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1

Anomalous Ferroelectric Hysteresis Loops.  

National Technical Information Service (NTIS)

Materials that exhibit anomalous ferroelectric hysteresis loops appear throughout the literature. These loops have irregular shapes that diverge from the normal hysteresis loop which is characteristic of most ferroelectrics. The observation of a unique hy...

F. J. Murdoch

1971-01-01

2

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

3

Analysis of wasp-waist hysteresis loops  

NASA Astrophysics Data System (ADS)

Wasp-waist and pot-belly hysteresis loops have been observed in many materials. When only the major loop is reported, the results are insufficient to establish which processes are involved. We present two models for wasp-waist materials that produce virtually indistinguishable major loops, but show that first-order reversal curves can be used to separate the effects. In the simplest model, we take a soft magnetic material and a hard material and exchange couple them. When the exchange is positive, the loop is conventional. However, for negative (antiferromagnetic) exchange, the wasp-waist loop is obtained. Negative coupling of two materials with different switching field distributions leads to pot-bellied loops.

Bennett, Lawrence H.; Della Torre, Edward

2005-05-01

4

PC Based Pulsed Field Hysteresis Loop Tracer  

NASA Astrophysics Data System (ADS)

The present paper describes the design and setting up of a PC based hysteresis loop tracer that enables quick characterization of magnetic materials at room temperature. A high magnetic field is generated in a solenoid by passing a pulse current of sinusoidal shape at an interval slow enough to produce minimum heating in the solenoid. A pickup coil system is kept in the solenoid to detect field and magnetization signal of a sample placed in the pickup coil. These transitory analog signals are converted into digital signals by a micro-controller integrated circuit. These digital signals are sent to a computer through a serial port. A software has been developed to interface the system to the PC and processing the data to calculate hysteresis parameters like saturation magnetization Ms, coercivity Hc and remanence Mr followed by plotting of the hysteresis loop. The data and graphs can be printed or stored as files. The sample holder is designed for samples in powder or pellet form. The data acquired for some standard magnetic samples are presented.

Likhite, S. D.; Likhite, Prachi; Radha, S.

2011-07-01

5

Lumped-circuit models for nonlinear inductors exhibiting hysteresis loops  

Microsoft Academic Search

A new mathematical model of dynamic hysteresis loops is presented. The model is completely specified by two strictly monotonically increasing functions: a restoring function f(.) and a dissipation function g(.). Simple procedures are given for constructing these two functions so that the resulting model will simulate a given hysteresis loop exactly. The model is shown to exhibit many important hysteretic

L. Chua; K. Stromsmoe

1970-01-01

6

Circuit measures hysteresis loop areas at 30 Hz  

NASA Technical Reports Server (NTRS)

Analog circuit measures hysteresis loop areas as a function of time during fatigue testing of specimens subjected to sinusoidal tension-compression stresses at a frequency of Hz. When the sinusoidal stress signal is multiplied by the strain signal, the dc signal is proportional to hysteresis loop area.

Hoffman, C.; Spilo, D.

1967-01-01

7

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

8

Cumulative growth of minor hysteresis loops in the Kolmogorov model  

SciTech Connect

The phenomenon of nonrepeatability of successive remagnetization cycles in Co/M (M = Pt, Pd, Au) multilayer film structures is explained in the framework of the Kolmogorov crystallization model. It is shown that this model of phase transitions can be adapted so as to adequately describe the process of magnetic relaxation in the indicated systems with 'memory.' For this purpose, it is necessary to introduce some additional elements into the model, in particular, (i) to take into account the fact that every cycle starts from a state 'inherited' from the preceding cycle and (ii) to assume that the rate of growth of a new magnetic phase depends on the cycle number. This modified model provides a quite satisfactory qualitative and quantitative description of all features of successive magnetic relaxation cycles in the system under consideration, including the surprising phenomenon of cumulative growth of minor hysteresis loops.

Meilikhov, E. Z., E-mail: meilikhov@imp.kiae.ru; Farzetdinova, R. M. [National Research Centre Kurchatov Institute (Russian Federation)] [National Research Centre Kurchatov Institute (Russian Federation)

2013-01-15

9

EXISTENCE OF FINITELY MANY SOLUTION BRANCHES AND NESTED HYSTERESIS LOOPS IN FERROELECTRIC MATERIALS  

E-print Network

. This results in nucleations and domain walls, and a relation between polarization and applied field, iEXISTENCE OF FINITELY MANY SOLUTION BRANCHES AND NESTED HYSTERESIS LOOPS IN FERROELECTRIC MATERIALS and Nested Hysteresis Loops in Ferroelectric Materials Jinhae Park Department of Mathematics Purdue

10

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

11

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

12

A modified Jiles method for hysteresis computation including minor loops  

NASA Astrophysics Data System (ADS)

This work presents a new methodology for determination of hysteresis curves based on the Jiles-Atherton method. The magnetic induction is adopted as an independent variable which is available in the vector potential magnetic field formulation. The presented method can be directly incorporated in a finite element software.

Koltermann, P. I.; Righi, L. A.; Bastos, J. P. A.; Carlson, R.; Sadowski, N.; Batistela, N. J.

2000-01-01

13

Non centered minor hysteresis loops evaluation based on exponential parameters transforms of the modified inverse Jiles-Atherton model  

NASA Astrophysics Data System (ADS)

In this present work, a non centered minor hysteresis loops evaluation is performed using the exponential transforms (ET) of the modified inverse Jiles-Atherton model parameters. This model improves the non centered minor hysteresis loops representation. The parameters of the non centered minor hysteresis loops are obtained from exponential expressions related to the major ones. The parameters of minor loops are obtained by identification using the stochastic optimization method “simulated annealing”. The four parameters of JA model (a,?, k and c) obtained by this transformation are applied only in both ascending and descending branches of the non centered minor hysteresis loops while the major ones are applied to the rest of the cycle. This proposal greatly improves both branches and consequently the minor loops. To validate this model, calculated non-centered minor hysteresis loops are compared with measured ones and good agreements are obtained.

Hamimid, M.; Mimoune, S. M.; Feliachi, M.; Atallah, K.

2014-10-01

14

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

15

Unzipping DNA by a periodic force: hysteresis loop area and its scaling  

E-print Network

We study, by using Monte Carlo simulations, the hysteresis in unzipping of a double stranded DNA whose ends are subjected to a time dependent periodic force with frequency ($\\omega$) and amplitude ($G$). For the static force, i.e., $\\omega \\to 0$, the DNA is in equilibrium with no hysteresis. On increasing $\\omega$, the area of the hysteresis loop initially increases and becomes maximum at frequency $\\omega^{*}(G)$, which depends on the force amplitude $G$. If the frequency is further increased, we find that for lower amplitudes the loop area decreases monotonically to zero, but for higher amplitudes it has an oscillatory component. The height of subsequent peaks decrease and finally the loop area becomes zero at very high frequencies. The number of peaks depend on the length of the DNA. We give a simple analysis to estimate the frequencies at which maxima and minima occurs in the loop area. We find that the area of the hysteresis loop scales as $1/\\omega$ in high frequency regime whereas, it scales as $G^{\\a...

Kapri, Rajeev

2014-01-01

16

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

17

Segmented shape memory alloy actuators using hysteresis loop control  

NASA Astrophysics Data System (ADS)

A new approach to the design and control of shape memory alloy (SMA) actuators is presented. SMA wires are divided into many segments and their thermal states are controlled individually as a group of finite state machines. Instead of driving a current to the entire SMA wire and controlling the wire length based on the analog strain-temperature characteristics, the new method controls the binary state (hot or cold) of individual segments and thereby the total displacement is proportional to the length of the heated segments, i.e. austenite phase. Although the thermomechanical properties of SMA are highly nonlinear and uncertain with a prominent hysteresis, segmented binary control is robust and stable, providing characteristics similar to a stepping motor. However, the heating and cooling of each segment to its bi-stable states entail longer time and larger energy for transition. In this paper, an efficient method for improving the speed of response and power consumption is developed by exploiting the inherent hysteresis of SMA. Instead of keeping the extreme temperatures continuously, the temperatures return to intermediate 'hold' temperatures closer to room temperature but sufficient to keep constant phase. Coordination of the multitude of segments having independent thermal states allows for faster response with little latency time even for thick SMA wires. Based on stress dependent thermomechanical characteristics, the hold temperature satisfying a given stress margin is obtained. The new control method is implemented using the Peltier effect thermoelectric devices for selective segment-by-segment heating and cooling. Experiments demonstrate the effectiveness of the proposed method.

Selden, Brian; Cho, Kyujin; Asada, H. Harry

2006-04-01

18

Estimate interface frictional coefficient of ceramic matrix composites from hysteresis loops  

Microsoft Academic Search

An approach to estimate fiber\\/matrix interface frictional coefficient of ceramic matrix composites under fatigue loading is developed by means of hysteresis loops. The Coulomb friction law is adopted to describe the interface shear stress in the debonded region. The matrix crack space and interface debonded length are obtained by matrix statistical cracking model and fracture mechanics interface debonding criterion. The

Longbiao Li; Yingdong Song

2011-01-01

19

Study on D-E Hysteresis Loop of TGS Based on the Avrami-Type Model  

NASA Astrophysics Data System (ADS)

We measured the D-E hysteresis loop of TGS (triglycine sulphate), and transformed it to the q-E hysteresis loop by a method proposed in this paper, where q is the volume fraction of reversed domains. The experimental result was compared with a theory based on the Avrami model by the present authors [H. Orihara, S. Hashimoto and Y. Ishibashi: J. Phys. Soc. Jpn. 63 (1994) 1031], in which the volume fraction is expressed as q(E)=1-exp(-f-d?(E)), where f and d are, respectively, the frequency of the applied field and the growth dimension of domains, and ? is a function of E. We obtained a good agreement between them and confirmed the validity of our theory. The frequency dependences of the coercive field and the area inside the loop were measured and power laws were obtained with respect to them, which are discussed on the basis of the theory.

Hashimoto, Shigeharu; Orihara, Hiroshi; Ishibashi, Yoshihiro

1994-04-01

20

Simulations of magnetic hysteresis loops at high temperatures  

NASA Astrophysics Data System (ADS)

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.; van Ek, J.; Whitehead, J. P.; Fal, T. J.; Mercer, J. I.

2014-09-01

21

Estimate Interface Shear Stress of Woven Ceramic Matrix Composites from Hysteresis Loops  

NASA Astrophysics Data System (ADS)

An approach to estimate the fiber/matrix interface shear stress of woven ceramic matrix composites during fatigue loading has been developed in this paper. Based on the analysis of the microstructure, the woven ceramic matrix composites were divided into four elements of 0o warp yarns, 90o weft yarns, matrix outside of the yarns and the open porosity. When matrix cracking and fiber/matrix interface debonding occur upon first loading to the peak stress, it is assumed that fiber slipping relative to matrix in the interface debonded region of the 0o warp yarns is the mainly reason for the occurrence of the hysteresis loops of woven ceramic matrix composiets during unloading and subsequent reloading. The unloading interface reverse slip length and reloading interface new slip length are determined by the interface slip mechanisms. The hysteresis loops of three different cases have been derived. The hysteresis loss energy for the strain energy lost per volume during corresponding cycle is formulated in terms of the fiber/matrix interface shear stress. By comparing the experimental hysteresis loss energy with the computational values, the fiber/matrix interface shear stress of woven ceramic matrix composites corresponding to different cycles can then be derived. The theoretical results have been compared with experimental data of two different woven ceramic composites.

Li, Longbiao; Song, Yingdong

2013-12-01

22

Magnetic Study of Martensitic Transformation in Austenitic Stainless Steel by Low Field Hysteresis Loops Analysis  

SciTech Connect

Magnetic method has been used to evaluate the volume percentage of {alpha}' martensitic phase in austenitic stainless steels by measuring saturation magnetization, and it is said to be a candidate NDE method. However, nondestructive detection of saturation magnetization without high magnetic field is difficult. In the current work, we present a NDE method for evaluating the magnetic properties of strain induced {alpha}' martensitic phase. Low field hysteresis loops of an austenitic stainless steels type SUS 304 after cold rolling were measured by using a yoke sensor. The results show that the initial permeability {mu}i and the relative coercive field Hcl calculated by low field hysteresis loop analysis keep monotonic relation with saturation magnetization and coercive force measured by VSM, respectively. By this method, it is possible to characterize the volume content and particle properties of {alpha}' martensitic phase in stainless steels.

Zhang Lefu; Takahashi, Seiki; Kamada, Yasuhiro; Kikuchi, Hiroaki; Mumtaz, Khalid; Ara, Katsuyuki; Sato, Masaya [NDE Center, Faculty of Engineering, Iwate University, Morioka, 020-8551 (Japan)

2005-04-09

23

Hysteresis loop and scanning curves of argon adsorption in closed-end wedge pores.  

PubMed

The hysteresis loop and scanning curves for argon adsorbed in a wedge pore with one end closed are studied with grand canonical Monte Carlo simulation. We have found multiple hysteresis loops for pores with either the narrow end or the wider end closed. In pores with the narrow end closed, adsorption and desorption exhibits a two-stage sequence of rapid change, followed by a gradual change in adsorbate density. The pore can be divided into zones of commensurate packing and junctions of incommensurate packing. A striking feature is that the sequence of these two stages is opposite for the adsorption and desorption processes. This can be explained by cohesion in the adsorbate, in which a steep condensation process is associated with the zones and a steep evaporation process is associated with the junctions between them. For pores with the wider end closed, the processes of adsorption and desorption from various zones are correlated with each other. In pores with the narrow end closed, the scanning curves trace reversibly along the segment of the isotherm, where the isotherm shows gradual change, and when the scanning curve reaches a point between the gradual change segment and the sharp change segment, the scanning curve crosses from one boundary of the hysteresis loop to the corresponding point on the other boundary. This indicates that the condensation and evaporation states are not affected by scanning but that, in scanning across the hysteresis loop, the adsorbate passes through a sequence of metastable states as the distribution of density is rearranged, without any significant change in the overall density. In contrast, for pores with the wider end closed, both the descending curve from a partially filled pore and the ascending curve are identical to the desorption branch of the corresponding pore with its narrow end closed. PMID:25314672

Klomkliang, Nikom; Do, D D; Nicholson, D

2014-11-01

24

Surface layer on KNbO 3 and the hysteresis loop anomaly  

Microsoft Academic Search

An anomaly in the hysteresis loop of the polarisation of KNbO3 is observed at low frequencies. This gives a value for the remanent polarisation which is an order of magnitude larger than that in the frequency regime of traditional measurements. We correlate this observation with the specific properties of the surfaces of ABO3-type perovskites. Surface analytical methods are used to

K. Szot; W. Speier; S. Cramm; J. Herion; Ch. Freiburg; R. Waser; M. Pawe?czyk; W. Eberhard

1996-01-01

25

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

26

Defect-induced asymmetry of local hysteresis loops on BiFeO 3 surfaces  

Microsoft Academic Search

Local piezoresponse hysteresis loops were systematically studied on the surface of ferroelectric thin films of BiFeO3 grown on SrRuO3 and La0.7Sr0.3MnO3 electrodes and compared between ultrahigh vacuum and ambient environment. The loops on all the samples exhibited characteristic\\u000a asymmetry manifested in the difference of the piezoresponse slope following local domain nucleation. Spatially resolved mapping\\u000a has revealed that the asymmetry is

Peter Maksymovych; Nina Balke; Stephen Jesse; Mark Huijben; Ramamoorthy Ramesh; Arthur P. Baddorf; Sergei V. Kalinin

2009-01-01

27

Field dependent resonance frequency of hysteresis loops in a few monolayer thick Co\\/Cu(001) films  

Microsoft Academic Search

Dynamic responses of magnetic hysteresis loops in a few monolayer (ML) thick Co\\/Cu(001) films were studied using surface magneto-optic Kerr effect (SMOKE). For a fixed external field strength H0, the hysteresis loop area increases as a function of frequency with a power law and reaches a maximum at a resonance frequency ?0. This ?0 depends on the external periodic field

Q. Jiang; H.-N. Yang; G.-C. Wang

1996-01-01

28

Terfenol-D elastomagnetic properties under varied operating conditions using hysteresis loop analysis  

NASA Astrophysics Data System (ADS)

This paper presents an experimental study of the effects of varied magnetic bias, AC magnetic field amplitude and frequency on the characteristics of hysteresis loops produced in a magnetostrictive transducer. The study uses a magnetostrictive transducer designed at Iowa State University that utilizes an 11.5 cm (4.54 in) long by 1.27 cm (0.5 in) diameter cylindrical Terfenol-D rod. This transducer allows controlled variation of the following operating conditions: mechanical prestress, magnitude and frequency of AC magnetic field, and magnetic bias. By performing extensive experimental tests, material property trends can be developed for use in the optimization of transducer design parameters for different applications. For the results presented, the magnetic bias, the AC magnetic field amplitude, and the frequency of excitation were independently varied while temperature, mass load and prestress were kept constant. The minor hysteresis loops of the strain versus applied magnetic field, flux density versus applied magnetic field, and magnetization versus applied magnetic field are presented and compared. Material property trends identified from the minor loops are presented for the axial strain coefficient, permeability, susceptibility, and energy losses.

Faidley, LeAnn E.; Lund, Brian J.; Flatau, Alison B.; Calkins, Frederick T.

1998-07-01

29

Comparison of hysteresis loop area scaling behavior of Co/Pt multilayers: Discrete and continuous field sweeping  

NASA Astrophysics Data System (ADS)

We have investigated the hysteresis loop shape changes with discrete and continuous magnetic field sweeping for Co/Pt multilayers with a perpendicular magnetic anisotropy. The hysteresis loop shape was observed by measuring a polar magneto-optical Kerr effect. The loop area has been found to increase rapidly with an increase of the field step size as well as the sweeping frequency until the area reaches a maximum. The increase of the loop area has been analyzed based on the Steinmetz law, where a loop area scaling exponent determined from discrete field sweeping is compared to a scaling exponent from continuous field sweeping. The dynamic coercivity behavior with respect to discrete and continuous field sweeping is analyzed together with the loop area scaling behavior, suggesting that details of magnetic configuration disorders do not modify the loop area scaling exponent.

Handoko, Djati; Lee, Sang-Hyuk; Min Lee, Kyung; Jeong, Jong-Ryul; Kim, Dong-Hyun

2014-02-01

30

Self-magnetic compensation and shifted hysteresis loops in ferromagnetic samarium systems  

NASA Astrophysics Data System (ADS)

For Sm3+ ions in a vast majority of metallic systems, the following interesting scenario has been conjured up for long, namely, a magnetic lattice of tiny self- (spin-orbital) compensated 4f -moments exchange coupled (and phase reversed) to the polarization in the conduction band. We report here the identification of a self-compensation behavior in a variety of ferromagnetic Sm intermetallics via the fingerprint of a shift in the magnetic hysteresis (M-H) loop from the origin. Such an attribute, designated as exchange bias in the context of ferromagnetic/antiferromagnetic multilayers, accords these compounds a potential for niche applications in spintronics. We also present results on magnetic compensation behavior on small Gd doping (2.5at.%) in one of the Sm ferromagnets (viz., SmCu4Pd ). The doped system responds like a pseudoferrimagnet and it displays a characteristic left-shifted linear M-H plot for an antiferromagnet.

Kulkarni, P. D.; Dhar, S. K.; Provino, A.; Manfrinetti, P.; Grover, A. K.

2010-10-01

31

Article surveillance magnetic marker having an hysteresis loop with large Barkhausen discontinuities  

DOEpatents

A marker for an electronic article surveillance system is disclosed comprising a body of magnetic material with retained stress and having a magnetic hysteresis loop with a large Barkhausen discontinuity such that, upon exposure of the marker to an external magnetic field whose field strength in the direction opposing the instantaneous magnetic polarization of the marker exceeds a predetermined threshold value, there results a regenerative reversal of the magnetic polarization of the marker. An electronic article surveillance system and a method utilizing the marker are also disclosed. Exciting the marker with a low frequency and low field strength, so long as the field strength exceeds the low threshold level for the marker, causes a regenerative reversal of magnetic polarity generating a harmonically rich pulse that is readily detected and easily distinguished.

Humphrey, Floyd B. (Bradfordwoods, PA)

1987-01-01

32

Thin films of spin-crossover coordination polymers with large thermal hysteresis loops prepared by nanoparticle spin coating.  

PubMed

This communication describes the synthesis of spin-crossover nanoparticles, which can disperse in various organic solvents without an excess amount of surfactants. The nanoparticles form homogeneous thin films on substrates by spin coating. The films show abrupt spin transitions with large thermal hysteresis loops. PMID:25045761

Tanaka, Daisuke; Aketa, Naoki; Tanaka, Hirofumi; Tamaki, Takashi; Inose, Tomoko; Akai, Tomoki; Toyama, Hirotaka; Sakata, Osami; Tajiri, Hiroo; Ogawa, Takuji

2014-09-11

33

The magnetization process: Hysteresis  

NASA Technical Reports Server (NTRS)

The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

Balsamel, Richard

1990-01-01

34

Magnetization Process: Hysteresis.  

National Technical Information Service (NTIS)

The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hyste...

R. Balsamel

1990-01-01

35

Hysteresis loop and pattern from the dual-wavelength competition in an Nd:YVO4 laser with an intracavity periodically poled lithium niobate Bragg modulator  

NASA Astrophysics Data System (ADS)

This study demonstrates hysteresis loop and pattern formation in a Nd:YVO4 laser at 1064nm (4F3/2 ?4I1 1/2) and 1342nm (4F3/2?4I13/2) with an intracavity electro-optic periodically poled lithium niobate (EO PPLN) Bragg modulator by using a T-type cavity configuration. Based on these dual wavelengths sharing population inversion in the same upper energy level to lase, the transmission, Tp, of EO PPLN was chosen as the controlling parameter to explore the dynamics of dualwavelength competition. A hysteresis loop occurred when the extracting efficiencies of dual wavelength were near equivalent. When the pump power was 9.0 W, the hysteresis loop was observed in the region of the transmission of PPLN between Tp=64.88% to Tp=84.47%. The slope efficiencies were 25.96 and 3.92% and the thresholds were 2.5 and 3.5 W for the wavelengths of 1064 and 1342 nm, respectively. The width of the hysteresis loop increased when the pump power increased. Moreover, the hysteresis loop accompanied with the variation of the pattern formation. A high-order transvers mode was easily observed at 1342 nm light, but a simple spot existed for 1064 nm light. Apparently, the role of gain competition is worthy to deeply explore.

Hong, Kun-Guei; Lin, Shou-Tai; Wei, Ming-Dar

2014-10-01

36

Estimate Interface Shear Stress of Unidirectional C/SiC Ceramic Matrix Composites from Hysteresis Loops  

NASA Astrophysics Data System (ADS)

The tensile-tensile fatigue behavior of unidirectional C/SiC ceramic matrix composites at room and elevated temperature has been investigated. An approach to estimate the interface shear stress of ceramic matrix composites under fatigue loading has been developed. Based on the damage mechanisms of fiber sliding relative to matrix in the interface debonded region upon unloading and subsequent reloading, the unloading interface reverse slip length and reloading interface new slip length are determined by the fracture mechanics approach. The hysteresis loss energy for the strain energy lost per volume during corresponding cycle is formulatd in terms of interface shear stress. By comparing the experimental hysteresis loss energy with the computational values, the interface shear stress of unidirectional C/SiC ceramic composites corresponding to different cycles at room and elevated temperatures has been predicted.

Longbiao, Li; Yingdong, Song; Youchao, Sun

2013-08-01

37

Evolution of Recrystallization by Changes in Magnetic Hysteresis Loop in a Non-Oriented Electric Steel Cold Rolled  

NASA Astrophysics Data System (ADS)

Non-oriented steels, with low carbon, are widely used in the fabrication of electrical motor nucleus. The performance of these motors is affected by the level of recrystallization. These steels can come from the steel plant in two different conditions: totally processed or semi-processed. The semi-processed steels have a partially deformed structure and are submitted to the final annealing process after reaching the end shape. An adequate annealing heat treatment is important to get an appropriate magnetic property. In the present study, samples of an electric steel, with the composition (0.05 wt% C, 1.28wt% Si, 0.29wt% Mn), cold rolled 50% in thickness, were withdrawn during the industrial heat treatment at temperatures of 575, 580, 600, 620 and 730 °C with the objective of evaluating the evolution of recrystalization with temperature. Magnetic properties were measured at room temperature in a vibrating sample magnetometer. Although the changes in magnetic hysteresis loop with temperature are difficult to observe, they have been identified by using pattern classification techniques, such as principal-component analysis and Karhunen-Loève expansion. These tools have been applied to vectors which are built from each hysteresis loop, properly renormalized, whose components correspond to amplitude of the loop at given equally spaced values of the renormalized field. The samples have been classified in four sets, namely, set A corresponding to temperatures 575/580, set B corresponding to temperatures 600/620, set C corresponding to the samples without annealing heat treatment, and set D corresponding to recrystallized samples. The results for the classification of the different microstructures have been obtained by using both techniques, and in particular a 100% success rate has been reached by using Karhunen-Loève expansion.

da Silva, F. E.; Freitas, F. N. C.; Abreu, H. F. G.; Gonçalves, L. L.; Moura, E. P.; Silva, M. R.

2011-06-01

38

Dissipative and hysteresis loops as images of irreversible processes in nonlinear acoustic fields  

NASA Astrophysics Data System (ADS)

Irreversible processes taking place during nonlinear acoustic wave propagation are considered using a representation by loops in a thermodynamic parameter space. For viscous and heat conducting media, the loops are constructed for quasi-harmonic and sawtooth waves and the descriptive equations are formulated. The linear and nonlinear absorptions are compared. For relaxing media, the processes are frequency-dependent. The loops broadens, narrows, and bends. The linear and nonlinear relaxation losses of wave energy are shown. Residual stresses and irreversible strains appear for hysteretic media, and here, a generalization of Rayleigh loops is pictured which takes into account the nonlinearly frequency-dependent hereditary properties. These describe the dynamic behavior, for which new equations are derived.

Hedberg, C. M.; Rudenko, O. V.

2011-09-01

39

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

40

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

41

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

PubMed

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. PMID:25273736

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

2014-09-01

42

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

43

Mechanism of the hysteretic behavior of the magnetoresistance of granular HTSCs: The universal nature of the width of the magnetoresistance hysteresis loop  

SciTech Connect

The hysteretic behavior of the magnetoresistance R(H) of granular high-temperature superconductors (HTSCs) of the Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O, and La-Sr-Cu-O classical systems is investigated for transport current densities lower and higher than the critical density (at H = 0). All systems exhibit universal behavior of the width of the magnetoresistance hysteresis loop: independence of transport current under identical external conditions. This means that flux trapping in HTSC grains is the main mechanism controlling the hysteretic behavior of the magnetoresistance of granular HTSCs, while pinning of Josephson vortices in the intragranular medium makes no appreciable contribution to the formation of magnetoresistance hysteresis (when transport current flows through the sample). Experimental data on relaxation of residual resistance after the action of a magnetic field also confirm this conclusion.

Balaev, D. A., E-mail: smp@iph.krasn.ru; Dubrovskii, A. A.; Shaikhutdinov, K. A.; Popkov, S. I.; Gokhfeld, D. M.; Gokhfeld, Yu. S.; Petrov, M. I. [Russian Academy of Sciences, Kirenskii Institute of Physics, Siberian Branch (Russian Federation)

2009-02-15

44

Study of a Radial-Exiting Hysteresis Gyro Motor.  

National Technical Information Service (NTIS)

Conventional hysteresis motors have small ratios of the output power to the motor volume as compared with conventional induction motors, because the hysteresis materials have small hysteresis loops. A new rotor structure is proposed in which anisotropic m...

H. Yamada

1973-01-01

45

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys  

NASA Technical Reports Server (NTRS)

Limited experimental data exists for the specific core loss and dynamic B-H loops for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

46

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys  

NASA Technical Reports Server (NTRS)

Limited experimental data exists for the specific core loss and dynamic B-H loop for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

47

Double polarization hysteresis loop induced by the domain pinning by defect dipoles in HoMnO3 epitaxial thin films  

NASA Astrophysics Data System (ADS)

We report on antiferroelectriclike double polarization hysteresis loops in multiferroic HoMnO3 thin films below the ferroelectric Curie temperature. This intriguing phenomenon is attributed to the domain pinning by defect dipoles which were introduced unintentionally during film growth process. Electron paramagnetic resonance suggests the existence of Fe1+ defects in thin films and first-principles calculations reveal that the defect dipoles would be composed of oxygen vacancy and Fe1+ defect. We discuss migration of charged point defects during film growth process and formation of defect dipoles along ferroelectric polarization direction, based on the site preference of point defects. Due to a high-temperature low-symmetry structure of HoMnO3 , aging is not required to form the defect dipoles in contrast to other ferroelectrics (e.g., BaTiO3 ).

Lee, D.; Kim, H. S.; Jang, S. Y.; Joh, K. W.; Noh, T. W.; Yu, J.; Lee, C. E.; Yoon, J.-G.

2010-01-01

48

Ab initio study of pressure stabilized NiTi allotropes: Pressure-induced transformations and hysteresis loops  

NASA Astrophysics Data System (ADS)

Changes in stoichiometric NiTi allotropes induced by hydrostatic pressure have been studied employing density functional theory. By modeling the pressure-induced transitions in a way that imitates quasistatic pressure changes, we show that the experimentally observed B19' phase is (in its bulk form) unstable with respect to another monoclinic phase, B19''. The lower symmetry of the B19'' phase leads to unique atomic trajectories of Ti and Ni atoms (that do not share a single crystallographic plane) during the pressure-induced phase transition. This uniqueness of atomic trajectories is considered a necessary condition for the shape memory ability. The forward and reverse pressure-induced transition B19' ? B19'' exhibits a hysteresis that is shown to originate from hitherto unexpected complexity of the Born-Oppenheimer energy surface.

Holec, David; Friák, Martin; Dlouhý, Antonín; Neugebauer, Jörg

2011-12-01

49

M P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E J Mathematical Physics Electronic Journal  

E-print Network

space, the support of the measure consisting of solutions of the Navier-Stokes equations, see [VF P E JM P E JM P E JM P E JM P E JM P E JM P E J Mathematical Physics Electronic Journal ISSN 1086 to homogeneous measures on such vector fields is examined. The space average, obtained by integration over balls

Chapman, Robin

50

M P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E JM P E J Mathematical Physics Electronic Journal  

E-print Network

are the generalization of KAM tori in the non-differentiable case. These sets support invariant measures, the Mather P E JM P E JM P E JM P E JM P E JM P E JM P E J Mathematical Physics Electronic Journal ISSN 1086 measures, which are action minimizing measures. We generalize viscosity solution methods to study discrete

Chapman, Robin

51

Mathematical models of hysteresis  

SciTech Connect

The ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema (not the entire input variations) leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. The origin of such tools can be traced back to the landmark paper of Preisach. Their research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. During the past four years, the study has been by and large centered around the following topics: (1) further development of Scalar and vector Preisach-type models of hysteresis; (2) experimental testing of Preisach-type models of hysteresis; (3) development of new models for viscosity (aftereffect) in hysteretic systems; (4) development of mathematical models for superconducting hysteresis in the case of gradual resistive transitions; (5) software implementation of Preisach-type models of hysteresis; and (6) development of new ideas which have emerged in the course of the research work. The author briefly describes the main scientific results obtained in the areas outlined above.

NONE

1998-08-01

52

Hysteresis Simulation  

NSDL National Science Digital Library

You can choose from three values for disorder of the system and select a goal for the external magnetic field by clicking in a "control bar" area. Output graphs show qualitative information, but no numbers. A brief explanation of the physics of hysteresis is provided and the java source code can be downloaded.

Houle, Paul

53

[Mathematical models of hysteresis  

SciTech Connect

The research described in this proposal is currently being supported by the US Department of Energy under the contract Mathematical Models of Hysteresis''. Thus, before discussing the proposed research in detail, it is worthwhile to describe and summarize the main results achieved in the course of our work under the above contract. Our ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories''. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. Our research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. Our study has by and large been centered around the following topics: various generalizations and extensions of the classical Preisach model, finding of necessary and sufficient conditions for the representation of actual hysteretic nonlinearities by various Preisach type models, solution of identification problems for these models, numerical implementation and experimental testing of Preisach type models. Although the study of Preisach type models has constituted the main direction of the research, some effort has also been made to establish some interesting connections between these models and such topics as: the critical state model for superconducting hysteresis, the classical Stoner-Wohlfarth model of vector magnetic hysteresis, thermal activation type models for viscosity, magnetostrictive hysteresis and neural networks.

Mayergoyz, I.D.

1991-01-01

54

Preisach modeling of piezoceramic and shape memory alloy hysteresis  

Microsoft Academic Search

Smart materials such as piezoceramics and shape memory alloys (SMAs) exhibit significant hysteresis and in order to estimate the effect on open and closed loop control a suitable model is needed. One promising candidate is the Preisach independent domain hysteresis model that is characterized by the congruent minor loop and wiping out properties. Comparable minor loop and decaying oscillation test

Declan Hughes; John T. Wen

1995-01-01

55

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

56

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

57

Extending hysteresis operators to spaces of piecewise continuous functions  

E-print Network

.D. MAWBY Department of Mathematical Sciences, University of Bath, Bath BA2 7AY, United Kingdom Email: hl@maths.bath.ac.uk, am@maths.bath.ac.uk Abstract: We consider continuous-time hysteresis operators, de#12;ned of \\hysteresis" loops. The memory e#11;ects exhibited by hysteresis phenomena are rate independent in contrast

Bath, University of

58

Multicritical Dynamic Phase Diagrams and Dynamic Hysteresis Loops in a Mixed Spin-2 and Spin-5/2 Ising Ferrimagnetic System with Repulsive Biquadratic Coupling: Glauber Dynamic Approach  

NASA Astrophysics Data System (ADS)

The stationary states of the kinetic mixed spin-2 and spin-5/2 Ising ferrimagnetic system with repulsive biquadratic coupling are examined within a mean-field approach under the presence of a time varying (sinusoidal) magnetic field. We employ Glauber-type stochastic dynamics to construct a set of coupled mean-field dynamic equations, and we solve these equations to find the phases in the system. We also investigate the thermal behavior of the dynamic order parameters to characterize the nature (continuous or discontinuous) of the dynamic phase transitions (DPTs) and obtain the DPT points. The phase diagrams are presented in the reduced magnetic field amplitude and reduced temperature plane, and a comparison is made with the results of other kinetic mixed spin systems. We also study the behavior of the dynamic magnetic hysteresis and investigate the effects of the frequency on hysteresis properties, and we find the results are in good agreement with some previous theoretical and experimental works.

Erta?, Mehmet; Keskin, Mustafa; Deviren, Bayram

2012-03-01

59

The hysteresis motor-advances whick permit economical fractional horsepower ratings  

Microsoft Academic Search

The theory of the development of torque in a hysteresis motor is analyzed from both the hysteresis lag angle and total loop energy points of view. A new development, comprising the use of a closed slot stator in co-operation with a hysteresis rotor, which permits building hysteresis motors of high power output at high efficiency is explained qualitatively and supplemented

Herbert C. Roters

1947-01-01

60

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

61

Hysteresis in a quantized superfluid 'atomtronic' circuit.  

PubMed

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). PMID:24522597

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

2014-02-13

62

The Hysteresis Motor with an Anisotropic Rotor  

Microsoft Academic Search

An analysis of the hysterezis motor with anisotropic rotor has been carried out. Using an elliptical approximation for the hysteresis loop, the expression of the magnetic vector potential in the anisotropic region of the rotor has been obtained both in the case of a stator surface carrying a curent sheet with sinusoidal variation, and in the case of a rotor

N. Galan

1987-01-01

63

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

64

Optimizing the Jiles-Atherton model of hysteresis by a genetic algorithm  

Microsoft Academic Search

Modeling magnetic components for simulation in electric circuits requires an accurate model of the hysteresis loop of the core material used. It is important that the parameters extracted for the hysteresis model be optimized across the range of operating conditions that may occur in circuit simulation. This paper shows how to extract optimal parameters for the Jiles-Atherton model of hysteresis

Peter R. Wilson; J. Neil Ross; Andrew D. Brown

2001-01-01

65

Analysis of hysteresis motor using finite element method and magnetization-dependent model  

Microsoft Academic Search

In this paper, finite element analysis (FEA) of a hysteresis motor using a magnetization-dependent model is presented. The hysteresis loop in the hysteresis ring is calculated from the maximum flux density which is obtained by the FEA. The proposed method is applied to a sample motor and the simulation result shows a very good agreement with the experimental one. Various

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

2000-01-01

66

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

67

Hysteresis in Metal Hydrides.  

ERIC Educational Resources Information Center

This paper describes a reproducible process where the irreversibility can be readily evaluated and provides a thermodynamic description of the important phenomenon of hysteresis. A metal hydride is used because hysteresis is observed during the formation and decomposition of the hydride phase. (RH)

Flanagan, Ted B., And Others

1987-01-01

68

Revisiting the hysteresis effect in surface energy budgets  

NASA Astrophysics Data System (ADS)

The hysteresis effect in diurnal cycles of net radiation Rn and ground heat flux G0 has been observed in many studies, while the governing mechanism remains vague. In this study, we link the phenomenology of hysteresis loops to the wave phase difference between the diurnal evolutions of various terms in the surface energy balance. Rn and G0 are parameterized with the incoming solar radiation and the surface temperature as two control parameters of the surface energy partitioning. The theoretical analysis shows that the vertical water flux W and the scaled ratio As*>/AT* (net shortwave radiation to outgoing longwave radiation) play crucial roles in shaping hysteresis loops of Rn and G0. Comparisons to field measurements indicate that hysteresis loops for different land covers can be well captured by the theoretical model, which is also consistent with Camuffo-Bernadi formula. This study provides insight into the surface partitioning and temporal evolution of the energy budget at the land surface.

Sun, Ting; Wang, Zhi-Hua; Ni, Guang-Heng

2013-05-01

69

Theory of the hysteresis loop in ferromagnets  

E-print Network

summarize some of the results found in Refs. 19 and 14: Since the disorder is weak @see Eq. ~3!#, the interface is essentially flat on length scales L!Lc , where Lc?lS G hl D 2/ ~ 42D ! @l ~4! is the so-called Larkin length. On larger scales... summarize some of the results found in Refs. 19 and 14: Since the disorder is weak @see Eq. ~3!#, the interface is essentially flat on length scales L!Lc , where Lc?lS G hl D 2/ ~ 42D ! @l ~4! is the so-called Larkin length. On larger scales...

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

1999-01-01

70

Torque calculation of hysteresis motor using vector hysteresis model  

Microsoft Academic Search

This paper presents how to determine the thickness of the hysteresis ring of hysteresis motor using the finite element method combined with a vector hysteresis model. From the magnitude and direction of the magnetic field intensity, the magnetization of each ring element is calculated by the vector hysteresis model and the torque can be obtained from the vector sum of

Sun-Ki Hong; Kong-Kyu Kim; Hyeong-Seok Kim; Hyun-Kyo Jung

2000-01-01

71

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

72

Hysteresis phenomenon in turbulent convection  

E-print Network

Coherent large-scale circulations of turbulent thermal convection in air have been studied experimentally in a rectangular box heated from below and cooled from above using Particle Image Velocimetry. The hysteresis phenomenon in turbulent convection was found by varying the temperature difference between the bottom and the top walls of the chamber (the Rayleigh number was changed within the range of $10^7 - 10^8$). The hysteresis loop comprises the one-cell and two-cells flow patterns while the aspect ratio is kept constant ($A=2 - 2.23$). We found that the change of the sign of the degree of the anisotropy of turbulence was accompanied by the change of the flow pattern. The developed theory of coherent structures in turbulent convection (Elperin et al. 2002; 2005) is in agreement with the experimental observations. The observed coherent structures are superimposed on a small-scale turbulent convection. The redistribution of the turbulent heat flux plays a crucial role in the formation of coherent large-scal...

Eidelman, A; Kleeorin, N; Markovich, A; Rogachevskii, I

2006-01-01

73

STP Hysteresis Program  

NSDL National Science Digital Library

The STP Hysteresis program is a Monte Carlo simulation of a two-dimensional Ising model demonstrating that the magnetization does not immediately change when the external magnetic field is changed. The default is a lattice of linear dimension L=32 (for a total of N=L^2 spins), a temperature T=1.8 and an external field that changes from H=1 to H=-1 and then returns to its original value. STP Hysteresis is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double clicking the stp_Hysteresis.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-03-13

74

A constitutive model for the frequency dependence of magnetic hysteresis  

NASA Astrophysics Data System (ADS)

The magnetic properties of materials are characterized by the variation of flux density with magnetic field. The hysteresis loop is generally dependent on the frequency of excitation. It is well known that the dependence is attributed to the effects of eddy current loss and anomalous (excess) loss. The present work deals with a new approaching method to model the frequency dependence of magnetic hysteresis within the framework of internal state variable theory, the fundamental structure of which is originally based on viscoplasticity theory in continuum mechanics. The hysteresis equations are formulated to be consistent with the general principles of irreversible thermodynamics with internal variables.

Ho, Kwangsoo

2014-10-01

75

Wetting Hysteresis at the Molecular Scale  

NASA Technical Reports Server (NTRS)

The motion of a fluid-fluid-solid contact line on a rough surface is well known to display hysteresis in the contact angle vs. velocity relationship. In order to understand the phenomenon at a fundamental microscopic level, we have conducted molecular dynamics computer simulations of a Wilhelmy plate experiment in which a solid surface is dipped into a liquid bath, and the force-velocity characteristics are measured. We directly observe a systematic variation of force and contact angle with velocity, which is single-valued for the case of an atomically smooth solid surface. In the microscopically rough case, however, we find (as intuitively expected) an open hysteresis loop. Further characterization of the interface dynamics is in progress.

Jin, Wei; Koplik, Joel; Banavar, Jayanth R.

1996-01-01

76

An Analysis of the Hysteresis Motor II-The Circumferential-Flux Machine  

Microsoft Academic Search

Part I of this paper presented an analysis of an idealized polyphase hysteresis machine having a radial-flux type of rotor. In this Part II, a hysteresis machine with a circumferential-flux type of rotor is analyzed. Using a rectangular loop approximation to the B-H characteristic of the hysteresis material, the flux density distribution in the machine is found and an equivalent

M. A. Copeland; G. R. Slemon

1964-01-01

77

Compensator design for hysteresis of a stacked PZT actuator using a congruency-based hysteresis model  

NASA Astrophysics Data System (ADS)

This paper proposes a rate-independent hysteresis compensator for a stacked PZT (lead zirconate titanate) actuator. From a congruency-based hysteresis (CBH) model which is derived from the inherent properties of this actuator, especially the congruency, a feedforward compensator associated with it is developed. The formulation of the proposed compensator is based on an assumption that the inverse operator also possesses the same properties as the CBH model does. This implies that the compensator also possesses properties such as the wiped-out loop closing between the consecutive control points and congruency. Consequently, the expressions for the compensator can be conducted by exploiting the equations for the CBH model in two cases of monotonic increase and monotonic decrease of input excitation. In order to assess the performance of the compensator, several experiments in both open-loop and closed-loop controls are undertaken. In the open-loop control experiment, the performance of the feedforward compensator using the CBH model is compared with the classical Preisach model-based one in three cases of reference waveforms. In the closed-loop control experiment, the proposed compensator is incorporated into a PID (proportional-integral-derivative) control system and the performance of this integrated system is then evaluated and compared to that of the PID with and without compensator.

Nguyen, Phuong-Bac; Choi, Seung-Bok

2012-01-01

78

Isochronal annealing studies of a plastically deformed ferromagnetic metal using magnetic hysteresis measurements  

Microsoft Academic Search

An experimental study has been made of magnetic hysteresis in plastically deformed and annealed gadolinium (Gd) metal as a function of annealing temperature. Seven plastically deformed samples were annealed at temperatures ranging from 155° to 916°C; major and minor magnetic hysteresis loops of these seven samples plus one as-deformed sample were examined. The results are discussed in terms of the

Frederick Milstein; John A. Baldwin; Timothy W. James

1973-01-01

79

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

E-print Network

Cochlear hysteresis: Observation with low-frequency modulated distortion product otoacousticTr revealed a sigmoid-shaped hysteresis loop with counterclockwise traversal. Physiologic indices by the voltage- dependent conformational change of motor proteins, e.g., prestin Liberman et al., 2002 , residing

Allen, Jont

80

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

81

Computerized magnetic test and evaluation of hysteretic materials [hysteresis motors  

Microsoft Academic Search

Techniques are described which enable highly nonlinear hysteretic materials to be fully characterized. Major hysteresis loops and minor trajectories are presented for one particular material sample. Test time is reduced to less than 10s, ensuring that heating effects in the ring sample are negligible. The method is appropriate for detailed material investigation for design or development applications. It is recognized,

P. T. Jowett; D. I. MacInnes

1989-01-01

82

Roughness dependent magnetic hysteresis of a few monolayer thick Fe films on Au(001)  

Microsoft Academic Search

We have studied quantitatively the surface and interface roughness of Fe films in a new monolayer regime on an Au(001) surface using the high-resolution low-energy electron diffraction technique. The hysteresis loops of those films were also measured in situ by the surface magneto-optical kerr effect technique. A correlation between the shape of hysteresis loops and the roughness of films was

Y.-L. He; G.-C. Wang

1994-01-01

83

Roughness dependent magnetic hysteresis of a few monolayer thick Fe films on Au(001)  

Microsoft Academic Search

We have studied quantitatively the surface and interface roughness of Fe films in a few monolayer regime on an Au(001) surface using the high-resolution low-energy electron diffraction technique. The hysteresis loops of those films were also measured insitu by the surface magneto-optical kerr effect technique. A correlation between the shape of hysteresis loops and the roughness of films was observed.

Y.-L. He; G.-C. Wang

1994-01-01

84

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

85

Thermal hysteresis proteins.  

PubMed

Extreme environments present a wealth of biochemical adaptations. Thermal hysteresis proteins (THPs) have been found in vertebrates, invertebrates, plants, bacteria and fungi and are able to depress the freezing point of water (in the presence of ice crystals) in a non-colligative manner by binding to the surface of nascent ice crystals. The THPs comprise a disparate group of proteins with a variety of tertiary structures and often no common sequence similarities or structural motifs. Different THPs bind to different faces of the ice crystal, and no single mechanism has been proposed to account for THP ice binding affinity and specificity. Experimentally THPs have been used in the cryopreservation of tissues and cells and to induce cold tolerance in freeze susceptible organisms. THPs represent a remarkable example of parallel and convergent evolution with different proteins being adapted for an anti-freeze role. PMID:11240367

Barrett, J

2001-02-01

86

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

87

Hysteresis in Granular Media Subjected to Axisymmetrical Rotation  

NASA Astrophysics Data System (ADS)

In this work we have studied the hysteretic behavior for the mean slope of the free surface of noncohesive granular media under axisymmetricalrotation. In order to study the hysteresis loop the relationship between theaverage slope of the free surface (most important measurable quantity) andthe Froude number has been established. Differences between experiments andtheoretical predictions are also shown. Theory predicts that hysteresis mustdisappear as the friction coefficient µ of the granular materialreaches unity. However, this condition could not be reached experimentallyusing tapioca (where µ˜1), due to the important difference betweenthe angle of internal friction and the angle of repose for small containers.

Medina, Abraham; Treviño, Casay

1999-06-01

88

Mathematical Models of Hysteresis (Dynamic Problems in Hysteresis).  

National Technical Information Service (NTIS)

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 magne...

I. Mayergoyz

2006-01-01

89

Unconventional dynamic hysteresis in a periodic assembly of paramagnetic colloids.  

PubMed

Dynamic hysteresis phenomena are widespread in physical sciences and describe the complex behavior of systems driven out of equilibrium by a periodic forcing. We use here paramagnetic colloids above a stripe-patterned garnet film as the model system to study dynamic hysteresis, the latter induced when the particles are periodically translated by an oscillating magnetic field. In contrast to the expected behavior for a bistable system, we observe that the area of the hysteresis loop decreases by increasing the driving frequency and reduces to zero for frequencies higher than 5-7s(-1). To explain the experimental results, we develop a simple model based on an overdamped Brownian particle driven by a periodic potential with an oscillating amplitude. PMID:23848669

Tierno, Pietro; Johansen, Tom H; Sancho, J M

2013-06-01

90

An Energy-Based Hysteresis Model for Magnetostrictive Transducers  

NASA Technical Reports Server (NTRS)

This paper addresses the modeling of hysteresis in magnetostrictive transducers. This is considered in the context of control applications which require an accurate characterization of the relation between input currents and strains output by the transducer. This relation typically exhibits significant nonlinearities and hysteresis due to inherent properties of magnetostrictive materials. The characterization considered here is based upon the Jiles-Atherton mean field model for ferromagnetic hysteresis in combination with a quadratic moment rotation model for magnetostriction. As demonstrated through comparison with experimental data, the magnetization model very adequately quantifies both major and minor loops under various operating conditions. The combined model can then be used to accurately characterize output strains at moderate drive levels. The advantages to this model lie in the small number (six) of required parameters and the flexibility it exhibits in a variety of operating conditions.

Calkins, F. T.; Smith, R. C.; Flatau, A. B.

1997-01-01

91

Sinusoidal input describing function for hysteresis followed by elementary backlash  

NASA Technical Reports Server (NTRS)

The author proposes a new sinusoidal input describing function which accounts for the serial combination of hysteresis followed by elementary backlash in a single nonlinear element. The output of the hysteresis element drives the elementary backlash element. Various analytical forms of the describing function are given, depending on the a/A ratio, where a is the half width of the hysteresis band or backlash gap, and A is the amplitude of the assumed input sinusoid, and on the value of the parameter representing the fraction of a attributed to the backlash characteristic. The negative inverse describing function is plotted on a gain-phase plot, and it is seen that a relatively small amount of backlash leads to domination of the backlash character in the describing function. The extent of the region of the gain-phase plane covered by the describing function is such as to guarantee some form of limit cycle behavior in most closed-loop systems.

Ringland, R. F.

1976-01-01

92

A generalized Prandtl-Ishlinskii model for characterizing the hysteresis and saturation nonlinearities of smart actuators  

NASA Astrophysics Data System (ADS)

Smart actuators, such as shape memory alloy (SMA) and magnetostrictive actuators, exhibit saturation nonlinearity and hysteresis that may be symmetric or asymmetric. The Prandtl-Ishlinskii model employing classical play operators has been used to describe the hysteresis properties of smart actuators that are symmetric in nature. In this study, the application of a generalized play operator capable of characterizing symmetric as well as asymmetric hysteresis properties with output saturation is explored in formulating a generalized Prandtl-Ishlinskii model. The generalized play operator employs different envelope functions under increasing and decreasing inputs to describe asymmetric and saturated output-input hysteresis loops. The validity of the proposed generalized model to characterize symmetric and asymmetric hysteresis properties is demonstrated by comparing the model responses with the measured major and minor hysteresis loops of three different types of actuator, namely SMA, magnetostrictive, and piezoceramic actuators. The simulation results suggest that the proposed generalized Prandtl-Ishlinskii model can be directly applied for modeling the hysteresis loops of different smart actuators together with the output saturation.

Janaideh, Mohammad Al; Rakheja, Subhash; Su, Chun-Yi

2009-04-01

93

Hysteresis Model for Piezoceramic Materials.  

National Technical Information Service (NTIS)

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 ...

R. C. Smith, Z. Ounaies

1999-01-01

94

Detection of multistability, bifurcations, and hysteresis in a large class of biological  

E-print Network

, double- negative-feedback loop (which, in some regards, is equivalent to a positive-feedback loop) (Fig feedback does not guarantee bistability. A standard graph- ical test, termed phase plane analysis, canDetection of multistability, bifurcations, and hysteresis in a large class of biological positive

Chen, Kuang-Yu

95

Compensation of rate-dependent hysteresis nonlinearities in a magnetostrictive actuator using an inverse Prandtl-Ishlinskii model  

NASA Astrophysics Data System (ADS)

Magnetostrictive actuators invariably exhibit hysteresis nonlinearities that tend to become significant under high rates of inputs, and could cause oscillations and error in the micro-positioning tasks. This study presents a methodology for compensation of hysteresis nonlinearity in a magnetostrictive actuator subject to a wide range of input rates in an open-loop manner. The hysteresis compensation is attained through application of an inverse rate-dependent Prandtl-Ishlinskii model formulated on the basis of the rate-dependent Prandtl-Ishlinskii hysteresis model and laboratory-measured hysteresis properties of the magnetostrictive actuator under inputs at frequencies up to 200 Hz. The effectiveness of the inverse rate-dependent Prandtl-Ishlinskii model compensator for mitigating the major and minor loop hysteresis nonlinearities is demonstrated through simulation results and hardware-in-the-loop laboratory measurements of a magnetostrictive actuator (stroke ±50 ?m) under inputs in the 1-200 Hz frequency range. Both the simulation and experimental results revealed reduction of peak hysteresis from 4.7 to 0.645 ?m, when the proposed inverse rate-dependent model is applied as a feedforward hysteresis compensator, which occurred under excitations at the lowest frequency of 1 Hz. The results suggest that the inverse Prandtl-Ishlinskii model could provide hysteresis compensation under different rates of inputs in a simple and effective manner.

Aljanaideh, Omar; Janaideh, Mohammad Al; Rakheja, Subhash; Su, Chun-Yi

2013-02-01

96

Transient Performance of Hysteresis Motors with Ferrite Magnets  

Microsoft Academic Search

This paper presents a general picture of basic features of the transient performance of circumferential-flux hysteresis motors when ferrite magnets (Ceramic–8) are oriented within the rotor. Based on the parallelogram approximation of the B-H loops of the magnetic materials, a mathematical model to predict the transient performance of such motors is given. This simple analysis is used in demonstrating various

A. M. Osheiba; M. A. Rahman

1986-01-01

97

ASYNCHRONOUS PERFORMANCES OF HYSTERESIS MOTORS UNDER UNBALANCED CONDITIONS  

Microsoft Academic Search

The torque-speed curves of an hysteresis motor under unbalanced conditions are computed by a numerical method. The magnetic characteristic of the rotor ring is represented by the Preisach-Néel's model. This method takes into account the minor loops which appear on the B(H) characteristic in the case under consideration. Computed and experimental curves are compared. This work shows that eddy currents

J. PERARD; M. POLOUJADOFF

1977-01-01

98

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

99

Studies on dielectric hysteresis of ferroelectric sodium vanadate, rubidium vanadate, cesium vanadate and their solid solutions  

Microsoft Academic Search

The dielectric hysteresis property of sodium vanadate, rubidium vanadate, cesium vanadate and their solid solutions has been\\u000a studied in the temperature range covering their transition points. The hysteresis loop method is used for coercive field measurements.\\u000a It was observed that the coercive field decreases with increasing temperature, and that it also decreases with increasing\\u000a sodium concentration in the solid solutions

V V Patil; A P Kashid; S H Chavan

1989-01-01

100

An analytical solution for the field of a hysteresis motor based on complex permeability  

Microsoft Academic Search

A closed-form solution for the electromagnetic field distribution inside a hysteresis motor is presented. The solution is based upon Maxwell's field equations, considering the case of a circumferential-flux-type machine at synchronous speed. A hysteresis loop in the shape of an inclined ellipse is adopted. The application of the complex permeability concept to space rotating vectors is explained. A new form

Farouk A. A. Zaher

1990-01-01

101

Hysteresis in quantized vortex shedding  

NASA Astrophysics Data System (ADS)

It is shown using numerical simulations that flow patterns around an obstacle potential moving in a superfluid exhibit hysteresis. In a certain velocity region, there is a bistability between stationary laminar flow and periodic vortex shedding. The bistability exists in two- and three-dimensional systems.

Kadokura, Tsuyoshi; Yoshida, Jun; Saito, Hiroki

2014-07-01

102

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

103

The role of hysteresis in propagating acoustic wave in porous materials  

NASA Astrophysics Data System (ADS)

Hysteresis and end-point memory are universal behaviors of porous materials including rock, sandstone, soil, sediment, ceramic, and some cracked materials. Recently, there have been growing interests in studying hysteresis and linking this static property to dynamic behaviors, particularly in modeling nonlinear acoustic phenomena in porous materials. This study aims at exploring the role of hysteresis in propagation of an acoustic wave in soils. A modified triaxial cell was used to measure stress/strain and sound speed/strain relationships in a triaxial test. Soil samples were subjected to a load stress path that was designed to undergo a series of meso-scopic unload-reload stress cycles with axial strain in the range of 10Exp(-5)-10Exp(-4). It is found that the slope of the hysteresis loop is linearly correlated with the dynamic elastic modulus, which implies that the fluctuation of acoustic pressure may create micro-hysteresis loops that make the dynamic elastic modulus higher than static elastic modulus. This discovery may lead to a correction in the classical equation of state by adding a hysteresis term. [Work supported by the U.S. Department of Agriculture.

Lu, Zhiqu; Sabatier, James

2004-10-01

104

Influence of interfacial dislocations on hysteresis loops of ferroelectric films  

E-print Network

of domains with reversed polariza- tion, and domain wall mobility.3­9 Defects such as disloca- tions, space transition tem- peratures and domain structures in ferroelectric films and superlattices.20­22 It has also transition temperature and leads to the preferen- tial formation of ferroelectric domains around misfit

Chen, Long-Qing

105

Polarization Reversal in the Barium Titanate Hysteresis Loop  

Microsoft Academic Search

In the presence of an opposing field the polarization of tetragonal BaTiO3 reverses itself. Devonshire's phenomenological treatment shows that in a sufficiently large opposing field the original direction of polarization becomes unstable. The values of commonly observed coercive fields are much smaller than this, and the polarization actually reverses while the initial state is still metastable. The observed coercive field

R. Landauer; D. R. Young; M. E. Drougard

1956-01-01

106

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

NASA Astrophysics Data System (ADS)

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; Keskin, Mustafa

2014-09-01

107

Magnetic hysteresis of p(+) and He-3(2+) irradiated melt-textured YBa2Cu3O(7-delta)  

NASA Technical Reports Server (NTRS)

We have measured the magnetic hysteresis loops and temperature dependent trapped fields in melt-textured YBa2Cu3O(7-delta) samples before and after p(+) and He-3(2+) irradiation using a Hall effect magnetometer (HEM) as well as a commercial vibrating sample magnetometer (VSM). For proper He-3(2+) fluence, the critical current density may be enhanced by a factor of 10. Calculations based on various critical state models show that before the irradiation, the hysteresis loops can be well accounted for by a critical current density of a modified power law field dependence. After the irradiation, the best fit has been achieved by using an exponential form. Jc and its field dependence deduced from HEM hysteresis loops are in good agreement with those deduced from the VSM loops, suggesting that the Hall effect magnetometer can be conveniently used to characterize bulk high Tc oxide superconductors.

Song, S. N.; Liu, J.; Chen, I. G.; Weinstein, Roy

1992-01-01

108

Effects of Hysteresis Between Maximum CME Speed Index and Typical Solar Activity Indicators During Cycle 23  

NASA Astrophysics Data System (ADS)

Using the smoothed time series of maximum CME speed index for solar cycle 23, it is found that this index, analyzed jointly with six other solar activity indicators, shows a hysteresis phenomenon. The total solar irradiance, coronal index, solar radio flux (10.7 cm), Mg ii core-to-wing ratio, sunspot area, and H? flare index follow different paths for the ascending and the descending phases of solar cycle 23, while a saturation effect exists at the maximum phase of the cycle. However, the separations between the paths are not the same for the different solar activity indicators used: the H? flare index and total solar irradiance depict broad loops, while the Mg ii core-to-wing ratio and sunspot area depict narrow hysteresis loops. The lag times of these indices with respect to the maximum CME speed index are discussed, confirming that the hysteresis represents a clue in the search for physical processes responsible for changing solar emission.

Özgüç, A.; Kilcik, A.; Rozelot, J. P.

2012-12-01

109

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

110

Studies on dielectric and hysteresis properties of undoped and aluminium oxide doped ferroelectric cesium vanadate  

Microsoft Academic Search

The effect of aluminium doping, as an acceptor impurity on the polycrystalline cesium vanadate has been studied in the temperature range covering their transition points. The dielectric constant is measured by 'comparison of capacities' while the coercive field is evaluated using hysteresis loop. It is seen that the dielectric constant as well as the coercive field are remarkably depending on

S. P. Rasal; V. V. Patil; A. J. Kulkarni; S. H. Chavan

1991-01-01

111

Performance predictions for large hysteresis motors  

Microsoft Academic Search

This paper examines the possibilities of designing large, integral-horsepower hysteresis motors to have efficiency and power factor comparable with that of induction motors. Scaling techniques are used, together with a previously published analytical method, to scale up an existing laboratory hysteresis motor of 3 kW rating. The resulting design for a 200 kW hysteresis motor is predicted to have an

G. R. Slemon; R. D. Jackson; M. A. Rahman

1977-01-01

112

Hysteresis and Wavenumber Vacillation in Unstable Baroclinic Flows  

NASA Technical Reports Server (NTRS)

Hysteresis and wavenumber vacillation are studied numerically in a weakly stratified quasigeostrophic model. In general, the amplitude of the most unstable wave increases, as the flow becomes more unstable. When the wave becomes saturated, the next longer wave will grow at the expanse of the most unstable wave and becomes the dominant wave. However, once the longwave state is established, it may remain in that regime even as the instability is decreased beyond the threshold where it first developed, thus constituting a hysteresis loop. In a highly unstable case, the flow may not show a preference for any single wave. Instead, the dominant wave aperiodically varies among several long waves. This phenomenon is known as wavenumber vacillation. Hysteresis is further examined in terms of eddy heat flux. It is shown that total eddy heat flux increases as the flow becomes more unstable, but displays a sharp drop when transition to a longer wave occurs. However, in a longwave state, the heat flux always decreases with decreasing instability even pass the threshold when wave transition first occurs.

Chou, Shih-Hung; Goodman, H. Michael (Technical Monitor)

2001-01-01

113

Hysteresis variations of (Pb, La)(Zr, Ti)O3 capacitors baked in a hydrogen atmosphere  

Microsoft Academic Search

Baking (Pb, La)(Zr, Ti)O3 capacitors in a hydrogen atmosphere causes a significant loss of remanent polarization even at 150 °C. The hysteresis variations depend on the polarization states during baking. The hysteresis loop showed voltage shifts when the capacitor was polarized before baking, whereas it became a cramped shape when the baking was carried out on a virgin capacitor. Although

T. Tamura; K. Matsuura; H. Ashida; K. Kondo; S. Otani

1999-01-01

114

Comparative solute–discharge hysteresis analysis for an urbanized and a ‘control basin’ in the Georgia (USA) Piedmont  

Microsoft Academic Search

Solute–discharge hysteresis (C\\/Q) relationships were investigated in an urbanized (Peachtree Creek) and a less-urbanized ‘control’ basin (Sweetwater Creek, SWC) within the Atlanta metropolitan region of the Georgia Piedmont. C\\/Q hysteresis loops for the nine parameters (pH, specific conductance, dissolved silica, calcium, magnesium, sodium, bicarbonate, sulfate and chloride) representative of urban storm flow were almost exclusively characterized by clockwise rotation and

Seth Rose

2003-01-01

115

Study on the hunting in high speed hysteresis motors due to the rotor hysteresis material  

Microsoft Academic Search

Hysteresis motors behave very much like to classical synchronous motors, except that the motor magnetic pole definition varies slightly with torque. This paper presents a study on the hunting of a radial-flux type, high speed hysteresis motor caused by the hysteresis material of the rotor. Firstly, a nonlinear dynamic model of the PWM-controlled hysteresis motor drive is developed in d-q

H. R. Soroush; A. R. Rahmati; H. Moghbelli; A. Vahedi; A. H. Niasar

2009-01-01

116

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

117

Steady-State Performance of Polyphase Hysteresis-Reluctance Motors  

Microsoft Academic Search

It is well known that the hysteresis-reluctance motor produces a torque that combines hysteresis and reluctance effects. Consequently, the performance characteristics would be increased when compared to that of the plain hysteresis motor. This paper presents a new design of a hysteresis-reluctance rotor in which the magnetic saliency was created by cutting slots in the inside diameter of the hysteresis

M. A. Rahman; A. M. Osheiba

1986-01-01

118

Rate-dependent hysteresis losses in ensembles of magnetic nanoparticle clusters  

NASA Astrophysics Data System (ADS)

Hysteresis is ubiquitous in magnetic nanoparticle systems and understanding how it emerges from complex interactions and for different time scales is a long-standing issue in magnetism research. Understanding the phenomenon is most important for engineering magnetic nanoparticle structures of well-controlled properties in magnetic recording, hysteresis loss optimization in hyperthermia cancer treatment in biomedicine, or biological and chemical sensing, to name a few examples. In this work we address one of the general questions related to the influence of thermal activation processes on hysteresis loss. Employing large-scale computational modeling based on the master-equation framework we investigate the influence of dipolar interactions on thermal hysteresis loops in ensembles of magnetic nanoparticle chains and clusters. We show that the directional dependence of dipolar interactions results in enhanced or reduced hysteresis loss, depending on the distribution of particles' anisotropy axes and particle chain orientations with respect to the external field. Additional hysteresis loss reduction occurs in case of particle clusters due to possibility of the frustration phenomenon not present for topologically simpler chains.

Hovorka, Ondrej; Evans, Richard; Friedman, Gary; Chantrell, Roy

2012-02-01

119

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

120

Dynamic performance prediction of polyphase hysteresis motors  

Microsoft Academic Search

The dynamic performance characteristics of polyphase hysteresis motors are presented. A mathematical model to predict the starting and synchronization process of such motors under various operating conditions is given. The model offers a tool for studying the dynamic stability of the hysteresis motor for small-scale disturbances such as changes in load torque, supply voltage, and frequency. A parametric variation is

M. A. Rahman; ALI M. OSHEIBA

1990-01-01

121

Equivalent Circuit Modeling of Hysteresis Motors  

Microsoft Academic Search

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

J J Nitao; E T Scharlemann; B A Kirkendall

2009-01-01

122

Field Analysis of Polyphase Hysteresis Motor  

Microsoft Academic Search

A comprehensive theoretical field model has been developed for hysteresis motors. Using the stator current sheet technique, the motor field equations are rigoriously derived for the air gap and hysteresis ring regions. The analysis takes into account the contribution of the reaction field of rotor magnetization to the primary air gap field due to stator current sheets alone. Unlike induction

M. A. Rahman

1980-01-01

123

Analysis of a hysteresis motor with overexcitation  

Microsoft Academic Search

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

T. Kataoka; T. Ishikawa; T. Takahashi

1982-01-01

124

Thermohaline circulation hysteresis: A model intercomparison  

Microsoft Academic Search

We present results from an intercomparison of 11 different climate models of intermediate complexity, in which the North Atlantic Ocean was subjected to slowly varying changes in freshwater input. All models show a characteristic hysteresis response of the thermohaline circulation to the freshwater forcing; which can be explained by Stommel's salt advection feedback. The width of the hysteresis curves varies

Stefan Rahmstorf; Michel Crucifix; Andrey Ganopolski; Hugues Goosse; Igor Kamenkovich; Reto Knutti; Gerrit Lohmann; Robert Marsh; Lawrence A. Mysak; Zhaomin Wang; Andrew J. Weaver

2005-01-01

125

Lift hysteresis at stall as an unsteady boundary-layer phenomenon  

NASA Technical Reports Server (NTRS)

Analysis of rotating stall of compressor blade rows requires specification of a dynamic lift curve for the airfoil section at or near stall, presumably including the effect of lift hysteresis. Consideration of the magnus lift of a rotating cylinder suggests performing an unsteady boundary-layer calculation to find the movement of the separation points of an airfoil fixed in a stream of variable incidence. The consideration of the shedding of vorticity into the wake should yield an estimate of lift increment proportional to time rate of change of angle of attack. This increment is the amplitude of the hysteresis loop. An approximate analysis is carried out according to the foregoing ideas for a 6:1 elliptic airfoil at the angle of attack for maximum lift. The assumptions of small perturbations from maximum lift are made, permitting neglect of distributed vorticity in the wake. The calculated hysteresis loop is counterclockwise. Finally, a discussion of the forms of hysteresis loops is presented; and, for small reduced frequency of oscillation, it is concluded that the concept of a viscous "time lag" is appropriate only for harmonic variations of angle of attack with time at mean conditions other than maximum lift.

Moore, Franklin K

1956-01-01

126

New formulation of the Stoner-Wohlfarth hysteresis model and the identification problem  

NASA Astrophysics Data System (ADS)

A new formulation of the Stoner-Wohlfarth hysteresis model is introduced. This formulation simplifies the analysis of the model through the use of a diagram technique similar to the one employed by the Preisach model. It is shown that using the new formulation the identification problem can be posed in terms of an integral equation relating the switching field distribution to the set of vertical chords of symmetric minor hysteresis loops. Solution of this integral equation is discussed, and some limitations of the Stoner-Wohlfarth model are revealed.

Friedman, G.

1990-05-01

127

Modeling of dynamic hysteresis for grain-oriented laminations using a viscosity-based modified dynamic Jiles-Atherton model  

NASA Astrophysics Data System (ADS)

Grain-oriented (GO) materials exhibit arbitrary frequency-loss behaviors and anomalies in dynamic hysteresis loop shapes. Significant attempts have been made in the literature to approximate dynamic hysteresis loops using the dynamic Jiles-Atherton (JA) model based Bertotti's approach. Such a model is inefficient in accurate loss computation over a wide range of frequencies and in predictions of correct loop shapes. Moreover, the original static JA model also needs to be improved for accurate prediction of highly steep, gooseneck, and narrow-waist static loops of GO materials. An alternative approach based on magnetic viscosity provides flexibilities to handle indefinite frequency dependence of the losses and to control the anomalous loop shapes. This paper proposes a viscosity-based dynamic JA model which gives accurate prediction of dynamic loops of GO materials. A modified static JA model which considers crystalline and textured structures of GO materials is used to predict static hysteresis loops. The dynamic losses are included in the modified model using the field separation approach. The proposed model is validated using experimental measurements. The computed and measured dynamic loops are in close agreement in the frequency range of 1-200 Hz.

Baghel, A. P. S.; Shekhawat, S. K.; Kulkarni, S. V.; Samajdar, I.

2014-09-01

128

Percolation model of relative permeability hysteresis  

NASA Astrophysics Data System (ADS)

A mathematical model of relative permeability hysteresis in drainage and imbibition is constructed on the basis of percolation theory. It is shown that the results are in qualitatively agreement with experimental data.

Kadet, V. V.; Galechyan, A. M.

2013-05-01

129

Quantized hysteresis in a superfluid atomtronic circuit  

E-print Network

Atomtronics is an emerging interdisciplinary field that seeks new functionality by creating devices and circuits where ultra-cold atoms play a role analogous to the electrons in electronics. Hysteresis in atomtronic circuits may prove to be a crucial feature for the development of practical devices, just as it has in electronic circuits like memory, digital noise filters (e.g., Schmitt triggers), and magnetometers (e.g., superconducting quantum interference devices [SQUIDs]). Here we demonstrate quantized hysteresis in an atomtronic circuit: a ring of superfluid, dilute-gas, Bose-Einstein condenstate (BEC) obstructed by a rotating weak link. Hysteresis is as fundamental to superfluidity (and superconductivity) as quantized persistent currents, critical velocity, and Josephson effects, but has not been previously observed in any atomic-gas, superfluid BEC despite multiple theoretical predictions. By contrast, hysteresis is routinely observed in superconducting circuits, and it is essential in rf-SQUIDs. Superf...

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

2014-01-01

130

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

131

Hysteresis effects in Bose-Einstein condensates  

E-print Network

Here, we consider damped two-components Bose-Einstein condensates with many-body interactions. We show that, when the external trapping potential has a double-well shape and when the nonlinear coupling factors are modulated in time, hysteresis effects may appear under some circumstances. Such hysteresis phenomena are a result of the joint contribution between the appearance of saddle node bifurcations and damping effect.

Andrea Sacchetti

2010-06-16

132

PERFORMANCE OF HYSTERESIS PERMANENT MAGNET MOTORS  

Microsoft Academic Search

There is an increasing interest in using permanent magnet (PM) hysteresis motors because of their superior performances over the conventional hysteresis motors. Recent NdBFe magnets have the advantages of higher magnetic energy product and remanence. It can develop significant accelerating torque during run-up and synchronization with limited temperature tolerance. The application of the NdBFe magnets in electrical machines Is attracting

A. M. OSHEIBA; J. QIAN; M. A. RAHMAN

1989-01-01

133

Dynamic performance prediction of hysteresis motors  

Microsoft Academic Search

The dynamic performance characteristics of polyphase hysteresis motors are presented. A mathematical model, based on the d-q-axis theory, for predicting the starting and synchronization processes of such motors under various operating conditions is presented. The model offers a tool for studying the dynamic stability of the hysteresis motor for small-scale disturbances such as load torque, supply voltage, and frequency. Moreover,

M. A. Rahman; A. M. Osheiba

1989-01-01

134

Analytical Models for Polyphase Hysteresis Motor  

Microsoft Academic Search

Using parallelogram model to the B-H characteristic of the hysteresis material, general expressions for the terminal quantities of a polyphase hysteresis machine are derived. Steady-state equivalent circuit models are developed for both the synchronous and sub-synchronous modes of operation. A comprehensive analysis of rotor parasitic loss components and stator saturation effects is made and these are represented by suitable parameters

M. Azizur Rahman

1973-01-01

135

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

136

Spatial versus time hysteresis in damping mechanisms  

NASA Technical Reports Server (NTRS)

A description is given of continuing investigations on the task of estimating internal damping mechanisms in flexible structures. Specifically, two models for internal damping in Euler-Bernoulli beams are considered: spatial hysteresis and time hysteresis. A theoretically sound computational algorithm for estimation is described, and experimental results are discussed. It is concluded that both models perform well in the sense that they accurately predict response for the experiments conducted.

Banks, H. T.; Fabiano, R. H.; Wang, Y.; Inman, D. J.; Cudney, H., Jr.

1988-01-01

137

Magnetic hysteresis in natural materials. [chondrites, lunar samples and terrestrial rocks  

NASA Technical Reports Server (NTRS)

Magnetic hysteresis loops and the derived hysteresis ratios R sub H and R sub I are used to classify the various natural dilute magnetic materials. R sub I is the ratio of saturation isothermal remanence (I sub R) to saturation (I sub S) magnetization, and R sub H is the ratio of remanent coercive force (H sub R) to coercive force (H sub C). The R sub H and R sub I values depend on grain size, the characteristics of separate size modes in mixtures of grains of high and low coercivity, and the packing characteristics. Both R sub H and R sub I are affected by thermochemical alterations of the ferromagnetic fraction. Hysteresis loop constriction is observed in lunar samples, chondrite meteorites, and thermochemically altered basaltic rocks, and is due to mixtures of components of high and low coercivity. Discrete ranges of R sub H and R sub I for terrestrial and lunar samples and for chondrite meteorites provide for a classification of these natural materials based on their hysteresis properties.

Wasilewski, P. J.

1973-01-01

138

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

139

Hysteresis motor using magnetically anisotropic Fe-Cr-Co magnet  

Microsoft Academic Search

For the rotor ring of the hysteresis motor, semihard Alnico magnets have been almost applied until now. However, the hysteresis motor using Alnico magnets has several disadvantages. In order to improve the disadvantages of conventional hysteresis motors, the Fe-Cr-Co magnet steel with magnetic anisotropy is applied for hysteresis rotor ring. Magnetic anisotropy is used to cause large reluctance torque and

Tomotsugu Kubota; Genjiro Wakui; Minoru Itagaki

1998-01-01

140

Efficient Energyminimization in Finite-Difference Micromagnetics: Speeding up Hysteresis Computations  

E-print Network

We implement an efficient energy-minimization algorithm for finite-difference micromagnetics that proofs especially usefull for the computation of hysteresis loops. Compared to results obtained by time integration of the Landau-Lifshitz-Gilbert equation, a speedup of up to two orders of magnitude is gained. The method is implemented in a finite-difference code running on CPUs as well as GPUs. This setup enables us to compute accurate hysteresis loops of large systems with a reasonable computational efford. As a benchmark we solve the {\\mu}Mag Standard Problem #1 with a high spatial resolution and compare the results to the solution of the Landau-Lifshitz-Gilbert equation in terms of accuracy and computing time.

Abert, Claas; Bruckner, Florian; Satz, Armin; Suess, Dieter

2014-01-01

141

Efficient energy minimization in finite-difference micromagnetics: Speeding up hysteresis computations  

NASA Astrophysics Data System (ADS)

We implement an efficient energy-minimization algorithm for finite-difference micromagnetics that proofs especially useful for the computation of hysteresis loops. Compared to results obtained by time integration of the Landau-Lifshitz-Gilbert equation, a speedup of up to two orders of magnitude is gained. The method is implemented in a finite-difference code running on central processing units (CPUs) as well as graphics processing units (GPUs). This setup enables us to compute accurate hysteresis loops of large systems with a reasonable computational effort. As a benchmark, we solve the ?Mag standard problem #1 with a high spatial resolution and compare the results to the solution of the Landau-Lifshitz-Gilbert equation in terms of accuracy and computing time.

Abert, Claas; Wautischer, Gregor; Bruckner, Florian; Satz, Armin; Suess, Dieter

2014-09-01

142

Polarization-dependent asymmetric hysteresis behavior in ZnCrO layers  

NASA Astrophysics Data System (ADS)

A ZnCrO layer grown on a Pt (111)/Al2O3 (0001) substrate exhibits a lattice displacement-induced ferroelectric behavior due to a modulation in the lattice translation symmetry. The top-to-bottom Pt/ZnCrO/Pt structure shows asymmetric hysteresis loops in positive and negative voltage bias regions. This is attributed to a change in the Schottky emission rate due to the nonlinear polarization of the ZnCrO barrier. The characteristics of the hysteresis loops depend on the film-textures of ZnCrO, which vary with the oxygen partial pressure during the growth stage of the ZnCrO layers. The results suggest that ZnCrO has efficacy characteristics for applications in the non-volatile resistive-switching systems.

Lee, Youngmin; Kim, Deuk Young; Lee, Sejoon; Fu, Dejun

2012-06-01

143

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

144

The influence of laminar separation and transition on low Reynolds number airfoil hysteresis  

NASA Technical Reports Server (NTRS)

An experimental study of the Lissaman 7769 and Miley MO6-13-128 airfoils at low chord Reynolds numbers is presented. Although both airfoils perform well near their design Reynolds number of about 600,000, they each produce a different type of hysteresis loop in the lift and drag forces when operated below chord Reynolds numbers of 300,000. The type of hysteresis loop was found to depend upon the relative location of laminar separation and transition. The influence of disturbance environment and experimental procedure on the low Reynolds number airfoil boundary layer behavior is also presented. The use of potential flow solutions to help predict how a given airfoil will behave at low Reynolds numbers is also discussed.

Mueller, T. J.

1984-01-01

145

Inelastic compaction, dilation and hysteresis of sandstones under hydrostatic conditions  

NASA Astrophysics Data System (ADS)

Sandstones display non-linear and inelastic behaviour such as hysteresis when subjected to cyclic loading. We present three hydrostatic compaction experiments with multiple loading-unloading cycles on Berea and Darley Dale sandstones and explain their hysteretic behaviour using non-linear inelastic compaction and dilation. Each experiment included eight to nine loading-unloading cycles with increasing maximum pressure in each subsequent cycle. Different pressure-volumetric strain relations during loading and unloading were observed. During the first cycles, under relatively low pressures, not all of the volumetric strain is recovered at the end of each cycle whereas at the last cycles, under relatively high pressures, the strain is recovered and the pressure-volumetric strain hysteresis loops are closed. The observed pressure-volumetric strain relations are non-linear and the effective bulk modulus of the sandstones changes between cycles. Observations are modelled with two inelastic deformation processes: irreversible compaction caused by changes in grain packing and recoverable compaction associated with grain contact adhesion, frictional sliding on grains or frictional sliding on cracks. The irreversible compaction is suggested to reflect rearrangement of grains into a more compact mode as the maximum pressure increases. Our model describes the `inelastic compaction envelope' in which sandstone sample will follow during hydrostatic loading. Irreversible compaction occurs when pressure is greater than a threshold value defined by the `inelastic compaction envelope'.

Shalev, Eyal; Lyakhovsky, Vladimir; Ougier-Simonin, Audrey; Hamiel, Yariv; Zhu, Wenlu

2014-05-01

146

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.

147

Steady-State Performance of Polyphase Hysteresis-Reluctance Motors  

Microsoft Academic Search

It is well known that the hysteresis-reluctance motor produces a torque that is a combination of the hysteresis and reluctance effects. Consequently, the performance characteristics of a hysteresis-reluctance motor would be improved when compared to that of the plain hysteresis motor. This paper presents a new design of a hysteresis-reluctance rotor in which the magnetic saliency is created by cutting

M. A. Rahman; A. M. Osheiba

1986-01-01

148

Statistical mechanical origin of hysteresis in ferroelectrics  

NASA Astrophysics Data System (ADS)

Hysteresis in ferroelectric materials is a strong non-linear phenomenon, the origin of which has drawn considerable attention. Based on the hopping probability function of the lattice-center ion crossing the ferroelectric double-well potential, a statistical mechanical theory is proposed to model ferroelectric hysteresis behavior. The hopping probability function is obtained from the statistical distribution function of ions in energy space, which is derived from the mathematical permutation and combination of the occupy-states of lattice-center ion. The calculated hysteresis agrees well with experimental measurements. In particular, the model provides interesting explanations to the polarization current and the coercive field, which differ from traditional microscopic models and thermodynamic theories.

Yang, Feng; Hu, Guangda; Xu, Baixiang; Wu, Weibing; Yang, Changhong; Wu, Haitao

2012-08-01

149

Hysteresis critical point of nitrogen in porous glass: occurrence of sample spanning transition in capillary condensation.  

PubMed

To examine the mechanisms for capillary condensation and for capillary evaporation in porous glass, we measured the hysteresis critical points and desorption scanning curves of nitrogen in four kinds of porous glasses with different pore sizes (Vycor, CPG75A, CPG120A, and CPG170A). The shapes of the hysteresis loop in the adsorption isotherm of nitrogen for the Vycor and the CPG75A changed with temperature, whereas those for the CPG120A and the CPG170A remained almost unchanged with temperature. The hysteresis critical points for the Vycor and the CPG75A fell on the common line observed previously for ordered mesoporous silicas. On the other hand, the hysteresis critical points for the CPG120A and the CPG170A deviated appreciably from the common line. This strongly suggests that capillary evaporation of nitrogen in the interconnected and disordered pores of both the Vycor and the CPG75A follows a cavitation process at least in the vicinity of their hysteresis critical temperatures in the same way as that in the cagelike pores of the ordered silicas, whereas the hysteresis critical points in the CPG120A and the CPG170A have origin different from that in the cagelike pores. The desorption scanning curves for the CPG75A indicated the nonindependence of the porous domains. On the other hand, for both the CPG120A and the CPG170A, we obtained the scanning curves that are expected from the independent domain theory. All these results suggest that sample spanning transitions in capillary condensation and evaporation take place inside the interconnected pores of both the CPG120A and the CPG170A. PMID:19466781

Morishige, Kunimitsu

2009-06-01

150

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

151

AVERAGING PRINCIPLE FOR DIFFERENTIAL EQUATIONS WITH HYSTERESIS  

E-print Network

this approximation holds is inverse propor- tional to the rate of change of slow variables. The system is described on the systems with the classical Preisach nonlinearity. Key words: Averaging technique, Hysteresis, Sweeping to Boole Centre for Research in Informatics and Department of Applied Mathematics, University College Cork

Schellekens, Michel P.

152

AN ANALYSIS OF THE HYSTERESIS MOTOR  

Microsoft Academic Search

The analysis of the hysteresis motor Is undertaken on the basis of a “rectified” representation of its structure. Maxwell's equations and Poyntlng's theorem are used In order to obtain the dependency of the developed force on the physical parameters and dimensions of the machine. Three different limiting cases are studied and their characteristics computed

S. GAVRIL; A. MOR

1982-01-01

153

Hunting in hysteresis motors, impact of supply  

Microsoft Academic Search

Hunting in synchronous motor is the continuous speed oscillation with a frequency around 3 to 5 Hz which arises from voltage or load distortions. This oscillation descends with exponential trend-line to steady state relative lower amplitude. This paper presents an investigation of hunting when a synchronous hysteresis motor is supplied with non-ideal input voltage sources. For studying of machine performance

Ahmad Darabi; Mohamadreza Rafiei; Teimoor Ghanbari

2007-01-01

154

Equivalent Circuit Modeling of Hysteresis Motors.  

National Technical Information Service (NTIS)

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,...

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

2009-01-01

155

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

156

Design of hysteresis circuits using differential amplifiers  

NASA Technical Reports Server (NTRS)

Design equations for hysteresis circuit are based on the following assumptions: amplifier input impedance is larger than source impedance; amplifier output impedance is less than load impedance; and amplifier switches state when differential input voltage is approximately zero. Circuits are designed to any given specifications.

Cooke, W. A.

1971-01-01

157

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

158

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

159

Performance Calculation of High Temperature Superconducting Hysteresis Motor Using Finite Element Method  

NASA Astrophysics Data System (ADS)

Hysteresis motors being capable of producing a steady torque at low speeds and providing good starting properties at loaded condition became popular among different fractional horse power electrical motors. High temperature superconducting materials being intrinsically hysteretic are suitable for this type of motor. In the present work, performance study of a 2-pole, 50 Hz HTS hysteresis motor with conventional stator and HTS rotor has been carried out numerically using finite element method. The simulation results confirm the ability of the segmented HTS rotor with glued circular sectors to trap the magnetic field as high as possible compared to the ferromagnetic rotor. Also the magnetization loops in the HTS hysteresis motor are obtained and the corresponding torque and AC losses are calculated. The motor torque thus obtained is linearly proportional to the current which is the common feature of any hysteresis motor. Calculations of torques, current densities etc are done using MATLAB program developed in-house and validated using COMSOL Multiphysics software. The simulation result shows reasonable agreement with the published results.

Konar, G.; Chakraborty, N.; Das, J.

160

Modeling Loading/Unloading Hysteresis Behavior of Unidirectional C/SiC Ceramic Matrix Composites  

NASA Astrophysics Data System (ADS)

The loading/unloading tensile behavior of unidirectional C/SiC ceramic matrix composites at room temperature has been investigated. The loading/unloading stress-strain curve exhibits obvious hysteresis behavior. An approach to model the hysteresis loops of ceramic matrix composites including the effect of fiber failure during tensile loading has been developed. By adopting a shear-lag model which includes the matrix shear deformation in the bonded region and friction in the debonded region, the matrix cracking space and interface debonded length are obtained by matrix statistical cracking model and fracture mechanics interface debonded criterion. The two-parameter Weibull model is used to describe the fiber strength distribution. The stress carried by the intact and fracture fibers on the matrix crack plane during unloading and subsequent reloading is determined by the Global Load Sharing criterion. Based on the damage mechanisms of fiber sliding relative to matrix during unloading and subsequent reloading, the unloading interface reverse slip length and reloading interface new slip length are obtained by the fracture mechanics approach. The hysteresis loops of unidirectional C/SiC ceramic matrix composites corresponding to different stress have been predicted.

Longbiao, Li; Yingdong, Song; Youchao, Sun

2013-08-01

161

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

162

Reduction of hysteresis in PI-controlled systems  

SciTech Connect

Motorized dampers and valves generally possess some hysteresis. Hysteresis may result in poor repeatability of experimental data. It also may result in the deviation of a response of a proportional integral (PI) controlled system from its target response and in hunting. In some applications, it may be desirable to reduce the effects of hysteresis. A method to reduce the effects of hysteresis is presented here. This method is based on software, not hardware, modification.

Krakow, K.I. [Concordia Univ., Montreal, Quebec (Canada). Dept. of Mechanical Engineering

1998-10-01

163

A Free Energy Model for Hysteresis in Ferroelectric Materials  

E-print Network

A Free Energy Model for Hysteresis in Ferroelectric Materials Ralph C. Smith Stefan Seelecke.ncsu.edu Abstract This paper provides a theory for quantifying the hysteresis and constitutive nonlinearities in#ects, and extreme electromechanical sensitivity, also produce varying degrees of hysteresis and constitutive

164

A Free Energy Model for Hysteresis in Ferroelectric Materials  

E-print Network

A Free Energy Model for Hysteresis in Ferroelectric Materials Ralph C. Smith Stefan Seelecke.ncsu.edu Abstract This paper provides a theory for quantifying the hysteresis and constitutive nonlinearities in, and extreme electromechanical sensitivity, also produce varying degrees of hysteresis and constitutive

165

EXPERIMENTAL MEASUREMENTS OF CAPILLARY PRESSURE AND RELATIVE PERMEABILITY HYSTERESIS  

Microsoft Academic Search

Capillary pressure and relative permeability hysteresis have been investigated on core samples with different wetting characteristics. The relative permeability and capillary pressure curves depend on the direction of saturation changes and on the maximum and minimum achieved saturations. A conceptual model to explain the hysteresis trends in both the relative permeability and capillary pressure is presented. The model attributes hysteresis

Shehadeh K. Masalmeh

166

Torque meter aids study of hysteresis motor rings  

NASA Technical Reports Server (NTRS)

Torque meter, simulating hysteresis motor operation, allows rotor ring performance characteristics to be analyzed. The meter determines hysteresis motor torque and actual stresses of the ring due to its mechanical situation and rotation, aids in the study of asymmetries or defects in motor rings, and measures rotational hysteresis.

Cole, M.

1967-01-01

167

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

168

Dynamical aspects of the adsorption hysteresis phenomenon.  

PubMed

Equilibrium and nonequilibrium transport properties of adsorbates in mesoporous Vycor porous glass have been experimentally studied using nuclear magnetic resonance techniques. With the known geometrical characteristics of porous glass and with measured self-diffusivities, transient sorption curves have been quantitatively compared to those predicted within a Fick's law model. This model correctly describes data outside a hysteresis region. In contrast, in the hysteresis region, a two-step mechanism of density relaxation is required to explain the behavior. These two mechanisms are identified as diffusion at early stages and activated density redistribution at later stages of adsorption. The latter mechanism, being intrinsically slow in nature, is anticipated to prevent the system from reaching equilibrium. PMID:17466768

Valiullin, Rustem; Naumov, Sergej; Galvosas, Petrik; Kärger, Jörg; Monson, Peter A

2007-05-01

169

Analytic synthesis of a hysteresis motor  

Microsoft Academic Search

This paper presents the unique synthesis of a motor with a hysteresis torque–speed characteristic. The machine is synthesized from a conventional polyphase squirrel cage induction motor (SCIM) with a high rotor resistance to leakage reactance r2\\/x2 ratio, which is mechanically coupled to a polyphase transfer field (TF) machine but with an inversion of the usual torque–speed characteristic of the latter

Linus U. Anih; Emeka S. Obe; Eugene O. Agbachi

2011-01-01

170

[Mathematical models of hysteresis]. Progress report No. 4, [January 1, 1991--December 31, 1991  

SciTech Connect

The research described in this proposal is currently being supported by the US Department of Energy under the contract ``Mathematical Models of Hysteresis``. Thus, before discussing the proposed research in detail, it is worthwhile to describe and summarize the main results achieved in the course of our work under the above contract. Our ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with ``nonlocal memories``. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. Our research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. Our study has by and large been centered around the following topics: various generalizations and extensions of the classical Preisach model, finding of necessary and sufficient conditions for the representation of actual hysteretic nonlinearities by various Preisach type models, solution of identification problems for these models, numerical implementation and experimental testing of Preisach type models. Although the study of Preisach type models has constituted the main direction of the research, some effort has also been made to establish some interesting connections between these models and such topics as: the critical state model for superconducting hysteresis, the classical Stoner-Wohlfarth model of vector magnetic hysteresis, thermal activation type models for viscosity, magnetostrictive hysteresis and neural networks.

Mayergoyz, I.D.

1991-12-31

171

Parent Effectiveness Training (P.E.T.): Criticisms and Caveats.  

ERIC Educational Resources Information Center

Criticizes Parent Effectiveness Training (P.E.T.) for its emphasis on one-sided techniques in the parent-child relationship and its tendency to reduce complex problems to simplistic formulas. P.E.T.'s central metaphor of parent-as-therapist is identified and found wanting. Issues have applicability to the parent education movement in general.…

Doherty, William J.; Ryder, Robert G.

1980-01-01

172

Quasiparticle tunneling: P(E) theory John M. Martinis1  

E-print Network

Quasiparticle tunneling: P(E) theory John M. Martinis1 1 Department of Physics, University(E) theory. For a large-capacitance qubit, we extend the theory to include the tunneling of quasiparticles the dissipation due to the tunneling of quasiparticles using the environmental P(E) theory[1] to properly account

Martinis, John M.

173

Effects of matching network on the hysteresis during E and H mode transitions in argon inductively coupled plasma  

SciTech Connect

An experimental investigation of the hysteresis during the E (capacitive coupling) and H mode (inductive coupling) transitions at various matching situation in argon inductively coupled plasma is reported. At high pressure, the results show two hysteresis loops involved the plasma density, applied power, and forward power, as well as the electrical parameters in the discharge circuit, when the series capacitance is cycled. The measured electron density versus applied power shows that the hysteresis loop shrinks with the decrease of the matching capacitance, and the same trend is discovered on the input current, voltage, and phase angle. In addition, for the case of small capacitance, the current (or voltage) jumps to a low value when the discharge passes through the E to H mode transition regime. Contrarily, for the case of large capacitance, the current jumps to a high value while the voltage is almost constant. The evolution characteristics of the plasma and circuit parameters observed imply that the nonlinear behavior of the matching situation may be one of the determined factors for hysteresis.

Gao Fei; Zhao Shuxia; Li Xiaosong; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2010-10-15

174

Low-hysteresis materials for magnetic refrigeration: Gd/sub 1-x/Er/sub x/Al/sub 2/  

SciTech Connect

The series of ferromagnetic intermetallics Gd/sub 1-x/Er/sub x/Al/sub 2/ are candidate working materials for magnetic refrigeration because of their large moment, small anisotropy, and the fact that their Curie temperatures span the range 14 K to 164 K. We have measured the magnitude of the magnetic hysteresis as a function of temperature from 4 K to T/sub c/ for polycrystalline samples of these materials via ac magnetic susceptibility and magnetization hysteresis loops. We found, as expected, virtually no hysteresis in GdAl/sub 2/, and more surprisingly, less than 3000 A/m hysteresis in ErAl/sub 2/, and 2 x 10/sup 4/ A/m in Gd/sub 0/ /sub 5/Er/sub 0/ /sub 5/Al/sub 2/. Moreover, the hysteresis in Gd/sub 0/ /sub 5/Er/sub 0/ /sub 5/Al/sub 2/ was less than or equal to 100 A/m for T - T/sub c/ < 20 K.

Zimm, C.B.; Barclay, J.A.; Johanson, W.R.

1983-01-01

175

Low hysteresis materials for magnetic refrigeration: Gd/sub 1-x/Er/sub x/Al/sub 2/  

SciTech Connect

The series of ferromagnetic intermetallics Gd/sub 1-x/ Er/sub x/Al/sub 2/ are candidate working materials for magnetic refrigeration because of their large moment, small anisotropy, and their wide range of Curie temperatures (14 to 164 K). We have measured the magnitude of the magnetic hysteresis as a function of temperature from 4 K to T/sub C/ for polycrystalline samples of these materials by ac magnetic susceptibility and magnetization hysteresis loops. We found, as expected, virtually no hysteresis in GdAl/sub 2/, and, more surprisingly, less than 3000 A/m hysteresis in ErAl/sub 2/ and 2 x 10/sup 4/ A/m in Gd/sub 0.5/ Er/sub 0.5/Al/sub 2/. Moreover, the hysteresis in Gd/sub 0.5/ Er/sub 0.5/Al/sub 2/ was <100 A/m for T-T/sub C/< 20 K.

Zimm, C.B.; Barclay, J.A.; Johanson, W.R.

1984-03-20

176

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

177

Phasing Loops  

E-print Network

This work consists of a set of eight vector graphics animations exploring phasing loops, intended to be displayed on televisions and monitors, for home use or exhibition in art galleries as Generative Cinema installations. By combining animated...

Guinski, Rodrigo 1980-

2012-11-30

178

NATURE BIOTECHNOLOGY VOLUME 30 NUMBER 6 JUNE 2012 513 P E R S P E C T I V E  

E-print Network

NATURE BIOTECHNOLOGY VOLUME 30 NUMBER 6 JUNE 2012 513 P E R S P E C T I V E Metagenomics holds in comparability of data will facilitate the study of biotechnologically relevant processes, such as bioprospecting, to date, played only a small role in biotechnological research, with the majority of novel developments

Fierer, Noah

179

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

180

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

181

Numerical modelling in the time domain of dynamic hysteresis of soft materials in cylindrical coordinates  

NASA Astrophysics Data System (ADS)

This paper deals with the numerical analysis of soft magnetic materials with hysteresis in dynamic axial symmetric problems. We present a procedure based on a 1D Finite Difference Time Domain (FDTD) algorithm where there are implemented magnetization dependent Preisach based models. Experimental measurements of the virgin curve and the major loop are used to identify the models. The numerical scheme in the time domain proposed is discussed and a probe of its intrinsic stability is given. Numerical codes based on the above algorithm are used to show some of the possibilities of this numerical tool for the dynamic magnetic analysis.

Cardelli, Ermanno; Torre, Edward Della; Pinzaglia, Enrico

2003-05-01

182

Stability of dithered non-linear systems with backlash or hysteresis  

NASA Technical Reports Server (NTRS)

A study is conducted of the effect of dither on the nonlinear element of a single-input single-outout feedback system. Nonlinearities are considered with memory (backlash, hysteresis), in the feedforward loop; a dither of a given amplitude is injected at the input of the nonlinearity. The nonlinearity is followed by a linear element with low-pass characteristic. The stability of the dithered system and an approximate equivalent system (in which the nonlinearity is a smooth function) are compared. Conditions on the input and on the dither frequency are obtained so that the approximate-system stability guarantees that of the given hysteretic system.

Desoer, C. A.; Shahruz, S. M.

1986-01-01

183

Mechano-electric optoisolator transducer with hysteresis  

NASA Astrophysics Data System (ADS)

This article presents a theoretical and experimental study of designing a mechano-electric optoisolator transducer with hysteresis. Our research is centred upon designing transducers on the basis of optical sensors, as photoelectric conversions eliminate the influence of electromagnetic disturbances. Conversion of the rotation/translation motions into electric signals is performed with the help of a LED-photoresistor Polaroid optocoupler. The driver of the optocoupler's transmitter module is an independent current source. The signal conditioning circuit is a Schmitt trigger circuit. The device is designed to be applied in the field of automation and mechatronics.

Ciuru?, I. M.; Dimian, M.; Graur, A.

2011-01-01

184

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

185

Adsorption kinetics in the solution of a thermal hysteresis protein  

NASA Astrophysics Data System (ADS)

According to the properties of the interactions between the thermal hysteresis proteins (THPs) and an ice crystal surface in the THP solution, we present a kinetic theory of the adsorption of thermal hysteresis proteins on the ice crystal surface. The thermal hysteresis activities of the THP solutions are given. The cooperative properties in the adsorption process of the THPs on the ice crystal surface are discussed.

Li, Qianzhong; Luo, Liaofu

2000-04-01

186

Dynamic hysteresis in a one-dimensional Ising model: application to allosteric proteins.  

PubMed

We solve exactly the problem of dynamic hysteresis for a finite one-dimensional Ising model at low temperature. We find that the area of the hysteresis loop, as the field is varied periodically, scales as the square root of the field frequency for a large range of frequencies. Below a critical frequency there is a correction to the scaling law, resulting in a linear relationship between hysteresis area and frequency. The one-dimensional Ising model provides a simplified description of switchlike behavior in allosteric proteins, such as hemoglobin. Thus our analysis predicts the switching dynamics of allosteric proteins when they are exposed to a ligand concentration which changes with time. Many allosteric proteins bind a regulator that is maintained at a nonequilibrium concentration by active signal transduction processes. In the light of our analysis, we discuss to what extent allosteric proteins can respond to changes in regulator concentration caused by an upstream signaling event, while remaining insensitive to the intrinsic nonequilibrium fluctuations in regulator level which occur in the absence of a signal. PMID:16089781

Graham, I; Duke, T A J

2005-06-01

187

Memory characteristics of hysteresis and creep in multi-layer piezoelectric actuators: An experimental analysis  

NASA Astrophysics Data System (ADS)

In this paper we provide an experimental characterization of creep and hysteresis in a multi-layer piezoelectric actuator (PEA), taking into account their relationships in terms of memory structure. We fit the well-known log-t model to the response of the PEA when driven by piecewise-constant signals, and find that both the instantaneous and the delayed response of the PEA display hysteretic dependence on the voltage level. We investigate experimentally the dependence of the creep coefficient on the input history, by driving the PEA along first-order reversal curves and congruent minor loops, and find that it displays peculiar features like strict congruence of the minor loops and discontinuities. We finally explain the observed experimental behaviors in terms of a slow relaxation of the staircase interface line in the Preisach plane.

Biggio, Matteo; Butcher, Mark; Giustiniani, Alessandro; Masi, Alessandro; Storace, Marco

2014-02-01

188

Effect of Air gap variation on characteristics of an Axial flux hysteresis motor  

Microsoft Academic Search

Axial flux hysteresis motor (AFHM) such as other types of hysteresis motor is self-starting synchronous motor that use the hysteresis characteristics of magnetic materials. It is known that the magnetic characteristics of hysteresis motor could be easily affected by air gap and structure dimensions variation. Air gap length plays an important role in flux distribution in hysteresis ring that can

Mohammad Modarres; Abolfazl Vahedi; Mohammadreza Ghazanchaei

2010-01-01

189

Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume.  

PubMed

The growth and reduction of Northern Hemisphere ice sheets over the past million years is dominated by an approximately 100,000-year periodicity and a sawtooth pattern (gradual growth and fast termination). Milankovitch theory proposes that summer insolation at high northern latitudes drives the glacial cycles, and statistical tests have demonstrated that the glacial cycles are indeed linked to eccentricity, obliquity and precession cycles. Yet insolation alone cannot explain the strong 100,000-year cycle, suggesting that internal climatic feedbacks may also be at work. Earlier conceptual models, for example, showed that glacial terminations are associated with the build-up of Northern Hemisphere 'excess ice', but the physical mechanisms underpinning the 100,000-year cycle remain unclear. Here we show, using comprehensive climate and ice-sheet models, that insolation and internal feedbacks between the climate, the ice sheets and the lithosphere-asthenosphere system explain the 100,000-year periodicity. The responses of equilibrium states of ice sheets to summer insolation show hysteresis, with the shape and position of the hysteresis loop playing a key part in determining the periodicities of glacial cycles. The hysteresis loop of the North American ice sheet is such that after inception of the ice sheet, its mass balance remains mostly positive through several precession cycles, whose amplitudes decrease towards an eccentricity minimum. The larger the ice sheet grows and extends towards lower latitudes, the smaller is the insolation required to make the mass balance negative. Therefore, once a large ice sheet is established, a moderate increase in insolation is sufficient to trigger a negative mass balance, leading to an almost complete retreat of the ice sheet within several thousand years. This fast retreat is governed mainly by rapid ablation due to the lowered surface elevation resulting from delayed isostatic rebound, which is the lithosphere-asthenosphere response. Carbon dioxide is involved, but is not determinative, in the evolution of the 100,000-year glacial cycles. PMID:23925242

Abe-Ouchi, Ayako; Saito, Fuyuki; Kawamura, Kenji; Raymo, Maureen E; Okuno, Jun'ichi; Takahashi, Kunio; Blatter, Heinz

2013-08-01

190

Efficient parameter estimation techniques for hysteresis models  

NASA Astrophysics Data System (ADS)

Actuators employing ferroelectric or ferromagnetic compounds are solid-state, efficient, and compact making them well-suited for aerospace, aeronautic, industrial and military applications. However, they also exhibit frequency, stress and thermally-dependent hysteresis and constitutive nonlinearities which must be incorporated in models for accurate device characterization and control design. A critical step in the use of these models is the estimation or re-estimation of parameters in a manner that is both efficient and robust. In this presentation, we discuss techniques to estimate densities in the homogenized energy model based on Galerkin expansions using physically motivated basis functions. The yields highly tractable optimization algorithms in which initial parameter estimates can be obtained from measured properties of the data. The efficiency and accuracy of the models and estimation algorithms are validated with experimental data.

Ernstberger, J. M.; Smith, R. C.

2009-03-01

191

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

192

Application of the Preisach model in soil-moisture hysteresis  

E-print Network

Application of the Preisach model in soil-moisture hysteresis Denis Flynn, Hugh McNamara, Philip O- teresis effects in the relation between water retention and soil-moisture ten- sion. Special, one parameter, classes of Preisach operators are proposed to construct models of the soil-moisture hysteresis

Schellekens, Michel P.

193

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 friction between two surfaces in adhesive contact with the loading­unloading adhesion hysteresis between them. We then examine in light of this model the observed low friction between two mica surfaces coated

Klein, Jacob

194

A Temperature-Dependent Hysteresis Model for Relaxor Ferroelectric Compounds  

E-print Network

subsequently incorporated the hysteretic low-temperature behavior through the development of domain wall modelsA Temperature-Dependent Hysteresis Model for Relaxor Ferroelectric Compounds Julie K. Raye- ature-dependent hysteresis and constitutive nonlinearities inherent to relaxor ferroelectric materials

195

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith  

E-print Network

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith Center for Research in Scienti c and control design, we consider a theory for ferroelectric hysteresis which is based on domain wall dynamics been recognized that domain and domain wall mechanisms within ferroelectric materi- als result

196

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith  

E-print Network

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith Center for Research in Scientific and control design, we consider a theory for ferroelectric hysteresis which is based on domain wall dynamics been recognized that domain and domain wall mechanisms within ferroelectric materi­ als result

197

Analysis and Determination of Ring Flux Distribution in Hysteresis Motors  

Microsoft Academic Search

This paper presents the results of an experimental determination of the flux distributions inside different layers of the hysteresis ring. The flux measurements were made by means of search coils embedded in the stationary ring of an inside-out three phase hysteresis motor. It is found that the flux distribution is quite nonuniform and there exist phase shift between the flux

R. D. Jackson; M. A. Rahman; G. R. Slemon

1983-01-01

198

Sensitivity analysis to the design parameters of a hysteresis motor  

Microsoft Academic Search

Hysteresis motors are mainly used for some applications that need very smooth torque from starting to synchronous speed such as gyroscope and gas centrifuge. This paper presents a sensitivity analysis of 60 W, 400 V, 6000 rpm super-high speed hysteresis motor characteristics including electromagnetic torque, power factor, efficiency and stator current to the design parameters including mechanical, electrical and magnetic

Abolfazl Halvaei Niasar; Hassan Moghbelli

2012-01-01

199

Magnetic equivalent circuit of PM hysteresis synchronous motor  

Microsoft Academic Search

This paper presents the magnetic equivalent circuit of a permanent magnet hysteresis synchronous motor (PMHS). The hybrid synchronous motor consists of 36% cobalt steel hysteresis alloys with neodymium iron boron permanent magnets to improve the overall performances of such a motor. Based on the magnetic equivalent circuit, the control strategy of the PMHS motor is developed. Experimental results confirm the

R. Qin; M. A. Rahman

2003-01-01

200

A permanent magnet hysteresis hybrid synchronous motor for electric vehicles  

Microsoft Academic Search

This paper presents the design, analysis and PWM vector control of a hybrid permanent magnet hysteresis synchronous (PMHS) motor with a view to improve the performances of motors for electric vehicle applications. This hybrid design combines the advantageous performance features of both conventional hysteresis motors and permanent magnet motors. Electrical equivalent circuits of the PMHS motor are developed for both

M. Azizur Rahman; Ruifeng Qin

1997-01-01

201

Starting and synchronization of permanent magnet hysteresis motors  

Microsoft Academic Search

This paper presents the design and application of permanent magnets in hysteresis motors with a view to improve the overall performances of such motors. The novel rotor consists of 36% cobalt steel alloys with neodymium boron iron permanent magnets. This hybrid design combines advantageous performance features of both typical permanent magnet motors and conventional hysteresis motors. Machine models for steady

M. A. Rahman; Ruifeng Qin

1994-01-01

202

Design of a compact hysteresis motor used in a gyroscope  

Microsoft Academic Search

In this paper, it presents the computer-aided design and test results of a compact hysteresis synchronous motor used as the drive motor of a gyroscope. Hysteresis motor is the best choice for this application because of its compactness and reliability. Also it has self-starting capability and it does not require any position sensor and communication circuits.

Rajagopal KR

2003-01-01

203

Starting and synchronization of permanent magnet hysteresis motors  

Microsoft Academic Search

This paper presents the design, analysis, and application of permanent magnets in a hysteresis motor with a view to improve the overall performance of such motors. The novel rotor consists of 36% cobalt steel alloys with neodymium boron iron permanent magnets. This hybrid design combines the advantageous performance features of both typical permanent magnet motors and conventional hysteresis motors. The

M. Azizur Rahman; Ruifeng Qin

1996-01-01

204

Magnetic equivalent circuit of PM hysteresis synchronous motor  

Microsoft Academic Search

This paper presents the magnetic equivalent circuit of a permanent magnet hysteresis synchronous (PMHS) motor. The hybrid synchronous motor consists of 30% Cobalt-steel hysteresis alloys Neodymium Iron Boron (NdFeB) permanent magnets to improve the overall performances of motors.

Ruifeng Qin; M. A. Rahman

2003-01-01

205

Analysis and Determination of Ring Flux Distribution in Hysteresis Motors  

Microsoft Academic Search

This paper presents the results of an experimental determination of the flux distributions inside different layers of the hysteresis ring. The flux measurements were made by means of search coils embedded in the stationary ring of an inside-out three phase hysteresis motor. It is found that the flux distribution is quite non-uniform and there exist phase shift between the flux

R. D. Jackson; M. A. Rahman; G. R. Slemon

1983-01-01

206

A permanent magnet hysteresis hybrid motor drive for electric vehicles  

Microsoft Academic Search

This paper presents the design, analysis and PWM vector control of a hybrid permanent magnet hysteresis synchronous motor with a view to improve the performances of the motors for electric vehicle application. This hybrid design combines the advantageous performance features of both the conventional hysteresis motors and the permanent magnet motors. A PWM vector control simulation and experimental results for

M. A. Rahman; Ruifeng Qin

1996-01-01

207

Performance simulation of hysteresis motors using accurate rotor media models  

Microsoft Academic Search

Recently, there has been an increased demand for small and medium sized brushless-type synchronous motors. Among these types, hysteresis motors have been especially used in those applications requiring precise speed and constant starting torque capabilities. In the past, several digital techniques for simulating the performance of hysteresis motors have been developed. These technique, however, involved significant approximations to the rotor

Amr A. Adly

1995-01-01

208

Impact of relative permeability hysteresis on geological CO2 storage  

Microsoft Academic Search

Relative permeabilities are the key descriptors in classical formulations of multiphase flow in porous media. Experimental evidence and an analysis of pore-scale physics demonstrate conclusively that relative permeabilities are not single functions of fluid saturations and that they display strong hysteresis effects. In this paper, we evaluate the relevance of relative permeability hysteresis when modeling geological CO2 sequestration processes. Here

R. Juanes; E. J. Spiteri; F. M. Orr Jr; M. J. Blunt

2006-01-01

209

Bistability and Hysteresis in the Organization of Apparent Motion Patterns  

Microsoft Academic Search

In a paradigm for which 2 distinct patterns are perceived for the same stimulus, perceptual hysteresis (persistence of a percept despite parameter change to values favoring the alternative pattern) and temporal stability (persistence despite intrinsic propensities toward spontaneous change) are interdependent. Greater persistence during parameter change reduces temporal stability, slowing the rate of parameter change reduces hysteresis by increasing opportunity

Howard S. Hock; J. A. Scott Kelso; Gregor Schöner

1993-01-01

210

The Effect of Liquid Structure on Contact Angle Hysteresis.  

National Technical Information Service (NTIS)

Contact angle hysteresis was measured for a variety of liquids on condensed monolayers of 17-(perfluoroheptyl)-heptadecanoic acid adsorbed on polished chromium. The hysteresis was shown to be simply related to the molecular volume of the liquid and to res...

C. O. Timmons, W. A. Zisman

1966-01-01

211

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

2014-02-11

212

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

213

Numerical determination of hysteresis parameters for the modeling of magnetic properties using the theory of ferromagnetic hysteresis  

Microsoft Academic Search

The authors describe how the various model parameters needed to describe hysteresis on the basis of the Jiles-Atherton theory can be calculated from experimental measurements of the coercivity, remanence, saturation magnetization, initial anhysteretic susceptibility, initial normal susceptibility, and maximum differential susceptibility. The determination of hysteresis parameters based on this limited set of magnetic properties is of the most practical use

D. C. Jiles; J. B. Thoelke; M. K. Devine

1992-01-01

214

Quantification of Hysteresis and Nonlinear Effects on the Frequency Response of Ferroelectric and  

E-print Network

Quantification of Hysteresis and Nonlinear Effects on the Frequency Response of Ferroelectric. However, these materials also exhibit hysteresis and constitutive nonlinearities at all drive levels of hysteresis and nonlinearities on the frequency behavior of devices that employ these compounds. Whereas

215

Control of Hysteresis in Smart Actuators. Part 1. Modeling, Parameter Identification, and Inverse Control.  

National Technical Information Service (NTIS)

Hysteresis in smart actuators presents a challenge in control of these actuators. A fundamental idea to cope with hysteresis is inverse compensation. In this paper we study modeling, identification and inverse control of hysteresis in smart actuators thro...

X. Tan, J. S. Baras

2002-01-01

216

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

217

Jorge A. Arroyo, P.E. Texas Water Development Board  

E-print Network

conservation and water-related research Water resource data collection and research #12;#12;Water ScienceJorge A. Arroyo, P.E. Texas Water Development Board Presenting to Center for Integrated Earth System Science Austin, Texas February 13, 2012 Texas Water Development Board Innovative Water

Yang, Zong-Liang

218

High contact angle hysteresis of superhydrophobic surfaces: Hydrophobic defects  

NASA Astrophysics Data System (ADS)

A typical superhydrophobic surface is essentially nonadhesive and exhibits very low water contact angle (CA) hysteresis, so-called Lotus effect. However, leaves of some plants such as scallion and garlic with an advancing angle exceeding 150° show very serious CA hysteresis. Although surface roughness and epicuticular wax can explain the very high advancing CA, our analysis indicates that the unusual hydrophobic defect, diallyl disulfide, is the key element responsible for contact line pinning on allium leaves. After smearing diallyl disulfide on an extended polytetrafluoroethylene (PTFE) film, which is originally absent of CA hysteresis, the surface remains superhydrophobic but becomes highly adhesive.

Chang, Feng-Ming; Hong, Siang-Jie; Sheng, Yu-Jane; Tsao, Heng-Kwong

2009-08-01

219

Static measurements of slender delta wing rolling moment hysteresis  

NASA Technical Reports Server (NTRS)

Slender delta wing planforms are susceptible to self-induced roll oscillations due to aerodynamic hysteresis during the limit cycle roll oscillation. Test results are presented which clearly establish that the static rolling moment hysteresis has a damping character; hysteresis tends to be greater when, due to either wing roll or side slip, the vortex burst moves back and forth over the wing trailing edge. These data are an indirect indication of the damping role of the vortex burst during limit cycle roll oscillations.

Katz, Joseph; Levin, Daniel

1991-01-01

220

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

221

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

222

Hysteresis as a Marker for Complex, Overlapping Landscapes in Proteins  

PubMed Central

Topologically complex proteins fold by multiple routes as a result of hard-to-fold regions of the proteins. Oftentimes these regions are introduced into the protein scaffold for function and increase frustration in the otherwise smooth-funneled landscape. Interestingly, while functional regions add complexity to folding landscapes, they may also contribute to a unique behavior referred to as hysteresis. While hysteresis is predicted to be rare, it is observed in various proteins, including proteins containing a unique peptide cyclization to form a fluorescent chromophore as well as proteins containing a knotted topology in their native fold. Here, hysteresis is demonstrated to be a consequence of the decoupling of unfolding events from the isomerization or hula-twist of a chromophore in one protein and the untying of the knot in a second protein system. The question now is- can hysteresis be a marker for the interplay of landscapes where complex folding and functional regions overlap? PMID:23525263

Andrews, Benjamin T.; Capraro, Dominique T.; Sulkowska, Joanna I.; Onuchic, Jose N.; Jennings, Patricia A.

2013-01-01

223

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.

224

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.

225

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

226

Hysteresis characterization using charge feedback control for a LIPCA device  

NASA Astrophysics Data System (ADS)

In this paper, we study the no-load behavior of a lightweight piezo-composite curved actuator (LIPCA) subjected to voltage and charge control. First, we examine the effect of hysteresis and creep when the actuator is voltage controlled at a slow scan speed. The experimental results show that creep increases the displacement hysteresis by over 25% when scanning at 1/60 Hz. Afterwards, we discuss the design and implementation of a charge-feedback circuit to control the displacement of the actuator. The hysteresis curves between voltage- and charge-control modes are compared for the scan frequencies of 1 and 5 Hz. The results show that charge control (compared to voltage control) of a LIPCA device exhibits significantly less hysteresis, over 80% less.

Beck, James; Noras, Maciej; Kieres, Jerzy; Speich, John E.; Mossi, Karla M.; Leang, Kam K.

2006-03-01

227

Low-Hysteresis Flow-Through Wind-Tunnel Balance  

NASA Technical Reports Server (NTRS)

Improved flow-through wind-tunnel balance includes features minimizing both spurious force readings caused by internal pressurized flow and mechanical hysteresis. Symmetrical forces caused by internal flow cancelled.

Kunz, N.; Luna, P. M.; Roberts, A. C.; Smith, R. C.; Horne, W. L.; Smith, K. M.

1992-01-01

228

Hysteresis in Thin-Film Rechargeable Lithium Batteries  

SciTech Connect

Discharge - charge cycling of thin-film rechargeable lithium batteries with an amorphous or nanocrystalline LiXMn2.Y04 cathode reveals evidence for a true hysteresis in the lithium insertion reaction. This is compared with an apparent hysteresis attributed to a kinetically hindered phase transition near 3 V for batteries with either a crystalline or a nanocrystalline LiJ@Yo4 cathode.

Bates, J.B.; Dudney, N.J.; Evans, C.D.; Hart, F.X.

1999-04-25

229

Design of a compact hysteresis motor used in a gyroscope  

Microsoft Academic Search

This paper presents the computer-aided design and test results of a compact three-phase hysteresis synchronous motor used as the drive motor of a gyroscope. Hysteresis motor is the best choice for this application because of its compactness and reliability. Also, it has a self-starting capability and it does not require any position sensor and commutation circuits. The design of a

K. R. Rajagopal

2003-01-01

230

Transient performance analysis for permanent-magnet hysteresis synchronous motor  

Microsoft Academic Search

The combination of hysteresis and permanent-magnet materials in the rotor of a self-starting synchronous motor makes the motor analysis very difficult due to its inherent nonlinearity. This paper presents the simulation results of the transient performance of permanent magnet hysteresis synchronous (PMHS) motors. The major feature in this study is to combine the time-stepping finite-element technique with the model for

Kazumi Kurihara; M. Azizur Rahman

2004-01-01

231

Stabilization of supercooled fluids by thermal hysteresis proteins.  

PubMed Central

It has been reported that thermal hysteresis proteins found in many cold-hardy, freeze-avoiding arthropods stabilize their supercooled body fluids. We give evidence that fish antifreeze proteins, which also produce thermal hysteresis, bind to and reduce the efficiency of heterogenous nucleation sites, rather than binding to embryonic ice nuclei. We discuss both possible mechanisms for stabilization of supercooled body fluids and also describe a new method for measuring and defining the supercooling point of small volumes of liquid. PMID:7612853

Wilson, P W; Leader, J P

1995-01-01

232

Hysteresis as an implicit prior in tactile spatial decision making.  

PubMed

Perceptual decisions not only depend on the incoming information from sensory systems but constitute a combination of current sensory evidence and internally accumulated information from past encounters. Although recent evidence emphasizes the fundamental role of prior knowledge for perceptual decision making, only few studies have quantified the relevance of such priors on perceptual decisions and examined their interplay with other decision-relevant factors, such as the stimulus properties. In the present study we asked whether hysteresis, describing the stability of a percept despite a change in stimulus property and known to occur at perceptual thresholds, also acts as a form of an implicit prior in tactile spatial decision making, supporting the stability of a decision across successively presented random stimuli (i.e., decision hysteresis). We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide 'same' rather than 'different' on successively presented pin distances. In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants' decisions than hysteresis. However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance. Furthermore, the less variance was explained by the pin distance on a given decision, the more variance was explained by hysteresis, and vice versa. Our findings suggest that hysteresis acts as an implicit prior in tactile spatial decision making that becomes increasingly important when explicit stimulus properties provide decreasing evidence. PMID:24587045

Thiel, Sabrina D; Bitzer, Sebastian; Nierhaus, Till; Kalberlah, Christian; Preusser, Sven; Neumann, Jane; Nikulin, Vadim V; van der Meer, Elke; Villringer, Arno; Pleger, Burkhard

2014-01-01

233

Hysteresis as an Implicit Prior in Tactile Spatial Decision Making  

PubMed Central

Perceptual decisions not only depend on the incoming information from sensory systems but constitute a combination of current sensory evidence and internally accumulated information from past encounters. Although recent evidence emphasizes the fundamental role of prior knowledge for perceptual decision making, only few studies have quantified the relevance of such priors on perceptual decisions and examined their interplay with other decision-relevant factors, such as the stimulus properties. In the present study we asked whether hysteresis, describing the stability of a percept despite a change in stimulus property and known to occur at perceptual thresholds, also acts as a form of an implicit prior in tactile spatial decision making, supporting the stability of a decision across successively presented random stimuli (i.e., decision hysteresis). We applied a variant of the classical 2-point discrimination task and found that hysteresis influenced perceptual decision making: Participants were more likely to decide ‘same’ rather than ‘different’ on successively presented pin distances. In a direct comparison between the influence of applied pin distances (explicit stimulus property) and hysteresis, we found that on average, stimulus property explained significantly more variance of participants’ decisions than hysteresis. However, when focusing on pin distances at threshold, we found a trend for hysteresis to explain more variance. Furthermore, the less variance was explained by the pin distance on a given decision, the more variance was explained by hysteresis, and vice versa. Our findings suggest that hysteresis acts as an implicit prior in tactile spatial decision making that becomes increasingly important when explicit stimulus properties provide decreasing evidence. PMID:24587045

Thiel, Sabrina D.; Bitzer, Sebastian; Nierhaus, Till; Kalberlah, Christian; Preusser, Sven; Neumann, Jane; Nikulin, Vadim V.; van der Meer, Elke; Villringer, Arno; Pleger, Burkhard

2014-01-01

234

Aileron roll hysteresis effects on entry of space shuttle orbiter  

NASA Technical Reports Server (NTRS)

Six-degree-of-freedom simulations of the space shuttle orbiter entry with control hysteresis were conducted on the NASA Langley Research Center interactive simulator known as the automatic reentry flight dynamics simulator. These simulations revealed that the vehicle can tolerate control hysteresis producing a + or - 50 percent change in the nominal aileron roll characteristics and an offset in the nominal characteristics equivalent to a + or - 5 deg aileron deflection with little increase in the reaction control system's fuel consumption.

Powell, R. W.

1977-01-01

235

The significance of observed rotational magnetic hysteresis in lunar samples  

NASA Technical Reports Server (NTRS)

Rotational magnetic hysteresis curves for lunar soils 10084, 12070, and 14259, and rock 14053 have been published. There is no adequate explanation to date for the observed large hysteresis at high fields. Lunar rock magnetism researchers consider fine particle iron to be the primary source of stable magnetic remanence in lunar samples. Iron has cubic anisotropy with added shape anisotropy for extreme particle shapes. The observed high-field hysteresis must have its source in uniaxial or unidirectional anisotropy. This implies the existence of minerals with uniaxial anisotropy or exchange-coupled spin states. Therefore, the source of this observed high-field hysteresis must be identified and understood before serious paleointensity studies are made. It is probable that the exchange-coupled spin states and/or the source of uniaxial anisotropy responsible for the high-field hysteresis might be influenced by the lunar surface diurnal temperature cycling. The possible sources of high-field hysteresis in lunar samples are presented and considered.

Wasilewski, P.

1974-01-01

236

Torque computation of hysteresis motor using finite element analysis with asymmetric two dimensional magnetic permeability tensor  

Microsoft Academic Search

This paper deals with the analysis of the generated torque of the hysteresis motor using finite element method, The material property of the hysteresis ring in the hysteresis motor is characterized by the asymmetric two dimensional magnetic permeability tensor. The torque has been computed effectively by using permeability tensor instead of full hysteresis modeling or Maxwell stress tensor. The proposed

Hak-Yong Lee; Song-Yop Hahn; Gwan-Soo Park; Ki-Sik Lee

1998-01-01

237

Optimization of a new type of hysteresis motor using genetic algorithm  

Microsoft Academic Search

HYSTERESIS motors are self-starting synchronous motors that take advantage of the hysteresis characteristics of the magnetic materials. Robust structure, flat speed-torque characteristics, smooth operation and constant low starting current are the outstanding specifications of these machines. Nevertheless, low efficiency and low power factor are among the disadvantages of common hysteresis motors. Very recently, Coreless Dual Discs Hysteresis Motor (CDDHM) has

M. H. Sadeghi; A. Darabi

2010-01-01

238

Ferromagnetism, hysteresis and enhanced heat dissipation in assemblies of superparamagnetic nanoparticles  

NASA Astrophysics Data System (ADS)

In this paper, we develop theoretical frameworks to explain the emergence of ferromagnetism in suspensions and agglomerates of superparamagnetic (SPM) nanoparticles. In the limit of strong anisotropy, the super moments can be treated as a collection of two-state Ising spins. When adequate in number, they interact via dipole-dipole coupling to produce a dipolar field and subsequently a permanent dipole moment. As a result, this effectual ferromagnet exhibits hysteresis on the application of an oscillating magnetic field yielding heat dissipation that is several orders of magnitude larger than in a paramagnet. Using our frameworks, we provide a design for a magnetite-blood suspension that yields heat dissipation in the mW range. Its important physical application is in remedial procedures for destroying tumor and cancer cells. We are also able to explain many experiments reporting manifestations of ferromagnetism in the form of hysteresis loops, return point memory and large heat dissipation in suspensions and aggregates of SPM nanoparticles. Our frameworks can be used to manipulate heat dissipation in variety of combinations of particles and their embedding mediums. They impart a basis to the often used ad-hoc methodologies in this subject.

Singh, Vanchna; Banerjee, Varsha

2012-12-01

239

396 | MAY 2004 | VOLUME 5 www.nature.com/reviews/genetics P E R S P E C T I V E S  

E-print Network

396 | MAY 2004 | VOLUME 5 www.nature.com/reviews/genetics P E R S P E C T I V E S Micromanagers (siRNAs) of RNAi in sev- eral respects: miRNAs are generally conserved #12;P E R S P E C T I V ERNA gene families in both plant and animal lineages20,35,36 ,indicates that de novo emergence of new mi

Bartel, David

240

Intelligent compensation of friction, ripple, and hysteresis via a regulated chatter.  

PubMed

In this paper, a hybrid control scheme utilizing a PID feedback control with an additional regulated chatter signal is developed to compensate motion impeding influences such as the effects due to friction, force ripples, and hysteresis in linear piezoelectric motor. The regulated chatter signal is a pulse sequence superimposed on the PID control signal. It has a fixed amplitude, and a pulse width regulated via iterative learning control. As such, the scheme is expected to be useful for applications involving iterative motion sequences. An analysis of the closed-loop performance is presented in the paper. Simulation and experimental results are also furnished to demonstrate that the proposed control scheme can reduce tracking errors significantly. PMID:16856637

Zhao, S; Putra, A S; Tan, K K; Panda, S K; Lee, T H

2006-07-01

241

Diagonal Mesh Equivalent (DME) for the calculation of the hysteresis losses in electrical machines  

NASA Astrophysics Data System (ADS)

The Magnetic Equivalent Circuits (MECs) technique is a powerful tool for machine analysis and power losses computation. Here, use is made of the Diagonal Mesh Equivalent (DME) to solve the equivalent electrical circuit for the branch fluxes to be easily computed and related to the machine compartments of technical interest. These are represented by the air gap, stator and rotor to name a few. Hysteresis loops have been computed, along with the static power losses, for assigned stator thicknesses and compared to ones alternatively obtained by the Modified Scalar Preisach Model. This study is especially aimed at giving improved issues to those who are engaged in the design of magnetic components for electrical machines.

Vergura, S.; Carpentieri, M.; Lattarulo, F.

2014-02-01

242

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

243

Large Thermal Hysteresis for Iron(II) Spin Crossover Complexes with N-(Pyrid-4-yl)isonicotinamide.  

PubMed

A new series of iron(II) 1D coordination polymers with the general formula [FeL1(pina)]·xsolvent with L1 being a tetradentate N2O2(2-) coordinating Schiff-base-like ligand [([3,3']-[1,2-phenylenebis(iminomethylidyne)]bis(2,4-pentanedionato)(2-)-N,N',O(2),O(2)'], and pina being a bridging axial ligand N-(pyrid-4-yl)isonicotinamide, are discussed. The X-ray crystal structure of [FeL1(pina)]·2MeOH was solved for the low-spin state. The compound crystallizes in the monoclinic space group P21/c, and the analysis of the crystal packing reveals the formation of a hydrogen bond network where additional methanol molecules are included. Different magnetic properties are observed for the seven samples analyzed, depending on the nature of the included solvent molecules. The widest hysteresis loop is observed for a fine crystalline sample of composition [FeL1(pina)]·xH2O/MeOH. The 88 K wide thermal hysteresis loop (T1/2? = 328 K and T1/2? = 240 K) is centered around room temperature and can be repeated without of a loss of the spin transition properties. For the single crystals of [FeL1(pina)]·2MeOH, a 51 K wide hysteresis loop is observed (T1/2? = 296 K and T1/2? = 245 K) that is also stable for several cycles. For a powder sample of [FeL1(pina)]·0.5H2O·0.5MeOH a cooperative spin transition with a 46 K wide hysteresis loop around room temperature is observed (T1/2? = 321 K and T1/2? = 275 K). This compound was further investigated using Mössbauer spectroscopy and DSC. Both methods reveal that, in the cooling mode, the spin transition is accompanied by a phase transition while in the heating mode a loss of the included methanol is observed that leads to a loss of the spin transition properties. These results show that the pina ligand was used successfully in a crystal-engineering-like approach to generate 1D coordination polymers and improve their spin crossover properties. PMID:25314334

Lochenie, Charles; Bauer, Wolfgang; Railliet, Antoine P; Schlamp, Stephan; Garcia, Yann; Weber, Birgit

2014-11-01

244

Steady-State Performance Analysis of Polyphase Hysteresis-Reluctance Motors  

Microsoft Academic Search

It is well-known that the hysteresis-reluctance motor produces a torque that is a combination of the hysteresis and reluctance effects. Consequently, the performance characteristics of a hysteresis-reluctance motor would be improved when compared to that of the plain hysteresis motor. A new design of a hysteresis-reluctance rotor is presented in which the magnetic saliency is created by cutting slots in

M. Azizur Rahman; Ali M. Osheiba

1985-01-01

245

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

246

Hysteresis loops of individual Co nanostripes measured by magnetic force microscopy  

PubMed Central

High-resolution magnetic imaging is of utmost importance to understand magnetism at the nanoscale. In the present work, we use a magnetic force microscope (MFM) operating under in-plane magnetic field in order to observe with high accuracy the domain configuration changes in Co nanowires as a function of the externally applied magnetic field. The main result is the quantitative evaluation of the coercive field of the individual nanostructures. Such characterization is performed by using an MFM-based technique in which a map of the magnetic signal is obtained as a function of both the lateral displacement and the magnetic field. PMID:21711935

2011-01-01

247

An Approach to Estimate Interface Shear Stress of Ceramic Matrix Composites from Hysteresis Loops  

Microsoft Academic Search

An approach to estimate interface shear stress of ceramic matrix composites during fatigue loading has been developed in this\\u000a paper. By adopting a shear-lag model which includes the matrix shear deformation in the bonded region and friction in the\\u000a debonded region, the matrix crack space and interface debonding length are obtained by matrix statistical cracking model and\\u000a fracture mechanics interface

Longbiao Li; Yingdong Song

2010-01-01

248

Self consistent generalized model for the calculation of minor loop excursions in the theory of hysteresis.  

National Technical Information Service (NTIS)

In the previous work it has been shown that the magnetization curves of a wide range of ferromagnetic materials can be calculated from a simple theory which invokes a constant energy loss per unit change in magnetization. The energy loss, which is therefo...

D. C. Jiles

1992-01-01

249

INSIDE THE HYSTERESIS LOOP: MULTIPLICITY OF INTERNAL STATES IN CONFINED FLUIDS. (R825959)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

250

Simulation of a vector hysteresis measurement system taking hysteresis into account by the vector Preisach model  

NASA Astrophysics Data System (ADS)

The paper deals with the numerical analysis of a rotational single sheet tester with round-shaped specimen (RRSST) which is now under construction. The measurement setup consists of an induction motor the rotor of which has been removed, and its windings have been replaced to a special two phase one which can generate homogeneous magnetic field inside the motor. The two orthogonal components of the magnetic field intensity and of the magnetic flux density vectors can be measured by H-coils and B-coils, respectively. The Finite Element Method (FEM) with the T, ?-? potential formulation has been applied in the simulations. The vector hysteresis property of the specimen has been approximated by the vector Preisach model. Finally, the nonlinear problem has been solved by the fixed-point technique. The aim of the present work is to focus on the design aspects of this kind of measurement system.

Kuczmann, Miklós

2008-02-01

251

A Precise Open-Loop Torque Control for an Interior Permanent Magnet Synchronous Motor  

E-print Network

. Iron losses are mainly caused by hysteresis and eddy currents and therefore depend on the actual motorA Precise Open-Loop Torque Control for an Interior Permanent Magnet Synchronous Motor (IPMSM@lea.upb.de Abstract-Interior permanent magnet synchronous motors (IPMSM) are preferentially chosen as traction drives

Paderborn, Universität

252

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

253

Hysteresis in the production of force by larval Dipteran muscle.  

PubMed

We describe neuromuscular hysteresis - the dependence of muscle force on recent motoneuron activity - in the body wall muscles of larval Sarcophaga bullata and Drosophila melanogaster. In semi-intact preparations, isometric force produced by a train of nerve impulses at a constant rate was significantly less than that produced by the same train of stimuli with a brief (200 ms) high-frequency burst of impulses interspersed. Elevated force did not decay back to predicted values after the burst but instead remained high throughout the duration of the stimulus train. The increased force was not due to a change in excitatory junction potentials (EJPs); EJP voltage and time course before and after the high-frequency burst were not statistically different. Single muscle and semi-intact preparations exhibited hysteresis similarly, suggesting that connective tissues of the origin or insertion are not crucial to the mechanism of hysteresis. Hysteresis was greatest at low motoneuron rates - yielding a approximately 100% increase over predicted values based on constant-rate stimulation alone - and decreased as impulse rate increased. We modulated motoneuron frequency rhythmically across rates and cycle periods similar to those observed during kinematic analysis of larval crawling. Positive force hysteresis was also evident within these more physiological activation parameters. PMID:20581278

Paterson, Bethany A; Anikin, Ilya Marko; Krans, Jacob L

2010-07-15

254

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

255

A Fluid Mechanical Interpretation of Hysteresis in Rhinomanometry  

PubMed Central

A hysteresis effect in the pressure/flow rate relationship of nasal breathing has frequently been observed in clinical tests and in lab investigations. Explanations that have been given in the literature are missing a fluid mechanic storage effect coming into play in reciprocating flows. This effect depends primarily on the way the rhinomanometric measurements are set up and not so much on the nose flow itself. This is to be shown by calculations and experiments. The experiments are carried out with orifices because they can represent nose flow and are often implemented in rhinomanometric equipment as flow gauges. To mimic reality also a 1?:?1 nose model is used. It is shown where the hysteresis comes from and what the key parameters for its prediction are. With these results hysteresis in nasal breathing appears in a new light. PMID:23724249

Gross, T. F.; Peters, F.

2011-01-01

256

The apparent hysteresis in hormone-agonist relationships  

PubMed Central

It has been noted in multiple studies that the calcium–PTH axis, among others, is subject to an apparent hysteresis. We sought to explain a major component of the observed phenomenon by constructing a simple mathematical model of a hormone and secretagogue system with concentration dependent secretion and containing two delays. We constructed profiles of the hormone–agonist axis in this model via four types of protocols, three of which emulating experiments from the literature, and observed a delay- and load-dependent hysteresis that is an expected mathematical artifact of the system described. In particular, the delay associated with correction allows for over-secretion of the hormone influencing the corrective mechanism; thus rate dependence is an artifact of the corrective mechanism, not a sensitivity of the gland to the magnitude of change. From these observations, the detected hysteresis is due to delays inherent in the systems being studied, not in the secretory mechanism. PMID:22154846

Pruett, William A.; Hester, Robert L.; Coleman, Thomas G.

2011-01-01

257

A modified Prandtl-Ishlinskii modeling method for hysteresis  

NASA Astrophysics Data System (ADS)

A modified Prandtl-Ishlinskii modeling method for rate-independent hysteresis in piezoelectric actuators is proposed in this paper. In this method, a generalized backlash operator (GBO) regarded as the elementary operator is introduced into the model so as to be more flexible for modeling of complex hysteresis. Moreover, the Levenberg-Marquardt algorithm is used to estimate the parameters of the model. Thus, all the parameters of the modified PI model can be determined automatically. From this way, it avoids the tedious procedure for the selection of the operator parameters by trial and error. Then, a group of proper Clarke subgradients of the GBO outputs with respect to their parameters at a non-smooth point is obtained based on the bundle method. Finally, the experimental results of applying the proposed method to the modeling of hysteresis in a piezoelectric actuator and an ultrasonic motor (USM) are illustrated, respectively.

Dong, Ruili; Tan, Yonghong

2009-05-01

258

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

259

Contact Hysteresis and Friction of Alkanethiol SAMs on Au  

SciTech Connect

Nanoindentation has been combhed with nanometer-scale friction measurements to identi~ dissipative mechanisms responsible for friction in hexadecanethiol self-assembled monolayer on Au. We have demonstrated that friction is primarily due to viscoelastic relaxations within the films, which give rise to contact hysteresis when deformation rates are within the ranges of 5 and 200 k. We observe that this contact hysteresis increases with exposure to air such that the friction coefficient increases from 0.004 to 0.075 when films are exposed to air for 40 days. Both hysteresis and friction increase with probe speed, and we present a model of friction that characterizes this speed dependence and which also predicts a linear dependence of friction on normal force in thin organic films. Finally, we identify several short-term wear regimes and identify that wear changes dramatically when fdms age.

Houston, J.E.; Kiely, J.D.

1998-10-14

260

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

261

Quantum loop programs  

E-print Network

Loop is a powerful program construct in classical computation, but its power is still not exploited fully in quantum computation. The exploitation of such power definitely requires a deep understanding of the mechanism of quantum loop programs. In this paper, we introduce a general scheme of quantum loops and describe its computational process. The notions of termination and almost termination are proposed for quantum loops, and the function computed by a quantum loop is defined. To show their expressive power, quantum loops are applied in describing quantum walks. Necessary and sufficient conditions for termination and almost termination of a general quantum loop on any mixed input state are presented. A quantum loop is said to be (almost) terminating if it (almost) terminates on any input state. We show that a quantum loop is almost terminating if and only if it is uniformly almost terminating. It is observed that a small disturbance either on the unitary transformation in the loop body or on the measurement in the loop guard can make any quantum loop (almost) terminating. Moreover, a representation of the function computed by a quantum loop is given in terms of finite summations of matrices. To illustrate the notions and results obtained in this paper, two simplest classes of quantum loop programs, one qubit quantum loops, and two qubit quantum loops defined by controlled gates, are carefully examined.

Mingsheng Ying; Yuan Feng

2006-05-25

262

Hidden hysteresis - population dynamics can obscure gene network dynamics  

PubMed Central

Background Positive feedback is a common motif in gene regulatory networks. It can be used in synthetic networks as an amplifier to increase the level of gene expression, as well as a nonlinear module to create bistable gene networks that display hysteresis in response to a given stimulus. Using a synthetic positive feedback-based tetracycline sensor in E. coli, we show that the population dynamics of a cell culture has a profound effect on the observed hysteretic response of a population of cells with this synthetic gene circuit. Results The amount of observable hysteresis in a cell culture harboring the gene circuit depended on the initial concentration of cells within the culture. The magnitude of the hysteresis observed was inversely related to the dilution procedure used to inoculate the subcultures; the higher the dilution of the cell culture, lower was the observed hysteresis of that culture at steady state. Although the behavior of the gene circuit in individual cells did not change significantly in the different subcultures, the proportion of cells exhibiting high levels of steady-state gene expression did change. Although the interrelated kinetics of gene expression and cell growth are unpredictable at first sight, we were able to resolve the surprising dilution-dependent hysteresis as a result of two interrelated phenomena - the stochastic switching between the ON and OFF phenotypes that led to the cumulative failure of the gene circuit over time, and the nonlinear, logistic growth of the cell in the batch culture. Conclusions These findings reinforce the fact that population dynamics cannot be ignored in analyzing the dynamics of gene networks. Indeed population dynamics may play a significant role in the manifestation of bistability and hysteresis, and is an important consideration when designing synthetic gene circuits intended for long-term application. PMID:23800122

2013-01-01

263

A survey on hysteresis modeling, identification and control  

NASA Astrophysics Data System (ADS)

The various mathematical models for hysteresis such as Preisach, Krasnosel'skii-Pokrovskii (KP), Prandtl-Ishlinskii (PI), Maxwell-Slip, Bouc-Wen and Duhem are surveyed in terms of their applications in modeling, control and identification of dynamical systems. In the first step, the classical formalisms of the models are presented to the reader, and more broadly, the utilization of the classical models is considered for development of more comprehensive models and appropriate controllers for corresponding systems. In addition, the authors attempt to encourage the reader to follow the existing mathematical models of hysteresis to resolve the open problems.

Hassani, Vahid; Tjahjowidodo, Tegoeh; Do, Thanh Nho

2014-12-01

264

A compensation method for the hysteresis error of DVD VCM  

NASA Astrophysics Data System (ADS)

The present study considers an autofocusing laser probe system used for the measurement of the surface profile and roughness of an object. The system is based upon a modified pickup head of a commercially available DVD player which uses a voice coil motor (VCM) to drive an objective lens during the autofocusing process. It is known that hysteresis of the VCM during the autofocusing process reduces the precision of the measurement results. Consequently, the present investigation adopts a hysteresis model to develop a compensation method which can improve the accuracy of the optical pickup head within the measurement system.

Chu, Chih-Liang; Fan, Kuang-Chao; Chen, Ye-Jing

2004-04-01

265

Wave interaction in acoustic resonators with and without hysteresis.  

PubMed

Nonlinear interaction of counterpropagating waves in solids is considered by using a general approach taking into account only the cumulative (resonant) nonlinear perturbations giving a nonzero contribution over the period and, consecutively, potentially able to significantly modify the linear solution. Different stress-strain relations are addressed, including those with hysteresis which serve as basic models for the recent acoustic experiments with rock and metals. An important case of the interaction of counterpropagating waves with close amplitudes in a high-Q resonator (bar) with hysteresis is specially addressed and compared with the case of a ring resonator. PMID:15658687

Ostrovsky, Lev A

2004-12-01

266

Large-scale separation and hysteresis in cascades  

NASA Technical Reports Server (NTRS)

An approach using a two-dimensional thin aerofoil, allied with the theory of viscous bluff-body separation, is used to study the initial cross-over from massive separation to an attached flow in a single-row unstaggered cascade. Analytic solutions are developed for the limit of small cascade-spacing. From the analytic solutions several interesting features of the cascade are examined, including multiple-solution branches and multiple regions of hysteresis. In addition, numerical results are presented for several selected aerofoils. Some of the aerofoils are found to contain markedly enlarged regions of hysteresis for certain critical cascade spacings.

Rothmayer, A. P.; Smith, F. T.

1985-01-01

267

Modeling of Switching and Hysteresis in Molecular Transport  

NASA Technical Reports Server (NTRS)

The conventional way of modeling current transport in two and three terminal molecular devices could be inadequate for certain cases involving switching and hysteresis. Here we present an alternate approach. Contrary to the regular way where applied bias directly modulates the conducting energy levels of the molecule, our method introduces a nonlinear potential energy surface varying with the applied bias as a control parameter. A time-dynamics is also introduced properly accounting for switching and hysteresis behavior. Although the model is phenomenological at this stage, we believe any detailed model would contain similar descriptions at its core.

Samanta, Manoj P.; Partridge, Harry (Technical Monitor)

2002-01-01

268

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

269

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); Jayajit Das (Massachusetts Institute of Technology; Department of Chemical Engineering; REV); Julie Zikherman (University of California; Department of Medicine; REV); Ming Yang (Massachusetts Institute of Technology; Department of Chemical Engineering; REV); Christopher C. Govern (Massachusetts Institute of Technology; Department of Chemical Engineering; REV); Mary Ho (University of California; Department of Anatomy; REV)

2009-04-14

270

Influence Factors on Critical Speed Hysteresis in Railway Vehicles  

Microsoft Academic Search

This research has been performed to estimate the hunting motion hysteresis of railway passenger cars. An old and a new car with almost the same structure are chosen for analysis models. To solve a set of simultaneous equations of motion that are strongly coupled with creep relations effectively, a shooting algorithm in which the nonlinear relations are regarded as a

Woo-Jin Chung; Jae-Kyung Shim

2003-01-01

271

A compensation method for the hysteresis error of DVD VCM  

Microsoft Academic Search

The present study considers an autofocusing laser probe system used for the measurement of the surface profile and roughness of an object. The system is based upon a modified pickup head of a commercially available DVD player which uses a voice coil motor (VCM) to drive an objective lens during the autofocusing process. It is known that hysteresis of the

Chih-Liang Chu; Kuang-Chao Fan; Ye-Jing Chen

2004-01-01

272

PID Control of Second-Order Systems with Hysteresis  

E-print Network

Ryan Department of Mathematical Sciences University of Bath Bath BA2 7AY, UK May 2007 Revised: October]. By contrast, in this paper we deal with a large class of rate-independent causal hysteresis operators which/01 Corresponding author, e-mail: hl@maths.bath.ac.uk 2 #12;in [12, 13] which ensure existence, regularity

Ryan, E.P.

273

The back transition and hysteresis effects in DIII-D  

SciTech Connect

The back transition from H-mode to L-mode has been studied on DIII-D as a part of the investigation of the L-H transition power threshold scaling. Based on a density-dependent scaling for the H-mode power threshold, ITER will require substantial hysteresis in this parameter to remain in H-mode as n{sub e} rises. Defining the hysteresis in terms of the ratio of sustaining to threshold power, P{sub HL}/P{sub LH} may need to be as small as 50% for ITER. Operation of DIII-D at injection powers slightly above the H-mode threshold results in an oscillatory behavior with multiple forward-backward transitions in the course of a discharge. These discharges represent a unique system for studying various control parameters that may influence the H{leftrightarrow}L state transition. Careful analysis of the power flow through the edge gives values for the sustaining power which are well below the corresponding threshold powers (P{sub HL}/P{sub LH} = 35--70%), indicating substantial hysteresis can be achieved in this parameter. Studies of other control parameter candidates such as edge temperature during the back transitions are less clear: the amount of hysteresis seen in these parameters, if any, is primarily dependent on the nature (ELMing, ELM-free) of the parent H-state.

Thomas, D.M.; Groebner, R.J.; Burrell, K.H.; Osborne, T.H.; Carlstrom, T.N. [General Atomics, San Diego, CA (United States)

1997-09-01

274

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 design. i #12; 1 Introduction Piezoelectric materials provide the capability for designing actuators piezoelectric effects. As a result of the ferroelectric nature of the materials, they also exhibit varying

275

Nonlinear Reptation in Molecular Based Hysteresis Models for Polymers  

E-print Network

direction involves exploration of multiscale aspects of polymeric structural modeling with uncertaintyNonlinear Reptation in Molecular Based Hysteresis Models for Polymers H.T. Banks and Negash G. Medhin Center for Research in Scientific Computation North Carolina State University Raleigh, NC 27695

276

Parameter Estimation Techniques for a Polarization Hysteresis Model  

E-print Network

formulations [1, 2, 12, 19], and (iii) domain wall models [6, 8, 11, 14, 15]. The first two are formulated as integral equations whereas the domain wall models are typically posed as differential equations techniques for models quantifying hysteresis and constitutive nonlinearities in ferroelectric materials

277

Parameter Estimation Techniques for a Class of Nonlinear Hysteresis Models  

E-print Network

energy models [8,10,18­20,24,25], Preisach formulations [2,3,5,7,16,26], and domain wall models [6,8,14,21,22]. As detailed in [17], the domain wall framework is efficient to implement but requires a priori knowledge hysteresis and constitutive nonlinearities inherent to ferroelectric, ferromagnetic and ferroelastic

278

Test Analysis and Calculation of Polyphase Hysteresis Motors  

Microsoft Academic Search

This paper presents a method of analyzing hysteresis motors for their parameters, gross power, losses and magnetizing ampere turns. A method is shown for calculating performance from either calculated or tested parameters. A synthesis method is given for determining rotor ring thickness.

P. H. Trickey

1972-01-01

279

Modeling and optimum design of disk-type hysteresis motors  

Microsoft Academic Search

In this paper, calculation of electrical equivalent circuit parameters versus design parameters of high frequency disk-type hysteresis motors are presented in details for steady state operating conditions. It is demonstrated that some of the equivalent circuit parameters alter significantly with input voltage and for different operating conditions. Therefore an equivalent circuit with fixed elements may give an inaccurate prediction of

Ahmad Darabi; Hamid Lesani; Teimoor Ghanbari; A. Akhavanhejazi

2007-01-01

280

An Analysis of the Hysteresis Motor Part III: Parasitic Losses  

Microsoft Academic Search

A major constraint on the performance prediction of a hysteresis machine arises from the parasitic losses associated with the rotor magnetic material. These losses can be high enough to absorb much of the developed torque, particularly for small sizes and large numbers of poles. In this paper the phenomena which cause parasitic losses are examined in detail. Analytical expressions are

M. A. Rahman; Miles Copeland; Gordon Slemon

1969-01-01

281

ASYNCHRONOUS PERFORMANCE OF HYSTERESIS MOTOR CONSIDERING EDDY-CURRENT EFFECTS  

Microsoft Academic Search

A simplified model of the hysteresis motor is introduced, with eddy-current effects taken into consideration. The field analysis is based on Maxweell's equations; the output relations, such as forces, power and heat losses, are derived via Maxwell's stress tensor and Poynting's theorem, and a special variant of the circle diagram is proposed.

S. GAVRIL; A. MOR

1983-01-01

282

Subsynchronous torque calculation in a shaded pole hysteresis motor  

Microsoft Academic Search

This paper deals with the synchronous dips in the torque-speed characteristic of a shaded pole hysteresis motor. The case under consideration is that of the synchronous dip related to the third harmonic of the air-gap field. First we show that the torque Varies between a maximum and a minimum value when the motor runs at one third of synchronous speed

J. Perard; M. Poloujadoff

1976-01-01

283

Design Optimization of Multistack Coreless Disk-Type Hysteresis Motor  

Microsoft Academic Search

Coreless dual disks hysteresis motors (CDDHM) have been recently introduced. The CDDHM presents some improve- ments in power factor and efficiency compared to general hystere- sis machines. However, there is not much design or manufacturing experience available and an initial design methodology has not yet been proposed for the new machine. According to this and existing inherent complexity in the

Ahmad Darabi; Mohammad Hossein Sadeghi; Amir Hassannia

2011-01-01

284

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

285

Sensor Saturation for Hysteresis Reduction in GMR Magnetometers  

E-print Network

Sensor Saturation for Hysteresis Reduction in GMR Magnetometers Philip S. Mease and Robert R technologies for the development of general-purpose magnetometers. They are applicable for both AC and DC of a magnetic field and instruments that make this measurement are known as magnetometers. The most common

Krchnavek, Robert R.

286

A Differential Model of Adsorption Hysteresis with Applications to Chromatography  

E-print Network

A Differential Model of Adsorption Hysteresis with Applications to Chromatography M. Peszy- ena occuring in chromatography or other related disciplines, see [21]. These models have the general rise in the beginning of 20th century, chromatography has become a wide industrial domain delivering

Peszynska, Malgorzata

287

Accounting for slow drainage and hysteresis in irrigation scheduling  

Microsoft Academic Search

Soils continue to drain for several days following irrigation. Water budgeting predictions can be improved by accounting for this, provided hysteresis is recognized in the “field capacity” condition. Uncertainty in this condition was evident in experiments comparing predicted soil water depletions with neutron probe measurements. Comparisons were made for potato, lettuce and calabrese crops, irrigated by hose-reel machine. Best agreement

M. E. Parkes; D. B. Naysmith; M. A. McDowall

1989-01-01

288

Periodic solutions of a forced system with hysteresis.  

NASA Technical Reports Server (NTRS)

Hysteresis damping arising in an oscillatory system due to the phenomenon of slip damping analyzed by Goodman and Klumpp (1956) is considered. An idealized physical model is proposed, and the existence of certain periodic motions is investigated in a system with small forcing which are near the largest periodic motion in a corresponding unforced system. Periodic solutions of the forced system are obtained.-

Drew, J. H.

1972-01-01

289

Elastic guides reduce hysteresis effect in Belleville spring package  

NASA Technical Reports Server (NTRS)

Peripheral support guides that elastically flex with the slight breathing on radial displacement during actuation can greatly reduce the hysteresis present in a Belleville spring package. This technique provides a control device that enhances the precision of pressure regulating valves, pressure switches, and vacuum actuators.

Mc Glashan, W. F., Jr.; Toth, L. R.

1967-01-01

290

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. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25150947

Poltoratski, Sonia; Tong, Frank

2014-10-01

291

Model-based, closed-loop control of PZT creep for cavity ring-down spectroscopy  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

292

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

293

N E W P E R S P E C T I V E S Body size and fitness in Odonata, stabilising selection  

E-print Network

N E W P E R S P E C T I V E S Body size and fitness in Odonata, stabilising selection and a meta mating success to territorial males and greater fecundity to females. The focus of this paper to measures of lifetime mating success has been demonstrated only for three species of insect, all odonates

Fincke, Ola M.

294

Global distribution of solid and aqueous sulfate aerosols: Effect of the hysteresis of particle phase transitions  

NASA Astrophysics Data System (ADS)

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 on recent laboratory data. We find that the solids mass fraction on a sulfate basis is 0.34, partitioned as 93% ammonium sulfate, 6% letovicite, and 1% ammonium bisulfate. The fraction increases with altitude from 0.10 to 0.30 in the boundary layer to 0.60-0.80 in the upper troposphere. The dominance of solids in the upper troposphere arises in part from high sulfate neutralization, reflecting in our simulation a low retention efficiency of NH3 upon cloud freezing. High sulfate neutralization is consistent with the few available observations in the upper troposphere. High acidity with a dominant aqueous phase, however, can occur following volcanic eruptions. Seasonal variation of the solids mass fraction in both the lower and upper troposphere is modulated by emissions of NH3 from the terrestrial biosphere and biomass burning as well as by emissions of dimethylsulfide from the ocean biosphere. The timescale of phase transitions, as driven by changes in relative humidity, varies from 10 to 50 h in the boundary layer to 150-400 h in the upper troposphere. Omission of the hysteresis effect in the CTM by assuming that particle phase follows the lower side of the hysteresis loop increases the solids mass fraction from 0.34 to 0.56. An upper side assumption decreases the fraction to 0.17. Lower and upper side assumptions better approximate particle phase for high and low altitudes, respectively. Fluctuations in the CRH, which can be induced by other constituents in sulfate particles such as minerals or organic molecules, strongly affect the solids mass fraction in the boundary layer but not at higher altitudes. Further studies are needed to determine the effects of large solids mass fraction on heterogeneous chemistry and cirrus cloud formation.

Wang, Jun; Hoffmann, Andrew A.; Park, Rokjin J.; Jacob, Daniel J.; Martin, Scot T.

2008-06-01

295

Global distribution of solid and aqueous sulfate aerosols: effect of the hysteresis of particle phase transitions  

NASA Astrophysics Data System (ADS)

The partitioning between solid and aqueous phases of tropospheric sulfate-ammonium particles is simulated with a global 3D chemical transport model (CTM). The simulation explicitly accounts for the hysteresis of particle phase transitions by transporting aqueous sulfate and three solid sulfate forms (ammonium sulfate, letovicite, and ammonium bisulfate). Composition-dependent deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) are based on recent laboratory data. We find that the solids mass fraction on a sulfate basis is 0.34, partitioned as 93% ammonium sulfate, 6% letovicite, and 1% ammonium bisulfate. The solids mass fraction increases with altitude from 0.10-0.20 in the boundary layer to 0.60-0.80 in the upper troposphere. The dominance of solids in the upper troposphere arises in part from high sulfate neutralization, reflecting in our simulation a low retention efficiency of NH3 upon cloud freezing. High sulfate neutralization is consistent with the few available observations. High acidity with a dominant aqueous phase, however, can occur in the upper troposphere during volcanic eruptions. Seasonal variation of the solids mass fraction in global average is modulated by emissions of NH3 from the terrestrial biosphere and biomass burning and of dimethylsulfide from the ocean biosphere. The timescale of phase transitions as driven by changes in relative humidity varies from 10- 50 hr in the boundary layer to 150-400 hr in the upper troposphere. Omission of the hysteresis effect in global models by assuming that particle phase follows the lower side of the hysteresis loop increases the solids mass fraction from 0.34 to 0.56. An upper-side assumption decreases the fraction to 0.17. Lower- and upper-side assumptions better approximate particle phase for high and low altitudes, respectively. Fluctuations in the CRH, which can be induced by other constituents in sulfate particles such as minerals or organic molecules, strongly affect the solids mass fraction in the boundary layer but not at higher altitudes.

Wang, J.; Hoffmann, A. A.; Park, R.; Jacob, D. J.; Martin, S. T.

2007-12-01

296

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

297

Modeling and control with hysteresis and creep of ionic polymer-metal composite (IPMC) actuators  

Microsoft Academic Search

Hysteresis and creep hinder the effective use of IPMC in sensors and actuators. This paper proposes a hybrid model that can precisely portray hysteresis and creep in piezoelectric actuators, which is constructed by a Preisach operator with a piecewise uniform density function and creep operator. Then, the corresponding inverse models for both hysteresis and creep are developed. It studies online

Zhen Chen; Lina Hao; Dingyu Xue; Xinhe Xu; Yanmei Liu

2008-01-01

298

A Model for RateDependent Hysteresis in Piezoceramic Materials Operating at Low Frequencies  

E-print Network

A Model for Rate­Dependent Hysteresis in Piezoceramic Materials Operating at Low Frequencies Ralph contribute to hysteresis inherent to piezoelectric materials operating at low frequencies. While quasistatic the full capabilities of the materials. The model employed here quantifies the hysteresis in two steps

299

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-Andres, Angel

2013-01-01

300

Contact angle hysteresis generated by strong dilute defects.  

PubMed

Water on solid decorated with hydrophobic defects (such as micropillars) often stays at the top of the defects in a so-called fakir state, which explains the superhydrophobicity observed in such case, provided that the density of defects is small enough. Here we show that this situation provides an ideal frame for studying the contact angle hysteresis; the phase below the liquid is "perfect" and slippery (it is air), contrasting with pillars' tops whose edges form strong pining sites for the contact line. This model system thus allows us to study the hysteresis as a function of the density of defects and to compare it to the classical theory by Joanny and de Gennes, which is based on very similar hypothesis. PMID:19673137

Reyssat, Mathilde; Quéré, David

2009-03-26

301

Hysteresis Behaviors of Poly (Naphthalene Quinone) Radical Electrorheological Fluid  

NASA Astrophysics Data System (ADS)

As a potential electrorheological(ER) material, poly(naphthalene quinone) radical (PNQR) ER fluid was prepared, and its rheological behavior and hysteresis phenomenon were investigated. PNQR was synthesized by Friedel-Crafts acylation between naphthalene and phthalic anhydride, using zinc chloride as a catalyst at 256°C. A Physica rheometer equipped with a high voltage generator was used to measure the rheological properties of the ER fluids, which were prepared by dispersing PNQR in silicone oil at several particle concentrations. Shear stresses were observed to decrease as shear rate increased in the region of slow deformation rate. It was further found that ER fluid showed different hysteresis behaviors according to the shear rate ranges; thixotropy was observed in the low shear rate region (0.007-0.51/s) and anti-thixotropy in the high shear rate region (0.5-10001/s). Controlled shear stress mode was also applied to observe similar behaviors.

Choi, Hyoung J.; Cho, Min S.; Jhon, Myung S.

302

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

303

Two liquids wetting and low hysteresis electrowetting on dielectric applications.  

PubMed

This study focuses on electrowetting using two immmiscible liquids on a dielectric coating. It is demonstrated that low contact angle of oil on the hydrophobic surfaces is a key parameter to obtain a low hysteresis system, below 2 degrees . On the basis of these results, three aspects of the wetting properties have been studied: the influence of the surface hydrophobic properties, the design of the liquids according to the hydrophobic surface, and a graphical method to solve the Bartell-Osterhof equation and predict the wetting properties of two liquids on a surface. These results define clear design rules to obtain a low hysteresis system, useful for many applications from liquid lenses to displays and laboratory-on-a-chip. PMID:19459706

Maillard, Mathieu; Legrand, Julien; Berge, Bruno

2009-06-01

304

Hysteresis in swelling and in sorption of wood tissue.  

PubMed

The swelling and shrinkage of four Picea abies (L. Karst) wood tissue homogeneous samples, of porosity varying between 45% and 78%, is documented with high-resolution synchrotron radiation phase-contrast X-ray tomographic microscopy. We report measurements of the reversible moisture-induced orthotropic swelling/shrinkage strains. Hysteresis is observed when the swelling/shrinkage strain is considered as a function of relative humidity, except for the very high porosity sample. Hysteresis is no longer present when swelling/shrinkage strains are considered versus moisture content, indicating that wood deforms to the same extent whether an amount of moisture is desorbed or adsorbed. Furthermore, swelling anisotropy, in the tangential and radial directions, is found to increase with increasing porosity. The most homogeneous behaviour for a group of cells is found for 30-50 cells, smaller/larger groups having higher orders of variations. PMID:23523731

Patera, Alessandra; Derome, Dominique; Griffa, Michele; Carmeliet, Jan

2013-06-01

305

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

306

Ignition, extinction, and thermal hysteresis of a heterogeneous exothermic reaction  

Microsoft Academic Search

Critical conditions of ignition and extinction are studied theoretically for the case of a heterogeneous exothermic reaction\\u000a proceeding on the uniformly accessible surface of a channel or a pore. Particular emphasis is placed on the thermal-hysteresis\\u000a effect of the reaction (an ignition temperature in excess of the extinction temperature), which ensures stability of the reaction\\u000a against changes in the external

I. G. Assovskii

1998-01-01

307

Applications of hysteresis switching in parameter adaptive control  

Microsoft Academic Search

The hysteresis switching algorithm of R.H. Middleton et al. (ibid., vol.33, no.1, p.50-8, Jan. 1988) is reexamined in a broader context. To demonstrate its utility, the algorithm is applied to various families of identifier-based parameterized controllers of both the direct and indirect control types. Application to the direct control type results in a model reference adaptive controller capable of stabilizing,

A. Stephen Morse; David Q. Mayne; Graham C. Goodwin

1992-01-01

308

Equivalent Circuits for Single-Phase Induction and Hysteresis Motors  

Microsoft Academic Search

General steady-state equivalent circuits are derived for the family of single-phase motors with unequal contrarotating magnetic fields produced by one or two stator windings and\\/or stator saliency, and rotor torque due to hysteresis and\\/or eddy- current action. The derivation of an equivalent quadrature motor, first shown by Kron, is extended to the range of motors under consideration. The idealized treatment

Denis O'Kelly

1971-01-01

309

TRANSIENT PERFORMANCE ANALYSIS OF POLYPHASE HYSTERESIS-RELUCTANCE MOTORS  

Microsoft Academic Search

This paper presents some important aspects of the run-up characteristics of polyphase hysteresis-reluctance motors. Analysis to predict the transient and asynchronous performances of these type of motors are presented. A general equivalent circuit model is developed for the sub-synchronous mode of operation. The experimental rotor was made of 36% cobalt-steel alloys and tested by using a stator of polyphase generalized

M. A. RAHMAN; A. M. OSHEIBA

1984-01-01

310

Vector hysteresis measurements via a single disk tester  

NASA Astrophysics Data System (ADS)

In this paper we present a single disk tester (SDT) developed for vector hysteresis measurements of magnetic steels. The measurement system deals with a stator of a 3-phase induction motor and some suitable magnetic field and magnetic induction probes. Numerical calculations based to a FEM approach in time domain and experimental tests are shown in order to describe both accuracy and efficiency of this measurement system.

Cardelli, E.; Faba, A.

2006-02-01

311

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

312

Novel thermal hysteresis proteins from low temperature basidiomycete, Coprinus psychromorbidus.  

PubMed

The low temperature basidiomycete, Coprinus psychromorbidus, produced three kinds of thermal hysteresis proteins (THPs) in the extracellular space. Molecular mass of purified fungal THPs were approximately 23 kDa, respectively, however those fungal THPs had different N-terminal amino acid sequences. Those fungal THPs formed ice crystals resembling "stone Age arrow head". These observations indicate that fungal THPs did not form hexagonal ice crystals to inhibit its growth. PMID:12908023

Hoshino, T; Kiriaki, M; Nakajima, T

2003-01-01

313

Muscle hysteresis and movement control: a theoretical study.  

PubMed

In this study we have tried to elaborate necessary theoretical approaches for the adequate analysis of the central motor commands to a mammalian muscle in the equilibrium states and during transition movements between these states. At present, the equilibrium point hypothesis has obtained a wide distribution in this field. The muscle is considered in the framework of the theory as an executive element of the reflex circuits originating in the muscle proprioceptors and being closed at the level of spinal cord and the supraspinal motor centres. The main parameter defining the muscle state is supposed to be the threshold of the stretch reflex--the minimal length value at which muscle begins to resist to the externally applied force. We have attempted to show that the theory has an essential shortcoming because it does not take into account such important non-linearity in the muscle behaviour as hysteresis. In the framework of the equilibrium point hypothesis, the muscle behaviour within the stretch reflex system does not depend on movement direction. The stretch and unloading reflexes are supposed to have the same length tension dependencies when the muscle is stretching or contracting with a rather slow velocity. However, powerful hysteresis of the stretch reflex system requires taking into account the direction of the current movement, the after-effects of previous movement led to a principal uncertainty in the muscle steady-state. We would like to stress that any process of active muscle shortening should be controlled by dynamic components in efferent inflow. At the same time, the resulting steady-state develops by using effective hysteresis mechanism for its maintenance. The following hypothesis was proposed to explain the length clamping mechanisms in shortening transition movements. A significant decrement of the arrived efferent activity at the phase of the length fixation can evoke an internal elongation of the contractile elements within the muscle and corresponding hysteresis-like enhancement of the contractile effectiveness. Hence, instead of considering the quasi-static and dynamic components of movement commands as in the equilibrium point hypothesis, it is preferable to adopt a model of the shared coding of both the final position and movement velocity. The dynamic component of the efferent discharge seems to be required for a complete definition of the final steady-state, but maintenance of the state is closely associated with energetically advantageous hysteresis mechanisms. It was concluded that the dynamic phase of efferent activity should play an extremely important role in the central coding of the real movements produced, in particular, by contraction of agonists in the absence of antagonist activation. PMID:9466419

Kostyukov, A I

1998-03-01

314

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

NASA Astrophysics Data System (ADS)

6-81.3 Mo permalloy, developed in the 1960s for use in high performance ring-core fluxgate sensors, remains the state-of-the-art for permalloy-cored fluxgate magnetometers. The magnetic properties of 6-81.3, namely magnetocrystalline and magnetoelastic anisotropies and saturation induction are all optimum in the Fe-Ni-Mo system. In such polycrystalline permalloy fluxgate sensors a single phenomenon may cause both fluxgate noise and magnetic hysteresis, explain Barkhausen jumps, remanence and coercivity, and avoid domain denucleation. The phenomenon, domain wall reconnection, is presented as part of a theoretical model. In the unmagnetized state a coarse-grain high-quality permalloy foil ideally forms stripe domains, which present at the free surface as parallel, uniformly spaced domain walls that cross the entire thickness of the foil. Leakage flux "in" and "out" of alternating domains is a requirement of the random orientation, grain-by-grain, of magnetic easy axes' angles with respect to the foil free surface. Its magnetostatic energy 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 magnetostatic energy cost such a change would elicit. Thus domain walls are "pinned" to free surfaces. Driven to saturation, domain walls first bulge then reconnect via Barkhausen jumps to form a new domain configuration this author has called "channel domains", that are attached to free surfaces. The approach to saturation now continues as reversible channel domain compression. Driving the permalloy deeper into saturation compresses 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 H, thus explaining remanence. The Barkhausen jumps being irreversible exothermic events are sources of fluxgate noise, powered by the energy available from domain wall reconnection. A simplified domain energy model can then provide a predictive relation between ring core magnetic properties and fluxgate sensor noise power. Four properties are predicted to affect noise power, two of which, are well known: saturation total magnetic flux density and magnetic anisotropy. The two additional properties are easy axes alignment and foil thickness. Flux density and magnetic anisotropy are primary magnetic properties determined by an alloy's chemistry and crystalline lattice properties. Easy axes alignment and foil thickness are secondary, geometrical properties related to an alloy's polycrystalline fabric and manufacture. Improvements to fluxgate noise performance can in principle be achieved by optimizing any of these four properties in such a way as to minimize magnetostatic energy. Fluxgate signal power is proportional to B-H loop curvature (d2B/dH2). The degree to which Barkhausen jumps coincide with loop curvature is a measure of 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 reduced noise.

Narod, B. B.

2014-06-01

315

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

NASA Astrophysics Data System (ADS)

Developed in the 1960s for use in high-performance ring-core fluxgate sensors, 6-81.3 Mo permalloy remains the state of the art for permalloy-cored fluxgate magnetometers. The magnetic properties of 6-81.3, namely magnetocrystalline and magnetoelastic anisotropies and saturation induction, are all optimum in the Fe-Ni-Mo system. In such polycrystalline permalloy fluxgate sensors, a single phenomenon may cause both fluxgate noise and magnetic hysteresis; explain Barkhausen jumps, remanence and coercivity; and avoid domain denucleation. This phenomenon, domain wall reconnection, is presented as part of a theoretical model. In the unmagnetized state a coarse-grain high-quality permalloy foil ideally forms stripe domains, which present at the free surface as parallel, uniformly spaced domain walls that cross the entire thickness of the foil. Leakage flux "in" and "out" of alternating domains is a requirement of the random orientation, grain by grain, of magnetic easy axes' angles with respect to the foil free surface. Its magnetostatic energy 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 magnetostatic energy cost such a change would elicit. Thus domain walls are "pinned" to free surfaces. Driven to saturation, domain walls first bulge then reconnect via Barkhausen jumps to form a new domain configuration that I have called "channel domains", which are attached to free surfaces. The approach to saturation now continues as reversible channel domain compression. Driving the permalloy deeper into saturation compresses 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 H, thus explaining remanence. The Barkhausen jumps, being irreversible exothermic events, are sources of fluxgate noise powered by the energy available from domain wall reconnection. A simplified domain energy model can then provide a predictive relation between ring-core magnetic properties and fluxgate sensor noise power. Four properties are predicted to affect noise power, two of which are well known: saturation total magnetic flux density and magnetic anisotropy. The two additional properties are easy axes alignment and foil thickness. Flux density and magnetic anisotropy are primary magnetic properties determined by an alloy's chemistry and crystalline lattice properties. Easy axes alignment and foil thickness are secondary, geometrical properties related to an alloy's polycrystalline fabric and manufacture. Improvements to fluxgate noise performance can in principle be achieved by optimizing any of these four properties in such a way as to minimize magnetostatic energy. Fluxgate signal power is proportional to B - H loop curvature [d2B/dH2]. The degree to which Barkhausen jumps coincide with loop curvature is a measure of noise that accompanies the fluxgate signal. B - H loops with significant curvature beyond the open hysteresis loop may be used to advantage to acquire the fluxgate signal with reduced noise.

Narod, B. B.

2014-09-01

316

Vortex instability and hysteresis effects in I- V curves of superconducting Y 1Ba 2Cu 3O 7- ?  

NASA Astrophysics Data System (ADS)

We have investigated the effect of the current sweep rate (CSR) on the vortex dynamics in superconducting bulk sample of Y 1Ba 2Cu 3O 7- ?. It has been found that the CSR has several dramatic effects on the vortex motion by giving rise enhancement in dissipation as decreasing the CSR, significant time effects, and instabilities in current-voltage ( I- V) curves. The hysteresis loops concerning the I- V curves in both the current-increase and -decrease branches of the forward current region, and also the branches of the reversed current region have been observed together with a gradual diminutive of the hysteresis effects with decreasing the CSR. Due to the field and temperature domain considered, it is also observed that the moving state becomes unstable giving rise some instabilities such as small jumps and steps for both low and moderate current values as a function of CSR. Those anomalies have been discussed in terms of the depinning-pinning correlated to the plastic flow regime together with the disorder in the coupling strength between the superconducting grains, and compared qualitatively to the numerical computer simulations. In addition, for a given field and temperature domain, it has been shown that the CSR together with a relevant current scale is of importance in evolution of the I- V curves and is a useful tool in investigating the details of the vortex dynamics.

Kiliç, A.; Kiliç, K.; Çetin, O.

2003-02-01

317

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

318

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

319

Loop Quantum Cosmology.  

E-print Network

??In this thesis we present a detailedintroduction to loop quantum cosmologyfocusing on the Robertson-Walker cosmologieswith constant spatial curvature. The constructionof the quantum theory will be… (more)

Vandersloot, Kevin

2006-01-01

320

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

321

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

322

Basin of Attraction Determines Hysteresis in Explosive Synchronization  

NASA Astrophysics Data System (ADS)

Spontaneous explosive emergent behavior takes place in heterogeneous networks when the frequencies of the nodes are positively correlated to the node degree. A central feature of such explosive transitions is a hysteretic behavior at the transition to synchronization. We unravel the underlying mechanisms and show that the dynamical origin of the hysteresis is a change of basin of attraction of the synchronization state. Our findings hold for heterogeneous networks with star graph motifs such as scale-free networks, and hence, reveal how microscopic network parameters such as node degree and frequency affect the global network properties and can be used for network design and control.

Zou, Yong; Pereira, Tiago; Small, Michael; Liu, Zonghua; Kurths, Jürgen

2014-03-01

323

Mass Measurement System Using Relay Feedback with Hysteresis  

NASA Astrophysics Data System (ADS)

Mass measurement using a relay feedback system was studied experimentally. The measurement system has an on-off relay with hysteresis and switches force acting on the object in relation to its velocity. Such nonlinear control induces a limit cycle in the feedback system. The mass of the object is determined from the period of this limit cycle. The apparatus manufactured for experimental study uses two voice coil motors (VCM's), one of which is for driving the object and the other is for generating prescribed disturbances. The effects of system parameters and disturbances on measurement accuracy were examined experimentally.

Mizuno, Takeshi; Adachi, Takahiro; Takasaki, Masaya; Ishino, Yuji

324

Basin of Attraction Determines Hysteresis in Explosive Synchronization  

E-print Network

Spontaneous explosive emergent behavior takes place in heterogeneous networks when the frequencies of the nodes are positively correlated to the node degree. A central feature of such explosive transitions is a hysteretic behavior at the transition to synchronization. We unravel the underlying mechanisms and show that the dynamical origin of the hysteresis is a change of basin of attraction of the synchronization state. Our findings hold for heterogeneous networks with star graph motifs such as scale free networks, and hence reveal how microscopic network parameters such as node degree and frequency affect the global network properties and can be used for network design and control.

Yong Zou; Tiago Pereira; Michael Small; Zonghua Liu; Jürgen Kurths

2014-01-07

325

Hysteresis effects of changing the parameters of noncooperative games.  

PubMed

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. PMID:22587144

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

2012-03-01

326

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

327

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

328

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

329

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

330

Falling Loop Model  

NSDL National Science Digital Library

The EJS Falling Loop Model shows a conducting loop falling out of a uniform magnetic field. Users can change the size and orientation of the loop. If Ejs is installed, right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item allows for editing of the model. The Falling Loop model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_FallingLoop.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Cox, Anne

2009-09-24

331

Coreless Dual-rotor Disc Hysteresis Motor, Modeling, and Performance Prediction  

Microsoft Academic Search

Due to their robust structure, low and constant starting current, constant torque, and smooth and noiseless operation, small- and medium-sized power rating hysteresis motors are commonly employed in high-speed applications. However, hysteresis motors, in general, have a comparatively low power factor, efficiency, and torque density. In this article, a new structure, the coreless dual-rotor disc hysteresis motor, is introduced. Electromagnetic

Ahmad Darabi; Mohsen Sanati-Moghadam; Teymoor Ghanbari

2010-01-01

332

Modelling and analysis of a hysteresis motor used in space application  

Microsoft Academic Search

Summary form only given, as follows. We present the computer-aided modelling and analysis of a three-phase hysteresis synchronous motor used in the gyroscope as the gyro-rotor drive motor. A computer program is developed for the performance analysis of the hysteresis motor. The program accounts for all known losses in the hysteresis motor. The simulation program is tuned by incorporating the

K. R. Rajagopal; Christian Coltelli; Vasca Navale

2002-01-01

333

Experimental Investigation of the Pseudoelastic Hysteresis Damping Characteristics of Shape Memory Alloy Wires  

Microsoft Academic Search

An experimental investigation was conducted to determine the pseudoelastic hysteresis damping characteristics of Ni-Ti Shape Memory Alloy (SMA) wires. The comprehensive study examines the effects of cycling, oscillation frequency, strain amplitude, temperature, and static strain offset on the pseudoelastic stress-strain hysteresis of SMA wires under axial loading. Experimental data are obtained for complete austenite-martensite transformation hysteresis as well as partial

David Wolons; Farhan Gandhi; Brendon Malovrh

1998-01-01

334

Hysteresis zone or locus - Aerodynamic of bulbous based bodies at low speeds  

NASA Technical Reports Server (NTRS)

Experimental data are presented which seem to suggest that a well-defined hysteresis locus on bulbous based bodies at low speeds does not exist. Instead, if the experiment is repeated several times, the entire hysteresis region seems to fill with data rather than trace out a specific hysteresis locus. Data obtained on an oscillating model even at low reduced frequencies may be well defined but when applied to arbitrary motion lead to less accurate results than desired.

Covert, E. E.

1979-01-01

335

Magnetoresistance hysteresis in granular HTSCs as a manifestation of the magnetic flux trapped by superconducting grains in YBCO + CuO composites  

SciTech Connect

Hysterestic behavior of the magnetoresistance of granular HTSCs and its interaction with the magnetic hysteresis are studied by measuring magnetoresistance R(H) and critical current I{sub c}(H) of composites formed by HTSC Y{sub 0.75}Lu{sub 0.25}Ba{sub 2}Cu{sub 3}O{sub 7} and CuO. A network of Josephson junctions is formed in such composites, in which the nonsuperconducting component plays the role of barriers between HTSC grains. Hysteretic dependences R(H) of magnetoresistance are studied in a wide range of transport current density j and are analyzed in the framework of the two-level model of a granular superconductor, in which dissipation takes place in the Josephson medium and the magnetic flux can be pinned both in grains and in the Josephson medium. The interrelation between the hysteresis of critical current I{sub c}(H) and the evolution of the hysterestic dependence R(H) of the magnetoresistance upon transport current variation is demonstrated experimentally. The effect of the magnetic past history on the hysteretic behavior of R(H) and the emergence of a segment with a negative magnetoresistance are analyzed. It is shown for the first time that the R(H) dependences are characterized by a parameter that is independent of the transport current, viz., the width of the R(H) hysteresis loop.

Balaev, D. A., E-mail: smp@iph.krasn.ru; Gokhfeld, D. M.; Dubrovskii, A. A.; Popkov, S. I.; Shaikhutdinov, K. A.; Petrov, M. I. [Russian Academy of Sciences, Kirenskii Institute of Physics, Siberian Branch (Russian Federation)

2007-12-15

336

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

337

The capillary hysteresis model HYSTR: User`s guide  

SciTech Connect

The potential disposal of nuclear waste in the unsaturated zone at Yucca Mountain, Nevada, has generated increased interest in the study of fluid flow through unsaturated media. In the near future, large-scale field tests will be conducted at the Yucca Mountain site, and work is now being done to design and analyze these tests. As part of these efforts a capillary hysteresis model has been developed. A computer program to calculate the hysteretic relationship between capillary pressure {phi} and liquid saturation (S{sub 1}) has been written that is designed to be easily incorporated into any numerical unsaturated flow simulator that computes capillary pressure as a function of liquid saturation. This report gives a detailed description of the model along with information on how it can be interfaced with a transport code. Although the model was developed specifically for calculations related to nuclear waste disposal, it should be applicable to any capillary hysteresis problem for which the secondary and higher order scanning curves can be approximated from the first order scanning curves. HYSTR is a set of subroutines to calculate capillary pressure for a given liquid saturation under hysteretic conditions.

Niemi, A.; Bodvarsson, G.S.

1991-11-01

338

Hysteresis of soft joints embedded with fluid-filled microchannels.  

PubMed

Many arthropods are known to achieve dynamic stability during rapid locomotion on rough terrains despite the absence of an elaborate nervous system. While muscle viscoelasticity and its inherent friction have been thought to cause this passive absorption of energy, the role of embedded microstructures in muscles and muscle joints has not yet been investigated. Inspired by the soft and flexible hinge joints present in many of these animals, we have carried out displacement-controlled bending of thin elastic slabs embedded with fluid-filled microchannels. During loading, the slab bends uniformly to a critical curvature, beyond which the skin covering the channel buckles with a catastrophic decrease in load. In the reverse cycle, the buckled skin straightens out but at a significantly lower load. In such a loading-unloading cycle, this localized buckling phenomenon results in a dynamic change in the geometry of the joint, which leads to a significant hysteresis in elastic energy. The hysteresis varies nonlinearly with channel diameters and thicknesses of the slab, which is captured by a simple scaling analysis of the phenomenon. PMID:18611846

Ghatak, Animangsu; Majumder, Abhijit; Kumar, Rajendra

2009-02-01

339

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

340

Hysteresis analysis for the permanent magnet assisted synchronous reluctance motor by coupled FEM and Preisach modelling  

SciTech Connect

In high speed applications of PMASynRM, hysteresis losses can become the major cause of power dissipation. Therefore, whereas in other kind of machines a rough estimation of hysteresis can be accepted, their importance in PMASynRM justifies a greater effort in calculating them more precisely. This study investigates the hysteresis phenomena of the Permanent Magnet Assisted Synchronous Reluctance Motor (PMASynRM) using coupled FEM and Preisach modelling. Preisach's model, which allows accurate prediction of hysteresis, is adopted in this procedure to provide a nonlinear solution. The computer simulation and experimental result for the i-[lambda] loci show the propriety of the proposed method.

Lee, J.H.; Hyun, D.S. (Hanyang Univ., Seoul (Korea, Republic of). Dept. of Electrical Engineering)

1999-05-01

341

Mutational analysis of the conserved TGES loop of sarcoplasmic reticulum Ca2+-ATPase.  

PubMed

Crystal structures have shown that the conserved TGES loop of the Ca2+-ATPase is isolated in the Ca2E1 state but becomes inserted in the catalytic site in E2 states. Here, we have examined the kinetics of the partial reaction steps of the transport cycle and the binding of the phosphoryl analogs BeF, AlF, MgF, and vanadate in mutants with alterations to the TGES residues. The mutations encompassed variation of size, polarity, and charge of the side chains. Differential effects on the Ca2E1P --> E2P, E2P --> E2, and E2 --> Ca2E1 reactions and the binding of the phosphoryl analogs were observed. In the E183D mutant, the E2P --> E2 dephosphorylation reaction proceeded at a rate as high as one-third that of the wild type, whereas it was very slow in the other Glu183 mutants, including E183Q, thus demonstrating the need for a negatively charged carboxylate group to catalyze dephosphorylation. By contrast, the Ca2E1P --> E2P transition was accomplished at a reasonable rate with glutamine in place of Glu183, but not with aspartate, indicating that the length of the Glu183 side chain, in addition to its hydrogen bonding potential, is critical for Ca2E1P --> E2P. This transition was also slowed in mutants with alteration to other TGES residues. The data provide functional evidence in support of the proposed role of Glu183 in activating the water molecule involved in the E2P --> E2 dephosphorylation and suggest a direct participation of the side chains of the TGES loop in the control and facilitation of the insertion of the loop in the catalytic site. The interactions of the TGES loop furthermore seem to facilitate its disengagement from the catalytic site during the E2 --> Ca2E1 transition. PMID:16893884

Anthonisen, Anne Nyholm; Clausen, Johannes D; Andersen, Jens Peter

2006-10-20

342

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

2006-03-17

343

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

344

Natively Unstructured Loops Differ from Other Loops  

PubMed Central

Natively unstructured or disordered protein regions may increase the functional complexity of an organism; they are particularly abundant in eukaryotes and often evade structure determination. Many computational methods predict unstructured regions by training on outliers in otherwise well-ordered structures. Here, we introduce an approach that uses a neural network in a very different and novel way. We hypothesize that very long contiguous segments with nonregular secondary structure (NORS regions) differ significantly from regular, well-structured loops, and that a method detecting such features could predict natively unstructured regions. Training our new method, NORSnet, on predicted information rather than on experimental data yielded three major advantages: it removed the overlap between testing and training, it systematically covered entire proteomes, and it explicitly focused on one particular aspect of unstructured regions with a simple structural interpretation, namely that they are loops. Our hypothesis was correct: well-structured and unstructured loops differ so substantially that NORSnet succeeded in their distinction. Benchmarks on previously used and new experimental data of unstructured regions revealed that NORSnet performed very well. Although it was not the best single prediction method, NORSnet was sufficiently accurate to flag unstructured regions in proteins that were previously not annotated. In one application, NORSnet revealed previously undetected unstructured regions in putative targets for structural genomics and may thereby contribute to increasing structural coverage of large eukaryotic families. NORSnet found unstructured regions more often in domain boundaries than expected at random. In another application, we estimated that 50%–70% of all worm proteins observed to have more than seven protein–protein interaction partners have unstructured regions. The comparative analysis between NORSnet and DISOPRED2 suggested that long unstructured loops are a major part of unstructured regions in molecular networks. PMID:17658943

Schlessinger, Avner; Liu, Jinfeng; Rost, Burkhard

2007-01-01

345

Water adsorption in disordered mesoporous silica (Vycor) at 300 K and 650 K: A Grand Canonical Monte Carlo simulation study of hysteresis  

NASA Astrophysics Data System (ADS)

This numerical simulation paper focuses on the adsorption/desorption of water in disordered mesoporous silica glasses (Vycor-like). The numerical adsorbent was previously obtained by off lattice method, and was shown to reproduce quite well the micro- and mesotextural properties of real Vycor, as well as morphological (pore size distribution) and topological (pore interconnections) disorder. The water-water interactions are described by the SPC model while water-silica interactions are calculated in the framework of the PN-TrAZ model. The water adsorption/desorption isotherms and the configurational energies are calculated by the Grand Canonical Monte Carlo simulation method. The low pressure results compare well with experiments, showing the good transferability of the intermolecular potential. It is shown that if the hysteresis loop observed in the adsorption/desorption isotherm is considered as a true phase transition (which is actually still an open question in the case of disordered porous materials), then it is possible to calculate the grand potential by applying the thermodynamic integration scheme. The grand potential is shown to be multivalued for low (subcritical) temperature, and continuous for high (supercritical) temperature. A coexistence point is found within the hysteresis loop, actually close to the vertical desorption line. Below the equilibrium chemical potential, the gaslike branch is stable whereas the liquidlike branch is metastable. The situation is reversed above the coexistence point.

Puibasset, Joël; Pellenq, Roland J.-M.

2005-03-01

346

A loop quantum multiverse?  

NASA Astrophysics Data System (ADS)

Inhomogeneous space-times in loop quantum cosmology have come under better control with recent advances in effective methods. Even highly inhomogeneous situations, for which multiverse scenarios provide extreme examples, can now be considered at least qualitatively.

Bojowald, Martin

2013-02-01

347

Diffusion of Wilson Loops  

E-print Network

A phenomenological analysis of the distribution of Wilson loops in SU(2) Yang-Mills theory is presented in which Wilson loop distributions are described as the result of a diffusion process on the group manifold. It is shown that, in the absence of forces, diffusion implies Casimir scaling and, conversely, exact Casimir scaling implies free diffusion. Screening processes occur if diffusion takes place in a potential. The crucial distinction between screening of fundamental and adjoint loops is formulated as a symmetry property related to the center symmetry of the underlying gauge theory. The results are expressed in terms of an effective Wilson loop action and compared with various limits of SU(2) Yang-Mills theory.

A. M. Brzoska; F. Lenz; J. W. Negele; M. Thies

2004-12-01

348

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

349

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.

350

Inferring Pore Size and Network Structure from Sorption Hysteresis  

E-print Network

Sorption experiments are widely used to infer the pore size distribution of a mesoporous material. We present a simple model that explains the hysteresis observed on desorption in such experiments. The model is based on well-established relationships between the radius of a pore and the partial pressure at which it will fill, but additionally describes of the connectivity of the pore network. The model is able to explain both primary and scanning sorption isotherms for a range of materials with wide pore size distributions, such as cement paste and dental enamel. It allows quantification of the prevalence of macropores in the material, even though these pores are never filled during the sorption experiments. A distinct bump in the desorption isotherms is attributed to spinodal decomposition (or cavitation) at a partial pressure that depends on temperature, and experiments across a range of sorbents and sorbates are consistent with a universal scaling.

Matthew B. Pinson; Hamlin M. Jennings; Martin Z. Bazant

2014-02-14

351

Oscillatory activity in cells: multi-stability and hysteresis  

NASA Astrophysics Data System (ADS)

Oscillatory activity of cells has been the topic of many studies. Oscillatory activity can be due to action potential firing corresponding to the well-known Hodgkin-Huxley (HH) type dynamics of ion-channels in the cell membrane or due to IP3-mediated calcium oscillations in the endoplasmic reticulum (ER) causing periodic oscillations of calcium transients in the cytosol. In this study we show that coupling of these two oscillatory mechanisms may reveal a complex, rich spectrum of both stable and unstable states of cells with hysteresis. The predicted bi-stability corresponds to experimentally observed states. This illustrates that the different behavior of cells is not the consequence of differentiation in cells with different properties, but rather reflects different states of a single cell type.

Kusters, J. M. A. M.; Cortes, J. M.; van Meerwijk, W. P. M.; Ypey, D. L.; Theuvenet, A. P. R.; Gielen, C. C. A. M.

2007-02-01

352

Hysteresis and Contact forces in a Gas-fluidized Bed  

NASA Astrophysics Data System (ADS)

A gas-fluidized bed consists of an assembly of granular material fluidized by an upflow of gas. The "melting" of a static assembly of sand to the fluid state is hysteretic and proceeds through an intermediate state known as the "uniform fluid" which we have recently shown(Menon, N.; Durian, D.J. Particle motions in a gas-fluidized bed of sand. Phys. Rev. Lett., vol.79, 3407 (1997)) to be a weak, but motionless solid with enduring contacts between grains. We characterize the contact forces that stabilize this phase by measurements of the hysteresis in gas pressure vs gas velocity measurements and analyze them in terms of a yield stress for this soft solid. Since the chains of contact forces terminate at the boundaries of the bed, interesting boundary effects are anticipated. We probe finite-size effects in the magnitude of these forces obtained both by varying grain-size as well as aspect ratio of the bed.

Menon, Narayanan; Durian, Douglas

1998-03-01

353

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

354

Hysteresis multicycles in nanomagnet arrays J. M. Deutsch, Trieu Mai, and Onuttom Narayan  

E-print Network

. INTRODUCTION Hysteresis in magnets 1,2 is a paradigm for all history dependent behavior in nature 3­5 . In addition, hysteresis is the cornerstone of the magnetic data storage industry, and of great technological- graph was measured. Whether a multicycle is present, and if so, its order, depended on the realization

California at Santa Cruz, University of

355

Observations of an Impurity-driven Hysteresis Behavior in Ice Crystal Growth at Low Pressure  

E-print Network

Observations of an Impurity-driven Hysteresis Behavior in Ice Crystal Growth at Low Pressure Abstract. We describe observations of a novel hysteresis behavior in the growth of ice crystals under near the growth velocity vn normal to the surface of a crystal facet in terms of the Hertz-Knudsen formula vn

Libbrecht, Kenneth G.

356

Adaptive hysteresis band current control for transformerless single-phase PV inverters  

Microsoft Academic Search

Current control based on hysteresis algorithms are widely used in different applications, such as motion control, active filtering or active\\/reactive power delivery control in distributed generation systems. The hysteresis current control provides to the system a fast and robust dynamic response, and requires a simple implementation in standard digital signal platforms. On the other hand, the main drawback of classical

Gerardo Vázquez; Pedro Rodriguez; Rafael Ordoñez; Tamás Kerekes; Remus Teodorescu

2009-01-01

357

Physiological thermoregulation in a crustacean? Heart rate hysteresis in the freshwater crayfish Cherax destructor  

Microsoft Academic Search

Differential heart rates during heating and cooling (heart rate hysteresis) are an important thermoregulatory mechanism in ectothermic reptiles. We speculate that heart rate hysteresis has evolved alongside vascularisation, and to determine whether this phenomenon occurs in a lineage with vascularised circulatory systems that is phylogenetically distant from reptiles, we measured the response of heart rate to convective heat transfer in

Jacqueline E. Goudkamp; Frank Seebacher; Mark Ahern; Craig E. Franklin

2004-01-01

358

Temperature hysteresis of the domain structure of single-axis ferrimagnets  

Microsoft Academic Search

The temperature hysteresis of the domain structure of thin layers of single-axis ferrimagnets has been studied theoretically and experimentally varying the temperature. The relationships have been found for the qualitative description of the magnitude of the temperature hysteresis of the period of a band domain structure. The results of the calculation are in satisfactory agreement with experimental data obtained on

V. E. Ivanov; G. S. Kandaurova; E. F. Ledovskaya

1988-01-01

359

Analysis and microprocessor implementation of field oriented control for permanent magnet hysteresis synchronous motor  

Microsoft Academic Search

An analytical motor for a permanent magnet hysteresis hybrid synchronous motor has been developed. A microprocessor-based field oriented control scheme has been successfully experimented for a laboratory magnet hysteresis motor. A scheme for measuring the torque angle is proposed. The test results confirm the improvement of the dynamic performances using a field-oriented control strategy

J. Qian; M. Azizur Rahman

1991-01-01

360

Numerical and experimental comparison of electromechanical properties and efficiency of HTS and ferromagnetic hysteresis motors  

Microsoft Academic Search

Hysteresis motors are very attractive in a wide range of fractional power applications, due to its torque-speed characteristics and simplicity of construction. This motor's performance is expected to improve when HTS rotors are used, and in fact, hysteresis motors have shown to be probably the most viable electrical machines using HTS materials. While these motors, either conventional or HTS, are

D Inácio; S Inácio; J Pina; A Gonçalves; M Ventim Neves; A Leão Rodrigues

2008-01-01

361

Reinforcement Learning for Characterization of Hysteresis Behavior in Shape Memory Alloys, and Application to  

E-print Network

Reinforcement Learning for Characterization of Hysteresis Behavior in Shape Memory Alloys � Electric propulsion, advanced fuel cells, high- efficiency electric motors � Integrated advanced control�Strain Relationship: HYSTERESIS Behavior based on a 2-D FIELD, not a 2-D PATH #12;Kirkpatrick & Valasek - 6 CURRENT

Valasek, John

362

Analysis of a Hysteresis Motor on Asynchronous Speed Using Complex Permeability  

Microsoft Academic Search

This paper deals with a method for determining the complex permeability in analysis of hysteresis motors. The method assumes that the magnetic intensity distribution is sinusoidal in the direction of rotation. Analysis of the asynchronous speed of a hysteresis motor is then performed for cylindrical coordinates, using modified Bessel functions. The results of calculations are in good agreement with experimental

T. Horii; N. Yuge; G. Wakui

1994-01-01

363

Decentralized adaptive stabilization in the presence of unknown backlash-like hysteresis  

Microsoft Academic Search

Due to the difficulty of handling both hysteresis and interactions between subsystems, there is still no result available on decentralized stabilization of unknown interconnected systems with hysteresis, even though the problem is practical and important. In this paper, we provide solutions to this challenging problem by proposing two new schemes to design decentralized output feedback adaptive controllers using backstepping approach.

Changyun Wen; Jing Zhou

2007-01-01

364

Devised loop-in-loop technique in mitral valve repair.  

PubMed

The loop technique is useful for multiple chordal reconstructions in mitral valve repair. Although it is easy to anchor the loop to the tip of the prolapsed leaflet, take-down of the anchored loop is not easy. The devised loop-in-loop technique makes intraoperative adjustment of the neochordae quick and easy. This article describes a straightforward and reproducible method for secure anchoring and, if necessary, take-down of neochordae using the loop-in-loop technique for mitral valve repair. PMID:24887864

Tokunaga, Shigehiko; Yasuda, Shota; Masuda, Munetaka

2014-11-01

365

Connecting PHP and PHP Loops  

E-print Network

Connecting PHP and MySQL 1 #12;Outline · PHP Loops · PHPMyAdmin · Introducing SQL · Connecting Database from PHP · Exercises 2 #12;Loops · A loop statement is a control structure that repeatedly PHP supports the C style while loop ­ The body of the cycle

Graham, Nick

366

Shape of cosmic string loops  

NASA Astrophysics Data System (ADS)

Complicated cosmic string loops will fragment until they reach simple, nonintersecting (“stable”) configurations. Through extensive numerical study we characterize these attractor loop shapes including their length, velocity, kink, and cusp distributions. We find that an initial loop containing M harmonic modes will, on average, split into 3M stable loops. These stable loops are approximately described by the degenerate kinky loop, which is planar and rectangular, independently of the number of modes on the initial loop. This is confirmed by an analytic construction of a stable family of perturbed degenerate kinky loops. The average stable loop is also found to have a 40% chance of containing a cusp. We examine the properties of stable loops of different lengths and find only slight variation. Finally we develop a new analytic scheme to explicitly solve the string constraint equations.

Copi, Craig J.; Vachaspati, Tanmay

2011-01-01

367

Diamagnetic loop for KSTAR.  

NASA Astrophysics Data System (ADS)

Three sets of diamagnetic loop (DL), at different locations, are designed to measure diamagnetic flux during a plasma discharge in the KSTAR machine. Each set consists of two concentric poloidal loops, and it is used for the diamagnetic flux measurement with the compensation of a ripple from to the power supply producing a toroidal field and a pick-up signal from the poloidal field due to the misalignment in the installation. One set is installed on inner wall of the vacuum vessel for the flux measurement at the first plasma in the KSTAR machine. It is located at a toroidal angle in the vacuum vessel, and the gap distance between inner and outer loops is 2 cm. An accurate position measurement of the two loops is done by using a laser tracker system after the installation. The in-situ calibration of the loops is done from the toroidal flux measurement. In the measurement, the electric current of less than 100A is applied to the toroidal field coils. In this work, present status of the DL for the initial measurement in the KSTAR machine will be presented.

Bak, Jun-Gyo; Lee, Sang-Gon; Ka, Eun-Mie

2007-11-01

368

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

369

Overview of Loop Heat Pipe Operation  

NASA Technical Reports Server (NTRS)

Loop heat pipes (LHP's) are two-phase heat transfer devices that utilize the evaporation and condensation of a working fluid to transfer heat, and the capillary forces developed in the porous wicks to circulate the fluid. The LHP was first developed in the former Soviet Union in the early 1980s, about the same time that the capillary pumped loop (CPL) was developed in the United States. The LHP is known for its high pumping capability and robust operation mainly due to the use of fine-pored metal wicks and an integral evaporator/hydro-accumulator design. The LHP technology is rapidly gaining acceptance in aerospace community. It is the baseline design for thermal control of several spacecraft, including NASA's GLAS and Chemistry, ESA's ATLID, CNES' STENTOR, RKA's OBZOR, and several commercial satellites. Numerous LHP papers have been published since the mid-1980's. Most papers presented test results and discussions on certain specific aspects of the LHP operation. LHP's and CPL's show many similarities in their operating principles and performance characteristics. However, they also display significant differences in many aspects of their operation. Some of the LHP behaviors may seem strange or mysterious, even to experienced CPL practitioners. The main purpose of this paper is to present a systematic description of the operating principles and thermal-hydraulic behaviors of LHP'S. LHP operating principles will be given first, followed by a description of the thermal-hydraulics involved in LHP operation. Operating characteristics and important parameters affecting the LHP operation will then be described in detail. Peculiar behaviors of the LHP, including temperature hysteresis and temperature overshoot during start-up, will be explained. For simplicity, most discussions will focus upon LHP's with a single evaporator and a single condenser, but devices with multiple evaporators and condensers will also be discussed. Similarities and differences between LHP's and CPL's will be addressed throughout the paper whenever appropriate.

Ku, Jentung

1999-01-01

370

Quark loop calculations  

NASA Astrophysics Data System (ADS)

Quark loop effects are studied with the stochastic matrix inversion algorithm. Z2 microcanonical noise is introduced to study the deviation from the orthonormality condition for finite configurations and compare with other noises. The results of the quark loops for various currents on a 16 3 × 24 lattice at ? = 6.0 with Wilson fermion ( ? = .148) are obtained for the Z2microcanonical noise. The results on the quark condensate, the topological susceptibility are given. We also discuss the feasibility for the two-point and three-point function calculations.

Dong, Shao-Jing; Liu, Keh-Fei

371

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

372

Temperature-dependent gate-swing hysteresis of pentacene thin film transistors  

NASA Astrophysics Data System (ADS)

The temperature-dependent hysteresis-type transfer characteristics of pentacene-based organic thin film transistors (OTFTs) were researched. The temperature-dependent transfer characteristics exhibit hopping conduction behavior. The fitting data for the temperature-dependent off-to-on and on-to-off transfer characteristics of OTFTs demonstrate that the hopping distance (ah) and the barrier height for hopping (q?t) control the carrier flow, resulting in the hysteresis-type transfer characteristics of OTFTs. The hopping model gives an explanation of the gate-swing hysteresis and the roles played by q?t and ah.

Lin, Yow-Jon; Lin, Yu-Cheng

2014-10-01

373

Implications of NiMH Hysteresis on HEV Battery Testing and Performance  

SciTech Connect

Nickel Metal-Hydride (NiMH) is an advanced high-power battery technology that is presently employed in Hybrid Electric Vehicles (HEVs) and is one of several technologies undergoing continuing research and development by FreedomCAR. Unlike some other HEV battery technologies, NiMH exhibits a strong hysteresis effect upon charge and discharge. This hysteresis has a profound impact on the ability to monitor state-of-charge and battery performance. Researchers at the Idaho National Engineering and Environmental Laboratory (INEEL) have been investigating the implications of NiMH hysteresis on HEV battery testing and performance. Experimental results, insights, and recommendations are presented.

Motloch, Chester George; Belt, Jeffrey R; Hunt, Gary Lynn; Ashton, Clair Kirkendall; Murphy, Timothy Collins; Miller, Ted J.; Coates, Calvin; Tataria, H. S.; Lucas, Glenn E.; Duong, T.Q.; Barnes, J.A.; Sutula, Raymond

2002-08-01

374

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); Avraham E. Mayo (The Weizman Institute of Science;Departments of Molecular Cell Biology and Physics of Complex Systems REV)

2004-05-11

375

Thermodynamic Model for Contact Angle Hysteresis on Rough Surfaces  

NASA Astrophysics Data System (ADS)

Wettability of solid surfaces can be tuned by introducing roughness. This effect has been explained by Wenzel, whereby texturing increases the degree of hydrophilicity (hydrophobicity) of an intrinsic hydrophilic (hydrophobic) flat surface. However, experimentally observed dynamic contact angles deviate significantly from those predicted by Wenzel equation. In this work, we demonstrate that local contact line distortion and pinning on structured surfaces is the key aspect that needs to be accounted for in the dynamic droplet models. Contact line distortions and pinning were visualized and analyzed to develop a thermodynamic model for contact angle hysteresis on rough surfaces. The developed model showed good agreement with the experimental advancing and receding contact angles, both at low and high solid fractions. The thermodynamic model was further extended to demonstrate its capability to capture droplet shape evolution during liquid addition and removal in our experiments and those in literature. The understanding developed in this study offers new insight extending the fundamental understanding of solid-liquid interactions required for the design of advanced functional coatings for microfluidics, biological, manufacturing, and heat transfer applications.

Raj, Rishi; Enright, Ryan; Adera, Solomon; Wang, Evelyn

2013-03-01

376

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

377

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

378

In the Loop  

ERIC Educational Resources Information Center

In the mid-1800s, Englishman John Venn invented a type of diagram to help visualize logical relationships. A Venn diagram is simply a rectangular box with circular loops in it that overlap to show how objects are related. This article describes activities with Venn diagrams that can be a fun way to sharpen students' logic skills and develop number…

Naylor, Michael

2006-01-01

379

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

380

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

381

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

382

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.

383

Automatic loop interchange  

Microsoft Academic Search

Parallel and vector machines are becoming increasingly important to many computation intensive applications. Effectively utilizing such architectures, particularly from sequential languages such as Fortran, has demanded increasingly sophisticated compilers. In general, a compiler needs to significantly reorder a program in order to generate code optimal for a specific architecture.Because DO loops typically control the execution of a number of statements,

John R. Allen; Ken Kennedy

1984-01-01

384

COLD TEST LOOP INTEGRATED TEST LOOP RESULTS  

SciTech Connect

A testing facility (Cold Test Loop) was constructed and operated to demonstrate the efficacy of the Accelerated Waste Retrieval (AWR) Project's planned sluicing approach to the remediation of Silos 1 and 2 at the Fernald Environmental Management Project near Cincinnati, Ohio. The two silos contain almost 10,000 tons of radium-bearing low-level waste, which consists primarily of solids of raffinates from processing performed on ores from the Democratic Republic of Congo (commonly referred to as ''Belgium Congo ores'') for the recovery of uranium. These silos are 80 ft in diameter, 36 ft high to the center of the dome, and 26.75 ft to the top of the vertical side walls. The test facility contained two test systems, each designed for a specific purpose. The first system, the Integrated Test Loop (ITL), a near-full-scale plant including the actual equipment to be installed at the Fernald Site, was designed to demonstrate the sluicing operation and confirm the selection of a slurry pump, the optimal sluicing nozzle operation, and the preliminary design material balance. The second system, the Component Test Loop (CTL), was designed to evaluate many of the key individual components of the waste retrieval system over an extended run. The major results of the initial testing performed during July and August 2002 confirmed that the AWR approach to sluicing was feasible. The ITL testing confirmed the following: (1) The selected slurry pump (Hazleton 3-20 type SHW) performed well and is suitable for AWR application. However, the pump's motor should be upgraded to a 200-hp model and be driven by a 150-hp variable-frequency drive (VFD). A 200-hp VFD is not much more expensive and would allow the pump to operate at full speed. (2) The best nozzle performance was achieved by using 15/16-in. nozzles operated alternately. This configuration appeared to most effectively mine the surrogate. (3) The Solartron densitometer, which was tested as an alternative mass flow measurement device, did not operate effectively. Consequently, it is not suitable for application to the AWR process. (4) Initially, the spray ring (operated at approximately 2300 psi) and the nozzles provided by the pump vendor did not perform acceptably. The nozzles were replaced with a more robust model, and the performance was then acceptable. (5) The average solids concentration achieved in the slurry before Bentogrout addition was approximately 16% by weight. The solids concentration of the slurry after Bentogrout addition ranged from 26% to approximately 40%. The slurry pump and ITL system performed well at every concentration. No line plugging or other problems were noted. The results of the CTL runs and later ITL testing are summarized in an appendix to this report.

Abraham, TJ

2003-10-22

385

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.

386

Pulsed I –V measurement method to obtain hysteresis-free characteristics of graphene FETs  

NASA Astrophysics Data System (ADS)

Current-voltage (I–V) characteristics of the graphene field effect transistors (GFETs) are measured by the dc, fast I–V (FIV), and pulsed I–V (PIV) methods and analyzed. The hysteresis and conductance in the dc measurement are affected by the sweeping bias range and direction. The I–V curves measured by the FIV method show reduced hysteresis and enhanced conductance at a faster sweeping rate, but are still affected by the sweeping bias range. By applying the PIV method, the hysteresis can be suppressed significantly while the conductance is improved by controlling turn-on, turn-off times (t on and t off) and the gate bias during t off (V base) regardless of the sweeping bias range. With short t on, long t off, and V base of 0 V, the hysteresis-free characteristics of GFETs are obtained.

Park, Jun-Mo; Lee, Dongho; Shim, Jeoyoung; Jeon, Taehan; Eom, Kunsun; Park, Byung-Gook; Lee, Jong-Ho

2014-09-01

387

Two-Dimensional Computational Fluid Dynamics Analysis of Hysteresis around Supersonic Biplane in Supersonic Flow  

NASA Astrophysics Data System (ADS)

The Busemann biplane is well known as the airfoil that has zero wave drag at the supersonic flight in the linear theory. It is found that this airfoil has a hysteresis in drag values from the transonic speeds through the low supersonic speeds based on Computational Fluid Dynamics (CFD) analysis. This paper shows that this hysteresis is explained by the Kantrowitz-Donaldson Criteria that usually defines the start and unstart of the supersonic intake.

Yonezawa, Masahito; Yamashita, Hiroshi; Obayashi, Shigeru; Kusunose, Kazuhiro

388

Numerical modeling of two-phase hysteresis combined with an interface condition for heterogeneous porous media  

Microsoft Academic Search

This paper presents a numerical implementation of two-phase capillary hysteresis and its combination with a capillary interface\\u000a condition for the treatment of heterogeneities. The hysteresis concepts chosen in this work are first implemented in a node-centered\\u000a FV discretization scheme and subsequently combined with the interface condition that predicts sharp saturation discontinuities\\u000a at material interfaces, based on a pressure equilibrium concept.

Alexandros Papafotiou; Hussam Sheta; Rainer Helmig

2010-01-01

389

Influence of mounting on the hysteresis of polymer fiber Bragg grating strain sensors.  

PubMed

Fiber Bragg grating sensors recorded in poly(methyl methacrylate) fiber often exhibit hysteresis in the response of Bragg wavelength to strain, particularly when exposed to high levels of strain. We show that, when such a fiber grating sensor is bonded directly to a substrate, the hysteresis is reduced by more than 12 times, compared to the case where the sensor is suspended freely between two supports. PMID:23632489

Abang, Ada; Webb, David J

2013-05-01

390

Ion-dosage-dependent room-temperature hysteresis in MOS structures with thin oxides  

Microsoft Academic Search

Two sets of metal-oxide-silicon (MOS) structures with oxide thicknesses of 115 and 350 Å, respectively, were exposed to 16-keV Si ion beams after dry oxidation. Small-signal capacitance-voltage measurements at room temperature revealed a hysteresis effect in the ion exposed samples, whose magnitude and direction depended on the ion dosage. No hysteresis could be detected in the control (unimplanted) samples. Mobile

Arya Raychaudhuri; S. Chatterjee; S. Ashok; S. Kar

1991-01-01

391

Neural modeling of rate-dependent and asymmetric hysteresis in ultrasonic motors  

Microsoft Academic Search

Usually, rotary travelling wave ultrasonic motor (RTWUSM) is involved with complex characteristic such as non-symmetric and rate-dependent hysteresis due to the inverse piezoelectric effect in the stator and the dynamics containing in the rotor. It is known that the hysteresis existing in RTWUSM is also a non-smooth nonlinearity with multi-valued mapping. Thus, the modeling of such characteristic of the RTWUSM

Xinliang Zhang; Yonghong Tan; Chun-Yi Su; Binyi Wu

2009-01-01

392

Fuzzy control design of a magnetically actuated optical image stabilizer with hysteresis compensation  

NASA Astrophysics Data System (ADS)

A fuzzy controller (FC) is designed for a magnetically actuated optical image stabilizer (OIS) in order to suppress the vibrations caused by hand shakings and hysteresis. To this end, the dynamic model of the OIS with consideration of hysteresis is first established, along with assuming the hand-shaking vibration as sinusoidal excitations. It is clearly shown that with capability of continuing parameter tuning, the FC is superior to the conventional PID for vibration suppression.

Tu, Tse-Yi; Chao, Paul C.-P.; Chiu, Chi-Wei; Wang, Chun-Chieh; Huang, Jeng-Shen

2009-04-01

393

Improved performance of polyphase hysteresis-reluctance motors fed from single-phase supplies  

Microsoft Academic Search

The balanced operation of a three-phase hysteresis-reluctance motor connected to a single-phase power supply was studied for both steady-state and dynamics modes of operation, and experimental tests were run to verify the analysis. Improved performance characteristics for balanced operation of a three-phase hysteresis-reluctance motor operated on a one-phase power supply are presented and optimum values of two-element balancers are shown

M. A. Rahman; A. M. Osheiba

1990-01-01

394

High-Efficiency operation of PWM inverter-driven hysteresis motor with short-duration overexcitation  

Microsoft Academic Search

This paper presents the new scheme for high-efficiency operation of PWM inverter-driven hysteresis motor with short-duration overexcitation. When the terminal voltage Vi of the hysteresis motor running at synchronous speed is continuously increased up to nVi (n>1) and then continuously decreased to Vi, input currents are reduced and output power is increased at the same time. Because of this, the

Tomotsugu Kubota; Takahiro Tamura; Kazumi Kurihara

2009-01-01

395

Analysis of field oriented control for permanent magnet hysteresis synchronous motors  

Microsoft Academic Search

A microprocessor implementation of the field-oriented control scheme for the permanent magnet (PM) hysteresis synchronous motor is reported. The basic principle is to decouple the torque-current component from the flux-current component so that these two components can be independently controlled. A d-q axis model of the PM hysteresis synchronous motor is presented, and the field-oriented control obtained from the basic

Jianhua Qian; M. Azizur Rahman

1993-01-01

396

Modeling a Hot Wheels Loop  

NSDL National Science Digital Library

In this activity a Tracker model is compared with a toy truck attempting to drive up and around a Hot Wheels vertical loop track. Three different videos show the truck entering the loop at different speeds. For related EJS models see Particle Motion On A Curve and Particle Motion On A Vertical Elliptical Loop. The zip file includes all three videos and pdf instructions.

Brown, Douglas

2012-01-31

397

Phase-coexistence and thermal hysteresis in samples comprising adventitiously doped MnAs nanocrystals: programming of aggregate properties in magnetostructural nanomaterials.  

PubMed

Small changes in the synthesis of MnAs nanoparticles lead to materials with distinct behavior. Samples prepared by slow heating to 523 K (type-A) exhibit the characteristic magnetostructural transition from the ferromagnetic hexagonal (?) to the paramagnetic orthorhombic (?) phase of bulk MnAs at Tp = 312 K, whereas those prepared by rapid nucleation at 603 K (type-B) adopt the ? structure at room temperature and exhibit anomalous magnetic properties. The behavior of type-B nanoparticles is due to P-incorporation (up to 3%), attributed to reaction of the solvent (trioctylphosphine oxide). P-incorporation results in a decrease in the unit cell volume (?1%) and shifts Tp below room temperature. Temperature-dependent X-ray diffraction reveals a large region of phase-coexistence, up to 90 K, which may reflect small differences in Tp from particle-to-particle within the nearly monodisperse sample. The large coexistence range coupled to the thermal hysteresis results in process-dependent phase mixtures. As-prepared type-B samples exhibiting the ? structure at room temperature convert to a mixture of ? and ? after the sample has been cooled to 77 K and rewarmed to room temperature. This change is reflected in the magnetic response, which shows an increased moment and a shift in the temperature hysteresis loop after cooling. The proportion of ? present at room temperature can also be augmented by application of an external magnetic field. Both doped (type-B) and undoped (type-A) MnAs nanoparticles show significant thermal hysteresis narrowing relative to their bulk phases, suggesting that formation of nanoparticles may be an effective method to reduce thermal losses in magnetic refrigeration applications. PMID:24893115

Zhang, Yanhua; Regmi, Rajesh; Liu, Yi; Lawes, Gavin; Brock, Stephanie L

2014-07-22

398

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

399

The FALC-Loop web server for protein loop modeling  

PubMed Central

The FALC-Loop web server provides an online interface for protein loop modeling by employing an ab initio loop modeling method called FALC (fragment assembly and analytical loop closure). The server may be used to construct loop regions in homology modeling, to refine unreliable loop regions in experimental structures or to model segments of designed sequences. The FALC method is computationally less expensive than typical ab initio methods because the conformational search space is effectively reduced by the use of fragments derived from a structure database. The analytical loop closure algorithm allows efficient search for loop conformations that fit into the protein framework starting from the fragment-assembled structures. The FALC method shows prediction accuracy comparable to other state-of-the-art loop modeling methods. Top-ranked model structures can be visualized on the web server, and an ensemble of loop structures can be downloaded for further analysis. The web server can be freely accessed at http://falc-loop.seoklab.org/. PMID:21576220

Ko, Junsu; Lee, Dongseon; Park, Hahnbeom; Coutsias, Evangelos A.; Lee, Julian; Seok, Chaok

2011-01-01

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

DrillfieldDr. P E R R Y S T R E E T  

E-print Network

Burruss Hall Admissions Academic Buildings Burruss Hall Student Center Derring Hall New Virginia TechAlumniMall DrillfieldDr. P E R R Y S T R E E T DerringHall Pamplin Hall Norris HallHoldenHall Hancock Hall WhittemoreHall Bishop- Favrao Hall BurrussHall Randolph Hall Cowgill Hall Chemistry Physics

Buehrer, R. Michael

402

Micro-Cantilever Anemometer for Cryogenic Helium J. Salort, A. Monfardini and P.-E. Roche  

E-print Network

Micro-Cantilever Anemometer for Cryogenic Helium J. Salort, A. Monfardini and P.-E. Roche Institut anemometer for liquid helium, based on a micro-cantilever. Our aim was to design a probe significatively anemometer in superfluid helium Below 2.17 K, liquid helium undergoes a phase transition: the new phase

Boyer, Edmond

403

A p p e n d i x E Promotion Kit  

E-print Network

E­1 A p p e n d i x E Promotion Kit Getting Noticed Your involvement in the Media-Smart Youth: Eat messages about youth media, nutrition, and physical activity behaviors that you can customize-Smart Youth program A Media-Smart Youth fact sheet that you can reproduce and distribute as part of your

Rau, Don C.

404

A p p e n d i x C Additional Snack  

E-print Network

C­1 A p p e n d i x C Additional Snack Break Options Easy-To-Prepare Healthy Snacks CSweet Snacks Crunchy Snacks Sesame breadsticks Sunflower seeds Pumpkin seeds Whole-grain bagel chips Baked potato (soy beans) Zucchini #12;C­3 One or More Steps to Easy and Healthy Snacks Chip/Dip Snacks Low

Rau, Don C.

405

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 that the University of Nevada Las Vegas Graduate Program in Medical Physics has been granted reaccreditation through

Hemmers, Oliver

406

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.

Sullivan, Megan

2005-07-01

407

Statement of Tim Lomax, Ph.D., P.E. Senior Research Engineer and Regents Fellow  

E-print Network

1 Statement of Tim Lomax, Ph.D., P.E. Senior Research Engineer and Regents Fellow Texas assurance that: 1. Projects will have the greatest impact considering factors including congestion, economic delivered the following major products: · Early Recommendations Report identifying and recommending funding

408

Karen C. Chou Karen C. Chou, Ph.D., P.E.  

E-print Network

Page 1 Karen C. Chou Karen C. Chou, Ph.D., P.E. List of Publications PUBLICATIONS (Refereed Papers.F. and CHOU, K.C. (2004) "Partial Resistance Factor Design on Steel-Concrete Beam-Columns", Engineering.G., and GOODPASTURE, D.W. (2001) "Productivity of Highway Construction Operations", TRB 80th Annual Meeting, January

Ottino, Julio M.

409

Nematode (Roundworm) Infections in Fish1 Roy P. E. Yanong2  

E-print Network

Cir 91 Nematode (Roundworm) Infections in Fish1 Roy P. E. Yanong2 1. This document is Circular 91 Dean Introduction Nematodes, or roundworms, infect many different species of aquacultured and wild fish. Small numbers of nematodes often occur in healthy fish, but high numbers cause illness or even death

Watson, Craig A.

410

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 research, educational information and other services only to individuals and institutions that function/IFAS Extension. Introduction Hydrogen peroxide is commonly used as a disinfectant for cleaning wounds in people

Watson, Craig A.

411

Rossby Wave Instability and Apparent Phase Speeds in Large Ocean Basins P. E. ISACHSEN  

E-print Network

Rossby Wave Instability and Apparent Phase Speeds in Large Ocean Basins P. E. ISACHSEN Department 30 November 2005, in final form 31 May 2006) ABSTRACT The stability of baroclinic Rossby waves theory in latitude bands. The evolution of large-scale waves was then simulated using the Regional Ocean

LaCasce, Joseph H.

412

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

E-print Network

management and water quality--are critical for maximizing aquatic animal health. However, all facilitiesFA156 Use of Vaccines in Finfish Aquaculture1 Roy P. E. Yanong2 1. This document is FA156, one prevention that historically have been used in other animal industries are vaccines and immunostimulants

Watson, Craig A.

413

Dr. Miguel Vlez-Reyes, P.E. Electrical and Computer Engineering Department  

E-print Network

Dr. Miguel V�lez-Reyes, P.E. Professor Electrical and Computer Engineering Department University.S.E.E. University of Puerto Rico Mayag�ez Campus, June 1985 Appointments Department of Electrical and Computer Engineering, University of Puerto Rico Mayag�ez Campus, Mayag�ez, P.R. Professor July 2000-Present Associate

Gilbes, Fernando

414

Hazmat Accident Education -An Integrated Shirley E. Clark, Ph.D., P.E.  

E-print Network

Hazmat Accident Education - An Integrated Approach By Shirley E. Clark, Ph.D., P.E. Formerly Accident Education - An Integrated Approach 6. Performing Organization Code 7. Authors Shirley E. Clark, accidents, emergency planning, emergency response 18. Distribution Statement 19. Security Classification (of

Pitt, Robert E.

415

FLY ASH GENERATION AND UTILIZATION -AN OVERVIEW* Tarun R. Naik, Ph.D., P.E.  

E-print Network

FLY ASH GENERATION AND UTILIZATION - AN OVERVIEW* By Tarun R. Naik, Ph.D., P.E. Director, Center-6958 ______________________________________________________________________________ *For publication in the book titled "Recent Trend in Fly Ash Utilization", June 1993. #12;1 FLY ASH production and utilization of fly ash throughout the world. The utilization potential for fly ash generated

Wisconsin-Milwaukee, University of

416

3D Engineered Models for Highway Construction Gabe Nelson, P.E.  

E-print Network

3D Engineered Models for Highway Construction Gabe Nelson, P.E. Snyder & Associates, Inc. Overview of 3D Engineered Models for Highway Construction Module 1 Introduction #12;3D Engineered Models & Quality � Protect the Environment � Every Day Counts 2 included 3D Engineered Models for Construction

417

NEW MEASUREMENTS ON TIME DECREASE OF PERMEABILITY A. J. BOSMAN, P. E. BROMMER, G. W. RATHENAU,  

E-print Network

to the gas atmosphere. We assume that all alloys were saturated after 30 hours. The carbon contents relative241 NEW MEASUREMENTS ON TIME DECREASE OF PERMEABILITY A. J. BOSMAN, P. E. BROMMER, G. W. RATHENAU. On trouve que cet effet a peu d'influence. Il semble que le carbone soit plus efficace que l'azote pour

Paris-Sud XI, Université de

418

Shelley J. Row, P.E., PTOE Director, ITS Joint Program Office  

E-print Network

Shelley J. Row, P.E., PTOE Director, ITS Joint Program Office Research and Innovative Technology Administration U.S. Department of Transportation Shelley J. Row is Director of the U.S. Department since January 2007. As JPO Director, Ms. Row manages a $110 million annual budget to advance research

Minnesota, University of

419

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.

420

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

421

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

422

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

423

Potato Response to ACA on Several Soils K.A. Kelling and P.E. Speth  

E-print Network

Potato Response to ACA on Several Soils K.A. Kelling and P.E. Speth Department of Soil Science University of Wisconsin- Madison #12;ACA ­ Zinc Ammonium acetate ­ 15% N, 17% Zn ­ Recommended rate 0.33-0.67 pt/a ACA Plus ­ 7.5% N, 8.5 %Zn ­ More compatible with wide range of fertilizers ­ Double rate (0

Balser, Teri C.

424

Numerical and experimental comparison of electromechanical properties and efficiency of HTS and ferromagnetic hysteresis motors  

NASA Astrophysics Data System (ADS)

Hysteresis motors are very attractive in a wide range of fractional power applications, due to its torque-speed characteristics and simplicity of construction. This motor's performance is expected to improve when HTS rotors are used, and in fact, hysteresis motors have shown to be probably the most viable electrical machines using HTS materials. While these motors, either conventional or HTS, are both hysteresis motors, they base their operation on different physical phenomena: hysteretic behaviour in conventional ferromagnetic materials is due to the material's non-linear magnetic properties, while in HTS materials the hysteresis has an ohmic nature and is related with vortices' dynamics. In this paper, theoretical aspects of both conventional and HTS hysteresis motors are discussed, its operation principles are highlighted, and the characteristics of both motors are presented. The characteristics, obtained both by experimental tests and numerical simulation (made with commercial software), are compared, in order to evaluate not only the motor's electromechanical performances but also the overall systems efficiency, including cryogenics for the HTS device.

Inácio, D.; Inácio, S.; Pina, J.; Gonçalves, A.; Ventim Neves, M.; Leão Rodrigues, A.

2008-02-01

425

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

426

The double loop mattress suture.  

PubMed

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

427

Conditions necessary for capillary hysteresis in porous media: Tests of grain-size and surface tension influences  

SciTech Connect

Hysteresis in the relation between water saturation and matric potential is generally regarded as a basic aspect of unsaturated porous media. However, the nature of an upper length scale limit for saturation hysteresis has not been previously addressed. Since hysteresis depends on whether or not capillary rise occurs at the grain scale, this criterion was used to predict required combinations of grain size, surface tension, fluid-fluid density differences, and acceleration in monodisperse systems. The Haines number (Ha), composed of the aforementioned variables, is proposed as a dimensionless number useful for separating hysteretic (Ha < 15) versus nonhysteretic (Ha > 15) behavior. Vanishing of hysteresis was predicted to occur for grain sizes greater than 10.4 +- 0.5 mm, for water-air systems under the acceleration of ordinary gravity, based on Miller-Miller scaling and Haines' original model for hysteresis. Disappearance of hysteresis was tested through measurements of drainage and wetting curves of sands and gravels and occurs between grain sizes of 10 and 14 mm (standard conditions). The influence of surface tension was tested through measurements of moisture retention in 7 mm gravel, without and with a surfactant (sodium dodecylbenzenesulfonate (SDBS)). The ordinary water system (Ha = 7) exhibited hysteresis, while the SDBS system (Ha = 18) did not. The experiments completed in this study indicate that hysteresis in moisture retention relations has an upper limit at Ha = 16 +- 2 and show that hysteresis is not a fundamental feature of unsaturated porous media.

Tokunaga, Tetsu K.; Olson, Keith R.; Wan, Jiamin

2004-03-12

428

Self-Organization and hysteresis in a simple plasma model  

NASA Astrophysics Data System (ADS)

The study of self-organization (SO) and its relation with turbulence is a subject at the forefront of astrophysics and space research, and in particular, it may have relevance in the behavior of the magnetospheric environment. We will study the intermittent energy dissipation in a simple plasma models of a current sheet induced by a localized instability with a hysteretic dissipation loop. The multi-state behavior present in this model seems to occur naturally in complex systems, and is of particular relevance for the existence of a out-of-equilibrium globally stable state with underlying turbulent behavior. The complex behavior of this system will be studied using the techniques that are being developed for spatio-temporal chaotic dynamics. In the case of the magnetotail, this self-organized state [Chang 1998] is necessary to bridge the two seemingly contradicting observations. While the magnetotail plasma sheet appears to be a dynamic and turbulent region [Borovsky et al., 1997], the magnetotail activity seems to be predictable [Vassiliadis et al., 1995], repeatable and globally coherent [Baker et al., 1998] as characterized by its different phases.

Valdivia, J. A.; Gomberoff, L.

2003-12-01

429

Simulation study shows hysteresis effect on oil recovery during a cyclic steam process  

SciTech Connect

The cyclic steam stimulation of heavy oil reservoirs is often difficult to simulate, primarily because individual fluid mobilities change drastically from the injection portion of a cycle to the production portion. To improve simulation capabilities, 2 major approaches have been proposed: one based on hysteresis of relative permeability and capillary pressure, and the other on vertical fractures. The results of simulation studies using 2 different commercial steamflood models indicate that the hysteresis approach is the most suitable choice when a mobile water zone is present in the reservoir and when there is no evidence that a vertical fracture exists. This work reviews the underlying basis for hysteresis and temperature effects on relative permeability and capillary pressure and discusses simulation results obtained with a set of 3-phase functions in a cyclic steam stimulation of heavy oil reservoirs (9 to 11 API crude bitumen). 21 references.

Bang, H.W.

1984-02-27

430

Physiological thermoregulation in a crustacean? Heart rate hysteresis in the freshwater crayfish Cherax destructor.  

PubMed

Differential heart rates during heating and cooling (heart rate hysteresis) are an important thermoregulatory mechanism in ectothermic reptiles. We speculate that heart rate hysteresis has evolved alongside vascularisation, and to determine whether this phenomenon occurs in a lineage with vascularised circulatory systems that is phylogenetically distant from reptiles, we measured the response of heart rate to convective heat transfer in the Australian freshwater crayfish, Cherax destructor. Heart rate during convective heating (from 20 to 30 degrees C) was significantly faster than during cooling for any given body temperature. Heart rate declined rapidly immediately following the removal of the heat source, despite only negligible losses in body temperature. This heart rate 'hysteresis' is similar to the pattern reported in many reptiles and, by varying peripheral blood flow, it is presumed to confer thermoregulatory benefits particularly given the thermal sensitivity of many physiological rate functions in crustaceans. PMID:15313496

Goudkamp, Jacqueline E; Seebacher, Frank; Ahern, Mark; Franklin, Craig E

2004-07-01

431

Diminution of contact angle hysteresis under the influence of an oscillating force.  

PubMed

We suggest a simple quantitative model for the diminution of contact angle hysteresis under the influence of an oscillatory force invoked by thermal fluctuations, substrate vibrations, acoustic waves, or oscillating electric fields. Employing force balance rather than the usual description of contact angle hysteresis in terms of Gibbs energy, we highlight that a wetting system, such as a sessile drop or a bubble adhered to a solid substrate, appears at long times to be partially or fully independent of contact angle hysteresis and thus independent of static friction forces, as a result of contact line pinning. We verify this theory by studying several well-known experimental observations such as the approach of an arbitrary contact angle toward the Young contact angle and the apparent decrease (or increase) in an advancing (or a receding) contact angle under the influence of an external oscillating force. PMID:24856418

Manor, Ofer

2014-06-17

432

Hysteresis between coral reef calcification and the seawater aragonite saturation state  

NASA Astrophysics Data System (ADS)

predictions of how ocean acidification (OA) will affect coral reefs assume a linear functional relationship between the ambient seawater aragonite saturation state (?a) and net ecosystem calcification (NEC). We quantified NEC in a healthy coral reef lagoon in the Great Barrier Reef during different times of the day. Our observations revealed a diel hysteresis pattern in the NEC versus ?a relationship, with peak NEC rates occurring before the ?a peak and relatively steady nighttime NEC in spite of variable ?a. Net ecosystem production had stronger correlations with NEC than light, temperature, nutrients, pH, and ?a. The observed hysteresis may represent an overlooked challenge for predicting the effects of OA on coral reefs. If widespread, the hysteresis could prevent the use of a linear extrapolation to determine critical ?a threshold levels required to shift coral reefs from a net calcifying to a net dissolving state.

McMahon, Ashly; Santos, Isaac R.; Cyronak, Tyler; Eyre, Bradley D.

2013-09-01

433

A Model for Rate-Dependent Hysteresis in Piezoceramic Materials Operating at Low Frequencies  

NASA Technical Reports Server (NTRS)

This paper addresses the modeling of certain rate-dependent mechanisms which contribute to hysteresis inherent to piezoelectric materials operating at low frequencies. While quasistatic models are suitable for initial material characterization in some applications, the reduction in coercive field and polarization values which occur as frequencies increase must be accommodated to achieve the full capabilities of the materials. The model employed here quantifies the hysteresis in two steps. In the first, anhysteretic polarization switching is modeled through the application of Boltzmann principles to balance the electrostatic and thermal energy. Hysteresis is then incorporated through the quantification of energy required to translate and bend domain walls pinned at inclusions inherent to the materials. The performance of the model is illustrated through a fit to low frequency data (0.1 Hz - 1 Hz) from a PZT5A wafer.

Smith, Ralph C.; Ounaies, Zoubeida; Wieman, Robert

2001-01-01

434

Loop-the-Loop: Bringing Theory into Practice  

ERIC Educational Resources Information Center

During the Thai high-school physics teacher training programme, we used an aluminum loop-the-loop system built by the Institute for the Promotion of Teaching Science and Technology (IPST) to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. There were 27 high-school teachers from three provinces,…

Suwonjandee, N.; Asavapibhop, B.

2012-01-01

435

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.

2012-09-06

436

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

437

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

438

Dynamic PID loop control  

E-print Network

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; Theilacker, J; Soyars, W; Martinez, A; Bossert, R; DeGraff, B; Darve, C

2012-01-01

439

Electric field induced fluorescence hysteresis of single molecules in poly(methyl methacrylate)  

NASA Astrophysics Data System (ADS)

Single molecule (SM) chips could serve as the fundamental devices in quantum information processing. In this context, a chip with the non-polar SMs of squaraine-derived rotaxanes embedded in a polar poly(methyl methacrylate) matrix was realized and the SM fluorescence hysteresis induced by the electric field was observed at room temperature. Here, we presented a model considering both of the electron transfer and space charge relaxation processes to explain the fluorescence hysteresis effect, and the model-based simulations agreed reasonably well with the experimental results.

Zhou, Haitao; Qin, Chengbing; Chen, Ruiyun; Zhang, Guofeng; Xiao, Liantuan; Jia, Suotang

2014-10-01

440

Hysteresis effects in instantaneous frequency scaling of attenuation on 20 and 30 GHz satellite links  

NASA Technical Reports Server (NTRS)

It has been observed with 20/30 GHz satellite beacon measurements that the ratio of 30 GHz to 20 GHz attenuation changes during some fade events. This ratio displays a hysteresis effect. This effect can be explained by a change in the drop size distribution (DSD) during the event. However, it appears only above approximately 6-8 dB of attenuation at 20 GHz. Instantaneous frequency scaling of attenuation is being proposed as part of an algorithm for uplink power control (ULPC) and the dynamic range of such an algorithm must be appropriately limited to avoid the hysteresis.

Sweeney, D. G.; Pratt, T.; Bostian, C. W.

1992-01-01

441

Roy P. E. Yanong, VMD Tropical Aquaculture Laboratory FAS/SFRC/IFAS/University of Florida RECENT PUBLICATIONS  

E-print Network

of mycobacteria in recirculating aquaculture systems and mycobacterial disease in fish. Journal of Aquatic AnimalRoy P. E. Yanong, VMD Tropical Aquaculture Laboratory FAS/SFRC/IFAS/University of Florida RECENT.H. Kilgore, R.P.E. Yanong, S. Graves, L. MacLaughlin, and B. Causey. 2008. Chapter 41: Aquacultured coral

Hill, Jeffrey E.

442

RUNNING HEAD: teacher expectancy effects in P.E. The Influence of Teacher Expectations on Students Achievement in Physical Education  

E-print Network

RUNNING HEAD: teacher expectancy effects in P.E. The Influence of Teacher Expectations on Students 32, 5 (2002) 591-607" #12;Teacher expectancy effects in P.E. 2 2 ABSTRACT The main purpose of this study was to explore the relation between teacher expectations and student achievement in physical

Paris-Sud XI, Université de

443

Nesting Loops March 7, 2012  

E-print Network

games, and we tied 0 games. You won the tournament! You may write your own messages to the user in as well. 1 Example: Nested For Loops Save this code in a .py file, and try running it. What do you see does it effect the behavior of the code, and why? 3 Example: If statement in a for loop Save this code

Lega, Joceline

444

Loop-bed combustion apparatus  

DOEpatents

The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.

Shang, Jer-Yu (Fairfax, VA); Mei, Joseph S. (Morgantown, WV); Slagle, Frank D. (Kingwood, WV); Notestein, John E. (Morgantown, WV)

1984-01-01

445

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

446

On the factor set of code loops  

E-print Network

A Code loop on a binary linear code that is doubly even with a factor set is shown to be a central loop, conjugacy closed loop, Burn loop and extra loop. General forms of the identities that define the factor set of a code are deduced.

Temitope Gbolahan Jaiyeola

2008-06-05

447

PHYSICAL REVIEW E 86, 056104 (2012) Nonequilibrium hysteresis and Wien effect water dissociation at a bipolar membrane  

E-print Network

PHYSICAL REVIEW E 86, 056104 (2012) Nonequilibrium hysteresis and Wien effect water dissociation and to estimate the amplitude of the transient hysteresis and the water-dissociation current. DOI: 10.1103/Phys exceed 10 MV/cm such that water can be dissociated. The resulting proton and hydroxyl ions

Chang, Hsueh-Chia

448

Robust adaptive controller design for a class of nonlinear systems preceded by generalized Prandtl-Ishlinskii Hysteresis representation  

Microsoft Academic Search

It is a challenge to fuse the available hysteresis models with controller design techniques to mitigate the effect of hysteresis when preceding with systems. Though the conventional Prandtl-Ishlinskii model has been primarily fused with robust control methods in the literature, the fusion of a generalized Prandtl-Ishlinskii model is a further interesting topic worthy of pursuing because it offers certain advantages

Ying Feng; Henry Hong; Xinkai Chen; Chun-Yi Su

2008-01-01

449

Modeling loop entropy.  

PubMed

Proteins fold from a highly disordered state into a highly ordered one. Traditionally, the folding problem has been stated as one of predicting "the" tertiary structure from sequential information. However, new evidence suggests that the ensemble of unfolded forms may not be as disordered as once believed, and that the native form of many proteins may not be described by a single conformation, but rather an ensemble of its own. Quantifying the relative disorder in the folded and unfolded ensembles as an entropy difference may therefore shed light on the folding process. One issue that clouds discussions of "entropy" is that many different kinds of entropy can be defined: entropy associated with overall translational and rotational Brownian motion, configurational entropy, vibrational entropy, conformational entropy computed in internal or Cartesian coordinates (which can even be different from each other), conformational entropy computed on a lattice, each of the above with different solvation and solvent models, thermodynamic entropy measured experimentally, etc. The focus of this work is the conformational entropy of coil/loop regions in proteins. New mathematical modeling tools for the approximation of changes in conformational entropy during transition from unfolded to folded ensembles are introduced. In particular, models for computing lower and upper bounds on entropy for polymer models of polypeptide coils both with and without end constraints are presented. The methods reviewed here include kinematics (the mathematics of rigid-body motions), classical statistical mechanics, and information theory. PMID:21187223

Chirikjian, Gregory S

2011-01-01

450

Hysteresis and the earnings of immigrants in the United States labour market  

Microsoft Academic Search

The paper analyses the role of hysteresis in explaining the slow wage convergence between certain immigrant groups and native workers. Using the 1990 Integrated Public Use Microdata Samples (IPUMS), the analysis reveals that past earnings history in the country of origin has a relatively smaller effect on post-migration earnings when compared to past earnings history in the US. In addition,

Veronica Cabezas; Jason MacDonald

1999-01-01

451

Nonlinear acoustic waves in media with hysteresis and long-time relaxation.  

PubMed

It is known that the media with complex structures (e.g., rocks and ceramics) possess an anomalously strong elastic nonlinearity. Nonlinear acoustic effects are used in a number of important applications, such as seismic waves (earthquakes), non-destructive testing, and contact physics. Two specific features were registered, in most of the experiments: hysteresis in the stress-strain relation and longtime relaxation (slow time). Some physical models, mostly phenomenological, have been suggested to explain these phenomena. However, there are very few works considering the effect of medium hysteresis and relaxation on wave propagation and oscillations in resonators. This presentation is a review of both published and new results in this area. Among the problems discussed are: (1) A brief overview of experiments and models; (2) Analysis of wave propagation in simplified models of media with hysteresis as opposed to the nonlinear waves in media characterized by elastic constants of second and third order; (3) Theory of wave interaction in resonators with hysteresis; (4) Study of waves in media with slow time relaxation; (5) Some data from laboratory and field experiments; (6) Some unsolved issues and the relevant future work will be outlined in conclusion. PMID:25235680

Ostrovsky, Lev A

2014-04-01

452

Multilevel hysteresis controller of the novel seven-level packed U cells converter  

Microsoft Academic Search

In this paper, authors propose a six-band hysteresis vector controller based on the seven level packed U cells (PUC) converter to alleviate harmonics contents of stator voltages and currents of the induction machine. Active and passive filters rating can thus be significantly reduced resulting on a high energetic efficiency and a reduced installation cost. The PUC topology was first introduced

Y. Ounejjar; K. Al-Haddad

2010-01-01

453

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

454

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

E-print Network

for harvesting most of the soil water, which then flows within the plant vascular system up to the leaves whereOnset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water] Estimation of water uptake by plants and subsequent water stress are complicated by the need to resolve

Katul, Gabriel

455

3-D numerical simulation of contact angle hysteresis for microscale two phase flow  

E-print Network

and the surface forces acting at the channel boundaries. Within the framework of a numerical volume of fluid (VOF Elsevier Ltd. All rights reserved. Keywords: Contact angle hysteresis; Volume of fluid (VOF); Two changes, the VOF approach is found to be among the 0301-9322/$ - see front matter Ã? 2007 Elsevier Ltd. All

Hidrovo, Carlos H.

456

Density hysteresis of heavy water confined in a nanoporous silica matrix  

E-print Network

Density hysteresis of heavy water confined in a nanoporous silica matrix Yang Zhanga,b , Antonio (received for review January 5, 2011) A neutron scattering technique was developed to measure the density in the measured density profiles between warming and cooling scans above 1,000 bars. We inter- pret

Chen, Sow-Hsin

457

Scaling behavior of hysteresis in multilayer MoS2 field effect transistors  

NASA Astrophysics Data System (ADS)

Extrinsic hysteresis effects are often observed in MoS2 field effect devices due to adsorption of gas molecules on the surface of MoS2 channel. Scaling is a common method used in ferroics to quantitatively study the hysteresis. Here, the scaling behavior of hysteresis in multilayer MoS2 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 (Vbg,max). It is interesting to find that the transition voltage in the forward sweep (VFW) and in the backward sweep (VBW) shifted to the opposite directions of back-gate voltage (Vbg) with increasing Vbg,max. However, when decreasing Vbg,max, VFW shifted to positive and reversibly recovered, but VBW almost kept unchanged. The evolution of ?A?, ?V, VFW, and VBW with Vbg,max were discussed by the electrons transferring process between the adsorbate and MoS2 channel.

Li, Tao; Du, Gang; Zhang, Baoshun; Zeng, Zhongming

2014-09-01

458

Hysteresis of soil moisture spatial heterogeneity and the "homogenizing" effect of vegetation  

E-print Network

Hysteresis of soil moisture spatial heterogeneity and the "homogenizing" effect of vegetation 16 September 2010. [1] By partitioning mass and energy fluxes, soil moisture exerts a fundamental experiment, this study investigates aspects of soil moisture spatial and temporal variability in a zeroorder

Troch, Peter

459

Simulation study shows hysteresis effect on oil recovery during a cyclic steam process  

Microsoft Academic Search

The cyclic steam stimulation of heavy oil reservoirs is often difficult to simulate, primarily because individual fluid mobilities change drastically from the injection portion of a cycle to the production portion. To improve simulation capabilities, 2 major approaches have been proposed: one based on hysteresis of relative permeability and capillary pressure, and the other on vertical fractures. The results of

Bang

1984-01-01

460

Dynamic simulation of an electrostatic micropump with pull-in and hysteresis phenomena  

Microsoft Academic Search

After presenting the role of micropumps in medical applications and demonstrating that an electrostatic micropump would seem to be the most appropriate, the geometrical and electrical static characteristics of this pump are summarized. Classical dynamic simulations do not take into account the pull-in effect or the hysteresis phenomenon, both of which appear in electrostatic micropumps. The novel principle of dynamic

Olivier Français; Isabelle Dufour

1998-01-01

461

High-precision control of piezoelectric nanopositioning stages using hysteresis compensator and disturbance observer  

NASA Astrophysics Data System (ADS)

This paper proposes a novel high-performance control scheme with hysteresis compensator and disturbance observer for high-precision motion control of a nanopositioning stage driven by a piezoelectric stack actuator (PSA). In the developed control scheme, a real-time inverse hysteresis compensator (IHC) with the modified Prandtl-Ishlinskii model is firstly designed to compensate for the asymmetric hysteresis nonlinearity of the PSA. Due to the imperfect compensation, the dynamics behaviors of the PSA-actuated stage with the IHC can be treated as a linear dynamic system plus a lumped disturbance term. Owing to the unknown nature of this lumped disturbance term, a disturbance observer (DOB) is used as a means for disturbance rejection. With the DOB, a tracking controller is finally designed and implemented to stabilize the position error. To verify the proposed control scheme, a real-time experimental platform with a PSA-actuated nanopositioning stage is built, and extensive experimental tests are performed. The comparative experimental results demonstrate the effectiveness and improved performance of the developed control approach in terms of the maximum-value errors, root-mean-square-value errors and hysteresis compensation.

Gu, Guo-Ying; Zhu, Li-Min; Su, Chun-Yi

2014-10-01

462

Hysteresis in corticospinal excitability during gradual muscle contraction and relaxation in humans  

Microsoft Academic Search

Many studies have demonstrated that the firing behavior of single motor units varies in a nonlinear manner to the exerted torque during gradual muscle contraction and relaxation. However, it is unclear whether corticospinal excitability has such a hysteresis-like feature. In this study, we examined corticospinal excitability using transcranial magnetic stimulation (TMS) during gradual muscle contraction and relaxation for torque regulation

Toshitaka Kimura; Kentaro Yamanaka; Daichi Nozaki; Kimitaka Nakazawa; Tasuku Miyoshi; Masami Akai; Tatsuyuki Ohtsuki

2003-01-01

463

Hybrid genetic algorithms for parameter identification of a hysteresis model of magnetostrictive actuators  

Microsoft Academic Search

In this paper, we present an improved hysteresis model for magnetostrictive actuators. To obtain optimal parameters of the model, we study two distinct hybrid strategies: namely, employing a gradient algorithm as a local search operation of a genetic algorithm (GA), and taking the best individual of a GA as the initial value of a gradient algorithm. Here, two different gradient

Jiaju Zheng; Shuying Cao; Hongli Wang; Wenmei Huang

2007-01-01

464

Direct measurement of the thermal hysteresis of antifreeze proteins (AFPs) using sonocrystallization.  

PubMed

Antifreeze proteins (AFPs) are of great importance for applications in cryomedicine or the food industry. They are frequently used to lower the freezing point by preventing the growth of larger ice crystals; thus, it is paramount to determine their thermal hysteretic characteristics. However, the experimental analysis of the thermal hysteresis-an effect that is characteristic for AFPs-remains a challenging process. An easy-to-use test method for measuring the thermal hysteresis of AFPs was developed and tested with the type III AFPs. Traditional methods that have been used until now have their disadvantages and limitations. The new measurement method described in this paper allows detection of the complete cooling, freezing, heating, and melting process in a single measurement. This makes it possible to directly determine the thermal hysteresis as a functional effect of the antifreeze proteins. Measurements of the thermal hysteresis were performed by applying ultrasound to initiate the crystallization process of the antifreeze protein solution. This ultrasound technique also allows a crystallization process to be performed at defined temperature. The demonstrated results were highly reproducible and could be clearly read off the measurement curves. As a future perspective, this enables the design of automatic test devices that can be also miniaturized. PMID:23121544

Gaede-Koehler, Andrea; Kreider, Alexej; Canfield, Peter; Kleemeier, Malte; Grunwald, Ingo

2012-12-01

465

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

466

perature sensitive. Both electrode pairs show approximately the same thermal hysteresis.  

E-print Network

. A. In "Ion-Selective Electrodes in Analytical Chemistry"; Freiser, H., Ed.; Plenum: New York, 1978 n "Ion-Seiectlve Electrodes"; Durst, R. A,, Ed.; National Bureauof Standards: Washington, DC, NBS236 perature sensitive. Both electrode pairs show approximately the same thermal hysteresis. The E

Mandelis, Andreas

467

Modeling of a three-layer piezoelectric bimorph beam with hysteresis  

Microsoft Academic Search

Piezoelectric actuators are usually stacked or bimorph in configuration. In this paper the mechanics of a three-layer piezoelectric bimorph is discussed and its dynamic model with hysteresis is presented. The results can be used to analyze piezoelectric actuators constructed with three-layer piezoelectric bimorphs. A piezoelectric bimorph actuator has been fabricated and experiments have been carried out to verify the model.

T. S. Low; W. Guo

1995-01-01

468

A hysteresis-free polymer-stabilised blue-phase liquid crystal , Daming Xua  

E-print Network

). Two UV wavelengths were used in our studies: = 365 nm (mercury lamp) and = 385 nm (UV LED hysteresis and good stability. Long ultraviolet (UV) wavelength and top-side (no IPS electrode) exposure is also investigated. Although a BPLC precursor without photoinitiator requires a higher UV dosage

Wu, Shin-Tson

469

A Domain Wall Model for Ferroelectric Hysteresis Ralph C. Smith 1 and Craig L. Hom 2  

E-print Network

A Domain Wall Model for Ferroelectric Hysteresis Ralph C. Smith 1 and Craig L. Hom 2 1 Center on the quantification of energy required to bend and translate domain walls and is developed in two steps. In the first the consideration of domain wall motion and the quantification of energy losses due to inherent inclusions

470

Construction and Experimental Implementation of a Model-Based Inverse Filter to Attenuate Hysteresis  

E-print Network

including Preisach models [7,18], domain wall mod- els [25, 26], micromechanical models [4, 10, 11 Hysteresis in Ferroelectric Transducers Andrew G. Hatch and Ralph C. Smith Tathagata De and Murti V. Salapaka nonlinearities are inherent properties of ferroelectric transducer ma- terials due to the noncentrosymmetric

471

Pentacobalt(II) cluster based pcu network exhibits both magnetic slow-relaxation and hysteresis behaviour.  

PubMed

A pentacobalt(II) cluster based 3D pcu network, [Co(5)(?(3)-OH)(2)(bpdc)(4)(dabco)(H(2)O)(2)] (bpdc = benzophenone-2,4'-dicarboxylate and dabco = 1,4-diazabicyclo[2,2,2] octane), exhibiting both slow magnetic relaxation and hysteresis behavior, has been hydrothermally synthesized. PMID:21069241

Hu, Sheng; Liu, Jun-Liang; Meng, Zhao-Sha; Zheng, Yan-Zhen; Lan, Yanhua; Powell, Annie K; Tong, Ming-Liang

2011-01-01

472

Magnetically hard materials for the motors of synchronous hysteresis electric motors  

Microsoft Academic Search

Synchronous hysteresis electric motors are widely used in automatic systems, high-speed mechanisms, and gyroscope drives in high-precision systems. The stator of such motors is the same as that of a synchronous or asynchronous electric motor, whereas the rotor is a hollow cylinder of magnetically hard alloy, mounted on a nonmagnetic bush. The cylinder may be monolithic or may consist of

E. V. Artamonov; M. A. Libman; N. N. Rudanovskii

2007-01-01

473

Analysis of field oriented control for permanent magnet hysteresis synchronous motors  

Microsoft Academic Search

Field oriented control schemes provide significant improvement to the dynamic performance of ac motors. A microprocessor implementation of the field oriented control scheme for the permanent magnet hysteresis synchronous motor has been reported for the first time. The basic principle is to decouple the torque-current component from the flux-current component so that these two components can be independently controlled. A

J. Qian; M. A. Rahman

2009-01-01

474

Finite element analysis of hysteresis motor combined with magnetization-dependent model  

Microsoft Academic Search

This paper presents a method which combines the finite element method with the magnetization-dependent Preisach model for analyzing the hysteresis motor. The proposed method is applied to a sample motor. From the obtained results, it is found that the output torque of the rotor can be estimated by considering harmonic effects due to slot and winding distributions

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

1997-01-01

475

An Analysis of the Hysteresis Motor I - Analysis of the Idealized Machine  

Microsoft Academic Search

This paper presents an analysis of an idealized polyphase hysteresis machine. The distributed magnetic field within the machine is described in terms of dimensions and windings. A single-phase equivalent circuit is developed for the machine and expressions are given for the parameters of this equivalent circuit and for the machine torque. Improvement of power factor by reduction of stator voltage

M. A. Copeland; G. R. Slemon

1963-01-01

476

DSP based torque and speed controls of the permanent magnet hysteresis synchronous motor  

Microsoft Academic Search

This paper presents the detailed derivation of the permanent magnet hysteresis synchronous motor (PMHS) torque equation and the design of the digital speed controller for the DSP based PMHS motor vector control system. The torque control that regulates the speed of the PMHS motor, is provided by a quadrature axis current command developed by the speed controller. The digital speed

Ruifeng Qin; M. A. Rahman

1997-01-01

477

High Gain Observer for Induction Motor in Presence of Magnetic Hysteresis , L. Dugard3  

E-print Network

High Gain Observer for Induction Motor in Presence of Magnetic Hysteresis H. Ouadi1 , F. Giri2 , L in induction motors is considered in this paper. In most previous works, motor observers have been designed significant load torque changes. In this paper, a high gain observer is designed for induction motors based

Paris-Sud XI, Université de

478

Trapping and hysteresis in two-phase flow in porous media: A pore-network study  

E-print Network

. This is especially true for hysteresis in relative permeabilities. The trapping models propose trajectories from. The modifier in the Darcy equation is the relative permeability function, which is usu- ally taken of hydrocarbon, and carbon sequestration problems where trap- ping of CO2 leads to safe underground storage. [4

Wildenschild, Dorthe

479

A KYP lemma and invariance principle for systems with multiple hysteresis non-linearities  

Microsoft Academic Search

Absolute stability criteria for systems with multiple hysteresis non-linearities are given in this paper. It is shown that the stability guarantee is achieved with a simple two part test on the linear subsystem. If the linear subsystem satis® es a particular linear matrix inequality and a simple residue condition, then, as is proven, the non-linear system will be asymptotically stable.

THOMAS PAREÂ; ARASH HASSIBI

2001-01-01

480

Oscillations in a relay control system with hysteresis and time dead zone  

Microsoft Academic Search

We describe the results of a study of dynamic modes and bifurcations in a relay system with hysteresis. An electric drive with a dc motor powered by a static electric power converter in which the motor torque is stabilized by a relay control system is taken as an example. The behavior of such a system is described by a four-dimensional

Zh. T. Zhusubaliyev; E. A. Soukhoterin

2002-01-01

481

Receptor-based models with hysteresis for pattern formation in hydra  

E-print Network

Receptor-based models with hysteresis for pattern formation in hydra Anna Marciniak polyp, namely hydra. The model is defined in the form of a system of reaction­diffusion equations of pattern formation and regulation in hydra. The properties of the model demonstrate a range of stationary

Planqué, Bob

482

Dynamics and hysteresis in square lattice artificial spin-ice G. M. Wysin  

E-print Network

-dimensional spin ice materials that exhibit geometrical frustration effects: not all the pair- wise spin-range dipolar forces, which leads to geometrical frustration. Each island is assumed to possess a three, spin-ice, frustration, magnetic hysteresis, susceptibility. I. INTRODUCTION: SQUARE SPIN ICE

Wysin, Gary

483

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 c