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Volume 18 (1991)
- Issue 4 Pages 193-
- Issue 3 Pages 127-
- Issue 2 Pages 53-
- Issue 1 Pages 3-
Volume 18, Issue 3
Displaying 1-9 of 9 articles from this issue
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Mineo Watase, Katsuyoshi Nishinari1991 Volume 18 Issue 3 Pages 127-137
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSEffects of ethylene glycol (EG) on the thermal and rheological properties of aqueous agarose gels were examined in order to clarify the relation between the structure of gels and the functional properties. The endothermic peak accompanying gel-to-sol transition in heating DSC curves shifted to lower temperatures with increasing mole fraction of EG. The storage Young's modulus E' and the endothermic enthalpy ΔH of agarose gels as a function of EG mole fraction showed a maximum at a certain EG mole fraction. It was suggested that the region of the ordered structure increased with increasing EG below a certain EG mole fraction, and decreased with increasing EG above that mole fraction. Those phenomena were discussed on the basis of a reel-chain model and a zipper model approach. Values of E' and ΔH may increase with increasing the number of junction zones or molecular zippers, which don't affect so much on the gel-to-sol transition temperature.View full abstractDownload PDF (1226K) -
Reiji Tanaka, Minori Adachi1991 Volume 18 Issue 3 Pages 138-149
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSApparent molar volumes Vφ, apparent molar heat capacities Cp, φ, and relative apparent molar enthalpies Lφ of the mixed solute {di-2-ethylhexyl sodium sulfosuccinate (Aerosol OT, or AOT)+r·H2O} in cyclohexane were determined over the molality range of 0.0002 to 1mol kg-1 at 298.15K. The heats of dilution were measured by using a newly constructed flow-calorimeter. The excess enthalpies for the systems (benzene+cyclohexane) and (chlorobenzene+toluene) at 298.15K were also measured to test the operating technique for the calorimeter. In the system without adding water (r=0) the enthalpy of dilution changes from endotherm to exotherm at about 0.2mol kg-1, and the change in Cp, φ with molality is monotonous. In the systems with r≥5 a sharp peak appears at m=0.001mol kg-1 in Cp, φ and the enthalpy of dilution increases very sharply at m < 0.01mol kg-1. We concluded that the intermolecular interaction of AOT in cyclohexane is moderate, and no micelles are formed. In the systems with r≥5 a transition occurs at m=0.001mol kg-1 and W/O microemultion is formed.View full abstractDownload PDF (1384K) -
II. Excess Molar Isobaric Heat CapacityH. Ogawa, H. Mitsuo, H. Inoue, K. Tamura, S. Murakami1991 Volume 18 Issue 3 Pages 150-156
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSWe have measured excess molar isobaric heat capacities for dimethylacetamide (DMAC)+alkane mixtures at 298.15K. The result indicates a W-shaped concentration dependence as predicted from the result of extremely high endothermic excess enthalpies for these mixtures.
The W-shaped dependence arises from a positive non-randomness contribution in excess heat capacity. DMAC molecules have large dipole moment and dipolar interaction acts between them as the intermolecular interaction in the pure state. By mixing with hydrocarbon, this interaction is broken and the more energy is required to weaken the dipolar interaction in the solution state than in the pure state.View full abstractDownload PDF (807K) -
Hiroko Yokobayarhi1991 Volume 18 Issue 3 Pages 157-163
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThermal dehydration of lanthanide hexacyanocobaltate (III) hydrates Ln[Co(CN)6]·nH2O where Ln=La∼Lu except Pm, n=5 for La and Ce, n=4 for Pr∼Lu was investigated by TG-DTA, X-ray powder diffraction analysis and IR spectroscopy. The dehydration of the complexes occurred in multiple steps. The coordinated water were lost first, followed by the dehydration of lattice waters.
The features of the dehydration modes, which were very caracteristic of Ln, was explained by a proper combination of two factors (changes in size and effective charge of Ln) coming from the lanthanide contraction.View full abstractDownload PDF (718K) -
Kiyoshi Terayama, Takayoshi Ishiguro1991 Volume 18 Issue 3 Pages 164-169
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThe present study is concerned with the pre-reduction process of some manganese ores using CO, H2 and C as a reducing agent, respectively. The multi-techniques of TG, DTA and DTGA (Differential Thermal Gas Analysis) were used for more hight precision measurements. MnO2 or Mn2O3 phase in manganese ore is continuously converted into lower oxides under a suitable condition of temperature and oxygen partial pressures. MnO phase is obtained easily in the reduction process up to about 1273K. The reduction of MnFe2O4 which yields MnO-FeO phase also investigated by the examination of X-ray diffraction.View full abstractDownload PDF (821K) -
Yuji Haikawa, Yasuo Saruyama1991 Volume 18 Issue 3 Pages 170-173
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDynamic heat capacity of at-polypropylene has been measured around the glass transition temperature. The dynamic heat capacity vs temperature curve shifted to higher temperature as the frequency of the periodic heating increased. The activation energy was estimated as 77kcal/mol from the Arrhenius plot. It was found by comparing the results from the thick sample and the thin sample that the thermal conductivity does not exhibit anomalous behavior around the glass transition temperature.View full abstractDownload PDF (735K) -
Toshihiro Tanaka, Takamichi Iida1991 Volume 18 Issue 3 Pages 174-183
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSCHEMSAGE, which was recently developed at Technische Hochschule Aachen in Germany, is a calculation software with a users-friendly interface for chemical equilibria. This software, based on the SOLGASMIX Gibbs energy minimizer, was designed to perform the calculation of thermodynamic functions, heterogeneous phase equilibria, and steady-state conditions for the simulation of simple multistage reactors. In this paper, the structure and characteristics of CHEMSAGE are introduced with some examples on the application of it for some metallurgical problems.View full abstractDownload PDF (1186K) -
T. Maruyama, I. Niiya1991 Volume 18 Issue 3 Pages 184-187
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDownload PDF (501K) -
T. Nomaki, H. Sasaki, F. Shigemitsu1991 Volume 18 Issue 3 Pages 188-190
Published: July 30, 1991
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDownload PDF (319K)
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