Negative Hysteresis Research Articles

Study of the pitting corrosion of superduplex stainless steel and X-65 carbon steel during erosion–corrosion by cyclic polarisation technique

Erosion-enhanced corrosion behaviour of X-65 carbon steel and UNS S32750 superduplex stainless steel was investigated by electrochemical cyclic polarisation. The tests were performed using a jet slurry device coupled with a potentio-galvanostat at various jet velocities of 4, 6.5 and 9 m s−1 and impingement angles of 30 and 90˚ in a 3.5 wt-% NaCl water containing 6 wt-% silica sand particles. The results showed that increasing the jet velocity and impingement angle increased the corrosion rate of both alloys. Negative hysteresis and greater Erp than OCP were observed for superduplex stainless steel in all erosion–corrosion conditions that indicated the pitting resistance of the alloy. However, the low resistance of carbon steel against pitting during erosion–corrosion was demonstrated by positive hysteresis in the cyclic polarisation curves as well as SEM images of the eroded surfaces.

Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

Solution-processed graphene quantum dots (GQDs) possess a moderate bandgap, which make them a promising candidate for optoelectronics devices. However, negative photoconductivity (NPC) and hysteresis that happen in the photoelectric conversion process could be harmful to performance of the GQDs-based devices. So far, their origins and relations have remained elusive. Here, we investigate experimentally the origins of the NPC and hysteresis in GQDs. By comparing the hysteresis and photoconductance of GQDs under different relative humidity conditions, we are able to demonstrate that NPC and hysteresis coexist in GQDs and both are attributed to the carrier trapping effect of surface adsorbed moisture. We also demonstrate that GQDs could exhibit positive photoconductivity with three-order-of-magnitude reduction of hysteresis after a drying process and a subsequent encapsulation. Considering the pervasive moisture adsorption, our results may pave the way for a commercialization of semiconducting graphene-based and diverse solution-based optoelectronic devices.

Effects of salt concentration and spreading amounts on surface pressures of layers of latex particles grafted to polymer chains at interfaces between air and aqueous salt solutions

Polystyrene (PS) latex particles grafted to diacetone acrylamide chains were spread in layers at the air-aqueous interfaces of NaCl solutions. Their surface pressures were investigated as a function of the NaCl concentration in the water phase, at different initial surface concentrations of PS latex particles. At low initial surface concentrations of PS latex particles, the isotherms of the monolayers measured during compression-expansion cycles exhibited slightly a negative hysteresis, i.e. a decrease in surface pressure as the number of compression-expansion cycles increased, irrespective of the NaCl concentration. The isotherm obtained upon expansion was almost the same as the compression isotherm for three repeated compression-expansion cycles. On the other hand, at high initial concentrations of latex particles, in which the surface area per particle could reach much smaller values upon compression, the compression-expansion isotherms clearly showed a plateau region. In this region, PS latex particles were laterally close packed at the interface, irrespective of NaCl concentration as well as the number of cycles. The isotherm shape was strongly dependent on NaCl concentration; negative hysteresis was observed when NaCl concentrations were lower than 0.001 M and higher than 0.15 M, except for the plateau region in the expansion cycles. The isotherm recorded using a 0.025 M NaCl subphase exhibited negative hysteresis below the plateau region.

Observation of negative differential resistance in GaN-based multiple-quantum-well light-emitting diodes

Anomalous current–voltage behaviors, such as negative differential resistance (NDR) and current hysteresis, are observed in the room-temperature current–voltage (I-V) curves of InGaN/GaN multiple-quantum-well light-emitting diodes. It is found that the NDR can be observed in the positive voltage range of the I-V curve only when the samples are pretreated with a negative voltage before sweeping, and the NDR disappears permanently after an over-current treatment. The dependence of the NDR upon the negative voltage and sweeping conditions leads to the conclusion that a variation of the charging state of the defect-induced hole traps is responsible for the anomalous I-V behaviors. Therefore, NDR is excluded as a feature of the tunneling transport mechanism, especially in GaN-based devices with a high defect density.

Cyclic performance of concrete-encased composite columns with T- shaped steel sections

To study seismic performance of concrete-encased composite columns with T-shaped steel cross-section, twelve half-scale columns were tested under quasi-stastic cyclic loading. The result indicates that concrete-encased composite columns with Tshaped steel section possess good seismic performance. The failure modes include bending failure, shear-bond failure, shear compression failure and shear-composition failure. Unsymmetrical phenomenon of positive and negative hysteresis loop was shown evidently. Span ratio has a great influence on failure mode. The ductility performance decreases with increasing of axial compression level. As stirrup ratio increases, ductility and bearing capacity of columns are improved greatly, and energy dissipation capacity after yielding is enhanced. Cross tie can enhance ultimate bearing capacity, and lower strength attenuation and stiffness degradation on the later loading stage.

Effect of addition of HPBCD on diuron adsorption–desorption, transport and mineralization in soils with different properties

The influence of different soil properties on diuron adsorption and the effect of hydroxypropyl-β-cyclodextrin (HPBCD) on its desorption, leaching, and mineralization have been investigated. The significant variables on adsorption were organic matter (OM) content, aluminum oxides, and clay fraction. Diuron desorption from soils presents negative hysteresis when HPBCD solutions were used as an extractant, in comparison to the positive hysteresis when using Ca(NO3)2 solutions. Therefore, higher amounts of diuron were desorbed by HPBCD due to the formation of an inclusion complex that causes an increase in its solubility. However, the application of HPBCD in columns of selected soils did not cause increased leaching of the herbicide. Finally, the presence of HPBCD shows clearly an increase in the rate of mineralization of diuron in contaminated soils and a drastic reduction of DT50 values due to its increasing bioavailability. HPBCD is proposed as an efficient tool for diuron soil bioremediation.

Functional distance in human gait transition

The emerging understanding of the behavioral transitions that accompany the ascending and descending method of limits is in terms of “functional distance” — the degree to which a perceiver is disengaged from ordinary exploratory activities. Increasing functional distance results in negative hysteresis in contrast to the classical positive hysteresis more typical of ongoing activity. In the present study of human gait transitions on a treadmill, the functional distance between a perceiver and ordinary exploratory activities was manipulated in two ways: (1) “Active” participants, walking or running on a treadmill, were asked to anticipate the gait that would be required if treadmill speed were increased or decreased; and (2) “passive” participants, standing off a moving treadmill, were asked to report the gait they would use if they were on the treadmill at its current speed. As expected, the increase of functional distance from (1) to (2) reduced the amount of classical hysteresis and promoted negative hysteresis, that is, a lower transition speed for walk-to-run transitions (ascending trials) than for run-to-walk transitions (descending trials). These results complement empirical findings in other behavioral transition experiments. More broadly, they signify the role of perception-action cycles for grounding natural on-going perception. In particular, they support the assertion that perception and action are intertwined and that lack of information about an impending action has consequences for perceptual judgments.

On the Performance Degradation of Poly(3-Hexylthiophene) Field-Effect Transistors

Polymeric transistor degradation was investigated on bottom and top gate structures. Shelf-lifetime studies in both kinds of devices demonstrate an accelerated increase in effective charge carrier mobility, threshold voltage, and off current in modulus when poly(3-hexylthiophene) (P3HT) is exposed to atmospheric gases. Although P3HT is underneath PMMA dielectric and gold gate electrode films, electrical parameters degradation can be only delayed by 100 h. Therefore, only glass encapsulation of the active area is capable of effectively preventing current modulation decrease after exposure to atmospheric gases. Differently from their bottom-gate counterparts, capped top-gate TFTs clearly present negative threshold voltage and positive hysteresis. An interface with reduced deep traps concentration and electrical characterization influence on shallow traps filling are believed to play a significant role in these top-gate P3HT/PMMA transistors under operating conditions. Alternating gate voltage stress along 3000 cycles provides evidence of electrical sweep as a cause of performance degradation. Similarly, dc gate bias stress monitored for 127 min can impair current modulation and shifts threshold voltage depending on its sign. Finally, reversibility of both kinds of stress points that shallow traps are the major problem in these capped devices.

Interplay between order-parameter and system parameter dynamics: considerations on perceptual-cognitive-behavioral mode-mode transitions exhibiting positive and negative hysteresis and on response times.

A mathematical model is presented for the emergence of perceptual-cognitive-behavioral modes in psychophysical experiments in which participants are confronted with two alternatives. The model is based on the theory of self-organization and, in particular, the order parameter concept such that the emergence of a mode is conceptualized as an instability leading to the emergence of an appropriately defined order parameter. The order parameter model is merged with a second model that describes adaptation in terms of a system parameter dynamics. It is shown that the two-component model predicts hysteretic mode-mode transitions when control parameters are increased or decreased beyond critical values. The two-component model can account for both positive and negative hysteresis effects due to the interaction between order parameter and system parameter dynamics. Moreover, the model-based analysis reveals that response time curves look rather flat when response times are relatively decoupled from the mode-mode transition phenomenon. In general, response time curves exhibit a peaked close to the mode-mode transition point. In this context, the possibility is discussed that such peaked response time curves belong to the class of critical phenomena of self-organizing systems. In order to illustrate the relevance of peaked response time curves for future research and research reported in the past, results from a perceptual judgment experiment are reported, in which participants judged their ability to stand on a tilted slope for various angles of inclination. Response time curves were found that exhibited a peak around the mode-mode-transition points between "yes" and "no" responses.

Integral activity of intrapulmonary source of mechanical energy in healthy subjects and in patients with obstructive lung diseases

Two functional levels of mechanical energy intrapulmonary source have been viewed in this article for the first time. The first level is located into the perialveolar space. This level provides inspiratory and expiratory activity of the lungs together with respiratory muscles. Due to this, the inspiratory alveolar pressure is lower than the intrapleural pressure and the expiratory alveolar pressure is higher than the intrapleural pressure. This is deter mined by work of breathing measured as negative elastic hysteresis area and allows overcoming some nonelastic resistance of the lungs. The lung activity on overcoming the elastic resistance is estimated by multiplying the total work of breathing by a functional coefficient of lung elasticity (FCLE). The latter is calculated by dividing the total lung compliance by the dynamic lung compliance and reflects change in the elastic lung tension from spontaneous breathing level to the total lung compliance level. FCLE approximates 1 in healthy subjects and in patients with normal lung elastic recoil (LER). LER is lower and the total lung capacity is higher in lung obstructive diseases. Consequently, the total lung compliance could increase and FCLE could grow up to 10 in such cases (for instance, in severe emphysema). This leads to increasing lung activity on overcoming the elastic resistance up to 10 kgf × m / min or higher. Actually, this huge work of breathing is not performed due to the 2nd level of lung mechanical activity that is an active dilation of the large airways on expiration; this mechanism prevents valvular bronchial obstruction.

On Traffic Relaxation, Anticipation, and Hysteresis

Traffic oscillations, an unpleasant form of traffic congestion, have attracted the attention of researchers for years. When viewed in the so-called flow–density or speed–density phase plane, oscillatory traffic states often present themselves in the form of hysteresis loops. In this paper, the impacts of driver relaxation and anticipation on traffic flow are examined, and their link to traffic hysteresis is sought. Through an analysis of the trajectory data from NGSIM and a theoretical analysis of car-following models, it is revealed that traffic hysteresis is generated by an imbalance in driver relaxation and anticipation. Changing the strength of relaxation and anticipation can reproduce positive, negative, and double hysteresis loops, as well as aggressive and timid driving behavior. It is further shown that the relative positions of acceleration and deceleration phases with respect to the equilibrium state are not unique and are determined by the comparative strength of relaxation and anticipation in different traffic conditions. This study suggests that traffic hysteresis can be suppressed by balancing driver relaxation and anticipation, and stop-and-go traffic can be smoothed by eliminating aggressive driving in congested traffic.

OPTIONS FOR REGISTRATION OF THE LUNGS MAXIMUM MECHANICAL ACTIVITY, WHICH IS AIMED AT OVERCOMING INTERNAL-LUNG RESISTANCE

The paper presents the results of assessing general and elastic lung hysteresis in 21 healthy volunteers and 28 patients with community-acquired pneumonia. Negative elastic hysteresis was detected in 14 healthy volunteers and 18 patients with community-acquired pneumonia. For the first time ever, it was demonstrated that, under the conditions of an interrupted air flow, 4 healthy volunteers and 2 patients with community-acquired pneumonia were characterized with the inversion of not only elastic but also general lung hysteresis. In case of pneumonia, despite the increase in tissue friction resulting from the generalized escalation of the alveolar-capillary permeability, the inversion of both elastic and general lung hysteresis takes place as often as in healthy people. It can be explained with the intensification of the mechanical activity of the lungs as a compensatory reaction in the mechanical system of the external respiration organs in case of pneumonia.

Theory of charge transport in molecular junctions: from Coulomb blockade to coherent tunneling.

We study charge transport through molecular junctions in the presence of electron-electron interaction using the nonequilibrium Green's function techniques and the renormalized perturbation theory. In the perturbation treatment, the zeroth-order Hamiltonian of the molecular junction is composed of independent single-impurity Anderson's models, which act as the channels where charges come through or occupy, and the interactions between different channels are treated as the perturbation. Using this scheme, the effects of molecule-lead, electron-electron, and hopping interactions are included nonperturbatively, and the charge transport processes can thus be studied in the intermediate parameter range from the Coulomb blockade to the coherent tunneling regimes. The concept of quasi-particles is introduced to describe the kinetic process of charge transport, and then the electric current can be studied and calculated. As a test study, the Hubbard model is used as the molecular Hamiltonian to simulate dimeric and trimeric molecular junctions. Various nonlinear current-voltage characteristics, including Coulomb blockade, negative differential resistance, rectification, and current hysteresis, are shown in the calculations, and the mechanisms are elucidated.

Transpassivity characterization of the alloy UNS N08367 in a chloride-containing solution

We investigate the transpassivity of super-austenitic stainless steel UNS N08367 in 2.5 M LiCl solution by using cyclic potentiodynamic polarization (CPP), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). The CPP curve exhibits negative hysteresis, which indicates a transpassive dissolution process instead of pitting corrosion. The transition from the passive region to the transpassive region is characterized by EIS and equivalent circuit analysis. During the transpassive dissolution of the N08367 alloy, two reactions of adsorbed intermediates are dominant, as indicated by the two inductive loops at the transpassive region. The first inductive loop is associated with the faster reaction, i.e., the adsorption of Fe intermediates. This fast reaction is significantly influenced by the preferential dissolution of Fe during the transpassive dissolution. The second inductive loop is correlated with the adsorption of the Cr intermediate. In contrast to Fe, the Cr content on the surface increases in the transpassive region compared with the content in the passive region. The XPS spectra support the time and frequency domain approach for the preferential dissolution, and the dominant species resulted from the interfacial processes at the transpassive region.

Effect of temperature on surface pressure–area isotherms and surface dilational moduli of poly(N-isopropyl acrylamide) monolayers spread at air–water interface

The surface pressure–area isotherms and surface dilational moduli of poly(N-isopropyl acrylamide) (PNIPAM) monolayers spread at an air–water interface were measured as a function of temperature from 5°C to 35°C. The isotherms of the PNIPAM monolayers measured by compression–expansion cycles clearly showed a negative hysteresis, i.e., a decrease in the surface pressure as the number of cycles increased, irrespective of temperature. An increase in temperature caused a decrease in surface pressure in the semidilute region and increase in the surface pressure in the collapse state below the lower critical solution temperature (LCST) of PNIPAM in water, ca. 32°C. The surface moduli in the semidilute region determined from the first loop of Lissajous orbits at fixed surface pressure and strain, slightly decreased with increasing temperature, indicating that the elastic forces for the entanglement of PNIPAM chains in the monolayers decreased with a decrease in the solvent power conditions of PNIPAM in water.

A review of the studies using buprenorphine in cats.

Pain management is a crucial component of feline medicine and surgery. This review critically evaluates studies using buprenorphine in cats and highlights the clinical application of the opioid in this species. The pharmacokinetic‐pharmacodynamic (PK‐PD) modeling of IV buprenorphine has been best described by a combined effect compartmental/receptor association‐dissociation model with negative hysteresis. Therefore, plasma concentrations of the drug are not correlated with analgesia, and clinicians should not expect to observe pain relief immediately after drug administration. In addition, a ceiling effect has not been demonstrated after administration of clinical doses of buprenorphine in cats; dosages of up to 0.04 mg/kg have been reported. The route of administration influences the onset, duration, and magnitude of antinociception and analgesia when using this drug in cats. At clinical dosages, the SC route of administration does not appear to provide adequate antinociception and analgesia whereas the buccal route has produced inconsistent results. Intravenous or IM administration at a dosage of 0.02–0.04 mg/kg is the preferred for treatment of pain in the acute setting. A literature search found 14 clinical trials evaluating buprenorphine sedation, analgesia, or both in cats. There were 22 original research studies reporting the antinociceptive effects of buprenorphine by means of thermal threshold, mechanical threshold, or both, minimal alveolar concentration, or PK‐PD. Individual variability in response to buprenorphine administration has been reported, indicating that buprenorphine may not provide sufficient analgesia in some cats. Pain assessment is important when evaluating the efficacy of buprenorphine and determining whether additional analgesic treatment is needed.

The Observations of the IR Sensitivity Enhancement, Negative Differential Resistance and Hysteresis in a Microelectronic Gas Discharge Device with GaP

In this paper, some interesting features of a microelectronic gas discharge device with GaP semiconductor are reported. The device is a complicated plasma system with a metal anode and a GaP cathode. A discharge occurs in the micro-scaled gap, when a voltage larger than the breakdown value is applied between these electrodes. Since large region of applied voltages are scanned in the microelectronic gas discharge device, both Townsend and glow regimes are clearly observed and a complete electrical and optical responses of the device has been clarified. Following the increase of U gradually, different light emission intensities occur as a result of discharge current I. An IR light source is also used in order to test the IR excitation of the microstructure. Although it has been believed that the GaP is sensitive to UV and visible regions, it has been proven for the first time that the IR sensitivity of GaP can be enhanced by using microelectronic gas discharge device, when an appropriate parameter set is applied. Moreover, a negative differential resistance regime, which is important for the high frequency microwave applications, has been observed at moderate voltages. In addition to the negative differential resistance regime, certain hysteresis behaviour is also observed in the sweep up/down cases of U. DOI: http://dx.doi.org/10.5755/j01.eee.20.1.6173

Incipient plasticity in 4H-SiC during quasistatic nanoindentation

Silicon carbide (SiC) is an important orthopedic material due to its inert nature and superior mechanical and tribological properties. Some of the potential applications of silicon carbide include coating for stents to enhance hemocompatibility, coating for prosthetic-bearing surfaces and uncemented joint prosthetics. This study is the first to explore nanomechanical response of single crystal 4H-SiC through quasistatic nanoindentation. Displacement controlled quasistatic nanoindentation experiments were performed on a single crystal 4H-SiC specimen using a blunt Berkovich indenter (300nm tip radius) at extremely fine indentation depths of 5nm, 10nm, 12nm, 25nm, 30nm and 50nm. Load–displacement curve obtained from the indentation experiments showed yielding or incipient plasticity in 4H-SiC typically at a shear stress of about 21GPa (~an indentation depth of 33.8nm) through a pop-in event. An interesting observation was that the residual depth of indent showed three distinct patterns: (i) positive depth hysteresis above 33nm, (ii) no depth hysteresis at 12nm, and (iii) negative depth hysteresis below 12nm. This contrasting depth hysteresis phenomenon is hypothesized to originate due to the existence of compressive residual stresses (upto 143MPa) induced in the specimen by the polishing process prior to the nanoindentation.

How do supporters perceive positive and negative psychological momentum changes during a simulated cycling competition?

ObjectiveThe present study examined changes in sport supporters' psychological momentum (PM) during a simulated cycling competition through the lens of the dynamical systems approach. DesignParticipants were asked to support one of two competing cyclists involved in a race that was displayed on a screen in a lecture hall. MethodThe race scenario was manipulated so that the image of the supported cyclist underwent either positive or negative momentum. At regular intervals, participants indicated their PM perceptions during the race. ResultsPM perceptions rapidly changed at the onset of both the positive and negative momentum sequences and then remained stable, reflecting negative hysteresis. Supporters tended to anticipate the future performance of a given athlete on the basis of their current performance. Moreover, this anticipatory tendency was stronger during the positive momentum sequence than during the negative momentum sequence. ConclusionThese results provide initial insights into how PM perceptions of sport supporters change during a competition.

Vagueness and Order Effects in Color Categorization

This paper proposes an experimental investigation of the use of vague predicates in dynamic sorites. We present the results of two studies in which subjects had to categorize colored squares at the borderline between two color categories (Green vs. Blue, Yellow vs. Orange). Our main aim was to probe for hysteresis in the ordered transitions between the respective colors, namely for the longer persistence of the initial category. Our main finding is a reverse phenomenon of enhanced contrast (i.e. negative hysteresis), present in two different tasks, a comparative task involving two color names, and a yes/no task involving a single color name, but not found in a corresponding color matching task. We propose an optimality-theoretic explanation of this effect in terms of the strict-tolerant framework of Cobreros et al. (J Philos Log 1---39, 2012), in which borderline cases are characterized in a dual manner in terms of overlap between tolerant extensions, and underlap between strict extensions.