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Background: The coronavirus disease-2019 (COVID-19) pandemic worldwide has caused a high burden of mental problems, which may be associated with subjective cognitive impairment in the general population. Objectives: This cross-sectional survey aimed to investigate the level and pattern of cognitive failure (CF) and its negative changes during the COVID-19 pandemic among the general population in China. Methods: The participants completed an online questionnaire between April 18 and May 4, 2020, and those aged between 18 and 70 were included in this study. CF was measured using the 14-item CF Questionnaire (CFQ-14). Factors associated with CF and negative changes in CF were evaluated using multiple linear and logistic regression models. A total of 30,879 eligible participants were recruited; most were female (59.10%) and aged 31–45 (61.51%). Results: The mean CFQ-14 score was 15.62 (standard deviation = 11.55), and 4,619 (14.96%) participants reported negative changes in CF during the pandemic. Multiple regression analyses showed that participants with female gender, history of physical and mental disease, the self-perceived influence of COVID-19, altered appetite and taste preference, worse interpersonal relationships, long sleep duration, poor sleep quality, depressive, anxiety and posttraumatic stress disorder symptoms had a higher level of CF and negative CF changes, while regular exercise was associated with a lower risk of both outcomes. Conclusions: This study indicates that CF symptoms should be monitored in the general population during pandemics. A healthy lifestyle and reduction in psychological stress could help promote normal cognitive function during pandemics. [ABSTRACT FROM AUTHOR]

A quarter scale water model experiment is employed to investigate the effect of single and double porous plug placement and blowing flow rates on the mixing time, slag eye area, and slag entrapment depth. As a result, when the blowing flow rate is greater than 180 L min–1, the blowing effect of double blowing plugs is better than that of single blowing plugs. The open eye area and slag entrapment depth in the double blow plug arrangement are smaller than that in the single blow plug arrangement. In general, the ladle refining effect is better when the blow plug is arranged at 0.4R position and the angle between the two blow plugs is 120°. The final recommended argon blowing process is 240–300 L min–1 for the heating and alloying process and 60–120 L min–1 for the soft blowing process, respectively. [ABSTRACT FROM AUTHOR]

Cord steel is used for making tire frames and wire saws for cutting silicon wafers. The diameter of mainstream cutting wire has been developed to be lower than 100 μm. The size and deformation ability of inclusions are very important to the wire breaking rate of cord steel during the drawing process. In order to improve the deformation ability of the inclusions in cord steel, alkali metal oxide was added into the molten steel to improve the inclusions in the steel so as to obtain good, plastic, low-melting-point inclusions. Mass fractions of 0.3%, 0.5% and 1.0% K2CO3, Na2CO3 and B2O3 were added into cord steel, which were melted in 10 furnaces (including 0% alkali metal oxides, mass fractions of 0.3%/0.5%/1.0% K2CO3, Na2CO3 and B2O3). The morphology and composition of inclusions were observed by SEM-EDS. Factsage phase diagram calculations and experimental results show that, with the increase in Na2CO3 content in cord steel, the aluminum content in the inclusions gradually decreased. When the mass fraction of Na2CO3 was 0.5% per ton, most of the inclusions in the steel fell in the low melting point region (less than 1300 °C). With the increase in K2CO3 content in cord steel, the silicon content in the inclusions decreased gradually. When the mass fraction of K2CO3 was 0.5% per ton, most of the inclusions in the steel fell in the low melting point region. The deformation ability of the inclusions added with 0.5% Na2CO3 in the steel during forging was better than that of the inclusions added with 0.5% K2CO3. After adding B2O3, the inclusions in the steel were SiO2-MnO-Al2O3 inclusions or inclusions with SiO2-MnO-Al2O3 as the core and BN wrapped around. Boron could not be dissolved into the inclusions for plastic modification. [ABSTRACT FROM AUTHOR]

To investigate the evolution law of inclusions in 42CrMo-S steel, this paper samples and analyzes the steel during its refining process as well as the head and tail billets. An oxygen and nitrogen analyzer, a scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectrometry (EDS), and an ASPEX automatic inclusion scanning electron microscope are employed to analyze the cleanliness level of the molten steel in the refining stage and the head and tail billets. The results demonstrate that the total oxygen content at the end of LF slagging is 10.2 ppm, indicating that the refining slag has an excellent deoxygenation effect. During the RH refining process, the total oxygen content of the molten steel diminishes to less than 10 ppm and reaches 6.3 ppm at end-RH. The nitrogen content in the molten steel gradually increases during the smelting process and attains 65 ppm at end-RH. Upon arrival at LF, pure Al2O3 plays the role of the primary inclusions in the molten steel. Afterwards, the pure Al2O3 inclusions transform into Mg-Al spinel-type inclusions, Al2O3-MgO-CaO inclusions, and Al2O3-CaO inclusions. The number of CaS-type inclusions in the steel reaches the maximum after feeding the S wire. In the RH refining stage, the percentage of inclusions with a size less than 5 μm is maintained above 90%. Finally, the cleanliness level of the head and tail billets (the start and end of a casting sequence) is analyzed, and it is recommended that the cut scrap length for the head billet is 0.3 m and the reasonable cutting scrap length for the tail billet is 1 m. [ABSTRACT FROM AUTHOR]

In this paper, the effects of mold alternate stirring and single-direction continuous stirring on the internal quality of the billet were compared. When the mold alternate electromagnetic stirring was adopted, with the increase of stirring current form 260A to 350A, the central shrinkage cavity of the billet was disappeared, and the proportion of central equiaxed crystal zone increased gradually from 18.67% to 25.00%. The number of spot segregation larger than 1.0 mm2 in the billet was reduced from 18 to 10, and the maximum positive segregation of carbon and manganese decreased from 1.059 and 1.020 to 1.029 and 1.012, and the maximum negative segregation increased from 0.959 and 0.989 to 0.972 and 0.991, which improved the uniformity of elements distribution of the round billet. Through the above analysis, it can be seen that the mold alternate stirring mode with suitable parameters can improve the internal quality of the billet. [ABSTRACT FROM AUTHOR]

Inclusions have an important effect on the fatigue performance of bearing steels. Therefore, the study of the evolution of inclusions in the whole process and the reasonable control of inclusions (quantity, type, size, etc.) in steel can improve the production stability and fatigue performance of bearing steel. In this study, with the help of thermodynamic calculations and experimental studies, the evolution of the whole-process refining slag, oxygen and nitrogen content, and inclusions in bearing steel produced in a plant is systematically investigated. Overall, the refining slag composition of the refining process fluctuates less, and the oxygen content during LF refining and RH refining has been trending down, with an oxygen content of 5.7 × 10‒6 in the bearing steel billets. Although the cleanliness level is good for bearing steels, there is still room for improvement in refining slag composition, refining time, protected casting, and cut waste length. [ABSTRACT FROM AUTHOR]

Ca-SiO2 compounds compromise one of the most common series of oxide particles in liquid steels, which could significantly affect the service performance of the steels as crack initiation sites. However, the structural, electronic, and mechanical properties of the compounds in Ca-SiO2 system are still not fully clarified due to the difficulties in the experiments. In this study, a thorough investigation of these properties of Ca-SiO2 compound particles in steels was conducted based on first-principles density functional theory. Corresponding phases were determined by thermodynamic calculation, including gamma dicalcium silicate (γ-C2S), alpha-prime (L) dicalcium silicate (α′L-C2S), alpha-prime (H) dicalcium silicate (α′L-C2S), alpha dicalcium silicate (α-C2S), rankinite (C3S2), hatrurite (C3S), wollastonite (CS), and pseudowollastonite (Ps-CS). The results showed that the calculated crystal structures of the eight phases agree well with the experimental results. All the eight phases are stable according to the calculated formation energies, and γ-C2S is the most stable. O atom contributes the most to the reactivity of these phases. The Young's modulus of the eight phases is in the range of 100.63–132.04 GPa. Poisson's ratio is in the range of 0.249–0.281. This study provided further understanding concerning the Ca-SiO2 compound particles in steels and fulfilled the corresponding property database, paving the way for inclusion engineering and design in terms of fracture-resistant steels. [ABSTRACT FROM AUTHOR]

The size and distribution of TiN particles have a great influence on the properties of industrial pure iron. It is necessary to understand TiN precipitation behavior in bloom. Herein, inclusions in industrial pure iron cast billets are observed. The temperatures and conditions for TiN precipitation are calculated using thermodynamics and kinetics. The results show a large number of TiN inclusions in the bloom, and the quantity density is the largest at the inner arc of the bloom. This is caused by the large cooling rate at the inner arc and the homogeneous nucleation of inclusions. According to the thermodynamic calculations, during the solidification of industrial pure iron, TiN begins to precipitate at a solidification fraction greater than 0.82. The amount of TiN precipitated during solidification is 93%, with TiN continuing to precipitate from the solid phase after the solidification is complete. The results of TiN particle growth kinetics reveal that MgO is the most effective in promoting TiN nucleation, followed by δ‐Fe, CaS, and MgAl2O4, the effectiveness of Al2O3 as a heterogeneous nucleation core is relatively poor. The radius of the TiN particles decreases with a decrease in the N and Ti content and an increase in the cooling rate. [ABSTRACT FROM AUTHOR]

Biochar is extensively utilized for the remediation of environments contaminated with heavy metals (HMs). However, its derived-dissolved organic matter (BDOM) can interact with iron oxides, which may adversely influence the retention of HMs. This study investigates the effect of BDOM derived from tobacco stalk (TS) and tobacco petiole (TP) biochar on the redistribution behavior of As(V) in acid mine drainage (AMD)–impacted environments, particularly concentrating on the interactions with Schwertmannite (Sch). Results showed that TP–BDOM, abundant in lignin–like compounds, led to a low–amplitude release of As(V) from Sch under acidic conditions, reaching a maximum value (19.84 μg L−1), significantly lower than the release caused by TS–BDOM (87.46 μg L−1). Subsequently, 88.2% of the released As(V) were re–adsorbed in the TS–BDOM system, while 47.5% were retained in the TP–BDOM system. XRD analysis, in conjunction with SEM and STEM characterizations, confirmed that there were no additional crystalline phases or alterations in the microscopic morphological features of the particles throughout the reaction process. In–situ ATR–FTIR, complemented by 2D–COS analysis, demonstrated that aromatic N–OH groups and carboxylic in BDOMs coordinated to As–Sch, enhancing sulfate and As(V) release. It was also noted that no As(III) was detected under the influences of TP– and TS–BDOM. XPS results indicated that As(V) remained the predominant redox species even in the presence of BDOMs. These findings enhance our insight into BDOM's role in As(V) fate and transport within AMD-contaminated environments. [Display omitted] • Tobacco petiole biochar-DOM rich in lignin-like substances induces slow As release. • Polymerization of lignin-like compounds retards BDOM-induced As-Sch dissolution. • Released As(V) can be reabsorbed on Sch via bridging ligand with Fe and BDOM. • Surface inner-sphere As(V) complexes largely improve the stability of Sch. • Biochar-DOM can driven the repartitioning of As(V) from its associated mineral. [ABSTRACT FROM AUTHOR]

Growing evidence suggests a link between couple relationships and sleep, yet findings are inconsistent. We conducted a systematic review and meta-analysis, searching four databases up to March 2023, and included 62 studies with 43,860 participants. Results indicated a moderate correlation between better couple relationship quality and better overall sleep quality (r = 0.34, 95%CI = 0.09–0.59), as well as longer sleep duration (r = 0.39, 95%CI = 0.04–0.65). Regarding specific couple relationship domains, greater partner responsiveness was linked to improved overall sleep quality (r = 0.19, 95%CI = 0.13–0.25), while partner support showed no significant association (r = 0.03, 95%CI = −0.02-0.09). Increased partner conflict was associated with poorer overall sleep quality (r = 0.17, 95%CI = 0.06–0.27). In the studies that could not be meta-analyzed, greater partner conflict significantly correlated with longer actigraphy-based sleep latency and more wake episodes, but not necessarily with shorter actigraphy-based sleep duration. Increased self-disclosure was related to better overall sleep quality, whereas higher perceived rejection was linked to worse overall sleep quality. Higher closeness was not consistently associated with better overall sleep quality. Our results suggest a significant link between better couple relationships and improved sleep. Improving couple relationships may enhance sleep. However, further long-term cohort studies outside the USA are needed to evaluate these associations, particularly regarding specific couple relationship domains and specific sleep indicators. [ABSTRACT FROM AUTHOR]