Marketing issues related to waste-grown aquatic foods

Environmental Management - Are societal wastes all bad? Some of them, including heat from power plants and certain organic wastes, have been demonstrated to be potentially valuable for growing...     

The functional significance of infanticide in a population of California ground squirrels (Spermophilus beecheyi)

Naturally-occurring infanticide was observed in a population of California ground squirrels (Spermophilus beecheyi). In four seasons, 40 infanticides were observed. All victims were post-emergent pups. Of 37 killings in which the killer was sexed 36 were by females. All infanticidal females were mothers at the time they killed, but in no case was a mother seen to kill or harm her own young. The victim was cannibalized in 22 cases and taken immediately into the killer’s burrow in 16 others. In no case did killers gain access to the victimized mother’s burrow or territory and female pups were not killed preferentially over males. In light of evolutionary explanations, infanticide in this population may best fit the resource exploitation hypothesis, in which killers commit infanticide to gain a nutritional benefit. Resource competition is a possible auxiliary explanation, since any time a female kills unrelated young she is eliminating possible competitors to her own offspring. This behavior could confer a fitness advantage on killers or it could be an adaptively neutral, alternative feeding strategy. More data are necessary to distinguish between these hypotheses. Received: 26 January 1995/Accepted after revision: 9 September 1995     

The measurement of resource rents: An application to Canadian nickel

Once the ‘risk’ of the industry is recognized, there are at least two sources of higher-than-normal returns to investment in mineral extraction: Ricardian rents to resources with different economic qualities and monopoly rents. An estimate of the relative importance of these sources in the Canadian nickel industry over the period 1961-74 is made and it is found that Ricardian rents and, for one firm, monopoly rents, were important.     

Decision making for multiple utilization of water resources in New Zealand

The Clutha is the largest river in New Zealand. The last two decades have witnessed major conflicts centered on the utilization of the water resources of the upper Clutha river. These conflicts have by no means been finally resolved. The focus of this article is on institutional arrangements for water resource management on the Clutha, with particular reference to the decision-making processes that have culminated in the building of the high dam. It critically evaluates recent experiences and comments on future prospects for resolving resource use conflicts rationally through planning for multiple utilization in a climate of market led policies of the present government.The study demonstrates the inevitable conflicts that can arise within a public bureaucracy that combines dual responsibilities for policy making and operational functions. Hitherto, central government has been able to manipulate the water resource allocation process to its advantage because of a lack of clear separation between its two roles as a policy maker and developer. The conflicts that have manifested themselves during the last two decades over the Clutha should be seen as part of a wider public debate during the last two decades concerning resource utilization in New Zealand. The Clutha controversy was preceded by comparable concerns over the rising of the level of Lake Manapouri during the 1960s and has been followed by the debate over the think big resource development projects during the 1980s.The election of the fourth Labour government in 1983 has heralded a political and economic policy shift in New Zealand towards minimizing the role of public intervention in resource allocation and major structural reforms in the relative roles of central and regional government in resource management. The significance of these changes pose important implications for the future management of the Clutha.     

应用高频气力分选机分选电子废料碎片的研究

进行了实验室高频气力分选机分选3～0.3 mm印刷电(线)路板模拟物料的研究.结果表明,在振频为1 621次/min,上升风量为120 m3/h,95 m3/h,60 m3/h,床面横向倾角6.64°,纵向倾角为1.07°时,金属回收率达93.95%;重产物金属品位为89.19%;轻产物中非金属的品位达99.33%.0.5～0.3 mm细粒物料的分选效果也是令人满意的.     

中国加油站VOC排放污染现状及控制

应用排放因子法估算了2002年度全国加油站VOC的排放量.在综合考虑经济,社会,人口等各方面因素后,通过调整现有的活动水平估算了未来20a内全国的燃油消耗情况,以及VOC排放的增长趋势.结果表明:2002年我国加油站VOC排放量为187.6×10³t,由此造成的经济损失达到了7.5×10⁸元人民币.在维持现有控制水平情况下,到2030年VOC排放量将达到1196×10³t,经济损失高达47.8×10⁸元人民币.比较了StageⅠ、StageⅡ油气回收系统以及ORVR的回收效率和成本,并对其可行性和经济适用性进行分析.结果表明:这3种回收技术的引进将会大规模的消减加油站VOC的排放,并且选择性的措施组合能够取得更好的效果.相对于StageⅡ回收系统,ORVR的效率更高费用更低.但是ORVR的引进需要比StageⅡ更长的时间,为了达到80%的普及率至少需要11a左右.为在短期内达到一定的控制要求,可优先考虑StageⅡ回收技术;但是从长期的环境和经济效应来看,ORVR才是最终的选择.     

电极构型对空气阴极生物燃料电池发电性能的影响

在空气阴极生物燃料电池(ACMFC)中,从阴极扩散进入阳极的氧气能够被兼性微生物作为电子受体还原,进而导致电子损失严重.本研究利用葡萄糖作底物,对2种不同电极构型的空气阴极生物燃料电池ACMFC1和ACMFC2的功率输出和电子回收进行了比较研究.结果表明,ACMFC1的内阻为302.14Ω,阳极电位为-323mV,最大功率密度为3 070 mW/m³;ACMFC2的内阻为107.79Ω,阳极电位为-442mV,最大功率密度达到9 800 mW/m³.在间歇条件下,ACMFC2可以连续运行220h,电子回收率为30.1%;而ACMFC1只能运行不到50h,电子回收率为9.78%.因此,合理的设计空气阴极生物燃料电池电极构型可以减小内阻,增大电池电动势进而增大功率输出,提高电子回收率.     

回收法氧化镁湿法烟气脱硫机理和工艺基础研究

以氧化镁浆液作为吸收液,对空气与SO₂混合气的鼓泡吸收做了全过程的实验观察.测试分析表明,在高效而稳定的脱硫过程中,吸收液的酸化是由HSO₃^-所致;酸化趋势与SO₂水解规律相一致,由初期高pH值下SO₃^2-为主的缓变到低pH值下HSO₃^-为主的剧变;吸收液温度对脱硫率的影响不敏感;MgSO₃相对高的溶解度和易氧化性及MgSO₄良好的水溶性保持了MgO脱硫的高效率(>98%)和高利用率.燃煤烟气脱硫工业试验确认了MgSO₄经吸收液循环可提浓至实验温度(40～50℃)下的饱和浓度而不产生有害影响,脱硫率因脱硫活性物质的富集反而提高,从而显示出回收工艺的技术经济可行性.     

撇油器的原理及性能

溢油回收装置的有效使用是降低和消除溢油污染的重要手段。比较了撇油器的各种原理、性能及操作条件。     

废催化剂中金属组分回收利用概述

废催化剂中金属组分的回收利用具有经济性和环保性,从工程项目开发的角度,对废催化剂中金属组分回收利用技术与经济等方面的问题进行了概述,主要包括废催化剂原料的收集与分类、回收技术方案选择、经济评价及关键理论,同时也指出了相关问题及发展前景。