In this paper, the wakes behind a square cylinder were simulated using two kinds of different turbulence models for the eddy viscosity concept such as the zero- and the one-equation model in which the former is the mixing length model and the latter is the k-equation model. For comparison between numerical and analytical solutions, we employed three skill assessments: the correlation coefficient(r) for the similarity of the wake shape, the error of maximum velocity difference(EMVD) for the accuracy of wake velocity and the ratio of drag coefficient(RDC) for the pressure distribution around the structure. On the basis of the numerical results, the feasibility of each model for wake simulation was discussed and a suitable value for the empirical constant was suggested in these turbulence models. The zero-equation model, known as the simplest turbulence model, overestimated the EMVD and its absolute mean error(AME) for r, EMVD and RDC was ranging from 20.3 % to 56.3 % for all test. But the AME by the one-equation model was ranging from 3.4 % to 19.9 %. The predicted values of the one-equation model substantially agreed with the analytical solutions at the empirical mixing length scale L=0.6b1/2 with the AME of 3.4 %. Therefore it was concluded that the one-equation model was suitable for the wake simulation behind a square cylinder when the empirical constant for eddy viscosity would be properly chosen.

Platycodon grandiflorum (Bell flower) is an important plant that has traditionally been used as herbal medicine for the treatment of cough, phlegm, sore throats, lung abscesses, chest pains, dysuria, and dysentery. The present study was initiated to investigate the feasibility of inducing shoot and root organogenesis in cultured explants of P. grandiflorum in a range of culture media and through use of various plant growth regulators (PGRs). The plantlets (Stem containing one node) were isolated and cultured on different concentrations of Murashige and Skoog (MS) medium supplemented with PGRs. We found that proliferation and elongation of shoots and roots could be achieved on ¼ MS for P. grandiflorum with wild and green petals and on ⅛ MS for P. grandiflorum with double petals. The highest levels of development and elongation of adventitious shoots and roots were observed when petal explants were cultured on ¼ MS (pH 3.8) supplemented with 5% sucrose. Increasing the agar concentration reduced shoot growth and rooting potential; nevertheless, the highest number of shoots and roots was observed on 0.6% agar. In the case of growth regulators, ¼ MS supplemented with 1 mg L-1 6-benzylaminopurine (BA) was found to be best for shooting, although higher concentrations of BA tended to reduce shoot and root elongation. The highest number of shoots was achieved on 0.5 mg ․ L-1 thidiazuron (TDZ) from double petal explants grown on ⅛ MS. However, root and shoot elongation were found to decrease when TDZ concentrations were increased. Low concentrations of kinetin, naphthalene acetic acid, indole acetic acid, and 3-indole butyric acid induced shoot and root proliferation and elongation. Taken together, our study showed that low concentrations of PGRs induced the greatest root formation and elongation, showing that the optimal concentration of PGRs for shoot proliferation was species-dependent.

Characteristics related to grain quality and starch viscosity were investigated in three independent japonica transgenicrice lines expressing a Protox gene from Bacillus subtilis and compared to the control. In this study, we found that there were nosigni