An analytical solution for geotextile-wrapped soil based on insights from DEM analysis

This paper presents a novel analytical solution for geotextile-wrapped soil based on a comprehensive numerical analysis conducted using the discrete element method (DEM). By examining the soil–geotextile interface friction, principal stress distribution, and stress–strain relations of the constituent soil and geotextile in the DEM analysis, a complete picture of the mechanical characterization of geotextile-wrapped soil under uniaxial compression is first provided. With these new insights, key assumptions are verified and developed for the proposed analytical solution. In the DEM analysis, a near-failure state line that predicts stress ratios relative to the maximums at failure with respect to deviatoric strain is uniquely identified; dilation rates are found to be related to stress ratios via a single linear correlation regardless of the tensile stiffness of the geotextile. From these new findings, the assumptions on the stress-state evolution and the stress–dilatancy relation are developed accordingly, and the wrapped granular soil can therefore be modeled as a Mohr–Coulomb elastoplastic solid with evolving stress ratio and dilation rate. The development of the proposed analytical model also demonstrates an innovative approach to take advantage of multiscale insights for the analytical modeling of complex geomaterials. The analytical model is validated with the DEM simulation results of geotextile-wrapped soil under uniaxial compression, considering a wide range of geotextile tensile stiffnesses. To further examine the predictive capacity of the analytical model, the stress–strain response under triaxial compression conditions is solved analytically, taking both different confining pressures and geotextile tensile stiffnesses into account. Good agreement is obtained between the analytical and DEM solutions, which suggests that the key assumptions developed in the uniaxial compression conditions also remain valid for triaxial compression conditions.     

Analysis of Post Irradiation Experiments in PWR Using New Nuclear Data Libraries

For the precise calculation of the burnup of minor actinide isotopes, a code system-SWAT has been developed. This system analyzes burnup problems with neutron spectrum that depends on the type of a reactor and the irradiation history, using latest evaluated nuclear data files JENDL-3 or ENDF/B-Vl. The post irradiation test in TRINO and the recent experiment in typical PWRs in Japan were analyzed with SWAT. These analyses show that the results of U and Pu for high burnup fuels almost agree with experimental results but those for middle burnup fuels do not agree with them. The results for Am and Cm isotopes still have large discrepancy. The average C/E of ²⁴³Am is –0.79, and that of ²⁴⁴Cm is –0.70 for high burnup (–33,000 MWd/tU) samples.

For middle burnup (–25,000 MWd/tU) samples, the C/E for ²⁴⁴Cm is over 2.0. The discrepancy is partially explained by considering the power peaking history of first cycle and second cycle.     

核电工程建设进度控制的关键路径分析

以M310堆型为基础．结合大亚湾、岭澳工程的建设经验．研究核电工程建设进度控制的关键路径分析表明．核电工程建设的关键路径是核岛土建、核岛安装、与一回路冷态调试相关的单系统调试及联合调试。对于核岛土建．关键路径在反应堆厂房主体土建施工、预应力张拉、重点区域的土建房间移交和关键土建／安装接口移交;对于核岛安装．有4条关键路径：对于调试．分为冷态调试相关的16个单系统调试和联合调试两个阶段。     

Effect of residual stresses to the crack path in alumina/zirconia laminates

Laminates with alternating layers are well known from nature. The strongly bonded alumina/zirconia (Al₂O₃/ZrO₂) layers can combine high fracture resistance with high strength and stiffness when properly tailored. The presence of compressive residual stresses formed in Al₂O₃ layers can suppress and deflect cracks propagating through the layers. The crack path is governed by both the elastic properties and the internal stress field of individual layers. The laminates with various layer-thickness ratios ranging from 0.1 to 3 were used to investigate the effect of residual stresses and influence of crack formation pattern on the crack path development. The indentation surface cracks observed in various alumina-zirconia laminates exhibit the same crack deflection independently on the level of internal stresses. The crack deflection observed on the fracture surfaces of bending specimens was related to the indentations cracks. The complicated crack path was explained experimentally by 3D reconstruction with the support of numerical simulations.     

Mining fleet management systems: a review of models and algorithms

The objective of this paper is to review and document the mine fleet management systems’ models and algorithms. The purpose is to understand the algorithms behind the fleet management systems and the proposed academic solutions in this area to identify any gaps in the current literature and to open up opportunities to establish research questions that need to be addressed in an integrated simulation and optimisation operational planning research framework. In this paper, we review industrial fleet management systems and the main academic algorithms behind such systems. The fleet management systems are divided into three subsequently related problems to review: shortest path, production optimisation and real-time dispatching. Finally, the limitations of current algorithms for fleet management systems are documented in terms of mining practice feasibility and optimality of the solution on large-scale problems. The results of this literature review enable us to evaluate the logical links between major components of an integrated simulation and optimisation operational planning framework with current theory of fleet management systems.     

Probabilistic performance prediction model for Austrian torrent control infrastructure

Due to the growing stock of torrent control structures and decreasing investments, the protection level can be reduced in the long term. Therefore, the focus of the future investments has been shifted on efficiency improvement and maintenance of existing structures. The maintenance of the existing structures is necessary to ensure safety from natural hazards, which are increasing as a consequence of the climate change. Due to the increasing number of structures, there is a strong need to develop a good maintenance management for these infrastructure works. This study is based on data from the condition rating programme of the Austrian Service for Torrent and Avalanche Control. For the structures relevant in this work, 75,343 records were available. The data were examined for different construction type and construction materials. The reliability of the structures was determined by means of the Markov chain. The study describes a homogeneous Markov chain model formed by the data of the condition rating. The result of this study is a proposal for a time to failure (TTF) and a time to repair (TTR) for several construction types with different construction materials as well as the time-dependent use of construction materials in the sector of the Austrian torrent control infrastructure.     

Specific emitter identification for satellite communication using probabilistic neural networks

Electromagnetic signal emitted by satellite communication (satcom) transmitters are used to identify specific individual uplink satcom terminals sharing the common transponder in real environment, which is known as specific emitter identification (SEI) that allows for early indications and warning (I&W) of the targets carrying satcom furnishment and furthermore the real time electromagnetic situation awareness in military operations. In this paper, the authors are the first to propose the identification of specific transmitters of satcom by using probabilistic neural networks (PNN) to reach the goal of target recognition. We have been devoted to the examination by exploring the feasibility of utilizing the Hilbert transform to signal preprocessing, applying the discrete wavelet transform to feature extraction, and employing the PNN to perform the classification of stationary signals. There are a total of 1000 sampling time series with binary phase shift keying (BPSK) modulation originated by five types of satcom transmitters in the test. The established PNNs classifier implements the data testing and finally yields satisfactory accuracy at 8 dB(±1 dB) carrier to noise ratio, which indicates the feasibility of our method, and even the keen insight of its application in military.     

西湖凹陷中央背斜带中北部花港组储层成岩相测井识别

基于测井资料对未取心井区域的成岩相进行人工智能识别成为必然的趋势。利用岩心铸体薄片与扫描电镜资料,划分西湖凹陷中央背斜带中北部花港组储层成岩相,总结了六种典型成岩相类型,各类成岩相所对应的测井响应差异明显。结果表明,测井系列自然伽马、补偿中子、声波时差、深侧向电阻率、浅侧向电阻率和密度等为成岩相判别敏感曲线。对比岩心薄片资料表明,概率神经网络模型可以准确识别未取心井段的成岩相,识别准确率可达到90%以上。     

我国科技期刊的现状与市场化发展策略

伴随着我国综合国力和科研能力的提升,我国已成为科技期刊大国,但是其发展不能适应我国科技论文强国地位的要求,为此,必须走一条市场化经营之路。在现有科技期刊体制下,理顺各种关系,成为独立的市场化主体、构建独立的国家级科技期刊评价标准,建立利益共同体实现规模经营,增强品牌意识,提升品牌效应,完善市场化经营能力和方式,是科技期刊市场化经营的路径选择。     

高浓盘磨的安装

为提高公司产品质量的关键物理指标,青山纸业2011年从安德里兹公司引进一套高浓打浆系统安装在。2纸机生产线上。该系统从2011年9月交付设备安装至同年12月试机、投入运行。本文介绍该系统的核心设备——高浓盘磨的安装。