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Fujian Province, located in the southeastern coast of China, has a highly developed coastal marine net cage aquaculture industry. The scale and density of marine aquaculture, especially net cages aquaculture, in China are increasing, which has seriously affected coastal and nearshore environments. Thus, methods for accurately obtaining the area and density of aquaculture net cages hold great significance. Because of the scattered distribution of net cage aquaculture areas, it is difficult to obtain an accurate net cage aquaculture area with traditional remote-sensing extraction methods. Therefore, this paper proposes a method for accurately identifying of the area of aquaculture net cages by combining R3Det single-stage detector and fishnet segmentation technology. A constructed sensing net cage dataset was used for model training and a fishing net segmentation technology was used to segment the remote-sensing image into R3Det testable image. The experimental results showed that the extraction accuracy of this method for round and square net cages was 92.65% and 98.06%, respectively, and the extraction accuracy of the actual net cage culture area was 97.24%. We concluded that the total area of net cage aquaculture in Fujian Province in 2019–2020 was 4363.58 ha, mainly in square net cages. The area of aquaculture was greater in the northern and southern parts of the province and less in the middle. The density of aquaculture was high in the south and low in the north. Compared with traditional remote-sensing extraction methods and neural networks, this solution reduced the impact of similar features on the classification target, realized the application of high-precision, large-area remote-sensing images on the R3Det single-stage detector, and improved the recognition accuracy and the robustness of the model. [ABSTRACT FROM AUTHOR]

In this paper, we design a linearly-polarized dual-wavelength fiber laser used in WDM-ROF-PON, which can achieve wire-line and wireless access synchronously. With polarization multiplexing, the dual-wavelength fiber laser is the union light source of WDM-PON. With the CSRZ-DPSK modulation, the wireless access system of ONU can save RF source and the frequency of radio carrier can be controlled by OLT. The networking has the credible transmission property, including fiber transmission and wireless access. [ABSTRACT FROM AUTHOR]

Interrupted-sampling repeater jamming (ISRJ) is a novel jamming mode for pulse compression radar in principle. In this paper, a jamming approach of applying ISRJ to de-chirping radar is presented. The principles of ISRJ are expounded, and the ways to achieve a train false target for de-chirping radar are analyzed. The characteristics of false target, including time-domain characteristic, frequency-domain characteristic and amplitude characteristic, are described. Based on this, the power requirement for jammer is put forward and the key elements that determine the space distribution location between true and false targets are discussed in detail. At last, simulation results are presented and addressed. This work is beneficial to the jamming design and use of ISRJ. [ABSTRACT FROM AUTHOR]

Holographic gratings in two kinds of photopolymers (PPs) were fabricated by optical interference method. Polyvinylalcohol (PVA) and polyvinylacetate (PVAc) were employed as polymer binders and photopolymerization of acrylamide (AA) was confirmed using infrared spectroscopy. Dynamic behavior of the diffraction efficiency was monitored and its temporal stability at room temperature was also observed. Additionally, the temperature dependence of these gratings was investigated in two PPs. The surface topographical change of the photopolymer layer was observed by atomic force microscope (AFM). [ABSTRACT FROM AUTHOR]

Road extraction is important for road network renewal, intelligent transportation systems and smart cities. This paper proposes an effective method to improve road extraction accuracy and reconstruct the broken road lines caused by ground occlusion. Firstly, an attention mechanism-based convolution neural network is established to enhance feature extraction capability. By highlighting key areas and restraining interference features, the road extraction accuracy is improved. Secondly, for the common broken road problem in the extraction results, a heuristic method based on connected domain analysis is proposed to reconstruct the road. An experiment is carried out on a benchmark dataset to prove the effectiveness of this method, and the result is compared with that of several famous deep learning models including FCN8s, SegNet, U-Net and D-Linknet. The comparison shows that this model increases the IOU value and the F1 score by 3.35–12.8% and 2.41–9.8%, respectively. Additionally, the result proves the proposed method is effective at extracting roads from occluded areas. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is a promising thermal desalination technology, but its application is largely limited by membrane wetting. This study introduces a thin‐film composite (TFC) membrane comprising a polyamide (PA) surface layer, a polydopamine (PDA) interlayer, and a hydrophobic polyvinylidene fluoride (PVDF) membrane substrate for anti‐wetting MD operations. With a PDA reaction time of 1 h, a compact and hydrophilic PDA interlayer forms on the PVDF membrane substrate, facilitating the subsequent formation of the PA surface layer. With 2 cycles of interfacial polymerization process, a dense PA surface layer forms on the PDA interlayer, rendering a TFC membrane with robust wetting resistance. From diffusion experiments and breakthrough pressure measurements, the TFC membrane exhibits excellent wetting resistance because the dense PA surface layer can prevent the wetting contaminants from reaching the hydrophobic membrane substrate due to the combination of the size exclusion effect and capillary effect. The results from this study shed lights on a new approach for the fabrication of robust MD membranes for practical applications. [ABSTRACT FROM AUTHOR]

To address the low sewage collection performance in circular aquaculture tanks, this paper systematically investigates the influence of jet pipe flow rate Q, the deployment distance ratio d/r (where d represents the distance between the midpoint of the axis and the nearest tank wall, and r is the radius of the circular aquaculture tank), the deployment angle θ, and the structure of the jet pipe on the dynamic characteristics of sewage collection. In the field study, a high-definition camera was used to record the distribution of sewage, the distribution of the flow field in the aquaculture tank was measured by the Acoustic Doppler Velocimetry, and the distance between the sewage and the center of the tank was quantified. Furthermore, the sewage collection performance of the aquaculture tank was evaluated by comparing the maximum distance between the sewage and the center of the tank under different working conditions. The results indicated that the formation of an effective horizontal circulation in the circular aquaculture tank is the primary condition for sewage accumulation to the center of the tank, while different flow rate Q of the jet pipe, the deployment distance ratio d/r, the deployment angle θ, and the structure of the jet pipe all can affect the sewage collection effect in the tank. In the horizontal single-pipe single-hole jet pipe structure mode, the best sewage collection result was obtained at the deployment angle θ of 0°, the deployment distance ratio of 1/4, and the deployment flow rate Q of 7 L/s; when the deployment flow rate Q was less than 7 L/s, the sewage accumulated near the tank wall, and the sewage particle dispersion was relatively high. In the vertical single-pipe porous jet pipe structure mode, better sewage collection performance was achieved when the deployment flow rate Q was adjusted to 7 ~ 9 L/s, the deployment angle θ was set to 45°, and the deployment distance ratio d/r was set to 1/4. The sewage collection performance of the aquaculture tank under the vertical single-pipe porous jet pipe deployment mode was obviously better than that of the horizontal single-pipe single-hole jet pipe mode. These results can directly and effectively guide the inlet design of such aquaculture tanks to reduce the flow rate and energy consumption and improve sewage collection performance. [ABSTRACT FROM AUTHOR]

Presents the properties of the upper and lower box-counting dimensions and their geometrical explanations. Differences between the upper and lower box-counting dimension theory; Role played by the upper box-counting in the dimension theory; Stability of the lower box-counting dimension.

Accurately building height estimation from remote sensing imagery is an important and challenging task. However, the existing shadow-based building height estimation methods have large errors due to the complex environment in remote sensing imagery. In this paper, we propose a multi-scene building height estimation method based on shadow in high resolution imagery. First, the shadow of building is classified and described by analyzing the features of building shadow in remote sensing imagery. Second, a variety of shadow-based building height estimation models is established in different scenes. In addition, a method of shadow regularization extraction is proposed, which can solve the problem of mutual adhesion shadows in dense building areas effectively. Finally, we propose a method for shadow length calculation combines with the fish net and the pauta criterion, which means that the large error caused by the complex shape of building shadow can be avoided. Multi-scene areas are selected for experimental analysis to prove the validity of our method. The experiment results show that the accuracy rate is as high as 96% within 2 m of absolute error of our method. In addition, we compared our proposed approach with the existing methods, and the results show that the absolute error of our method are reduced by 1.24 m–3.76 m, which can achieve high-precision estimation of building height. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we design a linearly polarized dual-wavelength fiber laser used in WDM-ROF-PON, which can achieve wire-line and wireless access synchronously. The all-fiber linearly polarized dual-wavelength fiber laser uses a PM chirped FBG and a PM FBG as the resonant cavity mirrors. Due to the PHB, a steady dual-wavelength laser can be realized. With polarization multiplexing, the dual-wavelength fiber laser is the union light source of WDM-PON. With the CSRZ-DPSK modulation, the wireless access system can save RF resource in ONU and the frequency of radio carrier can be controlled by OLT. The networking has the credible transmission property, including wireless access and fiber transmission. [Copyright &y& Elsevier]

The submerged deep-water longline aquaculture facility is known as a typical, flexible multi-degree-of-freedom offshore structure. Effects of layout concepts of the dropper weight, the upper buoy pattern and the incident wave angle on longline aquaculture systems have been studied by means of numerical modellings and conducting scaled model experiments. The results have showed that the dropper weight and the incident wave angle have significant influence on the motion and loading of the raft-like system. The maximum displacement of the main line is negatively correlated with the dropper weight. The maximum tension of the main line, the downstream mooring line, the upper whip lines and the dropper linesincreases with the increase of the dropper weight. The tension of the upstream mooring line decreases slightly with the increase of the dropper weight. The impact of the upper buoy pattern on the motion and loading of the system is so insignificant as to be ignored. The maximum tension of the mooring lines and the displacement of the long line are positively correlated with structure orientation within the angle range of 0 ° to 60 ° and show negative correlation within the structure orientation of 60 ° to 90 °. The impact of structure orientation on the main line, the upper whip lines and the dropper lines is not so obvious. This study is expected to benefit the design and safety assessment of the longline aquaculture facility with similar structures and environment conditions in this study. [ABSTRACT FROM AUTHOR]

The traditional corner reflector is a type of classical passive jamming equipment but with several shortcomings, such as fixed electromagnetic characteristics and a poor response to radar polarization. In this paper, an eight-quadrant corner reflector equipped with an electronically controlled miniaturized active frequency-selective surface (MAFSS) for X band is proposed to obtain better radar characteristics controllability and polarization adaptability. The scattering characteristics of the new eight-quadrant corner reflector for different switchable scattering states (penetration/reflection), frequency and polarization are simulated and analyzed. Results show that the RCS modulation depth, which is jointly affected by the electromagnetic wave frequency and incident directions, can be maintained above 10 dB in the majority of directions, and even larger than 30 dB at the resonant frequency. Moreover, the RCS adjustable bandwidth can be as wide as 1 GHz in different incident directions. [ABSTRACT FROM AUTHOR]

To study the influence of vegetation on shadow extraction, an anti-interference DCNN was developed to extract shadows and vegetation from QuickBird images. The vegetation features, color and geometric information were analyzed qualitatively and quantitatively, and the regression equation of shadow extraction accuracy was obtained. We got that the average brightness value of vegetation in R and G band and the standard deviation of brightness in G band are significantly negatively correlated with the recall rate of shadow extraction, P>0.05;and the standard deviation of the inner edge ratio of vegetation boundary complexity is significantly positively correlated with the recall rate. [ABSTRACT FROM AUTHOR]

Accurate fire ignition spatial location methods can serve the automatic fire suppression based on video. Although current fire detection systems based on monocular surveillance videos can quickly detect fires, it is impossible to obtain the 3D position due to the polysemy of 2D images. To further promote the universal application of automatic fire suppression, we propose a 3D indoor fire ignition location method based on monocular vision. This is the first study on spatial orientation of fire based on monocular vision. First, the indoor scene is quickly reconstructed as the basis of the scene. Second, based on our previous research on fire detection, the refined position of the fire in 2D images and its topological relationship with the space object are analyzed. The hierarchical constraints from 2 to 3D are established for the spatial orientation of the indoor fire ignition point. The experimental results show that the average absolute error is only 4.82 cm and that the average relative error is 1.71%. In addition, our method can be embedded into the existing fire prevention and control system at a low cost, further promoting the development of intelligent fire prevention and control. [ABSTRACT FROM AUTHOR]

As the main component of the anchorage system in marine aquaculture facilities, the anchor pile is key to ensuring safety and stability. However, conventional monopiles have limited capacity to withstand uplift forces, thus rendering them susceptible to deviations and potentially causing damage to facility structures. Hence, a new winged monopile is proposed to improve and optimize the anchor pile. In this study, laboratory experiments are conducted to investigate the effect of load inclination angle (θ = 0°, 30°, 45°, and 60°), wing length (L = 30, 50, and 70 mm), and wing width (W = 10, and 20 mm) on the uplift resistance capacity of anchor piles in silty clay. The results show that: the winged monopile exhibits at least a 15% improvement in uplift performance compared with the conventional monopile (without wings) when the smallest wing plate parameters are selected (W = 10 mm, L = 30 mm). Additionally, the effect of the wing width on the uplift resistance under an oblique load is more evident than that of the wing plate length. As the area of the wing plate increases, the range of improved wing plate efficiency first increases, and then gradually decreases. This study can be used as a reference for the design optimization of uplift piles and the construction of marine aquaculture. [ABSTRACT FROM AUTHOR]

Anchor piles are widely used in marine aquaculture, and the safety is largely determined by the uplift resistance capacity,especially in harsh ocean environments. However, there are few practical guides to the design and installation of the anchor piles for mooring the body of marine aquaculture equipment. Laboratory experiments were conducted to investigate the effect of the initial tension angle, pile diameter, embedded depth, and pile configuration on the uplift resistance capacity of anchor piles under oblique loads. CCD camera and load cell were utilized to measure the corresponding displacement and load, respectively. The results show that increasing the initial tension angle of circular and square single piles can significantly improve the uplift resistance capacity. The failure load of the square single pile was slightly higher than that of the circular single pile. Increasing the pile diameter can effectively improve the failure load and delay the development speed of the pile top displacement. Increasing the embedded depth can effectively improve the failure load and increase the lateral displacement of the pile top. The uplift resistance capacity of the dual anchor piles was better than that of the single anchor piles. The layout configuration has little effect on the failure load, but has a large effect on the displacement development. [ABSTRACT FROM AUTHOR]

With respect to the detection and recognition of an Artificial Modulation Target (AMT) with different modulated types, the state-of-the-art methods generally suffer the deficiencies of overfitting and insufficient generalization of existing neural network solutions. To address these problems, this paper proposes a multi-scale amplitude-phase feature discrimination method for AMTs in SAR images. First, a multi-type modulated AMT Dataset is generated (AMT Detection and Modulation Type Recognition Dataset, ADMTR Dataset), wherein the factors of jamming position, jamming-to-signal ratio (JSR), and the modulated parameter are considered to enhance the generalization. Second, a Multi-Input Multi-Output Fusion Wavelet Neural Network (MIMOFWTNN) is established, which not only uses the amplitude information of the scene but also adequately makes use of the phase and high-frequency information. This empowers us to detect the AMT in a higher dimensional feature space such that the type recognition can be implemented with more certainty. Analysis and discussions conducted on comparison experiments and ablation experiments demonstrate that the proposed network can achieve an average accuracy of 96.96% on the cross-validation set and a correct rate of 99.0% on the completely independent test set, which outperforms the compared methods. [ABSTRACT FROM AUTHOR]

Reconfigurable metasurfaces have shown unprecedented capabilities in controlling electromagnetic (EM) waves in recent years and play an essential role in information manipulation. However, most research on reconfigurable metasurfaces is limited to planar rigid structures, with only one control function and suitable for specific single polarization. Achieving simultaneous control of phase, polarization, and frequency in the conformal structure has significant practical implications in many applications, but remains obviously challenging. In this paper, a flexible multifunctional time‐varying phase‐modulated metasurface (MTPM) with orthogonal polarization control is proposed for conformal applications to manipulate the spectrum distribution. It enables time encoding capability in controlling the phase characteristics of x‐ and y‐polarized EM waves individually by switching the bias voltage of the PIN diode in two directions. Discrete harmonic spectrum and continuous Doppler frequency shifts are implemented separately on two orthogonal polarizations by applying different time coding sequences. As a practical application, a conformal MTPM for radar feature transformation is explored. Multiple discrete false targets and defocusing phenomena can be realized respectively for x‐ and y‐polarized waves. Both simulated and measured results verify the validity of the proposed method and prototype. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the effects of temperature and dissolved oxygen on juvenile largemouth bass during transportation. The experiment involved four temperature groups: 20, 15, 10, and 5 °C. We analyzed the effects of acute and uniform cooling on fish behavior to determine the optimal approach for cooling. Then, we simulated transport under different temperature conditions while measuring the dissolved oxygen level and metabolic rate until all the fish died. The results showed that acute cooling significantly influenced the tail-beat frequency of fish compared with uniform cooling, while abnormal behaviors such as increased swimming, attempted jumping out of the water, and loss of balance were observed. As the transport temperature reduced, the oxygen consumption rate of fish significantly changed at 10 °C, being 2.6 times lower than at 15 °C, with values of 0.10 ± 0.02 and 0.47 ± 0.07 mg·g−1·h−1, respectively. The critical oxygen threshold (Pcrit) of fish were 1.90 ± 0.12, 1.61 ± 0.04, 1.15 ± 0.09, and 1.12 ± 0.25 mg·L−1 at 5, 10, 15, and 20 °C. In addition, below Pcrit, hypoxia-led behavior changes and oxygen consumption rate reduction were observed at every transport temperature. The findings suggest that the optimal low temperature can reduce metabolism and improve the hypoxia tolerance of juvenile largemouth bass. We recommend transporting largemouth bass at an optimal low temperature (15 °C), monitoring fish behavior, and maintaining oxygen levels above Pcrit during transport to prevent stress. [ABSTRACT FROM AUTHOR]

• The maximum noise ratio kurtosis product deconvolution is proposed. • A new index noise ratio kurtosis product is proposed as the objective function of the deconvolution. • The new index signal envelope cycle kurtosis is designed to estimate the failure period of vibration signal. • The filter coefficients are converted into angular parameters, and the filter is optimized with artificial rabbit optimization. The weak signal changes caused by early bearing failures and complex transmission path attenuation result in low signal-to-noise ratio of vibration status signals, which makes it difficult to effectively extract faults features. Blind deconvolution methods have excellent performance in fault impulses extraction. The factors affecting performance of deconvolution include selection of objective function, periodicity detection, and method of finding the optimal filter. To better solve these three problems, maximum noise ratio kurtosis product deconvolution (MNRKPD) is proposed. In this method, the maximization of noise ratio kurtosis product (NRKP) is proposed as objective function, and signal envelope cycle kurtosis (SECK) is constructed to estimate fault period. Artificial rabbits optimization (ARO) is applied to find optimal filter. The effectiveness of MNRKPD is verified by simulations and experimental validations. Compared with traditional deconvolution methods shows that MNRKPD can overcome strong noise and harmonic effect effectively and can extract periodic fault impulses more effectively. [ABSTRACT FROM AUTHOR]

China's railway construction is rapidly transitioning toward integrated management of "stakeholders, management elements, and management processes". Therefore, comprehensive and whole‐process digital twin scene modeling is urgently needed for intelligent railway construction. However, the requirements of three‐dimensional scenes in different stages vary hierarchically, resulting in a lack of construction semantics and limited universality in modeling. This article proposes a knowledge‐guided digital twin modeling method of hierarchical scenes for a high‐speed railway. We first build a knowledge graph of "knowledge‐model‐data" to achieve an accurate and hierarchical description of railway scenes. We then establish a parameter‐driven modeling method that integrates knowledge guidance and primitive combination to generate a display scene and a virtual design scene automatically. Third, we propose joint linkage and model growth methods for construction action modeling, which are used to generate a virtual construction scene. Finally, in response to the hierarchical scene‐generating requirements in different stages, we conduct intelligent modeling experiments for the entire design and construction process. The knowledge graph of the hierarchical semantic description mode significantly improves the flexibility and universality of the modeling method. The proposed modeling method for the entire process contributes to the rapid representation of design data, in‐depth design, visual exploration, and dynamic optimization of the construction process. This article provides a reliable digital twin modeling solution for the entire process to improve design and construction quality. [ABSTRACT FROM AUTHOR]

Reasonable regulation of stocking density enables aquaculture tanks to achieve excellent self-cleaning performance, which plays a crucial role in the healthy growth and overall welfare of fish. Enhancing the waste collection, and removal capacity and improving the hydrodynamic characteristics in these tanks are pressing issues in the development of recirculating aquaculture systems (RAS) toward sustainable aquaculture. This study investigates the impact of fish (largemouth bass) stocking density (3, 6, and 9 kg/m3) on the self-cleaning performance of circular aquaculture tanks under single- and dual-inlet modes through experiments. The effects of stocking density and fish behavior on the hydrodynamic characteristics of the tanks were analyzed using the average velocity v avg , drag coefficient C t , and turbulence intensity root mean square (RMS). Finally, the sensitivity analysis method was adopted to quantify the sensitivity (S) of RMS to changes in stocking density and inflow rate under two different water-inlet modes. This allows the comparison of the comprehensive impacts of stocking density and inflow rate on the self-cleaning performance of culture tanks. The results indicate that under a single-inlet mode, adjusting Q = 8 L/min and ρ = 9 kg/m3 maximizes the self-cleaning performance of the tank compared with fishless conditions, with waste collection efficiency increasing by approximately 4.3 times, under a dual-inlet mode, adjusting Q = 10 L/min and ρ = 9 kg/m3 results in the greatest enhancement in self-cleaning performance relative to fishless conditions, with an increase in waste collection efficiency of approximately 3.44 times. In both single- and dual-inlet modes, when the stocking density increases from 0 to 9 kg/m3, the RMS values increase by a maximum of approximately 2.3 and 1.2 times, respectively. Furthermore, when 6 kg/m3 < ρ < 9 kg/m3 and 8 L/min < Q < 10 L/min, the RMS is more sensitive to changes in stocking density under a single-inlet mode and is more sensitive to changes in inflow rate under a dual-inlet mode. The findings can offer guidance on the optimal stocking densities for aquaculture tanks to obtain superior self-cleaning performance, and contribute to the practical management of RAS. • Clarified how stocking densities of largemouth bass affect self-cleaning performance in circular tanks with single and dual inlets. • Visualized and compared the impact of fish behavior on tank self-cleaning performance. • Innovatively applied a sensitivity analysis method for comprehensive analysis of stocking density and inflow rate. [ABSTRACT FROM AUTHOR]

In this study, a six-degree-of-freedom (6-DOF) motion platform is utilized to simulate the transverse rolling motion of aquaculture tanks aboard deep-sea aquaculture vessels. It examines the effects of different inlet configurations (single and four-pipe inlet), rolling motions (amplitude Θ and period T), and inlet pipe jet angles α (the acute angle between the jet direction of the inlet pipe and the inclined wall to which it is connected) on the self-cleaning capabilities and flow field characteristics of the aquaculture tank. The findings indicate that the waste collection time in the tank is affected by the combined influences of rolling amplitude and period. In the single-pipe inlet configuration, waste collection time increases with the rolling period and initially increases, then decreases with the rolling amplitude. In the four-pipe inlet configuration, waste collection time increases with the rolling period and decreases with the rolling amplitude. Optimal waste collection performance is achieved at α = 45° in both configurations. Regarding flow field characteristics, variations in rolling period and amplitude significantly alter the flow field within the aquaculture tank. In both configurations, as the period decreases and the amplitude increases, the high-velocity regions and the central vortex area within the tank expand, and the average flow velocity of the water also rises. This corresponds to a reduction in waste collection time and an increase in the waste collection rate. In both configurations, the Flow field is most uniform at α = 45°, which corresponds to the highest waste collection capabilities among all jet angles. The results indicate that while decreasing the rolling period and increasing the amplitude can enhance the self-cleaning capabilities, they also lead to excessively rapid water flow velocities. In practical applications, it is important to select appropriate farming areas based on fish suitability and to choose the correct inlet jet angles for different numbers of inlets. The findings can provide theoretical support and a scientific basis for optimizing the flow characteristics and self-cleaning performance of aquaculture vessels under rolling motion and contribute positively to the advancement of deep-sea aquaculture technology. • The effects of rolling motions on the self-cleaning ability of aquaculture tanks during mooring have been clarified. • A systematic analysis of self-cleaning ability under two inlet configurations and optimal jet angles under rolling motion. • Using PIV technology, we measured the flow field and analyzed flow velocity characteristics with PDF and CDF. [ABSTRACT FROM AUTHOR]

In recent years, the development of China's marine aquaculture has brought serious challenges to the marine ecological environment. Therefore, it is significant to classify and extract the aquaculture zone and spatial distribution in order to provide a reference for aquaculture management. However, considering the complex marine aquaculture environment, it is difficult for traditional remote sensing technology and deep learning to achieve a breakthrough in the extraction of large-scale aquaculture zones so far. This study proposes a method based on the combination of piecewise linear stretching and R3Det to classify and extract raft aquaculture and cage aquaculture zones. The grayscale value is changed by piecewise linear stretching to reduce the influence of complex aquaculture backgrounds on the extraction accuracy, to effectively highlight the appearance characteristics of the aquaculture zone, and to improve the image contrast. On this basis, the aquaculture zone is classified and extracted by R3Det. Taking the aquaculture zone of Sansha Bay as the research object, the experimental results showed that the accuracy of R3Det in extracting the number of raft aquaculture and cage aquaculture zones was 98.91% and 97.21%, respectively, and the extraction precision of the area of the aquaculture zone reached 92.08%. The proposed method can classify and extract large-scale marine aquaculture zones more simply and efficiently than common remote sensing techniques. [ABSTRACT FROM AUTHOR]

Accurate and rapid human detection is crucial for emergency rescue in indoor fire scenarios, and surveillance video provides more possibilities for this work. However, smoke from fires reduces the visibility of humans in surveillance videos, which weakens the expression of human characteristics and makes it difficult to detect humans. To the best of our knowledge, existing studies do not include detecting human in smoke. However, human rescue often occurs in smoke scenarios in real-world settings. We introduce a new problem for human detection in this paper and propose an experimental investigation based on an enhanced relation-aware global–local attention network for escaping human detection in indoor smoke scenarios. First, we address the relationship of humans in smoke scenarios between the global body and local part based on a relation-aware global–local attention module, which can solve the problem of human disturbance by flowing smoke. Second, a prediction architecture considering interference is built to address human escape postures and video scales to obtain better human detection results. In addition, our method considers a faster frame rate for effective deployment. Finally, we propose a data simulation strategy for escaping humans in indoor smoke scenarios and establish a human detection dataset to prove the validity of our method. Accuracy and speed are used as evaluation criteria for the two testing datasets. Experimental results show that it is feasible and effective for human detection in smoke scenarios. [ABSTRACT FROM AUTHOR]

A rapid and accurate method is presented to determine CaCO3, SiO2, Fe2O3, and Al2O3 in cement raw meal using near-infrared (NIR) spectroscopy. Multiplicative scatter correction (MSC) was employed to eliminate the scattering signal and partial least squares (PLS) regression was used to build the analysis model. The results demonstrated good performance by this approach for the determination of CaCO3, SiO2, Fe2O3, and Al2O3. NIR spectroscopy exhibits the feasibility to characterize the quality of cement raw meal. Compared with prompt gamma neutron activation analysis (PGNAA) and X-ray fluorescence (XRF), this method is more efficient and safer. [ABSTRACT FROM AUTHOR]

Large yellow croaker cultured in cages often face overwintering challenges, which have led to significant economic losses in aquaculture. In natural sea areas, apart from low temperatures, sea current is an important factor affecting the overwintering of large yellow croaker. Therefore, we have set up cages with different mesh sizes to investigate the impact of sea currents on the overwintering of large yellow croaker. Three cages with different mesh sizes (0.5 cm, 1.0 cm, and 2.0 cm) were constructed, and 500 fish were placed in each cage. The group with the 0.5-cm mesh served as the control, while the other two groups were experimental (T1 and T2). Water temperature was monitored daily, and water flow rate was measured at the highest tide point of each month (The first and fifteenth days of the lunar calendar). The experiment lasted for 78 days, during which the body weights and lengths of the fish were measured. Muscle samples were taken for body composition analysis, and liver tissues from control and T2 were collected for transcriptome and metabolome analyses. The water temperature ranged from 8.5 to 12.5 °C during the experimental period. The average sea current velocities in the three groups were 0.049 m/s, 0.167 m/s, and 0.286 m/s, respectively. The survival rates of fish in the control, T1 and T2 groups were 85.25%, 80.66%, and 70.32%, respectively. The weight and condition factor decreased significantly in all groups, with the T2 group experiencing the greatest decline. The lipid and protein contents of the fish in the T2 group were significantly lower than those in the control and T1 groups. Transcriptome analysis showed that the insulin and FoxO pathways were related to the regulation of glycolysis/gluconeogenesis. The PPAR signaling pathway was related to the regulation of lipid metabolism. Metabolome analysis revealed 663 significantly different metabolites in the two groups, of which 10 were significantly downregulated and 51 were significantly upregulated. The combined analysis of transcriptome and metabolome showed that both metabolites and genes involved in the ABC transporter pathway were significantly differentially expressed. The results of the study indicated that fish in high flow rate cages require more fat and protein to provide energy. The insulin and PPAR pathways played important roles in regulating glucose and lipid metabolism. The ABC transporter pathway may play important roles in the transport of small molecule substances and participate in energy metabolism during low-temperature activity in large yellow croaker. [Display omitted] • Sea current affected the survival rate of cage-cultured overwintering L. crocea. • Weight and condition factor of L.crocea in high flow rate cages declined severely. • L.crocea in high flow rate cages consume more fat and protein to provide energy. • PPAR, insulin and FoxO pathways play key roles in metabolism during overwintering. • ABC transporter pathway plays key role in transporting small molecule metabolites. [ABSTRACT FROM AUTHOR]

Indoor fire detection is a challenging task and plays a key role in disaster management. The early stage of a fire is the best stage to extinguish the fire. However, early detection of indoor fires is difficult because the early stages of fires are easily occluded in complex indoor environments. Therefore, a method based on firelight reflection characteristics is proposed for early fire detection in occluded indoor environments. First, the characteristics of fires occluded by complex environments are described by analyzing the characteristics of firelight reflection. Second, a highly sensitive method for foreground recognition is developed through use of strategic background updates and a block binarization threshold, which are suitable for detecting the weak changes caused by occluded fires in videos. Finally, a multiexpert system is established for occluded fire detection by extracting the changing characteristics of the area in which the firelight reflection occurs, including spectral variability, motion persistence, and regional expansion. The accuracy and run time of the system are evaluated based on a large dataset to verify our method. Moreover, our proposed approach is discussed in detail in terms of effectiveness and applicability, and the results show that our method can be effectively applied in indoor occluded fire detection. [ABSTRACT FROM AUTHOR]

• NIR spectroscopy was used for compositional analysis of cement raw meal. • The proposed method takes only 3–5 min for each measurement. • NIR spectra were correlated with oxides content by establishing siPLS models. • The established models were optimized by using different preprocessing methods. Near infrared (NIR) diffuse reflectance spectroscopy, combined with chemometrics techniques was proposed as a fast and accurate method applied for determination of main components (CaO, SiO 2 , Al 2 O 3 , Fe 2 O 3) in cement raw meal. The analyses were implemented by correlation of NIR spectra with reference method made by X-ray Fluorescence (XRF), using different regression methods such as partial least square (PLS), interval PLS (iPLS) and synergy interval PLS (siPLS) with multiple pretreatment methods. The optimal models obtained by using siPLS algorithm showed root-mean-square-error-of-prediction (RMSEP) from 0.0379 to 0.1715, the correlation coefficient (R p) from 0.7294 to 0.9304 and average prediction error from 0.03% to 0.13%. The proposed method is cheaper and safer, and it takes much less time (3–5 min) than the XRF method (40–60 min) for each measurement. Our results demonstrate that NIR diffuse reflectance spectroscopy technology can be applied to quantitative determination of the four oxides in cement raw meal. [ABSTRACT FROM AUTHOR]

Determining oxides content in cement raw meal with near infrared (NIR) spectroscopy, associated with partial least square (PLS) regression, is fast and potential for cement industry to realize cement raw material proportioning control. However, it has hardly been studied. Backward interval PLS (biPLS) with genetic algorithm (GA-biPLS) were applied to select characteristic variables closely related to the concentration of oxide of interest to establish calibration model. The optimal GA-biPLS models showed that the determination coefficient (R p 2) and root mean square error of prediction (RMSEP) were 0.8857 and 0.0994 for CaO, 0.8718 and 0.1044 for SiO 2 , 0.7417 and 0.0693 for Al 2 O 3 , 0.5404 and 0.0387 for Fe 2 O 3 , correspondingly. These results indicate that GA-biPLS can select less variables with better prediction performance by comparison with PLS and biPLS, the NIR spectroscopy combined with GA-biPLS algorithm is a fast, accurate and reliable alternative method for determination of oxides content in cement raw meal. Unlabelled Image • Near infrared spectroscopy was applied for component analysis of cement raw meal. • NIR analysis takes only 3 to 5 min per sample, much less than XRF. • Backward interval PLS with genetic algorithm was proposed for variable selection. • GA-biPLS models with less variables and better accuracy were established. [ABSTRACT FROM AUTHOR]

Although membrane distillation (MD) has been identified as a promising technology to treat hypersaline wastewaters, its practical applications face two prominent challenges: membrane wetting and fouling. Herein, we report a facile and scalable approach for fabricating a Janus MD membrane comprising a dense polyvinyl alcohol (PVA) surface layer and a hydrophobic polyvinylidene fluoride (PVDF) membrane substrate. By testing the Janus membrane in direct contact MD experiments using feeds containing a sodium dodecyl sulfate (SDS) surfactant or/and mineral oil, we demonstrated that the dense Janus membrane can simultaneously resist wetting and fouling. This method represents the simplest approach to date for fabricating MD membranes with simultaneous wetting and fouling resistance. Importantly, we also unveil the mechanism of wetting resistance by measuring the breakthrough pressure and surfactant permeation (through the PVA layer) and found that wetting resistance imparted by a dense hydrophilic layer is attributable to capillary pressure. This new insight will potentially change the paradigm of fabricating wetting-resistant membranes and enable robust applications of MD and other membrane contactor processes facing challenges of pore wetting or/and membrane fouling.

Minimum and zero liquid discharge (MLD/ZLD) are emerging brine management strategies that attract heightened attention. Although conventional reverse osmosis (RO) can improve the energy efficiency of MLD/ZLD processes, its application is limited by the maximum hydraulic pressure (Δ P max ) that can be applied in current membrane modules. To overcome such limitation, novel RO-based technologies, including osmotically assisted RO (OARO) and low-salt-rejection RO (LSRRO), have been proposed. Herein, we utilize process modeling to systematically compare the energy consumption of OARO and LSRRO for MLD/ZLD applications. Our modeling results show that the specific energy consumption (SEC) of LSRRO is lower (by up to ∼30%) than that of OARO for concentrating moderately saline feed waters (<∼35,000 mg/L TDS) to meet MLD/ZLD goals, whereas the SEC of OARO is lower (by up to ∼40%) than that of LSSRO for concentrating higher salinity feed waters (>∼70,000 mg/L TDS). However, by implementing more stages and/or an elevated Δ P max , LSRRO has the potential to outperform OARO energetically for treating high-salinity feed waters. Notably, the SEC of both OARO and LSRRO could be 50% lower than that of mechanical vapor compressor, the commonly used brine concentrator in MLD/ZLD applications. We conclude with a discussion on the practicability of OARO and LSRRO based on membrane module availability and capital cost, suggesting that LSRRO could potentially be more feasible than OARO.

The highly enhanced local electromagnetic field occurring through nanometer gap between the plamonic nanostructures provides the dominant contribution in surface enhancement Raman scattering (SERS) enhancement. Thence, we designed the remarkable SERS platform (AuNPs/WS 2 @AuNPs hybrids) by introducing bilayer WS 2 film as the precise nanospacer. Bilayer WS 2 film can realize the facile and tight combination with AuNPs via the thermal decomposition approach. Dense three-dimension (3D) hot spots provided by this hybrid plasmonic nanostructures are responsible for the extremely satisfying SERS performances. Using rhodamine 6G (R6G) as the probe molecules, the AuNPs/WS 2 @AuNPs hybrids perform the excellent sensitivity with the minimum detectable concentration as low as 10 -11 M. Uniform and reproducible SERS signals illustrate that the synthesized SERS hybrids perform the splendid spot-to-spot reproducibility (RSD~5.4%) and substrate-to-substrate reproducibility (RSD~5.7%). The stability of AuNPs and the protection of WS 2 film endow this hybrid plasmonic nanostructures with the brilliant anti-oxidation stability. Moreover, the enhanced electric field distribution simulated with the COMSOL software proves the remarkable SERS performance in theory. Therefore, AuNPs/WS 2 @AuNPs substrate not only widens the SERS research filed of WS 2 , but also shows vast potential as excellent SERS sensor for practical applicability.

One-dimensional (1D) nanofibers have been considered to be important building blocks for nano-electronics due to their superior physical and chemical properties. In this report, high-performance zinc tin oxide (ZnSnO) nanofibers with various composition ratios were prepared by electrospinning. The surface morphology, crystallinity, grain size distribution, and chemical composition of the nanofibers were investigated. Meanwhile, field-effect transistors (FETs) based on ZnSnO nanofiber networks (NFNs) with various composition ratios were integrated and investigated. For optimized Zn0.3Sn0.7O NFNs FETs, the device based on an SiO2 dielectric exhibited a high electrical performance, including a high on/off current ratio (Ion/off) of 2 × 107 and a field-effect mobility (μFE) of 0.17 cm2 V-1 s-1. When a high-permittivity (κ) ZrOx thin film was employed as the dielectric in Zn0.3Sn0.7O NFNs FETs, the operating voltage was substantially reduced and a high μFE of 7.8 cm2 V-1 s-1 was achieved. These results indicate that the Zn0.3Sn0.7O NFNs/ZrOx FETs exhibit great potency in low-cost and low-voltage devices.