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排序方式: 共有1035条查询结果,搜索用时 31 毫秒
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Fernandez A Wendt JO Cenni R Young RS Witten ML 《The Science of the total environment》2002,287(3):265-274
Airborne particulate matter (PM) is an important environmental issue because of its association with acute respiratory distress in humans, although the specific particle characteristics that cause lung damage have yet to be identified. Particle size, acid aerosols, water-soluble transition metals (e.g. Cu, Fe, V, Ni and Zn), polyaromatic hydrocarbons, and particle composition are the focus of several popular hypotheses addressing respiratory distress. All of the above mentioned characteristics are contained in PM generated from the combustion of both pulverized coal, and biomass, including dried municipal sewage sludge (MSS). In this investigation, we report results from collaborative interdisciplinary research on the inhalation health risks caused by particles emitted from the co-combustion of municipal sewage sludge (MSS) and coal. A solid particle resuspension system was implemented to resuspend ash particles. Mice were exposed to resuspended coal and MSS/coal ash particles. Mice exposed to MSS/coal ash particulate demonstrated significant increases in lung permeability, a marker of the early stages of pathological lung injury, while the mice exposed to coal-only ash did not. These results show that the composition of particles actually inhaled is important in determining lung damage. Zinc was significantly more concentrated in the MSS/coal ash than coal ash particles and the pH of these particles did not differ significantly. Specifically, an MSS/coal mixture, when burned, emits particles that may cause significantly more lung damage than coal alone, and that consequently, the use of MSS as a 'green', CO2-neutral replacement fuel should be carefully considered. 相似文献
54.
Adsorption tests were performed on two different exhausted oils to reduce their polluting and health hazard potential: a "water-insoluble oil", utilised for automotive engine lubrication, and an "emulsified" oil, used as coolant for metal-cutting tools. Dolomite, a low-cost recovery material, was used to prepare two effective adsorbents: (a) a mixed Ca and Mg oxide obtained by thermal decomposition of dolomite at 1800 degrees C, and (b) an activated material obtained by submitting this product to chemical treatment with HCl. Preliminary tests carried out with an excess of the former material showed that the insoluble oil was adsorbed with lower yield (Y = 0.40) than the soluble (emulsified) oil (Y = 0.60). The material activation with HCl remarkably improved the adsorption of soluble oil organic fraction (Y > 0.90), while only a little increase in the removal yield was observed for the insoluble oil (Y = 0.44). The results presented and discussed in this work pointed out that the products of dolomite calcination can successfully replace the conventional adsorbing materials in the removal of organic pollutants, with particular concern to exhausted soluble oils, which cannot usually be recycled, thus reducing the operational costs of their treatment. 相似文献
55.
Giovanni Pioggia Roberta Igliozzi Marcello Ferro Arti Ahluwalia Filippo Muratori Danilo De Rossi 《IEEE transactions on neural systems and rehabilitation engineering》2005,13(4):507-515
It is well documented that the processing of social and emotional information is impaired in people with autism. Recent studies have shown that individuals, particularly those with high functioning autism, can learn to cope with common social situations if they are made to enact possible scenarios they may encounter in real life during therapy. The main aim of this work is to describe an interactive life-like facial display (FACE) and a supporting therapeutic protocol that will enable us to verify if the system can help children with autism to learn, identify, interpret, and use emotional information and extend these skills in a socially appropriate, flexible, and adaptive context. The therapeutic setup consists of a specially equipped room in which the subject, under the supervision of a therapist, can interact with FACE. The android display and associated control system has automatic facial tracking, expression recognition, and eye tracking. The treatment scheme is based on a series of therapist-guided sessions in which a patient communicates with FACE through an interactive console. Preliminary data regarding the exposure to FACE of two children are reported. 相似文献
56.
Substrate age and precipitation effects on Hawaiian forest canopies from spaceborne imaging spectroscopy 总被引:1,自引:0,他引:1
Gregory P. Asner Kimberly M. Carlson Roberta E. Martin 《Remote sensing of environment》2005,98(4):457-467
We used spaceborne imaging spectroscopy provided by the Earth Observing-1 Hyperion sensor to quantify the relative importance of precipitation and substrate age that control ecosystem development and functioning in Metrosideros polymorpha rainforests of Hawaii. Four hyperspectral vegetation indices provided metrics of forest canopy structure, biochemistry and physiology to compare along gradients of annual rainfall (750 to > 6000 mm year− 1) and substrate age (0 to 250,000 years). The canopy greenness index NDVI increased with annual precipitation and substrate age, but saturated in forests with rainfall of 3000 mm year− 1. Precipitation and substrate age were roughly equal contributors to the observed greenness of the forests. A canopy water content index (NDWI) also increased with precipitation and substrate age, but did not reach a maximum until very wet (> 5000 mm year− 1) forest conditions were encountered on the oldest substrates. The water index appears superior to the NDVI in capturing spatial and climate-substrate driven variations in canopy structure. The photochemical reflectance index (PRI) indicated highest light-use efficiency levels in canopies on the most developed substrates and at annual precipitation levels of 3-4500 mm year− 1. A leaf carotenoid index (CRI) suggested a maximum canopy photosynthetic capacity at ∼ 4000 mm rainfall year− 1 on the oldest substrates. These results quantify the sensitivity of rainforest canopies to changing precipitation and soil conditions, and they corroborate plot-scale analyses in native Hawaiian forests ecosystems. Structural and functional studies of remote rainforest regions are possible with spaceborne imaging spectroscopy, and could be used to understand the dynamics of rainforests with climate change. 相似文献
57.
The role of pore structure in the catalytic behavior of “unaged” and “aged” silica-alumina catalysts
This is a review of research concerning the role played by the porous structure of silica-alumina catalysts on the evolution of organic catalytic processes. A strong effect of the geometrical shape of the pores on catalytic activity and selectivity has been evidenced. The experimental results have also been interpreted by means of a simplified mathematical model, able to relate selectivity for a reaction of the type A → B → C to the geometrical features of macro-microporous catalyst pellets, or granules. The theoretical results are in qualitatively satisfactory agreement with the experimental data. 相似文献
58.
Hee-Jang?MoonEmail author Roland?Borghi 《Journal of Mechanical Science and Technology》2004,18(8):1470-1478
In this paper, a new “presumed” Probability Density Function (PDF) approach coupled with a Lagrangian tracking method is proposed for turbulent combustion modeling. The test and the investigation of the model are conducted by comparing the model results with DNS data for a premixed flame subjected in a decaying turbulent field. The newly constructed PDF, which incorporates the instantaneous chemical reaction term, demonstrates consistent improvement over conventional assumed PDF models. It has been found that the time evolution of the mean scalar, the variance and the mean reaction rate are strongly influenced by a parameter deduced by a Lagrangian equation which takes into account explicitly the local reaction rate. Tests have been performed for a moderate Damköhler number, and it is expected the model may cover a broader range of Damköhler number. The comparison with the DNS data demonstrates that the proposed model may be promising and affordable for implementation in a moment-equation solver. 相似文献
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Pichini S Pacifici R Pellegrini M Marchei E Lozano J Murillo J Vall O García-Algar O 《Analytical chemistry》2004,76(7):2124-2132
A procedure based on liquid chromatography-mass spectrometry (LC-MS) is described for determination of amphetamine, methamphetamine, and methylendioxy derivatives in meconium, using 3,4-methylendioxypropylamphetamine as internal standard. The analytes were initially extracted from the matrix by 17 mM methanolic HCl. Subsequently, a solid-phase extraction with Bondelut Certify columns was applied. Chromatography was performed on a C(18) reversed-phase column using a linear gradient of 10 mM ammonium bicarbonate, pH 9.0-methanol as a mobile phase. Analytes were determined in LC-MS single ion monitoring mode with an atmospheric pressure ionization-electrospray interface. The method was validated in the range 0.005-1.00 microg/g using 1 g of meconium per assay. Mean recoveries ranged between 61.1 and 87.2% for different analytes. The quantification limits were 0.005 microg/g meconium for amphetamine, methamphetamine, and 4-hydroxy-3-methoxymethamphetamine and 0.004 microg/g meconium for 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyethylamphetamine, and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine. The method was applied to analysis of meconium in newborns to assess eventual fetal exposure to amphetamine derivatives. 相似文献