量化设计方法在天然气特大储罐结构安全中的应用

为提高特大储罐结构的本质安全性，以地震环境为例，研究了量化设计方法在特大储罐结构本质安全中的应用。从设置储罐尺寸、选择保冷材料并计算漏热量和计算外罐体临界失稳压力值三方面，进行了特大储罐结构本质安全的量化设计。以用钢量最少为实验指标，采用ansys软件建立了量化设计方法、API设计方法和GB设计方法的特大储罐有限元模型，比较了工作工况和试水工况下的应力强度。结果表明，采用量化设计方法，较其他两种方法节省钢材用量在50 t以上，得到的应力强度与设定值更接近，量化效果好；在地震载荷施加作用下，其结构的环向应变和径向位移均在安全范围内，危害程度低，满足本质安全性要求。     

中国化工产品国际竞争力研究(Ⅰ)--模型的建立

根据结构分析原理,建立了宏观和微观系统的竞争力模型,确定了各模型的评价指标体系,对一些指标进行了简化处理,给出了定性指标的量化处理方法,应用扣分法解决了大系统的评分难题,应用层次分析的方法建立了模型的判别矩阵,讨论了相对重要度的计算方法.     

水泥生产CO_2排放量化方法分析及数学模型建立

分析了国内外水泥工业CO2排放量化方法,针对不同来源CO2的排放,对比了各种量化方法的优劣,在此基础上提出了建立水泥生产CO2排放数学模型拟采用的量化方法;然后通过解构水泥生产工艺流程,划分了水泥生产CO2排放量的计算边界,按照提出的量化方法逐一对每个计算边界的CO2排放量进行计算,建立水泥生产CO2排放数学模型。     

非电解质溶液扩散系数的理论研究评述

许多过程都涉及扩散控制的传质,相应的扩散速率计算对过程工程的精确量化具有重要意义.本文简述了扩散速率的理论表述模型,并着重介绍了非电解质溶液内扩散系数的理论分析计算途径.分子动力学模拟正处于发展中,并用于估算自扩散系数,但进入实用化阶段尚需时日,唯象模型仍为最重要的理论计算手段.作为最常用的方法,由无限稀释浓度下的扩散系数以及合适的插值方法可计算特定浓度下的扩散系数;自由体积理论是半经验性模型,可以计算自扩散系数,并借助混合规则计算相互扩散系数;最后,对扩散系数的理论研究作了展望.     

BTA及其羧基烷基酯衍生物缓蚀性能的量子化学研究

引言 缓蚀剂的缓蚀效率与其结构有着密切的关系。采用量子化学（QC）计算方法可以得到表征缓蚀剂分子结构的参数，使得从微观层次上探讨其缓蚀作用机理成为可能，并进而为新型缓蚀剂的设计与合成提供有力的理论指导。上世纪七十年代，Vosta和Eliasek首先尝试用量子化学方法研究缓蚀剂性能与量化参数的相关性，随后腐蚀科学工作者进行了大量、深入的研究工作。量化计算已经成为研究缓蚀剂作用机理的有效方法。     

蒸压砂加气混凝土墙板碳排放计算方法

为了实现对蒸压砂加气混凝土墙板全寿命周期中碳排放量的计算,并对其绿色环保性能进行量化分析,通过墙板碳排放量计算参数选择,建立墙板碳排放计算模型,计算墙板全寿命周期碳排放量与节能减排量。结合实例,针对蒸压砂加气混凝土墙板和颗粒板两种不同墙板在实际应用中的碳排放量进行计算,计算结果表明：蒸压砂加气混凝土墙板的碳排放量更低,该结果可实现对蒸压砂加气混凝土墙板绿色环保性能的量化,综合其碳排放量可进一步对其经济效益和社会效益进行量化分析。     

涂层性能状态评价数学模型

分析了影响涂层性能和耐久性的各种主要因素,采用层次分析法建立涂层状态的评价模型,通过比较因素之间的相对影响强度构建判断矩阵,从而计算各种因素对系统的影响权重。提出涂层状态指数概念并给出计算方法及步骤。通过涂层状态的等级划分,为涂层性能状态和耐久性最终实现量化评价提供了方法。     

多目标决策综合评价数量化方法的应用

本文针对云浮硫铁矿外部运输方案的复议实例,采用系统工程决策技术进行系统分析、量化方法——层次分析法和化多为少法,从建立层次结构模型、构造判断矩阵及其排序计算。判断矩阵一致性检验及综合评价等方面,阐明该方法应用的基本过程。     

用产品加工价值评价乙烯原料经济性

以典型乙烯企业为例,通过PIMS模型,计算各种裂解产品的加工价值并比较了不同原料情况下增值效益,为乙烯原料优化提供量化依据。     

N-苄基苯丙醇胺的合成及量化计算研究

以苯丙醇胺和苯甲醛为原料合成席夫碱，经硼氢化钠还原得N-苄基苯丙醇胺；使用Hyperchem7．0程序，用半经验方法对标题化合物进行了量化计算研究。     

Kinetics of hydration of tricalcium aluminate in the presence of gypsum

Based on a conceptual model for the stages of hydration of tricalcium aluminate in the presence of gypsum, a mathematical model was developed for the kinetics of hydration. The model was solved, illustrated and compared to experimental heat release data. Analytical equations were presented for the first two stages, while the last stages of hydration reduced to a previously developed model for the hydration of tricalcium aluminate in the absence of gypsum. Results suggested that pore diffusion through a thickening ettringite barrier layer controlled the first stage of hydration, while pore diffusion through a thinning ettringite barrier layer controlled the second stage. After the ettringite layer disappeared, the reaction of the remaining tricalcium aluminate proceeded more rapidly, but by a similar mechanism, than in the absence of sulfate containing species.     

Multi-phase hydration model for prediction of hydration-heat release of blended cements

Recently, the heat release during cement hydration and the so-caused temperature rise was exploited for (i) identification of material properties of early-age cement-based materials (stiffness, strength), and (ii) determination of the diameter and the cement content of jet-grouted structures. In this paper, the underlying hydration model for determination of the heat release and its rate is refined for Ordinary Portland Cements (OPC) and extended towards blended cements. Hereby, the overall degree of hydration with one kinetic law is replaced by a multi-phase hydration model, taking the hydration kinetics of the main clinker phases into account. As regards blended cements, which are commonly used in engineering practice, the effect of slag hydration is incorporated into the presented multi-phase model. The developed hydration model for both plain and blended cement is validated by means of differential-calorimetry (DC) experiments.     

硅酸盐水泥水化热的研究及其进展

硅酸盐水泥水化硬化过程中会释放大量的水化热,由此而产生的温度应力是导致混凝土出现裂缝的一个主要原因,对大体积混凝土的影响更为显著。因此,水泥混凝土水化热的研究长期以来受到国内外水泥和混凝土科学家及建筑工程界的重视。本文在总结前人关于水泥水化热研究方面提出的一些理论计算公式的基础上,综合分析了影响水泥水化热的因素,介绍了国内外关于水泥水化放热模型的最新研究进展以及水泥生产中降低水化热的技术措施。     

Multiphasic finite element modeling of concrete hydration

This paper presents a model predicting the development of hydration and its consequences on temperature and water content. As it considers the effects of climatic conditions, the proposed model is a promising tool to evaluate the temperature, hydric and hydration fields of structures in situ.The hydration model predicts the hydration evolution of several main species (not only clinker but also mineral additions like fly ash or silica fume for instance). For each component, the modeling considers hydration development and chemical interaction between reactions. It also takes into account temperature and water content effects on reaction kinetics through thermal and hydric activation. Hydration development in turn modifies the thermal and hydric states of material. The result is a numerical model coupling hydration, and the thermal and hydric states of cement-based material.The model was tested on a 27 m³ concrete block in situ equipped with temperature sensors situated in the core and close to the face exposed to solar radiation.     

Kinetic modeling of calcium aluminate cement hydration

The hydration of iron-rich calcium aluminate cement (CAC) has been investigated by differential calorimeter and quantitative powder X-ray diffraction (QXRD). A simplified stoichiometric model of early age CAC hydration based on reaction schemes of the principal mineral monocalcium aluminate was employed. The CAC characteristic feature of retardation of nucleation and growth mechanism with temperature requires employing more than one kinetic mechanism to describe the resulting complex hydration kinetics. This paper proposes a single equation kinetic model of CAC hydration which comprises simultaneously three main mechanisms: nucleation and growth, chemical interaction and mass transfer. A gradual change between kinetic mechanisms was grasped with a reasonable inter-dependency of the kinetic parameters. The overall hydration kinetics was described relative to the amount of the both reactants, cement and free water.     

Mathematical modeling of tricalcium silicate hydration

Based on conceptual models for the stages in the hydration of tricalcium silicate, a mathematical model was developed. The separate resistances in the mathematical model correspond to the phenomenological stages of the conceptual model. Comparison of model output with available hydration data gave a reasonable fit between the model and the data.     

-3 ℃养护下考虑矿物掺合料影响的水泥水化程度计算模型

针对多年冻土地区工程施工时混凝土养护的问题,采用10%、20%、30%的矿粉和粉煤灰替代量等量替代水泥,测试了-3 ℃恒温养护条件下0.38水胶比水泥浆体在各个龄期的水泥水化热,计算了水泥水化程度;分析了龄期及矿物掺合料对水泥水化程度的影响规律,建立了综合考虑龄期和矿物掺合料替代量的水泥水化程度计算模型.结果表明:-3 ℃恒温养护下,矿物掺合料等量替代水泥,水泥浆体的水化程度会降低,粉煤灰降低水化程度的值要比矿粉高;在相同矿物掺合料替代量下,随着龄期的增长,矿物掺合料对水泥水化程度的影响逐渐减弱;同一龄期时,随着矿物掺合料的增加,矿物掺合料对水泥水化程度的影响逐渐增强;利用建立的模型计算了分别掺入15%矿粉和粉煤灰的水泥水化程度,与实测值相比,计算值偏离值较少,预测精度较高.     

Hydration kinetics modeling of Portland cement considering the effects of curing temperature and applied pressure

A hydration kinetics model for Portland cement is formulated based on thermodynamics of multiphase porous media. The mechanism of cement hydration is discussed based on literature review. The model is then developed considering the effects of chemical composition and fineness of cement, water-cement ratio, curing temperature and applied pressure. The ultimate degree of hydration of Portland cement is also analyzed and a corresponding formula is established. The model is calibrated against the experimental data for eight different Portland cements. Simple relations between the model parameters and cement composition are obtained and used to predict hydration kinetics. The model is used to reproduce experimental results on hydration kinetics, adiabatic temperature rise, and chemical shrinkage of different cement pastes. The comparisons between the model reproductions and the different experimental results demonstrate the applicability of the proposed model, especially for cement hydration at elevated temperature and high pressure.     

Modeling of hydration reactions using neural networks to predict the average properties of cement paste

This paper presents a hydration model that describes the evolution of cement paste microstructure as a function of the changing composition of the hydration products. The hydration model extends an earlier version by considering the reduction in the hydration rate that occurs due to the reduction of free water and the reduction of the interfacial area of contact between the free water and the hydration products. The BP Neural Network method is used to determine the coefficients of the model. Using the proposed model, this paper predicts the following properties of hardening cement paste: the degree of hydration, the rate of heat evolution, the relative humidity and the total porosity. The agreement between simulation and experimental results proves that the new model is quite effective and potentially useful as a component within larger-scale models designed to predict the performance of concrete structures.     

Kinetics of hydration of tricalcium aluminate

Based on a generally accepted conceptual model for the hydration of tricalcium aluminate, a mathematical model was developed for the kinetics of hydration. The model was solved, illustrated, and compared to experimental heat release data. Results suggested that pore diffusion through a hexagonal phase barrier layer, dissolution of this layer and crystallization of the cubic phase from solution were all contributing resistances in the model, although pore diffusion through the barrier layer was the rate-controlling step.