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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

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

4

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

5

Plant thermal hysteresis proteins.  

PubMed

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

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

1992-05-22

6

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

7

Dynamical Hysteresis without Static Hysteresis: Scaling Laws and Asymptotic Expansions  

Microsoft Academic Search

Abstract. We study dynamical,hysteresis in a simple class of nonlinear ordinary dierential equations, namely rst-order equations subject to sinusoidal forcing. The assumed nonlinearities are such that the area of the hysteresis loop vanishes as the forcing frequency tends to zero; in other words, there is no static hysteresis. Using regular and singular perturbation techniques, we derive the rst term in

Guillermo H. Goldsztein; Fernando Broner; Steven H. Strogatz

1997-01-01

8

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

9

Modeling hysteresis in piezoceramic actuators  

Microsoft Academic Search

A major deficiency of piezoceramic actuators is that their open-loop control accuracy is seriously limited by hysteresis. This paper discusses the adaptation of the Preisach model to describe the nonlinear hysteresis behavior of these actuators. The adapted model is used to predict the response of a piezoceramic actuator to a sinusoidal input and a triangular input. The predictions are compared

Ping Ge; Musa Jouaneh

1995-01-01

10

Thermal hysteresis proteins.  

PubMed

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

Barrett, J

2001-02-01

11

Hysteresis losses in soft magnetic composite materials  

Microsoft Academic Search

Purpose – To analyze the Jiles and Atherton hysteresis model used for hysteresis losses estimation in soft magnetic composite (SMC) material. Design\\/methodology\\/approach – The Jiles and Atherton hysteresis model parameters are optimized with genetic algorithms (GAs) according to measured symmetric hysteresis loop of soft magnetic composite material. To overcome the uncertainty, finding the best-optimized parameters in a wide predefined searching

Bogomir Zidari?; Mykhaylo Zagirnyak; Konrad Lenasi; Damijan Miljavec

2006-01-01

12

HYSTERESIS ANALYSIS BASED ON INTEGRAL QUADRATIC CONSTRAINTS  

Microsoft Academic Search

It is shown how the framework of Integral Quadratic Constraints can be applied to analyze systems with hysteresis, in spite of the fact that hysteresis operators are unbounded and that not all system variable can be expected to approach zero.

A. Rantzer; A. Megretski

13

Kinetic Hysteresis in Collagen Folding  

PubMed Central

Abstract The triple helix of collagen shows a steep unfolding transition upon heating, whereas less steep and more gradual refolding is observed upon cooling. The shape of the hysteresis loop depends on the rate of temperature change as well as the peptide concentration. Experimental heating and cooling rates are usually much faster than rates of unfolding and refolding. In this work, collagen model peptides were used to study hysteresis quantitatively. Their unfolding and refolding profiles were recorded at different heating and cooling rates, and at different peptide concentrations. Data were fitted assuming kinetic mechanisms in which three chains combine to a helix with or without an intermediate that acts as a nucleus. A quantitative fit was achieved with the same kinetic model for the forward and backward reactions. Transitions of exogenously trimerized collagen models were also analyzed with a simplified kinetic mechanism. It follows that true equilibrium transitions can only be measured at high concentrations of polypeptide chains with slow scanning rates, for example, 0.1°C/h at 0.25 mM peptide concentration of (Gly-Pro-Pro)10. (Gly-Pro-4(R)Hyp)10 folds ?2000 times faster than (Gly-Pro-Pro)10. This was explained by a more stable nucleus, whereas the rate of propagation was almost equal. The analysis presented here can be used to derive kinetic and thermodynamic data for collagenous and other systems with kinetically controlled hysteresis. PMID:20550913

Mizuno, Kazunori; Boudko, Sergei P.; Engel, Jürgen; Bächinger, Hans Peter

2010-01-01

14

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

15

Improved charge amplifier using hybrid hysteresis compensation  

NASA Astrophysics Data System (ADS)

We present a novel charge amplifier, with a robust feedback circuit and a method for compensating piezoelectric actuator's hysteresis at low frequencies. The amplifier uses a modified feedback circuit which improves robustness to the addition of series load impedance such as in cabling. We also describe a hybrid hysteresis compensation method for enabling the charge amplifier to reduce hysteresis at low frequencies. Experimental results demonstrate the utility of the new amplifier design.

Amin-Shahidi, Darya; Trumper, David L.

2013-08-01

16

Classical and hyperbolic approximation of hysteresis loops  

NASA Astrophysics Data System (ADS)

Analytical approximation of symmetrical and unsymmetrical hysteresis loops is based on the general description of magnetization consisting of the slow reversible process and more violent irreversible process. The coercivity term in the irreversible component generates symmetrical hysteresis loops, which are used for the approximation of first-order reversal curves and their distribution. Model has been applied to materials with typical S-shaped and rectangular hysteresis loops.

W?odarski, Zdzis?aw

2007-02-01

17

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

18

Corneal hysteresis and its relevance to glaucoma  

PubMed Central

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

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

2015-01-01

19

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

20

Analysis of hunting in Synchronous Hysteresis Motor  

E-print Network

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

Truong, Cang Kim, 1979-

2004-01-01

21

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

22

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

23

SPECIAL FEATURE Social hysteresis and ecological hysteresis Maja Schlu ter Heather Leslie Simon Levin  

E-print Network

complex and often conflicting demands for water among different uses and users in a river basinSPECIAL FEATURE Social hysteresis and ecological hysteresis Maja Schlu¨ ter � Heather Leslie � Simon Levin Managing water-use trade-offs in a semi-arid river delta to sustain multiple ecosystem

Leslie, Heather

24

Magnetic hysteresis in integrated low T sub c SQUID gradiometers  

SciTech Connect

We have measured the magnetic hysteresis of thin-film superconducting gradiometers. The fractional hysteresis error {ital h} was found to be about 10{sup {minus}9}--10{sup {minus}11} in several devices.

Koch, R.H.; Ketchen, M.B.; Gallagher, W.J.; Sandstrom, R.L.; Kleinsasser, A.W. (IBM Research Division, Yorktown Heights, New York 10598 (USA)); Gambrel, D.R.; Field, T.H. (IBM Federal Sector Division, Manassas, Virginia 22110 (USA)); Matz, H. (University Karlsruhe, D-7500 Karlsruhe 21, (Germany))

1991-04-22

25

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

26

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

27

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

28

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

29

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

30

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

31

Modeling rate-dependent hysteresis in piezoelectric actuators  

Microsoft Academic Search

Hysteresis of a piezoelectric actuator is rate dependent. Most hysteresis models are based on elementary rate independent operators and are not suitable for modeling actuator behavior across a wide frequency band. This work proposes a rate dependent modified Prandtl-Ishlinskii (PI) operator to account for the hysteresis of a piezoelectric actuator at varying frequency. We have shown experimentally that the relationship

Francisco Alija Garmón; Pradeep K. Khosla; Cameron N. Riviere

2003-01-01

32

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

33

Rheological Hysteresis in Soft Glassy Materials  

NASA Astrophysics Data System (ADS)

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

Divoux, Thibaut; Grenard, Vincent; Manneville, Sébastien

2013-01-01

34

Adsorption kinetics in the solution of a thermal hysteresis protein  

NASA Astrophysics Data System (ADS)

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

Li, Qianzhong; Luo, Liaofu

2000-04-01

35

Hysteresis prediction inside magnetic shields and application  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

36

Hysteresis prediction inside magnetic shields and application.  

PubMed

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

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

2014-07-01

37

Friction and Adhesion Hysteresis between Surfactant Monolayers in Water  

E-print Network

Friction and Adhesion Hysteresis between Surfactant Monolayers in Water Wuge H. Briscoe Physical friction between two surfaces in adhesive contact with the loading­unloading adhesion hysteresis between them. We then examine in light of this model the observed low friction between two mica surfaces coated

Klein, Jacob

38

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

39

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

40

Magnetic hysteresis under compressive stress at high applied field  

Microsoft Academic Search

n Abstract-The magnetic properties of material are sensitive to applied stress. The aim of this paper is to designed and fabricated a hysteresis imaging apparatus for nondestructive evaluation of stress concentration in ferromagnetic material. It has been applied successfully to measure the hysteresis loops of Q235 steel under various fixed compressive stress. The remanence Br derived from the loops is

Dongyan Huang; Bing Han; Zonggang Wang; Tao Zhang

2011-01-01

41

Scaling Laws for Dynamical Hysteresis in a Multidimensional Laser System  

Microsoft Academic Search

We examine scaling laws for dynamical hysteresis in an optically bistable semiconductor laser. An analytic derivation of these laws from multidimensional laser equations is outlined and they are expected to be universal for systems that exhibit a cusp catastrophe. The scaling laws for the hysteresis loop area or width are numerically verified and experimentally measured for operation of the bistable

Angela Hohl; Rajarshi Roy; Guillermo Goldsztein; Fernando Broner; Steven H. Strogatz

1995-01-01

42

The origin of hysteresis in the flag instability  

Microsoft Academic Search

The flapping flag instability occurs when a flexible cantilevered plate is immersed in a uniform airflow. To this day, the nonlinear aspects of this aeroelastic instability are largely unknown. In particular, experiments in the literature all report a large hysteresis loop, while the bifurcation in numerical simulations is either supercritical or subcritical with a small hysteresis loop. In this paper,

Christophe Eloy; Nicolas Kofman; Lionel Schouveiler

2011-01-01

43

Generalized preisach model for hysteresis nonlinearity of piezoceramic actuators  

Microsoft Academic Search

This paper presents a new approach for modeling the hysteresis nonlinearity of a piezoceramic actuator using a modified generalized Preisach model, and the use of this model in a linearizing control scheme. The developed generalized Preisach model relaxes the congruency requirement on the hysteresis loops of a piezoceramic actuator, which must be satisfied when using the classical Preisach model. The

Ping Ge; Musa Jouaneh

1997-01-01

44

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith  

E-print Network

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith Center for Research in Scientific.hom@lmco.com Abstract This paper addresses the modeling of hysteresis in ferroelectric materials through consideration comparison with experimental data from a PMN­PT­BT actuator operating at a temperature within

45

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith  

E-print Network

A Domain Wall Theory for Ferroelectric Hysteresis Ralph C. Smith Center for Research in Scienti c.hom@lmco.com Abstract This paper addresses the modeling of hysteresis in ferroelectric materials through consideration comparison with experimental data from a PMN-PT-BT actuator operating at a temperature within

46

Preisach Polarization-Electric Field Hysteresis Model with Iteration Method  

NASA Astrophysics Data System (ADS)

In this study, we introduce an iteration method for obtaining the distribution function of the Preisach polarization-electric field (P-E) hysteresis model for piezoelectric actuators. In a previously proposed method, numerous experimental hysteresis curves were indispensable for this function. On the other hand, by using the iteration method, only one major-loop experiment is sufficient. From this distribution function, any minor-loop hysteresis can be simulated by the Preisach distribution function F(i,j) with high resolution. First, we measured a hysteresis property of the polarization P versus input voltage V of the ferroelectric material. On the basis of this one hysteresis curve, the distribution function was obtained using the iteration method. Using this function, we could simulate the minor loops, and the simulation results showed good agreement with experimental data.

Ikeda, Hideyuki; Kadota, Yoichi; Morita, Takeshi

2012-09-01

47

Neural networks dynamic hysteresis model for piezoceramic actuator based on hysteresis operator of first-order differential equation  

Microsoft Academic Search

A new neural networks dynamic hysteresis model for piezoceramic actuator is proposed by combining the Preisach model with diagonal recurrent neural networks. The Preisach model is based on elementary rate-independent operators and is not suitable for modeling piezoceramic actuator across a wide frequency band because of the rate-dependent hysteresis characteristic of the piezoceramic actuator. The structure of the developed model

Xuanju Dang; Yonghong Tan

2005-01-01

48

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

49

Hysteresis in forced oscillations of pendant drops  

SciTech Connect

A hysteresis phenomenon has been revealed through experiments conducted with large-amplitude forced oscillations of pendant drops in air. Under strong excitation, the frequency response of a drop forced at constant amplitude exhibits jump behavior; a larger peak response amplitude {epsilon}{sub {down_arrow}} appears at a lower frequency {omega}{sub {down_arrow}} during a downward ({down_arrow}) variation of forcing frequency than during an upward ({up_arrow}) variation, viz. {epsilon}{sub {down_arrow}}{gt}{epsilon}{sub {up_arrow}} and {omega}{sub {down_arrow}}{lt}{omega}{sub {up_arrow}}. Similar results are obtained when forcing amplitude is varied at constant frequency. This behavior is characteristic of a system with a soft nonlinearity. These findings indicate that oscillating pendant drops constitute a convenient system for studying nonlinear dynamics.

DePaoli, D.W.; Feng, J.Q.; Basaran, O.A.; Scott, T.C. [Chemical Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6224 (United States)] [Chemical Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6224 (United States)

1995-06-01

50

Contact angle hysteresis on superhydrophobic stripes  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

51

Contact angle hysteresis on superhydrophobic stripes.  

PubMed

We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ?S. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ?S. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ?S(2)ln?S. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ?S, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ?S ? 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ?S(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ?S ? 0.2. PMID:25149809

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

2014-08-21

52

Understanding the Hysteresis Loop Conundrum in Pharmacokinetic / Pharmacodynamic Relationships  

PubMed Central

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

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

2015-01-01

53

Constricted hysteresis loops in Fe and Ni single crystals  

NASA Astrophysics Data System (ADS)

Magnetic hysteresis loops reflect the variety of magnetic domain structures and have been considered to have normal rectangular or leaf-like shapes in standard ferromagnets such as Fe and Ni metals. We report on observations of constricted hysteresis loops in Fe and Ni single crystals with very low defect densities. The constricted loops were observed below T=150 K and in a medium temperature range from 150 to 430 K in Fe and Ni single crystals, respectively. These constricted loops disappear by weak plastic deformation for both single crystals. The origin of constricted hysteresis loops was explained by eddy current effects under less domain wall pinning due to dislocations.

Takahashi, Seiki; Kobayashi, Satoru; Shishido, Toetsu

2010-11-01

54

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

55

A constitutive model for the frequency dependence of magnetic hysteresis  

NASA Astrophysics Data System (ADS)

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

Ho, Kwangsoo

2014-10-01

56

Adaptive feed-forward hysteresis compensation for piezoelectric actuators  

NASA Astrophysics Data System (ADS)

Piezoelectric actuators are often employed for high-resolution positioning tasks. Hysteresis and creep nonlinearities inherent in such actuators deteriorate positioning accuracy. An online adaptive nonlinear hysteresis compensation scheme for the case of symmetric hysteretic responses and certain periodic reference trajectories is presented. The method has low complexity and is well suited for real-time implementation. Experimental results are presented in order to verify the method, and it is seen that the error due to hysteresis is reduced by more than 90% compared to when assuming a linear response.

Eielsen, Arnfinn Aas; Gravdahl, Jan Tommy; Pettersen, Kristin Y.

2012-08-01

57

A new approach to the characterization of reverse osmosis membrane by dynamic hysteresis  

Microsoft Academic Search

Physical aspects of dynamic hysteresis for characterizing reverse osmosis (RO) membranes have been investigated. Dynamic hysteresis was used as a parameter of showing physical surface characteristics of RO membranes. Automated microbalance was utilized to determine dynamic hysteresis based on the Wilhelmy plate method. Dynamic hysteresis determined with non-polar liquid was related to physical surface characteristics including surface roughness and heterogeneity

Eunsu Lee; Sangyoup Lee; Seungkwan Hong

2010-01-01

58

The hysteresis motor-advances whick permit economical fractional horsepower ratings  

Microsoft Academic Search

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

Herbert C. Roters

1947-01-01

59

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

60

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

61

A high-speed hysteresis drive with pulsed overdrive  

NASA Astrophysics Data System (ADS)

The pulsed overdrive (Delektorskii and Tarasov, 1974) is a special magnetization mode of a hysteresis motor. Consideration is given here to a drive with pulsed overdrive in which field extinction is used to improve the energy characteristics of the motor.

Pozdnykhov, S. F.; Tarasov, V. N.

62

Titration and hysteresis in epigenetic chromatin silencing  

NASA Astrophysics Data System (ADS)

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.

Dayarian, Adel; Sengupta, Anirvan M.

2013-06-01

63

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

64

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

65

Stabilization of supercooled fluids by thermal hysteresis proteins.  

PubMed

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

Wilson, P W; Leader, J P

1995-05-01

66

Asymmetric Hysteresis Loops and the Pyroelectric Effect in Triglycine Sulfate  

Microsoft Academic Search

Dynamic pyroelectric techniques have been used to study single crystal triglycine sulfate hysteresis loops at room temperature. An apparent polarization bias is observed and is similar to that reported earlier for BaTiO3. The apparent polarization bias can be shifted with the application of a dc electric field. When precautions are taken to eliminate electrode-edge effects, the pyroelectric hysteresis loops are

Albert Savage; Robert C. Miller

1959-01-01

67

A MHO-based magnetic hysteresis model for amorphous materials  

NASA Astrophysics Data System (ADS)

A magnetic hysteretic operator (MHO) is proposed in this paper. Based on the constructed MHO, the input space of neural networks is expanded from one-dimension to two-dimension using the expanded space method so that the one-to-multiple mapping of magnetic hysteresis is transformed into one-to-one mapping. Based on the expanded input space, a neural network is employed to identify magnetic hysteresis. The result of an experimental example suggests the proposed approach is effective.

Ma, Lianwei; Shen, Yu; Li, Jinrong; Zhao, Xinlong

2014-12-01

68

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

69

A new model of hysteresis in piezoelectric actuators  

Microsoft Academic Search

Piezoelectric actuators (PEAs) are widely used in micromanipulations for their high-accuracy positioning, fast response, and high mechanical stiffness. However, dynamic nonlinearity introduced by hysteresis phenomena causes system instability and positioning errors. In this paper, a new simple physical model is proposed to characterize the symmetric and asymmetric rate-dependent hysteresis. A nonlinear spring (or capacitor) element is incorporated into a second-order

Issam M. Bahadur; James K. Mills

2011-01-01

70

Modeling and control of hysteresis in magnetostrictive actuators  

Microsoft Academic Search

Abstract A novel dynamic model is proposed for the hysteresis in magnetostrictive actuators by coupling a Preisach operator to an ordinary di0erential equation, and a parameter identi2cation method is described. An e3cient inversion algorithm for a class of Preisach operators with piecewise uniform density functions is then introduced, based upon which an inverse control scheme for the dynamic hysteresis model

Xiaobo Tan; John S. Baras

2004-01-01

71

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

72

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

73

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

74

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

75

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.

76

Saturation overshoot and hysteresis for twophase flow in porous media  

NASA Astrophysics Data System (ADS)

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

Hilfer, R.; Steinle, R.

2014-10-01

77

Hysteresis modeling in ballistic carbon nanotube field-effect transistors  

PubMed Central

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

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

2014-01-01

78

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

79

Persistent hysteresis in graphene-mica van der Waals heterostructures  

NASA Astrophysics Data System (ADS)

We report the study of electronic transport in graphene-mica van der Waals heterostructures. We have designed various graphene field-effect devices in which mica is utilized as a substrate and/or gate dielectric. When mica is used as a gate dielectric we observe a very strong positive gate voltage hysteresis of the resistance, which persists in samples that were prepared in a controlled atmosphere down to even millikelvin temperatures. In a double-gated mica-graphene-hBN van der Waals heterostructure, we found that while a strong hysteresis occurred when mica was used as a substrate/gate dielectric, the same graphene sheet on mica substrate no longer showed hysteresis when the charge carrier density was tuned through a second gate with the hBN dielectric. While this hysteretic behavior could be useful for memory devices, our findings confirm that the environment during sample preparation has to be controlled strictly.

Mohrmann, Jens; Watanabe, Kenji; Taniguchi, Takashi; Danneau, Romain

2015-01-01

80

Hysteresis and interfacial energies in smooth-walled microfluidic channels  

NASA Astrophysics Data System (ADS)

Hysteresis in the capillary pressure-saturation relationship (Pc-Sw) for a porous medium has contributions from the complex geometry of the pore network as well as the physical chemistry of the grain surfaces. To isolate the role of wettability on hysteresis, we fabricated microfluidic cells that contain a single wedge-shaped channel that simulates a single pore throat. Using confocal microscopy of the three-dimensional interfaces under imbibition and drainage, we demonstrate an accurate balance between mechanical work and surface free energy that was evaluated using measured advancing and receding contact angles. The closed-loop mechanical work per surface water molecule is 95 kJ/mol, which is consistent with physisorption. Therefore, the hysteresis in the Pc-Sw relationship for a single pore throat is defined by advancing and receding contact angles that are controlled by dissipative surface adsorption chemistry.

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

2011-01-01

81

Contact Hysteresis and Friction of Alkanethiol SAMs on Au  

SciTech Connect

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

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

1998-10-14

82

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

83

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

84

Dynamic hysteresis in cyclic deformation of crystalline solids.  

PubMed

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. PMID:23102332

Laurson, Lasse; Alava, Mikko J

2012-10-12

85

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

86

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

87

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

88

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

E-print Network

. Introduction Ferromagnetic and ferroelectric materials are increasingly considered for use as actuators, charge or current controlled amplifiers can minimize observed hysteresis in ferroelectric actuators [15Quantification of Hysteresis and Nonlinear Effects on the Frequency Response of Ferroelectric

89

A Homogenized Energy Model for Hysteresis in Ferroelectric Materials: General Density Formulation  

E-print Network

of ferroelectric compounds as actuators and sensors in high performance control applications has burgeonedA Homogenized Energy Model for Hysteresis in Ferroelectric Materials: General Density Formulation hysteresis and constitutive nonlinearities in ferroelectric compounds based on energy analysis at mesoscopic

90

A Preisach Model for Quantifying Hysteresis in an Atomic Force Microscope  

E-print Network

A Preisach Model for Quantifying Hysteresis in an Atomic Force Microscope Ralph C. Smith # , Murti Atomic force microscopes employ stacked or cylindrical piezoceramic actuators to achieve sub. Keywords: Atomic force microscope, hysteresis, constitutive nonlinearities, Preisach model 1. Introduction

91

A Preisach Model for Quantifying Hysteresis in an Atomic Force Microscope  

E-print Network

A Preisach Model for Quantifying Hysteresis in an Atomic Force Microscope Ralph C. Smith , Murti Atomic force microscopes employ stacked or cylindrical piezoceramic actuators to achieve sub in various control designs. Keywords: Atomic force microscope, hysteresis, constitutive nonlinearities

92

Rainflow Counting and Energy Dissipation for Hysteresis Models in Elastoplasticity  

E-print Network

Republic Abstract The rainflow counting method is widely used in the context of fatigue analy- sis. The rainflow counting method due to Endo is widely used to decompose an arbitrary sequence of (scalar) loadsRainflow Counting and Energy Dissipation for Hysteresis Models in Elastoplasticity Martin Brokate

Krejcí, Pavel

93

The influence of magnetic hysteresis on magnetorheological fluid clutch operation  

Microsoft Academic Search

Purpose – The purpose of this paper is to elaborate upon the mathematical model of coupled electromagnetic, fluid dynamic and motion phenomena that will allow for investigation of the magnetic hysteresis influence on the axial symmetry magnetorheological fluid (MRF) clutch operation. Design\\/methodology\\/approach – To solve the partial differential equations describing magnetic vector and fluid velocity potential distributions in axial symmetry

Cezary J?dryczka; Piotr Sujka; Wojciech Szel?g

2009-01-01

94

Subharmonic ferroresonance in an LCR circuit with hysteresis  

E-print Network

, requires the use of nonlinear dynamics methods. A sinusoidally­driven series LCR circuit is one the Preisach model to simulate numerically a series LCR circuit (the same method can of course be appliedSubharmonic ferroresonance in an LCR circuit with hysteresis H. LAMBA # M.GRINFELD # S.McKEE # R

Lamba, Harbir

95

The back transition and hysteresis effects in DIII-D  

SciTech Connect

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

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

1997-09-01

96

The mechanism by which fish antifreeze proteins cause thermal hysteresis  

Microsoft Academic Search

Antifreeze proteins are characterised by their ability to prevent ice from growing upon cooling below the bulk melting point. This displacement of the freezing temperature of ice is limited and at a sufficiently low temperature a rapid ice growth takes place. The separation of the melting and freezing temperature is usually referred to as thermal hysteresis, and the temperature of

Erlend Kristiansen; Karl Erik Zachariassen

2005-01-01

97

A simple model of hysteresis behavior using spreadsheet analysis  

NASA Astrophysics Data System (ADS)

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

Ehrmann, A.; Blachowicz, T.

2015-01-01

98

Idealized Hysteresis Modeling of Electrorheological and Magnetorheological Dampers  

Microsoft Academic Search

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

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

1998-01-01

99

Modeling of a Magnetorheological Actuator Including Magnetic Hysteresis  

Microsoft Academic Search

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

Jinung An; Dong-Soo Kwon

2003-01-01

100

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

101

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

102

A Domain Wall Model for Hysteresis in Piezoelectric Materials  

E-print Network

to attain the full potential of the materials as sensors and actuators in high performance applications. The model employed here is based on theory developed in [18, 19] for hysteresis in general ferroelectric design. i #12; 1 Introduction Piezoelectric materials provide the capability for designing actuators

103

Electroelastic equations describing slow hysteresis in polarized ferroelectric ceramic plates  

Microsoft Academic Search

Rotationally invariant electroelastic equations are extended to account for slow hysteretic effects in polarized ferroelectric ceramic plates by employing an internal variable in a thermodynamic state function. All material irreversibility is taken to be a consequence of the ferroelectric polarization-electric-field irreversibility. Since we are concerned with the slowest possible hysteresis, we ignore the evolution equation and take the known irreversible

L. Huang; H. F. Tiersten

1998-01-01

104

A Free Energy Model for Hysteresis in Ferroelectric Materials  

E-print Network

A Free Energy Model for Hysteresis in Ferroelectric Materials Ralph C. Smith Stefan Seelecke The capability of piezoelectric materials to both actuate and sense derives from the noncentrosym­ metric nature. This generates strains in the material and provides it with actuator capabilities. Alternatively, applied

105

A Free Energy Model for Hysteresis in Ferroelectric Materials  

E-print Network

A Free Energy Model for Hysteresis in Ferroelectric Materials Ralph C. Smith Stefan Seelecke The capability of piezoelectric materials to both actuate and sense derives from the noncentrosym- metric nature. This generates strains in the material and provides it with actuator capabilities. Alternatively, applied

106

A Stress-Dependent Hysteresis Model for Ferroelectric Materials  

E-print Network

exploiting ferroelectric compounds -- e.g., PZT, PLZT and PMN -- offer unique actuator and sensorA Stress-Dependent Hysteresis Model for Ferroelectric Materials Brian L. Ball 1 , Ralph C. Smith 2 models which characterize the fer- roelastic switching mechanisms inherent to ferroelectric materials

107

A TemperatureDependent Hysteresis Model for Relaxor Ferroelectrics  

E-print Network

. Introduction Actuators constructed from the relaxor ferroelectric material Pb(Mg 1=3 , Nb 2=3 )O 3 (PMNA Temperature­Dependent Hysteresis Model for Relaxor Ferroelectrics Ralph C. Smith 1 and Craig L addresses the development of a temperature­dependent constitutive model for relaxor ferroelectrics which

108

Ferroelectric non-hysteresis actuator for microwave tuneable devices  

Microsoft Academic Search

Low loss and highly tuneable microwave filters controlled by piezoelectric actuator are discussed. Dielectric or metallic parts of device should have the piezo-dirigible air gap between them. The most important for these devices is to use non-hysteresis relaxor ferroelectric ceramics with large electrostriction. Electromechanic way of control has restriction in the speed of operation, and this problem is estimated by

Y. M. Poplavko; S. A. Voronov

2010-01-01

109

Parameter Estimation Techniques for a Class of Nonlinear Hysteresis Models  

E-print Network

materials employed in a wide range of actuators and sensors. These models are formulated as integral through comparison with experimental data. i #12;1 Introduction Hysteresis and constitutive nonlinearities frequency, temperature, and stress dependencies which makes it applicable for a wide range of transducer

110

PID Control of Second-Order Systems with Hysteresis  

E-print Network

PID Control of Second-Order Systems with Hysteresis Bayu Jayawardhana, Hartmut Logemann & Eugene P 2007 Abstract. The efficacy of proportional, integral and derivative (PID) control for set point on the PID gains, explicitly formulated in terms of the system data, are determined under which asymptotic

Ryan, E.P.

111

Sensor Saturation for Hysteresis Reduction in GMR Magnetometers  

E-print Network

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

Krchnavek, Robert R.

112

A Differential Model of Adsorption Hysteresis with Applications to Chromatography  

E-print Network

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

Peszynska, Malgorzata

113

Open-loop position tracking control of a piezoceramic flexible beam using a dynamic hysteresis compensator  

NASA Astrophysics Data System (ADS)

This paper proposes a novel hysteresis compensator to enhance control accuracy in open-loop position tracking control of a piezoceramic flexible beam. The proposed hysteresis compensator consists of two components: a rate-independent hysteresis compensator and a nonlinear filter. The compensator is formulated based on the inverse Preisach model, while the weight coefficients of the filter are identified adaptively using a recursive least square (RLS) algorithm. In this work, two dynamic hysteresis compensators (or rate-independent hysteresis compensators) are developed by adopting two different nonlinear filters: Volterra and bilinear filters. In order to demonstrate the improved control accuracy of the proposed dynamic compensators, a flexible beam associated with the piezoceramic actuator is modeled using the finite element method (FEM) and Euler-Bernoulli beam theory. The beam model is then integrated with the proposed hysteresis model to achieve accurate position tracking control at the tip of the beam. An experimental investigation on the tip position tracking control is undertaken by realizing three different hysteresis compensators: a rate-independent hysteresis compensator, a rate-dependent hysteresis compensator with a Volterra nonlinear filter and a rate-independent hysteresis compensator with a bilinear nonlinear filter. It is shown that the proposed dynamic hysteresis compensators can provide much better tracking control accuracy than conventional rate-independent hysteresis compensators.

Nguyen, Phuong-Bac; Choi, Seung-Bok

2010-12-01

114

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

Microsoft Academic Search

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

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

2008-01-01

115

Unit Root in the Wage-Price Spiral Is Not Hysteresis in Unemployment  

Microsoft Academic Search

Hysteresis is one of the main concepts used in Layard, Nickell and Jackman's book, Unemployment: Macroeconomic Performance and the Labour Market. Attempts to clarify the concept of hysteresis, from its formal representation to its empirical applications. Emphasizes the idea that hysteresis refers back to a given set of formal properties, independently of the phenomenologies within which it is liable to

Bruno Amable; Jérôme Henry; Frédéric Lordon; Richard Topol

1993-01-01

116

Online Computation of Hysteresis Boundary for Constant Switching Frequency Current-Error Space-Vector-Based Hysteresis Controller for VSI-Fed IM Drives  

Microsoft Academic Search

This paper proposes a current-error space-vector-based hysteresis controller with online computation of boundary for two-level inverter-fed induction motor (IM) drives. The proposed hysteresis controller has got all advantages of conventional current-error space-vector-based hysteresis controllers like quick transient response, simplicity, adjacent voltage vector switching, etc. Major advantage of the proposed controller-based voltage-source-inverters-fed drive is that phase voltage frequency spectrum produced is

Rijil Ramchand; K. Gopakumar; Chintan Patel; K. Sivakumar; Anandarup Das; Haitham Abu-Rub

2012-01-01

117

Attachment/detachment hysteresis of fiber-based magnetic grabbers.  

PubMed

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

Gu, Yu; Kornev, Konstantin G

2014-04-28

118

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

119

Hysteresis Behaviors of Poly (Naphthalene Quinone) Radical Electrorheological Fluid  

NASA Astrophysics Data System (ADS)

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

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

120

A new ferromagnetic hysteresis model for soft magnetic composite materials  

NASA Astrophysics Data System (ADS)

A new ferromagnetic hysteresis model for soft magnetic composite materials based on their specific properties is presented. The model relies on definition of new anhysteretic magnetization based on the Cauchy-Lorentz distribution describing the maximum energy state of magnetic moments in material. Specific properties of soft magnetic composite materials (SMC) such as the presence of the bonding material, different sizes and shapes of the Fe particles, level of homogeneity of the Fe particles at the end of the SMC product treatment, and achieved overall material density during compression, are incorporated in both the anhysteretic differential magnetization susceptibility and the irreversible differential magnetization susceptibility. Together they form the total differential magnetization susceptibility that defines the new ferromagnetic hysteresis model. Genetic algorithms are used to determine the optimal values of the proposed model parameters. The simulated results show good agreement with the measured results.

Zidari?, Bogomir; Miljavec, Damijan

2011-01-01

121

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

PubMed

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

Hoshino, T; Kiriaki, M; Nakajima, T

2003-01-01

122

A calorimetric study of thermal hysteresis effects in ganglioside micelles  

Microsoft Academic Search

Light, X-ray and neutron scattering measurements clearly showed strong temperature-related variations in micellar mean aggregation\\u000a number, accompanied by dramatic thermal hysteresis effects, for a variety of micelle-forming gangliosides. Gangliosides, sialic-acid-containing\\u000a glycosphingolipids, are amphiphilic molecules of biological origin with a ceramide (a double-tailed hydrophobic part, like\\u000a phospholipids) and an oligosaccharide chain as the headgroup. When temperature is varied in the range

L. Cantù; M. Corti; E. Del Favero; E. Muller; A. Raudino; S. Sonnino

123

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

124

Hysteresis in acoustical media with relaxational nonlinearity and viscosity  

NASA Astrophysics Data System (ADS)

Loading and unloading waves in nonlinear relaxational and dissipative medium of type compacted ground are studied. Suggested by J. Stokes method and new asymptotic small-distance approach are used for construction of solution. We obtain explicit approximation solutions for different values of relaxation and viscous parameters. It is described influence of type of medium on form of hysteresis curves and on value of residual deformation.

Molotkov, I. A.

2008-06-01

125

Negative resistance and anomalous hysteresis in a collective molecular motor  

PubMed

A spatially extended model for a collective molecular motor is presented. The system is driven far from equilibrium by a quenched additive noise. As a result, it exhibits anomalous transport properties, namely, negative resistance and a clockwise hysteresis cycle. The phase diagram and the region of negative resistance are calculated using a Weiss mean field theory. Intuitive explanations of the anomalous transport properties as well as details of its energetics are given. PMID:11088302

Buceta; Parrondo; Van Den Broeck C; de La Rubia FJ

2000-06-01

126

The field-space perspective on hysteresis in uniaxial ferromagnets  

Microsoft Academic Search

A procedure for the analysis of hysteresis in the H space of a uniaxial ferromagnet with higher-order anisotropy is put forward. The formulation is valid to any order n in the anisotropy expansion. The critical boundaries separating stable from metastable states are cast in a formally decoupled parametric way as Hx=Hx(Mx), Hz=Hz(Mz). The analytic expressions provide the basis for the

Y. T. Millev; J. R. Cullen; H. P. Oepen

1998-01-01

127

The Field-Space Perspective on Hysteresis in Uniaxial Ferromagnets  

Microsoft Academic Search

A procedure for the analysis of hysteresis in the H space of a uniaxial ferromagnet with higher-order anisotropy is put forward. The formulation is valid to any order n in the anisotropy expansion. The critical boundaries separating stable from metastable states are cast in a formally decoupled parametric way as Hx5Hx( Mx), Hz5Hz(Mz). The analytic expressions provide the basis for

Y. T. Miller; J. R. Cullen; H. P. Oepen; J. Kirschner

1998-01-01

128

The field-space perspective on hysteresis in uniaxial ferromagnets  

Microsoft Academic Search

A procedure for the analysis of hysteresis in the H space of a uniaxial ferromagnet with higher-order anisotropy is put forward. The formulation is valid to any order n in the anisotropy expansion. The critical boundaries separating stable from metastable states are cast in a formally decoupled parametric way as Hx=Hx(Mx),Hz=Hz(Mz). The analytic expressions provide the basis for the construction

Y. T. Millev; J. R. Cullen; H. P. Oepen

1998-01-01

129

Barkhausen discontinuities and hysteresis of ferromagnetics: New stochastic approach  

SciTech Connect

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

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

2014-02-18

130

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

131

Simple models for dynamic hysteresis loops calculation: Application to hyperthermia optimization  

E-print Network

To optimize the heating properties of magnetic nanoparticles (MNPs) in magnetic hyperthermia applications, it is necessary to calculate the area of their hysteresis loops in an alternating magnetic field. The three types of theories suitable to describe the hysteresis loops of MNPs are presented and compared to numerical simulations: equilibrium functions, Stoner-Wohlfarth model based theories (SWMBTs) and linear response theory (LRT). Suitable formulas to calculate the hysteresis area of major cycles are deduced from SWMBTs and from numerical simulations; the domain of validity of the analytical formula is explicitly studied. In the case of minor cycles, the hysteresis area calculations are based on the LRT. A perfect agreement between LRT and numerical simulations of hysteresis loops is obtained. The domain of validity of the LRT is explicitly studied. Formulas to calculate the hysteresis area at low field valid for any anisotropy of the MNP are proposed. Numerical simulations of the magnetic field dependen...

Carrey, J; Respaud, M

2010-01-01

132

Hysteresis Phenomena for the Series Circuit of Two Identical Negative Differential Resistance Devices  

Microsoft Academic Search

The hysteresis phenomena and current-voltage (I-V) characteristics of a series combination of two identical negative differential resistance (NDR) devices are analyzed. In this study, two different cases are discussed. The analysis shows that hysteresis phenomena in the combined I-V characteristics depend upon the electrical parameters of the series-connected NDR devices. The relationships between the hysteresis voltage and electrical parameters are

Kwang-Jow Gan

2001-01-01

133

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

134

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

135

Quenching of giant hysteresis effects in La1-zYzHx switchable mirrors  

Microsoft Academic Search

The giant intrinsic hysteresis as a function of hydrogen concentration x in the optical and electrical properties of the archetypal switchable mirror YHx is eliminated by alloying Y with the chemically similar La. The La1-zYzHx films with z?0.67 are essentially hysteresis-free. The origin of the large hysteresis of alloys with z?0.86 is the large uniaxial lattice expansion that accompanies their

Gogh van A. T. M; D. G. Nagengast; E. S. Kooij; N. J. Koeman; R. P. Griessen

2000-01-01

136

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

Microsoft Academic Search

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

Lina Hao; Zhi Li

2010-01-01

137

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

SciTech Connect

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

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

1993-09-07

138

Fabrication of surfaces with extremely high contact angle hysteresis from polyelectrolyte multilayer.  

PubMed

High contact angle hysteresis on polyelectrolyte multilayers (PEMs) ion-paired with hydrophobic perfluorooctanoate anions is reported. Both the bilayer number of PEMs and the ionic strength of deposition solutions have significant influence on contact angle hysteresis: higher ionic strength and greater bilayer number cause increased contact angle hysteresis values. The hysteresis values of ~100° were observed on smooth PEMs and pinning of the receding contact line on hydrophilic defects is implicated as the cause of hysteresis. Surface roughness can be used to further tune the contact angle hysteresis on the PEMs. A surface with extremely high contact angle hysteresis of 156° was fabricated when a PEM was deposited on a rough substrate coated with submicrometer scale silica spheres. It was demonstrated that this extremely high value of contact angle hysteresis resulted from the penetration of water into the rough asperities on the substrate. The same substrate hydrophobized by chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane exhibits high advancing contact angle and low hysteresis. PMID:22044032

Wang, Liming; Wei, Jingjing; Su, Zhaohui

2011-12-20

139

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

140

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

141

Computational micromagnetic study of particulate media hysteresis and recording  

NASA Astrophysics Data System (ADS)

A description of the micromagnetic theory, algorithms, computer software and computer hardware built and used to study particulate media particles, hysteresis and recording is first provided. This includes a derivation and analysis of the modified version of the Fast Multipole Method used in this dissertation. Results will then be presented on particulate media particle nucleation field dependence on particle shape, particle aspect ratio, ferromagnetic exchange energy and external magnetic field angle. Results on the discretization necessary to accurately model a particle will also be provided. The reversal mode of a particle will be simulated and analyzed. Simulated longitudinal and transverse hysteresis loops will be presented. Results will also be presented on particulate media coercivity and squareness dependence on volumetric packing fraction. Simulated recorded transition results will be given as well as total power spectra results for AC and DC erased particulate media. Numerical results will be compared to experimental data and analytical theories. Advice is provided on how to build a personal supercomputer like the one used in the numerical experiments of this dissertation.

Seberino, Christian

2000-11-01

142

Hysteresis and bristle stiffening effects of conventional brush seals  

NASA Astrophysics Data System (ADS)

Extensive testing of conventional brush seals has identified the phenomena of bristle 'hysteresis' and 'stiffening' with pressure as their two major drawbacks. Subsequent to any differential movement of the runner into the bristle pack due to its radial excursions or centrifugal/thermal growths, the displaced bristles do not recover against the frictional forces between them and the backing plate. As a result, a significant leakage increase is observed following any runner movement. Furthermore, the bristle pack exhibits a considerable stiffening effect with the application of pressure. This phenomenon adversely affects the life of the seal and the runner due to a highly increased mechanical contact pressure at the sliding interface. In comparison with these conventional design seals, the characteristics of an improved design, known as the 'low hysteresis' design, are presented here. This design shows a substantially lower degree of the detrimental effects mentioned above. This type of seal can maintain its reduced leakage characteristics throughout the running cycle with runner excursions and growths. The bristles also do not show any stiffening, up to a certain pressure threshold. Therefore, this seal also has a potential for a longer life than a brush seal of conventional design.

Basu, P.; Datta, A.; Johnson, R.; Loewenthal, R.; Short, J.

1993-06-01

143

Hysteresis-free operation of suspended carbon nanotube transistors.  

PubMed

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. PMID:20601944

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

2010-08-01

144

Irreversibility and hysteresis in redox molecular conduction junctions.  

PubMed

In this work we present and discuss theoretical models of redox molecular junctions that account for recent observations of nonlinear charge transport phenomena, such as hysteresis and hysteretic negative differential resistance (NDR). A defining feature in such models is the involvement of at least two conduction channels--a slow channel that determines transitions between charge states of the bridge and a fast channel that dominates its conduction. Using Marcus' theory of heterogeneous electron transfer (ET) at metal-molecule interfaces we identify and describe different regimes of nonlinear conduction through redox molecular bridges, where the transferring charge can be highly localized around the redox moiety. This localization and its stabilization by polarization of the surrounding medium and/or conformational changes can lead to decoupling of the current response dynamics from the time scale of the voltage sweep (that is, the current does not adiabatically follow the voltage), hence to the appearance of memory (thermodynamic irreversibility) in this response that is manifested by hysteresis in current-voltage cycles. In standard voltammetry such irreversibility leads to a relative shift of the current peaks along the forward and backward voltage sweeps. The common origin of these behaviors is pointed out, and expressions of the threshold voltage sweep rates are provided. In addition, the theory is extended (a) to analyze the different ways by which such phenomena are manifested in single sweep cycles and in ensemble averages of such cycles and (b) to examine quantum effects in the fast transport channel. PMID:23679824

Migliore, Agostino; Nitzan, Abraham

2013-06-26

145

Contact angle hysteresis and pinning at periodic defects in statics.  

PubMed

This article deals with the theoretical prediction of the wetting hysteresis on nonideal solid surfaces in terms of the surface heterogeneity parameters. The spatially periodical chemical heterogeneity is considered. We propose precise definitions for both the advancing and the receding contact angles for the Wilhelmy plate geometry. It is well known that in such a system, a multitude of metastable states of the liquid meniscus occurs for each different relative position of the defect pattern on the plate with respect to the liquid level. As usual, the static advancing and receding angles are assumed to be a consequence of the preceding contact line motion in the respective direction. It is shown how to select the appropriate states among all metastable states. Their selection is discussed. The proposed definitions are applicable to both the static and the dynamic contact angles on heterogeneous surfaces. The static advancing and receding angles are calculated for two examples of periodic heterogeneity patterns with sharp borders: the horizontal alternating stripes of a different wettability (studied analytically) and the doubly periodic pattern of circular defects on a homogeneous base (studied numerically). The wetting hysteresis is determined as a function of the defect density and the spatial period. A comparison with the existing results is carried out. PMID:25122314

Iliev, Stanimir; Pesheva, Nina; Nikolayev, Vadim S

2014-07-01

146

Perceptual hysteresis as a marker of perceptual inflexibility in schizophrenia.  

PubMed

People with schizophrenia are known to exhibit difficulties in the updating of their current belief states even in the light of disconfirmatory evidence. In the present study we tested the hypothesis that people with schizophrenia could also manifest perceptual inflexibility, or difficulties in the updating of their current sensory states. The presence of perceptual inflexibility might contribute both to the patients' altered perception of reality and the formation of some delusions as well as to their social cognition deficits. Here, we addressed this issue with a protocol of auditory hysteresis, a direct measure of sensory persistence, on a population of stabilized antipsychotic-treated schizophrenia patients and a sample of control subjects. Trials consisted of emotional signals (i.e., screams) and neutral signals (i.e., spectrally-rotated versions of the emotional stimuli) progressively emerging from white noise - Ascending Sequences - or progressively fading away in white noise - Descending Sequences. Results showed that patients presented significantly stronger hysteresis effects than control subjects, as evidenced by a higher rate of perceptual reports in Descending Sequences. The present study thus provides direct evidence of perceptual inflexibility in schizophrenia. PMID:25147080

Martin, Jean-Rémy; Dezecache, Guillaume; Pressnitzer, Daniel; Nuss, Philippe; Dokic, Jérôme; Bruno, Nicolas; Pacherie, Elisabeth; Franck, Nicolas

2014-11-01

147

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

148

Contact angle hysteresis and pinning at periodic defects in statics  

NASA Astrophysics Data System (ADS)

This article deals with the theoretical prediction of the wetting hysteresis on nonideal solid surfaces in terms of the surface heterogeneity parameters. The spatially periodical chemical heterogeneity is considered. We propose precise definitions for both the advancing and the receding contact angles for the Wilhelmy plate geometry. It is well known that in such a system, a multitude of metastable states of the liquid meniscus occurs for each different relative position of the defect pattern on the plate with respect to the liquid level. As usual, the static advancing and receding angles are assumed to be a consequence of the preceding contact line motion in the respective direction. It is shown how to select the appropriate states among all metastable states. Their selection is discussed. The proposed definitions are applicable to both the static and the dynamic contact angles on heterogeneous surfaces. The static advancing and receding angles are calculated for two examples of periodic heterogeneity patterns with sharp borders: the horizontal alternating stripes of a different wettability (studied analytically) and the doubly periodic pattern of circular defects on a homogeneous base (studied numerically). The wetting hysteresis is determined as a function of the defect density and the spatial period. A comparison with the existing results is carried out.

Iliev, Stanimir; Pesheva, Nina; Nikolayev, Vadim S.

2014-07-01

149

Hysteresis Modeling and Inverse Feedforward Control of an AFM Piezoelectric Scanner Based on Nano Images  

E-print Network

Hysteresis Modeling and Inverse Feedforward Control of an AFM Piezoelectric Scanner Based on Nano of micro/nano technology. As a critical part of AFM system, the piezoelectric scanner exists many defects in this paper possess a good performance for AFM nano imaging. Index Terms-- Hysteresis modeling, feedforward

Li, Yangmin

150

Extension of Hysteresis operators of Preisach-type to real, Lebesgue measurable  

E-print Network

Extension of Hysteresis operators of Preisach-type to real, Lebesgue measurable functions R. Iyer to real, Lebesgue measurable functions is then obtained in the standard manner using the re-defined Play operators. Key words: Hysteresis operators of Preisach type, Lebesgue measurable functions. PACS: 75.60.-d

Iyer, Ram Venkataraman

151

Density hysteresis of heavy water confined in a nanoporous silica matrix  

E-print Network

Density hysteresis of heavy water confined in a nanoporous silica matrix Yang Zhanga,b , Antonio 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 promi- nent hysteresis phenomenon

Chen, Sow-Hsin

152

Hysteresis Response of Lead Zirconate—Lead Nickel Niobate Ferroelectric Ceramic Under Compressive Stress  

Microsoft Academic Search

In this work, PZ–PNN ceramic was prepared by a columbite method and sintered at optimum temperature. The effect of uniaxial compressive stress on the hysteresis properties of PZ–PNN ceramics is investigated. The hysteresis loop and ferroelectric properties under the compressive stress of the ceramics are observed at stress up to 100 MPa using a compressometer in conjunction with a modified

W. C. Vittayakorn; N. Vittayakorn

2009-01-01

153

Numerical Analysis of Hysteresis and Eddy Current Losses in Solid Cylindrical Rods of No. 1010 Steel  

Microsoft Academic Search

A procedure is given which utilizes the digital computer to solve eddy current loss and hysteresis loss problems. The relationship between flux density and magnetic intensity is taken from the actual magnetization curve and major hysteresis loop, thus eliminating the approximations employed in most previous investigations. The nonlinear partial differential equations are replaced by finite difference equations and solved by

Marshall Abrams; Donald Gillott

1967-01-01

154

Modeling and control of a piezoelectric actuator driven system with asymmetric hysteresis  

Microsoft Academic Search

This study describes the high-precision positioning control of a system with asymmetric hysteresis. A switching system concept is adopted to describe the Preisach-type hysteresis, and a systematic modeling procedure is established to obtain the parameters of the system. A piezoelectric actuator system driven by a voltage amplifier is used to verify the modeling accuracy. A control structure, comprising a feedforward

Ming-Jyi Jang; Chieh-Li Chen; Jie-Ren Lee

2009-01-01

155

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

E-print Network

from a PMN­PT­BT actuator operating at a temperature within the ferroelectric regime. Keywords: Domain of these materials in high performance actuator design. The nature of hysteresis models for ferroelectric materialsA Domain Wall Model for Ferroelectric Hysteresis Ralph C. Smith 1 and Craig L. Hom 2 1 Center

156

Modeling and measurement of hysteresis of ferroelectric actuators considering time-dependent behavior  

Microsoft Academic Search

We present a model for the simulation of ferroelectric hysteresis loops. It is based on the Preisach operator and takes advantage of an analytic weight function for the underlying fundamental switching operators. The five independent parameters describing this weight function are determined for a discoidal piezoceramic actuator by adapting the model output to measurements of the polarization. Further hysteresis simulations,

F. Wolf; A. Sutor; S. J. Rupitsch; R. Lerch

2010-01-01

157

A Domain Wall Model for Ferroelectric Hysteresis Ralph C. Smith1 and Craig L. Hom2  

E-print Network

from a PMN-PT-BT actuator operating at a temperature within the ferroelectric regime. Keywords: Domain of these materials in high performance actuator design. The nature of hysteresis models for ferroelectric materialsA Domain Wall Model for Ferroelectric Hysteresis Ralph C. Smith1 and Craig L. Hom2 1Center

158

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

E-print Network

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

Sethna, James P.

159

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

E-print Network

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

Sethna, James P.

160

Manuscript bleed-through removal via hysteresis thresholding Rolando Estrada and Carlo Tomasi  

E-print Network

Manuscript bleed-through removal via hysteresis thresholding Rolando Estrada and Carlo Tomasi@cs.duke.edu Abstract Many types of degradation can render ancient manuscripts very hard to read. In bleed, we propose hysteresis thresholding to greatly reduce bleed-through. Thresholding alone cannot

Tomasi, Carlo

161

Hysteresis Caused by Water Molecules in Carbon Nanotube Field-Effect  

E-print Network

commonly comprise nanotubes lying on SiO2 surfaces exposed to the ambient environment. It is shown here structure similar to that in Figure 1a) exhibiting hysteresis in current versus gate-voltage (Si as back-gate nanotubes, or traps at the SiO2/Si interface.11,12,14 No dependence of the hysteresis on chemical

Javey, Ali

162

An investigation on the hysteresis characteristics of an automotive air spring  

Microsoft Academic Search

Hysteresis is one of major properties of air spring during its compression and rebounding sequences. This study shows hysteresis property of air spring theoretically and experimentally. At first, the theoretical model of the air spring was developed, considering the factor of heat exchange. And then experiments of force responses with displacement excitation signal of various frequencies were implemented. The simulations

H. Liu; J. C. Lee

2007-01-01

163

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

E-print Network

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

Tan, Xiaobo

164

Characterization of hysteresis in magnetic systems: A Preisach approach  

NASA Astrophysics Data System (ADS)

The phenomenon of hysteresis is perhaps the most widely recognized microscopic manifestation of magnetic ordering, and is the principal feature which is responsible for technologically-oriented applications of magnetic materials such as permanent magnets and recording media. Interest in a phenomenological model of hysteresis originally proposed by Preisach in 1935 has been renewed recently, particularly in engineering applications, such as the characterization of magnetic recording media and magnetostrictive materials. Thus, a rigorous assessment of the capabilities and limitations of the Preisach model for characterizing magnetic materials is of considerable importance from both fundamental and technological perspectives. The fundamental characteristics of hysteresis are discussed and a theoretical background for the processes involved in magnetic systems is established. A generalized version of the scalar Preisach model, which includes original contributions, is developed to extend the model's abilities to describe the effects of the structure of the initially demagnetized state, the presence and nature of interactions, the system's coercive field distribution, and especially, the effects of temperature and experimental wart time, on the observed hysteretic properties of a variety of magnetic systems including spin glasses, ferromagnets, ferrimagnets, and superparamagnets. The moment and remanence of magnetic systems are measured as a function of applied field and temperature, using both a vibrating sample magnetometer (VSM) and a SQUID-based magnetometer. A Preisach analysis of the data is used to characterize the irreversible response of six magnetic systems: CrO 2 audio tape; magnetoferritin; a Nd2Fe14B permanent magnet; a floppy disk medium; and longitudinal and perpendicular cobalt-chromium-based hard disk materials. The ambiguous nature of tools presently used to analyze the nature of magnetic systems, such as the application of Henkel plots to the analysis of interaction effects, is demonstrated and alternative Preisach-based analysis schemes are presented. The physical significance of parameters, which emerged from the Preisach calculations, is discussed in detail and modifications are proposed to model this array of real magnetic systems. These changes to the scalar Preisach model extend its capabilities, while maintaining the inherent simplicity of a scalar model. Limitations of the model are also discussed critically, and suggestions for future generalizations are made.

Mitchler, Patricia Darlene

165

Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis.  

PubMed

Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis for probe liquids were prepared by chemical vapor deposition (CVD) of bis((tridecafluoro-1,1,2,2,-tetrahydrooctyl)-dimethylsiloxy)methylsilane (CF(3)(CF(2))(5)CH(2)CH(2)Si(CH(3))(2)O)(2)SiCH(3)H, (R(F)Si(Me)(2)O)(2)SiMeH). Oxidized aluminum surfaces were prepared by photooxidation/cleaning of sputter-coated aluminum on silicon wafers (Si/Al(Al(2)(O(3)))) using oxygen plasma. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that this facile CVD method produces a monolayer with a thickness of 1.1 nm on the Si/Al(Al(2)(O(3))) surface without a discernible change in surface morphology. After monolayer deposition, the hydrophilic Si/Al(Al(2)(O(3))) surface became both hydrophobic and oleophobic and exhibited essentially no contact angle hysteresis for water and n-hexadecane (advancing/receding contact angles (theta(A)/theta(R)) = 110 degrees/109 degrees and 52 degrees/50 degrees, respectively). Droplets move very easily on this surface and roll off of slightly tilted surfaces, independently of the contact angle (which is a practical definition of ultralyophobic). A conventional fluoroalkylsilane monolayer was also prepared from 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CF(3)(CF(2))(7)CH(2)CH(2)Si(OCH(3))(3), R(F)Si(OMe)(3)) for comparison. The theta(A)/theta(R) values for water and n-hexadecane are 121 degrees/106 degrees and 76 degrees/71 degrees, respectively. The larger hysteresis values indicate the "pinning" of probe liquids, even though advancing contact angles are larger than those of the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers. The (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers have excellent hydrolytic stability in water. We propose that the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers are flexible and liquidlike and that drops in contact with these surfaces experience very low energy barriers between metastable states, leading to the formation of nonhysteretic ultralyophobic surfaces. PMID:20030348

Hozumi, Atsushi; McCarthy, Thomas J

2010-02-16

166

Power losses in thick steel laminations with hysteresis  

NASA Astrophysics Data System (ADS)

Magnetic power losses have been experimentally investigated and theoretically predicted over a range of frequencies (direct current—1.5 kHz) and peak inductions (0.5-1.5 T) in 1-mm-thick FeSi 2 wt. % laminations. The direct current hysteresis properties of the system are described by the Preisach model, with the Preisach distribution function reconstructed from the measurement of the recoil magnetization curve (Bp=1.7 T). On this basis, the time behavior of the magnetic induction vs frequency at different lamination depths is calculated by a finite element method numerical solution of Maxwell equations, which takes explicitly into account the Preisach model hysteretic B(H) relationship. The computed loop shapes are, in general, in good agreement with the measured ones. The power loss dependence on frequency is predicted and experimentally found to change from a ˜f3/2 to a ˜f2 law with increasing peak induction.

Appino, C.; Bertotti, G.; Bottauscio, O.; Fiorillo, F.; Tiberto, P.; Binesti, D.; Ducreux, J. P.; Chiampi, M.; Repetto, M.

1996-04-01

167

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

168

Mechanical Properties of Spider Dragline Silk: Humidity, Hysteresis, and Relaxation  

PubMed Central

Spider silk is well-known for its outstanding mechanical properties. However, there is a significant variation of these properties in literature and studies analyzing large numbers of silk samples to explain these variations are still lacking. To fill this gap, the following work examines the mechanical properties of major ampullate silk based on a large ensemble of threads from Nephila clavipes and Nephila senegalensis. In addition, the effect of relative humidity (RH) on the mechanical properties was quantified. The large effect of RH on the mechanical properties makes it plausible that the variation in the literature values can to a large extent be attributed to changes in RH. Spider silk's most remarkable property—its high tenacity—remains unchanged. In addition, this work also includes hysteresis as well as relaxation measurements. It is found that the relaxation process is well described by a stretched exponential decay. PMID:17766337

Vehoff, T.; Glišovi?, A.; Schollmeyer, H.; Zippelius, A.; Salditt, T.

2007-01-01

169

Transient hysteresis of storm tracks response to anthropogenic forcing variation  

NASA Astrophysics Data System (ADS)

In this work we consider midlatitude storm tracks of Northern Hemisphere. The storm tracks are the regions of strong baroclinicity with which surface cyclones are associated. The effect of increasing and following decreasing anthropogenic load on storm tracks activity was investigated. The global climate system model of intermediate complexity ("Planet Simulator", Fraedrich K. et al., 2005) was used for this study. Anthropogenic forcing was set according to continued till 4000 AD climatic scenario RCP8.5 with the reduction of anthropogenic load to preindustrial value at different intensities (100 and 1000 years). The transient hysteresis in dependence of storm tracks activity versus global atmospheric temperature was exhibited. Moreover, poleward shift of storm tracks with the anthropogenic forcing increase and their following backward shift with the anthropogenic forcing decrease was demonstrated. This work is partially supported by SB RAS project VIII.80.2.1, RFBR grant 13-05-12034, 13-05-00480, 14-05-00502.

Martynova, Yuliya; Krupchatnikov, Vladimir

2014-05-01

170

Micromagnetic simulations of hysteresis in an array of cobalt nanotubes  

NASA Astrophysics Data System (ADS)

Here we perform modeling of hysteresis measurements, described earlier by Crowley et al., of an array of cobalt nanotubes using a single infinite tube simulation. The modeling has been performed under the assumptions that (i) the long axis of the tube is the hard axis of the anisotropy and (ii) in the experiment we deal with a distribution of different tubes, each having a different anisotropy constant. The best fit to the experimental result is achieved using a log-normal anisotropy distribution, with a peak value close to -0.2 MJ/m 3. The distribution parameters are nearly the same for both experimental temperatures, Texp=1.8 and 300 K. These parameters are only weakly dependent on the tube-wall width and the material parameters.

Lebecki, K. M.; Kazakova, O.; Gutowski, M. W.

2008-02-01

171

The extrinsic hysteresis behavior of dilute binary ferrofluids.  

PubMed

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

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

2014-10-01

172

Causes of concentration\\/discharge hysteresis and its potential as a tool for analysis of episode hydrochemistry  

Microsoft Academic Search

Episodic variations in dissolved solutes are frequently complicated by a cyclical relationship between concentration and stream discharge. Established three-component models of runoff generation are used to explain this hysteresis effect and to illustrate how different component concentrations produce different hysteresis forms. It is demonstrated that a two-component model cannot reproduce all the hysteresis forms commonly observed. A method, based on

Christopher Evans; Trevor D. Davies

1998-01-01

173

SMA pseudo-elastic hysteresis with tension-compression asymmetry: explicit simulation based on elastoplasticity models  

NASA Astrophysics Data System (ADS)

SMA pseudo-elastic hysteresis with tension-compression asymmetry at finite deformation may be simulated by finite elastoplastic J 2-flow models with nonlinear combined hardening, in a direct, explicit sense with no reference to any phase variables. To this goal, a novel method of treating tension-compression asymmetry is proposed, and the hardening moduli are determined directly from any two given pairs of single-variable functions shaping non-symmetric hysteresis loops in uniaxial tension and compression so that the combined hardening model thus established can automatically exactly give rise to any given shapes of non-symmetric hysteresis loops. Numerical examples show good agreement with test data.

Wang, Xiao-Ming; Wang, Zhao-Ling; Xiao, Heng

2014-11-01

174

Enhancement of coil-stretch hysteresis by self-concentration in polymer solutions  

E-print Network

The effect of concentration on coil-stretch hysteresis in extensional flows of polymer solutions is examined with insights from Brownian dynamics simulations of isolated chains and scaling theory for non-dilute solutions. In the hysteresis regime, stretched molecules pervade larger volumes than equilibrium coils. For such chains, intermolecular overlap and hydrodynamic screening crossover set in at concentrations much smaller than the critical overlap concentration $c^\\ast$ for equilibrium coils. The width of the hysteresis window is consequently strongly enhanced around $c^\\ast$.

Ranganathan Prabhakar

2013-01-31

175

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

176

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

PubMed

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

Shigeno, Masanori; Kushida, Yo; Yamaguchi, Masahiko

2013-07-29

177

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

NASA Astrophysics Data System (ADS)

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

Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich

2015-01-01

178

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

SciTech Connect

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

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

2014-04-15

179

A current error space vector based hysteresis controller with constant switching frequency and simple online boundary computation for VSI fed IM drive  

Microsoft Academic Search

This paper proposes a simple current error space vector based hysteresis controller for two-level inverter fed Induction Motor (IM) drives. This proposed hysteresis controller retains all advantages of conventional current error space vector based hysteresis controllers like fast dynamic response, simple to implement, adjacent voltage vector switching etc. The additional advantage of this proposed hysteresis controller is that it gives

Rijil Ramchand; Chintan Patel; Anandarup Das; K. Sivakumar; K. Gopakumar; L. M. Patnaik

2010-01-01

180

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

E-print Network

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

Laughlin, David E.

181

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

182

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

183

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

184

Mixed convection on a horizontal surface within a partial enclosure: Hysteresis effects  

SciTech Connect

In this paper, the authors report results of a numerical study of mixed convection over a horizontal surface in a partially open adiabatic symmetric vertical channel for different enclosure configurations. Specifically, they study the effect of the height of the exit opening and the aspect ratio on the hysteresis effect observed in such enclosures. As w*, the ratio of the height of the exit opening to the height of the enclosure is increased, the extent of the hysteresis loop shifts. However, at a value of w* = 0.6, the hysteresis loop actually gets bigger. Moreover a periodic, unsteady behavior of the flow is also observed for low Reynolds number. As the aspect ratio (defined as the ratio of width to height of the enclosure) is decreased, the hysteresis loop shifts again. These interesting flow characteristics and associated heat transfer are discussed in detail. The paper also reports the effect of outlet boundary conditions on the flow and temperature fields.

Calmidi, V.V.; Mahajan, R.L. [Univ. of Colorado, Boulder, CO (United States). Dept. of Mechanical Engineering

1995-12-31

185

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

E-print Network

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

Boyer, Edmond

186

Force chains and hysteresis in a 2D granular piston  

NASA Astrophysics Data System (ADS)

We present photoelastic studies of force distributions and propagation in a 2D granular piston.footnote E. Kolb, et. al. Europhys. J. B. 8, 483-491 (1999). The particles, ~ 1/2 cm disks, are confined by rigid sidewalls and pushed against gravity by a piston at constant velocity in the range 10-150 ? m/s. Friction prevents the free rotation and displacement of particles within the bulk of the material and leads to the buildup of stress chains resisting motion. The local and global stress within the granular material can be extracted by placing the experiment between complimentary circular polarizers. We find that the initial preparation (where the particles rain down in bulk) gives a stress minimum in the middle and edges, while the stress is polarized and maximal along each sidewall. The 2D pressure saturates at a depth ~ 1/2 width, and uniform compressive loads show hysteresis within the bulk. Under shear, we present evidence of stick-slip dynamics and large-scale convection when the particles can mobilize after dilation.

Hartley, R. R.; Behringer, R. P.; Kolb, E.; Ovarlez, G.; Clement, E.

2001-11-01

187

Avalanches and hysteresis in frustrated superconductors and XY spin glasses  

NASA Astrophysics Data System (ADS)

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

Sharma, Auditya; Andreanov, Alexei; Müller, Markus

2014-10-01

188

Avalanches and hysteresis in frustrated superconductors and XY spin glasses.  

PubMed

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

Sharma, Auditya; Andreanov, Alexei; Müller, Markus

2014-10-01

189

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

190

Hysteresis of ligand binding in CNGA2 ion channels  

PubMed Central

Tetrameric cyclic nucleotide-gated (CNG) channels mediate receptor potentials in olfaction and vision. The channels are activated by the binding of cyclic nucleotides to a binding domain embedded in the C terminus of each subunit. Here using a fluorescent cGMP derivative (fcGMP), we show for homotetrameric CNGA2 channels that ligand unbinding is ~50 times faster at saturating than at subsaturating fcGMP. Analysis with complex Markovian models reveals two pathways for ligand unbinding; the partially liganded open channel unbinds its ligands from closed states only, whereas the fully liganded channel reaches a different open state from which it unbinds all four ligands rapidly. Consequently, the transition pathways for ligand binding and activation of a fully liganded CNGA2 channel differ from that of ligand unbinding and deactivation, resulting in pronounced hysteresis of the gating mechanism. This concentration-dependent gating mechanism allows the channels to respond to changes in the cyclic nucleotide concentration with different kinetics. PMID:24287615

Nache, Vasilica; Eick, Thomas; Schulz, Eckhard; Schmauder, Ralf; Benndorf, Klaus

2013-01-01

191

Magnetic hysteresis of cerium doped bismuth ferrite thin films  

NASA Astrophysics Data System (ADS)

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

Gupta, Surbhi; Tomar, Monika; Gupta, Vinay

2015-03-01

192

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

193

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

194

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

Microsoft Academic Search

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

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

1991-01-01

195

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

PubMed Central

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

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

2014-01-01

196

Constricted hysteresis loop and microstructure of Cu-Mn-Al alloys  

Microsoft Academic Search

The microstructure of 44.7 Cu-20.6 Mn-34.7 Al (at.%) alloy, which exhibits a remarkable constricted hysteresis loop in the as-cast state, has been investigated by transmission electron microscopy. It has been found that the constricted hysteresis loop is caused by the nonuniform precipitation of nonmagnetic Cu9Al4 particles in the ferromagnetic Cu2MnAl matrix.

K. Narita; S. Koga

1977-01-01

197

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

198

Experimental characterization and modeling of rate-dependent asymmetric hysteresis of magnetostrictive actuators  

NASA Astrophysics Data System (ADS)

The hysteresis nonlinearities of a magnetostrictive actuator were characterized under different amplitudes of simple and complex harmonic excitations over a wide range of frequencies (10-200 Hz) and magnetic bias levels (35-75 kA m-1). The measured data revealed asymmetric output-input characteristics and strong dependence on the magnetic bias, amplitude and frequency of the input. Output saturation was also observed under moderate to high amplitude excitations. A phenomenological hysteresis model is proposed in this study to model the hysteresis nonlinearities of a magnetostrictive actuator. A rate-dependent Prandtl-Ishlinskii model integrating a memoryless function of deadband operator was subsequently formulated to describe both the rate dependence and the asymmetric hysteresis loops of the magnetostrictive actuator in addition to the output saturation. Comparisons of the integrated Prandtl-Ishlinskii model responses with the measured data suggested that the model can effectively describe the nonlinear hysteresis properties of the magnetostrictive actuator over a broad range of excitation amplitudes and frequencies. The inverse of the proposed rate-dependent Prandtl-Ishlinskii model can be obtained analytically. Then, the inverse model can be applied as feedforward compensator for compensation of asymmetric rate-dependent hysteresis nonlinearities without using feedback control techniques.

Aljanaideh, Omar; Rakheja, Subhash; Su, Chun-Yi

2014-03-01

199

Magnetoimpedance hysteresis in amorphous microwires induced by core-shell interaction  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

200

Modeling and inverse feedforward control for conducting polymer actuators with hysteresis  

NASA Astrophysics Data System (ADS)

Conducting polymer actuators are biocompatible with a small footprint, and operate in air or liquid media under low actuation voltages. This makes them excellent actuators for macro- and micro-manipulation devices, however, their positioning ability or accuracy is adversely affected by their hysteresis non-linearity under open-loop control strategies. In this paper, we establish a hysteresis model for conducting polymer actuators, based on a rate-independent hysteresis model known as the Duhem model. The hysteresis model is experimentally identified and integrated with the linear dynamics of the actuator. This combined model is inverted to control the displacement of the tri-layer actuators considered in this study, without using any external feedback. The inversion requires an inverse hysteresis model which was experimentally identified using an inverse neural network model. Experimental results show that the position tracking errors are reduced by more than 50% when the hysteresis inverse model is incorporated into an inversion-based feedforward controller, indicating the potential of the proposed method in enabling wider use of such smart actuators.

Wang, Xiangjiang; Alici, Gursel; Tan, Xiaobo

2014-02-01

201

State transitions, hysteresis, and control parameters on DIII-D  

SciTech Connect

The theory of turbulence decorrelation by ExB velocity shear is the leading candidate to explain the changes in turbulence and transport that are seen at the plasma edge at the L to H transition. Based on this, a key question is: What are the conditions or control parameters needed to begin the formation of the E{sub r} shear layer and thus trigger the L to H transition? On the DIII-D tokamak, the authors are attacking this question both through direct tests of the various theories and by trying to gain insight into the fundamental physics by investigating the control parameters which have a major effect on the power threshold. In this paper the authors describe results of studies on oscillating discharges where the plasma transitions continuously between L and H states. By following the dynamics of the plasma state through the forward and back transitions, they can represent the evolution of various control parameter candidates as a trajectory in various parametric spaces. The shape of these control curves can illustrate the specific nonlinearities governing the L-H transition problem, and under the proper conditions may be interpreted in the context of various phase-transition based models. In particular, the hysteresis exhibited in the various curves may help to clarify causality (what are the critical parameters) and may serve as tests of the models, given sufficient experimental accuracy. At present they are looking at T{sub e}, E{sub r} and ballooning/diamagnetic parameters as possible control parameter candidates.

Thomas, D.M.; Groebner, R.J.; Carlstrom, T.N.; Osborne, T.H.; Petrie, T.W.

1998-07-01

202

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

203

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

204

Extension of the stability of motions in a combustion chamber by non- linear active control based on hysteresis  

SciTech Connect

This report presents the first quantitative data establishing the details of hysteresis whose existence in dynamical behavior was reported by Sterling and Zukoski. The new idea was demonstrated that the presence of dynamical hysteresis provides opportunity for a novel strategy of active nonlinear control of unsteady motions in combustors. A figure shows the hysteresis exhibited for the amplitude of pressure oscillations as a function of equivalence ratio in a combustor having a recirculation zone, in this case a dump combustor.

Knoop, P.; Culick, F.E.C.; Zukoski, E.E.

1996-07-01

205

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

206

Climate Hysteresis for Planets Orbiting Stars of Different Spectral Type  

NASA Astrophysics Data System (ADS)

Planetary climate can be affected by the interaction of the host star spectral energy distribution with the wavelength-dependent reflectivity of ice and snow. We have explored this effect with a hierarchy of models. Results from both one-dimensional (1-D) radiative transfer and energy balance models and a three-dimensional (3-D) general circulation model indicate that terrestrial planets orbiting stars with higher near-UV radiation exhibit a stronger ice-albedo feedback. We found that ice extent is much greater on a planet orbiting an F-dwarf star than on a planet orbiting a G- or M-dwarf star at an equivalent flux distance, assuming fixed CO2 (present atmospheric level on Earth). The surface ice-albedo feedback effect becomes less important at the outer edge of the habitable zone for main-sequence stars, where the maintenance of surface liquid water requires high atmospheric CO2 concentrations. We show that ?3-10 bar of CO2 will entirely mask the climatic effect of ice and snow, leaving the outer limits of the habitable zone unaffected by the spectral dependence of water ice and snow albedo. However, less CO2 is needed to maintain open water for a planet orbiting an M-dwarf star than would be the case for hotter main-sequence stars. Both entrance into and exit out of a snowball state are sensitive to host star spectral energy distribution. Our simulations indicate a smaller climate hysteresis on M-dwarf planets, as measured by the range of instellation that permits multiple stable ice line latitudes. While M-dwarf planets appear less susceptible to snowball episodes than G- or F-dwarf planets over the course of their evolution, any snowball planets that are found orbiting M-dwarf stars may more easily melt out of these states as stellar luminosity increases over time. This effect is due to the lower-albedo ice on M-dwarf planets which, compounded with near-IR absorption by atmospheric gases, reduces the amount of increased stellar insolation, or “instellation”, necessary to melt these planets out of a snowball state.

Shields, Aomawa; Meadows, V.; Bitz, C.; Pierrehumbert, R.; Joshi, M.; Robinson, T.; Planetary Laboratory, Virtual

2013-10-01

207

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

NASA Astrophysics Data System (ADS)

Using Monte Carlo simulations, we study the hysteresis in the unzipping of double-stranded DNA whose ends are subjected to a time-dependent periodic force with frequency (? ) and amplitude (G ). For the static force, i.e., ? ?0 , the DNA is in equilibrium with no hysteresis. On increasing ? , the area of the hysteresis loop initially increases and becomes maximum at frequency ?*(G ) , which depends on the force amplitude G . If the frequency is increased further, we find that for lower amplitudes the loop area decreases monotonically to zero, but for higher amplitudes it has an oscillatory component. The height of subsequent peaks decreases, and finally the loop area becomes zero at very high frequencies. The number of peaks depends on the length of the DNA. We give a simple analysis to estimate the frequencies at which maxima and minima occur in the loop area. We find that the area of the hysteresis loop scales as 1 /? in the high-frequency regime, whereas it scales as G??? with exponents ? =1 and ? =5 /4 at low frequencies. The values of the exponents ? and ? are different from the exponents reported earlier based on the hysteresis of small hairpins.

Kapri, Rajeev

2014-12-01

208

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

209

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

210

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

211

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

E-print Network

We study, by using Monte Carlo simulations, the hysteresis in unzipping of a double stranded DNA whose ends are subjected to a time dependent periodic force with frequency ($\\omega$) and amplitude ($G$). For the static force, i.e., $\\omega \\to 0$, the DNA is in equilibrium with no hysteresis. On increasing $\\omega$, the area of the hysteresis loop initially increases and becomes maximum at frequency $\\omega^{*}(G)$, which depends on the force amplitude $G$. If the frequency is further increased, we find that for lower amplitudes the loop area decreases monotonically to zero, but for higher amplitudes it has an oscillatory component. The height of subsequent peaks decrease and finally the loop area becomes zero at very high frequencies. The number of peaks depend on the length of the DNA. We give a simple analysis to estimate the frequencies at which maxima and minima occurs in the loop area. We find that the area of the hysteresis loop scales as $1/\\omega$ in high frequency regime whereas, it scales as $G^{\\alpha} \\omega^{\\beta}$ with exponents $\\alpha =1$ and $\\beta = 5/4$ at low frequencies. The values of the exponents $\\alpha$ and $\\beta$ are different from the exponents reported earlier based on hysteresis of small hairpins.

Rajeev Kapri

2014-09-30

212

Microstructure and hysteresis curves of the barium hexaferrite from co-precipitation by organic agent  

NASA Astrophysics Data System (ADS)

This work correlates the magnetic hysteresis curves to the microstructure of the sintered polycrystalline barium hexaferrite discs produced from co-precipitated barium and iron citrates. Citric acid was used as the organic precipitating agent. Thermogravimetric and differential thermal analyses were performed on the co-precipitated product in order to guide its calcination into barium hexaferrite crystals, which was confirmed by means of the X-ray fluorescence and X-ray diffraction. After that, the hexaferrite powder was pressed in a steel die and submitted to firing in air at various temperatures. The final ceramic pieces were characterized by means of scanning electron microscopy and magnetic hysteresis grapher. The obtained results indicate a strong effect of the firing temperature on the microstructure, which in turn affected the magnetic hysteresis curve.

Ogasawara, T.; Oliveira, M. A. S.

2000-07-01

213

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

214

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

SciTech Connect

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

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

2008-10-14

215

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

216

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

217

Adaptive neural control for a class of nonlinear time-varying delay systems with unknown hysteresis.  

PubMed

This paper investigates the fusion of unknown direction hysteresis model with adaptive neural control techniques in face of time-delayed continuous time nonlinear systems without strict-feedback form. Compared with previous works on the hysteresis phenomenon, the direction of the modified Bouc-Wen hysteresis model investigated in the literature is unknown. To reduce the computation burden in adaptation mechanism, an optimized adaptation method is successfully applied to the control design. Based on the Lyapunov-Krasovskii method, two neural-network-based adaptive control algorithms are constructed to guarantee that all the system states and adaptive parameters remain bounded, and the tracking error converges to an adjustable neighborhood of the origin. In final, some numerical examples are provided to validate the effectiveness of the proposed control methods. PMID:25420237

Liu, Zhi; Lai, Guanyu; Zhang, Yun; Chen, Xin; Chen, Chun Lung Philip

2014-12-01

218

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

219

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

220

A model for the hysteresis observed in gating of lysenin channels.  

PubMed

The pore-forming toxin lysenin self-inserts to form conductance channels in natural and artificial lipid membranes containing sphingomyelin. The inserted channels exhibit voltage regulation and hysteresis of the macroscopic current during the application of positive periodic voltage stimuli. We explored the bi-stable behavior of lysenin channels and present a theoretical approach for the mechanism of the hysteresis to explain its static and dynamic components. This investigation develops a model to incorporate the role of charge accumulation on the bilayer lipid membrane in influencing the channel conduction state. Our model is supported by experimental results and also provides insight into the temperature dependence of lysenin channel hysteresis. Through this work we gain perspective into the mechanism of how the response of a channel protein is determined by previous stimuli. PMID:24075493

Krueger, Eric; Al Faouri, Radwan; Fologea, Daniel; Henry, Ralph; Straub, David; Salamo, Greg

2013-12-31

221

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

222

Improving positioning accuracy of piezoelectric actuators by feedforward hysteresis compensation based on a new mathematical model  

NASA Astrophysics Data System (ADS)

The hysteresis characteristic of piezoelectric actuators is one of the major deficiencies in a wide variety of precise tracking positioning controls. This article proposes a control method for piezoelectric actuator based on a proportional integral differential (PID) feedback controller with a feedforward compensation. The hysteresis phenomenon of a piezoelectric actuator is described in the feedforward loop by using a new mathematical model. Finally, some tracking control experiments for a desired sinusoidal trajectory are performed according to the proposed control method. The experimental results demonstrate that the positioning precision is noticeably improved by adding the feedforward compensation based on the new hysteresis model. The maximum error in tracking the sinusoidal signal is lowered about one order of magnitude in comparison with a regular PID controller without any feedforward compensation.

Ru, Changhai; Sun, Lining

2005-09-01

223

Hysteresis Characteristics of Flux-lock Type SFCL with Series Connection of Two Coils  

NASA Astrophysics Data System (ADS)

Since the saturation of the iron core comprising the flux-lock type superconducting fault current limiter (SFCL) with series connection of two coils can prevent its effective fault current limiting operation immediately after a fault accident, the flux-lock type SFCL's design considering the hysteresis characteristics is essential. For the analysis on the hysteresis characteristics of the SFCL during the fault period, its equivalent circuit for the transformer with the nonlinear exciting branch was drawn. Through the analysis on the SFCL's hysteresis curves, which were obtained from the SFCL's fault current limiting experiments based on its equivalent circuit, the winding direction of two coils, one of the design conditions, to suppress the saturation of the iron core comprising the flux-lock type SFCL with series connection of two coils was discussed.

Lim, S. H.; Ko, S. C.; Han, T. H.

224

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

NASA Astrophysics Data System (ADS)

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

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

1999-04-01

225

Hysteresis between coral reef calcification and the seawater aragonite saturation state  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

226

A neural model of hysteresis in amorphous materials and piezoelectric materials  

NASA Astrophysics Data System (ADS)

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

Ma, Lianwei; Shen, Yu

2014-08-01

227

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

228

Inverse compensation for hysteresis in piezoelectric actuator using an asymmetric rate-dependent model  

NASA Astrophysics Data System (ADS)

This paper presents a modified Bouc-Wen model for asymmetric rate-dependent hysteresis in piezoelectric actuator. On this basis, we develop a new digital inverse controller with a simple structure cascaded in the feedforward path for piezoelectric actuator. In order to eliminate modeling errors and parameter uncertainties, the developed inverse controller is combined with a feedback loop to establish a hybrid control scheme. In our experiments, the proposed model together with the developed hybrid control scheme has shown significantly reduced tracking errors caused by asymmetric rate-dependent hysteresis in piezoelectric actuator.

Li, Wei; Chen, Xuedong; Li, Zilong

2013-11-01

229

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

230

IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 17, NO. 4, JULY 2002 453 A Static Hysteresis Model for Power Ferrites  

E-print Network

for Power Ferrites Paiboon Nakmahachalasint, Student Member, IEEE, Khai D. T. Ngo, Senior Member, IEEE manganese­zinc (MnZn) ferrites. The procedures to extract the model parameters from voltage and current and minor hysteresis loops of three commercial power ferrites. Index Terms--Domain-wall, hysteresis modeling

Vu-Quoc, Loc

231

Modeling of Nonlinear Hysteresis in Elastomers H.T. Banks, Gabriella A. Pinter and Laura K. Potter  

E-print Network

Modeling of Nonlinear Hysteresis in Elastomers H.T. Banks, Gabriella A. Pinter and Laura K. Potter discuss issues related to modeling of nonlinearities and hysteresis arising in a class of lled elastomers required for a smart elastomer technology. Smart material structures and uids 11 , 23 are generally

232

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

233

Analysis of thermal hysteresis protein hydration using the random network model  

Microsoft Academic Search

The hydration of polar and apolar groups can be explained quantitatively, via the random network model of water, in terms of differential distortions in first hydration shell water–water hydrogen bonding angle. This method of analyzing solute induced structural distortions of water is applied to study the ice-binding type III thermal hysteresis protein. The analysis reveals subtle but significant differences in

Kelly Ryan Gallagher; Kim A. Sharp

2003-01-01

234

HYSTERESIS MODELLING FOR A MR DAMPER Jorge de-J. Lozoya-Santos1  

E-print Network

of a commercial Magneto-Rheological (MR) damper is exploited for identification of a Hysteresis-based Control The Magneto-Rheological (MR) damper is a non-linear component with dissipative capability used in the con a certain magnetic field is applied to the MR fluids, the particles in the fluids are polarized

Boyer, Edmond

235

Modeling and Identification of Elastic Robot Joints With Hysteresis and Backlash  

Microsoft Academic Search

This paper presents a novel approach to the modeling and identification of elastic robot joints with hysteresis and backlash. The model captures the dynamic behavior of a rigid robotic manipulator with elastic joints. The model includes electromechanical submodels of the motor and gear from which the relationship between the applied torque and the joint torsion is identified. The friction behavior

Michael Ruderman; Frank Hoffmann; Torsten Bertram

2009-01-01

236

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

Microsoft Academic Search

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

THOMAS PAREÂ; ARASH HASSIBI

2001-01-01

237

The field and temperature dependence of hysteresis loops in P(VDF-TrFE) copolymer films  

NASA Astrophysics Data System (ADS)

The ferroelectric hysteresis loops of poly(vinylidene fluoride/trifluoethylene) [P(VDF-TrFE)] copolymer films are investigated as a function of external field and temperature. Starting from a plateau at the low frequency side the coercive field increases with increasing frequency. It exhibits a maximum in the kHz-range and decreases then. The remanent polarization is almost constant at low frequencies and decreases above the kHz-range. For a constant frequency, the coercive field increases with increasing the amplitude of the external field. Furthermore, the hysteresis loops at different temperatures at a given frequency and amplitude exhibit a linear decrease of coercive field with increasing temperature. A double hysteresis loop is observed close to the Curie point and a sharp jump of the remanent polarization is obtained in samples as thick as 600 nm indicating a first order phase transition. For samples as thin as 90 nm, the double hysteresis loop of the polarization is absent and the change of remanent polarization dependent on temperature is smoother. The above experimental results can be explained and simulated in the Weiss mean field model. The simulation results are compared with the experiments and show a good consistency.

Mai, Manfang; Leschhorn, Andreas; Kliem, Herbert

2015-01-01

238

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

239

A Wind-Induced Thermohaline Circulation Hysteresis and Millennial Variability Regimes  

E-print Network

A Wind-Induced Thermohaline Circulation Hysteresis and Millennial Variability Regimes YOSEF 12 December 2006) ABSTRACT The multiple equilibria of the thermohaline circulation (THC: used here of the wind stress amplitude. Starting with active winds and a thermally dominant thermohaline circulation

Tziperman, Eli

240

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

241

Capillary condensation, invasion percolation, hysteresis, and discrete memory R. A. Guyer  

E-print Network

Capillary condensation, invasion percolation, hysteresis, and discrete memory R. A. Guyer of the capillary condensation process, i.e., of adsorption-desorption isotherms, having only pore- pore and to a related model of interacting pore systems the random field Ising model . The capillary condensation model

242

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

E-print Network

simultaneously1,2,3,4,5 . The name spin ice comes from the fact that lowest energy states obey the ice ruleDynamics and hysteresis in square lattice artificial spin ice G. M. Wysin Department of Physics spin ice on a square lattice in two dimensions. Each island of the spin ice has a three

Wysin, Gary

243

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

244

Classical Prandtl-Ishlinskii modeling and inverse multiplicative structure to compensate hysteresis in piezoactuators  

E-print Network

the static hysteresis in smart material based actuators that is modeled by the Prandtl- Ishlinskii approach, ...) and advanced control laws (H, passivity,...) have been successfully used [6][7]. Its main advantages-st Institute, UMR CNRS-6174 / UFC / ENSMM / UTBM Automatic Control and Micro-Mechatronic Systems department (AS

Paris-Sud XI, Université de

245

Extension of hysteresis operators of Preisach-type to real, Lebesgue measurable functions  

Microsoft Academic Search

Functions in Llocp[0,?) where 1?p?? can be considered as inputs to linear systems. However, hysteresis operators of Preisach type have only been defined on much smaller space of regulated (or Baire) functions. In this paper, we re-define Play operators so that they are well defined for real valued measurable functions. We show that this definition coincides with the older definition

R. Iyer; D. Ekanayake

2008-01-01

246

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

E-print Network

effective is dictated by soil hydraulic properties and surrogates for atmospheric water vapor demandOnset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water] Estimation of water uptake by plants and subsequent water stress are complicated by the need to resolve

Katul, Gabriel

247

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

248

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

249

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

250

Scaling behavior of hysteresis in multilayer MoS2 field effect transistors  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

251

There and (slowly) back again: entropy-driven hysteresis in a model of DNA overstretching.  

PubMed

When pulled along its axis, double-stranded DNA elongates abruptly at a force of approximately 65 pN. Two physical pictures have been developed to describe this overstretched state. The first proposes that strong forces induce a phase transition to a molten state consisting of unhybridized single strands. The second picture introduces an elongated hybridized phase called S-DNA. Little thermodynamic evidence exists to discriminate directly between these competing pictures. Here we show that within a microscopic model of DNA we can distinguish between the dynamics associated with each. In experiment, considerable hysteresis in a cycle of stretching and shortening develops as temperature is increased. Since there are few possible causes of hysteresis in a system whose extent is appreciable in only one dimension, such behavior offers a discriminating test of the two pictures of overstretching. Most experiments are performed upon nicked DNA, permitting the detachment (unpeeling) of strands. We show that the long-wavelength progression of the unpeeled front generates hysteresis, the character of which agrees with experiment only if we assume the existence of S-DNA. We also show that internal melting can generate hysteresis, the degree of which depends upon the nonextensive loop entropy of single-stranded DNA. PMID:17981894

Whitelam, Stephen; Pronk, Sander; Geissler, Phillip L

2008-04-01

252

There and (Slowly) Back Again: Entropy-Driven Hysteresis in a Model of DNA Overstretching  

PubMed Central

When pulled along its axis, double-stranded DNA elongates abruptly at a force of ?65 pN. Two physical pictures have been developed to describe this overstretched state. The first proposes that strong forces induce a phase transition to a molten state consisting of unhybridized single strands. The second picture introduces an elongated hybridized phase called S-DNA. Little thermodynamic evidence exists to discriminate directly between these competing pictures. Here we show that within a microscopic model of DNA we can distinguish between the dynamics associated with each. In experiment, considerable hysteresis in a cycle of stretching and shortening develops as temperature is increased. Since there are few possible causes of hysteresis in a system whose extent is appreciable in only one dimension, such behavior offers a discriminating test of the two pictures of overstretching. Most experiments are performed upon nicked DNA, permitting the detachment (unpeeling) of strands. We show that the long-wavelength progression of the unpeeled front generates hysteresis, the character of which agrees with experiment only if we assume the existence of S-DNA. We also show that internal melting can generate hysteresis, the degree of which depends upon the nonextensive loop entropy of single-stranded DNA. PMID:17981894

Whitelam, Stephen; Pronk, Sander; Geissler, Phillip L.

2008-01-01

253

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

254

Hysteresis and Related Error Mechanisms in the NIST Watt Balance Experiment  

Microsoft Academic Search

The NIST watt balance experiment is being completely rebuilt after its 1998 determination of the Planck constant. That measurement yielded a result with an approximately 110 -7 relative standard uncertainty. Because the goal of the new incarnation of the experiment is a ten-fold decrease in uncertainty, it has been necessary to reexamine many sources of systematic error. Hysteresis effects account

Joshua P. Schwarz; Ruimin Liu; David B. Newell; Richard L. Steiner; Edwin R. Williams; Douglas Smith

2001-01-01

255

Optical bistability and hysteresis of a hybrid metal-semiconductor nanodimer  

Microsoft Academic Search

Optical response of an artificial composite nanodimer comprising a semiconductor quantum dot and a metal nanosphere is analyzed theoretically. We show that internal degrees of freedom of the system can manifest bistability and optical hysteresis as functions of the incident field intensity. We argue that these effects can be observed for real-world systems, such as a CdSe quantum dot and

A. V. Malyshev; V. A. Malyshev

2011-01-01

256

Hysteresis and the single-phase metal-insulator transition in switchable YHx films  

Microsoft Academic Search

Extraordinary large hysteresis effects in optical, electrical, and structural properties are observed in switchable mirrors based on thin yttrium hydride (YHx) films, deposited on quartz glass or sapphire. The pressure-composition isotherms of the YHx system between x=2 and 3 for absorption and desorption, determined electrochemically, differ by approximately three orders of magnitude. The optical transmittance exhibits a distinct minimum when

E. S. Kooij; Gogh van A. T. M; D. G. Nagengast; N. J. Koeman; R. P. Griessen

2000-01-01

257

A grounded-load charge amplifier for reducing hysteresis in piezoelectric tube scanners  

E-print Network

A grounded-load charge amplifier for reducing hysteresis in piezoelectric tube scanners A. J 2005 In this paper, a charge amplifier adapted for piezoelectric tube scanners is presented. Previous difficulty associated with piezoelectric tube scanners and piezoelectric actuators in general . When employed

Fleming, Andrew J.

258

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

259

An Analytical Description of Slow Hysteresis in Polarized Ferroelectric Ceramic Actuators  

Microsoft Academic Search

Recently, an existing system of electroelastic equations was extended to account for slow hysteretic effects in polarized ferroelectric ceramic plates by employing an internal variable in a thermodynamic state function. All material irreversibility was taken to be a consequence of the ferroelectric polarization-electric field irreversibility. Since only the slowest possible hysteresis is of concern, the evolution equation is ignored and

L. Huang; H. F. Tiersten

1998-01-01

260

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

E-print Network

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

Kapri, Rajeev

2014-01-01

261

Special hysteresis effects in N{sub 2}-sorption and mercury-porosimetry measurements  

SciTech Connect

Model pore structures were prepared from dispersions of submicron monodispersed silica particles by a sedimentation process. Ordered dense sphere packing structures were observed with scanning electron microscopy. Nitrogen sorption- as well as Hg-porosimetry measurements confirmed the calculated values of the pore openings in those structures. In Hg-porosimetry measurements a two step extrusion curve was observed, when the pore system was only partially filled during the intrusion process. This two step curve was not observed in case the pore system was filled with mercury to more than 95% during the intrusion run. The mercury porosimetry results can be interpreted in terms of the coexistence of octahedral and tetrahedral voids (pores) in the examined sphere packing structure and their special arrangement within the structure (connectivity). Two models will be described to explain the general occurrence of hysteresis in Hg-porosimetry. The actual pore geometry is shown to have a profound influence on the hysteresis shape as well as a change in the contact angle (constant within each measurement) can result in totally different hysteresis curves. Nitrogen adsorption and desorption measurements on the same powders did not reveal any fine structure within the hysteresis range.

Giesche, H. [Alfred Univ., NY (United States). New York State Coll. of Ceramics

1996-12-31

262

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

E-print Network

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

Martcheva, Maia

263

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

PubMed Central

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

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

2013-01-01

264

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

265

PM motor sensorless position detection based on iron BH local hysteresis  

Microsoft Academic Search

A sensorless position detection technique for a permanent magnet (PM) motor with non-salient rotor is presented. It is shown that the phase self inductances and resistances measured at higher frequencies vary slightly with the rotor position. The origin of the variations is found in the iron B-H hysteresis characteristics. In order to exploit these small variations for the rotor position

Omar Scaglione; Miroslav Markovic; Yves Perriard

2009-01-01

266

Pore-scale mechanisms for hysteresis in capillary-dominated drainage and imbibition (Invited)  

NASA Astrophysics Data System (ADS)

Understanding the flow of two immiscible fluid phases through the pore space of rocks and soils is a complex problem involving fluid dynamics, surface science and geometry. Invariably one fluid, usually water, preferentially coats the solid surface. Of major interest, and a significant challenge for multiphase fluid modelling, is the fact that the flow displays hysteresis: the measured difference in pressure between fluids (the capillary pressure) is higher when the water is draining out than when it is imbibing back in. One consequence of this hysteresis include capillary trapping, of relevance to waterflooding oil recovery and geosequestration of CO¬2. While several models have attempted with mixed success to capture this hysteresis at the macro-scale, no consensus yet exists on its pore-scale causes. The current work makes use of X-ray micro-tomography (MCT) data to help identify resolve this question. We first enumerate the different mechanisms that have been proposed in the literature for this hysteresis. We break these mechanisms into two categories: local mechanisms that may occur inside a single geometric feature (such as a pore or throat) and those that may only be observed within some sort of labyrinth. Local mechanisms include contact angle hysteresis (induced by surface, chemistry surface roughness and/or interface pinning), the ink-bottle effect and geometric bistability associated with the stability of both main terminal menisci and arc menisci in a constrictive pore space element. The nonlocal mechanisms are fluid trapping (possible for both wetting and nonwetting fluids) and structure hysteresis arising from heterogeneity in the pore system. Our results arise from the analysis of imaging experiments in which water was successively imbibed into and drained from small samples of Bentheimer sandstone and unconsolidated grain packs. The experiment were conducted at both synchrotron and laboratory X-ray MCT facilities, with both imaging setups having sufficient resolution to show the distribution of the two fluid phases throughout the material while also capturing fluid menisci in individual pores. We apply a range of topological and geometric analyses to these images, most notably the calculation of Betti numbers, interfacial area and interfacial curvature, to quantify the differences in fluid configurations during imbibition and drainage. While our results suggest that geometric bistability may be the primary cause for hysteresis in these particular experiments, we discuss the significance of our results and suggest that far more work is needed before definitive conclusions can be drawn.

Sheppard, A.; Wildenschild, D.; Andersson, L.; Herring, A. L.

2013-12-01

267

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

268

Identical scaling behavior of saturated dynamic hysteresis in rhombohedral lead zirconate titanate bulk ceramics  

NASA Astrophysics Data System (ADS)

The scaling behaviors of dynamic hysteresis were investigated in serial rhombohedral Nb-doped Pb(Zr1-xTix)O3 (PZT) bulk ceramics as a function of frequency (f) and field amplitude (E0). Three distinct regions were plotted including linear loops, minor loops, and saturated loops with an increase of E0. When the external fields were over ˜1.5 times of coercive field (Ec), the scaling relations of saturated loops for these PZT ceramics could be expressed with an identical form as hysteresis area ?A? ? f 0.01E00.10, which indicated that similar ferroelectric systems with different compositions could display a uniform scaling law under high-E0 and low-f regions.

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

2013-12-01

269

Polarization-dependent asymmetric hysteresis behavior in ZnCrO layers  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

270

Re-examination of the Steinmetz law for unsymmetrical magnetic hysteresis loops  

NASA Astrophysics Data System (ADS)

We have re-examined the Steinmetz law for unsymmetrical flux-density(B)-field(H) loops in an arbitrary magnetized state for cold rolled steels from the viewpoint of magnetization mechanism. Under the criterion of B-H loops with |B|<˜ 1.1 T, a relation between the hysteresis loss and flux density change was found to fall almost the same curve as that for symmetrical loops obtained conventionally. In the intermediate B regime, the relation follows the usual Steinmetz law with a power-law exponent of 1.6, whose coefficient increases with defect density. These observations demonstrate that the hysteresis loss is only the function of the flux density change and the Steinmetz law always holds true in an arbitrary magnetized state if the pinning mechanism of irreversible Bloch wall motion prevails.

Kobayashi, Satoru; Ishibashi, Yusuke; Baba, Ryo

2013-03-01

271

Hysteresis loops and adiabatic Landau-Zener-Stückelberg transitions in the magnetic molecule {V6}.  

PubMed

We have observed hysteresis loops and abrupt magnetization steps in the magnetic molecule {V(6)}, where each molecule comprises a pair of identical spin triangles, in the temperature range 1-5 K for external magnetic fields B with sweep rates of several Tesla per millisecond executing a variety of closed cycles. The hysteresis loops are accurately reproduced using a generalization of the Bloch equation based on direct one-phonon transitions between the instantaneous Zeeman-split levels of the ground state (an S=1/2 doublet) of each spin triangle. The magnetization steps occur for B approximately 0, and they are explained in terms of adiabatic Landau-Zener-Stückelberg transitions between the lowest magnetic energy levels as modified by an intertriangle anisotropic exchange of order 0.4 K. PMID:15904102

Rousochatzakis, I; Ajiro, Y; Mitamura, H; Kögerler, P; Luban, M

2005-04-15

272

Hysteresis Loops and Adiabatic Landau-Zener-Stückelberg Transitions in the Magnetic Molecule {V6}  

NASA Astrophysics Data System (ADS)

We have observed hysteresis loops and abrupt magnetization steps in the magnetic molecule {V6}, where each molecule comprises a pair of identical spin triangles, in the temperature range 1 5 K for external magnetic fields B with sweep rates of several Tesla per millisecond executing a variety of closed cycles. The hysteresis loops are accurately reproduced using a generalization of the Bloch equation based on direct one-phonon transitions between the instantaneous Zeeman-split levels of the ground state (an S=1/2 doublet) of each spin triangle. The magnetization steps occur for B?0, and they are explained in terms of adiabatic Landau-Zener-Stückelberg transitions between the lowest magnetic energy levels as modified by an intertriangle anisotropic exchange of order 0.4 K.

Rousochatzakis, I.; Ajiro, Y.; Mitamura, H.; Kögerler, P.; Luban, M.

2005-04-01

273

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

274

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

275

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

276

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

277

Optical bistability and hysteresis of hybrid metal-semiconductor nano-dimer  

E-print Network

Optical response of an artificial composite nano-dimer comprising a semiconductor quantum dot and a metal nanosphere is analyzed theoretically. We show that internal degrees of freedom of the system can manifest bistability and optical hysteresis as functions of the incident field intensity. We argue that these effects can be observed for the real world systems, such as a CdSe quantum dot and an Au nanoparticle hybrids. These properties can be revealed by measuring the optical hysteresis of the Rayleigh scattering. We show also that the total dipole moment of the system can be switched abruptly between its two stable states by small changes in the excitation intensity. The latter promises various applications in the field of all-optical processing at nanoscale, the most underlying of them being the volatile optical memory.

Malyshev, A V

2011-01-01

278

Optical bistability and hysteresis of a hybrid metal-semiconductor nanodimer  

NASA Astrophysics Data System (ADS)

Optical response of an artificial composite nanodimer comprising a semiconductor quantum dot and a metal nanosphere is analyzed theoretically. We show that internal degrees of freedom of the system can manifest bistability and optical hysteresis as functions of the incident field intensity. We argue that these effects can be observed for real-world systems, such as a CdSe quantum dot and an Au nanoparticle hybrid. These properties can be revealed by measuring the optical hysteresis of Rayleigh scattering. We also show that the total dipole moment of the system can be switched abruptly between its two stable states by small changes in the excitation intensity. The latter promises various applications in the field of all-optical processing at the nanoscale, the most basic of them being the volatile optical memory.

Malyshev, A. V.; Malyshev, V. A.

2011-07-01

279

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

NASA Astrophysics Data System (ADS)

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

Zhang, Lefu; Takahashi, Seiki; Kamada, Yasuhiro; Kikuchi, Hiroaki; Mumtaz, Khalid; Ara, Katsuyuki; Sato, Masaya

2005-04-01

280

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

281

Soft x-ray magneto-optic Kerr rotation and element-specific hysteresis measurement  

SciTech Connect

Soft x-ray magneto-optic Kerr rotation has been measured using a continuously tunable multilayer linear polarizer in the beam reflected form samples in applied magnetic fields. Like magnetic circular dichroism, Kerr rotation in the soft x-ray can be element - specific and much larger than in the visible spectral range when the photon energy is tuned near atomic core resonances. Thus sensitive element-specific hysteresis measurements are possible with this technique. Examples showing large Kerr rotation from an Fe film and element-specific hysteresis loops of the Fe and Cr in an Fe/Cr multilayer demonstrate these new capabilities. Some consequences of the strong anomalous dispersion near the FeL{sub 2,3} edges to the Kerr rotation are discussed.

Kortright, J.B.; Rice, M.

1996-03-01

282

Influence of the magnetization damping on dynamic hysteresis loops in single domain particles  

NASA Astrophysics Data System (ADS)

This article reports on the influence of the magnetization damping on dynamic hysteresis loops in single-domain particles with uniaxial anisotropy. The approach is based on the Néel-Brown theory and the hierarchy of differential recurrence relations, which follow from averaging over the realizations of the stochastic Landau-Lifshitz equation. A new method of solution is proposed, where the resulting system of differential equations is solved directly using optimized algorithms to explore its sparsity. All parameters involved in uniaxial systems are treated in detail, with particular attention given to the frequency dependence. It is shown that in the ferromagnetic resonance region, novel phenomena are observed for even moderately low values of the damping. The hysteresis loops assume remarkably unusual shapes, which are also followed by a pronounced reduction of their heights. Also demonstrated is that these features remain for randomly oriented ensembles and, moreover, are approximately independent of temperature and particle size.

Landi, Gabriel T.

2012-02-01

283

Force control of a magnetorheological damper using an elementary hysteresis model-based feedforward neural network  

NASA Astrophysics Data System (ADS)

An inverse controller is proposed for a magnetorheological (MR) damper that consists of a hysteresis model and a voltage controller. The force characteristics of the MR damper caused by excitation signals are represented by a feedforward neural network (FNN) with an elementary hysteresis model (EHM). The voltage controller is constructed using another FNN to calculate a suitable input signal that will allow the MR damper to produce the desired damping force. The performance of the proposed EHM-based FNN controller is experimentally compared to existing control methodologies, such as clipped-optimal control, signum function control, conventional FNN, and recurrent neural network with displacement or velocity inputs. The results show that the proposed controller, which does not require force feedback to implement, provides excellent accuracy, fast response time, and lower energy consumption.

Ekkachai, Kittipong; Tungpimolrut, Kanokvate; Nilkhamhang, Itthisek

2013-11-01

284

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

285

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

286

Stress-induced magnetic hysteresis in amorphous microwires probed by microwave giant magnetoimpedance measurements  

NASA Astrophysics Data System (ADS)

We report the results of a detailed study of the effects of tensile and torsional stresses on the giant magnetoimpedance (GMI) characteristics of vanishing-magnetostrictive Co-rich microwires at microwave frequency. A complex stress-induced hysteresis behaviour is identified in the GMI response in the presence of tensile and torsional stresses. It is also revealed that there exists a competition between these two kinds of stresses on the critical field via the interactions with the intrinsic anisotropy. An "enhanced core-shell" model is proposed here to resolve the physical origin of the low-field hysteresis and the dependence of induced anisotropy field on the applied tensile and/or torsional stress. Our results are of both technical importance to the design of non-contact stress sensors exploiting the GMI of microwires and fundamental significance to the understanding of the microwave GMI characteristics of soft magnetic microwires in the presence of external stresses.

Popov, V. V.; Berzhansky, V. N.; Gomonay, H. V.; Qin, F. X.

2013-05-01

287

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

SciTech Connect

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

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

1988-11-15

288

Iterative control approach to compensate for the hysteresis and the vibrational dynamics effects of piezo actuators  

Microsoft Academic Search

In this article, an inversion-based iterative control (IIC) approach is used to compensate for both the hysteresis and the vibrational dynamics effects of piezo actuators during high-speed, large-range tracking. We use the Hammerstein model to capture the piezo's input-output behavior and to show the convergence of the iterative control algorithm. The IIC approach is illustrated by applying it to a

Ying Wu; Qingze Zou

2006-01-01

289

Hysteresis-free electro-optical switching in conductive ferroelectric liquid crystals: experiments and modelling  

Microsoft Academic Search

The hysteresis-free electro-optical switching, or so-called V-shaped, regime has been studied in a commercial ferroelectric liquid crystal (FLC) mixture having a smectic C* phase with a very small value of spontaneous polarization. The FLC was introduced into commercial EHC cells with thin aligning layers. In such cells V-shaped switching could be observed only at very low frequencies, less than 1?Hz.

S. P. Palto; F. V. Podgornov; H. Moritake; W. Haase

2004-01-01

290

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

291

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

292

Memory-Efficient Architecture for Hysteresis Thresholding and Object Feature Extraction  

Microsoft Academic Search

Hysteresis thresholding is a method that offers en- hanced object detection. Due to its recursive nature, it is time consuming and requires a lot of memory resources. This makes it avoided in streaming processors with limited memory. We propose two versions of a memory-efficient and fast architecture for hys- teresis thresholding: a high-accuracy pixel-based architecture and a faster block-based one

Mayssaa A. Najjar; Swetha Karlapudi; Magdy A. Bayoumi

2011-01-01

293

Output zeroing of MIMO plants in the presence of actuator and sensor uncertain hysteresis nonlinearities  

Microsoft Academic Search

This note tackles the output zeroing problem of a square multiple-input-multiple-output plant containing uncertain nonsmooth hysteresis-like nonlinearities in actuator and sensor devices simultaneously. To this purpose, a robust sliding mode controller, based on the output of a reduced order observer, has been designed using it, such control law ensuring both the asymptotical zeroing of the sensing nonlinearities output and the

G. Parlangeli; M. L. Corradini

2005-01-01

294

Hysteresis and negative differential resistance of the current-voltage characteristic of a water bridge  

NASA Astrophysics Data System (ADS)

It is found experimentally that the properties of nanoporous ion-exchange membranes (hysteresis of the current-voltage characteristic in the solution and negative differential resistance), which have been discussed in recent years, are not associated with the properties of the membrane. It is shown that these effects are also observed in a floating water bridge and in water-filled tubes and are apparently determined by the geometrical shape of the liquid conductor. The observed effects are explained qualitatively.

Oshurko, V. B.; Fedorov, A. N.; Ropyanoi, A. A.; Fedosov, M. V.

2014-06-01

295

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

296

Hysteresis in elastic behavior: The connection between low-frequency response and acoustic properties of rocks  

Microsoft Academic Search

The strain response of rock to quasistatic stress cycles (e.g., 10⁻³ Hz) is highly nonlinear, hysteretic, and displays discrete memory. Rocks also display unusual nonlinear behavior in acoustic wave experiments (e.g., 10⁴ Hz). Nonlinearity and hysteresis are prominent features in elastic measurements on rocks. This observation is the key to making the connection between low-frequency (quasistatic) and high-frequency (acoustic) measurements,

Katherine R. McCall; R. A. Guyer; L. Zhu

1995-01-01

297

Quantification of hysteresis and nonlinear effects on the frequency response of ferroelectric and ferromagnetic materials  

Microsoft Academic Search

Ferroelectric (e.g., PZT and PMN) and ferromagnetic (e.g., Terfenol-D) materials exhibit high energy densities, broadband drive capabilities, and the capacity for both actuating and sensing. This makes them attractive as compact transducers for a wide range of applications. However, the materials also exhibit hysteresis and constitutive nonlinearities, at all drive levels, that must be quantified and accommodated to achieve stringent

M. Stuebner; J. Atulasimha; R. C. Smith

2009-01-01

298

Hysteresis and negative differential resistance of the I-V characteristic of a water bridge  

NASA Astrophysics Data System (ADS)

It is experimentally demonstrated that the recently discussed properties of the nanopore ion-exchange membranes (hysteresis of the I-V characteristic in solution and negative differential resistance) are not related to the membrane structure. The same effects are observed in a water bridge and tubes filled with water and may be related to the geometrical shape of the liquid conductor. The experimental effects are qualitatively interpreted.

Oshurko, V. B.; Fedorov, A. N.; Ropyanoi, A. A.; Fedosov, M. V.

2014-08-01

299

Hysteresis-Current-Controlled Buck Converter Suitable for Li-Ion Battery Charger  

Microsoft Academic Search

A new hysteresis-current-controlled (HCC) buck converter suitable for Li-ion battery charger is presented in this paper. The technique adopted in this charger is constant current\\/constant voltage dual mode, which is decided by the value of internal resistance of Li-ion battery. This technique will degrade the damage of Li-ion battery and improve the power efficiency of charger. The Li-ion battery charger

Fong-Cheng Yang; Chih-Chiang Chen; Jiann-Jong Chen; Yuh-Shyan Hwang; Wen-Ta Lee

2006-01-01

300

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

301

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

302

Purification and characterization of a thermal hysteresis protein from a plant, the bittersweet nightshade Solanum dulcamara.  

PubMed

Thermal hysteresis proteins (THPs), which depress the freezing point of water below the melting point (producing a characteristic thermal hysteresis), are well known for their antifreeze activity in both fish and terrestrial arthropods, but have only recently been identified in plants. This study describes the purification of a THP from winter-collected bittersweet nightshade, Solanum dulcamara, using ion exchange and preparative 'free flow' isoelectric focusing. The THP has a molecular mass of 67 kDa (considerably larger than those of animal THPs), and an unusually high glycine component (23.7 mol%). Treatments of the THP with periodate or borate caused inactivation, suggesting the presence of carbohydrate. More specific treatments directed at galactose (beta-galactosidase or Abrus precatorius lectin) also resulted in inactivation, indicating that galactose is present. A thermal hysteresis activity versus THP concentration curve showed that the specific activity of the S. dulcamara THP is lower than that of any known animal THP. The functional significance of this low activity is discussed. PMID:8186242

Duman, J G

1994-05-18

303

Hysteresis properties of ordinary chondrites and implications for their thermal history  

NASA Astrophysics Data System (ADS)

We present a large dataset of magnetic hysteresis properties of ordinary chondrite falls. We show that hysteresis properties are distinctive of individual meteorites while homogeneous among meteorite subsamples. Except for the most primitive chondrites, these properties can be explained by a mixture of multidomain kamacite and tetrataenite (both in the cloudy zone and as larger grains in plessite and in the rim of zoned taenite). Kamacite dominates the induced magnetism whereas tetrataenite dominates the remanent magnetism, in agreement with previous microscopic magnetic observations. Type 5 and 6 chondrites have higher tetrataenite content than type 4 chondrites, suggesting they have lower cooling rates at least in the 650-450 °C interval, consistent with an onion-shell model. In equilibrated chondrites, shock-related transient heating events above ~500 °C result in the disordering of tetrataenite and associated drastic change in magnetic properties. As a good indicator of the amount of tetrataenite, hysteresis properties are a very sensitive proxy of the thermal history of ordinary chondrites, revealing low cooling rates during thermal metamorphism, and high cooling rates following shock reheating or excavation after thermal metamorphism.

Gattacceca, J.; Suavet, C. R.; Rochette, P.; Weiss, B. P.; Winklhofer, M.; Uehara, M.; Friedrich, J. M.

2013-12-01

304

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

305

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

306

Hysteresis Modeling of Magnetic Shape Memory Alloy Actuator Based on Krasnosel'skii-Pokrovskii Model  

PubMed Central

As a new type of intelligent material, magnetically shape memory alloy (MSMA) has a good performance in its applications in the actuator manufacturing. Compared with traditional actuators, MSMA actuator has the advantages as fast response and large deformation; however, the hysteresis nonlinearity of the MSMA actuator restricts its further improving of control precision. In this paper, an improved Krasnosel'skii-Pokrovskii (KP) model is used to establish the hysteresis model of MSMA actuator. To identify the weighting parameters of the KP operators, an improved gradient correction algorithm and a variable step-size recursive least square estimation algorithm are proposed in this paper. In order to demonstrate the validity of the proposed modeling approach, simulation experiments are performed, simulations with improved gradient correction algorithm and variable step-size recursive least square estimation algorithm are studied, respectively. Simulation results of both identification algorithms demonstrate that the proposed modeling approach in this paper can establish an effective and accurate hysteresis model for MSMA actuator, and it provides a foundation for improving the control precision of MSMA actuator. PMID:23737730

Wang, Shoubin; Gao, Wei

2013-01-01

307

Magneto-optic waveguide hysteresis loops of ``planar'' magnetic garnet films  

NASA Astrophysics Data System (ADS)

Epitaxial films of modified yttrium iron garnet which are used as optical waveguides for magneto-optic devices have nominally planar anisotropy so that their magnetization can be aligned by small in-plane fields. Films grown on (111) substrates usually have some residual cubic anisotropy that is difficult to measure in the active layer of the double- or triple-layer films used in single-mode waveguides. A new method to determine the magnetic properties of the optically active layer itself has been developed. It is based on magneto-optical hysteresis loops in which the Faraday rotation of the waveguided light is plotted against one component of a rotating in-plane magnetic field. Steps in these hysteresis loops are directly related to the sixfold symmetry of the magnetocrystalline anisotropy of these films. The influence of linear birefringence on the measured Faraday rotation, the magnetostrictive effects associated with the pressure of the prism used for optical coupling into the waveguide, and the advantages of end-fire coupling are discussed. These hysteresis loops are being used in the design of materials for magneto-optic isolators and other waveguide devices.

McGlashan-Powell, M.; Wolfe, R.; Dillon, J. F., Jr.; Fratello, V. J.

1989-10-01

308

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

309

Novel Current Error Space Phasor Based Hysteresis Controller Using Parabolic Bands for Control of Switching Frequency Variations  

Microsoft Academic Search

A current error space phasor based simple hysteresis controller is proposed in this paper to control the switching frequency variation in two-level pulsewidth-modulation (PWM) inverter-fed induction motor (IM) drives. A parabolic boundary for the current error space phasor is suggested for the first time to obtain the switching frequency spectrum for output voltage with hysteresis controller similar to the constant

P. N. Tekwani; R. S. Kanchan; K. Gopakumar

2007-01-01

310

Evaluation of thermal ageing conditions in 17-4 PH stainless steel by Fourier descriptor analysis of magnetic hysteresis loops  

Microsoft Academic Search

Fourier descriptor analysis of magnetic hysteresis loops has been used to assess the conditions of isothermal and isochronal ageing in quench-aged precipitation hardening 17-4 PH stainless steel. The Fourier descriptors (i.e. sine harmonic coefficients in the Fourier series expansion of the magnetic flux density as a function of current arc length value of the ascending branch of hysteresis loop) have

N. I. Shakshin; G. I. Deordiev; V. E. Scherbinin; V. Moorthy; T. Jayakumar; D. K. Bhattacharya; P. Kalyanasundaram; Baldev Raj

1996-01-01

311

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

312

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

313

Wideband and hysteresis-free regulation of piezoelectric actuator based on induced current for high-speed scanning probe microscopy  

Microsoft Academic Search

A novel closed-loop regulation of a piezoelectric actuator is presented to implement wideband and hysteresis-free motion required for high-speed operation of scanning probe microscopy. Velocity of the actuator’s displacement detected via the induced current and its integration giving the displacement were used to actively compensate the resonances and hysteresis. The validity of the idea was demonstrated using a prototype circuit

Masami Kageshima; Shinsuke Togo; Yan Jun Li; Yoshitaka Naitoh; Yasuhiro Sugawara

2006-01-01

314

Metal phases in ordinary chondrites: Magnetic hysteresis properties and implications for thermal history  

NASA Astrophysics Data System (ADS)

Magnetic properties are sensitive proxies to characterize FeNi metal phases in meteorites. We present a data set of magnetic hysteresis properties of 91 ordinary chondrite falls. We show that hysteresis properties are distinctive of individual meteorites while homogeneous among meteorite subsamples. Except for the most primitive chondrites, these properties can be explained by a mixture of multidomain kamacite that dominates the induced magnetism and tetrataenite (both in the cloudy zone as single-domain grains, and as larger multidomain grains in plessite and in the rim of zoned taenite) dominates the remanent magnetism, in agreement with previous microscopic magnetic observations. The bulk metal contents derived from magnetic measurements are in agreement with those estimated previously from chemical analyses. We evidence a decreasing metal content with increasing petrologic type in ordinary chondrites, compatible with oxidation of metal during thermal metamorphism. Types 5 and 6 ordinary chondrites have higher tetrataenite content than type 4 chondrites. This is compatible with lower cooling rates in the 650-450 °C interval for higher petrographic types (consistent with an onion-shell model), but is more likely the result of the oxidation of ordinary chondrites with increasing metamorphism. In equilibrated chondrites, shock-related transient heating events above approximately 500 °C result in the disordering of tetrataenite and associated drastic change in magnetic properties. As a good indicator of the amount of tetrataenite, hysteresis properties are a very sensitive proxy of the thermal history of ordinary chondrites, revealing low cooling rates during thermal metamorphism and high cooling rates (e.g., following shock reheating or excavation after thermal metamorphism). Our data strengthen the view that the poor magnetic recording properties of multidomain kamacite and the secondary origin of tetrataenite make equilibrated ordinary chondrites challenging targets for paleomagnetic study.

Gattacceca, J.; Suavet, C.; Rochette, P.; Weiss, B. P.; Winklhofer, M.; Uehara, M.; Friedrich, Jon M.

2014-04-01

315

Hysteresis in suspended sediment to turbidity relations due to changing particle size distributions  

USGS Publications Warehouse

Turbidity (T) is the most ubiquitous of surrogate technologies used to estimate suspended-sediment concentration (SSC). The effects of sediment size on turbidity are well documented; however, effects from changes in particle size distributions (PSD) are rarely evaluated. Hysteresis in relations of SSC-to-turbidity (SSC~T) for single stormflow events was observed and quantified for a data set of 195 concurrent measurements of SSC, turbidity, discharge, velocity, and volumetric PSD collected during five stormflows in 2009–2010 on Yellow River at Gees Mill Road in metropolitan Atlanta, Georgia. Regressions of SSC-normalized turbidity (T/SSC) on concurrently measured PSD percentiles show an inverse, exponential influence of particle size on turbidity that is not constant across the size range of the PSD. The majority of the influence of PSD on T/SSC is from particles of fine-silt and smaller sizes (finer than 16 microns). This study shows that small changes in the often assumed stability of the PSD are significant to SSC~T relations. Changes of only 5 microns in the fine silt and smaller size fractions of suspended sediment PSD can produce hysteresis in the SSC~T rating that can increase error and produce bias. Observed SSC~T hysteresis may be an indicator of changes in sediment properties during stormflows and of potential changes in sediment sources. Trends in the PSD time series indicate that sediment transport is capacity-limited for sand-sized sediment in the channel and supply-limited for fine silt and smaller sediment from the hillslope.

Landers, Mark N.; Sturm, Terry W.

2013-01-01

316

Estimating hysteresis in the soil water retention function from cone permeameter experiments  

NASA Astrophysics Data System (ADS)

Data obtained from modified cone penetrometer experiments were used to estimate the hysteretic soil hydraulic properties with a parameter estimation technique which combined a numerical solution of the Richards equation with Marquardt-Levenberg optimization. The modified cone penetrometer was designed to inject water into a soil through a cylindrical screen, measure the infiltration rate with time, and track the movement of the wetting front using two tensiometer rings positioned above the screen. After reaching relatively stable tensiometer readings during the experiments, the source of water was cut off and pressure head readings measured while water in the soil profile redistributed. Cumulative inflow and pressure head readings for two experiments with different supply pressures were analyzed to obtain estimates of the soil water retention and hydraulic conductivity functions. Analysis of flow responses obtained during the infiltration period, and of those obtained during the combined infiltration and redistribution phases, demonstrated the importance of hysteresis of the soil hydraulic functions. We found that the redistribution phase could not be described accurately when hysteresis was neglected. Hysteresis in the soil hydraulic functions was modeled using a relatively simple empirical model in which wetting scanning curves are scaled from the main wetting curve and drying scanning curves are scaled from the main drying curve. This model was deemed adequate for our examples. Optimization results for various combinations of unknown soil hydraulic parameters were compared to results of standard laboratory and in situ methods. Estimates of the saturated hydraulic conductivity were well within the range of in situ measurements. The estimated main hysteretic loops of the soil water retention curve were for the most part situated between the wetting and drying curves obtained with standard methods.

Šim?nek, Ji?í; Kodešová, Radka; Gribb, Molly M.; van Genuchten, Martinus T.

317

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

SciTech Connect

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

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

1992-01-01

318

Hysteresis, thermomagnetic, and low-temperature magnetic properties of Southwestern U.S. obsidians  

NASA Astrophysics Data System (ADS)

Geochemical signatures of Southwestern U.S. obsidians have been intensively studied, in part to use as a provenance method for archaeological obsidians (Shackley, 2005). We reported (Sternberg et al. 2010) examined magnetic properties of 50 unoriented samples from 10 geologic obsidian sources in Arizona, Nevada, and New Mexico; here we provide additional results measured at the Institute for Rock magnetism. Room-temperature hysteresis curves were measured using a vibrating sample magnetometer on 58 specimens from all 50 samples. The Quantum Designs Magnetic Properties Measurement System was used to measure low temperature cycling of the natural remanence and/or of a room-temperature saturation isothermal remanence for 10 specimens, and frequency dependence of susceptibility for 7 specimens. A Princeton VSM was used to measure hysteresis curves and thermomagnetic curves for 19 specimens from 17 samples. Eleven of the thermomagnetic curves show Curie temperatures close to that for magnetite, and most of them are almost perfectly reversible. Many of the specimens also show a less well-defined Curie point around 150-200°C; for a few specimens the thermomagnetic behavior is dominated by paramagnetic iron and no ferromagnetic phases can be identified. The low-temperature remanence and susceptibility measurements show the magnetite Verwey transition in almost all specimens, and a significant superparamagnetic presence in only a few cases. Hysteresis parameters plot mainly in the lower half of the PSD domain on a Day plot, and saturation magnetization values indicate magnetite concentrations of about 0.2% to 0.5% for most specimens. The coercivity of remanence decreased considerably for one specimen after surface cleaning, although for 5 other comparisons there was no change.

Sternberg, R. S.; Jackson, M. J.; Shackley, M. S.

2011-12-01

319

Mesoscopic resistive switch: non-volatility, hysteresis and negative differential resistance  

NASA Astrophysics Data System (ADS)

We show how a simple model nanoswitch can perform as a memory resistor. Its resistance is determined by electron tunneling through a nanoparticle diffusing around one or more potential minima located between the electrodes in the presence of Joule's heat dissipation. In the case of a single potential minimum, we observe hysteresis of the resistance at finite applied currents and negative differential resistance. For two (or more) minima the switching mechanism is non-volatile, meaning that the memristor can switch to a resistive state of choice and stay there. Moreover, the noise spectra of the switch exhibit 1/ f 2 ? 1/ f crossover, in agreement with recent experimental results.

Savel'ev, Sergey E.; Marchesoni, Fabio; Bratkovsky, Alexander M.

2013-12-01

320

Stability of dithered non-linear systems with backlash or hysteresis  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

321

Gas flow across a wet screen - Analogy to a relief valve with hysteresis  

NASA Technical Reports Server (NTRS)

The flow of gas through a wet fine-mesh screen is analyzed in terms of the capillary forces of the liquid wetting the screen and the pressure difference across the screen thickness driving the gas flow. Several different types of time-dependent flow are shown to be possible. The most interesting type is one in which the pressure difference opens small channels in the liquid, which are then closed rapidly by the wetting action of the liquid. The opening and closing exhibit hysteresis, and the flow is highly oscillatory.

Nachman, A.; Dodge, F. T.

1983-01-01

322

Hysteresis curves for ferroelectric crystals in a varying external field. Relaxation model  

NASA Astrophysics Data System (ADS)

We propose a description of switching in ferroelectric crystals using the equations of relaxation processes taking into account the action of a varying external electric field. Exact analytic solutions to these equations are obtained for an arbitrary dependence of the relaxation time on the external field and an arbitrary time dependence of the external field. The resultant solution forms the basis of numerical analysis of coupling between the frequency of the sinusoidal external field and the shape of the hysteresis curves. The results of calculations are in qualitative agreement with experimental data.

Zakharov, A. Yu.; Bichurin, M. I.; Yan, Y.; Priya, S.

2014-08-01

323

Engineering double-shifted hysteresis loops in Co/IrMn/Cu/Co films  

NASA Astrophysics Data System (ADS)

Co(3 nm)/IrMn(15 nm)/Cu(dCu)/Co(7 nm) films were subjected to magnetic annealing where its temperature and duration as well as the direction and amplitude of the applied field were varied. We demonstrate that the exchange-bias field magnitude and sign of the subloop of the bottom-pinned Co layer can be tailored in a controlled manner allowing the whole hysteresis loop to be tuned from a double negatively/negatively shifted to a double negatively/positively shifted with the shifts of the subloops in antiphase.

Cichelero, R.; Pereira, L. G.; Dias, T.; Schmidt, J. E.; Deranlot, C.; Petroff, F.; Geshev, J.

2009-09-01

324

Observation of acousto-elastic hysteresis in kinking nonlinear elastic solids  

NASA Astrophysics Data System (ADS)

Using bulk acoustic waves we studied the nonlinear mechanical properties and hysteresis of the acousto-elastic effect in kinking nonlinear elastic, KNE, solids. The experiments reviewed here present direct observation of nonlinear hysteretic scattering and attenuation of ultrasonic waves in Ti3SiC2 and Ti3AlC2, representatives of KNE solids, as a function of quasi-static cyclic compressive stresses. We attribute this dynamic behavior to the interaction of the acoustic waves with dislocation in incipient kink bands. The relevance of these findings to possible sensor applications of hysteretic KNE solids is briefly discussed.

Finkel, Peter; Zhou, Aiguo; Barsoum, Michel

2009-03-01

325

On the Observation of Acousto-Elastic Hysteresis in Kinking Nonlinear Elastic Solids  

NASA Astrophysics Data System (ADS)

Using bulk acoustic waves we studied the nonlinear mechanical properties and hysteresis of the acousto-elastic effect in kinking nonlinear elastic, KNE, solids. The experiments reviewed here present direct observation of nonlinear hysteretic scattering and attenuation of ultrasonic waves in Ti3SiC2 and Ti3AlC2, representatives of KNE solids, as a function of quasi-static cyclic compressive stresses. We attribute this dynamic behavior to the interaction of the acoustic waves with dislocation in incipient kink bands. The relevance of these findings to possible sensor applications of hysteretic KNE solids is briefly discussed.

Finkel, P.; Zhou, A. G.; Basu, S.; Yeheskel, O.; Barsoum, M. W.

2009-03-01

326

Well-posedness for a class of biological diffusion models with hysteresis effect  

NASA Astrophysics Data System (ADS)

This paper is concerned with a class of biological models which consist of nonlinear diffusion equations and a hysteresis operator describing the relationship between some variables of the equations. The existence of solutions to the analogous problem was ever considered by Aiki and Minchev (SIAM J Math Anal 36:2020-2032, 2005) under some assumptions including the global Lipschitz continuity of reaction terms. We show the existence of nonnegative solutions to the problem under consideration using the approximation method when the reaction terms are locally Lipschitz continuous. Moreover, we discuss the continuous dependence of solutions on initial data.

Zheng, Jiashan; Wang, Yifu

2014-05-01

327

Droplets on Inclined Plates: Local and Global Hysteresis of Pinned Capillary Surfaces  

NASA Astrophysics Data System (ADS)

Local contact line pinning prevents droplets from rearranging to minimal global energy, and models for droplets without pinning cannot predict their shape. We show that experiments are much better described by a theory, developed herein, that does account for the constrained contact line motion, using as an example droplets on tilted plates. We map out their shapes in suitable phase spaces. For 2D droplets, the critical point of maximum tilt depends on the hysteresis range and Bond number. In 3D, it also depends on the initial width, highlighting the importance of the deposition history.

Musterd, Michiel; van Steijn, Volkert; Kleijn, Chris R.; Kreutzer, Michiel T.

2014-08-01

328

Hysteresis and memory factor of the Kerr effect in blue phases  

NASA Astrophysics Data System (ADS)

The performance of a polymer-stabilized blue phase system based on a nematic host with large dielectric anisotropy and a chiral dopant with high helical twisting power is investigated and the influence of the reactive monomer composition on the electro-optic characteristics is studied. Field-induced birefringence with a Kerr coefficient greater than 1 nm V-2 can be achieved in a large temperature range from well below 20 °C to above 55 °C. The disturbing influences of electro-optic hysteresis and memory effects can be reduced by diligent choice of the composition and appropriate electric addressing.

Nordendorf, Gaby; Lorenz, Alexander; Hoischen, Andreas; Schmidtke, Jürgen; Kitzerow, Heinz; Wilkes, David; Wittek, Michael

2013-11-01

329

Turbidity-based sediment monitoring in northern Thailand: Hysteresis, variability, and uncertainty  

NASA Astrophysics Data System (ADS)

Annual total suspended solid (TSS) loads in the Mae Sa Catchment in northern Thailand, determined with an automated, turbidity-based monitoring approach, were approximately 62,000, 33,000, and 14,000 Mg during the three years of observation. These loads were equivalent to basin yields of 839 (603-1170), 445 (217-462), and 192 (108-222) Mg km-2 for the 74.16-km2 catchment during 2006, 2007, and 2008, respectively. The yearly uncertainty ranges indicate our loads may be underestimated by 38-43% or overestimated by 28-33%. In determining the annual loads, discharge (Q) and turbidity (T) values were compared against 333 hand-sampled total suspended solid concentrations (TSS) measured during 18 runoff events and other flow conditions across the three-year period. Annual rainfall varied from 1632 to 1934 mm; and catchment runoff coefficients (annual runoff/annual rainfall) ranged from 0.25 to 0.41. Measured TSS ranged from 8 to 15,900 mg l-1; the low value was associated with dry-season base flow; the latter, a wet-season storm. Storm size and location played an important role in producing clockwise, anticlockwise, and complex hysteresis in the Q-TSS relationship. Turbidity alone was a good estimator for turbidity ranges of roughly 10-2800 NTU (or concentrations approximately 25-4000 mg l-1). However, owing to hysteresis and high sediment concentrations that surpass the detection limits of the turbidity sensor during many annual storms, TSS was estimated best using a complex multiple regression equation based on high/low ranges of turbidity and Q as independent variables. Turbidity was not a good predictor of TSS fractions >2000 ?m. Hysteresis in the monthly Q-TSS relationship was generally clockwise over the course of the monsoon season, but infrequent large dry-season storms disrupted the pattern in some years. The large decrease in annual loads during the study was believed to be related to depletion of fine sediment delivered to the stream by several landslides occurring the year prior to the study. The study indicated the importance of monitoring Q and turbidity at fine resolutions (e.g., sub-hourly) to capture the TSS dynamics and to make accurate load estimations in this flashy headwater stream where hysteresis in the Q-TSS signature varied at several time scales.

Ziegler, Alan D.; Benner, Shawn G.; Tantasirin, Chatchai; Wood, Spencer H.; Sutherland, Ross A.; Sidle, Roy C.; Jachowski, Nicholas; Nullet, Mike A.; Xi, Lu Xi; Snidvongs, Anond; Giambelluca, Thomas W.; Fox, Jefferson M.

2014-11-01

330

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

SciTech Connect

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

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

2014-08-15

331

Magnetic hysteresis classification of the lunar surface and the interpretation of permanent remanence in lunar surface samples  

NASA Technical Reports Server (NTRS)

A magnetic hysteresis classification of the lunar surface is presented. It was found that there is a distinct correlation between natural remanence (NRM), saturation magnetization, and the hysteresis ratios for the rock samples. The hysteresis classification is able to explain some aspects of time dependent magnetization in the lunar samples and relates the initial susceptibility to NRM, viscous remanence, and to other aspects of magnetization in lunar samples. It is also considered that since up to 60% of the iron in the lunar soil may be super paramagnetic at 400 K, and only 10% at 100 K, the 50% which becomes ferromagnetic over the cycle has the characteristics of thermoremanence and may provide for an enhancement in measurable field on the dark side during a subsatellite magnetometer circuit.

Wasilewski, P.

1972-01-01

332

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

333

The Effect of Tensile Hysteresis and Contact Resistance on the Performance of Strain-Resistant Elastic-Conductive Webbing  

PubMed Central

To use e-textiles as a strain-resistance sensor they need to be both elastic and conductive. Three kinds of elastic-conductive webbings, including flat, tubular, and belt webbings, made of Lycra fiber and carbon coated polyamide fiber, were used in this study. The strain-resistance properties of the webbings were evaluated in stretch-recovery tests and measured within 30% strain. It was found that tensile hysteresis and contact resistance significantly influence the tensile elasticity and the resistance sensitivity of the webbings. The results showed that the webbing structure definitely contributes to the tensile hysteresis and contact resistance. The smaller the friction is among the yarns in the belt webbing, the smaller the tensile hysteresis loss. However the close proximity of the conductive yarns in flat and tubular webbings results in a lower contact resistance. PMID:22319376

Shyr, Tien-Wei; Shie, Jing-Wen; Jhuang, Yan-Er

2011-01-01

334

Efficient modeling of vector hysteresis using a novel Hopfield neural network implementation of Stoner–Wohlfarth-like operators  

PubMed Central

Incorporation of hysteresis models in electromagnetic analysis approaches is indispensable to accurate field computation in complex magnetic media. Throughout those computations, vector nature and computational efficiency of such models become especially crucial when sophisticated geometries requiring massive sub-region discretization are involved. Recently, an efficient vector Preisach-type hysteresis model constructed from only two scalar models having orthogonally coupled elementary operators has been proposed. This paper presents a novel Hopfield neural network approach for the implementation of Stoner–Wohlfarth-like operators that could lead to a significant enhancement in the computational efficiency of the aforementioned model. Advantages of this approach stem from the non-rectangular nature of these operators that substantially minimizes the number of operators needed to achieve an accurate vector hysteresis model. Details of the proposed approach, its identification and experimental testing are presented in the paper.

Adly, Amr A.; Abd-El-Hafiz, Salwa K.

2012-01-01

335

Neurons with hysteresis from a network that can learn without any changes in synaptic connection strengths  

SciTech Connect

A neural network concept derived from an analogy between the immune system and the central nervous system is outlined. The theory is based on a neuron that is slightly more complicated than the conventional McCullogh-Pitts type of neuron, in that is exhibits hysteresis at the single cell level. This added complication is compensated by the fact that a network of such neurons is able to learn without the necessity for any changes in synaptic connection strengths. The learning occurs as a neural consequence of interactions between the network and its environment, with environmental stimuli moving the system around in an N-dimensional phase space, until a point in phase space is reached such that the system's responses are appropriate for dealing with the stimuli. Due to the hysteresis associated with each neuron, the system tends to stay in the region of phase space where it is located. The theory includes a role for sleep in learning. 18 refs., 2 figs.

Hoffmann, G.W.; Benson, M.W.

1986-01-01

336

The Identification and Suppression of Defects Responsible for Electrical Hysteresis in Metal-Nitride-Silicon Capacitors  

NASA Astrophysics Data System (ADS)

An attempt was made to correlate the hysteresis in high frequency capacitance-voltage (C-V) measurements on metal-nitride-silicon (MNS) capacitors and spin density measured by electron spin resonance (ESR) spectrometry on a series of silicon-rich and nitrogen-rich silicon nitride films deposited by plasma enhanced chemical vapor deposition (PECVD). We found that the hysteresis \\varDelta VH in the C-V characteristics can be divided into \\varDelta V+, which corresponds to negative charge trapping, and \\varDelta V-, which corresponds to positive charge trapping. A one-to-one correlation was found between \\varDelta V+ and the spin density attributed to the silicon dangling bond. However, \\varDelta V- was nearly constant even though the spin density changed by two orders of magnitude. Nevertheless, \\varDelta V- was found to be significantly reduced by an ammonia plasma treatment of the silicon substrate before the silicon nitride deposition. These observations support the hypothesis that besides the silicon dangling bond, which can be suppressed by using nitrogen-rich films instead of silicon-rich films, there is another important type of defect probably at the nitride-silicon interface, which can be suppressed by an appropriate ammonia plasma treatment.

Lau, W. S.

1990-05-01

337

Saturation and hysteresis effects in ionospheric modification experiments observed by the CUTLASS and EISCAT radars  

NASA Astrophysics Data System (ADS)

The results of high latitude ionospheric modification experiments utilising the EISCAT heating facility at Tromsø are presented. As a result of the interaction between the high power pump waves and upper hybrid waves in the ionosphere, field-aligned electron density irregularities are artificially excited. Observations of these structures with the CUTLASS coherent HF radars and the EISCAT incoherent UHF radar exhibit hysteresis effects as the heater output power is varied. These are explained in terms of the two-stage mechanism which leads to the growth of the irregularities. Experiments which involve preconditioning of the ionosphere also indicate that hysteresis could be exploited to maximise the intensity of the field-aligned irregularities, especially where the available heater power is limited.

In addition, the saturation of the irregularity amplitude is considered. Although, the rate of irregularity growth becomes less rapid at high heater powers it does not seem to fully saturate, indicating that the amplification would continue beyond the capabilities of the Tromsø heater - currently the most powerful of its kind. It is shown that the CUTLASS radars are sensitive to irregularities produced by very low heater powers (effective radiated powers <4 MW). This fact is discussed from the perspective of a new heating facility, SPEAR, located on Spitzbergen and capable of transmitting high frequency radio waves with an effective radiated power ~10% of that of the Tromsø heater (28MW).

Wright, D. M.; Davies, J. A.; Yeoman, T. K.; Robinson, T. R.; Shergill, H.

2006-03-01

338

Local hysteresis loops measurements on irradiated FeSiB patterned dots by magnetic force microscopy  

NASA Astrophysics Data System (ADS)

Magnetic Force Microscopy (MFM) has been exploited to develop a technique capable of investigating the field-dependent magnetisation reversal processes in patterned systems, allowing the full reconstruction of a local hysteresis loop. Fe-Si-B dots with a lateral size of 6 ?m and a thickness of 250 nm have been prepared by sputtering and optical lithography. In the as-prepared state, the dots are characterised by a dense stripe domain configuration, clearly visible at the MFM. Subsequently, the dots have been thinned by means of exposition to a focussed ion beam, consisting of Ga+ ions having an energy of 30 keV. The local hysteresis loops have been measured by means of the MFM-derived technique. The progressive thinning of the dots results in the disappearance of the perpendicular anisotropy responsible for the dense stripe domain configuration, with the dominance of the shape anisotropy for thickness values below ?70 nm. The results are consistent with the spin reorientation transition effect studied on similar systems in the form of continuous thin films.

Coïsson, M.; Barrera, G.; Celegato, F.; Enrico, E.; Olivetti, E. S.; Tiberto, P.; Vinai, F.

2015-01-01

339

Motion of an isolated liquid plug inside a capillary tube: effect of contact angle hysteresis  

NASA Astrophysics Data System (ADS)

Dynamics of a single, small and isolated partially wetting liquid plug (of known length L and wettability), placed at rest inside a long, dry, circular capillary tube ( D = 1.5 mm), and subsequently quasi-statically pushed from one end by applying air pressure, the other end being kept exposed to atmosphere, are reported. The air pressure first overcomes the `static' friction manifested by the three-phase contact line at the advancing and receding menisci, and then, the plug motion gets initiated, eventually leading to a terminal velocity (Ca ~ 2.8 × 10-5), when pressure force balances net frictional resistance due to viscous and surface forces. It is seen that, under steady motion, the curvature profiles of the advancing and receding menisci of liquid plug, respectively, remain the same, independent of the plug length. Steady-state pressure drop is dominated by the contribution due to contact angle hysteresis, which is also independent of the plug length. Increasing the system wettability drastically decreased the contact angle hysteresis and the associated net pressure drop.

Srinivasan, Vyas; Khandekar, Sameer; Bouamrane, Nathan; Lefevre, Frederic; Bonjour, Jocelyn

2015-01-01

340

Observation of electrical switching, reverse rectification and hysteresis in nanostructured organic-organic heterojunction.  

PubMed

Nanostructured organic-organic (O-O) heterojunction was fabricated by using the thin films of a hole transporting material, copper phthalocyanine (CuPc) and an electron transporting material, copper hexadecafluoro-phthalocyanine (F16CuPc). The nanostructured thin films were characterized by optical absorption spectra, FESEM, AFM, X-ray diffraction, etc. Grain size of CuPc and F16CuPc on the substrate surface was different. XRD analysis shows that the crystallinity of the double layer films/heterojunction decreases as compared to the single layer film. The heterojunction sandwich structure ITO/F16CuPc/CuPc/Al, in the present study has shown a good diode like current-voltage (I-V) characteristics with reverse rectifying characteristics. In addition, electrical switching and hysteresis phenomena have also been observed in both sides of the voltage polarities. Interestingly, the single layer sandwich structure of the type ITO/CuPc/Al and ITO/F16CuPc/Al did not show any noticeable electrical switching and hysteresis in I-V characteristics as compared to double layer heterostructure. The reverse rectification has been explained on the basis of band bending due to the accumulation of charge carriers near the junction and the electrical switching has been explained considering the charge carriers trapping and detrapping at the O-O interface. PMID:23646732

Chowdhury, Avijit; Biswas, Bipul; Bera, Raghu Nath; Mallik, Biswanath

2013-01-01

341

Hydrophobic/superhydrophobic oxidized metal surfaces showing negligible contact angle hysteresis.  

PubMed

Dynamic wettability of oxidized metal (aluminum and titanium) surfaces could be tuned by chemical vapor deposition (CVD) of 1,3,5,7-tetramethylcyclotetrasiloxane (D(4)(H)). This facile CVD method produces not only monomeric layers but also particulate films by changing the CVD temperature, resulting in a marked difference in the final wetting properties. In the samples prepared at 80°C for ~3 days, D(4)(H) layers with thicknesses of ~0.5 nm were formed on the surfaces without discernible change in surface morphology, as evidenced by X-ray photoelectron spectroscopy and atomic force microscopy. After this D(4)(H) monomeric layer formation, the hydrophilic oxidized aluminum and titanium surfaces became hydrophobic (advancing/receding water contact angles (?(A)/?(R))=102-104°/99-102°) showing essentially negligible contact angle hysteresis. Performing CVD of D(4)(H) at 180°C for ~1 day produced opaque film with particulate morphologies with diameters in the range of 500 nm to 4 ?m observed on the surfaces. This geometric morphology enhanced the surface hydrophobicity (?(A)/?(R)=163°/160-161°). Droplets on these negligible-hysteresis surfaces moved very easily without "pinning". PMID:20970808

Hozumi, Atsushi; Cheng, Dalton F; Yagihashi, Makoto

2011-01-15

342

Torque from hysteresis machines with type-II superconducting segmented rotors  

NASA Astrophysics Data System (ADS)

Electrical machines having rotors constructed from different numbers of type-II superconducting segments have been modelled numerically. The hollow cylindrical rotors are subjected to a rotating applied field that induces currents in the superconducting pieces and the resulting torque is evaluated. The mathematical technique used is based on the critical state model and solves for the current and field distributions within the superconducting pieces using the finite element method. In a two-pole rotating field, a rotor made from two half-ringed pieces is found to behave like a reluctance machine, having a larger peak torque than hysteresis type rotors constructed from other numbers of segments. In general, splitting the rotor up into more segments is advantageous when the flux penetration is small since this increases the hysteresis loss and equivalently, the torque. The modelling results indicate the number of segments which will result in the largest torque for a given rotor size, material critical current density and applied field amplitude. Such information is valuable when considering the performance optimisation of such machines.

Barnes, G. J.; McCulloch, M. D.; Dew-Hughes, D.

2000-04-01

343

Energy dissipation due to viscosity during deformation of a capillary surface subject to contact angle hysteresis  

NASA Astrophysics Data System (ADS)

A capillary surface is the boundary between two immiscible fluids. When the two fluids are in contact with a solid surface, there is a contact line. The physical phenomena that cause dissipation of energy during a motion of the contact line are hysteresis in the contact angle dynamics, and viscosity of the fluids involved. In this paper, we consider a simplified problem where a liquid and a gas are bounded between two parallel plane surfaces with a capillary surface between the liquid-gas interface. The liquid-plane interface is considered to be non-ideal, which implies that the contact angle of the capillary surface at the interface is set-valued, and change in the contact angle exhibits hysteresis. We analyze a two-point boundary value problem for the fluid flow described by the Navier-Stokes and continuity equations, wherein a capillary surface with one contact angle is deformed to another with a different contact angle. The main contribution of this paper is that we show the existence of non-unique classical solutions to this problem, and numerically compute the dissipation.

Athukorallage, Bhagya; Iyer, Ram

2014-02-01

344

Using sharp transitions in contact angle hysteresis to move, deflect, and sort droplets on a superhydrophobic surface  

NASA Astrophysics Data System (ADS)

In order to make an effective droplet-based microfluidic device, one must be able to precisely control a number of key processes including droplet positioning, motion, coalescence, mixing, and sorting. In a typical three-dimensional device, these processes are well understood. However, for planar or open microfluidic devices, many of these processes have yet to be demonstrated. In this paper, a series of superhydrophobic surfaces created by sanding Teflon are used as the microfluidics platform. The superhydrophobic surfaces used in this study all have advancing contact angles of 150° but have contact angle hysteresis that were varied smoothly from 3° to 30° as the grit size of the sandpaper is changed. Drop motion was initiated by placing the surface on an inclined plane. To deflect and move droplets along the surface, single and multiple transition lines in receding contact angle were created by spatially varying the surface roughness of the Teflon. The degree of droplet deflection was studied as a function of droplet size, droplet speed, and the angle that the transition line in contact angle hysteresis made with the principle direction of droplet motion. Droplet deflections across a single transition as large as 140% the droplet diameter were observed. The droplet deflection was found to increase with increasing difference in contact angle hysteresis across the transition and increasing transition angles up to about 40°. The largest deflections were observed over a very narrow range of droplet velocities corresponding to a range in Weber numbers between 0.1 and 0.2. This narrow range in Weber number suggests that transitions in receding contact angle can be used to sort drops based on velocity, size or wetting properties with a strong degree of selectivity. The direction of deflection was observed to change depending on whether the drops transitioned from a region of low to high or high to low contact angle hysteresis. In a transition from low to high hysteresis, a large portion of the drop's kinetic energy is converted into interfacial energy as the receding contact line of the drop is deformed. Alternatively, a transition from high to low hysteresis results in some of the drop's interfacial energy converted into kinetic energy as the deformation of the droplet is reduced. The result is either a reduction or increase in the droplet's velocity normal to the line of transition depending on the sign of the transition in contact angle hysteresis. Finally, single and multiple stripes of different contact angle hysteresis are also shown to be effective at deflecting droplets.

Nilsson, Michael A.; Rothstein, Jonathan P.

2012-06-01

345

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

PubMed Central

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

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

2010-01-01

346

Cryogenic surface distortion and hysteresis of a 50 cm diameter fused silica mirror cooled to 77 K  

NASA Technical Reports Server (NTRS)

A 50 cm diameter, lightweight, Amersil TO8E, fused-natural-quartz mirror with a single arch cross section was tested at the NASA/Ames Research Center Cryogenic Optics Test Facility to measure cryogenic distortion and hysteresis. The mirror was cooled to 77 K in four serial tests and the mirror figure was measured with a phase-measuring interferometer. On the basis of the repeatability of room temperature and cryogenic optical measurements, it was determined that the Single Arch Mirror had no measurable hysteresis and displayed repeatable cryogenic distortion. The Cryogenic Optics Test Facility, optical and thermal test methods, test results, and measurement accuracy are described.

Young, Jeffrey A.; Howard, Steven D.; Augason, Gordon C.; Melugin, Ramsey K.

1990-01-01

347

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

E-print Network

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

Müller, Markus

348

Haemolymph osmolality and thermal hysteresis activity in 17 species of arthropods from subAntarctic Marion Island  

Microsoft Academic Search

In this paper, we present measurements of haemolymph osmolality for individuals from 17 species of arthropods on Marion Island, including a mite, a spider, Collembola, Psocoptera, Coleoptera, Diptera and Lepidoptera. This is the largest such survey for a Southern Hemisphere habitat. We also screened these species for thermal hysteresis activity, and show that the lepidopteran Embryonopsis halticella has a haemolymph

Brent J. Sinclair; Steven L. Chown

2002-01-01

349

Purification, composition, and physical properties of a thermal hysteresis "antifreeze" protein from larvae of the beetle, Tenebrio molitor.  

PubMed

Proteins which produce a thermal hysteresis (difference between the freezing and melting points) in aqueous solution are well-known for their antifreeze activity in polar marine fishes. Much less is known about the biology and biochemistry of similar antifreeze proteins found in certain insects. A thermal hysteresis protein was purified from cold acclimated larvae of the beetle, Tenebrio molitor, by using ethanol fractionation, DEAE ion-exchange chromatography, gel filtration, and high-pressure liquid chromatography. The purified protein had a molecular mass of 17 000 daltons and its N terminus was lysine. The amino acid composition of the antifreeze protein contained more hydrophilic amino acids than the fish antifreezes. This is consistent with the compositions of previously purified insect thermal hysteresis proteins. However, the percentage of hydrophilic amino acids in this Tenebrio antifreeze protein was considerably less than that of other insect thermal hysteresis proteins. The freezing point depressing activity of the Tenebrio antifreeze was less than that of fish proteins and glycoproteins at low protein concentrations but was greater at high protein concentrations. PMID:7074035

Tomchaney, A P; Morris, J P; Kang, S H; Duman, J G

1982-02-16

350

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

SciTech Connect

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

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

2006-07-15

351

Introducing Hysteresis in Snow Depletion Curves to Improve the Water Budget of a Land Surface Model in an Alpine Catchment  

E-print Network

Introducing Hysteresis in Snow Depletion Curves to Improve the Water Budget of a Land Surface Model), a distributed land surface model (LSM) with a multilayer, physically based snow model, has been applied of the accu- mulation and ablation of the snow cover using Moderate Resolution Imaging Spectroradiometer

352

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

SciTech Connect

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

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

2010-10-15

353

Unifying soil respiration pulses, inhibition, and temperature hysteresis through dynamics of labile soil carbon and O2  

NASA Astrophysics Data System (ADS)

and diel dynamics of soil respiration (Rs) strongly influence terrestrial carbon (C) emissions and are difficult to predict. Wetting events may cause a large pulse or strong inhibition of Rs. Complex diel dynamics include hysteresis in the relationship between Rs and soil temperature. The mechanistic basis for these dynamics is not well understood, resulting in large discrepancies between predicted and observed Rs. We present a unifying approach for interpreting these phenomena in a hot arid agricultural environment. We performed a whole ecosystem wetting experiment with continuous measurement of Rs to study pulse responses to wetting in a heterotrophic system. We also investigated Rs during cultivation of Sorghum bicolor to evaluate the role of photosynthetic C in the regulation of diel variation in Rs. Finally, we adapted a Rs model with sensitivity to soil O2 and water content by incorporating two soil C pools differing in lability. We observed a large wetting-induced pulse of Rs from the fallow field and were able to accurately simulate the pulse via release of labile soil C. During the exponential phase of plant growth, Rs was inhibited in response to wetting, which was accurately simulated through depletion of soil O2. Without plants, hysteresis was not observed; however, with growing plants, an increasingly significant counterclockwise hysteresis developed. Hysteresis was simulated via a dynamic photosynthetic C pool and was not likely controlled by physical processes. These results help characterize the complex regulation of Rs and improve understanding of these phenomena under warmer and more variable conditions.

Oikawa, P. Y.; Grantz, D. A.; Chatterjee, A.; Eberwein, J. E.; Allsman, L. A.; Jenerette, G. D.

2014-04-01

354

Analysis of the hysteresis loop in stainless steels II. Austenitic–ferritic duplex steel and the effect of nitrogen  

Microsoft Academic Search

The hysteresis loop of austenitic and austenitic–ferritic duplex stainless steels, both with different levels of nitrogen, was analyzed using a generalised statistical theory. The plot of the second derivative yields information on the average effective stress and the probability density function of the critical internal stresses, its evolution in cyclic straining and its dependence on the strain amplitude. The probability

Jaroslav Polák; Farouk Fardoun; Suzanne Degallaix

2001-01-01

355

Hysteresis during transition into improved mode on biasing experiment under the electrode current control in Tohoku University Heliac  

NASA Astrophysics Data System (ADS)

Electrode bias experiments were carried out in Tohoku University Heliac (TU-Heliac). This paper presents a comparison of the plasma behaviour in discharge of the electrode current ramped up with that ramped down to investigate the bifurcation and hysteresis phenomena. Bifurcation of the electrode current against the bias voltage, i.e. negative resistance and hysteresis between (1) electron stored energy and input power from the electrode, (2) fluctuation level of ion saturation current and radial electric field and (3) poloidal momentum damping force and poloidal Mach number were observed. The driving force in the region where the hysteresis was observed corresponded to those in the negative resistance phase and those were located at local maximum of the ion viscosity. Hysteresis between the poloidal Mach number and the poloidal damping force was observed. However, the difference in ion viscosity, which was obtained by subtracting the friction term from the total poloidal damping force, between the electrode current ramped up/down in the transition region was rather small. The data in the negative resistance region corresponded to those in the regime where the viscosity decreased against the poloidal Mach number.

Takahashi, H.; Yokoyama, M.; Kitajima, S.; Tanaka, Y.; Utoh, H.; Sasao, M.

2006-01-01

356

Hysteresis analysis of CoTi substituted M-type BaSr hexagonal ferrite Charanjeet Singh a,  

E-print Network

Hysteresis analysis of Co­Ti substituted M-type Ba­Sr hexagonal ferrite Charanjeet Singh a, , S.5Sr0.5CoxTixFe(12 - 2x)O19 ferrite have been investigated by XRD, SEM and VSM. XRD and SEM confirm M ferrites are known for their strong uniaxial magne- tocrystalline anisotropy with ease of magnetization

Koledintseva, Marina Y.

357

A simple fuzzy system for modelling of both rate-independent and rate-dependent hysteresis in piezoelectric actuators  

NASA Astrophysics Data System (ADS)

In this paper, a novel fuzzy system based method for modelling both rate-independent and rate-dependent hysteresis in the piezoelectric actuator is proposed. First, the partial Takagi-Sugeno (T-S) fuzzy rule is designed. The antecedent structure of the fuzzy system is identified through uniform partition of its input variable. Then, the parameters of the consequent structure are optimized via the recursive least squares (RLS) algorithm. The modelling method is simple to implement and highly efficient to compute. Experimental results show that the proposed method is efficient to model both rate-independent and rate-dependent hysteresis. Based on the inverse of the developed model, feed-forward hysteresis compensation experiments at the frequencies of 50 Hz and 100 Hz are also conducted with the hysteresis effects being obviously reduced. The major contribution of this paper is that the inverse of the model can be analytically computed and the method can be applied to the case of real-time on-line modelling.

Li, Pengzhi; Yan, Feng; Ge, Chuan; Wang, Xueliang; Xu, Lisong; Guo, Jialiang; Li, Peiyue

2013-03-01

358

Modeling, identification and feedforward control of multivariable hysteresis by combining Bouc-Wen equations and the inverse  

E-print Network

approach. I. INTRODUCTION Piezoelectric based actuators are widely used in micro- nano positioning actuators. One main characteristic of the considered hysteresis behavior is the strong couplings. To express-DOF actuators. Then we propose to combine the resulting multivariable model with the inverse

Paris-Sud XI, Université de

359

Diodelike and resistive hysteresis behavior of heterolayered BiFeO3/ZnO ferroelectric thin films  

NASA Astrophysics Data System (ADS)

BiFeO3/ZnO, ZnO/BiFeO3, BiFeO3/ZnO/BiFeO3, and ZnO/BiFeO3/ZnO thin film heterostructures were deposited on SrRuO3/Pt(111)/TiO2/SiO2/Si(100) substrates by off-axis radio frequency sputtering. Their diodelike and resistive hysteresis behavior are dependent on the combination sequence of the constituent layers in the heterostructures. Both the diodelike and resistive hysteresis behavior were clearly observed in BiFeO3/ZnO and ZnO/BiFeO3. The phenomena became more apparent with rising temperature. The behavior arises from the interface formed between BiFeO3 and ZnO. As expected, the diodelike and resistive hysteresis behavior are weakened and almost disappeared in the case of BiFeO3/ZnO/BiFeO3 and ZnO/BiFeO3/ZnO, where the two interfaces are equal and opposite to each other. The interface-limited Fowler-Nordheim tunneling in the high electric field region is demonstrated to involve in the formation of resistive hysteresis.

Wu, Jiagang; Wang, John

2010-11-01

360

Adaptive feed-forward hysteresis compensation for piezoelectric actuators Arnfinn Aas Eielsen, Jan Tommy Gravdahl, and Kristin Y. Pettersen  

E-print Network

Adaptive feed-forward hysteresis compensation for piezoelectric actuators Arnfinn Aas Eielsen, Jan Appl. Phys. Lett. 101, 032902 (2012) Origin of multiple memory states in organic ferroelectric field-effect transistors Appl. Phys. Lett. 101, 033304 (2012) Origin of multiple memory states in organic ferroelectric

Gravdahl, Jan Tommy

361

Hysteresis, avalanches, and disorder-induced critical scaling: A renormalization-group approach Karin Dahmen* and James P. Sethna  

E-print Network

Hysteresis, avalanches, and disorder-induced critical scaling: A renormalization-group approach is added, one finds a transition where the jump in the magnetization corresponding to an infinite avalanche avalanches , and universal behavior. We expand the critical exponents about mean-field theory in 6 dimensions

Sethna, James P.

362

Modeling of Nonlinear Hysteresis in Elastomers H.T. Banks, Gabriella A. Pint'er and Laura K. Potter  

E-print Network

Modeling of Nonlinear Hysteresis in Elastomers H.T. Banks, Gabriella A. Pint'er and Laura K. Potter in a class of filled elastomers. Quasi­static and dynamic models are presented in the context of simple of the scientific and engineering research required for a smart elastomer technology. Smart material structures

363

Dynamic hysteresis dispersion scaling of ferroelectric Nd-substituted Bi4Ti3O12 thin films  

NASA Astrophysics Data System (ADS)

The dynamics of ferroelectric hysteresis for Nd-substituted Bi4Ti3O12 thin films as a function of frequency and amplitude of time-varying external electric field is measured utilizing a Sawyer-Tower (ST) circuit. The frequency ranges from 1 to 106 Hz and the amplitude range is 101-400 kV cm-1. Given a fixed field amplitude E0, the hysteresis area A first grows and then decays with increasing frequency f. We study the characteristics of the dynamic order parameter Q against field amplitude E0. The frequency dependence of the hysteresis area over the low-frequency range can be expressed as A \\propto E_0^{2/3} f^{1/3} . However, over the high-frequency range, the frequency dependence takes the form A \\propto E_0^2 f^{-2/ 3} . We demonstrate that the hysteresis dispersion approaches its scaling state when the field amplitude E0 is higher than 170 kV cm-1, and a unique effective characteristic time tgr1 exists for the domain reversal that is inversely proportional to the field amplitude.

Liu, J.-M.; Pan, B.; Yu, H.; Zhang, S. T.

2004-03-01

364

Effects of hysteresis on redistribution of soil moisture and deep percolation at continuous and pulse drip irrigation  

Microsoft Academic Search

The infiltration and redistribution of soil moisture under surface drip irrigation considering hysteresis were investigated in two soils (loamy sand and silt loam) of different texture. The effect of continuous versus intermittent application of 1, 2 and 4l\\/h to the soils was evaluated in terms of wetting front advance patterns and deep percolation under the root zone. For this purpose,

S. Elmaloglou; E. Diamantopoulos

2009-01-01

365

Hysteresis, Switching and Anomalous Behaviour of a Quartz Tuning Fork in Superfluid 4He  

NASA Astrophysics Data System (ADS)

We have been studying the behaviour of commercial quartz tuning forks immersed in superfluid 4He and driven at resonance. For one of the forks we have observed hysteresis and switching between linear and non-linear damping regimes at temperatures below 10 mK. We associate linear damping with pure potential flow around the prongs of the fork, and non-linear damping with the production of vortex lines in a turbulent regime. At appropriate prong velocities, we have observed metastability of both the linear and the turbulent flow states, and a region of intermittency where the flow switched back and forth between each state. For the same fork, we have also observed anomalous behaviour in the linear regime, with large excursions in both damping, resonant frequency, and the tip velocity as a function of driving force.

Bradley, D. I.; Fear, M. J.; Fisher, S. N.; Guénault, A. M.; Haley, R. P.; Lawson, C. R.; Pickett, G. R.; Schanen, R.; Tsepelin, V.; Wheatland, L. A.

2014-04-01

366

Ultrasonic study of the gelation of gelatin: phase diagram, hysteresis and kinetics  

E-print Network

We map the ultrasonic (8 MHz) speed and attenuation of edible-grade gelatin in water, exploring the key dependencies on temperature, concentration and time. The ultrasonic signatures of the sol-gel transition, confirmed by rheological measurements, and incomplete gel formation at low concentrations, enable a phase diagram of the system to be constructed. Sensitivity is also demonstrated to the kinetics of gel formation and melting, and associated hysteresis effects upon cyclic temperature sweeps. Furthermore, simple acoustic models of the sol and gel state enable estimation of the speed of sound and compressibility of gelatin. Our results demonstrate the potential of ultrasonic measurements to characterise the structure and visco-elasticity of gelatin hydrogels.

Parker, N G

2010-01-01

367

Investigation of scaling laws in frequency-dependent minor hysteresis loops for ferromagnetic steels  

NASA Astrophysics Data System (ADS)

Scaling laws in dynamical magnetic minor hysteresis loops have been investigated in the magnetizing frequency range of 0.05-300 Hz for various steels including Cr-Mo-V steel subjected to creep, cold rolled steels, and plastically deformed Ni. Although scaling laws in the medium magnetization range found previously fail in the high magnetization frequency regime owing to a significant contribution of eddy currents, a scaling power law of the relation between remanence and remanence work of minor loops, associated with a constant exponent of approximately 1.9, holds true in a very low magnetization regime, irrespective of magnetization frequency and investigated materials. The coefficient of the law is proportionally related to Vickers hardness over the wide frequency range. These observations demonstrate that the scaling analysis of dynamical minor loops enables us to evaluate materials degradation in a short measurement time with low measurement field and high sensitivity to defect density.

Kobayashi, S.; Tsukidate, S.; Kamada, Y.; Kikuchi, H.; Ohtani, T.

2012-01-01

368

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

DOEpatents

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

Humphrey, Floyd B. (Bradfordwoods, PA)

1987-01-01

369

On the hysteresis of the sea surface and its applicability to wave height predictions  

NASA Technical Reports Server (NTRS)

Because of the low dissipation rate of wave energy on the ocean's surface, the wave height at some location and time must be dependent upon wind fields in existence there at previous times and upon swell propagated there from other regions. To study these relationships, significant wave height (SWH) measurements from the Geos-3 radar altimeter are used in conjunction with anemometer windspeed measurements from weather ships, L, C, and R. During the passage of large cyclonic disturbances near the fixed locations of these vessels in the North Atlantic in February 1976, distinct hysteresis profiles that characterize the sea's memory during generation and dissipation conditions are observed. Examples are given that demonstrate the influences of cyclone intensity, movement, velocity, and shape on the configuration of these profiles.

Parsons, C. L.

1977-01-01

370

Highly stable hysteresis-free carbon nanotube thin-film transistors by fluorocarbon polymer encapsulation.  

PubMed

We report hysteresis-free carbon nanotube thin-film transistors (CNT-TFTs) employing a fluorocarbon polymer (Teflon-AF) as an encapsulation layer. Such fluorocarbon encapsulation improves device uniformity with excellent operation stability in air and even in water. The fluoropolymers possess high hydrophobicity for efficient removal of water molecules from the vicinity of nanotubes, which are known to induce charge trapping. In addition, the strong dipole associated with the carbon-fluorine bonds can provide effective screening of the charge carriers in nanotubes from various trap states in the substrate. We also report on the extended applications of encapsulation with Teflon-AF for the realization of dual-gate CNT-TFTs, where one gate is used to control the threshold voltage and the other to switch the device. The fluorocarbon encapsulation technique presents a promising approach for enhanced device reliability, which is critical for future system-level electronics based on CNTs. PMID:24796606

Ha, Tae-Jun; Kiriya, Daisuke; Chen, Kevin; Javey, Ali

2014-06-11

371

Charge drive with active DC stabilization for linearization of piezoelectric hysteresis.  

PubMed

Charge drive circuits can significantly reduce piezoelectric nonlinearity; however, they are rarely used in practice because of their limited low-frequency performance, their dependence of voltage gain on the load capacitance, and their requirement for time-consuming tuning procedures. In this report, a new charge drive circuit is proposed that uses a controlled current source with voltage feedback to stabilize the low-frequency behavior. This approach eliminates many of the present difficulties and allows extremely low transition frequencies without a long transient response. Experimental results demonstrate that the proposed charge amplifier can effectively reduce piezoelectric hysteresis and creep to less than 1.3% at scan-rates of 10, 1, and 0.1 Hz. PMID:25004535

Fleming, Andrew J

2013-08-01

372

Manipulation of transport hysteresis on graphene field effect transistors with Ga ion irradiation  

NASA Astrophysics Data System (ADS)

We have studied the effect of Ga ion irradiation on the controllable hysteretic behavior of graphene field effect transistors fabricated on Si/SO2 substrates. The various densities of defects in graphene were monitored by Raman spectrum. It was found that the Dirac point shifted to the positive gate voltage constantly, while the hysteretic behavior was enhanced first and then weakened, with the dose of ion irradiation increasing. By contrasting the trap charges density induced by dopant and the total density of effective trap charges, it demonstrated that adsorbate doping was not the decisive factor that induced the hysteretic behavior. The tunneling between the defect sites induced by ion irradiation was also an important cause for the hysteresis.

Wang, Quan; Liu, Shuai; Ren, Naifei

2014-09-01

373

Discrete regenerative fuel cell reduces hysteresis for sustainable cycling of water  

NASA Astrophysics Data System (ADS)

The discrete regenerative fuel cell is being developed as a residential power control that synchronizes with a renewables load which fluctuates significantly with the time and weather. The power of proton exchange membrane fuel cells can be scaled-up adjustably to meet the residential power demand. As a result, scale-ups from a basic unit cell with a 25 cm2 active area create a serpentine flow-field on an active area of 100 cm2 and take into account the excessive current and the remaining power obtained by stacking single cells. Operating a fuel cell utilising oxygen produced by the electrolyser instead of air improves the electrochemical reaction and the water balance. Furthermore, the performance test results with oxygen instead of air show almost no hysteresis, which results in the very stable operation of the proton exchange membrane fuel cell as well as the sustainable cycle of water by hydrogen and oxygen mediums.

Park, Kiwon; Lee, Jungkoo; Kim, Hyung-Man; Choi, Kap-Seung; Hwang, Gunyong

2014-04-01

374

CMR of Co/Cu multilayers with reduced hysteresis and low-field response  

SciTech Connect

We present the results of a systematic study on optimization of the giant magnetoresistance (GMR) response in Co/Cu multilayers (MLs) for copper layer thickness near the second oscillatory peak. Co/Cu MLs with alternating thick (t(1)Co) and thin (t(2)Co) layers have been prepared in the from of [Cot(1)CoA/Cu20A/Cot(2)CoA/Cu20A]15. We have found that the magnetoresistive hysteresis of these MLs is reduced with decreasing t(2)Co and has disappeared when t(2)Co<4.5A. We have obtained an optimal GMR response with a field sensitivity of 0. 013%/Oe over a field region of -60 Oe centered at -50 Oe. This architecture may enable the use of Cu/Co MLs in low-field magnetic sensor applications.

Mao, M.; Gibbons, M.; Law, B.; Grabner, F.; Veron, S.; Cerjan, C.

1997-02-01

375

Discrete regenerative fuel cell reduces hysteresis for sustainable cycling of water  

PubMed Central

The discrete regenerative fuel cell is being developed as a residential power control that synchronizes with a renewables load which fluctuates significantly with the time and weather. The power of proton exchange membrane fuel cells can be scaled-up adjustably to meet the residential power demand. As a result, scale-ups from a basic unit cell with a 25?cm2 active area create a serpentine flow-field on an active area of 100?cm2 and take into account the excessive current and the remaining power obtained by stacking single cells. Operating a fuel cell utilising oxygen produced by the electrolyser instead of air improves the electrochemical reaction and the water balance. Furthermore, the performance test results with oxygen instead of air show almost no hysteresis, which results in the very stable operation of the proton exchange membrane fuel cell as well as the sustainable cycle of water by hydrogen and oxygen mediums. PMID:24699531

Park, Kiwon; Lee, Jungkoo; Kim, Hyung-Man; Choi, Kap-Seung; Hwang, Gunyong

2014-01-01

376

Stress hysteresis during thermal cycling of plasma-enhanced chemical vapor deposited silicon oxide films  

NASA Astrophysics Data System (ADS)

The mechanical response of plasma-enhanced chemical vapor deposited SiO2 to thermal cycling is examined by substrate curvature measurement and depth-sensing indentation. Film properties of deposition stress and stress hysteresis that accompanied thermal cycling are elucidated, as well as modulus, hardness, and coefficient of thermal expansion. Thermal cycling is shown to result in major plastic deformation of the film and a switch from a compressive to a tensile state of stress; both athermal and thermal components of the net stress alter in different ways during cycling. A mechanism of hydrogen incorporation and release from as-deposited silanol groups is proposed that accounts for the change in film properties and state of stress.

Thurn, Jeremy; Cook, Robert F.

2002-02-01

377

Hysteresis in a two-level system and frictional force in a standing light wave  

NASA Astrophysics Data System (ADS)

A quasi-classical solution to equations for the density matrix of a two-level atom in a standing light wave field is obtained. In adiabatic state representations, consideration is given to mixing which results from spontaneous emission and Landau-Zener (LZ) transitions. The solution is employed to ascertain the frictional force acting on the atom in a wide range of atomic and field parameters. In a strong field, friction results from hysteresis effects in excited transitions. At low velocities, this force is characterized by a narrow peak which is not broadened by the field (adiabatic resonance). Coherent shaking at the LZ transitions leads to an oscillating pattern in the frictional force.

Kazantsev, A. P.; Chudesnikov, D. O.; Iakovlev, V. P.

1986-05-01

378

Electric field controlled magnetic hysteresis loops in a Metglas®/PMN-PT heterostructure  

NASA Astrophysics Data System (ADS)

An electric field tunable magnetic hysteresis loop was studied in a multiferroic heterostructure consisting of a 25 µm thick Metglas® ribbon affixed to a lead magnesium niobate-lead titanate (PMN-PT) crystal. This multiferroic heterostructure exhibits a considerably strong converse magnetoelectric effect, CME = -80%, where CME = [M(E) - M(0)]/M(0), and a converse magnetoelectric coupling constant, A = 23 Oe cm kV-1, in the vicinity of the saturation electric polarization. This work systematically demonstrates the tunability of magnetic parameters including magnetization, coercivity, remanence and squareness, under the application of an electric field of 0-8 kV cm-1. Additionally, the physical mechanism of the CME is discussed. These results provide useful resources for the design of a new generation of electrically controlled devices.

Chen, Yajie; Fitchorov, Trifon; Cai, Zhuhua; Ziemer, K. S.; Vittoria, Carmine; Harris, V. G.

2010-04-01

379

Effect of surface texturing on superoleophobicity, contact angle hysteresis, and "robustness".  

PubMed

Previously, we reported the creation of a fluorosilane (FOTS) modified pillar array silicon surface comprising ~3-?m-diameter pillars (6 ?m pitch with ~7 ?m height) that is both superhydrophobic and superoleophobic, with water and hexadecane contact angles exceeding 150° and sliding angles at ~10° owing to the surface fluorination and the re-entrant structure in the side wall of the pillar. In this work, the effects of surface texturing (pillar size, spacing, and height) on wettability, contact angle hysteresis, and "robustness" are investigated. We study the static, advancing, and receding contact angles, as well as the sliding angles as a function of the solid area fraction. The results reveal that pillar size and pillar spacing have very little effect on the static and advancing contact angles, as they are found to be insensitive to the solid area fraction from 0.04 to ~0.4 as the pillar diameter varies from 1 to 5 ?m and the center-to-center spacing varies from 4.5 to 12 ?m. On the other hand, sliding angle, receding contact angle, and contact angle hysteresis are found to be dependent on the solid area fraction. Specifically, receding contact angle decreases and sliding angle and hysteresis increase as the solid area fraction increases. This effect can be attributable to the increase in pinning as the solid area fraction increases. Surface Evolver modeling shows that water wets and pins the pillar surface whereas hexadecane wets the pillar surface and then penetrates into the side wall of the pillar with the contact line pinning underneath the re-entrant structure. Due to the penetration of the hexadecane drop into the pillar structure, the effect on the receding contact angle and hysteresis is larger relative to that of water. This interpretation is supported by studying a series of FOTS pillar array surfaces with varying overhang thickness. With the water drop, the contact line is pinned on the pillar surface and very little overhang thickness effect was observed. On the other hand, the hexadecane drop is shown to wet the pillar surface and the side wall of the overhang. It then pins at the lower edge of the overhang structure. A plot of the thickness of the overhang as a function of the static, advancing, and receding contact angles and sliding angle of hexadecane reveals that static, advancing, and receding contact angles decrease and sliding angle increases as the thickness of the overhang increases. A larger overhang effect is observed with octane due to its lower surface tension. The robustness of the pillar array surface against external pressure induced wetting and abrasion was modeled. Surface Evolver simulation (with the hexadecane drop) indicates that wetting breakthrough pressure as high as ~70 kPa is achievable with 0.5-?m-diameter pillar array FOTS surfaces. Mechanical modeling shows that bending of the pillars is the key failure by abrasion, which can be avoided with a short pillar structure. The path to fabricate a superoleophobic surface that can withstand the external force equivalent of a gentle cleaning blade (up to ~30 kPa) without wetting and abrasion failure is discussed. PMID:22992132

Zhao, Hong; Park, Kyoo-Chul; Law, Kock-Yee

2012-10-23

380

A unified model of hysteresis and long-time relaxation in heterogeneous materials  

NASA Astrophysics Data System (ADS)

A physical model of stress-strain dynamics and long-time relaxation (slow time) in structured media is proposed. The model is based on the analysis of inter-grain contacts and the resulting surface force potential with a barrier. The result is a unified description of the classical acoustic nonlinearity, stress-strain hysteresis, and logarithmic relaxation law for sound velocity (and, hence, for the frequency of nonlinear resonance in samples of structured materials). Estimates of a characteristic volume of interacting contacts give close values for the variety of consolidated materials. For weak (linear) testing waves, the logarithmic relaxation occurs if a classical quadratic nonlinearity is added to the stress-strain relation.

Lebedev, A. V.; Ostrovsky, L. A.

2014-09-01

381

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

PubMed

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

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

2014-01-24

382

Mechanical characterization of journal superconducting magnetic bearings: stiffness, hysteresis and force relaxation  

NASA Astrophysics Data System (ADS)

Superconducting magnetic bearings (SMBs) can provide stable levitation without direct contact between them and a magnetic source (typically a permanent magnet). In this context, superconducting magnetic levitation provides a new tool for mechanical engineers to design non-contact mechanisms solving the tribological problems associated with contact at very low temperatures. In the last years, different mechanisms have been proposed taking advantage of superconducting magnetic levitation. Flywheels, conveyors or mechanisms for high-precision positioning. In this work the mechanical stiffness of a journal SMBs have been experimentally studied. Both radial and axial stiffness have been considered. The influence of the size and shape of the permanent magnets (PM), the size and shape of the HTS, the polarization and poles configuration of PMs of the journal SMB have been studied experimentally. Additionally, in this work hysteresis behavior and force relaxation are considered because they are essential for mechanical engineer when designing bearings that hold levitating axles.

Cristache, Cristian; Valiente-Blanco, Ignacio; Diez-Jimenez, Efren; Alvarez-Valenzuela, Marco Antonio; Pato, Nelson; Perez-Diaz, Jose Luis

2014-05-01

383

Numerical simulation of dune-flat bed transition and stage-discharge relationship with hysteresis effect  

USGS Publications Warehouse

This work presents recent advances on morphodynamic modeling of bed forms under unsteady discharge. This paper includes further development of a morphodynamic model proposed earlier by Giri and Shimizu (2006a). This model reproduces the temporal development of river dunes and accurately replicates the physical properties associated with bed form evolution. Model results appear to provide accurate predictions of bed form geometry and form drag over bed forms for arbitrary steady flows. However, accurate predictions of temporal changes of form drag are key to the prediction of stage-discharge relation during flood events. Herein, the model capability is extended to replicate the dune-flat bed transition, and in turn, the variation of form drag produced by the temporal growth or decay of bed forms under unsteady flow conditions. Some numerical experiments are performed to analyze hysteresis of the stage-discharge relationship caused by the transition between dune and flat bed regimes during rising and falling stages of varying flows. The numerical model successfully simulates dune-flat bed transition and the associated hysteresis of the stage-discharge relationship; this is in good agreement with physical observations but has been treated in the past only using empirical methods. A hypothetical relationship for a sediment parameter (the mean step length) is proposed to a first level of approximation that enables reproduction of the dune-flat bed transition. The proposed numerical model demonstrates its ability to address an important practical problem associated with bed form evolution and flow resistance in varying flows. Copyright 2009 by the American Geophysical Union.

Shimizu, Y.; Giri, S.; Yamaguchi, S.; Nelson, J.

2009-01-01

384

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

PubMed

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

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

2014-01-01

385

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

386

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

387

The Impact of Shallow-Trench-Isolation Mechanical Stress on the Hysteresis Effect of Partially Depleted Silicon-on-Insulator n-Type Metal-Oxide-Semiconductor Field Effects  

NASA Astrophysics Data System (ADS)

The impact of shallow trench isolation (STI) mechanical stress on the hysteresis effect in the output characteristics is measured in partially depleted (PD) silicon-on-insulator (SOI) metal-oxide-semiconductor field effect transistors (MOSFETs). We develop ID hysteresis, which is defined as the difference between ID versus VD forward sweep and reverse sweep. The fabricated devices show positive and negative peaks in ID hysteresis. The experimental results show that ID hysteresis declined as the STI mechanical stress increases. We also elaborate on the impact of STI mechanical stress on the ID hysteresis of PD SOI n-type MOSFETs.

Luo, Jie-Xin; Chen, Jing; Chai, Zhan; Lü, Kai; He, Wei-Wei; Yang, Yan; Wang, Xi

2014-12-01

388

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

389

Influence of hydraulic hysteresis on the mechanical behavior of unsaturated soils and interfaces  

NASA Astrophysics Data System (ADS)

Unsaturated soils are commonly widespread around the world, especially at shallow depths from the surface. The mechanical behavior of this near surface soil is influenced by the seasonal variations such as rainfall or drought, which in turn may have a detrimental effect on many structures (e.g. retaining walls, shallow foundations, mechanically stabilized earth walls, soil slopes, and pavements) in contact with it. Thus, in order to better understand this behavior, it is crucial to study the complex relationship between soil moisture content and matric suction (a stress state variable defined as pore air pressure minus pore water pressure) known as the Soil Water Characteristic Curve (SWCC). In addition, the influence of hydraulic hysteresis on the behavior of unsaturated soils, soil-structure interaction (i.e. rough and smooth steel interfaces, soil-geotextile interfaces) and pavement subgrade (depicted herein mainly by resilient modulus, Mr) was also studied. To this end, suction-controlled direct shear tests were performed on soils, rough and smooth steel interfaces and geotextile interface under drying (D) and wetting after drying (DW). The shearing behavior is examined in terms of the two stress state variables, matric suction and net normal stress. Results along the D and DW paths indicated that peak shear strength increased with suction and net normal stress; while in general, the post peak shear strength was not influenced by suction for rough interfaces and no consistent trend was observed for soils and soil-geotextiles interfaces. Contrary to saturated soils, results during shearing at higher suction values (i.e. 25 kPa and above) showed a decrease in water content eventhough the sample exhibited dilation. A behavior postulated to be related to disruption of menisci and/or non-uniformity of pore size which results in an increase in localized pore water pressures. Interestingly, wetting after drying (DW) test results showed higher peak and post peak shear strength than that of the drying (D) tests. This is believed to be the result of many factors such as: (1) cyclic suction stress loading, (2) water content (less on wetting than drying), and (3) type of soil. The cyclic suction loading may have induced irrecoverable plastic strains, resulting in stiffer samples for wetting tests as compared to drying. Additionally, water may be acting as a lubricant and thus resulting in lower shear strength for test samples D with higher water contents than DW samples. Furthermore, various shear strength models were investigated for their applicability to the experimental data. Models were proposed for the prediction of shear strength with suction based on the SWCC. The models are able to predict the shear strength of unsaturated soil and interfaces due to drying and wetting (i.e. hydraulic hysteresis) by relating directly to the SWCC. The proposed models were used and partly validated by predicting different test results from the literature. In addition, an existing elastoplastic constitutive model was investigated and validated by comparing the predicted and experimental (stress-displacement, volume change behavior) results obtained from rough and geotextile interface tests. This study also explores the effect of hydraulic hysteresis on the resilient modulus (Mr) of subgrade soils. Suction-controlled Mr tests were performed on compacted samples along the primary drying, wetting, secondary drying and wetting paths. Two test types were performed to check the effect of cyclic deviatoric stress loading on the results. First, M r tests were performed on the same sample at each suction (i.e. 25, 50, 75, 100 kPa) value along all the paths (drying, wetting etc.). A relationship between resilient modulus (Mr) and matric suction was obtained and identified as the resilient modulus characteristic curve (MRCC). MRCC results indicated that Mr increased with suction along the drying curve. On the other hand, results on the primary wetting indicated higher Mr than that of the primary drying and the secondary drying. The second type of test

Khoury, Charbel N.

390

The influence of hysteresis on the determination of the magnetocaloric effect in Gd5Si2Ge2  

NASA Astrophysics Data System (ADS)

We present a non-equilibrium Preisach-type hysteresis model based on the first order magnetocaloric material Gd5Si2Ge2. The model is developed from isofield magnetization measurements and first order reversal curves, both of which constitute a new and detailed approach to characterizing and modelling magnetocaloric materials. It is shown that the model reproduces the magnetization data, directly measured adiabatic temperature changes and provides a good description of the material behavior under application conditions. We find that the material settles in an area of metastability under continuous magnetization cycles, which effectively limits the adiabatic temperature change by the amount of thermal hysteresis present. We suggest a straightforward method for realistic estimation of the magnetocaloric effect from indirect measurements.

von Moos, L.; Bahl, C. R. H.; Nielsen, K. K.; Engelbrecht, K.

2015-01-01

391

Investigation of hysteresis in high current ion beam guiding through micro-glass capillary: time and dimension dependence  

NASA Astrophysics Data System (ADS)

Guiding of high current density (0.1–3?A?m?2) argon ion beams through a straight and tapered micro-glass-capillary is studied. It is observed that the ion beam requires a minimum threshold energy to pass through the capillary. The variation of beam current with applied voltage exhibits hysteresis due to the charges accumulated on the inner wall of the capillary. The dependence of hysteresis and beam transmission on the time interval between successive experiments including capillary dimensions and geometry are investigated. The guiding capability of a tapered capillary is demonstrated where beam size reduction without compromising total current is achieved. A particle-in-cell simulation code, developed by solving the Poisson’s equation and the equation of motion simultaneously, shows reasonable agreement with the experimental results.

Paul, Samit; Bhattacharjee, Sudeep

2015-01-01

392

A new stator-flux orientation strategy for flux-switching permanent magnet motor based on current-hysteresis control  

NASA Astrophysics Data System (ADS)

A stator-flux orientation strategy based on current hysteresis for the flux-switching permanent magnet (FSPM) motor is proposed, in which the stator-PM FSPM motor is considered as a conventional rotor-PM surface-mounted motor and an equivalent rotor-orientated dq-axes synchronous reference frame is built although there are actually no rotary magnetic motive force produced by the stator magnets in the FSPM motor. Based on the proposed model, a vector-control strategy with current hysteresis for the FSPM motor drive is investigated and implemented on a dSPACE-based platform, and both the simulated and experimental results validate the effectiveness. It should be emphasized that the proposed stator-flux orientation strategy can be applied to other stator-PM machines (including doubly salient and flux-reversal PM machines) and other control methods (including space-vector pulsed-width-modification and direct torque control).

Hua, Wei; Cheng, Ming; Lu, Wei; Jia, Hongyun

2009-04-01

393

Behavior of dissolved and total phosphorus concentration and stream discharge: The form of hysteresis during storm events  

NASA Astrophysics Data System (ADS)

The forms, rotational patterns and trends of hysteretic loops of dissolved and total phosphorus were investigated in the watershed of a New York City drinking water reservoir. We evaluated two biogeochemical parameters summarizing the changes in solute concentrations and the overall dynamics of each hysteretic loop and seven hydrological parameters that characterize the hydrograph formation of particular storm events. The objectives of this study are: (1) to examine whether the characteristics of solute hysteretic loops monitored during the summer, winter and spring seasons followed a consistent and recurring pattern, (2) to identify hydrological parameters which could potentially influence features of dissolved and total phosphorus hysteresis. Relationships between hysteresis features and hydrological parameters at the watershed outlet were explored using multivariate redundancy analysis (RDA).

Pradhanang, S. M.; Samal, N. R.; Pierson, D. C.; Schneiderman, E. M.; Zion, M. S.

2013-12-01

394

Light-induced hysteresis and recovery behaviors in photochemically activated solution-processed metal-oxide thin-film transistors  

NASA Astrophysics Data System (ADS)

In this report, photo-induced hysteresis, threshold voltage (VT) shift, and recovery behaviors in photochemically activated solution-processed indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) are investigated. It was observed that a white light illumination caused negative VT shift along with creation of clockwise hysteresis in electrical characteristics which can be attributed to photo-generated doubly ionized oxygen vacancies at the semiconductor/gate dielectric interface. More importantly, the photochemically activated IGZO TFTs showed much reduced overall VT shift compared to thermally annealed TFTs. Reduced number of donor-like interface states creation under light illumination and more facile neutralization of ionized oxygen vacancies by electron capture under positive gate potential are claimed to be the origin of the less VT shift in photochemically activated TFTs.

Jo, Jeong-Wan; Kim, Yong-Hoon; Park, Sung Kyu

2014-07-01

395

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

SciTech Connect

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

Chen, P.J.

1982-01-01

396

Origin and elimination of photocurrent hysteresis by fullerene passivation in CH3NH3PbI3 planar heterojunction solar cells.  

PubMed

The large photocurrent hysteresis observed in many organometal trihalide perovskite solar cells has become a major hindrance impairing the ultimate performance and stability of these devices, while its origin was unknown. Here we demonstrate the trap states on the surface and grain boundaries of the perovskite materials to be the origin of photocurrent hysteresis and that the fullerene layers deposited on perovskites can effectively passivate these charge trap states and eliminate the notorious photocurrent hysteresis. Fullerenes deposited on the top of the perovskites reduce the trap density by two orders of magnitude and double the power conversion efficiency of CH3NH3PbI3 solar cells. The elucidation of the origin of photocurrent hysteresis and its elimination by trap passivation in perovskite solar cells provides important directions for future enhancements to device efficiency. PMID:25503258

Shao, Yuchuan; Xiao, Zhengguo; Bi, Cheng; Yuan, Yongbo; Huang, Jinsong

2014-01-01

397

Origin and elimination of photocurrent hysteresis by fullerene passivation in CH3NH3PbI3 planar heterojunction solar cells  

NASA Astrophysics Data System (ADS)

The large photocurrent hysteresis observed in many organometal trihalide perovskite solar cells has become a major hindrance impairing the ultimate performance and stability of these devices, while its origin was unknown. Here we demonstrate the trap states on the surface and grain boundaries of the perovskite materials to be the origin of photocurrent hysteresis and that the fullerene layers deposited on perovskites can effectively passivate these charge trap states and eliminate the notorious photocurrent hysteresis. Fullerenes deposited on the top of the perovskites reduce the trap density by two orders of magnitude and double the power conversion efficiency of CH3NH3PbI3 solar cells. The elucidation of the origin of photocurrent hysteresis and its elimination by trap passivation in perovskite solar cells provides important directions for future enhancements to device efficiency.

Shao, Yuchuan; Xiao, Zhengguo; Bi, Cheng; Yuan, Yongbo; Huang, Jinsong

2014-12-01

398

Testing for the presence and source of nonstationarity in United States energy efficiency: Time trends, hysteresis or random walk?  

Microsoft Academic Search

This research tests for the presence and source of non-stationarity in U.S. aggregate energy efficiency for the 1900-1991 period. An outlier\\/intervention model is used to test for the presence of a unit-root in aggregate energy efficiency against the alternative hypothesis of a segmented\\/broken trend. A decomposed energy price model is also used to test if hysteresis in energy efficiency results

Paul Francis McArdle

1997-01-01

399

Systematic errors in free energy perturbation calculations due to a finite sample of configuration space: Sample-size hysteresis  

SciTech Connect

Although the free energy perturbation procedure is exact when an infinite sample of configuration space is used, for finite sample size there is a systematic error resulting in hysteresis for forward and backward simulations. The qualitative behavior of this systematic error is first explored for a Gaussian distribution, then a first-order estimate of the error for any distribution is derived. To first order the error depends only on the fluctuations in the sample of potential energies, {Delta}E, and the sample size, n, but not on the magnitude of {Delta}E. The first-order estimate of the systematic sample-size error is used to compare the efficiencies of various computing strategies. It is found that slow-growth, free energy perturbation calculations will always have lower errors from this source than window-growth, free energy perturbation calculations for the same computing effort. The systematic sample-size errors can be entirely eliminated by going to thermodynamic integration rather than free energy perturbation calculations. When {Delta}E is a very smooth function of the coupling parameter, {lambda}, thermodynamic integration with a relatively small number of windows is the recommended procedure because the time required for equilibration is reduced with a small number of windows. These results give a method of estimating this sample-size hysteresis during the course of a slow-growth, free energy perturbation run. This is important because in these calculations time-lag and sample-size errors can cancel, so that separate methods of estimating and correcting for each are needed. When dynamically modified window procedures are used, it is recommended that the estimated sample-size error be kept constant, not that the magnitude of {Delta}E be kept constant. Tests on two systems showed a rather small sample-size hysteresis in slow-growth calculations except in the first stages of creating a particle, where both fluctuations and sample-size hysteresis are large.

Wood, R.H.; Muehlbauer, W.C.F. (Univ. of Delaware, Newark (United States)); Thompson, P.T. (Swarthmore Coll., PA (United States))

1991-08-22

400

Evaporation stains: suppressing the coffee-ring effect by contact angle hysteresis.  

PubMed

A ring-shaped stain is frequently left on a substrate by a drying drop containing colloids as a result of contact line pinning and outward flow. In this work, however, different patterns are observed for drying drops containing small solutes or polymers on various hydrophilic substrates. Depending on the surface activity of solutes and the contact angle hysteresis (CAH) of substrates, the pattern of the evaporation stain varies, including a concentrated stain, a ringlike deposit, and a combined structure. For small surface-inactive solutes, the concentrated stain is formed on substrates with weak CAH, for example, copper sulfate solution on silica glass. On the contrary, a ringlike deposit is developed on substrates with strong CAH, for example, a copper sulfate solution on graphite. For surface-active solutes, however, the wetting property can be significantly altered and the ringlike stain is always visible, for example, Brij-35 solution on polycarbonate. For a mixture of surface-active and surface-inactive solutes, a combined pattern of a ringlike and concentrated stain can appear. For various polymer solutions on polycarbonate, similar results are observed. Concentrated stains are formed for weak CAH such as sodium polysulfonate, and ring-shaped patterns are developed for strong CAH such as poly(vinyl pyrrolidone). The stain pattern is actually determined by the competition between the time scales associated with contact line retreat and solute precipitation. The suppression of the coffee-ring effect can thus be acquired by the control of CAH. PMID:23721254

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

2013-06-25

401

Phase transition and hysteresis loop in structured games with global updating  

NASA Astrophysics Data System (ADS)

We present a global payoff-based strategy updating model for studying cooperative behavior of a networked population. We adopt the Prisoner’s Dilemma game and the snowdrift game as paradigms for characterizing the interactions among individuals. We investigate the model on regular, small-world, and scale-free networks, and find multistable cooperation states depending on the initial cooperator density. In particular for the snowdrift game on small-world and scale-free networks, there exist a discontinuous phase transition and hysteresis loops of cooperator density. We explain the observed properties by theoretical predictions and simulation results of the average number of neighbors of cooperators and defectors, respectively. Our work indicates that individuals with more neighbors have a trend to preserve their initial strategies, which has strong impacts on the strategy updating of individuals with fewer neighbors; while the fact that individuals with few neighbors have to become cooperators to avoid gaining the lowest payoff plays significant roles in maintaining and spreading of cooperation strategy.

Wang, Wen-Xu; Lü, Jinhu; Chen, Guanrong; Hui, P. M.

2008-04-01

402

A two-dimensional adsorption kinetic model for thermal hysteresis activity in antifreeze proteins.  

PubMed

Antifreeze proteins (AFPs) and antifreeze glycoproteins (AFGPs), collectively abbreviated as AF(G)Ps, are synthesized by various organisms to enable their cells to survive in subzero environments. Although the AF(G)Ps are markedly diverse in structure, they all function by adsorbing to the surface of embryonic ice crystals to inhibit their growth. This adsorption results in a freezing temperature depression without an appreciable change in the melting temperature. The difference between the melting and freezing temperatures, termed thermal hysteresis (TH), is used to detect and quantify the antifreeze activity. Insights from crystallographic structures of a number of AFPs have led to a good understanding of the ice-protein interaction features. Computational studies have focused either on verifying a specific model of AFP-ice interaction or on understanding the protein-induced changes in the ice crystal morphology. In order to explain the origin of TH, we propose a novel two-dimensional adsorption kinetic model between AFPs and ice crystal surfaces. The validity of the model has been demonstrated by reproducing the TH curve on two different beta-helical AFPs upon increasing the protein concentration. In particular, this model is able to accommodate the change in the TH behavior observed experimentally when the size of the AFPs is increased systematically. Our results suggest that in addition to the specificity of the AFPs for the ice, the coverage of the AFPs on the ice surface is an equally necessary condition for their TH activity. PMID:16774359

Li, Q Z; Yeh, Y; Liu, J J; Feeney, R E; Krishnan, V V

2006-05-28

403

Metastable nanobubbles at the solid-liquid interface due to contact angle hysteresis.  

PubMed

Nanobubbles exist at solid-liquid interfaces between pure water and hydrophobic surfaces with very high stability, lasting in certain cases up to several days. Not only semispherical but also other shapes, such as micropancakes, are known to exist at such interfaces. However, doubt has been raised as to whether or not the nanobubbles are gas-phase entities. In this study, surface nanobubbles at a pure water-highly ordered pyrolytic graphite (HOPG) interface were investigated by peak force quantitative nanomechanics (PF-QNM). Multiple isolated nanobubbles generated by the solvent-exchange method were present on the terraced areas, avoiding the steps of the HOPG surface. Adjacent nanobubbles coalesced and formed metastable nanobubbles. Coalescence was enhanced by the PF-QNM measurement. We determined that nanobubbles can exist for a long time because of nanoscale contact angle hysteresis at the water-HOPG interface. Moreover, the hydrophilic steps of HOPG were avoided during coalescence, providing evidence that the nanobubbles are truly gas phase. PMID:25540821

Nishiyama, Takashi; Yamada, Yutaka; Ikuta, Tatsuya; Takahashi, Koji; Takata, Yasuyuki

2015-01-27

404

Bistability and hysteresis in the emergence of pulses in microstrip Gunn-diode circuits  

NASA Astrophysics Data System (ADS)

We develop time-domain simulations of microwave and THz radiation sources built as arrays of active devices when the radiation wavelength is small as compared to spacing between electronic components. We pursue an approach when the system is represented by equations with time-delay feedback that could generate chaos and other forms of complicated dynamics. The approach simplifies simulations of ultra-wideband effects and exceeds capabilities of frequency-domain methods. As a model case, we simulated a microstrip circuit with Gunn diode and a remote resonator emitting the radiation towards infinity. We observed the emergence of either the continuous waves or the trains of high-frequency pulses depending on the bias conditions. We found bistability and hysteresis in the onset of different oscillation modes that depends on the way of driving the bias voltage into the domain of instability of the given system. The results would allow one to improve the design of THz radiation sources with time-delay coupling between components.

Yurchenko, V. B.; Yurchenko, L. V.

2014-12-01

405

Lattice water molecules tuned spin-crossover for an iron(II) complex with thermal hysteresis.  

PubMed

A new iron(II) complex based on the 4,4'-dimethyl-2,2'-bipyridine ligand [Fe(4,4'-dmbpy)3(ClO4)(SCN)·3H2O (1·3H2O)] has been prepared and characterized. Structural studies and Hirshfeld surface analysis for complex 1·3H2O at three different temperatures (300, 240 and 130 K) are described. The UV-vis absorption spectrum of a water-free sample (1) in methanol solution and magnetic susceptibility measurements for solid-state samples 1·3H2O and 1 revealed that the removal of lattice water molecules from complex 1·3H2O changed the magnetic properties from the low-spin state (1·3H2O) to the complete spin-crossover (1) between 350-220 K with a thermal hysteresis of 7 K, and was accompanied by a colour change from brown to red. PMID:25301143

Luo, Yang-Hui; Yang, Li-Jing; Liu, Qing-Ling; Ling, Yang; Wang, Wei; Sun, Bai-Wang

2014-11-28

406

Design of Mechanisms for Deployable, Optical Instruments: Guidelines for Reducing Hysteresis  

NASA Technical Reports Server (NTRS)

This paper is intended to facilitate the development of deployable, optical instruments by providing a rational approach for the design, testing, and qualification of high-precision (i.e., low-hysteresis) deployment mechanisms for these instruments. Many of the guidelines included herein come directly from the field of optomechanical engineering, and are, therefore, neither newly developed guidelines, nor are they uniquely applicable to the design of high-precision deployment mechanisms. This paper is to be regarded as a guide to design and not a set of NASA requirements, except as may be defined in formal project specifications. Furthermore, due to the rapid pace of advancement in the field of precision deployment, this paper should be regarded as a preliminary set of guidelines. However, it is expected that this paper, with revisions as experience may indicate to be desirable, might eventually form the basis for a set of uniform design requirements for high-precision deployment mechanisms on future NASA space-based science instruments.

Lake, Mark S.; Hachkowski, M. Roman

2000-01-01

407

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

NSDL National Science Digital Library

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

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

2009-04-14

408

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

NASA Astrophysics Data System (ADS)

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

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

2008-02-01

409

Thin-Film Ferro Electric-Coupled Microstripline Phase Shifters With Reduced Device Hysteresis  

NASA Technical Reports Server (NTRS)

This work deals with the performance of coupled microstripline phase shifters (CMPS) fabricated using BaxSr 1 -xTiO 3 (BST) ferroelectric thin films. The CMPS were fabricated using commercially available pulsed laser deposition BST films with Ba:Sr ratios of 30:70 and 20:80. Microwave characterization of these CMPS was performed at upper Kuband frequencies, particularly at frequencies near 16 and 18 GHz. X-ray diffraction studies indicate that the 30:70 films exhibit almost a 1:1 ratio between the in-plane and out-of-plane lattice parameters, suggesting that their cubics create strain -free films suitable for producing CMPS devices with reduced hysteresis in the paraelectric state. The quality of performance of the CMPS was studied based on their relative phase shift and insertion loss within the DC bias range of 0 to 400 V (i.e., E-field ranges within 0 to 53 V/micron). The performance of the CMPS was tested as a function of temperature to investigate their operation in the paraelectric, as well as in the ferroelectric, state (i.e., above and below the Curie temperature, respectively). The novel behavior discussed here is based on the experimental observation of the CMPS. This behavior, observed for the aforementioned cation ratio, highlights the relevance of good crystalline structure for high-quality CMPS.

Miranda, Felix A.; Romanofsky, Robert; Mueller, Carl H.; VanKeuls, Frederick

2010-01-01

410

A significant reduction of hysteresis in MnFe(P,Si) compounds  

NASA Astrophysics Data System (ADS)

The magnetocaloric effects in Mn1.3Fe0.7- x Co x P0.46Si0.54 compounds ( x = 0, 0.025, 0.05 and 0.1) were investigated systematically. X-ray diffraction shows that the compounds crystallize in the Fe2P-type hexagonal structure with space group P-62m symmetry. Magnetic measurements show that the paramagnetic-ferromagnetic transition temperatures range from 247 to 298 K. The maximal magnetic entropy changes in the Mn1.3Fe0.7P0.46Si0.54 compound reaches 8.3 J/kgK for a field change from 0 to 1.5 T. The thermal hysteresis of these compounds is less than 3 K. The maximum adiabatic temperature change is 2.2 K in Mn1.3Fe0.7P0.46Si0.54 and Mn1.3Fe0.65Co0.05P0.46Si0.54 compounds for a field change from 0 to 1.48 T, indicating this material system has potential for room-temperature magnetic refrigeration applications.

Huliyageqi, B.; Geng, Yao-xiang; Li, Ying-jie; Tegus, O.

2013-08-01

411

Drop motion induced by repeated stretching and relaxation on a gradient surface with hysteresis.  

PubMed

The motion of a droplet can be induced by periodically compressing and extending it between two similar gradient surfaces possessing significant wetting hysteresis. The shape fluctuation of the drop during repeated compression-extension cycles leads to its ratchetlike motion toward the region of higher wettability. A simple model requiring the volume preservation of the drop during the compression-extension cycles is sufficient to account for the effect and predict drop velocity across the surface when drop size and cycle frequency are specified. In connection with this study, we also report a variation of the standard vapor phase adsorption method of preparing a chemically graded surface that allows for good control over the steepness and the length of the active zone. The method can be used to produce a linear or a radial gradient, both of which are employed here to drive droplet motion along these patterns. This type of discrete droplet motion can be used to move drops on surfaces to transport materials within miniaturized digital fluidic devices. PMID:22950893

Longley, Jonathan E; Dooley, Erin; Givler, Douglas M; Napier, William J; Chaudhury, Manoj K; Daniel, Susan

2012-10-01

412

Hierarchically structured re-entrant microstructures for superhydrophobic surfaces with extremely low hysteresis  

NASA Astrophysics Data System (ADS)

This paper reports a new type of hierarchically structured surface consisting of re-entrant silicon micropillars with silicon nanowires atop for superhydrophobic surface with extremely low hysteresis. Re-entrant microstructures were fabricated on a silicon substrate through a customized one-mask microfabrication process while silicon nanopillars were created on the entire surface of microstructures, including sidewalls, by a metal-assisted-chemical etching process. The strategy of constructing hierarchical surfaces aims to reduce the actual contact area between liquid and top part of solid surface, thereby increasing the contact angle and reducing the sliding angle. The strategy of using re-entrant profile of the microstructure aims to prevent a liquid droplet from falling into cavities of roughened structures and decrease the actual contact area between the liquid droplet and sidewalls of solid structures, therefore reducing adhesion forces acting on the liquid droplet. Our measurement shows that the surface incorporating both hierarchical and re-entrant strategies exhibits a sliding angle as low as 0.5°, much lower than sliding angles of surfaces only incorporating either one of the strategies.

Hu, Huan; Swaminathan, Vikhram V.; Zamani Farahani, Mahmoud Reza; Mensing, Glennys; Yeom, Junghoon; Shannon, Mark A.; Zhu, Likun

2014-09-01

413

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

SciTech Connect

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

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

1996-06-01

414

Slip-stick wetting and large contact angle hysteresis on wrinkled surfaces.  

PubMed

Wetting on a corrugated surface that is formed via wrinkling of a hard skin layer formed by UV oxidation (UVO) of a poly(dimethylsiloxane) (PDMS) slab is studied using advancing and receding water contact angle measurements. The amplitude of the wrinkled pattern can be tuned through the pre-strain of the PDMS prior to surface oxidation. These valleys and peaks in the surface topography lead to anisotropic wetting by water droplets. As the droplet advances, the fluid is free to move along the direction parallel to the wrinkles, but the droplet moving orthogonal to the wrinkles encounters energy barriers due to the topography and slip-stick behavior is observed. As the wrinkle amplitude increases, anisotropy in the sessile droplet increases between parallel and perpendicular directions. For the drops receding perpendicular to the wrinkles formed at high strains, the contact angle tends to decrease steadily towards zero as the drop volume decreases, which can result in apparent hysteresis in the contact angle of over 100°. The wrinkled surfaces can exhibit high sessile and advancing contact angles (>115°), but the receding angle in these cases is generally vanishing as the drop is removed. This effect results in micrometer sized drops remaining in the grooves for these highly wrinkled surfaces, while the flat analogous UVO-treated PDMS shows complete removal of all macroscopic water drops under similar conditions. These wetting characteristics should be considered if these wrinkled surfaces are to be utilized in or as microfluidic devices. PMID:21145561

Bukowsky, Colton; Torres, Jessica M; Vogt, Bryan D

2011-02-15

415

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

PubMed

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

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

2004-05-01

416

Study of spin crossover nanoparticles thermal hysteresis using FORC diagrams on an Ising-like model  

NASA Astrophysics Data System (ADS)

Recent developments in the synthesis and characterization of spin crossover (SCO) nanoparticles and their prospects of switching at molecular level turned these bistable compounds into possible candidates for replacing the materials used in recording media industry for development of solid state pressure and temperature sensors or for bringing contributions in engineering. Compared to bulk samples with the same chemical structure, SCO nanoparticles display different characteristics of the hysteretic and relaxation properties like the shift of the transition temperature towards lower values along with decrease of the hysteresis width with nanoparticles size. Using an Ising-like model with specific boundary conditions within a Monte Carlo procedure, we here reproduce most of the hysteretic properties of SCO nanoparticles by considering the interaction between spin crossover edge molecules and embedding surfactant molecules and we propose a complex analysis concerning the effect of the interactions and sizes during the thermal transition in systems of SCO nanoparticles by using the First Order Reversal Curves diagram method and by comparison with similar effects in mixed crystal systems.

Atitoaie, Alexandru; Tanasa, Radu; Stancu, Alexandru; Enachescu, Cristian

2014-11-01

417

Breaking an Epigenetic Chromatin Switch: Curious Features of Hysteresis in Saccharomyces cerevisiae Telomeric Silencing  

PubMed Central

In addition to gene network switches, local epigenetic modifications to DNA and histones play an important role in all-or-none cellular decision-making. Here, we study the dynamical design of a well-characterized epigenetic chromatin switch: the yeast SIR system, in order to understand the origin of the stability of epigenetic states. We study hysteresis in this system by perturbing it with a histone deacetylase inhibitor. We find that SIR silencing has many characteristics of a non-linear bistable system, as observed in conventional genetic switches, which are based on activities of a few promoters affecting each other through the abundance of their gene products. Quite remarkably, our experiments in yeast telomeric silencing show a very distinctive pattern when it comes to the transition from bistability to monostability. In particular, the loss of the stable silenced state, upon increasing the inhibitor concentration, does not seem to show the expected saddle node behavior, instead looking like a supercritical pitchfork bifurcation. In other words, the ‘off’ state merges with the ‘on’ state at a threshold concentration leading to a single state, as opposed to the two states remaining distinct up to the threshold and exhibiting a discontinuous jump from the ‘off’ to the ‘on’ state. We argue that this is an inevitable consequence of silenced and active regions coexisting with dynamic domain boundaries. The experimental observations in our study therefore have broad implications for the understanding of chromatin silencing in yeast and beyond. PMID:25536038

Nagaraj, Vijayalakshmi H.; Mukhopadhyay, Swagatam; Dayarian, Adel; Sengupta, Anirvan M.

2014-01-01

418

Effect of preparation conditions on the hysteresis behavior of granular Fe-SiO 2  

NASA Astrophysics Data System (ADS)

The hysteresis behavior of Fe ?(SiO 2) 1- ? granular films was studied as a function of preparation conditions. The films were prepared by dc and rf magnetron sputtering over the composition range ?v = 0.1-0.9 volume fraction of Fe. The Tandem deposition method and deposition from a composite target both with and without titanium sublimation, were used to prepare the films. A typical granular structure was observed, with grain size in the range 2-20 rim. X-ray diffraction and selected area diffraction showed an ?-Fe (bcc) type structure. Magnetic properties showed that by varying the deposition method and some of the sputtering parameters (sputtering rate, argon flow, film thickness and substrate temperature), it is possible to switch from a relativeIy magnetically hard sample ( Hc ˜ 700 Oe) to a soft sample ( Hc ˜ 20 Oe). A dramatic increase in H c has been observed at cryogenic temperatures. This result, along with the Mössbauer data, suggests a shell/core granule morphology with an Fe and/or (Fe-Si) core surrounded by Fe-Si-O.

Christodoulides, J. A.; Shevchenko, N. B.; Hadjipanayis, G. C.; Papaefthymiou, V.

1997-02-01

419

Evaluation of the potential for hysteresis in index-velocity ratings for the Chicago Sanitary and Ship Canal near Lemont, Illinois  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) is responsible for monitoring flows in the Chicago Sanitary and Ship Canal (CSSC) near Lemont, Illinois, as a part of the Lake Michigan Diversion Accounting overseen by the U.S. Army Corps of Engineers, Chicago District. Lake Michigan Diversion Accounting is mandated by a U.S. Supreme Court decree in order to monitor, and limit, the State of Illinois’ annual diversion of Great Lakes water through the manmade CSSC. Every 5 years, a technical review committee consisting of practicing engineers and academics reviews USGS streamgaging practices in the CSSC near Lemont, Illinois. The sixth technical review committee expressed concern that the index-velocity rating—the method used to estimate mean cross-sectional velocity from a measured index velocity—may be subject to hysteresis at this site because of the unique, unsteady hydraulics of the canal. Hysteresis in index-velocity ratings can occur at sites where the flow distribution in the channel varies significantly between the rising and falling limbs of the hydrograph for the same discharge. Presently, hysteresis in index-velocity ratings has been documented only in tidally affected sites. This report investigates whether hysteresis can occur at this nontidal site, and the conditions under which it is likely to occur, by using both a theoretical approach and a three-dimensional hydrodynamic model. The theoretical analysis investigated the conditions required for hysteresis in the index-velocity rating, and the modeling analysis focused on the effect of the timing of the inflows from the CSSC and the Cal-Sag Channel on the potential for hysteresis and whether highly resolved simulations of actual high-flow events show any evidence of hysteresis. Based on both a theoretical analysis using observed historical data and an analysis using a three-dimensional hydrodynamic model, there is no conclusive evidence for the existence of hysteresis in the index-velocity rating at the USGS streamgage on the CSSC near Lemont, Illinois. Although the theoretical analysis indicated the possibility of hysteresis at this site, the hydrodynamic conditions required to generate hysteresis are not present at this site based on historical data. Ongoing streamgaging practices at this site will use the information in this report and include periodic assessment of the index-velocity rating for any signs of hysteresis that might result from future changes to the operation of this manmade canal.

Jackson, P. Ryan; Sinha, Sumit; Dutta, Som; Johnson, Kevin K.; Duncker, James J.; Garcia, Marcelo H.

2013-01-01

420

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

SciTech Connect

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

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

2012-01-01

421

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

422

Wideband and hysteresis-free regulation of piezoelectric actuator based on induced current for high-speed scanning probe microscopy  

SciTech Connect

A novel closed-loop regulation of a piezoelectric actuator is presented to implement wideband and hysteresis-free motion required for high-speed operation of scanning probe microscopy. Velocity of the actuator's displacement detected via the induced current and its integration giving the displacement were used to actively compensate the resonances and hysteresis. The validity of the idea was demonstrated using a prototype circuit composed of operational amplifiers and multilayered piezoelectric actuators. The fundamental resonance of the actuator at 260 kHz was completely eliminated from the actuator's displacement with an appropriate velocity feedback. With an additional displacement feedback the gain error was suppressed within {+-}5 dB over a frequency range from dc to 1 MHz, while a -45 deg. bandwidth was also maintained as wide as 250 kHz. In addition, intrinsic hysteresis of the actuator measured with an 8 kHz sinusoidal signal was suppressed to below 1%. Responses in displacement of the actuator to burst oscillation and square wave inputs exhibited clear improvement from the uncompensated responses.

Kageshima, Masami; Togo, Shinsuke; Li Yan Jun; Naitoh, Yoshitaka; Sugawara, Yasuhiro [Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan) and CREST, Japan Science and Technology Agency, Kawaguchi Center Bldg., 4-1-8, Honcho, Kawaguchi, Saitama 332-0012 (Japan); Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan) and CREST, Japan Science and Technology Agency, Kawaguchi Center Bldg., 4-1-8, Honcho, Kawaguchi, Saitama 332-0012 (Japan)

2006-10-15

423

Field test of a paradigm: hysteresis of heart rate in thermoregulation by a free-ranging lizard (Pogona barbata).  

PubMed

The discovery that changes in heart rate and blood flow allow some reptiles to heat faster than they cool has become a central paradigm in our understanding of reptilian thermoregulation. However, this hysteresis in heart rate has been demonstrated only in simplistic laboratory heating and cooling trials, leaving its functional significance in free-ranging animals unproven. To test the validity of this paradigm, we measured heart rate and body temperature (Tb) in undisturbed, free-ranging bearded dragons (Pogona barbata), the species in which this phenomenon was first described. Our field data confirmed the paradigm and we found that heart rate during heating usually exceeded heart rate during cooling at any Tb. Importantly, however, we discovered that heart rate was proportionally faster in cool lizards whose Tb was still well below the 'preferred Tb range' compared to lizards whose Tb was already close to it. Similarly, heart rate during cooling was proportionally slower the warmer the lizard and the greater its cooling potential compared to lizards whose Tb was already near minimum operative temperature. Further, we predicted that, if heart rate hysteresis has functional significance, a 'reverse hysteresis' pattern should be observable when lizards risked overheating. This was indeed the case and, during heating on those occasions when Tb reached very high levels (> 40 degrees C), heart rate was significantly lower than heart rate during the immediately following cooling phase. These results demonstrate that physiological control of thermoregulation in reptiles is more complex than has been previously recognized. PMID:10418165

Grigg, G C; Seebacher, F

1999-06-22

424

Field test of a paradigm: hysteresis of heart rate in thermoregulation by a free-ranging lizard (Pogona barbata).  

PubMed Central

The discovery that changes in heart rate and blood flow allow some reptiles to heat faster than they cool has become a central paradigm in our understanding of reptilian thermoregulation. However, this hysteresis in heart rate has been demonstrated only in simplistic laboratory heating and cooling trials, leaving its functional significance in free-ranging animals unproven. To test the validity of this paradigm, we measured heart rate and body temperature (Tb) in undisturbed, free-ranging bearded dragons (Pogona barbata), the species in which this phenomenon was first described. Our field data confirmed the paradigm and we found that heart rate during heating usually exceeded heart rate during cooling at any Tb. Importantly, however, we discovered that heart rate was proportionally faster in cool lizards whose Tb was still well below the 'preferred Tb range' compared to lizards whose Tb was already close to it. Similarly, heart rate during cooling was proportionally slower the warmer the lizard and the greater its cooling potential compared to lizards whose Tb was already near minimum operative temperature. Further, we predicted that, if heart rate hysteresis has functional significance, a 'reverse hysteresis' pattern should be observable when lizards risked overheating. This was indeed the case and, during heating on those occasions when Tb reached very high levels (> 40 degrees C), heart rate was significantly lower than heart rate during the immediately following cooling phase. These results demonstrate that physiological control of thermoregulation in reptiles is more complex than has been previously recognized. PMID:10418165

Grigg, G C; Seebacher, F

1999-01-01

425

Scaling Behavior of Ferroelectric Hysteresis Loop in 63PbTiO3–37BiScO3 Bulk Ceramic  

Microsoft Academic Search

The ferroelectric hysteresis loops of 63PbTiO3–37BiScO3 bulk ceramics were measured under sinusoidal electric fields over a frequency range of 1 Hz–100 Hz and amplitude range of 10 kV\\/cm–50 kV\\/cm. Scaling relation of ferroelectric hysteresis loops area ?A? versus frequency f and the amplitude of field E0 for the saturated loops is , while the scaling relation for the unsaturated loops

Gang Yu; Xuefeng Chen; Genshui Wang; Xianlin Dong

2010-01-01

426

Interaction of bipolaron with the H2O/O2 redox couple causes current hysteresis in organic thin-film transistors  

NASA Astrophysics Data System (ADS)

Hysteresis in the current-voltage characteristics is one of the major obstacles to the implementation of organic thin-film transistors in large-area integrated circuits. The hysteresis has been correlated either extrinsically to various charge-trapping/transfer mechanisms arising from gate dielectrics or surrounding ambience or intrinsically to the polaron-bipolaron reaction in low-mobility conjugated polymer thin-film transistors. However, a comprehensive understanding essential for developing viable solutions to eliminate hysteresis is yet to be established. By embedding carbon nanotubes in the polymer-based conduction channel of various lengths, here we show that the bipolaron formation/recombination combined with the H2O/O2 electrochemical reaction is responsible for the hysteresis in organic thin-film transistors. The bipolaron-induced hysteresis is a thermally activated process with an apparent activation energy of 0.29?eV for the bipolaron dissociation. This finding leads to a hysteresis model that is generally valid for thin-film transistors with both band transport and hopping conduction in semiconducting thin films.

Qu, Minni; Li, Hui; Liu, Ran; Zhang, Shi-Li; Qiu, Zhi-Jun

2014-01-01

427

Interaction of bipolaron with the H2O/O2 redox couple causes current hysteresis in organic thin-film transistors.  

PubMed

Hysteresis in the current-voltage characteristics is one of the major obstacles to the implementation of organic thin-film transistors in large-area integrated circuits. The hysteresis has been correlated either extrinsically to various charge-trapping/transfer mechanisms arising from gate dielectrics or surrounding ambience or intrinsically to the polaron-bipolaron reaction in low-mobility conjugated polymer thin-film transistors. However, a comprehensive understanding essential for developing viable solutions to eliminate hysteresis is yet to be established. By embedding carbon nanotubes in the polymer-based conduction channel of various lengths, here we show that the bipolaron formation/recombination combined with the H2O/O2 electrochemical reaction is responsible for the hysteresis in organic thin-film transistors. The bipolaron-induced hysteresis is a thermally activated process with an apparent activation energy of 0.29?eV for the bipolaron dissociation. This finding leads to a hysteresis model that is generally valid for thin-film transistors with both band transport and hopping conduction in semiconducting thin films. PMID:24463853

Qu, Minni; Li, Hui; Liu, Ran; Zhang, Shi-Li; Qiu, Zhi-Jun

2014-01-01

428

Pattern selection and hysteresis in the Rietkerk model for banded vegetation in semi-arid environments.  

PubMed

Banded vegetation is a characteristic feature of semi-arid environments. It occurs on gentle slopes, with alternating stripes of vegetation and bare ground running parallel to the contours. A number of mathematical models have been proposed to investigate the mechanisms underlying these patterns, and how they might be affected by changes in environmental conditions. One of the most widely used models is due to Rietkerk and co-workers, and is based on a water redistribution hypothesis, with the key feedback being that the rate of rainwater infiltration into the soil is an increasing function of plant biomass. Here, for the first time, we present a detailed study of the existence and stability of pattern solutions of the Rietkerk model on slopes, using the software package wavetrain (www.ma.hw.ac.uk/wavetrain). Specifically, we calculate the region of the rainfall-migration speed parameter plane in which patterns exist, and the sub-region in which these patterns are stable as solutions of the model partial differential equations. We then perform a detailed simulation-based study of the way in which patterns evolve when the rainfall parameter is slowly varied. This reveals complex behaviour, with sudden jumps in pattern wavelength, and hysteresis; we show that these jumps occur when the contours of constant pattern wavelength leave the parameter region giving stable patterns. Finally, we extend our results to the case in which a diffusion term for surface water is added to the model equations. The parameter regions for pattern existence and stability are relatively insensitive to small or moderate levels of surface water diffusion, but larger diffusion coefficients significantly change the subdivision into stable and unstable patterns. PMID:25142517

Dagbovie, Ayawoa S; Sherratt, Jonathan A

2014-10-01

429

Hysteresis, phase transitions, and dangerous transients in electrical power distribution systems.  

PubMed

The majority of dynamical studies in power systems focus on the high-voltage transmission grids where models consider large generators interacting with crude aggregations of individual small loads. However, new phenomena have been observed indicating that the spatial distribution of collective, nonlinear contribution of these small loads in the low-voltage distribution grid is crucial to the outcome of these dynamical transients. To elucidate the phenomenon, we study the dynamics of voltage and power flows in a spatially extended distribution feeder (circuit) connecting many asynchronous induction motors and discover that this relatively simple 1+1 (space+time) dimensional system exhibits a plethora of nontrivial spatiotemporal effects, some of which may be dangerous for power system stability. Long-range motor-motor interactions mediated by circuit voltage and electrical power flows result in coexistence and segregation of spatially extended phases defined by individual motor states, a "normal" state where the motors' mechanical (rotation) frequency is slightly smaller than the nominal frequency of the basic ac flows and a "stalled" state where the mechanical frequency is small. Transitions between the two states can be initiated by a perturbation of the voltage or base frequency at the head of the distribution feeder. Such behavior is typical of first-order phase transitions in physics, and this 1+1 dimensional model shows many other properties of a first-order phase transition with the spatial distribution of the motors' mechanical frequency playing the role of the order parameter. In particular, we observe (a) propagation of the phase-transition front with the constant speed (in very long feeders) and (b) hysteresis in transitions between the normal and stalled (or partially stalled) phases. PMID:23848724

Duclut, Charlie; Backhaus, Scott; Chertkov, Michael

2013-06-01

430

Neutron Monitor Observations and Hysteresis Phenomenon, 5. Results For Solar Minimum 1994-1996.  

NASA Astrophysics Data System (ADS)

On the basis of NM data on stations with different cut-off rigidities we found rigid- ity dependence of galactic cosmic ray long-term variation near the last solar mini- mum (sunspot numbers Wc40, period January 1994-January 1997). In the frame of the model of global cosmic ray modulation in the Heliosphere with taking into ac- count time-lag of processes in the interplanetary space relative to processes on the Sun by using data on solar activity-cosmic ray hysteresis effects, we determine the dimension of modulation region, radial diffusion coefficient, cosmic ray intensity out of the Heliosphere, and residual cosmic ray modulation in dependence of primary cos- mic ray particle rigidity with taking into account drift effects according to Burger and Potgieter (1999). We include in the consideration drift effects (as depending from the sign of solar polar magnetic field and determined by difference of total CR modulation at A>0 and A<0, and with amplitude dependent from the value of tilt angle between interplanetary neutral current sheet and equatorial plane). The amplitude of drifts in dependence of CR particle rigidity we use what was obtained in Dorman et al. (2002) from comparison of CR modulation in odd and even solar cycles. We estimate the dimension of modulation region (with taking into account the influence of nonlinear processes on the solar wind speed in the outer Heliosphere according to Le Roux and Fichtner, 1997), the radial diffusion coefficient and transport path in radial direction as well as residual CR modulation in the minimum of solar activity in dependence of primary CR particle rigidity. We discuss these results in connection with obtained in Dorman et al. (2002). REFERENCES: Burger, R. A., and M. S. Potgieter, Proc. 26th Inter. Cosmic Ray Conf., 7, 13, 1999. Dorman, L.I., et al., Report on ST19.02 Session of EGS-2002 Gen. Assembly. Le Roux, J. A. and H. Fichtner, Ap. J, 477, L115, 1997.

Dorman, L. I.; Iucci, N.; Parisi, . M.; Villoresi, G.

431

Hysteresis and precession of a swirling jet normal to a wall  

NASA Astrophysics Data System (ADS)

Interaction of a swirling jet with a no-slip surface has striking features of fundamental and practical interest. Different flow states and transitions among them occur at the same conditions in combustors, vortex tubes, and tornadoes. The jet axis can undergo precession and bending in combustors; this precession enhances large-scale mixing and reduces emissions of NOx. To explore the mechanisms of these phenomena, we address conically similar swirling jets normal to a wall. In addition to the Serrin model of tornadolike flows, a new model is developed where the flow is singularity free on the axis. New analytical and numerical solutions of the Navier Stokes equations explain occurrence of multiple states and show that hysteresis is a common feature of wall-normal vortices or swirling jets no matter where sources of motion are located. Then we study the jet stability with the aid of a new approach accounting for deceleration and nonparallelism of the base flow. An appropriate transformation of variables reduces the stability problem for this strongly nonparallel flow to a set of ordinary differential equations. A particular flow whose stability is studied in detail is a half-line vortex normal to a rigid plane—a model of a tornado and of a swirling jet issuing from a nozzle in a combustor. Helical counter-rotating disturbances appear to be first growing as Reynolds number increases. Disturbance frequency changes its sign along the neutral curve while the wave number remains positive. Short disturbance waves propagate downstream and long waves propagate upstream. This helical instability causes bending of the vortex axis and its precession—the effects observed in technological flows and in tornadoes.

Shtern, V.; Mi, J.

2004-01-01

432

Temperature Response of Soil Respiration in a Chinese Pine Plantation: Hysteresis and Seasonal vs. Diel Q10  

PubMed Central

Although the temperature response of soil respiration (Rs) has been studied extensively, several issues remain unresolved, including hysteresis in the Rs–temperature relationship and differences in the long- vs. short-term Rs sensitivity to temperature. Progress on these issues will contribute to reduced uncertainties in carbon cycle modeling. We monitored soil CO2 efflux with an automated chamber system in a Pinus tabulaeformis plantation near Beijing throughout 2011. Soil temperature at 10-cm depth (Ts) exerted a strong control over Rs, with the annual temperature sensitivity (Q10) and basal rate at 10°C (Rs10) being 2.76 and 1.40 µmol m?2 s?1, respectively. Both Rs and short-term (i.e., daily) estimates of Rs10 showed pronounced seasonal hysteresis with respect to Ts, with the efflux in the second half of the year being larger than that early in the season for a given temperature. The hysteresis may be associated with the confounding effects of microbial population dynamics and/or litter input. As a result, all of the applied regression models failed to yield unbiased estimates of Rs over the entire annual cycle. Lags between Rs and Ts were observed at the diel scale in the early and late growing season, but not in summer. The seasonality in these lags may be due to the use of a single Ts measurement depth, which failed to represent seasonal changes in the depth of CO2 production. Daily estimates of Q10 averaged 2.04, smaller than the value obtained from the seasonal relationship. In addition, daily Q10 decreased with increasing Ts, which may contribute feedback to the climate system under global warming scenarios. The use of a fixed, universal Q10 is considered adequate when modeling annual carbon budgets across large spatial extents. In contrast, a seasonally-varying, environmentally-controlled Q10 should be used when short-term accuracy is required. PMID:23469089

Jia, Xin; Zha, Tianshan; Wu, Bin; Zhang, Yuqing; Chen, Wenjing; Wang, Xiaoping; Yu, Haiqun; He, Guimei

2013-01-01

433

The role of hysteresis in modeling root water uptake, both for single root and root system models.  

NASA Astrophysics Data System (ADS)

The water retention curve obtained by progressive extraction of water from an initially saturated soil (desorption) differs from that obtained by gradual addition of water to air-dry soil (absorption). This phenomenon is called hysteresis (Koorevaar et al., 1983). Common as its occurrence is, it is often neglected in the modeling of root water uptake. We will present here a model for the transport of water to a single root. The model solves Richard's equation in cylindrical coordinates where the water uptake rate is a function of the root water potential. The occurrence of hysteresis is accounted for by application of the modified dependent domain model developed by Mualem (1984) and used by Kool and Parker (1987). We will discuss the differences in results due to the inclusion of the hysteresis subroutine, when alternate wetting and drying cycles occur. The influence of soil type and transpiration reduction function will be discussed. The findings obtained for the single root model were used to upscale root water uptake to a root system. This is a part of the FUSSIM2 model of Heinen and de Willigen (1998) and Heinen (2001), where water transport in a soil profile is calculated. We will use an example for a soil profile where the root length density decreases exponentially with depth, and where again wetting and drying cycles alternate. References Heinen M., 2001. FUSSIM2: brief description of the simulation model and application to fertigation scenarios. Agronomie 21: 285-296. Heinen, M., and P. de Willigen, 1998. FUSSIM2 A two-dimensional simulation model for water flow, solute transport and root uptake of water and nutrients in partly unsaturated porous media, QASA No. 20, AB-DLO, Wageningen, The Netherlands, 140 p. Kool J.B. and J.C. Parker, 1987. Development and evaluation of closed form expressions for hysteretic soil hydraulic properties. Water Resour. Res. 23: 105 114. Koorevaar P., G. Menelik and C. Dirksen, 1983. Elements of soil physics. Elsevier, Amsterdam, The Netherlands, Developments in Soil Science 13, 228 p. Mualem Y., 1984. A modified dependent domain theory of hysteresis. Soil Sci. 137: 283 291.

de Willigen, P.; Heinen, M.

2009-04-01

434

Observation of threshold energy and hysteresis in high current ion beam guiding and transmission through a micro-glass-capillary  

NASA Astrophysics Data System (ADS)

The energy dependent guiding of high current density (0.1-3 A/m2) argon ion beams through a micro-glass-capillary is studied. It is observed that ion transmission through the capillary takes place only if its energy is greater than the retarding potential barrier, which depends upon the amount of charge deposited on the capillary inner wall. Foremost evidence of the observation that the transmitted current exhibits hysteresis with ion energy is presented. Particle in cell simulations carried out by solving Poisson's and Newton's force equation self-consistently, agree reasonably well with the experimental results.

Paul, Samit; Jayakiran, A.; Bhattacharjee, Sudeep

2012-11-01

435

Room temperature resistive state switching with hysteresis in GdMnO3 thin film with low threshold voltage  

NASA Astrophysics Data System (ADS)

In this paper, we report a room temperature resistive state switching with hysteresis, in a thin film of GdMnO3 grown on NdGaO3 substrate. The switched states have a resistance ratio ?103. The switching is unipolar in nature, with a low set voltage <3 V, while the reset voltage <0.3 V. The switching occurs between a high resistance polaronic insulating state and a low resistance metallic state. The resistance state transition has been ascribed to an electronic mechanism that originates from co-existing phases (created by charge disproportionation) that can undergo a percolative transition enabled by the applied bias.

Nath, Rajib; Raychaudhuri, A. K.; Mukovskii, Ya. M.; Andreev, N.; Chichkov, Vladimir

2014-05-01

436

Large thermal hysteresis for iron(II) spin crossover complexes with N-(pyrid-4-yl)isonicotinamide.  

PubMed

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

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

2014-11-01

437

Note: Position self-sensing for piezoelectric actuators in the presence of creep and rate-dependent hysteresis  

NASA Astrophysics Data System (ADS)

Sensorless position signal can be obtained from the charge inflow to the piezoelectric actuator or effective capacitance variation due to stroke. However, the first technique imposes sophisticated hardware requirement and it is prone to drift due to current offset. The latter is limited to slow operations. In this note, a hybrid position observer is used to fuse these two self-sensing signals to obtain a high quality position signal which compensates for both creep (slow operations) and rate-dependent hysteresis (fast operations). Experimental results are presented to demonstrate the performance of the observer.

Islam, M. N.; Seethaler, R. J.

2012-11-01

438

Observation of threshold energy and hysteresis in high current ion beam guiding and transmission through a micro-glass-capillary  

SciTech Connect

The energy dependent guiding of high current density (0.1-3 A/m{sup 2}) argon ion beams through a micro-glass-capillary is studied. It is observed that ion transmission through the capillary takes place only if its energy is greater than the retarding potential barrier, which depends upon the amount of charge deposited on the capillary inner wall. Foremost evidence of the observation that the transmitted current exhibits hysteresis with ion energy is presented. Particle in cell simulations carried out by solving Poisson's and Newton's force equation self-consistently, agree reasonably well with the experimental results.

Paul, Samit; Jayakiran, A.; Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur, Uttar Pradesh 208016 (India)

2012-11-26

439

Enhancement of coil--stretch hysteresis by self-concentration in extensional flows, and its implications for capillary thinning of liquid bridges of dilute polymer solutions  

E-print Network

The coil-stretch transition in extensional flows of viscoelastic dilute polymer solutions is known to be associated with a strong hysteresis in molecular conformations and rheo-optical properties. At infinite dilution, hysteresis is caused by the large difference in frictional drag coefficient between undeformed isotropic polymer coils and highly stretched conformations. At the low extension rates in the hysteresis regime, stretched molecules pervade larger volumes than equilibrium coils since the flow is too weak to suppress transverse fluctuations. The onset of intermolecular overlap occurs for such stretched conformations at polymer concentrations much smaller than c*, the conventional critical overlap concentration for equilibrium coils. Therefore, for a range of concentrations c coefficient can grow strongly with concentration in the dilute regime. A dumbbell model with conformation-dependent drag model is used to predict a concomitant strong enhancement of coil-stretch hysteresis with increasing concentration in the dilute regime. This extensional flow induced self-concentration leads to a maximum in hysteretic effects around c*, which progressively diminish in the semi-dilute regime where screening in isotropic coils reduces the difference in drag coefficient between stretched and coiled states. It is shown that the concentration dependence observed by Clasen et al. (2006) of capillary-thinning dynamics in liquid bridges of polymer solutions provides direct evidence of coil-stretch hysteresis enhancement by self-concentration.

Ranganathan Prabhakar

2014-04-27

440

Purification and partial characterization of thermal hysteresis proteins from overwintering larvae of pine needle gall midge, Thecodiplosis japonensis (Diptera: cecidomiidae).  

PubMed

The pine needle gall midge of Thecodiplosis japonensis is a serious forest pest and overwinters as a 3rd instar larva at soil surface in Korea. The time necessary for killing 50% of larvae at -15 degree C is 160 min. During overwintering period, T. japonensis larvae accumulate relatively high content of trehalose as the main cryoprotectant. In this paper, the proteinaceous cryoprotectants were identified. Two thermal hysteresis proteins (THP-1S and 2S) were purified from overwintering larvae by ethanol fractionation, trichloroacetic acid precipitation, ion-exchange chromatography (DEAE-Sephadex A-25) and gel permeation chromatography (Sephadex G-100). Their molecular weights are 34.9 and 37.8 kD respectively. T. japonensis THPs cannot be stained by periodic acid-Schiffs' reagent, suggesting no carbohydrate in them. The thermal hysteresis activity of THP-2 at the concentration of 50 mg/ml is 11.02 +/- 0.08 degree C (mean +/- SD, n=10), perhaps the highest active insect THP. It is the first report of purified T. japonensis THPs in Diptera. PMID:12148056

Li, Y; Gong, H; Park, H Y

2000-01-01

441

In vivo evaluation of the skin tensile strength by the suction method: pilot study coping with hysteresis and creep extension.  

PubMed

From an engineering standpoint, both the skin and subcutaneous tissue act as interconnected load-transmitting structures. They are subject to a variety of intrinsic and environmental influences. Changes in the cutaneous viscoelasticity represent an important aspect in a series of skin conditions. The aim of this work was to explore the methodology of biomechanical measurements in order to better appreciate the evolution and severity of some connective tissue diseases. The Cutometer MPA 580 (C+K electronic) was used in the steep and progressive suction procedures. Adapting measurement modalities was explored in order to mitigate any variability in data collection. The repeat steep suction procedure conveniently reveals the creep phenomenon. By contrast, the progressive suction procedure highlights the hysteresis phenomenon. These viscoelastic characteristics are presently described using the 2 and 4?mm probes on normal skin and in scleroderma, acromegaly, corticosteroid-induced dermatoporosis, and Ehlers-Danlos syndrome. The apposition of an additional outer contention on the skin altered differently the manifestations of the creep extension and hysteresis among the tested skin conditions. Any change in the mechanical test procedure affects the data. In clinical and experimental settings, it is mandatory to adhere to a strict and controlled protocol. PMID:23986871

Piérard, Gérald E; Piérard, Sébastien; Delvenne, Philippe; Piérard-Franchimont, Claudine

2013-01-01

442

A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan beetle Upis ceramboides.  

PubMed

Thermal hysteresis (TH), a difference between the melting and freezing points of a solution that is indicative of the presence of large-molecular-mass antifreezes (e.g., antifreeze proteins), has been described in animals, plants, bacteria, and fungi. Although all previously described TH-producing biomolecules are proteins, most thermal hysteresis factors (THFs) have not yet been structurally characterized, and none have been characterized from a freeze-tolerant animal. We isolated a highly active THF from the freeze-tolerant beetle, Upis ceramboides, by means of ice affinity. Amino acid chromatographic analysis, polyacrylamide gel electrophoresis, UV-Vis spectrophotometry, and NMR spectroscopy indicated that the THF contained little or no protein, yet it produced 3.7 +/- 0.3 degrees C of TH at 5 mg/ml, comparable to that of the most active insect antifreeze proteins. Compositional and structural analyses indicated that this antifreeze contains a beta-mannopyranosyl-(1-->4) beta-xylopyranose backbone and a fatty acid component, although the lipid may not be covalently linked to the saccharide. Consistent with the proposed structure, treatment with endo-beta-(1-->4)xylanase ablated TH activity. This xylomannan is the first TH-producing antifreeze isolated from a freeze-tolerant animal and the first in a new class of highly active THFs that contain little or no protein. PMID:19934038

Walters, Kent R; Serianni, Anthony S; Sformo, Todd; Barnes, Brian M; Duman, John G

2009-12-01

443

Spatial Variations in Hysteresis Trend Between Seismic Noise and Hydrological Parameters During the small-to-large Typhoon Events  

NASA Astrophysics Data System (ADS)

Continuous seismic data recorded by seismometers near the river channel can reveal the energy induced by the river sediment transport. During the Typhoon seasons of 2011-2012, we deployed the seismic array (includes short-period and broadband sensors) along the river systems of southern Taiwan, which are relatively high variation of water discharge and high sediment supply. Firstly, we detected the landquake-induced seismic signal during Typhoon seasons and the locations of landquakes determined by a cross-correlation technique that maximizes the coherency of horizontal envelope function among seismic stations to preliminarily understand the situation of sediment supply. Then, we analyzed the relationship between the observed high-frequency (HF, 5-15 Hz) seismic noise levels and the regional meteorological and hydrological parameters (e.g. precipitation, water level, and discharge) recorded by the local weather stations and stream gauging stations. It is found that a hysteresis trend with HF seismic noise level is observed prior to the same hydrological parameters. The spatial variations in hysteresis trend that might suggest two possibilities: (1) the river seismic noise has distance-limitation for small Typhoon events, and/or (2) the spatial variation of river gradient significantly influences the seismic noise level. These observations demonstrate the feasibility of the fluvial seismology as a way to monitor bed load sediment transport over a Typhoon event, which can be regarded as an essential tool to help the hazard prevention.

Chao, Wei-An; Wu, Yih-Min; Chen, Chi-Hsuan

2014-05-01

444

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

NASA Astrophysics Data System (ADS)

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

Barnard, Daniel J.; Hsu, David K.

2011-06-01

445

A nonprotein thermal hysteresis-producing xylomannan antifreeze in the freeze-tolerant Alaskan beetle Upis ceramboides  

PubMed Central

Thermal hysteresis (TH), a difference between the melting and freezing points of a solution that is indicative of the presence of large-molecular-mass antifreezes (e.g., antifreeze proteins), has been described in animals, plants, bacteria, and fungi. Although all previously described TH-producing biomolecules are proteins, most thermal hysteresis factors (THFs) have not yet been structurally characterized, and none have been characterized from a freeze-tolerant animal. We isolated a highly active THF from the freeze-tolerant beetle, Upis ceramboides, by means of ice affinity. Amino acid chromatographic analysis, polyacrylamide gel electrophoresis, UV-Vis spectrophotometry, and NMR spectroscopy indicated that the THF contained little or no protein, yet it produced 3.7 ± 0.3 °C of TH at 5 mg/ml, comparable to that of the most active insect antifreeze proteins. Compositional and structural analyses indicated that this antifreeze contains a ?-mannopyranosyl-(1?4) ?-xylopyranose backbone and a fatty acid component, although the lipid may not be covalently linked to the saccharide. Consistent with the proposed structure, treatment with endo-?-(1?4)xylanase ablated TH activity. This xylomannan is the first TH-producing antifreeze isolated from a freeze-tolerant animal and the first in a new class of highly active THFs that contain little or no protein. PMID:19934038

Walters, Kent R.; Serianni, Anthony S.; Sformo, Todd; Barnes, Brian M.; Duman, John G.

2009-01-01

446

A simplified methodology to identify material parameters of a hyperelasto-visco-hysteresis model: application to a fluoro-elastomer  

NASA Astrophysics Data System (ADS)

This paper presents a method to identify material parameters of a hyperelasto-visco-hysteresis (HVH) model and its application for the simulation of a fluoro-elastomer behaviour. This 3D-phenomenological model is based on the additive decomposition of three stress components. Each of these constitutive stresses is related to a physical phenomenon that occurs during mechanical loading: a hyperelastic equilibrium stress response, an irreversible pure hysteresis stress contribution and a rate-dependent viscoelastic stress behaviour. In order to independently identify these parts of the model, an experimental campaign, including multi-step relaxation in traction and compression tests and simple relaxation in tension and compression tests, is used. The hysteretic and hyperelastic contributions are identified considering only the state at the end of the relaxation periods of the multi-step relaxation tests. The viscoelastic response is analytically calculated with the simple relaxation test. As an advantage, the developed identification scheme gives the possibility to discriminate all the stress components of the model. Finally, the numerical simulation of a seal in relaxation is carried out to verify the capability of the proposed HVH model by reproducing the mechanical response of the studied material.

Laurent, H.; Vandenbroucke, A.; Rio, G.; Aït Hocine, N.

2011-12-01

447

Computation of self-field hysteresis losses in conductors with helicoidal structure using a 2D finite element method  

NASA Astrophysics Data System (ADS)

It is well known that twisting current-carrying conductors helps to reduce their coupling losses. However, the impact of twisting on self-field hysteresis losses has not been as extensively investigated as that on the reduction of coupling losses. This is mostly because the reduction of coupling losses has been an important issue to tackle in the past, and it is not possible to consider twisting within the classical two-dimensional (2D) approaches for the computation of self-field hysteresis losses. Recently, numerical codes considering the effect of twisting in continuous symmetries have appeared. For general three-dimensional (3D) simulations, one issue is that no robust, widely accepted and easy to obtain model for expressing the relationship between the current density and the electric field is available. On the other hand, we can consider that in these helicoidal structures currents flow only along the helicoidal trajectories. This approach allows one to use the scalar power-law for superconductor resistivity and makes the eddy current approach to a solution of a hysteresis loss problem feasible. In this paper we use the finite element method to solve the eddy current model in helicoidal structures in 2D domains utilizing the helicoidal symmetry. The developed tool uses the full 3D geometry but allows discretization which takes advantage of the helicoidal symmetry to reduce the computational domain to a 2D one. We utilize in this tool the non-linear power law for modelling the resistivity in the superconducting regions and study how the self-field losses are influenced by the twisting of a 10-filament wire. Additionally, in the case of high aspect ratio tapes, we compare the results computed with the new tool and a one-dimensional program based on the integral equation method and developed for simulating single layer power cables made of ReBCO coated conductors. Finally, we discuss modelling issues and present open questions related to helicoidal structures and AC-loss computations in three dimensions.

Stenvall, A.; Siahrang, M.; Grilli, F.; Sirois, F.

2013-04-01

448

Double hysteresis loop induced by defect dipoles in ferroelectric Pb(Zr0.8Ti0.2)O3 thin films  

NASA Astrophysics Data System (ADS)

Pb(Zr0.8Ti0.2)O3 (PZT80/20) thin films were deposited on the Pt(111)/Ti/SiO2/Si(100) substrates by RF magnetron sputtering. Mainly perovskite crystalline phase with highly (202)-preferred orientation, determined by x-ray diffraction, was formed in the lead zirconate titanate (PZT)(80/20) thin films. Polarization measurements of the unannealed and aged films showed a clear double hysteresis loop. However, the double hysteresis loop phenomenon was greatly suppressed in the PZT thin films annealed under pure oxygen, and thus they exhibited larger remnant polarization (Pr = 6.3 ?C/cm2). The related mechanism for the appearance of constricted and double hysteresis loops was investigated to be associated with the realignment and disassociation of defect dipoles via oxygen octahedral rotations or oxygen vacancy diffusion. The butterfly-shaped C-V characteristic curve with a valley gave further evidence for double hysteresis loop characteristic in the unannealed and aged PZT thin films.

Pu, Yunti; Zhu, Jiliang; Zhu, Xiaohong; Luo, Yuansheng; Wang, Mingsong; Li, Xuhai; Liu, Jing; Zhu, Jianguo; Xiao, Dingquan

2011-02-01

449

Abstract: Present ferroelectric (FE) capacitor models mostly rely on continuous hysteresis loop characteristics of FE materials. Our experimental results show that this approach overestimates  

E-print Network

Abstract: Present ferroelectric (FE) capacitor models mostly rely on continuous hysteresis loop-model. The model mainly consists of two nonlinear capacitors, corresponding to the two different polarization states of an FE capacitor. I. INTRODUCTION Ferroelectric (FE) capacitors have long been recognized

Gulak, P. Glenn

450

Abstract: Present ferroelectric (FE) capacitor models mostly rely on continuous hysteresis loop characteristics of FE materials. Our experimental results show that this approach overestimates  

E-print Network

Abstract: Present ferroelectric (FE) capacitor models mostly rely on continuous hysteresis loop­model. The model mainly consists of two nonlinear capacitors, corresponding to the two different polarization states of an FE capacitor. I. INTRODUCTION Ferroelectric (FE) capacitors have long been recognized

Sheikholeslami, Ali

451

2432 IEEE TRANSACTIONS ON AUTOMATIC CONTROL, VOL. 45, NO. 12, DECEMBER 2000 Fig. 4. Signal w(t) acting as the output of backlash hysteresis.  

E-print Network

2432 IEEE TRANSACTIONS ON AUTOMATIC CONTROL, VOL. 45, NO. 12, DECEMBER 2000 Fig. 4. Signal w system. VI. CONCLUSION In this paper, a robust adaptive control architecture is proposed for a class. REFERENCES [1] N. J. Ahmad and F. Khorrami, "Adaptive control of systems with back- lash hysteresis

Krstic, Miroslav

452

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

PubMed

A setup for measuring the high-frequency hysteresis loops of magnetic samples is described. An alternating magnetic field in the range 6-100 kHz with amplitude up to 80 mT is produced by a Litz wire coil. The latter is air-cooled using a forced-air approach so no water flow is required to run the setup. High-frequency hysteresis loops are measured using a system of pick-up coils and numerical integration of signals. Reproducible measurements are obtained in the frequency range of 6-56 kHz. Measurement examples on ferrite cylinders and on iron oxide nanoparticle ferrofluids are shown. Comparison with other measurement methods of the hysteresis loop area (complex susceptibility, quasi-static hysteresis loops, and calorific measurements) is provided and shows the coherency of the results obtained with this setup. This setup is well adapted to the magnetic characterization of colloidal solutions of magnetic nanoparticles for magnetic hyperthermia applications. PMID:25273736

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

2014-09-01

453

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

E-print Network

on intercalated transition-metal dichalcogenide Fe0.25TaS2 in the polar Kerr geometry as a function of temperature report results of detailed magneto-optical Kerr effect (MOKE) spectroscopy measurements of ferromagPHYSICAL REVIEW B 84, 224402 (2011) Anomalous magneto-optical Kerr hysteresis loops in Fe0.25TaS2

Kono, Junichiro

454

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

SciTech Connect

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

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

2011-02-15

455

Role of the Bering Strait on the hysteresis of the ocean conveyor belt circulation and glacial climate stability  

PubMed Central

Abrupt climate transitions, known as Dansgaard-Oeschger and Heinrich events, occurred frequently during the last glacial period, specifically from 80–11 thousand years before present, but were nearly absent during interglacial periods and the early stages of glacial periods, when major ice-sheets were still forming. Here we show, with a fully coupled state-of-the-art climate model, that closing the Bering Strait and preventing its throughflow between the Pacific and Arctic Oceans during the glacial period can lead to the emergence of stronger hysteresis behavior of the ocean conveyor belt circulation to create conditions that are conducive to triggering abrupt climate transitions. Hence, it is argued that even for greenhouse warming, abrupt climate transitions similar to those in the last glacial time are unlikely to occur as the Bering Strait remains open. PMID:22493225

Hu, Aixue; Meehl, Gerald A.; Han, Weiqing; Timmermann, Axel; Otto-Bliesner, Bette; Liu, Zhengyu; Washington, Warren M.; Large, William; Abe-Ouchi, Ayako; Kimoto, Masahide; Lambeck, Kurt; Wu, Bingyi

2012-01-01

456

Ambipolar, low-voltage and low-hysteresis PbSe nanowire field-effect transistors by electrolyte gating.  

PubMed

Semiconductor nanowire field-effect transistors (FETs) are interesting for fundamental studies of charge transport as well as possible applications in electronics. Here, we report low-voltage, low-hysteresis and ambipolar PbSe nanowire FETs using electrolyte-gating with ionic liquids and ion gels. We obtain balanced hole and electron mobilities at gate voltages below 1 V. Due to the large effective capacitance of the ionic liquids and thus high charge carrier densities electrolyte-gated nanowire FETs are much less affected by external doping and traps than nanowire FETs with traditional dielectrics such as SiO2. The observed current-voltage characteristics and on/off ratios indicate almost completely transparent Schottky barriers and efficient ambipolar charge injection into a low band gap one-dimensional semiconductor. Finally, we explore the possibility of applying these ambipolar nanowire FETs in complementary inverters for printed electronics. PMID:23545580

Lokteva, Irina; Thiemann, Stefan; Gannott, Florentina; Zaumseil, Jana

2013-05-21

457

Measurement of Microwave Magnetic Hysteresis of Thin Film HTSC and Comparison with a Modified Critical State Model  

NASA Astrophysics Data System (ADS)

The hysteretic flux density B(H) of thin film HTSC resonators is measured through measurements of microwave surface impedance Z_s(H,T). A modified critical state model is examined to explain the data. The model generalizes Bean's original proposition by (i)including the demagnetization effects of perpendicular geometry which is commonly employed in experiments, (ii) including more than one critical currents as would be expected to exist in thin films and polycrystals, and (iii) generalizing the hysteresis law that is generally ascribed to this case. All this is done while still retaining the fundamental notions of a critical state. Our model shows good agreement with characteristic features of the data. Experimentally observed novel effects when the microwave and the DC fields are of comparable magnitude are also described. Implications of our experiment towards harmonic generation and intermods will also be presented.

Choudhury, Durga P.; Willemsen, Balam A.; Derov, John S.; Sridhar, S.

1997-03-01

458

Super-mercuryphobic and hydrophobic diamond surfaces with hierarchical structures: Vanishment of the contact angle hysteresis with mercury  

NASA Astrophysics Data System (ADS)

Increased roughness is known to enhance the natural wetting properties of surfaces, making them either more hydrophobic or more hydrophilic. In this work we study the wetting properties of water and mercury drops in contact with boron doped diamond films with progressively increased surface roughnesses. We show how thermal oxidation of a microcrystalline film creates pyramids decorated with sub-micron protrusions that turn its naturally mercuryphobic surface into super-mercuryphobic. With this liquid, we observe the vanishment of the contact angle hysteresis that is expected for rough surfaces as the contact angle approaches 180?, making small drops of mercury roll along out of the surface at an apparent zero tilt-angle. In contrast, the incorporation of nano-globules on the oxidized surface through a silanization process is necessary to increase the hydrophobic properties of the film for which the contact angle with water reaches 138°. The wetting states that dominate in each case are discussed.

Escobar, Juan V.; Garza, Cristina; Alonso, Juan Carlos; Castillo, Rolando

2013-05-01

459

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

460

Attenuation of systolic blood pressure and pulse transit time hysteresis during exercise and recovery in cardiovascular patients.  

PubMed

Pulse transit time (PTT) is a cardiovascular parameter of emerging interest due to its potential to estimate blood pressure (BP) continuously and without a cuff. Both linear and nonlinear equations have been used in the estimation of BP based on PTT. This study, however, demonstrates that there is a hysteresis phenomenon between BP and PTT during and after dynamic exercise. A total of 46 subjects including 16 healthy subjects, 13 subjects with one or more cardiovascular risk factors, and 17 patients with cardiovascular disease underwent graded exercise stress test. PTT was measured from electrocardiogram and photoplethysmogram of the left index finger of the subject, i.e., a pathway that includes predominately aorta, brachial, and radial arteries. The results of this study showed that, for the same systolic BP (SBP), PTT measured during exercise was significantly larger than PTT measured during recovery for all subject groups. This hysteresis was further quantified as both normalized area bounded by the SBP-PTT relationship (AreaN) and SBP difference at PTT during peak exercise plus 20 ms (?SBP20). Significant attenuation of both AreaN (p <; 0.05) and ?SBP20 (p <; 0.01) is observed in cardiovascular patients compared with healthy subjects, independent of resting BP. Since the SBP-PTT relationship are determined by the mechanical properties of arterial wall, which is predominately mediated by the sympathetic nervous system through altered vascular smooth muscle (VSM) tone during exercise, results of this study are consistent with the previous findings of autonomic nervous dysfunction in cardiovascular patients. We further conclude that VSM tone has a nonnegligible influence on the BP-PTT relationship and thus should be considered in the PTT-based BP estimation. PMID:24158470

Liu, Qing; Yan, Bryan P; Yu, Cheuk-Man; Zhang, Yuan-Ting; Poon, Carmen C Y

2014-02-01

461

Molecular origins of contact-angle hysteresis and other phenomena at aqueous interfaces of side-chain comb polymers  

NASA Astrophysics Data System (ADS)

The molecular-level origins of three separate phenomena associated with the polymer-water interface were investigated for certain side-chain comb polymers. Specifically, the following three phenomena were studied for polymeric surfaces in contact with water: (1) contact-angle hysteresis; (2) temperature dependence of wettability and thermal transitions; and (3) the resistance to nonspecific protein adsorption, or protein resistance. IR-visible sum-frequency-generation spectroscopy (SFS) was used as the main experimental technique in all three studies. SFS allows the in situ and selective probing of only the moieties at the polymer-water interface, and here it provides significant insights for the molecular origins of these interfacial phenomena. For 1, an alkyl-side-chain polymer, poly(vinyl n-octadecyl carbamate- co-vinyl acetate) (PVNODC), was used. SFS spectra indicate that in contact with water, the polymer surface is heterogeneous (having areas of differing surface energies). This evidence of surface heterogeneity supports the hysteresis observed in the advancing and receding contact angles of the polymer surface with water. For 2, the PVNODC-water interface was probed using SFS at above-ambient temperatures, and an order-to-disorder transition (ODT) of alkyl side chains at the interface was observed, which closely follows the melting of crystalline side chains in the bulk. This transition explains the increased wettability of the polymer, by water, when the temperature is raised above the bulk melting temperature. Finally, for 3, a comb polymer called POEC [random copolymer of methyl methacrylate, hydroxy-poly (oxyethylene) methacrylate, and poly (oxyethylene) methacrylate] having poly(oxyethylene) (POE) side chains of oligoineric dimensions was used. SFS spectra indicate that the POE CH2 groups at the air interface have an orientation distribution that is anisotropic, but in contact with water, the orientation distribution of these groups is isotropic. (Abstract shortened by UMI.)

Rangwalla, Hasnain

462

Pinus sylvestris L. needle surface wettability parameters as indicators of atmospheric environment pollution impacts: Novel contact angle hysteresis methodology  

NASA Astrophysics Data System (ADS)

An investigation of water contact angles (CAs), contact angle hysteresis (CAH) was carried out for 1-year to 4-year old needles (Pinus sylvestris) collected in urban (Gdansk) and rural (Karsin) locations using an original measuring technique based on the geometry of the drop on a vertical filament. Concentrations of air pollutants (SO2, NOx, C6H6, and suspended particular matter - SPM) currently considered to be most important in causing direct damage to vegetation were simultaneously monitored. A set of the surface wettability parameters: the apparent surface free energy ?SV, adhesive film tension ?, work of adhesion WA, and spreading WS, were determined from CAH data using the approach developed by Chibowski (2003) to quantify the surface energetics of the needle substrata affected by aging and pollution impacts. This formalism relates the total apparent surface free energy of the solid ?SV with only three measurable quantities: the surface tension of the probe liquid ?LV and its advancing ?A and receding ?R contact angle hysteresis. Since CAH depends on the outermost wax layer surface roughness and spatial physicochemical heterogeneity of a solid surface, CA data were corrected using surface architecture profiles registered with confocal scanning laser microscopy. It was found that the roughness parameter r is significantly negatively correlated (R = -0.74) with the needle age (collected at Karsin). The needle surface aging process resulted in its surface hydrophilization (CA? and CAH? with ?SV? and WA?). A temporal evolution of the needles wettability was traced with the data point distribution in the 2D space of CAH plotted versus WS. The wettability parameters were closely correlated to pollutant concentrations as evidenced from Spearman's rank correlation procedure (R = 0.63-0.91; p < 0.05). The aim of the study was to validate the established CA methodology to create a new non-invasive, low-cost technique suitable for monitoring of structural changes at interfaces of biological systems.

Pogorzelski, Stanis?aw J.; Rochowski, Pawel; Szurkowski, Janusz

2014-02-01

463

Testing for the presence and source of nonstationarity in United States energy efficiency: Time trends, hysteresis or random walk?  

NASA Astrophysics Data System (ADS)

This research tests for the presence and source of non-stationarity in U.S. aggregate energy efficiency for the 1900-1991 period. An outlier/intervention model is used to test for the presence of a unit-root in aggregate energy efficiency against the alternative hypothesis of a segmented/broken trend. A decomposed energy price model is also used to test if hysteresis in energy efficiency results from an asymmetrical response to energy price changes. The analysis revealed four distinct stages in aggregate energy efficiency during the 20th century: (1) the 1900-1920 period characterized by highly volatile decreases in energy efficiency caused by rapid industrialization and transition to a fossil-fueled economy; (2) the 1920-1949 period distinguished by a persistent increase in energy efficiency as the economy became adept at harnessing fossil energy; (3) the 1949-1972 period when energy efficiency remained stable within a narrow range; and (4) the 1973-1991 period when energy efficiency improved dramatically in response to the two oil prices shocks of the 1970s. Key modeling results include the following: (1) energy efficiency follows a unit-root process even when the effects of intervention outliers are taken into consideration, indicating that the unit-root hypothesis cannot be rejected against an alternative of a segmented/broken trend; (2) a major source of non-stationarity in energy efficiency is hysteresis induced by non-reverting changes in energy efficiency, in turn caused by dramatic increases in energy prices; and (3) although a strong negative trend appears to have occurred in aggregate energy intensity since 1920, it seems to be the result of energy price increases, rather than a general downward trend. An important economic implication of the analysis is that energy price increases appear to impact energy efficiency, while energy price decreases appear to have much less effect. This finding is consistent with much of the economic literature in this area that has indicated that energy efficiency and GDP growth respond asymmetrically to energy prices. Namely, energy efficiency and GDP growth respond to strong energy price increases, whereas large energy price decreases produce little reaction in these variables.

McArdle, Paul Francis

464

Effect of lattice defects and temperature transition rates on the deuteride (hydride) particle morphology and phase transformation thermal hysteresis in niobium  

NASA Astrophysics Data System (ADS)

Small-angle neutron scattering (SANS) measurements have been performed to investigate deuteride particle morphology and the phase transformation temperature hysteresis in low-concentration Nb-D alloys. Deformation either by cold rolling and or by previous deuteride cycling induced a coarse deuteride particle distribution. This observation is attributed to a more heterogeneous precipitation process facilitated by the dislocation defects and/or dislocation substructure. Deuteride precipitation in the deformed samples was observed immediately upon crossing the incoherent solvus during temperature reduction, again consistent with dislocation-aided nucleation. Deuteride dissolution was observed at the very onset of heating for the cold-rolled material, an observation unique among the samples characterized here. This is attributed to the availability of elastic accommodation energy for deuteride particles embedded in the severely work-hardened host matrix. In other words, the elastic energy assists dissolution, consistent with a theoretical model developed by Puls (1984 Acta Metall. 32 1259-69). The effect of temperature reduction transition rates was also investigated. Rapid, direct cooling (at 2-3 K min-1) resulted in a much finer deuteride particle distribution - a factor of 200 increase in the particle number density and a factor of ten reduction in characteristic particle size compared to well annealed single crystal Nb. The thermal hysteresis was also affected by the temperature transition rates, with a significant reduction of the hysteresis for the slowest cooling rates. This implies that at least part of the recorded hysteresis in the well annealed material is dependent on the temperature transition rate.

Heuser, Brent J.; Chen, W. C.

1999-09-01

465

Spin transition with a very large thermal hysteresis in a molecular crystal: an EPR study of Fe( PM-PEA) 2(NCS) 2  

Microsoft Academic Search

Magnetic susceptibility and X- and Q-band EPR studies are reported for the Fe2+ spin transition compound (Fe(PM-PEA)2(NCS)2) in powder form. An exceptionally large thermal hysteresis loop, about 60 K, has been found by both techniques. The EPR studies have been carried out on compound doped with Mn2+ (0.1‰ of Mn\\/Fe). An original EPR spectra simulation program has been elaborated in

Hervé Daubric; Christophe Cantin; Cyrille Thomas; Janis Kliava; Jean-François Létard; Olivier Kahn

1999-01-01

466