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A rapid decrease in Jc with elevating temperature was recently observed in melt-processed Y-Ba-Cu-O at low temperatures. This suggests an existence of weak links in this material. In order to investigate weak link property in this material, the history effect of Jc and Jc in the longitudinal field geometry were measured. These measurements suggest that weak link property in this material is quite different from those at grain boundaries in polycrystalline materials.

The prediction of service lifetime and the selection of alloys for maximum fatigue crack growth resistance are made complicated by the effect of prior loading histories on the rate of crack growth. Some research indicatesthat crack closure can be an important factor in accounting for this history effect. This paper presents a review of the lifetime on load-interaction effects on fatigue crack growth and indicates some of the future research needed to better understand the factors giving rise to history effects in the growth of long and short cracks.

Creep fatigue interaction is one of the main failure modes for high temperature pressurized equipment. In practice, the amplitude of load on structure often changes which results in the load history effect on cyclic behavior and life of material. Therefore, 316L stainless steel 1-step and 2-step creep fatigue test under high temperature was conducted, the influence of two kinds of load history on material behavior was analyzed. The results showed the first step load with different amplitude and life fraction would lead to different hardness or softness of material and affect the cyclic behavior under the second step load. There is also much difference of material behavior at the time of load change for high-low and low-high load case. A uniform nonlinear creep fatigue damage model based on “disorder” and a modified failure rule coupled with the load history effect were presented in the paper. The creep fatigue life under 2-step load at high temperature was evaluated by the damage model and the modified rule. The predicted results were in good agreement with the experimental data.Copyright © 2009 by ASME

A study of spear fishing by the Bari of the Maracaibo Basin provides data demonstrating a benefit accruing to individual fishermen fishing in groups. An analysis of counts of successful and unsuccessful spear thrusts shows that fish are made more vulnerable to spear thrusts by companion fishermen who wear down and confuse the fish. Fish vulnerability is seen to depend on the number of encounters a fish has already survived. This Encounter History effect may be operative in other predator and prey relationships.

Critical current density and its history effect in Bi-based high Tc superconducting tapes were measured using an a.c. inductive method with various magnetic fields and temperatures. A rapid decrease in the critical current density with increasing temperature and the history effect were observed in the same low temperature region between 4.2 and 30 K. This suggests that the two phenomena are caused by low temperature weak links in the specimens. A weak link region is considered to lose superconductivity at temperatures higher than 30 K. Above 30 K, a strongly bonded area retains superconductivity and the Jc changes slowly with increasing temperature, showing no history effect.

Time/temperature integrators (TTI) have a potential for monitoring time-temperature history of perishable foods, including dairy products. To correlate the end of shelf life of dairy products with different TTI's, kinetic data for growth of a dairy spoilage microorganism was obtained. Both Arrhenius and square root equations were used to model the growth of Pseudomonas fragi. A significant negative history effect was observed for P. fragi growth rate whereas history effect was positive on the lag phase, under certain nonisothermal conditions. A correlation scheme of P. fragi growth was developed with the TTI response. The application of TTI's for dairy products is feasible despite the history effects.

Sea surface images obtained during the 2006 Marine Aerosol Production (MAP) campaign in the North East Atlantic were analysed for values of percentage whitecap coverage (K. Values of Ware presented for wind speeds Lip to circa 23 m s(.) (1). The W data were divided into two overlapping groups and a piecewise, wind-speed-only parameterization of W is proposed that is valid for wind speeds between 3.70 m s(.) (1) and 23.09 m s(.) (1). Segregation of data points based upon a 2.5 hour wind history acted to decrease data scatter at wind speeds above approximately 9.25 m s(.) (1). At these wind speeds W values were greater for decreasing wind speeds than for increasing wind speeds. No clear wind history effect was observed at wind speeds below 9.25 m s(.) (1). Citation: Callaghan, A., G. de Leeuw, L. Cohen, and C. D. O'Dowd (2008), Relationship of oceanic whitecap coverage to wind speed and wind history, Geophys. Res. Lett., 35, L23609, doi: 10.1029/2008GL036165.

Recently, a local stress based approach to fracture, developed by Hadidi-Moud et al [1] was applied to predict cleavage fracture probability in ferritic steels. Predictions were validated by experimental data from Smith et al [2] and Garwood and Smith [3]. The model captured the influence of warm pre-stressing on low temperature fracture by using distribution parameters calibrated to as received data, as shown by Hadidi-Moud et al [4]. This was justified by noting that the plastic zone stress field automatically contained the prior load history effect and thus accounted for its contribution to fracture.

Animals optimize behaviors by predicting future critical events based on histories of actions and their outcomes. When behavioral outcomes like reward and aversion are signaled by current external cues, actions are directed to acquire the reward and avoid the aversion. The basal ganglia are thought to be the brain locus for reward-based adaptive action planning and learning. To understand the role of striatum in coding outcomes of forthcoming behavioral responses, we addressed two specific questions. First, how are the histories of reward and aversion used for encoding forthcoming outcomes in the striatum during a series of instructed behavioral responses? Second, how are the behavioral responses and their instructed outcomes represented in the striatum? We recorded discharges of 163 presumed projection neurons in the striatum while monkeys performed a visually instructed lever-release task for reward, aversion, and sound outcomes, whose occurrences could be estimated by their histories. Before outcome instruction, discharge rates of a subset of neurons activated in this epoch showed positive or negative regression slopes with reward history (24/44), that is, to the number of trials since the last reward trial, which changed in parallel with reward probability of current trials. The history effect was also observed for the aversion outcome but in far fewer neurons (3/44). Once outcomes were instructed in the same task, neurons selectively encoded the outcomes before and after behavioral responses (reward, 46/70; aversion, 6/70; sound, 6/70). The history- and current instruction–based coding of forthcoming behavioral outcomes in the striatum might underlie outcome-oriented behavioral modulation.

The impact of silicon-on-insulator (SOI) history effect in communication circuits containing delay chains is experimentally evaluated. In previous work, SOI history has been seen to change data pulse widths by 5% to 15% for fixed data patterns. In contrast, this work shows that data scrambling and DC balance reduce the effect to 1% or less, eliminating history effect as a concern for such communication circuits.

The liquid thermal history effect on liquid supercooling behavior has been found in various metals and alloys; typically the degree of liquid supercooling (ΔT−) increases with the increase of liquid overheating (ΔT+) up to several to tens of degrees above the equilibrium melting point (T0). Here we report quantitative experimental measurements on the ΔT−-ΔT+ relationship of Al small particles encapsulated in Al2O3 shells by using a differential scanning calorimeter. We find a remarkable dependence of ΔT− on ΔT+ of Al small particles, extending to at least 340 °C above T0 of Al (~1.36T0), which indicates the existence of temperature-dependent crystallization centers in liquid Al up to very high liquid overheating levels. Our results demonstrate quantitatively the significant effect of liquid thermal history on the supercooling behavior of Al and its alloys, and raise new considerations about the dependence of ΔT− on ΔT+ at very high ΔT+ levels.

History effects in 65-nm partially-depleted Silicon-on-Insulator CMOS technology are systematically measured and characterized. The impact of various process adjustments on these effects is analyzed, and an optimization strategy is presented. Hardware data show >9% history effect changes is controllable with no loss of performance (e.g. speed and leakage), offering more flexibility in SOI circuit designs.

Understanding the mechanisms of protein folding is a major challenge that is being addressed effectively by collaboration between researchers in the physical and life sciences. Recently, it has become possible to mechanically unfold proteins by pulling on their two termini using local force probes such as the atomic force microscope. Here, we present data from experiments in which synthetic protein polymers designed to mimic naturally occurring polyproteins have been mechanically unfolded. For many years protein folding dynamics have been studied using chemical denaturation, and we therefore firstly discuss our mechanical unfolding data in the context of such experiments and show that the two unfolding mechanisms are not the same, at least for the proteins studied here. We also report unexpected observations that indicate a history effect in the observed unfolding forces of polymeric proteins and explain this in terms of the changing number of domains remaining to unfold and the increasing compliance of the lengthening unstructured polypeptide chain produced each time a domain unfolds.

History effect measurements on different circuits in a 150 nm SOI technology show no adverse impact on worst-case delay vs. leakage trade-offs. The performance advantage of SOI over bulk is shown to come mostly from capacitance reduction. Hence, it will diminish with technology scaling.

Single-ended complementary pass-transistor logic (CPL), also known as LEAP. has been a popular choice for implementing high-performance arithmetic operations due to its efficiency in device use. The circuit, however, is predicted to exhibit a large history effect when implemented in a partially depleted SOI (PD/SOI) technology. This paper presents direct measurement of its history effect in a 0.18/spl mu/m, 1.5V PD/SOI technology with L/sub eff/ = 0.08 /spl mu/m and t/sub ox/ = 2.3 nm.

In recent technologies, the aggressive scaling of the gate oxide thickness leads to significant increase in gate currents. In case of SOI technology, the gate-to-body component has to be considered carefully, since it strongly impacts the history effects In this paper, we study its effect on partially-depleted floating-body device. behaviour. Generation and recombination transients are analyzed by correlating drain current and body potential measurements performed on body contacted devices. Impact on history effect is also studied, considering not only first and second switches, but the complete simulation until steady-state.

Partially depleted SOI CMOS gates with floating body exhibit variable propagation delays because of the history effect. In this paper we address the problem of how to find the steady-state in a CMOS gate without resorting to huge computer resources. Moreover, a simple method for the evaluation of delay upper and lower bounds is described.

As partially depleted SOI technology becomes very attractive for ULSI CMOS, an in-depth characterization of floating body (FB) effects is required, especially for circuit design. One of the most important FB effects is the history effect, i.e. the propagation delay variation versus time. Many publications have shown experimental and simulation analysis of those effects. Most of the time, the experimental analysis of the history effect is done through chains, from which the propagation delay is extracted. In this paper, we propose a new structure that enables us to do an in-depth characterization of history effect, distinguishing between pull-up and pull-down delays for the first and second switches.

Recently discovered Hg-based oxide superconductors are found to be less anisotropic than Bi-based ones and expected to have superior irreversible properties. In order to investigate the irreversible property in this material, the critical current density and the irreversibility line in sintered bulk Hg-1212 specimens are measured. The history effect of the critical current density due to the weak link property between grains is observed. The obtained irreversibility field is compared with the results for other various superconductors and it is found that the irreversibility field is as low as that in Bi-2223 superconductors. This result indicates that the superconductivity in the sintered Hg-1212 is as strongly two-dimensional as Bi-2223.

In nondiapause adults raised under a long-day photoperiod, the critical daylength for diapause induction was between 13 and 14 h although some individuals did not respond to the short-day photoperiod and went on laying eggs. In postdiapause adults in which LD 13∶11 induced the first diapause (L13 insects), the critical daylength for diapause reinduction was between 13 and 14 h, whereas it was between 12 and 13 h in postdiapause adults in which LD 10∶14 induced the first diapause (L10 insects). Under LD 13∶11, a small proportion of L10 insects went into the second diapause after great delay as compared with L13 insects. Under LD 10∶14, on the other hand, L10 insects went into the second diapause more rapidly than L13 insects. Therefore, the photoperiod which had induced the first diapause affected the photoperiodic induction of the second diapause not only in the critical daylength but also in the speed of response. In Riptortus clavatus, the photoperiodic history influences the subsequent photoperiodic response even after a physiological state induced by the previous photoperiod was terminated completely.

Two kinds of YBaCuO bulk samples with different densities and sizes of 211 particles were prepared by the melt powder melt growth method. The magnetic field and temperature dependences of critical current density, J c, were measured inductively. Strong dependence of J c on size and density of 211 particles at higher temperatures was observed, while no relationship could be recognized between the two at lower temperatures. This result supports the expectation that nonsuperconducting particles such as the 211 phase act as dominant pinning centers at higher temperatures. A history effect was observed at 4.2 K, suggesting an existence of weak links.

Detailed results are presented of shear stress range variation during cycling of 1 per cent Cr-Mo-V test specimens within controlled total shear strain limits at 565°C. The cyclic softening induced during continuous and two-step cycling are compared. A saw-toothed pattern for the strain was maintained for each cycle giving a constant straining rate. Normal cyclic softening was found throughout the tests but another phenomenon of over-softening occurred during the two-step tests when high strain cycles took place first. A permanent history effect had been produced within the steel. This over-softening did not depend on the straining rate of the cycling or the magnitude of the initial cycle ratio. The generally accepted method of determining cyclic stress-strain curves using continuous cycling is shown to be invalid when over-softening is present.

Ilyushin's general plasticity theory expressed in a vector space corresponding to the deviatoric tensor space is available in formulating precise stress-strain relations of inelastic deformations by incorporating the deformation history of metals under complex loadings. In this case, the hypothesis of local determinability proposed by L ensky (1960) is useful for determining the explicit form of the stress-strain relation. In the present paper, the hypothesis is discussed by using not only data obtained by an experiment in which the history effect on the succeeding deformation is clearly estimated, but also data described in previous work. As the result, the hypothesis of local determinability has been confirmed to hold with high accuracy in every case.

The crystallization of isotactic polybutene-1 (PB-1) from dilute solutions was studied by Holland and Miller, who observed that the resulting crystal structure was dependent on the temperature of dissolution as well as the temperature of crystallization. Their study has been reexamined and further explored in detail under more general experimental conditions. The effect of using different crystal polymorphs as the starting material and that of keeping the solution for various lengths of time at selected temperatures before crystallization have been studied. The results generally agree with the previous findings of Holland and Miller and provide further information which suggests that PB-1 molecules assume definite helical conformations in solution. With time, the chains tend to transform from their original solid-state conformations to the one which is thermodynamically favored at the solution temperature.

Random point pinning of ideal or defective flux-line lattices is simulated on a computer. For weak pins, Larkin and Ovchinnikov's two-dimensional collective pinning is confirmed: ${j}_{c}=\mathrm{const}\ifmmode\times\else\texttimes\fi{}\frac{{n}_{p}〈{{f}_{p}}^{2}〉}{{R}_{p}{c}_{66}}$ (${j}_{c}$ is the critical current; ${n}_{p}$, ${f}_{p}$, and ${R}_{p}$ are the density, force, and range of pins; and ${c}_{66}$ is the shear modulus). The constant is determined. Defective lattices are pinned more strongly by factors 1.3 to 3, explaining the observed history effect. A pronounced jump in the curves ${j}_{c}({f}_{p})$ indicates the onset of plastic deformation.

Application of time temperature indicators (TTI) is based on response information or kinetic models from isothermal testing. The reliability of such models under variable temperature conditions was systematically studied. Nonisothermal experiments of two types were conducted involving prolonged exposures to high temperatures followed by storage at low temperatures to study the “history effect,” and storage at controlled, sinusoidaly varying temperatures. Three major types of commercial TTI were studied. Results showed that, although some types of TTI exhibit a significant “history effect,” the prediction models can be applied satisfactorily for the variable temperature storage.

Shock loading history effect on solid state response of iron meteorites to annealing at moderate temperatures permits deductions about thermal history

An experimental investigation was performed to evaluate the effect of strain history on an initially isotropic material. A hot-rolled 2.5-in.-diam bar of SAE 1045 steel provided all the test specimens. Axial and circumferential compression data indicated that the steel was isotropic. Additional tension and torsion data indicated that the steel was an isotropic-hardening von Mises material; this was also confirmed by proportionate loading of thin-walled cylinders such that the ratio of axial to circumferential stresses was either 0, 1/2, 1, 2 or ∞. Two additional sets of cylinders were preloaded either in simple axial tension or as closed-ended cylinders to an effective plastic strain of 0.006 before they were proportionately loaded. The preloading had a pronounced effect on yield surfaces for reloading if the effective plastic strain on reloading was only slightly greater than that for the preloading. The effect of preloading on the yield surfaces was small when the effective plastic strain was three to four times that for the preloading. Hill's anisotropic theory was used to predict stress-strain relations for several of the reloaded cylinders. Good agreement was obtained between theory and experiment.

Analyse du comportement des courbes contrainte-deformation cycliques dans des echantillons soumis a des essais de fatigue en traction-compression. Explication des resultats par le mouvement des dislocations

We investigate the evolution of heterogeneous stress states along frictional in- terfaces. Using finite-element simulations, we model the occurrence of precur- sory slip sequences on a deformable-deformable as well as a deformable-rigid interface between two solids. Every interface rupture creates a stress concen- tration at its arrest position and erases the stress concentrations produced by previous slip events. While the interface is sticking perfectly between two slip events, erased stress concentrations reappear and survive several cycles of ruptures. Such reestablished stress concentrations are smaller than they were before the rupture. We show that the decrease rate of these stress concentrations is exponential with respect to the number of subsequent events and that the bulk viscoelasticity is at the origin of this history effect. During a slip event, the friction tractions at the interface change almost instantaneously, which leads, between two ruptures, to a relaxation-resembling viscous effect that restores the stress concentration. We describe the decrease rate analytically and highlight that it is proportional to the ratio of the viscous over the instantaneous Young’s moduli, and illustrate it by varying the material properties in our simulations.

Electrically alterable switching characteristics have been observed in ferrite memory cores. Abnormal switching characteristics are caused by previous time‐limited switching and are not removed by subsequent ``hard'' saturation. The peaking time, peak amplitude, and magnitude of the flux change are all modified. It is proposed that the changes in switching behavior are due to formation of 360° Bloch walls during the combination of time‐limited switching and remagnetization to saturation.