Search Results (157)

Developing a more efficient, cleaner, and energy-saving pretreatment process is the primary goal for lignocellulosic biofuels production. This study demonstrated the feasibility of circulating high-concentration acetone–butanol–ethanol (ABE) obtained via in situ product recovery (ISPR) as a pretreatment liquor. Taking ABE solvent separated from pervaporation (PV) and gas stripping (GS) as examples, results indicated that under dilute alkaline (1% NaOH) catalysis, the highly recalcitrant lignocellulosic matrices can be efficiently depolymerized, thereby improving fermentable sugars recovery in saccharification stage and ABE yield in subsequent fermentation stage. Results also revealed delignification of 91.5% (stream from PV) and 94.3% (stream from GS), with total monosaccharides recovery rates of 56.5% and 57.1%, respectively, can be realized when using corn stover as feedstock. Coupled with ABE fermentation, mass balance indicated a maximal 106.6 g of ABE (65.8 g butanol) can be produced from 1 kg of dry corn stover by circulating the GS condensate in pretreatment (the optimized pretreatment conditions were 1% w/v alkali and 160 °C for 1 h). Additionally, technical lignin with low molecular weight and narrow distribution was isolated, which enabled further side-stream valorisation. Therefore, integrating ISPR product circulation with lignocellulosic biobutanol shows strong potential for application under the concept of biorefinery. Full article

In marine engineering applications, substituting conventional crushed stone coarse aggregates with coral aggregates offers dual advantages: reduced terrestrial quarrying operations and minimized construction material transportation costs. However, the inherent characteristics of coral aggregates—low bulk density, high porosity, and elevated water absorption capacity—adversely influence concrete workability and mechanical performance. To address these limitations, this investigation employed microbial-induced carbonate precipitation (MICP) for aggregate modification. The experimental design systematically evaluated the impacts of substrate concentration (1 mol/L) and mineralization period (14 days) on three critical parameters, mass gain percentage, water absorption reduction, and apparent density enhancement, across distinct particle size fractions (4.75–9.5 mm, 9.5–20 mm) and density classifications. Subsequent application trials assessed the performance of MICP-treated aggregates in marine concrete formulations. Results indicated that under a substrate concentration of 1 mol/L and mineralization period of 14 days, lightweight coral aggregates and coral aggregates within the 4.75–9.5 mm size fraction exhibited favorable modification effects. Specifically, their mass gain rates reached 11.75% and 11.22%, respectively, while their water absorption rates decreased by 32.22% and 34.75%, respectively. Apparent density increased from initial values of 1764 kg/m³ and 1930 kg/m³ to 2050 kg/m³ and 2207 kg/m³. Concrete mixtures incorporating modified aggregates exhibited enhanced workability and strength improvement at all curing ages. The 28-day compressive strengths reached 62.1 MPa (11.69% increment), 46.2 MPa (6.94% increment), and 60.1 MPa (14.91% increment) for the 4.75–9.5 mm, 9.5–20 mm, and continuous grading groups, respectively, compared to untreated counterparts. Full article

Massachusetts Bay in the northeastern United States is highly vulnerable to ocean acidification (OA) due to reduced buffering capacity from significant freshwater inputs. We hypothesize that acidification varies across temporal and spatial scales, with short-term variability driven by seasonal biological respiration, precipitation–evaporation balance, and river discharge, and long-term changes linked to global warming and river flux shifts. These patterns arise from complex nonlinear interactions between physical and biogeochemical processes. To investigate OA variability, we applied the Northeast Biogeochemistry and Ecosystem Model (NeBEM), a fully coupled three-dimensional physical–biogeochemical system, to Massachusetts Bay and Boston Harbor. Numerical simulation was performed for 2016. Assimilating satellite-derived sea surface temperature and sea surface height improved NeBEM’s ability to reproduce observed seasonal and spatial variability in stratification, mixing, and circulation. The model accurately simulated seasonal changes in nutrients, chlorophyll-a, dissolved oxygen, and pH. The model results suggest that nearshore areas were consistently more susceptible to OA, especially during winter and spring. Mechanistic analysis revealed contrasting processes between shallow inner and deeper outer bay waters. In the inner bay, partial pressure of pCO₂ (pCO₂) and aragonite saturation (Ω_a) were influenced by sea temperature, dissolved inorganic carbon (DIC), and total alkalinity (TA). TA variability was driven by nitrification and denitrification, while DIC was shaped by advection and net community production (NCP). In the outer bay, pCO₂ was controlled by temperature and DIC, and Ω_a was primarily determined by DIC variability. TA changes were linked to NCP and nitrification–denitrification, with DIC also influenced by air–sea gas exchange. Full article

The spontaneous combustion disaster of coal not only causes a waste of resources but also affects the safe production of coal mines. In order to accurately detect the range and location of the spontaneous combustion source of coal, this paper studies and summarizes previous research results, and based on the principles and research and development progress of existing detection technologies such as the surface temperature measurement method, ground temperature measurement method, wellbore temperature measurement method, and infrared remote sensing detection method, it briefly reviews the application of various detection technologies in engineering practice at this stage and briefly explains the advantages and disadvantages of each application. Research shows that the existing technologies are generally limited by the interference of complex environmental conditions (such as temperature measurement deviations caused by atmospheric turbulence and the influence of rock layer structure on ground temperature conduction) and the implementation difficulties of geophysical methods in mining applications (such as the interference of stray currents in the ground by electromagnetic methods and the fast attenuation speed of waves detected by geological radar methods), resulting in the insufficient accuracy of fire source location and difficulties in identifying concealed fire sources. In response to the above bottlenecks, the ”air–ground integrated” fire source location determination technology that breaks through environmental constraints and the location determination method of a CSC fire source based on a multi-physics coupling mechanism are proposed. By significantly weakening the deficiency in obtaining parameters through a single detection method, a new direction is provided for the detection of coal spontaneous combustion fire sources in the future. Full article

With the expansion of oil and gas exploration and development to complex oil and gas resource areas such as deep and ultra-deep formation onshore and offshore, the kick is one of the high drilling risks, and timely and accurate early kick detection is increasingly important. Based on the kick generation mechanism, kick characterization parameters are preliminarily selected. According to the characteristics of the data and previous research progress, Random Forest (RF), Support Vector Machine (SVM), Feedforward Neural Network (FNN), and Long Short-term Memory Neural Network (LSTM) are established using experimental data from Memorial University of Newfoundland. The test results show that the accuracy of the SVM-linear model was 0.968, and the missing alarm and the false alarm rate only was 0.06 and 0.11. Additionally, through the analysis of the kick response time, the lag time of the SVM-linear model was 1.3 s, and the comprehensive equivalent time was 23.13 s, which showed the best performance. The different effects of the model after data transformation are analyzed, the mechanism of the best effect of the SVM model is analyzed, and the changes in the effect of other models including RF are further revealed. The proposed early-warning model warns in advance in historical well logging data, which is expected to provide a fast, efficient, and accurate gas kick warning model for drilling sites. Full article

To solve the problems of carbon fiber (CF) electrodes, including poor frequency response and large potential drift, CFs were subjected to a roughening pretreatment process combining thermal oxidation and electrochemical anodic oxidation and then modified with Ag nanoparticles (AgNPs) using electroplating to prepare a CF electric field sensor. The surface morphology of the as-prepared AgNP-CF electric field sensor was characterized via optical microscopy, scanning electron microscopy, XPS, and energy-dispersive spectroscopy, and its impedance, polarization drift, self-noise, and temperature drift values were determined. Results show that the surface modification of the AgNP-CF electric field sensor is uniform, and its specific surface area is considerably increased. The electrode potential drift, characteristic impedance, self-noise, and temperature drift are 52.1 µV/24 h, 3.6 Ω, 2.993 nV/√Hz@1 Hz, and less than 70 µV/°C, respectively. Additionally, the AgNP-CF electric field sensor demonstrates low polarization and high stability. In field and simulated ocean tests, the AgNP-CF electrode exhibits excellent performance in the field and underwater environments, which renders it promising for the measurement of the ocean and geoelectric fields owing to its advantages, such as low noise and high stability. Full article

In the context of growing global energy demand and increasingly severe environmental pollution, ensuring the stable dispatch of new energy sources and the effective management of power resources has become particularly important. This study focuses on the reliability and stability issues of new energy dispatch considering the complementary advantages of multiple energy types. It aims to enhance dispatch stability and energy utilization through an innovative Distributed Overlapping Coalition Formation (DOCF) model. A distributed algorithm utilizing tabu search is proposed to solve the complex optimization problem in power resource allocation. The overlapping coalitions consider synergies between different types of resources and intelligently allocate based on the heterogeneous demands of power loads and the supply capabilities of power stations. Simulation results demonstrate that DOCF can significantly improve power grid resource utilization efficiency and dispatch stability. Particularly in handling intermittent power resources such as solar and wind energy, the proposed model effectively reduces peak shaving time and improves the overall network energy efficiency. Compared with the preference relationship based on selfish and Pareto sequence, the PGG-TS algorithm based on BMBT has an average utility of 10.2% and 25.3% in terms of load, respectively. The methodology and findings of this study have important theoretical and practical value for guiding actual energy management practices and promoting the wider utilization of renewable energy. Full article

To accelerate breeding progress for egg production traits in Lindian chickens, the genetic parameters for egg production and clutch-related traits in Lindian chickens were evaluated in the present study. Data regarding the age at first egg (AFE), egg number (EN), average clutch length (ACL), and average pause length (APL) were collected from two generations of Lindian chickens based on individual egg production records at 32 weeks of age (32–wk), 43–wk, and 52–wk. The results showed that the AFE of Lindian chickens was 179.3 d of age, with a heritability of 0.35. The heritability was 0.26 for EN32, 0.28 for EN43, and 0.34 for EN52. ACL showed moderate-to-high heritability (h² = 0.3–0.54), but APL traits showed low heritability (h² = 0.09–0.14). There were high positive genetic and phenotypic correlations for EN in the three periods from the start of laying up to 32–wk, 43–wk, and 52–wk. EN had high negative genetic correlations with AFE (r_G = −0.47–−0.80) and high positive genetic correlations with ACL (r_G = 0.45–0.81). The correlation between EN and APL was positive for 32–wk and 43–wk, but negative for 52–wk. These results indicated that the egg production of Lindian chickens could be improved by the selection of AFE, early EN, and ACL. Full article

Exploration in the Tarim Craton has established that small-displacement strike–slip faults control carbonate reservoirs’ development and oil and gas accumulation. Oil and gas primarily accumulate within a defined lateral distance from these faults. Material point method (MPM) simulations of such fault systems revealed a functional relationship between the regular spacing of initial oblique Riedel fractures and brittle layer thickness under simple shear. This thickness critically governs the spatial organization of the resultant fault system. Riedel shear zones propagate upwards from the base in a semi-elliptical pattern, producing fewer, but longer, shear zones with increasing brittle layer thickness. Stratum thickness exerts a first-order control on fault configuration during strike-slip deformation, modulating both fault segmentation patterns and interconnectivity. Key quantitative relationships emerged: (1) an inverse proportionality between stratum thickness and Riedel shear zone density and (2) a positive correlation between shear zone length and stratum thickness. This article provides experimental evidence and theoretical guidance for exploring deep-seated strike-slip faults in cratonic basins. Full article

To address the interception problem against maneuvering targets, this paper proposes a multi-agent cooperative guidance law based on a multi-directional interception formation. A three-dimensional agent–target engagement kinematics model is established, and a fixed-time observer is designed to estimate the target acceleration. By utilizing the agent-to-agent communication network, real-time exchange of motion state information among the agents is realized. Based on this, a control input along the line-of-sight (LOS) direction is designed to directly regulate the agent–target relative velocity, effectively driving the agent swarm to achieve time-to-go consensus within a fixed-time boundary. Furthermore, adaptive variable-power sliding mode control inputs are designed for both elevation and azimuth angles. By adjusting the power of the control inputs according to a preset sliding threshold, the proposed method achieves fast convergence in the early phase and smooth tracking in the latter phase under varying engagement conditions. This ensures that the elevation and azimuth angles of each agent–target pair converge to the desired values within a fixed-time boundary, forming a multi-directional interception formation and significantly improving the interception performance against maneuvering targets. Simulation results demonstrate that the proposed cooperative guidance law exhibits fast convergence, strong robustness, and high accuracy. Full article

To achieve interconnects of rectangular polymer dielectric waveguides (PDWs) at the W-band, this paper presents a novel low-loss and high-bandwidth horizontally polarized transition between a rectangular PDW and a microstrip line (ML), which can achieve a rectangular PDW array. The proposed structure consists of a patch, a bent ridge waveguide, a tapered ridge waveguide, a dielectric-filled waveguide, and a tapered horn. An equivalent circuit model is established for synthesis design, and the transition is manufactured utilizing printed circuit board (PCB) and computerized numerical control (CNC) technologies. A rectangular PDW interconnect with two designed transitions is constructed and experiments are conducted. The measured results indicate that the rectangular PDW interconnect with two transitions operates within a frequency range (|S₁₁| < −10 dB) of 81.9–108.2 GHz, and the insertion loss of the transition is 0.51–2.01 dB in this frequency range. Then, the designed transition is used to achieve a rectangular PDW array with two rectangular PDWs and two transitions, which has a far-end crosstalk (FEXT) of −55.4 to −21.7 dB in the frequency range of 78.1–110 GHz. Full article

This study explores the spatiotemporal dynamics of SOC and microbial-mediated mechanisms in the Yellow River Delta wetlands. Using redundancy analysis and microbial community profiling, we show that vegetation drives distinct SOC storage patterns: Phragmites australis ecosystems exhibit the highest SOC sequestration, followed by Suaeda salsa and Tamarix chinensis habitats, where salt-tolerant taxa like Desulfobacterota and Halobacteriaota promote short-term carbon storage via anaerobic metabolism. The microbial community structure is shaped by both vegetation-induced microhabitats and environmental gradients: SOC and total nitrogen dominate community assembly, while electrical conductivity, pH, and sulfur/nitrogen nutrients regulate spatiotemporal differentiation. Seasonal turnover drives the reorganization of microbial community structures, shaping the dynamic equilibrium of carbon pools. Seasonal DOC dynamics, linked to tidal fluctuations and exogenous carbon inputs, highlight hydrology’s role in modulating active carbon pools. These findings reveal tight linkages among vegetation, microbial functional guilds, and soil biogeochemistry, critical for wetland carbon sequestration. Full article

Different temperatures and continuous loads have significant effects on the long-term performance of asphalt concrete facings. The effects of temperature and stress on creep strain and creep rate were analyzed by designing a bending creep test of impermeable asphalt concrete under different temperatures and stresses. Based on the test data, a time–temperature–stress-dependent creep constitutive model was constructed to predict the long-term creep behavior of asphalt concrete at low temperature. The results showed that the creep behavior of asphalt concrete showed significant temperature and stress dependence. The creep behavior accelerated as the temperature or stress increased, especially under high-stress conditions, indicating obvious nonlinear characteristics. Under the condition of 0.2376 MPa, when the temperature increased from 0 °C to 20 °C, the strain at the creep time of 9330 s nearly increased by 24 times. Under 0 °C, the loading stress increased from 0.2376 MPa to 1.3176 MPa, and the strain nearly increased by six times at a creep time of 880 s. The creep strain is expected to increase to 8% after 8 years at −15 °C and 0.2376 MPa. The results can provide a scientific basis for engineering practice and significant implications for designing and maintaining asphalt concrete facings. Full article

Background: Recent setbacks in malaria control in Comoros demand a reassessment of its evolving epidemiology. Methods: Using the Global Burden of Disease (GBD) Study 2021 data, we analyzed malaria trends from 2010 to 2021, stratified by sex. We quantified the contributions of demographic and epidemiological factors to these trends and identified risk factors for malaria-related disability-adjusted life years (DALYs). Results: From 2010 to 2021, malaria cases, deaths, and DALYs in Comoros fell by −90.22%, −94.44%, and −94.88%; and the corresponding age-standardized rates declined with EAPCs of −18.70% (95% CI: −33.77 to −0.20), −23.89% (95% CI: −36.58 to −8.66), and −24.49% (95% CI: −36.88 to −9.66), with steeper declines in males. Nevertheless, all indicators increased in 2018 and again in 2021. In sub-Saharan Africa, only cases increased, while other metrics declined slightly. In Comoros, incidence shifted mainly to adults ≥25 years, unlike sub-Saharan Africa, where children < 5 years were most affected. Population growth drove increases in cases, deaths and DALYs, whereas epidemiological shifts had the opposite effect. Child underweight was the leading risk factor for malaria DALYs. Conclusions: Existing interventions can achieve malaria control in Comoros; however, rebounds in 2018 and 2021 highlight the need to identify and address drivers of resurgence. Full article

AgCl microcrystals are used in visible light photocatalysis. However, their properties depend strongly on the morphology of the crystals and the degree of exposure of the crystal planes. Despite extensive research conducted on the synthesis of AgCl microcrystals, the majority of existing studies have focused on the stable growth of crystals. The role of Cl⁻ ions concentration as a key factor controlling the microcrystals morphology has not been fully explored, which limits the precise tuning of the morphology of AgCl microcrystals. In this study, AgCl microcrystals with controllable morphology are successfully synthesized by a facile solvothermal method. During the preparation process, ethylene glycol (EG) is utilized as a solvent, while polyvinylpyrrolidone (PVP) is employed as a surfactant. We systematically investigate the etching mechanism of AgCl microcrystals by analyzing the effect of sodium chloride (NaCl) concentration on their morphology. This investigation involves the integration of diverse characterization methods, including scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and geometrical struc-ture analysis. The results demonstrate that Cl⁻ functions as both a surfactant, thereby promoting the nucleation of cubic microcrystals, and as an etchant, selectively etching the crystal surface. The order of selective etching on the crystal surface follows (100) planes > (110) planes > (111) planes. Based on this new mechanism, AgCl microcrystals with various morphologies, such as cube, octopod and dendrite, are successfully prepared, which provides a new idea for the precise design of noble metal halide microcrystals. Full article