Triangular Bar Research Articles

はり柱の主筋の付着力に関する実験的研究

The bond strength of TRICON, high-strength deformed triangular bar made by Kobe Steel Work Ltd, is compared with that of high-strength deformed round bar and also that of high-strength round bar in beams and columns. The results of the test are as follows. 1) TRICON has the same properties of bond strength as high-strength deformed round bar. 2) In the test, both TRICON and deformed round bar are pulled out of the concrete specimens by gradually breaking them. 3) When the concretes are reinforced up to the limits (1.5d and more than 2.5cm) provided by the standard, the allowable shearing strength of the test specimens does't depend upon the bond strength of reinforcements but the shearing strength of concretes. 4) Round bars are pulled out with out cracking concretes. 5) The bond strength of round bars almost attained allowable bond unit stresses for long sustained loading. This result is considered to be significant.

Feeding Mechanism of Water-Bugs

THE suggestion put forward by Walton1 that the presence of small teeth and chitinous elevations in the pharynx of Micronecta indicates that this Hemipteran ingests and masticates particulate food material appears to be true for other families of the Cryptocerata. There exists in many, and probably all, species of Corixidae a type of feeding mechanism which does not seem to have been recorded. This takes the form of a modification of the cibarial suction pump2 in such a manner as to produce a pair of chitinous jaws having a structure and position strongly suggesting that they function as organs for the comminution of solid material. It is a mechanism more elaborate in form than that found in Micronecta. The whole ventral wall of the cibarial pump consists of a curved chitinous plate having a thickened posterior margin. The anterior border of this plate appears to be folded back and modified into a transverse triangular bar set with rows of minute tooth-like projections. Above this bar and articulating with it at its lateral ends lies a second chitinous bar formed by the thickened dorsal wall of the cibarium and similarly equipped with teeth or rugosities (Fig.1). The two bars have the appearance of a pair of grinding jaws, and although the musculature of the organ has not been studied in detail, enough has been noted to support this supposition.