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Fumoto K.,National Institute of Technology, Kushiro College | Kawaji M.,University of Toronto | Kawanami T.,Kobe University
Journal of Electronic Packaging, Transactions of the ASME | Year: 2010

This paper discusses a pulsating heat pipe (PHP) using a self-rewetting fluid. Unlike other common liquids, self-rewetting fluids have the property that the surface tension increases with temperature. The increasing surface tension at a higher temperature can cause the liquid to be drawn toward a heated surface if a dry spot appears and thus to improve boiling heat transfer. In experiments, 1-butanol and 1-pentanol were added to water at a concentration of less than 1 wt % to make self-rewetting fluid. A pulsating heat pipe made from an extruded multiport tube was partially filled with the self-rewetting fluid water mixture and tested for its heat transport capability at different input power levels. The experiments showed that the maximum heat transport capability was enhanced by a factor of 4 when the maximum heater temperature was limited to 110°C. Thus, the use of a self-rewetting fluid in a PHP was shown to be highly effective in improving the heat transport capability of pulsating heat pipes. © 2008 IEEE. Source

Sako A.,National Institute of Technology, Kushiro College
Advances in Mathematical Physics | Year: 2010

We review recent developments in noncommutative deformations of instantons in ℝ4. In the operator formalism, we study how to make noncommutative instantons by using the ADHM method, and we review the relation between topological charges and noncommutativity. In the ADHM methods, there exist instantons whose commutative limits are singular. We review smooth noncommutative deformations of instantons, spinor zero-modes, the Green's functions, and the ADHM constructions from commutative ones that have no singularities. It is found that the instanton charges of these noncommutative instanton solutions coincide with the instanton charges of commutative instantons before noncommutative deformation. These smooth deformations are the latest developments in noncommutative gauge theories, and we can extend the procedure to other types of solitons. As an example, vortex deformations are studied. Copyright © 2010 Akifumi Sako. Source

Miyake A.,National Institute of Technology, Kushiro College | Miyake A.,Meiji Gakuin University | Ohta K.,Meiji Gakuin University | Sakai N.,Tokyo Womans Christian University
Progress of Theoretical Physics | Year: 2011

We evaluate volume of moduli space of BPS vortices on a compact genus h Riemann surface σh by using topological field theory and localization technique developed by Moore, Nekrasov and Shatashvili. We apply this technique to Abelian (ANO) vortex and show that the volume of moduli space agrees with the previous results obtained by integrating over the moduli space metric. We extend the evaluation to non-Abelian gauge groups and multiflavors. We also compare our results with the volume of the Kähler quotient space inspired by the brane configuration. Source

Ishibashi N.,University of Tsukuba | Murakami K.,National Institute of Technology, Kushiro College
Journal of High Energy Physics | Year: 2016

Abstract: It is possible to formulate light-cone gauge string field theory in noncritical dimensions. Such a theory corresponds to conformal gauge worldsheet theory with nonstandard longitudinal part. We study the longitudinal part of the worldsheet theory on higher genus Riemann surfaces. The results in this paper shall be used to study the dimensional regularization of light-cone gauge string field theory. © 2016, The Author(s). Source

Kishi N.,National Institute of Technology, Kushiro College | Mikami H.,Sumitomo Mitsui Construction
ACI Structural Journal | Year: 2012

To establish an impact-resistant design procedure for reinforced concrete (RC) structures based on the performance-based design concept, an evaluation method for the impact-resistant capacity of the structures needs to be developed. Until now, a particular method for beams has not yet been specified worldwide. To achieve this, falling-weight impact tests on a total of 36 beams with varying section parameters were conducted and the key factors for better representing the impact behavior of the beams were investigated. Two empirical equations were derived based on the experimental results. By using these equations, the required static flexural load-carrying capacity of an RC beam may be determined by specifying the limit state with the maximum and residual deflections of the beam. Copyright © 2012, American Concrete Institute. All rights reserved. Source

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