Under the stimulus of the rheological experimental results which were reported in 1964 [M. Yusa and A. M. Gaudin, Am. Ceram. Soc. Bull., 43, 402], a new solid-liquid separation process which is referred to as “pelleting flocculation process” has been developed and industrialized [M. Yusa, H. Suzuki, and S. Tanaka, J. Am. Water Works Assoc., 67, 397, 1975]. The term “flocculation” is usually defined as the “transport process”, in which dispersed particles are brought together by thermal motion and/or fluid motion [W. J. Weber, Jr., Physicochemical Processes for Water Quality Control, Wiley-Interscience, pp.92~93, 1972]. The definition of flocculation seems not applicable to the pelleting flocculation. From a new angle, flocculation has been defined as the phenomenon, in which dispersed particles are transported by thermal motion and/or fluid motion, and some structure is induced among the particles that were brought together by the transport process. The structure induced among the particles is usually referred to as “flocculated structure”. It somehow has not come under our notice so far that the “flocculated structure” concept is essential fully to understand the phenomenon of flocculation. Subsequently, it has been proposed to establish a new branch of applied science to be known as “flocculation engineering”, defined as “a branch of science to originate and develop the technique of making the flocculated structure that fits the purpose of any process, through some suitable method of controlled the conditions of flocculation”. Furthermore, the above-mentioned data reported in 1964 and the relationship between the pelleting flocculation and the traditional theories of flocculation have been discussed, proving the great possibilities of flocculation engineering. Clearly, the pelleting flocculation process forms a part of flocculation engineering. Finally, the “flocculated structure model” has been proposed, which consists of 1) random floating structure, 2) random capillary II structure, 3) random capillary I structure, and 4) random packed structure. Simultaneously, the schematic representation of the model has been presented. The model may become the basic starting point of flocculation engineering.
The pressure transmitting characteristics of dispersed systems of air-cured tobacco powder (Matsukawa) and water was examined by measuring the pressure distribution throughout the sample consolidated in a cylinder under various loading pressures. The rate of pressure transmitted from the axial direction of the cylinder to the radial direction increased with increasing static pressure of loading, hence with increasing degree of consolidation, and it reached a limiting value lower than unity, indicating that the system remained pseudoplastic. The limiting rate increased with increasing content of water, e.g. 0.89 for a 36.2%-water system and 0.93 for a 72.4%-water. The flow behavior of the system was also studied with a ram-type extruder. The apparent viscosity ηa decreased with increasing rate of shear and with decreasing concentration of the tobacco powder. The effect was of comparable degree with that previously obtained for a dispersed system of flue-cured tobacco powder (Bright Yellow) and water (this Journal, 5, 8 (1977)). However, ηa of the present system was larger by about 8 times than that of the Bright Yellow system if comparison was made at the same condition of water content and shear rate.
The rheological behavior of lubricating greases was studied in the temperature range from room temperature to about 250°C by using a concentric cylinder-type viscometer, which is more convenient for measurements at high temperatures than the widely used ASTM viscometer of capillary type. The following results were obtained: (1) Lubricating greases exhibited the Ostwald flow; that is, the viscosity was independent of the rate of shear in both regions of extremely low shear rates and extremely high shear rates. (2) The rate dependence of viscosity was observed within a rather narrow shear rate range at high temperatures. (3) The relative viscosity of each soap-thickened grease started to decrease as the temperature was increased beyond a certain value. This behavior was attributable mainly to the rupture of structural linkage of thickener micells or to the rupture of micells themselves, judging from the observation of electron micrographs.
The low-shear rotational viscometer of the Zimm-Crothers type was modified so that successive dilution of a given solution can be made in the viscometer, as is the case with the capillary viscometer of the Ubbelohde type. This modification simplifies the process of determining the intrinsic viscosity of polymer solution at zero rate of shear. In the instrument constructed, the rotor is driven by rotating an electrically induced magnetic field whose strength can be changed continuously with the supply of variable electric current, and the range of shear rates from about 0.1 to 10 sec-1 can be studied. The data taken on two polystyrene samples (Mv=2.28×105 and 3.35×107) in benzene and one poly-n-hexyl-isocyanate sample (Mv=4.0×106) in carbon tetrachloride are illustrated to show the potential of the instrument.