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A methodology for the design calculation of a new design of a hydraulic pulse vibrator with a valve pressure pulse generator of a parametric type has been developed, which allows determining its energy, power and geometric parameters. [ABSTRACT FROM AUTHOR]

The P-wave peak distribution in azimuth and takeoff angles, corrected for the distance through empirical attenuation laws, can reveal the radiation pattern amplitude of the source (Tarantino et al., 2019). This piece of information, jointly combined with the available polarities and S-wave peak amplitudes, can provide the full focal mechanism, constraining the solution also when only a few seismic station records are available, that is, in the case of microseismicity. We proposed a new technique, named P-, S-wave amplitude, and polarities (P-SAP), designed to compute the focal mechanism by jointly inverting the P-, S-wave amplitude ratios and P-wave polarities in a Bayesian framework and employing the octree strategy (Fang et al., 1996) to explore the space of possible solutions. The outputs are strike, dip, and rake angles of the most likely triplet (principal and auxiliary planes) with the related uncertainties, as well as other multiple solutions, if present. We tested the methodology to synthetic data, and we applied it to a microseismic sequence that occurred in Irpinia region, southern Italy. A background microseismicity occurs in a volume delimited by the faults activated during the 1980 M 6.9 Irpinia earthquake. This faults system is complex and composed of northwest-southeast-striking normal faults along the Apennines chain and an approximately east-west-oriented strike-slip fault, deep-seated in the Potenza area. A network of three-component accelerometers and velocimeters are currently deployed to monitor the area. The major topic of this work is validating the proposed P-SAP methodology for microseismicity studies. We also inferred the optimum stress tensor of the sequence, confirming that the microseismicity is controlled by the regional stress field and can reveal characteristics useful to highlight behaviors of larger-scale seismicity. [ABSTRACT FROM AUTHOR]

The wave frequency and energy of traditional piezoelectric emission sources used in acoustic logging are limited, which results in an inadequate detection resolution for measuring small-scale geological formations. Additionally, the propagation of these waves in formations is prone to loss and noise interference, restricting detection to only a few tens of meters around the well. This paper investigates an impulse sound source, a new emission source that can effectively enhance the frequency range and wave energy of traditional sources by generating excitation waves through high-voltage discharges in a fluid-penetrated electrode structure. Firstly, a high-voltage circuit experimental system for the impulse sound source was constructed, and the discharge and response characteristics were experimentally analyzed. Then, four types of needle series electrode structure models were developed to investigate and compare the effects of different electrode structures on the impulse sound source, with the needle-ring electrode demonstrating superior performance. Finally, the needle-ring electrode structure was optimized to develop a ball-tipped needle-ring electrode, which is more suitable for acoustic logging. The results show that the electrode structure directly influences the discharge characteristics of the impulse sound source. After comparison and optimization, the final ball-tipped needle-ring electrode exhibited a broader frequency range—from zero to several hundred thousand Hz—while maintaining a high acoustic amplitude. It has the capability to detect geological areas beyond 100 m and is effective for evaluating micro-fractures and small fracture blocks near wells that require high detection accuracy. This is of significant importance in oil, gas, new energy, and other drilling fields. [ABSTRACT FROM AUTHOR]

The temperature measurement during grinding process is difficult due to work–wheel interactions and nearby coolant layers. Surface integrity also gets affected by the grinding burns caused due to high heat generation. Therefore, the theoretical temperature estimation could provide prior detection of grinding burns. This article presents an analytical model to predict the heat flux in pressurized lubricated ultrasonic-assisted surface grinding of Nimonic 80 A using Cubic Boron Nitride (cBN) grinding wheel (vitrified grinding bond, grit 80/100, concentration 100%). In this process, the high frequency of ultrasonic vibration and low amplitude is employed to vibrate the workpiece. In the current modeling approach, the motion analysis of grains has been estimated initially, which provided the effective grinding force. This effective grinding force was then utilized to obtain the analytical model of heat flux. Finally, the model was formulated by considering the effect of heat conducted into the material and heat released due to the lubrication system. The established model comprised the effects of lubricating and machining parameters such as dynamic viscosity of cutting fluid, pressure, diameter and length of cutting fluid pipes, width of cut, frequency, speed of table, amplitude, depth of cut and speed of the wheel. This numerical model revealed affirmative results substantiated by experimentally procured data. This developed model can add to the direction of sustainable grinding approach. [ABSTRACT FROM AUTHOR]

An unconventional and innovative mechanical transmission component, the curved groove ball bearing without retainer (CGBBR), is introduced in this article to facilitate the conversion between rotational and reciprocating motion. The CGBBR boasts several advantages over conventional motion conversion mechanisms, including a streamlined and compact structure, as well as the mitigation of high-order vibrations. This article delves into the design methodology, structural attributes, kinematic principles, and dynamic response properties of the CGBBR. A novel design method named closed curve envelopment theory is proposed to generate the distinctive spatial surface structure of the CGBBR. Moreover, a design scheme is presented that employs the concept of diameter-stroke ratio for CGBBR implementation. A calculation methodology is also introduced for determining the number of rolling elements within the CGBBR, which serves as the foundation for subsequent optimization design. This article deeply analyzes the kinematics principle of CGBBR and provides a new insight of motion conversion in mechanism. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the impact of different surface roughness levels on a staggered arrangement of tubes in a cross-flow configuration, with water as the fluid being used. The focus lies in comparing the data obtained from the rough surface configuration with that of a smooth cylinder reference point. To assist this comparison, a comprehensive two-dimensional computational fluid dynamics (CFD) model is created, which accurately represents the distinctive characteristics of each surface shape. This study also included modifying the Remax within a range of 10 000–16 000 and analyzing the outcomes of using four different tube types, each with different supernatant thicknesses labeled as A = 0 , A = 0. 1 , A = 0. 2 and A = 0. 4 accordingly. Surprisingly, the tube with a 0.4 wave surface had significantly higher average Nusselt numbers (Nu) compared to the other tubes, indicating superior performance. The ideal tube design was found based on three main metrics: The performance evaluation criterion (PEC), the global performance criterion (GPC) and the average Nu. The performance metrics encompassed the PEC, GPC and the Colburn factor (j). The average Nu of the wavy_0.4 tube was higher than that of the SM by 31.66–32.54%, higher than that of the wavy_0.2 tube by 19.76–20.74%, and higher than that of the wavy_0.1 tube by 9.38–16.58%. According to the statistics, a heat exchanger that cools and has a wave with an amplitude of 0 is the most efficient choice for offshore energy systems. The smooth bundle tube (SBT) demonstrated the most significant increase in GPC, with values of 9.3–12.7% and 20.3–28.3% higher than those of wavy tubes with amplitudes of 0.1 and 0.2, respectively. In addition, correlations for the Nu are given, with results verified using empirical data from Balabani et al. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics 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.)

Background: Cluster headache (CH) is a significant health concern due to its major socioeconomic consequences and most patients being refractory to conventional strategies. For treatment resistant CH, occipital nerve stimulation (ONS) is considered an effective treatment option. Whereas most patients do not adjust the amplitude of the ONS system, a subset changes the amplitude on a regular basis using their remote control, and are therefore referred to as 'voltage tuners'. Anxiety and self-control are thought to be central themes to this behavior. Research on this voltage tuning behavior could provide new insights in the use of ONS as acute attack treatment. To date, voltage tuning has not been assessed for CH. Hence this is a unique study aiming to investigate the occurrence and efficacy of voltage tuning in patients with CH and ONS. Methods: For this analysis, patients with CH who received ONS from 2020–2024, at our university medical center, were included. All patients underwent bilateral ONS implantation. Data on attack frequency, intensity and duration were collected retrospectively. Outcomes on the response, frequency, moment during the day, duration, rationale, sensation, average increase in amplitude, and efficacy of voltage tuning were collected with prospective interviews. Results: Thirty-three patients (M = 20) (42 ± 12.7 years) were included in the current analysis. At 1y follow-up, an overall response rate of 70% (23/33) was found for ONS. In total, 48% (18/33) of patients were defined as voltage tuners. Voltage tuning was performed with an average increase in amplitude of 92 (20–360)%, a frequency of 1–20 times/month and duration of 20 minutes-48 hours. Sensations of voltage tuning were described as "tingling" and/or "pinching". The rationale for voltage tuning in patients varied from prevention and ceasing to lowering the intensity and enhance control of CH attack. Conclusions: Outcomes show that voltage tuning may cease and/or terminate CH attacks and therefore raise interests in the use of ONS as acute attack treatment for patients with resistant CH treated with ONS. Future research on the occurrence and potential of voltage tuning will provide valuable insights for achieving optimal efficacy of ONS and quality of life in patients with CH. [ABSTRACT FROM AUTHOR]

We obtain a nonlinear second-order differential equation that describes forced vibrations in a milking machine. Approximate analytical solutions of the obtained differential equations are given. [ABSTRACT FROM AUTHOR]

Understanding the acoustic characteristics of hydrates in various sediments is crucial for hydrate resource detection and safe and efficient exploitation, as hydrate occurrence patterns vary greatly in different sediments. In this work, sediments with different bentonite contents, water saturations, and types were prepared to investigate the characteristics of P-wave velocity (reflecting the magnitude of hydrate saturation in the sediment) and amplitude (reflecting the degree of hydrate-sediment cementation) during hydrate formation and depressurization. During hydrate formation, the P-wave velocity and amplitude have similar trends. As clay content increases, the P-wave velocity increase rates quickened. On the other hand, the increased rate of P-wave velocity slows down with the increase of water saturation in the clay-bearing sediments. Comparing various types of sediment shows that the water absorption and swelling of bentonite reduce the pore space, speeding up the cementation of the hydrate with the sediment and increasing P-wave velocity at a faster rate. Correspondence between P-wave velocity and hydrate saturation is strongly related to sediment type, clay content, and water saturation. The rapidly decreasing amplitude in the early stage of hydrate depressurization indicates that hydrate in clay-bearing sediments is weakly cemented to the sediments, which is prone to stratigraphic instability. The findings of this study offer guidance for hydrate resource assessments in clay-bearing sediments as well as geologic risk estimations during hydrate mining. [ABSTRACT FROM AUTHOR]

The vocal behavior of Neotropical birds has received less attention compared to birds in Northern temperate regions. Many bird species rely on acoustic communication to establish and maintain territories and to interact with conspecifics. For this reason, the growing threat of noise pollution in their habitats is a cause for concern. Birds perform behavioral adjustments when confronted with atypical environmental situations (e.g. urban noises, artificial light, human voice or vegetation loss). The aim of this study was to investigate vocal adjustments of Masked Gnatcatcher (Polioptila dumicola) males in environments located near a route with varying level of traffic noise (measured in decibels) and differing percentage of cover vegetation. Linear mixed models (LMMs) were used to analyze the effects of both environmental parameters in P. dumicola song. Results reveal that P. dumicola increases the amplitude of its songs in response to higher levels of traffic noise. Cover vegetation did not show any effect on song parameters. The model with the highest significance demonstrates a positive linear relationship between amplitude and traffic noise. These findings underscore the importance of studying communication alterations in noisy environments and understanding the ecological consequences of such effects on bird populations. [ABSTRACT FROM AUTHOR]

[Objective] To study the load-bearing capacity of variable span and amplitude steel trestle bridges under multiple loading conditions. [Method] A steel trestle bridge in the construction of the Xiangtang-Putian left line special bridge on the Xiangtang-Putian connection railway line is taken as the research object. A numerical model was established by using the bridge limited element software Midas civil to carefully study the stress state of each component under five different conditions. [Result] The results show that the bailey beam has a large safety margin under different conditions; the safety margin factor of the pile top distribution beam is small under condition 1 and 2, reaching only 1.23 and 1.20, and the safety margin factor of its stiffness is 1.20 under condition 5. It is necessary to avoid excessive temporary loads during construction; the positive stress safety margin factor of the steel tube column under condition 5 is only 1.50, and measures should be taken to ensure safety during construction; the design of the triangular area at the corner meets the structural performance requirements. [Conclusion] The results may provide some reference for the design of similar trestle bridges. [ABSTRACT FROM AUTHOR]

Abstract Background Cluster headache (CH) is a significant health concern due to its major socioeconomic consequences and most patients being refractory to conventional strategies. For treatment resistant CH, occipital nerve stimulation (ONS) is considered an effective treatment option. Whereas most patients do not adjust the amplitude of the ONS system, a subset changes the amplitude on a regular basis using their remote control, and are therefore referred to as ‘voltage tuners’. Anxiety and self-control are thought to be central themes to this behavior. Research on this voltage tuning behavior could provide new insights in the use of ONS as acute attack treatment. To date, voltage tuning has not been assessed for CH. Hence this is a unique study aiming to investigate the occurrence and efficacy of voltage tuning in patients with CH and ONS. Methods For this analysis, patients with CH who received ONS from 2020–2024, at our university medical center, were included. All patients underwent bilateral ONS implantation. Data on attack frequency, intensity and duration were collected retrospectively. Outcomes on the response, frequency, moment during the day, duration, rationale, sensation, average increase in amplitude, and efficacy of voltage tuning were collected with prospective interviews. Results Thirty-three patients (M = 20) (42 ± 12.7 years) were included in the current analysis. At 1y follow-up, an overall response rate of 70% (23/33) was found for ONS. In total, 48% (18/33) of patients were defined as voltage tuners. Voltage tuning was performed with an average increase in amplitude of 92 (20–360)%, a frequency of 1–20 times/month and duration of 20 minutes-48 hours. Sensations of voltage tuning were described as “tingling” and/or “pinching”. The rationale for voltage tuning in patients varied from prevention and ceasing to lowering the intensity and enhance control of CH attack. Conclusions Outcomes show that voltage tuning may cease and/or terminate CH attacks and therefore raise interests in the use of ONS as acute attack treatment for patients with resistant CH treated with ONS. Future research on the occurrence and potential of voltage tuning will provide valuable insights for achieving optimal efficacy of ONS and quality of life in patients with CH.

This paper reviews the latest findings on instability and subcritical transition to turbulence in wall-bounded flows (i.e., pipe Poiseuille flow, plane channel flow, and plane Couette flow). The main focus was on the early stage of transitional flow and the appearance of coherent structures. The scaling of threshold disturbance amplitude for the onset of natural transition was discussed. Generally, the scaling proved to be in the form of Ac = O(Reg) for Newtonian fluids where Re is the Reynolds number, g ≤ -1, and Ac is the critical perturbation amplitude. It was noted that exploration of perturbations like vortices, streaks, and traveling waves together with their amplitudes could clarify the instability and transition process. Hence, this paper focused on physical behavior and realizations of the transitional flow. Finally, a summary of consequential implications and some open issues for future works were presented and discussed.

Background: To study Visual Evoked Potential in patients with Optic Nerve diseases. Study design and settings: Cross – Sectional study. Material and Methods: 72 patients were included in our study, aged 12 years and above, diagnosed as optic nerve diseases like optic neuritis, Nonarteritc ischemic optic neuropathy (NAION), hereditary, nutritional and compressive optic neuropathy etc. Flash and Pattern VEPs were used. VEP amplitude and latency were noted. Results: Out of total 144 eyes, 107 eyes were affected. Ethambutol induced Toxic optic neuropathy was the most common etiology, followed by secondary optic neuropathy, idiopathic, traumatic optic neuropathy, optic neuritis, NAION, compressive and post CRAO (Central Retinal Artery Occlusion) optic neuropathy. Mean latency of all affected eyes was 132±22.5 msec. mean amplitude of the all affected eyes was 6.36±2.1 microvolt. Latency was moderately delayed (110-140 msec) in 45.8%, while severely delayed (>140 msec) in 40.3% of total eyes. Amplitude was reduced in 36.5% of total eyes. Prolonged latency with normal amplitude was found in most of the eyes with optic neuritis while latency was also prolonged in fellow eyes of optic neuritis. In case of NAION prolonged latency and reduced amplitude was found in all eyes. Conclusion: Flash or pattern VEP can be used as an important tool for diagnosis of optic neuropathies or revealing of recurrence of disease and for follow up. VEP can also be used to detect subclinical damage in the fellow eyes of optic neuritis and also useful in differentiating the optic neuritis from ischemic optic neuropathy.

Accurately representing the precipitation diurnal cycle has long been a challenge for global climate models (GCMs). Here we evaluate the precipitation diurnal cycle in the DYAMOND global convection‐permitting models (CPMs) and CMIP6 HighResMIP models. Comparison of the high‐ (25–50 km) and low‐resolution (100–250 km) models with parameterized convection in HighResMIP shows that simply increasing model resolution does not noticeably improve the precipitation diurnal cycle. In contrast, CPMs can better capture the observed amplitude and timing of precipitation diurnal cycle. However, the simulated spatial variation of timing in CPMs is smaller than observed, leading to an exaggeration of the spatially averaged diurnal amplitude. The better‐simulated precipitation diurnal cycle in the CPMs is tied to mesoscale convective systems (MCSs), which contribute about half of the total precipitation. The observed life cycle of MCSs, including initiation and mature stages, is well captured in the CPMs, leading to a more realistic precipitation diurnal cycle. Plain Language Summary: As a basic mode of climate variability, the diurnal cycle is a key metric that has been used to benchmark climate models. The current state‐of‐the‐art GCMs struggle to accurately represent the precipitation diurnal cycle, frequently peaking too early compared to the observations. Due to the coarse resolution and the use of convection parameterization, GCMs are also unable to simulate organized convective storms, which often exhibit a distinct diurnal cycle. With the emergence of global storm‐resolving models at kilometer‐scale resolution, this study evaluates the diurnal cycle of precipitation simulated by global storm‐resolving models and high‐resolution GCMs. We find that at resolutions between ∼25 and 250 km, increasing resolution has limited effects on the precipitation diurnal cycle but global CPMs can reproduce the observed precipitation diurnal cycle much better as they can better represent organized convective storms. Key Points: Precipitation diurnal cycle is systematically evaluated in DYAMOND simulations from global convection‐permitting models (CPMs) and CMIP6 modelsBoth the amplitude and phase of the precipitation diurnal cycle are better simulated by CPMs than CMIP6 high‐resolution modelsThe global CPMs excel in reproducing the precipitation diurnal cycle owing to better simulated mesoscale convective systems [ABSTRACT FROM AUTHOR]

To realize fast and accurate measurement of grain moisture with low cost, the miniaturized channel state information (CSI) acquisition equipment was used for grain moisture detection. Two feature selection algorithms of random forest and principal component analysis were adopted to extract the feature subcarriers of the CSI amplitude index, and the ten kinds of grain moisture were classified based on the selected feature subcarriers. Considering that the application in the mobility scene was limited by power consumption and arithmetic power, the breadth learning system with simple structure, fast operation speed and low arithmetic power requirement was selected for processing CSI data and was compared with the traditional convolutional neural network (CNN) in terms of accuracy and training time. The enhancement nodes of the broad learning system (BLS) were dynamically increased. The experimental results show that the principal component analysis (PCA) algorithm maximally eliminates the redundant information in the CSI data. Compared with the CNN, the BLS can achieve faster speed and better accuracy. Therefore, the PCA-BLS combination achieves the best classification results. Increasing the number of enhancement nodes can increase the training time, but the recognition accuracy is improved to some extent. [ABSTRACT FROM AUTHOR]

A new vibrating plate viscometer has been developed which is used and makes it possible to instantly and continuously measure the viscosity of a high-temperature material. This viscometer is designed for industrial use and enables one to measure the viscosity automatically to a high accuracy. This method of measuring the viscosity is currently used in various fields, such as the study of newly produced oil products, the selection of the optimal flow characteristics for various transfer conditions, and the development and improvement of preparing fuels. [ABSTRACT FROM AUTHOR]

This study investigates the temporal and spatial complexities of the mean diurnal cycle (DC) of precipitation over the Maritime Continent during the wet season using the Integrated Multi‐satellite Retrievals for GPM (IMERG) data product and highlights systematic inaccuracies of amplitude and phase representation using the first diurnal harmonic (FDH). The first‐order nature of the DC of precipitation is already well documented, typically featuring heavy precipitation over near‐coastal land areas in the late afternoon and evening followed by maximum precipitation overnight over the surrounding seas, with offshore propagation evident in places. The DC is often described concisely in terms of an amplitude and phase based on the FDH parameters, however the omission of higher‐order components of variability results in the FDH parameters being poor indicators of the magnitude and peak time of diurnal variability in many locations. This study improves the accuracy of the amplitude and phase parameters by characterising the DC using two novel waveforms—a skew‐permitting waveform and a spike‐permitting waveform—which are constructed to characterise single‐peak cycles with rapid transitions more accurately. Key characterisation improvements include correction of a phase lag (averaging approximately 1 h) over near‐coastal land areas and capture of the short‐lasting but extreme peak in precipitation rate over Java which increases the amplitude by the order of 20%. The new skew parameter shows that locations close to coastlines experience rapid intensification and gradual weakening of diurnal precipitation, while there is a tendency toward gradual intensification and rapid weakening far inland and offshore. The new spike parameter shows that near‐coastal land experiences a brief and precisely timed peak in precipitation, whereas diurnal activity over inland locations is longer‐lasting and less precisely timed, and waters surrounding Java experience a precisely timed suppression of precipitation. Other potential applications of the novel waveforms used in this study are discussed. [ABSTRACT FROM AUTHOR]

Relying on scrap rates alone to assess process control in the foundry can be deceiving. Depending on the inspection method used, it is possible to sort grossly non-conforming parts, while still allowing a wide window of acceptance, masking a process that is out of control. Modern methods of acoustic resonance testing (ART) allow for detailed data logging of both part weight and resonant frequency peak data. Monitoring these two factors at the lot level can give foundry managers insight into how consistent their process is both within a single date code and across multiple date codes. The information collected during quality testing can and should be combined with statistical information gathered at the front of the foundry (design, tooling, molding, inoculation, pouring, cooling, and shakeout) and used to adjust the process to achieve smaller data spreads and more consistent and repeatable process control. Once a process is deemed to be under control, consideration should be given to monitoring the defined specification limits and subsequent control limits using statistical trend analysis as a means for ensuring a process is not approaching a condition in which the opportunity for quality issues can arise. [ABSTRACT FROM AUTHOR]

The objective of the present study was to investigate the impact of mechanical vibration on the microstructure and mechanical properties of AlSi5Cu3 alloy. To achieve this, a custom vibrating setup was developed in-house to apply mechanical vibrations to the aluminum alloy. The vibrations were applied at a fixed frequency of 30 Hz, with varying vibrational amplitudes of 10, 15, and 20 μm, and different vibration times of 1, 1:30, and 2 min. The analysis of the conventional cast sample revealed a coarse dendritic structure with an average grain count of 2316 grains/mm2. This sample exhibited the lowest hardness and ultimate tensile strength measuring 38.25 HRB and 172 MPa, respectively. However, as the vibrational amplitude and time increased, significant improvements were observed in grain refinement and mechanical properties. The maximum grain refinement was achieved at a vibrational amplitude of 20 μm and a vibration time of 2 min. Under these conditions, the number of grains per unit area increased to 3785 grains/mm2, representing a 63% increment. Additionally, the coarse dendritic structure transformed into an equiaxed grain structure. The maximum percentage increment of hardness, ultimate tensile strength, and yield strength is 19, 16, and 16% for 20 μm of vibrational amplitude and vibration time of 2 min as compared to the conventional cast sample. The hardness, ultimate tensile strength and yield strength are 45.39 HRB, 199 MPa and 141 MPa, respectively. These findings highlight the positive influence of mechanical vibration on the microstructure and mechanical properties of AlSi5Cu3 alloy. [ABSTRACT FROM AUTHOR]

Land monsoon rainfall has a distinct annual cycle. Under global warming, whether the phase and amplitude of this annual cycle would be changed is still unclear. Here, a global investigation is conducted using 34 CMIP6 and 34 CMIP5 models under a high emission scenario. Seasonal delays would occur in the Southern Hemisphere (SH) American (3.43 days), Northern Hemisphere (NH) African (5.98 days) and SH African (3.76 days) monsoon regions, while no robust signal is found in other monsoon regions. Except NH American monsoon, amplitude is enhanced in all the monsoon regions. Compared to amplitude, the phase changes dominate the future changes of precipitation in the SH American, NH African and SH African monsoon regions. In these phase‐dominated regions, atmospheric energetic framework is proved to be reliable at regional scale and the enhanced effective atmospheric heat capacity is found to be the dominant factor. Plain Language Summary: Monsoon rainfall sustains nearly two‐thirds of the world's population. The arrival timing and the difference between maximum and minimum of monsoon are the main features of concern. We revealed that rainfall would be delayed over the Amazon, Sahel and South Africa and enhanced in most monsoons except North American monsoon under global warming. In the Amazon, Sahel and South Africa, future changes of the arrival timing can be more remarkable compared to the changes of range. These regional changes can be resulted from physical constraints related to atmospheric energy under global warming, which was previously proposed at larger scale and has been proved to be reliable here at regional monsoons. Key Points: Precipitation would be robustly seasonally delayed over the South American, North African and South African monsoons under global warmingThe phase delays would dominate precipitation annual cycle changes in the above three regions, while amplitude changes dominate the othersThe enhanced effective atmospheric heat capacity under warming is key to the seasonal delay of precipitation at the phase‐dominated regions [ABSTRACT FROM AUTHOR]

• Latencies of cR1 have low intra-class variability. • Delayed cR1 onset and high cR1 activation thresholds are indicative of ELAR dysfunction. • Unsustained cR1, desynchronized cR1, and absence of cR2 signal an abnormal ELAR behavior. The laryngeal adductor reflex (LAR) is vital for airway protection and can be electrophysiologically obtained under intravenous general anesthesia (IGA). This makes the electrophysiologic LAR (eLAR) an important tool for monitoring of the vagus nerves and relevant brainstem circuitry during high-risk surgeries. We investigated the intra-class variability of normal and expected abnormal eLAR. Repeated measures of contralateral R1 (cR1) were performed under IGA in 58 patients. Data on presence/absence of cR2 and potential confounders were also collected. Review of neuroimaging, pathology and clinical exam, allowed classification into normal and expected abnormal eLAR groups. Using univariate and multivariate analysis we studied the variability of cR1 parameters and their differences between the two groups. In both groups, cR1 latencies had coefficients of variation of <2%. In the abnormal group, cR1 had longer latencies, required higher activation currents and was more frequently desynchronized and unsustained; cR2 was more frequently absent. cR1 latencies show high analytical precision for measurements. Delayed onset, difficult to elicit, desynchronized and unsustained cR1, and absence of cR2 signal an abnormal eLAR. Understanding the variability and behavior of normal and abnormal eLAR under IGA can aid in the interpretation of its changes during monitoring. [ABSTRACT FROM AUTHOR]

One of the old methods of butter production, which is still used in parts of Africa and the West of Asia, is the process of churning in the skin of a goat or deer that is half filled with milk or yogurt and air, which is beaten reciprocating. This type of butter production in the current research is mechanized and is called machine-type reciprocating butter churner (MRBC). This device is composed of chassis, churner, churn carrier, connector or crank, rotating wheel, driving system or power transmission and balance weights. In order to evaluate MRBC, the effect of churning amplitude (40, 60 and 80 cm), churning frequency (50, 61 and 72 cpm) and the churner volume (13.5 and 21.3 liters) on the butter yield was investigated. The results showed that the amplitude, frequency and churner volume had a significant effect on the butter yield at the level of 1%. Regardless of the churner volume, the minimum and maximum butter yield was obtained in the lowest and highest amplitude and frequency, respectively. The present study gives a general overview of the butter yield affected by machine mechanical parameters. [ABSTRACT FROM AUTHOR]

Structural health monitoring is implemented to monitor the structural integrity of the structure. The guided wave technique is utilized to investigate the health status of the aluminum plate. The wave is actuated at 6 kHz using a PZT actuator and recorded using the optical fiber sensor. The wave is recorded on the intact plate at 2‐ and 4‐mm thickness. Three different defect depths are introduced on the 4 mm plate's thickness, and three different defect widths are introduced on the 2 mm plate's thickness. The recorded waves measured on the 1/3, 2/3, and 3/3 of the defect depths show a wave amplitude decrement of 72%, 84%, and 88%, respectively, compared to the wave amplitude of the intact plate. For the defect widths of 1, 1.5, and 2 cm, the decrement of the wave amplitude is 83%, 87%, and 94%, respectively. The severity of the structure can be monitored by the decrement of the wave amplitude. The finding shows that the guided wave approach is able to be utilized as one of the promising techniques to monitor the structural integrity of the metallic structure. [ABSTRACT FROM AUTHOR]

The single macroscopic flow on the boundary of a closed curve equals the sum of the countless microscopic flows in the enclosed area. According to the dictates of the Green's theorem, the counterclockwise movements on the border of a two-dimensional shape must equal all the counterclockwise movements taking place inside the shape. This mathematical approach might be useful to analyse neuroscientific data sets for its potential capability to describe the whole cortical activity in terms of electric flows occurring in peripheral brain areas. Given a map of raw EEG data to coloured ovals in which different colours stand for different amplitudes, the theorem suggests that the sum of the electric amplitudes measured inside every oval equals the amplitudes measured just on the oval's edge. This means that the collection of the vector fields detected from the scalp can be described by a novel, single parameter summarizing the counterclockwise electric flow detected in the outer electrodes. To evaluate the predictive power of this parameter, in a pilot study we investigated EEG traces from ten young females performing Raven's intelligence tests of various complexity, from easy tasks (n = 5) to increasingly complex tasks (n = 5). Despite the seemingly unpredictable behavior of EEG electric amplitudes, the novel parameter proved to be a valuable tool to to discriminate between the two groups and detect hidden, statistically significant differences. We conclude that the application of this promising parameter could be expanded to assess also data sets extracted from neurotechniques other than EEG. [ABSTRACT FROM AUTHOR]

Powder deposition is a very important aspect of PBF-based additive manufacturing processes. Discrete Element Method (DEM) is commonly utilized by researchers to examine the physically complex aspects of powder-spreading methods. This work focuses on vibration-assisted doctor blade powder recoating. The aim of this work is to use experiment-verified DEM simulations in combination with Taguchi Design of Experiments (DoE) to identify optimum spreading parameters based on robust layer quality criteria. The verification of the used powder model is performed via angle of repose and angle of avalanche simulation–experiment cross-checking. Then, four criteria, namely layer thickness deviation, surface coverage ratio, surface root-mean-square roughness and true packing density, are defined. It has been proven that the doctor blade's translational speed plays the most important role in defining the quality of the deposited layer. The true packing density was found to be unaffected by the spreading parameters. The vertical vibration of the doctor blade recoater was found to have a beneficial effect on the quality of the deposited layer. Ultimately, a weighted mean quality criteria analysis is mapped out. Skewness and kurtosis were proven to function as effective indicators of layer quality, showing a linear relation to the weighted means of the defined quality criteria. The specific weights that optimize this linearity were identified. [ABSTRACT FROM AUTHOR]

Soil layers affect the vertical movement of moisture and salt, eventually resulting in land cover and land use pattern changes. This study explored the ability of ground penetrating radar (GPR) to detect soil layers in the modern Yellow River Delta of China and assessed its accuracy. It was found that soil moisture and salt had a strong dampening effect on the electromagnetic wave signal which resulted in blurred GPR images of the soil profile below 1 m. The cultivated soil layers of different crop types, such as rice, wheat, corn and cotton, were accurately identified in GPR images. To estimate an individual soil layer thickness, the propagation velocity of the electromagnetic wave was calculated using soil mass moisture content, and the propagation time was confirmed by comparing the GPR image with the amplitude–time plot of the soil profile. The estimated thickness was 1.02 times the thickness determined in the field and the average estimation error was 0.04 m, which was 24.09% of the soil layer thickness determined in the field. The second derivative value of envelope amplitude energy with time (SDEA) was used to describe the amplitude change in the soil layers. The SDEA has negative logarithmic and power function relationships with soil mass moisture content and electrical conductivity, respectively. The present results provide a reference database for future quantitative soil investigation in the sedimentary plain area using GPR. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office 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.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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 relativistic quantum equation is proposed for the complex wave function, which has the meaning of a probability amplitude. The Lagrangian formulation of the proposed theory is developed. The problem of spreading of a wave packet in an unlimited space is solved. The relativistic correction to the energy levels of a harmonic oscillator is found, leading to a violation of their equidistance. [ABSTRACT FROM AUTHOR]

Study Design. A retrospective case-control study. Objective. To differentiate neurodegenerative diseases from compressive cervical myelopathy (CCM) using motor-evoked potentials (MEPs). Summary of Background Data. When considering surgery for CCM, it may be necessary to differentiate the condition from a neurodegenerative disease. Materials and Methods. A total of 30 healthy volunteers, 52 typical CCM patients with single-level compression of the spinal cord at C4-5 or C5-6, 7 patients with amyotrophic lateral sclerosis (ALS), and 12 patients with demyelinating disease of the central nervous system, including 11 patients with multiple sclerosis and 1 patient with neuromyelitis optica spectrum disorder, formed our study population. MEPs were recorded from the bilateral abductor digiti minimi (ADM) and abductor hallucis (AH) muscles using transcranial magnetic stimulation and electrical stimulation of the ulnar and tibial nerves. Central motor conduction time, peripheral conduction time, amplitude of MEPs, and frequency of F waves were evaluated. Receiver operating characteristic curve analysis was used to determine the cutoff value for distinguishing between CCM and ALS. Results. Significant differences were observed in the amplitude of MEPs and frequency of F waves evoked by peripheral nerve stimulation between patients with CCM and ALS. The MEP amplitude of AH was more accurate in differentiating between the two diseases compared with ADM (cutoff value, 11.2 mV, sensitivity, 87.5%; specificity, 85.7%). All 7 patients with ALS showed reduced frequency of F waves from ADM or AH, but none of the healthy volunteers or patients with other diseases demonstrated this finding. Moreover, there were no significant differences between CCM and demyelinating disease of the central nervous system in any of the assessments. Conclusion. The amplitude of MEPs and frequency of F waves evoked by peripheral nerve stimulation could be helpful in differentiating ALS from CCM. [ABSTRACT FROM AUTHOR]

Trunk shakers perform a forced vibration that should be set according to tree species and architecture to efficiently detach fruits. However, manufacturing companies produce designs that are poorly customisable according to different trees. This work presents a prototype that is configurable in amplitude and frequency of vibration, which has been developed to generate the different vibration patterns required by various fruit trees. To study the feasibility of the developed technology, we built a test bench with a post, to which we fixed olive, almond and orange tree branches, and tested different configurations of the machine (frequencies from 12.25 to 20.75 Hz and eccentricities from 58 to 86 mm). Acceleration values were recorded at different points: the trunk shaker, the post in the grip, the top of the post, and in each branch. We recorded a large loss of acceleration transmissibility between the shaker and the post (20%–60%) due to existing frictions that dissipate energy through heat loss. There is a non-linear increase between vibration frequency and the resultant acceleration value recorded, as well as with increasing eccentricity. The shaker was able to provide a different vibration pattern in each configuration, affecting the transmission of vibration in each of the branches studied, for which mean acceleration transmissibility ranged between 82% (almond), 104% (olive) and 136% (orange). [ABSTRACT FROM AUTHOR]

Objectives: Global navigation satellite system (GNSS) interferometric reflectometry (GNSS-IR) is a new passive remote sensing technique for determining surface environment parameters, which places an important part in the inversion of earth's surface properties, such as soil moisture monitoring, snow parameter retrieval, and vegetation remote sensing, etc. GNSS-IR offers several benefits over the traditional soil moisture inversion approach, including all-weather capability, high temporal precision, and cheap cost. Methods: Considering the fact that the existing soil moisture inversion algorithms only utilize one single feature of GNSS reflected signal and from the perspective of increasing data availability, this paper proposes a GNSS-IR soil moisture inversion approach that integrates multi-type feature data by utilizing phase, amplitude, and frequency extracted GNSS signals reflected by soil. The main work is to effectively filter all available features extracted from the original GNSS signal-to-noise ratio observations. The feasibility and effect of the suggested method are compared and evaluated using three machine learning models, including least squares support vector machine (LSSVM), random forest (RF), and back propagation neural network (BPNN). Results: Comparing the inversion effects of above three models, BPNN model has the best inversion effect, followed by RF model, and LSSVM model is the worst. The results show that the correlation coefficients between the reference value and soil moisture inversed by the multi-feature fusion method LSSVM, RF, and BPNN models are 0.830, 0.953, and 0.980, respectively, and the corresponding root mean square errors are 0.045, 0.035 and 0.032 cm³ /cm³ Conclusions: Compared with the single feature inversion method, both the accuracy and correlation coefficient of soil moisture inversion increase significantly. The results demonstrated that the proposed method has higher inversion accuracy and reliability than the single feature inversion method. [ABSTRACT FROM AUTHOR]

Lotka-Volterra model continues to be of interest to numerous researchers, both in terms of its mathematical development and applications. This paper discusses an analytical solution of the Lotka-Volterra model near its equilibrium point. This solution, which is the main result of this paper, has not been previously explored by other researchers. The proposed solution is in the form of a series expansion with respect to parameter (1), representing a perturbed solution around the equilibrium point. The analytical solution is evaluated by comparing to both the corresponding exact orbit, which is directly derived from the model, and the corresponding numerical solution. Comparisons with the exact orbit reveal that the orbit formed by the analytical solution closely approximates the exact one. The orbits formed by the analytical solution are closer to the exact ones as approaches zero. Similarly, the analytical solution is also closer to the numerical solution as approaches zero. Additionally, as the solutions exhibit wave-like behavior, further observations are made regarding the 'amplitude' and 'wavelength' of the analytical solution. The wavelength and amplitude of the analytical solutions are closer to the ones of the numerical solutions as tends to zero. The amplitude and wavelength are crucial for optimizing harvesting strategies when applying the Lotka-Volterra model in integrated farming systems. [ABSTRACT FROM AUTHOR]

Background: Current liver magnetic resonance elastography (MRE) scans often require adjustments to driver amplitude to produce acceptable images. This could lead to time wastage and the potential loss of an opportunity to capture a high-quality image. Purpose: To construct a linear regression model of individualized driver amplitude to improve liver MRE image quality. Material and Methods: Data from 95 liver MRE scans of 61 participants, including abdominal missing volume ratio (AMVR), breath-holding status, the distance from the passive driver on the skin surface to the liver edge (Dd−l), body mass index (BMI), and lateral deflection of the passive driver with respect to the human sagittal plane (Angle α), were continuously collected. The Spearman correlation analysis and lasso regression were conducted to screen the independent variables. Multiple linear regression equations were developed to determine the optimal amplitude prediction model. Results: The optimal formula for linear regression models: driver amplitude (%) = −16.80 + 78.59 × AMVR − 11.12 × breath-holding (end of expiration = 1, end of inspiration = 0) + 3.16 × Dd−l + 1.94 × BMI + 0.34 × angle α, with the model passing the F test (F = 22.455, P <0.001) and R2 value of 0.558. Conclusion: The individualized amplitude prediction model based on AMVR, breath-holding status, Dd−l, BMI, and angle α is a valuable tool in liver MRE examination. [ABSTRACT FROM AUTHOR]

The study of a receptor-ligand system generally relies on the analysis of its doseresponse (or concentration-effect) curve, which quantifies the relation between ligand concentration and the biological effect (or cellular response) induced when binding its specific cell surface receptor. Mathematical models of receptor-ligand systems have been developed to compute a dose-response curve under the assumption that the biological effect is proportional to the number of ligand-bound receptors. Given a dose-response curve, two quantities (or metrics) have been defined to characterize the properties of the ligand-receptor system under consideration: amplitude and potency (or halfmaximal effective concentration, and denoted by EC50). Both the amplitude and the EC50 are key quantities commonly used in pharmaco-dynamic modeling, yet a comprehensive mathematical investigation of the behavior of these two metrics is still outstanding; for a large (and important) family of receptors, called cytokine receptors, we still do not know how amplitude and EC50 depend on receptor copy numbers. Here we make use of algebraic approaches (Gr\"obner basis) to study these metrics for a large class of receptor-ligand models, with a focus on cytokine receptors. In particular, we introduce a method, making use of two motivating examples based on the interleukin-7 (IL-7) receptor, to compute analytic expressions for the amplitude and the EC50. We then extend the method to a wider class of receptor-ligand systems, sequential receptor-ligand systems with extrinsic kinase, and provide some examples. The algebraic methods developed in this paper not only reduce computational costs and numerical errors, but allow us to explicitly identify key molecular parameters and rates which determine the behavior of the dose-response curve. Thus, the proposed methods provide a novel and useful approach to perform model validation, assay design and parameter exploration of receptor-ligand systems. [ABSTRACT FROM AUTHOR]

As a result of the uneven growth of rice, unbalanced vibration of threshing drum caused by stalk entanglement in combine harvester is more and more severe. In order to reveal the influence of unbalanced excitation on the roller axis locus during rice threshing, the stability of threshing drum was studied. The dynamic signal test and analysis system are used to test the axial trajectory of threshing drum. At the same time, the influence of the unbalanced excitation caused by the axis winding on the axis trajectory is analyzed by the experimental results. Axis locus rules under no-load and threshing conditions are obtained. In order to simulate the axial and radial distribution of unbalanced excitation along the threshing drum, the counterweight was distributed on the threshing drum instead of the entangled stalk. Then, the definite effect of unbalanced excitation on the rotating stability of threshing drum is analyzed. Results show that the amplitude of stem winding along the grain drum is larger in the vertical direction and smaller in the horizontal direction when compared with the unloaded state under 200 g weight. It was found that the amplitude in both horizontal and vertical directions decreased after 400 g and 600 g counterweights were added, respectively, to simulate the radial distribution of stalk winding along the grain barrel. Finally, it can be seen that with the increase in the weight of the counterweight, the characteristics of the trajectory misalignment of the threshing cylinder axis become more and more obvious. This study can provide reference for reducing the unbalanced excitation signal of threshing drum and improving driving comfort. [ABSTRACT FROM AUTHOR]

Production of California table olives has declined significantly in recent years due to hand harvesting costs, often over 60% of gross return. Mechanical harvesting could sharply decrease harvest costs, increasing economic viability. Mechanical harvester efficiency is a combination of the percentage of the total fruit on a tree removed by a harvester, and the time required to do so. A comparison between an experimental canopy contact shaker and a commercial trunk shaker demonstrated low harvest efficiencies and no significant differences in harvester efficiency between the two, averaging no more than 8%. However, simultaneously combining both shaking methods increased fruit removal to an economically feasible 75% and produced better fruit quality. Combining both shaking methods increased the price per ton by 63% versus trunk shaking and 35% versus canopy shaking. These results suggest a mechanical olive harvester that simultaneously combines trunk and canopy shaking is more efficient than either shaking method alone, and, has potential for economically feasible mechanical table olive harvesting.

The prominent novelty of current review is to exhibit the fluctuating and oscillatory convective heat transfer properties along various geometries with magnetic force, variable density, Prandtl number, buoyancy force and magnetic Prandtl number effects. The significance of present work is to illustrate a comprehensive review on transient convective heat transfer. Transient convective heat transfer plays an essential role in various technological and environmental applications, including climate control, structure safety, engines, thermal control, computer heating and cooling, and energy safety. The literature primarily focuses on steady temperature and velocity domains, with few studies exploring time-varying fluid flow in forced, natural, or mixed convective mechanisms with different methods. In current review, justification of results was performed by using oscillating stokes conditions directly in partial differential models. The similarity variables and stream functions are used in literature but in current review, the primitive variable transformation is used with implicit form of finite difference method and Gaussian elimination technique through FORTRAN and Tecplot-360 programming tools. The governing model is reduced into steady, real and imaginary form to explore steady and oscillating convective heat transmission. Transient flows have gained significance due to their ability to achieve large oscillating convective heat transfer rates. Compared with steady movement, oscillating flows exhibit higher velocity variations along the heated surface. Periodic flow produces an improved transient surface heat transmission rate than steady flow. Predicting and controlling transients in thermal exchangers requires a concept of transient forced convection heat transport. Transient convective thermal transmission solutions are important for ensuring the effectiveness and reliability of electrical components, nuclear and thermal power stations, heat-generating engines, steam turbines, condensation systems, catalytic converters, heat shielding for spacecraft, electrical devices, internal combustion engines, air conditioning and refrigerator components, cooling networks for batteries, generators, and transformers. It is found that the frequency of convective heat transport enhances through periodic and oscillating stokes variables. It was depicted that the higher amplitude in convective heat transfer was displayed for each choice of magnetic force parameter around two angles π/4 and π of circular magnetized surface. It was depicted that the maximum transient convective heat transmission was reported along vertical angle π/2 with buoyancy force, Prandtl and magnetic Prandtl values.

Abstract The crack initiation stress threshold is widely used in excavation industries as rock spalling strength when designing deep underground structures to avoid unwanted brittle failures. While various strain-based methods have been developed for the estimation of this critical design parameter, such methods are destructive and often requires subjective interpretations of the stress–strain curves, particularly in rocks with pre-existing microcracks or high porosity. This study explore the applicability of non-destructive ultrasonic through-transmission methods for determining rock damage levels by assessing the changes in transmitted signal characteristics during loading. The change in velocity, amplitude, dominant frequency, and root-mean-square voltage are investigated with four different rock types including marble, sandstone, granite, and basalt under various stress levels. Results suggest the rate of signal variations can be reliably used to estimate crack closure and crack initiation stress levels across the tested rocks before failure. Comparison of the results between the conventional techniques and the new proposed methods based on ultrasonic monitoring are further discussed.

With rapid urbanization and the structural transformation of economic development, cultivated land abandonment is becoming more serious, posing great threats and challenges to the security of food production. The rapid and accurate monitoring of cultivated land abandonment is of great value for ensuring regional and national food security. In view of the urgent need for abandoned land monitoring, we proposed a method to identify abandoned land based on the temporal features of optical time series data. First, the NDVI time series of cultivated lands was constructed using multitemporal Sentinel-2 data. The constructed NDVI time series was preprocessed to filter out outliers among the observations. Subsequently, the amplitude feature of the NDVI time series was extracted for cultivated land. We acquired the amplitudes of the abandoned and non-abandoned land samples and generated statistics for the range of amplitudes. We then extracted the optimal threshold of NDVI amplitude for separating abandoned land from non-abandoned land using two steps: initialization and optimization of the threshold. In the initialization step, the maximum NDVI amplitude among the abandoned land samples was set as the initial threshold. In the optimization step, the threshold was decreased in step of 0.01, and the F1-score was calculated iteratively to determine the optimal threshold. With a decrease in the threshold when the F1-score reached its highest value, the corresponding threshold was set as the optimal threshold. Accordingly, the rule for abandoned land recognition was constructed; namely, when the NDVI amplitude was lower than the optimal threshold, cultivated land was classified as abandoned land. Finally, based on the mapping results, landscape pattern indices were calculated to analyze the landscape pattern characteristics of abandoned lands. The proposed method was validated in Potou District, Zhanjiang City, Guangdong Province, China. The main results of the study were as follows: 1) Comparing the NDVI time series curves of abandoned and non-abandoned lands, we found that the NDVI time series curves of abandoned land changed gently, whereas the NDVI time series of non-abandoned land changed with great fluctuation due to the phenological process of crop growth. 2) By iteratively searching for the optimal NDVI amplitude, the optimal segmentation threshold of NDVI amplitude was 0.42 for distinguishing abandoned lands from non-abandoned lands in Potou. We used 100 abandoned and non-abandoned land samples to validate their accuracy. By using this optimal threshold, the overall recognition accuracy of abandoned land reached 91.83%, and the overall extraction accuracy of non-abandoned land reached 90.20%. 3) The calculation results of the landscape pattern index of abandoned lands revealed that these are generally small and have irregular shapes. Abandoned lands were scattered throughout Potou. This study demonstrates that the proposed method can effectively identify abandoned land using the amplitude of NDVI time series. This method can produce highly reliable abandoned land mapping and shows good potential for large-scale agricultural applications.

In microprocessor automation and control systems, the amplitude (effective) values of the fundamental harmonic of the input signals are widely used as information parameters of the controlled quantities. They are most often determined by samples of one or a pair of orthogonal components of the signal, for the formation of which digital Fourier filters and their modifications are mainly used. At the rated frequency in the power system, these filters ensure reliable reception of the signal amplitude without additional error. If the frequency deviates from the rated one, the number of samples per signal period is not an integer and the discretization becomes asynchronous. As a result, a corresponding error appears in the amplitude of the signal, and its change becomes oscillating. With minor frequency fluctuations in the normal mode, the amplitude error is insignificant. However, in abnormal situations, the frequency can have significant variations. At the same time, in critical situations, failure of automation and control systems, as well as incorrect operation of their functional algorithms, cannot be excluded. Known methods for determining the amplitude of a signal with frequency fluctuations provide a solution to the existing problem, but they are characterized by a slow response. The proposed high-response method for determining the amplitude during frequency fluctuations is focused on using as initial information samples of instantaneous values of the cosine orthogonal component of the signal, which are formed using an appropriate digital Fourier filter. Based on these samples, the dynamic cosine and sine of the angle of one sample are calculated, the use of which in calculating the amplitude ensures its independence from frequency. Processing of the received amplitude with an amplifying element with a nonlinear coefficient makes it possible to achieve acceptable performance. The effectiveness of the proposed solution was evaluated by a computational experiment using a digital model implemented in the MATLAB-Simulink dynamic modeling environment. In this case, both sinusoidal input signals and complex ones, close to the real secondary signals of measuring transformers, were used as test actions. As a result of the research, it was found that the proposed method for determining the amplitude during frequency fluctuations has a performance at the level of a quarter of the period and provides effective elimination of frequency error both in load modes and in damage modes.

AbstractEvent-related potentials (ERPs) extracted from electroencephalography (EEG) data in response to stimuli are widely used in psychological and neuroscience experiments. A major goal is to link ERP characteristic components to subject-level covariates. Existing methods typically follow two-step approaches, first identifying ERP components using peak detection methods and then relating them to the covariates. This approach, however, can lead to loss of efficiency due to inaccurate estimates in the initial step, especially considering the low signal-to-noise ratio of EEG data. To address this challenge, we propose a semiparametric latent ANOVA model (SLAM) that unifies inference on ERP components and their association with covariates. SLAM models ERP waveforms via a structured Gaussian process (GPs) prior that encode ERP latency in its derivative and links the subject-level latencies to covariates using a latent ANOVA. This unified Bayesian framework provides estimation at both population- and subject-levels, improving the efficiency of the inference by leveraging information across subjects. We automate posterior inference and hyperparameter tuning using a Monte Carlo expectation–maximization (MCEM) algorithm. We demonstrate the advantages of SLAM over competing methods via simulations. Our method allows us to examine how factors or covariates affect the magnitude and/or latency of ERP components, which in turn reflect cognitive, psychological, or neural processes. We exemplify this via an application to data from an ERP experiment on speech recognition, where we assess the effect of age on two components of interest. Our results verify the scientific findings that older people take a longer reaction time to respond to external stimuli because of the delay in perception and brain processes.

Engineers need to know properties of shallow marine sediments to build piers, pipelines and even offshore windfarms. We present a method for estimating the density, P velocity and thickness of these sediments. The traveltime inversion of primary and multiple reflections enables their semiquantitative estimation in marine surveys when using a minimal acquisition system such as a monochannel Boomer. Picking errors, ambient noise and interfering events lead to significant errors in the estimates. Similar, albeit milder, instabilities occur when inverting the signal amplitudes to determine the reflectivity of the layer interfaces. In this paper, we introduce a coupling between the separate inversion of amplitudes and traveltimes to obtain a better Earth model. The P velocity shows up in two stable terms provided by the separate inversions: the acoustic impedance of shallow sediments (through the amplitudes) and the transit time across the sediment layer (through the traveltimes). We couple the two inversion engines by imposing a smoothness condition on velocity and density and thickness of the layer while keeping the impedance and traveltime constant. We thus exploit the ambiguity of the solution to introduce geological criteria and reduce the noise contribution. We validated the proposed method with synthetic and real data. [ABSTRACT FROM AUTHOR]

Due to the joint development characteristic and macropore structure of loess, it is easy to cause structure collapse under earthquake or artificial vibration. The study on the loess disaster effect and its mechanism under earthquake action is insufficient due to its complexity. Hence, to study the deformation and mechanical properties more accurately, the dynamic characteristics of saturated remolded loess under cyclic dynamic load were tested using a GDS dynamic triaxial instrument in this paper. The test results show that strain and pore water pressure increase gradually at different rates with the development of vibration, and there is an obvious inflection point in the time-history curve of both. When the number of vibrations (N) exceeds this point, the strain increases rapidly, and pore water pressure tends to be stable. Under the action of large amplitude and low-frequency dynamic load, the strain and pore water pressure increase rapidly with fewer vibrations and the deviator stress (q) decreases rapidly, while the sample achieves damage faster with the increase of amplitude. During the application of a dynamic load, the effective stress (p) gradually decreases and its rate of change slows down. Finally, when the saturated remolded loess is subjected to a constant-amplitude dynamic load, the combination of large amplitude and low frequency leads to the failure of the sample in the shortest time. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Zhejiang University: Science A is the property of Springer Nature 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 crack initiation stress threshold is widely used in excavation industries as rock spalling strength when designing deep underground structures to avoid unwanted brittle failures. While various strain-based methods have been developed for the estimation of this critical design parameter, such methods are destructive and often requires subjective interpretations of the stress–strain curves, particularly in rocks with pre-existing microcracks or high porosity. This study explore the applicability of non-destructive ultrasonic through-transmission methods for determining rock damage levels by assessing the changes in transmitted signal characteristics during loading. The change in velocity, amplitude, dominant frequency, and root-mean-square voltage are investigated with four different rock types including marble, sandstone, granite, and basalt under various stress levels. Results suggest the rate of signal variations can be reliably used to estimate crack closure and crack initiation stress levels across the tested rocks before failure. Comparison of the results between the conventional techniques and the new proposed methods based on ultrasonic monitoring are further discussed. [ABSTRACT FROM AUTHOR]

With rapid urbanization and the structural transformation of economic development, cultivated land abandonment is becoming more serious, posing great threats and challenges to the security of food production. The rapid and accurate monitoring of cultivated land abandonment is of great value for ensuring regional and national food security. In view of the urgent need for abandoned land monitoring, we proposed a method to identify abandoned land based on the temporal features of optical time series data. First, the NDVI time series of cultivated lands was constructed using multitemporal Sentinel-2 data. The constructed NDVI time series was preprocessed to filter out outliers among the observations. Subsequently, the amplitude feature of the NDVI time series was extracted for cultivated land. We acquired the amplitudes of the abandoned and non-abandoned land samples and generated statistics for the range of amplitudes. We then extracted the optimal threshold of NDVI amplitude for separating abandoned land from non-abandoned land using two steps: initialization and optimization of the threshold. In the initialization step, the maximum NDVI amplitude among the abandoned land samples was set as the initial threshold. In the optimization step, the threshold was decreased in step of 0.01, and the F1-score was calculated iteratively to determine the optimal threshold. With a decrease in the threshold when the F1-score reached its highest value, the corresponding threshold was set as the optimal threshold. Accordingly, the rule for abandoned land recognition was constructed; namely, when the NDVI amplitude was lower than the optimal threshold, cultivated land was classified as abandoned land. Finally, based on the mapping results, landscape pattern indices were calculated to analyze the landscape pattern characteristics of abandoned lands. The proposed method was validated in Potou District, Zhanjiang City, Guangdong Province, China. The main results of the study were as follows: 1) Comparing the NDVI time series curves of abandoned and non-abandoned lands, we found that the NDVI time series curves of abandoned land changed gently, whereas the NDVI time series of non-abandoned land changed with great fluctuation due to the phenological process of crop growth. 2) By iteratively searching for the optimal NDVI amplitude, the optimal segmentation threshold of NDVI amplitude was 0.42 for distinguishing abandoned lands from non-abandoned lands in Potou. We used 100 abandoned and non-abandoned land samples to validate their accuracy. By using this optimal threshold, the overall recognition accuracy of abandoned land reached 91.83%, and the overall extraction accuracy of non-abandoned land reached 90.20%. 3) The calculation results of the landscape pattern index of abandoned lands revealed that these are generally small and have irregular shapes. Abandoned lands were scattered throughout Potou. This study demonstrates that the proposed method can effectively identify abandoned land using the amplitude of NDVI time series. This method can produce highly reliable abandoned land mapping and shows good potential for largescale agricultural applications. [ABSTRACT FROM AUTHOR]