Graph construction with the maximum number of trees by continuous edge addition

A simple computational algorithm is presented to construct a graph with the maximum number of trees by adding edges one by one. The number of trees of a graph would become an index to estimate the overall reliability of probabilistic communication networks with the same link probabilities. Our procedure, Max-trees, selects one edge that gives the maximum number of trees among edges not included in the original graph. This process is continuously repeated at each step of adding an edge, when we get the sequence of new edges to be added. As examples of the execution results, the edge sequence and the maximum number of trees are shown for two types of starting graph, which are a tree of series edges and a star-shaped tree for nodes n = 7 and 8. To see how many trees these graphs have, the minimum numbers of trees for graphs with the same number of nodes and edges are similarly calculated by the minimum-version algorithm Min-trees. An edge sequence of Max-trees makes long cycles, and that of Min-trees makes cycles of three for as long as possible. The ratio of the maximum number of trees to the minimum number of trees is about 1 to 6 for these examples. This work was presented in part at the 11th International Symposium on Artificial Life and Robotics, Oita, Japan, January 23–25, 2006     

Identification and Field Evaluation of Sex Pheromone Components of the Pear Barkminer Moth, <Emphasis Type="Italic">Spulerina astaurota</Emphasis>

The pear barkminer moth, Spulerina astaurota Meyrick (Gracillariidae: Gracillariinae), is a harmful pest of the Asian-pear tree. Pheromone components of the female were analyzed by gas chromatography (GC) with an electroantennographic (EAG) detector and GC coupled with mass spectrometry. The analyses of a crude pheromone extract and those of a fractionated extract on a Florisil column indicated three EAG-active components, tetradecadien-1-ol, its acetate, and an aldehyde derivative. Characteristic fragment ions in the mass spectra of the dienyl compounds and derivatives with 4-methyl-1,2,4-triazoline-3,5-dione revealed double bonds at the 9- and 11-positions. By comparing the chromatographic behaviors to those of four authentic geometrical isomers, which were synthesized by three different routes starting from 1,8-octanediol or 1,9-nonanediol, the configuration of each natural component was assigned to be 9Z,11Z; i.e., it was concluded that the S. astaurota females secreted (9Z,11Z)-9,11-tetradecadien-1-ol (Z9,Z11-14:OH) as a main pheromone component, and the acetate and aldehyde derivatives (Z9,Z11-14:OAc and Z9,Z11-14:Ald) as minor components. This identification was confirmed by a field evaluation of the synthetic pheromone. While the male moths could be attracted to a lure baited with Z9,Z11-14:OH alone, Z9,Z11-14:OAc showed a strong synergistic effect on the attraction. Among the lures tested, the mixture of alcohol and acetate in a ratio of 7:3 exhibited the strongest attraction. Addition of Z9,Z11-14:Ald in the mixture did not significantly increase the number of males attracted. Furthermore, the field test indicated that some contamination of a geometrical isomer of the alcohol did not impair the activity of the binary mixture with the 9Z,11Z configuration.     

Internal gravity wave resonance of thermal convection fields in a square cavity with heat‐flux vibration

In this paper, the thermal convection field and its resonance phenomena in a square cavity with sinusoidal heat‐flux vibration were numerically investigated. As the angular velocity ω is changed, the thermal convection field at Pr = 0.71,Ra = 10⁶ is found to be classified into 5 regions. In particular, the field has the local maximum relative amplitude of midplane Nusselt's number at ω_c = 350, which corresponds to the angular velocity of internal gravity wave ω_r estimated by a theoretical equation proposed by Thorpe. This shows that the local enhancement is induced by internal gravity wave resonance. Such correspondence is observed for Ra ≥ 10⁵,Ra ≥ 10⁶ for Pr = 0.71, 7.1, respectively. For these ranges of Ra we propose a correlation equation, a function of Pr and Gr only, to estimate the resonant angular velocity. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(5): 309–322, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20122     

Quasi‐static and chaotic characteristics of the natural convection field between concentric vertical annuli

In this study unsteady and chaotic characteristics of thermal convection fields between concentric annuli were experimentally examined, and they were compared with those reported in a vertical slot. The inner cylinder was heated by an embedded heater and the outer one was cooled by temperature‐controlled cold water, and 84 wt% glycerol‐water solution was used for the present test liquid. The main results are as follows: (1) The region where the characteristic frequency of temperature fluctuation is detected is located in the upper portion of the region where the secondary cells exist. (2) The time scale of the temperature change at which the autocorrelation coefficient becomes 1/e is relatively small in the secondary‐cell region, and this corresponds to the result of the natural convection field in a vertical slot. (3) The significant chaotic characteristics of temperature fluctuation are observed in almost the same region where the characteristic frequency of temperature fluctuation is detected, and this also corresponds to the results on the vertical slot. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(6): 486–497, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10048     

雄胜高温岩体地热开发的数值计算进展

主要介绍日本电力中央研究所为秋田县雄胜高温岩体地热开发试验项目——近年开发的热-水流动藕合数值计算源程序GEOTH3D的原理、特点、应用现状和尚待改善的一些问题，并结合国际上其他相关软件的进展情况，对下一步可能的工作倾向进行了探讨。