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To solve the problem of the proportional design of cement concrete prepared by using manufactured sand instead of river sand, a new method of manufactured sand concrete mix design was proposed with the dense packing of coarse and fine aggregate. Compared with the original sieving method, the stone powder in the manufactured sand can be regarded as cementitious materials for slurry. With the proposed mix design method, there is no need to separate from the manufactured sand. This dense packing method considers the actual situation that both the manufactured sand and coarse aggregate are mechanically prepared, and all the aggregates can be unified in proportion. The composition ratio of aggregate with particle size greater than 0.075 mm is designed by the maximum density theory, and the rest of the part (below 0.075 mm) is treated as a cementitious material. As a parameter of the maximum density theory, the Fuller index of 0.45 was verified when the calculation values agreed well with the test results. With the proposed mix ratio design method, the different grades C30, C40, and C50 of manufactured sand concrete were designed. Furthermore, the properties such as workability and mechanical properties for the designed manufactured sand concrete were investigated to determine the applicability of the proposed mix design method. The test results show that the workability, uniformity, and strength of the manufactured sand concrete were better than the original mix ratio design method, which verifies the operability and reasonableness of the proposed mix ratio design method. [ABSTRACT FROM AUTHOR]

Samples from two outcrop sections, MGS1 and DGS1 of Milanggouwan and Dishaogouwan in the Salawusu River Basin, were studied in terms of grain size using end-member model. Results show that: 1) MGS1 layer particles are more concentrated, better sorting, and smaller skewness and kurtosis values than those of DGS1. Whereas in the upper part of the DGS1 section, the grain size of the paleodune is coarser, with better sorting and sharper peak, comparing with the lower lacustrine sediments. 2) Three end-member components, EM1 (end-member 1), EM2 (end-member 2) and EM3 (end-member 3), which reflect sedimentary dynamic characteristics, are extracted by end-member analysis. The EM1 indicates the hydrodynamic force with great variation, EM2 indicates transporting force by flowing water and EM3 indicates the depositional environment closely related to the wind activity. 3) According to the accumulation processes of MGS1 and DGS1 strata, a total of four climate periods can be identified, namely early warming period, Holocene peak period, fluctuating transition to cold period and unstable cooling period. Moreover, EM1 of MGS1 and DGS1 is basically consistent with both the sea surface temperature (SST) in the western tropical Pacific and global temperature trends during the Holocene, suggesting that the environmental fluctuations recorded by MGS1 and DGS1 can be correlated with each other. [ABSTRACT FROM AUTHOR]

In the past, during development processes, major ecological and environmental problems have occurred in the agro-pastoral ecotone of China, which have had a strong impact on regional sustainable development. As such, analyzing the evolution of the regional ecosystem service value (ESV) and predicting the futural spatio-temporal evolution under different development scenarios will provide a scientific basis for further sustainable development. This research analyzed the regional land use and land cover change (LUCC) from 2000 to 2020, adopted the Mark-PLUS model to construct different scenarios (prioritizing grassland development, PDG; prioritizing cropland development, PCD; business as usual, BAU), and simulated the future LUCC. The driving factors influencing each land use type were revealed using the PLUS model. Based on the LUCC data, the spatio-temporal distribution of the regional ESV was calculated via the ESV equivalent factor method, including four primary services (supply service, adjustment service, support service, and cultural service) and eleven secondary services (water resource supply, maintaining nutrient circulation, raw material production, aesthetic landscape, food production, environmental purification, soil conservation, maintaining biodiversity, gas regulation, climate regulation, and hydrologic regulation). The results showed that the total ESV increased first and then declined from 2000 to 2020, reaching the highest value of CNY 8207.99 million in 2005. In the different future scenarios, the ESV shows a trend of PGD (CNY 8338.79 million) > BAU (CNY 8194.82 million) > PCD (CNY 8131.10 million). The global Moran index also follows this distribution. Additionally, precipitation (18%), NDVI (16%), and DEM (16%) are the most important factors in the regional LUCC. The spatial agglomeration characteristics of ESV were revealed using the global Moran's index and local indicators of spatial auto-correlation, which show a high coordination degree between the high–high cluster areas and water areas. These results point out the key points in the next step of ecological restoration projects and help with achieving the sustainable development goals more effectively. [ABSTRACT FROM AUTHOR]

The nearshore sand bar-sheet sedimentary system of the K-Successions sandstones of the Zhujiang Formation (23.8-16.5 Ma) in H21 Area of Huizhou Depression, Pearl River Mouth Basin has been identified in this research according to lithological characteristics, lithofacies, sedimentary sequence and seismic attributes. Seven lithofacies were recognized: fine-grained massive sandstone (Sm), fine-grained trough cross-bedded sandstone (St), fine-grained planar-bedded sandstone (Sp), fine-grained ripple cross-bedded sandstone (Sr), fine grained horizontally-bedded sandstone (Sh), laminated claystone with interbedded siltstone (Fl) and massive mudstone (Fm). Three sedimentary microfacies were further divided: sand bar, sand sheet and interbar. With the progradation and retrogradation process influenced by sea level changing, delta evolution of K-Successions sandstones in H21 area of Huizhou Depression can be divided into four stages: the early stage of the transgressive systems tract, A/S>1; the medium stage of the transgressive systems tract, A/S>1; the end stage of transgressive systems tract; the stage of the highstand systems tract, A/S