Angle Anisotropy Research Articles

Loading rates dependency of strength anisotropy in coal: Based on the three‐dimensional reconstruction modeling technology

AbstractWe explored the dependency of strength anisotropy on loading rate in coal both experimentally and numerically. An improved numerical modeling method was developed for this investigation to reduce the random error caused by the mechanical differences of coal specimens. After that, specimens with different anisotropy angles (the angle between the coring direction and bedding plane orientation) were processed (0°, 15°, 30°, 45°, 60°, and 90°). These specimens were then scanned by the X‐ray Computed Tomography (CT) and tested by unconfined loading frame. Uniaxial compressive simulations were performed on 15 numerical models with different anisotropy angles at various loading rates (1.0 × 10−6, 5.0 × 10−6, 10.0 × 10−6, and 20.0 × 10−6 mm/step). The results indicate that the uniaxial compressive strength (UCS) of coal generally first decreases and then increases as the anisotropy angle increases from 0° to 90° for all loading rates. It is also found that the UCS increases significantly with the increasing loading rate at anisotropic angles of 30° and 45°, while it is less obvious at anisotropic angles of 0° and 90°. This results in a reduced USC anisotropy at high loading rates. Meanwhile, a negative exponential equation is obtained to describe the variation of UCS with the loading rate at different anisotropic angles. And a unified equation is then developed and verified to define the UCS as a function of the loading rate and anisotropic angle.

Current-Induced Magnetization Switching of Exchange-Biased NiO Heterostructures Characterized by Spin-Orbit Torque

In this work, we study magnetization switching induced by spin-orbit torque in W(Pt)/Co/NiO heterostructures with variable thickness of heavy-metal layers W and Pt, perpendicularly magnetized Co layer and an antiferromagnetic NiO layer. Using current-driven switching, magnetoresistance and anomalous Hall effect measurements, perpendicular and in-plane exchange bias field were determined. Several Hall-bar devices possessing in-plane exchange bias from both systems were selected and analyzed in relation to our analytical switching model of critical current density as a function of Pt and W thickness, resulting in estimation of effective spin Hall angle and perpendicular effective magnetic anisotropy. We demonstrate in both the Pt/Co/NiO and the W/Co/NiO systems the deterministic Co magnetization switching without external magnetic field which was replaced by in-plane exchange bias field. Moreover, we show that due to a higher effective spin Hall angle in W than in Pt-systems the relative difference between the resistance states in the magnetization current switching to difference between the resistance states in magnetic field switching determined by anomalous Hall effect ($\Delta R/\Delta R_{\text{AHE}}$) is about twice higher in W than Pt, while critical switching current density in W is one order lower than in Pt-devices. The current switching stability and training process is discussed in detail.

Anisotropic Behavior of Cohesive Soils by Considering Effect of Gradation and Plasticity Characteristics

In practice, strength of soils commonly is measured isotropically, while for accurate design of structure foundations and earth structures, it is essential to consider the effect of anisotropy phenomenon on the mechanical behavior of the soils. In previous research, the effect of anisotropy on shear strength of sandy soils has been known and there is some limited work on cohesive soil. Moreover, anisotropy impact is not known on shear-induced pore water pressure. In this research, a series of triaxial tests were carried out on the undisturbed samples of different fine-grained soils, taken at different directions in the sites. The samples were consolidated under effective isotropic stresses of 200, 300, 500 and 700 kPa, and loaded in undrained condition. The results revealed that the behavior of all soils significantly depends on the sample orientation in the field. As the direction of samples changed from “perpendicular to bedding orientation” to “parallel to bedding orientation”, the shear strength decreased gradually and it has the minimum value at anisotropy angle of 72°, 59° and 90° for red clay, yellow marl and olive marl, respectively. The reduction rate completely depends on the soil plasticity and level of confining pressure.

Molecular dynamics simulation of octacosane for phase diagrams and properties via the united-atom scheme.

We used the united-atom scheme to build three types of crystalline structures for octacosane (C28H58) and carried out molecular dynamics simulations to investigate their phase properties. By gradually heating the three polymorphs, we managed to reproduce the sequence of experimentally reported crystalline phases and rotator phases. By studying the system density, molecule morphology, chain tilt angle and cell anisotropy, we hypothesized three mechanisms behind the observed system deformations and phase transformations during the annealing process. Furthermore, our model successfully predicted the melting temperature and heat of fusion. We also reproduced the characteristics of the rotator phases and the liquid phase, validating the transferability of the united-atom scheme among the different condensed phases of octacosane. Our methodology represents an effective and efficient means of numerical study for octacosane and may be used for other members of the n-alkane family.

Attention Span Prediction Using Head-Pose Estimation With Deep Neural Networks

Automated human pose estimation is evolving as an exciting research area in human activity detection. It includes sophisticated applications such as malpractice detection in the examination, distracted driving, gesture detection, etc., and requires robust and reliable pose estimation techniques. These applications help to map the attention of the user with head pose estimation (HPE) metrics supported by emotion and gaze analysis. This paper solves the problem of attention score estimation with HPE. The proposed method ensures ease of implementation while addressing head pose estimation using 68 facial features. Further, to attain reliability and precision, head pose estimation has been implemented as a regression task. The coordinate pair angle method (CPAM) with deep neural network (DNN) regression and elastic net regression is carried out. The use of DNN ensures precision on low lighting, distorted or occluded images. CPAM methodology leverages facial landmark detection and angular difference to estimate head pose. Experimentation results showed that the proposed model could handle large datasets, real-time data processing, significant pose variations, partial occlusions, and diverse facial expressions with a mean absolute error (MAE) of 3° and less. The proposed system was evaluated on three standard databases: the 300W across large poses (300W-LP) dataset, annotated facial landmarks in the wild (AFLW2000) dataset, and the national institute of mental health child emotional faces picture set (NIMH - ChEFS ) dataset. The results achieved are on par with recent state-of-the-art methodologies such as anisotropic angle distribution learning (AADL), joint head pose estimation and face alignment algorithm (JFA), rotation axis focused attention network (RAFA-Net), and propose an MAE ranging up to 6°. The paper could achieve remarkable results for attention span prediction using head pose estimation and for many possible future applications.

Investigation of the Kaiser effect in anisotropic rocks with different angles by acoustic emission method

The utilize of Kaiser effect during acoustic emission testing is a novel approach for computing the amount of stress in the rock, which has been tremendously exploited due to the immense reduction in the cost and time of determining the in-situ stress. Several parameters influence the accuracy of the Kaiser effect. This paper investigates the effect of anisotropy on the Kaiser effect on the rock. For this purpose, acoustic emission effect in the uniaxial compression test and Brazilian tensile strength test on the Phyllites specimens with various angles of anisotropy (0, 30, 60, and 90°) has been conducted. The results demonstrate that in all uniaxial compression tests, the Felicity ratio of acoustic emission, which is defined as the ratio of the stress at which the Felicity effect occurs to the previously applied maximum stress, is close to one. In other words, the anisotropy does not have a significant effect on the values of the Felicity ratio. In Brazilian tensile strength tests, only the sample with zero-degree angle of anisotropy has a Felicity close to one, which means that the Kaiser effect in this condition is predicted more accurately. In addition, the results show that the uniaxial compression tests are more accurate in determining the Kaiser effect than Brazilian tensile strength tests.

The effects on CMB power spectra and bispectra from the polarization rotation and its correlations with temperature and E-polarization

The Chern-Simons term, through which the cosmic Axion-like field couples to the electromagnetic field, has the effect to rotate CMB polarization directions and to break the CPT symmetry. This rotation will change the CMB power spectra, no matter isotropic or anisotropic the rotation angle is. In this paper we revisit this issue by further considering the correlations between the anisotropic rotation angle α and the CMB temperature and CMB E polarization fields. These correlations could be generated in the Axion-like models with nonzero potential under the adiabatic initial condition. We first investigate how these correlations contribute further modifications to the CMB power spectra, then calculate the CMB bispectra for the temperature and rotated polarization fields. These bispectra would vanish if the Tα and Eα correlations are absent. So, they are useful in searching for CPT violation and the Tα and Eα correlations arisen in the Axion-like models.

Reflection Angle-Domain Pseudoextended Least-Squares Reverse Time Migration Using Hybrid Regularization

Angle-domain common image gathers (ADCIGs) describe the reflectivity variation over reflection angles which are important for seismic exploration. The ADCIGs could be obtained using reverse time migration (RTM). However, because of the limitation of seismic frequency band and acquisition geometry, RTM produces the ADCIGs with low fidelity. We propose a reflection angle-domain pseudoextended least-squares RTM method to improve the quality of the ADCIGs in which the Poynting vector is used to efficiently calculate the angles. We first extend the inverted model in the reflection angle domain and derive a feasible pseudoextended Born modeling operator which can map the reflection angle-domain extended model to seismic data. The modeling operator, associated with an adjoint operator, are then used to build a pseudoextended linearized inversion framework for inverting the angle-dependent reflectivity. Taking advantage of the simplicity and coherency of the ADCIGs, we impose a series of low-rank constraints on the extended angle dimension and a sparse constraint on the whole dimension to ensure the production of high-quality ADCIGs. The proposed method is finally solved by a regularized conjugate gradient algorithm. We conduct several numerical examples on a flat layer model, the Marmousi model, and the Sigsbee2A salt model to test the validity and superiority of the proposed method. The results demonstrate that the proposed method could produce the ADCIGs and the stacked image with higher fidelity than RTM, which provides a reliable input for migration velocity analysis, anisotropic model building, and amplitude versus angle analysis.

Turbulence anisotropy and intermittency in open-channel flows on rough beds

An experimental campaign, based on Particle Image Velocimetry measurements in a laboratory flume with different median sediment sizes in the no-motion condition, has been carried out aiming at investigating the effects of bed roughness on turbulence anisotropy in two different vertical zones of the turbulent open-channel flow. An analysis of turbulence anisotropy, which relies on second-order structure functions and anisotropy angle, has been performed. The scale-dependent anisotropy level has been quantified, verifying the tendency of the system to span from large-scale anisotropy, due to the main shear of the boundary layer, to small-scale isotropy. Isotropy is well-established for the largest sediment sizes. High-order structure function analysis reveals that intermittency is more pronounced in the near-bed layers, where the flow is more populated by coherent vortices. Spectral anisotropy and intermittency strongly characterize the transport properties of turbulence and are, therefore, important phenomena for natural bed rivers.

Deformation and Stability Characteristics of Layered Rock Slope Affected by Rainfall Based on Anisotropy of Strength and Hydraulic Conductivity

The strength and hydraulic conductivity anisotropy of rock slopes have a great impact on the slope stability. This study took a layered rock slope in Pulang, Southwestern China as a case study. The strength conversion equations of the seriously weathered rock mass were proposed. Then, considering the anisotropy ratio and anisotropy angle (dip angle of bedding plane) of strength and hydraulic conductivity, the deformation and stability characteristics of rock slope were calculated and compared with field monitoring data. The results showed that the sensitivity analysis of strength and hydraulic conductivity anisotropy could successfully predict the occurrence time, horizontal displacement (HD), and the scope of the rock landslide. When the anisotropy ratio was 0.01 and the dip angle was 30°, the calculated HD and scope of the landslide were consistent with the field monitoring data, which verified the feasibility of the strength conversion equations. The maximum horizontal displacement (MHD) reached the maximum value at the dip angle of 30°, and the MHD reached the minimum value at the dip angle of 60°. When the dip angle was 30°, the overall factor of safety (FS) and the minimum factor of safety (MFS) of the rock slope were the smallest. By assuming that the layered rock slope was homogeneous, the HD and MHD would be underestimated and FS and MFS would be overestimated. The obtained results are likely to provide a theoretical basis for the prediction and monitoring of layered rock landslides.

Anisotropic angle distribution learning for head pose estimation and attention understanding in human-computer interaction

Head pose estimation is an important way to understand human attention in the human-computer interaction. In this paper, we propose a novel anisotropic angle distribution learning (AADL) network for head pose estimation task. Firstly, two key findings are revealed as following: 1) Head pose image variations are different at the yaw and pitch directions with the same pose angle increasing on a fixed central pose; 2) With the fixed angle interval increasing, the image variations increase firstly and then decrease in yaw angle direction. Then, the maximum a posterior technology is employed to construct the head pose estimation network, which includes three parts, such as convolutional layer, covariance pooling layer and output layer. In the output layer, the labels are constructed as the anisotropic angle distributions on the basis of two key findings. And the anisotropic angle distributions are fitted by the 2D Gaussian-like distributions (groundtruth labels). Furthermore, the Kullback-Leibler divergence is selected to measure the predication label and the groundtruth one. The features of head pose images are perceived at the AADL-based convolutional neural network in an end-to-end manner. Experimental results demonstrate that the developed AADL-based labels have several advantages, such as robustness for head pose image missing, insensitivity for the motion blur. Moreover, the proposed method has achieved good performance compared to several state-of-the-art methods on the Pointing’04 and CAS_PEAL_R1 databases.

Uniaxial compressive strength estimation based on the primary wave velocity in coal: considering scale effect and anisotropy

ABSTRACT Coal mass strength estimation has attracted broad attentions for decades. Investigating the effect of scale and anisotropy on the Uniaxial Compressive Strength (UCS) estimation via P-wave velocity is crucial in upscaling the lab-obtained correlation to coal mass strength evaluation. Microstructures were considered as the major impact factors for the scale difference and anisotropy of mechanical properties in coal. Thus, the microstructure correlated influence of specimen sizes and anisotropy angles on the UCS estimation based on the primary wave (P-wave) velocity were investigated here. Specimens with four diameters (25 mm to 75 mm) and six anisotropy angles (angles between bedding plane orientation and coring direction, 0° to 90°) were processed. Roles microstructures played for the P-wave propagation were explored by the X-ray computed tomography scanning and P-wave velocity tests. The UCS estimation via P-wave velocity in coal were investigated by regression analysis, significances of scale and anisotropy effect on this correlation were quantitatively evaluated by an introduced one-way analysis of variance method. P-wave velocity for specimens with different diameters exhibits a U-shaped variation against anisotropy angles, it reduces at anisotropy angles 0° ~ 45°, while raises within that of 45° ~ 90°, the minimum, maximum, and second largest value were acquired, respectively, at the anisotropy angle 45°, 90°, and 0°. This was considered caused by the complementary variation of angles between directions of P-wave propagation and orientations of bedding plane and major cleats. P-wave velocity wakens in larger specimens, velocity reductions are significantly at the anisotropy angle of 45°, while less obviously at 0° and 90°. While the anisotropy of P-wave velocity strengthens as diameters gain. Specimen sizes and anisotropy angles were proved to affect the UCS estimation via P-wave velocity by the one-way analysis of variance. Exponential correlation was verified more appropriate in the UCS estimation via P-wave velocity in coal, specimens with diameter 38 mm and anisotropy angle 45° were proved optimal for the UCS estimating by P-wave velocity in coal, since the correlation between them is stronger than other diameters and anisotropy angles. This research facilitates us in quickly and accurately strength estimating in anisotropy coal, meanwhile, it also provides references in extending the lab-obtained mechanical properties of coal/rock specimens to coal/rock mass.

Anisotropic Vorticity Within Bursty Bulk Flow Turbulence

AbstractUtilizing Magnetospheric Multiscale (MMS) observation in the tail plasma sheet, we study the vorticity field (ω = ∇ × V) of the plasma bulk (convective) velocity within the bursty bulk flow (BBF) in detailed. Two typical events are presented. In the event on 25 June 2017, Ey is the main component. In the other event on 6 July 2017, Ez is the main component. For both cases, the BBF electric field is dominated by the convective electric field (Ec = − V × B). Our case studies show clearly the existence of the convective vorticity field within the BBF. The vorticity field has prominent anisotropy (quantified by the anisotropic angle (θaa = arctan(ω⊥/ω∥)). More often, the BBF ω field has stronger perpendicular vorticity (ω⊥) than the parallel vorticity (ω∥). The dominance of vorticity by ω⊥‐dominating BBF is confirmed in the statistical sense. In particular, event on 25 June shows the significant evolution of the ion flux energy with the strength of the ω field. The strong ω field corresponds to the ion flux enhancement at high energy (above 10 keV), while the weak ω field corresponds to the ion flux enhancement at medium energy (2–5 keV). Investigation of the subset of channel from fast plasma investigation partial moment measurement reveals that the ion behaviors in the strong and decayed BBFs are distinctly different. The channeled ions form the narrow band distribution in the strong BBF but the multiple‐layer distribution in the weak BBF. Finally, spectrum analysis indicates that the BBF ω⊥ and ω∥ have a similar scaling about −2.0 (below 0.2 Hz).

Transfer Durability of Line-Patterned Replica Mold Made of High-Hardness UV-Curable Resin.

Ultraviolet nanoimprint lithography (UV-NIL) requires high durability of the mold for the mass production of nanostructures. To evaluate the durability of a line-patterned replica mold made of high-hardness UV curable resin, repetitive transfer and contact angle measurements of the replica mold were carried out. In the line patterns, as the contact angle decreases due to repeated transfer, capillary action occurs, and water flows along them. Therefore, it can be said that a mold with a line pattern exhibits an anisotropic contact angle because these values vary depending on the direction of the contact angle measurement. Subsequently, these anisotropic characteristics were investigated. It was determined that it was possible to predict the lifetime of line-and-space molds over repeated transfers. As the transcription was repeated, the contact angle along the line patterns decreased significantly before becoming constant. Moreover, the contact angle across the line pattern decreased slowly while maintaining a high contact angle with respect to the contact angle along the line pattern. The contact angle then decreased linearly from approximately 90°. The mold was found to be macroscopically defect when the values of the contact angle along the line pattern and the contact angle across the line pattern were close. Predicting the mold’s lifetime could potentially lead to a shortened durability evaluation time and the avoidance of pattern defects.

Development of Helical Myofiber Tracts in the Human Fetal Heart: Analysis of Myocardial Fiber Formation in the Left Ventricle From the Late Human Embryonic Period Using Diffusion Tensor Magnetic Resonance Imaging

BackgroundDetection of the fiber orientation pattern of the myocardium using diffusion tensor magnetic resonance imaging lags ≈12 weeks of gestational age (WGA) behind fetal myocardial remodeling with invasion by the developing coronary vasculature (8 WGA). We aimed to use diffusion tensor magnetic resonance imaging tractography to characterize the evolution of fiber architecture in the developing human heart from the later embryonic period.Methods and ResultsTwenty human specimens (8–24 WGA) from the Kyoto Collection of Human Embryos and Fetuses, including specimens from the embryonic period (Carnegie stages 20–23), were used. Diffusion tensor magnetic resonance imaging data were acquired with a 7T magnetic resonance system. Fractional anisotropy and helix angle were calculated using standard definitions. In all samples, the fibers ran helically in an organized pattern in both the left and right ventricles. A smooth transmural change in helix angle values (from positive to negative) was detected in all 16 directions of the ventricles. This feature was observed in almost all small (Carnegie stage 23) and large samples. A higher fractional anisotropy value was detected at the outer side of the anterior wall and septum at Carnegie stage 20 to 22, which spread around the ventricular wall at Carnegie stage 23 and in the early fetal samples (11–12 WGA). The fractional anisotropy value of the left ventricular walls decreased in samples with ≥13 WGA, which remained low (≈0.09) in larger samples.ConclusionsFrom the human late embryonic period (from 8 WGA), the helix angle arrangement of the myocardium is comparable to that of the adult, indicating that the myocardial structure blueprint, organization, and integrity are already formed.

Ultralow Switching-Current Density in All-Amorphous W−Hf/Co−Fe−B/TaOx Films

We study current-induced deterministic magnetization switching and domain wall motion via polar Kerr microscopy in all-amorphous W$_{66}$Hf$_{34}$/CoFeB/TaO$_\text{x}$ with perpendicular magnetic anisotropy and large spin Hall angle. Investigations of magnetization switching as a function of in-plane assist field and current pulse-width yield switching current densities as low as $3\times 10^{9}$ A/m$^2$. We accredit this low switching current density to a low depinning current density, which was obtained from measurements of domain wall displacements upon current injection. This correlation is verified by investigations of a Ta/CoFeB/MgO/Ta reference sample, which showed critical current densities of at least one order of magnitude larger, respectively.

Sensitivity Analyses of the Seepage and Stability of Layered Rock Slope Based on the Anisotropy of Hydraulic Conductivity: A Case Study in the Pulang Region of Southwestern China

In the study of the seepage characteristics of layered rock slope under rainfall conditions, the majority of previous research has considered the hydraulic conduction to be isotropic, or only considered the anisotropy ratio of the hydraulic conductivity, ignoring the anisotropy angle. In the current study, a layered rock slope in the Pulang region was selected as an example. Then, based on the fitting parameters of the Van Genuchten model, pore water pressure sensitivity analyses of the layered rock slope were carried out. The anisotropy ratio and anisotropy angle were used to analyze the sensitivity of the seepage and stability of the layered rock slopes. The results show that as the anisotropy angle of hydraulic conductivity of layered rock slope decreased, the maximum volume water content of surface (MWCS) of layered rock slope gradually increased. Additionally, as the anisotropy ratio decreased and the anisotropy angle increased, the rising heights of the groundwater (RHG) of layered rock slope gradually increased. When the hydraulic conduction of layered rock slope was considered isotropic, the factor of safety (FS) tended to be overestimated. As the anisotropy ratio decreased and the anisotropy angle increased, the factor of safety (FS) of layered rock slope decreased. Prevention should be the objective for rock slopes with larger dip angles in the bedding plane in the Pulang region. This study provides feasible schemes for the evaluation of the seepage and stability of layered rock slopes in Pulang region of southwestern China.

Evaluation of the lateral earth pressure in unsaturated soils with finite element limit analysis using second-order cone programming

Abstract This paper aims at studying the active and passive earth pressures on the retaining structures having an unsaturated backfill. To this end, the well-established lower bound limit analysis coupled with the finite element method and the second-order cone programming (SOCP) has been employed to generate the admissible stress field within the soil medium behind the retaining wall. In order to simulate the unsaturated soil condition, the unified effective stress approach is adopted and implemented in the universal Mohr-Coulomb yield criterion. Using the results of several numerical simulations, the influence of various controlling parameters, including flow rate condition, soil–water retention curve (SWRC) and groundwater table level on the response of the retaining wall with an unsaturated backfill is thoroughly examined. Furthermore, the active and passive earth pressures are rigorously evaluated accounting for the variations of the wall height, soil type, effective internal friction angle, soil-wall roughness and soil inherent anisotropy. It is shown that as the existence of suction stress in unsaturated soils results in the greater values of the effective stress, and consequently the soil shear strength, it would lead to the lower active and higher passive lateral pressures exerted on the retaining structure.

Phase-field study of the effects of the multi-controlling parameters on columnar dendrite during directional solidification in hexagonal materials.

The growth of hexagonal columnar dendrite during directional solidification with respect to the multi-controlling parameters such as anisotropy, cooling rate, temperature gradient and orientation angle were investigated by a quantitative phase-field method, respectively. The simulation results show that the increase of anisotropy, cooling rate and temperature gradient can accelerate the solidification velocity of columnar dendrites. Among them, the cooling rate has the most significant effect on the solidification velocity of columnar dendrite. In contrast, the solidification velocity of columnar dendrite slows down with the increase of the orientation angle. Meanwhile, the primary dendrite spacing decreases with the increase of cooling rates and temperature gradient, and the primary dendrite arms are smooth. The primary dendrite spacing increases with the increase of anisotropy and orientation angle, which provides space for the development of secondary dendrite arms. In addition, the effects of cooling rate and temperature gradient on the solid volume fraction were also studied.

Groundwater Throughflow and Seawater Intrusion in High Quality Coastal Aquifers

High quality coastal aquifer systems provide vast quantities of potable groundwater for millions of people worldwide. Managing this setting has economic and environmental consequences. Specific knowledge of the dynamic relationship between fresh terrestrial groundwater discharging to the ocean and seawater intrusion is necessary. We present multi- disciplinary research that assesses the relationships between groundwater throughflow and seawater intrusion. This combines numerical simulation, geophysics, and analysis of more than 30 years of data from a seawater intrusion monitoring site. The monitoring wells are set in a shallow karstic aquifer system located along the southwest coast of Western Australia, where hundreds of gigalitres of fresh groundwater flow into the ocean annually. There is clear evidence for seawater intrusion along this coastal margin. We demonstrate how hydraulic anisotropy will impact on the landward extent of seawater for a given groundwater throughflow. Our examples show how the distance between the ocean and the seawater interface toe can shrink by over 100% after increasing the rotation angle of hydraulic conductivity anisotropy when compared to a homogeneous aquifer. We observe extreme variability in the properties of the shallow aquifer from ground penetrating radar, hand samples, and hydraulic parameters estimated from field measurements. This motived us to complete numerical experiments with sets of spatially correlated random hydraulic conductivity fields, representative of karstic aquifers. The hydraulic conductivity proximal to the zone of submarine groundwater discharge is shown to be significant in determining the overall geometry and landward extent of the seawater interface. Electrical resistivity imaging (ERI) data was acquired and assessed for its ability to recover the seawater interface. Imaging outcomes from field ERI data are compared with simulated ERI outcomes derived from transport modelling with a range of hydraulic conductivity distributions. This process allows for interpretation of the approximate geometry of the seawater interface, however recovery of an accurate resistivity distribution across the wedge and mixing zone remains challenging. We reveal extremes in groundwater velocity, particularly where fresh terrestrial groundwater discharges to the ocean, and across the seawater recirculation cell. An overarching conclusion is that conventional seawater intrusion monitoring wells may not be suitable to constrain numerical simulation of the seawater intrusion. Based on these lessons, we present future options for groundwater monitoring that are specifically designed to quantify the distribution of; (i) high vertical and horizontal pressure gradients, (ii) sharp variations in subsurface flow velocity, (iii) extremes in hydraulic properties, and (iv) rapid changes in groundwater chemistry. These extremes in parameter distribution are common in karstic aquifer systems at the transition from land to ocean. Our research provides new insights into the behaviour of groundwater in dynamic, densely populated, and ecologically sensitive coastal environments found worldwide.