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排序方式: 共有486条查询结果,搜索用时 15 毫秒
101.
成土母质对土壤团聚体形成的影响 总被引:1,自引:0,他引:1
成土母质对土壤团聚体数量及其稳定性的影响与不同母质所含无机胶体(粘粒、游离氧化物)的差别有关.对浙江省八类母质发育的土壤的团聚体组成的研究表明:母质对土壤团聚体及其水稳定性影响顺次为玄武岩>石灰岩、Q2红土>花岗岩、石英砂岩>泥页岩>紫砂岩>红砂岩.其中母质对5-1mm粒级的水稳性团聚体的影响最为显著. 相似文献
102.
介绍目前环境管理的手段:直接强制性手段,经济手段,技术手段和自愿手段等,分析应用的优缺点,得出几种手段应综合使用,取长补短.举例说明其在中国环境管理中的具体应用.最后,对中国环境管理的发展提出了几点思考建议. 相似文献
103.
Elizabeth R. Mathews Jennifer L. Woo Dean Phillips Nathan Billington Dean Barnett Ashley E. Franks 《环境科学学报(英文版)》2020,32(1):133-148
Controlling hydrogen sulfide (H2S) odors and emissions using a single, effective treatment across a town-scale sewer network is a challenge faced by many water utilities. Implementation of a sewer diversion provided the opportunity to compare the effectiveness of magnesium hydroxide (Mg(OH)2) and two biological dosing compounds (Bioproducts A and B), with different modes of action (MOA), in a field-test across a large sewer network. Mg(OH)2 increases sewer pH allowing suppression of H2S release into the sewer environment while Bioproduct A acts to disrupt microbial communication through quorum sensing (QS), reducing biofilm integrity. Bioproduct B reduces H2S odors by scouring the sewer of fats, oils and grease (FOGs), which provide adhesion points for the microbial biofilm. Results revealed that only Mg(OH)2 altered the microbial community structure and reduced H2S emissions in a live sewer system, whilst Bioproducts A and B did not reduce H2S emissions or have an observable effect on the composition of the microbial community at the dosed site. Study results recommend in situ testing of dosing treatments before implementation across an operational system. 相似文献
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基于生命周期评价方法,考虑混凝土重复再生利用的环境影响分配,对重复再生混凝土的性能和环境影响进行研究,并基于功效系数法优化出混凝土最佳重复再生次数.研究结果表明,再生混凝土的坍落度,强度和电通量随着重复再生循环次数的增加而下降,经3次重复再生后,混凝土28d立方体抗压强度为33.3MPa,满足设计要求,而坍落度和电通量与普通混凝土相比,分别减小和增大了38.9%和85.7%;混凝土材料的生态效率随着混凝土重复再生次数的增加而提高,混凝土材料的GWP、CED和CMR的值均随着混凝土重复再生次数的增加而降低,降低幅度从高到低依次为:CMR > GWP > CED;综合考虑混凝土的坍落度,混凝土抗压强度、电通量、GWP、CED和CMR等6个指标,4种混凝土配合比情景中,混凝土总功效系数从高到低依次为:一次再生混凝土 > 二次再生混凝土 > 三次再生混凝土 > 普通混凝土. 相似文献
107.
《International Journal of Sustainable Engineering》2013,6(2):153-163
This paper focuses on the valuable utilisation of spray dryer ash (SDA) and investigates its performance in concrete for structural applications. Based on the challenges associated with the disposal of coal combustion products (including SDA) and the economic costs linked to cement production, this research seeks to provide an environmentally friendly and more cost-effective concrete product by utilising SDA in partial replacement of cement in concrete. With the exception of a relatively high-sulphur content, SDA exhibits very useful properties that are closely related to Class C fly ash and Portland cement. Experimental tests were carried out to determine the effect of SDA replacement of Portland cement (ranging from 0 to 50% replacement) on the compressive strength, bond strength, freeze-thaw performance and corrosion resistance of concrete. The addition of SDA in non-air entrained concrete provided a general increase in its strength with optimal limits ranging between 25 and 35% replacement. The addition of SDA produced a negligible effect on the freeze-thaw durability of the concrete (air entrained). Results for corrosion performance were not as definitive, but indicate that the use of SDA does not significantly change the likelihood of reinforcing bar corrosion. 相似文献
108.
Diego Romero Jacqueline James Rodrigo Mora Carol D. Hays 《Waste management (New York, N.Y.)》2013,33(7):1659-1666
Cathode ray tube (CRT) glass is considered a hazardous material due to its lead toxicity. In addition, current disposal practices are being phased out due to their adverse environmental impacts. In this project, CRT glass was used as a fine aggregate replacement in concrete. Life-cycle material characterization was conducted by evaluating the durability and strength of the CRT-Concrete. Leaching tests were also conducted to investigate whether the material meets drinking water limits for Pb. Test results show that the plastic state of the CRT-Concrete was affected by the angularity of the glass particles. Moreover, the compressive strength of CRT-Concrete met and exceeded that of the control specimen. However, CRT-Concrete was susceptible to expansive alkali-silica reactions when more than 10% CRT replacement was used. Environmental leaching results show that lead concentrations from CRT-Concrete are below the drinking water limits depending on the CRT volume replacement and if biopolymers are used. 相似文献
109.
为防止地表沉陷,煤矿采空区需要充填,目前采用的充填方法为胶结充填、高水速凝充填等.泡沫混凝土具有质轻、流动性好的特点,可作煤矿采空区的充填材料.制备低水泥用量、含粗颗粒煤矸石的泡沫混凝土对发泡剂的泡沫稳定性要求较高,目前市售的发泡剂难以满足要求.在探讨发泡剂发泡、稳泡原理的基础上,研究了稳泡剂(D)的加入量对发泡液黏度、发泡倍率和泡沫稳定性的影响,以D与十二烷基硫酸钠(SDS)复配,研制出了高泡沫稳定性的发泡剂KD-1,该发泡剂的发泡倍率为21.3,开始泌水时间为7 min,90 min后沉降距为38 mm,并且考察了KD-1与混凝土早强剂的相容性.用此发泡剂制备出了最大粒径为5 mm、煤矸石掺量为63%(质量分数)、体积密度分别为800 kg/m3、900 kg/m3和1000 kg/m3的煤矸石泡沫混凝土,其90d单轴抗压强度分别为0.4 MPa、0.63 MPa和1.75 MPa. 相似文献
110.
中远船务构筑特色安全文化的探索与实践 总被引:2,自引:2,他引:0
王兴如 《中国安全生产科学技术》2006,2(1):80-84
本文主要阐述了在企业核心价值理念孵化牵引下生发的安全文化理念,总结和提炼了具有企业特色的“严、细、真、实、慎”的安全文化,并从制度建设、行为规范以及体现执行力的十大主要措施上,进行了比较系统的论述,对进一步促进企业安全文化建设提出了4个方面的对策。 相似文献