Finite element analysis and modeling of water absorption by date pits during a soaking process

Date pits for feed preparation or oil extraction are soaked in water to soften before milling or extrusion. Knowledge of water absorption by the date pits helps in better managing the soaking duration. In this research, the process of water absorption by date pits was modeled and analyzed using Fick's second law of diffusion, finite element approach, and Peleg model. The moisture content of the pits reached to its saturation level of 41.5% (wet basis) after 10 d. The estimated coefficient of diffusion was 9.89×10-12 m2/s. The finite element model with a proposed ellipsoid geometry for a single date pit and the analytical model fitted better to the experimental data with R2 of 0.98. The former model slightly overestimated the moisture content of the pits during the initial stages of the soaking and the latter model generally underestimated this variable through the entire stages of soaking process.     

林火扑救指挥系统空间数据库构建

在通过对林火扑救需求分析的基础上,对空间数据库进行合理的设计,将空间数据和专题数据有机地组织和管理起来,应用UML方法设计得出空间数据库对象模型图,基于Geodatabase数据模型,使用CASE工具生成林火扑救指挥系统数据库,有效地提高了数据库的可用性,为林火扑救系统的应用奠定基础。     

结构方程模型在英语阅读语料库中的研究

该文从建立基础型英语阅读语料库(English Reading Corpus,ERC),然后采用结构方程模型(Structural EquationModeling,SEM)及语言统计学方法,从英语阅读语料库的语篇复杂度、学习者个体的信息获取水平及情感因素三方面进行了建模及相关关系的探索性研究,在数据统计和分析的基础上,找到了满足置信度及可拟合的数学模型,以期能对英语阅读教学和学习有所启示。在通过对SEM的ERC建模之后的数据进行全面、准确的统计分析,能够为提高英语阅读教学质量提供有价值的统计数据和分析资料。     

建设工程设计阶段造价控制新方式——基于BIM的建设工程造价管理

从信息技术在工程建设领域中的应用这个角度来分析,在设计阶段传统造价控制方式存在一定的问题,从技术角度进一步分析了产生这些问题的原因,提出了在设计阶段从技术上有效地控制造价的新方式——基于BIM的造价管理模式,并进一步探讨了这种模式的具体实现方案.     

某高职院校教材管理系统的UML建模与设计

统一建模语言UML是面向对象分析和设计过程中重要的图形可视化建模工具,文章以某高职院校教材管理系统的开发为背景,简单介绍了在高职院校信息化建设过程中的UML分析和建模过程.     

Bifurcations and catastrophes of a two-degrees-of-freedom nonlinear model simulating the buckling and postbuckling of rectangular plates

The nonlinear buckling and postbuckling behavior of rectangular plates in symmetric and antisymmetric modes is re-examined, in the context of Bifurcation and Catastrophe Theories, using a two-degrees-of-freedom model, which has been adopted for the same purpose in the pioneer literature. At first the perfect system is dealt with in detail, symbolically utilizing the exact as well as the approximate equilibrium equations, the latter being products of a universal unfolding of the original total potential energy function. Conditions for the existence of remote secondary bifurcations are fully assessed and the stability of critical states is determined, revealing sudden qualitative changes in the postbuckling response of the perfect system, which have been also reported for the actual continuous structural system—the rectangular plate—using the von Kárman equations. Thereafter, the imperfection sensitivity is dealt with, introducing symmetric as well as asymmetric imperfections, considered as individual or consecutive perturbations of the perfect system. It is found that symmetry breaking bifurcations give birth to complicated cusp singularities, which may lead to unexpected jumps from one to two-mode remote postbuckling behavior. Finally, considering the general case of random imperfections, higher order two-mode singularities are revealed, mainly of the double-cusp catastrophe type, which have been also discovered in the postbuckling response of rectangular plates, a fact validating the choice of the foregoing nonlinear simulation.     

矿产储量估算系统的开发研究

通过对矿产储量估算过程及软件开发新技术的调研,对传统储量估算（断面法、块段法等）和地统计学储量估算及可视化做了详细研究,实现了基于COM的集三维建模、储量估算为一体的可视化储量估算系统,该系统已经对某矿区数据进行了储量试算,结果与勘探报告一致。     

基于DEM的醴陵市土地利用空间格局分析

地形是土地利用空间格局形成的基础,本文利用遥感影像、土地利用现状图、地形图、地貌图,以及野外实际调查资料,通过建立DEM、地貌分区、高程分级、叠加分析等过程,以地貌分区和高程分级区域为基本空间单元,分析了湖南醴陵市土地利用空间格局及与地形因子的关系。结果表明土地利用类型空间分布具有强烈的区域差异性,各地貌分区与高程分级区域的土地利用组合不同,同一土地利用类型在不同地貌分区和高程区域的分布存在差异;土地利用类型空间分布与海拔高程具有显著的相关性,随海拔高程增加,林地分布比例增大,耕地、园地、城乡居民用地、工矿用地、水域和未利用土地均呈减少趋势。在此基础上,构建了研究区土地利用空间格局的三维景观模型,直观地再现了土地利用空间格局与所处环境的关系,有利于辨识不同地貌部位土地利用的分布规律与差异,可为研究区农业结构调整和土地资源可持续利用提供参考。     

国内图书馆界个性化服务研究现状与趋势

本文通过对近几年的文献分析后梳理出目前国内图书馆个性化服务研究的趋势和热点问题，从而得出资源研究和用户研究两大研究视角，并分析了技术研究在这一主题的发展情况。参考文献20。     

基于并行工程的模具CAD／CAM技术

本介绍了并行工程的概念和方法,讨论了并行工程的特点,探讨了基于并行工程的模具CAD/CAM技术,提出了特征建模,信息集成,适用于并行工程的CAPP,加工过程仿真是其关键所在。