To examine the damages of structure in use is generally a challenging task., particularly when a fast inspection is required by using limited tools or even the bare eyes. The other challenge is how to evaluate the damage state after the fast safety examination. Most well know damage indexes for the structure are for the design purposes such as to estimate the possible damage state when structure is under extraordinary loading condition. The index must relate to the maximum force applied and maximum deflection or plastic deformation. To have structure's real response is generally impossible unless on-line monitoring is applied. Therefore, it is the interest of this study to find a means to evaluate the damage state through the limited data obtained by bare-eye examination or using limited tools. The evaluation was performed in the laboratory by testing the scaled down beam models and compared the data obtained by limited tools to the one obtained through data acquisition system. It was found that for the large scale, fast structure inspection this new developed simplified damage index may provide a convenient means for the damage evaluation of the structures.
Na 2 O-Nb 2 O 5 -SiO 2 based glass-ceramics with and without ZrO 2 /TiO 2 were prepared by controlled crystallization, and their crystallization properties under different heat-treatment temperatures were characterized by differential scanning calorimetry, X-Ray Diffraction (XRD) and morphology observation. The XRD results indicated the presence of NaNbO 3 with perovskite structure as the major crystalline phase. The introduction of ZrO 2 contributed to the stabilization of the Na 2 O-Nb 2 O 5 -SiO 2 basic glass, and thus improved their crystallization. Moreover, changes of the dielectric constant of the glass-ceramics with the frequency and measuring temperature were mainly studied. In details, the maximum dielectric constant reached 136.9 (@1000 KHz, 25 • C), and the rate of change with temperature is as small as about −0.0302/ • C. The crystalline glass remains transparent in the range of 400-800 nm, and the transmittance is above 70% for the 2 mm thick sample.
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