Enhancement of Photothermal Conversion by TiN Nanoparticles-Embedded Black Paint and Applications in Solar Drying of Red Chilli.

This work explores a new application of titanium nitride nanoparticles (TiN NPs) as efficient photothermal materials in enhancing the greenhouse effect. We demonstrate that a simple greenhouse using TiN NPs-embedded black paint boasts several advantages in solar drying technology, which are indicated by the drying of red chilli. In particular, the greenhouse using TiN NPs significantly improves the drying efficiency, which reduces the mass of red chilli by approximately four times and results in dried chilli with a moisture content of 10% within two days. In addition, by conducting long experiments in various environments, we found that the relative humidity can have a predominant role over the temperature in the solar drying of red chilli and observed that the re-adsorption of moisture can take place during the drying process, which prolongs the drying time and reduces the quality of the dried products.

Methane and nitrous oxide emissions in the rice-shrimp rotation system of the Vietnamese Mekong Delta.

Rice-shrimp rotation systems are one of the widespread farming practices in the Vietnamese Mekong Delta coastal areas. However, greenhouse gas (GHG) emissions in the system have remained unclear. This study aimed to examine methane (CH4) and nitrous oxide (N2O) emissions from the system, including (i) land-based versus high-density polyethylene-lined (HDPE) nursery ponds and (ii) conventional versus improved grow-out ponds inoculated with effective microorganisms (EM) bioproducts. The results showed that CH4 flux in land-based and HDPE-lined nursery ponds were 1.04 and 0.25 mgCH4 m-2 h-1, respectively, while the N2O flux was 8.37 and 6.62 µgN2O m-2 h-1, respectively. Global warming potential (GWP) from land-based nursery ponds (18.3 g CO2eq m-2) was approximately 3 folds higher than that of the HDPE-lined nursery pond (6.1 g CO2eq m-2). Similarly, the mean CH4 and N2O fluxes were 15.84 mg CH4 m-2 h-1 and 7.17 µg N2O m-2 h-1 for the conventional ponds, and 10.51 mg CH4 m-2 h-1 and 7.72 µg N2O m-2 h-1 for the improved grow-out ponds. Conventional practices (2388 g CO2eq m-2) had a higher 1.5-fold GWP compared to the improved grow-out pond (1635 g CO2eq m-2). The continuation of the land-based nursery pond and conventional aquacultural farming practices increase CH4 emission and GWP, while applying HDPE-lined nursery ponds combined with improved grow-out ponds could be a promising approach for reducing GHG emissions in rice-shrimp rotation systems. This study recommends further works in the rice-shrimp rotation systems, including (i) an examination of the effects of remaining rice stubbles in the platform on the availability of TOC levels and GHG emissions and (ii) ameliorating dissolved oxygen (DO) concentration on the effectiveness of GHG emission reduction.