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The increasing use of automation in fishing vessels has improved trawling efficiency while directly affecting the fishing capacity and cost of fishing vessels. Among the various influencing factors, warp tension and warp length can be varied to automatically balance the retraction and release of warp control. We combined the two parameters and independently designed and developed the key equipment for fishing vessels—the warp dynamometer and meter counter—and control software. The accuracy of the warp tension and length measurements was improved. The designed equipment was applied to sea trials under different working conditions, and the test data records were exported. Next, filtered time-domain graphs of the required parameters were plotted through complex Fourier transform, first-order low-pass filtering, and inverse Fourier transform. The results of data processing using various parameters were compared and analysed to determine the variation trends of the parameters and verify the effects of their balance control. The results indicated that using an automatic balance control system that combines warp tension and warp length can be effective for the fishing operation of offshore double-deck trawlers. In addition, first-order low-pass filtering can be used to filter complex warp tension data. This study also determined the relationship between warp tension and experimental parameters such as warp length and ship speed during the release of control. After the balance control of warp tension and warp length, the net mouth area increased by 30.7% and 36.5%, respectively, and the fishing efficiency of the vessel improved considerably.

Floating offshore wind turbines are easily affected by typhoons in the deep sea, which may cause serious damage to their structure. Therefore, it is necessary to study further the dynamic response of wind turbine structures under typhoons. This paper took the 5MW floating offshore wind turbine developed by the National Renewable Energy Laboratory (NREL) as the research object. Based on the motion theory of platforms in waves, a physical model with a scale ratio of 1:120 was established, and a hydraulic cradle was used to simulate the effect of waves on the turbines. The dynamic response characteristics of offshore wind turbines under typhoons are systematically studied. The research results clarified that the turbine structure is mainly affected by wave loads under typhoons, and its motion response reaches its maximum value under the action of extreme wave loads. The research results of this paper can provide reference value for the design of offshore wind turbine structures under typhoons.

Researches were conducted on the laser welding of 3 mm sheet-thickness lap joints of AA5052 with ER4043 filler wires. The effects of laser power on the joint morphology, microstructure, mechanical properties, and corrosion resistance were investigated. The results indicate that both increased heat input and the addition of filler wires make the molten pool more instable, which results in more process pores. Circular pores are observed in the upper part of the weld, while chain-like pores are distributed in the middle of the weld. The highest tensile strength of the weld joint is 192.61 MPa with an elongation of 10.1% at a laser power of 3.5 kW. The microhardness at the center of the weld is approximately 25% higher than the base material, which is probably because the addition of ER4043 filler wires brings more Si element to the weld. Moreover, the weld joints display superior corrosion resistance compared to the base material. These outcomes enhance the understanding of AA5052 laser welding with fillers wire and provide valuable in-sights for engineering applications. [ABSTRACT FROM AUTHOR]

Breeding is an effective method for the varietal development of pineapple. However, due to open pollination, it is necessary to conduct authentic identification of the hybrid offspring. In this study, we identified the authenticity of offspring and analyzed the genetic diversity within the offspring F1 hybrids resulting from crosses between 'Josapine' and 'MD2' by single nucleotide polymorphism (SNP) markers. From the resequencing data, 26 homozygous loci that differentiate between the parents have been identified. Then, genotyping was performed on both the parents and 36 offspring to select SNP markers that are suitable for authentic identification. The genotyping results revealed that 2 sets of SNP primers, namely SNP4010 and SNP22550, successfully identified 395 authentic hybrids out of 451 hybrid offspring. We randomly selected two true hybrids and four pseudohybrids for sequencing validation, and the results have shown that two true hybrids had double peaks with A/G, while pseudohybrids had single peaks with base A or G. Further study showed that the identification based on SNP molecular markers remained consistent with the morphological identification results in the field, with a true hybridization rate of 87.58%. K-means clustering and UPGMA tree analysis revealed that the hybrid offspring could be categorized into two groups. Among them, 68.5% of offspring aggregated with MD2, while 31.95% were grouped with Josapine. The successful application of SNP marker to identify pineapple F1 hybrid populations provides a theoretical foundation and practical reference for the future development of rapid SNP marker-based methods for pineapple hybrid authenticity and purity testing. [ABSTRACT FROM AUTHOR]

In this study, the heave plate of a DeepCwind floating wind turbine platform with a capacity of 5 MW was used as the research object. The influence of the perforated chamfer on the hydrodynamic performance of the heave plate was studied through physical experiments and numerical simulations. Vertical force amplitudes, additional mass coefficients, and damping coefficients were obtained for heave plates with different types of perforations. The results of the numerical simulations and physical experiments revealed that hydrodynamic coefficients changed consistently. During the same period, the damping and additional mass coefficients of the heave plate gradually decreased and increased with an increase in the motion amplitude, respectively. When comparing with different perforation angles, the coefficients initially decrease and then increase with an increase in the perforation angle. In the case of a large perforation angle, the coefficients were higher than those of the conventional heave plate without perforations. [ABSTRACT FROM AUTHOR]