Search Results (825)

Copper and its alloys are extensively employed in a broad range of industrial applications owing to their outstanding mechanical, electrical, and thermal properties. However, their susceptibility to corrosion in aggressive environments remains a major challenge, making corrosion inhibitors one of the most practical and cost-effective strategies for extending their service life. Nevertheless, conventional synthetic inhibitors are often limited by their high cost and adverse environmental and health impacts resulting from their toxicity. In this context, the present work provides a comprehensive experimental and theoretical assessment of the corrosion inhibition performance of Furosemide as an environmentally friendly inhibitor for copper in 3.5 wt.% NaCl solution. The corrosion inhibition performance was evaluated experimentally through gravimetric measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), while the adsorption behavior of Furosemide was investigated using density functional theory (DFT) calculations. The results demonstrated that expired Furosemide effectively reduced the corrosion rate of copper, with the inhibition efficiency increasing as the inhibitor concentration increased and decreased with increasing temperature. A maximum inhibition efficiency of 90% was achieved at an inhibitor concentration of 400 ppm. The calculated Gibbs free energy of adsorption indicated that Furosemide adsorbs onto the copper surface through a mixed physisorption–chemisorption mechanism, following the Langmuir adsorption isotherm. Potentiodynamic polarization measurements further revealed that Furosemide predominantly suppresses the anodic dissolution reaction, indicating that it behaves as an anodic-type corrosion inhibitor. In addition, the presence of Furosemide significantly decreased the passive current density and shifted the breakdown potential toward more positive values, demonstrating an enhancement in the stability and protective character of the passive film. Electrochemical impedance spectroscopy showed that the corrosion process was governed by diffusion-controlled kinetics in the uninhibited solution, whereas the addition of Furosemide changed the corrosion mechanism to a charge-transfer-controlled process. Density functional theory (DFT) calculations provided additional insight into the inhibition mechanism of Furosemide. The calculated E_HOMO) and E_LUMO values indicate that the molecule can both donate and accept electrons, reflecting its nucleophilic and electrophilic character and its strong affinity for adsorption on the copper surface. Furthermore, the relatively small energy gap (4.631 eV) suggests high molecular reactivity and facilitates electronic interactions with the metal surface. The estimated fraction of electrons transferred further supports the electron-donating ability of Furosemide during the adsorption process. Differences between the Fukui functions and the molecular electrostatic potential (MEP) maps are attributed to the distinct chemical information provided by each descriptor. Whereas the Fukui functions identify the most reactive atomic sites involved in soft donor–acceptor interactions, the MEP maps describe the molecular charge distribution governing electrostatic (hard–hard) interactions. Full article

The efficiency of cathodic protection in the tidal zone, in particular in its highest part, remains questionable. To address this problem, experimental vertical structures were designed and set in a commercial seaport. Each structure was composed of 10 cm × 10 cm carbon steel coupons and 50 cm × 10 cm carbon steel strips to obtain a 5.1 m long continuous structure extending all along the tidal zone. Cathodic protection of the structures was carried out with an Al-Zn-In galvanic anode permanently immersed in seawater. The mineral layers formed on the coupons after 32 and 52 months were analyzed by XRD and µ-Raman spectroscopy. The evolution of the mineral layer from the low water zone to the splash zone was due to (i) the decreasing efficiency of the cathodic protection and (ii) the changes in corrosion processes, from those typical of a permanent immersion to those typical of atmospheric corrosion. In particular, brucite Mg(OH)₂ was found up to the high tide zone and, in agreement with the estimated degradation of the coupons, its formation was an indicator of the altitude at which the cathodic protection remained efficient. Full article

Background: Pain affects 50–75% of individuals with multiple sclerosis (MS) and is more common than in the general population. Chronic pain is difficult to manage and may involve motor cortical and sensorimotor network alterations. Anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been explored as a neuromodulatory approach, although its effects and mechanisms remain unclear. Objective: This case series describes longitudinal changes in pain and anxiety following repeated anodal tDCS over left M1 in six individuals with MS-related chronic pain and descriptively reports concurrent changes in transcranial magnetic stimulation (TMS)-derived neurophysiological measures. Methods: Six adults with MS and chronic pain (≥4/10) received 1 mA anodal tDCS over M1 (10 min stimulation, 25 min interval, 10 min stimulation) in two 5-day blocks separated by 2 weeks (10 sessions total), with usual care maintained. Pain and anxiety (0–10) were assessed before and after sessions and at follow-up. TMS assessed corticospinal excitability and intracortical inhibition and facilitation at baseline, post blocks, and at follow-up. Results: Marked inter-individual variability was observed in clinical and neurophysiological trajectories following repeated anodal tDCS. Response patterns included immediate improvement after stimulation blocks, delayed improvement after the second block, and transient rebound during the inter-block interval. TMS-derived measures showed heterogeneous changes, with no consistent correspondence with clinical outcomes. Conclusions: This case series describes variable changes in pain, anxiety, and neurophysiological measures following repeated anodal tDCS over M1 in MS-related chronic pain. The findings are observational and highlight inter-individual variability, supporting further controlled studies. Full article

High lithium and manganese oxides (HLMs), also known as lithium- and manganese-rich oxides (LMR), are an alternative to the state-of-the-art (SoA) cathode materials for Li-ion battery cells due to their high specific capacity, working potential, and potential elimination of cobalt from their composition. Nevertheless, they are claimed to undergo accelerated capacity and potential fade. In this work, an extensive electrochemical characterization is conducted while revisiting the most relevant literature on HLM. The classical galvanostatic cycling is used to conduct differential voltage and incremental capacity analyses, while impedance spectroscopy and galvanostatic intermittent titration techniques are applied to complement this test. The results are complemented with online electrochemical mass spectrometry and postmortem characterization. Loss of anode active material is identified as the main degradation mechanism, aggravated by potential slippage. Moreover, the hypotheses on degradation mechanisms are further confirmed by changing the voltage cutoffs of the cells, limiting the Li₂MnO₃ activation. The results are benchmarked with SoA LiNi_0.8Mn_0.1Co_0.1O₂-based cells with a promising balance for HLM in some cases. This work serves as a guide to assist in the interpretation (and avoid misinterpretation) of the results with Li-ion batteries consisting of HLM electrodes. Full article

(1) Background: The effects of posterior parietal cortex (PPC)-targeted transcranial direct current stimulation (tDCS) on postural stability and cortical activity remain unclear. Therefore, this study aimed to investigate and compare changes in cortical activity and postural stability before and following tDCS conditions. (2) Methods: Eight right-handed adults completed a baseline assessment followed by three stimulation sessions: left-anodal/right-cathodal (L-A/R-C), left-cathodal/right-anodal (L-C/R-A), and sham on the PPC. The sessions were administered in a randomized Latin square design with a minimum 4-day washout period between each. At baseline and following each tDCS session, cortical activity was measured using functional near-infrared spectroscopy, and postural stability during a tandem stance was assessed utilizing the Balance Error Scoring System (BESS) and a force platform. (3) Results: Compared with the baseline measurements, significant deactivation in the right middle temporal gyrus (MTG) was observed following L-C/R-A stimulation. Furthermore, postural stability measures revealed significantly higher BESS error scores and greater sway length following L-C/R-A stimulation compared to both the baseline and L-A/R-C conditions. (4) Conclusions: Bilateral tDCS over the PPC differentially influences cortical activity and postural control depending on the stimulation polarity. Specifically, L-C/R-A stimulation was associated with impaired visual–vestibular integration and postural stability. These preliminary findings highlight the critical role of interhemispheric parietal balance in posture regulation and suggest that polarity-specific tDCS protocols may be important considerations for the future. Full article

Background/Objectives: While a growing number of studies have demonstrated positive effects of adjuvant anodal transcranial direct current stimulation (tDCS) on linguistic performance in aphasia, evidence for corresponding effects on verbal and—in particular—nonverbal functional communication remains absent. This is a critical gap, given that restoring everyday communicative competence is the ultimate goal of speech and language therapy (SLT). In the present observational study, we investigated the add-on effect of anodal tDCS over language-relevant left-hemispheric areas on verbal and nonverbal functional communication in n = 34 individuals with subacute aphasia and examined the relationship between communicative and linguistic change. Methods: Participants underwent two consecutive two-week therapy phases (P1, P2), each consisting of 10 SLT sessions. Severity-specific linguistic and communicative assessments were administered before, between, and after both phases: the Aachen Aphasia Test (AAT; n = 26) combined with the Amsterdam–Nijmegen Everyday Language Test (ANELT, A-scale), and the Bielefeld Aphasia Screening Rehabilitation (BIAS-R; n = 8) combined with the Scenario Test. During P2, SLT was supplemented by online anodal tDCS. Results: Overall test performance improved significantly more in tDCS-supported P2 compared to P1 (AAT profile level, p < 0.001; BIAS-R mean percentage value (MPW), p = 0.027; ANELT A-scale raw score Version 1, p = 0.081, and version 2, p = 0.038; and Scenario Test total score, p = 0.003). Significant correlations between AAT profile level and ANELT total scores were found across all time points. Between the MPV and subtests of the BIAS-R and the Scenario total score, there was a tendency toward decreasing correlation levels from T1 to T3. Conclusions: To our knowledge, this is the first study demonstrating that adjuvant tDCS in subacute aphasia enhances not only linguistic performance but also verbal and nonverbal functional communication beyond SLT alone—assessed with standardized, performance-based, ecologically valid instruments. Full article

6061 aluminum alloy is lightweight and has good thermal conductivity, while 304 stainless steel possesses excellent mechanical properties and corrosion resistance; both have broad application prospects in cooling circuits. Propylene glycol coolant shows great potential in liquid cooling systems due to its low toxicity and good antifreeze properties. However, during operation, galvanic corrosion may occur when the two metals come into direct contact within the coolant, thereby threatening system safety and service life. This study focuses on 6061 aluminum alloy, 304 stainless steel, and their galvanic couples. Electrochemical testing, SEM, 3D confocal microscopy, and XPS were used to systematically investigate their self-corrosion and galvanic corrosion behavior in propylene glycol coolant at pH values of 4.8, 6.8, and 8.8. The results indicate that 6061 aluminum alloy is more sensitive to pH changes; its corrosion resistance first increases and then decreases as pH rises, with the least corrosion occurring at pH = 6.8 and the most severe at pH = 4.8. 304 stainless steel exhibited lower corrosion rates at pH 6.8 and 8.8, but corrosion significantly worsened at pH 4.8. For the 6061 aluminum alloy/304 stainless steel couple, the galvanic current first decreased and then increased with rising pH, while the galvanic potential first increased and then decreased. The 6061 aluminum alloy consistently acted as the anode, and the 304 stainless steel consistently acted as the cathode, with the highest sensitivity to galvanic corrosion observed at pH 4.8. XPS analysis shows that under different pH conditions, the corrosion products of 6061 aluminum alloy are Al(OH)₃ and Al₂O₃, while the main components of the passivation film on 304 stainless steel remain unchanged. Full article

Aiming at non-uniformity in the vertical direction in the polishing effect on stainless steel after plasma electrolytic polishing (PEP), this paper took 304 L stainless steel as the research object. Under an ammonium sulfate electrolyte system with a mass fraction of 2.5 wt%, PEP was carried out utilizing different placement methods for the anode and electrolyte temperatures, and the causes of non-uniformity in the polishing process were explored. Experimental results demonstrate that the vertical polishing inhomogeneity originates from the upward movement of unruptured bubbles at the sample bottom. Under the combined effects of electrolyte internal pressure and bubble buoyancy, a vapor-gas envelope (VGE) featuring a thick upper part and thin lower part forms near the sample surface. This enhances plasma-related physicochemical reactions at the sample bottom and consequently raises the polishing rate. The vertical polishing unevenness can be alleviated by adjusting the electrolyte temperature. Non-uniformity could be improved by controlling the temperature of the electrolyte. Compared with the result at 95 °C, the maximum dimensional variation in each region on the sample at 75 °C was reduced by 36% because a VGE with more uniform thickness was formed, and a properly oxidized sparse layer helped protect the substrate from ablation and over-polishing. In addition, the removal rate of elements on the surface of stainless steel is affected by its activity due to the oxidation reaction. The high removal amount in the bottom region caused a trend of increasing Cr and decreasing Fe content percentages from the top to the bottom on the stainless-steel surface. However, the oxidation removal rate of elements is extremely fast due to the high temperature of the ionization center and strong electric field; therefore, the content percentage of each element on the surface is little changed after polishing. Full article

Background/Objectives: To summarize evidence on whether anodization of titanium implant abutments modifies abutment surface/physical properties, peri-implant soft tissue esthetics, and biological outcomes compared with machined titanium and alternative abutment materials. Methods: This focused narrative review used a structured, reproducible literature search with dual-reviewer screening and data extraction. The study selection pathway was summarized using a PRISMA-style flow diagram for transparency. Searches of PubMed/MEDLINE, EMBASE, CENTRAL, and Google Scholar were performed, supplemented by gray literature screening and manual searching. Laboratory, animal, and human clinical studies evaluating anodized titanium abutments were eligible. Data were synthesized qualitatively across prespecified domains (surface or physical properties, esthetic outcomes, and biological outcomes). Because the work was designed as a narrative review, protocol registration and formal risk of bias appraisal were not undertaken. Results: Thirty-five studies were included (twenty-five in vitro, three animal, and seven human clinical). Anodization modified oxide layer characteristics and surface chemistry, and was commonly associated with increased hydrophilicity. Esthetically, pink or yellow anodized titanium generally reduced discoloration compared with uncolored titanium, particularly when soft tissue and restorative material thickness were sufficient, whereas zirconia most consistently produced the most favorable color outcomes. In vitro studies frequently reported improved early soft tissue cell responses and, in selected protocols, reduced bacterial adhesion. Reported clinical differences in inflammation indices and peri-implant marginal bone changes were small or inconsistent. Conclusions: Anodization can improve the optical masking of titanium and alter surface wettability and chemistry, but evidence for sustained clinical biological benefit remains limited. Current evidence supports anodization primarily as an esthetic adjunct, while long-term peri-implant biological outcomes appear to be driven by multiple clinical factors beyond surface modification. Full article

A biogenic ZnO/Ag photoelectrode treated with atmospheric-pressure plasma was evaluated as an anode in a photo-assisted electroflotation system for the transformation of chromophoric pollutants in real industrial wastewater. ZnO was synthesized from Azadirachta indica leaf extract and plasma-treated for 10 min (M2) and 15 min (M3), with an untreated reference (M1). XRD, SEM-EDS, Raman, FTIR, EPR, and XPS analyses showed that the plasma preserved the wurtzite structure, relaxed the bulk, and modified the surface by removing residues, deoxygenating it, and activating oxygen vacancies (V_O). Although M3 reached the highest deoxygenation, M2 showed the most favorable response; thus, the performance did not depend only on the total amount of V_O. Under dark conditions, M2 showed a 14.86 percent decrease in COD compared to the control in a single batch and had the most negative ORP value. However, only ORP came close to statistical significance after multiplicity correction, with p_adj = 0.055. Under illumination, it showed the strongest photoinduced changes in conductivity and total suspended solids. The light–dark differences (ΔL−O) showed sign reversals in COD, conductivity, and pH, which identified three functional regimes and indicated that the electronic coupling of the surface V_O, rather than its amount, controlled the performance. ΔL−O was proposed as an operational test to distinguish these regimes, with the plasma exposure time as a key control variable. Because the effluent responses were single determinations, they are considered exploratory; the mechanism is primarily based on structural and spectroscopic characterization and supported by photoelectrochemical tests. Full article

In this study, hexagonal titanium dioxide nanotubes (hTNTs) fabricated by sonoelectrochemical anodization were thermally modified in air to investigate the influence of annealing temperature and heating/cooling rate on phase evolution, structural stability and electrochemical behavior. The samples were annealed at 450 °C, 550 °C, and 650 °C for 2 h using heating/cooling rates of 6 °C/min, 10 °C/min, and 20 °C/min. The hexagonal nanotubular morphology remained preserved after thermal treatment. However, increasing annealing temperature and heating/cooling rate promoted crack formation due to the thermally induced stress relaxation and phase transformation. The anatase content increased with increasing heating/cooling rate, indicating kinetically limited anatase-to-rutile transformation, whereas annealing at 650 °C promoted partial rutile formation. Electrochemical studies demonstrated that annealing temperature and heating/cooling rate affected the electrochemical behavior of hTNTs through different mechanisms. Increasing annealing temperature promoted structural ordering and partial anatase-to-rutile transformation, leading to reduced current response and enhanced electrochemical stability. In contrast, heating/cooling rate significantly affected impedance behavior and diffusion-related processes, indicating changes in charge transfer kinetics and ion transport within the nanotubular oxide layer. The results demonstrate that thermal treatment kinetics play an important role in controlling the phase composition and electrochemical behavior of hTNTs, providing insight into the thermal optimization of hexagonal TiO₂ nanotubes for advanced functional applications. Full article

A pyranochromene-based ligand, 2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (ACLPh-PC-3-CN), was employed as a chelating modifier for the electrochemical determination of Cd(II) in water samples. ACLPh-PC-3-CN was co-immobilized with Nafion on a glassy carbon electrode to form a stable ACLPh-PC-3-CN/Nafion film that combines ligand-based coordination with cation-exchange-assisted preconcentration of Cd²⁺ at the electrode surface. The Cd(II) response at the modified electrode was characterized by cyclic voltammetry and differential pulse anodic stripping voltammetry, and the data support a predominantly 1:1 Cd(II)–ligand interaction at the interface under the selected conditions. At an optimized pH of 6.0, the sensor provided a linear calibration range from 16.21 to 56.72 μM, with a detection limit of 0.60 μM and a quantification limit of 2.0 μM, and showed good precision (repeatability 2.3% RSD, reproducibility 3.1% RSD) and short-term stability (94% of the initial response after 14 days). The ACLPh-PC-3-CN/Nafion-modified electrode tolerated common inorganic ions and surfactant species (≤5% signal change) and was successfully applied to the determination of Cd(II) in tap water and Red Sea water, affording recoveries between 98.7% and 101%. While the current detection limit is higher than typical guideline values for Cd in drinking water, the proposed sensor compares favorably with several reported electrochemical Cd(II) sensors in terms of simplicity, precision, and matrix tolerance, and represents a useful platform for coordination-based electrochemical sensing of cadmium in environmental water samples. Full article

Graphite is widely used as an anode in lithium-ion batteries (LIBs); however, its limited capacity restricts the energy density enhancement. Si-based anodes offer much higher capacity, but their significant volume changes during repeated lithiation and delithiation generate mechanical stress and can damage the electrode/current-collector interface. Herein, high-strength nanotwinned Cu (NT-Cu) was fabricated and employed as current collectors for carbon-coated Si/β-Si₃N₄-based anodes. The electroplated 5 μm-thick NT-Cu foils exhibited tensile strength exceeding 760 MPa. The role of the Cu current collector was investigated by comparing NT-Cu foils with different mechanical properties and commercial Cu foils. The results show that electrochemical performance was not governed by UTS alone; instead, a balanced combination of tensile strength, ductility, and surface morphology was important for improving cycling stability and rate capability. To further improve cycling retention, artificial graphite was incorporated into the Si/β-Si₃N₄ composite. Using a 5 μm electroplated NT-Cu foil and a Si/β-Si₃N₄/artificial graphite composite anode, the pouch cell retained 81.51% of its capacity and delivered 267.3 mAh g⁻¹ after 206 cycles. These results demonstrate the potential of NT-Cu for improving the stability of Si-containing LIB anodes. Full article

High-nickel NCA/Si–C 21700 cells exhibit strongly condition-dependent degradation, but the coupled influence of temperature and rate on electrochemical, thermal, and structural evolution remains insufficiently resolved. Here, Samsung INR21700-50E cells were aged under a 3 × 3 matrix of ambient temperatures (0, 23, and 40 °C) and C-rates (0.5C, 1C, and 2C). Periodic reference performance tests were used to track capacity, 10 s direct-current internal resistance, electrochemical impedance, pseudo-open-circuit voltage, differential voltage/incremental capacity behavior, heat generation, and post-mortem morphology. Guided by the hypothesis that temperature and rate history change not only the speed but also the dominant pathway of aging, the results show that both ambient temperature and the charge/discharge rate program govern the aging trajectory. Low-temperature cycling accelerates capacity loss and resistance growth through severe polarization and lithium plating, indicating dominant loss of lithium inventory. High-temperature operation promotes interfacial side reactions, impedance rise, and cathode structural degradation, leading to stronger loss of active material at later stages. An increasing C-rate amplifies these effects by raising overpotential and thermal load. Heat generation power increases markedly with aging and depends strongly on temperature–rate history. Scanning electron microscopy confirms cathode cracking, anode surface film thickening, and separator degradation under severe conditions. These experimental indicators are integrated into a mechanism-aware diagnostic framework that maps capacity retention, DCIR/EIS parameters, ICA/DVA indices, and heat generation metrics to dominant aging modes, supporting BMS state-of-health estimation, lifetime prediction, thermal management, and second-life screening of high-nickel NCA cells. The condition-averaged trajectories are further converted into a semi-empirical aging law that links capacity loss, resistance growth, and heat generation increase for BMS-oriented lifetime prediction. Full article

Anaerobic digesters (ADs) are widely used for the recovery of energy from biomass waste, while performance deterioration of ADs sometimes occurs under high organic loads. Microbial electrolysis cells (MECs) have been examined for incorporation into ADs to improve methane production, while responses of MEC-assisted ADs (MEC-ADs) to changes in operational conditions have yet to be sufficiently examined. Here we operated laboratory ADs and MEC-ADs with food waste as a feed, and organic loading rates (OLRs) were varied by changing hydraulic residence times (HRTs). Analyses of AD performances, including methane production and chemical oxygen demand (COD) removal, show that MEC-ADs exhibit higher performances than ADs at OLRs of 7 g COD L⁻¹ D⁻¹ or higher (HRT of 10 days or less). In addition, pH was stably maintained in MEC-ADs at high OLRs. Metabarcoding of rRNA gene amplicons showed that Desulfuromonadaceae bacteria were enriched at the anodes in MEC-ADs, while Methanobacteriaceae archaea were increased at the cathodes. It is suggested that the MEC system is useful for stably operating ADs at high OLRs and/or short HRTs. Full article