Particle Flux Research Articles (Page 3)

The aim of this study was to develop and optimize α-arbutin-loaded nanostructured lipid carriers (Ar- NLCs) using the QbD. Additionally, the formulation studies, in-vitro and ex-vivo performance of Ar-NLCs were assessed, along with their cytotoxic efficacy in melanoma cells. The Ar-NLCs were fabricated using the high-speed homogenization-ultrasonication method, incorporating Gelucire 48/16, Castor oil, Capryol 90, and Tween 80. To analyze the impact of factors on Ar-NLCs, the Box-Behnken design (BBD) was utilized. The Ar-NLCs were characterized by particle size, polydispersity index, morphology, zeta potential, release kinetics, permeation, flux and stability. Additionally, Ar-NLCs cytotoxicity was assessed using the A375 cells. The Ar-NLCs demonstrated a particle size of 228.7 ± 44.5 nm, a zeta potential of -14.2 ± 2.64 mV respectively. The entrapment efficiency was 67.62 ± 4.46%. The α- arbutin release from NLCs followed Weibull kinetics. Notably, Ar-NLCs demonstrated a 2.53-fold higher permeability compared to Ar-SOL. Furthermore, Ar-NLCs exhibited significantly stronger cytotoxic effects against melanoma cells than Ar-SOL. This study reports the successful development of Ar-NLCs using a QbD approach. Enhanced transdermal permeability, enhanced cytotoxicity on melanoma cells, and sustained release of α-arbutin from NLCs were achieved. These findings indicate that NLCs offer a viable alternative drug delivery system for transdermal applications.

In the past decade, hundreds of exoplanets have been discovered in extremely short orbits below 10 days. Unlike in the Solar System, planets in these systems orbit their host stars close enough to disturb the stellar magnetic field lines1. The interaction can enhance the magnetic activity of the star, such as its chromospheric2 and radio3 emission or flaring4. So far, the search for magnetic star-planet interactions has remained inconclusive. Here we report the detection of planet-induced flares on HIP 67522, a 17 million-year-old G dwarf star with two known close-in planets5,6. Combining space-borne photometry from the Transiting Exoplanet Survey Satellite and dedicated Characterising Exoplanets Telescope observations over 5 years, we find that the 15 flares in HIP 67522 cluster near the transit phase of the innermost planet, indicating persistent magnetic star-planet interaction in the system. The stability of interaction implies that the innermost planet is continuously self-inflicting a six times higher flare rate than it would experience without interaction. The subsequent flux of energetic radiation and particles bombarding HIP 67522 b may explain the remarkably extended atmosphere of the planet, recently detected with the James Webb Space Telescope7. HIP 67522 is, therefore, an archetype to understand the impact of magnetic star-planet interaction on the atmospheres of nascent exoplanets.

As global energy demands rise, the advancement of new energy technologies increasingly relies on the development of metals that can endure extreme pressures, temperatures, and fluxes of energetic particles and photons, as well as aggressive chemical reactions. One way to assist in the design and manufacturing of metals for the future is by learning from their past. Here we track the progress of metallic materials for extreme environments in the past 35 years using the text mining method, which allows us to discover patterns from a large scale of literature in the field. Specifically, we leverage transfer learning and dynamic word embeddings. Approximately one million relevant abstracts ranging from 1989 to 2023 were collected from the Web of Science. The literature was then mapped to a 200-dimensional vector space, generating time-series word embeddings across six time periods. Subsequent orthogonal Procrustes analysis was employed to align and compare vectors across these periods, overcoming challenges posed by training randomness and the non-uniqueness of singular value decomposition. This enabled the comparison of the semantic evolution of terms related to metals under extreme conditions. The model’s performance was evaluated using inputs categorized into materials, properties, and applications, demonstrating its ability to identify relevant metallic materials to the three input categories. The study also revealed the temporal changes in keyword associations, indicating shifts in research focus or industrial interest towards high-performance alloys for applications in aerospace and biomedical engineering, among others. This showcases the model’s capability to track the progress in metallic materials for extreme environments over time.

Abstract Radiative divertor detachment with impurity seeding is considered one of the most promising means for mitigating particle and heat fluxes on the divertor target. To measure the impurity radiation distribution, a tangentially viewing camera system for lower divertor plasma observation has been developed and installed on EAST. A reconstructed 2D distribution of N II line radiation is obtained based on Phillips–Tikhonov regularization, revealing the electron temperature region in the range of 6–10 eV during a nitrogen (N2) seeding experiment. With N2 seeding, the deep detachment with the stable X-point radiator (XPR) has been achieved on EAST with a tungsten divertor and metal first wall components. The profiles of T et and q t with a distance to the strike point larger than 6 cm (ρ ∼ 1.06) are radially flat on the outer divertor target in the deeply detached state. The XPR contributes to the effective divertor protection with mitigation of heat/particle fluxes and suppression of divertor target sputtering.

Abstract The biological carbon pump contributes to set the magnitude of carbon sequestration in the oceans' interior. Estimating the relative contribution of microbial versus zooplankton‐mediated processes to particulate organic carbon (POC) flux attenuation provides insights into how this pump functions. Our study took place during the high productivity summer period in the Subantarctic and Polar Front Zone. In the upper mesopelagic (i.e., 180–300 m depth), we concurrently measured the downward POC flux, particle size and morphology, microbial remineralization rates and estimated size‐specific sinking velocities. These concomitant measurements revealed two different export systems, dominated by fecal material in the Subantarctic, and phyto‐aggregates in polar waters. These two systems were characterized by similar low particle sinking velocities (∼10 m d−1), while microbial remineralization rates differed by an order of magnitude. Higher microbial remineralization rates in the Subantarctic (0.11 d−1), compared to polar waters (0.04 d−1), were likely driven by the confounding effect of temperature and particle characteristics. Despite this difference in microbial remineralization rates, these two export systems were characterized by relatively similar transfer efficiencies, suggesting that microbes had differing influences. A comparison of microbially mediated (i.e., scaled using observed remineralization rates) with total POC flux attenuation (i.e., driven by the dual impact of microbes and flux‐feeders) revealed a higher microbial contribution to the flux attenuation in the upper mesopelagic of the subantarctic compared to the polar region. This deconstruction of the flux attenuation revealed an increasing influence of microbes on POC degradation with depth to become the predominant actor in the lower mesopelagic.

Abstract In this study, we introduce observing system simulation experiments (OSSE) and observing system experiments (OSE) to reconstruct the near‐Earth radiation environment. This study investigates the impact of satellite measurements on different orbits and the number of spacecraft measuring the particle fluxes on the reconstruction of the radiation environment at Geostationary (GEO) orbit. We also test the sensitivity of the reconstruction of the environment to the assumed parameters of the model. The results indicate that blending the model with data, even from a single spacecraft at low Earth orbit (LEO), may significantly improve the outer belt reconstruction compared to a reconstruction without data. Additionally, the highest accuracy is achieved when multiple satellites at different orbits covering various radial distances are used. Future improvements to the model are identified. The discrepancies between the observed GEO environment and the environment reconstructed from LEO data may be stronger during storms and should be better understood. Results of the OSE may be included in synthetic data runs representing the “truth,” the so‐called nature run, to provide a more realistic baseline for the OSSEs. When there is an abundance of observations at all radial distances, energies, and pitch angles, the assumptions of the code become less important as data provides enough information to constrain even an inaccurate model. This study gives an example of OSSEs and OSEs and paves the way for the routine application of the OSE and OSSE for mission planning.

The results of trajectory simulation of charged particles through retarding mesh electrodes show why high energy resolution is reached with Retarding Field Analyzers (RFAs). The transmission function is obtained by adding all transmitted particles over the mesh aperture area for a specific kinetic energy of the particles. The transmitted trajectories are classified into different categories having single or multiple deflections. Each category contributes differently to building up the transmission function. The transmission function has a well-defined energy threshold followed by a steep increase giving a high energy resolution. The derivative of the transmission function gives the filtering function for a monoenergetic particle flux. Its shape is close to a right-angle triangular peak. The energy resolution measured as the full width at half maximum of the peak is derived from the strength of the electrostatic fields applied to the retarding mesh electrode. The transmission is calculated using relative units allowing scaling to a specific experimental configuration, and formulas are deducted to estimate the energy resolution. A RFA using a single mesh electrode able to reach an energy resolution of less than 1eV at 8keV beam energy illustrates these calculations.

The TraX Engine is an advanced data processing tool developed by ADVACAM in collaboration with the European Space Agency (ESA), specifically designed for analyzing data from Timepix detectors. This software supports the processing of data from Timepix1, Timepix2, and Timepix3 detectors, which are equipped with various sensor materials (Si, CdTe, GaAs, SiC) and operate in multiple modes (frame-based and data-driven). TraX Engine is capable of processing large datasets across various scientific and medical applications, including space radiation monitoring, particle therapy, and imaging. In space applications, the TraX Engine has been used to process data from satellites like OneWeb JoeySat deployed in LEO orbit, where it continuously monitors space radiation environments measuring flux, dose, and dose rate in real time. In medical applications, particularly in particle therapy, the TraX Engine is used to process data to characterize radiation fields in terms of particle flux, Linear Energy Transfer (LET), and spatial distribution of the radiation dose. The TraX Engine can identify and classify scattered particles, such as secondary protons and electrons, and estimate their contribution to out-of-field doses, a crucial factor in improving treatment planning and reducing the risk of secondary cancers. In imaging applications, the TraX Engine is integrated into Compton cameras, where it supports photon source localization through directional reconstruction of photons. The system's ability to identify the source of gamma radiation with high precision makes it suitable for medical imaging tasks, such as tracking I-131 used in thyroid cancer treatment or localizing radiation sources. This paper presents the architecture and capabilities of the newly developed software TraX Engine, alongside results from various applications, demonstrating its role in particle tracking, radiation monitoring, imaging and others. With its modular architecture, the TraX Engine offers multiple interfaces, including a command-line tool, an API, a web portal and a graphical user interface, ensuring usability across different fields and user expertise levels.

We present recent experiments on an innovative alpha particle detection system, designed to investigate charged particle confinement and transport in high magnetic fields. Our test platform operates within a 3-T Siemens MRI superconducting magnet, providing a large cross-section (~ 40 cm diameter) for studying the behavior of charged particles in an aluminum vacuum can that is inserted into a uniform 3 T magnetic field. Using Americium-241 (241Am) sources placed inside this cylindrical vacuum chamber, we conducted simulations and experiments to measure and analyze alpha particle flux. This system enables the study of fundamental charged particle dynamics, which are relevant to a variety of applications, including nuclear propulsion concepts. Alpha particles serve as a surrogate for fission fragments due to their similar charge-to-mass ratio and comparable velocity, allowing us to explore key physical mechanisms that could influence the confinement and transport of fission fragments in future propulsion systems, specifically a fission fragment rocket engine (FFRE). This much more efficient nuclear rocket propulsion FFRE design was first proposed in the 1980s with the intent of greatly reducing transit times in long-duration space travel. Our objective is to enhance the operational efficiency of this nuclear rocket while gaining deeper insights into the behavior of fuel particles and of the fission-fragment ejecta within strong magnetic fields experimentally. The methodologies developed in this study establish a foundation for future experimental studies involving FFRE. More broadly, this work introduces a versatile approach for analyzing ion flux and nuclear reaction fragments across various experimental platforms.

Crewed interplanetary return missions that are on the planning horizon will take years, more than enough time for initiation and completion of a pregnancy. Pregnancy is viewed as a sequence of processes - fertilization, blastocyst formation, implantation, gastrulation, placentation, organogenesis, gross morphogenesis, birth and neonatal development - each of which needs to be completed successfully, and each of which has a probability of success. The effects of the environment of interplanetary flight - microgravity and galactic cosmic rays (GCR) - on these probabilities are inferred from Earth and low Earth orbit experiments and observations and current models of morphogenesis. The principal hazards for intrauterine development are due to interactions with GCRs, where a variable flux of high energy particles would be interacting with a growing embryonic and fetal target volume, and produce linear tracks of ionization-associated damage. Short term damage would be predominantly mediated via reactive oxygen species, and long-term damage via DNA. Exposure to GCRs is expected to increase the probabilities of implantation failure and of premature labour. A live healthy birth would be possible, but its likelihood reduced. The long time scale of growth and development of the neonatal brain makes delayed manifestation of neurological or behavioural disorders likely.

Neutron monitors (NMs), located at different points on the planet, allow us to study the time, energy, and angular characteristics of galactic and solar particle fluxes. Since NMs are located inside Earth's magnetosphere, their response depends on their location on the planet's surface, which can be characterized by the geomagnetic cutoff rigidity. Its calculation depends on the magnetic field model, the date, and even on numerical methods. The paper presents calculated geomagnetic cutoff rigidities at the locations of some neutron monitors and compares the cutoff values with the calculation results obtained by other authors, including a comparison of the time dynamics over the past decade. We show that the geomagnetic cutoff rigidities obtained for 2020 by the IGRF-14 model differ from those derived by IGRF-13; however, for 2015 the difference between the models is negligible. We demonstrate a tendency for the geomagnetic cutoff rigidity to decrease over time, especially at midlatitudes. Comparison of the obtained geomagnetic cutoff rigidities with those obtained by other authors has shown that in most cases the difference does not exceed 0.2 GV. Such discrepancies are significant only in the circumpolar region, where particles are mostly shielded by Earth’s atmosphere rather than by the geomagnetic field. We show that the accuracy of the algorithm in use is comparable to that of other existing instruments and is sufficient for calculating neutron monitor responses.

Neutron monitors (NMs), located at different points on the planet, allow us to study the time, energy, and angular characteristics of galactic and solar particle fluxes. Since NMs are located inside Earth's magnetosphere, their response depends on their location on the planet's surface that can be characterized by the geomagnetic cutoff rigidity. Its calculation depends on the magnetic field model, the date, and even on numerical methods. The paper presents calculated geomagnetic cutoff rigidities at the locations of some neutron monitors, and compares the cutoff values with the calculation results obtained by other authors, including a comparison of the time dynamics over the past decade. We show that the geomagnetic cutoff rigidities obtained for 2020 by the IGRF-14 model differ from those derived by IGRF-13; however, for 2015 the difference between the models is negligible. We demonstrate a tendency for the geomagnetic cutoff rigidity to decrease over time, especially at midlatitudes. Comparison of the obtained geomagnetic cutoff rigidities with those obtained by other authors has shown that in most cases the difference does not exceed 0.2 GV. Such discrepancies are significant only in the circumpolar region, where particles are mostly shielded by Earth’s atmosphere rather than by the geomagnetic field. We show that the accuracy of the algorithm in use is comparable to that of other existing instruments and is sufficient for calculating neutron monitor responses.

Numerical simulations of edge plasmas are essential for optimizing divertor designs in fusion reactors. The neutral source terms in plasma fluid simulations are typically computed using the Monte Carlo method, which is computationally expensive and constitutes a bottleneck for simulation efficiency. To accelerate edge plasma simulations, this study investigates the feasibility of applying deep learning on the calculation of neutral source terms. Transformers excel at capturing sequence relationships and performing parallel computations, making them well-suited for modeling interactions between various nodes in complex data structures. A Transformer-based neural network (NN) is thus employed to learn the mapping from plasma backgrounds to neutral source terms. The model is trained and evaluated on a data set of approximately 600 samples obtained by SOLPS-ITER simulations of pure deuterium under a typical EAST upper single-null configuration. Subsequent tests show that it achieves relative errors of ~ 5% and ~ 3% at the peak values of particle and electron energy sources, respectively, and relatively large errors for momentum and ion energy sources, reaching up to ~ 20%. Coupled B2.5-NN simulations demonstrate acceptable accuracy for preliminary divertor design assessments, with relative errors below 5% in peak particle and heat flux densities at divertor targets. The computational time per simulation time step is reduced by 80%–90%, underscoring the potential of deep learning in enhancing the efficiency of edge plasma simulations. Nevertheless, the present NN model does not yet provide physical understanding or reliable extrapolation. This remains an important direction for future research.

Abstract Sedimentary 231Pa/230Th has been used as a proxy for understanding changes in ocean circulation and productivity over the last glacial–interglacial cycle. Its application relies on the influence of meridional overturning circulation (MOC) and particle scavenging on the distribution of 231Pa and 230Th in the water column and sediments. While previous studies have addressed the role of MOC on the 230Th and 231Pa water profiles and sedimentary 231Pa/230Th in the Atlantic and Pacific Oceans, including the influence of boundary scavenging in the latter, the impact of these processes in the Indian Ocean remains unresolved. This study employs a two‐dimensional scavenging model with prescribed overturning schemes to simulate the latitudinal distribution of 230Th and 231Pa in the water column and sediments of the Indian Ocean. The water column profiles of both nuclides deviate from linearity, reflecting the influence of deep convection, advection, and upwelling controlled by MOC. Additionally, bottom scavenging within the nepheloid layer and boundary scavenging significantly depletes 231Pa in the Madagascar Basin. The gradual decrease in sediment 231Pa/230Th below 1500 m in the main basins is primarily linked to MOC, while boundary scavenging contributes to systematically lowering the 231Pa/230Th. These findings point to the potential of sedimentary 231Pa/230Th as a proxy for studying the alteration of deep ocean circulation and particle flux in the Indian Ocean.

Abstract Getting fast and reliable predictions of turbulent transport properties is an important challenge in magnetic fusion. Previous research (Heinonen and Diamond 2020 Phys. Rev. E 101 061201) proposed a data-driven approach using neural networks to predict the particle flux and Reynolds stress in a minimal model of drift-wave turbulence. The present work extends this approach to the interchange instability driven by the magnetic curvature. This study highlights the importance of assessing the reliability of data-driven models, especially in view of their application to more complex high-fidelity simulations. In particular, a figure of merit is introduced to identify regions of the input space where the model’s predictions cannot be trusted. The data-driven model predictions are used to gain insight into the vorticity gradient’s contribution to the turbulent flux and the antiviscous nature of the Reynolds stress.

Abstract In the EAST tokamak, the divertor particle flux profiles in L- and H-mode plasmas with modulated lower hybrid current drive (LHCD) power in the upper single null configuration are analyzed using a theoretical model profile by a nonlinear least square fitting method. The fitting analysis successfully derives time evolutions of the strike-line positions as well as the effective widths of the scrape-off-layer (SOL) and private flux region for the particle flux, distinguishing respective effects of the LHCD power and edge localized modes (ELMs). For the studies, power deposition area of the LHCD power is estimated by using extreme ultraviolet radiation signals from the SOL. When an appreciable amount of the LHCD power is deposited in the SOL region, a significant expansion of the divertor particle flux profiles on the upper-outboard side by the LHCD power input is observed in an ELMy H-mode plasma. The upstream electron density profile measured is also considerably expanded by the LHCD power. The observed divertor particle flux profile is qualitatively explained by the additional expansion of the upstream density profile due to the LHCD effects. However, the particle flux profiles on the upper-inboard side do not show noticeable changes. The divertor strike-line positions on both sides and the loop voltage do not show any responses to the LHCD power. On the other hand, when the LHCD power is dominantly deposited in the core region of the L-mode plasma, the SOL particle widths are not simply increased. The SOL widths and the divertor strike-line positions on both sides are clearly modulated by the LHCD power modulation. In the H-mode plasma, low frequency density fluctuations less than ∼50 kHz in the SOL having low poloidal wavenumber less than 2 c m − 1 are noticeably suppressed in the SOL during the LHCD power-on phase. This fact suggests that the observed expansion of the divertor particle flux profiles is not caused by enhanced SOL turbulence. E × B drifts by electrical biasing of the SOL flux tube realized by appreciable LHCD power deposition in the SOL are proposed as a likely candidate mechanism for the interpretation of the experimental observations.

Abstract The particle transport in the region close to the separatrix of L-mode tokamak plasmas is analyzed using local gyrokinetic simulations with the Gyro-kinetic Electromagnetic Numerical Experiment code and the reduced turbulent transport model TGLF-sat2. Experimental data from the ASDEX Upgrade tokamak with scans in density, plasma current and input power is used as a starting point for the study. Both the gyrokinetic simulations and the TGLF-sat2 simulations predict a strong particle pinch in the edge region close to the separatrix. The strong inward pinch leads to the formation of peaked density profiles even in absence of particle sources in all the condition analyzed. The predicted normalized density gradient at zero particle flux reaches level around 50% of the experimental normalized density gradient. These results indicate that not only the particle source but also turbulence plays a strong role for the edge density peaking in L-mode conditions. A direct consequence is that, even in absence of particle source, for a fixed level of the separatrix density, a minimum level of the plasma averaged density is expected. This might pose limitations in terms of plasma average density and separatrix density combinations in future reactors.

Abstract. Ocean warming and Arctic sea-ice decline are expected to affect the biological pump efficiency by altering the timing, quantity, quality, and composition of export production. However, the origins and composition of sinking organic matter are still generally understudied for the oceans, especially in ice-covered areas. Here, we use the compound-specific isotope analysis (CSIA) of amino acids (AAs) to investigate the sources and composition of exported organic matter from a sediment-trap-derived time series of sinking particles collected at depths of 469 and 915 m at the edge of Saglek Bank in the northwestern Labrador Sea from October 2017 to July 2019. The outer edge of Saglek Bank is located at the confluence of cold and fresh Arctic outflow and relatively warmer Atlantic waters. The area is subject to seasonal sea-ice cover and is a biological hotspot for benthic organisms, including deep-sea corals and sponges. Sea ice was present for ∼ 50 % to 60 % of the deployment days in both cycles. Phytoplankton blooms at our study site co-occurred with the onset of sea-ice melt. Microalgal taxonomy indicated the presence of ice-associated diatoms in the sinking particles during the spring bloom in 2018, confirming that sea-ice algae contributed to the organic particle export at our study site. The presence of abundant copepods and copepod nauplii caught in the sediment traps was consistent with a high abundance of copepods in overlying epipelagic waters. Stable carbon isotopes (δ13C) of essential amino acids (EAAs) of the sinking particles revealed a potentially important contribution of sea-ice algae as a carbon source at the base of the food web to sinking particles, with only minor modification by microbial resynthesis. Stable nitrogen isotopes (δ15N) of AAs of sinking particles provided independent evidence of the minor bacterial degradation, and Bayesian mixing models based on normalized δ15N-AA values revealed the dominant contribution of fecal pellets (76 %–96 %) to the sinking particles. Our study demonstrates the importance of sea-ice algae and fecal pellets to the biological pump in the seasonally ice-covered northwestern Labrador Sea, with sea-ice algae exported either directly via passive sinking or indirectly via zooplankton grazing and with fecal pellets dominating the organic particle fluxes.

Abstract The divertor detachment is important for the improved confinement mode (I-mode) to serve as a reliable operating scenario in future fusion reactors. A reproducible steady-state I-mode operation with the energy detachment of the inner target has been achieved with the lower single-null configuration on the Experimental Advanced Superconducting Tokamak (EAST). Compared to the high confinement mode (H-mode), I-mode has a lower electron temperature on the inner divertor target and can achieve energy detachment at a lower density. In addition, dedicated experiments on neon (Ne) seeding to assist the exhaust of steady-state heat flux in I-mode discharges have also been successfully carried out on EAST. A significant reduction of the particle flux caused by the Ne impurity radiation was observed at both inner and outer divertor targets without I-L back-transition on EAST for the first time. This may be due to the ‘corner effect’ of the EAST right-angled divertor with a high divertor closure, which can effectively trap the impurity particles and thus reduce the influence of impurity on the main plasma. Furthermore, good core-edge compatibility was also obtained in the detached I-mode plasma with a radiative divertor. This study offers an attractive scenario of I-mode operation for avoiding excessively high transient and steady-state heat loads simultaneously in future fusion reactors.

Abstract A major pathway in the biological carbon pump is the gravitational sinking of organic particles from the sunlit ocean (0–200 m) to the deep ocean. Variability in particle fluxes measured by sediment traps is often attributed to variability in primary production in the surface ocean. However, particle fluxes are also influenced by physical processes such as mesoscale eddies and fronts. In this study, we assess the impact of upper‐ocean dynamical structures on the variability of particle collection in the deep ocean. This is achieved by forward tracking the trajectories of 51.9 million virtual particles that were homogeneously released at a depth of 200 m with a constant sinking velocity of 50 m in the Northeast Atlantic basin. We found that, despite a homogeneous particle source without biological effects, purely dynamical changes can induce heterogeneity in particle density and origin at depth. The position of sediment traps can thus significantly influence the weekly to seasonal particle collection in the deep ocean. Additionally, we identify and characterize nine particle clusters using a machine‐learning approach. The results show that the seasonality of particle collection at depth can be induced by seasonal variations in upper‐ocean flow structures. Clusters associated with eddy and frontal structures are found to intermittently contribute more than 50% of the particle amount during winter and spring, with smaller secondary peaks in the summer months. This study highlights the connection between mesoscale ocean dynamics and the spatio‐temporal pattern of conservative (non‐biological) particle collection in the deep ocean.