Core-shell structures were prepared using silica from Lapindo mud extract. The XRD results showed that the extracted silica contains γ-Al 2 O 3 and NaAlSi 3 O 8 . Besides, the FT-IR, Raman spectroscopy, and FE-SEM analyses showed that the core particles were not finely covered by the shell. BET measurement indicated that high surface areas are attainable for core-shell structures addition into TiO 2 nanoparticles. TiO 2 /TiO 2 @SiO 2 core-shell structure has 161.100 m 2 /g and 0.311 cc/g of surface area and pore volume, respectively. Whereas, TiO 2 /SiO 2 @TiO 2 core-shell structure has surface area of 140.200 m 2 /g and pore volume of 0.292 cc/g.

This paper presents a long-range displacement measurement method by using a singlemulti-single mode (SMS) fiber structure, attached to a flexible plate between two permanent poles and the optical time domain reflectometer (OTDR)-based interrogator. The SMS fiber structure sensors are prepared with two different configurations, i.e. straight and sinusoidal configurations. It is demonstrated that the displacement sensor can perform a displacement measurement with a range from 0 mm to 150 mm with a resolution of 0.159 mm. The sinusoidal configuration provides a better sensitivity than the straight configuration. The proposed sensor offers a low cost, and it can be implemented for quasi-distributed displacement measurement which is suitable for civil structure monitoring.

This article presents a strain measurement method using a singlemode‐multimode‐singlemode fiber structure sensor and an optical time domain reflectometer. A strain measurement range of 0–1000 με can be achieved with a resolution of better than 10 με. Using this method, a quasi‐distributed strain measurement can be carried out which is useful for a bridge or a civil structure strain monitoring. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2576–2578, 2013

Abstract:A singlemode-multimode-singlemode (SMS) fiber structure for temperature measurement using an optical time domain reflectometer (OTDR)-based interrogation system is proposed. A temperature measurement range of 40 ℃-195 ℃ with a resolution of 0.12 ℃ and a linearity of 0.992 could be achieved for the multimode fiber (MMF) graded index with a length of 60 mm. It was also demonstrated that two-point temperature measurement with two SMS fiber structures as temperature sensors could be made. The proposed temperature measurement system offered a high resolution and also benefited from a simple configuration with a capability of multi-point temperature measurement.

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