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Every year about 40 000 m3 of waste solutions from photographic fixing and developing processes are produced in Germany. A new method of reclaiming some base chemicals (silver, fixing salt, gypsum and ammonia) from these solutions has been developed for black and white photographic processes. The remaining waste water has a low COD-value and low concentration of dissolved salts. This method is considered further to develop the state-of-the-art technique and is economically feasible. 相似文献
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All businesses are continually seeking ways to increase productivity, improve customer satisfaction, reduce waste, and minimize costs. However, small businesses are frequently overlooked in discussions of the implementation of environmental quality improvements in conjunction with management practice improvements. Humes Collision Center incorporated new waste reduction techniques when it expanded its old facilities in 1992, and it was able to achieve the benefits of cost and waste reduction. Humes Collision Center repairs an average of 500 cars annually and is a very small quantity generator of hazardous waste, as defined by the Minnesota Pollution Control Agency. This case study documents the waste minimization and economic benefits at the new autobody repair facility in Hermantown, Minnesota. 相似文献
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Extra-pair paternity in willow ptarmigan broods: measuring costs of polygyny to males 总被引:3,自引:0,他引:3
J. R. Freeland S. J. Hannon G. Dobush P. T. Boag 《Behavioral ecology and sociobiology》1995,36(5):349-355
Willow ptarmigan are one of only three monogamous grouse species in North America. However, in some populations between 5 and 20% of individuals pair polygynously. It has been suggested that monogamy may be maintained by the high cost of polygyny to males. We have used DNA fingerprinting to assess the actual reproductive success of both monogamous and polygynous adults. We determined whether or not the putative parents were the biological parents of the chicks from 38 broods. Of these clutches 30 were from monogamous matings, and 8 were from bigamous matings. Of the 207 chicks from monogamous matings 96% were within-pair offspring, compared to 67% of the 49 chicks from bigamous matings. All extra-pair offspring chicks resulted from extra-pair fertilizations (EPFs), and there were no instances of intraspecific nest parasitism. Mate guarding by monogamous males seems to be a highly effective method for maintaining genetic monogamy, as the only cases in which EPFs occurred were when the resident female left the territory for a few days or when a second female visited the territory. Our results support the notion that certainty of parentage may be one factor constraining willow ptarmigan males to be monogamous. 相似文献