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131.
为了对毒气扩散过程进行及时、有效的模拟,将开源计算流体动力学软件OpenFOAM与PISO算法(pressure implicit with splitting of operators,压力隐式算子分割算法)相结合,进行城市街区毒气扩散模拟研究. 将SIMPLE(semi-implicit method for pressure linked equations,压力耦合方程组的半隐式算法)与PISO算法进行了对比,指出以PISO算法为基础的数值模拟在城市街区这类大范围毒气扩散模拟中具有容差性强、计算较为稳定等优点. 以福州大学怡山校区为扩散区虚拟地理环境,选用氯气为假定毒气,利用OpenFOAM对氯气的扩散传播过程进行了模拟, 并与商用软件FLUENT在相同条件下的ρ(Cl2)模拟结果进行了对比. 结果表明,结合PISO算法的OpenFOAM能够较好地完成复杂虚拟地理环境下的毒气扩散过程模拟,其ρ(Cl2)模拟结果与FLUENT模拟结果的平均偏差小于5%,但在计算效率上却提高了41.89%. 相似文献
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石油类污染物在包气带中的迁移预测——以兰州西固商业石油储备库为例 总被引:2,自引:0,他引:2
包气带在地表石油类污染物下渗到地下水的过程中扮演着重要角色,同时包气带受到污染必然会对周围环境,特别是植物的生长造成影响,从而影响人类自身。主要使用HYDRUS软件预测了兰州西固商业石油储备库的渗漏对包气带的影响,分正常工作状况和非正常工作状况两种情况。在正常工作状况下,从5000天到10000天,污染物浓度呈线性增加,到50年左右,包气带底部(下边界)污染物浓度接近0.1mg/cm3。在非正常工作状况下,包气带底部(下边界)浓度增加的速度要远远大于正常工作状况,到50年左右,包气带底部(下边界)浓度达0.5mg/cm3。预测结果可以为相应工作状况下饱和带的溶质迁移模型提供参考依据,对确定饱和带污染物的浓度具有重要的参考意义。 相似文献
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Establishing Representative No-Take Areas in the Great Barrier Reef: Large-Scale Implementation of Theory on Marine Protected Areas 总被引:17,自引:0,他引:17
LEANNE FERNANDES JON DAY ADAM LEWIS SUZANNE SLEGERS BRIGID KERRIGAN DAN BREEN DARREN CAMERON BELINDA JAGO JAMES HALL DAVE LOWE JAMES INNES JOHN TANZER VIRGINIA CHADWICK LEANNE THOMPSON KERRIE GORMAN MARK SIMMONS BRYONY BARNETT KIRSTI SAMPSON GLENN DE'ATH BRUCE MAPSTONE HELENE MARSH HUGH POSSINGHAM IAN BALL TREVOR WARD KIRSTIN DOBBS JAMES AUMEND DEB SLATER KATE STAPLETON 《Conservation biology》2005,19(6):1733-1744
Abstract: The Great Barrier Reef Marine Park, an area almost the size of Japan, has a new network of no-take areas that significantly improves the protection of biodiversity. The new marine park zoning implements, in a quantitative manner, many of the theoretical design principles discussed in the literature. For example, the new network of no-take areas has at least 20% protection per "bioregion," minimum levels of protection for all known habitats and special or unique features, and minimum sizes for no-take areas of at least 10 or 20 km across at the smallest diameter. Overall, more than 33% of the Great Barrier Reef Marine Park is now in no-take areas (previously 4.5%). The steps taken leading to this outcome were to clarify to the interested public why the existing level of protection was inadequate; detail the conservation objectives of establishing new no-take areas; work with relevant and independent experts to define, and contribute to, the best scientific process to deliver on the objectives; describe the biodiversity (e.g., map bioregions); define operational principles needed to achieve the objectives; invite community input on all of the above; gather and layer the data gathered in round-table discussions; report the degree of achievement of principles for various options of no-take areas; and determine how to address negative impacts. Some of the key success factors in this case have global relevance and include focusing initial communication on the problem to be addressed; applying the precautionary principle; using independent experts; facilitating input to decision making; conducting extensive and participatory consultation; having an existing marine park that encompassed much of the ecosystem; having legislative power under federal law; developing high-level support; ensuring agency priority and ownership; and being able to address the issue of displaced fishers. 相似文献
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Excel在水环境监测数据分析中的应用 总被引:2,自引:1,他引:1
针对水环境监测数据分析中常用的制图、水质类别判断、综合污染指数计算和湖库富营养化指数计算等方面,用VBA语言编写了在Excel中运行的宏,以提高环境监测数据处理时自动化水平,提高工作效率。 相似文献
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David M. Hetrick Andrea L. Sjoreen 《Journal of the American Water Resources Association》2004,40(5):1129-1140
ABSTRACT: Hydrologic Transport Assessment System (HYTRAS) is a software package that models contaminant transport in rivers and streams, including volatilization, adsorption/desorption, sedimentation, settling, and resuspension. Biodegradation, photolysis, and any other process that can be modeled using a first‐order decay constant can be included as well. HYTRAS originally modeled the transport of radionuclides and has recently been expanded to include transport of chemicals. The transport of chemicals has been validated using data from an accidental release of the chemicals disulfoton and thiometon into the Rhine River in 1986. For these chemicals, sorption is not an important process. For the range of measured flow velocities, HYTRAS was found to bound the peak arrival times. For the range of measured degradation rates, HYTRAS was found to bound the peak concentrations within 400 km of the source and bound the peak concentrations within a factor of two out to 700 km. 相似文献
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为确保处置抢险救灾、应急救援等突发性事件通信联络畅通,本文采用模块设计思想,结合32位ARM7TDMI(-S)(Advanced RISC Machines)单片机,完成了一种不同频率无线通信电台间串行数据信息交换控制的软件系统设计。实现了数据信息自动存储转发和最佳传输信道选择,接收端直接打印输出,可提高通信效率5-6倍。 相似文献