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Shrinkage porosity is a typical internal defect in the continuous casting billet, which occurs frequently and is difficult to solve. To explore the influence factors of central shrinkage porosity, a novel unsteady thermomechanical coupling analysis algorithm is developed based on the billet solidification characteristics, and the central shrinkage behavior during the ending solidification process is simulated. Results show that when the casting speed increases from 1.6 to 2.8 m·min−1 and the center outward displacement is reduced from 9.20 × 10−2 mm to 5.8 × 10−2 mm, it means casting speed has a significant effect on the formation of shrinkage porosity, and for this caster, the higher casting speed is more suitable for the secondary cooling zone. Without the changes in the solidification structure, when the superheat degree of molten steel increases from 10 to 40°C, the center outward displacement value decreases from 7.12 × 10−2 mm to 6.91 × 10−2 mm. In that case, the superheat degree has no obvious effect on the center displacement value.

In this article, physical and numerical simulation of the flow field in flexible thin slab caster funnel mold at high casting speed is carried out with a five-hole submerged entry nozzle (FHSEN), and characteristics of the flow field on funnel mold liquid level under different casting speeds (4, 5, and 6 m·min−1) and different submerged depths (130, 160, and 190 mm) are studied by comparing with the new submerged entry nozzle (NSEN) designed. Physical simulation is based on the funnel mold prototype. Numerical simulation is carried out based on FLUENT software, and industrial experiments of two kinds of submerged entry nozzle are also carried out. The results show that in the case of both physical and numerical simulation, the maximum surface velocity of the FHSEN funnel mold is 0.58 m·s−1, and the funnel mold liquid level is prone to slag entrapment. The NSEN funnel mold’ maximum surface velocity is 0.37 m·s−1. Compared with the FHSEN, the NSEN funnel mold’ maximum surface velocity decreases by 0.21 m·s−1, and funnel mold surface velocity decreases significantly. Finally, the accuracy of simulation results is verified by industrial tests, and it is also show that NSEN can greatly reduce funnel mold surface velocity and probability of slag entrapment.

Soft-contact of molten steel can be achieved by applying a high-frequency electromagnetic field above the mold of continuous casting, which can effectively eliminate surface defects and achieve billets with no cracks and no oscillation marks. It also has some influence on the mold flux. In this study, the effect of a high-frequency electromagnetic field (20 kHz) on a mold flux flow field was simulated using a finite element software, and the slag film was extracted using a slag film simulator. The effect of the high-frequency magnetic field on the microstructure of the mold flux was analyzed using X-ray diffraction, Raman spectroscopy, and mineral phase testing. The results show that the high-frequency electromagnetic field disrupts the orderly movement and increases the movement rate of the liquid flux. The precipitate phase of the slag film did not change, but the silicate dimer Q 1 decreased, the chain Q 2 increased, and the network degree was increased. The slag film structure changed from the original two-layer form of crystalline layer–glass layer into a three-layer form of crystal layer–glass layer–crystal, and the crystallization ratio increased by 35% on average. The grain-size melilite granularity was reduced from the original 0.12 to 0.005 mm.

A beam blank is ideal for H-beam production, but there are more defects in/on beam blanks than other common blanks. The study of the H-beam blank quality assurance system has great significance for production to determine the key factors causing defects and optimise the casting process parameters. Experimental analysis and numerical simulation, based on an actual production process, were used as research methods. The former was used to test and analyse the cracks, inclusions, and the flux in the mould to determine the preliminary factors causing defects in a beam blank. The latter was used to simulate the flow and temperature fields and the movement of inclusions to determine the key factor leading to defects and to optimize the casting process parameters. Online implementation of the recommendations of this project was developed, which proved that it is very useful and efficient to control surface cracks on the web and enhance cleanliness of an H-beam blank.

Precise control of inclusion and molten steel compositions during ladle-furnace refining is important to obtain high-quality steel. Mass-transfer behavior affects these compositions. A model was developed to investigate the mass transfer occurring between molten steel, slag, inclusions, and the refractory during ladle-furnace refining, using two-film theory to describe the reactions. A coupled-reaction model based on the CaO–Al2O3–MgO–SiO2–FeO–P2O5 slag and Mn–Si–Al–Ca–Mg–P–S–O steel systems was applied to describe the reactions between molten steel and slag; the reactions between the refractory lining and slag or steel were described using average industrial erosion rate data. The model was used to calculate changes in the compositions of molten steel and slag, oxygen activity at the slag–molten steel interface, and composition of the inclusions. The calculated results agreed with operational results for a 100 t ladle furnace at the Tangsteel plant in China.

Longitudinal crack defects are a frequent occurrence on the surface of thin slabs during the high-speed continuous casting process. Therefore, this study undertakes a detailed analysis of the solidification characteristics of hyper-peritectic steel thin slabs. By establishing a three-dimensional heat transfer numerical model of the thin slab, the formation mechanism of longitudinal cracks caused by uneven growth of the initial shell is determined. Based on the mechanism of longitudinal crack formation, by adjusting the performance parameters of the mold flux, the contradiction between the heat transfer control and lubrication improvement of the mold flux is fully coordinated, further reducing the incidence of longitudinal cracks on the surface of the casting thin slab. The results show that, using the optimized mold flux, the basicity increases from 1.60 to 1.68, the F- mass fraction increases from 10.67% to 11.22%, the Na2O mass fraction increases from 4.35% to 5.28%, the Li2O mass fraction increases from 0.68% to 0.75%, and the carbon mass fraction reduces from 10.86% to 10.47%. The crystallization performance and rheological properties of the mold flux significantly improve, reducing the heat transfer performance while ensuring the lubrication ability of the molten slag. After optimizing the mold flux, a surface detection system was used to statistically analyze the longitudinal cracks on the surface of the casting thin slab. The proportion of longitudinal cracks (crack length/steel coil length, where each coil produced is about 32 m long) on the surface of the thin slab decreases from 0.056% to 0.031%, and the surface quality of the thin slab significantly improves. [ABSTRACT FROM AUTHOR]

To fabricate polycarbonate (PC) composites with high mechanical and optical properties, PC composite films reinforced by cellulose nanocrystals esterified using palmitoyl chloride (palmitoylated cellulose nanocrystal [PAL‐CNCs]) were fabricated by casting‐evaporation and characterized by several techniques. It was shown that the PAL‐CNCs with a substitution degree of 0.43 and the crystalline index of 53.3% were better dispersed in chloroform and tetrahydrofuran, and achieved a water contact angle of 81.0°. The crystallite size and crystalline index of the PC in the composite film significantly increased to more than 5.2 nm and 51.5%, respectively, after the incorporation of the PAL‐CNCs. The PC composite film had an increase of 91.4% in tensile strength, 84.1% in Young's modulus, and a decrease of 5% in impact strength. Meanwhile, its UV–Vis‐light transmittance was above 90%. Therefore, the palmitoylated ‐CNCs were a better candidate for engineering PC composites with high mechanical performance and transparency. [ABSTRACT FROM AUTHOR]

We undertook a new approach to investigate the aerosol indirect effect of the first kind on ice cloud formation by using available data products from the Moderate-Resolution Imaging Spectrometer (MODIS) and obtained physical understanding about the interaction between aerosols and ice clouds. Our analysis focused on the examination of the variability in the correlation between ice cloud parameters (optical depth, effective particle size, cloud water path, and cloud particle number concentration) and aerosol optical depth and number concentration that were inferred from available satellite cloud and aerosol data products. Correlation results for a number of selected scenes containing dust and ice clouds are presented, and dust aerosol indirect effects on ice clouds are directly demonstrated from satellite observations. OCIS codes: 010.1650, 010.1110.

This article presents an account of the dialogue on a women's hotline, how to address problems related to sexual life. Issues on woman's sexual assertion, premarital sex, trial marriages, and oral sex are discussed.

The cellulose nanocrystal (CNC) aerogel was functionalized using aminosilane via vapor‐phase reaction and then the modified CNC aerogel was characterized by several techniques such as Fourier transform infrared spectroscopy, FE‐SEM, and elemental analysis. Finally, the CO2 adsorption on the aminosilane‐grafted CNC aerogel was featured using a dual‐site Langmuir adsorption model. The result showed triethylamine significantly enhanced the amine loading, being 7.06 mmol g−1 at 120°C. The primary amine groups in the aminosilane survived the vapor‐phase reaction. The amine groups were homogeneously distributed inside the aerogel due to its porous structure. The dual‐site Langmuir model could well describe its CO2 sorption characteristics. The adsorption capacity was up to 2.57 mmolCO2 g−1 at 25°C and 101.33 kPa, of which the chemisorption entirely dominated, and it decreased only 3%–4% after six runs. Therefore, these features positively suggested the vapor‐phase reaction provided a new and feasible method to functionalize CNC aerogel for the capture of CO2. [ABSTRACT FROM AUTHOR]

Herein, the effects of BaO (i.e. 5, 10, 15 and 20 pct) on the viscosity and structures of a new fluorine-free CaO-Al2O3-TiO2-based mold flux with w(CaO pct)/w(Al2O3 pct) ratio of 1.0 are investigated using a rotary viscometer, molecular dynamics (MD) simulations, and Raman spectroscopy. The viscosity of the samples (the testing temperature is 1300 °C) decrease from 0.46 to 0.21 Pa·s as the BaO content increased from 5 to 20 pct, and the activation energy decreases from 150.7 to 119.7 kJ·mol−1, the break temperature (Tbr) decreases from 1475 K to 1429 K which are achieved as the initial testing temperature of 1300 °C decreased under the furnace cooling. With the addition of BaO, the MD simulation results suggest that the coordination numbers (CNs) of Al (Ti)-O are reduced, while Q3, Q4, and Q5 are depolymerized into Q0, Q1, and Q2. The Raman spectroscopy results illustrate that the bridge oxygens (BOs) originating from the Ti-O-Ti (Al) linkages and Q2 (Al-O−) are depolymerized into Q1 (Si-O−) and Q0 (Al-O−) as the BaO content is increased. The Raman spectroscopy results agree well with those of the MD simulation. Therefore, BaO can simplify the structure of melts and decrease the viscosity of such systems. This work not only presents a new fluorine-free CaO-Al2O3-TiO2-based mold flux, but also deepens the understandings of the role of BaO in this system. [ABSTRACT FROM AUTHOR]

The prevalence and clinical relevance of KIT mutations in childhood core-binding factor (CBF) acute myeloid leukemia (AML) have not been well characterized. In this study, a total of 212 children with de novo AML were enrolled from a Chinese population and 50 (23.5%) of the patients were deemed CBF-AML. KIT mutations were identified in 30% of the CBF-AML cohort. The KIT mutations were clustered in exon 17 and exon 8, and KIT mutations in exons 8 and 17 were correlated with a shorter overall survival (OS) (5-year OS: 30.0 ± 14.5% vs. 73.0 ± 8.5%, p = .007) and event-free survival (EFS) (5-year EFS: 30.0 ± 14.5% vs. 73.0 ± 8.5%, p = .003). Multivariate analysis revealed KIT mutations as an independent risk factor in CBF-AML. Our results suggest that KIT mutations are a molecular marker for an inferior prognosis in pediatric CBF-AML. [ABSTRACT FROM AUTHOR]