Thermal-mechanical optimization of folded core sandwich panels for thermal protection systems of space vehicles

The integrated thermal protection system (ITPS) is a complicated system that addresses both mechanical and thermal considerations. An M-pattern folded core sandwich panel packedwith low-density insulation material provides inherently lowmass for a potential ITPS panel. Herein, we identify the most influential geometric parameters and establish a viable, computationally efficient optimization procedure. Variables considered for optimization are geometric dimensions of the ITPS, while temperature and deflection are taken as constraints. A one-dimensional (1D) thermal model based on a modified form of the rule of mixtures was established, while a three-dimensional (3D) model was adopted for linear static analyses. Parametric models were generated to facilitate a design of experiment (DOE) study, and approximate models using radial basis functions were obtained to carry out the optimization process. Sensitivity studies were first conducted to investigate the effect of geometric parameters on the ITPS responses. Then optimizations were performed for both thermal and thermal-mechanical constraints. The results show that the simplified 1D thermal model is able to predict temperature through the ITPS thickness satisfactorily. The combined optimization strategy evidently improves the computational efficiency of the design process showing it can be used for initial design of folded core ITPS

Anthocyanin Accumulation and Molecular Analysis of Correlated Genes in Purple Kohlrabi (Brassica oleracea var. <i>gongylodes</i> L.)

Kohlrabi (Brassica oleracea var. <i>gongylodes</i> L.) is an important dietary vegetable cultivated and consumed widely for the round swollen stem. Purple kohlrabi shows abundant anthocyanin accumulation in the leaf and swollen stem. Here, different kinds of anthocyanins were separated and identified from the purple kohlrabi cultivar (Kolibri) by high-performance liquid chromatography–electrospray ionization tandem mass spectrometry. In order to study the molecular mechanism of anthocyanin biosynthesis in purple kohlrabi, the expression of anthocyanin biosynthetic genes and regulatory genes in purple kohlrabi and a green cultivar (Winner) was examined by quantitative PCR. In comparison with the colorless parts in the two cultivars, most of the anthocyanin biosynthetic genes and two transcription factors were drastically upregulated in the purple tissues. To study the effects of light shed on the anthocyanin accumulation of kohlrabi, total anthocyanin contents and transcripts of associated genes were analyzed in sprouts of both cultivars grown under light and dark conditions

Accumulation and Molecular Regulation of Anthocyanin in Purple Tumorous Stem Mustard (Brassica juncea var. <i>tumida</i> Tsen et Lee)

Tumorous stem mustard (Brassica juncea var. <i>tumida</i> Tsen et Lee) is an economically and nutritionally important dietary vegetable in Asian countries. Purple tumorous stem mustard contains inflated tumorous stem and abundant anthocyanin accumulation in leaves. Here, 20 anthocyanins were separated and identified from the purple tumorous stem mustard by high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS/MS). In order to investigate the regulatory anthocyanin production in purple tumorous stem mustard, the expression of anthocyanin biosynthetic and regulatory genes in leaves from purple and green cultivars were examined. Regulatory gene <i>BjTT8</i> and all biosynthetic genes were dramatically upregulated in the purple variety. Moreover, the transcript level of <i>BjTT8</i> and all structural genes, except <i>BjPAL</i>, were all significantly higher in light-treated sprouts than in the dark. These results indicate that transcriptional activation of <i>BjTT8</i> is associated with upregulation of most anthocyanin biosynthetic genes, to produce anthocyanins in purple tumorous stem mustard