Examining disjointedness of dot patterns based on a three-stage serial processing model of symmetry cognition

Rotational and reflectional transformations were applied to dot patterns in a square grid generating cyclic (Cn) and dihedral (Dn) groups (n = 1, 2, 4). Judgments of disjointedness (the inverse of unifiedness) of 8-, 13- and 21-dot patterns were compared with poorness (the inverse of goodness) and complexity (the inverse of simplicity) judgments. Results found were (a) disjointedness and complexity of 8-dot D2 linear patterns decreased by an anisotropic spatial filter, (b) three cognitive judgments for the patterns other than the linear patterns monotonically decreased as a function of group order, (c) disjointedness of C2n and Dn (n = 1, 2) were indistinguishable and were processed in a former-stage of group theoretical model, and poorness and complexity were distinguished in C2n and Dn while being processed in a latter-stage, (d) complexity increased monotonically as the number of dots increased. While 13- and 21-dot patterns results were insignificant, disjointedness judgments were lowest in 8-dot patterns, and influence of poorness was ineffectual. We have proposed a three-stage serial processing model of symmetry cognition

Mechanical Pre-Compression System of the JT-60SA Central Solenoid

The mechanical loading technology has been developed for the pre-compression of central solenoid for the tokamak device of JT-60 super advanced (JT-60SA) being constructed in Japan. Four central solenoid modules were manufactured one by one, then 4 modules were stacked. The pre-compression were conducted to bind stacked 4 modules by support structure called tie-plate as a final process of the central solenoid manufacturing. The pre-compression jigs were designed by using the finite element analysis taking into account of plastic deformation of the jigs and the tie-plate. The pre-compression was performed using developedjigs.The hydraulic jacks and pumps were separately installed to the each tie-plate to control the pre-compress load individually. Since the pre-compress load changed by insulation creeping after initial loading, additional shims were inserted for the tie-plate with small load. Finally, pre-compress load of all tie-plate became within the target range. These results indicate that the pre-compression has been successfully completed using the developed jigs. In this paper, the design and analysis of the pre-compression jigs and the result of the pre-compression are reported

Design of JT-60SA Cryodistribution Components

JT-60SA is a fusion experiment tokamak device with supercon-ducting magnets to be built in Japan. As a unique feature of the JT-60SA cryodistribution system, the main cryogenic transfer line from the helium refrigerator directly inserts into the tokamak cryostat at 12.4 m height, and then it branches to 12 distribution units separately placed around the tokamak through headers in the cryostat. This configuration contributes to the maximization of plasma volume and installation flexibility for heating and measurement devices of plasma experiments but causes compli-cated cooling paths and severe conditions on a mechanical design due to the seismic event and the thermal contraction. In this work, we represent the system design of JT-60SA cryodistribution and several component designs in these severe conditions

A group theoretical model of symmetry cognition

We report on two experiments, published originally in Japanese, on judged goodness and simplicity of dot patterns with reflectional and rotational symmetries (with 1–4 reflection axes and repeats, respectively) under free-viewing tasks. We found that (a) both goodness and simplicity increase monotonously with the number of transformations under which a pattern is invariant; (b) stimulus outlines, such as squares and hexagons, affect both goodness and simplicity; and (c) factors such as contrast polarity and collinearity affect simplicity rather than goodness. The employed free-viewing tasks contrast with detection tasks involving short presentation times, and based on behavioural and neurophysiological evidence, we conclude that this transformational approach captures late rather than early aspects of visio-cognitive processing of visual regularities.status: publishe

Effect of SHe temperature on Cool-down Speed in JT-60SA CS module

The JT-60SA central solenoid (CS), which consists of four stacked modules, is cooled to an operating temperature of 4.5 K by supercritical helium (SHe). During cool-down from room temperature to 4.5 K, in order to avoid a damage on the coil, it is required to reduce thermal stress due to temperature difference in the coil. In the cool-down operation, the CS needs to control the maximum temperature difference in the longitudinal direction of the cable-in-conduit (CIC) conductor below 40 K. However, since that could damage the coil, correctly estimating the temperature distribution in the conductor is important for ensuring the cooldown operation is performed safely. In the present study, the JT- 60SA CS module was prepared and the inlet and outlet temperatures, as well as the SHe mass flow rate, were measured until the CS module was cooled to operating temperature, after which a CS module simulation was performed in order to determine the effect of the inlet temperature on the cool-down speed. From the simulation results, it was concluded that the average cool-down speed was 0.73 K/h and the CS module reached 80 K in approximately 8.3 days while maintaining the maximum temperature difference within 40 K. Furthermore, the temperature difference between the inlet and outlet was kept within 25 K in order to limit the thermal stress. Taken together, the results of our analyses provide fundamental data that can be used to evaluate the safe cool-down operation of the coil and thus protect the coil systems.Applied Superconductivity Conference 2020 (ASC2020