三个机场候机厅的火灾安全分区评述

通过参观机场对公众开放的区域,对三个机场侯机厅的火灾安全分区进行了评述,这三个机场是,香港的旧启德机场,澳大利亚的悉尼机场和墨尔本机场,指出了一般的被动建筑设计和积极的火灾防护系统,按照估计的火灾载葆密度对零售区域商店的形状和商品进行了记录,利用消防工程计算程序FIRECALC对三种水喷头的启动时间进行了预测。     

Pilot scale field test for compostable packaging materials in the City of Kassel, Germany

Biodegradable (compostable) packaging materials made from biopolymers (BP) are introduced into the market to reduce the amounts of conventional packaging materials and at the same time be recovered by the municipal organic waste collection system. The processing of this organic waste mixed with biopolymers has been tested in a commercial treatment facility. The safe use of the compost produced from these materials was demonstrated in a full-scale agricultural application test.     

Adsorption of PCDD/F on MWI fly ash

The removal of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) from waste incinerator off-gas is a costly task, because a considerable part of the PCDD/F may exist in the gas phase (often 50-100% around 200 degrees C). The volatile fraction passes the particle filter and the subsequent gas cleaning equipment, so that an additional unit is needed to remove the gaseous PCDD/F from the flue gas. Moreover, dioxins and furans can accumulate in some parts of the equipment in a way that they can act as a latent source. In this work, we investigate the possibility to adsorb the PCDD/F at the fly ash particles and to remove them during the filtration. The gas/particle partitioning of the PCDD/F depends on the temperature, the vapor pressure, the particle size, the particle number density and on the physical and chemical properties of the particle surface. These relationships are investigated by model calculations and by pilot scale experiments (500 Nm3/h) which employ one selected hexachlorinated dioxin congener. At room temperature, approx. 90% of the HxCDD are found in the particulate phase, while at 135 degrees C that portion is only 10%. This means that at ambient temperatures, the gas/particle partitioning of the dioxin corresponds well to the sublimation equilibrium. At higher temperatures, it is much different from the sublimation equilibrium and the apparent adsorption enthalpy is smaller than the enthalpy of sublimation. This observation is in agreement with literature data. From the above experiments and from similar literature data, the efficiency of fly ash particles as a sink for PCDD/F can be evaluated. The data suggest that the adsorption rate is not the limiting factor for the transfer into the particulate phase. The important factors appear to be the chemical composition of the fly ash and the temperature.     

Aromatized arborane/fernane hydrocarbons as biomarkers for cordaites

Previous palaeobotanical and palynological studies on coals from Euramerican Pennsylvanian (≡ Late Carboniferous) coal basins indicate a major change in coal-swamp floras, especially at the Westphalian–Stephanian (≈Kasimovian–Gzhelian, according to Geological Time Scale 2004) boundary. A flora dominated by arborescent lycophytes was replaced by a vegetation dominated by marattialean tree ferns in various Euramerican coal basins. Earlier combined palynological and organic geochemical studies on Westphalian/Stephanian coals and shales from the Saar-Nahe Basin (Germany) revealed that the distribution of aromatized arborane/fernane hydrocarbons in solvent extracts reflects the increasing importance of seed plants, especially cordaites (extinct group of gymnosperms), conifers and pteridosperms. However, the biological source of the precursor molecules could not be specified. To clarify if the arborane/fernane derivatives MATH, MAPH, DAPH 1, and DAPH 2 in Westphalian/Stephanian coals can be assigned to one of the three potential source plant groups, we analyzed coals, sediments and fossil plant remains from different Euramerican locations with respect to their biomarker composition and stable carbon isotopic composition. Thereby, stable carbon isotopic ratios showed only insignificant variations between Westphalian and Stephanian samples and proved to be an unsuitable tool to describe floral changes during the Westphalian/Stephanian of the Saar-Nahe Basin. In contrast, we were able to show for the first time that MATH, MAPH, DAPH 1 and DAPH 2 are prominent constituents only in extracts of cordaitean macrofossils and can therefore be regarded as biomarkers for this group of gymnosperms.     

High survival in poor years: life history tactics adapted to mast seeding in the edible dormouse

Edible dormice (Glis glis) reproduce in years with beech mast seeding, but entire populations may skip reproduction in years when tree seeds, a major food resource of this small hibernator, are absent. We tested the hypothesis that the year-to-year variability in reproductive effort caused by this breeding strategy should lead to detectable differences in yearly survival rates. Therefore, we analyzed capture-recapture data from animals occupying nest boxes, collected over nine years at two study sites in Germany. Among fully grown adults (aged two years or older), survival probabilities were significantly lower (0.32 +/- 0.04) after reproductive years (n = 5) compared to years (n = 4) with absent or below-average reproduction (0.58 +/- 0.07) on both study sites. This trade-off between reproduction and subsequent survival was observed in both females and males and appears to be a relatively rare case in which costs of reproduction in terms of longevity are detectable at the population level. Effects of reproduction on survival were less pronounced when yearlings (with a generally lower reproductive effort) were included and were more distinct in a suboptimal habitat. Of those females breeding in nest boxes, 96.5% had only one or two litters within the study period. Considering these and previously published results, including a report of extremely high mean longevities (9-12 years) of dormice in a habitat with infrequent mast seeding, we conclude that edible dormice flexibly adjust life history tactics to local mast patterns. Long stretches of mast failures can in fact lead to relative semelparity, i.e., a strategy in which dormice "sit tight" for several years until environmental conditions are favorable for reproduction.     

Estimating biodegradation half-lives for use in chemical screening

Biodegradation half-lives are needed for many applications in chemical screening, but these data are not available for most chemicals. To address this, in phase one of this work we correlated the much more abundant ready and inherent biodegradation test data with measured half-lives for water and soil. In phase two, we explored the utility of the BIOWIN™ models (in EPI Suite™) and molecular fragments for predicting half-lives. BIOWIN™ model output was correlated directly with measured half-lives, and new models were developed by re-regressing the BIOWIN™ fragments against the half-lives. All of these approaches gave the best results when used for binary (fast/slow) classification of half-lives, with accuracy generally in the 70–80% range. In the last phase, we used the collected half-life data to examine the default half-lives assigned by EPI Suite™ and the PBT Profiler™ for use as input to their level III multimedia models. It is concluded that estimated half-lives should not be used for purposes other than binning or prioritizing chemicals unless accuracy improves significantly.     

QSPR study on soil sorption coefficient for persistent organic pollutants

Quantitative structure-property relationship (QSPR) models of soil sorption coefficients for 32 persistent organic pollutants were constructed using our recently introduced Lu index and novel distance-based atom-type DAI topological indices. Using multiple linear regression technique, a 6-variable model was obtained with the correlation coefficient of estimations (R) being 0.95, and the standard error of estimations (s) being 0.23, and the correlation coefficient (R(cv)) and the standard error (s(cv)) in the leave-4-out cross-validation procedure are 0.90 and 0.31, respectively. The results in this study indicate that soil sorption coefficients of POPs are dominated by molecular size while some DAI indices have smaller influence.     

Phenanthrene adsorption by soils treated with humic substances under different pH and temperature conditions

The mobility of phenanthrene (PHE) in soils depends on its sorption and is influenced by either the existing soil humus or exogenous humic substances. Exogenous humic acids (HAs) were added to soil to enhance the amount of soil organic carbon (SOC) by 2.5, 5.0, and 10.0 g kg⁻¹. PHE desorption of the treated soils was determined at two pH levels (3.0 and 6.0) and temperatures (15 and 25 °C). Soil PHE adsorption was related to pH and the type and quantity of added HAs. Humic acid (HA) and fulvic acid (FA) derived from peat had different effects on adsorption of PHE. Adsorption increased at first and then decreased with increasing quantity of exogenous FA. When the soil solution pH (in 0.005 M CaCl₂) was 4.5 or 3.0, the turning points were 2.5 g FA kg⁻¹ at pH 3.0 and 5 g FA kg⁻¹ at pH 4.5. When soil solution pH was 6, the amount of adsorbed PHE was enhanced with increasing exogenous HAs (HA or FA) and amount of adsorption by soil treated with FA was higher than with HA. Adsorption of PHE in the FA treatment at 10.0 g kg⁻¹ was lower than the controls (untreated soil or treatment with HAs at 0 g kg⁻¹) when the soil solution pH was 3.0. This suggests that FA adsorbed by soil was desorbed at low pH and would then increase PHE solubility, and PHE then combined with FA. PHE adsorption was usually higher under lower pH and/or lower temperature conditions. PHE sorption fitted the Freundlich isotherm, indicating that exogenous humic substances influenced adsorption of phenanthrene, which in turn was affected by environmental conditions such as pH and temperature. Thus, exogenous humic substances can be used to control the mobility of soil PAHs under appropriate conditions to decrease PAH contamination.     

The Arctic in an earth system context: from brake to accelerator of change

Human activities over the past few centuries have profoundly changed the functioning of the earth system as a whole. These changes are particularly evident in the high latitudes of the Northern Hemisphere, where environmental change has been pronounced and rapid. Such changes have implications beyond the region, as they can lead to two important feedback processes: the ice-albedo feedback and the terrestrial carbon cycle-climate feedback. These processes play an exceptionally important role in earth system functioning, particularly because they may switch this century from damping the effects of anthropogenic climate change to accelerating them. Rapid environmental change in the high latitudes also has consequences for issues of direct importance to humans, particularly water resources.     

Adsorption of molybdate and tetrathiomolybdate onto pyrite and goethite: effect of pH and competitive anions

The adsorption of two major molybdenum (Mo) species, molybdate (MoO4(2-)) and tetrathiomolybdate (MoS4(2-)) onto two main iron minerals pyrite (FeS2) and goethite (FeOOH) is addressed to elucidate the possible mechanisms of molybdenum immobilization in anoxic sediments. Suspensions of MoS4(2-) (or MoO4(2-)) and goethite (or pyrite) in 0.1M NaCl solution were equilibrated under anoxic conditions at 25 degrees C in the pH range from 3 to 10. The competitive effects of sulfate, phosphate, and silicate on the adsorption of MoO4(2-) and MoS4(2-) by pyrite and goethite are also addressed. Adsorption of MoO4(2-) and MoS4(2-) on pyrite and goethite is in general well described by a Langmuir model at low pH; the extent of sorption is a function of pH and the surface loading. Maximum sorption is observed in the acidic pH range (pH<5) at low surface loading. The adsorption of molybdenum (micromol g(-1)) depends upon Mo species and on the type of iron mineral following the order: MoS4(2-)-goethite > MoO4(2-)-goethite > MoS4(2-)-pyrite > MoO4(2-)-pyrite. Phosphate appears to compete strongly with MoO4(2-) and MoS4(2-) for the sorption sites of pyrite and goethite. The strength of the phosphate competitive effect follows the sequence of MoO4(2-)-goethite approximately = MoO4(2-)-pyrite > MoS4(2-)-pyrite > MoS4(2-)-goethite. Silicate and sulfate have a negligible effect on the sorption of MoO4(2-) and MoS4(2-). The preferred adsorption by iron mineral of MoS4(2-), as well as its behavior in the presence of competitive anions suggests that tetrathiomolybdate species may be an ultimate reservoir and may control Mo enrichment in the sediments.