A cantilever array-based artificial nose

We present quantitative and qualitative detection of analyte vapors using a microfabricated silicon cantilever array. To observe transduction of physical and chemical processes into nanomechanical motion of the cantilever, swelling of a polymer layer on the cantilever is monitored during exposure to the analyte. This motion is tracked by a beam-deflection technique using a time multiplexing scheme. The response pattern of eight cantilevers is analyzed via principal component analysis (PCA) and artificial neural network (ANN) techniques, which facilitates the application of the device as an artificial chemical nose. Analytes tested comprise chemical solvents, a homologous series of primary alcohols, and natural flavors. First differential measurements of surface stress change due to protein adsorption on a cantilever array are shown using a liquid cell.     

Effect of an enhanced natural radioactivity on mammal fertility

Male and female mice of the BALB/c strain were placed on the floor of a hut built at a site of the Permian Basin of Lodève (Southwest France) where the dose rate of γ radiation amounts to about 10 mrad/h. In previous experiments such high natural radioactivity was shown to induce point mutations in plant material as well as chromosome aberrations in somatic cells of experimental mammals. Controls were kept near the radioactive site under comparable conditions. After the exposure period, the animals were mated in our laboratory, with control mice of the same strain.Due to the high radiosensitivity of mouse oocytes, the fertility of the exposed females was drastically reduced in spite of the fact that the dose received did not exceed 13.8 rad. The fertility of the males exposed to 13 rad, 15 rad or to 45 rad was increased above the control values but was reduced for the animals receiving 63 rad. Analysis of the results show that the differences in fertility are mainly due to a decrease in the number of sterile pairs when males have been exposed to doses upto 45 rad and to an inverse effect when animals received 63 rad. Since histology and weight of the testes suggest that the germ cell population was normal, one has to conclude that the variations in fertility result from physiological effects.     

Chloridazon-Metaboliten im Grundwasser

Grundwasser - Chloridazon ist ein Herbizidwirkstoff, der in Deutschland seit 1964 für den Einsatz in der Landwirtschaft zugelassen ist. Er wird hauptsächlich beim Anbau von Rüben,...     

Allergy and respiratory health effects of dampness and dampness‐related agents in schools and homes: a cross‐sectional study in Danish pupils

Little is known about the health effects of school‐related indoor dampness and microbial exposures. In this study, we investigated dampness and dampness‐related agents in both homes and schools and their association with allergy and respiratory health effects in 330 Danish pupils. Classroom dampness was identified based on technical inspection and bedroom dampness on parents' self‐report. Classroom and bedroom dust was analyzed for seven microbial components. Skin prick testing determined atopic sensitization. Lung function was expressed as z‐scores for forced expiratory volume in one‐second (zFEV₁), forced vital capacity (zFVC) and the ratio zFEV₁/zFVC using GLI‐2012 prediction equations. The parents reported children's allergies, airway symptoms, and doctor‐diagnosed asthma. High classroom dampness, but not bedroom dampness, was negatively associated with zFEV₁ (β‐coef. ?0.71; 95% CI ?1.17 to ?0.23) and zFVC (β‐coef. ?0.52; 95% CI ?0.98 to ?0.06) and positively with wheezing (OR 8.09; 95% CI 1.49 to 43.97). No consistent findings were found between any individual microbial components or combination of microbial components and health outcomes. Among other indoor risk factors, environmental tobacco smoke (ETS) decreased zFEV₁ (β‐coef. ?0.22; 95% CI ?0.42 to ?0.02) and zFEV₁/zFVCratio (β‐coef. ?0.26; 95% CI ?0.44 to ?0.07) and increased upper airway symptoms (OR 1.66; 95% CI 1.03–2.66). In conclusion, dampness in classrooms may have adverse respiratory health effects in pupils, but microbial agents responsible for this effect remain unknown.     

威尼斯与鹿特丹：潮汐之城的潟湖与三角洲景观

沿海和三角洲地区持续面对潮汛引发的洪水、冲淤失衡等挑战。以威尼斯潟湖与鹿特丹三角洲为例,探讨和寻找了此类地区长期存续的发展方式。调研两城的城水关系发展,关注不同时期冲淤变化及其对城市区位和空间结构的影响,考虑当前和未来影响冲淤平衡的可能性,得出3个结论：1）更好地顺应自然趋势和利用区域水系统的变化,增强城市化景观的韧性并且从根本上修复生态系统,此目标达成的关键是恢复区域水系统稳定的冲淤平衡;2）上述根本性改变的前提是港口经济和航运业的彻底重组;3）城水关系发展历史表明潟湖、三角洲和河口不同的自然系统在城市中发挥作用的方式存在差异。对城水关系演变的关注可令公众强烈意识到冲淤平衡稳定对城市景观的重要性,研究经验可供其他河口、三角洲或潟湖城市借鉴。     

可持续之美,外观的性能——宣言之二

一般来说,要理解可持续性景观设计,可以从它与生态健康、社会公正以及经济繁荣3个基本要素之间的关系来着手.但在关于可持续性的讨论中,美学方面的要素鲜被提及,或者反过来,认为将视觉与审美融合对可持续和审美都是多余、无益的.主要考察美(beauty)与美学(aesthetics)在可持续性的各方面所起到的作用.除了生态修复设计外,要使得文化可持续,还需要许多别的作为.我们需要的是具有启示性的景观设计:让体验过如此景观的人能够更深刻地体会到他们的行为是如何影响环境的,而对环境足够的关切则能改善环境.这就需要考虑到“审美的环境体验”(aesthetic environmental experiences)的作用,例如对“美”的感知,应当更加倾向于“生物中心主义(bio-centric)”,而不是“个人中心主义(egocentric)”.受到美国风景园林师设计的许多作品的激发,把这种观点以宣言的形式表达出来,虽然这些作品通常并不被认为对生态设计有所贡献.     

Ca15(CBN)6(C2)2O- a new cubic structure type containing CBN-anions together with acetylide and oxo anions

Ca₁₅(CBN)₆(C₂)₂O contains CBN⁴⁻ anions as well as C₂⁻ units and isolated O²⁻ anions. The compound is obtained by heating a stoichiometric mixture of CaO, C and BN with an excess of Ca in sealed niobium ampoules to 1270 K. It crystallizes in the space group Ia d with a = 1656.84(9) pm. Preparation, crystal structure, NMR and IR-spectroscopic properties are discussed.     

混凝土与可持续发展

从可持续发展的角度指出：混凝土可持续发展最有效的途径是尽可能少地使用波特兰水泥;多用回收废旧材料,尽可能少地消耗自然资源;提出了混凝土可持续发展的若干构想.     

Thermodynamic analysis and performance optimization of organic rankine cycles for the conversion of low‐to‐moderate grade geothermal heat

The present study considers a thermodynamic analysis and performance optimization of geothermal power cycles. The proposed binary‐cycles operate with moderately low temperature and liquid‐dominated geothermal resources in the range of 110°C to 160°C, and cooling air at ambient conditions of 25°C and 101.3 kPa reference temperature and atmospheric pressure, respectively. A thermodynamic optimization process and an irreversibility analysis were performed to maximize the power output while minimizing the overall exergy destruction and improving the First‐law and Second‐law efficiencies of the cycle. Maximum net power output was observed to increase exponentially with the geothermal resource temperature to yield 16–49 kW per unit mass flow rate of the geothermal fluid for the non‐regenerative organic Rankine cycles (ORCs), as compared with 8–34 kW for the regenerative cycles. The cycle First‐law efficiency was determined in the range of 8–15% for the investigated geothermal binary power cycles. Maximum Second‐law efficiency of approximately 56% was achieved by the ORC with an internal heat exchanger. In addition, a performance analysis of selected pure organic fluids such as R123, R152a, isobutane and n‐pentane, with boiling points in the range of ?24°C to 36°C, was conducted under saturation temperature and subcritical pressure operating conditions of the turbine. Organic fluids with higher boiling point temperature, such as n‐pentane, were recommended for non‐regenerative cycles. The regenerative ORCs, however, require organic fluids with lower vapour specific heat capacity (i.e. isobutane) for an optimal operation of the binary‐cycle. Copyright © 2015 John Wiley & Sons, Ltd.     

A performance comparison between an air‐source and a ground‐source reversible heat pump

In this study, the performance of a reversible ground‐source heat pump coupled to a municipality water reticulation system, is compared experimentally and with simulations to a conventional air‐source heat pump for space cooling and heating. A typical municipality water reticulation system comprises hundreds of kilometres of pipes designed in loops that will ensure adequate circulation of water. This results in a substantial heat exchanger with great potential. Indirect heat transfer occurs between the refrigerant and ground via the municipality water reticulation system that acts as the water‐to‐ground heat exchanger. The experimental and simulated comparisons of the ground‐source system to the air‐source system are conducted in both the cooling and the heating cycles. Climatalogical statistics are used to calculate the capacities and coefficients of performance of the ground‐source and air‐source heat pumps. Results obtained from measurements and simulations indicate that the utilization of municipality water reticulation systems as a heat source/sink is a viable method of optimizing energy usage in the air conditioning industry, especially when used in the heating mode. Copyright © 2001 John Wiley & Sons, Ltd.