Online monitoring of carbon fiber reinforced plastic (CFRP) ropes requires non-destructive testing (NDT) methods capable of detecting multiple damage types at high inspection speeds. Three NDT methods are evaluated on artificial and realistic imperfections in order to assess their suitability for online monitoring of CFRP ropes. To support testing, the microstructure and electrical conductivity of a carbon fiber rope is characterized. The compared methods are thermography via thermoelastic stress analysis, ultrasonic testing with commercial phased array transducers, and eddy current testing, supported by tailor-made probes. While thermoelastic stress analysis and ultrasonics proved to be accurate methods for detecting damage size and the shape of defects, they were found to be unsuitable for high-speed inspection of a CFRP rope. Instead, contactless inspection using eddy currents is a promising solution for real-time online monitoring of CFRP ropes at high inspection speeds.

Online monitoring of carbon fibre reinforced polymer (CFRP) components requires a Non-Destructive Testing (NDT) method capable of contactless sensing of damage, while enabling high inspection speeds needed for monitoring large components. Eddy current testing (ECT) of CFRP components has great potential for two reasons. First, ECT probes are capable of operating without contact, although minimizing the lift-off is preferred. Second, impedance analysers with high sample rates make high-speed inspection possible. This research assesses the damage detection capabilities of eddy current probes on CFRP samples with artificial and realistic damage. To support the aptitude of the ECT method for these needs, the CFRP material is characterized and numerical simulations are performed in order to develop optimized and tailored ECT probes for the detection of defects with different morphologies, namely fibre breakage and delaminations, and to take into consideration the highly anisotropic electrical bulk resistivity of the CFRP material. Different ECT probes were designed, produced and experimentally validated. The experiments were performed at a high inspection speed (4 m/s) and the high sensitivity of the probes was demonstrated.

Antimicrobial resistance is one of the most worrying threats to humankind with extremely high healthcare costs associated. The current technologies used in clinical microbiology to identify the bacterial agent and profile antimicrobial susceptibility are time‐consuming and frequently expensive. As a result, physicians prescribe empirical antimicrobial therapies. This scenario is often the cause of therapeutic failures, causing higher mortality rates and healthcare costs, as well as the emergence and spread of antibiotic resistant bacteria. As such, new technologies for rapid identification of the pathogen and antimicrobial susceptibility testing are needed. This review summarizes the current technologies, and the promising emerging and future alternatives for the identification and profiling of antimicrobial resistance bacterial agents, which are expected to revolutionize the field of clinical diagnostics.

Polymeric parts produced by Fused Deposition Modelling (FDM) Additive Manufacturing (AM) has no special safety requirements, and therefore, NDT is not required. However, the use of AM to produce Fibre Reinforcement Thermoplastics (FRTP) parts means that structural applications with safety requirements are envisaged, demanding reliable NDT methods. This paper presents experimental results and numerical simulation by Finite Element Method (FEM) of the NDT inspection of different parts of polymeric and RFTP composite materials. The parts were produced by FDM Additive Manufacturing and different delamination defects were introduced at different positions and with different dimensions and morphologies. Two different NDT techniques were used, exploiting different inspection parameters: air-coupled ultrasound, using frequencies between 50 and 400 kHz and active transient thermography, in both reflection and transition modes. The influence of the curvature of the parts was analysed, from the experimental point of view, and the results were compared with different numerical simulation strategies. It was shown that, both NDT techniques can detect the defects, with good spatial resolution, being the thermography reflection mode the fastest and expedite for curvature parts. The numerical simulation corroborates the experimental results allowing a deeper insight on the physical phenomena involved.

The use of non-destructive evaluation (NDE) techniques for assessing microstructural changes in processed materials is of particular importance as it can be used to assess, qualitatively, the integrity of any material/structure. Among the several NDE techniques available, electrical conductivity measurements using eddy currents attract great attention owing to its simplicity and reliability. In this work, the electrical conductivity profiles of friction stir processed Ti6Al4V, Cu, Pb, S355 steel and gas tungsten arc welded AISI 304 stainless steel were determined through eddy currents and four-point probe. In parallel, hardness measurements were also performed. The profiles matched well with the optical macrographs of the materials: while entering in the processed region a variation in both profiles was always observed. One particular advantage of electrical conductivity profiles over hardness was evident: it provides a better resolution of the microstructural alterations in the processed materials. Moreover, when thermomechanical processing induces microstructural changes that modify the magnetic properties of a material, eddy currents testing can be used to qualitatively determine the phase fraction in a given region of the material. A qualitative relation between electrical conductivity measurements and hardness is observed.

Bacterial infections affect about 1 in 5 patients who receive a dental implant within 5 years of surgery. To avoid the implant rejection it is necessary for the development of innovative biomaterials, with addition or substitution of the ions, for implant coatings that promote a strong bond with the new host bone and antibacterial action. The objective of this work was to synthesize a bioactive glass with different silver concentrations to evaluate their antibacterial performance. The glasses were synthesized with up to 2% silver content by melt-quenching. Structural, morphological, biological, and electrical properties of all samples were studied. The biological behavior was evaluated through cytotoxicity tests and antibacterial activity. The structural analysis shows that the introduction of silver do not promote significant changes, not altering the advantageous properties of the bioglass of the bioglass. It was verified that the glasses with a silver content from 0.5% to 2%, completely prevented the growth of both Staphylococcus aureus and Escherichia coli while being nontoxic toward mammalian cells. Therefore, these bioglasses are promising materials to be used in the production of dental implants with antimicrobial activity.

Electronic noses (E-noses), are usually composed by an array of sensors with different selectivities towards classes of VOCs (Volatile Organic Compounds). These devices have been applied to a variety of fields, including environmental protection, public safety, food and beverage industries, cosmetics, and clinical diagnostics. This work demonstrates that it is possible to classify eleven VOCs from different chemical classes using a single gas sensing biomaterial that changes its optical properties in the presence of VOCs. To accomplish this, an in-house built E-nose, tailor-made for the novel class of gas sensing biomaterials, was improved and combined with powerful machine learning techniques. The device comprises a delivery system, a detection system and a data acquisition and control system. It was designed to be stable, miniaturized and easy-to-handle. The data collected was pre-processed and features and curve fitting parameters were extracted from the original response. A recursive feature selection method was applied to select the best features, and then a Support Vector Machine classifier was implemented to distinguish the eleven distinct VOCs. The results show that the followed methodology allowed the classification of all the VOCs tested with 94.6% (± 0.9%) accuracy.

Truncated sialylated O-glycans, such as cell-surface carbohydrate antigen sialyl-Tn (STn) are overexpressed by several cancer types, but not by the respective normal tissues. STn expression is associated with oncogenesis and metastatic ability of cancer cells, with reduced overall survival and lack of response to chemotherapy. Advances in nanomedicine have resulted in rapid development of biocompatible superparamagnetic iron oxide nanoparticles (SPIONs) with considerable potential in cancer treatment. Therefore, in this study SPIONs coated with oleic acid (OA) or dimercaptosuccinic acid (DMSA) were developed and characterized for internalization in two breast cancer cell lines: cell line expressing the STn antigen and the corresponding control. SPIONs with an average diameter of 8 nm showed superparamagnetic behavior and high potential to be used as magnetic hyperthermia agents. OA and DMSA coating provided high stability of SPIONs in physiological conditions while not changing their main properties. NPs internalization studies showed a higher accumulation of DMSA coated NPs in the breast cancer MDA-MB-231 WT cell line. In MDA-MB-231 cell line expressing STn both coated NPs showed a similar accumulation. Therefore, STn antigen can act as a receptor capable of detecting and covalently bind to the molecules present on NPs surface and induce their cellular uptake by endocytosis.

In this work, eco-friendly magnesium-silicide (Mg2Si) semiconducting (n-type) thermoelectric pastes for building components concerning energy-harvesting devices through 3D printing, spray and electrospinning were synthetized and tested for the first time. The Mg2Si fine powders were obtained through the combination of ball milling and thermal annealing under Ar atmosphere. While the latter process was crucial for obtaining the desired Mg2Si phase, the ball milling was indispensable for homogenizing and reducing the grain size of the powders. The synthetized Mg2Si powders exhibited a large Seebeck coefficient of ~ 487 µV/K and were blended with a polymeric solution in different mass ratios to adjust the paste viscosity to the different requirements of 3D printing, electrospinning and low-pressure spray. The materials produced in every single stage of the paste synthesis were characterized by a variety of techniques that unequivocally prove their viability for producing thermoelectric parts and components. These can certainly trigger further research and development in green thermoelectric generators (TEGs) capable of adopting any form or shape with enhanced thermoelectric properties. These green TEGs are meant to compete with common toxic materials such as Bi2Te3, PbTe and CoSb that have Seebeck coefficients in the range of ~ 290–700 μV/K, similar to that of the produced Mg2Si powders and lower than that of 3D printed bulk Mg2Si pieces, measured to be ~ 4866 μV/K. Also, their measured thermal conductivities proved to be significantly lower (~ 0.2 W/mK) than that reported for Mg2Si (≥ 4 W/mK). However, it is herein demonstrated that such thermoelectric properties are not stable over time. Pressureless sintering proved to be indispensable, but difficultly achievable by long thermal annealing (even above 32 h) in inert atmosphere at 400 °C, at least for bulk Mg2Si pieces constituted by a mean grain size of 2–3 μm. Hence, for overcoming this sintering challenge and become the silicide’s extrusion viable in the production of bulk thermoelectric parts, alternative pressureless sintering methods will have to be further explored.

An unprecedented approach towards oligosaccharides containing N-acetylglucosamine-N-acetylmuramic (NAG-NAM) units was developed. These novel bacterial cell wall surrogates were obtained from chitosan via a top down approach involving both chemical and enzymatic reactions. The chemical modification of chitosan using a molecular clamp based strategy, allowed obtaining N-acetylglucosamine-N-acetylmuramic (NAG-NAM) containing oligomers. Intercalation of NAM residues was confirmed through the analysis of oligosaccharide fragments from enzymatic digestion and it was found that this route affords NAG-NAM containing oligosaccharides in 33% yield. These oligosaccharides mimic the carbohydrate basic skeleton of most bacterial cell surfaces. The oligosaccharides prepared are biologically relevant and will serve as a platform for further molecular recognition studies with different receptors and enzymes of both bacterial cell wall and innate immune system. This strategy combining both chemical modification and enzymatic digestion provides a novel and simple route for an easy access to bacterial cell wall fragments – biologically important targets.

Control of the properties of electrospun polycaprolactone can be achieved by adjusting the acetic acid:water ratio used to dissolve and electrospin the polymer. In this work, we studied the effect of using up to 15 wt% water in the solvent mixture. Solution conductivity and viscosity and fibre morphology vary dramatically with water content and solution age. Two days after initial solution preparation, electrospinning yields regular fibres for a water content of 0 wt% and 5 wt%, irregular fibres for a 10 wt% water content and irregular and fused fibres for a 15 wt% water content. Fibres with the highest crystallinity (60%) were obtained from solutions containing 5 wt% water while the highest elastic modulus (8.6 ± 1.4 MPa) and tensile stress (4.3 ± 0.3 MPa) pertain to fibres obtained from solutions containing 10 wt% water. Enzymatic fibre degradation is faster the higher the water content in the precursor solution. Adhesion ratio of human foetal fibroblasts was highest on scaffolds obtained from precursor solutions containing 0 wt% water. Cell population increases for all scaffolds and populations quickly become equivalent, with no statistically significant differences between them. Cells exhibit a more extended morphology on the 5 wt% scaffold and a more compact morphology on the 0 wt% scaffold. In summary, a small water content in the solvent allows a significant control over fibre diameter, scaffold properties and the production of scaffolds that support cell adhesion and proliferation. This strategy can be used in soft tissue engineering to influence cell behaviour and the degradation rate of the scaffolds.