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Abstract Models that accurately estimate maximum crop biomass to obtain a reliable forecast of yield are useful in crop improvement programs and aiding establishment of government policies, including those addressing issues of food security. Here, we present a new sigmoidal growth model (NSG) and compare its performance with the beta sigmoidal growth model (BSG) for capturing the growth trajectories of eight crop species. Results indicated that both the NSG and the BSG fitted all the growth datasets well (R 2 > 0.98). However, the NSG performed better than the BSG based on the calculated value of Akaike’s information criterion (AIC). The NSG provided a consistent estimate for when maximum biomass occurred; this suggests that the parameters of the BSG may have less biological importance as compared to those in the NSG. In summary, the new sigmoidal growth model is superior to the beta sigmoidal growth model, which can be applied to capture the growth trajectory of various plant species regardless of the initial biomass values at the beginning of a growth period. Findings of this study will be helpful to understand the growth trajectory of different plant species regardless of their initial biomass values at the beginning of a growth period.

Low nano-SiO2 loaded nylon 6 (PA6) nanocomposites were readily produced via in situ polymerization. The effect of surface-modified functional groups of nano-SiO2 on the interfacial structure and properties of nylon 6/SiO2 nanocomposites were studied, which indicated that the surfaces of the two kinds of nano-SiO2, namely RNS-A and DNS-3, contained amino groups and alkyl chains, respec‐ tively. Furthermore, as-prepared nanocomposites were characterized by means of transmission electron microsco‐ py (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the PA6 chains were attached to the surface of nano-SiO2 by the modes of physical adsorption and chemical bonding. Nano-SiO2 was found to uniformly disperse inside nanocomposites with RNS-A and DNS-3, thereby increasing the superior strength and toughness of nanocomposites in comparison to the pure PA6. Of particular interest was the enhancement of the thermal stability of nanocomposites by adding RNS- A; meanwhile, DNS-3 had little effect on thermal stability. This was the possibly explained by the enhancement of thermal stability owing to the cross-linked reaction. Moreover, the reaction system exhibited gelatine following the addition of RNS-A up to 1.5wt%.

Low nano-SiO2 loaded nylon 6 (PA6) nanocomposites were readily produced via in situ polymerization. The effect of surface-modified functional groups of nano-SiO2 on the interfacial structure and properties of nylon 6/SiO2 nanocomposites were studied, which indicated that the surfaces of the two kinds of nano-SiO2, namely RNS-A and DNS-3, contained amino groups and alkyl chains, respectively. Furthermore, as-prepared nanocomposites were characterized by means of transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the PA6 chains were attached to the surface of nano-SiO2 by the modes of physical adsorption and chemical bonding. Nano-SiO2 was found to uniformly disperse inside nanocomposites with RNS-A and DNS-3, thereby increasing the superior strength and toughness of nanocomposites in comparison to the pure PA6. Of particular interest was the enhancement of the thermal stability of nanocomposites by adding RNSA; meanwhile, DNS-3 had little effect on thermal stability. This was the possibly explained by the enhancement of thermal stability owing to the cross-linked reaction. Moreover, the reaction system exhibited gelatine following the addition of RNS-A up to 1.5wt%. [ABSTRACT FROM AUTHOR]