Modal and strength analysis of coal mine mobile refuge chamber

Structural strength, stiffness, etc. are essential safety performances of mine refuge chamber. In this article, the safety performance of the chamber which is under the impact load was evaluated by the method of numerical analysis. First of all, according to some relative standards, a chamber model was established by applying numerical modeling software. In this way, a method of finite element analysis (FEA) was instituted and we used AUTODUN to simulate the process of transmission of blast waves in the underworkings. On the basis of Fourier transform theory, the spectrum analysis of the blast waves acting on the chamber has been done. In order to obtain the natural frequency, a model analysis of the chamber was made by applying OPTISTRUCT. Then the main frequency and the natural frequency were compared. The result shows that the resonance will not happen so that the safety performance of the chamber meets the demand of engineering safety. The structural strength of the chamber was analyzed by using LS-DYNA, and the result comes out that the pressure throughout the chamber will not cause damage to the chamber. After that, according to the simulation results, we proposed some pieces of advice which will be meaningful for the design and the improvement of the chamber

Promissing cerium-doped barium manganate perovskite for solar thermochemical hydrogen production

Over the past decade, nonstoichiometric oxides have been investigated for solar thermochemical water splitting applications because of their ability to partially reduce and create oxygen vacancies at high temperatures and subsequently reoxidize in steam at lower temperatures, uptaking the oxygen into the lattice and producing hydrogen as a consequence (c.f. Figure 1a). Cerium oxide is currently viewed as the leading candidate for this process because of its fast reoxidation reaction kinetics and considerable H2 yield. However, high temperatures (\u3e1550oC) are required to drive ceria reduction, making the reactor and the solar heat collector design challenging. Furthermore, a low steam oxidation temperature is preferred from a reactor energy balance stand-point. Please click Additional Files below to see the full abstract

Reduced grain chalkiness and its possible physiological mechanism in transgenic rice overexpressing l-GalLDH

AbstractChalkiness is one of the key factors determining rice quality and price. Ascorbic acid (Asc) is a major plant antioxidant that performs many functions in plants. l-Galactono-1,4-lactone dehydrogenase (l-GalLDH, EC1.3.2.3) is an enzyme that catalyzes the final step of Asc biosynthesis in plants. Here we show that the l-GalLDH-overexpressing transgenic rice, GO-2, which has constitutively higher leaf Asc content than wild-type (WT) plants, exhibits significantly reduced grain chalkiness. Higher foliar ascorbate/dehydroascorbate (Asc/DHA) ratios at 40, 60, 80, and 100days of plant age were observed in GO-2. Further investigation showed that the enhanced level of Asc resulted in a significantly higher ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) protein level in GO-2 at 80days. In addition, levels of abscisic acid (ABA) and jasmonic acid (JA) were lower in GO-2 at 60, 80, and 100days. The results we present here indicate that the enhanced level of Asc is likely responsible for changing redox homeostasis in key developmental stages associated with grain filling and alters grain chalkiness in the l-GalLDH-overexpressing transgenic by maintaining photosynthetic function and affecting phytohormones associated with grain filling