National Research Institute for Earth Science and Disaster Resilience (NIED) integrated the land observation networks established since the 1995 Kobe earthquake with the seafloor observation networks established since the 2011 Tohoku earthquake and tsunami as MOWLAS (Monitoring of Waves on Land and Seafloor) in November 2017. The purpose of MOWLAS is to provide comprehensive, accurate, and rapid observation and monitoring of earthquake, tsunami, and volcano events throughout Japan and its offshore areas. MOWLAS data are widely utilized for long-term earthquake forecasting, the monitoring of current seismic activity, seismic and tsunami hazard assessments, earthquake early warning, tsunami warning, and earthquake engineering, as well as earthquake science. Ocean bottom observations provide an extension of observations to areas where no people are living and have the advantage of increasing lead time of earthquake early warning and tsunami warning. The application of recent technology advancements to real-time observations as well as the processing of MOWLAS data has contributed to the direct disaster mitigation of ongoing earthquakes. These observations are fundamental for both science and disaster resilience, and thus it is necessary to continue ceaseless operation and maintenance.
Understanding the global mass inventory is one of the main challenges in present research on plastic marine debris. Especially the fragmentation and vertical transport processes of oceanic plastic are poorly understood. However, whereas fragmentation rates are unknown, information on plastic emissions, concentrations of plastics in the ocean surface layer (OSL) and fragmentation mechanisms is available. Here, we apply a systems engineering analytical approach and propose a tentative ‘whole ocean’ mass balance model that combines emission data, surface area-normalized plastic fragmentation rates, estimated concentrations in the OSL, and removal from the OSL by sinking. We simulate known plastic abundances in the OSL and calculate an average whole ocean apparent surface area-normalized plastic fragmentation rate constant, given representative radii for macroplastic and microplastic. Simulations show that 99.8% of the plastic that had entered the ocean since 1950 had settled below the OSL by 2016, with an additional 9.4 million tons settling per year. In 2016, the model predicts that of the 0.309 million tons in the OSL, an estimated 83.7% was macroplastic, 13.8% microplastic, and 2.5% was < 0.335 mm ‘nanoplastic’. A zero future emission simulation shows that almost all plastic in the OSL would be removed within three years, implying a fast response time of surface plastic abundance to changes in inputs. The model complements current spatially explicit models, points to future experiments that would inform critical model parameters, and allows for further validation when more experimental and field data become available.
Urban snow management systems are typically treated as logistical operations to remove and dispose of excess snow. However, the Sapporo Glacier concept reframes municipal snow management within a cryospheric systems framework, transforming urban snow accumulation into a controlled cryospheric process that interacts with climate and urban energy systems. This paper presents a hypothesis-driven scoping concept, the Sapporo Glacier, as a conceptual framework for Urban Cryosphere Engineering, which seeks to design and control the long-term storage, insulation, and metamorphism of urban snow using bounded, first-order physical reasoning rather than site-calibrated performance prediction to create a glacier possessing glacier ice (as classically defined) and measurable flow. Using Sapporo City’s existing snow-depot infrastructure as a reference model, the framework integrates physical modeling (degree-day method and simplified energy-balance considerations), surface control through organic mulch, and seasonal monitoring to delineate feasible design regimes for optimizing the thermal state of accumulated snow. Beyond technical feasibility, it emphasizes socio-environmental integration, envisioning snow storage as both a climate-adaptive infrastructure and a cultural landscape that connects citizens to seasonal cycles. Importantly, meltwater released from such an urban glacier during summer may generate a localized, testable nearshore thermal signal, enabling empirical evaluation of coastal cryosphere–ocean interactions. This hypothesis-driven, conceptual approach aims to establish an interdisciplinary foundation for future empirical studies and design experiments, rather than to deliver predictive site-specific outcomes, toward the realization of urban glaciers as sustainable and ecological elements of city life.
Engineering (General). Civil engineering (General), City planning
A constellation of small, low-cost satellites is able to make scientifically valuable measurements of the Earth which can be used for weather forecasting, disaster monitoring, and climate studies. Eight CYGNSS satellites were launched into low Earth orbit on December 15, 2016. Each satellite carries a science radar receiver which measures GPS signals reflected from the Earth surface. The signals contain information about the surface, including wind speed over ocean, and soil moisture and flooding over land. The satellites are distributed around their orbit plane so that measurements can be made more often to capture extreme weather events. Innovative engineering approaches are used to reduce per satellite cost, increase the number in the constellation, and improve temporal sampling. These include the use of differential drag rather than propulsion to adjust the spacing between satellites and the use of existing GPS signals as the science radars’ transmitter. Initial on-orbit results demonstrate the scientific utility of the CYGNSS observations, and suggest that a new paradigm in spaceborne Earth environmental monitoring is possible.
Numerous compounds present in the ocean are contributing to the development of the biomedical field. Agarose, a polysaccharide derived from marine red algae, plays a vital role in biomedical applications because of its reversible temperature-sensitive gelling behavior, excellent mechanical properties, and high biological activity. Natural agarose hydrogel has a single structural composition that prevents it from adapting to complex biological environments. Therefore, agarose can be developed into different forms through physical, biological, and chemical modifications, enabling it to perform optimally in different environments. Agarose biomaterials are being increasingly used for isolation, purification, drug delivery, and tissue engineering, but most are still far from clinical approval. This review classifies and discusses the preparation, modification, and biomedical applications of agarose, focusing on its applications in isolation and purification, wound dressings, drug delivery, tissue engineering, and 3D printing. In addition, it attempts to address the opportunities and challenges associated with the future development of agarose-based biomaterials in the biomedical field. It should help to rationalize the selection of the most suitable functionalized agarose hydrogels for specific applications in the biomedical industry.
In the past two decades, the research on acoustic metamaterials has flourished, which is also benefited from the development of additive manufacturing technology. The exotic physical phenomena and principles exhibited by acoustic metamaterials have attracted widespread attention from academia and engineering communities, which can be applied to noise reduction and acoustic nondestructive testing in industrial; invisible cloaking and camouflage in the military; medical ultrasound imaging in national health; acoustic stealth in defense security, detection in the ocean, communication, and other fields, i.e., acoustic metamaterials have important scientific research value and broad application prospects. This review summarizes the history and research status of acoustic metamaterials, focusing on the main research progress of metamaterials in nonlinear acoustic and acoustic coatings fields, including the research on acoustic coatings with cavities of our group. Finally, the future development direction of acoustic metamaterials is prospected, and the difficulties and challenges faced by the actual engineering of acoustic metamaterials are discussed, such as difficulties in mass production, hydrostatic pressure resistant property, omnidirectional wave control, high production costs, and so on.
ABSTRACT By incorporating the advantages of magnetic gearing effect and claw pole structure, a new type of claw‐pole electric‐excitation field‐modulation (CPEEFM) machine has been developed, which has potential direct‐drive application prospects due to its flexible field regulation ability and high rotor reliability. However, the axial asymmetry and the flux distribution complexity make it difficult to analytically calculate the iron loss. The purpose of this paper is to propose an improved iron loss calculation model for this CPEEFM machine, in which the iron loss coefficients are corrected accordingly by introducing the three‐dimensional (3‐D) flux density distortion rate to fully consider the influence of axial flux distribution in addition to the radial and tangential flux distributions. Taking a 24‐slot/14‐pole CPEEFM machine as an example, its iron loss characteristics under different operation conditions are calculated by the proposed model and compared with the traditional Bertotti model and the 3‐D finite element analysis (FEA) implemented by JMAG software based on Fast Fourier Transform (FFT) model, which shows an acceptable consistency and improved accuracy. Furthermore, a prototype is finally fabricated and the experimental testing is carried out to verify the validity of the proposed iron loss analysis model.
Madeline Olivia, Patrichka Wei-Yi Chen, Clara Natalie Annabel
et al.
Seagrass meadows are recognized for their ecological importance, yet their influence on microbial community structure remains insufficiently characterized. This study examined the effects of seagrass presence on microbial assemblages in a subtropical coastal environment by comparing seagrass habitats to adjacent unvegetated sediments. Microbial abundances, including viruses, bacteria, picophytoplankton (<i>Synechococcus</i> spp. and picoeukaryotes), and heterotrophic nanoflagellates, were quantified using flow cytometry. Viral concentrations were significantly higher in seagrass treatments (2.4–9.2 × 10<sup>6</sup> viruses mL<sup>−1</sup>) than in controls (0.6–2.0 × 10<sup>6</sup> viruses mL<sup>−1</sup>), while bacterial abundances were slightly lower in seagrass treatments (5.1–16.0 × 10<sup>5</sup> cells mL<sup>−1</sup>) than in controls (7.9–16.6 × 10<sup>5</sup> cells mL<sup>−1</sup>). As a result, the virus-to-bacteria ratio (VBR) was significantly elevated in seagrass habitats, suggesting enhanced viral regulation of bacterial populations. Additionally, picophytoplankton and heterotrophic nanoflagellates increased in seagrass incubations, with strong correlations indicating that nanoflagellates are likely major grazers of picophytoplankton. These results highlight the role of seagrass habitats in modulating microbial interactions and emphasize the need to consider habitat-specific characteristics when evaluating microbial dynamics and biogeochemical processes in coastal systems.
Abstract Mercury accumulates in the deep sea, but its ecological impact on deep-sea ecosystems remains poorly understood. We conduct an analysis of 32 sediment cores, comprising 101 layers for the study of metagenomes, and additional 41 global reference sediment metagenomes. These sediment cores are collected from two deep-sea regions: the South China Sea and Mariana Trench, followed by revealing high mercury accumulation in the South China Sea. In these metagenomes, we find that the mercury methylation genes hgcAB are abundant in marginal seas but negligible in open oceans. Genomics result indicates that some Hg-methylating microorganisms affiliated with Desulfobacterota, Spirochaetota, and Zixibacteria in the deep-sea sediments encode MttB, the sole corrinoid-dependent methyltransferase identified in these taxa, which may interact with HgcA to transfer methyl groups from possibly osmolyte-derived trimethylamine for methylation. The demethylation gene merB is widely distributed and exhibits higher abundance in the open ocean. Moreover, we identify a large number of novel Hg demethylating taxa that are associated with horizontal transfer of the merB gene potentially involving methane generation. Our results expand the diversity of Hg-transforming taxa and reveal their unique ecophysiological adaptations in deep-sea sediments.
Rechargeable batteries are widely used as power sources for portable electronics, electric vehicles and smart grids. Their practical performances are, however, largely undermined under extreme conditions, such as in high‐altitude drones, ocean exploration and polar expedition. These extreme environmental conditions not only bring new challenges for batteries but also incur unique battery failure mechanisms. To fill in the gap, it is of great importance to understand the battery failure mechanisms under different extreme conditions and figure out the key parameters that limit battery performances. In this review, the authors start by investigating the key challenges from the viewpoints of ionic/charge transfer, material/interface evolution and electrolyte degradation under different extreme conditions. This is followed by different engineering approaches through electrode materials design, electrolyte modification and battery component optimization to enhance practical battery performances. Finally, a short perspective is provided about the future development of rechargeable batteries under extreme conditions.
Abstract In this article, our focus is to extract the diverse exact solutions to the conformable time-fractional modified nonlinear Schrodinger equation (CTFMNLSE) that describes the propagation of water waves in the ocean engineering. Diverse exact solutions like trigonometric, hyperbolic and exponential function solutions are extracted. We also secure some other special wave solutions in the forms of shock wave, singular, multiple and mixed complex solitons. The generalized exponential rational function method (GERFM) is used to explain the dynamics of soliton to CTFMNLSE. Furthermore, the constraint conditions for the existence of solutions are reported also singular periodic wave solutions are recovered. Besides, the accomplished solutions are beneficial to interpretation of the wave propagation study and also important for numerical and experimental verifications in ocean engineering
Abstract In this work, we investigate the dynamical study of the (1+1)-dimensional Mikhailov-Novikov-Wang (MNW) equation via the unified method is investigated. This technique is used to obtain the soliton solutions, including the trigonometric function solution, the periodic function solution, the exponential function solution, the elliptic function solution, and other soliton-form solutions. All the obtained results in this work utilizing an effective unified method help gain a better understanding of the physical meaning and behavior of the equation, thus sheding light on the significance of investigating diverse nonlinear wave phenomena in physics and ocean engineering. These derived results are entirely new and never repeated in the previous works done by the other authors. For the interest of visual presentation and physical illustrations, we plot the graphical demonstrations of some of the specified solutions in 3-dimensional, contour, and 2-dimensional plots by using Mathematica software. Consequently, we observe that the acquired solutions of the MNW equations are anti-bell-shape, kink wave solution, solitary wave, periodic solution, multisoliton, and different types of soliton solutions.
The Landau-Ginzburg-Higgs (LGH) equation explains the ocean engineering models, superconductivity and drift cyclotron waves in radially inhomogeneous plasma for coherent ion-cyclotron waves. In this paper, with a simple modification of the Ablowitz-Kaup-Newell-Segur (AKNS) formalism, the integrability of LGH equation is proved by deriving the Lax pair. Hence for that, the inverse scattering transformation (IST) is applied, and the travelling wave solutions are obtained and graphically represented in 2d and 3d profiles.