To reduce the current ripples of finite control set model predictive control, this paper proposes a continuous voltage vector model-free predictive current control method for the surface mounted ...permanent magnet synchronous motor (SMPMSM). In the proposed method, the continuous phase and the amplitude of the voltage vector are optimized in a sequence based on their uncoupling feature, and then the steady-state current fluctuation can be reduced. Only six active voltage vectors are enumerated, and the optimal phase is obtained by establishing the Lagrange interpolation polynomial between the cost function and the phase of voltage vectors. Then, the amplitude of the voltage vector with the optimal phase is optimized based on the principle of minimizing the cost function, and the optimal voltage vector is synthesized by a three-vector method. In addition, the ultra-local model of the SMPMSM drive system from the previous study is used to improve the robustness of the proposed method. The current dynamic and steady-state responses are demonstrated through the simulation and experimental results.
This article is based on 183,819 port state control inspections from various port state control regimes and casualties from three different data sources for a time period of 6 years. It is the first ...time an analysis on a combined dataset of this magnitude has been performed. Binary logistic regression is used to measure the effect of inspections on the probability of casualty, which can be measured for very serious casualties but not for serious or less serious casualties. In addition, the magnitude of improvement areas for targeting substandard vessels is determined and the models further show how targeting of substandard ships on a combined dataset can be improved. In addition, the analysis also compares the fishing fleet with the commercial fleet.
As Japan has announced its decision to start discharging radioactive water into the Pacific Ocean, it's expected that global marine environment pollution will worsen due to the contaminated water, ...posing a new challenge to the ballast water management system dominated by the flag state. In this context, this paper studies the equilibrium strategies on ship ballast water discharge controls between the flag states and the port states in different situations. Through a numerical study, we analyze how the ballast water discharge location, decision sequences of relevant states, the role of the International Environmental Protection Organization and its aid strategies impact the control strategies by the flag states and the port states. In the event of radioactive water discharge, the flag state controls alone do not yield satisfactory results, and the port state control is effective supplementation to the flag state control to mitigate risks of marine pollution. Furthermore, where the International Environmental Protection Organization takes reasonable aid steps, the flag states are incentivized to take control measures.
Display omitted
•The challenges of ship ballast water management will be much severer after nuclear water released by Japan.•Supplementary role of Port State Control to Flag State Control in ballast water management is discussed.•The role of International Environmental Protection Organization in ballast water management is discussed.•Policy suggestions are proposed for ballast water management under the background of nuclear water release.
Port State Control (PSC) is the inspection of foreign ships in national ports assists in the removal of substandard ship commerce from the global sea and ensures that no ship poses a threat to ...maritime safety and the marine environment. When a clear ground is discovered during an inspection, the inspector has the authority to detain the ship until the flaws are corrected in order to assure safety and reduce pollution hazards. This paper adopted a traditional literature review method using the selected six (6) years data from the inspections conducted by maritime authorities from 2016 to 2021 and incorporate with qualitative and quantitative analysis to ascertain the influence of each risk factor on the number of arrests, including the relationship between risk factors and the type of detain deficiency, which is a critical part of the study. This study's findings provide important insights into how to facilitate an effective way in selecting the ship to be inspected, followed by identifying the ship's risk profile and designing the inspection area, which plays a critical role in assisting the inspector in terms of time efficient and effective inspection (especially for the ships, which have a short duration at berth) during inspection to further strengthen maritime safety, ship's safety, seafarers' health and marine environmental protection.
Display omitted
•PSC is the inspection of foreign ships in foreign ports to remove substandard ship.•The inspections conducted by maritime authorities from 2016 to 2021 was used.•Analysis to ascertain the influence of each risk factor on the number of arrests.•Study the relationship between risk factors and the type of detain deficiency.
As international regulations on aquatic organism discharge in ships' ballast water take effect, port state authorities will need a sampling device for compliance inspectors to potentially use for ...sample collection. Importantly, the device must be easily operable, quickly connectable to the main ballast water pipe, and reliable in collecting a representative sample of the ballast water flowing through the pipe. Existing sampling devices currently fall short in these aspects. Therefore, we've developed, manufactured, and validated a new sampling skid. This design enables the regulation of flow velocity and flow rate, facilitating the simultaneous, convenient collection of organisms ≥50 μm and other biological samples. In this study, we conducted a comparative analysis of sampling outcomes between traditional net sampling devices, using land-based experiments to assess the accuracy and precision of the innovative sampling skid. The findings show that, despite significant differences in <10 μm organism concentrations, the sampling skid, as an alternative to traditional net and other skid devices, has demonstrated substantial potential and feasibility.
•Development of a stand-alone sampling skid for the collection of living organisms from ballast water.•Field testing of sampling skids on land as a potential substitute for traditional plankton nets.•Comparable collection of >10 μm living organisms samples between sampling skids and plankton nets revealed no significant differences.
•Game model improves NIR, analyzing port and flag states and shipowners’ strategies.•First-time reputation rewards and punishments add shipowner payoffs and flag states.•It is important to ...differentiate flag state performance when punishing or rewarding.•Shipowners care less about their reputations and more about their profits.
Port state control is regarded as the “last safety net” for maintaining maritime safety and environmental pollution prevention standards for foreign ships calling at or anchoring off international ports. Owing to limited resources, port states select and inspect ships that are more likely to be substandard under their inspection regimes and then record and publish the performance of shipowners and flag states. To encourage ships to comply with standards during subsequent inspections and improve new inspection regimes, we develop a game model analysing the strategies of port states, flag states, and shipowners. We then confirm the Nash equilibrium of the pure and mixed strategies. Subsequently, we investigate the influence of different reward and punishment conditions on flag states and shipowners and generate the following three results: first, differentiating flag state performance is crucial for port states to provide appropriate punishments or rewards to improve ship safety; second, reputation rewards have stronger impacts than reputation punishments for flag states; and third, reputation rewards or punishments from port states have little influence on shipowners’ strategies, since shipowners are much more concerned about their profits.
The electron spin configuration was successfully optimized to intermediate spin by interface engineering and plasma treatment.The catalysts with optimized electronic structure have excellent ...electrocatalytic activity for oxygen evolution reaction.
Display omitted
The electrocatalytic activity of transition-metal-based compounds is closely related to the electronic configuration. However, optimizing the surface electron spin state of catalysts remains a challenge. Here, we developed a spin-state and delocalized electron regulation method to optimize oxygen evolution reaction (OER) performance by in-situ growth of NiCo2(OH)x using Oswald ripening and coordinating etching process on MXene and plasma treatment. X-ray absorption spectroscopy, magnetic tests and electron paramagnetic resonance reveal that the coupling of NiCo2(OH)x and MXene can induce remarkable spin-state transition of Co3+ and transition metal ions electron delocalization, plasma treatment further optimizes the 3d orbital structure and delocalized electron density. The unique Jahn-Teller phenomenon can be brought by the intermediate spin state (t2g5eg1) of Co3+, which benefits from the partial electron occupied eg orbitals. This distinct electron configuration (t2g5eg1) with unpaired electrons leads to orbital degeneracy, that the adsorption free energy of intermediate species and conductivity were further optimized. The optimized electrocatalyst exhibits excellent OER activity with an overpotential of 268 mV at 10 mA cm−2. DFT calculations show that plasma treatment can effectively regulate the d-band center of TMs to optimize the adsorption and improve the OER activity. This approach could guide the rational design and discovery of electrocatalysts with ideal electron configurations in the future.
This paper formulates the optimal steady-state regulation (OSSR) problem. In addition to asymptotic stability and regulation, the problem includes a cost on maintaining steady-state inputs and ...outputs to controllers contributing to regulation, contrasting with standard OSS problems that only include a cost on the steady-state inputs and outputs of the plant. Motivated by applications in neuroscience, we develop a two timescale adaptive control architecture to solve a specific instance of the OSSR problem for the case of two control modules: an adaptive internal model and a state feedback. Correctness of the design is proved using two timescale averaging analysis.
