In this study, a series of rare-earth trimesates (REBTC, where RE3+ = La–Nd, Gd, Lu, and BTC3− = benzene-1,3,5-tricarboxylate, C6H3(COO−)3) was investigated for the removal of toxic Pb2+ ions from wastewater. The development of effective metal-organic frameworks (MOFs) for this purpose is an important challenge in environmental and materials science. The phase composition, crystal structure, and morphology of the samples have been characterized by powder X-ray diffraction, IR spectroscopy, TGA/DSC, and SEM. It has been established that the size of microcrystals has a decisive effect on the Pb2+ adsorption capacity. The LaBTC sample, with the composition [La(BTC)(H2O)6], the REBTC (Cc) structure type, and the smallest microcrystals, exhibited the best sorption performance, with a maximum adsorption capacity of 166.61 μmol/g, approximately 3–4 times that of GdBTC and LuBTC, which had larger microcrystals.
The Ti6Al4V alloy is widely used for biomedical implants, but the long-term stability of its surface in physiological environments can be improved by applying phosphate conversion coatings. In this study, three multicomponent coatings—Zn-Zr-Mg, Mg-Zn-Zr, and Zr-Zn-Mg—deposited on Ti64 were investigated to examine the influence of exposure time, coating composition, and immersion medium on electrochemical behaviour. The samples were immersed for 30, 60 and 90 days in Ringer’s solution, DPBS and EBSS, and their electrochemical stability was assessed using electrochemical impedance spectroscopy and equivalent circuit modelling. The results showed a trend that depended on both the layer composition and the test environment, with no steady decrease in impedance over time. After 90 days, the coated specimens retained low-frequency impedance moduli on the order of 104–105 Ω·cm2, depending on coating composition and immersion medium. In Ringer’s solution, the highest 90-day response was obtained for Zr-Zn-Mg, with
This work proposes the study of light-sensitive resistive sensors composed of dispersed heterojunctions (BHJs) in a poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) matrix, fabricated from cobalt and palladium porphyrins (CoOEP and PdOEP), and mixed with ethylanthraquinone (EAQ). Topographical characterization was performed using atomic force microscopy. In addition, the BHJs were characterized by their transmittance and fluorescence, and their band gap of 3.6 eV was similar for both heterojunctions and independent of the metal in the porphyrin. However, transmittance and fluorescence are more strongly correlated with the metal of the macrocycle. With PdOEP-EAQ/PEDOT:PSS and CoOEP-EAQ/PEDOT:PSS films as active layers, sensitive resistive sensors were fabricated and optimized by embedding SnO2 and ZnO nanoparticles in PEDOT:PSS, as well as aluminum hydroxyquinoline, within the same polymer matrix. The devices fabricated on Tetra Pak and glass substrates were electrically characterized over a voltage range of −1.1 to 1.1 V under both white illumination and darkness. The results show that glass devices deposited with SnO2-PEDOT:PSS and ZnO-PEDOT:PSS exhibit improved linearity of electrical conduction under dark conditions. Furthermore, for the SnO2-PEDOT:PSS/CoOEP-EAQ device, the electron mobility and free carrier density were estimated, yielding values of μn=2.495×10−3cm2Vs and n0=8.69×10201cm3, respectively. The manufactured devices exhibited a light-dependent resistive response, suggesting their suitability for light-sensing applications.
This study investigates the correlations between the parameters of the Hysteresis-Attrition-Friction model (HAF), hysteresis (h), attrition (a), and friction coefficient (ν), under different surface conditions and contact pressures. The HAF model, a sigmoidal model developed in-house, provides a novel approach for characterizing tribological behaviour through its three key parameters (h, a, ν). The analysis employed a bootstrapping method to generate numerous parameter samples, allowing for the estimation of joint distributions and the identification of correlations between parameter pairs. The model here is applied to data from experiments conducted using both smooth and rough surface configurations at three distinct contact pressures: 1.2 GPa, 1.6 GPa, and 1.9 GPa. The results revealed a positive correlation between hysteresis and attrition across both surface types, indicating that higher energy dissipation through hysteresis is associated with increased friction. Conversely, negative correlations were found between hysteresis and friction coefficient, and between attrition and friction, suggesting a trade-off between energy dissipation and friction. The bivariate kernel density plots further highlighted these patterns, helping to visualize the complex relationships within the model. The results emphasize the importance of considering surface conditions and pressure when applying the HAF model to predict performance in tribological systems.
Binary surfactant formulations can modify thin-film stability through non-additive changes in adsorption, interfacial mobility, and surface rheology. This study extends an electrical liquid-bridge method previously developed for single surfactants to binary systems containing sodium dodecyl sulfate (SDS), benzalkonium chloride (BAC), Ethylan 1005, sodium oleate, and polypropylene glycol 600 (PPG 600). Sixteen formulations were examined at fixed drainage rates of 10 and 20 µL h−1 using normalized apparent-conductance measurements synchronized with optical recording and TechDig contour reconstruction. Fifteen formulations formed measurable films at both rates, whereas 250 ppm SDS + 500 ppm sodium oleate (nominal mass–concentration ratio 1:2) failed by neck rupture before film formation. Binary mixtures either prolonged film lifetime relative to matched single-component references or enabled film formation where the reference was non-film-forming. Optical measurements independently supported the electrical ranking: longer-lived films generally reached smaller terminal neck diameters. The longest-lived formulation, 3000 ppm SDS + 500 ppm sodium oleate, also reached the smallest terminal neck. Pump-based mass balance and terminal bubble deformation further supported greater liquid removal and axial stretching before rupture. The combined electrical–optical approach provides a reproducible comparative framework for composition-dependent thin-film stabilization.
