Abstract
Located in the northern part of continental Portugal, the city of Porto is characterized by low-to-moderate levels of seismicity, thus one of reasons for the lack of studies regarding the influence of site effects in this area. In this study, the HVSR technique (horizontal-to-vertical spectral ratio) was used in order to obtain information about the fundamental frequencies of the ground in several parts of the city which was later compared to the geotechnical information presented in the Geotechnical Map of Porto, with the aim of establishing a possible correlation between frequency values and sub-soil geotechnical characteristics. This type of research plays an important role in understanding how local geological characteristics may influence the amplification of seismic waves. For this purpose, two types of studies were conducted in the city of Porto – two linear test campaigns along two major streets in the city, Boavista Avenue and Constituição Street; and one dispersed test campaign within the hydrographic basin of Frio River, an underground river flowing in the areas of Carregal Garden, Santo António Hospital, Cordoaria Garden and Virtudes Garden. The three campaigns represented a total of 53 recordings of ambient ground noise using a broad band seismometer and the resulted data was used to produce HVSR graphics. From these graphics it was possible to determine the fundamental frequencies (f0) of several points within the city. Resorting to the geotechnical map of the city and having identified the geotechnical units existing in each test place as well as the parameters used to their classification, it was possible to establish a connection between frequency values and substrate competence. The results suggest a strong relation between these parameters, low frequencies relate to softer grounds and as an opposite high frequencies to harder bedrock.

Abstract
The present work shows some results obtained by the Time-Domain Electromagnetic Method (TDEM) to help characterize the geology and Penacova- Régua-Verin fault structure in the Vila Pouca de Aguiar sector. The Fault is an important tardi-variscan structure with NNE-SSW direction, more than 500 km long, extending from the North of Spain until near Nazaré. The application of the TDEM method aimed to acquire data towards obtaining profiles of subsurface electrical resistivity in the zone affected by the fault and adjacent terrain. Electrical resistivity profiles, resulting from the combination of individual soundings, were performed in the SW quadrant of 6D-Vila Pouca de Aguiar of Carta Geológica de Portugal sheet, at a scale of 1/50 000, along Penacova-Régua-Verin Fault and perpendicularly, with WNW-ESE orientation, in the western sector of the fault. Some confirmation and preliminary models were accomplished using the results obtained by other authors, allowing to verify the validity of the obtained inverted data. The method responded in accordance with the conceptual model but allowed the additional distinction between alteration zones and apparently identical lithologies. Overall, three main blocks were identified, the most superficial shows high resistivities and low thickness. The second block has lower resistivity values due to the influence of the water level at this depth. In the third block, more oscillatory characteristics were identified throughout the various surveys. Although, in general, its high thickness and high values of electrical resistivity were highlighted. However, one of the obstacles in the implementation of the method was the presence of wind farms in Northern Portugal, bridges, metal fences, as well as power lines and high voltage pylons that produce electromagnetic noise and thus interfere with the readings obtained.

Abstract
The geophysical surveys methods have not been extensively used in gold exploration in Northern Portugal. This is based on the fact that most mineralized zones contain low and erratic sulphide contents. In this work we3re tested three different types of geophysical surveys combined with geochemical surveys, in order to define anomalies that are closely correlated with the locations of known mineralized zones. The aim of the work is to study some gold deposits in Northern Portugal (Lagoa Negra and Castromil) with the purpose of obtaining valuable information of the mineralogical and petrogenetically features of these gold deposits, and how it would facilitate the understanding of the regional distribution and formation of gold deposits. Ground Penetrating Radar (GPR), Very Low frequency (VLF) electromagnetic methods combined with 2D Electrical Resistivity techniques can contribute towards defining structures, and are particularly important where extensive cover exists and may also play an important role in the mapping of lithology and the lithological contacts. The magnetic surveys revealed and confirmed two possible areas with sulphide mineralization, one with pyrrhotite and other with Fe-sulphide oxidation proven by during drilling campaign in this area. This work demonstrates how the combination of geophysics and geochemical methods, together with geological sampling, can be used to help delineate possible structures that host gold mineralization.

Abstract
This paper focuses on the susceptibility evaluation to bank gullies on earthen embankments through the application of SIMWE (SIMulated Water Erosion) model, using a high resolution digital elevation model (1 meter spatial resolution). The results provided by the model are compared with the hydrologic characteristics, soil texture and soil structure of the agricultural terraces. This approach demonstrates an association between the spatial distribution of erosive forms with high values of water depth and reduced water discharge that are consistent with the lower values of electrical resistivity. The areas with the highest percentage of erosive forms, related to sediment flux, transport capacity and sediment concentration susceptibility, assume medium values. These figures, combined with a low hydraulic conductivity and soil infiltration capacity, are consistent with the fine texture of soils, allowing increased runoff and the development of linear erosion.

Abstract
This work aims to study a new energy harvesting device to be anchored on the ocean floor and convert any type of currents, tides or oscillation movement into electrical energy using linear electromagnetic generators. The final application is to supply energy to a set of moored monitoring sensors that collects data and allowing the system to be energetically autonomous. The proposed setup is a spherical buoy with no external moving parts, to be more biofouling proof. The maximum output power measured for a 4 Hz movement was 9.9 mW with only one linear electromagnetic generator.

Abstract
This work describes the development and characterization of a wide beam and wideband ultrasonic transducer, designed as an emitter for underwater communications up to 1.5 MHz. The active element being used is composed of two layers of 110 mu m PVDF (Polyvinylidene fluoride) film, with NiCu electrodes. The transducer has a semicircular shape with a diameter of 15 cm. Pool trials show a transmitting voltage response of approximately 150 dB re mu Pa/V @ 1m from 750kHz to 1MHz and higher than 130 dB re mu Pa/V @ 1m between 250kHz and 1.5MHz. At 1 MHz, when excited with 12V, the transducer has a power consumption of 37.5 mW.