Abstract
<p>The Alto do Sobrido (AS) and Ribeiro da Serra (RS) Mines are old Sb-Au explorations. These are located in Gondomar, Portugal, on the inverse limb of the well-known structure called Valongo Anticline. In the AS Mine, the mineralization occurs near the contact between the Schist-Greywacke Complex (CXG) (Precambrian and/or Cambrian(?)) and the breccia of the base of the Carboniferous. In the RS Mine, the mineralization occurs only on the CXG. In both mines, the Sb-Au mineralization occurs in quartz veins and some stockworks.</p><p>A spatial correlation between the Sb-Au mineralization and the post-orogenic granites occurs in the Dúrico-Beirã Region according to Gumiel & Arribas (1987). Couto et al. (2007) also acquired data that suggests a genetic connection between this mineralization and non-outcropping granites. These granites may have been the source of fluids and a heat source that improved hydrothermal circulation and they have been observed in one of the RS Mine’s galleries.</p><p>With this hypothesis in mind, we intend to compare the data from a radiometric survey, which is a method that is radiometrically sensitive to K, Th and U at the near-surface, to the data from a gravimetric survey, which is a method that is sensitive to density anomalies at greater depths, in order to show if these granites could have chemically influenced its embedding rocks.</p><p>To make this comparison, we used the residual anomaly map from our gravimetric survey and the four maps obtained in the radiometric survey (total concentrations, K, eTh and eU). Firstly, we normalized all the grid maps to obtain grids with values between -1 and 1. Once this was complete, we multiplied each of the four radiometry maps to the residual anomaly map, obtaining the comparison maps.</p><p>On the resulting maps, we can observe high values in 3 different areas. The first corresponds to a lower value of gravimetric anomaly and a lower value of concentrations of all the elements. This area is located where the hypothesized non-outcropping granites are situated. The second area corresponds to high values on both methods. This matches the location of the lithologies from the Middle Ordovician to the Carboniferous, which are rocks of higher densities and higher concentration values of K, eTh and eU. The third area consists of lower gravimetric anomalies and lower concentrations of K and eU, and coincides with the location of the Ordovician quartzites. This area isn’t as visible on the eTh map, which is consistent with what was observed on the field.</p><p>We consider this approach to be a practical method to correlate the results of these two methods and an attempt to understand how the granite located at depth could have influenced these lithologies that today outcrop.</p><p><strong>References</strong></p><p>Gumiel, P., Arribas, A., 1987. Antimony Deposits in the Iberian Peninsula. Economic Geology, Volume 82, pp 1453-1463.</p><p>Couto, H., Borges, F. S., Roger, G., 2007. Late Palaeozoic orogenic gold-antimony deposits from the Dúrico-Beirã area (North Portugal) and their relation with hidden granitic apexes. Ninth Biennial SGA Meeting, Dublin. pp 609-612.</p>

Abstract
Robust wireless communication networks are a cornerstone of the modern world, allowing data to be transferred quickly and reliably. Establishing such a network at sea, a Maritime Internet of Things (MIoT), would enhance services related to safety and security at sea, environmental protection, and research. However, given the remote and harsh nature of the sea, installing robust wireless communication networks with adequate data rates and low cost is a difficult endeavor. This paper reviews recent MIoT systems developed and deployed by researchers and engineers over the past few years. It contains an analysis of short-range and long-range over-the-air radio-frequency wireless communication protocols and the synergy between these two in the pursuit of an MIoT. The goal of this paper is to serve as a go-to guide for engineers and researchers that need to implement a wireless sensor network at sea. The selection criterion for the papers included in this review was that the implemented wireless communication networks were tested in a real-world scenario.

Abstract
A linear electromagnetic energy harvesting device for underwater applications, fabricated with a simple manufacturing process, was developed to operate with movement frequencies from 0.1 to 0.4 Hz. The generator has two coils, and the effect of the combination of the two coils was investigated. The experimental study has shown that the energy capture system was able to supply energy to several ocean sensors, producing 7.77 mJ per second with wave movements at 0.4 Hz. This study shows that this energy is enough to restore the energy used by the battery or the capacitor and continue supplying energy to the sensors used in the experimental work. For an ocean wave frequency of 0.4 Hz, the generator can supply power to 8 sensors or 48 sensors, depending on the energy consumed and its optimization.

Abstract
Laboratories and industries that handle chemicals are ubiquitously prone to leakages. These may occur in storage rooms, cabinets or even in temporary locations, such as workbenches and shelves. A relevant number of these chemicals are corrosive, thus commercial products already exist to prevent material damage and injuries. One strategy consists of the use of absorbing mats, where few display neutralizing properties, and even less a controlled neutralization. Nevertheless, to the authors' knowledge, the commercially available neutralizing mats are solely dedicated to neutralizing acid or alkali solutions, never both. Therefore, this work describes the development and proof of a completely novel concept, where a dual component active mat (DCAM) is able to perform a controlled simultaneous neutralization of acid and alkali leakages by using microencapsulated active components. Moreover, its active components comprise food-grade ingredients, embedded in nonwoven polypropylene. The acid neutralizing mats contain sodium carbonate (Na2CO3) encapsulated in sodium alginate microcapsules (MC-ASC). Alkali neutralizing mats possess commercial encapsulated citric acid in hydrogenated palm oil (MIRCAP CT 85-H). A DCAM encompasses both MC-ASC and MIRCAP CT 85-H and was able to neutralize solutions up to 10% (v/v) of hydrochloric acid (HCl) and sodium hydroxide (NaOH). The efficacy of the neutralization was assessed by direct titration and using pH strip measurement tests to simulate the leakages. Due to the complexity of neutralization efficacy evaluation based solely on pH value, a thorough conductivity study was performed. DCAM reduced the conductivity of HCl and NaOH (1% and 2% (v/v)) in over 70%. The composites were characterized by scanning electron microscopy (SEM), differential calorimetry (DSC) and thermogravimetric analysis (TGA). The size of MC-ASC microcapsules ranged from 2 mu m to 8 mu m. Finally, all mat components displayed thermal stability above 150 degrees C.

Abstract
A piston type projector using the PVDF piezoelectric polymer was developed for operating in underwater environment, below 100 kHz. For those frequencies PZT piezoelectric ceramic is usually a preferable choice and PVDF is only considered for frequencies above a few hundreds of kHz. This paper will show that efficient underwater acoustic projectors for frequencies below 100 kHz can be implemented regarding an appropriate impedance adapter is being used. The developed project presents a calibrated transmitting voltage response (TVR) of approximately 166, 160 and 175 dB at 40, 50 and 75 kHz, respectively. The PVDF TVR values are compatible with the PZT projectors available on market with the advantage of having a larger bandwidth than most PZT projectors. To the authors knowledge this is the first time that a PVDF projector attain such characteristics. Although theoretically the PVDF projector bandwidth is larger than 40 to 80 kHz, in practice it was observed that only between those frequencies the project presents a stable operation for the transmission of long-term signals.

Abstract
The sedimentary processes play a major role in every aquatic ecosystem, however, there are few automated options for in-situ monitoring of sediment displacement in the streambed of waterways. We present an automated optical instrument for in-situ continuous monitoring of sediment deposition and erosion of the streambed that requires no calibration. With a production cost of 32euro, power consumption of 300 mu A in sleep mode, and capacity to monitor the bedform of a waterway, the sensor was developed to evaluate the sediment dynamics of coastal areas with a wide spatial and temporal resolution. The novel device is intended to be buried in the sand and uses 32 infrared channels to monitor the streambed sediment height. For testing purposes, a maximum measuring length of 160 mm and 5 mm resolution was chosen, but these values are scalable. Sensors can be built with different ranges and precision according to the needs of the fieldwork. A laboratory experiment was conducted to demonstrate the working principle of the instrument and its behaviour regarding the turbidity originated by suspended sediment and the settling and deposition of the suspended particles. The device was deployed for 119 days in an estuarine area and was able to detect patterns in the sediment deposition and resuspension during the tidal cycles. Also, abnormal events occurred during the experiment as floods and algae blooms. During these events, the sensor was able to record exceptional erosion and sediment deposition rates. The reported automated instrument can be broadly used in sedimentary studies or management and planning of fluvial and maritime infrastructures to provide real-time information about the changes in the bedform of the watersheds.