Exhibit Hysteresis Effects Research Articles

Performance of a Telescopic Dual-Tube Automotive Damper and the Implications for Vehicle Ride Prediction

This paper outlines a theoretical model of a dual-tube damper, presents the results of a digital simulation and compares them with previous experimental results. The damper characteristics are confirmed as being highly non-linear and exhibiting hysteresis effects. A prediction of the ride performance of a vehicle fitted with these dampers is made and shows that the typical linear and bilinear models of the damper are inappropriate and lead to over-optimistic estimates of ride performance.

Accommodative Hysteresis: Relation to Resting Focus

Seventeen subjects sustained focus for up to 8 min on targets placed either at the nearpoint (NP) or farpoint (FP) of accommodation. This was repeated in separate sessions from three to six times at each target distance and pre- to postexposure changes in dark focus (DF), i.e., accommodative hysteresis, were recorded. For eight subjects the probability (P) of exhibiting hysteresis effects was greater than or equal to 0.50 on both types of sessions. Five additional subjects showed P(NP) greater than or equal to 0.66 and P(FP) less than or equal to 0.33, whereas 4 subjects showed a reversed preference with P(NP) less than or equal to 0.17 and P(FP) greater than or equal to 0.83. Thus, strong individual differences emerged with respect to susceptibility to accommodative hysteresis. Linear regression analyses were performed on the individual data of the 13 subjects in condition NP and 12 in condition FP who exhibited hysteresis effects on greater than or equal to 50% of their sessions. Relative magnitudes of accommodative hysteresis resulting either from sustained NP or FP focusing were negatively related to the DF level measured directly before the period of sustained focus. Thus, for example, a relatively near initial DF correlated with a small inward shift of the DF after NP focusing, but with a large outward shift after FP focusing. Only in the FP condition was there evidence for a positive regression of hysteresis effects on the dioptric distance separating the sustained focus target and the initial DF level, viz., the less the separation, the smaller the hysteresis effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of random fields on the phase transitions and phase diagram ofMn0.75Zn0.25F2

The magnetic phase transitions and phase diagram of ${\mathrm{Mn}}_{0.75}$${\mathrm{Zn}}_{0.25}$${\mathrm{F}}_{2}$ are investigated by dilatometric, ultrasonic-attenuation, and magnetization measurements. The random fields, generated by the magnetic field $H$, affect all three phase boundaries: the spin-flop line ${H}_{\mathrm{sf}}(T)$ separating the antiferromagnetic (AF) phase from the spin-flop (SF) phase; the boundary ${T}_{c}^{\ensuremath{\parallel}}(H)$ between the paramagnetic (P) and AF phases; and the P-SF boundary ${T}_{c}^{\ensuremath{\perp}}(H)$. At $T=0$, ${H}_{\mathrm{sf}}=58.2\ifmmode\pm\else\textpm\fi{}0.3$ kOe. At high temperatures the boundary ${H}_{\mathrm{sf}}(T)$ is reentrant, in disagreement with the mean-field prediction. Near the P-AF transitions the differential thermal expansion and differential magnetostriction exhibit hysteresis effects when the transition field is above about 12 kOe. In low fields the P-AF transitions are quite sharp, in agreement with earlier data. In high fields the P-AF transitions are smeared if the sample is cooled at constant $H$ or if $H$ is reduced at constant $T$. The P-AF transitions at high $H$ are sharper if the sample is warmed in a field after it has been cooled in zero field. The hysteretic behavior at high $H$ is consistent with recent theory. The transition temperature ${T}_{c}^{\ensuremath{\parallel}}$ is depressed substantially by the random fields. The crossover exponent obtained from the low-field results for ${T}_{c}^{\ensuremath{\parallel}}$ is $\ensuremath{\varphi}=1.25\ifmmode\pm\else\textpm\fi{}0.07$, which agrees with the Fishman-Aharony prediction. The N\'eel temperature is 46.0 K. The P-SF transition temperature ${T}_{c}^{\ensuremath{\perp}}$ increases with increasing $H$ up to 131 kOe. This increase of ${T}_{c}^{\ensuremath{\perp}}$ is much larger than in pure Mn${\mathrm{F}}_{2}$, but is consistent with other data in siterandom uniaxial antiferromagnets. The phase diagram in the bicritical region is qualitatively different from that in pure Mn${\mathrm{F}}_{2}$. Also, we do not observe the two separate critical lines which surround the intermediate phase suggested by Aharony.

Microviscosity of dilute latex + gelatin dispersions determined by dynamic light-scattering

The microviscosity of dilute latex + gelatin dispersions has been studied by dynamic light-scattering at gelatin concentrations up to 1.0 wt % and temperatures in the range 8–45 °C. The change in mean particle diffusion coefficient following a rapid quench correlates strongly with the change in bulk shear viscosity of the gelatin solution. Slow thermal studies of latex + gelatin exhibit hysteresis effects which are mirrored by bulk viscometry data for gelatin solutions at the same concentration.