Abstract
In this work a strain sensor based on a suspended core fiber is proposed. The sensor comprises a suspended core PCF between SMFs and is based on the multimode interference generated in these transitions. A strain sensitivity study for different sensing heads and stage separation lengths was carried out showing a sensitivity of -2.42 pm/mu epsilon for the best case. Also the sensing head was tested for curvature and temperature, showing in the first case that it is insensitive to curvature effects, and secondly, that for small sensor lengths it was insensitive to temperature variations.

Abstract
A multimodal interferometer based on a new microstructured fiber tip is proposed for detection of the evaporation process of acetone. The new geometry consists of a capillary tube in which an offset Ge-doped core is fused and spliced at the end of a single-mode fiber. The fiber tip sensor structure was immersed in liquid acetone and the evaporation process of acetone was monitored in real time. Due to the refractive index variation of the external medium with increasing temperature, a short detection time of similar to 1 s was achieved. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)

Abstract
Surface Plasmon Resonance (SPR) is the base for some of the most sensitive label free optical fiber biosensors. However, most solutions presented to date require the use of fragile fiber optic structure such as adiabatic tapers or side polished fibers. On the other hand, long-period fiber gratings (LPG) present themselves as an interesting solution to attain an evanescent wave refractive index sensor platform while preserving the optical fiber integrity. The combination of these two approaches constitute a powerful platform that can potentially reach the highest sensitivities as it was recently demonstrated by detailed theoretical study [1, 2]. In this work, a LPG-SPR platform is explored in different configurations (metal coating between two LPG - symmetric and asymmetric) operating in the telecom band (around 1550 nm). For this purpose LPGs with period of 396 mu m are combined with tailor made metallic thin films. In particular, the sensing regions were coated with 2 nm of chromium to improve the adhesion to the fiber and 16 nm of gold followed by a 100 nm thick layer of TiO2 dielectric material strategically chosen to attain plasmon resonance in the desired wavelength range. The obtained refractometric platforms were then validated as a biosensor. For this purpose the detection of thrombin using an aptamer based probe was used as a model system for protein detection. The surface of the sensing fibers were cleaned with isopropanol and dried with N-2 and then the aminated thrombin aptamer (5'-[NH2]-GGTTGGTGTGGTTGG-3') was immobilized by physisorption using Poly-L-Lysine (PLL) as cationic polymer. Preliminary results indicate the viability of the LPFG-SPR-APTAMER as a flexible platforms point of care diagnostic biosensors.

Abstract
A new type of fibre-optic refractive index sensor based on a long period fibre grating (LPFG) coated with a titanium dioxide (TiO2) thin film was demonstrated. The wavelength shift of the attenuation bands of this LPFG sensor to changes in the refractive index of the external media from 1.30 to 1.64 RIU was investigated. In order to optimize the sensor the TiO2 thin film thickness deposited around the LPFGs was varied from 10 to 80 nm. It was found that the TiO2 thin film increases the wavelength sensitivity of the LPFG to changes in the surrounding refractive index for values lower and higher than the cladding refractive index. As opposed to the bare LPFG it was shown the possibility to monitor refractive indices lower and higher than cladding refractive index tailoring the TiO2 thickness. An average wavelength sensitivity of 5250 nm/RIU was achieved in the range 1.444 to 1.456 RIU for a TiO2 thickness of 50 nm. In the region between 1.46 and 1.48 RIU the average sensitivity of about 825 nm/RIU was measured for a 40 nm thick film.

Abstract
Despite the socio-economic importance of mining in Douro Coalfield, the coal exploitation and utilization originated impacts on the environment. From these stands out the S. Pedro da Cova waste pile which is self-burning since 2005. The potential environmental impacts associated with this coal waste pile include: air pollution caused by the gaseous emissions and dispersion of solid particles; pollution of soils, surface and groundwater caused by mobilization of solid particles, leaching of hazardous elements, dissolution of neoformed and deposition of solid particles; landslides and mass movements also caused the weathering agents, and deterioration of vegetation that may also be due to the acid drainage. The main objective of this work is the combustion temperature monitoring in S. Pedro da Cova waste pile using the infrared thermography technique. The acquired results during the temperature monitoring campaigns allow the study of the dynamics and evolutionary scenarios of the self-burning process in the coal waste pile, contributing to a precise definition of the risks to the environment and human health. © 2014, LNEG – Laboratório Nacional de Geologia e Energia IP.

Abstract
A segment of a suspended-core microstructured fibre was dipped in a droplet of acetone and the evaporation dynamics of remaining acetone inside the cavity were simultaneously analysed with an optical microscope and an optical spectrum analyser. When the fibre is immersed it suffers a 14 dB signal drop. Different menisci form in each cladding cavity, with different evaporation times and rates. The signal restores its initial state not when the evaporation process is complete but after the collapse of a dominant meniscus.