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251.
A transport assessment of particle-bound and dissolved artificial radionuclides (137Cs and 239,240Pu) by sea-ice and dense-water formed in western Kara Sea flaw leads close to the Novaya Zemlya dumping sites is presented in this study. We both performed a “best estimate” based on available data, and a “maximum assessment” relying on simulated constant releases of 1 TBq 137Cs and 239,240Pu from individual dumping bays. The estimates are based on a combination of (i) the content of particulate matter in sea-ice; (ii) analytical data and numerical simulations of radionuclide concentrations in shelf surface deposits, suspended particulate matter (SPM), and the dissolved phase; and (iii) estimates of lead-ice and dense-water formation rates as well as modeling results of local ice drift pathways. In the “best estimate” case, 2.90 GBq 137Cs and 0.51 GBq 239,240Pu attached to sea-ice sediments can be exported from the lead areas toward the central Arctic basin. The radionuclide burden of the annually formed dense lead water in the “best estimate” amounts to 4.68 TBq 137Cs and 0.014 TBq 239,240Pu. In the “maximum assessment”, potential export-rates of ice-particle bound 137Cs and 239,240Pu toward the central Arctic would amount to 0.64 and 0.16 TBq, respectively. As much as ≈900 TBq 137Cs and ≈6.75 TBq 239,240Pu could be annually taken up by 34.75 dense-water rejected in the lead area. Assuming the (unlikely) instantaneous release of the total 137Cs and 239,240Pu inventories (≈1 PBq and 10 TBq, respectively) from the Novaya Zemlya dumping sites into the dissolved phase, the dense lead water locally formed during one winter season could take up ≈90% of the Cs and ≈68% of the Pu released. 相似文献
252.
253.
This paper is a think piece on variations in the structure of stated preference studies when modelling the joint preferences
of interacting agents who have the power to influence the attribute levels on offer. The approach proposed is an extension
of standard stated choice methods, known as ‘stated endogenous attribute level’ (SEAL) analysis. It allows for interactive
agents to adjust attribute levels off a base stated choice specification that are within their control, in an effort to reach
agreement in an experimental setting. This accomplishes three goals: (1) the ability to place respondents in an environment
that more closely matches interactive settings in which some attribute levels are endogenous to a specific agent, should the
modeller wish to capture such behaviour; (2) the improved ability of the modeller to capture the behaviour in such settings,
including a greater wealth of information on the related interaction processes, rather than simply outcomes; and (3) the expansion of the set of situations that the modeller can investigate using experimental
data.
相似文献
John M. RoseEmail: |
254.
多洞空间小净距隧道支护结构参数量化设计与安全性分析是当前设计中的一大难题。文章针对深圳机荷高速公路荷坳隧道四洞小净距段的设计,采用总安全系数法对四洞的开挖与支护模式、各洞的开挖顺序及支护参数进行了研究比较,并采用隧规荷载-结构法、增量法、地层-结构法对支护结构的安全系数进行了对比计算,得出以下结论:(1)提出了基于总安全系数法原理的多洞空间小净距隧道设计方法;(2)根据总安全系数法得出了荷坳隧道四洞小净距段应采用“先行洞二次衬砌完成后再开挖下一孔隧道”的开挖与支护模式,且应按洞1→洞2→洞3→洞4的开挖顺序施工;(3)隧规荷载-结构法、增量法、地层-结构法虽无法得出结构的总承载安全系数,但在一定程度上可以反应部分支护结构的安全性。 相似文献
255.
机械电子技术在未来铁道车辆中的应用与发展(续完) 总被引:1,自引:1,他引:0
倾摆方式的引入显现出冰山的一角,一旦主动控制系统被铁道车辆所采用,那么引进其他主动控制系统从技术方面讲将变得越来越简单。在转向架和车体之间的倾摆系统是一种特殊的二系主动悬挂系统。因此本文接下去将探讨如何将二系主动悬挂系统进行推广,基本目的在于改善由于轨道不平顺带来的干扰,也 相似文献
256.
257.
This paper explores issues related to the electrical safety of Hybrid Electrical Vehicles (HEVs) during and after various
crash events. Japanese and American federal regulations regarding occupant protection against high voltages in Electric Vehicles
(EVs) and HEVs were surveyed and analyzed in this study. Front, side and rear impact tests for two types of HEVs were conducted
to investigate electrolyte spillage, the retention of the propulsion battery system and the electrical isolation of the occupant.
The test results met the related criteria. The test procedures and the criteria for occupant protection established through
this study were amended to Korean Motor Vehicle Safety Standard (KMVSS) No. 91 to add the crash protection of the EVs and
the HEVs. 相似文献
258.
M. S. Han S. O. Bang J. U. Cho S. Lee C. Cho 《International Journal of Automotive Technology》2013,14(1):61-66
The need for composites has been increasing in various industries because composites have good mechanical properties for their weight and superior stiffness and strength. The composites addressed in this study were multi-pore aluminum foam with a specific gravity of 1/10 composed of solid aluminum metal. This composite has excellent impact energy-absorption capability. In this study, impact tests on an aluminum foam core sandwich composite with a porous core were conducted to examine its mechanical properties. The specimen was a sandwich structure with an aluminum foam core, and different impact energies, such as 50J, 70J, and 100J, were applied to the specimen. Consequently, a maximum load of 5.5 kN occurred when the striker penetrated the upper face sheet in all experiments. The maximum load occurred at 4.2 ms for 50J, 3.5 ms for 70J, and 3.0 ms for 100J, indicating that the greater the impact energy was, the shorter the time was until the maximum load. After the maximum load occurred, that is, after the penetration of the upper face sheet, the striker penetrated 10 mm further, causing the core to be damaged in the 50J test, while the lower face sheet remained intact. In the 70J test, the striker penetrated the core and caused damage to the upper face sheet at 10 ms. Finally, in the 100J test, the striker penetrated both the upper face sheet and core and even the lower face sheet at 10 ms. Given the result above, the maximum load occurred when the striker penetrated the upper face sheet and the sandwich composite with aluminum foam core; the load then gradually decreased and then rapidly increased when the striker reached the lower face sheet, and the maximum load lasted slightly longer than the time required for the upper face sheet to be penetrated. 相似文献
259.
级配曲线是由富勒模型中最大粒径和形状系数两个参数来确定的,富勒模型能够很好地拟合使用性能良好的级配.级配曲线图是由形状系数和最大粒径组成的直角坐标系,它可以表示出级配范围、砂石比和相关的性能参数.该文分析了Superpave沥青混合料力学和水稳性能的试验结果,提出了根据级配曲线推荐的集料设计出满足路面各项性能的自由设计理念. 相似文献
260.
该文进行了一个三维有限元参数量化的粘弹性路面响应研究,由于不同的轮胎配置:双轮和宽基轮胎在3种温度(5、25和40℃)和两种速度(8、72 km/h);还有影响路面响应的3种因素:移动车轮荷载幅值(连续,梯形),层间界面条件(简单的摩擦和粘弹性模型)和横向力共同对路面响应的影响进行了研究.研究发现连续加载幅值,不但可以模拟路面对运动轮荷载的响应,并且是一种比目前使用的梯形荷载幅值更准确的研究模型.粘弹性模型极大地提高了双轮胎对预测路面的响应,而简单的摩擦模型更接近宽基轮胎的实地测量.侧向剪力是积极改善预测轮底的表面磨损和底部热拌沥青(沥青)基层的较小程度上的应变.研究表明:使用连续加载幅值和非均匀压力分布模拟移动轮,侧向剪切力和适当的界面摩擦可显著改善有限元模型对车辆加载路面响应的预测能力. 相似文献