RESUMO
Although natural emulsifiers often have many drawbacks when used alone, their emulsifying ability and stability can usually be improved unexpectedly when used in combination. In this study, monodisperse emulsions stabilized by combining two natural protein emulsifiers, i.e., whey protein isolate (WPI) and sodium caseinate (SC), in different proportions were prepared using microchannel (MC) emulsification. The influences of temperature, pH, ionic strength, and storage time on the microstructure and stability of the emulsions were examined. Analysis of the microstructure and droplet size distribution revealed that the WPI-, SC-, and mixed protein-stabilized emulsions exhibited uniform droplet distribution. The droplet size and ξ-potential of the MC emulsions stabilized by mixed protein emulsifiers were higher than those of the emulsions stabilized by WPI or SC separately. The emulsions stabilized by the two types of proteins and mixed emulsifiers had better stability under high salt concentrations than the synthetic emulsifier Tween 20. WPI-SC-stabilized emulsions were more resistant to high temperatures (70-90°C) and exhibited excellent stabilization than those stabilized by WPI and SC, which was attributed to the more sufficient coverage provided by the two types of protein emulsifier layers and better protein adsorption at the oil-water interface. These results indicate that WPI-SC is a potential stabilizer for MC emulsion requirements. This study provides a basis for the formulation of monodisperse and stable natural emulsion systems.
RESUMO
Understanding the relationships between ecosystem services (ES) and their underlying socioecological drivers is essential for forming the efficient management decisions of ecosystems. We use a large watershed area as a case-study to analyze trade-offs/synergies and bundles of ESs and identify the associated socioecological variables (SEVs). This study assessed the supply of 7 ES indicators, namely, three provisioning services (crop production, livestock production, and industrial production), three regulating services (water conservation, soil conservation, and carbon sequestration), and one cultural service (recreation), across 65 municipalities in the Yellow River Basin (YRB) in China. We analyzed the paired trade-offs/synergies using Spearman's coefficient and identified the ES bundles (ESBs) by applying principal component analysis and K-means clustering. Subsequently, we detected the SEVs that affect the ES supply using the geo-detector model and characterized the associations between ESBs and socioecological clusters according to the spatial overlap. The results demonstrated that the synergies between ESs substantially exceeded the trade-offs, among which the strongest synergies were between the crop production and the livestock production, and both responded strongly to the cropland and the population density. Trade-offs were identified between provisioning services and soil conservation. Municipalities were grouped into three ESBs in the YRB. The ESB, which was dominated by provisioning ESs, was associated with areas where cropland, precipitation and socioeconomic conditions were all important, and the regulation of ESB was linked to regions with distinct ecological characteristics. We also identified an ESB that was dominated by carbon sequestration, as determined by extensive grassland and bare land. The land use/land cover strongly affected the characteristics of the ESBs. The findings can be used by land managers to identify areas in which ESs are dominant, to determine the associations of these compositions of the ESs with SEVs, and to support the formulation of optimal ES management in large-scale basins.
RESUMO
Using Theil index and spatial autocorrelation analysis methods, the characteristics, regional disparity and spatial pattern evolution of carbon emission intensity from energy consumption were analyzed on national, regional and provincial level from 1999 to 2007 in China. The results indicate that: (1) total energy carbon emission in China has increased from 0.91Gt in 1999 to 1.83Gt in 2007, while carbon emission intensity has decreased from 0.83 t x (10(4) yuan) (-1) to 0.79 t x (10(4) yuan) (-1); (2) carbon emission intensity of eight major economic blocks showed the trend of three-level differentiation, with that of northeast regions, the middle reaches of Yellow River regions and northwest regions above 1.0 t x (10(4) yuan)(-1); northern coastal regions, the middle reaches of Yangtze River regions and southwest regions 0.7-1.0 t x (10(4) yuan) (-1); eastern and northern regions 0.32-0.51 t x (10(4) yuan) (-1); (3) Theil index analysis indicates that the within-region carbon emission intensities were similar, and the expanding total disparity of carbon emission intensity was primarily due to between-region inequalities. (4) spatial autocorrelation analysis shows that Global Moran's I has increased from 0.19 to 0.25, indicating that there were positive spatial correlations among provincial regions in China, and regions of similar carbon emission intensity agglomerated in space. The "cold spot" areas of carbon emission intensity were relatively stable, while the "hot spot" areas has gradually shifted from northwest regions to the middle reaches of Yellow River regions and northeast regions. (5) spatial disparity of carbon emission intensity is closely related to factors such as regional resources endowment, economic development, industrial structure and energy utilization efficiency. The study of regional disparity and spatial autocorrelation provides insight into spatial heterogeneity and spatial pattern evolution of carbon emission intensity in China, and also provides references for the development of differential regional objectives of carbon emission reduction and related regulation policies.
