Optimal design of groundwater remediation systems using a multi-objective fast harmony search algorithm

A new multi-objective optimization methodology is developed, whereby a multi-objective fast harmony search (MOFHS) is coupled with a groundwater flow and transport model to search for optimal design of groundwater remediation systems under general hydrogeological conditions. The MOFHS incorporates the niche technique into the previously improved fast harmony search and is enhanced by adding the Pareto solution set filter and an elite individual preservation strategy to guarantee uniformity and integrity of the Pareto front of multi-objective optimization problems. Also, the operation library of individual fitness is introduced to improve calculation speed. Moreover, the MOFHS is coupled with the commonly used flow and transport codes MODFLOW and MT3DMS, to search for optimal design of pump-and-treat systems, aiming at minimization of the remediation cost and minimization of the mass remaining in aquifers. Compared with three existing multi-objective optimization methods, including the improved niched Pareto genetic algorithm (INPGA), the non-dominated sorting genetic algorithm II (NSGAII), and the multi-objective harmony search (MOHS), the proposed methodology then demonstrated its applicability and efficiency through a two-dimensional hypothetical test problem and a three-dimensional field problem in Indiana (USA).     

预应力锚索抗滑桩支挡结构体系数值模拟研究

为克服现行预应力锚索抗滑桩设计计算方法存在诸多问题,探讨了快速拉格朗日有限差分程序（FLAC）,对预应力锚索抗滑桩支挡结构体系进行整体数值模拟方法。以较好的考虑抗滑桩、预应力锚索、滑坡体及锚固地层之间的相互作用、共同工作特性,提高设计计算效率。工程实例数值模拟计算结果比较表明,该方法是可行的。不失为一种有效的新途径。可供有关设计部门参考。同时,数值模拟也揭示,与普通抗滑桩相比,预应力锚索抗滑桩受力更合理,可使桩的截面尺寸、桩的锚固深度及桩间距等的设计更加经济。     

Investigations of subsurface flow constructed wetlands and associated geomaterial resources in the Akumal and Reforma regions,Quintana Roo,Mexico

Subsurface flow constructed wetlands in the village of Akumal, Quintana Roo, Mexico were surveyed to determine the general status of the wetland systems and provide baseline information for long term monitoring and further study. Twenty subsurface flow wetlands were surveyed and common problems observed in the systems were overloading, poor plant cover, odor, and no secondary containment. Bulk mineral composition of aggregate from two subsurface flow constructed wetlands was determined to consist solely of calcite using bulk powder X-ray diffraction. Some soil structure is developed in the aggregate and aggregate levels in wetlands drop at an estimated rate between 3 and 10 cm/year for overloaded wetlands owing to dissolution. Mineral composition from fresh aggregate samples commonly is a mixture of calcite and aragonite. Trace amounts of Pb, Zn, Co, and Cr were observed in fresh aggregate. Coefficients of permeability (k) varied from 0.006 to 0.027 cm/s with an average values being 0.016 cm/s. Grain size analysis of fresh aggregate samples indicates there are unimodal and multimodal size distributions in the samples with modes in the coarse and fine sand being common. Investigations of other geologic media from the Reforma region indicate that a dolomite with minor amounts of Fe-oxide and palygorskite is abundant and may be a better aggregate source that the current materials used. A Ca-montmorillonite bed was identified in the Reforma region as well and this unit is suitable to serve as a clay liner to prevent leaks for new and existing wetland systems. These newly discovered geologic resources should aid in the improvement of subsurface flow constructed wetlands in the region. Although problems do exist in these wetlands with respect to design, these systems represent a successful implementation of constructed wetlands at a community level in developing regions.     

Navigating the future of tsunami risk communication: using dimensionality,interactivity and situatedness to interface with society

Two-dimensional paper maps are well-established tsunami risk communication tools in coastal communities. Advances in GIS, geovisualization and spatial interface technologies suggest new opportunities to deliver tsunami risk communication using 3D, interactive and situated risk visualization. This paper introduces a set of geovisual interface constructs—dimensionality–interactivity–situatedness (DIS)—and evaluates their presence, absence and distribution in 129 examples of existing academic and public visual tsunami risk communication. The resulting analyses reveal structural differences in the distributions of DIS found in each of academic and public risk communication literatures, and opportunities for interactive location-aware risk communication. The second half of this paper reports on three new tsunami risk visualization interfaces informed by and developed to demonstrate how we might explore new undeveloped risk communication territory revealed by the DIS cube analysis. We discuss the design, rationale and implications of: EvacMap; ARRO3D; and Tsunamulator. These risk visualization interfaces deliver location-aware, user-centred risk maps, as well as virtual risk maps and tsunami simulations that can be viewed while standing in situ in coastal environments. This work is a first step intended to help the risk communication community systematically engage an emerging territory of interactive and location-aware 3D visualizations. This work aims to facilitate and encourage progress towards developing a new strand of interactive, situated geovisual risk communication research, by establishing these guiding constructs, their relationship to existing works and how they may inform the design of future systems and usability research.     

新型锚固与注浆技术研究与应用

提出了一种新型的土层锚固与注浆技术,即全孔不排土和钻进,灌浆连续完成的新工艺,该方法施工速度快,支护效果好,采用了深基护坡土层锚杆拉固工程设计的神经网络新方法,提高了设计的科学化和智能化水平,从理论方面进行分析和论证。     

An adaptive high-dimensional model representation method for reliability analysis of geotechnical engineering problems

In this study, a new reliability analysis method was developed based on the adaptive high-dimensional model representation (HDMR) and applied to geotechnical engineering problems. For practical problems requiring finite element (FE) analysis or other numerical methods to evaluate system responses such as stresses and deformations, an efficient and accurate metamodeling technique is needed because it is not efficient or straightforward to directly adopt the conventional sampling-based or gradient-based reliability analysis approaches. In this work, an adaptive metamodeling approach was created and studied based on the HDMR framework and augmented radial basis functions (ARBFs). In this adaptive ARBF-HDMR technique, a simple and inexpensive first-order ARBF-HDMR metamodel was first constructed to explicitly express a performance function, and an alternate first-order reliability method (FORM) was applied to locate the design point and compute the reliability index. A local window was then defined such that additional sample points were generated and a higher-order HDMR component function was created using ARBF and added to the existing ARBF-HDMR metamodel. The accuracy of the ARBF-HDMR metamodel was improved through this adaptive process, especially in the region surrounding the design point. One mathematical and four geotechnical engineering problems were studied and solved using the proposed adaptive ARBF-HDMR approach. The proposed method was found to be capable of obtaining accurate reliability indices within a few iterations in all test problems.     

剩余推力法及其在斜坡稳定性评价中的应用

在总结已有研究成果的基础上,针对现有的剩余推力法计算公式中没有详细说明应如何考虑降雨的影响,以至在这一问题上目前还存在着很多模糊概念的状况,将降雨对斜坡稳定性的影响进行了系统分类,并尝试着给出了各影响因素的定量确定方法,然后在剩余推力法公式和程序中,加入了这些量化关系。将改进的剩余推力法应用于实例计算表明,计算结果符合实际情况。     

Numerical analysis of foundation columns to support widening of embankments

Increased traffic volume has made it necessary to increase highway capacities by widening embankments and pavements. Adding a new embankment to an existing embankment induces additional stresses and deformations beneath the widened and existing portions of the embankment. Differential settlement may develop between and within the new and existing portions of the embankment, especially over soft soils. This differential settlement often causes pavement distress, such as longitudinal cracks or the drop-off (or sinking) of pavement sections. Different techniques have been adopted to remedy these problems, including the use of foundation columns, such as deep mixed columns, vibro-concrete columns, stone columns, and aggregate piers. However, design procedures for foundation columns constructed for this purpose are not well developed. The analyses of eight cases of column-supported widened embankments and two untreated foundations are presented in this paper. The factors considered include the consolidation of foundation soils under existing embankments and the spacing, region, and modulus of foundation columns. Two-dimensional finite difference software was used after the calibration of the model against a field case study and numerical analyses were conducted to investigate stresses and deformations of the widened embankments over soft soil with or without the remediation of foundation columns. The results presented in this paper include the vertical and the horizontal displacements, the maximum settlements, the transverse gradient change, and the distribution of the additional stresses induced by the widening. Recommendations are made for the design of foundation columns to remedy roadway pavement failure due to widening of embankments.     

基于GIS的地质项目管理系统平台研究

在深入总结分析已有多个地质项目管理系统研发与应用的基础上,本研究充分应用网络技术、地理信息技术和数据库技术,借鉴以往的成功经验,结合当今地质项目管理实际需求而开展。本次研究的主要成果是建立基于GIS的地质项目管理系统综合平台,通过模板来管理各类地质项目信息,既可以同时管理多个历史项目库,也可以随时利用已有模板新增项目库。在地质项目资料的保存、管理及应用开发中,该平台已经取得较好的应用效果。     

High‐order ADE scheme for solving the fluid diffusion equation in non‐uniform grids and its application in coupled hydro‐mechanical simulation

To improve the stability and efficiency of explicit technique, one proposed method is to use an unconditionally stable alternating direction explicit (ADE) scheme. However, the standard ADE scheme is only moderately accurate and restricted to uniform grids. This paper derives a novel high‐order ADE scheme capable of solving the fluid diffusion equation in non‐uniform grids. The new scheme is derived by performing a fourth‐order finite difference approximation to the spatial derivatives of the diffusion equation in non‐uniform grid. The implicit Crank‐Nicolson technique is then applied to the resulting approximation, and the subsequent equation is split into two alternating direction sweeps, giving rise to a new high‐order ADE scheme. Because the new scheme can be potentially applied in coupled hydro‐mechanical (H‐M) simulation, the pore pressure solutions from the new scheme are then sequentially coupled with an existing geomechanical simulator in the computer program Fast Lagrangian Analysis of Continua. This coupling procedure is called the sequentially explicit coupling technique based on the fourth‐order ADE scheme (SEA‐4). Verifications of well‐known consolidation problems showed that the new ADE scheme and SEA‐4 can reduce computer runtime by 46% to 75% to that of Fast Lagrangian Analysis of Continua's basic scheme. At the same time, the techniques still maintained average percentage error of 1.6% to 3.5% for pore pressure and 0.2% to 1.5% for displacement solutions and were still accurate under typical grid non‐uniformities. This result suggests that the new high‐order ADE scheme can provide an efficient explicit technique for solving the flow equation of a coupled H‐M problem, which will be beneficial for large‐scale and long‐term H‐M problems in geoengineering.     

喀斯特洞穴灯光照明系统研究述评与展望

灯光照明是开展洞穴旅游的必备条件,是喀斯特洞穴旅游开发与可持续发展的重要内容。文章通过对万方数据、CNKI、Springer Link、Elsevier SDOL、EBSCO、Google Scholar、Google、超星学术发现系统等8个国内外数据库和搜索工具进行检索,结合纸质文献,最后获得有关洞穴灯光照明系统的研究文献56篇（部）。研究内容主要涉及洞穴灯光照明的起源与发展、洞穴照明光源的类型及选择、洞穴照明灯具的选择与安装、洞穴灯光照明系统的设计、洞穴灯光的操控系统、洞穴灯光照明系统的安全控制、洞穴灯光照明等7个方面。学术界对该领域的研究历史较长、研究方法多样,但研究成果数量有限,研究的视角较为微观,研究成果的普适性较弱。在未来的研究中应重点关注以下问题：研究的系统性、多学科的融合性、研究的针对性、洞穴灯光照明系统技术标准的制订、新材料与新技术在洞穴照明中的应用、洞穴灯光照明系统的经济性、洞穴照明光源的比较研究等。     

Offshore pile system model biases and reliability

ABSTRACT

Recent hurricanes between 2004 and 2008 in the Gulf of Mexico provide valuable new information about design model biases and uncertainties because multiple offshore platforms were loaded beyond the predicted capacity of their pile systems and because there was a failure of a pile system. A Bayesian calibration of model bias factors based on predicted versus observed performance of pile systems in hurricanes indicates that the conventional American Petroleum Institute design method for pile capacity is slightly conservative by about 10% for base shear (i.e. lateral) failures of pile systems in clay, unbiased for overturning (i.e. axial) failures of pile systems in clay, and conservative by more than 50% for overturning failures of piles systems in sand. The epistemic uncertainty in the updated bias factors is represented by coefficient of variation values of about 0.25 for base shear and overturning failures of pile systems in clay and 0.35 for overturning failures of pile systems in sand. A reliability assessment with the calibrated model bias factors shows that the current design practice produces lower reliability for a pile system with three piles versus one with eight piles and lower reliability for a pile system failing in overturning versus one failing in base shear. Therefore, the current design practice could potentially be improved by taking into account the mode of failure and the redundancy in the pile system to provide for a more uniform level of reliability.     

Performance evaluation of disaster monitoring systems

Understanding the performance of disaster monitoring systems is a key to understanding their success; therefore, various qualitative and quantitative measures and metrics can be applied in the characterization and analysis of such systems. Through evaluation studies, problems that impede a disaster monitoring system performance can be identified. The results can be used for system design, control, and capacity planning. Previous studies address technical performance analysis metrics for analyzing monitoring systems leaving out human and organizational dimensions of such systems. Thus, the primary objective of this study is to identify and describe a set of metrics that may be employed to evaluate such systems. This study may be valuable to researchers and practitioners involved in disaster and emergency response studies in planning the transportation of vital first-aid supplies and emergency personnel to disaster-affected areas and in improving chances of survival after a disaster.     

CTP技术在印刷行业应用前景探讨

CTP技术是当今印刷界最热门的话题,针对目前CTP应用的现状,详细的阐述计算机直接制版技术存在的优缺点,探析CTP技术应用中存在的主要问题以及注意事项。     

金刚石钻头热压烧结微机自动控制系统的研究

针对目前金刚石钻头热压烧结过程中存在的稳定性差、可靠性低等问题，研制了金刚石钻头热压烧结微机自动控制系统，成功地解决了以上问题。该系统包括硬件设计改造和软件编程两大部分，硬件改造部分主要是改进中频炉和红外测温仪的接口，使之可以顺利与计算机进行数据交换；软件部分主要是设计过程的控制软件，使得计算机可以按照预先设定好的程序进行工作，避免了人工操作可能带来的手工误差。     

蜀河水电站防渗帷幕灌浆技术

采用灌浆技术处理大坝渗漏是一个较为复杂的问题,针对灌浆技术在蜀河水电站中的应用,介绍了防渗帷幕灌浆的设计思路和施工方法,总结了防渗帷幕灌浆施工规律和存在的问题,对灌浆技术的应用提出了一些看法和建议。     

Designing submission and workflow services for preserving interdisciplinary scientific data

Developments in information and communication technologies offer new opportunities to use and integrate scientific data that have been collected by researchers and scholars from diverse fields of inquiry. Data archives and digital repository systems are being developed to preserve current and legacy scientific data and technical information for use by others. However, capabilities are needed for data producers of various disciplines to easily and efficiently submit their data into archival systems for preservation. Analysis of digital preservation requirements has identified the requirements for services to support the submission and review of scientific data for preservation. Data submission and review processes are segmented into services, which are defined to support efficient preparation of scientific data for ingest into an archive or digital repository system. A model is proposed to inform the design of submission and workflow services for preserving interdisciplinary scientific data. Recommendations are offered for improving the design and evaluation of systems and services to prepare and preserve scientific data for new uses by interdisciplinary communities of users in the future. Improving the infrastructure that enables members of the scientific community to submit their data for archiving contributes to the scientific data stewardship and data curation capabilities needed to preserve scientific data for future generations of users.     

非开挖施工地下管线的改进措施

非开挖施工地下管线有很多工艺方法,这些工艺中存在某些需要改进的地方。并且在适当条件下可以采用新的方法代替现有的方法。第一是非开挖施工“超重地下管道”时,拉管工序中的局部连接新方法的设想。第二是在特殊情况下施工地下电力管线时PE管管节连接方式的选择。第三是在合适的地层中采用“拔管法”更换废旧地下管线的施工工艺。     

神经网络模型在坝基扬压力影响因子量化分析中的应用

本文应用改进的BP网络模型定量分析坝基扬压力的影响因子,赋于网络不同的权值来表示网络的输入变量(水位、温度、时效等因子)对网络的输出变量(扬压力)的影响程度,从而确定各影响因子分量对扬压力的影响比例。采用Levenberg Marquardt算法训练网络,网络达到一定的次数后收敛。实例计算结果表明,该模型具有计算精度高、简便实用等特点。因而认为,把神经网络模型应用于探讨诸如环境量对于效应量影响程度的一类问题,具有好的前景。