Graphene nanoplatelets were successfully prepared from graphite powder by simple and scalable thermal shock combined with ball milling methods. The formation of the graphene nanoplatelets were observed by field-emission scanning electron microscopes and Brunauer–Emmett–Teller methods with the much smaller number of layers and the considerable increase of specific surface area in comparison to the initial expanded graphite material. The other characterizations such as Fourier transform infrared spectroscopy and X-ray powder diffraction methods of graphene nanoplatelets showed unchanged structure. These graphene nanoplatelets were combined with aluminum trihydroxide and zinc borate to prepare flame-retardant polycarbonate plastic and chlorine-sulfonated polyethylene rubber. The prepared composites showed the improvement of flame resistance properties with V0 level according to the UL-94 test method, and the limiting oxygen index value was higher than 27.

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Ag/SiO 2 colloidal nanocomposites (NCs) were synthesised by the chemical reduction of silver ions on a silica surface; NaBH 4 was used as a reducing agent, while chitosan served as a stabiliser. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) results of Ag/SiO 2 showed a high-density distribution of silver nanoparticles on the silica surface. The influence of pH, ionic concentrations on the stability of Ag/SiO 2 colloidal NCs was investigated. Ag/SiO 2 colloidal NCs were stable in a wide range of pH values (3-10) and the presence of cations (Mg 2+ 25 mM, Ca 2+ 15 mM, Fe 2+ 1 mM, Fe 3+ 0.8 mM). Furthermore, the antimicrobial activity of Ag/SiO 2 colloidal NCs against Ralstonia solanacearum 15 (R. solanacearum 15), Bipolaris oryzae (B. oryzae) was evaluated. The minimum inhibitory concentration (MIC) of Ag/SiO 2 colloidal NCs for R. solanacearum 15 was 10 ppm, two times lower than that of silver nanoparticles (AgNPs) at 20 ppm, which were prepared by the same route. The inhibitory rate of Ag/SiO 2 colloidal NCs against B. oryzae was 99.3% higher than the inhibitory rate of AgNPs 80.4% at the same Ag concentration of 32 ppm. Therefore, Ag/SiO 2 colloidal NCs with high antimicrobial activity and stability in wide range pH and ionic strength are a promising pesticide in agriculture.

The land's natural resources are invaluable and a requisite for the existence and development of humans and other organisms on Earth. In recent years, under the strong impact of new directions in economic and social development, the demand for land has been increasing. The percentage of land used for residential living, transportation, irrigation and infrastructure tends to increase, while the share of agricultural land is continuously decreasing. Consequently, the allocation and efficient use of land is one of the most important concerns in order to enable sustainable development, environmental protection and ecology. Therefore, research to determine the volatility and changing trends in land use is necessary. This study uses remote sensing and GIS technology, combined with the Markov Chain to determine variation and forecast the changes in land use in the Y Yen district of the Nam Dinh province of Vietnam. This will create a basis for helping land managers grasp the situation in local land use management.