Preparation and characterization of fatty acid ester/building material composites for thermal energy storage in buildings

In this study, fatty acid ester/building material composites as novel form-stable phase change materials (PCMs) were prepared by absorbing liquid fatty acid esters into porous network of conventional building materials. In the composite erythritol tetrapalmitate (ETP) and erythritol tetrastearate (ETS) esters were used as PCM for thermal energy storage, and cement and gypsum used as supporting material. The composite PCMs were characterized using scanning electron microscope (SEM) and Fourier transformation infrared (FT-IR) analysis technique. The SEM results showed that the esters were confined in the porous network of the cement and gypsum. Thermal properties and thermal stabilities of the composite PCMs were determined by using differential scanning calorimetry (DSC) and thermal gravimetric (TG) analysis techniques. DSC results showed that the melting temperatures and the latent heats of the prepared composite PCMs were in range of 21.6-32.3 °C and 35.9-43.3 J/g, respectively. TG analysis indicated that the composite PCMs had good thermal stability. The thermal cycling test including 1000 heating and cooling process was conducted to determine the thermal reliability of the composite PCMs and the test results revealed that the composite PCMs have good thermal reliability and chemical stability.     

Linear correlation between inactivation of E. coli and OH radical concentration in TiO2 photocatalytic disinfection

The biocidal action of the TiO2 photocatalyst has been now well recognized from massive experimental evidences, which demonstrates that the photocatalytic disinfection process could be technically feasible. However, the understanding on the photochemical mechanism of the biocidal action largely remains unclear. In particular, the identity of main acting photooxidants and their roles in the mechanism of killing microorganisms is under active investigation. It is generally accepted that reactive oxygen species (ROS) and OH radicals play the role. The aim of this study is to determine how the OH radical, acting either independently or in collaboration with other ROS, is quantitatively related to the inactivation of E. coli. The steady-state concentrations of OH radicals ([*OH]ss) in UV-illuminated TiO2 suspensions could be quantified from the measured photocatalytic degradation rates of p-chlorobenzoic acid (a probe compound) and its literature bimolecular rate constant with OH radicals. The results demonstrated an excellent linear correlation between [*OH]ss and the rates of E. coli inactivation, which indicates that the OH radical is the primary oxidant species responsible for inactivating E. coli in the UV/TiO2 process. The CT value of OH radical for achieving 2 log E. coli inactivation was initially found to be 0.8x10(-5) mg min/l, as predicted by the delayed Chick-Watson model. Although the primary role of OH radicals in photocatalytic disinfection processes has been frequently assumed, this is the first quantitative demonstration that the concentration of OH radicals and the biocidal activity is linearly correlated.     

Relative survival of Escherichia coli and Salmonella typhimurium in a tropical estuary

Microcosm studies have been carried out to find out the relative survival of Escherichia coli and Salmonella typhimurium in a tropical estuary. Survival has been assessed in relation to the important self-purifying parameters such as biotic factors contained in the estuarine water, toxicity due to the dissolved organic and antibiotic substances in the water and the sunlight. The results revealed that sunlight is the most important inactivating factor on the survival of E. coli and S. typhimurium in the estuarine water. While the biological factors contained in the estuarine water such as protozoans and bacteriophages also exerted considerable inactivation of these organisms, the composition of the water with all its dissolved organic and inorganic substances was not damaging to the test organisms. Results also indicated better survival capacity of E. coli cells under all test conditions when compared to S. typhimurium.     

Self-cleaning and colour-preserving efficiency of photocatalytic concrete: case study of the Jubilee Church in Rome

ABSTRACT

The Jubilee Church in the south-eastern outskirts of Rome is one of the first buildings constructed with super white reinforced concrete with self-cleaning photocatalytic cement. However, 16 years after the opening of the building, the self-cleaning and colour-preserving properties arising from the titania particles (TiO2) within the concrete mix are not meeting the design requirements and the concrete is showing premature evidence of decay. While the form of the decay is affecting the appearance of the building and not its structural soundness, the ageing pattern of the building's components is resulting in a high maintenance cost, one not easily affordable within the ordinary budget supported by a small parish. This study comprises the first comprehensive step in understanding the causes of the accelerated ageing pattern of the concrete, highlighting methods to improve the long-term durability of the concrete and therefore reduce the cost of its maintenance. Moreover, this research offered the opportunity to test the durability and the effectiveness of the TiO₂ in the real conditions on an actual building featuring non-standard geometries. The findings highlight how the ageing pattern directly connects with the geometry of the building and inadequate consideration of the local weathering at the design stage.     

Genetic diversity of Escherichia coli isolates in irrigation water and associated sediments: implications for source tracking

Identifying the sources of fecal contaminants in surface water bodies such as rivers and lakes is of significant importance for environmental quality, food safety and regulatory purposes. Current DNA library-based source tracking approaches rely on the comparison of the genetic relatedness among the fecal contaminants. The objective of this study was to determine the genetic relatedness of Escherichia coli isolated from irrigation water and associated sediments using pulse field gel electrophoresis (PFGE) and to evaluate the genetic stability of the E. coli PFGE patterns. The isolates were obtained over a 4-month period from specific locations within irrigation canals and sediments associated with the Rio Grande River along the Texas-Mexico border. Fifty E. coli isolates were genotyped using PFGE. Different E. coli genotypes were identified among samples collected in 11 different locations. Some isolates obtained over successive months showed similar genotypic patterns. In the laboratory experiment, the PFGE pattern of one E. coli strain changed during survival in irrigation water. The genetic relatedness of this strain changed from >95% to <83% over 8-week survival. These results imply that PFGE is of such extreme resolution that it may be a challenging task to rely solely on a PFGE-based source tracking DNA fingerprint library for large watersheds.     

Effects of humic acid and electrolytes on photocatalytic reactivity and transport of carbon nanoparticle aggregates in water

The effects of naturally occurring macromolecules such as humic acid (HA) and electrolytes on four fullerene nanoparticle suspensions (i.e., C₆₀, C₆₀(OH)₂₄, single- and multiwall carbon nanotubes) were explored with respect to: (1) characteristics of nanoparticle aggregates, (2) transport of the aggregates through a silica porous media, and (3) production of reactive oxygen species (ROS) from the photosensitized fullerene aggregates. The presence of HA and salts increased the size of aggregates and relative hydrophobicity associated with transport through silica beads, while decreasing ROS production. These data illustrate the importance that transformation of engineered nanomaterials (ENMs) through interactions with aquatic solutes may have in altering the environmental behavior of nanomaterials.     

Escherichia coli contamination of the river Thames in different seasons and weather conditions

Contamination of public water ways with sewage represents a serious environmental and health risk. We monitored pollution of the river Thames by enumerating the indicator organism Escherichia coli. Samples were taken from a site in central London near Waterloo Bridge in different seasons. E. coli were quantified using a membrane filtration method, and correlated with the tidal variations of the river and meteorological data on rainfall and temperature. More frequent and severe incidents of pollution occurred in the autumn. Heavy rainfall resulted in sharp peaks of E. coli contamination that implies a potential increase of numbers of pathogenic micro‐organisms. Sixty percent of all samples were found to be in excess of the accepted upper limit of pollution set by European Union (EU) legislation for bathing water. This study demonstrated that frequent sewage pollution of the Thames results in high numbers of E. coli and incidents of detectable levels of pathogenic bacteria demonstrating the need for regular monitoring of bacterial pollution.     

脂肪酸/膨胀珍珠岩/石蜡复合相变材料的制备及其在建筑节能中的应用

采用真空吸附法以膨胀珍珠岩为载体吸附脂肪酸相变材料,然后用石蜡包裹制备了脂肪酸/膨胀珍珠岩/石蜡复合相变材料,并将其掺入砂浆中制备了相变砂浆。DSC及SEM分析表明,脂肪酸进入膨胀珍珠岩微孔后其热性能未受影响,且石蜡的包裹效果良好。相变砂浆的分层度和抗压强度均满足GB/T 20473—2006《建筑保温砂浆》的要求。掺入复合相变材料能有效改善砂浆的热性能,温度最高点的延迟时间达24 min,最大降温幅度达4.5℃。     

Electrochemical disinfection of Escherichia coli in the presence and absence of primary sludge particulates

Electrochemical (EC) residual disinfection of Escherichia coli (E. coli) in the presence and absence of primary sludge particulates (PSPs) was studied. The kinetics followed a first-order rate law. When PSPs were absent, the EC residual disinfection rate coefficient (k) increased linearly with EC pretreatment energy (E_C, 0–0.63 kWh/m³). However, with 143 mg PSPs/L, k first increased linearly with E_C (0–0.28 kWh/m³) and then decreased linearly with E_C (0.28–0.42 kWh/m³). H₂O₂ was detected during EC pretreatment in PSPs-free samples and the H₂O₂ concentration (C_H) increased with E_C (0–0.83 kWh/m³) linearly. Chloride was detected in PSPs aqueous samples (143 mg PSPs/L) and its concentration (C_C) changed during EC pretreatment: initially, a decrease of C_C was observed when E_C increased from 0 to 0.28 kWh/m³, followed by an increase of C_C when E_C increased 0.28–0.42 kWh/m³. In both cases, k correlated to the initial post-EC chloride concentration (C_CI) in an inverse linear relationship. This two-stage change of C_C and k was caused by a combination of two reactions: anodic oxidation of chloride and the reaction of chloramines with excess chlorine. This paper explains the mechanisms underlying EC residual disinfection in the presence and absence of PSPs, and proposes a feasible strategy for EC disinfection when PSPs are present, an approach that could be useful in the treatment of combined sewage overflow (CSO).     

Effect of iron on the sensitivity of hydrogen, acetate, and butyrate metabolism to inhibition by long-chain fatty acids in vegetable-oil-enriched freshwater sediments

Freshwater sediment microbial communities enriched by growth on vegetable oil in the presence of a substoichiometric amount of ferric hydroxide (sufficient to accept about 12% of the vegetable-oil-derived electrons) degrade vegetable oil to methane faster than similar microbial communities that develop when sediments are enriched by growth on vegetable oil in the absence of ferric hydroxide. This study examined the effects of enrichment in the presence of Fe(III) on the fatty-acid sensitivity of several important members of anaerobic triglyceride-degrading microbial communities in freshwater sediments. The fatty-acid sensitivity of three groups of microorganisms-hydrogenotrophic methanogens, acetate consumers, and hydrogen-producing acetogens-were investigated by comparing the rates of hydrogen, acetate, or butyrate consumption in the presence and absence of oleic acid. Methanogenesis from hydrogen was not affected by sediment enrichment conditions or by the presence of oleic acid, suggesting that hydrogenotrophic methanogens were insensitive to fatty acid inhibition in these sediments. Oleic acid inhibited the anaerobic degradation rates of acetate and butyrate by 38% and 63%, respectively, but enrichment in the presence of Fe(III) eliminated the fatty-acid sensitivity of acetate degradation and reduced the sensitivity of butyrate degradation by about half. These results suggest that iron-reducing bacteria may provide an alternative pathway through which vegetable oil can be converted to methane in anaerobic freshwater sediments.     

Durability of a coating containing titanium dioxide for the photocatalytic degradation of diclofenac in water with UV‐A irradiation

A novel catalyst was used for lab scale photocatalytic experiments. It was a carbon doped titanium dioxide which was designed to create an energy efficient photocatalytic process. The titanium dioxide is able to absorb UV‐A radiation and parts of the visible light spectrum. The catalyst was immobilized to a glass sheet. UV‐A radiation was used for the degradation of the pharmaceutical diclofenac in water to investigate the applicability of the catalyst to degrade organic micropollutants. With the given experimental setup hydroxyl radicals were generated and diclofenac was degraded below the limit of quantification. However, reaction rates are rather slow and the material properties of the catalyst showed the need of improvement. This is because the properties of the coating were influenced by the release of inorganic binder. Therefore, the coating and possibly the titanium dioxide were washed off and the reaction rates decreased drastically after 80 hours of use.     

The role of nitrite and free nitrous acid (FNA) in wastewater treatment plants

Nitrite is known to accumulate in wastewater treatment plants (WWTPs) under certain environmental conditions. The protonated form of nitrite, free nitrous acid (FNA), has been found to cause severe inhibition to numerous bioprocesses at WWTPs. However, this inhibitory effect of FNA may possibly be gainfully exploited, such as repressing nitrite oxidizing bacteria (NOB) growth to achieve N removal via the nitrite shortcut. However, the inhibition threshold of FNA to repress NOB (∼0.02 mg HNO₂-N/L) may also inhibit other bioprocesses. This paper reviews the inhibitory effects of FNA on nitrifiers, denitrifiers, anammox bacteria, phosphorus accumulating organisms (PAO), methanogens, and other microorganisms in populations used in WWTPs. The possible inhibition mechanisms of FNA on microorganisms are discussed and compared. It is concluded that a single inhibition mechanism is not sufficient to explain the negative impacts of FNA on microbial metabolisms and that multiple inhibitory effects can be generated from FNA. The review would suggest further research is necessary before the FNA inhibition mechanisms can be more effectively used to optimize WWTP bioprocesses. Perspectives on research directions, how the outcomes may be used to manipulate bioprocesses and the overall implications of FNA on WWTPs are also discussed.     

江苏城市酸雨问题与对策

八十年代以来，随着全球经济的发展和环境的恶化，酸雨问题已成为全球性问题。改革开放以来，随着我国东部沿海地区经济发展和城市化进程的加速，江苏城市酸雨程度不断加重，酸雨问题已成为江苏可持续发展中必须认真重视的制约因子。本文根据有关资料分析了江苏城市酸雨的现状、特点及发展趋势，并就控制和减轻酸雨危害提出了对策建议。     

A Pilot UK Evaluation of a Rapid Defined Substrate Method for Enumeration of Total Coliforms and Escherichia coli in Water

A simple rapid method for determining total coliforms and Escherichia coli in drinking water was evaluated in a preliminary pilot-scale study at three independent laboratories by comparison with the standard membrane filtration technique. No significant difference was found between the two methods.
The method is based on defined substrate technology. It gives confirmed results within 24 h and requires only limited equipment. It was considered particularly suitable for weekend and emergency use and for on-site testing at remote sampling points.     

165例肾移植手术患者CYP3A5基因多态性与他克莫司浓度/剂量相关性研究

目的 探讨165例肾移植患者362次检测他克莫司血药浓度/剂量（C/D）与CYP3A5基因多态性之间的关系,并通过不同基因型来估算给药剂量,为他克莫司个体化给药提供依据.方法 选择应用他克莫司＋吗替麦考酚酯＋强的松三联免疫抑制方案且移植术后维持此方案半年以上的165例肾移植患者.采用聚合酶链反应-限制性酶切法（PCR-RFLP）检测患者CYP3A5基因多态性,比较不同基因型[野生纯合子组（＊1/＊1）、突变型杂合子组（＊1/＊3）及突变型纯合子组（＊3/＊3）]移植患者他克莫司血药C/D的差异.结果 肾移植患者＊3型突变率为77.88%.肾移植患者CYP3A5基因型＊1/＊1型、＊1/＊3型和＊3/＊3型他克莫司血药C/D分别为（40.54±19.98）、（74.76±38.71）和（164.33±96.27）ng·mL-1·mg-1·d·kg,肾移植患者CYP3A5基因型＊1/＊1型的他克莫司血药C/D明显低于＊1/＊3型和＊3/＊3型（P〈0.001,P=0.021）,＊3/＊3型与＊1/＊3型患者之间血药C/D差异无统计学意义（P=0.132）.结论 他克莫司的C/D与CYP3A5基因多态性密切相关.含CYP3A5＊3等位基因的患者与纯野生型患者相比可减少他克莫司的给药剂量.     

Investigating the decay rates of Escherichia coli relative to Vibrio parahemolyticus and Salmonella Typhi in tropical coastal waters

Using the size fractionation method, we measured the decay rates of Escherichia coli, Salmonella Typhi and Vibrio parahaemolyticus in the coastal waters of Peninsular Malaysia. The size fractions were total or unfiltered, <250 μm, <20 μm, <2 μm, <0.7 μm, <0.2 μm and <0.02 μm. We also carried out abiotic (inorganic nutrients) and biotic (bacterial abundance, production and protistan bacterivory) measurements at Port Dickson, Klang and Kuantan. Klang had highest nutrient concentrations whereas both bacterial production and protistan bacterivory rates were highest at Kuantan. We observed signs of protist-bacteria coupling via the following correlations: Protistan bacterivory−Bacterial Production: r = 0.773, df = 11, p < 0.01; Protist−Bacteria: r = 0.586, df = 12, p < 0.05. However none of the bacterial decay rates were correlated with the biotic variables measured. E. coli and Salmonella decay rates were generally higher in the larger fraction (>0.7 μm) than in the smaller fraction (<0.7 μm) suggesting the more important role played by protists. E. coli and Salmonella also decreased in the <0.02 μm fraction and suggested that these non-halophilic bacteria did not survive well in seawater. In contrast, Vibrio grew well in seawater. There was usually an increase in Vibrio after one day incubation. Our results confirmed that decay or loss rates of E. coli did not match that of Vibrio, and also did not correlate with Salmonella decay rates. However E. coli showed persistence where its decay rates were generally lower than Salmonella.     

Evaluation of data from the literature on the transport and survival of Escherichia coli and thermotolerant coliforms in aquifers under saturated conditions

Escherichia coli and thermotolerant coliforms are of major importance as indicators of fecal contamination of water. Due to its negative surface charge and relatively low die-off or inactivation rate coefficient, E. coli is able to travel long distances underground and is therefore also a useful indicator of fecal contamination of groundwater. In this review, the major processes known to determine the underground transport of E. coli (attachment, straining and inactivation) are evaluated. The single collector contact efficiency (SCCE), eta0, one of two parameters commonly used to assess the importance of attachment, can be quantified for E. coli using classical colloid filtration theory. The sticking efficiency, alpha, the second parameter frequently used in determining attachment, varies widely (from 0.003 to almost 1) and mainly depends on charge differences between the surface of the collector and E. coli. Straining can be quantified from geometrical considerations; it is proposed to employ a so-called straining correction parameter, alpha(str). Sticking efficiencies determined from field experiments were lower than those determined under laboratory conditions. We hypothesize that this is due to preferential flow mechanisms, E. coli population heterogeneity, and/or the presence of organic and inorganic compounds in wastewater possibly affecting bacterial attachment characteristics. Of equal importance is the inactivation or die-off of E. coli that is affected by factors like type of bacterial strain, temperature, predation, antagonism, light, soil type, pH, toxic substances, and dissolved oxygen. Modeling transport of E. coli can be separated into three steps: (1) attachment rate coefficients and straining rate coefficients can be calculated from Darcy flow velocity fields or pore water flow velocity fields, calculated SCCE fields, realistic sticking efficiency values and straining correction parameters, (2) together with the inactivation rate coefficient, total rate coefficient fields can be generated, and (3) used as input for modeling the transport of E. coli in existing contaminant transport codes. Areas of future research are manifold and include the effects of typical wastewater characteristics, including high concentrations of organic compounds, on the transport of E. coli and thermotolerant coliforms, and the upscaling of experiments to represent typical field conditions, possibly including preferential flow mechanisms and the aspect of population heterogeneity of E. coli.     

改良型A^2/O工艺在污水处理厂中的应用研究

针对A2/O工艺运行过程中的不足和矛盾,以青岛出口加工区污水处理厂为例,研究了A＋A2/O工艺的同步脱氮除磷效果,并通过现场运营得到了验证;测试结果表明该工艺可达到良好的处理效果,在工程设计和建设中有很好的应用前景。     

R410A与R22在家用空调中的应用比较(2)

本文部分（2）利用Bin参数分析法对R410A与R22空调的全年运行耗电进行计算,采用寿命期气候性能（LCCP）指标对R410A与R22的温室效应总体影响进行考查,同时对R410A与R22空调的生产成本进行比较。结果表明R410A空调由于运行效率高,在使用过程中可以显著节约耗电和运行费用,而且随着原材料价格的上涨和R410A压缩机生产能力的扩大,R410A与R22空调具有相近的生产成本;同时,通过减小温室间接效应以及空调的制冷剂充灌量或泄露量,与R22相比,R410A反而还会有利于降低对气候变暖的影响。     

Gas chromatographic-mass spectrometric method for the determination of bisphenol A and its chlorinated derivatives in urban wastewater

The simultaneous determination of trace amounts of endocrine disruptors such as bisphenol A (BPA) and its monochloro, dichloro, trichloro and tetrachloro derivatives in wastewater has been developed using gas chromatography-mass spectrometry (GC-MS). Compounds were previously extracted from the aqueous samples using a liquid-liquid extraction procedure with a mixture of dichloromethane:carbon tetrachloride (25/75). After extraction, solvent was removed and a silylation step was carried out with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA). The silylated compounds were identified and quantified by GC-MS using an HP1-MS column. The retention times were 6.64 min for BPA silylated, 7.26 min for Cl-BPA silylated, 7.99 min for Cl(2)-BPA silylated, 8.85 min for Cl(3)-BPA silylated and 9.95 min for Cl(4)-BPA silylated. A clean-up is not necessary using SIM mode. Deuterated anthracene (2H(10)-anthracene) was used as an internal standard. The detection limits obtained were 0.3, 0.6, 2.0, 4.5 and 13.0 ng L(-1) for silylated BPA, Cl-BPA, Cl(2)-BPA, Cl(3)-BPA and Cl(4)-BPA, respectively. The proposed method was applied satisfactory to the determination of these chemicals, in different types of wastewater previously spiked with different amounts of these chemicals at concentration levels ranging from 0.01 to 2.50 microg L(-1) for BPA, 0.05-2.50 micro L(-1) for Cl-BPA and 0.05-5.00 microg L(-1) for Cl(2)-BPA, Cl(3)-BPA and Cl(4)-BPA, respectively. The method was validated following standard addition methodology.