Search Results (15,117)

Ternary gypsum–cement–pozzolan (GCP) binders represent a promising low-carbon alternative to traditional Portland cement-based systems for additive 3D printing (3DP). This study presents a systematic three-stage experimental framework for the development of printable and durable GCP mixtures: (i) optimisation of gypsum–cement–metakaolin binder proportions based on a ternary diagram for 25 formulations, (ii) comparative evaluation of different pozzolanic additives and secondary gypsum sources alongside comprehensive durability testing, and (iii) adaptation of the optimised mixtures for 3DP, focusing on rheological properties. The optimal composition was determined with 55 wt% gypsum, 22.5 wt% Portland cement, and 22.5 wt% metakaolin, achieving a 28-day wet compressive strength of 36.2 MPa and a softening coefficient of 0.85. Successful integration of secondary gypsum sources was demonstrated. The GCP 3DP mixtures were developed with water/binder ratios of 0.38–0.45 and sand/binder ratios of 0.5–1.4, with an open time of 20–40 min. The mixtures exhibit pronounced thixotropic behaviour, characterised by increasing yield stress over time and relatively stable plastic viscosity. Printability tests confirmed the stable application of 29–39 layers before structural buckling. 3DP under laboratory conditions successfully demonstrated the feasibility of producing architectural and structural elements from sustainable GCP compositions. Full article

Background: The well-established biopharmaceutical advantages provided by nanosuspensions (NSs) make their conversion into solid oral dosage forms particularly appealing for improving both patients’ compliance and product stability. However, such a transformation continues to represent a significant challenge. Aim: This study explored manual wet granulation (WG) as a laboratory-scale strategy to transform an NS containing cinnarizine (CN) into granules, which were intended for direct administration or to be further processed. Methods: A range of polymers, characterized by different interaction mechanisms with aqueous fluids, were employed as carriers to incorporate the CN-containing NS during manual WG. The resulting granules were thoroughly characterized before tableting. Results: The NS-loaded products exhibited satisfactory physio-technological properties, effective nanocrystal redispersibility, high drug load efficiency, and expected in vitro performance. Moreover, they turned out to be suitable intermediates for mini-tablet production. Conclusions: Based on the data collected, WG turned out to be an effective lab-scale method for transforming an aqueous CN-containing NS into solid products (i.e., granules and mini-tablets), while preserving the starting properties of the drug nanocrystals. By adjusting formulation and process parameters, a variety of release kinetics were achieved, highlighting the value of the pursued approach, especially for early-stage screening of new drug candidates belonging to class II of the biopharmaceutical classification system. Full article

Mountain regions are highly climate-sensitive, yet long-term observational evidence of elevation and seasonal climate dynamics in Central Asia remains limited. This study examines spatiotemporal trends in temperature (Tmean, Tmax, Tmin, and diurnal temperature range [DTR]) and precipitation across Kazakhstan’s transmountain regions using 74 meteorological stations (1981–2023). Data were analyzed using the Mann–Kendall test and Sen’s slope estimator, stratified across six elevation zones from lowlands (<400 m) to high mountains (>1500 m). Results reveal a robust, spatially coherent warming signal across all zones. Annual Tmean increased at a median rate of ~0.30 °C decade⁻¹, peaking at 0.36 °C decade⁻¹ above 1500 m, corresponding to an absolute increase exceeding 1.5 °C. Warming exhibited strong seasonal and diurnal asymmetries. Spring warmed most rapidly, with Tmean increasing >0.60 °C decade⁻¹ (approaching 3 °C total). Winter warming was driven by Tmin increases (up to 0.44 °C decade⁻¹), causing widespread DTR contraction, whereas summer warming was driven by Tmax increases, expanding DTR at higher elevations. Tmin showed the strongest elevation amplification overall. In stark contrast, precipitation trends were weak, spatially heterogeneous, and largely non-significant. Annual changes ranged from −6.63 to +14.35 mm decade⁻¹, with seasonal tendencies indicating modest, non-significant winter/spring wetting and summer drying. Ultimately, the results demonstrate a profound decoupling between strong, elevation-dependent warming and weak precipitation changes. The acute amplification of temperature, particularly during spring and summer at high elevations, has severe implications for snowmelt timing, glacier mass balance, evapotranspiration demand, and long-term water security in Kazakhstan. Full article

Morocco is among the regions in the Mediterranean basin most exposed to the impacts of climate variability and change. This increasing exposure requires a detailed and rigorous analysis of regional atmospheric dynamics to better understand the mechanisms behind recent climate trends. This study aims to examine the variability of circulation weather types (CWTs) at a regional scale over the period 1980–2019, within a geographical area bounded by latitudes 20° to 40° N and longitudes 10° to 22.5° W. The analysis is based on data from the NCEP-DOE Reanalysis 2, including mean sea level pressure (MSLP) and geopotential height at 500 hPa (Z500), with a spatial resolution of 2.5° in both latitude and longitude. The adopted methodology identifies daily CWT using a principal component analysis (PCA) in S-mode with Varimax rotation (PCAV), followed by the evaluation of their monthly distributions and temporal trends. The analysis highlights a marked trend toward increased atmospheric configurations conducive to hot conditions during the dry season, associated with the intensification and northward shift in the Saharan thermal low. This dynamic is reinforced by the increased frequency of ridges or high geopotential heights at 500 hPa, which transport warm tropical air toward the region. Moreover, the study reveals a notable decrease in the frequency of upper-level troughs at 500 hPa during the wet season. These upper-level troughs play a crucial role in cyclogenesis and the delivery of precipitation. These findings indicate a shift toward a regional atmospheric dynamic unfavorable to Morocco’s hydric balance, characterized by more frequent and intense summer heat and worsening winter drought. Full article

The purpose of this work was to synthesize and study catalytic systems based on a carbon-containing support obtained from coke fines from the Shubarkol deposit as a waste product of the coal industry for the processing of phenolic compounds. Based on the obtained carbon sorbent, mono- and binary catalysts with active phases of transition metal oxides (Fe, Co, Ni) were synthesized by wet impregnation, followed by heat treatment at 500–700 °C, as well as the aluminum oxide compositions. The surface morphology and elemental composition of the samples were studied by scanning electron microscopy (SEM) with energy dispersion analysis and elemental mapping (EDS mapping), and the content of active phases was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The catalytic activity was studied in phenol hydrogenation reactions. The CoO/C catalyst demonstrated the greatest activity, providing a 62.36% benzene yield during phenol hydrogenation. The catalytic activity of the CoO/C catalyst has also been studied in the hydrogenation reactions of structurally and functionally more complex compounds, pyrocatechol and resorcinol. The yield of benzene was 63.16% in the hydrogenation of pyrocatechol and 48.64% in the hydrogenation of resorcinol. It was found that the CoO/C catalyst exhibits the highest efficiency at a temperature of 420 °C, a pressure of 6–6.5 MPa and a reaction duration of 120 min. The results obtained make it possible to evaluate the prospects of using a carbon sorbent obtained from coke fines from the Shubarkol deposit as a support for CoO as part of an active and stable catalytic system designed for deep processing of phenolic compounds. Full article

Coastal groundwater in monsoon-dominated regions faces compounding threats from seasonal hydrological extremes and seawater intrusion (SWI), yet the molecular-scale response of dissolved organic matter (DOM) remains poorly understood. We conducted a two-season investigation in Mannar District, Sri Lanka, integrating hydrochemistry, fluorescence spectroscopy, and Fourier-transform ion cyclotron resonance mass spectrometry to characterize DOM dynamics across shallow and deep groundwater. Dry-season chloride averaged 302 mg/L (shallow—5 to 12 m) and 505 mg/L (tube wells—20 to 30 m), then declined by 60–80% during monsoon recharge. Despite this freshening, DOM dynamics were decoupled from salinity: shallow wells showed dry-season DOC peaks (6.64 mg/L) driven by soil concentration, while tube wells exhibited wet-season enrichment (5.02 mg/L). Shallow aquifers maintained consistently high humification indices (around 0.70) and aromatic-rich DOM, indicating sustained buffering by soil-derived inputs. In contrast, wet-season recharge in tube wells appeared to stimulate microbial processing, as indicated by elevated protein-like fluorescence (C2: 26% to 36%) and a higher contribution of nitrogen-bearing formulas (CHONs: 31.4% to 37.1%). Tube wells also accumulated reduced, energy-rich DOM with correspondingly high molecular lability indices. Paradoxically, correlation networks suggested that these saturated aliphatic and halogenated structures persist due to kinetic protection under low oxygen, high-salinity conditions. These findings indicate that aquifer structure and redox conditions control DOM biogeochemistry in coastal groundwater systems. At the molecular level, DOM dynamics are influenced by aquifer depth and seasonal recharge, leading to a decoupling between salinity and organic matter transformation. Full article

Rainfed wheat (Triticum aestivum L.) production in semi-arid regions is strongly influenced by precipitation variability, soil water availability, and crop management practices. This study evaluated the effects of nutrient management under uniform weed control on soil water dynamics, weed density, and grain yield of winter wheat grown under rainfed no-till conditions in southern Kazakhstan. Field experiments were conducted during the 2018–2021 growing seasons on gray soils characterized by low organic matter and limited nitrogen and phosphorus availability. Eight fertilization treatments, including phosphorus and nitrogen combinations and a micronutrient treatment, were arranged in a randomized complete block design. Soil moisture reserves, weed density, and grain yield were analyzed in relation to precipitation variability. Productive soil moisture reserves in the 0–100 cm layer at tillering (BBCH 21–25) ranged from 155 to 178.8 mm and were closely associated with overwinter precipitation. Balanced nitrogen–phosphorus fertilization reduced weed density from 38 plants m⁻² in the control to 16 plants m⁻² under the P₄₅N₇₀ treatment. Yield stability varied across dry, normal, and wet years, reflecting the influence of precipitation conditions on crop performance. Overall, the results suggest balanced fertilization in no-till systems contributes to improved resource use and more stable wheat production under variable precipitation. Full article

In a high-mountain gorge region, landslide hazards pose a serious threat to the upper Minjiang River, located at the eastern edge of the Tibetan Plateau. To map susceptibility in the upper Minjiang River basin, this study used a Random Forest model in conjunction with slope unit subdivisions. First, a landslide inventory containing 3785 landslides was established using human–machine interactive interpretation techniques. After a multicollinearity analysis, 11 key conditioning factors were selected to construct a spatial database, including elevation, slope, aspect, curvature, topographic wetness index, stream power index, distance to fault, peak ground acceleration, distance to road, vegetation index, and rainfall. The r.slopeunits algorithm was implemented to partition the study area into discrete slope units. The ideal parameter combination for slope units was determined through integrating the normalized slope aspect standard deviation and Moran’s I using an equal-weight scheme. Ultimately, 30,513 slope units were delineated in the upper Minjiang River. The random forest model trained on these ideal slope units was validated using a 70/30 split of landslide and non-landslide samples. In receiver operating characteristic (ROC) curve analysis, the model demonstrated excellent performance, with an area under the curve (AUC) of 0.852. The results indicate that small-scale landslides dominate the inventory in terms of frequency. Despite accounting for only 30% of the study area, the Very High and High susceptibility zones exhibit considerable degree of spatial overlap with current landslide clusters. Furthermore, shapley additive explanations (SHAP) explanatory metrics indicate that the random forest model’s predictive behavior is primarily influenced by terrain elevation, precipitation patterns, and proximity to transportation networks. Full article

This in vitro study evaluated the effect of irrigation on different polishing protocols and their influence on the surface roughness, microhardness, and mass of resin composites. Three resin composites (Admira^® Fusion, Filtek Supreme™ XTE, and Ceram.X Spectra™ STHV) were polished using four systems (Sof-Lex™, DIATECH^® ShapeGuard, Astropol^®, and Enhance™/PoGo™) under wet and dry conditions. Eight test groups were established for each resin composite (n = 10 per group). Vickers microhardness, surface roughness (R_a), and specimen mass were measured before and after polishing with one of the four systems, applied either with or without irrigation. For Admira^® Fusion polished with Sof-Lex^™, R_a values were lower without irrigation (p = 0.048), whereas Filtek Supreme^™ XTE and Ceram.X Spectra^™ STHV polished with the Enhance^™/PoGo^™ system showed lower R_a values when irrigation was used (p = 0.010 and p = 0.004, respectively). Sof-Lex^™ and DIATECH^® ShapeGuard produced the highest microhardness values for both Admira^® Fusion and Filtek Supreme^™ XTE. Moreover, specimens of Admira^® Fusion and Ceram.X Spectra^™ STHV polished with DIATECH^® ShapeGuard exhibited higher microhardness under irrigation (p = 0.048 and p = 0.027, respectively). Overall, polishing resulted in measurable material removal, reflected by a reduction in specimen mass, and in an increase in microhardness. Wet polishing generally increased microhardness, although the effect varied depending on the polishing system and resin composite. Clinicians should therefore consider both the resin composite and the polishing system when deciding whether to use irrigation, as appropriate irrigation control may help optimize the surface smoothness and microhardness of resin composite restorations. Conference Presentation: Preliminary data from this study were previously presented as an oral communication at the 32nd Portuguese Dental Association Annual Meeting. This manuscript represents a substantially expanded and revised version, developed as a full research article. Full article

Dopamine (DA) is a crucial catecholamine neurotransmitter, and its abnormal levels are closely associated with neurological disorders such as Parkinson’s disease. Electrochemical sensing technology offers a rapid and cost-effective platform for DA detection; however, it often suffers from interference from coexisting biomolecules such as ascorbic acid (AA) and uric acid (UA). In this study, we report a novel electrochemical biosensor based on PdMo bimetallene, a nanomaterial synthesized via a facile wet-chemical approach, aiming to enhance the detection performance and selectivity for DA. PdMo bimetallene is a highly curved, atomically thin two-dimensional nanosheet featuring abundant strained sites and a high density of active centers, enabling the selective and sensitive detection of DA. The results demonstrate that the as-prepared PdMo bimetallene-modified glassy carbon electrode (GCE) exhibits excellent electrocatalytic activity toward the oxidation of DA. The sensor displays a good linear response over the concentration range from 10 nM to 200 µM, with an ultrahigh sensitivity of 80 µA·µM⁻¹ cm⁻² and a low detection limit of 0.14 µM (S/N = 3). Owing to the synergistic electronic effect between Pd and Mo, the high density of exposed active sites, and the unique strained lattice structure of the bimetallene, the sensor enables accurate determination of DA concentrations even in the presence of interfering species such as AA and UA. In summary, the successfully fabricated PdMo bimetallene-based sensor offers the advantages of low cost, facile synthesis, a wide linear range, and high sensitivity, positioning it as a promising candidate for neurotransmitter detection applications. Full article

Dust concentration control in coal-fired power plants is challenged by large time delays and various disturbances, particularly in dry electrostatic precipitator-wet flue gas desulfurization (DESP-WFGD) processes, where the inner-loop dynamics are slower than those of the outer loop, limiting the effectiveness of conventional cascade tuning methods. This paper proposes a compensation-based simultaneous tuning method for cascade proportional-integral-derivative (PID)-PID control systems. The cascade structure is transformed into an equivalent single-loop system, allowing the outer-loop controller to reshape the equivalent plant dynamics. An equivalent controller is then designed using the simple internal model control method, from which the inner-loop controller is derived. Controller parameters are iteratively refined based on maximum sensitivity, overshoot, and integral absolute error. A feedforward controller is further introduced to reject measurable outer-loop disturbances. Simulation results under nominal, uncertain, and noisy conditions show that the proposed method achieves zero overshoot, improved robustness, and smoother control action compared with conventional separate tuning and Lee’s simultaneous tuning method. The proposed approach provides an effective and practical solution for dust concentration control in DESP-WFGD processes, and is extendable to industrial cascade systems with similar dynamic characteristics. Full article

The characteristics of two-phase flow in heterogeneous shale porous structures are of critical importance for oil and gas extraction and for evaluating the efficiency of underground resource recovery and carbon sequestration. However, although non-isothermal two-phase flow has been investigated in previous studies, systematic research on non-isothermal CO₂–crude oil displacement in heterogeneous shale porous structures remains relatively scarce. In this study, a multi-phase simulator was employed to simulate non-isothermal CO₂–crude oil displacement in heterogeneous porous structures, and the effects of injection rate, injection temperature, and wettability on two-phase flow characteristics in heterogeneous porous media were systematically analyzed. The results indicate that changes in the viscosity ratio between the displacing and displaced phases—induced by heat transfer—may be a key factor governing immiscible two-phase interfacial dynamics and flow behavior in heterogeneous porous structures. Injection temperature exerts a significant influence on both the main flow channels and local flow pathways within the porous structure; increasing the injection temperature of the displacing phase can effectively enhance displacement efficiency, with the steady-state CO₂ saturation increasing from 43.15% to 50.62% as the injection temperature increased from 293.15 K to 363.15 K. In addition, increasing the injection rate improves CO₂ sweep efficiency, with the steady-state CO₂ saturation increasing from 45.35% to 55.98% as the injection rate increased from 50 to 250 μm/s; however, excessively high injection rates lead to non-piston-like displacement and premature fluid breakthrough, and the CO₂ saturation decreased to 49.81% at 350 μm/s. Under strongly water-wet conditions, the CO₂ saturation after displacement stabilization is higher. Full article

The corrosion behavior of high-entropy alloys under cyclic wet–dry conditions simulating the salt-lake atmosphere was investigated. The composition, morphology, and electrochemical properties of the corrosion products formed on the alloy surface after corrosion were systematically analyzed. The results show that in a chloride-containing environment with alternating temperature and humidity, the Cr-containing oxide passive film formed on the alloy surface effectively inhibits the corrosion process in the early stages. In addition, electrochemical results show that the charge transfer resistance in the MgCl₂ system reaches 4.96 × 10⁵ Ω·cm² at prolonged exposure, which is significantly higher than that in the NaCl system, indicating a lower corrosion rate. However, over time, the passive film undergoes localized rupture due to chloride ion attack and stress, leading to pitting corrosion and expansion toward the substrate. This study reveals the corrosion mechanism of high-entropy alloys in high-altitude salt-lake atmospheric environments and provides crucial insights for material design and performance optimization for their engineering applications in salt-lake scenarios. Full article

Despite its significant water-saving potential, the adoption of alternate wetting and drying (AWD) irrigation remains limited due to infrastructure constraints and intensive manual monitoring requirements. An automated precision irrigation system was developed and tested at the Bangladesh Rice Research Institute research farm in Gazipur, Bangladesh. The system combined ultrasonic water-level sensors, capacitive soil moisture sensors, an Arduino-based microcontroller, a GSM communication module, and solar-powered automatic control gates. Field performance was evaluated following a Randomized Complete Block Design (RCBD) under four irrigation treatments: IRRISAT, IRRI35, IRRI25, and continuous flooding (CF). The first three irrigation treatments were operated using scheduled daily decision windows, in which irrigation actions were automatically triggered based on predefined schedules and sensor threshold values. In IRRISAT, irrigation started when soil moisture dropped slightly below saturation and stopped at a ponding depth of 5 cm, while IRRI35 and IRRI25 were triggered at volumetric soil water contents of 35% and 25%, respectively, with the same upper cutoff of 5 cm ponding depth; CF served as the control. The IRRI35 treatment achieved a high grain yield (7.76 t ha⁻¹) while reducing water use by 28% and energy consumption by 37% compared to CF. Water use efficiency was considerably higher under IRRI35 (9.4 kg ha⁻¹ mm⁻¹) than under CF (6.7 kg ha⁻¹ mm⁻¹). The automated system proved to be reliable and precise in scheduled irrigation control, significantly reducing water use and labor requirements. The findings suggest that large-scale adoption of the system under real-world cultivation conditions could reduce irrigation energy needs and contribute to sustainable water governance in rice production. Full article

An experimental investigation was conducted to examine the resistance to sulfate attack and chloride ion diffusion of concrete incorporating multiple industrial wastes (MIWC), including limestone powder (LP), tailings sand, and silica fume (SF). The degradation mechanisms of the MIWC under coupled sulfate wet‒dry cycles and chloride ion penetration are systematically revealed. Nine concrete mixtures were designed with variable water-to-binder (w/b) ratios, LP contents, SF dosages, and tailings sand/machine-made sand ratios. The results indicate that reducing the w/b ratio significantly enhances resistance to sulfate attack and chloride penetration. A moderate LP dosage optimizes pore structure and improves long-term sulfate resistance, whereas SF effectively refines the pore matrix and reduces the chloride diffusion coefficient. The coupled action of chloride and sulfate accelerates early-stage pore filling by corrosion products but promotes later-stage cracking because of expansive erosion products. A modified sulfate damage model and a multifactor coupled chloride diffusion model are established, which consider damage evolution, chloride binding, and time-dependent diffusivity. The predicted service life of the MIWC under marine exposure is in reasonable agreement with the experimental trends. This work provides a theoretical basis for durable design and industrial waste utilization in marine concrete structures. Full article