Propagation of Electrostatic Waves near the Lower Hybrid Frequency in a Toroidal Plasma, NOVA-I

Resonance cones in a lower hybrid range of frequency are observed and confirmed under the combined influence of toroidicity and inhomogenity in a toroidal device NOVA-I. The resonance cone is investigated in two different plasma sources, i.e. (A) a steady plasma of low density (Nₑ, ～5×10⁹ cm⁻³), and (B) a pulsed tokamak plasma of high density (Nₑ～2×10¹³ cm⁻³). In case (A), the experimental results agree well with the trajectories computed from a simple cold plasma dispersion relation. Even in the high density tokamak plasma of case (B), a wave penetration toward the plasma center is observed and its behavior also agrees qualitatively with the thoery

Heat Transfer by Natural Convection in Laminar Boundary Layer on Vertical Flat Wall

In this paper, we have studied theoretically the heat transfer by laminar natural convection from a bot vertical flat wall to the surrounding fluid. This problem has already been theoretically studied by Pohlhausen, but his method is very troublesome and since he uses Schmidt and Beckmann's experimental results for air, Pohlhausen's solution is not applicable to other kinds of fluids except air. We have analysed this problem for gas and liquid by means of three different approximate methods, and compared each result with the other

An Experimental Study of Bubble Motion on a Heating Surface in Nucleate Boiling

This paper deals with some results of the observations of bubble formation and growth in nucleate boiling on a horizontal heating surface immersed in water under atmospheric pressure by using a high-speed camera. Experimental data are compared with Zuber's or Griffith's analytical results for the prediction of bubble growth rate. Some discussions are also presented for the preparing period and the growing period of one cycle of bubbling

Buoyancy Effects on Forced Convection Flow and Heat Transfer

Buoyancy effects on a forced convection laminar flow with uniform internal heat generation along a vertical flat plate are theoretically studied. Solutions are obtained by means of the integral equation method (the approximate Kármán-Pohlhausen method) and are compared with the solutions obtained by the series expansion method in which the stream function and the temperature function are expanded into power series in terms of the parameter Gr/Re for Pr≧l, whereas in terms of the parameter Gr/(RePr) for Pr<1. Velocity and temperature distributions of fluid are presented for various values of the governing parameters

An Analytical Study of Heat Transfer in Nucleate Boiling

This paper deals with a theoretical prediction of heat transfer in a steady state nucleate boiling by applying the theory which was developed for the incidence of the first bubble in transient boiling. The predictions are compared with experimental data or empirical correlations of water and Neo SK oil ♯ 350 (mixture of terphenyls). Some discussion is also presented for the preparing period of one cycle of bubbling

Statistical Analysis of Pressure Fluctuations in Vertical Two-Phase Flow

An experimental study was conducted on pressure fluctuations in vertical two-phase air-water flow. Statistical analysis of measured fluctuations was used to identify flow regimes in two-phase flow. Random ripple fluctuations were observed in bubbly flow. In slug and churn flows, however, violent oscillations were caused by the periodic passage of liquid and gas slugs. These oscillations-were weakened with a further in-crease of gas flowrate, and small ripple fluctuations again appeared in annular flow

Identification of a Cytokine-induced Antiapoptotic Molecule Anamorsin Essential for Definitive Hematopoiesis

Many growth factors and cytokines prevent apoptosis. Using an expression cloning method, we identified a novel antiapoptotic molecule named Anamorsin, which does not show any homology to known apoptosis regulatory molecules such as Bcl-2 family, caspase family, or signal transduction molecules. The expression of Anamorsin was completely dependent on stimulation with growth factors such as interleukin 3, stem cell factor, and thrombopoietin in factor-dependent hematopoietic cell lines, and forced expression of Anamorsin conferred resistance to apoptosis caused by growth factor deprivation in vitro. Furthermore, Anamorsin was found to act as an antiapoptotic molecule in vivo because Anamorsin−/− mice die in late gestation due to defective definitive hematopoiesis in the fetal liver (FL). Although the number of hematopoietic stem/progenitor cells in the FL did not decrease in these mice, myeloid, and particularly erythroid colony formation in response to cytokines, was severely disrupted. Also, Anamorsin−/− erythroid cells initiated apoptosis during terminal maturation. As for the mechanism of Anamorsin-mediated cell survival, a microarray analysis revealed that the expression of Bcl-xL and Jak2 was severely impaired in the FL of Anamorsin−/− mice. Thus, Anamorsin is considered to be a necessary molecule for hematopoiesis that mediates antiapoptotic effects of various cytokines