Influence of Si addition on the corrosion behaviour of 9 wt% Cr ferritic/martensitic steels exposed to oxygen-controlled molten Pb-Bi eutectic at 550 and 600 °C

Three 9 wt% Cr ferrite/martensite steels (two alloyed with Si) have been exposed to oxygen-controlled LBE at 550 and 600 °C, respectively. The passivating oxide scale consists of a spinel layer plus internal oxidation zone (IOZ). By adding Si, the thickness of spinel layer is decreased while the IOZ is enhanced. Moreover, a Si-rich oxide layer is observed underneath the spinel layer on Si-containing samples after 2000 h exposure at 600 °C. Besides, the less visible cracks/exfoliations on Si-containing samples indicate the positive role of Si addition on scale adherence

Comparison of Benchtop Fourier-Transform (FT) and Portable Grating Scanning Spectrometers for Determination of Total Soluble Solid Contents in Single Grape Berry (Vitis vinifera L.) and Calibration Transfer

Near-infrared (NIR) spectroscopy was applied for the determination of total soluble solid contents (SSC) of single Ruby Seedless grape berries using both benchtop Fourier transform (VECTOR 22/N) and portable grating scanning (SupNIR-1500) spectrometers in this study. The results showed that the best SSC prediction was obtained by VECTOR 22/N in the range of 12,000 to 4000 cm−1 (833–2500 nm) for Ruby Seedless with determination coefficient of prediction (Rp2) of 0.918, root mean squares error of prediction (RMSEP) of 0.758% based on least squares support vector machine (LS-SVM). Calibration transfer was conducted on the same spectral range of two instruments (1000–1800 nm) based on the LS-SVM model. By conducting Kennard-Stone (KS) to divide sample sets, selecting the optimal number of standardization samples and applying Passing-Bablok regression to choose the optimal instrument as the master instrument, a modified calibration transfer method between two spectrometers was developed. When 45 samples were selected for the standardization set, the linear interpolation-piecewise direct standardization (linear interpolation-PDS) performed well for calibration transfer with Rp2 of 0.857 and RMSEP of 1.099% in the spectral region of 1000–1800 nm. And it was proved that re-calculating the standardization samples into master model could improve the performance of calibration transfer in this study. This work indicated that NIR could be used as a rapid and non-destructive method for SSC prediction, and provided a feasibility to solve the transfer difficulty between totally different NIR spectrometers

Risk factors for acute postoperative hypertension in non-cardiac major surgery: a case control study

Abstract Purpose Acute postoperative hypertension (APH) is a common complication during the anesthesia recovery period that can lead to adverse outcomes, including cardiovascular and cerebrovascular accidents. Identification of risk factors for APH will allow for preoperative optimization and appropriate perioperative management. This study aimed to identify risk factors for APH. Patients and methods In this retrospective single-center study, 1,178 cases were included. Data was entered by two investigators, and consistency analysis was performed by another. Patients were divided into APH and non-APH groups. A predictive model was built by multivariate stepwise logistic regression. The predictive ability of the logistic regression model was tested by drawing the receiver operating characteristic (ROC) curve and calculating the area under the curve (AUC). Hosmer and Lemeshow goodness-of-fit (GOF) test was performed to reflect the goodness of fit of the model. Calibration curve was created to represent the relationship between predicted risk and observed frequency. Sensitivity analysis was performed to evaluate the robustness of the results. Results Multivariate logistic regression analysis showed that age over 65 years (OR = 3.07, 95% CI: 2.14 ~ 4.42, P < 0.001), female patients (OR = 1.37, 95% CI: 1.02 ~ 1.84, P = 0.034), presence of intraoperative hypertension (OR = 2.15, 95% CI: 1.57 ~ 2.95, P < 0.001), and use of propofol in PACU (OR = 2.14, 95% CI: 1.49 ~ 3.06, P < 0.001) were risk factors for APH. Intraoperative use of dexmedetomidine (OR = 0.66, 95% CI: 0.49 ~ 0.89, P = 0.007) was a protective factor. Higher baseline SBP (OR = 0.90, 95% CI: 0.89 ~ 0.92, P < 0.001) also showed some correlation with APH. Conclusions The risk of acute postoperative hypertension increased with age over 65 years, female patients, intraoperative hypertension and restlessness during anesthesia recovery. Intraoperative use of dexmedetomidine was a protective factor for APH

Research Progress in the Industrial Crystallization of Citrate—A Review

The citrate industry has a wide range of applications in food, pharmaceutical, and other fields. As a common class of food additives and functional supplements with tremendous development potential and strong core competitiveness, particles with good powder characteristics and functionalization are becoming one of the primary directions in the evolution of citrate into the high-end market. This article reviews the primary citrate crystallization techniques and examines the fundamental citrate crystallization mechanisms by describing citrate nucleation and growth during the industrial crystallization process. A variety of citrate hydrates are also summarized. The primary control conditions of the three essential product indices of purity, particle size, and grain shape are established. The need to take into account the density, fluidity, caking resistance, dissolution rate, suspension, bioavailability, and other indices of products is highlighted, along with applications for products that meet the purity and particle size requirements. While summarizing industrial citrate crystallization equipment, this paper also discusses the beneficial effect of continuous crystallization in achieving industrialization. Finally, the future development of citrate crystals is anticipated, and it is suggested that the combination of basic research and application research should be strengthened to explore the new application field of citrate crystals, and the automation and intelligence of the crystal preparation process should be realized as far as possible

Co-Doped MoS₂ Nanosheets with the Dominant CoMoS Phase Coated on Carbon as an Excellent Electrocatalyst for Hydrogen Evolution

Highly active and low-cost catalysts for hydrogen evolution reaction (HER) are crucial for the development of efficient water splitting. Molybdenum disulfide (MoS₂) nanosheets possess unique physical and chemical properties, which make them promising candidates for HER. Herein, we reported a facile, effective, and scalable strategy by a deposition–precipitation method to fabricate metal-doped (Fe, Co, Ni) molybdenum sulfide with a few layers on carbon black as noble metal–free electrocatalysts for HER. The CoMoS phase after thermal annealing in Co-doped MoS₂ plays a crucial role for the enhanced HER. The optimized Co-doped MoS₂ catalyst shows superior HER performance with a high exchange current density of 0.03 mA·cm^–2, low onset potential of 90 mV, and small Tafel slope of 50 mV·dec^–1, which also exhibits excellent stability of 10000 cycles with negligible loss of the cathodic current. The superior HER activity originates from the synergistically structural and electronic modulations between MoS₂ and Co ions, abundant defects in the active edge sites, as well as the good balance between active sites and electronic conductivity. Thanks to their ease of synthesis, low cost, and high activity, the Co-doped MoS₂ catalysts appear to be promising HER catalysts for electrochemical water splitting

Reduced Graphene Oxide/O-MWCNT Hybrids Functionalized with p‑Phenylenediamine as High-Performance MoS₂ Electrocatalyst Support for Hydrogen Evolution Reaction

Efficient hydrogen evolution through water splitting at low overpotentials is crucial to develop renewable energy technology, which depends on the design of efficient and durable electrocatalysts composed of earth-abundant elements. Herein, a highly and stable electrocatalyst for hydrogen evolution reaction (HER) has been developed on the basis of MoS₂ on p-phenylenediamine (PPD)-functionalized reduced graphene oxide/O-containing carbon nanotubes (rGO/O-MWCNT) hybrids via facile and green hydrothermal process. Among the prepared catalysts, the optimized MoS₂/rGO/PPD/O-MWCNT with nanosized and highly dispersed MoS₂ sheets provides a large amount of available edge sites and the improved electron transfer in 3D conductive networks. It exhibits excellent HER activity with a low overpotential of 90 mV and large current density of 47.6 mA·cm^–2 at 200 mV, as well as excellent stability in an acidic medium. The Tafel slope of 48 mV·dec^–1 reveals the Volmer–Heyrovsky mechanism for HER. Thus, this work paves a potential pathway for designing efficient MoS₂-based electrocatalysts for HER by functionalized conductive substrates

Metallic Cobalt Encapsulated in Bamboo-Like and Nitrogen-Rich Carbonitride Nanotubes for Hydrogen Evolution Reaction

Despite being technically possible, the hydrogen production by means of electrocatalytic water splitting is still practically unreachable mainly because of the lack of inexpensive and high active catalysts. Herein, a novel and facile approach by melamine polymerization, exfoliation and Co²⁺-assisted thermal annealing is developed to fabricate Co nanoparticles embedded in bamboo-like and nitrogen-rich carbonitride nanotubes (Co@NCN). The electronic interaction between the embedded Co nanoparticles and N-rich carbonitride nanotubes could strongly promote the HER performance. The optimized Co@NCN-800 exhibits outstanding HER activity with an onset potential of −89 mV (vs RHE), a large exchange current density of 62.2 μA cm^–2, and small Tafel slope of 82 mV dec^–1, as well as excellent stability (5000 cycles) in acid media, demonstrating the potential for the replacement of Pt-based catalysts. Control experiments reveal that the superior performance should be ascribed to the synergistic effects between embedded Co nanoparticles and N-rich carbonitride nanotubes, which originate from the high pyridinic N content, fast charge transfer rate from Co particles to electrodes via electronic coupling, and porous and bamboo-like carbonitride nanotubes for more active sites in HER