53 research outputs found

    Microorganisms Relating to Color Development in Cured Meats

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    Article信州大学農学部紀要 11(2): 271-280(1974)departmental bulletin pape

    Advancements in Gel Science—A Special Issue in the Memory of Toyoichi Tanaka

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    It is a great pleasure for us to present a collection of recent papers that were submitted to the special issue of Gels, Advancements in Gel Science—A Special Issue in Memory of Toyoichi Tanaka [...

    Transport Phenomena in Gel

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    Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed

    Structure and Frictional Properties of Colloid Gel

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    Polymer gels are known to be opaque when the preparation conditions, such as the reaction temperature and the composition, are changed. The increase of the opaqueness of the gel suggests strongly the change of network structure. Here, we are going to review the recent studies on the structure and the frictional study of the opaque poly(acrylamide) gel. The results indicate that the opaque poly(acrylamide) gel consists of the fractal aggregate of the colloidal particles of sub-micrometer in size. The density of the colloid particle is calculated from the structural parameters and is found to be of the order of about 1 g/cm3. The results indicate that the main chain component and the cross-linker is densely cross-linked into the particle. The frictional property of poly(acrylamide) gel is analyzed in terms of the structural parameters of the gel. It is found that the frictional property of the opaque gel is well explained in terms of the structural parameters of the opaque gel

    Phase Transition of Gels—A Review of Toyoich Tanaka’s Research

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    In 70’s, the extensive studies about the gel science has begun with the discovery of the volume phase transition of gel at the physics department of Massachusetts Institute of Technology. After the discovery of the volume phase transition of gel, the phenomenon was extensively studied and advanced by the discoverer, the late Professor Toyoichi Tanaka, who deceased on 20 May 2000 in the halfway of his research. In this paper, we would like to review his research to clarify his deep insight into the science of gels

    Advancements in Gel Science—A Special Issue in Memory of Toyoichi Tanaka

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    A gel is a state of matter that consists of a three-dimensional cross-linked polymer network and a large amount of solvent. Because of their structural characteristics, gels play important roles in science and technology. The science of gels has attracted much attention since the discovery of the volume phase transition by Professor Toyoichi Tanala at MIT in 1978. MDPI planned to publish a Special Issue in Gels to celebrate the 40th anniversary of this discovery, which received submissions of 13 original papers and one review from various areas of science. We believe that readers will find this Special Issue informative as to the recent advancements of gel research and the broad background of gel science

    Transport Phenomena in Gel

    No full text
    Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed

    Dynamics of Spinodal Decomposition in a Ternary Gelling System

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    The phase diagram and phase transitions of the ternary system of gelatin, water and poly(ethylene glycol) oligomers were studied as a function of the weight fraction of gelatin and the weight fraction and molecular weight of poly(ethylene glycol) oligomers. It was found that both phase separation and the sol-gel transition occur in this ternary system. The relative position of the phase separation line and the sol-gel transition line depends on the weight fraction and the molecular weight of the poly(ethylene glycol) oligomer that coexists in the solution. All aspects of the phase diagram are sensitive to the molecular weight of the poly(ethylene glycol) oligomer. Since the phase separation line crosses the sol-gel transition line in the phase space that is created by the temperature and the weight fraction of gelatin, the phase space is typically divided into four regions, where each region corresponds to a definite phase. The transitions between mutual phases were studied using the light-scattering technique
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