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Double-arch tunnels, as one of the popular forms of tunnels, might be exposed to boiling liquid expanding vapour explosions (BLEVEs) associated with transported liquified petroleum gas (LPG), which could cause damage to the tunnel and even catastrophic collapse of the tunnel in extreme cases. However, very limited study has investigated the performance of double-arch tunnels when exposed to internal BLEVEs and in most analyses of tunnel responses to accidental explosions. The TNT-equivalence method was used to approximate the explosion load, which may lead to inaccurate tunnel response predictions. This study numerically investigates the response of typical double-arch tunnels to an internal BLEVE resulting from the instantaneous rupture of a 20 m3 LPG tank. Effects of various factors, including in-situ stresses, BLEVE locations, and lining configurations on tunnel responses are examined. The results show that the double-arch tunnels at their early-operation ages are more vulnerable to severe damage when exposed to the BLEVE due to the low action of in-situ stress of rock mass on the response of early-age tunnels. It is also found that directing the LPG tank to different driving lanes inside tunnels can affect the BLEVE-induced tunnel response more significantly than varying the configurations of tunnel lining. Moreover, installing section-steel arches in the mid-wall can effectively improve the blast resistance of the double-arch tunnels against the internal BLEVE. In addition, the prediction models based on multi-variate nonlinear regressions and machine learning methods are developed to predict the BLEVE-induced damage levels of the double-arch tunnels without and with section-steel arches.

Iron tailing porous concrete (ITPC) is a new type of green-engineered composite that uses iron ore tailing (IOT) powder to partially replace cement in conventional foamed concrete. This study investigates the dynamic properties of ITPC with a range of IOT content (15 % to 35 %) under high-strain rate loads, as well as the hydration products and microstructures of ITPC. Additionally, foamed concrete specimens without IOT powder are prepared and tested as references. The X-ray diffraction (XRD) results indicate that the addition of IOT powder causes the presence of iron oxide (Fe2O3) and silicon dioxide (SiO2) in the ITPC, resulting in a decrease in calcium silicate hydrate (C-S-H) gel and ettringite (AFt). A split Hopkinson pressure bar (SHPB) facility is used to perform impact tests at expected strain rates from 120 to 250 s−1. The experimental results demonstrate that the properties of ITPC obtained in dynamic loading tests exhibit significant IOT content dependence and strain rate effects. Moreover, scanning electron microscopy (SEM) analysis reveals that excessive IOT content results in the formation of numerous micro-cracks and loose pore structures within the ITPC specimens. ITPC with IOT content ranging from 25 % to 30 % achieves the optimal performance with high impact resistance and effective utilization of iron tailing waste. Specifically, at the expected strain rates of 120, 200, and 250 s−1, increasing the IOT content from 15 % to 35 % resulted in reductions of compressive strength by 37.52 %, 51.34 %, and 51.22 %, respectively. The corresponding dynamic increase factors of ITPC achieved the maximum values of 1.25 (25 % IOT content), 2.16 (30 % IOT content) and 3.12 (30 % IOT content), respectively.

Liquid–liquid separation, commonly referred to as oiling-out, frequently can occurs during crystallization, especially the anti-solvent crystallization process of phosphoryl compounds, and poses potential hurdle for high-quality product. Efficiently regulating oiling-out during crystallization remains a significant challenge. Among various techniques, ultrasound emerges as a green and effective approach to enhance the crystallization process. However, there is a dearth of in-depth research exploring the microscopic mechanisms of this process. Therefore, our research focused on the fructose-1,6-diphosphate (FDP), a typical phosphoryl compound, to gain a deeper understanding of how ultrasound influences the oiling-out process. The focused beam reflectance measurement (FBRM) technology was used to investigate the oiling-out phenomenon of FDPNa3 across various solvent ratios. In addition, the influence of ultrasound on the induction time was studied and the nucleation energy barrier was calculated. Finally, to further unravel the microscopic mechanisms, we utilized molecular simulation techniques to analyze the impact of ultrasound power on the dissolution-precipitation process. Our observations revealed a consistent oiling-out process that attainted a stable state regardless of the solvent employed. Notably, the results of the oiling-out induction time experiments indicated that ultrasound significantly reduced helped lower the nucleation energy barrier of FDP3- ions, thereby dismantling FDP3-clusters in solution. Thus, in turn, shortened the reduced induction time and promoted crystallization. Furthermore, ultrasound reduced the interactions between FDP3-ions and water molecules as well as FDP3- ions themselves. As simulated field intensity increased, these interaction forces gradually diminished, the thickness of the hydration layer surrounding the FDP3- clusters facilitating the disruption of clusters, ultimately enhancing the crystallization process.

Iron tailing porous concrete (ITPC) is a new foamed concrete material that using iron ore tailing powder to partially replace the cement. Previous investigations on ITPC primarily focused on its mechanical properties under static loads or low strain rate conditions, leaving a significant gap in its impact resistance performance at high strain rates. This study employed the split Hopkinson pressure bar (SHPB) to test ITPC specimens under impact loading with strain rate around 120 s−1. Density, water-binder (W/B) ratio, iron tailing powder content, polypropylene fiber length and content were taken as key design variables to prepare the ITPC specimens with different mix ratios and study their effects on the dynamic material properties of ITPC. Specifically, the failure modes, stress-strain relations, elastic moduli, compressive strengths and energy dissipation densities of the ITPC specimens with various design variables were recorded and compared. The test results indicate that the material density, fiber length and content have strong influences on the impact failure modes of ITPC. The elastic modulus, compressive strength and energy dissipation density of ITPC exhibit exponential growth with the material density. These parameters, however, show an initial growth followed by a decrease with the rising W/B ratio, fiber length and fiber content, and they reach the peak values at around 0.70, 9 mm and 2.0%, respectively. Moreover, the iron tailing powder content of 25% is recommended for ITPC for maintaining good impact resistance.

Background: Launched in March 2019, the National Centralized Drug Procurement (NCDP) initiative aimed to optimize the drug utilization framework in public healthcare facilities. Following the integration of Non-Vitamin K Antagonist Oral Anticoagulants (NOACs) into the procurement catalog, healthcare establishments in Suining swiftly transitioned to the widespread adoption of NOACs, beginning 1 March 2020.Objective: This study aims to comprehensively assess the impact of the NCDP policy on the efficacy of anticoagulation therapy, patient medication adherence, and the incidence of hemorrhagic events in individuals with non-valvular atrial fibrillation (NVAF) residing in Suining. The analysis seeks to elucidate the broader impacts of the NCDP policy on this patient demographic.Methods: This study analyzed patient hospitalization records from the Department of Cardiology at Suining County People’s Hospital, spanning 1 January 2017, to 30 June 2022. The dataset included demographic details (age, sex), type of health insurance, year of admission, hospitalization expenses, and comprehensive information on anticoagulant therapy utilization. The CHA2DS2-VASc scoring system, an established risk assessment tool, was used to evaluate stroke risk in NVAF patients. Patients with a CHA2DS2-VASc score of 2 or higher were categorized as high-risk, while those with scores below 2 were considered medium or low-risk.Results: 1. Treatment Cost Analysis: The study included 3,986 patients diagnosed with NVAF. Following the implementation of the NCDP policy, a significant increase in the average treatment cost for hospitalized patients was observed, rising from 8,900.57 ± 9,023.02 CNY to 9,829.99 ± 10,886.87 CNY (p < 0.001). 2. Oral Anticoagulant Utilization: Overall, oral anticoagulant use increased from 40.02% to 61.33% post-NCDP (p < 0.001). Specifically, NOAC utilization among patients dramatically rose from 15.41% to 90.99% (p < 0.001). 3. Hemorrhagic Events: There was a significant decrease in hemorrhagic events following the NCDP policy, from 1.88% to 0.66% (p = 0.01). Hypertension [OR = 1.979, 95% CI (1.132, 3.462), p = 0.017], history of stroke [OR = 1.375, 95% CI (1.023, 1.847), p = 0.035], age ≥65 years [OR = 0.339, 95% CI (0.188, 0.612), p < 0.001], combination therapy of anticoagulants and antiplatelets [OR = 3.620, 95% CI (1.752, 7.480), p < 0.001], hepatic and renal insufficiency [OR = 4.294, 95% CI (2.28, 8.084), p < 0.001], and the NCDP policy [OR = 0.295, 95% CI (0.115, 0.753), p = 0.011] are significant risk factors for bleeding in patients with atrial fibrillation. 4. Re-hospitalization and Anticoagulant Use: Among the 219 patients requiring re-hospitalization, there was a notable increase in anticoagulant usage post-NCDP, from 36.07% to 59.82% (p < 0.001). NOACs, in particular, saw a substantial rise in usage among these patients, from 11.39% to 80.92% (p < 0.001). 5. Anticoagulant Type Change: The NCDP policy [OR = 28.223, 95% CI (13.148, 60.585), p < 0.001] and bleeding events [OR = 27.772, 95% CI (3.213, 240.026), p = 0.003] were significant factors influencing the alteration of anticoagulant medications in patients.Conclusion: The NCDP policy has markedly improved anticoagulation management in patients with AF. This policy has played a crucial role in enhancing medication adherence and significantly reducing the incidence of hemorrhagic events among these patients. Additionally, the NCDP policy has proven to be a key factor in guiding the selection and modification of anticoagulant therapies in the AF patient population.