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1.
A. Benhamida I. Djeran-Maigre H. Dumontet S. Smaoui 《International Journal of Rock Mechanics and Mining Sciences》2005,42(7-8):996-1005
The modelling of hydromechanical behavior of clayey sediments by homogenization theory is described. The rheological model of clays buried in depth requires a three-dimensional approach and laboratory experiments to quantify the model parameters. An iterative process which can be coupled to any homogenization method is used to model the porous media behavior. Hydromechanical compaction results from oedometric experiments are simulated with the proposed model. 相似文献
2.
《Drying Technology》2007,25(1):75-84
This article proposes a multiscale computational model able to calculate energy consumption in a batch lumber kiln. A dual-scale computational model of wood drying deals with the boards/stack interaction and serves as a basis for the present work. A new module was added here that calculates heat losses through kiln walls (convection, condensation) and the energy used by each kiln component (fans, heating elements, humidifier, vacuum pump, etc.). The corresponding mathematical formulation is presented and then theoretical results are compared to those collected in an industrial vacuum kiln. As application example, the effect of air reversal, air velocity, and kiln insulation are exhibited, which depicts the great potential and prospects of this new tool for energy savings in relation to the product quality. 相似文献
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局部均值函数的求取是局部均值分解(LMD)的关键环节。针对局部均值函数求取存在偏差进而造成模态混叠的问题,提出了一种基于局部积分均值的LMD风电机组齿轮箱故障诊断方法。该方法改变了对相邻两极值点求平均值的思路,采用求取相邻两极值点的局部积分均值,再通过滑动平均法进行平滑处理,最终得到局部均值函数。为实现风电机组齿轮箱故障诊断,首先采用改进LMD方法对信号进行降噪处理,然后采用多尺度熵提取降噪处理后信号的特征向量,最后采用极限学习机进行故障诊断。通过仿真分析,证明了该方法能有效解决模态混叠现象,提高了LMD的分解精度。试验验证分析表明,该方法的故障诊断准确率为100%,通过对比分析表明,该方法优于其他故障诊断方法,具有工程应用价值。 相似文献
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In this work, the polymer melt filling process is simulated by using a coupled finite volume and level-set based immersed boundary (LS-IB) method. Firstly, based on a shape level set (LS) function to represent the mold boundary, a LS-IB method is developed to model the complex mold walls. Then the non-isothermal melt filling process is simulated based on non-Newtonian viscoelastic equations with differ-ent Reynolds numbers in a circular cavity with a solid core, and the effects of Reynolds number on the flow patterns of polymer melt are presented and compared with each other. And then for a true polymer melt with a small Reynolds number that varies with melt viscosity, the moving interface, the temperature distributions and the molecular deformation are shown and analyzed in detail. At last, as a commonly used application case, a socket cavity with seven inserts is investigated. The corresponding physical quantities, such as the melt velocity, molecular deformation, normal stresses, first normal stress differ-ence, temperature distributions and frozen layer are analyzed and discussed. The results could provide some predictions and guidance for the polymer processing industry. 相似文献
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This paper describes the design and application of the Atmospheric Evaluation and Research Integrated model for Spain (AERIS). Currently, AERIS can provide concentration profiles of NO2, O3, SO2, NH3, PM, as a response to emission variations of relevant sectors in Spain. Results are calculated using transfer matrices based on an air quality modelling system (AQMS) composed by the WRF (meteorology), SMOKE (emissions) and CMAQ (atmospheric-chemical processes) models. The AERIS outputs were statistically tested against the conventional AQMS and observations, revealing a good agreement in both cases. At the moment, integrated assessment in AERIS focuses only on the link between emissions and concentrations. The quantification of deposition, impacts (health, ecosystems) and costs will be introduced in the future. In conclusion, the main asset of AERIS is its accuracy in predicting air quality outcomes for different scenarios through a simple yet robust modelling framework, avoiding complex programming and long computing times. 相似文献
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针对低照度条件下彩色图像的细节丢失与视觉效果不佳等问题,提出一种改进的低照度彩色图像增强算法。对三个颜色分量图像分别进行同态高低通滤波处理,在提取高频成分的同时,保留部分低频成分。对其中高频图像进行多尺度Retinex算法、指数变换及量化等处理,加强图像细节;对低频图像进行量化和线性伸缩变换处理,避免图像过度增强。MATLAB仿真结果表明,该算法不仅改善了低照度图像的视觉效果,而且在信息熵、峰值信噪比和对比度等性能指标上也有较大提升。 相似文献
10.
针对声呐图像的特点,提出了一种新的基于马尔可夫随机场(MRF)的非监督声呐图像自动分割方法。研究发现,声呐图像混响区基本上都服从高斯分布,然而,其直方图离散化的分布效果不利于图像的自动分割,因此,通过一种快速有效的高斯金字塔模型对声呐图像进行预处理,使得处理后的声呐图像的海底混响区直方图服从高斯分布。在此基础上提出了一个能够自动确定声呐图像分类个数的模型,并通过该模型结合一种局部能量极值化的方法对马尔科夫模型的初始化参数进行估计,从而形成一种完全自动的声呐图像分割模型。最后,利用该模型对声呐图像数据进行了分割实验,并和其他典型的分割算法进行了比较,验证了该方法的有效性及快速性。 相似文献