Long-term aging of copper added to soils

Aging refers to the processes by which the mobility and bioavailability/toxicity of metals added to soil decline with time. Although long-term aging is a key process that needs to be considered in the risk assessment of metals in field soils, the long-term aging of Cu added to soils has not been studied in detail. In this study, the effects of aging on Cu isotopic exchangeability, total Cu in soil pore water, pore water free Cu2+ activity, and "available" Cu measured by the technique of diffusive gradient in thin film (DGT-Cu) were investigated in 19 European soils at two total Cu concentrations shown to inhibit plant (tomato) growth by 10 and 90%. After addition of Cu, the soils were leached, incubated outdoors, and sampled regularly over a 2-year period. The results showed that when water soluble Cu was added to soils, concentrations of Cu determined by each of the techniques tended to decrease rapidly initially, followed by further decreases at slow rates. Soil pH was a vital factor affecting the aging rate of Cu added to soils. The relatively low solubility products and low isotopic exchangeabilities of Cu in calcareous soils immediately after addition of soluble Cu2+ suggested Cu2+ probably precipitated in these soils as Cu2(OH)2CO3 (malachite) and Cu(OH)2. Isotopic dilution was found to be a robust technique for measuring rates of long-term aging reactions. A semi-mechanistic model was developed to describe the rate and extent of Cu aging across soils as affected by soil pH and other physicochemical parameters. Although not measured directly, it is inferred from soil physicochemical controls on Cu aging that processes of precipitation/nucleation of Cu in soils and hydrolysis of Cu2+ followed by a diffusion process controlled the decrease in Cu availability with time. The model was validated by testing it against field soils with different contamination histories and was found to successfully predict the isotopic exchangeability of Cu added to soils based on two parameters: soil pH and time.     

Oxidation of soybean oil during storage of starch-oil composites

The oxidative deterioration of dry starch-oil composites was investigated by chemical and sensory methods. The composites were stored at 37°C for 63 d, and changes in the hexanal content and odor attributes were monitored. Analysis of the extracted oil showed that the first run through the drum dryer presented higher hexanal concentrations than the subsequent runs. Starch-oil composites from the first run though the drum dryer showed higher metal concentrations and higher odor ratings during storage time than the subsequent runs. There was a significant correlation between odor attributes and hexanal concentration in the first run. Since both the oxidation and the metal content were higher in the first run and decreased in further runs, we concluded that oxidation might have been induced by the presence of metal in the drum dryer. It is likely that during drum drying, the metal drum and knife surfaces became coated with soy oil, reducing both abrasion and metal contact with the product. Since many applications of the starch-oil composite technology require drum drying, it will be necessary to take measures to minimize metal contamination of the product, perhaps by discarding the initial portion of product, which contains the most metal.     

生态建造：教育套餐和环境手册

生态建造是一个关注于传播建成环境中可持续性的需要以及促成可持续性的方式的项目。它针对于两个群体：16-19岁的学生，为他们制作了一个交互式的光盘；建造行业中的专业人员。光盘中提出了这样的问题--你的家和学校有多绿色？它说明了类似于建筑尺度和朝向的设计决策如何影响到建筑在能耗方面的表现和CO2的排放量。光盘包括了衡量如往宅温室节能效果的术语表，来解释它们对建筑的影响。这样学生们就可以对他们自己的学校和家进行评估，并提出怎样的设计可以提高它们的节能效果。如果我们想全球化地实现可持续性的未来，下一代的介入至关重要。环境手册中更深入地研究了这些问题，并关注到了其他建筑类型，如办公建筑。本文描述了正趋于完成的教育光盘和环境手册中涉及的一些根本的环境和教育因素。     

Identification and quantification of anammox bacteria in eight nitrogen removal reactors

Various studies have revealed anaerobic ammonium oxidation (anammox) as a very attractive alternative process suitable for nitrogen removal from wastewater. Here we investigated anammox bacteria in eight different nitrogen removal reactors. The diversity and abundance of anammox bacteria were determined by the 16S rRNA gene analysis, fluorescence in situ hybridization with specific probes and real-time quantitative PCR (qPCR). In these reactors, at least eight unique near full length anammox 16S rRNA gene sequences were detected, which were distributed over two genera; Candidati Brocadia and Kuenenia. FISH results confirmed that only one anammox bacterium dominated the community in each of the eight reactors investigated in this study. qPCR analysis revealed that anammox bacteria were present in seven of the reactors in the order of 10⁹ cells/ml and 10⁷ cells/ml in reactor A1. The dominant and divergent Brocadia-like anammox phylotype in one reactor represented a novel species for which we propose the name Candidatus Brocadia sinica. Taken together, these results indicated that a single seeding source could be used to seed anammox reactors designed to treat different types of wastewater, which could lead to a faster start-up of bioreactors.     

在LTspice/SwitcherCAD Ⅲ中采用变压器

关于LTspice/SwitcherCAD Ⅲ LTspice/SwitcherCAD Ⅲ是一款具集成原理图捕获能力的强大SPICE仿真工具.     

iFlash:80℃活化漂白与新型皂洗

加工技术与设备的发展通常会使加工时间缩短.但是新型助剂的应用也可减少加工时间,大大降低成本.随着iFlash系统的应用,漂白温度可降至80℃,活性染料染色后皂洗的时间也大大缩短.因此,织物间歇式染色得到优化,在不增加额外投资的情况下运行更经济.     

实现无线设计过程的无缝协作

(上篇)在无线系统设计过程中依靠基于部门划分的方法,往往会给开发流程带来麻烦。使用系统级模型不仅可以解决诸多此类问题,而且能够大大改进设计流程。各家公司都在使用基于模型的设计,以整合不同的开发团队(例如,模拟和数字)和各个设计阶段(例如,设计和验证),从而获得巨大收益。     

Vehicle mass and injury risk in two-car crashes: A novel methodology

This paper introduces a novel methodology based on disaggregate analysis of two-car crash data to estimate the partial effects of mass, through the velocity change, on absolute driver injury risk in each of the vehicles involved in the crash when absolute injury risk is defined as the probability of injury when the vehicle is involved in a two-car crash. The novel aspect of the introduced methodology is in providing a solution to the issue of lack of data on the speed of vehicles prior to the crash, which is required to calculate the velocity change, as well as a solution to the issue of lack of information on non-injury two-car crashes in national accident data. These issues have often led to focussing on relative measures of injury risk that are not independent of risk in the colliding cars. Furthermore, the introduced methodology is used to investigate whether there is any effect of vehicle size above and beyond that of mass ratio, and whether there are any effects associated with the gender and age of the drivers. The methodology was used to analyse two-car crashes to investigate the partial effects of vehicle mass and size on absolute driver injury risk. The results confirmed that in a two-car collision, vehicle mass has a protective effect on its own driver injury risk and an aggressive effect on the driver injury risk of the colliding vehicle. The results also confirmed that there is a protective effect of vehicle size above and beyond that of vehicle mass for frontal and front to side collisions.