不同好氧预处理方式对餐厨垃圾产甲烷的影响

为了研究不同好氧预处理方式对餐厨垃圾厌氧消化产甲烷的影响,通过建立3个模拟厌氧生物反应器,研究了传统厌氧生物反应器C1、上层好氧预处理-厌氧生物反应器C2和底部好氧预处理-厌氧生物反应器C3 3种不同操作条件下的产甲烷过程。结果表明,挥发性有机酸的累积使C1始终处于产甲烷滞后阶段;而C2、C3的好氧预处理通过加快易水解酸化组分和过量挥发性有机酸的好氧降解,有效缓解了酸性抑制,产甲烷滞后时间明显缩短至10 d内。第32天C2停止上层曝气后,在27 d内甲烷浓度达到了50%以上,同时,产甲烷速率迅速上升,并在第81天可达到峰值773 mL/(kg·d)。C3在第11天停止底部曝气后,虽然经过22 d的时间甲烷浓度即上升至50%,但之后产甲烷速率经历回落阶段后再次逐渐上升,在实验结束时仅达到517 mL/(kg·d)。上层曝气的好氧预处理方式所需曝气时间相对较长,但其产甲烷启动快,与底部曝气相比,其后期的甲烷化过程更稳定并可达到较高的产甲烷速率。     

响应面法优化黄粉虫幼虫处理餐厨垃圾饲养条件的研究

研究了黄粉虫幼虫处理餐厨垃圾的方法。首先在饲养温度、饲料含水量和饲养密度等条件下进行单因素实验,然后,以利用率为指标,运用响应面法优化了黄粉虫幼虫处理餐厨垃圾的饲养条件,结果表明,最佳饲养条件为饲养温度26.7℃、饲料含水量14.5%、饲养密度4.1头/cm2。在此饲养条件下,黄粉虫对餐厨垃圾利用率理论值为38.72%,实际餐厨垃圾利用率为38.88%,相对误差为0.41%,说明利用黄粉虫幼虫处理餐厨垃圾具有较好的效果。     

河流重金属污染底泥的稳定化实验研究

以实现河道疏浚底泥中富含的重金属Cu、Zn、Ni的稳定化为目标,选用EDTA、DTCR、Na2S、Na2S2O3、膨润土、水泥及自主研发的特殊胶凝材料作为稳定剂,对底泥中的重金属进行固化稳定,通过分析稳定后重金属浸出液浓度及赋存形态变化,探讨各药剂稳定效果,并寻求稳定剂的最佳投加量.研究表明,7种稳定剂对3种重金属的综合稳定化效果由好到差依次为:水泥> 胶凝材料> 膨润土> DTCR> 硫化钠> 硫代硫酸钠> EDTA;对Cu、Zn、Ni单种重金属而言,稳定效果最好的药剂分别为膨润土、胶凝材料及DTCR,而EDTA则使重金属浸出液浓度升高.除EDTA外,其他药剂对重金属Cu和Zn的稳定效果要明显优于Ni.根据稳定后重金属赋存形态变化结果,EDTA可使重金属可交换态比例升高,而膨润土对重金属4种形态分布基本无影响,其他药剂使重金属可交换态比例降低.     

Assessment of Aquifer Vulnerability in an Agricultural Area in Spain Using the DRASTIC Model

The assessment of aquifer vulnerability is a very important task, especially in agricultural areas because the quality and availability of groundwater affects both the sustainability of agriculture and the quality of life. In this study, an integrated approach is considered, with the use of the generic and agricultural DRASTIC models as well as a geographic information system (GIS), to assess groundwater vulnerability in the agricultural area of Barrax, in the province of Albacete, in Spain. Seven parameters—depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone media, and hydraulic conductivity of the aquifer (DRASTIC)—have been considered as weighted layers to enable an accurate groundwater risk mapping. The results of the generic DRASTIC model indicated very low vulnerability to contamination for Barrax groundwater due to limited urban and industrial development in the wider area. However, agricultural activities impose pressure to groundwater resources and the results of the agricultural DRASTIC model show that 6.86% of the study area is characterized by very high, 2.29% by high, 47.28% by medium, 38.28% by low, and the remaining 5.29% by no vulnerability to groundwater contamination. The distribution of nitrate concentration in groundwater in the area under study is quite well correlated with the agricultural DRASTIC vulnerability index. Sensitivity analysis was also performed to acknowledge statistical uncertainty in the estimation of each parameter used, to assess its impact, and thus to identify the most critical parameters that require further investigation. Depth to water and impact of vadose zone are the parameters that had the most noticeable impact on the generic DRASTIC vulnerability index followed by the soil media and topography. In contrast, the agricultural DRASTIC method is more sensitive to the removal of the depth to water parameter followed by the topography and the soil media parameters.     

门式起重机起升动载荷分析

以某工厂门式起重机为研究对象,利用轴套力建模法和编制相应CMD命令文件建立了钢丝绳模型,对部件添加材料属性,并对整机施加相应的约束、载荷和驱动,实现了门式起重机的虚拟样机建模.研究了不同的调速方法对起升动载荷的影响,采用联合仿真法对比分析了串电阻调速和变频调速法对动载荷的影响,为门式起重机的疲劳寿命研究提供数据支撑.     

造纸机械用灰铸铁烘缸定期检验要点分析

灰铸铁烘缸具有特殊的铸造结构特征与灰铸铁材质特点,其定期检验要求不同于常规焊制金属压力容器.本文结合定期检验项目要求及现场检验经验,对造纸机械用灰铸铁烘缸的宏观检验、壁厚测定、无损检测、硬度检测、安全附件及仪表、耐压试验等定期检验项目进行了检验检测要点分析与探讨.     

真菌生物滤池净化苯乙烯废气的研究

采用接种Aspergillus candidus和Penicillium frequentans的真菌生物滤池处理苯乙烯废气,考察苯乙烯在生物滤池中的净化效果和物质转化特性。苯乙烯的进气质量浓度为200～800 mg/m3,气体流量分别为0.28,0.38和0.48 m3/h,对应的气体停留时间分别为60,45和35 s。试验结果表明:苯乙烯在真菌生物滤池中有较好的处理效果,最大去除能力达66.78 g/(m3.h),真菌生物滤池中二氧化碳的产生量和苯乙烯去除量呈线性关系。微生物分析结果表明,接种的Aspergillus candidus和Penicillium frequentans在反应器内能够长期保持优势地位。     

The Relation Between Sandstorms and Strong Winds in Xinjiang,China

With observational data spanning 1961–1999 from 90 meteorological stations in Xinjiang, China, the spatial and temporal characteristics of sandstorms and strong winds, and the contribution of strong winds to the occurrence of sandstormsare analyzed. Moreover, the dominant wind direction and minimumwind speeds during sandstorm periods are discussed. The research shows that although possessing similar climatic trends, sandstorms and strong winds in Xinjiang have opposite geographical distributions, i.e. places with more sandstorms show fewer strong winds. The contribution of strongwinds to sandstorms in northern Xinjiang is larger than that insouthern Xinjiang. The dominant wind directions clearly indicatethe paths of the weather systems that introduced the sandstorms.The minimum wind speeds in the sandstorms were over 10 ms^-1in northern and eastern Xinjiang and in the Turpan and Yanqi Basins of southern Xinjiang. In Tarim Basin of southern Xinjiang,however, the minimum wind speed was about 6–8 ms^-1, and even 6 ms^-1 at its southern edge.     

Impact of Growing Income Inequality on Sustainable Development in China： A Provincial-level Analysis

A growing body of literature has documented the rapidly increasing income disparities that accompanied China＇s economic growth in the 1980s and 1990s, and the driving factors behind this. Growing income inequality in its turn may have important implications for the accumulation of physical capital, human capital, and natural capital and as a consequence for sustainable economic development. The purpose of this paper is to investigate the potential impact of income inequality on savings, human resources and the environment in China. It starts with an overview of the different causal mechanisms through which income inequality may affect the accumulation of physical capital, human capital, and natural capital, and discusses to what extent these causal relationships may be relevant in the case of China. Next, provincial data for the year 2002 are used to explore the relationship between income inequality and different elements of sustainable development in China. It is found that income inequality does not affect aggregate savings levels. Rising inequality, however, contributes to lower health and possibly also to higher fertility levels. It also lowers the use of chemical fertilizers in agriculture and therefore is likely to reduce water pollution. Other types of environmental degradation are not affected.