Hydroclimatic variability drives episodic expansion of a floating peat mat in a North American kettlehole basin

The coming century is predicted to feature enhanced climatic variability, including increased frequency, intensity, and duration of extreme climatic events. Ecologists are faced with the critical challenge of anticipating potentially nonlinear ecosystem responses to these changes. High-resolution paleoecological data sets that capture past ecosystem responses to climate variability provide valuable long-term perspectives on the sensitivity of ecosystems to climate-forced state shifts. We used a suite of paleoecological analyses at Titus Bog in northwestern Pennsylvania, USA, to test the hypothesis that the development and expansion of floating peatlands in kettlehole basins represents a threshold response to hydroclimate variability. In contrast with expectations of gradual autogenic peat mat expansion, our results indicate that peat mat expansion at Titus Bog was highly episodic and occurred in three distinct pulses centered on 800, 650, and 400 cal yr BP. Each of these expansion events coincided with or immediately followed decadal-to-mutlidecadal droughts recorded in regional paleoclimate reconstructions. These patterns indicate that peatland development in kettlehole basins can follow nonlinear trajectories, with episodes of rapid advancement triggered by climatic forcing. Future climate changes may increase the likelihood of peatland expansion in kettlehole basins, potentially leading to abrupt changes in adjacent lake ecosystems.     

An overview on the production of pigment grade titania from titania-rich slag.

To recover pigment grade TiO2, operating plants all over the world use chemical processes. Slag-based technology is considered to be attractive because of low waste generation and low chemical cost due to high titanium content and is poised to replace the conventional technology. This paper provides a review of the slag-based technology with the specific aim to produce leachable slag and achieving high titania yield from recovered wastes. Leachable oxides of the lower oxidation state, such as TiO and Ti2O3, facilitate the leaching process. However, during smelting these oxides increase the viscosity of the slag. Formation of titanium carbide or carbonitride is also not desirable as it leads to resistance to the leaching of titanium. This report highlights the problems and their possible solutions to obtain leachable slag.     

Reforming the CDM for sustainable development: lessons learned and policy futures

The Clean Development Mechanism (CDM) has successfully demonstrated that market-based mechanisms can achieve some cost effective emissions reductions in developing countries. However the distribution of CDM projects has been extremely uneven across countries and regions, and a few technologies and sectors have dominated the early stages of CDM experience. This has caused some to question whether the CDM has fallen short of its potential in contributing to sustainable development. We review the broad patterns of CDM project approvals and evaluate 10 CDM projects according to their sustainability benefits. The difficulty of defining “sustainable development” and the process of defining criteria by individual non-Annex 1 governments has meant that sustainable development concerns have been marginalized in some countries. Given these observed limitations, we present possible CDM policy futures, focusing on the main proposals for a post-2012 climate regime. Five options for enhancing the sustainable development benefits in the CDM are discussed, including proactive approaches to favour eligibility of emission reduction projects which ensure such co-benefits.     

气象模拟误差对异戊二烯排放估算的影响

利用MEGAN模式估算了珠三角地区2006年异戊二烯的排放情况,并设计了两组敏感性实验深入探讨了气象模拟误差对异戊二烯排放的影响.估算结果显示,2006年珠三角地区异戊二烯的排放量为95.56×106kg(以C计),且主要分布在珠三角地区周边植被覆盖较高的地方;受气象条件季节变化的影响,异戊二烯的排放表现出显著的季节和日变化特征,最大异戊二烯排放通量季节出现在夏季,为0.920t·km-2(以C计),最大排放速率均出现在13:00.敏感性实验结果显示,气象模拟误差能显著影响异戊二烯的排放,升高(降低)太阳辐射的输入,异戊二烯的排放量增加(减小)36.20%～50.70%(30.73%～41.88%),大于温度改变引起的排放量变化;升高(降低)气象输入并不会改变异戊二烯排放的日变化特征,但能显著影响排放速率的大小.上午8:00或下午17:00,异戊二烯排放速率的改变最为明显.     

Male behaviors reveal multiple pherotypes within vine mealybug Planococcus ficus (Signoret) (Hemiptera; Pseudococcidae) populations

The vine mealybug (VM) females collected in Israel produce two sex pheromone compounds: lavandulyl senecioate (LS) and (S)-lavandulyl isovalerate (LI). The males display ambiguous behavior to LI: repulsion in the vineyard and attraction of laboratory-reared males. We addressed the question of individual male behavior, i.e., do males respond to both LS and LI, or might they display a distinct response to each of the two pheromone compounds. We compared male pherotype frequencies between wild-caught and laboratory-reared populations. Then, we examined the relationship between pherotype composition and male capture rates in pheromone traps. Finally, we addressed the heredity of the pherotypes. The Israeli VM populations contain nine different male pherotypes, as defined according to the male behavior to pheromone compounds. The studied Portuguese populations included five of the nine pherotypes; none of the Portuguese males were attracted to LI. It seems that the high frequency of males that were attracted to LI is related to dense VM populations. It is hypothesized that selection for the male pherotypes, I males, those that respond to LI, occur under high-density rearing conditions. This may result from shorter development times of males and females that produce more I male pherotypes. The lower relative frequency of trapping of males in LI-baited traps than expected from the percentage determined in a Petri dish arena suggests that males that respond solely to LS (S males) are better fliers. The results also suggest that the pherotype trait is inherited by both sexes of the VM.     

A hybrid process for manufacturing surgical-grade knife blade cutting edges from bulk metallic glass

The demand for precision surgical knives is enormous. Currently, diamond knives have been the preferred choice among surgeons for use in precision surgeries, owing to the extreme hardness of diamond and the sharpness that can be achieved in single crystal diamond blades, but material and processing costs are high. Bulk metallic glass (BMG) has the potential to be an economically viable material of similar performance for use in precision surgical knives. To this end, a novel hybrid manufacturing process integrating thermally assisted micro-molding and micro-drawing has been developed for producing BMG surgical-grade knife blade cutting edges with edge radii <50 nm. A hybrid process testbed was designed and used to successfully run tests over a range of the key process variables. Through this testing the deformation of BMG under different strain rates and temperatures was studied in terms of the quality of edge formation. The hybrid process was shown to be capable of producing cutting edges of radius at or below 100 nm.     

The effects of surfactant formulation on nonequilibrium NAPL solubilization

Surfactant-enhanced aquifer remediation (SEAR) involves the injection of surfactant solutions into aquifers contaminated with nonaqueous phase liquids (NAPL). Batch and column experiments were used to assess the effect of surfactant formulation on the rate of NAPL solubilization. The experimental variables were surfactant type, surfactant concentration, electrolyte concentration, and cosolvent concentration. Model equations were proposed and solved to describe solubilization under the conditions of each type of experiment. Using these models, a solubilization rate constant, kappa(b), and an overall mass transfer rate coefficient, kappa, were estimated from the batch and column experiments, respectively. The solubilization rate constant was consistently sensitive to surfactant type, surfactant concentration, and electrolyte concentration. The estimated solubilization rate constants varied over two orders of magnitude. The results of the column experiments also were sensitive to the surfactant formulation. Variations in the fitted mass transfer rate coefficient parameter, beta(0), were related to variations in the surfactant formulations. A comparison between the results of the batch and column experiments yields an apparent relationship between beta(0) and kappa(b). This relationship suggests that the mass transfer rate coefficient is directly related to the formulation of the surfactant solution.     

Accounting for Cadmium: Tracking Emissions of Cadmium From the Global Economy

This paper examines the flow of cadmium through the global economy, with the aim of quantifying emissions of cadmium into the environment as a result of anthropogenic activities. First, a materials balance methodology is presented as the most appropriate means of assessing cadmium emissions from a wide range of anthropogenic sources. This is then applied to the best available data, from a variety of sources, to arrive at estimated flows of cadmium. Results are presented for 10 geo-political world regions and for a range of economic activities including non-ferrous metals production, iron and steel production, combustion of fossil fuels, fertilizer manufacture and use, cement production and the manufacture, use and disposal of cadmium containing products. Initially, this analysis partitions the total flow of cadmium into three major categories: atmospheric emissions, water-borne effluents and solid or bulked waste arisings. the paper then suggests a probable further partition of the initial emissions into different environmental media.     

An approach to simulate wind fields around an urban environment for wind energy application

This work proposes an approach to simulate wind flow fields around an urban environment with the aim of evaluating the potential impact of buildings on the general wind patterns and power production using the current generation of commercial wind turbines. The simulation process was performed with the aid of accessible computational tools that can potentially render the proposed procedure applicable in other cases of interest. The roughness of the urban environment was defined as the association of roughness map, topography, and an alternative process for obtaining the volumetry of buildings. A case study was conducted in a region located at the district of Boa Viagem (Recife-PE) for assessing the applicability of the approach. Scenarios were designed in order to simulate wind flow patterns and pre-identify sites that have suitable wind energy potential for electric power production by investigating the combination of wind speed magnitude and turbulence intensity. From the results obtained, it was possible to identify zones of potential wind sources that are not detected in classical wind atlas probably due to the influence of the built environment on local wind flow patterns.