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Currently, the effects of cooling and heating rates on the sizes and morphologies of impurities and grains in the typical Bi-bearing 1215 MS steels in the manufacturing processes have never been studied, so this work aims to deduce their solidification and heating behaviors. The in-situ heating experiments were carried out using a high-temperature laser confocal microscope. Results show that bismuth could refine the dendrite arm spacing. Liquid Bi segregates at the solidification interface of grain boundary and inhibits the growth of grains. The surface tension of Bi-MnS is smaller than Bi-Fe. A big heating rate aggravated the thermal vibration of grains in local areas and resulted in large local temperature difference. Slow heating and heat preservation are helpful for sulfides to absorb heat and for achieving large grains. To sum up, this study broadens the recognition of free-cutting steels and further contributes to the development of new steel grade. [ABSTRACT FROM AUTHOR]

Taking sludge in northwest China’s expressway service area as the research object, four dominant strains, including Bordetella sp. M05, Ochrobactrum sp. M06, Bacillus subtilis M07 and Staphylococcus sciuri M09, were obtained through specific screening. These microbes were prepared into inoculants and effectively promoted sludge composting. The time for the fermentation temperature of the composting process to reach 50°C was 3 days earlier than that of the control group. The high temperature (>50°C) lasted for 12 days and the highest temperature reached 63.5°C. After composting, the product was dark in color, free from odor, and the contents of organic matter, nitrogen, phosphorus and potassium increased by 44.1%, 125.9%, 311.1% and 269.2%, respectively, which made the composted product meet standards of GB/T 23486–2009 Sludge for Landscaping.

Domino conjugate addition/inert-bond activation is a useful strategy for improving the efficiency of synthesis. We summarize reports on domino conjugate addition/inert-bond activation and its applications in the rhodium-catalyzed ring-expansion and ring-opening reactions of azetidines. 1 Introduction 2 Rhodium-Catalyzed Domino Conjugate Addition/β-C Cleavage/ Protonation 3 Rhodium-Catalyzed Domino Conjugate Addition/N-Directed α-C(sp3)–H Activation 4 Conclusion [ABSTRACT FROM AUTHOR]

Large amounts of carbon dioxide (CO2) are discharged into air by combustion of gasoline and energy is input in a passenger internal combustion engine vehicle (ICEV) system through lifecycle phases. Thus, this study aims to evaluate the lifecycle carbon emissions and primary energy input of passenger ICEVs. With the life cycle assessment method, the calculations of carbon emission intensity and energy input intensity of materials used in lifecycle phases were made. The results show that the total lifecycle gasoline consumption of a vehicle was estimated to be 33,000 kg and the lifecycle CO2 emissions reached 81,311 kg per vehicle. Lifecycle CO2 emissions in use period occupied 89.43%, mainly attributed to the combustion of petrol. The average lifecycle CO2 emission intensity of the materials used was 2.33 kg/kg. The lifecycle carbon footprint of the passenger ICEVs was 163 g/km. The total CO2 emissions of ICEVs in Beijing were largest of all cities due to the maximum owning amount. The ratio of total lifecycle CO2 emissions of ICEVs in 13 large cities studied in this work to those of nationwide ICEVs was 0.179. Thus, more new energy vehicles will be given the prioritized choice in the future. [ABSTRACT FROM AUTHOR]

To further study the distribution and concentration of Bi particles in various cooling zones in newly solidified Bi content 1215 MS steels and to explore the relationship between cooling rate (R) and dendrite arm spacing, the horizontal solidification experiments were carried out by altering the R. Thermodynamics show liquid Bi was immiscible in Fe, which precipitated in the grain boundary and tended to co-exist with sulfides. Under moving rate ν = 0.2 mm/s, the average sizes of Bi particles and Bi-MnS inclusions in the chilled boundary, columnar grain and quenching grain zones were 1.2 μm, 1.4 μm, and 1.5 μm, while under v = 0.4 mm/s, those were 1.3 μm, 1.6 μm, and 1.2 μm, respectively. The average dendrite arm spacing of the solidified steel decreased with increasing moving rate (v). At R = 0.367 and 0.690°C/s, the average equivalent diameter ( d ˉ e ) of the inclusions in the columnar grain zone was respectively 1.102 μm and 1.119 μm. Under v = 0.4 mm/s, the concentrations of Bi particles in 1200 ppm and 2800 ppm Bi solidified steels in the chilled boundary, solidification front and center of the quenching grain zone were 0.0267%, 0.0375%, 0.0443%, 0.0463%, 0.0659%, and 0.0832%, respectively. [ABSTRACT FROM AUTHOR]

To accurately study the distribution characteristics of impurities and microstructures in the 2800 ppm Bi content 1215 MS steel, the horizontal solidification experiments were carried out by altering horizontal cooling processes. Results show that under moving rates (υ) = 0.3 mm/s and 0.5 mm/s the equivalent diameters of the impurities in steels at the interface between the chilled grain zone and columnar grain zone were higher at 1.6 ~ 1.8 μm, 2 ~ 3 times larger than those in the chilled boundary. Most small-sized inclusions were gathered in circular or linear distribution with the sizes of <1.0 μm. The morphologies of MnS/Bi-MnS inclusions were in rod-like, long strip, spindle, ellipsoidal, and spherical shape. The high υ value was beneficial for increasing the equivalent diameters of the impurities in the chilled grain zone and resulted in the reduction in the inclusions sizes in the columnar grain zone but it seldomly affected their sizes in the equiaxed grain zone. The morphologies of the equiaxed grains were in directional stacking, cross, anisotropy and coniferous pine types. [ABSTRACT FROM AUTHOR]