Auditory Efferent System Influences the Auditory Overshoot Phenomenon- An Auditory Brainstem Response Study in Guinea Pigs

Introduction: Detection of a brief tonal signal at the beginning of a longer masking noise is difficult, but it becomes easier when the onset of signal is delayed. This phenomenon is known as overshoot or temporal effect. Aiming of our study was to investigate the effect of the auditory efferent nerves (AENs) function on the auditory electrophysiological overshoot, further introducing an objective tool examining one of the AENs performances. Therefore, the effect and the trend of changes induced by low and high-frequency stimuli on electrophysiological overshoot in different delay onset time (DOTs) between the signal and the noise before and after dissecting the AENs were studied. Methods: Right internal auditory canals were exposed in 16 young male guinea pigs weighing 250 to 350 g. The inferior and posterior vestibular nerves that are known to carry AENs were transected in half of the subjects. Then, the ABR waveforms were recorded at 16 & 8 kHz tone burst stimuli at 0, 30, 60, 100 ms DOTs relative to wide-band noise. The value of latency of ABR waves I and III were compared among the different DOTs and five signal-to-noise ratios (SNRs) before and after the surgery. Results: By increasing DOTs, the latency of ABR waves I& III decreased in the control group before and after the surgery and the case group before surgery at 16 kHz. However, the observed overshoot-like effect disappeared after the surgery in the case group. The wave's latency I& III increased from 0 to 30 ms, remained approximately constant from 30 to 60ms, and then began to decrease toward 100 ms DOTs. However, none of the measurements at 8 kHz, before and after surgery at both groups showed an overshoot effect. Conclusion(s): By using the ABR paradigm, the overshoot phenomenon disappeared after the transection of AENs. The results confirmed the role of the efferent system on auditory overshoot. Therefore, an objective tool to measure auditory efferent function is provided.

Exact Solution of the Start-Up Electroosmotic Flow of Generalized Maxwell Fluids in Triangular Microducts

Unsteady electroosmotic flow of generalized Maxwell fluids in triangular microducts is investigated. The governing equation is formulated with Caputo-Fabrizio time-fractional derivatives whose orders are distributed in the interval [0, 1). The linear momentum and the Poisson-Boltzmann equations are solved analytically in tandem in the triangular region with the help of the Helmholtz eigenvalue problem and Laplace transforms. The analytical solution developed is exact. The solution technique we use is new, leads to exact solutions, is completely different from those available in the literature and is applicable to other similar problems. The new expression for the velocity field displays experimentally observed 'velocity overshoot' as opposed to existing analytical studies none of which can predict the overshoot phenomenon. We show that when Caputo-Fabrizio time-fractional derivatives approach unity the exact solution for the classical upper convected Maxwell fluid is obtained. The presence of elasticity in the constitutive structure alters the Newtonian velocity profiles drastically. The influence of pertinent parameters on the flow field is explored.

Analysis of the Influence of Renewable Generator Frequency Endurance Capability on Low-Frequency Load Shedding: A Hunan Case Study

With the rapid development of renewable generators such as distributed photovoltaic and profound changes of the power structure, this paper analyzes the frequency characteristics of the power system with high penetration of renewable generations in the process of low-frequency load shedding and discusses the influence of the distributed renewable generator frequency endurance capabilities on the implementation effect of low-frequency load shedding in detail. Finally, the influences of the distributed renewable generator frequency endurance capability and the capacities of the distributed renewable generator on frequency response characteristics of an actual Hunan power grid are simulated. The simulation results show that more distributed photovoltaic capacity without frequency endurance capability leads to deeper frequency drops after the disturbance and requires more basic rounds of load shedding. When the penetration rate of distributed photovoltaic is too high, it may cause load shedding, resulting in power grid load losses and, at the same time, leading to an overshoot phenomenon in the process of frequency recovery. Therefore, the influence of distributed photovoltaic on the control of low-frequency load shedding should be considered when designing low-frequency load shedding schemes for the power grid with high penetration of distributed photovoltaic.

Predictive Set Point Modulation Charging of Autonomous Rail Transit Vehicles

Autonomous rail transit (ART) vehicle is a new type of urban rail transportation, which has good development prospects. It is powered by onboard supercapacitors, which are charged at midway stations. It requires short charging time and fast charging speed. Usually, multiple chargers are used in parallel for charging. However, this will cause an overshoot phenomenon during charging, and the overshoot of multiple chargers will be superimposed on the supercapacitor, affecting the stability and life of both supercapacitors and chargers. In this paper, we propose a predictive set point modulation charging method, which can reduce the system’s overshoot and increase the reliability of the system. First, the state-space averaging method is used to establish the electronic physical model of the multicharger system. Secondly, a predictive set point modulation charging control method is designed, and the closed-loop model of the proposed charging system is developed using the buck diagram. The effectiveness of the proposed method is verified through extensive simulation and experiments. The experimental results show that compared with the classical design method, the proposed method can effectively suppress the current overshoot.

Development of hybrid fire testing by real-time subdivision of physical and numerical substructures

Purpose This study aims to evaluate the feasibility of a hybrid fire testing by real-time subdivision of physical and numerical substructures (NSs) on simplified structures as a milestone in the development of the method. Design/methodology/approach An interface where the data was exchanged between a finite element software and a hydraulic jack regulator using text files has been developed and applied to perform two experimental campaigns of nine tests on simple steel frame structures with different thermal loading conditions. In the first experimental campaign, the physical substructure (PS) was assumedly protected by insulating material, while the NS was uniformly exposed to ISO 834 fire on all sides. The difference of the second experimental campaign from the first one was that the PS was heated on one side. Findings The experimental results showed how a gap between the determined equilibrium position and the “real” position caused by the time lag, as well as an overshoot phenomenon due to the non-synchronized action of both substructures, may occur. From the identification of the overshoot, two paths of development spring to mind to reduce the delay of the NS. Originality/value In the context that the number of proposal theoretical algorithms continues to increase with the absence of real experimental adjustments, such experimental results and the associated analysis constitute additional understandings to identify possible paths of improvements that might have been missed or could not be accessed through previous studies.

USE OF SENTINEL-2 SATELLITE DATA TO ASSESS RUNNING EVENTS IN THE DON DELTA

Drifting phenomena pose a significant threat to human life and the economy. The estuary of the Don is an ideal testing ground for surge phenomena. The largest surges can reach 2.8 m at the sea edge of the Don delta, the largest surges – 3.3 m. In addition, this area is highly urbanized and has great economic importance. The work is devoted to the use of Sentinel 2 satellite imagery data to assess the areas of drainage of the bottom of the Taganrog Bay and the sea part of the Don delta as a result of wind-driven phenomena. The paper considers the period from 2015 to 2020. The study of surges and overshoots in the mouth area of the Don River is based on observational data of the standard hydrometeorological network of Roshydromet. A combination of spectral channels has been determined, which allows to clearly distinguish the water-land boundary. The main research methods are the method of classification with training, which allows you to identify the most characteristic classes of objects. To assess the quality of the classification carried out, the classification accuracy was assessed using the inconsistency matrix, which confirmed the validity of the method. As a result of the classification carried out, the areas of bottom drying were calculated. The dependence of the bottom drainage value on the speed and duration of northeast and east winds is shown. Analysis of the data showed that a combination of satellite information, meteorological data and data from level gauges is required to monitor the overshoot phenomenon. This publication was prepared as part of the GZ SSC RAS, № g. project 01201363188

Investigation on the Overshoot of Transient Open-Circuit Voltage in Methylammonium Lead Iodide Perovskite Solar Cells

Although the performance of hybrid organic-inorganic perovskite solar cells (PSCs) is encouraging, the detailed working principles and mechanisms of PSCs remain to be further studied. In this work, an overshoot phenomenon of open-circuit voltage (Voc) was observed when the illumination light pulse was switched off. The evolution of the Voc overshoot was systematically investigated along with the intensity and the width of the light pulse, the background illumination, and pretreatment by different bias. Based on the experimental results, we could conclude that the Voc overshoot originated from carrier motion against carrier collection direction, which happened at the ionic-accumulation-induced band bending areas near the interfaces between the perovskite active layer and the two carrier transport layers. The investigation on the Voc overshoot can help us to better understand ionic migration, carrier accumulation, and recombination of PSCs under open-circuit conditions.

Second-order modeling for the pulmonary oxygen uptake on-kinetics: a comprehensive solution for overshooting and nonovershooting responses to exercise

The human oxygen uptake (V̇o2) response to step-like increases in work rate is currently modeled by a First Order System Multi-Exponential (FOME) arrangement. Because of their first-order nature, none of FOME model’s exponentials is able to model an overshoot in the oxygen uptake kinetics (OV̇o2K). Nevertheless, OV̇o2K phenomena are observed in the fundamental component of trained individuals’ step responses. We hypothesized that a Mixed Multi-Exponential (MiME) model, where the fundamental component is modeled with a second- instead of a first-order system, would present a better overall performance than that of the traditional FOME model in fitting V̇o2 on-kinetics at all work rates, either presenting or not OV̇o2K. Fourteen well-trained male cyclists performed three step on-transitions at each of three work rates below their individual lactate thresholds’ work rate (WRLT), and two step on-transitions at each of two exercise intensities above WRLT. Averaged responses for each work rate were fitted with MiME and FOME models. Root mean standard errors were used for comparisons between fitting performances. Additionally, a methodology for detecting and quantifying OV̇o2K phenomena is proposed. Second order solutions performed better ( P < 0.000) than the first-order exponential when the OV̇o2K was present, and did not differ statistically ( P = 0.973) in its absence. OV̇o2K occurrences were observed below and, for the first time, above WRLT (88 and 7%, respectively). We concluded that the MiME model is more adequate and comprehensive than the FOME model in explaining V̇o2 step on-transient responses, considering cases with or without OV̇o2K altogether. NEW & NOTEWORTHY To our knowledge, this is the first study applying second-order system equations to model V̇o2 on-kinetics, which is useful for both mathematical representation and physiological understanding of the overshoot phenomenon manifesting in the fundamental components of some step responses. Moreover, an objective methodology for detecting and quantifying this overshoot that considers data from the whole response is proposed. Finally, this is the first work detecting overshoot occurrences outside the moderate domain of exercise.