Agriculture and forestry play important roles in Vietnam, particularly as they contribute to the creation of food, conservation of forest resources, and improvement of soil fertility. Therefore, understanding the performances of relevant enterprises in this field contributes to the sustainable development of this country's agroforestry industry. This research proposes a hybrid model, which includes a grey model (GM) and a Malmquist productivity index (MPI), to assess the performances of Vietnamese agroforestry enterprises over several time periods. After collecting the data of selected input and output variables for 10 Vietnam agroforestry enterprises in the period of 2011-2014, GM is used to forecast the future values of these input and output variables for the 10 agroforestry enterprises in 2015 and 2016. Following the results of GM, the MPI is used to measure the performance of these enterprises. The MPI scores showed some enterprises will become more efficient, while others will become less efficient. The proposed model gives past-present-future insights in order for decision-makers to sustain agroforestry development in Vietnam. This hybrid approach can be applied to performance analysis of other industries as well.

Abstract:Scientists have found that nanomaterials possess many outstanding features in their tiny grain structure compared to other common materials. Titanium at the nano-grain scale shows many novel characteristics which demonstrate suitability for use in surgical implants. In general, equal channel angular pressing (ECAP) is the most popular and simple process to produce nano-titanium. However, ECAP is time-consuming, power-wasting, and insufficiently produces the ultrafine grain structure. Therefore, the objective of this research is to propose a new method to improve the ECAP's performances to reach the ultrafine grain structure, and also to save production costs, based on the innovation theory of Teoriya Resheniya Izobreatatelskih Zadatch (TRIZ). Research results show that the process time is reduced by 80%, and 94% of the energy is saved. Moreover, the grain size of the diameter for nano-titanium can be reduced from 160 nanometers (nm) to 80 nm. The results are a 50% reduction of diameter and a 75% improvement of volume. At the same time, the method creates a refined grain size and good mechanical properties in the nano-titanium. The proposed method can be applied to produce any nanomaterial as well as biomaterials.

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