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951.
Work teams are being utilized more frequently to give organizations access to the broader knowledge and skill base of employees, as well as to provide for adaptive, efficient decision‐making. In teams, we argue that constructive confrontation norms are an important contingency variable in the relationship between mental model similarity and decision quality. Mental model similarity helps team members understand one another's perspectives and reduces the likelihood of conflict. Accordingly, mental model similarity improves decision quality. When strong norms of constructive confrontation are in place, however, teams are in a better position to reap the benefits of conflict (greater diversity of inputs) without experiencing its negative consequences. Thus, when constructive confrontation norms are strong, less mental model similarity (i.e., more diversity of perspectives) is likely to improve decision quality. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
952.
953.
Peschka M Fichtner N Hierse W Kirsch P Montenegro E Seidel M Wilken RD Knepper TP 《Chemosphere》2008,72(10):1534-1540
Fluorinated surfactants have become essential in numerous technical applications due to their unparalleled effectiveness and efficiency. The environmental persistence of the non-biodegradable perfluorinated alkyl moiety has become a matter of concern. Therefore, it was searched for new molecules with chemically stable fluorinated end groups which can be microbially transformed into labile fluorinated substances. One prototype substance, 10-(trifluoromethoxy)decane-1-sulfonate, has shown biomineralization. Monitoring the formation of metabolites over time elucidated the mechanism of biotransformation. Analysis was performed utilizing liquid chromatography-single quadrupole mass spectrometry (LC-MS) and quadrupole-time of flight tandem mass spectrometry (QqTOF-MS). It was possible to distinguish between two major degradation pathways of the fluorinated alkylsulfonate derivative: (i) a desulfonation and subsequent oxidation and degradation of the alkyl chain being predominant and (ii) an insertion of oxygen with a subsequent cleavage and degradation of the molecule. The utilized trifluoromethoxy-endgroup resulted in instable trifluoromethanol after degradation of the alkyl chain, which led to a high degree of mineralization of the molecule. 相似文献
954.
Effects of pig manure compost and nonionic-surfactant Tween 80 on phenanthrene and pyrene removal from soil vegetated with Agropyron elongatum 总被引:2,自引:0,他引:2
This paper evaluates the effects of pig manure compost (PMC) and Tween 80 on the removal of phenanthrene (PHE) and pyrene (PYR) from soil cultivated with Agropyron elongatum. Soils spiked with about 300mgkg(-1) of PHE and PYR were individually amended with 0%, 2.5%, 5% and 7.5% (dry wt) of PMC or 0, 20 and 100mgkg(-1) of Tween 80. Unplanted and sterile microcosms were prepared as the controls. PAH concentration, total organic matter (TOM), dissolved organic carbon (DOC), total heterotrophic and PAH degrading microbial populations in soil were quantified before and after 60d period. The results indicated that A. elongatum could significantly enhance PYR removal (from 46% to 61%) but had less impact on PHE removal (from 96% to 97%). Plant uptake of the PAHs was insignificant. Biodegradation was the key mechanism of PAH removals (<3% losses in the sterile control). Increase in PMC or Tween 80 levels increased the removal of PYR but not of PHE. Maximal PYR removal of 79% and 92% were observed in vegetated soil receiving 100mgkg(-1) Tween 80 and 7.5% PMC, respectively. Enhanced PYR removal in soil receiving PMC could be explained by the elevated levels of DOC, TOM and microbial populations as suggested by Pearson correlation test. While the positive effect of Tween 80 on PYR removal could probably due to its capacities to enhance PYR bioavailability in soil. This paper suggests that the addition of either PMC or nonionic-surfactant Tween 80 could facilitate phytoremediation of PAH contaminated soil. 相似文献
955.
Heeb NV Schweizer WB Mattrel P Haag R Gerecke AC Schmid P Zennegg M Vonmont H 《Chemosphere》2008,73(8):1201-1210
Hexabromocyclododecanes (HBCDs) are high production volume chemicals (>20000 ty(-1)) used as flame retardants for plastics and textiles. Lately, we reported on the stereoselective isomerization of beta-HBCDs. Herein we present insights into the mechanism and kinetics of (+)gamma- to (+)alpha- and of (-)gamma- to (-)alpha-HBCD isomerization. Only two of the six bromine atoms migrated, indicating that rearrangements of gamma- to alpha-HBCDs are regio- and stereoselective as well. The apparent first-order isomerization rate constants increased from 0.0013 to 0.0031 to 0.0070 min(-1) at 120, 130, and 140 degrees C, respectively, corresponding to half-lives of 540, 230, and 99 min. Thus, a thermal treatment of materials containing gamma-HBCDs at temperatures >100 degrees C may induce the formation of alpha-HBCDs and, hence, may alter the diastereomeric ratio of a HBCD mixture. The inversion of vicinal dibromides in like-configurations (RR/SS) prevailed, whereas unlike-configurations (RS/SR) were not affected. An intramolecular, stereoselective migration of neighboring bromine atoms via a four-center transition state would explain the observed stereoisomer pattern and first-order kinetics. Despite the fact that vicinal dibromides in HBCDs prefer synclinal (gauche) conformations, antiperiplanar (staggered) conformations are assumed to facilitate concerted 1.2-shifts of both bromine atoms. A conformation analysis revealed that under kinetic control, only those bromine atoms in the more flexible part of the molecules are migrating, whereas those in the conserved triple-turn motive were not affected. Thus, this structural motive, common to all alpha-, beta-, and gamma-HBCDs, is more rigid and less reactive than the flexible part, containing the reacting dibromides in like-configurations. 相似文献
956.
Humic acids, extracted from sludge at the biologic-mechanical sewage treatment plant in Jastrzebie Zdroj, have been investigated by means of (1)H, (13)C and (31)P NMR spectroscopy. Sludge samples for studies were taken from the primary settling tank, the nitrification chamber, the digestion chamber and the sludge drying beds. The (1)H NMR analysis of humic acid extracted from sludge at various stages of sewage treatment confirmed the presence of the functional groups that are characteristic for humic substances, and the analysis showed changes in their relative intensities. The (13)C NMR indicated that the aromatisation of the humic acid increased during sewage treatment. Moreover, the analysis of the (31)P NMR spectra allowed us to observe the changes in the phosphorus groups of the studied humic acids. 相似文献
957.
We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g mL−1 for TCE and 0.25 g mL−1 for benzene and toluene. The solubility limit increased from 21 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20 mM. For TCE, the solubility increased from 8 mM to more than 1000 mM. Solubility for TCE (trichloroethylene) was most heavily impacted by biomass levels, changing by two orders of magnitude as the microbial concentrations approach those in biofilms. 相似文献
958.
959.
Aishah S. A. K. Sharifah Hanafiah Zainal Abidin Mohamad R. Sulaiman Kheng H. Khoo Hairi Ali 《Journal of Material Cycles and Waste Management》2008,10(2):116-123
Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems
of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely
affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one
possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration
of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal
solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment
may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate
the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW
collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and
chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in
the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable
for treating MSW. 相似文献
960.
Markéta Julinová Marie Dvořáčková Jan Kupec Jitka Hubáčková Martina Kopčilová Jaromír Hoffmann Pavol Alexy Anna Nahálková Ida Vašková 《Journal of Polymers and the Environment》2008,16(4):241-249
Improving biodegradability of PVA/starch blends is a reality already documented by a number of works. Admittedly, mechanical
properties of products (for example, tensile strength) are somewhat worse, but suitable composition optimizing or chemical
modifying of starch may eliminate the problem to a large degree. This work is an attempt to find another potential effect
influencing biodegradability, that of technological procedure for producing films from these blends on an extruder. The procedure
with a so-called pre-extrusion step (two-stage) and dry-blend (single-stage) produced blends of slightest differences in achieved
biodegradability (virtually within limits of experimental error) in aerobic (76 vs. 79%) as well as anaerobic breakdown (48
vs. 52%). Conversely, morphological analysis exhibited superior homogeneity of films prepared by the two-stage process; their
tensile strength was also higher. 相似文献