Inhomogeneity of currents in a wire array during its explodingphase

The current in a wire array during its exploding phase has been studied. The wire array consisting of many thin wires is used as a plasma source in a z-pinch X-ray radiation system. The current distribution in the exploding wire array plays an important role in producing an initial symmetrical plasma. In the present experiment, four tungsten wires of 0.1 mm in diameter were exploded in a vacuum. The experiment was carried out with an inductive voltage adder pulsed power generator providing a current of 160 kA at quarter period of 1.8 μs The currents through and the voltage across the wires were measured simultaneously. It was found that the currents in the wires were inhomogeneous, especially after the wires became plasma. Once the currents became inhomogeneous, the inhomogeneity remained throughout the discharge. It was also studied how the dimensions of the wires affected the homogeneity of the currents. Wires of different lengths or different cross sectional areas resulted in strong inhomogeneities of the currents. The wires with shorter length or smaller cross-sectional area became plasmas earlier than other wires. Thus, the resistances of the wires were not equal. These differences in the resistance caused the inhomogeneity of the currents     

An improved method for synthesis of 4,4-dimethylpyrazolone and application to dihydropyridazinone ring formation

An improved method for 4,4-dimethylpyrazolone synthesis with t-butylcarbazate was described. The applicability of this method to dihydropyridazinone formation was demonstrated. This method is useful for suppressing the side reaction caused by the high nucleophilicity of hydrazine.     

Temperature-responsive ionic liquid/water interfaces: relation between hydrophilicity of ions and dynamic phase change

Phase separation between ionic liquids (ILs) and molecular liquids is of interest physico-chemically, and also has industrial relevance. IL/water mixtures are of great interest in many fields. Unlike static phase separation between IL and water, dynamic shifts of IL/water mixtures between a homogeneous mixture and separate phases have a wide variety of applications. The miscibility of ILs with water generally increases upon heating, and a few ILs undergo a lower critical solution temperature (LCST)-type phase transition with water in which the separated biphases become miscible upon cooling. As the phase transition is controlled by changing the temperature by a few degrees, the LCST-type phase response of IL/water mixtures makes it possible to use ILs as solvents in various energy-saving processes. Since many hydrophilic ILs do not undergo phase separation with water, we aim to determine the necessary conditions under which hydrophobic ILs undergo the phase transition. Based on physico-chemical analysis of many hydrophobic ILs that undergo a phase separation after mixing with water, we find there is a particular range of "hydrophilicity" of these hydrophobic ILs within which the LCST-type phase transition is possible. Accordingly, a hydrophilicity index (HI) of ILs is proposed, in terms of the number of water molecules in the separated IL phase. The HI value proves to be a good indicator of the phase behaviour of IL/water mixtures, as well as their phase transition temperature. Potential application of the LCST-type phase change to the selective extraction of water-soluble proteins is also summarised.     

Estimation of Critical Point in Branching Reactions: Further Examination of Gel Point Formula

The theory of gel point in real polymer solutions is examined with the empirical correlation between the reciprocal of the percolation threshold and the coordination number given by the percolation theory. Applying a larger value of the relative frequency of cyclization, an excellent agreement is obtained between the present theory and the percolation result. This suggest that while the ring distribution on lattices is similar to that in real systems, ring production is more frequent in the lattice model than in real systems. To confirm this conjecture, we derive the ring distribution function of the lattice model as a limiting case of d→∞, and show that the solution is in fact identical to the asymptotic formula of C→∞ in real systems except for the coefficient C, which has a maximum at d = 5, in support of the above conjecture. To examine the validity of the asymptotic solution for the lattice model, we apply it to the critical point problem of the percolation theory, showing that the solution works well in high dimensions greater than six.     

Retracted and replaced: a flow‐condition‐based interpolation finite element procedure for triangular grids

The following article from the International Journal for Numerical Methods in Fluids ‘A flow‐condition‐based interpolation finite element procedure for triangular grids’ by Haruhiko Kohno and Klaus‐Jürgen Bathe published online on 3 August 2005 in Wiley InterScience ( www.interscience.wiley.com ) and in print on 10 October 2005 in the International Journal for Numerical Methods in Fluids Volume 49 Issue 8 pp. 849–875 has been retracted and replaced by agreement between the authors, the journal editors and John Wiley & Sons, Ltd. The article has been retracted due to printing errors which have been corrected in the replacement article.(DOI: 10.1002/fld.1246 )     

Warm ocean water intrusion into Kagoshima Bay

From the field observations and the buoy robot data, the warm ocean water is known to intrude into Kagoshima Bay intermittently in winter. We first visualize these phenomena using some satellite thermal infrared images. Then the numerical analysis is performed employing a multi-level finite difference method (FDM). It is found from the numerical analysis that the intrusion occurs when the warm water comes into touch with the bay water at the mouth of the bay. The calculated warm water distribution in the bay is similar to the satellite images and the velocity of the intrusion is the same order with the ones estimated by the buoy robot data and the satellite images. The intrusion occurs even without the tidal effect, the role of the tide is only to rectify some warm water distribution in the bay.     

Exploration of novel predictive markers in rat plasma of the early stages of chronic renal failure

To identify blood markers for early stages of chronic kidney disease (CKD), blood samples were collected from rats with adenine-induced CKD over 28 days. Plasma samples were subjected to metabolomic profiling by liquid chromatography-mass spectrometry, followed by multivariate analyses. In addition to already-identified uremic toxins, we found that plasma concentrations of N6-succinyl adenosine, lysophosphatidylethanolamine 20:4, and glycocholic acid were altered, and that these changes during early CKD were more sensitive markers than creatinine concentration, a universal indicator of renal dysfunction. Moreover, the increase in plasma indoxyl sulfate concentration occurred earlier than increases in phenyl sulfate and p-cresol sulfate. These novel metabolites may serve as biomarkers in identifying early stage CKD.