Range Of Amplitudes Research Articles

High-fidelity lens-free on-chip microscopy via dual-channel noise separation

Lens-free on-chip microscopy (LFOCM) is a high-throughput computational imaging technique that enables high-resolution, label-free imaging without requiring complex optical systems. However, LFOCM encounters significant challenges in achieving high-resolution reconstructions due to noise accumulation. We propose a high-fidelity LFOCM method that integrates pixel super-resolution (PSR) with dynamic dual-channel noise separation (DCNS). This approach simultaneously separates the amplitude and phase noise during the reconstruction process, thereby improving noise robustness and enhancing the dynamic range of quantitative amplitude and phase imaging. Experimental validation across various sample types demonstrated the effectiveness of our method. DCNS achieves a resolution that exceeds 34.1% of the Nyquist–Shannon sampling limit, with a full field of view (FOV) of 28.6 mm2, improving the dynamic range of phase reconstruction and effectively suppressing artifacts that degrade the reconstruction quality, thus resolving the trade-off between noise reduction and resolution.

Bimodal Photothermal-driven Self-sustained Oscillator Based on MXene Structure

Soft robots capable of autonomous, continuous, fast, and adjustable motion speeds under constant external stimuli have great potential in environmental, industrial, military, and medical fields. Aiming at the difficulties of existing self-oscillators, including small oscillation range, difficulty of achieving non-reciprocal motion, and the slow forward speed of the resulting self-sustained soft robots. In this paper, a sunlight-driven self-oscillator based on MXene is prepared. By employing a bimorph structure and thermal regulation process, the self-oscillator exhibits two distinct oscillation modes: 'elastic' and 'plastic' deformation. These modes can be modulated within the same film by varying the light power. A broader amplitude range (3.6-302.3°, 3.3 times that of the existing studies) is achieved by attaching a load to the film's end to enhance the inertial force of movement. Non-reciprocal motion in both modes and stable oscillations in sunlight are achieved. Finally, a light-driven sailboat model is developed. The sailboat can achieve autonomous light-forward motion with a speed of up to 12.8 body length per minute (2.1 times that of existing studies), with its propulsion mechanism further explained through numerical simulation results. This research provides new strategies for constructing fast and large-amplitude self-oscillators and demonstrates the potential for applications in speed-adjustable autonomous forward devices.

Temporal properties of transcutaneous direct current motor conduction block.

Direct current (DC) electrical block of peripheral nerve conduction shows promise for clinical applications to treat spasticity, pain, and cardiac arrhythmias. Most previous work has used invasive nerve cuffs. Here we investigate the potential of non-invasive transcutaneous direct current motor block (tDCB). 

In anesthetized rats, force output from the tibialis and peroneus muscles was measured in response to stimulation proximally on the sciatic nerve. DC blocking waveforms were delivered via a surface electrode placed distally on the skin over the common peroneal nerve. The efficacy of the block was observed as the reduction/abolition of muscle force. Experiments using this model were performed with two different electrode types. A range of DC amplitudes and durations was used to elucidate the temporal properties of block.

Higher levels of DC resulted in a larger block percentage. The amount of time needed to induce block depended on the level of DC, with smaller amplitudes resulting in longer induction times. When block was applied for a longer period of time (120s), the block was sustained following DC delivery. This "recovery period" was longer for higher amplitudes of block. 

In addition to the block thresholds and temporal effects, two additional evaluations were made: In some animals the efficacy of tDCB to block tetanic muscle contractions was successfully verified. Finally, the effect of tDCB on nerve health was verified using a second distal electrode for comparison. 

In this study, tDCB has been shown to reversibly blocked action potentials in peripheral motor nerves. A lower amplitude applied for a longer duration could produce delayed complete block as well as delayed partial block. Also, a higher amplitude was associated with a longer recovery time. These temporal properties are important considerations for potential clinical applications.&#xD.

Elastic and Inelastic Energy Density in Cyclic Deformation of Iron-Based Layered Materials Over an Extended Range of Load Amplitudes

Elastic and Inelastic Energy Density in Cyclic Deformation of Iron-Based Layered Materials Over an Extended Range of Load Amplitudes

Linking structural and rheological memory in disordered soft materials.

Linking the macroscopic flow properties and nanoscopic structure is a fundamental challenge to understanding, predicting, and designing disordered soft materials. Under small stresses, these materials are soft solids, while larger loads can lead to yielding and the acquisition of plastic strain, which adds complexity to the task. In this work, we connect the transient structure and rheological memory of a colloidal gel under cyclic shearing across a range of amplitudes via a generalized memory function using rheo-X-ray photon correlation spectroscopy (rheo-XPCS). Our rheo-XPCS data show that the nanometer scale aggregate-level structure recorrelates whenever the change in recoverable strain over some interval is zero. The macroscopic recoverable strain is therefore a measure of the nano-scale structural memory. We further show that yielding in disordered colloidal materials is strongly heterogeneous and that memories of prior deformation can exist even after the material has been subjected to flow.

Thermogelation of nanoemulsions stabilized by a commercial pea protein isolate: high-pressure homogenization defines gel strength.

The impact of animal-based food production on climate change drives the development of plant-based alternatives. We demonstrate the use of colloidal thermogelation on a real nanoemulsion system to create structured gels that could be of interest for thermo-mechanical processing of next-generation plant-based food applications. We use a commercial pea protein isolate (PPI) without further purification to stabilize a 20 vol% peanut oil-in-water nanoemulsion at pH = 7 by high-pressure homogenization (HPH) and demonstrate the temperature induced gelation behavior of the nanoemulsion as a function of the HPH processing parameters. Bright-field and laser scanning confocal fluorescence microscopy reveals a diverse microstructure of the aqueous PPI dispersions, with a large amount of insoluble protein particles, cell-wall debris particles, and lipid inclusions. Sedimentation of particulates is prevented by HPH treatment and leads to a loss of the dispersion's thermogelation properties. The non-gelling PPI dispersion stabilizes nanoemulsions and the insoluble components of the PPI dispersions persist throughout the HPH processing. We perform a systematic rheological investigation of the effect of HPH processing on thermogelation and demonstrate that the number of HPH passes n and HPH pressure P control the average nanoemulsion droplet size measured by DLS at a 90° scattering angle. We show that the droplet size defines the final gel strength with a strong inverse dependence of the elastic modulus on droplet size. Furthermore, processing can lead to heterogeneously structured gels that yield over a large strain amplitude range.

A Triboelectric Nanogenerator Utilizing a Crank-Rocker Mechanism Combined with a Spring Cantilever Structure for Efficient Energy Harvesting and Self-Powered Sensing Applications

With the advancement of industrial automation, vibrational energy generated by machinery during operation is often underutilized. Developing efficient devices for vibration energy harvesting is thus essential. Triboelectric nanogenerators (TENGs) based on spring and cantilever beam structures show considerable potential for industrial vibration energy harvesting; however, traditional designs often fail to fully harness vibrational energy due to their structural limitations. This study proposes a triboelectric nanogenerator (TENG) based on a crank-rocker mechanism and a spring cantilever structure (CR-SC TENG), which combines a crank-rocker mechanism with a spring cantilever structure, designed for both energy harvesting and self-powered sensing. The CR-SC TENG incorporates a spring cantilever beam, a crank-rocker mechanism, and lever amplification principles, enabling it to respond sensitively to low-frequency, small-amplitude vibrations. Utilizing the crank-rocker and lever effects, this device significantly amplifies micro-amplitudes, enhancing energy capture efficiency and making it well suited for low-amplitude, complex industrial environments. Experimental results demonstrate that this design effectively amplifies micro-vibrations and markedly improves energy conversion efficiency within a frequency range of 1–35 Hz and an amplitude range of 1–3 mm. As a sensor, the CR-SC TENG’s dual-generation units produce output signals that precisely reflect vibration frequencies, making it suitable for the intelligent monitoring of industrial equipment. When placed on an air compressor operating at 25 Hz, the first-generation unit achieved an output voltage of 150 V and a current of 8 μA, while the second-generation unit produced an output voltage of 60 V and a current of 5 μA. These findings suggest that the CR-SC TENG, leveraging spring cantilever beams, crank-rocker mechanisms, and lever amplification, has significant potential for micro-amplitude energy harvesting and could play a key role in smart manufacturing, intelligent factories, and the Internet of Things.

Analysis and application of a 3D chaotic system with an extremely extensive range of amplitudes and offset boosting

Abstract The study of high-dimensional chaotic systems has been the subject of considerable research interest, whereas the complex characteristics of low-dimensional chaotic systems have been largely overlooked. A new dimensional (3D) chaotic system containing only two kinds of nonlinear terms is constructed based on the Lorenz system to enrich the theory of chaotic systems and improve the complex properties of low-dimensional chaotic systems. The system lacks a symmetric structure; however, under the influence of the symmetric parameter α, the system attains a symmetric state and can produce attractors with a symmetric structure. Under the parameter β, the system can realize the regulation of amplitude, frequency, and nonlinear offset boosting of three signals simultaneously. The parameter γ can realize the control of two signal amplitude and frequency at the same time. The system always remains chaotic when the parameters β and γ are varied in a great range. In addition, this 3D chaotic system has offset boosting behavior in arbitrary single and multiple directions, and the offset constant has a wide range of values. These features provide great convenience for secure communications and weak signal engineering applications. Further, analog circuit simulations and DSP (Digital Signal Processor) hardware circuits confirm the parametric modulation of the system and the offset boosting behavior in any direction. Moreover, taking advantage of the extensive offset range, a synchronization controller is designed for the drive and response systems. Finally, the modulation of offsets with a wide range of values realizes the encrypted transmission of binary digital information and lays the foundation for future engineering applications.

A Degradation Model of Electrical Contact Performance for Copper Alloy Contacts with Tin Coatings Under Power Current-Carrying Fretting Conditions

The fretting degradation of coating materials is complicated when the Joule heating effect of the load current is non-negligible. In this work, the fretting degradation behavior of tin-coated copper alloy contacts was examined across the current range from 5 A to 30 A and the fretting amplitude range from 200 μm to 400 μm. The uniform degradation process and associated mechanisms, including the wear-dominated stage, softening-dominated stage, and oxidation-dominated stage were recognized and interpreted explicitly. An innovative fusion model for the degradation of electrical contact performance, data-driven and based on physics mechanism, was proposed. The contact voltage was selected as the characterization variable and pre-processed by the threshold-crossing filter method and the Levenberg–Marquardt algorithm. The optimal degradation model, considering the coupled effects of current and fretting amplitude, was presented with the use of the support vector regression method. Finally, the prediction accuracy of the model was validated by experiment results.

Improved piezoelectric energy harvester with dual-impact strategy for small acceleration amplitude vibrations

Increasing the operable frequency range and improving the small acceleration amplitude harvesting performance of the piezoelectric energy harvesting devices is importance due to the wide frequency spectrum and large amplitude range of environmental vibrations. In this Letter, an improved piezoelectric energy harvester with frequency upconversion is proposed, which is comprised of a composite piezoelectric beam and a firing pin. In contrast to the conventional impact-based systems that mainly rely on beam vibrations to enhance harvesting performance, the proposed system employs a dual-impact strategy. In particular, an oblique impact-based harvesting phenomenon is observed, which has not been investigated in previous studies. A multilevel impact nonlinear coupled dynamic model is developed. The experimental results indicate that at an excitation acceleration amplitude of 0.15 g, the proposed system demonstrates a 482.9% increase in the output peak value and introduces dual-band frequency in comparison with the conventional structure. Additionally, the proposed coupled model is validated through adjustments to various load resistances. The highest output power is achieved at a load resistance of 210 kΩ, with the maximum average power reaching 3.96 mW and a power density of 1.59 mW/mm3g2 at an acceleration amplitude of 0.15 g, outperforming other piezoelectric energy harvesters.

Finite Element Analysis and Improved Evaluation of Mechanical Response in Large Oil Storage Tanks Subjected to Non-Uniform Foundation Settlement

This study developed a finite element model to address the issue of non-uniform settlement in large crude oil storage tanks. The model consisted of four key components: the tank foundation, bottom plate, wall plate, and large fillet welds. The Ramberg-Osgood model was used to describe the material’s nonlinearity. Key factors such as the radius-to-thickness ratio, height-to-diameter ratio, harmonic number, and amplitude were evaluated for their impact on the radial deformation of the tank’s top wall. Two numerical models were developed—one accounting for the coupling effect between the foundation and the tank bottom, and the other without it. The differences in radial deformation between these models were analyzed, revealing that deformation was minimally influenced by the radius-to-thickness ratio, but increased with higher height-to-diameter ratios and harmonic amplitudes. At low liquid levels, radial deformation increased with harmonic number, but at high levels, it decreased once the harmonic number exceeded four due to the decoupling of the tank bottom from the foundation. The model considering foundation coupling exhibited less radial deformation compared to the one neglecting it, particularly as the harmonic number and amplitude increased. An improved evaluation method identified a critical range of harmonic amplitudes for a 100,000 m3 tank, within which the coupling effect can be reasonably neglected, allowing deformation to be calculated using the simpler model.

On formation and breakup of jets during droplet impact on oscillating substrates

Droplet impact on substrates is the cornerstone of several processes relevant to many industrial applications. Imposing substrate oscillation modifies the impact dynamics and can, therefore, be used to control the ensuing heat, mass, and energy transfer between the substrate and the impacting droplet. Previous research has shown that substrate oscillation strongly influences the spreading behavior of the droplet. In this study, we extend this understanding to examine how substrate oscillations can further modulate the retraction dynamics of the droplet, consequently affecting its long-term behavior, with a particular focus on induced jetting and subsequent breakup. We systematically examine the breakup of jets formed by the recoiling droplet through experimental investigations across a range of oscillation frequencies and amplitudes. Our findings reveal two distinct jet breakup modes: early and late, each governed by different time scales. Subsequently, we present a mechanistic description of the jetting process. Furthermore, we derive a simple scaling analysis based on energy balance to identify the critical condition required for jet breakup. Finally, we compare the experimental data with the scaling analyses to show its efficacy.

Evaluation of Dynamic Properties of Sand Mixed with Expanded Glass Granules by Energy Concept Under Cyclic Torsional Loadings

In recent years, lightweight materials have gained attention for their numerous benefits, including cost reduction, insulation, and bearing capacity. Expanded glass granules (EGG) stand out among these materials, showing significant potential in geotechnical engineering applications. This study examines the potential use and feasibility of a SAND-EGG mixture in geotechnical applications through cyclic torsional shear test for measuring shear strength, modulus reduction, and energy dissipation. This is conducted on the unmixed dry specimens (Reference Sand, EGG) and the mixed dry specimens by mass (1, 2%) and volume (5, 10, 15%) under 100 kPa effective pressure. The test also conducted along 0.02%–0.5% shear strain amplitudes for both samples group. An energy-based approach is used to analyze mixed material's capacity for energy dissipation, a crucial factor in determining seismic resistance during cyclic loading. The impact of employing EGG on modulus reduction behavior was also explored concerning energy dissipation. Considering the results, it is show that the use of EGG increases the resilience with high friction capacity and by taking up a significant portion of the available void ratio and provides lightness in geotechnical applications in examined shear strain amplitude range (0.02%–0.5%).

Extreme Environmental Variability Induces Frontloading of Coral Biomineralisation Genes to Maintain Calcification Under pCO2 Variability.

Corals residing in habitats that experience high-frequency seawater pCO2 variability may possess an enhanced capacity to cope with ocean acidification, yet we lack a clear understanding of the molecular toolkit enabling acclimatisation to environmental extremes or how life-long exposure to pCO2 variability influences biomineralisation. Here, we examined the gene expression responses and micro-skeletal characteristics of Pocillopora damicornis originating from the reef flat and reef slope of Heron Island, southern Great Barrier Reef. The reef flat and reef slope had similar mean seawater pCO2, but the reef flat experienced twice the mean daily pCO2 amplitude (range of 797 v. 399 μatm day-1, respectively). A controlled mesocosm experiment was conducted over 8 weeks, exposing P. damicornis from the reef slope and reef flat to stable (218 ± 9) or variable (911 ± 31) diel pCO2 fluctuations (μatm; mean ± SE). At the end of the exposure, P. damicornis originating from the reef flat demonstrated frontloading of 25% of the expressed genes regardless of treatment conditions, suggesting constitutive upregulation. This included higher expression of critical biomineralisation-related genes such as carbonic anhydrases, skeletal organic matrix proteins, and bicarbonate transporters. The observed frontloading corresponded with a 40% increase of the fastest deposited areas of the skeleton in reef flat corals grown under non-native, stable pCO2 conditions compared to reef slope conspecifics, suggesting a compensatory response that stems from acclimatisation to environmental extremes and/or relief from stressful pCO2 fluctuations. Under escalating ocean warming and acidification, corals acclimated to environmental variability warrant focused investigation and represent ideal candidates for active interventions to build reef resilience while societies adopt strict policies to limit climate change.

Left atrial spatial entropy: a novel tool for electrophysiological substrate characterization in atrial fibrillation.

Electrical remodeling has been linked to the progression and recurrence of atrial fibrillation (AF) after catheter ablation (CA). Substrate mapping based solely on a voltage amplitude electrogram (EGM) does not provide a comprehensive understanding of the left atrial (LA) disease. The aim of this study is to assess left atrial spatial entropy (LASE) from voltage maps routinely obtained during AF ablation to further characterize the LA substrate. High-density electroanatomic maps (EAMs) of 27 patients with paroxysmal or persistent AF undergoing routine CA were prospectively collected. Computational post-processing was performed on the voltage maps. Using the Shannon entropy model, the probability distribution of the amplitude range values associated with each point of the map was used to measure LASE. Finally, correlations between LASE and clinical and electrophysiological characteristics of AF were explored. LASE differentiated between patients with paroxysmal and persistent AF (6.45 ± 0.41 vs. 5.87 ± 0.53; p = 0.028) and patients with normal and abnormal LA substrate (6.42 ± 0.42 vs. 5.87 ± 0.56; p = 0.043), independent of the basal rhythm during EM acquisition (6.33 ± 0.41 vs. 6.11 ± 0.63; p = 0.619). Accordance between LASE and EAMs was assessed by ROC analysis (AUC: 0.81; C.I.: 0.62-0.99; Youden index: 6.06; sensitivity: 80%; and specificity: 80%). Patients with the lowest LASE reported AF recurrence at the follow-up. LASE may play a role in the further characterization of the LA substrate and the type of AF, independent of basal rhythm.

State primary special standard of impulse current unit in the range from 1.0 to 1.0·105 A GET 202-2024

Metrological assurance of immunity tests to impulse currents of natural and artificial origin is an urgent task in the development and production of aviation, rocket and space equipment and telecommunication equipment. The State primary special standard of lightning discharge impulse current unit GET 202-2012 provided the unity of measurements of impulse current parameters in the amplitude range from 1 to 100 kA and the time range from hundreds of nanoseconds to units of milliseconds. In order to provide metrological support for measuring instruments for impulse currents of electrostatic discharges and switching currents (rise time of the transient response of at least 1 ns, measurement range from 1 to 200 A), GET 202-2012 underwent a modernization cycle in 2020–2023. As a result of the modernization, the State Primary Special Standard of the unit of pulse current in the range from 1.0 to 1.0·105 A GET 202-2024 was approved, the lower limit of the range of reproduction of the unit of pulse current of which was 1 A with a pulse front duration of no more than 1 ns. Thus, the problem of ensuring the uniformity of measurements of electrostatic discharges and power switching impulse currents parameters was solved. To achieve the specified characteristics, GET 202-2024 includes devices for reproducing current pulses based on semiconductor keys and reference current shunts with a short rise time. The composition, structural diagram, technical and metrological characteristics of GET 202-2024 are given. GET 202-2024 ensures the uniformity of measurements of the parameters of pulse currents of electrostatic discharges, partial lightning discharges, as well as pulse currents generated by switching processes when solving problems of electromagnetic compatibility, creating new types of materials and coatings, in geophysical and meteorological research and observations, in healthcare.

The effects of dynamic factors inside the bubble on sono-hydrogen yield: A numerical study

The formation of H2 by introducing ultrasonic waves to liquid has been widely recognized as a way to provide a clean, efficient, and reliable source of H2, known as Sono-Hydro-Gen. H2 comes from the chemical effects of ultrasonic waves (sonochemistry) caused by the growth and collapse of acoustic cavitation bubbles. In this work, the effects of dynamic parameters (i.e., bubble temperature, the amount of water vapor trapped inside the bubble, and collapse time) in the evolution of cavitation bubbles on H2 production are studied numerically. For an oxygen bubble, computational simulations are performed for the wide range of acoustic amplitudes (1.5–3 atm), ultrasonic frequencies (140–515 kHz), and ambient radii (0.25–20 μm), considering 22 reversible chemical reactions and 10 chemical species inside the bubble. The numerical results show that the amount of water vapor has a significant effect on the bubble collapse temperature. At low excitation amplitudes, the amount of water vapor is not enough to cause the bubble to form a strong collapse. Nevertheless, at high excitation amplitudes, the amount of water vapor is too much to reduce the bubble temperature. There exist optimal values of bubble temperature and amount of water vapor for H2 production. The optimal bubble temperatures are 5267, 4813, 4626, and 3856 K, corresponding to H2 productions of 4.21 × 10−18, 1.29 × 10−18, 2.61 × 10−19, and 8.48 × 10−20 mol, respectively, at ultrasonic frequencies of 140, 213, 355, and 515 kHz. No matter what the excitation parameters are, the optimal water vapor fraction is 0.78 ± 0.04 for H2 production. The obtained results of the present work can provide guidelines for H2 production in acoustic cavitation.

Novel Fluidic Oscillator Evaluation Considering Dimensional Modifications

Although flow mixing and cooling can be greatly enhanced when considering the use of fluidic oscillators (FOs), they are more commonly employed in active flow control (AFC) applications where the injected pulsating flow interacts with the boundary layer, usually in order to delay its separation. In fact, prior to any FO implementation in a given application, it is essential to study the range of frequencies and amplitudes it can generate as a function of the incoming mass flow and its dimensions. This is what is being performed in the present manuscript for a rather novel FO configuration. A numerical study of a standard three-dimensional (3D) FO configuration, and also using a two-dimensional (2D) approach, is initially presented. After comparing the 3D and the 2D results and analyzing the main differences, we modified some of the internal dimensions of the FO in order to evaluate the variation in its dynamic performance. The present results clarify which internal dimensional modifications are more effective in generating larger output frequencies and velocity field variations. Care is taken to analyze the origin of self-sustained oscillations. This paper links, for the first time, the origin of the pressure force oscillations at the feedback channel’s outlet, with the interaction of the mixing chamber central jet and the reverse feedback channel flow at the mixing chamber’s converging walls. A novel equation relating the FO outlet mass flow frequency with the time-averaged FC reverse flow is presented and discussed. In fact, the present study needs to be seen as the continuation of a former one, recently published by authors, where the effects of several Reynolds numbers as well as some different internal dimensions were considered.

Acceleration is the key to drag reduction in turbulent flow

A turbulent pipe flow experiment was conducted where the surface of the pipe was oscillated azimuthally over a wide range of frequencies, amplitudes, and Reynolds numbers. The drag was reduced by as much as 35%. Past work has suggested that the drag reduction scales with the velocity amplitude of the motion, its period, and/or the Reynolds number. Here, we find that the key parameter is the acceleration, which greatly simplifies the complexity of the phenomenon. This result is shown to apply to channel flows with spanwise surface oscillation as well. This insight opens potential avenues for reducing fuel consumption by large vehicles and for reducing energy costs in large piping systems.

Vibration-resonance chimeras in coupled excitable systems with heterogeneous aperiodic excitations

In this work, we present a novel chimera-like state known as the vibration-resonance chimera (VRC) state, which is induced by heterogeneous aperiodic (HA) excitations and emerges within the optimal range of amplitude for the HA excitations. We investigate the dynamic behaviors of the FitzHugh-Nagumo model in relation to HA excitations and coupling strength in parameter spaces, identifying specific regions where VRC states exist and analyzing the transition mechanisms between different dynamic behaviors. Using basin stability measures, we find that the mean period of HA excitations affects the multi-stable states of neural systems. Specifically, the model excited by HA excitations with a larger mean period is more likely to exhibit multi-stable states. Additionally, we explore the effects of two levels of heterogeneity in HA excitations, namely amplitude heterogeneity and period heterogeneity, on VRC states. Amplitude heterogeneity can suppress the occurrence of VRC states, whereas period heterogeneity can promote their generation. This work provides valuable insights into complex system dynamics, enhancing our understanding of chimera states in neuronal models and their potential applications in neural networks.