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Purpose: To examine the impact of oral contraceptive (OC) phases on performance, physiological, and subjective responses to prolonged, intensive exercise when carbohydrate (CHO) stores are reduced. Methods: Ten well-trained female cyclists using monophasic OC completed 4 identical trials (>150 min) under conditions of in-trial 60-g·h−1 CHO supplementation (CHO+) or placebo (CHO−) during the sugar- (SUG) and active-pill (ACT) phases of their OC cycle. Each trial comprised two 400-kcal time trials (TT) separated by 1 hour of submaximal cycling at first ventilatory threshold. Results: Change in completion time from TT1 to TT2 was minimized in CHO+ compared with CHO− (4.06 [2.55] vs 6.08 [5.33] min; P =.019, effect size = −0.36). An interaction effect of OC and CHO was observed for time to complete TT (P =.006), mean TT power (P =.002), mean TT heart rate (P =.002), and posttrial emotional balance (P =.020) and negative emotional state (P =.033). In ACT, mean TT power and heart rate were higher in CHO+ when compared with CHO−, resulting in faster TTs in CHO+ and improved posttrial emotional well-being. When CHO was not supplemented, TT power and heart rate were higher in SUG when compared with ACT, resulting in faster TTs in SUG and improved posttrial emotional balance. Conclusion: CHO depletion during ACT negatively influenced TT performance and emotional well-being when compared with SUG. Irrespective of OC pill phase, CHO supplementation should be prioritized to sustain performance and improve postexercise recovery–stress balance. [ABSTRACT FROM AUTHOR]

The seismic performance of a caisson structure under two types of models with a saturated sandy foundation (CSS) and an expanded polystyrene (EPS) composite soil foundation (CES) are studied using shaking table tests. The macro phenomena of the two different foundation models are described and analyzed. The effects of the replacement of EPS composite soil on seismic-induced liquefaction of backfill and the dynamic performance of a caisson structure are evaluated in detail. The results show that the excess pore water pressure generation in the CES is significantly slower than that in the CSS during the shaking. The dynamic earth pressure acting on the caisson has a triangular shape. The response of horizontal acceleration, displacement, settlement, and rotation angle of the caisson in the CES is smaller than that in the CSS, which means the caisson in the CES has a better seismic performance. Furthermore, the out-of-phase phenomenon between dynamic earth thrust and inertial force in the CES is more obvious than that in the CSS, which is beneficial to reduce the lateral force and improve the stability of the caisson structure. [ABSTRACT FROM AUTHOR]

Structures with a partially overlapped status in water can be seen in some engineering applications, and the fluid-structure coupling vibration behavior of two partially overlapped identical plates has been studied previously through the experimental method. In this study, the added damping of the T(0,1) modes of two submerged partially overlapped plates is numerically investigated through the one-way fluid-structure interaction (FSI) method. The relevant numerical settings, like the mesh size, calculated periods, time-step size, and vibration amplitude, were tested first. Then, the numerical results were compared with experimental results, and good agreements were found. Finally, numerical results were analyzed. The vibration status of two plates in the joint abutting area or the overlapped area has an important influence on the added mass variation. When the added mass is higher, the phase difference between modal force and vibration displacement is also greater, which is the main reason for the higher added damping. The relationship between the phase difference and the frequency in water can be approximately fitted to a straight line, which can probably be used to predict the added damping variations caused by fluid boundary changes of submerged structures. [ABSTRACT FROM AUTHOR]

We show how the quantum hydrodynamical formulation of quantum mechanics converts the nonlocality in the standard wave-like description of quantum systems by an instability of the quantum system, which opens the door to a new way for studying quantum systems based on known methodologies for studying the stability of fluids. As a second result, we show how the Madelung equations describe quantized energies without any external quantization conditions. [ABSTRACT FROM AUTHOR]

Phase‐based light detection and ranging (LiDAR) technology is emerging in the fields of industrial mapping, autonomous driving, and robotics, but the traditional phase‐based ranging technology generally suffers from the problem that the ranging accuracy is inversely proportional to the measurement range under a single measurement frequency, the system structure is complicated, and the performance is unstable, and so forth. In this article, a new type of LiDAR system design based on phase ranging is proposed. The system adopts a 100 + 1 MHz double measuring ruler modulation light source, uses the laser to control the phase difference detection method of the same frequency reference, optimizes the structure of the transceiver optical system, and the design of AD8302 high‐resolution signal phase discriminator circuit, builds a high‐precision laser ranging system, and carries out the experiments on the measurement accuracy of the LiDAR ranging system. The experimental results show that the measurement accuracy of the system is millimeter level, which is simple, practical, and can meet the needs of a wide range of practical applications. This study provides a feasible and innovative solution for LiDAR technology in high‐precision distance measurement. [ABSTRACT FROM AUTHOR]

In this paper, different cutting edge curve models of ellipsoid end milling cutter are presented. The cutting edge models of ellipsoid end milling cutter in milling process are established by taking initial phase difference, feed per tooth and cutting direction as variables. Based on the Z-Map algorithm, the spatial point cloud data of the surface topography of secondary milling were obtained, and the visual simulation was carried out based on the point cloud data. The influence of milling parameters on the surface topography characteristics was analyzed, and the simulation model was verified by the secondary milling experiment. The results show that the feed per tooth and cutting direction have significant influence on the simulation of surface topography in secondary milling. The simulation model of secondary milling and the corresponding conclusions provide a theoretical basis for predicting the surface topography of the work-piece prepared by the cutting edge of ellipsoid end milling cutter. [ABSTRACT FROM AUTHOR]

Abstract We analyzed electrostatic electron cyclotron harmonic waves observed by the interferometry observation mode of the Arase satellite. It is found that the magnitude of the phase difference varies with the satellite spin. The spin dependence of this phase difference was investigated by examining the trend of the spin dependence for the 84 events of interferometry observation of ECH waves. We found that they are divided into two categories. One is that the phase difference tends to show sinusoidal variations as a function of the angle $$\gamma _B$$ γ B between the ambient magnetic field projected on the spin plane and the electric field sensor. The other is that the phase difference is close to zero and does not depend on $$\gamma _B$$ γ B . A numerical model of interferometry observation of single plane wave is constructed to explain the observed phase differences. We performed the numerical calculations when the background magnetic field was oriented in the direction often observed in the Arase satellite. The result of the calculations shows the wave vector direction relates to the spin angle with the maximum phase difference. Using this relation, we show that it may be possible to estimate the wave vector direction of ECH waves from one-dimensional interferometry data. This is expected to enable more accurate estimates of phase velocity. Graphical Abstract

Self‐excited thermoacoustic instability (SETAI) is a dangerous phenomenon in combustion equipment. While it is widely acknowledged that SETAI behavior is determined by the couple between pressure and heat release oscillation, their phase difference is difficult to predict, which impedes the development of SETAI control technology. With the aim of passive control technology development, this paper conducted experiment on a premixed hedge combustor to explore the mechanism whereby premixed chamber length (LP) and equivalence ratio (φ) collaboratively influence SETAI behavior. Results showed LP mainly affects the pressure mode shape within premixed chamber and consequently alters the phase difference between pressure and flowrate oscillation at combustion chamber inlet. Changing φ gives rise to different reaction time‐lag (τ), thus altering the phase difference between flowrate and reaction heat release oscillation. By introducing this flowrate oscillation, how LP and φ collaboratively determine phase difference between pressure oscillation and heat release oscillation was clarified. The mechanisms identified in this study are consistent with the emerging rationalization of the factors contributing to SETAI, and also provides better understanding on Rayleigh criterion and guidance for SETAI control. With further work on heat release and flow rate measurement, as well as the development on τ description, SETAI can be better predicted and controlled. [ABSTRACT FROM AUTHOR]

We analyzed electrostatic electron cyclotron harmonic waves observed by the interferometry observation mode of the Arase satellite. It is found that the magnitude of the phase difference varies with the satellite spin. The spin dependence of this phase difference was investigated by examining the trend of the spin dependence for the 84 events of interferometry observation of ECH waves. We found that they are divided into two categories. One is that the phase difference tends to show sinusoidal variations as a function of the angle γ B between the ambient magnetic field projected on the spin plane and the electric field sensor. The other is that the phase difference is close to zero and does not depend on γ B . A numerical model of interferometry observation of single plane wave is constructed to explain the observed phase differences. We performed the numerical calculations when the background magnetic field was oriented in the direction often observed in the Arase satellite. The result of the calculations shows the wave vector direction relates to the spin angle with the maximum phase difference. Using this relation, we show that it may be possible to estimate the wave vector direction of ECH waves from one-dimensional interferometry data. This is expected to enable more accurate estimates of phase velocity. [ABSTRACT FROM AUTHOR]

Frequency is one of the most significant indicators of power system, which needs accurate estimation to provide a reliable basis for monitoring, control, and protection. Owning to the efficiency, DFT is widely used in the frequency measurement of power systems. However, the inherent defects, that is, the spectral leakage and picket fence effect, decrease the accuracy of DFT. One of the variants, named the windowed phase difference method (WPD), addresses the problem using the phase variation of two windowed sequences in the frequency domain and achieves accurate frequency estimation. Suffering from the ignored negative component and contamination of noise, there are still undesired errors in WPD-based frequency estimation. To reduce the influence of the undesired errors, this paper first analyzes the systematic error of WPD introduced by spectrum leakage and proposes an improved WPD (IWPD) through systematic error compensation to achieve more accurate frequency estimations. Then, the windowing effect on IWPD-based frequency estimation of a noisy signal is studied by deducing the theoretical expression of frequency estimation variance. Finally, the proposed IWPD is validated by extensive computer simulations and practical experiments. [ABSTRACT FROM AUTHOR]

This study introduces a novel approach to enhance the thermal performance of a confined slot jet impingement system over a heated plate using multiple pulsating jets. By analyzing the complex fluid flow structure and transport phenomena, resulting from the interaction of the twin jets with the target surface, this research highlights three crucial factors: jet pulsation frequency, phase difference, and intermittent motion of the impingement plate. These factors disrupt the boundary layer, create favorable temperature and velocity gradients, and improve heat transfer rates. The velocity vector field analysis reveals the generation of vortices in multiple regions due to the coherent pulsatile jet. The study concludes that increasing the jet pulsation frequency beyond the critical value corresponding to a Strouhal number = 0.26 improves heat removal rate from the isothermal plate. Interestingly, the phase difference promotes heat transport only when the plate is stationary but loses its beneficial effect during intermittent motion. Phase difference results in a 6.7% improvement in average Nusselt number at a jet pulsation frequency of 40 Hz with a stationary plate, particularly benefiting lower frequency pulsating flows. Non-uniform plate motion exhibits the strongest influence on the heat transfer process among the investigated factors. Optimal thermal energy exchange requires careful adjustment of these factors. For instance, when both jet pulsation and intermittent plate motion frequencies are set to 100 Hz, convective heat transfer improves by up to 48% compared to the steady-state scenario, regardless of the phase difference. These findings may benefit the design and optimization of jet impingement-based thermal management systems. [ABSTRACT FROM AUTHOR]

Mainline coordinated control is usually based on fixed speed and statistical traffic flow by period. However, in actual operation, the vehicles parked in front of the intersection and the arriving vehicles often fluctuate, and the through-traffic green time is wasted due to phase transition, which leads to mismatches between the signal plans and actual traffic flow requirements, affecting the traffic efficiency of the intersection. To address the above issues, using vehicle–road collaborative control (VRCC), by calculating the phase difference lead time and phase difference of adjacent intersections, the green extension time for the green wave through-traffic phase, and the guiding vehicle speed, the goal of reducing the detention volume of through traffic, reducing the waste of through-traffic green time caused by phase transitions and improving the throughput of through traffic can be achieved. The speed of the green wave traffic flow is increased by guiding vehicles to form saturated platoons during green periods. Finally, PTV VISSIM 4.3 was used for simulation verification, and the results showed that compared to not implementing the control strategy, the average delay on the arterial road was reduced by 85.1%, the average number of stops was reduced by 84.3%, the average travel time was reduced by 34%, and the average queue length was reduced by 62.6%. This significantly improved the efficiency of traffic on the arterial road and effectively reduced congestion. [ABSTRACT FROM AUTHOR]

To measure the electrical parameters of 25Hz phase-sensitive track circuit, a testing instrument with STM32 microcontroller as the control core is designed. It mainly uses the method of root mean square and fast Fourier transform to measure the effective value of the coil voltage of the track relay and the phase difference between the coil voltage of the track relay and the local coil voltage. The voltage waveform and calculation results are displayed on TFT-LCD, which has the advantages of simple structure, fast processing speed and high measurement accuracy. It is convenient for the daily detection and fault diagnosis of 25Hz phase-sensitive track circuit. [ABSTRACT FROM AUTHOR]

This paper focus on synchronization of four eccentric rotors (ERs) with parallel and coplanar rotational axis in a single mass vibration system, distinct from planar systems. Utilizing the average method of small parameters, the coupling motion relation are established by introducing phase differences of four ERs. The synchronous condition is determined by estimating the differences in loading torque of four ERs. The coupling dynamic characteristics are discussed numerically from coupling torque and synchronous ability. Two synchronous motion states are identified theoretically and experimentally. The results indicate that four ERs approach to in-phase when the vibration system operates in the frequency region before resonance, causing the body to move in a straight line. Conversely, when four ERs approaches to anti-phase in frequency region after resonance, the mass center of the vibration system remains nearly stationary. These conclusions play a guiding role in the design of vibratory machinery. [ABSTRACT FROM AUTHOR]

In practical mechanical components, the characteristic of geometric discontinuous generates non‐uniform energy field near the notch, which affects the local damage evolution process of the notched specimens. Therefore, it is particularly crucial to formulate a parameter that can characterize such inhomogeneous state distribution. First, a strain energy density gradient factor is introduced to describe the complexity of strain energy density distribution near the notch. Meanwhile, a size effect factor is given considering the strain energy gradient factor and notch geometry parameter. Then, taking into account the impact of phase difference, a direct damage parameter considering non‐proportionality of different multiaxial load levels is developed. Furtherly, the modified strain energy density parameter is determined. Finally, the comparison between the proposed model and the other three models emphasizes the advantages of the model. Highlights: A strain energy density gradient factor is given for the fatigue analysis of notched specimens.A calculation method of equivalent strain energy density is proposed.Several key factors affecting the fatigue life of notched specimens are considered.A general procedure for fatigue life prediction of notched specimens is presented. [ABSTRACT FROM AUTHOR]

Oscillating water column (OWC) based wave energy absorption devices are classic which have been widely used for harnessing ocean wave energy. This paper presents a numerical study on a projecting wall (PW) type OWC wave energy converter in regular waves. The computational fluid dynamics (CFD) modelling of a stationary floating PW-OWC model in a three-dimensional wave flume is achieved by the software Flow-3D. Numerical analyses are carried out based on CFD simulations and the linear potential flow solutions with modifications to account for turbine-induced damping. The present numerical solutions are validated against our previous experimental data. It is found that both the CFD and modified linear potential flow predictions are in reasonably good agreements with the experimental data in the first order results of OWC and air pressure responses. When the nonlinear responses are included in the result, the modified linear potential flow solution is found to slightly under-estimate the wave energy conversion performance at long wavelengths. Regarding the airflows above and below the chamber orifice, the CFD results suggest that they are almost unidirectional, oscillating in not only the base frequency but also subharmonic and ultraharmonic frequencies. The evolution of the OWC responses during an entire period and the phase analysis based on CFD simulations are presented. The phase results provide the crucial evidence to the reasonability of the physics-based modification of the potential flow model in modelling of OWCs. The present results and analysis are expected to be beneficial to the understanding on the physical mechanism of OWCs and the design of phase control strategies. [ABSTRACT FROM AUTHOR]

In sound signal processing, angle of arrival indicates the direction from which a propagating sound signal arrives at a point where multiple omnidirectional microphones are positioned. Considering a small underwater platform (e.g., underwater unmanned vehicle), this article addresses how to estimate a non-cooperative target's signal direction utilizing the minimum number of omnidirectional microphones. It is desirable to use the minimum number of microphones, since one can reduce the cost and size of the platform by using small number of omnidirectional microphones. Suppose that each microphone measures a real-valued sound signal whose speed and frequency information are not known in advance. Since two microphones cannot determine a unique AOA solution, this study presents how to estimate the angle of arrival using a general configuration composed of three omnidirectional microphones. The effectiveness of the proposed angle of arrival estimator utilizing only three microphones is demonstrated by comparing it with the state-of-the-art estimation algorithm through computer simulations. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel cutting manner is presented to control regenerative chatter vibration in double inserts cutting, in which the forward and the backward inserts cut workpiece simultaneously with phase difference in the modulation of finished surface. In double inserts cutting, the forward insert is clamped above the backward insert. Both the inserts are positioned symmetrically with a height offset with respect to the workpiece rotation center. The forward insert mainly removes the material; while the backward insert cuts a part of the inner modulation to lose the regular excitation. The exciting force is also reduced with the cutting thickness of the forward insert after a workpiece revolution. Because the theoretical position offset of the inserts in the feed direction is small, the side cutting edges of inserts are aligned in the same position. The process parameters are determined by estimating the removal volume of the backward insert with the phase shift. The range of the cutting speed and the height offset are given by the frequency of the chatter vibration, which is nearly the same as the natural frequency of the workpiece in single degree of freedom. The proposed cutting manner is validated using comparison between the single insert and double inserts cuttings. [ABSTRACT FROM AUTHOR]

A 3D nano-displacement measurement method, where the difference in phase between the beams in a four-beam laser interference is changed, is proposed. Simulation results demonstrate that the variation of phase difference causes the deviation of the interference pattern in the laser interference system. Based on this theory, we design and build a four-beam laser interference system. The corner cube prism in the optical path is shifted, and the phase of the beam is changed by applying different voltages to a piezoelectric stage. The phase difference is obtained by analyzing the lattice pattern with subpixel precision, and then the displacement is determined by correlation operation. The experimental measurement results are consistent with the theoretical analysis, thereby verifying the feasibility of this measurement method. Highlights: The four-beam laser interference lattice pattern can achieve higher precision displacement measurement. The 3D displacement measurement system of the four-beam laser interference can realize single-dimensional or multi-dimensional displacement measurement. At the same time, it provides a basis for micro-displacement measurement in various applications. The specific pixels of the interference pattern are accurately located using the correlation operation to achieve precise measurement results and minimize errors. [ABSTRACT FROM AUTHOR]

This paper aims at investigating the synchronization of unbalanced rotors and rigid frames in a vibration system, consisting of three elastically connected rigid frames and two counter-rotating unbalanced rotors, which are mounted on different inner rigid frames. Using the Lagrange approach, the governing equations of motions are derived. Using the method of averaging, the existence condition of synchronization for two unbalanced rotors is determined. Applying Lyapunov stability theory, the condition of the system to get stable synchronous states is obtained. In order to analyze the selected motion characteristic of unbalanced rotors and rigid frames, numerical simulations are performed. Specifically, the phase difference between two unbalanced rotors and motion lag phases of rigid frames is studied by considering different synchronous frequencies and ratios of masses of unbalanced rotors. Furthermore, a series of experiments for different frequency regions of vibrations is carried out to validate the obtained theoretical results. The coupling motion characteristics of unbalanced rotors are studied by comparing the cases of excitation of a single and two unbalanced rotors. The present work and obtained results can serve as theoretical and experimental basis for the design of vibration jaw crushers in engineering. [ABSTRACT FROM AUTHOR]

Despite the widespread application of spur dikes in river training projects, the performance of the structure during flood events and its impacts on unsteady flow conditions have rarely been studied. In this experimental investigation, the influences of twelve unsubmerged unilateral and bilateral spur dike layouts on upstream flow conditions during flood movements were examined. Three hydrographs with varying unsteadiness intensities were generated and applied to all layout tests, including the no-spur condition for comparison purposes. The results revealed that discharge directly affected changes in flow depth upstream of the spur dike, while the flow rate trend exerted inverse influences. The Keulegan-Carpenter number was modified to assess the impact of unsteadiness intensity on the rating curve loop. Stage hysteresis analysis demonstrated an increase of more than thirty times compared to the no-spur scenario, highlighting the elevated risk of flooding in the upstream reach while delaying peak flood arrival time. This has implications for flood risk management and warning programs. The results underscore the significance of considering not only peak discharge but also unsteadiness intensity in spur dike design. [ABSTRACT FROM AUTHOR]

This article proposes a design method for a circularly-polarized (CP) antenna, which is realized by using coupling effects. Initially, the desired electric(magnetic) coupling between two identical $\lambda$ /4 short-circuited microstrip line (MS-L) resonators can be generated when the short-circuited (opencircuited) ends of the resonators are in close proximity to each other. Besides, an orthogonal arrangement in space for these two resonators has been adopted to yield two orthogonal linearly-polarized (LP) waves. Therefore, a desired CP rotation can be achieved by choosing corresponding coupling types. Meanwhile, two equivalent circuit models are established and analyzed to deduce the formulas of the mutual inductance and mutual capacitance for the desired CP radiation. Afterwards, a binary array consisting of a magnetically coupled (MC) pair of resonators and an electrically coupled (EC) pair of resonators is proposed for expanding the axial ratio bandwidth (ARBW) and enhancing peak gain. Finally, a right-handed circularlypolarized (RHCP) antenna with magnetic coupling, a left-handed circularly-polarized (LHCP) antenna with electric coupling and a binary array are fabricated and tested. And an excellent agreement is validated between the experiment and simulation results. The measured results show that the binary array achieves a maximum gain of 5 dBic within its measured ARBW range of 3.535 – 3.615 GHz. In contrast, the single pairs (EC or MC pair) exhibit a gain of 3 dBic. Additionally, the array demonstrates a fivefold expansion in ARBW compared to the single pair.

Orbit angular momentum (OAM) has been considered a new dimension for improving channel capacity in recent years. In this paper, a millimeter-wave broadband multi-mode waveguide traveling-wave antenna with OAM is proposed by innovatively utilizing the transmitted electromagnetic waves (EMWs) characteristic of substrate-integrated gap waveguides (SIGWs) to introduce phase delay, resulting in coupling to the radiate units with a phase jump. Nine "L"-shaped slot radiate elements are cut in a circular order at a certain angle on the SIGW to generate spin angular momentum (SAM) and OAM. To generate more OAM modes and match the antenna, four "Π"-shaped slot radiate units with a 90° relationship to each other are designed in this circular array. The simulation results show that the antenna operates at 28 GHz, with a −10 dB fractional bandwidth (FBW) = 35.7%, ranging from 25.50 to 35.85 GHz and a VSWR ≤ 1.5 dB from 28.60 to 32.0 GHz and 28.60 to 32.0 GHz. The antenna radiates a linear polarization (LP) mode with a gain of 9.3 dBi at 34.0~37.2 GHz, a l = 2 SAM–OAM (i.e., circular polarization OAM (CP–OAM)) mode with 8.04 dBi at 25.90~28.08 GHz, a l = 1 and l = 2 hybrid OAM mode with 5.7 dBi at 28.08~29.67 GHz, a SAM (i.e., left/right hand circular polarization (L/RHCP) mode with 4.6 dBi at 29.67~30.41 GHz, and a LP mode at 30.41~35.85 GHz. In addition, the waveguide transmits energy with a bandwidth ranging from 26.10 to 38.46 GHz. Within the in-band, only a quasi-TEM mode is transmitted with an energy transmission loss | S 21 | ≤ 2 dB. [ABSTRACT FROM AUTHOR]

One of the most important types of misalignments is crooked ball bearing rings. In this study, effects of crooked shaft washer related to a single-row thrust ball bearing on the system vibrating response have been investigated. For this purpose, a new dynamic model including 4-dof is considered for this bearing, housing and shaft mounted on it. Contact forces between rings and balls are described according to Hertzian equation. In the following, nonlinear Euler's equilibrium is used to describe dynamic motion of the rings solved by numerical method. It is shown that these responses contain frequencies and phases that support the specialized signature of crookedness of the shaft washer in thrust ball bearing. Verification of responses has been done by Ansys software. The effect of amount of crookedness in the shaft washer and external axial force on the responses have also been investigated. [ABSTRACT FROM AUTHOR]

A new piecewise function to determine the thickness profile of transparent thin films, is built from a piecewise scaled function of the 1D gray value plot obtained through monochromatic-light-interferometry. In the gray value piecewise function each subfunction contains the information of the physical phenomena related to fringe pattern formation and corresponds to an interferometric branch. The interference phenomenon is studied by assuming that the scaled function is the normalized intensity that comes from light interference in an infinite thin-layer material inserted between two half-spaces of other two different materials. The scaled function is introduced to the model through the relative reflectivity and from this the piecewise thickness function. The scaled gray-values piecewise function is in the interval [0,1], which avoids divergences in the reflectivity function and reproduce adequately the phase difference in the extrema values, then the thickness profile is obtained. The thickness function approach was tested by obtaining the meniscus thickness of a water droplet. We got an adsorbed layer thickness of 21 ± 2.2 nm. In addition, we demonstrated numerically that our proposal includes or improves other methods previously reported. The process was validated by simulation and compared with previous works. Finally, the application of our data analysis procedure to obtain dynamic meniscus thickness in real time is discussed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The focus of this study is to examine the short‐ and long‐term causal effects of natural disaster shocks on the stock market and business confidence level in the time‐frequency domain by studying the co‐movements between earthquake data and the Istanbul Stock Index closing prices, using the Wavelet Coherence and Phase Difference analyses. The empirical findings reveal that the relationship between earthquake events and financial markets is not stable over time and across different time horizons. The linkage becomes stronger in the long term when the impact of the earthquake event coincides with a financial crisis reflecting a combined effect. This nexus is also strong during the years 2007–2011 reflecting a similar combined effect of both an earthquake event and the global financial crisis. Meanwhile, co‐movement between the earthquake and the financial market index implies a negative effect in the period 2011–2012, indicating short‐run effects of stock market shocks. Differentiating these short‐term and long‐term effects has implications for risk management and policymaking. [ABSTRACT FROM AUTHOR]

Several studies have focused on jet vectoring and mixing enhancement using continuous jets for the secondary flow. In recent years, studies have applied synthetic jets to secondary flows, wherein the driving source can be easily downsized. However, a method to simultaneously control both the deflection angle and the degree of mixing of the generated flow has not yet been established. Thus, this study proposes a novel nozzle that actively controls the direction and turbulence of the primary jet simultaneously by replacing the facing control port of a conventional flip-flop jet nozzle with compact speakers. Specifically, the control factors considered were the phase difference between the opposing synthetic jets generated by the speakers and the dimensionless frequency of the synthetic jets based on the velocity of the primary flow. The flow field was measured via two-dimensional particle image velocimetry analysis and hot-wire anemometer. Consequently, the influence of the phase difference and dimensionless frequency on the deflection angle and turbulence intensity of the generated flow was investigated. The results indicated that the deflection angle of the generated flow could be controlled by adjusting only the phase difference even for the same dimensionless frequency under specific conditions. Furthermore, optimizing the dimensionless frequency by introducing the phase difference facilitated efficient operation with reduced power consumption. In addition, while controlling the deflection angle by the dimensionless frequency and phase difference, the cross-stream distribution of turbulence intensity could be selected at the set deflection angle, subject to limited restrictions. Thus, the results of this study confirm the feasibility of simultaneously controlling the deflection angle and turbulence intensity of the generated flow.

The thermo-acoustic stability of a combustor may be assessed in its design phase via solving an expression for the interior acoustic field with flame characteristics treated as an input. This input must include the flame response to axial upstream disturbances. Practical details of a response evaluation are expressed for the case of a premixed natural gas burner whose flame is stabilized by means of the combination of swirl and bluff-body. An equation for instability analysis in a gas turbine was derived incorporating a practically-measurable and applicable form of flame response. Velocity disturbances were monitored using a hot-film anemometer and chemiluminescence of heat-release fluctuations using a photomultiplier. The photomultiplier gain sensitivity to the angle of incidence of rays was first determined and taken into account. A method based on coincidence of time series was used to evaluate phase difference between two signals. It was found that the geometry of the settling chamber along with the location of the speakers causes the excitability of the acoustic field experience a sharp peak at 300 Hz which relates to the first natural mode of the chamber. The magnitude of the flame describing function assumes values from nearly zero up to 2.7 depending on frequency and excitation level while the phase depends on frequency only. For the case of the excitations that cause noticeable responses, the ratio of the acoustic wavelengths to the flame length is higher than 30, which shows that a global response for the whole flame instead of a field function may be assumed. [ABSTRACT FROM AUTHOR]

Intensity measurements represent a well-established method to determine the sound power of an emitting object. The principal strength of this technique relies upon the possibility of performing the measurements in situ, with no special required conditions concerning the surrounding sound field. Commercially available sound intensity probes rely on two phase-matched microphones properly spaced concerning the desired frequency range. Given the physical and mathematical principles behind the intensity method, phase differences between the signals assume a crucial role. This report aims to study the possibility of designing a cost-effective acoustic phase calibrator to extract the intrinsic phase mismatch of standard class-1 microphones. A phase calibrator has been designed to identify phase mismatches between the microphones and provide the required corrections at specific frequencies. Numerical acoustical Finite Element Method (FEM). models of the calibrator configurations have been implemented. The results of the numerical models have lately led to three calibrator prototypes that have been produced by 3D-printing and tested. They have shown good results when compared to a commercially available and much more expensive acoustic coupler. [ABSTRACT FROM AUTHOR]

In view of the design difficulties of the vector impedance measurement module with a high dynamic range, this study designs a vector impedance measurement module based on the directional coupler using the directional coupler combined with the high-dynamic-range RF (Radio Frequency) logarithmic amplifier. The hardware and software design framework is given, the mathematical principle of the module is deduced, and the experimental verification and testing of the module are completed. The design makes full use of the characteristics of directional coupler, and the test system is small in size, good in scalability, fast in test speed and high in efficiency. The design can also be extended to a monitoring and measuring module, which can be used in communication equipment as an antenna monitoring component or power intensity control component of communication transmitter. After the verification, a number of practical applications have been developed using this design scheme. The high dynamic range of the proposed designed covers the application scenarios from 20~400 W, and obtains good application effect, which proves that the proposed design has good application, expansibility and high practical value. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Control rod drive mechanism (CRDM) in nuclear reactors powered by two motor generator units running in parallel, an excitation fault in one of the generators will cause the terminal current to rise in another generator, which will cause the overcurrent protection to operate before the loss-of-excitation protection, resulting in nuclear reactor shutdown. To solve the problem of mismatch between loss-of-excitation protection and overcurrent protection, this paper applies the equivalent circuit and phase diagram analysis, obtains the conclusion that the generator terminal current phase after an excitation fault is significantly different from the current phase after a phase-to-phase short circuit fault, based on this, a generator overcurrent protection criterion of compound fundamental current phase difference is constructed, which can solve the maloperation of overcurrent protection under possible excitation fault in actual engineering. Simulation results of PSCAD/EMTDC verify the effectiveness of the proposed methods under different operating modes and fault conditions.

In sound signal processing, angle of arrival indicates the direction from which a propagating sound signal arrives at a point where multiple omnidirectional microphones are positioned. Considering a small underwater platform (e.g., underwater unmanned vehicle), this article addresses how to estimate a non-cooperative target’s signal direction utilizing the minimum number of omnidirectional microphones. It is desirable to use the minimum number of microphones, since one can reduce the cost and size of the platform by using small number of omnidirectional microphones. Suppose that each microphone measures a real-valued sound signal whose speed and frequency information are not known in advance. Since two microphones cannot determine a unique AOA solution, this study presents how to estimate the angle of arrival using a general configuration composed of three omnidirectional microphones. The effectiveness of the proposed angle of arrival estimator utilizing only three microphones is demonstrated by comparing it with the state-of-the-art estimation algorithm through computer simulations.

To understand the effect of coupling parameters between two ultrasonic waves on acoustic cavitation, in this work, Keller-Miksis equation was introduced to built a bubble dynamics model that was used to describe the dynamic evolution of bubble and to discuss the effect of dual-frequency coupling parameters, such as frequency difference f (5 ∼ 280 kHz), phase difference φ (0 ∼ 7π/4 rad), and power allocation ratio β (0 ∼ 9), on acoustic cavitation in the presence of two ultrasonic waves irradiation. The enhancement and attenuation effect of cavitation have also been analyzed in detail by comparing the different dual-frequency combinations with single-frequency mode. It was found that all coupling parameters have a significant impact on acoustic cavitation, where the smaller values of f and φ were employed when β = 1, the stronger cavitation intensity was observed. Nevertheless, as the power allocation ratio is increased from 1 to 9 at φ = 0 for different frequency differences, the acoustic cavitation exhibits an attenuation trend. When the total acoustic power is evenly distributed, namely β = 1, the largest maximum expansion ratio (i.e. 12.96) was obtained at φ = 0 and f = 5 kHz, which represents a strongest cavitation effect. In addition, for different frequency combinations, the enhancement effect is found under the mixture of low and low frequency, whereas attenuation effect is generated easily by the combination of high and low frequency. Moreover, the effect become more pronounced as the proportion of high frequency component increases.

In this research article, a concept for a secondary RAdio Direction And Ranging (RADAR) angle of arrival based system with cooperative targets transmitting at 2.4 GHz and using Multiple Signal Classification (MuSiC) to determine the angles of incidence is investigated. In addition to introducing common algorithms and presenting thorough derivations, the system is first examined through simulations. To prove the concept, hardware, firmware, and software are developed. For MuSiC, we propose three novel methods to obtain the correct incident angle from the spectrum, especially in strong multipath environments. These methods work either for a single spectrum or for a combination recorded at multiple times. Together with the estimated angles of incidence, our methods determine measures on the respective likelihoods. Based on this, we additionally propose two algorithms for computing the final position. Our system is characterized in both a simple 20 m × 15 m outdoor and a 17 m × 13 m multipath indoor environment, where we achieve a mean angular error of 3◦ and a mean positioning error of 0.67 m for the former using only four base stations with four antennas each. Our novel approach shows position accuracy improvements of 15% outdoors and 25% indoors compared to classical MuSiC estimation. [ABSTRACT FROM AUTHOR]

A double inserts turning with two inserts mounted on a tool shank is proposed to control regenerative chatter vibration in turning of workpieces with low rigidity. In the presenting turning, the forward and the backward inserts are placed with a position offset in the feed direction; and those inserts are also clamped with a height offset each other in the cutter height direction. A part of the waved surface formed in the preceding cut by the forward insert is concurrently removed by the backward insert placed at a higher position than the rotation center of the workpiece. The regenerative effect, then, is controlled to suppress the chatter vibration by cutting the outer modulation with a time delay. This paper describes the principle of the double inserts turning for control of chatter vibration based on phase difference of the outer and the inner modulations. An analytical model, then, is presented to associate the regenerative effect with the offset parameters of the inserts. The cutting tests were conducted to verify the double inserts turning of a slender workpiece with the offset parameters of the inserts obtained by the analytical simulation. The chatter vibration is controlled effectively by adjusting the offset parameters of the inserts corresponding to the turning parameters. • A novel turning operation is proposed to control regenerative chatter vibration in double inserts cutting by two inserts. • Regenerative effect can be controlled by cutting a part of the outer modulation with phase difference by using two inserts. • An analytical model is presented to determine the offset parameters of the inserts for control of the chatter vibration. • The double inserts cutting may be simply applied to normal turning operations without any additional equipment. [ABSTRACT FROM AUTHOR]

The biodynamic response of 14 subjects to sinusoidal dual-axis vibration in lateral and roll directions is studied. The root mean square of human response is detected by measuring the torque at the seat pan. The effects of phase difference, magnitude, and frequency on the biodynamic responses are investigated. The consistency between human responses to dual-axis and single-axis is studied. With increasing phase difference, human response is found to reach the maximum when the vibrations are anti-phase and then decrease to the minimum when they are in-phase. Besides, the dominance of the lateral excitation is confirmed in the dual-axis vibration. Finally, the principle of equivalence between lateral-roll dual-axis vibration and roll single-axis vibration is established. With the equivalence method, the biodynamic characteristics of the human body to multi-axis vibration are expected to be measured and represented with a much simpler test and dynamic model. Practitioner summary: Proposed equivalence uses one index to evaluate the compound discomfort caused by the roll and lateral vibration. Overestimation of discomfort due by summing the effects of them calculated separately can be avoided. After the equivalence, evaluation of discomfort and modelling of the human body can be carried out only in roll direction. [ABSTRACT FROM AUTHOR]

Ground-penetrating radar (GPR) has been widely applied to the detection and delineation of buried targets in the subsurface. Compared with conventional single-channel GPR, polarimetric GPR has been proven to possess an improved ability to detect and characterize an elongated object in the subsurface. This letter proves that the scattering signals from a cylinder in two orthogonal polarization channels have a phase difference of about 90° when its diameter-to-wavelength ratio is about 0.05–0.33. Consequently, a polarization-difference imaging method, which shifts the VV component by −90° and subtracts it from the HH component, is proposed for the improved detection and imaging of a subsurface elongated object. Its effectiveness is verified by numerical, laboratory, and field tests on buried rebars and pipes. The signal-to-clutter ratios of the reconstructed GPR images can be improved by up to 4.5 dB by considering the phase difference between the dual-polarization components. [ABSTRACT FROM AUTHOR]