错列不等直径双圆柱绕流特性数值研究

为研究低亚临界雷诺数Re情况下错列角度θ对不等直径双柱体绕流特性的影响,利用Fluent软件模拟了Re为3 900、间距比G/D为2.0、直径比D/d为0.5、θ=0°~180°之间9种角度的绕流过程,得到了流场涡量图、斯特鲁哈数St_1和St_2、平均阻力系数C_(d1)和C_(d2)以及平均升力系数C_(l1)和C_(l2)。研究结果表明,随着θ的从小到大,St_1先增大后减小,且在θ=30°和180°时有两个值,St_2在θ=120°~150°时明显小于其它角度;C_(d1)和C_(d2)的整体趋势都是先增大后减小,C_(l1)在θ=150°时取得极大值,C_(l2)在θ=30°时取得极小值。θ=0°时,两柱后方有单一涡脱落形态;θ=30°时,小柱后方有稳定漩涡脱落产生,大柱后方涡脱落受到干扰,且大柱有两个涡脱落频率;θ=45°~90°时,在间隙流的作用下,两柱后方均有漩涡脱落,尾流中有两列涡街;θ=120°~180°时,大柱后有稳定漩涡脱落,小柱涡脱落受到抑制。研究结果可为相关海洋工程设计提供参考。     

Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27

In this study, individual Japanese flounder were intraperitoneally injected with 2 μg tributyltin-d27 (TBT-d27) fish⁻¹. Blood samples were collected on day 7 after injection. TBT-binding protein types 1 and 2 (TBT-bp1, -bp2) in the blood serum were quantified by western blotting analysis. As a result, the concentration of TBT-bp2 in TBT-d27 treated group increased to 220% of that in the solvent control, whereas the TBT-bp1 concentration decreased to 65% of that in the solvent control. Additionally, a positive relationship between the concentrations of TBT-bp2 and TBT was observed in blood sera of wild and cultured flounder. We suggest that TBT-bp2 is produced in response to TBT exposure and may play an important role in fish physiology.     

A DEM-based evaluation of potential flood risk to enhance decision support system for safe evacuation

A practical, DEM-based practical method is proposed to enhance flood risk management in fluvial areas by quantifying relative risk as a function of vulnerability to inland and evacuation difficulty. Both measures are based mainly on the topography of the region, so the method does not require detailed data on the physical characteristics of the land. First, we use the deterministic 8-node method on a digital elevation map (DEM) to trace storm waterways. Second, we repeat the process on a reversed DEM to trace evacuation routes that avoid the waterways and zones dangerously close to the rivers. Finally, on the basis of such two flow lines of evacuee and storm water, we proposed the protocol to evaluate the flood risk at every point on the map taking into account both the minimum time required for floodwater to arrive and duration of an evacuation from that location. The time that must be allocated for safe evacuation is defined as the potential flood risk of evacuation (PFRE). The method is demonstrated on a fluvial area of the Kaki River in Nagaoka city, Japan. In addition, we illustrated the application of the PFRE map to divide the region into areas of greater or lesser evacuation urgency.     

Performance of dry-separation processes in the recovery of cenospheres from fly ash and their implementation in a recovery unit

Cenospheres recovery is one of the coal fly ash beneficiations, providing economic as well as environmental benefits. Current techniques, such as lagoon or other wet-separation processes, consume large amounts of water and add to water pollution due to leaching of toxic materials from fly ash. The other possible disadvantage is the need for a wide operational area, which is unsuitable for densely populated countries. As wet-separation processes have some disadvantages, an improved and/or sustainable alternative recovery technique is required. An air classifier is one of the alternative techniques. In this study, two types of air classifiers, namely a closed-type pneumatic separator and a micron separator, have been investigated. In terms of separation efficiency, it was found that the micron separator has the potential to be applied in cenospheres recovery from coal fly ash, giving a Newton's efficiency of 0.44, as compared to a value of about 0.26 for the closed-type pneumatic separator. The cenospheres recoveries of both pieces of equipment at their optimum Newton's efficiencies were similar at over 60 wt.%. The separation performance was further assessed from the particle distributions of the overflow and underflow products obtained from both pieces of equipment, as well as from SEM images. It was found that the lower Newton's efficiency of the closed-type pneumatic separator was due to the re-concentration of fine particles in the underflow product at air-flow rates higher than 2.2 m/s (the underflow product yield was about 55 wt.%).In order to further confirm the applicability of this technique, the micron separator, which had provided higher separation efficiency and cenospheres recovery, was deployed in a cenospheres recovery unit prior to the use of a wet-separation process (float and sink tank). About 80% of the cenospheres was recovered, with an 87.8% reduction in the total mass of fly ash to be separated in the float and sink tank. Consequently, much less water was needed for the process of cenospheres recovery. Moreover, it was also confirmed that the micron separator could yield higher quality fly ashes, that is, fly ash types I and II, from lower feed quality of fly ash type IV, which is the lowest category in commercial classification of fly ash according to JIS A6201.     

In situ observation of a garnet/perovskite transition in CaGeO<Subscript>3</Subscript>

We used an in situ measurement method to investigate the phase transition of CaGeO₃ polymorphs under high pressures and temperatures. A multi-anvil high-pressure apparatus combined with intense synchrotron X-ray radiation was used. The transition boundary between a garnet and a perovskite phase at T = 900–1,650 K and P = 3–8 GPa was determined as occurring at P (GPa) = 9.0−0.0023 × T (K). The transition pressure determined in our study is in general agreement with that observed in previous high-pressure experiments. The slope, dP/dT, of the transition determined in our study is consistent with that calculated from calorimetry data.     

西藏班戈县东嘎花岗岩体特征及锡找矿前景分析

东嘎花岗岩体位于冈底斯一念青唐古拉板片北缘、班公错一怒江结合带中段班戈一崩错板片。岩体时代为燕山晚期,属印度一欧亚板块碰撞造山构造环境。岩石属富钠、硅铝过饱和类型,该岩体位于斑戈一嘉黎一波密一察隅锡成矿远景带内,岩浆分异程度高,具有S型花岗岩体的典型特征,与滇西、川西含锡花岗岩体特征相似,成矿条件有利。区域化探资料显示锡异常明显,异常为Sn、Rb、Y、u、Nb、Ag、w、Th、Pb等多元素组合。sn元素的强度高、规模大。据区域地质、岩石化学及地球化学特征及区域成矿资料,东嘎花岗岩体具有良好的锡成矿前景。     

Urban mapping,accuracy, & image classification: A comparison of multiple approaches in Tsukuba City,Japan

The rapid growth of urban space and its environmental challenges require precise mapping techniques to represent complex earth surface features more accurately. In this study, we examined four mapping approaches (unsupervised, supervised, fuzzy supervised and GIS post-processing) using Advanced Land Observing Satellite images to predict urban land use and land cover of Tsukuba city in Japan. Intensive fieldwork was conducted to collect ground truth data. A random stratified sampling method was chosen to generate geographic reference data for each map to assess the accuracy. The accuracies of the maps were measured, producing error matrices and Kappa indices. The GIS post-processing approach proposed in this research improved the mapping results, showing the highest overall accuracy of 89.33% as compared to other approaches. The fuzzy supervised approach yielded a better accuracy (87.67%) than the supervised and unsupervised approaches. The fuzzy supervised approach effectively dealt with the heterogeneous surface features in residential areas. This paper presents the strengths of the mapping approaches and the potentials of the sensor for mapping urban areas, which may help urban planners monitor and interpret complex urban characteristics.     

中巴地球资源卫星在辽东区域环境监测中的应用评价研究

对中巴资源一号卫星 CCD传感器接收的辽宁省营口幅数据 ,从几何精度、空间分辨率、数据噪声等方面 ,进行了图像数据质量评价 ,认为从总体上讲 ,达到了设计要求 ,具有广阔的应用前景 ,同时指出 ,CCD传感器在稳定性和同一性方面尚需改进     

基于遥感的江苏省区域建设用海集约利用现状评价

区域建设用海是海域使用的一种重要方式。文章以土地与海域集约利用评价为参照,从"投入—产出"的角度出发构建了区域建设用海集约利用评价指标体系,利用遥感解译方法从2017年高分影像中提取并计算了江苏省12个区域建设用海的主要评价指标值,应用TOPSIS模型评价了江苏省沿海已建项目的集约用海现状。研究表明:①江苏省区域建设用海开发利用程度较低,53.2%的土地处于未利用状态,农渔业为面积占比最小的用地类型,江苏省对第二、第三产业的发展更为重视。②已有的开发活动中,人工设施面积较小,建筑与道路等面积占比远小于生态面积,区域生态健康状况良好。③根据指标计算,江苏省区域建设用海集约利用评价得分集中在0.4～0.6,集约利用程度整体较低,不同项目集约化利用程度差异较小,主要原因在于项目投资强度两极分化,道路等基础设施不够完善等。④从不同用海类型来看,交通运输用海集约利用程度最高,其用海结构布局最适宜,效率最高。文章所建指标具有指向性,应用TOPSIS模型进行无须赋予权重,因此更能客观真实地反映江苏省区域建设用海的集约利用情况。