井壁附近瞬态温度的数值计算方法

在石油钻井开采等过程中研究热量在地层中的传播具有很重要的意义。特别是在进行井漏机理研究中,利用它可以分析温度对井眼破裂压力、裂缝重启压力以及裂缝延伸压力的影响。本文使用有限差分法近似地求得近井壁地层的温度分布。利用此方法,可以求得任意时刻井壁温度随井深的分布,任意时刻、任意井深处井壁温度的径向分布,任意点温度随时间的变化,从而进一步了解温度在石油工程上的影响。     

热含量不变量的SAR图像点特征变化检测

针对区域变化检测受分类器精度影响大、无法探测出内部细微变化这一问题,本文提出了基于热含量不变量的合成孔径雷达（Synthetic aperture radar,SAR）图像点特征变化检测.该方法利用热核特征,具有计算简便、矩阵扰动性小的特点,且有效地降低了噪声的干扰.由热核不变量的统计特性,采用期望极大化（Expectation maximization,EM）算法解决了SAR图像的自动变化检测.同时通过对权的讨论,给出了适用于SAR图像的权函数定义.对单波段单极化SAR与多极化SAR图像,本文算法相比于基于像素和似然比的方法,能够更快速更精确地检测到变化区域.     

鲁奇甲醇生产装置数学模拟和工况分析——(Ⅰ)鲁奇副产蒸汽管壳型甲醇合成塔

以一氧化碳加氢和二氧化碳加氢为独立反应、甲醇和二氧化碳为关键组分,建立了鲁奇副产蒸汽管壳型甲醇合成塔催化床的一维拟均相数学模型,并求得管内各组分气体浓度和温度分布。讨论了不同操作条件对出口甲醇浓度和产量的影响。由于管外副产4.0MPa 的蒸汽,床层温度平稳。     

MMA－ST乳液共聚合成核阶段的数学模型

研究了ＭＭＡ－ＳＴ乳液共聚合动力学规律，提出了成核阶段数学模型，进行了计算机模拟，并对模型预计结果与实验数据进行了比较和讨论     

聚合物熔体在圆锥口型的挤出胀大方程

在聚合物熔体入口收敛流变中引入纯拉伸流变概念，应用张量理论进行了定量分析，导出了一个描述圆锥口型的挤出胀大方程。研究表明，入口收敛拉伸流变，是取合物熔体产生了强烈的弹性形变，导致了较大的挤出物胀大比。     

Experimental and theoretical study of membrane-aerated biofilm reactor behavior under different modes of oxygen supply for the treatment of synthetic wastewater

This study compares, experimentally and theoretically, five different modes of supplying oxygen to a membrane-aerated biofilm reactor (MABR), and search for the more efficient ways of treating wastewaters. A single-tube MABR was used to measure the decrease of an organic substrate (sodium acetate) in water by supplying oxygen in different modes, namely: (1) by feeding the membrane tube either with oxygen or air (or none of them); (2) in some cases by simultaneous sparging air to the residual water. The dynamics of the substrate and oxygen consumption were measured during the batch experiment, and two mathematical models are developed to predict their transient responses using a Monod kinetic with dual substrate limitation. The models predict biomass growth and the production of extracellular polymer substances (EPS), which in turn causes the biofilm to grow; they account for the counter-diffusion of substrate and oxygen within the EPS structure that contains the cells, and one of them incorporates the mass transport by convection and diffusion in the surrounding liquid contained inside the interconnected pores and channels within the biofilm. Transport and kinetic parameters are estimated from experiments, and both models successfully predict concentration measurements in some of the set of experiments. It was found that all of the modes of oxygen supplied in a MABR were more efficient than the traditional suspended cell process.     

牛顿迭代法在求解物料平衡式中的应用

高炉数学模型是分析炉况、指导操作的有效工具.物料平衡是高炉生产遵循的基本理论,建立高炉数学模型中常需要建立物料平衡式计算相关数据.文章提出采用Newton迭代法来求解物料平衡式,并针对炉身模拟模型建立了物料平衡式并进行了求解.结果表明,Newton迭代法能够有效的求解物料平衡方程式,并具有易于软件实现,以及高效率、高精度的优点.     

Mathematical modeling of reverse osmosis systems

The present investigation pertains to modeling of seawater desalination system. A simulation model was developed and verified for a small-scale reverse osmosis system. The proposed model combines material balances on the feed tank, membrane module andproduct tank with membrane mass transfer models. Finally a comprehensive simulation model has been developed incorporating the effect of mass transfer inhibition The model is non-linear differential equation representing the feed concentration as a function of operating time and space. The solution of the simultaneous differential equations was obtained using the fourth order Runge-Kutta method, due to self starting and stability. The model was verified using the experimental data from the literature [17,24]. Parameter sensitivity was carried out to select the proper step size. The simulation was run for over 1000 11 enabling a prediction of operational performance at high overall system recoveries.     

Probabilistic pseudo-morphology for grayscale and color images

Mathematical morphology offers popular image processing tools, successfully used for binary and grayscale images. Recently, its extension to color images has become of interest and several approaches were proposed. Due to various issues arising from the vectorial nature of the data, none of them imposed as a generally valid solution. We propose a probabilistic pseudo-morphological approach, by estimating two pseudo-extrema based on Chebyshev inequality. The framework embeds a parameter which allows controlling the linear versus non-linear behavior of the probabilistic pseudo-morphological operators. We compare our approach for grayscale images with the classical morphology and we emphasize the impact of this parameter on the results. Then, we extend the approach to color images, using principal component analysis. As validation criteria, we use the estimation of the color fractal dimension, color textured image segmentation and color texture classification. Furthermore, we compare our proposed method against two widely used approaches, one morphological and one pseudo-morphological.