu. F.

2007-11-01

9

Magnetic biasing of a ferroelectric hysteresis loop in a multiferroic orthoferrite.  

PubMed

In a multiferroic orthoferrite Dy0.7Tb0.3FeO3, which shows electric-field-(E-)driven magnetization (M) reversal due to a tight clamping between polarization (P) and M, a gigantic effect of magnetic-field (H) biasing on P-E hysteresis loops is observed in the case of rapid E sweeping. The magnitude of the bias E field can be controlled by varying the magnitude of H, and its sign can be reversed by changing the sign of H or the relative clamping direction between P and M. The origin of this unconventional biasing effect is ascribed to the difference in the Zeeman energy between the +P and -P states coupled with the M states with opposite sign. PMID:24484164

Tokunaga, Y; Taguchi, Y; Arima, T; Tokura, Y

2014-01-24

10

Comprehensive modelling of dynamic hysteresis loops in the rolling and transverse directions for transformer laminations  

NASA Astrophysics Data System (ADS)

Magnetic properties of grain-oriented materials are affected by hysteresis, anisotropy and dynamic effects. The attempts to describe dynamic hysteresis loops are usually limited to the rolling direction (RD). On the other hand, modelling of magnetic properties for the transverse direction (TD) is important for numerical analysis of core-joints and corner regions in transformers. For this direction, hysteresis loops reveal complex shapes particularly for dynamic magnetization conditions. This paper presents a comprehensive approach for modelling of dynamic hysteresis loops in RD and TD. This work uses the magnetic viscosity-based approach, which is able to describe irregular widening of dynamic loops. The loss separation scheme is also considered for both principal directions. Variations of loss components with frequency for both directions are discussed. The computed dynamic loops in RD and TD are in a close agreement with experimental ones.

Baghel, A. P. S.; Gupta, A.; Chwastek, K.; Kulkarni, S. V.

2015-04-01

11

Research on the Dynamic Hysteresis Loop Model of the Residence Times Difference (RTD)-Fluxgate  

PubMed Central

Based on the core hysteresis features, the RTD-fluxgate core, while working, is repeatedly saturated with excitation field. When the fluxgate simulates, the accurate characteristic model of the core may provide a precise simulation result. As the shape of the ideal hysteresis loop model is fixed, it cannot accurately reflect the actual dynamic changing rules of the hysteresis loop. In order to improve the fluxgate simulation accuracy, a dynamic hysteresis loop model containing the parameters which have actual physical meanings is proposed based on the changing rule of the permeability parameter when the fluxgate is working. Compared with the ideal hysteresis loop model, this model has considered the dynamic features of the hysteresis loop, which makes the simulation results closer to the actual output. In addition, other hysteresis loops of different magnetic materials can be explained utilizing the described model for an example of amorphous magnetic material in this manuscript. The model has been validated by the output response comparison between experiment results and fitting results using the model. PMID:24002230

Wang, Yanzhang; Wu, Shujun; Zhou, Zhijian; Cheng, Defu; Pang, Na; Wan, Yunxia

2013-01-01

12

Research on the dynamic hysteresis loop model of the residence times difference (RTD)-fluxgate.  

PubMed

Based on the core hysteresis features, the RTD-fluxgate core, while working, is repeatedly saturated with excitation field. When the fluxgate simulates, the accurate characteristic model of the core may provide a precise simulation result. As the shape of the ideal hysteresis loop model is fixed, it cannot accurately reflect the actual dynamic changing rules of the hysteresis loop. In order to improve the fluxgate simulation accuracy, a dynamic hysteresis loop model containing the parameters which have actual physical meanings is proposed based on the changing rule of the permeability parameter when the fluxgate is working. Compared with the ideal hysteresis loop model, this model has considered the dynamic features of the hysteresis loop, which makes the simulation results closer to the actual output. In addition, other hysteresis loops of different magnetic materials can be explained utilizing the described model for an example of amorphous magnetic material in this manuscript. The model has been validated by the output response comparison between experiment results and fitting results using the model. PMID:24002230

Wang, Yanzhang; Wu, Shujun; Zhou, Zhijian; Cheng, Defu; Pang, Na; Wan, Yunxia

2013-01-01

13

Experiments on Snap Buckling, Hysteresis and Loop Formation in Twisted Rods  

E-print Network

Experiments on Snap Buckling, Hysteresis and Loop Formation in Twisted Rods by V.G.A. Goss, G. In this way, commonly encountered phenomena are investigated, such as snap buckling, the formation of loops, rod experiments, snap buckling, loop formation, snarling, hockling, welded boundary condi- tions

Neukirch, Sébastien

14

Experiments on snap buckling, hysteresis and loop formation in twisted rods.  

E-print Network

Experiments on snap buckling, hysteresis and loop formation in twisted rods. V.G.A.Goss, G encountered phenomena such as snap­buckling, the formation of loops, and buckling into and out of planar, snap buckling, loop formation, snarling, hock­ ling, welded boundary conditions. 1 Introduction

Neukirch, Sébastien

15

Experiments on snap buckling, hysteresis and loop formation in twisted rods  

E-print Network

Experiments on snap buckling, hysteresis and loop formation in twisted rods V.G.A. Goss , G phenomena such as snap buckling, the formation of loops, and buckling into and out of planar configurations are investigated. The effect of gravity is discussed. Key words: twisted rods, rod experiments, snap buckling, loop

van der Heijden, Gert

16

Material Data Representation of Hysteresis Loops for Hastelloy X Using Artificial Neural Networks  

NASA Technical Reports Server (NTRS)

The artificial neural network (ANN) model proposed by Rumelhart, Hinton, and Williams is applied to develop a functional approximation of material data in the form of hysteresis loops from a nickel-base superalloy, Hastelloy X. Several different ANN configurations are used to model hysteresis loops at different cycles for this alloy. The ANN models were successful in reproducing the hysteresis loops used for its training. However, because of sharp bends at the two ends of hysteresis loops, a drift occurs at the corners of the loops where loading changes to unloading and vice versa (the sharp bends occurred when the stress-strain curves were reproduced by adding stress increments to the preceding values of the stresses). Therefore, it is possible only to reproduce half of the loading path. The generalization capability of the network was tested by using additional data for two other hysteresis loops at different cycles. The results were in good agreement. Also, the use of ANN led to a data compression ratio of approximately 22:1.

Alam, Javed; Berke, Laszlo; Murthy, Pappu L. N.

1993-01-01

17

A macroscopic theory for the existence of the hysteresis and butterfly loops in ferroelectricity  

Microsoft Academic Search

We present in this paper a minimal macroscopic theory leading to the hysteresis loop and the butterfly loop in ferroelectricity. This theory is based on the notion that as domains switch under the action of an external electric field the number of dipoles aligned in the direction of the field also alters and it obeys a rate law which depends

Peter J. Chen; Stephen T. Montgomery

1980-01-01

18

Study of the fast photoswitching of spin crossover nanoparticles outside and inside their thermal hysteresis loop  

NASA Astrophysics Data System (ADS)

We have studied the low spin to high spin phase transition induced by nanosecond laser pulses outside and within the thermal hysteresis loop of the [Fe(Htrz)2 trz](BF4)2-H2O spin crossover nanoparticles. We demonstrate that, whatever the temperature of the compound, the photo-switching is achieved in less than 12.5 ns. Outside the hysteresis loop, the photo-induced high spin state remains up to 100 ?s and then relaxes. Within the thermal hysteresis loop, the photo-induced high spin state remains as long as the temperature of the sample is kept within the thermal loop. A Raman study indicates that the photo-switching can be completed using single laser pulse excitation.

Gallé, G.; Etrillard, C.; Degert, J.; Guillaume, F.; Létard, J.-F.; Freysz, E.

2013-02-01

19

Efficient hysteresis loop simulations of nanoparticle assemblies beyond the uniaxial anisotropy  

NASA Astrophysics Data System (ADS)

We propose a modified Stoner-Wohlfarth model combined with the geometrical approach of the coherent rotation of magnetization for simulating the hysteresis loops of an assembly of magnetic nanoparticles. The temperature and the size distribution are taken into account. This combined model enables the computation of hysteresis loops at low temperatures for assemblies of particles having an arbitrary type of anisotropy. The applicability of this model for fitting experimental data is discussed and results are compared to the zero-field-cooled and field-cooled fits. As an application, the hysteresis loops measured on Co clusters embedded in carbon and germanium matrices are fitted revealing unambiguously the presence of a biaxial anisotropy.

Tamion, Alexandre; Bonet, Edgar; Tournus, Florent; Raufast, Cécile; Hillion, Arnaud; Gaier, Oksana; Dupuis, Véronique

2012-04-01

20

Scaling Behavior of Barkhausen Avalanches along the Hysteresis loop in Nucleation-Mediated Magnetization Reversal Process  

SciTech Connect

We report the scaling behavior of Barkhausen avalanches for every small field step along the hysteresis loop in CoCrPt alloy film having perpendicular magnetic anisotropy. Individual Barkhausen avalanche is directly observed utilizing a high-resolution soft X-ray microscopy that provides real space images with a spatial resolution of 15 nm. Barkhausen avalanches are found to exhibit power-law scaling behavior at all field steps along the hysteresis loop, despite their different patterns for each field step. Surprisingly, the scaling exponent of the power-law distribution of Barkhausen avalanches is abruptly altered from 1 {+-} 0.04 to 1.47 {+-} 0.03 as the field step is close to the coercive field. The contribution of coupling among adjacent domains to Barkhausen avalanche process affects the sudden change of the scaling behavior observed at the coercivity-field region on the hysteresis loop of CoCrPt alloy film.

Im, Mi-Young; Fischer, Peter; Kim, D.-H.; Shin, S.-C.

2008-10-14

21

Investigation of the Temperature Hysteresis Phenomenon of a Loop Heat Pipe  

NASA Technical Reports Server (NTRS)

The temperature hysteresis phenomenon of a Loop Heat Pipe (LHP) was experimentally investigated. The temperature hysteresis was identified by the fact that the operating temperature depends upon not only the imposed power but also the previous history of the power variation. The temperature hysteresis could impose limitations on the LHP applications since the LHP may exhibit different steady-state operating temperatures at a given power input even when the condenser sink temperature remains unchanged. In order to obtain insight to this phenomenon, a LHP was tested at different elevations and tilts by using an elaborated power profile. A hypothesis was suggested to explain the temperature hysteresis. This hypothesis explains well the experimental observations. Results of this study provide a better understanding of the performance characteristics of the LHPS.

Kaya, Tarik; Ku, Jentung; Hoang, Triem; Cheung, Mark K.

1999-01-01

22

Hybrid models of hysteresis for mixed hysteretic loops in heterogeneous magnetic materials  

NASA Astrophysics Data System (ADS)

The mixed hysteresis behavior of counter-clockwise and clockwise loops has recently attracted the attention of the magnetics community, due to several experimental findings in inhomogeneous and hetero-structure magnetic systems. Various hybrid models are proposed here to address this behavior based on the superposition of standard hysteresis models and their newly developed clockwise variants. A special attention is also devoted to Bouc-Wen model, a typical clockwise often used by applied mechanics community, and to its relevance for mixed hysteresis. These clockwise and hybrid models have been implemented in an open-access academic software and their performance is illustrated by examples of hysteretic loops, first order reversal curves and diagrams simulated in this framework.

Dimian, M.; Andrei, P.; Grayson, M.

2014-05-01

23

Hysteresis Loop for a No-loaded, Delta-connected Transformer Model Deduced from Measurements  

NASA Astrophysics Data System (ADS)

At a transformer's steady-state condition, whereby a transformer and its load are constantly supplied by a sinusoidal source, the current-flux pair within the transformer core and its windings will cycle along a hysteresis loop. This nonlinear current-flux characteristic becomes important while at transformer gets reenergized. A remaining residual flux and the fact that a transformer is typically used up to its saturation level can lead to high-amplitude magnetizing inrush currents and associated voltage disturbances. These disturbances can be reduced by controlled transformer switching. In order to pre-evaluate the effect of a specific controlled transformer energization, pre-simulations can be applied. In that case the hysteresis loop and its saturation characteristic will become the most important model parameter. If the corresponding manufacturer specifications are not available a standard hysteresis loops can be used, but might come up with an inaccurate simulation result. Therefore, this paper analyses the measured 3-phase currents from two delta-connected power transformers by “Fourier Series” in order to deduce a single-phase hysteresis loop, which can be implemented into a typical 3-phase transformer model. Additionally, the saturation behavior of a power-transformer will be estimated and a comparison of ATP/EMTP simulations will conclude this paper.

Corrodi, Yves; Kamei, Kenji; Kohyama, Haruhiko; Ito, Hiroki

24

A power and wavelength detuning-dependent hysteresis loop in a single mode Fabry—Pérot laser diode  

NASA Astrophysics Data System (ADS)

In this paper, we observe experimentally the optical bistability induced by the side-mode injection power and wavelength detuning in a single mode Fabry—Pérot laser diode (SMFP-LD). Results show that the bistability characteristics of the dominant and injected modes are strongly dependent on the injected input optical power and wavelength detuning in an SMFP-LD. We observe three types of hysteresis loops: counterclockwise, clockwise, and butterfly hysteresis with various loop widths. In the case of a bistability loop caused by injection power, the transition from counterclockwise to clockwise in the hysteresis direction with the wavelength detuning from 0.028 nm to 0.112 nm is observed in a way of butterfly hysteresis for the dominant mode by increasing the wavelength detuning. The width of hysteresis loop, induced by wavelength detuning is also changed while the injection power is enhanced from -7 dBm to -5 dBm.

Wu, Jian-Wei; Bikash, Nakarmi

2013-08-01

25

Simulations of magnetic hysteresis loops at high temperatures  

SciTech Connect

The kinetic Monte-Carlo algorithm as well as standard micromagnetics are used to simulate MH loops of high anisotropy magnetic recording media at both short and long time scales over a wide range of temperatures relevant to heat-assisted magnetic recording. Microscopic parameters, common to both methods, were determined by fitting to experimental data on single-layer FePt-based media that uses the Magneto-Optic Kerr effect with a slow sweep rate of 700?Oe/s. Saturation moment, uniaxial anisotropy, and exchange constants are given an intrinsic temperature dependence based on published atomistic simulations of FePt grains with an effective Curie temperature of 680?K. Our results show good agreement between micromagnetics and kinetic Monte Carlo results over a wide range of sweep rates. Loops at the slow experimental sweep rates are found to become more square-shaped, with an increasing slope, as temperature increases from 300?K. These effects also occur at higher sweep rates, typical of recording speeds, but are much less pronounced. These results demonstrate the need for accurate determination of intrinsic thermal properties of future recording media as input to micromagnetic models as well as the sensitivity of the switching behavior of thin magnetic films to applied field sweep rates at higher temperatures.

Plumer, M. L.; Whitehead, J. P.; Fal, T. J. [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7 (Canada); Ek, J. van [Western Digital Corporation, San Jose, California 94588 (United States); Mercer, J. I. [Department of Computer Science, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7 (Canada)

2014-09-28

26

Determination of hysteresis loops in thermo-mechanical fatigue using isothermal stress-strain data  

Microsoft Academic Search

Thermo-mechanical fatigue stress-strain data on ferritic\\/austenitic steels and superalloys from a variety of sources are analyzed with regard to hysteresis loop stress asymmetry. This arises from a decoupling of the thermal and mechanical strain signals in the test technique so that many tension-compression load combinations are possible. Data from simplified isothermal and bithermal tests are also examined. Taking a typical

R. P. Skelton

1994-01-01

27

Small hysteresis loops investigations on high T sub c oxide superconductors  

SciTech Connect

In this paper results of investigations on small hysteresis loops of yttrium-based high temperature ceramical compounds are presented. A proposed theoretical model describing the magnetic induction profile in a sample has been used for numerical approximation of the experimental data. The results of this fitting procedure then allow one to obtain detailed information on the pinning force's magnetic field dependence as well as the critical current of ceramical compounds.

Sosnowski, J. (Polish Academy of Science, Electrical Inst., 04-703 Warszawa, Pozaryskiego 28 (PL)); Raabe, J.; Bobryk, E. (Warsaw Univ. of Technology, Dept. of Chemistry, 00-664 Warszawa, ul. Noakowskiego 3 (PL)); Gilewski, A.; Warchulska, J. (International Lab. for High Magnetic Fields and Temperature, 53-529 Wroclaw, Prochnika 95 (PL))

1991-08-10

28

ac Dynamics of Ferroelectric Domains from an Investigation of the Frequency Dependence of Hysteresis Loops  

SciTech Connect

We investigated nonequilibrium domain wall dynamics under an ac field by measuring the hystere- sis loops of epitaxial ferroelectric capacitors at various frequencies and temperatures. Polarization switching is induced mostly by thermally activated creep motion at lower frequencies, and by vis- cous ow motion at higher frequencies. The dynamic crossover between the creep and ow regimes unveils two frequency-dependent scaling regions of hysteresis loops. Based on these findings, we constructed a dynamic phase diagram for hysteretic ferroelectric domain dynamics in the presence of ac fields.

Yang, Sang Mo [Seoul National University; Jo, Ji Young [Seoul National University; Kim, T. H. [Seoul National University; Yoon, J. -G. [University of Suwon; Song, T. K. [Changwon National University; Lee, Ho Nyung [ORNL; Marton, Zsolt [ORNL; Park, S. [Korea Basic Science Institute, Korea; Jo, Y. [Korea Basic Science Institute, Korea; Noh, Tae Won [Seoul National University

2010-01-01

29

Statistical mechanics of DNA unzipping under periodic force: scaling behavior of hysteresis loops.  

PubMed

A simple model of DNA based on two interacting polymers has been used to study the unzipping of a double stranded DNA subjected to a periodic force. We propose a dynamical transition where, without changing the physiological condition, it is possible to bring DNA from the zipped or unzipped state to a new dynamic (hysteretic) state by varying the frequency of the applied force. Our studies reveal that the area of the hysteresis loop grows with the same exponents as of the isotropic spin systems. These exponents are amenable to verification in the force spectroscopic experiments. PMID:23829761

Kumar, Sanjay; Mishra, Garima

2013-06-21

30

Influence of fourfold anisotropy form on hysteresis loop shape in ferromagnetic nanostructures  

SciTech Connect

The dependence of the form of different mathematical depictions of fourfold magnetic anisotropies has been examined, using a simple macro-spin model. Strong differences in longitudinal and transverse hysteresis loops occur due to deviations from the usual phenomenological model, such as using absolute value functions. The proposed possible models can help understanding measurements on sophisticated magnetic nanosystems, like exchange bias layered structures employed in magnetic hard disk heads or magnetic nano-particles, and support the development of solutions with specific magnetization reversal behavior needed in novel magneto-electronic devices.

Ehrmann, Andrea [Niederrhein University of Applied Sciences, Faculty of Textile and Clothing Technology, 41065 Mönchengladbach (Germany); Blachowicz, Tomasz [Silesian University of Technology, Institute of Physics, Center for Science and Education, 44-100 Gliwice (Poland)

2014-08-15

31

Nonlinear susceptibility and dynamic hysteresis loops of magnetic nanoparticles with biaxial anisotropy  

NASA Astrophysics Data System (ADS)

The nonlinear ac susceptibility and dynamic magnetic hysteresis (DMH) of a single domain ferromagnetic particle with biaxial anisotropy subjected to both external ac and dc fields of arbitrary strength and orientation are treated via Brown's continuous diffusions model [W. F. Brown, Jr., Phys. Rev. 130, 1677 (1963)] of magnetization orientations. The DMH loops and nonlinear ac susceptibility strongly depend on the dc and ac field strengths, the polar angle between the easy axis of the particle, the external field vectors, temperature, and damping. In contrast to uniaxial particles, the nonlinear ac stationary response and DMH strongly depend on the azimuthal direction of the ac field and the biaxiality parameter ?.

Ouari, Bachir; Titov, Serguey V.; El Mrabti, Halim; Kalmykov, Yuri P.

2013-02-01

32

On the benefits of hysteresis effects for closed-loop separation control using plasma actuation  

NASA Astrophysics Data System (ADS)

Flow separation control by a non-thermal plasma actuator is considered for a NACA 0015 airfoil at a chord Reynolds number of 1.9 × 105. Static hysteresis in the lift coefficient is demonstrated for increasing and then decreasing sinusoidal voltage amplitude supplying a typical single dielectric barrier discharge actuator at the leading edge of the model. In addition to these open-loop experiments, unsteady surface pressure signals are examined for transient processes involving forced reattachment and natural separation. The results show that strong pressure oscillations in the relatively slow separation process, compared to reattachment, precede the ultimate massive flow separation. To enhance the contrast between the parts of the signal related to the attached flow and those related to the incipient separation, RMS estimate of filtered values of Cp is used to define a flow separation predictor that is implemented in feedback control. Two simple controllers are proposed, one based on a predefined threshold of the unsteady Cp and another that utilizes the flow separation predictor to identify incipient separation. The latter effectively leverages the hysteresis in the post-stall regime to reduce the electrical power consumed by the actuator while maintaining continuously attached flow.

Benard, N.; Cattafesta, L. N.; Moreau, E.; Griffin, J.; Bonnet, J. P.

2011-08-01

33

Magnetic Hysteresis Loop as a Tool for the Evaluation of Spheroidization of Cementites in Pearlitic Steels  

NASA Astrophysics Data System (ADS)

Pearlitic Fe-0.76wt.% C binary alloy was isothermally annealed at 700 °C up to 100 h to study the spheroidization of cementites and its effect on both the mechanical and magnetic properties with the aim to use the magnetic techniques for the evaluation of spheroidization in steels. Micro-Vickers hardness, magnetic hysteresis loop (MHL) measurements, optical and scanning electron microscopy studies were carried out at various lengths of time by interrupting the test. Microhardness and coercivity were decreased with increase in annealing time due to reduction in dislocation pinning and magnetic domain wall pinning for the breaking of cementite lamella and their subsequent transformation to spheroidal form. The microhardness and coercivity showed a very good correlation with the change in microstructure indicating that MHL would be a suitable non-destructive evaluation tool for the evaluation of spheroidized pearlitic steels.

Mohapatra, J. N.; Kamada, Y.

2015-04-01

34

New soft magnetic amorphous cobalt based alloys with high hysteresis loop linearity  

NASA Astrophysics Data System (ADS)

The new amorphous Co56÷59(Fe,Ni,Mn)21÷24(Si0.2B0.8)20-based metal alloys (AMA) with high saturation induction (BS>=1T) were developed. Toroidal tape wound magnetic cores made from these AMA after heat-magnetic treatment (HMT) in a reversal field are characterized by high hysteresis loop linearity, minimum effective magnetic permeability and its high field stability in combination with low coercivity Hc (1-3 A/m, 1 kHz). For the most prospecting alloy compositions the value of effective magnetic permeability decreases compared to known alloys up to 550 - 670 units and remains constant in the wide magnetic field range 1100 - 1300 A/m. Maximum remagnetization loop linearity is achieved after optimum HMT in high Ni containing AMAs, which are characterized by the record low squareness ratio values Ks=0.002-0.02 and Hc=1.0 A/m. Magnetic cores made from the new amorphous alloys can be used both in filter chokes of switch-mode power supply units and in matching mini-transformers of telecommunication systems; at that, high efficiency and accuracy of signal transmission including high frequency pulses are ensured under conditions of long-term influence of dc magnetic bias.

Nosenko, V. K.; Maslov, V. V.; Kochkubey, A. P.; Kirilchuk, V. V.

2008-02-01

35

A New Type Hysteresis Loop in SiN/GdFeCoSi/SiN Sandwich Structure  

NASA Astrophysics Data System (ADS)

A new type of inverted hysteresis loop was observed in an amorphous SiN/GdFeCoSi/SiN film, in which a magnetic GdFeCoSi layer with a thickness of 40 nm was sandwiched by SiN capping and buffer layers 5 nm thick. An inverted hysteresis loop with negative remanence appeared, when an applied field was perpendicular to the film plane, with remanance ratio of 0.4 and HC=120 Oe. An FMR experiment study showed that two magnetic phases existed in the system. A major magnetic phase had an easy-plane anisotropy and the other minor magnetic phase had an easy-normal anisotropy. By assuming an antiferromagnetic exchange coupling between them, the inverted loops can be explained.

Zhao, Yanling; Wang, Shiqi; Shono, Keiji; Yu, Xiangyou; Lu, Mu; Zhai, Hongru

36

Physical motivations of the constitutive relations for ferroelectric ceramics and the existence of butterfly and hysteresis loops  

SciTech Connect

The responses of ferroelectric ceramics can be quite complex depending on the physical processes to which they are subjected. Their mechanical, electromechanical and dielectric properties depend on domain switching, dipole dynamics and phase transformation which can be caused by external stimuli such as mechanical and electrical loadings, and temperature variations. A theory, taking into account the effects of domain switching and dipole dynamics, has been formulated, and in its present stage of development is sufficient to characterize various observable resonses. Specifically, a special case of the theory predicts the nature of the butterfly and hysteresis loops. The butterfly and hysteresis loops are manifestations of the mechanical, electro-mechanical and dielectric responses due to domain switching produced by cyclic electric fields. Comparisons of the predictions of the theory with experimental results are made in a pseudo one dimensional context.

Chen, P.J.

1982-01-01

37

A new method for validating fatigue mechanisms based on the correlated analysis of hysteresis loop parameters using the landau theory  

Microsoft Academic Search

The mechanism of the fatigue in sol-gel derived Pb(Zr,Ti)O3 thin films is investigated using a Landau theory-based lattice model where various degradation hypotheses are implemented. For mechanism validation, a correlated analysis of normalized hysteresis loop parameters is shown to be extremely valuable. The most likely mechanism is the formation of degraded regions gradually spreading across the sample surface, where switching

Dan Ricinschi; Alexandru Ionut Lerescu; Masanori Okuyama

2001-01-01

38

Room temperature study of the optical switching of a spin crossover compound inside its thermal hysteresis loop  

NASA Astrophysics Data System (ADS)

We have studied the low-spin to high spin state phase transition induced by a single or a sequence of nanosecond laser pulses within the thermal hysteresis loop of the [Fe(NH2-trz)3](NO3)2-H2O spin crossover compound. We demonstrate that the final state that is photoinduced can be finely controlled by changing the central wavelength and the energy of the laser pulses. A simple model accounts for the observed phenomena and paves the way for the practical applications to optical data storage at room temperature of spin state transition compounds.

Gallé, G.; Deldicque, D.; Degert, J.; Forestier, Th.; Létard, J.-F.; Freysz, E.

2010-01-01

39

X-ray diffraction investigation of a spin crossover hysteresis loop. P Guionneau1,  

E-print Network

@icmcb-bordeaux.cnrs.fr The nature and the mechanism of the magnetic hysteresis for the thermal spin crossover exhibited by an iron(II) compound is investigated by mean of variable temperature powder and single crystals X-ray diffraction in the spin crossover features according to the nature of the sample ­ powder or single crystal ­ that should

Boyer, Edmond

40

An air-cooled Litz wire coil for measuring the high frequency hysteresis loops of magnetic samples—A useful setup for magnetic hyperthermia applications  

NASA Astrophysics Data System (ADS)

A setup for measuring the high-frequency hysteresis loops of magnetic samples is described. An alternating magnetic field in the range 6-100 kHz with amplitude up to 80 mT is produced by a Litz wire coil. The latter is air-cooled using a forced-air approach so no water flow is required to run the setup. High-frequency hysteresis loops are measured using a system of pick-up coils and numerical integration of signals. Reproducible measurements are obtained in the frequency range of 6-56 kHz. Measurement examples on ferrite cylinders and on iron oxide nanoparticle ferrofluids are shown. Comparison with other measurement methods of the hysteresis loop area (complex susceptibility, quasi-static hysteresis loops, and calorific measurements) is provided and shows the coherency of the results obtained with this setup. This setup is well adapted to the magnetic characterization of colloidal solutions of magnetic nanoparticles for magnetic hyperthermia applications.

Connord, V.; Mehdaoui, B.; Tan, R. P.; Carrey, J.; Respaud, M.

2014-09-01

41

PHYSICAL REVIEW B 84, 224402 (2011) Anomalous magneto-optical Kerr hysteresis loops in Fe0.25TaS2  

E-print Network

, and superconductors. Charge density wave (CDW) states sometimes coexist, and compete with, superconductivity of the Kerr angle shows a clear hysteresis loop, but its shape sensitively changes with the wavelength. We was studied by magneto-optical (MO) Faraday effect.11 Real-time MO images revealed unusual dendritic domain

Kono, Junichiro

42

Double hysteresis loop induced by defect dipoles in ferroelectric Pb(Zr{sub 0.8}Ti{sub 0.2})O{sub 3} thin films  

SciTech Connect

Pb(Zr{sub 0.8}Ti{sub 0.2})O{sub 3} (PZT80/20) thin films were deposited on the Pt(111)/Ti/SiO{sub 2}/Si(100) substrates by RF magnetron sputtering. Mainly perovskite crystalline phase with highly (202)-preferred orientation, determined by x-ray diffraction, was formed in the lead zirconate titanate (PZT)(80/20) thin films. Polarization measurements of the unannealed and aged films showed a clear double hysteresis loop. However, the double hysteresis loop phenomenon was greatly suppressed in the PZT thin films annealed under pure oxygen, and thus they exhibited larger remnant polarization (P{sub r} = 6.3 {mu}C/cm{sup 2}). The related mechanism for the appearance of constricted and double hysteresis loops was investigated to be associated with the realignment and disassociation of defect dipoles via oxygen octahedral rotations or oxygen vacancy diffusion. The butterfly-shaped C-V characteristic curve with a valley gave further evidence for double hysteresis loop characteristic in the unannealed and aged PZT thin films.

Pu Yunti; Zhu Jiliang; Zhu Xiaohong; Luo Yuansheng; Wang Mingsong; Li Xuhai; Liu Jing; Zhu Jianguo; Xiao Dingquan [Department of Materials Science, Sichuan University, Chengdu 610064 (China)

2011-02-15

43

Asymmetric hysteresis loops and smearing of the dielectric anomaly at the transition temperature due to space charges in ferroelectric thin films  

E-print Network

Asymmetric hysteresis loops and smearing of the dielectric anomaly at the transition temperature-electrode interfaces, asymmetric surface fields, as well as space charge regions. In this study, we analyze the effect related to each other through EC- =EC+ may shift depending on the space charge concentration

Alpay, S. Pamir

44

The J-Meter Coercivity Spectrometer - Hysteresis Loop, IRM Acquisition Spectrum and Viscosity Spectrum in 6 Minutes  

NASA Astrophysics Data System (ADS)

The J-Meter Coercivity Spectrometer uses an innovative robust design for measuring a geological sample's magnetic hysteresis loop, IRM acquisition spectrum and viscosity spectrum in 6 minutes. With this tool, several labs around the world have been able measure large sample collections and develop useful magnetic proxies for a variety of paleoclimate, diagenesis and other studies. The main element of the J-meter is a pulse magnetometer, in which an electromotive force pulse is induced in an array of pick-up coils by the magnetic field of a sample moving at a high speed past the coils. The sample is placed near the rim of a 50 cm diameter plexiglas disk which rotates 18 times a second through the pole pieces of an electromagnet. Both the induced and remanent magnetization are measured during each rotation of the disk. Induced magnetization for hysteresis loops are measure with a set of pick-up coils mounted directly on the pole pieces, similar to the geometry used for a vibrating sample magnetometer. The magnetic remanence is measured with a second array of coils situated away from the electromagnet and surrounded by a three-layer mu-metal shield. The electromagnet field is ramped up to 500 mT, and the down to the opposite polarity (-500 mT). The J meter is called a coercivity spectrometer because it is particularly well suited to measuring the IRM acquisition curve with sufficient sensitivity and resolution to take the derivative which defines the coercivity spectrum. To finish each measurement, the magnetic field is cut to zero and the viscous demagnetization is monitored for 100s, mostly following a log(time) relationship but with perturbations determined by the grain size distribution of the finest grains. A suite of analysis programs have been developed to determine hysteresis parameters and S-ratios, and to characterize coercivity and viscosity spectra. We present a series of applications demonstrating the power of the J-Meter to trace sediment sources, paleoclimate variations and diagenetic alteration associate with bacterial activity.

Enkin, R. J.; Nourgaliev, D.; Iassonov, P.

2009-05-01

45

Disorder-driven hysteresis-loop criticality in Co/CoO-films.  

SciTech Connect

The effect of magnetic disorder on the magnetization reversal process in thin Co/CoO-films has been investigated. The antiferromagnetic CoO layer allows a reversible tuning of the magnetic disorder by simple temperature variation. For temperatures above a critical temperature T{sub c}, we observe a discontinuous magnetization reversal, whereas smooth magnetization loops occur for T < T{sub c}. Our measurements establish the existence of a disorder-driven critical point in the non-equilibrium phase diagram. In addition, we observe scaling behavior in the vicinity of the critical point and determine the critical exponents to {beta} = 0.022 {+-} 0.006 and {beta}{delta} = 0.30 {+-} 0.03.

Berger, A.; Inomata, A.; Jiang, J. S.; Pearson, J. E.; Bader, S. D.

2000-11-01

46

Revealing the origin of the vertical hysteresis loop shifts in an exchange biased Co/YMnO3 bilayer.  

PubMed

We have investigated exchange bias effects in bilayers composed of the antiferromagnetic o-YMnO(3) and ferromagnetic Co thin film by means of SQUID magnetometry, magnetoresistance, anisotropic magnetoresistance and the planar Hall effect. The magnetization and magneto-transport properties show pronounced asymmetries in the field and magnetization axes of the field hysteresis loops. Both exchange bias parameters, the exchange bias field H(E)(T) as well as the magnetization shift M(E)(T), vanish around the Néel temperature T(N) =/~ 45 K. We show that the magnetization shift M(E)(T) is also measured by a shift in the anisotropic magnetoresistance and planar Hall resistance having a similar temperature dependence as the one obtained from magnetization measurements. Because the o-YMnO(3) film is highly insulating, our results demonstrate that the M(E)(T) shift originates at the interface within the ferromagnetic Co layer. To show that the main results obtained are general and not because of some special characteristics of the o-YMO(3) layer, similar measurements were done in Co/CoO micro-wires. The transport and magnetization characterization of the micro-wires supports the main conclusion that these effects are related to the response of the ferromagnetic Co layer at the interface. PMID:22907198

Barzola-Quiquia, J; Lessig, A; Ballestar, A; Zandalazini, C; Bridoux, G; Bern, F; Esquinazi, P

2012-09-12

47

Dynamic hysteresis modelling  

NASA Astrophysics Data System (ADS)

A viscous-type dynamic hysteresis model (DHM) is developed. The DHM is compatible with static underlying model of any type and nature (Preisach or non-Preisach). The distinguishing features of the DHM are its arbitrary frequency dependence and the ability to control the shape of the dynamic hysteresis loop. The numerical method for the incorporation of the DHM in magnetodynamic computations is illustrated by a good agreement of modelled dynamic loops with measured loops of non-oriented and grain-oriented electrical steels.

Zirka, S. E.; Moroz, Y. I.; Marketos, P.; Moses, A. J.

2004-01-01

48

Simultaneous effects of surface spins: rarely large coercivity, high remanence magnetization and jumps in the hysteresis loops observed in CoFe2O4 nanoparticles.  

PubMed

Well-dispersed uniform cobalt ferrite nanoparticles were synthesized by thermal decomposition of a metal-organic salt in organic solvent with a high boiling point. Some of the nanoparticles were diluted in a SiO2 matrix and then the undiluted and diluted samples were characterized and their magnetic behavior explored. The undiluted and diluted samples exhibited maximum coercivity Hc of 23?817 and 15?056 Oe at 10 K, respectively, which are the highest values reported to date, and the corresponding ratios of remanence (Mr) to saturation (Ms) magnetization (Mr/Ms) were as high as 0.85 and 0.76, respectively. Interestingly, the magnetic properties of the samples changed at 200 K, which was observed in magnetic hysteresis M(H) loops and zero-field cooling curves as well as the temperature dependence of Hc, Mr/Ms, anisotropy, dipolar field, and the magnetic grain size. Below 200 K, both samples have large effective anisotropy, which arises from the surface spins, resulting in large Hc and Mr/Ms. Above 200 K, the effective anisotropy decreases because there is no contribution from surface spins, while the dipolar interaction increases, resulting in small Hc and Mr/Ms. Our results indicate that strong anisotropy and weak dipolar interaction tend to increase Hc and Mr/Ms, and also clarify that the jumps around H = 0 in M(H) loops can be attributed to the reorientation of surface spins. This work exposes the underlying mechanism in nanoscale magnetic systems, which should lead to improved magnetic performance. PMID:25787852

Xu, S T; Ma, Y Q; Zheng, G H; Dai, Z X

2015-04-01

49

Magnetic blocking from exchange interactions: slow relaxation of the magnetization and hysteresis loop observed in a dysprosium-nitronyl nitroxide chain compound with an antiferromagnetic ground state.  

PubMed

The combination of the anisotropic Dy(III) ion and organic radicals as spin carriers results in discrete and one-dimensional lanthanide-radical magnetic materials, namely, [Dy(hfac)(3)(NITThienPh)(2)] (1) and [Dy(2)(hfac)(6)(NITThienPh)(2)](n) (2; hfac =hexafluoroacetylacetonate, NITThienPh = 2-(5-phenyl-2-thienyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide). Linking monomeric 1 with the Dy(III) ion leads to the formation of polymeric 2, and the transformation between them is chemically controllable and reversible. The characterization of both static and dynamic magnetic properties shows that the dominant intrachain exchange interaction is important to observe magnetic bistability in 2 rather than that in 1. Monomeric 1 exhibits paramagnetic behavior, whereas polymeric 2 shows the unusual coexistence of superparamagnetic and two-step field-induced metamagnetic behaviors. The antiferromagnetic ground state of 2 does not prevent the dynamic relaxation of the magnetization with the finite-sized effect in the lanthanide-radical system. Energy barriers to thermally activated relaxation for 2 are 53 and 98?K in the low- and high-temperature regimes, respectively. A hysteresis loop is observed with the coercive field of 99?Oe at 2?K. PMID:23197464

Han, Tian; Shi, Wei; Niu, Zheng; Na, Bo; Cheng, Peng

2013-01-14

50

A magnetic hysteresis model  

NASA Technical Reports Server (NTRS)

The Passive Aerodynamically Stabilized Magnetically Damped Satellite (PAMS) will be deployed from the Space Shuttle and used as a target for a Shuttle-mounted laser. It will be a cylindrical satellite with several corner cube reflectors on the ends. The center of mass of the cylinder will be near one end, and aerodynamic torques will tend to align the axis of the cylinder with the spacecraft velocity vector. Magnetic hysteresis rods will be used to provide passive despin and oscillation-damping torques on the cylinder. The behavior of the hysteresis rods depends critically on the 'B/H' curves for the combination of materials and rod length-to-diameter ratio ('l-over-d'). These curves are qualitatively described in most Physics textbooks in terms of major and minor 'hysteresis loops'. Mathematical modeling of the functional relationship between B and H is very difficult. In this paper, the physics involved is not addressed, but an algorithm is developed which provides a close approximation to empirically determined data with a few simple equations suitable for use in computer simulations.

Flatley, Thomas W.; Henretty, Debra A.

1995-01-01

51

The dielectric properties and the hysteresis loops of the spin-1 Ising nanowire system with the effect of a negative core/shell coupling: A Monte Carlo study  

NASA Astrophysics Data System (ADS)

The Monte Carlo simulation technique has been used to study the effect of a negative core/shell coupling on the dielectric properties and the hysteresis behavior of the spin-1 Ising nanowire system with a square surface area. The influence of the temperature and the exchange coupling on the critical and compensation behaviors of the ferroelectric and ferrielectric nanowire are also investigated.

Benhouria, Y.; Essaoudi, I.; Ainane, A.; Ahuja, R.; Dujardin, F.

2014-09-01

52

Mechanical hysteresis due to microplasticity in alumina with microcracks  

Microsoft Academic Search

Stress-strain hysteresis in alumina with microcracks has been investigated by a loading–unloading test in the microstrain range around 10 While there remains a permanent strain after the initial loading, steady-state cyclic loading results in a single closed hysteresis loop with a symmetrical shape. Such a stabilized hysteresis loop is responsible for internal friction and can be attributed to the microplasticity

Y. Nishino; H. Ogawa; S. Asano

1992-01-01

53

Hysteresis in a quantized superfluid `atomtronic' circuit  

NASA Astrophysics Data System (ADS)

Atomtronics is an emerging interdisciplinary field that seeks to develop new functional methods by creating devices and circuits where ultracold atoms, often superfluids, have a role analogous to that of electrons in electronics. Hysteresis is widely used in electronic circuits--it is routinely observed in superconducting circuits and is essential in radio-frequency superconducting quantum interference devices. Furthermore, it is as fundamental to superfluidity (and superconductivity) as quantized persistent currents, critical velocity and Josephson effects. Nevertheless, despite multiple theoretical predictions, hysteresis has not been previously observed in any superfluid, atomic-gas Bose-Einstein condensate. Here we directly detect hysteresis between quantized circulation states in an atomtronic circuit formed from a ring of superfluid Bose-Einstein condensate obstructed by a rotating weak link (a region of low atomic density). This contrasts with previous experiments on superfluid liquid helium where hysteresis was observed directly in systems in which the quantization of flow could not be observed, and indirectly in systems that showed quantized flow. Our techniques allow us to tune the size of the hysteresis loop and to consider the fundamental excitations that accompany hysteresis. The results suggest that the relevant excitations involved in hysteresis are vortices, and indicate that dissipation has an important role in the dynamics. Controlled hysteresis in atomtronic circuits may prove to be a crucial feature for the development of practical devices, just as it has in electronic circuits such as memories, digital noise filters (for example Schmitt triggers) and magnetometers (for example superconducting quantum interference devices).

Eckel, Stephen; Lee, Jeffrey G.; Jendrzejewski, Fred; Murray, Noel; Clark, Charles W.; Lobb, Christopher J.; Phillips, William D.; Edwards, Mark; Campbell, Gretchen K.

2014-02-01

54

Discharge mode transition and hysteresis in inductively coupled plasma  

NASA Astrophysics Data System (ADS)

Experimental verification of the discharge mode transition and the hysteresis by considering matching circuit is investigated in inductively coupled plasma using measurements of the plasma density and the power absorption to the plasma. At an argon gas pressure of 100 mTorr where the hysteresis loop of the plasma density had been observed in some previous experiments, there is no hysteresis loop against either the input power or the absorbed power delivered via an automatic impedance matching network. At a higher gas pressure of 350 mTorr, however, the hysteresis loop is clearly seen as functions of both the absorbed power and the input power. This result suggests that the observed hysteresis is due to not only the matching effect but also the nonlinearity of the plasma during capacitive (E) to inductive (H) and H to E heating mode transitions.

Lee, Hyo-Chang; Kim, Dong-Hwan; Chung, Chin-Wook

2013-06-01

55

Hysteresis phenomena in the interaction process of conical shock waves: experimental and numerical investigations  

NASA Astrophysics Data System (ADS)

The interaction of two conical shock waves, one converging and straight and the other diverging and curvilinear, in an axisymmetric flow was investigated both experimentally and numerically. A double-loop hysteresis was discovered in the course of the experimental investigation. The double-loop hysteresis consisted of a major one, associated with the interaction between the boundary layer and the wave configuration, and a minor one, associated with the dual-solution phenomenon, which is known to be non-viscous-dependent. The minor hysteresis loop was found to be an internal hysteresis loop of the major one. As expected the numerical Euler calculations failed to detect the viscous-dependent major hysteresis loop but did succeed in obtaining the non-viscous-dependent minor (internal) hysteresis loop. In addition, multiple hysteresis loops, associated with the interaction between the shock wave configuration and the edge of the curvilinear mobile cone were also observed. The non-viscous minor hysteresis loop involved different overall shock wave reflection configurations, and the other hysteresis loops involved the same shock wave reflection configuration but different flow patterns.

Ben-Dor, G.; Vasiliev, E. I.; Elperin, T.; Chpoun, A.

2001-12-01

56

Efficient Computational Model of Hysteresis  

NASA Technical Reports Server (NTRS)

A recently developed mathematical model of the output (displacement) versus the input (applied voltage) of a piezoelectric transducer accounts for hysteresis. For the sake of computational speed, the model is kept simple by neglecting the dynamic behavior of the transducer. Hence, the model applies to static and quasistatic displacements only. A piezoelectric transducer of the type to which the model applies is used as an actuator in a computer-based control system to effect fine position adjustments. Because the response time of the rest of such a system is usually much greater than that of a piezoelectric transducer, the model remains an acceptably close approximation for the purpose of control computations, even though the dynamics are neglected. The model (see Figure 1) represents an electrically parallel, mechanically series combination of backlash elements, each having a unique deadband width and output gain. The zeroth element in the parallel combination has zero deadband width and, hence, represents a linear component of the input/output relationship. The other elements, which have nonzero deadband widths, are used to model the nonlinear components of the hysteresis loop. The deadband widths and output gains of the elements are computed from experimental displacement-versus-voltage data. The hysteresis curve calculated by use of this model is piecewise linear beyond deadband limits.

Shields, Joel

2005-01-01

57

Mathematical models of hysteresis  

Microsoft Academic Search

A new approach to Preisach's hysteresis model, which emphasizes its phenomenological nature and mathematical generality, is briefly described. Then the theorem which gives the necessary and sufficient conditions for the representation of actual hysteresis nonlinearities by Preisach's model is proven. The significance of this theorem is that it establishes the limits of applicability of this model.

I. Mayergoyz

1986-01-01

58

Capillary Condensation in Porous Materials. Hysteresis and Interaction Mechanism without Pore Blocking/Percolation Process  

E-print Network

Capillary Condensation in Porous Materials. Hysteresis and Interaction Mechanism without Pore loops, reversal curves, and subloops in p+-type porous silicon, a porous material composed of straight hysteresis loops which depends on the porous material (H1 for MCM-41 and SBA-15, H2 for porous glass and p

Paris-Sud XI, Université de

59

Plant thermal hysteresis proteins.  

PubMed

Proteins which produce a thermal hysteresis (i.e. lower the freezing point of water below the melting point) are common antifreezes in cold adapted poikilothermic animals, especially fishes from ice-laden seas and terrestrial arthropods. However, these proteins have not been previously identified in plants. 16 species of plants collected from northern Indiana in autumn and winter had low levels of thermal hysteresis activity, but activity was absent in summer. This suggests that thermal hysteresis proteins may be a fairly common winter adaptation in angiosperms. Winter stem fluid from the bittersweet nightshade, Solanum dulcamara L., also showed the recrystallization inhibition activity characteristic of the animal thermal hysteresis proteins (THPs), suggesting a possible function for the THPs in this freeze tolerant species. Other potential functions are discussed. Antibodies to an insect THP cross reacted on immunoelectroblots with proteins in S. dulcamara stem fluid, indicating common epitopes in the insect and plant THPs. PMID:1599942

Urrutia, M E; Duman, J G; Knight, C A

1992-05-22

60

Hysteresis in column systems  

NASA Astrophysics Data System (ADS)

In this paper one column of a telescopic construction of a bell tower is investigated. The hinges at the support of the column and at the connecting joint between the upper and lower columns are modelled with rotational springs. The characteristics of the springs are assumed to be non-linear and the hysteresis property of them is represented with the Preisach hysteresis model. The mass of the columns and the bell with the fly are concentrated to the top of the column. The tolling process is simulated with a cycling load. The elements of the column are considered completely rigid. The time iteration of the non-linear equations of the motion is evaluated by the Crank-Nicolson schema and the implemented non-linear hysteresis is handled by the fix-point technique. The numerical simulation of the dynamic system is carried out under different combination of soft, medium and hard hysteresis properties of hinges.

Ivanyi, P.; Ivanyi, A.

2015-02-01

61

Orientational hysteresis in swarms of active particles in external field  

E-print Network

Structure and ordering in swarms of active particles have much in common with condensed matter systems like magnets or liquid crystals. A number of important characteristics of such materials can be obtained via dynamic tests such as hysteresis. In this work, we show that dynamic hysteresis can be observed also in swarms of active particles and possesses similar properties to the counterparts in magnetic materials. To study the swarm dynamics, we use computer simulation of the active Brownian particle model with dissipative interactions. The swarm is confined to a narrow linear channel and one-dimensional polar order parameter is measured. In an oscillating external field, the order parameter demonstrates dynamic hysteresis with the shape of the loop and its area varying with the amplitude and frequency of the applied field, swarm density and the noise intensity. We measure the scaling exponents for the hysteresis loop area, which can be associated with the controllability of the swarm. Although the exponents...

Romensky, Maksym

2015-01-01

62

Theory of the hysteresis loop in ferromagnets  

E-print Network

for the inter- face profile Z(x,t)5 ^ Z(x,t) & jv ,tv on large scales is given by 1 geff ]Z ]t 5G? 2Z1h2hp1heff~x,vt !. ~9! Here ^& jv ,tv denotes the spatial and time average over scales jv and tv , respectively, and heff is the renormalized... wall is rough, w ~ L !5 ^ @ Z ~ x1!2Z~x2!#2& ux12x2u5L 1/2 ?l ~ L/Lc!z. ~12! Bumps in the domain walls that emerge from random clus- ters heal on time scales tv? l v S hp vl D z/ ~ z2z! ? l ghp S h hp 21 D 2z/ ~ 22z...

Lyuksyutov, Igor F.; Nattermann, T.; Pokrovsky, Valery L.

1999-01-01

63

Stabilization of a system with saturating, non-monotone hysteresis and frequency dependent power losses by a PD controller  

NASA Astrophysics Data System (ADS)

We prove the closed loop stability of a PD controller for certain systems with saturating, non-monotone hysteresis and frequency dependent power losses. Most controllers use inverse compensators to cancel out actuator hysteresis nonlinearity. We show that we can achieve stability of the closed-loop system without an explicit inverse computation (using least squares minimization or otherwise).

Ekanayake, D. B.; Iyer, R. V.

2015-02-01

64

Hysteresis of ionization waves  

SciTech Connect

A quasi-logistic, nonlinear model for ionization wave modes is introduced. Modes are due to finite size of the discharge and current feedback. The model consists of competing coupled modes and it incorporates spatial wave amplitude saturation. The hysteresis of wave mode transitions under current variation is reproduced. Sidebands are predicted by the model and found in experimental data. The ad hoc model is equivalent to a general--so-called universal--approach from bifurcation theory.

Dinklage, A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Bruhn, B.; Testrich, H. [Institut fuer Physik, E.-M.-Arndt Universitaet Greifswald, Felix-Hausdorff-Str. 6, 17487 Greifswald (Germany); Wilke, C. [Leibniz-Institut fuer Plasmaforschung und Technologie, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

2008-06-15

65

Rheological Hysteresis in Soft Glassy Materials  

NASA Astrophysics Data System (ADS)

The nonlinear rheology of a soft glassy material is captured by its constitutive relation, shear stress versus shear rate, which is most generally obtained by sweeping up or down the shear rate over a finite temporal window. For a huge amount of complex fluids, the up and down sweeps do not superimpose and define a rheological hysteresis loop. By means of extensive rheometry coupled to time-resolved velocimetry, we unravel the local scenario involved in rheological hysteresis for various types of well-studied soft materials. We introduce two observables that quantify the hysteresis in macroscopic rheology and local velocimetry, respectively, as a function of the sweep rate ?t-1. Strikingly, both observables present a robust maximum with ?t, which defines a single material-dependent time scale that grows continuously from vanishingly small values in simple yield stress fluids to large values for strongly time-dependent materials. In line with recent theoretical arguments, these experimental results hint at a universal time scale-based framework for soft glassy materials, where inhomogeneous flows characterized by shear bands and/or pluglike flow play a central role.

Divoux, Thibaut; Grenard, Vincent; Manneville, Sébastien

2013-01-01

66

Magnetic hysteresis in granular CuCo alloys  

NASA Astrophysics Data System (ADS)

Room-temperature hysteresis loops of granular Cu100-xCox alloys (5?x?15) obtained by planar flow casting in air and submitted to proper annealing treatments have been measured up to a field of 10 kOe by means of a vibrating sample magnetometer. In major loops (|Hvert|=10 kOe), the reduced remanence-to-saturation ratio mr=Mr/Ms and the coercivity Hc measured on all studied materials appear to be related by an almost linear law of the type mr?1/3 (?Hc/kT), ? being the average magnetic moment on Co particles. A similar relation is also observed on minor symmetrical loops (100 Oe?|Hvert|?9 kOe). The observed results are accounted for by a model which considers the hysteresis as originating by magnetic interactions among nearly superparamagnetic Co particles.

Allia, P.; Coisson, M.; Tiberto, P.; Vinai, F.; Knobel, M.

1999-04-01

67

Small hysteresis and high energy storage power of antiferroelectric ceramics  

NASA Astrophysics Data System (ADS)

In this paper, modified Pb(Zr,Ti)O3(PZT) antiferroelectric (AFE) ceramics system was investigated by traditional solid state method. It was observed that the effect of different contents of Zr/Sn, Zr/Ti on modified PZT antiferroelectrics. With increasing Zr/Sn content, the EAFE (electric field of AFE phase to ferroelectric (FE) phase) value was enlarged. The phase switch field was reduced from FE to AFE (EFA). The hysteresis loops were changed from "slanted" to "square"-types. With increasing Zr/Ti concentrate, the EAFE value, and also the EFA was enlarged, while the hysteresis switch ?E was reduced. The hysteresis loops was from "square" to "slanted"-types. The samples with square hysteresis loops are suitable for energy storage capacitor applications, the composition of ceramics was Pb0.97La0.02(Zr0.90Sn0.05Ti0.05)O3, which have the largest energy storage density 4.426J/cm3 at 227 kV/cm, and ?E was 80 kV/cm, energy efficient ? was about 0.612.

Wang, Jinfei; Yang, Tongqing; Chen, Shengchen; Yao, Xi

2014-09-01

68

A simple model of hysteresis behavior using spreadsheet analysis  

NASA Astrophysics Data System (ADS)

Hysteresis loops occur in many scientific and technical problems, especially as field dependent magnetization of ferromagnetic materials, but also as stress-strain-curves of materials measured by tensile tests including thermal effects, liquid-solid phase transitions, in cell biology or economics. While several mathematical models exist which aim to calculate hysteresis energies and other parameters, here we offer a simple model for a general hysteretic system, showing different hysteresis loops depending on the defined parameters. The calculation which is based on basic spreadsheet analysis plus an easy macro code can be used by students to understand how these systems work and how the parameters influence the reactions of the system on an external field. Importantly, in the step-by-step mode, each change of the system state, compared to the last step, becomes visible. The simple program can be developed further by several changes and additions, enabling the building of a tool which is capable of answering real physical questions in the broad field of magnetism as well as in other scientific areas, in which similar hysteresis loops occur.

Ehrmann, A.; Blachowicz, T.

2015-01-01

69

The frequency-dependent Jiles-Atherton hysteresis model  

NASA Astrophysics Data System (ADS)

An extension of the Jiles-Atherton (J-A) magnetic hysteresis model is proposed in the paper. The physical J-A model has been substituted with the specially chosen mathematical Chua model. The proposed model produces identical results to those of the original J-A model for the static magnetic hysteresis loop. The new model permits the inclusion of a wide variety of additional effects observed for ferromagnetic materials without invalidating the well-known and broadly used J-A model parameters. Thus, it is possible to effectively model phenomena, whose detailed physical model would require complex mathematical calculations.

Malczyk, Robert; Izydorczyk, Jacek

2015-04-01

70

Hysteresis and nonequilibrium work theorem for DNA unzipping  

NASA Astrophysics Data System (ADS)

We study by using Monte Carlo simulations the hysteresis in unzipping and rezipping of a double stranded DNA (dsDNA) by pulling its strands in opposite directions in the fixed force ensemble. The force is increased at a constant rate from an initial value g0 to some maximum value gm that lies above the phase boundary and then decreased back again to g0. We observed hysteresis during a complete cycle of unzipping and rezipping. We obtained probability distributions of work performed over a cycle of unzipping and rezipping for various pulling rates. The mean of the distribution is found to be close (the difference being within 10%, except for very fast pulling) to the area of the hysteresis loop. We extract the equilibrium force versus separation isotherm by using the work theorem on repeated nonequilibrium force measurements. Our method is capable of reproducing the equilibrium and the nonequilibrium force-separation isotherms for the spontaneous rezipping of dsDNA.

Kapri, Rajeev

2012-10-01

71

Hysteresis modeling in ballistic carbon nanotube field-effect transistors  

PubMed Central

Theoretical models are adapted to describe the hysteresis effects seen in the electrical characteristics of carbon nanotube field-effect transistors. The ballistic transport model describes the contributions of conduction energy sub-bands over carbon nanotube field-effect transistor drain current as a function of drain-source and gate-source voltages as well as other physical parameters of the device. The limiting-loop proximity model, originally developed to understand magnetic hysteresis, is also utilized in this work. The curves obtained from our developed model corroborate well with the experimentally derived hysteretic behavior of the transistors. Modeling the hysteresis behavior will enable designers to reliably use these effects in both analog and memory applications. PMID:25187698

Liu, Yian; Moura, Mateus S; Costa, Ademir J; de Almeida, Luiz Alberto L; Paranjape, Makarand; Fontana, Marcio

2014-01-01

72

Mach, methodology, hysteresis and economics  

NASA Astrophysics Data System (ADS)

This methodological note examines the epistemological foundations of hysteresis with particular reference to applications to economic systems. The economy principles of Ernst Mach are advocated and used in this assessment.

Cross, R.

2008-11-01

73

The New P.E.  

ERIC Educational Resources Information Center

Marana Middle School in Tucson, Ariz., scrapped its traditional P.E. program that emphasized team sports and shifted to a program that focuses on lifetime fitness, student choice in activities, and nutrition and health education. The program also includes student leadership development and informal community service. As a result, Marana students…

Vandertie, Joan; Corner, Amy B.; Corner, Kevin J.

2012-01-01

74

Stress dependence and effect of plastic deformation on magnetic hysteresis and anhysteretic magnetization of FeNi32% films  

Microsoft Academic Search

The magnetic hysteresis and anhysteretic magnetization of FeNi32% films were investigated as a function of isotropic stress. The magnetostriction contribution to dc magnetization under elastic stress and the effect of the plastic strain on the hysteresis loops are discussed. Also, a role of the plastic deformation interrelated with the elastic stress in the magnetization process is established. An experimental system

P. Finkel; S. Lofland

2007-01-01

75

Hysteresis of primary cosmic rays associated with Forbush decreases  

Microsoft Academic Search

A variation of quasi-steady primary-cosmic-ray intensities during Forbush events is reported which was detected in data obtained by a neutron monitor, the OGO 1 and 3 ion chambers, and daily observations of upper-atmosphere intensities recorded with standardized Geiger-Mueller counters. A regression plot of the intensities of high- and low-rigidity primaries is found to exhibit hysteresis loops during Forbush decreases, indicating

R. S. Rajan

1976-01-01

76

Barkhausen discontinuities and hysteresis of ferromagnetics: New stochastic approach  

SciTech Connect

The magnetization of ferromagnetic material is considered as periodically inhomogeneous Markov process. The theory assumes both statistically independent and correlated Barkhausen discontinuities. The model, based on the chain evolution-type process theory, assumes that the domain structure of a ferromagnet passes successively the steps of: linear growing, exponential acceleration and domains annihilation to zero density at magnetic saturation. The solution of stochastic differential Kolmogorov equation enables the hysteresis loop calculus.

Vengrinovich, Valeriy, E-mail: veng@iaph.bas-net.by [Institute of Applied Physics of the Belarus Academy of Sciences 220072, Akademicheskaya street 16, Minsk (Belarus)

2014-02-18

77

Proton intercalation hysteresis in charging and discharging nickel hydroxide electrodes  

Microsoft Academic Search

A reproducible hysteresis in charge-discharge cycling of thin-film (10--40 nm thickness) electroprecipitated nickel hydroxide electrodes was quantified. Thin-film electrodes were prepared both with and without coprecipitated cobalt hydroxide, a common additive to nickel hydroxide electrodes. The ascending and descending branches of the hysteretic loop were determined. Experimental data were gathered using commonly employed techniques to capture electrode behavior on short-

Kathryn Podolske Ta; J. Newman

1999-01-01

78

Domain-wall motion in random potential and hysteresis modeling  

SciTech Connect

Two different approaches to hysteresis modeling are compared using a common ground based on energy relations, defined in terms of dissipated and stored energy. Using the Preisach model and assuming that magnetization is mainly due to domain-wall motion, one can derive the expression of magnetization along a major loop typical of the Jiles{endash}Atherton model and then extend its validity to cases where mean-field effects and reversible contributions are present. {copyright} {ital 1998 American Institute of Physics.}

Pasquale, M.; Basso, V.; Bertotti, G. [IEN Galileo Ferraris and INFM C. so M. DAzeglio42, 10125Torino (Italy)] [IEN Galileo Ferraris and INFM C. so M. DAzeglio42, 10125Torino (Italy); Jiles, D.C.; Bi, Y. [Ames Laboratory, Iowa State University, 50011Ames, Iowa (United States)] [Ames Laboratory, Iowa State University, 50011Ames, Iowa (United States)

1998-06-01

79

Rate-dependent light-induced thermal hysteresis of [Fe(PM-BiA)2(NCS)2] spin transition complex  

NASA Astrophysics Data System (ADS)

The light-induced bistability under permanent irradiation (LITH: light-induced thermal hysteresis), due to the competition between light irradiation and self-accelerated relaxation, shows crucially rate-dependent hysteresis. Major and minor hysteresis loops for [Fe(PM-BiA)2(NCS)2] spin crossover compound have been measured. Using appropriate master equations, distribution data from the first-order reversal curves diagrams of the purely thermal hysteresis, and parameter values previously derived from relaxation curves, we could simulate the LITH experimental data. The tunneling contribution to the relaxation rate revealed to be a key factor for the final agreement.

Enachescu, Cristian; Tanasa, Radu; Stancu, Alexandru; Chastanet, Guillaume; Létard, Jean-François; Linares, Jorge; Varret, François

2006-04-01

80

Adsorption-desorption Hysteresis of Kr and Xe on the Surface of an Ag Single Crystal  

NASA Astrophysics Data System (ADS)

The isotherms and the isobars of krypton and xenon physisorbed on a silver single crystal surface were investigated by ellipsometric observation of the amount of adsorption. It was found that they showed a hysteresis in an adsorption-desorption loop for both the first and the second layer condensations. Careful examination of the effect of instability of an equilibrium pressure and a substrate temperature during the measurement revealed that they were not responsible for hysteresis. The observed hysteresis is very likely to be intrinsic one though its origin and mechanism are unknown.

Hamada, Nozomu; Moto, Shuichi; Nakazawa, Jun; Miura, Takashi; Arakawa, Ichiro

81

Theory of molecular hysteresis switch  

NASA Astrophysics Data System (ADS)

Molecular hysteresis switching has been recently observed in a series of experiments that measured the I-V spectrum of bipyridyl-dinitro oligophenylene-ethylene dithiol (BPDN) based molecular devices [1]. The experimental observations clearly show the presence of Coulomb blockade in single organic molecules that is responsible for the voltage-induced switching. We present the theory of the hysteresis switch which explains the non-linear hysteresis I-V characteristics based on the mechanisms of Coulomb blockade and the existence of two different molecular conformations of neutral and charged states of the molecule. [1] A.S. Blum, J.G. Kushmerick, D.P. Long, C.H. Patterson, J.C. Yang, J.C. Henderson, Y.X. Yao, J.M. Tour, R. Shashidhar, and B.R. Ratna, ``Molecularly inherent voltage-controlled conductance switching'' , Nature Materials 4, 167 (2005).

Kozhushner, Mortko; Oleynik, Ivan

2006-03-01

82

Size dependent thermal hysteresis in spin crossover nanoparticles reflected within a Monte Carlo based Ising-like model  

NASA Astrophysics Data System (ADS)

Spin crossover compounds are photo-magnetic bistable molecular magnets with two states in thermodynamic competition: the diamagnetic low-spin state and paramagnetic high-spin state. The thermal transition between the two states is often accompanied by a wide hysteresis, premise for possible application of these materials as recording media. In this paper we study the influence of the system's size on the thermal hysteresis loops using Monte Carlo simulations based on an Arrhenius dynamics applied for an Ising like model with long- and short-range interactions. We show that using appropriate boundary conditions it is possible to reproduce both the drop of hysteresis width with decreasing particle size, the hysteresis shift towards lower temperatures and the incomplete transition, as in the available experimental data. The case of larger systems composed by several sublattices is equally treated reproducing the shrinkage of the hysteresis loop's width experimentally observed.

Atitoaie, Alexandru; Tanasa, Radu; Enachescu, Cristian

2012-04-01

83

Hysteresis Responses of Evapotranspiration to Meteorological Factors at a Diel Timescale: Patterns and Causes  

PubMed Central

Evapotranspiration (ET) is an important component of the water cycle in terrestrial ecosystems. Understanding the ways in which ET changes with meteorological factors is central to a better understanding of ecological and hydrological processes. In this study, we used eddy covariance measurements of ET from a typical alpine shrubland meadow ecosystem in China to investigate the hysteresis response of ET to environmental variables including air temperature (Ta), vapor pressure deficit (VPD) and net radiation (Rn) at a diel timescale. Meanwhile, the simulated ET by Priestly-Taylor equation was used to interpret the measured ET under well-watered conditions. Pronounced hysteresis was observed in both Ta and VPD response curves of ET. At a similar Ta and VPD, ET was always significantly depressed in the afternoon compared with the morning. But the hysteresis response of ET to Rn was not evident. Similar hysteresis patterns were also observed in the Ta/VPD response curves of simulated ET. The magnitudes of the measured and simulated hysteresis loops showed similar seasonal variation, with relatively smaller values occurring from May to September, which agreed well with the lifetime of plants and the period of rainy season at this site. About 62% and 23% of changes in the strength of measured ET-Ta and ET-VPD loops could be explained by the changes in the strength of simulated loops, respectively. Thus, the time lag between Rn and Ta/VPD is the most important factor generating and modulating the ET-Ta/VPD hysteresis, but plants and water status also contribute to the hysteresis response of ET. Our research confirmed the different hysteresis in the responses of ET to meteorological factors and proved the vital role of Rn in driving the diel course of ET. PMID:24896829

Zheng, Han; Wang, Qiufeng; Zhu, Xianjin; Li, Yingnian; Yu, Guirui

2014-01-01

84

Hysteresis responses of evapotranspiration to meteorological factors at a diel timescale: patterns and causes.  

PubMed

Evapotranspiration (ET) is an important component of the water cycle in terrestrial ecosystems. Understanding the ways in which ET changes with meteorological factors is central to a better understanding of ecological and hydrological processes. In this study, we used eddy covariance measurements of ET from a typical alpine shrubland meadow ecosystem in China to investigate the hysteresis response of ET to environmental variables including air temperature (Ta), vapor pressure deficit (VPD) and net radiation (Rn) at a diel timescale. Meanwhile, the simulated ET by Priestly-Taylor equation was used to interpret the measured ET under well-watered conditions. Pronounced hysteresis was observed in both Ta and VPD response curves of ET. At a similar Ta and VPD, ET was always significantly depressed in the afternoon compared with the morning. But the hysteresis response of ET to Rn was not evident. Similar hysteresis patterns were also observed in the Ta/VPD response curves of simulated ET. The magnitudes of the measured and simulated hysteresis loops showed similar seasonal variation, with relatively smaller values occurring from May to September, which agreed well with the lifetime of plants and the period of rainy season at this site. About 62% and 23% of changes in the strength of measured ET-Ta and ET-VPD loops could be explained by the changes in the strength of simulated loops, respectively. Thus, the time lag between Rn and Ta/VPD is the most important factor generating and modulating the ET-Ta/VPD hysteresis, but plants and water status also contribute to the hysteresis response of ET. Our research confirmed the different hysteresis in the responses of ET to meteorological factors and proved the vital role of Rn in driving the diel course of ET. PMID:24896829

Zheng, Han; Wang, Qiufeng; Zhu, Xianjin; Li, Yingnian; Yu, Guirui

2014-01-01

85

Proton intercalation hysteresis in charging and discharging nickel hydroxide electrodes  

SciTech Connect

A reproducible hysteresis in charge-discharge cycling of thin-film (10--40 nm thickness) electroprecipitated nickel hydroxide electrodes was quantified. Thin-film electrodes were prepared both with and without coprecipitated cobalt hydroxide, a common additive to nickel hydroxide electrodes. The ascending and descending branches of the hysteretic loop were determined. Experimental data were gathered using commonly employed techniques to capture electrode behavior on short- and long-time scales. Cyclic voltammetry and galvanostatic discharge experiments were performed, and a macroscopic model of the nickel hydroxide solid material was constructed and used to interpret the simultaneous mass-transfer, kinetic, and thermodynamic phenomena occurring at the nickel hydroxide intercalation electrode. The persistent hysteresis exhibited by these thin-film electrodes cannot be due only to solid-state mass-transfer limitations. Agreement between calculated and experimental results is achieved with treatment of the hysteresis effect as a permanent, thermodynamic quantity. The numerical model may be applied to most rechargeable cells and is especially suited for systems which exhibit a permanent hysteretic loop or in which side reactions are prevalent. Model results agree with current and potential waveforms gathered from experiments performed with nickel hydroxide thin-film electrodes.

Ta, K.P.; Newman, J.

1999-08-01

86

Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes  

NASA Astrophysics Data System (ADS)

The Gd5Ge2Si2 alloy and the off-stoichiometric Ni50Mn35In15 Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd5Ge2Si2 and Ni50Mn35In15 alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis.

Provenzano, Virgil; Della Torre, Edward; Bennett, Lawrence H.; ElBidweihy, Hatem

2014-02-01

87

Hysteresis and compensation behaviors of spin-3/2 cylindrical Ising nanotube system  

SciTech Connect

The hysteresis and compensation behaviors of the spin-3/2 cylindrical Ising nanotube system are studied within the framework of the effective-field theory with correlations. The effects of the Hamiltonian parameters are investigated on the magnetic and thermodynamic quantities, such as the total magnetization, hysteresis curves, and compensation behaviors of the system. Depending on the Hamiltonian parameters, some characteristic hysteresis behaviors are found, such as the existence of double and triple hysteresis loops. According to Néel classification nomenclature, the system displays Q-, R-, P-, N-, M-, and S- types of compensation behaviors for the appropriate values of the system parameters. We also compare our results with some recently published theoretical and experimental works and find a qualitatively good agreement.

Kocakaplan, Yusuf [Graduate School of Natural and Applied Sciences, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa, E-mail: keskin@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2014-09-07

88

Hysteresis in Audiovisual Synchrony Perception  

PubMed Central

The effect of stimulation history on the perception of a current event can yield two opposite effects, namely: adaptation or hysteresis. The perception of the current event thus goes in the opposite or in the same direction as prior stimulation, respectively. In audiovisual (AV) synchrony perception, adaptation effects have primarily been reported. Here, we tested if perceptual hysteresis could also be observed over adaptation in AV timing perception by varying different experimental conditions. Participants were asked to judge the synchrony of the last (test) stimulus of an AV sequence with either constant or gradually changing AV intervals (constant and dynamic condition, respectively). The onset timing of the test stimulus could be cued or not (prospective vs. retrospective condition, respectively). We observed hysteretic effects for AV synchrony judgments in the retrospective condition that were independent of the constant or dynamic nature of the adapted stimuli; these effects disappeared in the prospective condition. The present findings suggest that knowing when to estimate a stimulus property has a crucial impact on perceptual simultaneity judgments. Our results extend beyond AV timing perception, and have strong implications regarding the comparative study of hysteresis and adaptation phenomena. PMID:25774653

van Wassenhove, Virginie

2015-01-01

89

arXiv:1406.6845v1[cond-mat.dis-nn]26Jun2014 Avalanches and hysteresis in frustrated superconductors and XY-spin-glasses  

E-print Network

arXiv:1406.6845v1[cond-mat.dis-nn]26Jun2014 Avalanches and hysteresis in frustrated superconductors. 38, 01187 Dresden, Germany (Dated: June 27, 2014) We study avalanches along the hysteresis loop by the softest mode of the inverse susceptibility matrix becoming unstable, which induces an avalanche of phase

Müller, Markus

90

Ionically-mediated electromechanical hysteresis in transition metal oxides  

SciTech Connect

Electromechanical activity, remanent polarization states, and hysteresis loops in paraelectric TiO2 and SrTiO3 are observed. The coupling between the ionic dynamics and incipient ferroelectricity in these materials is analyzed using extended Ginsburg Landau Devonshire (GLD) theory. The possible origins of electromechanical coupling including ionic dynamics, surface-charge induced electrostriction, and ionically-induced ferroelectricity are identified. For the latter, the ionic contribution can change the sign of first order GLD expansion coefficient, rendering material effectively ferroelectric. These studies provide possible explanation for ferroelectric-like behavior in centrosymmetric transition metal oxides.

Kim, Yunseok [ORNL] [ORNL; Kumar, Amit [ORNL] [ORNL; Jesse, Stephen [ORNL] [ORNL; Kalinin, Sergei V [ORNL] [ORNL

2012-01-01

91

Capillary condensation, invasion percolation, hysteresis, and discrete memory  

SciTech Connect

A model of the capillary condensation process, i.e., of adsorption-desorption isotherms, having only pore-pore interactions is constructed. The model yields (1) hysteretic isotherms, (2) invasion percolation on desorption, and (3) hysteresis with discrete memory for interior chemical potential loops. All of these features are seen in experiment. The model is compared to a model with no pore-pore interactions (the Preisach model) and to a related model of interacting pore systems (the random field Ising model). The capillary condensation model differs from both. {copyright} {ital 1996 The American Physical Society.}

Guyer, R.A. [Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003 (United States)] [Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003 (United States); McCall, K.R. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)] [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

1996-07-01

92

High hysteresis in a homogeneous metallic glass  

NASA Astrophysics Data System (ADS)

In this article, we demonstrate high hysteresis in a well characterized homogeneous Tb-Al glass which contained no crystallites or crystalline embryos as verified using conventional and synchrotron diffraction, neutron diffraction, and direct observation in the transmission electron microscope. At low temperature (2 K), the metallic glass structure exhibited intrinsic coercivities approaching 23 kOe and high isotropic energy products of 12.4 MGOe. After crystallization into a three-phase nanoscale structure, the hard magnetic properties were found to be far inferior to that obtainable in the glass structure. From the well defined intrinsic magnetic properties (Msat,Tc), it is clear that the glass contains one or more types of well defined associations (i.e., clusters) and that these associations lead to ferromagnetic coupling/ordering. From the large random magnetic anisotropy, it is probable that the domain size is much larger than the structural cluster size. The measured single-phase loop shapes and the development of high coercivity in the glass state can be explained by an "exchange bias" mechanism resulting in a near perfect distribution of "fragile" pinning centers.

Branagan, D. J.; Meacham, B. E.; McCallum, R. W.; Dennis, K. W.; Kramer, M. J.

2003-05-01

93

Asymmetric-hysteresis compensation in piezoelectric actuators  

NASA Astrophysics Data System (ADS)

The advantages of using piezoelectric actuators in ultra-precision applications are often impaired by nonlinear effects, in particular hysteresis, which may lead to positioning uncertainties of up to 15% of the actuator's stroke. Model-based compensation strategies are often prescribed in order to overcome this limitation and achieve better dynamical accuracy. This comes, however, at the expense of increasing identification and implementation complexity, especially when hysteresis is of the asymmetric type, such as prevalent in hard piezoceramic materials. This paper proposes a new compensation strategy based upon (i) treating hysteresis as being separate from other dynamical effects and (ii) formulating a new, simplified model to deal with asymmetric hysteresis, based on applying a linear operator to the conventional hysteresis models. After developing the theoretical background of the compensation strategy, the accuracy improvement due to the new hysteresis-compensation method is demonstrated experimentally.

Aguirre, Gorka; Janssens, Thierry; Van Brussel, Hendrik; Al-Bender, Farid

2012-07-01

94

Contact angle hysteresis on fluoropolymer surfaces.  

PubMed

Contact angle hysteresis of liquids with different molecular and geometrical properties on high quality films of four fluoropolymers was studied. A number of different causes are identified for hysteresis. With n-alkanes as probe liquids, contact angle hysteresis is found to be strongly related to the configuration of polymer chains. The largest hysteresis is obtained with amorphous polymers whereas the smallest hysteresis occurs for polymers with ordered molecular chains. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Correlation of contact angle hysteresis with the size of n-alkane molecules supports this conclusion. On the films of two amorphous fluoropolymers with different molecular configurations, contact angle hysteresis of one and the same liquid with "bulky" molecules is shown to be quite different. On the surfaces of Teflon AF 1600, with stiff molecular chains, the receding angles of the probe liquids are independent of contact time between solid and liquid and similar hysteresis is obtained for all the liquids. Retention of liquid molecules on the solid surface is proposed as the most likely cause of hysteresis in these systems. On the other hand, with EGC-1700 films that consist of flexible chains, the receding angles are strongly time-dependent and the hysteresis is large. Contact angle hysteresis increases even further when liquids with strong dipolar intermolecular forces are used. In this case, major reorganization of EGC-1700 chains due to contact with the test liquids is suggested as the cause. The effect of rate of motion of the three-phase line on the advancing and receding contact angles, and therefore contact angle hysteresis, is investigated. For low viscous liquids, contact angles are independent of the drop front velocity up to approximately 10 mm/min. This agrees with the results of an earlier study that showed that the rate-dependence of the contact angles is an issue only for liquids with high viscosity. PMID:17537391

Tavana, H; Jehnichen, D; Grundke, K; Hair, M L; Neumann, A W

2007-10-31

95

Relationships between hysteresis measurements and the constituent properties of ceramic matrix composites. 2: Experimental studies on unidirectional materials  

Microsoft Academic Search

The use of hysteresis loop measurements for assessing the constituent properties of unidirectional CMCs is evaluated, using basic theory described in a companion paper. Results are obtained on SiC\\/CAS and SiC\\/SiC composites. These materials exhibit very different hysteresis characteristics, reflected in differences in sliding stress, Ï, and debond energy, Î{sub i}. These interface properties are manifest in the respective tensile

Jean-Marc Domergue; Emmanuel Vagaggini; Anthony G. Evans

1995-01-01

96

Hysteresis in the conductance of asymmetrically biased GaAs quantum point contacts with in-plane side gates  

NASA Astrophysics Data System (ADS)

We have observed hysteresis between the forward and reverse sweeps of a common mode bias applied to the two in-plane side gates of an asymmetrically biased GaAs quantum point contact (QPC). The size of the hysteresis loop increases with the amount of bias asymmetry ?Vg between the two side gates and depends on the polarity of ?Vg. Our results are in qualitative agreement with Non-Equilibrium Green's Function simulations including the effects of dangling bond scattering on the sidewalls of the QPC. It is argued that hysteresis may constitute another indirect proof of spontaneous spin polarization in the narrow portion of the QPC.

Bhandari, N.; Dutta, M.; Charles, J.; Cahay, M.; Newrock, R. S.

2013-07-01

97

From the Cover: Hysteresis drives cell-cycle transitions in Xenopus laevis egg extracts  

NASA Astrophysics Data System (ADS)

Cells progressing through the cell cycle must commit irreversibly to mitosis without slipping back to interphase before properly segregating their chromosomes. A mathematical model of cell-cycle progression in cell-free egg extracts from frog predicts that irreversible transitions into and out of mitosis are driven by hysteresis in the molecular control system. Hysteresis refers to toggle-like switching behavior in a dynamical system. In the mathematical model, the toggle switch is created by positive feedback in the phosphorylation reactions controlling the activity of Cdc2, a protein kinase bound to its regulatory subunit, cyclin B. To determine whether hysteresis underlies entry into and exit from mitosis in cell-free egg extracts, we tested three predictions of the Novak-Tyson model. (i) The minimal concentration of cyclin B necessary to drive an interphase extract into mitosis is distinctly higher than the minimal concentration necessary to hold a mitotic extract in mitosis, evidence for hysteresis. (ii) Unreplicated DNA elevates the cyclin threshold for Cdc2 activation, indication that checkpoints operate by enlarging the hysteresis loop. (iii) A dramatic "slowing down" in the rate of Cdc2 activation is detected at concentrations of cyclin B marginally above the activation threshold. All three predictions were validated. These observations confirm hysteresis as the driving force for cell-cycle transitions into and out of mitosis.

Sha, Wei; Moore, Jonathan; Chen, Katherine; Lassaletta, Antonio D.; Yi, Chung-Seon; Tyson, John J.; Sible, Jill C.

2003-02-01

98

Magnetoimpedance hysteresis in amorphous microwires induced by core-shell interaction  

NASA Astrophysics Data System (ADS)

We report on magneto-impedance (MI) hysteresis at MHz and GHz frequencies in amorphous microwires subject to a sufficiently high applied axial magnetic field HE. We show that this hysteresis originates from the magnetic hysteresis of the inner core which biases the outer shell causing a shift of the MI curve along the HE axis. Combined experiments (longitudinal and off-diagonal MI Z(HE), hysteresis loops M(HE) by vibrating sample magnetometer, and induction method) reveal the details of the magnetization reversal process in these microwires: Partial field dependencies Z(HE) and M(HE) are shown to be practically anhysteretic but shifted to the left or to the right about the origin by a residual magnetic field of the inner core HC. This shift can vary in the range from -35 to +35 A/m, depending on the magnetic history of the sample. We demonstrate that the hysteresis can be suppressed by application of a high enough axial magnetic field that saturates the magnetization of the inner core. A potential application of this hysteresis for memory devices is also proposed.

Ipatov, M.; Zhukova, V.; Gonzalez, J.; Zhukov, A.

2014-09-01

99

A neural network for incorporating the thermal effect on the magnetic hysteresis of the 3F3 material using the Jiles-Atherton model  

NASA Astrophysics Data System (ADS)

The present paper deals with the temperature dependent modeling approach for the generation of hysteresis loops of ferromagnetic materials. The physical model is developed to study the effect of temperature on the magnetic hysteresis loop using the Jiles-Atherton (J-A) model. The thermal effects were incorporated through temperature dependent hysteresis parameters of JA model. The temperature-dependent J-A model was validated by measurements made on the ferrite material. The results of proposed model were in good agreement with the measurements.

Nouicer, A.; Nouicer, E.; Feliachi, Mouloud

2015-01-01

100

MATHEMATICAL MODELS OF HYSTERESIS (DYNAMIC PROBLEMS IN HYSTERESIS)  

SciTech Connect

This research has further advanced the current state of the art in the areas of dynamic aspects of hysteresis and nonlinear large scale magnetization dynamics. The results of this research will find important engineering applications in the areas of magnetic data storage technology and the emerging technology of “spintronics”. Our research efforts have been focused on the following tasks: • Study of fast (pulse) precessional switching of magnetization in magnetic materials. • Analysis of critical fields and critical angles for precessional switching of magnetization. • Development of inverse problem approach to the design of magnetic field pulses for precessional switching of magnetization. • Study of magnetization dynamics induced by spin polarized current injection. • Construction of complete stability diagrams for spin polarized current induced magnetization dynamics. • Development of the averaging technique for the analysis of the slow time scale magnetization dynamics. • Study of thermal effects on magnetization dynamics by using the theory of stochastic processes on graphs.

Professor Isaak Mayergoyz

2006-08-21

101

Modeling the influence of varying magnetic properties in soft magnetic materials on the hysteresis shape using the flux tube approach  

NASA Astrophysics Data System (ADS)

Magnetic properties can vary significantly inside soft magnetic steel sheets (SMSSs), both due to mechanical stresses and structural changes originating from different manufacturing processes. The integral consideration, i.e. averaging these effects over the SMSS, leads to a strong simplification of the underlying mechanisms. Such simplification is often inadequate when considering the influence of the varying magnetic properties on the hysteresis loop shape and its dynamic behavior. This paper presents a new approach to model irregular hysteresis loops of non-oriented SMSSs using the flux tube approach, where the SMSS is divided into several flux tubes having different magnetic properties. This enables to model non-homogeneous distributions of the magnetic flux and irregular hysteresis loops subject to varying magnetic properties.

Petrun, M.; Steentjes, S.; Hameyer, K.; Dolinar, D.

2015-05-01

102

Control of hysteresis: theory and experimental results  

Microsoft Academic Search

Hysteresis in smart materials hinders the wider applicability of such materials in actuators. In this paper, a systematic approach for coping with hysteresis is presented. The method is illustrated through the example of controlling a commercially available magnetostrictive actuator. We utilize the low-dimensional model for the magnetostrictive actuator that was developed in earlier work. For low frequency inputs, the model

Xiaobo Tan; P. S. Krishnaprasad; Wright-Patterson AF

103

The hysteresis phenomenon of the field emission from the graphene film  

NASA Astrophysics Data System (ADS)

A cycle-testing of field emission behavior was carried out for graphene film prepared by electrophoresis deposition followed by annealing at 700 °C in argon atmosphere. The result shows that the graphene film displays a stable field emission characteristic after a period of conditioning. Also, it is interesting that the field emission hysteresis takes place when the film is measured in loops of rised and falled voltages. The possible physical mechanism of this hysteresis phenomenon may be relevant to the desorption/adsorption effect of gas molecules.

Chen, Jiangtao; Li, Jun; Yang, Juan; Yan, Xingbin; Tay, Beng-Kang; Xue, Qunji

2011-10-01

104

Hysteresis and coercivity of hematite  

NASA Astrophysics Data System (ADS)

room-temperature hysteresis, 14 submicron hematites (0.12-0.45 µm) had large coercive forces Hc (150-350 mT), while 22 natural 1-5.5 mm hematite crystals had Hc = 0.8-23 mT (basal-plane measurements). Single-domain (SD) and multidomain (MD) hematites owe their high Hc mainly to magnetoelastic anisotropy, caused in fine particles by internal strains and in large crystals by defects like dislocations, with a smaller contribution by triaxial magnetocrystalline anisotropy. A strong correlation between Hc and the defect moment Md measured below hematite's Morin transition also favors magnetoelastic control. Saturation remanence/saturation magnetization ratios Mrs/Ms and coercivity ratios Hcr/Hc (Hcr is remanent coercive force) are distinctive: Mrs/Ms = 0.5-0.9, Hcr/Hc = 1.02-1.17 for MD hematites; Mrs/Ms = 0.5-0.7, Hcr/Hc = 1.45-1.62 for SD hematites. In high-temperature (20-690°C) hysteresis, Hc(T) ~ Ms(T) to a power 1.8-2.4 above 385°C. Magnetoelastic wall pinning by crystal defects is thus more likely than control by domain nucleation which depends on magnetocrystalline anisotropy. Our results compare well with existing Hc vs. crystal size d data. A suggested peak in Hc around 15 µm and a proposed slope change around 100 µm are both questionable. Using only near-saturation data, Hc varies continuously as d-0.61 from ?0.1 µm to 2 mm. The SD threshold size d0 may be >15 µm but there is no strong evidence that d0 ?100 µm. Direct domain observations are needed to settle the question. Augmented data sets for Hc and Mrs vs. d show that SD hematite is increasingly affected by thermal fluctuations below ?0.3 µm and generally confirm a superparamagnetic threshold size ds of 0.025-0.03 µm.

Ã-zdemir, Ã.-zden; Dunlop, David J.

2014-04-01

105

Corneal hysteresis and its relevance to glaucoma  

PubMed Central

Purpose of review Glaucoma is a leading cause of irreversible blindness worldwide. It is estimated that roughly 60.5 million people had glaucoma in 2010 and that this number is increasing. Many patients continue to lose vision despite apparent disease control according to traditional risk factors. The purpose of this review is to discuss the recent findings with regard to corneal hysteresis, a variable that is thought to be associated with the risk and progression of glaucoma. Recent findings Low corneal hysteresis is associated with optic nerve and visual field damage in glaucoma and the risk of structural and functional glaucoma progression. In addition, hysteresis may enhance intraocular pressure (IOP) interpretation: low corneal hysteresis is associated with a larger magnitude of IOP reduction following various glaucoma therapies. Corneal hysteresis is dynamic and may increase in eyes after IOP-lowering interventions are implemented. Summary It is widely accepted that central corneal thickness is a predictive factor for the risk of glaucoma progression. Recent evidence shows that corneal hysteresis also provides valuable information for several aspects of glaucoma management. In fact, corneal hysteresis may be more strongly associated with glaucoma presence, risk of progression, and effectiveness of glaucoma treatments than central corneal thickness. PMID:25611166

Deol, Madhvi; Taylor, David A.; Radcliffe, Nathan M.

2015-01-01

106

Mechanisms of magnetic and temperature hysteresis in ErFeO3 and TmFeO3 single crystals  

NASA Astrophysics Data System (ADS)

Magnetic hysteresis is studied in the orthoferrites ErFeO3 and TmFeO3 using the single crystal samples of millimeter dimensions. It is shown that in both materials one observes a temperature transition manifesting itself through the temperature hysteresis of the magnetic moment and a peculiar temperature evolution of the field hysteresis loop shapes near this transition. Experiments rule out the hypothesis that the ordering of the orthoferrite's rare-earth magnetic moments plays an important role in these phenomena. The hysteresis curves can be explained by a few-domain magnetic state of the samples that results from the weak ferromagnetism of the orthoferrites. The phenomenon is generic for weak ferromagnets with temperature dependent magnetization. A large characteristic magnetic length makes the behavior of the relatively big samples analogous to that observed in the nanosize samples of strong ferromagnets.

Tsymbal, L. T.; Bazaliy, Ya. B.; Kakazei, G. N.; Vasiliev, S. V.

2010-10-01

107

Analysis of hunting in Synchronous Hysteresis Motor  

E-print Network

The Synchronous Hysteresis Motor has an inherent instability when it is used to drive a gyroscope wheel. The motor ideally should spin at a constant angular velocity, but it instead sporadically oscillates about synchronous ...

Truong, Cang Kim, 1979-

2004-01-01

108

Direct hysteresis measurements on ferroelectret films by means of a modified Sawyer-Tower circuit  

NASA Astrophysics Data System (ADS)

Ferro- and piezo-electrets are non-polar polymer foams or film systems with internally charged cavities. Since their invention more than two decades ago, ferroelectrets have become a welcome addition to the range of piezo-, pyro-, and ferro-electric materials available for device applications. A polarization-versus-electric-field hysteresis is an essential feature of a ferroelectric material and may also be used for determining some of its main properties. Here, a modified Sawyer-Tower circuit and a combination of unipolar and bipolar voltage waveforms are employed to record hysteresis curves on cellular-foam polypropylene ferroelectret films and on tubular-channel fluoroethylenepropylene copolymer ferroelectret film systems. Internal dielectric barrier discharges (DBDs) are required for depositing the internal charges in ferroelectrets. The true amount of charge transferred during the internal DBDs is obtained from voltage measurements on a standard capacitor connected in series with the sample, but with a much larger capacitance than the sample. Another standard capacitor with a much smaller capacitance—which is, however, still considerably larger than the sample capacitance—is also connected in series as a high-voltage divider protecting the electrometer against destructive breakdown. It is shown how the DBDs inside the polymer cavities lead to phenomenological hysteresis curves that cannot be distinguished from the hysteresis loops found on other ferroic materials. The physical mechanisms behind the hysteresis behavior are described and discussed.

Qiu, Xunlin; Holländer, Lars; Wirges, Werner; Gerhard, Reimund; Cury Basso, Heitor

2013-06-01

109

Equivalent Circuit Modeling of Hysteresis Motors  

SciTech Connect

We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.

Nitao, J J; Scharlemann, E T; Kirkendall, B A

2009-08-31

110

Structural hysteresis model of transmitting mechanical systems  

NASA Astrophysics Data System (ADS)

We present a structural hysteresis model which describes the dynamic behavior of transmitting mechanical systems with a hysteretic spring and damped bedstop element, both connected in series. From the application point view this approach can be used for predicting the transmitted mechanical force based only on the known kinematic excitation. Using the case study of an elastic gear transmission we show and identify a hysteresis response which multivariate behavior depends on an internal state of the bedstop motion.

Ruderman, M.; Bertram, T.

2015-02-01

111

Precision control of piezo-actuated optical deflector with nonlinearity correction based on hysteresis model  

NASA Astrophysics Data System (ADS)

The hysteresis nonlinearity of piezoelectric actuator is one of the main defects in the control of optical deflector which is widely used as a key component in adaptive optics system. In this paper, a control method combining the feedforward and feedback controllers is proposed to precisely control the deflection angle of an optical deflector. The inverse of an asymmetric Prandtl-Ishlinskii (PI) hysteresis model is utilized in the feedforward loop, and a PID controller is used in the feedback loop. Then, a tracking control experiment for the desired triangle wave was performed. From the experimental results, we can see that the response of the optical deflector is linearized and the positioning precision of optical deflector is significantly improved.

Wang, Geng; Guan, Chunlin; Zhang, Xiaojun; Zhou, Hong; Rao, Changhui

2014-04-01

112

Disorder-driven first-order phase transformations: A model for hysteresis  

SciTech Connect

Hysteresis loops in some magnetic systems are composed of small avalanches (manifesting themselves as Barkhausen pulses). Hysteresis loops in other first-order phase transitions (including some magnetic systems) often occur via one large avalanche. The transition between these two limiting cases is studied, by varying the disorder in the zero-temperature random-field Ising model. Sweeping the external field through zero at weak disorder, we get one large avalanche with small precursors and aftershocks. At strong disorder, we get a distribution of small avalanches (small Barkhausen effect). At the critical value of disorder where a macroscopic jump in the magnetization first occurs, universal power-law behavior of the magnetization and of the distribution of (Barkhausen) avalanches is found. This transition is studied by mean-field theory, perturbative expansions, and numerical simulation in three dimensions.

Dahmen, K.; Kartha, S.; Krumhansl, J.A.; Roberts, B.W.; Sethna, J.P.; Shore, J.D. (Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (United States))

1994-05-15

113

Dynamics of Phase Transitions by Hysteresis Methods I  

E-print Network

In studies of the QCD deconfining phase transition or crossover by means of heavy ion experiments, one ought to be concerned about non-equilibrium effects due to heating and cooling of the system. Motivated by this, we look at hysteresis methods to study the dynamics of phase transitions. Our systems are temperature driven through the phase transition using updating procedures in the Glauber universality class. Hysteresis calculations are presented for a number of observables, including the (internal) energy, properties of Fortuin-Kasteleyn clusters and structure functions. We test the methods for 2d Potts models, which provide a rich collection of phase transitions with a number of rigorously known properties. Comparing with equilibrium configurations we find a scenario where the dynamics of the transition leads to a spinodal decomposition which dominates the statistical properties of the configurations. One may expect an enhancement of low energy gluon production due to spinodal decomposition of the Polyakov loops, if such a scenario is realized by nature.

Bernd A. Berg; Urs M. Heller; Hildegard Meyer-Ortmanns; Alexander Velytsky

2003-10-31

114

Transport, hysteresis and avalanches in artificial spin ice systems  

SciTech Connect

We examine the hopping dynamics of an artificial spin ice system constructed from colloids on a kagome optical trap array where each trap has two possible states. By applying an external drive from an electric field which is analogous to a biasing applied magnetic field for real spin systems, we can create polarized states that obey the spin-ice rules of two spins in and one spin out at each vertex. We demonstrate that when we sweep the external drive and measure the fraction of the system that has been polarized, we can generate a hysteresis loop analogous to the hysteretic magnetization versus external magnetic field curves for real spin systems. The disorder in our system can be readily controlled by changing the barrier that must be overcome before a colloid can hop from one side of a trap to the other. For systems with no disorder, the effective spins all flip simultaneously as the biasing field is changed, while for strong disorder the hysteresis curves show a series of discontinuous jumps or avalanches similar to Barkhausen noise.

Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory; Libal, A [BABES-BOLYAI UNIV.

2010-01-01

115

Hysteresis from antiferromagnet domain-wall processes in exchange-biased systems: Magnetic defects and thermal effects  

Microsoft Academic Search

The partial domain-wall theory of exchange bias predicts bias field magnitudes and film thickness dependencies consistent with certain experimental systems. However, the theory does not account for the coercivity enhancement that accompanies the hysteresis loop shift in single domain materials. We show theoretically that the presence of an attractive domain-wall potential in the antiferromagnet, arising from magnetic impurities, for example,

Joo-Von Kim; R. L. Stamps

2005-01-01

116

Investigations of magnetic hysteresis of barium ferrite using the torsion pendulum method  

SciTech Connect

The magnetic stiffness is measured by the torsion pendulum method as a function of the applied field. Measurements are performed on random assemblies of chemically coprecipitated barium ferrite powders. The magnetic stiffness for both minor and major loops of the hysteresis cycle is measured and compared with calculated curves based on the model of coherent rotation. The discrepancies between theory and experiment are partly due to the effect of magnetic interaction.

Richter, H.J.; Hempel, K.A.

1988-11-15

117

Dynamic Hysteresis in Compacted Magnetic Nanoparticles  

NASA Astrophysics Data System (ADS)

The frequency and temperature dependent magnetic response of a bulk soft magnetic nanocomposite made by compacting Fe10Co 90 nanoparticles was measured and modeled. Electron microscopy and x-ray diffraction were used to characterize the size, composition, and structure of the nanoparticles and nanocomposite. Polyol synthesis was used to produce 200 nm particles with average grain size 20 nm and large superparamagnetic fraction. The nanoparticles were consolidated to 90% theoretical density by plasma pressure compaction. The compacted nanoparticles retained the 20 nm average grain size and large superparamagnetic fraction. The nanocomposite resistivity was more than three times that of the bulk alloy. Vibrating sample and SQUID-MPMS magnetometers were used for low frequency magnetic measurements of the nanoparticles and nanocomposite. Compaction reduced the coercivity from 175 Oe to 8 Oe and the effective anisotropy from 124 x 10 3 ergs/cc to 7.9 x 103 ergs/cc. These reductions were caused by increased exchange coupling between surface nanograins, consistent with predictions from the Random Anisotropy model. Varying degrees of exchange coupling existed within the nanocomposite, contributing to a distribution of energy barriers. A permeameter was used for frequency dependent magnetic measurements on a toroid cut from the nanocomposite. Complex permeability, coercivity, and power loss were extracted from dynamic minor hysteresis loops measured over a range of temperatures (77 K - 873 K) and frequencies (0.1 kHz - 100 kHz). The real and imaginary parts of the complex permeability spectrum showed asymmetries consistent with a distribution of energy barriers and high damping. When the complex permeability, power loss, and coercivity were scaled relative to the peak frequency of the imaginary permeability, all fell on universal curves. Various microscopic and macroscopic models for the complex permeability were investigated. The complex permeability was successfully fit by modifying the Cole-Davidson model with a scaling factor that extended the model to higher damping. The additional damping was consistent with the damping from eddy current modeling, showing that the nanocomposite's complex permeability could be explained by combining microscopic effects (the distribution of energy barriers represented by the Cole-Davidson model) with macroscopic effects (damping due to eddy currents).

Chowdary, Krishna M.

118

Hysteresis and creep in powdersHysteresis and creep in powders and grainsand grains  

E-print Network

Hysteresis and creep in powdersHysteresis and creep in powders and grainsand grains Ciprian David. Model usedDiscrete element methods. Model used Micromechanical investigation of granular soilsMicromechanical investigation of granular soils under cyclic loadingunder cyclic loading ConclusionsConclusions #12;Motivation

Harting, Jens

119

Modeling mixed clockwise and counter-clockwise hysteresis in multi-layer materials by using a generalized Jiles-Atherton model  

NASA Astrophysics Data System (ADS)

A generalized Jiles-Atherton model is proposed to describe mixed clockwise and counter-clockwise hysteresis loops. While it is physically inconsistent for homogeneous magnetic materials, this mixed type of hysteresis is exhibited by several multi-layer and superlattice materials with antiferromagnetic coupling. The modeling approach is based on a newly developed clockwise hysteretic model using the Jiles-Atherton framework and its linear superposition to the classical counter-clockwise version. The resulting technique is implemented in open-access academic software for hysteresis and simulation samples are presented in the paper.

Andrei, Petru; Mehta, Mohit; Dimian, Mihai

2014-02-01

120

Analysis of a hysteresis motor with overexcitation  

SciTech Connect

The performance of a hysteresis motor can be improved greatly if it is overexcited for a short period when running at synchronous speed. The change in the magnetic state of the rotor hysteresis material, when the stator voltage is raised and then reduced to the original value, is described in detail. Based on this, a method for the calculation of the motor performance after overexcitation is proposed, and the effect of overexcitation on the motor performance is clarified by using this method. Good agreement is found between the calculated and the measured results.

Kataoka, T.; Ishikawa, T.; Takahasi, T.

1982-11-01

121

Tracking Control of Shape-Memory-Alloy Actuators Based on Self-Sensing Feedback and Inverse Hysteresis Compensation  

PubMed Central

Shape memory alloys (SMAs) offer a high power-to-weight ratio, large recovery strain, and low driving voltages, and have thus attracted considerable research attention. The difficulty of controlling SMA actuators arises from their highly nonlinear hysteresis and temperature dependence. This paper describes a combination of self-sensing and model-based control, where the model includes both the major and minor hysteresis loops as well as the thermodynamics effects. The self-sensing algorithm uses only the power width modulation (PWM) signal and requires no heavy equipment. The method can achieve high-accuracy servo control and is especially suitable for miniaturized applications. PMID:22315530

Liu, Shu-Hung; Huang, Tse-Shih; Yen, Jia-Yush

2010-01-01

122

Thermal hysteresis and friction of phase boundary motion in ferromagnetic Ni52Mn23Ga25 single crystals  

NASA Astrophysics Data System (ADS)

We calculated the energy consumed for phase boundary motion in a Ni52Mn23Ga25 single-crystalline sample during martensitic transformation using a boundary friction phenomenological theory. It was found that the energy consumed for phase boundary motion is 13.14 J/mol, only a small part of the latent heat of martensitic transformation. Furthermore, the results of transformation loops measured by ac magnetic susceptibility proved that the thermal hysteresis of martensitic transformation is in direct proportion to the volume fraction of martensite. It was also indicated that the thermal hysteresis of martensitic transformation originates from the friction of phase boundary motion.

Wang, Wen-Hong; Chen, Jing-Lang; Liu, Zhu-Hong; Wu, Guang-Heng; Zhan, Wen-Shan

2002-01-01

123

A Jiles-Atherton and fixed-point combined technique for time periodic magnetic field problems with hysteresis  

SciTech Connect

The hysteresis phenomenon can significantly affect the behavior of magnetic cores in electrical machines and devices. This paper presents a finite element solution of periodic steady state magnetic field problems in soft materials with scalar hysteresis. The Jiles-Atherton model is employed for the generation of symmetric B-H loops and it is coupled with the Fixed Point Technique for handling magnetic nonlinearities. The proposed procedure is applied to a hysteretic model problem whose analytical solution is available. The results show that the Fixed Point Technique can efficiently deal with non-single valued material characteristics under periodic operating conditions.

Chiampi, M.; Repetto, M. [Politecnico di Torino (Italy). Dipt. di Ingegneria Elettrica Industriale] [Politecnico di Torino (Italy). Dipt. di Ingegneria Elettrica Industriale; Chiarabaglio, D. [Istituto Elettrotecnico Nazionale Galileo Ferraris, Torino (Italy)] [Istituto Elettrotecnico Nazionale Galileo Ferraris, Torino (Italy)

1995-11-01

124

Flexible pivot mount eliminates friction and hysteresis  

NASA Technical Reports Server (NTRS)

Flexible steel pivot mount, suspended by flat vertical beryllium copper springs, is capable of rotation, free of hysteresis and starting friction. Mount requires no lubrication, is made in varying sizes, and is driven with either dc torque motor or mechanical linkage.

Highman, C. O.

1970-01-01

125

Circuit increases capability of hysteresis synchronous motor  

NASA Technical Reports Server (NTRS)

Frequency and phase detector circuit enables a hysteresis synchronous motor to drive a load of given torque value at a precise speed determined by a stable reference. This technique permits driving larger torque loads with smaller motors and lower power drain.

Markowitz, I. N.

1967-01-01

126

Macroscopic theory for capillary-pressure hysteresis.  

PubMed

In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials. PMID:25646688

Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry

2015-03-01

127

Managing Hysteresis: Three Cornerstones to Fiscal Stability  

ERIC Educational Resources Information Center

The effects of the Great Recession of 2007-2009 continue to challenge school business officials (SBOs) and other education leaders as they strive to prepare students for the global workforce. Economists have borrowed a word from chemistry to describe this state of affairs: hysteresis--the lingering effects of the past on the present. Today's SBOs…

Weeks, Richard

2012-01-01

128

Hysteresis compensation in PZT bimorph mirrors: Preisach's classical and non-linear models  

NASA Astrophysics Data System (ADS)

A number of reflective wavefront correctors used in adaptive optics are based on the use of piezoelectric effect, either in piston, tip/tilt or curvature devices. The relation between the voltage applied to drive these devices and the mechanical response always presents hysteresis to some extent. In this work we study the performance of Preisach's classical and non-linear models of hysteresis on a bimorph mirror, which is a curvature device, but both models can also be applied to piston and tip/tilt devices. Bimorph mirrors with PZT actuators and a passive glass substrate were tested in an adaptive optics test-bed (AOTB) using a Shack-Hartmann wavefront sensor. First- and second-order reversal curves were sampled uniformly in Preisach space, and interpolation algorithms were implemented to test Preisach's classical and non-linear forward models respectively. Then, arbitrary voltage configuration sequences were applied to the mirror and the responses were recorded. Finally, the inversion of the models was implemented and included in the AOTB linear control algorithm to test the closed-loop performance. We found that both hysteresis models provide a similar improvement in the open-loop error. The improvement estimation depends on the particular sequence applied, the number of samples of the Preisach function and noise among other factors. Finally, we present data showing that the hysteretic behavior in a multi-electrode mirror is, within experimental error, independent of the electrode geometry, area and location.

Dubra, Alfredo; Massa, John S.; Paterson, Carl

2005-12-01

129

Significance of conservative asparagine residues in the thermal hysteresis activity of carrot antifreeze protein.  

PubMed Central

The approximately 24-amino-acid leucine-rich tandem repeat motif (PXXXXXLXXLXXLXLSXNXLXGXI) of carrot antifreeze protein comprises most of the processed protein and should contribute at least partly to the ice-binding site. Structural predictions using publicly available online sources indicated that the theoretical three-dimensional model of this plant protein includes a 10-loop beta-helix containing the approximately 24-amino-acid tandem repeat. This theoretical model indicated that conservative asparagine residues create putative ice-binding sites with surface complementarity to the 1010 prism plane of ice. We used site-specific mutagenesis to test the importance of these residues, and observed a distinct loss of thermal hysteresis activity when conservative asparagines were replaced with valine or glutamine, whereas a large increase in thermal hysteresis was observed when phenylalanine or threonine residues were replaced with asparagine, putatively resulting in the formation of an ice-binding site. These results confirmed that the ice-binding site of carrot antifreeze protein consists of conservative asparagine residues in each beta-loop. We also found that its thermal hysteresis activity is directly correlated with the length of its asparagine-rich binding site, and hence with the size of its ice-binding face. PMID:14531728

Zhang, Dang-Quan; Liu, Bing; Feng, Dong-Ru; He, Yan-Ming; Wang, Shu-Qi; Wang, Hong-Bin; Wang, Jin-Fa

2004-01-01

130

Hysteresis heating based induction bonding of thermoplastic composites  

Microsoft Academic Search

The bonding of polymer matrix composites using magnetic particulate susceptor materials for hysteresis induction heating is investigated in this study. Hysteresis heating is tailored through careful design of the microstructure of magnetic particulate polymer films. The bond strength of hysteresis-welded materials is comparable to that of autoclave-welded materials while offering an order of magnitude reduction in cycle time. The relative

W. Suwanwatana; S. Yarlagadda; J GILLESPIEJR

2006-01-01

131

Quantum Hydrodynamic Simulation of Hysteresis in the Resonant Tunneling Diode  

Microsoft Academic Search

Hysteresis in the current-voltage curve of a resonant tunneling diode is simulated and analyzed in the quantum hydrodynamic (QHD) model for semiconductor devices. The simulations are the first to show hysteresis in the QHD equations and to confirm that bistability is an intrinsic property of the resonant tunneling diode. Hysteresis appears in many settings in fluid dynamics. The simulations presented

Zhangxin Chen; Bernardo Cockburn; Carl L. Gardner; Joseph W. Jerome

1995-01-01

132

Case study of Chilled Water Loop Low Delta-T Fault Diagnosis  

E-print Network

Case study of Chilled Water Loop Low ?T Fault Diagnosis Lei Wang1, Ph.D., P.E. Ken Meline2, P.E. James Watt1, P.E. Bahman Yazdani1 P.E., David E. Claridge1, Ph.D., P.E 1Energy Systems Laboratory, Texas A&M Engineering Experiment Station... Case Study of Chilled Water Loop Low DT Fault Diagnosis Presented by Lei Wang Ph.D. P.E. Energy Systems Laboratory, Texas A&M University System Sep. 15, 2014 Energy Systems Laboratory p. 1 ESL-IC-14-09-12a Proceedings of the 14th International...

Wang, L.; Meline, K.; Watt, J.

2014-01-01

133

The stress dependence of magnetostriction hysteresis in TbDyFe [110] oriented crystal  

NASA Astrophysics Data System (ADS)

The magnetostriction curves and minor loops of the TbDyFe [110] oriented crystal are tested under different compressive pre-stress from 0 to 120 MPa. It is observed that the magnetostriction hysteresis first increases from about 33 Oe under 0 MPa, achieves the maximum of about 70 Oe under 30 MPa, and then decreases to about 16 Oe under 120 MPa (near disappearance) with an increase in the compressive pre-stress. By the theoretical simulation, it is found that upon increasing the compressive pre-stress the dominant energy changes from magnetocrystalline anisotropy energy to magnetoelastic energy. This leads to the domain rotation mode changing from irreversibility to reversibility and consequently results in the decrease of magnetostriction hysteresis, which explains the experimental results very well.

Wang, Zhibin; Liu, Jinghua; Jiang, Chengbao; Xu, Huibin

2011-06-01

134

A guided enquiry approach to introduce basic concepts concerning magnetic hysteresis to minimize student misconceptions  

NASA Astrophysics Data System (ADS)

Basic concepts concerning magnetic hysteresis are of vital importance in understanding magnetic materials. However, these concepts are often misinterpreted by many students and even textbooks. We summarize the most common misconceptions and present a new approach to help clarify these misconceptions and enhance students’ understanding of the hysteresis loop. In this approach, students are required to perform an experiment and plot the measured magnetization values and thereby calculated demagnetizing field, internal field, and magnetic induction as functions of the applied field point by point on the same graph. The concepts of the various coercivity, remanence, saturation magnetization, and saturation induction will not be introduced until this stage. By plotting this graph, students are able to interlink all the preceding concepts and intuitively visualize the underlying physical relations between them.

Wei, Yajun; Zhai, Zhaohui; Gunnarsson, Klas; Svedlindh, Peter

2014-11-01

135

Hysteresis phenomenon and multistability in figure-of-eight microstructured fiber laser  

NASA Astrophysics Data System (ADS)

We report a theoretical investigation of multi-pulse emission of a microstructured figure-of-eight fiber laser operating in passive mode-locking. The proposed laser is mode locked by the nonlinear amplifying loop mirror (NALM). We study, in this paper, the hysteresis dependence and the number of pulses in steady state as a function of both the small signal gain and the nonlinear coefficient of microstructured fiber. The numerical simulation confirms that the pulse splitting is a consequence of the energy quantization in anomalous dispersion. Moreover, our results suggest that the hysteresis phenomenon is an intrinsic feature of the mode-locked fiber lasers independently of the exact mode-locking mechanism. Finally, we identify that the nonlinear coefficient of microstructured fiber plays a key role in the formation of multi-soliton.

Guesmi, Khmaies; Bahloul, Faouzi; Salhi, Mohamed; Sanchez, François; Attia, Rabah

2015-04-01

136

Characterizing piezoscanner hysteresis and creep using optical levers and a reference nanopositioning stage  

SciTech Connect

A method using atomic force microscope (AFM) optical levers and a reference nanopositioning stage has been developed to characterize piezoscanner hysteresis and creep. The piezoscanner is fixed on a closed-loop nanopositioning stage, both of which have the same arrangement on each axis of the three spatial directions inside the AFM-based nanomanipulation system. In order to achieve characterization, the optical lever is used as a displacement sensor to measure the relative movement between the nanopositioning stage and the piezoscanner by lateral tracking a well-defined slope with the tapping mode of the AFM cantilever. This setup can be used to estimate a piezoscanner's voltage input with a reference displacement from the nanopositioning stage. The hysteresis and creep were accurately calibrated by the method presented, which use the current setup of the AFM-based nanomanipulation system without any modification or additional devices.

Xie, H.; Regnier, S. [Institute of Intelligent System and Robotics, University of Pierre and Marie Curie/CNRS UMR 7222, 4 Place Jussieu, 75005 Paris (France); Rakotondrabe, M. [Department of Automatic Control and Micro-Mechatronic Systems, FEMTO-ST Institute, CNRS UMR 6174-UFC/ENSMM/UTBM, 24, Rue Alain Savary, 25000 Besancon (France)

2009-04-15

137

Rotational hysteresis of exchange-spring magnets.  

SciTech Connect

We highlight our experimental studies and micromagnetic simulations of the rotational hysteresis in exchange-spring magnets. Magneto-optical imaging and torque magnetometry measurements for SmCo/Fe exchange-spring films with uniaxial in-plane anisotropy show that the magnetization rotation created in the magnetically soft Fe layer by a rotating magnetic field is hysteretic. The rotational hysteresis is due to the reversal of the chirality of the spin spiral structure. Micromagnetic simulations reveal two reversal modes of the chirality, one at low fields due to an in-plane untwisting of the spiral, and the other, at high fields, due to an out-of-plane fanning of the spiral.

Jiang, J.S.; Bader, S.D.; Kaper, H.; Leaf, G.K.; Shull, R.D.; Shapiro, A.J.; Gornakov, V.S.; Nikitenko, V.I.; Platt, C.L.; Berkowitz, A.E.; David, S.; Fullerton, E.E.

2002-03-27

138

Measurement method for determining the magnetic hysteresis effects of reluctance actuators by evaluation of the force and flux variation  

NASA Astrophysics Data System (ADS)

A measurement method is presented which identifies the magnetic hysteresis effects present in the force of linear reluctance actuators. The measurement method is applied to determine the magnetic hysteresis in the force of an E-core reluctance actuator, with and without pre-biasing permanent magnet. The force measurements are conducted with a piezoelectric load cell (Kistler type 9272). This high-bandwidth force measurement instrument is identified in the frequency domain using a voice-coil actuator that has negligible magnetic hysteresis and eddy currents. Specifically, the phase delay between the current and force of the voice-coil actuator is used for the calibration of the measurement instrument. This phase delay is also obtained by evaluation of the measured force and flux variation in the E-core actuator, both with and without permanent magnet on the middle tooth. The measured magnetic flux variation is used to distinguish the phase delay due to magnetic hysteresis from the measured phase delay between the current and the force of the E-core actuator. Finally, an open loop steady-state ac model is presented that predicts the magnetic hysteresis effects in the force of the E-core actuator.

Vrijsen, N. H.; Jansen, J. W.; Compter, J. C.; Lomonova, E. A.

2013-07-01

139

Magnetoabsorption and magnetic hysteresis in Ni ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Nickel ferrite nanoparticles were prepared by a modified sol-gel technique employing coconut oil, and then annealed at different temperatures in 400-1200 °C range. This route of preparation has revealed to be one efficient and cheap technique to obtain high quality nickel ferrite nanosized powder. Sample particles sizes obtained with XRD data and Scherrer's formula lie in 13 nm to 138 nm, with increased size with annealing temperature. Hysteresis loops have been obtained at room temperature with an inductive method. Magnetic field induced microwave absorption in nanoscale ferrites is a recent an active area of research, in order to characterize and explore potential novel applications. In the present work microwave magnetoabsorption data of the annealed nickel ferrite nanoparticles are presented. These data have been obtained with a system based on a network analyzer that operates in the frequency range 0 - 8.5 GHz. At fields up to 400 mT we can observe a peak according to ferromagnetic resonance theory. Sample annealed at higher temperature exhibits different absorption, coercivity and saturation magnetization figures, revealing its multidomain character.

Hernández-Gómez, P.; Muñoz, J. M.; Valente, M. A.; Torres, C.; de Francisco, C.

2013-01-01

140

Avalanches and hysteresis in frustrated superconductors and XY spin glasses  

NASA Astrophysics Data System (ADS)

We study avalanches along the hysteresis loop of long-range interacting spin glasses with continuous XY symmetry, which serves as a toy model of granular superconductors with long-range and frustrated Josephson couplings. We identify sudden jumps in the T =0 configurations of the XY phases as an external field is increased. They are initiated by the softest mode of the inverse susceptibility matrix becoming unstable, which induces an avalanche of phase updates (or spin alignments). We analyze the statistics of these events and study the correlation between the nonlinear avalanches and the soft mode that initiates them. We find that the avalanches follow the directions of a small fraction of the softest modes of the inverse susceptibility matrix, similarly as was found in avalanches in jammed systems. In contrast to the similar Ising spin glass (Sherrington-Kirkpatrick) studied previously, we find that avalanches are not distributed with a scale-free power law but rather have a typical size which scales with the system size. We also observe that the Hessians of the spin-glass minima are not part of standard random matrix ensembles as the lowest eigenvector has a fractal support.

Sharma, Auditya; Andreanov, Alexei; Müller, Markus

2014-10-01

141

Avalanches and hysteresis in frustrated superconductors and XY spin glasses.  

PubMed

We study avalanches along the hysteresis loop of long-range interacting spin glasses with continuous XY symmetry, which serves as a toy model of granular superconductors with long-range and frustrated Josephson couplings. We identify sudden jumps in the T=0 configurations of the XY phases as an external field is increased. They are initiated by the softest mode of the inverse susceptibility matrix becoming unstable, which induces an avalanche of phase updates (or spin alignments). We analyze the statistics of these events and study the correlation between the nonlinear avalanches and the soft mode that initiates them. We find that the avalanches follow the directions of a small fraction of the softest modes of the inverse susceptibility matrix, similarly as was found in avalanches in jammed systems. In contrast to the similar Ising spin glass (Sherrington-Kirkpatrick) studied previously, we find that avalanches are not distributed with a scale-free power law but rather have a typical size which scales with the system size. We also observe that the Hessians of the spin-glass minima are not part of standard random matrix ensembles as the lowest eigenvector has a fractal support. PMID:25375434

Sharma, Auditya; Andreanov, Alexei; Müller, Markus

2014-10-01

142

Development of a real-time closed-loop micro-\\/nano-positioning system embedded with a capacitive sensor  

Microsoft Academic Search

The hysteresis and nonlinearity of the PZT is an actual problem in the piezo-driven micro-\\/nano-positioning stage, especially for the open-loop positioning stage. The study presents the development of an NI cRIO9074-based real-time closed-loop micro-\\/nano-positioning system, to overcome the problem of the hysteresis and nonlinearity of a PZT and to increase the positioning speed of the positioning stage. The developed system

Fang-Jung Shiou; Chao-Jung Chen; Chia-Jui Chiang; Ke-Jhen Liou; Shu-Chung Liao; Huay-Chung Liou

2010-01-01

143

Scalar and vector hysteresis simulations using HysterSoft  

NASA Astrophysics Data System (ADS)

Hysteresis modeling has become an important research area with many applications in science and engineering. In this article we present a unified and robust simulation framework designed to perform scalar and vector hysteresis modeling. The framework is based on HysterSoft© which is a simulation platform that can be interfaced with other libraries and simulation programs to model various aspects of hysteresis. We describe the main features of our simulation framework by focusing on scalar and vector hysteresis modeling, direct and inverse modeling, dynamic hysteresis modeling, first-order reversal-curves analysis, identification of the scalar and vector Preisach distribution function using an experimental first- order reversal-curves, noise passage analysis through hysteretic systems, and thermal relaxation in scalar and vector hysteresis. The simulation modules, the user-defined features, and various parameter identification techniques are also presented.

Dimian, M.; Andrei, P.

2015-02-01

144

Nonlinear space charge dynamics in mixed ionic-electronic conductors: Resistive switching and ferroelectric-like hysteresis of electromechanical response  

NASA Astrophysics Data System (ADS)

We performed self-consistent modelling of nonlinear electrotransport and electromechanical response of thin films of mixed ionic-electronic conductors (MIEC) allowing for steric effects of mobile charged defects (ions, protons, or vacancies), electron degeneration, and Vegard stresses. We establish correlations between the features of the nonlinear space-charge dynamics, current-voltage, and bending-voltage curves for different types of the film electrodes. A pronounced ferroelectric-like hysteresis of the bending-voltage loops and current maxima on the double hysteresis current-voltage loops appear for the electron-transport electrodes. The double hysteresis loop with pronounced humps indicates a memristor-type resistive switching. The switching occurs due to the strong nonlinear coupling between the electronic and ionic subsystems. A sharp meta-stable maximum of the electron density appears near one open electrode and moves to another one during the periodic change of applied voltage. Our results can explain the nonlinear nature and correlation of electrical and mechanical memory effects in thin MIEC films. The analytical expression proving that the electrically induced bending of MIEC films can be detected by interferometric methods is derived.

Morozovska, Anna N.; Eliseev, Eugene A.; Varenyk, Olexandr V.; Kim, Yunseok; Strelcov, Evgheni; Tselev, Alexander; Morozovsky, Nicholas V.; Kalinin, Sergei V.

2014-08-01

145

Nonlinear space charge dynamics in mixed ionic-electronic conductors: Resistive switching and ferroelectric-like hysteresis of electromechanical response  

SciTech Connect

We performed self-consistent modelling of nonlinear electrotransport and electromechanical response of thin films of mixed ionic-electronic conductors (MIEC) allowing for steric effects of mobile charged defects (ions, protons, or vacancies), electron degeneration, and Vegard stresses. We establish correlations between the features of the nonlinear space-charge dynamics, current-voltage, and bending-voltage curves for different types of the film electrodes. A pronounced ferroelectric-like hysteresis of the bending-voltage loops and current maxima on the double hysteresis current-voltage loops appear for the electron-transport electrodes. The double hysteresis loop with pronounced humps indicates a memristor-type resistive switching. The switching occurs due to the strong nonlinear coupling between the electronic and ionic subsystems. A sharp meta-stable maximum of the electron density appears near one open electrode and moves to another one during the periodic change of applied voltage. Our results can explain the nonlinear nature and correlation of electrical and mechanical memory effects in thin MIEC films. The analytical expression proving that the electrically induced bending of MIEC films can be detected by interferometric methods is derived.

Morozovska, Anna N.; Morozovsky, Nicholas V. [Institute of Physics NAS of Ukraine, 46, pr. Nauki, Kyiv 03028 (Ukraine); Eliseev, Eugene A. [Institute of Problems for Material Sciences, NAS of Ukraine, 3, Krjijanovskogo str., Kyiv 03028 Ukraine (Ukraine); Varenyk, Olexandr V. [Taras Shevchenko Kyiv National University, Radiophysical Faculty 4, pr. Akademika Hlushkova, 03022 Kyiv (Ukraine); Kim, Yunseok [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Strelcov, Evgheni; Tselev, Alexander; Kalinin, Sergei V. [The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2014-08-14

146

Dipole-dipole interaction and its concentration dependence of magnetic fluid evaluated by alternating current hysteresis measurement  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles (MNPs) are used as therapeutic and diagnostic tools, such as for treating hyperthermia and in magnetic particle imaging, respectively. Magnetic relaxation is one of the heating mechanisms of MNPs. Brownian and Néel relaxation times are calculated conventional theories; however, the influence of dipole-dipole interactions has not been considered in conventional models. In this study, water-dispersed MNPs of different concentrations and MNPs fixed with an epoxy bond were prepared. dc and ac hysteresis loops for each sample were measured. With respect to both dc and ac hysteresis loops, magnetization decreased with the increase in MNP concentration because of inhibition of magnetic moment rotation due to dipole-dipole interactions. Moreover, intrinsic loss power (ILP) was estimated from the areas of the ac hysteresis loops. The dependence of ILP on the frequency of the magnetic field was evaluated for each MNP concentration. The peak frequency of ILP increased with the decrease in MNP concentration. These peaks were due to Brownian relaxation, as they were not seen with the fixed sample. This indicates that the Brownian relaxation time became shorter with lower MNP concentration, because the weaker dipole-dipole interactions with lower concentrations suggested that the magnetic moments could rotate more freely.

Ota, Satoshi; Yamada, Tsutomu; Takemura, Yasushi

2015-05-01

147

Stage-Discharge Hysteresis and Bedforms (Invited)  

NASA Astrophysics Data System (ADS)

One of the most commonly-cited (and earliest recorded) examples of hysteresis in geomorphology and hydraulics is that arising in river stage-discharge rating curves, where different stages occur on the rising and falling limbs of a hydrograph for the same discharge. This is typically attributed to bedform dynamics, particularly in the case where bedforms disappear during increasing flows due to high Froude numbers and/or suspended load and are subsequently reformed on the falling limb of the hydrograph. In that case, the effective form drag of the bedforms is significantly different for the same discharge, as the bedforms have very different shapes on the rising and falling limb. Although the effect is most noticeable in the case where bedforms 'wash out', it is important to realize that the same effects give rise to weaker forms of hysteresis even when bedforms are uniformly present but evolve in response to changing flows. In this presentation, examples of both strong and weak hysteresis are shown using results from two- and three-dimensional mobile bed models which directly resolve the pressure distribution on the bed (and hence the form drag on bed features). Computations are compared to laboratory measurements of bedform behavior to support the use of such computations for predicting bedform behavior in rapidly varying flows. To connect this to more practical computations for larger-scale rivers, we describe a straightforward method for combining bedform dynamics calculations with much coarser planform river models in order to include the effect of bedform shape changes on effective bed roughness. Results from this method are shown for the Kootenai River in Northern Idaho. These results support the use of this hybrid technique when models capable of resolving bedform mechanics are impractical.

Nelson, J. M.; Giri, S.; Shimizu, Y.; Nabi, M.; McDonald, R.

2013-12-01

148

Hysteresis prediction inside magnetic shields and application.  

PubMed

We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60??T. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission. PMID:25085183

Mori?, Igor; De Graeve, Charles-Marie; Grosjean, Olivier; Laurent, Philippe

2014-07-01

149

Hysteresis prediction inside magnetic shields and application  

SciTech Connect

We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60??T. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission.

Mori?, Igor [Observatoire de Paris, SYRTE, Avenue Denfert 77, 75014 Paris (France); CNES, Edouard Belin 18, 31400 Toulouse (France); De Graeve, Charles-Marie [SOGETI High Tech, chemin Laporte 3, 31300 Toulouse (France); Grosjean, Olivier [CNES, Edouard Belin 18, 31400 Toulouse (France); Laurent, Philippe [Observatoire de Paris, SYRTE, Avenue Denfert 77, 75014 Paris (France)

2014-07-15

150

Hysteresis prediction inside magnetic shields and application  

NASA Astrophysics Data System (ADS)

We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60 ?T. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission.

Mori?, Igor; De Graeve, Charles-Marie; Grosjean, Olivier; Laurent, Philippe

2014-07-01

151

Application of magnetomechanical hysteresis modeling to magnetic techniques for monitoring neutron embrittlement and biaxial stress  

SciTech Connect

The objective is to investigate experimentally and theoretically the effects of neutron embrittlement and biaxial stress on magnetic properties in steels, using various magnetic measurement techniques. Interaction between experiment and modeling should suggest efficient magnetic measurement procedures for determining neutron embrittlement biaxial stress. This should ultimately assist in safety monitoring of nuclear power plants and of gas and oil pipelines. In the first six months of this first year study, magnetic measurements were made on steel surveillance specimens from the Indian Point 2 and D.C. Cook 2 reactors. The specimens previously had been characterized by Charpy tests after specified neutron fluences. Measurements now included: (1) hysteresis loop measurement of coercive force, permeability and remanence, (2) Barkhausen noise amplitude; and (3) higher order nonlinear harmonic analysis of a 1 Hz magnetic excitation. Very good correlation of magnetic parameters with fluence and embrittlement was found for specimens from the Indian Point 2 reactor. The D.C. Cook 2 specimens, however showed poor correlation. Possible contributing factors to this are: (1) metallurgical differences between D.C. Cook 2 and Indian Point 2 specimens; (2) statistical variations in embrittlement parameters for individual samples away from the stated men values; and (3) conversion of the D.C. Cook 2 reactor to a low leakage core configuration in the middle of the period of surveillance. Modeling using a magnetomechanical hysteresis model has begun. The modeling will first focus on why Barkhausen noise and nonlinear harmonic amplitudes appear to be better indicators of embrittlement than the hysteresis loop parameters.

Sablik, M.J.; Kwun, H.; Rollwitz, W.L.; Cadena, D.

1992-01-01

152

Unemployment hysteresis and the NAIRU: a ratchet model  

Microsoft Academic Search

In the 1970s and 1980s the USA and European economies experienced unemployment rates that persistently drifted upwards. The present paper captures this phenomenon by a simple extension of the hysteresis approach to the natural rate hypothesis of unemployment using a ratchet model. The impact of peak unemployment levels on unemployment hysteresis is incorporated using a traditional ratchet model. The model

David J. Smyth; Joshy Z. Easaw

2001-01-01

153

Low-Voltage CMOS Comparators With Programmable Hysteresis  

E-print Network

............................................................28 3.2.2 High-swing cascode current source.....................................29 3.2.3 OperationLow-Voltage CMOS Comparators With Programmable Hysteresis BY VISHNU B. KULKARNI Master of Science of comparators with programmable hysteresis. Optimizations are done in order to obtain minimum DC offsets

Furth, Paul

154

A Domain Wall Model for Hysteresis in Piezoelectric Materials  

E-print Network

A Domain Wall Model for Hysteresis in Piezoelectric Materials Ralph C. Smith Center for Research constitutive relations in piezoelec­ tric materials at moderate to high drive levels. Hysteresis and nonlinearities are due to the domain structure inherent to the materials and both aspects must be addressed

155

The influence of temperature hysteresis at metal-semiconductor phase transition on current-voltage characteristic of VO 2 –based ceramics  

Microsoft Academic Search

The current-voltage characteristics of ceramics (wt%) 80VO2-15VPG-5Cu and 45VO2-15VPG-5Cu-35SnO2 were investigated (VPG—vanadium phosphate glass). After switching to high electric current, these characteristics show a hysteresis loop in the electric current increase-decrease cycle. The cause of hysteresis is the different phase transition temperatures in VO2 crystallites for transition from semiconductor phase to metallic phase and for the reverse transition. The distinction

A. I. Ivon; V. R. Kolbunov; I. M. Chernenko

2005-01-01

156

DNA looping.  

PubMed Central

DNA-looping mechanisms are part of networks that regulate all aspects of DNA metabolism, including transcription, replication, and recombination. DNA looping is involved in regulation of transcriptional initiation in prokaryotic operons, including ara, gal, lac, and deo, and in phage systems. Similarly, in eukaryotic organisms, the effects of enhancers appear to be mediated at least in part by loop formation, and examples of DNA looping by hormone receptor proteins and developmental regulatory proteins have been found. In addition, instances of looped structures have been found in replication and in recombination in both prokaryotes and eukaryotes. DNA loop formation may have different functions in different cellular contexts; in some cases, the loop itself is requisite for regulation, while in others the increase in the effective local concentration of protein may account for the effects observed. The ability of DNA to form loops is affected by the distance between binding sites; by the DNA sequence, which determines deformability and bendability; and by the presence of other proteins that exert an influence on the conformation of a particular sequence. Alteration of the stability of DNA loops and/or protein-DNA binding by extra- or intracellular signals provides responsivity to changing metabolic or environmental conditions. The fundamental property of site-specific protein binding to DNA can be combined with protein-protein and protein-ligand interaction to generate a broad range of physiological states. PMID:1579106

Matthews, K S

1992-01-01

157

Positive hysteresis of Ce-doped GAGG scintillator  

NASA Astrophysics Data System (ADS)

Positive hysteresis and radiation tolerance to high-dose radiation exposure were investigated for Ce 1% and 3% doped Gd3(Al, Ga)5O12 (Ce:GAGG) crystal scintillator on comparison with other garnet scintillators such Ce:YAG, Ce:LuAG, Pr:LuAG, and ceramic Ce:GAGG. When they were irradiated by several Gy 60Co ?-rays, Ce 1% doped GAGG crystal exhibited ?20% light yield enhancement (positive hysteresis). This is the first time to observe positive hysteresis in Ce doped GAGG. On the other hand, other garnet materials did not show the positive hysteresis and their light yields were stable after 800 Gy irradiation except Pr:LuAG. The light yield of Pr:LuAG decreased largely. When irradiated Ce:GAGG which showed positive hysteresis was evaluated in Synchrotron facility (UVSOR), new excitation band was created around 60 nm.

Yanagida, Takayuki; Fujimoto, Yutaka; Koshimizu, Masanori; Watanabe, Kenichi; Sato, Hiroki; Yagi, Hideki; Yanagitani, Takagimi

2014-10-01

158

Hysteresis behavior during reactive magnetron sputtering of Al{sub 2}O{sub 3} using a rotating cylindrical magnetron  

SciTech Connect

Rotating cylindrical magnetrons are used intensively on industrial scale. A rotating cylindrical magnetron on laboratory scale makes it possible to study this deposition technique in detail and under well controlled conditions. Therefore, a small scale rotating cylindrical magnetron was designed and used to study the influence of the rotation speed on the hysteresis behavior during reactive magnetron sputtering of aluminum in Ar/O{sub 2} in dc mode. This study reveals that the hysteresis shifts towards lower oxygen flows when the rotation speed of the target is increased, i.e., target poisoning occurs more readily when the rotation speed is increased. The shift is more pronounced for the lower branch of the hysteresis loop than for the upper branch of the hysteresis. This behavior can be understood qualitatively. The results also show that the oxidation mechanism inside the race track is different from the oxidation mechanism outside the race track. Indeed, outside the race track the oxidation mechanism is only defined by chemisorption while inside the race track reactive ion implantation will also influence the oxidation mechanism.

Depla, D.; Haemers, J.; Buyle, G.; Gryse, R. de [Department of Solid State Sciences, Ghent University, Krijgslaan 281 (S1), B-9000 Ghent (Belgium)

2006-07-15

159

Thermal hysteresis behaviors of thermoelectric properties  

NASA Astrophysics Data System (ADS)

Thermoelectric behaviors for the thermal cycles between room and high temperatures are investigated in (Bi,Sb)2Te3 and Bi2S3. Because the reliability and reproducibility of the data against repeated heating are required, the Harman method is adopted to evaluate the figure of merit, ZT, in which only electrical contacts are needed. The electrical contacts are made by the spot welding method using a simple and low-power machine made in our laboratory to avoid damage to the samples. Thermoelectric properties are changed by repeating thermal cycles, though their rate of change is not always very high and is material dependent. The carrier number dominantly contributes to the thermal hysteresis of the thermoelectric properties upon the repetition of the thermal cycles, which actually affects the sample as an annealing effect. It is pointed out that changes in thermoelectric properties upon the repetition of the thermal cycles should be examined beforehand in practical applications.

Iwasaki, Hideo

2014-12-01

160

A Hysteresis Model for Piezoceramic Materials  

NASA Technical Reports Server (NTRS)

This paper addresses the modeling of nonlinear constitutive relations and hysteresis inherent to piezoceramic materials at moderate to high drive levels. Such models are, necessary to realize the, full potential of the materials in high performance control applications, and a necessary prerequisite is the development of techniques which permit control implementation. The approach employed here is based on the qualification of reversible and irreversible domain wall motion in response to applied electric fields. A comparison with experimental data illustrates that because the resulting ODE model is physics-based, it can be employed for both characterization and prediction of polarization levels throughout the range of actuator operation. Finally, the ODE formulation is amenable to inversion which facilitates the development of an inverse compensator for linear control design.

Smith, Ralph C.; Ounaies, Zoubeida

1999-01-01

161

Contact Angle Hysteresis on Superhydrophobic Stripes  

E-print Network

We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, $\\phi_S$. It is shown that the receding regime is determined by a longitudinal sliding motion the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e. is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with $\\phi_S$, in contrast to predictions of the Cassie equation. To interpret this we develop a simple theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the elastic energy of strong defects at the borders of stripes, which scales as $\\phi_S^2 \\ln \\phi_S$. The advancing contact angle was found to be anisotropic, except as in a dilute regime, and its value is determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on $\\phi_S$, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at $\\phi_S\\simeq 0.5$. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be proportional to $\\phi_S^2$. Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when $\\phi_S\\leq 0.2$.

Alexander L. Dubov; Ahmed Mourran; Martin Möller; Olga I. Vinogradova

2014-07-21

162

Hysteresis in Pressure-Driven DNA Denaturation  

PubMed Central

In the past, a great deal of attention has been drawn to thermal driven denaturation processes. In recent years, however, the discovery of stress-induced denaturation, observed at the one-molecule level, has revealed new insights into the complex phenomena involved in the thermo-mechanics of DNA function. Understanding the effect of local pressure variations in DNA stability is thus an appealing topic. Such processes as cellular stress, dehydration, and changes in the ionic strength of the medium could explain local pressure changes that will affect the molecular mechanics of DNA and hence its stability. In this work, a theory that accounts for hysteresis in pressure-driven DNA denaturation is proposed. We here combine an irreversible thermodynamic approach with an equation of state based on the Poisson-Boltzmann cell model. The latter one provides a good description of the osmotic pressure over a wide range of DNA concentrations. The resulting theoretical framework predicts, in general, the process of denaturation and, in particular, hysteresis curves for a DNA sequence in terms of system parameters such as salt concentration, density of DNA molecules and temperature in addition to structural and configurational states of DNA. Furthermore, this formalism can be naturally extended to more complex situations, for example, in cases where the host medium is made up of asymmetric salts or in the description of the (helical-like) charge distribution along the DNA molecule. Moreover, since this study incorporates the effect of pressure through a thermodynamic analysis, much of what is known from temperature-driven experiments will shed light on the pressure-induced melting issue. PMID:22496765

Hernández-Lemus, Enrique; Nicasio-Collazo, Luz Adriana; Castañeda-Priego, Ramón

2012-01-01

163

Properties of ferromagnetic film hysteresis, on the surface of a hard-magnetic antiferromagnet, with a domain structure  

NASA Astrophysics Data System (ADS)

This is a theoretical investigation of the exchange bias phenomenon, and the properties of a thin magnetic film's magnetization hysteresis loop, on the rough surface of a hard-magnetic antiferromagnet. An interface model with a periodic structure of atomic steps is presented. These atomic steps are associated with a spatially inhomogeneous distribution of the ferromagnetic film magnetization, akin to a system of domain walls. This structure leads to a complicated external field dependence of magnetization: the hysteresis curve can assume an asymmetrical shape and "fall apart" into two hysteresis loops, divided by a "horizontal plateau," or an area with constant field-independent magnetization. Such field dependence behavior has been recently observed experimentally in different ferro/antiferromagnet systems. The field dependence of magnetization has been obtained analytically using the long-wave approximation for various characteristics of ferromagnetic film (its thickness, values of exchange interaction, and magnetic anisotropy), and the interface (the period of the inhomogeneous structure, and exchange interaction through the interface). The analytical results are confirmed by numerical calculations for the corresponding discrete model with a more complex interface structure.

Kovalev, A. S.; Pankratova, M. L.

2014-11-01

164

nature neuroscience VOLUME 14 | NUMBER 9 | SEPTEMBER 2011 1105 p e r s p e c t i v e  

E-print Network

nature neuroscience VOLUME 14 | NUMBER 9 | SEPTEMBER 2011 1105 p e r s p e c t i v e In theory reviewed 513 behavioral, systems and cognitive neuroscience articles in five top-ranking journals (Science, Nature, Nature Neuroscience, Neuron and The Journal of Neuroscience) and found that 78 used the correct

Nieuwenhuis, Sander

165

Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magnetic shape memory effect  

NASA Astrophysics Data System (ADS)

Enhanced magnetic hysteresis due to boron doping in combination with magnetic shape memory effect in Ni-Mn-Ga single crystal results in new interesting functionality of magnetic shape memory (MSM) alloys such as mechanical demagnetization. In Ni50.0Mn28.5Ga21.5 single crystal, the boron doping increased magnetic coercivity from few Oe to 270 Oe while not affecting the transformation behavior and 10 M martensite structure. However, the magnetic field needed for MSM effect also increased in doped sample. The magnetic behavior is compared to undoped single crystal of similar composition. The evidence from the X-ray diffraction, magnetic domain structure, magnetization loops, and temperature evolution of the magnetic coercivity points out that the enhanced hysteresis is caused by stress-induced anisotropy.

Heczko, O.; Drahokoupil, J.; Straka, L.

2015-05-01

166

HYSTERESIS OF BACKFLOW IMPRINTED IN COLLIMATED JETS  

SciTech Connect

We report two different types of backflow from jets by performing two-dimensional special relativistic hydrodynamical simulations. One is anti-parallel and quasi-straight to the main jet (quasi-straight backflow), and the other is a bent path of the backflow (bent backflow). We find that the former appears when the head advance speed is comparable to or higher than the local sound speed at the hotspot, while the latter appears when the head advance speed is slower than the sound speed at the hotspot. Bent backflow collides with the unshocked jet and laterally squeezes the jet. At the same time, a pair of new oblique shocks is formed at the tip of the jet and new bent fast backflows are generated via these oblique shocks. The hysteresis of backflow collisions is thus imprinted in the jet as a node and anti-node structure. This process also promotes broadening of the jet cross-sectional area and also causes a decrease in the head advance velocity. This hydrodynamic process may be tested by observations of compact young jets.

Mizuta, Akira [Center for Frontier Science, Chiba University Yayoi-cho 1-33, Inage-ku, Chiba 263-8522 (Japan); Kino, Motoki [National Astronomical Observatory of Japan, Mitaka 181-8588 (Japan); Nagakura, Hiroki [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)

2010-01-20

167

Hysteresis and nonlinear elasticity in rocks  

SciTech Connect

The purpose of this paper is to describe a theory of the propagation of elastic waves in hysteretic nonlinear elastic materials, e.g., rock. In the next section, we introduce the Priesach-Mayergoyz (P-M) model [6,7] of hysteretic systems and adapt it to describe the hysteretic mesoscopic elastic units (HMEU) determining the elastic properties of a rock. We combine the P-M model with effective medium theory (EMT) [8] to find the elastic response of a rock that has experienced a specified pressure history. Next, we consider elastic wave propagation in a hysteretic nonlinear elastic system governed by a history dependent equation of state. We consider one-dimensional propagation of compressional waves. The equation of motion for the longitudinal displacement field contains the same hysteretic nonlinear interactions that characterize the equation of state. We solve the equation of motion using the Green function technique developed by McCall [9]. This solution lets us identify the qualitative features in harmonic generation that are signatures of nonlinearity and hysteresis.

McCall, K.R.; Guyer, R.A.

1993-12-01

168

Hysteresis in the Central African Rainforest  

NASA Astrophysics Data System (ADS)

Past climate change caused severe disturbances of the Central African rainforest belt, with forest fragmentation and re-expansion due to drier and wetter climate conditions. Besides climate, human induced forest degradation affected biodiversity, structure and carbon storage of Congo basin rainforests. Information on climatically stable, mature rainforest, unaffected by human induced disturbances, provides means of assessing the impact of forest degradation and may serve as benchmarks of carbon carrying capacity over regions with similar site and climate conditions. BioGeoChemical (BGC) ecosystem models explicitly consider the impacts of site and climate conditions and may assess benchmark levels over regions devoid of undisturbed conditions. We will present a BGC-model validation for the Western Congolian Lowland Rainforest (WCLRF) using field data from a recently confirmed forest refuge, show model - data comparisons for disturbed und undisturbed forests under different site and climate conditions as well as for sites with repeated assessment of biodiversity and standing biomass during recovery from intensive exploitation. We will present climatic thresholds for WCLRF stability, analyse the relationship between resilience, standing C-stocks and change in climate and finally provide evidence of hysteresis.

Pietsch, Stephan Alexander; Elias Bednar, Johannes; Gautam, Sishir; Petritsch, Richard; Schier, Franziska; Stanzl, Patrick

2014-05-01

169

Hysteresis and transition in swirling nonpremixed flames  

SciTech Connect

Strongly swirling nonpremixed flames are known to exhibit a hysteresis when transiting from an attached long, sooty, yellow flame to a short lifted blue flame, and vice versa. The upward transition (by increasing the air and fuel flow rates) corresponds to a vortex breakdown, i.e. an abrupt change from an attached swirling flame (unidirectional or with a weak bluff-body recirculation), to a lifted flame with a strong toroidal vortex occupying the bulk of the flame. Despite dramatic differences in their structures, mixing intensities and combustion performance, both flame types can be realised at identical flow rates, equivalence ratio and swirl intensity. We report here on comprehensive investigations of the two flame regimes at the same conditions in a well-controlled experiment in which the swirl was generated by the rotating outer pipe of the annular burner air passage. Fluid velocity measured with PIV (particle image velocimetry), the qualitative detection of reaction zones from OH PLIF (planar laser-induced fluorescence) and the temperature measured by CARS (coherent anti-Stokes Raman spectroscopy) revealed major differences in vortical structures, turbulence, mixing and reaction intensities in the two flames. We discuss the transition mechanism and arguments for the improved mixing, compact size and a broader stability range of the blue flame in comparison to the long yellow flame. (author)

Tummers, M.J.; Huebner, A.W.; van Veen, E.H.; Hanjalic, K. [Delft University of Technology, Faculty of Applied Sciences, P.O. Box 5046, 2600 GA Delft (Netherlands); van der Meer, T.H. [University of Twente, Faculty of Engineering Technology, P.O. Box 217, 7500 AE Enschede (Netherlands)

2009-02-15

170

Contact angle hysteresis: a review of fundamentals and applications  

E-print Network

Contact angle hysteresis is an important physical phenomenon. It is omnipresent in nature and also plays a crucial role in various industrial processes. Despite its relevance, there is a lack of consensus on how to incorporate ...

’t Mannetje, D. J. C. M.

171

A high-speed hysteresis motor spindle for machining applications  

E-print Network

An analysis of suitable drive technologies for use in a new high-speed machining spindle was performed to determine critical research areas. The focus is on a hysteresis motor topology using a solid, inherently-balanced ...

Bayless, Jacob D. (Jacob Daniel)

2014-01-01

172

On the question of hysteresis in Hall magnetohydrodynamic reconnection  

SciTech Connect

Controversy has been raised regarding the cause of hysteresis, or bistability, of solutions to the equations that govern the geometry of the reconnection region in Hall magnetohydrodynamic (MHD) systems. This brief communication presents a comparison of the frameworks within which this controversy has arisen and illustrates that the Hall MHD hysteresis originally discovered numerically by Cassak et al. [Phys. Rev. Lett. 95, 235002 (2005)] is a different phenomenon from that recently reported by Zocco et al. [Phys. Plasmas 16, 110703 (2009)] on the basis of analysis and simulations in electron MHD with finite electron inertia. We demonstrate that the analytic prediction of hysteresis in EMHD does not describe or explain the hysteresis originally reported in Hall MHD, which is shown to persist even in the absence of electron inertia.

Sullivan, Brian P.; Bhattacharjee, A.; Huang Yimin [Center for Integrated Computation and Analysis of Reconnection and Turbulence, University of New Hampshire, Space Science Center, Durham, New Hampshire 03824 (United States)

2010-11-15

173

Magnetically suspended reaction sphere with one-axis hysteresis drive  

E-print Network

This thesis presents the design, modeling, implementation, and control of a magnetically suspended reaction sphere with one-axis hysteresis drive (1D-MSRS). The goal of this project is two fold: (a) exploring the design ...

Zhou, Lei., S.M. Massachusetts Institute of Technology

2014-01-01

174

Essays on crime, hysteresis, poverty and conditional cash transfers   

E-print Network

This thesis encompasses three essays around criminal behaviour with the first one analysing the impact of programmes aimed at poverty reduction, the second one developing a theoretical model of hysteresis in crime, and ...

Loureiro, Andre Oliveira Ferreira

2013-07-03

175

Dynamic wetting on superhydrophobic surfaces: Droplet impact and wetting hysteresis  

E-print Network

We study the wetting energetics and wetting hysteresis of sessile and impacting water droplets on superhydrophobic surfaces as a function of surface texture and surface energy. For sessile drops, we find three wetting ...

Smyth, Katherine M.

176

Could linear hysteresis contribute to shear wave losses in tissues?  

PubMed

For nearly 100 y in the study of cyclical motion in materials, a particular phenomenon called "linear hysteresis" or "ideal hysteretic damping" has been widely observed. More recently in the field of shear wave elastography, the basic mechanisms underlying shear wave losses in soft tissues are in question. Could linear hysteresis play a role? An underlying theoretical question must be answered: Is there a real and causal physical model that is capable of producing linear hysteresis over a band of shear wave frequencies used in diagnostic imaging schemes? One model that can approximately produce classic linear hysteresis behavior, by examining a generalized Maxwell model with a specific power law relaxation spectrum, is described here. This provides a theoretical plausibility for the phenomenon as a candidate for models of tissue behavior. PMID:25701527

Parker, Kevin J

2015-04-01

177

Cavitation level-acoustic intensity hysteresis: experimental and numerical characterization  

E-print Network

Cavitation level-acoustic intensity hysteresis: experimental and numerical characterization P cours Albert Thomas 69424 Lyon cedex 03 pauline.labelle@inserm.fr Proceedings of the Acoustics 2012 importance. When applying successive ultrasonic shots for increasing acoustic intensities, the inertial

Boyer, Edmond

178

Approximation properties of a PWL circuit model of hysteresis  

NASA Astrophysics Data System (ADS)

In this paper, some identification methods for a piece wise linear (PWL) circuit model of hysteresis phenomenon are presented and compared. The model provides a close prediction of static hysteresis and exhibits realistic dynamic features. The parameter identification problem can be solved by means of a suitable procedures based on representation theorem, on optimisation methods and on neural networks. Basic features are addressed and discussed.

Cincotti, Silvano

2000-01-01

179

Experimental Highlight of Hysteresis Phenomenon in Rolling Contact  

NASA Astrophysics Data System (ADS)

In literature, the hysteresis phenomenon in rolling contacts is studied considering both rolling friction and sliding friction. Removal of sliding friction in experimental tests from a concentrated contact is a serious challenge. The paper proposes a method and presents a device ensuring pure rolling between two identical discs, normally loaded. Using photoelastic material for the two rolling discs, by means of photoelastic method, the hysteresis phenomenon due to rolling friction is qualitatively confirmed.

Alaci, S.; Cerlinc?, D. A.; Ciornei, F. C.; Filote, C.; Frunz?, G.

2015-02-01

180

An undulation theory for condensation in open end slit pores: critical hysteresis temperature & critical hysteresis pore size.  

PubMed

A new theory of condensation in an open end slit pore, based on the concept of temperature dependent undulation, at the interface separating the adsorbed phase and the gas-like region, is presented. The theory, describes, for the first time, the microscopic origin of the critical hysteresis temperature and the critical hysteresis pore size, properties which are not accessible to any classical theories. PMID:24826906

Fan, Chunyan; Zeng, Yonghong; Do, D D; Nicholson, D

2014-06-28

181

Investigation of Fatigue Mechanisms in Pb(Zr, Ti)O3 Films from a Correlated Analysis of Hysteresis Parameters in a Lattice Model with Distributed Polarization Clamping  

Microsoft Academic Search

Several hypotheses concerning possible fatigue mechanisms have been implemented in the Landau theory-based lattice model for switching, and their suitability for explaining the fatigue of Pb(Zr, Ti)O3 films has been examined. A correlated analysis of the fatigue behavior of the hysteresis loop parameters has been shown to offer precise criteria for validating the fatigue scenarios and disclose the polarization state

Dan Ricinschi; Alexandru Ionut Lerescu; Masanori Okuyama

2000-01-01

182

Loop-to-loop coupling.  

SciTech Connect

This report estimates inductively-coupled energy to a low-impedance load in a loop-to-loop arrangement. Both analytical models and full-wave numerical simulations are used and the resulting fields, coupled powers and energies are compared. The energies are simply estimated from the coupled powers through approximations to the energy theorem. The transmitter loop is taken to be either a circular geometry or a rectangular-loop (stripline-type) geometry that was used in an experimental setup. Simple magnetic field models are constructed and used to estimate the mutual inductance to the receiving loop, which is taken to be circular with one or several turns. Circuit elements are estimated and used to determine the coupled current and power (an equivalent antenna picture is also given). These results are compared to an electromagnetic simulation of the transmitter geometry. Simple approximate relations are also given to estimate coupled energy from the power. The effect of additional loads in the form of attached leads, forming transmission lines, are considered. The results are summarized in a set of susceptibility-type curves. Finally, we also consider drives to the cables themselves and the resulting common-to-differential mode currents in the load.

Warne, Larry Kevin; Lucero, Larry Martin; Langston, William L.; Salazar, Robert Austin; Coleman, Phillip Dale; Basilio, Lorena I.; Bacon, Larry Donald

2012-05-01

183

Hydrological hysteresis and its value for assessing process consistency in catchment conceptual models  

NASA Astrophysics Data System (ADS)

While most hydrological models reproduce the general flow dynamics, they frequently fail to adequately mimic system-internal processes. In particular, the relationship between storage and discharge, which often follows annual hysteretic patterns in shallow hard-rock aquifers, is rarely considered in modelling studies. One main reason is that catchment storage is difficult to measure, and another one is that objective functions are usually based on individual variables time series (e.g. the discharge). This reduces the ability of classical procedures to assess the relevance of the conceptual hypotheses associated with models. We analysed the annual hysteric patterns observed between stream flow and water storage both in the saturated and unsaturated zones of the hillslope and the riparian zone of a headwater catchment in French Brittany (Environmental Research Observatory ERO AgrHys (ORE AgrHys)). The saturated-zone storage was estimated using distributed shallow groundwater levels and the unsaturated-zone storage using several moisture profiles. All hysteretic loops were characterized by a hysteresis index. Four conceptual models, previously calibrated and evaluated for the same catchment, were assessed with respect to their ability to reproduce the hysteretic patterns. The observed relationship between stream flow and saturated, and unsaturated storages led us to identify four hydrological periods and emphasized a clearly distinct behaviour between riparian and hillslope groundwaters. Although all the tested models were able to produce an annual hysteresis loop between discharge and both saturated and unsaturated storage, the integration of a riparian component led to overall improved hysteretic signatures, even if some misrepresentation remained. Such a system-like approach is likely to improve model selection.

Fovet, O.; Ruiz, L.; Hrachowitz, M.; Faucheux, M.; Gascuel-Odoux, C.

2015-01-01

184

Hydrological hysteresis in catchments and its value for assessing process consistency in conceptual models  

NASA Astrophysics Data System (ADS)

While most hydrological models reproduce the general flow dynamics, they frequently fail to adequately mimic system internal processes. In particular, the relationship between storage and discharge, which often follows annual hysteretic patterns in shallow hard-rock aquifers, is rarely considered in modelling studies. One main reason is that catchment storage is difficult to measure and another one is that objective functions are usually based on individual variables time series (e.g. the discharge). This reduces the ability of classical procedures to assess the relevance of the conceptual hypotheses associated with models. We analyzed the annual hysteric patterns observed between stream flow and water storage both in the saturated and unsaturated zones of the hillslope and the riparian zone of a headwater catchment in French Brittany (ORE AgrHys). The saturated zone storage was estimated using distributed shallow groundwater levels and the unsaturated zone storage using several moisture profiles. All hysteretic loops were characterized by a hysteresis index. Four conceptual models, previously calibrated and evaluated for the same catchment, were assessed with respect to their ability to reproduce the hysteretic patterns. The observed relationship between stream flow, saturated, and unsaturated storages led to identify four hydrological periods and emphasized a clearly distinct behaviour between riparian and hillslope groundwaters. Although all the tested models were able to produce an annual hysteresis loop between discharge and both saturated and unsaturated storage, integration of a riparian component led to overall improved hysteretic signatures, even if some misrepresentation remained. Such systems-like approach is likely to improve model selection.

Fovet, O.; Ruiz, L.; Hrachowitz, M.; Faucheux, M.; Gascuel-Odoux, C.

2014-05-01

185

Magnetic hysteresis properties of BaFe sub 12 minus x In sub x O sub 19 ceramic ferrites with c -axis oriented grains  

SciTech Connect

To study the effects of reduced magnetic anisotropy on hysteresis loops of hard magnets for possible use in self-biased microwave devices, a new family of magnetically oriented ({ital c}-axis) In-substituted Ba ferrite was prepared by conventional ceramic techniques. Earlier studies of BaFe{sub 12{minus}{ital x}}(In,Sc){sub {ital x}}O{sub 19} series in single-crystal form have shown that magnetization 4{pi}{ital M} and anisotropy field {ital H}{sub {ital k}} decrease sharply with increasing {ital x}. Since hysteresis loops with optimum energy products require uniformly small grains (1 to 3 {mu}m), sintering temperatures were carefully controlled over a range from 1180 to 1075 {degree}C for 2 h, depending on In content. For nominal values of {ital x} ranging from 0 to 1.5, square hysteresis loops with {ital H}{sub {ital c}} values decreasing from 3500 to 150 Oe were recorded with a high-field hysteresisgraph. The effective {ital H}{sub {ital k}} values were measured and compared with single-crystal data to estimate the degree of grain alignment for each composition.

Dionne, G.F.; Fitzgerald, J.F. (Lincoln Laboratory, Massachusetts Institute of Technology, P.O. Box 73, Lexington, Massachusetts (USA))

1991-11-15

186

Effects of Contact Angle Hysteresis on Ice Adhesion and Growth over Superhydrophobic Surfaces under Dynamic Flow Conditions  

SciTech Connect

In this paper, the iceophobic properties of superhydrophobic surfaces are investigated under dynamic flow conditions by using a closed loop low-temperature wind tunnel. Superhydrophobic surfaces were prepared by coating the substrates of aluminum and steel plates with nano-structured hydrophobic particles. The superhydrophobic plates along with uncoated control ones were exposed to an air flow of 12 m/s and 20 F accompanying micron-sized water droplets in the icing wind tunnel and the ice formation and accretion were probed by high-resolution CCD cameras. Results show that the superhydrophobic coatings significantly delay the ice formation and accretion even under the dynamic flow condition of the highly energetic impingement of accelerated super-cooled water droplets. It is found that there is a time scale for this phenomenon (delay of the ice formation) which has a clear correlation with the contact angle hysteresis and the length scale of surface roughness of the superhydrophobic surface samples, being the highest for the plate with the lowest contact angle hysteresis and finer surface roughness. The results suggest that the key parameter for designing iceophobic surfaces is to retain a low contact angle hysteresis (dynamic property) and the non-wetting superhydrophobic state under the hydrodynamic pressure of impinging droplets, rather than to only have a high contact angle (static property), in order to result in efficient anti-icing properties under dynamic conditions such as forced flows.

Sarshar, Mohammad Amin [Stevens Institute of Technology, Hoboken, New Jersey; Swarctz, Christopher [Stevens Institute of Technology, Hoboken, New Jersey; Hunter, Scott Robert [ORNL; Simpson, John T [ORNL; Choi, Chang-Hwan [Stevens Institute of Technology, Hoboken, New Jersey

2012-01-01

187

PREFACE: International Workshop on Multi-Rate Processes and Hysteresis  

NASA Astrophysics Data System (ADS)

We are interested in singular perturbation problems and hysteresis as common strongly nonlinear phenomena that occur in many industrial, physical and economic systems. The wording `strongly nonlinear' means that linearization will not encapsulate the observed phenomena. Often these two types of phenomena are manifested for different stages of the same or similar processes. A number of fundamental hysteresis models can be considered as limit cases of time relaxation processes, or admit an approximation by a differential equation which is singular with respect to a particular parameter. However, the amount of interaction between practitioners of theories of systems with time relaxation and systems with hysteresis (and between the `relaxation' and `hysteresis' research communities) is still low, and cross-fertilization is small. In recent years Ireland has become a home for a series of prestigious International Workshops in Singular Perturbations and Hysteresis: International Workshop on Multi-rate Processes and Hysteresis (University College Cork, Ireland, 3-8 April 2006). Proceedings are published in Journal of Physics: Conference Series, volume 55. See further information at http://euclid.ucc.ie/murphys2008.htm International Workshop on Hysteresis and Multi-scale Asymptotics (University College Cork, Ireland, 17-21 March 2004). Proceedings are published in Journal of Physics: Conference Series, volume 22. See further information at http://euclid.ucc.ie/murphys2006.htm International Workshop on Relaxation Oscillations and Hysteresis (University College Cork, Ireland, 1-6 April 2002). The related collection of invited lectures, was published as a volume Singular Perturbations and Hysteresis, SIAM, Philadelphia, 2005. See further information at http://euclid.ucc.ie/hamsa2004.htm International Workshop on Geometrical Methods of Nonlinear Analysis and Semiconductor Laser Dynamics (University College Cork, Ireland, 5-5 April 2001). A collection of invited papers has been published as a special issue of Proceedings of the Russian Academy of Natural Sciences: Nonlinear dynamics of laser and reacting systems, and is available online at http://www.ins.ucc.ie/roh2002.htm. See further information at http://www.ins.ucc.ie/roh2002.htm Among the aims of these workshops were to bring together leading experts in singular perturbations and hysteresis phenomena in applied problems; to discuss important problems in areas such as reacting systems, semiconductor lasers, shock phenomena in economic modelling, fluid mechanics, etc with an emphasis on hysteresis and singular perturbations; to learn and to share modern techniques in areas of common interest. The `International Workshop on Multi-Rate Processes and Hysteresis' (University College Cork, Ireland, April 3-8, 2006) brought together more than 70 scientists (including more than 10 students), actively researching in the areas of dynamical systems with hysteresis and singular perturbations, to analyze those phenomena that occur in many industrial, physical and economic systems. The countries represented at the Workshop included Czech Republic, England, France, Germany, Hungary, Ireland, Israel, Italy, Poland, Romania, Russia, Scotland, South Africa, Switzerland and USA. All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing. The Workshop has been sponsored by Science Foundation Ireland (SFI), KE Consulting group, Drexel University, Philadelphia, USA, University College Cork (UCC), Boole Centre for Research in Informatics, UCC, Cork, School of Mathematical Sciences, UCC, Cork, Irish Mathematical Society, Tyndall National Institute, Cork, University of Limerick, Cork Institute of Technology, and Heineken. The supportive affiliation of the European Geophysics Society, International Association of Hydrological Sciences, and Laboratoire Poncelet is grateful

Mortell, Michael P.; O'Malley, Robert E.; Pokrovskii, Alexei; Rachinskii, Dmitrii; Sobolev, Vladimir A.

2008-07-01

188

The origin of noise and hysteresis in permalloy ring-core fluxgate sensors  

NASA Astrophysics Data System (ADS)

in permalloy ring-core fluxgate sensors a single phenomenon may cause both fluxgate noise and magnetic hysteresis. It also provides an explanation for Barkhausen noise, remanence and coercivity. It can also resolve the "domain nucleation problem." in the unmagnetized state a high-quality permalloy foil takes a domain structure generally referred to as "stripe domains," which present at the free surface as parallel, uniformly spaced domain walls bounding regions of alternating 'in' and 'out' leakage flux, and domain walls crossing the entire thickness of the foil. The leakage flux is a requirement of the random orientation, grain-by-grain, of magnetic easy axes' angles with respect to the foil free surface, and creates a free space field with a magnetostatic energy cost. This together with domain wall energy determines an energy budget to be minimized. Throughout the magnetization cycle the free surface domain pattern remains essentially unchanged, due to the extreme magnetostatic energy cost such a change would elicit. Thus domain walls are 'pinned' to free surfaces. As the fluxgate core is driven to saturation, domain walls pinned at the free surfaces first bulge then reconnect to form a new domain configuration this author has called "channel domains", which are attached to free surfaces. Energy released during the domain wall reconnection manifests as Barkhausen noise, while the reconnection itself manifests as a Barkhausen jump. The approach to saturation now continues as reversible channel domain compression. Driving the permalloy into deep saturation will compress the channel domains to arbitrarily small thickness, but will not cause them to denucleate. Returning from saturation the channel domain structure will survive through zero drive H, thus explaining remanence. The Barkhausen jumps being irreversible, exothermic events are sources of fluxgate noise. It is also the case that fluxgate signal power is proportional to B-H loop curvature, that is to the second derivative of B. The degree to which Barkhausen jumps coincide with loop curvature is a measure of fluxgate noise that accompanies fluxgate signal. B-H loops with significant curvature beyond the open hysteresis loop may be used to advantage to acquire fluxgate signal with much reduced fluxgate noise.

Narod, Barry

2013-04-01

189

Joseph E. Gott, P.E. Chief Engineer and  

E-print Network

Joseph E. Gott, P.E. Chief Engineer and Director, Capital Improvements Naval Facilities Engineering Facilities Engineering Command's (NAVFAC) Chief Engineer and Director of Capital Improvements. As the Chief Engineer, he is the senior technical advisor for the Commander, NAVFAC, with respect to all engineering

190

Formative Assessment Probes: Using the P-E-O Technique  

ERIC Educational Resources Information Center

This article describes how observing whether objects sink or float in water using the P-E-O (Predict, Explain, and Observe) technique is an elementary precursor to developing explanations in later grades that involve an understanding of density and buoyancy. Beginning as early as preschool, elementary students engage in activities that encourage…

Keeley, Page

2013-01-01

191

Saturation overshoot and hysteresis for twophase flow in porous media  

NASA Astrophysics Data System (ADS)

Saturation overshoot and hysteresis for two phase flow in porous media are briefly reviewed. Old and new challenges are discussed. It is widely accepted that the traditional Richards model for twophase flow in porous media does not support non-monotone travelling wave solutions for the saturation profile. As a concequence various extensions and generalizations have been recently discussed. The review highlights different limits within the traditional theory. It emphasizes the relevance of hysteresis in the Buckley-Leverett limit with jump-type hysteresis in the relative permeabilities. Reviewing the situation it emerges that the traditional theory may have been abandoned prematurely because of its inability to predict saturation overshoot in the Richards limit.

Hilfer, R.; Steinle, R.

2014-10-01

192

Hysteresis Modeling in Magnetostrictive Materials Via Preisach Operators  

NASA Technical Reports Server (NTRS)

A phenomenological characterization of hysteresis in magnetostrictive materials is presented. Such hysteresis is due to both the driving magnetic fields and stress relations within the material and is significant throughout, most of the drive range of magnetostrictive transducers. An accurate characterization of the hysteresis and material nonlinearities is necessary, to fully utilize the actuator/sensor capabilities of the magnetostrictive materials. Such a characterization is made here in the context of generalized Preisach operators. This yields a framework amenable to proving the well-posedness of structural models that incorporate the magnetostrictive transducers. It also provides a natural setting in which to develop practical approximation techniques. An example illustrating this framework in the context of a Timoshenko beam model is presented.

Smith, R. C.

1997-01-01

193

Loop Algorithm  

NASA Astrophysics Data System (ADS)

The loop algorithm for the world-line quantum Monte Carlo method on quantum lattice models is presented. After introducing the path integral representation that maps a quantum model to a classical one, we describe the continuous imaginary time limit, cluster algorithm, and the rejection free scheme, which are the major improvements on the quantum Monte Carlo technique during the last decades. By means of the loop algorithm, one can simulate various unfrustrated quantum lattice models of millions of sites at extremely low temperatures with absolute accuracy, being free from the critical and fine-mesh slowing down and the Suzuki-Trotter discretization error. We also discuss some technical aspects of the algorithm such as effective implementation and parallelization.

Todo, Synge

194

Loop Diuretics  

Microsoft Academic Search

Loop diuretics such as furosemide, piretanide, and bumetanide bind reversibly to the Na+2Cl-K+ carrier. This transporter is responsible for the uptake of Cl- into the thick ascending limb segment. As a consequence, these compounds reduce or abolish NaCl reab-sorption in this nephron segment and lead to a decreased interstitial hypertonicity and thus to a reduced water absorption. Apart from these

R. Greger; P. Wangemann

1987-01-01

195

A self-adaptive genetic algorithm to estimate JA model parameters considering minor loops  

NASA Astrophysics Data System (ADS)

A self-adaptive genetic algorithm for estimating Jiles-Atherton (JA) magnetic hysteresis model parameters is presented. The fitness function is established based on the distances between equidistant key points of normalized hysteresis loops. Linearity function and logarithm function are both adopted to code the five parameters of JA model. Roulette wheel selection is used and the selection pressure is adjusted adaptively by deducting a proportional which depends on current generation common value. The Crossover operator is established by combining arithmetic crossover and multipoint crossover. Nonuniform mutation is improved by adjusting the mutation ratio adaptively. The algorithm is used to estimate the parameters of one kind of silicon-steel sheet's hysteresis loops, and the results are in good agreement with published data.

Lu, Hai-liang; Wen, Xi-shan; Lan, Lei; An, Yun-zhu; Li, Xiao-ping

2015-01-01

196

Hysteresis of magnetic force-gap in static and dynamic magnetic levitation with a high-{T_c} superconductor  

NASA Astrophysics Data System (ADS)

Hysteresis behavior of magnetic force versus gap between a high-Tc superconductor and a magnet, in static and dynamic cases, is studied numerically. Differing from the previous methods, based on macro electromagnetic constitutive relation of superconductors and Maxwell equations, a numerical method with the finite element method (FEM) is established. After numerical code is examined by comparing between numerical and experimental results of the relation of magnetic force-gap, the hysteresis curves of magnetic force-gap including major and minor loops in static case are simulated, and furthermore the dependences of major loop on main parameters including the critical current density and the thickness of superconductor, the residual magnetic field of magnet, and the diameter ratio of superconductor to magnet are studied numerically. In the case of free vibration, by investigating dynamic response of levitated body at different levitation/suspension positions in this magnetic levitation system, we obtain the corresponding results of the variation of magnetic force with gap. All the numerical results of the relation between magnetic force and gap show the strongly nonlinear and highly hysteretic behavior.

Gou, X.-F.; Zhang, Z.-X.

2008-11-01

197

A digitally linear piezoelectric bimorph actuator in open-loop mode  

NASA Astrophysics Data System (ADS)

The current paper reports a digital piezoelectric bimorph actuator having segmented electrodes and producing 2 to the nth power digital bending actuation in on/off switch mode and under a fix applied voltage. Correspondingly, a simple model for predicting digital actuation under applied coding voltage is also presented. Experimental results have confirmed that the proposed actuator can produce a linear digital displacement without a hysteresis loop. The proposed method is significant for open-loop high precise actuation.

Xiao, Wenlei; Huan, Ji; Liu, Guoxi; Shi, Huaduo; Dong, Shuxiang

2013-03-01

198

Enhanced ferroelectric loop asymmetry of lead zirconate titanate thin films under nanoindentation  

NASA Astrophysics Data System (ADS)

The effect of mechanical stress on the local switching behavior and hysteresis properties of Pb(Zr ,Ti)O3 and Mn-doped Pb(Zr ,Ti)O3 ferroelectric thin films has been studied using spherical nanoindentation. A conductive WC-Co cermet indenter tip of 500?m nominal radius was employed in a modified nanoindentation system to allow the simultaneous application of driving voltage and mechanical loading, and consequently to collect the ferroelectric charge developed on thin films without a top electrode. Instrumented progressive indentation caused an enhancement of hysteresis loop deformations. The charge released versus applied voltage (Q-V) hysteresis loops gradually shifted along the voltage axis with increasing indentation force. Also, an enhanced vertical shift and hysteresis gap of the Q-V loops was observed. The parameter of horizontal loop asymmetry (? ) increased almost linearly with the force by an increment of about (0.4-0.5)×10-3/100mN with a 50V peak drive voltage and a 50Hz sinusoidal wave form. The effect of nanoindentation on polarization reversal in thin ferroelectric films is suggested to result from a variation in residual stress state, asymmetric distribution of charged defects, and asymmetric lattice distortion produced by the inhomogeneous indentation stress field.

Koval, V.; Reece, M. J.; Bushby, A. J.

2007-01-01

199

Comparative analysis of closed-loop current control of grid connected converter with LCL filter  

Microsoft Academic Search

Voltage source inverters (VSIs) with output LCL filters are the key interfaces for today's distributed energy resource. There are mainly two groups of current control methods of a VSI: direct error tracking control with PWM, and closed-loop feedback control. Direct current error control, such as predictive control and hysteresis control, has some drawbacks like system parameter sensitivity, variable switching frequency,

Jinwei He; Yun Wei Li

2011-01-01

200

Molecular Origin and Functional Consequences of Digital Signaling and Hysteresis During Ras Activation in Lymphocytes  

NSDL National Science Digital Library

Activation of Ras proteins underlies functional decisions in diverse cell types. Two molecules, Ras-GRP and SOS (Ras–guanine nucleotide–releasing protein and Son of Sevenless, respectively), catalyze Ras activation in lymphocytes. Binding of active Ras to the allosteric pocket of SOS markedly increases the activity of SOS. Thus, there is a positive feedback loop regulating SOS. Combining in silico and in vitro studies, we demonstrate that “digital” signaling in lymphocytes (cells are “on” or “off”) is predicated on this allosteric regulation of SOS. The SOS feedback loop leads to hysteresis in the dose-response curve, which may enable T cells to exhibit “memory” of past encounters with antigen. Ras activation by Ras-GRP alone is “analog” (a graded increase in activation in response to an increase in the amplitude of the stimulus). We describe how the complementary analog (Ras-GRP) and digital (SOS) pathways act on Ras to efficiently convert analog input to digital output and make predictions regarding the importance of digital signaling in lymphocyte function and development.

Arup K. Chakraborty (Massachusetts Institute of Technology; Department of Chemical Engineering; REV)

2009-04-14

201

Molecular origin and functional consequences of digital signaling and hysteresis during Ras activation in lymphocytes.  

PubMed

Activation of Ras proteins underlies functional decisions in diverse cell types. Two molecules, Ras-GRP and SOS (Ras-guanine nucleotide-releasing protein and Son of Sevenless, respectively), catalyze Ras activation in lymphocytes. Binding of active Ras to the allosteric pocket of SOS markedly increases the activity of SOS. Thus, there is a positive feedback loop regulating SOS. Combining in silico and in vitro studies, we demonstrate that "digital" signaling in lymphocytes (cells are "on" or "off") is predicated on this allosteric regulation of SOS. The SOS feedback loop leads to hysteresis in the dose-response curve, which may enable T cells to exhibit "memory" of past encounters with antigen. Ras activation by Ras-GRP alone is "analog" (a graded increase in activation in response to an increase in the amplitude of the stimulus). We describe how the complementary analog (Ras-GRP) and digital (SOS) pathways act on Ras to efficiently convert analog input to digital output and make predictions regarding the importance of digital signaling in lymphocyte function and development. PMID:19366993

Chakraborty, Arup K; Das, Jayajit; Zikherman, Julie; Yang, Ming; Govern, Christopher C; Ho, Mary; Weiss, Arthur; Roose, Jeroen

2009-01-01

202

Wetting hysteresis and droplet roll off behavior on superhydrophobic surfaces by Katherine Marie Smyth.  

E-print Network

Various states of hydrophobic wetting and hysteresis are observed when water droplets are deposited on micro-post surfaces of different post densities. Hysteresis is commonly defined as the difference between the advancing ...

Smyth, Katherine Marie

2010-01-01

203

Butterfly hysteresis loop at nonzero bias field in antiferromagnetic molecular rings: cooling by adiabatic magnetization.  

PubMed

At low temperatures, the magnetization of the molecular ferric wheel NaFe6 exhibits a step at a critical field B(c) due to a field-induced level crossing. By means of high-field torque magnetometry we observed a hysteretic behavior at the level crossing with a characteristic butterfly shape which is analyzed in terms of a dissipative two-level model. Several unusual features were found. The nonzero bias field of the level crossing suggests the possibility of cooling by adiabatic magnetization. PMID:12484964

Waldmann, O; Koch, R; Schromm, S; Müller, P; Bernt, I; Saalfrank, R W

2002-12-01

204

Causes and implications of colloid and microorganism retention hysteresis  

Technology Transfer Automated Retrieval System (TEKTRAN)

Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1...

205

Idealized Hysteresis Modeling of Electrorheological and Magnetorheological Dampers  

Microsoft Academic Search

The hysteresis behavior of a linear stroke magnetorheological damper is characterized for sinusoidal displacement excitation at 2.0 Hz (nominal). Four different modeling perspectives are discussed for purposes of system identification procedures, including: (1) equivalent viscous damping, (2) nonlinear Bingham plastic model, (3) nonlinear biviscous model, and (4) nonlinear hysteretic biviscous model. By progressively adding model parameters with which to better

Norman M. Wereley; Li Pang; Gopalakrishna M. Kamath

1998-01-01

206

Modeling of a Magnetorheological Actuator Including Magnetic Hysteresis  

Microsoft Academic Search

Magnetorheological (MR) actuators provide controlled torque through control of an applied magnetic field. Therefore knowledge of the relationship between the applied current and output torque is required. This paper presents a new nonlinear modeling of MR actuators considering magnetic hysteresis to determine the torque-current nonlinear relationship. Equations for transmitted torque are derived according to mechanical shear configurations of the MR

Jinung An; Dong-Soo Kwon

2003-01-01

207

Hysteresis heating based induction bonding of composite materials  

Microsoft Academic Search

The viability of using magnetic particulate susceptor materials for induction heating during bonding of polymer matrix composites is well established in this work. The unique ability to offer localized heating, geometric flexibility, and self-controlled temperature is the major advantage of this technique. Hysteresis heating is tailored through careful design of the microstructure of nickel particulate polymer films (Ni\\/PSU). An excellent

Witchuda Suwanwatana

2004-01-01

208

Similarity Hypothesis for Capillary Hysteresis in Porous Materials  

Microsoft Academic Search

A quantitative description of the capillary hysteresis properties of a porous ma- terial is developed through bivariate distribution density function f(a, ), where a andare wetting and drying potentials. This is formally equivalent to the independent domain theory of Poulovassilis. The similarity hypothesis ' (implying, loosely, that the distribution of geometrical relationships between wetting and drying meniscus curvatures is independent

J. R. Philip

1964-01-01

209

Hysteresis during lithium insertion in hydrogen-containing carbons  

Microsoft Academic Search

The authors studied lithium insertion in hydrogen-containing carbons heated at temperatures near 700 C. High capacities with large hysteresis (lithium insertion into these carbons at nearly 0 V and removal at nearly 1 V) were shown to be proportional to the hydrogen content of the samples. It is believed that the lithium atoms may bind on hydrogen-terminated edges of hexagonal

Tao Zheng; J. R. Dahn; W. R. McKinnon

1996-01-01

210

Dynamic contact angles and hysteresis under electrowetting-on-dielectric.  

PubMed

By designing and implementing a new experimental method, we have measured the dynamic advancing and receding contact angles and the resulting hysteresis of droplets under electrowetting-on-dielectric (EWOD). Measurements were obtained over wide ranges of applied EWOD voltages, or electrowetting numbers (0 ? Ew ? 0.9), and droplet sliding speeds, or capillary numbers (1.4 × 10(-5) ? Ca ? 6.9 × 10(-3)). If Ew or Ca is low, dynamic contact angle hysteresis is not affected much by the EWOD voltage or the sliding speed; that is, the hysteresis increases by less than 50% with a 2 order-of-magnitude increase in sliding speed when Ca < 10(-3). If both Ew and Ca are high, however, the hysteresis increases with either the EWOD voltage or the sliding speed. Stick-slip oscillations were observed at Ew > 0.4. Data are interpreted with simplified hydrodynamic (Cox-Voinov) and molecular-kinetic theory (MKT) models; the Cox-Voinov model captures the trend of the data, but it yields unreasonable fitting parameters. MKT fitting parameters associated with the advancing contact line are reasonable, but a lack of symmetry indicates that a more intricate model is required. PMID:21751778

Nelson, Wyatt C; Sen, Prosenjit; Kim, Chang-Jin C J

2011-08-16

211

A Domain Wall Model for Hysteresis in Ferroelastic Materials  

E-print Network

with experimental stress-strain data. Keywords: Ferroelastic hysteresis; shape memory alloy; domain wall theory; ferroelastic domain; superelasticity; Landau theory of phase transitions;anyhysteretic strain; domain wall the model in two steps. First, we use the Landau theory of phase transitions to characterize the effective

212

A Domain Wall Model for Hysteresis in Ferroelastic Materials  

E-print Network

with experimental stress­strain data. Keywords: Ferroelastic hysteresis; shape memory alloy; domain wall theory; ferroelastic domain; superelasticity; Landau theory of phase transitions;anyhysteretic strain; domain wall the model in two steps. First, we use the Landau theory of phase transitions to characterize the e

213

Hysteresis compensation of piezoelectric actuators: the modified Rayleigh model.  

PubMed

In this study, we develop a novel modified Rayleigh model for hysteresis compensation in piezoelectric actuators. Piezoelectric actuators suffer from hysteresis, in large drive fields of more than 100 V, which can result in serious displacement errors. The typical phenomenological approach is to use the Rayleigh model; however, this model gives more than 10% difference with experiments at the large electric fields of more than 1kV/mm. Furthermore, there are no studies that apply the Rayleigh model to the compensation of precision actuators, such as stack actuators; it has only been applied in the study of the physical properties of piezoelectric materials. Therefore, we propose a modified Rayleigh model, in which each coefficient is defined differently according to whether the field is increasing or decreasing to account for asymmetry at the high fields. By applying a computer-based control from an inverse form of this modified Rayleigh model, we show that we can compensate for hysteresis to reduce the position error to less than five percent. This model has the merits of reducing complicated fitting procedures and of saving computation time compared to the Preisach model. Specifically, this model cannot only predict the hysteresis curves in all local fields using only one fitting procedure, but also make it possible to control the displacement of various piezo-based actuators without expensive sensors, based on the charge-based model. PMID:19939427

Park, Jongkyu; Moon, Wonkyu

2010-03-01

214

Rainflow Counting and Energy Dissipation for Hysteresis Models in Elastoplasticity  

E-print Network

Rainflow Counting and Energy Dissipation for Hysteresis Models in Elastoplasticity Martin Brokate Republic Abstract The rainflow counting method is widely used in the context of fatigue analy- sis for some remarks, we exclusively deal with the uniaxial case. Running title. Rainflow Counting and Energy

Krejcí, Pavel

215

Hysteresis and reluctance electric machines with bulk HTS rotor elements  

Microsoft Academic Search

Two new types of HTS electric machines are considered. The first type is hysteresis motors and generators with cylindrical and disk rotors containing bulk HTS elements. The second type is reluctance motors with compound HTS-ferromagnetic rotors. The compound HTS-ferromagnetic rotors, consisting of joined alternating bulk HTS (YBCO) and ferromagnetic (iron) plates, provide a new active material for electromechanical purposes. Such

L. K. Kovalev; K. V. Ilushin; S. M.-A. Koneev; K. L. Kovalev; V. T. Penkin; V. N. Poltavets; W. Gawalek; T. Habisreuther; B. Oswald; K.-J. Best

1999-01-01

216

Hysteresis electrical motors with bulk melt-textured YBCO  

Microsoft Academic Search

New types of electrical motors based on bulk high temperature superconductors (HTS) are presented. Theoretical and experimental research of these motors is described. Results for a series of 100, 300, 500 and 1000 W HTS motors with cylindrical and disk rotors are presented. It is shown that, at liquid nitrogen temperatures, the specific mass-dimension parameter of hysteresis HTS machines is

L. K. Kovalev; K. V. Ilushin; V. T. Penkin; K. L. Kovalev; V. S. Semenikhin; V. N. Poltavets; A. E. Larionoff; W. Gawalek; T. Habisreuther; T. Strasser; A. K. Shikov; E. G. Kazakov; V. V. Alexandrov

1998-01-01

217

Friction and Adhesion Hysteresis between Surfactant Monolayers in Water  

E-print Network

Friction and Adhesion Hysteresis between Surfactant Monolayers in Water Wuge H. Briscoe Physical with a double-chained quaternary ammonium surfactant in intimate adhesive contact in water. This enables us to propose a mechanism for surfactant boundary lubrication in water that is rather different from the classic

Klein, Jacob

218

A novel SVM-based hysteresis current controller  

Microsoft Academic Search

In this paper, a novel space vector modulation (SVM)-based hysteresis current controller (HCC) for squirrel cage induction motors is proposed. This technique utilizes all advantages of the HCC and SVM technique. The controller determines a set of space vectors from a region detector and applies a space vector selected according to the main HCC. A set of space vectors including

Bong-Hwan Kwon; Tae-Woo Kim; Jang-Hyoun Youm

1998-01-01

219

M-H loop tracer based on digital signal processing for low frequency characterization of extremely thin magnetic wires  

SciTech Connect

A high-sensitivity ac hysteresis loop tracer has been developed to measure the low frequency hysteresis loop of soft magnetic materials. It has been applied successfully to characterize straight pieces of amorphous glass-covered microwires with metallic nucleus down to 1.5 {mu}m thick. Based on the electromagnetic induction law, the proposed design is extremely simple and exploits the capabilities of commercially available data acquisition cards together with digital signal processing in order to achieve high-sensitivity without the need of expensive analog equipment.

Butta, M.; Ripka, P. [Department of Measurement, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague 16627 (Czech Republic); Infante, G.; Badini-Confalonieri, G. A.; Vazquez, M. [Instituto de Ciencia de Materiales de Madrid (CSIC), Campus de Cantoblanco, Madrid 28049 (Spain)

2009-08-15

220

Adsorption/desorption hysteresis in the adsorption isotherms for Kr and Xe on exfoliated graphite  

NASA Astrophysics Data System (ADS)

The adsorption/desorption hysteresis which appears in the adsorption isotherm for Kr physisorbed on exfoliated graphite has a very characteristic feature. A sharp transition at the termination of the hysteresis in the desorption branch of the isotherm suggests a first-order phase transition. The temperature dependence of the hysteresis for Kr and Xe on exfoliated graphite was investigated. The origin of the hysteresis of Kr is thought to be capillary condensation accompanied by a liquid-solid phase transition.

Kosugi, T.; Usui, Y.; Arakawa, I.

1993-05-01

221

Hysteresis in the dynamic perception of scenes and objects.  

PubMed

Scenes and objects are effortlessly processed and integrated by the human visual system. Given the distinct neural and behavioral substrates of scene and object processing, it is likely that individuals sometimes preferentially rely on one process or the other when viewing canonical "scene" or "object" stimuli. This would allow the visual system to maximize the specific benefits of these 2 types of processing. It is less obvious which of these modes of perception would be invoked during naturalistic visual transition between a focused view of a single object and an expansive view of an entire scene, particularly at intermediate views that may not be assigned readily to either stimulus category. In the current study, we asked observers to report their online perception of such dynamic image sequences, which zoomed and panned between a canonical view of a single object and an entire scene. We found a large and consistent effect of prior perception, or hysteresis, on the classification of the sequence: observers classified the sequence as an object for several seconds longer if the trial started at the object view and zoomed out, whereas scenes were perceived for longer on trials beginning with a scene view. This hysteresis effect resisted several manipulations of the movie stimulus and of the task performed, but hinged on the perceptual history built by unidirectional progression through the image sequence. Multiple experiments confirmed that this hysteresis effect was not purely decisional and was more prominent for transitions between corresponding objects and scenes than between other high-level stimulus classes. This finding suggests that the competitive mechanisms underlying hysteresis may be especially prominent in the perception of objects and scenes. We propose that hysteresis aids in disambiguating perception during naturalistic visual transitions, which may facilitate a dynamic balance between scene and object processing to enhance processing efficiency. PMID:25150947

Poltoratski, Sonia; Tong, Frank

2014-10-01

222

Partial and full inverse compensation for hysteresis in smart material systems  

Microsoft Academic Search

Smart material transducers employing piezoceramic or magnetostrictive drive components typically exhibit constitutive nonlinearities and hysteresis at moderate to high drive levels. In this paper, we discuss two techniques to compensate for hysteresis in high performance transducers. The first is based on a complete transducer model, and the resulting compensator accommodates both the constitutive nonlinearities and hysteresis inherent to the smart

Ralph C. Smith; C. Bouron; Rick Zrostlik

2000-01-01

223

Finite element analysis of hysteresis motor using the vector magnetization-dependent model  

Microsoft Academic Search

This paper presents a finite element analysis procedure combined with a vector hysteresis model for the accurate analysis of an hysteresis motor. The vector magnetization-dependent model is adopted to calculate the vector magnetization of the hysteresis ring. From the magnitude and direction of the magnetic field intensity, the magnetization of each ring element is calculated by the vector model. By

Hong-Kyu Kim; Hyun-Kyo Jung; Sun-Ki Hong

1998-01-01

224

Tracking control of a piezoceramic actuator with hysteresis compensation using inverse Preisach model  

Microsoft Academic Search

This paper presents the classical Preisach hysteresis modeling and tracking control of a curved pre-stressed piezoceramic patch actuator system with severe hysteresis. The actuator is also flexible with very small inherent damping. It has potential applications in active antennas. A series of tests are conducted to study the hysteresis properties of the piezoceramic actuator system. The numerical expressions of the

G. Song; Jinqiang Zhao; Xiaoqin Zhou; J. Alexis De Abreu-García

2005-01-01

225

Adaptive variable structure control of a class of nonlinear systems with unknown Prandtl-Ishlinskii hysteresis  

Microsoft Academic Search

Control of nonlinear systems preceded by unknown hysteresis nonlinearities is a challenging task and has received increasing attention in recent years due to growing industrial demands involving varied applications. In the literature, many mathematical models have been proposed to describe the hysteresis nonlinearities. The challenge addressed here is how to fuse those hysteresis models with available robust control techniques to

Chun-Yi Su; Qingqing Wang; Xinkai Chen; Subhash Rakheja

2005-01-01

226

Back-propagation operation for analog neural network hardware with synapse components having hysteresis characteristics.  

PubMed

To realize an analog artificial neural network hardware, the circuit element for synapse function is important because the number of synapse elements is much larger than that of neuron elements. One of the candidates for this synapse element is a ferroelectric memristor. This device functions as a voltage controllable variable resistor, which can be applied to a synapse weight. However, its conductance shows hysteresis characteristics and dispersion to the input voltage. Therefore, the conductance values vary according to the history of the height and the width of the applied pulse voltage. Due to the difficulty of controlling the accurate conductance, it is not easy to apply the back-propagation learning algorithm to the neural network hardware having memristor synapses. To solve this problem, we proposed and simulated a learning operation procedure as follows. Employing a weight perturbation technique, we derived the error change. When the error reduced, the next pulse voltage was updated according to the back-propagation learning algorithm. If the error increased the amplitude of the next voltage pulse was set in such way as to cause similar memristor conductance but in the opposite voltage scanning direction. By this operation, we could eliminate the hysteresis and confirmed that the simulation of the learning operation converged. We also adopted conductance dispersion numerically in the simulation. We examined the probability that the error decreased to a designated value within a predetermined loop number. The ferroelectric has the characteristics that the magnitude of polarization does not become smaller when voltages having the same polarity are applied. These characteristics greatly improved the probability even if the learning rate was small, if the magnitude of the dispersion is adequate. Because the dispersion of analog circuit elements is inevitable, this learning operation procedure is useful for analog neural network hardware. PMID:25393715

Ueda, Michihito; Nishitani, Yu; Kaneko, Yukihiro; Omote, Atsushi

2014-01-01

227

Back-Propagation Operation for Analog Neural Network Hardware with Synapse Components Having Hysteresis Characteristics  

PubMed Central

To realize an analog artificial neural network hardware, the circuit element for synapse function is important because the number of synapse elements is much larger than that of neuron elements. One of the candidates for this synapse element is a ferroelectric memristor. This device functions as a voltage controllable variable resistor, which can be applied to a synapse weight. However, its conductance shows hysteresis characteristics and dispersion to the input voltage. Therefore, the conductance values vary according to the history of the height and the width of the applied pulse voltage. Due to the difficulty of controlling the accurate conductance, it is not easy to apply the back-propagation learning algorithm to the neural network hardware having memristor synapses. To solve this problem, we proposed and simulated a learning operation procedure as follows. Employing a weight perturbation technique, we derived the error change. When the error reduced, the next pulse voltage was updated according to the back-propagation learning algorithm. If the error increased the amplitude of the next voltage pulse was set in such way as to cause similar memristor conductance but in the opposite voltage scanning direction. By this operation, we could eliminate the hysteresis and confirmed that the simulation of the learning operation converged. We also adopted conductance dispersion numerically in the simulation. We examined the probability that the error decreased to a designated value within a predetermined loop number. The ferroelectric has the characteristics that the magnitude of polarization does not become smaller when voltages having the same polarity are applied. These characteristics greatly improved the probability even if the learning rate was small, if the magnitude of the dispersion is adequate. Because the dispersion of analog circuit elements is inevitable, this learning operation procedure is useful for analog neural network hardware. PMID:25393715

Ueda, Michihito; Nishitani, Yu; Kaneko, Yukihiro; Omote, Atsushi

2014-01-01

228

Inverse open-loop control of a nano-positioner based on piezo-electric actuators  

NASA Astrophysics Data System (ADS)

Piezo-electric actuators with advantage of fast responsiveness, large force output, low power consumption, negligible friction and no backlash are widely used in precision positioning, adaptive optics and vibration conduction. However its inherent hysteresis brings difficulty to high precision positioning. To describe the hysteresis, a mathematical model based on experimental data is used. And the inverse of the model is connected to the piezo-electric actuator as a controller to compensating the hysteresis. In this paper KP operator is used to model the hysteresis of piezo-electric actuators and a numerical algorithm is proposed to compute the inverse. Experiments data of major hysteresis loop and minor loop collected on a nano-positioning stage are used to identify the model ? based on which the inverse model ?-1 is developed. Experiments show that given a voltage series the model ? can give displacement prediction which has an error of 6% relative to experimental results and ?-1 can give voltage prediction with the error of 5% relative to the experimental data.

Qiang, Shu; Rao, Xuejun; Shi, Ningping

2012-10-01

229

Enhanced hysteresis in the semiconductor-to-metal phase transition of VO2 precipitates formed in SiO2 by ion implantation  

NASA Astrophysics Data System (ADS)

A strongly enhanced hysteresis with a width of >34 °C has been observed in the semiconductor-to-metal phase transition of submicron-scale VO2 precipitates formed in the near-surface region of amorphous SiO2 by the stoichiometric coimplantation of vanadium and oxygen and subsequent thermal processing. This width is approximately an order of magnitude larger than that reported previously for the phase transition of VO2 particles formed in Al2O3 by a similar technique. The phase transition is accompanied by a significant change in infrared transmission. The anomalously wide hysteresis loop observed here for the VO2/SiO2 system can be exploited in optical data storage and switching applications in the infrared region.

Lopez, R.; Boatner, L. A.; Haynes, T. E.; Haglund, R. F.; Feldman, L. C.

2001-11-01

230

Method of thermal strain hysteresis reduction in metal matrix composites  

NASA Technical Reports Server (NTRS)

A method is disclosed for treating graphite reinforced metal matrix composites so as to eliminate thermal strain hysteresis and impart dimensional stability through a large thermal cycle. The method is applied to the composite post fabrication and is effective on metal matrix materials using graphite fibers manufactured by both the hot roll bonding and diffusion bonding techniques. The method consists of first heat treating the material in a solution anneal oven followed by a water quench and then subjecting the material to a cryogenic treatment in a cryogenic oven. This heat treatment and cryogenic stress reflief is effective in imparting a dimensional stability and reduced thermal strain hysteresis in the material over a -250.degree. F. to +250.degree. F. thermal cycle.

Dries, Gregory A. (Inventor); Tompkins, Stephen S. (Inventor)

1987-01-01

231

Hysteresis and Kinetic Effects During Liquid-Solid Transitions  

SciTech Connect

We address the fundamental issue of phase transition kinetics in dynamically compressed materials. Focusing on solid bismuth (Bi) as a prototype material, we used a variety of time-resolved experiments including electrical conductivity and velocimetry to study the phase transition kinetics of the solid-solid phase transitions. Simple single shock experiments performed on several low-lying high pressure phases of Bi, revealed surprisingly complex behavior and slow dynamics. Strong hysteresis effects were observed in the transition behavior in experiments where the compressed Bi was allowed to release back across a phase line. These experiments represent the first reported simultaneous use of resistivity and velocimetry in a shock compression experiment, and the first observation of hysteresis effects occurring during dynamic compression and release.

Streitz, F H; Chau, R

2009-02-17

232

Efficiency of Hysteresis Rods in Small Spacecraft Attitude Stabilization  

PubMed Central

A semiempirical method for predicting the damping efficiency of hysteresis rods on-board small satellites is presented. It is based on the evaluation of dissipating energy variation of different ferromagnetic materials for two different rod shapes: thin film and circular cross-section rods, as a function of their elongation. Based on this formulation, an optimum design considering the size of hysteresis rods, their cross section shape, and layout has been proposed. Finally, the formulation developed was applied to the case of four existing small satellites, whose corresponding in-flight data are published. A good agreement between the estimated rotational speed decay time and the in-flight data has been observed. PMID:24501579

Farrahi, Assal; Sanz-Andrés, Ángel

2013-01-01

233

Attachment/detachment hysteresis of fiber-based magnetic grabbers.  

PubMed

We developed an experimental protocol to analyze the behaviour of a model fiber-based magnetic grabber. A fiber is vertically suspended and fixed to the substrate by its upper end. A magnetic droplet is attached to the free end of the fiber and when a permanent magnet approaches the droplet, the fiber is forced to bow and finally jumps to the magnet. It appears that one can flex the micro-fibers by very small micro or even nano-Newton forces. Using this setup, we discovered a hysteresis of fiber attachment/detachment: the pathway of the fiber jumping to and off the magnet depends on the distance between the magnet and the clamped end. This phenomenon was successfully explained by the Euler-Benoulli model of an elastic beam. The observed hysteresis of fiber attachment/detachment was attributed to the multiple equilibrium configurations of the fiber tip placed in a dipole-type magnetic field. PMID:24668160

Gu, Yu; Kornev, Konstantin G

2014-04-28

234

Water Stream "Loop-the-Loop"  

ERIC Educational Resources Information Center

Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)

Jefimenko, Oleg

1974-01-01

235

Degradation and capacitance: voltage hysteresis in CdTe devices  

NASA Astrophysics Data System (ADS)

CdS/CdTe photovoltaic solar cells were made on two different transparent conducting oxide (TCO) structures in order to identify differences in fabrication, performance, and reliability. In one set of cells, chemical vapor deposition (CVD) was used to deposit a bi-layer TCO on Corning 7059 borosilicate glass consisting of a F-doped, conductive tin-oxide (cSnO2) layer capped by an insulating (undoped), buffer (iSnO2) layer. In the other set, a more advanced bi-layer structure consisting of sputtered cadmium stannate (Cd2SnO4; CTO) as the conducting layer and zinc stannate (Zn2SnO4; ZTO) as the buffer layer was used. CTO/ZTO substrates yielded higher performance devices however performance uniformity was worse due to possible strain effects associated with TCO layer fabrication. Cells using the SnO2-based structure were only slightly lower in performance, but exhibited considerably greater performance uniformity. When subjected to accelerated lifetime testing (ALT) at 85 - 100 °C under 1-sun illumination and open-circuit bias, more degradation was observed in CdTe cells deposited on the CTO/ZTO substrates. Considerable C-V hysteresis, defined as the depletion width difference between reverse and forward direction scans, was observed in all Cu-doped CdTe cells. These same effects can also be observed in thin-film modules. Hysteresis was observed to increase with increasing stress and degradation. The mechanism for hysteresis is discussed in terms of both an ionic-drift model and one involving majority carrier emission in the space-charge region (SCR). The increased generation of hysteresis observed in CdTe cells deposited on CTO/ZTO substrates suggests potential decomposition of these latter oxides when subjected to stress testing.

Albin, D. S.; Dhere, R. G.; Glynn, S. C.; del Cueto, J. A.; Metzger, W. K.

2009-08-01

236

Hysteresis effects of changing the parameters of noncooperative games  

NASA Astrophysics Data System (ADS)

We adapt the method used by Jaynes to derive the equilibria of statistical physics to instead derive equilibria of bounded rational game theory. We analyze the dependence of these equilibria on the parameters of the underlying game, focusing on hysteresis effects. In particular, we show that by gradually imposing individual-specific tax rates on the players of the game, and then gradually removing those taxes, the players move from a poor equilibrium to one that is better for all of them.

Wolpert, David H.; Harré, Michael; Olbrich, Eckehard; Bertschinger, Nils; Jost, Jürgen

2012-03-01

237

Model-Based, Closed-Loop Control of PZT Creep for Cavity Ring-Down Spectroscopy.  

PubMed

Cavity ring-down spectrometers typically employ a PZT stack to modulate the cavity transmission spectrum. While PZTs ease instrument complexity and aid measurement sensitivity, PZT hysteresis hinders the implementation of cavity-length-stabilized, data-acquisition routines. Once the cavity length is stabilized, the cavity's free spectral range imparts extreme linearity and precision to the measured spectrum's wavelength axis. Methods such as frequency-stabilized cavity ring-down spectroscopy have successfully mitigated PZT hysteresis, but their complexity limits commercial applications. Described herein is a single-laser, model-based, closed-loop method for cavity length control. PMID:25395738

McCartt, A D; Ognibene, T J; Bench, G; Turteltaub, K W

2014-09-01

238

Tuning size and thermal hysteresis in bistable spin crossover nanoparticles.  

PubMed

Nanoparticles of iron(II) triazole salts have been prepared from water-organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30-40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10-15 nm, the spin transition "moves" towards lower temperatures, reaching a 316 K limit for the cooling down transition and maintaining a thermal hysteresis over 15-20-K-wide. The nanoparticles were characterized by dynamic light scattering, TEM, and AFM, after deposition on gold or silicon surfaces. The spin transition was characterized by magnetic susceptibility measurements and EXAFS (in solid samples after solvent removal) and also by the color change between the LS (violet) and HS (colorless) states in an organic solvent suspension. The discovery of bistable magnetic nanoparticles of 6 nm with a wide thermal hysteresis above room temperature showcases the actual possibilities of spin crossover materials for nanotechnological applications. PMID:20503990

Galán-Mascarós, José Ramón; Coronado, Eugenio; Forment-Aliaga, Alicia; Monrabal-Capilla, María; Pinilla-Cienfuegos, Elena; Ceolin, Marcelo

2010-06-21

239

Using stormwater hysteresis to characterize karst spring discharge.  

PubMed

Discharge from karst springs contains a mixture of conduit and matrix water, but the variations in groundwater mixing are poorly known. Storm events present an opportunity to try to map flow components because water entering during storms is more dilute and provides a tracer as it mixes with pre-event water along the flowpath from the recharge area to discharge at a spring. We used hysteresis plots of Mg/Ca ratios in a spring in the Cumberland Valley of Pennsylvania to map conduit (higher Ca) vs. diffuse (higher Mg) sources of recharge. We observed two types of temporal heterogeneity: within a storm event and from storm to storm. The timing of the variation in Mg/Ca suggested sources of mixing waters. An increase in the Mg/Ca ratio at the beginning of some storms while conductivity declined suggested diffuse recharge through the epikarst. The rapid changes in Mg/Ca ratios for low-intensity events probably occurred as the rainfall waxed and waned and illustrate that a variety of flowpaths are available at this spring because additional flushing of Mg occurred. In contrast, the conductivity hysteresis began with dilute water initially and rotation was similar from storm to storm. Hysteresis plots of the Mg/Ca ratio have the potential of revealing more of the complexity in discharge than conductivity alone. A better understanding of flow components in karst is needed to protect these aquifers as a groundwater resource. PMID:22974348

Toran, Laura; Reisch, Chad E

2013-01-01

240

Hysteresis Behaviour and Specific Damping Capacity of Negative Poisson's Ratio Foams Martz, E. O., Lakes, R. S., and Park, J. B. "Hysteresis behaviour and specific damping capacity of  

E-print Network

1 Hysteresis Behaviour and Specific Damping Capacity of Negative Poisson's Ratio Foams Martz, E. O., Lakes, R. S., and Park, J. B. "Hysteresis behaviour and specific damping capacity of negative Poisson's ratio foams", Cellular Polymers, 15, 349-364, (1996). Abstract Open cell polyurethane foams have been

Lakes, Roderic

241

Neural networks based identification and compensation of rate-dependent hysteresis in piezoelectric actuators  

NASA Astrophysics Data System (ADS)

This paper presents a method of the identification for the rate-dependent hysteresis in the piezoelectric actuator (PEA) by use of neural networks. In this method, a special hysteretic operator is constructed from the Prandtl-Ishlinskii (PI) model to extract the changing tendency of the static hysteresis. Then, an expanded input space is constructed by introducing the proposed hysteretic operator to transform the multi-valued mapping of the hysteresis into a one-to-one mapping. Thus, a feedforward neural network is applied to the approximation of the rate-independent hysteresis on the constructed expanded input space. Moreover, in order to describe the rate-dependent performance of the hysteresis, a special hybrid model, which is constructed by a linear auto-regressive exogenous input (ARX) sub-model preceded with the previously obtained neural network based rate-independent hysteresis sub-model, is proposed. For the compensation of the effect of the hysteresis in PEA, the PID feedback controller with a feedforward hysteresis compensator is developed for the tracking control of the PEA. Thus, a corresponding inverse model based on the proposed modeling method is developed for the feedforward hysteresis compensator. Finally, both simulations and experimental results on piezoelectric actuator are presented to verify the effectiveness of the proposed approach for the rate-dependent hysteresis.

Zhang, Xinliang; Tan, Yonghong; Su, Miyong; Xie, Yangqiu

2010-06-01

242

Comparative experiments regarding approaches to feedforward hysteresis compensation for piezoceramic actuators  

NASA Astrophysics Data System (ADS)

Piezoceramic actuators (PCAs) are desired devices in many micro/nano-positioning applications. The performance of PCA-based applications is severely limited by the presence of hysteresis nonlinearity. To remedy the hysteresis nonlinearity in such systems, feedforward hysteresis compensation is the most common technique. In the literature, many different feedforward hysteresis compensation approaches have been developed, but there are no comparative studies of these approaches. Focusing on the modified Prandtl-Ishlinskii model (MPIM) for asymmetric hysteresis description of piezoceramic actuators, three feedforward hysteresis compensation approaches—inverse hysteresis compensation (IHC), without inverse hysteresis compensation (WIHC), and direct inverse hysteresis compensation (DIHC)—are developed and compared in this paper. Extensive comparative experiments were conducted on a PCA-actuated stage to verify the effectiveness of the three different feedforward control approaches to hysteresis compensation. The experimental results show that the performances among the three approaches are rather similar, and the main differences among them are due to the specific implementation of each approach.

Gu, Guo-Ying; Zhu, Li-Min

2014-09-01

243

Development of a Portable Mechanical Hysteresis Measurement and Imaging System for Impact Characterization in Honeycomb Sandwich Structures  

NASA Astrophysics Data System (ADS)

Honeycomb sandwich materials are commonly used for aero-structures, but because the outer skins are typically thin, 2-10 plys, the structures are susceptible to impact damage. NDI methods such as tap tests, bond testers and TTU ultrasound are successfully deployed to find impact damage, but identifying the type/degree of damage is troublesome. As the type/degree of impact damage guides decisions by the maintenance, repair and overhaul (MRO) community regarding repair, the ability to characterize impacts is of interest. Previous work demonstrated that additional impact characterization may be gleaned from hysteresis loop area, as determined from an out-of-plane load-vs-displacement plot, where this parameter shows a correlation with impact energy. This presentation reports on current work involving the development of a portable hysteresis measurement and imaging system based on an instrumented tapper. Data processing and analysis methods that allow production of the load/displacement data from a single accelerometer are discussed, with additional reporting of tests of software to automatically vary pixel size during scanning to decrease C-scans inspection time.

Barnard, Daniel J.; Hsu, David K.

2011-06-01

244

Development of a portable mechanical hysteresis measurement and imaging system for impact characterization in honeycomb sandwich structures  

SciTech Connect

Honeycomb sandwich materials are commonly used for aero-structures, but because the outer skins are typically thin, 2-10 plys, the structures are susceptible to impact damage. NDI methods such as tap tests, bond testers and TTU ultrasound are successfully deployed to find impact damage, but identifying the type/degree of damage is troublesome. As the type/degree of impact damage guides decisions by the maintenance, repair and overhaul (MRO) community regarding repair, the ability to characterize impacts is of interest. Previous work demonstrated that additional impact characterization may be gleaned from hysteresis loop area, as determined from an out-of-plane load-vs-displacement plot, where this parameter shows a correlation with impact energy. This presentation reports on current work involving the development of a portable hysteresis measurement and imaging system based on an instrumented tapper. Data processing and analysis methods that allow production of the load/displacement data from a single accelerometer are discussed, with additional reporting of tests of software to automatically vary pixel size during scanning to decrease C-scans inspection time.

Barnard, Daniel J.; Hsu, David K. [Center for NDE, Iowa State University, Ames, IA 50011 (United States)

2011-06-23

245

Cochlear hysteresis: observation with low-frequency modulated distortion product otoacoustic emissions.  

PubMed

Low-frequency modulation of distortion product otoacoustic emissions (DPOAEs) can be used to estimate a nonlinear transducer function (fTr) of the cochlea. From gerbils, DPOAEs were measured while presenting a high-level bias tone. Within one period of the bias tone, the magnitudes of the cubic difference tone (CDT, 2f1 - f2) demonstrated two similar modulation patterns (MPs) each resembled the absolute value of the third derivative of the fTr. The center peaks of the MPs occurred at positive sound pressures for rising in bias pressure or loading of the cochlear transducer, and more negative pressures while decreasing bias amplitude or unloading. The corresponding fTr revealed a sigmoid-shaped hysteresis loop with counterclockwise traversal. Physiologic indices that characterized the double MP varied with primary level. A Boltzmann-function-based model with negative damping as a feedback component was proposed. The model was able to replicate the experimental results. Model parameters that fit to the CDT data indicated higher transducer gain and more prominent feedback role at lower primary levels. Both physiologic indices and model parameters suggest that the cochlear transducer dynamically changes its gain with input signal level and the nonlinear mechanism is a time-dependent feedback process. PMID:15139627

Bian, Lin; Linhardt, Erin E; Chertoff, Mark E

2004-05-01

246

Hysteresis, avalanches, and disorder-induced critical scaling: A renormalization-group approach  

SciTech Connect

Hysteresis loops are often seen in experiments at first-order phase transformations, when the system goes out of equilibrium. They may have a macroscopic jump (roughly as in the supercooling of liquids) or they may be smoothly varying (as seen in most magnets). We have studied the nonequilibrium zero-temperature random-field Ising-model as a model for hysteretic behavior at first-order phase transformations. As disorder is added, one finds a transition where the jump in the magnetization (corresponding to an infinite avalanche) decreases to zero. At this transition we find a diverging length scale, power-law distributions of noise (avalanches), and universal behavior. We expand the critical exponents about mean-field theory in 6{minus}{epsilon} dimensions. Using a mapping to the pure Ising model, we Borel sum the 6{minus}{epsilon} expansion to {ital O}({epsilon}{sup 5}) for the correlation length exponent. We have developed a method for directly calculating avalanche distribution exponents, which we perform to {ital O}({epsilon}). Our analytical predictions agree with numerical exponents in two, three, four, and five dimensions [Perkovi{acute c} {ital et} {ital al}., Phys. Rev. Lett. {bold 75}, 4528 (1995)]. {copyright} {ital 1996 The American Physical Society.}

Dahmen, K.; Sethna, J.P. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (United States)] [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (United States)

1996-06-01

247

Fast flux locked loop  

DOEpatents

A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)

2002-09-10

248

The preprocessed doacross loop  

NASA Technical Reports Server (NTRS)

Dependencies between loop iterations cannot always be characterized during program compilation. Doacross loops typically make use of a-priori knowledge of inter-iteration dependencies to carry out required synchronizations. A type of doacross loop is proposed that allows the scheduling of iterations of a loop among processors without advance knowledge of inter-iteration dependencies. The method proposed for loop iterations requires that parallelizable preprocessing and postprocessing steps be carried out during program execution.

Saltz, Joel H.; Mirchandaney, Ravi

1990-01-01

249

RBF neural networks hysteresis modelling for piezoceramic actuator using hybrid model  

NASA Astrophysics Data System (ADS)

An radial basis function (RBF) neural networks rate-dependent hysteresis hybrid model for piezoceramic actuator is proposed. The piezoceramic actuator cannot be described by neural networks like the back propagation (BP) static neural networks because of its multi-valued hysteresis non-linearity. The proposed hybrid hysteresis model consists of hysteresis-like non-linearity in series with a dynamic RBF neural networks used for implementing non-linear transformations of the phase lag and non-linear magnitude. The hysteresis-like non-linearity model, which is composed of the previous output of piezoceramic actuator and input signal, differs from the hysteresis behaviour of piezoceramic actuator in only ways of their phase and magnitude, and it is used to describe the non-smooth behaviour of piezoceramic actuator. The results of both simulation and experiment show that the new modelling approach is very effective and of higher precision under a decayed input signal with the varying frequency.

Dang, Xuanju; Tan, Yonghong

2007-01-01

250

Origin of hysteresis in bed form response to unsteady flows  

NASA Astrophysics Data System (ADS)

Field and laboratory studies indicate that changes in riverbed morphology often lag changes in water discharge. This lagged response produces hysteresis in the relationship between water discharge and bed form geometry. To understand these phenomena, we performed flume experiments to observe the response of a sand bed to step increases and decreases in water discharge. For an abrupt rise in discharge, we observed that bed forms grew rapidly by collision and merger of bed forms migrating with different celerities. Growth rate slowed as bed forms approached equilibrium with the higher discharge regime. After an abrupt discharge drop, bed form decay occurred through formation of smaller secondary bed forms, in equilibrium with the lower discharge, which cannibalized the original, relict features. We present a simple model framework to quantitatively predict time scales of bed form adjustment to flow changes, based on equilibrium bed form heights, lengths, and celerities at low and high flows. For rising discharge, the model assumes that all bed form collisions result in irreversible merger, due to a dispersion of initial celerities. For falling discharge, we derive a diffusion model for the decay of relict high-stage features. Our models predict the form and time scale of experimental bed form adjustments. Additional experiments applying slow and fast triangular flood waves show that bed form hysteresis occurs only when the time scale of flow change is faster than the modeled (and measured) bed form adjustment time. We show that our predicted adjustment time scales can also be used to predict the occurrence of bed form hysteresis in natural floods.

Martin, Raleigh L.; Jerolmack, Douglas J.

2013-03-01

251

Effect of contact angle hysteresis on moving liquid film integrity  

NASA Technical Reports Server (NTRS)

A study was made of the formation and breakdown of a water film moving over solid surfaces (teflon, lucite, stainless steel, and copper). The flow rate associated with film formation was found to be higher than the flow rate at which film breakdown occurred. The difference in the flow rates for film formation and film breakdown was attributed to contact angle hysteresis. Analysis and experiment, which are in good agreement, indicated that film formation and film breakdown are functions of the advancing and receding angles, respectively.

Simon, F. F.; Hsu, Y. Y.

1972-01-01

252

Analysis of power magnetic components with nonlinear static hysteresis: finite-element formulation  

Microsoft Academic Search

We present a new systematic methodology to efficiently solve coupled electromagnetic problems with nonlinear hysteresis at low frequency (10 kHz), called static hysteresis, by the finite-element method. The methodology integrates a new domain-wall-motion hysteresis model for power magnetic components (POMACs) into a finite-element potential formulation via an implicit-inverse model calculation. It uses a novel two-level iterative algorithm incorporating the efficient

Y. Zhai; L. Vu-Quoc

2005-01-01

253

Element-specific magnetic hysteresis measurements, a new application of circularly polarized soft x-rays  

SciTech Connect

Element-specific magnetic hysteresis measurements on heteromagnetic materials have been achieved by using circularly polarized soft-x- rays. Dramatically different Fe and Co hysteresis curves of Fe/Cu/Co trilayers were obtained by recording the magnetic circular dichroism (MCD) at their respective L{sub 3} white lines as a function of applied magnetic field. The data resolve the complicated hysteresis curves, observed by conventional magnetometry, and determine the individual magnetic moments for the Fe and Co layers. Fine hysteresis features, imperceptible in the conventional curves, were also observed, demonstrating a new application of circularly polarized soft-x-rays in the investigation of magnetic systems.

Lin, H.J.; Chen, C.T.; Meigs, G. [AT and T Bell Labs., Murray Hill, NJ (United States); Idzerda, Y.U.; Chaiken, A.; Prinz, G.A. [Naval Research Lab., Washington, DC (United States); Ho, G.H. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Physics

1993-09-07

254

Hysteresis and saturation effects with the ALS lattice magnets  

SciTech Connect

The primary purpose of the magnetic measurements performed on the ALS storage ring lattice magnets was to ascertain their compliance with the strict tolerances established for this third-generation synchrotron light source. In the course of the data evaluation, an approximation method has been developed that leads to four-parameter representations of all magnet transfer functions. The expressions for the transfer functions were now used to change the standard working point of the ALS storage ring from the upper to the lower hysteresis branches of all lattice magnet families, and later to ramp the ring from the customary 1.5 GeV to the maximum design energy of 1.9 GeV in one uninterrupted process that did not require any intermediate tune correction. This achievement is all the more remarkable as no remnant fields had directly been measured with any of these magnets. A specific remnant field effect that led to anomalous machine behavior-when trying to recuperate the betatron tunes on the lower hysteresis branch at standard energy could be ascribed to the C-shape of the quadrupole yokes.

Keller, R.

1995-04-01

255

Fractal growth of liquid crystals as a hysteresis phenomenon  

NASA Astrophysics Data System (ADS)

Fractal percolation growth of liquid crystal phases within a supercooled isotropic liquid medium has been observed in recent years. Notable examples include the B2 phase of `banana' mesogens [1] and the smectic C phase of a calamitic hydrogen-bonding liquid crystal [2]. Here we present a dynamical model that describes such fractal growth as well as the spherical growth conventionally observed for nematics and cholesterics. The essential idea is that the supercooled medium does not fully respond to the temperature quench immediately (hysteresis). Its fraction of space available for the phase transition only relaxes from 0 to 1 at some finite rate. Depending on the coupling between the relaxation and growth rates, the liquid crystal phase either grows as a percolation cluster of fractal dimension D 1.89 or approaches a spherical shape of Euclidean dimension D -> 2. The crossover behaviour from relatively slow to fast relaxation is thoroughly investigated. Possible causes of the hysteresis for fractal growth will be discussed. [1] I. Dierking, Liq. Cryst. Today 12(1), (2003), 1 [2] I. Dierking, Chan H. K., Culfaz F., McQuire S., Phys. Rev. E 70, (2004), 051701

Chan, Ho-Kei; Dierking, Ingo

2006-03-01

256

Wavenumber selection and hysteresis in nonlinear baroclinic flow  

NASA Technical Reports Server (NTRS)

Wavenumber transition and hysteresis in a highly unstable baroclinic flow are investigated using a high-resolution spectral numerical model. As the flow becomes more supercritical, the dominant wave gradually shifts from the most unstable wave predicted by the linear theory to a longer wave with a larger time-averaged amplitude, while the rectified mean flow attains a stronger shear at the center of the channel. The numerical results display a complex hysteresis behavior, which occurs not only between the states of different dominant wavenumbers, but also between the states of identical dominant wavenumber but of different dynamic characteristics. In a certain parameter range three stable states, each with different dominant wavenumber, are possible, and in another parameter range four stable states are possible, among them three stable states with an identical dominant wave. The numerical results suggest that a multiple weather regime exists even without external forcing in which the flow aperiodically varies between two distinct behaviors. The effects of stable higher harmonics are assessed and it is found that their presence contributes not only to the better approximation of the model solutions but also to the selection of the final equilibrium state, due to the chaotic nature of the initial transient period.

Chou, Shih-Hung

1995-01-01

257

Climate Feedback Loops  

NSDL National Science Digital Library

This is the seventh of nine lessons in the 'Visualizing and Understanding the Science of Climate Change' website. This lesson addresses climate feedback loops and how these loops help drive and regulate Earth's unique climate system.

King's Centre for Visualization in Science Researchers

258

Transgressive loop group extensions  

E-print Network

A central extension of the loop group of a Lie group is called transgressive, if it corresponds under transgression to a degree four class in the cohomology of the classifying space of the Lie group. Transgressive loop group extensions are those that can be explored by finite-dimensional, higher-categorical geometry over the Lie group. We show how transgressive central extensions can be characterized in a loop-group theoretical way, in terms of loop fusion and thin homotopy equivariance.

Konrad Waldorf

2015-02-17

259

Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4  

NASA Astrophysics Data System (ADS)

We present a study of the model spin-glass LiHo0.5Er0.5F4 using simultaneous ac susceptibility, magnetization, and magnetocaloric effect measurements along with small angle neutron scattering (SANS) at sub-Kelvin temperatures. All measured bulk quantities reveal hysteretic behavior when the field is applied along the crystallographic c axis. Furthermore, avalanchelike relaxation is observed in a static field after ramping from the zero-field-cooled state up to 200-300 Oe. SANS measurements are employed to track the microscopic spin reconfiguration throughout both the hysteresis loop and the related relaxation. Comparing the SANS data to inhomogeneous mean-field calculations performed on a box of one million unit cells provides a real-space picture of the spin configuration. We discover that the avalanche is being driven by released Zeeman energy, which heats the sample and creates positive feedback, continuing the avalanche. The combination of SANS and mean-field simulations reveal that the conventional distribution of cluster sizes is replaced by one with a depletion of intermediate cluster sizes for much of the hysteresis loop.

Piatek, J. O.; Kovacevic, I.; Babkevich, P.; Dalla Piazza, B.; Neithardt, S.; Gavilano, J.; Krämer, K. W.; Rønnow, H. M.

2014-11-01

260

A compact single-pass architecture for hysteresis thresholding and component labeling  

Microsoft Academic Search

Hysteresis thresholding offers enhanced edge\\/object detection in the presence of noise. However, due to its recursive nature, it requires a lot of memory and execution time. Thus, it is restricted and sometimes totally avoided in streaming processors with limited memory. We propose an efficient architecture coupling hysteresis thresholding with component labeling and feature extraction in a single pass over the

Mayssaa Al Najjar; Swetha Karlapudi; Magdy A. Bayoumi

2010-01-01

261

A novel hysteresis current controller for multilevel single phase voltage source inverters  

Microsoft Academic Search

The application and benefits of hysteresis current control for two level voltage source inverters are well understood, but the extension of the strategy to multilevel inverters is much less established. Previous approaches have used either multiple hysteresis bands or a time based lockout strategy to decide when to switch to successive voltage levels, but these approaches are either complex, and\\/or

G. H. Bode; D. N. Zmood; P. C. Loh; D. G. Holmes

2001-01-01

262

Hysteresis compensation in PZT bimorph mirrors: Preisach's classical and non-linear models  

Microsoft Academic Search

A number of reflective wavefront correctors used in adaptive optics are based on the use of piezoelectric effect, either in piston, tip\\/tilt or curvature devices. The relation between the voltage applied to drive these devices and the mechanical response always presents hysteresis to some extent. In this work we study the performance of Preisach's classical and non-linear models of hysteresis

Alfredo Dubra; John S. Massa; Carl Paterson

2005-01-01

263

Onset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water dynamics  

E-print Network

Onset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water hysteresis in canopy conductance, hydraulic lift, and compensatory root water uptake during extended drying effective is dictated by soil hydraulic properties and surrogates for atmospheric water vapor demand

Katul, Gabriel

264

Continuum Damage Mechanics for hysteresis and fatigue of quasi-brittle materials and structures  

E-print Network

Continuum Damage Mechanics for hysteresis and fatigue of quasi-brittle materials and structures R in the present work that damage, from the Continuum Damage Mechanics point of view, may be seen as the link@lmt.ens-cachan.fr, tel: 33 1 47 40 74 60, fax: 33 1 47 40 74 65 #12;CONTINUUM DAMAGE MECHANICS FOR HYSTERESIS AND FATIGUE

265

Hysteresis from antiferromagnet domain-wall processes in exchange biased systems  

Microsoft Academic Search

The presence of magnetic impurities in the antiferromagnet can account for some ferromagnetic hysteresis behavior observed in exchange bias systems. We show theoretically that such impurities can modify domain-wall formation in the antiferromagnet, which under certain conditions can give rise to coercivity enhancement and asymmetric hysteresis. The linear dynamics of the ferromagnet\\/antiferromagnet structure in the presence of impurities is also

Joo-Von Kim; R. L. Stamps

2005-01-01

266

Hysteresis, Avalanches, and Noise Matthew C. Kuntz, Olga Perkovi'c, Karin A. Dahmen,  

E-print Network

Hysteresis, Avalanches, and Noise Matthew C. Kuntz, Olga Perkovi'c, Karin A. Dahmen, Bruce W simulations. In our studies of hysteresis and avalanches in a sim­ ple model of magnetism (the random be triggered when one of its neighbors flips (by participating in an avalanche), or a spin can be triggered

Sethna, James P.

267

cond-mat/9809122v223Apr1999 Hysteresis, Avalanches, and Noise  

E-print Network

cond-mat/9809122v223Apr1999 Hysteresis, Avalanches, and Noise Matthew C. Kuntz, Olga Perkovi becomes crucial for larger simulations. In our studies of hysteresis and avalanches in a sim- ple model participating in an avalanche), or a spin can be triggered because of an increase in the external field H

Sethna, James P.

268

Interval Maps with Hysteresis A thesis submitted to the University of Strathclyde  

E-print Network

Dynamics of Interval Maps with Hysteresis A thesis submitted to the University of Strathclyde of multistate maps, maps with hysteresis. The map under consideration is a collection of two continuous function is applied. We study two di#11;erent aspects of such maps: topological and combinato- rial

Berkolaiko, Gregory

269

A time-based double band hysteresis current regulation strategy for single-phase multilevel inverters  

Microsoft Academic Search

Most multilevel inverter hysteresis current regulators use either multiple hysteresis bands, or a time-based switching logic that forces the current error back to zero by recursively stepping through successive voltage levels. Of these two alternatives, the time-based approach has the merit of only requiring simple analog circuitry and digital logic to implement the voltage level selection process for inverters of

P. C. Loh; G. H. Bode; D. G. Holmes; T.A. Lipo

2002-01-01

270

Hysteresis in the metachronal-tripod gait transition of insects: A modeling study  

NASA Astrophysics Data System (ADS)

Locomotion in biological systems involves various gaits, and hysteresis appears when the gaits change in accordance with the locomotion speed. That is, the gaits vary at different locomotion speeds depending on the direction of speed change. Although hysteresis is a typical characteristic of nonlinear dynamic systems, the underlying mechanism for the hysteresis in gait transitions remains largely unclear. In this study, we construct a neuromechanical model of an insect and investigate the dynamic characteristics of its gait and gait transition. The simulation results show that our insect model produces metachronal and tripod gaits depending on the locomotion speed through dynamic interactions among the body mechanical system, the nervous system, and the environment in a self-organized manner. They also show that it undergoes the metachronal-tripod gait transition with hysteresis by changing the locomotion speed. We examined the hysteresis mechanism in the metachronal-tripod gait transition of insects from a dynamic viewpoint.

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2013-07-01

271

Note: Simple hysteresis parameter inspector for camera module with liquid lens.  

PubMed

A method to inspect hysteresis parameter is presented in this article. The hysteresis of whole camera module with liquid lens can be measured rather than a single lens merely. Because the variation in focal length influences image quality, we propose utilizing the sharpness of images which is captured from camera module for hysteresis evaluation. Experiments reveal that the profile of sharpness hysteresis corresponds to the characteristic of contact angle of liquid lens. Therefore, it can infer that the hysteresis of camera module is induced by the contact angle of liquid lens. An inspection process takes only 20 s to complete. Thus comparing with other instruments, this inspection method is more suitable to integrate into the mass production lines for online quality assurance. PMID:20515182

Chen, Po-Jui; Liao, Tai-Shan; Hwang, Chi-Hung

2010-05-01

272

Hysteresis in coral reefs under macroalgal toxicity and overfishing.  

PubMed

Macroalgae and corals compete for the available space in coral reef ecosystems.While herbivorous reef fish play a beneficial role in decreasing the growth of macroalgae, macroalgal toxicity and overfishing of herbivores leads to proliferation of macroalgae. The abundance of macroalgae changes the community structure towards a macroalgae-dominated reef ecosystem. We investigate coral-macroalgal phase shifts by means of a continuous time model in a food chain. Conditions for local asymptotic stability of steady states are derived. It is observed that in the presence of macroalgal toxicity and overfishing, the system exhibits hysteresis through saddle-node bifurcation and transcritical bifurcation. We examine the effects of time lags in the liberation of toxins by macroalgae and the recovery of algal turf in response to grazing of herbivores on macroalgae by performing equilibrium and stability analyses of delay-differential forms of the ODE model. Computer simulations have been carried out to illustrate the different analytical results. PMID:25708511

Bhattacharyya, Joydeb; Pal, Samares

2015-03-01

273

Hysteresis in multiphase microfluidics at a T-junction.  

PubMed

Multiphase microfluidics offer a wide range of functionalities in the fields of fluid dynamics, biology, particle synthesis, and, more recently, also in logical computation. In this article, we describe the hysteresis of immiscible, multiphase flow obtained in hydrophilic, microfluidic systems at a T-junction. Stable and unstable state behaviors, in the form of segmented and parallel flow patterns of oil and water, were reliably produced, depending upon the history of the flow rates applied to the phases. The transition mechanisms between the two states were analyzed both experimentally and using numerical simulations, describing how the physical and fluid dynamic parameters influenced the hysteretic behavior of the flow. The characteristics of these multiphase systems render them suitable to be used as pressure comparators and also for the implementation of microfluidic logic operations. PMID:20465264

Zagnoni, Michele; Anderson, Jamie; Cooper, Jonathan M

2010-06-15

274

Wafer-level hysteresis-free resonant carbon nanotube transistors.  

PubMed

We report wafer-level fabrication of resonant-body carbon nanotube (CNT) field-effect transistors (FETs) in a dual-gate configuration. An integration density of >10(6) CNTFETs/cm(2), an assembly yield of >80%, and nanoprecision have been simultaneously obtained. Through combined chemical and thermal treatments, hysteresis-free (in vacuum) suspended-body CNTFETs have been demonstrated. Electrostatic actuation by lateral gate and FET-based readout of mechanical resonance have been achieved at room temperature. Both upward and downward in situ frequency tuning has been experimentally demonstrated in the dual-gate architecture. The minuscule mass, high resonance frequency, and in situ tunability of the resonant CNTFETs offer promising features for applications in radio frequency signal processing and ultrasensitive sensing. PMID:25752991

Cao, Ji; Bartsch, Sebastian T; Ionescu, Adrian M

2015-03-24

275

The thermodynamic origin of hysteresis in insertion batteries  

NASA Astrophysics Data System (ADS)

Lithium batteries are considered the key storage devices for most emerging green technologies such as wind and solar technologies or hybrid and plug-in electric vehicles. Despite the tremendous recent advances in battery research, surprisingly, several fundamental issues of increasing practical importance have not been adequately tackled. One such issue concerns the energy efficiency. Generally, charging of 1010-1017 electrode particles constituting a modern battery electrode proceeds at (much) higher voltages than discharging. Most importantly, the hysteresis between the charge and discharge voltage seems not to disappear as the charging/discharging current vanishes. Herein we present, for the first time, a general explanation of the occurrence of inherent hysteretic behaviour in insertion storage systems containing multiple particles. In a broader sense, the model also predicts the existence of apparent equilibria in battery electrodes, the sequential particle-by-particle charging/discharging mechanism and the disappearance of two-phase behaviour at special experimental conditions.

Dreyer, Wolfgang; Jamnik, Janko; Guhlke, Clemens; Huth, Robert; Moškon, Jože; Gaberš?ek, Miran

2010-05-01

276

Hysteresis in Magnetic Shape Memory Composites: Modeling and Simulation  

E-print Network

Magnetic shape memory alloys are characterized by the coupling between a structural phase transition and magnetic one. This permits to control the shape change via an external magnetic field, at least in single crystals. Composite materials with single-crystalline particles embedded in a softer matrix have been proposed as a way to overcome the blocking of the transformation at grain boundaries. We investigate hysteresis phenomena for small NiMnGa single crystals embedded in a polymer matrix for slowly varying magnetic fields. The evolution of the microstructure is studied within the rate-independent variational framework proposed by Mielke and Theil (1999). The underlying variational model incorporates linearized elasticity, micromagnetism, stray field and a dissipation term proportional to the volume swept by the phase boundary. The time discretization is based on an incremental minimization of the sum of energy and dissipation. A backtracking approach is employed to approximately ensure the global minimali...

Conti, Sergio; Rumpf, Martin

2015-01-01

277

Phase transition and hysteresis in scale-free network traffic  

E-print Network

We model information traffic on scale-free networks by introducing the node queue length L proportional to the node degree and its delivering ability C proportional to L. The simulation gives the overall capacity of the traffic system which is quantified by a phase transition from free flow to congestion. It is found that the maximal capacity of the system results from the case of the local routing coefficient \\phi slightly larger than zero, and we provide an analysis for the optimal value of \\phi. In addition, we report for the first time the fundamental diagram of flow against density, in which hysteresis is found, and thus we can classify the traffic flow with four states: free flow, saturated flow, bistable and jammed.

Hu, M B; Wang, W X; Wu, Q S; Wu, Y H; Hu, Mao-Bin; Jiang, Rui; Wang, Wen-Xu; Wu, Qing-Song; Wu, Yong-Hong

2006-01-01

278

Loop functions in thermal QCD  

E-print Network

We discuss divergences of loop functions in thermal QCD and compute perturbatively the Polyakov loop, the Polyakov loop correlator and the cyclic Wilson loop. We show how these functions get mixed under renormalization.

Antonio Vairo

2014-10-16

279

The extrinsic hysteresis behavior of dilute binary ferrofluids.  

PubMed

We report on the magnetization behavior of dilute binary ferrofluids based on ?-Fe(2)O(3)/Ni(2)O(3) composite nanoparticles (A particles), with diameter about 11 nm, and ferrihydrite (Fe(5)O(7)(OH) ?4H2O) nanoparticles (B particles), with diameter about 6 nm. The results show that for the binary ferrofluids with A-particle volume fraction ?(A) = 0.2% and B-particle volume fractions ?(B) = 0.1% and ?(B) = 0.6%, the magnetization curves exhibit quasi-magnetic hysteresis behavior. The demagnetizing curves coincide with the magnetizing curves at high fields. However, for single ?-Fe(2)O(3)/Ni(2)O(3) ferrofluids with ?(A) = 0.2% and binary ferrofluids with ?(A) = 0.2% and ?(B) = 1.0%, the magnetization curves do not behave in this way. Additionally, at high field (750 kA/m), the binary ferrofluid with ?(B) = 1.0% has the smallest magnetization. From the model-of-chain theory, the extrinsic hysteresis behavior of these samples is attributed to the field-induced effects of pre-existing A particle chains, which involve both Brownian rotation of the chains'moments and a Néel rotation of the particles' moments in the chains. The loss of magnetization for the ferrofluids with ?(B) = 1.0% is attributed to pre-existing ring-like A-particle aggregates. These magnetization behaviors of the dilute binary ferrofluids not only depend on features of the strongly magnetic A-particle system, but also modifications of the weaker magnetic B-particle system. PMID:25365919

Lin, Lihua; Li, Jian; Lin, Yueqiang; Liu, Xiaodong; Chen, Longlong; Li, Junming; Li, Decai

2014-10-01

280

Magnetization loop modelling for superconducting/ferromagnetic tube of an ac magnetic cloak  

NASA Astrophysics Data System (ADS)

From the combination of superconducting (SC) and ferromagnetic (FM) materials, one can prepare composites with unusual magnetic properties, e.g. for the cloaking of a dc or low-frequency ac magnetic field by a shell from a SC/FM composite. In the design and optimisation of such SC/FM structures, numerical modelling is essential. Non-linear magnetic permeability, as well as the hysteresis of both kinds of materials, are to be incorporated in the calculations aimed at achieving reliable estimates. We present a technique that allows the prediction of the ac magnetization loops of SC/FM composites. The critical state model-based approach is used to describe the properties of the superconducting material. The ferromagnetic part is characterized by its (non-hysteretic) nonlinear permeability. With these ingredients, the distributions of the magnetic field are calculated in subsequent instants of the ac cycle and are used to evaluate the preliminary data for the magnetization loop, which is still missing the hysteresis of the FM part. Afterward, the latter component is added to the magnetization loop by an approximation deduced from the known dependence of the hysteresis loss in the FM material on the ac magnetic field. In spite of its approximate nature, this approach demonstrated very good predictability in experimental tests.

Gömöry, F.; Solovyov, M.; Šouc, J.

2015-04-01

281

March 23, 2008 ICS102: For Loop 1 The for-loop and Nested loops  

E-print Network

March 23, 2008 ICS102: For Loop 1 The for-loop and Nested loops #12;March 23, 2008 ICS102: For Loop, and exit Statements #12;March 23, 2008 ICS102: For Loop 3 - The for Statement Syntax for (Initializing;March 23, 2008 ICS102: For Loop 4 - The for Statement The for statement is most commonly used to step

Adam, Salah

282

BIOGRAPHICAL DATA OF EUGENE JOSEPH LEBOEUF, PH.D., P.E.  

E-print Network

BIOGRAPHICAL DATA OF EUGENE JOSEPH LEBOEUF, PH.D., P.E. 25 August 2010 CURRENT POSITION: Associate Station B 351831 Nashville, TN 37235 (615) 343-7070 eugene.j.leboeuf@vanderbilt.edu AREAS OF CONCENTRATION-Command Course, 2009 U.S. Army War College, 2010 #12;Biographical Data Eugene J. LeBoeuf, Ph.D., P.E. 2

Simaan, Nabil

283

Use of Vaccines in Finfish Aquaculture1 Roy P. E. Yanong2  

E-print Network

FA156 Use of Vaccines in Finfish Aquaculture1 Roy P. E. Yanong2 1. This document is FA156, one://edis.ifas.ufl.edu. 2. Roy P.E. Yanong, associate professor and extension veterinarian, Tropical Aquaculture Laboratory in aquaculture. Optimal husbandry and general management--including biosecurity, nutrition, genetics, system

Watson, Craig A.

284

Loop-weighted Walk  

E-print Network

Loop-weighted walk with parameter $\\lambda\\geq 0$ is a non-Markovian model of random walks that is related to the loop $O(N)$ model of statistical mechanics. A walk receives weight $\\lambda^{k}$ if it contains $k$ loops; whether this is a reward or punishment for containing loops depends on the value of $\\lambda$. A challenging feature of loop-weighted walk is that it is not purely repulsive, meaning the weight of the future of a walk may either increase or decrease if the past is forgotten. Repulsion is typically an essential property for lace expansion arguments. This article circumvents the lack of repulsion and proves, via the lace expansion, that for any $\\lambda\\geq 0$ loop-weighted walk is diffusive in high dimensions.

Tyler Helmuth

2014-10-12

285

Resonances of coronal loops  

NASA Technical Reports Server (NTRS)

It is pointed out that any theoretical demonstration that the solar corona can be heated by waves requires a demonstration that the required energies can actually be carried from the convection zone to the corona by waves. In addition, it must be shown that the waves can dissipate their energy into heat in the corona. The present investigation is concerned specifically with the heating of closed magnetic structures in the corona, taking into account coronal loops or active region loops. Attention is given to the MHD Alfven wave. It is shown analytically that coronal active region loops can behave much like interference filters. The coronal part of the loop acts like a resonant cavity for Alfven waves. When the resonances are excited, large energy fluxes can be carried into the loop by Alfven waves which are generated in the solar convection zone. It is estimated that the energy fluxes can power the observed loops.

Hollweg, J. V.

1984-01-01

286

Molecular thermal hysteresis in helix-dimer formation of sulfonamidohelicene oligomers in solution.  

PubMed

Sulfonamidohelicene oligomers up to the nonamer level were synthesized by the repeated coupling reactions of a building block. A tetramer formed a helix dimer in 1,3-difluorobenzene, which unfolded to a random coil with heating. This structural change exhibited thermal hysteresis in which different thermal responses were observed in the course of temperature increase and decrease. The feature of the hysteresis was examined under different heating/cooling modes, and the mechanisms are discussed on the basis of the population change and the presence of an induction period. A proposal regarding the use of thermal hysteresis for sensing a temperature increase/decrease is also given. PMID:23775763

Shigeno, Masanori; Kushida, Yo; Yamaguchi, Masahiko

2013-07-29

287

Effects of annealing, pre-tension and mounting on the hysteresis of polymer strain sensors  

NASA Astrophysics Data System (ADS)

When exposed to high levels of strain, polymer optical fibre grating sensors recorded in poly(methyl methacrylate) based fibre often exhibit hysteresis in the response of their Bragg wavelength to strain. We demonstrate that the application of pre-tension and annealing of the polymer fibre can reduce this hysteresis when the fibre is suspended freely between two supports, but much better performance is obtained when the sensor is attached directly to a substrate. In this case, the hysteresis can be lessened by more than a factor of 12.

Abang, Ada; Webb, David J.

2014-01-01

288

Implementation and analysis of an innovative digital charge amplifier for hysteresis reduction in piezoelectric stack actuators  

SciTech Connect

Smart actuators are the key components in a variety of nanopositioning applications, such as scanning probe microscopes and atomic force microscopes. Piezoelectric actuators are the most common smart actuators due to their high resolution, low power consumption, and wide operating frequency but they suffer hysteresis which affects linearity. In this paper, an innovative digital charge amplifier is presented to reduce hysteresis in piezoelectric stack actuators. Compared to traditional analog charge drives, experimental results show that the piezoelectric stack actuator driven by the digital charge amplifier has less hysteresis. It is also shown that the voltage drop of the digital charge amplifier is significantly less than the voltage drop of conventional analog charge amplifiers.

Bazghaleh, Mohsen, E-mail: mohsen.bazghaleh@adelaide.edu.au; Grainger, Steven; Cazzolato, Ben; Lu, Tien-Fu [School of Mechanical Engineering, The University of Adelaide, North Terrace, South Australia 5005 (Australia)] [School of Mechanical Engineering, The University of Adelaide, North Terrace, South Australia 5005 (Australia); Oskouei, Reza [School of Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia 5042 (Australia)] [School of Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia 5042 (Australia)

2014-04-15

289

Hysteresis of thin film IPRTs in the range 100 °C to 600 °C  

NASA Astrophysics Data System (ADS)

As opposed to SPRTs, the IPRTs succumb to hysteresis when submitted to change of temperature. This uncertainty component, although acknowledged as omnipresent at many other types of sensors (pressure, electrical, magnetic, humidity, etc.) has often been disregarded in their calibration certificates' uncertainty budgets in the past, its determination being costly, time-consuming and not appreciated by customers and manufacturers. In general, hysteresis is a phenomenon that results in a difference in an item's behavior when approached from a different path. Thermal hysteresis results in a difference in resistance at a given temperature based on the thermal history to which the PRTs were exposed. The most prominent factor that contributes to the hysteresis error in an IPRT is a strain within the sensing element caused by the thermal expansion and contraction. The strains that cause hysteresis error are closely related to the strains that cause repeatability error. Therefore, it is typical that PRTs that exhibit small hysteresis also exhibit small repeatability error, and PRTs that exhibit large hysteresis have poor repeatability. Aim of this paper is to provide hysteresis characterization of a batch of IPRTs using the same type of thin-film sensor, encapsulated by same procedure and same company and to estimate to what extent the thermal hysteresis obtained by testing one single thermometer (or few thermometers) can serve as representative of other thermometers of the same type and manufacturer. This investigation should also indicate the range of hysteresis departure between IPRTs of the same type. Hysteresis was determined by cycling IPRTs temperature from 100 °C through intermediate points up to 600 °C and subsequently back to 100 °C. Within that range several typical sub-ranges are investigated: 100 °C to 400 °C, 100 °C to 500 °C, 100 °C to 600 °C, 300 °C to 500 °C and 300 °C to 600 °C . The hysteresis was determined at various temperatures by comparison calibration with SPRT. The results of investigation are presented in a graphical form for all IPRTs, ranges and calibration points.

Zvizdi?, D.; Šestan, D.

2013-09-01

290

Feedback/feedforward control of hysteresis-compensated piezoelectric actuators for high-speed scanning applications  

NASA Astrophysics Data System (ADS)

This paper presents the control system design for a piezoelectric actuator (PEA) for a high-speed trajectory scanning application. First nonlinear hysteresis is compensated for by using the Maxwell resistive capacitor model. Then the linear dynamics of the hysteresis-compensated piezoelectric actuator are identified. A proportional plus integral (PI) controller is designed based on the linear system, enhanced by feedforward hysteresis compensation. It is found that the feedback controller does not always improve tracking accuracy. When the input frequency exceeds a certain value, feedforward control only may result in better control performance. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich

2015-01-01

291

Experimental investigations of boiling heat transfer hysteresis on sintered, metal - Fibrous, porous structures  

SciTech Connect

The paper discusses the results of experimental investigations of boiling heat transfer on sintered metal capillary-porous coverings of the heating surface. The experiments were carried out for copper, fibrous structures with stochastic distribution of pores. The boiling curves were obtained at the increasing and decreasing of the heat flux, which made it possible to detect the hysteresis phenomena of different types. The classification of the hysteresis phenomena, based on the author's own results and those available in the literature, was provided. Three types of hysteresis were observed. The physical mechanism of the phenomenon was presented and the features characteristic of boiling in the porous covering were taken into account. (author)

Wojcik, Tadeusz Michal [Department of Heat Engineering, Kielce University of Technology, Al. Tysiaclecia P.P.7, 25-314 Kielce (Poland)

2009-03-15

292

Loop Quantum Gravity  

Microsoft Academic Search

The problem of finding the quantum theory of the gravitational field, and\\u000athus understanding what is quantum spacetime, is still open. One of the most\\u000aactive of the current approaches is loop quantum gravity. Loop quantum gravity\\u000ais a mathematically well-defined, non-perturbative and background independent\\u000aquantization of general relativity, with its conventional matter couplings. The\\u000aresearch in loop quantum gravity

Carlo Rovelli

1997-01-01

293

Hysteresis Affects Approximate Number Discrimination in Young Children  

PubMed Central

Perceptual decisions are often affected not only by the evidence gathered during a trial but also by the history of preceding trials. This effect—termed perceptual hysteresis—provides evidence for how perceptual information is represented and how it is used. The present research focuses on how the difficulty of preceding trials affects subsequent ones—we find that how well 5-year-old children perform in a 2-alternative forced-choice numerical discrimination task depends on whether they have had a prior history of easier discriminations or a prior history of harder discriminations. Furthermore, this effect is modulated by the feedback children receive. In 3 experiments, we demonstrate that these effects are not related to practice or loss of interest due to negative feedback, or simply to trial difficulty or discriminability. Instead, children appear to have state-dependent confidence states such that prolonged experience making low-confidence decisions degrades performance, whereas prolonged experience making high-confidence decisions improves it. These results are discussed in the context of dynamical psychophysics, representations of confidence, and work on children’s and adults’ number perception abilities. PMID:23163765

Odic, Darko; Hock, Howard; Halberda, Justin

2015-01-01

294

Hysteresis and anisotropy in ultrathin Fe/Si(001) films  

NASA Astrophysics Data System (ADS)

It is challenging to investigate the magnetic anisotropy of Fe/Si(001) film in the case a limited magnetic field strength, when both coherent rotation and domain wall displacement coexist in the magnetization reversal process. Owing to the domain wall displacement, the magnetization reversal switching field is far lower than the magnetic anisotropy field, and, consequently, only the magnetization reversal process near easy axis can be treated as coherent rotation. Here, we record the slope of the magnetic torque curve of an iron film grown on a Si(001) substrate measured near the easy axis by anisotropic magnetoresistance (AMR) to separate the coherent rotation of magnetization reversal process from domain wall displacement. Furthermore, the magnitudes of various magnetic anisotropy constants were derived from the magnetic torque curves. Our work suggests that the AMR at low fields can clearly separate the detailed contributions of various magnetic anisotropies when domain wall displacement existed in Fe(001) ultrathin film. We also report on the hysteresis behavior of such films as measured by magneto-optic Kerr effect.

Ye, Jun; He, Wei; Wu, Qiong; Hu, Bo; Tang, Jin; Zhang, Xiang-Qun; Chen, Zi-Yu; Cheng, Zhao-Hua

2014-09-01

295

Solute concentration-dependent contact angle hysteresis and evaporation stains.  

PubMed

The presence of nonvolatile solutes in a liquid drop on a solid surface can affect the wetting properties. Depending on the surface-activity of the solutes, the extent of contact angle hysteresis (CAH) can vary with their concentration and the pattern of the evaporation stain is altered accordingly. In this work, four types of concentration-dependent CAH and evaporation stains are identified for a water drop containing polymeric additives on polycarbonate. For polymers without surface-activity such as dextran, advancing and receding contact angles (?a and ?r) are independent of solute concentrations, and a concentrated stain is observed in the vicinity of the drop center after complete evaporation. For polymers with weak surface-activity such as poly(ethylene glycol) (PEG), both ?a and ?r are decreased by solute addition, and the stain pattern varies with increasing PEG concentration, including a concentrated stain and a mountain-like island. For polymers with intermediate surface-activity such as sodium polystyrenesulfonate (NaPSS), ?a descends slightly, but ?r decreases significantly after the addition of a substantial amount of NaPSS, and a ring-like stain pattern is observed. Moreover, the size of the ring stain can be controlled by NaPSS concentration. For polymers with strong surface-activity such as poly(vinylpyrrolidone) (PVP), ?a remains essentially a constant, but ?r is significantly lowered after the addition of a small amount of PVP, and the typical ring-like stain is seen. PMID:24933206

Li, Yueh-Feng; Sheng, Yu-Jane; Tsao, Heng-Kwong

2014-07-01

296

Magnetic hysteresis of cerium doped bismuth ferrite thin films  

NASA Astrophysics Data System (ADS)

The influence of Cerium doping on the structural and magnetic properties of BiFeO3 thin films have been investigated. Rietveld refinement of X-ray diffraction data and successive de-convolution of Raman scattering spectra of Bi1-xCexFeO3 (BCFO) thin films with x=0-0.20 reflect the single phase rhombohedral (R3c) formation for x<0.08, whereas concentration-driven gradual structural phase transition from rhombohedral (R3c) to partial tetragonal (P4mm) phase follows for x?0.08. All low wavenumber Raman modes (<300 cm-1) showed a noticeable shift towards higher wavenumber with increase in doping concentration, except Raman E-1 mode (71 cm-1), shows a minor shift. Sudden evolution of Raman mode at 668 cm-1, manifested as A1-tetragonal mode, accompanied by the shift to higher wavenumber with increase in doping concentration (x) affirm partial structural phase transition. Anomalous wasp waist shaped (M-H) hysteresis curves with improved saturation magnetization (Ms) for BCFO thin films is attributed to antiferromagnetic interaction/hybridization between Ce 4f and Fe 3d electronic states. The contribution of both hard and soft phase to the total coercivity is calculated. Polycrystalline Bi0.88Ce0.12FeO3 thin film found to exhibit better magnetic properties with Ms=15.9 emu/g without any impure phase.

Gupta, Surbhi; Tomar, Monika; Gupta, Vinay

2015-03-01

297

The Dynamic Characteristic and Hysteresis Effect of an Air Spring  

NASA Astrophysics Data System (ADS)

In many applications of vibration technology, especially in chassis, air springs present a common alternative to steel spring concepts. A design-independent and therefore universal approach is presented to describe the dynamic characteristic of such springs. Differential and constitutive equations based on energy balances of the enclosed volume and the mountings are given to describe the nonlinear and dynamic characteristics. Therefore all parameters can be estimated directly from physical and geometrical properties, without parameter fitting. The numerically solved equations fit very well to measurements of a passenger car air spring. In a second step a simplification of this model leads to a pure mechanical equation. While in principle the same parameters are used, just an empirical correction of the effective heat transfer coefficient is needed to handle some simplification on this topic. Finally, a linearization of this equation leads to an analogous mechanical model that can be assembled from two common spring- and one dashpot elements in a specific arrangement. This transfer into "mechanical language" enables a system description with a simple force-displacement law and a consideration of the nonobvious hysteresis and stiffness increase of an air spring from a mechanical point of view.

Löcken, F.; Welsch, M.

2015-02-01

298

IEEE Transactions on Automation Science and Engineering Compensation of Scanner Creep and Hysteresis  

E-print Network

IEEE Transactions on Automation Science and Engineering Compensation of Scanner Creep uncertainties associated with creep and hysteresis, and supports automated, computer-controlled manipulation) and by automation, which bypasses the time- consuming

Southern California, University of

299

Magnetic structure and hysteresis in hard magnetic nanocrystalline film: Computer simulation  

E-print Network

Magnetic structure and hysteresis in hard magnetic nanocrystalline film: Computer simulation simulations are used to study the effect of crystallographic textures on the magnetic properties of uniaxial nanocrystalline films of hard magnetic materials with arbitrary grain shapes and size distributions

Laughlin, David E.

300

Abstract --In electromagnetic applications, hysteresis phenomena in magnetic materials are responsible of  

E-print Network

13. M M Abstract -- In electromagnetic applications, hysteresis phenomena in magnetic materials, electrical engineering is concerned with energy efficiency. In addition, in the case of electromagnetic.. Following the predefined criteria such as induction response and losses computation, some compatible models

Boyer, Edmond

301

Gravitons and loops  

Microsoft Academic Search

The recently proposed loop representation is used to quantize linearized general relativity. The Fock space of graviton states and its associated algebra of observables are represented in terms of functionals of loops. The ``reality conditions'' are realized by an inner product that is chiral asymmetric, resulting in a chiral-asymmetric ordering for the Hamiltonian, and, in an asymmetric description of the

Abhay Ashtekar; Carlo Rovelli; Lee Smolin

1991-01-01

302

What Controls DNA Looping?  

PubMed Central

The looping of DNA provides a means of communication between sequentially distant genomic sites that operate in tandem to express, copy, and repair the information encoded in the DNA base sequence. The short loops implicated in the expression of bacterial genes suggest that molecular factors other than the naturally stiff double helix are involved in bringing the interacting sites into close spatial proximity. New computational techniques that take direct account of the three-dimensional structures and fluctuations of protein and DNA allow us to examine the likely means of enhancing such communication. Here, we describe the application of these approaches to the looping of a 92 base-pair DNA segment between the headpieces of the tetrameric Escherichia coli Lac repressor protein. The distortions of the double helix induced by a second protein—the nonspecific nucleoid protein HU—increase the computed likelihood of looping by several orders of magnitude over that of DNA alone. Large-scale deformations of the repressor, sequence-dependent features in the DNA loop, and deformability of the DNA operators also enhance looping, although to lesser degrees. The correspondence between the predicted looping propensities and the ease of looping derived from gene-expression and single-molecule measurements lends credence to the derived structural picture. PMID:25167135

Perez, Pamela J.; Clauvelin, Nicolas; Grosner, Michael A.; Colasanti, Andrew V.; Olson, Wilma K.

2014-01-01

303

A novel double hysteresis-band current control for a three-level voltage source inverter  

Microsoft Academic Search

This paper presents a new current control strategy for a high power three-level voltage source inverter (VSI). This control strategy consists on an extension to a three-level topology of the well-known hysteresis-band current control for a conventional two-level VSI. Line current is controlled by means of two hysteresis bands slightly displaced around the reference value. A simple calculation block decides

M. Lafoz; I. J. Iglesias; C. Veganzones; M. Visiers

2000-01-01

304

Intercrystalline magnetic interaction and hysteresis characteristics of high-coercivity cobalt-based alloy coatings  

Microsoft Academic Search

?M(H) curves and the time dependences of the magnetization and the rotational hysteresis losses are used to analyze the effect\\u000a of intercrystalline magnetic interaction on the magnetization reversal and the hysteresis characteristics of nanostructured\\u000a cobalt-based alloy coatings, which manifest themselves in a change in the relations between the rotation and displacement\\u000a of reversible and irreversible processes and between thermally activated

V. G. Shadrov; A. E. Dmitrieva; L. V. Nemtsevich

2011-01-01

305

Three-Phase Four-Leg Inverter Based on Voltage Hysteresis Control  

Microsoft Academic Search

As the output unit of variety distributed generation systems, the final power quality is determined by three-phase four-leg inverter. For the three-phase four-leg inverter, this paper presents a dynamic reference voltage hysteresis control scheme. Firstly, based on the existing hysteresis comparison method, this method improves the systems control rapidity and stability through designing differential negative feedback. Secondly, through theoretical analysis

Xiaoyong Zhang; Jun Wang; Chuan Li

2010-01-01

306

Ac magnetorestriction hysteresis and magnetization direction in grain oriented silicon steels  

SciTech Connect

A hysteresis curve of ac magnetostriction was measured, magnetizing a grain oriented silicon steel in the direction deviated from rolling direction of a sample. The ac magnetostriction ({lambda} ac) curves were analyzed as harmonics in the interest of noise spectrum of such as a power transformer. The domain structure model in this magnetostriction process was proposed. The hysteresis was large in the magnetization direction inclined at 30 and 90{degree} from the rolling direction.

Mogi, Hisashi; Matsuo, Yukio; Kumano, Tomoji

1999-09-01

307

Dynamic interface charge governing the current-voltage hysteresis in perovskite solar cells.  

PubMed

The accumulation of mobile ions causes space charge at interfaces in perovskite solar cells. There is a slow dynamic process of ion redistribution when the bias is changed. The interface charge affects band bending and thus the photocurrent of the solar cells. Consequently the dynamic process of the interface charge governs the current-voltage hysteresis. Very low interface charge density leads to hysteresis-free devices. PMID:25772648

Zhang, Huimin; Liang, Chunjun; Zhao, Yong; Sun, Mengjie; Liu, Hong; Liang, Jingjing; Li, Dan; Zhang, Fujun; He, Zhiqun

2015-04-01

308

Measurements of the hysteresis in unzipping and rezipping double-stranded DNA  

NASA Astrophysics Data System (ADS)

Complete unzipping and rezipping of ? -phage double-stranded DNA is achieved by applying a constant force. A strong hysteresis is observed at all tested time scales and temperatures. Hysteresis also occurs for partial unzipping, indicating stability for the partially open state over a force range of 2- 5pN . Results are compared to nearest-neighbor model simulations, and reasonable agreement is found.

Hatch, K.; Danilowicz, C.; Coljee, V.; Prentiss, M.

2007-05-01

309

Hysteresis vs. Graded Responses: The Connections Make All the Difference  

NSDL National Science Digital Library

Biological regulatory systems have the potential to provide graded responses to stimuli or may demonstrate switch-like properties. Our understanding of the system design principles controlling these responses is still at a rudimentary stage, and here we consider several recent experimental and theoretical studies that focus on these system design principles. Overt positive feedback loops, or double-negative feedback loops, can produce bistable or multistable systems under the appropriate conditions and can produce graded responses under other conditions. Several design features favor bistability in negatively controlled genetic systems, including a high kinetic order for repression and a large difference in the rates of gene expression in the "on" and "off" states. In positive feedback, a high kinetic order for the activation of gene expression favors bistability. Multistability can result from the combined effects of positive and negative regulators, or from the combined effects of regulators that each demonstrate bistability. Finally, bistability can result in enzymatic systems in which multiple reversible covalent modifications occur, even when no overt feedback loops are present.

Alexander J. Ninfa (Ann Arbor; University of Michigan Medical School REV)

2004-05-11

310

Hysteresis Effects and Strain-Induced Homogeneity Effects in Base Metal Thermocouples  

NASA Astrophysics Data System (ADS)

Thermocouples are used in a wide variety of industrial applications in which they play an important role for temperature control and monitoring. Wire inhomogeneity and hysteresis effects are major sources of uncertainty in thermocouple measurements. To efficiently mitigate these effects, it is first necessary to explore the impact of strain-induced inhomogeneities and hysteresis, and their contribution to the uncertainty. This article investigates homogeneity and hysteresis effects in Types N and K mineral-insulated metal-sheathed (MIMS) thermocouples. Homogeneity of thermocouple wires is known to change when mechanical strain is experienced by the thermoelements. To test this influence, bends of increasingly small radii, typical in industrial applications, were made to a number of thermocouples with different sheath diameters. The change in homogeneity was determined through controlled immersion of the thermocouple into an isothermal liquid oil bath at and was found to be very small at for Type K thermocouples, with no measureable change in Type N thermocouples found. An experiment to determine the hysteresis effect in thermocouples was performed on swaged, MIMS Type N and Type K thermocouples, in the temperature range from to . The hysteresis measurements presented simulate the conditions that thermocouples may be exposed to in industrial applications through continuous cycling over 136 h. During this exposure, a characteristic drift from the reference function has been observed but no considerable difference between the heating and cooling measurements was measureable. The measured differences were within the measurement uncertainties; therefore, no hysteresis was observed.

Pavlasek, P.; Elliott, C. J.; Pearce, J. V.; Duris, S.; Palencar, R.; Koval, M.; Machin, G.

2015-03-01

311

Loops, Polytopes and Splines  

E-print Network

We uncover an unexpected connection between the physics of loop integrals and the mathematics of spline functions. One loop integrands are Laplace transforms of splines. This clarifies the geometry of the associated loop integrals, since a $n$-node spline has support on an $n$-vertex polyhedral cone. One-loop integrals are integrals of splines on a hyperbolic slice of the cone, yielding polytopes in $AdS$ space. Splines thus give a geometrical counterpart to the rational function identities at the level of the integrand. Spline technology also allows for a clear, simple, algebraic decomposition of higher point loop integrals in lower dimensional kinematics in terms of lower point integrals - e.g. an hexagon integral in 2d kinematics can be written as a sum of scalar boxes. Higher loops can also be understood directly in terms of splines - they map onto spline convolutions, leading to an intriguing representation in terms of hyperbolic simplices integrated over other hyperbolic simplices. We finish with speculations on the interpretation of one-loop integrals as partition functions, inspired by the use of splines in counting points in polytopes.

Miguel F. Paulos

2013-04-22

312

SIMON FRASER UNIVERSITY & C.U.P.E., LOCAL 3338 WEIGHTED JOB QUESTIONNAIRE (WJQ) CUSTOM  

E-print Network

SIMON FRASER UNIVERSITY & C.U.P.E., LOCAL 3338 WEIGHTED JOB QUESTIONNAIRE (WJQ) CUSTOM PART 1: JOB account balances, etc., gathering and reviewing procedural information specific to the type of problem

313

Task-parallel global optimization with application to protein folding C. Voglis, P. E. Hadjidoukas,  

E-print Network

Task-parallel global optimization with application to protein folding C. Voglis, P. E. Hadjidoukas, Greece, {voglis,phadjido,dimako,lagaris}@cs.uoi.gr D. G. Papageorgiou Department of Materials Science

Dimakopoulos, Vassilios

314

Large lithium loop experience  

SciTech Connect

An engineering design and operating experience of a large, isothermal, lithium-coolant test loop are presented. This liquid metal coolant loop is called the Experimental Lithium System (ELS) and has operated safely and reliably for over 6500 hours through September 1981. The loop is used for full-scale testing of components for the Fusion Materials Irradiation Test (FMIT) Facility. Main system parameters include coolant temperatures to 430/sup 0/C and flow to 0.038 m/sup 3//s (600 gal/min). Performance of the main pump, vacuum system, and control system is discussed. Unique test capabilities of the ELS are also discussed.

Kolowith, R.; Owen, T.J.; Berg, J.D.; Atwood, J.M.

1981-10-01

315

Multiprotein DNA Looping  

NASA Astrophysics Data System (ADS)

DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switchlike transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.

Vilar, Jose M. G.; Saiz, Leonor

2006-06-01

316

Multiprotein DNA looping  

E-print Network

DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switch-like transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.

Jose M. G. Vilar; Leonor Saiz

2006-06-19

317

Hysteresis effects in x-irradiated KH2PO4, KD2PO4, and RbH2PO4 ferroelectric single crystals observed with electron-spin resonance  

NASA Astrophysics Data System (ADS)

Hysteresis curves were plotted from the ESR spectra of selected x-irradiated potassium dihydrogen phosphate (KDP) type ferroelectric single crystals. The data for the loops were obtained by measuring the difference in intensity of appropriate lines in the ESR spectra of the radicals formed by x irradiation in KH2PO4, KD2PO4, and RbH2PO4. Coercive field values at 90 K varied from 8 to kV/cm. These results are compared to coercive field values reported by other workers for x-irradiated KH2PO4 doped with selenium and arsenic ions.

Truesdale, Roger D.; Farach, Horacio A.; Poole, Charles P., Jr.

1980-07-01

318

Thermodynamic properties and hysteresis behaviors of a mixed spin-3 2 and spin-1 2 Ising double walled ferrielectric nanotubes: A Monte Carlo study  

NASA Astrophysics Data System (ADS)

The hysteresis loops and the thermodynamic properties of a ferroelectric or ferrielectric double walled nanotubes (A and B) are studied within the Ising model with mixed spins (SA =3 2 and SB =1 2 ) in the presence of the crystal and the external longitudinal electric fields. We use the Monte Carlo method to investigate the effects of the external electric field, the crystal field and the exchange interactions on the total polarization, susceptibility, specific heat and the internal energy of a double walled nanotubes (DWNTs).

Benhouria, Y.; Essaoudi, I.; Ainane, A.; Ahuja, R.; Dujardin, F.

2014-11-01

319

Real-space mapping of dynamic phenomena during hysteresis loop measurements: Dynamic Switching Spectroscopy Piezoresponse Force Microscopy  

SciTech Connect

Dynamic switching spectroscopy piezoresponse force microscopy is developed to separate thermodynamic and kinetic effects in local bias-induced phase transitions. The approaches for visualization and analysis of 5D data are discussed. The spatial and voltage variability of relaxation behavior of the a-c domain lead zirconate-titanate surface suggest the interpretation in terms of surface charge dynamics. This approach is applicable to local studies of dynamic behavior in any system with reversible bias-induced phase transitions ranging from ferroelectrics and multiferroics to ionic systems such as Li-ion and oxygen-ion conductors in batteries, fuel cells, and electroresistive systems.

Kumar, Amit [ORNL; Ovchinnikov, Oleg S [ORNL; Jesse, Stephen [ORNL; Kalinin, Sergei V [ORNL

2011-01-01

320

Entropy hysteresis and nonequilibrium thermodynamic efficiency of ion conduction in a voltage-gated potassium ion channel  

NASA Astrophysics Data System (ADS)

Here we have studied the nonequilibrium thermodynamic response of a voltage-gated Shaker potassium ion channel using a stochastic master equation. For a constant external voltage, the system reaches equilibrium indicated by the vanishing total entropy production rate, whereas for oscillating voltage the current and entropy production rates show dynamic hysteretic behavior. Here we have shown quantitatively that although the hysteresis loop area vanishes in low and high frequency domains of the external voltage, they are thermodynamically distinguishable. In the very low frequency domain, the system remains close to equilibrium, whereas at high frequencies it goes to a nonequilibrium steady state (NESS) associated with a finite value of dissipation function. At NESS, the efficiency of the ion conduction can also be related with the nonlinear dependence of the dissipation function on the power of the external field. Another intriguing aspect is that, at the high frequency limit, the total entropy production rate oscillates at NESS with half of the time period of the external voltage.

Das, Biswajit; Banerjee, Kinshuk; Gangopadhyay, Gautam

2012-12-01

321

Application of the Preisach and Jiles{endash}Atherton models to the simulation of hysteresis in soft magnetic alloys  

SciTech Connect

This article describes the advances in unification of model descriptions of hysteresis in magnetic materials and demonstrates the equivalence of two widely accepted models, the Preisach (PM) and Jiles{endash}Atherton (JA) models. Recently it was shown that starting from general energy relations, the JA equation for a loop branch can be derived from PM. The unified approach is here applied to the interpretation of magnetization measured in nonoriented Si{endash}Fe steels with variable grain size {l_angle}s{r_angle}, and also in as-cast and annealed Fe amorphous alloys. In the case of NO Fe{endash}Si, the modeling parameter {ital k} defined by the volume density of pinning centers is such that k{approx}A+B/{l_angle}s{r_angle}, where the parameters {ital A} and {ital B} are related to magnetocrystalline anisotropy and grain texture. The value of {ital k} in the amorphous alloys can be used to estimate the microstructural correlation length playing the role of effective grain size in these materials. {copyright} {ital 1999 American Institute of Physics.}

Pasquale, M.; Bertotti, G. [IEN Galileo Ferraris and INFM, Corso Massimo DAzeglio 42, 10125 Torino (Italy)] [IEN Galileo Ferraris and INFM, Corso Massimo DAzeglio 42, 10125 Torino (Italy); Jiles, D.C.; Bi, Y. [Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)] [Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)

1999-04-01

322

The magnetic hysteresis properties of Ball-milled monodomain titanomagnetite, Fe2.4Ti0.6O4  

NASA Astrophysics Data System (ADS)

Synthetic titanomagnetite, Fe2.4Ti0.6O4 (TM60) was ground in a tungsten carbide ball mill for times up to 80 hours. Initially the material becomes “harder” (coercive force, Hc, and ratio of remanence to saturation, Mr/Ms, rise), which is explicable in terms of reduced particle size and reduced domain wall multiplicity. On further grinding the material becomes “softer”, as expected for monodomain particles with reducing volume. The “optical particle size” of typically 0.4 µm, determined from direct observation by SEM, is, however, ten times bigger than the “magnetic crystal size” inferred from an analysis of the hysteresis loop parameters. The small magnetic crystal size is consistent with the observed X-ray line broadening. The two observations can be reconciled by inspection of Transmission Electron Micrographs which show an internal microstnicture which can be interpreted as the presence of “nanocrystals” within the particle envelope . The production of such nanocrystals by the grinding of particles is described in the materials science literature. It may be that a review of the rock magnetism literature describing the magnetic properties of “crushed grains” will discover features explicable in terms of nanocrystals.

Brown, A. P.; O'Reilly, W.

323

Determination of PRT Hysteresis in the Temperature Range from -50 °C to 300 °C  

NASA Astrophysics Data System (ADS)

This paper discusses the contribution of hysteresis to the measurement uncertainty of industrial platinum resistance thermometers (IPRTs). Hysteresis is one of the sources of uncertainty that has so far not been sufficiently researched and documented. The term hysteresis applies to any system that is path dependent; the output depends on the history of the input. In our case, thermal hysteresis results in different resistance values at the same temperature point, depending on whether the temperature was increasing or decreasing. The reason for such behavior is related to the construction of the thermometer (strain due to thermal expansion and contraction) and also to possible moisture inside the encapsulation. In the process of evaluation of the calibration and measurement capabilities (CMCs) of IPRTs within Working Group 8, the Consultative Committee for Thermometry (CCT WG8) concluded that the uncertainty due to hysteresis is not uniformly defined and not always added to the total uncertainty of the resistance thermometer under calibration. In order to estimate the uncertainty contribution due to the hysteresis and compare different procedures, resistance measurements were carried out on a number of IPRTs of different qualities and tolerance classes. The temperature span was between -50 °C and 300 °C, which is the most frequent temperature range in the practical use of IPRTs. The hysteresis was then determined in different ways (change of resistance at the ice point and at the midpoint temperature according to the ASTM International Standard E644 and according to the new version of IEC Standard 60751), and a comparison of results was made.

Žužek, V.; Batagelj, V.; Bojkovski, J.

2010-09-01

324

Migration of a coarse fluvial sediment pulse detected by hysteresis in bedload generated seismic waves  

NASA Astrophysics Data System (ADS)

Seismic signals near rivers are partially composed of the elastic waves generated by bedload particles impacting the river bed. In this study, we explore the relationship between this seismic signal and river bedload transport by analyzing high-frequency broadband seismic data from multiple stations along the Chijiawan River in northern Taiwan following the removal of a 13 m check dam. This dam removal provides a natural experiment in which rapid and predictable changes in the river's profile occur, which in turn enables independent constraints on spatial and temporal variation in bedload sediment transport. We compare floods of similar magnitudes with and without bedload transport, and find that the amplitude of seismic shaking produced at a given river stage changes over the course of a single storm when bedload transport is active. Hysteresis in the relationship between bedload transport and river stage is a well-documented phenomenon with multiple known causes. Consequently, previous studies have suggested that hysteresis observed in the seismic amplitude-stage response is the signature of bedload transport. Field evidence and stream profile evolution in this study corroborate that interpretation. We develop a metric (?) for the normalized magnitude of seismic hysteresis during individual floods. This metric appears to scale qualitatively with total bedload transport at each seismic station, indicating a dominance of transport on the rising limbs of both storms. We speculate that hysteresis at this site arises from time-dependent evolution of the bed, for example due to grain packing, mobile armoring, or the temporal lag between stage and bedform growth. ? reveals along-stream variations in hysteresis for each storm, with a peak in hysteresis further downstream for the second event. The pattern is consistent with a migrating sediment pulse that is a predicted consequence of the dam removal. Our results indicate that hysteresis in the relationship between seismic wave amplitude and river stage may track sediment transport.

Roth, D. L.; Finnegan, N. J.; Brodsky, E. E.; Cook, K. L.; Stark, C. P.; Wang, H. W.

2014-10-01

325

Hysteresis in In2O3:Zn nanowire field-effect transistor and its application as a nonvolatile memory device  

NASA Astrophysics Data System (ADS)

Control and utilization of hysteresis in nanodevices is an important issue. In this paper, we show an enormous hysteresis in zinc-doped In2O3 nanowire field-effect transistors. Various measurements including changing the operating atmosphere, ozone treatment, and surface passivation were performed to understand and control the hysteresis. The hysteresis could be readily controlled by modifying the nanowire surface. Utilizing the hysteresis, the as-fabricated devices can function as nonvolatile memory elements with high charge storage stability exceeding 4 h. We propose that chemical species such as water molecules adsorbed on the devices and surface oxygen defects in the amorphous layer mainly originated from Zn2+ substitution of In3+ are the main causes of the large hysteresis and the nonvolatile memory effect.

Zhang, Wenfeng; Jie, Jiansheng; Luo, Linbao; Yuan, Guodong; He, Zhubing; Yao, Zhiqiang; Chen, Zhenhua; Lee, Chun-Sing; Zhang, Wenjun; Lee, Shuit-Tong

2008-11-01

326

Deltar beyond one loop  

Microsoft Academic Search

We study the effect of two-loop contributions on the radiative corrections to the muon lifetime in the standard electroweak model. O(alphaalphas) contributions are fully included. We also incorporate all dominant O(alpha2) corrections and identify those logarithms which can be resummed. We present an explicit expression for Deltar which fully exploits our present knowledge of contributions beyond one loop. The phenomenological

Francis Halzen; Bernd A. Kniehl

1991-01-01

327

Hot giant loop holography  

SciTech Connect

We argue that there is a phase transition in the expectation value of the Polyakov loop operator in the large N limit of the high temperature deconfined phase of N=4 Yang-Mills theory on a spatial S{sup 3}. It occurs for the large completely symmetric representation of the SU(N) symmetry group. We speculate that this transition is reflected in the D-branes which are the string theory duals of giant loops.

Grignani, Gianluca [Dipartimento di Fisica, Universita di Perugia, INFN Sezione di Perugia, Via A. Pascoli, 06123 Perugia (Italy); Karczmarek, Joanna L.; Semenoff, Gordon W. [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada)

2010-07-15

328

Thrown for a Loop  

NSDL National Science Digital Library

Students begin to focus on the torque associated with a current carrying loop in a magnetic field. They solve example problems as a class and use diagrams to visualize the vector product. In addition, students learn to calculate the energy of this loop in the magnetic field. Through the associated activity, "Get Your Motor Running," students explore a physical model to gain empirical data and compare it to their calculated data. A homework assignment is also provided as a means of student assessment.

VU Bioengineering RET Program, School of Engineering,

329

The Cinderella Loop Project  

NASA Astrophysics Data System (ADS)

The solar loop observed off the northeast limb on 1999 Nov 6 (a.k.a. the Cinderella Loop) is one of the few examples of a loop on the limb observed with all three of the following imaging instruments: TRACE, EIT on SOHO, and SXT on Yohkoh. In this project we investigate the differences that result when examining the Cinderella Loop with one instrument compared with another. For example, what are the loop temperature and emission measure differences that result from the increased special resolution between the two EUV imagers? More specifically, TRACE and EIT have almost identical temperature responses to coronal plasma. Do the observations taken with the higher-resolution TRACE instrument (with 0.5 arcsec pixels) produce statistically different results than those observations taken with the lower-resolution EIT instrument (with 2.6 arcsec pixels)? In addition, the special resolution of EIT and SXT is similar, but the temperature responses of the two instruments are quite different. Are the two instruments even seeing the same loop strands? If they are, what are the temperatures and emission measures that result from the analysis of the two data sets? How do these results change after background subtraction? This presentation will answer these questions. Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

Schmelz, J.; Beene, J.; Buchanan, J.; Coyle, T.; Douglass, J.; Nasraoui, K.; O'Connor, J.; Roames, J.; Scott, M.

330

Explaining Warm Coronal Loops  

NASA Technical Reports Server (NTRS)

One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense warm loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.

Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros

2008-01-01

331

Changes in Wetting Hysteresis During Bioremediation: Changes in fluid flow behavior monitored with low-frequency seismic attenuation  

Microsoft Academic Search

We observed significant reduction in wetting hysteresis with time while a diesel-contaminated quartz crystal was dipped in and out of an oil-reducing bacteria solution. This wetting hysteresis is significantly greater than the wetting hysteresis when the diesel-contaminated quartz crystal is dipped in and out of (1) water, (2) diesel and (3) the bacterial food solution that does not contain bacteria.

W. Wempe; H. Spetzler; C. Kittleson; J. Pursley

2003-01-01

332

Cloning and characterization of a thermal hysteresis (antifreeze) protein with DNA-binding activity from winter bittersweet nightshade, Solanum dulcamara  

Microsoft Academic Search

The gene for a thermal hysteresis (antifreeze) protein (sthp-64) from the bittersweet nightshade, Solanum dulcamara, was cloned and characterized. An expression cDNA library prepared from November S. dulcamara was screened using a polyclonal antibody generated against a previously purified 67 kDa thermal hysteresis protein, and positive clones were identified and sequenced. The full-length thermal hysteresis protein gene was cloned into an Escherichia

Tao Huang; John G. Duman

2002-01-01

333

Effect of lipids on sorption/desorption hysteresis in natural organic matter.  

PubMed

The chemical composition and physical conformation of natural organic matter (NOM) play a major role in regulating its capacity to retain hydrophobic organic compounds. Naphthalene and phenanthrene were used to study the correlations between sorption/desorption isotherm nonlinearity and compositional data obtained from quantitative (13)C solid-state DPMAS NMR spectroscopy for soil and peat organic matter with or without lipids. Sorption experiments were conducted using a batch equilibration method. Desorption experiments were carried out immediately following the sorption experiments by three successive decant-refill cycles. Hysteresis was observed in all samples. Nonlinear sorption behavior was increased by removal of lipids from the NOM. The hysteresis index, obtained from the ratio of the Freundlich exponents (N values) for the desorption and sorption isotherms, was lower in the lipid-extracted NOM samples than in the same samples without lipid extraction. The relationship between the extent of hysteresis and the characteristics of the (13)C DPMAS NMR spectra indicates that altering NOM composition through lipid extraction not only increased the proportion of aromatic-C content, but also increased sorption/desorption hysteresis. Our data also suggest that the hysteresis index is negatively related to aromaticity. PMID:21458839

Ding, Guangwei; Rice, James A

2011-07-01

334

A Ni-Cd battery model considering state of charge and hysteresis effects  

NASA Astrophysics Data System (ADS)

This paper introduces an electrical battery model. Based on a Thévenin circuit with two RC parallel branches, it includes an ampère-hour counting method to estimate the state of charge (SOC) and a novel model for the hysteresis. The presented model can consider variations in its parameters under changes in all of its internal and external variables, although only SOC and hysteresis are considered. Hysteresis consideration does not only allow distinguishing the parameters during charging and discharging, but also during transients between them. The model was designed to be capable of being implemented in online and offline systems. Finally the proposed model was validated for a single Ni-Cd cell, characterized by current interruption method, in an offline system. The validation was also extended to a stack of 210 cells of the same technology.

García-Plaza, M.; Serrano-Jiménez, D.; Eloy-García Carrasco, J.; Alonso-Martínez, J.

2015-02-01

335

Anomalous optical switching and thermal hysteresis behaviors of VO2 films on glass substrate  

NASA Astrophysics Data System (ADS)

In order to study the optical switching of vanadium dioxide (VO2) and its thermal hysteresis behavior, we fabricated VO2 films on glass substrates at various oxygen pressures. Only the VO2 films made at 5-10 mTorr displayed x-ray diffraction peaks and metal-insulator transition. Upon heating and cooling, remarkably, these samples exhibited significant optical switching behaviors with a clockwise thermal hysteresis in the infrared range of >850 nm or with a counterclockwise thermal hysteresis in the near visible range of 650-850 nm. The temperature dependence of optical absorption was explained by the O2p-V3d splitting depending on the structural transition of VO2.

Li, Jian; Dho, Joonghoe

2011-12-01

336

Modeling biaxial stress effects on magnetic hysteresis in steel with the field and stress axes noncoaxial  

NASA Astrophysics Data System (ADS)

A model based on the domain wall pinning magnetomechanical hysteresis model of Sablik and Jiles [M. J. Sablik and D. C. Jiles, IEEE Trans. Magn. 29, 2113 (1993)] was formulated to compute changes in magnetic hysteresis under biaxial stress conditions with the magnetic field and stress axes noncoaxial. The model included the Villari effect and other asymmetric stress effects. The magnetic field was taken at various angles relative to the stress axis. The Barkhausen noise, hysteresis loss, and maximum flux density were computed for fields varying between ±1 kA/m. The results compared favorably to experimental data on several steels—Polish St3 steel, Polish St41 steel, and US commercial grade steel pipe.

Sablik, M. J.; Augustyniak, B.; Chmielewski, M.

1999-04-01

337

A lumped mucosal wave model of the vocal folds revisited: recent extensions and oscillation hysteresis.  

PubMed

This paper examines an updated version of a lumped mucosal wave model of the vocal fold oscillation during phonation. Threshold values of the subglottal pressure and the mean (DC) glottal airflow for the oscillation onset are determined. Depending on the nonlinear characteristics of the model, an oscillation hysteresis phenomenon may occur, with different values for the oscillation onset and offset threshold. The threshold values depend on the oscillation frequency, but the occurrence of the hysteresis is independent of it. The results are tested against pressure data collected from a mechanical replica of the vocal folds, and oral airflow data collected from speakers producing intervocalic /h/. In the human speech data, observed differences between voice onset and offset may be attributed to variations in voice pitch, with a very small or inexistent hysteresis phenomenon. PMID:21428520

Lucero, Jorge C; Koenig, Laura L; Lourenço, Kelem G; Ruty, Nicolas; Pelorson, Xavier

2011-03-01

338

The Cinderella loop project  

NASA Astrophysics Data System (ADS)

The solar loop that formed off the northeast limb of the Sun on 1999 November 6 (a.k.a. the Cinderella loop) is one of the few examples of a loop on the limb observed with all three of the following imaging instruments: the Transition Region and Coronal Explorer (TRACE), the SOHO Extreme-ultraviolet Imaging Telescope (EIT), and the Yohkoh Soft X-ray Telescope (SXT). In this project we investigate the temperature differences that result when examining the Cinderella loop with one instrument compared with another. For example, what temperature differences result from the increased spatial resolution between the two EUV imagers? More specifically, given that TRACE and EIT have almost identical temperature response to coronal plasma, does the different spatial resolution of TRACE (with 0.5? pixels) and EIT (with 2.6? pixels) produce statistically different results? We find that the answer is no, and that our results do not change after background subtraction. In addition, the spatial resolution of EIT and SXT is similar, but the temperature responses of the two instruments are quite different. The two instruments do not seem to be viewing the same loop strands, and the plasma temperature differences are significant.

Schmelz, J. T.; Beene, J.; Coyle, T.; Douglass, J.; Nasraoui, K.; O'Connor, J.; Roames, J.; Scott, M.

2006-01-01

339

A neural model of hysteresis in amorphous materials and piezoelectric materials  

NASA Astrophysics Data System (ADS)

A new approach to constructing hysteretic operator (HO) is proposed in this paper. Based on the HO, the input space of neural networks is expanded from one-dimension to two-dimension and the multi-value mapping of hysteresis is transformed into a continuous mapping comprised of one-to-one mapping and multiple-to-one mapping. Based on the expanded input space, a neural network is employed to approximate hysteresis. The results of experimental examples suggest the proposed approach is effective.

Ma, Lianwei; Shen, Yu

2014-08-01

340

Effect of twist process on critical current and hysteresis loss of Nb 3Sn strands  

NASA Astrophysics Data System (ADS)

We have prepared Nb 3Sn strands by the internal tin process for superconducting conductor application in the international thermonuclear experimental reactor (ITER). The multifilamentary Nb 3Sn strands have a diameter of 0.82 mm and a unit length longer than 5000 m. We have investigated the effect of twist process on superconducting critical current density and hysteresis loss for Nb 3Sn strands. It has been found that the twist process significantly reduces the hysteresis loss of the strands, while the critical current density and the n-value remain nearly unchanged.

Zhang, P. X.; Zhou, L.; Tang, X. D.; Liang, M.; Li, C. G.; Wu, Y.; Yan, G.; Yang, M.; Feng, Y.; Liu, X. H.; Weng, P. D.; Lu, Y. F.

2007-10-01

341

The Anderson Current Loop  

NASA Technical Reports Server (NTRS)

Four-wire-probe concept applied to electrical-resistance transducers. Anderson current loop is excitation-and-signal-conditioning circuit suitable for use with strain gauges, resistance thermometers, and other electrical-resistance transducers mounted in harsh environments. Used as alternative to Wheatstone bridge. Simplifies signal-conditioning problem, enabling precise measurement of small changes in resistance of transducer. Eliminates some uncertainties in Wheatstone-bridge resistance-change measurements in flight research. Current loop configuration makes effects of lead-wire and contact resistances insignificantly small. Also provides output voltage that varies linearly with change in gauge resistance, and does so at double sensitivity of Wheatstone bridge.

Anderson, Karl F.

1994-01-01

342

Loop Quantum Gravity  

E-print Network

This article presents an "in-a-nutshell" yet self-contained introductory review on loop quantum gravity (LQG) -- a background-independent, nonperturbative approach to a consistent quantum theory of gravity. Instead of rigorous and systematic derivations, it aims to provide a general picture of LQG, placing emphasis on the fundamental ideas and their significance. The canonical formulation of LQG, as the central topic of the article, is presented in a logically orderly fashion with moderate details, while the spin foam theory, black hole thermodynamics, and loop quantum cosmology are covered briefly. Current directions and open issues are also summarized.

Dah-Wei Chiou

2014-12-14

343

The Effect of Films on the Capillary Pressure - Saturation Hysteresis in a Smooth-walled Wedge Channel  

NASA Astrophysics Data System (ADS)


Thin fluid films are central to many multiphase flow applications; however, experimental investigation of films requires direct detection and measurement of films. Water film thicknesses can range from a few nanometers to several micrometers and may vary depending on local pore structures and material properties. In this study, laser confocal microscopy was employed to image volumetric fluid distribution and 3D interfaces during drainage and imbibition processes in a smooth-walled channel. Confocal microscopy provides an effective method to image directly 3D thin films and to measure film thickness, volume, and other parameters. The detection resolution is 1.19 ?m/pixel through a 10x objective lens and is 0.72 ?m/pixel through a 20x lens. A smooth-walled wedge channel was fabricated to study the generation and relaxation of water films in the non-wetting phase of air. The effect of films on contact angle, interfacial area per volume (IAV), and capillary pressure - saturation (Pc - Sw) hysteresis were also investigated.
Micromodels were fabricated using a negative photoresist (SU-8) sandwiched between two cover glasses. An all-SU-8 smooth-walled wedge channel was fabricated by laser direct-writing two-photon polymerization, 100 ?m wide at the outlet and 20 ?m at the inlet with a constant aperture of 40 ?m. A laser scanning confocal microscope was used to image the wetting (water) and non-wetting (air) phase distributions by labeling the wetting phase with a fluorophore, Alex Fluor-488, 1.0% by wieght. The 3D air-water interfaces were imaged and then reconstructed using a stack of confocal images. The samples were initially saturated with water, the wetting phase. A series of drainage and imbibition cycles were performed by incrementing or decrementing the air pressure. At each pressure, the system was allowed to equilibrate and then a stack of scans in depth was collected to acquire the 3D fluid distribution for the given pressure. The confocal images were analyzed to extract the volume saturation of water, IAV, and contact angle.
Thin films of water between the air and the solid phase (SU-8 channel) were observed in the wedge micro-channel. The presence of films were found to increase the capillary pressure relative to the condition with no films by 0 ~ 1300 Pa as a function of wetting phase saturation. Force balance analysis was performed based on the contact angle at the common line, which shows an additional surface tension from the film that is approximately 1/10 that of the water surface tension. The same energy expended for the hysteresis loops was found between with and without film. In addition, only partial film relaxation is observed when a hysteresis scan is paused.
Acknowledgments: This research is supported by the National Science Foundation (0911284-EAR).

Liu, Y.; Nolte, D.; Pyrak-Nolte, L. J.

2010-12-01

344

A comparison of analytic and bayesian approaches for characterizing thermal hysteresis in cattle using algebraic and geometric distances  

Technology Transfer Automated Retrieval System (TEKTRAN)

A high ambient temperature poses a serious threat to cattle. Above a certain threshold, an animal’s body temperature (Tb) appears to be driven by the hot cyclic air temperature (Ta) and hysteresis occurs. Elliptical hysteresis describes the output of a process in response to a simple harmonic input,...

345

A time-based double-band hysteresis current regulation strategy for single-phase multilevel inverters  

Microsoft Academic Search

Most multilevel inverter hysteresis current regulators use either multiple hysteresis bands, or a time-based switching logic that forces the current error back to zero by recursively stepping through successive voltage levels. Of these two alternatives, the time-based approach has the merit of only requiring simple analog circuitry and digital logic to implement the voltage level selection process for inverters of

Poh Chiang Loh; Gerwich H. Bode; Donald Grahame Holmes; Thomas A. Lipo

2003-01-01

346

Feedforward controller based-on piezoelectric actuator's hysteresis model and its performance simulation of an XY plane motion stage  

Microsoft Academic Search

The piezoelectric actuator is a perfect nano-positioning drive element for its good performance except its hysteresis, creep, and nonlinearity, which make its control difficult. This paper proposed a control design methodology based on piezoelectric actuator's hysteresis model. First system identifying experiments were performed to identify the system model of a XY serial kinematics plane nanopositioning stage employing piezoelectric actuators. The

Pan Lizhi; Zhan Min; Wang Wendong; Liang Yakun

2009-01-01

347

Closing the Loop Sampler.  

ERIC Educational Resources Information Center

Closing the Loop (CTL) is a science curriculum designed to introduce students to integrated waste management through awareness. This document presents five lesson plans focusing on developing an understanding of natural resources, solid wastes, conservation, and the life of landfills. Contents include: (1) "What Are Natural Resources?"; (2)…

California Integrated Waste Management Board, Sacramento.

348

Closing the Assessment Loop  

ERIC Educational Resources Information Center

Accreditors, speakers at assessment conferences, and campus leaders all decry the fact that too few faculty are closing the loop--that is, studying assessment findings to see what improvements might be suggested and taking the appropriate steps to make them. This is difficult enough with locally developed measures; adding the need to interpret…

Banta, Trudy W.; Blaich, Charles

2011-01-01

349

Temporal Resolution [Loop Search  

E-print Network

perform the following steps. 1. Transform A into SNF, giving a set of clauses AS. 2. Perform step Logic [TEMPORAL RESOLUTION: LOOP SEARCH] ­ p.2/24 #12;Merged SNF To apply the temporal resolution rule, it is often convenient to combine one or more step clauses. Consequently, a variant on SNF called merged-SNF

Fisher, Michael

350

Loop heat pipes  

Microsoft Academic Search

Loop heat pipes (LHPs) are two-phase heat-transfer devices with capillary pumping of a working fluid. They possess all the main advantages of conventional heat pipes, but owing to the original design and special properties of the capillary structure are capable of transferring heat efficiency for distances up to several meters at any orientation in the gravity field, or to several

Yu. F. Maydanik

2005-01-01

351

NETL - Chemical Looping Reactor  

ScienceCinema

NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

None

2014-06-26

352

NETL - Chemical Looping Reactor  

SciTech Connect

NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

None

2013-07-24

353

CURRICULUM VITAE OF MARK L. NAGURKA, Ph.D., P.E.  

E-print Network

CURRICULUM VITAE OF MARK L. NAGURKA, Ph.D., P.E. October 2014 Present Position: Associate Professor Massachusetts Institute of Technology, Cambridge, MA 02139 (Thesis: Curving Performance of Rail Passenger & Controls: Mechatronics (sensors, actuators, controls, and design). System dynamics modeling and simulation

Nagurka, Mark L.

354

CURRICULUM VITAE OF MARK L. NAGURKA, Ph.D., P.E.  

E-print Network

CURRICULUM VITAE OF MARK L. NAGURKA, Ph.D., P.E. July 2014 Present Position: Associate Professor Massachusetts Institute of Technology, Cambridge, MA 02139 (Thesis: Curving Performance of Rail Passenger & Controls: Mechatronics (sensors, actuators, controls, and design). System dynamics modeling and simulation

Nagurka, Mark L.

355

Use of Hydrogen Peroxide in Finfish Aquaculture1 Roy P. E. Yanong2  

E-print Network

FA157 Use of Hydrogen Peroxide in Finfish Aquaculture1 Roy P. E. Yanong2 1. This document is FA157/IFAS Extension. Introduction Hydrogen peroxide is commonly used as a disinfectant for cleaning wounds in people. Hydrogen peroxide has also been used in aquaculture as an immersion (bath) treatment against many different

Watson, Craig A.

356

Page 1 of 8 SIMON FRASER UNIVERSITY & C.U.P.E., LOCAL 3338  

E-print Network

Page 1 of 8 SIMON FRASER UNIVERSITY & C.U.P.E., LOCAL 3338 WEIGHTED JOB QUESTIONNAIRE (WJQ) CUSTOM PART 1: JOB DESCRIPTION 1. POSITION IDENTIFICATION FOR USE BY HUMAN RESOURCES Department Name record information and clarifies admissions information specific to student's Basis of Admission and file

357

Page 1 of 9 SIMON FRASER UNIVERSITY & C.U.P.E., LOCAL 3338  

E-print Network

Page 1 of 9 SIMON FRASER UNIVERSITY & C.U.P.E., LOCAL 3338 WEIGHTED JOB QUESTIONNAIRE (WJQ) CUSTOM PART 1: JOB DESCRIPTION 1. POSITION IDENTIFICATION FOR USE BY HUMAN RESOURCES Department Name) and ad hoc events. Compiles data from other sources to generate new databases for specific events

358

Water, Inertial Damping, and the Complex Shear Modulus Paul Michaels, M. ASCE, P.E.  

E-print Network

Water, Inertial Damping, and the Complex Shear Modulus Paul Michaels, M. ASCE, P.E. Professor for saturated permeable soils. Thus represented, the imaginary part of the complex shear modulus will vary of view, Kramer (1996) gives a derivation for the damping ratio, as (3) The shear modulus, G, may also

Barrash, Warren

359

C A M P E P Commission on Accreditation of Medical Physics Educational Programs, Inc.  

E-print Network

C A M P E P Commission on Accreditation of Medical Physics Educational Programs, Inc. Sponsoring of the Commission on Accreditation of Medical Physics Educational Programs (CAMPEP), I am pleased to inform you Physics Ellipse, College Park, MD20740, Tel. (301) 209-3346, Fax. (301) 209-0862, E-mail. campep

Hemmers, Oliver

360

Career of the Month: An Interview with Aquaculture Veterinarian Roy P.E. Yanong  

NSDL National Science Digital Library

Did you know that fish have doctors too? Although this may sound "fishy", it's true! In this issue's Career of the Month column, you'll meet fish doctor Roy P.E. Yanong, an Aquaculture Veterinarian, and discover this intriguing career in the process.

Megan Sullivan

2005-07-01

361

Dynamic Tensile Testing of Kevlar 49 Fabrics ; Barzin Mobasher, Ph.D., P.E.2  

E-print Network

Dynamic Tensile Testing of Kevlar 49 Fabrics Deju Zhu1 ; Barzin Mobasher, Ph.D., P.E.2 of strain. Kevlar-49 fabrics were tested in tension within a strain-rate range of 25 to 170 sÀ1 using a high nature of Kevlar-49 fabric results in large displacements and shape changes during tests. Noncontacting

Mobasher, Barzin

362

The College of Engineering Dean: Khosrow Behbehani, Ph.D., P.E.  

E-print Network

except software engineering, engineering management, logistics, and systems engineering, which offerThe College of Engineering Dean: Khosrow Behbehani, Ph.D., P.E. 634 Nedderman Hall · Box 19019 · 817-272-2571 www.uta.edu/engineering Overview Engineering is the profession in which a knowledge

Texas at Arlington, University of

363

A p p e n d i x J Media, Nutrition,  

E-print Network

J­1 j A p p e n d i x J Media, Nutrition, and Physical Activity Resources The following resources these organizations or their positions. #12;Appendix J--Media, Nutrition, and Physical Activity ResourcesJ­2 Nameand Nutrition Focus Calcium Focus Media Info ActionforHealthyKids http://www. actionforhealthykids.org/ (800

Rau, Don C.

364

LANDSLIDE STABILIZATION USING GEOFOAM G. MANN, P. E., President, Creative Engineering Options, Inc., 5418 159th  

E-print Network

LANDSLIDE STABILIZATION USING GEOFOAM G. MANN, P. E., President, Creative Engineering Options, Inc describes a landslide that utilizes geofoam and involves a single family residence near Seattle, Washington. Historically this western slope experienced several landslide events. This activity has slowly dragged soil

365

[LR7573E]059101PRE Contact-angle hysteresis in solid-on-solid wetting  

E-print Network

PROOF COPY [LR7573E]059101PRE Contact-angle hysteresis in solid-on-solid wetting Phil Attard Ian the solid surfaces. The deformation and contact area are obtained self-consistently as a function of load depend upon the interfacial energies of the phases. For a liquid drop on a solid in a vapor the Young

Attard, Phil

366

A stability-based mechanism for hysteresis in the walk–trot transition in quadruped locomotion  

PubMed Central

Quadrupeds vary their gaits in accordance with their locomotion speed. Such gait transitions exhibit hysteresis. However, the underlying mechanism for this hysteresis remains largely unclear. It has been suggested that gaits correspond to attractors in their dynamics and that gait transitions are non-equilibrium phase transitions that are accompanied by a loss in stability. In the present study, we used a robotic platform to investigate the dynamic stability of gaits and to clarify the hysteresis mechanism in the walk–trot transition of quadrupeds. Specifically, we used a quadruped robot as the body mechanical model and an oscillator network for the nervous system model to emulate dynamic locomotion of a quadruped. Experiments using this robot revealed that dynamic interactions among the robot mechanical system, the oscillator network, and the environment generate walk and trot gaits depending on the locomotion speed. In addition, a walk–trot transition that exhibited hysteresis was observed when the locomotion speed was changed. We evaluated the gait changes of the robot by measuring the locomotion of dogs. Furthermore, we investigated the stability structure during the gait transition of the robot by constructing a potential function from the return map of the relative phase of the legs and clarified the physical characteristics inherent to the gait transition in terms of the dynamics. PMID:23389894

Aoi, Shinya; Katayama, Daiki; Fujiki, Soichiro; Tomita, Nozomi; Funato, Tetsuro; Yamashita, Tsuyoshi; Senda, Kei; Tsuchiya, Kazuo

2013-01-01

367

Sensitivity of sulfate direct climate forcing to the hysteresis of particle phase transitions  

E-print Network

, focusing on the sulfate-ammonium system. The phase transition affects the hygroscopic behavior]. The composition of sulfate-ammonium particles is charac- terized by the extent of neutralization, defined as XSensitivity of sulfate direct climate forcing to the hysteresis of particle phase transitions Jun

368

Cochlear hysteresis: Observation with low-frequency modulated distortion product otoacoustic emissions  

E-print Network

Cochlear hysteresis: Observation with low-frequency modulated distortion product otoacoustic of the MPs occurred at positive sound pressures for rising in bias pressure or loading of the cochlear levels. Both physiologic indices and model parameters suggest that the cochlear transducer dynamically

Allen, Jont

369

FORWARD HYSTERESIS AND BACKWARD BIFURCATION CAUSED BY CULLING IN AN AVIAN INFLUENZA MODEL  

E-print Network

FORWARD HYSTERESIS AND BACKWARD BIFURCATION CAUSED BY CULLING IN AN AVIAN INFLUENZA MODEL HAYRIYE influenza virus strain magnifies the need for controlling the incidence of H5N1 infection in domestic bird measure. We use mathematical modeling to understand the dynamics of avian influenza under different

Martcheva, Maia

370

Ultra-precise tracking control of piezoelectric actuators via a fuzzy hysteresis model.  

PubMed

In this paper, a novel Takagi-Sugeno (T-S) fuzzy system based model is proposed for hysteresis in piezoelectric actuators. The antecedent and consequent structures of the fuzzy hysteresis model (FHM) can be, respectively, identified on-line through uniform partition approach and recursive least squares (RLS) algorithm. With respect to controller design, the inverse of FHM is used to develop a feedforward controller to cancel out the hysteresis effect. Then a hybrid controller is designed for high-performance tracking. It combines the feedforward controller with a proportional integral differential (PID) controller favourable for stabilization and disturbance compensation. To achieve nanometer-scale tracking precision, the enhanced adaptive hybrid controller is further developed. It uses real-time input and output data to update FHM, thus changing the feedforward controller to suit the on-site hysteresis character of the piezoelectric actuator. Finally, as to 3 cases of 50 Hz sinusoidal, multiple frequency sinusoidal and 50 Hz triangular trajectories tracking, experimental results demonstrate the efficiency of the proposed controllers. Especially, being only 0.35% of the maximum desired displacement, the maximum error of 50 Hz sinusoidal tracking is greatly reduced to 5.8 nm, which clearly shows the ultra-precise nanometer-scale tracking performance of the developed adaptive hybrid controller. PMID:22938339

Li, Pengzhi; Yan, Feng; Ge, Chuan; Zhang, Mingchao

2012-08-01

371

Hysteresis, Discrete Memory, and Nonlinear Wave Propagation in Rock: A New Paradigm  

Microsoft Academic Search

The structural elements in a rock are characterized by their density in Preisach-Mayergoyz space (PM space). This density is found for a Berea sandstone from stress-strain data and used to study the response of the sandstone to elaborate pressure protocols. Hysteresis with discrete memory, in agreement with experiment, is found. The relationship between strain, quasistatic modulus, and dynamic modulus is

R. A. Guyer; K. R. McCall; G. N. Boitnott

1995-01-01

372

Simulation of AV hysteresis pacing using an integrated dual chamber heart and pacer model  

Microsoft Academic Search

Long term right ventricular apical pacing has been known to have adverse effects in cardiac function. The AV hysteresis (AVH) is a feature existing in many dual-chamber cardiac pacemakers that aims to minimize the right ventricular pacing, but its clinical efficacy remains inconclusive due to conflicting evidence from different studies. We have recently developed a novel integrated dual-chamber heart and

Jie Lian; Garth Garner; Hannes Krätschmer; Dirk Müssig

2009-01-01

373

Adaptive wavelet neural network control with hysteresis estimation for piezo-positioning mechanism.  

PubMed

An adaptive wavelet neural network (AWNN) control with hysteresis estimation is proposed in this study to improve the control performance of a piezo-positioning mechanism, which is always severely deteriorated due to hysteresis effect. First, the control system configuration of the piezo-positioning mechanism is introduced. Then, a new hysteretic model by integrating a modified hysteresis friction force function is proposed to represent the dynamics of the overall piezo-positioning mechanism. According to this developed dynamics, an AWNN controller with hysteresis estimation is proposed. In the proposed AWNN controller, a wavelet neural network (WNN) with accurate approximation capability is employed to approximate the part of the unknown function in the proposed dynamics of the piezo-positioning mechanism, and a robust compensator is proposed to confront the lumped uncertainty that comprises the inevitable approximation errors due to finite number of wavelet basis functions and disturbances, optimal parameter vectors, and higher order terms in Taylor series. Moreover, adaptive learning algorithms for the online learning of the parameters of the WNN are derived based on the Lyapunov stability theorem. Finally, the command tracking performance and the robustness to external load disturbance of the proposed AWNN control system are illustrated by some experimental results. PMID:16566470

Lin, Faa-Jeng; Shieh, Hsin-Jang; Huang, Po-Kai

2006-03-01

374

Calculation of hysteresis losses in hard superconductors carrying ac: isolated conductors and edges of thin sheets  

Microsoft Academic Search

Two methods of calculating hysteresis losses in hard superconductors are described. The London model is assumed in which the critical current density is taken independent of magnetic field. Losses in isolated wires of different cross section are considered but it is found that losses for solid wires vary by at most a factor of 3 for different shaped wires of

W T Norris

1970-01-01

375

Ultra-precise tracking control of piezoelectric actuators via a fuzzy hysteresis model  

NASA Astrophysics Data System (ADS)

In this paper, a novel Takagi-Sugeno (T-S) fuzzy system based model is proposed for hysteresis in piezoelectric actuators. The antecedent and consequent structures of the fuzzy hysteresis model (FHM) can be, respectively, identified on-line through uniform partition approach and recursive least squares (RLS) algorithm. With respect to controller design, the inverse of FHM is used to develop a feedforward controller to cancel out the hysteresis effect. Then a hybrid controller is designed for high-performance tracking. It combines the feedforward controller with a proportional integral differential (PID) controller favourable for stabilization and disturbance compensation. To achieve nanometer-scale tracking precision, the enhanced adaptive hybrid controller is further developed. It uses real-time input and output data to update FHM, thus changing the feedforward controller to suit the on-site hysteresis character of the piezoelectric actuator. Finally, as to 3 cases of 50 Hz sinusoidal, multiple frequency sinusoidal and 50 Hz triangular trajectories tracking, experimental results demonstrate the efficiency of the proposed controllers. Especially, being only 0.35% of the maximum desired displacement, the maximum error of 50 Hz sinusoidal tracking is greatly reduced to 5.8 nm, which clearly shows the ultra-precise nanometer-scale tracking performance of the developed adaptive hybrid controller.

Li, Pengzhi; Yan, Feng; Ge, Chuan; Zhang, Mingchao

2012-08-01

376

Towards a truck-driver model using a hysteresis based analysis and verification approach  

E-print Network

Towards a truck-driver model using a hysteresis based analysis and verification approach (Extended this methodology, we reuse a car driver model and build a truck driver model by considering relevant aspects. We. In this work we propose to produce a model of the behav- ior of truck drivers, which are known to have

377

Thermodynamic Analysis of Snowball Earth Hysteresis Experiment: Efficiency, Entropy Production, and Irreversibility  

Microsoft Academic Search

We present an extensive thermodynamic analysis of a hysteresis experiment performed on a simplified yet Earth-like climate model. We slowly vary the solar constant by 20% around the present value and detect that for a large range of values of the solar constant the realization of snowball or of regular climate conditions depends on the history of the system. Using

Valerio Lucarini; Klaus Fraedrich; Frank Lunkeit

2010-01-01

378

The role of transport phenomena on efficacy, stability and hysteresis in encapsulated cellular systems  

Microsoft Academic Search

Multiple steady states are possible when transport limitations are imposed on cellular systems that exhibit some level of substrate inhibition. These distinct steady states can be achieved under identical operating conditions such as temperature, flowrate, and composition. Cells will exhibit different metabolisms depending on their environmental history and the path taken to the specific reactor operating conditions. Hysteresis is observed

Susan C. Roberts; Robert J. Fisher

2000-01-01

379

Strain and hysteresis by stochastic matrix cracking in ceramic matrix composites  

Microsoft Academic Search

A theory is presented to predict the stress\\/strain relations and unload\\/reload hysteresis behavior during the evolution of multiple matrix cracking in unidirectional fiber reinforced ceramic matrix composites (CMCs). The theory is based on the similarity between multiple matrix cracking and fiber fragmentation in a single fiber composite, and determines the crack and strain evolution as a function of the statistical

B. K. Ahn; W. A. Curtin

1997-01-01

380

Relationships between hysteresis measurements and the constituent properties of ceramic matrix composites. 1: Theory  

Microsoft Academic Search

A methodology for assessing constituent properties of ceramic matrix composites (CMCs) from stress\\/strain curves is developed. The procedures demonstrate how the properties of the interface and the misfit strain can be related to the unload\\/reload hysteresis and the permanent strain. The approach is illustrated in companion papers by obtaining experimental measurements on two CMCs. The results demonstrate why differences in

Emmanuel Vagaggini; Jean-Marc Domergue; Anthony G. Evans

1995-01-01

381

Fractal analysis of soil water hysteresis as influenced by sewage sludge application  

E-print Network

, and the air/water displacement suction), and A2 (a compound parameter that includes D2, and the critical, were significantly affected by hysteresis and/or the sludge treatments for the loam soil. Values of A1 of the loam soil. © 2006 Elsevier B.V. All rights reserved. 1. Introduction Continuous human population growth

Perfect, Ed

382

A new simple asymmetric hysteresis operator and its application to inverse control of piezoelectric actuators.  

PubMed

Piezoelectric actuators (PEAs) are commonly used as micropositioning devices due to their high resolution, high stiffness, and fast frequency response. Because piezoceramic materials are ferroelectric, they fundamentally exhibit hysteresis behavior in their response to an applied electric field. The positioning precision can be significantly reduced due to nonlinear hysteresis effects when PEAs are used in relatively long range applications. This paper describes a new, precise, and simple asymmetric hysteresis operator dedicated to PEAs. The complex hysteretic transfer characteristic has been considered in a purely phenomenological way, without taking into account the underlying physics. This operator is based on two curves. The first curve corresponds to the main ascending branch and is modeled by the function f1. The second curve corresponds to the main reversal branch and is modeled by the function g2. The functions f(1) and g(2) are two very simple hyperbola functions with only three parameters. Particular ascending and reversal branches are deduced from appropriate translations of f(1) and g(2). The efficiency and precision of the proposed approach is demonstrated, in practice, by a real-time inverse feed-forward controller for piezoelectric actuators. Advantages and drawbacks of the proposed approach compared with classical hysteresis operators are discussed. PMID:18519217

Badel, A; Qiu, J; Nakano, T

2008-05-01

383

Experimental investigation on hysteresis effect of refrigerant flowing through a coiled adiabatic capillary tube  

Microsoft Academic Search

This paper experimentally investigates the mass flow rate hysteresis of R22 in a coiled adiabatic capillary tube. The measured mass flow rate data in a coiled adiabatic capillary are found to be more dispersive than those in a straight one. The scatter bands of measured data are significantly dependent on how the state points are achieved. For increasing inlet subcooling

Zhou Guobing; Zhang Yufeng

2006-01-01

384

Hysteresis and self-sustained oscillations in space charge limited currents  

Microsoft Academic Search

A problem of charged particle flow between parallel plate electrodes with arbitrary injection velocities is revisited. A steady-state analysis is advanced by the kinetic simulations which show that the system under consideration can exhibit features characteristic of nonlinear dynamical systems. In particular, a hysteresis between supply limited and space charge limited currents is demonstrated as well as the existence of

Yu. N. Gartstein; P. S. Ramesh

1998-01-01

385

Incorporating core hysteresis properties in three-dimensional computations of transformer inrush current forces  

Microsoft Academic Search

It is well known that transformer inrush currents depend upon the core properties, residual flux, switching instant, and the overall circuit parameters. Large transient inrush currents introduce abnormal electromagnetic forces which may destroy the transformer windings. This paper presents an approach through which core hysteresis may be incorporated in three-dimensional computations of transformer inrush current forces. Details of the approach,

A. A. Adly; H. H. Hanafy

2009-01-01

386

Hysteresis operators in phase-field models of Penrose-fife type  

Microsoft Academic Search

Phase-field systems as mathematical models for phase transitions have drawn a considerable attention in recent years. However, while they are suitable for capturing many of the experimentally observed phenomena, they are only of restricted value in modelling hysteresis effects occurring during phase transition processes. To overcome this shortcoming of existing phase-field theories, the authors have recently proposed a new approach

Pavel Krej?í; Jürgen Sprekels

1998-01-01

387

Series and parallel operation of hysteresis current-controlled PWM rectifiers  

Microsoft Academic Search

Different strategies for series and parallel connections of hysteresis current-controlled PWM rectifier have been investigated by experiments, computer simulations, and analyses. Each rectifier unit delivers near-sinusoidal current waveforms at unity (or even leading) power factor. Of particular concern are the questions of: (i) system stability; (ii) the capability of the modular units to share voltage (series connection) and current (parallel

J. W. Dixon; B. T. Ooi

1989-01-01

388

Calculation of the magnetic field in the active zone of a hysteresis clutch  

NASA Technical Reports Server (NTRS)

The initial distribution of magnetic induction in the armature stationary was calculated relative to the polar system of a hysteresis clutch. Using several assumptions, the problem is reduced to calculating the static magnetic field in the ferromagnetic plate with finite and continuous magnetic permeability placed in the air gap between two identical, parallel semiconductors with rack fixed relative to the tooth or slot position.

Ermilov, M. A.; Glukhov, O. M.

1977-01-01

389

Control of deep-hysteresis aeroengine compressors. II. Design of control laws  

Microsoft Academic Search

In this paper we continue the development of a methodology for control of deep-hysteresis compressors initiated in a companion paper. We develop a family of controllers which are applicable not only to the particular model presented in Part I of this paper, but also to general Moore-Greitzer type models with arbitrary compressor characteristics. For each of our controllers we show

Miroslav KrstiC; Hsin-Hsiung Wang

1997-01-01

390

Scaling behavior of hysteresis in multilayer MoS{sub 2} field effect transistors  

SciTech Connect

Extrinsic hysteresis effects are often observed in MoS{sub 2} field effect devices due to adsorption of gas molecules on the surface of MoS{sub 2} channel. Scaling is a common method used in ferroics to quantitatively study the hysteresis. Here, the scaling behavior of hysteresis in multilayer MoS{sub 2} field effect transistors with a back-gated configuration was investigated. The power-law scaling relations were obtained for hysteresis area (?A?) and memory window (?V) with varying the region of back-gate voltage (V{sub bg,max}). It is interesting to find that the transition voltage in the forward sweep (V{sub FW}) and in the backward sweep (V{sub BW}) shifted to the opposite directions of back-gate voltage (V{sub bg}) with increasing V{sub bg,max}. However, when decreasing V{sub bg,max}, V{sub FW} shifted to positive and reversibly recovered, but V{sub BW} almost kept unchanged. The evolution of ?A?, ?V, V{sub FW,} and V{sub BW} with V{sub bg,max} were discussed by the electrons transferring process between the adsorbate and MoS{sub 2} channel.

Li, Tao; Du, Gang; Zhang, Baoshun; Zeng, Zhongming, E-mail: zmzeng2012@sinano.ac.cn [Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Ruoshui Road 398, Suzhou 215123 (China)

2014-09-01

391

Pore-scale mechanisms for hysteresis in capillary-dominated drainage and imbibition (Invited)  

NASA Astrophysics Data System (ADS)

Understanding the flow of two immiscible fluid phases through the pore space of rocks and soils is a complex problem involving fluid dynamics, surface science and geometry. Invariably one fluid, usually water, preferentially coats the solid surface. Of major interest, and a significant challenge for multiphase fluid modelling, is the fact that the flow displays hysteresis: the measured difference in pressure between fluids (the capillary pressure) is higher when the water is draining out than when it is imbibing back in. One consequence of this hysteresis include capillary trapping, of relevance to waterflooding oil recovery and geosequestration of CO¬2. While several models have attempted with mixed success to capture this hysteresis at the macro-scale, no consensus yet exists on its pore-scale causes. The current work makes use of X-ray micro-tomography (MCT) data to help identify resolve this question. We first enumerate the different mechanisms that have been proposed in the literature for this hysteresis. We break these mechanisms into two categories: local mechanisms that may occur inside a single geometric feature (such as a pore or throat) and those that may only be observed within some sort of labyrinth. Local mechanisms include contact angle hysteresis (induced by surface, chemistry surface roughness and/or interface pinning), the ink-bottle effect and geometric bistability associated with the stability of both main terminal menisci and arc menisci in a constrictive pore space element. The nonlocal mechanisms are fluid trapping (possible for both wetting and nonwetting fluids) and structure hysteresis arising from heterogeneity in the pore system. Our results arise from the analysis of imaging experiments in which water was successively imbibed into and drained from small samples of Bentheimer sandstone and unconsolidated grain packs. The experiment were conducted at both synchrotron and laboratory X-ray MCT facilities, with both imaging setups having sufficient resolution to show the distribution of the two fluid phases throughout the material while also capturing fluid menisci in individual pores. We apply a range of topological and geometric analyses to these images, most notably the calculation of Betti numbers, interfacial area and interfacial curvature, to quantify the differences in fluid configurations during imbibition and drainage. While our results suggest that geometric bistability may be the primary cause for hysteresis in these particular experiments, we discuss the significance of our results and suggest that far more work is needed before definitive conclusions can be drawn.

Sheppard, A.; Wildenschild, D.; Andersson, L.; Herring, A. L.

2013-12-01

392

Transient hysteresis of near-surface permafrost response to external forcing  

NASA Astrophysics Data System (ADS)

Estimates of changes in near-surface permafrost (NSP) area S p relative to change in globally averaged surface air temperature T g are made by using the global climate model developed at the A.M. Obukhov Institute of Atmospheric Physics RAS (IAP RAS CM). For ensemble of runs forced by scenarios constructed as return-to-preindustrial continuations of the RCP (Representative Concentration Pathways) scenarios family, a possibility of transient hysteresis in dependence of S p versus T g is exhibited: in some temperature range which depends on imposed scenario of external forcing, NSP area is larger, at the same global mean surface air temperature, in a warming climate than in a cooling climate. This hysteresis is visible more clearly for scenarios with higher concentration of greenhouse gases in the atmosphere in comparison to those in which this concentration is lower. Hysteresis details are not sensitive to the type of the prescribed continuation path which is used to return the climate to the preindustrial state. The multiple-valued dependence of S p on T g arises due to dependence of soil state in the regions of extra-tropical wetlands and near the contemporary NSP boundaries on sign of external climatic forcing. To study the dependence of permafrost hysteresis on amplitude and temporal scale of external forcing, additional model runs are performed. These runs are forced by idealised scenarios of atmospheric CO2 content varying, depending on run, with periods from 100 to 1,000 year and with different amplitudes. It is shown that the above-mentioned hysteresis is related to the impact of phase transitions of soil water on apparent inertia of the system as well as to the impact of soil state on atmospheric hydrological cycle and radiation transfer in the atmosphere.

Eliseev, Alexey V.; Demchenko, Pavel F.; Arzhanov, Maxim M.; Mokhov, Igor I.

2014-03-01

393

Loop Heat Pipes and Capillary Pumped Loops: An Applications Perspective  

NASA Technical Reports Server (NTRS)

Capillary pumped loops (CPLS) and loop heat pipes (LHPS) are versatile two-phase heat transfer devices which have recently gained increasing acceptance in space applications. Both systems work based on the same principles and have very similar designs. Nevertheless, some differences exist in the construction of the evaporator and the hydro-accumulator, and these differences lead to very distinct operating characteristics for each loop. This paper presents comparisons of the two loops from an applications perspective, and addresses their impact on spacecraft design, integration, and test. Some technical challenges and issues for both loops are also addressed.

Butler, Dan; Ku, Jentung; Swanson, Theodore; Obenschain, Arthur F. (Technical Monitor)

2001-01-01

394

Calibration of circular loop antennas  

Microsoft Academic Search

The calibration of a measuring loop antenna means assigning an antenna factor K for each frequency in the entire measurement band. Such a loop antenna factor can be found either by calculating the impedances of the loop, or by using a well-defined standard magnetic field of a transmitting antenna. For both methods, it is necessary to obtain an accurate relation

Aydin Aykan

1998-01-01

395

Scanning Polyhedra with DO Loops  

Microsoft Academic Search

Supercompilers perform complex program transformations which often result in new loop bounds. This paper shows that, under the usual assumptions in automatic parallelization, most transformations on loop nests can be expressed as affine transformations on integer sets de ned by polyhedra and that the new loop bounds can be computed with algorithms using Fourier's pairwise elimination method although it is

Corinne Ancourt; François Irigoin

1991-01-01

396

Adsorption hysteresis of nitrogen and argon in pore networks and characterization of novel micro- and mesoporous silicas.  

PubMed

We report results of nitrogen and argon adsorption experiments performed at 77.4 and 87.3 K on novel micro/mesoporous silica materials with morphologically different networks of mesopores embedded into microporous matrixes: SE3030 silica with worm-like cylindrical channels of mode diameter of approximately 95 angstroms, KLE silica with cage-like spheroidal pores of ca. 140 angstroms, KLE/IL silica with spheroidal pores of approximately 140 angstroms connected by cylindrical channels of approximately 26 angstroms, and, also for a comparison, on Vycor glass with a disordered network of pores of mode diameter of approximately 70 angstroms. We show that the type of hysteresis loop formed by adsorption/desorption isotherms is determined by different mechanisms of condensation and evaporation and depends upon the shape and size of pores. We demonstrate that adsorption experiments performed with different adsorptives allow for detecting and separating the effects of pore blocking/percolation and cavitation in the course of evaporation. The results confirm that cavitation-controlled evaporation occurs in ink-bottle pores with the neck size smaller than a certain critical value. In this case, the pressure of evaporation does not depend upon the neck size. In pores with larger necks, percolation-controlled evaporation occurs, as observed for nitrogen (at 77.4 K) and argon (at 87.3 K) on porous Vycor glass. We elaborate a novel hybrid nonlocal density functional theory (NLDFT) method for calculations of pore size distributions from adsorption isotherms in the entire range of micro- and mesopores. The NLDFT method, applied to the adsorption branch of the isotherm, takes into account the effect of delayed capillary condensation in pores of different geometries. The pore size data obtained by the NLDFT method for SE3030, KLE, and KLE/IL silicas agree with the data of SANS/SAXS techniques. PMID:16401128

Thommes, Matthias; Smarsly, Bernd; Groenewolt, Matthijs; Ravikovitch, Peter I; Neimark, Alexander V

2006-01-17

397

The Cinderella Loop Project  

NASA Astrophysics Data System (ADS)

On 1999 Nov 6 at 02:30 UT, a solar loop (dubbed Cinderella) on the northeast limb was simultaneously observed by TRACE, EIT on SOHO, and SXT on Yohkoh. This project investigates differences among the data sets from the three instruments. For example, EIT and TRACE have nearly identical temperature responses, but does the high resolution TRACE imager (0.5 arcsec pixels) produce results that match those from the lower resolution EIT imager (2.6 arcsec pixels)? Furthermore, EIT and SXT have similar spatial resolutions, but their temperature responses are much farther apart. Do these two instruments observe the same structures within the loop, and if so, how do their temperature and emissions measures compare? What are the effects of background subtraction on all three data sets? This presentation will address these questions. Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

O'Connor, J.; Coyle, T.; Douglass, J.; Schmelz, J. T.

2004-05-01

398

Getting Your Loops Straight  

NSDL National Science Digital Library

This article introduces a special issue on the study of biochemical signaling pathways. Complicated biochemical signaling pathways regulate the function of living cells. Such regulatory networks often have â??downstreamâ? components that provide input to components that act earlier in a pathway, creating feedback loops. These feedback loops have the potential to greatly alter the properties of a pathway and how it responds to stimuli. To fully understand these regulatory systems and exploit their vast potential as targets of therapeutic strategies, we need quantitative information on the flow of signals through a pathway and on the timing and location of signaling events within cells. The papers assembled in this special issue and in the companion issue of Science Signaling highlight recent progress in tackling these challenges.

L. Bryan Ray (AAAS; )

2008-10-17

399

Chemical Looping Combustion Kinetics  

SciTech Connect

One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).

Edward Eyring; Gabor Konya

2009-03-31

400

Cosmic string loop microlensing  

NASA Astrophysics Data System (ADS)

Cosmic superstring loops within the galaxy microlens background point sources lying close to the observer-string line of sight. For suitable alignments, multiple paths coexist and the (achromatic) flux enhancement is a factor of two. We explore this unique type of lensing by numerically solving for geodesics that extend from source to observer as they pass near an oscillating string. We characterize the duration of the flux doubling and the scale of the image splitting. We probe and confirm the existence of a variety of fundamental effects predicted from previous analyses of the static infinite straight string: the deficit angle, the Kaiser-Stebbins effect, and the scale of the impact parameter required to produce microlensing. Our quantitative results for dynamical loops vary by O(1) factors with respect to estimates based on infinite straight strings for a given impact parameter. A number of new features are identified in the computed microlensing solutions. Our results suggest that optical microlensing can offer a new and potentially powerful methodology for searches for superstring loop relics of the inflationary era.

Bloomfield, Jolyon K.; Chernoff, David F.

2014-06-01

401

Loops of Jupiter  

NASA Astrophysics Data System (ADS)

Professor Antoni Opolski was actively interested in astronomy after his retirement in 1983. He especially liked to study the works of the famous astronomer Copernicus getting inspiration for his own work. Opolski started his work on planetary loops in 2011 continuing it to the end of 2012 . During this period calculations, drawings, tables, and basic descriptions of all the planets of the Solar System were created with the use of a piece of paper and a pencil only. In 2011 Antoni Opolski asked us to help him in editing the manuscript and preparing it for publication. We have been honored having the opportunity to work on articles on planetary loops with Antoni Opolski in his house for several months. In the middle of 2012 the detailed material on Jupiter was ready. However, professor Opolski improved the article by smoothing the text and preparing new, better drawings. Finally the article ''Loops of Jupiter'', written by the 99- year old astronomer, was published in the year of his 100th birthday.

Opolski, Antoni

2014-12-01

402

Experimental investigation on the hysteresis phenomenon and the photostrictive effect of PLZT with coupled multi-physics fields  

NASA Astrophysics Data System (ADS)

Lead lanthanum zirconate (PLZT) ceramic has been widely studied as an opto-electromechanical actuator activated by ultraviolet light for active vibration control of various structures. However, the slow response time of photodeformation and the hysteresis phenomenon between the photovoltage and photo-induced deformation greatly affect the performance of PLZT as an actuator. The primary purposes of this article are to provide a comprehensive analysis on the hysteresis phenomenon and seek the reason of the hysteresis phenomenon with the experimental method. To this end, this study proposed the hysteresis phenomenon by photostrictive static experiments and investigated the possible influence factors on the hysteresis phenomenon through a series of experiments. The experimental results indicate that the temperature elevation of PLZT ceramic subjected to light illumination plays a significant role in the hysteresis phenomenon. Therefore, reducing the temperature rise of PLZT ceramic exposed to ultraviolet light is an effective means to eliminate the hysteresis phenomenon and improve the respond speed of photo-induced deformation.

Huang, J. H.; Wang, X. J.; Cheng, W. X.; Wang, J.

2015-04-01

403

Jorge G. Zornberg, Ph.D., P.E. IGS Vice-President  

E-print Network

Jorge G. Zornberg, Ph.D., P.E. IGS Vice-President The University of Texas at Austin, USA tel: +1://www.ce.utexas.edu/prof/zornberg/ Caro collega IGS, In qualitá di socio dell'IGS presto riceverai un invito a votare per la tornata elettorale 2010 dell'IGS. Vorrei incoraggiarTi a votare e spero che potrai considerare la mia candidatura

Zornberg, Jorge G.

404

Jorge G. Zornberg, Ph.D., P.E. IGS Vice-President  

E-print Network

Jorge G. Zornberg, Ph.D., P.E. IGS Vice-President The University of Texas at Austin, USA tel: +1://www.ce.utexas.edu/prof/zornberg/ Estimado colega de la IGS, Como miembro de la IGS, Usted recibirá en breve una invitación personal para votar en las elecciones de la IGS para 2010. Me gustaría invitarlo a que se tome su tiempo para votar, y

Zornberg, Jorge G.

405

A Commodity's Reputation-Based Trust Model of P2P E-Commerce Systems  

Microsoft Academic Search

In peer-to-peer (P2P) e-commerce systems, the trust mechanisms already proposed always replaced commodity's reputation with peer's reputation, so some peers often try to keep a relatively high peer's trust value while making their profit of doing some dishonest transactions. So, presented CRBT model (commodity's reputation-based trust model)-a novel trust mechanism. By introducing commodity's short-term reputation, commodity's accumulated reputation, peer's short-term

Fengyuan Zhu; Guangming Yang; Zhenhuan Tan

2010-01-01

406

P e d r o R os a s DYNAMIC INFLUENCES OF WIND  

E-print Network

P e d r o R os a s DYNAMIC INFLUENCES OF WIND POWER ON THE POWER SYSTEM P h D t h e s is S e c t i-91184-16-9 #12;DYNAMIC INFLUENCES OF WIND POWER ON THE POWER SYSTEM By Pedro Rosas Thesis submitted to Ørsted;DYNAMIC INFLUENCES OF WIND POWER ON THE POWER SYSTEM Pedro André Carvalho Rosas Risø National Laboratory

407

Coupled dual loop absorption heat pump  

DOEpatents

A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

Sarkisian, Paul H. (Watertown, MA); Reimann, Robert C. (Lafayette, NY); Biermann, Wendell J. (Fayetteville, NY)

1985-01-01

408

Fast-response single-inductor dual-output hysteresis-current-controlled DC–DC buck converter  

Microsoft Academic Search

A fast-response single-inductor dual-output hysteresis-current-controlled DC–DC buck is proposed for enhancing the transient\\u000a characteristics of switching DC–DC converters and fabricated with TSMC 0.35 ?m DPQM CMOS processes. By adopting a hysteresis-current-controlled\\u000a DC–DC buck converter, it is demonstrated that the hysteresis-current-controlled technique have improved dynamic response of\\u000a load variations whether the load current is light or heavy. Fast-response structure achieves 5 ?s response

Jiann-Jong Chen; Bo-Han Hwang; Jui-Hsuan Hsu; Yuh-Shyan Hwang; Cheng-Chieh Yu

409

Surface aligned magnetic moments and hysteresis of an endohedral single-molecule magnet on a metal.  

PubMed

The interaction between the endohedral unit in the single-molecule magnet Dy_{2}ScN@C_{80} and a rhodium (111) substrate leads to alignment of the Dy 4f orbitals. The resulting orientation of the Dy_{2}ScN plane parallel to the surface is inferred from comparison of the angular anisotropy of x-ray absorption spectra and multiplet calculations in the corresponding ligand field. The x-ray magnetic circular dichroism is also angle dependent and signals strong magnetocrystalline anisotropy. This directly relates geometric and magnetic structure. Element specific magnetization curves from different coverages exhibit hysteresis at a sample temperature of ?4??K. From the measured hysteresis curves, we estimate the zero field remanence lifetime during x-ray exposure of a submonolayer to be about 30 seconds. PMID:25768775

Westerström, Rasmus; Uldry, Anne-Christine; Stania, Roland; Dreiser, Jan; Piamonteze, Cinthia; Muntwiler, Matthias; Matsui, Fumihiko; Rusponi, Stefano; Brune, Harald; Yang, Shangfeng; Popov, Alexey; Büchner, Bernd; Delley, Bernard; Greber, Thomas

2015-02-27

410

Surface Aligned Magnetic Moments and Hysteresis of an Endohedral Single-Molecule Magnet on a Metal  

NASA Astrophysics Data System (ADS)

The interaction between the endohedral unit in the single-molecule magnet Dy2ScN @C80 and a rhodium (111) substrate leads to alignment of the Dy 4 f orbitals. The resulting orientation of the Dy2ScN plane parallel to the surface is inferred from comparison of the angular anisotropy of x-ray absorption spectra and multiplet calculations in the corresponding ligand field. The x-ray magnetic circular dichroism is also angle dependent and signals strong magnetocrystalline anisotropy. This directly relates geometric and magnetic structure. Element specific magnetization curves from different coverages exhibit hysteresis at a sample temperature of ˜4 K . From the measured hysteresis curves, we estimate the zero field remanence lifetime during x-ray exposure of a submonolayer to be about 30 seconds.

Westerström, Rasmus; Uldry, Anne-Christine; Stania, Roland; Dreiser, Jan; Piamonteze, Cinthia; Muntwiler, Matthias; Matsui, Fumihiko; Rusponi, Stefano; Brune, Harald; Yang, Shangfeng; Popov, Alexey; Büchner, Bernd; Delley, Bernard; Greber, Thomas

2015-02-01

411

Density hysteresis of heavy water confined in a nanoporous silica matrix  

PubMed Central

A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We interpret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid–liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved. PMID:21746898

Zhang, Yang; Faraone, Antonio; Kamitakahara, William A.; Liu, Kao-Hsiang; Mou, Chung-Yuan; Leão, Juscelino B.; Chang, Sung; Chen, Sow-Hsin

2011-01-01

412

Theory of Sorption Hysteresis in Nanoporous Solids: I. Snap-Through Instabilities  

E-print Network

The sorption-desorption hysteresis observed in many nanoporous solids, at vapor pressures low enough for the the liquid (capillary) phase of the adsorbate to be absent, has long been vaguely attributed to changes in the nanopore structure, but no mathematically consistent explanation has been presented. The present work takes an analytical approach to account for discrete molecular forces in the nanopore fluid and proposes two related mechanisms that can explain the hysteresis at low vapor pressure without assuming any change in the nanopore structure. The first mechanism, presented in Part I, consists of a series of snap-through instabilities during the filling or emptying of non-uniform nanopores or nanoscale asperities. The instabilities are caused by non-uniqueness in the misfit disjoining pressures engendered by a difference between the nanopore width and an integer multiple of the thickness of a monomolecular adsorption layer. The second mechanism, presented in Part II, consists of molecular coalescence...

Bazant, Zdenek P

2011-01-01

413

Density hysteresis of heavy water confined in a nanoporous silica matrix  

SciTech Connect

A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We inter- pret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved.

Zhang, Yang [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Kamitakahara, William [ORNL; Liu, Kao-Hsiang [National Taiwan University; Mou, Chung-Yuan [National Taiwan University; Leao, Juscelino B [ORNL; Chang, Sung C [ORNL; Chen, Sow-hsin H [ORNL

2011-01-01

414

Experimental and Numerical Study of the Role of Disorder on Contact Angle Hysteresis  

NASA Astrophysics Data System (ADS)

Hysteretic behavior of the contact angle of a liquid on a solid is often ascribed to topographic or chemical heterogeneity of the surface. Recent experiments by Rolley and GuthmannootnotetextE. Rolley and C. Guthmann, Phys. Rev. Lett. 98, 166105 (2007). on liquid hydrogen on cesium suggest that both the hysteresis and the contact line dynamics might be explained in terms of the mesoscale structure of the cesium surface. We have investigated a room temperature system with similar wetting and structural properties, tetradecane on dodecanethiol-treated evaporated gold films, and compare the results with a model of the expected hysteresis due to the topographical heterogeneity as measured by AFM, and reported disorder in the thiol film.ootnotetextE. Delamarche, B. Michel, H. Kang and C.Gerber, Langmuir 10, 4103 (1994).

Sams, Angelina N.; Merten, Victoria E.; Pettersen, Michael S.

2012-02-01

415

Hysteresis mechanism and control in pentacene organic field-effect transistors with polymer dielectric  

NASA Astrophysics Data System (ADS)

Hysteresis mechanism of pentacene organic field-effect transistors (OFETs) with polyvinyl alcohol (PVA) and/or polymethyl methacrylate (PMMA) dielectrics is studied. Through analyzing the electrical characteristics of OFETs with various PVA/PMMA arrangements, it shows that charge, which is trapped in PVA bulk and at the interface of pentacene/PVA, is one of the origins of hysteresis. The results also show that memory window is proportional to both trap amount in PVA and charge density at the gate/PVA or PVA/pentacene interfaces. Hence, the controllable memory window of around 0 ˜ 10 V can be realized by controlling the thickness and combination of triple-layer polymer dielectrics.

Huang, Wei; Shi, Wei; Han, Shijiao; Yu, Junsheng

2013-05-01

416

An implicit method for the nonlinear modelling and simulation of piezoceramic actuators displaying hysteresis  

NASA Technical Reports Server (NTRS)

Experiments have shown that piezoceramic materials display a nonlinear relationship between the applied electric field and the actuation strain. This relationship also displays a substantial hysteresis upon reversal of the applied field. In this paper, piezoceramic actuator models are incorporated into the structural equations of motion to arrive at a set of nonlinear actively controlled structural equations of motion. A new implicit algorithm for determining the time history of the actively controlled structure is presented. The algorithm employs the trapezoidal rule for stepping the equations forward in time. The algorithm is compared to an explicit algorithm and is shown to provide greater numerical accuracy. In addition, the numerical stability and convergence characteristics are presented via example. The new algorithm displays convergence and stability properties that are comparable to the standard trapezoidal rule used for dynamic systems without hysteresis.

Leigh, Timothy D.; Zimmerman, David C.

1991-01-01

417

Precision beam pointing control with jitter attenuation by optical deflector exhibiting dynamic hysteresis in COIL  

NASA Astrophysics Data System (ADS)

Due to the existence of various disturbances during the lasing process of the chemical oxygen iodine laser (COIL), the optical beam pointing performance is severely degraded. In this paper, an adaptive control methodology is proposed for the precise pointing control of the optical beam with active beam jitter rejection using a giant magnetostrictive optical deflector (GMOD) which exhibits severe dynamic hysteresis nonlinearity. In particular, a least square support vector machine (LS-SVM) based fast compensator is employed to eliminate the dynamic hysteresis without the inverse model construction. Then an improved feedforward adaptive filter is developed to deal with jitter attenuation when the full-coherent reference signal is unavailable. To improve the stability and overall robustness of the controller, especially when a large initial bias exists, a PI controller is placed in parallel with the adaptive filter. Experimental results validate the precise pointing ability of the proposed control method.

Ma, Yan-Hua; Zhang, Zeng-Bao; Zhang, Zhi-Guo; Liu, Qin; He, Xin; Shi, Wen-Bo; Mao, Jian-Qin; Jin, Yu-Qi

2015-02-01

418

Simulation study of hysteresis in the gradient-flux relation in toroidal plasma turbulence  

NASA Astrophysics Data System (ADS)

Global nonlinear simulations with heat modulation are carried out to understand the turbulent transport mechanism in toroidal plasmas. Rapid propagation of the heat modulation and a hysteresis in the gradient-flux relation are found in the turbulent simulation of drift-interchange modes. A global mode is excited nonlinearly, and the nonlinear couplings with Reynolds stress take a finite temporal duration for self-consistent redistribution of the energy. The mode also has a seesaw effect: increase of the amplitude of the global mode at one position affects the turbulence at the other radial position not by inducing the radial flux by itself, but by absorbing the energy from microscopic modes. Successive excitations of microscopic modes cause the accelerated propagation of the flux change like turbulence spreading after the onset of modulation. Owing to these non-diffusive processes, the hysteresis appears in the gradient-flux relation, which is compared with experiments.

Kasuya, N.; Sugita, S.; Inagaki, S.; Itoh, K.; Yagi, M.; Itoh, S.-I.

2015-04-01

419

The Gulf Loop Current  

NSDL National Science Digital Library

Students conduct experiments and explore wind driven currents, determining patterns of current flow in a body of water. They participate in a relay where they blow a Styrofoam peanut or cotton ball across the classroom floor. They explore the motion of Styrofoam pieces that are floating in a clear pie pan of water simulating the Gulf Loop, and compare their pie pan model with a map of the currents. Students will map the trip of several different types of beach debris as it travels to the Texas coast.

Pam Stryker

2010-01-01

420

Capillary Pumped Loop Modeler  

NASA Technical Reports Server (NTRS)

Capillary Pumped Loop (CPL) Modeler computer program is amalgamation of software that mathematically models performance of CPL system and its environment. Two-phase heat-transport device capable of transferring heat loads efficiently over large distance with little temperature differential. Utilizes surface-tension forces established in fine-pore capillary wick to circulate working fluid, requiring no external pumpling power. Predicts steady-state or quasi-steady behavior of CPL embedded in spacecraft or other thermal environment. Also predicts location of liquid/vapor interface in each condenser. Written in VAX/VMS FORTAN 77.

Ku, Jentung; Itkin, Elliot; Schweickart, Russell B.; Ottenstein, Laura

1990-01-01

421

Closing the loop.  

PubMed

Closed-loop algorithms can be found in every aspect of everyday modern life. Automation and control are used constantly to provide safety and to improve quality of life. Closed-loop systems and algorithms can be found in home appliances, automobiles, aviation and more. Can one imagine nowadays driving a car without ABS, cruise control or even anti-sliding control? Similar principles of automation and control can be used in the management of diabetes mellitus (DM). The idea of an algorithmic/technological way to control glycaemia is not new and has been researched for more than four decades. However, recent improvements in both glucose-sensing technology and insulin delivery together with advanced control and systems engineering made this dream of an artificial pancreas possible. The artificial pancreas may be the next big step in the treatment of DM since the use of insulin analogues. An artificial pancreas can be described as internal or external devices that use continuous glucose measurements to automatically manage exogenous insulin delivery with or without other hormones in an attempt to restore glucose regulation in individuals with DM using a control algorithm. This device as described can be internal or external; can use different types of control algorithms with bi-hormonal or uni-hormonal design; and can utilise different ways to administer them. The different designs and implementations have transitioned recently from in silico simulations to clinical evaluation stage with practical applications in mind. This may mark the beginning of a new era in diabetes management with the introduction of semi-closed-loop systems that can prevent or minimise nocturnal hypoglycaemia, to hybrid systems that will manage blood glucose (BG) levels with minimal user intervention to finally fully automated systems that will take the user out of the loop. More and more clinical trials will be needed for the artificial pancreas to become a reality but initial encouraging results are proof that we are on the right track. We attempted to select recent publications that will present these current achievements in the quest for the artificial pancreas and that will inspire others to continue to progress this field of research. PMID:21323809

Dassau, E; Atlas, E; Phillip, M

2011-02-01

422

Two loop divergences studied with one loop constrained differential renormalization  

NASA Astrophysics Data System (ADS)

In the context of differential renormalization, using constrained differential renormalization rules at one-loop, we show how to obtain concrete results in two-loop calculations without making use of Ward identities. In order to do that, we obtain a list of integrals with overlapping divergences compatible with CDR that can be applied to various two-loop background field calculations. As an example, we obtain the two-loop coefficient of the beta function of QED, SuperQED and Yang-Mills theory.

Seijas, Cesar

2007-08-01

423

Hysteresis Modeling of the Porous Nitinol Delivery System, Designed and Fabricated By Sls Method  

NASA Astrophysics Data System (ADS)

At report, we presented a common design and theoretical modelling scheme for a porous scaffold from nitinol with a shape memory effect (SME), fabricated by the selective laser sintering (SLS) process. The operation of the SME fluidic MEMS involves such physical process as heat transfer, phase transformation with temperature hysteresis, stress-strain and electrical resistance variations accompanying the phase transformation. This model can be used for an estimation of drug delivery system (DDS) route during a porous volume changing.

Shishkovsky, I.

424

Hysteresis and metastability of Bose-Einstein-condensed clouds of atoms confined in ring potentials  

NASA Astrophysics Data System (ADS)

We consider a Bose-Einstein-condensed cloud of atoms which rotate in a toroidal or annular potential. Assuming one-dimensional motion, we evaluate the critical frequencies associated with the effect of hysteresis and the critical coupling for stability of the persistent currents. We perform these calculations using both the mean-field approximation and the method of numerical diagonalization of the many-body Hamiltonian which includes corrections due to the finiteness of the atom number.

Roussou, A.; Tsibidis, G. D.; Smyrnakis, J.; Magiropoulos, M.; Efremidis, Nikolaos K.; Jackson, A. D.; Kavoulakis, G. M.

2015-02-01

425

A level-set approach for simulations of flows with multiple moving contact lines with hysteresis  

Microsoft Academic Search

The level-set method of Sussman et al. [J. Comput. Phys. 148 (1999) 81] is extended such that flows with multiple moving contact lines can be simulated, accounting for inertia, a relation between contact-line speed and contact angle, slip and contact-line hysteresis. The convergence properties of the method are investigated, with particular attention on the resolution of the contact-line stress singularity.

Peter D. M. Spelt

2005-01-01

426

Global distribution of solid and aqueous sulfate aerosols: Effect of the hysteresis of particle phase transitions  

Microsoft Academic Search

The partitioning between solid and aqueous phases of tropospheric sulfate-ammonium particles is simulated with a global 3-D chemical transport model (CTM). The simulation explicitly accounts for the hysteresis of particle phase transitions by transporting aqueous sulfate and three solid sulfate forms (namely, ammonium sulfate, letovicite, and ammonium bisulfate). Composition-dependent deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) are based

Jun Wang; Andrew A. Hoffmann; Daniel J. Jacob; Scot T. Martin

2008-01-01

427

Global distribution of solid and aqueous sulfate aerosols: Effect of the hysteresis of particle phase transitions  

Microsoft Academic Search

(1) The partitioning between solid and aqueous phases of tropospheric sulfate-ammonium particles is simulated with a global 3-D chemical transport model (CTM). The simulation explicitly accounts for the hysteresis of particle phase transitions by transporting aqueous sulfate and three solid sulfate forms (namely, ammonium sulfate, letovicite, and ammonium bisulfate). Composition-dependent deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) are

Jun Wang; Andrew A. Hoffmann; Daniel J. Jacob; Scot T. Martin

2008-01-01

428

Model for the effect of tensile and compressive stress on ferromagnetic hysteresis  

NASA Astrophysics Data System (ADS)

A model is presented for the stress-dependent effective field, which when used in conjunction with the Jiles-Atherton theory, qualitatively accounts for (1) the change in slope and shape of the hysteresis curves with uniaxial stress and (2) the convexity of the curves depicting remanent and peak magnetization as a function of stress. Also, the model can produce the Villari reversal if parameters are selected appropriately.

Sablik, M. J.; Kwun, H.; Burkhardt, G. L.; Jiles, D. C.

1987-04-01

429

Temperature hysteresis of the change in the cholesteric pitch and surface anchoring in thin planar layers  

Microsoft Academic Search

Hysteresis of the temperature of jumps in the cholesteric pitch in planar layers of cholesteric liquid crystals (CLCs) has\\u000a been observed in the temperature dependence of the optical transmission spectra measured in a 4.8 m thick specimen of a 60% chiral racemic mixture of CE6. The temperature difference for the pitch jumps during heating and\\u000a cooling was equal to about

H. Zink; V. A. Belyakov

1997-01-01

430

Thermodynamic Analysis of Snowball Earth Hysteresis Experiment: Efficiency, Entropy Production, and Irreversibility  

Microsoft Academic Search

We present an extensive thermodynamic analysis of a hysteresis experiment\\u000aperformed on a simplified yet Earth-like climate model. We slowly vary the\\u000asolar constant by 20% around the present value and detect a substantial\\u000abistability: for a large range of values the realization of snowball (SB) or of\\u000awarm (W) climate conditions depend on the history of the system. Using

Klaus Fraedrich; Frank Lunkeit

2009-01-01

431

Hysteresis-Current-Controlled Buck Converter Suitable for Li-Ion Battery Charger  

Microsoft Academic Search

A new hysteresis-current-controlled (HCC) buck converter suitable for Li-ion battery charger is presented in this paper. The technique adopted in this charger is constant current\\/constant voltage dual mode, which is decided by the value of internal resistance of Li-ion battery. This technique will degrade the damage of Li-ion battery and improve the power efficiency of charger. The Li-ion battery charger

Fong-Cheng Yang; Chih-Chiang Chen; Jiann-Jong Chen; Yuh-Shyan Hwang; Wen-Ta Lee

2006-01-01

432

Incorporating core hysteresis properties in three-dimensional computations of transformer inrush current forces  

NASA Astrophysics Data System (ADS)

It is well known that transformer inrush currents depend upon the core properties, residual flux, switching instant, and the overall circuit parameters. Large transient inrush currents introduce abnormal electromagnetic forces which may destroy the transformer windings. This paper presents an approach through which core hysteresis may be incorporated in three-dimensional computations of transformer inrush current forces. Details of the approach, measurements, and simulations for a shell-type transformer are given in the paper.

Adly, A. A.; Hanafy, H. H.

2009-04-01

433

Magnetic processes in hysteresis motors equipped with melt-textured YBCO  

Microsoft Academic Search

Several hysteresis motors have been constructed with an output power up to 500 W at T=77 K. The rotors of these machines consist of melt-textured YBCO. In this work, the authors present detailed investigations on the magnetic processes in these rotors. Spheres were cut from melt-textured YBCO and investigated by rotating in vector-VSM. From these measurements, torque moments on the

T. Habisreuther; T. Strasser; W. Gawalek; P. Gornert; K. V. Ilushin; L. K. Kovalev

1997-01-01

434

Numerical study for hysteresis phenomena of shock wave reflection in overexpanded axisymmetric supersonic jet  

Microsoft Academic Search

When the high-pressure gas is exhausted to the vacuum chamber from the supersonic nozzle, the overexpanded supersonic jet\\u000a is formed at specific condition. In two-dimensional supersonic jet, furthermore, it is known that the hysteresis phenomena\\u000a for the reflection type of shock wave in the flow field is occurred under the quasi-steady flow and for instance, the transitional\\u000a pressure ratio between

Tsuyoshi Yasunobu; Ken Matsuoka; Hideo Kashimura; Shigeru Matsuo; Toshiaki Setoguchi

2006-01-01

435

Analytical modeling of the hysteresis phenomenon in guinea pig ventricular myocytes  

Microsoft Academic Search

In the present study, we have demonstrated hysteresis phenomena in the excitability of single, enzymatically dissociated guinea pig ventricular myocytes. Membrane potentials were recorded with patch pipettes in the whole-cell current clamp configuration. Repetitive stimulation with depolarizing current pulses of constant cycle length and duration but varying strength led to predictable excitation (1:l) and non-excitation (1:0) patterns depending on current

Paco Lorente; Carmen Delgado; Mario Delmar; Jose Jalife

1992-01-01

436

A Sub10- Digitally Controlled Oscillator Based on Hysteresis Delay Cell Topologies for WBAN Applications  

Microsoft Academic Search

This brief presents an all digitally controlled oscillator (DCO) design with two newly proposed hysteresis delay cells (HDCs) for wireless body area network applications. According to circuit topologies, the two HDCs are defined as on-off and cascaded HDCs that provide various propagation delay values. These HDCs form a simple oscillator structure based on a power-of-2 delay stage DCO (P2-DCO) architecture.

Shu-Yu Hsu; Jui-Yuan Yu; Chen-Yi Lee

2010-01-01

437

Kinematics of Electrons in The Volume of a Planar Vacuum Diode in Regime of Saturation. Parameters of Hysteresis  

E-print Network

The kinematics laws of electrons motion in the volume of a planar vacuum diode running in regime of current saturation are used. The characteristics of diode hysteresis in the conditions of S-figurative instability are got and analyzed.

Stoyanov, Dimitar G

2015-01-01

438

Kinematics of Electrons in The Volume of a Planar Vacuum Diode in Regime of Saturation. Parameters of Hysteresis  

E-print Network

The kinematics laws of electrons motion in the volume of a planar vacuum diode running in regime of current saturation are used. The characteristics of diode hysteresis in the conditions of S-figurative instability are got and analyzed.

Dimitar G. Stoyanov

2014-12-19

439

A modeling approach to represent hysteresis in capillary pressure-saturation relationship based on fluid connectivity in void space  

E-print Network

A modeling approach to represent hysteresis in capillary pressure- saturation relationship based presents a new model for description of hysteretic constitutive relationships between capillary pressure and saturation under capillary-dominated multiphase flow conditions in porous media. Hysteretic relationships

Zhou, Quanlin

440

Observation of optical hysteresis in an all-optical passive ring cavity  

NASA Astrophysics Data System (ADS)

The first observation of dispersive optical hysteresis in an all optical passive uni-directional ring cavity system is reported. Ammonia gas is used as the non-linear medium for which a number of vibrational-rotational transitions are in near coincidence with the step tunable emission from a TEA CO2 laser. Pronounced instabilities and optical hysteresis are found to occur over a gas pressure range commensurate with that for self-focussing. A grating tunable hybrid TEA CO2 laser with amplifier, operating on a single mode, with a gain switched pulse duration of approximately 10 nsec was used. The temporal features of the cavity signal was sensitive to gas pressure. Outside the pressure range for instabilities (and self focussing) the ring signal exhibited a smooth temporal form similar to that of the incident signal. Cavity blocking and cavity misalignment checks unambiguously identified these nonlinear effects to be due to cavity feedback. Hysteresis associated with optical bistability is clearly evident for an NH3 pressure of 10 torr.

Harrison, R. G.; Emshary, C.; Al-Saidi, I.

1984-01-01

441

Purification and characterization of a thermal hysteresis protein from a plant, the bittersweet nightshade Solanum dulcamara.  

PubMed

Thermal hysteresis proteins (THPs), which depress the freezing point of water below the melting point (producing a characteristic thermal hysteresis), are well known for their antifreeze activity in both fish and terrestrial arthropods, but have only recently been identified in plants. This study describes the purification of a THP from winter-collected bittersweet nightshade, Solanum dulcamara, using ion exchange and preparative 'free flow' isoelectric focusing. The THP has a molecular mass of 67 kDa (considerably larger than those of animal THPs), and an unusually high glycine component (23.7 mol%). Treatments of the THP with periodate or borate caused inactivation, suggesting the presence of carbohydrate. More specific treatments directed at galactose (beta-galactosidase or Abrus precatorius lectin) also resulted in inactivation, indicating that galactose is present. A thermal hysteresis activity versus THP concentration curve showed that the specific activity of the S. dulcamara THP is lower than that of any known animal THP. The functional significance of this low activity is discussed. PMID:8186242

Duman, J G

1994-05-18

442

Modeling concentration-dependent sorption-desorption hysteresis of atrazine in a loam soil.  

PubMed

Nonequilibrium sorption plays an active role in the transport of organic contaminants in soil. We applied a two-stage, one-rate model (2S1R) and a new, nonlinear variant (2S1RN) of this model to examine the effects of wastewater irrigation on the sorption kinetics of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in soil. The models were applied to previously published sorption-desorption data sets, which showed pronounced deviations between sorption curves and desorption curves (sorption-desorption hysteresis). Moreover, the slopes of the desorption curves decreased with decreasing concentration. Different treatments had been used, and two experimental time steps (2 and 14 d) were used. Treatments considered were lipid removal, fulvic and humic acid removal, and untreated soil. The 2S1R model was unable to reproduce the observed type of hysteresis, but the 2S1RN model, which assumes that the sorption-desorption process follows a power function relationship, was able to reproduce the observed type of hysteresis. Visually, applying the new model improved the model fits in all test cases. Statistically, as tested by an extra sum of squares analysis, the new model performed significantly better in 50% of all test cases. According to an example simulation, the choice of the sorption model has a considerable impact on the prediction of atrazine transport in soil. PMID:21520761

Anagu, Ihuaku; Ingwersen, Joachim; Drori, Yaron; Chefetz, Benny; Streck, Thilo

2011-01-01

443

Observations of hysteresis in solar cycle variations among seven solar activity indicators  

NASA Technical Reports Server (NTRS)

We show that smoothed time series of 7 indices of solar activity exhibit significant solar cycle dependent differences in their relative variations during the past 20 years. In some cases these observed hysteresis patterns start to repeat over more than one solar cycle, giving evidence that this is a normal feature of solar variability. Among the indices we study, we find that the hysteresis effects are approximately simple phase shifts, and we quantify these phase shifts in terms of lag times behind the leading index, the International Sunspot Number. Our measured lag times range from less than one month to greater than four months and can be much larger than lag times estimated from short-term variations of these same activity indices during the emergence and decay of major active regions. We argue that hysteresis represents a real delay in the onset and decline of solar activity and is an important clue in the search for physical processes responsible for changing solar emission at various wavelengths.

Bachmann, Kurt T.; White, Oran R.

1994-01-01

444

Hysteresis properties of ordinary chondrites and implications for their thermal history  

NASA Astrophysics Data System (ADS)

We present a large dataset of magnetic hysteresis properties of ordinary chondrite falls. We show that hysteresis properties are distinctive of individual meteorites while homogeneous among meteorite subsamples. Except for the most primitive chondrites, these properties can be explained by a mixture of multidomain kamacite and tetrataenite (both in the cloudy zone and as larger grains in plessite and in the rim of zoned taenite). Kamacite dominates the induced magnetism whereas tetrataenite dominates the remanent magnetism, in agreement with previous microscopic magnetic observations. Type 5 and 6 chondrites have higher tetrataenite content than type 4 chondrites, suggesting they have lower cooling rates at least in the 650-450 °C interval, consistent with an onion-shell model. In equilibrated chondrites, shock-related transient heating events above ~500 °C result in the disordering of tetrataenite and associated drastic change in magnetic properties. As a good indicator of the amount of tetrataenite, hysteresis properties are a very sensitive proxy of the thermal history of ordinary chondrites, revealing low cooling rates during thermal metamorphism, and high cooling rates following shock reheating or excavation after thermal metamorphism.

Gattacceca, J.; Suavet, C. R.; Rochette, P.; Weiss, B. P.; Winklhofer, M.; Uehara, M.; Friedrich, J. M.

2013-12-01

445

A reduced-order model from high-dimensional frictional hysteresis.  

PubMed

Hysteresis in material behaviour includes both signum nonlinearities as well as high dimensionality. Available models for component-level hysteretic behaviour are empirical. Here, we derive a low-order model for rate-independent hysteresis from a high-dimensional massless frictional system. The original system, being given in terms of signs of velocities, is first solved incrementally using a linear complementarity problem formulation. From this numerical solution, to develop a reduced-order model, basis vectors are chosen using the singular value decomposition. The slip direction in generalized coordinates is identified as the minimizer of a dissipation-related function. That function includes terms for frictional dissipation through signum nonlinearities at many friction sites. Luckily, it allows a convenient analytical approximation. Upon solution of the approximated minimization problem, the slip direction is found. A final evolution equation for a few states is then obtained that gives a good match with the full solution. The model obtained here may lead to new insights into hysteresis as well as better empirical modelling thereof. PMID:24910522

Biswas, Saurabh; Chatterjee, Anindya

2014-06-01

446

Effect of Hysteresis on Measurements of Thin-Film Cell Performance  

SciTech Connect

Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (Voc), up to 10 mV, and smaller short-circuit current density (Jsc), by up to 2 mA/cm2, relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be as large as 3%. When Cu is not added, hysteresis in both Voc and Jsc is negligible however Pmax hysteresis is considerably greater. This behavior corroborates observed changes in depletion width, Wd, derived from capacitance (C) vs voltage (V) scans. Measured values of Wd are always smaller in reverse-to-forward voltage scans, and conversely, larger in the forward-to-reverse voltage direction. Transient ion drift (TID) measurements performed on Cu-containing cells do not show ionic behavior suggesting that capacitance transients are more likely due to electronic capture-emission processes. J-V curve simulation using Pspice shows that increased transient capacitance during light-soak stress at 100 degrees C correlates with increased space-charge recombination. Voltage-dependent collection however was not observed to increase with stress in these cells.

Albin, D.; del Cueto, J.

2011-03-01

447

Hysteresis effects in a motor task with cotton-top tamarins (Sanguinus oedipus).  

PubMed

The way human adults grasp an object is influenced by their recent history of motor actions. Previously executed grasps are often more likely to reoccur on subsequent grasps. This type of hysteresis effect has been incorporated into cognitive models of motor planning, suggesting that when planning movements, individuals tend to reuse recently used plans rather than generating new plans from scratch. To the best of our knowledge, the phylogenetic roots of this phenomenon have not been investigated. Here, the authors asked whether 6 cotton-top tamarin monkeys (Saguinus oedipus) would demonstrate a hysteresis effect on a reaching task. The authors tested the monkeys by placing marshmallow pieces within grasping distance of a hole through which the monkeys could reach. On subsequent trials, the marshmallow position changed such that it progressed in an arc in either a clockwise or counterclockwise direction. The authors asked whether the transition point in right- versus left-handed reaches would differ depending on the direction of the progression. The data supported this hysteresis prediction. The outcome provides additional support for the notion that human motor planning strategies may have a lengthy evolutionary history. PMID:19594287

Weiss, Daniel J; Wark, Jason

2009-07-01

448

a Thermal Conduction Switch Based on Low Hysteresis Nitife Shape Memory Alloy Helical Springs  

NASA Astrophysics Data System (ADS)

Shape memory alloy (SMA) actuators possess an inherent property of sensing a change in temperature and delivering significant force against external loads through a shape change resulting from a temperature-induced phase transformation. The utilization of a reversible trigonal (R-phase) to cubic phase transformation in NiTiFe SMAs allows for this strain recovery to occur with reduced hysteresis between the forward and reverse transformations. However, the magnitude of the strain recovery associated with the R-phase transformation is lower than that of the monoclinic to cubic phase transformation. The use of helical springs can compensate for this design constraint as they produce significant stroke when compared to straight elements such as thin strips and wires. This work reports on the development and implementation of NiTiFe helical springs in a low-hysteresis thermal conduction switch for advanced spaceport applications associated with NASA's requirements for future lunar and Mars missions. Such a low-hysteresis thermal conduction switch can provide on-demand heat transfer between two reservoirs at different temperatures.

Krishnan, V. B.; Bewerse, C.; Notardonato, W. U.; Vaidyanathan, R.

2008-03-01

449

Hysteresis force loss and damping properties in a practical magnet superconductor maglev test vehicle  

NASA Astrophysics Data System (ADS)

In order to investigate the feasible application of a permanent magnet-high-temperature superconductor (PM-HTS) interaction maglev system to a maglev train or a space vehicle launcher, we have constructed a demonstration maglev test vehicle. The force dissipation and damping of the maglev vehicle against external disturbances are studied in a wide range of amplitudes and frequencies by using a sine vibration testing set-up. The dynamic levitation force shows a typical hysteresis behavior, and the force loss is regarded as the hysteresis loss, which is believed to be due to flux motions in superconductors. In this study, we find that the hysteresis loss has weak frequency dependence at small amplitudes and that the dependence increases as the amplitude grows. To analyze the damping properties of the maglev vehicle at different field cooling (FC) conditions, we also employ a transient vibration testing technique. The maglev vehicle shows a very weak damping behavior, and the damping is almost unaffected by the trapped flux of the HTSs in different FC conditions, which is believed to be attributed to the strong pinning in melt-textured HTSs.

Yang, Wenjiang; Liu, Yu; Wen, Zheng; Chen, Xiaodong; Duan, Yi

2008-01-01

450

Nonequilibrium hysteresis and Wien effect water dissociation at a bipolar membrane  

NASA Astrophysics Data System (ADS)

As in electrochemical cyclic voltammetry, time-periodic reverse voltage bias across a bipolar membrane is shown to exhibit hysteresis due to transient effects. This is due to the incomplete depletion of mobile ions, at the junction between the membranes, within two adjoining polarized layers; the layer thickness depends on the applied voltage and the surface charge densities. Experiments show that the hysteresis consists of an Ohmic linear rise in the total current with respect to the voltage, followed by a decay of the current. A limiting current is established for a long period when all the mobile ions are depleted from the polarized layer. If the resulting high field within the two polarized layers is sufficiently large, water dissociation occurs to produce proton and hydroxyl traveling wave fronts which contribute to another large jump in the current. We use numerical simulation and asymptotic analysis to interpret the experimental results and to estimate the amplitude of the transient hysteresis and the water-dissociation current.

Conroy, D. T.; Craster, R. V.; Matar, O. K.; Cheng, L.-J.; Chang, H.-C.

2012-11-01

451

Changes in Wetting Hysteresis During Bioremediation: Changes in fluid flow behavior monitored with low-frequency seismic attenuation  

NASA Astrophysics Data System (ADS)

We observed significant reduction in wetting hysteresis with time while a diesel-contaminated quartz crystal was dipped in and out of an oil-reducing bacteria solution. This wetting hysteresis is significantly greater than the wetting hysteresis when the diesel-contaminated quartz crystal is dipped in and out of (1) water, (2) diesel and (3) the bacterial food solution that does not contain bacteria. The reduction in wetting hysteresis of the bacteria solution on the quartz surface results from a reduction in the advancing contact angle formed at the air-liquid-quartz contact with time; the receding contact angle remains the same with time. Our results suggest that the bacteria solution moves across the quartz surface with less resistance after bioremediation has begun. These results imply that bioremediation may influence fluid flow behavior with time. For many fluid-solid systems there is a difference between the contact angle while a contact line advances and recedes across a solid surface; this difference is known as wetting hysteresis. Changes in wetting hysteresis can occur from changes in surface tension or the surface topography. Low contact angle values indicate that the liquid spreads or wets well, while high values indicate poor wetting or non-wetting. Contact angles are estimated in the lab by measuring the weight of the meniscus formed at the air-liquid-quartz interface and by knowing the fluid surface tension. In the lab, we have been able to use low-frequency seismic attenuation data to detect changes in the wetting characteristics of glass plates and of Berea sandstone. The accepted seismic attenuation mechanism is related to the loss of seismic energy due to the hysteresis of meniscus movement (wetting hysteresis) when a pore containing two fluids is stressed at very low frequencies (< 10 Hz). When fluid-fluid-solid systems that exhibit wettability hysteresis are stressed at low frequencies, we observe seismic attenuation, whereas in a system that does not exhibit wettability hysteresis we do not. From our wettability hysteresis results, we conclude that we may be able to monitor bioremediation progress using seismic attenuation data. We are measuring low-frequency seismic attenuation in the lab while flowing bacteria solution through Berea sandstone and we are testing this application in the field.

Wempe, W.; Spetzler, H.; Kittleson, C.; Pursley, J.

2003-12-01

452

Wilson loops as precursors  

SciTech Connect

There is substantial evidence that string theory on AdS{sub 5}xS{sub 5} is a holographic theory in which the number of degrees of freedom scales as the area of the boundary in Planck units. Precisely how the theory can describe bulk physics using only surface degrees of freedom is not well understood. A particularly paradoxical situation involves an event deep in the interior of the bulk space. The event must be recorded in the (Schroedinger picture) state vector of the boundary theory long before a signal, such as a gravitational wave, can propagate from the event to the boundary. In a previous paper with Polchinski, we argued that the ''precursor'' operators which carry information stored in the wave during the time when it vanishes in a neighborhood of the boundary are necessarily non-local. In this paper we argue that the precursors cannot be products of local gauge invariant operators such as the energy momentum tensor. In fact gauge theories have a class of intrinsically non-local operators which cannot be built from local gauge invariant objects. These are the Wilson loops. We show that the precursors can be identified with Wilson loops whose spatial size is dictated by the UV-IR connection. (c) 2000 The American Physical Society.

Susskind, Leonard [Department of Physics, Stanford University, Stanford, California 94305-4060 (United States)] [Department of Physics, Stanford University, Stanford, California 94305-4060 (United States); Toumbas, Nicolaos [Department of Physics, Stanford University, Stanford, California 94305-4060 (United States)] [Department of Physics, Stanford University, Stanford, California 94305-4060 (United States)

2000-02-15

453

Wilson Loops as Precursors  

E-print Network

There is substantial evidence that string theory on AdS_5 x S_5 is a holographic theory in which the number of degrees of freedom scales as the area of the boundary in Planck units. Precisely how the theory can describe bulk physics using only surface degrees of freedom is not well understood. A particularly paradoxical situation involves an event deep in the interior of the bulk space. The event must be recorded in the (Schroedinger Picture) state vector of the boundary theory long before a signal, such as a gravitational wave, can propagate from the event to the boundary. In a previous paper with Polchinski, we argued that the "precursor" operators which carry information stored in the wave during the time when it vanishes in a neighborhood of the boundary are necessarily non-local. In this paper we argue that the precursors cannot be products of local gauge invariant operators such as the energy momentum tensor. In fact gauge theories have a class of intrinsically non-local operators which cannot be built from local gauge invariant objects. These are the Wilson loops. We show that the precursors can be identified with Wilson loops whose spatial size is dictated by the UV-IR connection.

Leonard Susskind; Nicolaos Toumbas

2000-03-17

454

Ekpyrotic loop quantum cosmology  

SciTech Connect

We consider the ekpyrotic paradigm in the context of loop quantum cosmology. In loop quantum cosmology the classical big-bang singularity is resolved due to quantum gravity effects, and so the contracting ekpyrotic branch of the universe and its later expanding phase are connected by a smooth bounce. Thus, it is possible to explicitly determine the evolution of scalar perturbations, from the contracting ekpyrotic phase through the bounce and to the post-bounce expanding epoch. The possibilities of having either one or two scalar fields have been suggested for the ekpyrotic universe, and both cases will be considered here. In the case of a single scalar field, the constant mode of the curvature perturbations after the bounce is found to have a blue spectrum. On the other hand, for the two scalar field ekpyrotic model where scale-invariant entropy perturbations source additional terms in the curvature perturbations, the power spectrum in the post-bounce expanding cosmology is shown to be nearly scale-invariant and so agrees with observations.

Wilson-Ewing, Edward, E-mail: wilson-ewing@phys.lsu.edu [Department of Astronomy and Physics, Louisiana State University, Baton Rouge, 70803 (United States)

2013-08-01

455

Accelerating the loop expansion  

SciTech Connect

This thesis introduces a new non-perturbative technique into quantum field theory. To illustrate the method, I analyze the much-studied phi/sup 4/ theory in two dimensions. As a prelude, I first show that the Hartree approximation is easy to obtain from the calculation of the one-loop effective potential by a simple modification of the propagator that does not affect the perturbative renormalization procedure. A further modification then susggests itself, which has the same nice property, and which automatically yields a convex effective potential. I then show that both of these modifications extend naturally to higher orders in the derivative expansion of the effective action and to higher orders in the loop-expansion. The net effect is to re-sum the perturbation series for the effective action as a systematic ''accelerated'' non-perturbative expansion. Each term in the accelerated expansion corresponds to an infinite number of terms in the original series. Each term can be computed explicitly, albeit numerically. Many numerical graphs of the various approximations to the first two terms in the derivative expansion are given. I discuss the reliability of the results and the problem of spontaneous symmetry-breaking, as well as some potential applications to more interesting field theories. 40 refs.

Ingermanson, R.

1986-07-29

456

The double loop mattress suture  

PubMed Central

An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p ? 0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p ? 0.001). Wound gapping is equal, and wound eversion appears significantly improved (p ? 0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

2014-01-01

457

Number of cosmic string loops  

NASA Astrophysics Data System (ADS)

Using recent simulation results, we provide the mass and speed spectrum of cosmic string loops. This is the quantity of primary interest for many phenomenological signatures of cosmic strings, and it can be accurately predicted using recently acquired detailed knowledge of the loop production function. We emphasize that gravitational smoothing of long strings plays a negligible role in determining the total number of existing loops. We derive a bound on the string tension imposed by recent constraints on the stochastic gravitational wave background from pulsar timing arrays, finding G? ?2.8×10-9. We also provide a derivation of the Boltzmann equation for cosmic string loops in the language of differential forms.

Blanco-Pillado, Jose J.; Olum, Ken D.; Shlaer, Benjamin

2014-01-01

458

Long-term soil moisture variability from a new P-E water budget method  

NASA Astrophysics Data System (ADS)

Basin-scale soil moisture is traditionally estimated using either land-surface model forced by observed meteorological variables or atmospheric moisture convergence from atmospheric analysis and observed runoff. Interannual variability from such methods suffer from major uncertainties due to the sensitivity to small imperfections in the land-surface model or the atmospheric analysis. Here we introduce a novel P-E method in estimating basin-scale soil moisture, or more precisely apparent land water storage (AWS). The key input variables are observed precipitation and runoff, and reconstructed evaporation. We show the results for the tropics using the example of the Amazon basin. The seasonal cycle of diagnosed soil moisture over the Amazon is about 200mm, compares favorably with satellite estimate from the GRACE mission, thus lending confidence both in this method and the usefulness of space gravity based large-scale soil moisture estimate. This is about twice as large as estimates from several traditional methods, suggesting that current models tend to under estimate the soil moisture variability. One of the advantage of the P-E method is to retrive long-term variability of the basin-scale soil moisture (including interannual and decadal time scales), which can provide valuable information to understand climate variability and to predict future climate condition. However, validation on reconstructed evaporation is very difficult due to lack of observation. The interannual variability in AWS in the Amazon basin is about 150mm, also consistent with GRACE data, but much larger than model results. We also apply this P-E method to the midlatitude Mississippi basin and discuss the impact of major 20th century droughts such as the dust bowl period on the long-term soil moisture variability. The results suggest the existence of soil moisture memories on decadal time scales, significantly longer than typically assumed seasonal timescales.

Zeng, N.; Yoon, J.; Mariotti, A.; Swenson, S. C.

2006-05-01

459

Hysteresis of Magnetite, Hematite and Pyrrhotite Crystals at High and Low Temperatures  

NASA Astrophysics Data System (ADS)

Alternating gradient force magnetometers and sensitive vibrating-sample magnetometers operating above, at, and below room temperature have enabled rapid reliable measurements of hysteresis and remanence curves. The hysteresis parameters Ms, Mrs, Hc, plus the remanence coercivity Hcr, are routinely determined, at room temperature at least, and reported in the form of a Day plot as an indication of domain state and inferred grain size. Yet our knowledge of the hysteresis and remanence properties of individual crystals or sized crystal aggregates of magnetite, titanomagnetite, hematite, pyrrhotite and other important magnetic minerals has scarcely advanced beyond what was known at the end of the 1980's. Applications have indeed outstripped fundamental studies. This presentation will focus on new hysteresis measurements for well-sized magnetites of a variety of origins; magnetite inclusions in plagioclase, pyroxene, amphiboles and biotite; hematite; and pyrrhotite. Measurements were made at 20oC intervals from 25oC to the Curie point for all magnetites and hematites and at 10oC intervals for pyrrhotite. For one set of sized magnetites (0.6, 3, 6, 9, 14 and 110 micrometers), hysteresis and back-field remanence curves were also measured below room temperature (every 10 K from 10 K to 70 K, every 5 K from 80 K to 140 K, and every 10 K from 150 K to 300 K). These data give a wealth of information about the individual mineral crystals and trends linking crystals of common origin but different sizes. From Ms(T) we obtain precise Curie points and transition temperatures. Mrs(T)/Ms(T) tracks sometimes subtle changes in domain structure with changing temperature. Hc(T) gives an indication of the mechanism(s) of anisotropy, important for understanding TRM acquisition in crystals above single-domain size. Mrs(T) and Hc(T) often show substantial irreversible changes in the first heating- cooling cycle, particularly but not exclusively for synthetic crystals, stabilizing in subsequent cycles. Finally, Mrs(T)/Ms(T) vs. Hcr(T)/Hc(T) data trace curves on a Day plot showing unmistakable differences in domain structure between monoclinic and cubic magnetite, as well as more subtle changes away from the Verwey transition.

Dunlop, D. J.

2008-12-01

460

First Measurement of Transferred Polarization in the Exclusive e-->p-->e'K+Lambda> Reaction  

Microsoft Academic Search

The first measurements of the transferred polarization for the exclusive e-->p-->e'K+Lambda--> reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567GeV beam was used to measure the hyperon polarization over Q2 from 0.3 to 1.5 (GeV\\/c)2, W from 1.6 to 2.15GeV, and over the full K+ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong

Daniel S. Carman; K. Joo; M. D. Mestayer; B. A. Raue; G. Adams; P. Ambrozewicz; E. Anciant; M. Anghinolfi; D. S. Armstrong; B. Asavapibhop; G. Audit; T. Auger; H. Avakian; H. Bagdasaryan; J. P. Ball; S. P. Barrow; M. Battaglieri; K. Beard; M. Bektasoglu; M. Bellis; C. Bennhold; N. Bianchi; A. S. Biselli; S. Boiarinov; B. E. Bonner; S. Bouchigny; R. Bradford; D. Branford; W. J. Briscoe; W. K. Brooks; V. D. Burkert; C. Butuceanu; J. R. Calarco; B. Carnahan; A. Cazes; C. Cetina; L. Ciciani; R. Clark; P. L. Cole; A. Coleman; D. Cords; P. Corvisiero; D. Crabb; H. Crannell; J. P. Cummings; E. Desanctis; P. V. Degtyarenko; H. Denizli; L. Dennis; R. Devita; K. V. Dharmawardane; K. S. Dhuga; C. Djalali; G. E. Dodge; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; O. P. Dzyubak; M. Eckhause; H. Egiyan; K. S. Egiyan; L. Elouadrhiri; A. Empl; P. Eugenio; R. Fatemi; G. Fedotov; R. J. Feuerbach; J. Ficenec; T. A. Forest; H. Funsten; S. J. Gaff; M. Gai; M. Garçon; G. Gavalian; S. Gilad; G. P. Gilfoyle; K. L. Giovanetti; P. Girard; E. Golovach; C. I. Gordon; K. Griffioen; S. Grimes; M. Guidal; M. Guillo; L. Guo; V. Gyurjyan; C. Hadjidakis; R. S. Hakobyan; J. Hardie; D. Heddle; P. Heimberg; F. W. Hersman; K. Hicks; R. S. Hicks; M. Holtrop; J. Hu; C. E. Hyde-Wright; B. Ishkhanov; M. M. Ito; D. Jenkins; J. H. Kelley; J. D. Kellie; M. Khandaker; K. Y. Kim; W. Kim; A. Klein; F. J. Klein; A. V. Klimenko; M. Klusman; M. Kossov; L. H. Kramer; Y. Kuang; S. E. Kuhn; J. Kuhn; J. Lachniet; J. M. Laget; D. Lawrence; J. Li; K. Livingston; A. Longhi; K. Lukashin; J. J. Manak; C. Marchand; T. Mart; S. McAleer; J. McCarthy; J. W. McNabb; B. A. Mecking; S. Mehrabyan; J. J. Melone; C. A. Meyer; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Mokeev; L. Morand; S. A. Morrow; M. U. Mozer; V. Muccifora; J. Mueller; L. Y. Murphy; G. S. Mutchler; J. Napolitano; R. Nasseripour; S. O. Nelson; S. Niccolai; G. Niculescu; I. Niculescu; B. B. Niczyporuk; R. A. Niyazov; M. Nozar; G. V. O'Rielly; A. K. Opper; M. Osipenko; K. Paschke; E. Pasyuk; G. Peterson; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; S. Pozdniakov; B. M. Preedom; J. W. Price; Y. Prok; D. Protopopescu; L. M. Qin; G. Riccardi; G. Ricco; M. Ripani; B. G. Ritchie; F. Ronchetti; P. Rossi; D. Rowntree; P. Rubin; F. Sabatié; K. Sabourov; C. Salgado; J. Santoro; V. Sapunenko; R. A. Schumacher; V. S. Serov; Y. G. Sharabian; J. Shaw; S. Simionatto; A. V. Skabelin; E. S. Smith; L. C. Smith; D. I. Sober; M. Spraker; A. Stavinsky; S. Stepanyan; P. Stoler; M. Taiuti; S. Taylor; D. J. Tedeschi; U. Thoma; R. Thompson; L. Todor; C. Tur; M. Ungaro; M. F. Vineyard; A. V. Vlassov; K. Wang; L. B. Weinstein; H. Weller; D. P. Weygand; C. S. Whisnant; E. Wolin; M. H. Wood; A. Yegneswaran; J. Yun; B. Zhang; J. Zhao; Z. Zhou

2003-01-01

461

Infection-stimulated infraosseus inflammation and bone destruction is increased in P-/E-selectin knockout mice  

PubMed Central

Infections of the dental pulp commonly result in infraosseus inflammation and bone destruction. However, the role of phagocytic leucocytes in the pathogenesis of pulpal infections has been uncertain. In this work we used P/E?/? selectin-deficient mice, which lack rolling adhesion of leucocytes to endothelium and mimic the human syndrome, leucocyte adhesion deficiency II (LAD-II), to test the hypothesis that phagocytic leucocytes protect against pulpal infection and subsequent periapical infraosseus bone resorption. P/E?/? mice and P/E+/+ wild-type controls were subjected to surgical pulp exposure, and both groups were infected with a mixture of pulpal pathogens including Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micros and Streptococcus intermedius. Animals were killed after 20 days, and the extent of infraosseus bone destruction was quantified by histomorphometry. In two separate experiments, P/E?/? mice had significantly greater bone resorption than P/E+/+ controls. The increased bone destruction correlated with a twofold decrease in polymorphonuclear (PMN) infiltration into periapical inflammatory tissues of P/E?/? mice. P/E?/? mice had higher tissue levels of the bone resorptive cytokine, interleukin (IL)-1?. Tissue levels of IL-2, IL-4, IL-10, tumour necrosis factor-? (TNF-?) and interferon-? (IFN-?) were all higher in P/E?/? mice, but the increases were not statistically significant. Only IL-12 was higher in P/E+/+ mice, possibly reflecting a greater number of infiltrating monocytes in wild-type mice. These findings demonstrate that phagocytic leucocytes are protective in this model, and suggest that elevated expression of inflammatory cytokines is responsible for the observed bone destruction. PMID:10447722

KAWASHIMA, N; NIEDERMAN, R; HYNES, R O; ULLMANN-CULLERE, M; STASHENKO, P

1999-01-01

462

Vortex loops and Majoranas  

SciTech Connect

We investigate the role that vortex loops play in characterizing eigenstates of interacting Majoranas. We give some general results and then focus on ladder Hamiltonian examples as a test of further ideas. Two methods yield exact results: (i) A mapping of certain spin Hamiltonians to quartic interactions of Majoranas shows that the spectra of these two examples coincide. (ii) In cases with reflection-symmetric Hamiltonians, we use reflection positivity for Majoranas to characterize vortices in the ground states. Two additional methods suggest wider applicability of these results: (iii) Numerical evidence suggests similar behavior for certain systems without reflection symmetry. (iv) A perturbative analysis also suggests similar behavior without the assumption of reflection symmetry.

Chesi, Stefano [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada) [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); CEMS, RIKEN, Wako, Saitama 351-0198 (Japan); Jaffe, Arthur [Harvard University, Cambridge, Massachusetts 02138 (United States) [Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Physics, University of Basel, Basel (Switzerland); Institute for Theoretical Physics, ETH Zürich, Zürich (Switzerland); Loss, Daniel [CEMS, RIKEN, Wako, Saitama 351-0198 (Japan) [CEMS, RIKEN, Wako, Saitama 351-0198 (Japan); Department of Physics, University of Basel, Basel (Switzerland); Pedrocchi, Fabio L. [Department of Physics, University of Basel, Basel (Switzerland)] [Department of Physics, University of Basel, Basel (Switzerland)

2013-11-15

463

Phase-Locked Loops  

NSDL National Science Digital Library

Phase-locked loops (PLL) are unique feedback control circuits that offer many useful features and benefits in electronic applications. PLLs are available either in integrated circuit (IC) form for general applications or built into larger system IC chips. Today, PLLs are found in virtually all types of electronic equipment from PCs to consumer products like TV sets and cell phones. This module provides an introduction to the PLL and its applications. It begins with an overview of the main components of a PLL and how these components work together. It then describes PLL specifications and a description of the most widely used applications including frequency synthesizers, clock multipliers, clock and data recovery circuits, FM demodulators, and filters.

464

Dynamic PID loop control  

SciTech Connect

The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.

Pei, L.; Klebaner, A.; Theilacker, J.; Soyars, W.; Martinez, A.; Bossert, R.; DeGraff, B.; Darve, C.; /Fermilab

2011-06-01

465

Sodium loop framework structural analysis  

SciTech Connect

This document provides the structural analysis of the Sodium Loop framework in a drop condition. The drop is similar to the US Department of Transportation non-bulk, performance-oriented packaging (Packaging Group I) drop test. The drop height evaluated for the Sodium Loop framework is 5.9 ft.

Nguyen, P.M.

1995-06-06

466

TRIAL MANUFACTURE OF BISMUTH LOOP  

Microsoft Academic Search

The outline of the structure of a bismuth loop is given. The loop was ; charged with bismuth by pressurizing the sumptank with nitrogen gas. In ; operation, the bismuth was pumped by means of a mechanical pump to III, II, and I ; vessels and a flowmeter. The temperature of bismuth metal was controlled at 550 ; deg C

S. Yajima; Y. Kamemoto; Y. Takahashi

1963-01-01

467

Thermodynamics in Loop Quantum Cosmology  

Microsoft Academic Search

Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective

Li-Fang Li; Jian-Yang Zhu

2009-01-01

468

Heating of braided coronal loops  

NASA Astrophysics Data System (ADS)

Aims: We investigate the relaxation of braided magnetic loops in order to find out how the type of braiding via footpoint motions affects resultant heating of the loop. Methods: Two magnetic loops, braided in different ways, are used as initial conditions in resistive MHD simulations and their subsequent evolution is studied. Results: The fields both undergo a resistive relaxation in which current sheets form and fragment and the system evolves towards a state of lower energy. In one case this relaxation is very efficient with current sheets filling the volume and homogeneous heating of the loop occurring. In the other case fewer current sheets develop, less magnetic energy is released in the process and a patchy heating of the loop results. The two cases, although very similar in their setup, can be distinguished by the mixing properties of the photospheric driver. The mixing can be measured by the topological entropy of the plasma flow, an observable quantity.

Wilmot-Smith, A. L.; Pontin, D. I.; Yeates, A. R.; Hornig, G.

2011-12-01

469

Loop Heat Pipe Startup Behaviors  

NASA Technical Reports Server (NTRS)

A loop heat pipe must start successfully before it can commence its service. The start-up transient represents one of the most complex phenomena in the loop heat pipe operation. This paper discusses various aspects of loop heat pipe start-up behaviors. Topics include the four start-up scenarios, the initial fluid distribution between the evaporator and reservoir that determines the start-up scenario, factors that affect the fluid distribution between the evaporator and reservoir, difficulties encountered during the low power start-up, and methods to enhance the start-up success. Also addressed are the thermodynamic constraint between the evaporator and reservoir in the loop heat pipe operation, the superheat requirement for nucleate boiling, pressure spike and pressure surge during the start-up transient, and repeated cycles of loop start-up andshutdown under certain conditions.

Ku, Jentung

2014-01-01

470

1 0 T H E K E T T E R I N G P E R S P E C T I V E For most, opening day of baseball  

E-print Network

1 0 T H E K E T T E R I N G P E R S P E C T I V E ON CA MPUS For most, opening day of baseball Physics at Kettering University, it's more like a test lab for his research into the physics of the "sweet spot," "sting" of bats and another way to make teach- ing Physics fun for students. Russell has used

Russell, Daniel A.

471

S E N I O R S P E C I A L I S T S P R O G R A M S C O P E O F W O R K  

E-print Network

S E N I O R S P E C I A L I S T S P R O G R A M 1 S C O P E O F W O R K Specialist's Name: Dawn Cork: Dawn Wright's Visit Fulbright Senior Specialist Program October 2004 Sat 9th , 11:15am: Dawn, Hogan Mezzanine o www.irlogi.ie/irlogievent.asp?EVENTID=10 - 9:45-10:15 - Dawn's Plenary address o "The

Wright, Dawn Jeannine

472

J A M E S B R O W N S U P E R V I S O R : D R . D M I T R Y P E L I N O V S K Y  

E-print Network

J A M E S B R O W N S U P E R V I S O R : D R . D M I T R Y P E L I N O V S K Y Multi-pulse do we measure error? Compare with exact solution. Compare Mn with unity Compare two successive iterations #12;One-Pulse Solution with no potential Exact Solution for #12;One-Pulse Solutions

Pelinovsky, Dmitry

473

Assessment of the hydrological behaviour of watersheds of contrasting land use using suspended sediment-discharge hysteresis patterns  

NASA Astrophysics Data System (ADS)

Four experimental watersheds in Navarre (Spain), maintained by the local government, have been monitored and studied since 1996 (La Tejería and Latxaga) and 2001 (Oskotz "principal", Op, and Oskotz "woodland", Ow). La Tejería and Latxaga watersheds, located in the central western part of Navarre, are roughly similar to each other regarding size (approximately 200 ha), geology (marls and sandstones), soils (alkaline, fine texture topsoil), climate (humid sub Mediterranean) and land use (80-90% cultivated with winter grain crops). On the other hand, Op (ca.1,700 ha) is covered with forest and pasture (cattle-breeding); while Ow (ca. 500 ha), a sub-watershed of the Op, is almost completely covered with forest. The predominant climate in Op/Ow is sub-Atlantic. As a result, a detailed description and a general characterization of the hydrological and erosion behaviour of these watersheds were published recently by the same authors of this current research. However, this information, although extensive and valuable, is still insufficient for finding out the internal and complex hydrological functioning of these watersheds reflected in the frequent occurrence of the hysteresis phenomenon. "Hysteresis" is when the amount of sediment concentration associated with a certain flow is different depending on the direction in which the analysis is performed -towards the increase or towards the diminution of the flow. This phenomenon to some extent reflects the way in which the runoff generation processes are conjugated with those of the production and transport of sediments, hence the usefulness of hysteresis as a diagnostic hydrological parameter. However, the complexity of the phenomena and factors which determine hysteresis make its interpretation uncertain or, at the very least, problematic. 5 types of hysteresis have been recognized but, however, only three types are usually reported: "clockwise", "anticlockwise" and "eight-shape". This article aims to investigate the hydrological-erosion behaviour of 4 watersheds with contrasting land uses by means of the analysis and interpretation of the sediment-flow relationship throughout a long period of time. The first results of this work are presented here. The sediment-flow relationship of 375 events occurring between 1996 and 2009 in the La Tejería, Latxaga, Ow and Op watersheds was analyzed seeking to identify events presenting hysteresis. To make the comparison between events easier a normalized hysteresis index was calculated -although it was only applicable for clockwise and anticlockwise hysteresis- based on the determination of the area comprised between the top and bottom limbs of the sediment-flow graph. Only 25-60% of the events taking place in the grain-cultivated watersheds exhibited a clear hysteresis. Conversely, in Op/Ow this figure rose to 95%. In the watersheds cultivated with grain, the factors controlling erosion -protection due to cultivation, tillage, etc.- can change drastically throughout the year and even inside one same watershed, so that it is not surprising that the sediment-flow relationship did not show a clear hysteresis, unlike what happened in the watersheds under woodland/pasture. In general, 3 types of hysteresis were observed: clockwise, anticlockwise and eight-shape, although the first of these was predominant. It was, thus, in Op/Ow that 90% of the events which displayed hysteresis did so with the clockwise type, whereas in La Tejería this rate was only 50%. Also, the hysteresis in Op/Ow and Laxtaga was more clearly defined (a higher index) than that in La Tejería. This predominance of curves with clockwise hysteresis