1. |
Naoya Sakoda, Jiang Shiheng, Masamichi Kohno, Shigeru Koyama, Yukihiro Higashi, Yasuyuki Takata, Gaseous PVT property measurements of cis-1,3,3,3-tetrafluoropropene, *Journal of Chemical and Engineering Data*, Accepted, 2017.06. |

2. |
Naoya Sakoda, Jiang Shiheng, Masamichi Kohno, Yasuyuki Takata, Yukihiro Higashi, Vapor-Liquid Equilibrium Measurements of HFO Refrigerant Mixtures , *5th IIR International Conference on Thermophysical Properties and Transfer Processes of Refrigerants (TPTPR2017)*, PAPER ID 108, 2017.04. |

3. |
N. Sakoda, K. Onoue, T. Kuroki, K. Shinzato, M. Kohno, M. Monde, Y. Takata, Transient Temperature and Pressure Behavior of High-Pressure 100 MPa Hydrogen during Discharge through Orifices, *International Journal of Hydrogen Energy*, 41, 17169-17174, 2016.08. |

4. |
N. Sakoda, T. Hisatsugu, K. Furusato, K. Shinzato, M. Kohno, Y. Takata, Viscosity Measurements of Hydrogen at High Temperatures up to 573 K by a Curved Vibrating Wire Method, *The Journal of Chemical Thermodynamics*, 89, 22-26, 2015.05. |

5. |
N. Sakoda, R. Kumagai, R. Ishida, M. Kohno, Y. Takata, Vacuum Generation by Hydrogen Permeation to Atmosphere through Austenitic and Nickel-Base-Alloy Vessel Walls at Temperatures from 573 K to 773 K , *International Journal of Hydrogen Energy*, 39, 21, 11316-11320, 2014.06. |

6. |
吉村幸祐, 上原帝臣, 新里 寛英, 久次達也, 迫田 直也, 河野 正道, 高田 保之, 振動細線法による気体の粘性係数測定装置の開発, *熱物性*, 28, 1, 15-21, 2014.02. |

7. |
Naoya Sakoda, Masamichi Kohno, Yasuyuki Takata, Thermodynamic Behavior of Hydrogen Binary Systems with Critical Curve Divergence and Retrograde Condensation, *Journal of Thermal Science and Technology*, 8, 3, 603-612, 2013.11, In binary systems of hydrogen and hydrocarbons, the fluid-phase thermodynamic behavior is unique in having the divergence of the critical curves to a high pressure region. The thermodynamic properties of the binary systems including hydrogen with methane, ethane, propane, and carbon dioxide were calculated from a Peng-Robinson equation of state (PR EOS). The mixing parameter of the present EOS has a functional form of temperature generalized by the critical temperatures of the hydrocarbons and carbon dioxide. Based on the corresponding states principle, the coefficients of the parameter were determined with a non-linear least squares fitting to the experimental critical points of the mixtures. The developed PR EOS shows good agreement with the experimental data of not only the critical points but also the phase equilibria. In the hydrogen binary systems, retrograde condensation is expected. The volumetric and enthalpy changes in this process were simulated for a hydrogen + carbon dioxide mixture of 0.55 mole fraction using the PR EOS at 270 K.. |

8. |
吉村幸祐, 上原帝臣, 新里 寛英, 迫田 直也, 久次達也, 河野 正道, 高田 保之, 振動細線法による気体の粘性係数測定装置の開発, *熱物性*, 高圧・高温の条件下における水素の粘性係数を測定することを目的とし，少量の試料で測定可能な振動細線法を用いた粘性係数測定装置を1 MPa以下の低圧域を対象として新たに開発した．本研究で採用した振動細線法では磁場中に設置した半円型ワイヤに交流電流を流し，その振動の減衰と気体の粘性の関係から粘性係数を算出する方法である．半円型ワイヤにはタングステン，磁石はサマリウムコバルトを使用した．この装置を用いて，室温と50 ºC，圧力1 MPa以下の条件で，測定の重要なパラメータである内部摩擦係数を決定した後，窒素，ヘリウムおよび水素の粘性係数を測定した．. |

9. |
迫田直也，本村晃一，Supriatno，新里寛英，河野正道，高田保之，藤井丕夫, 高温高圧水素用定容積式PVT性質測定装置の開発, *熱物性*, Vol. 26, 86-91, 2012.04, 473 K～773 K，100 MPaまでの温度，圧力領域において水素のPVT性質測定を目的とした定容積法による装置を開発した．水素は密度が非常に小さいため，試料容器内(250 cc)に充填された試料の質量を精度良く測定することは困難である．そこで本研究では，内容積の大きな膨張容器(2500 cc)を別途設置し，これに試料を膨張させることで充填密度を決定する気体膨脹法を組み合わせた．開発した装置を用いて窒素のPVT性質を473 K～773 K, 100 MPaまで測定し，信頼性の高い既存の状態方程式と比較した結果，0.1 %以内で良好に一致した．そして，水素を473 Kで100 MPaまで測定した．本測定データは過去にバーネット法で測定して得られたデータと0.1 %以内で一致した．. |

10. |
N. Sakoda, K. Shindo, K. Motomura, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Burnett PVT Measurements of Hydrogen and the Development of a Virial Equation of State at Pressures up to 100 MPa, *International Journal of Thermophysics*, Vol. 33, 381-395, 2012.03, PVT properties were measured for hydrogen by the Burnett method in the temperature range from 353 K to 473 K and at pressures up to 100 MPa. In the present Burnett method, the pressure measurement was simplified by using an absolute pressure transducer instead of a differential pressure transducer, which is traditionally used. The experimental procedures become easier, but the absolute pressure transducer is set outside the constant temperature bath because of the difficulty of its use in the bath, and the data acquisition procedure is revised by taking into account the effects of the dead space in the absolute pressure transducer. The measurement uncertainties in temperature, pressure, and density are 20 mK, 28 kPa, and 0.07 % to 0.24 % (k = 2), respectively. Based on the present data and other experimental data at low temperatures, a virial equation of state (EOS) from 220 K to 473 K and up to 100 MPa was developed for hydrogen with uncertainties in density of 0.15 % (k = 2) at P ≤ 15 MPa, 0.20 % at 15 MPa < P ≤ 40 MPa, and 0.24 % at P > 40 MPa, and this EOS shows physically reasonable behavior of the second and third virial coefficients. Isochoric heat capacities were also calculated from the virial EOS and were compared with the latest EOS of hydrogen. The calculated isochoric heat capacities agree well with the latest EOS within 0.5 % above 300 K and up to 100 MPa, while at lower temperatures, as the pressure increases, the deviations become larger (up to 1.5 %).. |

11. |
N. Sakoda, K. Shindo, K. Motomura, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Burnett Method with Absolute Pressure Transducer and Measurements for PVT Properties of Nitrogen and Hydrogen up to 473 K and 100 MPa, *International Journal of Thermophysics*, Vol. 33, 6-21, 2012.01, A measurement method for PVT properties of high-temperature and high-pressure gases was developed by simplifying the Burnett method and revising the data acquisition procedure. Instead of a differential pressure transducer, which is traditionally used, an absolute pressure transducer is used in the present method, and the measurement of pressure becomes easier. However, the absolute pressure transducer is placed outside the constant temperature bath because of the difficulty of its use in high-temperature surroundings, and some parts with different temperatures from the sample vessels exist as dead space. The present method takes into account the effect of the dead space in the data acquisition procedure. Nitrogen was measured in the temperature range from 353 K to 473 K and at pressures up to 100 MPa to determine the apparatus constants, and then, hydrogen was measured at 473 K and up to 100 MPa. The determined densities are in agreement within uncertainties of 0.07% to 0.24% (k = 2), both with the latest equation of state and existing measured data.. |

12. |
A. Widyaparaga, M. Kuwamoto, N. Sakoda, M. Kohno, Y. Takata, Theoretical and Experimental Study of a Flexible Wiretype Joule-Thomson Microrefrigerator for Use in Cryosurgery, *Transactions of the ASME, Journal of Heat Transfer*, Vol. 134, 020903-1 - 020903-7, 2012.02, We have developed a model capable of predicting the performance characteristics of a wiretype Joule–Thomson microcooler intended for use within a cryosurgical probe. Our objective was to be able to predict cold tip temperature, temperature distribution, and cooling power using only inlet gas properties as input variables. To achieve this, the model incorporated gas equations of state to account for changing gas properties due to heat transfer within the heat exchanger and expansion within the capillary. In consideration of inefficiencies, heat in-leak from free convection and radiation was also considered and the use of a 2D axisymmetric finite difference code allowed simulation of axial conduction. To validate simulation results, we have constructed and conducted experiments with two types of microcoolers differing in inner tube material, poly-ether-ether-ketone (PEEK) and stainless steel. The parameters of the experiment were used in the calculations. CO2was used as the coolant gas for inlet pressures from 0.5 MPa to 2.0 MPa. Heat load trials of up to 550 mW along with unloaded trials were conducted. The temperature measurements show that the model was successfully able to predict the cold tip temperature to a good degree of accuracy and well represent the temperature distribution. For the all PEEK microcooler in a vacuum using 2.0 MPa inlet pressure, the calculations predicted a temperature drop of 57 K and mass flow rate of 19.5 mg/s compared to measured values of 63 K and 19.4 mg/s, therefore, showing that conventional macroscale correlations can hold well for turbulent microscale flow and heat transfer as long as the validity of the assumptions is verified.. |

13. |
A. Widyaparaga, T. Koshimizu, E. Noda, N. Sakoda, M. Kohno, Y. Takata, The Frequency Dependent Regenerator Cold Section and Hot Section Positional Reversal in a Coaxial Type Thermoacoustic Stirling Heat Pump, *Cryogenics*, Vol. 51, 591-597, 2011.10, We have constructed and tested two travelling wave thermoacoustic heat pumps using a coaxial configuration with the regenerator positioned in the annulus. We discovered a frequency dependent positional reversal of the cold section and hot section of the regenerator within the test frequency range. By decomposing the measured pressure wave within the annulus, we obtained the positive (w+) and negative (w−) propagating travelling waves. It has been revealed the change of frequency is accompanied by a change in magnitudes of w+ and w− which is in part influenced by the presence of travelling wave attenuation through the regenerator. The resulting change of dominant travelling wave on a given end of the regenerator will then change the direction of thermoacoustic heat pumping at that end. This will alter the regenerator temperature distribution and may reverse the cold and hot sections of the regenerator. As the reversal does not require additional moving parts, merely a change in frequency, this feature in coaxial travelling wave devices has tremendous potential for applications which require both heating and cooling operation.. |

14. |
迫田直也, 尾上清明, 高田保之, 車載水素容器の亀裂発生時における圧力変化の解析, *水素エネルギーシステム*, Vol. 36, 32-36, 2011.09, Thermodynamic simulation on the transient of pressure and temperature of an in-vehicle hydrogen container with the hydrogen leak from a crack was performed. It is assumed that the volume of the container is 40 L, which is filled with hydrogen at 70 MPa and 50 ºC as an initial condition, and the crack area is 1 mm2 or 10 mm2. Hydrogen at 70 MPa and -40 ºC is supplied from a refueling station with the flow rate of 2 kg/min or 6 kg/min. Conservation equations of mass and energy were solved using a thermophysical property database compiling an accurate equation of state. Moreover, the results were compared with those calculated by the ideal gas equation of state. It was found that the pressure of the real gas decreases more rapidly than that of the ideal gas.. |

15. |
A. Widyaparaga, M. Kuwamoto, A. Tanabe, N. Sakoda, H. Kubota, M. Kohno, Y. Takata, Study on a Wire-type Joule Thomson Microcooler with a Concentric Heat Exchanger, *Applied Thermal Engineering*, Vol. 30, 2563-2573, 2010.11, This study examines the performance of a wire-type Joule Thomson microcooler utilizing a flexible concentric counterflow heat exchanger. Three gases: C2H4, CO2 and N2 were used separately for trials conducted at inlet pressures ranging from 0.5 MPa to 5 MPa with C2H4 having the best performance. During unloaded tests at an inlet pressure of 2.0 MPa, C2H4 obtained a minimum temperature of 225 K while CO2obtained a minimum temperature of 232 K. Using CO2 the microcooler was able to maintain a temperature of 273 K at 100 mW heat input and 2 MPa inlet pressure. An inlet pressure of 3 MPa allowed a 550 mW heat input at 273 K. Theoretical performance calculations were conducted and compared to experimental results revealing considerable reduction of microcooler performance due to the presence of heat in-leak. Results have displayed that the JT coefficient of the coolant gas is a more dominant factor than heat transfer properties in determining the performance of the coolant. Due to the microscale of the device, relevant scaling effects were evaluated, particularly entrance effects, surface roughness and axial conduction.. |

16. |
迫田直也，進藤健太，新里寛英，河野正道，高田保之，藤井丕夫, 高圧水素用バーネット式PVT性質測定装置の開発, *熱物性*, Vol. 24, 28-34, 2010.02, 高圧水素のPVT性質測定を目的として，常温から523 K，100 MPaまでの温度，圧力領域で測定可能なバーネット式PVT性質測定装置を開発した．本測定装置は安全かつ効率的に実験を行うため，試料の昇圧から測定まで，全て遠隔で操作できるように設計されている．窒素のPVT性質を353 Kにおいて100 MPaまで測定し，既存の状態方程式と比較した結果，0.22 %以内で良好に一致した．そして，同様に353 Kにおいて水素のPVT性質を100 MPaまで測定することができ，既存の水素の状態方程式は本実測値と0.22 %以内で一致した．. |

17. |
N. Sakoda, K. Shindo, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Review of the Thermodynamic Properties of Hydrogen Based on Existing Equations of State, *International Journal of Thermophysics*, Vol. 31, 276-296, 2010.02, Currently available equations of state (EOSs) for hydrogen are reviewed, and the data for the critical point, normal boiling point, and triple point are summarized. Through comparisons of PVT, saturated properties, heat capacity, and speed of sound among the latest EOSs for hydrogen, their features are discussed. The proper use of the EOSs, including a consideration of the nuclear isomers (ortho- and parahydrogen), is of great importance, especially for saturated properties, heat capacity, and speed of sound because these properties are different between the nuclear isomers. The present review concludes with recommendations for use of the EOSs for hydrogen.. |

18. |
N. Sakoda, M. Uematsu, A Thermodynamic Property Model for the Binary Mixture of Methane and Hydrogen Sulfide, *International Journal of Thermophysics*, Vol. 26, 1303-1325, 2005.11, A thermodynamic property model with new mixing rules using the Helmholtz free energy is presented for the binary mixture of methane and hydrogen sulfide based on experimental PρTx data, vapor–liquid equilibrium data, and critical-point properties. The binary mixture of methane and hydrogen sulfide shows vapor–liquid–liquid equilibria and a divergence of the critical curve. The model represents the existing experimental data accurately and describes the complicated behavior of the phase equilibria and the critical curve. The uncertainty in density calculations is estimated to be 2%. The uncertainty in vapor–liquid equilibrium calculations is 0.02 mole fraction in the liquid phase and 0.03 mole fraction in the vapor phase. The model also represents the critical points with an uncertainty of 2% in temperature and 3% in pressure. Graphical and statistical comparisons between experimental data and the available thermodynamic models are discussed. |

19. |
N. Sakoda, M. Uematsu, Thermodynamic Properties of the Binary Mixture of Methane and Hydrogen Sulfide, *Zeitschrift für Physikalische Chemie*, Vol. 219, 1299-1319, 2005.09, From the interest of the thermodynamic properties for natural gas system, we have developed the thermodynamic property model for the binary mixture of methane and hydrogen sulfide system by the Helmholtz free energy function. Our model represents divergence of the critical curve and vapor–liquid–liquid equilibrium of this system as well as thermodynamic properties with high accuracy. The behavior of critical curve and phase equilibrium is discussed in detail with comparison of that for the mixture of methane and ethane system. Thermodynamic properties of methane and hydrogen sulfide system have been calculated using our model and their behavior as a function of composition is also reported.. |

20. |
N. Sakoda, M. Uematsu, A Thermodynamic Property Model for Fluid Phase Hydrogen Sulfide, *International Journal of Thermophysics*, Vol. 25, 709-737, 2004.05, A Helmholtz free energy equation of state for the fluid phase of hydrogen sulfide has been developed as a function of reduced temperature and density with 23 terms on the basis of selected measurements of pressure–density–temperature (P, r, T), isobaric heat capacity, and saturation properties. Based on a comparison with available experimental data, it is recognized that the model represents most of the reliable experimental data accurately in the range of validity covering temperatures from the triple point temperature (187.67 K) to 760 K at pressures up to 170 MPa. The uncertainty in density calculation of the present equation of state is 0.7% in the liquid phase, and that in pressure calculation is 0.3% in the vapor phase. The uncertainty in saturated vapor pressure calculation is 0.2%, and that in isobaric heat capacity calculation is 1% in the liquid phase. The behavior of the isobaric heat capacity, isochoric heat capacity, speed of sound, and Joule–Thomson coefficients calculated by the present model shows physically reasonable behavior and those of the calculated ideal curves also illustrate the capability of extending the range of validity. Graphical and statistical comparisons between experimental data and the available thermodynamic models are also discussed.. |

21. |
N. Sakoda, K. Motomura, Supriatno, Y. Fukatani, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Development of Apparatuses for PVT Properties of Hydrogen and Measurements at High Temperatures and High Pressures, *Book of Abstracts, 19th European Conference on Thermophysical Properties*, 298, 2011.08. |

22. |
A. Widyaparaga, M. Kuwamoto, E. Noda, N. Sakoda, M. Kohno, Y. Takata, Analytical Optimization of Heat Exchanger Dimensions of a Joule-Thomson Microcooler, *9th International Conference on Nanochannels, Microchannels and Minichannels*, 2011.06. |

23. |
M. Kuwamoto, A. Widyaparaga, N. Sakoda, M. Kohno, Y. Takata, Effect of Working Gas and Heat Exchanger Dimensions on Joule Thomson Microcooler Performance, *International Symposium on Innovative Materials for Processes in Energy Systems 2010, For Fuel Cells, Heat Pumps and Sorption Systems*, 203-207, 2010.11. |

24. |
N. Sakoda, K. Shindo, K. Motomura, Supriatno, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Measurement of PVT Property of Hydrogen at High Pressures up to 100 MPa and Development of a Virial Equation of State, *Proceedings of the 9th Asian Termophysical Properteis Conference*, paper number 109156, 2010.10. |

25. |
Y. Takata, N. Sakoda, K. Shinzato, M. Fujii, Measurement of Hydrogen Thermophysical Properties at Ultra High Pressures, *Proceedings of the 9th Asian Termophysical Properteis Conference*, paper number 109309, 2010.10. |

26. |
A. Widyaparaga, M. Kuwamoto, N. Sakoda, M. Kohno, Y. Takata, Theoretical Study of a Flexible Wiretype Joule Thomson Micro-refrigerator for Use in Cryosurgery, *8th International Conference on Nanochannels, Microchannels and Minichannels*, 2010.08. |

27. |
N. Sakoda, K. Shindo, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, PVT Measurements of High Pressure Gas by the Burnett Method, *Proceedings of the International Conference on Power Engineering 2009(ICOPE-09)*, Vol. 2, 265-270, 2009.11. |

28. |
N. Sakoda, K. Shindo, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, PVT Measurements of Hydrogen at High Pressures, *Abstracts of the 17th Symposium on Thermophysical Properties*, 370, 2009.06. |

29. |
Y. Takata, P. L. Woodfield, N. Sakoda, K. Shinzato, M. Fujii, Measurement of Hydrogen Thermophysical Properties at High Pressure, *The Eleventh UK National Heat Transfer Conference (UKHTC2009)*, 2009.06. |

30. |
N. Sakoda, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Development of PVT Measurement Apparatus and Preliminary Measurements for Hydrogen, *Book of Abstracts of 18th European Conference on Thermophysical Properties*, 197, 2008.08. |

31. |
Y. Takata, N. Sakoda, K. Shinzato, K. Fujii, M. Fujii, Research Project of Hydrogen Thermophysical Properties at Ultra High Pressure, *Proceedings of Sixth International Conference on Enhanced, Compact and Ultra-Compact Heat Exchangers: Science, Engineering and Technology*, 2007.09. |

32. |
N. Sakoda, E. Yusibani, P. L. Woodfield, K. Shinzato, M. Kohno, Y. Takata, M. Fujii, Review of Thermophysical Properties of Hydrogen and the Related Work of HYDROGENIUS, *Proceedings of the 8th Asian Thermophysical Properties Conference*, 141, 2007.08. |

33. |
N. Sakoda, A. Wachi, N. Masuda, M. Uematsu, PVT Measurements of Ammonia and Its Aqueous Mixtures in the Temperature Range from 350 K to 600 K at Pressures up to 200 MPa, *Abstracts of THERMO INTERNATIONAL 2006 (The 19th IUPAC International Conference on Chemical Thermodynamics)*, 523-524, 2006.07. |

34. |
D. Kume, N. Sakoda, M. Uematsu, An Equation of State for Thermodynamic Properties of Methanol, *Book of Abstracts, The 17th European Conference on Thermophysical Properties*, 292, 2005.09. |

35. |
N. Sakoda, M. Uematsu, Thermophysical Properties of the Binary Mixture of Methane and Hydrogen Sulfide, *Abstracts of Thermodynamics*, 50, 2005.04. |

36. |
N. Sakoda, M. Uematsu, A Thermodynamic Property Model for the Binary Mixture of Methane and Hydrogen Sulfide, *Abstract book, The 18th IUPAC International Conference on Chemical Thermodynamics*, 140, 2004.08. |

37. |
N. Sakoda, M. Uematsu, Thermodynamic Property Model for Binary Mixtures of Methane and Hydrogen Sulfide, *Abstracts of the 15th Symposium on Thermophysical Properties*, 20, 2003.06. |

38. |
K. Tanaka, N. Sakoda, M. Uematsu, Development of a Calorimeter for Measurements of Isobaric Heat Capacity for Fluids and Fluid Mixtures in a Wide Range of Temperatures and Pressures, *Book of Abstracts, 9th International Conference on Properties and Phase Equilibria for Product and Process Design*, 126, 2001.05. |