Wave Reflection Characteristics Research Articles

Numerical Simulation of Hydrodynamic Performance of an Offshore Oscillating Water Column Wave Energy Converter Device

Wave energy, as a renewable energy source, plays a significant role in sustainable energy development. This study focuses on a dual-chamber offshore oscillating water column (OWC) wave energy device and performs numerical simulations to analyze the influence of chamber geometry on hydrodynamic characteristics and wave energy conversion efficiency. Unlike existing studies primarily focused on single-chamber configurations, the hydrodynamic characteristics of dual-chamber OWCs are relatively underexplored, especially regarding the impact of critical design parameters on performance. In this study, STAR-CCM+ V2302 software (Version 2410, Siemens Digital Industrial Software, Plano, TX, USA) is utilized to systematically evaluate the effects of key design parameters (including turbine configuration, mid-wall draught depth, and wall angles) on the hydrodynamic performance, wave energy capture efficiency, and wave reflection and loading characteristics of the device. The findings aim to provide a reference framework for the optimal design of dual-chamber OWC systems. The results show that the dual-chamber, dual-turbine (2C2T) configuration offers a 31.32% improvement in efficiency compared to the single-chamber, single-turbine (1C1T) configuration at low wave frequencies. In terms of reducing wave reflection and transmission, the 2C2T configuration outperforms the dual-chamber, single-turbine configuration. When the wall angle increases from 0° to 40°, the total efficiency increases by 166.37%, and the horizontal load decreases by 20.05%. Additionally, optimizing the mid-wall draught depth results in a 9.6% improvement in efficiency and a reduction of vertical load by 11.69%.

Unveiling heavy metal(loid) contamination and migration at an abandoned smelting site: Integrated geophysical and hydrological analyse

The heavy metal contamination at abandoned smelting sites is receiving increasing attention. This study focuses on an abandoned lead–zinc smelting site and uses several methods (such as soil sampling, geophysical exploration, and groundwater monitoring) to systematically investigate the contamination characteristics, distribution patterns, and migration mechanisms of heavy metal(loid) in soil and groundwater. A geological structure model of the study area was established through drilling data and geophysical techniques (Ground penetrating radar (GPR) and Electrical resistivity tomography (ERT)), revealing the relationships among soil resistivity, electromagnetic wave reflection characteristics, and geological structure. This study revealed that heavy metal contamination in soil was concentrated mainly northwest of the site and was closely related to historical smelting activities. The presence of heavy metal(loid)s in groundwater had a complex correlation with soil physicochemical properties and environmental elements, and its distribution was influenced by both hydrogeological conditions and soil properties. This study also investigated the effects of the soil water content (SWC) and soil hydraulic conductivity (Ks) on heavy metal(loid)s migration and reported that high SWC and Ks contribute to the dissolution and migration of heavy metals. In addition, a 3D visualization model of heavy metal contamination plumes was established via Voxler software. This model intuitively demonstrated the migration and diffusion of heavy metal(loid)s in the underground environment, offering a novel perspective on their subsurface behavior. The research results provide important information for understanding the migration of heavy metal(loid)s in soil-groundwater systems.

Central and peripheral cardiovascular responses after acute dietary nitrate supplementation in post-menopausal women

The transition to menopause is accompanied by augmented cardiovascular disease risk, partially attributed to reduced nitric oxide (NO) bioavailability. Despite a lower arterial stiffness than men, postmenopausal women are susceptible to increased aortic pulsatile hemodynamic load because of greater pressure wave reflection and vascular dysfunction. Increasing bioavailable NO with dietary nitrate has shown promise to reduce aortic (aSBP) and brachial (bSBP) systolic pressure healthy postmenopausal women. However, there are limited reports comparing hypertensive (HTN) and normotensive (NTN) postmenopausal women regarding wave separation analysis and vascular function following dietary nitrate supplementation. This study investigated if acute dietary nitrate supplementation would improve aortic hemodynamics, wave reflection characteristics, vascular stiffness, and vasodilatory function. We hypothesized that dietary nitrate would lower pulse wave velocity in hypertensives, lower aortic and brachial blood pressures and forward and backward wave magnitude and increase microvascular, but not macrovascular function in both groups. Fourteen postmenopausal women (n=7 HTN; n=7 NTN) participated in a two-day randomized crossover study design with dietary nitrate (nitrate rich, NR) or a placebo control (NP). Central and peripheral hemodynamics and carotid-femoral pulse wave velocity (cfPWV) were performed with a SphygmoCOR Excel, simultaneous resting macro- and- microvascular function was assessed using flow-mediated vasodilation (FMD) and post occlusive reactive hyperemia (PORH) using near-infrared spectroscopy. aSBP was reduced significantly following NR supplement within groups (HTN: NP 126±2 NR 120±1mmHg) and NTN group (NP 110± 1 NR 104±3mmHg p<0.05). Forward pulse height HTN (NP 29±1.4 NR 26.3±1.4mmHg) NTN (NP 25.6±0.9 NR 24±2.7mmHg) and reflected pulse height HTN (NP 18.2±0.08 NR 17.2±0.4mmHg) NTN (NP 17.7±0.2 NR 15.7±1.07mmHg) were not different. cfPWV was faster in the HTN group and slowed with a NR supplement (HTN: NP 8.2±0.29 NR 7.4±0.31m/s; NTN NP 7.1±0.23 NR 6.6±0.62m/s p<0.05). A significant interaction for %FMD was found (HTN: NP 7.3±0.8 NR 6.2±0.8%; NTN NP 6.6±0.7 NR 9.4±0.7%). Further, we found no difference in the NIRS derived microvascular function measurements (HTN: NP 1.9±0.2 NR 1.7±0.3%/s; NTN NP 1.6±0.1 NR 1.4±0.2%/s p>0.05). These data indicate that dietary nitrate consumption led to a substantial reduction in aortic hemodynamics and reduced pulse wave velocity regardless of hypertension status. Interestingly, macrovascular, but not microvascular vasodilatory function was improved in the NTN women only. Dietary nitrate supplementation appears to have differential effects when considering HTN and NTN postmenopausal women. Supported with funds from The University of Wisconsin-La Crosse RSEL graduate grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A novel approach for generalized Green-Naghdi-type electro-magneto-thermo-hyperelasticity wave propagation and reflection investigations in near-incompressible layers under shock loads

A novel nonlinear coupled finite-strain electro-magneto-thermo-hyperelasticity (EMTHE) model is developed for the first- and second-sound wave propagation and reflection investigations in media that are exposed to electromagnetic fields and mechanical shocks. In contrast to the previous studies which studied behaviors of the finite-strain elastic or incompressible materials with small deformations, the current research proposes a much more complicated but much more accurate novel practical model for wave propagation and reflection analyses in near-incompressible finite-strain materials. Furthermore, to evaluate the effects of the electro-magneto-thermomechanical coupling, the strain energy density function of the hyperelastic material is expanded in a new way. The governing equations are obtained according to a nonlinear version of the Helmholtz free energy. The energy equations comprise the first- and second-order time rates of the temperature to enable the modeling of the finite-speed heat transfer; i.e., the establishment of a second-sound model. A nonlinear iterative finite element solution algorithm is proposed and implemented for the resulting coupled time-dependent generalized electro-magneto-thermo-hyperelasticity equations. The results show significant differences between the predicted wave propagation and reflection characteristics and behaviors of the near-incompressible and incompressible finite-strain models.

Experimental investigation on the hydrodynamic performance of an inverted trapezoidal breakwater

ABSTRACT The wave transmission, reflection, and dissipation characteristics of conventional (trapezoidal (TBs)) and non-conventional (inverted trapezoidal (ITBs) and rectangular (RB)) breakwaters with the same volume and porosity are evaluated under different submergence ratios, wave heights, and wave periods in regular and random waves. The experimental investigation revealed that the ITB shape is the most efficient cross section for reducing wave transmission coefficient (Kt) when the breakwater is submerged or the still water level (SWL) is at the crest of the breakwater, whereas the conventional TB is the least efficient. Compared to the conventional TB, the ITB reduced Kt by 10%–20% under submerged conditions and by 20%–30% when the SWL is at the breakwater crest. Kt < 0.2 is obtained for a relative water depth d/Lp > 0.2, which is suitable for most wave damping applications in the field when the ITB crest is at the SWL or when the crest emerges.

The Effects of Target Thicknesses and Backing Materials on a Ti-Cu Collision Weld Interface Using Laser Impact Welding

This study demonstrates that the thickness of the target and its backing condition have a powerful effect on the development of a wave structure in impact welds. Conventional theories and experiments related to impact welds show that the impact angle and speed of the flyer have a controlling influence on the development of wave structure and jetting. These results imply that control of reflected stress waves can be effectively used to optimize welding conditions and expand the range of acceptable collision angle and speed for good welding. Impact welding and laser impact welding are a class of processes that can create solid-state welds, permitting the formation of strong and tough welds without the creation of significant heat affected zones, and can avoid the gross formation of intermetallic in dissimilar metal pairs. This study examined small-scale impact using a consistent launch condition for a 127 µm commercially pure titanium flyer impacted against commercially pure copper target with thicknesses between 127 µm and 1000 µm. Steel and acrylic backing layers were placed behind the target to change wave reflection characteristics. The launch conditions produced normal collision at about 900 m/s at the weld center, with decreasing impact speed and increasing angle moving toward the outer perimeter. The target thickness had a large effect on wave morphology, with the wave amplitude increasing with target thickness in both cases, peaking when target thickness is about twice flyer thickness, and then falling. The acrylic backing showed a consistently smaller unwelded central zone, indicating that impact welding is possible at a smaller angle in that case. Strength was measured in destructive tensile testing. Failure was controlled by the breakdown of the weaker of the two base metals over all thicknesses and backings. This demonstrates that laser impact welding is a robust method for joining dissimilar metals over a range of thicknesses.

Roles of breaking and reflection in wave energy attenuation on the shoreface-nourished beach

Shoreface nourishments with the artificial sandbar are effective strategies to mitigate coastal erosions mainly by wave breaking and reflection. Thus, a better understanding of the contributions of breaking and reflection in wave energy loss is important for the prediction and description of the performance of the shoreface nourishment. Experiments are conducted in a wave flume, and data analysis is complemented with numerical simulations performed with a phase-resolving model. Both incident and reflected wave heights are well reproduced by the numerical model. The ratio of reflection to reflection-plus-breaking energy loss ranges from 4% to 11%, implying the dominant role of breaking-induced dissipation over reflection in present cases. The wave transmission coefficient decreases with the decrease in the bar crest depth and onshore implementation of the artificial sandbar. The trapezoidal artificial sandbar promotes an intense wave breaking over the berm width and is more effective in eliminating waves than the triangular artificial sandbar. Due to the erodible nature of the artificial sandbar, future works will consider the use of a hydro-morphological coupled approach to study the time-varying characteristics of wave breaking and reflection during morphological evolution.

Correlation between pulse wave analysis parameters and left atrial strain and left ventricular myocardial work indices in patients with grade one hypertension

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Central arterial blood pressure and wave reflection characteristics are independent predictors of cardiovascular morbidity and mortality. Pulse wave analysis (PWA) can non-invasively assess these central hemodynamic indices, by deriving central aortic waveform from brachial waveform, and allowing evaluation of central systolic pressure (CSP), Pulse Pressure (PP), augmentation pressure (AP) and augmentation index (AIx), defined as the ratio of AP to central pulse pressure (PP). These parameters are thought to relate to reflected pressure waves. Purpose To investigate whether central hemodynamic indices can impact on left atrial (LA) and left ventricular (LV) performance in patients with grade one hypertension. Materials and Methods 80 pts (male 39; mean age 41 ± 13 years) were prospectively enrolled, distinguishing between not-hypertensives(n=40; male 21; mean age 39 ± 10 years)and newly diagnosed grade one hypertensives(n=40; male 18; mean age 42 ± 11 years), not yet under treatment. All underwent PWA measurement through a standard brachial cuff for measuring CSP (mmHg), PP (mmHg), AP (mmHg), Aix (%) and augmentation index normalized to 75 bpm heart rate (AIx75%). At the same time a complete transthoracic echocardiogram was performed, and LA strain and LV myocardial work parameters were calculated. Results Hypertensives have higher LV mass index(73±16 vs 70±24;p = 0,4) but without any significant difference. On the other hand, hypertensives have significantly higher values of LA volume index (LAVi) (25±6 vs 19±7 ml/mq;p = 0,02). LV global longitudinal strain (GLS) values (−19,4±2 vs −20,3±1,7 %;p = 0,1) don't statistically differ between the two groups. Global work efficiency (GWE) is reduced in Hypertensives than in controls (94±2 vs 96±1,2 %;p = 0,003), while Global wasted work (GWW) is higher in Hypertensives than in controls (146±75 vs 85±27 mmHg%; p = 0,02). Higher values of LAVi are associated with higher values of CSP (r=0,4;p&amp;lt;0,0001), PP (r=0,3;p = 0,01), AP (r=0,4;p&amp;lt;0,0001); Aix (r=0,3;p&amp;lt;0,0001) and Aix75% (r=0,3;p = 0,01). LA reservoir inversely correlates to AP (r=-0,3;p = 0,01), Aix (r=-0,3;p = 0,01) and Aix75% (r=-0,3;p = 0,02). LV mass index directly correlates with PP (r=0,3;p = 0,01), Aix (r=0,3; p = 0,001), AIx75% (r=0,3; p = 0,01) and AP (r=0,4; p&amp;lt;0,0001). Central systolic pressure directly correlates with GLS (r=0,3; p = 0,001) and GWW (r=0,5;p&amp;lt;0,0001) and inversely correlates with GWE (r=-0,5;p&amp;lt;0,0001). Higher values of augmentation pressure are associated with lower values of GWE (r=-0,3;p = 0,01). Higher diastolic dysfunction degrees are associated with higher values of CSP (r=0,5;p&amp;lt;0,0001), PP (r=0,5; p&amp;lt;0,0001), AP (r=0,4;p = 0,0001); Aix (r=0,3; p = 0,002) and Aix75%(r=0,4; p&amp;lt;0,0001). Conclusions: Higher central pressure and reflected pressure waves can impact on LA and LV function leading to an early damage that can be correctly identified by an integrated approach between PWA and Advanced Echocardiography.

Polarity of current area based active injection protection scheme for hybrid MMC-HVDC grids

With the massive increase of power electronic devices to facilitate renewable integration, the system’s fault characteristics will be dramatically changed due to the different control strategies adopted by converters. As a result, the dependability and security of the traditional protection can be severely compromised. Considering the high controllability of power electronic converters, this paper presents an active injection protection scheme to effectively identify the fault. By analyzing the traveling wave (TW) refraction and reflection characteristics under different fault conditions, the variation of the measured terminal current caused by the TW is revealed. Then, a rectangular wave is injected by the hybrid modular multilevel converters (MMC) for a short time after the fault ride-through process. By introducing the concept of the polarity of the current area, the proposed protection scheme only needs to measure the terminal current without any complex signal extracting and processing algorithm to identify the internal and external faults. The feasibility and effectiveness of the proposed protection scheme are verified by realistic case studies with simulation conducted in the PSCAD platform.

A Novel Approach for Radar Passive Jamming Based on Multiphase Coding Rapid Modulation

Electromagnetic controlled surface (ECS) which can regulate the amplitude and phase of electromagnetic wave reflection characteristics has attracted extensive attention in recent years because of its radar stealth effect by reducing the radar cross section (RCS). However, radar detection cannot be avoided only by stealth in the energy field gradually. It is a novel pulse Doppler radar jamming mode proposed in this paper to utilize the self-correlation of radar-transmitted waveforms to result in signal processing and radar detection failure through the rapid time-domain variation of phase coding ECS. In principle, phase modulation alters the intra-pulse characteristics of the original signal and fundamentally interferes with the processing of the radar signal. In this paper, random and periodic phase coding sequences are proposed according to different forms of radar jamming. And through the derivation formula and simulation experiment, the jamming effect under multi-phase modulation is verified. Among them, the target energy is dispersed to the surroundings to form a wide envelope through random coding modulation, which leads to noise barrage jamming. While we use periodic sequence coding modulation, the target is shifted in the range-Doppler domain, causing misplaced coherence on the radar echo and deceptive jamming to the radar. Moreover, the technology can also be widely used in synthetic aperture radar (SAR) imaging, microwave measurement and other remote sensing fields. To further confirm the accuracy and efficiency of the proposed method, multi-parameter contrast experiments and parameter sensitivity analyses are conducted.

Hydrodynamic performances of a wall type breakwater - a physical and numerical approach

In this paper, hydrodynamic characteristics of caisson type breakwater are investigated through physical model approach and a numerical model based on the Volume of Fluid (VOF) is validated. The investigations are carried out for varying wave characteristics and depth of water 0.50 m. In an experimental study, to understand the model and scale effects for the desired wave conditions is a critical task in all-time conditions. So, it is also necessary to develop an appropriate numerical model to understand the hydrodynamics of the selected test model. Using the Volume of Fluid (VOF) method and incompressible open channel fluid flow a 2D numerical wave flume is developed using ANSYS- Fluent platform. The wave boundary conditions are adopted by solving the Reynolds-Averaged Navier Stokes equations (RANS equation) and especially with k—ε model to examine the effects of turbulence on the numerical results. The wave forces, wave runup, and wave reflection characteristics on the test model are measured for different wave characteristics, and results obtained from the numerical investigations are comparable with the experimental results to evident the relevance of the developed numerical model.

Hydraulic performance of perforated enlarged pile head breakwaters through laboratory investigation

An economical, ecofriendly and efficient breakwater system is vital for coastal protection and harbour tranquility. In this regard, various researchers are working to develop the appropriate solutions to encounter site-specific challenges. With this viewpoint, concept of enlarged pile head breakwater is developed. The study focuses on improving the hydraulic efficiency of pile breakwater by enlarging the structure near the free surface and providing it with perforations. Effect of percentage distribution of perforations, size of perforations and percentage of perforations on wave transmission, reflection and dissipation characteristics of the structure is investigated. The physical experiments are conducted in a two-dimensional wave flume under varying monochromatic wave climates. Results indicate that the pore size highly dominants the wave attenuation than considering the increasing percentage of perforations with the small size of the pore. Perforations effectively reduce the Kt of about 10%–18% to that of non-perforated pile head breakwater. Hydraulic efficiency of enlarged pile head breakwater is optimum when D/Hmax = 0.6, Y/Hmax = 1.0, b/D = 0.2, S = 0.25D, pa = 75% and P = 22.5 at 0.3 m water depth. A hybrid theoretical solution is developed based on the current set of experimental data for the quick estimate of hydraulic coefficients. The proposed hybrid equation for the perforated pile breakwater predicts more desirable values of Kt, Kr and Kd. The proposed concept of breakwater gives a reasonably enhanced hydraulic efficiency than the compared type of breakwaters.

High-Precision Forward Analysis and Field Test of Boulder Detection on Zero-Offset Elastic Wave Method in Shield Tunnel

Efficient and accurate boulder detection technology is essential for shield tunneling safely under complex floodplain geological conditions. The traditional seismic reflection method is not suitable for complex geological conditions and small targets near the surface, the elastic wave reflection method based on zero-offset observation is proposed in this article. Forward is the basis of inversion, a high-order staggered grid finite difference algorithm based on least-squares optimization (LS-SGFD) is established, which has the advantages of higher accuracy and smaller dispersion. Three typical geological models are designed, and the elastic wave reflection characteristics of the method proposed in this paper and the traditional method are systematically analyzed. From the dual perspectives of field experiment and engineering application, the effectiveness of zero-offset observation for the detection of boulders is discussed, and the basic criteria for boulder identification are given. Research shows that this method has good results in detecting boulders on the surface, and it has certain reference significance for similar projects.

Wave–current-surge interaction in a changing climate over a shallow continental shelf region

Wave climate over the North Indian Ocean region experienced a paradigm shift in the recent past, indicating an increase in the extremes. Wind-waves and swell climatology have shown an increasing trend over this region, having direct implications on the coastal zone dynamics surrounding the mainland and island features. The present study aims to investigate the wave–current-surge interaction characteristics over a shallow continental shelf region between India and Sri Lanka using the state-of-art coupled ADCIRC-SWAN model. In particular, a case study performed during tropical cyclone Madi (2013) demonstrates the extreme wave–current-surge interaction mechanism over varying nearshore bathymetric features. Study investigated the wave reflection and transmission characteristics in both the absence and presence of the proposed navigation channel (known as Sethusamudram project) in a coastal vulnerability context. Construction of the channel may result in westward shift of hazardous coastal water zones attributed to storm tides. The navigation channel expects to enhance both extreme waves and storm surge by 1% and 4%, respectively. Synthetic experiments, considering an increase in sea level rise by 0.4 m expected by 2050, indicate that wave activity can increase by 3% with marginal variations in storm tide. Simulations performed with a 7% rise in tropical cyclone intensity reveals a substantial increase in storm surge (10%) and significant wave (20%) heights along the coastal belt.

Modeling studies on the behavior of single and double rubble mound breakwaters using genetic programming tool

Experimental investigation on wave transmission, reflection and dissipation characteristics of rubble mound breakwater models are time consuming and expensive. However, such studies are required for designing the rubble mound breakwaters for marine structures in an optimal condition. In order to overcome such problems many researchers used various soft computing techniques such as Artificial Neural Network (ANN), Adaptive Neuro Fuzzy Interference System (ANFIS), Genetic Programming (GP), Support Vector Machine (SVM) etc, in order to predict the design factors in the field of coastal engineering. The current work proposes Genetic Programming (GP) as a modeling tool to evolve mathematical models for the behavior of single and double breakwaters. Based on the detailed experimental data, GP models were performed to predict the reflected wave height (H r ), wave height on the breakwater (H 5 ) and transmitted wave height (H t ) by considering with and without trigonometric effects of those breakwaters. The quality of predictability of the present model is measured by the statistical parameter, RMSE (Root Mean Square Error). Since the waves were more complex in nature, it is very essential in considering the trigonometric function’s effect in the modeling aspects. It is evident that, the GP model accurately described the non linear complex effects.

Surrogate-Assisted Design of Checkerboard Metasurface for Broadband Radar Cross-Section Reduction

Metasurfaces have been extensively exploited in stealth applications to reduce radar cross section (RCS). They rely on the manipulation of backward scattering of electromagnetic (EM) waves into various oblique angles. However, arbitrary control of the scattering properties poses a significant challenge as a design task. Yet it is a principal requirement for making RCS reduction possible. This article introduces a surrogate-based approach for rapid design optimization of checkerboard metasurfaces. Our methodology involves fast metamodels, and a combination of surrogate-assisted global optimization with local, gradient-based tuning. It permits an efficient control of the EM wave reflection characteristics, and ensures arriving at that the globally optimum solution within the assumed parameter space. The design procedure is fully automated. The framework is employed to develop a novel broadband checkerboard metasurface, where the RCS reduction is fundamentally based on the backward scattering manipulation carefully controlled by simultaneous adjustment of the unit cell dimensions. The properties of the structure are demonstrated using simulated monostatic and bistatic RCSs. The proposed metasurface exhibits 6 dB RCS reduction within the frequency range from 16 to 37 GHz. The numerical results are validated using physical measurements of the fabricated prototype. Experimental data indicates that the relative RCS reduction bandwidth is 83 percent, which makes the proposed structure outperforming the designs reported in the literature.

Wave reflection characteristics at the pile tip-soil interface under low strain dynamic condition

The wave reflection characteristics of the pile tip-soil interface under the low-strain condition were studied for exploring the possible quantitative method of detecting and judging the support conditions of the pile base. Based on the one-dimensional wave theory, a new theoretical method was proposed for studying the relation between the upward stress wave (UW) and downward stress wave (DW) under different support stiffness (k′) of the base soil. The frequency response functions (FRFs) of the displacement, velocity, and axial force were derived, simulating the soil resistance with the viscoelastic model. When the downward velocity (vd) was a semi-sinusoidal function, the upward velocity (vu) under different support stiffness was calculated. It was shown that the FRFs reflects the reflection characteristics in the frequency domain. The FRF of velocity is the same as FRF of displacement but opposite to that of force. The relation between vu/vd and k′ is antisymmetric about the horizontal axis of logarithmic coordinate, and vu/vd decreases from 1 to −1 as k′ increases from 0 to +∞. The model experiment verified the theoretical calculation results. This research is useful for the theoretical study of the reflection characteristics at the pile tip and engineering applications.

Hydroelastic response of floating elastic plate in the presence of vertical porous barriers

ABSTRACT The attenuation of the incident wave interacting with a very large floating structure (VLFS) in the presence of vertical barriers is analysed considering small amplitude wave theory. The VLFS is considered to be articulated and is modelled based on Timoshenko-Mindlin plate theory. The eigenfunction expansion method along with the orthogonal mode-coupling relation is employed for the case of finite water depth. The numerical study is performed to analyse the wave reflection, transmission and dissipation characteristics due to the articulated floating plate for the case of bottom standing and surface piercing vertical porous barriers. The hydroelastic behaviour in terms of deflection and strain for an articulated floating thick elastic plate in the presence of porous barriers is analysed. The study reveals that the magnitude of wave attenuation is enhanced due to the presence of vertical porous barriers and also provides an understanding in mitigating the structural response.

Sympathetic neural modulation of arterial stiffness in humans.

Elevated large-artery stiffness is recognized as an independent predictor of cardiovascular and all-cause mortality. The mechanisms responsible for such stiffening are incompletely understood. Several recent cross-sectional and acute experimental studies have examined whether sympathetic outflow, quantified by microneurographic measures of muscle sympathetic nerve activity (MSNA), can modulate large-artery stiffness in humans. A major methodological challenge of this research has been the capacity to evaluate the independent neural contribution without influencing the dynamic blood pressure dependence of arterial stiffness. The focus of this review is to summarize the evidence examining 1) the relationship between resting MSNA and large-artery stiffness, as determined by carotid-femoral pulse wave velocity or pulse wave reflection characteristics (i.e., augmentation index) in men and women; 2) the effects of acute sympathoexcitatory or sympathoinhibitory maneuvers on carotid-femoral pulse wave velocity and augmentation index; and 3) the influence of sustained increases or decreases in sympathetic neurotransmitter release or circulating catecholamines on large-artery stiffness. The present results highlight the growing evidence that the sympathetic nervous system is capable of modulating arterial stiffness independent of prevailing hemodynamics and vasomotor tone.

Simultaneous estimation of adherend and adhesive thickness, and interfacial stiffness for adhesive joints based on elastic wave reflection and propagation characteristics

Simultaneous estimation of adherend and adhesive thickness, and interfacial stiffness for adhesive joints based on elastic wave reflection and propagation characteristics