Molecular Dynamics, Physical Properties, Diffusion Coefficients and Activation Energy of the Lithium Oxide (Li-O) and Sodium Oxide (Na-O) Electrolyte (Cathode)

This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied a gap-free model using molecular dynamics. Physical quantities such as volume and pressure of the Na-O and Li-O systems exhibit similar behaviors around the thermodynamic ensembles NPT and NVE. However, for the Na2O system, at a minimum temperature value, we observe a range of total energy values;in contrast, for the Li2O system, a minimum energy corresponds to a range of temperatures. Finally, for physicochemical properties, we studied the diffusion coefficient and activation energy of lithium and potassium oxides around their melting temperatures. The order of magnitude of the diffusion coefficients is given by the relation Dli-O >DNa-O for the multiplicity 8*8*8, while for the activation energy, the order is well reversed EaNa-O > EaLi-O.

Determination of Natural Logarithm of Diffusion Coefficient and Activation Energy of Thin Layer Drying Process of Ginger Rhizome Slices

This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhizome. Drying of ginger was modeled, and then the effective diffusion coefficient and activation energy were determined. For this purpose, the experiments were done at six levels of varied temperatures: 10°C, 20°C, 30°C, 40°C, 50°C and 60°C. The values of effective diffusion coefficients obtained in this work for the variously treated ginger rhizomes closely agreed with the average effective diffusion coefficients of other notable authors who determined the drying kinetics and convective heat transfer coefficients of ginger slices.

Calculation of Activity Coefficient from Immiscible Binary Alloy Phase Diagram by Means of Modified Sub-regular Solution Model

The modified sub regular solution model was used for a calculation of the activity coefficient of immiscible binary alloy systems. The parameters needed for the calculation are the interaction parameters, λ 1 and λ 2, which are represented as a linear function of temperature, T . The molar excess Gibbs free energy, G m E, can be written in the form G m E= x A x B[( λ 11 + λ 12 T )+( λ 21 + λ 22 T ) x B ] The calculation is carried out numerically for three immiscible binary alloy systems, Al Pb, Cu Tl and In V. The agreement between the calculated and experimentally determined values of activity coefficient is excellent.

Activity coefficient calculation model for NaAl(OH)_4-NaOH-H_2O system

Resorting to Debye-Hückel equation, the conception of the apparent dielectric constant ε′ of sodium aluminate solution is introduced. By supposing that all the influences are attributed to it, ε′ is successfully related to caustic ratio αK, concentration mNaOH, T and temperature T. Then an activity coefficient calculation model for NaAl（OH）4-NaOH-H2O system from 25℃ to 100℃ is established, which can be used in much wider αK and mNaOH, T ranges than those covered by the equilibrium solubility data.

Prediction of Henry's constant in polymer solutions using PCOR equation of state coupled with an activity coefficient model

In this paper,the polymer chain of rotator(PCOR) equation of state(EOS) was used together with an EOS/G^E mixing rule(MHV1) and the Wilson's equation as an excess-Gibbs-energy model in the proposed approach to extend the capability and improve the accuracy of the PCOR EOS for predicting the Henry's constant of solutions containing polymers.The results of the proposed method compared with two equation of state(van der Waals and GC-Flory) and three activity coefficient models(UNIFAC,UNIFAC-FV and Entropic-FV) indicated that the PCOR EOS/Wilson's equation provided more accurate results.The interaction parameters of Wilson's equation were fitted with Henry's constant experimental data and the property parameters of PCOR,a and b,were fitted with experimental volume data(Tait equation).As a result,the present work provided a simple and useful model for prediction of Henry's constant for polymer solutions.

Activity Coefficient Models to Describe Vapor-Liquid Equilibrium in Ternary Hydro-Alcoholic Solutions

In this study,three semipredictive activity coefficient models:Wilson,non-random-two liquid model(NRTL),and universal quasi-chemical model(UNIQUAC),have been used for modeling vapor-liquid equilibrium properties of ternary mixtures that include substances found in alcoholic distillation processes of wine and musts.In particular,vapor-liquid equilibrium in ternary mixtures containing water + ethanol + congener has been modeled using parameters obtained from binary and ternary mixture data.The congeners are substances that although present in very low concentrations,of the order of part per million,are important enological parameters.The results given by these different models have been compared with literature data and conclusions about the accuracy of the models studied are drawn,recommending the best models for correlating and predicting phase equilibrium properties of this type of mixtures.

Experimental Investigation and Modeling of Activity Coefficient at Infinite Dilution of Solutes Using Dicationic Solvent Based on Pyrrolidinium as a New Stationary Phase in Gas Chromatography

Activity coefficients at infinite dilution, γ ∞ i, were calculated for 12 solutes, with organic solutes including linear alcohols (methanol, ethanol, propanol), linear alkanes (heptane, octane), benzene, toluene, cyclohexane, 1, 2-dichloroethane, trichloroethylene, acetonitrile and carbon tetrachloride. The values of γ ∞ i were determined via either thermodynamic or artificial neural network modelling at different temperatures. A comparison between extracted results from these two methods confirmed that experimental and predicted results are roughly the same. The accuracy of predicted results proves this model is fully compatible with a wide range of solutes, and it can readily be used as an alternative to conventional gas-liquid chromatography for the measurements of activity coefficient at infinite dilution.

Comparison of Some Methods on Prediction of Activity Interaction Coefficient

Based on Miedema's semiempirical formation enthalpy model for binary alloys, free volume theory and ageneral solution model, a new model for prediction of activity interaction coefficient ε is proposed. The calculatedresults are better in agreement with the experimental values than the two previous models. The related theories andmodels are discussed according to the degree of agreement with experimental values.

基于随机系数Logit模型的专利价值评估研究——以主动降噪技术为例

[研究目的]从分析专利价值入手,通过经济学研究方法围绕专利侵权损害赔偿的标准进行定量研究,为评估专利价值提供有意义的知识增量。[研究方法]基于实证产业组织理论,采用随机系数Logit模型,以无线蓝牙耳机主动降噪(ANC)技术作为研究对象,构建该技术遭受侵权的反事实情形来估计经济指标变化,由此评估专利价值及侵权赔偿比例。[研究结论]专利侵权企业的行为产生了反竞争效应,提升了企业垄断势力,挤占了其他耳机企业的生存空间,也对潜在进入企业形成了进入威胁。蓝牙耳机价格中约有4.06%源于ANC专利标识。如果发生ANC专利侵权,赔偿额度应是侵权企业利润的2.6~2.8倍。该方法利用市场数据在均衡框架下评估专利价值,为相关研究提供了新方向。

含杂质CO_(2)混合体系的气液相平衡计算模型

对含杂质CO_(2)体系相平衡的准确表征是CCUS(碳捕集、利用与封存)应用中的关键。为探讨针对此类体系相平衡计算的最佳热力学模型,基于CO_(2)/N_(2)、CO_(2)/O_(2)与CO_(2)/H_(2)O等3种二元混合工质的气液相平衡数据,分别使用状态方程(PR、SRK、BWRS、CPA、GERG-2008)和活度系数模型(NRTL、UNIQUAC)进行了气液闪蒸计算。结果表明,针对含杂质CO_(2)二元混合体系,CPA方程具有最高的计算精度,其结果与实验值的平均偏差仅为4.75%。随后,采用CPA方程对CO_(2)/N_(2)、CO_(2)/N_(2)/O_(2)和CO_(2)/N_(2)/O_(2)/H_(2)O等混合物的相包络线进行了预测,其对泡点、露点压力的计算与NIST(美国国家标准与技术研究院)方法计算结果的平均偏差小于3.5%,表明了CPA方程可作为一种简单且准确的含杂质CO_(2)混合体系相平衡计算方法。

Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic liquids and QSPR model

The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement ofγ∞by gas-liquid chromatography is a speedy and cost-saving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylben-zenes,styrene,in 1-allyl-3-methylimidazolium tetrafluorobo-rate([AMIM][BF4])and 1-butyl-3-methyl imidazolium hexafluorophosphate([BMIM][PF6]),1-isobutenyl-3-methylimidazolium tetrafluoroborate([MPMIM][BF4])and[MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure para-meters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.

Application of the quasi-random lattice model to rare-earth halide solutions for the computation of their osmotic and mean activity coefficients

This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated consistently, through the integration of the Gibbs-Duhem equation. Using of QRL was mainly motivated by its dependence on one parameter, given in the form of an electrolyte-dependent concentration, which was also the highest concentration at which the model could be applied. For all the electrolyte solutions here considered, this parameter was experimentally known and ranged from 1.5 to 2.2 mol/kg, at 25 ℃.Accordingly, rare- earth halide concentrations from strong dilution up to 2 mol/kg about could be considered without need for best-fit treatment in order to compute their osmotic and mean activity coefficients. The experimental knowledge about the parameter was an advantageous feature of QRL compared to existing literature models. Following a trend already observed with low charge electrolytes,a satisfactory agreement was obtained with the experimental values for all the investigated rare-earth chlorides and bromides. For the sake of compactness, in this work the considered rare-earth halides were all belonging to the P63/m space group in their crystalline（anhydrous） form.

Congregated electron phase and Wagner model applied in titanium distribution behavior in low-titanium slag

For studying the carbon thermal reduction rules of titanium in hot metal and providing a theoretical basis for the blast furnace（BF） hearth protection, the distribution behavior of titanium between low-titanium slag system of CaO-SiO2-MgO-Al2O3-TiO2 and hot metal was studied using analytical reagents in a temperature range from 1350 °C to 1600 °C. Through high temperature melting, rapid quenching, chemical analysis and thermodynamic model calculating, the results showed that the increase of reaction temperature, which improved the titanium distribution L（Ti） and lowered the system activity coefficient γsys, leads to the rise of equilibrium constant. Combined with Wagner and congregated electron phase models, the data obtained in distribution experiments were used to fit out the Gibbs free energy formula of titanium carbothermic reduction. Finally, the relations between the contents of Si and Ti in hot metal and the titanium load to reach the minimum w（Ti） for the formation of Ti C were given.

298.2 K下(CsBr+1,3-丁二醇+水)体系的热力学性质研究

盐湖卤水体系中含有重要的铯资源,开展含铯体系的热力学性质研究可以为盐湖卤水综合开发利用打下基础。文章采用铯离子选择性电极(Cs−ISE)和溴离子选择性电极(Br−ISE),组成电池Cs−ISE|CsBr(m),1,3-丁二醇(1,3-BD)(w),H_(2)O(1−w)|Br−ISE,测量了298.2 K时CsBr在(1,3-BD+H_(2)O)混合溶剂中的电动势,其中,1,3-BD在(1,3-BD+H_(2)O)混合溶剂中的质量分数w%=0,0.10,0.20,0.30。通过Nernst方程分别与Debye-Hückel模型和Pitzer模型相关联,得到了(CsBr+1,3-BD+H_(2)O)体系的热力学性质,包括平均离子活度系数(γ_(±))、过量吉布斯自由能(G^(E))和标准迁移吉布斯自由能(△G_(t)^(■))。结果表明,Debye-Hückel模型和Pitzer模型均能准确描述该体系。CsBr的活度系数γ±随混合体系中CsBr含量的增加而减小,当CsBr含量一定时,γ±随混合溶剂中1,3-BD含量的增加而减小。实验测得该体系的△G_(t)^(■)>0,说明CsBr从水中迁移到(1,3-BD+H_(2)O)混合溶剂的过程是非自发行为。

基于Modified Page函数和Box-Behnken响应面法的黄姜干燥参数优化

为优化热泵干燥黄姜片工艺,探究最佳干燥参数,以干燥温度、黄姜片厚度、出风速度三个为试验因素,采用Box-Behnken正交试验设计,确定黄姜片热泵干燥最佳工艺,计算每组试验中黄姜片的水分比,并采用PyCharm软件确定黄姜片热泵干燥的最佳数学模型。试验结果表明:干燥温度和黄姜片厚度对干燥速率影响较大,出风速度对干燥速率影响较小,整个干燥过程基本处于降速干燥,升速干燥时间较短。Box-Behnken正交试验得出最佳干燥工艺为温度63℃、黄姜片厚度2 mm、出风速度2 m/s。选取Lewis、Page、Modified Page、Henderson and Papis、Tow-term 5个薄层干燥常见数学模型,通过比较决定系数、离差平方和、均方根误差,确定Modified Page为干燥过程中最优模型。黄姜片的有效水分扩散系数与干燥温度、黄姜片厚度、出风速度具有正相关性,其值在1.46×10^(-8)~4.68×10^(-8)范围内变化,干燥活化能为39.71 kJ/mol。

A new model in correlating and calculating the solid–liquid equilibrium of salt–water systems

In this work, a new activity coefficient model was deduced for the correlation of solid–liquid equilibrium(SLE) in electrolyte solutions. The new excess Gibbs energy equation for SLE contains two parts: the single electrolyte item and the mixed electrolyte item. Then a new hypothesis for the reference state of activity coefficients was proposed in the work. Literature data for single electrolyte solution and mixed electrolyte solution systems,with temperature spanning from 273.15 to 373.15 K, were successfully correlated using the developed model.

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO_4-H_2O and NaF-H_2O binary solutions and NaClO_4-NaF-H_2O ternary solution

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions and NaClO4-NaF-H2O ternary strong electrolyte aqueous solutions was developed based on the ion and molecule coexistence theory （IMCT）. A transformation coefficient was needed to compare the calculated mass action concentration and the reported activity, because they were usually obtained at different standard states and concentration units. The results show that transformation coefficients between the calculated mass action concentrations and the reported activities of the same components change in a very narrow range. The transformed mass action concentrations of structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions agree well with the reported activities. The transformed mass action concentrations of structural units or ion couples in NaClO4-NaF-H2O ternary solution are also in good agreement with the reported activities in a total ionic strength range from 0.1 to 0.9 mol/kg H2O by the 0.1 mol/kg step with different ionic strength fractions of 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1, respectively. The results indicate that the developed thermodynamic model can reveal the structural characteristics of binary and ternary strong electrolyte aqueous solutions, and the calculated mass action concentrations of structural units or ion couples also strictly follow the mass action law.

Modified DIX model for ion-exchange equilibrium of L-phenylalanine on a strong cation-exchange resin

L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange （DIX） model, which takes the activiW into account, was established to predict the uptake of L-phenylalanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest t-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.

The Thermodynamic Model on Paraffin Wax Deposition Prediction

In process of crude oil production and transportation, wax and other solid deposition issues have a significant impact on oilfield production. Solid precipitation not only reduces the production efficiency and increases the cost of production. Therefore, there is a need to study the rate of paraffin wax deposition and cloud point temperature in order to guide the oil field control the paraffin wax deposition. In this paper, we use the Flory theory of polymer solution to correct the liquid activity coefficients, and regular solution theory to correct for the non ideality of the solid mixture, and we consider the impact of isoparaffin. Finally, thermodynamic model is established. The actual example calculation shows that the forecast results of this model are more accurate.

QUASI-CHEMICAL LOCAL COMPOSITION MODEL AND ITS EXAMINATION USING ADHESIVE HARD SPHERE MIXTURES

A local composition expression has been derived from the Guggenheim′s quasi-chemicalequation.On this basic a thermodynamic model,the quasi-chemical local composition model(QCLC)was established.To examine its capability for correlation and prediction,Baxter′s adhesivehard sphere mixtures were used,and an improved numerical method was proposed to estimate theirthermodynamic properties.By means of this method the excess properties of the mixtures composedof four kinds of adhesive hard spheres were calculated,The activity coefficients from QCLC modelwere compared with those from the Wilson,NRTL and UNIQUAC equations.Results show thatamong these models,the QCLC model is the best one for correlation and prediction.