Sustainable Disposal of Domestic Sanitary Waste

The study presented is an example of the assessment of the relative sustainability of either option for disposal of domestic sanitary waste, either via the toilet or via the solid waste route. This required an evaluation of the total (social, economic, environmental, and technical) benefit/cost of implementing and adopting the alternative routes and an assessment of public responsiveness to encouragement to change sanitary waste disposal practices. It illustrates how, even for an apparently straightforward either/or question, the assessment of relative sustainability is complex and the amount of data needed to quantify sustainability indicators is prodigious. The study also provides an appraisal of the effectiveness of public campaigns to reduce waterborne disposal. Important information regarding public attitude and behavior in relation to wastewater systems has been acquired and lessons for ways of encouraging behavioral change to more sustainable ways of living have been gleaned.     

集成型空间数据库技术探讨与应用实例

集成型空间数据库的构建过程中,常涉及到空间数据的非结构化特征问题。总结了目前克服此问题的两种技术,即面向对象技术与中间件技术,并对商业化中间件中的空间数据引擎作了标准性、存储结构与图层管理三方面分析。给出了采用空间数据引擎的应用实例,提出了急需解决的问题。
     

接种氧化亚氮(N2O)还原细菌YSQ030对复垦土壤N2O排放和氮循环关键功能基因的影响

复垦土地是重要的后备土地资源,但通常土壤结构差、有机质和养分含量低;增施有机肥是快速提升地力的关键途径,但会造成温室气体如氧化亚氮(N₂O)的大量排放.接种具有N₂O还原功能的植物根际促生菌(PGPR)不仅能够减少温室气体排放,还能促进作物生长.本研究以一株具有N₂O还原功能的PGPR反硝化无色杆菌(Achromobacter denitrificans) YSQ030为供试菌株,明确接种YSQ030对施用有机肥的复垦土壤N₂O排放和氮循环关键功能基因的影响.通过设置施用有机无机复混肥和羊粪有机肥的土壤微宇宙试验,利用气相色谱仪分析接种YSQ030后土壤N₂O排放通量,进一步计算累积排放量;在试验结束后分析土壤pH、EC(电导率)、硝态氮和铵态氮含量,并利用实时荧光定量PRC分析土壤硝化功能基因(AOA amoA和AOB amoA)和反硝化功能基因(nirS、nirK、nosZ Ⅰ 和nosZ Ⅱ)的丰度.结果显示,施用有机无机复混肥和羊粪有机肥的土壤中接种YSQ030明显减少复垦土壤N₂O排放,N₂O排放量最大减少分别达90.4％和30.6％.施用有机无机复混肥处理的N₂O排放量远高于施用羊粪有机肥处理,这可能是由于施用有机无机复混肥的土壤与施用羊粪有机肥的土壤相比,土壤中编码反硝化细菌N₂O还原酶基因nosZ Ⅰ 和非典型反硝化细菌N₂O还原酶基因nosZ Ⅱ 基因丰度较低.施用有机无机复混肥均显著降低土壤硝化和反硝化功能基因丰度,而施用羊粪有机肥对土壤硝化和反硝化功能基因丰度大多没有明显影响.本研究表明,接种YSQ030能够减少施用有机肥土壤的N₂O排放,将为复垦土壤地力提升和N₂O减排提供科学依据,也将为研发新型微生物肥料或生物有机肥提供核心菌种资源.     

Properties of amidated pectins. I. Preparation and characterization of amidated pectins and amidated pectic acids

The preparation of high molecular weight pectic acids with varying degrees of amidation (15–61%) is described. The samples are characterized by analytical parameters, viscosity and behaviour on gel permeation and ion-exchange chromatography columns. Results show that the monomer composition is not changed and that aggregation may occur in aqueous solution of highly amidated pectic acids.     

Ceramic components in passenger-car diesel engines

Components for diesel engines are being developed from various ceramic materials. The properties of the most interesting materials, the process technology and the designs of the components are described. Experimental results with thermal insulation of combustion chamber components and with wear resistance shielding of valve train components are being reported. The response of turbochargers using low density ceramic rotors is tested and the temperature loads on ceramic particulate filters during regeneration are being measured.     

岩体质量Q系统计算平台的开发与应用

岩体质量分类Q系统是目前应用最广的岩体质量分类方法之一.为了实时准确地判断岩体稳定性,提高工作效率,并将Q系统岩体分类信息化,以Python为开发语言,利用Web网络技术和数据库技术开发了岩体质量Q系统计算平台.详细介绍了岩体质量Q系统计算平台的开发原理和操作流程,将Q系统与网页界面结合,并通过网页展示Q系统图解与支护...     

Non-isobaric phenomena in gaseous diffusion through adsorbent porous solids

Pressure gradients were generated during counter-diffusion of adsorbing gases within pelletized activated carbon pellets and modified molecular-sieving carbon pellets even though external isobaric conditions were maintained. Such non-isobaric phenomena were analysed with a zone reaction model which incorporated a flow equation, adsorption equilibrium relationships of gases, and adsorption rates. It was found that pressure gradients are induced within the porous solids by differences in diffusion rates, adsorptivities and adsorption rates of the counter-diffusing gases.     

Elutriation from fluidized beds—II. Disengagement of particles from gas in the freeboard

The freeboard above a fluidized bed is the dilute phase region in which the gas and particles disengage. The freeboard container is normally cylindrical and usually of the same diameter as the bed but sometimes larger.Theory is given to describe horizontal turbulent diffusion of fine particles towards the freeboard walls. On reaching the walls, the fine particles descend as a falling film which may drag down gas and thus generate a gas circulation current in the freeboard. This theory gives predictions of (1) upward flux of fine particles and (2) particle concentration, both as functions of distance above the bed surface. These predictions are in reasonable agreement with (1) measurements, using isokinetic sampling, of upward particle flux above an 0.6 m diameter bed of polymer particles of mean diameter 760 μm, and (2) measurements of particle concentration at five levels above a 0.3 m square bed containing a mixture of 73 and 370 μm particles, using entrapment of particles between horizontal shutters in the freeboard.The theory gives a working formula to predict the transport disengaging height (TDH) in reasonable agreement with published data. The theory predicts that the TDH increases with freeboard diameter. The theory predicts, and experiments confirm, that the TDH can be reduced by inserting vertical baffles into the freeboard.The circulation of freeboard gas, generated by the fine particle motion, may explain the published observations (Geldart, D., Cullinan, J., Georghiades, S., Gilvray, D. and Pope, D.J., 1979, Trans. Inst. Chem. Engrs57, 269) that adding fine particles increases the elutriation of coarse particles.     

一体式膜-生物反应器经济曝气量的试验研究

增大曝气量一方面可提高膜面液体循环流速,从而减缓污泥在膜表面的沉积,降低膜污染形成速率;另一方面曝气量的增加也造成污泥粒径分布的变化,使混合液中细小污泥颗粒增多,从而导致膜孔堵塞,引起膜污染速率增加.一定污泥浓度下存在一个经济的曝气量,使得污泥絮体不大量在膜表面沉积,同时也不会产生更多的细小污泥粒子.实验考察了一体式膜-生物反应器在不同污泥浓度、不同曝气量下膜污染的发展趋势.实验结果:在污泥浓度为3,6,8和10g/L下的经济曝气量分别为36,72,84,120m3/(m2·h),经济曝气量随污泥浓度的增大而增加.