Netsu Sokutei

Phase Transition of Organic Molecular Crystal Observed by Thermal Diffusivity

Naoko Miyamoto, Junko Morikawa, Toshimasa Hashimoto

2003 Volume 30 Issue 3 Pages 98-105
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.98

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Fourier transform temperature wave analysis (FT-TWA) is proposed as a method to observe the phase transition of organic molecular crystals. By analyzing the harmonics of temperature wave, it enables a simultaneous measurement of thermal diffusivity as a function of frequency and temperature. This technique was applied to a temperature range including the solid-solid or the solid-liquid phase transition of n-alkane, 1-alkanol, 1-alkanoic acid and its esters. Thermal diffusivity of n-alkanes showed a rapid fall-off on each phase transition and the odd-even effect of carbon number was observed. The frequency dependence of thermal diffusivity just below the melting temperature was observed only for n-alkanes and 1-alkanol, which showed a clear solid-solid phase transition with a conventional method. The effect of terminal group on thermal diffusivity was also examined.

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Development of a Twin Type Conduction Calorimeter with a Vacuum Chamber for Radioactivity Measurements

Seikichi Iwamoto, Seiichi Hagiwara, Tsuguo Genka

2003 Volume 30 Issue 3 Pages 106-110
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.106

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A twin type conduction calorimeter having a vacuum chamber was developed for high sensitive measurements of radioactivity of radionuclides with lower noise level and smaller baseline drift. The object of present experiment was to investigate the effect of low pressure (around 0.67Pa) atmosphere on the thermal noise and baseline drift of the calorimeter output. The results showed lower thermal noise, 0.015μV p-p, (0.09μW), smaller baseline drift, 0.015μV p-p, (0.135μW), and higher sensitivity, 0.17μVμW¹ in comparison with a conventional calorimeter operated in the atmospheric pressure.
Small amount of thermal power evolved from the radioactive sample of carbon-14 (Ba¹⁴Co₃) sealed in a glass vial was non-destructively measured using this calorimeter.
The radioactivity of C-14 was determined from the measured thermal output of 3.56μW±1.58% (standard deviation) and its overall uncertainty was estimated by considering various factors. Consequently the result was found to be 450MBq (12mCi)±4.9% (in 99.7% credibility limit). The result suggested more than 10 times improvement in sensitivity of radioactivity measurement was attained.

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Thermal Properties of the Liquid Silk for Silkworms

Domestic and Mutant Domestic and Wild Silkworm

Toshihisa Tanaka, Yoshiko Magoshi, Jun Magoshi

2003 Volume 30 Issue 3 Pages 111-115
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.111

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The thermal properties of liquid silk obtained from the domesticated silkworm (Bombyx mori), the mutant domesticated silkworm (Sericin cocoon silkworm, Nd-s), and four wild silkworms (Samia cynthia ricini, Dictyoploca japonica, Antheraea pernyi and Antheraea yamamai) were investigated by differential scanning calorimetry (DSC).
The weak endothermic peak in the DSC curves for the liquid silk of the domestic silkworm corresponded to the breaking of hydrogen bonds in the α-form of fibroin. The process of crystallization of the liquid silk differed between domestic and wild silkworm. The starting temperature of transition for the liquid silk of the domestic silkworm was calculated.

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Enthalpies of Sublimation after a Century of Measurement

A View as Seen through the Eyes of a Collector

James S. Chickos

2003 Volume 30 Issue 3 Pages 116-124
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.116

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Measurements of sublimation enthalpy are reviewed from an empirical perspective. Some of the reasons responsible for the lack of agreement between measurements are discussed and some general advice is given to prospective users of the sublimation enthalpy data.

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Solubility Parameter Prediction of Polymers by Thermal Analysis

Nobuyuki Tanaka

2003 Volume 30 Issue 3 Pages 125-130
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.125

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Solubility parameter of polymers is defined as the square root of the cohesive energy per cm³. For crystalline polymers, the cohesive energy is approximated by the sum of the heat of fusion, the heat of transition due to ordered parts in the amorphous regions, and the heat of glass transition. In this review, the methods to obtain these thermodynamic quantities by thermal analysis and as the background, the glass transition and the melting for polymers were discussed.

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Changes of the Structure and Physical Properties of Polysaccharide Aqueous Solutions by Annealing

Masato Takahashi, Tokihiro Takizawa, Tatsuko Hatakeyama, Hyoe Hatakeya ...

2003 Volume 30 Issue 3 Pages 131-136
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.131

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Changes of the structure and physical properties of polysaccharide aqueous solutions by annealing are discussed based on the experimental results of viscoelastic measurements and thermal analysis. In the annealing process of polysaccharide aqueous solutions, dynamic modulus increased as functions of annealing time and temperature suggesting the change of molecular association. It was found that the solution annealed in the sol state tends to form hydrogels. Furthermore it was shown that the amount of non-freezing water in the system is closely related to the molecular association of polysaccharides and gelation characteristics. In this dtudy, the structural change of polysaccharides, such as xanthan gum and hyaluronan, in the annealing process is discussed based on the experimental results.

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Excess Molar Enthalpy Measurements of Multicomponent Alcohol-Ether Mixtures and their Representation in Terms of an Association Model

Mohammad Mainul Hossain Bhuiyan, Kazuhiro Tamura

2003 Volume 30 Issue 3 Pages 137-145
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.137

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Our recent studies on the measurement of excess molar enthalpies of alcohol-ether multicomponent solutions are reviewed in terms of a UNIQUAC associated-solution model. In this model, we have taken into account the self-association like alcohols, multicross-association of unlike alcohols and solvation between alcohols and ethers. The UNIQUAC associated-solution model, which includes association constants, solvation constants and optimally fitted binary parameters obtained solely from the pertinent binary correlation, can predict the ternary excess molar enthalpies with an excellent accuracy.

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Development of a Piezo-Optic Cell for Optical Microscopy

Yoji Maeda

2003 Volume 30 Issue 3 Pages 146-147
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.146

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A Novel Technique and Mechanism of Protein Crstal Growth

An Approach from Crystal Engineering

H. Adachi, K. Takano

2003 Volume 30 Issue 3 Pages 148-149
Published: June 30, 2003
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.30.148

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