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791.
Thomas T. Shen Laurence G. Ayer 《Journal of the Air & Waste Management Association (1995)》2013,63(8):851-855
The current S02 emission test methods, based on wet chemistry, are time consuming and costly. Final results depend on at least 10 separate measurements of quantities which may introduce significant errors due to human factors especially under unfavorable field environment. Performance evaluation of several promising S02 instrumental methods indicated that results were reliable and reproducible, but instrumental problems still exist. The problems were found to be calibration, mechanical and electronic components, and sample conditioning system. An alternative method proposed requires only two separate analyses: ultimate fuel analysis and stack gas analysis for C02. This method can be further simplified with reasonable accuracy by a single measurement of sulfur in the fuel if results are corrected to 12% C02. The method can be a useful addition to the current methods, especially if cost and manpower preclude actual stack tests. A test program was conducted at four industrial and utility power plants. Results are presented with discussion to show the application and validity of the simplified method. 相似文献
792.
The paper describes the results from experimental studies and theoretical predictions of the final overpressures developed on combustion of a partial volume inside a larger closed vessel. The partial volume is assumed flammable whilst the remainder of the volume is initially filled with air alone. Particular attention is given to partial volumes of hydrogen–air mixtures. The accuracy of two theoretical models for predicting the final equilibrium pressure throughout the entire closed volume are also assessed. 相似文献
793.
Jacques M. Pasteels Arnaud Termonia Donald M. Windsor Ludger Witte Claudine Theuring Thomas Hartmann 《Chemoecology》2001,11(3):113-120
Summary. Field collected exocrine defensive secretions of nine neotropical Platyphora species were analyzed for the presence of plant acquired pyrrolizidine alkaloids (PAs) and pentacyclic triterpene saponins.
All species secrete saponins. In addition, five species feeding on Tournefortia (Boraginaceae), Koanophyllon (Asteraceae, tribe Eupatorieae) and Prestonia (Apocynaceae) were shown to sequester PAs of the lycopsamine type, which are characteristic for species of the three plant
families. The PA sequestering species commonly store intermedine, lycopsamine and their O3′-acetyl or propionyl esters as well as O7- and O9-hydroxyisovaleryl esters of retronecine. The latter as well as the O3′-acyl esters were not found in the beetles’ host plants, suggesting the ability of the beetles to esterify plant derived retronecine
and intermedine or its stereoisomers. Despite the conformity of the beetles’ PA patterns, considerable inconsistencies exist
regarding the PA patterns of the respective host plants. One host plant was devoid of PAs, while another contained only simple
necines. Since the previous history of the field collected beetles was unknown this discrepancy remains obscure. In contrast
to the Palearctic chrysomeline leaf beetles, e.g. some Oreina species which ingest and store PAs as their non-toxic N-oxides, Platyphora leaf beetles absorb and store PAs as the toxic free base (tertiary PA), but apparently avoid to accumulate PAs in the haemolymph.
This suggests that Chrysolina and Platyphora leaf beetles developed different lines of adaptations in their parallel evolution of PA mediated chemical defense.
Received 30 November 2000; accepted 5 February 2001 相似文献
794.
Katarzyna H. Kucharzyk Ronald L. Crawford Barbara Cosens Thomas F. Hess 《Journal of environmental management》2009,90(2):303-310
Perchlorate, an anion that originates as a contaminant in ground and surface waters, is both naturally occurring and manmade. Because of its toxicity, there has been increased interest in setting drinking water safety standards and in health effects when perchlorate is present at low (parts per billion (ppb)) levels. In January 2009, the EPA issued a heath advisory to assist state and local officials in addressing local contamination of perchlorate in drinking water. The interim health advisory level of 15 micrograms per liter (μg/L), or ppb, is based on the reference dose recommended by the National Research Council (NRC) of the National Academy of Sciences (NAS). This paper describes scope and extent of contaminant issues and a legal process of setting standards for perchlorate concentration in drinking water in the United States of America. 相似文献
795.
796.
Issues in developing a capacity for integrated analysis of mitigation and adaptation 总被引:2,自引:0,他引:2
As policymakers and stakeholders increasingly consider relative merits and complementarities of climate change mitigation and adaptation strategies, it is important to improve analytical capacities to support this process. Because a single analytical approach is unlikely to fit all needs, this paper explores potentials for an integrated analytical framework that incorporates both top–down and bottom–up approaches. 相似文献
797.
798.
David J. Grand Thomas K. Egglin William W. Mayo-Smith John J. Cronan Julie Gilchrist 《Journal of Safety Research》2012,43(5-6):413-415
Foreign object ingestion is a common reason for visiting an emergency department; however, wire grill-cleaning brush bristles are an uncommon foreign object. This report describes a series of twelve cases identified in a single hospital system from July 2009 through June 2012. Patients included six males and six females; ages ranged from 11 to 75 (mean: 47 years). The patients all reported recent outdoor residential food grilling and use of commercially available wire grill-cleaning brushes. The severity of injury ranged from puncture of the soft tissues of the neck, causing severe pain on swallowing, to perforation of the gastrointestinal tract requiring emergent surgery. Before cooking, persons should examine the grill surface carefully for the presence of wire bristles that might have dislodged from the grill brush and could embed in cooked food. Alternative residential grill-cleaning methods or products might be considered. 相似文献
799.
800.