In this research, the mechanical properties and structural studies of the geopolymer nanocomposite of metakaolin-red mud/carbon nanotubes were investigated. The geopolymer was designed by using metakaolin and red mud as aluminosilicate sources. Red mud replaced between 10 to 30% of the metakaolin. The mass ratio of the solid material and activator liquid was optimized in 1.5:1. Afterward, 1, 2, and 3 wt. % multi-wall carbon nanotubes (MWCNTs) were dispersed in a polycarboxylate-based superplasticizer and were added to the geopolymer, which was mixed homogeneously. Geopolymer nanocomposites were characterized by XRD, FTIR, SEM, compressive and flexural strength measurements. The results indicated that the compressive and flexural strengths of the samples increased with curing time. The addition of red mud decreased the compressive and flexural strength of the geopolymer samples due to less reactivity and presence of a non-reactive impurity in red mud. By adding 2% MWCNTs, the compressive and flexural strengths increased to 37.05% and 36.06%, respectively, owing to the crack-bridging mechanism and filling of the cavities and porosity. FTIR spectra demonstrated the growth of the asymmetric stretching vibrations of T–O–Si (T: Si or Al) at approximately 995.85-1083.55 cm-1, confirming the realization of the geopolymerization process in the structure.

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The seedless barberry, 'Bidaneh,' is one of the most important cultivated small fruits in Iran. This cultivar is propagated only by suckers, and so, the establishment of large-scale orchards is not possible in a short period of time. During this research, different grafting methods were evaluated on the grafting success rate of 'Bidaneh' on wild types of barberry. More than 1000 grafts including cleft grafting (with hard shoots and green/semi-hard shoots), omega grafting, T-budding, and chip budding (at mid-spring and late summer) methods were performed for two consecutive years (2018 and 2019). The results showed that the grafting methods have significant effects on the percentage of callus formation and graft success (P < .01). The chip budding method resulted in the maximum callus formation (36.7%), and graft success (30%). The rate of callus formation and graft success in the cleft grafting with semi-hard shoots was 2% and 18%, respectively. No callus formation and graft success were found in the cleft in hard stem and omega grafting methods. The graft success was zero in T-budding, despite of 18.33% callus formation. The results revealed the success of grafting of 'Bidaneh' on wild barberry species for the first time. However, increasing the graft success rate requires further research.

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