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251.
Organizational identification is defined as a perceived oneness with an organization and the experience of the organization's successes and failures as one's own. While identification is considered important to the organization, it has not been clearly operationalized. The current study tests a proposed model of organizational identification. Self-report data from 297 alumni of an all-male religious college indicate that identification with the alma mater was associated with: (1) the hypothesized organizational antecedents of organizational distinctiveness, organizational prestige, and (absence of) intraorganizational competition, but not with interorganizational competition, (2) the hypothesized individual antecedents of satisfaction with the organization, tenure as students, and sentimentality, but not with recency of attendance, number of schools attended, or the existence of a mentor, and (3) the hypothesized outcomes of making financial contributions, willingness to advise one's offspring and others to attend the college, and participating in various school functions. The findings provide direction for academic administrators seeking to increase alumni support, as well as for corporate managers concerned about the loyalty of workers in an era of mergers and takeovers.  相似文献   
252.
Modelling urban air pollution   总被引:1,自引:0,他引:1  
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253.
Ozone generation is computed in a one-dimensional photochemistry code following convective redistribution of tropical urban effluent into the free troposphere. Simulations are run at several stages of pollutant dilution by surrounding surface air. A threshold boundary layer NOx concentration of 300 pptv is established for significant production enhancements at upper levels. Areas defined by the 300 pptv level are examined in the Gaussian dispersion framework based on a wet season plume event observed in Amazonia. Pollution travels slowly in the sluggish winds of the equatorial trough. Daily storms are likely to interrupt the effluent while coverages are still on the order of few thousand square kilometers and NOx concentrations are above the threshold. Dry season plume sizes are difficult to assess because local concentration data are scarce, but it is conceivable that the faster trade winds lead to a several fold extension.  相似文献   
254.
The Coordinating Research Council held its 14th Vehicle Emissions Workshop in March 2004, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research.  相似文献   
255.
Structure of native vertebrate faunas within 12 different forest types were related to features of the natural fire regime. Relations between faunal structure and fire regime followed patterns expected if faunas were adapted to fire regimes. Proportions of species breeding early in succession tended to increase with increasing fire size or burn rate (ha/year; p = 0.03); those breeding late in succession tended to decrease ( p = 0.04). As fire size increased, proportions of species breeding in cavities decreased ( p < 0.01). Proportions of species using downed wood to breed increased as the interval between fires increased and downed wood accumulated ( p < 0.01). Forestry practices to maintain biodiversity should mimic natural disturbance patterns, which differ across forest types. Implications for management to maintain vertebrate diversity are summarized in terms of the silvicultural system employed, the size of patches logged, the rate of timber removal, and the appropriate degree of connectivity among unlogged patches.  相似文献   
256.
To determine if an aquifer contaminated with volatile organic compounds (VOCs) has potential for natural remediation, all natural processes affecting the fate and transport of VOCs in the subsurface must be identified and quantified. This research addresses the quantification of air-phase volatile organic compounds (VOCs) leaving the unsaturated zone soil gas and entering the atmosphere-including the additional flux provided by advective soil-gas movement induced by barometric pumping. A simple and easy-to-use device for measuring VOC flux under natural conditions is presented. The vertical flux chamber (VFC) was designed using numerical simulations and evaluated in the laboratory. Mass-balance numerical simulations based on continuously stirred tank reactor equations (CSTR) provided information on flux measurement performance of several sampling configurations with the final chamber configuration measuring greater than 96% of model-simulated fluxes. A laboratory device was constructed to evaluate the flux chamber under both diffusion-only and advection-plus-diffusion transport conditions. The flux chamber measured an average of 82% of 15 diffusion-only fluxes and an average of 95% of 15 additional advection-plus-diffusion flux experiments. The vertical flux chamber has the capability of providing reliable measurement of VOC flux from the unsaturated zone under both diffusion and advection transport conditions.  相似文献   
257.
The Coordinating Research Council held its thirteenth Vehicle Emissions Workshop in April 2003, when results of the most recent on-road vehicle emissions research were presented. Ongoing work from researchers who are engaged in improving understanding of the contribution of mobile sources to ambient air quality and emission inventories is summarized here. Participants in the workshop discussed efforts to improve mobile source emission models, the role of on-board diagnostic systems in inspection and maintenance programs, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research.  相似文献   
258.
Current surface mine regulations as ascribed under the Surface Mining Control and Reclamation Act of 1977 require that mine lands be returned to the approximate original contours (AOC) with an area coverage of at least 70% and to biological productivity equal to or greater than that which existed prior to mining. Six different procedures were evaluated on nine mine sites in northwestern Pennsylvania as to their suitability to estimate aboveground biomass on mines reclaimed as hayland and pastures. Biomass estimates determined by different procedures were compared to those obtained by random clip plots and with landowner estimates of the annual yield from each site. Biomass estimates determined from a disk meter and landowner interviews varied approximately ±10% from those obtained from random clip plots compared to a variation of ±8%–37% for the other procedures. The number of samples required to obtain reliable estimates within ±10% of the mean at 95% confidence intervals varied among the different sampling procedures according to the variance in biomass on the site. Although all procedures may be used either singly or in combination to estimate above ground biomass on reclaimed mine lands, the combination of the disk meter, profile board, and vegetation height is recommended because of their ease of measurement compared to the other procedures.  相似文献   
259.
The implementation of the European Water Framework Directive requires reliable tools to predict the water quality situations in streams caused by planned land use changes at the scale of large regional river basins. This paper presents the results of modelling the in-stream nitrogen load and concentration within the macro-scale basin of the Saale river (24,167 km2) using a semi-distributed process-based ecohydrological dynamic model SWIM (Soil and Water Integrated Model). The simulated load and concentration at the last gauge of the basin show that SWIM is capable to provide a satisfactory result for a large basin. The uncertainty analysis indicates the importance of realistic input data for agricultural management, and that the calibration of parameters can compensate the uncertainty in the input data to a certain extent. A hypothesis about the distributed nutrient retention parameters for macro-scale basins was tested aimed in improvement of the simulation results at the intermediate gauges and the outlet. To verify the hypothesis, the retention parameters were firstly proved to have a reasonable representation of the denitrification conditions in six meso-scale catchments. The area of the Saale region was classified depending on denitrification conditions in soil and groundwater into three classes (poor, neutral and good), and the distributed parameters were applied. However, the hypothesis about the usefulness of distributed retention parameters for macro-scale basins was not confirmed. Since the agricultural management is different in the sub-regions of the Saale basin, land use change scenarios were evaluated for two meso-scale subbasins of the Saale. The scenario results show that the optimal agricultural land use and management are essential for the reduction in nutrient load and improvement of water quality to meet the objectives of the European Water Framework Directive and in view of the regional development plans for future.  相似文献   
260.
ABSTRACT

This study investigated the effect of adding vanadium (V) to natural manganese oxide (NMO) in ammonia (NH3) selective catalytic reduction (SCR). The addition of V to NMO decreased the catalytic activity at low temperatures by blocking the active site. However, the enhancement of catalytic activity was achieved by controlling NH3 oxidation at high temperatures. From the NH3 temperature programmed desorption and oxygen on/off test, it was confirmed that the amount of Lewis acid site and active lattice oxygen of the catalyst affects the catalytic performance at low temperature

IMPLICATIONS Recently, NMO and manganese oxide have been reported as SCR catalysts. They usually have only reported the reaction characteristics and catalytic activity on the NH3 SCR over NMO or manganese/metal oxide catalysts. There are no studies about the effect of addition of V to NMO. Therefore, this study investigates the catalytic activity and reaction characteristics on the NH3 SCR over NMO and V/NMO, and a new application is proposed based on the conclusions of this study.  相似文献   
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