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This study investigated the dynamic characteristics of thermocouples by using double-pulse laser excitation for dynamic temperature calibration under extreme conditions. An experimental device was constructed for double-pulse laser calibration; the device uses a digital pulse delay trigger to precisely control the double-pulse laser to achieve sub-microsecond dual temperature excitation with adjustable time intervals. The time constants of thermocouples under single-pulse laser excitation and double-pulse laser excitation were evaluated. In addition, the variation trends of thermocouple time constants under different double-pulse laser time intervals were analyzed. The experimental results indicated that the time constant increases and then decreases with the decrease in the time interval of the double-pulse laser. A method for dynamic temperature calibration was established for the evaluation of the dynamic characteristics of temperature sensors.

The divertor is usually exposed to extreme incident heat flux conditions in nuclear fusion engineering and its ability to remove the heat is extremely crucial for the safe operation of magnetic confinement nuclear fusion device. The evaluation of the heat removal capacity of the divertor has been always based on high heat flux (HHF) tests. Yet such methods are only available for the small size of experimental components, it is more difficult to compare under different loading and cooling conditions. In order to assess the heat removal capacity in real time and accurately, a new method was developed to characterize the heat removal capacity of the divertor and other high heat load components based on the cooling water thermal decay time constant, the time constants model has also been established. The thermal decay time constant was obtained by fitting the characteristic curves of the water temperature differences with time during the cooling phase of different components under HHF tests. This index is used to quantitatively analyze, characterize and evaluate the heat transfer capacity of the system of the divertor.

The methods for the experimental determination of the time constant of measuring transducers are described. The method is based on determining the parameters of the steady-state response of the measuring transducer using a periodic sequence of rectangular pulses of known time pulse and repetition period as an input signal. Expressions for determining the time constant for various response parameters: maximum, minimum, average, and average rectified values are given. The evaluation of the measurement uncertainty for each of the obtained expressions is made.The proposed method has high accuracy and low labour intensity in comparison with the known graph-analytical methods.

Stringent animal welfare principles are forcing undergraduate instructors to avoid the use of animals. Therefore, many hands-on lab sessions using laboratory animals are progressively replaced by computer simulations. These versatile software simulations permit the observation of the behavior of biological systems under a great variety of experimental conditions. While this versatility is important, computer simulations often work even when a student makes wrong assumptions, a situation that poses its own pedagogical problem. Hands-on learning provides pupils with the opportunity to safely make mistakes and learn organically through trial and error and should therefore still be promoted. We propose an electronic model of an excitable cell composed of different modules representing different parts of a neuron - dendrites, soma, axon and node of Ranvier. We describe a series of experiments that allow students to better understand differences between passive and active cell responses and differences between myelinated and demyelinated axons. These circuits can also be used to demonstrate temporal and spatial summation of signals coming to the neuron via dendrites, as well as the neuron coding by firing frequency. Finally, they permit experimental determination along with theoretical calculations of important biophysical properties of excitable cells, such as rheobase, chronaxie and space constant. This open-source model has been successfully integrated into an undergraduate course of the physiology of excitable cells and student feedback assessment reveals that it helped students to understand important notions of the course. Thus, this neuromorphic circuit could be a valuable tool for biophysics and neuroscience courses in other universities., (Copyright © 2024 Faculty for Undergraduate Neuroscience.)

A uni-molecular layer of lipids at air-water interface mimicking one of the leaflets of the cellular membrane provides a simple model to understand the interaction of any foreign molecules with the membrane. Here, the interactions of protein Kalata B1 (KB1) of cyclotide family with the phospholipids 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG), and 1,2-distearoyl-sn-glycero-3-ethylphosphocholine chloride salt (DSEPC) have been investigated. The addition of KB1 induces a change in pressure of the lipid monolayers. The characteristic time of the change in pressure is found to be dependent on the electrostatic nature of the lipid. Even though the protein is weakly surface active, it is capable of modifying the phase behavior and elastic properties of lipid monolayers with differences in their strength and nature making the layers more floppy. The KB1-lipid interaction has been quantified by calculating the excess Gibb's free energy of interaction and the 1-anilino-8-naphthalenesulfonate (ANS) binding studies. The interaction with zwitterionic DPPC and negatively charged DPPG lipids are found to be thermodynamically favorable whereas the protein shows a weaker response to positively charged DSEPC lipid. Therefore, the long ranged electrostatic is the initial driving force for the KB1 to recognize and subsequently attach to a cellular membrane. Thereafter, the hydrophobic region of the protein may penetrate into the hydrophobic core of the membrane via specific amino acid residues. • Cyclotides interaction with the lipid membranes play major role in their biological activities. • KB1 can modify the phase behavior and elastic properties of lipid monolayers. • KB1 shows thermodynamically favorable interaction with neutral and anionic lipids. • Long range electrostatic is the initial driving force for KB1 attachment to a cellular membrane. [ABSTRACT FROM AUTHOR]

Purpose. To conduct an experimental study on M102 aluminum alloy bulk content characterization under cyclic loadings for precision applications such as balance machines, optical, and laser instruments. M102 (AL-C-O) dispersion-reinforced aluminum alloy was chosen because of its ability to withstand temperatures beyond 200 °C and has a better strength than precipitationhardened Al alloys at room temperature. A CNC milling machine is used to manufacture test samples with longitudinal machining directions. A constant time interval is set for the fabric – a quarter-hour span, which is based on the investigation of inelastic and plastic deformations in the nanoscale. Methodology. An electromagnetic test instrument applies a tensile stress range of 10 to 145 N/mm² to samples with particular shape. It should be noted that interferometers and capacitive sensors were used to measure all forms of deformations with and without loading. The experiments are carried out in a temperature-stable environment of 30.5 °C; measurements are taken within a residual strain range of 10 microns. Findings. The results obtained show that results for inelastic deformations for samples of longitudinal cuts direction at 30.5 °C were measured under 150 N/mm² stress as 500 nm inelastic deformation and 100 nm plastic deformation were measured, which is much higher than aluminum alloy studied before at room temperature (20 °C). Furthermore, it was found that the time constant of the M102 (AL–C–O) aluminum alloy samples was double times higher than that for other samples, Originality. For the first time, a study has been conducted on inelastic and plastic deformations in the nanoscale for characterization of M102 aluminum alloy bulk content under cyclic loadings for precision applications. Practical value. One of the main factors affecting the using of other materials than steel in precision applications such as balance machines, optical, and laser instruments is measurement and determination of inelastic, plastic and time constant of the process of delamination of materials of different aluminum alloys since they are nonmagnetic, are easily machined and shaped. This will bring new products and opportunities for these materials. [ABSTRACT FROM AUTHOR]

We studied the transient local surface temperature response that occurs when jet impinging of nitrogen gas is applied to the surface to which a pulsating heat flux is applied. After manufacturing a micro jet impinging device, which was composed of three parts—a silicon wafer, a vinyl sticker, and a Pyrex wafer—nitrogen gas was used as working fluid and the velocity was 344.8 m/s, corresponding jet Reynolds was 1467. And the amplitudes of heat fluxes varied from 5.67 to 16.17 W/cm2, the frequency also varied from 0.1 to 1000 Hz, then temperature response of RTDs was acquired. For example, when a heat flux, 8.5 W/cm2, was applied with a frequency of 0.1 Hz, the highest and lowest temperatures of RTD located on the center of the heater and under indirect jets were 30.2 °C and 20.7 °C. From the acquired results, the time constant of the device was estimated between 17 ms and 32 ms, and this result shows the conjugated mode of conduction and convection of heat transfer. To understand the dominant heat transfer, we decoupled the conduction mode and the convective heat transfer mode through analytical calculations and confirmed that the time constants were 11 µs and 128 ms, respectively. In addition, the heat transfer coefficient was inversely calculated through numerical calculation by simulating the RTD manufactured in the device, and through this, it was confirmed that the dimensionless time constant was related to the Nu number and the correlation was developed as τ/t = 3.51Nu−1.067 for f ≤ 1 Hz. [ABSTRACT FROM AUTHOR]

Transient regime effects are particularly important in fuel cells designed for vehicles. Three‐dimensional modeling of a proton exchange membrane fuel cell with a serpentine channel is presented, and the response of the fuel cell to a step‐change in the mass flow rates is analyzed by using the computational fluid dynamics techniques. After a validation study of the mathematical and numerical model, step increases of 20% in mass flow rates are applied to the inlet boundary conditions, and time dependent power and current density responses of the fuel cell are analyzed. Polarization curves are generated for the assessment of the fuel cell performance, and their variations in time are presented. The results show that current and power densities increase with time at low cell voltage values due to concentration losses; however, increases in power and current are negligible at high voltages. [ABSTRACT FROM AUTHOR]

We studied the transient local surface temperature response that occurs when jet impinging of nitrogen gas is applied to the surface to which a pulsating heat flux is applied. After manufacturing a micro jet impinging device, which was composed of three parts—a silicon wafer, a vinyl sticker, and a Pyrex wafer—nitrogen gas was used as working fluid and the velocity was 344.8 m/s, corresponding jet Reynolds was 1467. And the amplitudes of heat fluxes varied from 5.67 to 16.17 W/cm2, the frequency also varied from 0.1 to 1000 Hz, then temperature response of RTDs was acquired. For example, when a heat flux, 8.5 W/cm2, was applied with a frequency of 0.1 Hz, the highest and lowest temperatures of RTD located on the center of the heater and under indirect jets were 30.2 °C and 20.7 °C. From the acquired results, the time constant of the device was estimated between 17 ms and 32 ms, and this result shows the conjugated mode of conduction and convection of heat transfer. To understand the dominant heat transfer, we decoupled the conduction mode and the convective heat transfer mode through analytical calculations and confirmed that the time constants were 11 µs and 128 ms, respectively. In addition, the heat transfer coefficient was inversely calculated through numerical calculation by simulating the RTD manufactured in the device, and through this, it was confirmed that the dimensionless time constant was related to the Nu number and the correlation was developed as τ/t = 3.51Nu−1.067 for f ≤ 1 Hz. [ABSTRACT FROM AUTHOR]

We consider an i.i.d. supercritical bond percolation on ℤd, every edge is open with a probability p > pc(d), where pc(d) denotes the critical parameter for this percolation. We know that there exists almost surely a unique infinite open cluster 풞p. We are interested in the regularity properties of the chemical distance for supercritical Bernoulli percolation. The chemical distance between two points x, y ∈ 풞p corresponds to the length of the shortest path in 풞p joining the two points. The chemical distance between 0 and nx grows asymptotically like nμp(x). We aim to study the regularity properties of the map p → μp in the supercritical regime. This may be seen as a special case of first passage percolation where the distribution of the passage time is Gp = pδ1 + (1 − p)δ∞, p > pc(d). It is already known that the map p → μp is continuous. [ABSTRACT FROM AUTHOR]

In this work, a novel 3-D equivalent circuit model of thermoelectric microelectro-mechanical system (MEMS) microwave power sensor is proposed. According to the model, the 3-D temperature distribution and the response time of the thermoelectric MEMS microwave power sensor are obtained. The thermoelectric MEMS microwave power sensor is designed and fabricated based on GaAs monolithic microwave integrated circuit (MMIC) technology. The measured results show that the sensitivity of the sensor is 0.06 mV/mW at 10 GHz and the time constant is 85 μs. The theoretical results of the model show that the sensitivity is 0.076 mV/mW at 10 GHz and the time constant is 56.24 μs. The measured results are relatively consistent with the theoretical results. Furthermore, the heat dissipation in the substrate can be obtained accurately, and the transient response of the sensor can be further studied according to the 3-D equivalent circuit model. Therefore, this work has a certain reference value and guiding significance for the research of thermoelectric MEMS microwave power sensors. [ABSTRACT FROM AUTHOR]

An analytical model of the void closure during diffusion bonding was established by coupling finite element analysis (FEA) based on the deformation mechanism and numerical analysis based on the diffusion mechanism. The maximum stress was concentrated at the tip of the microconvex in contact with the bonding interface. With increasing bonding temperature and pressure, the stress concentration region moved from the tip of the microconvex region to the void neck region. The stress distribution was concentrated on the tip of the microconvex region (void neck region) to the opposite direction of the applied bonding pressure. Using the model, the characteristic time parameter (time constant) t c was defined based on the evolution of the void closure. At this moment, the predicted bonded ratio was the sum of (1 −1/e) times the normal limit bonded ratio and 1/e times the normal initial bonded ratio. Furthermore, a model for predicting the bonding time was established by coupling the required bonded ratio and the limitation of the deformation rate, the model can be used to predict the bonding time within the operation window. Contour maps of time constant (t c /min) and the nominal limit bonded ratio (f ult /%) were constructed for visual representation. [ABSTRACT FROM AUTHOR]

Time cannot be directly perceived; instead, its flow is inferred from the influx of sensory information. To prevent sensory overload, attentional mechanisms split up information into processable units. This portioning remains imperceptible to the individual. However, the length of these units still influences the speed of perception and the speed at which behaviors are performed. Previous studies have focused on establishing the length of these units in various mammalian species – mainly humans – by measuring different types of behaviors, including gaze. However, no such studies have been conducted on birds. We measured duration of ravens’ (Corvus corax) single gazes towards selectable objects before a choice was made, and compared it with that of humans in a similar set up. The raven gaze durations were approximately half those of humans (which fell slightly short of previously established ranges). We hypothesize that these differences are mainly due to the much higher so-called flicker-fusion-frequency in birds, which makes their vision faster in the sense that it picks up more information per time unit than mammalian vision does. We further discuss that the speed of perception might influence the general speed of cognitive processing in more complex tasks as well, and suggest that the addition of a temporal component in comparative cognitive studies might be informative.

Mechanical ventilation is an important strategy to manage patients with respiratory ailments in the acute as well as chronic setups. To be able to do so, we need a good understanding of the physiology of the respiratory system and the disease pattern. Two major components of the lung physiology are compliance and resistance and these define time constants (TCs). Compliance is the measure of distensibility of lungs. It is the change in pressure by the change in volume. Resistance is the opposing force that is created when air flows in the airway. Compliance and resistance together produce an entity called TC. TC defines the amount of time taken in seconds for the lung unit to fill or empty. TCs normally vary within the lungs and do more so in the diseased lungs. This article gives an overview of TCs and its components for the better understanding of the reader.

Measurement error occurs if the requirements of undistorted measurements cannot be satisfied by dynamic component characteristics of the sensor. Amplified time constant and longer thermal response time of armored thermocouple is caused by its additional protective cover structure and the inherent thermal inertia of the internal temperature measuring element. Therefore, there is hysteresis dynamic characteristic in actual measurement of sensor. This paper proposes an accurate compensation of armored thermocouple based on fireworks algorithm that balances the contradiction between the accuracy of the existing solution and the complexity of the solution, corrects the measured thermocouple temperature signal. Weight factor is innovatively introduced to design the fitness function of fireworks algorithm, and the iterative process is sectionally executed that achieves the improvement of time constant and thermal response time of armored thermocouple. Finally, results are given in the simulation section. Dynamic compensation time is reduced from 537ms to 130ms, which is 75.79% lower than before compensation result. Moreover, the thermal response time is reduced from 345ms to 110ms, which is 68.16% lower than the before compensation result. From the experimental results, we can observe that the proposed method in this paper can broaden the working bandwidth of the thermocouple sensor through establishing dynamic mathematical model of thermocouple. After compensation, the dynamic characteristics of armored thermocouple are close to bare bead thermocouple without protective sleeve. The proposed method can replace easily damaged bare bead thermocouple to realize accurate measurement in harsh temperature measurement environments without need frequent replacement, which also improves economic benefits. [ABSTRACT FROM AUTHOR]

In this study we investigate the time and space transition characteristics of DC electric field in SF 6 gas from the initial state DC-on to final DC steady-state in gas-solid composite insulation systems. Using a simple rod-electrode configuration and actual insulating epoxy-spacer model, the electric field distributions of the epoxy-spacer in SF 6 gas and time constant T of electric field formation from DC-on to DC steady-state are calculated based on the electric conduction characteristics. In addition, the emerging electric field distributions due to accumulated charge on solid insulator surface are introduced to elucidate the time transition process of electric field stress in the gap between HV conductor and GND. As a result, we quantitatively clarify that the time constant T of electric field formation are highly dependent on the non-uniform factor η and location of the gap space in the electrode configuration under non-uniform DC electric field. The locations with higher electric field stress in the gap space have the shorter time constant T. In addition, the time transition process of electric field stress in SF 6 gas depends on the gap space and the location of maximum electric field change during time transition. Especially, we clarify that the highest electric field stress in SF 6 gas may emerge in actual GIS structure based on the time transition process of emerging electric field due to accumulated charge. [ABSTRACT FROM AUTHOR]

Background: Cerebral vasospasm (VS) and delayed cerebral ischemia (DCI) constitute major complications following subarachnoid hemorrhage (SAH). A few studies have examined the relationship between different indices of cerebrovascular dynamics with the occurrence of VS. However, their potential association with the development of DCI remains elusive. In this study, we investigated the pattern of changes of different transcranial Doppler (TCD)-derived indices of cerebrovascular dynamics during vasospasm in patients suffering from subarachnoid hemorrhage, dichotomized by the presence of delayed cerebral ischemia. Methods: A retrospective analysis was performed using recordings from 32 SAH patients, diagnosed with VS. Patients were divided in two groups, depending on development of DCI. Magnitude of slow waves (SWs) of cerebral blood flow velocity (CBFV) was measured. Cerebral autoregulation was estimated using the moving correlation coefficient Mxa. Cerebral arterial time constant (tau) was expressed as the product of resistance and compliance. Complexity of CBFV was estimated through measurement of sample entropy (SampEn). Results: In the whole population (N = 32), magnitude of SWs of ipsilateral to VS side CBFV was higher during vasospasm (4.15 ± 1.55 vs before: 2.86 ± 1.21 cm/s, p < 0.001). Ipsilateral SWs of CBFV before VS had higher magnitude in DCI group (N = 19, p < 0.001) and were strongly predictive of DCI, with area under the curve (AUC) = 0.745 (p = 0.02). Vasospasm caused a non-significant shortening of ipsilateral values of tau and increase in SampEn in all patients related to pre-VS measurements, as well as an insignificant increase of Mxa in DCI related to non-DCI group (N = 13). Conclusions: In patients suffering from subarachnoid hemorrhage, TCD-detected VS was associated with higher ipsilateral CBFV SWs, related to pre-VS measurements. Higher CBFV SWs before VS were significantly predictive of delayed cerebral ischemia. [ABSTRACT FROM AUTHOR]

Neural processing occurs across a range of temporal scales. To facilitate this, the brain uses fast-changing representations reflecting momentary sensory input alongside more temporally extended representations, which integrate across both short and long temporal windows. The temporal flexibility of these representations allows animals to behave adaptively. Short temporal windows facilitate adaptive responding in dynamic environments, while longer temporal windows promote the gradual integration of information across time. In the cognitive and motor domains, the brain sets overarching goals to be achieved within a long temporal window, which must be broken down into sequences of actions and precise movement control processed across much shorter temporal windows. Previous human neuroimaging studies and large-scale artificial network models have ascribed different processing timescales to different cortical regions, linking this to each region’s position in an anatomical hierarchy determined by patterns of inter-regional connectivity. However, even within cortical regions, there is variability in responses when studied with single-neuron electrophysiology. Here, we review a series of recent electrophysiology experiments that demonstrate the heterogeneity of temporal receptive fields at the level of single neurons within a cortical region. This heterogeneity appears functionally relevant for the computations that neurons perform during decision-making and working memory. We consider anatomical and biophysical mechanisms that may give rise to a heterogeneity of timescales, including recurrent connectivity, cortical layer distribution, and neurotransmitter receptor expression. Finally, we reflect on the computational relevance of each brain region possessing a heterogeneity of neuronal timescales. We argue that this architecture is of particular importance for sensory, motor, and cognitive computations.

Super ionic channel or shuttle correlated with interfacial engineering of nanocomposite structure and semiconductor-based material electrolytes has shown great potential in electrochemical applications, such as photochemical water splitting or low temperature advanced fuel cell. By adjusting apriority composition between n and p components, the up-to-date semiconductor-ionic membrane fuel cells (SIMFCs) exhibit the improved performance, especially for high ionic conductivity and power outputs at lower temperature. Facing the commercialization of novel advanced ceramic cells, a combined literature survey and phenomenological analysis is proposed to interpret the difference between the current-voltage curve and stability performance of low temperature solid oxide fuel cell (LTSOFC). Meanwhile, it is experimentally determined that the time constant, which is closely related to the interfacial structure and heterostructure, has played a great role in the cell properties. Herein, steady state instead of transient characteristic is preferred, dedicating to provide much more reliable data. Among several prototype cells on semiconductor-based electrolyte, only the candidate that can resist the high current operation shows suppressing inside electronic leakage and survives in short-term test. The results illustrate that though semiconductor-based nanocomposite or heterostructure is an effective methodology in developing low temperature ceramic fuel cells, its durability and the risk of short-circuit should be taken with much care. • Difference between stability and common I–V characteristic is firstly revealed. • Concept of time constant and its influence on the I–V curve. • A revised polarization loss equation as a function of sampling time is constructed. • Time-correlated structure and interfacial evolvement of nanocomposite is stated. • Stable characteristic of polarization curve is more indicative of cell property. [ABSTRACT FROM AUTHOR]

The residual flux measurement is one of the difficulties in the transformer research field. This article presents a residual flux density (${B} _{\mathrm {r}}$) measurement method considering the relative differential permeability ($\mu _{\mathrm {rd}}$) of the core material. First, the basic relationship between $\mu _{\mathrm {rd}}$ and ${B} _{\mathrm {r}}$ is analyzed on the basis of the magnetic domain theory. Then, combining the experimentally measured relationship between ${B} _{\mathrm {r}}$ and $\mu _{\mathrm {rd}}$ , using $\mu _{\mathrm {rd}}$ as an intermediate variable, the relationship between ${B} _{\mathrm {r}}$ and time constant is derived. Furthermore, a square iron core model is established by the finite-element method, and the empirical formula for calculating ${B} _{\mathrm {r}}$ is was fit. Finally, the feasibility of this method and the accuracy of the proposed empirical formula are verified through experiments. [ABSTRACT FROM AUTHOR]

Neural processing occurs across a range of temporal scales. To facilitate this, the brain uses fast-changing representations reflecting momentary sensory input alongside more temporally extended representations, which integrate across both short and long temporal windows. The temporal flexibility of these representations allows animals to behave adaptively. Short temporal windows facilitate adaptive responding in dynamic environments, while longer temporal windows promote the gradual integration of information across time. In the cognitive and motor domains, the brain sets overarching goals to be achieved within a long temporal window, which must be broken down into sequences of actions and precise movement control processed across much shorter temporal windows. Previous human neuroimaging studies and large-scale artificial network models have ascribed different processing timescales to different cortical regions, linking this to each region's position in an anatomical hierarchy determined by patterns of inter-regional connectivity. However, even within cortical regions, there is variability in responses when studied with single-neuron electrophysiology. Here, we review a series of recent electrophysiology experiments that demonstrate the heterogeneity of temporal receptive fields at the level of single neurons within a cortical region. This heterogeneity appears functionally relevant for the computations that neurons perform during decision-making and working memory. We consider anatomical and biophysical mechanisms that may give rise to a heterogeneity of timescales, including recurrent connectivity, cortical layer distribution, and neurotransmitter receptor expression. Finally, we reflect on the computational relevance of each brain region possessing a heterogeneity of neuronal timescales. We argue that this architecture is of particular importance for sensory, motor, and cognitive computations. [ABSTRACT FROM AUTHOR]

Processes including one or more integrators in their transfer functions can frequently be encountered in industry. In this study, integral–proportional–derivative (I‐PD) controllers are proposed to control these type of processes. Analytical and optimal tuning rules are derived to tune the I‐PD controllers for setpoint tracking of integrating plus first order plus dead time (IFOPDT) processes and double IFOPDT processes. Optimal tuning rules for setpoint tracking are achieved by minimising time moment weighted integral performance criteria. Obtained I‐PD tuning formulas are in terms of process' transfer function parameters, namely the gain, time delay and time constant. Simulation examples are given to demonstrate the use of the proposed method. Comparisons are provided to show the superior closed‐loop performance of the proposed approach than existing proportional–integral–derivative and I‐PD controller designing methods. In addition, the practical implementation of the proposed designing method is presented by controlling the position of a cart on an experimental setup. [ABSTRACT FROM AUTHOR]

As traditional detecting method cannot accurately judge the moisture content in the oil-paper insulation system of the transformer, this paper discusses this problem from the viewpoint of the relationship between the return voltage and the equivalent circuit parameter based on the time domain dielectric spectrum theory and the extended-Debye equivalent circuit model． A criterion for determining the number of polarized branches of a transformer’s equivalent circuit was proposed with the method of micro-decomposition of the return voltage spectrum． Then the polarization equivalent circuit which can accurately reflect the aging state of oil-paper insulation transformer was constructed, and the relationship was studied between moisture content in the transformer and time constant of the polarization equivalent circuit by using the polarization equivalent circuit parameters of the transformers in different aging states． Finally, the average time constant for quantitatively analyzing moisture content in the transformer was proposed． Research results show that the moisture content in the transformer mainly affect the large time constant branches of the equivalent circuit, and the transformer moisture content can be quantitatively analyzed with the average time constant． It also shows that the value of moisture content is 1． 5%, 2%, and 3% respectively while the average time constant reach to 52． 12s, 21． 77 s, and 3． 98 s． As traditional detecting method cannot accurately judge the moisture content in the oil-paper insulation system of the transformer, this paper discusses this problem from the viewpoint of the relationship between the return voltage and the equivalent circuit parameter based on the time domain dielectric spectrum theory and the extended-Debye equivalent circuit model． A criterion for determining the number of polarized branches of a transformer’s equivalent circuit was proposed with the method of micro-decomposition of the return voltage spectrum． Then the polarization equivalent circuit which can accurately reflect the aging state of oil-paper insulation transformer was constructed, and the relationship was studied between moisture content in the transformer and time constant of the polarization equivalent circuit by using the polarization equivalent circuit parameters of the transformers in different aging states． Finally, the average time constant for quantitatively analyzing moisture content in the transformer was proposed． Research results show that the moisture content in the transformer mainly affect the large time constant branches of the equivalent circuit, and the transformer moisture content can be quantitatively analyzed with the average time constant． It also shows that the value of moisture content is 1． 5%, 2%, and 3% respectively while the average time constant reach to 52． 12s, 21． 77 s, and 3． 98 s． [ABSTRACT FROM AUTHOR]

The caloric step stimulus test consists of the changes in head position from the sitting to supine positions and continuous caloric irrigation. This test can provide a single labyrinth with a stimulus similar to constant head acceleration in rotational testing and, therefore, can evaluate vestibulo-ocular reflex (VOR) dynamics more precisely than can conventional methods. To assess the clinical utility of the test in the assessment of the VOR dynamics of diseases, we performed the test in patients with peripheral vestibular disorders, including sudden idiopathic hearing loss, vestibular neuritis, Meniere disease, vestibular Meniere disease, or chronic unilateral idiopathic vestibulopathy and normal controls. Slow-phase eye velocity (SPV) was measured with videonystagmography. We fitted the time course of SPV across 2 min to a mathematical model containing two exponential components and time constants: the caloric step VOR time constant (T1) and caloric step VOR adaptation time constant (T2). All responses of normal controls (n = 15 ears) were fit to the model. Several responses of the 101 ears of the patients differed from the time courses predicted by the model. We divided the data of 116 ears into four patterns based on SPV, T1, and T2. The thresholds for the classification were determined according to the lower limits of the capability of curve fitting for SPV and the upper limits of normal controls for T1 and T2. Seventy-eight ears followed pattern A (normal T1 and T2): the SPV trajectory formed a rapid rise with subsequent decay. Nineteen followed pattern B (normal T1 and prolonged T2): the SPV trajectory formed a rapid rise without decay. Six followed pattern C (prolonged T1 and T2): the SPV trajectory formed a slow rise. Thirteen ears followed pattern D: a low VOR response. There were no significant differences in time constants between the affected and healthy ears in patients with each disease. However, prolonged T1 and T2 were significantly more frequent in the affected ears than the healthy ears. In conclusion, the caloric step stimulus test can be potentially useful in detecting unusual VOR responses and thus reflect some pathological changes in the vestibular system.

The aim of the article is to describe the convective cooling of the measured samples and the subsequent processing of the measured to determine the material parameters of the solids in order to develop specialized software. In engineering practice, specifically in the field of materials research, it is necessary to measure the thermal properties of the materials under study. For a variety of materials, which may constitute the substitute for metals, such as steel, alloy, and others, including polymers and composites—especially for the newly developed materials, the table values of these parameters are not available. However, they are important to establish the thermal insulation properties of these materials, for further use in relevant industries. The time constant that determines the rate of cooling of the preheated sample is the basis for determining the additional thermal and technical parameters of the material. Based on the knowledge of the specific heat capacity, after specifying the range of the thermal diffusivity and thermal conductivity of the material, these parameters can be estimated. In order to estimate the coefficients, the non-linear parameter estimation methods can be used, which lead to the iterative calculations. A good candidate for these calculations is the MATLAB program, especially its CurveFitting toolbox. The price of Matlab SW, including CurveFitting Toolbox, is relatively high in terms of using the solution for this purpose. This resulted in the designing of new methods for CurveFitting described in this paper and implemented in the developed program named CurveFit.

Technologies for processing of digital signals find broad application in all spheres of the human activity, including agriculture. Further perfecting of these technologies is related to increasing of resolving power in analogue-to-digital and digital-to-analogue converters, requiring the improvement of quality indicator of the reference voltage sources such as noise level. This paper presents the possibilities for level reduction of output noise of the reference voltage sources. Circuit solutions of the single-stage and twostage, unipolar and bipolar low-noise sources of stable voltage of direct current produced on the basis of standard integral chips of voltage stabilizers are observed. The proposed circuit solutions provide reduction of output noise level of the reference voltage sources to the level of intrinsic noise of the operational amplifiers, which are part of the developed devices. It should be emphasized that single-stage unipolar low-noise sources of stable voltage of direct current are characteristic by the inversion of output voltage polarity that takes place in accordance with the polarity of output voltage of voltage stabilizer integral chip.

The caloric step stimulus test consists of the changes in head position from the sitting to supine positions and continuous caloric irrigation. This test can provide a single labyrinth with a stimulus similar to constant head acceleration in rotational testing and, therefore, can evaluate vestibulo-ocular reflex (VOR) dynamics more precisely than can conventional methods. To assess the clinical utility of the test in the assessment of the VOR dynamics of diseases, we performed the test in patients with peripheral vestibular disorders, including sudden idiopathic hearing loss, vestibular neuritis, Meniere disease, vestibular Meniere disease, or chronic unilateral idiopathic vestibulopathy and normal controls. Slow-phase eye velocity (SPV) was measured with videonystagmography. We fitted the time course of SPV across 2 min to a mathematical model containing two exponential components and time constants: the caloric step VOR time constant (T 1) and caloric step VOR adaptation time constant (T 2). All responses of normal controls (n = 15 ears) were fit to the model. Several responses of the 101 ears of the patients differed from the time courses predicted by the model. We divided the data of 116 ears into four patterns based on SPV, T 1, and T 2. The thresholds for the classification were determined according to the lower limits of the capability of curve fitting for SPV and the upper limits of normal controls for T 1 and T 2. Seventy-eight ears followed pattern A (normal T 1 and T 2): the SPV trajectory formed a rapid rise with subsequent decay. Nineteen followed pattern B (normal T 1 and prolonged T 2): the SPV trajectory formed a rapid rise without decay. Six followed pattern C (prolonged T 1 and T 2): the SPV trajectory formed a slow rise. Thirteen ears followed pattern D: a low VOR response. There were no significant differences in time constants between the affected and healthy ears in patients with each disease. However, prolonged T 1 and T 2 were significantly more frequent in the affected ears than the healthy ears. In conclusion, the caloric step stimulus test can be potentially useful in detecting unusual VOR responses and thus reflect some pathological changes in the vestibular system. [ABSTRACT FROM AUTHOR]

A novel system to measure the time constant of microbolometer cameras per-pixel to create a 2-D time constant map is presented. The measurements take place at the camera level and do not require any special control of the camera beyond the ability to capture raw data. Detailed simulations are run for a broad range of variables and values to demonstrate the usefulness of the system in extracting even extremely fast time constants with high accuracy and repeatability. Measurements are taken on a proof of concept system with an example camera, and a 2-D time constant map is reported. These results are compared with measurements from a linear motion stage system. [ABSTRACT FROM AUTHOR]

We consider the so-called frog model with random initial configurations, which is described by the following evolution mechanism of simple random walks on the multidimensional cubic lattice: Some particles are randomly assigned to any site of the multidimensional cubic lattice. Initially, only particles at the origin are active and they independently perform simple random walks. The other particles are sleeping and do not move at first. When sleeping particles are hit by an active particle, they become active and start doing independent simple random walks. An interest of this model is how initial configurations affect the asymptotic shape of the set of all sites visited by active particles up to a certain time. Thus, in this paper, we prove continuity for the asymptotic shape in the law of the initial configuration. [ABSTRACT FROM AUTHOR]

Automatic gain control (AGC) compresses the wide dynamic range of sounds to the narrow dynamic range of hearing-impaired listeners. Setting AGC parameters (time constants and knee points) is an important part of the fitting of hearing devices. These parameters do not only influence overall loudness elicited by the hearing devices but can also affect the recognition of speech in noise. We investigated whether matching knee points and time constants of the AGC between the cochlear implant and the hearing aid of bimodal listeners would improve speech recognition in noise. We recruited 18 bimodal listeners and provided them all with the same cochlear-implant processor and hearing aid. We compared the matched AGCs with the default device settings with mismatched AGCs. As a baseline, we also included a condition with the mismatched AGCs of the participants' own devices. We tested speech recognition in quiet and in noise presented from different directions. The time constants affected outcomes in the monaural testing condition with the cochlear implant alone. There were no specific binaural performance differences between the two AGC settings. Therefore, the performance was mostly dependent on the monaural cochlear implant alone condition. [ABSTRACT FROM AUTHOR]

This paper presents a new insulation resistance calculation technique to prevent electric shock and fire accidents due to the dielectric breakdown in the primary insulation section of the IT ground system. The solar power generation market is growing rapidly due to the recent expansion of renewable energy and energy storage systems, but as the insulation is destroyed and fire accidents frequently occur, a device for monitoring the insulation resistance state is indispensable to the IT grounding method. Compared to the conventional algorithm that use a method of multiplying a time constant to a fixed coefficient, the proposed insulation resistance calculation method has a fast response time and high accuracy over a wide insulation resistance range by applying a different coefficient according to the values of the insulation impedance. The proposed dynamic time constant based insulation resistance calculation technique reduces the response time by up to 39.29 seconds and improves the error rate by 20.11%, compared to the conventional method. [ABSTRACT FROM AUTHOR]

To monitor variations of blood samples effectively, it is required to quantify static and dynamic properties simultaneously. With previous approaches, the viscosity and elasticity of blood samples are obtained for static and transient flows with two syringe pumps. In this study, simultaneous measurement of pressure and equivalent compliance is suggested by analyzing the velocity fields of blood flows, where a blood sample is delivered in a periodic on-off fashion with a single syringe pump. The microfluidic device is composed of a main channel (mc) for quantifying the equivalent compliance and a pressure channel (pc) for measuring the blood pressure. Based on the mathematical relation, blood pressure at junction (Px) is expressed as Px = kβ. Here, β is calculated by integrating the averaged velocity in the pressure channel (pc>). The equivalent compliance (Ceq) is then quantified as Ceq = λoff · Q0/Px with a discrete fluidic model. The time constant (λoff) is obtained from the transient behavior of the averaged blood velocity in the main channel (mc>). According to results, Px and Ceq varied considerably with respect to the hematocrit and flow rate. The present method (i.e., blood pressure, compliance) shows a strong correlation with the previous method (i.e., blood viscosity, elasticity). In conclusion, the present method can be considered as a potential tool for monitoring the mechanical properties of blood samples supplied periodically from a single syringe pump. [ABSTRACT FROM AUTHOR]

Background/Objective: Slow-Phase Eye Velocity Time constant (SPEV TC) and Perceived Rotational Duration (PRD) are measurable objective outcomes of rotational chair step-velocity test. These two variables are dependent on the efficacy of the central velocity storage. If sensory conflict from the step-velocity of the rotational chair elicits motion sickness, the SPEV TC and PRD in individuals with varying susceptibility to motion sickness should be affected. We determined if Central Vestibular Sensitivity (CVS) characteristics differ among individuals with a range of Motion Sickness Susceptibility (MSS). Methods: Participants were allocated to two groups based on MSS (low and high) as identified on the short version of the Motion Sick Susceptibility Questionnaire (MSSQ-S). We evaluated the specific relationship between MSS and the characteristics of CVS through the SPEV TC and PRD from the step-velocity test. Results: Results showed significant differences in the PRD between these two groups. 180°/s Per-rotatory PRD is most significantly different (p = 0.005) followed by 50°/s post-rotatory PRD (CCW, p = 0.007; CW, p = 0.021) and log of 180°/s post-rotatory PRD (p = 0.042). Multiple regression analysis indicated that CCW post-rotatory PRD at 50°/s was a strong predictor of MSS. Conclusions: High MSS individuals were observed with elevated PRD in general, indirectly suggesting greater velocity storage efficiency, hence, greater CVS; CVS is therefore positively correlated with MSS. PRD could be a reliable clinical indicator of motion sick susceptibility and may help with the selection of personnel working in motion sick environments and with the verification of motion sickness therapeutic interventions. [ABSTRACT FROM AUTHOR]

In AC/DC converter transformers under DC application, the electric field distributions are distorted due to the accumulated charge on pressboard. However, the time‐dependent characteristics of DC electric field stress in oil has not yet been clarified in detail. In this paper, we investigated the time and electric field space transition characteristics of DC electric field distributions in oil‐pressboard composite insulation systems. As a result, we quantitatively clarified that DC electric field stress strongly depends on the elapsed time and the location in the electric field space in oil. In particular, it was found that the most severe electric field stress in oil may emerge during the time transition process. [ABSTRACT FROM AUTHOR]

The development of digital technologies that are widely used in industry and agriculture places high demands on voltage reference sources for a number of parameters, each of which is important in its own way. However, a further increase in the resolution of analog-to-digital and digital-to-analog converters and, therefore, of all digital signal processing is impossible without an improvement in such a quality indicator of reference voltage sources as the noise level. In this paper, we discuss the method and schematic solution of designing a low-noise source of stable dc voltage base on standard integrated circuits of voltage stabilizers. The schematic solution provides an ability to reduce the output noise level of the corresponding reference voltage sources to a level slightly higher than the intrinsic noise level of operational amplifiers used as a part of the device block circuits, maintaining the polarity and stability of the device output voltage relative to the output voltage of the used integrated circuit of a voltage stabilizer, and reduction in capacitance of used capacitors compared with known circuit solutions. [ABSTRACT FROM AUTHOR]

The long-term sustainable development of mineral exploration under covers require effective deep detection techniques and methods. Start from enhancing the surface-borehole time-domain electromagnetic (TEM) technique, the present study established a new relationship between the pulse width (Δ), the target time constant (τ) and the measurement time (t). Under certain conditions, the new formula has been extended to all TEM systems that use square or trapezoidal waveforms. A series of numerical simulations illustrate the consistent behaviors of the surface-borehole, ground and airborne TEM fields. The new relationship allows us to evaluate optimal pulse widths for different off-times and to help TEM survey design. [ABSTRACT FROM AUTHOR]

The K, E, and J-types of coaxial thermocouples have been designed and fabricate to perform transient heat flux evaluation at the combustion chamber of a four-stroke diesel engine. These coaxial thermocouples are quite efficient in short-duration transient measurements due to the response time of these instruments are in the rage of milliseconds or less. Using water plunging technique, the thermal product and time constant of these handmade coaxial thermocouples have been evaluated as well as compared with available literatures. The transient temperature signals are recorded form K, E, and J-type coaxial thermocouples on the combustion chamber of a four-stroke internal combustion engine for short duration of 200 ms. The transient heat fluxes are acquired from transient temperature signals with the help of one-dimensional heat conduction formulation for a semi-infinite solid body. The errors in the estimated heat flux and transient temperature have been observed as 3% and 0.5 %, respectively, which are relatively small and acceptable. This signifies that the heat flux values are depending upon the temperature measured by coaxial thermocouple junction as well as also depending on time rate. This survey asserts the heat flux measurement capability of coaxial thermocouple during the combustion process on the internal combustion chamber of a four-stroke diesel engine. [ABSTRACT FROM AUTHOR]

Purpose. The purpose of the article is to study the rational operation of the hot-wire anemometer in accordance with the dynamic characteristics and measurement errors, when implementing the process of drying raw nuts in an industrial microwave chamber. Methodology. The technique of studying the informative parameters of the heat flow was used to determine the rational mode of operation of the hot-wire anemometer and to reduce the time of heat treatment of nut raw materials. Results. The characteristics of the thermal transient process of drying raw nut materials in a microwave chamber are investigated. Theoretical substantiation and an algorithm for determining the dynamic characteristics of the hot-wire anemometer under the external sinusoidal effect of the heat flow temperature are given, algorithms for determining the instantaneous values of the temperature increments of the hot-wire anemometer sensitive element in the process of drying nut raw materials are given. On the basis of the general theory of errors of indirect measurements in the investigated range of variation of the rate V of the heat flow, the values of the relative systematic errors of indirect measurements of the rate of heat flow in the range from 10 to 40 m / s were determined. It was found that in accordance with the dynamic characteristics and measurement errors when blowing a moving heat flow of nut raw materials, the most rational is the mode of constant resistance of the hot-wire anemometer. Solutions of the differential equation describing the dynamic heat process when the temperature of the moving heat flow changes according to the periodic law, i.e. stationary, non-stationary and complete. The results of calculating the constant times of the hot-wire anemometer thread τп and τmп of the moving heat flow, respectively, were τп = 0.59 s and τmп = 0.6 s, the time constant of the hot-wire anemometer is practically commensurate with the thermal time constant of the moving stream blowing over the nut raw material. Scientific novelty. It consists in the fact that the theoretical position of the hot-wire anemometer has been further developed in the direction of researching the characteristics of the thermal transient process of processing nut raw materials, all this makes it possible to determine the ranges of changes in the signals of the thermal device, which correspond to the ranges of change in the informative characteristics of the moving heat flow, and also allows the selection measuring equipment, establish rational operating modes of hot-wire anemometers and automated devices that use them in accordance with errors and sensitivities. Practical value. The proposed algorithms for determining the informative parameters of the heat flow in the study of the transient process of heat transfer from the moving air flow to the sensitive element of the transducer, the results of the errors in measuring the velocity V of the moving heat flow, make it possible to calculate, design and create measuring automated devices that use hot-wire anemometers in food and processing industry, instrument making and chemical engineering. [ABSTRACT FROM AUTHOR]

Building dynamics are key to summer overheating, plant sizing and ventilation strategies. Building designers need to consider the thermal mass of a building explicitly to understand fully a building's response. Simulation programs readily show the dynamic responses but they are deduced from the solution of embedded intrinsic differential equations without simple understanding for initial design and appreciation. The admittance method gives such a simple understanding but the thermal mass effects are not obvious. Added to which the admittance is limited to a regular 24 h cycles of heat gains and losses. The Chartered Institution of Building Services Engineers (CIBSE) response factor is an approximation to the response of a building but it is limited to defining just slow or fast responses. Frequently, designers refer to heavyweight and lightweight buildings or even long and short time constants. The latter are simple and understandable. This paper explores the time constants and derives a simple multiple time constant equation to indicate thermal storage in a building. It is suggested that the simple time constant for building components is added to the data in the next edition of the CIBSE Guide A. This will aid designers in understanding a building's winter heating and potential summer overheating and plant size implications. [ABSTRACT FROM AUTHOR]

The transient, axisymmetric squeeze flow of the non-Newtonian shear thinning material between finite disks is studied numerically. The fluid between disks is assumed to follow the Carreau-Bird model. Two disks approach each other at a constant velocity while no-slip boundary condition is assumed. The time dependent simulation shows the effect of fluid nonlinearity, flow parameters and geometric aspect ratio on the flow dynamic and evolution of squeeze force. Also, some physical phenomena are shown and are explained at the edge of the disks and out of them. The conservation and momentum equations containing inertia effects are solved using moving mesh scheme and finite volume method. The SIMPLE algorithm is used to solve the pressure-velocity coupling. [ABSTRACT FROM AUTHOR]

It is shown that the systematic error in determining the extent of a defect is mainly affected by two factors: the testing voltage across the gas-discharge defect sensor and the time constant of sensor's discharge circuit. It has ben established that the wire speed does not have significant effect on this error. The practical application of the established regularities to increasing the accuracy of monitoring the extent of defects in the insulation of a wire using defect meters with a gas discharge sensor is shown. [ABSTRACT FROM AUTHOR]

This paper presents the results of identifying the transient response of a relative air humidity sensor. It is shown that the capacitive relative humidity sensor is an integrated microprocessor system that performs joint processing of the readings of the absolute humidity sensor and the temperature sensor. A mathematical model of the relative humidity measurement process is proposed. The transient responses of the absolute humidity sensing element and the temperature sensor are specified under the assumption that they correspond to first-order aperiodic factors. Based on the relationships of thermodynamics, Arden Buck equation, and given transient functions, analytical dependencies are obtained to identify the parameters of the transient response of the capacitive relative humidity sensor. The results of several field experiments are processed and analyzed in accordance with the proposed mathematical model. The effect of anomalous sensor readings is revealed and consists in the fact that with simultaneous stepwise changes in humidity and temperature, the sensor records a change in relative humidity with the opposite sign. It has been established that the cause of the anomalous results of relative humidity measurements is the presence of a large difference between the response time constant of the absolute humidity sensing element and that of the temperature sensor. Measures are proposed to prevent anomalous results of relative humidity measurements. [ABSTRACT FROM AUTHOR]