A simple,reliable and fast algorithm for the simulation of multicomponent distillation columns

This work has developed a simple, reliable and fast algorithm for the simulation of multicomponent distillation columns, where any equilibrium stage can accept a feed-stream and/or a vapor-side-stream and/or liquid-side-stream. The new scheme considers internal molar overflows and constant relative volatilities to avoid the need of heat balances and vapor–liquid equilibrium calculations. The solution scheme is founded on a Newton-based formulation in block algebra, which relies in a simple, reliable and fast algorithm. Although the proposed calculation scheme can be classified as an approximate method, it is very useful when accurate phase equilibrium and enthalpy data are lacking. Numerical experimentations show good agreement with the results obtained with well-known rigorous simulation approaches.     

阻隔性高分子复合材料制备方法研究进展

阐述了阻隔性高分子复合材料的制备方法,包括表面处理法、多层复合法、层状共混法和纳米材料共混法,展望了阻隔性高分子复合材料的发展及应用前景。     

Dynamic real‐time optimization with closed‐loop prediction

Process plants are operating in an increasingly global and dynamic environment, motivating the development of dynamic real‐time optimization (DRTO) systems to account for transient behavior in the determination of economically optimal operating policies. This article considers optimization of closed‐loop response dynamics at the DRTO level in a two‐layer architecture, with constrained model predictive control (MPC) applied at the regulatory control level. A simultaneous solution approach is applied to the multilevel DRTO optimization problem, in which the convex MPC optimization subproblems are replaced by their necessary and sufficient Karush–Kuhn–Tucker optimality conditions, resulting in a single‐level mathematical program with complementarity constraints. The performance of the closed‐loop DRTO strategy is compared to that of the open‐loop prediction counterpart through a multi‐part case study that considers linear dynamic systems with different characteristics. The performance of the proposed strategy is further demonstrated through application to a nonlinear polymerization reactor grade transition problem. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3896–3911, 2017     

SYMBOLIC OPERATOR SOLUTIONS OF LAPLACE'S AND STOKES’ EQUATIONS PART I LAPLACE'S EQUATION

Symbolic operator techniques are employed to derive a general solution of Laplace's equation in the infinite space external to a sphere. This is done for the case where the function vanishes on the sphere surface and arbitrary continuous asymptotic boundary data are imposed at infinity, such data being prescribed in the form of a solution of Laplace's equation that is analytic at the origin. In contrast with other standard methods for solving Laplace's equation, e.g., Green's functions, eigenfunction expansions, etc., the novelty of the proposed method lies in the fact that the solution can be expressed in a completely explicit form, directly in terms of (radial derivatives of)the given “undisturbed” field at infinity

A reciprocal theorem is derived and used to demonstrate that certain integral properties of the field can be obtained directly from the prescribed data at infinity, without recourse to a detailed solution of the relevant boundary-value problem. This global symbolic operator technique is illustrated for ellipsoidal as well as spherical particles

The elementary scalar harmonic analysis of the present paper serves as an entré to a companion paper (Part II), concerned with the application of similar symbolic techniques to the solution of more difficult vector biharmonic boundary-value problems, relevant to hydrodynamic Stokes flows in the infinite region external to a particle.     

水泥生料中氨含量检测方法研究探索

本文主要探究了氯化钾溶液提取法和纳氏试剂法两种方法在水泥生料中氨含量检测的适应性和准确性,并进行了第三方检测验证。研究结果表明,氯化钾溶液提取法适用于0~50 mg/kg浓度的氨含量检测,而纳氏试剂法适用于20~100 mg/kg浓度的氨含量检测,本研究为水泥生料中氨含量检测提供指引和参考,对水泥工业实现氮氧化物超低排放,确保氨逃逸合格有着重要意义。     

The solubility of HCFC22, CFC114 and HFC152A in n-hexadecane

The solubilities of chlorodifluoromethane (HCFC22), 1, 2-dichlorotetrafluoroethane (CFC114) and 1,1-difluoroethane (HFC 152a) in n-hexadecane have been measured at temperatures between 303. 15 and 343. IS K and Henry's constants have been derived. The measurements were made with two different methods, a GLC method and an isochoric method. In general the results of the methods differ less than their combined margin of error, which is estimated to be less than 5% for the GLC method and less than 2% for the isochoric method.     

Solvothermal-derived multicomponent rare-earth cerate ceramics toward remarkable thermophysical properties

The multicomponent rare-earth cerate (Y_0.2La_0.2Nd_0.2Sm_0.2Eu_0.2)₂Ce₂O₇ (5RE₂Ce₂O₇) ceramics were successfully fabricated through solvothermal method and the following calcination process. The microstructure and phase composition of the as-obtained products were systematically characterized via SEM, TEM and XRD techniques. The results showed that the as-synthesised 5RE₂Ce₂O₇ has a single-phase fluorite-type crystal structure with the particle size of approximately 200 nm. Furthermore, the as-synthesised 5RE₂Ce₂O₇ demonstrated lower thermal conductivity (1.9–1.26 W m^?1·K^?1 at 25–1000 °C), higher thermal expansion coefficients (CTEs, 12.48 × 10^?6 K^?1 at 1000 °C), and outstanding mechanical properties including large Young's modulus (248.0 ± 0.35 GPa) and high fracture toughness (2.4 ± 0.21 MPam^1/2). The excellent properties of the as-synthesised 5RE₂Ce₂O₇ demonstrates its potential application as a new type of next-generation TBCs.     

Investigation of thermoluminescence and kinetic parameters of gamma ray exposed LiF: Sm3+, Eu3+ nanophosphors for dosimetric applications

Thermoluminescence (TL) properties of LiF: Sm³⁺ (0.05?mol%) co-doped with Eu³⁺ (0.02, 0.04, 0.06, 0.08?mol%) nanophosphor for the applications of TL dosimetry have been studied. The nanophosphors have been synthesized by chemical co-precipitation method at 8?pH value. The phase purity of the prepared samples has been confirmed by using X-ray diffraction (XRD) data. The XRD peaks broadening revealed the formation of the nanostructure, complemented by the TEM image. For TL studies, the samples have been irradiated with gamma rays using ⁶⁰Co source in the irradiation dose range of 0.1?kGy to 30?kGy. In gamma exposed samples, the TL glow curve consists of single glow peak at 410?K and three shoulder peaks at 475?K, 550?K and 632?K. The dosimetry properties such as the effects of exposure doses, heating rates and fading characteristics have also been studied. The kinetic parameters such as activation energy (E), the frequency factors (s) and order of kinetic (b) of the glow curves have also been calculated by using Chen's peak shape method. The linear behavior of TL intensity with radiation doses and low fading shows that the LiF: Sm³⁺, Eu³⁺ Nanophosphor is a potential candidate for dosimetry applications.     

Vapor liquid equilibrium data for alcohol n-Amylamine binary systems at 333.15 K. Reduction of the experimental data by a novel model-free method

Vapor liquid equilibrium measurements for the binary systems of n-amylamine with methanol, ethanol and 1-propanol at 333.15 K are reported. The measurements were made in a static equilibrium cell of the Van Ness type and the experimental data were reduced using a model-free method. This model-free method is an adaptation of the method of Mixon et al. in which a material balance is introduced to correct for the mols of the gas phase. Second virial coefficients of n-amylamine and cross second virial coefficients for the binary systems were measured in this work and parameters for the Tsonoupolos correlation are reported.