Hysteresis dynamic

To obtain the dynamic hysteresis loop of a ferroelectric capacitor the polarization is measured versus the applied voltage. Since the hysteresis is neither a linear nor a time invariant property, the hysteresis loop is dependent on the sample history and on the measurement method. To have a standardized and comparable hysteresis loop, certain parameters are commonly fixed. One is the absolute position of the loop on the polarization axis, since the initial (virgin) state of the polarization is unknown in almost all cases, the hysteresis loop is balanced to a reference value. Most commonly the positive and negative saturation polarization are set to... 

In Figure 3.12 a static hysteresis loop is shown in correlation to a dynamic hysteresis loop. Two clippings of the excitation signal of the static hysteresis loop are shown. Each of them is used to measure one data point of the curve. To record 20 points for one loop, 20 of these excitation signals have to be applied to the sample, each one stopping at a different voltage. 

Figure 15. Dynamic hysteresis-loop effects (a) magnetic viscosity and (b) sweep-rate dependence. The sweep-rate dependence amounts to a fluctuation-field [165] or sweep-rate correction to the static coercivity Hco.

Dynamic hysteresis is caused largely by the change of meniscus shape during a transition stage. Therefore, a hydrophobic surface shows the larger separation of the immersion line and the emersion line than a hydrophilic surface as seen in Figure 26.16, which depicts dynamic hysteresis for untreated, TMS-treated, and (TMS + 02)-treated polymer films. However, dynamic hysteresis is probably not maximal with TMS treatment. 

Figure 26.16 Effect of plasma treatment on dynamic hysteresis, which is the difference in the d5mamic first cycle advancing line and the receding line, (AF/L)d (mN/m) = (F/L)D,a,i — (F/T)D,r,i IS a direct result of the changing shape of the meniscus during a wetting cycle.

In general, dynamic hysteresis is smaller with smaller cross-sectional area because the effect of buoyancy is less. Thus, the dynamic hysteresis is not a measure of surface characteristics. Intrinsic hysteresis is a measure of the surface dynamic stability of the surface. 

One common nonlinear characteristic of control valves is hysteresis, which results in two possible flows at a given valve position, depending on whether the valve is opening or closing. In the steady-state, hysteresis limits resolution in achieving a specific flow with its desired effect on the process. Dynamically, hysteresis also creates pre-stoke deadtime, which contributes to total loop deadtime, thus degrading the performance of the loop. Pre-stroke deadtime is the time that elapses as the controller output slowly traverses across... 

Carrey J, Mehdaoui B, Respaud M. Simple models for dynamic hysteresis loop calculations of magnetic single-domain nanoparticles application to magnetic hyperthermia optimization. Journal of Applied Physics. 2011 109 083921(1)—083921 (17). DOI 10.1063/1.3551582. 

The dependence of the concentration of ionized groups (and consequently the water uptake) on the duration tgx of th immersion in the solution leads to an additional dynamical hysteresis in the sensor output characteristic which can be minimized by setting constant tgx for all pH measurements. 

The hysteresis phenomenon was analyzed in terms of two classes dynamic hysteresis containing a kinetic and an ohmic component, and stationary or thermodynamic hysteresis. It was concluded that the hysteresis in cyclic voltammograms observed for poly(3-methylthiophene) is mainly kinetic in nature, while for PANI the hysteresis (which is independent of scan rate and current) has a thermodynamic origin [224]. 

The nonlinear viscoelastic behavior of elastomers is usually related to their inner structure interaction, namely, the interaction between the matrix molecules, the interaction between the matrix molecules and fillers, and the interaction between the fillers. Of course, the effect of characteristics of the inner structure on the nonlinear viscoelastic behavior of elastomers cannot be ignored, since it is also related to portion of the energy dissipated during dynamic deformation. For instance, the filler parameters are important which influence the dynamic properties of rubber compounds, dynamic hysteresis in particular, as well as their temperature... 

The creep deformation behavior of TPU under static load can be determined by dynamic hysteresis measurements in reduced testing times without the risk of changing morphoiogy. 

Medium high ACN, higher unsaturation for lower dynamic hysteresis, sulfur or peroxide vulcanization... 

Medium high ACN, high level of unsaturation for low dynamic hysteresis in belts and dynamic applications, sulfur or peroxide vulcanization, lower viscosity for transfer and injection molding Higher ACN content for better hydrocarbon resistance, peroxide vulcanization High ACN for fuel applications, peroxide vulcanization... 

Note Optimization = 3 factor, 2,2 and 2-level full factmial design—8 compounds and experiments. Responses (properties) to be measured Dynamic hysteresis heat resistance, 1008 hat 120°C resistance to application fluids, 70 h at 120 C extrusion processing. 

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