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Berthing is one of the most dangerous phases in the process of ship navigation, and its risk assessment is crucial for both ship safety and port scheduling. To effectively enhance the safety and reliability of the berthing process, a berthing risk assessment method based on the synergy of "human-ship-environment" has been established. First, the impact of the human, ship, and environmental factors on berthing risk was analyzed, and a risk assessment index system for ship berthing was constructed. Then, the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE) methods were employed for a comprehensive risk assessment. AHP was used to determine the weight of each factor reasonably, while FCE was applied for the evaluation of the berthing risk. Finally, the proposed method was applied to evaluate the berthing operations of two ships, namely the KCS ship type and the S-175 large passenger ship type, at the Qingdao Intelligent Ship Testing Field, China. The experiment's results indicate that the evaluation results of the method proposed here have good consistency with the expert survey method. [ABSTRACT FROM AUTHOR]

This paper proposes a calculation method for the optimal solution of the inverse kinematics of redundant robots. Specifically, eight sets of vector solutions of redundant robots are solved by the D-H parameter method. Then, an objective function is designed to measure the accuracy of the robot's inverse kinematics solution and the smoothness of the robot's joint motion. By adjusting the weights of each item, the optimal solution that meets different requirements can be selected. In addition, this paper also introduces an improved artificial potential field method to solve the problem of discontinuous changes in gravitational potential in path planning and the problem of excessive joint torque caused by excessive gravitational potential. Finally, the application of the rapidly exploring random tree (RRT) algorithm in robot path planning and obstacle avoidance is introduced. The above-mentioned calculation method and path planning algorithm were verified in the joint simulation environment of MATLAB Robot Toolbox and CoppeliaSim. The proposed inverse solution method is compared with the inverse solution generated in the CoppeliaSim simulation environment, and the angle error of each joint is less than 0.01 rad. [ABSTRACT FROM AUTHOR]

A risk-aware scheduling method of multienergy virtual power plant (MEVPP) is proposed to measure the uncertainty in MEVPP. First, a novel day-ahead uncertainty scenario generation method based on denoising diffusion probabilistic model is proposed, and historical data are employed to learn the error relationship between real power curves and predict power curves. The probability distribution of the prediction error which describes the day-ahead output power curve of renewable energy source is learned by parameter training. Subsequently, the effect of risk aversion on decision-making is investigated by implementing conditional value-at-risk in the optimization model, MEVPP operation mode under the carbon trading and green certificate trading mechanism is analyzed. Finally, the proposed scheme is implemented on a test MEVPP with carbon trading, and green certificate trading is addressed in detail through a numerical study. Moreover, the effects of the operator's risk-averse behavior on the MEVPP are investigated. [ABSTRACT FROM AUTHOR]

The mechanical response of the marine reef sand–geogrid (RG) interface can be influenced by a high-temperature climate, grain size, and variable stress environments. These factors are critical to the effectiveness of geogrid reinforcement in reef sand engineering. However, there are few studies on the influences of grain size, temperature, and stress history on the mechanical characteristics of RG interfaces, with most studies centering on the influence of single factors on the mechanical characteristics of RG interfaces. In this paper, based on self-developed temperature-controlled large interface shear equipment, a series of before/post-cyclic shear tests were carried out on RG interfaces in the temperature range of 5–80 °C. The impact of different reef sand grain sizes on the RG interface was explored (S1: 1–2 mm; S2: 2–4 mm). It was shown that temperature and grain size had significant influences on the mechanical characteristics of the RS interface. Compared with the S1 RG interfaces, the S2 RG interfaces had higher sensitivity to temperature changes with respect to the before/post-cyclic maximum shear strength. Moreover, in comparison to the before-cyclic shear strength, the post-cyclic maximum shear strength is more responsive to temperature changes. The before/post-cyclic maximum shear strength of the S2 RG interfaces was greater than the maximum shear strength of the S1 RG interfaces as the temperature changed. Based on the results of physical tests, a machine learning model containing 450 datasets was constructed, which can accurately predict the shear strength of the RG interface. [ABSTRACT FROM AUTHOR]

This article proposes a film-linked electrostatic self-assembly microfluidic chip for the first time, designed to be ready-to-use. Barrier films are used to isolate the gas/liquid path microchannels and the pre-stored reagents of the chip before use. Through the linkage design between the film materials, the motion of barrier films is linked to the structural changes inside the chip. Under the combined action of the rebound force of the elastic substrate, the electrostatic adsorption force between the substrates, and the reaction force of the elastic film, the elastic substrate and the liquid storage substrate are instantly bonded, and the self-assembly of the chip is completed within 1 s. By using six independently output programmable sequences to perform the sequential quantitative pumping of pre-stored reagents, the transfer and mixing of samples and pre-stored reagents are automatically driven in a confined space, which greatly reduces the contamination risk and loss rate of samples/reagents, and improves the accuracy and reproducibility of test results. In addition, the microfluidic multi-step reaction driven in parallel can avoid liquid reflux, accurately control the amount of reactant transfer, and realize the quantitative detection of samples. Multiple reactions can be performed synchronously without interference, saving the test time. Since each gas path is independently controllable, the chip can be extended to a variety of biochemical reactions and has the potential to detect a variety of substances. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is essential in regulating plant growth and biomass allocation. Plant N uptake and assimilation influence species adaptation and distribution, yet intra-specific comparisons across environmental gradients are scarce. In this study, white birch (Betula platyphylla) seedlings from three Chinese provenances spanning a wide latitude and temperature gradient were cultivated with two inorganic (NO3 and NH4) and one organic (glycine) N forms. We evaluated seedling performance and N uptake for each N form, including the seedling's ability to uptake intact glycine using stable isotopes (13C and 15N). Our data show that both organic (glycine) and inorganic (NO3−) fertilization forms significantly promoted seedling growth and increased the concentration of N, potassium (K) and phosphorus (P) in plant tissues. However, NH4+ caused toxicity, evidenced by chlorosis and necrosis in the apex of old leaves, thereby limiting growth. Seedling growth increased with decreasing latitude, while nutrient concentrations in both shoots and roots decreased with decreasing latitude. Counter to traditional mineral nutrition theory, all seedlings took up intact glycine. Our study can help guide nursery fertilization practices and suggests that the climate of origin affects growth but does not substantially change the preferred N source. [ABSTRACT FROM AUTHOR]