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1.
Livelihood diversity factors such as flexibility within fisheries, geographical mobility, reallocation of fishing effort into the broader economy, and the non-material benefits that fisheries provide are important areas of research in marine policy. We use two small-scale fisheries related socio-economic surveys of communities in the Tigak Islands of Papua New Guinea. The first conducted 5 years before a ban on the harvesting of sea cucumbers was imposed and the second from the present day, 5 years after the initiation of the ban—with the objectives of exploring changes in household fishing strategies (types and numbers of species targeted) and to identify any important socioeconomic factors that help explain those changes. Fishing's contribution to total household income has increased significantly (p = 0.019) up from 61% in 2004 to 73% in 2014 with the percentage of female residents living in a household now positively and significantly (p = 0.018) associated with fishing income. The average number of species categories targeted per household increased insignificantly while households with more women are significantly (p = 0.018) less likely to target more species than households with more men. Moreover, customary management practices contribute to this difference. Together, these results show that households are not worse off financially 5 years after the ban on sea cucumber harvesting and that gendered seascape use has implications for the role of livelihood diversity as a marine policy tool.  相似文献   
2.
Since 1992, coastal researchers at the University of North Carolina at Wilmington have been documenting the impacts of human recreational use on Masonboro Island, a component of the North Carolina National Estuarine Research Reserve, and the subsequent natural processes that mitigate these impacts. Both short-term and long-term natural mitigational processes were identified. The effects of these processes were found to be much more rapid than similar impacts on typical terrestrial settings. However, careful examination of the data suggests that both physical location of the impact site and natural variability of weather patterns and events play a role. Management implications of these findings are proposed.  相似文献   
3.
The hot stamping process has been used in the automotive industry to reduce the weight of the body-in-white and to increase passenger safety via improved crashworthiness. However, defects such as fracture and wrinkle occur when hot stamping is performed using a conventional drawing or forming method. In this study, a channel-type indirect blank holder (CIBH) is proposed to develop a high-strength center pillar in form-type hot stamping, so that the aforementioned drawbacks are overcome. This type of blank holder plays an important role in reducing severe wrinkling at the flange; such wrinkling leads to folding after the completion of form-type hot-stamping. First, we investigated the effect of the channel shape on the indirect blank holding force by using a simplified two-dimensional plane-strain stamping process. Second, we selected the slope angle and corner radius of the channel as the main shape parameters by finite element analysis and artificial neural network (ANN). It is known that fracture at the hot formed wall and wrinkle at the flange are significantly affected by the slope angle of the channel, and the appropriate value for eliminating fracture and wrinkle is determined to be 99°. By performing hot stamping using a form die with the selected channel, we can manufacture a high-strength center pillar without wrinkle and fracture.  相似文献   
4.
The objective of this paper is to improve the performance estimation model of the internal flow field of a torque converter. Compared with performance experiment results, the converter based on the one-dimensional model does not satisfy the performance requirements demanded in practice. Therefore, we need to develop more predictable and reliable performance estimation models. In order to obtain shape information on three-dimensional blade geometry, a process of reverse engineering conducts a torque converter assembly, impeller, turbine and stator. In addition, a CFD simulation including mesh generation and post-processing was carried out to extract equivalent parameters from the internal flow field. The internal flow field can be explained by analyze the correlation between a performance estimation model and CFD analysis. The equivalent performance model adopts the variation of energy loss coefficients for a given operating condition according to the application of a changing energy loss coefficient by the least mean squares method. The estimated equivalent model improves the agreement in performance between experiments and the theoretical model. This model can reduce the error to within about 3 percent. Furthermore, this procedure for predicted performance achieves eminence in the estimation of the capacity factor.  相似文献   
5.
提出了一个在有高速公路和城市干道的组合路网中设置可变信息标志(CMS)组位置的最优化模型.与文献中现有的模型相比较,本文的模型有效地达到了实际规模道路网络计算复杂性问题和确保求解模型的质量之间很好的平衡. 本模型具有三个不同的特征:(1)认为在路网中设置安装可变信息标志(CMS)系统是一个必须同时考虑现在和未来需要和利益的典型的规划问题;(2)评估由于在路网中设置了可变信息标志(CMS)系统而带来的交通效益是通过具有不同交通分布型态的多个时段来完成的;(3)考虑了在不同的路段上和时段内交通事件的特征本质上是变化的因素.本文还进行了敏感性分析,用以检验在各种不同的交通输入参数中,如交通需求、交通事件特征值、以及驾驶员交通行为的不确定性对可变信息标志系统(CMS)在路网中的最优设置的潜在影响.最后,本模型应用于加拿大多伦多的401高速公路和辅道组成的混合道路系统,并且对CMS系统设置结果进行了检验.  相似文献   
6.
为确保内河电子航道图在传输过程中的安全性和完整性,针对内河管理的特点提出一套内河电子航道图数据保护方案.方案基于现代加密技术和数字签名技术,在数据提供商、设备制造商和数据用户三方相互鉴别、相互认证的条件下实施,通过用户权证和江图权证来鉴别用户身份和传递密钥,并设计了用户端数据处理流程.应用结果表明,该方案有效、安全.  相似文献   
7.
注汽管道承压能力评估和实物试验验证   总被引:2,自引:2,他引:0  
基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。  相似文献   
8.
一种新型凝汽器铜管污垢状况在线监测仪   总被引:3,自引:2,他引:1  
目前 ,火力发电厂凝汽器大多采用定期清洗。提出了一种通过污垢热阻评定凝汽器铜管污垢状况的计算方法 ,设计了基于单片机系统的污垢热阻在线测量系统 ,有助于实现胶球清洗系统的在线优化、确定最佳清洗周期。测量系统设计合理、操作方便  相似文献   
9.
报道了利用微波消化检验样品的基本原理,并介绍了利用民用微波炉,聚四氟乙烯高压罐消化样品的操作方法及最佳消化条件。经微波消化的消化液。应用原子吸收法测定其中的铅和铜,并做了回收率实验。测定结果变异系数铜:2.0%-4.5%,铅:2.5%-3.8%。回收率铜98.0%-99.0%,铅:96.0%-99.5%。  相似文献   
10.
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