Comparative study on dam site selection in the pre-feasibility stage of Shitouzhai Hydropower Station

The selection of dam site is the key content in the early stage of hydropower station project. Based on the hydrology, topographic and geological conditions, kinetic energy economic indexes, flood loss of reservoir, project layout, electromechanical and metal structure, construction conditions and project investment of the proposed dam site, this paper makes an in-depth analysis of the dam site selection in the pre-feasibility stage of Shitouzhai Hydropower Station, in order to provide beneficial inspiration for the design of similar projects

Design and Experiment of Lightweight Dual-Mode Automatic Variable-Rate Fertilization Device and Control System

China’s agricultural facilities are developing rapidly and are mainly operated through household contracting. Due to a lack of suitable variable-rate fertilization devices, manual and blind fertilization still widely exists, resulting in fertilizer waste and environmental pollution. Meanwhile, existing fertilization devices cannot simultaneously meet the needs of different fertilization methods for crop cultivation, increasing the cost of mechanized fertilization. This study developed a lightweight dual-mode automatic variable-rate fertilization device and control system for strip fertilization and spreading fertilization. The least squares method was used to analyze the amount of fertilizer discharged per second at different volumes and rotational speeds of the fertilization device. The quadratic polynomial model fits well, with determination coefficients greater than 0.99. The automatic variable strip fertilization and spreading fertilization control models were established. Experiments with strip fertilization and spreading fertilization were carried out. The results of strip fertilization experiments show that the maximum relative error (Re) for granular nitrogen fertilizer (NF) was 6.81%, compound fertilizer (CF) was 6.2%, organic compound fertilizer (OCF) was 6.83%, and the maximum coefficient of variation (Cv) of uniformity was 8.91%. The results of spreading fertilization experiments show that the maximum Re of granular NF was 7.31%, granular CF was 6.76%, granular OCF was 7.43%, the Cv of lateral uniformity was 9.88%, and the Cv of total uniformity was 14.17%. The developed fertilization device and control system can meet the needs of different fertilization amounts, types, and methods for facility crop cultivation at different stages. This study’s results can provide a theoretical basis and technical support for designing and optimizing multifunctional precision variable-rate fertilization devices and control systems

Water-carbon trade-off in China's coal power industry.

The energy sector is increasingly facing water scarcity constraints in many regions around the globe, especially in China, where the unprecedented large-scale construction of coal-fired thermal power plants is taking place in its extremely arid northwest regions. As a response to water scarcity, air-cooled coal power plants have experienced dramatic diffusion in China since the middle 2000s. By the end of 2012, air-cooled coal-fired thermal power plants in China amounted to 112 GW, making up 14% of China's thermal power generation capacity. But the water conservation benefit of air-cooled units is achieved at the cost of lower thermal efficiency and consequently higher carbon emission intensity. We estimate that in 2012 the deployment of air-cooled units contributed an additional 24.3-31.9 million tonnes of CO2 emissions (equivalent to 0.7-1.0% of the total CO2 emissions by China's electric power sector), while saving 832-942 million m(3) of consumptive water use (about 60% of the total annual water use of Beijing) when compared to a scenario with water-cooled plants. Additional CO2 emissions from air-cooled plants largely offset the CO2 emissions reduction benefits from Chinese policies of retiring small and outdated coal plants. This water-carbon trade-off is poised to become even more significant by 2020, as air-cooled units are expected to grow by a factor of 2-260 GW, accounting for 22% of China's total coal-fired power generation capacity

Water−Carbon Trade-off in China’s Coal Power Industry

The energy sector is increasingly facing water scarcity constraints in many regions around the globe, especially in China, where the unprecedented large-scale construction of coal-fired thermal power plants is taking place in its extremely arid northwest regions. As a response to water scarcity, air-cooled coal power plants have experienced dramatic diffusion in China since the middle 2000s. By the end of 2012, air-cooled coal-fired thermal power plants in China amounted to 112 GW, making up 14% of China’s thermal power generation capacity. But the water conservation benefit of air-cooled units is achieved at the cost of lower thermal efficiency and consequently higher carbon emission intensity. We estimate that in 2012 the deployment of air-cooled units contributed an additional 24.3–31.9 million tonnes of CO₂ emissions (equivalent to 0.7–1.0% of the total CO₂ emissions by China’s electric power sector), while saving 832–942 million m³ of consumptive water use (about 60% of the total annual water use of Beijing) when compared to a scenario with water-cooled plants. Additional CO₂ emissions from air-cooled plants largely offset the CO₂ emissions reduction benefits from Chinese policies of retiring small and outdated coal plants. This water–carbon trade-off is poised to become even more significant by 2020, as air-cooled units are expected to grow by a factor of 2–260 GW, accounting for 22% of China’s total coal-fired power generation capacity

Water−Carbon Trade-off in China’s Coal Power Industry

The energy sector is increasingly facing water scarcity constraints in many regions around the globe, especially in China, where the unprecedented large-scale construction of coal-fired thermal power plants is taking place in its extremely arid northwest regions. As a response to water scarcity, air-cooled coal power plants have experienced dramatic diffusion in China since the middle 2000s. By the end of 2012, air-cooled coal-fired thermal power plants in China amounted to 112 GW, making up 14% of China’s thermal power generation capacity. But the water conservation benefit of air-cooled units is achieved at the cost of lower thermal efficiency and consequently higher carbon emission intensity. We estimate that in 2012 the deployment of air-cooled units contributed an additional 24.3–31.9 million tonnes of CO₂ emissions (equivalent to 0.7–1.0% of the total CO₂ emissions by China’s electric power sector), while saving 832–942 million m³ of consumptive water use (about 60% of the total annual water use of Beijing) when compared to a scenario with water-cooled plants. Additional CO₂ emissions from air-cooled plants largely offset the CO₂ emissions reduction benefits from Chinese policies of retiring small and outdated coal plants. This water–carbon trade-off is poised to become even more significant by 2020, as air-cooled units are expected to grow by a factor of 2–260 GW, accounting for 22% of China’s total coal-fired power generation capacity

Enhanced anti-hepatocarcinoma efficacy by GLUT1 targeting and cellular microenvironment-responsive PAMAM–camptothecin conjugate

<p>The efficient targeting of drugs to tumor cell and subsequent rapid drug release remain primary challenges in the development of nanomedicines for cancer therapy. Here, we constructed a glucose transporter 1 (GLUT1)-targeting and tumor cell microenvironment-sensitive drug release Glucose–PEG–PAMAM-s-s–Camptothecin-Cy7 (GPCC) conjugate to tackle the dilemma. The conjugate was characterized by a small particle size, spherical shape, and glutathione (GSH)-sensitive drug release. <i>In vitro</i> tumor targeting was explored in monolayer (2D) and multilayer tumor spheroid (3D) HepG2 cancer cell models (GLUT1⁺). The cellular uptake of GPCC was higher than that in the control groups and that in normal L02 cells (GLUT1⁻), likely due to the conjugated glucose moiety. Moreover, the GPCC conjugate exhibited stronger cytotoxicity, higher S arrest and enhanced apoptosis and necrosis rate in HepG2 cells than control groups but not L02 cells. However, the cytotoxicity of GPCC was lower than that of free CPT, which could be explained by the slower release of CPT from the GPCC compared with free CPT. Additional <i>in vivo</i> tumor targeting experiments demonstrated the superior tumor-targeting ability of the GPCC conjugate, which significantly accumulated in tumor meanwhile minimize in normal tissues compared with control groups. The GPCC conjugate showed better pharmacokinetic properties, enabling a prolonged circulation time and increased camptothecin area under the curve (AUC). These features contributed to better therapeutic efficacy and lower toxicity in H22 hepatocarcinoma tumor-bearing mice. The GLUT1-targeting, GSH-sensitive GPCC conjugate provides an efficient, safe and economic approach for tumor cell targeted drug delivery.</p