Search

Journal of power sources 529, 231221 (2022). doi:10.1016/j.jpowsour.2022.231221, Published by Elsevier, New York, NY [u.a.]

Experimental investigation of the amplitude characteristics of wind loads on a square cross-sectional tall building under the combined aerodynamic control, which consists of the shape modification and air suction, has been conducted, and the effects of the suction flux coefficients CQ and wind direction angles on the wind pressure coefficients and aerodynamic force coefficients of five test models (includes a square cylinder and its corner modifications such as recession and chamfer, tapered cylinder and Y-shaped cylinder, and they are denoted as the Models 1–5 respectively) with and without air suction control have been analyzed. The Model 1 without suction control is defined as the benchmark model. The results show that the shape modifications have significant control effects on the mean and RMS pressure drag coefficients (CD and CσD) as well as the RMS pressure lift coefficient CσL of the Models 2, 3 and 5 at 0° wind direction, with the maximum reduction rates (CDR, CσDR and CσLR) of 39.2%, 44.0% and 38.4% for the Models 2, 5 and 2 respectively. When compared with the benchmark model, the most significant control effects of the combined aerodynamic control on CDR, CσD and CσL of the Models 2–5 with the suction speed of 9 m/s are also at 0° wind direction, with the maximum reduction rates of 61.8%, 65.8% and 5.7% for the Models 2, 2 and 5 respectively, which indicates that the combined aerodynamic control is more effective on the drag reduction than the passive or active aerodynamic control individually, and the Model 2 with suction control has the best wind-resistant performance. This study contributes to an effective aerodynamic measure to control the amplitude characteristics of wind loads on tall buildings, which can be an important reference for further studies or potential engineering applications of the combined aerodynamic control in mitigating the wind loads and wind-induced responses of tall buildings.

Single material TiO2 was used to fabricate the double layers antireflection coating with photocatalytic property. TiO2 layers with low and high refractive indices were prepared by the direct reactive magnetron sputtering technique and energy filtrating magnetron sputtering technique, respectively. The structure, surface morphology and optical property were tested by X-ray diffraction, field emission scanning electron microscope and spectroscopic ellipsometer. The photocatalytic property of the coating was evaluated by UV–vis spectrophotometer. Results suggested that the coating had both antireflective and photocatalytic performances. The refractive indices of the top and bottom TiO2 layers were 2.10 and 2.47 (at 600 nm), respectively. The average and max transmissivities were obtained of 88.4% and 98.9% in the wavelength range of 400–800 nm and the degradation rate on Rhodamine B was obtained of 0.0034 min−1.

Titanium dioxide (TiO 2 ) thin films were deposited by DC magnetron sputtering (DMS) using an orthogonal experimental design approach. The optimized parameters were investigated. At the optimized condition, TiO 2 film was fabricated by the energy filtrating magnetron sputtering (EFMS) technique. The crystal structure and surface morphology of the film were determined by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The optical property was examined by a spectroscopic ellipsometer. The photocatalytic activity was tested by a UV–vis spectrophotometer, irradiated by the ultraviolet light. Results suggested that the TiO 2 films were well crystallized of the anatase phase without subsequent annealing. TiO 2 film deposited by the EFMS technique had a dense surface morphology consisting of smaller particles. Because of the smaller particles, larger contact area and higher band gap (3.40 eV) were generated. As a result, an improved degradation rate of rhodamine B at 0.00267 min −1 was obtained for the film prepared by the EFMS technique.