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Owing to the non-uniform distribution of chemical composition and temperature during the heat treatment process, the residual stress and deformation of the workpiece emerge as crucial factors requiring consideration in managing the service performance and lifespan of shield machine cutter rings crafted from H13 steel. Considering H13 steel with titanium microalloying as the research object for the shield machine cutter ring, we simulate the quenching process using Deform-3D. The temperature field, phase transformation, stress evolution, and deformation amount after quenching are analyzed. The results demonstrate a strong agreement between the simulation and experimental results, offering valuable insights for optimizing the heat treatment process and enhancing the overall performance of shield machine cutter rings. [ABSTRACT FROM AUTHOR]

The study aims to analyze the effect of inert medium on coal combustion and effectively prevent spontaneous combustion of coal dust. Thermal analyzer and gas chromatograph were used to measure changes of quality and concentration of CO and CO2. The inert mediums are H2O, NH4H2PO4 and CaCO3. Tests of single inert medium, NH4H2PO4 and CaCO3 with different proportions and particle sizes on the inhibition of combustion were conducted. The results show that the inhibition effect of NH4H2PO4 and CaCO3 mixture is better than that of H2O and CaCO3 but weaker than NH4H2PO4 alone. The effect of inert medium in the process of instantaneous explosion and slow oxidation is not identical and there is no synergistic suppression effect on coal dust combustion. With the decrease of the size of NH4H2PO4 , the inhibition performance is enhanced.

A new organogelator based on Schiff base derivative has been designed and synthesized. It can be employed as building blocks to fabricate organic nano- or micro-structures. It shows excellent self-assembling properties. It could form stable gels with nanofiber structures in various organic solvents, such as n-butanol, benzyl alcohol, ethyl acetate, acetone, aniline. The gelation properties, structural characteristics and fluorescence of the gels were studied. Compared with the solution, the gel showed significantly enhanced emission. This organogel system can be used as a thermally driven fluorescence molecular switch. [ABSTRACT FROM AUTHOR]

The purpose of this research was to study how the bacteriaBacillus cereus(DCB1) utilizes calcium ions in a culture medium with carbon dioxide (CO2) to yield calcium carbonate (CaCO3). The bacteria strainDCB1was a dominant strain isolated from dolomitic surfaces in areas of Karst topographies. The experimental method was as follows: a modified beef extract-peptone medium (beef extract 3.0 g, peptone 10 g, NaCl 5.0 g, CaCl22.0 g, glass powder 2.0 g, distilled water 1 L, and a pH between 6.5 and 7.5) was inoculated withB. cereusto attempt to induce the synthesis of CaCO3. The sample was then processed by centrifugation every 24 h during the 7-day cultivation period. The pH, carbonic anhydrase (CA) activity, and the concentrations of both HCO-3and Ca2+in the supernatant fluid were measured. Subsequently, precipitation in the culture medium was analyzed to confirm, or otherwise, the presence and if present, the formation, of CaCO3. Methods used included X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive Spectroscopy (EDS). Meanwhile, the carbon source in the carbonate was classified by its isotope composition. Results showed thatB. cereuscan improve its pH value in this culture medium; concentrations of HCO-3and Ca2+showed a significant decline over the duration of the cultivation period. CA activity reached its maximum during the second day; XRD, SEM, TEM, and isotope analysis all revealed the presence of CaCO3as a precipitate. Additionally, these results did not occur in an aseptic control group: no detectable level of CaCO3was produced therein. In conclusion:B. cereuscan metabolize active materials, such as secretase, by its own growth and metabolism, and can either utilize atmospheric CO2, or respire, to induce CaCO3production. Experimental evidence is offered for a concomitant CO2reduction and CaCO3induction by microorganisms. [ABSTRACT FROM PUBLISHER]