For the compression process with deformation of a particle, a new compression equation has been derived by combining Rumpf's equation and Hiramatsu's equation. The Rempf's equation can estimate the relationship between compressive stress and the force acting on a contact point between particles. Hiramatsu's equation gives the relationship between the compressive force and the tensile strength of a particle. The newly derived compression equation contains a tensile strength term for each particle that the bed consists of. When this equation is applied to the compression process, the tensile strength of a particle can be estimated, but the strain of a single particle during compressing should previously be estimated or measured.
It was shown that the Kawakita's equation was derived from the new compression equation with some assumptions. A constant, 1/b, in the Kawakita's equation has been considered to be correlated with the tensile strength of a particle.
It was shown in this investigation that the tensile strength of a particle was proportional to the constant, 1/b, under the condition that the strain was constant during the compression process.

抄録全体を表示

The solitonic self-organization phenomena in a granular medium appear when an external force exceeds some threshold value so that the onset of the ordered solitonic states is regarded as energy transition similar to that observed in complex nonlinear cooperative systems. Experimental investigations were made on solitary wave propagation, on the energy transfer through nonlinearity, on the evolution of the ordering parameter and on the effect of external noise on the solitonic mechanism.
The phase plane of the ordered dynamic states is found to contain an attracting set on which the motion of the system is aperiodic, and which describes a complex dynamics. Information processing in the granular medium is characterized by parallel processing of the non-Von Neumann's type in selforganized systems (by cooperative actions).

抄録全体を表示

A size-selective procedure has been developed in order to obtain samples of asbestos fibers of different lengths for use in biological experiments. Short Chrysotile fibers less than 5μm in length are widely suspected to be less carcinogenic than longer fibers. The bulk sample of U. I. C. C. standard asbestos (Chrysotile B) was aerosolized using -component fluidized bed. It was then separated in the dry state by wire ens (200 mesh and 635 mesh) and a virtual impactor with a cut-off point of 2μm.
0.1g (sufficient weght for in-vitro tests) of a short-fiber fraction that passed through the wire screens and then onto the fine side of the virtual impactor, and 1.5g of a medium fraction that passed through the 200 mesh screen but did not pass through the 635 mesh screen, were obtained from about 20g of raw material. The length distribution of the short fiber fraction was 81% of fibers less than 5μm long and 96 percent of fibers less than 10μm long. X-ray diffraction analysis revealed that the crystallinity of the separated chrysotile was not markedly changed. The present dry and mild separation process that was developed thus successfully avoids any artificial change in the physicochemical properties of asbestos fibers.

抄録全体を表示

The variation in particle size, specific surface area, S_p, and dispersibility in a polar liquid were measured by the continuous grinding of polypropylene (PP) with a non-ionic surfactant (NP7.5) or a titanate coupling agent (KR9S). With an amount of additive of 1mmol per kg PP, S_p increased by 20-30%, and the energy efficiency of comminution increased by a factor of three to four. The surface of PP beeame hydrophilic by adding 60mmol NP 7.5 per kg PP during the comminution, as revealed from the comparison of apparent partice size in water, ethanol and cyclohexane. Although the crystallographical degradation was enhanced by the additives, no change in the molecular weight distribution was observed even after intensive grinding with additives. Tribochemical sorption on the surface of PP was, therefore, not detected.

抄録全体を表示