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排序方式: 共有635条查询结果,搜索用时 18 毫秒
491.
Landfills at various stages of development, depending on their age and location, can be found throughout Europe. The type of facilities goes from uncontrolled dumpsites to highly engineered facilities with leachate and gas management. In addition, some landfills are designed to receive untreated waste, while others can receive incineration residues (MSWI) or residues after mechanical biological treatment (MBT). Dimension, type and duration of the emissions from landfills depend on the quality of the disposed waste, the technical design, and the location of the landfill. Environmental impacts are produced by the leachate (heavy metals, organic loading), emissions into the air (CH(4), hydrocarbons, halogenated hydrocarbons) and from the energy or fuel requirements for the operation of the landfill (SO(2) and NO(x) from the production of electricity from fossil fuels). To include landfilling in an life-cycle assessment (LCA) approach entails several methodological questions (multi-input process, site-specific influence, time dependency). Additionally, no experiences are available with regard to mid-term behaviour (decades) for the relatively new types of landfill (MBT landfill, landfill for residues from MSWI). The present paper focuses on two main issues concerning modelling of landfills in LCA: Firstly, it is an acknowledged fact that emissions from landfills may prevail for a very long time, often thousands of years or longer. The choice of time frame in the LCA of landfilling may therefore clearly affect the results. Secondly, the reliability of results obtained through a life-cycle assessment depends on the availability and quality of Life Cycle Inventory (LCI) data. Therefore the choice of the general approach, using multi-input inventory tool versus empirical results, may also influence the results. In this paper the different approaches concerning time horizon and LCI will be introduced and discussed. In the application of empirical results, the presence of data gaps may limit the inclusion of several impact categories and therefore affect the results obtained by the study. For this reason, every effort has been made to provide high-quality empirical LCI data for landfills in Central Europe. 相似文献
492.
Claudia Coral Wolfgang Bokelmann Robert Carcamo Stefan Sieber 《Journal of Land Use Science》2020,15(4):547-569
ABSTRACT Although life and land decisions are individual, driven by perceptions of reality, they reflect broader social processes. This research aims to understand relevant land-use change processes and the context within which land-use change occurs in the study area. For this, we employ grounded theory techniques and procedures to analyze narratives and life history interviews. Based on these narratives, we re-construct past land-use changes. Additionally, we identify structural conditions that drive change, several dimensions of change, including cultural-cognitive dimensions, and future discourses. The identified structural conditions motivate changes in concepts, actions, and practices, in land-use, and institutions, eventually leading to generational changes. Further research is needed to examine how the so-called structural conditions producing change varies in different settings and contexts. These findings can provide insight into certain patterns and knowledge that may contribute to community planning, policy design, and the conception of sustainable solutions with more grounded knowledge. 相似文献
493.
Stefan R. Falke Rudolf B. Husar Bret A. Schichtel 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1579-1585
ABSTRACT Spaceborne sensors allow near-continuous aerosol monitoring throughout the world. This paper illustrates the fusion of Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and TOMS satellite data with surface observations and topographic data during four extreme aerosol events: (1) the April 1998 Asian dust storm that impacted the west coast of North America, (2) the May 1998 Central American forest fire smoke that impacted eastern North America, (3) the intense fall 1999 northern California fires, and (4) the massive February 2000 Sahara dust storm. During these dust and smoke events, the aerosol was visualized on true color SeaWiFS images as a distinct yellowish dye, the result of the aerosol increasing the reflectance of darker surfaces (ocean and land) and decreasing the reflectance of clouds. TOMS imagery also indicated increased aerosol absorption in the affected areas, while surface monitors measured major reductions in visual range. Fusing these data aids in the determination of the aerosol's spatial, temporal, and optical properties and provides supporting evidence for characterizing what is being visualized as dust or smoke. A 3-dimensional perspective of the events is obtained when incorporating topographic data and provides insight into the vertical properties of the aerosol plumes. 相似文献
494.
Valeria A. Guinder Cecilia A. Popovich Juan Carlos Molinero Gerardo M. E. Perillo 《Marine Biology》2010,157(12):2703-2716
The phytoplankton of the Bahía Blanca Estuary, Argentina, has been surveyed since 1978. Chlorophyll a, phytoplankton abundance, species composition and physico-chemical variables have been fortnightly recorded. From 1978 to
2002, a single winter–early spring diatom bloom has dominated the main pattern of phytoplankton interannual variability. Such
pattern showed noticeable changes since 2006: the absence of the typical winter bloom and changes in phenology, together with
the replacement of the dominant blooming species, i.e. Thalassiosira curviseriata, and the appearance of different blooming species, i.e. Cyclotella sp. and Thalassiosira minima. The new pattern showed relatively short-lived diatom blooms that spread throughout the year. In addition, shifts in the
phytoplankton size structure toward small-sized diatoms, including the replacement of relatively large Thalassiosira spp. by small Cyclotella species and Chaetoceros species have been noticed. The changes in the phenology and composition of the phytoplankton are mainly attributed to warmer
winters and the extremely dry weather conditions evidenced in recent years in the Bahía Blanca area. Changing climate has
modified the hydrological features in the inner part of the estuary (i.e. higher temperatures and salinities) and potentially
triggered the reorganization of the phytoplankton community. This long-term study provides evidence on species-specific and
structural changes at the bottom of the pelagic food web likely related to the recent hydroclimatic conditions in a temperature
estuary of the southwestern Atlantic. 相似文献
495.
Om Prakash Stefan J. Green Pooja Singh Puja Jasrotia Joel E. Kostka 《Frontiers of Environmental Science & Engineering》2021,15(2):23
496.
Karla Ili&cacute &Dstrok ur&dstrok i&cacute Raluca Ostafe Olivera Prodanovi&cacute Aleksandra &Dstrok ur&dstrok evi&cacute &Dstrok elma Nikolina Popovi&cacute Rainer Fischer Stefan Schillberg Radivoje Prodanovi&cacute 《Frontiers of Environmental Science & Engineering》2021,15(2):19
497.
Stefan Lüpold Tim R. Birkhead David F. Westneat 《Behavioral ecology and sociobiology》2012,66(12):1607-1617
Many reproductive traits, including ejaculate characteristics, usually show remarkable seasonal variation, but the potential for such dynamics in sperm morphology has been overlooked. Several studies have revealed high within-male repeatability in sperm morphology, but samples have typically been collected within a few hours or days, and the consistency of sperm morphology over longer periods remains unexplored. Here, we tested whether ejaculate traits, including sperm morphology, sperm number, and sperm velocity, exhibit seasonal phenotypic plasticity in a long-lived seasonal breeder, the red-winged blackbird (Agelaius phoeniceus). We found absolute and/or relative flagellum length and sperm velocity to increase across the season, whereas sperm numbers within ejaculates declined. Sperm morphological traits were further positively associated with harem size or the total number of offspring that fledged in each male’s territory, suggesting that sperm morphology is likely to be linked to male reproductive quality. The underlying mechanisms of these patterns of seasonal variation remain unresolved, but we discuss our results in the context of dynamics of reproductive hormones, testicular structures and function, and reproductive behavior. 相似文献
498.
Cyanides are waste products from the pyrolysis of coal and are frequent soil pollutants in cities nowadays. Prussic acid (HCN) is a fast acting, highly toxic poison, but iron-complexed cyanides in soil are far less toxic. The phytotoxicity of free CN to basket willows (Salix viminalis) was determined with the tree transpiration test. The EC10 for t=72 h is 0.76 mg KCN (0.3 mg CN) per liter, the EC50 is 4.47 mg/l. 5 mg/l KCN are ultimately lethal. Balsam poplars (Populus trichocarpa) can survive concentrations of up to 2500 mg/l ferroferricyanide (Prussian blue), although with reduced growth. Willows survived in gas work soils with up to 452 mg/kg total CN. More CN was taken up from nutrient solution than from the soil. Complexed cyanide is probably translocated into the leaves as well. Free CN was readily eliminated from Erlenmeyers with plants growing in nutrient solution. Planting appropriate vegetation might be a suitable solution for many former gas work and mining sites. 相似文献
499.
500.