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    - CHEMICAL ENGINEERING (149 journals)
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    - ENGINEERING (1116 journals)
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    - MECHANICAL ENGINEERING (74 journals)

ENGINEERING (1116 journals)            First | 1 2 3 4 5 6 7 8 | Last

Biointerphases     Open Access  
Biomaterials Science     Full-text available via subscription   (Followers: 3)
Biomedical Engineering     Hybrid Journal   (Followers: 9)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 12)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 3)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 14)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 4)
Biomedical Microdevices     Hybrid Journal   (Followers: 7)
Biomedizinische Technik - Biomedical Engineering     Full-text available via subscription  
Biomicrofluidics     Open Access   (Followers: 2)
BioNanoMaterials     Full-text available via subscription   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 20)
Boletin Cientifico Tecnico INIMET     Open Access  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access  
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bubble Science, Engineering & Technology     Hybrid Journal  
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 1)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 11)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 3)
Case Studies in Thermal Engineering     Open Access   (Followers: 1)
Catalysis Communications     Hybrid Journal   (Followers: 4)
Catalysis Letters     Hybrid Journal   (Followers: 1)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 4)
Catalysis Science and Technology     Free   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 6)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 1)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 1)
Chinese Journal of Engineering     Open Access  
Chinese Science Bulletin     Open Access  
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access  
Ciencias Holguin     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 10)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 9)
City, Culture and Society     Hybrid Journal   (Followers: 17)
Clay Minerals     Full-text available via subscription   (Followers: 3)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Clinical Science     Full-text available via subscription   (Followers: 3)
Coal Science and Technology     Full-text available via subscription   (Followers: 2)
Coastal Engineering     Hybrid Journal   (Followers: 7)
Coastal Engineering Journal     Hybrid Journal   (Followers: 1)
Coatings     Open Access   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 3)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 4)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 9)
Communications Engineer     Hybrid Journal  
Communications in Information Science and Management Engineering     Open Access   (Followers: 7)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 3)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Composite Interfaces     Hybrid Journal   (Followers: 3)
Composite Structures     Hybrid Journal   (Followers: 33)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 27)
Composites Part B : Engineering     Hybrid Journal   (Followers: 24)
Composites Science and Technology     Hybrid Journal   (Followers: 32)
Comptes Rendus Mécanique     Full-text available via subscription  
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 10)
Computational Optimization and Applications     Hybrid Journal   (Followers: 5)
Computational Science and Discovery     Full-text available via subscription  
Computational Water, Energy, and Environmental Engineering     Open Access   (Followers: 1)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 5)
Computers & Geosciences     Hybrid Journal   (Followers: 6)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 4)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 3)
Computers and Geotechnics     Hybrid Journal   (Followers: 5)
Computing and Visualization in Science     Hybrid Journal   (Followers: 3)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 10)
Conciencia Tecnologica     Open Access   (Followers: 1)
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continental Journal of Applied Sciences     Open Access   (Followers: 4)
Continental Journal of Engineering Sciences     Open Access   (Followers: 2)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 3)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 4)
Control Engineering Practice     Hybrid Journal   (Followers: 10)
Control Theory and Informatics     Open Access   (Followers: 4)
Corrosion Science     Hybrid Journal   (Followers: 18)
Corrosion Series     Full-text available via subscription   (Followers: 5)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Dams and Reservoirs     Hybrid Journal   (Followers: 2)
Data Handling in Science and Technology     Full-text available via subscription   (Followers: 2)
Design Journal     Full-text available via subscription   (Followers: 14)
Designed Monomers and Polymers     Hybrid Journal   (Followers: 2)
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 4)

  First | 1 2 3 4 5 6 7 8 | Last

Journal Cover AIChE Journal
   [18 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0001-1541 - ISSN (Online) 1547-5905
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 0.889]   [H-I: 94]
  • Practical challenges in the energy‐based control of molecular
           transformations in chemical reactors
    • Authors: Izabela Szydłowska Franssen; Daniel Irimia, Georgios D. Stefanidis, Andrzej I. Stankiewicz
      Pages: n/a - n/a
      PubDate: 2014-08-12T13:42:45.863869-05:
      DOI: 10.1002/aic.14575
  • Global optimality properties of total annualized and operating cost
           problems for compressor sequences
    • Authors: Jeremy A. Conner; Vasilios I. Manousiouthakis
      Pages: n/a - n/a
      Abstract: In this work, the minimum total annualized cost problem is studied for a series of non‐isentropic compressors and coolers that brings a gas with constant compressibility factor from a specified initial pressure and temperature to a specified final pressure and the same temperature. It is established analytically that at the global optimum, the cooler outlet temperatures are equal to the minimum allowable temperature. For constant heat capacity, constant compressibility factor gases, additional properties of the globally optimal compressor sequence are analytically established for the minimum operating cost case. The aforementioned properties permit development of a solution strategy that identifies the globally‐minimum operating cost. Several case studies are presented to illustrate the developed theorems and solution strategies. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-11T09:40:36.178594-05:
      DOI: 10.1002/aic.14580
  • Distributed Lyapunov‐based model predictive control with
           neighbor‐to‐neighbor communication
    • Authors: Su Liu; Jinfeng Liu
      Pages: n/a - n/a
      Abstract: We consider distributed predictive control of large‐scale nonlinear systems with neighbor‐to‐neighbor communication. This work fulfills the gap between the existing centralized Lyapunov‐based MPC (LMPC) and the cooperative distributed LMPC and provides a balanced solution in terms of implementation complexity and achievable performance. We focus on a class of nonlinear systems with subsystems interacting with each other via their states. For each subsystem, an LMPC is designed based on the subsystem model and the LMPC only communicates with its neighbors. At a sampling time, a subsystem LMPC optimizes its future control input trajectory assuming that the states of its upstream neighbors remain the same as (or close to) their predicted state trajectories obtained at the previous sampling time. Both non‐iterative and iterative implementation algorithms are considered. The performance of the proposed designs are illustrated via a chemical process example. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-11T06:12:03.418863-05:
      DOI: 10.1002/aic.14579
  • Modified gas‐translation model for prediction of gas permeation
           through microporous organosilica membranes
    • Authors: Hiroki Nagasawa; Takuya Niimi, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
      Pages: n/a - n/a
      Abstract: A modified gas‐translation (GT) model was applied for the theoretical analysis of gas permeation through microporous organosilica membranes derived from bis(triethoxysilyl)ethane (BTESE) via a sol‐gel method using different water/alkoxide molar ratios. The pore sizes of BTESE‐derived membranes were quantitatively determined by Normalized Knudsen‐based Permeance (NKP) analysis, which was based on a modified‐GT model, using experimentally obtained permeances of He, H2, N2, C3H8, and SF6. The pore sizes of BTESE‐derived membranes were successfully controlled from 0.65 to 0.46 nm by increasing the H2O/BTESE ratio from 6 to 240. Furthermore, theoretical correlations of all possible pairs of permeance ratios were calculated based on the modified‐GT model. The experimental data were in good agreement with the theoretical correlation curves, indicating that the modified‐GT model can clearly explain gas permeation mechanisms through microporous membranes, and, thus, can be used to predict the gas permeation properties for these membranes. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-11T06:06:22.375282-05:
      DOI: 10.1002/aic.14578
  • Mechanism and kinetic modeling for steam reforming of toluene on
           La0.8Sr0.2Ni0.8Fe0.2O3 catalyst
    • Authors: Usman Oemar; Ang Ming Li, Kus Hidajat, Sibudjing Kawi
      Pages: n/a - n/a
      Abstract: Reaction mechanism for steam reforming of toluene is proposed for La0.8Sr0.2Ni0.8Fe0.2O3 (LSNFO) perovskite catalyst. The proposed mechanism was derived from various characterization results such as TPD and TPSR water, TPSR toluene, TPD O2 and in‐situ DRIFT of toluene decomposition and steam reforming of toluene. Five kinetic models were developed based on the proposed dual‐site reaction mechanism using Langmuir‐Hinshelwood (LH) approach. Subsequently, the parameters of the kinetic models were estimated by non‐linear least square regression. A good agreement was obtained between experimental and model predicted results for the rate determining step (RDS) based on reaction between adsorbed aldehyde and adsorbed oxygen. The adsorbed aldehyde species is produced from the reaction between adsorbed C2H2 or CH2 and adsorbed oxygen while the adsorbed oxygen species can come from the oxygen from water activation, lattice oxygen species, and/or the redox property of some metals such as Fe. This shows that the adsorbed oxygen species plays important role in this reaction. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-11T05:36:59.473292-05:
      DOI: 10.1002/aic.14573
  • A numerical study of dynamic capillary pressure effect for supercritical
           carbon dioxide‐water flow in porous domain
    • Authors: Diganta B. Das; Bhupinder S. Gill, Luqman K. Abidoye, Kamal Khudaida
      Pages: n/a - n/a
      Abstract: Numerical simulations for core‐scale capillary pressure (Pc)–saturation (S) relationships have been conducted for a supercritical carbon dioxide‐water system at temperatures between 35°C and 65°C at a domain pressure of 15 MPa as typically expected during geological sequestration of CO2. As the Pc‐S relationships depend on both S and time derivative of saturation (∂S / ∂t) yielding what is known as the ‘dynamic capillary pressure effect’ or simply ‘dynamic effect’, this work specifically attempts to determine the significance of these effects for supercritical carbon dioxide‐water flow in terms of a coefficient, namely dynamic coefficient (τ). The coefficient establishes the speed at which capillary equilibrium for supercritical CO2‐water flow is reached. The simulations in this work involved the solution of the extended version of Darcy’s law which represents the momentum balance for individual fluid phases in the system, the continuity equation for fluid mass balance, as well as additional correlations for determining the capillary pressure as a function of saturation, and the physical properties of the fluids as a function of temperature. The simulations were carried for 3D cylindrical porous domains measuring 10 cm in diameter and 12 cm in height. τ was determined by measuring the slope of a best‐fit straight line plotted between (i) the differences in dynamic and equilibrium capillary pressures (Pc,dyn – Pc,equ) against (ii) the time derivative of saturation (dS/dt), both at the same saturation value. The results show rising trends for τ as the saturation values reduce, with noticeable impacts of temperature at 50% saturation of aqueous phase. This means that the time to attain capillary equilibrium for the CO2‐water system increases as the saturation decreases. From a practical point view, it implies that the time to capillary equilibrium during geological sequestration of CO2 is an important factor and should be accounted for while simulating the flow processes, e.g., to determine the CO2 storage capacity of a geological aquifer. In this task, one would require both the fundamental understanding of the dynamic capillary pressure effects for supercritical CO2‐water flow as well as τ values. These issues are addressed in this article. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-08T11:58:12.148498-05:
      DOI: 10.1002/aic.14577
  • Near‐wall convection in a sedimenting suspension of fibres
    • Authors: Feng Zhang; Katarina Gustavsson, Fredrik Lundell, Anders A. Dahlkild
      Pages: n/a - n/a
      Abstract: The sedimentation of a fibre suspension near a vertical wall is investigated numerically. Initially, the near‐wall convection is an upward backflow, which originates from the combined effects of the steric‐depleted layer and a hydrodynamically‐depleted region near the wall. The formation of the hydrodynamically‐depleted region is elucidated by a convection‐diffusion investigation, in which fibres are classified according to the different directions in which they drift. For fibres with sufficiently large aspect ratio, the initial near‐wall backflow keeps growing. However, the backflow reverses to downward flow at later times if the aspect ratio is small. This is due to the fibre‐wall interactions which rotate fibres to such angles that make fibres drift away from the wall, inducing a dense region and a correspondingly downward flow outside the initial backflow. Moreover, the steric‐depleted boundary condition is of secondary importance in the generation and evolution of the near‐wall convection. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-08T11:35:18.80853-05:0
      DOI: 10.1002/aic.14576
  • Analysis of plug flow reactors with variable mass density
    • Authors: J. S. Vrentas; C. M. Vrentas
      Pages: n/a - n/a
      Abstract: The design of plug flow reactors with variable mass density is examined. Equations which include a two‐term constitutive equation for the reaction rate are derived for the flow of liquids and for the flow of ideal gases in steady plug flow reactors. It is shown that the addition of the second term in the constitutive equation can have a significant effect on the calculation of the reactor volume needed to carry out a specific conversion of the reactant. Published experimental plug flow reactor data support the observation that a reaction rate constitutive equation with two terms can provide a good representation of the experimental data for variable mass density reactors. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-06T07:35:05.487258-05:
      DOI: 10.1002/aic.14574
  • Influence of loading rate and pre‐loading on the mechanical
           properties of dry elasto‐plastic granules under compression
    • Authors: Alexander Russell; Peter Müller, Hao Shi, Jürgen Tomas
      Pages: n/a - n/a
      Abstract: In order to ensure high quality of granular products post‐industrial operations, it is necessary to precisely define their micro‐macro mechanical properties. However, such an endeavor is arduous, owing to their highly inhomogeneous, anisotropic and history‐dependent nature. In this article, we present the distributed granular micro‐ and macro‐mechanical, energetic and breakage characteristics using statistical distributions. We describe the material behavior of elasto‐plastic zeolite 4AK granules under uniaxial compressive loading until primary breakage, and localized cyclic loading up to different maximum force levels, at different displacement‐controlled loading rates. The observed force‐displacement behavior had been approximated and further evaluated using well‐known contact models. The results provide the basis for a detailed analysis of the viscous behavior of zeolite 4AK granules in the moist and wet states, indicating that higher compressive loads are required at higher displacement‐controlled loading rates to realize equivalent deformation and breakage probability achieved by loads at lower displacement‐controlled loading rates. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-04T06:00:36.692376-05:
      DOI: 10.1002/aic.14572
  • Continuous flow characterization of solid biomass in a
           reciprocating/rotating scraper tube: An experimental study
    • Authors: Kamelia V.K. Boodhoo; Lily Smith, Juan Pedro Solano, Mark Gronnow, James Clark
      Pages: n/a - n/a
      Abstract: The performance of reciprocating/rotating scrapers has been assessed in a visualization study of the continuous flow hydrodynamics of air‐fluidized solid biomass under varying conditions of air flow rate and scraping velocities. A combination of low air flow rates and high scraping velocities result in more uniform flow of both types of biomass investigated. Power consumed by the reciprocating action of the scrapers increases with the scraping velocity but typically represents no more than 20% of the overall power consumption at the highest air flow rate applied. We also demonstrate that rotation of the scrapers superimposed on their reciprocating action gives higher flow rate of biomass and better mixing within the bulk solid compared to reciprocating action alone. The application of the reciprocating/rotating scraper technology described in this study represents a viable step forward in developing a continuous, large‐scale process for the microwave‐assisted decomposition of solid biomass to produce bio‐oils. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-04T05:20:37.661511-05:
      DOI: 10.1002/aic.14571
  • Analytical models of penetration depth during slot die coating onto porous
    • Authors: Xiaoyu Ding; Zhuo Li, Joshua Prince Ebin, Thomas F. Fuller, Tequila A.L. Harris
      Pages: n/a - n/a
      Abstract: A series of analytical models have been developed to predict the penetration depth during slot die coating on porous media. Analytical models for both Newtonian and non‐Newtonian fluids were derived based on Lubrication Theory, Darcy’s law, and a modified Blake‐Kozeny equation. Using these models, the penetration depth can be quickly solved and the effects of material properties and processing conditions on penetration depth can be easily investigated. Experiments of coating Newtonian glycerin and non‐Newtonian blackstrap molasses onto Toray series carbon paper were conducted to validate developed models. The overall relative error between the predicted and measured penetration depth was found to be typically lower than 20%, which demonstrates the relative accuracy of developed models. Furthermore, based on a parametric study, it was found that the effect of capillary pressure on penetration depth is less than 10% when the ratio of coating bead pressure and capillary pressure is larger than 10. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-01T10:49:24.54136-05:0
      DOI: 10.1002/aic.14570
  • Experimental investigation of continuous single‐phase rimming flow
           in a horizontal rotating cylinder
    • Authors: Saravanan Suppiah Singaram; Roshan J Jachuck, Himanshu Lodha
      Pages: n/a - n/a
      Abstract: Rimming flow of water that leads to a thin film onto the inner surface of a horizontally rotating cylinder is studied in this work. At higher rotational speeds, axial flow of uniform thin film is established inside the rotating cylinder. Film thickness measurements under different flow conditions were performed in the annular flow regime using an optical interferometric technique. Dimensional analysis was also performed to understand the parametric dependence of key parameters involved in the rimming flow of water inside a horizontal rotating cylinder and expressions to determine average film thickness and average residence time are also presented. This current study will provide a basis to estimate the transport characteristics in the thin film inside the horizontal rotating cylinder. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-08-01T05:36:07.46609-05:0
      DOI: 10.1002/aic.14569
  • Formation of defect-free polyetherimide/PIM-1 hollow fiber membranes for
           gas separation
    • Authors: Lin Hao; Jian Zuo, Tai-Shung Chung
      Pages: n/a - n/a
      Abstract: Dual-layer hollow fiber membranes were produced from blends of Ultem and polymer of intrinsic microporosity (PIM-1) with enhanced gas permeance. The effects of spinning parameters (take-up speed and air gap distance) on gas separation performance were investigated based on the pristine Ultem. Selected spinning conditions were further adopted for the blend system, achieving defect-free and almost defect-free hollow fibers. Adding PIM results in a higher fractional free volume, 50% increments in gas permeance were observed for Ultem/PIM-1 (95/5) and more than 100% increments for Ultem/PIM-1 (85/15). Both O2/N2 and CO2/CH4 selectivities remained the same for Ultem/PIM-1 (95/5) and above 80% of their respective intrinsic values for Ultem/PIM-1 (85/15). The selective layer thickness ranges from 70 to 120 nm, indicating the successful formation of ultrathin dense layers. Moreover, minimum amounts of the expensive material were consumed, that is, 0.88, 1.7, and 2.3 wt % PIM-1 for Ultem/PIM-1 (95/5), (90/10), and (85/15), respectively. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-28T14:09:07.6357-05:00
      DOI: 10.1002/aic.14565
  • Model reduction for linear simulated moving bed chromatography systems
           using Krylov-subspace methods
    • Authors: Suzhou Li; Yao Yue, Lihong Feng, Peter Benner, Andreas Seidel-Morgenstern
      Pages: n/a - n/a
      Abstract: Simulated moving bed (SMB) chromatography is a well-established technology for separating chemical compounds. To describe an SMB process, a finite-dimensional multistage model arising from the discretization of partial differential equations is typically employed. However, its relatively high dimension poses severe computational challenges to various model-based analysis. To overcome this challenge, two Krylov-type model order reduction (MOR) methods are proposed to accelerate the computation of the cyclic steady states (CSSs) of SMB processes with linear isotherms. A “straightforward method” that carefully deals with the switching behavior in MOR is first proposed. Its improvement, a “subspace-exploiting method,” thoroughly exploits each reduced model to achieve further acceleration. Simulation studies show that both methods achieve high accuracy and significant speedups. The subspace-exploiting method turns out to be computationally much more efficient. Two challenging analyses of SMB processes, namely uncertainty quantification and CSS optimization, further demonstrate the accuracy, efficiency, and applicability of the proposed methods. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-28T14:03:09.521068-05:
      DOI: 10.1002/aic.14561
  • Experimental validation of a flexible modeling approach for distillation
           columns with packings
    • Authors: Christoph Ehlers; Georg Fieg
      Pages: n/a - n/a
      Abstract: The two main concepts for the modeling of distillation columns are the equilibrium-stage (EQ) and the nonequilibrium-stage (NEQ). A model is presented which combines decisive features of both conventional concepts. Based on the idea of a reduced nonequilibrium-stage (RNEQ), this model can be used for the simulation of distillation columns with packings. In contrast to the conventional NEQ approach, this model neglects the influence of liquid side mass-transfer coefficients, which ultimately allows to come up with only one empirical equation describing the overall mass transfer. Thus, a considerable reduction in model complexity is reached, which allows for an efficient consideration of new experimental distillation results. Fitted to experimental data, the model is able to predict, how different pressures and chemical systems might affect the separation efficiency. By comparing calculation results with experimentally determined separation efficiencies for three different packing types, these valuable RNEQ qualities are illustrated. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T13:22:23.478698-05:
      DOI: 10.1002/aic.14560
  • Mixing potential: A new concept for optimal design of hydrogen and water
           networks with higher disturbance resistance
    • Authors: Zuwei liao; Junyi Lou, Jingdai Wang, Binbo Jiang, Yongrong Yang
      Pages: n/a - n/a
      Abstract: During the last decade, the design methods of hydrogen and water networks have been improved greatly. Since the resulting network structure featuring minimum utility consumption is not unique, other properties such as disturbance resistance have drawn more and more attention. In this article, a novel concept, Mixing Potential, is proposed to improve the disturbance resistance ability of the networks in the design stage. This concept originates from measuring the concentration fluctuation of a single sink, and could be calculated by its graphical and algorithmic definition, respectively. In addition, a sufficient condition for minimizing the Mixing Potential of a single sink has been proved. Based on this sufficient condition, a graphical and its corresponding algorithmic method are proposed to design the hydrogen and water networks with minimum utility consumption. Literature examples illustrate that the disturbance resistance ability of the network can be improved by adjusting the satisfying order of sinks. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T13:22:01.598619-05:
      DOI: 10.1002/aic.14556
  • Framework for correlating the effect of temperature on nonelectrolyte and
           ionic liquid activity coefficients
    • Authors: Timothy C. Frank; Steven G. Arturo, Bruce S. Holden
      Pages: n/a - n/a
      Abstract: A power-law expression is proposed for correlating the temperature dependence of infinite-dilution activity coefficients ( γij∞) for nonelectrolyte solute–solvent binary pairs and for pairs including an ionic liquid: ln⁡γij∞(at T)/ln⁡γij∞(at Tref)=(Tref/T)θij, where θij = 0 for Lewis–Randall ideal solutions, θij = 1 for classic enthalpy-based Scatchard–Hildebrand regular solution and van Laar models, and −5 
      PubDate: 2014-07-24T13:16:26.501557-05:
      DOI: 10.1002/aic.14557
  • Impact of separator’s solid phase ion conductivity parameter on
           convection battery performance and modeling
    • Authors: R. Hilton; M. Gordon, D. Dornbusch, G. J. Suppes
      Pages: n/a - n/a
      Abstract: A solid phase ion conductivity parameter has been added to the separator of a porous electrode theory description of a convection battery performance to increase the accuracy of this model. With the addition of the ion conductivity parameter, the variances between the model and experimental data have been reduced by 80-85% in both the convection cell and the diffusion cell. The parameter is fundamentally consistent with solid phase mechanisms by which ions can transport through separators in parallel with liquid phase transport, and the improved modeling results substantiate the importance of solid or surface ion transport mechanisms at high current fluxes. Modeling was supplemented with dimensionless analysis to lump fundamental parameters that are inherently coupled in the underlying equations. From this analysis, a global parameter has been developed describing the ratio of convective charge transfer to diffusive charge transfer that characterizes the transition from diffusive to convective cell behavior. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T01:02:05.521355-05:
      DOI: 10.1002/aic.14568
  • Equation-oriented flowsheet simulation and optimization using
           pseudo-transient models
    • Authors: Richard C. Pattison; Michael Baldea
      Pages: n/a - n/a
      Abstract: Tight integration through material and energy recycling is essential to the energy efficiency and economic viability of process and energy systems. Equation-oriented steady state process simulation and optimization are key enablers in the optimal design of integrated processes. In this paper a new process modeling and simulation concept based on pseudo-transient continuation is introduced. We present an algorithm for reformulating the steady-state models of process unit operations as differential-algebraic equation (DAE) systems that are statically equivalent with the original model. We show that these pseudo-transient models improve the convergence of equation-oriented process flowsheet simulations by expanding the convergence basin. We use this concept to build a library of pseudo-transient models for common process unit operations, and show that this modeling concept seamlessly integrates with a previously developed time-relaxation optimization algorithm. Two design case studies are presented to validate the proposed framework. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-24T00:28:29.260326-05:
      DOI: 10.1002/aic.14567
  • Structure-property Relationship of pH-sensitive (PCL)2(PDEA-b-PPEGMA)2
           micelles: Experiment and DPD simulation
    • Authors: Wen JingLin; Shu YuNie, Quan Chen, Yu Qian, Xiu FangWen, Li Juan Zhang
      Pages: n/a - n/a
      Abstract: The experiment and dissipative particle dynamics (DPD) simulation were carried out on four polymers with different block ratios for the investigation of the structure-property relationship of (poly(ε-caprolactone)2-[poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate)]2 [(PCL)2(PDEA-b-PPEGMA)2] micelles. The miktoarm star polymers assembled into spherical micelles composed of PCL core, pH-sensitive PDEA mesosphere and PPEGMA shell. When decreasing pH from 7.4 to 5.0, the hydrodynamic diameter and transmittance of (PCL)2(PDEA-b-PPEGMA)2 micelles increased along with globule-uneven-extended conformational transitions, owing to the protonation of tertiary amine groups of DEA at lower pH conditions. Doxorubicin (DOX) was mainly loaded in the pH-sensitive layer, and more DOX were loaded in the core when increasing drug concentrations. The in vitro DOX release from the micelles was significantly accelerated by decreasing pH from 7.4 to 5.0. The results demonstrated that the pH-sensitive micelles could be used as an efficient carrier for hydrophobic anticancer drugs, achieving controlled and sustained drug release. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-22T03:30:49.283386-05:
      DOI: 10.1002/aic.14562
  • Polypropylene in the melt state as a medium for in situ synthesis of
           copper nanoparticles
    • Authors: Humberto Palza; Katherine Delgado, Natalia Moraga, Sing-Hi Wang Molina
      Pages: n/a - n/a
      Abstract: Copper nanoparticles were in situ synthesized into a polypropylene matrix in the melt state. Three different routes were studied depending on the method used for the addition of a copper salt: (1) directly as powder; (2) dissolved in water; and (3) dissolved in water with a reducing agent. The first route produced microcrystal, whereas the second route allowed the synthesis of nanoparticles (∼20 nm) homogeneously dispersed in the polymer matrix. By changing the concentration of the reducing agent in the copper solution (third route), a control of the copper structure in the polymer was possible and salt-based or metal/oxide nanoparticles could be obtained. All these composites were able to release copper ions depending on the characteristic of the nanoparticles present in the polymer. Noteworthy, the resulting polymer/copper composites displayed strong antimicrobial behavior against Escherichia coli. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-21T11:03:38.13524-05:0
      DOI: 10.1002/aic.14549
  • Phase Equilibria and Structural Properties of Thiophene/[Bmim][BF4]: A
           Molecular Insight from Monte Carlo Simulations
    • Authors: Yongping Zeng; Chunfeng Wang, Yueyang Xu, Junmei Hu, WenLin Xu, Shengui Ju
      Pages: n/a - n/a
      Abstract: The phase equilibria of thiophene in 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) is calculated by Monte Carlo simulation in Gibbs ensemble using a united atom force field. The liquid density of studied ionic liquid and the vapor pressure of thiophene in [Bmim][BF4] were compared with corresponding experimental data reported in the literature, and a good agreement was obtained. In order to describe the solubility of thiophene in this ionic liquid, we have calculated the radial distribution functions and spatial distribution functions of thiophene/IL mixtures to study the interaction of thiophene with cations and anions of [Bmim][BF4] in the liquid phase. The local composition concept in fluid was also examined to give further insight into the liquid structure. The results show that thiophene is well organized around the terminal carbon atom of the butyl or methyl chain attached to the imidazolium ring of cations and tends to adopt a symmetrically distribution on the anions. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-21T05:24:07.325795-05:
      DOI: 10.1002/aic.14566
  • A lattice Boltzmann simulation of mass transport through composite
    • Authors: Li-Zhi Zhang
      Pages: n/a - n/a
      Abstract: Composite membranes with a porous support layer and a dense skin layer have been extensively used in gas separation processes. In this study, a new approach, a meso-scale Lattice Boltzmann Simulation approach (LBM), is proposed and used to model the pore-scale gas flow and mass transfer in the inhomogeneous membrane matrixes. Only physical forces are considered. Chemical forces are equivalently converted to physical forces through the relaxation time. Selective permeation of moisture through a composite membrane is modeled. The overall permeability is evaluated. It is found that mass transfer inhomogeneity exists not only in the porous media, but also in the seemingly uniform dense skin layer. Increasing the diffusivity in the skin layer is more effective than decreasing the skin layer thickness in optimizing the overall membrane performance. The new approach gives more detailed insights into the directions for future design of composite membranes for gas separations like air dehumidification. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-19T06:59:00.05676-05:0
      DOI: 10.1002/aic.14564
  • The adjustable synergistic effects between acid-base coupling bifunctional
           ionic liquid extractants for rare earth separation
    • Authors: Xiaoqi Sun; Kristian E Waters
      Pages: n/a - n/a
      Abstract: Two of the most widely used industrial extractants for rare earth elements (REEs), i.e., di(2-ethylhexyl)phosphoric acid (HDEHP) and 2-ethyl(hexyl) phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) were developed into [DEHP]- type acid-base coupling bifunctionalized ionic liquids (ABC-BILs) and [EHEHP]- type ABC-BILs, respectively. The combinations of ABC-BIL extractants revealed obviously synergistic effects for REEs. Seven different combinations of ABC-BILs and five kinds of REEs confirmed the novel synergistic extraction. Some synergy coefficients of the combined ABC-BILs were bigger than those of mixed HDEHP and HEH[EHP] by two orders of magnitude. This paper reports the first synergistic extraction produced by ionic liquid extractants in the field of solvent extraction. The novel synergistic extraction from combined ABC-BILs extractants revealed highly efficient and environmentally friendly potential in both of academic research and industrial application for REEs separation. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-19T03:06:18.682879-05:
      DOI: 10.1002/aic.14563
  • Microwave assisted flow synthesis: Coupling of electromagnetic and
           hydrodynamic phenomena
    • Authors: Narendra G. Patil; Faysal Benaskar, Jan Meuldijk, Lumbertus A. Hulshof, Volker Hessel, Jaap C. Schouten, Erik D. C. Esveld, Evgeny V. Rebrov
      Pages: n/a - n/a
      Abstract: This article describes the results of a modeling study performed to understand the microwave heating process in continuous-flow reactors. It demonstrates the influence of liquid velocity profiles on temperature and microwave energy dissipation in a microwave integrated milli reactor-heat exchanger. Horizontal cocurrent flow of a strong microwave absorbing reaction mixture (ethanol + acetic acid, molar ratio 5:1) and a microwave transparent coolant (toluene) was established in a Teflon supported quartz tube (i.d.: 3 × 10−3 m and o.d.: 4 × 10−3 m) and shell (i.d.: 7 × 10−3 m and o.d.: 9 × 10−3 m), respectively. Modeling showed that the temperature rise of the highly microwave absorbing reaction mixture was up to four times higher in the almost stagnant liquid at the reactor walls than in the bulk liquid. The coolant flow was ineffective in controlling the outlet reaction mixture temperature. However, at high flow rates it limits the overheating of the stagnant liquid film of the reaction mixture at the reactor walls. It was also found that the stagnant layer around a fiber optic temperature probe, when inserted from the direction of the flow, resulted in much higher temperatures than the bulk liquid. This was not the case when the probe was inserted from the opposite direction. The experimental validations of these modeling results proved that the temperature profiles depend more on the reaction mixture velocity profiles than on the microwave energy dissipation/electric field intensity. Thus, in flow synthesis, particularly where a focused microwave field is applied over a small tubular flow reactor, it is very important to understand the large (direct/indirect) influence of reactor internals on the microwave heating process. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T13:35:33.306397-05:
      DOI: 10.1002/aic.14552
  • A novel hybrid feedstock to liquids and electricity process: Process
           modeling and exergoeconomic life cycle optimization
    • Authors: Chang He; Fengqi You, Xiao Feng
      Pages: n/a - n/a
      Abstract: This article proposes a novel hybrid low-rank coal (LRC)/biomass/natural gas process for producing liquid fuels and electricity. The hybrid process highlights coexistence of indirect and direct liquefaction technologies, cogasification of char and biomass, and corefinery of LRC syncrude and Fischer–Tropsch syncrude. A process simulation based on detailed chemical kinetics is present to illustrate its feasibility. In addition, we propose an exergoeconomic life cycle optimization framework that seeks to maximize the primary exergy saving ratio, primary total overnight cost saving ratio, life cycle waste emissions avoidance ratio, and primary levelized cost saving ratio by comparing the proposed hybrid process to its reference stand-alone subsystems. From the results, we can determine four optimal designs which yield competitive breakeven oil prices ranging from $1.87/GGE to $2.13/GGE. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T13:32:34.589941-05:
      DOI: 10.1002/aic.14551
  • Enhancement of flux and solvent stability of Matrimid® thin-film
           composite membranes for organic solvent nanofiltration
    • Authors: Shi-Peng Sun; Tai-Shung Chung, Kang-Jia Lu, Sui-Yung Chan
      Pages: n/a - n/a
      Abstract: The development of high flux and solvent-stable thin-film composite (TFC) organic solvent nanofiltration (OSN) membranes was reported. A novel cross-linked polyimide substrate, consisting of a thin skin layer with minimum solvent transport resistance and a sponge-like sublayer structure that could withstand membrane compaction under high-pressure was first fabricated. Then the solvent flux was significantly enhanced without compromising the solute rejection by the coupling effects of (1) the addition of triethylamine/camphorsulfonic acid into the monomer solution, and (2) the combined post-treatments of glycerol/sodium dodecyl sulphate immersion and dimethyl sulfoxide (DMSO) filtration. Finally, the long-term stability of the TFC membrane in aprotic solvents such as DMSO was improved by post-crosslink thermal annealing. The novel TFC OSN membrane developed was found to have superior rejection to tetracycline (MW: 444 g/mol) but was very permeable to alcohols such as methanol (5.12 lm−2h−1bar−1) and aprotic solvents such as dimethylformamide (3.92 lm−2h−1bar−1) and DMSO (3.34 lm−2h−1bar−1). © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T11:07:45.512646-05:
      DOI: 10.1002/aic.14558
  • Reconstruction of transcription factor profiles from fluorescent protein
           reporter systems via dynamic optimization and Tikhonov regularization
    • Authors: Wei Dai; Juergen Hahn, Jia Kang
      Pages: n/a - n/a
      Abstract: This work presents a generally applicable technique for reconstructing transcription factor (TF) profiles from fluorescence microscopy images of green fluorescent protein reporter systems. The approach integrates dynamic optimization and a Tikhonov regularization to avoid over-fitting caused by the highly ill-conditioned structure of this inverse problem. The advantage that the presented approach has over existing methods is that no assumptions are made about the TF profile, the linearity, or lack thereof, of the dynamic model used, and the sampling time of the measurements. Moreover, the method allows to use discretization times for the model different from the measurement sampling times and can also deal with state constraints. The technique has been applied to both simulated and experimental data where the profile of the TFs NF-κB and STAT3 are reconstructed. In both of the case studies, the presented approach exhibits excellent performance while fewer assumptions are needed than for existing techniques. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-18T11:04:28.555781-05:
      DOI: 10.1002/aic.14559
  • Effect of impeller design and power consumption on crystal size
    • Authors: Chinmay V. Rane; Kalekudithi Ekambara, Jyeshtharaj B. Joshi, Doraiswami Ramkrishna
      Pages: n/a - n/a
      Abstract: Crystallization processes in a 500 mL stirred tank crystallizer with computational fluid dynamics (CFD) and population balances toward estimating how crystal size distributions (CSDs) are influenced by flow inhomogeneities was explored. The flow pattern and CSD are presented here though extensive phase Doppler particle analyzer measurements and CFD predictions for three different impeller designs (disc turbine, pitched blade turbine, and Propeller) and each rotated at three different speeds (2.5, 5, and10 r/s). As crystallization processes in practice could involve break-up and aggregation of crystals, some selected break-up and aggregation kernels are incorporated. Extensive comparison of simulations with experimental data showed consistent trends in the proper quantitative range. An attempt has also been made to develop scaling laws: (a) mean particle size with average power consumption per unit mass and (b) particle-size distribution with the turbulent energy dissipation distribution. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-07-16T14:14:53.653545-05:
      DOI: 10.1002/aic.14541
  • A mechanistic growth model for inorganic crystals: Growth mechanism
    • Authors: Preshit Dandekar; Michael F. Doherty
      Abstract: Inorganic crystals grown from solution find wide application. We present a mechanistic growth model based on the spiral growth mechanism that operates at low supersaturation on inorganic crystal surfaces. The long-range electrostatic interactions on inorganic crystal surfaces are captured by methods developed in our previous paper1. The interactions of kink site growth units with the solvent molecules partially determine the growth kinetics. Relevant experimental parameters are systematically accounted for in the expression for the kink incorporation rate along step edges on the crystal surfaces. The growth model accurately predicts the asymmetric growth spirals on the (101¯4) surface of calcite crystals. The effect of supersaturation and ionic activity ratio on the step velocities of the acute and obtuse spiral edges is correctly captured. This model can be used to predict the shapes of solution grown inorganic crystals and to engineer the growth process to design inorganic solids with functionally desirable shapes. © 2014 American Institute of Chemical Engineers AIChE J, 2014
      PubDate: 2014-05-28T08:30:09.968276-05:
      DOI: 10.1002/aic.14513
  • Process data analytics in the era of big data
    • Authors: S. Joe Qin
      Pages: 3092 - 3100
      PubDate: 2014-07-02T21:40:20.33506-05:0
      DOI: 10.1002/aic.14523
  • Rapid and large‐scale separation of magnetic nanoparticles by
           low‐field permanent magnet with gas assistance
    • Authors: Wensong Li; Liangrong Yang, Huizhou Liu, Xiaopei Li, Zhini Liu, Fuchun Wang, Na Sui, Chuanxu Xiao
      Pages: 3101 - 3106
      Abstract: Bubbles can be used to greatly improve the speed of magnetic separation (MS) and overcome the limitation of magnetic force on the capture distance, making low‐field MS highly efficient and easily scalable. This novel method leads to the development of a medium‐free continuous gas‐assisted magnetic separator on small pilot scale using low‐field permanent magnet. This separator is demonstrated highly efficient for recovery of proteins‐loaded magnetic nanoparticles from large volume biosuspension. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3101–3106, 2014
      PubDate: 2014-06-30T14:26:45.782779-05:
      DOI: 10.1002/aic.14533
  • A novel fluidized and induction heated microreactor for catalyst testing
    • Authors: Mohammad Latifi; Franco Berruti, Cedric Briens
      Pages: 3107 - 3122
      Abstract: The jiggled bed reactor (JBR) is a state‐of‐the‐art batch fluidized microreactor designed and developed to test catalysts for endothermic reactions. The solid particles in the microreactor are mechanically fluidized by agitating the reactor using a linear pneumatic actuator. An external induction field heats up vertical metal wires installed inside the reactor bed to generate heat rapidly and uniformly within the bed of solid particles, while eliminating hot spots and large temperature gradients. Image and signal processing techniques were utilized to investigate how the fluidization dynamics of the solid particles are affected by the amplitude and frequency of the vibrations, and the size distribution and the mass of the particles. The results show that the microreactor is very flexible: operating conditions can be optimized to successfully fluidize any type of catalyst. Heat‐transfer coefficients between heating surfaces and the bed are similar to the coefficients that could be obtained in a well‐bubbling fluidized bed. This confirms the excellent quality of the fluidization achieved with the new JBR. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3107–3122, 2014
      PubDate: 2014-06-02T15:47:15.746576-05:
      DOI: 10.1002/aic.14492
  • A novel multiple linear multivariate NIR calibration model‐based
           strategy for in‐line monitoring of continuous mixing
    • Authors: Leonel Quiñones; Carlos Velazquez, Luis Obregon
      Pages: 3123 - 3132
      Abstract: The capability of near infra‐red (NIR) spectroscopy to predict many different variables, such as concentration and humidity, has been demonstrated in many published works. Several of those articles have been in the subject of real time prediction of continuous operations. However, those demonstrations have been for narrow ranges of the variables, especially for powder concentration, which could present a nonlinear behavior of the NIR absorbance as a function of the entire range of concentration. This work developed a novel strategy to predict the entire range of powder concentration using multiple linear NIR calibration models. The root mean standard error of prediction and relative standard deviation (RSD) parameters were used to establish the number of the multiple linear calibration models; other statistical features were used to establish the correct prediction. It was found that a minimum number of linear partial least squares (PLS) calibration models were necessary to accurately predict the range from 0 to 100% w/w. This technique could also be used with other nonlinear behaviors. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3123–3132, 2014
      PubDate: 2014-06-02T16:12:27.884136-05:
      DOI: 10.1002/aic.14498
  • Improved magnetic particle tracking technique in dense gas fluidized beds
    • Authors: Kay A. Buist; Alex C. Gaag, Niels G. Deen, Johannes A. M. Kuipers
      Pages: 3133 - 3142
      Abstract: Noninvasive monitoring of multiphase flow is rapidly gaining increased interest. More specifically noninvasive particle tracking techniques have received a lot of attention in recent years to study dense granular flow. However, these techniques are usually quite expensive and require strict safety measures. An improved magnetic particle tracking (MPT) technique for dense granular flow will be presented in this article. The improvements of the analysis technique for MPT will be demonstrated and rigorously tested with a three‐dimensional system and two‐dimensional sensor system. The strengths and limitations of the MPT technique will also be reported. Finally, the results of the MPT are compared with data obtained from a combined particle image velocimetry and digital image analysis technique. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3133–3142, 2014
      PubDate: 2014-06-04T14:06:30.925908-05:
      DOI: 10.1002/aic.14512
  • A multi‐point electrical resistance measurement system for
           characterization of foam drainage regime and stability
    • Authors: Chanhyuk Park; Slawomir W. Hermanowicz
      Pages: 3143 - 3150
      Abstract: Foam drainage regimes are significantly associated with the nature of the hydrodynamic resistance in foam structure. A multi‐point electrical resistance measurement technique has been applied for characterization of the drainage regimes and quantifying stability within standing foams. The capacity of the technique was confirmed by the estimation of macroscopic drainage rates for aqueous foams stabilized with sodium dodecyl sulfate. The drainage of sodium dodecylbenzenesulfonate, a commercial form of linear alkylbenzene sulfonate that is the most frequently used in household detergents was studied in detail by two complementary methods (forced and free drainage). The experimental data could be fitted using a power‐law with an exponent of 1/3 for forced drainage and of 1.0 for free drainage. These data indicate the following drainage behavior: mobile bubble surfaces, causing plug‐like flow within Plateau borders, thus dissipation mainly occurs inside the nodes. This research introduced an accurate method for quantifying foam stability that can be assessed by variations of real‐time measured foam heights that incorporate the evolution of the liquid content. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3143–3150, 2014
      PubDate: 2014-05-20T11:47:06.931768-05:
      DOI: 10.1002/aic.14489
  • Design under uncertainty using parallel multiperiod dynamic optimization
    • Authors: Ian D. Washington; Christopher L. E. Swartz
      Pages: 3151 - 3168
      Abstract: A technique for optimizing dynamic systems under uncertainty using a parallel programming implementation is developed in this article. A multiple‐shooting discretization scheme is applied, whereby each shooting interval is solved using an error‐controlled differential equation solver. In addition, the uncertain parameter space is discretized, resulting in a multiperiod optimization formulation. Each shooting interval and period (scenario) realization is completely independent, thus a major focus of this article is on demonstrating potential computational performance improvement when the embedded dynamic model solution of the multiperiod algorithm is implemented in parallel. We assess our parallel multiperiod and multiple‐shooting‐based dynamic optimization algorithm on two case studies involving integrated plant and control system design, where the objective is to simultaneously determine the size of the process equipment and the control system tuning parameters that minimize cost, subject to uncertainty in the disturbance inputs. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3151–3168, 2014
      PubDate: 2014-05-23T15:44:05.904437-05:
      DOI: 10.1002/aic.14473
  • Integration of scheduling and control for batch processes using
           multi‐parametric model predictive control
    • Authors: Jinjun Zhuge; Marianthi G. Ierapetritou
      Pages: 3169 - 3183
      Abstract: Integration of scheduling and control results in Mixed Integer Nonlinear Programming (MINLP) which is computationally expensive. The online implementation of integrated scheduling and control requires repetitively solving the resulting MINLP at each time interval. (Zhuge and Ierapetritou, Ind Eng Chem Res. 2012;51:8550–8565) To address the online computation burden, we incorporare multi‐parametric Model Predictive Control (mp‐MPC) in the integration of scheduling and control. The proposed methodology involves the development of an integrated model using continuous‐time event‐point formulation for the scheduling level and the derived constraints from explicit MPC for the control level. Results of case studies of batch processes prove that the proposed approach guarantees efficient computation and thus facilitates the online implementation. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3169–3183, 2014
      PubDate: 2014-06-03T14:23:27.760744-05:
      DOI: 10.1002/aic.14509
  • Discrete element reduced‐order modeling of dynamic particulate
    • Authors: Amanda Rogers; Marianthi G. Ierapetritou
      Pages: 3184 - 3194
      Abstract: One of the key technical challenges associated with modeling particulate processes is the ongoing need to develop efficient and accurate predictive models. Often the models that best represent solids handling processes, like discrete element method (DEM) models, are computationally expensive to evaluate. In this work, a reduced‐order modeling (ROM) methodology is proposed that can represent distributed parameter information, like particle velocity profiles, obtained from high‐fidelity (DEM) simulations in a more computationally efficient fashion. The proposed methodology uses principal component analysis (PCA) to reduce the dimensionality of the distributed parameter information, and response surface modeling to map the distributed parameter data to process operating parameters. This PCA‐based ROM approach has been used to model velocity trajectories in a continuous convective mixer, to demonstrate its applicability for pharmaceutical process modeling. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3184–3194, 2014
      PubDate: 2014-06-05T15:36:37.692167-05:
      DOI: 10.1002/aic.14505
  • Global optimization for sustainable design and synthesis of algae
           processing network for CO2 mitigation and biofuel production using life
           cycle optimization
    • Authors: Jian Gong; Fengqi You
      Pages: 3195 - 3210
      Abstract: Global optimization for sustainable design and synthesis of a large‐scale algae processing network under economic and environmental criteria is addressed. An algae processing network superstructure including 7800 processing routes is proposed. Based on the superstructure, a multiobjective mixed‐integer nonlinear programming (MINLP) model is developed to simultaneously optimize the unit cost and the unit global warming potential (GWP). To efficiently solve the nonconvex MINLP model with separable concave terms and mixed‐integer fractional terms in the objective functions, a global optimization strategy that integrates a branch‐and‐refine algorithm based on successive piecewise linear approximations is proposed and an exact parametric algorithm based on Newton's method. Two Pareto‐optimal curves are obtained for biofuel production and biological carbon sequestration, respectively. The unit annual biofuel production cost ranges from $7.02/gasoline gallon equivalent (GGE) to $9.71/GGE, corresponding to unit GWP's of 26.491 to 16.52 kg CO2‐eq/GGE, respectively. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3195–3210, 2014
      PubDate: 2014-06-09T11:41:41.001215-05:
      DOI: 10.1002/aic.14504
  • Fair profit allocation in supply chain optimization with transfer price
           and revenue sharing: MINLP model and algorithm for cellulosic biofuel
           supply chains
    • Authors: Dajun Yue; Fengqi You
      Pages: 3211 - 3229
      Abstract: A mixed‐integer nonlinear programming (MINLP) formulation to simultaneously optimize operational decisions as well as profit allocation mechanisms in supply chain optimization, namely material transfer prices and revenue share policies among the supply chain participants is proposed. The case of cellulosic bioethanol supply chains is specifically considered and the game‐theory Nash bargaining solution approach is employed to achieve fair allocation of profit among the collection facilities, biorefineries, and distribution centers. The structural advantages of certain supply chain participants can be taken into account by specifying different values of the negotiation‐power indicators in the generalized Nash‐type objective function. A solution strategy based on a logarithm transformation and a branch‐and‐refine algorithm for efficient global optimization of the resulting nonconvex MINLP problem is proposed. To demonstrate the application of the proposed framework, an illustrative example and a state‐wide county‐level case study on the optimization of a potential cellulosic bioethanol supply chain in Illinois are presented. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3211–3229, 2014
      PubDate: 2014-06-09T11:41:31.747333-05:
      DOI: 10.1002/aic.14511
  • Selection of control configurations for economic model predictive control
    • Authors: Matthew Ellis; Panagiotis D. Christofides
      Pages: 3230 - 3242
      Abstract: Economic model predictive control (EMPC) is a feedback control method that dictates a potentially dynamic (time‐varying) operating policy to optimize the process economics. The objective function used in the EMPC system may be a general nonlinear function that describes the process/system economics. As this function is not derived on the sole basis of classical control considerations (stabilization, tracking, and optimal control action calculation) but rather on the basis of economics, selecting the appropriate control configuration, and quantifying the influence of a given input on an economic cost is an important task for the proper design and computational efficiency of an EMPC scheme. Owing to these considerations, an input selection methodology for EMPC is proposed which utilizes the relative degree and the sensitivity of the economic cost with respect to an input to identify and select stabilizing manipulated inputs with the most dynamic and steady‐state influence on the economic cost function to be assigned to EMPC. Other considerations for input selection for EMPC are also discussed and integrated into a proposed input selection methodology for EMPC. The control configuration selection method for EMPC is demonstrated using a chemical process example. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3230–3242, 2014
      PubDate: 2014-06-09T12:03:53.126585-05:
      DOI: 10.1002/aic.14514
  • Optimal design of large‐scale chemical processes under uncertainty:
           A ranking‐based approach
    • Authors: Sami S. Bahakim; Shabnam Rasoulian, Luis A. Ricardez‐Sandoval
      Pages: 3243 - 3257
      Abstract: An approach for the optimal design of chemical processes in the presence of uncertainty was presented. The key idea in this work is to approximate the process constraint functions and model outputs using Power Series Expansions (PSE)‐based functions. The PSE functions are used to efficiently identify the variability in the process constraint functions and model outputs due to multiple realizations in the uncertain parameters using Monte Carlo (MC) sampling methods. A ranking‐based approach is adopted here where the user can assign priorities or probabilities of satisfaction for the different process constraints and model outputs considered in the analysis. The methodology was tested on a reactor–heat exchanger system and the Tennessee Eastman process. The results show that the present method is computationally attractive since the optimal process design is accomplished in shorter computational times when compared to the use of the MC method applied to the full plant model. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3243–3257, 2014
      PubDate: 2014-06-11T16:15:38.394145-05:
      DOI: 10.1002/aic.14515
  • Process flow sheet synthesis: Reaching targets for idealized coal
    • Authors: James Alistair Fox; Diane Hildebrandt, David Glasser, Bilal Batel, Brendon Hausberger
      Pages: 3258 - 3266
      Abstract: The gasification of coal is a process that has been commonly used to produce a mixture of gases containing primarily carbon dioxide and hydrogen, called syngas. This syngas is used as an intermediate in the production of many chemicals such as ammonia, synthetic hydrocarbons, and methanol (to name a few). Coal gasification has a reputation for being “dirty” in terms of its emissions in comparison with other syngas creation technologies, such as methane reforming. However, there is remarkably little information on what the “best case” for coal gasification could actually be and how existing process perform relative to that “best case.” The goal of this article is to formulate a preliminary and conceptual flow sheet for the gasification process; this flow sheet is not intended to be a finalized design or a definitive solution. It is intended to illustrate the method of setting and achieving design objectives and provide a basis of comparison for either new or existing processes. Thermodynamics can be used to describe any process, or system of processes. Of particular interest are the properties of enthalpy and Gibbs free energy. Using these two thermodynamic properties together as vectors on a diagram of free energy (ΔG) against enthalpy (ΔH), it becomes possible to develop better process flow sheets that combine the thermodynamics of chemical reactions and the dynamics of physical operations on a single diagram. This article will discuss the selection of the independent mass balances that best describe the process as a whole, then the choosing of design objectives, how these objectives might be achieved, and their implications for the process as a whole. Using these ideas one is able to show how to improve the carbon and operating efficiency of a gasification process, making the process more reversible. It was found that there will always be a price to pay for using coal as the feedstock for creating synthesis gas but there is room for improvement, most notably in how combustion is carried out and how energy is used internally within a process. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3258–3266, 2014
      PubDate: 2014-06-16T16:02:44.507959-05:
      DOI: 10.1002/aic.14521
  • Insight into the intraparticle diffusion of residue oil components in
           catalysts during hydrodesulfurization reaction
    • Authors: Zhigang Wang; Sheng‐Li Chen, Jianing Pei, Aicheng Chen, Junhui Zhang, Zhiming Xu, Jay B. Benziger
      Pages: 3267 - 3275
      Abstract: Well‐defined and uniform pore structure catalysts were used to study the intraparticle diffusion of fractionated Saudi vacuum residue under hydrodesulfurization (HDS) reaction conditions. HDS rates of residue oil cuts with different molecular weights are determined as functions of pore size, temperature, and pressure in a trickle‐bed reactor. Credible intrinsic and bulk diffusivities of organosulfur compounds in residue oil were obtained for the first time, from the apparent and intrinsic reaction kinetic constants. Intrinsic diffusivities ranged from 2 × 10−7 to 8 × 10−7 cm2/s for the residual oil molecules; diffusivity decreases with increasing molecular weight of the residual oil. The intrinsic diffusivity for molecular weights ∼1000 Daltons increases with pore size for pores 70 nm. The diffusivity dependences on pore size and molecular weight suggest that the onset of restricted diffusion occurs for ratios of molecular diameter to pore diameter of ∼0.04. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3267–3275, 2014
      PubDate: 2014-06-02T16:05:51.775636-05:
      DOI: 10.1002/aic.14501
  • Modeling for primary radical desorption in miniemulsion polymerization
           initiated by oil‐soluble initiator
    • Authors: Yue Shang; Guorong Shan, Pengju Pan
      Pages: 3276 - 3285
      Abstract: Primary radical (PR) desorption in the miniemulsion polymerization initiated by oil‐soluble initiator was investigated. Both the aqueous phase inhibition experiments and the theoretical predictions, which combined the two film theory and aqueous phase mass balance, were performed to evaluate the PR desorption process quantitatively. The theoretical predictions agreed well with the experiment results. It was found that the organic phase diffusion, particle size, surfactant layer, aqueous phase resistance, and different initiator type affected the PR desorption. The desorption rate of PR was faster than its reaction rate at the early stage of polymerization, while the former decreased to a comparable level as the latter at the high conversion. PR was prone to desorb in the polymerization and the desorption of PR played a critical role in the miniemulsion polymerization initiated by oil‐soluble initiator. It is concluded that the PR desorption–reabsorption is a process to generate effective radicals in the miniemulsion polymerization initiated by oil‐soluble initiator. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3276–3285, 2014
      PubDate: 2014-06-02T16:01:35.929478-05:
      DOI: 10.1002/aic.14506
  • Photocatalytic degradation of malic acid using a thin coated
           TiO2‐film: Insights on the mechanism of photocatalysis
    • Authors: Vanessa Rodgher; Jesus Moreira, Hugo Lasa, Benito Serrano
      Pages: 3286 - 3299
      Abstract: Decontamination of opaque fluids using photocatalysts and near Ultraviolet (UV) irradiation involves major technical challenges. This study considers a thin TiO2 layer placed in a new Chemical Reactor Engineering Centre (CREC)‐photoreactor cell. This new photoreactor cell is used for the photocatalytic degradation of malic and malonic acids, typical apple juice components. Conversion of organic species can only proceed through the “dark side” of the TiO2 layer, which is in direct contact with the fluid. Under the selected operating conditions both external mass‐transfer limitations and photolysis are found to be negligible. Macroscopic radiation balance shows that 92% of near UV radiation is absorbed by the ‘back side” of the TiO2‐film. Photocatalytic degradation experiments with 10, 20, 30, and 40 ppm malic acid initial concentrations, show that malonic acid is a main intermediate. Complete malic acid conversion occurs after 5–8 h of irradiation. Kinetic modeling of malic and malonic acid photodegradation with kinetic parameter estimation is performed using both an “in series” and an “in series‐parallel” reaction networks. The “in series‐parallel” reaction network displays better ability for predicting CO2 formation, showing maximum quantum yields of 14.2%. Given that in the CREC‐photoreactor cell with a thin TiO2‐film, photocatalysis can only proceed via the transfer of mobile “h+” sites from the irradiated side to the “dark side', this study demonstrates the significance of this step on the overall photocatalysis mechanism. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3286–3299, 2014
      PubDate: 2014-06-05T15:31:56.267782-05:
      DOI: 10.1002/aic.14500
  • Liquid‐phase hydrogenation of cinnamaldehyde over Cu‐Au/SiO2
    • Authors: Xiang Yuan; Jianwei Zheng, Qian Zhang, Shuirong Li, Yanhui Yang, Jinlong Gong
      Pages: 3300 - 3311
      Abstract: The synthesis, characterization, and application of silica‐supported Cu‐Au bimetallic catalysts in selective hydrogenation of cinnamaldehyde are described. The results showed that Cu‐Au/SiO2 bimetallic catalysts were superior to monometallic Cu/SiO2 and Au/SiO2 catalysts under identical conditions. Adding a small amount of gold (6Cu‐1.4Au/SiO2 catalyst) afforded eightfold higher catalytic reaction rate compared to Cu/SiO2 along with the high selectivity (53%, at 55% of conversion) toward cinnamyl alcohol. Characterization techniques such as x‐ray diffraction, H2 temperature‐programmed reduction, ultraviolet‐visible spectroscopy, transmission electron microscopy, Fourier‐transform infrared spectra of chemisorbed CO, and x‐ray photoelectron spectroscopy were employed to understand the origin of the catalytic activity. A key genesis of the high activity of the Cu‐Au/SiO2 catalyst was ascribed to the synergistic effect of Cu and Au species: the Au sites were responsible for the dissociative activation of H2 molecules, and Cu0 and Cu+ sites contributed to the adsorption‐activation of CC and CO bond, respectively. A combined tuning of particle dispersion and its surface electronic structure was shown as a consequence of the formation of Au‐Cu alloy nanoparticles, which led to the significantly enhanced synergy. A plausible reaction pathway was proposed based on our results and the literature. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3300–3311, 2014
      PubDate: 2014-06-25T14:32:19.004859-05:
      DOI: 10.1002/aic.14522
  • Extractive distillation with ionic liquids: A review
    • Authors: Zhigang Lei; Chengna Dai, Jiqin Zhu, Biaohua Chen
      Pages: 3312 - 3329
      Abstract: Extractive distillation is commonly used for the separation of azeotropic or close‐boiling mixtures in the chemical industry. During the past decade, the use of ionic liquids (ILs) as entrainers has received considerable attention due to their unique advantages when applied in extractive distillation. This work is devoted to providing an easy‐to‐read and comprehensive review on the recent progress made by chemical engineers, focusing on the issues of predictive thermodynamic models, structure‐property relations, separation mechanisms, and process simulation and optimization. This review spans from the molecular level to the industrial scale, to provide a theoretical insight into the molecular interactions between ILs and the components to be separated. Moreover, a comprehensive database on the vapor–liquid equilibria and activity coefficients at infinite dilution concerning ILs is provided as Supporting Information. Concluding remarks are made on the unsolved scientific issues with respect to this promising special distillation technology. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3312–3329, 2014
      PubDate: 2014-07-02T21:17:57.327416-05:
      DOI: 10.1002/aic.14537
  • Novel design and performance of a medical oxygen concentrator using a
           rapid pressure swing adsorption concept
    • Authors: Vemula Rama Rao; Mayuresh V. Kothare, Shivaji Sircar
      Pages: 3330 - 3335
      Abstract: A novel design of a compact rapid pressure swing adsorption system consisting of a single adsorber enclosed inside a product storage tank is proposed for application as a medical oxygen concentrator (MOC). A self‐contained test unit for the process is constructed which is capable of directly and continuously producing 1–3 sl/m of 90% O2 from compressed air. Pelletized LiLSX zeolite is used as the air separation adsorbent. Steady state process performance data [bed size factor (BSF) and O2 recovery (R) as functions of total cycle time (tc)], as well as transient, cyclic, adsorber pressure, and temperature profiles are presented. A four‐step Skarstrom‐like pressure swing adsorption cycle was used. Two options for column pressurization, (a) using compressed feed air cocurrently or (b) using a part of the oxygen‐enriched product gas counter‐currently were evaluated. Option (b) exhibited superior performance. The optimum total cycle time for option (b) was 5–6 s where the BSF was lowest (∼45 kgs/TPD O2) and the corresponding R was ∼29.3%. These numbers indicate that the adsorbent inventory of a MOC can be potentially reduced by a factor of three while offering a ∼10–20% higher O2 recovery compared to a typical commercial unit. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3330–3335, 2014
      PubDate: 2014-06-16T16:31:43.759152-05:
      DOI: 10.1002/aic.14518
  • Critical isotherms from virial series using asymptotically consistent
    • Authors: Nathaniel S. Barlow; Andrew J. Schultz, David A. Kofke, Steven J. Weinstein
      Pages: 3336 - 3349
      Abstract: The low‐density equation of state of a fluid along its critical isotherm is considered. An asymptotically consistent approximant is formed having the correct leading‐order scaling behavior near the vapor‐liquid critical point, while retaining the correct low‐density behavior as expressed by the virial equation of state. The formulation is demonstrated for the Lennard–Jones fluid, and models for helium, water, and n‐alkanes. The ability of the approximant to augment virial series predictions of critical properties is explored, both in conjunction with and in the absence of critical‐property data obtained by other means. Given estimates of the critical point from molecular simulation or experiment, the approximant can refine the critical pressure or density by ensuring that the critical isotherm remains well‐behaved from low density to the critical region. Alternatively, when applied in the absence of other data, the approximant remedies a consistent underestimation of the critical density when computed from the virial series alone. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3336–3349, 2014
      PubDate: 2014-06-25T14:16:52.127041-05:
      DOI: 10.1002/aic.14531
  • The formation and breakup of molten oxide jets under periodic excitation
    • Authors: Mirco Wegener; Luckman Muhmood, Shouyi Sun, Alex V. Deev
      Pages: 3350 - 3361
      Abstract: The experiments on the capillary breakup of slag jets at high temperatures are presented in this article. The impact of external excitations on the disintegration process was investigated in a furnace with optical access filmed at frame rates up to 10,000 fps. A synthetic calcia‐alumina slag was used to form jets at different temperatures (1570–1660°C) and jet velocities (0.6–1.4 ms−1). The impact of external vibration on the breakup was evident: for low jet velocities, the jet length decreased, the droplet size increased, satellite droplet formation was hindered, and a distinct “pumping mechanism” was observed. For jets with higher velocity, the jet length decreased by 30%, the droplet generation frequency increased from 20 to 250 droplets per second, the drop sizes were uniform, and satellite formation was also suppressed. In this case, the ideal case in which the volume of one wave instability forms one droplet was achieved. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3350–3361, 2014
      PubDate: 2014-05-13T16:11:29.399408-05:
      DOI: 10.1002/aic.14485
  • Sensor‐based flow pattern
           detection—gas–liquid–liquid upflow through a vertical
    • Authors: Tanumoy Mukherjee; Gargi Das, Subhabrata Ray
      Pages: 3362 - 3375
      Abstract: Flow distribution during gas–liquid–liquid upflow through a vertical pipe is investigated. The optical probe technique has been adopted for an objective identification of flow patterns. The probability density function (PDF) analysis of the probe signals has been used to identify the range of existence of the different patterns. Dispersed and slug flow have been identified from the nature of the PDF, which is bimodal for slug flow and unimodal for dispersed flow. The water continuous, oil continuous, and emulsion type flow distributions are distinguished on the basis of the PDF moments. The method is particularly useful at high flow rates where visualization techniques fail. Based on this, a flow pattern detection algorithm has been presented. Two different representations of flow pattern maps have been suggested for gas–liquid–liquid three phase flow. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3362–3375, 2014
      PubDate: 2014-05-14T13:14:27.138398-05:
      DOI: 10.1002/aic.14488
  • Mass‐transfer enhancement by a reversible chemical reaction across
           the interface of a bubble rising under Stokes flow
    • Authors: Franck Pigeonneau; Marion Perrodin, Eric Climent
      Pages: 3376 - 3388
      Abstract: Mass transfer around a bubble rising in a liquid under Stokes regime is investigated when a reversible chemical reaction, A⇄B, is taken into account. Four dimensionless parameters control the interfacial transfer rate: the Péclet and Damköhler numbers, the ratio of the diffusion coefficient of both species, and the reaction equilibrium constant. The mass‐transfer equations are solved numerically with a finite element technique. A boundary layer approach is also proposed and solved with a coupled technique of finite difference and Chebyshev‐spectral method. The equilibrium constant and the ratio of diffusion coefficients have a strong influence on the coupling between the chemical reaction and mass transfer leading to an increase of the Sherwood number. The interaction between the chemical reaction and advection is clearly established by the simulations. Conditions corresponding to Péclet number larger than the Damköhler number reduces the effect of the chemical reaction. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3376–3388, 2014
      PubDate: 2014-06-18T19:04:29.051011-05:
      DOI: 10.1002/aic.14520
  • Retraction
    • Authors: X. Fan; Z. Yang, D. J. Parker
      Pages: 3389 - 3389
      PubDate: 2007-06-14T00:00:00-05:00
      DOI: 10.1002/aic.11232
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