Search Results (2,020)

Polyacrylamide (PAM), as a widely used effective soil conditioner, can decrease sandy soil infiltration, but its function may decline significantly in a short time. Previous study results showed that the annual degradation rate of PAM in soil is about 10%, and the migration ability of PAM in soil is fairly weak; thus we hypothesized that the functional group of PAM is prone to aging caused by physical and biological factors, which is different from degradation caused by the breaking of long main chains into short ones. The sandy loam soil was selected to conduct column infiltration experiments to (1) determine the effects of PAM application and drying and wetting intensity on infiltration and (2) identify the causes of the aging effect. Soil samples were treated with three doses of PAM (0, 1, and 2 g·kg⁻¹) and incubated in three soil water conditions (constant wetting, moderate and strong drying/wetting cycles). Under constant wetting condition, the stable infiltration rates of soils were decreased by PAM. However, after two strong drying and wetting cycles, the decrement of infiltration rates of PAM-treated soils was reversed. The results of FTIR suggested that drying and wetting cycles led to the hydrolysis of amide groups in PAM, resulting in the weakening of PAM’s function on soil infiltration characteristics. The leaching amounts of NH₄⁺-N generated by the amide group hydrolysis increased through the drying/wetting alternation and the application of PAM. Therefore, based on the findings of this column study using a specific sandy loam soil under controlled intense drying–wetting cycles, reapplication of polyacrylamide (PAM) after two cycles may facilitate the sustained lowering of infiltration. However, this recommendation should be confined to analogous experimental conditions and necessitates further validation under field scenarios or for alternative soil types. Full article

This study analyzes changes in temperature, precipitation, and drought conditions on three small islands in the southern Adriatic (Vis, Lastovo, and Mljet) over the period 1981–2024, to identify the spatial and seasonal heterogeneity of the climate signal and its relationship with drought occurrence. The analysis reveals a statistically significant and consistent increase in mean annual air temperature at all analyzed stations, with warming being strongly seasonally asymmetric and most pronounced during the summer months. In contrast, precipitation trends are weak, spatially heterogeneous, and statistically insignificant in most cases, with a locally pronounced increase in precipitation in the interior and more orographically complex areas of Mljet. Drought conditions were assessed using the Standardized Precipitation Index (SPI) and the New Drought Index (NDI). The annual SPI exhibits strong interannual variability without a clear long-term trend, and in some cases an apparent increase driven by episodic extremely wet years. In contrast, the NDI clearly detects a systematic increase in aridity, particularly during the warm part of the year, reflecting the combined effect of rising temperatures and unfavourable precipitation distribution. June emerges as a key transitional month with a regionally coherent and statistically significant drying signal, whereas October shows weak and inconsistent trends due to the dominance of episodic precipitation extremes. The results confirm that drought assessment on small Mediterranean islands based solely on precipitation may be misleading, and that integrated indices incorporating the energy aspect of climate provide a more realistic representation of changes in aridity. Full article

The organic complexation of Cu²⁺ in aquatic systems dominates its chemical speciation, affecting its reactivity and bioavailability. Using voltammetry, we investigated Cu²⁺ organic complexing capacity (CuCC) in atmospheric samples, including water-soluble aerosol fraction, rainwater (wet-only deposition), and bulk deposition (wet and dry deposition), collected in a coastal marine area (National Park Brijuni, Adriatic Sea). The focus was on minimizing analytical interferences from surface-active substances (SAS) that accounted for up to 56% of dissolved organic carbon. Method optimization was performed using model SAS (humic-like substances, fulvic acid, and pollen-derived organic material), resulting in an optimal desorption potential of −1.4 V and the addition of 1 mg/L Triton X-100. Under these conditions, CuCC parameters of average ligand concentration and conditional stability constant of (209.8 ± 6.7) nM and log K = (10.2 ± 0.6) in water-soluble aerosol fraction, (117.1 ± 5.0) nM and log K = (9.6 ± 0.2) in rainwater, and (142.9 ± 4.1) nM and log K = (10.2 ± 0.2) in bulk deposition were determined. Atmospheric inputs represented a source of weak Cu-binding ligands for marine areas. In conclusion, short-term monitoring provided insight into the variability of different atmospheric inputs and offered a methodological basis for future long-term, more comprehensive studies. Full article

Predictive Maintenance (PdM) approach in Combined Sewer Systems (CSS) is gaining momentum due to advances in sensor technology, affordability and availability of data, and the rise of machine learning and data analytics. This study aims to characterize the general behavior of CSS under Dry and Wet weather conditions. To achieve this, 10 min resolution precipitation and water level data were collected from nearby SIAS stations and AMAP radar water level sensors, installed at the outlet chamber of the CSS, respectively. Precipitation data was used to segment continuous time series data into Dry Weather Flow (DWF) and Wet Weather Flow (WWF). DWF analysis exhibited unique flow patterns that strongly correlated with water consumption behaviors of households. For wet weather, a comparison was made between key rainfall parameters (depth, intensity) and peak water level data, and nonlinear relationships were observed that highlight the complex rainfall–runoff process. These findings underscore the need for separate predictive models tailored to DWF and WWF characteristics. Integrating high-resolution sensor data with machine learning models such as Long Short-Term Memory (LSTM) networks and anomaly detection, Autoencoders can enhance PdM, improving CSS management and reducing risks of blockage events and infrastructure failures. Full article

In response to the issues of concentrated early-stage hydration heat and significant self-shrinkage in high-strength cementitious grouting materials at low water-to-binder ratios, improvements were achieved by co-blending granulated blast furnace slag (GGBS) with calcium sulphatoaluminate (UEA) and magnesium oxide (MEA) expansive agents. The workability, mechanical properties, volumetric stability and hydration heat characteristics of the composite system were systematically investigated, and the underlying mechanisms were elucidated through microscopic analysis methods such as XRD, TG and SEM. The results indicate that GGBS improved the fluidity of the pastes and promoted the development of later-stage strength. At the same time, GGBS delayed the peak of hydration heat release and reduced total heat release. In terms of volume deformation, UEA expanded rapidly and exhibited significant compensatory shrinkage in the early stages. MEA expanded slowly in the early stages and displayed more sustained expansion under wet-curing conditions, but experienced significant shrinkage rebound in the later stages under dry environments. Further research revealed that GGBS inhibited the expansion performance of both types of expansive agents. This is primarily attributed to the consumption of Ca(OH)₂ within the system, which reduced the alkalinity of the liquid phase. GGBS physically restricted the formation and development of expansion products by promoting the densification of the C–S–H gel. Full article

Environmental variability, such as fluctuations in rainfall, can strongly influence spider population dynamics and assemblage composition. The study examined whether rainfall in the preceding three months, i.e., wet or dry conditions, using three different methods in the same sites within a eucalyptus forest, influenced the overall species and abundance of spiders captured and thus how wet or dry conditions influenced the overall spider assemblage and community structure. In south-east Queensland, Australia, rainfall is highly variable throughout the year and does not conform to distinct wet or dry seasons; therefore, “wet” and “dry” classifications in this study refer specifically to preceding rainfall conditions rather than seasonal categories. Sampling was conducted during dry conditions (75 mL of rain in the three months preceding collection) and during wet conditions (300 mL of rain in the three months preceding collection) to assess overall differences in spider richness, diversity and assemblage composition between wet and dry conditions by combining data from the three sampling methods. Species richness was significantly higher in dry conditions compared to the wet conditions. Diversity indices indicated that the more common spider species remained consistent between wet and dry conditions. Ordination analyses revealed changes between wet and dry conditions, primarily driven by fluctuations with less common spider species, rather than community changes at the family level. For vibration-based collections of spiders, only 30.5% of species overlapped between wet and dry conditions, whereas family-level overlap was 75%, indicating rainfall-driven changes occurred primarily at the species level rather than at the family level. Spider abundance was consistently higher under dry conditions across all methods. In vibration-based collections, 90% of species was collected within 60 min. However, using this method, species appeared more slowly under wet conditions, suggesting that rainfall may influence spider responses to vibrational stimuli. Survey method strongly influenced species richness with night hand collection of spiders resulting in the greatest number of species observed. Spider species richness and diversity collected using the vibration-based method were similar in wet and dry conditions and between sites. This supports the reliability of this method for sampling spiders that respond to vibrations and should be used complementarily with other survey methods. Full article

Sweat is a valuable biofluid for non-invasive health monitoring, as it contains electrolytes, metabolites, and organic compounds that can correlate with blood levels, making it highly attractive for wearable sensing. Building on advances in low-cost, portable electrochemical sensors, sweat analysis enables tracking of hydration status, metabolic stress, and energy availability via key markers such as sodium, potassium, lactate, and glucose. In the sports context, such wearable platforms can support performance optimization and recovery by assessing fluid loss and electrolyte balance in real time. Here, a multiplexed wearable sweat patch is developed to simultaneously monitor temperature, pH, ammonium, sodium, and sweat rate. The integrated platform demonstrates sensitivities of 10.1 mV/ln[NH₄⁺], 9.1 mV/ln[K⁺], 1.11 mV/ln[Na⁺], 14 mV/pH, 0.19% °C⁻¹, and approximately −1.0 mA (mL/min)⁻¹ for sweat rate, with stable signals and linear calibration responses over relevant physiological ranges. The sensor is implemented on a lightweight, biocompatible laser-scribed graphene on a PDMS substrate suitable for prolonged skin contact and mechanical deformation. In addition, a custom PDMS adhesive patch with optimized suction-cup microstructures is engineered to improve skin adhesion under both dry and wet conditions. Finally, the design of the platform was inspired by an adaptive cycling marathon across Saudi Arabia, where an earlier prototype of a wearable patch was deployed for real-time monitoring during a 30-day campaign. Full article

Background/Objectives: Emerging evidence suggests that alterations in lipid metabolism may play a contributing role in the pathogenesis of age-related macular degeneration (AMD). Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, a novel class of lipid-lowering agents, offer anti-inflammatory and antioxidant benefits, which may provide protective effects against AMD. We aimed to evaluate the risk of developing AMD among patients with atherosclerotic cardiovascular disease (ASCVD) who were newly treated with PCSK9 inhibitors compared with those receiving statins. Methods: This retrospective cohort study utilized data from the Global Collaborative Network within the TriNetX Research Network. Patients with ASCVD who were newly initiated on PCSK9 inhibitors or statins were identified and matched for age, sex, race, laboratory data, comorbidities, and concomitant medications. The primary outcomes were the hazard ratios (HRs) for developing AMD, dry AMD, and wet AMD. Propensity score matching (PSM) was used to adjust for baseline demographics and comorbidities. Results: After PSM, 50,102 patients were included in each group (PCSK9 inhibitor users vs. statin users). Compared to statin users, PCSK9 inhibitor users had significantly lower risks of AMD (HR, 0.81; 95% confidence interval [CI], 0.72–0.92) and dry AMD (HR, 0.78; 95% CI, 0.65–0.94), but not wet AMD (HR, 0.90; 95% CI, 0.70–1.16). Stratified and subgroup analyses showed reduced AMD risk among patients aged ≥65 years, White patients, female patients, and evolocumab users. Conclusions: In patients with ASCVD, compared with use of statins, use of PCSK9 inhibitors is associated with reduced risks of AMD and dry AMD, suggesting a potential novel strategy for managing a condition with limited therapeutic options. Full article

Future aircraft propulsion concepts (e.g., water-enhanced engines and fuel cells) will depend on efficient water recovery to enhance cycle efficiency and environmental performance. Operating conditions commonly involve droplet (mist) transport in turbulent air and wall-bounded films formed by droplet–wall interactions. This work develops an Eulerian–Lagrangian model within the RANS/URANS framework that accounts for air–droplet–wall phenomena—interfacial shear, impingement, and film advection. A dynamic contact-angle model, implemented and calibrated from static contact angle measurements performed in this study, represents wall wetting at the liquid–solid interface. The model is validated against experiments using two design metrics: pressure loss across the unit and recovered water mass fraction. At a low Mach number ($Ma=0.1$), saturated and dry air produce nearly identical pressure losses in the circular test section, whereas the separation lip geometry exerts a strong influence via local acceleration and separation. The simulations reproduce measured pressure drops and water mass recovery with close agreement. Full article

Frost buildup on copper tube-fin heat exchangers reduces their performance in cold, humid conditions. Fin length plays a key role in balancing heat transfer and frost resistance. This study experimentally examines how fin length affects thermal and frosting behavior. Four heat exchangers with fin lengths of $15.1$$\mathrm{m}$$\mathrm{m}$, $18.53$$\mathrm{m}$$\mathrm{m}$, $20.3$$\mathrm{m}$$\mathrm{m}$, and $23.5$$\mathrm{m}$$\mathrm{m}$ were tested at 2${}^{\circ }\mathrm{C}$/ 1${}^{\circ }\mathrm{C}$ dry-bulb/wet-bulb air temperature and $-6$${}^{\circ }\mathrm{C}$ coolant temperature under constant static pressure. Results show that longer fins increase total heat transfer—peak capacity rose from 512$\mathrm{W}$ to 566$\mathrm{W}$—but reduce heat transfer per unit area by about 30%. Operating time before defrosting increased by 30.6%, from $45.7$$\min$ to $59.6$$\min$, due to lower frost density. Total frost mass grew, but unit-area frost decreased by 12.7%. During defrosting, longer fins achieved greater absolute airflow recovery (from 195 to 213 ${\mathrm{m}}^3/\mathrm{h}$), though defrosting efficiency per gram of frost declined. Short fins ( 15$\mathrm{m}$$\mathrm{m}$) suit space-limited systems needing high surface efficiency. Long fins ( 23$\mathrm{m}$$\mathrm{m}$) benefit large systems requiring long run times and strong post-defrost performance. Medium lengths ( 17$\mathrm{m}$$\mathrm{m}$ to 20$\mathrm{m}$$\mathrm{m}$) offer a practical balance for general use. These findings support better heat exchanger design in frost-prone applications. Full article

This study assessed the productive and structural traits of the forage canopy and the performance of heifers grazing Marandu grass pastures overseeded with winter forages during the dry–wet transition in a tropical region. A completely randomized split-plot design with three replicates was used to compare three systems: Marandu grass overseeded with Oats and Ryegrass; Marandu grass overseeded with Oats and Clovers; and Marandu grass in monoculture. Holstein × Gyr heifers, averaging nine months of age with an initial body weight of 225.42 ± 50.27 kg, were managed under irrigated rotational grazing, with two days of occupation and 28 days of rest. Measurements were taken over three grazing cycles. Total forage mass and Marandu grass mass increased in the final cycle, with no differences among systems. The proportion and mass of winter forages did not differ between treatments, although overseeded pastures maintained about one-third of their composition as winter species. Animal performance was similar across systems, with greater body weight observed at the end of the experimental period. In conclusion, overseeding winter forages in irrigated Marandu grass pastures does not increase forage production or animal performance but does promote botanical diversification, with Oats showing better adaptation under these conditions. Full article

Steel reinforcement corrosion induced by chloride ingress in coastal environments is the dominant factor leading to the durability degradation of concrete structures. In this study, Ordinary Portland Cement (OPC) concrete beams and Portland Pozzolana Cement (PPC) concrete beams were used as test specimens, subjected to sustained loads to induce cracks, and exposed to accelerated reinforcement corrosion through 10 wet–dry cycles using a 3% NaCl solution. Testing methods including half-cell potential, corrosion current, and acoustic emission signals were employed to quantify the likelihood and progression of reinforcement corrosion. The results show that the half-cell potential of the loaded PPC beams remained below −350 mV, with a corrosion current density exceeding 0.5 μA/cm², indicating a significantly higher corrosion risk than that of the OPC beams; under unloaded conditions, the half-cell potential of the PPC beams remained consistently above −200 mV, with a corrosion current density below 0.2 μA/cm², exhibiting superior corrosion resistance. The event counts in the acoustic emission tests additionally revealed the progression of chloride ions gradually penetrating and corroding the steel reinforcement. Although PPC beams exhibit lower early-stage crack resistance under loading conditions and are prone to forming more cracks, their advantage in resisting chloride ingress becomes significant after appropriate mitigation measures are implemented to reduce early crack formation, making them remain a preferred material for reinforced concrete members in coastal environments. Full article

Bone tissue has a remarkable regenerative capacity; however, advanced strategies are needed to support the repair process for critical-sized defects. While autografts and allografts remain the gold standard, their limitations have stimulated alternative approaches in bone tissue engineering, in search of scaffolds capable of mimicking native bone properties to promote effective regeneration. In this study, silk fibroin (SF)-based composite scaffolds incorporating β-tricalcium phosphate (β-TCP) and poly-ε-caprolactone (PCL) were synthesized using a simple and innovative cryogenic foaming method. The proposed fabrication technique overcomes many limitations of current synthesis methods, such as long processing times, the use of solvents, and reliance on complex, energy-intensive equipment. The composites were characterized using infrared spectroscopy to confirm the incorporation of all three components and their chemical bond arrangements. µ-CT, SEM, and ESEM analyses revealed that SF/β-TCP/PCL scaffolds exhibited great porosity and dynamic interaction with water while preserving pore morphology in wet environments. Swelling behavior, indirect cytotoxicity, and cell proliferation tests recognized the greater performance of SF/β-TCP/PCL scaffolds in promoting long-term cell proliferation, maintaining superior mechanical properties. These findings indicate that the proposed original, simple, and relatively low-cost manufacturing approach enabled the fabrication of scaffolds with excellent mechanical performances, controlled and stable porosity under both dry and physiological-like conditions, and high biocompatibility. The resulting constructs demonstrated promising results for cell proliferation and osteoconductive behavior, supporting their potential suitability as artificial bone substitutes. Full article

The performance of fluid solidified soil (FSS) depends on the curing agents as well as, to a great extent, the soil type. Currently, most studies focus on a single type of soil, which limits the applicability of research findings to practical engineering scenarios involving diverse soil conditions. To address this issue, this study selects two representative soil types—clay (CL) and silt (ML)—and employs alkali-activated red mud–slag as curing agent to prepare FSS. Laboratory experiments were conducted to evaluate the influence of soil type on the engineering properties and durability of the specimens. Specifically, the effects of soil type on flowability and unconfined compressive strength were comparatively analyzed. Durability was assessed through shrinkage, water stability and wet–dry cycle tests. Furthermore, X-ray diffraction, Thermogravimetric, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and Brunauer–Emmett–Teller were utilized to characterize the microstructure and hydration products of the samples. The results indicate that an increasing proportion of ML leads to a decrease in overall flowability but a significant enhancement in late-age unconfined compressive strength. Meanwhile, the drying shrinkage of ML is gradually reduced, and both water stability and resistance to wet–dry cycles are correspondingly improved. Microstructural analyses reveal that the primary hydration product across all samples is C-(A)-S-H gel. Samples with higher ML content exhibit a denser structure and an increased volume of hydration products, which is consistent with the observed macroscopic performance trends. Full article

This study proposes a comprehensive methodology for the design and performance assessment of infiltration ponds integrated within hybrid grey–green urban drainage systems. The scope of the ponds is twofold: (i) increase infiltration of rainwater, and hence groundwater recharge, and (ii) decrease pluvial discharge downstream. The framework is applied to the Rome Technopole district, which serves as a pilot case for testing and demonstrating the procedure. Through 30-year continuous simulations performed with the EPA Storm Water Management Model and forced with a 5 min historical rainfall, the approach enables a performance-based evaluation that captures the full hydrological variability and the hydraulic performances of urban drainage systems. The methodology relies on physically based models for both the grey stormwater drainage network and the infiltration ponds, combined with a long-term simulation and functional analysis under transient conditions. The approach explicitly represents the main hydrological processes, including runoff generation, flow routing, storage dynamics, infiltration, and soil moisture variability, enabling a quantitative evaluation of peak-flow attenuation, infiltration efficiency, groundwater recharge volumes, seasonal variability, and wet–dry cycle behaviour. The latter is used to assess the long-term evolution of pond performance and its implications for maintenance activities, including clogging development and removal. Scenario analyses explore the influence of pond geometry and storage volumes, highlighting the trade-offs between hydrological efficiency, evaporation losses, and drawdown times. Beyond the specific application to the Rome Technopole developed in this study, we propose a generalizable, practitioner-oriented design procedure suited to contexts where infiltration-based solutions are desirable but regulatory guidance is fragmented. The proposed design workflow identifies critical parameters for both the hydraulic design and the operational management of infiltration ponds, enabling a statistical evaluation of their performance. The analysis of peak-flow reduction, infiltrated volumes, and the timing and frequency of wet–dry cycles provides a robust technical basis for the proper sizing, integration, and long-term assessment of infiltration ponds within urban drainage planning. Full article