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Japan Aerospace Exploration Agency (JAXA) has planned High-Mach Integrated Control Experiment (HIMICO), which is a flight experiment under hypersonic conditions. The ramjet engine used in the experimental aircraft is designed for self-ignition of the fuel to occur due to high temperature caused by aerodynamic heating in hypersonic flow. We confirmed that self-ignition occurred under some test conditions in the combustion test. However, conditions of the incoming air and the injected fuel where self-ignition occurred were not clear. In this study, we develop a chemically reacting flow solver for investigating the self-ignition. Large-eddy simulations of the combustor of the HIMICO engine are performed using a detailed hydrogen-air reaction mechanism. The results show that qualitative prediction whether self-ignition occurs is possible by Large-eddy simulations using the solver. In the simulations, self-ignition occurs even under conditions where self-ignition did not occur in the test. On the other hand, it is found that the selection of the boundary condition of the injector outer walls has a great effect on the time to self-ignition. For improving the accuracy of prediction, it is necessary to consider turbulence and three-dimensional flow due to the intake and the effects of heat exchange on the injector outer walls. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate a fibrous assembly of carbon nanotubes (CNTs) induced by a gas discharge breakdown that bridge the distance between two planar electrodes. To achieve this, we placed the two planar electrodes, one of which was covered with a CNT film, in a chamber; a vacuum pump was used to evacuate the air from the chamber and replace it with inert gas. By then applying a voltage between the electrodes, we induced a discharge breakdown between them. This caused the CNTs coated on the electrode surface to detach and form fibrous assemblies. The assemblies elongated and reached the opposite electrode, thereby creating bridges between the electrodes. These bridges formed when the gas pressure was greater than ca. 1.0×103Pa and in combination with the occurrence of a spark discharge. At lower pressures, a glow discharge occurred, and no bridge formation was observed, indicating that the discharge mode is critical for the bridge formation. [ABSTRACT FROM AUTHOR]

Systemic and cellular zinc homeostasis is elaborately controlled by ZIP and ZnT zinc transporters. Therefore, detailed characterization of their expression properties is of importance. Of these transporter proteins, Zip4 functions as the primarily important transporter to control systemic zinc homeostasis because of its indispensable function of zinc absorption in the small intestine. In this study, we closely investigated Zip4 protein accumulation in the rat small intestine in response to zinc status using an anti-Zip4 monoclonal antibody that we generated and contrasted this with the zinc-responsive activity of the membrane-bound alkaline phosphatase (ALP). We found that Zip4 accumulation is more rapid in response to zinc deficiency than previously thought. Accumulation increased in the jejunum as early as 1 day following a zinc-deficient diet. In the small intestine, Zip4 protein expression was higher in the jejunum than in the duodenum and was accompanied by reduction of ALP activity, suggesting that the jejunum can become zinc deficient more easily. Furthermore, by monitoring Zip4 accumulation levels and ALP activity in the duodenum and jejunum, we reasserted that zinc deficiency during lactation may transiently alter plasma glucose levels in the offspring in a sex-specific manner, without affecting homeostatic control of zinc metabolism. This confirms that zinc nutrition during lactation is extremely important for the health of the offspring. These results reveal that rapid Zip4 accumulation provides a significant conceptual advance in understanding the molecular basis of systemic zinc homeostatic control, and that properties of Zip4 protein accumulation are useful to evaluate zinc status closely. [ABSTRACT FROM AUTHOR]