排序方式: 共有63条查询结果,搜索用时 46 毫秒
51.
一体式铝盐絮体-超滤膜净水效能与机制 总被引:1,自引:1,他引:0
一体式膜工艺以其占地面积小、污染物去除效率高等优点在水处理工艺中逐渐应用.然而,长期运行后,传统颗粒性吸附剂存在加剧膜表面损伤的风险,同时大多数研究所用吸附剂价格较高,如纳米铁、碳纳米管等.针对上述问题,本文将铝盐混凝剂水解后形成的松散絮体直接注入膜池,基于腐殖酸(HA)和密云水库原水,考察了一体式絮体-超滤膜工艺运行效能及膜污染行为.结果表明,仅HA过膜时,第12 d跨膜压差(transmembrane pressure,TMP)急剧增至76. 4 k Pa,将膜组件取出经自来水清洗膜表面后TMP降为10. 1 k Pa (13 d),表明滤饼层是膜污染的主要形式,并且运行期间HA平均去除率仅为23. 3%.絮体注入频率、曝气强度及溶液pH能显著影响该工艺运行效能,尤其溶液pH.当采用连续投加方式将43. 2mmol·L-1铝盐絮体注入到pH为6. 0、曝气速率为0. 3 L·min-1膜池内时,膜污染程度显著降低,第12 d时TMP仅增长到19. 5 k Pa,清洗之后TMP降为5. 6 k Pa (13 d),此时HA平均去除率提高至61. 2%.此外,密云水库原水实验表明,当原水直接过膜时,TMP也急剧增加,运行12 d时TMP达到38. 0 k Pa,而清洗膜表面后TMP降低至3. 8 k Pa (13 d),滤饼层仍然为主要污染方式,同时有机质平均去除率为7. 5%.在上述最佳工艺条件下(曝气0. 3 L·min-1、溶液pH 6. 0)投加43. 2mmol·L-1铝盐絮体时,TMP增长也极其缓慢,12 d时仅增至6. 1 k Pa,膜表面清洗后TMP降至2. 3 k Pa (13 d),有机质平均去除率高达58. 6%.本研究表明一体式铝盐絮体-超滤膜在水处理中具有潜在的应用价值. 相似文献
52.
姚善明 《防灾科技学院学报》2006,8(3):98-101
防震减灾工作是一项社会性的系统工程;非政府组织在社会管理和服务中发挥着重要的参与作用。非政府组织参与防震减灾工作,将使防震减灾工作受到事半功倍的效果。本文分析了非政府组织在防震减灾领域的作用,根据我国政府组织发展的实践,提出了在防震减灾管理工作发挥非政府组织作用的思路。 相似文献
54.
苏荣茂 《防灾技术高等专科学校学报》2006,8(2):84-87,133
本文介绍了海淀区地震办公室几年来在防震减灾工作中,更新观念,转换机制,开创防震减灾工作新局面所做的工作,在防灾减灾科普教育基地,举办“北京海淀首届城市防震减灾(国际)论坛”,建设海淀公共安全馆,建设避难场所、志愿者队伍和社会力量动员等方面取得的显著成绩。对于各地区地震办公室的工作开展,有一定的学习和借鉴意义。 相似文献
55.
Louis V. Verchot Meine Van Noordwijk Serigne Kandji Tom Tomich Chin Ong Alain Albrecht Jens Mackensen Cynthia Bantilan K. V. Anupama Cheryl Palm 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):901-918
Agriculture is the human enterprise that is most vulnerable to climate change. Tropical agriculture, particularly subsistence
agriculture is particularly vulnerable, as smallholder farmers do not have adequate resources to adapt to climate change.
While agroforestry may play a significant role in mitigating the atmospheric accumulation of greenhouse gases (GHG), it also
has a role to play in helping smallholder farmers adapt to climate change. In this paper, we examine data on the mitigation
potential of agroforestry in the humid and sub-humid tropics. We then present the scientific evidence that leads to the expectation
that agroforestry also has an important role in climate change adaptation, particularly for small holder farmers. We conclude
with priority research questions that need to be answered concerning the role of agroforestry in both mitigation and adaptation
to climate change. 相似文献
56.
The choice of flood control techniques in Bangladesh is reviewed in the context of a case study on the impact of a small-scale
polder, the Dhaka-Narayanganj-Demra (DND) Project. The results of a questionnaire survey among the urban floodplain residents,
who have settled inside the polder and a control population from outside the polder, indicate that the project has achieved
significant flood alleviation but has also induced considerable environmental degradation due to stagnation of water within
the enclosed embankment. The project also experienced numerous problems of structural instability of embankments during major
flood events. An attempt is made to extrapolate some of these adverse environmental impacts of the polder to the compartmentalization
scheme, which has been proposed by a UNDP-sponsored Flood Policy Study as an innovative technique for floodplain management
in Bangladesh. The findings of the study, however, do not provide an adequate basis for assessing viability of the proposed
compartmentalization scheme. Nonetheless, the study illustrates the usefulness of questionnaire surveys among floodplain residents
for obtaining data for project evaluation. 相似文献
57.
58.
Chi Aloysius Ngong Chinyere C. Onyejiaku Dobdinga Cletus Fonchamnyo Njimanted Godfrey Forgha Njong Mom Aloysius Josaphat Uchechukwu Joe Onwumere 《环境质量管理》2023,32(3):195-202
This paper investigates the nexus between greenhouse gas emissions and poverty alleviation in the Economic Commission of West African States between 1985 and 2020 applying autoregressive distributed lag and Granger causality techniques. The results reveal that carbon dioxide non-significantly relates to gross domestic product per capita positively while nitrous oxide and foreign direct investment impacts gross domestic product per capita positively. Methane negatively impacts gross domestic product per capita. The governments should use conventions to regulate greenhouse gas emissions’ effects on environmental degradation regionally and globally. The study underscores that countries should diversify to cleaner energy sources. This would reduce greenhouse gas emissions in the atmosphere. Massive technological investment is required to mitigate the greenhouse gas emissions’ negative impacts on the environment which create poverty. This policy implication ensures environmental sustainability and reverses the ugly trend of greenhouse gas emissions on poverty. 相似文献
59.
David C. Hall Simeon Ehui Christopher Delgado 《Journal of Agricultural and Environmental Ethics》2004,17(4-5):425-444
Global consumption, production, and trade of livestock products have increased rapidly in the last two decades and are expected to continue. At the same time, safety concerns regarding human and animal disease associated with livestock products are increasing. Efforts to increase public health safety standards aimed at legitimately reducing the risks of human and animal disease have focused internationally on standards to regulate the movement of livestock products. There is concern, though, that measures to regulate these standards internationally, such as the WTO SPS measures that in part aim to open international markets, may marginalize small-scale poor producers. The cycle of poverty they are trying to escape through livestock production may, in fact, widen, leading to increased global poverty, malnutrition, and disease. Developing and developed nations alike should be concerned with public and private efforts to address appropriate food safety policies to reduce the likelihood of this effect. Analysis of the impact on small-scale livestock farmers is needed, as well as solutions that consider joint public and private sector initiatives. Costly farm to table tracking systems are not an option, but locally orchestrated vertically integrated systems may have merit in reducing food safety risks and in providing small-scale farmers with increased access to markets, locally and internationally. Increased scientific and technical capacity, and training of WTO officials from developing nations is also needed. 相似文献
60.
关于我校校训的思考 总被引:1,自引:0,他引:1
齐福荣 《防灾技术高等专科学校学报》2005,7(4):1-6
校训是集中反映学校文化和精神特质的高度精炼的词句;校训的理想特征应具有:稳定性、时代性、个性化、导向性、精炼性。我们必须确立校园文化建设的特色与重点;必须认真搜寻并确立在防灾减灾文化之中凝炼出来的具有灵魂象征的学校精神。从“张衡文化”、“张衡精神”以及中华民族传统文化的精神源泉中,提炼出“崇德博智、扶危定倾”的校训。 相似文献