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[en] Forests on the Kola Peninsula in Northern Russia grow close to the northern tree line. They are subjected to both natural and anthropogenic stress factors. The Cu-Ni smelter 'Severonikel' (Lat. 67 deg 55'N; Long. 32 deg 57'E) near Monchegorsk is one of the two major sources of sulphur dioxide and heavy metals emissions on the Kola Peninsula. These emissions have caused significant deterioration of the surrounding vegetation. The thesis demonstrates how methods of Remote sensing, ground survey and mathematical modelling can be integrated for monitoring of the smelter's environmental impact on the surrounding vegetation: ground truth data are used for calibration of remote-sensed data, which further serve to verify mathematical models. The study aims were: * to estimate the scale of airborne sulphur pollution from the smelting industry on the Kola Peninsula and its effect on vegetation; * to assess spatial extent of the forest decline in the 'Severonikel' smelter impact zone; * to display dynamics of the forest damage area in spatial and temporal perspective; * to validate the Gaussian plume sector model and the IIASA forest impact model as components of the analysis of forest damage. The Regional Acidification Information and Simulation model (RAINS) was applied to calculate sulphur deposition and loads in Fennoscandia in order to assess the contribution of the Kola sources to the deposition pattern in the region. The percentage of the ecosystems where the critical load had been exceeded was calculated. For more detailed assessments, calculations based on local and meso-scale models were made. Landsat-MSS summer images from 1978, 1986 and 1992 and a Landsat -TM image from 1996 were used for change-detection analyses. The methods applied were bandwise histogram matching and subsequent differencing. An unsupervised classification of land-cover was made using the 1996 Landsat-TM image. In situ observations of vegetation type and degradation levels on permanent field plots were used for labelling the classes. Multispectral changes observed between 1978 and 1992 were used to evaluate the relevance of the Gaussian plume model as a component for assessment of forest decline. The IIASA model for accumulated impact in forests under long-term exposure to airborne sulphur was applied for the period of 1960-1996. The input data used were plant sensitivity parameters and SO2 ambient concentrations predicted at a previous stage. The model was validated by ground truth data and the results of the 1996 classification. Effects of topography and episodes of high concentrations were additionally investigated by a 3D numerical modelling Results: * Comparative analysis by the RAINS model showed a significant, but local impact of the Kola sources on adjacent parts of the Nordic countries. * Remote sensing has revealed vegetation decline in large areas around the 'Severonikel'. The damaged area expands more north than south of the smelter due to a dominance of southern winds during the vegetation period, and a sheltering role of topography as revealed by 3D modelling. * Multispectral changes detected between 1978 and 1992 were found to have a statistically significant correspondence to the modelled long-term SO2 concentration levels in ambient air. This validates the Gaussian plume model. * The impact model was validated by in situ field data and by the classified 1996 scene. * Both Remote sensing analysis and the impact model show a rapid expansion of the degraded area during 1978-1992 and its stabilisation since that time which is consistent with the reduced emissions. * An exceptional expansion of forest damage south of the smelter in 1992 is likely to be linked to an episode of high concentration prior to the image acquisition or extreme climatic conditions
[en] During solubilization processes of low grade sulphidic ores, the auto trophic bacteria oxidize reduced sulphur compounds and ferrous iron to sulphates and ferric iron respectively. The ore leaching bio topes are not only colonized by auto trophic bacteria (Thiobacillus spp., Leptospirillum ferro oxidans and sulfolobus sp.) but the heterotrophic microorganisms, including bacteria and fungi of various species are also found in these habitats. The autotrophs, in addition to energy metabolism, also produce organic compounds which in excess amount inhibit their growth. Through the utilization of such compounds and also through the production of carbon dioxide and ammonia, these heterotorphs can help bio leaching processes. Effect of one of the heterotrophs; methylobacterium sp., a nitrogen scavenger, found in as association with the thio bacilli in one of the leaching bio tope in Germany was studied in leaching of a carbonate bearing complex (containing copper, iron, zinc and lead) sulphidic ore, in shake flask studies. T. ferro oxidans (Strain F-40) reported to be non nitrogen fixer and strain F-41, a nitrogen fixing thiobacillus were studied for leachability behaviour alone and in combination with T. thio oxidans (lacking nitrogen fixing ability) using media with and without added ammonium nitrogen. In addition the effect of methylobacterium sp. (alt-25) was also tested with the afore mentioned combinations. Nitrogen fixation by T. ferro oxidans did not suffice the nitrogen requirement and the leaching system in laboratory needed addition of nitrogen. The heterotrophic nitrogen scavenger also did not have a positive influence in nitrogen limited system. In case where ammonium nitrogen was also provided in the media, this heterotroph had a negative in own growth and leaving lesser amount available for thio bacilli. This high amount of acid is a limiting factor in bio leaching of high carbonate uranium ores. Uranium ore ecosystems have also been found to contain association of auto trophic and heterotropic microorganisms. Use of some heterotrophs for production of sufficient acid from molasses for pretreatment of uranium ore has also been discussed. (author)
[en] Highlights: • The Environmental Kuznets Curve (EKC) has been estimated at the national and the provincial level in China. • There exists aggregation bias in estimating the national level EKC for sulfur dioxide emission. • The local government should play more important role in environmental policy-making. - Abstract: Aggregation bias may lead to a wrongly estimated Environmental Kuznets Curve (EKC), and misguide the policy-makers. This paper aims to test the existence of aggregation bias in the Environmental Kuznets Curve with the sulfur dioxide (SO2) emission. The empirical methods robust to cross-sectional dependence and slope heterogeneity reveals that the estimation of SO2 EKC in China suffers from aggregation bias. The results with the disaggregate data cannot support the EKC estimated at the aggregate level. The finding of aggregation bias has several policy implications. First, the government should not be misled by the false relationship between the pollutant emission and the real GDP per capita at the aggregate level. Second, the local governments should play more important roles in making environmental protection policies since the more disaggregate data can mitigate the aggregation bias. To provide enough incentives to the local government, the Chinese national government should align the interests of the local governments with those of the national government. On the other hand, the findings indicate that China can stick to the policy of encouraging foreign direct investment, openness and financial development since they have not influenced the SO2 emission in China.
[en] The present development, including development of new leaching processes and equipment and soon, in bacteria leaching of uranium and gold ores at home and abroad are described. Opinions and advices are presented
[en] A new type of sample preparation device and its reactor for sulfur isotope in sulfide and sulfate experiment is developed. The trial experiment proved that the sample preparation device and its reactor are characterized with good vacuum, easy to use, clean, high efficient and low cost to produce sulfur dioxide of high purity, and the analytical results are accurate and reliable. The device and reactor can fully meet for the analysis on the sulfur isotope in various sulfide and sulfate. (authors)
[en] Sulfur dioxide (SO2) and nitrogen oxides (NOX) are major air pollutants. Before emitting flue gas into the atmosphere, these pollutants must be removed using various processes. A sol-gel process has been developed to prepare alumina granular support and catalyst. The sol-gel-derived alumina granules have a large surface area, large pore volume, uniform pore size distribution, and excellent mechanical properties such as attrition resistance and crush strength. This paper discussed an experiment that synthesized two catalysts using the sol-gel oil-drop method. The paper described the experimental procedure and presented the results of the experiment. This included the effect of temperature on the catalytic activity of CuO-CeO2-MnOx/y-Al2O3 catalysts; desorption of ammonia (NH3) and nitric oxide (NO) on the CuO-CeO2-MnOx/y-Al2O3 catalysts; transient response of NH3 and NO on CuO-CeO2-MnOx/y-Al2O3 catalysts; and the reaction kinetics and characterization of CuO-CeO2-MnOx/y-Al2O3 catalysts. It was concluded that the CuO-CeO2-MnOx/y-Al2O3 catalysts made by the sol-gel method have higher activity and a wider operating temperature range. 17 refs., 1 tab., 9 figs
[en] Hydrogen can be an attractive energy if it can be produced cleanly and in a cost effective manner. Nuclear energy can be used as a source of a high temperature process up to 1000 for a hydrogen production. The sulfur-iodine (SI) cycle is a baseline candidate thermo-chemical process. It consists of the following three chemical reactions which yield a dissociation of water. The decomposition at a high temperature of the sulfuric acid is the most energy-demanding reaction both from fundamental and applied points of views which represents the key reaction of the whole SI cycle. In this paper, a shell-and-catalyst-packed-tube type is selected and its fluidic characteristics are applied to an overall heat transfer coefficient calculation. As a result of the study, the sulfur trioxide decomposers for 300mole/s (200MWth VHTR 40% thermal efficiency) and 60mole/s (40MWth VHTR 40% thermal efficiency) hydrogen production rates are presented and discussed
[en] Following the great flooding of summer 1998, the mid-lower Yangtze Basin further suffered from another large flooding in summer 1999. Successive droughts through three recent summers (1997-1999) appeared in north China in addition, leading to an abnormal summer climate pattern of ''north drought with south flooding''. Such southward move of the summer monsoon rainy belt in east China started in the late 1970s-early 1980s. Its main cause may not be a purely natural climate change, but the acceleration of industrialization in east China could play a major role by emitting large volumes of SO2, especially from the rapidly growing rural factories of east China. The annual release of SO2 in China exceeded 20Tg during 1992-1998, so dense sulfate aerosols covered the central east China which significantly reduced the sunlight. Although present estimates for the changes of clear sky global solar radiation may include some error, they show that the negative radiative forcing of sulfate aerosols in central east China by far exceeds the effect of greenhouse warming in summer. Hence the mid-summer monsoon rainy belt of east China has a trend moving southward in 21 recent years (1979-1999), showing the very sensitive characteristic of the summer monsoon system to the change in heat equilibrium of the land surface. The occurrence rate of summer climate pattern of ''north drought with south flooding'' in east China during 21 recent years is the largest since AD 950; such anomalous climate has brought large losses to China. The only possible way to reverse this southward trend of summer monsoon rainy belt is to significantly reduce air pollution by using more clean energy. Recently, the PRC has paid serious attention to this problem by adopting a series of countermeasures. (author)
[en] The dielectric barrier corona discharge (DBCD) in a wire-cylinder configuration and the dielectric barrier discharge (DBD) in a coaxial cylinder configuration are studied. The discharge current in DBD has a higher pulse amplitude than in DBCD. The dissipated power and the gas-gap voltage are calculated by analyzing the measured Lissajous figure. With the increasing applied voltage, the energy utilization factor for SO2 removal increases in DBCD but decreases in DBD because of the difference in their electric field distribution. Experiments of SO2 removal show that in the absence of NH3 the energy utilization factor can reach 31 g/k Wh in DBCD and 39 g/kWh in DBD. (authors)
[en] Sulfur dioxide is a major air pollutant in the environment. Fortunately, the plant purification system can effectively reduce SO2 pollution. However, the effect mechanism of plant purification system for the dynamic evolution of SO2 remains incompletely clear. In this work, inspired by the “Boston ivy,” we successfully designed and constructed a semi-continuous plant system. Subsequently, based on the “vine-like plant” and the “island-like plant,” the semi-continuous plant system and the isolated plant system are selected as the models of plant purification system, respectively. The dynamic evolution of SO2 in the plant systems is investigated using the computational fluid dynamic (CFD) method. It is demonstrated that the dynamic evolution of SO2 is impacted by the plant structure and the flow path ((cg/lg) + (cl/ll)). In the semi-continuous plant system, the strong flow paths with gradually weakened fluctuation are restricted by this special plant structure, the length of flow paths are extended, and more SO2 can be dissolved. In the isolated plant system, the mild flow paths with linear relationship can easily pass through the plants, such that only a little SO2 is dissolved. Overall, the present study opens a new path into the dynamic evolution of SO2 pollution in the plant systems, which helps providing guidance for the designing of plant purification system.