Search Results (664)

Steel is an important product in many engineering sectors; however, steelmaking remains one of the largest ${\mathrm{CO}}_2$ emitters. Therefore, new governmental policies drive the steelmaking industry toward a cleaner and more sustainable operation such as the gas-based direct reduction–electric arc furnace process. To become carbon neutral, utilizing more scrap is one of the feasible solutions to achieve this goal. Addressing knowledge gaps regarding scrap heterogeneity (size, shape, and composition) is essential to evaluate the effects of increased scrap ratios in basic oxygen furnace (BOF) operations. This review systematically examines heat and mass transfer correlations relevant to scrap melting in BOF steelmaking, with a focus on low Prandtl number fluids (thick thermal boundary layer) and dense particulate systems. Notably, a majority of these correlations are designed for fluids with high Prandtl numbers. Even for the ones tailored for low Prandtl, they lack the introduction of the porosity effect which alters the melting behavior in such high temperature systems. The review is divided into two parts. First, it surveys heat transfer correlations for single elements (rods, spheres, and prisms) under natural and forced convection, emphasizing their role in predicting melting rates and estimating maximum shell size. Second, it introduces three numerical modeling approaches, highlighting that the computational fluid dynamics–discrete element method (CFD–DEM) offers flexibility in modeling diverse scrap geometries and contact interactions while being computationally less demanding than particle-resolved direct numerical simulation (PR-DNS). Nevertheless, the review identifies a critical gap: no current CFD–DEM framework simultaneously captures shell formation (particle growth) and non-isotropic scrap melting (particle shrinkage), underscoring the need for improved multiphase models to enhance BOF operation. Full article

Background: Depression, a major global health issue, is commonly treated with selective serotonin reuptake inhibitors (SSRIs). Given the link between depression and inflammation, nonsteroidal anti-inflammatory drugs (NSAIDs) may have adjunctive benefits. Clinically, SSRIs and NSAIDs are often co-prescribed for comorbid pain or inflammatory conditions. However, both drug classes pose risks of adverse effects, and their interaction may lead to clinically significant drug–drug interactions. Objectives: This study analyzed FDA Adverse Event Reporting System (FAERS) data (2004–2024) to assess gastrointestinal bleeding, thrombocytopenia, and acute kidney injury (AKI) potential risks linked to SSRIs (citalopram, escitalopram, fluoxetine, paroxetine, fluvoxamine, and sertraline) and NSAIDs (propionic/acetic/enolic acid derivatives, COX-2 inhibitors) in depression patients, alone and combined. Methods: Disproportionality analysis (crude reporting odds ratios, cROR) identified possible associations; drug interactions were evaluated using Ω shrinkage, additive, multiplicative, and combination risk ratio (CRR) models. Results: Gastrointestinal bleeding risk was potentially elevated with citalopram (cROR = 2.81), escitalopram (2.27), paroxetine (2.17), fluvoxamine (3.58), sertraline (1.69), and propionic acid NSAIDs (3.17). Thrombocytopenia showed a potential correlation with fluoxetine (2.11) and paroxetine (2.68). AKI risk may be increased with citalopram (1.39), escitalopram (1.36), fluvoxamine (3.24), and COX-2 inhibitors (2.24). DDI signal analysis suggested that citalopram in combination with propionic acid derivatives (additive model = 0.01, multiplicative model = 1.14, and CRR = 3.13) might increase the risk of bleeding. Paroxetine combined with NSAIDs (additive model = 0.014, multiplicative model = 2.65, and CRR = 2.99) could potentially increase the risk of thrombocytopenia. Sertraline combined with NSAIDs (Ω₀₂₅ = 0.94, multiplicative model = 2.14) might be associated with an increasing risk of AKI. Citalopram combined with propionic acid derivatives (Ω₀₂₅ = 1.08, multiplicative model = 2.17, and CRR = 2.42) could be associated with an increased risk of acute kidney injury. Conclusions: Certain combinations of SSRIs and NSAIDs might further elevate these risks of gastrointestinal bleeding, thrombocytopenia, and acute kidney injury in patients with depression. Given the potential drug–drug interactions, heightened clinical vigilance is advised when prescribing SSRIs and NSAIDs in combination to patients with depression. Full article

This study presents a detailed and comprehensive investigation into the macro-scale performance, strength gain mechanisms, environment and economic performance of graphene oxide (GO)-enhanced low-emission concrete. A comprehensive experimental program evaluated fresh and hardened properties, including slump retention, bleeding, air content, compressive, flexural, and tensile strength, drying shrinkage, and elastic modulus. Scanning Electron Microscopy (SEM), energy-dispersive spectroscopy (EDS), Thermogravimetric analysis (TGA) and proton nuclear magnetic resonance (¹H-NMR) was employed to examine microstructural evolution and early age water retention, confirming GO’s role in accelerating cement hydration and promoting C-S-H formation. Optimal performance was achieved at 0.05% GO (by binder weight), resulting in a 25% increase in 28-day compressive strength without compromising workability. This outcome is attributed to a tailored, non-invasive mixing strategy, wherein GO was pre-dispersed during synthesis and subsequently blended without the use of invasive mixing methods such as high shear mixing or ultrasonication. Fourier-transform infrared (FTIR) spectroscopy further validated the chemical compatibility of GO and PCE and confirmed the compatibility and efficiency of the admixture. Sustainability metrics, including embodied carbon and strength-normalized cost indices (USD/MPa), indicated that, although GO increased material cost, the overall cost-performance ratio remained competitive at breakeven GO prices. Enhanced efficiency also led to lower net embodied CO₂ emissions. By integrating mechanical, microstructural, and environmental analyses, this study demonstrates GO’s multifunctional benefits and provides a robust basis for its industrial implementation in sustainable infrastructure. Full article

This study employs advanced numerical simulation to investigate the influence of shelf temperature on the freeze-drying kinetics and product quality of Cordyceps militaris. Emphasis is placed on the glass transition and structural collapse mechanisms during the primary drying stage. A detailed computational model was developed to predict temperature profiles, glass transition temperature, collapse temperature, and moisture distribution under varying process conditions. Simulation results indicate that maintaining the shelf temperature below 10 °C minimizes the risk of structural collapse and volume shrinkage while improving drying efficiency and product stability. Based on the model, an optimal freeze-drying protocol is proposed: shelf heating at 0 °C, condenser plate at −32 °C, and chamber pressure at 35 Pa. Experimental validation confirmed the feasibility of this regime, yielding a shrinkage of 9.52%, a color difference (ΔE) of 4.86, water activity of 0.364 ± 0.018, and a rehydration ratio of 55.14 ± 0.789%. Key bioactive compounds, including adenosine and cordycepin, were well preserved. These findings underscore the critical role of simulation in process design and optimization, contributing to the development of efficient and high-quality freeze-dried functional food products. Full article

This study investigates the influence of SiO₂/Al₂O₃ molar ratios (2.25–3.00) and the replacement of red mud (RM) with GGBS (50–63%) on the performance of RM-based geopolymers to address the environmental issues posed by RM, including its high alkalinity and heavy metal content. The results indicated that increasing the SiO₂/Al₂O₃ ratio and incorporating GGBS reduced the fresh properties of the geopolymers. A higher SiO₂/Al₂O₃ ratio promoted the development of compressive strength, likely due to the elevated concentration of soluble silicates. The RM-based geopolymers with higher GGBS content also exhibited greater compressive strength. Moreover, the drying shrinkage and water permeability of RM-based geopolymers increased as the SiO₂/Al₂O₃ ratio and the GGBS content increased. The sustainability assessment revealed that CO₂ emissions were influenced by the SiO₂/Al₂O₃ ratio. In comparison to other RM-based geopolymers, the CO₂ emissions and costs in this study were reduced by 13.13–44.33% and 3.64–39.68%, respectively. This study discusses the effects of the SiO₂/Al₂O₃ molar ratios on the reaction process and strength formation mechanism of RM-based geopolymers, which provides an effective strategy for the resource utilization of RM. Full article

Full-section interval casting technology was adopted for the integral immersed tube of the Chebei Immersed Tunnel. Field tests (Chebei Immersed Tunnel) were conducted to establish the time-dependent development of the concrete shrinkage strain of the full-section casting segments. And laboratory experiments were then carried out to investigate the influence of factors such as the reinforcement ratio and stress, expansive agent content and composition, fly ash content, and curing temperature and humidity on the expansive effect of calcium–magnesium composite expansive agents. Field tests revealed that casting segments exhibit initial expansion followed by shrinkage, reaching a final strain of 348 με (microstrain). Laboratory investigations demonstrated that reinforcement (20–30 MPa stress) in post-casting belts effectively restrains segments without compromising the performance of calcium–magnesium composite expansive agents. The optimal 5:3:2 ratio of CaO, MgO 90s, and MgO 200s agents controlled shrinkage strain within 80 με by combining CaO’s rapid early expansion with MgO’s sustained effect. Field validation confirmed the mix’s effectiveness in preventing cracking, with key findings: (1) fly ash content and curing conditions significantly influence expansive behavior, and (2) shrinkage development can be precisely regulated through agent composition adjustments. Full article

In this paper, a new mechanical vibration technology applied to continuous casting production is studied, which is used to break the dendrite at the solidification front, expand the equiaxed dendrite zone, and improve the center quality of the billet. The exciting force of this vibration technology is provided by a new type of vibration equipment (Vibration roll) independently developed and designed. Firstly, an investigation is conducted into the impacts of vibration acceleration, vibration frequency, and the contact area between the Vibration roll (VR) and the billet surface on the internal stress distribution within the billet shell, respectively. Secondly, the billet with and without vibration treatment was sampled and analyzed through industrial tests. The results show that the area ratio of equiaxed dendrites in transverse specimens treated with vibration technology was 11.96%, compared to 6.55% in untreated specimens. Similarly, for longitudinal samples, the linear ratio of equiaxed dendrites was observed to be 34.56% in treated samples and 22.95% in untreated samples. Compared to the specimens without mechanical vibration, the billet treated with mechanical vibration exhibits an increase in the area ratio and linear ratio of equiaxed dendrite ratio by 5.41% and 11.61%, respectively. Moreover, the probability of bridging at the end of solidification of the billet treated by vibration technology was significantly reduced, and the central porosity and shrinkage cavities of the billet were significantly improved. This study provides the first definitive evidence that the novel mechanical vibration technology can enhance the quality of the billet during the continuous casting process. Full article

With the increasing demand for highway maintenance, enhancing the resource utilization of reclaimed asphalt pavement (RAP) has become an urgent and widely studied issue. Although foam asphalt cold recycling technology offers significant benefits in terms of resource utilization and energy saving, it still faces challenges, particularly the poor stability of foam asphalt mixtures. This study focuses on optimizing the performance of foam asphalt recycled mixtures through interface modification, aiming to promote the widespread application of foam asphalt cold recycling technology. Specifically, the research follows these steps: First, the optimal mix ratio of the recycled mixtures was determined based on the fundamental properties of foam asphalt and RAP. Then, zinc oxide, silane coupling agents, and amine anti-stripping agents were introduced to modify the recycled mixtures. At last, a series of tests were conducted to comprehensively evaluate improvements in road performance. The results indicate that the silane coupling agent enhances the low-temperature performance and fatigue. The fracture energy reached 526.71 J/m². Zinc oxide improves the low-temperature cracking resistance and dry shrinkage performance. Amine anti-stripping agents have minimal impact on the low-temperature performance. The linear shrinkage was reduced by 2.6%. The results of TOPSIS indicated that silane coupling agent modification exhibits superior fatigue resistance and low-temperature performance, achieving the highest comprehensive score of 0.666. Although amine-based anti-stripping agents improve fatigue life, they are not suitable for modifying foamed asphalt mixtures due to their detrimental effects on low-temperature performance and moisture resistance. Full article

Soil salinization severely limits global agricultural sustainability, particularly across the saline–alkaline landscapes of the Qinghai–Tibet Plateau. We examined how potassium fulvate (PF) modulates oat (Avena sativa L.) performance, soil chemistry, and rhizospheric microbiota in the saline–alkaline soils of the Qaidam Basin. PF markedly boosted shoot and root biomass, with the greatest response observed at 150 kg hm⁻². At the same time, it enhanced soil fertility by increasing organic matter, nitrate-N, ammonium-N, and available potassium, and improved ionic balance by lowering Na⁺ concentrations and the sodium adsorption ratio (SAR), while increasing Ca²⁺ levels and soil moisture content. Under the high-dose treatment (F2), endogenous fungal contributions declined sharply, exogenous replacements increased, and fungal α-diversity fell; multivariate ordinations confirmed that PF reshaped both bacterial and fungal communities, with fungi exhibiting the stronger response. We integrated three machine learning algorithms—least absolute shrinkage and selection operator (LASSO), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost)—to minimize the bias inherent in any single method. We identified microbial β-diversity, organic matter, and Na⁺ and Ca²⁺ concentrations as the most robust predictors of the Soil Salinization and Alkalization Index (SSAI). Structural equation modeling further showed that PF mitigates salinity chiefly by improving soil physicochemical properties (path coefficient = −0.77; p < 0.001), with microbial assemblages acting as key intermediaries. These findings provide compelling theoretical and empirical support for deploying PF to rehabilitate saline–alkaline soils in alpine environments and offer practical guidance for sustainable land management in the Qaidam Basin. Full article

The use of construction and demolition waste (CDW) as an alternative binder to ordinary Portland cement presents a promising solution through alkaline activation. This study evaluates the physical, mechanical, and microstructural behaviour of pastes and mortars produced with CDW—specifically concrete (RH) and ceramic (RC) waste—activated with NaOH and Na₂SiO₃ (SS) solutions. Mortars were prepared with NaOH/SS ratios of 0.2 and 0.3 and an activator-to-precursor (AA/P) ratio of 0.2. Results showed that higher NaOH content accelerated alkaline activation, reducing setting times from 6.2 h to 3.7 h for RC and from 4.6 h to 3.2 h for RH. Conversely, increasing Na₂SiO₃ content led to greater drying shrinkage, from −0.42% to −0.49% in RC and from −0.46% to −0.52% in RH. Compressive strength values at 28 days ranged from 7.6 to 8.2 MPa. X-ray diffraction (XRD) revealed the presence of non-reactive crystalline phases in both precursors, while Fourier transform infrared (FTIR) spectroscopy indicated the formation of CASH, CSH, and/or (N)CASH gels. This study highlights the potential of CDW as a sustainable alternative binder and the usefulness of the proposed method for optimising alkali-activated systems, contributing to circular economy strategies in the construction sector. Full article

The formation of soil cracks in soil slopes can compromise structural integrity. Guar gum, as a natural high-molecular-weight biopolymer, offers environmental and economic advantages in soil stabilizers due to its biodegradability, strong binding properties, and ability to form a three-dimensional network structure. To investigate its improvement effects, outdoor dry shrinkage cracking tests were conducted on silt loam using different guar gum dosages. Image preprocessing was performed using Photoshop software, and Python algorithms combined with the PCAS system were employed to quantitatively analyze the development process of cracks, revealing the evolution patterns of basic crack parameters, fractal dimensions, and probability entropy. The results indicate the following: (1) the addition of guar gum improves the water retention capacity of the soil, with the average moisture content of the samples decreasing as the guar gum content increases; (2) as the guar gum content increased, the total length, total area, and surface crack ratio of the cracks all increased, but the average crack width decreased significantly, with the maximum decrease reaching 9.8%, indicating that guar gum can effectively suppress the expansion of crack width and slow down the infiltration rate of rainwater; (3) the fractal dimension of crack area is less affected by guar gum content, while the fractal dimension of crack length is significantly influenced by guar gum content. Combining both parameters can effectively characterize crack morphology and distribution. The final fractal dimension of crack length generally ranges from 1.2 to 1.3, while the fractal dimension of the crack area remains stable between 1.55 and 1.65; (4) the addition of guar gum has a minor effect on the probability entropy of cracks, with a change of less than 3%, indicating that it does not significantly influence the randomness of cracks. Therefore, this study confirms that guar gum has a significant effect in controlling crack width and optimizing the uniformity of the crack network. Through its mechanisms of binding soil particles and delaying drying shrinkage, it provides an important reference for the ecological protection of cohesive soil slopes. Full article

Lithology identification during drilling plays a vital role in geological and geotechnical exploration, as it facilitates the early detection of formation-related hazards and supports the development of optimized mining strategies. Traditional lithology identification research involves problems such as fuzzy indicator characteristics and unbalanced sample quantities, which affect the accuracy and interpretability of model identification. In order to solve these problems, the Shanxi Guoqiang Coal Mine was taken as the research object, and a combined machine learning model was used to conduct a study on lithology identification during drilling. First, the least absolute shrinkage and selection operator (LASSO) algorithm was used to screen the independent variables and retain the parameters that contributed the most to lithology identification. Then, the synthetic minority oversampling technique (SMOTE) algorithm was used to expand the data samples, increase the amounts of minority sample data, and keep the ratios of various lithology data at 1:1. Then, the Bayesian optimization (BO) algorithm was used to optimize the penalty factor C and kernel function hyperparameter γ—two important parameters of the support vector machine (SVM) model—and the BO-SVM lithology identification model was established. Finally, the data samples were processed, and the results were compared with those of single models and unbalanced sample processing to evaluate their effect. The results showed the following: during the drilling process, the four indicators of drilling speed, mud pressure, slurry flow rate, and torque are strongly correlated with the lithology and can be used for lithology identification and classification research. After the data set was oversampled using the SMOTE algorithm, each model had better robustness and generalization ability; the classification result evaluation indicators were also greatly improved, especially for the random forest model, which had a poor original evaluation effect. The BO algorithm was used to optimize the parameters of the SVM model and establish a combined model that correctly identified 95 groups of data out of 96 groups of test samples with an identification accuracy rate of 99%, which was better than that of the traditional machine learning model. The evaluation results were compared with measured data, which confirmed the reliability of the combined model classification method and its potential to be extended to lithology identification and classification work. Full article

Background and Objectives: and Objectives: Admission hyperglycemia (AH) is common in acute ST-elevation myocardial infarction (STEMI) and linked to poor prognosis. The stress hyperglycemia ratio (SHR) reflects relative hyperglycemia and may more accurately predict outcomes. This study examined AH, SHR, and in-hospital stent thrombosis (ST) in STEMI patients undergoing primary percutaneous coronary intervention (p-PCI). Material and Methods: Retrospective analysis included 1034 patients. AH was defined as glucose ≥ 11.1 mmol/L at admission. SHR was calculated as admission glucose divided by estimated average glucose derived from hemoglobin A1c (HbA1c). The primary outcome was in-hospital stent thrombosis. Patients were grouped by the occurrence of in-hospital ST. Univariable, multivariable, and LASSO (Least Absolute Shrinkage and Selection Operator) logistic regression identified predictors of ST. Results: In-hospital ST occurred in 1.5% of patients. ST patients had higher Killip class, heart rate, white blood cell, platelet counts, creatinine, AH, and SHR. SHR was an independent predictor of ST (OR 3.15, 95% CI 1.88–5.27, p < 0.001), whereas AH was not (p = 0.182). Neutrophil count, correlated with WBC, was also a significant risk factor. ROC analysis showed SHR ≥ 1.26 as an optimal cutoff predicting ST. Conclusions: SHR is a strong independent predictor of in-hospital ST after STEMI, superior to AH. Monitoring and managing stress-induced hyperglycemia play a crucial role in the setting of STEMI. Further studies are needed. Full article

Recycled wood fiber (RWF) obtained through the multi-stage processing of waste wood serves as an eco-friendly green construction material, exhibiting lightweight, porous, and high toughness characteristics that demonstrate significant potential as a cementitious reinforcement, offering strategic advantages for environmental protection and resource recycling. In this study, high-performance sulfoaluminate cement (SAC)-RWF composites prepared by modifying RWFs with nano-silica (NS) and a silane coupling agent (KH560) were developed and their effects on mechanical properties, shrinkage behavior, hydration characteristics, and microstructure of SAC-RWF composites were systematically investigated. Optimal performance was achieved at water–cement ratio of 0.5 with 20% RWF content, where the KH560-modified samples showed superior improvement, with 8.5% and 14.3% increases in 28 d flexural and compressive strength, respectively, compared to the control groups, outperforming the NS-modified samples (3.6% and 8.6% enhancements). Both modifiers improved durability, reducing water absorption by 6.72% (NS) and 7.1% (KH560) while decreasing drying shrinkage by 4.3% and 27.2%, respectively. The modified SAC composites maintained favorable thermal properties, with NS reducing thermal conductivity by 6.8% through density optimization, whereas the KH560-treated specimens retained low conductivity despite slight density increases. Micro-structural tests revealed accelerated hydration without new hydration product formation, with both modifiers enhancing cementitious matrix hydration product generation by distinct mechanisms—with NS acting through physical pore-filling, while KH560 established Si-O-C chemical bonds at paste interfaces. Although both modifications improved mechanical properties and durability, the KH560-modified SAC composite group demonstrated superior overall performance than the NS-modified group, providing a technical pathway for developing sustainable, high-performance recycled wood fiber cement-based materials with balanced functional properties for low-carbon construction applications. Full article

As autogenous and thermal strains are significantly high in alkali-activated pastes, it becomes necessary to investigate ways to reduce these. This research studies how the volume changes of pastes made from slag activated by alkalis can be mitigated by substituting part of the slag with limestone filler and how this impacts the properties of the material, including autogenous strains, thermal strains, heat flow, compressive strength, and workability. The first part investigates how the different substitution rates impact the compressive strength and workability. The substitution rates of 15% and 30% emerged as the most optimal with a maximal reduction in the compressive strength of 23%. Five compositions were consequently investigated in the second part of the study. Isothermal calorimetry revealed that the limestone filler was probably not entirely inert and showed the effect of dilution, which is linked to the increase in the solution-to-binder ratio when the substitution rate increases. The autogenous shrinkage decreased when substituting 15% of the slag, while higher autogenous shrinkage was obtained when 30% was substituted. In addition, its rate of development was reduced. Finally, the coefficient of thermal expansion was generally slightly reduced and delayed when slag was substituted. Full article