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The effect of dispersant structures for dispersing single‐walled carbon nanotubes (SWCNTs) is investigated. The monomer 3‐hexylthiophene is used as the starting material for the development of a series of oligomers that are used to disperse SWCNTs in an organic solvent. The series is obtained by varying the number of head groups, the regioregularity of head groups, and the head‐to‐tail ratios of the hexyl group in the oligomers. The SWCNT solutions are characterized with UV‐vis–near‐IR spectroscopy and transmission electron microscopy. An increase in the number of head groups improves the dispersity of SWCNTs, and a regioregular oligomer plays an important role in dispersing SWCNTs. Furthermore, Raman spectroscopy and X‐ray photoelectron spectroscopy shows that the sulfur atom head groups enhance interactions between the thiophenes and the SWCNT walls. The analysis demonstrated that a well‐designed thiophene oligomer could afford well‐dispersed SWCNT solutions with long‐term dispersion stability, even with an extremely low dispersant concentration (weight ratio of CNTs/dispersant is one and the dispersant concentration is 0.1 g L–1).

Contact damage and crack patterns in two types of whiteware layered structure were investigated as a function of firing temperature, for single and multi-cyclic loading in Hertzian contact tests. In the layered structures fired at 1200°C, the damage mode and crack patterns were similar for different coating layer compositions, showing cone-like cracks at the coating layer and additional, upward extending transverse cracks at the internal interface, with cone-like cracks dominant. The damage was enhanced on increasing indentation load P and number of cycles n, with quasi-plastic deformation dominant. System failure occurred at higher indentation loads and number of cycles (n = 104at P = 500 N), following quasi-plastic deformation in the substrate and fracture in the coating layer. In the case of 1300°C firing, only cone-like cracks were initiated at the coating layer independent of the indentation load P in single cyclic loading. Two layered structures with different compositions in the coating layer showed no difference at a lower indentation load, P = 200 N, until n = 105and at a higher indentation load, P = 500 N, until n = 104in multi-cyclic loading. However, these structures showed a different damage mode at the higher indentation load and number of cycles, n = 105at P = 500 N. The dominant damage mode in the layered structure prepared at 1200°C was quasi-plasticity in the substrate, and at 1300°C was fracture in the coating layer, depending on the indentation load P and the number of cycles n.

This paper is concerned with the application of the Properties A and B associated with the incidence matrix to the analysis of Partially Balanced Designs having Binary Number Association Scheme (BNAS) or Balanced Factorial Experiments (BFE). We present a practical method of intra-and inter-block analysis of Partially Balanced Block Designs (PBBD) having BNAS. All group divisible association scheme designs, rectangular association scheme designs, hierarchical group divisible block designs, and direct product designs are BNAS PBB designs. The method presented in this paper will unify and simplify the calculations for the above various designs when compared with presently available procedures. Also, we extend the method to the PAB type rectangular designs. The various computational steps in the statistical analysis are presented with numerical examples.

Without Abstract:

The following relations have been demonstrated in this paper: an incomplete block design with property A in the Kurkjian-Zelen sense, is a balanced factorial experiment in the Shah sense which in turn is a partially balanced incomplete block design having a "binary number association scheme" and conversely; likewise, a rectangular design which has property A in columns and property B in rows in the Zelen-Federer sense, is a balanced factorial rectangular experiment which in turn is a partially balanced rectangular design, and conversely. The establishment of these relations is useful in constructing block and row-column designs which are partially balanced and in constructing fractional replicates which are balanced.