Hybrid‐based snow simulation and snow rendering with shell textures

In this study, we develop a system for interactive snow simulation and rendering. Snow is modeled as a hybrid structure that handles movable snow and static snow separately. We develop a simple approach to convert between these two types of snow. Movable snow is represented by a set of particles, whereas static snow is modeled as grid cells. For a piece of movable snow (e.g., snowflake), the particles are connected using springs. Thus, we can model snow as a type of brittle material, such as a snow pile split into chunks of smaller snow pieces after a collision. To render the snow, we adopt a shell structure that has a series of concentric, semitransparent, textured shells. We applied our system to several examples, with the rendered snow appearing similar to real snow. Copyright © 2015 John Wiley & Sons, Ltd.     

Adaptive B‐spline neural network‐based vector control for a grid side converter in wind turbine‐DFIG systems

This paper presents a novel control system design for the grid‐side converter of doubly fed induction generator wind power generation systems. The control method proposed in this work is a vector control based on adaptive B‐spline neural network by using a simple fixed‐gain stabilizing control topology. The adaptive control is designed both for inner current loops and an outer DC‐link voltage loop of the grid side converter control system. To guarantee the control stability, the weights updating rule for the B‐spline neural network is synthesized by utilizing Lyapunov's direct method. To verify the effectiveness of the proposed control system, extensive simulations are performed using MATLAB/Simulink. Based on the simulation results, it is concluded that the proposed controller has improved performance compared to an optimum proportional integral control system. It is also relatively robust against external disturbances and variations of the control parameters. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Distensible air accumulators as a means of adiabatic underwater compressed air energy storage

In the near future, the electricity industry is likely to face historically significant changes. The onset of distributed generation, micro and smart grids will change the entire structured industry. An influx of intermittent renewable generators will make traditional grid balancing notably more difficult. The novel concept of underwater compressed air energy storage is a potentially promising solution that may be used to meet these challenges, especially during the current period of electrical infrastructure renewal and modernisation. Early results from a Lake Ontario Pilot Study point to the potential viability of the concept.     

Analysis of the plug-in hybrid electric vehicle for the smart grid of Canada

The conventional electricity grids, which are supposed to supply the electricity to the plug-in hybrid electric vehicles (PHEVs), need to adapt to overcome the problems of reliability, security, economics and environmental concerns. Accordingly, electric utilities in several countries are exploring the possibilities of implementing more robust interactive smart grids. This article analyses salient features of a smart grid in the Canadian perspective, and discusses PHEV and its role in the future smart grid. A simulation tool has been used to assess the impacts of charging of PHEV on the future electricity grid of Canada under different penetration rates. The article indicates the associated environmental benefits of PHEV.     

动态土工真三轴仪在砂土液化研究中的应用

为了模拟实际场地中土体变形和强度特性,研究开发了揭示侧限条件下饱和砂土震动液化机理的试验方法。文中采用了动态真三轴试验系统,该设备采用刚性板加柔性面的混合边界加载装置,并应用先进的CATS试验控制系统。试验结果表明应用动态土工真三轴仪进行砂土液化实验是可行的,并初步分析了侧限条件下的液化机理,即土体将在轴向压力、侧压和孔隙水压力相等的条件下发生液化,表明振动荷载过程中的应力重分布对砂土液化强度和孔隙水压力发展等具有显著的影响。     

多层石膏墙体钢网格式框架结构影响系数研究

GB 50011-2010《建筑抗震设计规范》并未给出多层石膏墙体钢网格式框架结构的结构影响系数,因此其抗震设计荷载取值还不明确。基于此,依据GB 50011-2010规范设计了6个典型的多层钢网格式框架结构模型,通过推覆分析得出结构的能力谱曲线,基于改进能力谱法得出罕遇地震和抗震设防烈度地震作用下的需求谱曲线。将结构的能力谱曲线和延性需求谱曲线族置于统一坐标系中,确定结构的目标位移以及性能关键点坐标。进一步考虑层数及标准层布置对结构延性和超强系数的影响,评估结构的抗震性能并给出结构影响系数取值。研究表明：多层钢网格式框架结构在抗震设防烈度地震和罕遇地震作用下的变形均满足抗震规范要求;其结构影响系数取3.0,位移放大系数取4.0;该结构可采用现行抗震规范进行设计,但设计结果偏于保守。     

污水处理厂污泥深度脱水有机调质及无机调质试验研究

污泥调质效果是决定板框压滤机出泥含水率的关键因素,为保证出泥含水率<60%,对污泥有机调质及无机调质的试验研究显得尤为重要。以天山污水处理厂为例,通过实验室试验和上机试验确定污泥浓缩段有机调质适用的PAM型号,将污泥含水率浓缩至97%以下,固体回收率高。同时通过板框压滤机脱水试验,随着浓缩污泥含水率的变化,污泥无机调质所需FeCl3和Ca(OH)2的投加量亦有明显变化。     

火灾下预应力网架结构的力学性能

本文建立了考虑火灾升温和升降温作用下预应力网架结构力学性能的有限元模型,并对预应力网架的变形模式、预应力索拉应力随受火时间的变化规律进行了研究.结果表明,预应力网架经历升降温火灾后,残余变形较大,索中拉应力增加,因此对其进行火灾安全设计时应考虑降温阶段结构破坏的可能性.     

中国空间网格结构三十年的发展

简要回顾了中国空间结构三十年来的发展历程,侧重对近十年来我国空间结构特别是空间网格结构(网架、网壳以及一些新型网格结构如张弦梁(单向、双向)、弦支穹顶及索穹顶等结构)的发展及应用予以总结,并对空间网格发展中存在的问题和今后的发展方向进行了阐述。     

某大跨度单层空间曲面钢网壳的安装技术

结合某工程大跨度单层空间曲面钢网壳结构屋面,介绍大跨度单层空间曲面钢网壳结构屋面安装技术,提出带支撑柱网壳结构高空散拼安装施工工艺,并阐述其安装定位、安装工艺、落架施工等关键技术。通过施工实践表明,该安装技术取得了良好的效益,保证了施工质量和安全,缩短了工期。