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1

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

2

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

3

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

4

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

5

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

6

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

7

Dynamic hysteresis modelling  

Microsoft Academic Search

A viscous-type dynamic hysteresis model (DHM) is developed. The DHM is compatible with static underlying model of any type and nature (Preisach or non-Preisach). The distinguishing features of the DHM are its arbitrary frequency dependence and the ability to control the shape of the dynamic hysteresis loop. The numerical method for the incorporation of the DHM in magnetodynamic computations is

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

2004-01-01

8

Hysteresis in weak ferromagnets  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

9

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

10

The Unsymmetrical Hysteresis Loop  

Microsoft Academic Search

The paper gives results and analyses of tests to determine losses in hysteresis loops wherein the magnetism is carried through cycles in which limiting values of flux are different in amount or the mean values of flux differ from zero. Such variations of magnetism occur in inductor generators, in teeth of induction machines and in materials magnetized from rectifier circuits,

John D. Ball

1915-01-01

11

Inverse Compensation for Ferromagnetic Hysteresis.  

National Technical Information Service (NTIS)

This paper addresses the validation of an energy-based inverse compensator for hysteresis in ferromagnetic transducers. At moderate to high drive levels such transducers exhibit significant constitutive non-linearities and hysteresis due to domain mechani...

R. C. Smith R. Zrostlik

1999-01-01

12

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

13

Local Hysteresis in Relaxation Oscillators.  

National Technical Information Service (NTIS)

Relaxation oscillations or 'integrate and fire' phenomena are very commonly found in nature. When modulated by an external force a global hysteresis connected with chaos is often encountered. Besides this kind of hysteresis a local form is found in some s...

P. Alstroem B. Christiansen M. T. Levinsen

1988-01-01

14

Moisture Sorption Hysteresis in Wood.  

National Technical Information Service (NTIS)

The occurrence of moisture sorption hysteresis in wood, and several proposed theories for explaining it, are discussed. Hysteresis is shown to be beneficial when wood is in use because it reduces changes in moisture content (lower effective slope of the s...

C. Skaar

1979-01-01

15

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

16

Hysteresis-Loop Overskewing  

NASA Astrophysics Data System (ADS)

The performance of permanent magnets is largely determined by the magnetostatic energy stored in free space (energy product), which depends on both materials properties and magnet geometry. The latter usually differs from laboratory shapes such as spherical samples, and demagnetizing-field corrections must be applied to compare different geometries. However, in nanostructures, especially in thin films, the macroscopic demagnetizing factors D predicted from Maxwell's equations [1] yield unphysical overskewed hysteresis loops [2]. The overskewing is probably a nanoscale effect, but its origin has remained controversial. Our explanation is that nanoscale magnetization processes violate a main condition for the applicability of macroscopy demagnetizing factors, namely the uniform character of the magnetization. In bulk magnets, the magnetization inhomogeneities effectively average to zero, but this is no longer the case if any of the dimension of the magnet becomes small. We explicitly consider granular thin films, where we find a real-structure dependent reduction D, as contrasted to the sometimes assumed infinite slope M(H) at coercivity. --- This research is supported by BREM (RS), ARPA-E, DOE (DJS), and NCMN. --- References: [1] J. A. Osborn, Phys. Rev. 67, 351 (1945); [2] R. Skomski, J.- P. Liu, and D. J. Sellmyer, Phys. Rev. B 60, 7359 (1999).

Skomski, Ralph; George, T. A.; Sellmyer, D. J.

2011-03-01

17

Theory of molecular hysteresis switch  

NASA Astrophysics Data System (ADS)

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

Kozhushner, Mortko; Oleynik, Ivan

2006-03-01

18

Real and causal hysteresis elements.  

PubMed

Hysteresis is a phenomenon that has been observed across many different materials and situations. Under small-amplitude cyclical motion, classical hysteresis designates a constant loss per cycle over a wide range of frequencies. This is also consistent with an increase in losses or attenuation with frequency that is strictly proportional to the first power of frequency. Unfortunately, the classical (and simple) frequency domain description of hysteresis does not result in a real and causal impulse response, and therefore is not useful for predicting laboratory results. This problem has led to many errors as well as other more fruitful approaches over the years. The frequency domain requirements for hysteresis are re-examined and it is demonstrated that there is a family of solutions that provide real and causal impulse responses over some extended frequency range. The family is conveniently divided into highpass, lowpass, and bandpass causal systems. These are populated by closed form analytical solutions which can be applied to the prediction of motion and waves in hysteretic materials and systems. PMID:24907801

Parker, Kevin J

2014-06-01

19

Efficiency Wage, Commitment and Hysteresis  

Microsoft Academic Search

The efficiency wage model is usually thought of as a plausible model of the natural rate of unemployment which has little to say about its dynamics. This paper establishes that if firms pay efficiency wages and have some degree of commitment over their employment policy, then employment dynamics exhibit hysteresis. The implied behaviour of unemployment, however, is more similar to

Gilles SAINT-PAUL

1995-01-01

20

Control of Hysteresis: Theory and Experimental Results.  

National Technical Information Service (NTIS)

Hysteresis in smart materials hinders the wider applicability of such materials in actuators. In this paper, a systematic approach for coping with hysteresis is presented. The method is illustrated through the example of controlling a commercially availab...

X. Tan R. Venkataraman P. S. Krishnaprasad

2001-01-01

21

Temperature Dependent Hysteresis Study in Polyvinylidene Fluoride.  

National Technical Information Service (NTIS)

An experimental study of temperature dependent ferroelectric hysteresis phenomena of polyvinylidene fluoride is presented. The temperature dependence of the remanent polarization and coercive field was measured from saturated ferroelectric hysteresis curv...

R. B. Olsen J. C. Hicks M. G. Broadhurst G. T. Davis

1983-01-01

22

Hysteresis Development in Superconducting Josephson Junctions.  

National Technical Information Service (NTIS)

The resistively and capacitive shunted junction model is used to investigate hysteresis development in superconducting Josephson junctions. Two empirical formulas that relate the hysteresis width and the quasi-particle diffusion length in terms of the jun...

T. F. Refai L. N. Shehata

1988-01-01

23

PSPICE computer modeling of hysteresis effects  

Microsoft Academic Search

Recent versions of PSPICE, a personal computer implementation of the SPICE circuit simulation computer software program, have the capability of simulating the hysteresis loops of magnetic materials. In order to model the hysteresis loop of a particular manufacturer's magnetic core material, the values of five parameters that affect the shape of the hysteresis loop must be established. A method for

S. Prigozy

1993-01-01

24

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

25

Thermal Hysteresis Analysis of MEMS Pressure Sensors  

Microsoft Academic Search

Thermal hysteresis reduction is usually a difficult task to tackle for micromachined pressure sensors especially when shrinking piezoresistive transducer (PRT) sensing elements. Since thermal hysteresis involves the entire thermal cycling history and complicated material properties that vary with temperatures, viscoplastic deformation makes the problem very complicated when dealing with high-precision sensor signals. The approach to simplify and quickly resolve the

J. Albert Chiou; Steven Chen

2005-01-01

26

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

27

A theory of DE hysteresis loop  

Microsoft Academic Search

The D-E hysteresis loop of ferroelectrics is theoretically studied on the basis of the Avrami model, extended for the case of applied field dependent sidewise velocity. The exponent for the frequency dependence of the extended volume is obtained. The exponent of the area of hysteresis loop, with respect to the frequncy, is also obtained.

Yoshihiro Ishibashi; Hiroshi Orihara

1995-01-01

28

Corneal hysteresis following descemetorhexis with endokeratoplasty  

Microsoft Academic Search

The corneal biomechanical properties following descemetorhexis with endokeratoplasty (DXEK) and in normal subjects were studied\\u000a in 100 eyes (12 DXEK and 88 age-matched normal subjects). Corneal hysteresis measurements were significantly lower in DXEK\\u000a vs normal subjects. DXEK has a direct effect on corneal hysteresis and corneal biomechanical properties of the human cornea.

Thomas John; David A. Taylor; Mitsugu Shimmyo; Bruce E. Siskowski

2007-01-01

29

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

30

A thermodynamically consistent model for magnetic hysteresis  

NASA Astrophysics Data System (ADS)

A phenomenological constitutive model is presented to describe the magnetization curve within the context of thermodynamics. Due to the phenomenological analogy between the magnetic hysteresis and the stress hysteresis, the basic structure of the proposed model comes from rate-dependent plasticity in continuum mechanics, namely viscoplasticity. The total magnetic flux density is assumed to be the sum of reversible and irreversible parts. The model introduces the evolution laws of two internal state variables to incorporate the effect of the ever-changing internal microstructure on the current state. The conception originated from viscoplasticity enables the frequency dependence of the hysteresis curve to be modeled.

Ho, Kwangsoo

2014-05-01

31

Free Energy Model for Hysteresis Ferroelectric Materials.  

National Technical Information Service (NTIS)

This paper provides a theory for quantifying the hysteresis and constitutive nonlinearities inherent to piezoceramic compounds through a combination of free energy analysis and stochastic homogenization techniques. In the first step of the model developme...

R. C. Smith Z. Ounaies S. Seelecke J. Smith

2003-01-01

32

Hydrodynamic Model of Dynamic Contact Angle Hysteresis.  

National Technical Information Service (NTIS)

A qualitative hydrodynamic description of dynamic contact angle hysteresis is developed in terms of the interaction of capillary, viscous, and disjoining forces by considerating the slow motion of a fluid-fluid interface being driven through a capillary t...

R. J. Prutow S. Ostrach

1971-01-01

33

Adhesion hysteresis of silane coated microcantilevers  

SciTech Connect

The authors have developed a new experimental approach for measuring hysteresis in the adhesion between micromachined surfaces. By accurately modeling the deformations in cantilever beams that are subject to combined interfacial adhesion and applied electrostatic forces, they determine adhesion energies for advancing and receding contacts. They draw on this new method to examine adhesion hysteresis for silane coated micromachined structures and found significant hysteresis for surfaces that were exposed to high relative humidity (RH) conditions. Atomic force microscopy studies of these surfaces showed spontaneous formation of agglomerates that they interpreted as silages that have irreversibly transformed from uniform surface layers at low RH to isolated vesicles at high RH. They used contact deformation models to show that the compliance of these vesicles could reasonably account for the adhesion hysteresis that develops at high RH as the surfaces are forced into contact by an externally applied load.

DE BOER,MAARTEN P.; KNAPP,JAMES A.; MICHALSKE,TERRY A.; SRINIVASAN,U.; MABOUDIAN,R.

2000-04-17

34

Thermal Hysteresis of Interface Biased Ferromagnetic Dots.  

National Technical Information Service (NTIS)

We present a theoretical investigation of the thermal hysteresis of iron dots exchange-coupled to an antiferromagnetic substrate. We consider a temperature interval bounded by the Neel temperature of the substrate, and we calculate the heating and cooling...

A. L. Dantas, A. S. Carrico, A. S. Silva, G. O. Reboucas, R. E. Camley

2007-01-01

35

Inversion of hysteresis and creep operators  

NASA Astrophysics Data System (ADS)

The explicit inversion formula for rate dependent Prandtl-Ishlinskii operators is extended to cases without the threshold dilation condition. This solves a problem in hysteresis and creep modeling of magnetostrictive behavior.

Krej?í, Pavel; Al Janaideh, Mohammad; Deasy, Fergal

2012-05-01

36

Homogenized Energy Framework for Ferromagnetic Hysteresis.  

National Technical Information Service (NTIS)

In this paper, we develop a macroscopic framework quantifying the hysteresis and constitutive nonlinearities inherent to ferromagnetic materials. In the first step of the development, we construct Helmholtz and Gibbs energy relations at the mesoscopic or ...

R. C. Smith M. J. Dapino T. R. Braun A. P. Mortensen

2005-01-01

37

Experimental comparison of some phenomenological hysteresis models in characterizing hysteresis behavior of shape memory alloy actuators  

Microsoft Academic Search

Among the phenomenological hysteresis models, the Preisach model, Krasnosel’skii–Pokrovskii model, and Prandtl–Ishlinskii model have found extensive applications for modeling hysteresis in shape memory alloys and other smart actuators. Since the mathematical complexity of the identification and inversion problem depends directly on the type of phenomenological hysteresis modeling method, choosing a proper phenomenological model among the mentioned models for modeling the

Mohammad R Zakerzadeh; Hassan Sayyaadi

2012-01-01

38

Hysteresis effects in Bose-Einstein condensates  

SciTech Connect

Here, we consider damped two-component 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 of the appearance of saddle node bifurcations and the damping effect.

Sacchetti, Andrea [Faculty of Sciences, University of Modena e Reggio Emilia, Via Campi 213/B, I-41100 Modena (Italy)

2010-07-15

39

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

40

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

41

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

42

Preisach modeling of piezoceramic and shape memory alloy hysteresis  

Microsoft Academic Search

Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit significant hysteresis, especially when driven with large input signals. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the

Declan C. Hughes; John T. Wen

1996-01-01

43

Preisach modeling of piezoceramic and shape memory alloy hysteresis  

Microsoft Academic Search

Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit hysteresis, and the larger the input signal the larger the effect. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials.

Declan Hughes; John T. Wen

1997-01-01

44

Analysis of a hysteresis motor with overexcitation  

SciTech Connect

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

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

1982-11-01

45

Re-Examination of Mechanical Hysteresis.  

National Technical Information Service (NTIS)

Mechanical-hysteresis loops have been obtained for cycles of torsion applied to copper, brass, low-carbon steel, titanium. It is shown that the slope of the unloading line is determined by a plastic recovery p together with elastic recovery e, that p/e is...

W. A. Wood

1967-01-01

46

Rotational Hysteresis of Exchange-Spring Magnets.  

National Technical Information Service (NTIS)

We highlight our experimental studies and micromagnetic simulations of the rotational hysteresis in exchange-spring magnets. Magneto-optical imaging and torque magnetometry measurements for SmCo/Fe exchange-spring films with uniaxial in-plane anisotropy s...

J. S. Jiang R. D. Shull S. D. Bader H. Kaper A. J. Shapiro

2002-01-01

47

Topological hysteresis in stripe domain structures  

Microsoft Academic Search

Irreversible evolution in stripe domain structures in a bubble material was investigated. Equilibrium parallel stripe structure folds progressively up to the labyrinth one under normal magnetic field cycles. This topological hysteresis, not related to wall-pinning by defects but to nucleation and collapse field problems, shows memory effects of upper fields encountered.

P. Molho; J. Gouzerh; J. C. S. Levy; J. L. Porteseil

1986-01-01

48

Topological hysteresis in stripe domain structures  

NASA Astrophysics Data System (ADS)

Irreversible evolution in stripe domain structures in a bubble material was investigated. Equilibrium parallel stripe structure folds progressively up to the labyrinth one under normal magnetic field cycles. This topological hysteresis, not related to wall-pinning by defects but to nucleation and collapse field problems, shows memory effects of upper fields encountered.

Molho, P.; Gouzerh, J.; Levy, J. C. S.; Porteseil, J. L.

1986-02-01

49

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

50

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

51

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

52

A phenomenological mathematical model of hysteresis  

Microsoft Academic Search

This paper starts with the description of a purely mathematical model of the saturation curve and the hysteresis loop based on the fundamental similarities between the Langevin function the specified T(x) function and the sigmoid shape. The T(x) function which is composed of tangent hyperbolic and linear functions with its free parameters can describe the regular anhysteretic magnetisation curve. Developed

J. Takács

2001-01-01

53

Dynamical aspects of the adsorption hysteresis phenomenon  

Microsoft Academic Search

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,

Rustem Valiullina; Sergej Naumov; Peter A. Monson

54

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

55

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

56

Role of hysteresis in stomatal aperture dynamics  

NASA Astrophysics Data System (ADS)

Stomata are pores responsible for gas exchange in leaves. Several experiments indicate that stomata synchronize into clusters or patches. The patches’ coordination may produce oscillations in stomatal conductance. Previous studies claim to reproduce some experimental results. However, none was able to explain the variety of behavior observed in the stomatal dynamics. Recently, Ferraz and Prado suggested a realistic geometry of vein distribution. Although it reproduces the patches, no oscillation was observed and the patches remain static. Without exploring significant details, the authors stated that hysteresis in stomatal aperture could explain several experimental features. In this paper, the hysteresis hypothesis is further explored through the concept of hysteretic operators. We have shown that the hysteresis assumption is sufficient to obtain dynamical patches and oscillations in stomatal conductance. The robustness of this hypothesis is tested by using different hysteresis operators. The model analysis reveals a dependence between the period of oscillation in stomatal conductance and the water deficit between the leaf and the environment. This underlying feature of the model might inspire further experiments to test this hypothesis.

Ramos, Antônio M. T.; Prado, Carmen P. C.

2013-01-01

57

Geometric Hysteresis of Alveolated Ductal Architecture  

PubMed Central

Low Reynolds number airflow in the pulmonary acinus and aerosol particle kinetics therein are significantly conditioned by the nature of the tidal motion of alveolar duct geometry. At least two components of the ductal structure are known to exhibit stress-strain hysteresis: smooth muscle within the alveolar entrance rings, and surfactant at the air-tissue interface. We hypothesize that the geometric hysteresis of alveolar duct is largely determined by the interaction of the amount of smooth muscle & connective tissue in ductal rings, septal tissue properties, and surface tension-surface area characteristics of surfactant. To test this hypothesis, we have extended the well-known structural model of the alveolar duct by Wilson and Bachofen (J. Appl. Physiol. 52(4): 1064–1070, 1982) by adding realistic elastic and hysteretic properties of 1) the alveolar entrance ring, 2) septal tissue, and 3) surfactant. With realistic values for tissue and surface properties, we conclude that: 1) there is a significant, and underappreciated, amount of geometric hysteresis in alveolar ductal architecture; and 2) the contribution of smooth muscle and surfactant to geometric hysteresis are of opposite senses, tending toward cancellation. Quantitatively, the geometric hysteresis found experimentally by Miki et al. (J. Appl. Physiol. 75(4): 1630–1636, 1993) is consistent with little or no smooth muscle tone in anesthetized rabbits in control conditions, and with substantial smooth muscle activation following methacholine challenge. The observed local hysteretic boundary motion of the acinar duct would result in irreversible acinar flow fields, which might be important mechanistic contributors to aerosol mixing and deposition deep in the lung.

Kojic, M.; Butler, J. P.; Vlastelica, I.; Stojanovic, B.; Rankovic, V.; Tsuda, A.

2013-01-01

58

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

59

Hysteresis Loss as a Measure of Metal-Rubber Adhesion  

Microsoft Academic Search

As in the case of reinforcing-filler-induced increase in hysteresis in rubbers, attachment of aluminium (Al) foil onto the surface of a rubber blend (chlorobutyl rubber-carboxylated nitrile rubber) also causes an increase in hysteresis of the rubber. Changes in the hysteresis loss due to Al foil can be correlated with the Al\\/rubber adhesion.

Tinku Bhattacharya; S. K. De

1993-01-01

60

Hysteresis and gold in metal-insulator-semiconductor (MIS) capacitors  

Microsoft Academic Search

Measurements on gold diffused MIS capacitors, using different dielectric materials, have shown that in addition to changing the surface charge densities present at the silicon-dielectric interface, the gold also reduces the voltage hysteresis commonly observed in the capacitor C-V curves. Some orientation dependent hysteresis results, taken with these gold results, would indicate that the centres responsible for the hysteresis are

S. D. BROTHERTON

1968-01-01

61

Analysis of wasp-waisted hysteresis loops in magnetic rocks.  

PubMed

The random-field Ising model of hysteresis is generalized to dilute magnets and is solved on a Bethe lattice. Exact expressions for the major and minor hysteresis loops are obtained. In the strongly dilute limit the model provides a simple and useful understanding of the shapes of hysteresis loops in magnetic rock samples. PMID:22400529

Kharwanlang, R S; Shukla, Prabodh

2012-01-01

62

Quantum Hydrodynamic Simulation of Hysteresis in the Resonant Tunneling Diode  

Microsoft Academic Search

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

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

1995-01-01

63

Modeling of Hysteresis Losses Applied to Slotless Permanent Magnet Motors  

Microsoft Academic Search

The paper presents a method to determine hysteresis losses in synchronous permanent magnet (PM) slotless motors. The method comprises four steps : (1) experimental determination of the B-H loop, (2) analytical modeling of the B-H loop by applying different models, (3) analytical modeling of the hysteresis losses, and (4) determination of the hysteresis losses in a synchronous PM motor, and

Pierre-Daniel Pfister; Christian Koechli; Miroslav Markovic; Y. Perriard

2007-01-01

64

Analysis of Hysteresis Losses in Synchronous Permanent Magnet Motors  

Microsoft Academic Search

The paper presents a method to determine hysteresis losses in synchronous permanent magnet (PM) motors. The method comprises four steps: (1) experimental determination of the B-H loop, (2) analytical modeling of the B-H loop by applying different models, (3) analytical modeling of the hysteresis losses, and (4) determination of the hysteresis losses in a synchronous PM motor, and results' verification

P.-D. Pfister; C. Koechli; M. Markovic; Y. Perriard

2006-01-01

65

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

66

Sorption hysteresis of benzene in charcoal particles.  

PubMed

Charcoal is found in water, soil, and sediment where it may act as a sorbent of organic pollutants. The sorption of organic compounds to natural solids often shows hysteresis. The purpose of this study was to determine the source of pronounced hysteresis that we found in the sorption of a hydrophobic compound (benzene) in water to a maple-wood charcoal prepared by oxygen-limited pyrolysis at 673 K. Gas adsorption (N2, Ar, CO2), 13C NMR, and FTIR show the charcoal to be a microporous solid composed primarily of elemental (aromatic) C and secondarily of carboxyl and phenolic C. Nonlocal density functional theory (N2, Ar) and Monte Carlo (CO2) calculations reveal a porosity of 0.15 cm3/g, specific surface area of 400 m2/g, and appreciable porosity in ultramicropores < 10 A. Benzene sorption-desorption conditions were chosen to eliminate artificial causes of hysteresis (rate-limiting diffusion, degradation, colloids effect). Charcoal sorbed up to its own weight of benzene at approximately 69% of benzene water solubility. Sorption was highly irreversible over most of the range tested (10(-4)-10(3) microg/mL). A dimensionless irreversibility index (/i) (0 < or = /i < or = 1) based on local slopes of adsorption and desorption branches was evaluated at numerous places along the isotherm. /i decreases as C increases, from 0.9-1 at low concentration to approximately 0 (approximately fully reversible) at the highest concentrations. Using sedimentation and volumetric displacement measurements, benzene is observed to cause pronounced swelling (up to > 2-fold) of the charcoal particles. It is proposed that hysteresis is due to pore deformation by the solute, which results in the pathway of sorption being different than the pathway of desorption and which leads to entrapment of some adsorbate as the polyaromatic scaffold collapses during desorption. It is suggested that intra-charcoal mass transport may be influenced by structural rearrangement of the solid, in addition to molecular diffusion. PMID:12564916

Braida, Washington J; Pignatello, Joseph J; Lu, Yuefeng; Ravikovitch, Peter I; Neimark, Alexander V; Xing, Baoshan

2003-01-15

67

Role of reversible susceptibility in ferromagnetic hysteresis  

NASA Astrophysics Data System (ADS)

An equation of state based upon saturation magnetization, Ms, coercive field, Hc, and the reversible susceptibility function of magnetization is proposed for ferromagnetic hysteresis. Reversible susceptibility divided by the initial susceptibility is the anisotropy function of magnetization, ?r, ranging from one in the demagnetized state to zero at saturation, and varying with magnetic history. Its dependence on scaled magnetization, m=M/Ms on the interval (-1,1) varies with material, allowing characterization of anisotropy classes. Precise measurements have been made of reversible susceptibility, initial and saturate magnetization curves, and loops for Orthonol™, annealed 3% nickel steel and as-received 1018 steel, representing crystals, isotropic polycrystals and composite ferromagnets, respectively. Magnetization change is the product of the reversible susceptibility, change in the applied field and the cooperative function due to domain interactions. This function is 1+?m for the virgin curve with half this slope from any reversal, where ?=Ms/XiHc is the hysteresis coefficient. Variation of ? for 1018 steel is due to distributed coercivities, and causes sigmoid B(H) curves. In the scaled field representation, where h=H/Hc, the cooperative function is 1/(1-h?r), a hyperbolic field dependence smeared by the anisotropy function. Constant anisotropy causes closed hysteresis loops, while variable anisotropy causes creeping of cycled asymmetric loops. In ferromagnetism, 1/?=1/?r-h, normal scaled reluctivity is reduced from its reversible value by the scaled field.

Schneider, Carl S.

2002-05-01

68

Hysteresis in stress cycling of amorphous ribbons  

NASA Astrophysics Data System (ADS)

The permeability of soft amorphous ribbons shows significant hysteresis through stress cycling. The response of a circuit incorporating an amorphous CoFeNiSiB based ribbon, as a function of longitudinal stress, with a longitudinal excitation field, is measured. The behaviour of the stress impedance is related to domain wall behaviour, at a range of different frequencies, through a simple model of eddy currents in sheets. It is suggested that changes in the pinning mechanism have a profound effect on the measured impedance.

Tomka, G. J.; Milne, J.; Tweed, S.; Thomas, O.

2004-05-01

69

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

70

Mechanical hysteresis due to microplasticity in alumina with microcracks  

Microsoft Academic Search

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

Y. Nishino; H. Ogawa; S. Asano

1992-01-01

71

Hysteresis phenomena of the intelligent driver model for traffic flow.  

PubMed

We present hysteresis phenomena of the intelligent driver model for traffic flow in a circular one-lane roadway. We show that the microscopic structure of traffic flow is dependent on its initial state by plotting the fraction of congested vehicles over the density, which shows a typical hysteresis loop, and by investigating the trajectories of vehicles on the velocity-over-headway plane. We find that the trajectories of vehicles on the velocity-over-headway plane, which usually show a hysteresis loop, include multiple loops. We also point out the relations between these hysteresis loops and the congested jams or high-density clusters in traffic flow. PMID:17677531

Dahui, Wang; Ziqiang, Wei; Ying, Fan

2007-07-01

72

Optical hysteresis in liquid crystals with helicoidal distributed feedback  

SciTech Connect

A new method is reported whereby optical hysteresis and optical bistability are achieved through resonant absorption of light by an impurity in a cholesteric liquid crystal with a natural helicoidal distributed feedback. The resonant absorption in this system leads to an optical hysteresis at comparatively low light intensities, with a short response time and a simultaneous polarization of light. An implementation of the method is described in which cavity-free optical hysteresis has been achieved with a threshold energy of 10 to the -5th J or less and a response time of 10 to the -8th s. Such a hysteresis may find applications in optical information processing. 7 references.

Zagainova, L.I.; Klimusheva, G.V.; Kryzhanovskii, I.P.; Kukhtarev, N.V.

1985-11-01

73

Hysteresis effects in edge poloidal flow generation  

NASA Astrophysics Data System (ADS)

Gas puffing at the edge of the TJ-II stellarator has been used to control the development of an edge poloidal velocity shear layer [1]. Recent experiments have been done to test for hysteresis in the development of the flow. In this work, a numerical transport model is used to examine for hysteresis in the development of an edge poloidal velocity shear layer due to a modeled gas puff. The transport model couples together density, ion temperature, electron temperature, poloidal flow, toroidal flow, radial electric field, and a fluctuation envelope equation which includes a shear-suppression factor. The physics of the model has been modified to include a turbulence growth rate for resistive ballooning modes as well as ion temperature gradient modes. The numerical integration in the model has been changed to a modified Runge-Kutta with adaptive time-stepping. For the cases run with parameters consistent with these TJ-II experiments (only RF heating, no neutral beams), the resistive ballooning mode growth rate is dominant in the edge region. In this work, we present results from a series of cases using parameters that are typical of TJ-II discharges and ramps (both up and down) of an edge density source term used to model a gas puff. The impact of the ramp on the generation of edge poloidal velocity is discussed. [1] C. Hidalgo, et al., Phys. Rev. E 70, 067402 (2004).

Fetscher, B.; Newman, D. E.; Carreras, B. A.; Hidalgo, C.

2005-10-01

74

Corneal hysteresis in patients with dry eye  

PubMed Central

Purpose To measure corneal hysteresis and intraocular pressure (IOP) in patients with dry eye and to compare with normal subjects. Methods This cross-sectional study consists of 70 eyes of 40 patients with dry eye (group 1) and 75 eyes of 40 normal subjects (group 2). Eyes were diagnosed as dry eye or normal according to the clinical symptoms, biomicroscopical evaluation, and Schirmer test. Corneal hysteresis (CH), corneal resistance factor (CRF), and cornea-compensated intraocular pressure (IOPcc) were measured by the Ocular Response Analyser (ORA). Results Mean CH values were 10.56±0.25?mm?Hg and 10.34±0.26?mm?Hg, mean CRF values were 10.75±0.28?mm?Hg and 10.70±0.28?mm?Hg, mean CCT values were 542±3.20??m and 543±3.89??m in group 1 and group 2, respectively. There was no statistically significant difference between the groups for these three parameters. IOPcc values measured with ORA were 15.73±0.36?mm?Hg in group 1 and 16.60±0.33?mm?Hg in group 2, and there was no statistically significant difference between the two groups. Conclusions Corneal biomechanical parameters such as CH and CRF are not influenced in dry eye. Also statistical difference was not found between the two groups according to CCT and IOPcc values.

Firat, P G; Doganay, S

2011-01-01

75

A new dynamic model of hysteresis in harmonic drives  

Microsoft Academic Search

In this paper, we propose a new dynamic model to describe the hysteresis phenomenon in harmonic drives. The experimental observation of the dynamic torque-displacement relationship for a harmonic drive shows a hysteresis characteristic indicating the simultaneous presence of energy storage and energy dissipation mechanisms. To completely characterize these mechanisms and yet have a simple representation for control, we develop a

Rached Dhaouadi; Fathi H. Ghorbel; Prasanna S. Gandhi

2003-01-01

76

Study of a Low-Inertia Hysteresis Motor.  

National Technical Information Service (NTIS)

A rotary-drive vibratory-output two-degrees-of-freedom gyro was utilized in a rotor structure of an axial air gap hysteresis motor containing anisotropic barium ferrite and Al-alloy plates. The barium ferrite was used for its large hysteresis loop, small ...

H. Yamada

1975-01-01

77

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

78

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

79

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

80

Sensorless evaluation of asymmetric hysteresis loops of ferromagnetic materials  

Microsoft Academic Search

The sensorless determination of the dynamic hysteresis loop of magnetic materials, and in particular those of magnetic plates, can be obtained under ac symmetric conditions in a relatively simple way. This paper proposes a new digital method and instrument for the sensorless evaluation of the dynamic hysteresis loop under ac asymmetric conditions, in the presence of a dc polarization of

Loredana Cristaldi; Alessandro Ferrero; Massimo Lazzaroni; Adriano P. Morando

2003-01-01

81

Minor Hysteresis Loop in Fe Metal and Alloys  

Microsoft Academic Search

The minor hysteresis loops were measured with increasing magnetic field amplitude Ha step by step and analyzed in Fe single crystal, polycrystalline metals and A533B steel. We have defined several new magnetic properties in the minor loops: they are pseudo magnetization {Ba}*, pseudo coercive force {Hc}*, pseudo remanence {BR}*, pseudo hysteresis loss {WF}*, pseudo remanence work {WR}*, and three pseudo

Seiki Takahashi; Lefu Zhang

2004-01-01

82

Corneal hysteresis following descemetorhexis with endokeratoplasty: early results.  

PubMed

The corneal biomechanical properties following descemetorhexis with endokeratoplasty (DXEK) and in normal subjects were studied in 100 eyes (12 DXEK and 88 age-matched normal subjects). Corneal hysteresis measurements were significantly lower in DXEK vs normal subjects. DXEK has a direct effect on corneal hysteresis and corneal biomechanical properties of the human cornea. PMID:17914199

John, Thomas; Taylor, David A; Shimmyo, Mitsugu; Siskowski, Bruce E

2007-01-01

83

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

84

International Workshop on Multi-Rate Processes and Hysteresis  

Microsoft Academic Search

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

Michael P Mortell; Robert E OMalley; Alexei Pokrovskii; Dmitrii Rachinskii; Vladimir A Sobolev

2008-01-01

85

PREFACE: International Workshop on Multi-Rate Processes and Hysteresis  

Microsoft Academic Search

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

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

2008-01-01

86

Energy-based hysteresis model for magnetostrictive transducers  

Microsoft Academic Search

This paper addresses the modeling of hysteresis in magnetostrictive transducers in the context of control applications that require an accurate characterization of the relation between input currents and strains output by the transducer. This relation typically exhibits significant nonlinearities and hysteresis because of inherent properties of magnetostrictive materials. The characterization considered here is based on the Jiles-Atherton mean field model

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

2000-01-01

87

Potbellies, wasp-waists, and superparamagnetism in magnetic hysteresis  

Microsoft Academic Search

Because the response of a magnetic substance to an applied field depends strongly on the physical properties of the material, much can be learned by monitoring that response through what is known as a ``magnetic hysteresis loop.'' The measurements are rapid and quickly becoming part of the standard set of tools supporting paleomagnetic research. Yet the interpretation of hysteresis loops

L. Tauxe; T. A. T. Mullender; T. Pick

1996-01-01

88

Hysteresis behavior of the anisotropic quantum Heisenberg model  

NASA Astrophysics Data System (ADS)

The effect of the anisotropy in the exchange interaction on the hysteresis loops within the anisotropic quantum Heisenberg model has been investigated with the effective field theory for two spin cluster. Particular attention has been devoted on the behavior of the hysteresis loop area, coercive field and remanent magnetization with the anisotropy in the exchange interaction for both ferromagnetic and paramagnetic phases.

Ak?nc?, Ümit

2013-10-01

89

Hysteresis in Thin-Film Rechargeable Lithium Batteries.  

National Technical Information Service (NTIS)

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 attribute...

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

1999-01-01

90

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

91

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

92

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

Kazumi Kurihara; M. Azizur Rahman

2002-01-01

93

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

94

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

95

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

96

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

97

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

98

Windmill speed limiting system utilizing hysteresis  

SciTech Connect

A windmill speed limiting device is provided to prevent the windmill blades from going too fast during conditions of heavy winds. In order to slow down the windmill blades, the tips of the blades are turned relative to the main blade portion at high speeds. After the tips are turned, the windmill blade must return to a safe speed before the tips are returned to their normal position. A hysteresis effect by which the tip portions are rotated to their normal angular position in alignment with the main blade portion is implemented by means of a cam track, a pivot point below the center of the blade and a central spring loaded drum to which each of the blades are connected.

Barnes, D.R.

1983-02-22

99

Wave tunneling and hysteresis in nonlinear junctions.  

PubMed

We consider the nonlinear tunneling of a plane wave through a small barrier potential in a medium with self-defocusing, or repulsive, interactions. We show that nonlinearity can either suppress or enhance transmission rates, determined by whether the initial kinetic energy is above or below the barrier height. Associated with this threshold is the appearance of two distinct hysteresis loops, going clockwise or counterclockwise, respectively. Spatial dynamics upon reflection and transmission reveals the formation of dispersive shock waves (dark soliton trains) due to phase jumps at the interfaces and wave steepening during propagation. The results are demonstrated experimentally for optical wave tunneling through a refractive index defect but will hold for any Schrödinger system that contains a nonlinear junction. PMID:20366886

Wan, Wenjie; Muenzel, Stefan; Fleischer, Jason W

2010-02-19

100

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

101

Hysteresis in pressure-driven DNA denaturation.  

PubMed

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

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

2012-01-01

102

Hysteresis in Pressure-Driven DNA Denaturation  

PubMed Central

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

Hernandez-Lemus, Enrique; Nicasio-Collazo, Luz Adriana; Castaneda-Priego, Ramon

2012-01-01

103

Hysteresis and bistability in periodically paced cardiac tissue  

NASA Astrophysics Data System (ADS)

Hysteresis in periodically paced cardiac tissue is an important issue due to its relevance to cardiac arrhythmias. In the present paper, the mechanism of hysteresis formation and the related properties are interpreted by numerically investigating the phase I Luo-Rudy model. A formula calculating the width of hysteresis is proposed and well confirmed by numerical simulations. We also find that hysteresis in cardiac tissue shows several characteristics due to couplings among cardiac cells which are absent in a single cell. The influences of the physiological parameters are studied in detail. The model dependence of hysteresis is elucidated by considering a number of well-known models of excitable media. Moreover, the influence of bistability on controlling arrhythmias is revealed.

Huang, Xiaodong; Qian, Yu; Zhang, Xiaoming; Hu, Gang

2010-05-01

104

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

105

Sediment Hysteresis Patterns In Singapore Urban Residential Lined Channels  

NASA Astrophysics Data System (ADS)

A study involving Jurong West (JW)(68.7 ha) and Ang Mo Kio (AMK)(34.9 ha) residential catchments in Singapore was conducted to analyse temporal total suspended sediment concentrations (TSS) in lined drainage channels during rain events. 53 and 25 storm events were sampled respectively for JW and AMK. 3 types of hysteresis patterns namely, clockwise, eight shaped and random shaped were identified. Data suggested that different impervious cover configurations in both catchments has accounted for different types of hysteresis patterns. Higher impervious cover (84%) in JW produced mainly clockwise, followed by eight shaped and random hysteresis patterns. Lower impervious cover (60%) in AMK produced mainly clockwise hysteresis. Eight shaped and random hysteresis only appeared in AMK when sediment sources like construction activities emerged. Data also showed eight shaped and random hysteresis appeared during higher magnitude of rain events in JW catchment. Different configurations of impervious cover in both catchments also resulted in variations of TSS during rain events. This led to different tightness of hysteresis patterns loops in both catchments. Conclusively, this study has shown that degree of impervious cover, rain magnitude and emergence of new sediment sources in small urban residential has effects on temporal loadings and variations of sediment in small urban residential catchments.

Lee, W.

2006-12-01

106

Hysteresis prediction for piezoceramic actuator systems using Preisach models  

NASA Astrophysics Data System (ADS)

Hysteresis is a form of nonlinearity that is present in piezoceramic microactuator systems. A methodology to predict influence of hysteresis on system performance is valuable when these actuators are employed as part of closed loop motion control systems. In this work, an existing phenomenological approach (Preisach models) is investigated for piezoceramic systems. Hysteresis in a piezoceramic system is experimentally documented initially for a bounding operating condition of a cyclic electric potential. The limiting hysteresis loop has a positive turning point of +100 V and a negative turning point of -100 V. Hysteretic behavior for various operating conditions within this bounding loop (i.e. minor hysteresis loops) is then predicted using a moving Preisach model. In addition, hysteresis effects are analytically predicted when a constant mechanical load and a cyclic electric potential are applied simultaneously, using two inputs Preisach model. Experimental data are also presented for the minor hysteresis loops at different positive and negative turning points. Predictions using Preisach models agreed well with the experimental results, particularly when the minor loops are closer to the bounding loop.

Sreeram, Puduhai N.; Naganathan, Nagi G.

1994-05-01

107

Modelling hysteresis in magnetically ordered materials  

NASA Astrophysics Data System (ADS)

This thesis presents a generalized version of the Preisach model of hysteresis which is designed to describe the temperature dependence and field dependence of the irreversible response of magnetically ordered materials everywhere below their critical temperature Tc. The model decomposes the magnetizing process into a sequence of Barkhausen events, each of which is represented by a double well potential with moment mu two states ? = +/-mu, a dissipation energy Wd = mu hc and a stored energy Ws = 2muhi. A given magnetic material is characterized by an ensemble of Barkhausen elements with a distribution of characteristic fields p(hc, hi). The distribution is allowed to vary with temperature in order to reflect intrinsic variations with temperature of the anisotropy and pinning mechanisms, in such a way that the coercive field distribution collapses into a delta-function delta( hc) as T approaches Tc from below. Thermal fluctuations are represented by a thermal viscosity field h*T = (kBT/mu)ln( texp/tau0). The model was used to simulate numerically various standard experimental response functions, including the temperature dependence of the zero field cooled moment in a fixed applied field ha, the temperature dependence of the field cooled moment in a fixed applied field, initial magnetizing and major hysteresis loop isotherms, and remanences, and the influence of each model parameter on the magnetic response functions was studied systematically. The model simulation sidentified the ratio eta of the mean zero temperature dissipation barrier W¯d(0) to the critical thermal fluctuation energy Wc = k BTcln(texp/tau 0) ass an important parameter which influences the principal structural characteristics of the response, and which can be used to classify materials as fluctuation-dominated or anisotropy-dominated. The model was applied to the analysis of the measured response functions five systems, two nanoparticulate systems, Fe/SiO 2 and NiFe2O 4, which were fluctuation-dominated, and three ferromagnetic perovskites SrRuO3, La0.5Sr 0.5-CoO3, and La0.7 Sr0.3MnO3, which were anisotropy-dominated. The analysis yielded the spectrum of Barkhausen characteristic fields p(hc, hi, T) and the Barkhausen moment mu(T), from which it is possible to reconstruct a physical picture of the evolution of the Barkhausen free energy barriers with temperature, as well as some description of the reversible component of the response.

Song, Tiancheng

2003-06-01

108

Understanding the hysteresis loop conundrum in pharmacokinetic / pharmacodynamic relationships.  

PubMed

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

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

2014-01-01

109

Bistable hysteresis and resistance switching in hydrogen-gold junctions  

NASA Astrophysics Data System (ADS)

Current-voltage characteristics of H2-Au molecular junctions exhibit intriguing steps around a characteristic voltage of Vs?40mV . Surprisingly, we find that a hysteresis is connected to these steps with a typical time scale >10ms . This time constant scales linearly with the power dissipated in the junction beyond an off-set power Ps=IVs . We propose that the hysteresis is related to vibrational heating of both the molecule in the junction and a set of surrounding hydrogen molecules. Remarkably, by stretching the junction the hysteresis’ characteristic time becomes >days . We demonstrate that reliable switchable devices can be built from such junctions.

Trouwborst, M. L.; Huisman, E. H.; van der Molen, S. J.; van Wees, B. J.

2009-08-01

110

Drag force measurement: A means for determining hysteresis loss  

SciTech Connect

A method for determining hysteresis losses in thin strips of soft magnetic materials is described. It is based on the measurement of a drag force which arises with the movement of the sample through the strong field existing in the space near a permanent magnet. Not associated with macro eddy currents, the force is shown to originate from the magnetic hysteresis of the material, having, in fact, an amplitude equal to the product of hysteresis loss and the area of the sample cross section. Correlation within 18% with the measurements made by conventional methods is shown for a wide range of experimental materials.

Garshelis, Ivan J.; Tollens, Stijn P. L.; Kari, Ryan J.; Vandenbossche, Lode P.; Dupre, Luc R. [Magnova, Inc., Pittsfield, Massachusetts 01201 and MagCanica, Inc., San Diego, California 92117 (United States); MagCanica, Inc., San Diego, California 92117 (United States); Department of Electrical Energy, Systems and Automation, Ghent University, Ghent B-9000 (Belgium)

2006-04-15

111

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

112

Hysteresis and nonlinear elasticity in rocks  

SciTech Connect

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

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

1993-12-01

113

Titration and hysteresis in epigenetic chromatin silencing.  

PubMed

Epigenetic mechanisms of silencing via heritable chromatin modifications play a major role in gene regulation and cell fate specification. We consider a model of epigenetic chromatin silencing in budding yeast and study the bifurcation diagram and characterize the bistable and the monostable regimes. The main focus of this paper is to examine how the perturbations altering the activity of histone modifying enzymes affect the epigenetic states. We analyze the implications of having the total number of silencing proteins, given by the sum of proteins bound to the nucleosomes and the ones available in the ambient, to be constant. This constraint couples different regions of chromatin through the shared reservoir of ambient silencing proteins. We show that the response of the system to perturbations depends dramatically on the titration effect caused by the above constraint. In particular, for a certain range of overall abundance of silencing proteins, the hysteresis loop changes qualitatively with certain jump replaced by continuous merger of different states. In addition, we find a nonmonotonic dependence of gene expression on the rate of histone deacetylation activity of Sir2. We discuss how these qualitative predictions of our model could be compared with experimental studies of the yeast system under anti-silencing drugs. PMID:23588040

Dayarian, Adel; Sengupta, Anirvan M

2013-06-01

114

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

115

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

116

Energy-Based Hysteresis Model for Magnetostrictive Transducers.  

National Technical Information Service (NTIS)

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 transduc...

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

1997-01-01

117

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?

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

2013-01-01

118

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

119

PREFACE: International Workshop on Hysteresis & Multi-scale Asymptotics  

NASA Astrophysics Data System (ADS)

An International Workshop on Hysteresis & Multi-scale Asymptotics was held at University College Cork, Ireland on March 17-21, 2004. It brought together about 40 active scientists in the areas of dynamical systems with hysteresis and singular perturbations to analyse these phenomena which occur in many industrial, physical and economic systems. The scientific programme of the Workshop can be downloaded from the homepage http://euclid.ucc.ie/hamsa2004.htm. This collection of invited papers is based on the programme of the workshop whose main goal was to analyse and to demonstrate an interaction between theories of systems with multiple scales and systems with hysteresis (and between the 'multi-scale' and 'hysteresis' research communities) as far as possible. To fully understand the paths from singular perturbations to hysteresis and from hysteresis to singular perturbations will continue to involve much work and intense interdisciplinary interactions among experts in the two areas. We mention also two previous workshops: International Workshop on Relaxation Oscillations & Hysteresis, University College Cork, Ireland, April 1-6, 2002. The related collection, edited by us, was published as 'Singular Perturbations and Hysteresis', SIAM, Philadelphia, 2005. http://www.ucc.ie/ucc/depts/physics/ins/roh2002.htm International Workshop on Geometrical Methods of Nonlinear Analysis and Semiconductor Laser Dynamics, University College Cork, Ireland, April 5-6, 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, Vol. 5, 2001, No 1 and 2 (edited by Vladimir Gol'dstein, Alexei Pokrovskii and Vladimir Sobolev), and is also available online at http://euclid.ucc.ie/appliedmath/gmna2001/ProcGMNA2001Full.pdf Finally, we wish to gratefully acknowledge the support of the School of Mathematical Sciences and the Boole Centre for Research in Informatics, University College Cork.

Mortell, Michael; O'Malley, Robert E.; Pokrovskii, Alexei; Sobolev, Vladimir

2005-01-01

120

Thermal-expansion hysteresis in graphite\\/glass composites  

Microsoft Academic Search

The thermal-expansion hysteresis phenomena in graphite\\/glass composites was studied. Neat (unfilled) glass and unidirectional composites showed no observable hysteresis, while (0\\/90) cross-ply composites showed significant residual thermal strain (approx. 20 PPM) after thermal cycling (25 ..-->.. 150 ..-->.. 25°C). Multiple thermal cycling of the composite and the strengthening of the fiber\\/matrix bond were found to greatly reduce the magnitude of

Janas

1988-01-01

121

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

122

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.

Wilson, P W; Leader, J P

1995-01-01

123

Generalized hysteresis current controller for three-level inverter topologies  

Microsoft Academic Search

This paper analyzes the generalized hysteresis current control algorithm for three level inverter topologies. The inverter topologies considered are H-bridge, diode clamped and capacitor clamped three level inverters. It is shown that the switching frequency for the proposed hysteresis algorithm can be estimated using an empirical relation. The algorithm can be directly implemented for the H-bridge and diode clamped three-level

Shweta Gautam; Rajesh Gupta

2012-01-01

124

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

125

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

126

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

127

Modeling and characterization for polarization hysteresis of ferroelectric polymers  

Microsoft Academic Search

We present a modeling and simulation based study for the polarization hysteresis of ferroelectric polymers. A 2- dimensional finite element device-level model was implemented using SILVACO's ATLAS device simulator to generate the polarization hysteresis characteristics for the recently reported experimental data on Au\\/Poly(vinylidene fluoride- trifluoroethylene)\\/Au metal-insulator-metal (MIM) device. The simulated polarization dependence characteristics in the P(VDF-TrFE) thin-film were predicted from

Bikash Shrestha; Ron Pieper; Wudyalew Wondmagegn; Nikhil Satyala

2011-01-01

128

Perceptual hysteresis in the judgment of auditory pitch shift.  

PubMed

Perceptual hysteresis can be defined as the enduring influence of the recent past on current perception. Here, hysteresis was investigated in a basic auditory task: pitch comparisons between successive tones. On each trial, listeners were presented with pairs of tones and asked to report the direction of subjective pitch shift, as either "up" or "down." All tones were complexes known as Shepard tones (Shepard, 1964), which comprise several frequency components at octave multiples of a base frequency. The results showed that perceptual judgments were determined both by stimulus-related factors (the interval ratio between the base frequencies within a pair) and by recent context (the intervals in the two previous trials). When tones were presented in ordered sequences, for which the frequency interval between tones was varied in a progressive manner, strong hysteresis was found. In particular, ambiguous stimuli that led to equal probabilities of "up" and "down" responses within a randomized context were almost fully determined within an ordered context. Moreover, hysteresis did not act on the direction of the reported pitch shift, but rather on the perceptual representation of each tone. Thus, hysteresis could be observed within sequences in which listeners varied between "up" and "down" responses, enabling us to largely rule out confounds related to response bias. The strength of the perceptual hysteresis observed suggests that the ongoing context may have a substantial influence on fundamental aspects of auditory perception, such as how we perceive the changes in pitch between successive sounds. PMID:24874257

Chambers, Claire; Pressnitzer, Daniel

2014-07-01

129

Synchronous neural networks of nonlinear threshold elements with hysteresis.  

PubMed Central

We use Hoffmann's suggestion [Hoffmann, G. W. (1986) J. Theor. Biol. 122, 33-67] of hysteresis in a single neuron level and determine its consequences in a synchronous network made of such neurons. We show that the overall retrieval ability in the presence of noise and the memory capacity of the network in the present model are better than in conventional models without such hysteresis. Second-order interaction further improves the retrieval ability of the network and causes hysteresis in the retrieval-noise curve for any arbitrary width of the bistable region. The convergence rate is increased by the hysteresis at high noise levels but is reduced by the hysteresis at low noise levels. Explicit formulae are given for calculations of average final convergence and noise threshold as functions of the width of the bistable region. There is neurophysiological evidence for hysteresis in single neurons, and we propose optical implementations of the present model by using ZnSe interference filters to test the predictions of the theory.

Wang, L; Ross, J

1990-01-01

130

Adhesion hysteresis and friction at nanometer and micrometer lengths  

SciTech Connect

Comparisons between adhesion hysteresis and friction at nanometer and micrometer length scales were investigated experimentally and theoretically. Nanoscale adhesion hysteresis was measured using the ultrasonic force microscopy (UFM) on mica, calcite, and a few metallic samples (Pt, Au, Cu, Zn, Ti, and Fe). Obtained adhesion hysteresis ranged between 4x10{sup -19} and 4x10{sup -18} J. At the microscale a similar setup with a nanoindenter was used and the same samples were investigated. Adhesion hysteresis measured at the microscale ranged between 8x10{sup -17} and 14x10{sup -17} J. Friction was investigated via lateral force microscopy, as well as by scratch tests done with the nanoindenter. Numerical simulations based on the UFM model as well as established theories of contact mechanics studied qualitative dependencies of adhesion hysteresis on experimental parameters. Quantitative relations between adhesion hysteresis and friction were obtained through an analytic model relying on elastic and adhesive properties of the contact. The model agreed with measurements and simulations.

Szoszkiewicz, Robert; Bhushan, Bharat; Huey, Bryan D.; Kulik, Andrzej J.; Gremaud, Gerard [Georgia Institute of Technology, School of Physics, 837 State Street, Atlanta, Georgia 30332 (United States); Nanotribology Laboratory for Information Storage and MEMS/NEMS (NLIM), Ohio State University, Columbus, Ohio 43210 (United States); Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Institute of Physics of Complex Matter, EPFL, CH-1015 Lausanne (Switzerland)

2006-01-01

131

Influence of magnetostriction on hysteresis loss of electrical steel sheet  

NASA Astrophysics Data System (ADS)

To reveal influence of magnetostriction on hysteresis loss of electrical steel sheet, hysteresis loss and magnetostriction of non-oriented electrical steel sheets (NOs) with various Si and Al content and grain size and grain oriented electrical steel sheet (GO) were measured under compressive or tensile stress. Here, Si and Al content and stress were focused on as the way to change magnetostriction. Stress direction and magnetizing direction were parallel to the rolling direction. Following three main results were obtained. The first is hysteresis loss of NO with same grain size which increased with magnetostriction independently of Si and Al content and stress. The second is hysteresis loss of NO was larger than that of GO under same magnetostriction. The third is hysteresis loss of NO at magnetostriction of zero was inversely proportional to grain size. Even if the grain size of NO increased to be similar size of GO without changing texture, the hysteresis loss of NO at magnetostriction of zero would be larger than that of GO because of the difference in texture.

Tada, Hirotoshi; Fujimura, Hiroshi; Yashiki, Hiroyoshi

2013-01-01

132

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

133

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

134

Adaptive control with hysteresis estimation and compensation using RFNN for piezo-actuator  

Microsoft Academic Search

Because the control performance of a piezoactuator is always severely deteriorated due to hysteresis effect, an adaptive control with hysteresis estimation and compensation using recurrent fuzzy neural network (RFNN) is proposed in this study to improve the control performance of the piezo-actuator. A new hysteresis model by modifying and parameterizing the hysteresis friction model is proposed. Then, the overall dynamics

Faa-Jeng Lin; Hsin-Jang Shieh; Po-Kai Huang; Li-Tao Teng

2006-01-01

135

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

PubMed

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

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

2014-05-28

136

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.

137

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

138

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

139

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

140

Real-time inverse hysteresis compensation of piezoelectric actuators with a modified Prandtl-Ishlinskii model.  

PubMed

This paper presents a novel real-time inverse hysteresis compensation method for piezoelectric actuators exhibiting asymmetric hysteresis effect. The proposed method directly utilizes a modified Prandtl-Ishlinskii hysteresis model to characterize the inverse hysteresis effect of piezoelectric actuators. The hysteresis model is then cascaded in the feedforward path for hysteresis cancellation. It avoids the complex and difficult mathematical procedure for constructing an inversion of the hysteresis model. For the purpose of validation, an experimental platform is established. To identify the model parameters, an adaptive particle swarm optimization algorithm is adopted. Based on the identified model parameters, a real-time feedforward controller is implemented for fast hysteresis compensation. Finally, tests are conducted with various kinds of trajectories. The experimental results show that the tracking errors caused by the hysteresis effect are reduced by about 90%, which clearly demonstrates the effectiveness of the proposed inverse compensation method with the modified Prandtl-Ishlinskii model. PMID:22755661

Gu, Guo-Ying; Yang, Mei-Ju; Zhu, Li-Min

2012-06-01

141

Completely inverted hysteresis loops: Inhomogeneity effects or experimental artifacts  

NASA Astrophysics Data System (ADS)

Completely inverted hysteresis loops (IHL) are obtained by the superconducting quantum interference device with large cooling fields (>10 kOe) in (La,Sr)MnO3 films with self-assembled LaSrMnO4, 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)MnO3/LaSrMnO4, 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.; Cui, B.; Yu, H. Y.; Pan, F.

2013-11-01

142

Dynamic Hysteresis in Cyclic Deformation of Crystalline Solids  

NASA Astrophysics Data System (ADS)

The hysteresis or internal friction in the deformation of crystalline solids stressed cyclically is studied from the viewpoint of collective dislocation dynamics. Stress-controlled simulations of a dislocation dynamics model at various loading frequencies and amplitudes are performed to study the stress-strain rate hysteresis. The hysteresis loop areas exhibit a maximum at a characteristic frequency and a power law frequency dependence in the low frequency limit, with the power law exponent exhibiting two regimes, corresponding to the jammed and the yielding or moving phases of the system, respectively. The first of these phases of the system exhibits nontrivial critical-like viscoelastic dynamics, crossing over to intermittent viscoplastic deformation for higher stress amplitudes.

Laurson, Lasse; Alava, Mikko J.

2012-10-01

143

Hysteresis of Freedericksz transition in confined light beams  

SciTech Connect

The effect of the transverse confinement of an incident light beam on the hysteresis of light-induced Freedericksz transition in a nematic liquid crystal cell is considered. The thresholds of the orientational instability of the director with an increase and decrease in the light beam's intensity are calculated numerically in relation to its transverse size. The hysteresis loop width is shown to change nonmonotonically with an increase in the transverse dimension. In contrast to a homogeneous light beam, the hysteresis existence region is determined not only by the parameter (K{sub 3} - K{sub 1})/K{sub 3} but also by the parameter K{sub 2}/K{sub 3}. With an increase in the transverse beam size, the critical values of the parameter (K{sub 3} - K{sub 1})/K{sub 3} increase, while those of the parameter K{sub 2}/K{sub 3} decrease.

Ledney, M. F., E-mail: ledney@univ.kiev.ua; Tarnavsky, A. S. [Kyiv National Taras Shevchenko University (Ukraine)

2010-03-15

144

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

145

Direct recursive identification of the Preisach hysteresis density function  

NASA Astrophysics Data System (ADS)

In this paper, a novel direct method of recursive identification of the Preisach hysteresis density function is proposed. Using the discrete dynamic Preisach model, which is a state-space realization of the classical scalar Preisach model, the method is designed based on the output increment error. After giving the general formulation, the identification scheme implemented for a discretized Preisach plane is introduced and evaluated through the use of numerical simulations. Two cases of Gaussian mixtures are considered for mapping the hysteresis system to be identified. The parameter convergence is shown for a low-pass filtered white-noise input. Further, the proposed identification method is applied to a magnetism-related application example, where the flux linkage hysteresis of a proportional solenoid is assumed from the measurements, and then the inverse of a standard demagnetization procedure is utilized as the identification sequence.

Ruderman, Michael

2013-12-01

146

Very low hysteresis organic thin-film transistors  

NASA Astrophysics Data System (ADS)

Very low hysteresis vanadyl-phthalocyanine/para-sexiphenyl thin-film transistors (TFTs) have been fabricated using benzocyclobutenone (BCBO) derivatives/tantalum pentoxide (Ta2O5)/BCBO triple gate dielectrics. The field effect mobility, on/off current ratio and threshold voltage of organic TFTs are 0.45 cm2 V-1 s-1, 3.5 × 104 and -6.8 V, respectively. To clarify the mechanism of hysteresis, devices with different dielectrics have been studied. It is found that the bottom BCBO derivatives (contact with a gate electrode) block the electron injection from a gate electrode to dielectrics. The top BCBO derivatives are also found to improve the properties of interface between the dielectrics and organic semiconductor. Then very low hysteresis devices are obtained.

Li, Chunhong; Pan, Feng; Zhu, Feng; Song, De; Wang, He; Yan, Donghang

2009-08-01

147

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

148

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

149

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

150

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.

2013-01-01

151

Modelling eddy currents and hysteresis in a transformer laminate  

SciTech Connect

A Cauer circuit model of a transformer laminate is presented. It considers saturation, eddy currents and hysteresis. The simulation results agree to experiments with an Epstein frame in the 10--200 Hz range. The paper includes a description of a computationally fast hysteresis model with few adjustable parameters and a physical approach to derive the Cauer circuit. The model can be used under various time-transient conditions and can easily be implemented into a larger system in a circuit simulation package, such as Saber, to study a transformer`s interaction with switching overvoltages, for example.

Holmberg, P.; Bergqvist, A. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Electric Power Engineering] [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Electric Power Engineering; Engdahl, G. [ABB Corporate Research, Vaesteraas (Sweden). Dept. of Power Engineering] [ABB Corporate Research, Vaesteraas (Sweden). Dept. of Power Engineering

1997-03-01

152

Domain Nucleation and Hysteresis Loop Shape in Piezoresponse Force Spectroscopy  

SciTech Connect

Electromechanical hysteresis loop measurements in piezoresponse force microscopy (PFM) [piezoresponse force spectroscopy (PFS)] have emerged as a powerful technique for probing ferroelectric switching behavior on the nanoscale. Interpretation of PFS data requires the relationship between the domain parameters and PFM signal to be established. Here, the authors analyze the switching process using modified point charge model. The charge parameters are selected to reproduce tip-induced surface potential and tip radius of curvature. The relationship between geometric parameters of semiellipsoidal domain and PFM signal is derived using linear Green's function theory. The role of domain nucleation on hysteresis loop is established.

Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Kalinin, Sergei V [ORNL

2006-01-01

153

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

154

Hysteresis in Analytical Solutions for Three-phase Flow  

NASA Astrophysics Data System (ADS)

Hysteresis in relative permeability is a widely-recognized phenomenon that impacts oil recovery in water and gas (WAG) injection. Several authors (1-3) have constructed analytical solutions for two-phase oil/water or gas/water flow in enhanced oil recovery however, analytical solutions have not previously been constructed for the three-phase flow problem for immiscible water, oil and gas including hysteresis. In this work analytical solutions are constructed for water and gas floods in a previously water-flooded oil reservoir with and without hysteresis. A simplified model is used in the analysis that qualitatively captures the behavior of oil-phase hysteresis for repeated water imbibition and drainage cycles. Many of the displacements considered have a reversal of flow direction within the displacement, requiring a matching condition to be enforced between the imbibition and drainage relative permeability curves at the point of flow reversal. A suitable matching criterion for the hysteretic curves is presented. A single water/gas injection mixture is considered, with varying initial oil and water volumes present in the reservoir. When hysteresis occurs in a displacement the entire saturation path depends on the initial volumes of oil and water present at the onset of WAG flooding. When hysteresis is ignored most of the displacement is identical for a large range of initial oil and water mixtures, with only the velocity of the leading shock changing. For the displacements which only encounter drainage of the water phase, solutions with and without hysteresis are identical. 1) K. M. Furati, ``Effects of Relative Permeability History Dependence on Two-Phase Flow in Porous Media,'' Transport in Porous Media 28: 181-203, 1997. 2) B. Plohr, D. Marchesin, P. Bedrikovetsky and P. Krause, ``Modeling hysteresis in porous media flow via relaxation,'' Computational Geosciences 5: 225-256, 2001. 3) F. M. Van Kats and C. J. Van Duijn, ``A Mathematical Model for Hysteretic Two-Phase Flow in Porous Media,'' Transport in Porous Media 43: 239-263, 2001.

Lambers, J. V.; LaForce, T.

2011-12-01

155

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

156

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

157

Dielectric Hysteresis Loop in Alicyclic and Aromatic Polyamides  

NASA Astrophysics Data System (ADS)

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

Murata, Yukinobu; Tsunashima, Kenji; Koizumi, Naokazu

1994-03-01

158

A dead-beat adaptive hysteresis current control  

Microsoft Academic Search

This paper proposes a new digital algorithm for the implementation of the fixed-frequency adaptive hysteresis current control for voltage-source inverters. The key features of the new algorithm are the minimization of the analog external circuitry, the capability to automatically compensate for the inverter deadtime effects without appreciable delay and a tight synchronization of the inverter voltage pulses with an external

Simone Buso; Sandro Fasolo; Luigi Malesani; Paolo Mattavelli

2000-01-01

159

Hysteresis in a simple model of currency substitution  

Microsoft Academic Search

A cash-in-advance model in which the cost of buying goods with a foreign currency is decreasing in the economy's accumulated experience in transacting in the foreign currency is shown to display hysteresis in money velocity; that is, a temporary increase in expected inflation can cause a permanent increase in velocity. In addition, the model implies that the domestic currency does

Martîn Uribe

1997-01-01

160

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

161

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

162

Fourier analysis of digital hysteresis data: rock magnetic applications  

Microsoft Academic Search

The approach to saturation of a ferromagnetic material can be characterized in terms of the frequency content of its hysteresis loop. This is done by `unfolding' the loop into a pseudo-waveform, which is then analyzed using standard Fourier methods. In experiments on samples with discrete grain sizes of magnetite, the decay of Fourier component amplitude as a function of harmonic

Mike Jackson; Horst-Ulrich Worm; Subir K. Banerjee

1990-01-01

163

Probabilistic counter updates for predictor hysteresis and stratification  

Microsoft Academic Search

Hardware counters are a fundamental building block of modern high-performance processors. This paper ex- plores two applications of probabilistic counter updates, in which the output of a pseudo-random number generator de- cides whether to perform a counter increment or decrement. First, we discuss a probabilistic implementation of counter hysteresis, whereby previously proposed branch confidence and criticality predictors can be reduced

Nicholas Riley; Craig B. Zilles

2006-01-01

164

Dynamic Contact Angles and Hysteresis under Electrowetting-on-Dielectric  

PubMed Central

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

Nelson, Wyatt C.; Sen, Prosenjit; Kim, Chang-Jin "CJ"

2011-01-01

165

Differential hysteresis modeling of a shape memory alloy wire actuator  

Microsoft Academic Search

In this paper, we develop a complete mathematical model of a shape memory alloy (SMA) wire actuated by an electric current and a bias spring. The operation of the SMA actuator involves different physical phenomena, such as heat transfer, phase transformation with temperature hysteresis, stress-strain variations and electrical resistance variation accompanying the phase transformation. We model each of these phenomena

Sushant M. Dutta; Fathi H. Ghorbel

2005-01-01

166

An Accurate Hysteresis Model for Ferroresonance Analysis of a Transformer  

Microsoft Academic Search

This paper introduces an accurate transformer core model, using the Preisach theory, to represent the core magnetization characteristic. This modeling approach provides the required precision to match major and minor hysteresis loops of the model with those of the actual transformer core material. Using the proposed model, the ferroresonance phenomenon of a voltage transformer (VT) is simulated and compared to

Afshin Rezaei-Zare; Reza Iravani; Majid Sanaye-Pasand; Hossein Mohseni; Shahrokh Farhangi

2008-01-01

167

Hysteresis in a swirling jet as a model tornado  

Microsoft Academic Search

A swirling jet, emerging normal to a plane, serves as a model of a tornado and is characterized by its flow force and outer circulation. This model is examined here using the full Navier-Stokes equations. Three branches of solutions are found which form a hysteresis loop and a cusp catastrophe that means jump transitions between flow regimes. One of the

V. Shtern; F. Hussain

1993-01-01

168

Iterative feedforward compensation of hysteresis in piezo positioners  

Microsoft Academic Search

In this article, we prove convergence of an iterative control algorithm to find an input that achieves precise positioning in hysteretic systems. In the analysis, the Preisach hysteresis model is used to characterize the nonlinear behavior of the piezo positioner. We quantify the number of iterations required to achieve a prescribed precision. The method is applied to an experimental piezo

Kam K. Leang; S. Devasia

2003-01-01

169

Novel Hysteresis Current Controller for Active Power Filter  

Microsoft Academic Search

The switching losses of Active Power Filter (APF) is one of the important factors that influence the performance-price ratio of APF. In this paper, a novel method is suggested. Under this new method, each phase output reference current of APF is compared to adjust hysteresis of each phase, so that the switching number of the phase that has greater switching

Zeng Jiang; Liu Yan; Ouyang Sen; Zhen Zaitian

2010-01-01

170

Hysteresis heating based induction bonding of composite materials  

Microsoft Academic Search

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

Witchuda Suwanwatana

2004-01-01

171

Magnetic Hysteresis Damping of Satellite Attitude Motion, Volume I.  

National Technical Information Service (NTIS)

The attitude dynamics of a gravity-gradient oriented satellite, which employs soft nickel-iron rods as magnetic hysteresis dampers, is simulated by a digital computer program. A subroutine was generated to compute the flux induced in the rods for an arbit...

1964-01-01

172

Tracking Control of Piezoelectric Actuators by Feedforward Hysteresis Compensation  

Microsoft Academic Search

Due to the inherent hysteresis nonlinearity, the piezoelectric actuator always causes positioning error in the open-loop operation and instability in the closed-loop operation. In order to improve the positioning accuracy and response speed, a control method for piezoelectric actuator based on a PID feedback controller with a feedforward compensation is proposed. The feedforward controller based on a new mathematical model

Changhai Ru; Bohui Pang; Kejun Wang; Xiufen Ye

2006-01-01

173

Investigation of the Temperature Hysteresis Phenomenon of a Loop Heat Pipe.  

National Technical Information Service (NTIS)

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 ...

T. Kaya J. Ku T. Hoang M. K. Cheung

1999-01-01

174

Magnetic hysteresis dynamics of thin Co films on Cu(001)  

NASA Astrophysics Data System (ADS)

Hysteresis properties of ultrathin (2-4 monolayers) epitaxial Co films grown on Cu(001) surfaces are studied as a function of film thickness, temperature and the strength (H0), in-plane direction, and frequency (?) of applied sinusoidal magnetic field. Scaling of the hysteresis loop area (power loss) of the form A=A0+H?0???(H,?) where ? is a scaling function is explored. All films exhibit a threshold field (Ht) where switching between equivalent magnetized states is initiated. Hysteresis loop areas measured over five decades in frequency exhibit very weak power-law dependence (?~0.02). No evidence of a dynamic phase transition is observed and no indication of a low-frequency (?0~102 Hz) characteristic resonance is apparent over the drive frequency range covered. The observed weak power-law scaling does not support results of prior experiments that have been interpreted as corroborating the mean-field Ising model (?=?=23) and continuum spin models of thin-film hysteresis energy-loss scaling. The measured frequency and applied field-dependent scaling of the dynamic coercive force (H*c) also appears to be inconsistent with recent phenomenological models of hysteresis behavior based on domain-wall motion that predict that H*c scales as ln H?. The results of this study of Co on Cu(001) and a corresponding study of Fe on W(110) suggest that the dynamics of magnetization reversal in real ultrathin film systems do not exhibit universal behavior in the low-field low-frequency limit. Recent theoretical results based on a more realistic model that accounts for thermal noise and spatial fluctuations in the dynamics yield logarithmic scaling at low ? and effective exponents ? that are compatible with the experiments. A simple physical picture of low drive-frequency energy-loss scaling is described that accounts for the experimental observations.

Suen, Jih-Shin; Lee, M. H.; Teeter, G.; Erskine, J. L.

1999-02-01

175

Major hysteresis loop modeling of two-dimensional arrays of single domain particles  

Microsoft Academic Search

We have studied the effect of magnetostatic interactions on the overall shape of hysteresis loops for arrays of single domain particles. A computational model was used to calculate major hysteresis loops of arrays of particles with an easy axis along the applied field. The shear of the hysteresis loop, and consequent loss of squareness, is found to increase both with

M. Hwang; M. Farhoud; Y. Hao; M. Walsh; T. A. Savas; Henry I. Smith; C. A. Ross

2000-01-01

176

A method for the determination of the parameters of the hysteresis model of magnetic materials  

Microsoft Academic Search

Many methods have been proposed for the determination of the hysteresis loops of magnetic materials, and many mathematical approaches have been proposed to find a good model for the hysteresis phenomenon. However, very few attempts have been made to determine the parameters of the hysteresis model experimentally. This paper shows how, starting from a digital method for the experimental determination

L. D'Alessandro; A. Ferrero

1994-01-01

177

Numerical characterization of dynamic hysteresis loops and losses in soft magnetic materials  

Microsoft Academic Search

This paper deals with the characterization of dynamic loops shapes and losses in soft magnetic materials. An experimental and theoretical analysis has been done in order to describe static and dynamic hysteresis on soft ferrite cores. A parallelogram-loop-based hysteresis modeling is described and discussed. The possibility of the model to include vector hysteresis and the related properties are then discussed,

E. Cardeffi; Romano Giannetti; Bernardo Tellini

2005-01-01

178

Reduction of major and minor hysteresis loops in a piezoelectric actuator  

Microsoft Academic Search

This paper addresses the compensation of major and minor hysteresis loops using an operator termed a phaser, which shifts the phase of a periodic signal by an amount ?. For periodic inputs, hysteresis can be approximated by a phaser with a negative phase shift opening the possibility of cascade compensation. Since in actual hysteresis the phase shift varies according to

Juan Manuel Cruz-hernández; Vincent Hayward

1998-01-01

179

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

Microsoft Academic Search

An adaptive wavelet neural network (AWNN) control with hysteresis estimation is proposed in this study to improve the control performance of a piezo-positioning mechanism, which is always severely deteriorated due to hysteresis effect. First, the control system configuration of the piezo-positioning mechanism is introduced. Then, a new hysteretic model by integrating a modified hysteresis friction force function is proposed to

Faa-jeng Lin; Hsin-jang Shieh; Po-kai Huang

2006-01-01

180

Three-level inverter based shunt active power filter using generalized hysteresis current control method  

Microsoft Academic Search

This paper proposes a generalized hysteresis current controlled three level voltage source inverter (VSI) based single phase shunt active power filter (SAPF). The three level inverter topologies considered in this paper are H-bridge and diode clamped inverters. A generalized hysteresis current control with multiband hysteresis modulation has been used to control the voltage source inverters in the shunt active power

Shweta Gautam; Rajesh Gupta

2010-01-01

181

Identification and simulation of a circuit-based model of magnetic hysteresis  

Microsoft Academic Search

Purpose – The scope of the work is to provide an identification procedure for an hysteresis model based on nonlinear circuit cells. Design\\/methodology\\/approach – An identification procedure for an hysteresis model based on nonlinear circuit cells is presented. The response of elementary cell is equal to a generalized play operator. The procedure allows the identification of the limit symmetric hysteresis

G. Gruosso; M. Repetto

2005-01-01

182

Temperature dependence on the hysteresis of aSi:H TFT and Elimination of the hysteresis effect on OLED current for AMOLED Display  

Microsoft Academic Search

The temperature dependence on the hysteresis of a-Si:H TFT has been investigated. We have also proposed and fabricated a new a-Si:H TFT pixel driving scheme, which can eliminate OLED current error caused by the hysteresis of a-Si:H TFT. At an elevated temperature from 25oC to 60oC, the VTH variation of a- Si:H TFT caused by hysteresis was decreased from 0.41V

Sang-Geun Park; Jae-Hoon Lee; Won-Kyu Lee; Min-Koo Han

183

Hysteresis heating based induction bonding of composite materials  

NASA Astrophysics Data System (ADS)

The viability of using magnetic particulate susceptor materials for induction heating during bonding of polymer matrix composites is well established in this work. The unique ability to offer localized heating, geometric flexibility, and self-controlled temperature is the major advantage of this technique. Hysteresis heating is tailored through careful design of the microstructure of nickel particulate polymer films (Ni/PSU). An excellent heating rate can be attained in the frequency range of 1 to 10 MHz for particle volume fraction below percolation of 0.26. The diameter of nickel particle should be kept between 65 nm to 10 mum to ensure multi-domain heating, Curie temperature control, negligible shielding effect, minimum eddy current, and slight particle oxidation. The hysteresis heating behavior of the Ni/PSU films is found to be volumetric in nature and proportional to the cube of applied magnetic field. On the other hand, heat generation is inversely proportional to the size of the multi-domain particles. The frequency effect; however, provide maximum heat generation at the domain wall resonance frequency. Curie temperature control is observed when sufficiently high magnetic fields (˜138 Oe) are applied. The master curves of AC heat generation in Ni/PSU films are established and show a strong particle size effect. Hysteresis fusion bonding of glass/polyphenylene sulfide thermoplastic composites using a magnetic film as the thermoplastic adhesive shows that the bond strength of hysteresis-welded materials is comparable to that of autoclave-welded materials while offering an order of magnitude reduction in cycle time. The relative contribution of the intimate contact and healing mechanisms to the fusion bonding process indicates that hysteresis bonding is controlled by intimate contact. The macroscopic failure modes vary from mostly adhesive composite/film (low bond strength) to a combination of adhesive composite/film, cohesive film, cohesive composite and mostly cohesive composite (high bond strength). Inspection of the microscopic failure at the nickel particle/polymer interface in the film indicates quasi-brittle failure mode. The amount of adhesive failure increases with decreasing particle size and increasing particle volume fraction. The XPS peaks confirm nickel oxide in the form of NiO on the failure surface of particle/polymer debonding of hysteresis susceptor film.

Suwanwatana, Witchuda

184

The hysteresis behavior of an Ising nanowire with core/shell morphology: Monte Carlo treatment  

NASA Astrophysics Data System (ADS)

We have used Monte Carlo Simulations (MCS) to study the hysteresis behavior of the magnetic nanowire with core/shell morphology described by the spin {1}/{2} Ising particles in the core and the spin {3}/{2} Ising particles in the surface shell. The hysteresis curves are obtained for different temperatures. We find that the hysteresis loop areas decrease when the temperature increases and the hysteresis loops disappear at certain temperatures. Barkhausen jumps are observed for the ferromagnetic nanowire system. An unusual form of triple hysteresis behaviors is observed for the ferrimagnetic nanowire system. The thermal behaviors of the coercivity and the remanent magnetization are also investigated.

Boughazi, B.; Boughrara, M.; Kerouad, M.

2014-08-01

185

Hysteresis and Kinetic Effects During Liquid-Solid Transitions  

SciTech Connect

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

Streitz, F H; Chau, R

2009-02-17

186

Hysteresis in the Underdamped Driven Frenkel-Kontorova Model  

SciTech Connect

We study a commensurate chain of atoms subject to a periodic substrate potential, damping, and a thermal bath, and driven by an external dc force. In the underdamped case the average system velocity as a function of adiabatically varying force exhibits hysteresis at nonzero temperatures. The hysteresis exists due to the instability of the driven motion of kinks at high velocities. In the force-decreasing process, the system passes through two regimes: the {open_quotes}cavity-mode{close_quotes} regime (a standing wave superimposed on the state of running atoms) and the {open_quotes}traffic-jam{close_quotes} regime, where the mobility is due to kink-antikink pairs, the kinks being bunched into compact groups. {copyright} {ital 1997} {ital The American Physical Society}

Braun, O.M.; Bishop, A.R.; Roeder, J. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Braun, O.M. [Institute of Physics, Ukrainian Academy of Sciences, 46 Science Avenue, UA-252022 Kiev (Ukraine)] [Institute of Physics, Ukrainian Academy of Sciences, 46 Science Avenue, UA-252022 Kiev (Ukraine)

1997-11-01

187

Simple Model Analysis of Hysteresis Phenomenon of Gas Discharge Plasma  

NASA Astrophysics Data System (ADS)

The hysteresis and multiple-steady states of gas discharge plasma are analyzed by a simple model of chemical-reaction system. In our analysis the emergence of multiple-steady states is explained by using a fact that a function describing the energy balance has three different real roots. The condition that the function has three roots depends on the ratio of the bulk energy increase to the surface energy loss of plasma. The criterion of taking place of the jump between two steady states is examined in a similar manner to order-disorder transition. The critical parameter contains the non-thermodynamic variables such as conductivity and surface quantities. Stabilities of three obtained solutions are discussed by using linear analysis of differential equations and we find that a root represents a saddle point and other two roots represent stable points. The first step to explain the hysteresis phenomenon in Ar gas discharge plasma is found.

Matsunaga, Yasushi; Kato, Tomokazu

1997-01-01

188

Hysteresis modeling of synchronous reluctance motor considering PWM input voltage  

NASA Astrophysics Data System (ADS)

This paper deals with the hysteresis characteristics analysis in PWM fed synchronous reluctance motor (SynRM) using a coupled finite element method (FEM) and Preisach's modeling, which is presented to analyze the characteristics under the effect of saturation and hysteresis loss. With regard to the PWM characteristics, a vector control inverter is combined with an analysis tool. Also, a moving mesh technique is used with regard to rotation due to velocity. The focus of this paper is the applied method of Preisach modeling for rotating machines and the characteristics analysis of a SynRM using the proposed method of analysis. For the propriety of proposed method of analysis, TMS320C31 DSP-installed experimental devices are used. And then, computer simulation and experimental result for the i- ? loci, speed, current response, show the propriety of the proposed method. The characteristic analysis is performed in relation to the maximum efficiency condition for a SynRM in simulation and experiment.

Lee, J. H.; Kim, J. C.; Hyun, D. S.

2000-01-01

189

Contact angle hysteresis on textured surfaces with nanowire clusters.  

PubMed

Nanowire arrays with various agglomeration patterns were synthesized by adjusting the solvent evaporation rates. Nanowires with 200 nm diameter and 2-25 microm in length were fabricated from an anodic aluminum oxide (AAO) porous template. Various drying treatments were applied to develop nanostructured surfaces with topological differences. Due to surface tension forces, copper nanowires after thermal and evaporative drying treatments agglomerated into clusters, while supercritical drying technique provided excellent bundled-free and vertically-standing nanowire arrays. Although all dried surfaces exhibited hydrophobic nature, the contact angle hysteresis, or the difference between advancing and receding angles, was found to be larger on those surfaces with bundled nanowire clusters. To explain the difference, the wetted solid fraction on each surface was calculated using the Cassie-Baxter model to show that the hysteresis was contributed by liquid/solid contact area on the textured surfaces. PMID:23763151

Liao, Ying-Chih; Chiang, Cheng-Kun; Lu, Yen-Wen

2013-04-01

190

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

191

Sediment Hysteresis Patterns In Singapore Urban Residential Lined Channels  

Microsoft Academic Search

A study involving Jurong West (JW)(68.7 ha) and Ang Mo Kio (AMK)(34.9 ha) residential catchments in Singapore was conducted to analyse temporal total suspended sediment concentrations (TSS) in lined drainage channels during rain events. 53 and 25 storm events were sampled respectively for JW and AMK. 3 types of hysteresis patterns namely, clockwise, eight shaped and random shaped were identified.

W. Lee

2006-01-01

192

Degradation and capacitance: voltage hysteresis in CdTe devices  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

193

A new paradigm for modelling hysteresis in macroeconomic flows  

NASA Astrophysics Data System (ADS)

Macroeconomic processes are often conceptualised as “flows”, and analogies are drawn with physical flow processes. Most economic processes, however, carry inherent irreversibility, a fact which these analogies neglect. A better metaphor for economic flows is suggested, involving flows through porous media. This new conceptual framework incorporates important features such as irreversibility and heterostasis through the use of hysteresis. A simple example model is derived, which may be used to derive qualitative results.

Cross, R.; McNamara, H.; Pokrovskii, A.; Rachinskii, D.

2008-02-01

194

Resistive hysteresis in BiFeO 3 thin films  

Microsoft Academic Search

Capacitor-like Au\\/BiFeO3\\/SrRuO3 thin film with (111) orientation was grown on the SrTiO3 (111) substrate by radio frequency magnetic sputtering. It shows a resistive switching behavior, where a stable hysteresis in current–voltage curve was well developed by applying an optimum voltage at room temperature, and it reached the saturation at a bias voltage of 8V. The Child's law in Vmax?0 direction

Jiagang Wu; John Wang; Dingquan Xiao; Jianguo Zhu

2011-01-01

195

An analysis of metal fatigue based on hysteresis energy  

Microsoft Academic Search

Halford's plastic-energy concept for lowcycle fatigue is extended to the medium- and high-cycle ranges. The resulting equations are compared with 74 sets of data in the medium- and high-cycle ranges. The difference in stress between theory and experimental data is less than ±5 percent.The plastic-hysteresis-energy analysis for fatigue is shown to be consistent with the octahedral shear-stress theory. In addition,

C. S. Chang; W. T. Pimbley; H. D. Conway

1968-01-01

196

Hysteresis of Two Inequivalent Planar Magnets with Anisotropy  

Microsoft Academic Search

We study the hysteresis loops for two inequivalent planar magnets with equal magnetic moments and perpendicular anisotropy, which interact via the dipole-dipole interaction. We emphasize locating distinct zero net-magnetization states in zero applied field. We consider a wide range of perpendicular anisotropy constants K1 and K_2and dipole interaction strength g. For a wide range of parameter space (K_2\\/K_1, g\\/K_1) and

Benjamin T. King; M. Amin Kayali; Wayne M. Saslow

2004-01-01

197

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

198

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

199

Hysteresis properties of titanomagnetites: Grain-size and compositional dependence  

Microsoft Academic Search

Sized fractions of x = 0.6, 0.4, 0.2 and 0.0 titanomagnetites were studied with a vibration magnetometer. In the course particles (d > 150 mum), no compositional dependence of hysteresis parameters was found. HC was less than 50 Oe, HR\\/HC > 4 and JR\\/JS < 10-2, reflecting multi-domain behaviour. In contrast, fine particles (d ⋍ 0.1 mum) revealed systematic grain-size

R. Day; M. Fuller; V. A. Schmidt

1977-01-01

200

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

201

Congruency-based hysteresis models for transient simulation  

Microsoft Academic Search

We describe a history-dependent (non-Preisach) hysteresis model based on direct use of experimental first-order reversal curves. We propose that any second or higher order reversal curve can be constructed by using internal segments of the first-order reversal curves, and show that particular transplants (segments with required overall dimensions ?H,?B) can always be found in both the B and H directions

Sergey E. Zirka; Yury I. Moroz; Philip Marketos; Anthony J. Moses

2004-01-01

202

Modeling and adaptive inverse control of hysteresis and creep in ionic polymer-metal composite actuators  

NASA Astrophysics Data System (ADS)

Like most smart materials, such as piezoelectric materials and shape memory alloys, ion-exchange polymer-metal composite (IPMC), which is a kind of electroactive polymer material, exhibits the properties of hysteresis and creep. In this paper we explain the hysteresis and creep properties of IPMC, analyze the hysteresis using a discrete Prandtl-lshlinskii model, obtain a creep model of IPMC through modifying the creep model of piezoelectric material and present an inverse model of the hysteresis. For hysteresis and creep properties of IPMC changing with time at different rates, we applied the LMS (least mean square) algorithm to identify the hysteresis parameters online. An offline identification algorithm was used to obtain the creep parameters. An adaptive inverse strategy of control for IPMC actuators was set up on the basis of a superposition model of nonlinear hysteresis and linear creep, and we obtained good simulation and experiment results.

Hao, Lina; Li, Zhi

2010-02-01

203

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

204

Wettability hysteresis and its implications for DNAPL source zone distribution.  

PubMed

Subsurface heterogeneity at sites contaminated with nonaqueous phase liquids (NAPLs) reduces the effectiveness of traditional remediation measures. One cause may be the increased proportion of NAPL that is hydraulically isolated due to capillary trapping in heterogeneously-wetted materials. This study examines the wettability of ten materials, ranging from minerals, such as calcite and dolomite, to carbonaceous materials, such shale and coal, in air and water, NAPL and air, and NAPL and water systems. The wettability differed depending on which phase the solid material was initially immersed in: the less crystalline solids, if initially contacted by water were water-wet, but if initially contacted by NAPL were NAPL-wet. This difference, termed here wettability hysteresis, was observed for a suite of halogenated NAPLs and was independent of equilibration time. The degree of wettability hysteresis was greatest in the NAPL and water systems, with the magnitude of the difference increasing with the carbonaceous materials. Since the degree of capillary trapping in subsurface materials is related to wettability, the phenomenon of wettability hysteresis suggests that system history is a factor that may increase the heterogeneity of NAPL source zones. PMID:18848369

Ryder, Jodi L; Demond, Avery H

2008-11-14

205

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

206

Two opposite hysteresis curves in semiconductors with mobile dopants  

NASA Astrophysics Data System (ADS)

Semiconductors with mobile dopants (SMDs), which are distinct from conventional semiconductors, exhibit hysteretic current-voltage curves. The fundamental feature of this hysteresis curve is that it exhibits two oppositely rotating directions, whose origin is not clarified yet. Here, we investigate microscopic origin of the two types of curves and show that they result from the spatial inhomogeneity of the mobile dopant distribution in the SMD. In particular, we observed an abnormal modulation of the electronic energy band due to mobile dopants; lower (higher) density of dopants near a metal-semiconductor interface lead to higher (lower) conductance, whereas the conventional ionic models predict the reverse behaviors.

Sung Lee, Jae; Buhm Lee, Shin; Kahng, Byungnam; Won Noh, Tae

2013-06-01

207

A study of hysteresis in the K ID -å relation  

Microsoft Academic Search

A photoelastic study of high speed crack propagation in Homalite 100 was conducted to measure hysteresis in the constitutive\\u000a relation forK\\u000a \\u000a ID\\u000a -. The fracture specimen was designed to obtain both crack acceleration and deceleration during a single crack extension.\\u000a Additional loads perpendicular to the crck-propagation path were applied at secondary locations to accentuate the magnitude\\u000a of acceleration-deceleration observed in

J. W. Dally; R. K. Agarwal; R. J. Sanford

1990-01-01

208

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

209

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

210

Reconfiguration and hysteresis in superconducting Nb film with honeycomb arrays  

NASA Astrophysics Data System (ADS)

Superconducting Nb films with honeycomb array of holes are studied using transport measurements. The oscillating magneto-resistance curves are observed up to large flux density. Two types of resistance minima with different field intervals are observed, indicating the reconfiguration of the overall flux lattice from honeycomb to triangular arrangement. Moreover, hysteretic effects are found in a very large field span from H = 2H1 to H = 8.5H1. It is revealed that the hysteresis is related to the presence of interstitial vortices.

He, S. K.; Zhang, W. J.; Wen, Z. C.; Cao, W. H.

2012-12-01

211

Temperature hysteresis of the reflection coefficient of leucosapphire in vacuum  

NASA Astrophysics Data System (ADS)

We have measured the temperature dependences of light reflection of leucosapphire single crystals upon cyclic variation of temperature in the range of 295-155 K. We have revealed an asymmetric temperature hysteresis of specular reflection, which is accompanied by a change in diffuse reflection. It has been found that the behavior of specular reflection is determined by the temperature dependences of the refractive index and topography of the surface. We assume that temperature changes in the reflection are related to structural phase transitions in the superficial layer.

Tsapenko, B. P.; Tsapenko, A. B.; Bondar', V. G.

2014-02-01

212

Anomalous hysteresis properties of iron films deposited on liquid surfaces  

SciTech Connect

A nearly free sustained iron film system, deposited on silicone oil surfaces by vapor-phase deposition method, has been fabricated and its crystal structure as well as magnetic properties has been studied. Both the temperature-dependent coercivity H{sub c}(T) and exchange anisotropy field H{sub E}(T) of the iron films possess a maximum peak around the critical temperature T{sub crit}=10-15 and 4 K, respectively. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase below freezing temperature T{sub f}=30-50 K.

Ye Quanlin; Feng Chunmu; Xu Xiaojun; Jin Jinsheng; Xia Agen; Ye Gaoxiang [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Test and Analysis Center, Zhejiang University, Hangzhou 310028 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China)

2005-07-01

213

Anomalous hysteresis properties of iron films deposited on liquid surfaces  

NASA Astrophysics Data System (ADS)

A nearly free sustained iron film system, deposited on silicone oil surfaces by vapor-phase deposition method, has been fabricated and its crystal structure as well as magnetic properties has been studied. Both the temperature-dependent coercivity Hc(T) and exchange anisotropy field HE(T) of the iron films possess a maximum peak around the critical temperature Tcrit=10-15 and 4 K, respectively. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase below freezing temperature Tf=30-50 K.

Ye, Quan-Lin; Feng, Chun-Mu; Xu, Xiao-Jun; Jin, Jin-Sheng; Xia, A.-Gen; Ye, Gao-Xiang

2005-07-01

214

A dynamic model for hysteresis in magnetostrictive devices  

NASA Astrophysics Data System (ADS)

In this paper, a dynamic model for the description and design of hysteresis in magnetostrictive devices is presented. The model is based on Preisach theory and its dynamic extension. A procedure for determining the Preisach distribution function is given. This procedure is based on neural networks. The model is able to reconstruct both the magnetization relation and the field-strain relation. The model is validated through comparison and prediction of data collected from a typical Terfenol-D sample and a novel experimental technique dedicated to the validation of dynamic models is proposed.

Trapanese, M.; Franzitta, V.; Viola, A.

2014-05-01

215

Reduction of Hysteresis in Organic Field-Effect Transistor by Ferroelectric Gate Dielectric  

Microsoft Academic Search

We studied the reduction of hysteresis in pentacene organic field-effect transistors (OFETs) with a ferroelectric poly(vinylidene fluoride and trifluoroethylene) [P(VDF-TrFE)] dipole layer used as a coating of silicon dioxide gate insulator. Although the OFETs without the dipole layer exhibited a hysteresis caused by carrier trapping, such hysteresis was not observed for the OFETs with the P(VDF-TrFE) layers. Experiments showed that

Xiangyu Chen; Wei Ou-Yang; Martin Weis; Dai Taguchi; Takaaki Manaka; Mitsumasa Iwamoto

2010-01-01

216

A numerical method for analyzing a passive fault current limiter considering hysteresis  

Microsoft Academic Search

Fast transient analysis of a passive fault current limiter (FCL) using permanent magnets can be done by direct numerical solution of a single non-linear differential equation. The non-linear B-H excursion that is caused by hysteresis is incorporated in the computation using a transient hysteresis model. Rational fractions are used to represent the parent hysteresis loop curves. Since the method uses

A. Mukherjee; S. C. Mukhopadhyay; M. Iwahara; S. Yamada; F. P. Dawson

1998-01-01

217

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

SciTech Connect

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

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

2012-01-01

218

Analysis of Power Magnetic Components With Nonlinear Static Hysteresis: Proper Orthogonal Decomposition and Model Reduction  

Microsoft Academic Search

We applied the proper orthogonal decomposition (POD) method to extract reduced-order models to efficiently solve nonlinear electromagnetic problems governed by Maxwell's equations with nonlinear hysteresis at low frequency (10 kHz), called static hysteresis, discretized by a finite-element method. We used a new domain-wall-motion hysteresis model for Power MAgnetic Components (POMACs) in the finite-element potential formulation via an efficient implicit-inverse model

Y. Zhai; L. Vu-Quoc

2007-01-01

219

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

Microsoft Academic Search

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

Y. Zhai; L. Vu-Quoc

2005-01-01

220

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

221

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

222

Transport, hysteresis and avalanches in artificial spin ice systems  

SciTech Connect

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

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

2010-01-01

223

Hysteresis-free operation of suspended carbon nanotube transistors  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes offer high sensitivity and very low power consumption when used as field-effect transistors in nanosensors. Suspending nanotubes between pairs of contacts, rather than attaching them to a surface, has many advantages in chemical, optical or displacement sensing applications, as well as for resonant electromechanical systems. Suspended nanotubes can be integrated into devices after nanotube growth, but contamination caused by the accompanying additional process steps can change device properties. Ultraclean suspended nanotubes can also be grown between existing device contacts, but high growth temperatures limit the choice of metals that can be used as contacts. Moreover, when operated in ambient conditions, devices fabricated by either the post- or pre-growth approach typically exhibit gate hysteresis, which makes device behaviour less reproducible. Here, we report the operation of nanotube transistors in a humid atmosphere without hysteresis. Suspended, individual and ultraclean nanotubes are grown directly between unmetallized device contacts, onto which palladium is then evaporated through self-aligned on-chip shadow masks. This yields pairs of needle-shaped source/drain contacts that have been theoretically shown to allow high nanotube-gate coupling and low gate voltages. This process paves the way for creating ultrasensitive nanosensors based on pristine suspended nanotubes.

Muoth, M.; Helbling, T.; Durrer, L.; Lee, S.-W.; Roman, C.; Hierold, C.

2010-08-01

224

Hysteresis of soft joints embedded with fluid-filled microchannels  

PubMed Central

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.

Ghatak, Animangsu; Majumder, Abhijit; Kumar, Rajendra

2008-01-01

225

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

226

Hysteresis and saturation effects with the ALS lattice magnets  

SciTech Connect

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

Keller, R.

1995-04-01

227

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

228

Hysteresis of the Kuroshio penetrations into the South China Sea  

NASA Astrophysics Data System (ADS)

An idealized problem of a western boundary current of Munk thickness LM flowing across a gap in a ridge is considered using a single-layer depth-averaged approach. When the gap (of width 2 a) is narrow, a <= 3.12 LM, viscous forces alone restrict penetration of the current through the gap. However, the gap is ``leaky'' in the linear case and some very weak flow still passes through. For larger gap width, the boundary current may leap across the gap due to inertia characterized by the Reynolds number Re, completely choking off water exchange between the two basins. For a >= 4.55 LM the flow may be in one of two regimes (penetrating or leaping) for the same parameters depending on previous evolution. The penetrating branch solutions become unsteady with eddies forming west of the gap between the two counter-flowing zonal jets. As the boundary current slowly accelerates, transition from the penetrating to leaping regime happens when the width of a zonal jet near the gap becomes comparable with a, implying the Reynolds number ReP ~= (a/LM)3. On the other hand as the boundary current slowly decelerates, the leaping regime persists while the meridional advection dominates the ? -effect in a wiggle of the current core within the gap, implying that the leaping regime breaks at ReL ~= a/LM. Thus hysteresis occurs over the range of Reynolds numbers ReL < Re < ReP. An interesting application of this problem is to the Kuroshio current in Luzon Strait. The theory suggests that normally the Kuroshio can leap across Luzon Strait (LQP >= a). However, during periods when its strength is substantially reduced, it may penetrate into the South China Sea as a loop current. Thus multiple states and hysteresis are likely to occur. Because of the possible hysteresis, in analyzing the observational data, it is important to correlate the Kuroshio penetrations not only with the parameters describing the present state of the current, but also to take into account its history. For example, Farris and Wimbush (1996) found a relationship between the loop-current stage (derived from satellite infrared images) and the wind-stress history: the Kuroshio penetrations occur when the time-integrated strength of the northeast monsoon exceeds a threshold value. This is in qualitative agreement with the present theory in the sense that the penetrations occur when the Kuroshio is weakened by the monsoon blowing in the opposite direction.

Sheremet, V. A.

2001-12-01

229

Hysteresis compensation of a porous silicon relative humidity sensor using ANN technique  

Microsoft Academic Search

This paper presents a simple technique based on well-known multilayer perceptron (MLP) neural network with back propagation training algorithm for compensating the significant error due to hysteresis in a porous silicon relative humidity sensor. The porous silicon humidity sensor has been fabricated, and its hysteresis with increasing and decreasing relative humidity has been determined experimentally by a novel phase detection

Tariqul Islam; Hiranmay Saha

2006-01-01

230

Hysteresis and nonlinearity compensation of relative humidity sensor using support vector machines  

Microsoft Academic Search

Based on support vector machine (SVM) technique, a novel method for hysteresis and nonlinearity compensation of a relative humidity sensor has been investigated. The compensation method consists of a two-stage procedure. First, a SVM is used to perform the hysteresis error compensation of the sensor. Then, a second SVM is utilized to compensate the nonlinearity error in the response characteristics

Xiaodong Wang; Meiying Ye

2008-01-01

231

Nondestructive characterization of recovery and recrystallization in cold rolled low carbon steel by magnetic hysteresis loops  

Microsoft Academic Search

How structure sensitive parameters derived from hysteresis loops can provide nondestructive information about the evolution of the microstructure of cold rolled low carbon steel as a result of recovery and recrystallization processes during the annealing is shown. The coercive field, remanent induction and hysteresis losses can be used to monitor the decrease in the dislocation density during recovery. These parameters

A. Martínez-de-Guerenu; K. Gurruchaga; F. Arizti

2007-01-01

232

A simple method to determine dynamic hysteresis loops of soft magnetic materials  

Microsoft Academic Search

An approach to plotting hysteresis curves of soft magnetic materials using a personal computer assisted measuring system is presented. The resulting hysteresis curves provide enough detail to allow determination of the parameters required for a simulation with PSPICE (Jiles-Atherton model) or the Hodgdon\\/Carpenter model. The magnetic core loss for different materials and core shapes can be determined at frequencies up

N. Schmidt; H. Guldner

1996-01-01

233

Modeling microstructural effects on hysteresis loops with the same maximum flux density  

Microsoft Academic Search

Microstructural attributes such as grain size d and dislocation density ?d affect the hysteretic magnetic properties of steels because they affect domain wall movement and pinning. In an earlier paper, a model was proposed for computing hysteresis loops based on the effect of grain size and dislocation density. In that paper, hysteresis loops were compared that all had the same

M. J. Sablik; F. J. G. Landgraf

2003-01-01

234

Interpretation of hysteresis loops of cobalt-rare-earth single particles  

Microsoft Academic Search

The magnetic behavior of single particles of Co5Sm is being studied in an effort to understand the origin of the coercive force in cobalt rare earths. It has been found that the complex hysteresis loops often observed, containing several magnetization discontinuities, can be analyzed as the linear sum of single-discontinuity hysteresis loops, implying that regions of a particle can act

J. Becker

1971-01-01

235

Impacts of Transformer Core Hysteresis Formation on Stability Domain of Ferroresonance Modes  

Microsoft Academic Search

This paper investigates impacts of various formations of hysteresis on the stability domain of ferroresonance modes of a voltage transformer (VT). Based on four different hysteretic and two single-valued polynomial models, ferroresonance behaviors of the VT are studied. The hysteretic models are developed based on the Preisach theory. The first hysteretic model accurately duplicates the measured hysteresis loops of the

Afshin Rezaei-Zare; Reza Iravani; Majid Sanaye-Pasand

2009-01-01

236

Phosphorus–discharge hysteresis during storm events along a river catchment: the River Swale, UK  

Microsoft Academic Search

Variations in the concentration of determinands in rivers during storms often result in a hysteresis effect with different concentration during the rising and falling limb of the hydrograph. This is investigated here by measuring total phosphorus, particulate phosphorus and soluble reactive phosphorus at 3-h intervals at three points along the River Swale. Phosphorus concentration–discharge hysteresis from 10 storm events were

Michael J. Bowes; William A. House; Robin A. Hodgkinson; David V. Leach

2005-01-01

237

Modeling plastic deformation effects in steel on hysteresis loops with the same maximum flux density  

Microsoft Academic Search

Plastic deformation affects the hysteretic magnetic properties of steels because it changes the dislocation density, which affects domain-wall movement and pinning, and also because it places the specimen under residual strain. An earlier paper proposed a model for computing hysteresis loops on the basis of the effect of grain size d and dislocation density ?d. In that paper, hysteresis loops

Martin J. Sablik; Taeko Yonamine; Fernando J. G. Landgraf

2004-01-01

238

Large melting point hysteresis of Ge nanocrystals embedded inSiO2  

SciTech Connect

The melting behavior of Ge nanocrystals embedded within SiO{sub 2} is evaluated using in situ transmission electron microscopy. The observed melting point hysteresis is large ({+-} 17%) and nearly symmetric about the bulk melting point. This hysteresis is modeled successfully using classical nucleation theory without the need to invoke epitaxy.

Xu, Q.; Sharp, I.D.; Yuan, C.W.; Yi, D.O.; Liao, C.Y.; Glaeser,A.M.; Minor, A.M.; Beeman, J.W.; Ridgway, M.C.; Kluth, P.; Ager III,J.W.; Chrzan, D.C.; Haller, E.E.

2006-05-04

239

High-speed tracking control of piezoelectric actuators using an ellipse-based hysteresis model.  

PubMed

In this paper, an ellipse-based mathematic model is developed to characterize the rate-dependent hysteresis in piezoelectric actuators. Based on the proposed model, an expanded input space is constructed to describe the multivalued hysteresis function H[u](t) by a multiple input single output (MISO) mapping Gamma:R(2)-->R. Subsequently, the inverse MISO mapping Gamma(-1)(H[u](t),H[u](t);u(t)) is proposed for real-time hysteresis compensation. In controller design, a hybrid control strategy combining a model-based feedforward controller and a proportional integral differential (PID) feedback loop is used for high-accuracy and high-speed tracking control of piezoelectric actuators. The real-time feedforward controller is developed to cancel the rate-dependent hysteresis based on the inverse hysteresis model, while the PID controller is used to compensate for the creep, modeling errors, and parameter uncertainties. Finally, experiments with and without hysteresis compensation are conducted and the experimental results are compared. The experimental results show that the hysteresis compensation in the feedforward path can reduce the hysteresis-caused error by up to 88% and the tracking performance of the hybrid controller is greatly improved in high-speed tracking control applications, e.g., the root-mean-square tracking error is reduced to only 0.34% of the displacement range under the input frequency of 100 Hz. PMID:20815625

Gu, Guoying; Zhu, Limin

2010-08-01

240

High-speed tracking control of piezoelectric actuators using an ellipse-based hysteresis model  

NASA Astrophysics Data System (ADS)

In this paper, an ellipse-based mathematic model is developed to characterize the rate-dependent hysteresis in piezoelectric actuators. Based on the proposed model, an expanded input space is constructed to describe the multivalued hysteresis function H[u](t) by a multiple input single output (MISO) mapping ?:R2-->R. Subsequently, the inverse MISO mapping ?-1(H[u](t),H[u?](t)u(t)) is proposed for real-time hysteresis compensation. In controller design, a hybrid control strategy combining a model-based feedforward controller and a proportional integral differential (PID) feedback loop is used for high-accuracy and high-speed tracking control of piezoelectric actuators. The real-time feedforward controller is developed to cancel the rate-dependent hysteresis based on the inverse hysteresis model, while the PID controller is used to compensate for the creep, modeling errors, and parameter uncertainties. Finally, experiments with and without hysteresis compensation are conducted and the experimental results are compared. The experimental results show that the hysteresis compensation in the feedforward path can reduce the hysteresis-caused error by up to 88% and the tracking performance of the hybrid controller is greatly improved in high-speed tracking control applications, e.g., the root-mean-square tracking error is reduced to only 0.34% of the displacement range under the input frequency of 100 Hz.

Gu, Guoying; Zhu, Limin

2010-08-01

241

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

242

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

Microsoft Academic Search

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 results for the i-? loci show the propriety of the proposed method

Jung Ho Lee; Dong Seek Hyun

1999-01-01

243

Controlling the response of color tunable poly(N-isopropylacrylamide) microgel-based etalons with hysteresis.  

PubMed

We present the hysteresis of the response of the poly(N-isopropylacrylamide)-co-acrylic acid microgel-based etalons to solution temperature and pH changes. We find that the optical hysteresis of the etalon can be controlled using various solution ionic strengths and/or counterions, as well as by varying the microgel's acrylic acid concentration. PMID:23425938

Hu, Liang; Serpe, Michael J

2013-04-01

244

Creasing Instability of Hydrogel Surfaces: Nucleation, Growth Dynamics & Hysteresis  

NASA Astrophysics Data System (ADS)

The free surface of a hydrogel film supported on a rigid substrate will become unstable to formation of sharp folds when placed under sufficiently large compressive swelling stresses. We seek to exploit this mechanical creasing instability to design smart polymer films with reversible stimuli-responsive properties, however many fundamental questions remain about the mechanism and dynamics of crease formation. We have studied the process of crease nucleation and growth, as well as presence of hysteresis in the level of compressive stress at which folds form and disappear using temperature-responsive surface attached hydrogels. To further understand these processes, we have also studied the influence of skin layers coated on the gel surface and defects in the gel. These studies provide important insights into the mechanism of crease formation and how to control the onset and disappearance of creases.

Hayward, Ryan; Yoon, Jinhwan; Kim, Jungwook

2010-03-01

245

Contact Angle Hysteresis of Photo-Responsive Materials  

NASA Astrophysics Data System (ADS)

An atomic force microscope (AFM) is used to measure the meniscus force on individual microspheres coated with photo-responsive materials such as anatase and rutile TiO2, azobenzene, and other doped oxides as they contact and are retracted from an air/water interface. By exposing the coated microspheres to UV light, the contact angle change. The change can be detected by measuring the increase in the meniscus force. Exposure to visible, infrared, or far infrared light -- as the specific material requires - reverses the contact angle change. The measured force-distance curves are fitted to macroscopic wetting theory. From these measurements, the contact angle, the contact angle hysteresis, and the position of the contact line pinning were simultaneously determined. This allowed for a quantification of the contact angle changes from photo-switching.

Rosenthal, Samuel; McGuiggan, Patricia

2013-03-01

246

Theory and simulation of angular hysteresis on planar surfaces.  

PubMed

A simple model is proposed to simulate contact angle hysteresis in drops on a planar surface. The model is based on assuming a friction force acting on the triple contact line in such a way that the contact line keeps fixed for contact angles comprised between the advancing angle and the receding one and is allowed to move in order to avoid angles outside this interval. The model is straightforwardly applied to axisymmetric drops for which a simple solution of the Young-Laplace equation can be obtained. A variation of the method has also been implemented for nonaxisymmetric drops by resorting to the public-domain "Surface Evolver" software. Comparison with experiments shows the excellent performance of the model. PMID:22050087

Santos, M J; White, J A

2011-12-20

247

Dependence of Barkhausen Pattern Reproducibility on Hysteresis Loop Size  

NASA Astrophysics Data System (ADS)

Barkhausen noise from the ferromagnetic alloy Fe_21Co_64B_15 (which shows many statistical properties characteristic of a single-degree-of-freedom model(Durin, Bertotti, and Magni, Fractals 3, 351 (1995))) showed reproducible structure on succesive minor hysteresis loops, as has been found in other materials(Urbach, Madison, and Markert, PRL 75, 276 (1995))^, (Petta, Weissman, and O'Brien, PRE, 54, R1029 (1996)). However, on full loops extending to saturation, we could detect no reproducible structure anywhere in the loop. This indicates that the detailed statistics do not directly reflect the underlying quenched disorder of the material, but rather involve some self-organization of domain walls, capable of following multiple pathways after being reset by saturating fields.

Petta, J. R.; Weissman, M. B.

1997-03-01

248

Hysteresis of glaciations in the Permo-Carboniferous  

NASA Astrophysics Data System (ADS)

hysteresis of glaciations in the Permo-Carboniferous is simulated in an iterative energy balance model with 84 scenarios of varied orbital elements, CO2 levels, and glacial modes. Gondwana attains its glacial maximum when CO2 is roughly the same or slightly higher than the preindustrial level. Once glaciated it maintains a large ice covered area under higher CO2 levels up to 4 to 6 times of the preindustrial value followed by an abrupt disappearance of ice beyond this threshold. The solutions arrived at by iteration indicate the existence of parameter thresholds of glaciations and deglaciations which lead to the alternating extremes of glacial coverage. Dominated by the large seasonal cycle over land, the concentrated geography of the Permo-Carboniferous is more sensitive to the CO2-forced climate than sparsely distributed land. Our conceptual modeling agrees well with the recent geological evidence of intercalations of three glaciations and two lacunae of deglaciations in this geologic time.

Zhuang, Kelin; North, Gerald R.; Giardino, John R.

2014-03-01

249

Hysteresis in flow patterns in annular swirling jets  

SciTech Connect

This study investigates the influence of swirl on the mean cold flowfield of an annular jet with a stepped-conical expansion. Both the axial and azimuthal velocity components are measured using a two component Laser Doppler Anemometry system in forward scattering mode. A detailed description of the radial profiles of both mean axial and azimuthal velocity as well as three components of the Reynolds stress are given. Four different jets are identified as a function of the swirl number: 'Closed Jet Flow', 'Open Jet Flow Low Swirl', 'Open Jet Flow High Swirl' and 'Coanda Jet Flow'. These flow patterns change with varying swirl number and there exists hysteresis when increasing and subsequently decreasing the swirl. Also a method for jet identification based upon pressure measurements is presented to replace the time consuming LDA measurements. (author)

Vanierschot, M.; Van den Bulck, E. [Katholieke Universiteit Leuven, Department of Mechanical Engineering, Division of Applied Mechanics and Energy Conversion, Celestijnenlaan 300A, B-3001 Heverlee (Belgium)

2007-05-15

250

Structure, morphology and melting hysteresis of ion-implanted nanocrystals  

NASA Astrophysics Data System (ADS)

Investigations of nanosized metal and semimetal inclusions produced by ion implantation in aluminium are reviewed. The inclusions are from 1 nm to 15 nm in size and contain from 80 to 100 000 atoms. Embedded crystallites, which are topotactically aligned with the surrounding matrix, may not be produced in this size range by any other method. The inclusions offer unique possibilities for study of the influence of interfaces on the crystal structure of the inclusions as well as on their melting and solidification behaviour. Studies are made with transmission electron microscopy (TEM), electron- and X-ray diffraction and in situ RBS-channeling measurements. Bi, Cd, In, Pb and Tl inclusions all show a substantial melting/solidification temperature hysteresis, which, in all cases except for Bi, is placed around the bulk melting temperature, while bismuth melts below that temperature.

Andersen, Hans Henrik; Johnson, Erik

1995-12-01

251

The thermodynamic origin of hysteresis in insertion batteries.  

PubMed

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 10(10)-10(17) 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. PMID:20383130

Dreyer, Wolfgang; Jamnik, Janko; Guhlke, Clemens; Huth, Robert; Moskon, Joze; Gaberscek, Miran

2010-05-01

252

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

253

Isotropic vector hysteresis modeling with feed-forward neural networks  

NASA Astrophysics Data System (ADS)

A new vector hysteresis model is presented, based on the function approximation capabilities of feed-forward neural networks. Two-dimensional circular and elliptical magnetization of laminated SiFe steel sheets can be successfully handled by the model. A feed-forward neural network with four inputs, derived at each time step from the time-dependent magnetic induction vector, yields an accurate prediction of the magnetic field strength vector. Measurement results for a steel sheet sample are used to train and test the neural network. The model accuracy is good and can be easily adapted to the requirements of the application by extending or reducing the network training set and thus the required amount of measurement data. Besides, the presented technique is fast, requires no large data set, and applies standard neural network algorithms. Future extension of the model to other magnetization patterns is possible.

Makaveev, Dimitre; Dupré, Luc; de Wulf, Marc; Melkebeek, Jan

2002-05-01

254

Hysteresis modeling of sequential application of orthogonal fields  

NASA Astrophysics Data System (ADS)

In a cumulative effort to characterize the sizes, shapes, and distributions of the domains of the structurally superior high strength steels, a characteristic magnetization measurement and a Preisach model are presented to explain and model the distinctive trends observed in the data. The study investigates the effect of a constant transverse magnetic field and a cycling longitudinal magnetic field, applied sequentially, on the major hysteresis loop of solid cylinders of high strength steel. A coupled-hysteron vector Preisach model is extended to model the longitudinal magnetization of the samples under the effect of an applied transverse field. Insights about the microstructure of the rods and the contribution of different domains and magnetization mechanisms to the magnetic response are drawn.

ElBidweihy, H.; Della Torre, E.; Burgy, C. D.

2014-05-01

255

Dynamics and hysteresis in square lattice artificial spin ice  

NASA Astrophysics Data System (ADS)

Dynamical effects under geometrical frustration are considered in a model for artificial spin ice on a square lattice in two dimensions. Each island of the spin ice has a three-component Heisenberg-like dipole moment subject to shape anisotropies that influence its direction. The model has real dynamics, including rotation of the magnetic degrees of freedom, going beyond the Ising-type models of spin ice. The dynamics is studied using a Langevin equation solved via a second-order Heun algorithm. Thermodynamic properties such as the specific heat are presented for different couplings. A peak in specific heat is related to a type of melting-like phase transition present in the model. Hysteresis in an applied magnetic field is calculated for model parameters where the system is able to reach thermodynamic equilibrium.

Wysin, G. M.; Moura-Melo, W. A.; Mól, L. A. S.; Pereira, A. R.

2013-04-01

256

Origin of the constricted hysteresis loop in cobalt ferrites revisited  

NASA Astrophysics Data System (ADS)

A series of Co ferrites (Co xFe 3- xO 4 ( x=0-1)) were prepared using solid-state method in this work. The aging effect of their structures and constrictions of hysteresis loops under low magnetic field were investigated. It was found that during the aging process, the migration of trivalent (bivalent) ions between tetrahedral (A-site) and octahedral (B-site) coordination induced a shrinking of the lattice, which would expand again due to the precipitation of Fe 3+ after a much longer aging time. The first process caused a pronounced constriction of the loops, due to the uniaxial anisotropy led by this migration. The depression of constriction could attribute to both the expansion of lattice and the change of ionic ratios as a result of the second-phase-precipitation. The impacts of Co content, aging time and temperature upon the constriction were also discussed.

Zhang, Hong-guo; Zhang, Yu-Jie; Wang, Weng-Hong; Wu, Guang-Heng

2011-08-01

257

Causes and implications of colloid and microorganism retention hysteresis  

NASA Astrophysics Data System (ADS)

Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1 ?m) and microorganisms (coliphage ?X174 and E. coli D21g) under various transient solution chemistry conditions, and 360 ?m Ottawa sand that was subject to different levels of cleaning, namely, a salt cleaning procedure that removed clay particles, and a salt + acid cleaning procedure that removed clay and reduced microscopic heterogeneities due to metal oxides and surface roughness. Comparison of results from the salt and salt + acid treated sand indicated that microscopic heterogeneity was a major contributor to colloid retention hysteresis. The influence of this heterogeneity increased with IS and decreasing colloid/microbe size on salt treated sand. These trends were not consistent with calculated mean interaction energies (the secondary minima), but could be explained by the size of the electrostatic zone of influence (ZOI) near microscopic heterogeneities. In particular, the depth of local minima in the interaction energy has been predicted to increase with a decrease in the ZOI when the colloid size and/or the Debye length decreased (IS increased). The adhesive interaction was therefore largely irreversible for smaller sized 0.1 ?m CML colloids, whereas it was reversible for larger 1.1 ?m CML colloids. Similarly, the larger E. coli D21g exhibited greater reversibility in retention than ?X174. However, direct comparison of CML colloids and microbes was not possible due to differences in size, shape, and surface properties. Retention and release behavior of CML colloids on salt + acid treated sand was much more consistent with mean interaction energies due to reduction in microscopic heterogeneities.

Bradford, Scott A.; Kim, Hyunjung

2012-09-01

258

Finite element analysis of hysteresis effects in piezoelectric transducers  

NASA Astrophysics Data System (ADS)

The design of ultrasonic transducers for high power applications, e.g. in medical therapy or production engineering, asks for effective computer aided design tools to analyze the occurring nonlinear effects. In this paper the finite-element-boundary-element package CAPA is presented that allows to model different types of electromechanical sensors and actuators. These transducers are based on various physical coupling effects, such as piezoelectricity or magneto- mechanical interactions. Their computer modeling requires the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields as well as coupled mechanical-acoustic fields. With the reported software environment we are able to compute the dynamic behavior of electromechanical sensors and actuators by taking into account geometric nonlinearities, nonlinear wave propagation and ferroelectric as well as magnetic material nonlinearities. After a short introduction to the basic theory of the numerical calculation schemes, two practical examples will demonstrate the applicability of the numerical simulation tool. As a first example an ultrasonic thickness mode transducer consisting of a piezoceramic material used for high power ultrasound production is examined. Due to ferroelectric hysteresis, higher order harmonics can be detected in the actuators input current. Also in case of electrical and mechanical prestressing a resonance frequency shift occurs, caused by ferroelectric hysteresis and nonlinear dependencies of the material coefficients on electric field and mechanical stresses. As a second example, a power ultrasound transducer used in HIFU-therapy (high intensity focused ultrasound) is presented. Due to the compressibility and losses in the propagating fluid a nonlinear shock wave generation can be observed. For both examples a good agreement between numerical simulation and experimental data has been achieved.

Simkovics, Reinhard; Landes, Hermann; Kaltenbacher, Manfred; Hoffelner, Johann; Lerch, Reinhard

2000-06-01

259

A theory of double hysteresis for ferroelectric crystals  

NASA Astrophysics Data System (ADS)

A ferroelectric crystal is known to exhibit the usual single hysteresis below its Curie point TC, but above this temperature its electric displacement D versus electric field E plot tends to form double loops. We first point out that there is a fundamental difference in the formation of double loops from the single one: the single loop is formed solely by polar reorientation, but in the double loops the right branch of its upper loop is formed by phase transition and only the left branch is formed by polar reorientation (the process is reversed for the lower loop). In this study we take the view that both cubic-->tetragonal phase transition and the polar reorientation of ferroelectric domain are thermodynamics-driving process and use this concept to develop a micromechanics-based thermodynamic model to simulate the double hysteresis behavior of the crystal. We first derive the thermodynamic driving force for both spontaneous polarization and domain switch at a given level of temperature, stress, electric field, and new domain concentration c1 and then establish the kinetic equations for domain growth. A dual-phase homogenization theory is then introduced to calculate the overall electric displacement and mechanical strain of the crystal. This approach differs from the classical Landau-Ginzburg-Devonshire theory in at least two significant aspects: (i) it is developed with a micromechanics-based thermodynamics principle, and (ii) it can provide the evolution of new domain concentration. The developed theory is applied to a BaTiO3 crystal. The calculated results show a single loop below its TC and double loops above it but with a diminishing width at higher temperature. Furthermore, the longitudinal strain ? vs E loop is found to exhibit the usual butterfly-shape relation below TC, but above it the loop shows a new, overlapping double-well picture. Good agreement with available test data is also observed.

Srivastava, N.; Weng, G. J.

2006-03-01

260

Causes and implications of colloid and microorganism retention hysteresis.  

PubMed

Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1 ?m) and microorganisms (coliphage ?X174 and E. coli D21g) under various transient solution chemistry conditions, and 360 ?m Ottawa sand that was subject to different levels of cleaning, namely, a salt cleaning procedure that removed clay particles, and a salt+acid cleaning procedure that removed clay and reduced microscopic heterogeneities due to metal oxides and surface roughness. Comparison of results from the salt and salt+acid treated sand indicated that microscopic heterogeneity was a major contributor to colloid retention hysteresis. The influence of this heterogeneity increased with IS and decreasing colloid/microbe size on salt treated sand. These trends were not consistent with calculated mean interaction energies (the secondary minima), but could be explained by the size of the electrostatic zone of influence (ZOI) near microscopic heterogeneities. In particular, the depth of local minima in the interaction energy has been predicted to increase with a decrease in the ZOI when the colloid size and/or the Debye length decreased (IS increased). The adhesive interaction was therefore largely irreversible for smaller sized 0.1 ?m CML colloids, whereas it was reversible for larger 1.1 ?m CML colloids. Similarly, the larger E. coli D21g exhibited greater reversibility in retention than ?X174. However, direct comparison of CML colloids and microbes was not possible due to differences in size, shape, and surface properties. Retention and release behavior of CML colloids on salt+acid treated sand was much more consistent with mean interaction energies due to reduction in microscopic heterogeneities. PMID:22820488

Bradford, Scott A; Kim, Hyunjung

2012-09-01

261

Modeling of quasistatic magnetic hysteresis with feed-forward neural networks  

NASA Astrophysics Data System (ADS)

A modeling technique for rate-independent (quasistatic) scalar magnetic hysteresis is presented, using neural networks. Based on the theory of dynamic systems and the wiping-out and congruency properties of the classical scalar Preisach hysteresis model, the choice of a feed-forward neural network model is motivated. The neural network input parameters at each time step are the corresponding magnetic field strength and memory state, thereby assuring accurate prediction of the change of magnetic induction. For rate-independent hysteresis, the current memory state can be determined by the last extreme magnetic field strength and induction values, kept in memory. The choice of a network training set is motivated and the performance of the network is illustrated for a test set not used during training. Very accurate prediction of both major and minor hysteresis loops is observed, proving that the neural network technique is suitable for hysteresis modeling.

Makaveev, Dimitre; Dupré, Luc; de Wulf, Marc; Melkebeek, Jan

2001-06-01

262

Measurements and modeling of hysteresis in magnetic materials under the action of an orthogonal bias field  

SciTech Connect

The effect of an orthogonal dc bias field on hysteresis in isotropic magnetic materials under the action of an ac exciting field was investigated. The experimental results indicated that the orthogonal field rotated the hysteresis loops on the BH plane and reduced the enclosed area. As a result, the effective permeability, hysteresis loss, coercivity and remanence decreased with increasing orthogonal bias field. By including the orthogonal field in the anhysteretic model equation and incorporating a variable reversibility coefficient, the Jiles-Atherton hysteresis model was extended to describe the behavior of magnetic materials under the action of an orthogonal bias field. Using finite element modeling for evaluating the effective internal orthogonal field, the modeled hysteresis curve showed quantitative agreement with experimental results.

Bi, Y.; Jiles, D.C.

1999-09-01

263

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

264

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

PubMed

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

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

2013-01-01

265

The effect of contact angle hysteresis on droplet motion and collisions on superhydrophobic surfaces  

NASA Astrophysics Data System (ADS)

The effect of varying the contact angle hysteresis of a superhydrophobic surface on the characteristics and dynamics of water droplet motion and their subsequent collision are investigated using a high-speed camera. The surfaces are created by imparting random roughness to Teflon through sanding. With this technique, it is possible to create surfaces with similar advancing contact angles near 150 degrees, but with varying contact angle hysteresis. This talk will focus on a number of interesting experimental observations pertaining to drop dynamics along a surface with uniform hysteresis, drop motion along surfaces with transition zones from one hysteresis to another, and the collision of droplets on surfaces of uniform hysteresis. For single drop studies, gravity is used as the driving force, while the collision studies use pressurized air to propel one drop into the other. For the case of droplet collision, the effect of hysteresis, Weber number, and impact number on the maximum deformation of the drops, and the post-collision dynamics will be discussed. For the single droplet measurements, the resistance to motion will be characterized as well as the transition from rolling to sliding as a function of drop size, inclination angle, and hysteresis. Additionally, we will quantify the effect of surface transitions on the resulting motion, mixing, and deflection of the drops.

Nilsson, Michael; Rothstein, Jonathan

2010-11-01

266

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

PubMed Central

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

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

2013-01-01

267

Magnetic hysteresis and compensation behaviors in spin-1 bilayer Ising model  

NASA Astrophysics Data System (ADS)

The hysteresis and compensation behaviors of spin-1 bilayer Ising model on a square lattice is studied within the framework of the effective-field theory with correlation. The effects of Hamiltonian parameters on hysteresis behaviors are discussed in detail. We also obtained the Q-, R-, P-, S- and L-type compensation behaviors in the system. A number of interesting phenomena such as the shape of the hysteresis loops and compensation types have been found. The obtained results are compared with some experimental and theoretical results and found to be in a qualitatively good agreement.

Kantar, Ersin; Erta?, Mehmet

2014-06-01

268

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

NASA Astrophysics Data System (ADS)

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

Abang, Ada; Webb, David J.

2014-01-01

269

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

NASA Astrophysics Data System (ADS)

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

Bazghaleh, Mohsen; Grainger, Steven; Cazzolato, Ben; Lu, Tien-Fu; Oskouei, Reza

2014-04-01

270

Solute concentration-dependent contact angle hysteresis and evaporation stains.  

PubMed

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

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

2014-07-01

271

Hysteresis and the dynamic phase transition in thin ferromagnetic films  

SciTech Connect

Hysteresis and the nonequilibrium dynamic phase transition in thin magnetic films subject to an oscillatory external field have been studied by Monte Carlo simulation. The model under investigation is a classical Heisenberg spin system with a bilinear exchange anisotropy {Lambda} in a planar thin film geometry with competing surface fields. The film exhibits a nonequilibrium phase transition between dynamically ordered and dynamically disordered phases characterized by a critical temperature T{sub cd}, whose location is determined by the amplitude H{sub 0} and frequency {omega} of the applied oscillatory field. In the presence of competing surface fields the critical temperature of the ferromagnetic-paramagnetic transition for the film is suppressed from the bulk system value T{sub c} to the interface localization-delocalization temperature T{sub ci}. The simulations show that in general T{sub cd}{lt}T{sub ci} for the model film. The profile of the time-dependent layer magnetization across the film shows that the dynamically ordered and dynamically disordered phases coexist within the film for T{lt}T{sub cd}. In the presence of competing surface fields, the dynamically ordered phase is localized at one surface of the film.

Jang, Hyunbum; Grimson, Malcolm J.

2001-06-01

272

Magnetic hysteresis minor loops in Fe single crystal  

NASA Astrophysics Data System (ADS)

Magnetic hysteresis minor loops were measured with step by step increase of the magnetic field amplitude, Ha, in plastically deformed Fe single crystal. In order to analyse minor loops in connection with the lattice defects, we defined some magnetic parameters, such as the pseudo-coercive force, Hc*, and the differential susceptibility under the pseudo-coercive force khgrH*. Hc*, for instance, is the magnetic field where the magnetization becomes zero in minor loops. In this work, we found the relationship 2Hc* = Ha to hold over a fairly wide Ha range. These parameters are important for representing Bloch wall displacement and the potential energy. The parameters are remarkably sensitive to lattice defects in the field range below the coercive force Hc. The relation of 1/khgrH* and Hc* shows better sensitivity—90 times higher than that for Hc—for revealing information on dislocations. In the minor loop measurement, for getting full information on dislocations it is sufficient to have Ha = 400 A m-1.

Takahashi, S.; Zhang, L.; Ueda, T.

2003-11-01

273

Discontinuous Double Power Law Scaling of Magnetic Hysteresis  

NASA Astrophysics Data System (ADS)

Frequency(?), applied field(H), and temperature(T) -dependent hysteresis loops of ultrathin Fe films on flat and stepped W(001) surface are measured using the magneto-optic Kerr effect. Power law scaling of the loop area A ~ H^??^? is observed over five decades in ? with exponents similar to those observed for Fe on W(110)^1. In cases where the dynamic coercivity H_c(?) exceeds the applied field, an abrupt collapse of the loop occurs leading to a double-power-law scaling behavior similar to that reported by Luse and Zangwill^2 based on a periodically driven kinetic Ising model. The exponent ?' describing the abrupt loop collapse above the amplitude dependent critical frequency is very large compared to the low frequency range value ?, and ?' is much more sensitive to film thickness than the low frequency regime ?. Supported by DMR-9623494 ^1 Jih-Shin Suen and J. L. Erskine, Bull. Am. Phys. Soc. 41, B22 7 (1996) (and submitted to PRL) ^2 C. N. Luse and A. Zangwill, Phys. Rev. E50, 224 (1994)

Suen, Jih-Shin; Erskine, J. L.

1997-03-01

274

On growth rate hysteresis and catastrophic crystal growth  

NASA Astrophysics Data System (ADS)

Different crystal growth rates as supersaturation is increasing or decreasing in impure media is a phenomenon called growth rate hysteresis (GRH) that has been observed in varied systems and applications, such as protein crystallization or during biomineralization. We have recently shown that the transient adsorption of impurities onto newly formed active sites for growth (or kinks) is sensitive to the direction and rate of supersaturation variation, thus providing a possible explanation for GRH [6]. In the present contribution, we expand on this concept by deriving the analytical expressions for transient crystal growth based on the energetics of growth hillock formation and kink occupation by impurities. Two types of GRH results are described according to the variation of kink density with supersaturation: for nearly constant density, decreasing or increasing supersaturation induce, respectively, growth promoting or inhibiting effects relative to equilibrium conditions. This is the type of GRH measured by us during the crystallization of egg-white lysozyme. For variable kink density, slight changes in the supersaturation level may induce abrupt variations in the crystal growth rate. Different literature examples of this so-called 'catastrophic' crystal growth are discussed in terms of their fundamental consequences.

Ferreira, Cecília; Rocha, Fernando A.; Damas, Ana M.; Martins, Pedro M.

2013-04-01

275

Hysteresis in a swirling jet as a model tornado  

NASA Astrophysics Data System (ADS)

A swirling jet, emerging normal to a plane, serves as a model of a tornado and is characterized by its flow force and outer circulation. This model is examined here using the full Navier-Stokes equations. Three branches of solutions are found which form a hysteresis loop and a cusp catastrophe that means jump transitions between flow regimes. One of the jumps relates to vortex breakdown and the other relates to a new (opposite) effect: abrupt vortex consolidation. These results are compared with those of Long (1961), who considered a near-axis jet in the boundary layer approximation. More detailed analysis made here for high circulation values allows discovery of two new types of asymptotic solutions corresponding to a near-plane fan jet and a two-cell flow. It was also found that the boundary layer approach for the near-axis jet fails to accurately yield the total flow force because the outer flow contributes a share of the momentum flux of comparable magnitude to that of the inner flow. The prediction of the jump transitions between one- and two-cell flow patterns agrees with observations of abrupt changes in tornado patterns in nature.

Shtern, V.; Hussain, F.

1993-09-01

276

Droplet evaporation dynamics on a superhydrophobic surface with negligible hysteresis.  

PubMed

We report on experiments of droplet evaporation on a structured superhydrophobic surface that displays very high contact angle (CA ? 160 deg), and negligible contact angle hysteresis (<1 deg). The droplet evaporation is observed to occur in a constant-contact-angle mode, with contact radius shrinking for almost the entire duration of evaporation. Experiments conducted on Teflon-coated smooth surface (CA ? 120 deg) as a baseline also support an evaporation process that is dominated by a constant-contact-angle mode. The experimental results are compared with an isothermal diffusion model for droplet evaporation from the literature. Good agreement is observed for the Teflon-coated smooth surface between the analytical expression and experimental results in terms of the total time for evaporation, transient volume, contact angle, and contact radius. However, for the structured superhydrophobic surface, the experiments indicate that the time taken for complete evaporation of the droplet is greater than the predicted time, across all droplet volumes. This disparity is attributed primarily to the evaporative cooling at the droplet interface due to the high aspect ratio of the droplet and also the lower effective thermal conductivity of the substrate due to the presence of air gaps. This hypothesis is verified by numerically evaluating the temperature distribution along the droplet interface. We propose a generalized relation for predicting the instantaneous volume of droplets with initial CA > 90 deg, irrespective of the mode of evaporation. PMID:23952149

Dash, Susmita; Garimella, Suresh V

2013-08-27

277

Three-dimensional hysteresis of soft magnetic composite  

NASA Astrophysics Data System (ADS)

Hysteresis phenomenon is one of the important characteristics of soft magnetic materials. A three-dimensional (3D) magnetic property measurement system has been developed. This system can effectively control the locus of the time-varying magnetic flux density vector B and measure the corresponding magnetic field strength vector H in a cubic sample of soft magnetic material. The sample involved in this study is a soft magnetic composite sample made of highly pure iron powder. This paper investigates the B and H loci in 3D space and the power loss when the B loci are controlled to become circles and ellipses lying in three orthogonal planes. It is found that the B and H loci lie in the same magnetization plane, but the H loci and losses depend strongly on the orientation, position, and process of magnetization. On the other hand, the H vectors evolve into a unique locus pattern, and the power losses approach a unique value when the B vectors evolve into the same loci through either a series of small circles or ellipses.

Lin, Z. W.; Zhu, J. G.; Guo, Y. G.; Wang, X. L.; Ding, S. Y.

2006-04-01

278

The Near Elimination of Hysteresis in Pd/Cr2O3 Composites  

SciTech Connect

Although its value varies with the microstructure, hysteresis always accompanies hydride formation and decomposition in Pd(pure)-H, e.g., it is present even in nano-crystalline and thin films. Internal oxidation of Pd0.93Cr0.07 alloys leads to a pure Pd matrix containing nano-crystalline chromia precipitates. The characteristic hysteresis of Pd-H almost disappears in this form of Pd. The reasons for this are discussed. Hysteresis is an almost universal feature of first order solid state transitions. Its presence means that when such a transition is reversed, it follows a different path than that taken in the forward direction leading to a loss of useful work. Hysteresis is, of course, a reflection of the irreversibility of the transition.

SHANAHAN, KIRKL

2004-07-14

279

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

National Technical Information Service (NTIS)

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 confi...

J. Alam L. Berke P. L. N. Murthy

1993-01-01

280

Simulation study of hysteresis of argon adsorption in a conical pore and a constricted cylindrical pore.  

PubMed

We present a detailed simulation study of the hysteresis loop in conical pores and in cylindrical pores with periodic constrictions to understand how the non-uniformity of the pore diameter along the pore axis would affect the hysteresis loop. The shape and size of the loop in the conical pores (with and without closed ends) are modified by the cone angle because of the change in the curvature of the menisci at the pore ends. In periodically constricted cylindrical pores, the shape and size of the hysteresis loop are not significantly altered by the pore length or by the presence of a closed end because condensation and evaporation in this type of pore occur in the individual pore sections. Similar hysteresis loops have been found in experimental studies, suggesting that structures of the type modelled here occur in real materials. PMID:23403112

Nguyen, Phuong T M; Do, D D; Nicholson, D

2013-04-15

281

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

282

Magnetic hysteresis curve influenced by power-semiconductor characteristics in pulse-width-modulation inverter  

NASA Astrophysics Data System (ADS)

The influence of power semiconductor characteristic in Pulse-width-modulation (PWM) inverter on the magnetic hysteresis curve in silicon steel is discussed through the measured magnetic hysteresis curves. The magnetic hysteresis curve of PWM inverter-fed silicon steel has a lot of minor loops as closed loops and open loops, which make an influence on the iron loss. Two shapes of minor loops are found to be caused by the voltage shifts and they are derived from the on-voltage of the semiconductors in PWM inverter circuit. Therefore, it is concluded that the power-semiconductor characteristic in PWM inverter makes an influence on the magnetic hysteresis curve in silicon steel.

Fujisaki, Keisuke; Liu, Sungju

2014-05-01

283

Amplitude-Dependent Internal Friction and Harmonic Generation in Media with Hysteresis Nonlinearity and Linear Dissipation  

NASA Astrophysics Data System (ADS)

Based on generalization and integration of models for dislocation mechanisms of the hysteresis nonlinearity, we propose a hysteresis equation of state of polycrystalline solids with saturated amplitude-dependent losses. Using the perturbation method, we study, both theoretically and numerically, the nonlinear effects during propagation of acoustic waves in the media with hysteresis nonlinearity and linear viscous dissipation. Nonlinear damping rate and propagation velocity of the wave at the fundamental frequency, as well as regularities for the amplitudes and phase velocities at its second and third harmonics, are determined. It is shown that the media described by such hysteresis equations of state have a nonlinear dispersion, which leads to a nonmonotonic rise and amplitude beats of the higher harmonics as the wave amplitude increases at the fundamental frequency.

Nazarov, V. E.; Kiyashko, S. B.

2014-03-01

284

Simulation of magnetic hysteresis in pseudo-single-domain grains of magnetite  

Microsoft Academic Search

Magnetic hysteresis has been simulated in grains of magnetite for the size range 0.1-0.7 microns. This was achieved using an unconstrained three-dimensional micromagnetic model of single grains of magnetite with cubic magnetocrystalline anisotropy. Hysteresis loops were obtained for fields applied along both the easy and hard magnetocrystalline axes. Both discrete (Barkhausen) jumps and gradual changes in the magnetic structure are

W. Williams; David J. Dunlop

1995-01-01

285

Pseudo-MOSFET Substrate Effects of Drain Current Hysteresis and Transient Behavior  

Microsoft Academic Search

A large drain current-gate voltage hysteresis of evaporated metal contact pseudo-MOSFETs ( Psi-MOSFET) is reported. The Psi-MOSFET drain current exhibits a hysteresis when the gate voltage is swept from negative to positive and from positive to negative voltages. Optical illumination, elevated temperatures, and decreased sweep rate during the measurements eliminate this phenomenon. The reason for this behavior is related to

Pinakpani Nayak; Sorin Cristoloveanu; Dieter K. Schroder

2009-01-01

286

A hysteresis model for a vanadium dioxide transition-edge microbolometer  

Microsoft Academic Search

This paper presents the adaptation of the Preisach model, originally developed for magnetic hysteresis, to describe mathematically the hysteresis in the resistance-temperature characteristics of vanadium-dioxide (VO2) thin film radiation sensors. The necessary and sufficient conditions for the applicability of the Preisach model to a VO2 film sensor are experimentally verified. Experimentally measured characteristics are compared with those given by the

L. A. L. de Almeida; G. S. Deep; A. M. N. Lima; H. F. Neff; R. C. S. Freire

2001-01-01

287

Experimental and theoretical studies of pressure drop hysteresis in trickle bed reactors  

Microsoft Academic Search

Extensive experimental work was carried out with three different gas-liquid systems (air-water, air-water with surfactant C12H25SO3Na, air-aqueous CMC solution) and three kinds of packings (?2.7, 4.0 and 8.0 mm glass beads) to examine the influence of various parameters on pressure drop hysteresis. Gas and liquid flow rates, physical properties of liquid and operation modes, influence the behavior of hysteresis in

Rong Wang; Zai-Sha Mao; Jiayong Chen

1995-01-01

288

Compensation of hysteresis in magnetic field sensors employing Fiber Bragg Grating and magneto-elastic materials  

Microsoft Academic Search

The paper proposes a novel magnetic field sensor where a technique for hysteresis compensation is employed. The sensor integrates a magnetostrictive material with a Fiber Bragg Grating (FBG) strain sensor. Because of hysteresis and non-linear phenomena taking place in such materials, the sensor’s performances may be sensibly reduced. To this aim, magneto-elastic material is accurately modelled in order to compensate

D. Davino; C. Visone; C. Ambrosino; S. Campopiano; A. Cusano; A. Cutolo

2008-01-01

289

Generating 3-D multi-scroll chaotic attractors: A hysteresis series switching method  

Microsoft Academic Search

Abstract This paper introduces a systematic method—a hysteresis series switching approach—for generating multi-scroll chaotic attractors from a three-dimensional linear autonomous system, including 1-D n-scroll, 2-D n × m-grid scroll, and 3-D n × m × l-grid scroll chaotic attractors. The chaos generation mechanism is studied by analyzing the system trajectories and the hysteresis switching dynamics of the controlled chaotic systems

Jinhu Lu; Fengling Han; Xinghuo Yu; Guanrong Chen

2004-01-01

290

Life prediction of stainless steels by cyclic and stable hysteresis curves  

Microsoft Academic Search

This study develops an analytical expression to describe the cyclic stress?strain curve obtained from a series of fully?reversed fatigue tests. A set of stress?strain relationships is proposed to simulate the tensile branch of the stable hysteresis loop. The complete shape of the stable hysteresis loop is then constructed and the associated theoretical plastic work calculated by integrating the area within

2005-01-01

291

Variation of the hysteresis loop with the Bouc–Wen model parameters  

Microsoft Academic Search

The Bouc–Wen model for smooth hysteresis has received an increasing interest in the last few years due to the ease of its\\u000a numerical implementation and its ability to represent a wide range of hysteresis loop shapes. This model consists of a first-order\\u000a nonlinear differential equation that contains some parameters that can be chosen, using identification procedures, to approximate\\u000a the behavior

Fayçal Ikhouane; Jorge E. Hurtado; José Rodellar

2007-01-01

292

Ac hysteresis loop measurement of stator-tooth in induction motor  

SciTech Connect

The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core loss of the stator tooth can be 50% greater than the core loss under sinusoidal magnetic induction waveform.

Son, D.

1999-09-01

293

Hysteresis loop with controllable shape and direction in an optical ring cavity  

SciTech Connect

We have experimentally observed a 'backward' (clockwise rotating) hysteresis cycle in the system of an optical ring cavity containing three-level ({lambda}-type configuration) rubidium atoms. The shape and direction of the observed hysteresis cycles can be easily controlled with experimental parameters. Such an interesting phenomenon is caused by the greatly modified absorption, dispersion, and nonlinear optical properties of the three-level atomic medium, due to the induced atomic coherence.

Joshi, Amitabh; Yang Wenge; Xiao Min [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

2004-10-01

294

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

Microsoft Academic Search

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

Xiaoyong Zhang; Jun Wang; Chuan Li

2010-01-01

295

Magnetic resonance imaging (MRI) study of jet height hysteresis in packed beds  

NASA Astrophysics Data System (ADS)

The jet-spout transition in fluidized beds can show hysteretic behavior. In this study the jet-spout transition was studied as a function of orifice velocity for particles of different size and shape using Magnetic Resonance Imaging (MRI). The measurements showed that the particle shape primarily affect to the width of the hysteresis loop whereas particle size governs the position of the hysteresis loop with regards to the orifice velocity.

Köhl, Maximilian H.; Lu, Guang; Third, James R.; Prüssmann, Klaas P.; Müller, Christoph R.

2013-06-01

296

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

PubMed

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

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

2014-01-01

297

Hysteresis and multiple pulsing in a semiconductor disk laser with a saturable absorber  

NASA Astrophysics Data System (ADS)

We report on bistable mode-locking in a semiconductor disk laser. The disk laser mode-locked with a semiconductor saturable absorber is investigated for different designs of the gain medium that allow the hysteresis loop to be controlled. Hysteresis formation in the pulsed regime of a semiconductor oscillator with saturable absorption and unsaturated gain is discussed qualitatively. The laser represents an attractive setup for generation and manipulation of dissipative solitons and observation of their interaction.

Saarinen, Esa J.; Lyytikäinen, Jari; Okhotnikov, Oleg G.

2008-07-01

298

Iterative Control Approach to Compensate for Both the Hysteresis and the Dynamics Effects of Piezo Actuators  

Microsoft Academic Search

In this brief, the compensation for both the nonlinear hysteresis and the vibrational dynamics effects of piezo actuators is studied. Piezo actuators are the enabling device in many applications such as atomic force microscopy (AFM) to provide nano- to atomic-levels precision positioning. During high-speed, large-range positioning, however, large positioning errors can be generated due to the combined hysteresis and dynamics

Ying Wu; Qingze Zou

2007-01-01

299

Charge transfer hysteresis in graphene dual-dielectric memory cell structures  

Microsoft Academic Search

We report controlled charge transfer between large-area graphene and a dual-dielectric, silicon nitride\\/silicon oxide substrate. Graphene was grown on copper by chemical vapour deposition, transferred to the nitride substrates, and patterned into test structures. Hysteresis in conductance with varying gate voltage is easily understood in terms of electron transfer between graphene and nitride traps. Increased hysteresis with temperature suggests thermally

S. A. Imam; T. Deshpande; A. Guermoune; M. Siaj; T. Szkopek

2011-01-01

300

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.

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

2014-01-01

301

Mechanical Models of Friction That Exhibit Hysteresis, Stick-Slip, and the Stribeck Effect  

NASA Astrophysics Data System (ADS)

In this dissertation, we model hysteretic and friction phenomena without introducing friction or hysteresis per se. We use a combination of masses, springs, and dashpots and the frictional phenomena emerge as the result of their interaction. By using physical elements, we can understand the physical mechanisms that lead to hysteretic energy dissipation and phenomena, such as stick-slip behavior and the Stribeck effect. Furthermore, we study the origins of butterfly hysteresis, which arises in optics and ferromagnetism. We define the multiplay model for hysteresis with nonlocal memory, which consists of N mass/spring/dashpot with deadzone elements. The advantage of this model is that its hysteresis map can be inverted analytically. Second, we investigate the origins of stick-slip friction by developing an asperity-based friction model involving the frictionless contact between a body and a row of rigid, rotating bristles. This model exhibits hysteresis and quasi-stick-slip friction. The hysteretic energy-dissipation mechanism is the sudden release of the pivoted bristles. The discontinuous rotating bristle model is an approximation of the rotating bristle model that exhibits exact stick-slip and hysteresis. We next develop an asperity-based friction model in which the vertical motion of the body leads to the Stribeck effect. The friction model is hysteretic and the energy-dissipation mechanism is the sudden release of the compressed bristles. We show that this bristle model is a generalization of the LuGre model. The final contribution of this dissertation is a framework for relating butterfly-shaped hysteresis maps to simple hysteresis maps, which are typically easier to model and more amenable to control design. In particular, a unimodal mapping is used to transform simple loops to butterfly loops.

Drincic, Bojana

302

A frequency-dependent hysteresis model for power ferrites up to curie temperatures  

Microsoft Academic Search

A methodology is presented for the modeling of hysteresis in bulk manganese-zinc (MnZn) power ferrites over the practical ranges of amplitude and frequency from room temperature up to their Curie temperatures. The model parameters of an existing frequency-dependent hysteresis model are related to the typical magnetic properties such as the saturation flux density, the coercive force, and initial permeability. Temperature

Paiboon Nakmahachalasint; Khai D. T. Ngo; Loc Vu-Quoc

2004-01-01

303

Hysteresis Caused by Water Molecules in Carbon Nanotube Field-Effect Transistors  

Microsoft Academic Search

Carbon nanotube field-effect transistors commonly comprise nanotubes lying on SiO2 surfaces exposed to the ambient environment. It is shown here that the transistors exhibit hysteresis in their electrical characteristics because of charge trapping by water molecules around the nanotubes, including SiO2 surface-bound water proximal to the nanotubes. Hysteresis persists for the transistors in vacuum since the SiO2- bound water does

Woong Kim; Ali Javey; Ophir Vermesh; Qian Wang; Yiming Li; Hongjie Dai

2003-01-01

304

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

305

A practical model to analytically characterize the polarization hysteresis of ferroelectric capacitors  

Microsoft Academic Search

A simulation based comparative study of the polarization hysteresis of the ferroelectric capacitor using various ferroelectric models is presented. A 2-dimensional finite element device-level model was implemented using SILVACO's ATLAS device simulator to generate the polarization hysteresis characteristics for Au\\/Poly(vinylidene fluoride-trifluoroethylene)\\/Au metal-insulator-metal (MIM) device. Landau free energy expression for electric field in terms of polarization is also implemented in the

Bikash Shrestha; Ron Pieper; Wudyalew Wondmagegn; Duo Mao; Israel Mejia; Harvey Stiegler; Bruce E Gnade; Manuel Quevedo-Lopez

2012-01-01

306

A modified Prandtl-Ishlinskii model for modeling asymmetric hysteresis of piezoelectric actuators.  

PubMed

Piezoelectric actuators can offer high resolution of displacement and this makes them suitable for precise driving tasks. However, most piezoelectric actuators are made of piezoceramics which have a major drawback related to their natural hysteresis nonlinearity. To compensate the hysteresis nonlinearity of piezoelectric actuators, many hysteresis models have been proposed such as the Preisach model, the classical Prandtl-Ishlinskii model, and so on. This paper provides a new approach to model the asymmetric hysteresis nonlinearity of piezoelectric actuators. Unlike the classical Prandtl-Ishlinskii model, the proposed model is based on a combination of two asymmetric operators which can independently simulate the ascending branch and descending branch of hysteresis. Moreover, the proposed model can be calculated using the recursive least-squares method and this makes the model easy and convenient to be calculated. The validity of the proposed model is demonstrated by comparing its simulation results with experimental measurements. The results show that the proposed model is capable of modeling asymmetric hysteresis of piezoelectric actuators with very high accuracy. PMID:20442032

Jiang, Hao; Ji, Hongli; Qiu, Jinhao; Chen, Yuansheng

2010-05-01

307

A new method of calculating magnetic hysteresis and thermal effects  

NASA Astrophysics Data System (ADS)

All the easy theoretical problems in rock magnetism have been solved. Further advances involve models of hysteresis and thermal fluctuations in increasingly complex systems. To model the physics of such systems accurately, rock magnetists will need to solve two seemingly unrelated technical challenges. First, for models of thermal relaxation (with applications to magnetic viscosity, thermoremanent magnetization and so on), they will need to locate energy barriers in multidimensional parameter spaces - a difficult and computationally expensive problem. Second, they will need to improve calculations of magnetization curves near jumps, where the slope of the curve almost always approaches infinity. Micromagnetic models have trouble locating jumps accurately. A new algorithm is presented that tackles both of these problems while greatly reducing the time needed to calculate magnetization curves. The most novel aspect of this algorithm is the way it treats the magnetic field. Other methods solve for the magnetization at a given magnetic field, change the field, and then solve for the magnetization again while the field is kept fixed at the new value. The result is an equilibrium curve in a space of magnetization and field components. The new algorithm treats the field the same way as it treats the magnetization. It uses a tangent to the magnetization curve to estimate the next point on the curve and a corrector algorithm that refines the estimate. There is also an adaptive algorithm to determine an appropriate distance to step along the curve. This algorithm is much more robust near jumps. It can also calculate energy barriers because the top of an energy barrier (a saddle point) is on the same solution curve as the stable magnetization states. Previous methods could not follow the solution curve past the point of instability, but this method can because of the way it handles the field. This makes it possible to calculate energy barriers much faster and more accurately than any previous method. Applications to interacting fine particles will be presented.

Newell, A.

2008-12-01

308

On the hysteresis of argon adsorption in a uniform closed end slit pore.  

PubMed

We present a molecular simulation study of adsorption and desorption in slit mesopores of uniform width with one end closed and explore the effects of pore dimensions (width and length), temperature and surface affinity on the hysteresis loop: its position, lower and upper closure points, area and shape. Our results show that the metastability, brought about by structural change in the adsorbate, is the reason for the existence of hysteresis, and contrast with reports suggesting that reversibility invariably prevails for adsorption in closed end pores. The shape, area and position of the hysteresis loop are complex functions of pore width, length and temperature. We establish a parametric map of the boundary separating reversible and hysteretic regions. Our simulation results also show a number of interesting observations that have not been previously reported or generally recognised: (1) the fluid within the core of the pore behaves like a bulk liquid as the pore is progressively filled, via the movement of the meniscus from the closed end to the pore mouth, but as the pore fills, the fluid in the core becomes structured, (2) the shape of the meniscus changes as adsorption progresses but is constant during desorption because of the constant thickness of the adsorbed layer in the two-phase region, (3) the hysteresis loop is larger for a longer pore, (4) the area of the hysteresis loop increases with pore width up to a certain width, beyond which it decreases and finally disappears, (5) as temperature approaches the critical hysteresis temperature, the hysteresis loop area decreases, but it retains its Type H1 character. PMID:23746436

Fan, Chunyan; Do, D D; Nicholson, D

2013-09-01

309

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

310

Adsorption Hysteresis and its Effect on CO2 Sequestration and Enhanced Coalbed Methane Recovery  

NASA Astrophysics Data System (ADS)

CO2 sequestration in coal reservoirs is a promising technology for reducing atmospheric CO2 concentrations. Of the candidates for geological sequestration, the physics of transport and sequestration in coal is the least well understood. Adsorption hysteresis has been observed for pure gas adsorption on some coals. It is manifest as desorption curves where the loading of gas on coal surfaces is greater than sorption at the same pressure. Current simulation technology does not have the functionality to incorporate this phenomenon that has a potentially great effect on sequestration in coalbeds. Understanding the interplay between adsorption and desorption of gas species, phase behaviour and convection is paramount to designing safe and effective sequestration projects. Our work integrates experiments and theory development. Isotherms of CH4, N2 and CO2 were measured on a sample of coal from the Powder River Basin, WY, for adsorption and desorption paths. Hysteresis was observed for all gases. Likewise, the displacment of methane by various mixtures of N2 and CO2 was also measured. Simultaneously, a model was developed to solve for the dispersion-free limit of convective transport in multiphase systems with adsorption, including the effects of volume change as components transfer from vapour to liquid and solid phases. Analytical solutions were obtained using the method of characteristics. These solutions were compared against corresponding solutions without adsorption hysteresis. For pure gas injection, in which the amount of adsorbed injected gas increases monotonically and the amount of adsorbed initial gas decreases monotonically, hysteresis effects were not observed. For injection gas mixtures of N2-CO2 displacing CH4, CO2 and N2 separated chromatographically and hysteresis effected breakthrough and bank arrival times as well as shifted overall component concentrations as the displacement progressed. When injection gas mixtures were rich in N2, the structures remained similar, but arrival times of component banks were delayed compared to solutions that did not account for adsoprtion hysteresis. For injection gas mixtures rich in CO2, completely different composition route resulted when hysteresis effects were included. From this analysis, adsoprtion hysteresis significantly affects displacement behaviour, impacting process efficiency and recovery time. Neglecting this effect can potentially lead to poor business decisions. For coals that exhibit this behaviour, hysteresis should be included in order to accurately predict displacement behaviour.

Seto, C. J.; Tang, G. T.; Jessen, K.; Kovscek, A. R.; Orr, F. M.

2006-12-01

311

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

312

Design of hysteresis-compensating iterative learning control for piezo-positioners: Application to atomic force microscopes  

Microsoft Academic Search

This article addresses hysteresis-caused positioning error in piezo-based systems, such as atomic force microscopes. First, we present the design of an iterative learning control algorithm based on the Preisach hysteresis model. For a given output bound, we determine the algorithm’s rate of convergence. Second, we compensate for creep in the piezo system to determine a hysteresis model, and then the

Kam K. Leang; Santosh Devasia

2006-01-01

313

Comparison of contact angle hysteresis of different probe liquids on the same solid surface.  

PubMed

Advancing and receding contact angles of water, formamide and diiodomethane were measured on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) layers deposited on three different solid supports-glass, mica and poly(methyl methacrylate). Up to five statistical monolayers were deposited on the surfaces by spreading DPPC solution. It was found that even on five statistical DPPC monolayers, the hysteresis of a given liquid depends on the kind of solid support. Also on the same solid support the contact angle hysteresis is different for each probe liquid used. The AFM images show that the heights of roughness of the DPPC films cannot be the primary cause of the observed hysteresis because the heights are too small to cause the observed hystereses. It is believed that the hysteresis is due to the liquid film present right behind the three-phase solid surface/liquid drop/gas (vapour) contact line and the presence of Derjaguin pressure. The value of contact angle hysteresis depends on both the solid surface and liquid properties as well as on intermolecular interactions between them. PMID:23335833

Chibowski, Emil; Jurak, Malgorzata

2013-02-01

314

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

315

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

316

Dual carrier traps related hysteresis in organic inverters with polyimide-modified gate-dielectrics  

NASA Astrophysics Data System (ADS)

We integrated pentacene- and NN'-diheptyl-3,4,9,10-perylenebiscarboximide-based transistors into an organic complementary metal oxide semiconductor (O-CMOS) whose gate-dielectric surface was modified by polyimide (PI). The hysteresis behaviors in metal-oxide-semiconductors, field-effect transistors, and O-CMOS were reported clearly. Measurements of hysteresis showed that the PI exhibited high trapping and detrapping speeds for charge carriers, including holes and electrons, to result in high performance transistors and O-CMOSs; moreover, the trapping and detrapping speeds were matched. Finally, a PI-modified organic inverter with little hysteresis, low static power dissipation, high noise margins, and switching voltage near VDD/2 was achieved simultaneously.

Chou, Wei-Yang; Yeh, Bo-Liang

2010-04-01

317

Dynamic hysteresis and scaling behavior for Pb(Zr,Ti)O3 ceramics  

NASA Astrophysics Data System (ADS)

The dynamic hysteresis of Nb-doped Pb(ZrxTi1-x)O3 (PZT, 0.40 ? x ? 0.60) ceramics with different phase structures was investigated as functions of frequency f and electric field amplitude E0. When E0 grows over ˜1.5 times of coercive field Ec, all the loops become well saturated and their scaling relations of hysteresis area ?A? against f and E0 can be expressed with an identical form as ?A??f0.01E00.10 for either tetragonal phase or morphotropic phase, which is in good agreement with our previous result of rhombohedral PZT [Chen et al., J. Appl. Phys. 114, 244101 (2013)]. The results indicate that ferroelectrics with fairly distinct domain structures could have similar dynamic hysteresis and scaling behavior at high-E0 region.

Chen, Xuefeng; Dong, Xianlin; Zhou, Zhiyong; Wang, Junxia; Cao, Fei; Wang, Genshui; Zhang, Hongling

2014-03-01

318

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

319

Combinatorial search of thermoelastic shape-memory alloys with extremely small hysteresis width.  

PubMed

Reversibility of structural phase transformations has profound technological implications in a wide range of applications from fatigue life in shape-memory alloys (SMAs) to magnetism in multiferroic oxides. The geometric nonlinear theory of martensite universally applicable to all structural transitions has been developed. It predicts the reversibility of the transitions as manifested in the hysteresis behaviour based solely on crystal symmetry and geometric compatibilities between phases. In this article, we report on the verification of the theory using the high-throughput approach. The thin-film composition-spread technique was devised to rapidly map the lattice parameters and the thermal hysteresis of ternary alloy systems. A clear relationship between the hysteresis and the middle eigenvalue of the transformation stretch tensor as predicted by the theory was observed for the first time. We have also identified a new composition region of titanium-rich SMAs with potential for improved control of SMA properties. PMID:16518396

Cui, Jun; Chu, Yong S; Famodu, Olugbenga O; Furuya, Yasubumi; Hattrick-Simpers, Jae; James, Richard D; Ludwig, Alfred; Thienhaus, Sigurd; Wuttig, Manfred; Zhang, Zhiyong; Takeuchi, Ichiro

2006-04-01

320

A measurement technique for circumventing hysteresis and conductance drift in carbon nanotube field-effect transistors  

NASA Astrophysics Data System (ADS)

We present a measurement protocol that effectively eliminates both the hysteresis and the temporal drift typically observed in the channel conductance of single-walled carbon nanotube field-effect transistors (SWNT FETs) during the application of gate voltages. Before each resistance measurement, the gate is first stepped through a series of alternating positive and negative voltages to produce a neutral charge distribution within the device. This process is highly effective at removing the hysteresis in the channel conductance, and time-dependent measurements further demonstrate that the drain current is stable and single-valued, independent of the prior measurement history. The effectiveness of this method can be understood within the Preisach hysteresis model, which we demonstrate as a useful framework to predict the observed results.

Tunnell, Andrew; Ballarotto, Vincent; Cumings, John

2014-01-01

321

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

PubMed

Smart actuators are the key components in a variety of nanopositioning applications, such as scanning probe microscopes and atomic force microscopes. Piezoelectric actuators are the most common smart actuators due to their high resolution, low power consumption, and wide operating frequency but they suffer hysteresis which affects linearity. In this paper, an innovative digital charge amplifier is presented to reduce hysteresis in piezoelectric stack actuators. Compared to traditional analog charge drives, experimental results show that the piezoelectric stack actuator driven by the digital charge amplifier has less hysteresis. It is also shown that the voltage drop of the digital charge amplifier is significantly less than the voltage drop of conventional analog charge amplifiers. PMID:24784651

Bazghaleh, Mohsen; Grainger, Steven; Cazzolato, Ben; Lu, Tien-Fu; Oskouei, Reza

2014-04-01

322

Understanding the Link Between Nanoscale Microstructural Features and Dynamic Hysteresis Phenomena  

SciTech Connect

A Nd–Dy–Fe–B alloy was designed to exhibit high coercivity and optimum loop shapes utilizing a combination of intrinsic and extrinsic alloy design principles. After achieving these initial goals, conventional structural analysis using X-ray and TEM could explain the salient features of the observed hysteresis behavior. However, greater understanding could be gained on the complex dynamic behavior of hysteresis through the exploitation of a new recoil technique that was developed, which focuses on switching field distributions arising from irreversible magnetic behavior. Utilizing this approach, we have successfully linked specific magnetic reversal behavior with distinct magnetic phases that have characteristic microstructural length scales. This new approach may become a powerful tool for the study of the structure–property–hysteresis behavior of hard magnetic materials.

Meacham, Brian Eugene; Branagan, Daniel James; Shield, J. E.

2004-06-01

323

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

324

Multistability and hysteresis in the climate-cryosphere system under orbital forcing  

NASA Astrophysics Data System (ADS)

Using the Earth system model of intermediate complexity CLIMBER-2 we studied the stability diagram of the climate-cryosphere system in the phase space of Milankovitch forcing (maximum summer insolation at 65°N, abbreviated as MF). We have shown that the equilibrium response of the climate-cyrosphere system to MF reveals pronounced hysteresis behavior within the range of Earth's orbital parameters. Depending on MF, the climate-cryosphere system has either one (glacial or interglacial) or two different equilibrium states. The MF thresholds of the transitions between the two states depend on parameterizations of ice-sheet dynamics, but are rather insensitive to the choice of the orbital parameters used to obtain the same value of MF. A change of atmospheric CO2 concentration from its interglacial to the glacial value, shifts the hysteresis curve by about 15 W/m2. These results provide an important support to the conceptual models of glacial cycles based on multistability and hysteresis behavior.

Calov, Reinhard; Ganopolski, Andrey

2005-11-01

325

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

SciTech Connect

We have studied the low spin to high spin phase transition induced by nanosecond laser pulses outside and within the thermal hysteresis loop of the [Fe(Htrz){sub 2} trz](BF{sub 4}){sub 2}-H{sub 2}O spin crossover nanoparticles. We demonstrate that, whatever the temperature of the compound, the photo-switching is achieved in less than 12.5 ns. Outside the hysteresis loop, the photo-induced high spin state remains up to 100 {mu}s and then relaxes. Within the thermal hysteresis loop, the photo-induced high spin state remains as long as the temperature of the sample is kept within the thermal loop. A Raman study indicates that the photo-switching can be completed using single laser pulse excitation.

Galle, G.; Degert, J.; Freysz, E. [Universite de Bordeaux, LOMA, UMR-CNRS 5798, 351 cours de la Liberation, 33405 Talence Cedex (France)] [Universite de Bordeaux, LOMA, UMR-CNRS 5798, 351 cours de la Liberation, 33405 Talence Cedex (France); Etrillard, C.; Letard, J.-F. [CNRS, Universite de Bordeaux, ICMCB, UPR CNRS 9048, 87 Avenue du Docteur Albert Schweitzer, 33608 Pessac Cedex (France)] [CNRS, Universite de Bordeaux, ICMCB, UPR CNRS 9048, 87 Avenue du Docteur Albert Schweitzer, 33608 Pessac Cedex (France); Guillaume, F. [Universite de Bordeaux, ISM, UMR CNRS 5255, 351 cours de la Liberation, 33405 Talence Cedex (France)] [Universite de Bordeaux, ISM, UMR CNRS 5255, 351 cours de la Liberation, 33405 Talence Cedex (France)

2013-02-11

326

Scaling of hysteresis loop of interacting polymers under a periodic force  

NASA Astrophysics Data System (ADS)

Using Langevin dynamics simulations, we study a simple model of interacting-polymer under a periodic force. The extension curves strongly depend on the magnitude of the amplitude (F) and the frequency (?) of the applied force. In low frequency limit, the system retraces the thermodynamic path. At higher frequencies, response time is greater than the external time scale for change of force, which restrict the biomolecule to explore a smaller region of phase space that results in hysteresis of different shapes and sizes. We show the existence of dynamical transition, where area of hysteresis loop approaches to a large value from nearly zero value with decreasing frequency. The area of hysteresis loop is found to scale as F??? for the fixed length. These exponents are found to be the same as of the mean field values for a time dependent hysteretic response to periodic force in case of the isotropic spin.

Mishra, Rakesh Kumar; Mishra, Garima; Giri, Debaprasad; Kumar, Sanjay

2013-06-01

327

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

328

Elastic hysteresis phenomena in ULE and Zerodur optical glasses at elevated temperatures  

SciTech Connect

Elastic hysteresis phenomena were observed in ULE and Zerodur glasses at elevated temperatures up to glass transition. These effects were found under load deformation testing using four-point bending. Permanent creep resulted in Zerodur at 900/degree/C and in ULE at 1000/degree/C. The deformation was monitored at mid-span of the samples with a capacitance-type transducer having 0.01 micrometer resolution. These hysteresis effects may be classified as elastic bimodulus between loading and unloading; that is, two different elastic moduli were observed between loading and unloading. Upon complete unloading, a minimal deformation state promptly returned, indicating little or no viscoelastic creep. The hysteresis effect may be attributed to a change in glass structure as a function of stress state. A description of the test apparatus and procedure, test results for both glasses at several elevated temperatures, and an elementary discussion of continuum theory of constitutive behavior are included. 6 refs., 9 figs.

Wilkins, S.C.; Coon, D.N.; Epstein, J.S.

1988-01-01

329

Scaling of hysteresis loop of interacting polymers under a periodic force.  

PubMed

Using Langevin dynamics simulations, we study a simple model of interacting-polymer under a periodic force. The extension curves strongly depend on the magnitude of the amplitude (F) and the frequency (?) of the applied force. In low frequency limit, the system retraces the thermodynamic path. At higher frequencies, response time is greater than the external time scale for change of force, which restrict the biomolecule to explore a smaller region of phase space that results in hysteresis of different shapes and sizes. We show the existence of dynamical transition, where area of hysteresis loop approaches to a large value from nearly zero value with decreasing frequency. The area of hysteresis loop is found to scale as F(?)?(?) for the fixed length. These exponents are found to be the same as of the mean field values for a time dependent hysteretic response to periodic force in case of the isotropic spin. PMID:23822272

Mishra, Rakesh Kumar; Mishra, Garima; Giri, Debaprasad; Kumar, Sanjay

2013-06-28

330

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

331

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

332

Domain Dynamics in Piezoresponse Force Spectroscopy: Quantitative Deconvolution and Hysteresis Loop Fine Structure  

SciTech Connect

Domain dynamics in the Piezoresponse Force Spectroscopy (PFS) experiment is studied using the combination of local hysteresis loop acquisition with simultaneous domain imaging. The analytical theory for PFS signal from domain of arbitrary cross-section and length is developed for the analysis of experimental data on Pb(Zr,Ti)O3 polycrystalline films. The results suggest formation of oblate domain at early stage of the nucleation and growth, consistent with efficient screening of depolarization field. The fine structure of the hysteresis loop is shown to be related to the observed jumps in the domain geometry during domain wall propagation (nanoscale Barkhausen jumps), indicative of strong domain-defect interactions.

Bdikin, Igor [University of Aveiro, Portugal; Kholkin, Andrei [University of Aveiro, Portugal; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine; Svechnikov, S. V. [National Academy of Science of Ukraine, Kiev, Ukraine; Kim, S.-H. [INOSTEK Inc., Gyeonggi, Korea; Kalinin, Sergei V [ORNL

2008-01-01

333

Disorder Identification in Hysteresis Data: Recognition Analysis of the Random-Bond-Random-Field Ising Model  

SciTech Connect

An approach for the direct identification of disorder type and strength in physical systems based on recognition analysis of hysteresis loop shape is developed. A large number of theoretical examples uniformly distributed in the parameter space of the system is generated and is decorrelated using principal component analysis (PCA). The PCA components are used to train a feed-forward neural network using the model parameters as targets. The trained network is used to analyze hysteresis loops for the investigated system. The approach is demonstrated using a 2D random-bond-random-field Ising model, and polarization switching in polycrystalline ferroelectric capacitors.

Ovchinnikov, O. S. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Jesse, S.; Kalinin, S. V. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Bintacchit, P.; Trolier-McKinstry, S. [Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2009-10-09

334

Analysis of Hysteresis Measurements in Epitaxial SRO\\/PZT\\/Pt Capacitor Structures  

Microsoft Academic Search

P-E hysteresis loops were measured in SrRuO3\\/Pb(Zr0.52Ti0.48)O3\\/Pt capacitor structures grown on (100) SrTiO3 single-crystal substrates using high-oxygen pressure on axis dc-sputtering technique. PZT films were grown by rf magnetron sputtering in a pure oxygen atmosphere. Capacitor structures with electrode areas of 5.0 × 10 and 6.5 × 10cm revealed clear hysteretic behavior. These hysteresis loops displayed asymmetric behavior due to

J. Realpe; A. Cortes; E. Delgado; W. Lopera; P. Prieto

2006-01-01

335

Water as origin of hysteresis in zinc tin oxide thin-film transistors.  

PubMed

The hysteresis behavior of transparent zinc tin oxide (ZTO) thin film transistors (TFTs) is identified to be a result of short-term bias stress induced by the measurement. The related density of shallow defect states can be adjusted by the amount of water in the ambient. Time-resolved studies of the TFTs under varied ambient demonstrate that hysteresis can be immediately switched on and off by the adsorption and desorption of water, respectively. These findings are expected to be of general importance also for other oxide-based TFTs. PMID:22939293

Fakhri, M; Johann, H; Görrn, P; Riedl, T

2012-09-26

336

Effect of the distribution of anisotropy constants on hysteresis losses for magnetic hyperthermia applications  

NASA Astrophysics Data System (ADS)

Magnetic hyperthermia using magnetic nanoparticles is a potential remedial therapy for the reduction of cancer and other tumours. The dominant heating mechanism is hysteresis heating. This means that control of the particle size distribution is essential. However, control of the anisotropy dispersion is also required. We have calculated the effect of the anisotropy distribution on the hysteresis heating in magnetic nanoparticles for hyperthermia applications. Where there is a wide distribution of anisotropy constants the heat output is controlled by the distribution of anisotropy constants. This effect is significant in systems such as magnetite particles where shape anisotropy dominates.

Vallejo-Fernandez, G.; O'Grady, K.

2013-09-01

337

Negative and positive hysteresis in double-cavity optical bistability in a three-level atom  

NASA Astrophysics Data System (ADS)

We present dual hysteretic behavior of a three-level ladder system exhibiting optical bistability in a double-cavity configuration in the mean-field limit. The two fields coupling the atomic system experience competing cooperative effects along the two transitions. We observe a hump-like feature in the bistable curve arising due to cavity-induced inversion, which transforms into a negative-hysteresis loop. Apart from negative- and positive-hysteresis regions, the system offers a variety of controllable nonlinear dynamical features, ranging from switching, periodic self-pulsing to chaos.

Babu, H. Aswath; Wanare, Harshawardhan

2011-03-01

338

Charge transfer hysteresis in graphene dual-dielectric memory cell structures  

NASA Astrophysics Data System (ADS)

We report controlled charge transfer between large-area graphene and a dual-dielectric, silicon nitride/silicon oxide substrate. Graphene was grown on copper by chemical vapour deposition, transferred to the nitride substrates, and patterned into test structures. Hysteresis in conductance with varying gate voltage is easily understood in terms of electron transfer between graphene and nitride traps. Increased hysteresis with temperature suggests thermally activated charge transfer of a Poole-Frenkel or Schottky nature. A 7.3× change in graphene sheet resistance is observed at room temperature with the nitride in a charged and discharged state.

Imam, S. A.; Deshpande, T.; Guermoune, A.; Siaj, M.; Szkopek, T.

2011-08-01

339

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

340

A hysteresis effect in photoconductive cadmium selenide and its use in a solid-state image storage device  

Microsoft Academic Search

A brief description of a new hysteresis effect in cadmium selenide photoconductive powder will be given. Photocurrent plotted as a function of voltage has the form of a hysteresis loop, with triggering from low to high currents occurring at a voltage depending on the incident light level. At a suitably chosen voltage, triggering from low to high currents occurs with

F. H. Nicoll

1957-01-01

341

A neuro-genetic and time-frequency approach to macromodeling dynamic hysteresis in the harmonic regime  

Microsoft Academic Search

A numerical approach for the evaluation of hysteresis loops in the harmonic regime is presented. Genetic algorithms (GAs) are used to train neural networks (NNs) with the aim of generalizing the Jiles-Atherton (JA) static hysteresis model for dynamic loops. The NN training is based on symmetrical and asymmetrical, major and minor loops under sinusoidal excitation with or without offset. Subsequently,

Alessandro Salvini; Francesco Riganti Fulginei; Christian Coltelli

2003-01-01

342

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

NASA Astrophysics Data System (ADS)

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

Wu, Jian-Wei; Bikash, Nakarmi

2013-08-01

343

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

PubMed

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

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

2013-04-01

344

Carrier mobility in insulating polymer influenced by hysteresis of applied voltage  

Microsoft Academic Search

Carrier mobility is one of the most important parameters to characterize dielectrics. The mobility, however, may have a hysteresis when subjected to a high field. Indeed it is reported that a polymeric film specimen that has been subjected to a high field is more conductive than the virgin specimen, suggesting the rise in mobility. Therefore, we tried a direct measurement

Y. Murakami; M. Nemoto; N. Hozumi; M. Nagao

2005-01-01

345

Contact-Angle Hysteresis Caused by a Random Distribution of Weak Heterogeneities on a Solid Surface  

Microsoft Academic Search

A model according to which contact-angle hysteresis arises as the result of a random distribution of irregularities on the solid surface is investigated on the basis of probability theory. An estimate is obtained of the mathematical expectation of the number of stable equilibria when the effective angle between the liquid–gas surface and the solid surface with which the liquid is

U. Öpik

2000-01-01

346

Hysteresis in photoelectric charging of dust particles in a complex plasma  

SciTech Connect

Starting with the basic equations of number and energy balance along with charge neutrality it is shown that the charge on the particle versus irradiance of incident radiation plot in a complex plasma, illuminated by radiation with periodic irradiance displays hysteresis.

Sodha, M. S.; Srivastava, Sweta [Disha Institute of Management and Technology, Satya Vihar, Vidhan Sabha-Chandrakhuri Marg, Mandir Hasaud, Raipur-492101 (India); Mishra, S. K.; Misra, Shikha [Department of Education Building, University of Lucknow, Lucknow 226007 (India)

2010-05-15

347

CMOS Schmitt Trigger Circuit with Controllable Hysteresis Using Logical Threshold Voltage Control Circuit  

Microsoft Academic Search

A simple logical threshold voltage control circuit is proposed. It can be implemented using normal conventional CMOS inverters. The proposed circuit is able to control a logical threshold voltage of a gate linearly and continuously over a range of a power supply voltage. Applications to the Schmitt trigger circuit with controllable hysteresis and a window comparator are shown to demonstrate

Cong-kha Pham

2007-01-01

348

Modeling of micromagnetic Barkhausen activity using a stochastic process extension to the theory of hysteresis  

SciTech Connect

Recent work by Bertotti [IEEE Trans. Magn. [bold MAG]-[bold 24], 621 (1988)] and others has shown that it is possible to model the micromagnetic Barkhausen discontinuities at the coercive point using a two-parameter stochastic model. However, the present formulation of the model is restricted to limited regions of the hysteresis curve over which [ital dM]/[ital dH] is approximately constant and when [ital dH]/[ital dt] is held at a constant rate. A natural extension of this model is to take the basic result, in which the level of Barkhausen activity in one time period is related to the activity in the previous time period, and increment it by a small amount which is dependent on the differential permeability. The extension of the model proposed here uses the theory of ferromagnetic hysteresis to determine the differential permeability at any point of the hysteresis loop. The Barkhausen activity is then assumed to vary in proportion to the differential permeability. The resulting model allows the Barkhausen sum of discontinuous changes in magnetization to be modelled around the entire hysteresis loop, leading to an important generalization of the basic model.

Jiles, D.C. (Ames Laboratory, Center for Nondestructive Evaluation, Department of Materials Science and Engineering and Department of Electrical Engineering, Iowa State University, Ames, Iowa 50011 (United States)); Sipahi, L.B. (Ames Laboratory, Center for Nondestructive Evaluation, and Department of Physics, Iowa State University, Ames, Iowa 50011 (United States)); Williams, G. (Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States))

1993-05-15

349

Hysteresis of the phase transformation detected by galvanomagnetic measurements of Ag2Se layers  

Microsoft Academic Search

Temperature dependence of the resistivity, carrier concentration, and carrier mobility have been investigated in vacuum deposited Ag2Se thin layers. Properties of silver selenide layers developed by the reaction of poly- and monocrystalline parent Ag films and selenium on NaCl substrates in identical circumstances have been described and compared with one another. Experimental evidences of the hysteresis of the electrical properties

K. Somogyi; G. Sáfrán

1995-01-01

350

Compound control with hysteresis-band switching for LOS stabilization system  

Microsoft Academic Search

The gyro stabilized platform control is required to isolate the line of sight (LOS) from the disturbance and vibration of carrier and ensure pointing and tracking for target in electro-optical tracking system. A compound adaptive fuzzy PID control with hysteresis-band switching is developed for this servo system with nonlinear property and some uncertainties. Here, in the adaptive fuzzy controller, the

Wei Ji; Bo Xu; Jinliang Guo; Qi Li

2010-01-01

351

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

352

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

353

Hysteresis of transport critical current of high Tc superconductors in strong magnetic fields. Theory  

Microsoft Academic Search

A new model is developed to describe the properties of a Josephson junction critical current in a strong magnetic field. A comparison with experiments shows the possibility of the existence of a surface barrier to the Abrikosov vortex motion in YBCO-124 metalceramics. Characteristic features of this barrier appear in the abnormal hysteresis loop of the transport critical current.

A. I. D'Yachenko

1993-01-01

354

A current transformer model based on the Jiles-Atherton theory of ferromagnetic hysteresis  

Microsoft Academic Search

The hysteresis loop of the core material in a test current transformer is simulated using the Jiles-Atherton theory. Comparisons are made between recorded and simulated waveforms and it is found necessary to replace the modified Langevin function used by Jiles and Atherton. Using an alternative function described in the paper, good agreement is achieved between test and simulated waveforms

U. D. Annakkage; P. G. McLaren; E. Dirks; R. P. Jayasinghe; A. D. Parker

2000-01-01

355

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

Microsoft Academic Search

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

Peter J. Chen; Stephen T. Montgomery

1980-01-01

356

Graphene on a Hydrophobic Substrate: Doping Reduction and Hysteresis Suppression under Ambient Conditions  

Microsoft Academic Search

The intrinsic doping level of graphene prepared by mechanical exfoliation and standard lithography procedures on thermally oxidized silicon varies significantly and seems to depend strongly on processing details and the substrate morphology. Moreover, transport properties of such graphene devices suffer from hysteretic behavior under ambient conditions. The hysteresis presumably originates from dipolar adsorbates on the substrate or graphene surface. Here,

Myrsini Lafkioti; Benjamin Krauss; Timm Lohmann; Ute Zschieschang; Hagen Klauk; Klaus V. Klitzing; Jurgen H. Smet

2010-01-01

357

Domain observations of titanomagnetites during hysteresis at elevated temperatures and thermal cycling  

Microsoft Academic Search

Domain observations using Bitter patterns have been made on x = 0.6 titanomagnetites up to the Curie point. The principal results are: (1) there is no major increase in the number of domain walls before they are lost near the Curie point; (2) with increasing temperature, the fields at which saturation is reached and departed from during hysteresis decrease; (3)

M. Metcalf; M. Fuller

1987-01-01

358

A Wind-Induced Thermohaline Circulation Hysteresis and Millennial Variability Regimes  

Microsoft Academic Search

The multiple equilibria of the thermohaline circulation (THC: used here in the sense of the meridional overturning circulation) as function of the surface freshwater flux has been studied intensively following a Stommel paper from 1961. It is shown here that multistability and hysteresis of the THC also exist when the wind stress amplitude is varied as a control parameter. Both

Yosef Ashkenazy; Eli Tziperman

2007-01-01

359

Boiling hysteresis of impinging circular submerged jets with highly wetting liquids  

Microsoft Academic Search

An experimental study was carried out to characterize the boiling hysteresis of impinging circular submerged jets with highly wetting liquids. The effects of noncondensable gases and surface aging on boiling curves were considered. The present study focused on the effects of jet parameters (jet exit velocity, radial distance from the stagnation point and nozzle diameter) and fluid subcooling on incipient

D. W. Zhou; C. F. Ma; J. Yu

2004-01-01

360

Evaluation of Magnetic Field Hysteresis and Flux Creep of a QMG Coil Magnet  

Microsoft Academic Search

This paper presents an evaluation of the magnetic hysteresis of a coil type QMG magnet for a high field application of oxide bulk high Tc superconductors (HTS). The QMG is a high Jc bulk material, which consists of single crystalline 123 with finely dispersed 211. The bulk coil is made from a slice of Ag doped Gd based QMG by

Masanori Tsuchimoto; Shinichiro Osanai; Mitsuru Morita

2007-01-01

361

The influence of the shape of domains on the ferroelectric hysteresis loop  

Microsoft Academic Search

Simple models of the polarization reversal in ferroelectrics with domains in the shape of either circular cylinders or parallel strips, which grow only by sideways expansion, are used to calculate the hysteresis loops and particularly the coercive field as a function of the amplitude and frequency of a sinusoidal electric field. The small differences in results corresponding to various models

Jiri Janta

1971-01-01

362

Thermomechanical modeling of polycrystalline SMAs under cyclic loading, Part IV: modeling of minor hysteresis loops  

Microsoft Academic Search

A thermomechanical model for the hysteretic response of Shape Memory Alloys (SMAs) is proposed in this paper by expanding a previous model developed by Bo and Lagoudas (Z. Bo, D.C. Lagoudas, International Journal of Engineering Science, accepted) to include minor hysteresis loops. The constitutive model for SMAs previously developed by Bo and Lagoudas is reviewed first, and a simplification for

Zhonghe Bo; Dimitris C. Lagoudas

1999-01-01

363

Physical interpretation of hysteresis loops: Micromagnetic modeling of fine particle magnetite  

Microsoft Academic Search

Hysteresis measurements have become an important part of characterizing magnetic behavior of rocks in paleomagnetic studies. Theoretical interpretation is often difficult owing to the complexity of mineral magnetism and published data sets demonstrate remanence and coercivity behavior that is currently unexplained. In the last decade, numerical micromagnetic modeling has been used to simulate magnetic particles. Such simulations reveal the existence

Lisa Tauxe; H. Neal Bertram; Christian Seberino

2002-01-01

364

The effects of stress on a ferromagnet on a minor hysteresis loop  

Microsoft Academic Search

Reversible and irreversible changes in magnetization due to stress on a minor hysteresis loop were studied at various magnetic field strengths. It was found that the irreversible changes were not always directed toward the principal anhysteretic, contrary to Jiles and Atherton's hypothesis (1986). Also, two different demagnetization methods were used within the minor loop to test the existence of postulated

DAVID L. ATHERTON; V. Ton

1990-01-01

365

Tuning size and magnetic thermal hysteresis in a new near room temperature spin crossover compound.  

PubMed

A mononuclear spin crossover compound Fe(AP-Mesal)2, which exhibits spin transitions near room temperature and light induced excited spin state trapping (LIESST) effects at low temperature, was synthesized and substructured in the form of micro- and nanoscaled particles. A thermal hysteresis loop was detected with particle size reduction to microscale and nanoscale. PMID:23633082

Zhang, Li; Wang, Juan-Juan; Xu, Guan-Cheng; Li, Jing; Jia, Dian-Zeng; Gao, Song

2013-06-21

366

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

367

Observation of Hysteresis of the Ion Cloud Motion in an rf Trap  

NASA Astrophysics Data System (ADS)

Variations of the hysteresis of the rf detection signals corresponding to the axial motion of an ion cloud in a Paul trap versus the detection voltage, operation parameters and number of ions have been observed. The features are explained by an extended pseudopotential model with an octupole potential correction and an effective potential from the ion cloud.

Gao, Ke-lin; Luo, Xue-li; Zhu, Xi-wen; Yan, Min; Li, Jiao-mei

1997-08-01

368

Curing Characteristics, Fatigue and Hysteresis Behaviour of Feldspar Filled Natural Rubber Vulcanizates  

Microsoft Academic Search

Curing characteristics, fatigue, and hysteresis behaviour of feldspar filled SMR L vulcanizates and feldspar filled ENR 50 vulcanizates were studied. Two different types of natural rubber, SMR L and ENR 50 having 0 and 50 mol% of epoxide groups were used. The feldspar filled natural rubber vulcanizates were compared at similar filler loading which were used at 0, 10, 20, and

H. Ismail; H. Osman; A. Ariffin

2007-01-01

369

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

Microsoft Academic Search

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

A. A. Adly; H. H. Hanafy

2009-01-01

370

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

NASA Astrophysics Data System (ADS)

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

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

371

Hysteresis in discrete systems of possibly interacting elements with a double-well energy  

Microsoft Academic Search

Summary We study in this paper the hysteretic behavior of a discrete system constituted by a finite number of elements (“snap-springs”) whose energy has two parabolic wells. The guideline idea is that, in many circumstances, hysteresis can be due to the presence of relative minimizers of a potential (“metastable states”) in which the system might get locked during its quasistatic

B. Fedelich; G. Zanzotto

1992-01-01

372

A Probabilistic Multiscale Approach to Hysteresis in Shear Wave Propagation in Biotissue  

Microsoft Academic Search

Motivated by a problem involving wave propagation through viscoelastic biotissue, we present a theoretical framework for treating hysteresis as multiscale phenomena which must be averaged across distributions of internal variables. The resulting sys- tems entail probability measure dependent partial dierential equations for which we establish well-posedness in a framework that leads readily to computationally useful approximations.

H. T. Banks; Gabriella A. Pinter

2005-01-01

373

INVESTIGATION OF HYSTERESIS OF THE COANDA EFFECT AT THE FLAT PLATE  

Microsoft Academic Search

Summary: The hysteresis of the Coanda effect was investigated with the 2D stream coming from the slot in the neighbourhood of the plate at the experimental rig at the UWM, Olsztyn. The measurements were made for different Reynolds numbers based on the slot dimension and stream velocity. The measurement of the free stream, the wall jet velocity profiles and the

Aldona Skotnicka

2007-01-01

374

TiNiNb wide hysteresis shape memory alloy with low niobium content  

Microsoft Academic Search

Low niobium content dependence of the shape memory characteristic and transformation behavior in Ti–Ni–Nb alloy was studied in this paper. Ti46.9Ni50.1Nb3 alloy has excellent shape memory effect, and it can also exhibit enough wide transformation temperature hysteresis after deformation at Ms+30°C.

X. M. He; L. J. Rong; D. S. Yan; Y. Y. Li

2004-01-01

375

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

376

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

377

Hysteresis of switching waves and dissipative solitons in nonlinear magnetic metamaterials  

NASA Astrophysics Data System (ADS)

Localized structures forming in the bistable regimes in a chain of weakly coupled split ring resonators, which are the building blocks of a nonlinear magnetic metamaterial, where electric current is generated by external electromagnetic radiation, have been studied analytically and numerically. The hysteresis of the velocity of switching waves (fronts) has been revealed and discrete dissipative solitons have been found.

Rosanov, N. N.; Vysotina, N. V.; Shatsev, A. N.; Shadrivov, I. V.; Kivshar, Yu. S.

2011-08-01

378

Precise positioning of piezo-actuated stages using hysteresis-observer based control  

Microsoft Academic Search

The piezo-actuated stages are composed of the piezoelectric actuator and the positioning mechanism. The positioning accuracy of the piezo-actuated stage is limited due to hysteretic nonlinearity of the PEA and friction behaviour of the positioning mechanism. To compensate this nonlinearity of piezoelectric actuator, a PI feedback control associated with feedforward compensating based on the hysteresis observer is proposed in this

Chih-Jer Lin; Sheng-Ren Yang

2006-01-01

379

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

Microsoft Academic Search

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

Valerio Lucarini; Klaus Fraedrich; Frank Lunkeit

2010-01-01

380

Compressive and pseudo-elastic hysteresis behavior of entangled titanium wire materials  

Microsoft Academic Search

Two types of entangled titanium wire materials (ETWMs) have been fabricated through different procedures. Their entangled structure, compressive mechanical properties, and strain hysteresis behavior have been investigated. The experiment has demonstrated that the entangled wire structure can be adjusted when different fabrication methods are applied. The entangled wire morphologies can be normal entangled wires or coiled wires, and the pore

Ping Liu; Qingbiao Tan; Luhai Wu; Guo He

2010-01-01

381

Photovoltaic hysteresis and its ramifications for concentrator solar cell design and diagnostics  

Microsoft Academic Search

We report the observation of a photovoltaic effect with pronounced hysteresis. The phenomenon derives from the sharp transition in the dominant mode of electron transport in the tunnel diodes that regulate multijunction solar cells, and is only observable at high flux. These results emerged from measurements of cell current-voltage characteristics performed with miniature fiber-optic solar concentrators that can deliver flux

Jeffrey M. Gordon; Eugene A. Katz; Wondesen Tassew; Daniel Feuermann

2005-01-01

382

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

PubMed Central

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

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

2013-01-01

383

Triangular hysteresis loops in the spin-rotation region of orthoferrites  

NASA Astrophysics Data System (ADS)

A theory is proposed that qualitatively explains the shapes of the hysteresis loops in orthoferrites within the temperature interval of the magnetic reorientation transition. Triangular loops result from the strong temperature dependence of both the magnetic moment and the magnetic domain wall structure.

Bazaliy, Ya. B.; Tsymbal, L. T.

2010-08-01

384

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

385

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

386

Analysis and surface energy estimation of various model polymeric surfaces using contact angle hysteresis  

Microsoft Academic Search

Wetting of hydrophobic polymer surfaces commonly employed in electronic coatings and their interaction with surfactant-laden liquids and aqueous polymer solutions are analyzed using a contact angle hysteresis (CAH) approach developed by Chibowski and co-workers. In addition, a number of low surface tension acrylic monomer liquids, as well as common probe liquids are used to estimate solid surface energy of the

Ilker S. Bayer; Constantine M. Megaridis; Jie Zhang; Daniel Gamota; Abhijit Biswas

2007-01-01

387

Untangling perceptual memory: hysteresis and adaptation map into separate cortical networks.  

PubMed

Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain "decide" what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function). PMID:23236204

Schwiedrzik, Caspar M; Ruff, Christian C; Lazar, Andreea; Leitner, Frauke C; Singer, Wolf; Melloni, Lucia

2014-05-01

388

Apparent elastic modulus and hysteresis of skeletal muscle cells throughout differentiation  

NASA Technical Reports Server (NTRS)

The effect of differentiation on the transverse mechanical properties of mammalian myocytes was determined by using atomic force microscopy. The apparent elastic modulus increased from 11.5 +/- 1.3 kPa for undifferentiated myoblasts to 45.3 +/- 4.0 kPa after 8 days of differentiation (P < 0.05). The relative contribution of viscosity, as determined from the normalized hysteresis area, ranged from 0.13 +/- 0.02 to 0.21 +/- 0.03 and did not change throughout differentiation. Myosin expression correlated with the apparent elastic modulus, but neither myosin nor beta-tubulin were associated with hysteresis. Microtubules did not affect mechanical properties because treatment with colchicine did not alter the apparent elastic modulus or hysteresis. Treatment with cytochalasin D or 2,3-butanedione 2-monoxime led to a significant reduction in the apparent elastic modulus but no change in hysteresis. In summary, skeletal muscle cells exhibited viscoelastic behavior that changed during differentiation, yielding an increase in the transverse elastic modulus. Major contributors to changes in the transverse elastic modulus during differentiation were actin and myosin.

Collinsworth, Amy M.; Zhang, Sarah; Kraus, William E.; Truskey, George A.

2002-01-01

389

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

390

Disaggregation of Preisach hysteresis model and nonlinear function least-squares fit  

Microsoft Academic Search

This work presents a novel approach of modeling hysteresis using the Preisach model. Instead of relying entirely on the Presisach model, the hysteretic behavior is separated into a non-linear least squares fit function and a Preisach model. This separation allows for the independent analysis of the non-linear portion and hysterestic behavior of actuators. In particular, the paper addresses the response

Dragos Maciuca; Gopal Vasudevan

2008-01-01

391

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

PubMed

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

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

2006-03-01

392

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

393

Sorption-desorption of cadmium in aqueous palygorskite, sepiolite, and calcite suspensions: isotherm hysteresis.  

PubMed

Sorption isotherms have been widely used to assess the heavy metal retention characteristics of soil particles. Desorption behavior of the retained metals, however, usually differ from that of sorption, leading to a lack of coincidence in the experimentally obtained sorption and desorption isotherms. In this study, we examine the nonsingularity of cadmium (Cd) sorption-desorption isotherms, to check the possible hysteresis and reversibility phenomena, in aqueous palygorskite, sepiolite and calcite systems. Sorption of Cd was carried out using a 24-h batch equilibration experiment with eight different Cd solution concentrations, equivalent to 20-100% of maximum sorption capacity of each mineral. Immediately after sorption, desorption took place using successive dilution method with five consecutive desorption steps. Both Cd sorption and desorption data were adequately described by Freundlich equation (0.81hysteresis occurred in Cd sorption-desorption processes. The extent of hysteresis was quantified based on the differences obtained from sorption and desorption isotherms regarding the amount of Cd sorbed, the Freundlich exponent, and the Cd distribution coefficient. The results revealed that, sepiolite possessed the most hysteretic behavior among the minerals studied. Calcite showed much smaller hysteresis compared to the other two silicate clays at low Cd surface load, but its hysteresis indices significantly increased, and exceeded that of palygorskite, as the amount of Cd in the systems increased. The average amount of Cd released after five desorption steps, was 13.8%, 2.2% and 3.6% for the palygorskite, sepiolite and calcite, respectively, indicating that a large portion of Cd was irreversibly retained by the minerals. PMID:16870231

Shirvani, Mehran; Kalbasi, Mahmoud; Shariatmadari, Hosein; Nourbakhsh, Farshid; Najafi, Bijan

2006-12-01

394

Negative hysteresis effect observed during calibration of the US Bureau of Mines borehole deformation gauge  

SciTech Connect

The US Bureau of Mines borehole deformation gauge (BMG) was designed in the early 1960`s to allow rock stress measurements by the overcoring method. Since that time it has become a de facto standard against which the performance of other borehole deformation gauges is often judged. However, during recent in situ stress studies in the Climax Stock at the Nevada Test Site a strange "negative hysteresis" in the order of 300 to 500 microstrains was observed in standard calibration data. Here, the relaxation curve lies below the indentation (compression) curves as if the system were to somehow respond with an energy release. Therefore, a precision micro-indentation apparatus has been designed and used to perform a series of tests allowing a better understanding of the BMG button to cantilever interaction. Results indicate that the hysteresis effect is caused by differential motion between the button base and the cantilever resulting from the geometric motion inherent in the cantilever. The very large apparent hysteresis is mainly caused by cycling opposing cantilevers through the instrument`s entire dynamic range, and the fundamental imprecision inherent in use of the standard micrometers to calibrate the BMG. Laboratory mean hysteresis magnitudes for a polished cantilever typically range from 3 to 25 microstrain for 100 and 1000 microstrain relaxations on 1000 microstrain deflection loops intended to simulate typical field data. The error percentage is thought to remain fairly constant with deformation loop size, and is sufficiently small such that it can be safely ignored. The hysteresis effect can probably be reduced, and instrument stability improved by machining a small 90 degree cone in the cantilever in which a slightly larger mating cone on the base of the indentation button would reside. 5 refs. 26 figs., 1 tab.

Ganow, H.C.

1985-08-01

395

An isotope exchange technique to assess mechanisms of sorption hysteresis applied to naphthalene in kerogenous organic matter.  

PubMed

The sorption of organic compounds to natural sorbents is often found to show hysteresis. The objective of this study was to develop an experimental technique based on the use of 14C isotopes to distinguish hysteresis due to experimental artifacts from true hysteresis due to thermodynamically irreversible processes. The study was also designed to investigate causation of true hysteresis (irreversible sorption). The technique determines the rates and the degree of isotope exchange (IE) on equilibrated sorption and desorption points at different constant bulk chemical concentrations. The technique was applied to the sorption of naphthalene (NAPH) on Beulah-Zap lignite, a low rank reference coal composed mainly of kerogen. Sorption of bulk was found to be reversible below 10(-5) g L(-1), but irreversible above 10(-4) g L(-1). Complete isotope exchange on sorption and desorption points that defined an irreversible cycle demonstrated that hysteresis was true. A comparison of normalized uptake and release kinetics of labeled and bulk NAPH at different concentrations revealed slow structural deformation processes of the sorbent during bulk sorption and desorption. This is taken as corroborating evidence for the pore deformation hypothesis of hysteresis in which incoming sorbate molecules induce quasi-reversible changes in the organic matter that lead to different pathways for sorption and desorption. Although unable to rule it out completely, the data demonstrate that physical entrapment of sorbate molecules plays a minor, if any, role to the observed hysteresis in this system. PMID:16245818

Sander, Michael; Pignatello, Joseph J

2005-10-01

396

Monitoring the hysteresis effects in the strain-stress curve of carbon fiber reinforced laminates by FBG technology  

NASA Astrophysics Data System (ADS)

In this paper, we present a study of detecting the hysteresis effect in strain-stress curve of carbon fiber reinforced materials by Fiber Bragg Grating technology. By calculating the dissipative energy density contoured by hysteresis loops, this method can be further applied in detecting the cracks and fatigue of carbon fiber reinforced laminates. In contrast to the traditional sensors, such FBG sensors have numerous merits, such as small size, immunity to Electromagnetic Interference and easy installation into the carbon fiber reinforced laminates. This method can also be extended into monitoring other materials which also exhibit hysteresis effects in their strain-stress curves.

Zhang, Hongtao; Ghandehari, Masoud; Sidelev, Alexey; Bazhanski, Ruslan; Wang, Pengfei; Xie, Jing; Zou, Jilin; Lui, Engui; Li, David; Fang, Fang; Cui, Hong-Liang; Wang, Xingwei

2011-05-01

397

Hysteresis reduction by fluorine incorporation into high permittivity tetragonal ZrO2 on Ge  

NASA Astrophysics Data System (ADS)

Utilizing remote NH3/H2 plasma on GeO2/Ge can achieve the nearly-free interfacial layer and low equivalent oxide thickness of ˜0.4 nm by the formation of tetragonal ZrO2 phase. However, the electrical defects in ZrO2 result in a large C-V hysteresis (˜580 mV). The fluorine incorporation by CF4 plasma is demonstrated to effectively passivate these defects both experimentally and theoretically. The hysteresis is reduced to be ˜200 mV, and the interface defect density, permittivity, and gate leakage current remain intact. The Zr-F bond formation to remove the midgap states calculated by the density-function-theory may be the origin of passivation.

Chang, Hung-Chih; Lin, Cheng-Ming; Huang, Chih-Hsiung; Liu, C. W.

2014-01-01

398

Domain Dynamics in Piezoresponse Force Microscopy: Quantitative Deconvolution and Hysteresis Loop Fine Structure  

SciTech Connect

Domain dynamics in the Piezoresponse Force Spectroscopy (PFS) experiment is studied using the combination of local hysteresis loop acquisition with simultaneous domain imaging. The analytical theory for PFS signal from domain of arbitrary cross-section is developed and used for the analysis of experimental data on Pb(Zr,Ti)O3 polycrystalline films. The results suggest formation of oblate domain at early stage of the domain nucleation and growth, consistent with efficient screening of depolarization field within the material. The fine structure of the hysteresis loop is shown to be related to the observed jumps in the domain geometry during domain wall propagation (nanoscale Barkhausen jumps), indicative of strong domain-defect interactions.

Bdikin, Igor [University of Aveiro, Portugal; Kholkin, Andrei [University of Aveiro, Portugal; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine; Svechnikov, S. V. [National Academy of Science of Ukraine, Kiev, Ukraine; Kim, S.-H. [INOSTEK Inc., Gyeonggi, Korea; Kalinin, Sergei V [ORNL

2008-01-01

399

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

SciTech Connect

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

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

1994-05-15

400

Magnetocaloric effect in the low hysteresis Ni-Mn-In metamagnetic shape-memory Heusler alloy  

NASA Astrophysics Data System (ADS)

We have studied magnetocaloric properties of a Ni-Mn-In metamagnetic shape-memory alloy especially designed in order to display low thermal hysteresis. Magnetization and calorimetric measurements under a magnetic field have been used in order to determine isothermal magnetic field-induced entropy changes. Results obtained indirectly from magnetization data, quasi-directly from isofield calorimetric measurements, and directly from isothermal calorimetric runs are systematic and agree well with each other. We have analyzed the reproducibility of magnetocaloric properties with cycling from direct isothermal calorimetric measurements. Due to low thermal hysteresis, we have found that about 80% of the transition entropy change, ?St ? 25 J/kg K, can be reversibly induced under successive application and removal of a field of 6 T.

Stern-Taulats, Enric; Castillo-Villa, Pedro O.; Mañosa, Lluís; Frontera, Carlos; Pramanick, Sabyasachi; Majumdar, Subham; Planes, Antoni

2014-05-01

401

Microstructures in Low-Hysteresis Shape Memory Alloys: Scaling Regimes and Optimal Needle Shapes  

NASA Astrophysics Data System (ADS)

For certain martensitic phase transformations, one observes a close relation between the width of the thermal hysteresis and the compatibility of two phases. This observation forms the basis of a theory of hysteresis that assigns an important role to the microstructures in the transition layer and their energetics (Zhang et al., Acta Mater 57(15), 4332-4352, 2009). We study microstructures for almost compatible phases in the context of nonlinear elasticity. Using a scalar valued ansatz we show that one expects a transition from uniform to branched patterns for various typical models of the surface energy. We subsequently consider needle-type transition layers and study quantitative differences between hard and soft austenite, and between twins of different martensitic variants.

Zwicknagl, Barbara

2014-08-01

402

Density hysteresis of heavy water confined in a nanoporous silica matrix.  

PubMed

A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We interpret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid-liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved. PMID:21746898

Zhang, Yang; Faraone, Antonio; Kamitakahara, William A; Liu, Kao-Hsiang; Mou, Chung-Yuan; Leão, Juscelino B; Chang, Sung; Chen, Sow-Hsin

2011-07-26

403

Noise in neural networks: thresholds, hysteresis, and neuromodulation of signal-to-noise.  

PubMed Central

We study a neural-network model including Gaussian noise, higher-order neuronal interactions, and neuromodulation. For a first-order network, there is a threshold in the noise level (phase transition) above which the network displays only disorganized behavior and critical slowing down near the noise threshold. The network can tolerate more noise if it has higher-order feedback interactions, which also lead to hysteresis and multistability in the network dynamics. The signal-to-noise ratio can be adjusted in a biological neural network by neuromodulators such as norepinephrine. Comparisons are made to experimental results and further investigations are suggested to test the effects of hysteresis and neuromodulation in pattern recognition and learning. We propose that norepinephrine may "quench" the neural patterns of activity to enhance the ability to learn details.

Keeler, J D; Pichler, E E; Ross, J

1989-01-01

404

Density hysteresis of heavy water confined in a nanoporous silica matrix  

PubMed Central

A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We interpret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid–liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved.

Zhang, Yang; Faraone, Antonio; Kamitakahara, William A.; Liu, Kao-Hsiang; Mou, Chung-Yuan; Leao, Juscelino B.; Chang, Sung; Chen, Sow-Hsin

2011-01-01

405

Density hysteresis of heavy water confined in a nanoporous silica matrix  

SciTech Connect

A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We inter- pret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved.

Zhang, Yang [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Kamitakahara, William [ORNL; Liu, Kao-Hsiang [National Taiwan University; Mou, Chung-Yuan [National Taiwan University; Leao, Juscelino B [ORNL; Chang, Sung C [ORNL; Chen, Sow-hsin H [ORNL

2011-01-01

406

Contact angle hysteresis of non-flattened-top micro/nanostructures.  

PubMed

A two-dimensional (2D) thermodynamic model is proposed to predict the contact angle (CA) and contact angle hysteresis (CAH) of different types of surface geometries, particularly those with asperities having nonflattened tops. The model is evaluated by micro/nano sinusoidal and parabolic patterns fabricated by laser ablation. These microstructures are analyzed thermodynamically through the use of the Gibbs free energy to obtain the equilibrium contact angle (CA) and contact angle hysteresis (CAH). The effects of the geometrical details of two types of microstructures on maximizing the superhydrophobicity of the nanopatterned surface are also discussed in an attempt to design surfaces with desired and/or optimum wetting characteristics. The analysis of the various surfaces reveals the important geometrical parameters that may lead to the lotus effect (high CA > 150° and low CAH < 10°) or petal effect (high CA > 150° and high CAH ? 10°). PMID:24588357

Moradi, Sona; Englezos, Peter; Hatzikiriakos, Savvas G

2014-03-25

407

Simultaneous fabrication of superhydrophobic and superhydrophilic polyimide surfaces with low hysteresis.  

PubMed

Polyimide is of great interest in the field of MEMS and microtechnology. It is often used for its chemical, thermal, mechanical, and optical properties. In this paper, an original study is performed on controlled variation of polyimide film wettability. A two-step microtexturing method is developed to transform hydrophilic polyimide surfaces into a superhydrophobic surface with low magnitude of hysteresis (?? ? 0° and contact angle ? ? 158°). This method is based on the conception of a new kind of fakir surface with triangular cross-section micropillars, the use of a two-scale roughening, and a C(4)F(8) coating. We demonstrate that the absence of hysteresis is related to a combination of two scales of structuring and the pillar shape. The technology that has been developed results in the simultaneous fabrication of adjacent superhydrophobic and superhydrophilic small areas, which allows an effect of self-positioning of water droplets when deposited on such a checkerboard-like surface. PMID:21520916

Scheen, Gilles; Ziouche, Katir; Bougrioua, Zahia; Godts, Pascale; Leclercq, Didier; Lasri, Tuami

2011-05-17

408

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

SciTech Connect

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

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

2009-04-15

409

Hysteresis and acoustic emission as non-destructive measures of the fatigue process in metals  

NASA Astrophysics Data System (ADS)

Metal fatigue is a result of a cumulative damage process due to repeated cyclic loading which causes premature and unpredictable failure. It is a complicated metallurgical process at the microscopic level which is difficult to accurately explain or model. Despite the complexities, fatigue analysis methods have been developed and are being developed to facilitate fatigue damage assessment and the prediction of fatigue life. This research project is concerned with the behavior of metals subjected to cyclic loading carried to failure. The purpose of this investigation is to develop a relationship between hysteresis loss, hysteresis loop drift, strain amplitudes, and the number of cycles to failure and to correlate this phenomenological description of the fatigue process with mesoscopic observables such as acoustic emission and stress-induced magnetization.

Guralnick, S. A.

1995-03-01

410

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

411

An implicit method for the nonlinear modelling and simulation of piezoceramic actuators displaying hysteresis  

NASA Technical Reports Server (NTRS)

Experiments have shown that piezoceramic materials display a nonlinear relationship between the applied electric field and the actuation strain. This relationship also displays a substantial hysteresis upon reversal of the applied field. In this paper, piezoceramic actuator models are incorporated into the structural equations of motion to arrive at a set of nonlinear actively controlled structural equations of motion. A new implicit algorithm for determining the time history of the actively controlled structure is presented. The algorithm employs the trapezoidal rule for stepping the equations forward in time. The algorithm is compared to an explicit algorithm and is shown to provide greater numerical accuracy. In addition, the numerical stability and convergence characteristics are presented via example. The new algorithm displays convergence and stability properties that are comparable to the standard trapezoidal rule used for dynamic systems without hysteresis.

Leigh, Timothy D.; Zimmerman, David C.

1991-01-01

412

Hysteresis and return-point memory in colloidal artificial spin ice systems.  

PubMed

Using computer simulations, we investigate hysteresis loops and return-point memory for artificial square and kagome spin ice systems by cycling an applied bias force and comparing microscopic effective spin configurations throughout the hysteresis cycle. Return-point memory loss is caused by motion of individual defects in kagome ice or of grain boundaries in square ice. In successive cycles, return-point memory is recovered rapidly in kagome ice. Memory is recovered more gradually in square ice due to the extended nature of the grain boundaries. Increasing the amount of quenched disorder increases the defect density but also enhances the return-point memory since the defects become trapped more easily. PMID:23005762

Libál, A; Reichhardt, C; Olson Reichhardt, C J

2012-08-01

413

Finite-set model predictive control of a flying capacitor converter with hysteresis voltage balancing  

Microsoft Academic Search

This paper presents a predictive strategy for current control of a three-phase flying capacitor converter. Future values of the load current and flying capacitor voltages are predicted with discrete-time system models. An offline solution for obtaining the best one of the 19 possible voltage vectors is combined with a hysteresis-based voltage balancing algorithm which makes use of the redundancy of

Peter Stolze; Peter Landsmann; Ralph Kennel; Toit Mouton

2011-01-01

414

Hysteresis effects and long-period oscillations of the D 2 NO reaction on Rh(110)  

Microsoft Academic Search

The reaction of D2 with NO on Rh(110) was studied by means of quadrupole mass spectrometry in combination with work function measurements (??) and low-energy electron diffraction (LEED). A strong hysteresis of the D2O production was found in the temperature range between 650 and 1050 K. This effect was most pronounced for a partial pressure ratio D2NO = 1.2 at

S. Heinze; V. Schmatloch; N. Kruse

1995-01-01

415

Lithium insertion and extraction for high-capacity disordered carbons with large hysteresis  

Microsoft Academic Search

Disordered carbons heat-treated from 550 to 1000 °C containing hydrogen atoms showed high specific capacities with large hysteresis in the potential when used as anodes in lithium-ion cells. The lithium storage mechanism in the disordered carbons has been investigated by the charge-discharge test, X-ray diffraction (XRD) and solid-state 7Li NMR measurements. Variation of the layer spacing of the disordered carbon

Norio Takami; Asako Satoh; Takahisa Ohsaki; Motoya Kanda

1997-01-01

416

Color-gradient lattice Boltzmann model for simulating droplet motion with contact-angle hysteresis.  

PubMed

Lattice Boltzmann method (LBM) is an effective tool for simulating the contact-line motion due to the nature of its microscopic dynamics. In contact-line motion, contact-angle hysteresis is an inherent phenomenon, but it is neglected in most existing color-gradient based LBMs. In this paper, a color-gradient based multiphase LBM is developed to simulate the contact-line motion, particularly with the hysteresis of contact angle involved. In this model, the perturbation operator based on the continuum surface force concept is introduced to model the interfacial tension, and the recoloring operator proposed by Latva-Kokko and Rothman is used to produce phase segregation and resolve the lattice pinning problem. At the solid surface, the color-conserving wetting boundary condition [Hollis et al., IMA J. Appl. Math. 76, 726 (2011)] is applied to improve the accuracy of simulations and suppress spurious currents at the contact line. In particular, we present a numerical algorithm to allow for the effect of the contact-angle hysteresis, in which an iterative procedure is used to determine the dynamic contact angle. Numerical simulations are conducted to verify the developed model, including the droplet partial wetting process and droplet dynamical behavior in a simple shear flow. The obtained results are compared with theoretical solutions and experimental data, indicating that the model is able to predict the equilibrium droplet shape as well as the dynamic process of partial wetting and thus permits accurate prediction of contact-line motion with the consideration of contact-angle hysteresis. PMID:24229303

Ba, Yan; Liu, Haihu; Sun, Jinju; Zheng, Rongye

2013-10-01

417

Color-gradient lattice Boltzmann model for simulating droplet motion with contact-angle hysteresis  

NASA Astrophysics Data System (ADS)

Lattice Boltzmann method (LBM) is an effective tool for simulating the contact-line motion due to the nature of its microscopic dynamics. In contact-line motion, contact-angle hysteresis is an inherent phenomenon, but it is neglected in most existing color-gradient based LBMs. In this paper, a color-gradient based multiphase LBM is developed to simulate the contact-line motion, particularly with the hysteresis of contact angle involved. In this model, the perturbation operator based on the continuum surface force concept is introduced to model the interfacial tension, and the recoloring operator proposed by Latva-Kokko and Rothman is used to produce phase segregation and resolve the lattice pinning problem. At the solid surface, the color-conserving wetting boundary condition [Hollis , IMA J. Appl. Math.IJAMDM0272-496010.1093/imamat/hxr008 76, 726 (2011)] is applied to improve the accuracy of simulations and suppress spurious currents at the contact line. In particular, we present a numerical algorithm to allow for the effect of the contact-angle hysteresis, in which an iterative procedure is used to determine the dynamic contact angle. Numerical simulations are conducted to verify the developed model, including the droplet partial wetting process and droplet dynamical behavior in a simple shear flow. The obtained results are compared with theoretical solutions and experimental data, indicating that the model is able to predict the equilibrium droplet shape as well as the dynamic process of partial wetting and thus permits accurate prediction of contact-line motion with the consideration of contact-angle hysteresis.

Ba, Yan; Liu, Haihu; Sun, Jinju; Zheng, Rongye

2013-10-01

418

Investigation of the hysteresis phenomena in steady shock reflection using kinetic and continuum methods  

NASA Astrophysics Data System (ADS)

The problem of transition of planar shock waves over straight wedges in steady flows from regular to Mach reflection and back was numerically studied by the DSMC method for solving the Boltzmann equation and finite difference method with FCT algorithm for solving the Euler equations. It is shown that the transition from regular to Mach reflection takes place in accordance with detachment criterion while the opposite transition occurs at smaller angles. The hysteresis effect was observed at increasing and decreasing shock wave angle.

Ivanov, M.; Zeitoun, D.; Vuillon, J.; Gimelshein, S.; Markelov, G.

1996-05-01

419

A limitation of hysteresis in the correction of the sextupole field in a magnetic quadrupole lens  

NASA Astrophysics Data System (ADS)

Parasitic sextupole fields present in magnetic quadrupole lenses can be corrected by shunting the current flowing through one or two adjacent pole piece coils. It is shown here that this procedure can be limited by hysteresis in the quadrupole lens. This means that the sextupole field strength and also the size of the current shunts required to correct it depend on the direction of the current flow in the lens.

Breese, M. B. H.; Swietlicki, E.; Pallon, J.

1993-12-01

420

Hysteresis Current Control and Sensorless MPPT for Grid-Connected Photovoltaic Systems  

Microsoft Academic Search

This paper describes a control method for single-phase transformerless grid-connected inverter system for photovoltaic (PV) application. The system consists of a DC-DC Boost Converter and a full-bridge inverter. The DC-DC Boost Converter implements a Sensorless Maximum Power Point Tracker (MPPT) algorithm with regulated DC bus voltage while the full-bridge inverter implements a Hysteresis Current Control as the control method. These

Nasrudin Abd Rahim; J. Selvaraj; Krismadinata

2007-01-01

421

Simulation of thermomechanical and electrothermal hysteresis phenomena in porous nickel titanium  

NASA Astrophysics Data System (ADS)

There is represented a general scheme of functioning and the corresponding model of a porous biomicrofluid matrix based on nickel titanium, which possesses a shape-memory effect, prepared by the method of selective laser sintering. The simulation of thermomechanical and electrothermal hysteresis phenomena composes the basis of the functioning of this MEMS. Such a model can be used for estimating the efficiency and controllability of drug delivery systems via the change in the volume of pores.

Shishkovsky, I. V.

2014-02-01

422

Hysteresis and reaction characterization of methane catalytic partial oxidation on rhodium catalyst  

Microsoft Academic Search

Hysteresis effects and reaction characteristics of methane catalytic partial oxidation (CPO) in a fixed-bed reactor are numerically simulated. The reactions are modeled based on the experimental measurements of methane CPO with a rhodium (Rh) catalyst. Three C\\/O ratios of 0.6, 1.0 and 1.4 are considered in the study. When the Reynolds number is 200, the predictions indicate that the methane

Wei-Hsin Chen; Tin-Wei Chiu; Chen-I Hung; Mu-Rong Lin

2009-01-01

423

Constitutive model of shape memory alloys for unidirectional loading considering inner hysteresis loops  

Microsoft Academic Search

A specimen-based macroscopic constitutive model of shape memory alloys for unidirectional loading, which is simple yet accurate and has a physical background, was derived from a grain-based microscopic model. To consider the inner hysteresis loops of a stress-strain-temperature relationship, a new inner loop model called the shift and skip model was proposed. This model is based on microscopic aspects and

Tadashige Ikeda; Florin Andrei Nae; Hisashi Naito; Yuji Matsuzaki

2004-01-01

424

One-dimensional quasistatic nonisothermal evolution of shape-memory material inside the hysteresis loop  

Microsoft Academic Search

We study in this paper the quasistatic nonisothermal processes of a onedimensional bar consisting of a two-phase shape-memory material. The system of p.d.e.'s governing the evolution of the bar is obtained by means of a temperature-dependent hysteretic stress-strain law that we formulate as a “plasticity” criterion and a hysteresis operator. The constitutive theory is developed here on the basis of

B. Fedelich; G. Zanzotto

1991-01-01

425

Pinholes in antiferromagnetically coupled multilayers: Effects on hysteresis loops and relation to biquadratic exchange  

Microsoft Academic Search

We present a micromagnetic study of the influence of ferromagnetic bridges between consecutive ferromagnetic layers in antiferromagnetically coupled multilayers. The model is compared with experimental results for hysteresis loops obtained from the multilayer systems Co-Cu and FeNi-Ag. The presence of pinholes in Cu-Co multilayers is confirmed by transmission electron microscopy. We demonstrate that low densities of ferromagnetic pinholes in such

J. F. Bobo; H. Kikuchi; O. Redon; E. Snoeck; M. Piecuch; R. L. White

1999-01-01

426

A Theory of DE Hysteresis Loop Based on the Avrami Model  

Microsoft Academic Search

The D-E hysteresis loop of ferroelectrics is theoretically studied on the basis of the extended Avrami theory. If the sideway velocity depends only on the instant value of the applied field, the volume fraction of the reversed area is expressed as q(E)=1-exp (-f-dPhi(E)), where f and d are, respectively, the frequency of the applied field and the growth dimension of

Hiroshi Orihara; Shigeharu Hashimoto; Yoshihiro Ishibashi

1994-01-01

427

Hysteresis loops and the inelastic deformation of 0\\/90 ceramic matrix composites  

Microsoft Academic Search

Hysteresis measurements obtained on 0\\/90 SiC\\/CAS and SiC\\/SiC have been used to analyze the interface responses. Four parameters have been derived from these measurements. These relate to the compliance change caused by matrix cracking, the frictional resistance of the interface, the interface debond resistance, and the residual stress. These parameters have been used to predict the stress\\/strain curves. Preliminary estimates

Jean-Marc Domergue; Fernando E. Heredia; Anthony G. Evans

1996-01-01

428

Three level hysteresis current controller based active power filter for harmonic compensation  

Microsoft Academic Search

This paper present three-phase four-wire active filter for power line conditioning (PLC) to improve power quality in the distribution network. The active power filter (APF) is implemented with PWM based current controlled voltage source inverter (VSI). This VSI switching signals are generated through proposed three-level hysteresis current controller (HCC) that achieves significant reduction in the magnitude and variation of the

P Karuppanan; Saswat Kumar Ram; KamalaKanta Mahapatra

2011-01-01

429

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

Microsoft Academic Search

At a transformer's steady-state condition, whereby a transformer and its load are constantly supplied by a sinusoidal source, the current-flux pair within the transformer core and its windings will cycle along a hysteresis loop. This nonlinear current-flux characteristic becomes important while at transformer gets reenergized. A remaining residual flux and the fact that a transformer is typically used up to

Yves Corrodi; Kenji Kamei; Haruhiko Kohyama; Hiroki Ito

2010-01-01

430

Harmonic modeling of single-phase three-level hysteresis inverters  

Microsoft Academic Search

The paper derives a closed-form analytical approximation of the output current harmonic spectrum for the three-level single-phase inverters under the action of hysteresis current control. The error current harmonic spectrum is directly calculated from the system and controller parameters. The analytical approach consists of deriving the instantaneous frequency of the error current and then approximating the error current by a

Ahmad Albanna; C. J. Hatziadoniu

2009-01-01

431

Origin of hysteresis in the transfer characteristic of carbon nanotube field effect transistor  

NASA Astrophysics Data System (ADS)

Using electrostatic force microscopy, we show direct evidence of charge injection at the carbon nanotube-SiO2 interface leading to the appearance of hysteresis. The dynamic screening effect of the injected charges is revealed step by step. Further temperature dependent tests also demonstrate the effect of SiO2 surface chemistry. Furthermore, we conclude that it is not practical to use such a device for memory application because of data retention and storage density issues.

Ong, H. G.; Cheah, J. W.; Zou, X.; Li, B.; Cao, X. H.; Tantang, H.; Li, L.-J.; Zhang, H.; Han, G. C.; Wang, J.

2011-07-01

432

Strong-weak network anisotropy switching and hysteresis in three-dimensional granular materials  

Microsoft Academic Search

We address hysteresis of three-dimensional polydisperse granular packs, comparing macro- and microscopic viewpoints, to reveal their elastic\\/inelastic mechanics and force network anisotropy. During the uniaxial loading-unloading cycle of an appropriately prepared pack, one can decompose the force network into weak and strong subnetworks. The first stages of loading exhibit arching, where all the fabric displays negative anisotropy. For later stages,

Xavier García; Ernesto Medina

2008-01-01

433

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

Microsoft Academic Search

We present an extensive thermodynamic analysis of a hysteresis experiment\\u000aperformed on a simplified yet Earth-like climate model. We slowly vary the\\u000asolar constant by 20% around the present value and detect a substantial\\u000abistability: for a large range of values the realization of snowball (SB) or of\\u000awarm (W) climate conditions depend on the history of the system. Using

Klaus Fraedrich; Frank Lunkeit

2009-01-01

434

Optical hysteresis and nonlinear absorption of laser pulses in aAs2S3  

Microsoft Academic Search

Results of the experimental investigations of the nonlinear absorption of microsecond laser pulses in thin amorphous As2S3 films are presented. The optical transmission hysteresis at interband excitation of As2S3 films in a blue-green spectral region is reported for the first time. A reversible film photodarkening induced in the field of laser pulses was registered. It was suggested that the interband

Valentin N. Chumash; G. Bostan; I. Cojocaru; P. Cerbari

1995-01-01

435

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

Microsoft Academic Search

(1) The partitioning between solid and aqueous phases of tropospheric sulfate-ammonium particles is simulated with a global 3-D chemical transport model (CTM). The simulation explicitly accounts for the hysteresis of particle phase transitions by transporting aqueous sulfate and three solid sulfate forms (namely, ammonium sulfate, letovicite, and ammonium bisulfate). Composition-dependent deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) are

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

2008-01-01

436

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

Microsoft Academic Search

The partitioning between solid and aqueous phases of tropospheric sulfate-ammonium particles is simulated with a global 3-D chemical transport model (CTM). The simulation explicitly accounts for the hysteresis of particle phase transitions by transporting aqueous sulfate and three solid sulfate forms (namely, ammonium sulfate, letovicite, and ammonium bisulfate). Composition-dependent deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) are based

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

2008-01-01

437

A Investigation of the Dielectric and Hysteresis Properties of Plzt Ferroelectric and Multilayer Composite Thin Films.  

NASA Astrophysics Data System (ADS)

The dielectric and hysteresis properties of ferroelectric and multilayer composite thin films were investigated. PLZT ferroelectrics were produced in bulk ceramic and thin film form from the same acetate precursor solutions in order to compare their electrical and physical properties. Bulk ceramics were hot pressed from chemically coprecipitated powders, and thin films were fabricated by spin and dip coating on Ag and Pt-coated Si substrates. Internal film stress from thermal expansion mismatch between films and substrates was found to contribute to differences in electrical properties and Curie temperatures between the thin film and bulk materials as were interface layer effects, grain size and mechanical clamping from the substrates. Rapid thermal processing (RTP) of PLZT thin films using an automated spin coat reactor was found to improve thin film dielectric and hysteresis properties as well as enhance perovskite phase formation, induce preferred (110) and (111) orientations, decrease grain size and increase microstructural uniformity. RTP films were compared with manually spin coated thin films with conventional furnace pyrolysis (CFP) in order to isolate the effects of heating rate from deposition technique. Heating rates of at least 70^circC per second were obtained by RTP versus 35^circC per second for CFP. The development of composite thin films further optimized PLZT thin film properties. Improved antiferroelectric -to-ferroelectric domain switching with decreased ferroelectric coercive field, increased induced polarization with decreased coercivity and polarization remanence for relaxor-type composites and increased hysteresis loop squareness for ferroelectric memory materials were among the advances compared with films of homogeneous PLZT composition. Experimental dielectric and hysteresis properties were described by a series capacitor model consisting of the linear and nonlinear properties of the individual composite components.

Dausch, David Edward

1995-01-01

438

Anomalous thermal hysteresis in dielectric permittivity of CaCu3Ti4O12  

Microsoft Academic Search

We herein report an anomalous thermal hysteresis in dielectric permittivity in CaCu3Ti4O12. The anomalous behavior was well explained in terms of the low-temperature Maxwell-Wagner relaxation induced by frozen carriers. A multirelaxation mechanism, i.e., the coupling of the dipole relaxation to the frozen carrier-induced and blocked carrier-induced Maxwell-Wagner relaxations in the low-temperature and high-temperature regions, respectively, is proposed to be the

C. C. Wang; L. W. Zhang

2008-01-01

439

Analysis of Hysteresis Damage Accumulation and the Effect on Fatigue Life  

Microsoft Academic Search

\\u000a In order to validate an existing energy-based fatigue life prediction understanding, the strain energy accumulation for interrupted\\u000a loading cycles was analyzed. The life prediction method being validated was developed based on the understanding that strain\\u000a energy density accumulated during monotonic fracture is a physical damage quantity that is equal to total cumulative hysteresis\\u000a strain energies in a fatigue process. If

Onome Scott-Emuakpor; Tommy George; Charles Cross; M.-H. Herman Shen

440

Magnetic properties modeling of soft magnetic composite materials using two-dimensional vector hybrid hysteresis model  

NASA Astrophysics Data System (ADS)

A 2-D vector hybrid hysteresis model for a soft magnetic composite (SMC) material is established, which is combined with classical Preisach model and Stoner-Wohlfarth (S-W) model. The rotational magnetic properties of SMC materials were studied using the vector model, and the computed results were compared with the experimental measurement. It is shown that the vector hybrid model can effectively simulate the rotational magnetic properties under low magnetization fields.

Li, Dandan; Liu, Fugui; Li, Yongjian; Zhao, Zhigang; Zhang, Changgeng; Yang, Qingxin

2014-05-01

441

Low-power optical bistability and hysteresis in the laser system with absorbing nanosuspension.  

PubMed

We demonstrate an optical bistability in a laser system with incoherent optical feedback and a nanosuspension as a nonlinear element. The optical transfer function is shown to exhibit a hysteresis loop for the light power in the range of a few milliwatts. It has been found that the optical bistability relies on the incoherent optical feedback and thermal defocusing nonlinear optical response of the nanosuspension. PMID:24784112

Pobegalov, George; Agruzov, Peter; Ilichev, Igor; Shamray, Alexander

2014-05-01

442

Hydrological and Hysteresis Response of Open Lined Channels in Small Urban Residential Catchments in Singapore  

Microsoft Academic Search

Two small urban residential catchments, namely Jurong West (JW) (1 ha) and Ang Mo Kio (AMK) (0.6 ha) in Singapore have been selected as sites to investigate hysteresis patterns and hydrological responses from catchments' pervious surfaces and different types of impervious, namely directly connected impervious areas (DCIA) and non-directly connected impervious areas (Non-DCIA)during rain events. Results from February 2005 till

W. Lee

2005-01-01

443

Hysteresis and baseline shift in permanent magnet stabilized MR\\/SAL heads  

Microsoft Academic Search

Hysteresis and baseline shift in shielded permanent magnet stabilized MR\\/SAL playback heads are studied via a 3D micromagnetic simulation. The hysteretic behavior is examined by calculation of playback voltages and uniform field transfer curves. The overlap region between the MR\\/SAL layers and the permanent magnet is seen to have a strong effect on the stability of the device. The amount

Eric Champion; H. Neal Bertram

1996-01-01

444

Rotational hysteresis and training effect of ferro\\/antiferromagnetic exchange-coupled systems  

Microsoft Academic Search

This dissertation presents experimental results and explanations about two fundamental phenomena of ferromagnetic (F)\\/antiferromagnetic (AF) exchange coupled polycrystalline layer systems, i.e., the 360°-symmetry rotational hysteresis and the magnetic training effect. Various F\\/AF exchange coupled systems were prepared, studied and compared. The results imply that the direct exchange coupling between the AF grains is playing a decisive role in governing the

Kunliang Zhang

2002-01-01

445

Nature of dislocation hysteresis losses and nonlinear effect in lead at high vibration amplitudes  

SciTech Connect

The nature of the dislocation hysteresis was established and changes in this hysteresis were determined by investigating the dependence of the dislocation-induced absorption of ultrasound (coefficient ..cap alpha..) on the amplitude of ultrasound epsilon-c/sub 0/ in single crystals of pure lead and of lead containing Tl and Sn impurities. The investigation was carried out in a wide range of epsilon-c/sub 0/ under superconducting transition conditions. In the superconducting (s) state both pure Pb and that doped with T1 exhibited a maximum in the dependence ..cap alpha..(epsilon-c/sub 0/) at high values of epsilon-c/sub 0/; on transition to the normal (n) state this maximum changed to a plateau. This provided a direct proof of a change in the static nature of the dislocation hysteresis to the dynamic process because of an increase in the coefficient of the electron drag of dislocations. Estimates were obtained of the range of lengths of dislocation loops: 2.4 x 10/sup -4/ cmhysteresis occurred both in the normal and superconducting states. In the range of amplitudes above that of the maximum and at the beginning of the plateau all single crystals exhibited a rise of ..cap alpha.. on increase of epsilon-c/sub 0/ in the superconducting and normal states; this rise was due to nonlinear effects observed in the case of strong bending of L/sub N/ loops. An analysis was made of the amplitude dependence of the losses associated with this effect. The results were in good agreement with the experimental data.

Lomakin, V.V.; Pal-Val, L.N.; Platkov, V.Y.; Roshchupkin, A.M.

1982-11-01

446

Anomalous contact angle hysteresis of a captive bubble: advancing contact line pinning.  

PubMed

Contact angle hysteresis of a sessile drop on a substrate consists of continuous invasion of liquid phase with the advancing angle (?(a)) and contact line pinning of liquid phase retreat until the receding angle (?(r)) is reached. Receding pinning is generally attributed to localized defects that are more wettable than the rest of the surface. However, the defect model cannot explain advancing pinning of liquid phase invasion driven by a deflating bubble and continuous retreat of liquid phase driven by the inflating bubble. A simple thermodynamic model based on adhesion hysteresis is proposed to explain anomalous contact angle hysteresis of a captive bubble quantitatively. The adhesion model involves two solid–liquid interfacial tensions (?(sl) > ?(sl)?). Young’s equation with ?(sl) gives the advancing angle ?(a) while that with ?(sl)? due to surface rearrangement yields the receding angle ?(r). Our analytical analysis indicates that contact line pinning represents frustration in surface free energy, and the equilibrium shape corresponds to a nondifferential minimum instead of a local minimum. On the basis of our thermodynamic model, Surface Evolver simulations are performed to reproduce both advancing and receding behavior associated with a captive bubble on the acrylic glass. PMID:21545100

Hong, Siang-Jie; Chang, Feng-Ming; Chou, Tung-He; Chan, Seong Heng; Sheng, Yu-Jane; Tsao, Heng-Kwong

2011-06-01

447

Inkjet printing of precisely defined features using contact-angle hysteresis.  

PubMed

Motivated by the process of inkjet printing of electronics, we study experimentally and theoretically the processes limiting the printing of sharply defined, equilibrium corners. Using a non-volatile ionic liquid, we inkjet print squares with rounded corners on a substrate of roughened, display-grade glass. We show experimentally that with increasing roughness, corner radius decreases, allowing more precisely defined features to be printed. To interpret these results in terms of contact-angle hysteresis (difference between the advancing and retreating contact angles ?A and ?R), we implement the following model with the Surface Evolver program. With drop volume fixed, we minimize drop surface energy subject to a prescribed contact line. We identify ?A and ?R as the minimum and maximum contact angles around the drop perimeter. We find that with decreasing corner fidelity, contact-angle hysteresis also decreases. We are thus able to infer ?R from the corner radius of printed features. We conclude that increasing contact-angle hysteresis allows the printing of more precisely defined features. PMID:23570870

Soltman, Dan; Smith, Ben; Morris, S J S; Subramanian, Vivek

2013-06-15

448

Transport, phase reactions, and hysteresis of iron fluoride and oxyfluoride conversion electrode materials for lithium batteries.  

PubMed

Potentiostatic intermittent titration technique (PITT) was applied to FeF2, FeF3, and FeO0.67F1.33 to gain insight into the transport-related aspects of the conversion reaction by quantitative analysis of Li(+) diffusion and hysteresis. PITT derived diffusion coefficient measurements were benchmarked relative to values extracted by electrochemical impedance spectroscopy (EIS). A reverse-step PITT methodology was used to evaluate true hysteresis by eliminating nucleation induced overpotentials. This method evaluates the minimum potential hysteresis and allowed an accurate representation of the potential required to move conversion reactions forward at C/1000 rates in both lithiation and delithiation. The high resolution PITT data were also used to gain further insight into reaction mechanisms involved in the reversible conversion reactions. Physical evidence, based on pair distribution function (PDF) structural analysis, and electrochemical evidence are presented regarding a new step in the reaction during the rutile FeF2 reconversion reaction. PMID:24708435

Ko, Jonathan K; Wiaderek, Kamila M; Pereira, Nathalie; Kinnibrugh, Tiffany L; Kim, Joshua R; Chupas, Peter J; Chapman, Karena W; Amatucci, Glenn G

2014-07-23

449

Hysteresis and reluctance electric machines with bulk HTS elements. Recent results and future development  

NASA Astrophysics Data System (ADS)

Two new types of HTS electric machine are considered. The first type is hysteresis motors and generators with cylindrical and disc rotors containing bulk HTS elements. The second type is reluctance motors with compound HTS-ferromagnetic rotors. The compound HTS-ferromagnetic rotors, consisting of joined alternating bulk HTS (YBCO) and ferromagnetic (iron) plates, provide a new active material for electromechanical purposes. Such rotors have anisotropic properties (ferromagnetic in one direction and diamagnetic in the perpendicular one). Theoretical and experimental results for HTS hysteresis and reluctance motors are presented. A series of hysteresis HTS motors with output power rating from 1 kW (at 50 Hz) up to 4 kW (at 400 Hz) and a series of reluctance HTS motors with output power 2-18.5 kW (at 50 Hz) were constructed and successfully tested. It was shown that HTS reluctance motors could reach two to five times better overall dimensions and specific power than conventional asynchronous motors of the same size and will have higher values of power factor (cos ??0.7 to 0.8).

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

2000-05-01

450

Vapour liquid coexisting curves and hysteresis of simple adsorbate in complex porous systems  

NASA Astrophysics Data System (ADS)

A unified approach for simulation of the vapour-liquid coexisting curves on phase diagrams and hysteresis phenomena for simple adsorbates in various type porous adsorbents was developed on the basis of the lattice-gas model. The ideas of this model in complex porous systems were used twice: for a construction of the over-molecular structure for high-dispersed bodies and for a description of the molecular distribution within the complex porous space. The supramolecular structure of these systems is modelled by sections with a simple regular geometry (slit-like, cylindrical and spherical) with additional inclusion of junctions between different pore sections. At the description of the adsorbate distribution, the lateral interactions between the fluidic molecules were included through the quasi-chemical approximation (QCA) that takes into account direct pair correlations between interacting molecules. The knowledge of phase diagrams allows improving a description of the adsorption hysteresis phenomena. The lattice-gas model enables explaining the experimental data for MCM-41 like sample in which the hysteresis is absent, when the pore size is narrowed more than ˜4 nm.

Tovbin, Yu. K.; Yeremich, D. V.; Zhidkova, L. K.

2005-10-01

451

Hysteresis force loss and damping properties in a practical magnet superconductor maglev test vehicle  

NASA Astrophysics Data System (ADS)

In order to investigate the feasible application of a permanent magnet-high-temperature superconductor (PM-HTS) interaction maglev system to a maglev train or a space vehicle launcher, we have constructed a demonstration maglev test vehicle. The force dissipation and damping of the maglev vehicle against external disturbances are studied in a wide range of amplitudes and frequencies by using a sine vibration testing set-up. The dynamic levitation force shows a typical hysteresis behavior, and the force loss is regarded as the hysteresis loss, which is believed to be due to flux motions in superconductors. In this study, we find that the hysteresis loss has weak frequency dependence at small amplitudes and that the dependence increases as the amplitude grows. To analyze the damping properties of the maglev vehicle at different field cooling (FC) conditions, we also employ a transient vibration testing technique. The maglev vehicle shows a very weak damping behavior, and the damping is almost unaffected by the trapped flux of the HTSs in different FC conditions, which is believed to be attributed to the strong pinning in melt-textured HTSs.

Yang, Wenjiang; Liu, Yu; Wen, Zheng; Chen, Xiaodong; Duan, Yi

2008-01-01

452

Modeling concentration-dependent sorption-desorption hysteresis of atrazine in a loam soil.  

PubMed

Nonequilibrium sorption plays an active role in the transport of organic contaminants in soil. We applied a two-stage, one-rate model (2S1R) and a new, nonlinear variant (2S1RN) of this model to examine the effects of wastewater irrigation on the sorption kinetics of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in soil. The models were applied to previously published sorption-desorption data sets, which showed pronounced deviations between sorption curves and desorption curves (sorption-desorption hysteresis). Moreover, the slopes of the desorption curves decreased with decreasing concentration. Different treatments had been used, and two experimental time steps (2 and 14 d) were used. Treatments considered were lipid removal, fulvic and humic acid removal, and untreated soil. The 2S1R model was unable to reproduce the observed type of hysteresis, but the 2S1RN model, which assumes that the sorption-desorption process follows a power function relationship, was able to reproduce the observed type of hysteresis. Visually, applying the new model improved the model fits in all test cases. Statistically, as tested by an extra sum of squares analysis, the new model performed significantly better in 50% of all test cases. According to an example simulation, the choice of the sorption model has a considerable impact on the prediction of atrazine transport in soil. PMID:21520761

Anagu, Ihuaku; Ingwersen, Joachim; Drori, Yaron; Chefetz, Benny; Streck, Thilo

2011-01-01

453

Effect of Hysteresis on Measurements of Thin-Film Cell Performance  

SciTech Connect

Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (Voc), up to 10 mV, and smaller short-circuit current density (Jsc), by up to 2 mA/cm2, relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be as large as 3%. When Cu is not added, hysteresis in both Voc and Jsc is negligible however Pmax hysteresis is considerably greater. This behavior corroborates observed changes in depletion width, Wd, derived from capacitance (C) vs voltage (V) scans. Measured values of Wd are always smaller in reverse-to-forward voltage scans, and conversely, larger in the forward-to-reverse voltage direction. Transient ion drift (TID) measurements performed on Cu-containing cells do not show ionic behavior suggesting that capacitance transients are more likely due to electronic capture-emission processes. J-V curve simulation using Pspice shows that increased transient capacitance during light-soak stress at 100 degrees C correlates with increased space-charge recombination. Voltage-dependent collection however was not observed to increase with stress in these cells.

Albin, D.; del Cueto, J.

2011-03-01

454

Strong nonlinearity and hysteresis of Hall resistance versus magnetization in nickel thin films  

NASA Astrophysics Data System (ADS)

The anomalous Hall effect (AHE) in ferromagnetic materials is perhaps one of the oldest unresolved mysteries in physics. First observed in 1881, its mechanism is still a controversial topic today. The question remains whether AHE is caused by intrinsic (Berry phase and band structure) or extrinsic (defect scattering) effects or a combination of both. Here we present experimental observation in nickel thin films that seems to add to the mystery, but may in fact provide crucial clues for ultimately resolving the controversy. The key observation is that the Hall resistivity of nickel films is a strongly nonlinear function of the magnetization and displays clear hysteresis with respect to M. Specifically, at low temperatures, the anomalous Hall coefficient switches between two saturated values under the magnetic field with a narrow transition region, but with a strong hysteresis, in contrast to the slow saturation of the magnetization. The nonlinearity and the hysteresis become more apparent with decreasing temperature or film thickness. Despite the simplicity of the lattice and magnetic structure of nickel films, these results are outside our current understanding of AHE, whether using intrinsic or extrinsic mechanisms of AHE. It presents a challenge for these models, and may be used as a test of validity for both types of theories.

Song, Xiaohui; Fan, Jie; Zhang, X.-G.; Zhang, Dianlin

2010-08-01

455

Dynamic magnetic hysteresis behavior and dynamic phase transition in the spin-1 Blume-Capel model  

NASA Astrophysics Data System (ADS)

The nature (time variation) of response magnetization m( wt) of the spin-1 Blume-Capel model in the presence of a periodically varying external magnetic field h( wt) is studied by employing the effective-field theory (EFT) with correlations as well as the Glauber-type stochastic dynamics. We determine the time variations of m( wt) and h( wt) for various temperatures, and investigate the dynamic magnetic hysteresis behavior. We also investigate the temperature dependence of the dynamic magnetization, hysteresis loop area and correlation near the transition point in order to characterize the nature (first- or second-order) of the dynamic transitions as well as obtain the dynamic phase transition temperatures. The hysteresis loops are obtained for different reduced temperatures and we find that the areas of the loops are decreasing with the increasing of the reduced temperatures. We also present the dynamic phase diagrams and compare the results of the EFT with the results of the dynamic mean-field approximation. The phase diagrams exhibit many dynamic critical points, such as tricritical (•), zero-temperature critical (Z), triple (TP) and multicritical (A) points. According to values of Hamiltonian parameters, besides the paramagnetic (P), ferromagnetic (F) fundamental phases, one coexistence or mixed phase region, (F+P) and the reentrant behavior exist in the system. The results are in good agreement with some experimental and theoretical results.

Deviren, Bayram; Keskin, Mustafa

2012-03-01

456

a Thermal Conduction Switch Based on Low Hysteresis Nitife Shape Memory Alloy Helical Springs  

NASA Astrophysics Data System (ADS)

Shape memory alloy (SMA) actuators possess an inherent property of sensing a change in temperature and delivering significant force against external loads through a shape change resulting from a temperature-induced phase transformation. The utilization of a reversible trigonal (R-phase) to cubic phase transformation in NiTiFe SMAs allows for this strain recovery to occur with reduced hysteresis between the forward and reverse transformations. However, the magnitude of the strain recovery associated with the R-phase transformation is lower than that of the monoclinic to cubic phase transformation. The use of helical springs can compensate for this design constraint as they produce significant stroke when compared to straight elements such as thin strips and wires. This work reports on the development and implementation of NiTiFe helical springs in a low-hysteresis thermal conduction switch for advanced spaceport applications associated with NASA's requirements for future lunar and Mars missions. Such a low-hysteresis thermal conduction switch can provide on-demand heat transfer between two reservoirs at different temperatures.

Krishnan, V. B.; Bewerse, C.; Notardonato, W. U.; Vaidyanathan, R.

2008-03-01

457

Nonequilibrium hysteresis and Wien effect water dissociation at a bipolar membrane  

NASA Astrophysics Data System (ADS)

As in electrochemical cyclic voltammetry, time-periodic reverse voltage bias across a bipolar membrane is shown to exhibit hysteresis due to transient effects. This is due to the incomplete depletion of mobile ions, at the junction between the membranes, within two adjoining polarized layers; the layer thickness depends on the applied voltage and the surface charge densities. Experiments show that the hysteresis consists of an Ohmic linear rise in the total current with respect to the voltage, followed by a decay of the current. A limiting current is established for a long period when all the mobile ions are depleted from the polarized layer. If the resulting high field within the two polarized layers is sufficiently large, water dissociation occurs to produce proton and hydroxyl traveling wave fronts which contribute to another large jump in the current. We use numerical simulation and asymptotic analysis to interpret the experimental results and to estimate the amplitude of the transient hysteresis and the water-dissociation current.

Conroy, D. T.; Craster, R. V.; Matar, O. K.; Cheng, L.-J.; Chang, H.-C.

2012-11-01

458

Hysteresis measurement of individual multilayered Fe-Ga/Cu nanowires using magnetic force microscopy  

NASA Astrophysics Data System (ADS)

We have investigated nano-scale magnetic structures to learn how magnetic behaviors differ from what is observed in bulk materials. In this study, we have measured the magnetic hysteresis of individual multilayered nanowire using a magnetic force microscopy (MFM). The nanowires were composed of low-aspect ratio segments of iron-gallium (Galfenol, Fe80Ga20) and copper layers. Individual wires were released from nano-porous anodized aluminum oxide (AAO) templates and separated from other nanowires to avoid significant interactions between nearby nanowires. In this experiment, structures with aspects ratios c/a of ~3 were studied. Different MFM phase magnitudes in response to the interaction of magnetic film coated MFM tips and Fe-Ga/Cu nanowire were observed as a function of applied external magnetic field (-850 Oe < H < 850 Oe). Amplitude differences between bright and dark responses in MFM images were used to demonstrate hysteresis. Coercivity measured was about 125 Oe, which is almost same as the coercivity value (~150 Oe) of a nanowire array measured with a vibrating sample magnetometer (VSM). When fields are applied perpendicular to the nanowires, the hysteresis loops sheared, indicating that the easy axis is along the nanowire axis. Remanence magnetizations of an individual nanowire and a nanowire array were compared to demonstrate inter-wire magnetostatic dipolar interaction.

Jin Park, Jung; Reddy, Madhukar; Stadler, Bethanie J. H.; Flatau, Alison B.

2013-05-01

459

Modeling of Voltage Hysteresis and Relaxation for HEV NiMH Battery  

NASA Astrophysics Data System (ADS)

SOC (State of Charge) estimation based battery management is essential for HEV (Hybrid Electric Vehicle) applications. SOC can be estimated by the relationship between OCV (Open Circuit Voltage) and SOC, which is based on Nernst equation, in combination with coulomb counting. However voltage hysteresis and relaxation make the measurement of OCV difficult. Measured OCV after charge (discharge) is higher (lower) than estimated OCV by Nernst equation, and is slowly relaxed with time constant from few minutes to few hours. In this paper, to express voltage hysteresis and relaxation, three layers model concerning Nickel active materials is proposed. A voltage gap between surface and inside of Nickel active materials is introduced, and voltage hysteresis is modeled as surface partial battery decides OCV of the whole battery. Voltage relaxation is also expressed as equalization between surface layer and relaxation layer with higher internal resistance. The statical and dynamical behavior of proposed model is confirmed through the experiments of 7.2V 6.5Ah NiMH battery module.

Ota, Yutaka; Hashimoto, Yoshihiro

460

Observations of hysteresis in solar cycle variations among seven solar activity indicators  

NASA Technical Reports Server (NTRS)

We show that smoothed time series of 7 indices of solar activity exhibit significant solar cycle dependent differences in their relative variations during the past 20 years. In some cases these observed hysteresis patterns start to repeat over more than one solar cycle, giving evidence that this is a normal feature of solar variability. Among the indices we study, we find that the hysteresis effects are approximately simple phase shifts, and we quantify these phase shifts in terms of lag times behind the leading index, the International Sunspot Number. Our measured lag times range from less than one month to greater than four months and can be much larger than lag times estimated from short-term variations of these same activity indices during the emergence and decay of major active regions. We argue that hysteresis represents a real delay in the onset and decline of solar activity and is an important clue in the search for physical processes responsible for changing solar emission at various wavelengths.

Bachmann, Kurt T.; White, Oran R.

1994-01-01

461

Disordered self assembled monolayer dielectric induced hysteresis in organic field effect transistors.  

PubMed

A memory device using an organic field effect transistor (OFET) with copper phthalocyanine (CuPc) as active material was fabricated and studied. For this purpose, SiO2 dielectric surface was modified with a disordered self assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) molecule which was found to induce large disorder in CuPc film thereby generating more traps for charge carriers. Drain current-drain voltage characteristics at zero gate voltage exhibited large hysteresis which was not observed in OFET devices with ordered OTS monolayer modified and unmodified SiO2 dielectrics. The extent of hysteresis and drain current on/off ratio, reading voltage etc. were found to be dependent on the sweep rate/step voltage employed during scanning. Highest hysteresis with on/off ratio of about 240 was obtained for an optimum step voltage of 2 V while it decreased with further reduction in the same. This was attributed to the longer scanning time leading to release of trapped carriers during forward scan itself. The OFET device was found to exhibit excellent memory retention capability where OFF and ON current measured for about 2 hours after stressing the device at write and erase voltages showed good retention of on/off ratio. PMID:24738406

Padma, N; Saxena, Vibha; Sudarsan, V; Rava, Harshil; Sen, Shaswati

2014-06-01

462

Effects of solvents and vacancies on the electrical hysteresis characteristics in regioregular poly(3-hexylthiophene) organic thin-film transistors  

NASA Astrophysics Data System (ADS)

The role of residual solvents and vacancies within poly(3-hexylthiophene) (P3HT) active layers, which are made from different boiling point (bp) solvents, on the electrical hysteresis characteristics of P3HT-based transistors was investigated. The improved electrical performance and reduced hysteresis of P3HT films, which are spin coated by high bp solvents, can be interpreted by superior crystalline quality and homogeneity and low vacancies. The hysteresis is dominated by the vacancy-related charge traps in the semiconductor created during film solidification and subsequence solvent evaporation. Furthermore, residual solvents, which initially occupied the vacancies, can contribute to conductivity of regioregular P3HT, thus altering electrical properties and smaller hysteresis.

Cheng, Horng-Long; Lin, Wei-Qi; Wu, Fu-Chiao

2009-06-01

463

Proposal of Hysteresis Characteristics Model in Seismic Response Analysis using Single-Degree-of-Freedom System for Wooden House  

NASA Astrophysics Data System (ADS)

We proposed a hysteresis characteristics model for a single-degree-of-freedom wooden house with a single spring to perform earthquake response analyses. We modified 'Takeda-Slip model' to represent performance of wooden houses. We decided model's parameters based on the results of shaking table tests and investigated whether seismic response analyses using the proposed model could reproduce the experimental results. We found that the seismic response analyses could reproduce the experimental results. We also investigated the method of deciding model's parameters based on characteristics of bearing walls composing a wooden house. We made hysteresis characteristics of a whole structure from combining hysteresis characteristics of each bearing wall, and compared them with the experimental and analytical results using hysteresis characteristics model based on the result of a shaking table test. We got similar results, so we found proposed 'modified Takeda-Slip model' was useful for seismic response analyses of wooden houses.

Iizuka, Hiroaki; Sakai, Yuki

464

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

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

465

Accurate torque control of a bi-directional magneto-rheological actuator considering hysteresis and friction effects  

NASA Astrophysics Data System (ADS)

This paper presents a novel type of magneto-rheological (MR) actuator called a bi-directional magneto-rheological (BMR) actuator and accurate torque control results considering both hysteresis and friction compensation. The induced torque of this actuator varies from negative to positive values. As a result, it can work as either a brake or a clutch depending on the scheme of current input. In our work, the configuration of the actuator as well as its driving system is presented first. Subsequently, a congruency hysteresis based (CBH) model to take account of the effect of the hysteresis is proposed. After that, a compensator based on this model is developed. In addition, the effect of dry friction, which exists inherently with MR actuators in general, is also considered. In order to assess the effectiveness of the hysteresis compensator, several experiments on modeling and control of the actuator with different waveforms are carried out.

Nguyen, Phuong-Bac; Choi, Seung-Bok

2013-05-01

466

Experimental Implementation of a Model-Based Inverse Filter to Attenuate Hysteresis in an Atomic Force Microscope.  

National Technical Information Service (NTIS)

This paper addresses the development and experimental validation of a model-based, open loop control design for mitigating the frequency-dependent effects of hysteresis in an atomic force microscope (AFM). The models are based on homogenized energy relati...

A. Hatch R. G. Smith T. De

2004-01-01

467

Strain accommodation and potential hysteresis of LiFePO 4 cathodes during lithium ion insertion\\/extraction  

Microsoft Academic Search

Equilibrium potential hysteresis of electrode materials refers to the phenomenon that discharge equilibrium potential is lower than charge equilibrium potential. It is induced by the strain accommodation energy of phase transformation. Taking LiFePO4 as an example, the equilibrium potential hysteresis and accommodation energy of two LiFePO4 with different particle sizes were characterized using galvanostatic intermittent titration technique (GITT), cyclic voltammetry

Yujie Zhu; Chunsheng Wang

2011-01-01

468

Magnetic hysteresis behavior and microstructure of severely cold-worked and aged Co-Fe-Nb alloy  

Microsoft Academic Search

The magnetic hysteresis behavior of severely cold-worked and aged 85Co-12Fe-3Nb alloy was studied in relation to the microstructure. Magnetic hardening of the alloy can be attributed to the pinning of the domain wall by quasispherical Co3Nb precipitates. Alloys cold worked to 97.8% reduction in area and aged at 700, 800, and 900 °C showed the hysteresis behavior characteristic of inhomogeneous

Yuichi Suzuki; Masato Sagawa; Masanori Okada; Zenzo Henmi

1979-01-01

469

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

470

Texture development and strain hysteresis in a NiTi shape-memory alloy during thermal cycling under load  

Microsoft Academic Search

Thermal cycling experiments were conducted on a NiTi shape-memory alloy at different constant applied stresses below the yield strength of the martensite. The mechanical strain response manifested as strain hysteresis loops, whose range was proportional to the applied stress. In situ neutron diffraction experiments show that the strain hysteresis occurs as a result of the establishment of a stress-dependent crystallographic

B. Ye; B. S. Majumdar; I. Dutta

2009-01-01

471

Effects of Control Hysteresis on the Space Shuttle Orbiter's Entry. M.S. Thesis - George Washington Univ.  

NASA Technical Reports Server (NTRS)

There are six degree-of-freedom simulations of the space shuttle orbiter entry with aerodynamic control hysteresis conducted on the NASA Langley Research Center interactive simulator known as the Automatic Reentry Flight Dynamics Simulator. These were performed to determine if the presence of aerodynamic control hysteresis would endanger the mission, either by making the vehicle unable to maintain proper attitude for a safe entry, or by increasing the amount of the reaction control system's fuel consumption beyond that carried.

Powell, R. W.

1975-01-01

472

Hysteresis of Magnetite, Hematite and Pyrrhotite Crystals at High and Low Temperatures  

NASA Astrophysics Data System (ADS)

Alternating gradient force magnetometers and sensitive vibrating-sample magnetometers operating above, at, and below room temperature have enabled rapid reliable measurements of hysteresis and remanence curves. The hysteresis parameters Ms, Mrs, Hc, plus the remanence coercivity Hcr, are routinely determined, at room temperature at least, and reported in the form of a Day plot as an indication of domain state and inferred grain size. Yet our knowledge of the hysteresis and remanence properties of individual crystals or sized crystal aggregates of magnetite, titanomagnetite, hematite, pyrrhotite and other important magnetic minerals has scarcely advanced beyond what was known at the end of the 1980's. Applications have indeed outstripped fundamental studies. This presentation will focus on new hysteresis measurements for well-sized magnetites of a variety of origins; magnetite inclusions in plagioclase, pyroxene, amphiboles and biotite; hematite; and pyrrhotite. Measurements were made at 20oC intervals from 25oC to the Curie point for all magnetites and hematites and at 10oC intervals for pyrrhotite. For one set of sized magnetites (0.6, 3, 6, 9, 14 and 110 micrometers), hysteresis and back-field remanence curves were also measured below room temperature (every 10 K from 10 K to 70 K, every 5 K from 80 K to 140 K, and every 10 K from 150 K to 300 K). These data give a wealth of information about the individual mineral crystals and trends linking crystals of common origin but different sizes. From Ms(T) we obtain precise Curie points and transition temperatures. Mrs(T)/Ms(T) tracks sometimes subtle changes in domain structure with changing temperature. Hc(T) gives an indication of the mechanism(s) of anisotropy, important for understanding TRM acquisition in crystals above single-domain size. Mrs(T) and Hc(T) often show substantial irreversible changes in the first heating- cooling cycle, particularly but not exclusively for synthetic crystals, stabilizing in subsequent cycles. Finally, Mrs(T)/Ms(T) vs. Hcr(T)/Hc(T) data trace curves on a Day plot showing unmistakable differences in domain structure between monoclinic and cubic magnetite, as well as more subtle changes away from the Verwey transition.

Dunlop, D. J.

2008-12-01

473

A suite of user-friendly global climate models: Hysteresis experiments  

NASA Astrophysics Data System (ADS)

A hierarchy of global spectral circulation models is introduced ranging from the shallow-water system via the primitive-equation dynamical core of the atmosphere to the Planet Simulator as a Global Climate Model (GCM) of Intermediate Complexity (MIC) which can be used to run climate and paleo-climate simulations for time scales up to ten thousand years or more in an acceptable real time. The priorities in development are set to speed, easy handling and portability with a modular structure suitable for problem-dependent configuration. Adaptions exist for the planetary atmospheres of Mars and of Saturn's moon Titan and are being extended. Common coupling interfaces enable the addition of ocean, ice, vegetation models and more. An interactive mode with a Model Starter and a Graphical User Interface (GUI) is available to select a configuration from the available model suite, to set its parameters and inspect atmospheric fields while changing the models' parameters on the fly. This is especially useful for teaching, debugging and tuning of parameterizations. An updated overview of the model suite's features is presented based on the Earth-like climate model Planet Simulator with mixed-layer ocean introducing static and memory hysteresis in terms of a parameter sweep of the solar constant and CO2 concentrations. The static hysteresis experiment demonstrates that the solar constant varying by 20% reveals warm and snowball Earth climate regimes depending on the history of the system. This hysteresis subjected to a thermodynamic analysis shows the following features: i) Both climate regimes are characterized by global mean surface temperature and entropy growing with increasing solar constant. ii) The climate system's efficiency decreases (increases) with increasing solar constant in present-day warm (snowball) climate conditions. iii) Climate transitions near bifurcation points are characterized by high efficiency associated with the system's large distance from the stable regime. Memory hysteresis evolves when changing the direct atmospheric radiative forcing which, associated with a well-mixed CO2 concentration, modifies the planetary thermodynamic state, and hence the surface temperature. The hysteresis effected by different CO2 change rates is analysed: i) The response is due to infrared cooling (for constant temperature lapse-rate) which, in turn, is related to the surface temperature through the Stefan-Boltzmann law in a ratio proportional to the new infrared opacity. Subsequent indirect effects, that are water-vapour-greenhouse and ice-albedo feedbacks, enhance the response. ii) Different rates of CO2 variation may lead to similar transient climates characterized by the same global mean surface temperature but different values of CO2 concentration. iii) Far from the bifurcation points, the model's climate depends on the history of the radiative forcing thus displaying a hysteresis cycle that is neither static nor dynamical, but is related to the memory response of the model determined by the mixed-layer depth of the ocean. Results are supported by a zero-dimensional energy balance model.

Fraedrich, K.

2012-05-01

474

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