Quantitative Estimation of Soil-Ground Water Storage Utilization during the Crop Growing Season in Arid Regions with Shallow Water Table Depth

Water storage in unsaturated and saturated zones during the crop non-growing season is one of the important supplementary water resources to meet crop water requirements in arid areas with shallow water table depth. It is necessary to analyze utilization of the soil-ground water storage during the crop growing season and its attribution to irrigation during the non-growing season. To facilitate the analysis, a new method based on measurements of soil moisture content and water table depth is developed. The measurements used in this study include (1) 15-year data of soil moisture content within a depth of 1 m from the land surface and water table depth measured in Jiefangzha, including its four subareas and (2) 4-year data of the same kind in Yonglian, located in arid northern China. The soil-ground water storage utilization is calculated as the difference of water storage between the beginning and end of the crop growing season in the whole computational soil profile. The results of average soil-ground water storage utilization in Jiefangzha and its four subareas and Yonglian are 121 mm, 126 mm, 113 mm, 124 mm, 185 mm and 117 mm, and the corresponding average utilization efficiencies in the non-growing season are 32.2%, 32.5%, 31.5%, 31.6%, 57.3% and 47.6%, respectively. Further, the water table fluctuation method was used to estimate the variation in water storage. The coefficients of soil-ground water storage utilization, soil-ground water storage utilization below 1 m soil depth and ground water utilization are defined, and their average values are 0.271, 0.111 and 0.026 in Jiefangzha, respectively. Then, the contribution of soil-ground water storage utilization to actual evapotranspiration is evaluated, which are over 23.5% in Jiefangzha and Yonglian. These results indicate that the soil-ground water storage plays an important role in the ecological environment in arid areas with shallow water table depth

Prior-Driven NeRF: Prior Guided Rendering

Neural radiation field (NeRF)-based novel view synthesis methods are gaining popularity. NeRF can generate more detailed and realistic images than traditional methods. Conventional NeRF reconstruction of a room scene requires at least several hundred images as input data and generates several spatial sampling points, placing a tremendous burden on the training and prediction process with respect to memory and computational time. To address these problems, we propose a prior-driven NeRF model that only accepts sparse views as input data and reduces a significant number of non-functional sampling points to improve training and prediction efficiency and achieve fast high-quality rendering. First, this study uses depth priors to guide sampling, and only a few sampling points near the controllable range of the depth prior are used as input data, which reduces the memory occupation and improves the efficiency of training and prediction. Second, this study encodes depth priors as distance weights into the model and guides the model to quickly fit the object surface. Finally, a novel approach combining the traditional mesh rendering method (TMRM) and the NeRF volume rendering method was used to further improve the rendering efficiency. Experimental results demonstrated that our method had significant advantages in the case of sparse input views (11 per room) and few sampling points (8 points per ray)

Input, stocks and output flows of urban residential building system in Beijing city, China from 1949 to 2008

Urban residential buildings are formed, maintained and reformed by different external material and energy flows, and their behaviors of input, accumulation and output are characterized by their architectural factors and modes of use that usually determine the consumption of material and energy of a building at its overall life cycle.In this research, we took Beijing city, a rapid developing city as a case study, and examined material flows of urban residential building system based on a survey of typical residential buildings in the urban areas of Beijing city. The quantitative analysis were made to describe the input, transformation/accumulation, and output of building materials from the year 1949 to 2008, and a comparative analysis was done to identify the differences of material uses among the buildings with different architectural structures as masonry-concrete, and steel-concrete.During the period from 1949 to 2008, there were six main materials of cement, sand, gravel, steel, bricks and timber used in urban residential building system in Beijing. The total amount of material imported into the system was 5.1 x 10(8) t, among which the accumulated amount was 4.7 x 10(8) t, an accumulation rate of 92.5%, and the total of building wastes reached 3.9 x 10(7) t. Among the buildings with two architectural structures, the total amount of material use for buildings with steel-concrete structure was larger than masonry-concrete. It was found that the buildings with steel-concrete structure experienced a rapid increase since the year 1979 in Beijing. As a result of rapid urban development, the large-scale reformation and demolishment of urban old buildings also led to a rapid growth of the amount of building wastes. And the building wastes generated in the process of reformation and demolition began to exceed that produced in the process of new buildings construction. The amount of building wastes generated from 2004 to 2008 accounted for 52.2% of the total that generated from 1949 to 2008.From this research, the rapid development of Beijing's residential building system in the past 60 years became a big ecological pressure for urban sustainable building development. It is important to change the traditional model of urban construction, and develop some sustainable or ecologically friendly construction technologies to enhance the capacity of recycling and reuse of residential building wastes for realizing a sustainable urban building construction and management in Beijing. (C) 2010 Elsevier B.V. All rights reserved

Cube-like Cu2MoS4 photocatalysts for visible light-driven degradation of methyl orange

Cube-like Cu2MoS4 nanoparticles with low-index facets and high crystallinity were fabricated via a hydrothermal method. The as-obtained nanocubes with an average size of 40-60 nm are composed of stacking-Cu2MoS4 layers separated by a weak Van der Waals gap of 0.5 nm. A strong absorption at visible light region is observed in the nanocube aqueous solution, indicating its optical-band gap of 1.78 eV. The photocatalytic measurements reveal that the nanocubes can thoroughly induce the degradation of methyl orange under visible light irradiation with good structural stability. Our finding may provide a way in design and fabrication of transition metal dichalcogenide nanostructures for practical applications