Ship collision impact on the structural load of an offshore wind turbine

When a maintenance and operations ship is berthing,there is a chance the ship may collide into the wind turbine.When these ships collide into wind turbine structures,this can result in significant changes to the foundation and structure of the wind turbine.In this paper,the structural load of a 4 MW offshore wind turbine was analyzed during a collision with an operations and maintenance ship.The variations in the wind speeds on hub height,waves,and the sea currents were measured.The dynamic simulation of the wind turbine was carried out using the test data as the input parameters.As a result,the load condition of the turbine without a collision was obtained.Finally,the measured turbine load was compared with the simulation results.This study shows that the collision of the operation and the maintenance ship increases the bending moments at the tower’s bottom and the blade’s roots.

Preparation of nanometer yellow iron and its UV absorption capacity

The nanometer yellow iron oxide was prepared by oxidizing Fe（OH）2 with air, which was verified with XRD and TEM. The result shows that nanometer yellow iron oxide is spindle-shaped and well-distributed with a long axis of 150-200 nm and short axis of 40-50 nm. Ultraviolet （UV） transmittance of the iron oxide shows the great effect of concentration on both transparency and UV ab- sorption, and it has been proven that iron oxide with a concentration of 0.025wt% is preferred. The spectrum of XRD indicates that it is goethite. When the yellow iron is dispersed in sol, given that the wavelength of UV is less than 300 nm, its UV absorption capacity is superior to those of ZnO and TiO2. The absorption capacity of the yellow iron is less than TiO2 and more than ZnO as the wavelength of UV is 300-400 nm.

Synthesis of Self-assembled Star/Linear Block Copolymer Blends via Aqueous RAFT Dispersion Polymerization

Reversible addition-fragmentation chain transfer(RAFT)-mediated polymerization-induced self-assembly(PISA)of star block copolymer and linear block copolymer using a binary mixture of a star-like macro-RAFT agent and a linear macro-RAFT agent is reported.With this formulation,star block copolymer and diblock copolymer were formed simultaneously to generate colloidally stable star/linear block copolymer assemblies.Size exclusion chromatography(SEC)analysis confirmed the presence of two types of polymers in the final samples.The molar ratio of the star-like macro-RAFT agent and the linear macro-RAFT agent has a significant impact on the morphology of polymer assemblies.It was found that increasing the amount of star-like macro-RAFT agent facilitated the formation of higher-order morphologies.Additionally,effects of other reaction parameters including the length/number of the arm of the star-like macro-RAFT agent,degree of polymer(DP),monomer concentration on the morphology of star/linear block copolymer assemblies were also investigated.We expect that this work will offer new possibilities for the scalable preparation of polymer assemblies with unique structures and functions.

Catalyst-free electrochemical dearomatization of pyridine derivatives

We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.

Study on grid adaptability testing methodology for wind turbines

The use of wind power has grown rapidly in recent years.Wind power is a clean source of energy,but can have negative impacts on the distribution grid.The influence of large-scale wind power integration on the safe and stable operation of a power system cannot be ignored.It is necessary and urgent to achieve grid adaptability for wind turbines in China.Using a 35 kV/6 MVA grid simulator,the performance of a grid is investigated by simulation.Typical grid disturbances such as voltage deviation,frequency fluctuation,voltage unbalance,and distortion can be simulated.A grid adaptability testing methodology was developed and applied to a doubly fed wind turbine with a focus on analyzing real test data to ascertain its three-phase voltage unbalance adaptability,which was successfully demonstrated.The methodology can also be used to guide other grid adaptability tests.