复合膜生物反应器有机物去除动力学的研究

本研究对向膜生物反应器中投加陶粒填料的复合式膜生物反应器（HMBR）处理生活污水的工艺条件进行了系统试验。在优化的工艺条件下进行了HMBR去除有机物的反应动力学研究，确定了该反应器生物处理反应动力学参数，并建立了反应器中有机底质降解动力学模型。     

浸没式厌氧膜生物反应器有机物降解动力学模型研究

针对浸没式厌氧膜生物反应器(SAnMBR)的工艺特点,以反应器内物料衡算为基础,通过动力学推导得到了SAnMBR降解有机物的动力学模型.试验中采用新型浸没式厌氧双轴旋转膜生物反应器(SDRAnMBR)处理啤酒废水,得到了相关动力学参数Vmax=2.36 d-1;Ks=847.92mg·L-1,K=0.0028 L·d-1·mg-1.并对模型进行了验证,试验结果与模型计算结果基本一致.     

人工肝生物反应器中溶解氧浓度动态分布的模型与数值分析

研究了人工肝生物反应器的结构特点,并在对反应器内部液体流动与气液传质规律进行分析的基础上,结合反应器的实际需要,建立了基于一维轴向扩散模型的人工肝专用生物反应器溶解氧浓度动态分布的数学机理模型. 利用有限差分方法对模型离散化求解,得到了流动速度、氧传质系数及细胞耗氧速率对反应器内部溶解氧浓度分布的影响规律. 通过对模型数值解的分析得到了特定条件下反应器内的优化参数为液体流速0.55 mm/s,传质系数0.31 s-1,扩散系数0.02 mm2/s. 最后,通过仿真数据与实测实验的对比验证了该模型的正确性,其平均误差在±5%以内. 本模型的建立在理论上验证了该专用生物反应器可以提供稳定且均匀的溶解氧浓度分布,同时也为下一代新型反应器的优化设计提供了参考数据和理论依据.     

5种生物滞留池填料的吸附性能分析

通过静态摇床试验研究了沸石、火山岩、煤渣、蛭石和珍珠岩对NH+4-N、TP、TN和COD等的吸附效果,进行了等温吸附曲线拟合和吸附动力学研究,并利用模拟降雨试验考察了实际的去污效果.试验结果表明,蛭石和沸石的总体吸附能力较强,其余填料的吸附能力相对较差.5种填料的等温吸附过程符合Langmuir模型.动力学研究表明,准二级动力学模型更符合5种填料的吸附速度特点.以上述5种材料作为填料分别进行模拟降雨试验,试验结果表明,沸石填充的生物滞留池对NH+4-N的去除率达到80％;煤渣和蛭石对TP去除率较高,在60％～70％;蛭石和火山岩系统对TN的去除率较高,达到80％～90％;蛭石对COD的去除效果最好,去除率在65％左右.     

传统法建立动力学模型的不确定性和沿程法(RAPRA)建模

本文通过数值分析、参数灵敏性分析和实验研究,考察了动力学模型及参数、反应器操作方式和操作条件等因素对模拟结果的影响,认为传统研究方法建立动力学模型具有不确定性.根据反应器设计、模拟要求,提出了动力学建模方法——沿程法,该法在模拟反应器行为时可靠性优于传统法.     

SMBR中消化反应的动力学研究

在一体式膜生物反应器处理稀土氨氮废水的实验中,为进一步了解一体式膜生物反应器中氨氮降解规律及微生物生长的动力学模型,通过合理的理论推导和实验验证,得出消化过程中的基质降解的动力学模型,测出了基质降解动力学模型中的相关参数,并推导出了微生物生长的动力学模型。结果表明:氨氮降解符合Monod方程,并从生物膜组成角度,清楚地揭示其生长动力学行为的变化。     

喷雾反应器中甲烷水合物生长动力学模型

提出了喷雾反应器中甲烷水合物的形成机理,并引入传质对水合反应影响的有效因子等参数,得到了喷雾法生成水合物的改进动力学方程.通过实验验证,实验数据与模型计算数据基本吻合,平均误差为4.63%.方程回归得出甲烷水合物表观活化能(Ea)为54.25 kJ/mol,根据文献结果,说明喷雾反应器中甲烷水合物生长过程由表面反应所控制.     

影响复合式生物反应器运行的主要因素

为考察溶解氧、温度和有机负荷对复合式生物反应器的净化效能。实验室试验对稳定期处理系统的净化效能进行了研究。试验结果表明：温度对投加耐冷菌群的复合式生物反应器净化效能的影响不大，溶解氧在2mg／L～4mg／L之间，OLR控制在0．1～0．3kgCOD／（kg膜泥量·d）时，反应器有着较高的净化效能。     

膜相扩散控制型药物释放体系动力学的研究

本文将化学工程学原理应用于药物控制释放这一交叉学科,针对膜相扩散释放进行了动力学研究,建立、推导了“非稳态、有扩散边界层影响的释放动力学模型’,解决了现有模型“准稳态”假设产生的偏差,使模型更接近于实际释放过程.根据医疗科学和药物控制释放技术的发展趋势,设计了新颖的聚乙烯-乙烯醇/维生素B_(12)混合药膜释放体系.利用该体系验证了本文所建立的模型.     

间歇式搅拌罐酶反应器的热动力学模型

建立了间歇式搅拌罐酶反应器（ＢＳＴＥＲ）的动力学模型和热动力学模型，并用精氨酸酶催化水解Ｌ—精氨酸的反应验证了模型的可行性，同时研究了可逆抑制剂对这些模型的影响。     

Modeling and control of the melt index in HDPE process

We investigate the model for an industrial isothermal HDPE slurry reactor. The model, consisting of several nonlinear equations, can be linearized to give sets of linear time invariant state space model. The effectiveness of the linearized model is verified by the numerical simulations. A simple model predictive control scheme is constructed based on the linear state space model. The value of the melt index is obtained from the values of the manipulated and controlled variables generated from the control scheme. The control performance can be evaluated from the comparison between the computed melt index values and measured melt index values. The control scheme shows good tracking performance in the numerical simulations. We believe that the model developed in the present study can be effectively used to predict process variables as well as to control the melt index.     

Repeated measures with zeros

Consider repeated measures data with many zeros. For the case with one grouping factor and one repeated measure, we examine several models, assuming that the nonzero data are roughly lognormal. One of the simplest approaches is to model the zeros as left-censored observations from the lognormal distribution. A random effect is assumed for subjects. The censored model makes a strong assumption about the relationship between the zeros and the nonzero values. To check on this, you can instead assume that some of the zeros are 'true' zeros and model them as Bernoulli. Then the other values are modeled with a censored lognormal. A logistic model is used for the Bernoulli p, the probability of a true nonzero. The fit of the pure left-censored lognormal can be assessed by testing the hypothesis that p is 1, as described by Moulton and Halsey. The model can also be simplified by omitting the censoring, leaving a logistic model for the zeros and a lognormal model for the nonzero values. This is approximately equivalent to modeling the zero and nonzero values separately, a two-part model. In contrast to the censored model, this model assumes only a slight relationship (a covariance component) between the occurrence of zeros and the size of the nonzero values. The models are compared in terms of an example with data from children's private speech.     

EXPERIMENTAL DETERMINATION OF PARAMETERS FOR A PARTIAL SEGREGATION MODEL

A proposed two-parameter model for partial segregation is analyzed with respect to the determination of the parameters of the model. An iterative scheme for the calculations is readily done for a particular system. An elementary, bimolecular second order reaction was performed in a premixed perfectly mixed continuous stirred lank reactor. The necessary data are obtained for seven values of the initial concentration of reactants, the parameters of the model calculated from one of the runs, and the other experiments (other values of C_B0/C_A0) used to check the accuracy of the model. The iterative scheme is found fast and accurate, although an alternative method is discussed. The model appears adequate and the values of the parameters are within permissible ranges.     

Methods for designing characterisation targets for digital cameras

Characterisation targets usually include a set of physical coloured samples. A characterisation model can be derived between the colorimetric values (tristimulus values) and camera responses (RGB values) taken from an imaging device such as a digital camera capturing the colours in the target. The performance of such a model is highly dependent upon the number of colours and the colour region in the characterisation target. An ideal characterisation target should provide accurate model prediction without requiring too many samples. In this paper, a computational method is presented for colour selections to train a camera characterisation model based on a fourth‐order polynomial model including 35 terms. Compared with other available methods, the newly developed method performed better. It is proposed that this method be applied to generate generic targets in terms of colorimetric values. These targets should work reasonably well for a wide range of materials.     

Theoretical and experimental analyses of thermal properties of porous polycrystalline mullite

This paper examined experimentally and theoretically the thermal diffusibility (α), heat capacity (C_P1) at a constant pressure (1 atm, 101.33 kPa) and thermal conductivity (κ=C_P1α) for the porous mullite ceramics with 0–55% porosity in a wide temperature range from 298 to 1073 K. The change in the κ values with temperature or porosity for the porous mullite was similar to the temperature dependence or porosity dependence of the α values, which were greatly reduced by the air included in the pores. The κ values for the porous mullite were theoretically analyzed with two model structures of pore–dispersed mullite continuous phase system (A model) and mullite–dispersed pore continuous phase system (B model). The measured κ values at 0–23% porosity agreed well with the κ values calculated for model A structure. In the high porosity range from 33% to 55%, the measured κ values deviated from the κ curve calculated for model A structure and approached the κ value curve for model B structure with increasing porosity. The real microstructure of 30–60% porosity is equivalent to the mixed microstructure of model A and model B for the thermal conductivity measurement.     

Reactive oxygen species may cause amyloid beta aggregation by free radical polymerization

Alzheimer's disease (AD), the most common form of dementia, is closely related to the overproduction of reactive oxygen species (ROS). A kinetic model based on free radical polymerization of amyloid beta (Aβ) utilizing ROS as an initiator is proposed. Kinetic parameters involved in the model are tuned with the reported experimental data on fibril molecular weight. The tuned model is used to simulate time evolution of fibril length and polydispersity of Aβ aggregates. The simulated values are compared with the reported experimental values for these fibril properties. A good agreement is observed between the model simulated fibril properties and the reported experimental data. This supports the hypothesis of ROS as the cause of Aβ aggregation using the free radical polymerization. The proposed model is also able to predict the sigmoidal growth of fibrils at different set of parameter values. Sensitivity analysis has been performed to check the reliability of the proposed model. It is envisaged that the proposed model will be helpful to elucidate ROS-based therapeutic strategies for AD treatment in near future.     

C3O1铜基催化剂甲醇合成反应动力学——(Ⅲ)平行反应的效率因子

对于铜基催化剂上甲醇合成反应,选取C0和CO_2的加氢反应作为关键反应,CO和CO_2作为关键组分,本文提出了求算C301铜基催化剂对于这两个平行反应效率因子的关键组分扩散模型,求得效率因子ζco、ζco_2的数值解.在内循环无梯度反应器中测定了5MPa压力下,Φ5×5mm柱状C301催化剂只计入内扩散影响的宏观反应速率,获得ξco、ξco_2的实验测定值.ξco、ξco_2的模型计算值与实验值比较的结果表明该模型是计算平行反应效率因子的简便而可行的方法.     

Modeling of antioxidant loss from polyolefins in hot-water applications. I: Model and application to medium density polyethylene pipes

This paper is the first in a series of related papers describing the application of a diffusion/reaction model to the loss of antioxidants from polyolefins in hot-water applications. The model, which is derived in detail, describes the time evolution of antioxidant concentration profiles in the exposed material in terms of adjustable parameters. The parameters describe the rates of diffusion, evaporation, extraction, and chemical reaction of antioxidant. Parameter values are determined by least-squares fitting of the calculated concentration profiles to experimental profiles. The model is applied to a commercial medium density polyethylene pipe material, where antioxidant concentration data from thermal analysis is available for water/air (internal/external) exposure at three temperatures. A comparison of parameter values with literature data is undertaken. The temperature dependence of the parameters is considered and activation energies are compared with literature values. The relative importances of the loss mechanisms are discussed. The effect of boundary conditions on parameter values is considered by application of the model to a limited amount of available data for air/air and water/water exposures. The results indicate that for water/air exposure, extraction by the water phase is the dominating loss mechanism.     

石油馏份加氢精制的混合动力学模型

本文首先对加氢精制类二级反应动力学模型的研究做了简要的回顾,然后提出了一个混合反应动力学模型,可用以处理一级反应动力学模型及作者提出的类二级反应模型所不能处理的实验数据得到了较为满意的结果。编制了一个可同时用一级反应,类二级反应模型或本模型对数据进行处理并做出判断的电子计算机程序。     

Simulation of compression molding for sheet molding compound considering the anisotropic effect

An improved model of the anisotropic flow characteristics of SMC (sheet molding compound) during compression molding is developed. This study is intended to complement our previous paper, which was conducted to determine the anisotropic parameters for short fiber reinforced thermosets SMC (16). Our prior study measured flow viscosities and material anisotropy by means of axisymmetric and plane strain compression molding tests. The current study, in order to identify the superior flow model from the choices (1) isotropic, (2) constant anisotropic and (3) varying anisotropic, applies the finite element method to obtain numerical results, which are subsequently compared with experimental results to determine the flow model with the best fit. The anisotropic parameters of the shear directions are determined by use of normal and planar parameters because SMC is planar isotropic. Six varying anisotropic parameters and six viscosity values are estimated during molding experiments, which are conducted at room temperature so that the polymer does not cure. Two-dimensional molding numerical analyses are carried out to explain two experimental classes, axisymmetric and plane strain compression molding. The load-levels predicted by the isotropic model, anisotropic model (parameter values fixed) and anisotropic model (parameter values varying) are compared with the experimentally derived values, the results showing that the varying anisotropic model best fits SMC compression behavior.