A 2.75-Approximation Algorithm for the Unconstrained Traveling Tournament Problem

A 2.75-approximation algorithm is proposed for the unconstrained traveling tournament problem, which is a variant of the traveling tournament problem. For the unconstrained traveling tournament problem, this is the first proposal of an approximation algorithm with a constant approximation ratio. In addition, the proposed algorithm yields a solution that meets both the no-repeater and mirrored constraints. Computational experiments show that the algorithm generates solutions of good quality.Comment: 12 pages, 1 figur

Effects of elasticity on wall shear stress in patient-specific aneurysm of cerebral artery

The behavior of wall shear stress (WSS) was previously reported in a deformable aneurysm model using fluid-structure interactions. However, these findings have not been validated. In the present study, we examined the effect of elasticity (i.e. , deformation) on wall shear stress inside a cerebral aneurysm at the apex of a bifurcation using particle image velocimetry in vitro. The flow model simulated a human patient-specific aneurysm at the apex of the bifurcation of the middle cerebral artery. Flow characteristics by wall elasticity were examined for both elastic and non-deformable aneurysm models with pulsatile blood flow. The absolute temporally- and spatially-averaged WSS along the bleb wall was smaller in the elastic model than that in the non-deformable model. This small WSS may be related to attenuation of the WSS. Further, the WSS gradient had a finite value near the stagnation point of the aneurysm dome. Finally, the WSS gradient near the stagnation point was slightly smaller in the elastic model than that in the non-deformable model. These data suggest that elasticity of the aneurysm wall can affect the progression and rupture of aneurysms via hemodynamic stress

Impurity emission characteristics of long pulse discharges in Large Helical Device

Line spectra from intrinsic impurity ions have been monitored during the three kinds of long-pulse discharges (ICH, ECH, NBI). Constant emission from the iron impurity shows no preferential accumulation of iron ion during the long-pulse operations. Stable Doppler ion temperature has been also measured from Fe XX, C V and C III spectra

Design of Metal-to-Metal Charge-Transfer Chromophores for Visible-Light Activation of Oxygen-Evolving Mn Oxide Catalysts in a Polymer Film

To construct photoresponsive unidirectional charge transfer units for the activation of oxygen-evolving manganese oxide (MnO_<i>x</i>) catalyst, metal-oxide nanoclusters consisting of cerium (Ce^III) or cobalt (Co^II) ions and Keggin-type polyoxotungstate (PW₁₂O₄₀^3–) were synthesized in a polymer matrix as visible-light-absorbing chromophores. The utilization of the polymer matrix enabled the molecularly dispersed PW₁₂O₄₀^3– states and was advantageous to achieve product-separable energy conversion systems. The reaction of PW₁₂O₄₀^3– with Ce­(NO₃)₃ or CoCl₂ in the polymer matrix generated the new broad absorption tails extending from the UV to visible region, assignable to metal-to-metal charge transfer (MMCT) transitions of oxo-bridged binuclear W^VI–O–Ce^III and W^VI–O–Co^II units. Cyclic voltammetry analysis of the oxo-bridged binuclear units in the polymer membrane revealed that the Co^III/Co^II couple had a 300 mV more positive redox potential than that of Ce^IV/Ce^III and was capable of extracting electrons from MnO_<i>x</i> catalyst. Although visible-light irradiation of the polymer membrane having W^VI–O–Co^II units resulted in negligible photocurrent generation, a clear anodic photocurrent response assigned to photoinduced W^VI–O–Co^II → W^V–O–Co^III transition was observed after the coupling of MnO_<i>x</i> catalysts to W^VI–O–Co^II units. This finding demonstrated that the generation of anodic photocurrent is derived from the activation of MnO_<i>x</i> catalyst by the photogenerated Co^III through confined W^VI–O–Co^II linkages. The system in this work based on POM and polymer, and its synthetic method provide us a novel methodology to develop artificial photosynthetic systems with spatially and energetically optimized components