PVC Plate Research Articles

落網の網型模型に対する魚群行動の水そう実験

In order to compare the performance of trap nets, water tank experiments of fish behavior to the model nets constructed by PVC plate were conducted, using bitterling Rhodeus ocellatus ocellatus as an experimental fish and a video behavior analyzer system for observing and analysing the fish behavior. Six different types of trap nets as the model net were examined; two mouth trap net with two bags, two mouth trap net with a left bag, two mouth trap net with a right bag, single mouth trap net with two bags, single mouth trap net with a left bag and single mouth trap net with a right bag. For the fish school comming from the left hand side of the leader net, the rate of right turn behavior just after entering the net was extremely high; 89% for the two mouth trap nets and 76% for the single mouth trap nets. The rate of remaining, which was employed as an index of the catching performance, showed the maximum in the right bag net and the minimum in the left bag net for both the two mouth trap nets and the single mouth trap net. The results seem to support an empirical rule that the bag net should be set to the same side as the leader net in the single mouth trap net.

On the Interrelationship of Various Mechanical Properties for Rigid PVC Plates

In order to find out the general view of mechanical properties for rigid PVC plates as a whole, the measured values of various kinds of mechanical properties have been investigated with respect to their mutual relations about ten kinds of plates. The results obtained are summarized as follows:(1) There exists a close relationship between the results of tensile tests and those of impact tests. The plate which shows more sudden necking phenomenon at its arising in the tensile test, has lower impact strength.(2) There are roughly linear relationships between any two of the Vickers, the Brinell, the Rockwell and the Shore-rebound hardnesses. The values of HV/σ1 (HV: Vickers hardness, σ1: tensile strength, i.e. yield strength) take roughly a constant value, i.e. 2.3.(3) The rigid PVC plate which shows higher modulus of elasticity, has higher yield strength (tensile strength), higher hardness, smaller elongation and lower impact strength. There are roughly linear relationships between any two of the measured values of above mentioned mechanical properties.

Correlation between Impact Strengths Measured on the Basis of Various Standards for Rigid PVC Plates

The Charpy method and the Izod method are usually applied to test of impact strength of rigid PVC plate. There are some differences between various standards on shapes and dimension of the Charpy impact test specimens. Ten kinds of rigid PVC plates have been tested according to the JIS, the ISO and the ASTM Charpy impact testing methods, and also to the ASTM Izod impact testing method. The results obtained are summarized as follows:(1) JIS Charpy impact strengths (JIS·akC) of the test plates take the values from 2.3 to 8.4kg-cm/cm2.(2) ISO Charpy impact strengths (ISO·akC) of the test plates, except an extruded one, take roughly a constant value i.e. 2.5kg-cm/cm2.(3) ASTM Charpy impact strengths and ASTM Izod impact strengths show similar characteristics. Their characteristics are both divided into two groups, i.e. ductile group (JIS·akC>5kg-cm/cm2) and brittle group (JIS·akC<5kg-cm/cm2). The characteristics of ductile and brittle groups are similar to those of JIS·akC and ISO·akC respectively.(4) The above mentioned phenomenon is caused mainly by the difference of notch depth.(5) There are approximately linear relationships between various impact strengths except a few values. The regression lines shown in Table IV can be used for conversion of an impact strength into another one.