Search Results (212)

This paper investigates the effects of dissolved oxygen and an amino acid corrosion inhibitor on the corrosion of 20# carbon steel in tap water and deionized water. The corrosion behavior was systematically analyzed using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, weight loss measurements, and scanning electron microscopy (SEM). The results show that deoxygenation is the most effective way to inhibit the carbon steel corrosion in two media, and the increase in dissolved oxygen concentration will make the carbon steel in the tap water corrosion resistance decline, but additional oxygen will enhance its corrosion resistance compared with the natural state without deoxygenation and oxygen addition in deionized water. Moreover, the effectiveness of the corrosion inhibitor in inhibiting carbon steel corrosion in tap water is significantly lower than that in deionized water. These results offer valuable insights for the operation of carbon steel firewater pipelines in media containing dissolved oxygen and serve as a practical guide to enhancing their service life. Full article

Ball milling treatment facilitates the transformation of carbonyl iron powders from a spherical to a flaky morphology, while simultaneously introducing numerous defects that approach the nanometer scale in one dimension. Flaky iron nitride was synthesized via the gas nitridation in an NH₃/N₂ atmosphere. The microstructure, morphology, and magnetic properties of the samples nitrided at different temperatures were characterized using XRD, SEM, TEM, and VSM. The formation of γ′-Fe₄N and ε-Fe₃N phases impedes domain wall movement, resulting in a slight increase in the H_c of the samples. Notably, γ′-Fe₄N positively influences the magnetic properties of iron nitride. As the nitriding temperature rises, the content of the γ′-Fe₄N phase initially increases before subsequently declining. Consequently, the flaky iron nitride synthesized at 610 °C exhibits excellent soft magnetic properties with a high M_s value reaching up to 177.1 emu/g and a low H_c value, indicating its potential applications in the field of magnetic materials. Full article

Perovskite solar cells (PSCs) are promising photovoltaic technologies, yet their performance is critically influenced by the relative permittivity (ε_r) of the active layer, which governs charge carrier dynamics. This study employs SCAPS-1D simulations coupled with complex impedance and modulus spectroscopy to systematically investigate the impact of varying the ε_r of the MAPbI₃ layer from 4 to 12. We find that while the open-circuit voltage (V_oc~1.05 V) and short-circuit current density (J_sc~25 mA cm⁻²) remain stable, the FF and efficiency η (%) decline from 78% to 70% and 20% to 17%, respectively, with increasing εr. Impedance analysis deconvoluted this trend, revealing a decrease in recombination time (τ₁) and a peak in ionic transport time (τ₂) at ε_r = 7. The optimal performance of 18.86% was achieved at a lower ε_r, demonstrating that minimizing recombination losses through permittivity engineering is crucial for advancing PSC efficiency. Full article

This study evaluated the efficacy of an environmentally friendly degreasing agent formulated from orange peel extract as both a cleaning agent and corrosion inhibitor for surgical instruments manufactured from 316LVM stainless steel. The extract was obtained via microwave-assisted hydrodistillation and subsequently blended with biodegradable surfactants. Its performance was compared against a benchmark commercial cleaner (West Oxyclean^®) through Tafel polarization, Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). FTIR analysis confirmed the presence of terpenic compounds, predominantly limonene, alongside ethers, alcohols, and unsaturated structure characteristics of citrus essential oils. Polarization and EIS results showed that the formulation containing 0.12% extract exhibited the highest charge-transfer resistance and the lowest corrosion current density (0.093 μA/cm²), achieving an inhibition efficiency of 81.29%, whereas the 0.08% formulation showed greater corrosive response than the commercial cleaner. SEM imaging demonstrated a progressive decline in both the severity and density of localized corrosion attacks with increasing extract concentration, while XRD diffractograms indicated a marked reduction in corrosion-product formation—completely absent at the optimal concentration. These findings demonstrate that orange peel extract functions as an effective and environmentally sustainable corrosion inhibitor, capable of preserving the structural and surface integrity of surgical-grade steel. Its technical performance, combined with its biodegradable profile, positions it as a promising alternative to conventional industrial cleaners within medical and hospital applications. Full article

Background/Objectives: Assessing age-related health decline in the elderly is critical, yet standard metrics like Body Mass Index (BMI) can be misleading. Bioelectrical impedance analysis (BIA) is a popular method to assess body composition. This study evaluated the relationship between BIA-derived parameters, a comprehensive panel of laboratory biomarkers, and nutritional status in a cohort of Polish older adults. Methods: In a cross-sectional study of 126 elderly participants (106 women, 20 men; mean age: 72.4 years), we performed multi-frequency segmental BIA to measure fat-free mass, skeletal muscle mass, and phase angle (PA). Nutritional status was assessed using the Mini Nutritional Assessment (MNA). Venous blood samples were analyzed for a comprehensive panel of hematological, inflammatory (CRP), hormonal (leptin), and metabolic biomarkers. Results: The analysis characterized the body composition and biomarker profiles of the cohort. MNA-defined malnutrition risk was associated with significantly lower muscle mass and PA, and altered fluid distribution (higher extracellular-to-total body water ratio), but not with reduced fat mass. Adiposity correlated strongly with leptin and CRP. Hematological parameters were linked to lean mass, while zinc and albumin correlated with PA. Canonical analysis identified two distinct physiological axes: a dominant “adipo-hormonal” axis linking leptin to fat mass, and a secondary “metabolic–cellular integrity” axis linking zinc and iron status to Phase Angle and fluid balance. Conclusions: In older adults, nutritional risk is characterized by sarcopenia and fluid shifts, not low adiposity, highlighting the inadequacy of BMI. BIA parameters, especially the phase angle, may serve as promising indicators of cellular health that correlate strongly with key micronutrients, suggesting a potential role in complementary geriatric assessment. Full article

Background: Institutionalized older adults often experience cognitive and functional decline and altered body composition (BC), making nutritional assessment difficult. Bioelectrical impedance analysis (BIA) offers a simple and non-invasive method to evaluate BC; classic and specific bioelectrical impedance vector analysis do not require predictive models or assumptions about hydration status. Objective: This study aimed to evaluate the utility of BIA, classic bioelectrical impedance vector analysis (BIVA), and specific BIVA (BIVA-Sp) in detecting nutritional and other related disorders in institutionalized psychogeriatric patients. Methods: A cross-sectional study was conducted in 95 institutionalized older adults (52 men, 43 women; mean age: 80 years). Clinical and functional data, including frailty, dependency, handgrip strength, and anthropometry, were collected. BC was assessed using BIA. Nutritional diagnoses included malnutrition (GLIM criteria), sarcopenia (EWGSOP2), adiposity, and sarcopenic obesity (SOGLI criteria). Mean impedance vectors and 95% confidence ellipses were generated for BIVA and BIVA-Sp. Individual vectors were compared with reference data from healthy older adults. Statistical analyses compared clinical variables and impedance vector distributions between groups. Results: Classic BIVA differentiated patients with sarcopenia and sarcopenic obesity, while BIVA-Sp identified vector shifts associated with adiposity and sarcopenic obesity. Neither BIVA nor BIVA-Sp discriminated patients based on body mass index or malnutrition status. Conclusions: The application of BIVA in institutionalized psychogeriatric patients allows for easier, faster, and more effective detection of changes in BC and hydration status compared with conventional methods. This enables individualized monitoring and facilitates interventions that may reduce complications, functional decline, and hospitalizations, thereby improving their quality of life. Full article

X80 pipeline steel is a key material in the field of oil and gas transportation. Its damage behavior in a hydrogen-filled environment directly affects pipeline safety. In this study, through hydrogen permeation experiments and slow strain rate tensile tests, the electrochemical responses and hydrogen-induced cracking behaviors of X80 base metal and welded joints under hydrogen filling conditions in both AC and DC were systematically compared. The results show that when the base material is filled with hydrogen at 20 mA/cm² AC, the hydrogen permeation flux is the largest, and the overall hydrogen permeation parameter of the welded joint is lower than that of the base material. High-frequency polarization promotes hydrogen permeation, but anodic corrosion products at high current densities can impede hydrogen entry. The slow strain rate tensile test further confirmed that the mechanical properties of the material declined more significantly under direct current hydrogen charging, and the sensitivity to stress corrosion cracking was higher. Under alternating hydrogen charging conditions, due to the alternating effects of hydrogen charging at the cathode and corrosion at the anode, a relatively low hydrogen embrittlement sensitivity is exhibited. Full article

A hollow fiber-supported polymeric mixed-matrix membrane, consisting of a Pebax-1657 matrix and graphene nanoplatelet (GNP) fillers as the selective layer, was tested for CO₂/CH₄ gas separation at transmembrane pressures up to 30 bar(a). Using a custom, novel, membrane module, we simultaneously performed permeability/selectivity and in situ electric impedance spectroscopy measurements. This in situ technique is proposed here for the first time. Furthermore, stable mixed-gas selectivities, for 10% CO₂ in CH₄ gas, reaching up to 61.4 (M0) and 68.5 after heat treatment (M2) were observed at 20–30 bar(a), whereas the stressed state (M1) dropped to ~22. Throughout the whole procedure of the three (initial, degraded, and restored) membrane testing assessments, a gradual decline in gas permeability coupled with a corresponding increase in the membrane’s AC resistance, due to membrane compaction, was evident. More specific, the membrane’s AC resistance, R₁, increased from ~96–147 ΜΩ (M0) to ~402–435 ΜΩ (M1) and ~5390–5700 ΜΩ (M2), while the peak-phase frequency f_p decreased from ~1.25 kHz (M0) to ~340 Hz (M1) and ~115 Hz (M2). Overall, this work proposes a new tool/method for connecting membrane’s deterioration phenomena with AC resistance and demonstrates that a facile heat treatment can restore selectivity following compaction, despite the absence of full permeance recovery. Full article

Cities are major sources of anthropogenic carbon dioxide (CO₂) emissions, making the study of intra-urban CO₂ concentration patterns an emerging research priority. However, limited data availability and the complexity of urban environments have impeded detailed spatiotemporal analyses at the city scale. To address these challenges, an analysis supported by multi-source data and GeoAI methods is carried out to examine the spatial distribution, vertical variation, temporal dynamics, and driving factors of CO₂ concentrations in urban areas. We combined OCO-2 satellite-derived XCO₂ data (2014–2024) with ground-based measurements from the Shanghai Tower (August 2024 to March 2025), alongside meteorological and socioeconomic variables. The analysis employed spatial interpolation (inverse distance weighting), nonparametric testing (Mann–Whitney U test), time series decomposition, ordinary least squares (OLS) regression, and machine learning techniques including random forest and SHAP (SHapley Additive exPlanations) analysis. Results reveal that CO₂ concentrations are significantly higher in central urban districts compared to suburban areas, with notable spatial heterogeneity. Elevated levels were detected near ports and ferry routes, with airports and industrial emissions identified as principal contributors. Vertically, CO₂ concentrations decline with increasing altitude but exhibit a peak at mid-level heights. Temporally, a pronounced seasonal pattern was observed, characterized by higher concentrations in winter and lower levels in summer. Both OLS regression and machine learning models highlight proximity to emission sources, wind speed, and temperature as key determinants of spatial CO₂ variability, with these factors collectively explaining 67% of the variance in OLS models. This study demonstrates how multi-source data and advanced methods can capture the spatial, vertical, and seasonal dynamics and driving factors of urban CO₂ concentrations, offering insights for policy, planning, and mitigation. Full article

Impedance biosensors are manufactured on glass slides using a semiconductor process to monitor cell growth and cell–drug reactions in real time, and the results are compared with biological assay results to confirm the validity of impedance measurement method. Approximately 10,000 cells per well were cultured for 48 h, after which 6.67 μg/mL puromycin was injected to observe apoptosis over the following 48 h. A frequency sweep from 1 kHz to 1 MHz was performed to determine the optimal frequency range, identifying 367–440 kHz as the most sensitive for detecting impedance changes. Impedance was measured every 10 min for 96 h. Capacitance gradually increased during cell proliferation, while after drug administration, a transient increase occurred within 9 h, followed by a rapid decline, indicating cell death within 24 h. The sensor utilized Electrical Cell–substrate Impedance Sensing (ECIS) to detect real-time changes in cell status without the need for staining or destruction. Comparison with conventional biological assays such as MTS and FACS confirmed that the impedance biosensor provided higher sensitivity and quantitative accuracy in monitoring both cell proliferation and apoptosis. This study demonstrates that the developed biosensor enables label-free, non-invasive, and continuous monitoring of cellular behaviors with acceptable coincidence with 3 different biological assay results. Impedance biosensor presents a promising alternative to conventional biological assays and offers potential applications in drug screening, cytotoxicity evaluation, and real-time biological monitoring. Full article

Background and Objectives: This study aimed to compare acute changes in body composition parameters following marathon (42.195 km) and ultramarathon (61 km) runs in trained male athletes, with particular focus on hydration dynamics and metabolic stress. Materials and Methods: Sixteen male amateur endurance runners were assigned to two groups: marathon (n = 8) and ultramarathon (n = 8). Body composition was assessed at three time points pre-race, immediately post-race, and 24 h post-race using bioelectrical impedance analysis. Measurements included body weight (BW), body mass index (BMI), total body water (TBW), total body fat (TBF), lean body mass (LBM), right arm fat (RAF), left arm fat (LAF), right leg fat (RLF), left leg fat (LLF), and torso fat (TF). Results: Both groups exhibited significant reductions in BW and BMI post-race (p < 0.05), with more pronounced changes observed in the ultramarathon group. Partial restoration of these metrics occurred within 24 h, primarily due to glycogen resynthesis and fluid retention. TBW remained stable immediately post-race but increased notably during recovery, particularly in ultramarathon runners, suggesting more effective hydration responses. Muscle and fat-free mass changes were minimal but more favorable in the ultramarathon group. Both total and regional fat percentages declined significantly post-race in both groups, with ultramarathon runners showing greater reductions. Conclusions: Endurance running induces short-term but substantial alterations in body composition, with ultramarathon participation eliciting more pronounced metabolic and fluid balance responses. These findings highlight the importance of race-specific nutritional and hydration strategies tailored to event type and duration. Full article

The analysis of rainfall-induced landslides, which involve complex interactions between hydrology, soil mechanics, and geometry, is still limited by simplifying assumptions in existing models. We introduced a numerical model that couples soil infiltration with three-dimensional (3D) slope stability analysis. After validating against benchmark problems, we used this model to investigate the effects of various hydro-geotechnical conditions on slope stability. The results show that rainfall intensity dictates the stability of shallow landslides, while for deep-seated landslides, it governs the rate of progression toward failure. A high initial groundwater table reduces slope stability by accelerating soil weakening, particularly for deep landslides. Although upward moisture redistribution via matric suction is possible, its effect is negligible during infiltration, allowing deep saturation and landslide risk to persist. Furthermore, a low-permeability basal layer impedes drainage, leading to pore pressure buildup and a rapid decline in stability. The proposed model could potentially overcome the limitations in predictive accuracy of current hydro-geotechnical models arising from their oversimplified representations. Full article

With the increasing adoption of lithium-ion batteries (LIBs) as the batteries of choice in electromobility, personal electronic devices, and so on, comes the challenge of ageing, which prevents the batteries from performing optimally and meeting the design intent. This is observed in the form of declining power capability due to the increase in resistance and the reduction in capacity that can be stored or discharged from them. Unfortunately, the cost of assessing batteries after the first use remains a daunting challenge. In our work, we propose an approach that carries out fast preliminary grading based on resistance and capacity by first connecting old cells of the same chemistry and model in series with resistors to limit the branch current, then connecting the branches in parallel to equalise the voltages. A Simulink model of NCR18650PF Panasonic cells with adaptive-series resistance is compared with a fixed-series resistance and found to improve the balancing time from over 24 h to just 8 h. Electrochemical impedance spectroscopy (EIS) was carried out on the individual balanced cells between 0.1 Hz and 5 kHz so that the real impedance, imaginary impedance, absolute impedance, and phase were compared with the SOH of the cells at each frequency. Results show that the imaginary impedance in the 6.6 Hz frequency range shows a good correlation coefficient > 0.98 with the SOH, especially with a state of charge (SOC) of about 75–85% for the LCO cells. By selecting only a sample from all the cells that covers a wide range of ages and carrying out a full-capacity checkup on them, a simple correlation with the SOH and the EIS measurements for different frequencies can be used to estimate the SOH of the other cells that were connected in the same parallel connection. This is a considerable time saving in the charge and discharge time on the other cells in facilities that lack the capacity for simultaneous cycling of all cells. There are also huge energy savings in not having to cycle all the cells. Therefore, it offers a more efficient approach to grading spent cells than carrying out full capacity tests. Full article

This study investigates the effect of γ-aminopropyltriethoxysilane (KH550)-functionalized nano-active Al₂O₃ (KH-Al) on the properties of gypsum-based self-leveling mortar (GSL) prepared from industrial by-product gypsum. First, the effects of incorporating KH-Al at dosages of 0.05%, 0.1%, 0.25%, 0.5%, and 1% on the fluidity, setting time, and mechanical properties of GSL were analyzed. Subsequently, using X-ray diffraction (XRD), hydration heat analysis, thermogravimetric analysis (TG), and scanning electron microscopy (SEM), the influences of the nanomaterial on the mortar’s morphology, hydration characteristics, and crystal forms of hydration products were thoroughly examined. Finally, by comparing the modified GSL with ordinary GSL, the mechanism of KH-Al’s action on GSL was elucidated. The results demonstrate that nano-active Al₂O₃ modified with KH550 exhibits excellent dispersibility in the GSL paste. As the dosage of KH-Al increases, both the fluidity and setting time of GSL decrease. Upon incorporating KH-Al, the mechanical properties of GSL initially improve and then decline, with optimal mechanical performance observed at a 0.5% KH-Al addition. However, when the KH-Al dosage exceeds 0.5%, excess nano-active Al₂O₃ causes nanoparticle agglomeration, which impedes the hydration process. The nucleation effect of KH-Al promotes the formation of CŜH₂ and AFt, refines the crystals of hydration products, and enhances the phase transformation efficiency of the mortar. These findings indicate that KH-Al has significant potential to improve the mechanical strength and hydration kinetics of gypsum mortar and provide theoretical support for the application of nanomaterials in gypsum building materials. Full article

Background/Objectives: Nutritional disorders are common conditions in older people. This study aimed to determine nutritional disorders in a Mediterranean cohort of nursing home residents without cognitive or functional impairment. Methods: A multicentre cross-sectional observational study was conducted in 10 Spanish geriatric centres. Socio-health, clinical, and laboratory data were recorded from the participants’ medical records. The Mini-Nutritional Assessment (MNA) and Global Leadership Initiative in Nutrition (GLIM) diagnostic criteria [weight loss and serum C-reactive protein (CRP)] were used. Frailty risk was assessed using the FRAIL questionnaire. Anthropometric parameters [body mass index, weight loss, triceps skinfold thickness (TSF), muscle mass circumference (MAMC), and calf-circumference] were evaluated. Body composition [hydration pattern, fat-free mass, muscle mass (MM), fat mass, and phase angle (PhA)] was measured by bioelectrical impedance analysis. Laboratory parameters, such as haemoglobin, total lymphocyte count, serum albumin, transferrin, and CRP, were recorded. Participants were classified into two groups: the disease-related malnutrition (DRM) group and the no-DRM group. Using multivariate regression analysis, predictive factors for nutritional status were tested. Results: Among 340 participants, 63.2% were over 85 years old, 28.2% were men, and the median length of stay was 24 months (range: 6–119). Nutritional risk or malnutrition, as assessed by the MNA, was present in 60.8% of the residents. DRM was diagnosed in 39.4%, and frailty risk was diagnosed in 57.6%. Older adults with DRM had significantly lower MAMC, calfcircumference, MM, and serum albumin, as well as higher CRP concentrations compared with their No-DRM counterparts (all, at least, p < 0.05). The frailty risk (OR = 3.317), MM (OR = 0.732), PhA (OR = 0.033), serum albumin (OR = 0.070), and EuroQol visual analogue scale (OR = 0.961) were risk predictors of DRM in nursing home residents. Conclusions: This study supports the importance of conducting comprehensive nutritional assessments to ensure the earliest recognition of nutrition disorders in nursing homes. Older adults with DRM had greater unintentional weight loss, inflammation, and a high risk of frailty, as well as reduced MM, compared to those without DRM. Subclinical low-grade systemic inflammation is a risk factor for DRE and functional decline in older adults living in nursing homes. The generalisation of the study results is limited to institutionalised older adults without cognitive impairment who are clinically stable and functionally independent. Full article