Has water-saving irrigation recovered groundwater in the Hebei Province plains of China?

This study performed a quantitative evaluation of the impact of water-saving irrigation on the groundwater regime in the Hebei Province plains area. In this work, the change in groundwater regime and the contributions of precipitation and water-saving irrigation development were investigated. The results indicate that the groundwater overdraft has been mitigated to some extent, mainly due to changes in precipitation and the implementation of water-saving irrigation, with contributions of 64.3% and 35.7%, respectively, when considering only these two factors. Water-saving irrigation is accepted as an important means for reducing groundwater depletion, but should be used in conjunction with other measures.     

三道沟河干流梯级开发形成的脱水段对生态环境的影响

以三道沟河干流开发为例,主要探讨脱水段对周边居民生活及生态环境的影响,提出较合理的解决方案。通过分析研究八级水电站、十三级贾家营子二级水电站对居民生活及周边生态产生影响,提出了技术可行,经济合理的备选方案。本成果可为同类工程的开发提供参考。     

Piso sto Chorio … I Apantisi stin Krisi einai i Agrotiki Paragogi[Back to the Village … The Answer to the Crisis is Agricultural Production]

In this study, groups of batch experiments were designed to identify the characteristics of alum sludge for arsenic (As) adsorption. Air-dried alum sludge (moisture content 13.9%) collected from a water treatment works in Xi’an, China, was subjected to artificial As-rich wastewater adsorption tests using As₂O₃ as a model As source. Adsorption behaviours were investigated and the results have shown that the Langmuir adsorption isotherm well fits the experimental data (R² = 0.94957–0.99365). The maximum adsorption capacities range from 0.61 to 0.96 mg-As/g when the pH of the As solution was varied from 9.0 to 4.0. The prospects in China for the outcome of this study are discussed. This promising low-cost technique can eradicate As contamination in China.     

泾惠渠灌区地下水位埋深的动态特征及影响因素分析

地下水作为陕西泾惠渠灌区的重要水源,对其动态特征的研究在灌区水资源开发利用方面具有重要的指导意义。根据泾惠渠灌区1981-2010年的地下水位平均埋深资料,采用线性倾向估计法、累积距平法、Sen斜率估计法、Mann-Kendall趋势检验法对泾惠渠灌区地下水位埋深动态序列进行年际变化分析;采用滑动T检验法和双向回归突变分析法分析序列突变性;采用主成分分析法和灰色关联分析法确定影响灌区地下水埋深动态的主要因素。结果表明:灌区1981-2010年地下水位平均埋深基本呈增加趋势,突变点出现在1994年,1994年之前影响灌区地下水埋深动态的主要因素为蒸发量,1994年之后主要影响因素为蒸发量、地下水开采量和灌渠引水量。     

Modeling of thermal processes for internal melt ice-on-coil tank including ice-water density difference

The internal melt ice-on-coil tank with horizontal tubes is used widely for thermal storage. Its discharge process is greatly affected by the ice-water density different. The existing models developed for internal melt ice-on-coil tanks are concentric cylinder models which are applicable to tanks with vertical tubes or when all the water in the tank is frozen, but they do not describe the effect of the ice-water density difference on discharge. This paper introduces an eccentric cylinder model developed especially for the discharge process in a tank with horizontal tubes. The model is simple and is suitable for system simulation. Experimental validation proved the reliability of the model.     

能源微藻无泡采收新方法及其性能

采用低密度浮珠颗粒代替气泡的无泡采收方法,高效低成本采收能源微藻. 以常见能源微藻小球藻为例,以硅硼酸钠为浮珠,比较了浮珠浮选工艺与传统气浮法的区别,通过响应面法优化了浮珠浮选工艺. 结果表明,以硅硼酸钠为浮珠的无泡采收效果较理想,浮珠颗粒粒径、浓度和搅拌速率对采收率影响显著,颗粒直径56 ?m、浓度0.546 g/L、搅拌速率133 r/min的条件下采收率最好,达83.7%.