密相塔半干法烟气脱硫塔内加湿降温及其对脱硫效率的影响

为了实现密相塔半干法脱硫工艺的精确加湿进一步提高系统脱硫效率,利用推导出的传热传质计算方法,得到烟气温度降低和加水量的关系.结合3组密相塔半干法工程实际数据,发现理论计算值和实测值误差区间仅为2.9％ ～5.4％.通过选取河北某钢厂210 m2烧结烟气密相塔半干法脱硫项目实际在线检测数据,发现循环脱硫灰含湿量为3％的系统脱硫效率整体高于含湿量为5％和4％的样品,最大值达93.56％.通过粒度分析、扫描电镜、X射线衍射及差热-热重对2种不同含湿量的循环脱硫灰进行表征,结果表明,含湿量为3％的循环脱硫灰较含湿量为5％的样品粒径小、比表面积大,无团聚现象,物相分析还证实相对于含湿量为5％样品,其Ca(OH)2和结晶水含量少,几乎都是CaSO4和CaS03干态物质,因此脱硫反应进行彻底,脱硫效率较高.     

Biogeochemical cycling of selenium in the San Joaquin Valley,California, USA

Subsurface agricultural drainage waters from western San Joaquin Valley, California, were found to contain elevated concentrations of the element selenium in the form of selenate. In 1978, these drainage waters began to replace previous input to Kesterson Reservoir, a pond system within Kesterson National Wildlife Refuge; this substitution was completed by 1982. In the 1983 nesting season, unusual rates of deformity and death in embryos and hatchlings of wild aquatic birds (up to 64% of eared grebe and American coot nests) occurred at the refuge and were attributed to selenium toxicosis. Features necessary for contamination to have taken place included geologic setting, climate, soil type, availability of imported irrigation water, type of irrigation, and the unique chemical properties of selenium. The mechanisms of biogeochemical cycling raise questions about other ecosystems and human exposure.     

The effects of temperature on decomposition and allelopathic phytotoxicity of boneseed litter

Decomposition of plant litter is a fundamental process in ecosystem function, carbon and nutrient cycling and, by extension, climate change. This study aimed to investigate the role of temperature on the decomposition of water soluble phenolics(WSP), carbon and soil nutrients in conjunction with the phytotoxicity dynamics of Chrysanthemoides monilifera subsp. monilifera(boneseed) litter. Treatments consisted of three factors including decomposition materials(litter alone, litter with soil and soil alone), decomposition periods and temperatures(5–15, 15–25and 25–35°C(night/day)). Leachates were collected on 0, 5, 10, 20, 40 and 60 th days to analyse physico-chemical parameters and phytotoxicity. Water soluble phenolics and dissolved organic carbon(DOC) increased with increasing temperature while nutrients like SO-24 and NO-13 decreased. Speed of germination, hypocotyl and radical length and weight of Lactuca sativa exposed to leachates were decreased with increasing decomposition temperature. All treatment components had significant effects on these parameters. There had a strong correlation between DOC and WSP, and WSP content of the leachates with radical length of test species. This study identified complex interactivity among temperature, WSP, DOC and soil nutrient dynamics of litter occupied soil and that these factors work together to influence phytotoxicity.     

Fingerprinting Global Climate Change and Forest Management Within Rhizosphere Carbon and Nutrient Cycling Processes

As one of the two Principal Subject Editors for ESPR Subject Area 1 'Terrestrial Ecology and Biology / Soil and Sediments: Toxicology-related Subjects' (see pp 287-293), the senior author and his colleague, Dr Chen, present an example of sub-category 4 'Environmental studies of pesticides, air pollution, and management strategies for forestry and plant ecosystems'. Thereby, they inform the ESPR community about the new Australian research project concerning the fingerprints of global climate change (GCC) and forest management on rhizosphere carbon and nutrient cycling and, subsequently, present an overview on the GCC and forest management fingerprints.     

E-bikers’ braking behavior: Results from a naturalistic cycling study

Abstract

Objective: The number of e-bike users has increased significantly over the past few years and with it the associated safety concerns. Because e-bikes are faster than conventional bicycles and more prone to be in conflict with road users, e-bikers may need to perform avoidance maneuvers more frequently. Braking is the most common avoidance maneuver but is also a complex and critical task in emergency situations, because cyclists must reduce speed quickly without losing balance. The aim of this study is to understand the braking strategies of e-bikers in real-world traffic environments and to assess their road safety implications. This article investigates (1) how cyclists on e-bikes use front and rear brakes during routine cycling and (2) whether this behavior changes during unexpected conflicts with other road users.

Methods: Naturalistic data were collected from 6 regular bicycle riders who each rode e-bikes during a period of 2 weeks, for a total of 32.5?h of data. Braking events were identified and characterized through a combined analysis of brake pressure at each wheel, velocity, and longitudinal acceleration. Furthermore, the braking patterns obtained during unexpected events were compared with braking patterns during routine cycling.

Results: In the majority of braking events during routine cycling, cyclists used only one brake at a time, favoring one of the 2 brakes according to a personal pre-established pattern. However, the favored brake varied among cyclists: 66% favored the rear brake and 16% the front brake. Only 16% of the cyclists showed no clear preference, variously using rear brake, front brake, or combined braking (both brakes at the same time), suggesting that the selection of which brake to use depended on the characteristics of the specific scenario experienced by the cyclist rather than on a personal preference. In unexpected conflicts, generally requiring a larger deceleration, combined braking became more prevalent for most of the cyclists; still, when combined braking was not applied, cyclists continued to use the favored brake of routine cycling. Kinematic analysis revealed that, when larger decelerations were required, cyclists more frequently used combined braking instead of single braking.

Conclusions: The results provide new insights into the behavior of cyclists on e-bikes and may provide support in the development of safety measures including guidelines and best practices for optimal brake use. The results may also inform the design of braking systems intended to reduce the complexity of the braking operation.     

生态住宅的水环境规划:I. 水循环

生态住宅已成为住宅建设的发展趋势和潮流,水环境是生态住宅小区的重要组成部分。文章以中信保利达美景度假区为实例,根据度假区建筑总体规划方案,结合当地自然条件和水环境现状,探讨生态住宅小区的水环境规划,全面统一规划住宅小区内各种水系统,提出小区水环境总体规划方案,充分发挥各系统的功能,使其相互衔接、协调与补充。重点对项目所在区域开发前后的水量平衡,水库的水位变化及其安全性,极端气候条件下的库区水量变化及其因应对策,高尔夫球道的用水方案以及项目开发后的水循环模型做了深入探讨,旨在为生态住宅的水环境建设提供范例。     

森林土地利用变化及其对碳循环的影响

由于人口剧增，人类活动的影响不断加大，在过去100年全球土地利用／土地覆被发生了巨大的变化。最常见的土地利用变化是由森林转变为农业用地。森林砍伐使森林生态系统地上部生物量大大减少，砍伐后作农业用地，降低了植被生产力，减少了土壤有机质的输入，增强了腐殖质的矿化作用，有机质分解速率增加，有机碳贮量随之降低，从而影响到森林生态系统的碳循环，使大量碳元素释放到大气中，引起温室效应，导致全球变暖。另一个常见的土地利用变化是植树造林和森林恢复，这一过程可以增加森林生态系统的碳储量，从而减缓大气CO2体积分数的上升。     

基于CESM-EnSRF系统全球甲烷及臭氧卫星资料同化试验研究

臭氧(O3)与甲烷(CH4)均是大气中重要的微量气体,对全球气候变化有着重要的影响.为提高全球范围的臭氧、甲烷在气候模式中的预报效果,使用集合平方根滤波(En SRF)同化方法及地球系统模式(CESM)构建了CESM-En SRF卫星资料同化预报系统,并通过设计试验,将大气红外探测器(AIRS)的臭氧与甲烷观测资料同化到气候模式中,对模式的同化再预报效果进行系统的测试与评估.结果显示,臭氧、甲烷分析集合均值的偏差及均方根误差皆低于背景集合均值的偏差及均方根误差.臭氧、甲烷的同化再预报偏差及均方根误差较控制实验都得到改善,但对5 h Pa以上高度臭氧预报准确性的改进效果很小.随循环同化的进行,平流层臭氧与甲烷的平均同化改进率呈增加趋势,并逐渐趋于稳定;对流层平均同化改进率随时间变化不明显.试验表明,该系统可有效利用臭氧与甲烷的观测资料对模式场进行合理的改善,从而有效地提高臭氧、甲烷在气候模式中的再预报效果,但对于平流层顶-中间层高度(5 h Pa以上)臭氧预报准确度的提高,模式中臭氧光化学过程的准确模拟较同化观测资料具有更重要的作用.此外,循环同化对提高5~150 h Pa高度臭氧及1~200 h Pa高度甲烷在CESM模式中的预报效果最有效.     

Litter decomposition and nitrogen release in a sloping Mediterranean subtropical agroecosystem on the coast of Granada (SE, Spain): Effects of floristic and topographic alteration on the slope

On the coast of Granada (SE, Spain), an economically important area for subtropical fruit cultivation, the crops are grown on orchard terraces. Also, high amounts of fertilizers, often excessive, are used in this type of intensive agriculture. However, each year significant fractions of nutrients taken up by the trees return to the soil by fallen leaves. Using a litter-bag technique, we assessed the decomposition rates and N-release in various types of litter. Our main purpose was to compare two different agroecosystem scenarios: (1) an unaltered slope consisting mainly of a mixture of herbaceous plants (Papaver rhoeas, Convolvulus sp., Malva sylvestris, Reseda phyteuma, Anacyclus sp., Sinapis arvensis, Medicago sp.) among spontaneous perennial woody shrubs (Genista umbellata, Olea europaea, Lavandula officinalis, Phlomis purpurea, Retama sphaerocarpa), and (2) an altered slope cultivated with subtropical trees on terraces: loquat (Eriobotrya japonica), mango (Mangifera indica), avocado (Persea americana), and cherimoya (Annona cherimola), with groundcover plantings of aromatic, medicinal, and melliferous plants (AMMPs) on the taluses of the terraces, which are usually used for erosion control: Lavandula dentata, Thymus mastichina, Satureja obovata, Rosmarinus officinalis, Anthyllis cytisoides. In the leaves from the subtropical crops, we found the highest decomposition rates in cherimoya and the lowest in mango (1.30 and 0.64 years⁻¹, respectively). Leaves from mango and loquat registered initial peaks of N immobilization and later N-release, which was highest in cherimoya and avocado leaves (71.2 and 56.8% of the initial remaining N). In the spontaneous woody shrubs, O. europaea and G. umbellata were the slowest in decomposing (1.18 and 1.01 years⁻¹, respectively) contrary to L. officinalis, which decomposed fastest (2.22 years⁻¹). Only L. officinalis and P. purpurea registered a net N-release at the end of the study. The AMMPs showed different decomposition patterns: L. dentata registered the highest decomposition rates and Rosmarinus the lowest (1.9 and 1.1 years⁻¹, respectively). T. mastichina, L. dentata, and S. obovata had the highest N-release, whereas R. officinalis and A. cytisoides showed N immobilization (183 and 122% of the initial N). Knowledge of the dynamics of nutrient release and litter decomposition will be useful for predicting nutrient availability and nutrient cycles in these types of agroecosystems where subtropical orchards are grown on terraces.     

基于固定化氮循环细菌技术的镇江金山湖生态工程效果研究

通过细菌筛选、载体分析、固定化氮循环菌制备,获取了高效固定化氮循环细菌;采用固定化氮循环细菌技术对镇江金山湖富营养化水体进行了治理研究.结果表明,经过固定化氮循环细菌释放试验,金山湖示范工程区水体和水生植物根区氨化细菌、亚硝化细菌、硝化细菌和反硝化细菌数量明显增加,重建的金山湖示范工程区水体水质明显改善,TN、NH⁺₄-N、NO^-₃-N和NO^-₂-N平均比示范工程前分别降低44.70％、 67.17％、 31.79％和74.21％,氨氮达到Ⅱ类、总氮达到Ⅳ类水标准.固定化氮循环细菌技术对于荒漠化水体生态重建与修复具有重要意义.