Effect of temperature on the flow properties of suspensions

Fine powder of CaCO₃ was dispersed in H₂O, ethylene, glycol (EG), and 50% aqueous solution of polyethylene glycol (PEG). In all cases, the apparent viscosity, η, of the suspensions decreased with temperature. The results are discussed on the basis of the energy dissipation theory. The total energy dissipation of flow, E_T(=η_aD²), per cm³ per sec was divided into two terms, i.e., E_p due to the interaction of flow units (flocs) and E_v, the viscous energy. E_v plays a dominant role when the viscosity of the medium, η_o, is large (e.g., for EG), whereas E_p is responsible for the overall flow behavior for the system with small η_o (e.g., for H₂O). From the analysis of E_p with respect to the rate of shear, D, and the effective floc concentration, a parameter m₂ was obtained, which is independent of D and of solid concentration, and serves as a measure of the extent of energy dissipation due to the interaction between flocs.     

A decomposition algorithm for solving certain classes of production-transportation problems with concave production cost

This paper addresses a method for solving two classes of production-transportation problems with concave production cost. By exploiting a special network structure both problems are reduced to a kind of resource allocation problem. It is shown that the resultant problem can be solved by using dynamic programming in time polynomial in the number of supply and demand points and the total demand.The author was partially supported by Grand-in-Aid for Scientific Research of the Ministry of Education, Science and Culture, Grant No. (C)05650061.     

Growth Processes due to Reactions in Swellable Cellular Matrixes

In matrix reactions in swellable cellular matrixes, the solids formed are oriented in space and arranged in the form of cells in strong three-dimensional growth processes. Open-cell, flexible, elastic polyurethanes have a particularly good matrix action. The principle is of general validity, and can be realized with a wide variety of matrixes and reaction types. The dimensional changes, which are always symmetrical, are largely determined by the chemical constitution of the matrix, segment structure, degree of crosslinking, and solvation and hydration behavior. One-component reactions having high rates give sigmoid growth curves and exhibit parallels with growth curves of plant cell walls containing cellulose.     

Die nichteuklidische Zyklographie und ebene Inversionsgeometrie (Geometrie vonLaguerre,Lie undMöbius) II

Ohne Zusammenfassung     

Rheological behavior of powder in a rotational viscometer

Summary The bahavior of granular materials in theMac Michael type viscometer was studied. The deflection angle of the bob decreased with the increase of the rate of rotation of the cup in the cases of these materials contrary to those of liquids. The powder bed in the gap of the viscometer is divided into twp cylindrical parts, the inner one with flowing layers of particles and the other moving with the cup as a bulk. The existence of these two parts is considered responsible for the extraordinary behavior of powder in the viscometer. The coefficient of kinetic friction of powder layers was obtained by applyingBenarie's analysis to our results.     

Liposomes possess drastic capabilities for topological transformation

Morphological and topological changes of biological membranes play essential roles in cellular activities. It has been thought that these transformations are made possible through interactions with proteins. However, direct observation of giant liposomes by optical dark-field microscopy reveals that the lipid bilayer itself possesses the ability to undergo topological transformation.     

Self‐aggregation of Synthetic Zinc Chlorophyll Derivatives Possessing 31‐Hydroxy or Methoxy Group and 131‐Mono‐ or Dicyanomethylene Moiety in Nonpolar Organic Solvents as Models of Chlorosomal Bacteriochlorophyll‐d Aggregates

Methyl 13¹‐(di)cyanomethylene‐pyropheophorbides were synthesized by Knoevenagel reactions of the corresponding 13¹‐oxo‐chlorins prepared from modifying chlorophyll‐a with malononitrile or cyanoacetic acid. Alternatively, methyl 13¹‐cyanomethylene‐pyropheophorbides were produced by Wittig reactions of 13¹‐oxo‐chlorins with Ph₃P=CHCN. Self‐aggregation of zinc complexes of the semi‐synthetic chlorophyll derivatives possessing a hydroxy or methoxy group at the 3¹‐position was examined in 1%(v/v) tetrahydrofuran or dichloromethane and hexane by electronic absorption and circular dichroism spectroscopy. Although intermolecular hydrogen‐bonding between the 3¹‐hydroxy and 13¹‐oxo groups of bacteriochlorophylls‐c/d/e/f was essential for their self‐aggregation in natural light‐harvesting antenna systems (=chlorosomes), zinc 3¹‐hydroxy‐13¹‐di/monocyanomethylene‐chlorins self‐aggregated in the less/lesser polar organic solvents to form chlorosome‐like large oligomers in spite of lacking the 13¹‐oxo moiety as the hydrogen‐bonding acceptor. Zinc 3¹‐methoxy‐13¹‐dicyanomethylene‐chlorin gave similar self‐aggregates regardless of lack of both the 3¹‐hydroxy and 13¹‐oxo groups. The present self‐aggregation was ascribable to stronger coordination of the 3¹‐oxygen atom to the central zinc than the conventional systems, where the electron‐withdrawing cyano group(s) increased the coordinative ability of the central zinc through the chlorin π‐system.     

Mössbauer Spectroscopic Characterization of Iron Species in Sliding Mud

Chemical states of Fe in the sliding mud and host rocks of landslide Kitayama and Tsuchikura were determined by ⁵⁷Fe Mössbauer spectroscopy. The composition of Fe species in the sliding mud is different from that in the debris and bedrock. The sliding muds contain more Fe(II); specifically the existence of pyrite indicates a stronger reducing condition in the sliding plane. Total Fe also varied along with Fe speciation. These data show that the sliding mud is formed under reducing condition. Iron speciation might be a useful means to estimate sliding mud generation and landslide progressing.

     

Studies on cerebral protective agents. II. Novel 4-arylpyrimidine derivatives with anti-anoxic and anti-lipid peroxidation activities. (2).

In a search for new cerebral protective agents with anti-anoxic (AA) and anti-lipid peroxidation (ALP) activities, a series of 4-arylpyrimidines, bearing an amino moiety in the C-5 position of the pyrimidine nucleus, was synthesized and tested for AA and ALP activities. Among them, 6-methyl-5-(4-methylpiperazin-1-ylcarbonyl)-4-(3-nitrophenyl )-2-phenylpyrimidin e (41, FK360) was most effective on both assays and on arachidonate-induced cerebral edema in rats. Structure-activity relationships in regard to AA activity of this series of compounds are also discussed.