In the population increase and growing industrialization framework, NOx (NO and NO2) arises among the most important air pollutants responsible for various health and environmental conditions. Metal-organic frameworks, MOFs, are promising materials for NOx remediation. This study investigates the removal of nitrogen oxides (NOx) using metal-organic frameworks (MOFs). MOFs UiO-66, UiO-66-NH2, MIL-125, and MIL-125-NH2 were synthesized and characterized. The surface area of the MOFs was quantified, showing values like 1118 m(2)/g for UiO-66-NH2 and 1424 m(2)/g for MIL-125-NH2. The NOx removal efficiency using the NH2 functionalized MOFs reached 100 % efficiency under UV light. Moreover, the immobilization of MIL-125-NH2 in carrageenan/alginate matrices was investigated, maintaining significant NOx reduction capabilities similar to 80 %. This work also emphasizes the potential of MOFs by combining adsorptive and photocatalytic properties, providing insights into NOx capture and transformation mechanisms, and proposing a viable approach for sustainable air remediation technologies. This work paves the way for the successful applications of MOFs and MOF-modified membranes for air pollution mitigation.

Natural or industrial hexavalent chromium water pollution continues to be a worldwide unresolved threat. Today, there is intense research on new active and cost-effective sorbents for Cr(VI), but most still exhibit a critical limitation: their powdered nature makes their recovery from water cost and energy consuming. In this work, Al(OH)3, MIL-88-B(Fe), and UiO-66-NH2 Cr(VI) sorbents were immobilized into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymeric substrate to develop an easily reactivable and reusable water filtering technology. The immobilization of the sorbents into the PVDF-HFP porous matrix modified the macro and meso-porous structure of the polymeric matrix, tuning in parallel its wettability. Although a partial blocking of the Cr(VI) adsorptive capacity was observed for of Al(OH)3 and MIL-88-B(Fe) when immobilized into composite membranes, PVDF-HFP/UiO-66-NH2 filter (i) exceeded the full capacity of the non-immobilized sorbent to trap Cr(VI), (ii) could be reactivated and reusable, and (iii) it was fully functional when applied in real water effluents.

Aiming to improve the sustainability of materials for lithium‐ion batteries (LIBs), this work reports on the development of novel membranes based on iota‐carrageenan biopolymer and their suitability as separator in LIBs applications. The membranes are prepared by freeze‐drying and its morphology, thermal, mechanical, and electrochemical properties are evaluated as a function of polymer concentration in the solution. Porous membranes with a degree of porosity above 90% and different interconnected pore sizes between 50 and 70 µm for both polymer concentrations are obtained. The electrochemical parameters of the membranes are influenced by the carrageenan polymer concentration, being 1.34 mS cm ‐1 , 3, 7, and 0.48 for ionic conductivity, tortuosity, MacMullin number, and lithium transference number, respectively, for the membrane prepared from the 4 wt% carrageenan content solution. The half‐cells cathodic prepared with the developed membranes show good cyclability and rate capability. The discharge capacity values obtained with the membrane prepared from 4 wt% carrageenan content are 145 and 25 mAh g ‐1 at C/10‐ and 1C‐rates, respectively, demonstrating excellent battery cycling performance and long‐term stability. Thus, this work demonstrates that iota‐carrageenan biopolymer membranes developed by freeze‐drying can be used as separators for a next generation of more sustainable batteries.

Most electronic failures that occur in equipment are due to stresses induced by differences in the Coefficient of Thermal Expansion (CTE) of the different materials in a Printed Circuit Board Assemblies (PCBA). During a thermal cycle, the incompatibility of CTE between the PCB and the components induces shear fatigue that may affect the reliability of the solder interconnections on the PCB, which can eventually lead to fracture and failure of the joints and the PCB. Due to the advancement in the electronic components industry, interest from the researcher’s point of view has grown in studying the influence of additives in the solder alloys, in relation to microstructure, physical and mechanical properties and, mainly in the CTE. In this work two types of additives (Bi and graphite powder) were tested in order to reduce the CTE of a lead-free solder (SAC305) solder paste for reflow soldering. Because the selected additives have different characteristics, namely different densities, a different method of SAC305 solder additivation was tested for each type of additive. For Bi addition in SAC305 alloy (up to 6.5 wt.%), after a mechanical mixing of it, with the solder paste, a fusion technique (with a thermal cycle similar to the used on the reflow soldering) was used. For composites with graphite (addition up to 0.1 wt.%) a double-printing method was used in order to achieve a homogeneous additive distribution, so that graphite remained in the final ingot. These additivated solder alloys were chemically analyzed and characterized for thermogravimetric properties. Samples microstructure were characterized by SEM/EDS analysis, and also they were tested for their electrical resistivity. With graphite addition there is a slight increase on the initial alloy melting temperature (∼1.5°C) and with Bi an almost linear decrease was obtained (∼16 °C for the higher tested Bi addition). Composites with bismuth have a decrease trend, with the additive increase content until close to 5%. The CTE value decreases almost linearly ((from 25 to ∼14.5 μm/(m·°C); R2 = 0.9905). However, the sample of SAC305 + 6.5% Bi does not follow this trend, which may indicate that for these and higher amounts of bismuth, the composite CTE stabilizes. For composites with graphite there is a reduction of CTE (from 25 to ∼17 μm/(m·°C) for 0.04 wt. % graphite addition). For higher graphite additions the CTE seems to increase. The obtained results show that both additives can be used in order to achieve a CTE target value close to the PCB copper PAD (17 μm/(m·°C). However, the mixing method used for graphite mixing on solder paste cannot be directly transposed to the reflow soldering technique.

This work reports on the production of poly(vinylidene fluoride) (PVDF) membranes by non-solvent induced phase separation (NIPS) using N,N-dimethylformamide (DMF) as solvent and water as non-solvent. The influence of the processing conditions in the morphology, surface characteristics, structure, thermal and mechanical properties were evaluated for polymer dissolution temperatures between 25 and 150 °C and conditioning time between 0 and 10 min. Finger-like pore morphology was obtained for all membranes and increasing the polymer dissolution temperature led to an increase in the average pore size (≈0.9 and 2.1 µm), porosity (≈50 to 90%) and water contact angle (up to 80°), in turn decreasing the β PVDF content (≈67 to 20%) with the degree of crystallinity remaining approximately constant (≈56%). The conditioning time did not significantly affect the polymer properties studied. Thus, the control of NIPS parameters proved to be suitable for tailoring PVDF membrane properties.

LIDAR sensors are one of the key enabling technologies for the wide acceptance of autonomous driving implementations. Target identification is a requisite in image processing, informing decision making in complex scenarios. The polarization from the backscattered signal provides an unambiguous signature for common metallic car paints and can serve as one-point measurement for target classification. This provides additional redundant information for sensor fusion and greatly alleviates hardware requirements for intensive morphological image processing. Industry decision makers should consider polarization-coded LIDAR implementations. Governmental policy makers should consider maximizing the potential for polarization-coded material classification by enforcing appropriate regulatory legislation. Both initiatives will contribute to faster (safer, cheaper, and more widely available) advanced driver-assistance systems and autonomous functions. Polarization-coded material classification in automotive applications stems from the characteristic signature of the source of LIDAR backscattering: specular components preserve the degree of polarization while diffuse contributions are predominantly depolarizing.

LiDAR technology is bounded with great expectations. This is a result of the high market prospects from several industries (notably the automotive) as well as LiDAR being a key enabling technology for automation. We will drive along the current two main avenues of LiDAR, targeted to autonomous driving. We will stop at minute technicalities of LiDAR implementations. However, occasionally we will also rise high, to get an eagle-eye view of the bigger picture. We discuss why there will not happen a one-single-expensive-LiDAR-fits-all-scenarios and why a several-cheap-complementary-LiDARs alternative is more rational. We discuss several aspects in which LiDAR changed our understanding of the landscape as well as the high impact it will have in society (economic and quality of life). Automotive LiDAR comes in an age where the societal focus is changing from private ownership to pay-as-you-use-services, and where personal responsibility will be gradually replaced by corporate liability. We will introduce some minor contributions from the Physics Centre of Minho and Porto Universities (mutual interference between commercial sensors; data processing in timing the back scattered LiDAR signal). And by the end of the route, we drop off the partaker to explore uncharted territory on its own.

Smart materials for sensor applications are increasingly being used in a wide variety of applications ranging from engineering to medical devices. This work reports on piezoresistive sensors based on conductive polyaniline and thermoplastic elastomer processed by conventional polymer extrusion. The material presents excellent process-ability and piezoresistive performance offering an alternative to traditional composites with conductive nanofillers for sensor applications. The polyaniline/styrene-butadiene-styrene (PANI/SBS) conductive polymer blends present good mechanical properties, high electrical conductivity and piezoresistive response. The maximum strain reaches approximate to 60% for 30 weight percentage (wt%) PANI content and the electrical conductivity is sigma approximate to 0.1 S/m for blends with 40 wt% PANI content. Further, the sample with 40 wt% PANI content shows a piezoresistive gauge factor GF approximate to 1 for deformation measurements between 0.1 and 3 mm in bending cycles. (C) 2017 Elsevier Ltd. All rights reserved.