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371.
高放核废料深地质处置中,膨润土缓冲/回填材料需要满足低渗透性要求,实现阻滞地下水入渗和放射性核素泄漏的目标。增强膨润土防渗能力的常规方法是采用增大压实功提高其密实度,但该方法十分耗时耗能。为此,尝试从调整膨润土团(颗)粒级配角度,探究提高压实度的有效方法。首先,配置不同团粒级配和初始含水率的膨润土试样,再利用压力机压实到45 kN;最后,采用液氮冻干法干燥不同状态的试样,通过压汞仪获得其孔隙分布曲线。结果表明:相同压实荷载下(45 kN),干密度随含水率呈先增大后减小的整体变化趋势,含水率约为20%时压实效果最佳,其中O-B组合与A-B-3组合具有双峰特征;另外,通过调整团粒级配,压实效果显著提升,最大干密度由1.64 g/cm-3提高到1.72 g/cm3,其中A-B-3团粒组合效果最好。孔隙分布曲线表明,压实荷载只能压缩-3.59~0.188 μm-范围的孔隙,而对26 nm左右的孔隙没有影响。当含水率超过20%时,依靠增大压实荷载不能提高其压实度,但当改变团粒组合后,却可以有效提高其压实性能。 相似文献
372.
建立我国海滩质量标准分级体系的探讨 总被引:1,自引:0,他引:1
在参考国内外主要海滩质量标准评价体系的基础上,论文根据我国海滩的具体状况,提出适合我国国情的海滩质量标准体系。标准体系包括自然和社会经济两类共54个因子,对不同开发程度的海滩实行不同的评分标准,最终将海滩分为钻石、金、银、铜及不及格5个等级。论文对山东和福建共6个不同开发程度(开发成熟,低度开发/未开发)的海滩进行了试点应用,结果表明,厦门黄厝得分最高,霞浦大京得分最低。同时解释所提出标准的适用性,并对海滩资源可持续开发利用提出管理对策。 相似文献
373.
通过林可霉素菌渣的中温厌氧消化摇瓶实验,比较不同的含固率(3%、5%、8%、10%)和接种比(0.5、1、2、3)对菌渣产甲烷能力的影响,以确定菌渣厌氧消化的最优工艺条件.结果表明,在研究参数范围内,含固率越低,接种比越高,越有利于甲烷的产生;经过10d的培养,在含固率为3%、接种比为3时的工况中,菌渣的挥发性固体(VS)累计净产甲烷量最高,为106 mL/g;而含固率>5%、接种比2的液态发酵工艺,此条件既能保证厌氧消化不受消化产物(胺和挥发性有机酸)积累的抑制,也可以缓冲菌渣中残留林可霉素对消化微生物可能产生的抑制效应. 相似文献
374.
375.
Jiang He Chang-Wei Lü Hong-Xi Xue Ying Liang Saruli Bai Ying Sun Li-Li Shen Na Mi Qing-Yun Fan 《Environmental geochemistry and health》2010,32(1):45-58
This paper analyses the contents and species distributions of rare earth elements (REEs) in the water-suspended particulate-sediment
system of the Baotou section of the Yellow River, China, with known anthropogenic REE input from industrial discharges. The
major forms of REEs were suspended and dissolved in the mainstream and the tributaries of the Baotou section, respectively.
The concentrations of the dissolved and suspended REEs had the same trends in the overlying water along the mainstream, which
increased from the Seqi section (site A) to the mouth of the Sidaosha River (site D), reaching a maximum value at site D,
and tending to decrease thereafter. The contents of REEs in sediment cores showed enrichment with light rare earth elements
(LREEs). The bound to carbonates and to Fe–Mn oxides are the major forms of REE in the secondary phase and the REE exhibited
LREE enrichment pattern and moderate Eu depletion in suspended particulates and surface sediments. The contents and species
distributions of REEs in the water-suspended particulate-sediment system of the Baotou section suggest that the anthropogenic
source of REEs from Baotou city have enhanced REE accumulation to the Baotou section. This information is important for predicting
possible pollution resulting from anthropogenic REE input into rivers. 相似文献
376.
377.
Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems. As the products of composting can be utilized as a fertilizer, it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost. In this study, batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces. Attention was paid to the characteristics of nitrogen transformation. Under the controlled conditions of temperature at 60°C, moisture content at 60%,anda continuous air supply, more than 70% fecal organic removal was obtained, while merely 17% fecal nitrogen loss was observed over a two-week composting period. The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content. The fecal NH4-N which was the main component of the inorganic nitrogen ( > 90%) decreased rapidly in the first day, decreased at a slower rate over the following days, and finally disappeared entirely. The depletion of NH4-N was accompanied by the accumulation of NH3 gas in the ammonia absorber connected to the reactor. A mass balance between the exhausted NH3 gas and the fecal NH4-N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss. Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer. 相似文献
378.
针对油田采出废水的特点,以粘胶基活性炭纤维为原料,经二次炭化和二次活化方式处理制得ACF样品。以ACF为过滤材料,对延长某采油厂经过沉降、分离处理后的采油废水进行动态吸附实验,实验结果表明:经水蒸汽二次活化得到的ACF样品对选用的油田废水处理效果最佳,其悬浮物颗粒粒径中值0.496μm(<1.0μm)、悬浮物含量为0.77mg/L(<1.0mg/L)。 相似文献
379.
The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes. The experiments were carried out in batches. When the vegetable wastes were mixed with the flower stems at the dry weight ratio of 1 to 13, the overall hydrolysis rate increased by 8%, 12%, and 2% according to the carbon, nitrogen, and total solid (TS) conversion rate, respectively. While the dry weight ratio was designed as 1 to 3, there was a respective rise of 5%, 15%, and 4% in the conversion rate of carbon, nitrogen, and TS. The enhancement of anaerobic hydrolysis from the mixed vegetable wastes and flower stems can be attributed to the formation of volatile fatty acids (VFA) and nutrient supplement like nitrogen content. The maximum VFA concentration can achieve 1.7 g/L owing to the rapid acidification of vegetable wastes, loosing the structure of lignocellulose materials. The statistic bivariate analysis revealed that the hydrolysis performance was significantly related to the physical and biochemical compositions of the feeding substrate. Especially, the soluble carbon concentration in the liquid was significantly positively correlated to the concentration of nitrogen and hemicellulose, and negatively correlated to the concentration of carbon and lignocellulose in the feeding substrate, suggesting that the regulation and control of feedstock can have an important influence on the anaerobic hydrolysis of organic wastes. 相似文献
380.
1 问题的提出
胜利油田各培训机构多年来为油田培养了大批的专业人才。但是,目前安全教育培训仍然采用传统的面对面的教学管理方式,培训计划、培训人员、办班情况、培训内容、成绩单等信息均采用人工记录,上报安全处、劳资处等管理部门的材料还是采用传统的纸质材料,工作效率受到限制。 相似文献