Exergy efficiency analysis of a refurbished dwelling: a case study in Ljubljana,Slovenia

Buildings contribute almost half of the world's carbon dioxide (CO₂) emissions. Energy and water consumption are some of the largest and fastest growing pressures on the global environment. The use of energy is mainly attributed to the heating and cooling of buildings. The type of materials used in the construction of buildings plays a significant role in the life-cycle emissions of each dwelling. Changing the material use in the construction of an existing building and adding insulation could have a major impact on energy use and the environment of the building in its entire life cycle. This paper investigates the amount of exergy savings and the decrease in CO₂ emissions resulting from the refurbishing of an existing building in Ljubljana. This study results from the growing awareness that in the choice of building materials, the designer must consider not only the requirements of the owner and occupier of the building, but also the resulting energy savings, the resource base and the effects of the manufacturing and processing of building materials on the environment. The exergy efficiency of the material use is calculated and the environmental impact assessment of energy and material use is accounted for.     

Eco-material selection using fuzzy TOPSIS method

In the classical multiple attribute decision-making or MADM methods, the ratings and the weights of the criteria are known precisely. However, in eco-material selection exercises, the available data are typically inadequate because of the selection dual quantitative and qualitative natures. Some of the qualitative selection criteria can be rated in several classes rather being expressed by exact numerical values; hence the application of fuzzy concepts in decision-making seems attractive to deal with such kind of ratings. Thusly, the presented study attempts to propose an eco-material selection approach specific to the automobile body panels using a fuzzy technique for order preference by similarity to ideal solution (TOPSIS), to incorporate both numerical and rating-based criteria into one holistic sustainability model. TOPSIS and fuzzy logic can aid the material selection process in translating the design goals and parameters into usable numbers that in turn can be used to rank candidate materials in their closeness to the ideal solution. An additional uniqueness of this study stems from using the fuzzy-TOPSIS as a scoring tool without any assigned weights for the different selection attributes, in order to avoid the bias that is typically associated with other classical MADM, such as quality function deployment, analytical hierarchy process and digital logic.     

土霉素在4种人工湿地基质上的吸附-解吸特性

为了研究土霉素在人工湿地基质床中的行为机制,本实验采用批量平衡方法研究了壤土、煤灰渣、粗砂和细砂等4种人工湿地基质材料对土霉素的吸附、解吸特性。结果表明,土霉素在人工湿地基质材料上的吸附可分为前4小时的快速吸附阶段和之后的慢速吸附阶段,14 h后达到吸附平衡,这一吸附平衡时间明显低于一般人工湿地系统的水力停留时间。可以认为,土霉素在人工湿地中有足够的时间吸附于基质层上,其吸附量的大小主要取决于基质材料的性质。土霉素在4种基质材料上的等温吸附实验表明,吸附等温线均呈非线性,用Freundlich方程能较好地对吸附数据进行非线性拟合。在4种人工湿地基质材料中,煤灰渣对土霉素的吸附作用最强,通过Freundlich方程拟合的吸附容量参数(KF)为280.2;其次为壤土,KF值为129.3;粗砂和细砂的吸附作用较弱,KF值分别为53.2和64.5。人工湿地基质材料对土霉素的吸附能力主要与基质有机质含量、粘粒含量、Fe2O3含量、阳离子交换量和Al2O3含量呈正相关。土霉素在4种人工湿地基质材料上的解吸均存在滞后现象,相对于壤土和煤灰渣,吸附于粗砂和细砂上的土霉素更容易被解吸下来。     

纳米TiO2/硅藻土光催化降解废水中二甲胺

通过凝胶-溶胶法制备纳米TiO2/硅藻土复合催化剂,对常见工业难降解有机污染物二甲胺(DMA)进行了降解实验.采用扫描电镜和X射线衍射技术对催化剂能进行了表征,考察了废水初始浓度、pH、催化剂用量、外加氧化剂对DMA光催化降解效果的影响,进行了降解动力学和降解机理的分析.结果表明,所制催化剂为锐钛矿和金红石混合晶型,均达纳米级,对中低浓度(≤400 mg/L)DMA废水具有良好的降解效果.常温常压、18W紫外汞灯下,3 g/L TiO2/硅藻土对DMA废水(400 mg/L)降解率可达70％以上;其降解反应符合Langmuir-Hinshelwood动力学模型;其可能的降解途径为:二甲胺(DMA)→甲胺(MA)→CO2/CO32-、H2O和NH4+.     

S-K型管式混合器-微絮凝高速过滤的实验研究简

基于2种传统管式混合器的特点,研究了苏尔士-凯尼斯（S-K）新型组合管式混合器在预氧化-微絮凝高速过滤技术中的应用,对苏尔士（Sulzer）管式混合器、凯尼斯（Kenics）管式混合器及S-K型管式混合器高速过滤出水水质进行了对比分析,结果表明,S-K型微絮凝方式对浊度、COD及TP的平均去除率比其他2种混合器混合方式的去除效果提高了5%~10%,分别为80.3%、64.76%和51.15%。S-K型混合器过滤形成的絮体能够充分利用深层滤料,延长过滤周期。     

不同阴极对微生物燃料电池产电性能的影响比较

阴极催化性能及材料对微生物燃料电池(microbial fuel cells,MFCs)的产电特性及制造成本有很大影响。本研究选用金属铂(Pt)、活性炭作为催化剂、聚四氟乙烯(PTFE)和道康宁1-2577作为阴极的扩散层、碳布和不锈钢网作为阴极的基体材料制备得4种阴极,分别考察了相应MFC的产电性能和阴极特性。结果表明,采用传统Pt催化剂+PTFE扩散层+碳布制备成的阴极(Pt-PTC),MFC的最大输出电压为560 mV,最大功率密度为808 mW/m2,而采用活性炭+道康宁1-2577+不锈钢网制备成的阴极(AC-DCS),MFC的最大输出电压为510 mV,最大功率密度为726 mW/m2,两者的MFC产电性能极为接近。SEM结果表明,活性炭催化层表面和道康宁1-2577扩散层分别比Pt催化层及PTFE扩散层的更均匀光滑。阴极线性伏安测定结果表明,AC-DCS与Pt-PTC的电化学氧化性能较为接近。AC-DCS阴极成本仅为Pt-PTC的1/300左右,是一种低成本扩大化生产MFC阴极的新方法。     

脱氮副球菌YF1微生物燃料电池生物阴极脱氮和产电

以脱氮副球菌YF1构建纯种生物阴极微生物燃料电池(microbial fuel cell,MFC)进行脱氮和产电机理的研究。研究结果发现,阴极碳氮比、pH值对产电和脱氮效率有明显影响。当MFC的阴极运行条件pH值为8.0,碳氮比为20时,运行时间15 h时,脱氮率高达100%,输出电压为150 mV。上述结果表明,微生物燃料电池运行过程中,细菌降解硝酸根的机理为将硝酸根还原为N2或者直接将其作为自身的营养物质而利用。循环伏安(CV)与扫描电镜(SEM)的结果表明,在微生物燃料电池运行中,副球菌YF1通过接触导电作为产电的电子供体。     

蓄热式高温带压蒸汽发生器设计

介绍了自制蓄热式高温带压蒸汽发生器的工作原理及运行过程,对炉体结构进行了设计计算,设计并计算了保温层的厚度,通过部分热态实验,验证了高温带压蒸汽发生器设计的合理性和系统运行的可靠性。试验结果表明,经过高温带压蒸汽发生器蓄热室的换热,可以生产出压力在0.2～0.4 MPa、温度在650℃以上的高温过热水蒸气。从而说明系统的整体设计能满足要求。     

复合加筋排水褥垫软土路堤排水设计方法

复合加筋排水褥垫是针对沿海缺砂地区开发的一项可取代水平排水砂垫层、具有水平排水与加筋作用的新型专利技术。本文介绍了复合加筋排水褥垫的性能指标,给出了复合加筋排水褥垫软土路堤排水设计方法,并将复合加筋排水褥垫与水平排水砂垫层的排水性能进行了对比分析。算例结果表明,复合加筋排水褥垫能满足软土路堤排水要求,其排水性能要明显优越于水平排水砂垫层。     

不同吊顶材料对燃烧室内和狭长走廊中烟气危害性的影响

选取建筑用材中几种常用的吊顶材料,研究火源以及火势迁移等因素对狭长走廊中烟气危害性的影响.试验在小尺寸实验台上进行,研究了采用不同吊顶材料时燃烧室和走廊中烟气的体积分数峰值、峰宽时间及到达峰值的时间,揭示了烟气的危害程度.试验表明,不同吊顶材料对火灾中烟气的危害性有明显影响.复合板吊顶材料能够显著增加烟气体积分数峰值并缩短到达峰值的时间,其烟气体积分数峰值约为单纯钢板吊顶情况下的两倍.PVC吊顶材料在同样火灾载荷下的塌落倾向最明显.