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1.
The denitrifying woodchip bioreactor is designed to remediate nitrate-rich water, including those produced from aquaculture effluents. Reuse of treated bioreactor outflows in recirculating aquaculture would offer considerable water savings and valuable alkalinity recuperation. However, such bioreactors may leach detrimental wood-bound contaminants, preventing outflow reuse. To determine water reuse potential, woodchip media from two hardwood species (white ash, Fraxinus americana; Norway maple, Acer platanoides) were evaluated for 206 d under a range of operating conditions (start-up, steady-state, reducing conditions, and drying-rewetting cycles) for a spectrum of potentially harmful dissolved contaminants. Aerated outflows also were evaluated for acute and chronic toxicity to the biologically sensitive invertebrate Ceriodaphnia dubia. Dissolved metal leaching subsided within the first few weeks of operation, though initial concentrations of copper and zinc were detected at concentrations of concern. Elevated concentrations of tannins-lignin and total ammonia nitrogen were detected throughout the study and were influenced by operational phase. Acute toxicity was not generally detected, though chronic toxicity was observed during drying-rewetting cycles in the maple outflows. The measured toxicity was not correlated with water chemistry, indicating an additive effect of several toxicants. Overall, significant differences in outflow water quality between ash and maple wood species were negligible. Results indicated that bioreactor outflows may be applicable for aquacultural reuse, though reusing outflows immediately following start-up or restarting after a dry period would not be recommended. 相似文献
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The aim of this research was to evaluate a passenger seat of a new type bus in terms of eomfort. A fuzzy set model of multistage comfort scale (MCS) was adopted to the assessment of comfort, together with the techniques of human backshape and EMG measures 相似文献
3.
Abstract – The reproductive biology of three species of rainbowfish (Melanotaeniidae) in northeastern Australian rainforest streams was investigated. Two species, Melanotaenia eachamensis and Cairnsichthys rhombosomoides are endemic to the area, whereas the third, M. splendida splendida, is more widespread. The species were all highly fecund, producing many hundreds of eggs between 1.10 and 1.24 mm in diameter. Melanotaenia eachamensis was the most fecund, produced the largest eggs of the three species, and consequently exhibited the greatest maternal investment (as measured by gonadosomatic index). The majority of reproductive effort occurred during the dry season, although reproductively active fish were present year-round for each of the species, but particularly so for M. s. splendida and C. rhombosomoides. No evidence for a role by temperature or photoperiod as environmental cues for reproduction was found, and it was suggested that gonad development was strongly tied to somatic growth. The concentration of reproduction to the dry season ensures that larvae are produced during a period of relatively stable and benign physical conditions. Comparison of temporal changes in gonadosomatic index values suggest that the spawning season of M. eachamensis , which occurs in high-elevation streams, is more restricted and commences about 1 month earlier than either other species. A similar phenology was observed for the M. s. splendida population found at high elevation and highlights the potential for spatial differences in stream productivity to influence life history. Note 相似文献
4.
提出了一种在线测量混炼胶粘度的新方法.该方法以模糊建模技术为基础,综合考虑混炼过程各因素对胶料粘度的影响,建立起胶料粘度的在线测量模型.在模糊建模中,采用T-S模型描述胶料粘度变化的非线性过程,提出了一种基于相似性判别的模糊聚类算法以自动确定合适的聚类组数目,并用实数编码的遗传算法优化全局参数,从而获得了规则简化的、具有较高精度的模糊模型.根据此方法,设计了测量装置,并进行了现场试验.试验结果表明模糊模型输出与实验室测量值基本一致,平均误差较低且最大误差未超过1门尼.该方法较大地提高了橡胶混炼的生产效率,为粘度最优控制奠定了基础. 相似文献
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探讨了汽车无级变速器控制的关键技术之一———汽车起步离合器的控制技术,并针对汽车起步时条件的多样性以及驾驶员意图的不确定性,研究了适用于复杂条件的模糊控制算法.在离合器的滑磨阶段,把动态跟踪发动机转速的油压作为控制目标,离合器结合的控制便转化为一闭环控制.结果表明汽车能在任意工况下平顺快速起步.因此,本研究为控制CVT(Continuously Variable Transmission)起步离合器这种时变、非线性系统提出了一种简单可行的解决方法. 相似文献
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Atsushi NAKAMURA Kenji TOGASHI Naoyuki YAMAMOTO Akiko NISHIURA 《Animal Science Journal》2002,73(3):175-184
In order to control rates of response and inbreeding, mate selection using fuzzy selective mating criteria (FMC) was investigated in adult multiple ovulation and embryo transfer nucleus schemes for dairy cattle. Stochastic simulation was used to model the closed nucleus scheme. This mate selection was examined in four alternative mating and male selection schemes: (i) a hierarchical scheme; (ii) a hierarchical sibship scheme (two males per sibship); (iii) a factorial scheme (two sires per dam); and (iv) a factorial sibship scheme (two males per sibship and two sires per dam). Genetic response and inbreeding rate tended to be reduced by increasing the trade-off parameter of FMC between the expected breeding value and inbreeding of progeny. Inbreeding rates in all schemes were reduced by reducing the variance of family size through selection and the average coancestry of mating pairs through mate allocation. 相似文献
9.
建立了湖北省分地区水灾损失灾度等级的划分标准。基于模糊模式识别理论,按最大隶属原则和择近原则对灾度等级进行了模糊综合评判。 相似文献
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