When a rider slides on virgin surfaces without lubrication, wear of the metals is affected by the shape and size of the test pieces. In this paper, the mechanism of wear, caused by movement of the wear particles is discussed.
It is found that some wear particles, transfered from the test piece to the virgin surface come back again to the original surface and there is an equilibrium state in which the mass of the back transfered particles is equal to the wear particles, transfered from the original, surface. This study shows that metal wear W is expressed by the following equation.
W=h₀pL₀∫∫e^-k₁xdx dy
where
p: constant pressure
L₀: sliding distance
x: length of test piece
y: width of test piece
h₀: transfer constant
k₁: back transfer constant

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In the previous paper, the slip line construction of the plastic field produced by restricted contact tools was discussed.
Based upon the characteristics of the slip line field, a quantitative treatment for variation of coefficient of friction on rake face with an artificial restriction of tool-chip contact length is proposed in this paper, in comparison with experimental results. The experimental results appear to support the treatment.

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By the use of the trially made ultra-micro scratching hardness tester, the relation 'between the scratching loads and the deformations has been clarified on the optically polished silicon. Hardness numbers having been obtained, along the depths from the polished surfaces of germanium and silicon the worked layers are discussed in view of the hardness variations. The results obtained are as follows:
(1) The work softening exists in silicon to a depth of 700 Å, while the indication of softening is seen in germanium at a depth of less than 200 Å.
(2) The constant hardness numbers are shown at a depth of 10, 000-15, 000 A for both crystals, which is very close to that obtained from the etching rate curves.
(3) The softening phenomenon is caused by the temperature rises due to surface friction. According to the simplified model, the temperatures reach near the softening points for both crystals.

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Recently, the pilot plants has been used in the chemical engineering experiments for checking the process in the large plants. As the liquid conveyance plays an important part in the chemical industries, the necessity of mini-flow in the pilot plants has been increased.
The customary constant flow devices have some problems in their detecter and controller, and it is difficult to produce the small rate of flow under 300 cm³/min.
The author has produced the constant flow of less than 10 cm³/min in good accuracy by controlling the pressure difference between the inlet side and outlet side of the gear pump within a certain allowable limit. This device is entirely different from the customary con-stant flow devices in principle, and it is simple in mechanism and stable in movement.

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