A gas-liquid two-phase flow problem in turbo-pumps has lately become of interest to pump designers and engineers. The final goal in tackling this problem is to develop a pump which does not lose its pumping function even in a two-phase flow with high void fraction. In this report the transition from a bubbly flow to gas accumulation in the centrifugal pump impeller with inlet void fraction increasing is discussed after showing qualitatively that the gas accumlation in the impeller causes the pump head degradation. Next, effects of pump geometries on the head degradation are made clear from the review of past experimental results. Finally, a conceptual view for designing this kind of pump is described in the present situation of two-phase flow pump research.

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Since the Pneumatic Capsule Pipeline System (PCPS) for the limestone transportation started its operation in 1983, PCPS has not had another opportunity of its application. Although it offers an automatic system which is both user-and environment-friendly, its high cost was thought to outweigh its merits. However, the need to find a way of cutting down on accidents, noise and dust in the construction industry became increasingly urgent. This led to the use of the PCPS in the construction of the Hokuriku Shinkansen's Akima Tunnel as the transportation sub system for the Extruded Concrete Lining Method (ECL Method), a fully automatic tunneling method capable of sovling the above mentioned problems. This PCPS transports ready-mixed concrete from the tunnel mouth to the tunnel head and, in the opposite direction, earth from the tunnel head to the disposal area which is 3 km distant from the tunnel mouth. It can transport 100m³/H of earth by launching a capsule train consisting of three (3) capsule vehicles every 2 minutes. It uses rectangular steel reinforced concrete pipe with an internal width of 900mm. The station inside the tunnel has to catch up with the excavating machine, which will progress about 7km in two (2) years. It is divided into three (3) units. The first unit discharges ready-mixed concrete from capsule vehicles and loads capsule trains with earth. The second goes back and forth between the first and the last unit and exchanges capsule trains with each other. The last, which is usually connected to the pipeline, receives and launches capsule trains. Traveling distance of the second unit increases as the excavating machine progresses. At certain intervals the second unit is disconnected from the pipeline and new concrete pipes are inserted between them. Since solving some teething problems the tunneling has progressed more than 1 km. PCPS applied tunneling is expected to spread widely in order to keep the construction environment safe and clean.

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Winslow's Effect is defined as an essentially instateneous reversible change in apparent viscosity when a fluid is subjected to an externally applied electric field. ER (Electro-Rheological) fluids that show an extreme increase in viscosity could be employed as new functional materials and are target for competitive development worldwide. Fundamentally, ER fluids are to drive clutches and hydraulic valves which can control torque and the pressure respectively only by application of a high voltage. In one recent application which received keen attention ER fluids were used in an engine mount with an active vibration control function. However, ER fluids should not be seen simply as a means of controlling uncomfortable ribration. They can be expected to have a vast range of applications as elements for highly functional servo control systems. Here, specific characteristics of ER fluids are reviewed, and new applications developed for servo systems are introduced. Regarding the effectiveness of ER fluids, the greatly improved capacity for control that can result from their use in servo systems is demonstrated by their application in the case of a robot with a pneumatic manipulation system.

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A slug flow model containing an expression for pressure loss in a pneumatic conveyance system for dredged materials is established with regard to Bingham fluid conveyance in a long-distance, wide-diameter pipeline. This slug flow model divides one slug into three parts; front, main and tail, and calculates pressure loss for each part. Pressure loss at the front derives from momentum loss caused by the effect of an accelerating liquid layer on the slug flow's fluid velocity. That at the main part derives from friction resistances caused by viscousness and normal stress. That at the tail can be disregarded because current gravity occurs at this part. Previous studies of air-liquid two-phase flows have focused mainly on liquid of low viscosity in short, narrow-diameter pipelines. Applying the previous slug model to the Bingham fluid slug-air two-phase flow, pressure loss cannot be estimated accurately because it is expressed only by friction resistance between pipe and slug. In this study, pressure loss was measured for dredged materials in a pipline 1000m long and 350mm in diameter. Pressure loss estimates obtained from the slug flow model agreed closely with the experimental findings.

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