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Recently, research results on PC-based or alkali-activated slag cement (AASC) using seawater as mixing water have been reported. Unlike seawater, reverse osmosis brine (brine) is waste discharged into the ocean from seawater desalination plants. There is a need to develop new and effective methods of disposing or utilizing brine to reduce marine pollution, protect marine ecosystems, and increase marine plant construction. However, research on cement or concrete using brine as a mixing water is very limited. Brine has almost the same composition as seawater, and the ion concentration is 2–4 times higher. Therefore, it is believed that new methods of using brine can be investigated and developed based on existing research and experimental results on seawater. The effects of brine and aluminum oxide (AO) on activated slag with calcium hydroxide (CH) were investigated for hydration and mechanical properties. 5% and 10% of CH were used, and samples using fresh water (FC) were prepared at the same time for comparison with brine. The slag sample without CH has a low initial (1 and 3d) strength of about 10 MPa for both FC and brine, but increases rapidly from 7d. Incorporation of CH was effective in improving the mechanical performance of FC and brine samples. In addition, the brine sample exhibited higher strength than the FC sample because it formed fewer C3AH6 phases that cause volume instability than the FC sample and affected the hydration promotion of slag particles. And more calcite phases were observed in the brine samples than in the FC samples. Through this study, the possibility of using brine as a building material was confirmed. In addition, the effect of chloride ion adsorption of slag mixed with AO and CH on the physical properties and mechanical performance of the hydration reaction was confirmed. [ABSTRACT FROM AUTHOR]

In this study, a new method of fabricating a composite frequency selective surface (FSS) using an e‐beam evaporator is proposed. The FSS is designed and fabricated as a part of the structure surface. A new concept of FSSs integrated into a composite skin structure provides a design that is electrically and structurally effective. This manufacturing process has the advantage of direct application of FSS function in a real structural surface with varied conformal skin. The multilayered FSSs of the patch‐grid‐patch type consist of a copper layer as a capacitive or inductive surface on a glass/epoxy pre‐impregnated (prepreg) substrate. The copper layer forming the FSS is manufactured using the e‐beam deposition on a glass/epoxy prepreg. The bandwidth of the designed FSS increases three times. The difference between the simulated and the measured results is due to the different evanescent wave interactions between the capacitive layers and inductive layer such as the local misalignment of the patch and grid, size of the specimen, and change in the thickness of the dielectric substrate after the manufacturing process. The bandwidth is successfully modified by correcting the design parameters such as the period, patch gap, grid width, and dielectric thickness. The band‐pass filtering and skirt characteristics appear in the experimental results, which agree well with the simulated results. This method is remarkably simple, and the manufactured FSS can function as both a structural skin and an FSS. Moreover, it has the merit of manufacturing simplicity and realization of structural shape. [ABSTRACT FROM AUTHOR]