一种新型水文观测设备──ASSM-Ⅱ型声学悬浮泥沙观测系统

地球上许多大河流的河水中都夹带有大量泥沙，这些泥沙在河道、河口沉淀淤积，给航道、河口的通航带来阻碍和威胁，我国的几条大河的泥沙迁移量相当惊人，因此，在港工、航道、水利和近海岸的海洋工程建设中，水中悬浮泥沙观测是一项长期而艰巨的任务，研究水中悬浮泥沙含量及其运动变化也显得十分重要。观测水中悬浮泥沙的传统方法有六点法，三点法及累积法等，这些方法都是人工的，它只能得到几个给定深度上泥沙浓度的离散数据；不能观测到水中悬浮泥沙含量动态变化过程。为此，光学法和声学法等观测手段的研究就格外受到重视和发展。“Ａ…     

南黄海辐射沙洲附近海域悬浮泥沙的遥感反演研究

利用2003年实测的悬浮体样品和遥感反射率数据以及美国NOAA气象卫星AVHRR数据的可见光波段,进行了南黄海辐射沙洲附近海域悬浮泥沙的遥感反演研究.结果发现:悬沙浓度和实测遥感反射率之间存在很好的线性关系(R2=0.9537, n=39),利用该关系式进行该区悬沙遥感反演取得了较好的结果.遥感反演证明,研究区悬沙浓度值由高至低从沙洲中部向沙洲周围延伸;悬沙的分布呈现出明显的季节性,秋季悬沙浓度值一般为春季的1/5;且秋季悬沙的平面扩散范围要小于春季的扩散范围.以上研究结果可为我国海岸带泥沙实时监测和悬浮泥沙遥感定量研究提供必要的基础资料.     

ASSM-Ⅱ型声学悬浮泥沙观测系统

本文介绍了一种新型的水文观测设备－“ＡＳＳＭ－Ⅱ型声学悬浮泥沙观测系统”，它可认自动，连续和长时间地实时观测水中悬浮泥沙深度分布和动态变化过程，文中介绍了工作原理框图，技术参数，性能特点及海上现场观测结果。     

铜基营养保护剂悬浮浓度快速测定方法的研究

该文选取5种铜基营养保护剂,通过采用离心干燥法、比浊法、铜氨比色法测定其悬浮浓度,并分别与直接烘干法测得的悬浮浓度建立相关方程,探讨铜基营养保护剂悬浮浓度快速测定的方法.结果表明:铜氨比色法能够快速准确地测定铜基营养保护剂的悬浮浓度,平均相对误差小于5％,同时可较大缩短分析时间(检测时间由原来的24h缩短为30 min),显示出了明显的优越性,为快速分析铜基营养保护剂提供了新方法.     

一类on-off问题的变分同化初值的误差估计

用变分同化方法,在整体观测资料下,对一类简单的"on-off"模式中的初值进行修正.研究观测误差对于变分同化方法的影响,对变分同化方法反演得到的最优初值的收敛性以及误差进行分析,从理论上分析"on-off"问题变分同化方法的有效性.     

新型翼片式斜板沉淀池的数值模拟与优化研究

本文介绍了一种新型的翼片式斜板沉淀池的工作状态,使用固液两相流方法通过Fluent模拟,并设置含沙量为变量,模拟了在含沙量80kg/m3和140kg/m3时沉淀池中泥沙浓度随时间的变化,结果表明含沙量较小时有更好的泥沙去除效率。并观测了速度模拟结果,其表明泥沙在翼片间呈环流,泥水在斜板末端呈异向流分离。     

“ASSM型声学悬浮泥沙观测系统”荣获上海市科技进步二等奖

“ＡＳＳＭ型声学悬浮泥沙观测系统”荣获上海市科技进步二等奖中国科学院东海研究站研制的“ＡＳＳＭ型声学悬浮泥沙观测系统”已在国内外多个单位推广使用。在我国有关重大工程和科技领域的工作中发挥了重要作用。交通部上海航道勘察设计研究院在１９９４年和１９９５年...     

单轴式声悬浮的实验研究及数值模拟分析

采用自行研制的单轴式声悬浮装置,实现了密度为7.9g/cm3的钢球的稳定悬浮.采用有限元方法对两种不同形状谐振腔的声场进行了数值计算和模拟,结果表明采用凹球面形反射面能有效提高悬浮性能;同时解释了实验过程中小球沿凹球面壁运动的现象,对进一步研究声悬浮装置结构对悬浮性能的影响有一定的借鉴意义.     

基于二维流体场的烟雾模拟算法

通过Navier-Stokes方程建立烟雾流体场的物理模型，以保证视觉的真实感。为了保证运算的实时性，烟雾流体场以二维网格空间∽∽为基础，在每个网格单元的中心点，采用简化的流体方程求解算法计算烟雾的速度场分布和浓度场分布，然后通过双线性插值得到整幅图像中每个像素的浓度。将烟雾模拟技术用于图像的显示特技中，以产生图像消散成烟雾的视觉效果，得到了比较满意的模拟效果。     

惯量松弛因子在格子Boltzmann方法中的应用

格子Boltzmann方法作为一种较成熟的数值模拟方法被广泛应用到了各个领域,尤其在解决多孔介质问题时有其独特的优越性,但当流动问题过于复杂时计算效率较低.因此本文将惯量松弛因子引入到格子Boltzmann方法中,对二维、三维顶盖驱动方腔流动进行了数值模拟.模拟分别从计算效率、计算精度、以及计算稳定性等方面将使用不同惯量松弛因子所得的结果与基准解进行比较,并进行讨论和分析.结果显示当惯量松弛因子取0.03到0.05之间时能使模拟结果在保持较高精度的同时提高计算效率,而且随着惯量松弛因子的增大计算效率提高得也越快,在工程材料与能源环境领域将有着重要应用.     

Prediction of bed level variations in nonuniform sediment bed channel

In the present study, a numerical model, based on one-dimensional de Saint-Venant equations along with sediment continuity equation, is developed for prediction of bed levels in non-cohesive sediments in aggrading alluvial channels. One-dimensional, unsteady flow equations and sediment continuity equations are solved using ‘shock-capturing’, second order accurate, explicit MacCormack finite difference scheme while considering upstream and downstream boundary conditions in the channel. Series of experimental investigations have been undertaken for measurements of bed and water levels in an aggrading channel due to overloading of nonuniform sediments, extracted from the bed of Tapi River at Surat City, in a flume installed in Advanced Hydraulics Laboratory of SVNIT, Surat, India. A satisfactory coupling between the water flow and sediment flow has been achieved. The sediment continuity equation is used for the each size class to compute the volume of each size class after each time step at any computational node in the computational grid. The fractional bed and suspended load transport capacities for different size fractions have been computed using fractional transport laws for nonuniform sediments. The active bed layer concept has been implemented in finite difference scheme to consider the interaction and exchange of sediment and water flow near the mixing layer. The performance of developed numerical model has been satisfactorily verified with independent experimental data of nonuniform sediment bed. Also, consideration of sediment nonuniformity in computation of bed level variation has been demonstrated by comparing the results based on sediment transport functions of uniform and nonuniform sediments.     

Effects of initial stage of dam-break flows on sediment transport

Experimental and numerical studies of dam-break flows over sediment bed under dry and wet downstream conditions are investigated and their effects on sediment transport and bed change on flow are illustrated. Dam-break waves are generated by suddenly lifting a gate inside the flume for three different upstream reservoir heads. The flow characteristics are detected by employing simple and economical measuring technique. The numerical model solves the two-dimensional Reynolds-Averaged Navier–Stokes (RANS) equations with k-ε turbulence closure using the explicit finite volume method on adaptive, non-staggered grid. The model is validated with laboratory data and is extended for simulating non-equilibrium sediment transport and bed evolution process. The volume of fluid technique is used to track the evolution of the free surface, satisfying the advection equation. The comparison study reveals that the current model is capable of defining the dam-break flow and improves the accuracy of determining morphological changes at the initial stages of the dam-break flow. A good agreement between the model solutions and the experimental data is observed.     

Development of typhoon driven wave nowcasting model in Southeast China Sea

Using Optimal Interpolation data assimilation of observed wave spectrum around Northeast coast of Taiwan Island, the typhoon driven wave nowcasting model in Southeast China Sea is setup. The SWAN model is used to calculate wave field and the input wind field is the QSCAT/NCEP data. The two-dimensional wavelet transform is applied to analyze the X-band radar image of nearshore wave field and it reveals that the observed wave spectrum has shoaling characteristics in frequency domain. The reverse calculation approach of wave spectrum in deep water is proposed and validated with experimental tests. The two-dimensional digital low-pass filter is used to obtain the initialization wave field. Wave data during Typhoon Sinlaku is used to calibrate the data assimilation parameters and test the reverse calculation approach. Data assimilation corrects significant wave height and low frequency spectra energy evidently at Beishuang station on Fujian Province coast, where the entire assimilation indexes are positive in verification moments. The nowcasting wave field shows that the present model can obtain more accurate wave predictions for coastal and ocean engineering in Southeast China Sea.     

含泥沙的流固层状介质界面波传播特性研究

在弹性波传播理论的基础上,结合边界条件,导出了流固层状介质导波特征方程,计算特征方程的频散曲线;然后结合Urick、Urick-Ament和Harker-Temple这三种悬浊液模型,计算流体层中的泥沙含量和颗粒粒径与界面波波速的关系;分析比较不同模型下泥沙含量及颗粒粒径与波速的关系图,讨论不同参数对波速的影响,得出了三种模型下波速随泥沙含量和颗粒粒径的变化趋势,最后发现Urick-Ament模型同时适用于检测悬浊液的泥沙含量和泥沙颗粒粒径,且在三种模型中有相对较好的可靠性和实用性。     

Examining top management commitment to TQM diffusion using institutional and upper echelon theories

Total Quality Management (TQM) is an enduring approach for enhancing firm competitiveness. Still, there is dearth of research regarding organisational diffusion (post-adoption) of TQM. To address this gap, this research proposes a theoretical model rooted in institutional and upper echelon theories that explain TQM diffusion via top management commitment. We surveyed 300 senior quality managers representing 300 auto-components manufacturers in India to collect data to test the proposed model using variance based structural equation modelling (PLS-SEM). The findings suggest that institutional pressures significantly influence top management commitment to TQM. Subsequently, top management commitment influences organisational diffusion of TQM via acceptance, routinisation and assimilation. Managers can use the findings of this research to better understand how to assimilate TQM so that anticipated benefits can be fully realised.     

海底沉积层中高阶界面波对多掩埋物散射分析

根据界面波散射迭代公式,并利用含多个异质体弹性动力学的散射积分方程,引出海底沉积层中界面波高阶模式对掩埋物的散射情况。根据建立的分层海底模型,对沉积层中传播的界面波进行模式分解。利用界面波传播的Green函数构建界面波散射迭代积分,并根据弹性波对多异质体散射理论,将界面波散射积分推广到对多目标的散射情况。由模式分解的结果,求解出了前三阶界面波对多目标的散射情况,并对界面波高阶模式传播及对不同目标的散射情况做了分析。     

Determination of the environmental impact of consolidation induced convective transport through capped sediment.

The presence of contaminated sediment poses a barrier to essential waterway maintenance and construction in many ports and harbors, which support 95% of US foreign trade. Cost effective solutions to remediate contaminated sediments in waterways need to be applied. Capping is the least expensive remediation alternative available for marine sediments that is unsuitable for open water disposal. Dredged material capping and in situ capping alternatives, however, are not widely used because regulatory agencies are concerned about the potential for contaminant migration through the caps.Numerous studies have been conducted on the effects of diffusion through caps, however, there is a lack of experimental data documenting the effects of consolidation induced transport of contaminants through caps. This study examines consolidation induced convective contaminant transport in capped sediment utilizing a research centrifuge. In this study, consolidation induced convective transport was modeled for 7h at 100 x g, which modeled a contaminant migration time of 8 years for a prototype that was 100 times larger than the centrifuge model. In this study, hydrodynamic dispersion was a function of the seepage velocity. And, advection and dispersion dominated the migration of contaminants. Centrifuge model results were compared to an analytical solution for advection and dispersion. The advection-dispersion equation demonstrated that the centrifuge test is a conservative estimate for predicting contaminant transport. In conducting sensitivity analysis of the advection-dispersion equation to the centrifuge modeling, as hydrodynamic dispersion decreased, the time for contaminant breakthrough increased. Moreover, as the sediment to water distribution coefficient increased, the contaminant concentration into the overlying water decreased.     

Drivers and consequences of an innovative technology assimilation in the supply chain: cloud computing and supply chain integration

Cloud Computing are innovative technologies that are being applied in the main business functions in the supply chain. This study aims to reveal the determinant factors (drivers and a relevant outcome) of the level of use or assimilation of Cloud Computing in the supply chain. In order to test three hypotheses we conducted an empirical study in 484 companies from sectors in an intermediate position in the supply chain. The data gathering method consisted of a telephone survey using a computerised system (CATI). We used structural equation modelling (SEM) to test the hypotheses. The empirical study reveals that Advanced Manufacturing Technologies pursuing the internal efficiency of the supply chain (Intra-organisational IT) and IT for capabilities in e-business/e-commerce seeking external connection of the supply chain with other companies (Inter-organisational IT) are drivers of Cloud Computing assimilation. Furthermore, supply chain integration is one of the major consequences of Cloud Computing assimilation in the supply chain.     

Data assimilation in the decision support system rodos

Model predictions for a rapid assessment and prognosis of possible radiological consequences after an accidental release of radionuclides play an important role in nuclear emergency management. Radiological observations, e.g. dose rate measurements, can be used to improve such model predictions. The process of combining model predictions and observations, usually referred to as data assimilation, is described in this article within the framework of the real time on-line decision support system (RODOS) for off-site nuclear emergency management in Europe. Data assimilation capabilities, based on Kalman filters, are under development for several modules of the RODOS system, including the atmospheric dispersion, deposition, food chain and hydrological models. The use of such a generic data assimilation methodology enables the propagation of uncertainties throughout the various modules of the system. This would in turn provide decision makers with uncertainty estimates taking into account both model and observation errors. This paper describes the methodology employed as well as results of some preliminary studies based on simulated data.     

Data assimilation through integration of stochastic resin flow simulation with visual observation during vacuum-assisted resin transfer molding: A numerical study

This study investigated data assimilation through integration of visual observation with a stochastic numerical simulation of resin flow during vacuum-assisted resin transfer molding. The data assimilation was performed using the four-dimensional asynchronous ensemble square root filter and a stochastic numerical simulation by means of the Karhunen–Loève expansion of the permeability field. Through numerical experiments of linear flow, it was verified that the estimation accuracy of the resin impregnation behavior improved compared to that when using conventional data assimilation and that the permeability field could be estimated simultaneously, although it is not explicitly related to the observation. We also investigated the applicability of the proposed method to radial-injection VaRTM by varying the model thickness. The proposed method successfully estimated the resin impregnation behavior and permeability field. Additionally, the required condition for the number of ensemble members was clarified.