Movement of smallmouth bass within the Beaver Island Archipelago, northern Lake Michigan

Fish movement may vary across a wide array of aquatic ecosystems and may be related to the overall size of the system inhabited. We investigated movement of smallmouth bass in Lake Michigan because this information is lacking for larger systems. A total of 16 smallmouth bass were surgically implanted with ultrasonic transmitters within the Beaver Archipelago, northern Lake Michigan. During 2007-2008, a maximum of one location per individual was recorded daily during three specific tracking periods - pre-spawn, spawning, and post-spawn - to determine diurnal movement patterns. Movement was evaluated as site fidelity, minimum displacement rate, maximum excursion rate, and distance from shore. Smallmouth bass exhibited greater maximum excursion rates during the spawn period compared to pre-spawn. Movement rates did not differ between tracking periods; however, movement rates were greater during the spawn period in 2007 than 2008. Both sexes moved further offshore to deeper water during post-spawn, but females were located further offshore than males during this period. Annual site fidelity was more evident during post-spawn than during spawning for both sexes. Two smallmouth bass emigrated outside of the Archipelago, suggesting this population may be more “open” in terms of individuals moving throughout northern Lake Michigan than previously thought. These results indicate smallmouth bass may move greater distances in larger aquatic systems and therefore larger management units (in terms of total area) should be established in Lake Michigan to account for these greater excursion distances.     

静压法油罐计量系统在油库的应用

对静压法计量系统在油库中的应用做了说明,该系统运行稳定可靠,加强了罐内油品的管理及液面控制,可降低劳动强度,经济效益显,并从讲理原理、系统构成和计量精度等方面进行了详细的介绍。     

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近年来,二甲醚作为重要化工原料及清洁燃料,进一步法合成技术发展迅速。与两步法相比,二甲醚一步法生产成本的降低为其使用范围的扩大奠定了基础。本文阐述了二甲醚一步法全两步法合成在热力学上的优势来源于多个化学反应同时进行所产生的协同效应。热力学上的优质直接导致了原料合成气转化率的提高。综述了两种一步法二甲醚合成技术（浆床合成技术和固定床合成技术）的发展情况。对以NKK和Haldor Topsφe A/S两公司为代表的这两种技术的进展及工业化进程进行了描述,还就这两种技术对合成气组成及造气工艺的不同要求进行了初步探讨。针对不同造气工艺的不同适应性,最后对不同市场需求情况下所宜采用的二甲醚生产一步法工业化方案进行了评述。     

Galactose concentration in pizza cheese prepared by three different culture techniques

A study was conducted to determine the most suitable lactic culture combinations and the techniques for the preparation of low moisture part skim (LMPS) mozzarella cheese (pizza cheese) with a low level of galactose. The cheesemaking time tested for all 12 culture combinations was less than 3 h and hence was found suitable for pizza cheesemaking. The initial accumulated galactose concentration was lower in unstretched curd followed by no-brine curd and stretched curd in ascending order. During storage of the cheese for 7 days, the galactose percentage in the cheeses prepared using cultures comprising galactose-fermenting strains of Lactobacillus helveticus and Streptococcus thermophilus was 0.30 in stretched curd, 0.04 in unstretched curd and 0.03 in no-brine curd. The degree of reduction in the level of galactose in pizza cheese during storage was maximum with the no-brine curd technique followed by the unstretched and stretched curd techniques in that order. This study provides information regarding selection of starter culture combinations and techniques for pizza cheesemaking based on consumer preference for low or moderate browning mozzarella cheese as a result of its galactose concentration.     

龙首矿采矿装备简述

龙首矿自建矿以来,根据生产实际,合理地选择了各种相关设备。随着生产的发展,对有些设备又进行了更新、改造,在实现矿山机械化、自动化方面取得了显著成绩。本文对该矿各工艺环节所用设备进行了详细介绍,并指出了目前所达到的水平。     

Wind energy for the 1990s and beyond

Electrical power must be available to the consumer in any amount upon demand. Conventional methods of power generation, such as the burning of fossil fuels, hydroelectric plants, and nuclear power plants, have considerable shortcomings. Governmental regulations have increased in quantity and have raised the already rigid standards of producing electric power without further damage to the environment. Electrical power produced by wind energy conversion systems are undergoing extensive research and revitalization as a viable solution to clean air power generation. The basic challenge to scientists and engineers is to develop wind energy conversion systems that produce adequate amounts of power, but at a cost comparable to present conventional methods. This article discusses the background and impact of the modern wind energy conversion system on future power generation.     

浅谈高速公路弃土（石、渣）场选址及水土保持措施配置

根据高速公路水土流失特点,从弃土（石、渣）场选址及水土保持措施等方面进行探讨研究,为高速公路弃土（石、渣）场水土流失防治提供技术依据。     

废碱液装置布置设计探讨

通过介绍工艺流程,探讨了装置布置防火设计规范执行、火灾危险性分类、对周边设施防火间距确定以及按不同危险性设备集中分区设计的方法。结合工程特点和装置散发臭味的特点,废碱液装置应位于居民区全年最小频率风向的上风侧,并与周边居民居住区设置一定的卫生防护距离,探讨了季风向玫瑰图选取的方法和卫生防护距离计算方法。     

XG─泥浆固化剂在井场的实际应用

以两种不同的施工作业方法,在三口井上进行了XG—固化剂现场废泥浆固化施工试验,为钻井施工后的环境保护工作找到了一项较成熟的技术,试验中所提供的两种施工方法,可供不同的现场条件选择。     

管道金属波纹补偿器的选用及安装

金属波纹补偿器在大直径管道中得到了广泛地应用。在设计时,需合理设定固定支架,将管道系统分割成简单的、可独立膨胀的管段;施工安装时,应采取可靠措施保护波纹管,勿使其受损。