Abstract
AbstractIn this study, the geochemistry and mineralogy of regoliths formed on Fogo Island (Cape Verde), a polygenic stratovolcano built during the Quaternary, are used to assess the geomorphological factors that control the early stages of basalt weathering. Fogo Island soils are mainly derived from relatively homogenous silica-undersaturated basaltic rocks. However, a discernible exotic component is recognised in areas most exposed to prevailing winds by ratios on non-mobile elements that are hosted in different amounts by basaltic rocks (e.g., Th, Sc and Ti). Weathering extent is evidenced by a relative depletion in mobile elements (e.g., Na, Ca, Mg) and an enrichment in non-mobile elements (e.g., Ti, Fe, Sc, Al), the decomposition of the most labile minerals (olivines), and the enrichment in secondary components (phyllosilicates and some Fe-oxides, such as hematite-goethite), along with quartz supplied from non-volcanic areas. It depends on bedrock age and type (pyroclastic deposits vs. lava-flows). In particular, soils covering older volcanic units tend to be more affected by chemical alteration than those overlying younger units. In addition, more intense weathering is observed in locations characterised by a combination of moderate elevation, slopes with low gradient and relatively high rainfall. The present investigation shows that even in low humidity environments recently formed basalt are affected by weathering, with the extent of chemical decomposition being mainly determined by the age of surface exposure and local orographic/climatic features.

Abstract
Geophysical techniques can be successfully applied towards the detection of buried explosive devices, the ground-penetrating radar (GPR) being an example of one such method. This technology works through emission and reception of electromagnetic radio waves being thus able to detect the presence of a subsurface object fundamentally due to reflections from contrasting electromagnetic properties between the object and the surrounding medium (e.g., soil). Many factors can influence the success of a GPR survey (e.g., target type, soil type, environmental conditions, GPR antenna frequency, data processing techniques), being essential to know and understand their likely effects before performing GPR studies, mainly in real cases. In this paper, through the analysis of case studies related to the use of GPR technology towards the detection of buried explosive devices, we intend to arrange and layout the main prior knowledge that a forensic geophysical expert must have when dealing with this type of fieldwork.

Abstract
Rehabilitation, restoration and maintenance of monuments, heritage and buildings pose challenging tasks to engineers and architects, as any intervention must respect their architectural and constructive characteristics. Often these are unknown and sources of information have long been lost in time. Thus, there is a need to use methods capable of providing information on a wide range of aspects such as building foundations, construction characteristics and materials, alterations from the original layout, infrastructure mapping, pathologies, etc. These methods must respect the inherent structural delicacy and characteristics of ancient buildings and non-destructive methods, NDT such as geophysical methods, have been proposed to investigate these problems. It is common knowledge that a single geophysical method cannot provide full information on the problems to investigate. Thus, herein the combined use of Seismic Transmission Tomography and Ground Penetrating Radar - GPR - is demonstrated to provide important results in the investigation of the constructive elements (columns and walls) of a 14th century UNESCO monument. As demonstrated, high-resolution geophysical data obtained from both methods provide very good images of the interior of both walls and columns giving information on the quality and spatial distribution of the materials used in the construction of the monument. Finally, the results herein discussed prove the suitability and complementarity of these two methods to investigate, built heritage, monuments and buildings in general.

Abstract
Poly(vinyl alcohol) (PVA) in multifilament and braided yarns (BY) forms presents great potential for the design of numerous applications. However, such solutions fail to accomplish their requirements if the chemical and thermomechanical behaviour is not sufficiently known. Hence, a comprehensive characterisation of PVA multifilament and three BY architectures (6, 8, and 10 yarns) was performed involving the application of several techniques to evaluate the morphological, chemical, thermal, and mechanical features of those structures. Scanning electron microscopy (SEM) was used to reveal structural and morphological information. Differential thermal analysis (DTA) pointed out the glass transition temperature of PVA at 76 & DEG;C and the corresponding crystalline melting point at 210 & DEG;C. PVA BY exhibited higher tensile strength under monotonic quasi-static loading in comparison to their multifilament forms. Creep tests demonstrated that 6BY structures present the most deformable behaviour, while 8BY structures are the least deformable. Relaxation tests showed that 8BY architecture presents a more expressive variation of tensile stress, while 10BY offered the least. Dynamic mechanical analysis (DMA) revealed storage and loss moduli curves with similar transition peaks for the tested structures, except for the 10BY. Storage modulus is always four to six times higher than the loss modulus.

Abstract
Estuaries have the particularity of being in constant change concerning the salinity of the water, since the river carries fresh water to the mouth, while the force of the tide pushes salty water upstream, reaching several kilometers upstream given the right conditions. These bodies of water do not mix instantly, allowing the appearance of a distinct border between the two, known as the front. This document presents a monitoring system composed of four-probe salinity sensors, which acquire conductivity, temperature, and pressure data to calculate salinity, arranged in such a way as to make measurements along the water column, to detect the shape of the front, as well as monitoring the estuary. The sensors, and the monitoring system in general, are cost-effective, low-power, and accurate in long-term deployment, even when installed in adverse conditions such as at sea. The sensors consume $26 \mu \mathrm{A}$ in sleep mode and 10 mA during measurement, and the measurement time is less than 100 ms. The choice of a four-point configuration allows overcoming the inevitable decay of the electrodes and possible measurement errors, contributing to autonomous long-term operation.

Abstract
The present work shows the development of a linear electromagnetic generator (LEG) for applications in marine and fluvial sensors. The LEG was submitted to tests with small oscillating frequencies of 0.1-0.4 Hz, and the output power obtained for these frequencies has allowed to supply energy to at least 6 sensors with a total consumed power of 5.76mW or to charge the batteries when the sensors are in a sleep mode. As a result, it is possible to extend the operation time and reduce the logistic costs for sea or river sensors applications, by using the proposed micro underwater generator.