Keio University · Engineering
Professor Yuji Nagasaka's research lab specializes in the development and characterization of advanced thermal materials and measurement techniques for extreme environments, with a focus on space and high-performance engineering applications. The lab conducts precise thermophysical property measurements—particularly thermal conductivity, diffusivity, and effusivity—using advanced methods such as the transient hot-wire technique and photothermal radiometry. Research spans functional materials like variable emissivity coatings and functionally graded materials (FGMs), as well as aqueous electrolyte solutions under high pressure and temperature. The lab emphasizes accurate, absolute measurements to support the design of reliable thermal control systems for aerospace and energy applications.
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Abstract In recent planetary exploration space missions, spacecraft are exposed to severe thermal environments that are sometimes more extreme than those experienced in earth orbits. The development of advanced thermal control materials and devices together with reliable and accurate measurements of their thermophysical properties are needed for the development of systems designed to meet the engineering challenges associated with these space missions. We provide a comprehensive review of the st
Abstract The paper describes absolute measurements of the thermal conductivity of aqueous NaCl solutions in the concentration range 0 to 5 molality, the temperature range 0 to 80°C and the pressure range 0.1 to 40 MPa. An apparatus is based on the transient hot‐wire method using coated wire. The accuracy of the experimental results is estimated to be ± 0.5%. The results constitute the first measurements of the pressure effect on the thermal conductivity of NaCl solutions. The pressure coefficien
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPrecise measurements of the thermal conductivity of toluene and n-heptane by the absolute transient hot-wire methodYuji Nagasaka and Akira NagashimaCite this: Ind. Eng. Chem. Fundamen. 1981, 20, 3, 216–220Publication Date (Print):August 1, 1981Publication History Published online1 May 2002Published inissue 1 August 1981https://pubs.acs.org/doi/10.1021/i100003a006https://doi.org/10.1021/i100003a006research-articleACS PublicationsRequest reuse permission
We have developed a new apparatus to evaluate thermal duffusivity and thermal effusivity distributions of functionally graded materials (FGMs) by photothermal radiometry (PTR). Since this method is applicable to the low modulation frequency range down to 1 mHz, it is suitable for the measurement of thermally thick samples such as FGMs. We have solved heat conduction equations for a multi-layered model applicable to the present PTR measurement. The effects on the phase lag measurement caused by t
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