不同类型油田采出水作为阳极底物对MFC电压的影响

考察水驱采出水、聚驱采出水和三元复合驱采出水3种主要油田废水分别作为阳极底物时对3组微生物燃料电池(MFC)输出电压的影响及影响因素,考察采出水中主要难降解有机物的去除效果。结果表明,使用成分更为复杂、COD值高的聚驱采出水和三元复合驱采出水作为阳极底物的MFC产生的电压较大,可达到647和570 mV,水驱采出水最小,为270 mV;一个运行周期内,随着反应进行3个微生物燃料电池的阴极电势相对稳定,阳极电势有明显升高趋势,输出电压的变化主要来自阳极的贡献。阳极底物的COD去除效果和库伦效率均对阳极电势产生影响。其中,微生物燃料电池对废水中表面活性剂的去除效果最好,在进水浓度为67.8 mg/L时,出水浓度为2.1 mg/L,去除率达到96.90%;不同采出水的石油和聚合物的去除效果符合MFC的输出电压和阳极底物COD值变化规律。     

渔业燃油补贴对渔业资源的影响分析及政策建议

自2006年以来,渔业燃油补贴政策的实施有效缓解了柴油价格上涨与渔民生产成本之间的矛盾,但大量补贴可能会造成捕捞努力量的上升。文章首先阐述了我国渔业燃油补贴政策的主要内容和实施现状,然后通过分析在渔业燃油补贴作用下Gordon-Schaefer模型的变动情况,说明其对渔业资源的影响。结果表明,当渔业处于自由进入的状态,渔业燃油补贴能促进渔业资源的开发利用,也可能进而导致过度捕捞的出现。如果政府对捕捞业不加以干预,只会加大渔业资源的负荷。文章最后在基于渔业资源可持续利用背景下提出了有关合理实施渔业燃油补贴政策的建议,例如调整渔业燃油补助用油系数、根据实际用油量采用阶梯型补贴标准、加强燃油补贴的宣传引导等。     

The impact of repeat spawning of males on effective number of breeders in hatchery operations

In conservation hatcheries, typically a great emphasis is placed on maximizing the effective number of breeders through spawning an appropriate number of spawners, spawning equal numbers of males and females when possible, and by mating either in a single-pair or factorial fashion. A commonly encountered problem, especially in small operations with anadromous salmonids, is a shortage of males at some point during the season, so that some males need to be spawned multiple times. This has an impact on the genetically effective number of breeders, and the commonly used equations for effective number are not applicable. In this paper I derive a relatively simple equation for effective number of breeders when some males are multiply spawned but reproductive contribution within spawning classes are equal: , where i is the number of times a male is spawned, N_i the number of males spawned i times, and μ_t the mean gametic contribution. I also derive an equation that allows relaxation of the assumption of equal contribution within classes. I then develop a number of simple and accurate approximations for the effective number of breeders. The equations can be applied to any situation in which there are discrete spawning classes in which the average reproductive contribution of any one class can be expressed as a multiple of that of another class.     

Estimating attraction areas and effective fishing areas for Chilean lemon crab (Cancer porteri) using traps

The applicability of a method, based on varing distance between traps, for estimating attraction area (A_at) and effective fishing area (A_ef), for Cancer porteri caught with experimental traps, was tested. Based on fishing experiments, where lines of traps were set with different spacing between them, the minimum distance at which A_at of adjacent traps did not overlap was estimated. This provided an estimate of A_at of 9348 m²/trap. To estimate A_ef, an exponential decay function for the probability of capture within the A_at was assumed; A_ef was estimated at 577 m²/trap, similar to values estimated for other shallow water crustaceans using SCUBA for calibration. This is inferior to estimates calibrated with underwater photography for crustaceans at greater depths.     

Ngodwana Open-root Nursery Operations Schedule as at 14.08.79

A techno-economic assessment of the potential of producer gas as an alternative fuel, taking into account local biomass availability. costs. requirements of industry and agriculture, and available technology and equipment was promising.

The approach in setting an objective and the methods of coordinating and organising the work towards establishing producer gas as a fuel in practice are given.

The success of the programme as an example of application of technology is indicated.     

固体成型燃料生产的资源承载力分析

当前森林资源和林业可持续发展的重要性及目前的严峻状况要求将可持续发展的理念深入到林业建设的各个层面,生物质固体成型燃料技术是生物质能可持续开发利用的一项重要技术,具有广阔的发展前景。笔者通过分析林区采伐剩余物利用上存在的问题,及不同采伐类型和产品类型的出材量、采伐剩余物总量等,对重点林区采伐剩余物重量进行了估算分析,阐述了生物质固体成型燃料技术在我国推广应用的可行性。     

北京八达岭林火安全影响分析

分析了与北京八达岭林场潜在林火险情密切相关的气候、地形、植被和可燃物四类因素。气候潜在林火险情主要是防火期内温度高、湿度小、风多、风大、植物凋萎期长。陡急险坡和鞍部构成防火和灭火危险地形因素。易燃针叶和阔叶树种多、林下灌木和多年生草本茂密、幼龄林和中龄林面积比例高、易燃可燃物载量大、水平和垂直分布连续性强为火险的植被因素。     

白花丹参最佳采收期研究

以山东道地药材白花丹参为试材,研究了其不同生长时期地上部与地下部干物质积累、主要有效成分(丹参酮ⅡA和丹酚酸B)含量的变化规律,综合考虑地下部干物质重与有效成分含量最大化两因素,明确白花丹参的最佳采收期为11月上旬。     

Spatial optimization of soil and water conservation practices using coupled SWAT model and evolutionary algorithm

Soil and water conservation practices have been extensively used in effective watershed management. The impact of each conservation practice is site specific and dependent on the implementation site in the watershed. In order to select cost effective placement of conservation practices with high impact, a large number of spatial combinations is needed to be compared. In this study, an optimization model framework is presented to find cost effective solutions for sediment yield and runoff control in the Fariman dam watershed in the Northeast of Iran. This was accomplished by integrating soil and water assessment tool (SWAT) for simulation of watershed hydrology and multi objective genetic algorithm (NSGA-II) for spatial optimization of soil and water conservation practices. The optimized solutions provided a trade-off between the two objective functions. The final Pareto-optimal shows that the impact of soil and water conservation practices on sediment yield is more than stream flow. The trade-offs between the objective functions show that the implementation of the median cost can lead to a significant decrease of 22.1% in the amount of sediment yield, and 10% in stream flow. Also, percent change achieved through median cost is very close to percent reduction with the highest cost. Results of low cost solution show that the vegetative practices are a suitable economic scenario for soil and water conservation. The introduced framework can be adapted as a suitable tool for selecting cost effective conservation practices in different regions.     

6300ZC型柴油机加中冷节能研究

我院与广西北海海海洋渔业公司、广州柴油机厂合作，对６３００ＺＣ型柴油机加中冷节能研究，经四年多的努力，设计、研制了二代空冷节能器样机，台架试验和实验船试用，均取得了明显节能效果，使６３００ＺＣ型柴油机性能、燃油耗率达到国内先进水平。