Wave Parameters Research Articles

Effect of rare earth substitution on electromagnetic and microwave absorption properties of nickel-cobalt nano ferrite

Oxygen vacancy engineering is one of the most effective strategies for tuning the microstructural properties of oxide nanomaterials. However, the connection between oxygen vacancies and electromagnetic (EM) wave absorption capacities is unclear. Herein, oxygen vacancy-boosted microwave absorption is realized over Gd-doped Ni0.5Co0.5Fe2O4 (NCFO) nanoceramics. All magnetic properties are studied with the influence of induced lattice strain. Except for Ni0.5Co0.5 Gd0.075Fe1.925O4 (NCFOG3), which has an elevated saturation magnetization (Ms) of 63 emu/g, the Ms decreases with increasing Gd content. In addition, remnant magnetization (Mr), coercivity (Hc), and anisotropic constant (K) increased until Ni0.5Co0.5 Gd0.050Fe1.95O4 (NCFOG2) and then declined. The EM wave parameters: dielectric permittivity (ϵ'), magnetic permeability (μ'), dielectric loss (ϵ''), and magnetic loss (μ'') are systematically examined and found in the ranges of 2.07–3.5, 1.73–4.7, (4 × 10-2) – (2.2 × 10-1) and 0.18–0.35 respectively. Our finding shows that a small amount of Gd favors the high oxygen vacancy concentration, an appropriate lattice defect, and high magnetic and dielectric losses. The possible mechanism for EM wave absorption revealed the largely localized electrons and dipole centers created by the numerous oxygen vacancies causing the multiple reflection and scattering, which enhanced conductive loss, defect, and dipole polarizations. The maximum reflection loss (RL) -28.37 dB is observed at 17.80 GHz of a 2 mm thick sample for NCFOG3. This research reveals a distinct link between oxygen vacancy defects and EM wave dissipation capability, providing important information for developing better EM wave absorbents.

Machine learning-based evaluation of application value of traditional Chinese medicine clinical index and pulse wave parameters in the diagnosis of polycystic ovary syndrome

IntroductionPolycystic ovary syndrome (PCOS) is a prevalent endocrine disorder in women that often leads to ovulatory infertility. This study aims to establish and validate an effective predictive model for PCOS and to explore the correlation of features between patients with irregular menstruation and those with PCOS, using pulse wave parameters and traditional Chinese medicine (TCM) clinical indices. MethodsFrom August 2018 to January 2022, women with irregular menstruation were enrolled in this study. Subjects who met the inclusion criteria were categorized into PCOS and non-PCOS groups based on diagnostic criteria. Pulse wave parameters and TCM clinical indices were collected by two medical professionals. After data cleaning, recursive feature elimination with cross-validation (RFECV) was used for feature selection. Four supervised machine learning classifiers were used to build PCOS prediction models, including Extra Trees (ET), Random Forest (RF), Extreme Gradient Boosting (XGB/XGBoost), and Support Vector Machine (SVM). The SHapley Additive exPlanation (SHAP) values based on the optimal model were visualized for further feature explanation. ResultsA total of 450 women with irregular periods were enrolled in the study, consisting of 294 patients with PCOS and 156 without PCOS. Based on RFECV, 31 features, including 12 pulse parameters and 19 TCM clinical indices, were selected for building prediction models. Using pulse and TCM clinical index was superior to using pulse parameters or TCM clinical index alone in prediction. SVM achieved the best PCOS prediction results (accuracy=0.837, AUC=0.878, F1 score=0.878). For pulse parameters, lower values of right As, right h4, left h1, left h3, left h5, left w/t, and higher right t5 showed an obvious positive PCOS predictive effect. Women with PCOS were more likely to experience delayed menstruation, negative emotions, a slightly jelly-like menstrual texture, higher BMI, and a TCM assessment of greasy tongue coating. ConclusionA PCOS prediction model based on the SVM algorithm was established and verified as the best model for distinguishing between patients with PCOS and patients without PCOS with irregular menstruation. The new prediction model that uses pulse wave parameters and TCM clinical indices offers a non-invasive and cost-effective way to diagnose PCOS, and the model provides objective evidence for TCM diagnosis.

Variability of non-breaking surface-wave induced mixing and its effects on ocean thermodynamical structure in the northwest Pacific during Typhoon Lekima (2019)

The surface waves, which contain most of the mechanical energy in the upper ocean, greatly contribute to the vertical mixing processes. Two of the non-breaking wave-induced physical processes, including wave-generated turbulence and residue of wave transport flux, are introduced as two mixing schemes, and incorporated into the ocean circulation model to study the effects on the upper ocean during the Typhoon Lekima (2019). The new vertical diffusion terms, corresponding to the wave-induced mixing processes, can be calculated directly based on the simulated surface wave parameters from wave spectrum model. Four numerical experiments are designed for analysis and comparison of the temperature and current in the upper ocean. The results show definite improvement in the sea surface temperature cooling, the upper-ocean thermal structure and mixed layer depths when the two schemes are adopted, because the upper-ocean vertical mixing processes are enhanced. The surface waves can especially strengthen the contribution of the vertical diffusion terms to the temperature cooling during the typhoon period.

Hydrocarbon condensation flow and heat transfer in wave helical pipes: Effect of structure parameters

In this study, two types of wave-structured pipes for heat exchangers that are easy to process are proposed, and the condensation pressure drop and heat transfer performances for hydrocarbon refrigerant upward flow in wave helical pipes are investigated. A numerical method based on the inhomogeneous two-fluid model is introduced and validated by experimental data in literature. The effect of wave parameters (wave height and wave length) on heat transfer, pressure drop and flow patterns are studied. At lower vapor quality conditions, it is found that as wave height increases, frictional pressure drop and heat transfer coefficient exhibit a trend of initially increasing, followed by decreasing, and then increasing again. However, under higher vapor quality conditions, frictional pressure drop and heat transfer coefficient continue to increase. Besides, both the frictional pressure drop and heat transfer coefficient increase with the decrease of wave length. The averaged enhancement on frictional pressure drop for vertical wave pipes and horizontal wave pipes are respectively 1.279–5.148 and 1.238–5.808 times, while the average augmentation in heat transfer coefficient is 1.243–3.006 and 1.316–3.579 times, respectively. The comprehensive thermal performance of wave pipes was assessed using the performance evaluation criterion. The range of averaged performance evaluation criteria (under different vapor qualities) in vertical wave pipes and horizontal wave pipes are respectively 1.150–1.737 and 1.230–2.026. The horizontal wave pipe when the wave height is 5 mm and wave length is 5.24 mm shows the best overall thermal performance, with an averaged performance evaluation criterion of 2.026. The two types of wave-structured pipes proposed in this paper can increase the pipe length of the spiral-wound heat exchanger at the same volume, while also improving the performance of the spiral-wound heat exchanger. The outcomes of the study can offer some assistance in creating simple but effective spiral wound heat exchangers.

The Generation of High-Energy Electron–Positron Pairs during the Breit–Wheeler Resonant Process in a Strong Field of an X-ray Electromagnetic Wave

The Breit–Wheeler resonant process was theoretically studied in a strong X-ray electromagnetic wave field under conditions when the energy of one of the initial high-energy gamma quanta passes into the energy of a positron or electron. These conditions were realized when the energy of a high-energy gamma quantum significantly exceeded the characteristic Breit–Wheeler energy, which was determined using the parameters of the electromagnetic wave and the initial setup. Analytical formulas for the resonant differential cross-section were obtained. It is shown that the resonant differential cross-section significantly depends on the ratio between the energies of the initial gamma quanta and the characteristic Breit–Wheeler energy. With a decrease in the characteristic Breit–Wheeler energy, the resonant cross-section increases sharply and may exceed the corresponding non-resonant cross-section by several orders of magnitude. The results make it possible to obtain narrow beams of ultrarelativistic positrons (electrons) with energies of the order ∼102 GeV and could also be used to explain high-energy fluxes of positrons (electrons) near neutron stars, as well as to simulate QED processes in laser fusion.

Wandering albatrosses exert high take-off effort only when both wind and waves are gentle

The relationship between the environment and marine animal small-scale behavior is not fully understood. This is largely due to the difficulty in obtaining environmental datasets with a high spatiotemporal precision. The problem is particularly pertinent in assessing the influence of environmental factors in rapid, high energy-consuming behavior such as seabird take-off. To fill the gaps in the existing environmental datasets, we employed novel techniques using animal-borne sensors with motion records to estimate wind and ocean wave parameters and evaluated their influence on wandering albatross take-off patterns. Measurements revealed that wind speed and wave heights experienced by wandering albatrosses during take-off ranged from 0.7 to 15.4 m/s and 1.6 to 6.4 m, respectively. The four indices measured (flapping number, frequency, sea surface running speed, and duration) also varied with the environmental conditions (e.g., flapping number varied from 0 to over 20). Importantly, take-off was easier under higher wave conditions than under lower wave conditions at a constant wind speed, and take-off effort increased only when both wind and waves were gentle. Our data suggest that both ocean waves and winds play important roles for albatross take-off and advances our current understanding of albatross flight mechanisms.

Wandering albatrosses exert high take-off effort only when both wind and waves are gentle.

The relationship between the environment and marine animal small-scale behavior is not fully understood. This is largely due to the difficulty in obtaining environmental datasets with a high spatiotemporal precision. The problem is particularly pertinent in assessing the influence of environmental factors in rapid, high energy-consuming behavior such as seabird take-off. To fill the gaps in the existing environmental datasets, we employed novel techniques using animal-borne sensors with motion records to estimate wind and ocean wave parameters and evaluated their influence on wandering albatross take-off patterns. Measurements revealed that wind speed and wave heights experienced by wandering albatrosses during take-off ranged from 0.7 to 15.4 m/s and 1.6 to 6.4 m, respectively. The four indices measured (flapping number, frequency, sea surface running speed, and duration) also varied with the environmental conditions (e.g., flapping number varied from 0 to over 20). Importantly, take-off was easier under higher wave conditions than under lower wave conditions at a constant wind speed, and take-off effort increased only when both wind and waves were gentle. Our data suggest that both ocean waves and winds play important roles for albatross take-off and advances our current understanding of albatross flight mechanisms.

Heterogeneity of the modified SIR-model parameters of waves of COVID-19 epidemic process in the Russian Federation

Introduction. The work is dedicated to the parameterization of the COVID-19 epidemic process, taking into account the specifics of the Russian Federation regions. 
 Purpose of study is the analysis of the spatio-temporal distribution of heterogeneous indicators of the spread of COVID-19 based on the formalization and parametrization of waves of the epidemic process, bearing in mind regional specifics.
 Materials and methods. SIR (+L) model as a modification of the classic SIR model, reflecting the trend in the transition of the susceptible to the action of the virus (S – susceptible) population to the group of infected (I – infected), recovered (R – recovered) and the dead (L – letal) was used as a basic model of the epidemic process.
 Results. Time ranges of activation of the epidemic process in the regions of the Russian Federation, corresponding to waves of domination of certain strains of the virus, have been allocated on the basis of the analysis of time series COVID-19 morbidity with a week period of averaging. In total, starting from September 6, 2020 and ending on February 25, 2023, four epidemic waves have been allocated for each region. Analysis of SIR (+L) model parameters for each wave by regions of the Russian Federation made it possible to establish a number of characteristic trends and obtain interpretable directions of influence on the epidemic process individual stages, with the subsequent development of systemic strategic decisions on the preservation of population health and its level of safety at the regional and country-wide scale.
 Limitations. The presented modification of the SIR model (SIR (+L) model) is a significant simplification of the real epidemic process and does not allow describing a number of observed effects.
 Conclusion. Based on the results of the parametrization of the epidemic process, the main features and patterns of the spread of the COVID-19, the intensity of recovery and mortality were established. A further direction of research may be the complication of the epidemic process model, the addition of new parameters to it, taking into account the division of the population into gender and age groups, diseases by severity, grouping according to the territorial and social principle, and the identification of the latent morbidity.

Bragg Scattering of Surface Gravity Waves by a Submerged Composite Wavy Porous Plate

Abstract Surface gravity wave interaction of composite wavy porous plate is studied by developing a numerical model using the boundary element method in the context of two-dimensional linear potential theory. Bragg scattering phenomenon is studied by considering the linearized pressure drop condition known as Darcy’s law passing through the porous structure. Numerical results are obtained through the boundary element method for the special limiting case of the existing previous literature to authenticate the accuracy of the numerical solution. The influence of wave and structural design parameters such as the number of ripple wavelengths of the wavy plate, relative plate length, structural porosities, and relative submergence depth on hydrodynamics properties such as reflection, transmission, horizontal wave load, and vertical wave coefficients are discussed. The study results of composite wavy porous plate indicate improved hydrodynamic performance as compared to the horizontal porous plate and wavy porous plate. This study is significant for practical applications in coastal engineering environments.

Data-driven localized waves and parameter discovery in the massive Thirring model via extended physics-informed neural networks with interface zones

In this paper, we study data-driven localized wave solutions and parameter discovery in the massive Thirring (MT) model via the deep learning in the framework of physics-informed neural networks (PINNs) algorithm. Abundant data-driven solutions including soliton of bright/dark type, breather and rogue wave are simulated accurately and analyzed contrastively with relative and absolute errors. For higher-order localized wave solutions, we employ the extended PINNs (XPINNs) with domain decomposition to capture the complete pictures of dynamic behaviors such as soliton collisions, breather oscillations and rogue-wave superposition. In particular, we modify the interface line in domain decomposition of XPINNs into a small interface zone and introduce the pseudo initial, residual and gradient conditions as interface conditions linked adjacently with individual neural networks. Then this modified approach is applied successfully to various solutions ranging from bright-bright soliton, dark-dark soliton, dark-antidark soliton, general breather, Kuznetsov-Ma breather and second-order rogue wave. Experimental results show that this improved version of XPINNs reduce the complexity of computation with faster convergence rate and keep the quality of learned solutions with smoother stitching performance as well. For the inverse problems, the unknown coefficient parameters of linear and nonlinear terms in the MT model are identified accurately with and without noise by using the classical PINNs algorithm.

Utility of ocean wave parameters for improving predictions of ambient noise

This study is concerned with prediction of the “wind noise” component of ambient noise (AN) in the ocean. It builds on the seminal paper by Felizardo and Melville (1995), in which the authors quantified the correlation between AN and individual wind/wave parameters. We utilize hydrophone observations deployed in the north and northeast Pacific Ocean. Wind/wave parameters are obtained from moored buoys and numerical models. We describe a procedure developed for this study which isolates the correlation of AN with wave parameters, independent of mutual correlation with wind speed (residual correlation). We then describe paired calibration/prediction experiments, whereby multiple wind/wave parameters are used simultaneously to estimate AN. We find that the improvement from inclusion of wave parameters is robust but modest. We interpret the latter outcome as suggesting that wave breaking responds to changes in local winds quickly, relative to, for example, total wave energy, which develops more slowly. This outcome is consistent with prior knowledge of the physics of wave breaking, e.g., Babanin (2011). We discuss this in context of the wave spectrum's time/space response to wind forcing.

Current Effect on Wave Condition around Island in the South China Sea

Abstract Currents have a significant impact on wave parameters around islands. In this study, high-resolution unsteady current simulations based on island geography and wind fields from Weather Research and Forecasting (WRF) Model are used as input sources. The wave action balance model uses an unstructured grid to assess the wave conditions in the Atoll during Typhoon Noul. The characteristic wave parameters, with and without the effect of currents, are compared with the field observation data, including significant wave height, wave period, and the spatial distribution of significant wave height. The results show that simulated significant wave heights and wave periods are close to observed data, considering the effect of currents. The energy and shape of the spectrum are also verified during Typhoon Noul, and the observed agreement is improved when considering the currents. The effects of current within the Atoll are relatively weaker compared to the surroundings, while stronger current effects are observed in the deeper water outside the Atoll. Refraction caused by current expands the area of moderate sea state behind the island. Significance Statement Several innovations of this article are as follows: 1) the influence of currents on wave conditions at the Atoll; 2) exploring the impact of currents using key parameters, such as significant wave height, wave period, and wave spectrum, especially during the passage of Typhoon Noul; 3) swell emerges as the dominant factor influencing wave conditions as the center of Typhoon Noul gradually moves away; and 4) refraction caused by current expands the area of moderate sea state behind the island.

Ocean ambient noise field modelling and the optimized noise term

The objective of this thesis is to determine the frequency and wind-wave forcing dependent effective sea surface noise source level per unit area extracted from the hourly minimum sound power levels of six month-long acoustic recordings. The effect of the propagation environment is accounted for using Bellhop. The simulated environment is configured using climatological sound velocity profiles to capture seasonal effects and bottom sound speed estimates made from seabed sediment maps. Hourly meteorological data were extracted from ERA5 providing relevant wind and wave parameters from which noise levels may be predicted. A weighted composite model consisting of neutral wind and significant wave height leveraging the two-term exponential regression function proved to maximize model R2. Received level data originating from 16 hydrophone stations in the North Atlantic and Labrador Sea were combined with the Bellhop TL simulations in order to produce estimates of the effective noise source level per unit area (NSL/A) for changing surface environmental conditions and inter-compared. Hourly minimum sound power level derived model-data comparisons using horizontal wind speed magnitude 10 m above sea level expressed a decrease in NSL/A estimates versus Kewley (1990) by 10 to 15 dB from 1 to 3 kHz.

Impact of Cortical Bone Thickness on the Parameters of Fast and Slow Ultrasound Wave based on 2-D Simulation

Quantitative Ultrasound (QUS) has been introduced to measure the quality of human bones using ultrasound and become one of the prevention methods for Osteoporosis diseases. Because of the porous composition inherent in human cancellous bone, the generation of both fast and slow waves occurs, and these waves exhibit a distinct association with the cancellous bone structure, particularly the extent of porosity. Nonetheless, the presence of these waves is also contingent upon the anisotropy of cancellous bone, and it is noteworthy that most human cancellous bones are enveloped by cortical bone, which may influence the parameters of the fast and slow waves. Therefore, the aim of this study is to perform a 2-Dimensional (2-D) simulation utilizing the through transmission (TT) measurement method. The primary focus is to examine the impact of cortical thickness on the parameters of both the fast and slow waves. The cortical thickness will be added to the cancellous bone models and the thickness will be varied. Then, the fast and slow wave parameters will be compared in terms of correlation coefficient to identify which wave is affected more. The result shows that the cortical thickness causes increasing in attenuation and velocity for both fast and slow waves. The increase in attenuation is due to sonometry effects while the different longitudinal velocities of water and bone material may contribute to the behaviors for phase velocity measurements. However, the fast wave shows more correlation with the cortical thickness for attenuation (R2 = 0.76) and phase velocity (R2 = 0.77) parameters. This is due to fast wave corresponding to the solid structure and increasing cortical thickness also increase the solid structure. Thus, analyzing fast waves against human cancellous bone, cortical bone thickness needs to be considered to ensure accurate measurements.

The Effect of an Exponentially Decaying Upper-Ocean Vertical Mixing on the Pacific Tropical Sea Surface Temperature

Abstract We investigate the mechanisms with which the sea surface temperature (SST) in the tropical Pacific responds to the perturbation of an exponential form to the background vertical mixing of the upper ocean. For a surface value of 0.005 m2 s−1 and a scale depth of 10 m (as typically used in the so-called nonbreaking wave parameterization), it is found that only ocean temperature within the equatorial eastern Pacific (EEP) is directly impacted; surface cooling and thermocline warming anomalies are produced. These signals propagate poleward as coastal Kelvin waves and then westward as equatorial Rossby waves. The surface cooling is severely damped while the thermocline warming is able to reach the western coast. This warm anomaly is brought up to the surface by equatorial upwelling more strongly around 110°W than at other places. In the coupled model, such equatorial warming induces an El Niño–like large-scale warming through Bjerknes feedback. Increasing the surface value of vertical mixing by a factor of 10 does not increase the equatorial surface warming while increasing the scale depth to 20 m does. Increasing the scale depth generates thermocline warming also in the subtropical region, which then propagates to the equatorial thermocline and enhances the warming there. Moreover, the off-equatorial cooling is enhanced, which makes the final warming anomaly narrower meridionally compared to an El Niño pattern.

Use of a rat model to characterize 35 arterial pulse wave parameters in a comparative study of isoflurane and Zoletil/xylazine anesthesia and the effect of Acanthopanax senticosus extract.

Information obtained from arterial pulse waveforms (APW) can be useful for characterizing the cardiovascular system. To achieve this, it is necessary to know the detailed characteristics of APWs in different states of an organism, which would allow APW parameters (APW-Ps) to be assigned to particular (patho)physiological conditions. Therefore, our work aimed to characterize 35 APW-Ps in rats under the influence of isoflurane (ISO) and Zoletil/xylazine (ZO/XY) anesthesia and to study the effect of root extract from Acanthopanax senticosus (ASRE) in these anesthetic conditions. The right jugular vein of anesthetized rats was cannulated for the administration of ASRE and the left carotid artery for the detection of APWs from which 35 APW-Ps were evaluated. We obtained data on 35 APW-Ps, which significantly depended on the anesthesia, and thus, they characterized the cardiovascular system under these two conditions. ASRE transiently modulated all 35 APW-Ps, including a transient decrease in systolic and diastolic blood pressure (BP) and heart rate or increases in pulse BP, dP/dtmax , and systolic and diastolic areas. Whereas the transient effects of ASRE were similar, the extract had prolonged disturbing effects on the cardiovascular system in rats under ZO/XY but not under ISO anesthesia. This negative effect can result from the disturbance caused by ZO/XY anesthesia on the cardiovascular system. We characterized 35 APW-Ps of rats under ISO and ZO/XY anesthesia and found that ASRE contains compounds that can modulate the properties of the cardiovascular system, which significantly depended on the status of the cardiovascular system. This should be considered when using ASRE as a nutritional supplement by individuals with cardiovascular problems.

Анализ параметров ударных волн на стенке взрывной полости при преломлении детонационных волн через воздушную и водную среду

Анализ параметров ударных волн на стенке взрывной полости при преломлении детонационных волн через воздушную и водную среду

Constraining a one-dimensional wave-type gravitational wave parameter through the shadow of M87* via Event Horizon Telescope

During the glorious success of the EHT in providing the first image of a black hole, numerous papers have been published about the effect of different astrophysical environments on black hole geometry. Motivated by the work on how gravitational wave affects the shadow of a Schwarzschild black hole [Eur. Phys. J. C 10.1140/epjc/s10052-021-09287-2], we extend it by considering a quantum correction on the black hole through the extended uncertainty principle (EUP). Along with this correction, we probe the gravitational wave’s effect on the null geodesics and photonsphere and find constraints to the gravitational wave parameter ϵ using the black hole shadow of M87* for some given test value for the gravitational wave frequency σ. Not only were some nodes found in the light trajectory, but the general behavior of paths changes periodically as the time t progresses. These patterns then confirm the chaotic formation of the shadow seen by some remote observer. Finally, the constraint that we find for ϵ is 10−10 orders of magnitude for the effect of the gravitational wave to be seen at a distance of D=16.8 Mpc. As a consequence of such a value for ϵ, another result reveals that while there is are gravitational wave effect on the shadow perceived at D, the deviations on the photonsphere are nearly non-existent. Apart from Earth-based detectors for gravitational waves, the study implies the possibility of an alternative detection method, especially if a gravitational wave source is near a lone black hole.

Predictive value of P wave parameters, indices, and a novel electrocardiographic marker for silent cerebral infarction and future cerebrovascular events

BackgroundSilent cerebral infarction (SCI) is a neuronal injury without a clinically apparent stroke or transient ischaemic attack. Left atrial cardiomyopathy is closely associated with SCI. P wave changes in the electrocardiogram (ECG) provide significant information about the development of atrial cardiomyopathy. This study evaluated the role of P wave parameters and indices and a novel ECG parameter in predicting SCI, future cerebrovascular events, and atrial fibrillation/flutter. Materials and methodsA total of 272 patients were retrospectively screened and divided into two groups according to SCI. Cerebrovascular events and atrial fibrillation/flutter were defined as the study's outcomes. P wave parameters, indices, and a novel ECG parameter called the P wave ratio (PWR) were calculated from ECGs, and the relationship between SCI and outcomes was investigated. ResultsThe maximum P wave duration (PWD), P wave dispersion (PWdisp), PWD measured from the D2 lead (PWDD2), P wave peak time measured from the D2 lead (PWPTD2), PWPT measured from the V1 lead (PWPTV1), and P wave terminal force (PWTFV1) were significantly longer in the SCI group. Both partial and advanced inter atrial block (IAB) were significantly high in the SCI group. The novel parameter P wave ratio (PWR) was significantly longer in the SCI group (0.55 ± 0.08 vs. 0.46 ± 0.09; p < 0.001). In multivariate regression analysis, PWdisp (OR: 1.101, p < 0.001), PWPTD2 (OR: 1.095, p = 0.017), and PWR (OR: 1.231, p < 0.001) were found to be independent predictors of SCI. Cox regression analysis revealed that the PWR (HR 1.077; 95% CI 1.029–1.128; p = 0.001) was associated with cerebrovascular events and atrial fibrillation/flutter. ConclusionIn our study, we observed that PWR could be a valuable parameter for predicting SCI and future cerebrovascular events.

Laboratory studies of the impact of non-breaking waves on a horizontal emerged deck

The horizontal elements of maritime structures are susceptible to both wave impact and resulting vibrations. These vibrations can lead to a partial or complete failure of structures and require detailed investigations. To address this issue, laboratory experiments were conducted in a wave flume. The aim of this study was to investigate the problem of standing wave impact underneath a horizontal deck. The main focus was on the effect of the wave-induced vertical forces on the global response of the structure. The physical model of the deck was installed above a still water level in front of a vertical barrier. The model was supported by a system of strings and springs. The mechanical system had one degree of freedom corresponding to a small rotational displacement around rear deck edge. Among other physical parameters, the impact pressure generated under the structure due to wave impact was measured. The high sampling frequency of the data acquisition system allowed to capture momentary slamming pressure. The systems of accelerometers and displacement gauges were installed to measure induced vibrations. Thorough analysis of the influence of wave parameters and the deck clearance on the structure response was performed based on the measurements. The rapid slamming force increase, recorded at the moment of impact is not revealed in the dynamic response of the plate.