化学组成对聚氨酯密封胶耐热水性能的影响

有关单独介绍热或潮湿对密封胶降解性能影响的研究已经有很多，但热和水对密封胶耐久性的共同影响却很少受到关注。在一项涉及将二甲苯基胺树脂完全曝露在80℃水中达90d的研究中，用傅丽叶变换红外光谱(FTllIR)验证了这一事实：高温下的水将比通常的湿汽更易促使老化。该研究还得出，热水的短期作用是：在有应力存在的情况下发生在试件内部的酯基基团的水解会引起未反应酸酐的水解和浸出，而未受应力作用的试件则不受影响。研究同时还表明，当把密封胶浸泡在较高温度的水中     

冷凝热回收系统中的热水系统设计探讨

结合一座典型星级酒店,提出了一套应用冷凝热回收的热水系统设计方案,并通过对补水方式、运行工况等内容的优化设计进一步降低能耗。     

浸水车辙试验评价沥青路面抗水损害性的研究

通过浸水马歇尔试验、冻融劈裂试验以及浸水车辙试验分析评价某高速公路路面沥青混合料的抗水损害性能,为提高玄武岩沥青混凝土的抗水损害性能提供一定的参考意见。     

地热水利用工程设计探讨

西安地热水的性质 ,以市内不同区域地热水物质含量为依据 ,分析了地热水开发利用的方向 .对工程设计中管材选用进行对比 ,提出了适用于地热水的经济型管材 ,并对地热水处理工艺流程常规工艺及实例进行了分析探讨     

Impact of water stagnation in residential cold and hot water plumbing on concentrations of trihalomethanes and haloacetic acids

This study demonstrates that levels of trihalomethanes (THMs) increase considerably when cold water stagnates in residential pipes and, more significantly, when water remains in the hot water tank. Levels of haloacetic acids (HAAs) increase as well in both cases, but less significantly in comparison to THMs. The study also demonstrates that in both the plumbing system and residential hot water tank, chlorinated and brominated DBP species do not behave in the same manner. Finally, the study shows that sustained use of water in households helps to maintain THM and HAA levels close to those found in water of the distribution system. The results are useful to identify methods of indoor water use that minimize population exposure to DBPs and improve DBP exposure assessment for epidemiological studies.     

我国寒冷地区利用热泵技术供应生活热水的经济性分析

本文以我国典型冬季寒冷地区——北京为例。对土壤源热泵、水源热泵和空气源热泵技术供应生活热水的经济性进行了详细分析。结果发现．空气源热泵与其他两种热泵相比经济性优势明显。     

Experimental investigations of a decentralized system for heating and hot water generation in a residential building

Nowadays, modern heat supply technologies are preferred by the decentralized municipal sector because they considerably reduce heat transfer losses. One such solution is a heating system using residential thermal stations (RTS). The advantages of a heating system with RTS, as compared with hot water storage vessels, include stabilizing heat costs, saving energy and a decrease in heat transfer losses.This paper presents the results of an experiment investigating heat consumption in a residential building using RTS. The building, located in Lublin, Poland, was supplied by the local district heating network. The energy consumption was monitored from April 2007 to April 2009. The efficiency of this system was 71.4% during the period when heat was required (winter) and 61.5% during the summer; an annual average efficiency of 67.1%. The energy consumption of the space heating system varied from 0.03 to 0.53 GJ m⁻² of the flat's surface area, with the average value being 0.22 GJ m⁻². The influences of the location of the flat within the building and the surface area of the flat on the quantity of heat required for space heating were analysed. Specific attention was paid to the occurrence of local heat flows between flats.     

集中热水供应系统设计探讨

介绍了集中热水供应系统热水定额的选择方法、常用热源的选择、系统单双管制的确定依据、不同热水管材的适用范围,并建议因地制宜的采用热水循环管道同程布置与配水管道布置成环的管道布置形式。     

医院住院楼的生活冷热水系统设计

以灵石县人民医院住院楼为背景,对住院楼的生活给水系统设计与生活热水系统设计进行了较详细的阐述,并对管材选用作了分析,最后总结了该医院住院楼生活冷热水系统设计的特点,以指导类似工程设计。     

吸水率对蒸压粉煤灰砖耐水性的影响

通过不同含水率和不同吸水率蒸压粉煤灰砖的抗压强度和抗折强度试验,分析了含水率与吸水率对蒸压粉煤灰砖的抗压强度和抗折强度的影响,并与美国规范进行比较,为我国标准中的抗压强度试件的含水率要求和砖的最大吸水率提出了建议。     

城市生态化水系统规划的若干问题探讨

分析了我国大城市未来的发展趋势与面临的挑战,对城市水系统规划存在的需水量增长与水资源有限的矛盾,气候变化引起雨洪与排水能力有限的矛盾进行了研究,并深入挖掘了问题产生的原因,以生态化理念从四个方面提出了规划应对策略。     

Parameters predictive of Legionella contamination in hot water systems: association with trace elements and heterotrophic plate counts

The contamination of hot water samples with Legionella spp. was studied in relation to temperature, total hardness, trace element concentrations (iron, zinc, manganese, and copper) and heterotrophic plate counts (HPC) at both 22 and 37 °C. Factor analysis and receiver operating characteristic (ROC) curves were used to establish the cut-off of water parameters as predictors for Legionella contamination. Legionella spp. was isolated in 194 out of 408 samples (47.5%), with Legionella pneumophila being the most common (92.8%). After multiple logistic regression analysis, the risk for legionellae colonisation was positively associated with Mn levels >6 μg l⁻¹, HPC at 22 °C >27 CFU l⁻¹, and negatively with temperature >55 °C and Cu levels >50 μg l⁻¹. Multiple regression analysis revealed that Legionella spp. counts were positively associated with Mn, HPC at 37 °C and Zn and negatively associated with temperature. Only 1 out of the 97 samples (1%) having a Mn concentration, an HPC at 22 °C and an HPC at 37 °C below the respective median values exhibited a Legionella spp. concentration exceeding 10⁴ CFU l⁻¹vs. 41 out of the 89 samples (46.1%) with the three parameters above the medians. Our results show a qualitative and quantitative relationship between Legionella spp., the Mn concentration and heterotrophic plate counts in hot water samples from different buildings, suggesting that these parameters should be included in a water safety plan. The role of manganese in biofilm formation and its possible involvement in the mechanisms favouring Legionella survival and growth in water niches should be investigated further.     

防水涂料耐水性能的研究

对单、双组分聚氨酯防水涂料和硅丙水性防水涂料涂膜的耐水性能进行了试验。结果表明，由于固化反应机理不同，就耐水性能而言，单组分湿汽固化型聚氨酯防水涂料要优于双组分反应固化型涂膜性能，而水性防水涂料至少并不适宜用作地下防水材料。     

白云岩自然吸水特性试验研究

水对岩石强度的影响极其复杂,含水的岩石强度指标表征折减,而吸水率是主导岩石强度指标弱化的关键因素。为探讨吸水率对岩石抗剪强度指标的影响规律,以白云岩为研究对象,进行粉晶X-衍射成分分析、浸水试验及直剪试验测试研究分析,结果表明：白云岩自然吸水率偏低,且与时间呈良好的对数关系;岩石强度随浸水时间的增加其抗剪强度指标参数c、φ明显弱化;白云岩吸水率与明显湿度百分比关系密切,以明显湿度百分比量化岩石吸水率,两者呈现良好的二次函数关系。     

某生活区热水供暖系统存在的问题及对策

结合山橡集团公司生活区供暖状况，就其供热系统存在的问题，从采暖近热远冷，立管散热器时冷时热等方面作了阐述，并利用工程热力学及传热学理论进行了原因分析，提出了解决办法。     

青龙煤矿开采对水环境的影响

在分析青龙煤矿地质及水文地质条件的基础上,通过对导水裂缝带发育高度、突水系数的预测计算,探讨了煤矿开采对地表水、地下水环境的影响,为煤矿的长远开采规划和矿区环境恢复治理提供了理论依据。     

Influence of pH on bioactivity of cinnamon oil against Legionella pneumophila and its disinfection efficacy in hot springs

Cinnamon oil extracted from leaves of Cinnamomum osmophloeum has recently been proved as a promising antibacterial agent against Legionella pneumophila, an etiological agent of human pneumonia known as Legionnaires' disease. However, the pH effects on the efficacy of cinnamon oil against L. pneumophila and its applicability to recreational spring water remain unknown. We therefore determined the bactericidal activity of cinnamon oil at pH 3-10 in phosphate-buffered saline (PBS) and in four kinds of springs with various conductivity (259-5595 μs cm⁻¹) and pH (2.1-7.7) levels. Results show L. pneumophila cells were more susceptible to cinnamon oil at pH 8-10 than at pH 4-6 in PBS, which became more evident as increasing contact time from 10 to 60 min. An increase in concentration of cinnamon oil and contact time significantly increased the anti-L. pneumophila activity (P ≤ 0.001), indicating a consistent biocidal effect regardless of pH. Interestingly, this dose-response biocidal effect was also observed in spring waters. Moreover, L. pneumophila of 4 log CFU ml⁻¹ in spring waters was completely inactivated within 60 min by cinnamon oil at 300-750 μg ml⁻¹, with the highest inactivation in alkaline hydrogen carbonate spring. The great bioactivity of cinnamon oil demonstrates its potential to be used to control Legionella growth in recreational spring water and possibly other niches generally at basic pH, e.g., cooling towers.     

供水管网节点水龄变化规律研究

运用EPANET2管网水力水质计算机模拟软件,对两种不同形式的管网进行分析,模拟了同一管网中不同位置的节点水龄变化,分析总结供水管网节点水龄的变化规律,为进一步研究节点水龄与余氯的变化关系,及供水管网中水质安全性评价和水质改善提供了参考.     

集中供热系统中热水供应用户的工况分析

分析集中供热管网与热水供应热用户水力或热力工况变化时的相互影响规律。