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531.
532.
In this investigation, all the techniques used in the chemical recycling of polyethylene terephthalate (PET) are critically reviewed according to the overall benefits together with the environmental surcharge that they cause. Those, which are consistent with the principles of sustainable development, are indicated. Experimental data are presented for the acid hydrolysis of PET and compared with previous results on the alkaline hydrolysis of PET with, or without, the use of a phase transfer catalyst. Overall material balances are carried out for the hydrolysis of PET. Finally, it can be postulated that recycling according to the scheme: is the only one within the framework of sustainable development. Therefore, the recycling of PET does not only serve as a partial solution to the solid waste problem but also contributes to the conservation of raw petrochemical products and energy. 相似文献
533.
Felipe Hernndez‐Luis Mercedes Lemus Domingo Grandoso Mario V. Vzquez Carmen D. Arbelo 《补救:环境净化治理成本、技术与工艺杂志》2004,14(3):105-112
This article presents the results of an experimental study conducted to evaluate the behavior of two types of andisol soils found in Tenerife, Canary Islands, Spain. The soils were evaluated in relation to their buffering capacity when confronted with acid and alkaline fronts generated during electroremediation treatment. The study was conducted using a cell, which established a continuous flow of distilled water through electrode chambers to remove H+ and OH? generated during electrolysis. The results indicate that the soils had sufficient buffer capacity to support variations in pH independent of the maintenance of flow of solution in the electrode chambers. Although the mechanism of migration was not affected, the flow of water favored the movement of ions by diffusion monitoring of the electrolytic current allowed for a real‐time parameter to act as an indicator of the quantity of ions available in regions near the electrodes. © 2004 Wiley Periodicals, Inc. 相似文献
534.
Kimberly D. Elsbach 《组织行为杂志》2004,25(1):99-128
Using qualitative methods, I examine how employees in corporate office environments interpreted a variety of relatively permanent office décor (e.g., furniture, photos, personal mementos) as indicators of their colleagues' workplace identities (i.e., central and enduring categorizations regarding employees' status and distinctiveness in the workplace). Similar to the encoding of behavioral cues of identity, findings suggest that interpretation of physical identity markers begins with either (1) a top‐down process of social categorization, in which specific rules are applied to encoding a few, focal, and visually salient pieces of office decor as evidence of management prototypes, or (2) a bottom‐up process of social categorization, in which a variety of physical artifacts are examined and compared to specific managerial exemplars to develop a complex representation of workplace identity. Findings also suggest that some of the unique attributes of physical identity markers (i.e., their potential to be viewed independently from their displayer, and their relative permanence) may be associated with the focus of each profiling process (i.e., on interpreting status vs. distinctiveness, and consistency vs. change). Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
535.
The influences of organizational citizenship behavior (OCB) and workplace deviant behavior (WDB) on business unit performance were investigated using data from branches of a fast food organization. Data included measures of WDB and OCB obtained from staff, ratings of performance provided by supervisors, and objective measures of performance. It was found that WDB was negatively and significantly associated with business unit performance measured both subjectively and objectively. OCB, however, failed to contribute to the prediction of business unit performance beyond the level that was achieved by WDB. It appeared, therefore, that the presence of deviant employees among business units impinges upon the performance of the business unit as a whole, whereas OCBs had comparatively little effect. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
536.
The present study examines the interaction effect of gender of both subordinates and supervisors on subordinates' perception of differentiation of boss–subordinate relationship in an African setting. Data was collected from a total of 60 boss–subordinate dyads in four‐sex combinations obtained through a survey of a large five‐star hotel in Abuja, Nigeria. Results revealed that subordinates in opposite‐sex dyads perceived better quality of exchange than those in same‐sex dyads. The strongest quality of exchange was perceived in male boss–female subordinate dyad, while the weakest was perceived in female boss–female subordinate dyad. This emphasizes the importance of gender in the differentiation of boss–subordinate relationships in an African setting. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
537.
The air quality management (AQM) framework in the UK is a risk management approach using effects-based objectives for air pollutants to determine the need for action. The Environment Act 1995 required a National Air Quality Strategy to be published, setting out health-based standards and objectives for eight pollutants, of which seven are to managed at a local scale. Because of the variety of sources of air pollution, if the AQM process is to succeed in the long term, solutions to identified problems will be required from transport, land use and economic planning sectors of local government in liaison with various other agencies, regulators and outside bodies. As such the task is inherently multi-disciplinary and an integrated, collaborative approach will be necessary. Although this observation is now fairly well documented, there is still little guidance relating to how, in relation to air quality management, integration can actually be accomplished. This paper presents some observations from case studies undertaken as part of a longer-term research study and in particular focuses on the identified problems of involving non-air-quality professionals in a highly technical scientific process. Various approaches to the collaborative aspects of air quality management will be presented. These case studies represent local authorities of different sizes in different political and organisational situations facing a range of air quality challenges. The creation of project teams or task forces is judged particularly useful for local air quality management. Methods that could be applied more widely include appointing individuals as integrators, and rotation of key personnel. 相似文献
538.
539.
Michelle L. Soupir Saied Mostaghimi Amanda Masters Katherine A. Flahive David H. Vaughan Aida Mendez Phillip W. McClellan 《Journal of the American Water Resources Association》2004,40(1):53-66
ABSTRACT: Erosion from construction sites significantly affects water quality in receiving streams. A rainfall simulator was used to evaluate the effectiveness of different methods for controlling erosion from construction sites. Erosion control methods investigated included dry and liquid applications of polyacrylamide (PAM), hydroseed, and straw mulch. Fertilizer was also applied to each plot to examine the effectiveness of the methods in reducing nutrient losses in runoff. Runoff samples were analyzed for total suspended solids (TSS), nitrate, total Kjeldahl nitrogen (TKN), ammonium, total phosphorus (TP), and orthophosphate. Among all treatments investigated, straw mulch was the most effective treatment for controlling TSS and nutrient losses during short term and long term simulations. The low liquid PAM (half the recommended PAM) treatment resulted in the highest reduction in runoff, TSS bound nitrogen, and total nitrogen (TN) concentrations and loadings. The study results indicate that a high application rate (twice the recommended rate) of PAM could actually increase runoff and TSS losses. At a low application rate, both liquid and dry PAM were effective in reducing TSS and nutrient losses in runoff. However, application of the liquid form of PAM to construction sites is more practical and perhaps more economical than applying the PAM in the dry form. 相似文献
540.
Brent J. Dalzell Prasanna H. Gowda David J. Mulla 《Journal of the American Water Resources Association》2004,40(2):533-543
ABSTRACT: This paper studies the effectiveness of alternative farm management strategies at improving water quality to meet Total Maximum Daily Loads (TMDLs) in agricultural watersheds. A spatial process model was calibrated using monthly flow, sediment, and phosphorus (P) losses (1994 to 1996) from Sand Creek watershed in south‐central Minnesota. Statistical evaluation of predicted and observed data gave r2 coefficients of 0.75, 0.69, and 0.49 for flow (average 4.1 m3/s), sediment load (average 0.44 ton/ha), and phosphorus load (average 0.97 kg/ha), respectively. The calibrated model was used to evaluate the effects of conservation tillage, conversion of crop land to pasture, and changes in phosphorus fertilizer application rate on pollutant loads. TMDLs were developed for sediment and P losses based on existing water quality standards and guidelines. Observed annual sediment and P losses exceeded these TMDLs by 59 percent and 83 percent, respectively. A combination of increased conservation tillage, reduced application rates of phosphorus fertilizer, and conversion of crop land to pasture could reduce sediment and phosphorus loads by 23 percent and 20 percent of existing loads, respectively. These reductions are much less than needed to meet TMDLs, suggesting that control of sediment using buffer strips and control of point sources of phosphorus are needed for the remaining reductions. 相似文献