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Wave radiation stress is the main driving force of wave-induced near-shore currents. It is directly related to the hydrodynamic characteristics of near-shore current whether the calculation of wave radiation stress is accurate or not. Irregular waves are more capable of reacting wave motion in the ocean compared to regular waves. Therefore, the calculation of the radiation stress under irregular waves will be more able to reflect the wave driving force in the actual near-shore current. Exact solution and approximate solution of the irregular wave radiation stress are derived in this paper and the two kinds of calculation methods are compared. On the basis of this, the experimental results are used to further verify the calculation of wave energy in the approximate calculation method. The results show that the approximate calculation method of irregular wave radiation stress has a good accuracy under the condition of narrow-band spectrum, which can save a lot of computing time, and thus improve the efficiency of calculation. However, the exact calculation method can more accurately reflect the fluctuation of radiation stress at each moment and each location.

In this paper, DNVGL’s SESAM software system is used to directly calculate the fatigue strength of typical structural nodes of truss-floating box aquaculture vessels based on fatigue spectrum analysis. According to the three-dimensional potential flow theory, the hydrodynamic analysis of typical working conditions of the ship type was carried out, and the short-term distribution of stress response transfer function, stress response spectrum and stress range under culture conditions was obtained. The load is applied to the ship-wide finite element model to obtain the fatigue strength stress values of typical thermal stress points, and then the fatigue life is estimated by spectral analysis. The research results can provide useful reference and reference for the design and verification stage of the ship type.

Purpose: To evaluate the alterations in macular superficial retinal vessels density and relation with visual acuity in thyroid associated ophthalmopathy (TAO) patients with different severity levels.Method: This cross-sectional observational study included 70 TAO patients and 70 healthy controls. Only the data from the right eyes were analyzed. TAO patients were divided into 7 subgroups according to the NOSPECS score grading from 0 to 6 with 10 cases in each subgroup. Foveal avascular zone (FAZ), vascular density (VD) and perfusion density (PD) of macular 1mm diameter and 6mm diameter areas were measured by optical coherence tomography angiography (OCTA). Results: In TAO patients, significant increases were found in macular and foveal vascular densities (FVD) and perfusion densities (FPD) while significant decrease was found in FAZ area when comparing with control group (pConclusion: Superficial macular blood flow in TAO patients showed an overall increase comparing with healthy controls and a decrease as TAO disease severity worsen. Superficial macular blood flow density was negatively correlated with BCVA.

Background To evaluate the changes in macular superficial retinal vessel density and their relation with visual acuity in thyroid-associated ophthalmopathy (TAO) patients with different severity. Methods This cross-sectional observational study included 70 TAO patients and 70 healthy controls. Only data from the right eyes were analyzed. TAO patients were divided into 7 subgroups according to the NOSPECS score. Foveal avascular zone (FAZ), vascular density (VD), and perfusion density (PD) of macular 1 mm diameter and 6 mm diameter areas were measured by optical coherence tomography angiography (OCTA). Results In TAO patients, significant increases were found in macular and foveal vascular densities (FVD) and perfusion densities (FPD) while a significant decrease was found in the FAZ area when compared with the control group (p p = 0.032), FPD (β = -0.024, p = 0.042), MVD (β = -0.583, p = 0.020) and MPD (β = -0.011, p = 0.010). Clinical activity score (CAS) score showed positive correlation with FVD (β = 0.794, p = 0.035) and FPD(β = 0.017, p = 0.041). FVD (β = -0.009, p = 0.033), MVD(β = -0.034, p p = 0.039) and MPD(β = -2.428, p Conclusions There was an overall increase in superficial macular blood flow in TAO patients compared with healthy controls and the blood flow decreased as TAO got worse. Superficial macular flow density was negatively correlated with BCVA.

Based on the current training mode of postgraduats majoring in Naval Architecture and Ocean Engineering, taking the opportunity of applying for doctoral degree programs, we discussed the problems of existing postgraduates training mode, and put forward a new training mode that uses the leading role of the teacher team, attaches importance to the training of young teachers, improves scientific research, and builds a high-level academic platform for students to improve the quality of graduate students.

Brace structures with nonlinear stiffness are attractive in vibration mitigation. A new brace consisting of a novel convex column, which is characterized by the addition of a bulge structure compared to a column with constant cross-section, is proposed as a hysteresis brace structure with great applicability for mitigation of low-frequency vibration. The negative stiffness and D-shaped hysteresis damping of the proposed convex column brace generated by the buckling mode transition are verified theoretically and numerically. Comparisons of hysteresis characteristics of the proposed convex column brace and the one with the constant cross-section column are carried out to testify the outperformances of the proposed brace. The results demonstrate that the convex column brace can provide stronger bearing capacity with a smaller deflection and realize hysteresis damping within a shorter displacement range. In addition, a full parametric study is conducted to clarify the effects of geometric properties on hysteresis behavior. The investigation performed in this study not only demonstrates the great applicability of the proposed convex column brace, but also provides guidance on brace design for mitigation in practical application.

The motion response of a mat-support jack-up during positioning is studied in this paper using numerical analysis software SESAM. In the process of jack-up positioning, the square bottom mat is gradually lowered and the floating jack-up, secured by anchor chains, moves in six degrees of freedom in response to the dynamic loading of wave, current and wind combined. Numerical simulations are carried out to solve motion responses of the floating structure with mat at different depths. The sensitivity of motion responses to wave periods and directions are analyzed. The maximum motion amplitudes under the design environmental conditions and the risk of the mat crashing with the seafloor are evaluated.Copyright © 2015 by ASME