The photomagnetic behavior of a mixed-valence heptanuclear complex [Fe(II)(CN)6{Fe(III)L}6](SCN)2, where L = dianion N,N'-bis(1-hydroxy-2-benzyliden)-1,7-diamino-4-azaheptane, has been investigated. The structure of the complex was optimized using density functional theory with the def2-SVP basis set and the Tao-Perdew-Staroverov-Scuseria functional. Continuous wave (CW) and time-resolved electron paramagnetic resonance (TR EPR) spectroscopy measurements at low temperatures (20-65K) reveal a reversible, light-induced change in EPR signal intensity, indicating photoswitching between high-spin and low-spin states. The analysis of the CW and TR EPR spectroscopy results identified two types of effects related to sample magnetization: local sample heating by light and magnetization changes associated with photoinduced high-spin to low-spin transitions. These results demonstrate the potential of this complex as a photoswitchable magnetic material.

Accurate measurement of ocean wave parameters is paramount for offshore engineering design and marine environmental monitoring. Distributed pressure sensing technology provides a robust data foundation for analyzing the spatio-temporal characteristics of wave fields through synchronized observations at multiple stations. However, multi-sensor data exhibit high-dimensional spatio-temporal coupling, posing significant challenges for traditional single-point signal processing methods in capturing the topological associations between measurement sites. To address these limitations, this study develops a framework for spatio-temporal feature modeling and wave height reconstruction based on Graph Neural Networks (GNNs). The proposed framework integrates the spatial configuration of sensor arrays with graph-theoretic topological representations. By fusing geometric distances and signal correlations, an adaptive adjacency matrix is constructed to establish a dynamically adjustable graph structure. On the feature extraction level, a spatio-temporal fusion method combining multi-scale graph convolutions and gated temporal modeling is proposed. The experimental results obtained on the Blancs Sablons Bay multi-sensor dataset demonstrate that the proposed method significantly outperforms traditional approaches, achieving lower prediction errors and validating the effectiveness of graph-structured modeling in distributed wave sensing.

The purpose of the study is to analyze the value of wave damping by the thickness, density, and resilience of the supporting roots of Rhizhophora sp. mangrove as a wave damper. The method used in the study is the transect-squared method and laboratory tests. Wave measurements were done using SBE 26 during the highest waves. The value of ΔE (%) at Dewi Mandapa Beach rised from 10.74% to 92.79% at a thickness of 5 meters to 50 meters, while at Tanjung Putus Beach rised from 26.23% to 92.41% at a thickness of 5 meters to 30 meters. It is stated that the relationship between them is directly proportional. The root resilience value decreased from 3.1331 (J/m2) to 2.4059 (J/m2), while the energy damping value increased from 3.7578E-04 (J/m2) to 5.5943E-04 (J/m2) at a thickness of 5 meters to 30 meters. It is stated that the relationship of root resilience with wave energy attenuation is inversely proportional. It is concluded that high-density Rhizophora sp. mangroves have substantial wave damping ability as a result of the bounciness of the supporting roots.

Type III solar radio bursts trace electron beams escaping from flares onto interplanetary magnetic fields, yet unambiguous source identification and continuous beam tracking remain challenging. We analyze a Type III event associated with a compact flare in NOAA AR 12887 studied with an unusually complete set of observables: X-ray imaging of the flare site, radio spectro-polarimetry with direction-finding, and multi-point in-situ particle and wave measurements. This synergy delivered two key results. (1) We identify the burst's solar source region by combining the timing consistency between the flare evolution and the radio onset (after accounting for light-travel time) with the sense and degree of circular polarization. The polarization is consistent with emission on topologically open (or quasi-open) field rooted in a compact EUV arcade, as expected for outward-propagating o/x-mode radiation in a diverging flux system. (2) We localize the electron beam and follow its spatio-temporal evolution into the heliosphere by triangulating radio directions and correlating them with time-of-flight signatures in the in-situ electron data. The accompanying Langmuir-wave measurements constrain the characteristic cross-section of the guiding flux tube via the spatial coherence and bandwidth of the wave packets, providing an empirical estimate of the beam's aperture. The magnetic context of AR 12887 shows a complex photospheric field with adjacent open corridors. This configuration could explain the rapid magnetic connectivity between a compact EUV arcade and interplanetary space, and clarifies why strong polarization can arise even when closed loops are present nearby. Together, these observations establish an end-to-end linkage from flare energy release to heliospheric propagation and provide a template for future coordinated studies that require coincident timing, imaging, polarization, radio direction-finding, and in-situ diagnostics to resolve electron escape pathways.

Auroral emissions play a critical role in coupling the magnetosphere and atmosphere at magnetized planets. At Jupiter, isolated auroral patches equatorward of the main auroral oval have been associated with magnetospheric injections, yet the key conditions driving these emissions remain unclear. Here we combine in situ particle and wave measurements and remote-sensing auroral observations from Juno to uncover the origins of Jupiter's patchy aurora. By examining both low-altitude and equatorial crossings, our results reveal that not all injections lead to auroral enhancements. Instead, auroral patches arise directly from electron precipitation driven by wave-particle interactions, while injections play a supportive role in facilitating wave growth and electron precipitation. These findings highlight the central role of plasma waves in auroral generation and in coupling Jupiter's magnetosphere and ionosphere, providing broader implications for wave-driven auroral processes across planetary magnetospheres.

Upcoming cosmic microwave background (CMB) experiments aim to detect primordial gravitational waves with unprecedented sensitivity. Effective foreground removal is essential to avoid biases in the measurement of the tensor-to-scalar ratio (r) in this high-precision regime. Recent analyses highlight the unexpected complexity of synchrotron emission at low frequencies, underscoring the need for more sensitive low-frequency data. To address this challenge, the European Low-Frequency Survey (ELFS) initiative and the Simons Array collaboration propose installing two European low-frequency receivers on one of the Simons Array telescopes. These receivers will enable measurements in the Southern Hemisphere between 6 and 20 GHz, complementary to those of current and proposed experiments targeting the measurement of cosmological gravitational waves. In this work, we study the benefits of combining these low-frequency observations with a representative future CMB experiment operating from the Southern Hemisphere. We find that the extra information can improve the knowledge of the underlying synchrotron spectral energy distribution (SED), with positive impacts on the robustness of measurement of the tensor-to-scalar ratio, r, against the complexity of low-frequency foregrounds.

Abstract In this study, we combine Cassini fields and particle observations to investigate Titan's induced magnetosphere from the TA to T82 flybys, including flybys from the Cassini prime, equinox, and part of the solstice mission, to investigate the average location and the shape of Titan's induced magnetosphere. Although earlier studies have provided valuable information on Titan's induced magnetosphere, they were largely based on separate analyses of fields and particle data. We provide an integrated map of electron density and temperature in Titan's near plasma environment to outline the external boundary of the induced magnetosphere. We identify a dense ionospheric region and an extended plasma wake with electron densities ranging between and c. In addition, we systematize the spatial distribution of pick‐up ions at Titan with respect to the background convective electric field. We indicate that pickup ions are found in the positive hemisphere of the Kronian plasma convective electric field. The mass of the observed pickup corresponds to methane group ions, ions as well as protons and molecular hydrogen ions. The Kronian background electric field progressively accelerates these ions, and we estimate its intensity by reconstructing the radial energy gain of this population in response to the convective electric field. We find the estimated from the pickup ions electric field values within 0.05 mV and 1.92 mV range, which is consistent with an estimate of 0.61 mV deduced from computation.

Experimental and numerical studies on interface debonding visualization for a rectangular CFST column with surface stress wave measurement and a threshold-based probability imaging algorithm

HF radar systems are used in many parts of the world as a part of operational coastal ocean observing systems. Their primary product is surface current mapping from the coast to a range determined by radio frequency and environmental conditions. Initiatives to promote their use for wave measurement are now being developed. Obtaining reliable wind measurements has proved more difficult primarily because there is no direct physical relationship between the radar signal and the wave field. In this paper, a machine learning approach, previously demonstrated for radar data at the location of an in situ measurement, has been extended to allow for wind mapping using wind model data for training. Using data from three different radar deployments operating at different frequencies, a single machine learning model has been developed that can be applied to all three locations. A subset of the model data is used in the training and testing of the method, and accuracy is assessed using a mix of these data and data at all model positions within the radar field of view. The results show that the new wind speed measurements are significantly more accurate than those previously available using an inverse wind-wave model. Radar wind maps are consistent with, although show more spatial variability than, model or satellite winds. More validation with offshore wind masts is recommended.

ABSTRACT The influence of surface roughness on the reflection and transmission of ultrasonic waves was investigated through an integrated theoretical–experimental approach. In the theoretical model, both the transducer surface and the rough interface are reconstructed using pseudo-random samples from a Quasi-Monte Carlo (QMC) method, and the ultrasonic wave fields are then calculated using mathematical expectations. Consequently, the roughness-induced attenuation of reflection and transmission coefficients is quantitatively assessed by comparing results obtained from rough versus smooth surfaces. The proposed approach optimally balances accuracy and computational efficiency, enabling high-fidelity simulation of the entire ultrasonic propagation process to systematically analyze how system parameters and inspection conditions influence measurement accuracy. Simulations show that increased surface roughness increases errors in reflection-based attenuation estimates; however, these errors can be reduced by using transmission-based attenuation or larger transducers. Moreover, in the case of a curved interface, the apparent attenuation of the reflection coefficient is reduced owing to enhanced diffraction effects, and the roughness-induced attenuation is accurately quantified by the proposed method. All major theoretical predictions are corroborated by experimental data, demonstrating the robustness and practical relevance of the approach for quantitative ultrasonic nondestructive evaluation of solid structures with rough surfaces.

Abstract Distributed acoustic sensing (DAS) is an emerging oceanographic technique in which an interrogator continuously records nanoscale strain of a fiber-optic cable, such as a telecommunication cable, with meter-scale measurement spacing over tens of kilometers. Empirical methods have recently been established for calculating pressure spectra to measure ocean surface gravity wave statistics from DAS strain. Here, we compile data from six submarine DAS experiments to provide a comparison between studies and establish recommendations for using DAS to measure ocean waves. Data were collected from Alaska, Hawaii, Massachusetts, North Carolina, and Oregon, United States, with different interrogators on different cable types in 0–60 m of water with 0–4 m of burial. Ground-truth measurements of ocean waves were provided by standard near-bed or sea surface instruments. The raw strain recorded in each experiment varied over four orders of magnitude, which could not be explained by water depth, wave conditions, or interrogator settings and suggests that cable characteristics and burial depth are important factors controlling strain magnitude and measurement quality. Strain spectra were converted to near-bed pressure spectra using a frequency-dependent, location-specific empirical correction factor, and DAS-derived pressure spectra were used to calculate wave statistics. The correction factors varied over 10 orders of magnitude between sites yet provided accurate calculations of wave height and period (root-mean-square error of 0.2–0.6 m for H s and 0.2–1.6 s for T e and T p ). The volume of data necessary for calibration is discussed. This meta-analysis highlights future oceanographic applications of DAS. Significance Statement Distributed acoustic sensing (DAS) is an emerging technology for measuring ocean waves on seafloor fiber-optic cables, such as telecom cables. The advantage of DAS is that it can record thousands of measurements per second at meter-scale spacing over tens of kilometers. We compare six datasets to characterize DAS-derived strain for measuring ocean waves. The differences in strain magnitude observed between datasets were not explained by water depth, wave height or period, or instrument settings. It is likely that cable composition and depth of burial control the magnitude of the recorded strain. Despite these differences, each dataset was empirically calibrated to produce accurate measurements of wave statistics. DAS is a promising new oceanographic technology, and new applications should be explored.

A signal acquisition and processing method for phase velocity measurement of qS and qP waves from S-wave trirefringence in stressed steel plates

Electroencephalogram (EEG) analysis explores brainwave changes resulting from Vedic chanting (VC) in this experimental study. In this study participants received Vedic recitations from the Rig Veda (RV), Yajur Veda (YV), Sama Veda (SV), and Atharva Veda (AV) which were evaluated through alpha wave (8-12 Hz) measurement to evaluate relaxation response effects known to cause cognitive relaxation and mindfulness. The research captured EEG signals from twenty participants who belonged to four age categories between twenty and fifty years using a fourteen-channel EEG recording system. The signals underwent wavelet-based denoising procedures and Gabor transform (GT) enabled their spectral analysis. Scientists calculated the relaxation factor (RF) for understanding Vedic chant effects on human beings. Vedic Sama provided maximum relaxation effects leading to a 25% RF enhancement whereas YV produced a 20% increase and RV generated 15% enhancement and AV yielded 10% relaxation. The participants between 30 and 45 years old experienced the largest relaxation effects yet their left-brain hemisphere enhanced alpha waves stronger than their right brain region. The statistical methods supported that these results showed meaningful variations. Neural relaxation results from VC practice according to research evidence which shows SV provides the most powerful relaxation effects.

Measurements of wave–particle interactions are important for the scientific understanding of various plasma phenomena. Laser-induced fluorescence techniques provide non-intrusive, spatially resolved information on the plasma response to electrostatic perturbations. Employing this technique to diagnose plasma fluctuations in dipole magnetic fields can provide insight into wave–particle interactions, mode conversion, and wave reflection and absorption. Externally driven ion acoustic waves are diagnosed as they propagate through the magnetic field gradient in the equatorial region of a permanent magnet. Evidence of reflected waves and strong ion responses is presented for a range of wave frequencies. Results are compared to other observational, simulated, and experimental works.

ABSTRACT We propose a non‐invasive pulse wave monitoring system that integrates a fully printed, partially stretchable ferroelectric electronic tattoo (e‐tattoo) sensor with a soft, elastomer‐encapsulated, partially stretchable data transmission unit (DTU). The DTU includes a rechargeable battery, Bluetooth‐enabled wireless data transmission, and optimized signal conditioning circuitry for the e‐tattoo sensor. We demonstrate: 1) a simple, printing‐based fabrication process for the e‐tattoo sensor and its integration with the DTU; 2) significant improvement in pulse wave index accuracy through optimized electrode material selection used in the e‐tattoo sensor (e.g., reduction in relative error of relative crest time index from 56.3% to 0.2%); 3) enhanced sensitivity via integration of the e‐tattoo on the DTU's soft encapsulation (increased from 25 pC/N to 1277 pC/N); and 4) successful extraction of clinically relevant pulse indices from radial artery of a human study subject.

Abstract Electric field instruments function by electrically coupling to the surrounding plasma, resulting in a response function that varies depending on local conditions. This variable coupling can complicate quantitative interpretation of wave measurements, yet is rarely considered. While this effect has recently been quantified for the Van Allen Probes, we present the first quantitative analysis for the Magnetospheric MultiScale (MMS) mission. First, MMS observations are evaluated against Faraday's Law, revealing that the angle between the measured whistler‐mode electric and magnetic fields directly depends on the wave propagation direction, a feature consistent with sheath impedance effects. A novel technique for determining electric field observations along each measurement direction is introduced, addressing limitations of previous works. This reveals that, for MMS in low‐density plasma, spin‐plane amplitudes are ∼60% of expected values, with small phase shifts, while spin‐axis measurements are accurate within 5%–10%, with phase shifts up to −20°. At intermediate densities, spin‐plane amplitudes match, or slightly exceed, expected values whereas spin‐axis observations can be overestimated by 70% and experience frequency‐dependent phase shifts. At high‐density, spin‐plane measurements generally agree with expected values, but spin‐axis observations are overestimated by ∼30% and experience ∼30°phase shifts. Accurate measurements are critical, with electric field fluctuations increasingly being used to infer wave‐particle energy exchange rates. If electric field observations can be under or over‐measured depending on the local plasma environment, this directly impacts these computations of energy exchange rates, potentially leading to a misinterpretation of the fundamental physical mechanisms that drive particle dynamics.

Summary Cementing plays a critical role in ensuring zonal isolation and long-term well performance, motivating continued evaluation of supplementary cementitious materials (SCMs) to partially replace Portland cement while maintaining oilwell operability and sealing-relevant properties. With this study, we examine the effect of partial replacement of Class G oilwell cement with fly ash (FA) across a range of blend compositions under controlled laboratory conditions. Five cement systems containing 0%, 20%, 40%, 60%, and 80% FA by weight of binder (BWOB) were prepared at a constant water content of 44% BWOB and conditioned at 150°F. An integrated experimental framework was adopted in which all blends were first screened using unconfined compressive strength and splitting tensile strength measurements after 24 hours curing, followed by a detailed characterization of the selected formulation using fresh-state performance, elastic response, and microstructural indicators. Fresh-state testing included rheology, thickening time, free water, and high-pressure, high-temperature (HPHT) fluid loss to assess placement-related behavior. The 60:40 ordinary Portland cement (OPC)/FA blend exhibited mechanical performance comparable to neat cement, with compressive and tensile strengths of 4,873 psi and 587 psi, respectively, while providing improved slurry stability, extended thickening time, and reduced fluid loss. Density profiling and X-ray computed tomography (CT) indicated reduced segregation and improved internal homogeneity, accompanied by a decrease in porosity from 32.3% to 29.8%. Elastic wave measurements showed modest increases in dynamic Young’s modulus and Poisson’s ratio relative to neat cement. The results demonstrate that moderate FA substitution can maintain key operational and mechanical criteria while enhancing slurry stability and microstructural uniformity, supporting its consideration in laboratory-scale formulation screening for oilwell cementing.

The Stueckelberg wave equation is transformed into a quantum telegraph equation and a set of stationary states is obtained as unitary solutions. As it has been shown previously that this PDE relates to the Dirac operator, and on the other hand it is a linearized Hamilton–Jacobi–Bellman PDE, from which the Schrödinger equation can be deduced in a nonrelativistic limit, it is clear that it is the key equation in relativistic quantum mechanics. We give a Bayesian interpretation for the measurement problem. The stationary solution is understood as a maximum entropy prior distribution and measurement is understood as a Bayesian update. We discuss the interpretation of the single electron experiments in the light of finite speed propagation of the transition probability field and how it relates to the interpretation of quantum mechanics more broadly.

Abstract Probe-to-wafer contact (PWC) has often been overlooked in on-wafer nonlinearity measurements of radio frequency surface acoustic wave (SAW) and bulk acoustic wave devices, yet the authors’ experience indicates that it can significantly distort the results. This work demonstrates that PWC introduces non-negligible nonlinear products, which are correlated with electrode surface oxidation and contact impedance. To characterize this effect, a nonlinear modified Butterworth–Van Dyke model incorporating PWC nonlinearity is proposed, which well fits the measured second- and third-order harmonic spectra of a temperature-compensated SAW resonator. For the first time, we reveal the critical role of PWC nonlinearity in nonlinear measurement, providing a solid basis for reliable on-wafer nonlinear characterization of acoustic devices.

Abstract We investigate the infinite potential well model in five modern physics textbooks widely used in undergraduate courses. We find that the textbooks utilize mechanical systems and electrical circuits, incorporating metaphorical terms to introduce the model, but they do not provide a clear explanation of the quantum nature of these systems and the requirements of quantum mechanics. In addition, the textbooks often inappropriately mix indeterministic and deterministic perspectives when explaining wave functions and measurement outcomes. Moreover, the textbooks present inaccurate descriptions, such as discrete momentum spectra, which rely on the de Broglie relation or the classical relation between kinetic energy and momentum. We finally suggest an appropriate scope of quantum mechanics concepts that the infinite potential well model can address and discuss the implications of our findings for teaching and learning at the introductory level.