High Current Speed Research Articles

Simulation study on submarine trench gravel dumping under the influence of hydrodynamics

Abstract Gravel drift under the hydrodynamic effect is a significant problem during gravel dumping operations in coastal areas, which has a great impact on construction efficiency. Based on the Zhangpu submarine pipeline project, this paper investigated the drift distance and underwater distribution characteristics of gravel during the process of submarine trench gravel dumping under the influence of hydrodynamics by using the computational fluid dynamics (CFD) method. The results show that the greater the water depth and current speed is, the farther the drift distance of gravel along the current direction is. The water current has the most significant effect on the underwater distribution of gravel. The larger the current velocity is, the larger the underwater distribution width of gravel after sinking to the bottom is, and the larger the loss rate of gravel which has not been thrown to the required range is. The construction work should be avoided under high current speed conditions when carrying out gravel dumping.

Estimating common whelk (Buccinum undatum) abundance using baited remote underwater video (BRUV)

Abstract Baited static gear fisheries targeting benthic invertebrates have expanded at a global scale. While improvements have been made in the monitoring and management of these fisheries, reliable survey methods for stock assessments of many key species are lacking. In this study we examine the viability of a baited remote underwater video (BRUV) system for obtaining abundance indices for a data-limited stock (common whelk, Buccinum undatum), and compare this method to catch per unit effort (CPUE) from commercial fishing. BRUVs capable of collecting 15 hours of timelapse footage were deployed on pot strings in two distinct whelk fishing sites, with replication over a spring-neap tidal cycle. Three potential BRUV metrics—the maximum (MaxN) and mean (MeanN) abundance and time of first arrival (T1)—were calculated for each deployment, and significant linear relationships were identified between MaxN, MeanN, and CPUE across sites. Temporal variability in BRUV indices driven by tidal dynamics was minimal, although results suggest high current speeds may reduce abundance estimates, and a potential method for predicting density on the seabed using arrival rates is also demonstrated. BRUVs are a valuable tool in developing stock assessment surveys for static gear fisheries.

Shell shape variation of the symbiotic gastropod Phenacovolva rosea in Vietnam

This study investigates the shell variability of Phenacovolva rosea, a symbiotic gastropod inhabiting octocorals, in relation to geographical location and host coral species. We analyzed shells from 53 adult specimens collected at three locations in the north of Vietnam and one in the vicinities of Nha Trang City (southern Vietnam). To describe the shells' outlines, elliptical Fourier descriptors were applied. Based on the shell outline data, principal component analysis was performed. Additionally, height and width of P. rosea shells were measured. Only the first two principal components were effective, with the first principal component accounting for 92.8% of the variation. It closely correlated with width-to-height ratio of shells. According to dispersion analysis (ANOVA), shells in Nha Trang were significantly slimmer with longer terminal processes compared to those from the three northern locations. The coral host species also impacted shell shape when considering the entire dataset. However, this difference may have stemmed from shell variations between locations, as coral composition is not independent of location. When regional samples were analyzed separately, no significant impact of the host was detected. The factors that differed between northern locations and Nha Trang were then discussed, along with the mechanisms underlying their influence. We suggest that predation risk, influenced by water turbidity, is greater in the clearer waters of Nha Trang. This increased predator pressure may explain the presence of long terminals on P. rosea shells found in Nha Trang, potentially providing protection against some fish predators. Furthermore, the shorter and wider shells found in northern locations may be advantageous in waters with higher current speeds, whereas the long-teminal shells with narrow apertures observed in Nha Trang may be better suited for slower currents. The climate disparity, encompassing temperature and salinity mediated through precipitation, could also potentially influence shell morphology. However, the underlying mechanism remains unclear due to the complex nature of these interactions and the scarcity of literature data. Isolating host-specific shell shape traits from other factors proved challenging, given the close association between host species composition and location. Laboratory experiments modeling each factor independently may provide a solution to this issue.

NUMERICAL ANALYSIS OF STEEL MEMBER REMAINING COMPRESSIVE CAPACITY DURING SMAW WELDING

This study investigates the influence of Shielded Metal Arc Welding (SMAW) welding parameters on the remaining compressive capacity of angle-shaped steel members used for structural strengthening. The analysis focuses on members with thin hot-rolled profiles (40.4 x 40.4 x 4.0 mm, 50.5 x 50.5 x 5.0 mm, and 60.6 x 60.6 x 6.0 mm). A finite element model simulates the heat distribution caused by welding, leading to a temperature increase within the member. Welding scenarios are simulated using various combinations of current strength and welding speed based on the specifications for electrode type E6013. The remaining compressive capacity is determined by segmenting the cross-section based on temperature intervals and considering the member's slenderness. The analysis reveals a clear correlation between welding parameters and compressive capacity loss. Employing a higher current and lower welding speed leads to a more significant reduction in capacity due to the resulting extensive heat-affected zone (HAZ). Conversely, the lowest current and highest speed scenario minimizes the HAZ, resulting in the highest remaining compressive capacity. The analysis demonstrates that the 40.4 x 40.4 x 4.0 mm member can retain up to 51.15% of its original capacity under these optimal conditions, while the 50.5 x 50.5 x 5.0 mm and 60.6 x 60.6 x 6.0 mm members can retain 57.79% and 75.78%, respectively. In contrast, the worst-case scenario employing high current and low speed significantly reduces the remaining capacity, with reductions down to 6.79%, 10.87%, and 10.54% for the respective member sizes. These findings highlight the importance of optimizing welding parameters to minimize the negative impact on the compressive capacity of steel members during strengthening operations.

Capturing accurate kelp canopy extent: integrating tides, currents, and species-level morphology in kelp remote sensing

Surface-canopy forming kelps (Macrocystis pyrifera and Nereocystis luetkeana) can be monitored along the Northeast Pacific coast using remote sensing. These kelp canopies can be submerged by tides and currents, making it difficult to accurately determine their extent with remote sensing techniques. Further, both species have morphologically distinct canopies, each made up of structures with differing buoyancies, and it is not well understood whether the differing buoyancies between these species’ canopies affects their detectability with remote sensing technologies. Here, we collected in situ above-water spectral signatures for the surface-canopies of Nereocystis and Macrocystis, providing the first direct hyperspectral comparison between the structures that make up the canopies of these species. Additionally, we compare the strength of their red-edge and near-infrared band signals, as well as the normalized difference red-edge (NDRE) and normalized difference vegetation index (NDVI) values. At the bed level, we compare detection of kelp canopy extent using both NDRE and NDVI classified unoccupied aerial vehicle imagery. We also characterized how changing tides and currents submerge the canopies of both species, providing insights that will allow remote sensors to more accurately determine the extent of kelp canopy in remote sensing imagery. Observations of canopy structures paired with in situ hyperspectral data and simulated multispectral data showed that more buoyant kelp structures had higher reflectance in the near-infrared wavelengths, but even slightly submerged canopy structures had a higher reflectance in the red-edge rather than the near-infrared. The higher red-edge signal was also evident at the bed level in the UAV imagery, resulting in 18.0% more canopy classified with NDRE than with NDVI. The area of detected canopy extent decreased by an average of 22.5% per meter of tidal increase at low current speeds (<10 cm/s), regardless of the species present. However, at higher current speeds (up to 19 cm/s), Nereocystis canopy decreased at nearly twice the average rate of kelp beds in low-current conditions. Apart from the strong differences in high-current regions, a robust linear relationship exists between kelp canopy extent and tidal height, which can aid in understanding the errors associated with remote sensing imagery collected at different tidal heights.

Flexible switch matrix addressable electrode arrays with organic electrochemical transistor and pn diode technology

Due to their effective ionic-to-electronic signal conversion and mechanical flexibility, organic neural implants hold considerable promise for biocompatible neural interfaces. Current approaches are, however, primarily limited to passive electrodes due to a lack of circuit components to realize complex active circuits at the front-end. Here, we introduce a p-n organic electrochemical diode using complementary p- and n-type conducting polymer films embedded in a 15-μm -diameter vertical stack. Leveraging the efficient motion of encapsulated cations inside this polymer stack and the opposite doping mechanisms of the constituent polymers, we demonstrate high current rectification ratios (105\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${10}^{5}$$\\end{document}) and fast switching speeds (230 μs). We integrate p-n organic electrochemical diodes with organic electrochemical transistors in the front-end pixel of a recording array. This configuration facilitates the access of organic electrochemical transistor output currents within a large network operating in the same electrolyte, while minimizing crosstalk from neighboring elements due to minimized reverse-biased leakage. Furthermore, we use these devices to fabricate time-division-multiplexed amplifier arrays. Lastly, we show that, when fabricated in a shank format, this technology enables the multiplexing of amplified local field potentials directly in the active recording pixel (26-μm diameter) in a minimally invasive form factor with shank cross-sectional dimensions of only 50×8 μm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mu m}^{2}$$\\end{document}.

The influence of onshore harbour layout on coastal sedimentation and erosion at Pekalongan

Pekalongan City is an area that experience floods. Therefore, the government launched program for flood management in the Pekalongan area. The program requires the PPN Pekalongan to be relocated. The construction of the Pekalongan Onshore Harbour will change the hydrodynamics pattern and transport sediments. To overcome this problem, it is necessary to conduct a study of these changes. High current speeds and high waves will cause high sediment transport, but it can have a different impact. The first impact is high erosion, like in the existing condition T3. The second impact is high sedimentation, such as in T1 layout 1. The third impact is experiencing slight erosion or sedimentation at the end of modelling, but fluctuations during the modelling process are very large, such as in T5 layout 2. The bed level change is -313.5 mm, 20.88 mm, and -13.66 mm, respectively. Slow currents with high waves cause large sedimentation such as T4 layout 2 or high erosion such as T2 in existing conditions with bed level changes of 41.53 mm and -332.07 mm, respectively. Layouts 1 and 2 are in accordance with regulations because it has current speeds below 0.4 m/s and wave heights below 0.5 m.

Model-Free Control for Doubly Salient Permanent Magnet-Generator-Based Tidal Stream Turbine Considering Flux-Weakening Operation

Renewable energy generation is increasingly important due to serious energy issues. A Doubly Salient Permanent Magnet Generator (DSPMG) can be an interesting candidate for tidal stream renewable energy systems. However, the special structure makes the system nonlinear and strongly coupled even after Park transformation and involves a larger torque ripple. Previous research mainly focused on model-based control for this machine, which is very sensitive to the parameters. Thus, to control the complex systems stably and accurately, two model-free control algorithms, Active Disturbance Rejection-Based Iterative Learning Control (ADRILC) and Active Disturbance Rejection Control–Iterative Learning Control (ADRC–ILC), are proposed for the current and speed control loops of a DSPMG-based Tidal Stream Turbine (TST), respectively. ADRC–ILC uses ADRC to deal with the external non-periodic speed ripple and adopts ILC to reduce the internal periodic speed ripple. ADRILC employs an iterative method to improve the ESO for the enhancement of the convergence rate of ILC. Considering the variable tidal speed, when the speed is above the rated value, Maximum Power Point Tracking (MPPT) must be changed to a power limitation strategy for limiting the generator power to the rated value and extending the system operating range. Thus, Optimal Tip Speed Ratio (OTSR)-based MPPT (for a low tidal current speed) and Leading Angle Flux-Weakening Control (LAFWC) (for a high tidal current speed) strategies are also proposed. According to the simulation results, the proposed ADRC–ILC + ADRILC has the lowest torque ripple, the highest control accuracy, as well as a good current tracking capability and strong robustness. At the rated speed, the proposed method reduces the torque ripple by more than 20% and the speed error by about 80% compared with PI control: the current difference is limited in 2A. The LAFWC proposed for an excessive tidal current speed is effective in conserving the electromagnetic power and increasing the generator speed.

High-performance flexible UV-photodetector via self-assembled ZnO films

Zinc oxide (ZnO) is one of the most attractive materials for the preparation of ultraviolet photodetectors (UV PDs). However, the high leakage current and slow response speed significantly limit the practical applications of ZnO-based PDs. In this study, the fabrication of UV PDs based on self-assembled ZnO film has been proposed. The device has an ultra-low dark current (25 pA@10 V) and exhibits fast response speed (190 ms/68.6 ms) and high detectivity (1.91 × 1014 Jones) for 360 nm light. The high performance can be attributed to the operating mechanism of ‘light-induced reduction of junction barrier height’. The analysis based on the thermionic emission theory indicates that illumination can significantly reduce both the Schottky barrier height and series resistance of the device. The prepared flexible PD based on the self-assembled film not only maintains excellent detection performance but also has strong durability and mechanical robustness. After 1000 bending-recovery cycles, the flexible device exhibits excellent repeatable on/off photo-switching behaviors. The measured time-response curves of the flexible PD under five different bending states show unaffected photocurrent, demonstrating excellent flexibility and stability.

Analysis of mechanical properties and optimization of tungsten inert gas welding parameters on dissimilar AA6061-T6 and AA7075-T6 by a response surface methodology-based desirability function approach

This study explores the influence of welding current, travel speed and gas flow rate on response parameters including ultimate tensile strength (UTS), percentage elongation (PE), microhardness (MH) and residual stress (RS) using face-centred central composite design (FCCCD). Dissimilar AA6061-T6 and AA7075-T6 plates were welded using an automated tungsten inert gas (TIG) process. Mathematical models were developed to predict the mechanical properties. High welding current or low travel speed enhanced the joint quality but raised residual stresses. At a welding current of 145 A, travel speed of 1.28 mm/s and gas flow rate of 18 l/min, the optimized UTS, PE, MH and RS were predicted to be 167.28 MPa, 10.25%, 69.61 HV and 65.49 MPa, respectively. Confirmation experiments were conducted to verify the model’s practicality. The results indicate that travel speed has the greatest influence on the responses, followed by welding current, while the gas flow rate has the least effect.

Benthic foraminifera as environmental indicators in the lagoon and mangrove environments of Langkawi, Malaysia

Benthic foraminifera are single-celled protists that are highly abundant in marine and marginal environments. They have been successfully used in several monitoring studies elucidating the status of environmental health conditions. The present study examines the foraminiferal distribution in the surface sediments of the Sungai Kilim, within the Kilim Geoforest Park, in Pulau Langkawi, Malaysia. Information provided by benthic foraminifera were associated with geochemical properties, sediment types, and current speed data to characterize the environment. Twenty-eight genera of benthic foraminifera were identified from the surface samples. Elphidium spp. (relative abundance of 13–83%) were the most abundant genus in the mangrove and lagoon environments along the Sungai Kilim. Salinity, water depth, and temperature were the important parameters that determined the foraminiferal distribution. Test abnormalities were observed in Elphidium spp. (<10% of tests) at several stations; a higher quantity of abnormal tests (5–6%) were observed at stations with high current speeds, especially in mangrove areas. The sediment in the study areas did not show severe heavy metal contamination; therefore, the low diversity and test abnormalities were associated with natural stress from environmental conditions. This information provides a baseline for future environmental monitoring to preserve the Sungai Kilim and the Kilim Geoforest Park.

Experimental and numerical modeling of pile-rock breakwater gap arrangement for optimal coastal erosion protection in deltaic coasts

Pile-Rock breakwaters (PRBW) have been constructed as long continuous features in the West Sea of the Mekong Delta. Optimising the gap arrangement and spatial orientation of these continuous breakwaters can result in positive impacts on the velocity field, sediment distribution, and shoreline morphology. In this study, experimental and numerical modelling was performed to investigate the effect of breakwater gaps on bedload sediment transport and nearshore bed morphology. The gap width across various hydrodynamic conditions was found to have a significant impact on bedload sediment transport and nearshore bed morphology. This study found breakwater gaps can result in high current speed and flow due to wave diffraction, which subsequently also accelerates the shoreline and bed erosion process. The gaps also have a positive impact by facilitating sediment supply behind the breakwaters, which enhances the living shoreline. The sediment exchange rate was higher in low water conditions for the emerged breakwater caused by wave circulation stirring up the sediment with higher wave amplitude. During high-water conditions, the results showed a relatively smaller area of sedimentation behind the breakwater. Under high water level conditions, the ability to stir up sediment decreases, resulting in low sediment transport. The findings from this study can be used to optimize the design of pile-rock breakwaters and their performance on the deltaic coast.

Gate-controlled photoresponse improvement in b-AsP/WSe2 heterostructures with type-I band alignment

As a promising two-dimensional (2D) layered material, black arsenic phosphorus (b-AsP) alloys have received growing attention due to their unique properties and their ability for high-performance broadband photodetection. However, high dark current and slow response speed have already become bottlenecks for further development. Manual vertical van der Waals heterojunctions made of different 2D materials offer opportunities to alleviate such bottlenecks in a simple and low-energy way. The rational design of band alignment can facilitate device performance. In this work, we design and achieve a type-I vertically stacked WSe2/b-As0.084P0.916 device, which exhibits a rectification ratio of 102 along with an unusual backward current as low as 10−12 A. As such, this device can function as an ultrasensitive photodetector, which shows excellent photoresponse properties from the visible to near-infrared region (275–850 nm), with a responsivity of 244 A/W, a specific detectivity of 2.27 × 1012 Jones, and a fast response speed of τrise ≈ 5.1 ms and τdecay ≈ 4 ms. Compared to the dark state, the hole mobility under light stimulation is raised more than ten times (from 1.1 to 12.1 cm2 V−1 s−1), which contributes to numerous excited electron–hole pair transfers from WSe2 to b-As0.084P0.916. The responsivity and detectivity increase by 5 and 3 orders of magnitude, respectively, after applying gate voltage, indicating remarkable gate-controlled properties. These results suggest that the WSe2/b-As0.084P0.916 heterostructure is a promising candidate for future electronic and optoelectronic applications.

Experimental Validation of Float Array Tidal Current Measurements in Agate Pass, Washington

Abstract Tidal currents, particularly in narrow channels, can be challenging to characterize due to high current speeds (&gt;1 m s−1), strong spatial gradients, and relatively short synoptic windows. To assess tidal currents in Agate Pass, Washington, we cross evaluated data products from an array of acoustically tracked underwater floats and from acoustic Doppler current profilers (ADCPs) in both station-keeping and drifting modes. While increasingly used in basin-scale science, underwater floats have seen limited use in coastal environments. This study presents the first application of a float array toward small-scale (&lt;1 km), high-resolution (&lt;5 m) measurements of mean currents in energetic tidal channel and utilizes a new prototype float, the μFloat, designed specifically for sampling in dynamic coastal waters. We show that a float array (20 floats) can provide data with similar quality to ADCPs, with measurements of horizontal velocity differing by less than 10% of nominal velocity, except during periods of low flow (0.1 m s−1). Additionally, floats provided measurements of the three-dimensional temperature field, demonstrating their unique ability to simultaneously resolve in situ properties that cannot be remotely observed. Significance Statement The purpose of this research was to validate measurements of tidal currents in a fast-flowing tidal channel using a prototype technology composed of 20 drifting underwater sensors called μFloats (“microFloats”) and five surface buoys against standard devices (acoustic Doppler current profilers). Float measurements matched those from the standard devices within 10% of the mean water speed and simultaneously provided three-dimensional mapping of temperature in the test region. Results demonstrate how moderate numbers of simultaneously deployed μFloats can provide high-resolution sensing capacity that will improve our understanding of physical, chemical, and biological processes in coastal waters.

Palaeoceanographic and hydrodynamic variability for the last 47 kyr in the southern Gulf of Cádiz (Atlantic Moroccan margin): Sedimentary and climatic implications

AbstractX‐ray fluorescence, grain‐size and oxygen and carbon stable isotope measurements of a 33 m long piston core, recovered from the Pen Duick drift located at the foot of the prominent Pen Duick Escarpment (Atlantic Moroccan margin), are combined to decipher past oceanographic conditions. The data indicate that, similar to the northern Gulf of Cádiz, the Azores Front exerts a major control on the palaeoclimatology of the region. Contrasting the northern Gulf of Cádiz, where Mediterranean Outflow Water is the main water mass at similar water depths, the palaeoceanography of the studied area is mostly influenced by the amount of Antarctic Intermediate Water advected from the south. The density contrast between the Antarctic Intermediate Water and the overlying North Atlantic Central Water determined the strength of the prevailing internal tides and corresponding high current speeds, which drastically impacted the sedimentary record. The most notable impact is the presence of a 7.8 kyr condensed section (30.5–22.7 ka bp). The formation of the Pen Duick sediment drift was not just controlled by the strength of the bottom currents and the intensity of the internal tides, but also by the amount of (aeolian) sediment supplied to the region. Although variable, drift‐growth phases seem to mainly occur during colder periods of the last glacial, that is Heinrich and Dansgaard‐Oeschger events during Marine Isotope Stage 3 and late Marine Isotope Stage 2. These periods, characterised by increased aeolian dust supply and higher bottom currents, coincide with a phase of prolific cold‐water coral growth and enhanced coral mound formation as recorded in numerous cores obtained from the southern Gulf of Cádiz. This implies that both records (on and off mound cores) are pivotal to provide the complete picture of the palaeoclimatic and palaeoceanographic conditions in the region.

Detection of shallow and deep conductive zones using direct current resistivity and time-domain electromagnetic methods, west El-Minia, Egypt

Direct current (DC) resistivity and time-domain electromagnetic (TEM) methods were used to distinguish between saturated and dry zones and in an evaluation of groundwater resources in the western desert of Egypt. DC-resistivity method was used to evaluate the shallow section while TEM method was used for the shallow and deep aquifer sections. In the decay (voltage) curves, the last parts of the early stage and the intermediate stage refer to the shallow aquifer while the late stage indicates the deep aquifer. The effect of ramp-off time was studied. The shallow unrecorded depths of the high current diffusion speed and first and last diffusion depths were determined. The resistivity and thickness of surface deposits and loop side length are the prime influences on diffusion, investigation, and shallow unrecorded depths. By combining the two methods, the subsurface layers were classified into eight conductive and resistive zones. The third (15-75.5 O m), sixth (55-124 O m), and seventh (35-54 O m) are high conductively zones that corresponds to the shallow and deep aquifers, respectively. The TEM method delineated the sedimentary basin and the maximum penetration depth was ∼1300 m. The complementary of two methods confirmed that the resistivity method is sensitive to shallow conductive and resistive zones while the TEM method is sensitive to shallow and deep conductive and resistive zones. The TEM method assisted in identifying the shallow unrecorded depths, the effect of ramp-off time, diffusion depths, and the effect of shallow resistive depths on diffusion depths.

Fast‐Charging Solid‐State Lithium Metal Batteries: A Review

Nowadays solid‐state lithium metal batteries (SSLMBs) catch researchers’ attention and are considered as the most promising energy storage devices for their high energy density and safety. However, compared to lithium‐ion batteries (LIBs), the low ionic conductivity in solid‐state electrolytes (SSEs) and poor interface contact between SSEs and electrodes counteract some advantages of SSEs. As a result, SSLMBs show high energy density but low critical current density and slow charging speed. Herein, the recent progress and proposed strategies for fast‐charging SSLMBs are reviewed. In the second part of this review, various strategies for improving SSE performance in fast‐charging batteries are comprehensively highlighted. In the third part, various rational structure design schemes benefitting fast‐charging batteries are discussed. Finally, the development of fast‐charging SSLMBs is concluded and prospected. It is believed that the combination of fast‐charging times and SSLMBs is rather competitive for next‐generation, high energy density, high safety, and high charging rate energy storage devices.

Fast-Response Amorphous Ga₂O₃ Solar-Blind Ultraviolet Photodetectors Tuned by a Polar AlN Template

Gallium oxide (Ga₂O₃) is an emerging semiconductor for advanced optoelectronic applications owing to its suitable bandgap and advantageous electronic characteristics. While amorphous Ga₂O₃ is highly desired for low-cost and large-scale device application, it suffers from high dark current and slow response speed for practical ultraviolet photodetection. Here we integrate a polar aluminum nitride (AlN) template with amorphous Ga₂O₃ to fabricate a fast-response metal semiconductor metal (MSM) photodetector. It is revealed that the carrier transport and device performance strongly depend on the polarization direction of the AlN template. With a downward polarization from an Al-polar AlN layer, the Ga₂O₃ photodetector achieves an optimized performance with a lower dark current of 0.015 nA, a higher photo-to-dark current ratio of 10⁴, a faster response speed of 31 ms and a recovery time of 22 ms. This study demonstrates an effective route of engineering carrier transport via the external spontaneous polarization for fabricating high-performance solar-blind photodetectors.

High Performance Brushless Direct Current Motor Speed Regulator

High Performance Brushless Direct Current Motor Speed Regulator

Fish Assemblages in Seagrass (Zostera marina L.) Meadows and Mussel Reefs (Mytilus edulis): Implications for Coastal Fisheries, Restoration and Marine Spatial Planning

Seagrass meadows and mussel reefs provide favorable habitats for many fish species, but few studies have compared the associated fish assemblages directly and examined the influence of environmental variables. Knowledge of fish assemblages associated with disparate habitats is needed for the conservation of coastal fisheries and marine spatial planning. Catch per unit effort data derived from fyke nets showed similar species richness and diversity in seagrass meadows and mussel reefs, suggesting that both habitats support elevated marine biodiversity of mobile fauna. However, it was shown that fish assemblage structure differed between those habitats, and also fish abundance in seagrass meadows was significantly higher than in mussel reefs by comparing the data with a multivariate extension of Generalized Linear Models (GLM). Furthermore, employing underwater video recordings to compare fish abundances in high and low water current speed mussel reefs with a Generalized Linear Mixed Model with negative binomial distribution, data revealed similar fish abundances (in terms of the MaxN metric) despite the variation in current speed, probably because the mussel formations provide sufficient shelter, even from high water currents. The commercially important species Atlantic cod (G. morhua), however, was significantly more abundant in the low water current mussel reef. Therefore, restoration efforts targeting G. morhua could benefit from restoring low current mussel reefs. Our study provides input for the conservation of coastal recreational and commercial fisheries, habitat restoration and marine spatial planning where certain habitats may be prioritized.